Genetic Parameters of Disease Incidence,Fertility and Milk Yield of First Parity Cows and the Relation to Feed Intake of Growing Bulls     

R. Wassmuth  D. Madsen  P. Jensen  P. Jensen 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(2):93-102

Abstract

Not much is known about the effect of light sources on behavioural development of laying hens. The effect of natural and artificial light, respectively, on feeding and perching of layers was studied. 126-day-old chicks were divided into 1) A8: 8h artificial light+16h darkness, 2) A16: 16h artificial light+8h darkness, 3) N8: 8h daylight+16h darkness. A8 and N8 birds did not differ in their feeding behaviour, whereas the mean proportion of A16 birds feeding was 0.056 lower than in A8 birds in daytime (P<0.001) and 0.019 lower in nighttime (P<0.0001). N8 birds tended to start nighttime perching earlier than A8 birds (hazard ratio=8.5; P=0.056). These results suggest that chicks can change their feeding behaviour depending on day length. Natural daylight was found to precipitate the onset of nighttime perching in the life of the pullet.  相似文献   

轻轨(地下段)振动环境影响分析及应用实例     

刘德敏  任建锋 《绿色科技》2013,(8):256-258

指出了振动环境影响评价是城市轨道交通建设项目环境影响评价的重点评价专题,剖析了轻轨(地下段)振动环境影响评价重点值得关注的几个问题,结合实例进一步探讨了城市快速轨道交通对环境振动产生的影响,为污染防治提供依据。  相似文献   

杭州七格污水处理厂紫外线消毒系统的运行分析     

李松  白月芬  李岚 《绿色科技》2013,(8):227-230

对杭州七格污水处理厂三期工程的紫外消毒系统的运行情况进行了系统分析。结果表明:该紫外消毒系统的设计规模为60万t/d;紫外消毒系统的运行效果受进水透光率和进水悬浮物浓度的影响;工程运行期间,依据紫外消毒系统进水水质情况,调整消毒设备运行方案,变化紫外灯管的运行数量,消毒效果较为理想,经过紫外消毒系统后的出水粪大肠菌群数除特殊几天外均能达到设计的出水标准。  相似文献   

论农业经济的特点及作用     

马晶晶  姜双双 《绿色科技》2013,(8):287-290

指出了农业是人类的衣食之源,生存之本,是国民经济其他部门独立和进一步发展的基础。农业问题是当前中国最大的经济问题,因为农业问题解决得好与不好,不仅关系到国民经济的发展,而且关系到我们在2020年能否实现全面建设小康社会的宏伟目标,能否推进社会主义现代化的建设。结合我国的实际情况分析我国农业的特点,利用简单的Excel工具,通过数据剖析我国农业的作用,最后得出结论:在推进工业化进程中,农业对国民经济的贡献虽然有所下降,但是它是发展工业化,走现代化道路的基石,它的基础性地位不可动摇。  相似文献   

A methodology for characterization and analysis of plant functional composition in grassland‐based farms     

M. Duru  L. Hossard  G. Martin  J. P. Theau 《Grass and Forage Science》2013,68(2):216-227

Understanding the relationships between farmers' land‐use and management decisions, and plant diversity is a challenge. It requires characterization of plant diversity within and between fields and investigation of land‐use allocation to fields. To analyse how grassland functional composition [mean plant trait and functional diversity index (FD)] varies according to scale (field, land‐use type: cutting, grazing, farm), grasslands were characterized according to leaf dry‐matter content (leaf DM) and FD computed from leaf DM values. A leaf DM‐αFD framework was used to analyse how leaf DM‐based plant strategies were distributed at land‐use type and farm scales (βFD). The study was conducted on eight dairy and beef farms (169 grasslands) differing in their stocking rate. At field and land‐use type scales, leaf DM was significantly decreased and increased with N fertilizer rate and field elevation respectively. It was significantly higher for grazing than for cutting. At the farm scale, the main differences between farms resulted from differences in plant strategy distribution between land‐use types within a farm and among farms for a given land‐use type in relation to management intensity. Farms that contributed the most to αFD had the highest stocking rate, and those which had the most contrasting grasslands for management intensity had the highest βFD. Management practices need to be examined at a land‐use type scale for evaluating the within‐ and between‐field plant functional compositions. By contrast, the value of the analysis was reduced if data were collected and averaged at the farm scale.  相似文献   

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?     

Alejandro M. S. Mayer  Abimael D. Rodríguez  Orazio Taglialatela-Scafati  Nobuhiro Fusetani 《Marine drugs》2013,11(7):2510-2573

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.  相似文献   

“Head-to-Side-Chain” Cyclodepsipeptides of Marine Origin     

Marta Pelay-Gimeno  Judit Tulla-Puche  Fernando Albericio 《Marine drugs》2013,11(5):1693-1717

Since the late 1980s, a large number of depsipeptides that contain a new topography, referred to as “head-to-side-chain” cyclodepsipeptides, have been isolated and characterized. These peptides present a unique structural arrangement that comprises a macrocyclic region closed through an ester bond between the C-terminus and a β-hydroxyl group, and terminated with a polyketide moiety or a more simple branched aliphatic acid. This structural pattern, the presence of unique and complex residues, and relevant bioactivity are the main features shared by all the members of this new class of depsipeptides, which are reviewed herein.  相似文献   

Antibacterial Activity of Long-Chain Polyunsaturated Fatty Acids against Propionibacterium acnes and Staphylococcus aureus     

Andrew P. Desbois  Keelan C. Lawlor 《Marine drugs》2013,11(11):4544-4557

New compounds are needed to treat acne and superficial infections caused by Propionibacterium acnes and Staphylococcus aureus due to the reduced effectiveness of agents used at present. Long-chain polyunsaturated fatty acids (LC-PUFAs) are attracting attention as potential new topical treatments for Gram-positive infections due to their antimicrobial potency and anti-inflammatory properties. This present study aimed to investigate the antimicrobial effects of six LC-PUFAs against P. acnes and S. aureus to evaluate their potential to treat infections caused by these pathogens. Minimum inhibitory concentrations were determined against P. acnes and S. aureus, and the LC-PUFAs were found to inhibit bacterial growth at 32–1024 mg/L. Generally, P. acnes was more susceptible to the growth inhibitory actions of LC-PUFAs, but these compounds were bactericidal only for S. aureus. This is the first report of antibacterial activity attributed to 15-hydroxyeicosapentaenoic acid (15-OHEPA) and 15-hydroxyeicosatrienoic acid (HETrE), while the anti-P. acnes effects of the six LC-PUFAs used herein are novel observations. During exposure to the LC-PUFAs, S. aureus cells were killed within 15–30 min. Checkerboard assays demonstrated that the LC-PUFAs did not antagonise the antimicrobial potency of clinical agents used presently against P. acnes and S. aureus. However, importantly, synergistic interactions against S. aureus were detected for combinations of benzoyl peroxide with 15-OHEPA, dihomo-γ-linolenic acid (DGLA) and HETrE; and neomycin with 15-OHEPA, DGLA, eicosapentaenoic acid, γ-linolenic acid and HETrE. In conclusion, LC-PUFAs warrant further evaluation as possible new agents to treat skin infections caused by P. acnes and S. aureus, especially in synergistic combinations with antimicrobial agents already used clinically.  相似文献   

Dithiolopyrrolone Natural Products: Isolation,Synthesis and Biosynthesis     

Zhiwei Qin  Sheng Huang  Yi Yu  Hai Deng 《Marine drugs》2013,11(10):3970-3997

Dithiolopyrrolones are a class of antibiotics that possess the unique pyrrolinonodithiole (4H-[1,2] dithiolo [4,3-b] pyrrol-5-one) skeleton linked to two variable acyl groups. To date, there are approximately 30 naturally occurring dithiolopyrrolone compounds, including holomycin, thiolutin, and aureothricin, and more recently thiomarinols, a unique class of hybrid marine bacterial natural products containing a dithiolopyrrolone framework linked by an amide bridge with an 8-hydroxyoctanoyl chain linked to a monic acid. Generally, dithiolopyrrolone antibiotics have broad-spectrum antibacterial activity against various microorganisms, including Gram-positive and Gram-negative bacteria, and even parasites. Holomycin appeared to be active against rifamycin-resistant bacteria and also inhibit the growth of the clinical pathogen methicillin-resistant Staphylococcus aureus N315. Its mode of action is believed to inhibit RNA synthesis although the exact mechanism has yet to be established in vitro. A recent work demonstrated that the fish pathogen Yersinia ruckeri employs an RNA methyltransferase for self-resistance during the holomycin production. Moreover, some dithiolopyrrolone derivatives have demonstrated promising antitumor activities. The biosynthetic gene clusters of holomycin have recently been identified in S. clavuligerus and characterized biochemically and genetically. The biosynthetic gene cluster of thiomarinol was also identified from the marine bacterium Pseudoalteromonas sp. SANK 73390, which was uniquely encoded by two independent pathways for pseudomonic acid and pyrrothine in a novel plasmid. The aim of this review is to give an overview about the isolations, characterizations, synthesis, biosynthesis, bioactivities and mode of action of this unique family of dithiolopyrrolone natural products, focusing on the period from 1940s until now.  相似文献   

Trypanocidal Activity of Marine Natural Products     

Amy J. Jones  Tanja Grkovic  Melissa L. Sykes  Vicky M. Avery 《Marine drugs》2013,11(10):4058-4082

Marine natural products are a diverse, unique collection of compounds with immense therapeutic potential. This has resulted in these molecules being evaluated for a number of different disease indications including the neglected protozoan diseases, human African trypanosomiasis and Chagas disease, for which very few drugs are currently available. This article will review the marine natural products for which activity against the kinetoplastid parasites; Trypanosoma brucei brucei, T.b. rhodesiense and T. cruzi has been reported. As it is important to know the selectivity of a compound when evaluating its trypanocidal activity, this article will only cover molecules which have simultaneously been tested for cytotoxicity against a mammalian cell line. Compounds have been grouped according to their chemical structure and representative examples from each class were selected for detailed discussion.  相似文献