甜菜碱对断奶仔猪的作用效果及其机理探讨

１２０ 头“杜长加”断奶仔猪按饲养试验要求分成５ 组（每组３ 个重复,每一重复８ 头,公母各半）对照组饲以基础饲粮,试验饲粮在基础饲粮中分别添加６００,８００,１ ０００, １ ２００ ｍ ｇ／ｋｇ 甜菜碱试验为期３６ ｄ结果显示：不同剂量甜菜碱均提高了断奶仔猪的日采食量和日增重,降低了料重比 其中 ８００ｍ ｇ／ｋｇ 甜菜碱组效果最为显著,日采食量和日增重比对照组分别提高了８７１％ （Ｐ＜ ００５）和 １１８２％（Ｐ＜ ００５）,料重比降低２７９％ （Ｐ＜ ００５）;且显著降低了血清尿素氮含量（Ｐ＜ ００１）,提高了血清总铁结合力、生长激素和类胰岛素生长因子Ⅰ（ＩＧＦⅠ）水平（Ｐ＜ ００５）此外,添加８００ ｍ ｇ／ｋｇ 甜菜碱明显改变了断奶仔猪的胴体组成     

利用PCR检测柑桔黄龙病病原研究(英文)

对引起柑桔黄龙病的类菌原体（ＢＬＯ）的ＰＣＲ检测方法进行了研究．结果表明,利用ＰＣＲ方法不但能对ＢＬＯ、ＤＮＡ进行离体扩增,而且对各种不同来源的感病植物样品也能很好地进行检测．本文首次报道了从未显症的植物上用ＰＣＲ方法检测到了ＢＬＯ,技接试验证实了该方法的可靠性．正是由于本方法可在病原侵染早期进行检测这一优点,从而可控制带病苗木的扩散．该技术也可被用于无毒苗木的筛选,从而控制病害发生．该技术对ＢＬＯ引起的黄龙病的检测不但简单、有效而且实用     

Antimicrobial activity of partially characterized analytes from Bacillus pumilus(B2)

This study was carried out to characterize the antimicrobial substance produced by the strain of Bacillus pumilus (B2) obtained from Novozymes Biologicals Inc. to compare its antimicrobial activity by agar well diffusion assay and bacteriocin activity assay via critical dilution method against seven different strains of Vibrio spp., specifically V. alginolyticus (A01), V. cholerae (C01), V. fluvialis (F01, F02), V herveyii (H), V. mimicus (M01), V. parahaemolyticus (P01) and V. vulnificus (V01, V02). All Vibrio spp. were isolated from the hemolymph and intestine of the white faeces disease‐infected moribund pacific white‐leg shrimp Litopenaeus vannamei (Boone 1931) and one strain (V. harveyi) from its diseased postlarva. The cell‐free neutralized supernatant (CFNS) of B2 showed moderate thermo‐stability being stable up to 70°C for 60 min with, however, reducing activity above 80°C for 20 min. B2 antimicrobials showed a stable activity within the pH ranging from 6 to 10 at room temperature and at 4°C, while residual antimicrobial activity of crude CFNS showed tolerance to salinity up to 7% of sodium chloride below 4°C. No B2 activity was obtained while exposed to proteolytic enzyme, such as proteinase k and pepsin, while its activity kept stable exposed to lipase. Initial B2 characterization for antimicrobial substance in CFNS revealed proteinaceous in nature owing to activity loss against proteolytic enzymes and no lipid moiety activity against lipase, which could be categorized as bacteriocin‐like inhibitory substance having potential application against several strains of Vibrio spp. in aquaculture.     

Ultrastructural and biomolecular detection of Rickettsiales‐like organisms in tissues of rainbow trout with Red Mark Syndrome

Red mark syndrome (RMS) and US strawberry disease (US SD) are skin disorders affecting rainbow trout farmed in Europe and USA. The disease etiology has not yet been established. In spite of specific investigations, identifying Rickettsia‐like organism (RLO)‐ and Midichloria‐like organism (MLO)‐related DNA in affected individuals, these pathogens have never been observed. We performed histological, ultrastructural and biomolecular analysis on skin and spleen samples of trout with RMS. Examination by TEM revealed the presence of intracytoplasmic microorganisms resembling Rickettsiales within macrophages, fibroblasts and erythrocytes. The microorganisms were oval or short rod shaped (400–800 nm in length and 100–200 nm in width) and often showed a cell wall similar to Gram‐negative bacteria. PCR analysis for Rickettsiales supported these findings: 53% of affected trout were positive by both PCR and TEM The primers RiFCfw‐RiFCrev were used to anneal both the RLO 16S DNA sequence and the MLO 16S DNA sequence. For this reason, and in agreement with previous studies confirming the presence of Rickettsiales‐related DNA in trout with RMS, we assume that TEM detected microorganisms morphologically consistent with bacteria belonging to Rickettsiales order and could be considered as possible causative agents of RMS.     

浅谈古典园林欣赏

中国古典园林的造园论源于画论,强调立意;欣赏古典园林,应先欣赏其意境美和诗画文化     

土体构型对花岗岩红壤细沟发育形态的影响

为探究花岗岩红壤细沟形态特殊变化的原因，解释土体构型影响细沟形态发育的机理。设计单一红土层(H)、单一砂土层(S)、上红下砂层状土层(HS)3种土体构型、不同径流量(低径流量3 L/min、高径流量6 L/min)和不同坡度(中坡20°、陡坡40°)的室内模拟细沟冲刷试验。结果表明：H处理下，细沟形态更多向“V”形和“U”形发育；S处理下，细沟沟道发育过程中短暂形成上窄下宽的深宽梯形断面后，完全崩塌；HS处理下，细沟形态能发育为梯形断面，且能继续扩大发育。与H和S相比，HS陡坡(40°)处理下沟岸崩塌更加频繁且单次大质量崩塌更多。HS陡坡(40°)处理下沟岸崩塌发生21次，其中，单次崩塌量>1 kg的占比为63%。HS与H和S相比，雷诺数(Re)和弗罗德数(Fr)的波动更剧烈，更有利于梯形断面形成。与H、S相比，HS沟壁崩塌发生时，上层红土层含水量最低为0.31 cm³/cm³,抗剪强度最高为178 kPa;而下层砂土层含水量较高(0.33 cm³/cm³),抗剪强度最小为54 kPa。上红下...     

苹果类甜味蛋白编码基因Mdtl2克隆及功能的初步验证

植物类甜味蛋白(Thaumatin like proteins, TLPs)是一类具有抗菌活性和抗非生物胁迫作用的病程相关蛋白。本研究克隆获得富士苹果(Malus domestica cv. Fuji)TLPs家族蛋白Mdtl2编码基因，该基因开放阅读框全长为912 bp,编码303个氨基酸。生物信息学分析显示Mdtl2含有多个保守的半胱氨酸及TLPs家族保守序列片段，且具有TLPs典型的三维结构，属于TLPs家族的糖苷水解酶64家族(GH64-TLP-SF Superfamily)。在烟草中过表达Mdtl2能够显著抑制疫霉(Phytophthora infestans)的侵染。在苹果中过表达Mdtl2显著抑制苹果树腐烂病菌(Valsa mali)的侵染，并且能够诱导胼胝质的积累。上述结果表明，Mdtl2作为糖苷水解酶家族蛋白，能够通过诱导胼胝质的积累，提高植物对病原菌的抗性。