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Brief Record of Microbiology

  3. Cells are of two types:
  4. 1- Prokaryotic skin cells (pro = before, karyon = nut or kernel). Example: Bacteria
  1. 2- Eukaryotic cells (European union = true, karyon = nut or kernel). Good examples: Algae, fungi, protozoa, higher crops and pets or animals.
  2. Biologists have divided living organisms into five kingdoms:
  3. Fungi (Mycology)
  4. Protozoa (Protozoology or Parasitology)
  5. Algae (Phycology)
  6. Prokaryotes (Bacteriology)
  7. Other Organisms WORTH FOCUSING ON To Microbiologists
  8. The Golden Get older of Microbiology
  9. 1- Is spontaneous generation of microbial life possible?
  10. 2- What causes fermentation?
  11. 3- What can cause diseases?
  12. 4- How do we prevent infection and disease?
  13. 1- Is Spontaneous Era Of Microbial Life Possible?
  14. Redi's Test (1626-1697).
  15. Needham's Test (1713-1781).
  16. Spallanzani's Test (1729-1799).
  17. Criticisms of Spallanzani's work were:
  18. Pasteur's Test (1822-1895).
  19. The Swan Neck Experiment
  20. 2- WHAT CAN CAUSE Fermentation?
  21. 3- WHAT CAN CAUSE Diseases?
  22. Gram's stain
  23. 4- HOW DO We Prevent Contamination And Disease?
  24. 1- Semmelweis and Hand washing
  25. 2- Lister's Antiseptic Technique
  26. 3- Nightingale and Nursing
  27. 4- Snow and Epidemiology
  28. 5- Jenner's Vaccine
  29. 6- Ehrlich's powerful bullets and Chemotherapy
  30. The MODERN DAY of Microbiology
  31. 1- How Do Genes work?
  32. Molecular biology.
  34. A- Molecular Biology
  35. B- Recombinant DNA technology
  36. C- Gene therapy
  37. 2- What Jobs Do Microorganisms Play in the Environment?
  39. 4- The Scope And Relevance of Microbiology
  40. 6- EXACTLY WHAT WILL The Future Keep?

Keywords: background of microbiology, microbiology introduction

1- HOW DO Microbes Be Labeled?

Fungi, Protozoa, Algae, Prokaryotes and other microorganisms of importance to microbiologists

B- The Golden Years of Microbiology

1- Is Spontaneous Technology Of Microbial Life Possible?

Redi's Test, Needham's Experiment, Spallanzani's Experiment, Pasteur's Experiment.



Microbiology is the study of organisms and providers too small to be seen obviously by the naked eyesight. It's the analysis of microorganisms, or bacteria or microbes. However, some of these microorganisms are large and noticeable by our naked eyesight such as mushrooms, brown algae, and lichens.

Viruses, bacteria, algae, fungi, and protozoa belong to microorganisms.

Life would not exist without microorganisms. Crops rely upon microorganisms to help them obtain their nitrogen they need from air. Animals such as cows and sheep need microorganisms in order to process the cellulose in their diets.

Our ecosystem rely on microorganisms to enrich soil, degrade wastes and aids life. Without microbial recyclers, the globe would be buried under lifeless organisms.

We use beneficial microorganisms to make our food such as cheese, yoghurt, bread, to build up our vaccines, hormones, vitamin supplements and antibiotics. The body is home to vast amounts of microorganisms, a lot of which help keep us healthy.

Microorganisms aren't only an important part of our own lives; they are quite literally a part of us. Microorganisms can be both beneficial and unsafe (infectious disease realtors) to humans, pets or animals and vegetation.

Some dangerous microorganisms also do cause diseases, from the normal cold to AIDS. The hazards of bioterrorism and new or re-merging infectious diseases are real problem.

We will explore all the assignments (both unsafe and beneficial) that microorganism's play in our lives in this attractive course.

  • Importance of bacteria

Bacteria can be grouped into hazardous and useful bacterias, while some bacterias are non harmful-non useful.

  • Harmful bacteria

1- Bacterias cause some major diseases to humans, animals and vegetation. Among these diseases: cholera, typhoid, tetanus, pneumonia, tuberculosis and meningitis.

2- Some pathogenic bacterias produce poisonous chemicals called toxins which have an impact on certain elements of the web host body.

3- In food industry, bacteria cause spoilage of food and food poising.

  • Useful bacteria

1- Bacterias produce antibiotics which for the treating diseases.

2- Bacteria provide enzymes for natural washing powders.

3- Bacteria are used as microbial insecticides protecting crops from bugs.

4- Bacteria are used to leach out metals from some low level ores such as copper and gold.

5- Bacterias contribute greatly to food industry (butter, parmesan cheese, and yogurt).

6- Certain bacteria are used to convert lactose (dairy sweets) into lactic acid.

7- Certain bacterias are being used to convert liquor into vinegar.

8- Bacteria have an important role in the natural cycles of matter. In the soil, bacteria impact fertility, framework and production of corps.

One of the most crucial roles of bacteria is the breakdown of dead microorganisms and organic wastes into its basic inorganic parts. Skin tightening and, water, nitrogen, and sulfur are some of the most important materials went back to the ground and atmosphere. Such bicycling of materials could not arise in the absence of certain bacterias.

9- To be a source of food (one cell health proteins (SCP). Bacterias are a good way to obtain (SCP) with a great deal of food and space. (SCP can be produced using bacteria growing in throw away paper, contaminants or any food waste materials product).

  • The Early Years Of Microorganisms

The early years of microbiology helped bring the first observations of microbial life, and the initial efforts to arrange them into rational classification.

Early investigators suspected the existence of microorganisms and their role in disease development even before microorganisms were discovered.

The first person seen and detailed microorganisms was Antony vehicle Leeunwenhoek (The Father of Bacteriology and Protozoology) (Dutch) in 1674. He was a tailor and a zoom lens grinder. He used to manufacture lenses to look at the quality of the clothes.

He created simple microscope in 1674 and he noticed, drew, and assessed many minute living microorganisms including bacteria and protozoa in fish-pond water. He also detailed the action, morphology and diversity of bacterias and protozoa.

  • How Can Microbes Be Classified?

Shortly after Leeunwenhoek made his discoveries, the Swedish botanist Linnaeus developed a taxonomic system-that is something for naming crops and pets and grouping similar organisms jointly. Linnaeus and other researchers of this period grouped all organisms into either creature kingdom or the seed kingdom. Today biologists use the five kingdoms classification system and the three kingdoms classification system.

The microorganisms that Leeunwenhoek referred to can be grouped into five basic categories: fungi, protozoa, algae, prokaryotes and small pets. The one microbes not identified by Leeunwenhoek are infections which are too small to be seen lacking any electron microscope.

Cells are of two types:

1- Prokaryotic skin cells (pro = before, karyon = nut or kernel). Example: Bacteria

(i) Organisms very easy in shape.

(ii) The cells lack true membrane delimited nucleus.

2- Eukaryotic cells (European union = true, karyon = nut or kernel). Good examples: Algae, fungi, protozoa, higher crops and pets or animals.

(i) Morphologically more technical than prokaryotes and larger in proportions.

(ii) Microorganisms with true nucleus. They have a membrane enclose nucleus. .

Biologists have divided living organisms into five kingdoms:

1- Kingdom Monera or Prokaryote: includes prokaryotic microorganisms (Bacterias and archea) and Cyanobacteria (the blue-green bacteria, previously called blue-green algae).

2- Kingdom Protista: Include either unicellular or colonial eukaryotic microorganisms that lack true tissues (Protozoa, small algae, and lower fungi).

3- Kingdom Fungi: Includes eukaryotic organisms with absorptive nutrition and frequently multinucleate. Fungi includes moulds (filamentous fungi) and yeasts (unicellular fungi).

4- Kingdom Animalia: Multicellular family pets with ingestive nourishment (Vertebrates and invertebrates).

5- Kingdom Plantae: Multicellular plants with walled eukaryotic cells and photosynthetic capacity.

Viruses do not fit in to the classification of living microorganisms (five kingdoms classification system) because they are reliant on other cells for their reproduction (obligate parasites). Nevertheless infections are also researched by microbiologists.

The recent classification divided microorganisms into 3 kingdoms based on the research of the 16S RNA.

1- Bacterias (True bacterias or Eubacteria).

2- Archaea (Archaeobacteria).

3- Eukarya (All eukaryotic microorganisms).

Fungi (Mycology)

Fungi are microorganisms whose cells are eukaryotic with a genuine nucleus ornamented by a nuclear membrane. Fungi differ from animals insurance agencies cell wall space. Fungi are different from plants because they are heterotrophic (obtain their food from other microorganisms which differs from plants (obtain their food by themselves through photosynthesis i. e. autotrophic).

Microscopic fungi include molds (filamentous fungi) and yeasts (unicellular fungi). Molds are multicellular microorganisms that are grow as long filaments called hyphae that intertwine to make up your body of the mold. Molds reproduce by intimate and asexual spores which produce new individuals.

Yeasts are unicellular and they reproduce by budding. Many types of fungi are advantageous plus some are also very harmful to humans leading to many diseases.

Mushroom is an example of macroscopic fungi. Some mushrooms are also poisonous and can cause loss of life.

Protozoa (Protozoology or Parasitology)

Protozoa are solitary celled eukaryotic microorganisms with true nucleus that are similar to pets in their dietary needs and mobile structure. The suffix protozoa in Greek imply (the first pets). Most protozoa can handle locomotion through pseudopodia, cilia or flagella.

Protozoa typically live easily in water, but some live inside animal hosts, where they can cause diseases. Most protozoa reproduce asexually, however some can reproduce sexually.

Algae (Phycology)

Algae are unicellular or multicellular photosynthetic autotrophic organisms. Algae are classified based on their pigmentation, storage space products and their cell wall surfaces.

Large algae commonly called seaweeds and kelps are normal in the oceans. Unicellular algae are common in freshwater ponds, channels and lakes and in the oceans as well. They are the major food source of small aquatic and marine family pets and provide almost all of the world's air as a by-product of photosynthesis.

Prokaryotes (Bacteriology)

Prokaryotic microorganisms are unicellular microbes that lack nuclei. You can find two varieties of prokaryotes: true bacterias (Eu-bacteria) and archaea (Archaeobacteria). Bacterial cell surfaces are composed of an polysaccharide called peptidoglycan, although some bacteria lack cell walls. Bacterias without cell wall space are called mycoplasma. The cell wall surfaces of archaea absence peptidoglycan and instead are comprised of other polymers.

Most bacterias and archaea are much smaller than the eukaryotic microorganisms. True bacterias are found in every environments, however, archaea are only within extreme surroundings (Difficult or severe environments) (e. g. High or low temperatures, high or low pH, high salinity, high pressure).

Other Organisms WORTH FOCUSING ON To Microbiologists

Microbiologists also examine parasitic worms which range in proportions from microscopic varieties to adult tapeworms over 7 meters long.

The only type of microbes that continued to be covered from Leeunwenhoek and other early microbiologists are infections, viroids and prions which are much smaller than the tiniest prokaryotic microorganisms and are not visible by light microscopy. Infections cannot seen until the electron microscope was created in 1932.

All complete infections are acellular (not composed of cells) obligatory parasites made up of small amounts of genetic materials (genome) (RNA or DNA never both) bounded by a necessary protein coat. The imperfect virus (Prions) consists only of necessary protein coat and there is no nucleic acid in support of attacks human being and animals. While the incomplete trojan (Virioid) comprises only of nucleic acid and there is absolutely no protein coat in support of attacks plant life.

Leeunwenhoek fist reported the lifestyle of microorganisms in 1674, but microbiology didn't develop significantly as a field of research for nearly two centuries. There have been lots of reasons for this delay. First, Leeunwenhoek was a suspicious and secretive man. Though he built over than 400 microscopes, he never trained an apprentice, and he never sold or provided away a microscope. When Leeunwenhoek perished, the secret of fabricating superior microscope was lost. It got almost a century for researchers to make microscopes of equivalent quality.

Another reason that microbiology was poor to develop as a knowledge is that researchers in the 1700s considered microbes to be curiosities of nature and in-significant to human affairs. But in the later 1800s, scientists started to adopt a new philosophy, the one which demand experimental evidence alternatively than mere acceptance of traditional knowledge. This fresh philosophical base, accompanied by much better microscopes, new laboratory techniques, and a drive to answer a series of important questions, propelled microbiology to the forefront as a scientific discipline.

The Golden Get older of Microbiology

For about 50 years during what is now called "The Golden Age group of Microbiology", researchers were powered by the seek out answers o the following 4 questions:

1- Is spontaneous generation of microbial life possible?

2- What causes fermentation?

3- What can cause diseases?

4- How do we prevent infection and disease?

Competition among experts, who were striving to be the first ever to answer these questions, drove exploration and breakthrough in microbiology during the late 1800s and early 1900s. These scientist's discoveries and the areas of research they initiated continue steadily to shape the course of microbiological research today.

1- Is Spontaneous Era Of Microbial Life Possible?

In the old times, many individuals thought that living organisms could develop from non-living subject, and they known as this occurrence as spontaneous era (abiogenesis). Aristotle presumed that simple invertebrates could come up by spontaneous generation. He also believed that frogs and shrimps could occur from mud, bugs from the morning dew and maggots from decaying meats. The validity of the theory arrived under task in the 17th hundred years.

Redi's Test (1626-1697).

The spontaneous technology discord was finally challenged by the Redi (1688), who carried out a series of experiments using decayed meat and he studies the power of meat to produce maggots spontaneously. He figured maggots do not arise by spontaneous technology.

In unsealed flask: The maggots protected the meat within few days.

In the covered flasks: The flies were kept away no maggots appeared on the beef.

In the gauze-covered flask: The flies were placed away no maggots came out on the meats, although a few maggots came out at the top of the gauze.

Needham's Test (1713-1781).

He boiled meat broth in a closed flask. Some days and nights later he demonstrated that many of the flasks became cloudy and included microorganisms. He thought that the organic subject in the beef contained a essential force which could give the properties of life from non-living matter. Since he heated up the flasks he thought that the microorganisms is from the non living meat broth.

Spallanzani's Test (1729-1799).

Spallanzani's in 1799 reported results that contradicted Needham's results. Spallanzani boiled some infusions for one hour and covered the vials by melting their slim necks sealed. His infusion remained clear, unless he broke the seal and exposed the infusion to air, after which they truly became cloudy with microorganisms. He concluded three things:

1- Needham acquired either failed to heating his vials sufficiently.

2- Microorganisms exist in the air and can contaminate the experiments.

3- Spontaneous era of microorganisms does not appear. All living things come up from other living things.

Criticisms of Spallanzani's work were:

1- The covered vials did not allow enough air for organisms to survive.

2- The continuous heating for very long time (1 hour) demolished the "Life force".

The debate continuing until the French chemist Louis Pasteur conducted tests that finally fixed the idea of spontaneous generation to relax.

Pasteur's Test (1822-1895).

In 1861, Pasteur (The Father of Microbiology) fixed the spontaneous generation conflict.

The Swan Neck Experiment

Pasteur placed nutrient alternatives in flasks warmed their necks in a fire and drew them out in a variety of curved designs, and he stored the ends of the throat open to air. Then boiled the nutrient solutions for a few momemts and allowed them to cool. No microbial growth was discovered; even the flask articles were subjected to the external air currents.

Pasteur remarked that no growth was discovered because particles and germs have been collected on the wall surfaces of the curved pre-heated necks. When the necks were cracked, microbial growth came out. The results obtained by Pasteur were contrary to the spontaneous era theory.

2- WHAT CAN CAUSE Fermentation?

Pasteur developed the pasteurization a process of heat the grape drink just enough to wipe out most contaminating bacterias without changing the drink backs qualities so it could then be inoculated with fungus to ensure that alcoholic beverages fermentation took place.

Pasteur thus began the field of professional microbiology or biotechnology in which microbes are used to make beneficial products.

Today pasteurization is used routinely on milk to eliminate pathogenic bacterias that cause tuberculosis and it is also used to get rid of pathogenic bacteria and fungi in juices and other drinks.

Because of Pasteur many significant accomplishments in working with microbes, Pasture is definitely the Daddy of Microbiology.

3- WHAT CAN CAUSE Diseases?

Robert Koch (German Doctor) (the fantastic years of microbiology 1880-1920) was the first person to demonstrate the role of bacterias in causing anthrax disease in 1876. Koch's confirmation that Bacillus anthracis caused anthrax.

Koch discovered that bacteria are in charge of causing a disease. This was called the germ theory of disease. The research of etiology (the analysis of causation of diseases) was dominated by Robert Koch.

Koch established conditions for demonstrating the causal romance between a microorganism and a particular disease. These requirements are known as Koch postulates, and it can be summarized as follows:

(i)- The organism should be constantly present in animals or plants suffering from the illness and should not be present in healthy individuals.

(ii)- The organism must be cultivated in real culture from the pet or seed body.

(iii)- Such a culture when inoculated into susceptible animals or plants should start the quality disease symptoms.

(iv)- The organism should be re-isolated from these experimental pets or animals or plants and cultured again in the lab, after which it will still be the same as the initial organism.

Koch also developed press suited to the isolation of genuine bacterial civilizations from human body. He developed nutrient broth and nutrient agar multimedia.

In 1882 Koch has used these methods to isolate the bacterias that cause tuberculosis.

During Koch's studies on bacterial pathogens, it became necessary to isolate suspected bacterial pathogens. At first, he cultured bacterias on sterile floors of lower, boiled potatoes. This is unsatisfactory because bacterias would not always expand well on potatoes because of the acidity of the potato tissues.

He then tried out to solidify regular liquid medium by adding gelatin. Independent bacterial colonies developed following the surface had been streaked with a bacterial test. Once the gelatin medium solidified, individual bacterias produced separate colonies. Despite its advantages, gelatin was not a perfect solidifying agent because it was digested by many bacteria and melted when the temperature rose above 28C.

Fannie Hesse advised a better alternate. She suggested the use of agar as a solidifying agent. Agar comes from red algae. Agar had not been attacked by most bacteria and didn't melt until attaining a heat of 100C unlike gelatin.

Richard Petri developed the Petri dish (Dish) in 1887, a box for making sound culture press. This development permitted the isolation of clean cultures that contained only an individual microorganism.

Koch and his fellow workers are also accountable for many other developments in laboratory microbiology, including the following:

Simple staining techniques for bacterial cells and flagella.

The first photomicrograph of bacterias.

The first photo of bacteria in diseased tissue.

Techniques for estimating the number of bacteria in a solution based on the number of colonies that form after inoculation onto a good surface.

The use of vapor to sterilize development media.

The use of Petri meals to hold solid growth marketing.

Aseptic lab techniques such as transferring bacteria between marketing using platinum line that is sterilized in a fire.

Koch hypothesized that all bacterial colony consisted if the progeny of a single cell.

Koch use lab animals to inject bacteria and analysis disease development.

For these accomplishments, Koch is considered as the daddy of the Microbiological laboratory.

Gram's stain

Although Koch reported a simple staining strategy in 1877, the Danish scientist Gram developed a more important staining method in 1884. His process which involves the use of group of dyes made some microbes blue and other's red. The blue cells are called the Gram positive and the red skin cells are called the Gram negative. We now use Gram Stain to split up bacteria into these two large groupings.

The gram stain is still the most widely used staining technique. It really is one of the first steps carried out in any lab where bacteria are being revealed.

4- HOW DO We Prevent Contamination And Disease?

1- Semmelweis and Hand washing

Semmelweis was your physician began needing medical students to clean hands with chlorinated lime water.

2- Lister's Antiseptic Technique

Joseph Lister (1867), an British physician found indirect evidence that microorganism were brokers of real human disease. He done preventing wound disease. He developed a system of antiseptic surgery made to prevent microorganism from stepping into wounds. Tools were heat sterilized and phenol was applied to operative dressings and sprayed in the medical area. He provided a strong data for the role of microorganisms in disease development because phenol which killed bacteria also averted wound attacks.

3- Nightingale and Nursing

Nightingale was an English nurse and she actually is the founder of modern medical and she released cleanliness and antiseptic techniques into nursing practices.

4- Snow and Epidemiology

John Snow an British physician plays an integral role ion setting up standards once and for all public hygiene to prevent the pass on of infectious diseases.

His analysis was the building blocks for just two branches of microbiology (an infection control) and epidemiology (study of the occurrence, distribution and get spread around of disease in humans).

5- Jenner's Vaccine

On 1796, Edward Jenner used cowpox-infected materials to efficiently vaccinate people against individual small pox.

He names the procedure vaccination after Vaccinia, the virus that triggers cowpox.

Jenner invented vaccination or immunization.

In honor of Jenner's use cowpox, Pasteur used the term vaccine to refer to all weakened defensive strains of pathogens.

6- Ehrlich's powerful bullets and Chemotherapy

Ehrlich found that chemicals could be used to kill microorganisms.

He uncovered chemicals lively against trypanosomes the protozoan that causes sleeping sickness and against Treponema that cause syphilis. His discoveries started out the branch of chemotherapy.

The MODERN DAY of Microbiology

1- How Do Genes work?

Over days gone by 40 yeasts, developments in microbial genetics developed into several new disciplines that are among the faster growing areas of clinical research today; including:

Molecular biology.


A- Molecular Biology

Molecular biology combines aspects of biochemistry, cell biology and genetics to explain cell function at the molecular level.

Molecular biologists are concerned with genome sequencing.

A full understating of the genomes of microorganisms will result in functional ways to limit disease, repair genetic problems and enhance agricultural produce.

B- Recombinant DNA technology

Molecular Biology is applied in recombinant DNA technology, commonly called genetic engineering that was first developed using microbial models. This consists of the creation of individual insulin in genetically made bacteria.

C- Gene therapy

An fascinating new section of study is the utilization of recombinant DNA technology for gene therapy. This is a process that involves placing a lacking gene or restoring a faulty gene in individuals cells. This process uses harmless trojans to insert a desired gene into coordinator skin cells where it is designed into a chromosome and begins to operate normally.

2- What Jobs Do Microorganisms Play in the Environment?

The research of microorganisms in their environment is called environmental Microbiology or microbial ecology.


Advancements in chemotherapy were made in the 1900s with the discovery of numerous substances such as penicillin and sulfa drugs that inhibit bacteria.

4- The Scope And Relevance of Microbiology

Microbiology has both basic aspects and applied aspects. A scientist working in the field of microbiology is named a microbiologist. Many microbiologists are interested in the biology of microorganisms. They could focus on a particular band of microorganisms and are called: Virologist (Virology is the analysis of trojans), Bacteriologist (Bacteriology is the analysis of bacterias), Phycologist (Phycology is the study of algae), Mycologist (Mycology is the study of fungi), and Protozoologist (Protozoology is the study of protozoa).

Other microbiologist work in other domains such as microbial physiology, microbial cytology, microbial ecology, and microbial taxonomy. Other microbiologists have more practical applied areas such as medical microbiology, food and dairy microbiology, and public health microbiology.

Medical Microbiology: Handles human and pet animal diseases.

Agricultural Microbiology: Deals with the application of microorganisms in agriculture.

Public health Microbiology: Deals with the control of the spread of diseases.

Food and dairy products Microbiology: Deals with the use of microorganisms by man to make foods such as parmesan cheese, breads, and other important products.

Industrial Microbiology: Handles the industrial program of microorganisms such as the production of vaccines, antibiotics, vitamins and enzymes.

Microbial Ecology or Environmental microbiology: Handles the relationship between microorganisms and their surroundings.

Microbial physiology and Biochemistry: Deals with the study with physiology of microorganisms and the effects of physical and chemical substance realtors on the success of microorganisms.

6- EXACTLY WHAT WILL The Future Keep?

What will microbiologists discover next?

Among the questions for another 50 years are the following:

1- What's the physiology of life forms that can't be grown in lab and only recognized to us now by their nucleic acid sequences?

2- Does life are present beyond the world, and when so, what are its features?

3- How do we decrease the risk of infectious diseases, especially those that can be used by bioterrorists?

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