生物异源物传感系统研究进展

生物异源物与人体的关系本质上是它们与基因组及其产物的相互作用 ,生物异源物通过特定靶点 (效应系统 )作用于人体 ,而人体则以生物转化酶和转运载体 (处置系统 )来消除影响以维持稳定。生物异源物传感系统介导了环境化学信息传递给基因组并诱导处置系统的表达和作为 ,调控CYP3A和MDR1诱导表达的核受体PXR(NR1I2 )是该系统的重要成员。PXR等核受体传感许多生物异源物的刺激并诱导多个基因的表达 ,它们的底物和靶基因有某些交叉性。研究PXR等的结构与功能 。

异源物代谢核受体PXR和CAR在血管疾病中的作用

孕烷X受体(pregnant X receptor,PXR)和组成型雄甾烷受体(constitutive androstane receptor,CAR)是核受体(nuclear receptors,NRs)超家族的重要成员,主要分布在肝脏和小肠等组织,经配体激活后可调控药物代谢酶及转运体的表达和活性,调节毒性物质的清除、解毒及代谢,保护机体免受外源性化学物质和内源性毒性脂质损伤。因此,PXR和CAR也被称为异源物代谢核受体(xenobiotic nuclear receptors)。近年发现,PXR和CAR也参与糖、脂代谢和炎症等信号通路的调控,同时,在血管内皮细胞也有表达,从而可能与动脉粥样硬化、高血压等血管疾病的发生密切相关。本文简要综述PXR和CAR的结构、组织分布、配体、激活及其在血管疾病中的作用。

异源物核受体激活机制在调控药物代谢中的研究现状

核受体(NRs)是一种转录调控因子,能够在转录水平上对药物代谢酶和转运体的表达进行调控,其中雄甾烷受体(CAR)和孕甾烷受体(PXR)均属于核受体家族中的异源物核受体(XRs)。XRs作为细胞传感器,能够接受各种内源和外源性物质的刺激,并调控药物代谢酶和转运体基因的转录水平。CAR和PXR都能够通过配体依赖(直接激活)和非配体依赖(间接激活)两种方式,被不同的化学物质激活,进而影响药物代谢酶和转运体的表达,对药物代谢过程进行调控。本文综述了CAR和PXR不同激活途径的信号通路,为临床药物代谢和药物相互作用研究提供参考。

异源植物提取物对香蕉交脉蚜的控制作用

测定了 2 3种异源植物提取物对香蕉交脉蚜的忌避作用和致死作用 ,结果表明 :处理 2 4h后蓖麻、夹竹桃对香蕉交脉蚜定居取食的干扰效果好 ,忌避作用指数在 0 .1以下 ;马樱丹、番茄、飞机草和鳞花草对香蕉交脉蚜忌避作用较强 ,忌避作用指数为 0 .1～ 0 .3;忌避作用指数为 0 .3～ 0 .5的有千头柏、牵牛花、白花非洲山毛豆、马尾松和走马箭。处理后 4 8h ,大部分植物提取物对香蕉交脉蚜的忌避作用明显降低 ;处理后 72h ,大部分植物提取物的忌避作用指数接近于 1,说明对香蕉交脉蚜的定居取食干扰作用已很弱。绝大部分植物提取物对香蕉交脉蚜的致死作用不强。处理后 72h ,仅蓖麻、马樱丹存活指数低于 0 .5 ,即处理的蚜虫存活率在对照的5 0 %以下。另外效果较好的有夹竹桃、飞机草、白花非洲山毛豆等。

异源物核受体基因多态性与奥卡西平治疗癫癎患者临床疗效的相关性研究

目的分析异源物核受体的组成型雄甾烷受体(CAR)、孕烷X受体(PXR)和芳香烃受体(AHR)的基因多态性与奥卡西平抗癫癎疗效的相关性。方法共入组应用奥卡西平治疗的192例癫癎患者,根据奥卡西平的疗效分为耐药组(98例)和药物反应组(94例),采用MALDI-TOF质谱法对PXR、CAR和AHR的15个候选单核苷酸多态性(SNP)进行基因型检测。结果耐药组患者起病年龄小、病程较药物反应组长(P<0.001),脑电图阳性率高于药物反应组(P<0.05),组间差异有统计学意义。经校正年龄、病程、脑电图和剂量/体质量比(D/W)等混杂因素后,CAR rs2307424GA型(P=0.011)与耐药显著相关,GA基因型患者较其他基因型患者发生奥卡西平耐药的概率高。AHR rs7811989 GA型与耐药呈显著相关(P=0.035)。结论中国癫癎患者的异源物核受体PXR、CAR和AHR的基因多态性与奥卡西平疗效具有相关性,携带CAR rs2307424 GA型和AHR rs7811989 GA型患者更容易发展为奥卡西平耐药。

2株邻苯二甲酸酯高效降解菌的筛选鉴定及其降解性能

为获得用于修复邻苯二甲酸酯(PAEs)污染的高效降解菌,通过富集培养的方法从土壤中筛选出2株PAEs降解菌(RXX-2、RXX-3),经形态观察、生化鉴定和16SrDNA序列分析对菌株进行了鉴定,并对其降解性能进行了分析。结果表明:菌株RXX-2和RXX-3初步鉴定为食异源物鞘氨醇菌(Sphingobium xenophagum)和鳗败血假单胞菌(Pseudomonas anguilliseptica)。菌株RXX-2降解PAEs的最佳条件为pH8、温度30℃、转速175r min^-1、接种量1.5%;菌株RXX-3降解PAEs的最佳条件为pH7、温度30℃、转速175r min^-1、接种量1.0%。在最佳降解条件下,经过5d的培养,菌株RXX-2对邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二(2-乙基己基)酯(D EHP)的降解率分别达到71.43%和52.85%,RXX-3对DBP和DEHP的降解率分别达到98.98%和62.96%,表明2株降解菌在PAEs污染环境的生物修复方面具有良好的应用前景。

细胞色素P450与肿瘤发生相关性的研究进展

细胞色素P450（cytochromeP450，CYP450）酶超家族在体内起到代谢异源性物质的重要作用。在人类已知的57个CYP450同工酶中，有7种亚型酶负责了90％以上临床常用药物的代谢清除，即：

Spatio-temporal distribution of net-collected phytoplankton community and its response to marine exploitation in Xiangshan Bay

To explore the spatial-temporal distribution of the phytoplankton community and evaluate the combined effects of marine resource exploitation, net-collected phytoplankton and physical-chemical parameters were investigated in the Xiangshan Bay during the four seasons of 2010. A total of eight phyla, 97 genera, and 310 species were found, including 232 diatom species, 45 dinoflageUate species and 33 other taxa. The phytoplankton abundances presented a significant （P〈0.001） seasonal difference with the average of 60.66x104 cells/m3. Diatoms （mainly consisting of Coscinodiscus jonesianus, Cerataulina pelagica, Skeletonema costatum, and genus Chaetoceros） dominated the phytoplankton assemblage in all seasons. We found great spatio-temporal variation in community composition based on the multidimensional scaling and similarity analysis. Canonical correspondence analysis show that temperature, nutrition, illumination, and salinity were the main variables associated with microalgal assemblage. Compared with the previous studies, an increase in phytoplankton abundance and change in the dominant species coincided with increased exploitation activities in this bay （e.g. operation of coastal power plants, intensive mariculture, tidal fiat reclamation, and industrial and agricultural development）. The present findings suggest that the government should exercise caution when deciding upon developmental patterns in the sea-related economy.

Physical-layer security enhancement method for wireless HetNets via transmission pair scheduling

In order to enhance the physical-layer security of wireless transmission in a wireless heterogeneous network (HetNet), a two-stage-based cooperative framework is advocated. To be specific, a source-destination (SD) pair is opportunistically chosen at the beginning of the transmission slot, which can be used to assist the transmissions of other SD pairs. Under this framework, a transmit antenna selection assisted opportunistic SD pair scheduling (TAS-OSDS) scheme is proposed, and the intercept probability (IP) of the proposed TAS-OSDS, the conventional round-robin source-destination pair scheduling (RSDS) and the conventional non-cooperation (non-coop) schemes is also analyzed, where the RSDS and non-coop schemes are used for comparison with the proposed TAS-OSDS. Numerical results show that increasing the number of the SD pairs can effectively reduce the IP of the TAS-OSDS scheme, whereas the IP of the RSDS and the non-coop remain unchanged with an increasing number of the SD pairs. Furthermore, the TAS-OSDS scheme achieves a lower IP than that of the RSDS and the non-coop schemes, showing the superiority of the proposed TAS-OSDS.

A description of alkaline phosphatases from marine organisms

Alkaline phosphatases(APs) are non-specifi c phosphohydrolases, and they are widely used in clinical diagnostics and biological studies. APs are widespread in nature and exhibit dif ferent structural formulations. Based on the diversity of biogenetic sources, APs exhibit temperature-propensity traits, and they are classifi ed as psychrophilic, mesophilic, and thermophilic. In this article, the characteristics of psychrophilic APs from marine organisms were described, accompanied by a simple description of APs from other organisms. This review will facilitate better utilization of marine APs in the biotechnology fi eld.

Effect of nitrogen to phosphorus ratios on cell proliferation in marine micro algae

The ratio of nitrogen/phosphorus （N/P） is known to affect cell proliferation of some marine micro algae. We evaluated the effect of N/P ratios on the proliferation and succession of phytoplankton using five marine micro algae species. We used two sources of nitrogen, NH4Cl （N1） and urea （N2）, and a single source of phosphorous, NaH2PO4（P）. The optimal N/P ratio that differed among the five species was affected by the source of nitrogen, being as follows （N1/P, N2/P in order）： Thalassiosira sp. （30/1, 20/1）, Heterosigma akashiwo （30/1, 30/1）, Chroornonas salina （20/1, 30/1）, Chaetoceros gracilis （40/1, 60/1）, and A lexandrium sp. （10/1, 30/1）. Thus, the source of nitrogen must be considered when analyzing the N/P ratio. Our results provide insight for predicting phytoplankton succession in coastal waters and may be used to forecast the potential risk of harmful algal blooms.

Morphogenic Variability of Some Autochthonous Plum Cultivars in the Region of North Montenegro

Plum is the major fruit species in the area of North Montenegro. Over a long period of growing in this region, autochthonous cultivars adapted, and have been achieving satisfactory results, despite poor growing conditions. A study conducted over a period of three years in a North Montenegro region included in situ identification of autochthonous plum cultivars. Observation and recording of their phenological and pomological traits were performed using International Board for Plant Genetic Resources （IBPGR） and International union for the Protection of New Varieties of plants （UPOV） methodologies. Eighteen cultivars derived from Prunusdomestica L. and two cultivars derived from P. insititia L. were identified. Flowering started between March 26th and April 12th and fruit ripening between 13th of July （Petrovaca） and 18th September （Trnovaca）. Fruit weight ranged from 6.65 g ± 0.235 g to 53.88 g ± 0.654 g respectively and stone weight from 0.16 g ±0.003 g to 2.20 g ± 0.711 g. The cultivars were classified as being extremely small in terms of fruit size, except for cvs Crvenadurgulja （big fruit size）. Rounded fruit shape and light green ground color were dominant. Skin color ranged from amber to black. Yellow green was a dominant flesh color and medium flesh firmness predominated. The fruits of the above cultivars could be processed, particularly into plum brandy, or they could be used fresh or dried. The selected plum cultivars can be used in breeding programmes, as rootstocks as well as in further disease related systematic studies under field and laboratory conditions.

Approximation of Derivative for a Singularly Perturbed Second-Order ODE of Robin Type with Discontinuous Convection Coefficient and Source Term

In this paper, a singularly perturbed Robin type boundary value problem for second-order ordinary differential equation with discontinuous convection coefficient and source term is considered. A robust-layer-resolving numerical method is proposed. An e-uniform global error estimate for the numerical solution and also to the numerical derivative are established. Numerical results are presented, which are in agreement with the theoretical predictions.

Impacts of global biogenic isoprene emissions on surface ozone during 2000-2019

Biogenic isoprene is an important precursor of tropospheric ozone(O_(3)).Here,a coupled chemistry-vegetation model was used to quantify the contributions of isoprene emissions to surface O_(3)pollution on the global scale during 2000-2019.The biogenic isoprene emissions showed high values in mid-low latitudes and seasonal peaks in the summer hemispheres.They promote global surface O_(3)concentrations by 1.75 ppbv annually with regional hotspots of 4.39 ppbv(8.8%)in China and 5.36 ppbv(11.1%)in the U.S.in boreal summer.In the past two decades,isoprene emissions increased by 1.32 TgC yr^(−1)(0.67%yr^(−1))in the Northern Hemisphere but decreased by 0.71 TgC yr^(−1)(0.44%yr^(−1))in the Southern Hemisphere.Such changes of isoprene made opposite contributions to the surface O_(3)trend,with 0.26 ppbv yr^(−1)in eastern China but−0.32 ppbv yr^(−1)in the southeastern U.S.due to the changes in the background regime of chemical reactions.The impact of anthropogenic changes on the O_(3)trend is consistent with that of biogenic isoprene,but two to four times stronger in magnitude.This study revealed that the effective control of anthropogenic NO_(x)emissions could mitigate regional O_(3)pollution even with the increased isoprene emissions under global warming.

Expression of cytochrome P450 CYP81A6 in rice: tissue specificity, protein subcellular localization, and response to herbicide application

The cytochrome P450 gene CYP81A6 confers tolerance to bentazon and metsulfuron-methyl, two selective herbicides widely used for weed control in rice and wheat fields. Knockout mutants of CYP81A6 are highly susceptible to both herbicides. The present study aimed to characterize the CYP81A6 expression in rice. Quantitative real-time polymerase chain reaction（PCR） analyses demonstrated that foliar treatment of bentazon（500 mg/L） greatly induced expression of CYP81A6 in both wild-type（Jiazhe B） and its knockout mutant（Jiazhe m B）： a 10-fold increase at 9 h before returning to basal levels at 24 h in Jiazhe B, while in the mutant the expression level rose to 20-fold at 12 h and maintained at such high level up to 24 h post exposure. In contrast, metsulfuron-methyl（500 mg/L） treatment did not affect the expression of CYP81A6 in Jiazhe B within 80 h; thereafter the expression peaked at 120 h and returned gradually to basal levels by Day 6. We suggest that a metabolite of metsulfuron-methyl, 1H-2,3-benzothiazin-4-（3H）-one-2,2-dioxide, is likely to be responsible for inducing CYP81A6 expression, rather than the metsulfuronmethyl itself. Use of a promoter-GUS reporter construct（CYP81A6Pro：：GUS） demonstrated that CYP81A6 was constitutively expressed throughout the plant, with the highest expression in the upper surfaces of leaves. Subcellular localization studies in rice protoplasts showed that CYP81A6 was localized in the endoplasmic reticulum. These observations advance our understanding of CYP81A6 expression in rice, particularly its response to the two herbicides.

Rufous-and-white wrens Thryophilus rufalbus do not exhibit a dear enemy effects towards conspecific or heterospecific competitors

Many territorial animals exhibit reduced aggression towards neighbours. Known as ＂the dear enemy effect＂, this phenomenon has been documented among conspecific animals across a wide range of animal taxa. In theory, the dear enemy ef- fect can also exist between individuals of different species, particularly when those species compete for shared resources. To date, a heterospecific dear enemy effects has only been documented in ants. In this study, we test for both a conspecific and heterospe- cific dear enemy effect in neotropical rufous-and-white wrens Thryophilus rufalbus. This species competes for resources with banded wrens Thryophilus pleurostictus, a closely related sympatric congener. We used acoustic playback to simulate ruf- ous-and-white wren and banded wren neighbours and non-neighbours at the edges of rufous-and-white wren territories. Ruf- ous-and-white wrens responded more strongly to signals from their own species, demonstrating that resident males discriminate between conspecific and heterospecific rivals. They did not, however, exhibit a conspecific dear enemy effect. Further, they did not exhibit a heterospecific dear enemy effect. This could be due to neighbours and non-neighbours posing similar levels of threat in this system, to the possibility that playback from the edges of the subjects＇ large territories did not simulate a threatening signal, or to other factors. Our study provides the first test of a heterospecific dear enemy effect in vertebrates, and presents a valuable experimental approach for testing for a heterospecific dear enemy effect in other animals [Current Zoology 61 （1）： 23-33, 2015].

Mining of a streptothricin gene cluster from Streptomyces sp.TP-A0356 genome via heterologous expression

Streptothricins (STs) are used commercially to treat bacterial and fungal diseases in agriculture. Mining of the sequenced microbial genomes uncovered two cryptic ST clusters from Streptomyces sp. C and Streptomyces sp. TP-A0356. The ST cluster from S. sp. TP-A0356 was verified by successful heterologous expression in Streptomyces coelicolor M145. Two new ST analogs were produced together with streptothricin F and streptothricin D in the heterologous host. The ST cluster was further confirmed by inactivation of gene stnO, which was proposed encoding an aminomutase supplying -lysines for the poly-β-Lys chain formation. A putative biosynthetic pathway for STs is proposed based on bioinformatics analyses of the ST genes and experimental evidence.

Do predator energy demands or previous exposure influence protection by aposematic coloration of prey？

Growing evidence exists that aposematic and toxic prey may be included in a predator＇s diet when the predator experiences physiological stress. The tree sparrow Passer montanus is known to have a significant portion of aposematic and toxic ladybirds in its natural diet. Here, we present experi- ments testing the attack and eating rate of the tree sparrow toward the invasive aposematic harle- quin ladybird Harmonia axyridis. We wondered whether the sparrow＇s ability to prey on native ladybirds predisposes them to also prey on harlequin ladybirds. We compared the attack and eat- ing rates of tree sparrows of particular age and/or experience classes to test for any changes during ontogeny （hand-reared x young wild-caught xadult wild-caught） and with differing perceived lev- els of physiological stress （summer adult ~ winter adult）. Winter adult tree sparrows commonly at- tacked and ate the offered ladybirds with no evidence of disgust or metabolic difficulties after in- gestion. Naive and wild immature tree sparrows attacked the ladybirds but hesitated to eat them. Adult tree sparrows caught in the summer avoided attacking the ladybirds. These results suggest that tree sparrows are able to cope with chemicals ingested along with the ladybirds. This pre- adaptation enables them to include ladybirds in their diet; though they commonly do this only in times of shortage in insect availability （winter）. Young sparrows showed avoidance toward the chemical protection of the ladybirds.

ON THE UNIQUENESS OF THE WEAK SOLUTIONS OF A QUASILINEAR HYPERBOLIC SYSTEM WITH A SINGULAR SOURCE TERM

This paper is a continuation of the authors' previous paper [1]. In this paper the authors prove, assuming additional conditions on the initial data, some results about the existence and uniqueness of the entropy weak solutions of the Cauchy problem for the singular hyperbolic system