灌喂植物乳杆菌和干酪乳杆菌增加仔猪肠道菌群多样性及短链脂肪酸生成

【目的】研究断奶前给仔猪饲喂植物乳杆菌和干酪乳杆菌对断奶前、后肠道菌群组成、数量和短链脂肪酸(SCFA)浓度的影响,分析仔猪生长性能与肠道形态、微生物菌群及SCFAs的相关性,探讨测试菌株缓解仔猪断奶应激的可能机制。【方法】选取15窝7 d龄杜长大仔猪,随机分为3组,分别灌喂2 mL去离子水(对照组)、0.5×10~9 CFU/mL植物乳杆菌(LP组)或干酪乳杆菌(LC组)的菌液,每组以窝为单位5个重复,于21 d(断奶)、24 d和35 d屠宰,采集回肠和结肠食糜,分析菌群组成和数量的变化,测定SCFAs浓度。【结果】测试菌株均能显著提高断奶2周后回肠、结肠菌群多样性(P0.05),促进乳酸杆菌和双歧杆菌增殖;显著促进断奶前回肠和结肠中乙酸、丙酸、丁酸和总SCFA生成,促进断奶后乙酸和总SCFA产生;相关分析显示,测试菌株组仔猪腹泻率下降与SCFAs浓度上升、回肠绒毛高度增加和总菌数量上升显著相关,日增重提高与结肠乙酸和TSCFA浓度增加显著相关。【结论】测试菌株促进乳酸杆菌、双歧杆菌等有益菌增殖,增加肠道菌群多样性,促进肠道SCFAs生成。     

饲喂肉杆菌Hg4-03对贡嘎蝠蛾幼虫肠菌生物多样性的影响

【目的】研究贡嘎蝠蛾幼虫肠道优势菌肉杆菌(Carnobacterium sp.)Hg4-03作为食物添加剂对实验室饲养的4龄贡嘎蝠蛾幼虫肠道菌群的影响。【方法】采用16S rDNA序列与PCR/DGGE(Denaturing gradient gel electrophoresis)分析技术相结合的方法,健康幼虫被随机分为处理组1、处理组2和对照组,两组处理组分别饲喂添加不同浓度肉杆菌Hg4-03的天然饲料,对照组只饲喂天然饲料。14 d和28 d后每组随机解剖6条幼虫,收集肠道样品,经细菌通用引物扩增细菌16S rDNA,DGGE分离并进行细菌多样性图谱分析。【结果】饲喂肉杆菌Hg4-03后幼虫肠道菌群的多样性指数呈上升趋势;处理组幼虫肠道中肉杆菌Hg4-03含量增加,且处理组中枯草芽孢杆菌(Bacillus subtilis)的量也明显增加。【结论】将肉杆菌Hg4-03作为益生菌饲喂贡嘎蝠蛾幼虫有助于维持幼虫肠道菌群多样性平衡,这为贡嘎蝠蛾人工或半人工养殖提供了一定的参考价值。     

抗生素和高脂饮食对大鼠肠道乳杆菌多样性的影响

【目的】对正常、高脂、抗生素处理大鼠肠道内乳杆菌进行定性和定量分析,比较不同处理组大鼠肠道乳杆菌的多样性。【方法】应用纯培养和非培养技术(16S r RNA基因序列分析、变性梯度凝胶电泳、实时荧光定量PCR)对大鼠肠道乳杆菌进行分离鉴定和多样性分析。【结果】16S r RNA基因序列同源性分析结果显示,正常组大鼠肠道内分离出的乳杆菌包括约氏乳杆菌(Lactobacillus johnsonii)、鼠乳杆菌(Lactobacillus murinus)、嗜酸乳杆菌(Lactobacillus acidophilus)、罗伊氏乳杆菌(Lactobacillus reuteri)、植物乳杆菌(Lactobacillus plantarum)、肠道乳杆菌(Lactobacillus intestinals)、动物乳杆菌(Lactobacillus animalis)和阴道乳杆菌(Lactobacillus vaginalis);但L.animalis在高脂处理组大鼠肠道内未分离到,L.intestinals和L.vaginalis在抗生素处理组大鼠中未分离到。DGGE结果显示3个组别大鼠肠道中乳杆菌构成差异明显,同一组内样品间相似性较高;相较于正常组和高脂组,抗生素组的丰度较差;且正常组大鼠肠道内乳杆菌的多样性高于高脂组和抗生素组。q-PCR结果显示正常组大鼠肠道乳杆菌的数量明显高于高脂组和抗生素组,高脂组的数量也明显高于抗生素组,且3个组别之间存在显著差异(P0.01)。【结论】高脂饮食及抗生素的使用会减少肠道内乳杆菌多样性。     

罗伊乳杆菌对小鼠血清细胞因子含量和 肠道菌群的影响

目的探讨罗伊乳杆菌对小鼠免疫力及肠道菌群的影响。方法将50只昆明系小鼠按体重随机分成5组:空白对照组、低剂量组、中剂量组、高剂量组和发酵上清液组。空白对照组灌胃等量生理盐水,其余各组分别灌胃罗伊乳杆菌菌液及发酵液上清21d后,眼球取血收集血清,采用ELISA法检测IL-2、IFN-γ、IgA和IgG含量;采用16SrRNA基因高通量测序分析小鼠肠道菌群变化。结果与对照组相比,其余各组小鼠血清IL-2、IFN-γ、IgA和IgG的水平均明显升高,粪便菌群丰度有所增高,多样性降低。与对照组相比,低剂量组和中剂量组小鼠粪便菌群结构无显著差异,而高剂量组和发酵上清液组小鼠粪便菌群结构差异显著。结论罗伊乳杆菌可以增强小鼠免疫力,提高菌群丰度,改变小鼠肠道菌群结构。     

乳腺癌患者抑郁症状与肠道微生物相关性研究

目的 探究乳腺癌患者抑郁症状与肠道微生物的相关性。方法 选取辽宁省肿瘤医院2018年1月至2019年1月诊断及治疗的乳腺癌伴抑郁患者28例,作为抑郁组,同时选取无抑郁的乳腺癌患者28例作为对照组。对两组患者进行肠道微生物检测,使用Pearson模型探究患者肠道微生态特征与抑郁水平的相关性。结果 两组肠道菌群的组成存在一定差异,两组拟杆菌目、肠杆菌科、普氏菌属、克雷伯菌属、链球菌属、埃格特菌属、乳杆菌属、拟杆菌属、帕拉拟杆菌属、瘤胃球菌属的丰度具有差异(P0.05),两组样本菌群多样性具有差异。Pearson相关性分析显示,乳杆菌属与抑郁自评量表(BDI)评分呈显著负相关(r=-0.792,P0.001);拟杆菌目、克雷伯菌属与BDI评分呈显著正相关(r=0.458,0.477,P=0.003,0.002)。结论 乳腺癌患者抑郁症状与肠道菌群中的拟杆菌目、乳杆菌属、克雷伯菌属具有相关性。     

乳杆菌胞外多糖对人体粪便菌群及其产生短链脂肪酸的影响

目的在体外利用7名志愿者的新鲜粪便作为来源,选择菊粉作为对照,研究干酪乳杆菌LC2W与鼠李糖乳杆菌Y37胞外多糖对人体肠道菌群的影响。方法利用PCR-DGGE(变性梯度凝胶电泳)方法分析样品中菌群组成,采用高效液相色谱的方法分析短链脂肪酸组成。结果与菊粉相比,粪便菌群在添加乳杆菌胞外多糖培养后,可以促进短链脂肪酸的生成,保持肠道菌群的多样性。结论干酪乳杆菌LC2W与鼠李糖乳杆菌Y37的胞外多糖在体外有调节粪便菌群的作用。     

肠道菌群与肠易激综合征分型及患者血清细胞间黏附分子 1表达的关系

目的分析肠道菌群与IBS分型及患者血清细胞间黏附分子 1(ICAM 1)表达的关系,为后续研究提供参考。方法选择2018年12月至2020年1月我院收治的152例符合标准的肠易激综合征(IBS)患者作为观察组,并依照罗马Ⅲ标准将观察组患者分为腹泻型组(62例)、便秘型组(56例)、混合型组(34例);选择同期我院健康体检者30例为对照组。检测受试者粪便中双歧杆菌、乳杆菌、肠杆菌和肠球菌数量,同时检测受试者血清ICAM 1水平。采用Pearson相关性分析患者肠道菌群与血清ICAM 1关系,并采用Logistics回归模型分析肠道菌群与IBS各亚型的关系。结果观察组患者血清ICAM 1、肠道双歧杆菌、乳杆菌水平显著低于对照组,肠道肠杆菌和肠球菌水平显著高于对照组,差异均有统计学意义(均P<0.05)。不同亚型IBS患者血清ICAM 1、肠道双歧杆菌、乳杆菌、肠杆菌和肠球菌水平存在明显差异,其中混合组患者血清ICAM 1、肠杆菌、肠球菌数量最高,双歧杆菌、乳杆菌数量最低;腹泻型组肠道肠杆菌、肠球菌数量最低,双歧杆菌、乳杆菌数量最高(均P<0.05)。肠道中双歧杆菌、乳杆菌、肠杆菌、肠球菌数量是IBS分型的独立影响因素(均P<0.05)。患者肠道双歧杆菌、乳杆菌数量与ICAM 1水平呈显著负相关,而肠道肠杆菌和肠球菌数量与ICAM 1水平呈显著正相关(均P<0.05)。结论肠道菌群可影响IBS患者分型,且肠道中部分菌群与ICAM 1水平存在显著相关关系。     

高通量测序分析口服抗生素大鼠肠道菌群组成变化

目的探讨口服抗生素大鼠肠道菌群变化。方法在雄性SD大鼠的饮用水中添加肠道不吸收的抗生素(新霉素、杆菌肽和游霉素),饮用1周后,收集粪便并提取细菌基因组DNA,PCR扩增r DNA的V4区特定序列,用Illumina Mi Seq平台测序,进行生物信息学分析大鼠粪便中肠道菌群的组成。结果与对照组相比,抗生素组样品的菌群多样性显著下降(P0.05)。克雷伯菌属、理研菌科等菌群百分比显著增高,乳杆菌属、拟杆菌目(S24-7)等菌群百分比显著下降。结论饮用抗生素的大鼠肠道菌群有显著变化。     

咖啡摄入量对小鼠肠道微生物及酶活性的影响

目的研究摄入不同咖啡浓度对小鼠酶活性、肠道微生物、体重的影响,从分析肠道四种微生物变化和四种酶的活性变化来讨论摄入咖啡对健康的影响。方法 SPF级昆明小鼠随机分为4组,即低、中、高咖啡浓度组和正常对照组,所有实验组小鼠日常给予蒸馏水饮用,实验低、中、高浓度组每天2次分别灌胃给予0.0045g/mL、0.0090g/mL、0.0180g/mL的咖啡溶液0.4mL/(只·次),对照组给予蒸馏水灌胃,实验时间为1个月,测小鼠体重、肠道微生物和酶活性等指标并进行分析。结果与对照组相比,低浓度咖啡摄入组乳杆菌、双歧杆菌、大肠埃希菌数显著增加(P0.01或P0.05),需氧和厌氧细菌数显著降低(P0.01);中浓度咖啡摄入组乳杆菌、双歧杆菌数显著低于对照组和低浓度组(P0.01),大肠埃希菌显著高于对照组(P0.05);高浓度咖啡摄入组乳杆菌和大肠埃希菌总数显著低于对照组(P0.01或P0.05);低浓度摄入组的木聚糖酶、纤维素酶、淀粉酶、蛋白酶的活性均显著高于(Ps0.01)对照组和中浓度咖啡摄入组;各组小鼠体重差异无统计学意义(P0.05)。结论适当摄入咖啡小鼠肠道双歧杆菌和乳杆菌等益生菌数量增加显著,小鼠肠道中具有代表性的淀粉酶、纤维素酶、蛋白酶、木聚糖酶的活性均显著增加,但咖啡摄入对小鼠体重影响不显著。     

一株植物乳杆菌Lp3对高脂模型大鼠的益生作用

【目的】本研究通过构建大鼠高脂结构模型来探究一株植物乳杆菌Lp3的益生作用。【方法】植物乳杆菌Lp3筛选自青藏高原地区传统发酵的牦牛酸奶,初步认定Lp3是一株具有良好耐受力的降胆固醇菌株,且体外益生特性突出,本研究通过建立高脂SD大鼠模型,在饲喂试验动物高脂饲料的同时灌胃植物乳杆菌Lp3,来确定该菌株对试验动物血脂的影响效果,并同时研究其对大鼠肠道菌群、粪便水分、粪便中胆固醇和胆汁酸含量的影响,以及对肝脏组织中的胆固醇(TC)和甘油三酯(TG)的影响。【结果】结果表明,植物乳杆菌Lp3对大鼠没有任何明显的毒副作用,对高脂模型大鼠具有良好的降血脂效果。饲喂高脂饲料并灌喂乳酸菌Lp3组大鼠(HL)的血清总胆固醇、甘油三酯和低密度脂蛋白胆固醇含量较饲喂高脂饲料组(HC)显著减少(P0.05),但是高密度脂蛋白胆固醇的含量变化并不明显。HC组大鼠与HL组及饲喂普通日粮组(对照组)大鼠相比较,HC组大鼠粪便中大肠杆菌数量明显增加,双歧杆菌、乳杆菌数量明显减少。但是灌胃乳酸菌的HL组大鼠的粪便中乳杆菌数略高于对照组,大肠杆菌和双歧杆菌数量和对照组大鼠的基本一致。表明植物乳杆菌Lp3具有维持肠道菌群平衡的作用。此外灌胃乳酸菌后HL组大鼠粪便含水量比HC组要高6.44%。HC组大鼠肝脏组织中胆固醇和甘油三酯要显著高于HL组(P0.05),说明Lp3可以减少脂类物质在肝脏组织中的沉积。从肝脏组织切片来看,也可以得出上述结论。【结论】结果表明本研究所筛选的植物乳杆菌Lp3对高脂大鼠具有值得深入研究的益生作用。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.     

Chemical constituents from the fruits of Rhus typhina L. and their chemotaxonomic significance

This work describes the isolation and characterization of twenty-nine compounds from the fruits of Rhus typhina L., including eleven flavonoids (1–11), eleven phenols (12–22), two pentacyclic triterpenes (23–24), two organic acids (25–26), one lumichrome (27), one courmarin (28) and one pyrimidine (29) on the basis of their spectroscopic data. Compounds apigenin (1), daidzein (4), orobol (5), 3′, 5, 5′, 7-tetrahydroxyflavanone (6), naringenin (7), butein (8), (-)-catechin (9), quercetin-3-O-α-L-(3″-O-galloyl)-rhamnoside (11), 2-hydroxybenzoic acid (13), 4-hydroxybenzaldehyde (14), vanillin (15), methyl 3,4-dihydroxybenzoate (16), 3,5-dihydroxybenzamide (18), tyrosol (19), caffeic acid (20), 3-(2,4,6-trihydroxyphenyl)-1-(4-hydroxyphenyl)-propan-1-one (21), phlorizin (22), friedelin (23), oleanolic acid (24), 4,4-dimethyl-heptanedioic acid (25), anthranilic acid (26), lumichrome (27), scoparone (28) and uracil (29) have not been recorded before in this plant. This is the first report on the occurrence of compounds 4–7, 9, 11, 13–14, 16, 18–21, 25–29 from the genus Rhus. Moreover, the chemotaxonomic significance of these isolated compounds was also summarized.