Infobox Anatomy Name Oogenesis Latin GraySubject GrayPage Image Caption Precursor System Artery Vein Nerve Lymph MeshName MeshNumber DorlandsPre e 13 DorlandsSuf 12339107 Oogenesis , ovogenesis or o genesis IPAc en icon o . d n s s ref http www.merriam webster.com dictionary Oogenesis Merriam Webster Online Dictionary Definition Oogenesis ref is the creation of an ovum egg cell . It is the female form of gametogenesis the male equivalent is spermatogenesis . It involves the development of the various stages of the immature ova immature ovum . Oogenesis in mammals File Gray5.svg thumb 260px Diagram showing the reduction in number of the chromosomes in the process of maturation of the ovum . In mammal s, the first part of oogenesis starts in the germinal epithelium female germinal epithelium , which gives rise to the development of ovarian follicles , the functional unit of the ovary . Note that this process, important to all animal life cycles yet unlike all other instances ... . citation needed date April 2010 Oogenesis consists of several sub processes Oogenesis Oocytogenesis oocytogenesis , ootidogenesis , and finally maturation to form an ovum oogenesis proper ... Ovum The Creation of Oogonia The creation of oogonia traditionally doesn t belong to oogenesis ... Oogenesis At the start of the menstrual cycle, some 12 20 primary follicles begin to develop under ... hormone citation needed date May 2009 Oocytogenesis Oogenesis starts with the process of developing ... Oogenesis in non mammals Main Evolution of sexual reproduction Many protist s produce egg cells ... alga Fucus , all four egg cells survive oogenesis, which is an exception to the rule that generally only one product of female meiosis survives to maturity. In plant s, oogenesis occurs inside the female ... celled embryo sac within the ovule inside the Ovary plants ovary of the flower. Oogenesis occurs ... fr Ovogen se hy io Oogenezo id Oogenesis it Ovogenesi kk nl O genese pl Oogeneza ... more details
A gonocyte is a long lived germ cell responsible for gametogenesis , which is spermatogenesis in males, and oogenesis in females. Gonocytes include gametogonium gametogonia Spermatogonium spermatogonia and Oogonium oogonia , oocyte s, ootid s, and Ovum ova . The term often also refers to the primordial germ cells . It often does not include the short lived spermatocyte , spermatid , or sperm cells. Fact date April 2008 Reproductive physiology Category Developmental biology Category Reproductive system Category Germ cells cell biology stub pl Gonocyt ... more details
Karyosome refers to the chromatin material ref name Gould1972 cite book author Meredith C. Gould title Invertebrate oogenesis url http books.google.com books?id MWg82tI5 wC&pg PA126 accessdate 19 March 2012 year 1972 publisher Ardent Media isbn 978 0 8422 7030 4 page 126 ref inside cell nucleus when the cell is not undergoing mitotic division. ref http medical dictionary.thefreedictionary.com karyosome karyosome , Medical Dictionary ref References reflist Category Cell biology Cell biology stub ... more details
The cytoplasmic polyadenylation element CPE is a sequence element found in the 3 UTR 3 untranslated region of messenger RNA . Binding of CPEB CPE binding protein to this region promotes the extension of the polyadenylation polyadenine tail and, in general, activation of the mRNA for translation genetics protein translation . Among other functions, a prominent role for the CPE has been identified in oogenesis and spermatogenesis . ref name de Moor de Moor, C.H., and Richter, J.D. 1999 . Cytoplasmic polyadenylation mediate masking and unmasking of cyclin B1 mRNA. EMBO J. 18, 2294 2303. ref ref name Luitjens Luitjens C, Gallegos M, Kraemer B, Kimble J, Wickens M. 2000 . CPEB proteins control two key steps in spermatogenesis in C. elegans. Genes Dev 14 20 2596 609. ref References reflist genetics stub Category RNA ... more details
oocyte Main Oocyte The secondary oocyte is the cell that is formed by meiosis I in oogenesis. ref ... o o0086200.html yourdictionary ref In oogenesis, it doesn t really have any significance in itself ... more details
Trudi Sch pbach full name Gertrud Sch pbach published name Trudi Sch pbach is a Switzerland Swiss United States American Molecular biology molecular biologist . She is a Professor of Molecular Biology at Princeton University , where her laboratory studies molecular and genetic mechanisms in fruit fly Drosophila melanogaster oogenesis . Dr. Sch pbach was elected to the United States National Academy of Sciences National Academy of Sciences in 2005. She is married to Nobel laureate and fellow biologist Eric F. Wieschaus . External links http www.molbio.princeton.edu index.php?option content&task view&id 230 Princeton University faculty profile http www.molbio1.princeton.edu labs schupbach Sch pbach lab page Persondata Metadata see Wikipedia Persondata . NAME Schupbach, Gertrud ALTERNATIVE NAMES SHORT DESCRIPTION DATE OF BIRTH PLACE OF BIRTH DATE OF DEATH PLACE OF DEATH DEFAULTSORT Schupbach, Gertrud Category Swiss biologists Category Members of the United States National Academy of Sciences Category American biologists Category Geneticists Category Living people Category Year of birth missing living people biologist stub Switzerland scientist stub US biologist stub sl Gertrud Sch pbach ... more details
lowercase title vasa is an RNA binding protein with an RNA dependant helicase . The vasa gene, is essential for germ cell development and was first identified in Drosophila melanogaster . ref name Raz 2000 cite journal author Erez Raz title The function and regulation of vasa like genes in germ cell development journal Genome Biology volume 1 issue 3 pages reviews1017.1 reviews1017.6. year 2000 pmid 11178242 accessdate 2010 08 18 ref Expression In Drosophila , vasa expression is seen in germ cells, specifically the germline stem cells GSC s of female ovaries and in the early stages of spermatogensis in the male testis. Staining Due to the localization of vasa , immunohistochemistry staining can be done with vasa antibodies . For example, vasa antibody staining is specific for germline stem cells in the D. melanogaster germarium. Function Drosophila melanogaster In early embryogenesis, vasa is involved in abdomen development, Drosophila embryogenesis Maternal effect genes nanos mRNA translation, and pole plasm and germ cell formation. ref name Raz 2000 In oogenesis, vasa is involved in germline cyst development, oocyte differentiation, gurken mRNA translation, oocyte polarity and translation of oskar mRNA. ref name Raz 2000 References Reflist Category Developmental genes and proteins Category Genetics ... more details
Gametogenesis is a biology biological process by which diploid or haploid precursor cell s undergo cell division and differentiation to form mature haploid gamete s. Depending on the biological life cycle of the organism , gametogenesis occurs by meiosis meiotic division of diploid gametocyte s into various gametes, or by mitosis mitotic division of haploid gametogenous cells. For example, plants produce gametes through mitosis in gametophytes. The gametophytes grow from haploid spores after sporic meiosis. The existence of a multicellular, haploid phase in the life cycle between meiosis and gametogenesis is also referred to as alternation of generations . In animals Image Gray7.png thumb 400px Scheme showing analogies in the process of maturation of the ovum and the development of the spermatids, following their individual pathways. The oocytes and spermatocytes are both gametocytes. Ova and spermatids are complete gametes. In reality, the first polar body typically dies without dividing. Animals produce gametes directly through meiosis in organs called gonad s. Male s and female s of a species that sexual reproduction reproduces sexually have different forms of gametogenesis spermatogenesis male oogenesis female Stages However, before turning into gametogonia, the embryonic development of gametes is the same in males and females. Common path Gametogonia are usually seen as the initial stage of gametogenesis. However, gametogonia are themselves successors of primordial germ cells . During early embryonic development, primordial germ cells PGCs from the dorsal endoderm of the yolk sac migrate along the hindgut to the gonadal ridge . They multiply by mitosis and once they have reached the gonadal ridge in the late embryonic stage, they are called gametogonia. Gametogonia are no longer the same between males and females. Individual path From gametogonia, male and female gametes develop differently males by spermatogenesis and females by oogenesis. However, by conventi ... more details
, the germ cells undergo either spermatogenesis or oogenesis depending on whether the sex ... mature and functional spermatozoa . Oogenesis Main Oogenesis Mitotic germ stem cells, oogonia ... more details
Drugbox verifiedrevid 444347219 IUPAC name 1 5 nitro 1,3 thiazol 2 yl imidazolidin 2 one image Niridazole.png Clinical data tradename MedlinePlus a682128 pregnancy AU A B1 B2 B3 C D X pregnancy US A B C D X pregnancy category legal AU S2, S3, S4, S5, S6, S7, S8, S9 or Unscheduled legal CA Schedule I, II, III, IV, V, VI, VII, VIII legal UK GSL, P, POM, CD, or Class A, B, C legal US OTC Rx only Schedule I, II, III, IV, V legal status routes of administration Pharmacokinetic data bioavailability protein bound metabolism elimination half life excretion Identifiers CAS number 61 57 4 ATC prefix P02 ATC suffix BX02 PubChem 6093 DrugBank Ref drugbankcite correct drugbank DrugBank UNII Ref fdacite correct FDA UNII N116U8Y5QQ KEGG Ref keggcite correct kegg KEGG D05170 Chemical data chemical formula C 6 H 6 N 4 O 3 S 1 molecular weight 214.20 g mol Niridazole is a schistosomicide . ref cite pmid 6193406 ref It is used to treat schistosomiasis , the helmintic disease caused by certain flatworms trematode s from the genus Schistosoma formerly Bilharzia . It is also known by its trade name Ambilgar . It is usually is given as tablets. Niridazole has central nervous system toxicity and can cause dangerous side effects, such as hallucination s. Also, it may cause allergic reactions in sensitive people. However, it is one of the most effective schistosomicide drugs. It has recently also been investigated for use in the treatment of periodontitis . ref cite pmid 18027183 ref ref cite pmid 16877312 ref Mechanism of action Niridazole is rapidly concentrated in the parasite and inhibits oogenesis and spermatogenesis . The compound also inhibits the phosphofructokinase enzyme , leading to glycogen depletion and hepatic shift . References reflist Anthelmintics Category Antiparasitic agents Category Nitrothiazoles Category IARC Group 2B carcinogens Category Imidazolidinones Antiinfective drug stub ... more details
an oocyte through the process of oogenesis , and one daughter cell that is an identical oogonium to the parent ... oogenesis in which they enter meiosis . However, primary oocytes are arrested in prophase .... ref name repro bio Regulation of Oogonia Differentiation and Entry into Oogenesis The regulation and differentiation ... or differentiate into primary oocyte primary oocytes which enter oogenesis and are halted in prophase ... more details
is turned into a corpus luteum . Development of oocytes in ovarian follicles Main Oogenesis In a larger ... of meiosis I of ootidogenesis in oogenesis. The embryo nic development doesn t differ from .... ref Baker, T. G. 1982 . Oogenesis and ovulation. In Book 1 Germ cells and fertilization C. R ... more details
For the cells produced by plant roots that are also known as border cells, see root . The border cells of the fruit fly Drosophila melanogaster are a cluster of 6 8 migratory cell biology cell s found in the fly s ovary and derived from the follicular epithelium . Studying cell migration is important from the point of view of metastasis , and for this reason, several model organisms are used to determine what molecules are important in initiating, maintaining and guiding moving cells. Drosophila melanogaster is one of the favorite organisms for studying biological phenomena. The border cells of the Drosophila ovary are a genetically tractable system for studying diverse aspects of moving phenotype. After identifying the genes that are important for this phenotype , their homology biology homologs can be investigated for putative roles in turning non invasive cancerous tumors into metastatic ones. The egg chamber of the Drosophila ovary contains 16 central germline cells surrounded by a monolayer epithelium of about 1000 ovarian follicle follicle cells. At stage 9 of Drosophila oogenesis , these cells perform a stereotypical invasive migration on the intervening nurse cells, and reach the oocyte . The migration consists of an initial Posterior anatomy posterior migration, followed by another in the Dorsum biology dorsal direction. It is now known that the transcription factor Slbo slow border cells is a master regulator of the migratory phenotype, and the race is on to identify its targets. The migratory cluster is initiated by JAK STAT pathway and is guided by the growth of long cellular extensions. The directional cues are provided by receptor tyrosine kinase s. Cells that undergo such a change in fate as migratory border cells have two distinct alternatives reorganize the existing proteins or bring about massive changes in gene expression. In our case, the latter case seems to hold true. The transcription factor slbo which commandeers the transcription of several ... more details
italictitle Taxobox name Toxorhynchites image Toxorhynchites speciosus 01 L.D..jpg image caption Toxorhynchites speciosus image2 Toxorhynchites speciosus 03 L.D..jpg regnum Animal ia phylum Arthropod a classis Insect a ordo Fly Diptera familia Culicidae genus Toxorhynchites genus authority Frederick Vincent Theobald Theobald , 1901 subdivision ranks Species subdivision See text. Toxorhynchites , also known as mosquito hawk s or mosquito eaters , are a Cosmopolitan distribution cosmopolitan genus . The genus includes the largest known species of mosquitoes, but in spite of their alarming appearance, they are among the few kinds of mosquito that do not suck blood . Rather, the adults subsist on whatever carbohydrate rich materials might be available, such as honeydew , or saps and juices from damaged plants, Waste refuse , and fruit, but probably mainly nectar . The larva e of Toxorhynchites prey on the larvae of other mosquitoes and similar nekton ic prey. In this respect they contrast with blood sucking species of mosquitoes. Toxorhynchites larvae live on a protein and fat rich diet of aquatic animals such as mosquito larvae. They have no need to risk their lives sucking blood in adulthood, having already accumulated the necessary materials for oogenesis and vitellogenesis . Female mosquitoes whose larvae, unlike those of Toxorhynchites, are Detritivores detritus feeders could in principle subsist on nectar and the like, as their males in fact generally do. However, by relying on blood meals the females can produce eggs more plentifully than a diet of nectar would permit. Even though blood sucking is a risky strategy that entails more casualties, the risk is outweighed on average by the increase in the number and size of yolk rich eggs that such protein rich food permits. The name Toxorhynchites apparently comes from the Greek language Greek toxo meaning arrow and rhynch meaning snout . Most species occur in forest s. The larvae of one jungle variety, Toxorhynchites ... more details
Onesource date April 2009 Image Gray9.png thumb 300px First stages of segmentation of a mammalian embryo. Semidiagrammatic. z.p. Zona striata . p.gl. Polar bodies. a. Two cell stage. b. Four cell stage. c. Eight cell stage. d, e. Morula stage. A polar body is a cell biology cell structure found inside an ovum . Both animal and plant ova possess it. It is also known as a polar cell. Asymmetrical cell division cytokinesis leads to the production of polar bodies during oogenesis . To conserve nutrients, the majority of cytoplasm is segregated into the secondary oocyte during meiosis I, and the ovum during meiosis II. The remaining daughter cells generated from the meiotic events are small and contain relatively little cytoplasm and are referred to as polar bodies. Eventually, the polar bodies degenerate. There may be one or two polar bodies in the ovum. The first polar body is one of the two products in the first stage of meiosis and is considered haploid, with 23 chromosomes and 46 chromatids. The second polar body is also haploid, with 23 chromosomes and 23 chromatids. Sometimes the first polar body undergoes the second meiotic cell division. In flowering plant s, the pollen releases two male gametes sperm nuclei into the ovule upon fertilization . One fertilizes the haploid ovum and develops into a normal embryo, while the other fertilizes the two polar bodies within the center of the ovary, creating a structure called endosperm . Endosperm stores nutrients for initial growth of plant seed s. Cereal Cereal grain is an example of this, and is consumed for its nutritional value by many animals, including humans. Polar bodies are the by products of the egg s division during meiosis . As an egg matures, it goes through a two step division process, dividing once at the time when ovulation would occur and again at the time of fertilization. The three haploid polar bodies are the by products of this division, and are essentially discarded by the egg. By analyzing the polar ... more details
, respectively oogenesis and spermatogenesis is different for each species but the general stages are similar. Oogenesis and spermatogenesis have many features in common, they both involve Meiosis Extensive ... time while spermatogenic meiosis is rapid and uninterrupted. Oogenesis After migration primordial ... more details
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