双歧杆菌代谢母乳寡糖机制的研究进展

母乳寡糖(human milk oligosaccharides,HMO)结构复杂,其能够选择性地促进母乳喂养婴儿肠道中益生菌双歧杆菌的生长。婴儿肠道相关双歧杆菌具有糖苷酶等分子工具,使其能够代谢HMO,且代谢过程具有菌株特异性。本文总结了HMO的结构特点,探讨了婴儿肠道相关双歧杆菌代谢HMO的机制,重点分析了双歧杆菌代谢HMO的种内差异以及代谢过程涉及到的分子工具的研究进展。     

Testing a chemical series inspired by plant stress oxylipin signalling agents for herbicide safening activity

BACKGROUND

Herbicide safening in cereals is linked to a rapid xenobiotic response (XR), involving the induction of glutathione transferases (GSTs). The XR is also invoked by oxidized fatty acids (oxylipins) released during plant stress, suggesting a link between these signalling agents and safening. To examine this relationship, a series of compounds modelled on the oxylipins 12‐oxophytodienoic acid and phytoprostane 1, varying in lipophilicity and electrophilicity, were synthesized. Compounds were then tested for their ability to invoke the XR in Arabidopsis and protect rice seedlings exposed to the herbicide pretilachlor, as compared with the safener fenclorim.

RESULTS

Of the 21 compounds tested, three invoked the rapid GST induction associated with fenclorim. All compounds possessed two electrophilic carbon centres and a lipophilic group characteristic of both oxylipins and fenclorim. Minor effects observed in protecting rice seedlings from herbicide damage positively correlated with the XR, but did not provide functional safening.

CONCLUSION

The design of safeners based on the characteristics of oxylipins proved successful in deriving compounds that invoke a rapid XR in Arabidopsis but not in providing classical safening in a cereal. The results further support a link between safener and oxylipin signalling, but also highlight species‐dependent differences in the responses to these compounds. © 2018 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

生物体砷代谢解毒机制的研究进展

近年来砷污染问题引起了世界各地的广泛关注,砷通过地下水饮用、食物链传递进入人体,对人体产生伤害。因此,必须采取措施控制砷进入动植物和人体的数量,改变砷在生物体内的赋存形态,从而降低砷对人体产生的毒害。本文综述了砷在生物体内的基本代谢过程;砷代谢过程中的关键酶：砷酸盐还原酶、亚砷酸甲基转移酶的结构及功能。通过调控砷代谢过程中的关键酶活性,可改变砷在生物体内的形态配比和毒性,从而降低砷对人体产生的健康风险。     

气调胁迫下3种中药材储藏期害虫谷胱甘肽转移酶活性研究

研究了药材甲(Stegobium paniceum)、烟草甲(Lasioderma serricorne)和咖啡豆象(Araecerus fasciculatus)3种中药材储藏期害虫谷胱甘肽转移酶的酶活性,探讨了该酶在CO2气调胁迫下的应激反应。结果表明,药材甲、烟草甲和咖啡豆象的谷胱甘肽转移酶比活力分别为(0.339 2±0.015 5)、(0.966 0±0.259 3)nmol/(min•mg)和(0.370 2±0.032 8)nmol/(min•mg)。CO2气调对3种昆虫GSTs的影响研究结果表明,在CO2气调处理3、6、9 h时,药材甲、烟草甲和咖啡豆象成虫的GSTs酶比活力均有一定程度的升高。可见,CO2气调亚致死处理对3种实验昆虫GSTs有一定的诱导激活作用。研究结果对于储藏物害虫气调杀虫机制的分析有指导意义。     

Synthesis and Bioactivity of Ancorinoside B,a Marine Diglycosyl Tetramic Acid

The sponge metabolite ancorinoside B was prepared for the first time in 16 steps and 4% yield. It features a β-d-galactopyranosyl-(1→4)-β-d-glucuronic acid tethered to a d-aspartic acid-derived tetramic acid. Key steps were the synthesis of a fully protected d-lactose derived thioglycoside, its attachment to a C₂₀-aldehyde spacer, functionalization of the latter with a terminal N-(β-ketoacyl)-d-aspartate, and a basic Dieckmann cyclization to close the pyrrolidin-2,4-dione ring with concomitant global deprotection. Ancorinoside B exhibited multiple biological effects of medicinal interest. It inhibited the secretion of the cancer metastasis-relevant matrix metalloproteinases MMP-2 and MMP-9, and also the growth of Staphylococcus aureus biofilms by ca 87% when applied at concentrations as low as 0.5 µg/mL. This concentration is far below its MIC of ca 67 µg/mL and thus unlikely to induce bacterial resistance. It also led to a 67% dispersion of preformed S. aureus biofilms when applied at a concentration of ca 2 µg/mL. Ancorinoside B might thus be an interesting candidate for the control of the general hospital, catheter, or joint protheses infections.     

Modulation of key metabolic enzyme of <Emphasis Type="Italic">Labeo rohita</Emphasis> (Hamilton) juvenile: effect of dietary starch type,protein level and exogenous α-amylase in the diet

A 60-day feeding trial was conducted to delineate the effect of both gelatinized (G) and non-gelatinized (NG) corn with or without supplementation of exogenous α-amylase, either at optimum (35%) or sub-optimum (27%) protein levels, on blood glucose, and the key metabolic enzymes of glycolysis (hexokinase, HK), gluconeogenesis (glucose-6 phosphatase, G6Pase and fructose-1,6 bisphosphatase, FBPase), lipogenesis (glucose-6 phaosphate dehydrogenase, G6PD) and amino acid metabolism (alanine amino transfersae, ALT and aspartate amino transferase, AST) in Labeo rohita. Three hundred and sixty juveniles (average weight 10 ± 0.15 g) were randomly distributed into 12 treatment groups with each of two replicates. Twelve semi-purified diets containing either 35 or 27% crude protein were prepared by including G or NG corn as carbohydrate source with different levels of microbial α-amylase (0, 50, 100 and 150 mg kg⁻¹). The G corn fed groups showed significantly higher (P < 0.05) blood glucose and G6PD activity, whereas G6Pase, FBPase, ALT and AST activity in liver was higher in the NG corn fed group. Dietary corn type, α-amylase level in diet or their interaction had no significant effect (P > 0.05) on liver HK activity, but the optimum crude protein (35%) fed group showed higher HK activity than their low protein counterparts. The sub-optimum crude protein (27%) fed group showed significantly higher (P < 0.05) G6PD activity than the optimum protein fed group, whereas the reverse trend was observed for HK, G6Pase, FBPase, ALT and AST activity. Addition of 50 mg α-amylase kg⁻¹ feed showed increased blood glucose and G6PD activity of the NG corn fed group, whereas the reverse trend was found for G6Pase, FBPase, ALT and AST activity in liver, which was similar to that of the G or NG corn supplemented with 100/150 mg α-amylase kg⁻¹ feed. Data on enzyme activities suggest that NG corn in the diet significantly induced more gluconeogenic and amino acid metabolic enzyme activity, whereas G corn induced increased lipogenic enzyme activity. Increased amino acid catabolic enzyme (ALT and AST) activity was observed either at optimum protein (35%) irrespective of corn type or NG corn without supplementation of α-amylase irrespective of protein level in the diet.     

瑞香狼毒提取物对山楂叶螨的生物活性及酶活性影响

瑞香狼毒的氯仿、石油醚、甲醇提取物对果树重要害螨山楂叶螨有很好的内吸和触杀活性；对氯仿提取物处理后的成螨体内几种重要酶系活性测定发现，在内吸处理中，其对蛋白酶、谷胱甘肽－S－转移酶，酯酶同功酶有不同程度的激活作用；在触杀处理中，对蛋白酶、谷胱甘肽－S－转移酶影响不明显，对酯酶同功酶有一定的抑制作用；研究表明，瑞香狼毒可以有效杀死山楂叶螨，是一种很有利用价值的杀虫植物。     

日本血吸虫冻融童虫苗和提纯抗原苗对水牛的免疫保护试验

应用日本血吸虫两种抗原疫苗免疫水牛的减虫率、肝组织虫卵的减少率和攻击前及解剖前的平均增重分别为：日本血吸虫冻融苗（Ｆ／Ｔ苗）组为６４．８％ 、８１．８％ 和２８．５ｋｇ、５５．３ｋｇ;日本血吸虫提纯抗原苗天然谷胱甘肽Ｓ－转移酶（ｎＧＳＴ 苗）组为３３．１９％ 、７９．７％ 和３７．８ｋｇ、６３．７ｋｇ