The mechanisms determining the nucleolar-organizing regions inactivation of domestic horse chromosomes     

E. Slota  M. Wnuk  M. Bugno  A. Pienkowska-Schelling  C. Schelling  A. Bratus  & Z. Kotylak 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2007,124(3):163-171

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Reclassification of an isolate of Guignardia citricarpa from New Zealand as Guignardia mangiferae by sequence analysis   总被引：3，自引：0，他引：3  

K. R. Everett  J. Rees-George 《Plant pathology》2006,55(2):194-199

Citrus black spot was recorded as present in New Zealand in international databases on the basis of one isolate (ICMP 8336) identified by morphological features as Guignardia citricarpa . This isolate was from a soft rot, not a typical symptom of citrus black spot, on a Seminole tangerine fruit grown in the northern region of New Zealand. Sequence analysis of the internal transcribed spacer (ITS) region (ITS1, 5·8S and ITS2) showed that this isolate was 99% identical to the ITS region of G. mangiferae , a closely related saprotroph. Despite climatic conditions being suitable for this disease, citrus black spot symptoms have never been seen on citrus fruits grown in New Zealand. Thus the absence of symptoms on citrus in New Zealand is probably because G. citricarpa is not present. On the basis of these results, the record of citrus black spot occurring in New Zealand should be re-examined.  相似文献   

Genetic, phenotypic and pathogenic diversity among xanthomonads isolated from pistachio (Pistacia vera) in Australia     

A. Marefat  E. S. Scott  K. Ophel-Keller  M. Sedgley 《Plant pathology》2006,55(5):639-649

Repetitive extragenic palindromic polymerase chain reaction (rep-PCR), sequencing of the 16S−23S rDNA internal transcribed spacer (ITS), biochemical and physiological tests, the Biolog microplate system, polyacrylamide gel electrophoresis (PAGE) of whole-cell proteins, and pathogenicity tests were used to characterize variability among xanthomonads isolated from pistachio trees suffering from bacterial dieback in four regions of Australia. ITS sequencing and rep-PCR revealed two distinct genotypes among the strains. The ITS sequencing suggested that the pistachio strains were closely related to Xanthomonas translucens pathovars, in particular X. translucens pv . poae . Results of physiological and biochemical tests, as well as Biolog microplate analysis and protein profiling, confirmed the existence of two groups. Furthermore, pathogenicity and host-range studies indicated that the two groups were biologically different. There was an association between the two groups and the geographical origin of the strains.  相似文献   

斑点叉尾鲴嗜麦芽寡养单胞菌的分离鉴定及系统发育分析     

耿毅汪开毓  陈德芳黄小丽 《中国兽医学报》2007,27(3):330-335

从发生在四川、重庆等省市的斑点叉尾妇急性流行性传染病病鱼的肝脏、肾脏内分离到1株高致病性菌株（CCF00024），人工感染健康鱼表现出与自然痛鱼相同的症状，并从中分离获得同种细菌，证实其为斑点叉尾鲴急性流行性传染病的病原菌。形态、生理生化检测表明，该菌为非发酵型直杆菌，严格需氧，革兰氏阴性，极生多鞭毛，对除麦芽糖和甘露糖以外的多种糖类不利用产酸，氧化酶阴性，DNA酶、蛋白酶、脲酶、赖氨酸脱羧酶阳性，MR、VP阴性。在以该菌16SrDNA序列（GenBank登录号AY970826）和GenBank及RDP数据库内同源性较高的细菌16SrDNA序列构建的系统发育树中，分离菌CCF00024与嗜麦芽寡养单胞菌（Stenotrophomonasmaltophilia）聚在一簇，特剐是与5．maltophiliaM5—1的同源性最高，序列相似性达99．6％，结合形态和生理生化特点将其鉴定为嗜麦芽寡养单胞菌（Stenotrophomonasmaltophilia）。药敏试验结果表明，对磺胺甲口恶唑、磺胺异口恶唑、阿齐霉素、洛美沙星高度敏感，而对新霉素、卡那霉素、氨苄青霉素、头孢唑啉、先锋霉素V和链霉素不敏感。  相似文献   

Genotypic and phenotypic characterization of lactic acid bacteria isolated from Italian ryegrass silage     

Masanori TOHNO  Hisami KOBAYASHI  Masaru NOMURA  Maki KITAHARA  Moriya OHKUMA  Ryuichi UEGAKI  Yimin CAI 《Animal Science Journal》2012,83(2):111-120

Twenty-three lactic acid bacteria (LAB) isolated from three cultivars (Akiaoba, Nagahahikari and Tachiwase) of Italian ryegrass (Lolium multiflorum Lam.) silage were precisely characterized by a combination of phenotypic tests, genotypic 16S ribosomal DNA sequencing and rapid PCR-based analyses, focusing on their useful phenotypes for silage preparation as inoculants. We successfully identified both at the species and subspecies levels: phenotypically novel Lactococcus lactis subsp. lactis, Lactobacillus brevis, Lactobacillus coryniformis subsp. torquens, Lactobacillus curvatus, Lactobacillus plantarum subsp. plantarum, Lactobacillus sakei subsp. carnosus, Leuconostoc mesenteroides subsp. dextranicum and Pediococcus parvulus. This is the first report to elucidate the presence of Lactobacillus coryniformis ssp. torquens and Leuconostoc mesenteroides subsp. dextranicum in Italian ryegrass silages. Physiological and biochemical tests revealed that phenotypic characteristics are different among the different strains of the same species and subspecies, and that the isolates show unique and diverse phenotypes related to fermentation factors, such as available carbohydrates, optimal growth pH and temperature. These results suggest that, for various well-preserved silage preparations, the isolates may be useful in producing novel inoculants corresponding to their optimally climatic and ecological niches.  相似文献   

赤潮研究中圆海链藻实时荧光定量PCR检测方法的建立   总被引：3，自引：0，他引：3  

何闪英  吴小刚 《水产学报》2007,31(2):193-198

为建立快速、准确的鉴定和定量检测赤潮生物的方法,以圆海链藻为例，以其18S rDNA序列为寻找种特异性引物的靶区域，通过分析18S rDNA序列，设计出适合用于RFQ-PCR的引物与探针，并通过引物PCR验证确定其特异性，进而以圆海链藻荧光定量PCR的引物和探针（Primer Thalassiosira rotula和Taqman Thalassiosira rotula），建立了定量检测圆海链藻的实时荧光定量PCR检测方法（RFQ-PCR）。与传统的显微镜计数方法比较，两者所获结果无显著性差异，证明了本方法的可行性，从而为我国沿海水域赤潮问题的研究提供了良好的技术检测途径。  相似文献   

Molecular evidence for cosmopolitan distribution of platyhelminth parasites of tunas (Thunnus spp.)     

Hamish M Aiken  Nathan J Bott  Ivona Mladineo  Francisco E Montero  Barbara F Nowak  & Craig J Hayward 《Fish and Fisheries》2007,8(3):167-180

Global distribution of platyhelminth parasites and their host specificities are not well known. Our hypothesis was that platyhelminth parasites of large pelagic fishes are common around the world. We analysed molecular variation in three different taxa of platyhelminth parasites infecting four species of tunas: yellowfin tuna (Thunnus albacares, Scombridae) from Western Australia, southern bluefin tuna (Thunnus maccoyii, Scombridae) from South Australia, Pacific bluefin tuna (Thunnus orientalis, Scombridae) from Pacific Mexico and northern bluefin tuna (T. thynnus, Scombridae) from two localities in the Mediterranean (Spain and Croatia). Comparisons of ITS2 and partial 28S rDNA demonstrated two congeneric species of blood flukes (Digenea: Sanguinicolidae) from multiple hosts and localities: Cardicola forsteri from southern bluefin and northern bluefin tunas, and Cardicola sp. from Pacific bluefin and northern bluefin tunas; and a gill fluke, Hexostoma thynni (Polyopisthocotylea: Hexostomatidae), from yellowfin, southern bluefin and northern bluefin tunas. Partial 28S rDNA indicates that a second type of fluke on the gills, Capsala sp. (Monopisthocotylea: Capsalidae), occurs on both southern bluefin and Pacific bluefin tunas. This appears to be the first report of conspecific platyhelminth parasites of teleosts with a wide‐ranging geographical distribution that has been confirmed through molecular approaches. Given the brevity of the free‐living larval stage of both taxa of flukes on the gills (H. thynni and Capsala sp.), we conclude that the only feasible hypothesis for the cosmopolitan distribution of these flatworms is migrations of host tunas. Host migration also seems likely to be responsible for the widespread occurrence of the two species of blood flukes (Cardicola spp.), although it is also possible that these were translocated recently by the spread of infected intermediate hosts.  相似文献   

大连湾和辽东湾夏季海水细菌多样性16S rDNA分析     

赫崇波  丛林林  高祥刚  仲禾  姜北  邓欢 《水产科学》2008,27(9)

通过构建大连湾(DL17)和辽东湾(ZD-LDW017)2个站点夏季海水的细菌16s rDNA文库,利用16S rDNA序列比对法,对大连湾和辽东湾夏季海水细菌多样性进行了分析.试验结果表明,这2个海域的细菌主要为非培养细菌.每个海区分别随机选取了200个克隆进行酶切谱型分析和序列测定,共得到104个不同的DNA序列,其中大连湾51个序列,分别属于13种(属);辽东湾53个序列,分别属于13种(属).有6种菌为这2个海区所共有,这2个海区各自有不同的优势菌,且均未检测到致病菌,研究结果表明大连湾和辽东湾海水细菌具有丰富的多样性.  相似文献   

莱航鸡rDNA重复基因家族的克隆     

唐冬生  李芳  张勇  蒋泓  胡大林  张细权  李月琴  周天鸿 《中国家禽》2007,29(3):13-16

动物rDNA基因是一种GC含量较高、结构复杂的重复序列。通过结合生物信息学技术,经反复摸索后选用LAPCR法扩增莱航鸡rDNA基因重复序列,经测序鉴定最终克隆了莱航鸡的3个rDNA基因及其2个间隔序列。研究对克隆复杂DNA序列时引物设计的特别规则、反应体系的改进、DNA聚合酶的选用、循环参数的调整等进行了探索。  相似文献   

生草对关中地区有机猕猴桃园土壤养分及细菌群落的影响   总被引：1，自引：0，他引：1  

靳旭妹  王莹莹  刘崇义  陈新义  龙明秀  何树斌 《草业学报》2022,31(10):53-63

为探究不同生草模式对关中地区有机猕猴桃园土壤养分及细菌群落的影响,试验设置多年生黑麦草+毛苕子（Mode 1）、多年生黑麦草+草木樨（Mode 2）、多年生黑麦草+白三叶（Mode 3）及鼠茅草（Mode 4）,以自然生草处理为对照（CK）,观察草种生长特性、研究生草对果园耕层（0~20 cm）土壤养分影响,采用高通量测序法分析细菌群落结构。结果表明：鼠茅草越冬率最高,样地杂草株数最少。人工生草较自然生草有机质提高了6.46%~38.63%,以多年生黑麦草+毛苕子效果更为明显,且该处理提高土壤脲酶、蔗糖酶和碱性磷酸酶活性最为显著,分别为3.37、44.17和3.46 mg·d^-1·g^-1。同时,与自然生草相比,多年生黑麦草+毛苕子、多年生黑麦草+草木樨和多年生黑麦草+白三叶提高了土壤细菌群落的丰富度和多样性,多年生黑麦草+毛苕子存在最多差异显著的细菌分支。综上,关中地区有机猕猴桃园种植多年生黑麦草+毛苕子在一定程度上有助于提高土壤有机质及养分含量,改善土壤微生态环境。  相似文献