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Extracellular Polymeric Substance
Extracellular polymeric substances (EPSs) are natural polymers of high molecular weight secreted by microorganisms into their environment. EPSs establish the functional and structural integrity of biofilms, and are considered the fundamental component that determines the physicochemical properties of a biofilm. EPS in the matrix of biofilms provides compositional support and protection of microbial communities from the harsh environments. Components of EPS can be of different classes of polysaccharides, lipids, nucleic acids, proteins, Lipopolysaccharides, and minerals. Components EPSs are mostly composed of polysaccharides (exopolysaccharides) and proteins, but include other macromolecules such as DNA, lipids and humic substances. EPSs are the construction material of bacterial settlements and either remain attached to the cell's outer surface, or are secreted into its growth medium. These compounds are important in biofilm formation and cells' attachment to surfaces. EP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biofilm Formation
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs). The cells within the biofilm produce the EPS components, which are typically a polymeric conglomeration of extracellular polysaccharides, proteins, lipids and DNA. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes". Biofilms may form on living or non-living surfaces and can be prevalent in natural, industrial, and hospital settings. They may constitute a microbiome or be a portion of it. The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single cells that may float or swim in a liquid medium. Biofilms can form on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyruvate
Pyruvic acid (CH3COCOOH) is the simplest of the alpha-keto acids, with a carboxylic acid and a ketone functional group. Pyruvate, the conjugate base, CH3COCOO−, is an intermediate in several metabolic pathways throughout the cell. Pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through a reaction with acetyl-CoA. It can also be used to construct the amino acid alanine and can be converted into ethanol or lactic acid via fermentation. Pyruvic acid supplies energy to cells through the citric acid cycle (also known as the Krebs cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactate when oxygen is lacking. Chemistry In 1834, Théophile-Jules Pelouze distilled tartaric acid and isolated glutaric acid and another unknown organic acid. Jöns Jacob Berzelius characterized this other acid the following year and named pyruvic acid bec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Desiccation Tolerance
Desiccation tolerance refers to the ability of an organism to withstand or endure extreme dryness, or drought-like conditions. Plants and animals living in arid or periodically arid environments such as temporary streams or ponds may face the challenge of desiccation, therefore physiological or behavioral adaptations to withstand these periods are necessary to ensure survival. In particular, insects occupy a wide range of ecologically diverse niches and, so, exhibit a variety of strategies to avoid desiccation. In general, desiccation resistance in insects is measured by the change in mass during dry conditions. The overall mass difference between measurements before and after aridity exposure is attributed to body water loss, as respiratory water loss is generally considered negligible. Desiccation and plants Desiccation tolerant plants include '' Craterostigma plantagineum'', ''Lindernia brevidens'' and ''Ramonda serbica''. Desiccation sensitive plants include members of ''Ara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogenic Bacteria
Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract. The body is continually exposed to many species of bacteria, including beneficial commensals, which grow on the skin and mucous membranes, and saprophytes, which grow mainly in the soil and in decaying matter. The blood and tissue fluids contain nutrients sufficient to sustain the growth of many bacteria. The body has defence mechanisms that enable it to resist microbial invasion of its tissues and give it a natural immunity or innate resistance against many microorganisms. Pathogenic bacteria are specially adapted and endowed with mechanisms for overcoming the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucan
A glucan is a polysaccharide derived from D-glucose, linked by glycosidic bonds. Glucans are noted in two forms: alpha glucans and beta glucans. Many beta-glucans are medically important. They represent a drug target for antifungal medications of the echinocandin class. Types The following are glucans (The α- and β- and numbers clarify the type of O- glycosidic bond and the specific carbons involved): Alpha * dextran, α-1,6-glucan with α-1,3-branches * floridean starch, α-1,4- and α-1,6-glucan * glycogen, α-1,4- and α-1,6-glucan * pullulan, α-1,4- and α-1,6-glucan * starch, a mixture of amylose and amylopectin, both α-1,4- and α-1,6-glucans Beta * cellulose, β-1,4-glucan * chrysolaminarin, β-1,3-glucan * curdlan, β-1,3-glucan * laminarin, β-1,3- and β-1,6-glucan * lentinan, a strictly purified β-1,6:β-1,3-glucan from '' Lentinus edodes'' * lichenin, β-1,3- and β-1,4-glucan * oat beta-glucan, β-1,3- and β-1,4-glucan * pleuran, β-1,3- a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leishmania Tropica
''Leishmania tropica'' is a flagellate parasite and the cause of anthroponotic cutaneous leishmaniasis in humans. This parasite is restricted to Afro-Eurasia and is a common cause of infection in Afghanistan, Iran, Syria, Yemen, Algeria, Morocco, and northern India. History The first description of ''Leishmania tropica'' was done in 1903 by James Homer Wright, an American pathologist. In 1914, it was suggested that ''L. tropica'' should be divided into two subspecies, namely ''L. tropica minor'' and ''L. tropica major'', based on the size of the parasites found in skin lesions. Later, these two subspecies turned out to be epidemiologically different and were correlated to different types of lesions. ''L. tropica minor'' causes dry nodular lesions in urban environments, while ''L. tropica major'' causes wet ulcerating lesions in rural regions. Bray et al. therefore proposed in 1973 that the subspecies should be considered as two separate species, ''L. tropica major'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trypanosomatida
Trypanosomatida is a group of kinetoplastid excavates distinguished by having only a single flagellum. The name is derived from the Greek language, Greek ''trypano'' (borer) and ''soma'' (body) because of the corkscrew-like motion of some trypanosomatid species. All members are exclusively parasite, parasitic, found primarily in insects. A few genera have life-cycles involving a secondary host, which may be a vertebrate, invertebrate or plant. These include several species that cause major diseases in humans. Some trypanosomatida are intracellular parasites, with the important exception of Trypanosoma brucei. Medical importance The three major human diseases caused by trypanosomatids are; African trypanosomiasis (African trypanosomiasis, sleeping sickness, caused by ''Trypanosoma brucei'' and transmitted by Tsetse fly, tsetse flies), South American trypanosomiasis (Chagas disease, caused by ''Trypanosoma cruzi, T. cruzi'' and transmitted by Triatominae, triatomine bugs), and le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiparasitic
Antiparasitics are a class of medications which are indicated for the treatment of parasitic diseases, such as those caused by helminths, amoeba, ectoparasites, parasitic fungi, and protozoa, among others. Antiparasitics target the parasitic agents of the infections by destroying them or inhibiting their growth; they are usually effective against a limited number of parasites within a particular class. Antiparasitics are one of the antimicrobial drugs which include antibiotics that target bacteria, and antifungals that target fungi. They may be administered orally, intravenously or topically. Broad-Spectrum antiparasitics, analogous to broad-spectrum antibiotics for bacteria, are antiparasitic drugs with efficacy in treating a wide range of parasitic infections caused by parasites from different classes. Types Broad-spectrum * Nitazoxanide Antiprotozoals * Melarsoprol (for treatment of sleeping sickness caused by ''Trypanosoma brucei'') * Eflornithine (for sleeping si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer Cell
Cancer cells are cells that divide continually, forming solid tumors or flooding the blood with abnormal cells. Cell division is a normal process used by the body for growth and repair. A parent cell divides to form two daughter cells, and these daughter cells are used to build new tissue or to replace cells that have died because of aging or damage. Healthy cells stop dividing when there is no longer a need for more daughter cells, but cancer cells continue to produce copies. They are also able to spread from one part of the body to another in a process known as metastasis. Classification There are different categories of cancer cell, defined according to the cell type from which they originate. * Carcinoma, the majority of cancer cells are epithelial in origin, beginning in a tissue that lines the inner or outer surfaces of the body. * Leukaemia, originate in the tissues responsible for producing new blood cells, most commonly in the bone marrow. * Lymphoma and myeloma, deriv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breast Cancer
Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a red or scaly patch of skin. In those with distant spread of the disease, there may be bone pain, swollen lymph nodes, shortness of breath, or yellow skin. Risk factors for developing breast cancer include obesity, a lack of physical exercise, alcoholism, hormone replacement therapy during menopause, ionizing radiation, an early age at first menstruation, having children late in life or not at all, older age, having a prior history of breast cancer, and a family history of breast cancer. About 5–10% of cases are the result of a genetic predisposition inherited from a person's parents, including BRCA1 and BRCA2 among others. Breast cancer most commonly develops in cells from the lining of milk ducts and the lobules that su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhabdomyosarcoma
Rhabdomyosarcoma (RMS) is a highly aggressive form of cancer that develops from mesenchymal cells that have failed to fully differentiate into myocytes of skeletal muscle. Cells of the tumor are identified as rhabdomyoblasts. There are four subtypes – embryonal rhabdomyosarcoma, alveolar rhabdomyosarcoma, pleomorphic rhabdomyosarcoma, and spindle cell/sclerosing rhabdomyosarcoma. Embryonal, and alveolar are the main groups, and these types are the most common soft tissue sarcomas of childhood and adolescence. The pleomorphic type is usually found in adults. It is generally considered to be a disease of childhood, as the vast majority of cases occur in those below the age of 18. It is commonly described as one of the small-blue-round-cell tumors of childhood due to its appearance on an H&E stain. Despite being relatively rare, it accounts for approximately 40% of all recorded soft tissue sarcomas. RMS can occur in any soft tissue site in the body, but is primarily found in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantoea Agglomerans
''Pantoea agglomerans'' is a Gram-negative bacterium that belongs to the family Erwiniaceae. It was formerly called ''Enterobacter agglomerans'', or ''Erwinia herbicola'' and is a ubiquitous bacterium commonly isolated from plant surfaces, seeds, fruit, and animal or human feces and can be found throughout a honeybee's environment. Levan produced by ''Pantoea agglomerans'' ZMR7 was reported to decrease the viability of rhabdomyosarcoma (RD) and breast cancer (MDA) cells compared with untreated cancer cells. In addition, it has high antiparasitic activity against the promastigote of ''Leishmania tropica''. Plant Disease Biocontrol ''Pantoea agglomerans'' can serve as a biocontrol organism for the management of plant diseases. It has been used to control fire blight, a plant disease caused by bacterium ''Erwinia amylovora,'' that is a common problem in pear and apple crops. After coming in contact with ''Erwinia amylovora'', ''Pantoea agglomerans'' produces antibiotic compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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