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Rhizobium Meliloti
''Ensifer meliloti'' (formerly ''Rhizobium meliloti'' and ''Sinorhizobium meliloti'') are an aerobic, Gram-negative, and diazotrophic species of bacteria. ''S. meliloti'' are motile and possess a cluster of peritrichous flagella. ''S. meliloti'' fix atmospheric nitrogen into ammonia for their legume hosts, such as alfalfa. ''S. meliloti'' forms a symbiotic relationship with legumes from the genera ''Medicago'', ''Melilotus'' and ''Trigonella'', including the model legume ''Medicago truncatula''. This symbiosis promotes the development of a plant organ, termed a root nodule. Because soil often contains a limited amount of nitrogen for plant use, the symbiotic relationship between ''S. meliloti'' and their legume hosts has agricultural applications. These techniques reduce the need for inorganic nitrogenous fertilizers. Symbiosis Symbiosis between ''S. meliloti'' and its legume hosts begins when the plant secretes an array of betaines and flavonoids into the rhizosphere: 4,4′-di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agar Plate
An agar plate is a Petri dish that contains a growth medium solidified with agar, used to Microbiological culture, culture microorganisms. Sometimes selective compounds are added to influence growth, such as antibiotics. Individual microorganisms placed on the plate will grow into individual colony (biology), colonies, each a cloning, clone genetically identical to the individual ancestor organism (except for the low, unavoidable rate of mutation). Thus, the plate can be used either to estimate the concentration of organisms in a Microbiological culture, liquid culture or a suitable dilution of that culture using a colony counter, or to generate genetically pure cultures from a mixed culture of genetically different organisms. Several methods are available to plate out cells. One technique is known as "Streaking (microbiology), streaking". In this technique, a drop of the culture on the end of a thin, sterilization (microbiology), sterile loop of wire, sometimes known as an inocu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Betaine
A betaine () in chemistry is any neutral chemical compound with a positively charged cationic functional group that bears no hydrogen atom, such as a Quaternary ammonium cation, quaternary ammonium or phosphonium cation (generally: Onium compounds, onium ions), and with a negatively charged functional group, such as a carboxylate group that may not be adjacent to the cationic site. Historically, the term was reserved for trimethylglycine (TMG), which is involved in methylation reactions and detoxification of homocysteine. This is a modified amino acid consisting of glycine with three methyl groups serving as methyl donor for various metabolic pathways. Pronunciation The pronunciation of the compound reflects its origin and first isolation from sugar ''beets'' (''Beta vulgaris'' subsp. ''vulgaris''), and does not derive from the Greek letter beta (β). It is commonly pronounced ''beta-INE'' or ''BEE-tayn''. Glycine betaine The original betaine, ''N'',''N'',''N''-trimethyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhizobia
Rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside the root nodules of legumes (Fabaceae). To express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen. In general, they are gram negative, motile, non- sporulating rods. Rhizobia are a "group of soil bacteria that infect the roots of legumes to form root nodules". Rhizobia are found in the soil and, after infection, produce nodules in the legume where they fix nitrogen gas (N2) from the atmosphere, turning it into a more readily useful form of nitrogen. From here, the nitrogen is exported from the nodules and used for growth in the legume. Once the legume dies, the nodule breaks down and releases the rhizobia back into the soil, where they can live individually or reinfect a new legume host. History The first known species of rhizobia, '' Rhizobium leguminosarum'', was identified in 1889, and all further species were initially placed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nod Factor
Nod factors (nodulation factors or NF), are signaling molecules produced by soil bacteria known as rhizobia in response to flavonoid exudation from plants under nitrogen limited conditions. Nod factors initiate the establishment of a symbiotic relationship between legumes and rhizobia by inducing nodulation. Nod factors produce the differentiation of plant tissue in root hairs into nodules where the bacteria reside and are able to fix nitrogen from the atmosphere for the plant in exchange for photosynthates and the appropriate environment for nitrogen fixation. One of the most important features provided by the plant in this symbiosis is the production of leghemoglobin, which maintains the oxygen concentration low and prevents the inhibition of nitrogenase activity. Chemical Structure Nod factors structurally are lipochitooligosaccharides (LCOs) that consist of an ''N''-acetyl-D-glucosamine chain linked through β-1,4 linkage with a fatty acid of variable identity attached to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigonelline
Trigonelline is an alkaloid with chemical formula . It is a zwitterion formed by the methylation of the nitrogen atom of niacin (vitamin B3). Trigonelline is a product of niacin metabolism that is excreted in the urine of mammals. Trigonelline occurs in many plants. It has been isolated from the Japanese radish (''Raphanus sativus'' cv. Sakurajima Daikon), fenugreek seeds (''Trigonella foenum-graecum'', hence the name), garden peas, hemp seed, oats, potatoes, ''Stachys'' species, dahlia, ''Strophanthus'' species, and '' Dichapetalum cymosum''. Trigonelline is also found in coffee. Higher levels of trigonelline are found in arabica coffee. Holtz, Kutscher, and Theilmann have recorded its presence in a number of animals. Chemistry Trigonelline crystallizes as a monohydrate from alcohol in hygroscopic prisms (m.p. 130 °C or 218 °C 'dry, dec.''. It is readily soluble in water or warm alcohol, less so in cold alcohol, and slightly so in chloroform or ether. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medicarpin
Medicarpin is a pterocarpan, a derivative of isoflavonoids. Natural occurrences Medicarpin is found in ''Medicago truncatula'' and ''Swartzia madagascariensis''. It can also be found in ''Maackia amurensis'' cell cultures. The root nodule formation by ''Sinorhizobium meliloti'' is apparently dependent on the flavonoids pathway. Metabolism Pterocarpin synthase has 3 substrates : medicarpin, nicotinamide adenine dinucleotide phosphate, NADP+ and water, H2O, and 3 products : vestitone, nicotinamide adenine dinucleotide phosphate, NADPH and hydrogen ion, H+. References Pterocarpans Methoxy compounds {{aromatic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
