Isolation of 4-methylthio-3-butenyl glucosinolate from Raphanus sativus sprouts (kaiware daikon) and its redox properties

The most promising among glucosinolates (GLs) are those bearing in their aglycon an extra sulfur function, such as glucoraphasatin (4-methylthio-3-butenyl GL; GRH) and glucoraphenin (4-methylsulfinyl-3-butenyl GL; GRE). The GRE/GRH redox couple is typically met among secondary metabolites of Raphanus sativus L. and, whereas GRE prevails in seeds, GRH is the major GL in full-grown roots. During the 10 days of sprouting of R. sativus seeds, the GRE and GRH contents were determined according to the Eurpean Union official method (ISO 9167-1). In comparison to the seeds, the GRE content in sprouts decreased from about 90 to about 12 micromol g(-1) of dry weight (dw), whereas a 25-fold increase--from about 3 to 76 micromol g(-1) of dw--of the GRH content was measured. An efficient pure GRH gram-scale production process from R. sativus (kaiware daikon) sprouts resulted in significant yield improvement of up to 2.2% (dw basis). The reaction of GRH with both H2O2 and ABTS*+ radical cation was investigated. Whereas H2O2 oxidation of GRH readily resulted in complete transformation into GRE, ABTS*+ caused complete decay of the GL. Even though not directly related to its radical scavenging activity, the assessed reducing capacity of GRH suggests that R. sativus sprouts might possess potential for health benefits.     

Wild rabbit restocking for predator conservation in Spain

The decline of rabbit (Oryctolagus cuniculus) populations in Mediterranean Spain has been shown to be one of the main threats to rabbit-specialist predators such as the Iberian lynx (Lynx pardina) and the Spanish imperial eagle (Aquila adalberti), two species which are in serious danger of extinction. Consequently, corrective measures such as increasing rabbit populations by restocking have been carried out to help the recovery of predator populations. In order to determine the general applicability of rabbit restocking for predator conservation, we performed three experimental restockings and evaluated their success in relation to season, habitat quality and the number of animals introduced. Rabbits were released either in large or small numbers in all four seasons of the year, and in habitat types defined as `poor' or `rich' according to the food availability for rabbits. For each restocking we evaluated rabbit survival, degree of residency and expected population increase. As a rule, the highest restocking success occurred whenever smaller number of rabbits were released in the richest quality habitat. Restocking during the breeding season was less successful than in other seasons. Problems concerning intraspecific competition, reproductive failure and diseases are discussed.     

Phospholipid interactions protect the milk allergen alpha-lactalbumin from proteolysis during in vitro digestion

Interactions with food components may alter the resistance of food proteins to digestion, a property thought to play an important role in determining allergenic properties. The kinetics of breakdown of the bovine milk allergen alpha-lactalbumin during in vitro gastrointestinal digestion was found to be altered by interactions with physiologically relevant levels of phosphatidylcholine (PC), a surfactant that is abundant both in milk and is actively secreted by the stomach. Breakdown during gastric digestion was slowed in the presence of PC and accompanied by small alterations in the profile of resulting peptides, with little effect being observed during subsequent duodenal digestion. alpha-Lactalbumin was found to unfold at gastric (acid) pH, giving a CD spectrum similar to that obtained for the partially folded state it is known to adopt at pH values below its isoelectric point. Fluorescence polarization studies performed at low pH indicated that this partially unfolded form of the protein was able to penetrate into the PC vesicles. These interactions are probably responsible for the slowing of gastric digestion by reducing the accessibility of the protein to pepsin. These findings show that interactions with other food components, such as lipids, may alter the rate of breakdown of food proteins in the gastrointestinal tract. It underlines the importance of the food matrix in affecting patterns of food allergen digestion and hence presentation to the immune system and that in vitro digestion systems used for assessing digestibility of allergens must take account of surfactants.     

Occurrence and distribution of organochlorine pesticides (OCPs) in tomato (Lycopersicon esculentum) crops from organic production

Organochlorine pesticides (OCPs) were quantified by GC-ECD in tomato (Lycopersicon esculentum) during a vegetation period. Plants were harvested at 15, 60, and 151 days after seed germination. Leaves, stem, roots, and fruit (peel and flesh) were analyzed separately. The results showed that tomato plants were able to accumulate OCPs from soils, and a trend to reach the equilibrium among tissues at mature stages was also observed. Endosulfans comprised the main OCP group, probably due to its spray during summer months in the surrounding areas. Banned pesticides such as DDTs, heptachlor, and dieldrin were found. OCPs levels in the fruit were below the maximum residues limits (MRL) considered by the Codex Alimentarius. DDE/DDT and alpha-/gamma-HCH ratios of <1 would indicate recent inputs of DDT and lindane in the environment. The occurrence of OCPs in the study farm, where agrochemicals have never been used, is a result of atmospheric deposition of those pesticides.     

Chlorogenic acids as a potential criterion in coffee genotype selections

A systematic study by HPLC was conducted to determine the content of chlorogenic acids in green coffee beans of the Variedad Colombia (Coffea arabica Caturra var. x Híbrido de Timor) and in other genotypes of interest of C. arabica, Coffea canephora, Híbrido de Timor, and the F1 offspring derived from the crossing Caturra x Híbrido de Timor. Comparisons were made of the total content of these acids, their quantitative differences, and the presence or absence of some of them, using parametric statistical techniques and multivariate analysis. Total content differences were found between C. canephora accessions, between Típica and Caturra varieties of C. arabica, and between Híbrido de Timor accessions. The chromatographic profile comparisons with principal component analysis separated in the first component C. canephora accessions from the rest of the genotypes, whereas the second component separated C. canephora accessions.     

上海乡土树种及其在城市绿化建设中的应用

随着生态城市被列为上海市的建设发展目标,城市绿化建设被赋予了新的目标和内涵,生态林将逐渐成为城市绿化的主体,作为生态林建设基础的乡土树种也将得到更为广泛的应用.通过实地调查和资料调查,统计分析了上海市的乡土树种,共42科89属128种(含变种),可以分为常绿阔叶乔木、常绿阔叶灌木、半常绿阔叶灌木、落叶阔叶乔木、落叶阔叶小乔木和落叶阔叶灌木等6个类型.分析了乡土树种在上海绿化建设中的意义和应用现状,并对其应用进行了展望.表1参21     

披针叶黄华生物碱成分研究

采用 GC- MS联用分析技术从披针叶黄华总生物碱中分离鉴定出 12个喹喏里西啶生物碱 ,即无叶豆碱 ,N-甲基金雀花碱 ,金雀花碱 ,白羽扇豆碱 ,黄华碱 ,臭豆碱 ,N-甲醛基金雀花碱 ,Dodecahydro- 7,14 -methanodipyrido[1,2 - a:1′,2′- E][1.5 ]diazocine,Pyridine1- acetyl- 1,2 ,3,4 - tetrahydro- 5 - (2 - piperdinyl) ,7,14 -Methano- 2 H,6 H- dipyrido[1,2 - a:1′,2′- e][1,5 ]diaz,1,1- Dim ethyl- 3- (2 - nitrophenyl) ,7,14 - Methano- 4 H,6 H-dipyrido[1,2 - a:1′,2′- e][1,5 ]diaz。后 5种化合物为首次从该植物中鉴定     

Outgassing behavior and composition of comet C/1999 S4 (LINEAR) during its disruption

The gas activity of comet C/1999 S4 (LINEAR) was monitored at radio wavelengths during its disruption. A runaway fragmentation of the nucleus may have begun around 18 July 2000 and proceeded until 23 July. The mass in small icy debris (相似文献   

Method for estimation of ocean current velocity from satellite images

Barotropic instability waves on a shear interface propagate at the average speed of the water on the two sides. Assuming the instability to be excited by tidal oscillations, the phase speed is the wavelength divided by the tidal period. If the water is at rest on one side of the shear layer the current speed on the other side can be calculated. This method, applied to the Gulf Stream beyond Cape Hatteras as seen in satellite images, gives estimates of current speed in general agreement with in situ observations.     

Light-enhanced free radical formation and trypanocidal action of gentian violet (crystal violet)

Transmission of Chagas' disease by transfusion of blood containing Trypanosoma cruzi has often been reported, and gentian violet, a triarylmethane dye, is widely used by blood banks in attempts to eliminate such transmission. In a study of intact trypanosomes, gentian violet was found to undergo a one-electron reduction to produce a carbon-centered free radical as demonstrated by electron spin resonance spectroscopy. Either reduced nicotinamide adenine dinucleotide or the reduced dinucleotide phosphate could serve as a source of reducing equivalents for the production of this free radical by homogenates of Trypanosoma cruzi. The formation of this free radical, and the trypanocidal action of gentian violet, were enhanced by light. The enhanced free radical formation may be the basic cause of the selective toxicity of gentian violet to Trypanosoma cruzi.