1,720,998 research outputs found
Active rumen bacterial and protozoal communities revealed by rna-based amplicon sequencing on dairy cows fed different diets at three physiological stages
Full text linkSeven Italian Simmental cows were monitored during three different physiological stages, namely late lactation (LL), dry period (DP), and postpartum (PP), to evaluate modifications in their metabolically-active rumen bacterial and protozoal communities using the RNA-based amplicon sequencing method. The bacterial community was dominated by seven phyla: Proteobacteria, Bacteroidetes, Firmicutes, Spirochaetes, Fibrobacteres, Verrucomicrobia, and Tenericutes. The relative abundance of the phylum Proteobacteria decreased from 47.60 to 28.15% from LL to DP and then increased to 33.24% in PP. An opposite pattern in LL, DP, and PP stages was observed for phyla Verrucomicrobia (from 0.96 to 4.30 to 1.69%), Elusimicrobia (from 0.32 to 2.84 to 0.25%), and SR1 (from 0.50 to 2.08 to 0.79%). The relative abundance of families Succinivibrionaceae and Prevotellaceae decreased in the DP, while Ruminococcaceae increased. Bacterial genera Prevotella and Treponema were least abundant in the DP as compared to LL and PP, while Ruminobacter and Succinimonas were most abundant in the DP. The rumen eukaryotic community was dominated by protozoal phylum Ciliophora, which showed a significant decrease in relative abundance from 97.6 to 93.9 to 92.6 in LL, DP, and PP, respectively. In conclusion, the physiological stage-dependent dietary changes resulted in a clear shift in metabolically-active rumen microbial communities
Tempo and mode of evolution of a primate-specific retrotransposon belonging to the LINE 1 family.
No full textL1P_MA2 is a primate-specific subfamily of L1 retrotransposons. The consensus sequence of this element differs from the canonical L1 consensus by the presence of a 3800-bp region in 5' (L1M1_5). Part of this region has been proposed to be involved in a dystrophin mutation affecting the correct splicing of the gene and causing an X-linked dilated cardiomyopathy. In consideration of the potential involvement in splicing regulation of this element and also because of its atypical structure, we investigated its evolutionary history by analyzing the inter- and intraspecific divergence of L1P_MA2 sequences in various species of primates. The resulting phylogenetic trees show long terminal branches and short basal internodes, as expected for a rapid event of diversification that occurred in the past. The phylogenetic analysis and the intraspecific divergence estimates revealed a pattern of evolution for this element similar in all primates with the exception of lemurs, thus suggesting that the major wave of expansion of L1P_MA2 in primate genomes occurred after the divergence between Prosimiae and Anthropoidea. These results clearly indicate that a phylogenetic approach is more appropriate than methods based on sequence data from a single species, when investigating time and mode of evolution of retro-elements
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
Is Bacillus cytotoxicus from edible insects a threat?
Full text linkBacillus cytotoxicus is considered a potential emerging foodborne pathogen that has been under investigation in recent years. Most studies have focused on strains from vegetables, particularly potato products, but there is limited information on strains from other food sources. This study addresses the current research gap by investigating the genomic and phenotypic features of B. cytotoxicus isolated from edible insects. The whole genomes and key phenotypic traits of 20 strains isolated from edible insects were investigated. The comparative genome analysis also included 44 available genomes from other sources to identify possible genetic links and the mosaicism of virulence profiles (VP) and antimicrobial resistance genes (AMR). B. cytotoxicus isolated from edible insects showed marked thermotolerance, when vegetative forms could grow at 50–60 °C and survive at 65 °C and exhibited marked proteolytic activities, even at higher temperatures. The heterogeneous phenotypes observed suggest..
Effect of age on caecal microbiota of broiler chickens fed diets supplemented with sodium butyrate
No full textA total of 768 chicks Ross 308 (half males and half females) were housed in 16 pens (48 animals/pen); half pens received a control diet, the other half the same diet supplemented with 150 mg microencapsulated Na-butyrate/kg diet. Growth performance was monitored until 45 d of age. At 11 d, 24 d, and 35 d of age, 32 animals per age were slaughtered to sample caecal content. Intestinal microbiota was evaluated by sequencing of V3-V4 region
of the rRNA 16S gene using Miseq Illumina. Firmicutes was the most represented phylum, followed by Tenericutes and Proteobacteria; Bacteroidates was the least represented. Out of classes, Clostridia was prevalent, followed by Bacilli and Grammaproteobacteria. The dietary Na-butyrate supplementation did not affect performance: final live weight averaged 3294 and 3266 g in the control and supplemented group, respectively, corresponding to 113 and 112 g/d feed intake, and 1.44 and 1.43 feed conversion ratio. The dietary treatment did not affect the composition or abundance neither the diversity of gut microbiota. Only some OTUs (26) had different distributions according to dietary treatment (P<0.05): some, mostly belonging
to Firmicutes phylum and to Clostridiales order, were more abundant in samples from birds fed the control diet; others, such as Tenericutes of the RF39 order, were more present in samples from chickens supplemented with Na-butyrate. On the other hand, microbiota composition significantly changed with age (P=0.001). Among phyla, Proteobacteria and Firmicutes decreased as age increased, whereas Tenericutes increased from 11 to 24 d of age.
Among classes, Mollicutes, X4C0d2, Bacterioidia, and Clostridia increased, whereas Grammaproteobacteria decreased with age. Among orders, Lactobacillales, Enterobacteriales, Erysipelotrichales, burkholderiales, Oceanospirillales, Alteromonadales, Pseudomonadales, Pasteurellales, and Unclassified beta Proteobacteria decreased. The biodiversity in each sample and among samples tended to decrease when age increased. The
effect on biodiversity among samples was evident using both qualitative analysis (that considers presence/absence of sequences and phylogenetic distances) and quantitative analysis (that considers only sequence abundance). The results of the present study indicate that Na-supplementation did not affect caecal microbiota. On the other hand, bacterial groups of gut community decreased with age and the community became more similar among
samples
Evaluating Escherichia coli contamination in bivalve mollusks using the impedance method: a comparison with most probable number analyses and correlation with environmental parameters
Full text linkThe application of an electrochemical (impedance) tool for monitoring Escherichia coli contamination in shellfish was evaluated after 13 months of observation. The primary aim of the present study was to compare the standard most probable number (MPN) and mu-trac 4200 (log imped/100 g) for the assessment of E. coli contamination (log MPN/100 g) in non-depurated bivalve mollusks (BM) from five sampling areas of the Veneto-Emilian coast (Italy) (118 samples). The secondary aim was to evaluate the correlation between E. coli concentrations in BM and environmental factors on a large data set (690). The methods showed a moderate, positive correlation (0.60 and 0.69 Pearson and Spearman coefficients, respectively; P 4,600 MPN/100 g). The results highlighted the suitability of the impedance method for a faster evaluation and routine use especially in clams, while in Mytilus it seemed less effective. Different models built by multivariate permutational variance analysis and multinomial logistic regression selected the suitable environmental features able to predict the E. coli load. Overall, salinity and season affected the E. coli contamination, whereas locally it was mainly influenced by hydrometry and salinity. The application of the impedance method coupled with environmental data analysis could help purification phase management to adhere to legal limits and could represent an advantage for local control authorities to define actions, considering extreme meteorological events' effects as a proactive reaction to climate change
A preliminary study to evaluate a functional genomic approach to monitor microbial communities during cheese ripening
No full text
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
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