超氧化物歧化酶、丙二醛、脯氨酸作为裂殖壶菌菌种性能评价的新指标

[目的]对不同Schizochytrium sp.HX-308种子期超氧化物歧化酶(SOD)、丙二醛(MDA)和脯氨酸(Pro)进行测定,旨在寻找出一种评价菌种质量优劣的新方法.[方法]选用Schizochytrium sp.HX-308中的1株驯化高产菌株和1株原始菌株在正常条件下活化,以及同一原始菌株分别在正常条件和恶劣条件下活化的2组实验,分别通过WST-1法、巴比妥酸比色法和比色法测定SOD、MDA和Pro含量,探讨不同菌株中这3个指标与裂殖壶菌Schizochytrium sp.HX-308最终发酵性能之间的关系.[结果]发酵性能最佳的驯化菌株整个种子期的SOD、MDA和Pro含量都最低,平均仅为0.025 U/g、26.20 mmol/g· Fw和0.098 mg/g· Fw,而发酵性能最差的恶劣条件下菌株的SOD已达到了它的6倍以上,MDA和Pro也达到了2倍以上.[结论]本研究最终证实,这3个指标与菌株的发酵性能呈负相关关系,可以作为评价裂殖壶菌菌株发酵性能优劣的新指标,为菌株选育的优化提供了指导.     

Incidence of Inadvertent Intraoperative Hypothermia and Its Risk Factors in Patients Undergoing General Anesthesia in Beijing: A Prospective Regional Survey

Background/Objective

Inadvertent intraoperative hypothermia (core temperature <36⁰ C) is a recognized risk in surgery and has adverse consequences. However, no data about this complication in China are available. Our study aimed to determine the incidence of inadvertent intraoperative hypothermia and its associated risk factors in a sample of Chinese patients.

Methods

We conducted a regional cross-sectional survey in Beijing from August through December, 2013. Eight hundred thirty patients who underwent various operations under general anesthesia were randomly selected from 24 hospitals through a multistage probability sampling. Multivariate logistic regression analyses were applied to explore the risk factors of developing hypothermia.

Results

The overall incidence of intraoperative hypothermia was high, 39.9%. All patients were warmed passively with surgical sheets or cotton blankets, whereas only 10.7% of patients received active warming with space heaters or electric blankets. Pre-warmed intravenous fluid were administered to 16.9% of patients, and 34.6% of patients had irrigation of wounds with pre-warmed fluid. Active warming (OR = 0.46, 95% CI 0.26–0.81), overweight or obesity (OR = 0.39, 95% CI 0.28–0.56), high baseline core temperature before anesthesia (OR = 0.08, 95% CI 0.04–0.13), and high ambient temperature (OR = 0.89, 95% CI 0.79–0.98) were significant protective factors for hypothermia. In contrast, major-plus operations (OR = 2.00, 95% CI 1.32–3.04), duration of anesthesia (1–2 h) (OR = 3.23, 95% CI 2.19–4.78) and >2 h (OR = 3.44, 95% CI 1.90–6.22,), and intravenous un-warmed fluid (OR = 2.45, 95% CI 1.45–4.12) significantly increased the risk of hypothermia.

Conclusions

The incidence of inadvertent intraoperative hypothermia in Beijing is high, and the rate of active warming of patients during operation is low. Concern for the development of intraoperative hypothermia should be especially high in patients undergoing major operations, requiring long periods of anesthesia, and receiving un-warmed intravenous fluids.     

乳白花黄耆(豆科)的一些新异名

通过对模式标本和模式产地标本以及大量腊叶标本的研究,结合野外居群生物学观察,认为科布尔黄耆(Astragalus koburensis Bunge)、宁夏黄耆(A.ningxiaensis Podlech et L.R.Xu)、河套盐生黄耆(Astragalus salsugineus Kar.et Kir.var.hetaoensis H.C.Fu)、德令哈黄耆(Astragalus acceptus Podlech et L.R.Xu)均为乳白花黄耆(Astragalus galactites Pall.)的异名,该文对其进行了订正。     

微生物油脂中花生四烯酸含量的准确快速测定

建立了快速、准确测定微生物油脂中花生四烯酸(ARA)含量的气相色谱检测方法。选用DB-23毛细管色谱柱,设置合适的载气压力,采用FID检测器,对ARA含量进行了定量分析。测定结果表明:油脂中各脂肪酸组分可有效分离,分析时间仅需20 min,ARA的回收率为90.146%~100.634%,相对标准偏差为4.175%。     

微生物发酵产二十二碳六烯酸代谢机理的研究进展

二十二碳六烯酸(简称DHA)是一种重要的长链多不饱和脂肪酸,对人体具有重要的生理功能。微生物发酵生产的DHA与鱼油来源的DHA相比,具有诸多优点,其发展前景广阔。以下从发酵菌株、代谢途径、关键酶以及油脂积累机制等方面进行了综述,为通过代谢工程等技术手段进一步提高DHA产量提供了参考。     

添加生物素和浅蓝菌素对裂殖壶菌发酵产DHA的影响

为提高发酵产量,根据裂殖壶菌生物合成二十二碳六烯酸(DHA)的途径,考察添加代谢途径关键酶的辅酶及酶的抑制剂对发酵裂殖壶菌的影响.结果表明:添加生物素可促进油脂积累,添加浅蓝菌素有利于DHA及不饱和脂肪酸含量的提高.添加生物素0.3 mg/L时,DHA占细胞干质量分数达11.26％,相对于对照提高了13％;当添加浅蓝菌素0.1mg/L时,DHA占细胞干质量分数可达12.2％.     

Fermentation performance and metabolomic analysis of an engineered high-yield PUFA-producing strain of Schizochytrium sp.

Bioprocess and Biosystems Engineering - The ω-3/long-chain polyunsaturated fatty acids (LC-PUFAs) play an important role in human health, but they cannot be synthesized in sufficient amounts...     

Metabolomics profiling reveals the mechanism of increased pneumocandin B<Subscript>0</Subscript> production by comparing mutant and parent strains

Metabolic profiling was used to discover mechanisms of increased pneumocandin B₀ production in a high-yield strain by comparing it with its parent strain. Initially, 79 intracellular metabolites were identified, and the levels of 15 metabolites involved in six pathways were found to be directly correlated with pneumocandin B₀ biosynthesis. Then by combining the analysis of key enzymes, acetyl-CoA and NADPH were identified as the main factors limiting pneumocandin B₀ biosynthesis. Other metabolites, such as pyruvate, α-ketoglutaric acid, lactate, unsaturated fatty acids and previously unreported metabolite γ-aminobutyric acid were shown to play important roles in pneumocandin B₀ biosynthesis and cell growth. Finally, the overall metabolic mechanism hypothesis was formulated and a rational feeding strategy was implemented that increased the pneumocandin B₀ yield from 1821 to 2768 mg/L. These results provide practical and theoretical guidance for strain selection, medium optimization, and genetic engineering for pneumocandin B₀ production.     

新鲜天麻贮藏保鲜的影响因素和相关技术研究进展

鲜天麻是一种营养丰富、功效显著的药食同源药材,但是鲜天麻组织脆嫩、富含微生物,在贮藏和运输过程中极易受到机械损伤和微生物侵害而腐败变质,严重影响其食用和商品价值,因此研究鲜天麻的高效保鲜技术延长其货架期是亟待解决的产业瓶颈问题。综述分析鲜天麻的物理损伤、酶促褐变和内源微生物等腐败机制,并重点阐述了现有物理保鲜技术（臭氧、低温、气调、包装、超高压、60Go-γ辐照处理）、化学保鲜技术（化学保鲜剂、涂膜技术）以及生物保鲜技术（生物保鲜剂、组培技术）的作用原理、方式、保鲜效果、技术缺陷等,旨在为新鲜天麻保鲜技术研究提供参考,促进鲜天麻资源发展。