“共轭聚合物-产电菌”复合生物电极构建及其在微生物燃料电池中的应用

微生物燃料电池(Microbial fuel cell,MFC)作为一种生物电化学装置,在可再生能源生产和废水处理方面的巨大潜力已引起广泛关注。然而MFC面临输出功率低、欧姆内阻高以及启动时间长等问题,极大限制了其在实际工程中的应用。MFC中阳极是微生物附着的载体,对电子的产生及传递起着关键作用,开发优质的生物电极已发展成为改善MFC性能的有效途径。共轭聚合物具有成本低、电导率高、化学稳定性及生物相容性好等优点,利用共轭聚合物修饰生物电极结构,可以实现大比表面积、缩短电荷转移路径,从而实现高效生物电化学性能。同时,纳米级共轭聚合物包覆细菌,可以使细菌产生的电子有效地传递到电极。文中综述了最近报道的共轭聚合物在MFC中的应用,重点介绍了共轭聚合物修饰的MFC阳极,系统分析了共轭聚合物的优点及局限性,以及这些高效复合生物电极如何解决MFC应用中存在的低输出功率、高欧姆内阻及长启动时间等问题。     

Strong Genetic Differentiation of Primula sikkimensis in the East Himalaya–Hengduan Mountains

The East Himalaya-Hengduan Mountains region is the center of diversity of the genus Primula, and P. sikkimensis is one of the most common members of the genus in the region. In this study, the genetic diversity and structure of P. sikkimensis populations in China were assessed using inter-simple sequence repeat (ISSR) and chloroplast microsatellite markers. The 254 individuals analyzed represented 13 populations. High levels of genetic diversity were revealed by ISSR markers. At the species level, the expected heterozygosity and Shannon’s index were 0.4032 and 0.5576, respectively. AMOVA analysis showed that 50.3% of the total genetic diversity was partitioned among populations. Three pairs of chloroplast microsatellite primers tested yielded a total of 12 size variants and 15 chloroplast haplotypes. Strong cpDNA genetic differentiation (G _ST = 0.697) and evidence for phylogeographic structure were detected (N _ST = 0.788, significantly higher than G _ST). Estimated rates of pollen-mediated gene flow are approximately 27% greater than estimated rates of seed-mediated gene flow in P. sikkimensis. Both seed and pollen dispersal, however, are limited, and gene flow among populations appears to be hindered by the patchiness of the species’ habitats and their geographic isolation. These features may have played important roles in shaping the genetic structure of P. sikkimensis. A minimum-spanning tree of chloroplast DNA haplotypes was constructed, and possible glacial refugia of P. sikkimensis were identified.     

小麦中期染色体银染蛋白的分析

对小麦中期染色体中银染蛋白的大小、形状和分布频率进行图像分析,看到：染色体顺的银染蛋白以颗粒状的形式存在,其大小不同,分布不均匀,数量差异也较大;从形状来看,大的银粒为点状,小的银粒有的为点状,有的实际为短纤维状,结果表明：染色体骨架在小麦中是真实存在的,骨架蛋白以颗粒和纤维状的形式分布于整个染色体中。     

物种多样性及环境因子对入侵植物空心莲子草群落稳定性的影响

为探讨外来入侵植物空心莲子草群落稳定性的驱动机制,在中国21°N-37°N范围内设置73个面积为10 mX 10 m的空心莲子草群落样地(陆生39个,水生34个),分别计算其Godron群落稳定性坐标值和4个α-物种多样性指数,并测定各样地的7项环境因子(经度、纬度、海拔、铵态氮、硝态氮、年均温和年均降雨量),采用回归...     

Identification of a 4-fluorobenzyl l-valinate amide benzoxaborole (AN11736) as a potential development candidate for the treatment of Animal African Trypanosomiasis (AAT)

Novel l-valinate amide benzoxaboroles and analogues were designed and synthesized for a structure-activity-relationship (SAR) investigation to optimize the growth inhibitory activity against Trypanosoma congolense (T. congolense) and Trypanosoma vivax (T. vivax) parasites. The study identified 4-fluorobenzyl (1-hydroxy-7-methyl-1,3-dihydrobenzo[c][1,2]oxaborole-6-carbonyl)-l-valinate (5, AN11736), which showed IC₅₀ values of 0.15?nM against T. congolense and 1.3?nM against T. vivax, and demonstrated 100% efficacy with a single dose of 10?mg/kg against both T. congolense and T. vivax in mouse models of infection (IP dosing) and in the target animal, cattle, dosed intramuscularly. AN11736 has been advanced to early development studies.     

Design and synthesis of highly selective pyruvate dehydrogenase complex E1 inhibitors as bactericides

In order to obtain PDHc-E1 inhibitors with high selectivity and efficacy, four series (7, 12, 15, and 19) of 35 novel 4-aminopyrimidine derivatives were rationally designed and synthesized based on the binding site of ThDP in E. coli PDHc-E1. 12, 15, and 19 were confirmed to be potent inhibitors against E. coli PDHc-E1. Selected compounds 12g, 12i, 15f, and 19a showed negligible inhibition against porcine PDHc-E1. To understand their selectivity, the interaction of inhibitor and E. coli PDHc-E1 or porcine PDHc-E1 was studied by molecular docking. The newly introduced acylhydrazone and N-phenylbenzamide moieties could form stronger interaction by hydrogen bond at the active site of E. coli PDHc-E1 compared with that of porcine PDHc-E1. A part of title compounds as potent PDHc-E1 inhibitors also exhibited notable antibacterial activity. In particular, 12e, 12f, 12g, 12o, and 19a exhibited 72–92% inhibition against Xanthomonas oryzae pv. Oryzae and Ralstonia solanacearum at 100?μg/mL, which was better than thiodiazole-copper (34 and 29%, respectively) and bismerthiazol (56 and 55%, respectively). The results proved that we could obtain effective bactericidal compounds as highly selective PDHc inhibitors by rational molecular design utilizing the binding model of active site of E. coli PDHc-E1.     

The salinity tolerance of the invasive golden apple snail (Pomacea canaliculata)

We exposed snails of an invasive species of golden apple snail (Pomacea canaliculata) to five artificial sea water treatments at salinity levels of 0, 5, 10, 15 or 20 parts per thousand (ppt) to assess their salinity tolerance. We observed the behaviour, heart rate, total haemocyte counts, haemolymph ionic concentration and Na⁺/K⁺-ATPase activity in the mantle at 0, 12, 24, 48, 72 and 96 h post salinity exposures. The heart rate declined with increasing salinity, while Na⁺/K⁺-ATPase activity in the mantle presented a reverse trend, possibly to maintain normal osmolality. A trend of rising total haemocyte count was observed from 0 ppt and 5 ppt to 10 ppt salinities, while a sudden increase in the count was observed at 15 ppt and 20 ppt salinity groups. Furthermore, haemolymph Cl^?, Na⁺ and K⁺ concentrations increased directly with elevated salinity. An additional trial was performed to assess the growth performance of the snails under exposure to low salinities. During a 1 month trial, snails grew better at 5 ppt salinity treatment. Taken together, our results demonstrate that P. canaliculata can tolerate salt stress to some extent. The finding also obviously implies a possible invasive risk to estuaries.     

Dynamic multiphoton imaging of acellular dermal matrix scaffolds seeded with mesenchymal stem cells in diabetic wound healing

Significantly effective therapies need to be developed for chronic nonhealing diabetic wounds. In this work, the topical transplantation of mesenchymal stem cell (MSC) seeded on an acellular dermal matrix (ADM) scaffold is proposed as a novel therapeutic strategy for diabetic cutaneous wound healing. GFP‐labeled MSCs were cocultured with an ADM scaffold that was decellularized from normal mouse skin. These cultures were subsequently transplanted as a whole into the full‐thickness cutaneous wound site in streptozotocin‐induced diabetic mice. Wounds treated with MSC‐ADM demonstrated an increased percentage of wound closure. The treatment of MSC‐ADM also greatly increased angiogenesis and rapidly completed the reepithelialization of newly formed skin on diabetic mice. More importantly, multiphoton microscopy was used for the intravital and dynamic monitoring of collagen type I (Col‐I) fibers synthesis via second harmonic generation imaging. The synthesis of Col‐I fibers during diabetic wound healing is of great significance for revealing wound repair mechanisms. In addition, the activity of GFP‐labeled MSCs during wound healing was simultaneously traced via two‐photon excitation fluorescence imaging. Our research offers a novel advanced nonlinear optical imaging method for monitoring the diabetic wound healing process while the ADM and MSCs interact in situ. Schematic of dynamic imaging of ADM scaffolds seeded with mesenchymal stem cells in diabetic wound healing using multiphoton microscopy. PMT, photo‐multiplier tube.      

Chitosan enhanced gene delivery of cationic liposome via non-covalent conjugation

Two new types of stable ternary complexes were formed by mixing chitosan with DOTAP/pDNA lipoplex and DOTAP with chitosan/pDNA polyplex via non-covalent conjugation for the efficient delivery of plasmid DNA. They were characterized by atomic force microscopy, gel retarding, and dynamic light scattering. The DOTAP/CTS/pDNA complexes were in compacted spheroids and irregular lump of larger aggregates in structure, while the short rod- and toroid-like and donut shapes were found in CTS/DOTAP/pDNA complexes. The transfection efficiency of the lipopolyplexes showed higher GFP gene expression than DOTAP/pDNA and CTS/pDNA controls in Hep-2 and Hela cells, and luciferase gene expression 2–3-fold than DOTAP/pDNA control and 70–120-fold than CTS/pDNA control in Hep-2 cells. The intracellular trafficking was examined by confocal laser scanning microscopy. Rapid pDNA delivery to the nucleus enchanced by chitosan was achieved after 4 h transfection.