Four climate cycles of recurring deep and surface water destabilizations on the Iberian margin     

Martrat B  Grimalt JO  Shackleton NJ  de Abreu L  Hutterli MA  Stocker TF 《Science (New York, N.Y.)》2007,317(5837):502-507

Centennial climate variability over the last ice age exhibits clear bipolar behavior. High-resolution analyses of marine sediment cores from the Iberian margin trace a number of associated changes simultaneously. Proxies of sea surface temperature and water mass distribution, as well as relative biomarker content, demonstrate that this typical north-south coupling was pervasive for the cold phases of climate during the past 420,000 years. Cold episodes after relatively warm and largely ice-free periods occurred when the predominance of deep water formation changed from northern to southern sources. These results reinforce the connection between rapid climate changes at Mediterranean latitudes and century-to-millennial variability in northern and southern polar regions.  相似文献   

Ecology. A positive feedback with negative consequences     

Lerdau M 《Science (New York, N.Y.)》2007,316(5822):212-213

  相似文献   

Cross-linking cellular prion protein triggers neuronal apoptosis in vivo     

Solforosi L  Criado JR  McGavern DB  Wirz S  Sánchez-Alavez M  Sugama S  DeGiorgio LA  Volpe BT  Wiseman E  Abalos G  Masliah E  Gilden D  Oldstone MB  Conti B  Williamson RA 《Science (New York, N.Y.)》2004,303(5663):1514-1516

Neuronal death is a prominent, but poorly understood, pathological hallmark of prion disease. Notably, in the absence of the cellular prion protein (PrPC), the disease-associated isoform, PrPSc, appears not to be intrinsically neurotoxic, suggesting that PrPC itself may participate directly in the prion neurodegenerative cascade. Here, cross-linking PrPC in vivo with specific monoclonal antibodies was found to trigger rapid and extensive apoptosis in hippocampal and cerebellar neurons. These findings suggest that PrPC functions in the control of neuronal survival and provides a model to explore whether cross-linking of PrPC by oligomeric PrPSc can promote neuronal loss during prion infection.  相似文献   

Molecular characterization of chestnut plants selected for putative resistance to Phytophthora cinnamomi using SSR markers     

María Victoria González  Beatriz Cuenca  Marián López  María Jesús Prado  Manuel Rey 《Scientia Horticulturae》2011

A set of nine short sequence repeat (SSR) loci was used for the molecular characterization of 32 accessions of 15 chestnut trees selected in the field because of their putative resistance to the ink disease caused by Phytophthora spp. The goal of the present study was to determine the genetic identity of those selected European chestnut trees (Castanea sativa) or interspecific hybrids, considering that hybridization programs between European chestnut and Asiatic species (mainly Japanese chestnut, Castanea crenata) have been carried out in Galicia (Spain) since the early 20th century. The results showed that the analyzed SSR loci were useful to discriminate three Asiatic and the European species of Castanea. The joint information provided by a factorial correspondence analysis (FCA) and the presence of privative alleles allowed the putative molecular assignment of the selected plants to a certain identity. Most of them were determined as hybrids between C. crenata and C. sativa. The individuals coded C036 and C048 were assigned, with a high probability, to C. sativa due to their clustering with accessions of this species and because they had a number of privative alleles of this species. Only a few individuals could not be assigned to any particular genotype.  相似文献   

Classification of pumpkin seed oils according to their species and genetic variety by attenuated total reflection Fourier-transform infrared spectroscopy     

Saucedo-Hernández Y  Lerma-García MJ  Herrero-Martínez JM  Ramis-Ramos G  Jorge-Rodríguez E  Simí-Alfonso EF 《Journal of agricultural and food chemistry》2011,59(8):4125-4129

Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), followed by multivariate treatment of the spectral data, was used to classify seed oils of the genus Cucurbita (pumpkins) according to their species as C. maxima, C. pepo, and C. moschata. Also, C. moschata seed oils were classified according to their genetic variety as RG, Inivit C-88, and Inivit C-2000. Up to 23 wavelength regions were selected on the spectra, each region corresponding to a peak or shoulder. The normalized absorbance peak areas within these regions were used as predictors. Using linear discriminant analysis (LDA), an excellent resolution among all categories concerning both Cucurbita species and C. moschata varieties was achieved. The proposed method was straightforward and quick and can be easily implemented. Quality control of pumpkin seed oils is important because Cucurbita species and genetic variety are both related to the pharmaceutical properties of the oils.  相似文献   

Fermented vegetables containing benzoic and ascorbic acids as additives: benzene formation during storage and impact of additives on quality parameters     

Casado FJ  Sánchez AH  De Castro A  Rejano L  Beato VM  Montaño A 《Journal of agricultural and food chemistry》2011,59(6):2403-2409

Chemical and sensorial changes related to the use of benzoates and ascorbic acid as additives in packed fermented vegetables were investigated. For this, three selected vegetables (green olives, cucumbers, and caperberries) stored under different conditions (glass or plastic containers, ambient or refrigerated storage) were used. In all cases, benzoic acid remained unchanged (glass bottle) or decreased slightly (plastic pouch) at prolonged storage. Ascorbic acid was partially or totally degraded during storage, the degradation rate depending on the storage conditions and the vegetable matrix. Benzene levels higher than 10 μg/L were found in cucumbers and caperberries containing both additives, but only when packed in plastic pouches and after prolonged storage at room temperature. In these conditions, an appreciable browning of brine, related to AA degradation, was also found. The use of benzoate alone had a significant influence on vegetable color, but flavor was not significantly affected at the benzoate levels tested. On the basis of the present study, benzoates should be removed from fermented vegetable formulations containing ascorbic acid to eliminate possible benzene formation during long-term storage.  相似文献   

Analytical and sensorial characterization of the aroma of wines produced with sour rotten grapes using GC-O and GC-MS: identification of key aroma compounds     

Barata A  Campo E  Malfeito-Ferreira M  Loureiro V  Cacho J  Ferreira V 《Journal of agricultural and food chemistry》2011,59(6):2543-2553

In the present work, the aroma profiles of wines elaborated from sound and sour rot-infected grapes as raw material have been studied by sensory analysis, gas chromatography-olfactometry (GC-O), and gas chromatography-mass spectrometry (GC-MS), with the aim of determining the odor volatiles most likely associated with this disease. The effect of sour rot was tested in monovarietal wines produced with the Portuguese red grape variety Trincadeira and in blends of Cabernet Sauvignon and sour rotten Trincadeira grapes. Wines produced from damaged berries exhibited clear honey-like notes not evoked by healthy samples. Ethyl phenylacetate (EPhA) and phenylacetic acid (PAA), both exhibiting sweet honey-like aromas, emerged as key aroma compounds of sour rotten wines. Their levels were 1 order of magnitude above those found in controls and reached 304 and 1668 μg L(-1) of EPhA and PAA, respectively, well above the corresponding odor thresholds. Levels of γ-nonalactone also increased by a factor 3 in sour rot samples. Results also suggest that sour rot exerts a great effect on the secondary metabolism of yeast, decreasing the levels of volatiles related to fatty acids and amino acid synthesis. The highest levels of γ-decalactone of up to 405 μg L(-1) were also found in all of the samples, suggesting that this could be a relevant aroma compound in Trincadeira wine aroma.  相似文献   

Competencies: a cure for pre-med curriculum     

Anderson WA  Amasino RM  Ares M  Banerjee U  Bartel B  Corces VG  Drennan CL  Elgin SC  Epstein IR  Fanning E  Guillette LJ  Handelsman J  Hatfull GF  Hoy RR  Kelley D  Leinwand LA  Losick R  Lu Y  Lynn DG  Neuhauser C  O'Dowd DK  Olivera T  Pevzner P  Richards-Kortum RR  Rine J  Sah RL  Strobel SA  Walker GC  Walt DR  Warner IM  Wessler S  Willard HF  Zare RN 《Science (New York, N.Y.)》2011,334(6057):760-761

  相似文献   

Tracheostomy tube occlusion during emergency tracheostomy in a pigmy goat     

Santos LC  Gleed RD  Campoy L  Martin-Flores M  Ludders JW 《Veterinary anaesthesia and analgesia》2011,38(6):624-625

  相似文献   

Hydroxytyrosol 4-beta-D-glucoside,an important phenolic compound in olive fruits and derived products     

Romero C  Brenes M  García P  Garrido A 《Journal of agricultural and food chemistry》2002,50(13):3835-3839

There is increasing interest in olive polyphenols because of their biological properties as well as their contribution to the color, taste, and shelf life of olive products. However, some of these compounds remain unidentified. It has been shown that hydroxytyrosol 4-beta-D-glucoside (4-beta-D-glucosyl-3-hydroxyphenylethanol) coeluted with hydroxytyrosol [(3,4-dihydroxyphenyl)ethanol] under reversed phase conditions in the phenolic chromatograms of olive pulp, vegetation water, and pomace of olive oil processing. A method to separate this compound from hydroxytyrosol by HPLC has been developed. The concentration of this glucoside increased in olive pulp with maturation and could be the main phenolic compound in mature olives. In contrast, the presence of this compound was not detected in olive oil by using HPLC-MS. The compound must be considered both in table olives and olive oil processing because of its glucose and hydroxytyrosol contribution to these products.  相似文献