Expression of aquaporin 9 in rat liver and efferent ducts of the male reproductive system after neonatal diethylstilbestrol exposure.

Aquaporins (AQP) have important solute transport functions in many tissues including the epididymal efferent ducts (ED) and in the liver. We investigated the effect of neonatal exposure to diethylstilbestrol (DES) on AQP9 expressions in the ED and in the liver of rats. DES was administered from day 2 to day 20 postnatally at a dose of 4,8 microg/day, and AQP9 protein and mRNA were measured by immunoblotting and real-time PCR, respectively, along with immunohistochemistry. DES caused hepatic downregulation of AQP9 at both the protein and mRNA level; however, decreased AQP9 labeling was only observed in the periportal zone. In the ED, AQP9 protein expression was increased in the DES-treated animals by 300% that could be ascribed to a widening of the ED lumen, whereas no difference was observed in AQP9 mRNA expression. Immunohistochemical findings revealed that AQP9 expression was confined to the epithelial cells of the ED. In conclusion, neonatal DES exposure appears to upregulate AQP9 channels in the ED in male rats, whereas a downregulation in the hepatic expression was observed, particularly in the periacinous area.     

Efferent ductules of the fan-throated lizard Sitana ponticeriana Cuvier: light and transmission electron microscopy study

Light microscopy histology of efferent ductules and the ultrastructural organization of their epithelium were studied in the fan‐throated lizard Sitana ponticeriana Cuvier. The ductules of this lizard are extra‐testicular and arise from an extra‐testicular rete testis. A major portion of the ductules is intra‐epididymal and occupies the cephalic end of the epididymis. The ductules differentiate histologically into proximal and distal portions. The epithelium is formed of two major tall columnar cell types, the non‐ciliated and ciliated, and one minor cell type, the basal cells. Dark cells were also identified. The non‐ciliated cells possess microvilli towards the luminal end, tubular coated pits at the bases of the microvilli, coated vesicles in the apical cytoplasm and multivesicular bodies, lysosomes and mitochondria in the supranuclear and perinuclear cytoplasm, which reflects their role in the uptake of the material they are processing. These cells also participate in spermiophagy. The ciliated cells reflect their role in mixing the luminal content and/or its transport to the distal parts of the male tract. The lizard efferent ductules share many features in common with those of mammals and a crocodile and several other features with birds and a turtle. Spermiophagy by the efferent ductules is reported here for the first time in a reptile.     

Regulation of cell adhesion in the Drosophila embryo by phosphorylation of the Cadherin-Catenin-Complex

Cell-culture studies indicate that tyrosine phosphorylation of the cadherin-catenin-complex (CCC) is one of the post-translational mechanism regulating E-cadherin-mediated cell adhesion. In this investigation, controlled application of a tyrosine phosphatase inhibitor (orthovanadate) and tyrosine kinase inhibitor (tyrphostin) to early Drosophila embryos, followed by biochemical assays and phenotypic analysis, has been utilized to address the mechanism by which tyrosine phosphorylation regulates E-cadherin-mediated cell adhesion in vivo. Our data suggest that, in the Drosophila embryo, β-catenin (Drosophila homolog Armadillo) is the primary tyrosine-phosphorylated protein in the CCC. The increase in tyrosine phosphorylation correlates with a loss of epithelial integrity and adherens junctions in the ectoderm of early embryos. Late application of the phosphatase inhibitor does not have this effect, presumably because of the formation of septate junctions in late embryos. Co-immunoprecipitation assays have demonstrated that tyrosine hyper-phosphorylation does not cause the dissociation of Drosophila (D)E-cadherin and α-catenin or Armadillo, suggesting that abrogation in adhesion is most likely attributable to the detachment of actin-associated proteins from the CCC. Finally, although the Drosophila epidermal growth factor receptor (EGFR), a receptor tyrosine kinase, is linked to the CCC and shows genetic interactions with DE-cadherin, we find that a constitutively active Drosophila EGFR construct does not cause any detectable changes in the level of tyrosine phosphorylation of Armadillo or destabilization of the CCC. This work was supported by UCLA USPHS National Research Service Award GM07185 to F.W., and NIH Grant NS 29367 to V.H.     

鳖油的制备及其理化性质研究

利用传统炮制方法制备了鳖油 ,其得率为 5 8.31% ,并测定了其含量、酸价及皂化值等理化数据。其中多不饱和脂肪酸质量分数为 42 .47% ,GC分析结果二十碳五烯酸及二十二碳六烯酸烯质量分数分别为 14.82 %、19.10 %。     

Predicted distributions and abundances of the sea turtle ‘lost years’ in the western North Atlantic Ocean

Oceanic dispersal characterizes the early juvenile life-stages of numerous marine species of conservation concern. This early stage may be a ‘critical period’ for many species, playing an overriding role in population dynamics. Often, relatively little information is available on their distribution during this period, limiting the effectiveness of efforts to understand environmental and anthropogenic impacts on these species. Here we present a simple model to predict annual variation in the distribution and abundance of oceanic-stage juvenile sea turtles based on species’ reproductive output, movement and mortality. We simulated dispersal of 25 cohorts (1993–2017) of oceanic-stage juveniles by tracking the movements of virtual hatchling sea turtles released in a hindcast ocean circulation model. We then used estimates of annual hatchling production from Kemp's ridley Lepidochelys kempii (n = 3), green Chelonia mydas (n = 8) and loggerhead Caretta caretta (n = 5) nesting areas in the northwestern Atlantic (inclusive of the Gulf of Mexico, Caribbean Sea and eastern seaboard of the U.S.) and their stage-specific mortality rates to weight dispersal predictions. The model's predictions indicate spatial heterogeneity in turtle distribution across their marine range, identify locations of increasing turtle abundance (notably along the U.S. coast), and provide valuable context for temporal variation in the stranding of young sea turtles across the Gulf of Mexico. Further effort to collect demographic, distribution and behavioral data that refine, complement and extend the utility of this modeling approach for sea turtles and other dispersive marine taxa is warranted. Finally, generating these spatially-explicit predictions of turtle abundance required extensive international collaboration among scientists; our findings indicate that continued conservation of these sea turtle populations and the management of the numerous anthropogenic activities that operate in the northwestern Atlantic Ocean will require similar international coordination.     

A genetic survey of heavily exploited, endangered turtles: caveats on the conservation value of trade animals

Asian turtles face an extinction crisis, and so it is imperative that systematists accurately determine species diversity in order to guide conservation strategies effectively. We surveyed mitochondrial and nuclear DNA (mtDNA and nuDNA) variation of the heavily exploited Mauremys mutica complex, a clade of Asian turtles that contains the endangered M. mutica from Japan, Taiwan, China and Vietnam, and the critically endangered Mauremys annamensis from central Vietnam. We discovered extensive mtDNA and nuDNA variation among samples that did not correspond to the currently recognized taxonomy. Both nuDNA and mtDNA data suggest that M. mutica is paraphyletic with respect to M. annamensis . Surprisingly, M. annamensis exhibits a previously unknown mtDNA structure in the form of two clades that are paraphyletic to M. mutica . These data reveal that the currently recognized taxonomy of the mutica complex does not reflect the genetic diversity of our samples. Unfortunately, many conservation-oriented captive-breeding efforts for turtles are also based on trade samples such as the ones studied here. These efforts include plans to breed trade-rescued individuals and release their progeny into the wild. Because our genetic survey reveals that the taxonomic identity of these samples does not reflect genetic diversity, we raise serious questions about the efficacy of these programs. In order to address conservation issues and provide more accurate estimates of evolutionary lineages within Mauremys , we recommend continued surveys for wild populations of the mutica complex to provide new genetic material and additional distributional data, attempts to extract DNA from historic museum specimens and a shift in conservation focus to in situ preservation of wild populations and associated habitat.