中国南方喀斯特荔波世界自然遗产地翼手目物种多样性与保护现状

为了解荔波世界自然遗产地翼手目动物的物种多样性和生存现状, 作者于2010年10月至2011年10月, 对中国南方喀斯特荔波世界自然遗产地区域内6个镇(乡)69个洞穴的翼手目动物进行了考察, 发现60个洞穴有翼手目动物栖息痕迹, 其中可以确定具体栖息物种的洞穴有37个。本次调查观察记录到翼手目动物10万余只, 隶属5科15种, 结合文献记载及贵州师范大学动物标本室保存的翼手目动物标本, 确认该地区共有翼手目动物7科24种。11种翼手目动物在荔波世界自然遗产地为首次记录, 其中狭耳鼠耳蝠(Myotis blythii)、果树蹄蝠(Hipposideros pomona)2种为贵州省翼手目新记录。该地区一些洞穴已被开发为旅游景点, 严重影响了洞穴内翼手目动物的生存, 翼手目动物保护状况令人担忧, 建议对翼手目动物栖息的洞穴采取必要的保护措施。     

Association of matrix metalloproteinases-9 gene polymorphisms with genetic susceptibility to esophageal squamous cell carcinoma

Matrix metalloproteinases-9 (MMP-9) plays important roles in tumor invasion and metastasis by degrading extracellular matrix components. Variations in the DNA sequence in the MMP-9 gene may lead to altered MMP-9 production and/or activity, and so this may modulate an individual's susceptibility to esophageal squamous cell carcinoma (ESCC). To test this hypothesis, we investigated the association of the MMP-9 polymorphisms and their haplotypes with the risk of ESCC in a Chinese population. There were significant differences in the genotype and allele distribution of P574R polymorphism of the MMP-9 gene among cases and controls. The P574R GG genotypes were associated with a significantly increased risk of ESCC as compared with the CC genotypes (odds ratio [OR] = 4.08; 95% confidence interval [CI]: 1.58-10.52; p = 0.00). Compared with 279R-574P haplotype, 279R-574R (OR = 3.52; 95% CI: 1.99-6.25) and 279Q-574P (OR = 2.16; 95% CI: 1.07-4.35) haplotypes can increase the onset risk of ESCC statistically, but the role of 279R-574R haplotype is more obvious. MMP-9 P574R polymorphisms and P574R-R279Q haplotype are significantly associated with the risk of ESCC. Our study shows for the first time that MMP-9 gene P574R polymorphism may contribute to a genetic risk factor for ESCC in a Chinese population.     

Atomic resolution structure of cucurmosin, a novel type 1 ribosome-inactivating protein from the sarcocarp of Cucurbita moschata

A novel type 1 ribosome-inactivating protein (RIP) designated cucurmosin was isolated from the sarcocarp of Cucurbita moschata (pumpkin). Besides rRNA N-glycosidase activity, cucurmosin exhibits strong cytotoxicities to three cancer cell lines of both human and murine origins, but low toxicity to normal cells. Plant genomic DNA extracted from the tender leaves was amplified by PCR between primers based on the N-terminal sequence and X-ray sequence of the C-terminal. The complete mature protein sequence was obtained from N-terminal protein sequencing and partial DNA sequencing, confirmed by high resolution crystal structure analysis. The crystal structure of cucurmosin has been determined at 1.04A, a resolution that has never been achieved before for any RIP. The structure contains two domains: a large N-terminal domain composed of seven alpha-helices and eight beta-strands, and a smaller C-terminal domain consisting of three alpha-helices and two beta-strands. The high resolution structure established a glycosylation pattern of GlcNAc(2)Man(3)Xyl. Asn225 was identified as a glycosylation site. Residues Tyr70, Tyr109, Glu158 and Arg161 define the active site of cucurmosin as an RNA N-glycosidase. The structural basis of cytotoxicity difference between cucurmosin and trichosanthin is discussed.     

Transdifferentiation of mesenchymal stem cells derived from human fetal lung to hepatocyte-like cells

The great shortage of human hepatic cells makes it desirable to generate extrahepatic stem or precursor cells. In recent years, it has been reported that human multipotential mesenchymal stem cells (hMSCs) differentiate into hepatocyte-like cells. The fetal lung is one of the largest organs containing many MSCs that can be easily obtained. Whether MSCs from fetal lung can differentiate into hepatocytes or bile duct cells is an important issue in basic medicine and clinical application. We isolated fetal lung cells, and expanded and analyzed them. At passage 4, their morphologic, immunophenotyping and cytokine secretions were similar to adult bone marrow-derived MSCs. We conclude that these cells from fetal lung are MSCs, indicating that human fetal lung is an ideal source of hMSCs. hMSCs from fetal lung induced in special differentiation medium showed homogeneous and small polygonal endothelial-like morphology, expressing weak mRNA, as well as Alb and AFP. This implies that hMSCs from fetal lung can differentiate into hepatocyte-like cells.     

Screening for antiviral inhibitors of the HIV integrase-LEDGF/p75 interaction using the AlphaScreen luminescent proximity assay

Small-molecule inhibitors of HIV integrase (HIV IN) have emerged as a promising new class of antivirals for the treatment of HIV/AIDS. The compounds currently approved or in clinical development specifically target HIV DNA integration and were identified using strand-transfer assays targeting the HIV IN/viral DNA complex. The authors have developed a second biochemical assay for identification of HIV integrase inhibitors, targeting the interaction between HIV IN and the cellular cofactor LEDGF/p75. They developed a luminescent proximity assay (AlphaScreen) designed to measure the association of the 80-amino-acid integrase binding domain of LEDGF/p75 with the 163-amino-acid catalytic core domain of HIV IN. This assay proved to be quite robust (with a Z' factor of 0.84 in screening libraries arrayed as orthogonal mixtures) and successfully identified several compounds specific for this protein-protein interaction.     

Development of a biochip using antibody-coated gold nanoparticles to detect specific bioparticles

This study developed a method of detecting bioparticles such as Salmonella that exist in the biological samples. The method employed a substrate with interlaced comb-like electrodes into which the mixtures of biological samples and antibody-coated gold nanoparticles were added. The alternative signals with appropriate frequency bands were then conducted into the comb-like electrodes to change the dielectrophoresis force. The gold-modified Salmonella can be adsorbed on the edges of the electrodes and isolated from various biological samples. The impedance of the adsorbed Salmonella on the edges of the electrodes was measured and comparison of the impedance between the electrodes with and without Salmonella can quantify the amount of the adsorbed Salmonella.     

Encapsulated in silica: genome, proteome and physiology of the thermophilic bacterium Anoxybacillus flavithermus WK1

Background

Gram-positive bacteria of the genus Anoxybacillus have been found in diverse thermophilic habitats, such as geothermal hot springs and manure, and in processed foods such as gelatin and milk powder. Anoxybacillus flavithermus is a facultatively anaerobic bacterium found in super-saturated silica solutions and in opaline silica sinter. The ability of A. flavithermus to grow in super-saturated silica solutions makes it an ideal subject to study the processes of sinter formation, which might be similar to the biomineralization processes that occurred at the dawn of life.

Results

We report here the complete genome sequence of A. flavithermus strain WK1, isolated from the waste water drain at the Wairakei geothermal power station in New Zealand. It consists of a single chromosome of 2,846,746 base pairs and is predicted to encode 2,863 proteins. In silico genome analysis identified several enzymes that could be involved in silica adaptation and biofilm formation, and their predicted functions were experimentally validated in vitro. Proteomic analysis confirmed the regulation of biofilm-related proteins and crucial enzymes for the synthesis of long-chain polyamines as constituents of silica nanospheres.

Conclusions

Microbial fossils preserved in silica and silica sinters are excellent objects for studying ancient life, a new paleobiological frontier. An integrated analysis of the A. flavithermus genome and proteome provides the first glimpse of metabolic adaptation during silicification and sinter formation. Comparative genome analysis suggests an extensive gene loss in the Anoxybacillus/Geobacillus branch after its divergence from other bacilli.     

Ingested energy differs between populations of the toad Bufo bankorensis from different altitudes

We measured ingested energy (E(i)) and apparent digestibility efficiency (ADE) in two populations of Bufo bankorensis from different altitudes at three temperatures and during two seasons to test the hypothesis that the optimal temperature range (T(opt)) for E(i) and ADE has shifted to the lower range in highland toads and winter toads. The T(opt) for E(i) was 22 degrees C for the lowland and highland toads and did not vary between seasons, thus falsifying the hypothesis. ADE of the toads was 96%-99% at 15 degrees -30 degrees C, and there was no difference between populations or seasons. Furthermore, when fed with fast-moving prey, the toads from both altitudes had similarly low E(i) at 15 degrees C; when fed with slow-moving prey, the highland toads increased E(i) at 15 degrees C, but the lowland toads did not. These results suggest that the toads from different altitudes had different appetites, even though their feeding locomotion was hampered in both populations at low temperatures.     

丹霞地貌山顶生态效应

首次探讨了丹霞地貌山顶生态效应现象,揭示特殊的地貌、形态所产生的特殊生态现象.测定广东省丹霞山宝珠峰和海螺峰的山顶的生态因子特征、群落结构特征和物种生态型特征,并与山脚的群落与种群以及相近非丹霞地貌区作比较.结果表明,山顶的平均温度高于山脚沟谷,平均湿度小于山脚沟谷,群落物种数和物种多样性均小于山脚沟谷.相比山顶而言,山脚沟谷的植物有很强的热带性.这些特征都有别于一般非丹霞地貌山地.另外,在山顶和山脚调查的几个种群在叶面积、比叶面积、树皮、枝下高和冠幅等方面,均出现了生态型的差异.讨论了丹霞地貌山顶对生态型研究、岛屿理论研究和适应性进化研究的科学意义.