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221.
Pei-Ying Feng G. S. de Hoog M. J. Najafzadeh A. H. G. Gerrits van den Ende J. B. Stielow H. Badali W. A. Boeger V. A. Vicente 《Mycological Progress》2014,13(2):381-391
A novel species of Cladophialophora is described from the natural environment of the mangrove land crab (Ucides cordatus) along the coast, and from plant sources in Brazil. It is morphologically very similar to Cladophialophora bantiana, though with moderately melanized conidia produced in strongly coherent and poorly branched chains which arise directly from undifferentiated hyphae, but deviates unambiguously on the basis of molecular phylogeny. The species has a maximum growth temperature of 36 °C and seems to be a strict saprobe. 相似文献
222.
In the androdioecious nematode Caenorhabditis elegans, self-fertilization is the predominant mode of reproduction. Nevertheless, males do occur, and it is still unclear if these represent a selective advantage or merely an evolutionary relict. In this study, we first tested the hypothesis that the production of males might benefit invaders to resident populations. We added single, GFP-marked worms to established laboratory populations and followed GFP frequencies over time. Mated hermaphrodites and also males were more successful in invading resident populations if compared to single, unmated hermaphrodites. The observed higher frequencies should increase the likelihood that any of the associated invading alleles persist. Second, we tested the hypothesis that males and, thus, higher outcrossing rates, are specifically favored under changing environmental conditions. After an outbred population was subjected to changing stress or to control laboratory conditions, we measured the male maintenance of the resulting populations. Interestingly all populations, experimental and control alike, showed high male maintenance, suggesting that persistence of males is also favored under standard laboratory conditions. 相似文献
223.
Hyporesponsiveness to glucocorticoids in mice genetically deficient for the corticosteroid binding globulin
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Petersen HH Andreassen TK Breiderhoff T Bräsen JH Schulz H Gross V Gröne HJ Nykjaer A Willnow TE 《Molecular and cellular biology》2006,26(19):7236-7245
Corticosteroid binding globulin (CBG) is the carrier for glucocorticoids in plasma. The protein is believed to keep the steroids inactive and to regulate the amount of free hormone acting on target tissues (free hormone hypothesis). Here, we generated a mouse model genetically deficient for CBG to test the contribution of the carrier to glucocorticoid action and adrenocortical stress response. The absence of CBG resulted in a lack of corticosterone binding activity in serum and in an approximately 10-fold increase in free corticosterone levels in CBG-null mice, consistent with its role in regulation of circulating free hormone levels. Surprisingly, cbg(-/-) animals did not exhibit features seen in organisms with enhanced glucocorticoid signaling. Rather, the mice exhibited increased activity of the pituitary axis of hormonal control, normal levels of gluconeogenetic enzymes, and fatigue, as well as an aggravated response to septic shock, indicating an inability to appropriately respond to the excess free corticosterone in the absence of CBG. Thus, our data suggest an active role for CBG in bioavailability, local delivery, and/or cellular signal transduction of glucocorticoids that extends beyond a function as a mere cargo transporter. 相似文献
224.
Schulenburg H Kurtz J Moret Y Siva-Jothy MT 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2009,364(1513):3-14
An organism's fitness is critically reliant on its immune system to provide protection against parasites and pathogens. The structure of even simple immune systems is surprisingly complex and clearly will have been moulded by the organism's ecology. The aim of this review and the theme issue is to examine the role of different ecological factors on the evolution of immunity. Here, we will provide a general framework of the field by contextualizing the main ecological factors, including interactions with parasites, other types of biotic as well as abiotic interactions, intraspecific selective constraints (life-history trade-offs, sexual selection) and population genetic processes. We then elaborate the resulting immunological consequences such as the diversity of defence mechanisms (e.g. avoidance behaviour, resistance, tolerance), redundancy and protection against immunopathology, life-history integration of the immune response and shared immunity within a community (e.g. social immunity and microbiota-mediated protection). Our review summarizes the concepts of current importance and directs the reader to promising future research avenues that will deepen our understanding of the defence against parasites and pathogens. 相似文献
225.
Aetheolabes goeldiensis n. g., n. sp. (Diplectanidae) is described from the gills of ‘pescada’ Plagioscion sp. (Sciaenidae) collected from the Baía de Marajó, about 30 km north of Belém, Pará, Brazil. The monotypic Aetheolabes n. g. is characterised, in part, by its type-species having the haptor and haptoral sclerites modified as a clasp for attachment
to the gill tissue of its host, the copulatory complex situated far posterior to the intestinal bifurcation near the mid-length
of the trunk, the vaginal pore apparently within the genital atrium, the tegument lacking scales, anchors atypical for diplectanids,
and by lacking peduncular spines and squamodiscs. A. goeldiensis n. sp. closely resembles Diplectanum umbrinum Tripathi, 1957 from India and China by the haptoral sclerites forming a clasp, but differs from it primarily by the orientation
of the reproductive organs and absence of squamodiscs. 相似文献
226.
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228.
Christina Claussen Jana Madlen Knapp Martina Kapitza Andrea Bernholt Hinrich Schulenburg Kerstin Kremer 《当今生物学》2020,50(4):270-277
The Darwin Day: modern science meets school During the Darwin Day at the University of Kiel high school students are introduced to recent research fields in modern biology. In 2018 the holistic view of a metaorganism offered the students new scientific ways of thinking and working, which are important for a profound understanding of biological interrelations as well as current clinical disorders. In order to bring new insights from biological research and modern science to school, different formats of science communication can be used. One possibility is the visit of extracurricular learning opportunities such as the Darwin Day at the University of Kiel. By linking current biological research with an out-of-school learning place, the importance of science communication can be illustrated. For this purpose, the Darwin Day and an accompanying teaching unit are presented in this article. Furthermore, insights into the evaluation of this outreach format are given. 相似文献
229.
Thomas Hübener Sven Adler Petra Werner Manuela Schult Helmut Erlenkeuser Hinrich Meyer Mandy Bahnwart 《Hydrobiologia》2009,631(1):303-327
This study aims to identify reference conditions (nutrient status and diatom assemblages) as required by the European Water
Framework Directive (WFD) for stratified, carbonate-rich lowland lakes with a large watershed area (watershed area to lake
volume ratio (WV) > 1.5 km2 10−6 m−3) and a retention time (RT) from 0.1 to 10 years (Central Baltic Lake-Type 1, German Lake-Type 10) in European ecoregion 14.
Diatoms, pollen and geochemistry were analysed from sediment cores of six lakes from northern Germany representing different
subtypes of Lake-Type 10 (varying WV and RT) and covering the past 290–1,750 years. Historic total phosphorus levels were
inferred using diatom-based transfer functions selected from a merged European data set and from optimised data sets identified
with the moving-window approach. Pollen and geochemical proxies were used to identify occurrence and intensity of anthropogenic
catchment usage. Lake trophic state reference conditions and associated diatom assemblages were identified for three of the
six study lakes. In contrast, according to fossil pollen assemblages, two lakes were already strongly impacted by intensive
catchment usage when the oldest investigated sediments were laid down. Thus, reference conditions of these already eutrophic
lakes could not be identified. Similarly, the lowermost samples of a core from the sixth lake showed signs of impact, and
it remains unclear whether the identified dystrophic conditions occurred naturally or if they were due to the drainage of
wetlands in Medieval times. Lakes with a relatively small WV (1.5–5.0 km2 10−6 m−3) and RT > 1 year were naturally oligotrophic to low mesotrophic and a typical, representative diatom assemblage was identified.
In contrast, typical reference conditions or diatom assemblages for lakes with higher WV (5–18.6 km2 10−6 m−3) and RT < 1 year could not be identified as chemical precipitation and upstream lakes (nutrient sinks or sources) additionally
influenced natural nutrient levels. Therefore, the reference situation of both trophic state and diatom assemblages in a lake
may be strongly influenced by other modifying, limnological processes in addition to WV and RT. Overall, this study helps
to implement the WFD by identifying reference conditions and by discussing the level of differentiation of lake types required
to set reference conditions.
Guest editors: K. Buczkó, J. Korponai, J. Padisák & S. W. Starratt
Palaeolimnological Proxies as Tools of Environmental Reconstruction in Fresh Water 相似文献
230.
J E Luettges A Boeger S Nitschke-Dabelstein U Pudlo G Zwiens H Prinz 《Journal of reproduction and fertility》1985,74(2):371-376
The histopathological lesions remaining after microsurgical tubal reanastomosis were investigated quantitatively by light microscopy and qualitatively by transmission and scanning electron microscopy. In 23 rabbit oviducts, the influence of the suture material poly-p-dioxanon and polyglactin-910 and post-operative time interval (6 and 12-15 weeks) was evaluated and compared with non-anastomosed contralateral oviducts as well as with those of unoperated controls. Except in the controls, partial deciliation, pathological kinocilia structure, microvilli and cytoplasmic blebs were found in all tissues, demonstrating an almost complete endosalpingeal restoration. A statistically significant increase of the muscular thickness was observed on the operated and unoperated sides and was due to fibrosis and expressed by cell/stroma ratio. Subepithelial microgland-like structures also appeared on both sides. As neither the kind of suture material nor time intervals led to differences in tissue reaction and, moreover, as similar alterations were found in the non-anastomosed oviducts, the lesions are presumed to be mainly the response to laparotomy. 相似文献