Haemato-immunological and stress responses of Labeo rohita (Hamilton) fingerlings: effect of rearing temperature and dietary gelatinized carbohydrate

A feeding trial of 70‐days was carried out to study the haemato‐immunological and stress responses of Labeo rohita fingerlings reared at two water temperatures [ambient (Amb) – 27 °C and 32 °C] fed with graded levels of gelatinized corn carbohydrate (GC). Two hundred and sixteen fingerlings were randomly distributed into six treatment groups in triplicate. Three semi‐purified diets were prepared containing 30% crude protein with graded levels of GC 40%, 50% and 58%. The six treatment groups were T₁ (40% GC × Amb), T₂ (40% GC × 32 °C), T₃ (50% GC × Amb), T₄ (50% GC × 32 °C), T₅ (58% GC × Amb) and T₆ (58% GC × 32 °C). The blood glucose level was significantly (p < 0.05) lowered in groups fed with 58% GC level. Neither dietary GC levels nor temperature had a significant (p > 0.05) effect on serum cortisol and superoxide dismutase activity. Lysozyme activity was significantly higher (p < 0.05) in T₁ during pre‐ and post‐challenge period while temperature alone had a significant (p < 0.05) effect on post‐challenge Nitroblue Tetrazolium and found higher at 32 °C. A significant effect of GC levels and rearing temperature was recorded on WBC in the pre‐ and post‐challenge period. Highest pre‐challenge WBC was observed in T₄ group and in the post‐challenge period T₁ group recorded maximum. Water temperature had significant effect on pre‐challenge haemoglobin content, highest being at 32 °C (T₂). A significant (p < 0.05) effect of rearing temperature and dietary GC level on total serum protein and albumin was also observed. Highest total serum protein and albumin was recorded in T₁ and globulin in T₂. Percentage survival after challenging with Aeromonas hydrophila was highest in T₁ followed by T₃ group and lowest in T₆. The results obtained in the present study suggest that L. rohita fingerlings may utilize higher levels of dietary GC at higher temperature (32 °C) but may affect its immunity status.     

金针菇JA/SA信号通路基因鉴定及其对外源JA/SA应答

本研究鉴定了金针菇茉莉酸(JA)信号通路的4个关键基因:COI1、PDF1.2、MYC2-1、MYC2-2与水杨酸(SA)信号通路的4个关键基因:PR1-1、PR1-2、NPR1-1、NPR1-2。NBT染色法和荧光定量结果表明,金针菇JA/SA信号通路可应答外源JA/SA,50μmol·L~(-1)外源JA和500μmol·L~(-1)外源SA处理金针菇菌丝12h可显著提高JA/SA信号通路基因的转录水平,基因PDF1.2响应JA诱导最明显,可作为JA信号通路标记基因;JA/SA信号转导途径间存在协同或拮抗作用:SA信号转导通路中NPR1蛋白对JA信号转导通路中PDF1.2基因表达有抑制作用,外源JA/SA的相对浓度决定其作用的强弱。     

Effects of a new inhibitor K-23 on electron transport in photosystem II of higher plants

The effects of inhibitor K-23 on variable fluorescence, oxygen evolution and DCIP photoreduction were investigated. K-23 promotes the oxygen evolution and DCIP photoreduction at low concentration and inhibits them at relatively high concentrations, while an efficient inhibition at low concentration is found in variable fluorescence. These data further confirm that the inhibitor K-23 action is based on its redox interaction rather than quenching effect. Addition of DPC could not restore the DCIP photoreduction activity. It is suggested that the inhibitory site is at the acceptor side. Using ferricyanide as electron acceptor, the effect of K-23 and DCMU on the oxygen evolution of trypsin-treated thylakoids was investigated. It is found that oxygen evolution of trypsin-treated thylakoids was insensitive to DCMU, whereas became more sensitive to K-23 and also the promotion of K-23 at low concentration disappeared. This strongly indicates that trypsin treatment modified the binding site of K-23 and increased its accessibility to K-23 target site. From the comparison of K-23 with DCMU, we conclude that the binding site of K-23 is different from that of DCMU even though they both bind at the acceptor side.     

九孔鲍血细胞吞噬能力的研究

在体外研究九孔鲍(Haliotis diversicolor supertexta)血细胞的吞噬能力,初步了解九孔鲍血细胞的吞噬功能。结果表明,在室温20~22℃下,不同反应时间(30、60、90min)对血细胞吞噬作用的影响不显著;不同吞噬物比例(酵母聚糖与血细胞数量之比为2、5、10)对血细胞吞噬作用有显著影响,吞噬率和吞噬指数随着吞噬物比例的增大而上升。测定不同温度(10、20、30℃)下血细胞对酵母聚糖的吞噬作用,20℃时血细胞的吞噬率、吞噬指数最高;10℃与30℃时的吞噬率、吞噬指数均较低,但与20℃的相比没有显著差异。电镜观察证实酵母聚糖颗粒位于血细胞的吞噬体内。在室温20~22℃、反应时间60min的条件下,测定血细胞对金黄色葡萄球菌(10个菌/每个血细胞)的吞噬作用(吞噬率为23.7%、吞噬指数为0.51)。在硝基四氮唑蓝(NBT)还原试验中,血细胞在酵母聚糖的刺激下,发生呼吸暴发产生了超氧阴离子。     

绿豆幼苗发育初期Pchlide光还原的研究

为了探讨被子植物幼苗发育初期Pchlide还原机制,本文采用不同波长的光照和抗生素处理,分析了光照诱导绿豆黄花幼苗发育初期Pchlide和Chlide的变化以及抗生素对Pchlide和Chlide的变化的影响。结果表明:绿豆黄化幼苗在光照最初0.5 h,单色光有利于Pchlide的还原和新Pchlide的生物合成;光照2 h后,单色光不利于Chlide的酯化;CH明显抑制绿豆幼苗子叶Chlide的酯化速度,说明Chlide的酯化是受细胞核基因控制。