Chapter 2 MMSC270

Define the first "I" in the Five "I's" of Microbiology

Inoculation: sample is placed into a container of growth medium via inoculation

Define the second "I" in the Five "I's" of Microbiology

Incubation: an incubator creates the proper growth conditions with respect to temperature and gas requirements, chamber to encourage the multiplication of microbes

Define the third "I" in the Five "I's" of Microbiology

Isolation: once the culture has grown they made need to be re-inoculated

define the 4th "I" in the Five "I's" of Microbiology

view after 24 HOURS and observe and record growth

5th "I" in the Five "I's" of Microbiology

Identification

3 physical states of culture media

solid, liquid, semi-solid

Selective media

contains one or more agents that inhibit the growth of certain microbes

Differential Media

allow multiple types of organisms to grow but to display visible differences in how they grow

colony

a discrete mound of cells on a plate

best way to isolate a colony

streak plate technique

Galileo microscope contribution

developed compound microscope

Hooke's contribution to microscopy

published micrographia, lens for illumination

resolution

the capacity of an optical system to distinguish 2 adjacent objects or points from one another

function of oil immersion

to increase resolution

contrast

the degree of bending that light undergoes as it passes from one medium to another, measured by refractive index

real image

formed by the objective

virtual image

formed when the image is projected up through the microscope body to the plane of the eyepiece

Measurement of E coli

1 um

measurement of HIV

10 nm

measurement of poliovirus

10 nm

measurement human eye can see

1 mm

list 3 elements of good microscopy

magnification, resolution, contrast

bright field microscope

can be used for both live and preserved material, quick and cheap

The type of microscope in which you would see brightly illuminated specimens against a black background is _________

dark-field

fluorescence microscope

Instrument used to visualize a specimen that has been labeled with a fluorescent dye; samples are illuminated with a wavelength of light that excites the dye, causing it to fluoresce.

confocal microscopy

a light microscope that uses fluorescent stains and laser (HIGHLY FOCUSED)

advantage of SEM microscope

shows the three-dimensional structure of the object

What might you do to the specimen for TEM

section into thin slices

TEM allows you to see _____

detailed structure of cells and viruses

what is an example of a simple stain

methylene blue

what is an example of a differential stain

gram stain and acid fast stain

gram-stain

differential stain used for clinical samples and colonies

acid-fast stain

differential stain used for mycobacterium

endospore stain

structural stain used for bacillus

flagella stain

structural stain used to identify forms of motility

ingredients of gram stain

crystal violet, iodine mordant, ethanol or acetone, counterstain (safranin)

gram positive

purple thick

gram negative

pink thin

Example of gram positive cocci in pairs

example of gram negative rods

Fastidious organisms

microorganisms that are difficult to grow in the laboratory because they have very specific or demanding nutritional/environmental requirements.

“picky eaters”

contaminated culture

culture shows two or more microbes of uncertain identity that have been introduced into it.

pure culture

contains only one known microbe

mixed culture

a culture with two or more identified microbes

selective agents used in microbiological media

bile salts

antibiotics

differential media displays visible differences in

formation of gas bubbles

colony size

colony color

media color changes

selective media w/ bile salts can isolate

intestinal pathogens

techniques used to prepare specimens for optical microscopy depend on

Type of microscopy available

Aims of the examiner

Condition of specimen

positive staining

A staining technique where the microorganism itself is stained so you can see its shape, size, and arrangement.

negative staining

A staining technique where the background is stained instead of the microorganism, leaving the cells clear against a dark background.

negative staining can yield results concerning

cell size

cell shape and arrangement

the presence of a capsule

simple stain

requires use of only one dye

differential stain

Requires a primary stain followed by a counterstain to distinguish cell types and structures.

Include the Gram, endospore, and acid-fast stains

Characteristics assessed by simple stains

cell size

cell shape

cell arrangement

what type of microscope achieves the greatest resolution and highest magnification

electron microscope