检索结果-南通市图书馆

Pheromone 3kPZS evokes context-dependent serotonin sexual dimorphism in the brain of the sea lamprey (Petromyzon marinus)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2015年第1期10卷 91-101页

作者： Yuwen CHUNG-DAVIDSON Huiyong WANG anne MSCOTT Weiming LI Department of Fisheries and Wildlife Michigan State UniversityEast LansingMIUSA

Mature male sea lampreys(Petromyzon marinus)release a sex pheromone,3-keto-petromyzonol sulfate(3kPZS),that induces sexually dimorphic behavioral responses in ***,the neural mechanism of such responses is mostly *** examined the neurotransmitter serotonin(5-hydroxytryptamine,5-HT)and the expression of 5-HT1A receptors in the forebrain and brainstem of sea lamprey exposed to the vehicle(0.91 ppm methanol)or 10−10 M 3kPZS for 2 h using high performance liquid chromatography-electrospray ionization tandem mass spectrometry,immunohistochemistry and real-time quantitative polymerase chain *** to 3kPZS for 2 h increased 5-HT concentration in the forebrain of adult females,whereas 5-HT was not detected in the forebrain of adult *** the contrary,3kPZS exposure decreased 5-HT concentration in the brainstem of adult females and had no effect in adult *** exposure evoked context-dependent sexual dimorphism in brain 5-HT1A receptor immunoreactivity,but had no effect on 5-HT1A mRNA concentrations in the brain with 2 h exposure *** appears that in sea lamprey pheromone 3kPZS affects the 5-HT system in the brain in a context-dependent,sexually dimorphic manner.

关键词： 5-HT1A receptor liquid chromatography-electrospray ionization tandem mass spectrometry motor output real-time quantitative polymerase chain reaction

Phosphorus mobility in dam reservoir affected by redox oscillations:An experimental study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2019年第3期31卷 250-263页

作者： anne Rapin Malgorzata Grybos Marion Rabiet Brice Mourier Véronique Deluchat Université de Limoges PEIRENE EA 7500 Faculté des Sciences et Techniques Université de Lyon UMR5023 Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés Université Lyon 1ENTPE CNRS

The internal sedimentary phosphorus(P) load of aquatic systems is able to support eutrophication, especially in dam–reservoir systems where sedimentary P stock is high and where temporary anaerobic conditions occur. The aim of this study therefore is to examine the response of sedimentary P exposed to redox oscillations. Surface sediments collected in the Champsanglard dam–reservoir(on the Creuse River, France) were subjected to two aerobic phases(10 and 12 days) alternated with two anaerobic periods(21 and 27 days)through batch incubations. The studied sediment contained 77 ± 3 μmol/g DW of P, mainly associated with the ascorbate fraction(amorphous Fe/Mn oxyhydroxides). The used sediment was rich in organic matter(OM)(21% ± 1%) with primarily allochthone *** results showed that redox oscillations enhance dissolved inorganic phosphorus release at sediment/water interface. During the first anaerobic stage, the P release was mainly controlled by the dissolution/precipitation of iron minerals. The more pronounced increase of P release during the second anaerobic stage(44%) was due to various mechanisms related to the change in quality of dissolved organic matter(DOM), namely a higher SUVA254 and humification indices. The release of more refractory DOM(rDOM) served to lower the microbial metabolism activity, possibly favored iron oxyhydroxide aggregation and thus limiting iron reduction. In addition, rDOM is able to compete for mineral P sorption sites,leading to a greater P release. In reservoir with predominant allochthone OM input, the release of more aromatic DOM therefore plays an important role in P mobility.

关键词： Phosphorus Sediment Redox Iron Organic matter

The role of hypogonadism in Klinefelter Syndrome

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2014年第2期16卷 185-191,I0007页

作者： Christian Host anne Skakkeb k Kristian A Groth Anders Bojesen Departments of Pediatrics Endocrinology and Internal Medicine (MEA) Molecular Medicine Cardiology Aarhus University Hospital Aarhus Department of Clinical Genetics Vejle Hospital Vejlep Institute of Regional Health Research University of Southern Denmark Odense Denmark.

Klinefelter syndrome （KS）（47, XXY） is the most abundant sex-chromosome disorder, and is a common cause of infertility and hypogonadism in men. Most men with KS go through life without knowing the diagnosis, as only 25% are diagnosed and only a few of these before puberty. Apart from hypogonadism and azoospermia, most men with KS suffer from some degree of learning disability and may have various kinds of psychiatric problems. The effects of long-term hypogonadism may be difficult to discern from the gene dose effect of the extra X-chromosome. Whatever the cause, alterations in body composition, with more fat and less muscle mass and diminished bone mineral mass, as well as increased risk of metabolic consequences, such as type 2 diabetes and the metabolic syndrome are all common in KS. These findings should be a concern as they are not simply laboratory findings; epidemiological studies in KS populations show an increased risk of beth hospitalization and death from various diseases. Testosterone treatment should be offered to KS patients from early puberty, to secure a proper masculine development, nonetheless the evidence is weak or nonexisting, since no randomized controlled trials have ever been published. Here, we will review the current knowledge of hypogonadism in KS and the rationale for testosterone treatment and try to give our best recommendations for surveillance of this rather common, but often ignored, syndrome.

关键词： androgen receptor body composition bone density hypogonadism infertility Klinefelter syndrome learning disorders male testosterone

Biosynthesis of Callose and Cellulose by Detergent Extracts of Tobacco Cell Membranes and Quantification of the Polymers Synthesized in vitro

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2010年第2期52卷 221-233页

作者： Carolina Cifuentes Vincent Bulone anne Mie C.Emons Laboratory of Plant Cell Biology Wageningen University Division of Glycoscience School of BiotechnologyRoyal Institute of TechnologyAlbaNova University Center Department of Biomolecular Systems FOM Institute for Atomic and Molecular Physics

The conditions that favor the in vitro synthesis of cellulose from tobacco BY-2 cell extracts were determined. The procedure leading to the highest yield of cellulose consisted of incubating digitonin extracts of membranes from 11-day-old tobacco BY-2 cells in the presence of 1 mM UDP-glucose, 8 mM Ca^2＋ and 8 mM Mg^2＋. Under these conditions, up to nearly 40% of the polysaccharides synthesized in vitro corresponded to cellulose, the other polymer synthesized being callose. Transmission electron microscopy analysis revealed the occurrence of two types of structures in the synthetic reactions. The first type consisted of small aggregates with a diameter between 3 and 5 nm that associated to form fibrillar strings of a maximum length of 400 nm. These structures were sensitive to the acetic/nitric acid treatment of Updegraff and corresponded to callose. The second type of structures was resistant to the Updegraff reagent and corresponded to straight cellulose microfibrils of 2-3 nm in diameter and 200 nm to up to 5 μm in length. In vitro reactions performed on electron microscopy grids indicated that the minimal rate of microfibril elongation in vitro is 120 nm/min. Measurements of retardance by liquid crystal polarization microscopy as a function of time showed that small groups of microfibrils increased in retardance by up to 0.047 nm/min per pixel, confirming the formation of organized structures.

关键词： Biosynthesis of Callose and Cellulose by Detergent Extracts of Tobacco Cell Membranes and Quantification of the Polymers Synthesized in vitro

Androgenic regulation of novel genes in the epididymis

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2007年第4期9卷 545-553页

作者： Bernard Robaire Shayesta Seenundun Mahsa Hamzeh Sophie-anne Lamour Department of Pharmacology and Therapeutics McGill University Montrgal QC H3G1Y6 Canada Department of Obstetrics and Gynecology McGill University Montrgal QC H3G1Y6 Canada

The epididymis is critically dependent on the presence of the testis. Although several hormones, such as retinoids and progestins, and factors secreted directly into the epididymal lumen, such as androgen binding protein and fibroblast growth factor, might play regulatory roles in epididymal function, testosterone （T） and its metabolites, dihydrotestosterone （DHT） and estradiol （E2）, are accepted as the primary regulators of epididymal structure and functions, with the former playing the greater role. To ascertain the molecular action of androgens on the epididymis, three complementary approaches were pursued to monitor changes in gene expression in response to different hormonal milieux. The first was to establish changes in gene expression along the epididymis as androgenic support is withdrawn. The second was to determine the sequence of responses that occur in an androgen deprived tissue upon re-administration of the two metabolites of T, DHT and E2. The third was to study the effects of androgen withdrawal and re-administration on gene expression in immortalized murine caput epididymidal principal cells. Specific responses were observed under each of these conditions, with an expected major difference in the panoply of genes expressed upon hormone withdrawal and re-administration; however, some key common features were the common roles of genes in insulin like growth factor/epidermal growth factor and the relatively minor and specific effects of E2 as compared to DHT. Together, these results provide novel insights into the mechanisms of androgen regulation in epididymal principal cells. （Asian J Androl 2007 July; 9： 545-553）

关键词： epididymis cell culture androgen withdrawal dihydrotestosterone estradiol apoptosis survivin insulin like growth factor

Seasonal and habitat dependence of fleas parasitic on small mammals in Tanzania

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2009年第2期4卷 196-212页

作者： anne LAUDISOIT Herwig LEIRS Rhodes MAKUNDI Boris Ronald KRASNOV Zoogeographical Research Unit Universitéde LiègeLiègeBelgium Evolutionary Ecology Group Universiteit AntwerpenAntwerpenBelgium General bacteriology Unit VARBrusselsBelgium Danish Pest Infestation Laboratory Department of Integrated Pest ManagementUniversity of AarhusKongens LyngbyDenmark Pest Management Centre Sokoine University of AgricultureMorogoroTanzania Mitrani Department of Desert Ecology Jacob Blaustein Institute for Desert ResearchBen-Gurion University of the NegevMidreshet Ben-GurionIsrael

We investigated host and flea species composition across different habitats during dry and rainy seasons in the Western Usambara Mountains in *** both seasons,similarity in flea species composition increased with an increase in the similarity in host species ***,between-season within-habitat as well as within-season between-habitat similarity in host species composition was higher than similarity in flea species *** of habitats according to their host and flea species composition demonstrated that the pattern of between-habitat similarity in both host and flea species composition varied *** the relatively rich mammal and flea fauna of the study region,the major contribution to variation in species composition between seasons and among habitats was due to a few species *** assemblages on Lophuromys kilonzoi Verheyen et al.,2007 and Praomys delectorum Thomas,1910 in different habitats were equally similar in either *** contrast,flea assemblages on Mastomys natalensis(Smith,1834)occurring in different habitats were more similar in the dry than in the rainy season,whereas the opposite was the case for fleas on Grammomys *** different hosts,the main differences in species composition of flea assemblages between seasons as well as among habitats were due to different flea *** our results support the earlier idea that parasite species composition is determined by both host species composition and habitat properties,the former appears to explain variance in flea species composition between localities in the tropics better than between localities in temperate and arid zones.

关键词： Africa flea assemblages rodents seasonal tropical habitats.

A Novel Two Domain-Fusion Protein in Cyanobacteria with Similarity to the CAB/ELIP/HLIP Superfamily： Evolutionary Implications and Regulation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2008年第1期1卷 155-166页

作者： Oliver Kilian anne Soisig Steunou Arthur R. Grossman Devaki Bhaya Department of Plant Biology The Carnegie Institution Stanford CA 94305 USA

Vascular plants contain abundant, light-harvesting complexes in the thylakoid membrane that are non-covalently associated with chlorophylls and carotenoids. These light-harvesting chlorophyll a/b binding （LHC） proteins are members of an extended CAB/ELIP/HLIP superfamily of distantly related polypeptides, which have between one and four transmembrane helices （TMH）. This superfamUy includes the single TMH, high-light-inducible proteins （Hlips）, found in cyanobacteria that are induced by various stress conditions, including high light, and are considered ancestral to the LHC proteins. The roles of, and evolutionary relationships between, these superfamily members are of particular interest, since they function in both light harvesting and photoprotection and may have evolved through tandem gene duplication and fusion events. We have investigated the Hlips （hli gene family） in the thermophilic unicellular cyanobacterium Synechococcus OS-B＇. The five hli genes present on the genome of Synechococcus OS-B＂ are relatively similar, but transcript analyses indicate that there are different patterns of transcript accumulation when the cells are exposed to various growth conditions, suggesting that different Hlips may have specific functions. Hlip5 has an additional TMH at the N-terminus as a result of a novel fusion event. This additional TMH is very similar to a conserved hypothetical, single membrane-spanning polypeptide present in most cyanobacteria. The evolutionary significance of these results is discussed.

关键词： light-harvesting chlorophyll a/b binding (LHC) transmembrane helices (TMH) high-light-inducible proteins (Hlips)

Laboratory and field testing of bolting systems subjected to highly corrosive environments

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2017年第1期27卷 101-106页

作者： Meikle Tom Tadolini Stephen C. Sainsbury Bre-anne Bolton John Minova Richmond Vale NSW 2327Australia Minova Georgetown KY 43204USA Mining and Resource Engineering Monash University VIC 3800 CaulfieldAustralia

The capacity of ground support components which have been affected by corrosion is reduced and may ultimately lead to dynamic failure of the component and the strata. In order to maintain an effective,long-term ground support system, significant campaigns of rehabilitation are often required in corrosion affected areas which also expose the workers to hazardous conditions. The most common corrosion protection for steel ground support utilises sacrificial systems such as galvanising. Galvanising has previously been proven to be susceptible to some corrosion processes. Stainless steel is the most effective in resistance to corrosion, but can be cost prohibitive, and its mechanical properties often make it unsuited to use in ground support components. Providing an outer protective plastic coating to bolts has proven to be an effective means of protecting the inner steel bar from corrosion. However, these support systems tend to be susceptible to coating damage, and require post cement grouting to provide full encapsulation. In comparison to a standard bolt/resin system, they can be slow to install and *** systems have also been shown to reduce overall load transfer performance of the bolting system. In order to provide a higher level of corrosion protection whilst maintaining current installation practices and bolting cycle times, Minova has developed the Enduro^(TM)steel ground support range. The Enduro^(TM) range consists of standard Minova steel ground support components which have been treated with a unique coating process. The Enduro^(TM)coating has been tested in the harshest of conditions, in laboratory controlled conditions and in underground trials. It has been proven to effectively resist or completely eliminate the formation of corrosion, even in the most aggressive environments. This paper explains the process and provides the details of the laboratory and underground corrosion performance testing carried out on Enduro^(TM)ground support product

关键词： Corrosion Coatings Galvanised Salt spray Accelerated corrosion testing

In vitro immunotoxicity of untreated and treated urbanwastewaters using various treatment processes to rainbow trout leucocytes

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2013年第7期25卷 1400-1407页

作者： Franois Gagné Marlène Fortier Michel Fournier Shirley-anne Smyth Emerging Methods Aquatic Contaminants Research Division Water Science and Technology Environment Canada105 McGill Street Montral Qubec Canada INRS-Institut Armand-Frappier 531 boul.des Prairies Laval Qubec Canada Effluents and Wastewaters Aquatic Contaminants Research Division Water Science and Technology Environment Canada867 Lakeshore Road BurlingtonOntario Canada

Municipal effluents are known to impede the immune system of aquatic organisms. The purpose of this studywas to examine the immunotoxicity of urbanwastewaters before and after 6 treatment processes from 12 cities toward trout leucocytes. Freshly prepared trout leucocyteswere exposed to increasing concentrations of solid phase （C18） extracts ofwastewaters for24 hr at 15°C. Immunocompetencewasdetermined by following changes in leucocyte viability and the proportion of cells able to ingest at least one （immunoactivity） and at least three （immunoefficiency） fluorescent beads. The influentswere treated by sixdifferent treatment strategies consisting of facultative aerated lagoons, activated sludge, biological aerated filter, biological nutrient removal, chemically-assisted physical treatment and trickling filter/solid contact. Water quality parameters of thewastewaters revealed that the plants effectively removed total suspended solids and reduced the chemical oxygendemand. The results revealed that the effluents＇ immunotoxic propertieswere generally more influenced by the properties of the untreatedwastewaters than by the treatment processes. About half of the incoming influentsdecreased leucocyte viabilitywhile4 treatment plantswere able to reduce toxicity. The influents readily increased phagocytosis activity for 8/12 influentswhile itwasdecreased in4/12 influents. This increasewas abolished for4/12 of the effluents using treatments involving biological and oxidative processes. In conclusion, municipal effluents have the potential to alter the immune system in fish and more researchwill be needed to improve the treatments ofwastewaters to better protect the quality of the aquatic environment.

关键词： municipal effluents fish leucocytes viability phagocytosis