益生菌干预对肥胖孕鼠子代菌群及脂代谢的影响

目的分析高脂高糖饮食诱导肥胖母亲对子代菌群及脂代谢影响。方法C57BL/6J雌性小鼠30只随机分为正常对照组、肥胖组、益生菌干预组,每组10只。分别给予标准饲料、高脂高糖饲料以及高脂高糖饲料同时给予益生菌,连续喂养6周,制成肥胖母鼠模型。6周后雌、雄鼠合笼,受孕,孕期继续上述饮食。产后母乳喂养,3周后处死。留取雌性子鼠第21天粪便样本进行PCR-DGGE分析,同时酶反应比色法分析子鼠血脂情况。结果与正常对照组子代相比,肥胖母鼠子代菌群结构出现异常,益生菌干预组子代肠道菌群失调状况明显改善;肥胖母鼠子代血清总胆固醇、低密度脂蛋白含量升高,益生菌干预组子代血脂异常情况明显改善。结论高脂高糖饮食诱导肥胖母亲子代存在肠道菌群紊乱及脂代谢异常,益生菌干预母亲有利于改善子代菌群紊乱及脂代谢异常。     

益生菌干预对肥胖小鼠肝脏miR-33 和miR-122表达的影响

目的探讨益生菌干预对高脂饮食诱导肥胖小鼠肝脏miR-33和miR-122表达的影响。方法 18只雌性C57BL/6J小鼠随机分为对照组、肥胖组和益生菌干预组,每组6只,分别给予标准饲料、高脂饲料以及高脂饲料+益生菌合剂灌胃,自由采食及饮水,连续喂养6周。每周测量3组小鼠的体质量,6周后,留取小鼠血液样本采用全自动生化仪检测小鼠血脂,安乐法处死小鼠,留取小鼠肝脏样本Hair-pin RT-PCR法检测miR-33和miR-122的含量。结果与对照组小鼠相比,肥胖组小鼠体质量明显增加(t_(2周)=3.985,t_(3周)=4.751,t_(4周)=4.380,t_(5周)=4.728,t_(6周)=4.112,均P0.01);益生菌干预组小鼠体质量较肥胖组明显降低(t_(3周)=3.694,t_(4周)=4.415,t_(5周)=3.752,t_(6周)=3.392,均P0.01);肥胖组小鼠血清总胆固醇、低密度脂蛋白含量较对照组明显升高(t=10.850,t=7.024,均P0.01),益生菌干预组小鼠较肥胖组小鼠血清总胆固醇、低密度脂蛋白含量降低(t=3.034,t=2.881,均P0.05),但与对照组仍有差异。与对照组小鼠相比,肥胖组小鼠肝脏miR-122的表达升高(t=9.170,P0.01),miR-33的表达降低(t=3.420,P0.05),益生菌干预组小鼠较肥胖组小鼠miR-122的表达降低(t=3.204,P0.05),miR-33的表达升高(t=2.070,P0.05)。结论益生菌干预能够影响高脂饮食小鼠肝脏miR-33和miR-122的表达,这可能是益生菌干预改善高脂饮食小鼠肝脏脂代谢的机制之一。     

16S rDNA测序研究高脂饮食诱导的高脂血症大鼠肠道菌群变化

目的 通过高脂饮食诱导大鼠高脂血症,采用16S rDNA测序检测高脂血症大鼠肠道菌群变化情况.方法 SD大鼠20只(清洁级),按体质量随机分为模型组和对照组,对照组大鼠给予维持饲料,模型组大鼠给予高脂饲料.1周后检测血清总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)和高密度脂蛋白胆固醇(HDL-C...     

不同配方益生菌在高脂饮食诱导小鼠肥胖发生中的差异化作用

【目的】基于肠道微生物与宿主代谢的相互关系,研究不同配方的益生菌对小鼠肥胖的影响。【方法】50只C57BL/6J雄性小鼠随机平均分成10组,分别给予正常饲料、高脂饲料以及高脂饲料加8种不同配方的益生菌产品(50亿CFU/只),所有动物连续喂养9周,每周测量小鼠体重1次。最后一周测定空腹血糖、葡萄糖耐量试验(glucose tolerance test,GTT)、血脂相关指标,称取内脏重量,并留取小鼠盲肠内容物,提取小鼠肠道菌群总DNA,利用16S rDNA测序检测相关细菌含量。【结果】部分益生菌可引起小鼠体重增速加快,而部分益生菌可减缓小鼠肥胖和降低内脏脂肪重量,同时缓解高血脂症。丹尼斯克品牌益生菌配方组小鼠肠道中厚壁菌/拟杆菌比例(F/B)是正常饮食组的22.8倍,Akkermansia muciniphila(Akkermansia)细菌含量几乎为0;而菌拉丁品牌益生菌配方组小鼠F/B比例与正常饲料饮食组类似,Akkermansia含量为0.5%,为正常饮食对照组小鼠的一半左右。【结论】益生菌可影响小鼠体重和代谢,但不同配方的益生菌效果截然相反。特定的益生菌配方对肥胖和高血脂的改善可能是由于其选用的菌株本身的特性以及菌株之间的相互配比能够降低小鼠肠道中F/B比例以及升高Akkermansia的含量所带来的。此研究为进一步开发可改善代谢的益生菌产品提供了参考。     

Nrf2激动剂CDDO-Im对高脂饮食诱导的肥胖小鼠肝脏脂肪变性的影响

摘要 目的：探究Nrf2激动剂CDDO-Im对高脂饮食诱导的肥胖小鼠肝脏脂肪变性的作用。方法：33只雄性C57BL/6J小鼠随机分为两组：一组16只饲喂普通饲料,另一组17只饲喂高脂饲料建立肥胖模型。造模成功后将小鼠随机分成四组：普通饲料溶剂对照组（Control ND组）、普通饲料Nrf2激动剂组（Nrf2(+) ND组）、高脂饲料溶剂对照组（Control HFD组）和高脂饲料Nrf2激动剂组（Nrf2(+) HFD组）。分别给予Nrf2激动剂CDDO-Im和等体积溶剂灌胃干预6周后,检测各组小鼠血清甘油三酯（TG）、总胆固醇（T-CHO）和低密度脂蛋白-胆固醇（LDL-C）。苏木素-伊红（HE）染色观察肝脏组织形态学变化。RT-qPCR检测肝脏Nrf2下游抗氧化基因Nqo1、Ho1和Gclc的mRNA表达水平,Western Blot检测肝脏NQO1、HO-1和GCLC的蛋白表达水平。结果：与正常小鼠相比,肥胖小鼠的体重、TG和LDL-C升高（P＜0.05）,肝脏脂肪变性增加,GCLC的蛋白表达水平降低（P＜0.05）。在肥胖小鼠中,与溶剂对照组相比,Nrf2激动剂组小鼠的体重、血清TG降低（P＜0.05）,肝脏脂肪变性减轻,Nqo1和Gclc的mRNA表达水平升高（P＜0.05）,NQO1和GCLC的蛋白表达水平升高（P＜0.05）。结论：Nrf2激动剂CDDO-Im可改善高脂饮食诱导的肥胖小鼠肝脏脂肪变性,可能与Nrf2激动剂CDDO-Im激活抗氧化基因的表达来减轻肝细胞氧化应激有关。     

泽泻对高脂高糖饮食大鼠肠道菌群多样性的影响

目的研究泽泻对高脂高糖饮食大鼠的降血脂作用与肠道菌群多样性的相关性,并测定高脂高糖饮食大鼠肠道菌群丰度与多样性的变化。方法将32只健康雄性SD大鼠随机分成正常组(control group,CON)、高脂高糖模型组(high-fat and high-sucrose diet group,HFS)、高脂高糖饲料加二甲双胍干预组(metformin treatment group,MET)和高脂高糖饲料加泽泻醇提取物干预组(Alisma orientale extract group,AOE)。每组8只,造模4周后分别灌胃给予相应药物,连续4周。CON组和HFS组灌胃给予生理盐水。检测血清TC、TG、LDL-C及HDL-C水平及其他指标,提取肠道菌群总DNA,分析肠道微生物的变化。结果 HFS组的TC、LDL-C水平明显高于CON组(Ps0.05),给药4周后,AOE组TC、LDL-C水平均显著性降低(Ps0.05)。高通量测序结果显示,AOE组中与脂质代谢、多聚糖生物合成与代谢相关的肠道菌群多样性及丰度增加显著,肠道菌群的生态环境得以改善,形成了新的肠道菌群稳态。结论泽泻醇提取物可以有效降低高脂高糖饮食大鼠的血脂水平,对其肝脏具有保护作用。泽泻醇提取物也能通过改变肠道菌群的丰度、多样性和功能类群等靶标进行脂质代谢调节。     

乌龙茶多酚对高脂饮食诱导肥胖小鼠模型肠道菌群的调节作用

为了研究乌龙茶多酚(Oolong tea polyphenols,OTP)对肥胖小鼠肠道微生物群的调节作用,本文采用高脂饮食诱导小鼠肥胖后,通过高通量测序技术分析其对肠道菌群结构的影响。结果表明,OTP能够明显抑制高脂喂养小鼠肥胖的形成、减轻肝脏脂肪变性、降低血清中总胆固醇(Total cholesterol,TC)、甘油三酯(Triglyceride,TG)、低密度脂蛋白胆固醇(Low density lipoprotein cholesterol,LDL-C)含量以及增加高密度脂蛋白胆固醇(High density lipoprotein cholesterol,HDL-C)的含量(P0.05)。进一步分析显示,OTP能够抑制高脂饮食导致的小鼠肠道菌群丰度及多样性的降低。从微生物群落结构上看,补充8周OTP后,可以观察到肥胖小鼠肠道中拟杆菌门(Bacteroidetes)的增加和厚壁菌门(Firmicutes)的减少,Firmicutes/Bacteroidetes比率相应降低,该实验结果表明OTP对肠道菌群具有一定的调节作用。因此,OTP可能具有益生元活性,可作为功能性食品成分预防肠道菌群生态的失调,并具有治疗肠道微生物功能失调的潜在治疗效用。     

基于肠道菌群和短链脂肪酸代谢探讨不同饮食条件下高脂血症大鼠发病机制

目的 本研究拟对比两种不同高脂饮食方式诱导的高脂血症大鼠肠道菌群变化与短链脂肪酸代谢特征,以宿主-肠道菌群-代谢角度探讨高脂血症可能的微观机制。方法 SPF级SD大鼠分为：正常饮食组(CG组):饲喂大鼠维持饲料;高脂饮食组(HFD1组):每天足量饲喂高脂饲料;限饲高脂饮食组(HFD2组):每天限量饲喂高脂饲料80 g,不限量饲喂维持饲料。8周后检测血清总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL-C)和高密度脂蛋白胆固醇(HDL-C)水平;苏木精-伊红(HE)染色观察大鼠肝组织和肾周脂肪病理学变化;取结肠内容物进行16S rDNA高通量测序,观察肠道菌群结构与功能的变化,并检测结肠内容物中短链脂肪酸的含量。结果 与CG组相比,HFD1组和HFD2组大鼠摄食量下降,体重升高;血清中TC、TG、LDL-C均显著升高;肝组织发生明显脂肪变性,肾周脂肪出现炎性病变;高脂干预后大鼠肠道菌群相对丰度显著变化,其中乳杆菌属相对丰度明显降低,菌群结构和功能变化明显,总短链脂肪酸、乙酸、丁酸、异丁酸下降显著。结论 两种高脂饮食方式均能引起大鼠高脂血症,且发病机制基本一致,均与脂质代谢以...     

野生蓝莓和花青素提取物对高脂饮食小鼠肠道菌群的影响

【目的】研究野生蓝莓和花青素提取物对高脂饮食小鼠肠道菌群的影响。【方法】采用高脂饲料喂养C57BL/6小鼠,同时膳食补充野生蓝莓或花青素提取物,将25只无菌小鼠分为5组:正常对照组(Normal chow diet,NCD),普通饲料+10 g/100 g蓝莓组(NCD+BB),高脂饲料组(High-fat diet,HFD),高脂饲料+10 g/100 g蓝莓组(HFD+BB),高脂饲料+20 mg/100 g花青素组(HFD+ACN),饲养10周,每周对其食物摄入量、能量摄入量以及体重进行测定,并运用DGGE方法对小鼠肠道菌群结构变化进行动态监测。【结果】各实验组食物摄入量无显著性差异,HFD+BB组和HFD+ACN组能量摄入量均明显高于NCD+BB组。虽然HFD+BB组体重增加最为明显,但10周末时HFD+BB组体重与其他各组无显著差异。随着实验的进行,HFD组、HFD+BB组和HFD+ACN组肠道微生物多样性发生明显变化。HFD+BB组与NCD组菌群差异最大,HFD+ACN组与NCD组肠道菌群DGGE图谱相似性系数明显高于HFD组,对优势条带测序结果显示膳食补充蓝莓或花青素提取物可明显降低肥胖相关细菌Firmicutes的数量。【结论】蓝莓和花青素提取物可改善由高脂饮食引起的肠道微生态失调,调节肠道菌群结构,具有潜在的减肥消脂功能。     

高脂饮食对小鼠脂质代谢和leptin基因表达水平的影响

目的建立高脂饮食诱导小鼠肥胖模型,分析高脂饲料对小鼠脂质代谢和leptin基因表达水平的影响。方法用高脂饲料饲喂小鼠,每周定时称重和断尾采血一次,分别测定血清中血糖、胆固醇、甘油三酯、胰岛素和leptin的浓度;5周后,分离、称重小鼠体脂并提取腹部脂肪组织RNA,半定量RT-PCR分析leptin基因表达水平。结果从第2周开始,实验组小鼠体重明显高于对照组小鼠,4周后,体重差异显著（P〈0．05）;血清中血糖、胆固醇、甘油三酯、胰岛素和leptin的含量随体重增加明显增高,4周后,差异显著（P〈0．05）;实验组体脂含量明显高于对照组（P〈0．05）,半定量RT-PCR分析表明,肥胖小鼠脂肪组织leptin基因表达水平高于对照组（P〈0．05）。结论高脂饮食诱导可建立小鼠肥胖模型,并能够引起高胰岛素和高leptin血症,为进一步研究肥胖的发病机制奠定基础。     

Biomimetic polysaccharide nanocomposites of high cellulose content and high toughness

Plant cell walls combine mechanical stiffness, strength and toughness despite a highly hydrated state. Inspired by this, a nanostructured cellulose network is combined with an almost viscous polysaccharide matrix in the form of a 50/50 amylopectin-glycerol blend. Homogeneous films with a microfibrillated cellulose (MFC) nanofiber content in the range of 10-70 wt % are successfully cast. Characterization is carried out by dynamic mechanical analysis, field-emission scanning electron microscopy, X-ray diffraction, and mercury density measurements. The MFC is well dispersed and predominantly oriented random-in-the-plane. High tensile strength is combined with high modulus and very high work of fracture in the nanocomposite with 70 wt % MFC. The reasons for this interesting combination of properties include nanofiber and matrix properties, favorable nanofiber-matrix interaction, good dispersion, and the ability of the MFC network to maintain its integrity to a strain of at least 8%.     

Adaptation of proteins from hyperthermophiles to high pressure and high temperature

Further clarification of the adaptations permitting the persistence of life at temperatures above 100 degrees C depends in part on the analysis of adaptive mechanisms at the protein level. The hyperthermophiles include both Bacteria and Archaea, although the majority of isolates growing at or above 100 degrees C are Archaea. Newly described adaptive features of hyperthermophiles include proteins whose structural integrity persists at temperatures up to 200 degrees C, and under elevated hydrostatic pressure, which in some cases adds significant increments of stability.     

高寒生态系统微生物群落研究进展

高寒生态系统分布在高纬度或高海拔、气候寒冷的地区,包括北极苔原、高山苔原、青藏高原等.高寒生态系统对气候变化非常敏感,其土壤中储存大量的有机碳,对全球的碳平衡起关键作用.微生物是生物地球化学循环的主要驱动者,微生物群落对气候变化的响应和反馈影响生态系统的功能与稳定性.本文回顾了高寒生态系统微生物群落组成、多样性与空间分布,以及微生物群落对气候变化(增温、氮沉降、火干扰)的响应,为拓展我国高寒生态系统微生物研究提供基础.     

Sows with high milk production had both a high feed intake and high body mobilization

Selection for increased litter size have generated hyper-prolific sows that nurses large litters, however limited knowledge is available regarding the connection between milk production, feed intake and body mobilization of these modern sows. The aim of the current study was to determine what characterized sows with high milk production and nursing large litters, differences between sows of different parities and effects of lactational performance on next reproductive cycle. In total 565 sows (parity 1 to 4) were studied from 7 days before farrowing until weaning. On day 2 postpartum litters were standardized to 14 piglets. Weight and back fat thickness of sows were measured at day 7 prepartum, day 2 postpartum and at weaning. Litters were weighed at day 2 and at weaning. Pearson correlation coefficients between variables were calculated and regression models were developed. The average daily feed intake (ADFI) of the sows was 6.1±1.1 kg/day, average daily gain (ADG) of the litter was 2.92±0.53 kg/day and sows weaned 13.0±1.1 piglets. First parity sows generally had a lower ADFI and milk production and a decrease in total born piglets in next litter compared with parity 2 to 4 sows, which could be explained by a relatively higher proportion of their body reserves being mobilized compared with multiparous sows. The ADG of the litter was positively related by ADFI of the sows, litter size and BW loss and increasing the ADFI with 1 kg/day throughout lactation likely increased the ADG of the litter with 220 to 440 g/day in parity 1 to 4, respectively. Increasing the ADFI by 1 kg/day reduced the BW loss with 6.6 to 13.9 kg of parity 1 to 4 sows, respectively, during lactation, whereas increasing the average milk yield with 1 kg/day raised the BW loss with 4.3 to 21.0 kg of the four parities during lactation. The number of total born piglets in the next litter was positively related to the number of piglets born in the previous litter. In conclusion, both a high feed intake and a high mobilization of body reserves was a prerequisite for a high milk production. The sows might be very close to the physical limit of what they can ingest and future research should therefore, focus on optimizing the dietary energy and nutrient concentrations of diets for lactating hyper-prolific sows and herein distinguish between primiparous and multiparous sows.     

Multi-stage high cell continuous fermentation for high productivity and titer

We carried out the first simulation on multi-stage continuous high cell density culture (MSC-HCDC) to show that the MSC-HCDC can achieve batch/fed-batch product titer with much higher productivity to the fed-batch productivity using published fermentation kinetics of lactic acid, penicillin and ethanol. The system under consideration consists of n-serially connected continuous stirred-tank reactors (CSTRs) with either hollow fiber cell recycling or cell immobilization for high cell-density culture. In each CSTR substrate supply and product removal are possible. Penicillin production is severely limited by glucose metabolite repression that requires multi-CSTR glucose feeding. An 8-stage C-HCDC lactic acid fermentation resulted in 212.9 g/L of titer and 10.6 g/L/h of productivity, corresponding to 101 and 429% of the comparable lactic acid fed-batch, respectively. The penicillin production model predicted 149% (0.085 g/L/h) of productivity in 8-stage C-HCDC with 40 g/L of cell density and 289% of productivity (0.165 g/L/h) in 7-stage C-HCDC with 60 g/L of cell density compared with referring batch cultivations. A 2-stage C-HCDC ethanol experimental run showed 107% titer and 257% productivity of the batch system having 88.8 g/L of titer and 3.7 g/L/h of productivity. MSC-HCDC can give much higher productivity than batch/fed-batch system, and yield a several percentage higher titer as well. The productivity ratio of MSC-HCDC over batch/fed-batch system is given as a multiplication of system dilution rate of MSC-HCDC and cycle time of batch/fed-batch system. We suggest MSC-HCDC as a new production platform for various fermentation products including monoclonal antibody.     

Segmentation of stained blood cell images measured at high scanning density with high magnification and high numerical aperture optics

In hematological morphology, it is necessary to resolve and analyze the smallest possible cellular details appearing in the light microscope. A prerequisite for computer-aided analysis of subtle morphological features is measuring the cells at a high scanning density with high magnification and high numerical aperture optics. Contrary to visual observations, the information content in a measured picture can be increased by setting the condensor's numerical aperture (NA) greater than the objective's NA. The complexity and heterogeneity of such cell images necessitate a new segmentation method that conserves the morphological information required in the subsequent image analysis, feature extraction, and cell classification. In our segmentation strategy, characteristic color difference thresholds for each nucleus and cytoplasm are combined with geometric operations, probability functions, and a cell model. All thresholds are repeatedly recalculated during the successive improvements of the image masks. None of the thresholds are fixed. This strategy segments blood cell images containing touching cells and large variations in staining, texture, size, and shape. Biological inconsistencies in the calculated cell masks are eliminated by comparing each mask with the cell model criteria integrated into the entire segmentation process. All 20,000 leukocyte images from 120 smears in our leukemia project were segmented with this method.     

Effects of high glucose and high insulin concentrations on osteoblast function in vitro

Bone disease as a consequence of diabetes mellitus (DM) is not fully understood. The effects of high glucose (30 mM), high insulin (50 nM), or mannitol (30 mM; osmotic control) were evaluated on MC3T3-E1 cells (osteoblasts) in vitro. The mRNA and protein levels of parathyroid hormone (PTH) receptor (PTH1R), collagen I, RANKL, osteoprotegerin (OPG), alkaline phosphatase (ALP), and glucose transporter (GLUT1) were estimated by real-time polymerase chain reaction or Western blotting. The mineralization capacity was analyzed by von Kossa staining. High glucose induced overexpression of RANKL (2×) and OPG (30×), suggesting that RANKL-induced osteoclast activity might not be a dominant mechanism of bone disease in DM, since this increase was followed by increased OPG. Collagen I increased by 12×, indicating an excess of organic matrix production. The expression of ALP decreased by 50 %, indicating a deficit in mineralization capacity, confirmed by von Kossa staining. Mannitol induced similar effects as glucose suggesting that extracellular hyperosmolarity was able to stimulate organic matrix production. GLUT1 expression was not altered, and insulin did not reverse most of the effects of glucose, suggesting that glucose uptake by osteoblasts was not altered by high glucose. The data suggest that the bone fragility typical of DM is not a consequence of excessive bone reabsorption but is instead attributable to a defect in organic matrix mineralization. The heightened increase in OPG versus RANKL might cause a decrease in the bone-remodeling cycle. Osteoblasts appear to be more sensitive to extracellular hypertonicity than to the intracellular metabolic effects of hyperglycemia.