Replacing Soybean Meal with Alternative Protein Sources in Diets for Pond‐raised Hybrid Catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus

The present study investigated the replacement of soybean meal with combinations of two or three alternative protein sources in diets for pond‐raised hybrid catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus. Alternative protein sources evaluated included cottonseed meal, distillers dried grains with solubles (DDGS), peanut meal, and porcine meat and bone meal (PMBM). Hybrid catfish fingerlings with a mean initial weight of 35 g/fish were stocked into 25 earthen ponds (0.04 ha) at a density of 14,826 fish/ha. Fish were fed once daily to apparent satiation for 166 d. No significant differences were observed for total diet fed, net yield, weight gain, survival, carcass yield, fillet yield, or fillet proximate composition among dietary treatments. Results show soybean meal may be completely replaced by combinations of cottonseed meal and one or two other alternative protein sources including DDGS, peanut meal, and PMBM in the diet without markedly affecting production and processing characteristics and fillet proximate composition of pond‐raised hybrid catfish. These alternative diets may be used during foodfish production when prices are favorable.     

Comparison of the effects of salicylic acid and ethephon with virus-induced hypersensitivity and acquired resistance in tobacco

The induction of a hypersensitive reaction in Samsun NN tobacco by tobacco mosaic virus (TMV) at 20°C leads to the development of both localized and systemic acquired resistance, and is associated with the appearance of pathogenesis-related proteins (PR's) and large increases in peroxidase activity and ethylene production. Salicylic acid (SA) induced a similar resistance in treated plant parts and occasionally also in untreated upper leaves of plants of which three lower leaves had been injected. SA also induced the same four PR's, but these were confined to the treated leaves. Thus, the connection between the presence of PR's and the reduction of TMV multiplication and spread may not be direct.In contrast to TMV, SA did not stimulate ethylene production and hardly increased peroxidase activity. Induction of acquired resistance and PR's by SA developed equally well at 20°C and at 32°C. However, pricking leaves with needles moistened with the ethylene-releasing compound ethephon mimicked TMV infection in inducing acquired resistance and PR's in both treated and untreated leaves at 20°C, but not at 32°C. Ethephon increased peroxidase activity at both temperatures, but only at 20°C dit it induce changes in both the anodic and the cathodic isoenzymes that were similar to those induced as a result of TMV infection. SA induced PR's and reduced TMV multiplication in Samsun tobacco, and inhibited virus spread in Samsun NN at 32°C.These observation indicate that neither the induction of PR's, nor the development of acquired resistance is temperature-sensitive. On the other hand, the effects of ethephon are temperature-sensitive in the same way as the hypersensitive response to TMV. It can thus be hypothesized that ethylene, produced naturally during the hypersensitive reaction of tobacco to TMV, leads to the temperature-sensitive synthesis or release of a presumably benzoic acid-type compound that functions as the natural inducer of PR's and acquired resistance. Although vanillic acid has been shown to accumulate in hypersensitively reacting tobacco leaves, it produced none of the effects of SA, and thus cannot be the natural inducer.Samenvatting Inductie van een overgevoeligheidsreactie in Samsun NN-tabak door tabaksmozaïekvirus (TMV) bij 20°C leidt tot de ontwikkeling van een verworven resistentie die zowel lokaal als systemisch werkzaam is, en gaat samen met het verschijnen van pathogenesis-related proteins (PR's) en sterke toename in de activitieit van peroxidase en de produktie van ethyleen. Salicylzuur (SA) induceerde een vergelijkbare resistentie in behandelde plantedelen en af en toe ook in niet behandelde bovenbladeren van planten waarvan drie onderbladeren waren ingespoten. SA induceerde ook dezelfde vier PR's, maar deze waren beperkt tot de behandelde bladeren. Er bestaat dus geen directe samenhang tussen de aanwezigheid van PR's en de remming van de vermeerdering en uitbreiding van TMV in de plant.In tegenstelling tot TMV stimuleerde SA de ethyleenproduktie niet en verhoogde het de peroxidaseactiviteit nauwelijks. Inductie van verworven resistentie en PR's door SA trad even goed op bij 32°C als bij 20°C. Net als infectie met TMV leidde aanprikken van bladeren met naalden die gedoopt waren in een oplossing van ethefon — waaruit in het blad ethyleen vrijkomt — echter tot inductie van verworven resistentie en PR's in zowel behandelde als onbehandelde bladeren bij 20°C, maar niet bij 32°C. Ethefon verhoogde de peroxidaseactiviteit bij beide temperaturen, maar alleen bij 20°C induceerde het veranderingen in zowel de anodische als de kathodische isoënzymen die vergelijkbaar waren met die welke geïnduceerd werden als gevolg van infectie met TMV. SA induceerde PR's en verminderde de vermenigvuldiging van TMV in Samsun tabak, en remde de uitbreiding van het virus in Samsun NN bij 32°C.Deze waarnemingen tonen dat noch de inductie van PR's, noch de ontwikkeling van verworven resistentie een temperatuurgevoelig proces is. Daarentegen zijn de effecten van ethefon op dezelfde wijze temperatuurgevoelig als de overgevoeligheidsreactie op TMV. Men kan daarom veronderstellen dat ethyleen, dat op natuurlijke wijze geproduceerd wordt tijdens de overgevoeligheidsreactie van tabak op TMV, aanleiding geeft tot een temperatuurgevoelig proces, namelijk de synthese of het vrijkomen van een verbinding, vermoedelijk een benzoëzuurderivaat, dat fungeert als de natuurlijke inductor van PR's en verworven resistentie. Hoewel is aangetoond dat vanillinezuur zich ophoopt in overgevoelig reagerende tabaksbladeren, veroorzaakte deze verbinding geen enkel van de effecten van SA. Vanillinezuur kan dus niet de natuurlijke inductor zijn.     

解淀粉芽胞杆菌JDF-6液态发酵条件优化及抑菌蛋白的分析

为探讨解淀粉芽胞杆菌JDF-6液体发酵条件及抑菌蛋白性质,以菌量和抑菌蛋白粗提液活性为指标,采用单因素和正交试验对菌株的最适发酵培养基成分及发酵条件进行优化,同时通过硫酸铵沉淀法提取抑菌蛋白粗提液,并进行稳定性试验。结果表明,菌株JDF-6最适培养基配比为3.0%蔗糖,1%酵母粉,2%茶渣饼,0.3%硫酸锰;最适发酵条件为发酵时间120 h,发酵温度30℃,初始p H 6.5~7.0,接种量5%,250 m L装液量为100 m L。优化后菌株JDF-6抑菌活性提高51.6%,经50%饱和度硫酸铵沉淀获得的抑菌蛋白的粗提液对蛋白酶、高温(100℃以上)、紫外光(光照8 h以上)敏感,抑菌活性均下降。     

格氏线虫表皮蛋白和分泌蛋白抑制昆虫免疫活性的比较

格氏线虫表皮蛋白和分泌蛋白都具有抑制昆虫免疫反应的能力,能够帮助侵染期线虫侵染寄主,但两者所含蛋白组分并不相同,从而导致蛋白活性也有所差异。本研究采用乙醇萃取和昆虫匀浆诱导,分别从侵染期的格氏线虫体表及分泌物中得到了表皮蛋白和分泌蛋白,并比较了这两者之间的异同。结果表明,无论是在昆虫体内还是体外,侵染期线虫表皮蛋白和分泌蛋白都具有抑制昆虫免疫反应的生物活性,并且分泌蛋白的活性更强。本研究为进一步研究线虫侵染与昆虫免疫间的相互关系和线虫抑制昆虫免疫反应的作用机理提供了科学佐证。     

苏云金杆菌杀虫晶体蛋白作用机制的研究进展

自本世纪６０年代以来,由于化学农药引起的环境污染、害虫普遍产生抗药性等原因,生物防治越来越受到人们的重视。在现有的各种生物防治策略中,研究和利用微生物杀虫剂发展很快,最突出的方法是利用苏云金杆菌（Ｂａｃｉｌｕｓｔｈｕｒｉｎｇｉｅｎｓｉｓ,Ｂｔ）进行防...     

Pathogenesis-related gene expression in rice is correlated with developmentally controlled Xa21-mediated resistance against Xanthomonas oryzae pv. oryzae

Disease resistance mediated by the resistance gene Xa21 is developmentally controlled in rice. We examined the relationship between Pathogenesis Related (PR) defense gene expression and Xa21-mediated developmental disease resistance induced by Xanthomonas oryzae pv. oryzae (Xoo). OsPR1a, OsPR1b, and OsPR1c genes were cloned and their induction was analyzed, in addition to the OsPR10a gene, at the juvenile and adult stages in response to a wildtype Xoo strain that induces a resistance response (incompatible interaction) and an isogenic mutant Xoo strain that does not (compatible interaction). We found that the adult stage leaves are more competent to express these OsPR1 genes and that the Xa21 locus is required for the highest levels of induction.     

Activation of systemic disease resistance in pea by an avirulent bacterium or a benzothiadiazole, but not by a fungal leaf spot pathogen

Inoculation of first expanded leaves of pea seedlings with an avirulent strain of Pseudomonas syringae pv. pisi , or treatment with sprays of a benzothiadiazole (20 or 100  μ g a.i. mL⁻¹), decreased the susceptibility of subsequent leaves 7 or 14 days later to challenge inoculation with Mycosphaerella pinodes . Inoculation of first leaves with a virulent strain of P. syringae pv. pisi or with M. pinodes did not decrease the susceptibility of plants to M. pinodes . Treatments effective in decreasing susceptibility to M. pinodes were similarly active against Uromyces viciae-fabae and virulent P. syringae pv. pisi . Effective treatments also enhanced the activities of the enzymes β-1,3-glucanase and chitinase in untreated upper leaves 6 days later. Ineffective treatments for decreased susceptibility had no effect on the activity of the enzymes. None of the treatments enhanced peroxidase activities. The results are discussed in relation to the reported signalling effects of the benzothiadiazole and in relation to a suggested high activity of the avirulent P. syringae pv. pisi strain and inactivity of M. pinodes in enhancing natural signalling.     

商陆抗病毒蛋白在植物抗病上的应用

商陆抗病毒蛋白是指商陆属植物中的核糖体失活蛋白.阐述了商陆抗病毒蛋白的研究历史、意义、种类和理化性质,对病原菌的抗性、抗病机理及其在植物抗病上的应用情况等,并对它的应用前景作了展望.     

Brown Macroalgae (Phaeophyceae): A Valuable Reservoir of Antimicrobial Compounds on Northern Coast of Spain

The search for new sources of antimicrobial compounds has become an urgent need, due to the threat that the spread of bacterial resistance represents for global health and food safety. Brown macroalgae have been proposed as a great reservoir in the search for novel antimicrobial compounds. In this study, mid-polarity extracts were performed with a selection of 20 brown macroalgae species from northern Spain. The total polyphenol, carbohydrate and protein contents were quantified by spectrophotometry. The volatile organic compounds (VOCs) of whole macroalgae were also studied as a biomarker of their metabolic state in the representative species of the tested families by gas chromatography-mass spectrometry (GC-MS). The antimicrobial potential of the extracts was assessed by a disk diffusion assay against 20 target bacteria and further determinations of the minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) were performed by a microdilution assay for the active extracts. Ericaria selaginoides, Bifurcaria bifurcata and Dictyota dichotoma showed an antimicrobial effect against six Gram-positive strains: Bacillus cereus, Bacillus subtilis, Geobacillus stearothermophilus, Listeria monocytogenes, Staphylococcus aureus and Staphylococcus haemolyticus. The phenolic content was generally higher in the extracts that showed antimicrobial activity, followed by carbohydrates and low contents of proteins. The results obtained in this study reveal the potential of brown macroalgae as a promising alternative source of antimicrobial compounds as functional ingredients for the application in industrial fields.     

利用iTRAQ蛋白质组技术筛选与鸡喙畸形相关的候选蛋白

【目的】中国地方鸡种如北京油鸡、清远麻鸡存在喙畸形现象,表现为上下喙咬合不全,呈交叉状。严重影响鸡饮水和采食,从而影响个体发育和生产性能的发挥,造成一定经济损失。笔者根据喙畸形个体的系谱记录,发现喙畸形的形成受到遗传因素的影响,但具体机制尚不明确。蛋白是行使各种生物学功能的最终形式之一,喙畸形个体的发生可能是由于核心蛋白或者相关调控蛋白代谢异常造成的。利用同位素标记相对和绝对定量（isobaric tags for relative and absolute quantitation,iTRAQ）技术以及生物信息学分析方法,筛选鸡畸形喙与正常喙中差异表达的蛋白,作为喙畸形相关的重要候选蛋白,为进一步研究北京油鸡喙畸形的遗传机制奠定基础。【方法】挑选3只120日龄喙畸形的公鸡作为试验组,编号为W1、W2、W3,同时,挑选与试验组个体为同胞关系（全同胞或半同胞）的喙正常公鸡作为对照组,编号为Z1、Z2、Z3。将喙畸形与其同胞正常个体作为一个比对组,iTRAQ试验具体包含3个比对组,即W1 vs Z1,W2 vs Z2,W3 vs Z3。屠宰个体后,剔除喙组织周围肌肉和筋膜,分离得到喙上颌骨和下颌骨,提取总蛋白样品,应用6个 iTRAQ标签标记各蛋白样品,经过色谱层析预分离,联合液相串联质谱分析,采用Mascot 2.3.02软件对蛋白进行鉴定和定量分析。试验组（W）与其同胞对照组(Z)样本比较（W1 vs Z1,W2 vs Z2,W3 vs Z3）,选择肽段数≥2,表达差异值＞1.2（上调）或＜0.83（下调）,且P＜0.05的蛋白作为差异表达蛋白。【结果】利用iTRAQ技术一共在喙组织中鉴定到3 372个蛋白,鉴定到的特异性肽段有12 769个。其中原鸡蛋白1 869个,分子质量主要分布在10-100 kD之间。3个比对组共鉴定出159个表达量有显著差异的蛋白质,其中包含70个表达上调的蛋白,89个表达下调的蛋白。统计各比对组蛋白表达差异值发现,表达量差异较大的上调蛋白质有LPL、MLC-2、CO9A1、MATN3、HSP90B1等,表达量差异较大的下调蛋白质有MBP、RLA1、PRVM、HAPLN1等。结合已经报道的这些蛋白的生物学功能,其中CO9A1、MATN3、HAPLN1与软骨合成和软骨骨化相关,CO9A1是带状软骨纤维的组成物质,MATN家族是非胶原性细胞外基质蛋白家族,HAPLN1是软骨细胞外基质的重要组成成分;PRVM是细胞内钙离子结合蛋白,参与调控Ca2+离子信号通路;LPL是多功能酶,主要在脂质代谢和转运过程中起作用,参与调控PPAR信号通路。初步筛选出CO9A1、MATN3、HAPLN1、PRVM、LPL作为与鸡喙畸形相关的候选蛋白。【结论】差异表达蛋白的发现为鸡喙畸形形态的发生提供蛋白质水平上的理论依据。