|
Chlamydiae
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] |
Chlamydia
Chlamydia, or more specifically a chlamydia infection, is a sexually transmitted infection caused by the bacterium ''Chlamydia trachomatis''. Most people who are infected have no symptoms. When symptoms do appear they may occur only several weeks after infection; the incubation period between exposure and being able to infect others is thought to be on the order of two to six weeks. Symptoms in women may include vaginal discharge or burning with urination. Symptoms in men may include discharge from the penis, burning with urination, or pain and swelling of one or both testicles. The infection can spread to the upper genital tract in women, causing pelvic inflammatory disease, which may result in future infertility or ectopic pregnancy. Chlamydia infections can occur in other areas besides the genitals, including the anus, eyes, throat, and lymph nodes. Repeated chlamydia infections of the eyes that go without treatment can result in trachoma, a common cause of blindness in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waddliaceae
''Waddlia'' is a genus of bacteria in its own family, Waddliaceae. Species in this genus have a ''Chlamydia''-like cycle of replication and their ribosomal RNA genes are 80–90% identical to ribosomal genes in the Chlamydiaceae. The type species is ''Waddlia chondrophila'' strain WSU 86-1044T, which was isolated from the tissues of a first-trimester aborted bovine fetus. Isolated in 1986, this species was originally characterized as a ''Rickettsia''. DNA sequencing of the ribosomal genes corrected the characterization. Another ''W. chondrophila'' strain, 2032/99, was found along with ''Neospora caninum'' in a septic stillborn calf. ''Waddlia chondrophila'' may be linked to miscarriages in pregnant women. A study found ''Waddlia chondrophila'' present in the placenta and vagina of 32 women, 10 of which who had miscarriages. It is hypothesized that the bacterial grows in placental cells, damaging the placenta. The species ''Waddlia malaysiensis'' G817 has been proposed. ''W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydiales
The bacterial order Chlamydiales includes only obligately intracellular bacteria that have a chlamydia-like developmental cycle of replication and at least 80% 16S rRNA or 23S rRNA gene sequence identity with other members of Chlamydiales. Chlamydiales live in animals, insects, and protozoa. Currently, the order Chlamydiales includes the families Chlamydiaceae, Simkaniaceae, and Waddliaceae, which have Gram-negative extracellular infectious bodies (EBs), and Parachlamydiaceae, which has variable Gram staining of EBs. The family Rhabdochlamydiaceae has been proposed. Phylogeny Taxonomy The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI) * Family " Actinochlamydiaceae" Steigen et al. 2013 ** ?"''Ca.'' Actinochlamydia" Steigen et al. 2013 * Family " Clavichlamydiaceae" Horn 2011 ** "''Ca.'' Clavichlamydia" corrig. Karlsen et al. 2008 * Family " Criblamydiaceae" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlamydia Trachomatis
''Chlamydia trachomatis'' (), commonly known as chlamydia, is a bacterium that causes chlamydia, which can manifest in various ways, including: trachoma, lymphogranuloma venereum, nongonococcal urethritis, cervicitis, salpingitis, pelvic inflammatory disease. ''C. trachomatis'' is the most common infectious cause of blindness and the most common sexually transmitted bacterium. Different types of ''C. trachomatis'' cause different diseases. The most common strains cause disease in the genital tract, while other strains cause disease in the eye or lymph nodes. Like other ''Chlamydia'' species, the ''C. trachomatis'' life cycle consists of two morphologically distinct life stages: elementary bodies and reticulate bodies. Elementary bodies are spore-like and infectious, whereas reticulate bodies are in the replicative stage and are seen only within host cells. Description ''Chlamydia trachomatis'' is a gram-negative bacterium that can replicate only within a host cell. Over the cour ... [...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] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898,Dimmock p. 4 more than 9,000 virus species have been described in detail of the millions of types of viruses in the environment. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, or ''virions'', consisting of (i) the genetic material, i. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryotic
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). Euka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism ''Escherichia coli'', as well as many pathogenic bacteria, such as ''Pseudomonas aeruginosa'', ''Chlamydia trachomatis'', and ''Yersinia pestis''. They are a significant medical challenge as their outer membrane protects them from many antibiotics (including penicillin), detergents that would normally damage the inner cell membrane, and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intracellular Parasite
Intracellular parasites are microparasites that are capable of growing and reproducing inside the cells of a host. Types of parasites There are two main types of intracellular parasites: Facultative and Obligate. Facultative intracellular parasites are capable of living and reproducing in or outside of host cells. Obligate intracellular parasites, on the other hand, need a host cell to live and reproduce. Many of these types of cells require specialized host types, and invasion of host cells occurs in different ways. Facultative Facultative intracellular parasites are capable of living and reproducing either inside or outside cells. Bacterial examples include: *''Bartonella henselae'' *''Francisella tularensis'' *''Listeria monocytogenes'' * ''Salmonella'' Typhi *''Brucella'' *''Legionella'' *''Mycobacterium'' *'' Nocardia'' *''Neisseria'' *''Rhodococcus equi'' *''Yersinia'' *''Staphylococcus aureus'' Fungal examples include: *''Histoplasma capsulatum''. *''Cryptococcus neofo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inclusion Body
Inclusion bodies are aggregates of specific types of protein found in neurons, a number of tissue cells including red blood cells, bacteria, viruses, and plants. Inclusion bodies of aggregations of multiple proteins are also found in muscle cells affected by inclusion body myositis and hereditary inclusion body myopathy. Inclusion bodies in neurons may be accumulated in the cytoplasm or nucleus, and are associated with many neurodegenerative diseases. Inclusion bodies in neurodegenerative diseases are aggregates of misfolded proteins (aggresomes) and are hallmarks of many of these diseases, including Lewy bodies in Lewy body dementias, and Parkinson's disease, neuroserpin inclusion bodies called Collins bodies in familial encephalopathy with neuroserpin inclusion bodies, inclusion bodies in Huntington's disease, Papp-Lantos inclusions in multiple system atrophy, and various inclusion bodies in frontotemporal dementia including Pick bodies. Bunina bodies in motor neurons are a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medicine
Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness. Contemporary medicine applies biomedical sciences, biomedical research, genetics, and medical technology to diagnose, treat, and prevent injury and disease, typically through pharmaceuticals or surgery, but also through therapies as diverse as psychotherapy, external splints and traction, medical devices, biologics, and ionizing radiation, amongst others. Medicine has been practiced since prehistoric times, and for most of this time it was an art (an area of skill and knowledge), frequently having connections to the religious and philosophical beliefs of local culture. For example, a medicine man would apply herbs and say prayers for healing, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuole
A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain cases they may contain solids which have been engulfed. Vacuoles are formed by the fusion of multiple membrane vesicles and are effectively just larger forms of these. The organelle has no basic shape or size; its structure varies according to the requirements of the cell. Discovery Contractile vacuoles ("stars") were first observed by Spallanzani (1776) in protozoa, although mistaken for respiratory organs. Dujardin (1841) named these "stars" as ''vacuoles''. In 1842, Schleiden applied the term for plant cells, to distinguish the structure with cell sap from the rest of the protoplasm. In 1885, de Vries named the vacuole membrane as tonoplast. Function The function and signifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
