Question

1. Biofilms are important characteristics of some bacteria. What are the stages for biofilms formation? Explain the importance of biofilms in the survival of such microorganisms in certain environments.

2. Why are infections caused by eukaryotic parasites harder to treat than those caused by prokaryotes? Explain and give examples. What is the most effective method to treat infections with Cestodes (tape-worms)?  why?

3. If a new bacterial species has been discovered, what are the steps that the researchers would have gone through to confirm its identity?

4. Plasmids are genetic elements found in bacterial cells. What are their main characteristics? Discuss the role of plasmids in bacterial infections and survival.

5. Some bacterial enzymes are essential for virulence. Explain the stages needed to establish microbial infections. Classify bacterial toxins. Provide two examples and describe their mechanism of action on mammalian cells.

Answer 1

Biofilm formation steps :- 1.bacterial attachment to a surface 2. Microcolony formation 3.Biofilm maturation 4. Detachment(dispersal) of bacteria which may colonize in new area.

Importance of Biofilm - Micro-organism attach to surfaces and develop biofilm.Each micro-organism surviving under extreme condition exhibits its specific resistance towards unfavorable situation.Aggregate microbial cells embedded in a self-produced matrix of extracellular polymeric substances.Biofilms are recalcitrant to extreme environments and can protect micro-organism from UV radiation,extreme temperature,extreme pH,high salinity,high pressure,poor nutrients and antibiotics.

Infection caused by eukaryotic cells are difficult to treat.Because our human cells are also eukaryotic cell and they have similar physiological pathways.So its difficult for antimicobial drugs to selectively target the pathogens.On the otherhand when we get infected by prokaryotic like bacteria Dr. provide antibiotic and antibiotic acts on different component of cell wall etc. of bacteria.

Oral medication for tapeworm infection including :Praziquantel or niclosamide,Albenadazole,Nitazoxanide etc.Becoz egg of tapeworm hatch and maigrate in the organism intestinal wall and hematogenously to the muscle and forming cysterci and infection goes sometimes in central nervous system.

New molecular technology in genomics and proteomics is shifting traditional techniqques for bacterial classification,identification and characterization methods based on the elucidation of specific gene sequences or molecular components of cell.By the Gene amplification and sequencing methods researcher can identify the new strain of bacteria.

Plasmid is small circular ds-DNA molecule(genetic element) in bacteria.They have self replication and genetic transfer property.They carry genes that benefits the survival of the organism and confer selective advantage such as antibiotic resistance.

Classification of Bacterial toxin