食物氧化蛋白对小鼠肠道菌群及氧化还原状态的影响

目的研究摄食不同方式氧化酪蛋白对小鼠肠道菌群和氧化还原状态的影响。方法分别以H2O2/Cu2+、HClO处理酪蛋白,丙二醛(MDA)处理酪蛋白、大豆蛋白。雄性KM小鼠分为6组:酪蛋白组,H2O2-Cu2+氧化酪蛋白组,HClO氧化酪蛋白组,MDA氧化酪蛋白组,大豆蛋白组和MDA氧化大豆蛋白组,饲喂10周。结果酪蛋白和大豆蛋白经氧化处理后羰基含量显著上升(P0.05),体外消化率下降。饲喂氧化蛋白饲粮的小鼠结肠内容物乳杆菌数量均显著低于对照组(P0.05);HClO和MDA氧化酪蛋白组大肠埃希菌、肠球菌数量显著高于对照组(P0.05),MDA氧化大豆蛋白组大肠埃希菌数量显著高于对照组(P0.05)。氧化蛋白处理引起小鼠结肠组织MDA上升,其中MDA氧化蛋白处理达显著水平(P0.05);结肠过氧化氢酶(CAT)活力上升,其中H2O2/Cu2+和MDA氧化蛋白组达显著水平(P0.05);H2O2/Cu2+氧化酪蛋白处理引起结肠GSH-Px显著升高(P0.05);氧化蛋白引起结肠总抗氧化能力(T-AOC)下降,其中H2O2/Cu2+、HClO氧化酪蛋白和MDA氧化大豆蛋白处理达显著水平(P0.05)。蛋白质体外消化率与结肠肠球菌呈负相关(R=-0.81,P=0.051);蛋白羰基含量与结肠乳杆菌呈显著负相关(R=-0.94,P0.01);大肠埃希菌(R=0.93,P0.01)和肠球菌(R=0.85,P0.05)分别与蛋白羰基含量呈正相关。结论氧化后蛋白消化率降低、羰基含量增高,导致肠道乳杆菌减少,大肠埃希菌和肠球菌上升;结肠黏膜脂质过氧化,氧化损伤程度与蛋白氧化处理方式有关。     

放化疗对胃肠道的损伤以及微生态制剂防治的研究进展

肿瘤患者放化疗后不良反应较多,尤其是胃肠道反应.放化疗对胃肠道的损伤主要包括:严重损伤肠粘膜,造成肠黏膜免疫功能紊乱,以及肠道菌群失调,引发腹泻或便秘.研究发现,微生态制剂可用于防治放化疗对胃肠道的损伤,减少或避免不良反应的发生.     

焦米对番泻叶所致腹泻小鼠的止泻及肠道菌群影响研究

目的考察焦米水对肠道菌群失调性腹泻的调节作用。方法将小鼠分为5组,分别为模型组、正常组和生米组、焦米组、自由恢复组三组实验组,除正常组外,用番泻叶水煎液给小鼠灌胃连续6 d造成小鼠腹泻模型,实验组分别给予生米、焦米及生理盐水作为自由恢复组,每天观察各组小鼠腹泻情况,并且于第2天、第6天取小鼠粪便进行肠道菌群检测,并做菌群计数,数据进行统计学处理。结果成功建立了小鼠肠道菌群失调腹泻模型,焦米组小鼠腹泻较生米组和自由恢复组恢复较快,差异有统计学意义（P〈0.05）。给予生米、焦米的小鼠肠道菌群恢复较快,与自由恢复组相比差异有统计学意义（P〈0.05）,焦米组与生米组相比菌群有一定的提高,但差异无统计学意义（P〉0.05）。结论焦米水能明显的改善小鼠的腹泻症状,焦米有一定的提高小鼠肠道菌群,改善小鼠肠道菌群环境的作用。焦米与生米相比对腹泻小鼠的恢复促进调节作用更好,可能跟米炒焦后所生成的新物质有关。     

肠道菌群变化对实验小鼠肠黏膜免疫的影响

目的探讨肠道菌群变化对肠黏膜相关淋巴组织的影响。方法通过变性梯度凝胶电泳（Denatu-ring gradient gel electrophoresis,DGGE）法研究了三种不同级别实验小鼠即清洁级小鼠、SPF小鼠和普通小鼠肠道菌群的组成,并用免疫组织化学（immunohistochemistry,IHC）方法研究了此三种不同级别的实验小鼠肠黏膜相关淋巴组织sIgA阳性细胞分布情况。结果普通小鼠肠道细菌种类最多,其sIgA阳性细胞分布最多,肠道不同部位之间sIgA分布情况差异有显著性（P〈0.05）,小肠和大肠之间的阳性细胞分布差异极显著（P〈0.01）;其次是清洁级小鼠,其肠道不同部位之间菌种组成差异无显著性,小肠和大肠之间的阳性细胞分布差异有显著性（P〈0.05）;SPF小鼠肠道细菌种类最少,故其sIgA阳性细胞分布最少,且其肠道不同部位之间菌种组成差异无显著性,小肠和大肠之间的阳性细胞分布差异无显著性（P〉0.05）。结论随着动物微生物控制级别的增高,肠道微生物多样性递减;sIgA阳性细胞与肠道细菌种类正相关。     

Tree litter and forest understorey vegetation: a conceptual framework to understand the effects of tree litter on a perennial geophyte, Anemone nemorosa

Background and Aims

Litter is a key factor in structuring plant populations, through positive or negative interactions. The litter layer forms a mechanical barrier that is often strongly selective against individuals lacking hypocotyle plasticity. Litter composition also interacts with plant growth by providing beneficial nutrients or, inversely, by allowing harmful allelopathic leaching. As conspicuous litter fall accumulation is often observed under deciduous forests, interactions between tree litter and understorey plant populations are worthy of study.

Methods

In a 1-year ex-situ experiment, the effects of tree litter on the growth of Anemone nemorosa, a small perennial forest geophyte, were investigated. Three ‘litter quantity’ treatments were defined, representative of forest floor litter (199, 356·5 and 514 g m⁻²), which were crossed with five ‘litter composition’ treatments (Quercus petraea, Fagus sylvatica, Carpinus betulus, Q. petraea + F. sylvatica and Q. petraea + C. betulus), plus a no-litter control. Path analysis was then used to investigate the pathways linking litter characteristics and components of adult plant growth.

Key Results

As expected, the heavier the litter, the longer the petiole; rhizome growth, however, was not depreciated by the litter-induced petiole lengthening. Both rhizome mass increment and number of initiated buds marginally increased with the amount of litter. Rhizome mass increment was in fact determined primarily by leaf area and leaf life span, neither of which was unequivocally correlated with any litter characteristics. However, the presence of litter significantly increased leafing success: following a late frost event, control rhizomes growing in the absence of litter experienced higher leaf mortality before leaf unfolding.

Conclusions

The study questions the role of litter as a physical or chemical barrier to ground vegetation; to better understand this role, there is a need for ex-situ, longer-term experiments coupled with in-situ observations in the forest.     

Intravaginal sponges to synchronize estrus decrease sexual attractiveness in ewes

Vaginal secretions are an important source of chemical signals, which affect ewes' attractiveness. Moreover, alterations of vaginal flora reduce sexual attractiveness of estrous ewes. As intravaginal sponges containing progestagens (widely used for estrous synchronization) affect vaginal flora, our aims were to determine if estrous ewes pretreated with intravaginal sponges were less attractive than ewes displaying spontaneous estrus, and if the addition of antibiotic to the sponge mitigated the decreased sexual attractiveness. Seventy-two estrous ewes were used in experiment 1: in 36, estrus was synchronized with commercial intravaginal sponges (50 mg medroxyprogesterone acetate for 14 days, group MAP1), whereas the other 36 were given a PGF2α analogue 19 to 20 days earlier and displayed spontaneous estrus (group C1). In experiment 2, 72 ewes were treated with intravaginal sponges for 14 days; for 36 ewes, the sponges contained 0.02 mg oxytetracycline (group Ox), whereas there was no antibiotic in the sponges for the remaining 36 ewes (group MAP2). In both experiments, sexual attractiveness was determined in 12 groups of six estrous ewes (three MAP1 vs. three C1, and three MAP2 vs. three Ox for Experiments 1 and 2, respectively) located in a 4 × 4 m pen. Courting and mating time that each ram spent with each ewe was recorded. After 5 min, the ewe with which the ram spent more time (most attractive ewe, ranked one, scale one to six) was taken out from the pen. The procedure was repeated until the ram ranked all six ewes, and repeated in the 12 groups in both experiments. In experiment 1, C1 ewes were more attractive than MAP1 ewes (ranks: 2.9 ± 0.3 vs. 4.1 ± 0.3, mean ± SEM, respectively; P < 0.002). In experiment 2, sexual attractiveness of MAP2 and Ox ewes was similar (3.5 ± 0.3 vs. 3.4 ± 0.3, respectively). We concluded that the use of intravaginal sponges impregnated with medroxyprogesterone acetate negatively affected ewes' sexual attractiveness, but this decrease was not mitigated by inclusion of a local antibiotic.     

A maximum likelihood approach to generate hypotheses on the evolution and historical biogeography in the Lower Volga Valley regions (southwest Russia)

The evolution of the diverse flora in the Lower Volga Valley (LVV) (southwest Russia) is complex due to the composite geomorphology and tectonic history of the Caspian Sea and adjacent areas. In the absence of phylogenetic studies and temporal information, we implemented a maximum likelihood (ML) approach and stochastic character mapping reconstruction aiming at recovering historical signals from species occurrence data. A taxon-area matrix of 13 floristic areas and 1018 extant species was constructed and analyzed with RAxML and Mesquite. Additionally, we simulated scenarios with numbers of hypothetical extinct taxa from an unknown palaeoflora that occupied the areas before the dramatic transgression and regression events that have occurred from the Pleistocene to the present day. The flora occurring strictly along the river valley and delta appear to be younger than that of adjacent steppes and desert-like regions, regardless of the chronology of transgression and regression events that led to the geomorphological formation of the LVV. This result is also supported when hypothetical extinct taxa are included in the analyses. The history of each species was inferred by using a stochastic character mapping reconstruction method as implemented in Mesquite. Individual histories appear to be independent from one another and have been shaped by repeated dispersal and extinction events. These reconstructions provide testable hypotheses for more in-depth investigations of their population structure and dynamics.     

iFlora与植物志修订的若干思考——以杜鹃花科白珠树属为例

结合现代植物学、DNA测序与信息等关键技术而产生的新一代智能植物志（iFlora）,其研发中最首要和迫切的任务之一就是如何将前沿、准确和完善的植物数据信息进行特色整合及智能化处理,为用户提供一个客观而科学的,具理论和实际应用为一体的植物学知识共享平台,并有效地为国民经济发展提供有价值的植物资源信息渠道。本文简要介绍了与传统植物志和目前常用的电子植物志数据库相区别的iFlora数据信息的分级内容、特点和功能,并强调了作为iFlora的核心数据信息,即用于物种鉴定的植物DNA条形码、关键形态学分类特征、植物图像等识别数据,以及分子系统发育数据等。以杜鹃花科（Ericaceae）白珠树属（Gaultheria）和其属下红粉白珠（G.hookeri）为例,介绍了iFlora采用的三类数据（核心数据、基础数据和拓展数据）构成的三级信息及其功能,同时探讨了信息整合时可能遇到的问题。     

Phylogenetic systematics of Sternbergia (Amaryllidaceae) based on plastid and ITS sequence data

The phylogenetics of Sternbergia (Amaryllidaceae) were studied using DNA sequences of the plastid ndhF and matK genes and nuclear internal transcribed spacer (ITS) ribosomal region for 38, 37 and 32 ingroup and outgroup accessions, respectively. All members of Sternbergia were represented by at least one accession, except S. minoica and S. schubertii, with additional taxa from Narcissus and Pancratium serving as principal outgroups. Sternbergia was resolved and supported as sister to Narcissus and composed of two primary subclades: S. colchiciflora sister to S. vernalis, S. candida and S. clusiana, with this clade in turn sister to S. lutea and its allies in both Bayesian and bootstrap analyses. A clear relationship between the two vernal flowering members of the genus was recovered, supporting the hypothesis of a single origin of vernal flowering in Sternbergia. However, in the S. lutea complex, the DNA markers examined did not offer sufficient resolving power to separate taxa, providing some support for the idea that S. sicula and S. greuteriana are conspecific with S. lutea. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 166 , 149–162.     

Can differential responses to nutrients explain the success of environmental weeds?

Abstract. Question: The use of plant traits to predict weed impact is a long‐standing goal in weed ecology. In particular, trait plasticity, i.e. the variability of a trait response to environmental change, is widely considered to contribute to weed success. However, the generality of the role of trait plasticity in determining weed impacts has never been systematically tested. Methods and location: We tested the hypothesis that high‐impact environmental weeds have greater plasticity in growth responses to nutrient availability than low‐impact species. In a glasshouse experiment, we supplied a complete nutrient solution at five different concentrations to seedlings of 24 species of high‐ and low‐impact environmental weeds from south east Queensland, Australia. Results: Almost all species showed plasticity in biomass accumulation in response to the nutrient treatments, but plasticity in biomass accumulation did not differ between related high‐ and low‐impact species. There was no evidence of nutrient‐related plasticity in root: shoot allocation. Seedling survival was greater at higher nutrient concentrations, and also differed greatly between families. Survival among low‐impact species was marginally (p= 0.0610) lower than among high‐impact species. Conclusion: We conclude that the impact of environmental weeds in south east Queensland cannot be predicted from nutrient‐related plasticity in seedling growth. The effects of nutrients on seedling survival warrant further research.