|
Spo11
Spo11 is a protein that in humans is encoded by the ''SPO11'' gene. Spo11, in a complex with mTopVIB, creates double strand breaks to initiate meiotic recombination. Its active site contains a tyrosine which ligates and dissociates with DNA to promote break formation. One Spo11 protein is involved per strand of DNA, thus two Spo11 proteins are involved in each double stranded break event. Genetic exchange between two DNA molecules by homologous recombination can begin with a break in both strands of DNA—called a double-strand break—and recombination is started by an endonuclease enzyme that cuts the DNA molecule that "receives" the exchanged DNA. In meiosis the enzyme is SPO11, which is related to DNA topoisomerases. Topoisomerases change DNA by transiently breaking one or both strands, passing the unbroken DNA strand or strands through the break and repairing the break; the broken ends of the DNA are covalently linked to topoisomerase. SPO11 is similarly attached to the DN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homologous Recombination
Homologous recombination is a type of genetic recombination in which genetic information is exchanged between two similar or identical molecules of double-stranded or single-stranded nucleic acids (usually DNA as in Cell (biology), cellular organisms but may be also RNA in viruses). Homologous recombination is widely used by cells to accurately DNA repair, repair harmful DNA breaks that occur on both strands of DNA, known as double-strand breaks (DSB), in a process called homologous recombinational repair (HRR). Homologous recombination also produces new combinations of DNA sequences during meiosis, the process by which eukaryotes make gamete cells, like sperm and ovum, egg cells in animals. These new combinations of DNA represent genetic variation in offspring, which in turn enables populations to Adaptation, adapt during the course of evolution. Homologous recombination is also used in horizontal gene transfer to exchange genetic material between different strains and species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meiosis
Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one copy of each chromosome (haploid). Additionally, prior to the division, genetic material from the paternal and maternal copies of each chromosome is crossed over, creating new combinations of code on each chromosome. Later on, during fertilisation, the haploid cells produced by meiosis from a male and a female will fuse to create a zygote, a cell with two copies of each chromosome. Errors in meiosis resulting in aneuploidy (an abnormal number of chromosomes) are the leading known cause of miscarriage and the most frequent genetic cause of developmental disabilities. In meiosis, DNA replication is followed by two rounds of cell division to produce four daughter cells, each with half the number of chromosomes as the original parent cell. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amoeba
An amoeba (; less commonly spelled ameba or amœba; : amoebas (less commonly, amebas) or amoebae (amebae) ), often called an amoeboid, is a type of Cell (biology), cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopodia, pseudopods. Amoebae do not form a single Taxonomy (biology), taxonomic group; instead, they are found in every major Lineage (evolution), lineage of eukaryote, eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals. Microbiologists often use the terms "amoeboid" and "amoeba" interchangeably for any organism that exhibits amoeboid movement. In older classification systems, most amoebae were placed in the Class (biology), class or subphylum Sarcodina, a grouping of Unicellular organism, single-celled organisms that possess pseudopods or move by protoplasmic flow. However, molecular phylogenetic studies have shown that Sarcodina is not a monophyletic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Reproduction
Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote that develops into an organism composed of cells with two sets of chromosomes ( diploid). This is typical in animals, though the number of chromosome sets and how that number changes in sexual reproduction varies, especially among plants, fungi, and other eukaryotes. In placental mammals, sperm cells exit the penis through the male urethra and enter the vagina during copulation, while egg cells enter the uterus through the oviduct. Other vertebrates of both sexes possess a cloaca for the release of sperm or egg cells. Sexual reproduction is the most common life cycle in multicellular eukaryotes, such as animals, fungi and plants. Sexual reproduction also occurs in some unicellular eukaryotes. Sexual reproduction does not occur in pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polysphondylium Pallidum
''Polysphondylium pallidum'' is a species of cellular slime mould, a member of the phylum Mycetozoa. Taxonomy The lectotype of ''Polysphondylium pallidum'' was first described from Liberia where it was growing on the dung of an ass. This slime mould has a world-wide distribution but there has been found to be variation between different samples and in a taxonomic revision in 2008, Kawakami and Hagiwara determined that some specimens originally described as ''P. pallidum'' were a different species, '' Polysphondylium album''. Biology ''Polysphondylium pallidum'' starts life as a single-celled amoeboid protist. Like other slime moulds, it lives in soil, dung, leaf litter and other decaying organic materials. It is known as a myxamoeba and feeds on bacteria and fungal spores. In favourable, damp conditions it may reproduce sexually while in drier conditions, asexual reproduction is more likely. The myxamoebae release a chemical agent, acrasin, which guides other slime mould cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dictyostelium Discoideum
''Dictyostelium discoideum'' is a species of soil-dwelling Amoeboid, amoeba belonging to the phylum Amoebozoa, infraphylum Mycetozoa. Commonly referred to as slime mold, ''D. discoideum'' is a eukaryote that transitions from a collection of unicellular amoebae into a multicellular slug and then into a fruiting body within its lifetime. Its unique asexual Biological life cycle, life cycle consists of four stages: vegetative, aggregation, migration, and culmination. The life cycle of ''D. discoideum'' is relatively short, which allows for timely viewing of all stages. The cells involved in the life cycle undergo movement, chemical signaling, and development, which are applicable to human cancer research. The simplicity of its life cycle makes ''D. discoideum'' a valuable model organism to study genetic, cellular, and biochemical processes in other organisms. Natural habitat and diet In the wild, ''D. discoideum'' can be found in soil and moist leaf litter. Its primary diet consists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acytostelium
''Acytostelium'' is a genus of dictyostelid. The genus ''Acytostelium'' inhabit surface humus and leaf mold of forest soils and are widely distributed in different forests of the world. Species include: * '' Acytostelium aggregatum'' Cavender & Vadell 2000 * '' Acytostelium amazonicum'' Cavender & Vadell 2000 * '' Acytostelium anastomosans'' Cavender et al. 2005 * '' Acytostelium digitatum'' Cavender & Vadell 2000 * '' Acytostelium irregularosporum'' Hagiw. 1971 * '' Acytostelium leptosomum'' Raper 1956 * '' Acytostelium longisorophorum'' Cavender et al. 2005 * '' Acytostelium magniphorum'' Cavender & Vadell 2000 * '' Acytostelium magnisorum'' Cavender et al. 2005 * '' Acytostelium minutissimum'' Cavender & Vadell 2000 * '' Acytostelium pendulum'' Cavender & Vadell 2000 * '' Acytostelium reticulatum'' Cavender & Vadell 2000 * '' Acytostelium serpentarium'' Cavender et al. 2005 * '' Acytostelium singulare'' Cavender et al. 2005 * '' Acytostelium subglobosum'' Cavender 1976 Refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polysphondylium
''Polysphondylium'' is a genus of cellular slime mold, including the species ''Polysphondylium pallidum''. The genus was circumscribed by German mycologist Julius Oscar Brefeld in 1884. Species *'' Polysphondylium acuminatum'' Vadell & Cavender 1998 nom. inv. *'' Polysphondylium aureum'' Hodgson & Wheller 2001 nom. inv. *'' Polysphondylium fuscans'' Perrigo & Romeralo 2012 *'' Polysphondylium laterosorum'' (Cavender 1970) Baldauf, Sheikh & Thulin 2017 *'' Polysphondylium patagonicum'' Vadell et al. 2011 *'' Polysphondylium violaceum'' Brefeld 1885 See also *''Dictyostelium ''Dictyostelium'' is a genus of single- and multi-celled eukaryotic, phagotrophic bacterivores. Though they are Protista and in no way fungal, they traditionally are known as "slime molds". They are present in most terrestrial ecosystems a ...'' so-called cellular slime mold. References Dictyostelid genera Mycetozoa Taxa named by Julius Oscar Brefeld {{Amoebozoa-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dictyostelium
''Dictyostelium'' is a genus of single- and multi-celled eukaryotic, phagotrophic bacterivores. Though they are Protista and in no way fungal, they traditionally are known as "slime molds". They are present in most terrestrial ecosystems as a normal and often abundant component of the soil microflora, and play an important role in the maintenance of balanced bacterial populations in soils. The genus ''Dictyostelium'' is in the order Dictyosteliida, the so-called cellular slime molds or social amoebae. In turn the order is in the infraphylum Mycetozoa. Members of the order are of great theoretical interest in biology because they have aspects of both unicellularity and multicellularity. The individual cells in their independent phase are common on organic detritus or in damp soils and caves. In this phase they are amoebae. Typically, the amoebal cells grow separately and wander independently, feeding mainly on bacteria. However, they interact to form multi-cellular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
