Simultaneous nitrogen and carbon removal in a packed A/O reactor: effect of C/N ratio on microbial community structure

In this research, a novel packed anoxic/oxic moving bed biofilm reactor (MBBR) was established to achieve high-organic matter removal rates, despite the carbon/nitrogen (C/N) ratio of 2.7–5.1 in the influent. Simultaneous nitrification–denitrification (SND) was investigated under a long sludge retention time of 104 days. The system exhibited excellent performance in pollutant removal, with chemical oxygen demand and total nitrogen (TN) enhanced to 93.6–97.4% and 34.4–60%, respectively. Under low C/N conditions, the nitrogen removal process of A/O MBBR system was mainly achieved by anaerobic denitrification. The increase of C/N ratio enhanced SND rate of the aerobic section, where dissolved oxygen was maintained at the range of 4–6 mg/L, and resulted in higher TN removal efficiency. The microbial composition and structures were analyzed utilizing the MiSeq Illumina sequencing technique. High-throughput pyrosequencing results indicated that the dominant microorganisms were Proteobacteria and Bacteroidetes at the phylum level, which contributes to the removal of organics matters. In the aerobic section, abundances of Nitrospirae (1.12–29.33%), Burkholderiales (2.15–21.38%), and Sphingobacteriales (2.92–11.67%) rose with increasing C/N ratio in the influent, this proved that SND did occur in the aerobic zone. As the C/N ratio of influent increased, the SND phenomenon in the aerobic zone of the system is the main mechanism for greatly improving the removal rate of TN in the aerobic section. The C/N ratio in the aerobic zone is not required to be high to exhibit good TN removal performance. When C/NH₄⁺ and C/TN in the aerobic zone were higher than 2.29 and 1.77, respectively, TN removal efficiency was higher than 60%, which means that carbon sources added to the reactor could be saved. This study would be vital for a better understanding of microbial structures within a packed A/O MBBR and the development of cost-efficient strategies for the treatment of low C/N wastewater.

     

An auto-inducible expression and high cell density fermentation of Beefy Meaty Peptide with Bacillus subtilis

Bioprocess and Biosystems Engineering - Currently, some cases about the expression of flavor peptides with microorganisms were reported owing to the obvious advantages of biological expression over...     

莫西沙星联合用药方案对耐多药肺结核患者血清游离氨基酸和免疫功能的影响

目的:探讨莫西沙星联合用药方案对耐多药肺结核(MDR-TB)患者血清游离氨基酸和免疫功能的影响。方法:选取2015年9月到2018年1月期间我院收治的90例MDR-TB患者,根据乱数表法将患者分为研究组(n=45)、对照组(n=45),其中对照组给予左氧氟沙星联合常规化疗治疗,研究组则给予莫西沙星联合常规化疗治疗,比较两组临床疗效、痰菌转阴率、病灶吸收率、空洞闭合率、血清游离氨基酸和免疫功能,记录两组治疗期间不良反应情况。结果:研究组治疗18个月后的临床总有效率为71.11%(32/45),高于对照组的46.67%(21/45)(P0.05)。研究组治疗18个月后痰菌转阴率、病灶吸收率、空洞闭合率均较对照组高(P0.05)。两组患者治疗18个月后CD4+、免疫球蛋白A(Ig A)、免疫球蛋白G(Ig G)均升高,CD8+降低(P0.05),研究组治疗18个月后CD4+、Ig A、Ig G高于对照组,而CD8+低于对照组(P0.05)。两组治疗18个月后缬氨酸、谷氨酸均升高,且研究组高于对照组(P0.05)。两组患者总不良反应发生率比较无明显差异(P0.05)。结论:莫西沙星联合常规化疗治疗MDR-TB的疗效确切,可有效改善患者血清游离氨基酸水平,提高机体免疫功能,同时不增加不良反应发生率。     

脑缺血大鼠肺组织NGF/TrkA表达变化及其意义

目的:探讨大鼠脑缺血后肺组织神经生长因子(nerve growth factor,NGF)/酪氨酸蛋白激酶A(tropomyosin-related kinase A,TrkA)表达的变化。方法:成年雄性大鼠随机分为假手术组和脑缺血后6 h、24 h及48 h组,每组8只。建立大脑中动脉永久性局灶性缺血模型,术后于各时间点麻醉处死大鼠后,测定肺组织湿重/干重(W/D),光镜下观察HE染色肺组织病理学改变;Western blot法检测肺组织NGF、TrkA蛋白表达。结果:与假手术组相比,脑缺血后6 h肺组织W/D有增加,差异无统计学意义(P>0.05),而脑缺血后24 h及48 h肺组织W/D均有显著增高(P<0.05),其中以24 h组最明显(P<0.01);脑缺血后6 h肺组织出现轻度充血、水肿及炎性改变,24 h及48 h组肺泡结构破坏明显。病理学评分结果显示,脑缺血后24 h及48 h组大鼠肺组织病理评分较假手术组显著升高(P<0.05);Western blot法显示,脑缺血6 h肺组织中NGF表达增加(P<0.05),48 h时表达有下降趋势,但仍高于假手术组(P<0.05)。而肺组织中TrkA表达在脑缺血6h有下降(P>0.05),24 h下降明显(P<0.05),48 h时TrkA蛋白表达虽有上升,仍显著低于假手术组(P<0.05)。结论:大鼠肺组织NGF/TrkA的动态变化可能参与了脑缺血后肺损伤的病理生理过程。     

不同浓度罗哌卡因腰硬联合麻醉用于人工髋关节置换手术对患者麻醉效果和术后运动功能的影响

摘要 目的：探讨不同浓度罗哌卡因腰硬联合麻醉用于人工髋关节置换手术对患者麻醉效果和术后运动功能的影响。方法：2017年2月至2019年12月选择在本院进行人工髋关节置换手术的患者84例,根据随机数字表法把患者分为观察组与对照组各42例。两组都给予腰硬联合麻醉,对照组采用常规浓度0.5 %罗哌卡因麻醉观察组采用低浓度0.375 %罗哌卡因麻醉,记录患者麻醉效果和术后运动功能变化情况。结果：观察组的麻醉持续时间、运动恢复时间和感觉运动时间都显著短于对照组(P<0.05)。观察组麻醉后10 min、30 min、60 min的Bromage评分都低于对照组(P<0.05)。观察组术后7 d的低血压、恶心呕吐、头晕头痛、尿潴留等不良反应发生率为7.1 %,显著低于对照组的19.0 %(P<0.05)。两组所有患者在术后2 h、术后4 h、术后24 h的呼吸、心率均在正常范围内波动,组间与组内对比都无统计学意义(P>0.05)。结论：低浓度罗哌卡因腰硬联合麻醉用于人工髋关节置换手术能改善患者的麻醉效果和运动功能,提高麻醉效果,并不影响患者的生命体征,且能减少术后不良反应的发生。     

Long-Term Existence of SARS-CoV-2 in COVID-19 Patients: Host Immunity,Viral Virulence,and Transmissibility

Virologica Sinica - COVID-19 patients can recover with a median SARS-CoV-2 clearance of 20&nbsp;days post initial symptoms (PIS). However, we observed some COVID-19 patients with existing...     

Epidermal growth factor improves intestinal morphology by stimulating proliferation and differentiation of enterocytes and mTOR signaling pathway in weaning piglets

Epidermal growth factor(EGF) has been shown to improve piglet intestinal morphology and epithelial recovery. In an attempt to further understand the mechanisms behind these improvements, this study tested the hypothesis that dietary EGF may affect intestinal morphology by stimulating the proliferation and differentiation of enterocytes in weaning piglets. In piglets receiving200 μg kg–1 EGF, crypt depth and villus height increased(P0.05). Adding 400 μg kg–1 EGF increased villus height-to-crypt depth ratio(P0.05), but reduced crypt depth(P0.05). Dietary supplementation with 200 μg kg–1 EGF significantly increased the number of Ki67-positive cells(P0.01) and tended to increase the mRNA level of proliferating cell nuclear antigen(P0.10).However, this supplementation decreased the expression level of intestinal fatty acid-binding protein(P0.05). Piglets fed with400 μg kg–1 EGF had an increased mRNA level of intestinal alkaline phosphatase(P0.05). The phosphorylation of m TOR(mammalian target of rapamycin) was observed in the 200 μg kg–1 EGF group. These results suggest that dietary supplementation with a low level of EGF improved piglet intestinal morphology through stimulating the proliferation and differentiation of enterocytes, and the mTOR signaling pathway may partly be involved in this process.     

应用iTRAQ技术分析滩羊二毛期不同花穗型裘皮差异蛋白

为了解二毛期时滩羊串子花型裘皮与其它类型裘皮中蛋白质的差异,本试验采用iTRAQ技术及LC-MS/MS蛋白质组学研究方法,对串子花型、软大花型、绿豆丝型及其它不规则型花穗裘皮蛋白质进行鉴定和筛选,并运用Proteome Discoverer l.4软件进行定量分析,结合数据库搜索,鉴定出具有显著表达差异的蛋白,同时应用生物学技术对其进行GO和Pathway分析。结果显示4类花穗型裘皮共检测出2 886个蛋白,其中有135个、142个、113个差异蛋白分别存在于软大花型与串子花型、绿豆丝型与串子花型、其它不规则型与串子花型3个对比组中。对有表达差异的蛋白进行分析,发现膜联蛋白与血管内皮生长因子可能与软大花型毛股形成相关,KAP3和KAP6可能与滩羊串子花型毛股结构相关。研究发现滩羊不同二毛裘皮蛋白水平上的差异,可为选育优良的滩羊串子花型二毛裘皮提供理论基础。     

秋葵籽油对高强度运动所致肝损伤的保护作用

本研究考察了秋葵籽油对高强度运动所致肝损伤的保护作用及机制。研究显示,对昆明小鼠灌胃不同剂量(10 mg/kg,20 mg/kg和50 mg/kg)的秋葵籽油4周后,秋葵籽油以剂量依赖性方式提高了小鼠的力竭游泳时间(p<0.05)。秋葵籽油降低了小鼠血清乳酸和尿素氮水平,并升高了血清游离脂肪酸和肝糖原水平(p<0.05)。秋葵籽油以剂量依赖性方式提高了小鼠肝脏组织中SOD、CAT和GSH-Px活性,并抑制了MDA的合成(p<0.05)。秋葵籽油抑制了力竭游泳诱导的小鼠血清CK、AST和ALT水平及肝脏组织NO水平的升高(p<0.05)。此外,苏木精和伊红(HE)染色证实了秋葵籽油减轻了力竭游泳诱导的肝脏病理改变。因此,本研究初步结论表明,在高强度运动过程中,秋葵籽油可通过抑制乳酸和尿素氮的积累、增加脂肪动员、降低糖原消耗、减弱氧化应激损伤等多种途径来对肝脏发挥保护作用。     

发菜磷酸葡糖胺变位酶(glmM)对干旱胁迫的响应及其基因克隆

glmM编码的磷酸葡糖胺变位酶是肽聚糖合成前体的关键酶。为探究发菜glmM响应干旱胁迫的表达调控机制及明确其分子信息,本研究对干旱胁迫条件下发菜glmM在转录水平的差异表达进行了分析,并对glmM的表达水平、磷酸化修饰、乙酰化修饰和琥珀酰化修饰水平进行了检测,克隆了发菜glmM,进行了序列分析和原核表达。结果表明,干旱胁迫条件下,发菜glmM在转录水平上的表达量先增加后减少,glmM上调表达,glmM的磷酸化修饰水平逐渐增加,乙酰化修饰水平相对稳定,琥珀酰化修饰水平有明显变化。设计特异性引物克隆glmM基因,获得全长1416 bp发菜glmM基因,与肺衣(5183)glmM的核苷酸序列同源性为95%,氨基酸同源性为97%。将glmM在大肠杆菌中表达,获得一个51.45 kD的外源蛋白,MALDI-TOF-TOF/MS分析证明该蛋白为磷酸葡糖胺变位酶。研究结果为深入研究发菜glmM的分子信息、生物学功能及其响应干旱胁迫的分子机制提供帮助。