Echinoid spawning induced by a radial nerve factor

An extract of radial nerves of the sea urchin. Strongylocentrotus purpuratus, induces spawning within 1 minute in this species as well as in other echinoids, but a delayed spawning in several asteroid species. The concentration of the spawn-inducing factor in the radial nerves fluctuates annually correlated with the reproductive season of this species along the coast of southern California.     

广东省猪十二指肠贾第虫感染现状和分子特征分析

【目的】 了解广东省不同地区猪源十二指肠贾第虫(Giardia duodenalis,简称贾第虫)的流行现状和分子特征,并评估其人兽共患风险。【方法】 从广东省10个地区采集新鲜猪粪样品,采用显微镜镜检,并应用巢式PCR对贾第虫谷氨酸脱氢酶(glutamate dehydrogenase,gdh)基因进行扩增,根据扩增结果计算不同地区和生长阶段猪贾第虫的阳性率。对所有的PCR阳性产物进行测序,将获得的贾第虫gdh基因序列进行BLAST比对,确定贾第虫的基因型;运用Mega 7.0软件的最大似然法构建进化树。【结果】 贾第虫包囊呈椭圆形,囊壁较厚,大小为(10~14)μm ×(7~10)μm,具有明显纵向轴柱,细胞核分布于轴柱两侧。521份受检样品中共检测出94份PCR阳性样品,阳性率为18.04%(94/521),其中茂名和清远的阳性率较高,分别达40.00%(10/25)和35.06%(27/77);肇庆和韶关的阳性率较低,分别为3.90%(3/77)和8.57%(3/35);佛山、江门、阳江、河源、广州和惠州的阳性率分别为11.11%(2/18)、15.31%(15/98)、11.43%(4/35)、13.33%(4/30)、9.38%(3/32)和24.47%(23/94)。不同饲养阶段的猪群的阳性率调查发现,母猪的贾第虫阳性率(24.55%)显著高于断奶仔猪(13.30%)(P<0.05),与育肥猪的贾第虫阳性率(19.23%)差异不显著(P>0.05)。基于gdh基因序列的基因分型和系统进化分析共发现5种贾第虫亚集聚体,即集聚体AⅠ和集聚体E的4种不同亚型,包括集聚体E1、E2、E10和E13,其中61.70%(58/94)测序阳性样品属于集聚体AⅠ,38.30%(36/94)属于集聚体E的不同亚型。【结论】 广东猪源贾第虫的感染较普遍,不同地区和不同生长阶段的猪感染率存在一定差异。其中,人兽共患性集聚体AⅠ为优势亚集聚体,表明广东省猪源贾第虫存在人兽跨物种传播的风险,应重视该病可能引起的公共卫生问题。     

Marinopyrrole Derivatives as Potential Antibiotic Agents against Methicillin-Resistant Staphylococcus aureus (III)

The marine natural product, marinopyrrole A (1), was previously shown to have significant antibiotic activity against Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Although compound (1) exhibits a significant reduction in MRSA activity in the presence of human serum, we have identified key modifications that partially restore activity. We previously reported our discovery of a chloro-derivative of marinopyrrole A (1a) featuring a 2–4 fold improved minimum inhibitory concentration (MIC) against MRSA, significantly less susceptibility to serum inhibition and rapid and concentration-dependent killing of MRSA. Here, we report a novel fluoro-derivative of marinopyrrole A (1e) showing an improved profile of potency, less susceptibility to serum inhibition, as well as rapid and concentration-dependent killing of MRSA.     

The omnivorous predator Macrolophus pygmaeus induces production of plant volatiles that attract a specialist predator

Journal of Pest Science - It has become clear that omnivorous predators can induce plant defences that affect the performance and host plant choice of herbivores. They are also known to induce the...     

Impact of natural and man-made factors on migration of heavy metals in the Ardon River basin (North Ossetia)

Purpose

The main goal of the study was to evaluate biogeochemical effects of particular factors changing the structure of landscapes due to enhanced mass migration and erosion of the outcropping rocks by studying transformation of chemical composition of the draining waters and flood plain soils; chemical composition of the solid and liquid phases of the Ardon River waters; and by assessing ecological consequences and risk of contamination of the area by heavy metals.

Materials and methods

Water, soil, and biota species (plants, algae, and amphibian) were sampled at the plots located up- and downstream the mining and industrial areas of North Ossetia (the Ardon River basin) before and after the mudflow that took place in 2002. The air-dried samples were decomposed in a mixture of mineral acids. Heavy metals were determined by means of AAS with the help of AAS-80 (Hitachi) or AAS-2A (KORTEC) using standard reference materials of hair (CRM 397), plant mixture (SBMT-02), and soil (SRM 2709). Hydrochemical and biochemical analyses were performed with the help of the known methods (Kraynov and Shvets 1992; Burtis et al. 2006).

Results and discussion

The study showed that activity of the Misur Mining Combine and its Ardon-Khost tailings caused a significant local increase of Pb, Cd, Cu, and Zn content in soils, water, and biotic components as compared to the background values. The mudflow of 2002 changed the structure of landscapes and was followed by a considerable transformation of chemical composition of the downstream river waters and floodplain soils, and by invasion of particular hydrophyte species. Algae and amphibian adapted to the changed conditions and indicated both natural and anthropogenic transformation of the environment. A distinct relation between the particle size of the suspended matter in the Ardon River waters and water salinity was discovered.

Conclusions

Therefore, the Unal basin presents a vivid example of modern natural and anthropogenic evolution of Pb-Zn biogeochemical province under conditions of the extreme and dynamic geochemical environment leading to enhanced risks of ecological damage. Algae species demonstrated high adaptive and indicative capacity in case of both the fast natural and man-made impact.

     

白杨细胞质遗传的细胞学机理(Ⅱ)——质体和线粒体在生殖细胞和营养细胞中的分布与变化

应用电子显微技术,观察白杨派树种毛白杨、毛新杨、银腺杨、中国山扬花粉发育中质体和线粒体在生殖细胞、营养细胞中的分布与变化.结果表明:在小孢子第1次有丝分裂时质体由于极性分布,导致早期生殖细胞的细胞质内缺少质体,为白杨派树种质体母系遗传提供了确切的细胞学证据;线粒体在花粉发育过程中一直存在.同时,细胞学观察发现银腺杨少数...     

银杏小孢子叶球蛋白提取和双向电泳体系优化(Ⅱ)

以银杏小孢子叶球为材料,比较了不同的提取的方法、蛋白质裂解液组成、pH值范围以及不同质量浓度SDS-PAGE凝胶对双向电泳的影响.结果表明:TCA/丙酮/酚法比TCA/丙酮法更适合于银杏小孢子叶球蛋白的提取;含有硫脲的蛋白质裂解液Ⅱ,可显著提高蛋白质的溶解性,在2-DE图谱上可分辨出748个蛋白质点,比用蛋白质裂解液Ⅰ...     

Isotope Oxygen-18 as Natural Tracer of Water Movement in a Coarse Gravel Unsaturated Zone

Water, Air, & Soil Pollution - In the present work, rapid test methods for field screening of soil for Cu, Ni, and Pb content are presented. They are based on commercially obtainable Microquant...