Raoultella planticola | |
---|---|
Scientific classification | |
Domain: | |
Phylum: | |
Class: | |
Order: | |
Family: | |
Genus: | |
Species: | R. planticola |
Binomial name | |
Raoultella planticola Bagley et al. 1982 [1] | |
Synonyms | |
Klebsiella planticola, [2] [3] [4] [5] [6] [7] [8] Klebsiella trevisanii [9] Contents |
Raoultella planticola is a Gram-negative [10] bacterium of the genus Raoultella . [5] [11] [12] [13] [14] [15] [16] R. planticola is quite similar in appearance to Klebsiella pneumoniae and must be identified based on growth habits or DNA analysis. A number of strains have been identified. [17] [18]
Infections are rare, and mostly seen in immunocompromised patients. [19] [20] [21] R. planticola has been determined to have complicated at least one case of severe pancreatitis. [22]
A strain of Raoultella planticola, Cd-1 has been found which grows anaerobically at high aqueous cadmium concentrations and precipitates insoluble cadmium sulfide. This strain has been isolated from reducing salt marsh sediments and may be useful in bioremediation of cadmium from exposed soils. [23]
Raoultella planticola was formerly classified as part of the genus Klebsiella . It was reclassified along with several other Klebsiella species in 2001. [24]
In the late 1980s R. planticola was genetically modified by inserting a plasmid from Zymomonas mobilis . This plasmid codes for the enzyme pyruvate decarboxylase which, along with alcohol dehydrogenase already present in the bacteria allow it to produce ethanol. The bacteria already does produce ethanol when metabolizing hexoses and pentoses, but very inefficiently. R. planticola was chosen to receive this gene as it already had metabolic pathways to breakdown pentose sugars such as xylose, which is a main component of agricultural and forest residues. [25] [26] The results showed that the genetically modified strain could produce ethanol but were killed at concentrations of ethanol greater than 5%. The modified strain also produced more ethanol at lower pH (5.4) and ethanol production decreased as pH increased. [25]
In the early 1990s, a biotech company set out to solve a problem: how to destroy crop residue safely. Some crops' residues harbor plant pathogens. Burning is occasionally used to destroy the residue and pathogens, but this is a fire hazard and can be dangerous for the environment. This company realized that, because R. planticola is an aggressive and abundant soil bacterium, it could be genetically modified to destroy crop residue and also create ethanol.
Testing of this process was originally limited to sterile soil. Ph.D. research conducted at Oregon State University, supervised by Elaine Ingham, obtained a sample of the genetically modified organism for assessing ecological effects through the German Institut für Biotechnologie and, testing it in non-sterile (ordinary) soil, found that the modified bacteria caused small amounts of alcohol in the soil. [27] [28] [29] While this level is several hundred times lower than required to affect planth growth, this fact combined with the fact that R. planticola is already found growing in the root systems of all kinds of plants everywhere, sparked a doomsday myth. [30] [28]
Dr Ingham claimed to a New Zealand Commission that "the likely effect of allowing the field trial [with the genetically modified bacteria in question] would have been to destroy terrestrial plants". [30] [28] [31] Ingham's suggestion of a possibility of "worldwide plant death" attracted attention from the scientific community. However, they were unable to find any evidence that these claims had been submitted to scientific publication in a peer-reviewed journal, and no evidence was found to indicate the U.S. EPA or U.S. Dept. of Agriculture had reviewed or approved any trials for SDF20. [31] [32] Additionally, the SDF20 was found to have produced 20 micrograms per milliliter of alcohol in the soil which is several hundred times lower than that required to affect plant growth. [33] [32]
Elaine Ingham has issued a public apology for submitting false claims about ecological impact of GMOs. [34]
The Green Party of New Zealand has issued a public apology for misleading statements and acknowledging that a cited research was never published. [35]
In the episode "The Pyramid at the End of the World" of the BBC television show Doctor Who, the Doctor stops a genetically modified strain of R. planticola from causing a worldwide plant and animal die-off similar to the scenario that some scientists have speculated about.
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, 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.
Gram-negative bacteria are bacteria that unlike gram-positive bacteria do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is their cell envelope, which consists of a thin peptidoglycan cell wall sandwiched between an inner (cytoplasmic) membrane and an outer membrane. These bacteria are found in all environments that support life on Earth.
Klebsiella pneumoniae is a Gram-negative, non-motile, encapsulated, lactose-fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar.
Lactococcus lactis is a gram-positive bacterium used extensively in the production of buttermilk and cheese, but has also become famous as the first genetically modified organism to be used alive for the treatment of human disease. L. lactis cells are cocci that group in pairs and short chains, and, depending on growth conditions, appear ovoid with a typical length of 0.5 - 1.5 μm. L. lactis does not produce spores (nonsporulating) and are not motile (nonmotile). They have a homofermentative metabolism, meaning they produce lactic acid from sugars. They've also been reported to produce exclusive L-(+)-lactic acid. However, reported D-(−)-lactic acid can be produced when cultured at low pH. The capability to produce lactic acid is one of the reasons why L. lactis is one of the most important microorganisms in the dairy industry. Based on its history in food fermentation, L. lactis has generally recognized as safe (GRAS) status, with few case reports of it being an opportunistic pathogen.
Acidobacteriota is a phylum of Gram-negative bacteria. Its members are physiologically diverse and ubiquitous, especially in soils, but are under-represented in culture.
Agrobacterium tumefaciens is the causal agent of crown gall disease in over 140 species of eudicots. It is a rod-shaped, Gram-negative soil bacterium. Symptoms are caused by the insertion of a small segment of DNA, from a plasmid into the plant cell, which is incorporated at a semi-random location into the plant genome. Plant genomes can be engineered by use of Agrobacterium for the delivery of sequences hosted in T-DNA binary vectors.
Agrobacterium is a genus of Gram-negative bacteria established by H. J. Conn that uses horizontal gene transfer to cause tumors in plants. Agrobacterium tumefaciens is the most commonly studied species in this genus. Agrobacterium is well known for its ability to transfer DNA between itself and plants, and for this reason it has become an important tool for genetic engineering.
Bacillus subtilis, known also as the hay bacillus or grass bacillus, is a gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants, humans and marine sponges. As a member of the genus Bacillus, B. subtilis is rod-shaped, and can form a tough, protective endospore, allowing it to tolerate extreme environmental conditions. B. subtilis has historically been classified as an obligate aerobe, though evidence exists that it is a facultative anaerobe. B. subtilis is considered the best studied Gram-positive bacterium and a model organism to study bacterial chromosome replication and cell differentiation. It is one of the bacterial champions in secreted enzyme production and used on an industrial scale by biotechnology companies.
Klebsiella is a genus of Gram-negative, oxidase-negative, rod-shaped bacteria with a prominent polysaccharide-based capsule.
Multilocus sequence typing (MLST) is a technique in molecular biology for the typing of multiple loci, using DNA sequences of internal fragments of multiple housekeeping genes to characterize isolates of microbial species.
Clostridium acetobutylicum, ATCC 824, is a commercially valuable bacterium sometimes called the "Weizmann Organism", after Jewish Russian-born biochemist Chaim Weizmann. A senior lecturer at the University of Manchester, England, he used them in 1916 as a bio-chemical tool to produce at the same time, jointly, acetone, ethanol, and n-butanol from starch. The method has been described since as the ABE process,, yielding 3 parts of acetone, 6 of n-butanol, and 1 of ethanol. Acetone was used in the important wartime task of casting cordite. The alcohols were used to produce vehicle fuels and synthetic rubber.
Burkholderia pseudomallei is a Gram-negative, bipolar, aerobic, motile rod-shaped bacterium. It is a soil-dwelling bacterium endemic in tropical and subtropical regions worldwide, particularly in Thailand and northern Australia. It was reported in 2008 that there had been an expansion of the affected regions due to significant natural disasters, and it could be found in Southern China, Hong Kong, and countries in the Americas. B. pseudomallei, amongst other pathogens, has been found in monkeys imported into the United States from Asia for laboratory use, posing a risk that the pathogen could be introduced into the country.
In biochemistry, mixed acid fermentation is the metabolic process by which a six-carbon sugar is converted into a complex and variable mixture of acids. It is an anaerobic (non-oxygen-requiring) fermentation reaction that is common in bacteria. It is characteristic for members of the Enterobacteriaceae, a large family of Gram-negative bacteria that includes E. coli.
Klebsiella oxytoca is a Gram-negative, rod-shaped bacterium that is closely related to K. pneumoniae, from which it is distinguished by being indole-positive; it also has slightly different growth characteristics in that it is able to grow on melezitose, but not 3-hydroxybutyrate. It was first described in 1886 when it was isolated from sour milk and named Bacillus oxytocus perniciosus.
The Crabtree effect, named after the English biochemist Herbert Grace Crabtree, describes the phenomenon whereby the yeast, Saccharomyces cerevisiae, produces ethanol (alcohol) in aerobic conditions at high external glucose concentrations rather than producing biomass via the tricarboxylic acid (TCA) cycle, the usual process occurring aerobically in most yeasts e.g. Kluyveromyces spp. This phenomenon is observed in most species of the Saccharomyces, Schizosaccharomyces, Debaryomyces, Brettanomyces, Torulopsis, Nematospora, and Nadsonia genera. Increasing concentrations of glucose accelerates glycolysis which results in the production of appreciable amounts of ATP through substrate-level phosphorylation. This reduces the need of oxidative phosphorylation done by the TCA cycle via the electron transport chain and therefore decreases oxygen consumption. The phenomenon is believed to have evolved as a competition mechanism around the time when the first fruits on Earth fell from the trees. The Crabtree effect works by repressing respiration by the fermentation pathway, dependent on the substrate.
Klebsiella aerogenes, previously known as Enterobacter aerogenes, is a Gram-negative, oxidase-negative, catalase-positive, citrate-positive, indole-negative, rod-shaped bacterium. Capable of motility via peritrichous flagella, the bacterium is approximately 1–3 microns in length.
D-Xylose is a five-carbon aldose that can be catabolized or metabolized into useful products by a variety of organisms.
Episoriculus is a genus of shrew in the red-toothed shrew subfamily. Its common is brown-toothed shrew. It has been described as a subgenus to Soriculus in the past. The genus occurs at a number of locations in Asia, including Nepal and China.
Raoultella terrigena is a Gram-negative bacterial species of the genus Raoultella, previously classified in the genus Klebsiella. It has primarily been isolated from soil and water samples, but rarely from humans. Studies have estimated fewer than 1% of healthy people harbor this species. This species has rarely been shown to cause disease in humans despite expressing many of the virulence factors expressed by other Klebsiella species such as Klebsiella pneumoniae.
Caldicellulosiruptor bescii is a species of thermophilic, anaerobic cellulolytic bacteria. It was isolated from a geothermally heated freshwater pool in the Valley of Geysers on the Kamchatka Peninsula in Russia in 1990. The species was originally named Anaerocellum thermophilum, but reclassified in 2010, based on genomic data.