细菌表达 dsRNA 介导桔小实蝇 flightin基因的 RNA 干扰

【目的】探索饲喂细菌表达目标基因dsRNA介导桔小实蝇flightin基因RNAi的可行性。【方法】将桔小实蝇flightin基因的相应干扰片段构建至L4440干扰载体,并转化大肠杆菌HT115(DE3)菌株,利用IPTG诱导表达flightin基因对应的dsRNA,命名为flightin-dsRNA。【结果】通过饲喂表达flightin-dsRNA的大肠杆菌10倍浓缩菌液,桔小实蝇flightin基因的表达普遍出现了不同程度的上调,其中,雌虫饲喂后5、10、20 d,雄虫饲喂后5 d与对照差异显著,雄虫饲喂后15 d诱发约43%的下调;该方法对桔小实蝇飞行能力及胸部肌肉发育未产生明显影响。【结论】通过饲喂表达flightin-dsRNA的大肠杆菌对桔小实蝇flightin基因进行RNA干扰不可行或干扰效果不明显。     

日本血吸虫体内5-HT的定量合成与降解

用反相离子对色谱和同位素示踪技术研究了日本血吸虫体内５－ＨＴ的定量、合成与降解。结果表明：日本血吸虫体内５－ＨＴ的含量为２．９２±０．２９μｇ／ｇ。雌、雄虫分别为２．５７±０．３５和３．３２±０．１９μｇ／ｇ。用３Ｈ－Ｔｒｙ培养虫体，由ＨＰＬＣ分离收集，经液闪测定，有３Ｈ－５－ＨＴＰ、３Ｈ－５－ＨＴ、３Ｈ－ＨＩＡＡ生成；分别用３Ｈ－５－ＨＴＰ和３Ｈ－５－ＨＴ培养虫体，则有３Ｈ－５－ＨＴ、３Ｈ－５－ＨＩＡＡ和３Ｈ－５－ＨＩＡＡ生成。异丙异烟肼能增加虫体内５－ＨＴ的含量和降低５－ＨＩＡＡ的水平，而对氯苯丙氨酸，反苯环丙胺，赛庚啶等对虫体５－ＨＴ含量均无影响。以上结果显示：日本血吸虫体内存在５－ＨＴ的内源性合成与降解途径，其过程相似于哺乳动物，但参与的酶却存在异同性     

用于RNA干扰研究的大肠杆菌表达系统的条件优化

选取在E.coli中对于dsRNA表达比较重要的3个因素,即诱导时间、诱导温度和诱导剂IPTG浓度。利用已经构建好的大肠杆菌E.coli HT115(DE3),并结合正交试验设计研究dsRNA在HT115(DE3)内的最优表达条件。结果表明,工程菌在诱导时间8 h、诱导温度30℃、诱导剂浓度10.0 mmol/L的培养条件下所得到的dsRNA表达量最大。     

冀东稻区基于低温复合菌系HT20的秸秆腐解因素研究

为探索低温启动型且具有纤维素强分解能力的复合菌系HT20作用下秸秆腐解的影响因素。采用室内培养试验,通过响应曲面优化法Box-Behnken设计建立HT20添加量、温度、秸秆含水率和尿素添加量与秸秆腐解率之间的模型,结合大田微区模拟试验验证HT20实际田间应用效果,并与常用的4种秸秆腐熟剂进行比较。结果表明:秸秆腐解率受HT20添加量、温度、秸秆含水率的影响显著,且各影响因素间交互作用对秸秆腐解率影响显著,尿素添加量与HT20添加量之间交互作用对秸秆腐解率影响不显著。与不添加腐熟剂(CK)和常用腐熟剂相比,HT20腐解速率提高20.10%～81.46%,腐解时间缩短17.62～183.41d,养分提高5.44%～71.49%,微生物数量增加1.57%～76.14%。表明,低温复合菌HT20在冀东滨海稻区还田秸秆腐解中起到了主导作用。研究结果为本地秸秆还田中低温复合菌系HT20的施用提供理论指导,为我国北方稻区秸秆还田提供技术支撑。     

Serotonin stimulates ovarian maturation and spawning in the black tiger shrimp Penaeus monodon

Serotonin (5-hydroxytryptamine, 5HT) has been reported to induce ovarian maturation and spawning in the crayfish Procambarus clarkii and white Pacific shrimp Litopenaeus vannamei. The aim of this study was to explore the role of exogenous 5HT on the reproductive performance of the black tiger shrimp Penaeus monodon. 5HT solution was injected into domesticated P. monodon broodstock at 50 μg/g body weight and ovarian maturation and spawning were recorded. The presence of 5HT in the ovary and oviduct of P. monodon was also studied by immunohistochemistry and its levels in the ovary by enzyme link immunoabsorbance assay (ELISA). The 5HT-injected P. monodon developed ovarian maturation and spawning rate at the level comparable to that of unilateral eyestalk-ablated shrimp. Hatching rate and the amount of nauplii produced per spawner were also significantly higher in the 5HT-injected shrimp, compared to the eyestalk-ablated shrimp. 5HT-positive reactions were found in the follicular cells of pre-vitellogenic oocytes, in the cytoplasm of early vitellogenic oocytes and on the cell membrane and cytoplasm of late vitellogenic oocytes. 5HT in the ovary was present at 3.53 ± 0.26 ng/mg protein level in previtellogenic stage and increased to 17.03 ± 0.57 ng/mg protein level in the mature stage of the ovary. The results suggest a significant role of 5HT, possibly directly on the ovary and oviduct, on the reproductive function of female P. monodon.     

Effects of quinoa hull meal on piglet performance and intestinal epithelial physiology

Saponin-containing feed additives have shown positive effects on pig performance. Quinoa hull has high saponin content and may be of interest as a feed additive. This study aimed to evaluate quinoa hull meal (QHM) as a feed additive in a pig diet. The effects of QHM were assessed for three dosages of South American (SA) origin (100, 300 and 500 mg/kg) and one dosage of Danish (DK) quinoa (300 mg/kg). In addition, the effect of dietary SA-QHM and SA-QHM-extract on jejunal epithelial physiology was studied ex vivo in Ussing chambers. The experiment included 400 piglets weaned at 28 ± 2 days of age and the experimental period was 4 weeks. Piglets were weighed initially and finally and feed intake registered. The ex vivo studies were performed with epithelium from 40 pigs receiving control or SA-QHM. Epithelium from each pig was placed into eight Ussing chambers, where four concentrations of SA-QHM-extract were added. Epithelial permeability, Na(+)-dependent glucose transport and serotonin (5-HT) and theophylline-induced secretion were measured. The results showed that QHM had no influence on piglet's growth (p = 0.41) or feed intake (p = 0.17). In spite of a large difference in saponin content between SA-QHM and DK-QHM (28.7% and 2.0% w/w respectively) the source did not affect pig performance. The ex vivo studies revealed no effect (p > 0.05) of adding QHM-extract into the medium. The permeability and glucose induced absorption were highest (p = 0.003 and p = 0.04 respectively) in epithelium from pigs that consumed 100 or 300 mg/kg SA-QHM. The secretory response to 5-HT was not affected (p = 0.59) by dietary treatments, but the theophylline-induced secretion decreased (p = 0.02) with increasing dietary SA-QHM. The changes in epithelial physiology measured ex vivo did not affect animal performance in vivo in this study.     

Hypophagic and dipsogenic effect of the 5‐HT1A receptor agonist 8‐OH‐DPAT in broiler chickens

The effects of the 5‐HT_1A receptor agonist 8‐OH‐DPAT on food and water intake in male broiler chickens were investigated. The injection of 25 or 50 μg/kg of 8‐OH‐DPAT 15 min before refeeding in fasted animals produced a decrease in food intake. No effect was observed in drinking. The injection of 25 or 50 μg/kg of the 8‐OH‐DPAT 60 min after the start of refeeding did not produce any significant modification in food intake. No effect on drinking was recorded. The agonist 8‐OH‐DPAT injected 15 min before water presentation in water‐deprived chickens, produced an increased drinking 60 min after the presentation of water. No effect on food intake was observed. The results show that the effect on food intake of the agonist 8‐OH‐DPAT in fasted–refed broiler chickens was similar to those observed in mammals and layer‐strain chickens. However, the agonist did not alter significantly the food intake when the broilers were fed 60 min before the injection. These results are contrary to the observed effects in mammals and in layer‐strain chickens. Probably, the selection for rapid growth rate in broilers causes modifications in the feeding control pattern. The comparison between broilers and layers strain may be a useful tool to elucidate the complex mechanisms involved in food and water intake regulation in chickens.     

BHBA对HT22细胞中ACE表达的影响

生酮饮食(KD)已被证实具有神经保护作用,但其机制尚不明确。本试验以小鼠海马神经元HT22为细胞模型,利用2 mmol/Lβ-羟基丁酸酯(BHBA)对HT22细胞进行处理,通过荧光定量PCR,免疫蛋白印迹和信号通路阻断试验,观察BHBA对HT22细胞ACE表达的影响,并探讨参与调控的信号通路。结果表明,2 mmol/L BHBA可通过激活HT22细胞内GPR109A受体和ERK1/2信号通路进而增加HT22细胞中ACE的表达。     

Apoptotic Activity of New Oxisterigmatocystin Derivatives from the Marine-Derived Fungus Aspergillus nomius NC06

Sponge-derived fungi have recently attracted attention as an important source of interesting bioactive compounds. Aspergillus nomius NC06 was isolated from the marine sponge Neopetrosia chaliniformis. This fungus was cultured on rice medium and yielded four compounds including three new oxisterigmatocystins, namely, J, K, and L (1, 2, and 3), and one known compound, aspergillicin A (4). Structures of the compounds were elucidated by 1D and 2D NMR spectroscopy and by high-resolution mass spectrometry. The isolated compounds were tested for cytotoxic activity against HT 29 colon cancer cells, where compounds 1, 2, and 4 exhibited IC₅₀ values of 6.28, 15.14, and 1.63 µM, respectively. Under the fluorescence microscope by using a double staining method, HT 29 cells were observed to be viable, apoptotic, and necrotic after treatment with the cytotoxic compounds 1, 2, and 4. The result shows that compounds 1 and 2 were able to induce apoptosis and cell death in HT 29 cells.