生物有机液体混合肥对甜高粱根系形态特征的影响

为揭示生物液体有机混合肥对陕北农牧交错区青贮饲草作物根系形态特征的影响,通过盆栽控制试验,以甜高粱(Sorghum bicolor L.)为材料,设置不同浓度的生物活性水(BMW)(B1、B2、B3和B4)和Aidoora溶液(A1、A2和A3)处理,并测定甜高粱幼苗期的根系形态特征。结果表明:在大多数单一液体肥和混合液体肥下,甜高粱的根系生物量(RB)、根冠比(RSR)、根系体积(RV)、总根长(TRL)、根系表面积(RSA)、平均根直径(RAD)、比根长(SRL)和比根面积(SRA)均显著高于CK,表明BMW和Aidoora溶液有利于促进甜高粱苗期根系生物量积累和根系吸收能力;甜高粱的RB、TRL和RSA两两间均呈明显的正相关关系,表明根系表面积和总根长均随着根系生物量的升高而增加。综上分析表明,B3A2和B3A3相对于其他BMW和Aidoora混合液体肥,有利于促进甜高粱幼苗根系生物量积累和根系形态建成。     

Analysis of Inter-Individual Bacterial Variation in Gut of Cicada Meimuna mongolica (Hemiptera: Cicadidae)

Intestinal bacterial community plays a crucial role in the nutrition, development, survival, and reproduction of insects. When compared with other insects with piercing-sucking mouthparts, the habitats of cicada nymphs and adults are totally different. However, little is known about the differences in the gut bacterial communities in the nymphs and adults within any cicada species. The diversity of bacteria in the gut of nymphs and adults of both genders of Meimuna mongolica (Distant) was studied using the denaturing gradient gel electrophoresis (DGGE) method. Few inter-individual variations among gut microbiota were observed, suggesting that M. mongolica typically harbors a limited and consistent suite of bacterial species. Bacteria in the genera Pseudomonas and Enterobacter were the predominant components of the gut microflora of M. mongolica at all life stages. Bacteria of Pantoea, Streptococcus, and Uruburuella were also widespread in the cicada samples but at relatively lower concentrations. The relative stability and similarity of the PCR-DGGE patterns indicate that all individuals of this cicada species harbor a characteristic bacterial community which is independent from developmental stages and genders. Related endosymbionts that could be harbored in bacteromes of cicadas were not detected in any gut samples, which could be related to the cicada species and the distribution of these endosymbionts in the cicada cavity, or due to some of the possible limitations of PCR-DGGE community profiling. It is worthwhile to further address if related cicada endosymbiont clades distribute in the alimentary canals and other internal organs through diagnostic PCR using group-specific primer sets.     

Genome-wide Association Study of Teats Number Traits in Kele Pigs

Teats number is one of the most important reproductive traits,and closely related to the economic benefit in pig industry.In order to reveal the underlying genetics of left teats number,right teats number and total teats number traits,a genome-wide association study（GWAS）was performed.Samples of DNA were collected to genotyping for 22 Kele pigs using the Illumina Porcine SNP 60K Chip.The GWAS was performed using a mixed-effects model and linear regression approach.When a genome-wide threshold was determined using the Bonferroni method（P<2.06E-5),4 single nucleotide polymorphism（SNP）markers were potentially associated with left teats number,right teats number and total teat number.However,3 SNPs were significant associated and 18 SNPs were potentially associated in chromosomes level.304 Ensembl genes were retrieved around 1 cM of the associated SNPs.The candidate genes in Wnt and Fgf signaling pathway（BTRC,FGF5,FGF8,BMP3,RASGEF1B and HMGB3）might have effect on target traits.These results provided valuable information about the selective breeding for Kele pigs.     

Systematic evaluation of in-house broiler litter windrowing effects on production benefits and environmental impact

In-house windrowing of broiler litter between flocks has been adopted by producers to reduce pathogens and improve litter quality before chick placement. In this study, 5 consecutive windrow trials were conducted in commercial broiler houses for their effect on litter bacterial populations, organic matter stabilization, cumulative ammonia emissions, and nutrient transformation and compared with litter conditioning (tilling) in adjacent houses. No significant reduction ofClostridium spp. andEscherichia coli populations was found in windrowed litter from d 0 to 7. No significant difference of 7-d mortality was found between windrow and nonwindrow houses. The windrowed house resulted in better foot quality than the nonwindrowed house from 1 of 3 scored flocks. Water-soluble phosphorus increased in both windrowed and nonwindrowed litter; therefore, appreciable biotic and abiotic activity occurred in litter with both treatments after flocks were removed. Overall, no negative effect of windrow treatments on litter quality for agronomic applications was observed. Both the control and windrow treatments resulted in a decrease in litter moisture content (2 to 5%) likely beneficial to bird health conditions. High ammonia emissions persisted after windrow spreading; therefore, a need may exist for an extended period of ventilation or a litter amendment as crucial before chick placement. Litter amendment at a low dose was effective in lowering ammonia concentrations after windrowing and was more economical comparing to operating fans in winter conditions.     

秸秆纤维素分解细菌的筛选与鉴定

利用纤维素琼脂选择培养基和刚果红染色方法,从不同来源的土样中分离出2个菌株,测定了其纤维素酶活性、小麦秸秆降解能力,并对纤维素降解能力强的两个菌株进行了分子鉴定。结果表明,两株高效纤维素分解菌在纤维素刚果红培养基上均能形成透明水解圈,利用16S r RNA序列测序并分析Genbank中的同源性,结合形态和理化性质确定为Bacillus thuringiensis和Bacillus anthracis。在37℃,p H为7的条件下测定了纤维素酶活力,SC1-3和XR2-5-4分别为1.41和1.59。这两株37℃下经15 d后小麦秸秆失重率达19.92%和22.83%。     

新疆核桃腐烂病拮抗菌的筛选及鉴定

为给核桃促生菌群的构建提供菌株材料,通过对新疆核桃拮抗菌的分离纯化,筛选出对核桃腐烂病病原菌具有拮抗作用且能在其根际稳定定殖的优质高效菌株。从阿克苏、和田、喀什等新疆核桃主产区的根际土壤中分离出拮抗菌30株,采用对峙试验法对其拮抗能力进行测定,选出拮抗菌14株。经耐利福平诱导后剩余7株。将其进行大田定殖试验后,最终筛选出7株拮抗菌。经16S r DNA鉴定,这7株拮抗菌属于3个属,分别为假单胞菌属Pseudomonas、芽孢杆菌属Bacillus、链霉菌属Streptomyces,其中假单胞菌属为优势种属,且拮抗效果及稳定性最好。     

葡萄枝叶自然青贮中优选乳酸菌的分离与鉴定

本研究旨在对葡萄枝叶青贮饲料中天然附着优势乳酸菌进行分离培养和鉴定,为葡萄枝叶资源的饲料化利用提供可靠的乳酸菌资源。利用分子生物学鉴定法(16S rDNA序列分析)与传统的微生物鉴定法对分离出的乳酸菌进行鉴定,最终得到5株乳酸菌菌株,其中Q1菌株鉴定为肠膜明串珠菌(Leuconostoc mesenterica),Q2和Q5菌株鉴定为屎肠球菌(Enterococcus faecium),Q3菌株鉴定为铅黄色肠球菌(Enterococcus casseliflavus),Q4菌株鉴定为海氏肠球菌(Enterococcus hirae)。所筛选出的乳酸菌除L.mesenterica在pH为9时不能生长,其余菌株均能在pH 3～9,4℃～45℃,3%和6.5% NaCl浓度环境下生长;其中E.hirae菌株在培养至24 h后其菌液pH可达到4.11,OD值为1.42,表现出最强的生长及产酸能力。     

高寒草甸植物根际溶磷菌的筛选鉴定及其溶磷与促生效果

为获得高寒草甸根际土中优良溶磷菌资源,本研究从青海省高寒草甸根际土中筛选了4株溶磷菌,结合16S rRNA基因分析法确定其分类地位,并通过钼锑抗比色法和盆栽试验进行了溶磷与促生效果的研究。结果显示：4株溶磷菌均为假单胞菌属(Pseudomonas sp.),均可形成明显的溶磷圈。在无机磷液体培养基中培养7d后,4株菌株的磷增量在156.17~511.33μg·mL^-1之间;溶磷过程中4株菌均分泌多种有机酸,总有机酸量在522.36~986.69mg·L^-1之间;盆栽试验表明4株菌均能显著增加披碱草(Elymus dahuricus Turcz.)株高和地上部干重;菌株MXSC5,MXSC6和MQC13可使植株全氮、全磷含量增加,且4株菌株对土壤速效氮、速效磷含量也有正向影响。本研究结果将有助于进一步探究溶磷菌对植物的促生作用及微生物菌肥的开发利用。     

‘晋农1号’达乌里胡枝子根瘤内生解磷菌的鉴定及特性研究

根瘤内生解磷菌具有促进豆科植物结瘤固氮,提高植物抗逆性等作用。本研究以‘晋农1号’达乌里胡枝子(Lespedeza daurica ‘Jinnong NO.1’)为试验材料,采用“划线法”分离其根瘤内生菌,筛选具有解磷能力的菌株,测定其解磷能力,并对其抗逆和促生特性进行研究。结果表明：达乌里胡枝子根瘤中共分离出88株内生菌,其中11株具有解磷能力;TG41,TG43,TG47和TG68解有机磷量为0.73~1.29μg·mL^-1,TG47和TG68解无机磷量为72.97和1.29μg·mL^-1,为有效解磷菌;经鉴定,TG41和TG43为Bacillus zanthoxyli,TG47为Phyllobacterium zundukense,TG68为Pantoea agglomerans;TG41,TG43和TG68在盐浓度0.01%~9.00%和pH4~pH12条件下均可生长;4株菌不耐高温,TG47和TG68能在4℃生长;TG41,TG43和TG68能分泌铁载体和有机酸。综上,达乌里胡枝子根瘤中存在丰富的内生菌,部分具有解磷功能、抗逆和促生潜力,可用于研发适合黄土高原地区胡枝子建植的根瘤微生物复合菌剂。     

犬猫皮肤病细菌性病原分离鉴定及天然产物抑菌效果分析

【目的】 分离鉴定武汉市患皮肤病犬猫细菌性病原,并探索其对传统抗菌药物与天然活性产物藤黄酸(GA)和6-溴靛玉红-3’-肟(BIO)的敏感性。【方法】 对患皮肤病犬猫采样并分离病原,通过生长特性观察、革兰氏染色镜检、PCR等方法鉴定并利用SPF小鼠验证致病性;通过药敏纸片验证其对传统药物的耐药性,并测定天然产物对其最小抑菌浓度(minimum inhibitory concentration,MIC)值。【结果】 分离得到2株金黄色葡萄球菌、3株伪中间型葡萄球菌、2株猫葡萄球菌、1株犬链球菌及1株奇异变形杆菌。SPF小鼠皮肤创伤感染验证分离菌株均有致病性。犬链球菌及奇异变形杆菌对各自受试药物均敏感;葡萄球菌对复方新诺明、青霉素、红霉素、四环素、左氧氟沙星、苯唑西林、庆大霉素、克林霉素及氯霉素存在不同程度耐药。天然活性产物GA和BIO对上述9株菌均具有良好抑菌效果,且除分离菌株F5外GA对分离菌株的MIC值均小于BIO。【结论】 本研究共分离得到5种、9株犬猫皮肤细菌。犬链球菌、奇异变形杆菌对传统抗菌药物均敏感,部分葡萄球菌存在耐药。GA和BIO对犬猫皮肤病原菌均有明显抑菌活性,显示其可作为防控犬猫细菌性皮肤病的候选药物。