BSC 310 Lecture Notes - Lecture 52: Membrane Technology, Indicator Organism, Complementary Dna

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silvercicada472

12 Jul 2018

School

University of Alabama

Department

BSC

Course

BSC 310

Professor

Julie Olson

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Document Summary

Various water quality tests are available to detect the number and types of microorganisms in waters and assist communities in keeping the microbial content of water supplies at a low level. These tests vary from the more sophisticated tests to the standard procedures that have been used for decades. Among the most sophisticated tests for water bacteriology are those that employ gene probes. Gene probes are fragments of dna that seek out and combine with complementary dna fragments. Often the test is designed to test for the presence of escherichia coli in water. This gram-negative rod, usually found in the human intestine, is used as an indicator organism. If it is present, then it is likely that the water has been contaminated with human feces. To use a gene probe test for e. coli in water, the water is treated to disrupt any bacteria present and release their nucleic acid.

Related Questions

Case Study:

Bacteria are everywhereâon our skin, in our food, suspended in our drinking water. Although the
microbial majority is benign, a few bacterial species can make us sick. To safeguard against food- and
water-borne disease, microbiologists routinely screen our drinking water for bacterial pathogens.
Animal feces contain coliform bacteria, microorganisms that inhabit the intestines of warm-blooded
animals. Many coliform bacteria are also found on plants and in soil and water. Coliform bacteria are
not pathogens themselves, but their presence indicates the possibility of finding pathogens. In contrast,
fecal coliform bacteria such as Escherichia coli are found in feces, and their presence in drinking water
indicates fecal contamination. E. coli can also be a pathogen itself, so if E. coli is found in drinking
water there is a good chance that other pathogens are present, too.1
To detect E. coli and other coliform bacteria, microbiologists filter water samples and place the filter in
a Petri dish containing growth medium such as Endo agar. Microorganisms from the water grow and
form colonies, giving an estimate of the number of bacteria in each milliliter of water.
While E. coli forms colored, shiny colonies on Endo agar, other coliforms grow as white or clear
colonies.

Dark colonies = E. coli
White/clear colonies = coliform bacteria
White + Dark colonies = total coliform
bacteria.

The guidelines of maximum allowable limits for total coliforms in drinking and recreational waters vary
by state. Representative limits appear in the table below.2, 3, 4

Table 1. Maximum allowable limits of fecal coliform bacteria
(cells/100 ml)

	Total Coliforms	E. Coli
Drinking Water	0	0
Recreational Waters	400	235

Questions
1. Why would we want to count the number of fecal coliforms in a water sample?
2. Do 400 coliforms per 100 milliliters strike you as very many?
3. How many other types of bacteria might be present in a normal water sample?
4. What problems might Mary encounter when she uses these techniques in Antarctica?

True or False????? HELP

1. In the field of epidemiology, increased prevalence of a disease in a population is the universal signal that disease control and treatment are not effective.

2. Cytoplasmic membranes of prokaryotes typically contain more proteins than cytoplasmic membranes of eukaryotes microorganisms.
3. Sanger (or dideoxy) DNA sequencing produces relatively short DNA sequence data, but is by far the least expensive DNA sequencing method currently available.
4. The (italicizes) abbreviation lac Z refers explicitly to the beta galactosidase protein/ enzyme.
5. Archaeal pathogens have been linked to some of the most virulent infectious diseases. 6. A bacterial mutant that is unable to make an amino acid required for growth (relative to its wild-type strain is termed an auxotroph.
7. When counting plaques to enumerate phage particles (as in the BIOL2026 Laboratory), the plaque represents lacK, not presence, of bacterial growth.
8. Because of competition with plant roots for nutrients, microbial numbers in the rhizosphere are typically much lower than in surrounding bulk soil.
9. Chemolithoautotrophy is the strategy that facilitates the existence of biological communities deep beneath the earthâs surface and near hydrothermal vents.

10. In a primary treatment (1 Â°) system of a municipal sewage/ wastewater treatment plant, the main goal is to remove ammonium (NH4+) using specific bacterial enrichment cultures.
11. The small intestine in human is the main site of microbial breakdown of partially digested food.
12. Root nodules of legumes contain nitrogen fixing bacteria.
13. Anoxygenic photosynthesis involves using/ removing electrons from H2O.
14. Algae and Cyanobacteria utilize generally the same two-photosystem biochemical mechanisms in the light- reaction of photosynthesis.
15. In bacteria, the only known reason proton motive force is generated is to power ATP synthase in cellular respiration/ oxidative phosphorylation.
16. Anaerobic respiration is only carried out by prokaryotes, however fermentation can be carried out by both prokaryote and eukaryal microorganism.

17. The general structure and biochemical âmotorsâ of flagella are similar between Bacteria and eukaryotic cells, but fundamentally different in the Archaea.
18. Antibiotic resistance genes appeared in microbes (for the first time ever) only after human .. producing and releasing massive amounts of antibiotics to the environment.
19. Experiment by Esther Lederberg, and then later by Luria and Delbruck (that won them a Nobel prize), illustrated that genetic mutations in bacteria arose in the absence of selective pressures, rather than in response to selection.
20. Quaternary sensing is a mechanism used by bacteria to sense other bacteria and regulate gene expression accordingly (e.g. In the case of expressing the liac operon or initiating EPS production in biofilms).

BSC 310 Lecture Notes - Lecture 52: Membrane Technology, Indicator Organism, Complementary Dna

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