Lab 2 Reem Alsharief

Microbes (or microorganism): are organisms that are too small to be seen by the unaided eye they include bacteria, fungi, protozoa, microalgae and viruses. They live in familiar settings such as soil, water, food, animal intestines, rocks, hot springs and deep sea vents. The wide variety of microbial habitats reflects an enormous diversity of biochemical & metabolic traits that have arisen by genetic variation.

Is the totality of genetic material in the DNA of a particular organism. Genomes differ greatly in size & sequence across different organisms. Obtaining the complete genome sequence of a microbe provides crucial information about its biology, but is the only first step toward understanding a microbe’s biological capabilities and modifying them, if needed, for agriculture purposes

The mapping of microbial genomes is a key technology to understanding microorganisms and devising ways to improve their use in agriculture production, food safety & security, Biotechnology, human nutrition, functional foods, plant& animal protection and bio- based chemicals

1-The Light Microscope: a type of microscope which uses visible light and a system of lenses to magnify images of small samples 2-Autoclave: is an instrument used to sterilize equipment & supplies by subjecting them to high pressure saturated steam at 121̊ C for around minutes depending on the size and the load and the content.

3-Incubator: is a device used to grow and maintain microbiological cultures on cell cultures. 4- Hot Air Oven: are electrical devices used in sterilization, it uses dry heat to sterilize articles, operated from ̊ C 5-Water Bath: is a tool used to maintain a very stable temperature. 6- PH meter: an electronic instrument used for measuring the PH of liquid. 7- colony counter: used to count colonies of bacteria or other microorganism growing on agar plate.

8-Delicate Scales: it is used to scale some cultures& chemical objects in high tech. 9-Bunsen burner: it produces a single open flame which is used for heating, sterilization and combustion> 10-Magnetic Stirrer: a device that employs a rotating magnetic field to cause a stir bar immersed in a liquid to spin very quickly. 11- Hot Plate: are generally used to heat glassware or its contents. 12-Vortex Mixer: a simple device used commonly in laboratories to mix small vial and liquids

13- Centrifuge: it puts an object in rotation around a fixed axis applying a force perpendicular to the axis. 14- Spectrophotometer: is the quantitative measurement of the reflection or transmission properties of material as function of wave length. 15-Biosafety cabinet: is an enclosed, ventilated laboratory workspace for safety working with materials contaminated with pathogens requiring a defined biosafety level.

Petri dish Glass Pipettes Microscopically slides Cover slide

Inoculating Loop Inoculating Needle Culture Tubes Cork Borer Holder Forceps filter Paper

Conical flask Beaker Funnel Cylinder Cotton Swab spatula

Glass Rod Pipette Pump Lab thermometer Staining dishes Dropper Petri dish sterilizing box

Sterilization (or sterilisation) is the elimination of all transmissible agents (such as bacteria, prions and viruses) from a surface or piece of equipment. This is different from disinfection, where only organisms that can cause disease are removed by a disinfectant. Sterilization Methods: First: Heat Sterilization: Probably the most widely used method for sterilization. heat methods include using dry heat, moist heat, flaming and incineration

A-flaming : is done to loops and straight-wires, Leaving the loop in a Bunsen burner until it glows red, ensures that any infectious agent gets oxidized completely into small molecules. Heating small metal or glass objects is really the extent to which this method is used. B-Incineration will also burn any organism to ash It obviously is only used to sanitize unwanted medical and other waste before its ash goes to the tip C-Dry heat can be used to sterilize glassware, fixed oils and Thermo table powder, but as the heat takes much longer to be transferred to the organism, both the time, and the temperature required, must be increased. The standard setting for a hot air oven is at least two hours at 160°C. A rapid method heats air to 190°C for 6–12 hours. Dry heat has the advantage that it can be used on powders and other heat-stable items that are adversely affected by steam.

D-Moist Heat: Kills microorganisms by coagulating their proteins. In general, moist heat is much more effective than dry heat. Boiling: Heat to 100 o C. Kills vegetative forms of bacterial pathogens, almost all viruses, and fungi and their spores within 10 minutes or less. Endospores and some viruses are not destroyed this quickly. However brief boiling will kill most pathogens. Examples: Hepatitis virus: Can survive up to 30 minutes of boiling. Endospores: Can survive up to 20 hours or more of boiling However, reliable sterilization with moist heat requires temperatures above that of boiling water so Steam under Pressure by using the Autoclave is the preferred method of sterilization where temperature of steam reaches 121 o C for 15 min-20 min.The steam and pressure allow sufficient heat is transferred into the organism to kill them

It is a physical removal of microorganisms by adsorption on the filter medium. Used for heat sensitive materials. Equipments needed for bacterial filtrations are: Porcelain filters Siliceous earth filters Sintered glass filters Asbestoses filters Membrane filters

Third: Gasous Sterilization : Equipment: special oven for admission of gas and humidity and hermetic Method: humidity of less than 20% RH and the use of Ethylene Oxide Forth: Radiations sterilizations: Equipment: Ultraviolet Lamp-Ionization( Beta Rays, Gamma Rays, X-Rays) Fifth: Sterilization by chemicals: Bactericides (Germicides): substance that kills vegetative bacteria and some spores Bacteriostat : substance which stops growth and multiplication of bacteria but does not necessary kill them. Growth usually resumes when bacteriostat is removed. Antiseptic: Substance used to prevent multiplication of microorganism when applied to living systems. Viricide: an agent that inactivate viruses Fungicides: an agent that kills fungi Some of these chemical substances: Ethyl Alcohol 2. Chloroform 3. Phenol 4. Cresol 5.Mercuric chloride

Culture is the term given to microorganisms that are cultivated in the lab for the purpose of studying them. Medium is the term given to the combination of ingredients that will support the growth and cultivation of microorganisms by providing all the essential nutrients required for the growth (that is, multiplication) in order to cultivate these microorganisms in large numbers to study them

Among the different kinds of microorganisms the two groups that can be grown in cultures are bacteria and fungi. Algae and protozoa require many different nutrients that are difficult to anticipate and prepare in the lab. The microorganisms have different nutritional requirements and thus various kinds of culture media have been developed. Primary ingredients required by all living organisms include: a carbon source, water, minerals, and a nitrogen source.

Since there are different kinds of organisms that can be grown in culture media with varying needs, culture media have also been formulated with different ingredients. Culture media may be classified in physical form as: 1. liquid (called broth) 2. semi-solid 3. solid. Media are solidified by the addition of solidifying agents such as agar (inert compound). Varying the concentration of agar will yield varying degrees of solidification.

Culture media may be classified in chemical characteristic as 1.Synthetic media (Defined): A chemically defined medium is one prepared from purified ingredients and therefore whose exact composition is known. 2.Complex media (Non-synthetic :medium contains at least one component that is neither purified nor completely characterized nor even completely consistent from batch to batch. Culture media can also be classified based on the function they perform in determining various characteristics of organism that are able to grow on/in them e.g. Differential, Selective media.

The ingredients in a medium will affect the chemical nature of the medium. This is important because organisms vary in their requirement for different environments. One such property is: pH (which is a measure of the amount of hydrogen ions in a particular medium). This has to be monitored during the preparation of media since this will influence the kind of organisms that are able to grow in the medium. The pH of the medium will thus determine which organisms are able to grow on the medium. For example, fungi prefer acidic media for their growth while bacteria grow on neutral pH media.

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