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Pronuclear Transfer
A pronucleus (: pronuclei) denotes the Cell nucleus, nucleus found in either a sperm or egg cell during the process of Fertilisation, fertilization. The Spermatozoon, sperm cell undergoes a transformation into a pronucleus after entering the egg cell but prior to the fusion of the genetic material of both the sperm and egg. In contrast, the egg cell possesses a pronucleus once it becomes haploid, not upon the arrival of the sperm cell. Haploid cells, such as sperm and egg cells in humans, carry half the number of chromosomes present in somatic cells, with 23 chromosomes compared to the 46 found in somatic cells. It is noteworthy that the male and female pronuclei do not physically merge, although their genetic material does. Instead, their membranes dissolve, eliminating any barriers between the male and female chromosomes, facilitating the combination of their chromosomes into a single diploid nucleus in the resulting embryo, which contains a complete set of 46 chromosomes. The p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staining
Staining is a technique used to enhance contrast in samples, generally at the Microscope, microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissue (biology), tissues), in cytology (microscopic study of cell (biology), cells), and in the medical fields of histopathology, hematology, and cytopathology that focus on the study and diagnoses of diseases at the microscopic level. Stains may be used to define biological tissues (highlighting, for example, muscle fibers or connective tissue), cell (biology), cell populations (classifying different blood cells), or organelles within individual cells. In biochemistry, it involves adding a class-specific (DNA, proteins, lipids, carbohydrates) dye to a substrate to qualify or quantify the presence of a specific compound. Staining and fluorescent tagging can serve similar purposes. Biological staining is also used to mark cells in flow cytometry, and to flag proteins or nucleic acids in gel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinblastine
Vinblastine, sold under the brand name Velban among others, is a chemotherapy medication, typically used with other medications, to treat a number of types of cancer. This includes Hodgkin's lymphoma, non-small-cell lung cancer, bladder cancer, brain cancer, melanoma, and testicular cancer. It is given by injection into a vein. Most people experience some side effects. Commonly it causes a change in sensation, constipation, weakness, loss of appetite, and headaches. Severe side effects include low blood cell counts and shortness of breath. It should not be given to people who have a current bacterial infection. Use during pregnancy will likely harm the baby. Vinblastine works by blocking cell division. Vinblastine was isolated in 1958. An example of a natural herbal remedy that has since been developed into a conventional medicine, vinblastine was originally obtained from the Madagascar periwinkle. It is on the World Health Organization's List of Essential Medicines. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrosome
In cell biology, the centrosome (Latin centrum 'center' + Greek sōma 'body') (archaically cytocentre) is an organelle that serves as the main microtubule organizing center (MTOC) of the animal cell, as well as a regulator of cell-cycle progression. The centrosome provides structure for the cell. It is thought to have evolved only in the metazoan lineage of eukaryotic cells. Fungi and plants lack centrosomes and therefore use other structures to organize their microtubules. Although the centrosome has a key role in efficient mitosis in animal cells, it is not essential in certain fly and flatworm species. Centrosomes are composed of two centrioles arranged at right angles to each other, and surrounded by a dense, highly structured mass of protein termed the pericentriolar material (PCM). The PCM contains proteins responsible for microtubule nucleation and anchoring — including γ-tubulin, pericentrin and ninein. In general, each centriole of the centrosome is based on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoplasm
The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell and contained within the nuclear membrane is termed the nucleoplasm. The main components of the cytoplasm are the cytosol (a gel-like substance), the cell's internal sub-structures, and various cytoplasmic inclusions. In eukaryotes the cytoplasm also includes the nucleus, and other membrane-bound organelles.The cytoplasm is about 80% water and is usually colorless. The submicroscopic ground cell substance, or cytoplasmic matrix, that remains after the exclusion of the cell organelles and particles is groundplasm. It is the hyaloplasm of light microscopy, a highly complex, polyphasic system in which all resolvable cytoplasmic elements are suspended, including the larger organelles such as the ribosomes, mitochondria, plant plasti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microtubules
Microtubules are polymers of tubulin that form part of the cytoskeleton and provide structure and shape to eukaryotic cells. Microtubules can be as long as 50 micrometres, as wide as 23 to 27 nm and have an inner diameter between 11 and 15 nm. They are formed by the polymerization of a dimer of two globular proteins, alpha and beta tubulin into protofilaments that can then associate laterally to form a hollow tube, the microtubule. The most common form of a microtubule consists of 13 protofilaments in the tubular arrangement. Microtubules play an important role in a number of cellular processes. They are involved in maintaining the structure of the cell and, together with microfilaments and intermediate filaments, they form the cytoskeleton. They also make up the internal structure of cilia and flagella. They provide platforms for intracellular transport and are involved in a variety of cellular processes, including the movement of secretory vesicles, organel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelvetia
''Pelvetia canaliculata'', the channelled wrack, is a very common brown alga (Phaeophyceae) found on the rocks of the upper shores of Europe. It is the only species remaining in the monotypic genus ''Pelvetia''. In 1999, the other members of this genus were reclassified as '' Silvetia'' due to differences of oogonium structure and of nucleic acid sequences of the rDNA. Description ''Pelvetia'' grows to a maximum length of in dense tufts, the fronds being deeply channeled on one side: the channels and a mucus layer help prevent the seaweed drying (desiccation) when the tide is out. It is irregularly dichotomously branched with terminal receptacles, and is dark brown in color. Each branch is of uniform width and without a midrib. The receptacles are forked at the tips. It is distinguished from other large brown algae by the channels along the frond. It has no mid-rib, no air-vesicles and no cryptostomata. It forms the uppermost zone of algae on the shore growing at or above hig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaginal Fluid
Vaginal discharge is a mixture of liquid, cells, and bacteria that lubricate and protect the vagina. This mixture is constantly produced by the cells of the vagina and cervix, and it exits the body through the vaginal opening. The composition, quality, and amount of discharge varies between individuals, and can vary throughout the menstrual cycle and throughout the stages of sexual and reproductive development. Normal vaginal discharge may have a thin, watery consistency or a thick, sticky consistency, and it may be clear or white in color. Normal vaginal discharge may be large in volume but typically does not have a strong odor, nor is it typically associated with itching or pain. While most discharge is considered physiologic (represents normal functioning of the body), some changes in discharge can reflect infection or other pathological processes. Infections that may cause changes in vaginal discharge include vaginal yeast infections, bacterial vaginosis, and sexually trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testes
A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of androgens, primarily testosterone. The release of testosterone is regulated by luteinizing hormone (LH) from the anterior pituitary gland. Sperm production is controlled by follicle-stimulating hormone (FSH) from the anterior pituitary gland and by testosterone produced within the gonads. Structure Appearance Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry, in which one testicle extends farther down into the scrotum than the other, is common. This is because of the differences in the vasculature's anatomy. For 85% of men, the right testis hangs lower than the left one. Measurement and volume The volume of the testicle can be estimated by palpating it and comparing it to ellipsoids (an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haploid Cell
Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, respectively, in each homologous chromosome pair—the form in which chromosomes naturally exist. Somatic cells, tissues, and individual organisms can be described according to the number of sets of chromosomes present (the "ploidy level"): monoploid (1 set), diploid (2 sets), triploid (3 sets), tetraploid (4 sets), pentaploid (5 sets), hexaploid (6 sets), heptaploid or septaploid (7 sets), etc. The generic term polyploid is often used to describe cells with three or more sets of chromosomes. Virtually all sexually reproducing organisms are made up of somatic cells that are diploid or greater, but ploidy level may vary widely between different organisms, between different tissues within the same organism, and at different stages in an org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Bodies
A polar body is a small haploid cell that is formed at the same time as an egg cell during oogenesis, but generally does not have the ability to be fertilized. It is named from its polar position in the egg. When certain diploid cells in animals undergo cytokinesis after meiosis to produce egg cells, they sometimes divide unevenly. Most of the cytoplasm is segregated into one daughter cell, which becomes the egg or ovum, while the smaller ''polar bodies'' only get a small amount of cytoplasm. They frequently die and disintegrate by apoptosis, but in some cases remain and can be important in the life cycle of the organism. Twinning ''Polar body twinning'' is a hypothesized form of twinning in meiosis, where one or more polar bodies do not disintegrate and are fertilized by sperm. Twinning would occur, in principle, if the egg cell and a polar body were both fertilized by separate sperms. However, even if fertilization occurred, further development would usually not occur becau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscar Hertwig
Oscar Hertwig (21 April 1849 in Friedberg – 25 October 1922 in Berlin) was a German embryologist and zoologist known for his research in developmental biology and evolution. Hertwig is credited as the first person to observe sexual reproduction at the cellular level, by looking at the cells of sea urchins under the microscope. Biography Hertwig was the elder brother of zoologist-professor Richard Hertwig (1850–1937). The Hertwig brothers were the most eminent scholars of Ernst Haeckel (and Carl Gegenbaur) from the University of Jena. They were independent of Haeckel's philosophical speculations but took his ideas in a positive way to widen their concepts in zoology. Initially, between 1879 and 1883, they performed embryological studies, especially on the theory of the coelom (1881), the fluid-filled body cavity. These problems were based on the phylogenetic theorems of Haeckel, i.e. the biogenic theory (German = biogenetisches Grundgesetz), and the " gastraea theory" ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
