Nano-silver pulse treatments inhibit stem-end bacteria on cut gerbera cv. Ruikou flowers   总被引：2，自引：0，他引：2  

Jiping Liu  Shenggen He  Zhaoqi Zhang  Jinping Cao  Peitao Lv  Sudan He  Guiping Cheng  Daryl C. Joyce 《Postharvest Biology and Technology》2009,54(1):59-62

Nanometer-sized silver (Ag⁺) particles (NS) are used in various applications as an anti-microbial. Effects of NS (2–5 nm diam.) pulse solution treatments on vase life of cut gerbera (Gerbera jamesonii) cv. Ruikou flowers were investigated. Compared with the control [pulsed with deionised water (DI) and subsequently held in DI] pulsing for 24 h with 5 mg/L NS solution followed by holding in DI maintained water uptake and extended vase life. From in vitro and microscopy assessments, NS pulse treatment inhibited bacteria growth in the vase solution and at cut stem ends during the first 2 d of the vase period.  相似文献   

Strategies for educational action to meet veterinary medicine's role in biodefense and public health     

Baker J  Blackwell M  Buss D  Eyre P  Held JR  Ogilvie T  Pappaioanou M  Sawyer L 《Journal of veterinary medical education》2003,30(2):164-172

It is clear that the profession is not well prepared to respond to society's needs in bio-defense and public health. The imperatives that face the veterinary profession, as emphasized by the agenda for action conference deliberations that are reported in this issue of the journal, require action on many fronts, but possibly none more essential than to address how veterinary education needs to change to meet these challenges. Addressing these needs, participants at the agenda for action conference met in groups of 30 to 50 to shape approaches that would address these key questions. The 161 participants were broadly representative of government, private practice, corporate practice, organized veterinary medicine, and academia (Appendix A). Reported here are the results of those deliberations, with each of the seven sections written up by the discussion leader. Included in the participants were 20 students, representative of eight different veterinary colleges, who both participated in the group discussions and have presented their own report.  相似文献   

Survival of foals with experimentally induced Rhodococcus equi infection given either hyperimmune plasma containing R. equi antibody or normal equine plasma     

Perkins GA  Yeager A  Erb HN  Nydam DV  Divers TJ  Bowman JL 《Veterinary therapeutics : research in applied veterinary medicine》2002,3(3):334-346

The purpose of this study was to determine if colostrum-deprived foals with experimentally induced Rhodococcus equi pneumonia have a decreased severity of the disease and decreased mortality rate when given hyperimmune (HI) R. equi antibody plasma (R. equi titer at least 100 % and virulence-associated protein A [VapA] at least 10000) prophylactically versus when given normal equine plasma (R. equi titer less than 20 % and VapA less than 160). Sixteen colostrum-deprived foals (R. equi titer less than 5 %) each received normal equine plasma in the first 24 hours of life (R. equi titer less than 20 %). At 14 days of age, six foals were given normal equine plasma and 10 foals were given HI plasma. All foals were subsequently infected intrabronchially with a pathogenic strain of R. equi (2.5 x 10 sup 8; organisms) at 21 days of age. Repeated physical examinations, weight measurements, complete blood cell counts, fibrinogen measurements, and thoracic radiographs (ventrodorsal and lateral) were performed to help determine the severity of the disease. Foals given HI plasma had significantly higher R. equi ELISA titers (42.4 %) than those given normal plasma (20.9 %) on the day of experimental infection. Mortality rates and severity of disease were statistically similar (P >.05) for the groups. Although none of the foals was treated with antibiotics, several with severe R. equi pneumonia recovered. Either HI or normal equine plasma administered to foals in the first few weeks of life caused no adverse effects and may be protective against R. equi, although the exact constituent responsible for protection is undetermined and requires further investigation.  相似文献   

Effect of postmortem storage on activity of mu- and m-calpain in five bovine muscles     

Camou JP  Marchello JA  Thompson VF  Mares SW  Goll DE 《Journal of animal science》2007,85(10):2670-2681

An in situ system involving incubation of 60- to 80-g pieces of muscle at 4 degrees C under different conditions was used to determine the effects of time of postmortem storage, of pH, and of temperature on activities of mu- and m-calpain activity in bovine skeletal muscle. Casein zymograms were used to allow measurement of calpain activity with a minimum of sample preparation and to ensure that the calpains were not exposed to ionic strengths of 100 or greater before assay of their activities. In 4 of the 5 muscles (longissimus dorsi, lumbar; longissimus dorsi, thoracic; psoas major; semimembranosus; and triceps brachii) studied, mu-calpain activity decreased nearly to zero within 48 h postmortem. Activity of m-calpain also decreased in the in situ system used but at a much slower rate. Activities of both mu- and m-calpain decreased more slowly in the triceps brachii muscle than in the other 4 muscles during postmortem storage. Although previous studies have indicated that mu-calpain but not m-calpain is proteolytically active at pH 5.8, these studies have used calpains obtained from muscle at death. Both mu- and m-calpain are proteolytically inactive if their activities are measured at pH 5.8 and after incubating the muscle pieces for 24 h at pH 5.8. Western analysis suggested that neither the large 80-kDa subunit nor the small 28-kDa subunit of m-calpain was autolyzed during postmortem storage of the muscle pieces. As has been reported previously, the 80-kDa subunit of mu-calpain was autolyzed to 78- and then to a 76-kDa polypeptide after 7 d postmortem, but the 28-kDa small subunit was not autolyzed; hence, the autolyzed mu-calpain molecule in postmortem muscle is a 76-/28-kDa molecule and not a 76-/18-kDa molecule as previously assumed. Because both subunits were present in the postmortem calpains, loss of mu-calpain activity during postmortem storage is not due to dissociation of the 2 subunits and inactivation. Although previous studies have shown that the 76-/18-kDa mu-calpain molecule is completely active proteolytically, it is possible that the 76-/28-kDa mu-calpain molecule in postmortem muscle is proteolytically inactive and that this accounts for the loss of mu-calpain activity during postmortem storage. Because neither mu- nor m-calpain is proteolytically active at pH 5.8 after being incubated at pH 5.8 for 24 h, other proteolytic systems such as the caspases may contribute to postmortem proteolysis in addition to the calpains.  相似文献   

Different cultures,different values: The role of cultural variation in public’s WTP for marine species conservation     

Adriana Ressurreição  James Gibbons  Michel Kaiser  Tomaz Ponce Dentinho  Tomasz Zarzycki  Charlotte Bentley  Melanie Austen  Daryl Burdon  Jonathan Atkins  Ricardo S. Santos  Gareth Edwards-Jones 《Biological conservation》2012,145(1):148-159

Understanding the cultural variation in public preference for marine species is a necessary pre-requisite if conservation objectives are to include societal preferences in addition to scientific considerations. We report the results of a contingent study undertaken at three case-study sites: Azores islands (Portugal), Gulf of Gdansk (Poland) and Isles of Scilly (UK). The study considered species richness of five specific marine taxa (mammals, birds, fish, invertebrates and algae) as proxies of marine biodiversity and the aim of analysis was to estimate from a multi-site perspective public’s willingness to pay (WTP) to avoid increased levels of species loss (reduction of species richness) for different marine taxa. Results, based on 1502 face-to-face interviews, showed that income, education and environmental awareness of the respondents were significant predictors of WTP for marine species conservation. Results also indicated that respondents in each of the European locations had different preferences for marine taxa. In the Azores, although mammals and fish were valued highly, small differences occurred in the WTP among different taxa. Respondents in the Isles of Scilly put a relatively low value on fish while algae and marine mammals were highly valued. In Gdansk, respondents defined a clear order of preference for marine mammals > fish > birds > invertebrates and algae. These findings suggested that cultural differences may be important drivers of valuation and undermines the commonly held premise that charismatic/likeable taxa consistently have a disproportionately strong influence on WTP for biodiversity conservation. We conclude that conservation policy must take account of cultural diversity alongside biological diversity.  相似文献   

Analysis of yield variability in winter wheat due to temporal variability,and nitrogen and phosphorus fertilization     

Kefyalew Girma  Kyle W. Freeman  Roger Teal  Daryl B. Arnall  Brenda Tubana  Starr Holtz 《Archives of Agronomy and Soil Science》2013,59(4):435-442

Abstract

Field average based recommendations have been a common practice for recommending the major crop nutrients nitrogen (N) and phosphorus (P). The problem is yield will not be the same from year to year with application of the same amount of recommended rate of fertilizer. The objectives of this study were to demonstrate how recommendations generated using nutrient response experiments were dynamic; and to assess the relative contribution of temporal variability, N and P fertilizers on winter wheat grain yield and N concentration. Twelve factorial combinations of four N (0, 56, 112, and 168 kg ha^?1) and three P (0, 14.5, and 29 kg P ha^?1) rates were evaluated in a randomized complete block design with three replications at Perkins, Oklahoma. To address the first objective, ANOVA and orthogonal polynomial contrasts were used. To address the second objective, a ten predictor variable multiple linear regression model with two quantitative variables and their interaction (N, P and N×P) and seven-year variables was evaluated and a reduced model containing seven variables was generated. Wheat grain yield showed three distinct responses to N rates: Linear, quadratic and no response. These individual year data show that it is not always appropriate to use results of nutrient response experiments to estimate next year's N fertilizer requirement due to apparent temporal variability in the results. Wheat only responded to P during the first two years of the study. The reduced model from the regression analysis revealed that most of the variability in grain yield was accounted for by five individual indicator years and N only. High variability across years in grain yield and fertilizer (N and P) response, even between years of similar grain yield, is an indication of a given season's production dependence on factors other than N and P.  相似文献   

Evaluation of frost resistant tuber-bearing solanum hybrids     

Daryl G. Richardson  Nelson Estrada Ramos 《American Journal of Potato Research》1971,48(9):339-343

Frost resistance of interspecific and varietal potato crosses was evaluated at Bogotá, Colombia using intact plants in a programmed low temperature growth cabinet. Plants were exposed to a 2 hour frost during the dark period and the minimum test temperature was successively lowered 1 C on subsequent nights. The foliage was visually scored for damage 10–12 hours after each frost. While most commercial varieties were killed at—2 to—3 C (28 to 26 F), 101 of 121 clones which have been bred specifically for frost resistance survived to at least—5 C (23 F) and some crosses resisted—9 C (16 F) without observable foliar damage. This suggests the possibility of obtaining cultivated varieties from varietal parents of cultivated species such as G. Andigena, G. Phureja, G. Stenotomum,S. ajanhuiri, and others, which are reasonably frost resistant.  相似文献   

Copper distribution and ionic form effects for postharvest treatments of cut Acacia holosericea stems     

Kamani Ratnayake  Chuc L. Bui  Daryl C. Joyce 《Scientia Horticulturae》2011

A short postharvest life is the major constraint associated with cut Acacia flowers and foliage. Treatment with CuSO₄ (Cu²⁺) has previously been shown to improve the longevity of cut Acacia holosericea stems. Towards refining the treatments, a range of Cu²⁺ and Cu⁺ salts were assessed for relative efficacy in improving vase life and water relations of A. holosericea. Five hour pulses with the Cu²⁺ salts CuSO₄, CuCl₂, (CH₃COO)₂Cu and Cu(NO₃)₂ at 2.2 mM gave equally longer vase lives by ∼2.5-fold over deionised water (DIW) and standard tap water (STW) controls. The same Cu²⁺ salts at 0.5 mM in the vase solution also gave significantly (P < 0.05) improved vase life, relative fresh weight and water uptake compared to the DIW control. For Cu²⁺ versus Cu⁺, optimum concentrations with Cu²⁺ could not be directly compared due to the low solubility of the Cu⁺ salt CuCl. However, Cu⁺ from CuCl at 0.415 mM also had positive effects on vase life compared to the DIW control. Thus, both Cu²⁺ and Cu⁺ treatments can enhance vase life parameters for cut A. holosericea foliage. The benefits were irrespective of the counter ion and, thus, Cu²⁺ and Cu⁺per se were responsible. The most effective Cu²⁺ pulse treatment decreased stomatal conductance of phyllodes initially, but did not cause sustained stomatal closure. Cu accumulated to greater levels in basal stem and phyllode tissues than in upper stem and phyllode tissues of cut A. holosericea stems. Possible mechanisms of Cu²⁺/Cu⁺ action are discussed.  相似文献   

小麦谷蛋白聚合体粒度分布与面粉揉面特性关系的研究   总被引：9，自引：0，他引：9  

赵惠贤  胡胜武  吉万全  薛秀庄  郭蔼光  Daryl Mares 《中国农业科学》2001,34(5):475-479

 选用在谷蛋白 Glu- 1和 Glu- 3的 5个位点 (除 Glu- A1位点外 )上均带有不同等位基因的小麦品种 Suneca和 Cook的杂交 F4 代群体中谷蛋白各亚基位点均为纯合基因的 60个系 ,测定基因型不同的系间谷蛋白聚合体粒度分布和面粉揉面特性的变异 ,研究小麦谷蛋白聚合体粒度分布与面粉揉面特性的关系。结果表明 ,不同的谷蛋白基因型 ,其谷蛋白聚合体粒度大小相对分布 (即 U PP% )和面团形成时间 (即揉面曲线图峰值的和面时间 ,PTM)均有显著差异。面粉的揉面曲线形状与其 U PP%值密切相关 ,U PP%与 PTM呈极显著正相关 ,与揉面曲线图峰高 ( PHM)呈显著负相关 ;与面粉蛋白质含量 ( FP% )相比 ,U PP%对 PTM和 PHM的影响更大些 ,可作为育种早代品质性状选择的一个指标  相似文献   

Drought and high temperature increases preharvest sprouting tolerance in a genotype without grain dormancy     

T.?B.?BiddulphEmail author  D.?J.?Mares  J.?A.?Plummer  T.?L.?Setter 《Euphytica》2005,143(3):277-283

Preharvest sprouting is common in cereals, which lack grain dormancy when maturing grain is exposed to rainfall or high moisture conditions. Environmental conditions such as drought and high temperature during grain filling have a large effect on the expression of sprouting tolerance. A dormant (DM 2001) and non-dormant (Cunderdin) hard white spring wheat were exposed to drought or irrigated conditions and either low or high temperature during grain filling. Dormancy and embryo sensitivity to ABA were analysed throughout grain filling. The conclusions from this investigation were as follows; firstly DM 2001 was more dormant than Cunderdin, with a four-fold lower germination index (GI) at maturity. Secondly during grain ripening drought increased dormancy and overrides any increase in dormancy with low temperature. Finally embryo sensitivity can be induced in a non-dormant genotype to the extent where the non-dormant genotype in a hot dry environment can have the same phenotype as a dormant genotype grown in a cool wet environment. In summary drought during grain filling increases dormancy suggesting breeders need to avoid drought when screening for sprouting tolerance in order to maximise the chances of identifying genetic differences in grain dormancy and avoid any maturity by drought interactions.  相似文献