Massive-star supernovae as major dust factories     

Sugerman BE  Ercolano B  Barlow MJ  Tielens AG  Clayton GC  Zijlstra AA  Meixner M  Speck A  Gledhill TM  Panagia N  Cohen M  Gordon KD  Meyer M  Fabbri J  Bowey JE  Welch DL  Regan MW  Kennicutt RC 《Science (New York, N.Y.)》2006,313(5784):196-200

We present late-time optical and mid-infrared observations of the Type II supernova 2003gd in the galaxy NGC 628. Mid-infrared excesses consistent with cooling dust in the ejecta are observed 499 to 678 days after outburst and are accompanied by increasing optical extinction and growing asymmetries in the emission-line profiles. Radiative-transfer models show that up to 0.02 solar masses of dust has formed within the ejecta, beginning as early as 250 days after outburst. These observations show that dust formation in supernova ejecta can be efficient and that massive-star supernovae could have been major dust producers throughout the history of the universe.  相似文献   

The effect on pathogenesis of Newcastle disease virus LaSota strain from a mutation of the fusion cleavage site to a virulent sequence     

Wakamatsu N  King DJ  Seal BS  Peeters BP  Brown CC 《Avian diseases》2006,50(4):483-488

The principal molecular determinant of virulence of Newcastle disease virus (NDV) is the amino acid sequence at the fusion cleavage activation site. To extend the understanding of the role of the fusion cleavage activation site in NDV virulence, the pathogenesis in chickens of a lentogenic LaSota isolate and two infectious clones, NDFL and NDFLtag, were compared. NDFL is an infectious clone of a lentogenic NDV strain (LaSota E13-1), and NDFLtag is the infectious clone with the fusion cleavage site sequence mutated to the virulent motif. NDFL and NDFLtag were described by Peeters et al. The viruses were inoculated intraconjunctivally into groups of 4-wk-old white leghorn chickens and compared in a pathogenesis study for determination of disease causation (clinical signs of disease, gross lesions, histology, virus isolation, and serology) and viral distribution (presence of viral nucleoprotein and mRNA was detected by immunohistochemistry and in situ hybridization, respectively). The modification of the fusion cleavage activation site to the virulent motif in the infectious clone only slightly increased disease severity and viral distribution in the pathogenesis assessment, even though dramatically increased pathogenicity of NDFLtag was confirmed by standard pathogenicity index tests. The result, that the mutated fusion cleavage site of NDV-NDFLtag had only a small influence on pathogenesis in chickens compared to either E13-1 or NDFL, suggests that the pathogenic effects of NDV are not dependent on the fusion cleavage site alone.  相似文献   

Effect of industrial dehydration on the soluble carbohydrates and dietary fiber fractions in legumes     

Martín-Cabrejas MA  Aguilera Y  Benítez V  Molla E  López-Andréu FJ  Esteban RM 《Journal of agricultural and food chemistry》2006,54(20):7652-7657

The effects of soaking, cooking, and industrial dehydration treatments on soluble carbohydrates, including raffinose family oligosaccharides (RFOs), and also on total dietary fiber (TDF), insoluble dietary fiber (IDF), and soluble (SDF) dietary fiber fractions were studied in legumes (lentil and chickpea). Ciceritol and stachyose were the main alpha-galactosides for chickpea and lentil, respectively. The processing involved a drastic reduction of soluble carbohydrates of these legumes, 85% in the case of lentil and 57% in the case of chickpea. The processed legume flours presented low residual levels of alpha-galactosides, which are advisable for people with digestive problems. Processing of legumes involved changes in dietary fiber fractions. A general increase of IDF (27-36%) due to the increase of glucose and Klason lignin was observed. However, a different behavior of SDF was exhibited during thermal dehydration, this fraction increasing in the case of chickpea (32%) and decreasing in the case of lentil (27%). This is probably caused by the different structures and compositions of the cell wall networks of the legumes.  相似文献   

Dexmedetomidine or medetomidine premedication before propofol-desflurane anaesthesia in dogs     

Gómez-Villamandos RJ  Palacios C  Benítez A  Granados MM  Domínguez JM  López I  Ruiz I  Aguilera E  Santisteban JM 《Journal of veterinary pharmacology and therapeutics》2006,29(3):157-163

The objective of this study was to evaluate dexmedetomidine as a premedicant in dogs prior to propofol-desflurane anaesthesia, and to compare it with medetomidine. Six healthy dogs were anaesthetized. Each dog received intravenously (i.v.) five preanaesthetic protocols: D1 (dexmedetomidine, 1 microg/kg, i.v.), D2 (dexmedetomidine, 2 microg/kg, i.v.), M1 (medetomidine, 1 microg/kg, i.v.), M2 (medetomidine, 2 microg/kg, i.v.), or M4 (medetomidine, 4 microg/kg, i.v.). Anaesthesia was induced with propofol (2.3-3.3 mg/kg) and maintained with desflurane. The following variables were studied: heart rate (HR), mean arterial pressure, systolic arterial pressure, diastolic arterial pressure, respiratory rate (RR), arterial oxygen saturation, end-tidal CO2, end-tidal concentration of desflurane (EtDES) required for maintenance of anaesthesia and tidal volume. Arterial blood pH (pHa) and arterial blood gas tensions (PaO2, PaCO2) were measured during anaesthesia. Time to extubation, time to sternal recumbency and time to standing were also recorded. HR and RR decreased significantly during sedation in all protocols. Cardiorespiratory variables during anaesthesia were statistically similar for all protocols. EtDES was significantly different between D1 (8.1%) and D2 (7.5%), and between all doses of medetomidine. Desflurane requirements were similar for D1 and M2, and for D2 and M4 protocols. No statistical differences were observed in recovery times. The combination of dexmedetomidine, propofol and desflurane appears to be effective for induction and maintenance of general anaesthesia in healthy dogs.  相似文献   

Does the world really need more babies?     

Zuckerman B 《Science (New York, N.Y.)》2006,313(5795):1885-1886

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The consensus coding sequences of human breast and colorectal cancers     

Sjöblom T  Jones S  Wood LD  Parsons DW  Lin J  Barber TD  Mandelker D  Leary RJ  Ptak J  Silliman N  Szabo S  Buckhaults P  Farrell C  Meeh P  Markowitz SD  Willis J  Dawson D  Willson JK  Gazdar AF  Hartigan J  Wu L  Liu C  Parmigiani G  Park BH  Bachman KE  Papadopoulos N  Vogelstein B  Kinzler KW  Velculescu VE 《Science (New York, N.Y.)》2006,314(5797):268-274

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Detection of Dickeya spp. latent infection in potato seed tubers using PCR or ELISA and correlation with disease incidence in commercial field crops under hot‐climate conditions     

L. Tsror  O. Erlich  M. Hazanovsky  B. Ben Daniel  U. Zig  S. Lebiush 《Plant pathology》2012,61(1):161-168

Over a 5‐year period (2006–2010), 277 certified, visually healthy potato seed lots, imported from Europe to Israel for commercial use, were tested for Dickeya spp. latent infection by PCR analysis (277 seed lots) and ELISA (154 seed lots). Seeds from these lots were grown in commercial potato fields which were inspected twice a season by Plant Protection and Inspection Services (PPIS). Stem samples were tested for the presence of Dickeya spp. by PCR analysis. PCR and ELISA results from seed lot testing correlated with disease expression in 74 and 83·8% of the cases, respectively. Positive laboratory results with no disease symptoms in the field (‘+lab/?field’ results) comprised 24·7 and 9·7% of the PCR and ELISA analyses, respectively, whereas negative laboratory results with disease symptoms in the field results (‘?lab/+field’) were obtained in 1·3 and 6·5%, of cases respectively. Maximum disease incidence, as well as the number of cultivars expressing disease symptoms, increased over the years of this study, indicating an increase in the prevalence of the disease. Severe disease incidence was observed on cvs Dita, Rodeo, Desiree, Mondial, Tomensa and Jelly. Of the 55 imported seed lots from which disease was recorded in the field, 49 originated from the Netherlands, four from Germany and two from France. None originated from Scotland.  相似文献   

An Asian ambrosia beetle Euwallacea fornicatus and its novel symbiotic fungus Fusarium sp. pose a serious threat to the Israeli avocado industry     

Z. Mendel  A. Protasov  M. Sharon  A. Zveibil  S. Ben Yehuda  K. O’Donnell  R. Rabaglia  M. Wysoki  S. Freeman 《Phytoparasitica》2012,40(3):235-238

The ambrosia beetle, Euwallacea fornicatus Eichhoff, was first recorded in Israel in 2009. The symbiotic fungus Fusarium sp., carried in mycacangia located in the anterior region of the female head, is responsible for the typical wilt symptoms inflicted on avocado (Persea americana Miller) trees. The beetle?Cfungus complex has become a serious threat to the future of the avocado industry in Israel.  相似文献   

Genetic relationships and hybrid vigour in olive (Olea europaea L.) by microsatellites     

Iris Biton  Sofia Shevtsov  Oren Ostersetzer  Yair Mani  Shimon Lavee  Benjamin Avidan  Giora Ben‐Ari 《Plant Breeding》2012,131(6):767-774

The olive (Olea europaea) is one of the most important oleaginous crops of the Mediterranean basin. Increased demand for olive oil creates a need for new olive varieties to help meet the requirements of the global market. However, olive breeding has been handicapped by such varied challenges as a prolonged juvenile period, agrotechnical problems and insufficient genetic knowledge. The use of DNA markers has the potential to overcome these problems and increase the effectiveness of classical breeding programmes. In this study, co‐dominant polymorphic simple sequence repeats (SSRs) were used as markers to analyse the genetic relationships between several local and other ‘non‐native’ olive cultivars. Cluster analysis revealed four major groups among the 15 cultivars examined in this study. Table and oil cultivars were clustered in different groups. However, the clusters did not differentiate between cultivars of different geographical origins. In addition, we used the data gathered to analyse genetic relationships to evaluate the effects of heterosis in agricultural traits. Genetic distances between cultivars were determined based on the SSR genotype data and were used for evaluating the possible effects of heterosis in various F₁ populations. Interestingly, phenotypic data of F₁ progenies from crosses between different cultivars indicated the potential effects of heterosis as expressed in several traits. Genetic distance between parents was significantly correlated to F₁ performance for three traits: percentage of dry fruit weight, oil content and commercial oil production. Thus, crosses between olive cultivars exhibiting relatively extensive genetic distances one from the other are expected to result in better progeny performance in future Olea breeding programmes. Our study linked assessment of biodiversity of commercial olive cultivars with the application of this information in olive breeding programmes for selection of specific parents to generate superior new cultivars.  相似文献   

黄牛FSHR基因的生物信息学分析   总被引：3，自引：1，他引：2  

王明亮  陈鹏  郝明超  高旭东  刘犇  余四九 《甘肃农业大学学报》2012,47(4):7-13

利用生物基因组学数据库,对黄牛FSHR基因进行生物信息学分析,以预测FSHR基因编码产物的理化性质、结构与功能,同时构建FSHR同源系统进化树.结果表明:FSHR基因编码产物为疏水性跨膜蛋白,具有明显的信号肽,其切割位点位于17～18位的氨基酸之间,二级结构主要以α-螺旋与无规则卷曲为主,并主要在质膜中发挥生物学作用,跨膜区域分为跨膜域、胞外域和胞内域3个部分.序列分析表明,FSHR编码产物可能具有离子通道、运载体、受体、信号转导和阳离子通道等功能,在离子跨膜与信号传递过程中发挥重要作用,并对黄牛的激素调节有影响.FSHR基因编码产物系统进化树表明,黄牛FSHR与水牛、成都麻羊、绵羊等物种FSHR遗传距离较近,具有高度同源性.  相似文献