micro-organism

(noun)

A microorganism (from the Greek: μ, mikrós, "small" and ὀ, organismós, "organism"; also spelled micro-organism, micro organism or microörganism) or microbe is a microscopic organism that comprises either a single cell (unicellular), cell clusters, or multicellular relatively complex organisms.

Related Terms

Examples of micro-organism in the following topics:

  • Antibiotic Discovery

    • Observations of antibiosis between micro-organisms led to the discovery of natural antibacterials produced by microorganisms.
    • More recent observations made in the laboratory of antibiosis between micro-organisms led to the discovery of natural antibacterials produced by microorganisms.
    • After screening hundreds of dyes against various organisms, he discovered a medicinally useful drug, the synthetic antibacterial Salvarsan now called arsphenamine.

  • Control of Nosocomial Infections

    • Two categories of micro-organisms can be present on health care workers' hands: transient flora and resident flora.
    • The first is represented by the micro-organisms taken by workers from the environment, and the bacteria in it.
    • The second group is represented by the permanent micro-organisms living on the skin surface, on the stratum corneum or immediately under it.
    • They are worn to reduce the likelihood the hands of personnel contaminated with micro-organisms from a patient or a fomite (contaminated object) can be transmitted to another patient.

  • Syntrophy

    • A cow eats a lot of grass, the cellulose of which is transformed into lipids by micro-organisms in the cow's large intestine.
    • Yet another example is the community of micro-organisms in soil that live off leaf litter.
    • Such relationships are called reciprocal syntrophy because the plant lives off the products of micro-organisms.
    • These organisms are facultative anaerobes.
    • These reduced organic compounds are generally small organic acids and alcohols derived from pyruvate, the end product of glycolysis.

  • Effects of Drug Combinations

    • This is due to the phenomenon of resistance, whereby a micro-organism gains the ability to resist an antimicrobial drug, while initially the drug effectively slowed the growth of or even killed the target micro-organism.

  • Bacterial Polyesters

    • To produce PHA, a culture of a micro-organism such as Alcaligenes eutrophus is placed in a suitable medium and fed appropriate nutrients so that it multiplies rapidly.
    • Another even larger scale synthesis can be done with the help of soil organisms.
    • Once the population has reached a substantial level, the nutrient composition is changed to force the micro-organism to synthesize PHA.
    • There are also applications for PHA produced by micro-organisms within the medical and pharmaceutical industries, primarily due to their biodegradability.

  • Iron Oxidation

    • Ferric iron (Fe3+) is a widespread anaerobic terminal electron acceptor both for autotrophic and heterotrophic organisms.
    • Electron flow in these organisms is similar to those in electron transport, ending in oxygen or nitrate, except that in ferric iron-reducing organisms the final enzyme in this system is a ferric iron reductase.
    • Model organisms include Shewanella putrefaciens and Geobacter metallireducens.
    • G. metallireducens) can use toxic hydrocarbons such as toluene as a carbon source, there is significant interest in using these organisms as bioremediation agents in ferric iron-rich contaminated aquifers .
    • These micro-organisms (for example Gallionella ferruginea or Leptothrix ochracea) live at the oxic-anoxic interfaces and are microaerophiles.

  • Limitation of Microbial Growth by Nutrient Supply

    • The nutrients used to propagate growth are organism-specific, based on their cellular and metabolic processes. .
    • Essential nutrients are nutrients absolutely required by an organism.
    • Two categories of essential nutrients are macro- and micro-nutrients.

  • Sources of Essential Nutrients

    • Micro-nutrients help enzyme function and maintain protein structure.
    • Organisms usually absorb carbon when it is in its organic form.
    • Carbon in its organic form is usually a product of living things.
    • It is essential to the metabolism of many organisms.
    • Without sufficient phosphate, an organism will cease to grow.

  • RNA Regulation and Antisense RNA

    • Gene regulation, the ability to control whether a gene is expressed or not, is critical in controlling cellular and metabolic processes and contributes to diversity and variation in organisms.
    • There are specific types of RNA molecules that can be utilized to control gene regulation, including messenger RNAs (mRNAs), small RNAs such as microRNAs and lastly, antisense RNAs.

  • Carboxysomes

    • They are proteinaceous structures resembling phage heads in their morphology; they contain the enzymes of carbon dioxide fixation in these organisms.
    • Carboxysomes are an example of a wider group of protein micro-compartments that have dissimilar functions but similar structures, based on homology of the two shell protein families.