西玛津在茶叶及土壤中的残留与安全性评价

为茶叶上安全使用西玛津及制定其最大残留限量(MRL)国家标准提供科学依据,通过田间试验和室内检测,研究西玛津在茶园土壤中的残留消解动态及在茶叶和土壤中的残留特性与安全风险。结果表明:西玛津在土壤中的半衰期为8.7~9.7d,药后30d消解89%以上。地面喷雾50%西玛津可湿性粉剂1 875g a.i./hm~2和2 812.5g a.i./hm~2,施药7d后收获的茶叶中西玛津残留量均低于0.05 mg/kg(MRL)。西玛津在茶叶上的安全间隔期为7d。     

真菌源壳聚糖酶的纯化及其特征

真菌壳聚糖酶类催化水解壳聚糖,它们在自然界的碳氮循环以及用于处理海洋食品和生产药用寡聚壳聚糖等工业上均有非常重要的意义.自1981年来,已有一些真菌源壳聚糖酶获得了纯化、明确了其特性,并作了序列分析.本文从以下3个方面阐述了真菌壳聚糖酶的近期研究进展1)从Aspergillus fumigatus KH-94, Fusarium solani, Mucor rouxii A*B, Penicillum islandicum, P. spinulosum, Rhodotorula gracilis, Trichoderma reesei, A. oryzae, A. fumigatus Y2K 和 A. fumigatus S-26等真菌中获得的胞内壳聚糖酶的纯化及其特性;2)从T. reesei, A. oryzae, A. fumigatus and Cordyceps sp. MET 1504等真菌中获得的胞外壳聚糖酶的纯化及其特性;3)从T. reesei, Metarhizium anisopliae, A. oryzae and A. fumigatus S-26等真菌中获得的壳聚糖酶氨基酸序列的分析.     

甘肃省陇南、天水林区土壤曲霉属种的研究

 对100份来自陇南、天水林区的土样进行曲霉属(Aspergillus Mich. ex Link: Fr.)菌的分离,结合菌落形态及显微镜下孢子的形态将各菌鉴定到种。结果表明:甘肃省陇南、天水林区土壤中分布有6个种和4个变种。分别是烟曲霉原变种(Aspergillus fumigatus var. fumigatus)、烟曲霉椭孢变种(Aspergillus fumigatus var. ellipticus)、土曲霉原变种(Aspergillus terreus)、杂色曲霉原变种(Aspergillus versicolor)、刺孢裸胞壳(Emericella echinulata)、构巢裸胞壳(Emericella nidulans var. nidulans)、褶皱裸胞壳(Emericella rugulosa)、四脊裸胞壳(Emericella quadrilineata)、茴香裸胞壳(Emericella foeniculicola)及矮棒曲霉(Aspergillus cavatonaicus)。     

西安市大田土壤中抗药性烟曲霉发生率调查

为了探究农用三唑类化合物的使用与烟曲霉抗药性之间的潜在联系,研究采集了西安市区周边大田土壤样品36份,其中15份土壤样品中共分离出34株烟曲霉菌株,烟曲霉菌株的分离率为41.7%。34株烟曲霉中有2株（R-5和R-17）表现出三唑类药物的抗药性,抗性菌株占烟曲霉菌株总数的5.9%。经基因测序结果表明菌株R-5其cyp51A基因无点位点突变,R-17菌株cyp51A基因存在TR34/L98H/S297T/F495I型突变。     

菌株XC6的筛选及其对稻草的降解研究

以稻草降解率为指标,以稻草粉为唯一碳源,从霉变的稻草、麦秸、枯枝烂叶等天然纤维素中分离获得一批天然纤维素降解菌,并从中筛选出1株对稻草降解能力较强的真菌.根据对其形态鉴定和18S rDNA序列分析发现,该菌株与烟曲霉(Aspergillus fumigatus)的同源性为100%, 将该菌株命名为XC6.XC6对稻草纤维素、半纤维素及稻草总降解率分别为72%、93%及84%.     

N-acetyl-beta-hexosaminidase: role in the degradation of glycosaminoglycans

Extracts of cultured normal human skin fibroblasts released radioactivity from a (14)C-labeled heptasaccharide prepared by addition of [(14)C]N-acetylgalactosamine to the nonreducing terminus of a hexasaccharide derived from chondroitin 4-sulfate whereas fibroblast extracts from patients with Tay-Sachs and Sandhoff-Jatzkewitz diseases did not. The results suggest that N-acetyl-beta-hexosaminidase A is responsible for degradation of the oligosaccharide substrate.     

甘肃省土壤曲霉属(Aspergillus Mich.ex Link:Fr.)的种

对140份来自甘肃各地的土样进行曲霉属（Aspergillus Mich．ex lank：Fr．）菌的分离，结合菌落形态及显微镜下孢子的形态将各菌鉴定到种。结果表明：甘肃省土壤中分布有7个种和3个变种。分别是烟曲霉原变种（Aspergillus fumigatus var．fumigatus）、烟曲霉椭孢变种（Aspergillus fumigatusvar．ellipticus）、烟束曲霉（Aspergillus fumisynnematus）、黄曲霉原变种（Aspergillus flavus var．flavus）、寄生曲霉（Aspergillus parasiticus）、刺孢裸胞壳（Emericella echinulata）、构巢裸胞壳（Emericella nidulans var．nidulans）、褶皱裸胞壳（Emericella rugulosa）、四脊裸胞壳（Emericella quadrilineata）及皱折裸胞壳（Emericella corrugata）。     

烟曲霉WY-1植酸酶基因的克隆及其在烟草中的表达

以自行筛选的烟曲霉WY-1为出发菌株,通过PCR方法克隆其植酸酶基因,并构建了含有植物信号肽序列的植酸酶基因植物表达载体,利用农杆菌介导的叶盘法对烟草叶片进行了遗传转化.结果表明,PCR鉴定和Southern杂交分析说明植酸酶基因已整合到烟草的基因组中;RT-PCR检测结果证实了植酸酶基因已得到转录表达;酶活性分析表明功能性的植酸酶已成功表达在烟草中,这是烟曲霉植酸酶基因在烟草中的首次表达.     

冷藏条件下鲢鱼肌肉蛋白的变化

利用聚丙烯酰胺凝胶电泳(SDS-PAGE)和免疫印迹法分析比较了鲢鱼在0和4℃下冷藏14 d过程中肌肉蛋白的变化情况.结果表明:在2种温度下冷藏,肌浆蛋白降解均不显著,其变化趋势基本一致;肌球蛋白重链在0℃下冷藏14 d,4℃下冷藏11 d后发生明显降解;α-辅肌动蛋白和肌动蛋白在2种温度下冷藏均呈逐渐降解的趋势,且在4℃下冷藏降解更为显著;原肌球蛋白在0和4℃下冷藏2 d后均开始降解,此后于0℃冷藏蛋白无明显变化,但于4℃冷藏11 d后降解速度加快.     

烟曲霉脱乙酰几丁质酶cDNA的克隆及其在大肠杆菌中表达的研究

将烟曲霉的一种胞外脱乙酰几丁质酶（AF CSN）纯化,并测定该酶N-端氨基酸的序列。用此序列推测的寡核苷酸引物扩增得到脱乙酰几丁质酶（csn）的cDNA,其全长为804bp,编码一种251个氨基酸的单肽,对csn的序列比较分析表明,它与茄病镰刀菌在两个区域具有同源性,这两个区域分别有重复天冬氨酸及苏氨酸残基,这说明它与细菌具有相同的演化起源。cns与已知的细菌脱乙酰几丁质酶没有同源性,Southern杂交分析显示,cns在烟曲霉基因组中的单拷贝的。用质粒栽体pET28a(t),csn cDNA被导入E.coli中得到csn的融合蛋白,在IPTG诱导下,E.coli细胞中可获得大量的约28kDa的成熟蛋白。     

ATP regulates the phosphorylation and degradation of myofibrillar proteins in ground ovine muscle

Phosphorylation post-translational modification plays an important role in postmortem muscle quality traits. Adenosine triphosphate (ATP) is an energy source and a key substrate of phosphorylation which provides the phosphatase groups to proteins in the presence of protein kinases. However, in postmortem muscle, the effects of ATP content on phosphorylation are poorly studied. The study investigated the effect of ATP on protein phosphorylation and degradation in postmortem ovine muscle. The ground muscle with/without additional ATP were treated/control groups and stored at 25 and 4°C, respectively. The ATP content led to different changes of pH value between the ATP-treated and control groups. The phosphorylation level of myofibrillar proteins was higher (P<0.05) in ATP-treated group compared to the control group at both temperatures, which suggested that ATP played a vital role in postmortem protein phosphorylation. A slower degradation rate of µ-calpain, desmin and troponin T was observed in the ATP-treated group which showed that there was a negative relationship between ATP level and the degradation of proteins. These observations clearly highlighted the role of ATP on the development of meat quality by regulating the phosphorylation and degradation of myofibrillar proteins in postmortem ovine muscle.     

基于林分结构和竹笋产量的有机材料覆盖雷竹林退化程度评价

为建立有机材料覆盖雷竹Phyllostachys praecox林退化程度评价体系，在浙江省临安市雷竹栽培区设置15个样点，在林分结构和竹笋产量等14项因子调查的基础上，进行主成分分析。研究表明，立竹年龄结构、立竹胸径和竹笋产量可作为雷竹林退化程度评价的主要指标；试验区有机材料覆盖雷竹林退化程度可分为4类6级：重度退化（Ⅰ级）、中度退化（Ⅱ，Ⅲ级）、轻度退化（Ⅳ，Ⅴ级）和正常（Ⅵ级）。重度、中度、轻度退化雷竹林所占比例分别为13.34%，26.66%，46.67%，未退化雷竹林仅占13.33%。有机材料覆盖易造成雷竹林立竹年龄结构不合理，立竹胸径减小，立竹整齐度、分布均匀度降低，竹林出现退化，竹笋产量显著下降。表5参20     

氰氟草酯(XDE-537)在土壤中的降解

在杭州市富阳郊区水稻田，研究了除草剂千金（有效成分为氰氮草酯，代号XDE-537）在土壤中的降解动态，测定了土壤样品中的XDE-537及其降解产物。结果表明，氰氟草酯在土壤中迅速降解至检测限以下，分解首先生成氰氟草酯的丙酸同系物（ACID），进一步形成的降解产物为无除草活性的二酸同系物（DIACID）。ACID的降解较缓慢，DIACID的形成与ACID的降解成负相关。由于氰氟草酯、ACID和DIACID在土壤环境中均分解较快，可以认为千金在环境中属非滞留性除草剂。     

Changes in atmospheric carbon-14 attributed to a variable sun

The (14)C production rate in the upper atmosphere changes with time because the galactic cosmic-ray flux responsible for (14)C production is modulated by the changes in solar wind magnetic properties. The resulting changes in the atmospheric (14)C level are recorded in tree rings and are used to calculate past (14)C production rates from a carbon reservoir model that describes terrestrial carbon exchange between the atmosphere, ocean, and biosphere. These past (14)C production rate changes are compared with (14)C production rates determined from 20th-century neutron flux measurements, and a theory relating (14)C production and solar variability, as given by geomagnetic Aa indices and sunspot numbers, is developed. This theory takes into account long-term solar changes that were previously neglected. The 860-year (14)C record indicates three episodes when sunspots apparently were absent: A.D. 1654 to 1714 (Maunder minimum), 1416 to 1534 (Sp?rer minimum), and 1282 to 1342 (Wolf minimum). A less precisely defined minimum occurred near A.D. 1040. The part of this record after A.D. 1645 correlates well with the basic features of the historical record of sunspot numbers. The magnitude of the calculated (14)C production rates points to a further increase in cosmic-ray flux when sunspots are absent. This flux was greatest during the Sp?rer minimum. A record of approximate sunspot numbers and Aa indices for the current millennium is also presented.     

烟草青枯病拮抗真菌烟曲霉发酵条件的优化

烟曲霉(Aspergillus fumigatus)对烟草青枯病菌(Ralstonia solanacearum)有稳定的拮抗作用,在验证其发酵液对烟苗生长无害的前提下,利用四因素(发酵温度、发酵时间、接种量、装液量)三水平三重复正交试验,测定该真菌的最佳发酵条件.结果表明,烟曲霉的最佳发酵条件为:发酵温度28℃、发醇...     

Extremely large variations of atmospheric 14C concentration during the last glacial period

A long record of atmospheric 14C concentration, from 45 to 11 thousand years ago (ka), was obtained from a stalagmite with thermal-ionization mass-spectrometric 230Th and accelerator mass-spectrometric 14C measurements. This record reveals highly elevated Delta14C between 45 and 33 ka, portions of which may correlate with peaks in cosmogenic 36Cl and 10Be isotopes observed in polar ice cores. Superimposed on this broad peak of Delta14C are several rapid excursions, the largest of which occurs between 44.3 and 43.3 ka. Between 26 and 11 ka, atmospheric Delta14C decreased from approximately 700 to approximately 100 per mil, modulated by numerous minor excursions. Carbon cycle models suggest that the major features of this record cannot be produced with solar or terrestrial magnetic field modulation alone but also require substantial fluctuations in the carbon cycle.     

CuO/MWCNTs复合材料降解双酚A的光催化性能

为改善氧化铜（CuO）的光催化性能,将CuO和多壁碳纳米管（MWCNTs）结合制备了CuO/MWCNTs复合材料。利用扫描电镜（SEM）、傅里叶红外光谱（FTIR）、X射线衍射（XRD）和紫外-可见漫反射（UV-Vis DRS）分析对Nano-CuO和CuO/MWCNTs进行形貌、成分、物相结构以及光学性质等一系列的表征与性能分析,结果表明CuO/MWCNTs同时具备CuO和碳纳米管的典型结构,且光吸收性能优于Nano-CuO。在紫外光下进行的两种光催化剂对双酚A（BPA）的光催化降解试验结果显示：两种催化剂作用下BPA光降解平衡的时间一致,均为24 h,但CuO/MWCNTs作为光催化剂时的BPA降解率和反应速率明显高于Nano-CuO,其中降解率高出幅度可达14%~35%;供试范围内,两种材料对BPA的光催化降解率均随催化剂投加量的增加而升高,随pH和离子强度的增加而减小,随BPA浓度的增加呈先增加后减小的趋势,且在相同条件下CuO/MWCNTs受到的影响更大,但其光催化降解率仍远高于Nano-CuO的光催化降解率。研究表明,CuO/MWCNTs复合材料可以显著提高光催化效率及对紫外光的利用率,有效推进了CuO的光催化应用与发展。     

多菌灵在地黄及土壤中的残留动态研究

采用固相萃取法净化、高效液相色谱法(HPLC)测定,建立了地黄及土壤中多菌灵残留的检测方法,并研究了多菌灵在地黄块根、叶片及土壤中的消解动态和最终残留情况。结果表明:多菌灵在0.017 5～5.18μg/mL范围内峰面积与质量浓度间有良好的线性关系,检出限为0.046ng,定量限为0.092 mg/kg,其在地黄块根、叶片以及土壤中的添加回收率分别介于86.42%～95.07%、84.73%～89.95%和90.54%～95.61%,相对标准偏差为1.38%～3.68%、2.71%～7.72%和3.63%～7.76%。多菌灵在地黄块根中的消解方程为C=0.052 0e-0.100 8t,半衰期6.88d;在叶片中的消解方程为C=3.584 3e-0.259 2t,半衰期2.67d;在土壤中的消解方程为C=0.051 6e-0.074 0t,半衰期9.36d。施药14d后,多菌灵在地黄块根、叶片及土壤中的残留均降至0.1mg/kg以下,未超出我国规定的多菌灵在果蔬上的最大允许残留量(0.5mg/kg)。     

Effects of inhibitors on the protease profiles and degradation of activated Cry toxins in larval midgut juices of Cnaphalocrocis medinalis(Lepidoptera: Pyralidae)

Midgut juice plays an important role in food digestion and detoxification in insects. In order to understand the potential of midgut juice of Cnaphalocrocis medinalis(Guenée) to degrade Bt proteins, the enzymatic activity of midgut juice and its degradation of Bt proteins(Cry2 A, Cry1 C, Cry1 Aa, and Cry1 Ac) were evaluated in this study through protease inhibitor treatments. The activities of total protease in midgut juices were significantly inhibited by phenylmethylsulfonyl fluoride(PMSF), tosyl-L-lysine chloromethyl ketone(TLCK), pepstatin A and leupeptin. The enzymatic activity of chymotrypsin was significantly inhibited by PMSF, and enzymatic activity of trypsin was significantly inhibited by ethylenediaminetetraacetic acid(EDTA), PMSF, tosyl phenylalanine chloromethyl ketone(TPCK), TLCK and trans-epoxysuccinyl-L-leucylamido-(4-guanidino) butane(E-64). EDTA could significantly inhibit the degradation of Cry2 A by C. medinalis. EDTA, PMSF, TPCK, and TLCK could inhibit the degradation of Cry1 C and Cry1 Aa. EDTA, PMSF, TPCK, TLCK, and E-64 could inhibit the degradation of Cry1 Ac. Our results indicated that some protease inhibitors hindered various enzymatic activities in the larval midgut of C. medinalis, which may reduce the insect's ability to degrade Bt toxins. These findings may aid the application of protease inhibitors in the management of this insect pest in the future.     

基于木质素单体含量的园林生物质降解菌评价

基于降解剩余物中木质素单体含量变化,对园林生物质降解菌的酶解效果进行评价。以羧甲基纤维素钠为唯一碳源,对天然林下腐植质层降解菌进行功能筛选和分子鉴定;通过正交实验优化酶活力、降解试验分析降解失重率,经气相色谱-质谱联用技术测定降解剩余物中木质素单体含量,并综合评价降解效率。结果表明:酶活力较高的株菌QL-1、QL-4分别为曼氏假单胞菌(Pseudomonas mandelii)和烟曲霉(Aspergillus fumigatus),其纤维素酶活力分别为14.10 U·mL~(-1)和8.15 U·mL~(-1);培养10 d时两株菌的降解失重率达到最高,分别为9.48%和13.91%,是未添加降解菌株即空白对照组的2.49倍和3.66倍;愈创木基和紫丁香基木质素单体含量均有显著减少,10 d时QL-4试验组的净降解率为15.57%,是QL-1的3.15倍。研究表明,筛选所得烟曲霉具更强降解活力,其降解剩余物中木质素单体含量均有不同程度下降。