鳜早期发育阶段骨骼肌纤维的增生与肥大生长

骨骼肌是鱼体的主要组成部分,也是衡量鱼体生长发育的重要指标.为了解鳜(Siniperca chuatsi)早期发育阶段骨骼肌纤维的生长发育特征,通过制作孵化后1 ～41日龄个体骨骼肌背右侧第一肌节石蜡切片,利用图像分析软件统计该肌节中肌纤维的数目和面积,分析了鳜骨骼肌纤维的增生和肥大生长特征.结果表明,鳜早期发育阶段骨...     

碱度胁迫对尼罗罗非鱼鳃离子细胞形态以及鳃、肾和肠中HCO3-转运因子的影响

采用扫描电镜观察了不同碱度(0、2、4 g/L Na HCO_3)胁迫对尼罗罗非鱼(Oreochromis niloticus)鳃离子细胞形态变化的影响,并采用免疫组化技术观察了鳃、肾、肠中4个HCO_3~-转运因子碳酸酐酶(CAⅡ、CAⅣ)、碳酸氢钠协同转运载体(SLC4A4)、Cl~-/HCO_3~-离子交换体(SLC26A6)的阳性反应变化。扫描电镜结果表明,鳃离子细胞分布在鳃小片基部。根据其表面开孔形状和尺寸,可分为Ⅰ型、Ⅱ型、Ⅲ型和Ⅳ型4种亚型,各亚型离子细胞的开孔尺寸随碱度胁迫强度增高呈正比增大,Ⅲ型离子细胞开孔尺寸变化最明显(P0.01);离子细胞总数目也随碱度升高而增加,Ⅲ型离子细胞数目上升最为显著(P0.01)。免疫组化结果表明,在淡水、碱水组中,CAⅡ、CAⅣ、SLC4A4、SLC26A6在鳃小片基部和肾中均有阳性反应,且随着碱度升高,阳性反应增强,但在肠道中未观察到阳性反应。本研究结果初步表明,尼罗罗非鱼可通过鳃离子细胞形态和数量调节适应碱度变化,鳃和肾为主要应答调节器官。     

Low cytoplasmic pH reduces ER-Golgi trafficking and induces disassembly of the Golgi apparatus

The Golgi apparatus was dramatically disassembled when cells were incubated in a low pH medium. The cis-Golgi disassembled quickly, extended tubules and spread to the periphery of cells within 30 min. In contrast, medial- and trans-Golgi were fragmented in significantly larger structures of smaller numbers at a slower rate and remained largely in structures distinct from the cis-Golgi. Electron microscopy revealed the complete disassembly of the Golgi stack in low pH treated cells. The effect of low pH was reversible; the Golgi apparatus reassembled to form a normal ribbon-like structure within 1–2 h after the addition of a control medium. The anterograde ER to Golgi transport and retrograde Golgi to ER transport were both reduced under low pH. Phospholipase A₂ inhibitors (ONO, BEL) effectively suppressed the Golgi disassembly, suggesting that the phospholipase A₂ was involved in the Golgi disassembly. Over-expression of Rab1, 2, 30, 33 and 41 also suppressed the Golgi disassembly under low pH, suggesting that they have protective role against Golgi disassembly. Low pH treatment reduced cytoplasmic pH, but not the luminal pH of the Golgi apparatus, strongly suggesting that reduction of the cytoplasmic pH triggered the Golgi disassembly. Because a lower cytoplasmic pH is induced in physiological or pathological conditions, disassembly of the Golgi apparatus and reduction of vesicular transport through the Golgi apparatus may play important roles in cell physiology and pathology. Furthermore, our findings indicated that low pH treatment can serve as an important tool to analyze the molecular mechanisms that support the structure and function of the Golgi apparatus.     

萨罗罗非鱼AQP3 cDNA序列克隆及盐度胁迫下组织表达特征

利用cDNA末端快速扩增法(RACE)克隆了萨罗罗非鱼(Sarotherodon melanothern)鳃组织中水通道蛋白3(AQP3)的cDNA序列。AQP3 cDNA全长1894 bp,其中,开放阅读框912 bp,编码303个氨基酸,5'和3'非编码区长度分别为98 bp和884 bp。氨基酸序列分析显示,萨罗罗非鱼AQP3与莫桑比克罗非鱼(Oreochromis mossambicus)同源性最高,达94%,含6个跨膜区。应用实时荧光定量PCR技术(qRT-PCR)检测了不同盐度胁迫下萨罗罗非鱼11种组织中AQP3 mRNA的相对表达水平。0、15盐度下,鳃、肌肉、皮肤中表达水平相对较高,其他组织表达相对较低,且15盐度中各组织的表达水平低于0盐度;30盐度下,各组织以肠道表达量相对最高。推测在不同的渗透压调节作用中,萨罗罗非鱼通过不同组织器官中AQP3来参与水的转运过程。     

鳜慢肌胚后发育与生长特征

鱼类快肌和慢肌分别占据骨骼肌的不同位置,表现不同的生长发育特征。为了解鳜(Sinipercachuatsi)慢肌纤维的胚后发育特征,本研究通过制作孵化后1～33日龄鳜个体的石蜡切片,采用慢肌特异抗体的免疫组织化学染色,观察了背鳍起点处躯干横切面慢肌的发育变化特征,并利用图像分析软件统计慢肌纤维的数目和面积。结果表明,孵化后鳜仔鱼慢肌位于水平肌隔附近,呈楔形,向背、腹两侧生长。孵化后1～9日龄为单层肌纤维,11日龄发育为多层肌纤维,19日龄覆盖侧线附近,33日龄延伸至背侧第2背肌节、腹侧腹部肌肉2/3处,并在水平肌隔和侧线处分别形成两个肌群。位于骨骼肌最外层的扁平状表层细胞,可能为慢肌增生生长的主要来源。躯干单侧慢肌肌纤维数目由孵化后6个增加至315个,总面积从13.18μm2增加到7 839.58μm2,孵化后13日龄的增生生长占优势,其他发育阶段,肥大生长一直占主导优势。