表面活性剂对加利利链霉菌AF1发酵的影响

【目的】研究表面活性剂对加利利链霉菌Streptomyces galilaeus AF1菌株发酵的影响。【方法】利用单因素试验优化表面活性剂的添加种类、初步浓度及最佳添加时间,采用Box-Behnken试验和响应面分析对表面活性剂添加质量浓度进行组合优化。流式细胞仪测定细胞荧光强度,确定表面活性剂对AF1菌株细胞膜的影响。【结果】表面活性剂的最优添加质量浓度:吐温–80为8.95 g·L~(–1)、曲拉通X–100为2.09 g·L~(–1)、山梨醇为3.89 g·L~(–1),最优添加时间为接种后5 d;细胞膜透性测定结果表明,试验组的AF1菌株细胞荧光强度极显著高于对照组。【结论】试验得到的响应面模型对因变量的解释程度达94.89%,具有实际意义;添加最优表面活性剂组合后,加利利链霉菌AF1的细胞膜通透性极显著增大,间接导致胞内活性物质的外排量增加,提高了抗菌活性物质的生物合成量。     

薄层扫描法测定人参降糖胶囊中AF的含量

采用薄层扫描法测定人参降糖胶囊中的精氨酸衍生物AF的含量。以正丁醇—冰醋酸—水(2∶1∶1)为展开剂,以2 g/L茚三酮乙醇溶液为显色剂,AF的测定波长λS=510 nm,参比波长λR=685 nm。测定结果表明:AF在1.00~3.50μg范围内线性关系良好,r=0.998 1。平均回收率99.77%(n=6),RSD=1.34%。     

The effect of heat treatment on the soluble protein content of oats

The effect of heat treatment on the soluble protein content in oat groats (Kerstin commercial variety) was evaluated using asymmetric flow field-flow fractionation (AF4) in combination with online multiangle light scattering (MALS) and UV detection. The AF4 method was used to separate the monomeric proteins from globulin hexamer and aggregate proteins and β-glucan polysaccharides in the soluble oat protein fraction. The total amount of soluble protein (with respect to total protein) was reduced to 35.7 ± 4.5 wt. % in heat treated oats from 74.6 ± 5.3 wt. % in non-heat treated oats. The ratio of monomeric to globulin hexamer and aggregate proteins was reduced from 1.82 to 1.48 as a result of heat treatment. Sodium-dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed the selective elimination of protein bands associated with the albumin and prolamin protein fractions as a result of heat treatment. These results were supported through amino acid analysis by cation exchange chromatography coupled with UV detection which revealed a reduction in amino acid residues associated with prolamin. The globulin proteins were found to be less sensitive to heat treatment.     

亚热带山地草地生态经济特性的研究

本文记载了亚热带山区不同海拔高度:(1)草地植物生物量的季节动态;(2)草群地上部现存量和生长量的逐月动态;(3)牧草的再生性;(4)草地抗土壤浸蚀的能力及对放牧的适应等。这些资料有利于山地草地的合理利用和正确决定草地的利用制度和方法,从而实现亚热带山地草地在适度利用的同时,保持其生态平衡。这项研究也从草地生态经济领域为亚热带山区的良性生态设计提供了基本依据。     

云南热区混农林系统的分类方法与分类系统研究

探讨混农林系统的分类方法和分类系统为混农林系统的评价与发展提供一个清晰而实用的框架。在云南热区现存在混农林系统模式全面清查的基础上，以目前国际公认的混农林高等级分类系统为基本轮廓，提出了云南热区混农林系统的亚系统单位（按不同分类目的确定），类型单位（组分构成方式和经营管理相同或相似）和模式单位（物种组成相同）三级结构分类系统，同时，按混农林系统生态区域和经营强度进行了区分。     

放线菌AF1代谢粗提物对无乳链球菌的抗菌活性

为了确定放线菌AF1代谢粗提物对无乳链球菌的抗菌效果,试验采用分光光度计和平板计数法确定菌株AF1代谢物对无乳链球菌的抗菌作用,并与几种常见无乳链球菌抗菌药物的效果进行比较。结果表明,放线菌AF1代谢粗提物对无乳链球菌有较强的抗菌作用,最小抑菌质量浓度(MIC)为38μg/mL,对无乳链球菌的杀菌作用表现出明显的时间剂量关系。扫描电镜结果表明作用后的无乳链球菌细胞壁严重破裂。静态法测得放线菌AF1代谢粗提物对斑马鱼的LC_(50)为27.44mg/L,拌饲喂食法测得LC_(50)为35.44mg/L,急性毒性表现为低毒。放线菌AF1代谢粗提物对无乳链球菌具有良好的抗菌活性,该研究可为无乳链球菌的防治提供新的线索。     

Effects of an immunomodulatory feed additive on body weight,production parameters,blood metabolites,and health in multiparous transition Holstein cows

The study investigated the impact of feeding OmniGen‐AF^® (OG; Phibro Animal Health, Quincy, IL) from dry‐off to week 4 of lactation at two doses on production performance and metabolic adaptation of multiparous Holstein cows. Forty‐eight cows were blocked and assigned randomly to three treatments: OG was fed at 0 g/head/day (CON), 60 g/head/day (OG60), or 90 g/head/day (OG90). No difference was observed in dry matter intake (DMI) throughout the experiment, whereas feeding OG tended to decrease the percentage body weight change (PWC) on week 2. Although colostrum yield was not affected by treatment, colostrum IgG production of OG90 tended to be higher than that of CON. OG supplementation did not affect overall milking performance but decreased milk SCC during the first 4 weeks of lactation. In prepartum, OG supplementation decreased the concentrations of serum albumin and calcium, and increased serum globulin. OG supplementation tended to increase serum total protein, globulin, and calcium contents postpartum. Furthermore, reduced incidence of mastitis and udder edema were observed. In conclusion, supplementing cows with OG from dry‐off period reduces or modulates the inflammation responses associated with parturition, potentially resulting in improved postpartum health, while feeding OG more than 60 g/head/day did not warrant further benefits.     

高压脉冲电场辅助提取人参中多种水溶物的工艺优化

【目的】优化高压脉冲电场辅助(PEF)法从人参药材中提取多种水溶物的工艺条件。【方法】以电场强度、脉冲数及料(g)液(mL)比为因变量,以人参皂苷、人参多糖、AF及AFG提取率为指标,在单因素试验基础上,设计3因素3水平正交试验,用PEF法提取人参中水溶性物质并对工艺参数进行优化,最后与用煎煮法和超声法对各提取物的提取率进行比较。【结果】用PEF法提取人参多种水溶物的最佳工艺条件为:电场强度25kV/cm,脉冲数10,料(g)液(mL)比1∶30。在此条件下,人参水提物中的皂苷、多糖、AF和AFG提取率分别为0.98%,7.20%,0.19%,0.11%;且各成分提取率均高于煎煮法及超声法。【结论】优化了人参中水溶物的提取工艺。     

Amylose and amylopectin in starch by asymmetric flow field-flow fractionation with multi-angle light scattering and refractive index detection (AF4–MALS–RI)

The rheological and functional properties of starch are influenced by the size and molar mass distribution of the polymer, the ratio of amylose (AMY) to amylopectin (AMP), and branching characteristics. Asymmetric Flow Field-Flow Fractionation (AF4) was applied to fractionate five different maize hybrids of varying AMY:AMP ratio. When coupled to detection by multi-angle light scattering and refractive index (MALS–RI), it was possible to determine mass percentage and the average weight-average molar mass (M_w) without the need for calibration standards. Sufficient resolution of amylose and amylopectin was achieved by applying a gradient cross-flow on a 17 cm trapezoidal channel with a 350 μm spacer. The observed M_w ranged from about 2 × 10⁵ to 4 × 10⁵ for amylose and from 1 × 10⁸ to 4 × 10⁸ for amylopectin. The corresponding z-average root-mean-square radii (R_z) for AMP ranged from 145 to over 300 nm. Low recoveries from the AF4 channel were found to be due primarily to the focusing step. The calculated mass percent of AMY and AMP from integrated RI peak areas agreed well with nominal values for the individual starch hybrids. Both qualitative and quantitative data were reproducible. The results show the AF4–MALS–RI method to be well suited for routine molecular characterization of starch.     

成都麻羊生态特征的研究

成都麻羊的生态特征和其生态条件紧密联系。麻羊产区,在海拔升高、生态条件改变的情况下,麻羊的某些生态特征亦发生相应的变化。如汶川县麻羊的体重、体高、体长、胸围、管围、胸深、胸宽等指标都高于大邑县麻羊,红血球、白血球、血红蛋白和血清钾的量亦较大邑县麻羊为高;汶川县麻羊被毛深厚,粗毛较稀,皮肤变厚,气管粗而长,环状软骨两端问距离大,心脏发育良好;汶川麻羊的消化系统除小肠外,均较大邑麻羊发达;甲状腺和肾上腺发育亦好。此外,成都麻羊的耐热性较差,汗腺属“顶浆分泌型”,但不能排汗。