一株降解煤油菌株的筛选与鉴定

本文通过从污水处理厂活性污泥中分离得到一株高效降解轻油(煤油)细菌5092-2,通过形态学、16S rRNA鉴定该菌为Mangroveibacter sp.。进一步对其生长条件进行了研究,发现该菌在23℃到38℃、pH为5.0到9.0范围内生长无明显差异。在温度为35℃,pH 7.2~7.4,160 r/min培养7 d,菌株降解煤油的能力达到52.3%,具有进一步研究的价值。     

Shifts in potential geographical distribution of Pterocarya stenoptera under climate change scenarios in China

Climate change poses a serious threat to biodiversity. Predicting the effects of climate change on the distribution of a species' habitat can help humans address the potential threats which may change the scope and distribution of species. Pterocarya stenoptera is a common fast‐growing tree species often used in the ecological restoration of riverbanks and alpine forests in central and eastern China. Until now, the characteristics of the distribution of this species' habitat are poorly known as are the environmental factors that influence its preferred habitat. In the present study, the Maximum Entropy Modeling (Maxent) algorithm and the Genetic Algorithm for Ruleset Production (GARP) were used to establish the models for the potential distribution of this species by selecting 236 sites with known occurrences and 14 environmental variables. The results indicate that both models have good predictive power. Minimum temperature of coldest month (Bio6), mean temperature of warmest quarter (Bio10), annual precipitation (Bio12), and precipitation of driest month (Bio14) were important environmental variables influencing the prediction of the Maxent model. According to the models, the temperate and subtropical regions of eastern China had high environmental suitability for this species, where the species had been recorded. Under each climate change scenario, climatic suitability of the existing range of this species increased, and its climatic niche expanded geographically to the north and higher elevation. GARP predicted a more conservative expansion. The projected spatial and temporal patterns of P. stenoptera can provide reference for the development of forest management and protection strategies.     

Extremely high prevalence of neural tube defects in a 4-county area in Shanxi Province, China

BACKGROUND: In the past, northern China's Shanxi Province has reported the highest incidence of neural tube defects (NTDs) in the world. However, little is known about the epidemiology of NTDs in this area in recent years. METHODS: Data were collected from a population-based birth defects surveillance system in 4 counties that captures information on all live births, stillbirths of at least 20 weeks' gestation, and pregnancy terminations at any gestational age resulting from prenatal diagnosis of a birth defect. We also surveyed mothers of NTD case patients to determine their use of folic acid before and during early pregnancy. RESULTS: During 2003, 160 NTD cases were identified among 11,534 births (NTD birth prevalence = 138.7/10,000 births). The rates of anencephaly, spina bifida and encephalocele were 65.9, 58.1, and 14.7 per 10,000, respectively, and a female predominance was observed among anencephaly cases (male-to-female relative risk [RR], 0.49; 95% confidence interval [CI], 0.30-0.79), but not among spina bifida (RR, 0.90; 95% CI, 0.55-1.45) and encephalocele (RR, 1.03; 95% CI, 0.40-2.69) cases. The percentages of pregnancy termination following prenatal diagnosis of anencephaly, spina bifida, and encephalocele were 50%, 41.8%, and 35.3%, respectively. NTD birth prevalence tended to be higher among mothers aged <20 or > or =30 years (P = .06) and was markedly associated with lower levels of maternal education (P < .001). Among 143 NTD mothers, only 6 (4.2%) used folic acid supplements during the periconceptional period. CONCLUSIONS: The NTD birth prevalence rate in the study area is among the highest worldwide. Folic acid deficiency may be one important risk factor.     

Synthesis and biological evaluation of a series of novel pyridinecarboxamides as potential multi-receptor antipsychotic drugs

In previous study, a series of benzamides was identified as potent antipsychotic agents. As a continuation of the program to discover novel antipsychotics, herein we reported the evaluation of a series of pyridinecarboxamide derivatives. The most promising compound 7h not only held good activities on dopamine D₂, serotonin 5-HT_1A and 5-HT_2A receptors, but also exhibited low potency for α_1A, H₁ and 5-HT_2C receptors, indicating a low propensity of side effects like orthostatic hypotension and weight gain. Furthermore, 7h exhibited more potent antipsychotic-like effect than aripiprazole in behavioral studies. The preliminary results were promising enough for further research around this scaffold.     

Deciphering the role of dimer interface in intrinsic dynamics and allosteric pathways underlying the functional transformation of DNMT3A

Background

DNMT3A, as de novo DNA methyltransferase, is essential for regulating gene expression through cellular development and differentiation. The functions of DNMT3A rely on its oligomeric states and allosteric regulations between its catalytic domain and binding partners. Despite recent resolution of autoinhibitory and active DNMT3A/3L crystal structures, the mechanism of their functional motions and interdomain allostery in regulating the activity remains to be established.

角蛋白降解能力差异菌株筛选体系的建立

以微生物降解为主的羽毛生物炼制是资源化利用其的重要手段之一,但机理不明是限制其进一步应用的瓶颈。突变体库筛选性状变异菌株的正向遗传学是研究分子机理的常用方案,该方案要求高效可靠的筛选方法。然而,目前依靠测酶活方法来决定降解能力,费时费力,难以用于大规模筛选。本文通过优化羽毛培养基成分及接种菌浓度,建立了一种用于筛选不同角蛋白降解能力微生物的筛选体系。利用该体系分析由mini Tn10构建的S. maltophinia DHHJ突变体库,得到了6株羽毛角蛋白降解能力减弱的突变体,筛选结果与酶活测试100%一致。该研究结果为寻找与角蛋白降解相关基因奠定了基础。     

Inhibitory Effect of Slit2-N on VEGF165-induced proliferation of vascular endothelia via Slit2-N-Robo4-Akt pathway in choroidal neovascularization

Researches have been focusing on the role of Slit2 in angiogenesis, specifically in cell migration and vessel permeability. Nevertheless, the role of Slit2-N, the bioactive fragment of Slit2, in the proliferation of vascular endothelia in choroidal neovascularization and some related mechanisms have not been studied yet. Thus, our study aimed to explore the role of Slit2-N in proliferation of vascular endothelia and the related mechanisms in choroidal neovascularization. Fluorescein isothiocyanate perfusion and HE staining were performed to evaluate volumes of choroidal neovascularization lesions. The effect of Slit2-N on VEGF165-induced cell proliferation and some related mechanisms were detected by CCK8 assay, flow cytometry, siRNA transfection, and western blotting. We found that Slit2-N reduced volumes of laser-induced choroidal neovascularization networks in vivo. Results of the in vitro study showed Slit2-N reduced VEGF165-induced cell proliferation of both human umbilical vascular endothelial cells and human microvascular endothelial cells possibly via activation of AKT rather than that of ERK1/2. Additionally, Robo4, one of the receptors binding to Slit2-N, was involved in the inhibitory effect of Slit2-N. Generally, our findings revealed the inhibitory role of Slit2-N in proliferation of vascular endothelia and some related mechanisms, and presented some potential targets, molecules along Slit2-N-Robo4-AKT axis, to choroidal neovascularization therapy.     

Nature brings new avenues to the therapy of central nervous system diseases——an overview of possible treatments derived from natural products

Natural products(NPs), including traditional Chinese medicine(TCM), have been long and widely used in the prevention and treatment of central nervous system(CNS) diseases by virtue of their abundant sources, diverse structures, and novel activities.In this review article, we intend to summarize and discuss the situation or status of the clinical employments or trials of the NPs and their derivatives with CNS activities. NPs that have been extensively studied in preclinical research in recent years are also included. The compounds presented in this review are classified according to their indications and followed by details such as natural sources, possible biological mechanisms, and development status, while a considerable proportion of them are found in TCM. In addition, some drug combinations with synergistic effects are also mentioned. According to their impressive therapeutic effects and novel chemical structures, NPs are not only effective therapeutic remedies in clinic, but also lead compounds for structural modification, which indicate that nature brings new avenues to the therapy of CNS diseases.