Transient vitamin B5 starving improves mammalian cell homeostasis and protein production.

Maintaining a metabolic steady state is essential for an organism's fitness and survival when confronted with environmental stress, and metabolic imbalance can be reversed by exposing the organism to fasting. Here, we attempted to apply this physiological principle to mammalian cell cultures to improve cellular fitness and consequently their ability to express recombinant proteins. We showed that transient vitamin B5 deprivation, an essential cofactor of central cellular metabolism, can quickly and irreversibly affect mammalian cell growth and division. A selection method was designed that relies on mammalian cell dependence on vitamin B5 for energy production, using the co-expression of the B5 transporter SLC5A6 and a gene of interest. We demonstrated that vitamin B5 selection persistently activates peroxisome proliferator-activated receptors (PPAR), a family of transcription factors involved in energy homeostasis, thereby altering lipid metabolism, improving cell fitness and therapeutic protein production. Thus, stable PPAR activation may constitute a cellular memory of past deprivation state, providing increased resistance to further potential fasting events. In other words, our results imply that cultured cells, once exposed to metabolic starvation, may display an improved metabolic fitness as compared to non-exposed cells, allowing increased resistance to cellular stress

Bio-coloration of bacterial cellulose assisted by immobilized laccase

In this work a process for the bio-coloration of bacterial cellulose (BC) membranes was developed. Laccase from Myceliophthora thermophila was immobilized onto BC membranes and retained up to 88% of residual activity after immobilization. Four compounds belonging to the flavonoids family were chosen to test the in situ polymerase activity of immobilized laccase. All the flavonoids were successfully polymerized by laccase giving rise to yellow, orange and dark brown oligomers which conferred color to the BC support. The optimal bio-coloration conditions were studied for two of the tested flavonoids, catechol and catechin, by varying the concentration and time of incubation. High color depth and resistance to washing were obtained for both compounds. The highly porous bacterial cellulose material demonstrated great performance as a bio-coloration support, in contrast to other materials cited in literature, like cotton or wool. The process developed is presented as an environmentally friendly alternative for bacterial cellulose bio-coloration and will contribute deeply for the development of new fashionable products within this material.The authors would like to acknowledge Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI‑01‑0145‑FEDER‑006684) and BioTecNorte operation (NORTE‑01‑0145‑FEDER‑000004) funded by Euro‑ pean Regional Development Fund under the scope of Norte2020‑Programa Operacional Regional do Norte. The authors would like also to acknowl‑ edge the Basic Science Research Program through the National Research Foundation of Korea (NRF), which was funded by the Ministry of Education (2017R1D1A1B03031959).info:eu-repo/semantics/publishedVersio

Fine-scale Identification of the Most Likely Source of a Human Plague Infection

We describe an analytic approach to provide fine-scale discrimination among multiple infection source hypotheses. This approach uses mutation-rate data for rapidly evolving multiple locus variable-number tandem repeat loci in probabilistic models to identify the most likely source. We illustrate the utility of this approach using data from a North American human plague investigation

The complete genome sequence and comparative genome analysis of the high pathogenicity Yersinia enterocolitica strain 8081

The human enteropathogen, Yersinia enterocolitica, is a significant link in the range of Yersinia pathologies extending from mild gastroenteritis to bubonic plague. Comparison at the genomic level is a key step in our understanding of the genetic basis for this pathogenicity spectrum. Here we report the genome of Y. enterocolitica strain 8081 (serotype 0:8; biotype 1B) and extensive microarray data relating to the genetic diversity of the Y. enterocolitica species. Our analysis reveals that the genome of Y. enterocolitica strain 8081 is a patchwork of horizontally acquired genetic loci, including a plasticity zone of 199 kb containing an extraordinarily high density of virulence genes. Microarray analysis has provided insights into species-specific Y. enterocolitica gene functions and the intraspecies differences between the high, low, and nonpathogenic Y. enterocolitica biotypes. Through comparative genome sequence analysis we provide new information on the evolution of the Yersinia. We identify numerous loci that represent ancestral clusters of genes potentially important in enteric survival and pathogenesis, which have been lost or are in the process of being lost, in the other sequenced Yersinia lineages. Our analysis also highlights large metabolic operons in Y. enterocolitica that are absent in the related enteropathogen, Yersinia pseudotuberculosis, indicating major differences in niche and nutrients used within the mammalian gut. These include clusters directing, the production of hydrogenases, tetrathionate respiration, cobalamin synthesis, and propanediol utilisation. Along with ancestral gene clusters, the genome of Y. enterocolitica has revealed species-specific and enteropathogen-specific loci. This has provided important insights into the pathology of this bacterium and, more broadly, into the evolution of the genus. Moreover, wider investigations looking at the patterns of gene loss and gain in the Yersinia have highlighted common themes in the genome evolution of other human enteropathogens

Understanding the key parameters for the rational design of layered oxide materials by composite sol-gel procedures

Previous works have well demonstrated that particle size of the filler used in layered oxide formulation is the first important parameter and must be decreased below 5 μm (Agrafiotis, 1999-2000 [10]). But once the particle size is set what are the next formulation parameters to highlight as critical? How do we improve cohesion and adhesion of the coatings? To highlight the key parameters driving the quality of coating, a model layered oxide material was prepared inside a pan granulator. The model composite sol gel formulation is based on boehmite nanoparticles (binder) and amonomodal two micrometer grain size gamma alumina (filler) which is applied onto alpha alumina beads substrate. The influences of the wetting method and relative amount of filler and binderwere investigated. Extensive characterization and imaging of the layered materials (SEM, Cryo-SEM, EPMA, Washburn test, mechanical tests, Hg-porosimetry) were used in order to follow the microstructure evolution of coating during and at the end of drying. Several crack propagation schemes were observed and explained qualitatively. Overall quality of coating is mainly related to the sol-gel transition of the binder. It defines if prior to shaping, the binder primer will be able to improve the coating adhesion and it defines also the nature and extent of damages that the coating undergoes during drying. The mechanical properties of layered oxide materials obtained using composite sol-gel formulation are definitely correlated with the binder gel shrinkage during drying

Structural basis for CRISPR RNA-guided DNA recognition by Cascade

The CRISPR (clustered regularly interspaced short palindromic repeats) immune system in prokaryotes uses small guide RNAs to neutralize invading viruses and plasmids. In Escherichia coli, immunity depends on a ribonucleoprotein complex called Cascade. Here we present the composition and low-resolution structure of Cascade and show how it recognizes double-stranded DNA (dsDNA) targets in a sequence-specific manner. Cascade is a 405-kDa complex comprising five functionally essential CRISPR-associated (Cas) proteins (CasA1B2C6D1E1) and a 61-nucleotide CRISPR RNA (crRNA) with 5′-hydroxyl and 2′,3′-cyclic phosphate termini. The crRNA guides Cascade to dsDNA target sequences by forming base pairs with the complementary DNA strand while displacing the noncomplementary strand to form an R-loop. Cascade recognizes target DNA without consuming ATP, which suggests that continuous invader DNA surveillance takes place without energy investment. The structure of Cascade shows an unusual seahorse shape that undergoes conformational changes when it binds target DNA.

The role of statistical learning in the acquisition of motion event construal in a second language

Learning to talk about motion in a second language is very difficult because it involves restructuring deeply entrenched patterns from the first language (Slobin 1996). In this paper we argue that statistical learning (Saffran et al. 1997) can explain why L2 learners are only partially successful in restructuring their second language grammars. We explore to what extent L2 learners make use of two mechanisms of statistical learning, entrenchment and pre-emption (Boyd and Goldberg 2011) to acquire target-like expressions of motion and retreat from overgeneralisation in this domain. Paying attention to the frequency of existing patterns in the input can help learners to adjust the frequency with which they use path and manner verbs in French but is insufficient to acquire the boundary crossing constraint (Slobin and Hoiting 1994) and learn what not to say. We also look at the role of language proficiency and exposure to French in explaining the findings

CRISPR Recognition Tool (CRT): a tool for automatic detection of clustered regularly interspaced palindromic repeats

<p>Abstract</p> <p>Background</p> <p>Clustered Regularly Interspaced Palindromic Repeats (CRISPRs) are a novel type of direct repeat found in a wide range of bacteria and archaea. CRISPRs are beginning to attract attention because of their proposed mechanism; that is, defending their hosts against invading extrachromosomal elements such as viruses. Existing repeat detection tools do a poor job of identifying CRISPRs due to the presence of unique spacer sequences separating the repeats. In this study, a new tool, CRT, is introduced that rapidly and accurately identifies CRISPRs in large DNA strings, such as genomes and metagenomes.</p> <p>Results</p> <p>CRT was compared to CRISPR detection tools, Patscan and Pilercr. In terms of correctness, CRT was shown to be very reliable, demonstrating significant improvements over Patscan for measures precision, recall and quality. When compared to Pilercr, CRT showed improved performance for recall and quality. In terms of speed, CRT proved to be a huge improvement over Patscan. Both CRT and Pilercr were comparable in speed, however CRT was faster for genomes containing large numbers of repeats.</p> <p>Conclusion</p> <p>In this paper a new tool was introduced for the automatic detection of CRISPR elements. This tool, CRT, showed some important improvements over current techniques for CRISPR identification. CRT's approach to detecting repetitive sequences is straightforward. It uses a simple sequential scan of a DNA sequence and detects repeats directly without any major conversion or preprocessing of the input. This leads to a program that is easy to describe and understand; yet it is very accurate, fast and memory efficient, being O(<it>n</it>) in space and O(<it>nm</it>/<it>l</it>) in time.</p

Vasodilator activity of extracts of field Alpinia purpurata (Vieill) K: Schum and A. zerumbet (Pers.) Burtt et Smith cultured in vitro

Nowadays, the high blood pressure is one of the main causes of death and cardiovascular diseases. Vasodilator drugs are frequently used to treat arterial hypertension. Experiments were undertaken to determine whether hydroalcoholic extracts obtained from leaves of field-grown Alpinia purpurata and A. zerumbet cultured in vitro under different plant growth regulators induce a vasodilator effect on Wistar rat mesenteric vascular bed pre-contracted with norepinephrine. Plant extracts were able to induce a long-lasting endothelium-dependent vasodilation. Efficiency on activity of A. purpurata reached 87% at concentration of 60 &#956;g. The extract of A. zerumbet maintained in medium containing IAA, induced the relaxation (17.4%) at 90 &#956;g, as compared to the control (MS0) that showed a better vasodilator effect (60%). These results are in agreement with the quantification of phenolic compounds in the extracts, which were 50% lower for those plants cultured in IAA. A. purpurata was assayed for the first time in relation to its vasodilator activity. This paper showed a strong probability of correlation between the pharmacological activities of A. purpurata with their content in phenolic compounds.Atualmente, a hipertensão arterial é uma das maiores causas de morte e de doenças cardiovasculares. Os vasodilatadores são freqüentemente utilizados no tratamento da hipertensão. Extratos hidroalcoólicos de Alpinia purpurata de campo e de A. zerumbet cultivada in vitro sob diferentes reguladores de crescimento vegetal foram ensaiados no leito mesentérico de ratos Wistar. Os extratos de A. purpurata e A. zerumbet produziram efeito vasodilatador com padrão de resposta dose-dependente de duração prolongada. Extratos da espécie A. purpurata tiveram efeito vasodilatador de 87% na dose de 60 &#956;g. O extrato obtido de folhas de A. zerumbet oriundas das culturas mantidas em meio contendo AIA (ácido indol acético) inibiu o relaxamento (17,4%) na dose de 90 &#956;g em relação ao controle (MS0), com o qual foi verificado melhor efeito vasodilatador (60%). Estes resultados estão de acordo com a concentração de fenóis totais que foi 50% menor para os extratos de plantas cultivadas in vitro em AIA. A espécie A. purpurata foi pela primeira vez ensaiada quanto à atividade vasodilatadora. Os resultados obtidos indicaram a presença de substâncias fenólicas provavelmente correlacionadas à ação terapêutica de A. purpurata

Multiple-Locus Variable-Number Tandem-Repeat Analysis of Pathogenic Yersinia enterocolitica in China

The predominant bioserotypes of pathogenic Yersinia enterocolitica in China are 2/O: 9 and 3/O: 3; no pathogenic O: 8 strains have been found to date. Multiple-Locus Variable-Number Tandem-Repeat Analysis (MLVA) based on seven loci was able to distinguish 104 genotypes among 218 pathogenic Y. enterocolitica isolates in China and from abroad, showing a high resolution. The major pathogenic serogroups in China, O: 3 and O: 9, were divided into two clusters based on MLVA genotyping. The different distribution of Y. enterocolitica MLVA genotypes maybe due to the recent dissemination of specific clones of 2/O: 9 and 3/O: 3 strains in China. MLVA was a helpful tool for bacterial pathogen surveillance and investigation of pathogenic Y. enterocolitica outbreaks