Effect of apple cultivars and storage periods on the virulence of Neofabraea spp.

Bull’s eye rot is a typical quiescent postharvest apple disease in major fruit-growing areas. The susceptibility of different apple cultivars to Neofabraea spp. (N. vagabunda and N. malicorticis) was assessed, with Granny Smith showing the most resistance and Cripps Pink the most susceptibility. To assess the factors involved in conidial germination, Neofabraea spp. were grown on crude protein extracts (CPEs) collected from apple fruits at different storage periods. Fungal germ tube growth rate and pathogenic enzyme (cellulase and xylanase) activity were assessed. Results showed that CPEs collected after 2 and 4 months of storage progressively stimulated conidial germination and germ tube elongation, while a lesser effect was observed from CPEs after 1 month of storage. Xylanase proved to be the main degrading enzyme secreted by all the isolates, while cellulase was produced only by N. vagabunda isolates. Overall, the isolate ID02 was the most virulent, based on more rapid germ tube elongation and greater activity of the lytic enzymes.     

黏虫蛹性别的快速鉴别方法

根据黏虫Mythimna separata(Walker)蛹生殖孔的位置、腹部腹节的外部形态学特征、生殖孔(产卵孔)至排泄孔之间的距离,快速、准确鉴别黏虫蛹性别。雌蛹第8腹节腹面中央的生殖孔与第9腹节的产卵孔连接形成一纵裂缝,裂缝两侧平坦,无突起。生殖孔下端与第9腹节的前缘连接、产卵孔下端与第10腹节的前缘连接,形成2个明显的"人"字纹。雄蛹第8腹节无纵裂缝,在第9腹节腹面中央的生殖孔呈现的纵裂缝连接第10腹节,裂缝两边各有一个半圆形瘤状突起。雌雄蛹排泄孔均在第10腹节腹面,雌蛹产卵孔下端至排泄孔上端之间的距离为(400.85±151.10)μm,雄蛹生殖孔下端至排泄孔上端之间的距离为(178.21±93.59)μm,约为雌蛹相应距离的一半。采用该方法观察的270头羽化蛹的性别鉴别准确率100%。该方法对于快速鉴别黏虫蛹的性别、开展黏虫相关的生物学研究以及预测预报等具有重要的参考价值。     

起垄沟播和常规平播下滴灌棉田土壤水盐的运移

为明确滴灌条件下植棉方式对土壤水盐运移的影响,采用田间调查与室内分析相结合的方法,在滨海重度盐碱地开展了起垄沟播和常规平播植棉方式下的水盐运移试验,调查了滴灌前后两种植棉方式不同点位及不同土壤深度的土壤水分、盐分和土壤溶液电导率等指标,分析不同植棉方式土壤水分、盐分和土壤溶液电导率的时空分布特征。结果表明：滴灌条件下起垄沟播的水分入渗深度和盐分淋洗深度均明显大于常规平播植棉方式,起垄沟播植棉膜下(0~20 cm)土壤溶液电导率明显低于常规平播植棉;滴灌对两种种植方式膜外土壤水分和盐分运移未产生明显影响。起垄沟播联合滴灌技术更有利于为棉花生长的水盐环境。研究结果可为盐碱地植棉提供理论参考和实践依据。     

蔬菜中13种有机磷农药基质效应研究

有机磷农药在农业生产中广泛应用,用气相色谱法进行农药残留检测容易产生基质效应,影响分析结果的可靠性,为研究用气相色谱法进行农残检测过程中有机磷农药在不同蔬菜中的基质效应,选取瓜类、茄果类、叶菜类3类常见蔬菜和13种有机磷农药进行研究,对影响基质效应的因素采取不同变量法进行分析,得出结论:有机磷农药在叶菜类蔬菜中基质效应最大;含有P=O键农药基质效应更强;基质含量越多基质效应越强,并对在检测如何减少基质效应给出了建议.     

低温等离子体耦合Fe2O3催化剂去除粮食仓储环境中磷化氢

为了探究低温等离子体（Non-Thermal Plasma,NTP）耦合催化剂对粮仓中磷化氢（PH3）的去除效果,该文采用介质阻挡放电低温等离子体与催化剂耦合的反应装置,研究了NTP与Fe2O3催化剂耦合对PH3去除率的影响,并对耦合反应后的催化剂进行表征,分析产物及反应机理。结果表明,载体和催化剂与NTP耦合改变了NTP的放电状态,提高了PH3去除率;不同载体负载Fe2O3后,在输入功率超过53 W时,NTP与Fe2O3催化剂耦合对PH3去除率均高于无填充,Fe2O3/Al2O3与NTP耦合效果最好,去除效率达到了100%。耦合前后催化剂的表征结果表明,耦合反应之后,Fe2O3/Al2O3催化剂的比表面积降低了11.23%,Fe3+/(Fe2++Fe3+)含量提高了21.06%,Osur/(Olatt+Osur+Oads)含量减少了2.24%,Fe含量降低了4.69%,P含量增加了4.34倍。产物分析表明耦合后生成的主要产物为磷酸。研究结果表明NTP耦合Fe2O3/Al2O3催化剂具有很好的PH3去除效果,为粮食仓储行业去除磷化氢提供理论依据。     

基于稳定同位素特征与土壤性质的有机茶身份辨识研究

为探究云南普洱地区有机茶身份辨识特征,完善高原有机茶身份辨识技术,选取云南省普洱市的5个代表性有机种植认证茶园（ZX、LS、CYT、YS、HL）和相邻的5个常规茶园（C-1、C-2、C-3、C-4、C-5）,采集300余份茶叶和土壤样本,结合稳定同位素比例质谱仪、元素分析仪等测定茶叶和土壤的δ¹⁵N丰度、δ¹³C丰度、全氮、全碳、有机碳、碱解氮等指标,通过因子分析和判别分析的方法构建了有机茶叶同位素-土壤性质判别模型,并使用Holdout法进行验证。结果表明：不同茶园有机茶叶与相邻常规茶叶相比未表现出一致的δ¹⁵N,δ¹³C值差异规律,因此,使用单一稳定同位素因子难以鉴别有机茶。通过进一步对茶叶和土壤性质进行因子分析,筛选出6个适合判别的特征向量,构建了基于同位素特征和土壤性质的多元有机判别模型,其判别函数方程为：y=-0.081（茶叶δ¹⁵N）＋0.819（茶叶δ¹³C）＋0.093（土壤全氮）＋2.117（土壤全碳）－0.155（土壤有机碳）＋2.870（土壤pH）＋4.232,y<0.5为常规茶,判别准确度为92.3%。综上,基于同位素特征值和土壤性质参数指标构建的多元有机判别模型可实现云南省普洱市高原有机茶身份的准确判别。     

Assessing spillover from marine protected areas and its drivers: A meta‐analytical approach

Overfishing may seriously impact fish populations and ecosystems. Marine protected areas (MPAs) are key tools for biodiversity conservation and fisheries management, yet the fisheries benefits remain debateable. Many MPAs include a fully protected area (FPA), restricting all activities, within a partially protected area (PPA) where potentially sustainable activities are permitted. An effective tool for biodiversity conservation, FPAs, can sustain local fisheries via spillover, that is the outward export of individuals from FPAs. Spillover refers to both: “ecological spillover”: outward net emigration of juveniles, subadults and/or adults from the FPA; and “fishery spillover”: the fraction of ecological spillover that directly benefits fishery yields and revenues through fishable biomass. Yet, how common is spillover remains controversial. We present a meta‐analysis of a unique global database covering 23 FPAs worldwide, using published literature and purposely collected field data, to assess the capacity of FPAs to export biomass and whether this response was mediated by specific FPA features (e.g. size, age) or species characteristics (e.g. mobility, economic value). Results show fish biomass and abundance outside FPAs was higher: (a) in locations close to FPA borders (<200 m) than further away (>200 m); (b) for species with a high commercial value; and (c) in the presence of PPA surrounding the FPA. Spillover was slightly higher in FPAs that were larger and older and for more mobile species. Based on the broadest data set compiled to date on marine species ecological spillover beyond FPAs' borders, our work highlights elements that could guide strategies to enhance local fishery management using MPAs.     

黄颡鱼人工繁殖的几个关键问题

近年来,随着黄颡鱼养殖的不断发展,黄颡鱼苗种的供应日趋紧张.为了解决和突破这一制约黄颡鱼养殖的"瓶颈"问题,生产更多更优质的黄颡鱼苗种,保证黄颡鱼养殖稳步而快速的发展,对黄颡鱼的人工催产繁殖各地都做了大量的研究工作.     

鱼源嗜水气单胞菌多重耐药菌株整合子的分子特征

为研究嗜水气单胞菌多重耐药菌株整合子-基因盒分布及分子特征, 首先采用K-B纸片扩散法检测28株鱼源嗜水气单胞菌对18种抗生素的耐药性, 然后利用PCR方法检测菌株中Ⅰ、Ⅱ、Ⅲ型整合酶基因并对其携带基因盒序列进行分析。结果表明, 分离到的鱼源嗜水气单胞菌呈多重耐药性, 对b-内酰胺类、大环内酯类、氯霉素类和四环素类药物的耐药率超过60%, 而对氟喹诺酮类药物较敏感, 且菌株间耐药谱差异较大。53.57%的菌株Ⅰ类整合子阳性, 21.43%的菌株Ⅱ类整合子阳性, 整合子阳性菌株对多种药物的耐药率均高于阴性株, 且Ⅰ类整合子阳性株多重耐药率明显高于Ⅱ类整合子阳性株, 表明整合子系统在嗜水气单胞菌多重耐药性中发挥重要作用。Ⅰ类整合子基因盒以aadA、dfrA、catB家族为主, 分别介导氨基糖苷类、甲氧磺胺嘧啶类和氯霉素类药物耐药; 基因盒的排列以aadA2+dfrA12类型为主。此外, Ⅰ类整合子阳性的嗜水气单胞菌多重耐药性在不同个体间也存在较大差异, 提示多重耐药菌株的耐药表型与基因盒的类型无直接相关性。

     

Putative virulence-related genes in Vibrio anguillarum identified by random genome sequencing

The genome of Vibrio anguillarum strain H775-3 was partially determined by a random sequencing procedure. A total of 2,300 clones, 2,100 from a plasmid library and 200 from a cosmid library, were sequenced and subjected to homology search by the BLAST algorithm. The total length of the sequenced clones is 1.5 Mbp. The nucleotide sequences were classified into 17 broad functional categories. Forty putative virulence-related genes were identified, 36 of which are novel in V. anguillarum, including a repeat in toxin gene cluster, haemolysin genes, enterobactin gene, protease genes, lipopolysaccharide biosynthesis genes, capsule biosynthesis gene, flagellar genes and pilus genes.