Microorganisms And Immunity: Characteristics, Culture, Antibiotics, Transmission, Immunity And Genetic Screening

Characteristics of viruses, bacteria, fungi, and protoctista

Part 1.

Complete a table that describes the characteristics of viruses, bacteria, fungi and protoctista.

Explain the conditions necessary for the successful culture of bacteria in laboratory and the safety precautions taken when using aseptic techniques.

Explain the role of antibiotics in controlling bacterial disease. Include detail of how they prevent the growth of bacteria, and factors that make antibiotics less effective, including resistance.

Explain the method of transmission and treatment of

A) One bacterial disease

B) One viral disease

C) One parasitic disease.

Part 2.

Describe natural, artificial, active and passive immunity.

Explain the role(s) of T and B cells in providing immunity. This could be in an annotated diagram.

Name a vaccine and explain how vaccinations produce immunity. Analyse data about the vaccination, including the numbers of people immunised and any impact it has had on the number of reported incidents of that disease since it has been used.

Part 3.

Complete a table that outlines three different types of genetic screening and the pros and cons of each.

Complete a flow chart to show the stages of insulin production using recombinant DNA.

Give an overview of the moral and ethical issues raised by DNA recombinant technology.

Learning outcome Assessment

criteria First submission Re-submission Achieved

1. Understand the role of micro-organisms in causing disease. 1.1. Compare the characteristics of viruses, bacteria and protoctista.

1.2. Explain the conditions necessary for the successful culture of bacteria.

1.3. Explain the role of antibiotics in controlling bacterial disease.

1.4. Explain the method of transmission and treatment of

a) One bacterial disease

b) One viral disease

c) One parasitic disease.

2.1. Explain the processes involved in the development of immunity.

2.2. Compare the actions of B cells with those of T cells in fighting infection.

2.3. Evaluate the role of vaccination in controlling disease.

3. Understand the application of DNA technologies to the diagnosis and treatment of disease.

3.1. Describe the process of genetic screening.

3.2. Describe the process of gene cloning into vectors and explain its use in the production of insulin.

3.3. Discuss the moral and ethical issues raised by DNA recombinant technology.   

Virus	Bacteria	Fungi ta	protoctista
Not living in environment, reproduce within host	Single celled with spherical, rod or thread like	Multicellular, heterotrophic organism	Single celled or multicellular
Does not respire	Prokaryotic, have cell wall, cell membrane and DNA as genetic material and does not have cell organelles (Abbas, Lichtman & Pillai, 2012)	Eukaryotic, have cell membrane and defined nucleus	Eukaryotic, contains nucleus and other smaller organelles, genetic material is packed in envelop
Have only genetic material RNA/DNA	Reproduce via binary fission	Can reproduce sexually or asexually	Reproduce via binary fission, asexual reproduction
Eg. HIV, Hepatitis B	Eg. E. coli, Streptococcus sp.	Eg. penicillin	Eg. Plasmodium falciparum

A growth medium with necessary nutrients is the primary requirement of bacterial culture. Usually agar gel is used, as it contains all things required by bacteria. Commercially produced media with all nutrients are used in the laboratories along with sterile water. Some organisms have special needs which are met by adding additional nutrients in the medium prepared. Most of the organism requires moderate conditions for grow including moderate temperature, 37ºC, neutral pH, around 7 and oxygen concentration in the case of aerobic organisms (Asthagiri & Arkin, 2012).

Conditions necessary for bacterial culture in laboratory and safety precautions taken

Safety precaution include washing hands, sterilizing with alcohol after using pathogenic culture, disinfecting work area with alcohol after use, working with culture under UV cabinet, using gloves, using micropipettes, clear labeling and discarding waste materials after disinfecting it (Talaro & Chess, 2012).

Figure: Bacterial culture

(Source: Jain, 2012)

Antibiotics are the secondary metabolites of microorganisms which either kill bacteria or block their growth while present in the culture. The bacteriostatic organisms usually blocks the growth of organism, withdrawal of antibiotic revive the function of the organism. In contrast, bactericidal antibiotic works by killing organism. They do not affect host cells (Jain, 2012).

A number of factors can hamper the function of bacteria. One of them is the bacterial resistance. The resistance toward an antibiotic can be transferred to bacteria by transferring ‘R’ plasmids.

Figure: Antibiotic controlling bacterial growth

(Source: Laskin, Sarialani & Gadd, 2012)

1. Bacterial disease

Campylobacter infection is caused by the Campylobacter sp.  bacteria via contaminated food. The route of transmission is oral in this case. It causes inflammatory dysentery, diarrhea to the patient, causing dehydration. Fluoroquinolone, tetracyclines are effective antibiotic treatment against the infection (Laskin, Sarialani & Gadd, 2012).

2. Viral disease

Influenza virus causes flu with runny nose and related symptoms. As it is an air borne virus, the route of transmission is nasal route. It can be treated via anti viral drug treatment, which also includes antibiotic usage.

3. Parasitic disease

Plasmodium falciparum is a parasite which uses two hosts in their life cycle. The parasite completes most part of its life cycle in anopheles mosquito’s salivary gland and transmitted to human body by bite of infected mosquito and causes malaria. Treatment includes administration of chloroquine, mefloquine (Talaro & Chess, 2012).

Natural immunity

Natural immunity refers to innate or non specific immunity which is raised by body after encountering the physical and cellular barrier of defense system.

Artificial immunity

Artificial immunity is induced by the exposure of the patient to a vaccine, substance containing the inactivated pathogen.

Active immunity

When a person is exposed to a live pathogen, the resulting natural immunity of body immune system against the pathogen is known as the active immunity (Male, 2012).

Passive immunity

Passive immunity is induced by the antibodies which are ready-made. The active humoral immunity when transferred to the antibodies administered outside of the body, the passive immunity is developed.

The T and B cells are the key players of adaptive or acquired immune system. After encountering any foreign particles, the T lymphocytes are the stimulator of adaptive and B cells are the stimulator of humoral immune system. B cells engulf the pathogens and present through MHC complex which is then bound by specific T cells and stimulates the differentiation of more T cells, on the other hand, secreted lymphokines influence differentiation of B cells into plasma and memory B cells. Plasma cells act in active immunity (Male, 2012).

Polio vaccine provides immunity against the Polio virus. Two kinds of vaccines are available in market. IPV is inactivated polio vaccine in which the organism is injected in an inactivated state, against which the antibody is generated in body. OPV is oral polio vaccine, in which the live vaccine is injected in attenuated state; the organism has lost the capability of infection. IPV has been reported to immunize 99% people after 3 doses and OPV has been reported to protect 95% individual after 3 doses (Stansfield et al., 2012).

Figure: Role of B and T cells in Immunity

(Source: Jain, 2012)

Forensic screening	Screening of genetic disease	Prenatal screening
Forensic screening is used for detecting criminal offenses or catastrophe victims and used for legal purposes. DNA foot printing is used in this case which uses DNA sequences from victim’s or accused person’s sample	Genetic screening  is done for detecting genetic mutation, RFLP, AFLP, SNP are used for diagnosing genetic disease	Prenatal testing is done for identifying any kind of genetic mutation in fetus.
It is beneficial as it helps to detect the actual offensive person and helps in legal work	It helps to identify genetic disorder which is beneficial if identified at first stage	Pros of this testing is getting awareness of any detrimental disease of fetus
Sometimes ethical issues raises regarding the forensic screening as it deals with personal information of suspect or victim (Jain, 2012)	Sometimes it raise ethical issue if the stem cell therapy is necessary	Sometimes it brings ethical issues, if the fetus is diagnosed to have genetic disorder, in that case the ethical concern is regarding the survival of fetus

Figure: Insulin production in RDT

(Source: Rajagopal, 2012)

The moral and ethical issues arise regarding the recombinant DNA technology arises while working with human genome. The modern techniques in RDT are capable of changing human characteristic at the gene level which is changing the nature’s decision. Changing human hereditary characteristic is an ethical issue, everyone would try to get the best characteristics and there would be issues regarding superiority, especially while working with stem cells. Thus human cloning has been banned (Jain, 2012). 

Reference List

Abbas, A., Lichtman, A., & Pillai, S. (2012). Cellular and molecular immunology. Philadelphia: Elsevier/Saunders.

Asthagiri, A. & Arkin, A. (2012). Methods in cell biology. Amsterdam: Elsevier/Academic Press.

Jain, M. (2012). Recombinant DNA techniques. Oxford: Alpha Science International.

Laskin, A., Sarialani, S., & Gadd, G. (2012). Advances in applied microbiology. Boston: Academic Press.

Male, D. (2012). Immunology. [Edinburgh]: Mosby Elsevier.

Rajagopal, K. (2012). Recombinant DNA technology and genetic engineering. New Delhi: Tata McGraw Hill Education Private Limited.

Stansfield, W., ColomeÃŒÂ, J., Cano, R., & Cullen, K. (2012). Molecular and cell biology. New York: McGraw-Hill.

Talaro, K. & Chess, B. (2012). Foundations in microbiology. New York: McGraw-Hill.