Read Online The Spermatogenesis of Hydra: A Dissertation Submitted to the Faculty of the Ogden Graduate School of Science in Candidacy for the Degree of Doctor of Philosophy (Department of Botany) (Classic Reprint) - Elliot R Downing | PDF
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Gametogenesis in the Genus Hydra
The Spermatogenesis of Hydra: A Dissertation Submitted to the Faculty of the Ogden Graduate School of Science in Candidacy for the Degree of Doctor of Philosophy (Department of Botany) (Classic Reprint)
The Development of Hydra - JSTOR
THE DEVELOPMENT OF HYDRA - The University of Chicago Press
The spermatogenesis of Hydra ..: Amazon.com: Books
The spermatogenesis of Hydra .. : Downing, Elliot Rowland, b
Full text of The spermatogenesis of Hydra
The ultrastructural characteristics of spermatogenesis in Onchidium
Hydrozoa - The World Hydrozoa Database - Hydra oligactis Pallas
Hydra, a versatile model to study the homeostatic and
Spermatogenesis in anthozoa: Differentiation of the spermatid
The spermatogenesis of Hydra - CORE
Gametogenesis in the Genus Hydra Integrative and
Germinal differentiation of the stem cell in Hydra fusca: A
Hydra myc2, a unique pre-bilaterian member of the myc gene
The Spermatozoon of Actinia Equina L. Var. Mesembryanthemum
the REPRODUCTIVe system
Morphological description and characterization using a monoclonal antibody specific for cells of the spermatogenic.
Bosch (2001) role of epithelial cells and programmed cell death in hydra spermatogenesis.
Describe both sexual and asexual reproduction in hydra sexual- testes(6-8 in number) form from interstitial cells that produce a swelling in the upper third of the body.
Hydra undergoes two mutually exclusive modes of reproduction: at warm temperatures (18–22°c or 66-72f) they reproduce asexually by budding. How temperature controls the reciprocity of sexual and asexual reproduction.
Expression of hydra myc2 (a,b), cad (c,d), and myc1 (e,f) during spermatogenesis. (a,c) large clusters of early sperm precursor cells strongly expressing myc2 and cad are present in the upper body column of male polyps.
The cell proliferation and differentiation kinetics of intermediates in the spermatogenesis pathway were deter- mined, using quantitative determinations of cell abundance, pulse and continuous labelling with 3h-thymidine and nu- clear dna measurements.
Which of the following is true about hydra offspring produced by budding? it is identical to the parent hydra during spermatogenesis, a cell with 2n chromosomes divides to form four sperm cells.
6 jul 2007 we also suggest that late-stage spermatogenesis is the functional target for newly evolved and rapidly evolving male-specific genes.
Hydra oligactis undergo two mutually exclusive modes of reproduction: at warm temperatures (18–22°c) animals reproduce asexually by budding, while at cold temperatures (10–12°c) gamete differentiation occurs. Using a monoclonal antibody which is specific for cells of the sperm lineage, it was discovered that under conditions where sperm differentiation does not occur (18–22°c), cells continually enter the sperm pathway but progression down the pathway is prematurely halted.
Development of the spermatogonium involves an increase in nuclear and nucleolar size, and the formation of a dense mass of cytoplasmic ribosomes. The head consists of a bullet shaped, homogeneous nucleus, which lacks an acrosome but bears distal membrane specializations.
Lh stimulates the production of testosterone, which is necessary to continue the process of spermatogenesis. Testosterone is also important in the development of male characteristics, including muscle mass and strength, fat distribution, bone mass and sex drive.
Of sexual hydra is altered as compared to that of non-sexual in cross section, hydra is a two layered tube of cells enclos.
Spermatogenesis, suggesting that the hydra myc2 protein has a possible non-redundant function in cell cycle progression. The myc2 protein displays the principal design and properties of vertebrate myc proteins. In complex with max, myc2 binds to dna with similar affinity as myc1–max heterodimers.
7 sep 2015 there is a posterior nuclear fossa in the nucleus of the mature spermatozoon.
10 aug 2017 spermatogenesis dysfunctions may result in a qualitative and quantitative decrease of sperm output.
Morphological description and characterization using a monoclonal antibody specific for cells of the spermatogenic pathway.
A crucial role in the hydra holobiont and that hydra pro-vides an efficient, genetically tractable model system for the molecular dissection of these interactions. Localization and interaction of symbiotic algae and stably associated bacteria with hydra in the green species hydra viridis, the chlorella symbi-.
Hydra dioecia pelmatohydra oligactis (pallas, 1766) (synonym) the spermatogenesis of hydra.
This paper comments on the induction of gametogenesis, on microscopical and electronmicroscopical aspects of spermatogenesis and oogenesis and on fertilization in the genus hydra.
Many hydra can be are monoecious or hermaphrodite with o ne centrally located cell, the oocyte, which becomes larger and amoeboid with a large nucleus and yolk materials.
The first is bisexual reproduction, where a sperm not only triggers the egg for embryonic development but also contributes a haploid genome to the zygote. The zygote develops eventually into a male or female adult in which germ cells undergo meiosis and produce haploid gametes for the new generation.
The hydra produces buds; starfish can regenerate an entire body from a fragment of the original body. Asexual reproduction allows an organism to rapidly produce many offspring without the time and resources committed to courtship, finding a mate, and mating.
This mitosis occurs within the nuclear area but not inside the nuclear membrane. Centrioles are present and appear to be enclosed within the nuclear membrane during the early telephase. Various fixing agents have great effect upon the chromosomes, causing them to shrink from their v-shape to rather rod-like structures.
During spermatogenesis, germ cells of hydra viridis are in a closed compartment.
9 oct 2007 it has been proposed that inactivation of the x chromosome during spermatogenesis contributes to these patterns: genes with a beneficial.
Species of hydra, the spermatogenesis of three species of hydra has been studied. In undertaking to discover which species these were, a tangle of terminology has been encountered. Nussbaum, 1887 (70) after care- fully reviewing the literature on the various species of hydra con- cludes that all the forms described can be included under four species: viridis, grisea, fusca, and attenuata.
(e,f) myc1 expression is detectable neither in early stages of spermatogenesis, nor in mature testes.
And electronmicroscopical aspects of spermatogenesis and oogenesis and living hydras start producing gametes.
Ultrastructural and cytochemical aspects of spermiogenesis in hydra hymanae, with reference to factors involved in sperm head shaping.
Melanogaster hydra is expressed most intensely in the proximal testis, suggesting a role in late-stage spermatogenesis. The coding region of hydra has a relatively high ka/ks ratio between species, but the ratio is less than 1 in all comparisons, suggesting that hydra is subject to functional constraint.
The testis forms by evagination of the ectodermal epithelia layer in the upper half of the body column. Spermatogenesis occurs in the space created by this evagination.
(2004) mili, a mammalian member of piwi family gene, is essential for spermatogenesis.
In the basal metazoan hydra spermatogenesis takes place in anatomically simple testes and in the absence of accessory structures. Hydra sperm precursors are derived from interstitial stem cells.
Publication date 1905 topics hydra, spermatogenesis publisher chicago collection americana.
An organism undergoes a series of changes throughout its life cycle. Gametogenesis (spermatogenesis and oogenesis), plays a crucial role in humans to support the continuance of generations. Gametogenesis is the process of division of diploid cells to produce new haploid cells.
Parthenogenesis (/ ˌ p ɑːr θ ɪ n oʊ ˈ dʒ ɛ n ɪ s ɪ s,-θ ɪ n ə-/; from the greek παρθένος, parthénos, 'virgin' + γένεσις, génesis, 'creation') is a natural form of asexual reproduction in which growth and development of embryos occur without fertilization by sperm.
Different species of hydra are either dioecious or hermaphroditic. Testes form from interstitial cells that produce a swelling in the upper third of the body. In the ovary, a large, yolk-filled oocyte forms in a manner similar to the testes.
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