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1.
盖永霞 《畜牧兽医科学(电子版)》2021,(4):68-69
我国从古至今都是农业大国,在经济体制改革的推动下,我国工业发展迅猛的情况下,农业依旧是我国的产业支柱,对促进我国经济发展有极大帮助。养殖业是农业的重要部分,而养殖业中,鸡养殖有占据极大比例,且其规模也在不断扩大。近年,鸡的一些疾病发病率逐渐增加,其中细菌性腹泻是常见的1种,会影响鸡群身体健康与生长发育,甚至会导致其死亡,危害极大,给养殖户乃至养殖产业造成极大的经济损失,做好鸡细菌性腹泻预防与治疗工作尤为重要。该文对鸡细菌性腹泻的特点进行探讨,并提出一些防治措施。 相似文献
2.
为发掘对林木生长发育有利的优良微生物资源,并筛选适合叶表微生物的收集方法,以马尾松针叶为试验材料,分别用悬摇法和超声波法收集马尾松叶表微生物,用扩增子高通量测序技术、MUSCLE和Qiime软件研究马尾松叶表微生物的多样性。结果表明:扫描电镜观测结果显示,马尾松针叶表面定殖有大量微生物,包括真菌(菌丝及孢子)和细菌。扩增子高通量测序结果表明,马尾松叶表微生物物种丰富,包含细菌运算分类单位(OTUs)490个,真菌OTUs 1273个。马尾松叶表细菌以未分类的蓝细菌属(unidentified_Cyanobacteria)(36.53%)、未分类的拜叶林克氏菌属(unidentified_Beijerinckia)(28.60%)、鞘氨醇单胞菌属(Sphingomonas)(2.35%)为优势属;叶表真菌以枝孢属(Cladosporium)(2.45%)、拟盘多毛孢属(Pestalotiopsis)(0.92%)、无头孢菌属(Capnobotryella)(0.91%)为优势属。针对叶表细菌多样性的研究表明,悬摇法和超声波法均有较高的物种检出度;在叶表真菌多样性的研究中超声波法优于悬摇法,但超声波法样品间数据变异性较大,测定结果不稳定。 相似文献
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H. J. Schouten 《European journal of plant pathology / European Foundation for Plant Pathology》1989,94(4):213-220
The rate of multiplication of fire blight causing bacteriumErwinia amylovora (Burrill) Winslow et al. depends on the availability of water. Water availability can be quantified by means of the parameter water potential. The relationship between water potential and relative multiplication rate ofE. amylovora was derived from experiments of L. Shaw (1935). This relationship appears to be applicable toE. amylovora in plant tissues and in nectar of flowers.Multiplication and expansion ofE. amylovora in a restricted space, e.g. an intercellular hole, creates a pressure, which may cause schizogenic cavities in soft tissue. Strong tissue, however, may be able to resist this multiplication pressure of the bacteria, so that symptom progression can be prevented. A hypothesis is formulated on how the multiplication pressure may be quantified by means of the parameter water potential. Expansion of bacterial ooze may alo be due to absorbtion of water without increase of dry weight (e.g. a daily cycle of shrinkage and expansion). This expansion may give rise to a swelling pressure, which again may be quantified by means of the parameter water potential.Samenvatting De vermenigvuldigingssnelheid van de bacterie die bacterievuur veroorzaakt (Erwinia amylovora (Burrill) Winslow et al.,), hangt af van de beschikbaarheid van water. De beschikbaarheid van water kan worden gekwantificeerd met de parameter waterpotentiaal. De relatie tussen waterpotentiaal en relatieve vermenigvuldigingssnelheid vanE. amylovora werd afgeleid uit experimenten van L. Shaw (1935, Cornell University Agricultural Experiment Station, Ithaca. Memoir 181). Deze relatie kan zowel worden toegepast op de pathogenese in planteweefsel als op de epifytische ontwikkeling in nektar.Vermenigvuldiging vanE. amylovora in een beperkte ruimte, bijvoorbeeld in een intercellulaire holte, creëert een druk, die tot scheuren van zacht weefsel kan leiden. Sterk weefsel kan de vermenigvuldigingsdruk van de bacteriën vermoedelijk wel weerstaan, zodat uitbreiding wordt verhinderd. In een hypothese wordt beschreven hoe de vermenigvuldigingsdruk zou kunnen worden gekwantificeerd met behulp van de parameter waterpotentiaal. Wateropname door bacterieslijm zonder toename van het drooggewicht (bijvoorbeeld een dagelijkse gang van krimpen en zwellen) kan ook leiden tot een druk. Deze druk kan eveneens worden berekend met de parameter waterpotentiaal. 相似文献
6.
Atilla Dursun M. Figen Dönmez Fikrettin Şahin 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(8):811-813
Common bacterial blight (CBB) in edible beans (Phaseolus vulgaris), incited Xanthomonas campestris pv. phaseoli, reduces bean yields and seed quality. The main objective of this study was to determine resistance to common bacterial blight in bean genotypes. Twenty-two bean genotypes grown in Turkey including common and snap bean cultivars/lines were collected from different parts of Turkey and tested for resistance against to Xanthomonas campestris pv. phaseoli strain MFD-11. All the common and snap bean lines/cultivars tested were moderately susceptible, susceptible or highly susceptible, except AG-7117 which was found resistant to Xanthomonas campestris pv. phaseoli. This is the first report of a resistance source in a common bean line (AG-7117) against Xanthomonas campestris pv. phaseoli. 相似文献
7.
Xanthomonas campestris pv. vitians , the causal agent of bacterial leaf spot of lettuce (BLS), can be seedborne, but the mechanism by which the bacteria contaminates and/or infects lettuce seed is not known. In this study, the capacity of X. campestris pv. vitians to enter and translocate within the vascular system of lettuce plants was examined. The stems of 8- to 11-week-old lettuce plants were stab-inoculated, and movement of X. campestris pv. vitians was monitored at various intervals. At 4, 8, 12 and 16 h post-inoculation (hpi), X. campestris pv. vitians was recovered from 2 to 10 cm above (depending on stem length) and 2 cm below the inoculation site. Xanthomonas campestris pv. vitians was also recovered from surface-disinfested stem sections of spray-inoculated plants. Together, these results are consistent with X. campestris pv. vitians invading and moving systemically within the vascular system of lettuce plants. To investigate the mechanism of seed contamination, lettuce plants at the vegetative stage of growth were spray-inoculated with X. campestris pv. vitians and allowed to develop BLS. Seed collected from these plants had a 2% incidence of X. campestris pv. vitians external colonization, but no bacteria were recovered from within the seed. 相似文献
8.
Phenotypic and genetic characteristics of nine bacterial strains isolated from mulberry ( Morus spp.), which were originally described as Erwinia carotovora ssp. carotovora (Ecc), were investigated. Based on the results of biochemical tests, these bacterial strains were divided into two different types, type 1 and type 2. Two strains of type 1 were similar to Ecc, whereas seven strains of type 2 were distinct from Ecc. A polyphasic study that included serological assay, specific PCR assay for E. carotovora ssp. atroseptica (Eca), PCR-RFLP of a pectate lyase ( pel ) gene and RAPD-PCR was performed on the type 2 strains, and the data were compared with those of related E. carotovora subspecies. The results of serological and specific PCR assays for Eca showed that the type 2 strains were distinct from Eca. In RFLP analysis of the pel gene using Sau 3AI, the type 2 strains showed a unique RFLP pattern. On the basis of RAPD analysis, similarity of RAPD patterns within the type 2 strains was very high. A unique RAPD fragment was isolated from the type 2 strains and used as a probe for Southern hybridization. This probe hybridized only with PCR products from the type 2 strains. Based on phenotypic, serological and genetic characteristics, the type 2 strains isolated from mulberry may belong to a distinct E. carotovora subspecies other than Eca or Ecc. 相似文献
9.
引起糖甜菜细菌性叶斑病的萎蔫短小杆菌新致病变种 总被引:3,自引:0,他引:3
1995年在内蒙古临河市新发现了糖甜菜细菌性叶斑病,从病斑所分离的10个细菌菌株经柯赫氏法则验证,均确系该病的病原菌。采用形态观察、表型特征和生理生化特性测定、数值分析、血清学反应、细胞化学成分分析、DNA G+C mol%和DNA-DNA同源性测定进行了鉴定,并与植物病原棒形细菌15个标准菌株进行了比较。该病原菌为革兰氏阳性细菌,不规则短杆状,有一根鞭毛、亚极生或侧生,结合其生理生化特性、细胞化学成分和DNA G+C mol%和DNA-DNA同源性测定结果,认为应属于短小杆菌属(Curtobacterium)的萎蔫短小杆菌(Cur. flaccumfaciens),数值分析也支持这一结论。此外,据血清学反应结果及其对短小杆菌属的其它植物寄主的致病情况,认为该病原菌应是萎蔫短小杆菌种下的一个新的致病变种,定名为Curtobacterium flaccumfaciens pv. beticola pv. nov. Chen et al.,2000(萎蔫短小杆菌糖甜菜致病变种)。 相似文献
10.
Margareta Hökeberg Berndt Gerhardson Lennart Johnsson 《European journal of plant pathology / European Foundation for Plant Pathology》1997,103(1):25-33
About 400 bacterial strains, isolated from roots of wild and cultivated plants, were screened for effects against diseases caused by Drechslera teres and/or Microdochium nivale in greenhouse tests and against common bunt caused by Tilletia caries in field tests. Four of the strains showed good biocontrol activity <70% disease reduction) against D. teres and T. caries both in screenings and field tests. One Pseudomonas isolate, MA 342, strongly and reliably suppressed both D. teres and T. caries in the field, while effects against M. nivale were weaker. The effects could not be enhanced by varying pre-application or seed application procedures. This isolate could be stored as a suspension in a refrigerator, frozen or applied to seeds for at least one month without loosing its disease controlling ability. 相似文献