生物炭与脲酶抑制剂及保水剂配施对贵州辣椒的影响

为探究生物炭与不同土壤添加剂配施在贵州黄壤辣椒上的施用效果,采用大田试验,选用酒糟生物炭、脲酶抑制剂和保水剂作为供试材料,研究增施生物炭(FB)、生物炭与脲酶抑制剂(FBU)或保水剂(FBW)两两配施、生物炭与脲酶抑制剂和保水剂(FBUW)三者同时施用对辣椒产量、品质、养分吸收累积、肥料利用率和经济效益的影响。结果表明,与常规施肥(F)相比,增施土壤添加剂可显著增加辣椒鲜产,增加幅度17.91%~28.74%,产值增加20 351~29 700元·hm^-2,增幅为167.14%~243.93%,其中以三者同时施用(FBUW)效果最佳,达到20 938 kg·hm^-2;生物炭与脲酶抑制剂或(和)保水剂配施可降低辣椒果实中硝酸盐含量6.32%~34.00%,以FBUW降幅最大,且三者同时施用还可显著提高果实中的游离氨基酸含量;与F相比,增施土壤添加剂使氮、磷、钾肥的表观利用率分别提高了4.13~10.80个百分点、-0.98~8.72个百分点和6.36~27.56个百分点,而氮、磷、钾肥的农学效率则分别提高了8.09~12.98、16.18~25.97和8.99~14.42 kg·kg^-1,均以FBUW最佳;与F相比,增施土壤添加剂后的辣椒纯收入提高了0.83%~23.21%,以FBUW效果最佳。综上,在常规施肥基础上,生物炭、脲酶抑制剂和保水剂三者同时配施产生的协同效应优于单独施用或两两配施。本研究结果为土壤添加剂在贵州黄壤辣椒高产栽培技术中的应用提供了理论依据。     

珠穆朗玛峰北坡土壤脲酶和中性磷酸酶活性初步研究

研究了珠穆朗玛峰北坡地区沿绒布河谷海拔4400～5550m的夏季土壤中水解酶类脲酶、中性磷酸酶活性,并探讨了这两种土壤酶与土壤有机质和海拔高度的相互关系。结果表明:(1)随着海拔升高,土壤脲酶、中性磷酸酶活性呈高低波动变化,在研究区域出现多个峰值,总的趋势是上升的,其最大值分别出现在海拔5500m和5450m处。(2)偏相关分析表明,土壤脲酶活性与有机质含量呈正相关,土壤中性磷酸酶活性与有机质含量呈显著正相关;土壤脲酶活性与海拔的相关性不具显著性意义,中性磷酸酶活性与海拔呈极显著正相关。     

寄生原虫嘌呤磷酸核糖转移酶研究进展

寄生原虫是一类单细胞寄生性原虫,包括利什曼原虫（Leishmania spp.）、锥虫（Trypanosoma spp.）、疟原虫（Plasmodium spp.）、刚地弓形虫（Toxoplasma gondii）、隐孢子虫（Cryptosporidium spp.）和艾美耳球虫（Eimeria spp.）等,可引起严重危害人类与动物健康以及对养殖业造成巨大经济损失的原虫病。寄生虫入侵宿主后的发育和繁殖需要大量的嘌呤核苷酸,相应的嘌呤碱基在嘌呤磷酸核糖转移酶的催化下生成对 应的嘌呤核苷酸。嘌呤磷酸核糖转移酶是一类参与嘌呤核苷酸补救合成的重要代谢酶,广泛存在于寄生原虫中。寄生原虫的嘌呤磷酸核糖转移酶主要包括腺嘌呤磷酸核糖转移酶和次黄嘌呤 - 鸟嘌呤 - 黄嘌呤磷酸核糖转移酶,两者在寄生原虫中分别催化腺嘌呤核苷酸、次黄嘌呤核苷酸、鸟嘌呤核苷酸和黄嘌呤核苷酸合成,从而参与寄生原虫的多个生化代谢过程,不仅为寄生原虫核酸生物合成等提供前体物质,还为虫体提供通用能量载体。由于寄生原虫的嘌呤补救途径明显区别于宿主的从头合成途径,且嘌呤磷酸核糖转移酶是寄生原虫嘌呤补救途径的关键酶,因而近年来寄生原虫嘌呤磷酸核糖转移酶成为抗原虫药物候选靶标的研究热点,以寄生原虫嘌呤磷酸核糖转移酶为潜在靶标,特异性筛选、设计抑制剂,并开发抗寄生原虫药物取得重要进展。以利什曼原虫、锥虫、疟原虫和弓形虫的嘌呤磷酸核糖转移酶为重点,综述寄生原虫嘌呤磷酸核糖转移酶的基本特征、生物学功能、抑制剂筛选与应用的研究进展,以期为抗寄生原虫药物靶标研究与新型抑制剂筛选提供参考。     

The serine protease inhibitors and SERPINE1/2 disrupt prostaglandin E2 production and hyaluronic acid retention in FSH‐stimulated pig cumulus–oocyte complexes

The serine proteases, tissue‐ and urokinase‐type plasminogen activators (PLAT and PLAU) and their inhibitors SERPINE1/2 are regulators of plasminogen to plasmin conversion. They are widely expressed in ovarian tissues, including granulosa and cumulus cells, and their expression is regulated by gonadotropins. The aim of this work was to assess the effect of serine protease inhibitors (aprotinin and AEBSF) and SERPINE1/2 on FSH‐induced cumulus cell expansion, the production of prostaglandin E2 (PGE2) and retention of hyaluronic acid (HA) in expanding cumulus. The serine protease activity proved to be essential for the production of PGE2 and also for the retention of HA; the inhibition of plasminogen activators by SERPINE1/2 had the same effect. Collectively, these data indicate that plasmin is required for proper function of expanding cumulus cells in vitro and presumably also in vivo in the pre‐ovulatory follicles.     

土壤脲酶活性两种测定方法的比较

利用比色法和扩散法对金强河地区和甘肃农业大学校园内的土壤脲酶活性进行了分析。结果表明：比色法和扩散法测定的土壤脲酶活性平均值分别为（0．531±0．207）mg／g和（0．446±0．204）mg／g,两种测定方法的结果和变异系数差异均不显著（P〉0．05）。但从试验操作方面考虑,扩散法操作比较简单、所用药品种类少、时间短,是一种比较可行的土壤脲酶活性测定方法。     

Nitrate leaching loss following application of organic manures to sandy soils in arable cropping.

Abstract. Experiments were set up at two sites to measure nitrogen (N) leaching loss from applications of separated pig/cattle slurry and cattle farmyard manure(FYM), during winters 1990/91–1993/94 (site A) and from broiler litter and FYM, during winters 1990/91–1992/93 (site B). The manures were applied at a target rate of 200 kg ha^-1 total N during the autumn and winter to overwinter fallow or top dressed onto winter rye. The total N in leachate was calculated from leachate N concentrations, in samples collected using ceramic cups buried at 90 cm, and an estimate of drainage volume. Nitrogen losses were greatest following manure applications in September, October and November but losses following applications in December or January were not significantly elevated above those from untreated controls. Losses were consistently lower from FYM than from broiler litter or separated slurry. The presence of a cover crop (winter rye) significantly reduced overall N leaching compared with the fallow, but only reduced the manure N leaching losses at one site during one winter when a high proportion of drainage occurred late. The incorporation of a nitrification inhibitor (DCD) with manures applied in October did not significantly reduce the manure N leaching.     

温度和底物对陕西土壤脲酶活性的影响

在不同温度和底物浓度条件下,对陕西７种土壤１９个土样脲酶的活性进行了测定。结果显示,在一定温度和底物浓度范围内,随温度和底物浓度增加,脲酶活性升高,在不同温度和浓度区段,影响幅度有明显差异,除水稻土外,其余高肥力土样脲酶活性受其影响较大;在同一生态区中,脲酶活性与理化性质呈极显著正相关,土壤脲酶活性可作为土壤肥力水平高低的重要指标之一;土壤脲酶作用的最适温度为６０℃．     

土壤粘粒吸附脲酶量的影响因子研究

研究了８种土壤粘粒对脲酶的吸附量,以及不同ｐＨ,温度和Ｚｎ（Ⅱ）、Ａｓ（Ⅴ）、Ｈｇ（Ⅱ）质量浓度对脲酶吸附量的影响。结果表明,８种土壤粘粒对脲酶均有吸附,但吸附数量不尽相同。非最适ｐＨ时,脲酶吸附量在弱碱性介质中的下降率大于弱酸性介质;温度升高,脲酶吸附量下降,且去有机质土壤粘粒的下降率大于原样土壤粘粒;Ｚｎ（Ⅱ）、Ａｓ（Ⅴ）、Ｈｇ（Ⅱ）抑制相同比率的脲酶吸附量时,所需３种离子的质量浓度为Ａｓ（Ⅴ）＞Ｚｎ（Ⅱ）＞Ｈｇ（Ⅱ）,表现为Ｈｇ（Ⅱ）的抑制作用最强。     

大麦根中多胺含量和转化与耐盐性的关系

用0、50、100、200和300mmol·L-1NaCl对2个耐盐性不同的大麦品种鉴4(J4,耐盐性较强)和科品7号(KP7,耐盐性较弱)幼苗处理8d后,其干重均随着NaCl浓度增加而显著下降,叶片MDA含量和相对电导率相应增加。与对照相比,J4干重的降低要小于KP7,MDA含量和相对电导率也比KP7低。在盐胁迫下,大麦幼苗根系的多胺含量和种类也有显著的变化,随NaCl浓度的增加,腐胺(Put)含量先下降后上升,而亚精胺(Spd)含量的变化则相反,这种多胺含量变化的盐浓度阈值J4大于KP7。多胺合成抑制剂D-Arg、二氟甲基鸟氨酸(DFMO)和甲基乙二醛双(鸟嘌呤腙)(MGBG)可以显著降低盐胁迫下多胺含量,不同程度上加重了盐胁迫的伤害,表明植物体内多胺在盐胁迫适应中具有重要的作用。