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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Fish physiology and biochemistry 17 (1997), S. 143-153 
    ISSN: 1573-5168
    Keywords: goldfish ; activin ; inhibin ; receptors ; perifusion ; immunocytochemistry ; cloning ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Activin (βAβA, βAβB and βBβB) is a dimeric protein that belongs to the transforming growth factor-β (TGF-β) superfamily of growth factors and is involved in the regulation of many physiological and developmental processes. Recently, we have demonstrated that porcine activin stimulated goldfish gonadotropin-II (GTH-II) and growth hormone (GH) secretion from dispersed pituitary cells in static culture and pituitary fragments in perifusion. The action of activin in the goldfish is unique in that it has an acute stimulatory effect on the secretion of GTH-II and GH, whereas in mammals activin usually exhibits long-term stimulatory actions on FSH secretion. The action mechanism of activin is different from that of gonadotropin-releasing hormone (GnRH). Using domain-specific antibodies against mammalian activin subunits, we subsequently demonstrated the existence of immunoreactive activin subunits (βA and βB) in the goldfish ovary, testis, pituitary and brain, suggesting endocrine, paracrine and autocrine roles for activin in the regulation of goldfish reproduction. Both activin βA and βB subunits have been cloned from goldfish genome by polymerase chain reaction (PCR). Using the PCR fragments as probes, we have cloned a full length cDNA coding for activin βB subunit from the goldfish ovary. Both activin βA and βB subunits show high homology to those of other vertebrates with the βB subunit much more conserved (93 and 98% identity with human and zebrafish βB subunit, respectively). The identity of the cloned βB subunit was further confirmed by expression in the Chinese hamster ovary (CHO) cells and detection of the specific activity of activin in the culture medium. The messenger RNA of activin βB subunit is expressed in a variety of goldfish tissues including ovary, testis, brain, pituitary, kidney and liver, suggesting a wide range of physiological roles for activin in the goldfish. We have also cloned a full length cDNA coding for the activin Type IIB receptor from the goldfish ovary, suggesting that activin may have paracrine or autocrine actions on the ovarian functions. The identity of the cloned receptor was confirmed by specific binding of125 I-activin on COS-1 cells transfected with the cloned Type IIB receptor.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 36 (2000), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The lipopolysaccharides (LPS) of most Helicobacter pylori strains contain complex carbohydrates known as Lewis antigens that are structurally related to the human blood group antigens. Investigations on the genetic determinants involved in the biosynthesis of Lewis antigens have led to the identification of the fucosyltransferases of H. pylori, which have substrate specificities distinct from the mammalian fucosyltransferases. Compared with its human host, H. pylori utilizes a different pathway to synthesize the difucosylated Lewis antigens, Lewis y and Lewis b. Unique features in the H. pylori fucosyltransferase genes, including homopolymeric tracts mediating slipped-strand mispairing and the elements regulating translational frameshifting, enable H. pylori to produce variable LPS epitopes on its surface. These new findings have provided us with a basis to further examine the roles of molecular mimicry and phase variation of H. pylori Lewis antigen expression in both persistent infection and pathogenesis of this important human gastric pathogen.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Meteorology and atmospheric physics 63 (1997), S. 131-148 
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary The paper concerns the sensitivity of the regional mesoscale model (MM4) to a moisture transport algorithm with different accuracies, and the effective improvement of the capability to simulate meso-scale synoptical event by using the revised version of the algorithm. The two advective schemes of second-order moment conservational Prather scheme (PRS hereinafter) and the polynomial-fitted fourth-order Bott scheme and the upstream scheme (UPS) are introduced into the MM4 to calculate moisture transport in order to provide other types of the algorithm with different accuracies for choice in addition to the original B grid second-order central scheme. Of the three schemes, the first two ensure the positive definite character with high accuracy (almost no numerical disspation and computational dispersion); and the last one also keeps the positive definite feature, but possesses stronger capability of numerical dissipation. Case studies have been undertaken of several rainstorm and typhoon events by virtue of the different-accuracy moisture transport algorithm, other things being the same. Results reveal great differences between them. An significant improvement is found in determining meso-scale synoptic system structure, rain cluster activity, rainstorm belt and its center, severity and its persistence, and the false alarm of or failure to report subrainstorm center when the PRS scheme is employed. Obviously, these differences and improvement are only due to moisture re-distribution for different schemes of moisture transport and the related variation of latent heat. The paper investigates the influences of different numerical schemes. The high accuracy and positive solution PRS application which produces a significant improvement in the model result, demonstrating the sensitivity of the model to moisture distribution in the model represents an important measure to improve the simulation by means of revising the numerically calculating method.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2024-04-22
    Description: The Global Consortium for the Classification of Fungi and fungus-like taxa is an international initiative of more than 550 mycologists to develop an electronic structure for the classification of these organisms. The members of the Consortium originate from 55 countries/regions worldwide, from a wide range of disciplines, and include senior, mid-career and early-career mycologists and plant pathologists. The Consortium will publish a biannual update of the Outline of Fungi and funguslike taxa, to act as an international scheme for other scientists. Notes on all newly published taxa at or above the level of species will be prepared and published online on the Outline of Fungi website (https://www.outlineoffungi.org/), and these will be finally published in the biannual edition of the Outline of Fungi and fungus-like taxa. Comments on recent important taxonomic opinions on controversial topics will be included in the biannual outline. For example, ‘to promote a more stable taxonomy in Fusarium given the divergences over its generic delimitation’, or ‘are there too many genera in the Boletales?’ and even more importantly, ‘what should be done with the tremendously diverse ‘dark fungal taxa?’ There are undeniable differences in mycologists’ perceptions and opinions regarding species classification as well as the establishment of new species. Given the pluralistic nature of fungal taxonomy and its implications for species concepts and the nature of species, this consortium aims to provide a platform to better refine and stabilise fungal classification, taking into consideration views from different parties. In the future, a confidential voting system will be set up to gauge the opinions of all mycologists in the Consortium on important topics. The results of such surveys will be presented to the International Commission on the Taxonomy of Fungi (ICTF) and the Nomenclature Committee for Fungi (NCF) with opinions and percentages of votes for and against. Criticisms based on scientific evidence with regards to nomenclature, classifications, and taxonomic concepts will be welcomed, and any recommendations on specific taxonomic issues will also be encouraged; however, we will encourage professionally and ethically responsible criticisms of others’ work. This biannual ongoing project will provide an outlet for advances in various topics of fungal classification, nomenclature, and taxonomic concepts and lead to a community-agreed classification scheme for the fungi and fungus-like taxa. Interested parties should contact the lead author if they would like to be involved in future outlines.
    Keywords: Plant Science ; Ecology ; Evolution ; Behavior and Systematics
    Repository Name: National Museum of Natural History, Netherlands
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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  • 9
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    PANGAEA
    In:  Supplement to: Zhang, Yi Ge; Zhang, Chuanlun L; Liu, Xiao-Lei; Li, Li; Hinrichs, Kai-Uwe; Noakes, T D (2011): Methane Index: A tetraether archaeal lipid biomarker indicator for detecting the instability of marine gas hydrates. Earth and Planetary Science Letters, 307(3-4), 525-534, https://doi.org/10.1016/j.epsl.2011.05.031
    Publication Date: 2023-05-12
    Description: Gas hydrates represent one of the largest pools of readily exchangeable carbon on Earth's surface. Releases of the greenhouse gas methane from hydrates are proposed to be responsible for climate change at numerous events in geological history. Many of these inferred events, however, were based on carbonate carbon isotopes which are susceptible to diagenetic alterations. Here we propose a molecular fossil proxy, i.e., the "Methane Index (MI)", to detect and document the destabilization and dissociation of marine gas hydrates. MI consists of the relative distribution of glycerol dibiphytanyl glycerol tetraethers (GDGTs), the core membrane lipids of archaea. The rational behind MI is that in hydrate-impacted environments, the pool of archaeal tetraether lipids is dominated by GDGT-1, -2 and -3 due to the large contribution of signals from the methanotrophic archaeal community. Our study in the Gulf of Mexico cold-seep sediments demonstrates a correlation between MI and the compound-specific carbon isotope of GDGTs, which is strong evidence supporting the MI-methane consumption relationship. Preliminary applications of MI in a number of hydrate-impacted and/or methane-rich environments show diagnostic MI values, corroborating the idea that MI may serve as a robust indicator for hydrate dissociation that is useful for studies of global carbon cycling and paleoclimate change.
    Type: Dataset
    Format: application/zip, 4 datasets
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  • 10
    facet.materialart.
    Unknown
    PANGAEA
    In:  Supplement to: Meng, Fanbao; Baud, Patrick; Ge, Hongkui; Wong, Teng-fong (2019): The Effect of Stress on Limestone Permeability and Effective Stress Behavior of Damaged Samples. Journal of Geophysical Research: Solid Earth, 124(1), 376-399, https://doi.org/10.1029/2018JB016526
    Publication Date: 2023-01-13
    Description: The evolution of permeability and its effective stress behavior is related to inelastic deformation and failure mode. This was systematically investigated in Indiana and Purbeck limestones with porosities of 16% and 14%, respectively. High‐pressure compression tests were conducted at room temperature on water‐saturated samples. At relatively high confinement shear‐enhanced compaction was observed to initiate at a critical stress, accompanied by significant permeability reduction of up to a factor of ~3. Overall, the permeability reduction due to inelastic compaction in our limestones is smaller than that observed in sandstones. At relatively low confinement, dilatant failure was observed, which was accompanied by a decrease and increase of permeability in Indiana and Purbeck limestones, respectively. There seems to be a trend for the correlation between porosity and permeability changes to switch from positive to negative with increasing porosity. The void space of both limestones has significant proportions of macropores and micropores. The effective stress behavior of such a limestone with dual porosity has been documented to be different from the prediction for a microscopically homogeneous assemblage, in that its effective stress coefficients for permeability and pore volume change may attain values significantly 〉1. In contrast, our investigation of damaged samples consistently showed effective stress coefficients for both permeability and pore volume change with values 〈1. This suggests that the behavior in the damaged samples is akin to that of a microscopically homogeneous assemblage, possibly due to pervasive collapse of macropores that would effectively homogenize the initially bimodal pore size distribution.
    Type: Dataset
    Format: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, 5.4 MBytes
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