两相系统在疏水性有机污染物高效降解菌富集培养中的应用研究进展

环境中疏水性有机污染物(Hydrophobic organic pollutants,HOPs)的浓度日益增加,获取HOPs高效降解功能微生物能有效提高HOPs污染治理效率。近年来,利用两相系统促进HOPs微生物降解转化的研究已取得一定进展。本文重点从两相系统的结构特点及其富集HOPs降解功能微生物的原理、主要影响因素和应用情况等方面进行综述,并在此基础上对两相系统在毒害性HOPs微生物加速降解脱毒中所存在的主要问题及其应用前景进行讨论和展望。     

固定化微生物在生物膜式生化需氧量传感器中的应用现状

生化需氧量(Biochemical oxygen demand,BOD)微生物传感器是一种快速检测水样中有机污染物含量的设备,固定化微生物是其核心部件之一,对其稳定性、响应时间、使用寿命及实际应用范围等性能有着重要影响。生物膜式BOD传感器较其他类型的BOD微生物传感器具有结构简单、灵敏度高、响应时间短等优点,受到广泛的研究和应用。本文主要针对固定化微生物在生物膜式BOD传感器中的应用情况,概述较典型的微生物固定化方式的原理、特点及应用;总结几类应用较多或具有较好前景的载体材料,并讨论载体特性与传感器性能之间的关系;综述微生物在该领域的应用现状;简要介绍生物膜式BOD传感器的实际应用及商业化现状,比较其与另外几种BOD微生物传感器的优缺点;分析生物膜式BOD传感器中固定化微生物现存的一些问题及其发展趋势。     

泸型酒酒醅中梭菌群落的发酵演替规律和功能预测

【目的】研究泸型酒酒醅中梭菌(Clostridia)群落的演替规律,探讨梭菌群落在酒醅发酵过程中的潜在功能。【方法】利用实时荧光定量PCR技术结合高通量测序技术研究不同发酵时间泸型酒酒醅中梭菌丰度变化;通过梭菌16S r RNA基因序列高通量测序数据分析揭示梭菌群落演替规律,并运用LEf Se分析找出标志性OTU;通过PICRUSt分析对梭菌功能组成进行预测。【结果】泸型酒发酵过程酒醅中梭菌的生物量在发酵14 d上升至最高(3.46×10~7 copies/g),梭菌占总细菌的相对丰度在发酵20 d达到最高(6.67%);对梭菌群落结构的聚类分析结果表明,发酵7 d的酒醅梭菌群落结构显著区别于其他发酵时间,主要体现为存在17个标志性OTU,其中大部分分类学地位尚不明确;PICRUSt分析显示梭菌主要参与氨糖与核糖代谢、磷酸戊糖途径,其次是果糖和甘露糖代谢、TCA循环、糖酵解途径、丙酸及丁酸代谢。【结论】泸型酒酒醅中梭菌的生物量和占细菌的相对丰度在发酵开始后的2-3周内逐渐达到最高,而梭菌群落的结构则在发酵1周内便发生了显著改变,并在发酵2-3周内趋于稳定。在发酵2-3周时有较多与丙酸、丁酸等风味物质代谢相关的基因在酒醅梭菌中被预测到。     

小麦赤霉病原菌拮抗菌Bacillus amyloliquefaciens 7M1产抗菌素的研究

【目的】从小麦根际土壤分离鉴定一株赤霉病拮抗菌,对该菌产的抗菌素进行生物学性质研究、种类鉴定和抑菌实验。【方法】利用牛津杯法和光照培养箱实验对其抑菌活性进行测定,通过16S r RNA基因序列分析对目标菌株的种属进行初步鉴定,根据抗菌素相关基因进行PCR扩增和测序,利用在线软件Pro Param tool和TMHMM对编码蛋白进行生物信息学分析。【结果】7M1菌体和抗菌素对禾谷镰刀菌的抑菌圈直径分别为16.33±0.13 mm和15.43±0.21 mm,16S r RNA基因序列分析结果显示其为芽孢杆菌,并与解淀粉芽孢杆菌具有较近的亲缘关系,菌株7M1抗菌素对小麦赤霉病的温室防治效果为76.41%,而且热稳定性好,可被蛋白酶K、胰蛋白酶、胃蛋白酶降解,在p H 5.0-10.0有较好的抑菌活性,但是紫外线辐射会降低其抑菌活性。菌株7M1含有bac AB、itu C、bam D 3种基因,通过与Gen Bank中相关的抗菌素基因进行比对,发现其编码的氨基酸序列与Gen Bank库中的芽孢杆菌溶素、伊枯草菌素和杆菌抗霉素D等抗菌素的相似性达到99%。bac AB编码蛋白和itu C编码蛋白是稳定蛋白,bam D编码蛋白是不稳定蛋白,此外,3种基因的编码产物不具有明显的跨膜结构。【结论】从该菌发酵液提取的抗菌素有很好的抗禾谷镰刀菌活性而且性质稳定,因而在小麦赤霉病的生物防治中具有潜在的应用价值。     

细菌sRNA与群体感应系统相互作用研究进展

细菌s RNA是一类长度在40-500 nt之间的非编码RNA,在细菌细胞感应外界环境压力变化、控制基因表达方面发挥着重要的作用。本文综述了细菌s RNA与群体感应系统相互作用在调控基因表达方面的研究进展,对揭示细菌错综复杂的代谢调控过程,以及了解细菌对外界环境变化的响应机制具有十分重要的意义。     

干旱复水对海棠叶片光合蒸腾及水分利用效率的影响

以13个类型的盆栽海棠为材料,分析了自然干旱及旱后复水时叶片净光合速率(net photosynthesis rate,Pn),蒸腾速率(transpiration rate,Tr)及水分利用效率(water use effi ciency,WUE)。结果表明:13个海棠中,西府海棠的Pn和WUE最低,对水分变化最不敏感;平邑甜茶比较适应轻度和中度干旱,不适应重度干旱。复水后‘紫色王子’、‘绚丽’和‘雪球’等9个类型的Pn明显超过原初状态;‘红艳’、‘糖美林’、‘红粉’、‘红宝石’和‘王族’通过提高WUE来抵抗干旱胁迫,‘绚丽’、‘红丽’和垂丝海棠通过维持较强的恢复能力适应抗旱。干旱时,‘绚丽’比其他海棠能够更高效地利用水分。     

FUNDC1 regulates mitochondrial dynamics at the ER–mitochondrial contact site under hypoxic conditions

In hypoxic cells, dysfunctional mitochondria are selectively removed by a specialized autophagic process called mitophagy. The ER–mitochondrial contact site (MAM) is essential for fission of mitochondria prior to engulfment, and the outer mitochondrial membrane protein FUNDC1 interacts with LC3 to recruit autophagosomes, but the mechanisms integrating these processes are poorly understood. Here, we describe a new pathway mediating mitochondrial fission and subsequent mitophagy under hypoxic conditions. FUNDC1 accumulates at the MAM by associating with the ER membrane protein calnexin. As mitophagy proceeds, FUNDC1/calnexin association attenuates and the exposed cytosolic loop of FUNDC1 interacts with DRP1 instead. DRP1 is thereby recruited to the MAM, and mitochondrial fission then occurs. Knockdown of FUNDC1, DRP1, or calnexin prevents fission and mitophagy under hypoxic conditions. Thus, FUNDC1 integrates mitochondrial fission and mitophagy at the interface of the MAM by working in concert with DRP1 and calnexin under hypoxic conditions in mammalian cells.     

CYP2J2 and its metabolites (epoxyeicosatrienoic acids) attenuate cardiac hypertrophy by activating AMPKα2 and enhancing nuclear translocation of Akt1

Cytochrome P450 epoyxgenase 2J2 and epoxyeicosatrienoic acids (EETs) are known to protect against cardiac hypertrophy and heart failure, which involve the activation of 5′‐AMP‐activated protein kinase (AMPK) and Akt. Although the functional roles of AMPK and Akt are well established, the significance of cross talk between them in the development of cardiac hypertrophy and antihypertrophy of CYP2J2 and EETs remains unclear. We investigated whether CYP2J2 and its metabolites EETs protected against cardiac hypertrophy by activating AMPKα2 and Akt1. Moreover, we tested whether EETs enhanced cross talk between AMPKα2 and phosphorylated Akt1 (p‐Akt1), and stimulated nuclear translocation of p‐Akt1, to exert their antihypertrophic effects. AMPKα2^?/? mice that overexpressed CYP2J2 in heart were treated with Ang II for 2 weeks. Interestingly, overexpression of CYP2J2 suppressed cardiac hypertrophy and increased levels of atrial natriuretic peptide (ANP) in the heart tissue and plasma of wild‐type mice but not AMPKα2^?/? mice. The CYP2J2 metabolites, 11,12‐EET, activated AMPKα2 to induce nuclear translocation of p‐Akt1 selectively, which increased the production of ANP and therefore inhibited the development of cardiac hypertrophy. Furthermore, by co‐immunoprecipitation analysis, we found that AMPKα2β2γ1 and p‐Akt1 interact through the direct binding of the AMPKγ1 subunit to the Akt1 protein kinase domain. This interaction was enhanced by 11,12‐EET. Our studies reveal a novel mechanism in which CYP2J2 and EETs enhanced Akt1 nuclear translocation through interaction with AMPKα2β2γ1 and protect against cardiac hypertrophy and suggest that overexpression of CYP2J2 might have clinical potential to suppress cardiac hypertrophy and heart failure.     

Synthesis and Bioactivity of Novel Trisubstituted Triazole Nucleosides

A series of novel trisubstituted 1,2,3-triazole purine nucleosides were efficiently synthesized via Huisgen 1,3-dipolar cycloaddition in good yields. Bioactivity against cytomegalovirus (CMV) and varicella-zoster virus (VZV) in human embryonic lung cell cultures was evaluated and all compounds show low antiviral activity.