Microorganism toxicity

The effects of toxic substances are shown in the reduction of numbers of species and quantity of microorganisms. Toxic substances in wastewaters are determined within the framework of biological analysis of water using laboratory tests of toxicity. 

The most widely distributed member of the group of stereoisomers. Of common occurrence in plants and animals. Obt. comly. from phytic acid in com steep liquor. Growth factor for animals and microorganisms. Toxic and lipotropic. Mp 225°. Opt. inactive meso ). 

One of the most important aspects of industrial hygiene is to do with the preparation and serving of food, particularly on offshore facilities where workers are obliged to use the galley for all that they consume. Food can be contaminated by harmful microorganisms, toxic chemicals, poisonous plants, and animals. In order to avoid problems, the following issues should be considered ... 

In regard to water pollution, reports pointed out that water pollutants have the ability to harm aquatic life, threaten human health, or result in the loss of recreational or aesthetic potential. Surface water pollutants come from industrial sources, nonpoint sources, municipal sources, background sources, and other/ unknown sources. Out of the eight chief water pollutants—biochemical oxygen demand, nutrients, suspended solids, pH, oil and grease, pathogenic microorganisms, toxic pollutants, and nontoxic pollutants—all, in one way or another, are linked to chemistry and the chemical industry. 

Plug-flow reactors have a decreasing concentration gradient from inlet to outlet, which means that toxic compounds in the feed remain undiluted during their passage along the reactor, and this may inhibit or kill many of the microorganisms within the... 

Antibiotics are toxic water-solubie compounds produced by molds or bacteria which inhibit the growth of other microorganisms. For an antibiotic to be useful in medicine it should have a high order of selective toxicity to microorganisms which are pathogenic to man. Al-... 

Arsenic is another element with different bioavailabiUty in its different redox states. Arsenic is not known to be an essential nutrient for eukaryotes, but arsenate (As(V)) and arsenite (As(III)) are toxic, with the latter being rather more so, at least to mammals. Nevertheless, some microorganisms grow at the expense of reducing arsenate to arsenite (81), while others are able to reduce these species to more reduced forms. In this case it is known that the element can be immobilized as an insoluble polymetallic sulfide by sulfate reducing bacteria, presumably adventitiously due to the production of hydrogen sulfide (82). Indeed many contaminant metal and metalloid ions can be immobilized as metal sulfides by sulfate reducing bacteria. 

Are the levels of contaminant amenable to bioremediation Are they toxic to microorganisms Are they so abundant that even substantial microbial activity will take too long to clean the site ... 

Spill Disposal In treatment of spills or wastes the suppression of vapors is the first concern and the aquatic toxicity to plants, fish, and microorganisms is the second. Normal procedures for flammable Hquids should also be carried out. 

In general, nonconventional protein foods must be competitive with conventional plant and animal protein sources on the bases of cost delivered to the consumer, nutritional value to humans or animals, functional value in foods, sensory quality, and social and cultural acceptability. Also, requirements of regulatory agencies in different countries for freedom from toxins or toxic residues in single-cell protein products, toxic glycosides in leaf protein products, pathogenic microorganisms, heavy metals and toxins in fish protein concentrates, or inhibitory or toxic peptide components in synthetic peptides must be met before new nonconventional food or feed protein products can be marketed. 

Phytoalexins are low molecular weight compounds produced in plants as a defense mechanism against microorganisms. They do, however, exhibit toxicity to humans and other animals in addition to microbes (30). Coumarins, glycoalkaloids, isocoumarins, isoflavonoids, linear furanocoumarins, stilbenes, and terpenes aU. fall into the category of phytoalexins (31). Because phytoalexins are natural components of plants, and because their concentration may increase as a response to production and management stimuli, it is useful to recogni2e the possible effects of phytoalexins in the human diet. 

Environmentally, these aLkanolamines present little problem. Only AMP has been studied extensively, but it was found to be degradable, to be of low toxicity to fish and microorganisms, and to be nonaccumulative. TRIS AMINO has been added to water used to ship fish in order to improve viabiUty. 

Some quaternary ammonium compounds are potent germicides (164,195,196), toxic in small (mg/L range) quantities to a wide range of microorganisms. 

Trimethyl arsine [593-88-4] C H As, has been identified as the toxic volatile arsenical, once known as "Gosio gas," produced by the reaction of certain molds that grow on wallpaper paste and react with inorganic arsenic compounds present in the paper. A number of microorganisms can methylate arsenic trioxide and other arsenic-containing compounds to yield trimethylarsine. These microorganisms include Scopulariopsis brevicaulis Candida humicola and Gliocladium roseum (72). 

Toxicity to fish is included in the data Hsted in Table 4. Marine life, particularly fish, may suffer damage from spills in lakes and streams. The chlorobenzenes, because they are denser than water, tend to sink to the bottom and may persist in the area for a long time. However, some data indicate that dissolved 1,2,4-trichlorobenzene can be biodegraded by microorganisms from wastewater treatment plants and also has a tendency to slowly dissipate from water by volatilization (34). 

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