Key Points
Key Points
- The study of microorganisms has a very long history with several historical figures such as Hippocrates, Thucydides and Marcus Terentius Varro making observation of the effect of microorganisms and proposing the existence of invisible “minute creatures” in addition to early concepts of immunity, isolation and quarantine.
- The invention of the microscope allowed confirmation of the existence of microorganisms, demonstrated by Antonie van Leeuwenhoek with the development of a lens strong enough to view single-celled organisms. Two hundred years after this advancement Louis Pasteur identified individual microbial strains responsible for fermentation, invented pasteurisation to prevent food spoilage and developed vaccines for disease treatment. At the same time Robert Koch demonstrated disease cause from a single identified microbe. His findings included the specific microorganisms that cause anthrax, cholera and tuberculosis.
- The field of microbiology has continued to develop with several subfields that microbiologists specialise in. These include bacteriology, the study of bacteria; mycology, the study of fungi; protozoology, the study of protozoa; parasitology, the study of helminths and other parasites; and virology, the study of viruses. Also included in the field of microbiology is immunology, the study of the immune system, because host–pathogen interactions are central to the understanding of infectious disease processes. Microbiologists can also specialise in certain areas of microbiology, such as clinical microbiology, environmental microbiology, applied microbiology or food microbiology.
- All three domains of life, Archaea, Bacteria and Eukarya, include microorganisms. Microorganisms in Bacteria and Archaea domains are prokaryotic and lack a nucleus while microorganisms within Eukarya domain are eukaryotic and contain a nucleus. Some microorganisms are not contained within the three domains, such as viruses.
- The human microbiome is important for health and wellbeing, including nutrition and digestion. The microbiome identifies the microorganisms and their genes that live within a particular environment. In humans this microbiome consists of bacteria, archaea, fungi, eukaryotes and viruses and number approximately 1014.
