How did people identify different bacterial strains before the PCR? Thanks?
116081
OK.  I've searched all of my micro stuff and I can't find mention of a PCR anywhere.  You'd figure someone who could answer this question would know what a PCR was, but not this someone.\n\nAll I can say is that for years people relied on bacterial morphology (Spherical, Rods, Curved, Clusters, Chains, etc. . .), grams stain characteristics (+ or -), colony morphology, atmospheric growing conditions (O2, no O2, increased CO2), nutritional requirements, and biochemical tests (Peroxidase, Indole, Oxidase) to differentiate different species of bacteria from each other.\n\nI hope this is what you're looking for.
671418
PCR is a technique in which a specific stretch of DNA is amplfied greatly (a billion-fold or more).  Briefly, two small stretches of cDNA are designes that will bind to a stretch of DNA-almost like bookends. Then a Taq polymerase is added, which produces a complete cDNA starting from each primer.  Then the solution is heated, and the strands melt apart, then it's cooled, new primers bind (now there are twice as many stretches of that DNA) and the reaction is run again- Each time the reaction is performed, it doubles the amount of that specific DNA strand.  "Taq" polymerase is special in that it comes from a bacteria that lives in extremely high temperatures, so the melting phase of the reaction doesn't denature it.
928716
1.What bacteria are we talking about (E.coli? Which strain?)\n2.There is no such standard solution for any type of bacteria.\n3.Why on earth would you need such a dilution? \n4.What type of facilites do you have access to (You can isolate single cells by FACs provided you have a proper marker and this expensive equipment)
284461
I dated a guy who ran one.  He had his masters in microbiology and was in a doctorate program for something else....of course I can't remember now.  Sorry!!
224406
There are many different tests you could so on a culture to determine the type of bacteria. The main tests that you could do to find out a general idea of what Genus of bacteria you have would be things like a Gram stain, Catalase test, Oxidase test, O/F Fermenation test, growing the culture on different mediums, a motility test. Once you have done these tests there are then other tests which are more specific to one group of bacteria to give you an exact type of bacteria.
725203
I can't remeber off the top of my head but there is a wonderful book out there called Bergey’s Manual of Determinative Bacteriology 9th Edition that should be able to answer this question for you.
847518
Malonate- used for differentiation Enterobacter from E. coli\nTryptone- used to differentiate based on indole\nKCN broth- differentiates betweeen organisms based on their ability to grow in presence of cyanide\nNutrient gelatin- detects gelatin liquefactation by microbes\nOF glucose broth- differential and enriched\nDnase agar- differential (DNA degradation)\nOrnithine decarboxylase- differential for Enterobacteriaceae
474656
If you are talking about bacteria such as E Coli, you need to demonstrate that the markers are close to each other. To do that you need to do mating involving the F factor and demonstrate that the linked genes transfere near to each other.  This was done in classical expts in the 40s and 50s.
702124
You can find practical information from Qiagen website if you use their kits which are quite popular these days.  \n\nIt depends on which methods you use for isolation.  The alkali lysis (see link below) was commonly used to rupture bacteria.  Plasmid DNA (smaller in size and more soluble) is separated from baterial genomic DNA (larger and less soluble).  The plasmid DNA is then separate from proteins by phenol extraction where the proteins are removed to the phenol phase while plasmid DNA stays in the aquous phase.  The plasmid DNA is then precipated with ethanol to complete the purification.\n\nQiagen's kit and others overcome the use of phenol (which is toxic and smelly) by using a solid phase that bind DNA to seperate the contaminating proteins.  The DNA is later eluted from the solid phase to complete the purification.\n\nHere are additional links:\nhttp://biotech.biology.arizona.edu/labs/DNA_isolation_plasmid.html\nThe concept of alkali lysis method of plasmid DNA isolation is shown here:\nhttp://a32.lehman.cuny.edu/molbio_course/plasmid_protocol.htm
311249
Staphylococcus aureus is positive (clearing in the green agar) and Staphylococcus epidermidis is negative for the DNAse test.\n\nThose are the only one's I know about.
891338
In terms of how many restriction endonucleases there are "in the world", the answer could theoretically be in the millions.  Different strains of the same bacterial species can make different RE, so you can imagine the potential for variety in nature.\n\nAs for commercially available: new england biolabs sells about 230 different enzymes.\n\nAs for what's commonly used, it depends on the lab and the target organism.  The lab I got my PhD in, we worked with a low gc bacteria, and we used very different enzymes than we use in my current lab, working with a high gc bacteria.  In either case, we used 20-30 different enzymes.
980867
A. Antibiotics, antimicrobials.\n\nWhy are you testing us? Are you taking a test and cheating, perhaps?
469700
there are lots of ways to test water.  plating a water sample on EMB or MacConkeys agar will show if bacteria present are enteric bacteria.  if the sample has very few bacteria present you may have to filter a larger volume through a sterile 0.2 micron filter to collect enough bacteria to examine.
1177839
it used to be isolate the pathogen from an infected host and use it to infect a healthy animal, but i believe they are now using the third choice more because the second choice doesn't always work.  so i would say isolate bacterial/viral proteins by electrophoresis.
460908
human don't have plasmid. but if you're asking how to test a bacterium for human growth hormone (hgh) recombination into its plasmid, you can perform is PCR test for the HGH mRNA. that should be the most direct proof.\nor you can do a DNA sequencing, but that takes longer.
57968
If you are trained in microbiology you can tell by eye.  Plate out the bacteria (for single colonies) onto a universal media that is suitable for your target bacteria,  ie CLED, Maconkeys, Blood, Chocolate.  Incubate until there is a growth (usually 24hrs at 37 degreees celcsius is aerobic).  Look at the plate, are the colonies uniform in appearence.\n\nIf you are using liquid culture youu could use microscopy before plating out.  Either a gram stain or a direct (wet prep). This would let you know if you had all gram positives or all gram negatives or all rods or all  cocci or a mixture.  You would still have to plate out to make sure only one colony type grows.
981080
your teacher needs to work bettering his/her questions. Or you need to re-phrase the questions so their is more detail.\n\nI was given a similar question on a take home exam, but I think it contained some more information, so I actually learned something.\n\nWith the information given, the one thing you can find out about this plasmid is what gene it posseses that allows its antibiotic resistance.  \n\nYou would do this by plating out the plasmid on agar plates that contain different antibiotics i.e. kanamycin, ampicillin.\n\nYou can pick the colonies that grow, and test for the "glo" gene.  This would verify the presence of the antimicrobial gene from which the colony was picked from.\n\nIn other words, the colony which has the "glo" gene also contains the gene resistant to the antimicrobial agent it was on  grown on.\n\n\nI hope this helps.  Pass on the good Karma!