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排序方式: 共有3311条查询结果,搜索用时 15 毫秒
1.
Thirty-two crossbred cattle (steers = 17; heifers = 15) exhibiting an ultrasound fat thickness at the 12 to 13th rib region of at least 10 mm were selected from a slaughter shift at a commercial packing plant. After splitting, alternating sides of each carcass were trimmed of 1) subcutaneous fat in excess of 6.4 mm; 2) all kidney, pelvic, and heart fat; and 3) all cod or udder fat and fat in the flank region. Both sides of each carcass were fabricated into subprimals (final trim level of 6.4 mm) according to normal industry procedures. Effect of hot-fat trimming, yield grade (3, 4, and 5), and gender on hot-fat trim, fabrication fat trim, major subprimal, and total subprimal yield of untrimmed and trimmed carcasses were determined. Higher numerical yield grade (YG) corresponded with higher (P less than .05) percentages of hot-fat trim. Hot-fat trimming increased (P less than .05) the difference in fabrication fat trim between steers and heifers and between YG 3 and YG 5. Steers and heifers differed (P less than .05) in percentage of major subprimals and total subprimals when processed conventionally, whereas hot-fat trimming eliminated this difference (P less than .05). Untrimmed YG 3 carcasses had 3.1 and 5.0% higher major subprimal yield (P less than .05) than untrimmed YG 4 and YG 5 carcasses, respectively, whereas hot-fat trimming reduced this difference to 2.5% for YG 4 and to 3.7% for YG 5.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
2.
Tropical Animal Health and Production - Avian influenza virus (AIV) H9N2 subtype is endemic in Iran and causes substantial economic loss to the growing poultry industry within the country. In this...  相似文献   
3.
Lipolytic enzymes catalyze the hydrolysis and synthesis of ester compounds. They are valuable in the pulp, food, and textile industries. This study aims to comprehensively evaluate the extreme properties of a hormone-sensitive lipase (EstATII-TM) isolated from the Red Sea Atlantis II brine pool. EstATII-TM was cloned, expressed, and its biochemical activities were assessed under different conditions. EstATII-TM catalytic properties and resistance to different metal ions were compared to commercial thermophilic esterases under different temperatures. Phylogenetically, EstATII-TM was assigned to the GDSAG motif subfamily of hormone-sensitive lipase. The optimal enzyme activity was evident at a temperature of 30 °C and pH 7–8. The enzyme retained 84.9% of its activity at 0.5 M NaCl. EstATII-TM maintained 93% to 97% activity at −40 and −20 °C, respectively. EstATII-TM activity was significantly enhanced, up to 10-fold, at temperatures ranging from 45 to 65 °C in the presence of 1 mM Cu2+, Cd2+, Ba2+, Mn2+, and Zn2+. EstATII-TM showed superior catalytic activity and resistance-to/enhancement-by metal ions compared to two commercial thermophilic esterases. The Red Sea Atlantis II brine EstATII-TM is characterized by tolerance to high temperatures, stability to hot and cold conditions, as well as toxic heavy metal contamination, making it an ideal candidate for industrial processes.  相似文献   
4.
Marine bio-sourced chitosan nanoparticles (CSNP) are antimicrobial and immunomodulatory agents beneficial for fish medicine. Herein, dietary CSNP was investigated for the amelioration of the systemic inflammatory responses of an induced fish model. One hundred and forty-four rainbow trout were assigned to one pathogen-free and non-supplemented group (negative control), and three challenged groups: non-supplemented (positive control), CSNP-preventive, and CSNP-therapeutic. After a feeding experiment extended for 21 days, the organosomatic indices (OSI) and molecular aspects were assessed. After a challenge experiment extended for further 28 days, CSNP-therapeutic intervention was assessed on fish survival and systemic inflammatory responses on pathology, histo-morphology, and molecular aspects. With CSNP administration, OSI nonsignificantly decreased and the relative expression of targeted inflammatory-mediator genes was significantly increased. The CSNP-therapeutic fish showed an RPS of 80% as compared to the positive control group, and CSNP-therapeutic administration retained the highest gene expression augmentation up to 28 days after the challenge. Notably, the splenic reticulin fibers framework of the CSNP-therapeutic group retained the highest integrity among the groups during the infection. After recovery, reticulin fibers density in the CSNP-therapeutic samples was significantly higher than in the negative control group, which indicates high innate immunity. Thus, CSNP showed promising biotherapeutic features enhancing fish resistance against infections.  相似文献   
5.
Several members of the bacterial genus Brenneria are pathogenic on different tree species. Cell-free extracts from the bacterial phytopathogens Brenneria rubrifaciens, B. salicis, and B. nigrifluens induced production of the red pigment rubrifacine in the B. rubrifaciens bruI insertional mutant Br-212. Analysis of the bruI locus identified an adjacent open reading frame, designated bruR, with homology to luxR. High-performance liquid chromatography and mass spectrometry analysis of ethyl acetate extracts from wild-type B. rubrifaciens and Escherichia coli expressing the bruI gene identified two acyl homoserine lactone (AHL) peaks, N-(3-oxohexanoyl)-homoserine lactone (3OC6HSL) and N-hexanoyl-homoserine lactone (C6HSL). Addition of synthetic 3OC6HSL and C6HSL at 10 μM to the bruI mutant, strain Br-212, induced rubrifacine production and the ability to elicit a hypersensitive reaction (HR) in tobacco leaves. Synthetic C6HSL was less effective at inducing pigment production than 3OC6HSL at 10 μM. The bruI mutant Br-212 did not produce detectable AHLs, indicating that C6HSL and 3OC6HSL are the major AHLs produced by this species. The AHLs N-heptanoyl-DL-homoserine lactone (C7HSL), N-octanoyl-DL-homoserine lactone (C8HSL), and N-(3-oxooctanoyl)-DL-homoserine lactone (3OC8HSL) also induced pigment production in Br-212 and restored its ability to elicit an HR in tobacco, suggesting that cross-talk with other bacterial species may be possible.  相似文献   
6.
以电生功能水为研究对象,采用喷雾施药方法,研究了不同有效氯浓度的电功能水对南瓜果腐病防治效果。试验结果表明,电生功能水对南瓜果腐病的防治效果随有效氯含量的增加而提高,当电生功能水有效氯浓度为95 mg/L时效果最佳,防效达82.94%,与对照药剂50%多菌灵可湿性粉剂的防效89.41%不存在显著性差异。  相似文献   
7.
中国果树类病毒的发生及其研究进展(英文)   总被引:4,自引:0,他引:4  
王国平  洪霓  Ahmed Hadidi 《果树学报》2005,22(1):51-54,F003
概述了在中国发生且己鉴定明确的5种果树类病毒,即苹果绣果类病毒(Apple scar skin viroid,ASSVd)、梨泡状溃疡类病毒(Pear blister canker viroid,PBCVd)、葡萄黄斑类病毒-1(Grapevine yellow speckle viroid-1,GYSVd-1)、柑橘裂皮类病毒(Citrus exocortis viroid,CEVd)和桃潜隐花叶类病毒(Peachlatent mosaic viroid,PLMVd)的研究进展,包括病害的首次发现、症状特征、发病规律、检测方法与防治对策以及这些类病毒的生物学与分子生物学特性。  相似文献   
8.
为探究10%乙霉威·腐霉利微粉剂(有效成分质量分数:5%乙霉威,5%腐霉利)在设施黄瓜上施用后的沉积分布特性及残留消解动态,采用PC-3A(S)型激光粉尘仪及粉尘取样片,分别研究了不同设施类型、不同温湿度及不同施药角度下,10%乙霉威·腐霉利微粉剂在设施黄瓜上的沉积分布情况;并于2017年和2018年,分别在北京市进行了该药剂在设施黄瓜叶片和果实中的残留及消解动态试验。结果表明:不同设施类型、不同温度条件下,10%乙霉威·腐霉利微粉剂的沉积分布特性无明显差异,且其有效成分分解率不受温度影响;不同湿度条件下,该微粉剂在黄瓜叶片上的沉积量不同,湿度越大沉积量越多。乙霉威和腐霉利在黄瓜叶片和果实中的消解动态均符合准一级动力学或一级动力学方程,2种药剂在叶片中的半衰期分别为3.2 d和3.0~3.2 d,在果实中的半衰期分别为4.0~4.3 d和3.1~3.8 d。采用10%乙霉威·腐霉利微粉剂,分别按100 g/hm2和150 g/hm2(1.5倍)剂量于黄瓜幼果期施药,最多施药3次,施药间隔期为7 d,距最后一次施药间隔7、10和14 d分别采样,乙霉威在黄瓜果实中的最大残留量为0.88 mg/kg,低于中国国家标准规定的其最大残留限量(MRL)值(5 mg/kg),腐霉利在黄瓜果实中的最大残留量为0.49 mg/kg,也低于其MRL值(2 mg/kg)。该研究结果可为10%乙霉威·腐霉利微粉剂在设施黄瓜上的安全使用提供数据支持。  相似文献   
9.
为明确中国华北地区瓜类尖孢镰刀菌Fusarium oxysporum Schl.对咪鲜胺的抗药性现状及抗药突变株的生物学性状,采用菌丝生长速率法,分别测定了采自北京、山东、河北等地未使用过咪鲜胺的112株瓜类尖孢镰刀菌对咪鲜胺的敏感性,并通过药剂驯化的方法获得尖孢镰刀菌抗咪鲜胺突变株。结果表明:咪鲜胺对112株瓜类尖孢镰刀菌的平均EC50值为(0.030 1±0.030 4)μg/mL,菌株频率呈连续单峰曲线分布,未发现敏感性明显下降的亚群体,因此,可将该EC50值作为瓜类尖孢镰刀菌对咪鲜胺的敏感基线。药剂驯化共获得7株抗咪鲜胺突变株,其抗性倍数介于6.2~26.8之间;突变株在菌丝生长速率、菌丝干重和致病力等方面均明显低于亲本菌株,差异显著;仅突变株HG13052701-R1的抗药性可以稳定遗传,其他6株抗咪鲜胺突变株的抗药性均不能稳定遗传。室内交互抗性测定结果表明,咪鲜胺仅与戊唑醇之间有交互抗性,与多菌灵和齅霉灵之间均无交互抗性关系。研究表明,瓜类尖孢镰刀菌在药剂选择压下可以形成抗咪鲜胺群体,具有低等抗药性风险。  相似文献   
10.
Decision support systems (DSSs) are indispensable tools in preparing a forest management plan for a better combination of multiple forest values. This study attempted to develop and explain a stand-based forest management DSS (Ecosystem-based multiple-use forest planning [ETÇAP]) comprising a traditional simulation, linear programming (LP), metaheuristics and geographic information system. The model consists of five submodels; traditional management approach to handle inventory data, an empirical growth and yield model, a simulation to conceptualize management actions, a LP technique to optimize resource allocation and a simulated annealing approach to directly create a spatially feasible harvest schedule. The ETÇAP model has been implemented in a comparative two case study areas; Denizli–Honaz and Akseki–Ibrad?. Both simulation and optimization models outperformed to the traditional management plan. The periodical change of growing stock, allowable cuts, carbon sequestration and water production are used as performance indicators. The results showed that more amount of wood could be harvested over time compared to traditional level of harvesting. It could be concluded that various management strategies allowed managers to stimulate more decision options for better outputs through intertemporal trade-offs of management interventions as the model provided tools to quantify forest dynamics over time and space. Challenges exist to establish the functional relationships between forest structure and values for better quantification and integration into the management plans.  相似文献   
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