Production of Avaroferrin and Putrebactin by Heterologous Expression of a Deep-Sea Metagenomic DNA

The siderophore avaroferrin (1), an inhibitor of Vibrio swarming that was recently identified in Shewanella algae B516, was produced by heterologous expression of the biosynthetic gene cluster cloned from a deep-sea sediment metagenomic DNA, together with two analogues, bisucaberin (2) and putrebactin (3). Avaroferrin (1) is a macrocyclic heterodimer of N-hydroxy-N-succinyl cadaverine (4) and N-hydroxy-N-succinyl-putrescine (5), whereas analogues 2 and 3 are homodimers of 4 and 5, respectively. Heterologous expression of two other related genes from culturable marine bacteria resulted in production of compounds 1–3, but in quite different proportions compared with production through expression of the metagenomic DNA.     

人参皂苷生物合成及调控功能基因研究进展(1)

三萜类化合物是重要的药用活性成分,其生物合成相关功能基因研究是调控这些化学成分生物合成和积累的重要理论依据。人参是重要的经济植物,具有很高的药用价值。开展人参功能基因研究有利于进一步探究人参生长发育、代谢调控的生理生化过程。本文总结了近年来人参皂苷生物合成相关功能基因的研究成果,并对三萜类化合物生物合成相关功能基因的研究方法进行了总结,对人参皂苷生物合成相关功能基因研究方法进行了展望。     

The use of ethylene diffusers is comparable to treatments with sprayed ethylene to reduce the damage caused by the olive moth (<Emphasis Type="Italic">Prays oleae</Emphasis> Bern.)

In 2002 and 2003, six field experiments were conducted at three olive groves of southern Spain in order to compare the effects of two types of ethylene treatments (sprayed and diffusers) on the olive losses caused by the olive moth (Prays oleae Bern.) as well as on the activity and effectiveness of oofagous predators. Both treatments showed to be effective to control the pest; in the two years studied the mean reduction in final infestation due to ethylene was of 35% with respect to the controls trees, and none affected negatively the action of natural predators of P. oleae. In addition, the use of diffusers set on the trees at the end of flowering period will help the farmers to overcome the problems of determination of optimum time for sprayed treatments of ethylene.     

Research Progress on Effects of Proline on Reproductive Performance of Sows

Proline is a cyclic α-imino acids,meanwhile it also can be considered as a functional amino acid for mammals and plays an important role in protein synthesis,organism metabolism,wound healing,anti-oxidant and immune reactions. The studys have found that extra dietary supplementation of moderated proline has great significance in improving the growth and development of conceptus,piglets, embryo,mammary gland and placenta of sows,at the same time it also can prevent intrauterine growth restriction. The author reviewed structure characters and physicochemical properties,anabolism and catabolism of proline,and especially focused on its effects on the reproductive performance of pregnancy sows and potential regulation mechanism aiming to provide some help for the researchers in the field of sows.     

Lipid biosynthesis from [14C]-glucose in the coral Montipora digitata

ABSTRACT:     Glucose has been implicated in functioning as a form of carbon translocated from symbiont zooxanthellae to the host coral cell. The present paper describes the lipid biosynthesis from [¹⁴C]-glucose in the coral tissue. To study the incorporation of [¹⁴C]-glucose into lipids, the branch tips of the coral Montipora digitata were incubated with [¹⁴C]-glucose or another radiolabeled substrates. The lipid biosynthesis from [¹⁴C]-glucose was dependent on light, and was decreased by dark conditions or by photosystem II inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Of the lipid classes, the light dependency was more pronounced with the biosynthesis of triacylglycerols (TG) and wax compared with phospholipids. Examination of [¹⁴C]-label distribution in the glycerolipids suggested that [¹⁴C]-glucose supplied mainly the fatty acid moiety of newly synthesized TG, while [¹⁴C]-glucose provided evenly the fatty acid moiety and the glycerol skeleton of phospholipids. The comparison of [¹⁴C]-labeling of lipid from host coral tissue and symbiont zooxanthellae suggested that [¹⁴C]-glucose entered the coral cell and was processed in parallel in the zooxanthellae and host cells. Furthermore, the coral cells used various [¹⁴C]-labeled sugars for lipid synthesis with similar lipid labeling profile as was the case for glucose. The current study thus supports the view that the low-molecular-weight compound, sugars and amino acids, once translocated from zooxanthellae to host cell were metabolized toward lipogenesis as well as glycerol.     

大豆吡哆醇生物合成蛋白基因(PDX)的电子克隆和进化分析

电子克隆(In silicocloning)是随着基因组计划和EST计划实施而发展起来的利用生物信息学手段进行基因克隆的新方法。根据物种间同源基因相对保守的特点,以拟南芥(Arabidopsis thaliana)吡哆醇生物合成蛋白cDNA序列为信息探针,对大豆(Glycine max)EST数据库进行同源搜索和序列拼接,获得了1 280 bp长的大豆吡哆醇生物合成蛋白的基因序列(GenBank登陆号为DQ139265)。经过RT-PCR扩增、基因组PCR扩增、分子克隆和序列分析验证,结果表明与电子克隆序列完全一致。该基因具有完整的开放阅读框架(ORF,20~955 bp),编码311个氨基酸。通过与水稻、日本百脉根、烟草、截形苜蓿等物种的吡哆醇生物合成蛋白序列比对,发现该基因具有高度的保守性。表明根据物种间同源基因序列,对跨物种间EST数据库进行同源检索、筛选、拼接,是克隆基因的有效途径。     

Alkaloid accumulation in capsules of the selfed and cross-pollinated poppy

In harmony with international regulations the creation of poppy cultivars with high alkaloid content as well as free of alkaloids is in progress. In the course of selection procedures, five poppy cultivars of high chemical diversity, ‘Kheops’, ‘AT, ‘Tebona’, ‘Kék Gemona’ and ‘Przemko’, were selfed and crossed in two successive years (2000‐01). After full ripening, both the biomass production and the alkaloid content of capsules of selfed and crossed plants were determined. When the castrated alkaloid‐free cultivar ‘Przemko’ (accumulating only 0.01 mg/100 g morphine in capsules) was pollinated with cultivars rich in alkaloids, the morphine content of its capsules increased to 0.9‐7.5 mg/100 g‐values. Based on the well‐known biosynthetic background of poppy alkaloids, this can be explained by promotion of (S)‐norcoclaurine synthesis, which seems to be suppressed in alkaloid‐free plants; but tissues of the developing hybrid seeds, which contain a combined gene pool of both alkaloid‐free cultivar and that of the pollen donor plants, release this suppression. The chemical metaxenia also manifested itself in other combinations. In particular, the appearance of narcotine (0.1‐1.1 mg/100 g) in the narcotine‐free cultivars ‘Kheops’, ‘A1’ and ‘Przemko’ can be explained biochemically. If the narcotine‐type plants ‘Kék Gemona’ (accumulating 11.3 mg/g narcotine) were used for pollination, the developing seed tissue, which contains the gene pool of narcotine biosynthesis, might contribute to the suppression of the activity of 1,2‐dehydroreticuline reductase, which leads to the accumulation of narcotine at the cost of morphinanes.     

水稻淀粉合成代谢相关基因与千粒重QTLs的连锁分析

稻米淀粉的合成和积累是水稻千粒重形成的重要基础之一。在水稻千粒重QTLs定位分析基础上，对本研究克隆的14个水稻胚乳淀粉合成与积累相关基因及已报道的和预测的42个相关基因进行了电子定位分析，比较水稻淀粉合成代谢相关基因与千粒重QTLs的连锁关系。发现有38个基因位点与千粒重QTLs连锁，说明千粒重形成与胚乳淀粉积累与淀粉结构形成代谢密切相关。本研究结果将为进一步研究水稻产量形成的分子机理提供参考。     

Inheritance of flower colour and flavonoid pigments in Gerbera

The flower colour of Gerbera, an important ornamental cut flower, is derived from carotenoids and flavonoids. The knowledge of enzymological and genetic control of flavonoid biosynthesis is still incomplete. The present paper summarizes the results obtained at our institute between 1981 and 1993. The material for the investigation of phenotypic segregation and segregation of flavonoids after chromatographic analysis came from 408 progenies of controlled crosses. Phenotypic segregation analysis showed acyanic genotypes to be homozygous recessive and recessive epistatic over cyanic genotypes, respectively. This was confirmed by the existence of two loci controlling steps in biosynthesis (fht, dfr or ans) showing recessive mutants and complementary gene action after crosses. Flavone formation is effected by one dominant allele (fns⁺); dominant and recessive genotypes are now available. Regarding anthocyanidin inheritance, an unusual epistasis of 4′-hydroxylation (pelargonidin formation) over 3′,4′-hydroxylation (cyanidin formation) was observed. Final proof of the postulated gene actions will come from enzymological and molecular biological investigations of the chemogenetically defined Gerbera genotypes now available.