蜡蚧轮枝菌Km9803代谢产物对果蝇和菜青虫的杀虫活性

测定了分别经过固体培养和液体培养后再分别经石油醚、乙酸乙酯、丙酮和甲醇溶液提取的8种蜡蚧轮枝菌Km9803提取物对果蝇和菜青虫的杀虫活性,结果以液体培养菌体的甲醇提取物对果蝇的胃毒作用最好,在5%浓度下24h对雄果蝇毒杀率达100.0%,对雌果蝇毒杀率达66.7%;固体培养菌体的乙酸乙酯提取物对菜青虫的作用效果最明显,24h菜青虫死亡率达100.0%.表明蜡蚧轮枝菌代谢产物对果蝇和菜青虫有较好的杀虫活性.     

Manufacturing molecules through metabolic engineering

Metabolic engineering has the potential to produce from simple, readily available, inexpensive starting materials a large number of chemicals that are currently derived from nonrenewable resources or limited natural resources. Microbial production of natural products has been achieved by transferring product-specific enzymes or entire metabolic pathways from rare or genetically intractable organisms to those that can be readily engineered, and production of unnatural specialty chemicals, bulk chemicals, and fuels has been enabled by combining enzymes or pathways from different hosts into a single microorganism and by engineering enzymes to have new function. Whereas existing production routes use well-known, safe, industrial microorganisms, future production schemes may include designer cells that are tailor-made for the desired chemical and production process. In any future, metabolic engineering will soon rival and potentially eclipse synthetic organic chemistry.     

Oncogenic purine derivatives: evidence for a possible proximate oncogen

Two additional urinary metabolites of the chemical oncogen 3-hydroxyxanthine are now identified as 8-chloroxanthine and 8-methylmercaptoxanthine. Such products are thought to be derived from a reactive intermediate which can be tentatively considered to be a proximate oncogen. Since each of these 8-substituted xanthines has also been obtained in vitro by reactions of 3-acetoxyxanthine with chloride ion or methionine, their production in vivo can be explained as resulting through the metabolic formation of an activated ester with a reactivity similar to that of the chemical model.     

瘿螨寄主植物抗性研究进展

从植物组成抗性与诱导抗性两个方面,回顾了植物抗瘿螨的研究进展。其中,组成抗性研究已较为透彻,本文从遗传、组织结构与形态、代谢产物3个方面进行综述;而诱导抗性从诱导抗性方式论述,主要有瘿螨取食、化学物质诱导和机械损伤3个方面。诱导抗性还有待进一步的深入研究,仍有很大的研究空间。     

喜树碱生物合成途径及其相关酶研究现状及展望

喜树碱是从喜树Camptotheca acuminata中发现的单萜类吲哚生物碱,已经成为继紫杉醇之后广泛使用的植物性抗癌药,具有非常广阔的市场前景。研究喜树碱的生物合成途径,对于了解喜树碱的合成机制,提高次生代谢工程喜树碱的产量,解决目前资源紧缺造成的供求矛盾等问题均具有重要的意义。在查阅、综合文献的基础上,将喜树碱生物合成途径以异胡豆苷为分界线,分为上游途径和下游途径;并对各种中间产物合成、关键酶和关键基因等作了详细的阐述。在此基础上,提出了调控喜树碱合成的可能方法,并提出了喜树碱合成研究未来的研究重点。图3表1参29     

基于品牌价值理论的河北省农产品品牌对接京津战略分析

随着京津冀一体化速度的加快,京津冀农业协作发展的趋势增强,河北省农产品品牌对接京津已经受到广泛关注,河北省农产品品牌对接京津战略也提上了日程。运用品牌价值理论的动态性分析,基于互动的三角模型对河北省农产品品牌战略进行分析,发现河北省农产品品牌存在自身品牌弱、发展滞后、市场竞争激烈、需求不大、品牌不能得到市场认可等问题,最后提出相应的对策建议。     

IN VITRO ACTIVITY OF EXTRACTS OF FIVE MEDICINAL PLANT SPECIES ON PLANT PATHOGENIC FUNGI

• Ethyl acetate and 95% ethanol extracts from T. chinensis rhizomes gave great inhibition on six plant pathogenic fungi • T. chinensis has potential to be a new natural fungicide resource • T. chinensis has potential to be used for the preservation of agricultural and forestry products such as fruits and vegetables The antifungal effectiveness of extracts of five medicinal plant species was determined. The inhibitory activity of extracts of Eucalyptus tereticornis, Xanthium sibiricum, Artemisia argyi, Tupistra chinensis and Pyrola calliantha were evaluated against the mycelial growth of the plant pathogenic fungi Aspergillus niger, Botrytis cinerea, Penicillium digitatum, P. expansum, P. italicum and Rhizopus stolonifer. All plant extracts were prepared at 60°C using solvents (either water, 50% ethanol (v/v), 95% ethanol (v/v), ethyl acetate or petroleum ether). Fungicidal effects of all plants tested were confirmed. Different extracts from the same plant species gave different degrees of inhibition. All aqueous extracts had weak or no activity on all fungi tested. Ethyl acetate and 95% ethanol extracts from T. chinensis rhizomes gave greater inhibition and a broader spectrum inhibition than the other extracts. T. chinensis may have potential as a new natural fungicide and may be used for the preservation of agricultural and forestry products such as fruits and vegetables.     

Dopa and dopamine in glusulase: possible artifact in studies on catecholamine metabolism

Relatively high concentrations of dopa and dopamnine were found in Glusulase, an enzyme preparation widely used in studies on catecholamine metabolism. This contamination may be a source of error in some studies, particularly in those measuring the endogenous concentrations of these catechols and their metabolic products.     

传统酵子中产香酵母菌的分离?鉴定及发酵香气的检测

[目的]从酵子中筛选出发酵香气较好的菌种,使其发酵产物能增强发酵面制品风味。[方法]通过平板划线分离法,从传统酵子中分离出1株酵母样真菌,对其形态学特征及18S r DNA区序列进行分析,采用气相色谱-质谱(GC-MS)法对该菌株糊化小麦淀粉发酵产生的挥发性香气成分进行检测。[结果]被命名为FN001的该菌株属于Wickerhamomy cesanomalus,该酵母菌发酵产生的香气组分主要为酯类、醇类和酸类,包括乙醇、乙酸乙酯、丁醇、丁酸乙酯、乙酸丁酯、丁酸丁酯、苯乙醇、丁酸、乙酸等,其中,乙醇的相对百分含量高达20.33%、乙酸乙酯14.52%、丁醇14.51%、乙酸丁酯13.90%。[结论]利用此菌株发酵可为发酵面制品提供较浓郁的香气来源。     

Formation of "photodieldrin" by microorganisms

Photodieldrin, previously reported as the major conversion product of dieldrin by sunlight, was found among the metabolic products of dieldrin among microorganisms isolated from various environments including soil, water (Lake Michigan), rat intestines, and rumen stomach contents of a cow.     

Structure of the receptor for insulin-like growth factor II: the puzzle amplified

The insulin-like growth factor II (IGF-II) is a polypeptide hormone with structural homologies to insulin and insulin-like growth factor I (IGF-I). In contrast to these other hormones, the in vivo function of IGF-II is not known. Although IGF-II can stimulate a broad range of biological responses in isolated cells, these responses have usually been found to be mediated by the insulin and IGF-I receptors. Recently, the receptor for IGF-II was found to also be the receptor for mannose-6-phosphate. Since this latter receptor has been implicated in targeting of lysosomal enzymes, the question is now raised of whether the same protein can also mediate metabolic responses to IGF-II.     

Energy scaling in marsupials and eutherians

Marsupials have been shown to have basal metabolic rates below those of eutherian mammals. Now metabolic rates below thermoneutrality are found to be equivalent in both taxa. Two models are proposed to explain the observed metabolic patterns: in one, marsupials differ only in having reduced basal metabolic rates; in the other, the reduced marsupial basal metabolic rates combined with a reduced body temperature and elevated conductance. The metabolic costs of existence below thermoneutrality appear to be similar for both taxa. The difference in basal metabolic rate may be of energetic significance or merely a phylogenetic coincidence.     

沙柳木蠹蛾性信息素的化学合成

沙柳木蠹蛾是荒漠区灌木林的主要钻蛀性害虫之一,可利用性信息素对其进行生物防治。对沙柳木蠹蛾的性信息素主成分顺-7-十四碳烯-1-醇乙酸酯(Z7-14:OAC)和顺-5-十四碳烯-1-醇乙酸酯(Z5-14:OAC)进行了立体选择性合成,其中,Z7-14:OAC采用炔化物反应引入炔基,经过顺式或反式还原得到相应的不饱和醇类化合物,再酯化为所需的乙酸酯;Z5-14:OAC的合成是将四氢吡喃直接开环制得溴代戊醇乙酸酯,再通过Wittig反应与正壬醛偶联成不饱和酯类化合物。产物经红外光谱仪(IR)和气质联用(GC-MS)确认,可用于该虫的诱杀、交配干扰和虫情测报。     

45种食用菌液体发酵产物的抗氧化活性

对45种食用菌发酵液、菌丝水提液和醇提液的还原力、清除羟自由基(.OH)和超氧阴离子自由基(O2.-)的能力进行测定.结果表明:大部分菌种的发酵产物均具有一定的还原力及清除.OH和O2.-的能力;菌丝醇提液的抗氧化活性比菌丝水提液强.利用模糊综合评价法比较45种食用菌发酵液、菌丝醇提液和水提液的抗氧化活性.结果表明,桦褐孔菌发酵液、赤芝菌丝醇提液、榆耳菌丝水提液的抗氧化活性最高,可以作为潜在的抗氧化剂或保健品开发利用.     

基于UPLC-MS/MS方法的家禽水产品中氯霉素残留检测

为家禽水产品中的氯霉素残留快速检测提供参考,以氯霉素-D5为内标,用乙酸乙酯提取样品氯霉素残留、正己烷进行脱脂净化、UPLC-MS/MS方法进行氯霉素残留含量检测。结果表明:在氯霉素浓度为0.2~10ng/mL时,基质标准曲线的方程为Y=0.816 397 X-0.038 239,R2=0.998 2,氯霉素与峰面积的线性关系良好,最低检出浓度为0.1μg/kg,样品的添加回收率为80%~110%,RSD5%。该方法可用于家禽及水产品中氯霉素残留定性和定量检测,且其精密度和准确度良好,操作简单快速。     

次生代谢产物的生物分子特性决定基因适合度

种群内与生物代谢相关基因的突变,必然会导致新酶、新代谢产物的形成,从而使生物体具有化学物质的多样性。新物质对生物体及细胞的生存或有利,或不利。该研究从选择进化的角度论述了代谢相关基因发生突变所产酶产物的生物分子活性是决定该基因能否保存的必要条件。同时指出,鉴于产物的生物分子性质可分为3个基本类型,而且选择压力对每种类型的选择存在差异性,从而使生物体具有化学多样性,并进一步形成代谢的多样性。     

Effects of thyroxin on amino acid incorporation into protein

The effect of thyroxin on the in vitro incorporation of dl-leucine-l-C(14) into the protein of rat liver homogenates has been investigated. Both thyroxin pretreatment in vivo and thyroxin in vitro at a concentration of 1 x 10(-5) M were found to increase the rate of amino acid incorporation. The increased activity following the thyroxin pretreatment in vivo was found to be localized in the mitochondrial fraction. It is suggested that the acceleration of metabolic rate characteristic of thyroxin action may be secondary to the stimulation of energy-requiring reactions such as protein synthesis.     

生物农药印楝素的热稳定性研究

研究了水分、黄曲霉、溶剂、乳化剂、稳定剂等因素对印楝素热稳定性的影响 ,结果表明 :除去水分、黄曲霉后的固体印楝素稳定性有明显改善 ,印楝素在各种溶剂中的稳定性为 :二甲苯 -乙腈 ( 2∶1 )≈二甲苯 -乙酸乙酯 ( 2∶1 ) >二甲亚砜 >乙腈 >乙酸乙酯 >丙酮 >甲醇≈乙醇 ;各种乳化剂的存在加速印楝素的分解 ,其中热分解速度 :十二烷基苯磺酸钠 >吐温 - 80 >CH1 0 0 >吐温 - 2 0≈CH40 0 ;加入热稳定剂后能明显改善印楝素的稳定效果 ,其中环氧化豆油的稳定效果较好     

黄芪多糖和枯草芽孢杆菌代谢产物在PK-15细胞上对TGEV的影响

为了研究黄芪多糖和枯草芽孢杆菌代谢产物在PK-15细胞上对猪传染性胃肠炎病毒(TGEV)的影响,在TGEV感染PK-15细胞时分别加入枯草芽孢杆菌代谢产物、黄芪多糖以及联合物,采用MTT法检测其病毒抑制率,荧光定量PCR法检测枯草芽孢杆菌代谢产物及黄芪多糖联合后对TGEV N及IFN-γmRNA表达量的影响。结果表明:枯草芽孢杆菌代谢产物具有抗TGEV作用,单独使用黄芪多糖同样能抑制TGEV感染PK-15细胞,联合处理后病毒抑制率显著上升。荧光定量PCR结果表明,经过联合物处理的PK-15细胞中的TGEV N基因表达量显著降低,3 h和6 h时PK-15细胞内的IFN-γmRNA表达量显著上升。     

高效液相色谱串联质谱法快速测定水产品中硝基呋喃类代谢物研究

建立了一种液相色谱串联质谱方法快速检测水产品中呋喃唑酮代谢物3-氨基-2-唑烷基酮(AOZ)、呋喃它酮代谢物5-甲基吗啉-3-氨基-2-唑烷基酮(AMOZ)、呋喃西林代谢物氨基脲(SEM)、呋喃妥因代谢物1-氨基-乙丙酰脲(AHD)等硝基呋喃类代谢物。样品在40℃水浴超声下经盐酸水解、邻硝基苯甲醛快速衍生化、乙酸乙酯提取、浓缩净化后,采用HPLC-ESI-MS/MS检测分析,在多反应监测模式(MRM)下,外标法定量。以乙腈-0.05%甲酸水为流动相,采用梯度洗脱,30 min内可将4种硝基呋喃代谢物分离。在0.25～25μg/kg范围内标准曲线的相关系数大于0.998。在不同添加水平下的回收率为81.9%～111.6%,定量限(LOQ)为1μg/kg,检出限(LOD)为0.25μg/kg。该方法准确、灵敏,达到了检测水产品中的硝基呋喃类代谢物的要求。