蛇足石杉内生真菌产黄青霉菌MT-40中xanthocillin类似物生物合成基因簇的挖掘及鉴定

Xanthocillin具有显著的抗菌活性,结构中含有独特的异腈基。本文通过对蛇足石杉(Huperzia serrata)内生真菌产黄青霉菌(Penicillium chrysogenum)MT-40基因组的测序分析,利用本地BLAST等生物信息学分析工具挖掘具有合成xanthocillin类似物潜力的基因簇,结合米曲霉(Aspergillus oryzae)NSAR1异源表达技术实现基因簇中关键基因的功能鉴定。结果成功从内生真菌P.chrysogenum MT-40中发现一个合成xanthocillin类似物的生物合成基因簇(命名为for),for基因簇中的关键生物合成基因forB编码的异腈基合成酶可以催化合成2-formamido-3-(4-hydroxyphenyl)acrylic acid,基因forG编码的P450酶可以催化2-formamido-3-(4-hydroxyphenyl)acrylic acid的二聚化生成xanthocillin类似物N,N′-(1,4-bis(4-hydroxyphenyl)buta-1,3-diene-2,3-diyl)diformamide。本文研究结果为进一步从真菌中发现xanthocillin类似物提供参考。     

棉田生态系统能流特征分析

为丰富生态系统的能流功能理论,开展以此为基础的生态调控,本文采用田间调查与室内测定相结合的方法,系统地测定了棉田初级生产者（棉株）、次级生产者（害虫、天敌）和土壤分解者的能流参数值,分析和比较了以棉株－害虫－天敌相互作用为中心,受人为干扰作用较大的棉田生态系统能流特征。     

Preparation and structural characterization of large heparin-derived oligosaccharides

Porcine mucosal heparin was partially depolymerized with heparinlyase I and then fractionated into low-molecularweight (<5000)and high-molecular-weight (>5000) oligosaccharides by pressurefiltration. The high-molecular-weight oligosaccharide mixture({small tilde}50 wt% of the starting heparin) also containedintact heparin. This intact polymer complicates oligosacsharidepurification. Thus, the low-molecular-weight fraction was usedto prepare homogeneous oligosaccharides for structural characterization.The low-molecular-weight oligosaccharide mixture was first fractionatedby low pressure gel permeation chromatography into size-uniformmixtures of disaccharides, tetrasaccharides, hexasaccharides,octasaccharides, decasaccharides, dodecasaccharides, tetradecasaccharidesand higher oligosaccharides. Each size-fractionated mixturewas then purified on the basis of charge by repetitive semi-preparativestrong-anion-exchange high-performance liquid chromatography.This approach has led to the isolation of 14 homogeneous oligosaccharidesfrom disaccharide to tetradecasaccharide. The purity of theseheparin-derived oligosaccharides was determined by gradientpolyacrylamide gel electrophoresis, analytical strong-anion-exchangehigh-performance liquid chromatography, capillary electrophoresisand one-dimensional nuclear resonance spectroscopy. The structureof these oligosaccharides was established using 600 MHz two-dimensionalnuclear resonance spectroscopy . The spectral methods used includedhomonuclear correlation spectroscopy, nuclear Overhauser effectspectroscopy and heteronuclear multiple quantum coherence spech-clscopy.The ¹H/¹H connectivities of the protons of each sugar residuein an oligosaccharide were established by two-dimensional homonuclearcorrelation spectroscopy, while ¹H/¹³C assignments were madeusing ¹H inverse detection. One- and two-dimensional nuclearresonance spectroscopic analysis of these heparin oligosaccharidesshowed two closely related groups of heparin-oligosaccharidesare afforded by enzymatic depolymerization of heparin. One groupis fully sulphated, having the structures     

红铃虫性诱剂开口纤维剂型及其在棉田中的竞争引诱作用

Hummel等1973年鉴定了红铃虫的性外激素是顺,顺-和顺,反-7,11-十六碳二烯-1-醇醋酸酯的复合物,并命名为“红铃虫性诱剂”(简称“Gossyplure”)。Biel等1974年用触角电图和大田诱捕试验,证明当两种异构体的配比为1∶1时效果最好。为延长性诱剂在大田中的有效期,研究工作者曾设计了多种释放器和可控缓释剂型。Shorey等1976年用铝圆筒包上尼龙纱作为释放器,红铃虫性诱剂的释放量为每晚5毫克/公顷,全年用量为9克/公顷。Gaston等1977年用内径0.22毫米、外径0.45毫米、长104毫米,一端开口一端封闭的塑料空心纤维,绕成直径22毫米的环作释放器,每次用量6.6克/公顷,全年用33克/公顷。Boncss等1977和1978年用聚乙烯盖作释放器,每次用量5克/公顷,胶囊剂     

Presence of nadph-cytochrome P-450 reductase in rat liver golgi membranes: Evidence obtained by immunoadsorption method

Light Golgi fractions (GF(1+2)) prepared from rat liver homogenates by a modification of the Ehrenreich et al. procedure (J. Cell Biol. 59:45) had significant NADPH-cytochrome P(450) reductase (NADPH-cyt c reductase) activity if assayed immediately after their isolation. An antibody raised in rabbits against purified microsomal and Golgi fractions. To find out whether this activity is located in bona fide Golgi elements or in contaminating microsomal vesicles, we used the following 3-step immunoadsorption procedure: (a) antirabbit IgG (raised in goats) was conjugated to small (2-5 μm) polycrylamide (PA) beads; (b) rabbit anti NADPH-cyt c reductase was immunoadsorbed to the antibody-coated beads; and (c) GF(1+2) was reacted with the beads carrying the two successive layers of antibodies. The beads were then recovered by centrifugation, and were washed, fixed, embedded in agarose, and processed for transmission electromicroscopy. Antireductase- coated beads absorbed 60 percent of the NADPH-cyt c reductase (and comparable fractions of NADH-cyt c reductase and glucose-6-phosphatase) but only 20 percent of the galactosyltransferase activity of the input GF(1+2). Differential vesicle counts showed that approximately 72 percent of the immunoadsorbed vesicles were morphologically recognizable Golgi elements (vesicles with very low density lipoprotein [VLDL] clusters or Golgi cisternae); vesicles with single VLDL and smooth surfaced microsome-like vesicles were too few (approximately 25 percent) to account for the activity. It is concluded that NADPH-cytochrome P(450) reductase is a Golgi membrane enzyme of probably uneven distribution among the elements of the Golgi complex.     

温度对干旱、盐胁迫下两种黄芪属种子萌发和幼苗生长的影响

为探讨温度对干旱、盐胁迫下黄芪属种子萌发和幼苗生长特性的影响,以黄芪属蒙古黄芪和扁茎黄芪2种种子为研究对象,纯净水处理为对照组,NaCl、PEG处理为实验组,设置4个渗透势水平(0、-0.1、-0.3、-0.5 MPa),置于5种不同的温度(10、15、20、25、30 ℃)下,每日观察并记录两种种子萌发和幼苗生长情况。结果表明：旱盐胁迫下蒙古黄芪和扁茎黄芪种子萌发最适宜的温度分别为25和20 ℃左右;蒙古黄芪耐高温不耐低温,而扁茎黄芪恰恰相反;但25和20 ℃均适宜两种幼苗生长,包括胚根、胚轴和子叶的生长。蒙古黄芪各处理组(除未发芽的种子)的平均发芽时间都比扁茎黄芪长;NaCl胁迫程度的增加使得两种种子的最终发芽率降低,但蒙古黄芪的耐盐性高于扁茎黄芪;随着PEG胁迫程度的增加,二者的发芽均受到抑制,甚至会出现完全不萌发,但扁茎黄芪的耐旱性高于蒙古黄芪;在相同的渗透势时,尤其是-0.5 MPa,PEG比NaCl对两种种子的影响大;交互胁迫作用下,随着渗透势的增加两种幼苗的鲜重、干重以及胚根、胚轴、子叶的长和宽变化较大;利用Design Expert软件预测发现：温度25 ℃、NaCl渗透势为-0.1 MPa,温度24 ℃、PEG渗透势为-0.04 MPa的处理是蒙古黄芪种子萌发和幼苗生长达到最优化的组合;而扁茎黄芪最优化的组合则为23 ℃下NaCl渗透势为-0.07 MPa的处理,20 ℃下PEG渗透势为-0.13 MPa的处理。     

单孔、两孔及三孔胸腔镜下早期非小细胞肺癌根治术的效果比较研究

目的:通过比较不同胸腔镜手术方式治疗早期非小细胞肺癌根治术术后的相关临床指标,为临床手术方式提供经验。方法:收集我院2017年1月～2019年12月收治的行肺癌根治术的早期非小细胞肺癌病例共100例,分别采用单孔胸腔镜(40例),两孔胸腔镜(32例)及三孔胸腔镜(28例)手术方式,比较三组手术术中及术后的相关指标。结果:单孔胸腔镜组术中出血量、术后引流量明显少于两孔胸腔镜组和三孔胸腔镜组(P0.05),而两孔胸腔镜组明显少于三孔胸腔镜组(P0.05);单孔胸腔镜组术后胸管留置时间和术后住院时间均短于两孔胸腔镜组和三孔胸腔镜组(P0.05),而两孔胸腔镜组明显短于三孔胸腔镜组(P0.05)。三组组内疼痛评分术后24h低于术后12h,术后48h低于术后24h,差异均有统计学意义(P0.05)。三组组间不同时间点疼痛评分比较发现,单孔胸腔镜组疼痛评分低于两孔胸腔镜组和三孔胸腔镜组(P0.05),而两孔胸腔镜组低于三孔胸腔镜组(P0.05)。三组清扫淋巴结数目、淋巴结站数和术后并发症发生率差异均无统计学意义(P0.05)。结论:单孔胸腔镜早期非小细胞肺癌根治术与两孔、三孔胸腔镜手术相比优势明显,且不会显著增加术后并发症,可作为临床首选。     

钨酸钠对苹果幼苗15N吸收利用、13C积累及果实品质的影响

分别以1年生苹果砧木M9T337幼苗和5年生烟富3/SH6/平邑甜茶为试材,开展盆栽和田间试验,并结合¹⁵N、¹³C同位素示踪技术,研究不同浓度(0、0.5、1、1.5 mmol·L^-1,分别用CK、T₁、T₂和T₃表示)硝酸还原酶(NR)抑制剂钨酸钠对苹果幼苗¹⁵N吸收利用、¹³C积累和成熟期果实品质的影响。结果表明: 盆栽试验中,喷施0.5~1.0 mmol·L^-1钨酸钠可显著抑制幼苗地上部生长,但对根系生长影响不显著;当钨酸钠浓度达到1.5 mmol·L^-1时可显著抑制根系生长。同一时期各处理叶片NR活性与钨酸钠浓度呈负相关,均表现为CK>T₁>T₂>T₃。随处理时间的延长,叶片硝态氮含量总体表现为先升高后降低的趋势,同一时期各处理硝态氮含量与钨酸钠浓度呈正相关,均表现为T₃>T₂>T₁>CK。喷施钨酸钠可不同程度地降低幼苗各器官¹⁵N吸收量和¹⁵N利用率,且钨酸钠浓度越高,抑制幼苗氮素吸收和利用的效果越显著。随钨酸钠浓度的提高,地上部¹³C积累量呈先升高后降低的趋势,在T₂处理时达到最高;幼苗整株¹³C积累量呈相似的规律。田间试验结果表明,喷施钨酸钠可降低成熟期叶片和果实的氮含量,果皮花青苷含量、果实可溶性固形物、可溶性糖含量和糖酸比均不同程度提高,其中T₂处理的效果最好。综上,T₂处理(1.0 mmol·L^-1钨酸钠)可有效抑制幼苗地上部生长,降低¹⁵N吸收利用,提高¹³C积累,有利于果实品质的提高。     

不同水肥一体化方式对苹果氮素吸收利用特性及产量和品质的影响

以‘嘎啦/八棱海棠’为试材,借助¹⁵N同位素示踪技术,研究了撒施(T₁)、滴灌施氮(T₂)和渗灌施氮(T₃)对嘎啦苹果氮素吸收利用、分配特性和产量品质的影响,以期进一步完善苹果园水肥一体化技术,挖掘提高氮素利用率的途径。结果表明: T₃处理苹果叶片的叶面积、叶绿素和氮含量显著高于T₁和T₂处理。各时期土壤矿化氮(N_min)含量在20~40 cm土层表现为T₃＞T₂＞T₁处理,在0~20 cm土层表现为T₂＞T₃＞T₁处理。同一器官的Ndff值(树体各器官从肥料中吸收到的¹⁵N占该器官全氮量的比例)在各时期均以T₃处理最高,T₂其次,T₁处理最低。果实成熟期的树体¹⁵N利用率表现为T₃＞T₂＞T₁处理,其中T₃处理的树体¹⁵N利用率为24.2%,分别是T₂和T₁处理的1.19和1.65倍。果实成熟期T₁处理的¹⁵N分配率在营养器官最高,T₂处理在贮藏器官最高,T₃处理在生殖器官最高。各处理的单果重、产量、可溶性固形物、硬度、可溶性糖及糖酸比均以T₃处理最高,T₂其次,T₁处理最低。渗灌施氮处理显著促进了嘎啦苹果树体叶片生长和氮素利用,并提高了果实产量和品质。     

微藻源生物刺激剂的制备及在设施农业中的应用

化肥和农药的过量使用导致的农业面源污染已经成为我国环境污染的重要组成部分,对农业绿色高效安全生产及设施农业带来了巨大挑战。寻找新型的传统化肥替代品、提高化肥使用效率及保护生态环境是亟待解决的重大问题。生物刺激剂是具有调控植物生长作用的成分和(或)微生物的统称,用于农业生产,可改善土壤理化性质与群落微生物,能促进作物的代谢与生长,增强对营养物质的吸收和利用,提升作物抗逆能力及提高作物产量与产品品质。微藻体内具有结构新颖、功能独特的天然活性物质,是制备新型生物刺激剂的理想来源。微藻用于环境治理的同时,可获得足量的微藻生物质来制备生物刺激剂,从而达到治理环境、降低成本及提质增效的目的。就微藻源生物刺激剂的定义及功能、微藻全细胞和天然活性物质生物刺激剂的制备、应用效果及对植物和土壤的作用原理进行综述,以期为微藻源强效生物刺激剂的规模化制备及农业生产应用奠定理论基础和提供生产实践指导。