马铃薯细菌多样性解析及促生高产 IAA菌株的筛选

采用 3种不同的培养基从马铃薯根际土壤和叶片中共分离出 78株细菌,优势菌属是 Pantoea,占菌株总数的 55.13%。马铃薯根际土采用 R2A培养基(27株优势菌,13个菌属)分离的细菌多样性相对较好,阿须贝培养基(31株优势菌,9个菌属)次之,土壤浸提液培养基(1株优势菌,1个菌属)最少;马铃薯叶片内生菌用阿须贝培养基(19株优势菌,3个菌属)分离的细菌多样性较差。采用 Salkowski比色液显色法定量测定菌株产 IAA能力,结果表明有 58株细菌具有分泌 IAA的能力,占测定菌株总数的 74.36%,从马铃薯根际土(42株优势菌,13个菌属)筛选的产 IAA菌数量及细菌多样性均高于马铃薯叶片内生菌(16株优势菌,2个菌属)。根据菌株产IAA能力强弱和分离部位及分离培养基的差异,选择 7株产 IAA菌进行促生特性和马铃薯盆栽幼苗促生能力等研究,结果显示:有 6株产 IAA菌具有 ACC脱氨酶能力,1株产 IAA菌具有溶解无机磷能力,2株产 IAA菌具有溶解有机磷能力;两轮温室促生实验结果显示,菌株 Pantoeasp.MLS-34-25对马铃薯幼苗具有明显的促生作用,是生产微生物肥料的潜在菌种。     

鸡传染性支气管炎病毒肾致病株的分离和鉴定

从广西13个鸡场,有呼吸道症状及尿石症的病鸡中分离出 C、G、Z、Q4株病毒。病毒经电镜观察,其大小在94～108nm 之间,囊膜外有特征性疏松排列的刺突。敏感鸡接种16～36小时后出现呼吸道症状,剖检病鸡时大多数鸡肾肿大并有尿酸盐沉积。各毒株接种鸡胚都能产生体儒胚;被56℃1小时灭活;在鸡胚中均能干扰鸡新城疫病毒 LaSota 株的生长。C_(19)株可被鸡传染性支气管炎病毒标准阳性血清所中和。G_3不被 IUDR 所抑制,属 RNA 病毒;对乙醚敏感,证明属有囊膜病毒。从以上各项鉴定指标证明,所分离的4株病毒是引起鸡尿石症的传染性支气管炎病毒。据作者的经验,提出分离鸡传染性支气管炎病毒较为合理的模式。     

酸马奶酒中微生物的分离鉴定及抗菌特性的研究

从内蒙古锡盟不同地区采集15份酸马奶酒样品,经分离纯化、归属种鉴定,并单菌发酵液经调pH值、蒸发酒精、浓缩后,对李斯特杆菌、金黄色葡萄球菌、大肠杆菌进行抑菌研究。结果表明,酸马奶酒是由多种乳酸菌和酵母菌共同发酵的乳饮料。其中乳酸菌中有球菌5个属,杆菌6个属,酵母菌6个属。乳酸菌中有9株乳球菌和12株乳杆菌对李斯特杆菌有抑制作用,对大肠杆菌和金黄色葡萄球菌无抑制作用。酵母菌中有4株对大肠杆菌有抑菌作用,其中有2株同时对金黄色葡萄球菌有抑制作用,对李斯特杆菌无抑制作用     

西北部分矿区豆科植物根瘤菌重金属抗性及16S rDNA RFLP分析

从生长在西北部分矿区的豆科植物根瘤中分离筛选到对重金属有抗性的38株根瘤菌,采用PCR-RFLP分子技术进行16S rDNA指纹图谱分析,选取每种类型的代表菌株进行16S rDNA全序列测定,建立系统发育树状图,并对38株菌进行Zn、Hg、Cu、Cd和Pb5种重金属的抗性研究。结果表明,供试菌株分别归属于中华根瘤菌属（Sinorhizobium）、根瘤菌属（Rhizobium）和土壤杆菌属（Agrobacterium）。代表菌株CCNWSX1277和CCNWSX1294可耐受2.0mmol·L-1的Zn2＋,CCNWSX1277可耐受0.25mmol·L-1的Hg2＋,多数代表菌株可耐受1.6mmol·L-1的Cu2＋,仅3株代表菌株可以耐受Cd2＋,其中CCNWSX1277能耐受1.4mmol·L-1的Cd2＋,所有代表菌株能耐受2.5mmol·L-1的Pb2＋。Agrobacterium属的2株代表菌株对5种重金属均有较强的耐受性;而Rhizobium属的4株菌和Sinorhizobium属的3株菌对5种重金属的耐受性不同,表现出较大的差异。总体来看,供试菌株对重金属的耐受性顺序为Agrobacterium〉Rhizobium〉Sinorhizobium。     

广西沿海地区红树林根系土壤中放线菌的分离与鉴定

本研究通过分离纯培养,从广西北海及防城港红树林根系土壤中分离出放线菌并提取其总DNA,用放线菌通用引物对获得菌株的16SrDNA进行PCR扩增,对获得的扩增产物进行DNA序列测定及菌株鉴定。研究结果表明,从红树林根系土壤样品中分离出15株典型放线菌菌株。16SrDNA测序比对鉴定结果显示,15株典型放线菌菌株中有12株属于链霉菌属（Streptomyces）,是常见菌属;3株属于拟诺卡氏菌属（Nocardiopsis）,为稀有放线菌。本研究分离纯化获得15株典型放线菌,初步揭示了广西沿海地区红树林土壤中放线菌的多样性。     

烟草根表可培养细菌群落组成及典型菌群的促生特性研究

植物微生物组是维护植物生长发育、提升抗逆防病的重要调控因素。为发挥植物微生物促进烟草生长、改善烟草根区微生态功能作用,本研究从烟草根表分离筛选可培养细菌组,并对不同菌株的促生能力进行测定。结果表明：(1)从烟草根表分离并鉴定出可培养菌株310株,隶属于31个属,其中主要为芽孢杆菌属(Bacillus)、假单胞菌属(Pseudomonas);(2)对比分析发现假单胞菌属、芽孢杆菌属、寡养单胞菌属(Stenotrophomonas)和成对杆菌属(Dyadobacter)为4种供试土壤烟草根表共有的细菌类群;(3)对进一步筛选得到的16株菌株进行促生能力的测定,发现6株菌具有固氮能力,5株菌产铁载体,4株菌可溶解无机磷,4株菌产IAA;(4)盆栽试验验证16株菌株的促生效果,其中37.5%的菌株对烟草生长具有显著促进作用,烟草株高、总鲜物质量和地下部干物质量分别比对照提高35.1%、27.9%和30.7%。总之,从烟草根表分离获得多种具有促生能力的菌株,为未来构建促进烟草健康生长的复合菌剂提供了理论基础。     

呼伦贝尔草甸草原优势种群根际微生物多样性研究

采用分离培养和生理生化试验等方法,对呼伦贝尔草甸草原优势种群羊草和贝加尔针茅根际土壤微生物多样性及优势菌株进行了研究。结果表明,3类土壤样本微生物总数由高到低依次为:羊草>贝加尔针茅>对照组,但差异不显著(p>0.05);样地中呈现:细菌总数>放线菌总数>真菌总数,细菌与放线菌和真菌均呈显著差异(p<0.01)。在羊草根际土壤中分离到的优势菌株为细菌7个属36株,放线菌4个属21株,真菌3个属17株。     

猪生殖和呼吸综合征病毒中国分离株B13株ORF5基因在杆状病毒系统中的表达

本研究将PRRSV B13株ORF5基因克隆到杆状病毒转移载体质粒pVL1393中,构建了重组转移载体质粒pVL1393-ORF5.用该重组转移载体质粒与线性化苜蓿丫纹夜蛾核型多角体病毒(AcMNPV-SVI-G)基因组DNA(BaculoGold Linearized Baculovirus DNA)共转染草地夜蛾(Spodoptera frugiperda,sf9)细胞,得到重组病毒AcMNPV-OCC-- ORF5 .在感染了重组病毒的sf9细胞中成功地检测到分子量为25kD的ORF5基因表达产物,其能被猪抗PRRSV B13株多克隆血清特异识别.表明sf9细胞表达了所期望的产物,进而也说明基因片段的正确性.猪抗PRRSV VR-2332株多克隆血清对ORF5基因的表达产物无反应,而猪抗LV株多克隆血清则能特异识别,说明PRRSV中国分离株B13株在抗原性上更接近欧洲亚群分离株LV株的抗原性,进一步证实了PRRSV中国分离株B13株属于欧洲亚群.ORF5基因表达产物与天然蛋白分子量十分接近,说明杆状病毒表达系统能较适当的进行合成蛋白的加工和修饰.本研究的结果为PRRS基因工程疫苗的研究奠定了基础.     

天水市麦积区古树资源分布调查

为摸清天水市麦积区古树资源分布状况,2020 — 2021年采用“古树名木信息管理系统”和古树名木App管理软件对天水市麦积区区内现存古树资源(古树及古树群)进行调查。结果表明,分布于麦积区的古树有333株,隶属23科28属34种(含种下等级),其中一级古树110株,二级古树61株,三级古树162株。现存古树群7个。古树区域分布以甘泉镇最多,有74株;马跑泉镇和麦积镇较多,分别有66、52株。约70%的古树生长势处于濒危衰弱状态。古树科层面的分布区类型有5种,分布区变型有1种;古树属层面的分布区类型有7种,分布区变型有3种。古树区系主要特征为北温带区系成分占优势,表现植物区系由亚热带向温带过渡的特点。     

茄子黄萎病发病程度与根际土壤线虫种群数量的关系研究

研究结果表明茄子根围和根内线虫种群数量与茄子黄萎病发病程度有密切关系,重病株根围线虫密度明显高于轻病株和无病株;重病株根内线虫密度也明显高于轻病株和无病株;发病地块茄子根际与非根际线虫密度无明显差异;线虫与黄萎病菌混合接种茄子,黄萎病发病率显著高于仅接黄萎菌,且接线虫数越多其发病程度越重;混合接种较仅接线虫茄子根内线虫密度明显升高。经鉴定寄生茄子根的线虫主要为垫刃线虫属(Tylenchus)、短体线虫属(Prathylenchus)、矮化线虫属(Tylenchornychus)和滑刃线虫属(Aphelenchoidae)。     

鸡传染性支气管炎病毒肾致病株的致弱及免疫研究

用已鉴定的广西鸡传染性支气管炎病毒(IBV)分离株G,C,Z和Q分别通过鸡胚传代进行致弱,在一定代次时分别接种敏感鸡作毒力测定试验.然后用已致弱的毒株在实验室进行攻击保护试验,最后取已致弱而且抗原性良好的毒株在广西各地鸡场进行田间应用试验。结果表明,C株在传至40代时,G,Z和Q株分别传至20代时对鸡的毒性均已大大降低;免疫鸡用标准强毒株(M_(41))攻击,然后用病毒回收的技术来衡量其免疫力,结果各株经免疫两次后均有很好的保护率(60％～100％),均显著优于对照组(P<0.01);致弱株分别在南宁、柳州、容县、岑溪和博自5县市的11个鸡场进行田间试验,试验的鸡有30群共103761羽,试验时分别对疫苗免疫对鸡生产性能的影响、安全性和育成率进行观察和测算,结果表明,作者培育的IBV弱毒苗对鸡是安全的,使用C_(60)或C_(80)和G_(20)株先后两次免疫鸡,对IB有较好预防效果,这些弱毒株有希望成为供生产使用的疫苗。     

The flavonol quercetin-3-glucoside inhibits cyanidin-3-glucoside absorption in vitro

At present, little is known about the mechanisms responsible for intestinal absorption of anthocyanins (ACNs). For example, it has not yet been established if ACNs are absorbed through an active transport mechanism, such as the sodium-dependent glucose transporter (SGLT1), or by passive diffusion. Previously, we found that the absorption of ACNs differs between regions of the digestive tract and is maximal in the jejunum, suggesting that an active transport mechanism is involved. In the present study, we examined the effect of d-glucose (main substrate of SGLT1), phloridzin (inhibitor of SGLT1), and quercetin-3-glucose (Q3G, a flavonol) on the absorption of cyanidin-3-glucoside (C3G; approximately 5 micromol/L) by mouse jejunum mounted in Ussing chambers. We found that the presence of either D-glucose (10, 20, and 40 mmol/L) or phloridzin (50, 100, and 200 micromol/L) resulted in a small but insignificant inhibition of C3G disappearance from the mucosal solution (decrease of disappearance with glucose, 33%; with phloridzin, 18%; NS). However, when the flavonol Q3G (50 micromol/L) was added to the mucosal solution together with the C3G, the disappearance of C3G was significantly decreased (74%; p < 0.001), and Q3G disappeared instead. In addition, we found phloretin and quercetin, the aglycones of phloridzin and Q3G, respectively, present in the mucosal solution and tissue extracts, indicating hydrolysis of these compounds by the enterocytes of the jejunum. In contrast, the aglycone cyanidin was not detected at all. Our results show that in the mouse small intestine, ACN absorption is not solely dependent on the activity of the SGLT1 transporter, as d-glucose and phloridzin had only a slight effect on uptake. Q3G, however, clearly inhibited C3G disappearance. These results suggest that there might be a competitive inhibition between C3G and Q3G absorption. It is possible that an absorption mechanism other than the SGLT1 is involved, which has a structural preference toward flavonols.     

Radiolysis of quercetin in methanol solution: observation of depside formation

Radiolysis of the flavonol quercetin, a natural antioxidant, was performed in methanol. The degradation process was followed by HPLC analyses. The major product was identified as a depside (Q1) by NMR and LC-MS. The G(Q1) radiolytic factor was plotted versus the initial concentration of quercetin. This radiolytic process was attributed to the CH3O* radicals presented in the irradiated medium. The proposed mechanism invoked a stereospecific oxidation of the 3-hydroxyl group of quercetin which led to C-ring opening and to the formation of the depside Q1. In presence of water, Q1 was transformed into another depside, Q2, by an inverse esterification reaction. A chemical equilibrium was observed between Q1 and Q2. The comprehension of the radiolytic process of quercetin in methanol solution is of importance. Indeed, the same type of oxidative reactions could occur on flavonoids during preservation of food by ionizing radiation.     

Quercetin-4'-glucoside is more potent than quercetin-3-glucoside in protection of rat intestinal mucosa homogenates against iron ion-induced lipid peroxidation

Quercetin is a typical antioxidative flavonoid found in vegetables, which is more commonly present as its glucosides, quercetin-3-glucoside (Q3G) and quercetin-4'-glucoside (Q4'G). The main aim of this study was to estimate the antioxidant activity of Q3G and Q4'G on iron ion-driven lipid peroxidation of the gastrointestinal mucosa. Q4'G markedly suppressed the lipid peroxidation when rat gastrointestinal mucosa homogenates were incubated with Fe(NO3)3 and ascorbic acid. Its effectiveness was greater as compared to that of Q3G and comparable to that of quercetin aglycone. Furthermore, Q4'G yielded higher amounts of quercetin aglycone than Q3G on incubation with the homogenates. However, Q4'G showed a lower chelating activity in comparison to Q3G. These results indicate that Q4'G, even though it has a low chelating activity, because of its efficient conversion to antioxidative aglycone on exposure to the mucosa, can act as a powerful antioxidant on iron ion driven lipid peroxidation in the intestinal mucosa. Thus, vegetables rich in Q4'G, such as onion, are likely to serve as favorable antioxidant sources for suppressing iron-induced oxidative stress in the intestinal tract.     

污水灌溉对苜蓿生长下土壤部分理化性质的影响

通过盆栽试验研究了污水、再生水等不同灌溉水质对苜蓿三次刈割后土壤部分理化性质的影响。结果表明:相对于清水灌溉,污水及再生水处理能显著降低土壤pH值,增加EC值。第二次刈割时污水、再生水处理与清水相比土壤无机氮含量分别增加了63.59%和35.02%,第三次刈割时分别增加了82.18%和30.72%。与清水灌溉相比,污灌处理土壤Cd含量在三次刈割中分别增加了33%,117.65%和138.89%,再生水灌溉处理在三次刈割中分别增加了13.33%,64.71%和61.11%。根据《土壤环境质量标准》进行土壤重金属污染评价表明,在本试验期间各灌溉水质处理未引起土壤Pb污染,但未经处理的污灌处理造成了Cd污染。本研究初步说明污水采用混灌与轮灌方式可适当减缓其不利效应;再生水可作为苜蓿的灌溉用水,但其长期效应仍需进一步深入研究。     

Determination of the relative contribution of quercetin and its glucosides to the antioxidant capacity of onion by cyclic voltammetry and spectrophotometric methods

This paper describes the use of cyclic voltammetry (CV), spectrophotometric methods [Trolox equivalent antioxidant capacity (TEAC), peroxyl radical trapping capacity (PRTC), DPPH radical scavenging activity (RSA), and Folin-Ciocalteu reagent (FCR) reducing capacity], and photochemiluminescence (PCL) for the measurement of the antioxidant capacity of onion var. Sochaczewska and var. Szalotka. The antioxidant and reducing activity of the dominant onion flavonoids quercetin (Q), quercetin-3- O-beta-glucoside (Q3G), quercetin-4'- O-beta-glucoside (Q4'G), and quercetin-3,4'-di- O-beta-glucoside (Q3,4'G) were determined by spectrophotometric (TEAC and PRTC) and CV methods, respectively. The contribution of quercetin and its glucosides to the antioxidant capacity of onion was calculated in consequence of the qualitative and quantitative analysis of onion flavonoids by high-performance liquid chromatography-ultraviolet-mass spectrometry. The dominant forms of quercetin in the onion var. Sochaczewska and Szalotka included Q4'G (61 and 54%), Q3,4'G (37 and 44%), Q3G (1.4 and 1.1%), and free quercetin (1.1 and 0.7%), respectively. The CV experiment showed the highest reducing activity of Q while Q3G, Q4'G, and Q3,4'G exhibited about 68, 51, and 30% of the reducing power noted for Q. The order of the reducing activity of onion flavonoids was confirmed by their free radical scavenging activity and evaluated by TEAC and PRTC assays as follows: Q > Q3G > Q4'G > Q3,4'G. The Q4'G and Q3,4'G showed poor antioxidant activity under both applied spectrophotometric assays but still exhibited reducing activity based on CV experiments. The reducing capacity of onions determined by CV method was twice higher than the antioxidant capacity formed by water-soluble compounds (ACW) evaluated by PCL, and it was about 50% higher than PRTC and DPPH RSA results and the converted FCR reducing capacity. In contrast, the reducing capacity of onions determined by the CV method was 3-fold and about four times lower when compared to the antioxidant capacity evaluated by the TEAC method and that formed by lipid-soluble compounds (ACL) provided by PCL, respectively. The highest antioxidant capacity of onion was found under cumulative consideration of PCL (ACW + ACL) and TEAC assays. The relative contribution of Q and its glucosides to the antioxidant capacity of onions showed a low contribution of Q, Q3G, and Q3,4'G derived from CV, TEAC, and PRTC assays while the highest contribution to the antioxidant capacity of onions was provided by Q4'G.     

适应玉米的溶磷细菌筛选及其对玉米生长的影响

从石灰性土壤中分离获得4株高效溶磷细菌X5、X6、Z4和Z8,研究其生物学特征,探索其单独及复合的溶磷促生潜能。研究发现菌株X5、X6、Z4和Z8均可以利用玉米根系分泌物作碳源生长。菌株X6和Z4均能产生吲哚乙酸(IAA)和铁载体,菌株Z8可产生IAA不产生铁载体,菌株X5可产生铁载体不产生IAA。盆栽试验结果表明,接种单一溶磷菌及4株菌复合处理均可促进玉米生长,但复合菌群的溶磷促生效果显著高于单一菌株。通过16S r RNA基因序列分析研究菌株的分类地位,初步鉴定X5、X6、Z4、Z8分别为荧光假单孢菌(Pseudomonas fluorescens)、草假单胞菌(Pseudomonas poae)、巨大芽孢杆菌(Bacillus megaterium)和枯草芽孢杆菌(Bacillus subtilis)。     

前伸式双叶片污水泵内部流场PIV试验

以一台比转速为70的前伸式扭曲双叶片污水泵为研究对象,采用PIV(particle image velocimetry)技术对双叶片污水泵进行内部流场测量,分析了该泵在不同流量工况下(Q/Qdes=0.4、0.6、0.8、1、1.2、1.4)叶轮内部流场的相对速度分布,研究了轴向旋涡和低速区随流量变化的形态特性,发现在流道中部靠近叶片工作面上存在低速区及与叶轮旋转方向相反的轴向旋涡,且随着流量的增大,低速区与轴向旋涡逐渐减小;引入少叶片数离心泵内部流动理论,揭示了低速区和轴向旋涡存在和发展的内在机理。分析了在流量Q/Qdes=0.6时叶轮和蜗壳不同相对位置的相对速度场分布,研究了叶轮和蜗壳之间动静干涉作用对轴向旋涡的影响,发现当轴向旋涡经过蜗壳隔舌时,其与叶轮之间的干涉作用使得轴向旋涡向下游偏移。研究结果对前伸式扭曲双叶片污水泵的内部流动规律研究具有重要参考价值。     

种子蛋白质电泳在陆地型长绒棉种质鉴定中的应用

采用垂直平板聚丙烯酰胺凝胶法 ,进行单粒种子醇溶蛋白质电泳分析 ,参试材料有陆地型长绒新种质 9830 1系、4个海岛棉品种和 8个陆地棉品种。 9830 1和中棉所 1 2号、石远 32 1在试验中 ,同一品种 (系 )内的不同种子之间的蛋白谱带基本一致。对分别取样于山东省 7个不同地区试验点的 9830 1种子谱带进行比较 ,没有发现差异。胶板上陆地棉品种均具有 3条与海岛棉相区分的带 ,同样各海岛棉品种也共同具有 3条特征带。 9830 1显出 3条陆地棉特有带 ,证明其谱带主要倾向于陆地棉 ;同时也稳定地出现 1条海岛棉的特有带 ,表现出其属于海陆杂交种的遗传特性。 9830 1分离出一条独有带 (“1”带 ) ,凭借此带和另一条带 (“1 0”带 )可较容易地和其它陆地棉品种相区分     

Lipoxygenase inhibitory activity of anacardic acids

6[8'(Z)-pentadecenyl]salicylic acid, otherwise known as anacardic acid (C15:1), inhibited the linoleic acid peroxidation catalyzed by soybean lipoxygenase-1 (EC 1.13.11.12, type 1) with an IC50 of 6.8 microM. The inhibition of the enzyme by anacardic acid (C15:1) is a slow and reversible reaction without residual activity. The inhibition kinetics analyzed by Dixon plots indicates that anacardic acid (C15:1) is a competitive inhibitor and the inhibition constant, KI, was obtained as 2.8 microM. Although anacardic acid (C15:1) inhibited the linoleic acid peroxidation without being oxidized, 6[8'(Z),11'(Z)-pentadecadienyl]salicylic acid, otherwise known as anacardic acid (C15:2), was dioxygenated at low concentrations as a substrate. In addition, anacardic acid (C15:2) was also found to exhibit time-dependent inhibition of lipoxygenase-1. The alk(en)yl side chain of anacardic acids is essential to elicit the inhibitory activity. However, the hydrophobic interaction alone is not enough because cardanol (C15:1), which possesses the same side chain as anacardic acid (C15:1), acted neither as a substrate nor as an inhibitor.