Single and Joint Toxicity of Sulfamonomethoxine and Cadmium on Three Agricultural Crops

In order to evaluate ecological risk of agrochemicals in an agricultural environment, single and joint toxic effects of sulfamonomethoxine (SMM) and cadmium (Cd) on seed germination of wheat (Triticum aestivum L.), Chinese cabbage (Solanum lycopersicum), and radish (Raphanus sativus L.) were investigated. The results showed that the root and shoot elongation were significantly affected under the contamination condition (P < 0.05). In the single-factor experiments, the toxic effect of SMM on crops was much stronger than that of Cd. In the joint effects of SMM and Cd, the interactive effects of the two pollutants on root/shoot elongation of the three crops were complicated, while SMM and Cd had significantly (P < 0.05) synergic effects on root/shoot elongation of the three crops. At the low concentration of SMM, SMM and Cd had significantly (P < 0.05) synergic effects on root/shoot elongation of the three crops, but antagonistic effects were found when the concentration of SMM was high.     

藏北高寒草地土壤有机质化学组成对土壤蛋白酶和脲酶活性的影响

土壤酶作为生态系统的生物催化剂, 是土壤有机体的代谢驱动力, 在土壤物质循环和能量转化过程中起着重要作用。该研究以藏北5种不同类型高寒草地(高寒草甸、高寒草原、高寒草甸草原、高寒荒漠草原和高寒荒漠)为研究对象, 利用热裂解气质联用技术(Py-GC/MS)分析不同类型草地土壤有机质化学组成, 并建立其与土壤蛋白酶和脲酶活性之间的相互关系。结果表明, 5种高寒草地土壤(0-15 cm)的酶活性表现出一定差异性, 高寒荒漠草原土壤的脲酶活性显著高于蛋白酶活性, 而其余类型高寒草地的脲酶和蛋白酶活性之间的差异未达到显著水平; 蛋白酶活性在5种高寒草地土壤之间的差异显著, 而脲酶活性在5种草地土壤之间的差异未达到显著水平。相关分析发现, 土壤蛋白酶活性与土壤有机质烷烃、烯烃和芳香烃的相对丰度和糠醛:吡咯的值密切相关, 土壤脲酶活性与土壤有机质化学组成之间相关性未达到显著水平。综上所述, 高寒草地类型和土壤有机质化学组成是影响高寒草地土壤蛋白酶活性的重要因素, 而对土壤脲酶活性的影响均未达到显著水平, 其影响因素有待进一步深入的研究。     

Seedling recruitment in response to artificial gaps: predicting the ecological consequence of forest disturbance

Plant Ecology - Artificial gaps are widely created for forest management. However, the interactive effects of gap sizes and within-gap locations on seedling regeneration are rarely tested....     

泡桐维管形成层及木质部区的转录组分析

采用Illumina HiSeqTM2500高通量测序技术,获得泡桐维管形成层及木质部区组织转录组的109021918条clean reads(16.35 Gb)。将clean reads从头组装得到104432个单基因簇(Unigene),平均长度662 nt。将组装得到的Unigenes与公共数据库进行序列比对,分别有40789(Nr:39.05%)、31675(NT:30.33%)、15539(COG:14.87%)、29168(GO:27.93%)、16316(KEGG:15.62%)、30499(SwissProt:29.20%)以及28828(Pfam:27.6%)个Unigenes获得功能注释。通过与GO数据库的比对分析,注释的29168个Unigenes归于生物过程、细胞组分及分子功能三大类的55个功能组;15539条Unigenes注释到COG数据库,被分为25个类别中;基于KEGG数据库可将16316个Unigenes归于130个代谢途径。此外,在泡桐的维管形成层及木质部区转录组中共检测出16118个简单序列重复(SSR)位点。为进一步挖掘泡桐重要功能基因提供了大量数据。     

拮抗棉花枯萎病菌的地黄内生细菌筛选、鉴定和促生潜能

【目的】为了筛选棉花枯萎病菌拮抗性菌株资源,从药用植物地黄根块中分离内生细菌,分析优良菌株的促植物生长特性和耐盐碱特性,发掘优良菌株资源,为研发棉花枯萎病生防菌剂提供参考价值。【方法】采用平板对峙法对分离内生细菌进行棉花枯萎病菌拮抗性试验,荧光显微镜观察法研究病原菌菌丝的变化、分光光度计法测定吲哚乙酸(IAA)含量和1-氨基环丙烷-1-羧酸(ACC)脱氨酶活性、平板培养法测定溶磷特性、分隔培养法测定产生挥发性物质抑菌性、比浊法测定内生菌的耐盐碱特性、通过测定代表菌株理化特性、16S rDNA序列并分析系统发育地位、盆栽接种试验验证防病效果。【结果】地黄内生细菌对棉花枯萎病菌具有拮抗性,其中菌株DH9、DH66、DH92拮抗作用较强。与对照组菌丝对比,处理组菌丝出现打结、弯曲和断裂现象,菌丝末端分枝明显增多,多数边缘菌丝呈珊瑚状分枝,存在明显被菌体包埋等现象。菌株DH83、DH66、DH92、DH9、DH56产生挥发性物质对棉花枯萎病菌均有抑制作用,但抑制效果不明显。产生IAA含量均大于1.32 mg/L的有7株(DH92、DH30、DH71、DH83、DH93、DH9、DH56),其中DH92产量最高,为34.696mg/L。菌株DH92和DH30产生ACC脱氨酶活力分别为118.612μmol/(mg·h)和103.795μmol/(mg·h)。菌株DH92无机磷溶磷能力最强,溶磷圈直径/菌落直径(D/d)为1.51;菌株DH71溶解有机磷能力最强,D/d为4.50。菌株DH9和DH56分别能够耐受在7%、3%NaCl盐浓度,在pH 8–10均能生长,具有一定耐盐碱性。结合菌株培养特征、生理生化特性和16S rDNA测序及系统发育分析,结果表明DH30最相似菌株为沙福芽孢杆菌(Bacillus safensis),DH9最相似菌株为枯草芽孢杆菌(Bacillussubtilis),DH92最相似菌株为菠萝泛菌(Pantoea ananatis)。DH92处理组防治效果达77.29%,其他防效在63%以上,可作为棉花枯萎病的生防菌株资源。【结论】药用植物地黄根块中存在棉花枯萎病菌拮抗性菌株资源,其中菠萝泛菌DH92从地黄根块中分离未曾见报道。优良地黄内生细菌具有促进植物生长特性和一定耐盐碱性,为防治棉花枯萎病和研发生物防治菌剂提供了基础。     

Sinanaerobacter chloroacetimidivorans gen. nov., sp. nov., an obligate anaerobic bacterium isolated from anaerobic sludge

An obligate anaerobic bacterial strain (BAD-6^T) capable of degrading acetochlor and butachlor was isolated from an anaerobic acetochlor-degrading reactor. Cells were Gram-stain positive, straight to gently curved rods with flagella. The major fermentation products in peptone-yeast broth were acetate and butyrate. The optimum temperature and pH for growth was 30 °C and 7.2–7.5, respectively. The major cellular fatty acids (>?10%) were C_14:0 FAME, C_16:0 FAME and cyc-9,10-C_19:0 DMA. Genome sequencing revealed a genome size of 4.80 Mb, a G?+?C content of 43.6 mol% and 4741 protein-coding genes. The most closely related described species on the basis of 16S rRNA gene sequences was Anaerovorax odorimutans NorPut^T in the order Clostridiales of the class Clostridia with sequence similarity of 94.9%. The nucleotide identity (ANI) value and digital DNA–DNA hybridization (dDDH) between the genomes of strain BAD-6^T and Ana. odorimutans NorPut^T were 70.9% and 15.9%, respectively. Based on the distinct differences in phylogenetic and phenotypic characteristics between strain BAD-6^T and related species, Sinanaerobacter chloroacetimidivorans gen. nov., sp. nov. is proposed to accommodate the strain. Strain BAD-6^T is the type strain (=?CCTCC AB 2021092^T?=?KCTC 25290^T).

     

The histology and ultrastructure of the salivary glands of Neopanorpa longiprocessa (Mecoptera: Panorpidae)

The salivary glands of Panorpidae usually exhibit distinct sexual dimorphism and are closely related to the nuptial feeding behavior. In this study, the salivary glands of Neopanorpa longiprocessa were investigated using light microscopy and transmission electron microscopy. The salivary glands are tubular labial glands and consist of a scoop-shaped salivary pump, a common salivary duct, and a pair of salivary tubes. The male and female salivary glands are remarkably different in the bifurcation position of the common salivary duct and the length and shape of the secretory tubes. Compared with the simple female salivary glands, the male’s are more developed as their paired elongated salivary tubes can be divided into two parts, the glabrate anterior tube and the posterior tube with many secretory tubules. The ultrastructural study shows that the male salivary tubes have strong secretory function. The existence of different secretion granules indicates that there are some chemical reactions or mixing occurring in the lumen. Based on the ultrastructural characteristics, the functions of the different regions of the salivary tube have been speculated. The relationship between the salivary glands and nuptial feeding behavior of N. longiprocessa has been briefly discussed based on the structure of the salivary glands.

     

Changes of alkaline phosphatase activity in response to different stressors in planarian Dugesia japonica

The aims of this work are to provide some properties of alkaline phosphatase (ALP) in the planarian Dugesia japonica and detect its activity in response to different stressors, as well as to introduce renatured SDS-PAGE to study enzyme activity in planarians. Our results indicate that ALPs in planarians are mainly membrane-bound form, identified as three mainly enzyme-bands (approximately MW 260 kD, 180 kD, 160 kD, respectively). Under our experimental conditions, ALPs activity had no apparent changes in response to low concentration of Hg²⁺ (25 μg L^?1) and Pb²⁺ (125 μg L^?1, 250 μg L^?1) exposure, but were severely inhibited in response to high concentration of Hg²⁺ (50 μg L^?1, 150 μg L^?1, 300 μg L^?1) and Pb²⁺ (500 μg L^?1, 1000 μg L^?1) exposure. Mild heat shock (25°C for 2 days) elevated ALP activity, but severely heat shock (25°C for 2 days, followed by 30°C for 2 days and 32°C for 2 days) inactivated ALP activity. Interestingly, ALP and other cytosolic phosphatases (MW from ～45 kD to ～60 kD) activity increased noticeably during the early stage of planarians regeneration, which may be involved in cell proliferation and differentiation. Contrary to regeneration, prolonged starvation suppressed ALP activity. The above findings provide valuable information about the role of ALP in planarian regeneration and for its use as an indicator in ecotoxicology.