白洋淀水位变化及其对东亚飞蝗大发生的影响

根据近50年白洋淀最高水位、入淀水量、出淀水量和降水量等资料，分析了白洋淀水位变化呈现的特点及原因；并结合东亚飞蝗的生长发育特点，探讨了水位的年际、年内变化对东亚飞蝗大发生的影响。结果表明，近50年白洋淀最高水位呈波动中降低趋势，白洋淀逐月水位年内差异逐渐变小。原因主要为上游来水大量减少所致。白洋淀水位年际变化中，峰值回落阶段和波谷地段对应的年份易于东亚飞蝗大发生。5～10月白洋淀逐月水位偏低有利于东亚飞蝗大发生。这些结论为白洋淀水量调控和预防东亚飞蝗大发生提供依据。     

结核分枝杆菌CFP10-ESAT6融合蛋白的真核表达及其牛结核病诊断价值评价

本研究旨在利用毕赤酵母(Pichia pastoris)系统融合表达结核分枝杆菌(Mycobacterium tuberculosis,MTB)的培养滤液蛋白10(culture filter protein 10,CFP10)和早期分泌抗原靶6蛋白(earlier secreted antigen target 6,ESAT6),并评价其作为牛结核病外周血γ-干扰素(interferon gamma,IFN-γ)体外释放实验特异性刺激剂来诊断牛结核病的应用潜能.通过PCR扩增cfp1 0-esat6融合基因,构建pPICZα A-(cfp10-esat6)重组质粒,电转化毕赤酵母GSll5,添加甲醇至终浓度1.0％,诱导3d,取培养上清进行SDS-PAGE分析,镍离子金属螯合亲和层析柱纯化目的蛋白,Western blot分析重组蛋白的免疫反应性;取纯化的融合蛋白CFP10-ESAT6作为刺激剂用于牛结核病外周血IFN-γ体外释放实验,评价其牛结核病诊断价值.结果表明,目的蛋白(33kD)被成功分泌表达,该融合蛋白与抗CFP10、ESAT6、组氨酸标签和c-Myc4种单抗均发生特异性反应,具有较好的免疫反应性.165份奶牛外周血样品的IFN-γ检测结果表明,CFP 10-ESAT6融合蛋白与结核菌素纯蛋白衍生物(purified protein derivative,PPD)作为刺激剂,二者阳性符合率为82.3％,阴性符合率为78.8％.本研究利用酵母表达系统成功表达CFP10-ESAT6融合蛋白,并表现出更高的生物学活性,在牛结核病外周血IFN-γ体外释放实验中可作为候选刺激剂,并能克服混合感染导致的PPD漏检问题,从而进一步提高检测的敏感性和特异性.     

Antioxidant properties of water extracts from Cassia tora L. in relation to the degree of roasting

The antioxidant properties of water extracts from Cassia tora L. (WECT) prepared under different degrees of roasting were investigated. The water extracts of unroasted C. tora L. (WEUCT) showed 94% inhibition of peroxidation of linoleic acid at a dose of 0.2 mg/mL, which was higher than that of alpha-tocopherol (82%). Water extracts prepared from C. tora L. roasted at 175 degrees C for 5 min and at 200 degrees C for 5 min exhibited 83% and 82%, respectively, inhibition of linoleic acid peroxidation. This result indicated that the antioxidant activities of WECT decreased with longer roasting time or higher roasting temperature. The IC(50) of WEUCT in liposome oxidation induced by the Fenton reaction was 0.41 mg/mL, which was higher than that of alpha-tocopherol (IC(50) = 0.55 mg/mL). WEUCT also exhibited good antioxidant activity in enzymatic and nonenzymatic microsome oxidative systems. The water extracts of roasted C. tora L. increased in the degree of browning and produced chemiluminescence when compared with the unroasted sample. However, the total polyphenolic compounds of WECT decreased after the roasting process finished. In conclusion, the decrease in the antioxidant activity of water extracts from roasted C. tora L. might have been due to the degradation of Maillard reaction products and the decrease of polyphenolic compounds.     

Propagule size: Its relation to population density of microorganisms in soil

Analysis of published data on occurrence of bacteria and fungi in soil revealed an inverse linear relationship between the logarithm of propagule size and the logarithm of population density among these microorganisms. The regression equation Y= 8.841? 0.540.X (in which Y is log numbers of propagules kg^?1 of soil and X is log volumes per 100 propagules), describing the relationship between propagule size and maximum population density of microorganisms in soil, afforded the predicted values of the population density very close to the reported values. The regression equation may also be used for predicting the possible propagule type of a microorganism in soil, if its population density is known.     

地膜覆盖结合秸秆深埋条件下盐渍土壤呼吸及其影响因素

【目的】研究土壤呼吸排放特征及其影响因素是评价土壤碳平衡的基础。本课题组前期研究发现在地表下35 40 cm处埋设作物秸秆隔层结合地表地膜覆盖,具有明显的耕层控抑盐效果。但由于秸秆隔层结合地膜覆盖调控土壤微环境,可能影响土壤CO2的排放。然而,相关研究特别是基于野外试验的研究还比较缺乏,不利于正确评价该技术措施的综合效应。为此本研究拟通过相关试验揭示不同耕作方式对河套灌区盐渍化土壤呼吸的影响。【方法】本文以位于河套灌区实施秸秆深埋三年后的典型盐碱地农田为研究对象,观测研究地膜覆盖结合秸秆深埋条件下盐渍化土壤呼吸及温度、水分、盐分、有机质等影响因素的动态变化。该研究主要分析翻耕(CK)、翻耕结合地膜覆盖(PM)、上盖地膜下埋秸秆(PM+SL)和秸秆深埋(SL)4种耕作措施下盐渍化土壤呼吸速率的动态变化及其与影响因素的关系。【结果】1)4种耕作方式的土壤呼吸速率在食葵全生育期内均呈降低趋势,PM+SL处理在整个生育期内土壤呼吸速率最高,PM次之,SL处理呼吸速率仅在蕾期较CK略高,其余时期与CK基本持平,在盛花期、成熟期10:00和15:00两个关键时间点各处理间土壤呼吸值同样表现为:PM+SLPMSLCK;各耕作方式0—40 cm土壤温度变化趋势保持一致,仅在收获期出现差异;PM+SL处理0—40 cm土壤含水量在所有处理中均为最低值,但其在控盐和增加有机质上明显优于其它处理;2)土壤呼吸速率与0—40 cm土壤温度呈极显著的正相关关系(P0.01),与0—40 cm土壤水分、盐分、有机质含量无相关性。拟合方程显示盐渍化土壤呼吸受土壤温度、水分、盐分的综合效应影响。【结论】干旱区域盐渍化土壤的呼吸速率受土壤温度、水分、盐分等因素的综合影响,在该区域通过上盖地膜下埋秸秆等相应措施起到保温抑盐效果的同时,可增强食葵根系生长以及微生物的代谢活动。     

Correlation of phenolic metabolism with histological changes in Phaseolus vulgaris inoculated with fungi

Acetone powders were prepared at intervals after inoculation ofPhaseolus vulgaris, variety Topcrop, with fungi inciting hypersensitive (Helminthosporium carbonum), resistant (Colletotrichum lindemuthianum, gamma race), and susceptible (C. lindemuthianum, beta race) host responses. Phenylalanine ammonia-lyase activity was determined in extracts of the acetone powders, and quantitative and qualitative measurements were made of phenolic compounds in the acetone filtrates obtained during powder preparation. The developmental morphology of the fungi on host tissue was observed histologically. The data obtained indicate that host-fungus physiology is accompanied by readily detectable and specific alterations of phenolic metabolism during various stages of infection and host response. Phaseollin production in hypocotyls inoculated withC. lindemuthianum accompanied the appearance of symptoms in resistant and susceptible reactions; it was produced earlier and in greater amount in resistant reactions.Samenvatting Acetonpoeders werden bereid op verschillende tijdstippen na inoculatie vanPhaseolus vulgaris, cv. Topcrop, met schimmels, die een overgevoelige, resistente of vatbare reactie in de gastheer induceren. De activiteit van fenylalanine-ammonia-lyase werd bepaald in extracten van de acetonpoeders, en de fenolen werden kwantitatief en kwalitatief bepaald in de acetonfiltraten, die verkregen werden gedurende de bereiding van het poeder. De morfologische ontwikkeling van de schimmels op het weefsel van de waardplant werd histologisch bestudeerd. De verkregen gegevens wijzen erop dat de fysiologische processen, die in de combinatie van waardplant en schimmel optreden, gedurende verschillende stadia van infectie en reactie van de waardplant, gepaard gaan met duidelijk aantoonbare en specifieke veranderingen in de fenol stofwisseling. Zowel bij resistente als vatbare reacties ging het verschijnen der symptomen gepaard met de vorming van phaseolline in hypocotylen geïnoculeerd metColletotrichum lindemuthianum; bij de resistente reacties werd het eerder en in grotere hoeveelheden gevormd.Journal Paper No. 3470 of the Purdue University Agricultural Experiment Station.     

猪痘病毒江西株(SWPV-JX01株)的分离鉴定

本试验利用PK15细胞从江西省某猪场疑似猪痘的保育猪皮肤痘痂中分离到1株病毒,该分离毒株在PK15单层细胞上能连续盲传培养,不产生明显的细胞病变,通过PCR扩增猪痘病毒P35基因,扩增序列与猪痘病毒参考株(AF410153.1)P35基因的核苷酸同源性为97.9%,表明该分离病毒为猪痘病毒,并命名为SWPV-JX01。将SWPV-JX01株F5代细胞培养液经肌肉和皮下注射感染兔和小鼠,人工感染80 h后,通过PCR检测不同组织的猪痘病毒P35基因,从兔的肾脏、脾脏、皮肤、心肌、淋巴结均能扩增到P35基因,且扩增序列与SWPV-JX01株同源性为100%。试验结果表明,SWPV-JX01株能在兔体内增殖,但不能在昆明鼠体内增殖。     

Mass spectral analysis of urine proteomic profiles of dairy cows suffering from clinical ketosis

Background: Ketosis is an important metabolic disorder in dairy cows during the transition period. The urine proteomics of ketosis has not been investigated using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS).

Objective: The aim is to determine differences between urine proteomic profiles of healthy cows and those with clinical ketosis, and facilitate studies of the underlying physiological and biochemical mechanisms that lead to liver pathology in ketosis.

Animals and methods: We analyzed the urine samples of 20 cows with clinical ketosis (group 1) and 20 control cows (group 2) using SELDI-TOF-MS.

Results: Thirty-nine peptide peaks differed between both groups. Polypeptides corresponding to 26 of these differential peptide peaks were identified using the SWISS-PROT protein database. We found that the peaks of 11 distinct polypeptides from the urine samples of the ketosis group were significantly reduced, compared with those of the control group as based on the Wilcoxon rank sum test. Among these were VGF (non-acronymic) protein, amyloid precursor protein, serum amyloid A (SAA), fibrinogen, C1INH, apolipoprotein C-III, cystatin C, transthyretin, hepcidin, human neutrophil peptides, and osteopontin.

Conclusion: These proteins may represent novel biomarkers of the metabolic changes that occur in dairy cows with ketosis. Our results will help to better understand the physiological changes and pathogenesis observed in cows with ketosis.

Clinical importance: The SELDI-TOF-MS can be used to understand the physiological and biochemical mechanisms of ketosis and identify biomarkers of the disease.     

氮肥施加条件下增温对硝化菌活性和丰度的影响

温度在多种生物地球化学过程中起到关键的调节作用,是影响土壤硝化作用和微生物分布的重要因素之一。硝化过程的第1个步骤由氨氧化细菌(AOB)和氨氧化古菌(AOA)催化,然而,不同施氮量下,增温对硝化菌活性和丰度的影响尚不清楚。本研究基于2008年10月起设立于太行山山前平原的长期增温试验平台(高于地表2m的红外加热器使土壤温度升高1.5℃),于2018年5月对不施氮(N0)和施氮[N1,240kg(N)·hm-2·a-1]下增温分别对0～10 cm和10～20 cm土壤硝化潜势(PNR)、AOA和AOB丰度的影响进行了研究。硝态氮(NO3--N和铵态氮(NH4+-N)含量用分光光度法测量,应用缓冲液培养法测定土壤PNR,提取土壤DNA后用实时荧光定量PCR技术测定功能基因AOA和AOB的丰度。结果表明:温度升高显著增加N1条件下PNR和NO3--N含量(P0.05),降低了N0条件下PNR和NO3--N含量,但差异不显著。N1条件下,增温土壤AOB丰度显著提高(P0.05); N0条件下,增温土壤AOA丰度显著降低(P0.05)。与N0相比, N1条件下的AOA/AOB比值明显降低,表明增温加氮肥处理对AOB的生长刺激更强烈。在增温加施氮条件下,细菌(AOB)表现显著的正反应,在增温不施氮条件下,古菌(AOA)和AOB表现显著的负反应。本研究结果可为全球增温背景下进一步了解硝化活性和氨氧化微生物对增温和氮有效性的响应提供科学依据。