Microbiology and micro organisms using of physical method in controlling it

1) Heat: heat treatment is a simple, inexpensive and lethal. It is the best method if the material being treated is not damaged by heat. Heat penetrates to kill micro organisms throughout the object.

A) Dry heat : it Sterlizes by denaturing protein in the laboratory, used to Sterlizes liquids and material easily charred. Used in food canning.

B) Moist heat : it Sterlizes by denaturing protein in the laboratory, used to sterilize liquids and materials easily charred. Used in food canning

C) Pasteurization : kills certain microorganisms by denaturing the protein. Eliminates pathogens and slows spoilage of milk and certain dairy products, wine, beer (canned evaporated or condensed milk is sterilized).

2) LOW temperature (cold) : Refrigerating and freezing can be used to control microbial growth and reproduction. It slows down chemical reaction. It preserves perishable Materials, including food and microorganisms.

3) Filtration : microorganisms can be efficiently removed by Filtration with either depth filter or membrane filter. This method physically removes cellular microorganisms. Air also can be sterilized by Filtration in the laboratory used to preserve certain beverages.

4) Radiation : some form of electromagnetic radiation kill living things, including microorganisms. The types of radiation that kill bacteria directly are all of shorter wavelength than visible light they are ultraviolet (UV)  light (Radiation with wavelength of 10 to 400nm) and ionization radiation (with a wavelength extending to about 0.01nm).

UV light sterilizes by damaging DNA in the laboratory used to sterilize surfaces

Two forms of ionizing radiation are x-rays and gamma rays. They sterilize by stripping electrons from atoms. Used to sterilize plastic equipment and surface of fresh fruits and vegetables.

Drying : drying (removal of water)  can be accomplished through evaporation is almost never used in the laboratory because it causes chemical changes, but it is widely used in the food industry. Lyophilization, or conversation from solid to gaseous state). This method stops microbial growth and stops most chemical reactions.

In the laboratory used to preserve cultures, proteins, blood.

CHEMICAL CONTROL ON MICROORGANISMS

physical agent are generally used to sterilize objects. Chemical on the other hand, are more often employed in disinfection and antisepsis. The proper use of chemicals agents is essential to laboratory and hospital safety. Chemical also are employed to prevent microbial growth in food and certain chemical are used to treat infectious diseases.

1) PHENOLS : kills most microorganisms by denaturing the proteins. It is used as a germicide.

2) PHENOLIC: kill most microorganisms by denaturing proteins and disrupt plasma membrane. It is used as disinfectants and antiseptics.

3) ALCOHOLS: are the most widely used disinfectants and antiseptics. They are bacterialdal and fungicadal but not sypoticidal, some liquid-containing viruses are also destroyed. The two most popular alcohol germicide are ethanol and isopropanol. Denatures protein and disrupts plasma membrane disinfects surface including skin and thermometers.

4) HALOGENS : kills microorganisms. Oxidizes vital biochemicals. It is used to disinfects surface including skin and water.

5) Hydrogen Peroxide : kills many microorganisms by oxidizing vital biochemicals. It is a mild skin disinfectant.

6) SURFACTANTS (soap and detergent) wash away microorganisms by physically removing them disinfects surface, including, skin bench tops.

7) HEAVY METALS (such as mercury, silver, arsenic, zinc and copper)  kills microorganisms. Heavy metals combine with protein to inactivate the microorganisms used as skin disinfectants.

8) Quanternary Ammonium Compounds (SALT) are used detergent that have antimicrobial activities are effective disinfectants. They disrupt membrane and are widely used as sterilizing agents.

9) ALDEHYDES: both of commonly used aldehydes formaldehydes and glutaraldehydes are high reactive molecules that combine with nucleic acids and protein and inactivate them. They are sporicidal and can be used as chemical sterilants. They are used to preserve tissues, prepare vaccines and sterilize surgical instruments.

10) ETHYLENE OXIDE : many heat-sensitivs items such as machine components structure and cathers are Sterlized with Ethylene oxide Gass it is both microbicidal and sporicidal and kills by combining with cell protein.

Chemotherapeutic Agent : the chemicals discussed so far are appropriate for use either on inanimate object or external host tissues. Chemotherapeutic agents are chemicals that can be used internally because they have selective toxicity that is they target the microbes and do relative little if any harm to the host. Most Chemotherapeutic agents are affective in controlling the growth of bacteria. There are many synthetic antibiotics for treating diseases caused by fungal, protists and viruses.

HOW MICROORGANISMS ARE STUDIED

the most important tool in studying microorganisms is the microscope. Microscope began in the century with Anthony Van Leeuwenhock and his little hand-held Microscope. He is regarded as the "FATHER OF MICROBIOLOGY". microscope crest a visible, detailed images of object that are different types of microscope but all of them depend on three factors I.E. magnification, contract and resolution to produce a clear image.

MAGNIFICATION : the primary function of a microscope is magnification, that is enlargement of image, this is done by using a convex lens (thicker in the center Than the edge). By refraction, it bends paravel rays of light from an object so that they meet at a single point, the focal point An enlarged image of the objects from behind focal point.

CONTRAST : this refers to a different in light intensity. It allows on to distinguish on part of an image from its surrounding. The image we see in a microscope is created by the light that is transmitted through the specimen (an object viewed under microscope).

RESOLUTION : Good resolution means you can distinguish two points in an image that are very close to one another. If resolution is poor, the two point merge and look like one another.

Microbiologist use many types of micro scopes to do their work they included both compound light Microscope and electron Microscopes.

LIGHT MICROSCOPE
a light microscope use a visible light as a source of illumination. A compound light microscope has two lens system and object lens and ocular lens. Another series of lenses called the condenser directs light through the specimen. The objective lens forms an image of the specimen in the tube of the microscope. The ocular lens magnifies and projects the image to the eye. Compound light microscope typically are provided with several objectives lenses : low power (10X),high power (40X), and oil immersion(100x)