Brief history of microbiology

Keywords: record of microbiology, microbiology introduction

1- How Can Microbes Be Classified?

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

B- The Golden Age group of Microbiology

1- Is Spontaneous Era Of Microbial Life Possible?

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


Microbiology is the review of organisms and brokers too small to be seen obviously by the naked attention. It is the analysis of microorganisms, or germs or microbes. However, many of these microorganisms are large and noticeable by our naked eyesight such as mushrooms, brownish algae, and lichens.

Viruses, bacterias, algae, fungi, and protozoa participate in microorganisms.

Life would not exist without microorganisms. Vegetation depend on microorganisms to help them get hold of their nitrogen they need from air. Animals such as cows and sheep demand microorganisms to be able to digest the cellulose within their diets.

Our ecosystem depend on microorganisms to enrich soil, degrade wastes and supports existence. Without microbial recyclers, the community will be buried under dead organisms.

We use effective microorganisms to create our food such as for example cheese, yoghurt, bread, to develop our vaccines, hormones, vitamin supplements and antibiotics. The body is home to vast amounts of microorganisms, many of that assist keep us healthy.

Microorganisms are not only an essential component of our lives; they are quite literally a part of us. Microorganisms can be both beneficial and dangerous (infectious disease brokers) to individuals, animals and plants.

Some harmful microorganisms likewise do cause ailments, from the common cold to AIDS. The threats of bioterrorism and innovative or re-merging infectious ailments are real problem.

We will explore all the roles (both damaging and effective) that microorganism's play inside our lives in this amazing course.

  • Importance of bacteria

Bacteria could be categorized into hazardous and useful bacteria, although some bacterias are non harmful-non beneficial.

  • Harmful bacteria

1- Bacterias cause some major illnesses to individuals, animals and plant life. Among these diseases: cholera, typhoid, tetanus, pneumonia, tuberculosis and meningitis.

2- Some pathogenic bacteria produce poisonous chemical substances called poisons which affect certain elements of the host body.

3- In food sector, bacterias cause spoilage of foodstuff and food poising.

  • Useful bacteria

1- Bacteria make antibiotics which for the treating diseases.

2- Bacteria offer enzymes for biological washing powders.

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

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

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

6- Certain bacteria are being used to convert lactose (milk sugar) into lactic acid.

7- Certain bacteria are used to convert alcoholic beverages into vinegar.

8- Bacteria have an essential role in the pure cycles of matter. In the soil, bacteria affect fertility, framework and productivity of corps.

One of the most important roles of bacteria may be the break down of dead organisms and organic wastes into its basic inorganic parts. Carbon dioxide, normal water, nitrogen, and sulfur will be some of the main materials came back to the soil and ambiance. Such cycling of products cannot occur in the absence of certain bacteria.

9- As a way to obtain food (single cell necessary protein (SCP). Bacteria are a good way to obtain (SCP) with a lot of foodstuff and space. (SCP can be produced using bacterias growing in waste products paper, pollutants or any meals waste product).

  • The Early Years Of Microorganisms

The early on years of microbiology brought the 1st observations of microbial lifestyle, and the original efforts to organize them into logical classification.

Early investigators suspected the existence of microorganisms and their position in disease development also before microorganisms had been detected.

The first person observed and defined microorganisms was Antony van Leeunwenhoek (THE DADDY of Bacteriology and Protozoology) (Dutch) in 1674. He was a tailor and a lens grinder. He used to produce lenses to examine the caliber of the clothes.

He invented simple microscope in 1674 and he noticed, drew, and measured large numbers of minute living organisms including bacterias and protozoa in pond water. He likewise described the motion, morphology and diversity of bacteria and protozoa.

  • How Can Microbes Become Classified?

Shortly after Leeunwenhoek manufactured his discoveries, the Swedish botanist Linnaeus produced a taxonomic system-that is normally something for naming crops and animals and grouping equivalent organisms alongside one another. Linnaeus and other researchers of this period grouped all organisms into either pet kingdom or the plant kingdom. Today biologists use the five kingdoms classification program and the three kingdoms classification system.

The microorganisms that Leeunwenhoek defined can be grouped into five basic groups: fungi, protozoa, algae, prokaryotes and small pets or animals. The only microbes certainly not described by Leeunwenhoek are infections which are too small to be seen lacking any electron microscope.

Cells will be of two types:

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

(i) Organisms very easy in shape.

(ii) The cells lack authentic membrane delimited nucleus.

2- Eukaryotic cells (Eu = authentic, karyon = nut or kernel). Illustrations: Algae, fungi, protozoa, bigger plants and animals.

(i) Morphologically more complex than prokaryotes and larger in size.

(ii) Organisms with true nucleus. They possess a membrane enclose nucleus. .

Biologists have divided living organisms into five kingdoms:

1- Kingdom Monera or Prokaryote: incorporates prokaryotic organisms (Bacteria and archea) and Cyanobacteria (the blue-green bacterias, formerly called blue-green algae).

2- Kingdom Protista: Consist of either unicellular or colonial eukaryotic organisms that lack true tissues (Protozoa, tiny algae, and lower fungi).

3- Kingdom Fungi: Incorporates eukaryotic organisms with absorptive diet and frequently multinucleate. Fungi comes with moulds (filamentous fungi) and yeasts (unicellular fungi).

4- Kingdom Animalia: Multicellular animals with ingestive diet (Vertebrates and invertebrates).

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

Viruses do not fit into the classification of living organisms (five kingdoms classification system) because they are reliant on other cells for their reproduction (obligate parasites). Even so viruses are as well studied by microbiologists.

The new classification divided organisms into 3 kingdoms based on the research of the 16S RNA.

1- Bacteria (True bacteria or Eubacteria).

2- Archaea (Archaeobacteria).

3- Eukarya (All eukaryotic organisms).

Fungi (Mycology)

Fungi happen to be organisms whose cells happen to be eukaryotic with a true nucleus encircled by a nuclear membrane. Fungi differ from animals by having cell wall space. Fungi will vary from plants because they're heterotrophic (obtain their food from different organisms which differs from plants (obtain their food by themselves through photosynthesis i just.e. autotrophic).

Microscopic fungi contain molds (filamentous fungi) and yeasts (unicellular fungi). Molds happen to be multicellular organisms that will be grow as long filaments known as hyphae that intertwine to create up your body of the mold. Molds reproduce by sexual and asexual spores which produce new individuals.

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

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

Protozoa (Protozoology or Parasitology)

Protozoa are solitary celled eukaryotic microorganisms with accurate nucleus that act like animals within their nutritional desires and cellular structure. The suffix protozoa in Greek indicate (the primary animals). Most protozoa can handle locomotion through pseudopodia, cilia or flagella.

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

Algae (Phycology)

Algae are unicellular or multicellular photosynthetic autotrophic organisms. Algae happen to be categorized on the basis of their pigmentation, storage products and their cell wall space.

Large algae commonly named seaweeds and kelps are common in the oceans. Unicellular algae are common in freshwater ponds, streams and lakes and in the oceans as well. They are the major food source of tiny aquatic and marine pets and provide the majority of the world's oxygen as a by-item of photosynthesis.

Prokaryotes (Bacteriology)

Prokaryotic microorganisms are unicellular microbes that lack nuclei. There are two sorts of prokaryotes: true bacteria (Eu-bacterias) and archaea (Archaeobacteria). Bacterial cell walls are composed of a polysaccharide named peptidoglycan, even though some bacteria lack cell surfaces. Bacteria without cell wall space are referred to as mycoplasma. The cell walls of archaea absence peptidoglycan and instead are comprised of other polymers.

Most bacteria and archaea are substantially smaller than the eukaryotic microorganisms. True bacteria are found in every environments, however, archaea are only found in extreme environments (Difficult or harsh environments) (e.g. Superior or low temperature, high or low pH, substantial salinity, ruthless).

Other Organisms WORTH FOCUSING ON To Microbiologists

Microbiologists also examine parasitic worms which array in size from microscopic forms to mature tapeworms over 7 meters in length.

The only kind of microbes that remained concealed from Leeunwenhoek and different early microbiologists are viruses, viroids and prions which will be much smaller compared to the smallest prokaryotic microorganisms and so are not noticeable by light microscopy. Infections could not seen before electron microscope was created in 1932.

All complete infections are acellular (not composed of cells) obligatory parasites made up of smaller amounts of genetic materials (genome) (RNA or DNA by no means both) surrounded by a protein coat. The incomplete virus (Prions) consists only of protein coat and there is absolutely no nucleic acid and sole attacks human and family pets. As the incomplete virus (Virioid) consists just of nucleic acid and there is no protein coat and just attacks plants.

Leeunwenhoek fist reported the existence of microorganisms in 1674, but microbiology did not develop significantly as a field of study for almost two centuries. There were a number of known reasons for this delay. Earliest, Leeunwenhoek was a suspicious and secretive person. Though he built over than 400 microscopes, he never trained an apprentice, and he under no circumstances sold or gave apart a microscope. When Leeunwenhoek died, the secret of fabricating superior microscope was dropped. It took almost a century for scientists to create microscopes of equivalent top quality.

Another motive that microbiology was slow to develop as a technology is that researchers in the 1700s regarded microbes to get curiosities of aspect and in-significant to individual affairs. However in the late 1800s, researchers began to adopt a new philosophy, one that demand experimental proof rather than mere acceptance of classic knowledge. This refreshing philosophical base, accompanied by improved upon microscopes, new laboratory approaches, and a drive to answer a number of important queries, propelled microbiology to the forefront as a scientific discipline.

The Golden Get older of Microbiology

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

1- Is spontaneous technology of microbial life possible?

2- What can cause fermentation?

3- What causes diseases?

4- How can we prevent contamination and disease?

Competition among researchers, who had been striving to be the first ever to answer these problems, drove exploration and discovery in microbiology during the late 1800s and early on 1900s. These scientist's discoveries and the fields of study they initiated continue steadily to shape the span of microbiological research today.

1- Is Spontaneous Era Of Microbial Existence Possible?

In the ancient occasions, many peoples thought that living organisms could develop from non-living matter, and they called this phenomenon as spontaneous generation (abiogenesis). Aristotle believed that easy invertebrates could come up by spontaneous technology. He also believed that frogs and shrimps could occur from mud, bugs from the morning dew and maggots from decaying meats. The validity of this theory came under task in the 17th century.

Redi's Experiment (1626-1697).

The spontaneous era conflict was finally challenged by the Redi (1688), who completed a series of experiments using decayed meat and he studies the ability of meat to produce maggots spontaneously. He concluded that maggots do not arise by spontaneous generation.

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

In the sealed flasks: The flies were held away and no maggots came out on the meats.

In the gauze-covered flask: The flies were kept aside and no maggots came out on the meat, although a few maggots came out on the top of the gauze.

Needham's Experiment (1713-1781).

He boiled beef broth in a sealed flask. Some days afterwards he demonstrated that many of these flasks became cloudy and contained microorganisms. He assumed that the organic and natural matter in the meats contained a essential force that could supply the properties of lifestyle from non-living matter. Since he heated the flasks he assumed that the microorganisms is usually coming from the non living beef broth.

Spallanzani's Experiment (1729-1799).

Spallanzani's in 1799 reported effects that contradicted Needham's findings. Spallanzani boiled some infusions for one hour and sealed the vials by melting their slender necks shut. His infusion remained obvious, unless he broke the seal and uncovered the infusion to air, after which they became cloudy with microorganisms. He concluded three things:

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

2- Microorganisms can be found in the air and may contaminate the experiments.

3- Spontaneous technology of microorganisms does not occur. All living stuff arise from different living things.

Criticisms of Spallanzani's work were:

1- The sealed vials did not allow enough air flow for organisms to make it through.

2- The prolonged heating for long time (one hour) destroyed the "Life force".

The debate continued until the French chemist Louis Pasteur executed experiments that finally solved the idea of spontaneous era to rest.

Pasteur's Experiment (1822-1895).

In 1861, Pasteur (THE DADDY of Microbiology) solved the spontaneous technology conflict.

The Swan Neck Experiment

Pasteur placed nutrient alternatives in flasks heated their necks in a flame and drew them out in many different curved designs, and he placed the ends of the throat open to the air. Then boiled the nutrient alternatives for a few moments and allowed them to cool. No microbial expansion was observed; actually the flask contents had been exposed to the external surroundings currents.

Pasteur remarked that no development was observed because dust particles and germs have been collected on the walls of the curved pre-heated necks. If the necks had been broken, microbial development appeared. The outcomes obtained by Pasteur were against the spontaneous technology theory.

2- WHAT CAN CAUSE Fermentation?

Pasteur produced the pasteurization a process of heating system the grape juice sufficient to kill most contaminating bacteria without changing the juice backs attributes so it could afterward come to be inoculated with yeast to ensure that alcohol fermentation occurred.

Pasteur thus commenced the field of commercial microbiology or biotechnology where microbes are being used to manufacture beneficial items.

Today pasteurization is employed routinely on milk to eradicate pathogenic bacteria that cause tuberculosis and can be used to eliminate pathogenic bacteria and fungi in juices and different beverages.

Because of Pasteur many significant accomplishments in dealing with microbes, Pasture is considered the Father of Microbiology.

3- What Causes Diseases?

Robert Koch (German Doctor) (the golden years of microbiology 1880-1920) was the earliest person to show the position of bacteria in causing anthrax disease in 1876. Koch's evidence that Bacillus anthracis triggered anthrax.

Koch discovered that bacteria are responsible for causing a disease. This was called the germ theory of disease. The science of etiology (the analysis of causation of disorders) was dominated by Robert Koch.

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

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

(ii)- The organism should be cultivated in pure customs away from the animal or plant body.

(iii)- Such a customs when inoculated into susceptible family pets or vegetation should initiate the characteristic disease symptoms.

(iv)- The organism should be re-isolated from these experimental family pets or plants and cultured once again in the laboratory, and it should still be the same as the original organism.

Koch also developed media well suited for the isolation of natural bacterial cultures from human body. He produced nutrient broth and nutrient agar press.

In 1882 Koch features used these methods to isolate the bacteria that cause tuberculosis.

During Koch's studies on bacterial pathogens, it started to be necessary to isolate suspected bacterial pathogens. At first, he cultured bacteria on sterile areas of slice, boiled potatoes. This was unsatisfactory because bacteria wouldn't normally always grow very well on potatoes due to the acidity of the potato tissues.

He after that tried to solidify frequent liquid medium by adding gelatin. Separate bacterial colonies developed after the surface had been streaked with a bacterial sample. When the gelatin method hardened, specific bacteria produced independent colonies. Despite its advantages, gelatin was not a perfect solidifying agent since it was digested by various bacteria and melted when the heat rose above 28°C.

Fannie Hesse suggested a better alternative. She suggested the utilization of agar as a solidifying agent. Agar is derived from red algae. Agar had not been attacked by virtually all bacteria and didn't melt until reaching a temperature of 100°C unlike gelatin.

Richard Petri designed the Petri dish (Plate) in 1887, a container for making solid culture media. This development made possible the isolation of genuine cultures that contained simply an individual microorganism.

Koch and his colleagues are also in charge of many other advances in laboratory microbiology, like the following:

Simple staining approaches for bacterial cells and flagella.

The primary photomicrograph of bacteria.

The 1st photograph of bacteria in diseased tissues.

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

The utilization of steam to sterilize growth media.

The usage of Petri dishes to carry solid growth media.

Aseptic laboratory techniques such as for example transferring bacteria between media using platinum wire that has been sterilized in a flame.

Koch hypothesized that each bacterial colony consisted if the progeny of an individual cell.

Koch use laboratory family pets to inject bacteria and review disease development.

For these achievements, Koch is considered as the Father of the Microbiological laboratory.

Gram's stain

Although Koch reported a simple staining technique in 1877, the Danish scientist Gram designed a far more important staining approach in 1884. His technique which involves the application of group of dyes manufactured some microbes blue and other's crimson. The blue cells will be called the Gram great and the reddish cells are named the Gram negative. We now use Gram Stain to separate bacteria into these two large groups.

The gram stain continues to be the hottest staining technique. It really is among the first steps carried out in any laboratory where bacteria are being identified.

4- How Can We Prevent Infection And Disease?

1- Semmelweis and Hands washing

Semmelweis was a physician started out requiring medical students to wash hands with chlorinated lime normal water.

2- Lister's Antiseptic Technique

Joseph Lister (1867), an English surgeon found indirect proof that microorganism were agents of individual disease. He done the prevention of wound infection. He developed something of antiseptic surgery made to prevent microorganism from getting into wounds. Instruments were heat sterilized and phenol was applied to medical dressings and sprayed over the medical area. He provided a strong evidence for the purpose of microorganisms in disease development because phenol which killed bacteria also prevented wound infections.

3- Nightingale and Nursing

Nightingale was an English nurse and she is the founder of contemporary nursing and she presented cleanliness and antiseptic techniques into nursing practices.

4- Snow and Epidemiology

John Snow an English physician plays a key role ion setting expectations once and for all public hygiene to prevent the pass on of infectious diseases.

His study was the foundation for two branches of microbiology (disease control) and epidemiology (research of the occurrence, distribution and spread of disease in individuals).

5- Jenner's Vaccine

On 1796, Edward Jenner used cowpox-infected material to successfully vaccinate people against human little pox.

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

Jenner invented vaccination or immunization.

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

6- Ehrlich's magic bullets and Chemotherapy

Ehrlich found that chemicals could possibly be used to destroy microorganisms.

He discovered chemicals active against trypanosomes the protozoan that causes sleeping sickness and against Treponema that trigger syphilis. His discoveries commenced the branch of chemotherapy.

The Modern Age of Microbiology

1- How Do Genes work?

Over days gone by 40 yeasts, developments in microbial genetics progressed into several fresh disciplines that happen to be among the faster growing regions of scientific exploration today; including:

Molecular biology.

A- Molecular Biology

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

Molecular biologists are worried with genome sequencing.

A full understating of the genomes of organisms will cause practical methods to limit disease, mend genetic defects and enhance agricultural yield.

B- Recombinant DNA technology

Molecular Biology is used in recombinant DNA technology, normally called genetic engineering that was first developed using microbial products. This consists of the production of human being insulin in genetically designed bacteria.

C- Gene therapy

An exciting new region of study is the utilization of recombinant DNA technology for gene remedy. That is a process which involves inserting a lacking gene or repairing a defective gene in individual cells. This process uses harmless infections to insert a preferred gene into web host cells where it is incorporated right into a chromosome and begins to function normally.

2- What Functions Do Microorganisms Take up in the surroundings?

The study of microorganisms within their natural environment is named environmental Microbiology or microbial ecology.

3- How We Defend Against Disease?

Advancements in chemotherapy had been manufactured in the 1900s with the discovery of several substances such as penicillin and sulfa prescription drugs that inhibit bacteria.

4- The Scope And Relevance of Microbiology

Microbiology has both basic aspects and applied aspects. A scientist employed in the field of microbiology is named a microbiologist. Various microbiologists are enthusiastic about the biology of microorganisms. They could focus on a particular group of microorganisms and are called: Virologist (Virology may be the study of viruses), Bacteriologist (Bacteriology may be the study of bacteria), Phycologist (Phycology is the research of algae), Mycologist (Mycology is the research of fungi), and Protozoologist (Protozoology may be the study of protozoa).

Other microbiologist do the job in other fields such as for example microbial physiology, microbial cytology, microbial ecology, and microbial taxonomy. Other microbiologists have significantly more practical applied fields such as for example medical microbiology, meals and dairy microbiology, and general public health microbiology.

Medical Microbiology: Deals with human and animal diseases.

Agricultural Microbiology: Handles the use of microorganisms in agriculture.

Public health Microbiology: Handles the control of the spread of diseases.

Food and dairy Microbiology: Handles the application of microorganisms by man to make foods such as for example cheese, bread, and different important products.

Industrial Microbiology: Deals with the commercial application of microorganisms like the production of vaccines, antibiotics, vitamin supplements and enzymes.

Microbial Ecology or Environmental microbiology: Deals with the relationship between microorganisms and their environments.

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

6- What Will The Future Hold?

What will microbiologists discover following?

Among the inquiries for the next 50 years are the following:

1- What is the physiology of existence forms that can certainly not be grown in laboratory and only known to us today by their nucleic acid sequences?

2- Does life exist beyond the world, and if so, what exactly are its features?

3- How do we reduce the risk of infectious diseases, especially the ones that can be utilised by bioterrorists?