An Aboriginal Australian genome reveals separate human dispersals into Asia     

Rasmussen M  Guo X  Wang Y  Lohmueller KE  Rasmussen S  Albrechtsen A  Skotte L  Lindgreen S  Metspalu M  Jombart T  Kivisild T  Zhai W  Eriksson A  Manica A  Orlando L  De La Vega FM  Tridico S  Metspalu E  Nielsen K  Ávila-Arcos MC  Moreno-Mayar JV  Muller C  Dortch J  Gilbert MT  Lund O  Wesolowska A  Karmin M  Weinert LA  Wang B  Li J  Tai S  Xiao F  Hanihara T  van Driem G  Jha AR  Ricaut FX  de Knijff P  Migliano AB  Gallego Romero I  Kristiansen K  Lambert DM  Brunak S  Forster P  Brinkmann B  Nehlich O  Bunce M  Richards M  Gupta R 《Science (New York, N.Y.)》2011,334(6052):94-98

We present an Aboriginal Australian genomic sequence obtained from a 100-year-old lock of hair donated by an Aboriginal man from southern Western Australia in the early 20th century. We detect no evidence of European admixture and estimate contamination levels to be below 0.5%. We show that Aboriginal Australians are descendants of an early human dispersal into eastern Asia, possibly 62,000 to 75,000 years ago. This dispersal is separate from the one that gave rise to modern Asians 25,000 to 38,000 years ago. We also find evidence of gene flow between populations of the two dispersal waves prior to the divergence of Native Americans from modern Asian ancestors. Our findings support the hypothesis that present-day Aboriginal Australians descend from the earliest humans to occupy Australia, likely representing one of the oldest continuous populations outside Africa.  相似文献   

The metamorphosis of supernova SN 2008D/XRF 080109: a link between supernovae and GRBs/hypernovae     

Mazzali PA  Valenti S  Della Valle M  Chincarini G  Sauer DN  Benetti S  Pian E  Piran T  D'Elia V  Elias-Rosa N  Margutti R  Pasotti F  Antonelli LA  Bufano F  Campana S  Cappellaro E  Covino S  D'Avanzo P  Fiore F  Fugazza D  Gilmozzi R  Hunter D  Maguire K  Maiorano E  Marziani P  Masetti N  Mirabel F  Navasardyan H  Nomoto K  Palazzi E  Pastorello A  Panagia N  Pellizza LJ  Sari R  Smartt S  Tagliaferri G  Tanaka M  Taubenberger S  Tominaga N  Trundle C  Turatto M 《Science (New York, N.Y.)》2008,321(5893):1185-1188

The only supernovae (SNe) to show gamma-ray bursts (GRBs) or early x-ray emission thus far are overenergetic, broad-lined type Ic SNe (hypernovae, HNe). Recently, SN 2008D has shown several unusual features: (i) weak x-ray flash (XRF), (ii) an early, narrow optical peak, (iii) disappearance of the broad lines typical of SN Ic HNe, and (iv) development of helium lines as in SNe Ib. Detailed analysis shows that SN 2008D was not a normal supernova: Its explosion energy (E approximately 6x10(51) erg) and ejected mass [ approximately 7 times the mass of the Sun (M(middle dot in circle))] are intermediate between normal SNe Ibc and HNe. We conclude that SN 2008D was originally a approximately 30 M(middle dot in circle) star. When it collapsed, a black hole formed and a weak, mildly relativistic jet was produced, which caused the XRF. SN 2008D is probably among the weakest explosions that produce relativistic jets. Inner engine activity appears to be present whenever massive stars collapse to black holes.  相似文献   

Superconducting vortices in CeCoIn5: toward the Pauli-limiting field     

Bianchi AD  Kenzelmann M  Debeer-Schmitt L  White JS  Forgan EM  Mesot J  Zolliker M  Kohlbrecher J  Movshovich R  Bauer ED  Sarrao JL  Fisk Z  Petrovic C  Eskildsen MR 《Science (New York, N.Y.)》2008,319(5860):177-180

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Long-term effects of alternative and conventional fertilization I: Effects on arbuscular mycorrhizal fungi community composition     

Tancredo Augusto Feitosa de Souza  Andrea Fernandes Rodrígues  Luciano Façanha Marques 《Russian Agricultural Sciences》2015,41(6):454-461

The influence of long-term fertilization on arbuscular mycorrhizal fungi community composition was investigated. Soil samples were taken from a long-term field experiment which was conducted for 5 years to explore the effect of three treatments: control (non-fertilization), conventional (mineral fertilizers—NPK), and alternative (organic fertilizers—farmyard manure). The highest values of AMF community composition were found in the alternative fertilization system after the thirty year of its utilization. After the thirty year the conventional fertilization system showed lower AMF diversity compared to alternative fertilization system. In conclusion the alternative fertilization system enhanced mycorrhizal effectiveness that contributes to increase wheat growth after a long-term experiment. Our findings also suggest that inputs of organic matter source can change positively the AMF community composition, and these results highlight the importance of considering the long-term effect of mineral and organic fertilizers on the AMF community diversity. Thus, the long-term utilization of an alternative fertilization system with continuous input of organic matter may exploit positive situations of jointly beneficial biotic and abiotic conditions.  相似文献   

Cooking quality of Oregon-grown Russet potatoes     

Andrea Mackey  Joy Stockman 《American Journal of Potato Research》1958,35(5):395-407

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Protein haze formation in white wines: effect of saccharomyces cerevisiae cell wall components prepared with different procedures     

Lomolino G  Curioni A 《Journal of agricultural and food chemistry》2007,55(21):8737-8744

Cell wall material was extracted by five different methods from an oenological strain of Saccharomyces cerevisiae. Enzyme preparations containing beta-glucanase activity (Zymolyase, Glucanex, and Finizym 250L) allowed a better extraction yield compared to that of dithiothreitol (DTT) and EDTA. The yeast extracts were only soluble in part in wine. The wine-soluble fraction (WSF) of the five extracts, differing in both protein and sugar contents, when added in increasing amounts to white wine differently affected protein haze formation, as determined by the heat test, giving dose/response curves of different shapes. The curves obtained with the WSF derived from DDT and Zymolyase extracts showed a plateau value corresponding to 90% and 80% of wine haze reduction, respectively. In contrast, addition of the WSF derived from the other extracts resulted in increased turbidity with respect to the original wine. The mannoproteins (MP), isolated from each yeast extract by Concanavalin-A chromatography, gave dose/response curves showing shapes more similar among them than those obtained with the whole WSFs. The best wine stabilization was obtained with the MP of the DTT and Zymolyase extracts. The supernatants obtained after heating the MP of the different extracts were also tested. The stabilizing effect of the heat-stable MP (HSMP) was always larger than that of the corresponding total (un-heated) MP. The HSMP obtained starting from the DTT and Zymolyase extracts showed the best haze-protecting effect, which was, however, lower than that obtained with their corresponding WSF. This result suggests that wine protein stabilization by compounds of the yeast cell wall could be related, in addition to the action of the MP, also to the presence of other substances of different nature.  相似文献   

Effect of cold storage and packaging material on the major aroma components of sweet cream butter   总被引：3，自引：0，他引：3  

Lozano PR  Miracle ER  Krause AJ  Drake M  Cadwallader KR 《Journal of agricultural and food chemistry》2007,55(19):7840-7846

The major aroma compounds of commercial sweet cream AA butter quarters were analyzed by GC-olfactometry and GC-MS combined with dynamic headspace analysis (DHA) and solvent-assisted flavor evaporation (SAFE). In addition, the effect of long-term storage (0, 6, and 12 months) and type of wrapping material (wax parchment paper vs foil) on the aroma components and sensory properties of these butters kept under refrigerated (4 degrees C) and frozen (-20 degrees C) storage was evaluated. The most intense compounds in the aroma of pasteurized AA butter were butanoic acid, delta-octalactone, delta-decalactone, 1-octen-3-one, 2-acetyl-1-pyrroline, dimethyl trisulfide, and diacetyl. The intensities of lipid oxidation volatiles and methyl ketones increased as a function of storage time. Refrigerated storage caused greater flavor deterioration compared with frozen storage. The intensity and relative abundance of styrene increased as a function of time of storage at refrigeration temperature. Butter kept frozen for 12 months exhibited lower styrene levels and a flavor profile more similar to that of fresh butter compared to butter refrigerated for 12 months. Foil wrapping material performed better than wax parchment paper in preventing styrene migration into butter and in minimizing the formation of lipid oxidation and hydroxyl acid products that contribute to the loss of fresh butter flavor.  相似文献   

Effects of Diffuse Colonization of Grape Berries by Uncinula necator on Bunch Rots, Berry Microflora, and Juice and Wine Quality     

Gadoury DM  Seem RC  Wilcox WF  Henick-Kling T  Conterno L  Day A  Ficke A 《Phytopathology》2007,97(10):1356-1365

ABSTRACT Production of grape (principally cultivars of Vitis vinifera) for high-quality wines requires a high level of suppression of powdery mildew (Uncinula necator syn. Erysiphe necator). Severe infection of either fruit or foliage has well-documented and deleterious effects upon crop and wine quality. We found that berries nearly immune to infection by U. necator due to the development of ontogenic resistance may still support diffuse and inconspicuous mildew colonies when inoculated approximately 3 weeks post-bloom. Fruit with diffuse mildew colonies appear to be healthy and free of powdery mildew in late-season vineyard assessments with the naked eye. Nonetheless, presence of these colonies on berries was associated with (i) elevated populations of spoilage microorganisms; (ii) increased evolution of volatile ethyl acetate, acetic acid, and ethanol; (iii) increased infestation by insects known to be attracted to the aforementioned volatiles; (iv) increased rotting by Botrytis cinerea; and (v) increased frequency of perceived defects in wines prepared from fruit supporting diffuse powdery mildew colonies. Prevention of diffuse infection requires extending fungicidal protection until fruit are fully resistant to infection. Despite a perceived lack of improvement in disease control due to the insidious nature of diffuse powdery mildew, potential deleterious effects upon crop and wine quality thereby would be avoided.  相似文献   

Chemical and microbial properties in a greenhouse loamy soil after steam disinfestation alone or combined with CaO addition     

Antonio Gelsomino  Beatrix Petrovi?ová  Andrea Peruzzi 《Soil biology & biochemistry》2010,42(7):1091-1100

Steam disinfestation represents an increasingly attractive strategy to control soil-borne pathogens and weeds both in greenhouses and field crops. Beyond pest control, steam injection has the potential to alter soil nutrient dynamics and composition of bacterial communities. This study investigated the impact of a soil-steaming method (the Bioflash™ system) on main chemical (total organic C, TOC; total N, TN; cation exchange capacity, CEC; exchangeable Na, K, Mg and Ca; KCl-extractable ammonium and nitrate, DTPA-exchangeable Mn) and microbial (microbial biomass C, MBC; genetic structure of bacterial communities) properties in a greenhouse loamy soil. Treatments were carried out by using a self-propelled soil-steaming machine operating at two steaming modes (deep or shallow) in combination or not with addition of an exothermically reacting compound (CaO at a 1000 kg ha⁻¹ rate). Soils from a five-treatment (NS, non-steamed soil, DS, deep steam injection; DS + E, deep steam injection plus CaO; SS, shallow steam injection; SS + E, shallow steam injection plus CaO) plot block were sampled before steaming and after 8, 19, 54 and 91 days. Compositional shifts in the structure of soil bacterial communities were monitored by denaturing gradient gel electrophoresis (DGGE) fingerprinting of soil-extracted 16S rRNA gene fragments, using primers specific for Bacteria and Actinobacteria. Maximum soil temperature reached 70 °C (DS) and 82 °C (DS + E) in the 10-20 cm layer; and 50 °C (SS) and 53 °C (SS + E) in the 0-10 cm layer. TOC, TN, CEC, exchangeable Na, Mg and Ca were not statistically affected by soil steaming, CaO addition, depth of injection or their interactions. Conversely, SS promoted a large release of exchangeable K, notwithstanding CaO addition. Steam disinfestation significantly stimulated ammonium release, which further increased in CaO-treated steamed soils. Generally ammonium and nitrate pools varied oppositely, being the latter markedly reduced at the end of the observation period. Available Mn was significantly increased by soil steaming, but it was depressed when steaming was combined with CaO addition. Soil steaming markedly reduced the MBC, especially in DS-treated and SS-treated plots. The genetic structure of soil bacterial and actinobacterial communities was largely unresponsive to the steaming treatments. Even though the Bioflash™ system did not cause bacterial eradication or compositional shifts in bacterial community structure, soil steaming stimulated an increased release of soluble nutrients (K⁺, Mn²⁺, NH₄⁺-N). Over a longer perspective, excessive soil resources exploitation and potential risks of Mn toxicity should be cautiously considered especially in repeatedly (and eventually acid) steamed soils.  相似文献   

Cutaneous lesions in pet rabbits following subcutaneous administration of a novel bivalent vaccine against myxomatosis and rabbit haemorrhagic disease     

Paolo Selleri  Nicola Di Girolamo  Andrea Vögtlin  Ivan Fileccia  Richard Hoop  Laura Bongiovanni 《Veterinary dermatology》2014,25(6):563-e100

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