Glossary of Terms

U.S. Micro-Solutions, Inc. Glossary of Terms

Actinomycetes – A heterogeneous group of morphologically diverse but usually filamentous gram-positive bacteria. They are typically saprobes (in soil) but there are a few pathogenic species that infect humans, animals and plants (e.g., Nocardia, Streptomyces).

Aerobic Bacteria – Solely depends on aerobic respiration (free oxygen) and cannot grow in the absence of oxygen to generate ATP.

AIHA – American Industrial Hygiene Association

Ambient Air – Outdoor air surrounding an object.

Amerospores – Small clear (hyaline) spores that range in size from 3-5 um. When noted microscopically with such methods as spore traps, amerospores cannot be differentiated from Aspergillus/Penicillium conidia or from a myriad of other fungal spore types.

Amplification – Growing microorganisms to great numbers on laboratory agar medium or on inanimate materials.

Anaerobic Bacteria – Microorganisms that are unable to use oxygen to grow and may even be harmed or killed by molecular oxygen.

Antibiotic – A substance produced by microorganisms which inhibits or kills another living mircoorganism; it refers to substances produced by various species of fungi and Actinomycetes.

Antigens – A foreign substance when introduced into the tissues of a vertebrate animal stimulates the production of an antibody.

Antibody – An immunoglobulin (protein) produced by lymphocytes (animal host) in response to a foreign antigen (e.g. bacteria, viruses, or other antigenic substance).

Ascomycota – The largest group of fungi characterized by the formation of asci.

Ascospore – A sexual spore produced in a sac-life structure called an ascus and is characteristic of the phylum Ascomycota.

Asthma – A respiratory disorder of the bronchial tubes or airways; symptoms associated with obstructive airflow characterized by recurring attacks of dyspnea (shortness of breath), wheezing, cough, and tightening of chest. Episodes may be precipitated by inhalation of allergens (e.g. mould) or pollutants (e.g. smoke), infection, cold air, vigorous exercise, or emotional stress.

Bacillus – A common rod-shaped bacterial cellular morphology (e.g. Bacillus anthracis – anthrax).

Bacteria – Microscopically single-celled prokaryotic microorganisms. The bacteria vary morphologically in size and shape, being spherical (coccus), rod-shaped (bacilli), spiral (spirochetes) or comma-shaped (vibrios). The bacteria may be differentiated by the gram stain method (gram-positive or gram-negative).

Basidiospore – A type of sexual spore formed externally on a basidium and is characteristic of the phylum Basidiomycota (e.g., mushroom, smuts, rusts).

Bioaerosol – An airborne organic contaminant that is either generated by or is itself a living organism; examples of bioaerosols are fungi, bacteria, pollen.

Coccus – A common spherical shaped bacterial cellular morphology.

Conidia – Specialized asexual spore generally formed at the apex or side of a specialized sporogenous cell. Conidia are the asexual spores principally of the Ascomycota group of fungi.

Dematiaceous – Presence of dark (dematiaceous) pigmentation within the hyphae or the spores of fungi.

Dust Mites – Microscopic arachnid; ALLERGEN, allergenic proteins derived from dust mites.

EMLAP – Environmental Microbiology Laboratory Accreditation Program, is designed specially for laboratories involved in analyzing microbiological samples to evaluate exposures in a variety of workplaces.

EMPAT – Environmental Microbiology Proficiency Analytical Testing Program designed by AIHA to evaluate environmental laboratories that isolate and identify microorganisms.

Endotoxin – Substance containing lipopolysaccharide complexes found in the cell wall of bacteria; principally gram-negative bacteria; believed to play important role in many complications of sepsis such as toxic shock syndrome, DIC, and thrombocytopenia.

Eukaryotic – An organism whose cells possess true nuclei with a level of cellular organization more complex than that of a prokaryotic organism.

Fungi – Includes filamentous moulds and yeasts that produce fluffy, cottony, wooly, powdery, creamy, or glaborus colonies above the culture medium.

Genus – Comprises different species that have several important features in common but differ sufficiently to still maintain their status as individual species.

Gram-Negative Bacteria – Stain a pink to red color by the gram-stain reaction and due to difference in constituents of bacterial cell walls.

Gram-Positive Bacteria – Stain a blue to purple color by the gram-stain reaction and due to difference in constituents of bacterial cell walls.

HEPA Filter – High-Efficiency-Particulate-Air Filter; designed to remove organisms larger than 0.3 µm from isolation rooms, operating rooms, and biological safety cabinets.

HVAC – Heating, Ventilation, Air Conditioning Unit

Hyaline – Colorless, transparent; e.g., conidia/spore as it relates to moulds.

Hypersensitivity Pneumonitis – (allergic alveolitis) an inflammatory form of interstitial pneumonia that results from an immunologic reaction in hypersensitive individuals. The allergic reaction may be provoked by a variety of microorganisms such as moulds and bacteria.

Hyphae – Tube like projections of basic structural units of mould.

Legionnaires’ Disease – Febrile and acute bacterial pneumonia with numerous clinical presentations chiefly caused by Legionella pneumophila.

Moulds – (Fungi) that produce cottony, wooly, fluffy, powdery aerial growths above the culture medium.

Mycotoxins – Low-molecular-weight secondary metabolic products of filamentous fungi that may affect exposed persons in a variety of ways.

Nosocomial – Health-care associated infections.

Photosynthesis – Process by which green plants and certain other organisms use energy of light to convert carbon dioxide and water into simple sugar (glucose).

Prokaryotic – Organism whose cells do not possess true nucleus.

Relative Humidity – RH, Ratio of the amount of water in the air at a given temperature to the maximum amount it could hold at that temperature; expressed as a percentage.

Saprophytic – Microorganisms that obtain nutrition from dead organic matter and usually do not cause disease in the animal host.

Slime Moulds – Non-phototrophic eukaryotic microbes that have similarity to both fungi and protozoa. Slime moulds live primarily on decaying plant matter such as leaf litter, logs and soil.

Species – Collection of microbial strains that share many common physiological and genetic features and as a group differ notably from other species.

Spore – Small, usually single-celled reproductive body that is highly resistant to dehydration and heat and is capable of growing into a new organism, produced especially by certain bacteria, fungi, algae and nonflowering plants.

Symbiosis – Two or more dissimilar organisms that interact and live together.

Taxonomy – Science of classification.

Virus – Composed of nucleic acid genome surrounded by a protein coat; strict intracellular parasites, reproducing or replicating only within a host cell.

VOC – Volatile Organic Compounds; chemicals containing carbon are called organic. Volatile means they evaporate or get into the air easily which makes them more likely to be inhaled. VOCs are produced by many species of bacteria and fungi and are often accompanied by a foul odor.

Yeasts – Unicellular fungi that reproduce by blastoconidia formation (budding) and sexually by the production of ascospores or basidiospores; produce moist, creamy, opaque or pasty colonies on agar media.

Zygomycetes – A class of fungi that reproduce sexually by fusion of gametangia to form zygospores (eg – Mucor, Rhizopus).

Zygospores – Latent spores, contained in a zygosporangium that results from the fusion of two gametangia.

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