Follicle Stimulating Hormone, Luteinizing Hormone and Testicular Leydig Cell Responses to Estradiol Immunization in Ile-de-France Rams

Active immunization of Ile-de-France rams against estradiol (E2) resulted in the production of E2-neutralizing antibodies and an elevation in the plasma concentrations of FSH, LH, and testosterone. The presence of E2 antibodies did not affect the testosterone metabolic clearance rate, indicating that the immunization-mediated 10-fold increase in plasma testosterone was the result of a 10-fold increase in testicular testosterone production. Testis weights, as well as nuclear and cytoplasmic volumes of individual peritubular and perivascular Leydig cells, were greater in E2-immunized rams than in albuminimmunized controls. Leydig cell numbers were not affected by treatment. The E2 antibodies were capable not only of neutralizing the inhibitory effects of endogenous E2 on gonadotropin levels in intact rams, but were able to block the effects of exogenously administered E2 on their FSH and Lii secretory response to castration. It is concluded that circulating E2 in the ram is involved in pituitary-testicular endocrine homeostasis and that E2 immunoneutralization can be employed to enhance testosterone secretion in this species

Sertoli cell proliferation during the post hatching period in domestic fowl

There has been no study aimed at directly determining of the periods of Sertoli cell proliferation in birds even domestic fowl. The aims of this study were to observe the cessation of post-hatching mitotic proliferation of Sertoli cells in domestic fowl, and to determine the volume density of Sertoli and germ cells during this period. A total of 50 Leghorn chicks were used in this study. The testes sections of the animals were immunostained with BrdU to observe the proliferation of cells from one to 10 weeks of age. The volume density of the Sertoli and germ cells were determined using the standard point counting method. The volume density of the germ cell nuclei was initially less than that of the Sertoli cells but the volume density converged by week 6, and remained relatively constant until the commencement of meiosis. Clear labeling of Sertoli and germ cells was observed from week 1 to week 7. The only those cells still labeled after 8 weeks were germ cells, indicating that Sertoli cell proliferation had ceased. Therefore, it is recommended that any research into the testes of domestic fowl should consider the cessation of Sertoli cell proliferation by approximately 8 weeks

Some considerations for analyzing biodiversity using integrative metagenomics and gene networks

<p>Abstract</p> <p>Background</p> <p>Improving knowledge of biodiversity will benefit conservation biology, enhance bioremediation studies, and could lead to new medical treatments. However there is no standard approach to estimate and to compare the diversity of different environments, or to study its past, and possibly, future evolution.</p> <p>Presentation of the hypothesis</p> <p>We argue that there are two conditions for significant progress in the identification and quantification of biodiversity. First, integrative metagenomic studies - aiming at the simultaneous examination (or even better at the integration) of observations about the elements, functions and evolutionary processes captured by the massive sequencing of multiple markers - should be preferred over DNA barcoding projects and over metagenomic projects based on a single marker. Second, such metagenomic data should be studied with novel inclusive network-based approaches, designed to draw inferences both on the many units and on the many processes present in the environments.</p> <p>Testing the hypothesis</p> <p>We reached these conclusions through a comparison of the theoretical foundations of two molecular approaches seeking to assess biodiversity: metagenomics (mostly used on prokaryotes and protists) and DNA barcoding (mostly used on multicellular eukaryotes), and by pragmatic considerations of the issues caused by the 'species problem' in biodiversity studies.</p> <p>Implications of the hypothesis</p> <p>Evolutionary gene networks reduce the risk of producing biodiversity estimates with limited explanatory power, biased either by unequal rates of LGT, or difficult to interpret due to (practical) problems caused by type I and type II grey zones. Moreover, these networks would easily accommodate additional (meta)transcriptomic and (meta)proteomic data.</p> <p>Reviewers</p> <p>This article was reviewed by Pr. William Martin, Dr. David Williams (nominated by Pr. J Peter Gogarten) & Dr. James McInerney (nominated by Pr. John Logsdon).</p

Evolutionary history of the Corallinales (Corallinophycidae, Rhodophyta) inferred from nuclear, plastidial and mitochondrial genomes

Systematics of the red algal order Corallinales has a long and convoluted history. In the present study, molecular approaches were used to assess the phylogenetic relationships based on the analyses of two datasets: a large dataset of SSU sequences including mainly sequences from GenBank; and a combined dataset including four molecular markers (two nuclear: SSU, LSU; one plastidial: psbA; and one mito- chondrial: COI). Phylogenetic analyses of both datasets re-affirmed the monophyly of the Corallinales as well as the two families (Corallinaceae and Hapalidiaceae) currently recognized within the order. Three of the four subfamilies of the Corallinaceae (Corallinoideae, Lithophylloideae, Metagoniolithoideae) were also resolved as a monophyletic lineage whereas members of the Mastophoroideae were resolved as four distinct lineages. We therefore propose to restrict the Mastophoroideae to the genera Mastophora, Metamastophora, and possibly Lithoporella in the aim of rendering this subfamily monophyletic. In addition, our phylogenies resolved the genus Hydrolithon in two unrelated lineages, one containing the gener- itype Hydrolithon reinboldii and the second containing Hydrolithon onkodes, which used to be the generitype of the now defunct genus Porolithon. We therefore propose to resurrect the genus Porolithon for the second lineage encompassing those species with primarily monomerous thalli, and trichocyte arrangements in large pustulate horizontal rows. Moreover, our phylogenetic analyses revealed the presence of cryptic diversity in several taxa, shedding light on the need for further studies to better circumscribe species frontiers within the diverse order Corallinales, especially in the genera Mesophyllum and Neogoniolithon.Web of Scienc

Шероховатость поверхностей при финишной алмазно-абразивной обработке

Показано, что шероховатость полированной поверхности зависит от отношения частот собственных колебаний молекулярных фрагментов на поверхностях инструмента и обрабатываемой детали. На шероховатость обработанной поверхности наибольшее влияние оказывают число молекулярных фрагментов, из которых состоят частицы шлама, их наиболее вероятный размер, частоты собственных колебаний фрагментов обрабатываемого материала и инструмента, теплопроводность обрабатываемого материала и режимы обработки

Juvenile morphology of the large Antarctic canopy-forming brown alga, Desmarestia menziesii J. Agardh

Open Access via Springer Compact Agreement. We are grateful to the UK Natural Environment Research Council for funding to FCK (grants NE/D521522/1 and NE/J023094/1), in particular through the Collaborative Antarctic Science Scheme (Grant CASS-134, 2017) to FCK and LSP. Funding for cruise-based observations in 2019 was from US National Science Foundation award OPP-1744550 to CDA. We thank Kate Stanton, Teresa Murphy and Ben Robinson (British Antarctic Survey) for support with diving operations around Rothera in January–February 2018, and also Richard L. Moe (UC Berkeley) for locating specimens corresponding to the morphology described here in the UC collection. Special thanks are due to Charlie Bibby (Financial Times) for taking professional photographs of the unknown Desmarestia sp. in the aquarium of the Bonner Lab at Rothera (Fig. 2a). We would also like to thank Richard L. Moe (UC Berkeley) and Christian Wiencke (AWI Bremerhaven) for their very helpful reviews of this paper. Also, the MASTS pooling initiative (Marine Alliance for Science and Technology for Scotland, funded by the Scottish Funding Council and contributing institutions; grant reference HR09011) is gratefully acknowledged for supporting FCK. This research contributes to the SCAR Ant-ERA research programme.Peer reviewedPublisher PD

Essais d'embouche du Zébu Malgache

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