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CHAPTER ONE-THE SCOPE OF MICROBIOLOGY

                           THE SCOPE OF MICROBIOLOGY

 

Microbiology is the study of microscopic organisms.It derives its'name from the Greek words-mikros (small)bios (life) and logos (study).Microbiology are organisms which are tiny and invisible to the naked eye. Since the microbes are living,it follows that microbiology deals with a group of particuar life forms and it comes under the broad domain of biology which includes the study of all aspects of living beind includind man.

where can we fix in microbes in the hierarchy of living beings? Traditionaly, living being are divided into plants and animals.But members of the microbes can be accommodated in both plants[fungi] and animals[protozoa] and some cannot be accommodated in either plants or animals e.g Euglena as they share the character of both plants and animal. In one of the earlier attempt to resolve this problems, HAECKEL[1866] a German zoologist, suggested that there should be a third kingdow besides Plantae and Animalia to include all the microorganisms[protista]

Hackel's classification revised some questions like how to distinugish a fungus from a bacterium or from an alga. The discovery of Prokaryotic and Eukaryotic nature of cells in 1940s rendered the three kingdow classification unsatisfactory. A recent and comprehensive classification by R.H Whitttaker[1969] has five kingdow of living beings:

  • Kingdow Monera
  • Kingdow Protista
  • Kingdow Fungi
  • Kingdow Animalia
  • Kingdow Plantae

Microbiology includes the three [ Monera,Protista and Fungi]. At present, it is agreed that within the preview of microbiology,five major groups of microorganisms-viruses,bacteria,fungi,algae and protozoa are dealt within.

As it is evident from the above discussion,the scope of microbilogy extends to both Eukaryotic as well as Prokaryotic microbes. While dicussing the scope of microbiology,it should be evident to us that it does not deal with the merely the enumeration of diversity or classification but extends to all aspects of microbial life. Microbiology is concerned with the form,sturcture,reproduction,physiology,metabolism,classification and modt importance their economic imprtance importance.

CHAPTER TWO-THE NAMES OF SCIENTISTS THAT DEVELOP MICROSCOPE AND MICROBIOLOGY.

   THE SCIENTISTS THAT ARE INVOLVED IN THE DEVELOPMENT OF MICROSCOPE AND MICROBIOLOGY

The science of microbiology started with the invention of the microscope.

  • The English scientist ROBERT HOOKE is credited with being the first person to use the microscope for acedemic study that was in the early 1660s. In 1665, HOOKE published a landmark book MICROGRAPHIA, which described the microscope world for the first time. He studied plant section in particular cork and he draw what he saw, which was a tiny matinx of cylinderal sturcture he called CELL. Todaybit is condered to be a foundation stone in all understanding of microbiology.
  • ANTONIC VAN LEEUWENHOEK[1632-1723], In the Netherland were using microscope to look at animal and plant tissue. He examined a drop of rainwater and noticed it contained tiny creatures he called 'ANIMALICULES' or littlr eels. He became the first person to study bacteria.
  • EDWARD JENNER[1749-1823] who in 1796 injected COWHAND JAMES PHIL with cowpox. Jenner got credit because he carried out his work using accepted scientific method and wrote it up afterwards,though the ethnic of deliberately injecting experimental subject with small pox some week later is questionable but fortunately,the boy did not develop smallpox and he became rich and famous as a result. it was from this risky beginning that the science of immunization developed.
  • FERDINAND .J. COHN who in 1875 effictively founde the science of bacteriology[a branch of microbiology which studies bacteria]. His main contribution was the classification of bacteria and he coined the term BACILLUS 
  • LIOUS PASTEUR who probably the greatest biologist of the 9th century. He developed the germ theory of disease which was a significant breakthrough in medicine. That utimately improved the health of everyone on the planet. He was also able to prove that life itseif did not spontaneousy come into being through series of experiment using a sterilized flask. He successfully showed that life can only be generated from existing life thus closing debate. Pasteur also showed that FERMENTATION- is a process used in baking and brewing was caused by micro-organisms. As a result of this work, he went to develop the process of sterilizing milk and this was named after him"PASTEURIZATION. He also credted with the development of vaccines most notably for rabies and anthrax. He identified and eliminated disease in silkworms. He was also interested in the idea of panspermia that was promoted by LORD KELVIN in 1871.
  • FRACASTORO[1478-1553] gave syphilis its name in the 6th century and core close to devising a germ theory of disease, an idea that later attracted a number of workers all the way down to the 9th century.
  • SCHWANN and CAGNIARD-LATOUR show that ALCOHOLIC FERMENTATION and putrefraction were due to living organised beings. If one accept the fact that the decomposition of organic materials was due to living organisms.
  • JACOB HENLE in 1840 further commented on the similiarty and with the new found knowledge on the nature of fermentation, he proceed clear conclusion.
  • ROBERT KOCH provided in 1867 the final evidence providing the germ theory. He establish the etiologic role of bacteria in anthrax and as result proposed a set of rules to be followed in the establishment of etiology.
  • PAUL ENHRLICH[1854-1915] it is possible to cure a person suffering from disease by injecting some antiotoxin serum perpared by earlier immunization of a horse or other large animal. This lead to rational cures for infections diseases and was responsible for ENHRLICH's later conception of chemotherapy.
  • ALEXANDER FLEMING[1881-1955] he also found about penicillin which was another important step in the understanding of microbiology.
  • OSWALD AVERY,COLLINS MACLEOD AND MADYH MACANTY. They demonstrated that the transforming principle in bacteria previously observed by FREDRICK GROFFITS in 1928 was DNA.

CHAPTER THREE-THE ROLES OF MICROBIOLOGY

          THE ROLES OF MICROBIOLOGY

  • NURSING: Use of microbiology in nursing is concerned with diagnosis. it helps to see how the patient's health is progresses during the treatment. it gives the knowledge to nurse on how to handle a patient and his sample infected with communicable disease. nurses can also identify blood group of the patient by simple immue reactions. it also helps  to detect diseases like tuberculosis by simple skin test namely the mantoux test. Diagnostic tests like Elisa electrophoreis and randiommie assay use principle of microbiologyfor identification of disease.
  • PHARMACY:  Pharmacy and pharmaceutical companies uses microbiology extensively. it is used for :
  1. For production of medicines like antibiotics,enzymes,vaccines insulin,vitamins,steroids etc.some of the substances are exclusively obtained by microbial cultures.
  2. For sterilization of manufacturred drugs microbes are destoryed by sterilization.
  3. Also many new drugs are in search by use of microbiology. since many antibiotics enzymes etc were derived from microbes,still the microbes are searched for more new drugs.
  • MEDICAL MICROBIOLOGY: In medical microbiology,is taught for the people to understandtheTypes of microbial diseases ie how diseases are caused by microbes.Their types like bacteria,virus,fungi etc.
  • Dignosis  and treatment even the diagnosis of the disease causing microbes is taught so as to give the right drug and combat infection effectively.
  • The identification of specific microbes is done by help of microbiological.
  • AGRICUILTURE:
  1. Natural pesticides- few microbes like bacteria and virus are expoilted against pest attacking farm crop hence they are called natural pesticides.
  2. Natural manure- few microbes lie algae and bacteria are grown up to enhance the soil ferility by fixing nitrogen and also water retaining capacity of soil. They maintain soil microbiology suitable for plant growth.
  3. Decompose the waste- microbes decompose synthetic pesticide residue and other toxin material in the agriculture soil and thereby protecting tarm from toxin accumulation.

 

CHAPTER FOUR-THE PRINCPLES,TYPES AND APPLICATION OF MICROSCOPE.

    THE PRINCIPLES OF THE MICOSCOPES,TYPES AND APPLICATION.

Aplication of the microscope is and the techniques used in historical study and study of microbiology. The microscope is used to determine the morphology or morphological characteristies of micro-organisms such as bacteria, fungi,protozoa,alga and viruses. Morphology can be obtained by using a simple lens e.g hand lens or a microscope. This is because the human eye cannot discern any detail of the object smaller than 0.1mm although smaller object can be seen when they are placed against a contrusting background. There are several types of microscope available for this purpose and many techinques too have been developed by which specimen containing micro-organisms cabn be prepared for examination under the microscope.

                        THE TYPES OF MICROSCOPE

There are two kinds of microscope-light and electron, while the types of microscope are:

  • THE BRIGHT-FIELD MICROSCOPE- the ordinarymicroscope is called the bright field microscope because it forms a dark image against a brighter background. The most commonly used microscope for general lab observation is the bright field microscope. The brighe field is also called the compound micrscope and it has be in form of a moncular and binocular. More advanced microscope haveeyepieces for both eyes and thus are called binocular microscope whereas those with a single eye piece is called moncular microscope. The bright field microscope consist of a study metal body or stand which is composed of a base and an arm to which the remaining part are attached. There is a light source which is neither a mirror or an electric illuminator located in the base. Two focusing knobs,the tine and coarse adjustment knobs are attached on the the arms and can be moved either the stage or the noise piece to focus the image of the object being viewed. The microscope has a condenser, a lens that focuses light directly on the specimen. This makes the entire field of view illuminated.The mechanical stage is positioned about halfway up the arm and held the micrscope slides containing the specimen to be viwed either simple slides chips or mechanical stage chips. A mechanical stage allows the operator to move a slides around smothly during viewing by the use of stage control knobs. The upper arm holds the body assembly to which a nose-piece and one or two eye-piece or oculars are attached. The nose-piece holds the three-five objectives with lenses of different magnifying power which can be rotated to position any object or specimen beneath the body assembly.
  • DARK-FIELD MICROSCOPE--This is another type of light compound microscope equipped with special condenser which directs the light path away from the source of illumination. This effect produced by dark -field techniques is a black background aganist which objects are brighly illuminated. The light directed through the condenser does not enter the objective and the entire field of view is dark. Since the medium contains objects that differ from the its refractive index, there is a scattering of light by reflection and refraction. The scattered light will enter the objects and it will appear bright in the dark microscopic field. Dark-field micrscope is valuable for examination of unstained micro-organisms suspended in field that is wet and hanging drop preparations. An example of the observation of the SPIROCHETES OF SYPHILIS called TREPONEMA PALLADIUM.
  • ULTRA-VIOLET [UV] MICROSCOPE-- A slight increase in the resolving power of the light microscope can be achieved by giving light of a wavelength shorter than the visible light namely ultra-violet radiation, since the human eye cannot see ultra-violet rays, a photographic plate must be used to record the image and the plate is developed later. Furthermore the entire lens system must be constructed of the quart, since glass is opaque to the shorter wavelength in the ultra-violent radition magnification two or three times that of the bright field microscope can be obtained.
  • THE FLUORESCENCE MICROSCOPE---- One of the modification of the ultra-violent microscope which is considerable use in biology and microbiology. Many chemicals substances which absorbs ultra-violent rays are able to re-emit part of the absorbed energy as light of longer [visible] wavelength. The phenomenon is known as fluorscence. It follows that if a fluorscence object is illuminated with ultra-violent ray, it can be preceived by the human eye as a result of its fluorscence. This is the principle which underlies fluorscence microscopy. In practice, the object is illuminated by an ultra-violent beam that passed through a quartz condenser and the fluorescence light is then picked up and transmitted to the human eye throug a filter whivh screens out other wavelength.
  • INTERFERENCE MICROSCOPE----It is used for quantitative studies of marcromolecules of the cell components for example: it is used for determination of the lipids, nucleic acids and protein content in cells. Interferometry is a traditional technique in which a pattern of bright and dark lines fringes result from a optical path difference a reference and a simple beam. The incoming light is split inside an interferometer, one beam goes to an inter reference and the other to the sample. After reflection, the beam recombines inside the interferometer undergoing constructive and destructive interference and producing the light and dark fringes pattern. A precision translation stay and CCD camera together genera a 3D interferogram of the object that is stored in the computer memory. This 3D interferogram of the object is then transformed by the frequency. Analysis into quantitative 3D image providing surface structure analysis.
  • PHASE-CONTRAST MICRSCOPE----This is used to study the behaviour of living cells, observe the nuclear and cytoplasmic changes taking place during the mitosis and the effects of the different chemical inside the living cell. By using the phase-contrast microscope, an image of strong constrast of the object is obtained. It is a contrast-enhancing optical technigue that can be utilized to produce high contrast images of transparent specimens such as the living cell [ in culture] microorganisms,thin tissues, silicied, fibre glass fragments and sub-celluar particles including nuclei and other organelles. In effect, phase-contrast techniques employs an optical mechanism to translate minute variations in phase into corresponding change in amplitude which can be visualized as difference in many contrast. One of the advantages of phase-contrast is that living cells can be examined in their natural state without previously being killed, fixed and steamed. As a result, the dynamic of ongoing biological process can be observed and recorded in high contrast with sharp clarity of minute specimen detail.
  • COMPOUND MICRSCOPE----It consist of two set of convex lenses. A len of short aperture and short focal length facing the object called objective. Another set of lens of relatively moderate focal length and lens aperture facing the eye called the eye piece. The objective and the eye piece are placed coaxially at the two and of a tube. The object is placed between centre of curvature and focus of the objective. It forms real, inverted and magnified image on the other side of the objective. The image acts as a simple eye piece microscope to produce virtual, erect and magnified image.  Magnifying power [m] of a compound microscope will be : m=L/fo(l+D/fe). fo and fe =focal length of the objective and eye, L =length of the micrscope tube, D = least distance of the distnict vision
  • ELECTRON MICRSCOPE----The organelles of the cell became known after the electron microscope was invented. The electron microscope developed in 1932 by H.Knoll and Ruska in Germany. it consist of a source of supply, a beam of electron and uniform velocity, a condenser lens for concentrating the electron on the specimen, a specimen stage for displacing a specimen which transmits the electron beam, an objective lens, a projector lens and a fluoresent screen on which final image is observed. The fluoresent screen is replaced by photographic film. This microscope utilizes a stream of high speed electron which are deflected by a electromagnetic field the same way as a beam of light is reflected when it crosses a glass lens. There are two types of electron microscope. Namely:
  1. TRANSMISSUION ELECTRON MICROSCOPE (TEM)-----It is used to observe the fine structure of cells. Ultra thin section of the object are prepared and they are heavy metals (gold or palladum) to make contain part dense and insert in the vaccum chamber of the microscope. A 100,000 volts electron beam is focused on the section and manipulation prepared from       the image maybe enlarged with enough resolution to achieve total magnification of over 2 million times.
  2. SCANNING ELECTRON MICROSCOPE-----It is used to study the surfaces of the cell and organisms. its image is formed by electron reflected back from the object. the image formed by this microscope has a remarkable three dimensional apperance typically magnification of scanning is around 20,000 times. 

 

 

CHAPTER FIVE-THE VARIOUS MICROBIAL STAINING TECHINQUE.

  THE VARIOUS MICROBIAL STANING TECHNIGUE

STANING: It means coloring of micro-organisms with the dye that emphasizes and elucidate different important structures of micro-organisms including bacteria, virus,protozoa and etc.

                                      IMPORTANCES OF STAINING 

In Microbiology, the concept of staning is very important because it highlights the structure of micro-organisms allowing them to be seen under the microscope ( simple and electron microscope).

  • It is used to differentiate different micro-organisms
  • used fot the identification of micro-organisms like bacteria which  may either be gram postive or gram negative. 

THE VARIOUS TYPES OF STAINING

  • ACID FAST STAIN (Zichl-Neelsen technique)-----I t distinguish acid fast bacteria such as mycotbacterium spp from non-acid fast bacteria; wich do not stain well by gram staning. it is used to stain mycobacterium species (mycobacterium, m.tuberculosis, m.ulcerer, m.leprae). 
  • ACRIDINE ORANGE STAIN----- this staining method is used to confirm the presence of bacteria in blood culture when gram stain result are different to interpret or when presence of bacteria is highly suspected but none are detcted using light microscopy. Acridine orange binds to nuclric acid and stains them. It is also used for the detection of mycoplasms [ cell wall deficient bacteria]
  • AURAMINE-RHODAMINE TECHNIQUE-------This fluorochrome staining method is used to enhance the detection of mycobacteria directly in patient specimens and initial characterization of cell grown in culture.
  • GRAM  STANING---------Gram staining is very important differential staining techiques used in the initial characterization and classification of bacteria in microbiology. it helps to identify bacterial pathogens in specimens and culture by their gram reaction. [[ Gram postive and Gram negative] and morphology [ cocci/ Rod]
  • NEGATIVE STAINING........ Negative stains are used when a specimen or a part of it, such as the capsule resists taking up the stain. India ink preparation is recommended for use in the identification of cryptoccus neoformans.
  • IRON-HEAMATOXYLIN STAINS.......... It is used to stain tissue components such as myclin, elastic and collageric fibres muscle striations etc

 

CHAPTER SIX-THE CHARACTERISTICS OF MICRO-ORGANISMS

THE CHARACTERISTICS OF MICRO-ORGANISMS

BACTERIA:

BACTERIOLOGY, the study of bacteria forms a major part of microbiology. The population of bacteria excceds all other organisms. Bacteria are important because

  • the diseases they cause
  • domestic uses
  • industrial applications
  • agricultural processes

CHARACTERISTICS OF BACTERIA.

     Bacteria are prokaryoticunicelluar organisms. they lack organized nucleus but possess a rigid cell wall comparable to that found in plants.the average size of a bacteriaum is around 2um.It maybe spherical, rod-like, spirally coiled or filament like. based on the response to Gram's stain, the bacteria are grouped as Gram +ve or Gram -ve. Bacteria require oxygene [ AEROBIC BACTERIA] examples are PSEUDOMONAS SP and MYCObacterium sp. some bacteria that do not need oxygene because they are toxin to them [ANAEROBIC BACTERIA] examples are PEPTOCOCCUS SP. (1)Some bacteria grow in anaerobic and aerobic conditions, they are called FACULTATIVE BACTERIA example SHIGELLA SP,SALMONELLA sp AUTOTROPHIC BACTERIA. These bacteria are capable of synthesizing their own food from inorganic substances. they utilize different hydrogen compounds include hydrogen ammonia, hydrogen sulfide and methane e.g [hydrogen-nomonas sp, nitrosomona sp methanomonas sp

(2) HETEROTROPHIC BACTERIA : they cannot synthesize their own food and are therefore dependent on the outside source of food. there are two types - sporophytes and parasite. Sporophytes obtains their food from sources of plant or animal origin. these include organic remains like corpses, animal excereta, meat, fruit. sporophytes secrete digestives enzymes that breaks the complex organic molecules into simple and easily absorbable forms.

Impressum

Tag der Veröffentlichung: 19.10.2016

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this book is dedicated to my parents,siblings,friend,relations and my country.And to all scientists in the world trying to make the world a better to live.this book is also dedicated to Robert Hooke,Antonic Van Leeuwenhoek,Edward Jenner,Lious Pasteur

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