Ellagitannins,flavonoids, and other phenolics in red raspberries and their contribution to antioxidant capacity and vasorelaxation properties     

Mullen W  McGinn J  Lean ME  MacLean MR  Gardner P  Duthie GG  Yokota T  Crozier A 《Journal of agricultural and food chemistry》2002,50(18):5191-5196

Analysis of extracts of Glen Ample raspberries (Rubus idaeus L.) by gradient, reverse phase HPLC with diode array and tandem mass spectrometry identified eleven anthocyanins, including cyanidin-3-sophoroside, cyanidin-3-(2(G)-glucosylrutinoside), cyanidin-3-glucoside, cyanidin-3-rutinoside, pelargonidin-3-sophoroside, pelargonidin-3-(2(G)-glucosylrutinoside), and pelargonidin-3-glucoside. Significant quantities of an ellagitannin, sanguiin H-6, with an M(r) of 1870 were detected along with lower levels of a second ellagitannin, lambertianin C, which has an M(r) of 2804. Other phenolic compounds that were detected included trace levels of ellagic acid and its sugar conjugates along with one kaempferol- and four quercetin-based flavonol conjugates. Fractionation by preparative HPLC revealed that sanguiin H-6 was a major contributor to the antioxidant capacity of raspberries together with vitamin C and the anthocyanins. Vasodilation activity was restricted to fractions containing lambertianin C and sanguiin H-6.  相似文献   

Element mass balances for South Carolina Coastal Plain watersheds     

Leonard Robert Gardner 《Water, air, and soil pollution》1981,15(3):271-284

Element mass balance estimates for South Carolina Coastal Plain watersheds indicate that fertilizers and liming materials are the major sources for inputs of Ca, Mg, K, Cl, and HCO₃ whereas precipitation is the major input for Na and SO₄. Stream flow is the chief mode of output for all of these elements. A balance between input and output is evident only for Cl. Retentions of 50% or more are shown by Ca, Mg, K, HCO₃ and SO₄ whereas Na shows an apparent net loss. The retention of Ca, Mg and HCO₃ suggests that less than 25% of the dolomitic liming materials applied to the landscape actually dissolve and that the carbonate chemistry of Lower Coastal Plain streams is therefore probably largely controlled by seepage of groundwaters from underlying calcareous aquifers. The retention of K and the loss of Na may be due to cation exchange reactions on soil clays whereas the apparent retention of SO₄ is probably due to reduction to H₂S in floodplain environments and soil adsorption.  相似文献   

Purification and identification of linoleic acid hydroperoxides generated by soybean seed lipoxygenases 2 and 3     

Fukushige H  Wang C  Simpson TD  Gardner HW  Hildebrand DF 《Journal of agricultural and food chemistry》2005,53(14):5691-5694

It has been known that lipoxygenase (LOX) isozymes exhibit differences in product formation, but most product information to date is for LOX 1 among soybean (Glycine max) LOX isozymes. In this study, LOXs 2 and 3 were purified and used to generate hydroperoxide (HPOD) products in an in vitro system using linoleic acid as a substrate in the presence of either air or O2. The products were analyzed to determine their stereoisomeric characteristics. The control (no enzyme) showed only low levels of hydroperoxide production and no stereoisomeric specificity. LOX 2 shows high specificity in product formation, producing roughly 4 times more 13-HPOD than 9-HPOD, nearly all of which was 13-S(Z,E)-HPOD. LOX 3 produced more 9-HPOD than 13-HPOD at approximately a 2:1 ratio. No single stereoisomer was predominant among LOX 3 products. These results demonstrate that different isozymes of LOX have characteristic product profiles in in vitro reactions.  相似文献   

Winter flocking behaviour of speckled warblers and the Allee effect     

Janet L Gardner 《Biological conservation》2004,118(2):195-204

The aggregation of individuals into foraging flocks is one behavioural trait that, if disrupted, can cause the Allee effect, which is a slowing in population growth at low density or small population size, and this can greatly increase the risk of extinction. Here, I describe intraspecific flocking behaviour of a colour-banded population of speckled warblers, Chthonicola sagittata, a species that has declined across a large part of its range in the fragmented temperate woodlands of Australia. I make predictions about the context in which the Allee effect might be expressed and the consequences for the viability of populations living in small habitat remnants. Speckled warblers lived in discrete, stable social groups throughout winter, the nucleus of which was the residents from one or more adjacent breeding territories. The timing and mode of flock formation and the size of flocks varied between two winters, apparently in response to the severity of conditions; thus flocking probably facilitates increased foraging efficiency and predator detection, potentially leading to increased survival in harsh conditions. Because flock territories were up to 30 ha each, and larger territories are likely, birds living in remnants smaller than 40 ha may suffer increased mortality if there are too few birds available to form flocks of an appropriate size to facilitate the benefits of grouping when conditions are most extreme. Further, in small remnants where survival is reduced, dominance behaviour and male-male competition may act to compound the Allee effect by reducing reproductive success. Regardless of these predictions, speckled warbler populations may only be viable in remnants that are large enough to support multiple flocks, to enable rapid recruitment to breeding vacancies and thus provide adequate numbers of birds for flocking.  相似文献   

The pacific century     

Gardner DP 《Science (New York, N.Y.)》1987,237(4812):233

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EDGAR ALLEN     

Gardner WU 《Science (New York, N.Y.)》1943,97(2521):368-369

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Laser ablation and the production of polymer films     

Blanchet GB  Fincher CR  Jackson CL  Shah SI  Gardner KH 《Science (New York, N.Y.)》1993,262(5134):719-721

The formation of high-quality thin films of polytetrafluoroethylene (PTFE) is important in many applications ranging from material reinforcement to molecular electronics. Laser ablation, a technique widely used to deposit a variety of inorganic materials, can also be used as a simple and highly versatile method for forming thin polymer films. The data presented show that PTFE films can be produced on various supports by the evaporation of a solid PTFE target with a pulsed ultraviolet laser. The composition of the ablation plume suggests that PTFE ablation and subsequent film formation occur by way of a laser-induced pyrolitic decomposition with subsequent repolymerization. The polymer films produced by this method are composed of amorphous and highly crystalline regions, the latter being predominantly in a chain-folded configuration with the molecular axis aligned parallel to the substrate surface.  相似文献   

Freedom and rules: the acquisition and reprogramming of a bird's learned song     

Gardner TJ  Naef F  Nottebohm F 《Science (New York, N.Y.)》2005,308(5724):1046-1049

Canary song is hierarchically structured: Short stereotyped syllables are repeated to form phrases, which in turn are arranged to form songs. This structure occurs even in the songs of young isolates, which suggests that innate rules govern canary song development. However, juveniles that had never heard normal song imitated abnormal synthetic songs with great accuracy, even when the tutor songs lacked phrasing. As the birds matured, imitated songs were reprogrammed to form typical canary phrasing. Thus, imitation and innate song constraints are separate processes that can be segregated in time: freedom in youth, rules in adulthood.  相似文献   

Removal of meteoric iron on polar mesospheric clouds     

Plane JM  Murray BJ  Chu X  Gardner CS 《Science (New York, N.Y.)》2004,304(5669):426-428

Polar mesospheric clouds are thin layers of nanometer-sized ice particles that occur at altitudes between 82 and 87 kilometers in the high-latitude summer mesosphere. These clouds overlap in altitude with the layer of iron (Fe) atoms that is produced by the ablation of meteoroids entering the atmosphere. Simultaneous observations of the Fe layer and the clouds, made by lidar during midsummer at the South Pole, demonstrate that essentially complete removal of Fe atoms can occur inside the clouds. Laboratory experiments and atmospheric modeling show that this phenomenon is explained by the efficient uptake of Fe on the ice particle surface.  相似文献   

Structural basis of a phototropin light switch     

Harper SM  Neil LC  Gardner KH 《Science (New York, N.Y.)》2003,301(5639):1541-1544

Phototropins are light-activated kinases important for plant responses to blue light. Light initiates signaling in these proteins by generating a covalent protein-flavin mononucleotide (FMN) adduct within sensory Per-ARNT-Sim (PAS) domains. We characterized the light-dependent changes of a phototropin PAS domain by solution nuclear magnetic resonance spectroscopy and found that an alpha helix located outside the canonical domain plays a key role in this activation process. Although this helix associates with the PAS core in the dark, photoinduced changes in the domain structure disrupt this interaction. We propose that this mechanism couples light-dependent bond formation to kinase activation and identifies a signaling pathway conserved among PAS domains.  相似文献