Effects of imazethapyr spraying on plant growth and leaf surface microbial communities in Arabidopsis thaliana

Imazethapyr (IM) is an acetolactate synthase (ALS)-inhibiting herbicide that has been widely used in recent years. However, IM spraying can lead to the accumulation of herbicide residues in leaves. Here, we determined the effects of IM spraying on the plant growth and leaf surface microbial communities of Arabidopsis thaliana after 7 and 14?days of exposure. The results suggested that IM spraying inhibited plant growth. Fresh weight decreased to 48% and 26% of the control value after 7 and 14?days, respectively, of 0.035?kg/ha IM exposure. In addition, anthocyanin content increased 9.2-fold and 37.2-fold relative to the control content after 7 and 14?days of treatment, respectively. Furthermore, IM spraying destroyed the cell structures of the leaves, as evidenced by increases in the number of starch granules and the stomatal closure rate. Reductions in photosynthetic efficiency and antioxidant enzyme activity were observed after IM spraying, especially after 14?days of exposure. The diversity and evenness of the leaf microbiota were not affected by IM treatment, but the composition of community structure at the genus level was altered by IM spraying. Imazethapyr application increased the abundance of Pseudomonas, a genus that includes species pathogenic to plants and humans, indicating that IM potentially increased the abundance of pathogenic bacteria on leaves. Our findings increase our understanding of the relationships between herbicide application and the microbial community structures on plant leaves, and they provide a new perspective for studying the ecological safety of herbicide usage.     

Coupled biodegradation of p-nitrophenol and p-aminophenol in bioelectrochemical system: Mechanism and microbial functional diversity

Biodegradation mechanisms and microbial functional diversity during coupled p-nitrophenol (PNP) and p-aminophenol (PAP) degradation were studied in a bioelectrochemical system. PNP in the biocathode and PAP in the bioanode were almost completely removed within 28hr and 68hr respectively. The degradation followed the steps including hydrating hydroxyalkylation, dehydrogenating carbonylation, and hydrolating ring cleavage, etc. Metagemomic analysis based on the KEGG and eggNOG database annotations revealed the microbial composition and functional genes/enzymes related to phenol degradation in the system. The predominant bacteria genera were Lautropia, Pandoraea, Thiobacillus, Ignavibacterium, Truepera and Hyphomicrobium. The recognized biodegradation genes/enzymes related to pollutant degradation were as follows: pmo, hbd, & ppo for phenol degradation, nzba, amie, & badh for aromatic degradation, and CYP & p450 for xenobiotics degradation, etc. The co-occurrence of ARGs (antibiotic resistant genes), such as adeF, MexJ, ErmF, PDC-93 and Escherichia_coli_mdfA, etc., were annotated in CARD database during the biodegradation process. The Proteobacteria & Actinobacteria phylum was the primary host of both the biodegradation genes & ARGs in this system. The microbial functional diversity ensured the effective biodegradation of the phenol pollutants in the bioelectrochemical system.     

聚丙烯微塑料对污泥厌氧消化效能作用影响

以聚丙烯（PP）微塑料为研究对象,考察不同浓度PP微塑料对污泥厌氧消化产CH₄和产酸效能的作用影响,同时采用荧光定量PCR方法定量检测了乙酸激酶（AK）和mcrA基因在不同PP微塑料作用下的丰度变化.结果表明,PP微塑料对污泥厌氧消化产CH₄和产酸效能具有促进影响,CH₄和乙酸累计产量随PP微塑料投加量的增大而升高,当PP微塑料投加量为0.2g/g VSS时,CH₄和乙酸累计产量与空白对照相比分别提高148.2%和15.2%,达227.1mL/g VSS和1291.2mg/L.相应地,mcrA基因丰度随之提高98.2%,表明PP微塑料对产甲烷菌的生长和繁殖具有促进作用,进而强化污泥厌氧消化产CH₄效能.     

广东省蛭态轮虫物种多样性及其系统发育研究

为了解广东省蛭态轮虫物种多样性,采集广东省不同水陆生境样品98份,记录蛭态轮虫3目4科12属66种（含亚种）.陆生环境中鉴定出蛭态轮虫56种,其中苔藓生境42种、落叶生境40种、地衣生境12种,水生生境蛭态轮虫15种,陆生生境的蛭态轮虫种类明显多于水生生境蛭态轮虫.为验证形态鉴定的准确性,获取蛭态轮虫COⅠ基因序列4属16种37条,种间遗传距离8.59%~23.17%,其中楔足盘网轮虫（Adineta cuneata）和迅捷旋轮虫（Philodina rapida）的COⅠ基因序列为全球首次报道.COI基因序列中腺嘌呤（A）与胸腺嘧啶（T）的总含量（71.2%）远大于鸟嘌呤（G）与胞嘧啶（C）（28.8%）的含量.系统发育树的聚类结果与形态学物种鉴定结果一致;同属形态相近的物种,具有较高的同源性.研究结果表明,形态学鉴定与DNA条形码技术相结合,有助于提高蛭态轮虫种类鉴定的准确性和探究蛭态轮虫各属的发育地位,促进蛭态轮虫物种多样性和生态学研究.     

生物芯片技术及其应用前景

生物芯片技术是一项发展迅速的高新技术，广泛应用于生物、医学、农业、环境检测和食品科学等领域，市场前景十分广阔。阐述了生物芯片的基本概念、分类及其主要应用，并对其发展前景作了展望。     

主基因研究与畜禽遗传资源开发

论述了畜禽主基因的概念、利用价值及研究状况，指出我国畜禽遗传资源的开发，实质上就是要发掘利用特异性状的主基因，并就如何开发利用主基因进行了探讨。     

A simple,rapid, and highly informative PCR-based procedure for prenatal diagnosis and carrier screening of phenylketonuria

The polymorphic information content (PIC) and the degree of heterozygosity of several polymorphic systems within the phenylalanine hydroxylase (PAH) gene were determined in 85 European Caucasian and 19 Chinese phenylketonuria (PKU) kindreds. The first system examined, a short tandem repeat (STR), had a PIC of 80 and 73 per cent in these Caucasian and Chinese samples, respectively. The degree of heterozygosity actually observed for this system was 81 and 64 per cent in the Caucasian and Chinese PKU families, respectively. Through the addition of a second polymorphism based on a variable number of tandem repeats (VNTR), the PIC was increased to 90 per cent in Caucasians, but only to 75 per cent in Chinese. The degree of heterozygosity observed for this combination was 94 per cent in European PKU families and 67 per cent in Chinese PKU families. The further addition of an Xmnl RFLP increased both the PIC and the level of heterozygosity in Caucasians to 95 per cent, but did not change either of these measures in Chinese. The combined use of these three polymorphisms significantly increases the informativity of prenatal diagnostic and carrier screening procedures in both Caucasian and Chinese PKU kindreds. Furthermore, since each of these polymorphisms can be studied by PCR-based methods, these new tests can be performed more quickly and easily than previous Southern-based procedures.     

遗传算法在二氧化硫总量控制中的应用研究

污染物总量控制是目前我国广泛应用的一种控制区域环境质量达标的方法,为了实施城市大气污染物排放总量控制,实现各功能区污染物浓度达标,采用浓度控制与总量控制相结合的方法。本文提出利用遗传算法进行大气污染总量控制,并在传统遗传算法的基础上做了改进,提出基因库和基因重组的方法。     

害虫抗性杂合子死亡率对抗性进化的影响

通过计算机模拟,研究了在R基因频率和种群大小的三种不同组合情况下,害虫抗性杂合于在用药或不用药时对抗性进化的影响.模拟结果表明,1)在任何组合中不用药时R基因的衰退是一个缓慢的过程,除非(RR)和(RS)遗传型的生物适合度很低.若R基因的显性越高,生物适合度越低,则抗性基因衰退越快.2)用杀死全部或绝大多数杂合子的剂量,并有少量敏感个体迁入时,抗性可被控制.但抗性一旦很明显,则此策略不再有效.