双歧啤酒对常见病原菌的拮抗作用

目的了解双歧啤酒对常见病原菌的拮抗效果及影响因素。方法采用纸片扩散法（K-B法）、琼脂打孔法和试管稀释法（MIC法）测定双歧啤酒及其处理物（加热、不同pH）对常见病原菌的抑菌作用,同时用某市售啤酒作为对照。结果双歧啤酒及其处理物均具有一定的抑菌活性。结论双歧啤酒对常见病原菌有一定的抑菌作用,抑菌活性强于市售啤酒。     

双歧啤酒预防性减肥作用的实验研究

目的探讨双歧啤酒预防大鼠肥胖的作用及其对大鼠血脂、瘦素和胰岛素的影响。方法48只SD大鼠被随机分成双歧啤酒低剂量组[12．5ml／（kg·BW）]、中剂量组[25ml／（kg·BW）]、高剂量组[50ml／（kg·BW）]和市售啤酒组[25ml／（kg·BW）]、肥胖模型组以及基础组,进行预防性减肥实验,观察双歧啤酒在大鼠致肥过程中对大鼠的影响,测定指标包括大鼠体重、体脂、脂肪细胞直径、血脂水平和血瘦素、血胰岛素。结果实验结果显示,双歧啤酒各组除TCHO外的所有测定指标值都较肥胖组有明显好转,特别是腹膜下脂肪重量、TG和HDL水平都与正常组差异无显著性,低、中剂量组脂肪细胞直径也与正常组差异无显著性。市售啤酒组所有指标均与肥胖模型组差异无显著性。结论双歧啤酒能有效预防血TG的升高,有效预防啤酒肚的形成。对于预防体脂和体重的增加也有一定作用。     

衰老能延缓吗？

衰老是生命的基本现象。纵观古今中外，无论帝王将相、骚人墨客，还是凡夫俗子，概莫能外。既求长生，又求不老，两者岂能兼得？难乎哉!白居易的乐府说出了这种尴尬：“生若不足恋，老也何足悲。生若苟可恋，老即多生时。不老即须天，不天即须衰。既衰胜早天，此理决不疑。”他劝大家宁可忍受衰老，也切莫早天，说白了不就是好死不如赖活吗!但今非昔比，科学的进步使人不满足于赖活，难道我们就找不到让人既活得好，又活得长的办法吗？     

人体衰老与延缓衰老

<正>衰老是自然规律[1],是人体在生长发育达到成熟后,生理结构和功能等所表现的一系列退行性变化[2],但衰老是可以延缓的。现就人体衰老的原因及延缓衰老的对策简述如下。1机体细胞学的分裂传代生物的寿命是靠组织细胞分裂传代(衰老的细胞由分裂新生成熟所代替),但每传一代的线粒体都比原来短(端粒酶),当短到不能计数生命就停止。人体可分裂传代的组织     

延缓衰老有办法

尽管人类不可避免地会死亡,但是未来人类的衰老过程却有办法变慢,寿命也会明显延长。科学家们对人类衰老的生物、化学过程提出了新的解释,为延年益寿药物的问世敞开了大门。虽然他们的研究方法不是完全相同,但有一个共同的认识:人类的寿命并不是固定不变的。     

益智仁对多刺裸腹蚤的生物学效应--一种延缓衰老药物的筛选实验

以多刺裸腹蚤为动物筛选模型,从药效学方面研究了益智仁提取液对多刺裸腹蚤的生命力和寿命的影响。实验结果表明：0.25％的益智仁提取液使多刺裸腹蚤的体长增加为2．37mm;产仔时间提前了2天;繁殖代数为12代;平均寿命延长了71.11％。充分显示出益智仁对多刺裸腹蚤的生长发育、繁殖和寿命方面都有较为显著的促进作用。     

褪黑素延缓哺乳动物衰老的作用及其机制的研究进展

褪黑素(melatonin)在哺乳动物中是主要由松果体分泌的一种多功能吲哚激素,具有抗氧化、调节睡眠、调节昼夜节律、增强免疫力、抑制肿瘤等作用,在哺乳动物的复杂衰老进程中发挥重要作用。本文从氧化应激和能量代谢两个方面综述了褪黑素在哺乳动物中延缓衰老的作用机制。褪黑素通过清除自由基、激发抗氧化作用以及保护线粒体功能从而减缓氧化应激;通过调节代谢感知、重建昼夜节律以及促进能量消耗调节能量代谢。最后对该领域今后可能的发展方向进行了展望。     

植物叶片衰老及其延缓的分子途径

综述了植物叶片衰老过程中基因表达的上调和下调两种趋势,以及与转ｉｐｔ基因研究有关的问题：（１）ＣＴＫ／ＩＡＡ平衡;（２）形态发育;（３）抗衰老作用;（４）启动子选择等。     

水杨酸延缓离体爬山虎叶片衰老的作用

爬山虎是修饰藤架和墙体的绿化垂体观赏植物,延缓爬山虎叶片衰老可延长爬山虎绿叶的观赏期.本文探讨了水杨酸(salicylic acid,SA)延缓叶片衰老的作用.     

果蝇衰老的调控机制

衰老是一个复杂的生物学过程,涉及到有害物质的积累导致整体生命功能的下降,生物的生理状况逐渐恶化,最终导致疾病和死亡。黑腹果蝇Drosophila melanogaster作为最重要的遗传学工具之一,近年来常被用于衰老的研究,以阐明衰老的发生与发展机制。本文结合本实验室的研究进展,综述了果蝇寿命调控的生理生化机制,如保幼激素、胰岛素/类胰岛素生长因子、TOR信号网络、腺苷酸活化蛋白激酶信号通路、热量限制和饮食限制、氧化应激、小分子RNA以及鞘脂类代谢都会对果蝇的寿命产生影响。除此之外,基因调控网络研究还能够发现潜在的与长寿相关的基因组区域,将有可能发现更多寿命相关基因。以果蝇为模式生物的研究,对于其他昆虫衰老、存活等种群生物学问题的研究以及天敌、益虫保育和害虫控制,具有十分重要的指导意义。     

Pupation in drosophila melanogaster and the effect of the Lethalcryptocephal mutation

The events of normal pupation in Drosophila melanogaster are described in detail from the time of gas bubble expulsion until the completion of pupation with the eversion of the cephalic complex. The importance of the internal gas bubble for posterior movement of the prepupa is examined and its relation to the expulsion of the larval mouthparts and the creation of the anterior gas space described. The phenotype of lethalcryptocephal homozygotes, which characteristically cannot evert their heads, is re-examined. Observations of larval lethality and multiple mouthparts in 1 (2)crc larvae and pupae are described. These new aspects of the mutant phenotype are discussed with respect to the abnormalities of pupation. Fristrom's hypothesis that the basic mutant lesion is an increased stiffness of the pupal cuticle due to an excess chitin deposition is re-evaluated.     

The effect of milling parameters on starch hydrolysis of milled malt in the brewing process

The effect of milling parameters on the hydrolysis of starch during the mashing process was investigated. Hammer milling was compared against roll milling. Roll gap settings, roll speed, speed differential were also analysed, as well as comparing four- to six-roll milling. The parameter of differential speed was also studied through grist particle size distribution. Employing a 65 °C infusion type mashing process for the wort, the glucose and maltose concentrations of malts milled in different ways were analysed. Results showed that the glucose concentration in the wort after 45 min of mashing, obtained using a hammer mill, was the same as that achieved from roll milling in 60 min. For roller mill gap settings the 0.8 mm gap grist required 60 min of mashing to reach a glucose concentration of 3.46 g l⁻¹, whereas the 0.1 mm gap grist achieved the same level of starch hydrolysis in almost half the time, around 30–35 min of mashing. The results regarding roll speed showed that the 300 and 700 rpm mashes required roughly 50 and 40 min, respectively. Comparable sugar concentrations in the 50 rpm mash were obtained in 60 min. Finally, the comparison between simulated four- and six-roll milling showed the latter yielded higher glucose concentrations.     

影响野生型Canton S果蝇睡眠时间的相关生理因素

目的探讨影响果蝇睡眠时间的相关生理因素。方法选择野生型CantonS果蝇为实验对象,利用果蝇活动监测系统(DAMS),以5min为单位自动统计一次果蝇活动次数,若5min内活动次数为零,认为果蝇处于睡眠状态,计为果蝇的睡眠时间,累积计算果蝇24h睡眠总时间为指标,分别观察了日龄(7日龄)相同,而性别不同和性别(雌性)相同,而日龄(2,7,12,17,22,27和32日龄)不同果蝇的24h睡眠总时间。结果①同一日龄(7日龄)不同性别的果蝇之间白天(12h)及夜间(12h)平均睡眠时间的长短存在着显著差异。雌果蝇白天(12h)平均睡眠时间短于雄果蝇,而夜间(12h)平均睡眠时间长于雄果蝇。雌果蝇白天(12h)平均睡眠时间显著短于夜间平均睡眠时间(P0.05);而雄果蝇白天(12h)平均睡眠时间与夜间(12h)平均睡眠时间基本持平。②同一性别(雌性)不同日龄的果蝇,随着日龄的增加,其白天(12h)平均睡眠时间有逐渐缩短的趋势,27日龄的果蝇睡眠时间减少相对明显,32日龄果蝇的睡眠时间有所恢复,相互之间存在着显著差异(P0.05)。夜间(12h)平均睡眠时间有逐渐延长的趋势,27日龄果蝇的夜间平均睡眠时间有所减少,32日龄果蝇的夜间平均睡眠时间相对有所恢复,相互之间存在着显著差异(P0.05)。结论性别与日龄等生理因素对果蝇24h睡眠时间有显著的影响。     

Biochemical characterization of a lichenase from Penicillium occitanis Pol6 and its potential application in the brewing industry

The purification and characterization of an extracellular lichenase from the fungus Penicillium occitanis Pol6 were studied. The strain produced the maximum level of extracellular lichenase (45 ± 5 U ml⁻¹) when grown in a medium containing oat flour (2%, w/v) at 30 °C for 7 days. The purified enzyme EG_L showed as a single protein band on SDS–PAGE with a molecular mass of 20 kDa. Its N-terminal sequence of 10 amino acid residues was determined as LDNGAPLLNV. The purified enzyme showed an optimum activity at pH 3.0 and 50–60 °C. The half-lives of EG_L at 60 °C and 70 °C were 80 min and 21 min, respectively. Substrate specificity studies revealed that the enzyme is a true β-1,3-1,4-d-glucanase. The enzyme hydrolyzed lichenan to yield trisaccharide, and tetrasaccharide as the main products. Under simulated mashing conditions, addition of EG_L (20 U/ml) or a commercial β-glucanase (20 U/ml) reduced the filtration time (25% and 21.3%, respectively) and viscosity (10% and 8.18%, respectively). These characteristics indicate that EG_L is a good candidate in the malting and brewing industry.     

Concurrent purification and antioxidant activity of phycobiliproteins from Lyngbya sp. A09DM: An antioxidant and anti-aging potential of phycoerythrin in Caenorhabditis elegans

The present study probes into the purification of phycobiliproteins, and characterization of their in vitro anti-oxidant activity. Moreover, the study also demonstrates the use of antioxidant virtue of phycoerythrin in moderating the phenomenon of aging in Caenorhabditis elegans. Phycoerythrin, phycocyanin and allophycocyanin were purified successfully from Lyngbya sp. A09DM by ammonium sulfate fractionation appended with Triton X-100 intercession. The success of protocol was examined by a series of biochemical characterization like SDS-PAGE, native-PAGE, UV–visible spectroscopy and fluorescence spectroscopy ensuring purity, integrity and functionality of purified phycoerythrin, phycocyanin and allophycocyanin. Purified phycobiliproteins were evaluated for antioxidant and metal ion chelating activity by various in vitro antioxidant assay systems. Results showed significant and dose-dependent antioxidant as well as metal chelating potential of all phycobiliproteins in decreasing order of phycoerythrin > phycocyanin > allophycocyanin. Expansion in lifespan and improvement in pharyngeal pumping of C. elegans were noticed upon pre-treatment with phycoerythrin (100 μg ml⁻¹). Moreover, phycoerythrin mediated increase in worm survival under oxidative stress revealed that the life expansion effect of phycoerythrin on nematode is in part by an action of its antioxidant virtue. These results collectively added up evidence in favor of the ‘free-radical theory of aging’. The present report, for the first time, describes antioxidant potential of phycoerythrin and its use in extending life-span of C. elegans.     

The effect of the cytochrome P-450 system inducers on the development of drosophila melanogaster

D. melanogaster development was markedly retarded and its survival decreased by larvae treatment with compounds being strong inducers of the cytochrome P-450 2B in mammals— phenobarbital (PB^*), perfluorodecaline (PFD), transstilbene oxide (TSO), and triphenyldioxane (TPD). At the same time, the weak inducer hexobarbital or the selective cytochrome P-450 inducer in mice but not in rats 1,4-bis[2-(dichloropyridyl-oxy)]-benzene (DPB) did not affect the larvae development. The cytochrome P-450 1A1 inducers benzo(a)anthracene (BA) and β-naphtoflavone (BNF) were also not effective. The toxicity of phenobarbital was shown to be decreased by the cytochrome P-450 inhibitor piperonyl butoxide by adding 20-hydroxyecdysone or by treatment with aminophylline—the indirect enhancer of ecdysone production in the larval prothoracic gland. The hypothesis of the moulting hormone degradation as the cause of elevated larvae mortality resulting from the induced high mixed function oxidase activity has been discussed.     

A novel thermophilic xylanase from Achaetomium sp. Xz-8 with high catalytic efficiency and application potentials in the brewing and other industries

Thermophilic xylanases are of great interest for their wide industrial application prospects. Here we identified a thermophilic xylanase (XynC01) of glycoside hydrolase (GH) family 10 in a thermophilic fungal strain Achaetomium sp. Xz-8. The deduced amino acids of XynC01 showed the highest identity of ≤52% to experimentally verified xylanases. XynC01 was functionally expressed in Pichia pastoris, showed optimal activity at pH 5.5 and 75 °C with stability over a broad pH range (pH 4.0–10.0) and at temperatures of 55 °C and below. XynC01 had the highest catalytic efficiency (k_cat/K_m, 3710 mL/s/mg) ever reported for all GH 10 xylanases, and was resistant to all tested metal ions and chemical reagents. Its hydrolysis products of various xylans were simple, mainly consisting of xylobiose and xylose. Under simulated mashing conditions, XynC01 alone had a comparable effect on filtration improvement with Ultraflo from Novozymes (20.24% vs. 20.71%), and showed better performance when combined with a commercial β-glucanase (38.50%). Combining all excellent properties described above, XynC01 may find diverse applications in industrial fields, especially in the brewing industry.     

Protective effect of tetrahydroxystilbene glucoside against d-galactose induced aging process in mice

Tetrahydroxystilbene glucoside (TSG) is a strong antioxidant and free radical scavenger derived from Polygonum multiflorum Thunb. The present study aims to evaluate the protective effect of TSG against d-galactose induced aging process in mice and its possible mechanisms of action. Our study revealed that administration of TSG improved the memory ability and regulated the body weight of mice. TSG also reduced the levels of ROS, NO and IGF-1 and increased the levels of SOD, Ca²⁺ and Klotho protein in the serum. Furthermore, TSG up-regulated the expression of Klotho protein in cerebrum, heart, kidney, testis and epididymis tissues of d-galactose induced aging mice. These results suggested that TSG had a promising anti-aging effect by regulating Klotho gene.     

The impact of brewing yeast cell age on fermentation performance,attenuation and flocculation

Individual cells of the yeast Saccharomyces cerevisiae exhibit a finite replicative lifespan, which is widely believed to be a function of the number of divisions undertaken. As a consequence of ageing, yeast cells undergo constant modifications in terms of physiology, morphology and gene expression. Such characteristics play an important role in the performance of yeast during alcoholic beverage production, influencing sugar uptake, alcohol and flavour production and also the flocculation properties of the yeast strain. However, although yeast fermentation performance is strongly influenced by the condition of the yeast culture employed, until recently cell age has not been considered to be important to the process. In order to ascertain the effect of replicative cell age on fermentation performance, age synchronised populations of a lager strain were prepared using sedimentation through sucrose gradients. Each age fraction was analysed for the ability to utilise fermentable sugars and the capacity to flocculate. In addition cell wall properties associated with flocculation were determined for cells within each age fraction. Aged cells were observed to ferment more efficiently and at a higher rate than mixed aged or virgin cell cultures. Additionally, the flocculation potential and cell surface hydrophobicity of cells was observed to increase in conjunction with cell age. The mechanism of ageing and senescence in brewing yeast is a complex process, however here we demonstrate the impact of yeast cell ageing on fermentation performance.