1,721,151 research outputs found
Composition and antimicrobial properties of Satureia cuneifolia Ten. And Thymbra sintenisii Bornm. Et Aznav. Supsp. Isaurica P. H. Davis essential oils.
No full textResistance to freezing and freeze-drying storage processes of probiotic bifidobacteria.
No full textThe resistance to freezing at –135 °C and freeze-drying of potentially probiotic
bifidobacteria strains isolated from human habitat and from commercial probiotic products
already present in the Italian market were tested. The analysis was conducted in two
different cryoprotectives, sucrose and skim milk. The strains of Bifidobacterium animalis, the only species found in the commercial probiotic product, were resistant to freezing and freeze-drying in both of the cryoprotectives used. Bifidobacteria from human habitat, B 1501 and B 632 Bifidobacterium breve strains and B 600/2, B 669/3 and B 2416 Bifidobacterium catenulatum strains, resulted as the most resistant strains in the storage processes in both cryoprotectives. These strains are potentially useful for industrial applications. In the strains tested the percentage of viable cells were higher after freezing than after freeze drying. The performance of the cryoprotectives analysed were strain-dependent
Validation of candidate reference genes in Bifidobacterium adolescentis for gene expression normalization
No full textNormalization is an essential prerequisite for producing accurate real-time PCR expression analyses. The objective of this study is the selection of a set of optimal reference genes in Bifidobacterium adolescentis gene expression studies under bile exposure. B adolescentis is a particularly abundant species in the human adults gut microbiota, exerting relevant probiotic activities. In the gastrointestinal tract, bile represents a hard challenge for bacterial survival, because of its toxic effect. The natural exposure to bile in the colonic environment induces cells adaptation and tolerance mechanisms in bifidobacteria, which determines changes in gene expression profile, influencing the expression levels of housekeeping genes. In this context, the stability of 9 putative reference genes (cysS, purB, recA, rpoB-L, GADPH-R, 16S rRNA, glnA1, gyrA2, sdhA) was examined in B. adolescentis exposed to bile extract, using two different software (BestKeeper and NormFinder). Both algorithms identified gyrA2 and sdhA as the most stable genes under our experimental conditions, while 16S rRNA is the least reliable HKGs. To our best knowledge, this is the first attempt to validate reference genes in Bifidobacterium spp. and the results offer an appropriate set of reference genes suitable for qRT-PCR studies on B. adolescentis strains under bile stress
Probiotics and Prebiotics for the Health of Companion Animals
No full textCompanion animals, also referred as pets, are animals kept primarily as companions at home or having close daily relationship with humans. Dogs and cats are the major human companions and their health and wellness are essential for pet owners. Ensuring a wholesome and balanced diet is a fundamental duty of a responsible pet owner. In the last decades, the growing knowledge in canine and feline nutrition has greatly contributed to improve longevity and well-being of companion animals and interesting outcomes have been obtained with the introduction of dietary fibres and beneficial microorganisms in pets’ diet
Lactobacillus salivarius and Lactobacillus gasseri down-regulate Aggregatibacter actinomycetemcomitans exotoxins expression
Full text linkBeneficial microbes, such as lactobacilli establish a symbiosis with the host and confer health-associated effects, by limiting the growth of indigenous pathogens and challenging microbes introduced by altered foods. Nevertheless, there is scarce information on the effects of beneficial microbes on the virulence properties of bacterial species associated with oral diseases, such as periodontitis. Aggregatibacter actinomycetemcomitans is a Gram-negative species highly implicated in the etiology of localized aggressive periodontitis. The objective of this study was to investigate the effect of lactobacilli on the expression of the two major virulence factors of A. actinomycetemcomitans. Lactobacillus salivarius and L. gasseri were selected as beneficial species. The gene expressions of leukotoxin (LtxA) and cytolethal distending toxin (CdtB) by A. actinomycetemcomitans were analyzed in response to challenge by lactobacilli cell-free supernatants. Neither lactobacilli affected the growth, but strongly attenuated the expressions of both CdtB and LtxA in the two A. actinomycetemcomitans strains tested. This reduction of the expression of these two exotoxins was time-dependent. These fundamental findings may indicate that lactobacilli can reduce the virulence of putative opportunistic oral pathogens, and may provide insights to future therapeutic approaches for the respective diseases
Bifidobacterium xylocopae sp. nov. and Bifidobacterium aemilianum sp. nov., from the carpenter bee (Xylocopa violacea) digestive tract
Full text linkSocial bees harbor a community of gut mutualistic bacteria, among which bifidobacteria occupy an important niche. Recently, four novel species have been isolated from guts of different bumblebees, thus allowing to suppose that a core bifidobacterial population may be present in wild solitary bees. To date there is sparse information about bifidobacteria in solitary bees such as Xylocopa and Osmia spp., this study is therefore focused on the isolation and characterization of bifidobacterial strains from solitary bees, in particular carpenter bee (Xylocopa violacea), builder bee (Osmia cornuta), and red mason bee (Osmia rufa). Among the isolates from Osmia spp. no new species have been detected whereas among Xylocopa isolates four strains (XV2, XV4, XV10, XV16) belonging to putative new species were found. Isolated strains are Gram-positive, lactate- and acetate-producing and possess the fructose-6-phosphate phosphoketolase enzyme. Full genome sequencing and genome annotation were performed for XV2 and XV10. Phylogenetic relationships were determined using partial and complete 16S rRNA sequences and hsp60 restriction analysis that confirmed the belonging of the new strains to Bifidobacterium genus and the relatedness of the strains XV2 and XV10 with XV16 and XV4, respectively. Phenotypic tests were performed for the proposed type strains, reference strains and their closest neighbor in the phylogenetic tree. The results support the proposal of two novel species Bifidobacterium xylocopae sp. nov. whose type strain is XV2 (=DSM 104955T = LMG 30142T), reference strain XV16 and Bifidobacterium aemilianum sp. nov. whose type strain is XV10 (=DSM 104956T = LMG 30143T), reference strain XV4
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Bifidobacterium aerophilum sp. nov., Bifidobacterium avesanii sp. nov. and Bifidobacterium ramosum sp. nov.: Three novel taxa from the faeces of cotton-top tamarin (Saguinus oedipus L.)
No full textForty-five microorganisms were isolated on bifidobacteria selective medium from one faecal sample of an adult subject of the cotton-top tamarin (Saguinus oedipus L.). All isolates were Gram-positive, catalase-negative, anaerobic, fructose-6-phosphate phosphoketolase positive, and asporogenous rod-shaped bacteria. In this study, only eight out of the forty-five strains were characterized more deeply, whereas the others are still currently under investigation. They were grouped by BOX-PCR into three clusters: Cluster I (TRE 17T, TRE 7, TRE 26, TRE 32, TRE 33, TRE I), Cluster II (TRE CT), and Cluster III (TRE MT). Comparative analysis of 16S rRNA gene sequences confirmed the results from the cluster analysis and revealed relatively low level similarities to each other (mean value 95%) and to members of the genus Bifidobacterium. All eight isolates showed the highest level of 16S rRNA gene sequence similarities with Bifidobacterium scardovii DSM 13734T (mean value 96.6%). Multilocus sequence analysis (MLSA) of five housekeeping genes (hsp60, rpoB, clpC, dnaJ and dnaG) supported their independent phylogenetic position to each other and to related species of Bifidobacterium. The G + C contents were 63.2%, 65.9% and 63.0% for Cluster I, Cluster II and Cluster III, respectively. Peptidoglycan types were A3α l-Lys-l-Thr-l-Ala, A4β l-Orn (Lys)-d-Ser-d-Glu and A3β l-Orn-l-Ser-l-Ala in Clusters I, II and III, respectively. Based on the data provided, each cluster represented a novel taxon for which the names Bifidobacterium aerophilum sp. nov. (TRE 17T = DSM 100689 = JCM 30941; TRE 26 = DSM 100690 = JCM 30942), Bifidobacterium avesanii sp. nov. (TRE CT = DSM 100685 = JCM 30943) and Bifidobacterium ramosum sp. nov. (TRE M = DSM 100688 = JCM 30944) are proposed
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