Cry1Ac

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Cry1Ac
4arx.png
Toxin Cry1Ac from Bacillus thuringiensis ssp. kurstaki HD-73. PDB entry 4arx
Identifiers
Organism Bacillus thuringiensis
SymbolCry1Ac
UniProt P05068

Cry1Ac protoxin is a crystal protein produced by the gram-positive bacterium, Bacillus thuringiensis (Bt) during sporulation. Cry1Ac is one of the delta endotoxins produced by this bacterium which act as insecticides. Because of this, the genes for these have been introduced into commercially important crops by genetic engineering (such as cotton and corn) in order to confer pest resistance on those plants. [1] [2] [3]

Transgenic Bt cotton initially expressed a single Bt gene, which codes for Cry1Ac. [4] Subsequently, Bt cotton has added other delta endotoxins. [5] Products such as Bt cotton, Bt brinjal and genetically modified maize have received attention due to a number of issues, including genetically modified food controversies, [6] [7] [8] and the Séralini affair. [9] [10]

Cry1Ac is also a mucosal adjuvant (an immune-response enhancer) for humans. [11] [12] [13] It has been used in research to develop a vaccine against the amoeba Naegleria fowleri . [14] This amoeba can invade and attack the human nervous system and brain, causing primary amoebic meningoencephalitis, which is nearly always fatal.

See also

Related Research Articles

<i>Bacillus thuringiensis</i> Species of bacteria used as an insecticide

Bacillus thuringiensis is a Gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide. B. thuringiensis also occurs naturally in the gut of caterpillars of various types of moths and butterflies, as well on leaf surfaces, aquatic environments, animal feces, insect-rich environments, and flour mills and grain-storage facilities. It has also been observed to parasitize other moths such as Cadra calidella—in laboratory experiments working with C. calidella, many of the moths were diseased due to this parasite.

Genetically modified maize Genetically modified crop

Genetically modified maize (corn) is a genetically modified crop. Specific maize strains have been genetically engineered to express agriculturally-desirable traits, including resistance to pests and to herbicides. Maize strains with both traits are now in use in multiple countries. GM maize has also caused controversy with respect to possible health effects, impact on other insects and impact on other plants via gene flow. One strain, called Starlink, was approved only for animal feed in the US but was found in food, leading to a series of recalls starting in 2000.

Agricultural biotechnology, also known as agritech, is an area of agricultural science involving the use of scientific tools and techniques, including genetic engineering, molecular markers, molecular diagnostics, vaccines, and tissue culture, to modify living organisms: plants, animals, and microorganisms. Crop biotechnology is one aspect of agricultural biotechnology which has been greatly developed upon in recent times. Desired trait are exported from a particular species of Crop to an entirely different species. These transgene crops possess desirable characteristics in terms of flavor, colour of flowers, growth rate, size of harvested products and resistance to diseases and pests.

Genetically modified food Foods produced from organisms that have had changes introduced into their DNA

Genetically modified foods, also known as genetically engineered foods, or bioengineered foods are foods produced from organisms that have had changes introduced into their DNA using the methods of genetic engineering. Genetic engineering techniques allow for the introduction of new traits as well as greater control over traits when compared to previous methods, such as selective breeding and mutation breeding.

Pesticide resistance

Pesticide resistance describes the decreased susceptibility of a pest population to a pesticide that was previously effective at controlling the pest. Pest species evolve pesticide resistance via natural selection: the most resistant specimens survive and pass on their acquired heritable changes traits to their offspring.

Genetically modified crops Plants used in agriculture

Genetically modified crops are plants used in agriculture, the DNA of which has been modified using genetic engineering methods. Plant genomes can be engineered by physical methods or by use of Agrobacterium for the delivery of sequences hosted in T-DNA binary vectors. In most cases, the aim is to introduce a new trait to the plant which does not occur naturally in the species. Examples in food crops include resistance to certain pests, diseases, environmental conditions, reduction of spoilage, resistance to chemical treatments, or improving the nutrient profile of the crop. Examples in non-food crops include production of pharmaceutical agents, biofuels, and other industrially useful goods, as well as for bioremediation.

Bt cotton is a genetically modified organism (GMO) or genetically modified pest resistant plant cotton variety, which produces an insecticide to combat bollworm.

Genetically modified food controversies Controversies over GMO food

Genetically modified food controversies are disputes over the use of foods and other goods derived from genetically modified crops instead of conventional crops, and other uses of genetic engineering in food production. The disputes involve consumers, farmers, biotechnology companies, governmental regulators, non-governmental organizations, and scientists. The key areas of controversy related to genetically modified food are whether such food should be labeled, the role of government regulators, the objectivity of scientific research and publication, the effect of genetically modified crops on health and the environment, the effect on pesticide resistance, the impact of such crops for farmers, and the role of the crops in feeding the world population. In addition, products derived from GMO organisms play a role in the production of ethanol fuels and pharmaceuticals.

MON 863 is a genetically engineered variety of maize produced by Monsanto. It is genetically altered to express a modified version of Cry3Bb1, a delta endotoxin which originates from Bacillus thuringiensis. This protects the plant from corn rootworm. Unlike MON 810, Bt 11, and Bt 176 which each produce a modified Cry1Ab, MON 863 instead produces a modified Cry3Bb1 toxin and contains nptII, a marker gene for antibiotic resistance.

Genetically modified plant

Genetically modified plants have been engineered for scientific research, to create new colours in plants, deliver vaccines, and to create enhanced crops. Plant genomes can be engineered by physical methods or by use of Agrobacterium for the delivery of sequences hosted in T-DNA binary vectors. Many plant cells are pluripotent, meaning that a single cell from a mature plant can be harvested and then under the right conditions form a new plant. This ability can be taken advantage of by genetic engineers; by selecting for cells that have been successfully transformed in an adult plant a new plant can then be grown that contains the transgene in every cell through a process known as tissue culture.

Delta endotoxin Group of insecticidal toxins produced by the bacteria Bacillus thuringiensis

Delta endotoxins (δ-endotoxins) are pore-forming toxins produced by Bacillus thuringiensis species of bacteria. They are useful for their insecticidal action and are the primary toxin produced by Bt corn. During spore formation the bacteria produce crystals of such proteins that are also known as parasporal bodies, next to the endospores; as a result some members are known as a parasporin. The Cyt (cytolytic) toxin group is a group of delta-endotoxins different from the Cry group.

<i>Chloridea virescens</i>

Chloridea virescens, commonly known as the tobacco budworm, is a moth of the family Noctuidae found throughout the eastern and southwestern United States along with parts of Central America and South America.

The MON 810 corn is a genetically modified maize used around the world. It is a Zea mays line known as YieldGard from the company Monsanto. This plant is a genetically modified organism (GMO) designed to combat crop loss due to insects. There is an inserted gene in the DNA of MON 810 which allows the plant to make a protein that harms insects that try to eat it. The inserted gene is from the Bacillus thuringiensis which produces the Bt protein that is poisonous to insects in the order Lepidoptera, including the European Corn Borer.

The genetically modified brinjal is a suite of transgenic brinjals created by inserting a crystal protein gene (Cry1Ac) from the soil bacterium Bacillus thuringiensis into the genome of various brinjal cultivars. The insertion of the gene, along with other genetic elements such as promoters, terminators and an antibiotic resistance marker gene into the brinjal plant is accomplished using Agrobacterium-mediated genetic transformation. The Bt brinjal has been developed to give resistance against lepidopteron insects, in particular the Brinjal Fruit and Shoot Borer (FSB). Mahyco, an Indian seed company based in Jalna, Maharashtra, has developed the Bt brinjal.

P. Ananda Kumar is an Indian plant molecular biologist and biotechnologist.

Cry6Aa

Cry6Aa is a toxic crystal protein generated by the bacterial family Bacillus thuringiensis during sporulation. This protein is a member of the alpha pore forming toxins family, which gives it insecticidal qualities advantageous in agricultural pest control. Each Cry protein has some level of target specificity; Cry6Aa has specific toxic action against coleopteran insects and nematodes. The corresponding B. thuringiensis gene, cry6aa, is located on bacterial plasmids. Along with several other Cry protein genes, cry6aa can be genetically recombined in Bt corn and Bt cotton so the plants produce specific toxins. Insects are developing resistance to the most commonly inserted proteins like Cry1Ac. Since Cry6Aa proteins function differently than other Cry proteins, they are combined with other proteins to decrease the development of pest resistance. Recent studies suggest this protein functions better in combination with other virulence factors such as other Cry proteins and metalloproteinases.

Nasal- or nasopharynx- associated lymphoid tissue (NALT) represents immune system of nasal mucosa and is a part of mucosa-associated lymphoid tissue (MALT) in mammals. It protects body from airborne viruses and other infectious agents. In humans, NALT is considered analogous to Waldeyer's ring.

India and China are the two largest producers of genetically modified products in Asia. India currently only grows GM cotton, while China produces GM varieties of cotton, poplar, petunia, tomato, papaya and sweet pepper. Cost of enforcement of regulations in India are generally higher, possibly due to the greater influence farmers and small seed firms have on policy makers, while the enforcement of regulations was more effective in China. Other Asian countries that grew GM crops in 2011 were Pakistan, the Philippines and Myanmar. GM crops were approved for commercialisation in Bangladesh in 2013 and in Vietnam and Indonesia in 2014.

Cry34Ab1 is one member of a binary Bacillus thuringiensis (Bt) crystal protein set isolated from Bt strain PS149B1. The protein exists as a 14 kDa aegerolysin that, in presence of Cry35Ab1, exhibits insecticidal activity towards Western Corn Rootworm. The protein has been transformed into maize plants under the commercialized events 4114 (DP-ØØ4114-3) by Pioneer Hi-Bred and 59122 (DAS-59122-7) by Dow AgroSciences. These events have, in turn, been bred into multiple trait stacks in additional products.

References

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