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Chlamydophila
''Chlamydophila'' is a controversial bacterial genus belonging to the family Chlamydiaceae. Taxonomy All Chlamydiota are anaerobic bacteria with a biphasic developmental lifecycle that depends on obligately intracellular growth in eukaryotic host cells. ''Chlamydophila'' was recognized by a number of scientists in 1999, with six species in ''Chlamydophila'' and three in the original genus, ''Chlamydia''. This was immediately seen as controversial. In 2015 the ''Chlamydophila'' species were reclassified as ''Chlamydia''. The history of the classification and reclassification is as follows. Earlier criteria for differentiation of chlamydial species did not always work well. For example, at that time genus ''C. psittaci'' was distinguished from '' C. trachomatis'' by sulfadiazine resistance, although not all strains identified as ''C. psittaci'' at the time were resistant, and '' C. pneumoniae'' was classified by its appearance under electron microscopy (EM) and its ability t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydophila Psittaci
''Chlamydia psittaci'' is a lethal intracellular parasite, intracellular bacterial species that may cause Endemism, endemic Bird, avian chlamydiosis, epizootic outbreaks in mammals, and respiratory psittacosis in humans. Potential hosts include feral birds and domesticated poultry, as well as cattle, pigs, sheep, and horses. ''C. psittaci'' is transmitted by inhalation, contact, or ingestion among birds and to mammals. Psittacosis in birds and in humans often starts with Influenza-like illness, flu-like symptoms and becomes a life-threatening pneumonia. Many strains remain virus latency, quiescent in birds until activated by stress. Birds are excellent, highly mobile vector (epidemiology), vectors for the distribution of chlamydia infection, because they feed on, and have access to, the detritus of infected animals of all sorts. ''C. psittaci'' in birds is often systemic disease, systemic, and infections can be inapparent, severe, acute, or chronic with intermittent shedding. ''C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydia (bacterium)
''Chlamydia'' is a genus of pathogenic Gram-negative bacteria that are obligate intracellular parasites. ''Chlamydia'' infections are the most common bacterial sexually transmitted diseases in humans and are the leading cause of infectious blindness worldwide. Species include ''Chlamydia trachomatis'' (a human pathogen), '' Ch. suis'' (affects only swine), and '' Ch. muridarum'' (affects only mice and hamsters). Humans mainly contract '' Ch. trachomatis'', '' Ch. pneumoniae'', ''Ch. abortus'', and '' Ch. psittaci''. Classification Because of ''Chlamydia''s unique developmental cycle, it was taxonomically classified in a separate order. ''Chlamydia'' is part of the order Chlamydiales, family Chlamydiaceae. In the early 1990s six species of ''Chlamydia'' were known. A major re-description of the Chlamydiales order in 1999, using the then new techniques of DNA analysis, split three of the species from the genus ''Chlamydia'' and reclassified them in the then newly created genus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydophila Felis
''Chlamydia felis'' (formerly ''Chlamydophila felis'' and before that ''Chlamydia psittaci'' var. ''felis'') is a Gram-negative, obligate intracellular bacterial pathogen that infects cats. It is endemic among domestic cats worldwide, primarily causing inflammation of feline conjunctiva, rhinitis and respiratory problems. ''C. felis'' can be recovered from the stomach and reproductive tract. Zoonotic infection of humans with ''C. felis'' has been reported. Strains FP Pring and FP Cello have an extrachromosomal plasmid, whereas the FP Baker strain does not. FP Cello produces lethal disease in mice, whereas the FP Baker does not. An attenuated FP Baker strain, and an attenuated 905 strain, are used as live vaccines for cats. Taxonomy and Phylogeny The genus ''Chlamydia'' contains the species '' C. trachomatis, C. psittaci, C. abortus, C. felis, C. muridarum, C. suis, C. caviae, C. pecorum,'' and '' C. pneumoniae.'' However, there is some dispute that some of these species, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydiota
The Chlamydiota (synonym Chlamydiae) are a bacterial phylum and class whose members are remarkably diverse, including pathogens of humans and animals, symbionts of ubiquitous protozoa, and marine sediment forms not yet well understood. All of the Chlamydiota that humans have known about for many decades are obligate intracellular bacteria; in 2020 many additional Chlamydiota were discovered in ocean-floor environments, and it is not yet known whether they all have hosts. Historically it was believed that all Chlamydiota had a peptidoglycan-free cell wall, but studies in the 2010s demonstrated a detectable presence of peptidoglycan, as well as other important proteins. Among the Chlamydiota, all of the ones long known to science grow only by infecting eukaryotic host cells. They are as small as or smaller than many viruses. They are ovoid in shape and stain Gram-negative. They are dependent on replication inside the host cells; thus, some species are termed obligate intracellula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydophila Pecorum
''Chlamydia pecorum'', also known as Chlamydophila pecorum is a species of Chlamydiaceae that originated from ruminants, such as cattle, sheep and goats. It has also infected koalas and swine. ''C. pecorum'' strains are serologically and pathogenically diverse. In the koalas, ''C. pecorum'' causes infections in the reproductive systems and urinary tract, as well as pneumonia, infertility, and death. It is considered one of the most important infectious diseases that currently plagues koalas. C.pecorum is the most common chlamydial species to infect koalas and is the most pathogenic. In other animals, ''C. pecorum'' has been associated with abortion, conjunctivitis, encephalomyelitis, enteritis, arthritis, and polyarthritis Polyarthritis is any type of arthritis that involves 5 or more joints simultaneously. It is usually associated with autoimmune conditions and may be experienced at any age and is not sex specific. Causes Polyarthritis is most often caused by an au .... S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydophila Pneumoniae
''Chlamydia pneumoniae'' is a species of ''Chlamydia (genus), Chlamydia'', an Obligate intracellular parasite, obligate intracellular bacterium that infects humans and is a major cause of pneumonia. It was known as the Taiwan acute respiratory agent (TWAR) from the names of the two original isolates – Taiwan (TW-183) and an acute respiratory isolate designated AR-39. Briefly, it was known as ''Chlamydophila pneumoniae,'' and that name is used as an alternate in some sources. In some cases, to avoid confusion, both names are given. ''Chlamydia pneumoniae'' has a complex life cycle and must infect another cell to reproduction, reproduce; thus, it is classified as an Obligate intracellular parasite, obligate intracellular pathogen. The full genome sequence for ''C. pneumoniae'' was published in 1999. It also infects and causes disease in koalas, emerald tree boas (''Corallus caninus''), iguanas, chameleons, frogs, and turtles. The first known case of infection with ''C. pneu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydiaceae
The Chlamydiaceae are a family of gram-negative bacteria that belongs to the phylum Chlamydiota, order Chlamydiales. Chlamydiaceae species express the family-specific lipopolysaccharide epitope αKdo-(2→8)-αKdo-(2→4)-αKdo (previously called the genus-specific epitope). Chlamydiaceae ribosomal RNA genes all have at least 90% DNA sequence identity. Chlamydiaceae species have varying inclusion morphology, varying extrachromosomal plasmid content, and varying sulfadiazine resistance. The family Chlamydiaceae currently includes one genus and one candidate genus: ''Chlamydia'' and ''candidatus Clavochlamydia''. ''Chlamydia'' Three species belong to ''Chlamydia'': ''C. trachomatis'', ''C. muridarum'', and ''C. suis''. ''C. trachomatis'' has been found only in humans, ''C. muridarum'' in hamsters and mice (family Muridae), and ''C. suis'' in swine. ''Chlamydia'' species produce a small amount of detectable glycogen and have two ribosomal operons. ''Chlamydia trachomat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydophila Caviae
''Chlamydia caviae'' is a bacterium that can be recovered from the conjunctiva of Guinea pigs suffering from ocular inflammation and eye discharge. It is also possible to infect the genital tract of Guinea pigs with ''C. caviae'' and elicit a disease that is very similar to human Chlamydia trachomatis infection. ''C. caviae'' infects primarily the mucosal epithelium and is not invasive. ''C. caviae'' is markedly specific for Guinea pigs, as attempts to infect mice, hamsters, rabbits and gerbils have been unsuccessful, except for one experimentally infected gerbil. The five known ''C. caviae'' isolates are indistinguishable, based on ompA gene sequence. Genome structure ''C. caviae'' has a relatively small genome that contains 1.17 Mbp with 998 protein coding genes. Additionally, ''C. caviae'' strain GPIC contains an extrachromosomal plasmid A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can repl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydophila Abortus
''Chlamydia abortus'' is a species in Chlamydiota that causes abortion and fetal death in mammals, including humans. ''Chlamydia abortus'' was renamed in 1999 as ''Chlamydophila psittaci'' along with all Chlamydiota except ''Chlamydia trachomatis''. This was based on a lack of evident glycogen production and on resistance to the antibiotic sulfadiazine. In 1999 ''C. psittaci'' and ''C. abortus'' were recognized as distinct species based on differences of pathogenicity and DNA–DNA hybridization. In 2015, this new name was reverted to Chlamydia. In humans There are approximately one or two cases of chlamydiosis diagnosis in pregnant women in the United Kingdom per year. Typically transmission occurs from contact with livestock who have recently given birth. The true prevalence in humans is unknown because Serology, serological antibody tests are unable to distinguish between ''C. abortus'' and other more common species such as ''Chlamydia trachomatis''. In other animals ''Chla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
23S Ribosomal RNA
The 23S rRNA is a 2,904 nucleotide long (in '' E. coli'') component of the large subunit ( 50S) of the bacterial/archean ribosome and makes up the peptidyl transferase center (PTC). The 23S rRNA is divided into six secondary structural domains titled I-VI, with the corresponding 5S rRNA being considered domain VII. The ribosomal peptidyl transferase activity resides in domain V of this rRNA, which is also the most common binding site for antibiotics that inhibit translation, making it a target for ribosomal engineering. A well-known member of this antibiotic class, chloramphenicol, acts by inhibiting peptide bond formation, with recent 3D-structural studies showing two different binding sites depending on the species of ribosome. Numerous mutations in domains of the 23S rRNA with Peptidyl transferase activity have resulted in antibiotic resistance. 23S rRNA genes typically have higher sequence variations, including insertions and/or deletions, compared to other rRNAs. The euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
16S Ribosomal RNA
16 S ribosomal RNA (or 16 S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome (SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure. The genes coding for it are referred to as 16S rRNA gene and are used in reconstructing phylogenies, due to the slow rates of evolution of this region of the gene. Carl Woese and George E. Fox were two of the people who pioneered the use of 16S rRNA in phylogenetics in 1977. Multiple sequences of the 16S rRNA gene can exist within a single bacterium. Functions * Like the large (23S) ribosomal RNA, it has a structural role, acting as a scaffold defining the positions of the ribosomal proteins. * The 3-end contains the anti- Shine-Dalgarno sequence, which binds upstream to the AUG start codon on the mRNA. The 3-end of 16S RNA binds to the proteins S1 and S21 which are known to be involved in initiation of protein synthesis * Interacts with 23S, aiding in the binding of the two ribosomal s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antigen
In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune response. The term ''antigen'' originally referred to a substance that is an antibody generator. Antigens can be proteins, peptides (amino acid chains), polysaccharides (chains of monosaccharides/simple sugars), lipids, or nucleic acids. Antigens are recognized by antigen receptors, including antibodies and T-cell receptors. Diverse antigen receptors are made by cells of the immune system so that each cell has a specificity for a single antigen. Upon exposure to an antigen, only the lymphocytes that recognize that antigen are activated and expanded, a process known as clonal selection. In most cases, an antibody can only react to and bind one specific antigen; in some instances, however, antibodies may cross-react and bind more than one antigen. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
