家蝇抗菌肽AMP-17对白色念珠菌菌丝的抑制作用

【背景】AMP-17是从微生物诱导的家蝇转录组数据库筛选到的一条特异性高表达基因,采用原核表达体系获得其重组蛋白并证实了具有显著的抗菌效果,特别是对白色念珠菌具有较强的抗菌活性。【目的】研究抗菌肽AMP-17对白色念珠菌菌丝的抑制作用。【方法】采用微量液体稀释法测定AMP-17对11株白色念珠菌的最小抑菌浓度(minimal inhibitory concentration,MIC);根据对AMP-17的敏感程度选取3株绘制生长曲线;通过光学显微镜观察并计数经AMP-17作用后白色念珠菌芽生孢子生成率及芽管形成率;倒置荧光显微镜观察白色念珠菌酵母相向菌丝相转化及以菌丝相为起点AMP-17促进菌丝相转化为酵母相的情况。【结果】AMP-17对支气管肺泡灌洗液分离株16105的MIC为10μg/mL,对粪便分离株16214的MIC为40μg/mL,对其余9株白色念珠菌的MIC均为20μg/mL;白色念珠菌经不同浓度的AMP-17作用后,各时间点的芽生孢子生成率均显著低于对照组,尤其是40μg/mL的AMP-17组,芽生孢子生成率仅15%,显著低于阳性药物氟康唑;各实验组芽管形成率显著低于对照...     

白背叶种仁油的提取及成分分析

采用超临界CO2流体萃取技术(SFE-CO2)提取了采集于湖南省凤凰县、泸溪县、古丈县和吉首市的白背叶种子的种仁油,种仁油甲酯化后,运用气相色谱—质谱联用技术(GC-MS)测定其化学成分。结果表明,四个采样点的白背叶种仁油共同含有油酸、棕榈酸、亚油酸、硬脂酸和杜鹃花酸,它们的相对含量依次减少。其中前四种为白背叶种仁油的主要组成成分,它们的总和在种仁油中所占的比例是凤凰98.92%、古丈96.67%、吉首94.84%、泸溪94.58%。     

Marc-145细胞无血清培养液组分的优化筛选

目的：对Marc-145细胞无血清培养液组分及浓度进行优化筛选。方法：采用Plackett-Burman设计和中心组合旋转设计对不同的营养成分进行优化筛选。结果：经Plackett-Burman设计,利用20组实验对14种不同营养成分进行考察,发现孕酮、抗氧化试剂、乙醇胺、维生素B12、维生素B12和脂肪酸复合剂对Marc-145细胞无血清悬浮生长的比生长速率有显著影响;针对该6种因素进行中心组合旋转实验设计,利用53组实验筛选出它们的最优使用浓度分别为孕酮5．5mg／L、抗氧化试剂250μL/L、乙醇胺2．1mL／L、维生素B12 2．86mg／L、维生素B6 44μg/L和脂肪酸复合剂215μL/L。结论：经2种实验设计方法优化,确定了Marc-145细胞无血清培养液组分及最适浓度,为无血清悬浮培养Marc-145细胞及增殖猪繁殖及呼吸综合征病毒提供了实验基础。     

药用拟层孔菌石油醚提取物的GC-MS分析及各相提取物生物活性

通过形态学和分子生物学分析,实验菌株为药用拟层孔菌。采用不同有机溶剂提取药用拟层孔菌子实体,分别获得石油醚、氯仿、乙酸乙酯和甲醇提取物。采用GC-MS方法,分析药用拟层孔菌石油醚提取物中的化学成分,同时对不同有机溶剂提取物的生物活性进行检测。结果表明:药用拟层孔菌石油醚提取物中共鉴定出46个化合物。体外抑制肿瘤细胞活性实验表明,在100μg/m L时,不同有机溶剂提取物都表现出抑制肿瘤细胞活性。其中,石油醚提取物在50μg/m L时,其对NCI-H460和SGC-7901肿瘤细胞的抑制率分别为99.03%和82.57%。甲醇提取物在8mg/m L时,DPPH自由基清除率达93.35%。     

Rare taxa maintain the stability of crop mycobiomes and ecosystem functions

Plants harbour highly diverse mycobiomes which sustain essential functions for host health and productivity. However, ecological processes that govern the plant–mycobiome assembly, interactions and their impact on ecosystem functions remain poorly known. Here we characterized the ecological role and community assembly of both abundant and rare fungal taxa along the soil–plant continuums (rhizosphere, phyllosphere and endosphere) in the maize–wheat/barley rotation system under different fertilization practices at two contrasting sites. Our results indicate that mycobiome assembly is shaped predominantly by compartment niche and host species rather than by environmental factors. Moreover, crop-associated fungal communities are dominated by few abundant taxa mainly belonging to Sordariomycetes and Dothideomycetes, while the majority of diversity within mycobiomes are represented by rare taxa. For plant compartments, the abundant sub-community is mainly determined by stochastic processes. In contrast, the rare sub-community is more sensitive to host selection and mainly governed by deterministic processes. Furthermore, our results demonstrate that rare taxa play an important role in fungal co-occurrence network and ecosystem functioning like crop yield and soil enzyme activities. These results significantly advance our understanding of crop mycobiome assembly and highlight the key role of rare taxa in sustaining the stability of crop mycobiomes and ecosystem functions.     

Mitochondrial ubiquitin ligase MARCH5 promotes TLR7 signaling by attenuating TANK action

The signaling of Toll-like receptors (TLRs) is the host's first line of defense against microbial invasion. The mitochondrion is emerging as a critical platform for antiviral signal transduction. The regulatory role of mitochondria for TLR signaling remains to be explored. Here, we show that the mitochondrial outer-membrane protein MARCH5 positively regulates TLR7 signaling. Ectopic expression or knockdown of MARCH5 enhances or impairs NF-κB-mediated gene expression, respectively. MARCH5 interacts specifically with TANK, and this interaction is enhanced by R837 stimulation. MARCH5 catalyzes the K63-linked poly-ubiquitination of TANK on its Lysines 229, 233, 280, 302 and 306, thus impairing the ability of TANK to inhibit TRAF6. Mislocalization of MARCH5 abolishes its action on TANK, revealing the critical role of mitochondria in modulating innate immunity. Arguably, this represents the first study linking mitochondria to TLR signaling.     

黄河三角洲土曲霉Aspergillus terreus OUCMDZ-1925中具抗菌活性的聚酮类天然产物

作者利用化学与生物活性相集成的筛选方法,从采自黄河三角洲地区——东营黄河口的梭鱼Chelon haematocheilus的内脏中分离鉴定了1株耐盐真菌土曲霉Aspergillus terreus OUCMDZ-1925,其发酵产物具有抗枯草芽孢杆菌活性。进一步采用色谱分离、波谱鉴定,从其固体发酵(大米培养基)中分离鉴定了5个化合物,即右旋丁内酯I(1)、丁内酯IV(2)、丁内酯II(3)、丁内酯III(4)和3,5,6-三甲基-2,4-二羟基苯甲酸甲酯(5)。并发现化合物1–3和5对金黄色葡萄球菌(ATCC51650)有强的抑菌活性(最小抑菌浓度均为0.31μg/mL,阳性对照环丙沙星的最小抑菌浓度为0.16μg/mL),化合物1和2对产气杆菌(ATCC13408)以及化合物1和3对枯草芽孢杆菌(ATCC93151)有中等的抑菌活性(最小抑菌浓度分别为6.25μg/mL和12.50μg/mL,阳性对照环丙沙星的最小抑菌浓度分别为1.25μg/mL和5.0μg/mL),化合物1–5对大肠杆菌(ATCC25922)以及化合物4对金黄色葡萄球菌(ATCC51650)有弱的抑制活性,且化合物1的产量高,达2.5g/kg,为其后续研究提供了新的药源。     

Synthesis, crystal structure and magnetic properties of a novel manganese(III) cluster

A polydentate hydroxy-rich Schiff base ligand, derived from the condensation of 3,5-dibromo-2-hydroxybenzaldehyde and 2-ethanolamine, namely 3,5-dibromo- salicylidene-2-ethanolamine (H₂L), reacts with Mn(ClO₄)₂, NaO₂CPiv and NaOCH₃ to give a novel hexanuclear complex [Na^IMn^III₅(μ₃-O²⁻)(μ₄-O²⁻)L₄(O₂CPiv)₃)(ClO₄)]·1.5CH₃OH·0.25H₂O (1). The complex has been characterized by IR, elemental analyses, crystal structural analyses, and magnetic studies. The core in complex 1 features one μ₃-O²⁻ atom, one μ₄-O²⁻ atom, four L²⁻ ligands, three PivCO₂⁻ groups together with a ClO₄⁻ ion bridging five Mn^III atoms and a Na^I atom to form a distorted cubane extended at one face by an incomplete adamantane unit, which is an unprecedented structural type in Mn chemistry. The variable-temperature solid-state dc magnetic susceptibility studies in the 2-300 K range for complex 1 reveal the presence of overall antiferromagnetic intracluster interactions.     

失水-吸水过程中集球藻的生理生化特性研究

荒漠结皮藻类广泛分布于干旱、半干旱地区,经常面临生存水源的短缺。以一种从荒漠结皮中分离的典型绿藻-集球藻(Palmellococcus sp.)为材料,研究其在失水-吸水过程中的某些生理生化特性。即在温室模拟条件下设置相对湿度分别为0%(极度失水)、43%(适度失水)和98%(水合,对照),测定不同失水处理对集球藻光合活性、膜脂过氧化产物丙二醛含量、细胞内可溶性物质含量和抗氧化酶活性的影响,并测定蒸馏水、BBM培养基、0.2 g/L蔗糖溶液、0.2 g/L蓝藻多糖、0.2 g/L脯氨酸和2.5 mmol/L氯霉素及50μmol/L敌草隆进行吸水处理时对失水藻体光合活性的恢复效果。结果表明,与对照处理相比,集球藻在失水过程中光合活性迅速降低,SOD和CAT活性大量升高,细胞内可溶性糖含量和可溶性蛋白含量明显增加,并且膜脂丙二醛含量出现大量积累。不同的失水-吸水处理发现,外源蔗糖和胞外多糖吸水对集球藻的光合活性有较好的恢复作用,添加脯氨酸和氯霉素吸水时光合活性也获得了一定程度的恢复,采用敌草隆吸水时则出现光合活性的明显抑制。研究结果对于更好地理解荒漠结皮绿藻对干旱的生理适应机制提供了有意义的参考。