澳门鸟类资源调查报告

1989～2009年在澳门山林和沿海滩涂湿地对鸟类进行了调查和记录,共记录鸟类297种,加上文献中记录的3种,整理出澳门鸟类名录共300种,隶属17目56科.其中非雀形目有30科160种,占澳门鸟类总种数的53.33%;雀形目有26科140种,占澳门鸟类种数46.67%.就数量来看,澳门鸟类中的优势种有9种,常见种44种,偶见种96种,稀有种则有151种.白腹海雕Haliaeetus leucogaster属于国家Ⅰ级重点保护野生鸟类.属于国家Ⅱ级重点保护的鸟类有33种.澳门鸟类属于<濒危野生动植物种国际贸易公约,2007>公约附录Ⅰ的有游隼Falco peregrinus peregrinus、小青脚鹬Tringa guttifer和小杓鹬Numenius minutus 3种,属于公约附录Ⅱ的有29种.勺嘴鹬Eurynorhynchus pygmeus被世界自然保护联盟(2009)列入极危(CR)鸟类,黑脸琵鹭Platalea minor和小青脚鹬被列入濒危(EN)鸟类.易危(VU)鸟类有4种,近危(NT)鸟类有5种.本文成果可为今后长期监测和保护澳门鸟类资源提供依据.     

Interaction of the ring finger-related U-box motif of a nuclear dot protein with ubiquitin-conjugating enzymes

The U-box domain has been suggested to be a modified RING finger motif where the metal-coordinating cysteines and histidines have been replaced with other amino acids. Known U-box-containing proteins have been implicated in the ubiquitin/proteasome system. In a search for proteins interacting with the ubiquitin-conjugating enzyme UbcM4/UbcH7, we have identified a novel U-box containing protein, termed UIP5, that is exclusively found in the nucleus as part of a nuclear dot-like structure. Interaction between UbcM4 and UIP5 was observed in vivo and in vitro with bacterially expressed proteins. In addition to UbcM4, several other ubiquitin-conjugating enzymes (E2s) that share the same sequence within the L1 loop bind to UIP5. Mutational analysis showed that the U-box, like the RING finger in other proteins, forms the physical basis for the interaction with E2 enzymes. Further support for the structural similarity between U-box and RING finger comes from the observation that, in both cases, the same regions within the UbcM4 molecule are required for interaction. Our results establish at the molecular level a link between the U-box and the ubiquitin conjugating system and strongly suggest that proteins containing U-box domains are functionally closely related to RING finger proteins.     

Trophic state and nutrient limitation in Lake Baringo,Kenya

The trophic state of Lake Baringo and factors that could be limiting the development of algal biomass in it were investigated during one wet/dry hydrological cycle in 2014–2015. Water samples were analysed for dissolved inorganic nutrients, including , and , total phosphorus and Chlorophyll a. Light attenuation was estimated using Secchi depth. The trophic state was determined using Carlson trophic state indices (CTSI). Deviations in CTSI, nutrient ratios and ambient nutrient concentrations were used to identify factors limiting phytoplankton growth. The mean values measured for Secchi depth, nitrate, total phosphorus and Chlorophyll a showed significant seasonal variation (p < 0.05). Based on the Carlson trophic state index, the results show that Lake Baringo is eutrophic. However, the lake is also experiencing phosphorus limitation and poor light penetration, because of high turbidity, which is more pronounced during the wet season.     

Fc gamma receptor IIB on dendritic cells enforces peripheral tolerance by inhibiting effector T cell responses

The uptake of immune complexes by FcRs on APCs augments humoral and cellular responses to exogenous Ag. In this study, CD11c+ dendritic cells are shown to be responsible in vivo for immune complex-triggered priming of T cells. We examine the consequence of Ab-mediated uptake of self Ag by dendritic cells in the rat insulin promoter-membrane OVA model and identify a role for the inhibitory FcgammaRIIB in the maintenance of peripheral CD8 T cell tolerance. Effector differentiation of diabetogenic OT-I CD8+ T cells is enhanced in rat insulin promoter-membrane OVA mice lacking FcgammaRIIB, resulting in a high incidence of diabetes. FcgammaRIIB-mediated inhibition of CD8 T cell priming results from suppression of both DC activation and cross-presentation through activating FcgammaRs. Further FcgammaRIIB on DCs inhibited the induction of OVA-specific Th1 effectors, limiting Th1-type differentiation and memory T cell accumulation. In these MHC II-restricted responses, the presence of FcgammaRIIB only modestly affected initial CD4 T cell proliferative responses, suggesting that FcgammaRIIB limited effector cell differentiation primarily by inhibiting DC activation. Thus, FcgammaRIIB can contribute to peripheral tolerance maintenance by inhibiting DC activation alone or by also limiting processing of exogenously acquired Ag.     

Small angle X-ray scattering of intact and lysing cell nuclei

X-ray scattering at very low angles has been applied to the study of chromatin structure in intact and lying nuclei. From maxima and minima in the very low angle range, higher order or very large structures could be deduced, the existence of which has not been found in isolated chromatin; up to now, such structures could be demonstrated only be electron-micrographs of whole nuclei. A strong maximum at 0.12 nm^?1 or a shoulder at 0.08 nm^?1 is interpreted as a hollow or solid cylinder with diameter ～ 70 nm; however, another possible explanation, a side by side packing of 30 nm solenoids^1–4 with a distance of 52 nm, cannot be excluded. A shoulder at 0.033 nm^?1 leads to the conclusion that an even larger structure exist in interphase nuclei. A slight minimum at 0.2 nm^?1 is in the range where mildly isolated chromatin has its first order minimum. This accounts for a coil diameter ～ 30 nm. While in intact nuclei these characteristics of the scattering curve have only a low intensity (except the maximum at 0.12 nm^?1 lysing nuclei exhibit much more pronounced maxima.     

Low angle X-ray scattering studies of chromatin in different solvents; analysis by comparison with computer-simulated scattering curves

Low-angle X-ray scattering curves of isolated calf thymus chromatin, dissolved in 0.2 mm EDTA, 0.2 mm MgCl₂ or 0.5 m NaCl, have been analysed by comparison with simulated scattering curves of models from chromatin subunits and higher order structure. The results provided additional data based on established models. Assuming the protein core as a cylinder of 5.9–6.0 nm diameter and 5.9-2.0 nm height, the centre to centre distance of the cores in tightly packed chromatin was found to be 6.7 nm. Computer simulation of X-ray scattering of chromatin was fitted to experimentally derived data for estimating the ratios of quaternary and tertiary structure. Slight differences of the quaternary structures of 0.15 m NaCl adn in 0.2 mm MgCl₂ were observed.