micro practical #1

biosafety level 1

Organisms do not typically cause disease in healthy individuals and present a minimal threat to the environment and lab personnel

student conduct dos and donts

wear closed toed shoes, wear eye protection, turn off bunsen burner, tie back long hair, if feeling ill go home

free living

do not require a specific host to survive

infectious dose

the amount of a pathogen needed to establish an infection in a host

host

organism that serves as a habitat for another organism

biosafety level 2

Organisms are commonly encountered in the community and present a moderate environmental and/or health hazard

biosafety level 2 examples

Salmonella, Staphylococcus aureus, Clostridioides difficile (formerly Clotsridium difficile), and Borrelia burgdorferi.

biosafety level 3

Organisms are of local or exotic origin and are associated with respiratory transmission and serious or lethal diseases where treatment and/or vaccines may or may not be available.

biosafety level 3 examples

Bacillus anthracis, Mycobacterium tuberculosis, and West Nile virus.

biosafety level 1 examples

Bacillus subtilis, Escherichia coli (most strains), Rhodospirillum rubrum, and Lactobacillus acidophilus

biosafety level 4

Organisms have a great potential for lethal infection. Inhalation of infectious aerosols, exposure to infectious droplets, and autoinoculation are of primary concern

biosafety level 4 examples

agents causing hemorrhagic diseases, such as Ebola, Marburg, and Lassa fever viruses.

attenuated

weakened

virulent

able to exert its full disease causing potential

complex/enriched media

contain ingredients such as milk proteins, blood, or yeast extracts, less precisely defined organic nutrients. Most pathogens are fastidious (require complex nutrient sources) and will only grow on this (ex: nutrient broth)

good lab practices when preforming aseptic transfer

pay attention to environment, thoroughly label all media, keep test tubes in test-tube rack, take your time, never hold a tube by its cap, use dominant hand to hold inoculating tools

advantages of anaerobic jar over thioglycollate broth

we’d need to grow our bacterium on specialized biochemical test media while simultaneously maintaining the culture under the bacterium’s optimal atmospheric growth conditions. An aerobic jar facilitates this.

Anaerobic jars are also an ideal way to store and transport anaerobic cultures without having to first transfer the cultures to thioglycollate media

resazurin

be able to label parts of the microscope!!

condenser

iris diaphragm

cell shapes

cell arrangements

chemistry of basic stains

negative stains advantage over simple stain

negative stain doesn’t include a fixation step, it can reveal a species truest size, shape and cellular arrangement

A. foeralis aerotolerance category

facultative anaerobic

C. sporogenes aerotolerance category

obligate anaerobic

S. epidermidis aerotolerance category

obligate anaerobic