What is DNA?
DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).
The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. The order, or sequence, of these bases determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences.
DNA bases pair up with each other, A with T and C with G, to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix. The structure of the double helix is somewhat like a ladder, with the base pairs forming the ladder’s rungs and the sugar and phosphate molecules forming the vertical sidepieces of the ladder.
An important property of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell.
Deltamethrin is a pyrethroid ester insecticide.Contents |
[edit] Usage
Deltamethrin products are among some of the most popular and widely used insecticides in the world[citation needed] and have become very popular with pest control operators and individuals in the United States in the past five years.[1] This material is a member of one of the safest classes of pesticides: synthetic pyrethroids. While mammalian exposure to deltamethrin is classified as safe, this pesticide is highly toxic to aquatic life, particularly fish, and therefore must be used with extreme caution around water.There are many uses for deltamethrin, ranging from agricultural uses to home pest control. Deltamethrin has been instrumental in preventing the spread of diseases carried by tick-infested prairie dogs, rodents and other burrowing animals[citation needed]. It is helpful in eliminating and preventing a wide variety of household pests, especially spiders, fleas, ticks, carpenter ants, carpenter bees, cockroaches and bedbugs. Deltamethrin is also one of the primary ingredients in ant chalk.
[edit] Malaria control
Deltamethrin plays a key role in controlling malaria vectors, and is used in the manufacture of long-lasting insecticidal mosquito nets. It is used as one of a battery of pyrethroid insecticides in control of malarial vectors, particularly Anopheles gambiae, and whilst being the most employed pyrethroid insecticide, can be used in conjunction with, or as an alternative to, permethrin, cypermethrin and other organophosphate-based insecticides, such as DDT, malathion and fenthion. Resistance to deltamethrin (and its counterparts) is now extremely widespread and threatens the success of worldwide vector control programmes.Recently, in South Africa, residues of deltamethrin were found in breast milk, together with DDT, in an area that used DDT treatment for malaria control, as well as pyrethroids in small-scale agriculture.[2]
[edit] Resistance to deltamethrin
Resistance has been characterised in several important vectors of malaria, including Anopheles gambiae. Methods of resistance include thickening of the cuticle of the vector to facilitate less permeation of the insecticide, metabolic resistance via overexpression of metabolising P450 mono-oxygenases and glutathione-S-transferases, and the kdr sodium channel mutations which render the action of insecticides ineffectual, even when co-administered with piperonyl butoxide. Characterisation of the different forms of resistance has become a top priority in groups studying tropical medicine due to the high mortality of those who reside in endemic areas (Muller, Pie, et al. (2008). Field caught Permethrin-Resistant Anopheles gambiae overexpress CYP6P3, a P450 that metabolises pyrethroids,PLoS Genetics 4(11)).[edit] Poisoning
[edit] In humans
While deltamethrin is easy to use and very effective, it should always be treated with caution. It should be applied according to the instructions that come with the insecticide. When care is not taken, deltamethrin poisoning can occur.Since deltamethrin is a neurotoxin, it attacks the nervous system. Skin contact can lead to tingling or reddening of the skin local to the application. If taken in through the eyes or mouth, a common symptom is facial paraesthesia, which can feel like many different abnormal sensations, including burning, partial numbness, "pins and needles", skin crawling, etc. According to recent medical case reports, chronic exposure to pyrethroid insecticides can cause motor neuron disease.[3]
There are no antidotes, and treatment must be symptomatic, as approved by a physician. Over time, deltamethrin is metabolized, with a rapid loss of toxicity, and passed from the body. A poison control center should be contacted in the event of an accidental poisoning.
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