Optimization of sulfated modification conditions of tremella polysaccharide and effects of modifiers on cellular infectivity of NDV

Based on our previous research, sulfated modification conditions of Tremella polysaccharide (TPS), the chlorosulfonic acid to pyridine (CSA-Pry) ratio, reaction temperature and time, were optimized by L₉ (3⁴) orthogonal design taking the yield and degree of sulfation (DS) of modifiers as indexes. Two TPSs, TPS_tp and TPS_70c, were modified under optimized conditions. The effects of two modifiers, sTPS_tp and sTPS_70c, on cellular infectivity of NDV were determined by MTT method taking the non-modified TPS_tp, TPS_tc and TPS_70c as controls. The results showed that the optimized modification conditions were reaction temperature of 80 °C, CSA-Pry ratio of 1:6 and reaction time of 1.5 h. Five polysaccharides at proper concentrations could significantly inhibit the infectivity of NDV to CEF. The virus inhibitory rates of sTPS_tp at 1.563 μg mL⁻¹ group were the highest and significantly higher than those of other three non-modified polysaccharide groups in three sample-adding modes. This indicated that sulfated modification could significantly improve the antiviral activity of TPS. sTPS_tp possessed the best efficacy and would be as a component of antiviral polysaccharide drug.     

马尾松幼胚体细胞胚胎发生研究

本论文首次报道了马尾松（Pinus massoniana Lamb.）幼胚体细胞胚胎发生的完整发育过程,并对影响马尾松胚性愈伤组织诱导的因素如球果采种期、球果冷藏处理时间、外植体处理方式等进行了探讨,统计胚性愈伤组织诱导率,进行增殖评价,探讨ABA浓度梯度对马尾松体细胞胚分化成熟的影响,试验数据用SPSS16统计分析软件进行方差分析、差异显著性检验。结果表明：1）2008~2009连续2年内15个采种期得到的幼胚,胚性愈伤组织诱导和增殖有显著性差异,最适宜的马尾松球果采种期是6月下旬至7月下旬,诱导率在9.66%~22.59%之间;2）球果冷藏处理时间,对胚性愈伤组织诱导有显著性差异,其中4℃冷藏球果15d有利于幼胚胚性愈伤组织诱导;3）雌配子体包含幼胚的接种处理方式是可取的;4）胚性愈伤组织经稳定增殖培养后,转入分化成熟培养基,得到体细胞胚状体＂爆发式＂分化成熟,数量多,质量好。适宜体胚成熟转化的培养基为：成熟LP培养基添加ABA5.0mg·L-1＋60.0g·L-1蔗糖,并附加L-谷氨酰胺和水解酪蛋白;5）成熟体细胞胚在无激素萌发型LP培养基上正常萌发,并转化为结构完整的小植株。本研究首次建立了马尾松幼胚体细胞胚胎发生技术平台,为马尾松遗传改良种质创新、缩短育种周期奠定了研究基础。     

Water relations in culture media influence maturation of avocado somatic embryos

Application of transformation and other biotechnological tools in avocado (Persea americana Mill.) is hampered by difficulties in obtaining mature somatic embryos capable of germination at an acceptable rate. In this work, we evaluated the effect of different compounds affecting medium water relations on maturation of avocado somatic embryos. Culture media were characterized with respect to gel strength, water potential and osmotic potential. Improved production of mature somatic embryos was achieved with gelling agent concentrations higher than those considered standard. The osmotic agents such as sorbitol and PEG did not have positive effects on embryo maturation. The number of w-o mature somatic embryos per culture was positively correlated with medium gel strength. Gel strength was significantly affected by gelling agent type as well as by gelling agent and PEG concentration. Medium water potential was influenced by sorbitol concentration; incorporation of PEG to a culture medium did not affect medium water potential. The highest maturation results were achieved on a medium gelled with 10 g l⁻¹ agar. Moreover, these somatic embryos had improved germination rates. These results corroborate the role of water restriction as a key factor controlling maturation of somatic embryos.     

A-FABP基因多态性与肉鸡生长和体组成性状的关联

为探讨A-FABP基因多态性对肉鸡生长和体组成性状的影响,文章选用肉鸡高、低脂双向选择品系第十世代肉仔鸡为实验材料,采用测序、PCR-RFLP、PCR-LP、DHPLC方法进行基因多态性检测和个体基因型分析,通过对8个SNPs进行连锁不平衡分析并选择5个标签SNPs构建单倍型,进而利用单位点和单倍型分别与鸡生长和体组成性状进行关联分析。结果表明,7个SNPs(除SNP 5以外)及单倍型同时对鸡肌胃重、肌胃率有显著影响(P<0.05),而对生长和其他体组成性状无显著影响(P>0.05)。鉴于不同物种A-FABP基因现有的功能研究均没有发现其对消化系统有重要作用,因此该基因是否为影响肉鸡肌胃重和肌胃率的主效基因还有待于进一步研究。     

Brood parasitism is associated with increased bacterial contamination of host eggs: bacterial loads of host and parasitic eggs

Factors related to bacterial environment of nests are of primary interest for understanding the causes of embryo infection and the evolution of antimicrobial defensive traits in birds. Nest visitors such as parasites could act as vectors for bacteria and/or affect the hygienic conditions of nests and hence influence the nest bacterial environment. In the present study, we explored some predictions of this hypothetical scenario in the great spotted cuckoo (Clamator glandarius)–magpie (Pica pica) system of brood parasitism. Great spotted cuckoos visit the nests of their magpie hosts and frequently damage some of the host eggs when laying eggs or on subsequent visits. Therefore, it represents a good system for testing the effect of nest visitors on the bacterial environment of nests. In accordance with this hypothesis, we found that the bacterial load of magpie eggshells was greater in parasitized nests, which may suggest that brood parasitism increases the probability of bacterial infection of magpie eggs. Moreover, comparisons of bacterial loads of cuckoo and magpie eggs revealed that: (1) cuckoo eggshells harboured lower bacterial densities than those of their magpie hosts in the same nests and (2) the prevalence of bacteria inside unhatched eggs was higher for magpies than for great spotted cuckoos. These interspecific differences were predicted because brood parasitic eggs (but not host eggs) always experience the bacterial environments of parasitized nests. Therefore, the results obtained in the present study suggest that parasitic eggs are better adapted to environments with a high risk of bacterial contamination than those of their magpie hosts. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 836–848.     

鸡源CD40L基因克隆、蛋白表达及生物活性检测

为获得鸡源CD40L (chCD40L) 蛋白,以鸡脾细胞制备cDNA并以之为模板扩增chCD40L基因,构建pFastBac-chCD40L供体重组质粒,转化感受态细胞DH10Bac,通过筛选及鉴定获得Bacmid-chCD40L重组质粒,转入真核表达系统sf9昆虫细胞进行蛋白表达与纯化,获得His-chCD40L蛋白。此外,构建pQM01-chCD40L质粒,转染HEK 293T细胞进行蛋白表达与纯化,获得Strep-chCD40L蛋白。亲和层析纯化的chCD40L蛋白浓度为0.01 mg/mL。为检测chCD40L蛋白的生物活性,分离和培养3周龄SPF雏鸡的法氏囊组织原代细胞,将chCD40L加入细胞培养液刺激细胞增殖,通过Western blotting试验、间接免疫荧光试验、流式细胞术检测,发现该蛋白能够与法氏囊B淋巴细胞表面的CD40结合,说明chCD40L具有生物活性。成功获得chCD40L蛋白,为原代B淋巴细胞体外培养及IBDV野毒分离与诊断奠定了基础。     

Oleate promotes differentiation of chicken primary preadipocytes in?vitro

In addition to providing energy and constituting cell membrane, fatty acids also play an important role in adipocyte differentiation and lipid metabolism. As an important member of monounsaturated fatty acids, oleate, together with other components, is widely used to induce chicken preadipocyte differentiation. However, it is not clear whether oleate alone can induce chicken preadipocyte differentiation. In the present study, four different treatments were designed to test this question: basal medium, IDX [insulin, dexamethasone and IBMX (isobutylmethylxanthine)], oleate and IDX plus oleate. Cytoplasmic lipid droplet accumulation and mRNA expression for adipogenesis-related genes were monitored. After treatment of oleate on chicken preadipocytes, apparent lipid droplet formation and lipid accumulation were observed, accompanied by increasing expression of PPARγ (peroxisome proliferator-activated receptor-γ) and AFABP (adipocyte fatty acid-binding protein), but decreasing level of GATA2 (GATA-binding protein 2). In contrast, for cells cultured in the basal medium with or without IDX supplementation, lipid droplet barely occurred. These results suggest that exogenous oleate alone can act as an inducer of preadipocyte differentiation into adipocytes.     

Molecular cloning,expression and characterization of Pekin duck interferon-λ

Interferons (IFNs) are the first line of defense against viral infections in vertebrates. Type III interferon (IFN-λ) is recognized for its key role in innate immunity of tissues of epithelial origin. Here we describe the identification of the Pekin duck IFN-λ ortholog (duIFN-λ). The predicted duIFN-λ protein has an amino acid identity of 63%, 38%, 37% and 33% with chicken IFN-λ and human IFN-λ3, IFN-λ2 and IFN-λ1, respectively. The duck genome contains a single IFN-λ gene that is comprised of five exons and four introns. Recombinant duIFN-λ up-regulated OASL and Mx-1 mRNA in primary duck hepatocytes. Our observations suggest evolutionary conservation of genomic organization and structural features implicated in receptor binding and antiviral activity. The identification and expression of duIFN-λ will facilitate further study of the role of type III IFN in antiviral defense and inflammatory responses of the Pekin duck, a non-mammalian vertebrate and pathogen host with relevance for human and animal health.