贵州环口螺科一新种记述(前鳃亚纲,中腹足目,环口螺科)

在整理贵州省贵阳地区陆生贝类标本时,经鉴定发现1新种,即奇异阿勇螺Arinia mirifica sp.nov..隶属于前鳃亚纲、中腹足目、环口螺科、阿勇螺属.对新种形态特征、栖息环境进行了记述,并对其近似种也进行了讨 论.     

Speciation, Distribution, and Bioavailability of Soil Selenium in the Tibetan Plateau Kashin–Beck Disease Area—A Case Study in Songpan County, Sichuan Province, China

To clarify the relationship between the soil selenium distribution and its bioavailability with the distribution of Kashin–Beck disease (KBD) endemic areas on the eastern edge of the Tibetan Plateau, samples of natural soil (0–20 cm), cultivated topsoil, and main crops of the region (highland barley) were collected at different altitudes according to topographical and geomorphological features in both KBD and non-KBD areas of Songpan County. These samples were used for determination and analysis of total selenium content in soil and highland barley and available selenium that can be absorbed and utilized by plants. The results showed that the average total selenium content of natural and cultivated topsoil in KBD areas was lower than that in non-KBD areas (natural soil, P?=?0.061; cultivated soil, P?=?0.002), which is in agreement with the geographical distributions of selenium in other KBD-affected areas. However, the total soil selenium content exhibits certain micro-spatial distribution features, namely, the total selenium content in some endemic areas was significantly higher than that of non-KBD areas. This result was contrary to the general distribution that total selenium content in a KBD-affected area is lower than that in a non-KBD area. We further studied the extraction rate and content of soil selenium in six different fractions. The results indicated that the content and extraction rate of available selenium in KBD-affected areas were significantly lower than those in non-KBD areas. There is a distinct positive correlation between plant-available selenium and highland barley selenium (r?=?0.875, P?=?0.001) and a distinct negative correlation with altitude (r?=??0.801, P?=?0.010). Therefore, in KBD endemic areas, the selenium content in crops decreases as the available selenium content in soil decreases and is closely related to the geographical environment features (such as altitude and precipitation). These results suggest that the soil available selenium and ecological features are important factors that restrict the dietary selenium flux for residents in KBD endemic areas of the Tibetan Plateau, providing a theoretical and experimental basis for implementing agricultural measures to regulate the ecological cycle of the selenium flux in the KBD endemic area.     

Risk Factors for Poor Treatment Outcomes in Patients with MDR-TB and XDR-TB in China: Retrospective Multi-Center Investigation

Background

The treatment of patients with MDR- and XDR-TB is usually more complex, toxic and costly and less effective than treatment of other forms of TB. However, there is little information available on risk factors for poor outcomes in patients with MDR- and XDR-TB in China.

Methodology/Principal Findings

We retrospectively analyzed the clinical records of HIV-negative TB Patients with culture-proven MDR- or XDR-TB who were registered from July 2006 to June 2011 at five large-scale Tuberculosis Specialized Hospitals in China. Among 1662 HIV-seronegative TB cases which were culture-positive for M. tuberculosis complex and had positive sputum-smear microscopy results, 965 cases (58.1%) were DR-TB, and 586 cases (35.3%) were classified as having MDR-TB, accounting for 60.7% of DR-TB. 169 cases (10.2%) were XDR-TB, accounting for 17.5% of DR-TB, 28.8% of MDR-TB. The MDR-TB patients were divided into XDR-TB group (n=169) and other MDR-TB group (non-XDR MDR-TB) (n=417). In total, 240 patients (40.95%) had treatment success, and 346 (59.05%) had poor treatment outcomes. The treatment success rate in other MDR-TB group was 52.2%, significantly higher than that in the XDR-TB group (13%, P<0.001). In multivariate logistic regression analysis, poor outcomes were associated with duration of previous anti-TB treatment of more than one year (OR, 0.077; 95% CI, 0.011-0.499, P<0.001), a BMI less than 18.5 kg/m² (OR, 2.185; 95% CI, 1.372-3.478, P<0.001), XDR (OR, 13.368; 95% CI, 6.745-26.497, P<0.001), retreatment (OR, 0.171; 95% CI, 0.093-0.314, P<0.001), diabetes (OR, 0.305; 95% CI, 0.140-0.663, P=0.003), tumor (OR, 0.095; 95% CI, 0.011-0.795, P=0.03), decreased albumin (OR, 0.181; 95% CI, 0.118-0.295, P<0.001), cavitation (OR, 0.175; 95% CI, 0.108-0.286, P<0.001).

Conclusions/Significance

The patients with MDR-TB and XDR-TB have poor treatment outcomes in China.The presence of extensive drug resistance, low BMI, hypoalbuminemia, comorbidity, cavitary disease and previous anti-TB treatment are independent prognostic factors for poor outcome in patients with MDR-TB.     

基于DSSAT模型对豫北地区夏玉米灌溉制度的优化模拟

合理的灌溉制度是提高农业水资源利用效率、保证夏玉米高产稳产的前提。采用农业技术转化决策系统(DSSAT,Decision Support System for Agrotechno1ogy Transfer)探究了河南省北部地区夏玉米不同降水年型下的最优灌溉制度。经过参数的校正和验证,归一化均方根误差(nRMSE)、均方根误差(RMSE)和一致性指数(d)均表现出模拟值与实测值的吻合度很好,DSSAT-maize模型可以准确模拟夏玉米物候期、地上部分生物量、产量和土壤水分状况。然后基于模型模拟了不同灌溉处理下的夏玉米生产潜力,从而评估夏玉米缺水量,并对比分析不同生育时期灌水对产量的影响确定最优灌溉时期,综合考虑产量和水分利用效率确定最优灌溉制度。结果表明:夏玉米生长季的缺水量年际间差异显著,多年平均值为38.91 mm,波动范围为0—193.03 mm。在丰水年,不需要灌溉;在平水年,开花期灌水30 mm;在枯水年,开花期和灌浆期灌水50 mm;在特别干旱年,苗期、拔节期和开花期至少灌水180 mm。优化的灌溉制度下丰水年、平水年和枯水年的WUE达到最高且产量分别占其最高产量的100%、99.72%和97.89%,实现了作物高产节水协同提高的目标。     

Doxorubicin‐induced cardiotoxicity is maturation dependent due to the shift from topoisomerase IIα to IIβ in human stem cell derived cardiomyocytes

Doxorubicin (DOX) is widely used to treat various cancers affecting adults and children; however, its clinical application is limited by its cardiotoxicity. Previous studies have shown that children are more susceptible to the cardiotoxic effects of DOX than adults, which may be related to different maturity levels of cardiomyocyte, but the underlying mechanisms are not fully understood. Moreover, researchers investigating DOX‐induced cardiotoxicity caused by human‐induced pluripotent stem cell‐derived cardiomyocytes (hiPSC‐CMs) have shown that dexrazoxane, the recognized cardioprotective drug for treating DOX‐induced cardiotoxicity, does not alleviate the toxicity of DOX on hiPSC‐CMs cultured for 30 days. We have suggested that this may be ascribed to the immaturity of the 30 days hiPSC‐CMs. In this study, we investigated the mechanisms of DOX induced cardiotoxicity in cardiomyocytes of different maturity. We selected 30‐day‐old and 60‐day‐old hiPSC‐CMs (day 30 and day 60 groups), which we term ‘immature’ and ‘relatively mature’ hiPSC‐CMs, respectively. The day 30 CMs were found to be more susceptible to DOX than the day 60 CMs. DOX leads to more ROS (reactive oxygen species) production in the day 60 CMs than in the relatively immature group due to increased mitochondria number. Moreover, the day 60 CMs mainly expressed topoisomerase IIβ presented less severe DNA damage, whereas the day 30 CMs dominantly expressed topoisomerase IIα exhibited much more severe DNA damage. These results suggest that immature cardiomyocytes are more sensitive to DOX as a result of a higher concentration of topoisomerase IIα, which leads to more DNA damage.     

反硝化基因工程菌株YP4S的构建及对污水除氮特性研究

从养殖场污泥中筛选出菌株YP4,经16S rDNA分子发育树的同源序列比对,确定为克雷伯什菌属(Klebsiella sp.)。由NCBI数据库查编码亚硝酸还原酶(Nir)的基因nirS序列,设计引物,以铜绿假单胞菌PAOI基因组DNA为模板,应用PCR技术扩增目的片段nirS,经过双酶切、克隆和转化,得到重组质粒pYP4S,然后转化野生菌株YP4,构建反硝化基因工程菌YP4S。菌株生长曲线测定表明,工程菌株YP4S与YP4的生长特性基本一致。工程菌株YP4S对模拟污水COD、TN、NH_4^+-N和NO_3^--N具有较高的去除率,YP4S与YP4相比,对NO_2^--N积累的减少量为(32.44±3.96)%,明显减少了NO_2^--N的积累。通过正交试验获得工程菌株YP4S在C/N=10、T=30℃、r=200 r/min和pH=7.0的最佳组合条件下,对模拟污水TN去除率较高。应用工程菌株YP4S处理猪场沉淀池的实际污水,COD、TN、TP、NH_4^+-N和NO_3^--N去除率分别为(95.87±0.82)%、(76.38±3.84)%、(97.13±0.54)%和(75.35±2.57)%,NO_2^--N积累量为(3.31±1.24) mg/L,表明工程菌株YP4S具有较好反硝化作用,对含氮量高的实际污水修复具有潜在的应用前景。     

河南西峡盆地晚白垩世含恐龙蛋地层中的介形类

河南西峡盆地含恐龙蛋地层高沟组、马家村组和寺沟组共发现介形类13属(亚属)20种,其中高沟组和寺沟组的介形类为首次报道.文章重点讨论了介形类Talicyridea动物群,其中Talicypridea,Altanicypris,Ruficypris和Lunicypris属的地质历程均限于晚白垩世.依据Talicyprid...     

食品常见真菌毒素的危害及其防止措施

真菌毒素是一类由真菌产生的普遍存在的化合物。危害人类健康的真菌毒素主要源于曲霉Aspergillus、青霉Penicil-lium、麦角菌属Claviceps和镰刀菌Fusarium等产生的次生代谢物。从全球范围来看,粮食安全问题经常是由谷物、坚果、水果和绿色咖啡豆上的真菌毒素造成的。其中,玉米和花生仁中的黄曲霉素经常超过安全阈值。在以这些食物作为主食的地处温暖和潮湿气候国家的消费者特别容易食用到黄曲霉素污染的食物。而真菌毒素往往会引起人类和动物急性中毒、慢性中毒和致癌。其不可避免地、广泛地、持续地影响着全球人类的健康。目前的防止措施包括选用抗真菌植物、采用适当方法贮藏食物以及食用绿色蔬菜等来预防癌症等。本文阐述了食品中常见真菌毒素的污染情况及其毒性,并对常用防止措施进行了综述,以期为食品真菌毒素防控工作提供参考。     

胡瓜钝绥螨对日光大棚茄子上烟粉虱的控制作用

为了评价胡瓜钝绥螨在我国日光大棚中对茄子上烟粉虱虱的控制作用。笔者研究了在24～34℃下胡瓜钝绥螨以烟粉为猎物时的发育历期,并在我国山东省寿光市的蔬菜基地上开展了利用胡瓜钝绥螨控制日光大棚茄子上烟粉虱的研究与应用。结果表明:胡瓜钝绥螨能够取食烟粉虱的卵、成虫、若虫及伪蛹;利用胡瓜钝绥螨能有效地控制烟粉虱成虫、卵、若虫种群数量的增长。根据胡瓜钝绥螨和烟粉虱的生物学特性,结合大棚茄子栽培过程中的环境条件,笔者提出了在日光大棚中应用胡瓜钝绥螨控制茄子上烟粉虱的策略:(1)在茄子的整个生长季节(250d)中需释放胡瓜钝绥螨4～6次,苗期每次每株释放5～10头,结果期每次每株释放20～40头;(2)释放胡瓜钝绥螨的生防区比常规化防区减少农药使用18次;(3)安装防虫网、适时释放胡瓜钝绥螨是生防成功之关键,生防区配合使用黄板效果更好。     

核层蛋白A前体的法尼基化与衰老

编码核层蛋白A(lamin A)的LMNA基因突变导致法尼基化的核层蛋白A前体(prelamin A)不能被进一步加工成成熟的核层蛋白A,从而导致一种Hutchinson-Gilford早老症综合征(Hutchinson-Gilford progeria syndrome,HGPS)。一种更严重的早老症——限制性皮肤病(restrictive dermopathy,RD),是由于缺失核层蛋白A前体加工过程中的剪切酶ZMPSTE24引起的。ZMPSTE24的缺失阻止了法尼基化的核层蛋白A前体不能正常加工成为成熟的核层蛋白A,同时导致法尼基化的核层蛋白A前体的堆积。在HGPS和RD病人的成纤维细胞中,发现法尼基化的核层蛋白A前体都定位在核膜,从而影响细胞核膜的完整性,并导致细胞核形的异常,进而导致衰老。最近研究表明经过法尼基酰转移酶抑制剂(farnesyltransferase inhibitor,FTI)处理后的细胞的核形异常减少。同时,FTI能够改善HGPS和RD小鼠的早老症状。本文就核层蛋白A前体的法尼基化对衰老的影响有关研究进展作一综述。