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Unit 24: Unknown 2- Mixed Culture - Biology


Unit 24: Unknown 2- Mixed Culture

The Mismeasure of Man

The Mismeasure of Man is a 1981 book by paleontologist Stephen Jay Gould. [1] The book is both a history and critique of the statistical methods and cultural motivations underlying biological determinism, the belief that "the social and economic differences between human groups—primarily races, classes, and sexes—arise from inherited, inborn distinctions and that society, in this sense, is an accurate reflection of biology". [2]

Gould argues that the primary assumption underlying biological determinism is that, "worth can be assigned to individuals and groups by measuring intelligence as a single quantity". Biological determinism is analyzed in discussions of craniometry and psychological testing, the two principal methods used to measure intelligence as a single quantity. According to Gould, these methods possess two deep fallacies. The first fallacy is reification, which is "our tendency to convert abstract concepts into entities". [3] Examples of reification include the intelligence quotient (IQ) and the general intelligence factor (g factor), which have been the cornerstones of much research into human intelligence. The second fallacy is that of "ranking", which is the "propensity for ordering complex variation as a gradual ascending scale". [3]

The book received many positive reviews in the literary and popular press, including many written by scientists, while other reviews in scientific journals were highly critical. [4] Literary reviews praised the book for opposing racism, the concept of general intelligence, and biological determinism. [4] Reviews in scientific journals accused Gould of historical inaccuracy, unclear reasoning, and political bias. [4] The Mismeasure of Man won the National Book Critics Circle award. [4] Gould's findings about how 19th-century researcher Samuel George Morton measured skull volumes came under criticism, and even Gould's defenders found reasons to criticize his work on this topic.

In 1996, a second edition was released. It included two additional chapters critiquing Richard Herrnstein and Charles Murray's book The Bell Curve (1994).


Complex and Synthetic Media

In defined media all the chemical compounds are known, while undefined media has partially unknown chemical constituents.

Learning Objectives

Differentiate complex and synthetic medias

Key Takeaways

Key Points

  • Defined media is made from constituents that are completely understood.
  • Undefined media has some part of which is not entirely defined.
  • The presence of extracts from animals or other microbes makes a media undefined as the entire chemical composition of extracts are not completely known.

Key Terms

  • recombinant: This term refers to something formed by combining existing elements in a new combination. Thus, the phrase recombinant DNA refers to an organism created in the lab by adding DNA from another species.
  • serum: The clear yellowish fluid obtained upon separating whole blood into its solid and liquid components after it has been allowed to clot. Also called blood serum.

There are many types of culture media, which is food that microbes can live on. Two major sub types of media are complex and synthetic medias, known as undefined and defined media.

Undefined Media: Luria Broth as shown here is made with yeast extract, as yeast extract is not completely chemically defined Luria Broth is therefore an undefined media. By Lilly_M [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA, via Wikimedia Commons

An undefined medium has some complex ingredients, such as yeast extract or casein hydrolysate, which consist of a mixture of many, many chemical species in unknown proportions. Undefined media are sometimes chosen based on price and sometimes by necessity – some microorganisms have never been cultured on defined media.A defined medium (also known as chemically defined medium or synthetic medium) is a medium in which all the chemicals used are known, no yeast, animal, or plant tissue is present. A chemically defined medium is a growth medium suitable for the culture of microbes or animal cells (including human) of which all of the chemical components are known. The term chemically defined medium was defined by Jayme and Smith as a ‘Basal formulation which may also be protein-free and is comprised solely of biochemically-defined low molecular weight constituents.

A chemically defined medium is entirely free of animal-derived components (including microbial derived components such as yeast extract) and represents the purest and most consistent cell culture environment. By definition chemically defined media cannot contain either fetal bovine serum, bovine serum albumin, or human serum albumin as these products are derived from bovine or human sources and contain complex mixes of albumins and lipids. The term ‘chemically defined media’ is often misused in the literature to refer to serum albumin-containing media. Animal serum or albumin is routinely added to culture media as a source of nutrients and other ill-defined factors, despite technical disadvantages to its inclusion and its high cost. Technical disadvantages to using serum include the undefined nature of serum, batch-to-batch variability in composition, and the risk of contamination. There are increasing concerns about animal suffering inflicted during serum collection that add an ethical imperative to move away from the use of serum wherever possible. Chemically defined media differ from serum-free media in that bovine serum albumin or human serum albumin with either a chemically defined recombinant version (which lacks the albumin associated lipids) or synthetic chemical such as the polymer polyvinyl alcohol which can reproduce some of the functions of serums.


How to Calculate Dilution Solutions

A dilution solution contains solute (or stock solution) and a solvent (called diluent). These two components proportionally combine to create a dilution. You can identify a dilution solution by the amount of solute in the total volume, expressed as a proportion. For example, a chemical may be prepared in a 1:10 dilution of alcohol, indicating that a 10 mL bottle contains one milliliter of chemical and nine milliliters of alcohol. You can calculate the necessary volume of each component to prepare a dilution solution.

Write down the desired final volume of the solution--for example, 30 mL.

Write down the desired dilution in the form of a proportion--for example, 1:20 dilution, also known as the dilution factor.

Convert the dilution factor to a fraction with the first number as the numerator and the second number as the denominator. For example, a 1:20 dilution converts to a 1/20 dilution factor.

Multiply the final desired volume by the dilution factor to determine the needed volume of the stock solution. In our example, 30 mL x 1 ÷ 20 = 1.5 mL of stock solution.

Subtract this figure from the final desired volume to calculate the volume of diluent required--for example, 30 mL - 1.5 mL = 28.5 mL.

Measure the amount of stock solution required -- in our example, 1.5 mL -- and dispense this into a large measuring cup.

Measure the amount of diluent required -- in our example, 28.5 mL -- and dispense this into the large measuring cup.

Mix the solution with the glass stirring rod. You now have your 1:20 dilution solution.


Discussion

As its high pathogenicity and the lack of effective therapeutics, SARS-CoV-2 is classified as a biological safety level 3 (BSL-3) pathogen[39], which has hindered the drug discovery and biological research due to biocontainment requirements. In this study, we developed an in vitro cell culture system to produce the recombinant SARS-CoV-2 virus lacking the N-encoding region in the viral genome (SARS-CoV-2 ΔN). Recombinant SARS-CoV-2 ΔN virus can expand and propagate in packaging cells (Caco-2-N) but results in only single-cycle infection in naïve Caco-2 cells, which biologically contained the virus in the cells expressing N protein. This BSL-2 SARS-CoV-2 possesses a reporter gene GFP, providing a surrogate readout for authentic viral infection. We monitored the recombinant virus infection in the Caco-2-N cells for one month and NGS sequencing result suggested that no recombination was detected. In addition, we utilized the split intein-mediated protein ligation to reconstitute N function which further ensure the biosafety of this system. However, we have not performed the recombination analysis in Caco-2-N or Caco-2-N intein cells co-infection of SARS-CoV-2 trVLP with WT SARS-CoV-2 or other related beta-coronaviruses, which could potentially increase the risk of the recombination and need further investigation.

This cell model represents a unique system in the basic research application for better understanding SARS-CoV-2 life cycle. Virus has evolved since its outbreak in the end of 2019, and some mutations or deletions have been observed. However, the functional consequences of these mutations or deletions on virus infectivity or pathogenesis are poorly characterized. Herein, we utilized our model system to study the roles of N in the SARS-CoV-2 life cycle. Since N can be expressed alone in trans, it is convenient to perform mutagenesis on N to dissect its detailed function. Moreover, the introduction of mutations in trans-expressed N will avoid the cis effects of the mutations, for example, the disruption of critical RNA secondary or tertiary structures in the SARS-CoV-2 genome, thereby providing a more appropriate system to specifically evaluate the biological roles of domains, motifs, or amino acid residues within the N protein. Additionally, we inserted a Flag tag at the C terminus of N, which did not impair the ability of N to rescue viral production. With this Flag tag, N can be detected and immunoprecipitated by an anti-Flag antibody (S4A Fig). Multiple amino acids in N protein can be phosphorylated, but our data demonstrated that most of these phosphorylation may not be required for N function at least in vitro. Meanwhile, we also identified numerous host factors associated with N protein (S4A Fig and S2 Table), notably, we also found that N protein could interact with G3BP1 and G3BP2, the stress granule assembly proteins, which was in line with previous studies[40�]. Recent studies found that N protein could impair the stress granule assembly to escape the antiviral effect[41,43]. Thus, the trVLP system provides a new tool to study host factors and viral proteins that may interact with N during SARS-CoV-2 infection.

Development of effective therapeutics for COVID-19 remains an urgently unmet medical need. This recombinant trVLP recapitulates the complete SARS-CoV-2 life cycle in the Caco-2-N or Caco-2-N intein cells. The reporter readout of the virus, such as fluorescent proteins or luminescent proteins, offers a rapid, real-time, quantitative and less labor-intensive measure than traditional methods of viral titer reduction assay. Importantly, the reporter virus-based assay could cooperate with a BSL-2 compatible high-content screening platform to facilitate antiviral screening. Thus, we developed a 96-well format to screen the antiviral compounds in the Topscience Natural Compounds Library, and we identified five compounds which could efficiently block SARS-CoV-2 infection. Among them, lycorine, salinomycin and monensin have been reported as the potent inhibitors against HCoV-OC43 infection[36], and salinomycin could block SARS-CoV-2 infection as reported recently[38]. Those data further validate the suitability of our trVLP system in drug discovery. In our screening, we identified Tubeimoside I and nigericin sodium as novel compounds which exhibited potent antiviral activities against authentic SARS-CoV-2 infection in vitro. Future studies could be performed to evaluate their antiviral activities in vivo.

Additionally, there is an urgently need for effective vaccines to contain SARS-CoV-2 pandemic[39]. The recombinant SARS-CoV-2 lacking of N gene should provide a new means of vaccine development. The greatest advantage of SARS-CoV-2 ΔN is that this virus possesses all the structural viral proteins to induce humoral immune responses and that, upon infection, it could produce all the nonstructural viral proteins in host cells to induce cell-mediated immune responses. Of course, further studies, especially in animals, are needed to determine the immunogenicity, safety, and efficacy of it.

In summary, the biologically contained SARS-CoV-2 trVLP lacking the N gene represents a safe, alternative experimental system to study SARS-CoV-2 biology and to screen antiviral compounds and this novel system will greatly accelerate current SARS-CoV-2 research efforts.


Bile Esculin Agar

This is a medium that is both selective and differential. It tests the ability of organisms to hydrolyze esculin in the presence of bile. It is commonly used to identify members of the genus Enterococcus (E faecalis and E. faecium).

The first selective ingredient in this agar is bile, which inhibits the growth of Gram-positives other than enterococci and some streptococci species. The second selective ingredient is sodium azide. This chemical inhibits the growth of Gram-negatives.

The differential ingredient is esculin. If an organism can hydrolyze esculin in the presence of bile, the product esculetin is formed. Esculetin reacts with ferric citrate (in the medium), forming a phenolic iron complex which turns the entire slant dark brown to black. The tube on the far right was inoculated with E. faecalis (positive). The tube in the center was inoculated with a bilie esculin negative organism and the tube on the left was uninoculated.


The Relationship Between Language & Culture and the Implications for Language Teaching

The relationship between language and culture is deeply rooted. Language is used to maintain and convey culture and cultural ties. Different ideas stem from differing language use within one’s culture and the whole intertwining of these relationships start at one’s birth.

When an infant is born, it is not unlike any other infant born, in fact, quite similar. It is not until the child is exposed to their surroundings that they become individuals in and of their cultural group. This idea, which describes all people as similar at birth, has been around for thousands of years and was discussed by Confucius as recorded in the book by his followers, Analects (Xu, 1997). From birth, the child’s life, opinions, and language are shaped by what it comes in contact with. Brooks (1968) argues that physically and mentally everyone is the same, while the interactions between persons or groups vary widely from place to place. Patterns which emerge from these group behaviours and interactions will be approved of, or disapproved of. Behaviours which are acceptable will vary from location to location (Brooks, 1968) thus forming the basis of different cultures. It is from these differences that one’s view of the world is formed. Hantrais (1989) puts forth the idea that culture is the beliefs and practices governing the life of a society for which a particular language is the vehicle of expression. Therefore, everyone’s views are dependent on the culture which has influenced them, as well as being described using the language which has been shaped by that culture. The understanding of a culture and its people can be enhanced by the knowledge of their language. This brings us to an interesting point brought up by Emmitt and Pollock (1997), who argue that even though people are brought up under similar behavioural backgrounds or cultural situations but however speak different languages, their world view may be very different. As Sapir-Whorf argues, different thoughts are brought about by the use of different forms of language. One is limited by the language used to express one’s ideas. Different languages will create different limitations, therefore a people who share a culture but speak different languages, will have different world views. Still, language is rooted in culture and culture is reflected and passed on by language from one generation to the next (Emmitt & Pollock 1997).
From this, one can see that learning a new language involves the learning of a new culture (Allwright & Bailey 1991). Consequently, teachers of a language are also teachers of culture (Byram 1989).

The implications of language being completely entwined in culture, in regards for language teaching and language policy are far reaching. Language teachers must instruct their students on the cultural background of language usage, choose culturally appropriate teaching styles, and explore culturally based linguistic differences to promote understanding instead of misconceptions or prejudices. Language policy must be used to create awareness and understandings of cultural differences, and written to incorporate the cultural values of those being taught.

Implications for language teaching
Teachers must instruct their students on the cultural background of language usage. If one teaches language without teaching about the culture in which it operates, the students are learning empty or meaningless symbols or they may attach the incorrect meaning to what is being taught. The students, when using the learnt language, may use the language inappropriately or within the wrong cultural context, thus defeating the purpose of learning a language.

Conflict in teaching styles also stem from the relationship between language and culture. During the past decade, I have taught English in Taiwan and have observed a major difficulty in English instruction brought about by teachers and suffered by students. Western English teachers who teach in Taiwan bring along with them any or all of their teaching and learning experiences. To gain employment in Taiwan as an English teacher (legally), one must have received a Bachelor’s degree (Information for foreigners), thus, all instructors of English in Taiwan have, to some degree, an experience of learning in a higher educational setting. From this, they bring with them what they imagine to be appropriate teaching methodology. What is not generally understood, even seldom noticed is that while Taiwanese classes are conducted in a Chinese way, that is in a teacher centered learning environment, the native English teacher’s instruction is focused on student centered learning (Pennycook 1994). Pennycook (1994) continues by pointing out that student centered learning is unsuitable for Chinese students. The students may not know how to react to this different style of learning. A case in point, when at the beginning of my teaching career in Taiwan, I found it very easy to teach English, but very difficult to get the students to interact with me while I was teaching. Teaching was very easy because the students were well behaved and very attentive. The difficulties surfaced when trying to get the students to interact with me, their teacher. At the time, I did not realize that in Taiwan, it was culturally unacceptable for students to interact with their teacher. The Taiwanese students were trained to listen to what the teacher said, memorize it, and later regurgitate it during an exam. I was forced to change my method of teaching so that I was recognised as a “friend” rather than a teacher. The classroom setting had to be changed to a much less formal setting to coax out student interaction. As Murray (1982) pointed out, Chinese students will refuse to accept this “informal discussion” style of teaching. However, once the students were comfortable in their surroundings and didn’t associate it to a typical “Chinese” style class, they became uninhibited and freely conversed in English. The language classes taught using this style proved to be most beneficial to the students with an overall increase in the grade point average.

Because language is so closely entwined with culture, language teachers entering a different culture must respect their cultural values. As Englebert (2004) describes: “…to teach a foreign language is also to teach a foreign culture, and it is important to be sensitive to the fact that our students, our colleges, our administrators, and, if we live abroad, our neighbours, do not share all of our cultural paradigms.”

I have found teaching in Taiwan, the Chinese culture is not the one of individualism, as is mine, but focused on the family and its ties. The backwash from teaching using western culturally acceptable methods must be examined before proceeding as they may be inappropriate teaching methods, intentional or not, may cause the student embarrassment, or worse, to the entire students’ family. As Spence (1985) argues, success and failure in a Chinese cultural framework influences not just oneself but the whole family or group. Therefore, teachers must remember to respect the culture in which they are located.

Language teachers must realize that their understanding of something is prone to interpretation. The meaning is bound in cultural context. One must not only explain the meaning of the language used, but the cultural context in which it is placed as well. Often meanings are lost because of cultural boundaries which do not allow such ideas to persist. As Porter (1987) argues, misunderstandings between language educators often evolve because of such differing cultural roots, ideologies, and cultural boundaries which limit expression.

Language teachers must remember that people from different cultures learn things in different ways. For example, in China memorization is the most pronounced way to study a language which is very unlike western ideologies where the onus is placed on free speech as a tool for utilizing and remembering vocabulary and grammar sequences (Hui 2005). Prodromou (1988) argues that the way we teach reflects our attitudes to society in general and the individual`s place in society.
When a teacher introduces language teaching materials, such as books or handouts, they must understand that these will be viewed differently by students depending on their cultural views (Maley 1986). For instance, westerners see books as only pages which contain facts that are open to interpretation. This view is very dissimilar to Chinese students who think that books are the personification of all wisdom, knowledge and truth (Maley 1986).

One should not only compare, but contrast the cultural differences in language usage. Visualizing and understanding the differences between the two will enable the student to correctly judge the appropriate uses and causation of language idiosyncrasies. For instance, I have found, during my teaching in Taiwan, that it is necessary to contrast the different language usages, especially grammatical and idiom use in their cultural contexts for the students to fully understand why certain things in English are said. Most Taiwanese students learning English are first taught to say “Hello. How are you?” and “I am fine. Thank you, and you?” This is believed to be what one must say on the first and every occasion of meeting a westerner. If I asked a student “What’s new?” or “How is everything?” they would still answer “I am fine, thank you and you?” Students often asked me why westerners greet each other using different forms of speech which, when translated to Mandarin, didn’t make sense. This question was very difficult to answer, until I used an example based in Chinese culture to explain it to them. One example of this usage: In Chinese, one popular way to greet a person is to say (…phonetically using pinyin) “chr bao^ le ma?” This, loosely translated to English, would have an outcome similar to “Have you eaten?” or “Are you full?” This greeting was developed in ancient Chinese culture as there was a long history of famine. It was culturally (and possibly morally) significant to ask someone if they had eaten upon meeting. This showed care and consideration for those around you. Even now, people are more affluent but this piece of language remains constant and people still ask on meeting someone, if they have eaten. If someone in a western society was greeted with this, they would think you are crazy or that it is none of your business. The usage of cultural explanations for teaching languages has proved invaluable for my students’ understanding of the target language. It has enabled them to differentiate between appropriate and inappropriate circumstances of which to use English phrases and idioms that they have learnt. Valdes (1986) argues that not only similarities and contrasts in the native and target languages have been useful as teaching tools, but when the teacher understands cultural similarities and contrasts, and applies that knowledge to teaching practices, they too become advantageous learning tools.

Implications for language policy
Creators of second language teaching policies must be sensitive to the local or indigenous languages not to make them seem inferior to the target language. English language teaching has become a phenomenon in Southeast Asia, especially in Taiwan. Most Taiwanese universities require an English placement test as an entry requirement (Information for Foreigners Retrieved May 24, 2007). Foreigners (non-native Taiwanese) which are native English speaking students however, do not need to take a similar Chinese proficiency test, thus forwarding the ideology that the knowledge of English is superior to the Chinese counterpart and that to succeed in a globalized economy one must be able to speak English (Hu 2005). Such a reality shows that our world has entered the age of globalisation of the English language, in which most observers see a tendency toward homogeneity of values and norms others see an opportunity to rescue local identities (Stromquist & Monkman 2000, p 7). The implications for language policy makers are that policies must be formed which not only include but celebrate local languages. Policies must not degrade other languages by placing them on a level of lower importance. Policies should incorporate the learner’s first language, the usage, and complexities as a means to create better linguistic comprehension as well as cultural understanding.

Policies for language teaching must encompass and include cultural values from the societies from which the languages are derived as well as being taught. In other words, when making policies regarding language teaching, one must consider the cultural ideologies of all and every student, the teacher, as well as the culture in which the target language is being taught. Language teaching policies formed with the cultural characteristics of both teacher and student in mind will not be prone to make assumptions about the appropriateness of students’ behaviour based on the policy maker’s own cultural values (Englebert 2004) but will increase cultural awareness. The American Council on The Teaching of Foreign Languages has expounded on the importance of combining the teaching of culture into the language curriculum to enhance understanding and acceptance of differences between people, cultures and ideologies (Standards 1996).
One example where as policy makers did not recognize the importance of culture is outlined by Kim (2004), in which the Korean government had consulted American ESL instructional guidelines which stated that for students to become competent in English they must speak English outside of the classroom. The government on reviewing this policy requested that all Korean English language students use English outside of the classrooms to further enhance their language competency. What they failed to consider is that while in America, English is taught as a second language and speaking English was quite acceptable in all locations, that in Korea, English is taught as a foreign language and the vast majority of the Korean population do not converse with each other in English. Korean students speaking English outside of the classroom context were seen as show-offs. In a collectivistic culture, as is Korea, such displays of uniqueness are seen as a vice to be suppressed, not as a virtue (Kim 2004). Thus policy makers must not rely on the cultural views and policies of others, but incorporate the cultural views of the students as well as considering the culture where the teaching is taking place. Language teachers need to be informed about various teaching interaction-based methodologies, manipulate them and develop their own teaching methods compatible with the educational context to foster interaction between students (Kim 2004).

When creating policies, one must consider the cultural meanings of teaching materials used. The materials may have a far broader meaning or encompass far more (or less) than what one has considered. An example of this is when the school I worked for decided that I introduce a discussion topic on holidays with one of my classes. The school did not enlighten me as to the cultural significance of holidays or what the Chinese equivalent of the word entails. This problem, as described by Yule (1996), is that people have pre-existing schemata or knowledge structure in their memory of what constitutes certain ideas e.g. an apartment, a holiday, what are breakfast items. The culturally based schemata that the students had for holidays were considerably different than that of my own. Their ideology of a holiday was any day that was special, possibly where one did not have to go to school, a weekend, a birthday, or any other major happening. When I asked the students what their favourite holiday was, I received many replies, all of which were not what I was looking for. I proceeded to tell them that Christmas was a holiday. This however, was a bad example as Christmas is not a holiday in Taiwan. In addition, I did not consider that a Chinese definition of the English word ‘holiday’ has a very broad meaning, thus the students were correctly answering my question however in their own cultural context.

Finally, as this paper has shown, language and culture are intertwined to such an extent whereas one cannot survive without the other. It is impossible for one to teach language without teaching culture. The implications for language teaching and policy making are therefore vast and far reaching. As a teacher of language, one must be culturally aware, considerate of the students` culture, and inform students of cultural differences thus promoting understanding. Language policy must reflect both the target language culture as well as the students`, teacher`s, and administrative persons` culture thus avoiding any cultural misinterpretations.

Works Cited

Allwright D & Bailey KM (1991) Focus on the language classroom: an introduction to classroom research for language teachers. Cambridge: Cambridge University Press.

Brooks N (1986) Culture in the classroom. In JM Valdes (ed) Culture bound: bridging the cultural gap in language teaching. Cambridge: Cambridge University Press, pp 123–128.

Byram M (1989) Cultural studies in foreign language education. Clevedon: Multilingual Matters.

Emmitt M & Pollock J (1997) Language and learning: an introduction for teaching (2nded). Melbourne: Oxford University Press.

Englebert (2004) Character or Culture? An EFL Journal, 24(2), 37-41.
Hantrais L (1989) The undergraduate’s guide to studying languages. London: Centre for Information on Language Teaching and Research.

Hui Du (2005) False alarm or real warning? Implications for China of teaching English. Journal of Educational Enquiry, Vol. 6, (1), 90- 109. Information for foreigners (n.d.) Retrieved June 17, 2007 from
http://iff.immigration.gov.tw/front/residence.php

Kim J. (2004) Coping with Cultural Obstacles to Speaking English in the Korean Secondary School Context. Asian EFL Journal, Vol 6 Issue 3 Retrieved May 12, 2007 from http://www.asian-efl-
journal.com/september_04_ksj.php

Maley A (1986) XANADU – ‘A miracle of rare device’: the teaching of English in China. In JM Valdes (ed) Culture bound: bridging the cultural gap in language teaching. Cambridge: Cambridge University
Press, pp 102–111.

Murray DM (1982) The great walls of China. Today’s Education, vol 71, pp
Porter E (1987) Foreign involvement in China’s colleges and universities: a historical perspective. International Journal of Intercultural Relations, vol 11, no 4, pp 369–385.

Prodromou L (1988) English as cultural action. EFT Journal, vol 42, no 2, pp 73–83.

Murray DM (1982) The great walls of China. Today’s Education, vol 71, pp 55–58.

Spence JT (1985) Achievement American style: the rewards and cost of individualism. American Psychologist, vol 40, no 12, pp 1285–1295.

Stromquist NP & Monkman K (2000) Defining globalization and assessing its implications on knowledge and education. In NP Stromquist & K Monkman (eds) Globalization and education: integration and contestation across cultures. Lanham: Rowman & Littlefield, pp 3–2

Valdes JM (1986) Culture bound: bridging the cultural gap in language teaching. Cambridge: Cambridge
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Xu ZG (1997) Interpretation of Analects. Beijing: People’s Literature Press.

62 Comments

This article is very helpful. Thank you

Learners will not learn language separated from its cultural context.

Teachers should have an idea about the culture of the language that he /she taught to avoid misunderstanding as the language and culture are tightly connected.

Most people separate language from culture, but in fact we can not do this because we use language to express our culture and when we learn a language it is not enough to know the structure or the lexis, we need also as learners to be exposed to the culture by using the language, so we would know more about it.

It is clearly shown the mutual importance of language and culture , a good teacher bears in mind that teaching a language is not only transfering its lexical, phonological or structure systems but also, being aware of the impact of the culture on producing or reciving a language.

Any person can communicate easily by using the target language if he or she knows the specific features of the new culture.

It is obvious that the language and culture are strongly related to eachother. They are even noticed in our daily life , when ever we meet new people, they will notice our language and they will immediately ask whare are you from?. This article was very benificial.
The teacher should take into consideration , the different students culture in one classroom. And even plan a lesson upon these different cultures within.

This article was really helpful

I noticed that language is affected by culture. because cultures intetrfere each other which leads to producing new concepts of language.

I noticed that language is affected by culture. Especially because cultures interfered with each other which eventually led having new language.

Thank you for the useful tips. Language is interconnected with culture. We adapt our language to the culture we are exposed to. As teachers, we need to teach our students that each culture has its own characteristics. Students should be aware that they won’t find equivalents for each and everything they want.

knowing the distinctive relationship between language and culture helps teachers to be more creative,more skillful and able to solve many problems they may encounter.language teachers should understand and respect students’culture,it’s too necessary to attract their attention toward learning.

Thanks for the great article learning a new language means to learn anew culture too,and these tow are compined together introducing anew language within the culture make it much easy.

Culture is something influenced and impacted by the language whereas, language is formed by the culture of a society. Similarly, language is not only an expression or a means of communication, but a component of a culture that makes it unique and specific.

Our values and speech shapes our identity and personality. It not only does represent the individual identity, but represents the identity of where he/she belongs to.

Humans are born in the same way and experience the same stages of life. However, the difference is the environment in which each individual grows up and the accent which he/she becomes familiar to. This creates a specific identity of a certain values and speech that differs from person to person.

thanks for this useful article. Language is the official spokesman of culture, through it we learn about other countries cultures language and culture are very connected to each other.

Thank you for this interesting article which is smooth and easy to understand ,this let us think about the importance of knowing the culture of the country before learning it’s language to use it in appropriate way.

Culture and language both of them related to each other, we can’t separate them.If we know culture we could easily learn it’s language all babies when they born they are the same but language and culture give him or her the ID

Thank you for this sharing. I think language is a reflection of cultures. Everyone’s thoughts are shaped by his own culture and the the understanding of related culture helps in enhancing the knowledge of their language. So, teachers of a certain language should refer to the culture to understand some concepts than cannot be transmitted in a new culture.

Language and culture may consider one unit. Both of them are interconnected. This article was amazing and useful.

When you learn a new language, it not only involves learning its alphabet, the word arrangement and the rules of grammar, but also learning about the specific society’s customs and behavior. When learning or teaching a language, it is important that the culture where the language belongs be referenced, because language is very much ingrained in the culture.

Different language with one culture and the whole inter wining of these relationship start at one birth day.The understanding of a culture and its people can be enhanced by the knowledge of their language

In order to teach language ,you have to teach the related cultural things and makes a useful link between them

language and culture are two issues inextricably linked and tied to each other. so their impact on each other is nessary inevitable.

It’s very important to entwin language to culture since they’re deeply connected & affect each other. You , as a teacher, cannot teach a language apart from it’s language coz it’ll be meaningless and Ss won’t benefit the wanted outcomes.
Introducing the language with relating it to the culture makes the vocabs and phrases more comprehensive.

You can’t teach language without teaching culture. You have to link the second language with the culture to stimulate students.

Since thoughts differ because the use of different languages, when one want to learn a new language it is a must to learn about its culture to better understand the way how meanings are comprehended.

language and culture are very connected to each other, so language teacher should teach students culture of the source language to make sure that students will use the language in the right culture context. teacher should also pay attention to the way his students look at teaching process. He should also be aware to the culture of his students.

The phrase language is culture ad culture is language,so the relationship between them is very strong.In addition,when we learn language we learn culture and different cultures allow people learn in different ways.

Language and culture are both related to each other every child comes to life and learn the language by interacting with people around him.
Language shaped by the culture because we see that in the same country people use the same language but in differant ways and accents and they use some of the words differantly according to the place they live in.
If we want to learn any language we need to know or understand the culture and the way of thinking for these people who speak this language.

The implications of language being completely entwined in culture and Language policy must be used to create awareness and understandings of cultural differences, and written to incorporate the cultural values of those being taught.so,
Teachers must instruct their students on the cultural background of language usage and conflict in learning styles.

“Language is the culture and culture is the language” both developed together .

The more you know about culture the easier it is to get involved and learn new words.

Great article. I completely agree with the author, that our language shaped by our culture and teaching language means teaching culture. we can’t separate learning languages from their cultures because the relation between them is deeply rooted.

Thank you for this great content.
I agree with with you that language and culture they are associated together and if you are not that familiar to its culture you won’t be able to learn their language it helps us to onow more about it and gain more knowledge

language is usedto transmit values,laws, rituals and even the taboos. it affects the identy of people who live in the same place and create specific behaviours. also language the way we thinking, living and our style life.

This content is really helpful to enhance my skills of writing and understanding of text in this new study environment. Thanks alot to provide this readings

I have learnt many things when i switched from culture to English learning. Culturally the learning of my language has helped very much in the learning of English language

I am asking these questions because I want to show
you the best way to boost the pleasure of watching live sports.
The new bingo sites connected with real free bingo offers many top quality games.
While gaining knowledge through our own mistake is good, gaining knowledge through other people’s mistakes
will be brilliant.
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thanks for the great information…now I know a lot about the bond between language and culture.

Yes a wonderful and interesting article. I am a Dutch second language teacher and anthroplogist. And it would be excellent idea to integrate cultural awereness more into language training.

Many thanks for the inspiring insights in this article. I am currently doing my Phd research study at the Tech.Uni.Dresden-Germany, about the theme : “Enhancing Literacy and Cooperatives in the Informal Education Settings in Uganda”. There we have to learn English at school amidst a myriad of local languages, the two most widely used are Luganda and Swahili in my study area.I would like to receive and use this and other similar examples from Asia as research, teaching and training materials, in order to bring awareness for the need for appropriate language policy implications in Africa, beginning with Uganda.

Therefore, I kindly request for more information in this regard.
Secondly, I would like to be in contact with researchers and actors/activists within the African cultural context

Enlightening and at its best . Thanks for your compilation & direction

I find the article is easy to be understood. Thank you.

From a teachers standpoint, I might agree with some of the previous methods comments, but from a researchers standpoint doing a doctorate study on 2nd language in Korea, I like what you wrote. It will help me. Thank you.

I blog quite often and I seriously thank you for your content.

Your article has really peaked my interest. I’m going to take a note of your site and keep checking for new information about once per week.
I opted in for your RSS feed as well.

Thanks for your knowledge despite the fact that it was not properly punctuated and some errors in writing.

thanks for educative article.this article somehow touches my life..

I born and grown up in a society which is not my families type in culture and language. I learn their language and culture but not my families original culture as they were displaced from their original birth place.

2 years ago (after I am 25 yrs old),they relocate me with the whole family to their original birth place. this communities are my relatives in blood but not in culture and language. I cannot speak their language but my father and mother do.I couldn’t adapt their culture yet but my families do.

my parents wants me to marry one the lady from this communities to rebuild my culture and to bring my up coming children on their culture track.

how I can date someone whom we speak different language,culture etc…

If its not for my family,I would have been returned to the place I have grown up.

Thanks a lot. It really helped a lot.

A telling example of cultural differences is your use of the word learnt, a normal usage in the UK, but far less frequently in the US and Canada. It was the one clue which left me with the impression you were not a native born American, our colloquialisms can be very illustrative.

Thanks a lot. My other question is what is the relationship between language, culture and society?

Your article is a good one. As a masters student of language arts education in Nigeria, I found it so helpful. There is content and the message is clear. Thanks a lot.

thanks for your contribution my is how language affects culture

Thaks alot .it really helpfull piece of writing..very concise and to the point..I -as a second of English -found easy to digest..

language and culture are two issues inextricably interwoven and tied to each other. so their impact on each other is inevitable.

thanks.this will help me alot in my assignment.its really great.

thanks, it will help me a lots in my forth coming exam, my medium of exam is Hindi and i will translate it into Hindi.

Thanks for your guidance through this work of your’s. It is helpful for me asI am doing research on language and culture at JNU.
Regards,
Manisha Pal

your work was of great important.i’m a student teacher writting a project on the topic’METHODOLOGY OF ENGLISH LANGUAGE AND IT’S IMPLICATION’.i’ll welcome suggestions help tools from you.

It certainly could do with some editing, but it is provided free both by the author and the site after all. More importantly, I think comments on its content are far more constructive than the comments you have made

This is a poorly written, error-filled thesis: incomplete sentences, sloppy punctuation, occasional gibberish. It doesn’t speak well for the author or for TEFL.net. Examples: “When an infant is born, it is not unlike any other infant born, in fact, quite similar.” “The implications of language being completely entwined in culture, in regards for language teaching and language policy are far reaching.” “”… one must consider the cultural ideologies of all and every student, the teacher, as well as the culture in which the target language is being taught.” I’m astonished to find that the author is a native English-speaker.

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Identifying an Unknown Staphs, Strep, or Enteric

This lab should give you the background information and techniques you will need to successfully perform biochemical tests in order to identify unknown bacterial samples. The micro lab website, your textbook, the web and assorted books available in lab will be the reference materials necessary for you to successfully complete the next several weeks of lab work.

  • Each pair will receive one unknown organism to identify. You will conduct tests appropriate for your organism to determine genus and species identification.
  • Each pair may have to present information on the specific organism they identified including: test results, where that organism is part of the normal flora, when and where that organism becomes a pathogen, possible diseases the organism causes.
  • For each biochemical test you perform, make sure to record the following in your lab book:
    • What does a positive test result look like?
    • What is the biochemical basis of the test?

    Work Flow

    Staphs

    Staphylococcus species are normal flora widespread over the body surface. They are also important pathogens. Some of the most common diseases caused by Staphylococcus species include: impetigo, toxic shock syndrome, bacteremia, endocarditis, folliculitis furuncle (boils), and osteomyelitis (bone abscesses). Many species of Staphylococcus have the ability to form biofilms which can then colonize structures such as medical catheters, stents, heart valves, prostheses, shunts, and valves.

    The clinically significant species are generally separated into coagulase-positive staphs (S. aureus) and coagulase-negative (CoNS) staphs (S. epidermidis, S. haemolyticus, and S. saprophyticus).

    Streps

    Many members of the Streptococcus genus are normal flora to the mouth, nose, and throat. The genus Streptococcus is a complex group causing a wide range of diseases such as: rheumatic fever, impetigo, pharyngitis, laryngitis, toxic shock syndrome, scarlet fever, and endocarditis.
    Streptococci are often classified based on hemolysis which can be seen by their reaction on blood agar. Alpha hemolytic species produce alpha-hemolysin which reduces hemoglobin (red) to methemoglobin (green) causing a brownish or greenish zone around the colony. Beta hemolytic species produce a hemolysin that forms a clear zone around the colony, indicating complete lysis of red blood cells. Gamma hemolytic species are non-hemolytic, having no apparent effect on red blood cells.

    Enterics

    The Gram negative enterics are important both as natural flora in the intestinal tract and as pathogens of disease in the gastrointestinal tract and other sites. Four main families with numerous genera and species comprise the Gram negative enteric: Enterobacteriacea, Pseuodmonadaceae, Vibrionaceae, and Camplyobacteraceae. You will only be working with organisms from the first two families.

    Lab Procedure

    We have included the basic procedure for doing many common biochemical tests below. You will find more specific procedures for specific biochemical test on the following pages. More complete information on selective & differential media can be obtained by consulting the Difco manuals in lab. You will need to look up the individual test for a more detailed description, including the biochemical basis of each test.

    Biochemical Tests for Staphylococcus Organisms

    Table 1: Brief Description of Biochemical Tests for Staphylococcus Organisms.

    Test Brief Instructions Probable Results
    TSA General Maintenance Media for Staphs Determine macromorphology
    Gram Stain To confirm culture purity Staphs & Streps are Gram positive Enterics are Gram negative
    McFarland
    Standard
    Dilute your organism in a tube of sterile water to obtain a turbidity equivalent to a 0.5 McFarland test standard. Hold your diluted tube and the 0.5 McFarland test standard against the black-lined McFarland reference card to accurately rate the turbidity.
    Coagulase Add a loop-full or 0.5mL of a pure culture to 0.5mL rabbit plasma. Gently rotate tube to mix, do not shake. Incubate for 24 hours at 37°C. Presence of clot indicates S. aureus
    Novobiocin Antibiotic Disk Sensitivity Dilute colonies from a pure culture into sterile saline to a 0.5 McFarland standard. Swab half the surface of a blood agar plate. Place a novobiocin disk lightly onto the surface. Incubate for 24 hrs at 37°C. A zone of growth inhibition ≤16 mm in diameter in a coagulase(-) staph is indicative of S. saprophyticus. See probable results table 2 below.
    Hemolysis Streak the other half of the blood agar plate to check for hemolysis. Stab into the agar surface at the last part of your streak. Incubate 24 hrs in O2. Beta hemolysis is indicative of S. aureus. See probable results table 2 below.

    Table 2: Probable Results for Staphylococcus Organisms

    Staphylococcus aureus Staphylococcus epidermidis Staphylococcus haemolyticus Staphylococcus saprophyticus Staphylococcus xylosus
    Macromorphology Creamy/Tan Medium Creamy/Tan Pinpoint White Small Creamy/Tan Wavy Margin Yellow/Orange Medium
    FTM Facultative Anaerobe Facultative Anaerobe Facultative Anaerobe Facultative Anaerobe Facultative Anaerobe
    Motility Non Motile Non Motile Non Motile Non Motile Non Motile
    Catalase Positive Positive Positive Positive Positive
    Oxidase Negative Negative Negative Negative Negative
    Coagulase Positive Negative Negative Negative Negative
    Novobiocin Susceptible Susceptible Susceptible Resistant Resistant
    Hemolysis Alpha Prime or Beta Hemolysis Alpha or Alpha Prime Hemolysis Alpha Prime or Beta Hemolysis Alpha Hemolysis Alpha Hemolysis

    Hemolysis - Blood Agar

    Intended Use

    Blood agar is used to support the growth of fastidious organisms and to determine the type of hemolysis (destruction of red blood cell walls) an organism produces.

    Principle

    Blood agar is a rich medium that has been supplemented with fresh 5-10% blood. The hemolytic response can be dependent upon the type of blood. Sheep blood is commonly used, but some organisms require rabbit or bovine blood.

    Test Procedure

    1. Streak a plate of blood agar for isolation.
      • Optional: Do your last streak with a needle and poke into the agar. This usually gives clear, reliable zones of beta hemolysis and is especially important to see the effects of streptolysin O which is oxygen labile. See page 84 of the Difco/BBL Manual.
    2. Incubate the plates at 37°C for 24-48 hours. Strep organisms should be incubated in the CO2 incubator.
      • The plate will be a brownish red color after 48hours.

    Results

    You can differentiate four types of hemolysis by the appearance of the agar.

    • Beta hemolysis is indicated by a clear colorless zone surrounding the colonies. There has been total lysis of the red blood cells.
    • Alpha hemolysis is indicated by a small zone of greenish to brownish discoloration of the media. This is caused by the reduction of hemoglobin to methemoglobin and its subsequent diffusion into the surrounding medium.
    • Alpha prime hemolysis is indicated by a zone of complete hemolysis, surrounded by a zone of partial hemolysis, a pink halo. This pattern can be easier to see if you scrape off the colony.
    • Gamma hemolysis is indicated by no change in the media.

    Limitations

    • The patterns of hemolysis can vary with the incubation atmosphere and the type of blood in the media.
    • Some Staph organisms will only show hemolysis after they have been refrigerated following incubation.

    Coagulase Test

    Intended Use

    Differentiates Staphylococcus aureus from other Staphylococcus species.

    Principle

    The coagulase test detects the presence of free and bound staphylcoagulase. This enzyme is excreted extracellularly by human strains of Staph. aureus. The mechanism of action is unknown.

    Test Procedure

    1. Thaw a tube of 0.5 mL rabbit plasma.
    2. Inoculate a loop-full of organism into the tube. Chose a well isolated colony.
    3. Ideally you should incubate the tube at 35°C for 4 hours checking every 30 minutes for clot formation. We incubate them overnight and put them in the refrigerator until the next lab period with comparable results.
    4. Check for clot formation.
    5. Dispose of the tube in the biohazard container.

    Results

    The formation of a clot in the bottom of the tube is considered a positive result. The clot will not move as you tilt the tube. Unclotted plasma will flow in the tube.

    Limitations

    • Methicillin resistant Staph. aureus have reduced clumping factor.
    • Do not shake or agitate the tube as this could break up the clot.
    • Some staphylococci strains produce fibrolysin after prolonged incubation at 35°C that can break up the clot resulting in false negative. Incubate the tube overnight at room temperature if you do not get a clot in 4 hours.
    • Some other rarely encountered staph species are also coagulase positive by the tube method.

    Biochemical Tests for Streptococcus Organisms

    Table 3: Brief Description of Biochemical Tests for Streptococcus Organisms.

    Test Operating Instructions Probable Results
    BH General Maintenance Media for Streps Determine macromorphology
    Gram Stain To confirm culture purity Staphs & Streps are Gram positive Enterics are Gram negative
    McFarland Standard Dilute your organism in a tube of sterile water to obtain a turbidity equivalent to a 0.5 McFarland test standard. Hold your diluted tube and the 0.5 McFarland test standard against the black-lined McFarland reference card to accurately rate the turbidity.
    Optochin
    Bacitracin
    SXT
    Use your 0.5 McFarland standard to swab half the surface of a blood agar plate. Evenly place one of each disk on the swabbed agar surface. Any zone of inhibition around the Bacitracin disk is indicative of S. pyogenes. See probable results table 4 below.
    Hemolysis Streak the other half of the plate to check for hemolysis. Stab into the agar surface at the last part of your streak. Incubate for 24 hrs in CO2. Beta hemolysis is indicative of S. pyogenes and S. agalactiae (sometimes). See probable results table 4 below.
    Salt Tolerance Lightly inoculate broth. Loosely cap and incubate for 24-48 hours in CO2. Yellow color change indicative of Enterococcus faecalis. See probable results table 4 below.
    Bile Esculin Streak the surface of the slant. Leave the cap loose. Incubate for 24-48 hours in CO2. Blackening of the agar is indicative of S. bovis and S. faecalis. See probable results table 4 below.

    Table 4: Probable Results for Streptococcus Organisms

    Streptococcus agalactiae Streptococcus bovis Streptococcus faecalis Streptococcus mutans Streptococcus pyogenes
    Macromorphology Medium Pinpoint Medium Pinpoint Small
    FTM Facultative Anaerobe Facultative Anaerobe Facultative Anaerobe Facultative Anaerobe Facultative Anaerobe
    Motility Non Motile Non Motile Non Motile Non Motile Non Motile
    Catalase Negative Negative Negative Negative Negative
    Oxidase Negative Negative Negative Negative Negative
    Optochin Resistant Resistant Variable Resistant Resistant
    Bacitracin Variable Resistant Resistant Resistant Susceptible
    SXT Resistant Variable Variable Variable Resistant
    Hemolysis Gamma Hemolysis Alpha Hemolysis Alpha Hemolysis Gamma Hemolysis Beta Hemolysis
    Salt Tolerance Variable Negative Positive Negative Negative
    Bile Esculin Negative Variable Positive Positive Negative

    Bacitracin/SXT Sensitivity

    Intended Use

    Bacitracin differential disks are used to presumptively identify Group A, beta-hemolytic streptococci from other beta-hemolytic streptococci. The combination of SXT sensitivity increases the accuracy of the results.

    Principle

    Bacitracin is an antibiotic isolated from Bacillus subtilis. It inhibits cell wall synthesis mainly through inhibiting the biosynthesis of peptidoglycan. SXT inhibits folate metabolism which interferes with bacterial DNA synthesis. Group A, beta-hemolytic streptococci are more sensitive to bacitracin than other beta-hemolytic streptococci.

    Test Procedure

    The standard protocol has been modified for our lab.

    1. Using a loop, select 3-4 well isolated colonies, ideally from an 18-24 hour culture. Transfer to a small amount of sterile water.
      • Adjust the turbidity to 0.5 McFarland standard.
    2. Use the procedure outlined in antimicrobial susceptibility testing to swab the entire plate to obtain confluent growth.
    3. Visually divide the plate in thirds, place a bacitracin and SXT in their section of the plate. Using sterile forceps or a swab, lightly but firmly press the disks to the agar surface to adhere them.
      • Save the other section for the optochin disk.
    4. Invert the plates and incubate them for 18-24 hours at 35°C in 5-10% CO2.
    5. Incubate another 24 hours if the results are negative.

    Results

    • Any zone of inhibition around the disk is considered sensitive (S).
    • No zone of inhibition with growth up to the disk is considered resistance (R).

    This table is from MacFaddin, Biochemical Tests for Identification of Medical Bacteria.

    Bacitracin SXT Presumptive ID
    S R Group A b-streptococci
    R R Group B b-streptococci
    R S Not Group A or B b-streptococci
    S S Rule out Group A or B with serologic tests

    Limitations

    • Only beta-hemolytic streptococci should be tested.
    • While this test is accurate it is not highly specific. Other biochemical or serological tests are required for accurate identification.
    • The growth should be confluent. Too light of a growth could cause some non-group A streptococci to appear susceptible to bacitracin.

    Hemolysis - Blood Agar

    Intended Use

    Blood agar is used to support the growth of fastidious organisms and to determine the type of hemolysis (destruction of red blood cell walls) an organism produces.

    Principle

    Blood agar is a rich medium that has been supplemented with fresh 5-10% blood. The hemolytic response can be dependent upon the type of blood. Sheep blood is commonly used, but some organisms require rabbit or bovine blood.

    Test Procedure

    1. Streak a plate of blood agar for isolation.
      • Optional: Do your last streak with a needle and poke into the agar. This usually gives clear, reliable zones of beta hemolysis and is especially important to see the effects of streptolysin O which is oxygen labile. See page 84 of the Difco/BBL Manual.
    2. Incubate the plates at 37°C for 24-48 hours. Strep organisms should be incubated in the CO2 incubator.
      • The plate will be a brownish red color after 48hours.

    Results

    You can differentiate four types of hemolysis by the appearance of the agar.

    • Beta hemolysis is indicated by a clear colorless zone surrounding the colonies. There has been total lysis of the red blood cells.
    • Alpha hemolysis is indicated by a small zone of greenish to brownish discoloration of the media. This is caused by the reduction of hemoglobin to methemoglobin and its subsequent diffusion into the surrounding medium.
    • Alpha prime hemolysis is indicated by a zone of complete hemolysis, surrounded by a zone of partial hemolysis, a pink halo. This pattern can be easier to see if you scrape off the colony.
    • Gamma hemolysis is indicated by no change in the media.

    Limitations

    • The patterns of hemolysis can vary with the incubation atmosphere and the type of blood in the media.
    • Some Staph organisms will only show hemolysis after they have been refrigerated following incubation.

    Salt Tolerance Broth

    Intended Use

    Salt tolerance broth is intended to differentiate non-beta-hemolytic strains of streptococci.

    Principle of Use

    Brain Heart Infusion (BHI) broth is supplemented with 6.5% sodium chloride and bromcresol purple as a pH indicator. The indicator is included to make reading the test results easier. The broth also includes dextrose. The fermentation of dextrose (glucose) results in the production of acid. This changes the pH of the media causing the media to turn from purple to yellow.

    Test Procedure

    1. Select no more than 2-3 colonies (preferably from an overnight culture) to inoculate a tube of salt tolerance broth.
      • It is important to lightly inoculate the tube otherwise you may get a false positive.
    2. Loosen the cap and incubate aerobically for 24 hours at 37°C.
    3. Continue incubation up to 72 hours if you get a negative result at 24 hours.

    Results

    A positive reaction is indicated by obvious turbidity in the media with or without a color change. A negative result is indicated by no growth after 72 hours. Enterococcus spp. typically changes the media color within 24 hours.

    Limitations

    • Many staphylococci can grow in media containing 10% salt. Mannitol salt agar has 7.5% salt.
    • Salt tolerance media was intended to differentiate catalase negative gram-positive cocci. Be sure to perform a catalase test before you proceed with the salt tolerance broth test.
    • Other species of catalase negative gram-positive organisms can grow in this media.

    Biochemical Tests for Enteric Organisms

    Table 5: Brief Description of Biochemical Tests for Enteric Organisms.

    Test Brief Instructions Probable Results
    TSA General Maintenance Media for Staphs Determine macromorphology
    Gram Stain To confirm culture purity Staphs are Gram positive
    McFarland Standard Dilute your organism in a tube of sterile water to obtain a turbidity equivalent to a 0.5 McFarland test standard. Hold your diluted tube and the 0.5 McFarland test standard against the black-lined McFarland reference card to accurately rate the turbidity.
    Mac Streak for isolation. Incubate 24-48 hrs at 37°C. See probable results table below.
    EMB Streak for isolation. Incubate 24-48 hrs at 37°C. See probable results table below.
    Citrate Streak surface only. Incubate loosely-capped 24-48hrs at 37°C. See probable results table below.
    TSI With a needle pick the center of a well isolated colony. Stab the center of the tube to within 3-5 mm of the bottom. Withdraw the needle and lightly streak the surface of the slant. Incubate for 24 hrs at 37°C. See probable results table below.
    Urea Heavily inoculate a tube of urea broth. Shake tube to distribute organisms. Incubate for 24-48 hrs at 37°C.
    Escherichia coli Klebsiella pneumoniae Proteus vulgaris Pseudomonas aeruginosa Salmonella typhimurium Shigella flexneri
    Macromorphology Creamy/Tan Medium Mucoid/Tan Medium Translucent Diffusible Translucent Diffusible Creamy/Tan Medium Creamy/Tan Medium
    FTM Facultative Anaerobe Facultative Anaerobe Facultative Anaerobe Strict Aerobe Facultative Anaerobe Facultative Anaerobe
    Motility Motile Non Motile Motile Motile Motile Non Motile
    Catalase Positive Positive Positive Positive Positive Positive
    Oxidase Negative Negative Negative Positive Negative Negative
    Mac Pink/Purple w/ precipitate Purple/Yellow w/ precipitate Colorless Yellow Media Colorless Yellow Media Colorless Yellow Media Colorless Yellow Media
    EMB Black w/Green Metallic Sheen Purple maybe Green Metallic Sheen Colorless or Pink Colorless or Pink Colorless or Pink Colorless or Pink
    Citrate Negative Variable Negative Positive Positive Negative
    TSI Yellow Slant
    Yellow Butt Gas
    Yellow Slant
    Yellow Butt Gas
    Yellow Slant
    Yellow Butt Gas, H2S
    Unchanged Slant & Butt Red Slant
    Yellow Butt Gas, H2S
    Unchanged Slant
    Yellow Butt
    Urea Negative Variable Positive Negative Negative Negative

    Simmons Citrate Agar Slant

    Simmons Citrate Agar Slant

    Principle

    Used for the differentiation and identification of Enterobacteriaceae on the basis of citrate utilization, citrate being the sole carbon source.

    Purpose

    Colonies capable of utilizing citrate as a carbon source produce a local increase in pH, changing the color of the medium from green to blue. Only citrate positive organisms will grow on this medium.

    Test Procedure

    1. Inoculate the organism directly onto the surface of a Citrate slant.
    2. Incubate aerobically at 35-37°C.
    3. Examine for growth and color change after 18-24 hours of incubation.

    Interpretations

    Good growth with the medium color turning blue indicative of Enterobacter aerogenes and Salmonella choleraesuis.

    Eosin Methylene Blue (EMB) Agar

    Eosin Methylene Blue (EMB) Agar

    Principle

    A differential plating medium for the detection & isolation of the gram-negative enteric bacteria.


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    How to Write Microbiology Unknown Lab Report | Microbiology Lab Paper


    In the past, it has been vital to distinguish the identities of microorganisms in the world. Knowing their identity has aided in diagnosing numerous diseases and has discovered the most beneficial treatment. The purpose of this study was to identify a Gram positive and a Gram-negative bacterium from a mixed culture. The methods that were previously studied and practiced in the Microbiology laboratory class were applied in order to identity two unknown bacterium.

    The lab instructor gave out a test tube labeled number 118, which consisted of two unknown bacteria, one Gram negative and one Gram positive. Sterile techniques were followed while performing precise instructions as stated in the referenced Laboratory Manual.

    The first procedure performed to isolate a pure culture from the mixture in the test tube onto a solid media. A sterile inoculating loop collected bacteria from the test tube with the unknown, and streaked a series of zigzag lines along two nutrient agar plates, using the Quadrant Streak Method. These plates were incubated for two days to allow the bacteria to grow. Both plates were studied, noting their characteristics, which were recorded in a journal. One distinct colony grew and a Gram stain was performed on the isolated colony. The Gram stain procedure was carefully followed according to the referred Laboratory Manual. Gram-negative rod shaped bacteria were identified using the microscope. The glass slide and nutrient agar plate were labeled Gram negative and were then stored in the refrigerator. Gram-positive bacteria did not grow. After determining the Gram-negative reaction, specific tests were performed.

    In order to identify the Gram-positive bacteria, a sample from the original test tube was streaked on a Mannitol Salt Agar plate and placed in the incubator at 37 Degrees Celsius. There was only one type of bacteria that grew. This was isolated and a Gram stain was performed. Both of the plates were labeled and stored in the refrigerator. Gram-positive cocci shaped bacteria were identified using the microscope. Several biochemical tests were chosen based on the identification table which was given by the lab instructor. These tests and results were recorded on the flow chart and the tables on the following pages for the Gram-negative and Gram-positive bacteria.

    Table one and two list the tests, purposes, reagents, observations and results.

    All of the following tests were performed on these unknowns:

    Unknown number 118 was streaked on a nutrient agar plate. A Gram stain was performed. It was determined that it was a Gram negative rod. Gram positive did not grow. In order to identify the Gram positive bacteria, a sample from the original test tube was streaked on an MSA plate. A Gram stain was performed which identified Gram positive cocci. Table 1 and Table 2 list all of the biochemical tests, purposes, reagents, observations and results. The results are also displayed in a flowchart.

    TABLE 1. Gram Negative (-) Tests

    To determine the gram reaction of the organism

    Crystal violet, Iodine, Decolorizer, Safranin

    To determine if organism is able to utilize citrate as carbon source

    Color change from green to blue

    To determine fermentation of galactose

    Negative galactose fermenter

    To determine if it ferments mannitol

    Negative mannitol fermenter

    To determine if it hydrolyzes gelatin

    It turned to liquid after refrigeration

    To determine if it ferments mannitol

    Medium changed from red to yellow

    Positive Mannitol fermenter

    To determine the gram reaction of the organism

    Crystal violet, Iodine, Decolorizer, Safranin

    To determine if urease hydrolyzes urea

    To determine if catalase is present

    The result of the tests for Gram negative led to the identification of Pseudomonas aeruginosa. A Gram stain discovered that the bacteria were rod shaped. A Simmons Citrate test was performed and the positive result narrowed it down to three bacteria. After a Gelatin and a Galactose test were performed, the only bacterium that remained was Pseudomonas aeruginosa. A negative result on a MSA plate verified this result. This was the correct identification because all of the other Gram negative were eliminated. There were no problems encountered in finding this conclusion.

    The result of the tests for Gram positive led to the identification of Staphylococcus aureus. A sample from the unknown bacteria was streaked on a MSA plate. A Gram stain was performed which verified Gram-positive cocci. This was a positive result for mannitol fermentation which narrowed it down to two bacteria. A negative urea test was performed, which also narrowed it down to the same two bacteria. A positive catalase test verified that the bacteria in the unknown would have to be S. aureus. This was the correct identification because all of the tests performed, identified S. aureus as the unknown Gram positive bacterium. The only problem I encountered was during the isolation streak, Gram positive could not be isolated on a nutrient agar plate. However, it did grow on a MSA plate and was isolated on a nutrient agar plate.

    S. aureus is a bacterium that is frequently found in the respiratory tract and on the skin. It is a common cause of skin infections, diseases and food poisoning, and is not always pathogenic (Tolan, 2011). Sometimes, disease-associated strains produce toxins which promote serious infections in the body. These toxins have proteins that activate antibodies which causes resistance. This emergence of resistance has led to MRSA (Methicillin Resistant S. aureus), and is a worldwide problem.


    Watch the video: Gram Staining Procedure Animation Microbiology - Principle, Procedure, Interpretation (January 2022).