Microbiology lab safety

Disinfection

A process that eliminates many or all microorganisms, with the exception of bacteria spores, from inanimate objects =Removal or destruction of all vegetative pathogens (except endospores) from an inanimate object.

+ Colony Forming units (CFUs)

A unit used in microbiology to estimate the number of viable microorganism cells in a sample. Viable is defined as the ability to grow and multiply under the incubation conditions provided.

Additional adjustment

Additional adjustments to the microscope can be made regarding lighting. These fine adjustments will not be addressed in this simulation. As magnification of the image increases, the light intensity decreases and will have to be adjusted. The condenser lens focuses the light on the slide. The sliding bar on the condenser lens is the aperture. As you move the aperture to decrease the light to the slide, the contrast increases. As you move the aperture to increase the light to the slide, the contrast decreases.

Microaerophiles

Aerobes that require Oxygen levels from 2-10% and have a limited ability to detoxify Hydrogen Peroxide and Superoxide Radicals -Requires some oxygen but damage by too much oxygen

Catalase

An enzyme produced in all cells to decompose hydrogen peroxide, a by-product of cell respiration

spectrophotometer

An instrument that measures the proportions of light of different wavelengths absorbed and transmitted by a pigment solution. -The spectrophotometer can be used in microbiology to measure the turbidity of a culture medium. Tubes with no bacterial growth will show zero turbidity. The more growth present, the higher the reading will be. Taking measurements of turbidity, indicating bacterial growth, at various pH levels will determine the range and optimal pH for the growth of the sampled organism.

Obligate anaerobe

An organism that only carries out fermentation or anaerobic respiration. Such organisms cannot use oxygen and in fact may be poisoned by it. -Requires an oxygen free environment

obligate aerobe

An organism that requires oxygen for cellular respiration and cannot live without it. -Requires an oxygen rich environment

Anaerobic jars or packs

Anaerobic jars are used to create an anaerobic environment by using a chemical envelope that, when activated, catalyzes a reaction to remove free oxygen from the container.

Thermophiles

Archaea that thrive in very hot environments, such as volcanic springs. -Require very warm temperatures

extreme thermophiles

Archaebacteria that live in extermely hot environments, such as hydrothermal vents under the ocean -Grow best in extremely high temperatures

Biosafety levels

BSL-1: no special precautions BSL-2: lab coat, gloves, eye protection BSL-3: biosafety cabinets to prevent airborne transmission BSL-4: sealed, negative pressure Exhaust air is filtered twice

bacterial lawn

Bacteria swabbed all over agar to form a uniform growth =organisms heavily inoculated on an agar plate will form a uniform growth across the surface of the plate

Alkalinophile

Bacteria that inhabit alkaline soils and water and can continue to grow at a pH of 11.5 -Optimum pH above 8.0

agar plate

Bacterial culture medium containing agar poured into a petri dish.

Agar media

Bacterial culture medium that contains agar as a solidifying agent and is used for growing microorganisms. -

facultative anaerobes

Can make enough ATP to survive using using fermentation or respiration. -uses oxygen if present but can use anaerobic pathways if absent

Correct order of steps to view a specimen at 40X magnification

Click power switch to turn on light Adjust light to appropriate brightness Focus at 4X using coarse focus knob Adjust ocular lenses to view one image Focus using fine focus knob Adjust the stage to move the star to the center of microscope view Put 10X objective in place Focus using fine focus knob Put 40X objective in place Adjust using fine focus knob

Heavy (or dominant) growth

Descriptor indicating the organism was present in high numbers or in all inoculum regions, dilutions, or concentrations.

Peroxide

O2 charge -2

Growth of microorganisms

The growth of microorganisms can be controlled in the laboratory by placing them in preferred growing conditions (e.g., an incubator) or by restricting their growth (e.g., placing them in a refrigerated cooler).

Field of view with low power lens

The lower the power objective, the greater the field of view. The field of view is the amount of the slide you are able to see through the eyepiece.

personal safety

What types of hazards should you protect yourself from in the laboratory? Spills Splattering Flame Corrosive chemicals Sharp objects

Antisepsis

destroying harmful microorganisms from living tissue -Removal or destruction of all vegetative pathogens (except endospores) from an inanimate object.

biosafety level 2

exposure to infectious agents that can cause disease in humans but whose potential for transmission is limited

agar slants

generally used to grow stock cultures that can be refrigerated after incubation and maintained for several weeks =Bacterial culture medium containing agar in a test tube that is allowed to solidify at an angle and forms a solid, slanted surface.

biosafety 4

high risk of causing life threatening disease ex ebola

Superoxide ion (O2-)

highly reactive

inoculating loop

instrument used to pick up and transfer bacteria =A sterilizable tool made of wire, used to implant or move microorganisms

Tonicity of a solution

measure of the ability of a solution to cause change in cell shape or tone by promoting osmotic flow of water

pH scale

measurement system used to indicate the concentration of hydrogen ions (H+) in solution; ranges from 0 to 14

aseptic technique

method used to make the environment, the worker, and the patient as germ-free as possible -A set of procedures employed in the handling of microbes without causing contamination from outside sources.

Inoculum

microbes that are introduced into a culture medium to initiate growth -a small amount of microorganism used to start a new culture

Mesophiles

moderate temperature loving microbes -Prefer moderate temperatures

sterile

no living microbes -an environment devoid of any living cells

total magnification

objective lens x ocular lens -Total magnification is the overall enlargement of the image of a specimen. To calculate total magnification, multiply the magnification of the ocular lens (10X) with the magnification of the objective lens.

Halotolerant

organisms that can tolerate some reduction in water activity of environment but generally grow best in the absence of the added solute -Can grow in high-salt environments.

Cystology

study of cells

Pathology

study of disease

Histology

study of tissues

Magnification

the ratio of an object's image size to its real size - is the apparent increase in image size

Hypertonic

when comparing two solutions, the solution with the greater concentration of solutes -Higher solute concentration outside the cell resulting in water moving out of the cell causing it to decrease in volume =higher solute concentration, resulting in water moving out of the cell causing it to decrease in volume.

Hypotonic

when comparing two solutions, the solution with the lesser concentration of solutes -Lower solute concentration outside the cell resulting in water moving into the cell causing it to increase in volume =lower solute concentration, resulting in water moving into the cell causing it to increase in volume.

Halophile

"salt-loving" archaea that live in environments that have very high salt concentrations -Require high-salt environments above 13% concentration. Some halophiles are classified as obligate because they require high salt concentrations.

Superoxide

-NADPH oxidase generates superoxide -Can be produced in phagosomes, which contain ingested bacteria and fungi, or it can be produced outside of the cell. -In a phagosome, superoxide can spontaneously form hydrogen peroxide that will undergo further reactions to generate reactive oxygen species (ROS).

oil immersion

100x -The goal of microscopy is to create a magnified image of objects too small to be seen with the eye alone. Brightfield microscopes use a combination of glass lenses and light to view the specimen. Using an oil immersion objective lens allows for higher magnification. Microscopes are often used to study bacteria, cells, and tissues. =In this simulation, you will learn how to correctly switch from the 40X high powered objective lens to the 100X oil immersion lens. Oil immersion is an essential technique for light microscopy. Used only on the 100x power objective, oil immersion is when a drop of immersion oil is added to the slide, contacting both the sample and objective. Without this oil, some of the peripheral light that passes through the specimen is scattered into air or the slide, decreasing resolution. Before you begin Immersion oil can only be used with the 100X objective lens. The oil must be properly removed before using the 4X, 10X, or 40X objectives lenses. Your instructor may have a different specific protocol for cleaning the microscope objective lens and the slide than presented in this simulation. Knowledge of how to operate a brightfield microscope is assumed in this lab simulation.

four objective lenses

4x- scanning, 10x- low power, 40x- high dry, 100x- oil immersion

liquid broth culture

A liquid nutrient medium used for the propagation of microorganisms.

culture

A microbiology term to describe many colonies growing on a plate, on a slant, or in broth. A culture is referred to as a "pure culture" when there is only one type (species) of organism in it.

colony

A microbiology term used to describe a visible mass of bacteria growing together on an agar plate or slant. Colonies are derived from a single microorganism.

Osmosis

Diffusion of water through a selectively permeable membrane =Movement of water across the cell membrane from a hypotonic solution into hypertonic solution -movement of water across the cell membrane due to unbalanced solute concentrations.

growth can be controlled

Growth can also be controlled by placing microbes in an environment with oxygen or in a special growth chamber that contains very little, or even zero, oxygen.

Biosafety Level 1 (BSL-1)

Handling pathogens that do not cause disease in healthy humans

Isotonic

Having the same solute concentration as another solution. -Equal solute concentrations inside and outside the cell resulting in no net change in cell volume =equal solute concentrations inside and outside the cell, resulting in no net change in cell volume.

Resolution

Is the ability to distinguish fine detail

addition visualizing

Often what you want to visualize is not in the middle of the field of view and you must move the slide around to find what you want to study. To move the slide, you move the stage. As you look at the microscope the stage knob on the top moves the stage forward and back. The stage knob on the bottom moves the stage side to side.

Contrast

Refers to ability to distinguish objects, such as cells, from the background

Lab washing Procedure

Select the watch in order to remove any items on your wrists or fingers ' Select the hot water and then cold water in order to turn on warm water Select stream of water from faucet to wet your hands Select soap to apply soap to hands Select nail stick or nail brush to clean nails Select scrub hands to rub wet, soapy hands for at least 20 seconds Select stream of water from faucet to rinse hands Select paper towel to dry hands with a clean paper towel Select the hot water and then cold water with paper towel to turn off water Select trash to throw paper towel away

Indicator strip

Sterilized instruments must be stored in individually packaged sterilization pouches that include an

pure culture

a culture containing a single kind of microorganism -A bacterial culture containing only one strain of microorganism

wet mount

a glass slide holding a specimen suspended in a drop of liquid (as water) for microscopic examination -Fast preparation. Requires no special equipment other than a transfer pipette, slide, and cover slip. Organisms may be viewed in their living state. Movement of motile microorganisms can be observed.

petri dish

a shallow, circular, transparent dish with a flat lid, used for the culture of microorganisms.

cuvette

a straight-sided, optically clear container for holding liquid samples in a spectrophotometer or other instrument. -A spectrophotometer uses a cuvette, which is a straight-sided, optically clear container for holding liquid samples in a spectrophotometer.

colony

a visible mass of microbial cells arising from one cell or from a group of the same microbes -A visible mass of microorganisms formed by replication of a single microorganism on agar surface, often in a petri dish

Peroxidase

an enzyme that catalyzes the oxidation of a particular substrate by hydrogen peroxide

Acidophile

an organism that grows best at low pH; typically below pH 6 -Optimum pH below 5.5

Neutrophile

an organism that grows best at neutral pH, between pH 5.5 and 8 -Optimum pH near 7

osmophile

an organism that grows best in the presence of high levels of solute, typically a sugar -Can grow in high-sugar environment

biosafety level 3

biosafety cabinets to prevent airborne transmission

aerotolerant anaerobes

can tolerate oxygen and grow in its presence even though they cannot use it -Does not require oxygen but not affected if oxygen is present

Psychrophiles

cold-loving microbes -Grow best at cold temperatures