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
Search for
Structures Swiss-model
Domains InterPro

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, the most commonly used biological pesticide worldwide. 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 moths such as Cadra calidella—in laboratory experiments working with C. calidella, many of the moths were diseased due to this parasite.

<span class="mw-page-title-main">Genetically modified maize</span> 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, color of flowers, growth rate, size of harvested products and resistance to diseases and pests.

<span class="mw-page-title-main">Genetically modified food</span> 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 various 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.

<span class="mw-page-title-main">Genetically modified crops</span> 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 pest resistant plant cotton variety that produces an insecticide to combat bollworm.

<i>Helicoverpa armigera</i> Species of moth

Helicoverpa armigera is a species of Lepidoptera in the family Noctuidae. It is known as the cotton bollworm, corn earworm, Old World (African) bollworm, or scarce bordered straw. The larvae feed on a wide range of plants, including many important cultivated crops. It is a major pest in cotton and one of the most polyphagous and cosmopolitan pest species. It should not be confused with the similarly named larva of the related species Helicoverpa zea.

<span class="mw-page-title-main">Plant Genetic Systems</span> Bayer Subsidiary

Plant Genetic Systems (PGS), since 2002 part of Bayer CropScience, is a biotech company located in Ghent, Belgium. The focus of its activities is the genetic engineering of plants. The company is best known for its work in the development of insect-resistant transgenic plants.

<span class="mw-page-title-main">Genetically modified food controversies</span>

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.

<span class="mw-page-title-main">Genetically modified plant</span> Plants with human-introduced genes from other organisms

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 is most often taken advantage by genetic engineers through selecting cells that can successfully be transformed into an adult plant which can then be grown into multiple new plants containing transgene in every cell through a process known as tissue culture.

<span class="mw-page-title-main">Delta endotoxins</span> Group of insecticidal toxins produced by the bacteria Bacillus thuringiensis

Delta endotoxins (δ-endotoxins) are a family of pore-forming toxins produced by Bacillus thuringiensis species of bacteria. They are useful for their insecticidal action and are the primary toxin produced by the genetically modified (GM) Bt maize/corn and other GM crops. 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 another group of delta-endotoxins formed in the cytoplasm. VIP toxins are formed at other stages of the life cycle.

<i>Chloridea virescens</i> Species of moth

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.

<span class="mw-page-title-main">Genetically modified rice</span>

Genetically modified rice are rice strains that have been genetically modified. Rice plants have been modified to increase micronutrients such as vitamin A, accelerate photosynthesis, tolerate herbicides, resist pests, increase grain size, generate nutrients, flavors or produce human proteins.

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) by forming pores in the digestive system. Mahyco, an Indian seed company based in Jalna, Maharashtra, has developed the Bt brinjal.

<span class="mw-page-title-main">Genetically modified tomato</span> Tomato with modified genes

A genetically modified tomato, or transgenic tomato, is a tomato that has had its genes modified, using genetic engineering. The first trial genetically modified food was a tomato engineered to have a longer shelf life, which was on the market briefly beginning on May 21, 1994. The first direct consumption tomato was approved in Japan in 2021. Primary work is focused on developing tomatoes with new traits like increased resistance to pests or environmental stresses. Other projects aim to enrich tomatoes with substances that may offer health benefits or be more nutritious. As well as aiming to produce novel crops, scientists produce genetically modified tomatoes to understand the function of genes naturally present in tomatoes.

<span class="mw-page-title-main">Cry6Aa</span>

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.>

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.

References

  1. Acharjee S, Sarmah BK (2013). "Biotechnologically generating 'super chickpea' for food and nutritional security". Plant Sci. 207: 108–16. doi:10.1016/j.plantsci.2013.02.003. PMID   23602105.
  2. McLean M (2011). "A review of the environmental safety of the Cry1Ab protein". Environ Biosafety Res. 10 (3): 51–71. doi: 10.1051/ebr/2012003 . PMID   22541994.
  3. Liu YB, Li JS, Zhao CY, Xiao NW, Guan X (2012). "[Occurrence and ecological consequences of transgenic rice gene flow: a review]". Ying Yong Sheng Tai Xue Bao (in Chinese). 23 (6): 1713–20. PMID   22937665.
  4. Choudhary B, Gaur K. 2010. Bt Cotton in India: A Country Profile. ISAAA Series of Biotech Crop Profiles. ISAAA: Ithaca, NY. James, Clive. 2009. Global Status of Commercialized Biotech/GM Crops: 2009. ISAAA Brief No.41. ISAAA: Ithaca, NY.
  5. Mesnage R, Clair E, Gress S, Then C, Székács A, Séralini GE (2013). "Cytotoxicity on human cells of Cry1Ab and Cry1Ac Bt insecticidal toxins alone or with a glyphosate-based herbicide". J Appl Toxicol. 33 (7): 695–9. doi:10.1002/jat.2712. PMID   22337346.
  6. Shipman, Matt (June 1, 2015). "Carolinas field study: Is Bt corn losing against corn earworm?". SouthEast FarmPress.
  7. Ledford, Heidi (July 6, 2009). "Pests could overcome GM cotton toxins: Caterpillars reveal a chink in the armour of transgenic crops". Nature. Springer Nature.
  8. Arya S, Shrivastav S (June 8, 2015). "Seeds of doubt: Monsanto never had Bt cotton patent". The Times of India.
  9. Genetic Literacy Project. The Industry Funding Behind Anti-GMO Activist Gilles-Éric Séralini. June 19, 2015.
  10. Entine J (June 24, 2014). "Profile of Gilles-Éric Séralini, Author Of Republished Retracted GMO Corn Rat Study". Forbes.
  11. Vázquez-Padrón RI, Moreno-Fierros L, Neri-Bazán L, de la Riva GA, López-Revilla R (1999). "Intragastric and intraperitoneal administration of Cry1Ac protoxin from Bacillus thuringiensis induces systemic and mucosal antibody responses in mice". Life Sci. 64 (21): 1897–912. doi:10.1016/s0024-3205(99)00136-8. PMID   10353588.
  12. Rodriguez-Monroy MA, Moreno-Fierros L (2010). "Striking activation of NALT and nasal passages lymphocytes induced by intranasal immunization with Cry1Ac protoxin". Scand. J. Immunol. 71 (3): 159–68. doi: 10.1111/j.1365-3083.2009.02358.x . PMID   20415781.
  13. Pabst R (2015). "Mucosal vaccination by the intranasal route. Nose-associated lymphoid tissue (NALT)-Structure, function and species differences". Vaccine. 33 (36): 4406–13. doi:10.1016/j.vaccine.2015.07.022. PMID   26196324.
  14. Rojas-Hernández S, Rodríguez-Monroy MA, López-Revilla R, Reséndiz-Albor AA, Moreno-Fierros L (2004). "Intranasal coadministration of the Cry1Ac protoxin with amoebal lysates increases protection against Naegleria fowleri meningoencephalitis". Infect. Immun. 72 (8): 4368–75. doi:10.1128/IAI.72.8.4368-4375.2004. PMC   470623 . PMID   15271892.