Seed dispersal and seedling emergence in an old field community in central New York (USA)

Summary Seed dispersal and seedling emergence of common taxa growing in a Solidago-dominated old field in central New York (USA) were monitored from May 1982 to June 1984. Over 3.5x10⁴ seeds per m² were captured on seed traps in each of the two years, with peaks occuring in July (due to Hieracium) and in November (due to Solidago). About 4.0x10³ seedling/m² emerged beneath the intact community in each of the two years. Although seedlings emerged predominantly in the early spring, a secondary peak occurred in September and October when many seedlings of introduced grasses appeared. Two additional aspects of the reproductive biology of the major taxa were related to the seasonal timing of seed dispersal: As the date of peak seed dispersal (among taxa) became progressively later in the season, (1) the duration of dispersal increased from about one week to about one-half year, and (2) the delay between the peak of seed dispersal and the peak of seedling emergence increased from a few days to about one-half year.     

竹荪的菌丝培养及其抗菌性的初步研究

对长裙竹荪（Ｄｉｃｔｙｏｐｈｏｒａ　ｉｎｄｕｓｉａｔａ）等３种的菌丝培养进行了研究并初步测定菌丝的抗菌谱。培养液的 ｐＨ和液体培养基粘度是竹荪在液体中生长的关键因素,在 ｐＨ４.７和添加 ０.５％ＣＭＣ－Ｎａ的合适培养条件下竹荪菌丝在液体中能够生长,菌丝得率达到１％。还探讨了其他几种竹荪菌丝的培养方法,为竹荪菌丝的大量生产提供了依据。另外,在竹荪抗菌性实验中发现,竹荪对许多易造成食品腐败的细菌和酵母具有抗性,但没有发现其对霉菌有抗性。     

新烟碱类和大环内酯类杀虫剂对四种赤眼蜂成蜂急性毒性和安全性评价

为了明确新烟碱类和大环内酯类杀虫剂对天敌赤眼蜂Trichogramma spp.的影响, 在室内采用药膜法测定了其对稻螟赤眼蜂Trichogramma japonicum Ashmead、 亚洲玉米螟赤眼蜂Trichogramma ostriniae Pang et Chen、 拟澳洲赤眼蜂Trichogramma confusum Viggiani和广赤眼蜂Trichogramma evanescens Westwood成蜂的急性毒性, 并进行了安全性评价。急性毒性测定结果表明： 在测定的新烟碱类药剂中, 噻虫嗪对拟澳洲赤眼蜂和稻螟赤眼蜂表现出最高的急性毒性, 其LC₅₀分别为0.24 (0.21~0.27) 和0.40 (0.37~0.44) mg a.i./L; 其次为烯啶虫胺, 该药剂对上述两种赤眼蜂的LC₅₀分别为0.83 (0.74~0.96) 和0.72 (0.65~0.80) mg a.i./L; 而吡虫啉对亚洲玉米螟赤眼蜂和拟澳洲赤眼蜂的毒性最低, 其LC₅₀分别为502.13 (459.80~549.62)和752.62 (687.51~828.63) mg a.i./L。在测定的大环内酯类药剂中, 阿维菌素对稻螟赤眼蜂的急性毒性最高, 其LC₅₀为0.49 (0.46~0.65) mg a.i./L, 而甲氨基阿维菌素苯甲酸盐对拟澳洲赤眼蜂表现出最低的急性毒性, 其LC₅₀为21.76 (19.59~24.40) mg a.i./L。安全性评价结果表明, 吡虫啉、 啶虫脒、 氯噻啉和甲氨基阿维菌素苯甲酸盐对4种赤眼蜂为低风险~中等风险性, 安全性系数为0.57~23.54; 噻虫啉和依维菌素对4种赤眼蜂却为中等风险~高风险性, 安全性系数为0.16~3.45; 而烯啶虫胺、 噻虫嗪和阿维菌素对4种赤眼蜂为高风险~极高风险性, 安全性系数为0.01~0.15。本研究测定的大部分杀虫剂对赤眼蜂都有一定的急性毒性风险。因此, 在害虫综合治理中应谨慎使用新烟碱类和大环内酯类杀虫剂尤其是烯啶虫胺、 噻虫嗪和阿维菌素, 以免造成对赤眼蜂的大量杀伤。     

植物激素对砀山酥梨脱病毒苗增殖生长的影响

砀山酥梨脱病毒苗培养基中添加外源激素能通过调节内源激素的含量,从而控制脱病毒苗的增殖和生长。苄基腺嘌呤(benzyladen ine,BA)处理可提高脱病毒苗内源玉米素核苷(zeatin riboside,ZR)含量,而脱病毒苗的有效增殖芽数与IAA/ZR比值呈显著负相关;1萘-乙酸(1-naphthalene acetic ac id,NAA)处理可显著提高内源吲哚乙酸(indole acetic ac id,IAA)含量,较高的内源IAA含量有利于芽梢的生长;继代组培苗体内含有一定量的内源赤霉素(G iberllic Ac id,GA1 3),适量的外源GA3处理,可提高内源GA1 3含量而显著降低脱落酸(absc isic ac id,ABA)含量,促进芽梢的伸长和叶面积的扩大。     

Detection of Nitrosomonas spp. by polymerase chain reaction

Abstract A unique genomic DNA fragment was isolated from Nitrosomonas europaea ATCC 19718. Based on the sequence of this fragment, oligonucleotide primers for polymerase chain reaction amplification were prepared which amplify sequences of 775 and 658 bp. The predicted DNA fragments were both amplified from the genome of N. europaea and a Nitrosomonas spp. isolated from a local oxidation pond. The primers failed to amplify DNA from the genomes of the ammonia oxidiser Nitrosolobous multiformis , the nitrite oxidiser Nitrococcus mobilis as well as from the genomes of other unrelated heterotrophic bacteria. These DNA sequences could be amplified from 0.01 ng of N. europaea genomic DNA or from 100 intact cells, and it was possible to detect Nitrosomonas DNA in a DNA mixture extracted from water samples drawn from a local oxidation pond.     

Analysis of the molecular mass heterogeneity of the transferrin receptor in Neisseria meningitidis and commensal Neisseria

Peroxidase-conjugated transferrin was used to detect transferrin receptors both in intact outer membrane vesicles (OMVs) from Neisseria species in a dot blot assay, and in SDS-PAGE-separated OMV proteins after transferring to nitrocellulose membranes. All N. meningitidis strains produced transferrin receptors after culturing in either iron sufficiency or iron restriction although expression was higher in the latter case, whereas only six N. lactamica and two N. sicca (among 20 commensal species) were able to bind transferrin. Molecular mass (MM) of the receptors were mainly between 78 kDa and 85 kDa (87.5% of strains), 12.5% had receptors with MM close to 70 kDa, and 5% showed receptors with MM over 85 kDa. Our results confirm the molecular mass heterogeneity of the transferrin receptors in N. meningitidis, completely disagree with the 'universal' 98 kDa receptor proposed by some authors, and show a low expression of the receptor in commensal Neisseria.     

沙门氏菌荧光实时定量PCR检测试剂的研制及应用

荧光实时定量PCR技术是近年来广泛应用于沙门氏菌快速检测的现代方法之一,本研究建立了检测沙门氏菌快速、敏感、特异以及准确定量的FQ-PCR方法。采用沙门氏菌fimY基因序列,设计特异引物和探针,通过对Taq酶、Mg2 和引物探针浓度等反应体系和条件的优化,然后进行特异性和适用性实验。最优化结果为:Taq酶用量2.5U;Mg2 浓度为3.75×10-3mol/L;引物浓度为0.65×10-6mol/L,探针浓度为0.30×10-6mol/L;循环条件为step1:95℃2min,step2:95℃5s,60℃40s,40cycles。结果表明该FQ-PCR检测试剂具有快速、简单、灵敏度高、特异性强和适用范围广等优点,可应用于食品卫生监管、商品检验检疫以及临床诊断等领域。     

驱除侵袭大质粒pINV对福氏2a志贺氏杆菌2457T影响的比较蛋白质组学研究

将福氏志贺氏杆菌2a 2457T及其驱除侵袭大质粒pINV的菌株培养至对数生长中期,制备了全细胞蛋白质。用双向电泳分离两种细胞蛋白质混合物并进行比较,找出差异点,这些点经过胶内酶切后进行MALDI_TOF质谱鉴定。每个蛋白质点的肽指纹图谱都在福氏志贺氏杆菌2a 2457T株的蛋白质数据库用Mascot进行检索,共发现了10个差异表达的蛋白质。结果显示驱除大质粒后几个参与核酸代谢途径的酶表达量有所上升。其中胞啶/脱氧胞啶脱氨酶、嘌呤核苷磷酸化酶和尿嘧啶核苷磷酸化酶表达量的上升可能造成尿嘧啶和尿（嘧啶核）苷合成的增加。     

Movements of beluga whales (Delphinapterus leucas) in Bristol Bay,Alaska

We describe the annual distribution of beluga whales (Delphinapterus leucas) in Bristol Bay, Alaska, using data from 31 satellite‐linked transmitters during 2002–2011. Bristol Bay has one of the largest and best studied Pacific salmon (Oncorhynchus spp.) fisheries in the world, allowing us to link the seasonal distribution of belugas to that of salmon. During salmon migrations, beluga movements were restricted to river entrances. Belugas generally did not relocate to different river entrances or change bays during peak salmon periods. However, the location of belugas was not related to the number of salmon passing counting towers, suggesting that belugas were either selecting locations that were good for catching salmon or there were simply more salmon than belugas needed to supply their nutritional needs. The distribution of belugas expanded after salmon runs ended, and was greatest in winter when belugas ranged beyond the inner bays, traveling as far west as Cape Constantine. Belugas continued to frequent the inner bays in winter whenever sea ice conditions allowed, e.g., when winds moved sea ice offshore; however, they were never located south of the southern ice edge in open water or outside of Bristol Bay.     

不同品种黑莓鲜果营养成分的比较

对5个黑莓(Rubusspp.)新品种鲜果的营养成分进行了比较分析。结果显示,5个品种黑莓鲜果的糖酸比较低,为3.11~6.18,风味偏酸。VC含量较高,达0.064~0.566 mg.g-1;VE含量为0.013~0.049 mg.g-1,品种间差异较大,以品种‘Triple Crown’的VE含量最高。矿质元素含量较高,其中品种‘Boysen’的Se含量最高,是其他品种的6~13倍;品种‘Young’的K、Ca、Zn和Fe含量都较高。黑莓鲜果含有8种人体必需氨基酸,不同品种黑莓鲜果的总氨基酸含量差异较大,其中品种‘Brazos’的总氨基酸含量最高,可达15.21 mg.g-1。