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Chimera production.
GMO Modifiers - Resources introduced for Genetic Change.
Forcing Competitors, Enemies, and Strangers into Co-dependency.
Manipulating strengths & conflict to increase Overgrowth.
Addiction uses Deception & Denial to Avoid Responsibility.
GMO Database, EU: http://www.gmo-compass.org/eng/gmo/
COMPANION RESOURCES:
IDENTITY : Becoming a Chimera. ---
HEALTH : Living with & Beyond Mutation.
HOSTS : What is being/has been altered. ---
MODIFIERS : What is/has been used to Mutate.
-Focus-: Monographs on Toxins and Enhancers.
INTRODUCTION: Mutated Combination Incomplete Lifeforms (Chimeras).
INDEX
If you undertake to read the following and make an effort to integrate it such that you can interpret and identify what is RELEVANT for YOU, and perhaps other humans, in general, you will be best to resist attraction to fear, anxiety, paranoia, and hysterics ... which is encouraged by exposure to realities which we are systematically held apart from by the structure of our cultural authority infrastructures including educational, media, news, political, medical, and, pseudo-science boundaries.
That is, if our leaders had expressed a historical optimism in the self-directedness of their membership, and, a humility in their ignorance .. they would NOT have constructed and followed strategies to maintain their membership/voters as dependent, underinformed mental slaves willingly giving over their freedom of health and lifestyle Choices to SYMBOLIC human gods, generally known as experts, scientists, managers, leaders, and, corporations. Your leaders benefit from your accepting their offer of respecting you, as a CHILD, pressed into Dependency, and, without the knowledge to hold them accountable for their many and frequent errors. Allowing them to be irresponsible, while deceiving you with insincere promises and poorly founded good intentions provides them with the Confidence of the authority you sanction in them. Resist the temptation to REACT to sudden awareness with self-terror, and, with the Grace of God, allow the fog of your confusion to drift away and bring you to a discernment of Reality from which you can exercise self-directness.
Pacifier: Plants with Altered Composition.
INDEX
http://www.gmo-compass.org/eng/
agri_biotechnology/breeding_aims/149.plants_altered_composition.html
LINK 2: http://www.rff.org/Publications/WPC/Pages/default.aspx (DOWN)
Most GM plants on the market today are only changed at the production level, e.g. herbicide or pest resistance. ...
Crops for healthier food and feed
- Modified oil content and composition
(e.g. polyunsaturated fatty acids such as linoleic acid, laureic acid) for maize, soybeans, rapeseed and other oil crops: These modified crops could be important in the fight against cardiovascular disease, obesity, and certain forms of cancer.
- "Golden rice" -- enrichment with carotenoids (provitamin A):
This project produced a rice cultivar with enhanced levels of beta-carotene and other carotenoids, which are metabolic precursors of vitamin A. Because rice naturally contains only a negligible amount of beta-carotene, vitamin A deficiency is widespread in regions of the world where rice is a staple food.
- Higher content of protein or amino acids, or modified amino acid composition for enhanced nutritional value: For example, a GM potato was developed in India containing one third more protein including essential, high quality nutrients. The novel gene came from the protein-rich amaranth plant. Another example is LY038, a maize line with enhanced lysine content for improved animal feed quality. It is now awaiting authorisation in the EU.
- Gluten-free wheat:
Celiac sprue patients cannot tolerate the protein gluten (something similar to an allergy).
- Higher levels of beneficial antioxidant compounds
(e.g. lycopene, flavinols found in tomato) to prevent cardiovascular diseases and certain forms of cancer.
- Fruits with longer shelf-life:
The FlavrSavr® tomato is the most famous example.
These tomatoes were the first GM fruit sold in the US and were sold as tomato purée in the UK.
Apples, raspberries and melons with delayed ripening have also been developed.
- Elimination or reduction of undesirable substances like allergens or toxic substances (e.g. caffeine, nicotine).
Crops optimised for industry
- Rather than a mix of different starches, the transgenic "amylopectin potato" contains almost exclusively amylopectin (an increase from 75 to 98 percent). This starch will be used for paper, textiles and adhesives.
- GM rapeseed oil with high erucic acid content is used in plastics and in high-grade industrial lubricants.
The Benefits of Genetically Modified Crops
-- and the Costs of Inefficient Regulation
http://www.rff.org/Publications/WPC/Pages/default.aspx
Matin Qaim, http://www.uni-goettingen.de/de/73908.html
April 2, 2010
Plant genetic engineering methods were developed over 30 years ago, and since then, genetically modified (GM) crops have become commercially available and widely adopted. In 2009, GM crops were being grown on 10 percent of the Earth's arable land.
In these plants, one or more genes coding for desirable traits have been inserted.
The genes may come from the same or another plant species, or from totally unrelated organisms.
The traits targeted through genetic engineering are often the same as those pursued by conventional breeding.
However, because genetic engineering allows for direct gene transfer across species boundaries, some traits that were previously difficult or impossible to breed can now be developed with relative ease.
So-called first-generation GM crops have improved traits.
Herbicide-resistant soybeans and corn (maize), for example, can be "weeded" with herbicides that are more effective, less toxic, and cheaper than the alternatives. Cotton and corn have been modified to incorporate Bacillus thuringiensis (Bt) genes, producing proteins that are toxic only to larval pests. Crops can also be modified to ward off plant viruses or fungi. Even though the seed is more expensive, these GM crops lower the costs of production by reducing inputs of machinery, fuel, and chemical pesticides. In addition, due to more effective pest control, crop yields are often higher.
Important environmental benefits, such as controlling farm runoff that otherwise pollutes water systems, are associated with reduced spraying of chemical insecticides and highly toxic herbicides. Reduced mechanical weeding helps prevent the loss of topsoil. Health benefits result from reduced pesticide exposure for farmers and rural laborers and lower pesticide residues for consumers.
Where Bt crops have been grown in developing countries, the technology appears to often generate employment, because more workers are needed to harvest the significantly higher yields. One study in India suggests that Bt cotton produces 82 percent higher incomes for small-farm households compared with conventional cotton -- a remarkable gain in overall economic welfare.
Recent research shows that direct and indirect effects of Bt cotton increase aggregate welfare by over $2 billion per year in India alone; a significant share of these gains go to rural households living below the poverty line. The annual gains of Bt cotton in China are also estimated in a range of $1 billion. Other developing countries where farmers use Bt cotton include Pakistan, South Africa, Burkina Faso, Mexico, and Argentina.
GM soybeans and corn, which are widely grown in North and South America as well as South Africa and a few other countries, also produce large aggregate welfare gains, currently estimated at $5 billion per year at the global level. Huge benefits are also projected for future GM crops that are more tolerant to drought or more efficient in nutrient use.
In terms of the distribution of benefits, interesting differences can be observed between developed and developing countries. In developed countries, where GM technologies are mostly patented, large profits accrue to biotech and seed companies. In contrast, intellectual property protection is relatively weak in most developing countries, so that GM seed prices are lower and farmers' benefit shares higher. For example, soybean farmers in Argentina or cotton farmers in China and India capture over 70 percent of the overall GM technology benefits. Consumers benefit, too, because new technologies tend to lower the price of food and other agricultural products.
Second-generation GM crops involve enhanced quality traits, such as higher nutrient content.
"Golden Rice," one of the very first GM crops, is biofortified to address vitamin A deficiency, a common condition in developing countries that leads to blindness and entails higher rates of child mortality and infectious diseases. Other biofortification projects include corn, sorghum, cassava, and banana plants, with enhanced minerals and vitamins. Widespread production and consumption of biofortified staple crops could improve health outcomes and provide economic benefits in a very cost-effective way, especially in rural areas of developing countries. A recent simulation shows that Golden Rice could reduce health problems associated with vitamin A deficiency by up to 60 percent in rice-eating populations.
Regulation of GM Crops
Despite all those real and potential advantages, GM crops have aroused significant opposition, particularly in Europe. The major concerns relate to potential environmental and health risks, such as allergenicity of transgenes or loss of biodiversity. But there are also fears about adverse social implications -- for instance, that GM technology could undermine traditional knowledge systems in developing countries -- and the monopolization of seed markets and exploitation of small farmers.
Unexpected risks have not materialized so far, and those risks that do exist seem to be manageable. There is even evidence that GM technology can contribute to the preservation of agrobiodiversity, because the new traits can be inserted into local heirloom varieties. Nevertheless, concerns have led to complex and costly biosafety, food safety, and labeling regulations.
Governments have responsibility for ensuring that foods are safe for consumption and that new agricultural inputs do not damage the environment or harm agricultural production. Most countries require GM products be approved before they may be grown, consumed, or imported. Because approval processes are not internationally harmonized, they have become a major barrier to the spread of GM crops and technologies. For example, the European Union has not yet approved some of the GM corn technologies used in the United States and Argentina, which obstructs trade not only in technologies but also in commodity and food markets.
Often, the regulators are extremely cautious and require extended regulatory trials over many years.
The arduous testing comes at a cost: one estimate puts private compliance costs for approval of a new Bt corn technology in just one country at $6 million to $15 million. Beyond the direct regulatory costs are the indirect costs of forgone benefits -- preventing the use of safe products.
Such high regulatory costs slow down overall innovation rates.
They also impede the commercialization of GM technologies in minor crops and small countries, where markets are not large enough to justify the fixed-cost investments. Expensive regulations discourage small firms, thereby contributing to the further concentration of the agricultural biotech industry.
Reforming Policy
The regulatory complexity appears to be the outcome of the politicized debate and lobbying success of antibiotech interest groups, especially in Europe. Even though genetic engineering does not entail unique risks, GM crops are subjected to a much higher degree of scrutiny than conventionally bred crops. Some reform of GM regulations will be necessary, and economists have an important role in quantifying the costs and benefits.
A "safety rule" approach could be useful here.
It combines a probabilistic risk assessment model with a safety rule decision mechanism and can be employed for cost-benefit and risk-benefit analyses. Its transparent criteria would bring science and objectivity to decisionmaking processes that are often influenced by political economy considerations and a precautionary approach.
Over-regulation has become a real threat to the development and use of GM crops.
Zero regulation is not desirable, either, but the trade-offs associated with regulation -- particularly the forgone benefits for developing countries -- should be considered. In the public arena, the risks of GM crops seem to be overrated, while the benefits are underrated.
Matin Qaim is a professor of international food economics and rural development at Georg-August-University of Goettingen in Germany. His main areas of research include the economics of biotechnology and agricultural research systems, food security and poverty, nutrition and health economics, and modern food supply chains and agricultural markets and policies in developing countries.
Modifier: Agrobacterium tumefaciens.
INDEX
http://www.gmo-compass.org/eng/glossary/38.agrobacterium_tumefaciens.html
Soil bacterium naturally able to transfer parts of its genetic material to plant cells.
It has thus been used as a tool for genetically engineering plants.
Agrobacteria are natural plant parasites.
To create a suitable environment for themselves, they insert genes into plant hosts, which cause them to form a proliferation of cells near the soil level (crown gall). The genetic information for tumour growth is encoded on a mobile, circular DNA fragment (plasmid).
When Agrobacterium infects a plant, it transfers so-called T-DNA to a random site in the plant genome.
The natural ability of Agrobacterium tumefaciens to transfer genes is used in genetic engineering.
The bacterium is used as a means of transporting foreign genes into plants (vector).
To do this, the bacterial T-DNA is cut out of the bacterial plasmid and replaced with the desired foreign gene.
Transferring genes with agrobacteria is a commonly used and reliable method.
It works especially well for dicotelydenous plants like potatoes, tomatoes, and tobacco.
Agrobacteria are less suitable for introducing foreign genes to crops like wheat and maize.
Modifier: Amylose amylopectin starch.
INDEX
http://www.gmo-compass.org/eng/glossary/104.amylose_amylopectin_starch.html
Amylose and amylopectin are different forms of starch.
Plant starch comes in two different forms: amylose (20-30%) and amylopectin (70-80%), each with their own physical and chemical properties:
Amylopectin consists of large, highly-branched molecules, making up the majority of the starch found in plants.
Amylose consists of long, chain-like molecules.
Properties of amylopectin such as water solubility and bonding capacity make it more useful for technical applications in the food, paper, and chemical industries. It is well suited for use in pastes, adhesives, and lubricants. The food industry also takes advantage of its properties.
Usually, amylose and amylopectin must be separated or modified by chemical, physical, or enzymatic means.
For several years, researches have been working on potatoes genetically modified to contain exclusively amylopectin starch. Scientists discovered a gene (GBSS, granular binding starch synthase) that encodes an enzyme directing amylase starch production. This gene can be turned off, thereby interrupting the production of amylose.
Modifier: Bt, Bacillus thuringiensis.
INDEX
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3035146/pdf/bbug0101_0031.pdf
NCBI: Bacillus thuringiensis, A genomics and proteomics perspective. 2010
Mohamed A Ibrahim, Natalya Griko, Matthew Junker, and Lee A Bull, with
the technical assistance of Shweta Biliya and Gayathri Raghupathy.
(See a copy of the original document to view the Figures, noted in the text.)
LINK 2: http://microbewiki.kenyon.edu/index.php/Microbial_Biorealm (MB DOWN)
LINK 3: http://www.gmo-compass.org/eng/agri_biotechnology/
breeding_aims/147.pest_resistant_crops.html (PR DOWN)
LINK 4: http://microbewiki.kenyon.edu/index.php/Bacillus_thuringiensis (MT DOWN)
LINK 5: https://en.wikipedia.org/wiki/Bacillus_thuringiensis (WI DOWN)
LINK 6: http://www.npic.orst.edu/factsheets/BTgen.pdf (NP DOWN)
Bacillus thuringiensis (Bt) is a unique bacterium in that it shares a common place with a number of chemical compounds which are used commercially to control insects important to agriculture and public health. Although other bacteria, including B. popilliae and B. sphaericus, are used as microbial insecticides, their spectrum of insecticidal activity is quite limited compared to Bt. Importantly, Bt is safe for humans and is the most widely used environmentally compatible biopesticide worldwide. Furthermore, insecticidal Bt genes have been incorporated into several major crops, rendering them insect resistant, and thus providing a model for genetic engineering in agriculture.
This review highlights what the authors consider the most relevant issues and topics pertaining to the genomics and proteomics of Bt. At least one of the authors (Lee A Bulla) has spent most of his professional life studying different aspects of this bacterium with the goal in mind of determining the mechanism(s) by which it kills insects. The other authors have a much shorter experience with Bt but their intellect and personal insight have greatly enriched our understanding of what makes Bt distinctive in the microbial world. Obviously, there is personal interest and bias reflected in this article notwithstanding oversight of a number of published studies. This review contains some material not published elsewhere although several ideas and concepts were developed from a broad base of scientific literature up to 2010.
Background and History
The concept and practice of utilizing microorganisms to control insect pests ... in prehistoric times are mentioned in the writings of ancient Egyptian and Chinese scholars. One story relates the practice by gardeners of several Egyptian pharaohs of maintaining bacterial collections for use against insects that attacked and ravaged the gardens surrounding their houses and tomb chapels. Later, in the third century, maladies of insects, most likely occasioned by bacteria, viruses and fungi, were observed. Indeed, Aristotle described in his writings insect diseases such as foulbrood of the honey bee (Apis millifera). Louis Pasteur studied silkworm diseases and differentiated pebrine and flacherie diseases of the silkworm Bombyx mori. Also, Kirby and Bassi made significant contributions to the area of insect pathology, and they, along with Pasteur are considered among the pioneers of infectious disease and pathogenic microbiology.
The era of Bt had its beginning when, in 1901, a Japanese scientist named Shigetane Ishiwata isolated a bacterium from dead silkworm larvae while he was investigating the cause of the so-called "sotto disease" (sudden-collapse disease). The disease was responsible for the loss of large numbers of silkworms in Japan and the surrounding region. Ishiwata named the bacterium Bacillus sotto. A few years thereafter, in 1911, a German scientist Ernst Berliner isolated a related strain from dead Mediterranean flour moth larvae he found in a flour mill in the German state of Thuringia. He appropriately named the organism Bacillus thuringiensis. Berliner studied the bacterium and found inclusion bodies or "Restkorper" alongside the endospore. The year was 1915. Mattes in 1927 again observed the same inclusion bodies in Bt but it was not until much later (25 years) that insecticidal activity was attributed to these highly refractile bodies now referred to as "parasporal crystals," a phrase coined by Christopher Hannay in 1953. Once the significance of the parasporal crystals was realized by Thomas Angus, he promptly demonstrated in the same year the insecticidal activity of the inclusion bodies. And, together with Philip Fitz-James, Hannay in 1955 discovered that the toxic parasporal crystals are composed of protein.
The first commercial insecticide based on Bt, Sporine, was produced in France in 1938 and used primarily to control flour moths. In the United States, Bt was first manufactured commercially in 1958 and, by 1961, Bt-based bioinsecticides were being registered by the US Environmental Protection Agency. Since 1996, insect-resistant transgenic crops, known as Bt crops, have expanded around the globe and are proving to be quite efficient and helpful in reducing the use of chemical insecticides. Latest estimates indicate that more than 50% of the cotton and 40% of the corn planted in the US are genetically engineered to produce Bt insecticidal toxins. The current global market for pesticides (herbicides, insecticides, fungicides, nematicides and fumigants) is valued at $25.3 billion. Biopesticides represent only 2.5% of this market but their share is expected to increase to about 4.2%, or more than $1 billion, in 2010.
Interestingly, some strains of Bt produce non-insecticidal proteins that crystallize into irregular-shaped parasporal inclusions. Inclusions of one isolate treated with protease were toxic to human cancer cells, including leukemic T (MOLT-4) and cervical cancer cells (HeLa). Cytotoxicity was dose-dependent. Another non-insecticidal protein, parasporin, also showed strong cytotoxic activity against MOLT-4 and HeLa cells.
Life Cycle of Bacillus thuringiensis
The life cycle of Bt is characterized by two phases which include vegetative cell division and spore development, otherwise referred to as the sporulation cycle. The vegetative cell is rod-shaped .. and divides into two uniform daughter cells by formation of a division septum initiated midway along the plasma membrane. Sporulation, on the other hand, involves asymmetric cell division and is characterized by seven stages which include (stage I) axial filament formation, (stage II) forespore septum formation, (stage III) engulfment, first appearance of parasporal crystals and formation of a forespore, (stages IV to VI) formation of exosporium, primordial cell wall, cortex and spore coats accompanied by transformation of the spore nucleoid and (stage VII) spore maturation and sporangial lysis.
Figure 1 portrays a fully sporulated cell of Bt in which there are several parasporal crystals lying along side the endospore. The production of crystal proteins by Bt during sporulation is a unique genetically regulated biological phenomenon that, probably, relieves stress physically by offsetting water loss during spore formation and affords an additional survival advantage by exerting lethal action against host insects. In turn, the toxic action provides sufficient host nutrients to allow germination of the dormant bacterial spore and its return to vegetative growth.
Classification and Taxonomy of Bacillus thuringiensis
... vegetative cells of Bt are ... Grampositive, non-capsulated and motile with peritrichous flagella.
Classification of Bt strains ... at least 69 H serotypes and 82 serological varieties (serovars) of Bt have been characterized. H serotyping, however, is limited in its capability to distinguish strains from the same H serotype or from the same serovar. Due to its economic importance, ... numerous Bt strains with activity against lepidopteran, dipteran and coleopteran insects have been isolated. Additionally, Bt strains active against insects belonging to the orders Hymenoptera, Homoptera, Orthoptera and Mallophaga as well as nematodes, mites and protozoa have been isolated.
The placement of Bt as a separate species within the genus Bacillus has been controversial since the publication of The Genus Bacillus in 1973 and Bergey's Manual of Determinative Bacteriology in 1974. The genus Bacillus is one of the most diverse genera in the class Bacilli and includes aerobic and facultatively anaerobic, rod-shaped, Gram-positive spore-forming bacteria with G + C contents ranging from 32-69%. Based on phylogenetic heterogeneity, eight genera in the class Bacilli have been proposed: Bacillus, Alicyclobacillus, Paenibacillus, Brevibacillus, Aneurinibacillus, Virgibacillus, Salibacillus and Gracilibacillus. Many species of these genera are of practical importance because they produce antibiotics and peptides with anti-microbial, anti-viral and anti-tumor activities. They also synthesize thermostable enzymes and molecules that can suppress soil-borne phytopathogenic organisms.
In the monograph The Genus Bacillus, Gordon et al.(1973) considered Bt a variety of B. cereus (Bc) along with B. anthracis (Ba) and B. mycoides (Bm). ... Ba is the causative agent of anthrax, an acute and often lethal disease in humans and animals. Bc is an opportunistic human pathogen and may cause food poisoning, eye infections and periodontal disease, among other ailments. Bt possesses a variety of special features including its (1) ability to live in the environment free and independent from other Gram-positive spore-forming bacilli, (2) production of entomocidal parasporal crystal proteins and (3) survival in a unique environmental niche in the midgut and hemocoel of insects. In addition to Ba, Bc, Bt and Bm, there are two other highly related species B. pseudomycoides (Bpm) and B. weihenstephanensi (Bw) in the BC group.
Curiously, Bt has been alleged to be an opportunistic pathogen in animals and human.(1998/9-2000)
Two Bt strains, Bt 97-27 (subsp. konkukian) and Bt Al Hakam (isolated in Iraq by a United Nations Special Commission), were initially designated as human pathogens. Bt 97-27 was first isolated from necrotic tissue in a twenty-eight year old male hospital patient. The designation of strain 97-27 as Bt was based on biochemical tests and the appearance of inclusion bodies. However, a second isolate from the same patient lacked inclusion bodies. Sequence analysis showed no insecticidal (cry) genes present on the 97-27 chromosome or a lone single plasmid pBT9727. ... To the authors' knowledge, no other studies have been reported that characterize Bt as an opportunistic pathogen of humans or warm-blooded animals.
Genome sequences of a number of strains in the BC group have been completed: Bc (ATCC 14579 and 10987 and strain E33L), Bw-KBAB4, Ba-Ames, Ba-Ames Ancestor and Ba-Sterne. Sequencing and annotation of the genome of Bt subsp. kurstaki is near completion in the Bulla laboratory. Comparison of all the genome sequences, including that of subspecies kurstaki, reveals enormous similarity in terms of nucleotide sequence identity and gene and operon organization, a combination not observed heretofore among different bacterial species. The primary distinguishing features of Bt are its virulence and pathogenicity factors, represented by the insecticidal genes located on the chromosome and several plasmids. Those of Ba are its tripartite toxin and capsule encoded by plasmids only.
... Analysis of various Bc and Bt strains reveal very high diversity in multi-locus genotypes, indicating that Bc and Bt exhibit a low degree of clonality and that exchange of genetic material can occur frequently in their natural environments. ...
Expression and Regulation of Insecticidal Genes
One of the most dramatic aspects of Bt sporulation is the formation of parasporal crystals.
The insecticidal toxins (Cry toxins .. the parasporal crystalline protein of Bt) of Bt, oftentimes referred to as ?4-endotoxins after Heimpel, are somewhat specific to certain insects. The family of genes coding for these toxins is the cry gene family. A common characteristic of cry genes is that they are expressed during the stationary phase of growth. Cry proteins, the end-products of cry gene expression, constitute 20-30% of the cell dry weight and generally accumulate in the mother cell, beginning in stage III of sporulation and continuing through stage VII.
The term ?4-endotoxin, relative to Bt Cry toxin, is a misnomer.
Heimpel named the parasporal crystalline protein of Bt as such because it forms inside the cell and because it is fourth in the order of other toxic components discovered in the bacterium. However, endotoxins are associated with the lipo-polysaccharide moiety of the complete "O" somatic antigen complex found in the outer membrane of various Gram-negative bacteria and are an important factor in their ability to cause disease.
Based on its mode of action, a Cry toxin is a "simple" toxin, which is defined as a monomer or oligomer of a toxic simple protein. A Cry toxin exists as a toxic monomer capable of oligomerization. ... the processing of protoxin to toxin is different among the respective toxin groups, depending on host specificity, i.e., toxins that kill moths, beetles or mosquitoes. For example, Cry1A and Cry4 toxins (--65 kDA) that primarily kill moths and mosquitoes, respectively, are the products of protoxins in the molecular weight range of 125-135 kDa whereas Cry3 toxins (--68 kDa) that kill beetles are conversion products of 72-kDa protoxins. ...
Regulation of cry gene expression at the post transcriptional level may depend on mRNA stability.
The half-life of cry mRNA is approximately ten minutes, which is at least five-fold greater than the half-life of an average bacterial mRNA. ...
One interesting feature of cry genes is their high degree of plasticity.
This particular characteristic may contribute to the versatility of Cry toxins as it relates to their insect host range. ... transposable elements may facilitate gene multiplication and evolution of new toxins. Furthermore, the fact that cry genes are carried on transmissible plasmids increases the likelihood of horizontal gene transfer among different Bt strains, which leads to the creation of new strains with different sets of Cry toxins. ...
Biochemistry and Functional Proteomics of Cry Toxins
Once a mature spore is formed, both the spore and parasporal crystal are released from the mother cell into the environment where they are readily available for larval consumption. The Cry toxin contained in the crystal is the virulence factor that truly distinguishes Bt from its genetic cousins Ba and Bc. And, it is the Cry toxin that establishes safe harbor for the bacterium in an insect carcass. Different parasporal crystals are made either of single or multiple Cry proteins. For example, the parasporal crystal of Bt subsp. kurstaki HD-73 contains Cry1Ac protein only, whereas the parasporal crystal of HD1 strain, which belongs to the same subspecies, is comprised of five different Cry toxins -- Cry1Aa, Cry1Ab, Cry1Ac, Cry2Aa and Cry2Ab.
Another feature of Cry toxins is that their precursor protoxins co-crystallize in various forms and shapes as evidenced by electron microscopy. Cry toxins are encoded by cry genes found mainly on large plasmids. However, the genes may be integrated into the chromosome. Since the cloning and sequencing of the first cry genes, nucleotide sequences have been reported for more than 300 cry genes. ...
Cadherins as Cognate Receptors for Cry Toxins
The receptor molecules that serve as targets for Cry toxins are cadherins and are localized in the midgut of insects. Cadherins belong to a large family of calcium-dependent transmembrane glycoproteins which are highly diverse and multi-functional. Several key functions include cell-cell adhesion, cell migration, regulation of tissue organization and morphogenesis. Cadherins also are involved in signal transduction pathways and interact with other cell adhesion molecules through their ectodomain and with specific cytoplasmic proteins via their cytoplasmic domain. ... The functional relevance of midgut-specific cadherins in insect larvae is manifested in their involvement in controlling cell growth, cell division and cell death through various signaling pathways. ...
Cadherins serve as Cry toxin receptors on midgut epithelial cells in a variety of insects, including the tobacco hornworm, tobacco budworm, silkworm, cotton bollworm, pink bollworm, European corn borer, western corn rootworm, yellow mealworm beetle and mosquito. Recently, Mohamed Ibrahim and Natalya Griko (Bulla laboratory) characterized a cadherin molecule (BT-R3) in Anopheles gambiae, the primary mosquito vector of malaria, and demonstrated that, once bound to the Cry4Ba toxin, death ensues in insect cells transfected with the BT-R3 cDNA (Ibrahim M and Griko N, unpublished data).
...
Cadherins are comprised of repeating calcium-binding cadherin repeats of approximately 110 amino acids in length. The ectodomain of cadherins can range from five cadherin repeats in classical cadherins to as many as thirty-four. Cry toxin-binding cadherins from different insect orders, share a structure composed of four domains: ectodomain (EC), membrane proximal extracellular domain (MPED), transmembrane domain (TM), and cytoplasmic domain (CYTO) (Fig. 5). ... Toxinbinding regions (TBRs) have been identified for cadherins representative of three major insect orders: Lepidoptera (moths, skippers and butterflies), Coleoptera (beetles) and Diptera (mosquitoes and black flies, among others). All of the TBRs are located within those EC modules positioned at or near the MPED, suggesting that this particular area of the cadherin molecule is critical not only for toxin binding but for mediating toxin action as well.
... The structural features of the TBRs on all three BT-Rs most likely are critical to the specificity, selectivity and affinity of their cognate toxins. And, apparently, the signaling events that lead to cell death depend on binding of Cry toxin to the conserved motifs in EC11 or EC12.
Mechanism of Cry (parasporal crystalline protein) Toxin Action
Just as the classification and taxonomy of Bt remains somewhat controversial, so does the explanation of how Cry toxins destroy insects. There are several models reviewed in the literature that seek to explain how Cry toxins exert their killing capacity. For sake of brevity, we have chosen to describe only two mechanisms. The first one postulates that Cry toxin binds to midgut receptor(s), oligomerizes and inserts into the membrane to form lytic pores. ... studies of mutated Cry toxins demonstrate that neither toxin oligomers nor commensurate changes in membrane vesicle permeability correlate directly with toxicity.
The second model (Fig. 7) advanced by Zhang et al. challenges the notion that Cry toxin kills cells exclusively by osmotic lysis. Instead, toxin monomer binds to the cadherin receptor BT-R1 and activates a Mg2+-dependent signal-transduction pathway (peristaltic paralysis?) leading to cell death. ... Cry toxin action is a complex, dynamic process that involves univalent binding of toxin to the highly conserved structural motif (described above) in the cadherin receptor BT-R1. In turn, a cascade of events is triggered that leads to a form of programmed cell death referred to as oncosis. Binding of Cry1Ab toxin to the BT-R1 receptor ... stimulates heterotrimeric G protein and adenylyl cyclase with an accompanying dramatic increase in production of cAMP. The cAMP activates protein kinase A, bringing about an array of cellular alterations, which includes cytoskeletal rearrangement and ion fluxing. Acceleration of this second messenger pathway alters the chemistry of the cell and brings about cell death. Furthermore, the killing mechanism involves promotion by the toxin of exocytotic translocation of BT-R1 from intracellular membrane vesicles to the cell membrane (modified cell membrane permeability?) (potential hydrophobic interactions involving surface-exposed Phe440 in Cry1Ab and Leu1358, Tyr1453 and Val1455 in the TBR of BT-R1). Movement of the receptor is mediated by toxin-induced signal-transduction, and amplification of this signaling (to hypersensitivity -- over-reactivity?) is correlated directly to the execution of cell death. ...
Insect Resistance to Cry Toxins
For the past 50-60 years, commercial formulations of Bt have been utilized to control economically important insect pests worldwide. Today, a number of agricultural crops carry CRY genes that render them resistant to insect infestation. Because the bacterium has co-existed and co-evolved with insects for millions of years, it was assumed that insects would not develop resistance to Bt or its insecticidal toxins. Furthermore, it has been taken for granted that Bt can adapt to an insect's defense system simply by altering the toxins produced to fit the situation or by generating several different toxins with varying specific activities. Although co-evolution and adaptability are relevant factors, interference with nature by questionable management practices involving widespread and intensive use of Bt and its CRY genes has increased the likelihood of insects developing resistance to Bt-based bioinsecticides and transgenic plants. In other words, strong evolutionary pressure on insects by Bt will promote development of defense mechanisms that can circumvent bacterial and toxin attack. In fact, a number of different Bt-resistant insect species have been generated in the laboratory through special selection techniques or have been discovered naturally in the field.
The insecticidal activity of CRY toxins involves a number of sequential events, including dissociation of the parasporal crystals into protoxins, activation of the protoxins to toxins by gut proteases, interaction of the toxins with midgut epithelium and binding to specific receptors. Toxin-receptor interactions trigger a cAMP-dependent signaling pathway, which leads to disruption of the structure and functionality of the midgut epithelium (Fig. 7). When in continual touch with Bt, insects exhibit physiological changes and enhanced immune response. The upshot is resistance to the insecticidal activity of Bt. ... A heightened immune response primarily involves changes in the activity of the mucosal surface, causing increased secretion of proteases and pro-coagulants (Fig. 10A). ... has been shown to bring about precipitation of the protoxin of Bt subsp. sotto. Precipitation leads to sequestering of the toxin and limiting its accessibility to its target receptor. ...
Future Considerations
... the pathogenicity of Bt involves targeting specific cadherin receptors within susceptible hosts, indicating that attacking cell adhesion molecules is evolutionarily significant for Bt and many other pathogens that disrupt and penetrate epithelial barriers in their hosts. ... Also, fathoming insect immunity a la Bt infections would enlighten us about vertebrate immunity as well because insects are similar in a number of ways to vertebrates in their ability to ward off disease. ...
Bacillus thuringiensis, 2011
From
MicrobeWiki, the student-edited microbiology resource,
http://microbewiki.kenyon.edu/index.php/Microbial_Biorealm
LINK 2: http://microbewiki.kenyon.edu/index.php/Bacillus_thuringiensis
Edited by Ernest Hsu of Rachel Larsen and Kit Pogliano
COMMENT: The article has been written and edited by students imprinted with human authority attitudes of confidence in dramatic simplicity, unquestioned acceptance of previous research, an attraction towards the use of absolute statements, and, a reverence for the assumed legitimate leadership and concern of political institutions. This attitude of pride and dissociation has largely been excluded from the below quote, yet will be found in the original. Hypocritical logic is best discerned .. as in "insect and vertebrate immune systems may share some dynamics" and, the absolute that because the BT toxins have been proven (consistently demonstrated) to kill insects ... they must be safe for humans (on which there have been no tests, especially with similar administered concentrations of the BT toxin.
Classification
Eubacteria (kingdom); Bacteria (domain);
Firmicutes (phylum); Bacilli (class); Bacillales (order); Bacillaceae (family);
Bacillus (genus); Bacillus cereus group; Bacillus thuringiensis (species)
... Many studies indicate and consider B. thuringiensis and B. cereus to be one species.
However, their phenotypes greatly differ in that Bt produces crystal proteins despite the fact that crystal protein synthesis is controlled by plasmid genes which can be susceptible to loss and transmission to related bacteria. One response is that Bt strains produce enterotoxins (toxins released by micro-organisms in the lower intestine) that are involved in B. cereus pathogenesis and therefore signifies a fine-line between the two species. ...
Most research has been focused on the Cry toxin crystals. ...
The optimal condition for the Cry toxin to grow and sporulate is in the insect's alkaline gut. ...
It is a soil bacterium and thrives at body temperature. ...
When exposed to higher temperatures such as sunlight (UV light), however, its half-life greatly decreases to around 3.8 hours. As soon as it is exposed to a warmer-than-normal medium, B. thuringiensis' spores start deteriorating and lose viability within four days. Normally, a short half-life is bad. But in Bt's case, it is actually good in that the short half-life minimizes insect resistance. ...
Here is a rough process on how B. thuringiensis causes disease.
B. thuringiensis is digested and the toxins are mixed with the high pH (basic conditions) to bind specific receptors in the gut to attack the host insect. This process punches holes in the gut-lining and thus, the insect becomes weak. As the gut is continuing to break down, spores begin to germinate from the toxic crystals and other bacterial pathogens start to infect the host. B. thuringiensis spores are continuously weakening the host and the insect dies soon thereafter. ... All Cry variants follow a similar two-phase mechanism when infecting the host: 1.) solubilization and 2.) proteolytic activation in the gut and binding to the intestinal cells with pore formation. ...
China is becoming a world-leader in isolating new Bt genes worldwide.
Since 1997, Chinese researchers have isolated and discovered 50 new Bt genes.
Recently, Chinese scientists have been analyzing the cry8-type genes, which were toxic to a number of colopteran pests and certain scarab species. Researchers used PCR-RFLP (Restriction Fragment Length Polymorphism - a technique in which organisms may be differentiated by analysis of patterns derived from cleavage in their DNA). Researchers created a clone, labeled it cry8Ca2, and compared the clone with the known cry8Ca1 gene. Although both genes only differed by one amino acid, the biggest difference was a high toxcitiy towards larvae of the scarabaeid insects Anamala exoleta and Anomala corpulenta. ...
Pest Resistant Crops, 2006
INDEX
LINK 3: http://www.gmo-compass.org/eng/
agri_biotechnology/breeding_aims/147.pest_resistant_crops.html
Insect attack is a serious agricultural problem leading to yield losses and reduced product quality.
Insects can cause damage both in the field and during storage in silos. Each year, insects destroy about 25 percent of food crops worldwide. The larvae of Ostrinia nubilalis, the European corn borer, can destroy up to 20 percent of a maize crop. ...
Bacillus thuringiensis, or Bt, is a ... soil bacterium produces a protein that is toxic to various herbivorous insects. The protein, known as Bt toxin, is produced in an inactive, crystalline form.
When consumed by insects, the protein is converted to its active, toxic form (delta endotoxin), which in turn destroys the gut of the insect. Bt preparations are commonly used in organic agriculture to control insects, as Bt toxin occurs naturally and is completely safe for humans (in soil concentrations of non-modified gene integrity).
More than 100 different variations of Bt toxin have been identified in diverse strains of Bacillus thuringiensis. The different variations have different target insect specificity. For example, the toxins classified under Cry1a group target Lepidoptera (butterflies), while toxins in the Cry3 group are effective against beetles.
Researchers have used genetic engineering to take the bacterial genes needed to produce Bt toxins and introduce them into plants. If plants produce Bt toxin on their own, they can defend themselves against specific types of insects. This means farmers no longer have to use chemical insecticides to control certain insect problems.
(2006) Bt crops have been planted commercially for more than eight years.
Other naturally occurring insecticidal compounds are now becoming available as alternatives to the Bt approach. Among these are chitinase, lectins, alpha-amylase inhibitors, proteinase inhibitors, and cystatin. Plants genetically modified to express these defense proteins are still in early stages of development.
Modifier: Cyanophycin.
INDEX
http://www.gmo-compass.org/eng/glossary/
LINK 2: http://www.gmo-safety.eu/en/potato/nutrition/675.docu.html (Potatoes)
A storage protein produced by cyanobacteria (blue-green algae) and some other bacteria.
Cyanophycin consists of polyaspartate und arginine, two non-toxic, biodegradable raw materials that have a wide variety of industrial uses. Polyaspartate can be used instead of acrylic-acid-based plastics. Until now these two amino acids have been chemically synthesised in small quantities for industrial applications.
It is thought that by introducing the gene for cyanophycin synthesis -- the enzyme that produces cyanophycin -- into potatoes, it will be possible to obtain polyaspartate and arginine more cheaply and on a larger scale.
Modifier: Fructan.
INDEX
http://www.gmo-compass.org/eng/glossary/1.fructan.html
Fructans is a collective term for a group of polysaccharides that consist almost exclusively of linked fructose subunits.
Inulins;
- compounds mainly produced in chicory, onion, jerusalem artichoke, and garlic; count among fructans.
Inulins are indigestible fibres that promote the growth of certain bacteria in the digestive tract.
They are said to have positive health effects and are even implicated in disease prevention (prebiotic effects).
Today, inulins and other polyfructoses, usually extracted from chicory, are used in yogurts and other dairy foods to enhance their nutritional value (functional foods).
Genetic engineering research is going on to modify potatoes and sugar beets to produce higher amounts of (fructan) inulins.
Modifier: Protoplast fusion.
INDEX
http://www.gmo-compass.org/eng/glossary/103.protoplasts.html
Protoplasts (are) Plant cells that have been stripped of their cell walls.
If plant cells are freed from their cell walls, they take on a spherical shape.
Cells are suspended in solutions with carefully adjusted osmotic pressures to keep the cells from bursting.
Certain chemical or electrical stimuli can be used to induce protoplasts to fuse and thereby randomly exchange genetic information (protoplast fusion). Oftentimes, cells of different species can be fused, e.g. tomatoes and potatoes. However, it is rarely possible to regenerate entire plants from such hybrids.
Genetic engineering is different because it involves the transfer of individual, known genes.
Modifier: Somaclonal variation.
INDEX
http://www.gmo-compass.org/eng/glossary/102.somaclonal_variation.html
Somaclonal Variation: Spontaneous changes in the properties of plants being cultured in vitro.
There are many reasons for spontaneous somaclonal variation.
The causes can include point mutations, loss of genes, and chromosomal rearrangement.
They may express themselves by altering traits controlled by many different genes (polygenic).
Somaclonal variation can be used for plant breeding.
Positive effects of somoclonal variation are nevertheless often accompanied by undesirable mutations.
Varieties developed by somaclonal variation exist for tomatoes, potatoes, sugar cane and others.
Somaclonal variation can potentially occur when plants are being regenerated from selected, successfully genetically transformed cells.
Processes: Androgenesis.
INDEX
http://dev.gmo-compass.org/eng/glossary/
Development of an organism with only paternal genes
Some plant species, e.g. tobacco, barley, potatoes, rape, and wheat, can produce haploid plants (plants with only one set of chromosomes) from unripe pollen (haploid androgenesis). This technique is used in conventional plant breeding to produce fully homozygous, double haploid strains (haploid breeding). Ova can also be used as the source material, although this is more unusual (haploid parthenogenesis).
In animals, androgenesis is understood to mean an experimental development of an embryo from a fertilised egg from which the nucleus has been removed. The embryo therefore contains only paternal genes. Techniques like this are used in fish breeding, for example.
Processes: Biopolymers.
INDEX
http://dev.gmo-compass.org/eng/glossary/
Polymers that occur in nature (macromolecules)
Biopolymers are the basic building blocks of living organisms.
Examples of biopolymers are proteins, which are made up of amino acids, the nucleic acids DNA and RNA, which are made up of nucleotides, and polysaccharides such as starch and cellulose.
Biopolymers can be used to produce bioplastics.
For this they are usually modified chemically using technical procedures. The basic materials usually used for bioplastics are currently starch and cellulose. Plants like maize and potatoes are increasingly being grown as renewable raw materials to supply these basic materials.
Processes: Clones.
INDEX
http://www.gmo-compass.org/eng/glossary/174.klonen.html
Genetically identical organisms that arise from asexual reproduction
In nature there are many examples of clones, which are named after the Greek word for 'twig' or 'branch', e.g. protozoa such as bacteria and yeasts, which reproduce through duplication. Sponges propagate by constricting off parts of the organism, also known as budding. Many types of plants, such as strawberries or potatoes, propagate through side shoots, or runners, thereby cloning themselves.
Many plants are easy to clone since they possess the natural ability to regenerate from nearly all tissues, i.e. a complete plant can be grown from, for example, a piece of leaf, and will be genetically identical to it.
The first man-made cloned animal was generated already at the beginning of the last century.
However, it was not until 1996, with the birth of the cloned sheep Dolly, that cloning attracted the public eye.
Until then, clones were produced from embryonal stem cells, which still possess their original ability to develop (totipotency). Dolly was the first mammal to be cloned through a special technology (nuclear transfer) from an already differentiated adult cell.
Processes: Haploid breeding.
INDEX
http://dev.gmo-compass.org/eng/glossary/215.haploid.html
Production of homozygous lines.
Crop plant breeders strive to produce homozygous or true-breeding lines.
The desired trait will be carried through unchanged to subsequent generations only if the trait is present in homozygous form (i.e. having two identical alleles for a given trait).
To obtain a homozygous breeding line, the breeding line would have originally been developed by self-pollination over six to eight generations, which is a very time-consuming and costly process.
Nowadays homozygous lines of some plant species (e.g. tobacco, barley, potatoes, rape and wheat) can be produced from gametes, which contain only one set of chromosomes (haploid). In most cases unripe pollen is placed on a suitable culture medium, where it develops into plants with a single set of chromosomes (haploid androgenesis). Ova may also be used as the source material, although this is less common (haploid parthenogenesis).
Following a cultivation period of three to four weeks, the haploid plantlets are treated with colchicine, a toxin found in meadow saffron. Colchicine inhibits cell division: duplication of the chromosomes occurs, but the subsequent division into two daughter cells is suppressed. The resulting cells produce "double haploid", fully homozygous plants which produce identical offspring.
Processes: Interbreeding.
INDEX
http://
Rapeseed
The interbreeding of rapeseed with wild species:
The pollen of rapeseed comes into contact with several related wild species that are compatible breeding partners. A wild plant known as turnip rape is likely to produce viable hybrid offspring with rapeseed. Wild cabbage and various species of wild mustard are compatible with rapeseed, but viable hybrids are less likely.
Herbicide resistant weeds:
The appearance of herbicide resistant weeds due to the movement of genes from transgenic rapeseed is considered possible. Whether or not herbicide resistance genes become established in wild relatives depends on whether or not these genes offer an advantage to the plant within a certain ecosystem.
The study also revealed that the wild relatives of rapeseed are all very closely related, and it is not yet clear exactly where the limits to breeding compatibility lie. To shed more light on this issue, the EEA study suggests that gene movement (not of GM origin) between different species and populations of rapeseed relatives be investigated. Projects addressing this question are currently underway in several European countries.
Sugar beet and maize.
Maize has no wild relatives in Europe at all, making out-crossing with naturally occurring plants little cause for concern. With sugar beets, on the other hand, out-crossing to wild relatives has already been observed. Genes from cultivated sugar beets were found in the gene pool of a wild, coastal beet population in northeast Italy. The region is home to many sugar beet breeding facilities.
Wheat and barley, being primarily self-pollinated, are not likely to out-cross.
Furthermore, no wild relatives have been identified in Europe that could produce reproductively viable hybrid offspring.
Potato:
The movement of genes between potato plants or from potatoes to wild species is extremely unlikely.
Potatoes reproduce by tubers. Any pollen that makes its way to another plant does not affect the makeup of the plant's tubers and therefore is not passed on to future generations. It is theoretically possible that some transgenic seeds could be produced from cross pollination events, but potato seeds, as a general rule, do not survive under field conditions. Although wild relatives of potatoes do exist in Europe, none of them are known to be sexually compatible.
Out-crossing not necessarily a problem.
Whether or not an out-crossing event with a transgenic plant has environmental or economic consequences does not just depend on the respective crop. It also has a lot to do with the specific trait associated with the transferred gene. Genes that could confer some kind of fitness advantage need to be looked at more critically than genes that appear to be neutral in this respect.
Prospective ecological consequences of an out-crossing event need to be assessed on a case-by-case basis. The out-crossing of an herbicide resistance gene to a wild relative should not be considered particularly important, because herbicide is rarely used outside of the field or the farm. Therefore, an herbicide resistance gene is of no real advantage to a wild plant. In fact, herbicide resistant weeds are already quite common on European farms. This has nothing to do with genetic engineering. These weeds spread their genes when they reproduce, which does not seem to have ecological consequences.
Insect resistant rapeseed would be an entirely different question.
Wild plants that are spared attack from insects could conceivably be more productive, possibly giving them a competitive edge. Whether crops with improved insect resistance are transgenic or bred traditionally should not necessarily be the decisive factor for determining if they merit an environmental impact assessment.
Consensus documents for standardised safety assessment.
The OECD (The Organisation for Economic Cooperation and Development) has issued "consensus documents" for the world's most important crops. The documents describe the crops' biology and the location of naturally existing wild relatives that constitute compatible breeding partners. The purpose of these documents is to provide a degree of uniformity and standardisation on an international level for the safety evaluation of transgenic crops.
Processes: Viral Biorealm.
INDEX
http://microbewiki.kenyon.edu/index.php/Viral_Biorealm
Below is an index Resource of LINKS to pages of Viral Groups as per Classifications.
This can give a starting point to an awareness of the many forms/types of Viruses which are being considered for bioengineering enabling and enhancement.
Contents
- Group I : Double-stranded DNA viruses
- Group II : Single-stranded DNA
- Group III: Double-stranded RNA
- Group IV : (+) Sense single-stranded RNA viruses
- Group V : (-) Sense single-stranded RNA viruses
- Group VI : RNA Reverse Transcribing Viruses (Retroviruses)
- Group VII: DNA Reverse Transcribing Viruses (Pararetroviruses)
Group I. Double-stranded DNA viruses
Replicate using host or viral DNA polymerase.
Non-enveloped bacteriophages:
Myoviridae
Siphoviridae
Tectiviridae
Archaeal viruses:
Ampullaviridae
Bicaudaviridae
Fuselloviridae
Globuloviridae
Guttaviridae
Lipothrixviridae
Rudiviridae
Non-enveloped animal viruses:
Adenoviridae
Papillomaviridae
Phycodnaviridae
Iridoviridae
Enveloped animal viruses:
Herpesviridae
Poxviridae
Baculoviridae
Group II. Single-stranded DNA
Genome consists of (+) sense DNA. Requires a host DNA polymerase to generate the complementary strand.
Non-enveloped.
Non-enveloped bacteriophages:
Inoviridae
Non-enveloped animal viruses:
Parvoviridae
Circoviridae
Circovirus
Non-enveloped plant viruses:
Geminiviridae
Group III. Double-stranded RNA
Requires viral RNA-dependent RNA polymerase; usually packages the polymerase before exiting host cell.
Non-segmented, enveloped, bacteriophage:
Cystoviridae
Segmented, non-enveloped, animal and plant hosts:
Reoviridae
Orthoreovirus
Rotavirus
Birnaviridae
Varicosavirus
Group IV. (+) Sense single-stranded RNA viruses
Require viral RNA-dependent RNA polymerase to generate (-) template for progeny (+) genome.
Usually non-segmented.
Non-enveloped bacteriophages:
Leviviridae
Non-enveloped animal and plant viruses:
Bromoviridae
Bromovirus
Tombusviridae
Tombusvirus
Picornaviridae
Aphthovirus
Enterovirus
Hepatovirus
Rhinovirus
Tobamovirus
Potyviridae
Potyvirus
Enveloped animal and plant viruses:
Coronaviridae
Coronavirus
Flaviviridae
Hepacivirus
Flavivirus
Togaviridae
Group V. (-) Sense single-stranded RNA viruses
Require viral RNA-dependent RNA transcriptase.
Segmented, enveloped:
Orthomyxoviridae
Nonsegmented, enveloped:
Filoviridae
Rhabdoviridae
Paramyxoviridae
Segmented (+/-) strand enveloped:
Arenaviridae
Bunyaviridae
Hantavirus
Group VI. RNA Reverse Transcribing Viruses (Retroviruses)
Require viral reverse transcriptase to generate DNA copy for integration into host chromosome.
Package transcriptase before exiting host cell.
Retroviridae
Lentivirus
Human Immunodeficiency Virus
Group VII. DNA Reverse Transcribing Viruses (Pararetroviruses)
DNA is transcribed to RNA intermediate; reverse-transcribed to DNA.
Infects plant cells, which have cytoplasmic reverse transcriptase; or package a viral reverse transcriptase.
Non-enveloped plant viruses:
Caulimoviridae
Badnavirus
Caulimovirus
Enveloped animal viruses:
Hepadnaviridae
Orthohepadnavirus
Hepatitis B virus
Trait Transfer: Bacteria Genes.
INDEX
http://www.
LINK 2: http:// (00 DOWN)
LINK 3: http://www. (00 DOWN)
LINK 4: http:// (00 DOWN)
LINK 5: https:// (00 DOWN)
LINK 6: http://www. (00 DOWN)
B , 2011
From
Micrki, the
Trait Transfer: Reptile Genes.
INDEX
https://en.wikivet.net/Lizard_Digestion
LINK 2: http://www.viovet.co.uk/Reptile_Digestion/c969/ (WV DOWN)
LINK 3: https://en.wikipedia.org/wiki/Reptile (WK DOWN)
LINK 4: http://www.ehow.com/about_6391203_do-reptiles-digest_.html (EH DOWN)
LINK 5: http://www.newworldencyclopedia.org/entry/Reptile (NW DOWN)
LINK 6: http://www.britannica.com/animal/reptile/Digestive-and-urogenital-systems (BT DOWN)
Reptile Digestion, 2015
From
VioVet, http://www.viovet.co.uk/Reptile_Digestion/c969/
VioVet Ltd, 53 Bilton Way, Luton, Beds, LU1 1UU
... a(n) FOS prebiotic ... enhances the gut bacteria ...
Allium sativum (garlic), thymus vulgaris (common thyme), picrasma excelsa (quassia), foeniculum vulgare (fennel), mentha piperita (peppermint), galium Aparine (cleavers), urtica dioica (nettle), ulmus fulva (slippery elm) ... are used to provide relief to a stressed stomach ....
Reptile, July 07, 2015
From
Wikipedia, https://en.wikipedia.org/wiki/Reptile
... The earliest known reptiles originated around 315 million years ago..
ecologically adapted to the drier conditions ... They acquired new feeding strategies including herbivory and carnivory, previously only having been insectivores and piscivores. ... Due to a less stable core temperature than birds and mammals, reptilian biochemistry requires enzymes capable of maintaining efficiency over a greater range of temperatures than in the case for warm-blooded animals. ...
The benefit of a low resting metabolism is that it requires far less fuel to sustain bodily functions.
By using temperature variations in their surroundings, or by remaining cold when they do not need to move, reptiles can save considerable amounts of energy compared to endothermic animals of the same size. A crocodile needs from a tenth to a fifth of the food necessary for a lion of the same weight and can live half a year without eating. ...
Excretion is performed mainly by two small kidneys.
In diapsids, uric acid is the main nitrogenous waste product; turtles, like mammals, excrete mainly urea.
Unlike the kidneys of mammals and birds, reptile kidneys are unable to produce liquid urine more concentrated than their body fluid. This is because they lack a specialized structure called a loop of Henle, which is present in the nephrons of birds and mammals. Because of this, many reptiles use the colon to aid in the reabsorption of water. ...
Most reptiles are insectivorous or carnivorous and have rather simple and comparatively short digestive tracts, meat being fairly simple to break down and digest. Digestion is slower than in mammals, reflecting their lower resting metabolism and their inability to divide and masticate their food. Their poikilotherm metabolism has very low energy requirements, allowing large reptiles like crocodiles and the large constrictors to live from a single large meal for months, digesting it slowly. ...
Larger lizards, like the monitors, are known to exhibit complex behavior, including cooperation.
Crocodiles have relatively larger brains and show a fairly complex social structure.
The Komodo dragon is even known to engage in play, as are turtles, which are also considered to be social creatures and sometimes switch between monogamy and promiscuity in their sexual behavior. ....
About do-reptiles-digest, 2011
From
Ehow, http://www.ehow.com/about_6391203_do-reptiles-digest_.html.
Reptile, 2008
From
New World Encyclopedia: Reptile, http://www.newworldencyclopedia.org/entry/Reptile
Most reptiles have closed circulation via a three-chamber heart comprising two atria and one variably-partitioned ventricle. ... the blood flow can be altered to shunt either deoxygenated blood to the body or oxygenated blood to the lungs, which gives the animal greater control over its blood flow, allowing more effective thermoregulation and longer diving times for aquatic species.
... crocodilians have an incredibly complicated four-chamber heart that is capable of becoming a functionally three-chamber heart during dives (Mazzotti 1989). Also, it has been discovered that some snake and lizard species (for example, monitor lizards and pythons) have three-chamber hearts that become functional four-chamber hearts during contraction. This is made possible by a muscular ridge that subdivides the ventricle during ventricular diastole and completely divides it during ventricular systole. Because of this ridge, some of these squamates are capable of producing ventricular pressure differentials that are equivalent to those seen in mammalian and avian hearts.
... Land-dwelling reptiles, such as snakes and lizards, excrete nitrogenous wastes in pasty or dry form as crystals of uric acid. ... Saliva begins to digest food before it reaches the stomach, which is basically an enlargement at the end of the esophagus where digestion can slowly proceed. ...
The crocodile stomach is divided into two chambers, the first one is described as being powerful and muscular .... The other stomach has the most acidic digestive system of any animal, and it can digest mostly everything from their prey; bones, feathers, and horns. ..
... salmonella, a bacterial disease, is sometimes picked up from a reptile's skin ...
Reptiles: Digestive and urogenital systems, July 14, 2015
From
Britannica, Digestive-and-urogenital-systems.
Written by: George R. Zug
The principal functions of the kidney are the removal of nitrogenous wastes resulting from the oxidation of proteins and the regulation of water loss. Vertebrates eliminate three kinds of nitrogenous wastes: ammonia, urea, and uric acid. Ammonia and urea are highly soluble in water, but uric acid is not. Ammonia is highly poisonous, urea is slightly poisonous, and uric acid is not poisonous at all. ...
Among reptiles the form taken by the nitrogenous wastes is closely related to the habits and habitat of the animal. Aquatic reptiles tend to excrete a large proportion of these wastes as ammonia in aqueous solution. This method uses large amounts of water and is no problem for a freshwater resident, such as an alligator, which eliminates between 40 and 75 percent of its nitrogenous wastes as ammonia. Terrestrial reptiles, such as most snakes and lizards, must conserve body water, and they convert their nitrogenous wastes to insoluble, harmless uric acid, which forms a more or less solid mass in the cloaca. ...
Trait Transfer: Virus Genes - Ringspot.
INDEX
https://en.wikipedia.org/wiki/Papaya_ringspot_virus
LINK 2: http://www.gmo-compass.org/eng/database/plants/59.papaya.html
LINK 3: http://www.annualreviews.org/
doi/abs/10.1146/annurev.phyto.36.1.415?journalCode=phyto&
LINK 4: http://www.sourcewatch.org/index.php/
Papaya_Ringspot_Virus_Resistant_%28PRSVR%29_Papaya
PRSV-P
Symptoms are typical of viral diseases.
Papaya exhibits yellowing, leaf distortion, and severe mosaic.
Oily or water-soaked spots and streaks appear on the trunk and petioles.
The fruit will exhibit bumps and the classic "ringspot". A severe isolate of PRSV has also been shown to cause tissue necrosis. Cucurbit symptoms tend to be similar to papaya symptoms including blisters, mosaic, yellowing, and leaf distortions.
This virus produces two types of inclusion bodies visible under a light microscope with proper staining of epidemal strips. One inclusion is the typical cylidrical inclusion (CI) which is considered diagnostic for the potyvirus group, and the other is called the amorphous inclusion (AI). The presence of both inclusions can be diagnostic for this virus.
Autopsy: Internal Exam - Impacted Waste
http://www.youtube.com/watch?v=bj3d7p2Fu6M
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