Deacylation of Calcium-Dependent Antibiotics from Streptomyces violaceoruber in Co-culture with Streptomyces sp. MG7-G1

When Streptomyces violaceoruber grows together with Streptomyces sp. MG7-G1, it reacts with strongly induced droplet production on its aerial mycelium. Initially the metabolite profile of droplets from S. violaceoruber in co-culture with Streptomyces sp. MG7-G1 was compared to samples from S. violaceoruber in single-culture by using high-performance liquid chromatography-mass spectrometry (HPLC-MS). Then, the exudate from agar plates of co-cultures and single cultures (after freezing and thawing) was also analysed. Several compounds were only observed when S. violaceoruber was grown in co-culture. Based on their high-resolution ESI mass spectra and their comparable retention times to the calcium-dependent antibiotics (CDAs) produced by S. violaceoruber, the new compounds were suspected to be deacylated calcium-dependent antibiotics (daCDAs), lacking the 2,3-epoxyhexanoyl residue of CDAs. This was verified by detailed analysis of the MS/MS spectra of the daCDAs in comparison to the CDAs. The major CDA compounds present in calcium ion-supplemented agar medium of co-cultures were daCDAs, thus suggesting that Streptomyces sp. MG7-G1 expresses a deacylase that degrades CDAs.     

江汉盆地潜江凹陷古近系潜江组白云岩成因

潜江凹陷位于江汉盆地，其古近系潜江组以含有由富有机质白云岩和蒸发岩组成的193个韵律层为特征。然而，潜江凹陷古近系潜江组白云石的成因一直存在争议，限制了进一步对非常规油气的勘探工作。根据盐间层岩相与矿物特征研究潜江组盐间层富白云石岩相的沉积成因。根据沉积特征观测（岩心和薄片）和矿物组分数据，可识别出3种主要的岩相结合：薄层-纹层状泥晶白云岩、纹层状含云泥晶灰岩和夹钙芒硝层状泥晶白云岩。研究发现前两种岩相组合纹层特征明显，可见有机质纹层与无机纹层交互现象，说明形成于水体较深的还原环境。白云石与方解石晶体含有有机质降解孔，且白云石与黄铁矿和有机质薄膜共生，说明其成因与微生物诱导活动有关。浮游微生物和底栖藻分别控制了方解石和白云石的沉淀。这些岩相组合含有较高的有机质含量。最后一种岩相组合具有较高的蒸发矿物含量和陆源碎屑物质，说明其形成于相对浅水环境。高盐度和强烈陆源输入不利于有机质的保存。此次研究发现盐湖内白云石的形成受微生物活动和蒸发环境控制，不同的成因对岩相沉积特征和有机质富集产生重要影响。     

金属离子对活性污泥微生物影响研究进展

介绍了金属离子对活性污泥微生物的影响,对其影响的机理进行了研究,结合国内外有关金属离子对活性污泥影响的研究成果,提出通过研究投加金属离子而提高污水处理效果成为目前的研究热点。     

LNG接收站次氯酸钠投加量确定及产生装置选择

LNG接收站通常采用海水作为气化LNG的热媒,但实际运行中,却存在海洋微生物滋生、附着管道及设备的风险。因此,LNG接收站通常会在海水取水口处投加次氯酸钠(NaClO),但NaClO投加量及产生装置却是其必须考虑的问题。首先,分析了投加量的影响因素及评价标准,并以大连LNG接收站为例说明投加量的具体确定方法;其次,分析了电解海水制NaClO装置及NaClO溶液直接投加装置,并计算了二者的运行成本;最后,就两种装置的优劣进行对比分析。结果显示,电解海水制NaClO装置具有运行成本低、NaClO即产即用的优点;而NaClO溶液直接投加装置则具有前期投资费用低、装置简单和建造面积小的优点。     

微生物水泥研究与应用进展

微生物诱导碳酸钙沉积(MICP),即利用微生物代谢活动中矿化行为,诱导形成碳酸钙沉淀,其具有特殊的胶结作用,可作为一种新颖的生物胶凝材料—微生物水泥。本文从MICP矿化机制、胶结机理以及微生物水泥在岩土工程中的应用等方面探讨了相应的最新进展,分析了目前存在的问题,并对微生物水泥的进一步研究提出了思路和建议。     

浅谈防疫用移动方舱开发制造与检测验证现状

防疫用移动方舱从原理和功能上属于受控洁净空间,目前没有专用制造标准与验证方法,一般沿用固定洁净室的制造测试方法。然而方舱在搭建、验证和使用过程中面临许多与固定式洁净室不同的细节问题,这主要源于方舱有限的空间条件,同时要兼顾成本、移动性和可靠性等。因此,基于已有相关技术标准与实际建造使用情况,对于方舱的专门制造标准和测试方法的讨论已经成为业内下一步工作的重要议题,以期对其有更有效合理的建造指导与质量管理,助力形成真正意义上的应急空间储备与快速投入使用的能力。     

Chemically Synthesized 58‐mer LysM Domain Binds Lipochitin Oligosaccharide

Recognition of carbohydrates by proteins is a ubiquitous biochemical process. In legume–rhizobium symbiosis, lipochitin oligosaccharides, also referred to as nodulation (nod) factors, function as primary rhizobial signal molecules to trigger root nodule development. Perception of these signal molecules is receptor mediated, and nod factor receptor 5 (NFR5) from the model legume Lotus japonicus is predicted to contain three LysM domain binding sites. Here we studied the interactions between nod factor and each of the three NFR5 LysM domains, which were chemically synthesized. LysM domain variants (up to 58 amino acids) designed to optimize solubility were chemically assembled by solid‐phase peptide synthesis (SPPS) with microwave heating. Their interaction with nod factors and chitin oligosaccharides was studied by isothermal titration calorimetry and circular dichroism (CD) spectroscopy. LysM2 showed a change in folding upon nod factor binding, thus providing direct evidence that the LysM domain of NFR5 recognizes lipochitin oligosaccharides. These results clearly show that the L. japonicus LysM2 domain binds to the nod factor from Mesorhizobium loti, thereby causing a conformational change in the LysM2 domain. The preferential affinity for nod factors over chitin oligosaccharides was demonstrated by a newly developed glycan microarray. Besides the biological implications, our approach shows that carbohydrate binding to a small protein domain can be detected by CD spectroscopy.     

大曲微生物在大曲酒生产中的研究开发现状及发展前景

概述了大曲微生物的类型及研究开发与应用现状,并对其发展前景进行展望,旨在为大曲微生物的研究提供思路,进一步从微生物的角度揭示中国白酒的发酵本质.     

生物药剂在矿物加工和冶金中的应用

综述了生物药剂在矿的加工和冶金中的研究现状及应用，指出了生物药剂的发展趋势及研究方向。     

微生物浸矿技术在选铜工业中的应用

简单介绍了微生物在选铜工业中浸矿技术的概念以及在国内外的发展概况，总结了浸矿微生物的种类以及微生物在浸矿过程中的直接作用和间接作用，为我国矿床研究、低品位和难选矿石的选冶提供了新的技术开发利用途径。