Tag: zoology

Malathion is an organophosphate parasympathomimetic, which binds irreversibly to cholinesterase. Malathion is an insecticide of relatively low human toxicity. Malathion is a parasympathomimetic organophosphate compound that is used as an insecticide for the treatment of head lice. It inhibits acetylcholinesterase activity of most eukaryotes. Malathion is toxic to aquatic organisms, but has a relatively low toxicity for birds and mammals. 

Polychlorinated biphenyls are a group of man-made chemicals useful in a variety of industrial processes, including the insulation and cooling of electrical equipment. But PCB pollution continues long after its source is cut off. PCBs are still found in the Great Lakes through a process called atmospheric deposition. Pollutants like dioxins and PCBs enter from the air into the water through rain and snow, falling particles, and absorption of the gas form of the pollutants into the water.  Dioxins are chemically similar to PCBs. Lake and river sediments are especially good at holding onto PCBs, so bottom-dwelling fish tend to have higher levels.

Herbicide carbamatets are asulam (thiocarbamate), carboxazole, chlorprocarb (phenyl carbamate), dichlormate, fenasulam, karbutilate, terbucarb.

The allethrins are a group of related synthetic compounds used in insecticides.

Atrazine, a triazine herbicide, is used in corn and sorghum for control of broadleaf weeds and grasses. Still used because of its low cost and because it works well on a broad spectrum of weeds common in the US corn belt, atrazine is commonly used with other herbicides to reduce the overall rate of atrazine and to lower the potential for groundwater contamination; it is a photosystem II inhibitor.

Insecticides based on their target sites and mode of action at the target sites can be classified into neurotoxins and others which do not target the nervous system of the insects. Insects have highly specialised interconnected cells nervous system along which electrical charge (impulse) travel. Neurotoxins target the enzymes involved in neurotransmission. The prolonged and irreversible disruption of a normal functioning nervous system may result in death.

Herbicides of photosystem-II inhibit the reduction of plastoquinone at the secondary quinone acceptor site and its subsequent re-oxidation. This consequently light induces charge separation which leads to recombination processes. This process generates reactive oxygen species causing extensive damage in PS II and eventually kills the plant.

Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colourless, tasteless, and an almost odourless crystalline chemical compound, an organochlorine, originally developed as an insecticide, and ultimately becoming infamous for its environmental impacts. Opposition to DDT was focused by the 1962 publication of Rachel Carson's book Silent Spring. It catalogued environmental impacts that coincided with the widespread use of DDT in agriculture in the United States, and it questioned the logic of broadcasting potentially dangerous chemicals into the environment leaving the residues for a long time.

Weedicides or herbicides are weed killers or pesticides used to control weeds in agricultural farms. AMO 1618  or (2-isopropyl-5-methyl-4-trimethylammonium chloride)-phenyl-1-piperidine carboxylate is an  inhibitor of gibberellin biosynthesis which leads to retarded germination. Higher concentrations will lead to  reduced sensitivity of seeds.