山苍子油主成分及其衍生物对植物病原菌的抑制作用

为筛选出新的对油茶炭疽病菌(Colletotrichum gloeosporioides)、西瓜枯萎病菌(Fusarium oxysporum f.sp.Niveum)和水稻稻瘟病菌(Pyricularia grisea)3种常见植物病原菌有效的杀菌剂,采用菌丝生长速率法,研究了山苍子油主成分及其衍生物15种化合物对这3种常见植物病原菌的抑制效果。结果表明:15种化合物对3种植物病原菌的生长均表现出一定的抑制作用,而且随着质量浓度的升高,抑制作用增强。通过本试验从15种化合物中依次筛选出对油茶炭疽病菌、水稻稻瘟病菌和西瓜枯萎病菌的抑菌作用最强的分别为乙位紫罗兰酮、柠檬腈、鸢尾酮,其EC50依次为31.53,37.64,133.60 mg/L。油茶炭疽病菌、水稻稻瘟病菌经乙位紫罗兰酮、柠檬腈处理后,其菌体细胞相对渗透率明显增大,表明细胞膜发生了破坏;而西瓜枯萎病菌经鸢尾酮处理后细胞相对渗透率先增大后减少,表明细胞膜没有发生破坏。     

2-辛亚砜-5,8-二甲氧基-1,4萘醌通过ROS/Akt通路诱导HepG2细胞凋亡

为研究修饰后的萘醌类衍生物对人肝癌细胞株HepG2诱导细胞凋亡作用及其机制。采用MTT、流式和Western blot方法观察2-辛亚砜-5,8-二甲氧基-1,4萘醌对人肝癌细胞的生长作用。结果表明:2-辛亚砜-5,8-二甲氧基-1,4萘醌可通过促进早期ROS水平升高,抑制Akt的磷酸化水平,并选择性地激活p38,ERK信号通路,从而抑制肝癌细胞株HepG2细胞的增殖并诱导其发生凋亡。     

天然柠檬醛衍生物对食品腐败细菌的抑制活性

采用抑菌圈法和琼脂二倍稀释法,测试了12种天然柠檬醛衍生化合物对大肠埃希菌、金黄色葡萄球菌、表皮葡萄球菌、绿脓杆菌的抑菌活性。结果表明,12种天然柠檬醛衍生化合物对4种细菌均有一定的抑菌效果。其中,异丁酸香叶酯对大肠埃希菌抑菌效果最佳,抑菌圈直径为14.83 mm,最低抑菌浓度为8 mg·L^-1;橙花醇对金黄色葡萄球菌及表皮葡萄球菌抑制效果最佳,抑菌圈直径分别为15.80和14.33 mm,最低抑菌浓度分别为8和16 mg·L^-1;香叶醇对绿脓杆菌抑制效果最佳,抑菌圈直径为15.00 mm,最低抑菌浓度为16 mg·L^-1。经天然柠檬醛衍生物处理后,食品腐败细菌细胞膜的相对渗透率升高,表明这些化合物可能对细菌细胞膜具有破坏作用。     

Design,synthesis and acaricidal activity of novel strobilurin derivatives containing pyrimidine moieties

BACKGROUND: The intermediate derivatisation method based on bioisosteric replacement led to the discovery of the lead strobilurin compound 5a. To produce new strobilurin analogues with improved activity, a series of substituted pyrimidines were synthesised and bioassayed. RESULTS: The compounds were identified by ¹H NMR, IR, MS and elemental analysis. The highly active compound 5g was studied by X‐ray diffraction. Preliminary bioassays demonstrated that some of the title compounds exhibited excellent acaricidal activity against Tetranychus cinnabarinus (Boisd.) at 10 mg L^?1. The relationship between structure and acaricidal activity is reported. CONCLUSION: The present work demonstrates that strobilurin derivatives containing pyrimidine moieties can be used as possible lead compounds for developing novel acaricides. Copyright © 2010 Society of Chemical Industry     

肉牛日粮补饲铜对瘤胃VFA浓度和尿中嘌呤衍生物排出量的影响

选3头装有永久性瘤胃瘘管的西门塔尔杂交肉牛,采用3×3拉丁方设计,研究日粮补饲无机铜(0、8和18mg/kgDM)对瘤胃VFA浓度和尿嘌呤衍生物排出量的影响。结果表明:日粮补饲铜对瘤胃VFA浓度和摩尔比例有明显影响(P<0.05),与对照组相比,18mg/kgDM的补饲明显提高乙酸的摩尔比,降低丙酸、丁酸的浓度(P<0.05),而日粮中铜的补饲对尿中嘌呤衍生物排出量没有显著影响(P>0.05),每千克日粮补饲18mg/kgDM无机铜可明显促进瘤胃的发酵。     

不同营养水平对4～6月龄荷斯坦犊牛尿中嘌呤衍生物排出量的影响

本试验采用3头(120±5)日龄、体重为(72±2)kg的荷斯坦公犊牛,通过调整日粮营养水平来观察其尿中嘌呤衍生物(PD)的排出规律,比较其与成年反刍动物之间的差异,考察犊牛期能否用尿嘌呤衍生物法来估测瘤胃微生物蛋白。试验设计3种营养水平日粮,采用随机区组试验设计。结果发现,犊牛尿中嘌呤衍生物中尿酸大约为50%～75%,而在成年反刍动物尿酸不到15%。PD的排出量随可消化有机物(DOM)和可消化粗蛋白(DCP)进食量升高而上升,存在弱的相关性(R2=0.76,n=9)。其排出水平为0.12～0.24mmol/(BW0.75·d)。作为估测成年反刍动物微生物蛋白合成量的另一个指标[PD]×BW0.75/[C](其中[PD]为嘌呤衍生物浓度,[C]为尿中肌酐酸浓度,BW0.75为代谢体重,简称PDC),与DOM和DCP进食量存在负相关,这与成年反刍动物的研究结果是相反的。     

新型2-酰基氰基乙酸类衍生物SYP-10898的研究

以对叔丁基氯苄为起始原料,经氰化、酯化、酯交换和酰基化4步反应合成了新化合物2-酰基氰基乙酸酯类衍生物 SYP-10898 ,其化学结构经核磁共振氢谱和元素分析确证。室内生物活性测试结果表明, SYP-10898 对朱砂叶螨Tetranychus cinnabarinus成螨的LC50值为3.67 mg/L,优于对照药剂丁氟螨酯(cyflumetofen)。田间试验结果表明,在50 mg/L剂量下, SYP-10898 对柑桔红蜘蛛Panonychus citri表现了良好的速效性和持效性,3 d后的防效在93%以上,30 d后的防效在79%以上。     

Enhancement of fungicidal and insecticidal activity by reductive alkylation of chitosan

A series of N-alkyl chitosan (NAC) derivatives were synthesized using a reductive alkylation reaction to examine their fungicidal and insecticidal activity. The chemical structures were characterized by IR and (1)H NMR spectroscopy, and the degree of substitution (DS) ranged from 0.02 to 0.37. Their fungicidal activity was evaluated against the grey mould Botrytis cinerea Pers ex Fr (Leotiales: Sclerotiniaceae) and the rice leaf blast pathogen Pyricularia grisea Sacc [Teleomorph: Magnaporthe grisea (Hebert) Barr] by a radial growth bioassay. It was of interest that most of the NAC derivatives were more active against both fungi than chitosan itself. The most active derivative was N-(2,2-diphenylethyl)chitosan with EC50 values of 0.031 and 0.23 g L(-1) against B. cinerea and P. grisea respectively. In addition, some derivatives, at higher concentrations up to 1.0 g L(-1), inhibited the mycelial growth and spore formation of P. grisea. Bioassays against larvae of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) with the NAC derivatives at a rate of 5.0 g kg(-1) in artificial diet demonstrated that N-(3-phenylbutyl)chitosan was the most active compound. In addition, N-propylchitosan, N-undecanylchitosan and N-(3-phenylpropyl)chitosan derivatives strongly inhibited larval weight gain in S. littoralis, with respective reductions of 76, 66 and 65% after 4 days of feeding on treated diet.     

Effect of dietary energy on digestibilities,rumen fermentation,urinary purine derivatives and serum metabolites in Tibetan and small‐tailed Han sheep

Tibetan sheep are indigenous to the Qinghai–Tibetan Plateau, graze the grassland all year round without supplementation and are well‐adapted to the harsh conditions. Small‐tailed Han sheep were introduced to the plateau and are raised mainly in feedlots. Based on their different backgrounds, we hypothesized that the ability to cope with poor diets would be better in Tibetan than in Han sheep. To test our prediction, we examined the effect of dietary energy on apparent digestibilities, rumen fermentation, urinary purine derivatives and serum metabolites by using a 4 × 4 Latin square design in each sheep breed. Four diets were formulated to be low in crude protein (~7%) but to differ in metabolizable energy concentration. Average daily gain was greater in Tibetan than in Han sheep (p < 0.01) and increased linearly with an increase in energy intake (p < 0.001). The digestibilities of dry matter, organic matter, gross energy, and neutral and acid detergent fibres were greater in Tibetan than in Han sheep (p < 0.05). Ruminal pH was lower (p < 0.05), while volatile fatty acids (VFAs), urea‐N, ammonia‐N and soluble protein‐N concentrations were higher (p < 0.05) in Tibetan than in Han sheep. As a molar proportion of total VFA, acetate decreased (p < 0.001) with an increase in dietary energy whereas propionate and butyrate increased (p < 0.05). Urinary purine derivative excretion was greater in Tibetan than in Han sheep (p < 0.01), as was microbial nitrogen production; both parameters increased with dietary energy (p < 0.01). Serum concentrations of glucose, insulin and insulin‐like growth factor‐1 increased (p < 0.05) as energy level increased, while non‐esterified fatty acids and growth hormone decreased (p < 0.05). It was concluded that Tibetan sheep were better able to cope with low‐protein, low‐energy diets and, consequently, our prediction was supported.     

Effect of treating alfalfa silage with pistachio by‐products extract on Saanen dairy goats performance and microbial nitrogen synthesis

A lactation experiment was conducted to determine the influence of addition of pistachio by‐products extract (PBE) to alfalfa silage (AS) on performance, rumen fermentation, milk yield and composition, and microbial nitrogen synthesis. Eight multiparous dairy goats (1.8 ± 0.25 kg of milk yield) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments to compare two types of AS (supplemented with or without PBE) with two levels of dietary crude protein (14% vs. 16% CP). Dietary treatments were (i) AS with 14% CP of DM diet without PBE (14%CP?PBE), (ii) AS with 14% CP of DM diet with PBE (14%CP + PBE), (iii) AS with 16% CP of DM diet without PBE (16%CP?PBE) and (iv) AS with 16% CP of DM diet with PBE (16%CP + PBE). PBE was sprayed on fresh alfalfa at a ratio of 500 ml/kg alfalfa DM to get the final concentration of 1% tannin as tannic acid equivalent on DM basis. Intake of CP was greater (p < 0.01) in goats fed 16% CP diets than those fed 14% CP diets, regardless of PBE supplementation. Supplementation of PBE tended to decrease (p = 0.09) rumen NH₃‐N concentration regardless of the level of CP in the diet. Supplementation of PBE tended (p = 0.09) to decrease total purine derivatives regardless of the level of CP in the diet with no significant change in microbial nitrogen supply. Efficiency of microbial nitrogen synthesis (EMNS) had a tendency (p = 0.07) to decrease in PBE supplemented diets. There was also a tendency (p = 0.10) for more EMNS in 14% CP fed goats than those fed 16% CP diets. Therefore, AS supplemented with PBE may lead to less concentration of ruminal NH₃‐N because of decreased degradation of CP by rumen micro‐organisms in response to pistachio by‐products tannins.