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M. Leprae
''Mycobacterium leprae'' (also known as the leprosy bacillus or Hansen's bacillus) is one of the two species of bacteria that cause Hansen's disease (leprosy), a chronic but curable infectious disease that damages the peripheral nerves and targets the skin, eyes, nose, and muscles. It is an acid-fast, Gram-positive, rod shaped bacterium and an obligate intracellular parasite, which means, unlike its relative ''Mycobacterium tuberculosis'', it cannot be grown in cell-free laboratory media. This is likely due to gene deletion and decay that the genome of the species has experienced via reductive evolution, which has caused the bacterium to depend heavily on its host for nutrients and metabolic intermediates. It has a narrow host range and apart from humans, the only other natural hosts are nine-banded armadillo and red squirrels. The bacteria infect mainly macrophages and Schwann cells, and are typically found congregated as a palisade. ''Mycobacterium leprae'' was sensitive t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerhard Armauer Hansen
Gerhard Henrik Armauer Hansen (; 29 July 1841 – 12 February 1912) was a Norwegians, Norwegian physician, remembered for his identification of the Bacteria, bacterium ''Mycobacterium leprae'' in 1873 as the causative agent of leprosy. His distinguished work was recognized at the International Leprosy Congress held at Bergen in 1909. Life Hansen was born in Bergen, Norway, and attended the Bergen Cathedral School. He worked at Rikshospitalet in Oslo, Christiania (now Oslo) and as a doctor in Lofoten. In 1868 Hansen returned to Bergen to study leprosy while working at Lungegård Hospital () with Daniel Cornelius Danielssen, a noted expert. Leprosy was regarded as largely hereditary or otherwise miasma theory of disease, miasmic in origin. Hansen concluded on the basis of Epidemiology, epidemiological studies that leprosy was a specific disease with a specific cause. In 1870–71 Hansen travelled to Bonn and Vienna to gain the training necessary for him to prove his hypothesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibiotic Resistance
Antimicrobial resistance (AMR or AR) occurs when microbes evolve mechanisms that protect them from antimicrobials, which are drugs used to treat infections. This resistance affects all classes of microbes, including bacteria (antibiotic resistance), viruses (antiviral resistance), parasites (antiparasitic resistance), and fungi (antifungal resistance). Together, these adaptations fall under the AMR umbrella, posing significant challenges to healthcare worldwide. Misuse and improper management of antimicrobials are primary drivers of this resistance, though it can also occur naturally through genetic mutations and the spread of resistant genes. Antibiotic resistance, a significant AMR subset, enables bacteria to survive antibiotic treatment, complicating infection management and treatment options. Resistance arises through spontaneous mutation, horizontal gene transfer, and increased selective pressure from antibiotic overuse, both in medicine and agriculture, which accelerat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycolic Acid
Mycolic acids are long fatty acids found in the cell walls of Mycobacteriales taxon, a group of bacteria that includes ''Mycobacterium tuberculosis'', the causative agent of the disease tuberculosis. They form the major component of the cell wall of many Mycobacteriales species. Despite their name, mycolic acids have no biological link to fungi; the name arises from the filamentous appearance their presence gives Mycobacteriales under high magnification. The presence of mycolic acids in the cell wall also gives Mycobacteriales a distinct gross morphological trait known as " cording". Mycolic acids were first isolated by Stodola ''et al.'' in 1938 from an extract of ''M. tuberculosis''. Mycolic acids are composed of a longer beta-hydroxy chain with a shorter alpha-alkyl side chain. Each molecule contains between 60 and 90 carbon atoms. The exact number of carbons varies by species and can be used as an identification aid. Most mycolic acids also contain various functional gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacillus
''Bacillus'', from Latin "bacillus", meaning "little staff, wand", is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum ''Bacillota'', with 266 named species. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural ''Bacilli'' is the name of the class of bacteria to which this genus belongs. ''Bacillus'' species can be either obligate aerobes which are dependent on oxygen, or facultative anaerobes which can survive in the absence of oxygen. Cultured ''Bacillus'' species test positive for the enzyme catalase if oxygen has been used or is present. ''Bacillus'' can reduce themselves to oval endospores and can remain in this dormant state for years. The endospore of one species from Morocco is reported to have survived being heated to 420 °C. Endospore formation is usually triggered by a lack of nutrients: the bacterium divides within its cell wall, and one side then engulfs the other. They are not true spores (i.e. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerobic Organism
An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment. The ability to exhibit aerobic respiration may yield benefits to the aerobic organism, as aerobic respiration yields more energy than anaerobic respiration. Energy production of the cell involves the synthesis of ATP by an enzyme called ATP synthase. In aerobic respiration, ATP synthase is coupled with an electron transport chain in which oxygen acts as a terminal electron acceptor. In July 2020, marine biologists reported that aerobic microorganisms (mainly), in " quasi-suspended animation", were found in organically poor sediments, up to 101.5 million years old, 250 feet below the seafloor in the South Pacific Gyre (SPG) ("the deadest spot in the ocean"), and could be the longest-living life forms ever found. Types * Obligate aerobes need oxygen to grow. In a process known as cellular respiration, these organisms use oxygen to oxidize substrates (for example sugars and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pathogenic Bacterium
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 many are 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 considered part of the gut flora, with a few hundred species present in each individual human's 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 speciall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid-fast
Acid-fastness is a physical property of certain bacterial and eukaryotic cells, as well as some sub-cellular structures, specifically their resistance to decolorization by acids during laboratory staining procedures. Once stained as part of a sample, these organisms can resist the acid and/or ethanol-based decolorization procedures common in many staining protocols, hence the name ''acid-fast''. The mechanisms of acid-fastness vary by species although the most well-known example is in the genus ''Mycobacterium'', which includes the species responsible for tuberculosis and leprosy. The acid-fastness of ''Mycobacteria'' is due to the high mycolic acid content of their cell walls, which is responsible for the staining pattern of poor absorption followed by high retention. Some bacteria may also be partially acid-fast, such as ''Nocardia''. Acid-fast organisms are difficult to characterize using standard microbiological techniques, though they can be stained using concentrated dyes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motility
Motility is the ability of an organism to move independently using metabolism, metabolic energy. This biological concept encompasses movement at various levels, from whole organisms to cells and subcellular components. Motility is observed in animals, microorganisms, and even some plant structures, playing crucial roles in activities such as foraging, reproduction, and cellular functions. It is genetically determined but can be influenced by environmental factors. In multicellular organisms, motility is facilitated by systems like the Nervous system, nervous and Human musculoskeletal system, musculoskeletal systems, while at the cellular level, it involves mechanisms such as amoeboid movement and flagellar propulsion. These cellular movements can be directed by external stimuli, a phenomenon known as taxis. Examples include chemotaxis (movement along chemical gradients) and phototaxis (movement in response to light). Motility also includes physiological processes like gastroi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endospore
An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Bacillota. The name "endospore" is suggestive of a spore or seed-like form (''endo'' means 'within'), but it is not a true spore (i.e., not an offspring). It is a stripped-down, dormant form to which the bacterium can reduce itself. Endospore formation is usually triggered by a lack of nutrients, and usually occurs in Gram-positive bacteria. In endospore formation, the bacterium divides within its cell wall, and one side then engulfs the other. Endospores enable bacteria to lie dormant for extended periods, even centuries. There are many reports of spores remaining viable over 10,000 years, and revival of spores millions of years old has been claimed. There is one report of viable spores of '' Bacillus marismortui'' in salt crystals approximately 25 million years old. When the environment becomes more favorable, the endospore can reactivate itself into a vegetative state. Mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleomorphism (microbiology)
In microbiology, pleomorphism (from Ancient Greek , ''pléō'', "more", and , ''morphḗ'', form), also pleiomorphism, is the ability of some microorganisms to alter their morphology, biological functions or reproductive modes in response to environmental conditions. Pleomorphism has been observed in some members of the Deinococcaceae family of bacteria. The modern definition of pleomorphism in the context of bacteriology is based on ''variation'' of morphology or functional methods of the individual cell, rather than a heritable ''change'' of these characters as previously believed. Bacteria In the first decades of the 20th century, the term "pleomorphism" was used to refer to the idea that bacteria change morphology, biological systems, or reproductive methods dramatically according to environmental cues. This claim was controversial among microbiologists of the time, and split them into two schools: the monomorphists, who opposed the claim, and the pleomorphists such as Antoi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leprosy Wade Fite Stain 100x
Leprosy, also known as Hansen's disease (HD), is a long-term infection by the bacteria ''Mycobacterium leprae'' or '' Mycobacterium lepromatosis''. Infection can lead to damage of the nerves, respiratory tract, skin, and eyes. This nerve damage may result in a lack of ability to feel pain, which can lead to the loss of parts of a person's extremities from repeated injuries or infection through unnoticed wounds. An infected person may also experience muscle weakness and poor eyesight. Leprosy symptoms may begin within one year, but for some people symptoms may take 20 years or more to occur. Leprosy is spread between people, although extensive contact is necessary. Leprosy has a low pathogenicity, and 95% of people who contract or who are exposed to ''M. leprae'' do not develop the disease. Spread is likely through a cough or contact with fluid from the nose of a person infected by leprosy. Genetic factors and immune function play a role in how easily a person catches the di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clofazimine
Clofazimine, sold under the brand name Lamprene, is a medication used together with rifampicin and dapsone to treat leprosy. It is specifically used for multibacillary (MB) leprosy and erythema nodosum leprosum, and its discovery greatly improved the overall efficiency of the treatment. Evidence is insufficient to support its use in other conditions, though a retrospective study found it 95% effective in the treatment of ''Mycobacterium avium'' complex (MAC) when administered together with a macrolide and ethambutol, as well as the drugs amikacin and clarithromycin. However, in the United States, clofazimine is currently considered an orphan drug, is unavailable in pharmacies, and its use in the treatment of MAC is overseen by the Food and Drug Administration. It is taken orally. Common side effects include abdominal pain, diarrhea, itchiness, dry skin, and change in skin color. It can also cause swelling of the lining of the gastrointestinal tract, increased blood sugar, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
