Microbiology: The study of microorganisms
Microbiology is the scientific study of microorganisms, which are unicellular or cell-cluster microscopic organisms. These microorganisms include eukaryotes, which have a nucleus, and prokaryotes which do not have a nucleus. Eukaryotes are known as fungi and protists, and prokaryotes are bacteria, protozoa and viruses. Viruses, virions, and prions are not classified as living organisms but are studied by microbiologists. Microbiology allows scientists to explore why some microbes live in a mutual beneficial manner and others become parasitic or pathogenic and cause disease and deterioration.
The history and discovery of microbiology goes way back to 384 BC. Many people, including Aristotle, believed that living organisms could develop from non-living materials. There is much information regarding the history of microbiology, this report will cover the most recognized achievements of scientists. Anton van Leeuwenhoek invented the first single-lens microscope in 1676 and was the first microbiologist to observe bacteria. Many people have said that he was the first microbiologist, but the first recorded microbiological observation was in 1665 by Robert Hooke. He observed the fruiting bodies of molds. It is thought that the founder of the field of bacteriology was Ferdinand Cohn. Cohn was a botanist and his studies of algae and photosynthetic bacteria gave him the ability to describe several bacteria, including Bacillus and Beggiatoa. He was also credited with being the first to formulate a scheme for the taxonomic classification of bacteria. Louis Pasteur and Robert Koch were working at microbiology at the same time as Cohn and are frequently considered to be the founders of medical microbiology. As with the historical microbiology, there are several different types or fields of microbiology. These fields include Microbial physiology, Microbial genetics, Medical microbiology, Veterinary microbiology, Environmental microbiology, Evolutionary microbiology, and Industrial microbiology. The following pages will give more information regarding microbiology and its uses, as well as what each field studies.
Basically, microorganisms are very small organisms or very small living things. Microorganisms can also be referred as, or associated with microbes, micro biota, bugs, germs, viruses, molds, mildews, and slime. As stated previously microbes are organisms that are so tiny they can not be seen without a microscope. Approximately two-thirds of Earth’s living objects is microbial, and are everywhere except when they are deliberately excluded by way of sterilized conditions. The microbes that normally live in or on our bodies are called normal micro biota which is also known as “normal flora”. In contrast microbes that cause infection and infectious diseases are called pathogens, also known as germs.
Microbiology includes the study of living organisms: bacteria or Eubacteria, fungi or Archaeobacteria, protists, archaea, and algae. Organisms that cannot technically be classified as living organisms by conventional definitions are: viruses, virions, prions.
The two types of organisms are eukaryotes and prokaryotes. Eukaryotes are organisms whose cells contain a nucleus and other internal structures which are surrounded by membranes. Prokaryotes do not have a nucleus or other internal structures surrounded by membranes and are mainly bacteria and archaea. Eukaryotes are considered to include protist, algae and fungus.
Algae are a diverse group of protists (simple eukaryotes, containing a nucleus and other internal structures) and most produce their own organic material from sunlight, CO2, and mineral nutrients (photosynthetic). Algel species can range from very tiny single celled species to the plant-like-kelps, with the possibility of reaching tens of meters in length. Most algae that live in extreme conditions are the tiny single-celled species. Algae that are commonly called blue-green algae are actually cyan bacteria, which is a type of photosynthetic bacteria. Algae and cyan bacteria are an important base of the food chain in freshwater and marine ecosystems. These microorganisms perform an ecological role similar to plants in land ecosystems. Without algae there would be little animal life in aquatic habitats. There are times when excessive amounts of nitrate and phosphorus are introduced to freshwater or oceans by fertilizers, and human and livestock sewage. When this happens it creates green appearance in freshwater and red tides in ocean water.
In the area of Bacteria, prokaryotes are included, because the cells lack a nucleus or other internal structures surrounded by membranes. Some bacteria cause disease in humans, plants and animals, but most species are probably not parasites, and harmless. Bacteria are critical to the environment in relation to proper functioning because they decompose dead organisms and therefore recycle organic material back into mineral nutrients.
Archaea like Bacteria includes prokaryotes; they look the same but differ in major genetic and biochemical ways. The genetic differences between these two areas are much larger than all organisms within the domain Eukarya (protists, fungi, plants, animals). Genetically humans may have more in common with a mushroom than bacteria and
archaea. Archaea were discovered and recognized as a distinct domain of life within the last few decades. They have a tendency to adapt to extreme conditions such as very hot or very cold climates (extremophiles). More archaea have been discovered in various habitats in recent years. It is a possibility that archaea have similar roles in the environment as bacteria.
Extremophiles are organisms that are often microbes and live in habitats where one or more environmental conditions are far beyond the toleration of most organisms on Earth. These environments can include heat, cold, pH, ultraviolet radiation, dryness, salt, or toxic chemicals. Studying extremophiles are useful to microbiologists because it helps to understand the how organisms adapt to their environments and how they reproduce or differ in genetics from similar organisms. These organisms also provide models for early life on Earth and how and where we might search for life on other planets. Extremophiles often have unusual physiological and metabolic properties, such as enzymes that can be used in industrial processes under harsh physical or chemical conditions.
Bacteriophages sometimes referred to as just phages, are viruses that survive by infecting bacteria. Phages take over the bacteria’s host’s enzymes and metabolism to make many copies of the virus. During this process, the phages often pick up one or more bacterial genes which may be transferred to other bacteria. This genetic exchange mechanism is called transduction.
There are many areas of study in microbiology, including the following:
Microbial physiology: The study of how microbial cell functions biochemically. This includes the study of microbial growth, microbial metabolism and microbial cell structure.
Microbial genetics: The study of how genes are organized and regulated in microbes in relation to their cellular functions, and are closely related to the field of molecular biology.
Medical microbiology: The study of the role of microbes in human illness, including the study of microbial pathogenesis and epidemiology and is related to the study of disease pathology and immunology.
Veterinary microbiology: The study of the role in microbes in veterinary medicine.
Environmental microbiology: Studying the function and diversity of microbes in their natural environments. This includes the study of microbial ecology, microbially-mediated nutrient cycling, geomicrobiology, microbial diversity and bioremediation.
Evolutionary microbiology: The study of the evolution of microbes, including the study of bacterial systematics and taxonomy.
Industrial microbiology: The exploitation of microbes for use in industrial processes. Examples include industrial fermentation and wastewater treatment. Closely linked to the biotechnology industry. This field also includes brewing, an important application of microbiology.
Microbiology has been around since before 384 BC, and there have been many advances in the field of microbiology. It is true that much is known about this subject, but common estimates suggest that we have studied only about 1% of all of the microbes in any given environment. In contrast to the fact that it has been well over 300 years since the discovery of microbes, this field is in its infancy compared to other biological fields such as: zoology, botany, or entomology (the study of insects).
Microbiology is a very important branch of biological science, and without it many important discoveries would have been missed. Since the discovery of microbes, and the aid of microbiology, bacteria now play an important role as producers of human substances. Microbiology has enabled us to learn how genes function, giving microbiologist the ability to introduce a human gene into a bacterium and have the product of the human gene expressed. Therefore, a hormone called erythropoietin, necessary for the proper development of red blood cells, but extremely difficult to isolate, is now available in high quantity. This hormone has been cloned into bacteria and plenty can be made, purified, and given to people who have no kidneys, since without kidneys this hormone cannot be produced. Human insulin can also be made in a similar way. These examples show the importance of understanding the uses for bacteria and the incredible role of microbiology.
