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为明确双组分系统FlrBC在嗜水气单胞菌极生鞭毛合成、生物被膜形成及致病机制中的作用,通过同源重组法,以嗜水气单胞菌ZYAH72为野生菌株构建双组分系统FlrBC缺失株ΔflrB和ΔflrC,比较不同菌株鞭毛合成及游动性、生物被膜形成、胞外多糖分泌、细胞黏附以及抗全血杀伤能力差异。结果显示:与野生株相比,ΔflrB和ΔflrC仍能形成极生鞭毛,细菌游动能力无显著差异;而结晶紫染色发现ΔflrB和ΔflrC相较于野生株的生物被膜形成能力分别下降了27.2%和22.3%;刚果红检测结果显示,与野生株相比,ΔflrB和ΔflrC的胞外多糖分泌分别下降了18.4%和14.2%;实时荧光定量PCR的结果显示,flrB和flrC的缺失不同程度抑制了鞭毛合成、生物被膜相关通路基因的表达;与草鱼肾细胞共孵育后,ΔflrB和ΔflrC的细胞黏附率与野生株相比分别下降了23.2%和18.2%;全血杀伤实验结果显示,ΔflrB和ΔflrC抗全血杀伤能力均显著减弱。以上结果表明,双组分系统FlrBC不是嗜水气单胞菌极生鞭毛形成所必需,但在细菌鞭毛形成组装和生物被膜形成中发挥调控作用,并且影响嗜水气单胞菌致病性... 相似文献
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Yugo Moraes Pastrana Danilo Pedro Streit Raycon Roberto Freitas Garcia Bruno Silveira Becker Jos Luiz Rodrigues Leandro Godoy 《Aquaculture Research》2019,50(2):521-528
Our study assessed the efficiency of a formulated new extender in maintaining viability and morphological integrity of Colossoma macropomum spermatozoa under chilling storage. Semen was diluted in the test extender and BTS? (Beltsville Thawing Solution) and exposed to a short‐term storage at 4.6 ± 0.6°C for 96 hr. Both extenders were able to maintain 17% ± 8% motile spermatozoa by the end of experiment. Sperm dilution in test extender did not affect the morphologically normal cells (61% ± 6%) up to 48 hr of chilling, being higher than in BTS? (50% ± 6%) (p < 0.05). After 96 hr, samples kept in the test extender had 50% of normal spermatozoa, whereas those kept in BTS? presented only 38% of normal cells. Chilling storage increased the incidence of cells with strongly coiled flagella in BTS?. Our study is the first to evaluate in detail the spermatozoa morphology as indicative of C. macropomum semen viability. The new extender was able to protect the spermatozoa against increase in coiled flagellum injuries. 相似文献
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Md. Tofazzal ISLAM Toshiaki ITO Satoshi TAHARA 《Journal of General Plant Pathology》2002,68(2):111-117
The mode of aggregation, attachment and differentiation of zoospores of the phytopathogenic fungus Aphanomyces cochlioides when interacting with the host and a host-specific attractant and a G-protein activator, mastoparan, was studied by light
and scanning electron microscopy. When a zoospore approached very close to the host root, it seemed to halt, then coiled its
anterior flagellum on its body. The halted zoospore appeared to contact the host surface with its posterior flagellum, which
gradually drew the encysting zoospore onto the root surface. The spore then docked precisely on the root surface at its ventral
face with the help of the posterior flagellum and anchored itself by releasing some adhesive materials. The adherent spore
became a spherical after shedding its flagella and rapidly turned into an expanded cyst forming a smooth cyst coat around
it, and finally changed into a smaller cystospore covered with a wrinkled surface. In contrast, the mastoparan- or cochliophilin
A-stimulated zoospores on artificial membranes aggregated by using their posterior flagella before encystment. These contrasting
phenomena suggest that A. cochlioides zoospores may use their posterior flagella for successful docking on the host surface or for aggregation of encysting spores
in the absence of the host.
Received 30 August 2001/ Accepted in revised form 8 November 2001 相似文献
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Teruyoshi Narita Takayuki Kawamoto Kiyoshi Isowa Hideo Aoki Masahiro Hayashi Hiromi Ohta Akira Komaru 《Fisheries Science》2008,74(5):1069-1074
To clarify factors reducing the motility and fertility of cryopreserved spermatozoa of the Japanese pearl oyster Pinctada fucata martensii, the structure of spermatozoa before and after cryopreservation was observed by scanning electron microscopy. Testicular
spermatozoa were diluted with cryopreservation diluent (10% methanol+18% fetal bovine serum+72% sea water), and dispensed
into 0.25-mL straws. The straws were cooled at a rate of approximately −20 °C/min to −50°C, and subsequently immersed in liquid
nitrogen. Percentage motility of spermatozoa before cryopreservation was 69.9±4.2%, and that of cryopreserved spermatozoa
was 24.0±1.8%, respectively. In cryopreserved spermatozoa, the percentage that lacked or had a deformed flagellum was 56.6±3.9%,
while in fresh spermatozoa this was 8.7±2.0%. In cryopreserved spermatozoa, the percentage of deformed acrosomes was 76.6±5.2%,
while in fresh spermatozoa this was only 0.9±0.3%. Cryopreserved spermatozoa with a normal acrosome and flagellum were only
15.4±3.5% of those in fresh spermatozoa. These results indicate that lesion of the flagellum and deformation of the acrosome
occurred through the cryopreservation procedure, and both types of damage lead to loss of the motility and fertility in thawed
spermatozoa. 相似文献
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河北昌黎与广西资源两地区葡萄霜霉菌致病力分化分析 总被引：1，自引：0，他引：1
为明确河北昌黎、广西资源两地不同葡萄品种来源霜霉菌致病力分化情况,本研究利用离体叶盘接种法测定了河北、广西主栽品种‘红宝石无核’、‘红地球’及‘巨峰’来源葡萄霜霉病菌对不同鉴别寄主的致病力,观察不同地区、不同寄主来源病菌对同一感病材料以及同一寄主来源病菌对不同感病材料的致病力大小是否存在差异。结果表明:不同地区同一寄主来源病菌及同一来源不同菌株间致病力均存在差异,说明两个地区病菌群体间和群体内各菌株间均存在分化;两地不同寄主来源病菌群体对同一感病材料的致病力及同一寄主来源病菌群体对不同感病材料的致病力均存在显著差异,且广西资源地区菌株间差异性比河北昌黎地区更明显,说明不同寄主来源的菌株存在一定程度的分化。 相似文献
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Effect of water temperature on the physiology of fish spermatozoon function: a brief review 
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下载免费PDF全文 Hadiseh Dadras Borys Dzyuba Jacky Cosson Amin Golpour Mohammad Abdul Momin Siddique Otomar Linhart 《Aquaculture Research》2017,48(3):729-740
Motility is a key factor in function of the spermatozoon and determines semen quality and fertilizing capacity. Effective motility occurs when sperm is diluted in a swimming solution, the adequacy of which is determined by factors varying according to fish species. Spermatozoon motility rate and velocity, as well as duration of the motility period, are influenced by the temperature of the water in which broodfish are held. Increase in temperature of swimming medium beyond the optimal increases cell metabolism, leading to an increase in velocity with rapid depletion of energy resources, promoting early cessation of movement. The aim of this review was to discuss current information on the influence of temperature on quantitative spermatozoon properties, which could affect sperm function. Our findings provide a greater understanding of fish sperm physiology and a biological foundation for the further development of spermatozoon motility investigations as well as reproduction technologies. 相似文献
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