Investigation of Interspecies Interactions within Marine Micromonosporaceae Using an Improved Co-Culture Approach

With respect to bacterial natural products, a significant outcome of the genomic era was that the biosynthetic potential in many microorganisms surpassed the number of compounds isolated under standard laboratory growth conditions, particularly among certain members in the phylum Actinobacteria. Our group, as well as others, investigated interspecies interactions, via co-culture, as a technique to coax bacteria to produce novel natural products. While co-culture provides new opportunities, challenges exist and questions surrounding these methods remain unanswered. In marine bacteria, for example, how prevalent are interspecies interactions and how commonly do interactions result in novel natural products? In an attempt to begin to answer basic questions surrounding co-culture of marine microorganisms, we have tested both antibiotic activity-based and LC/MS-based methods to evaluate Micromonosporaceae secondary metabolite production in co-culture. Overall, our investigation of 65 Micromonosporaceae led to the identification of 12 Micromonosporaceae across three genera that produced unique metabolites in co-culture. Our results suggest that interspecies interactions were prevalent between marine Micromonosporaceae and marine mycolic acid-containing bacteria. Furthermore, our approach highlights a sensitive and rapid method for investigating interspecies interactions in search of novel antibiotics, secondary metabolites, and genes.     

Grow-out of sandfish Holothuria scabra in ponds shows that co-culture with shrimp Litopenaeus stylirostris is not viable

We examined the potential for producing the large numbers of sandfish (Holothuria scabra) needed for restocking programmes by co-culturing juveniles with the shrimp Litopenaeus stylirostris in earthen ponds. Our experiments in hapas within shrimp ponds were designed to detect any deleterious effects of sandfish on shrimp, and vice versa. These experiments showed that a high stocking density of juvenile sandfish had no significant effects on growth and survival of shrimp. However, survival and growth of sandfish reared with shrimp for 3 weeks were significantly lower than for sandfish reared alone. Increased stocking density of shrimp also had a significant negative effect on survival and/or growth of sandfish. A grow-out trial of juvenile sandfish in 0.2-ha earthen ponds stocked with 20 shrimp post-larvae m^− 2, and densities of sandfish between 0.8 and 1.6 individuals m^− 2, confirmed that co-culture is not viable. All sandfish reared in co-culture were dead or moribund after a month. However, sandfish stocked alone into 0.2-ha earthen ponds survived well and grew to mean weights of ∼ 400 g within 12 months without addition of food. The grow-out trial demonstrated that there is potential for profitable pond farming of sandfish in monoculture. Further research is now needed to identify the optimal size of juveniles, stocking densities and pond management regimes.     

混合培养体系对实际染料废水的脱色与降解研究

[目的]研究混合培养体系对染料废水的脱色和降解务件,为印染工业废水的大规模生物处理奠定基础。[方法]利用4株丝状真菌和4株细菌组建一真菌细茵混合培养体系,考察了该混合培养体系在不同条件下对2种染料废水的脱色与降解效果。[结果]2种废水在中和预处理使pH在6．0左右后,真菌与细菌以2：1同时接种效果较好,通氧有利于脱色与降解,处理时间因水质而异。对深蓝废水12h脱色率和降解率分别达到98．36％和92．70％;对难于脱色的中红废水24h脱色率和降解率分别达到87．22％和82．98％。通过全波长扫描图谱,证明了大部分染料被降解。[结论]通过研究确定了该混合培养体系对染料废水脱色和降解的最佳条件。     

发生培养基中添加孕酮对牛体外受精卵发育的影响

通过在发生培养液中添加孕酮以研究外源性孕酮对牛体外受精卵发育的影响。结果表明,适量添加孕酮有助于胚胎的体外发育。其中,10ng/ml孕酮添加组的8细胞胚胎发生率(55％)极显著高于对照组(39.0％)(P<0.01);囊胚发生率(18.9％)亦显著高于对照组(9.6％)(P<0.05)。但这种促进作用是通过混合培养系统中的颗粒膜细胞得以实现的。本试验未发现孕酮对胚胎是否产生直接作用。     

不同饲养层对兔原始生殖细胞传代培养的影响

为了探讨不同饲养层细胞对兔原始生殖细胞体外培养与传代的影响,从14~18 d的兔胎儿生殖嵴中分离得到原始生殖细胞(PGCs),分别培养在小鼠胎儿成纤维细胞(MEF)、兔胎儿成纤维细胞(REF)饲养层上或与同源兔胎儿生殖脊成纤维细胞(HEFgr)、兔睾丸支持细胞(RSC)共培养。观察兔类EG集落的生长状态,并检测其碱性磷酸酶活性。结果表明:4种方法均能分离克隆出兔类EG集落,碱性磷酸酶染色均呈阳性,但是采用共培养的模式分离得到的集落明显多于传统的饲养层模式。与RSCs共培养得到的EG集落数最多,保持未分化的时间最长,并传了8代,与HEFgr共培养得到的EG集落数与RSCs相比差异不明显,但最高只传了6代。培养在MEF上的兔类EG也能较好的保持未分化状态,传了4代。培养在REF上的兔类EG集落数目较少,出现分化时间较早,只传了3代。因此可以用与RSCs或HEFgr共培养的方法传代培养兔PGCs。     

少根紫萍对湿地污染水体的修复研究

大量含氮、磷的污水未经处理直接排放到当地河流湖泊等自然水体中,导致湿地环境越来越恶劣,水体富营养化程度加剧,对污染水体的修复已迫在眉睫。本实验以1/5的Hoagland溶液为培养液,设置0 mL·L^-1、20 mL·L^-1、40 mL·L^-1、80 mL·L^-1、160 mL·L^-1五个铜绿微囊藻接种浓度梯度与0 mg·m^-2、100 mg·m^-2、200 mg·m^-2、400 mg·m^-2、800 mg·m^-2 5个少根紫萍接种浓度梯度进行双因素正交试验。结果发现,在0~15 d内,所有少根紫萍接种浓度和铜绿微囊藻接种浓度处理下,水体中总氮(TN)、磷(TP)含量随着接种时间的增加而降低,且铜绿微囊藻和少根紫萍共培养比各自单独培养对污染水体具有更好的修复效果。15d后测定培养液中藻毒素和少根紫萍体内藻毒素含量,结果表明少根紫萍可有效吸收培养液中的藻毒素。以上结果表明,低浓度铜绿微囊藻可促进少根紫萍生长,高浓度铜绿微囊藻抑制少根紫萍生长,少根紫萍可有效吸收培养液中的TN、TP和藻毒素。在铜绿微囊藻浓度为20 mL·L^-1、少根紫萍接种浓度为400 mg·m^-2时,浮萍生长状况最好,对培养液中TN、TP及藻毒素的去除率也达到最高。综上所述,低浓度铜绿微囊藻和100%覆盖率的少根紫萍共培养用于湿地水体修复具有良好的修复效果。     

共培养体系对哺乳动物卵母细胞体外成熟影响的研究进展

卵母细胞体外成熟是进行体外胚胎生产的关键环节,但目前哺乳动物卵母细胞体外成熟培养存在成熟率低、受精率低和胚胎质量差等问题。卵母细胞体外成熟培养体系是制约卵母细胞体外成熟效果的重要因素,共培养体系可提高哺乳动物卵母细胞体外成熟效率。本文主要从卵母细胞成熟与卵泡细胞共培养、与裸卵共培养和与间充质干细胞共培养3个方面综述共培养体系对哺乳动物卵母细胞体外成熟的影响,为共培养体系应用于卵母细胞体外成熟提供理论依据和研究借鉴。     

山羊转基因克隆胚在体内和体外发育的研究

探讨了体内/外成熟卵母细胞、体内/外培养系统、输卵管液和输卵管上皮细胞共培养系统对转基因克隆胚发育的影响。结果表明:体内/外成熟卵母细胞对转基因克隆胚各阶段发育率无显著影响。体内/外培养系统中,转基因克隆胚2～3-细胞、4-细胞、8-细胞发育率差异不显著;16-细胞和桑/囊胚发育率差异显著。对照组和20%输卵管液中,转基因克隆胚2～3-细胞、4-细胞、8-细胞发育率均显著高于50%输卵管液;在20%输卵管液中16-细胞的发育率显著高于对照组和50%输卵管液。转基因克隆胚在输卵管上皮细胞共培养系统和SOF培养系统中培养,2～3-细胞和4-细胞发育率无显著差异;8-细胞、16-细胞和桑/囊胚的发育率差异显著。     

小鼠孤雌胚胎体外共培养体系的建立

[目的]在输卵管上皮细胞和/或垂体细胞饲养层下培养小鼠孤雌胚胎,探讨促进小鼠孤雌胚发育突破2-cell阻滞的机制,建立完善的培养体系。[方法]复式激活小鼠卵母细胞后分别在不同饲养层的CZB培养液中进行培养,并观察、比较各培养条件下孤雌胚胎的发育情况。[结果]培养至24 h,各组无显著差异,都有较高卵裂率。培养至48 h,2类饲养层细胞下的孤雌胚胎48-cell发育效果好,与单独一类饲养层细胞培养差异显著,与对照组比较差异极显著。培养至96 h,2类饲养层细胞下有49.4%（42/85）孤雌胚胎发育为桑囊胚,与其他各组比较差异极显著。[结论]含有输卵管上皮细胞＋垂体细胞的CZB培养液可有效促进小鼠孤雌胚胎发育突破2-cell阻滞,并进一步提高其发育率。     

内生真菌产植物次生代谢产物研究进展

概述了宿主植物与内生真菌的关系,总结了内生真菌次生代谢产物结构及生物活性多样性,重点分析了内生真菌规模化生产高价值植物次生代谢产物存在的问题及解决策略,并展望了未来发展方向。