Classification of microorganisms
Taxonomists categorised microorganisms according to differences in their cell components such as DNA, fatty acids, pigments, antigens, and quinones and their cellular metabolism. Also, they classify cellular microorganisms based on cell structure, genetic origin, and behavioural factors. Vital factors such as DNA, fatty acids, pigments, antigens, and quinones are involved in it.
The classification consists of naming and grouping organisms according to their similarities to describe the diversity of bacterial species. Phylogenetic linkages, or evolutionary links, are the foundation of the present classification.
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There are some techniques used in identifying microorganisms. Microorganism identification capabilities include chromogenic media, microscopic work, and biochemical and molecular technology.
Experts divide all methods into two major groups, namely phenotypic and genotypic identification. A phenotype is the collection of all expressed characteristics of an organism. Phenotypic identification consists of practice focused on components such as morphology, physiology, or biochemical attributes of microorganisms.
Microorganisms tend to have relatively rapid evolution. Most microorganisms can reproduce rapidly, and microbes such as bacteria can also freely exchange genes through conjugation, transformation, and transduction, even among widely divergent species. The horizontal gene transfer coupled with a high mutation rate allows microorganisms to evolve rapidly to adapt to novel environments.
Bacteria, viruses, fungi, protozoa, and algae are some of the broad components of microorganisms. Prokaryotic microorganisms include bacteria and archaea, whereas eukaryotic organisms include protozoa, algae, and fungi.
Experts use advanced (DNA-based) biochemical and phenotypic methods to understand microorganism identification and characterization.
Scientists use the best techniques, such as:
- DNA sequencing may identify bacteria, moulds, and yeasts.
- The Ribo-printer analysis will be helpful for bacterial identification and characterization.
- The repeat-based polymerase chain reaction helps determine the similarity of microorganisms.
- Scientists confirm the rapid pathogen test by a polymerase chain reaction.
What is the process of identifying and characterising microorganisms?
- Identification of microorganisms
Experts use Species and genus names to gauge factors like heat resistance, safety, and spoilage.
- Characterisation of microorganisms (typing)
These groups combine organisms, similar DNA fragment patterns, or antigenic features to locate or trace contamination.
Robert Whittaker, an American biologist, describes the role of the Five Kingdoms classification, and it has based on the following traits:
- The presence of nuclear membranes and the cell type (likewise, prokaryotic or eukaryotic)
- Cell wall and its constituent's presence
- Body structure
- Methodology of nutrition Procedure of reproduction
- Phylogenetic linkages
R. H. Whittaker divided living organisms into five kingdoms. They are as follows:
Monera –Single-cell prokaryotes
Protista – Single-celled r eukaryotes
Fungi-Eukaryotic, heterotrophic (parasitic/saprophytic), and with a cell wall are fungi
Plantae- Eukaryotic, autotrophic (photosynthetic), and have a cell wall (cellulose)
Animalia –heterotrophic (holozoic/saprophytic), eukaryotic, and with no cell wall
The initial, substantial, and broadest classification into which organisms fall is known as a domain.
It has three subgroups:
- Bacteria, Archaea, Eukaryotes
The first group determines whether an organism is a prokaryote or eukaryote. Carl Woese, a physicist and microbiologist, first proposed the domain in 1978. Its foundation is the discovery of commonalities in the ribosomal RNA sequences of bacteria.
It is crucial to comprehend how the three kingdoms of life—Bacteria, Archaea, and Eukaryotes—relate to one another. Most metabolic pathways, which comprise the preponderance of an organism's genes, are prevalent between archaea and bacteria. In contrast, most genes involved in genome expression are common between archaea and Eukarya. The archaeal cell structure is most comparable to gram-positive bacteria among prokaryotes.
Bacteria lack membrane-bound organelles and can function and reproduce as individual cells but often aggregate into multicellular colonies. Their genome is typically just one loop of DNA, but they can also contain tiny DNA fragments called plasmids. Bacterial conjugation can transfer these plasmids across cells. The cell wall that surrounds every bacterial cell offers stability and strength.
- Archaea:
Historically, bacteria and archaea were not distinguished, and experts treated them under the Monera class. The single-celled organisms known as archaea are also devoid of nuclei. The genetic makeup and biochemistry of archaea are distinct from those of bacteria. The phospho-glycerides with ester linkages that support the operation of bacterial cell membranes differ from the ether lipids that make up archaea cell membranes. Archaea are single-celled organisms that lack nuclei. There are genetic and biochemical differences between archaea and bacteria.
Eukaryotes have organelles like the cell nucleus, the Golgi apparatus, and mitochondria in their cells, which collide with bacteria and archaea. Like bacteria, plant cells have cell walls and contain organelles such as chloroplasts, besides the organelles found in other eukaryotes.
Taxonomy is the study of how creatures are categorised, and taxa are the groups that make up the classification system. Taxonomy is the process of classifying novel or previously classified microorganisms. Microorganisms are identified scientifically by binomial nomenclature, which consists of two words for the genus and species. Microbes have Latin names, and it is always necessary to capitalise the first letter of the genus name.
R. H. Whittaker divided living organisms into five kingdoms. Vital factors such as DNA, fatty acids, pigments, antigens, and quinones are involved in the analysis of microorganisms. Phylogenetic linkages, or evolutionary links, are the foundation of progressive allotment. The Gram stain uses the structural hallmark of the cell walls to categorise microorganisms. Researchers divide most bacteria into four types based on their morphology, and Gram-staining results include Gram-positive cocci, Gram-positive bacilli, Gram-negative cocci, and Gram-negative bacilli.
References:
Microorganism identification and characterisation Campden BRI In-text: (Smith, 2022) Smith, J., 2022. Microorganism identification and characterisation Campden BRI. Campdenbri.co.uk. Available at: <https://bit.ly/3QmaDv9> [Accessed 12 August 2022].
Reference List: 1.2B: Classification of microorganisms (2017) Biology Libre Texts. Libre texts. Available at: hthttps://bit.ly/3C0si73. [Accessed2 August 2022].