Since direct staining of growing hyphae with trifluoperazine (TFP) could result in the migration of protoplasm in hyphae of water mold Saprolegnia feraX, an improved staining method for fixation of growing hyphae was ...Since direct staining of growing hyphae with trifluoperazine (TFP) could result in the migration of protoplasm in hyphae of water mold Saprolegnia feraX, an improved staining method for fixation of growing hyphae was developed. When hyphae of Saprolegnia ferax were pre-fixed with paraformaldehyde, the TFP fluorescence showed a clear tip-high Ca(2+)-activated calmodulin (CaM) gradient. By indirect immunohistochemical staining, we proved that total CaM also mainly concentrated in the apex of hyphae.It is noticeble that when the hyphal tip growth ceased, the high intensity of TFP fluorescence usually disappeared in non-growing tips and became evident in the newly emerged growing tips, which implied that the concentration of CaM shifted in concord with the transfer of growing point in hyphae. 2×10(-5) mol/L CaM inhibitor TFP could reduce the tip growth rate and the percentage of growing hyphal tips to about 50%, and induce multibranching of hyphal tips. These findings strongly suggest that the high concentration of calmodulin in the hyphal tip may be involved in regulation of hyphal tip growth.展开更多
Based on the theory of biological control of Saprolegnia ferax,antagonism test of nine strains of Bacillus sp. to S. ferax JL was carried out. Bacillus sp.BA1 was screened to have significantly inhibitory effects on t...Based on the theory of biological control of Saprolegnia ferax,antagonism test of nine strains of Bacillus sp. to S. ferax JL was carried out. Bacillus sp.BA1 was screened to have significantly inhibitory effects on the growth of S. ferax JL( P 【 0. 05). Then,the effects of Bacillus sp. BA1 on different sources of S. ferax were carried out. Results showed that BA1 also had significantly inhibitory effects on S. ferax 6#,10# and S2( P 【 0. 05). Sequence of 16 S r DNA of BA1 was analyzed; and homologous alignment analysis showed that BA1 had more than 99% similarity with Bacillus cereus. Therefore,it could be concluded that strain BA1 was B. cereus,which significantly inhibited the growth of S. ferax and could be used as the biological control agent for S. ferax diseases in aquaculture.展开更多
文摘Since direct staining of growing hyphae with trifluoperazine (TFP) could result in the migration of protoplasm in hyphae of water mold Saprolegnia feraX, an improved staining method for fixation of growing hyphae was developed. When hyphae of Saprolegnia ferax were pre-fixed with paraformaldehyde, the TFP fluorescence showed a clear tip-high Ca(2+)-activated calmodulin (CaM) gradient. By indirect immunohistochemical staining, we proved that total CaM also mainly concentrated in the apex of hyphae.It is noticeble that when the hyphal tip growth ceased, the high intensity of TFP fluorescence usually disappeared in non-growing tips and became evident in the newly emerged growing tips, which implied that the concentration of CaM shifted in concord with the transfer of growing point in hyphae. 2×10(-5) mol/L CaM inhibitor TFP could reduce the tip growth rate and the percentage of growing hyphal tips to about 50%, and induce multibranching of hyphal tips. These findings strongly suggest that the high concentration of calmodulin in the hyphal tip may be involved in regulation of hyphal tip growth.
基金Supported by the Industry-Academia-Research Project of Guangdong Province(2010B090400002)Special Fund for Modern Agricultural Industry Technology System(NYCYTX-49-17)
文摘Based on the theory of biological control of Saprolegnia ferax,antagonism test of nine strains of Bacillus sp. to S. ferax JL was carried out. Bacillus sp.BA1 was screened to have significantly inhibitory effects on the growth of S. ferax JL( P 【 0. 05). Then,the effects of Bacillus sp. BA1 on different sources of S. ferax were carried out. Results showed that BA1 also had significantly inhibitory effects on S. ferax 6#,10# and S2( P 【 0. 05). Sequence of 16 S r DNA of BA1 was analyzed; and homologous alignment analysis showed that BA1 had more than 99% similarity with Bacillus cereus. Therefore,it could be concluded that strain BA1 was B. cereus,which significantly inhibited the growth of S. ferax and could be used as the biological control agent for S. ferax diseases in aquaculture.
文摘以水霉菌(Saprolegnia ferax)的生物防治为切入点,通过对本实验室保存的9株芽孢杆菌(Bacillus spp.)与水霉菌JL菌株进行对峙拮抗试验,筛选出具有明显抑制水霉菌JL菌株的芽孢杆菌BA1(P<0.05)。经进一步测定菌株BA1对不同来源水霉菌株试验,结果显示菌株BA1对水霉菌株6#、10#、S2也有明显的抑制作用(P<0.05)。通过测定菌株BA1的16 S rDNA,利用BLAST软件进行同源性比对,发现与蜡样芽孢杆菌的同源性在99%以上。由此推测,菌株BA1为蜡样芽孢杆菌菌株,且具有明显抑制水霉菌作用,可以作为水产养殖上水霉病防治的生物制剂使用。
