Microbes
43) Not all species of the same microbe are pathogens!
Strain is used to recognize genetic variants of the same species-usually have numbers after
species name...
-E. coli K-12
-E. coli B
Urgent fact: Motility cannot classify prokaryotes.
Bacterial classification based on:
– Morphology(shape, size, arrangement)
– Staining characteristics
– Bergey’s manual of Determinative Bacteriology
(biochemical reactions)
– 16S rRNA sequence
Fun fact #3: In Eukaryotes, organisms belonging to same species can sexually reproduce with each other.
In Prokaryotes, organisms belonging to same species share at least 70% DNA similarity and 97% 16S rRNA sequence similarity.
12*) When do we use electron microscope?
An electron microscope with 300,000x magnification allows to see internal structures of bacteria.
Microbes are distributed differently in different parts of the body, and each body site has different according microbes that can survive there.
Fun fact: Ticks are not considered microbe.
Antonie van Leeuwenhoek is considered the "Father of Microbiology", because he first developed the simple compound microscope with 200x magnification.
He was able to look at microorganisms in many substances, such as dental plaque.
In Louis Pasteur's swan necked flask experiment, media in upright, intact flask didn't get contaminated with bacteria, why?!
The Bacteria entering through the open end of the flask couldn't migrate up the swan neck of the flask to encounter media.