黄瓜细菌性白枯病CU-PV 07菌株鉴定及16S rDNA序列分析

由CU-PV 07菌株引起的黄瓜细菌性白枯病已成为黄瓜生产上的主要病害.弄清该致病菌株分类地位及基因序列,对做好病害诊断和防治有重要意义.通过症状观察与对致病菌的生理生化分析、16S rDNA序列分析,结果表明:该病害症状为叶片病斑圆形或近圆形,中间白色膜质,四周具晕圈,病部未见菌脓;CU-PV 07菌株菌体杆状,菌体大小为(1.1～5.2)μm×(O.7～2.1)μm;革兰氏染色反应阴性,鞭毛极生1-2根;分析生理生化指标和16S rDNA序列同源性可知.该病菌CU-PV 07菌株与Pseudomonasviridiflava一致,在构建的系统演化树上应为同一个族群.可见.黄瓜细菌性白枯病菌的病原为绿黄假单胞菌[Pseudomonas viridiflava(Burkholder 1930)Dowson 1939].     

Comparative Metabolomics Reveals Fungal Conversion of Co-Existing Bacterial Metabolites within a Synthetic Aspergillus-Streptomyces Community

In nature, secondary metabolites have been proven to be the essential communication media between co-occurring microorganisms and to influence their relationship with each other. In this study, we conducted a metabolomics survey of the secondary metabolites of an artificial co-culture related to a hydrothermal vent fungal–bacterial community comprising Aspergillus sclerotiorum and Streptomyces and their reciprocal relationship. The fungal strain was found to increase the secretion of notoamides and the compound cyclo(Pro-Trp) produced by the actinomycetes strain was discovered to be the responsible molecule. This led to the hypothesis that the fungi transformed cyclo(Pro-Trp) synthesized by the actinomycetes as the biosynthetic precursors of notoamides in the chemical communication. Further analysis showed Streptomyces sp. WU20 was efficient in transforming amino acids into cyclo(Pro-Trp) and adding tryptophan as well as proline into the chemical communication enhanced the induction of the notoamide accumulation. Thus, we propose that the microbial transformation during the synthetic metabolically-mediated chemical communication might be a promising means of speeding up the discovery of novel bioactive molecules. The objective of this research was to clarify the mechanism of microbial transformation for the chemical communication. Besides, this research also highlights the utility of mass spectrometry-based metabolomics as an effective tool in the direct biochemical analysis of community metabolites.     

乳酸菌胞外多糖提取条件的研究

影响乳酸菌胞外多糖提取效果的因素较多,采用Savage法去除蛋白,发酵上清液浓缩到原体积的1/3,加入3倍体积的无水乙醇进行醇沉,选择8000r/min作为醇沉溶液的离心速度,离心2次,透析12h以上,对保加利亚乳杆菌产胞外多糖进行提取,达到了较好的提取效果。     

Integrating marker assisted background analysis with foreground selection for identification of superior bacterial blight resistant recombinants in Basmati rice

Basmati rice is highly susceptible to bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae. Transfer of BB resistance genes from non‐Basmati sources to Basmati through cross‐hybridization requires strict monitoring for recovery of the desirable Basmati quality traits in the recombinants, which show complex inheritance pattern. We integrated background analysis using mapped microsatellite markers with foreground selection to identify superior lines that combine useful genes from a non‐Basmati BB resistance donor line IRBB55 with grain and cooking quality characteristics of the popular Basmati rice variety ‘Pusa Basmati 1’ (PB 1) employing backcross pedigree strategy. Foreground selection using linked markers ensured presence of two genes, xa13 and Xa21 for BB resistance from IRBB55, and the recurrent parent PB 1 allele for the waxy locus giving intermediate amylose content and maintainer allele at fertility restorer locus in the BC₁F₅ recombinants. Background analysis enabled selection of recombinants with recurrent parent genome to the extent of 86.3% along with the quality traits. The extent of introgression of non‐Basmati donor chromosome segments in the superior selections was estimated to be < 7.8 Mb and < 6.7 Mb in the xa13 and Xa21 linked genomic regions, respectively. Association mapping identified three quantitative trait loci, one each for 1000‐grain weight, fertile grains/panicle and cooked kernel length. The backcross‐pedigree breeding strategy facilitated recovery of additional desirable characteristics from the donor in some of the selections. The elite selection Pusa 1460‐01‐32‐6‐7‐67 with maximum genomic background and quality characteristics of the recurrent Basmati parent gave resistance reaction against BB, similar to that of the non‐Basmati resistant check variety and recorded an yield advantage of 11.9% over the best check in the multiplication agronomic trial in the Basmati growing region of India. This line, which has been released as a new variety in the name of ‘Improved Pusa Basmati 1’ for commercial cultivation in India, is an example of successful application of marker assisted selection to variety development.     

黄芩黄酮对小鼠生长性能和抗氧化能力及盲肠微生物的影响

选取3周龄昆明小鼠40只,随机分成4组,分别为对照组(CON)及黄芩黄酮低剂量组(HQHTL)、中剂量组(HQHTM)、高剂量组(HQHTH),对照组每天用0.9%氯化钠溶液灌胃,黄芩黄酮组每天分别用25、50、100 mg/kg的黄芩黄酮溶液灌胃,灌胃28 d后测定小鼠的生长性能、抗氧化能力和盲肠的微生物多样性及群落组成。结果表明：与CON相比,用黄芩黄酮灌胃显著(P<0.05)提高了小鼠的平均日增质量;小鼠的血清总超氧化物歧化酶活性显著(P<0.05)或极显著(P<0.01)升高,丙二醛水平显著(P<0.05)或极显著(P<0.01)降低;HQHTM和HQHTH小鼠的盲肠微生物Sobs和Bootstrap指数显著(P<0.05)下降,Chao和Ace指数极显著(P<0.01)下降;HQHTM和HQHTH小鼠的盲肠放线菌门(Actinobacteriota)相对丰度显著(P<0.05)上升,疣微菌门(Verrucomicrobiota)相对丰度极显著(P<0.01)上升,HQHTH小鼠的盲肠脱铁杆菌门(Deferribactero...     

Ensiling vine tea (Ampelopsisgrossedentata) residue with Lactobacillusplantaruminoculant as an animal unconventional fodder

The study aimed to evaluate the application of silage fermentation in storing vine tea residue.  Dynamic of fermentation-related product, chemical component and bacterial community of silage with or without Lactobacillus plantarum F1 inoculant were analyzed.  The results showed that F1 treatment had a significant (P<0.05) impact on the lactic acid and ammoniacal nitrogen concentrations and pH value.  Total phenols were well preserved in both treatments.  After 30 days of ensiling, L. plantarum occupied the majority of Lactobacillus genus (more than 95%) in all silage samples.  Spearman revealed a positive (P<0.01) correlation between lactic acid content and Lactobacillus.  Overall, ensiling vine tea residue with L. plantarum can effectively preserve the nutritional attributes and total phenols, which offers a new insight into utilizing vine tea residue.     

细菌纤维素对鸡肉品质及蛋白性质的影响

【目的】探究细菌纤维素(Bacterial cellulose,BC)对鸡肉品质及蛋白性质的影响。【方法】向鸡肉中分别添加质量分数为0.2%,0.6%和1.0%的BC,以100%肉(CM)、90%肉+10%水(CW)和添加质量分数2.0%微晶纤维素(Microcrystalline cellulose,MCC)的鸡肉为对照组,测定烘烤之后鸡肉饼的保水性、质构特性、颜色及微观结构,利用动态流变仪对生鸡肉的储能模量(G′)和损耗模量(G″)进行测定,采用差示扫描量热仪(DSC)和傅里叶中红外光谱(FTIR)测定BC对鸡肉蛋白变性温度和化学基团的影响。【结果】持水力结果表明,鸡肉饼的水分损失率随BC添加量的增加而降低,当BC添加量为1.0%时,水分损失率最小(12.82%),且显著小于CM(13.95%)和CW(15.48%)。激光共聚焦扫描显微镜结果显示,随BC添加量的增加,鸡肉中油滴尺寸逐渐减小且分布更加均匀。扫描电镜图片进一步证明,BC和蛋白质良好兼容,鸡肉饼的微观结构更加紧凑。常温下,添加BC的鸡肉,其G′和G″明显高于对照组,且与BC的添加量呈正相关。温度升高时,G′和G″随BC添加量的增加而降低。DSC和FTIR结果表明,BC对鸡肉蛋白的变性温度与化学基团无显著影响。【结论】BC具有良好的保水性,添加BC(0.2%～1.0%)可以不同程度降低鸡肉饼的水分损失;BC不影响鸡肉蛋白的变性与化学基团的变化,表明BC与蛋白质之间的作用力属于非共价相互作用。当BC添加量为0.6%时,其对鸡肉品质的改善效果最佳。     

冬季不同类型猪舍内颗粒物与微生物气溶胶浓度分布规律研究

本研究旨在探究冬季不同类型猪舍内颗粒物与微生物气溶胶的污染特征,为改善规模化猪舍内空气质量提供基础数据。采用TSI粉尘监测仪和ZYK-6型六级筛孔撞击式微生物采样器,对妊娠舍、分娩舍和保育舍三种类型猪舍内的不同粒径颗粒物(TSP、PM_(10)、PM_4、PM_(2.5)和PM_1)浓度以及微生物气溶胶进行监测和采样。监测和采样高度均设为距离地面0.8 m处,每日监测7次(3:00、7:00、9:00、11:00、15:00、17:00和22:00),连续监测3 d。结果显示:妊娠舍内TSP、PM_(10)、PM_4、PM_(2.5)和PM_1平均质量浓度分别为1.734、0.760、0.313、0.270 mg·m~(-3)和0.249 mg·m~(-3),细菌气溶胶浓度范围6800～25 600 cfu·m~(-3),真菌气溶胶浓度范围为170～870 cfu·m~(-3);分娩舍内TSP、PM_(10)、PM_4、PM_(2.5)和PM_1平均质量浓度分别为3.102、1.385、0.492、0.408 mg·m~(-3)和0.369 mg·m~(-3),细菌气溶胶浓度范围为4100～22 100 cfu·m~(-3),真菌气溶胶浓度范围为440～2480 cfu·m~(-3);保育舍内TSP、PM_(10)、PM_4、PM_(2.5)和PM_1平均质量浓度分别为1.284、0.572、0.271、0.245 mg·m~(-3)和0.230 mg·m~(-3),细菌气溶胶浓度范围为2120～6850 cfu·m~(-3),真菌气溶胶浓度范围为160～1110 cfu·m~(-3)。三种猪舍内细菌气溶胶浓度比较发现,妊娠舍最高,其次是分娩舍,保育舍最低;真菌气溶胶主要分布在粒径小于3.3μm的范围内。颗粒物与微生物气溶胶的相关性关系分析发现,真菌气溶胶和粒径小于1.1μm的细菌气溶胶可能是以孢子或者菌丝的形式独立漂浮于空气中。     

微生物发酵床不同深度垫料的细菌群落多样性

为了解微生物发酵床不同深度垫料细菌的多样性,明确不同深度的细菌群落组成,采用五点采样法,收集了发酵床表层10 cm、中层30 cm、深层50 cm的垫料,分别进行垫料宏基因组DNA的提取,原核生物16S rDNA基因V3～V4区的扩增及Illumina高通量测序。试验共获得1 045 225条序列,共包含32门、303科、609属和1834类OTUs。表层垫料细菌数量最多,中层垫料细菌种类最多。微生物发酵床不同深度垫料的细菌群落有所差异,在表层垫料中,变形菌门(25.9%)和放线菌门(10.2%)相对含量高;中层垫料中拟杆菌门(27.8%)、变形菌门(25.1%)和厚壁菌门(17.0%)相对含量高。发酵床垫料表层和中层细菌多为有机物降解菌,主要为异常球菌——栖热菌门的特吕珀菌科、变形菌门的黄单胞菌科和拟杆菌门的黄杆菌科细菌。随着垫料深度增加,拟杆菌门(33.3%)和螺旋体门(9.2%)含量升高,厌氧菌如螺旋体门的螺旋体科、拟杆菌门的腐螺旋菌科在深层垫料中达到峰值。研究表明,表层垫料中微生物含量最高,代谢最为活跃,是主要的有机质降解层;深层垫料厌氧菌含量高。     

整合微生物组菌剂的提出、研发与应用

【目的】利用微生物发酵床作为发酵槽,猪粪氮素连续流加中温好氧发酵,将通过宏基因检测鉴定到的微生物组称为整合微生物组,生产高含菌量整合微生物组菌剂,作为植物病害生防菌剂。【方法】生产工艺:原料配制→发酵床发酵→猪粪氮素连续流加→好氧发酵控制→产品加工→产品包装等。生产技术:利用养猪使用1年以上的微生物发酵床,添加一层10 cm厚的30%豆饼粉+70%杏鲍菇菌糠垫料,每平方米1头猪作为猪粪氮素连续流加营养来源,每天翻耕1次,连续好氧发酵20 d后,取出上层20 cm的垫料,进入晾晒、粉碎、分筛、包装,加工成整合微生物组菌剂。【结果】整合微生物组菌剂产品技术指标:含水量29.74%,pH 7.56,有机质含量44.46%,全氮含量2.23%,腐殖酸含量11.20%,粗纤维含量14.06%,含菌量145×10 ⁸cfu/g。宏基因组测定结果表明,菌剂样品序列（reads）条数平均值为99 701.75,每克菌剂含有细菌39门、96纲、189目、383科、786属、1 281种;其中,芽孢杆菌46种,9种为中国新记录种,即:①嗜气芽孢杆菌（Bacillus aerophilus）、②蚯蚓芽孢杆菌（Bacillus eiseniae）、③丝状芽孢杆菌（Bacillus filamentosus）、④柯赫芽孢杆菌（Bacillus kochii）、⑤根际芽孢杆菌（Bacillus rhizosphaerae）、⑥长型赖氨酸芽孢杆菌（Lysinibacillus macroides）、⑦淤泥大洋芽孢杆菌（Oceanobacillus caeni）、⑧拾蛤鸟氨酸芽孢杆菌（Ornithinibacillus scapharcae）、⑨海洋枝芽孢杆菌（Virgibacillus oceani）;未发现猪细菌病原。可培养法分离的芽孢杆菌活菌数2.062×10 ⁸cfu/g,宏基因组测定结果中,芽孢杆菌的总丰度为1.42%,以此推算菌剂有效细菌总含量145×10 ⁸cfu/g。整合微生物组菌剂浸出液处理组的绿豆发芽率为96.67%,与清水对照组无显著差异（P>0.05）,但胚根长比对照增加了58.08%。用5%—10%的菌剂配制成育苗基质,番茄出苗率提高了3.0%,株高增加了25.1%,对番茄青枯病的校正防治效果可达79.41%。整合微生物组菌剂的产品质量标准参考农业农村部生物有机肥标准（NY884-2012）,初步确定为:有机质≥40%,含水量≤30%,pH 5.5—7.5,粪大肠菌群数≤100个/g,蛔虫卵死亡率>95%,有效期>6个月;重金属含量满足标准要求:砷<15 mg·kg ^-1,镉≤15 mg·kg ^-1,铅≤15 mg·kg ^-1,铬≤15 mg·kg ^-1,汞≤15 mg·kg ^-1;有效活菌数调整为:总细菌数≥30×10 ⁸cfu/g,其中芽孢杆菌≥2×10 ⁸cfu/g。 【结论】提出了整合微生物组菌剂的概念和产品技术标准。研发的整合微生物菌剂可促进种子根部生长,并对番茄青枯病有良好的防治效果。