Lipidomic analysis of lipid droplets from murine hepatocytes reveals distinct signatures for nutritional stress

Liver steatosis can be induced by fasting or high-fat diet. We investigated by lipidomic analysis whether such metabolic states are reflected in the lipidome of hepatocyte lipid droplets (LDs) from mice fed normal chow diet (FED), fasted (FAS), or fed a high-fat diet (HFD). LC-MS/MS at levels of lipid species profiles and of lipid molecular species uncovered a FAS phenotype of LD enriched in triacylglycerol (TG) molecular species with very long-chain (VLC)-PUFA residues and an HFD phenotype with less unsaturated TG species in addition to characteristic lipid marker species. Nutritional stress did not result in dramatic structural alterations in diacylglycerol (DG) and phospholipid (PL) classes. Moreover, molecular species of bulk TG and of DG indicated concomitant de novo TG synthesis and lipase-catalyzed degradation to be active in LDs. DG species with VLC-PUFA residues would be preferred precursors for phosphatidylcholine (PC) species, the others for TG molecular species. In addition, molecular species of PL classes fitted the hepatocyte Kennedy and phosphatidylethanolamine methyltransferase pathways. We demonstrate that lipidomic analysis of LDs enables phenotyping of nutritional stress. TG species are best suited for such phenotyping, whereas structural analysis of TG, DG, and PL molecular species provides metabolic insights.     

Provenance selection and site conditions determine growth performance of pedunculate oak

Forests of the future need to cope with adverse climatic conditions, in particular drought, to ensure forest stability and productivity. Given the usually long rotation period of forests, forest managers need to select appropriate, i.e. productive and climate-change resilient tree species and/or provenances, to lower tree-mortality risks and sustain current wood production rates at the end of the 21^st century. A frequent means of assessing which provenances of a given species are adapted to anticipated climate conditions is common garden experiments, where trees from different provenances are planted under similar climate conditions. However, in this context soil conditions also play an important role, since they govern how climate translates into plant-available water and hence plant’s ability to cope with extreme drought events. Here, we examine the effects of soil conditions on pedunculate oak (Quercus robur L.), by studying 10 different Dutch oak provenances that were planted in three provenance trials on different soil types in 1988 in the Netherlands. Using dendroecological methods, we quantified provenance-specific productivity and assessed provenance- and site-specific growth patterns. Our results indicated clear differences in productivity among provenances as well as soil-type specific growth patterns. Consequently, our study highlights the importance of incorporating soil characteristics when evaluating the growth performance of provenances within common garden experiments.     

基于主因子分析的生态社区评价方法研究——以上海外环以内区域为例

从生态系统和可持续发展理论出发,构建了生态社区评价的指标体系,运用主因子分析方法建立了生态社区评价模型;并在遥感与GIS技术支持下,对上海中心城区做了生态社区评价研究.结果表明,在空间格局上,社区生态水平差异明显,无论是在社区内部还是社区之间,各主因子分布极不平衡;总体看来,浦西核心区的大部分社区,其规模结构比较合理,服务设施比较完善,然而部分社区的生态环境质量急需要改善,部分社区的居住条件也需要进一步完善;而浦东一些社区,尽管生态指数较高,生态环境质量较好,但由于基础配套设施不够健全,规模结构不够均衡,道路交通系统尚待进一步完善.     

珍稀药用真菌桑黄的国内外研究进展

桑黄是一种十分珍贵的药用真菌,对增强人体免疫功能及治疗疾病等方面都有明显作用。综述了近年来国内外学者对桑黄的名称、地区分布、化学成分、药理作用等方面的研究进展。     

细穗玄参的化学成分研究-Ⅱ

从细穗玄参(S crof ella ch inensisM ax im.)全草的正丁醇提取物中分离并鉴定了6个化合物,利用现代波谱技术(M S1、H NM R1、3C NM R、DEPT、HM BC、HM QC)和化学方法进行结构鉴定,分别为6-O-(2″-对羟基反式肉桂酸-α-L-鼠李糖)梓醇(1)、山栀子苷(2)、桃叶珊瑚苷(3)、玉叶金花苷酸(4)、熊果苷(5)、肌氨酸乙酯(6).6个化合物均为首次从该植物中发现.     

A physiological description of critical velocity

Although critical velocity (CV) provides a valid index of aerobic function, the physiological significance of CV is not known. Twelve individuals performed exhaustive runs at 95% to 110% of the velocity at which VO2max was attained in an incremental test. VO2max was elicited in each run. Using the time to exhaustion at each velocity, CV was calculated for each participant. Using the time to achieve VO2max at each velocity, which was shorter at higher velocities, a parameter we have designated as CV' was calculated for each participant. During exercise at or below CV', VO2max cannot be elicited. CV (238+/-24 m x min(-1)) and CV' (239+/-25 m x min(-1)) were equal (t = 0.60, p = 0.56) and correlated (r = 0.97, p < 0.01). These results demonstrate that CV is the threshold intensity above which exercise of sufficient duration will lead to attainment of VO2max.     

Volatile metabolic profiles of cell suspension cultures of Lavandula vera,Nicotiana tabacum and Helianthus annuus,cultivated under different regimes

Cell suspension cultures of Lavandula vera (Lamiaceae), Nicotiana tabacum (Solanaceae), and Helianthus annuus (Asteraceae) were cultivated in three different ways: in shake flasks both as free suspensions and in two‐phase systems (in the presence of Amberlite XAD‐4 resin as a second phase), as well as in 3‐L stirred tank reactor, and their volatile metabolic profiles were studied using GC‐MS. A number of compounds, some of them having allelochemical and biological activities, were identified in all the three cell suspension cultures under study. Also the presence of some compounds, unusual for the intact plants, was observed. It was found that the cultivation mode strongly influences the production and the transport (secretion into the culture medium) of the low‐molecular‐mass volatile metabolites. Principal component analyses of 12 common hydrocarbons showed discrimination between the different cultivation modes (shake flasks and two‐phase systems cultivation) by first principal component (PC1) and second principal component (PC2).     

中草药提取物中缩合类单宁的选择性脱除

以皮胶原纤维为原料,通过甲醛交联反应制备吸附材料。采用外加单宁的方法研究了这种吸附材料对中草药提取物中缩合类单宁的选择性吸附能力。结果表明,胶原纤维吸附材料对落叶松单宁、黑荆树单宁和杨梅单宁等3种典型的缩合类单宁都具有非常好的吸附选择性,在实验条件下单宁的去除率达到100％,而对有效成份的吸附率较低。该吸附材料对与缩合类单宁具有相似结构的低聚原花青素的吸附率也较低。对比试验表明,胶原纤维吸附材料对单宁的吸附选择性优于聚酰胺。     

环境噪声对临安和阜阳两地白头鹎鸣声频率的影响

为了解环境噪声对白头鹎(Pycnonotus sinensi)鸣声频率的影响,在浙江临安和安徽阜阳两地分别对白头鹎在高低噪声水平环境中的鸣声做了研究。把用数码录音机记录到的鸣声输入计算机,利用计算机声谱分析系统进行分析,再对每一鸣声的每个音节的主频进行Mann—Whitney U检验。结果显示：高噪声水平区和低噪声水平区相比,在两地白头鹎每一鸣声的各音节主频中,最低和最高主频以及第I、Ⅱ音节的主频都有显著提高;在阜阳第Ⅲ音节的主频也有显著提高。这表明白头鹎可以通过提高声音频率来避免环境噪声对鸣声的影响,从而保证噪声环境中声信息的有效传递;而噪声对各音节的不同影响也表明,同一鸣句的各音节,对于噪声通讯中的信息识别,具有不同的地位。     

Histidine kinases in plants: Cross talk between hormone and stress responses

Two-component signaling pathways involve sensory histidine kinases (HK), histidine phosphotransfer proteins (HpT) and response regulators (RR). Recent advancements in genome sequencing projects for a number of plant species have established the TCS family to be multigenic one. In plants, HKs operate through the His–Asp phosphorelay and control many physiological and developmental processes throughout the lifecycle of plants. Despite the huge diversity reported for the structural features of the HKs, their functional redundancy has also been reported via mutant approach. Several sensory HKs having a CHASE domain, transmembrane domain(s), transmitter domain and receiver domain have been reported to be involved in cytokinin and ethylene signaling. On the other hand, there are also increasing evidences for some of the sensory HKs to be performing their role as osmosensor, clearly indicating toward a possible cross-talk between hormone and stress responsive cascades. In this review, we bring out the latest knowledge about the structure and functions of histidine kinases in cytokinin and ethylene signaling and their role(s) in development and the regulation of environmental stress responses.