Aspidistra anomala,A. elegans and A. sinensis spp. nov. (Asparagaceae,Convallariaceae s.s.) from China,Laos and Vietnam

The recently discovered Aspidistra anomala, A. elegans, and A. sinensis are described and illustrated as species new to science. All novelties are local endemics of limestone areas of mainland southeast Asia.     

The refined 2.3 A crystal structure of human leukocyte elastase in a complex with a valine chloromethyl ketone inhibitor

The stoichiometric complex formed between human leukocyte elastase and a synthetic MeO-Suc-Ala-Ala-Pro-Val chloromethyl ketone inhibitor was co-crystallized and its X-ray structure determined, using Patterson search methods. Its structure has been crystallographically refined to a final R value of 0.145 (8.0 and 2.3 A). The enzyme structure is very similar to that recently observed in a complex formed with the ovomucoid third domain from turkey [(1986) EMBO J. 5,2453-2458]. The rms deviation of all alpha-carbon atoms is 0.32 A. The peptidic inhibitor is bound in a similar overall conformation as the ovomucoid binding segment. Covalent bonds are formed between Val-P1 of the inhibitor and His-57 NE2 and Ser-195 OG of the enzyme. The carbonyl carbon is tetrahedrally deformed to a hemiketal. The valine side chain is arranged in the S1 pocket in the g-conformation.     

水稻雄配子体发育过程中tRNA片段的生物信息学分析

tRNA片段(tRF)是tRNA通过非随机剪切产生的RNA片段, 其产生和功能机制尚不明确; 而在水稻(Oryza sativa)雄配子体发育过程中, 人们对tRNA更是知之甚少。通过高通量测序, 在水稻雄配子体发育过程中发现了长度范围较大的tRFs; 进一步采用logo对tRFs两端的序列进行分析, 发现了4个有序列特征(其中3个未见报道)和1个无序列特征的酶切位点; 通过NCBI Blast预测了tRF靶基因, 发现其大多靶向转座因子。研究结果对揭示tRF产生机制以及水稻雄配子体发育研究有一定的参考价值。     

Parasites may exit immunocompromised northern pig-tailed macaques(Macaca leonina) infected with SIVmac239

Parasites can increase infection rates and pathogenicity in immunocompromised human immunodeficiency virus(HIV) patients. However, in vitro studies and epidemiological investigations also suggest that parasites might escape immunocompromised hosts during HIV infection.Due to the lack of direct evidence from animal experiments, the effects of parasitic infections on immunocompromised hosts remain unclear. Here,we detected 14 different parasites in six northern pig-tailed macaques(NPMs) before or at the 50 th week of simian immunodeficiency virus(SIV) infection by ELISA. The NPMs all carried parasites before viral injection. At the 50 th week after viral injection, the individuals with negative results in parasitic detection(i.e., 08247 and 08287) were characterized as the Parasites Exit(PE) group, with the other individuals(i.e., 09203, 09211, 10205, and 10225) characterized as the Parasites Remain(PR) group. Compared with the PR group, the NPMs in the PE group showed higher viral loads, lower CD4~+T cells counts, and lower CD4/CD8 rates. Additionally, the PE group had higher immune activation and immune exhaustion of both CD4~+and CD8~+T cells. Pathological observation showed greater injury to the liver, cecum, colon,spleen, and mesenteric lymph nodes in the PE group.This study showed more seriously compromised immunity in the PE group, strongly indicating that parasites might exit an immunocompromised host.     

Efficient Passivation of Hybrid Perovskite Solar Cells Using Organic Dyes with COOH Functional Group

Organic–inorganic halide perovskites are efficient absorbers for solar cells. Nevertheless, the trap states at the surfaces and grain boundaries are a detrimental factor compromising the device performance. Here, an organic dye (AQ310) is employed as passivator to reduce the trap states of the perovskites and promote better stability. The results demonstrate that the trap states of perovskite are minimized by the presence of AQ310's ?COOH group and the formation of coordination with under‐coordinated Pb²⁺ ions. The resulting carrier recombination time is prolonged and verified by the photoluminescence and open‐circuit voltage decay measurements. Consequently, the best average power conversion efficiency (PCE) of 19.43% is achieved for the perovskite solar cell (PSC) with AQ310 passivation, as compared with a low average PCE of 17.98% for the PSC without AQ310 passivation.