3,808 research outputs found
Effect of Lactobacillus rhamnosus HN001 and Bifidobacterium longum BB536 on the healthy gut microbiota composition at phyla and species level: a preliminary study
AIM:
To evaluate the ability of Lactobacillus rhamnosus HN001 and Bifidobacterium longum BB536 to colonize the intestinal environment of healthy subjects and modify the gut microbiota composition.
METHODS:
Twenty healthy Italian volunteers, eight males and twelve females, participated in the study. Ten subjects took a sachet containing 4 Ă 109 colony-forming units (CFU) of Bifidobacterium longum BB536 and 109 CFU of Lactobacillus rhamnosus HN001, 30 min before breakfast (pre-prandial administration), while ten subjects took a sachet of probiotic product 30 min after breakfast (post-prandial administration). The ability of Lactobacillus rhamnosus HN001 and Bifidobacterium longum BB536 to colonize human gut microbiota was assessed by means of quantitative real-time PCR, while changes in gut microbiota composition were detected by using Ion Torrent Personal Genome Machine.
RESULTS:
Immediately after 1-mo of probiotic administration, B. longum BB536 and L. rhamnosus HN001 load was increased in the majority of subjects in both pre-prandial and post-prandial groups. This increase was found also 1 mo after the end of probiotic oral intake in both groups, if compared to samples collected before probiotic consumption. At phyla level a significant decrease in Firmicutes abundance was detected immediately after 1-mo of B. longum BB536 and L. rhamnosus HN001 oral intake. This reduction persisted up to 1 mo after the end of probiotic oral intake together with a significant decrease of Proteobacteria abundance if compared to samples collected before probiotic administration. Whereas, at species level, a higher abundance of Blautia producta, Blautia wexlerae and Haemophilus ducrey was observed, together with a reduction of Holdemania filiformis, Escherichia vulneris, Gemmiger formicilis and Streptococcus sinensis abundance. In addition, during follow-up period we observed a further reduction in Escherichia vulneris and Gemmiger formicilis, together with a decrease in Roseburia faecis and Ruminococcus gnavus abundance. Conversely, the abundance of Akkermansia muciniphila was increased if compared to samples collected at the beginning of the experimental time course.
CONCLUSION:
B. longum BB536 and L. rhamnosus HN001 showed the ability to modulate the gut microbiota composition, leading to a significant reduction of potentially harmful bacteria and an increase of beneficial ones. Further studies are needed to better understand the specific mechanisms involved in gut microbiota modulation
A discrete chemo-dynamical model of the dwarf spheroidal galaxy Sculptor: mass profile, velocity anisotropy and internal rotation
We present a new discrete chemo-dynamical axisymmetric modeling technique,
which we apply to the dwarf spheroidal galaxy Sculptor. The major improvement
over previous Jeans models is that realistic chemical distributions are
included directly in the dynamical modelling of the discrete data. This avoids
loss of information due to spatial binning and eliminates the need for hard
cuts to remove contaminants and to separate stars based on their chemical
properties. Using a combined likelihood in position, metallicity and
kinematics, we find that our models naturally separate Sculptor stars into a
metal-rich and a metal-poor population. Allowing for non-spherical symmetry,
our approach provides a central slope of the dark matter density of . The metal-rich population is nearly isotropic (with
) while the metal-poor population is tangentially
anisotropic (with ) around the half light radius
of kpc. A weak internal rotation of the metal-rich population is
revealed with . We run tests using mock data
to show that a discrete dataset with stars is required to
distinguish between a core () and cusp (), and to
constrain the possible internal rotation to better than confidence
with our model. We conclude that our discrete chemo-dynamical modelling
technique provides a flexible and powerful tool to robustly constrain the
internal dynamics of multiple populations, and the total mass distribution in a
stellar system.Comment: Accepted by MNRA
Identifying conformational changes with site-directed spin labeling reveals that the GTPase domain of HydF is a molecular switch
[FeFe]-hydrogenases catalyse the reduction of protons to hydrogen at a complex 2Fe[4Fe4S] center called H-cluster. The assembly of this active site is a multistep process involving three proteins, HydE, HydF and HydG. According to the current models, HydF has the key double role of scaffold, upon which the final H-cluster precursor is assembled, and carrier to transfer it to the target hydrogenase. The X-ray structure of HydF indicates that the protein is a homodimer with both monomers carrying two functional domains: a C-terminal FeS cluster-binding domain, where the precursor is assembled, and a N-terminal GTPase domain, whose exact contribution to cluster biogenesis and hydrogenase activation is still elusive. We previously obtained several hints suggesting that the binding of GTP to HydF could be involved in the interactions of this scaffold protein with the other maturases and with the hydrogenase itself. In this work, by means of site directed spin labeling coupled to EPR/PELDOR spectroscopy, we explored the conformational changes induced in a recombinant HydF protein by GTP binding, and provide the first clue that the HydF GTPase domain could be involved in the H-cluster assembly working as a molecular switch similarly to other known small GTPases
Stabilized mixed formulation for phase-field computation of deviatoric fracture in elastic and poroelastic materials
In the numerical approximation of phase-field models of fracture in porous media with the finite element method, the problem of numerical locking may occur. The causes can be traced both to the hydraulic and to the mechanical properties of the material. In this work we present a mixed finite element formulation for phase-field modeling of brittle fracture in elastic solids based on a volumetric-deviatoric energy split and its extension to water saturated porous media. For the latter, two alternative mixed formulations are proposed. To be able to use finite elements with linear interpolation for all the field variables, which violates the Ladyzenskaja-Babuska-Brezzi condition, a stabilization technique based on polynomial pressure projections, proposed and tested by previous authors in fluid mechanics and poromechanics, is introduced. We develop an extension of this stabilization to phase-field mixed models of brittle fracture in porous media. Several numerical examples are illustrated, to show the occurrence of different locking phenomena and to compare the solutions obtained with different unstable, stable and stabilized low order finite elements
Evaluation of the masonry and timber structures of San Francisco Church in Santiago de Cuba through nondestructive diagnostic methods
Recently, due to a renewed interest in the religious architectural heritage of the Caribbean island of Cuba, some important interventions for the restoration and reinforcement of the colonial churches of the island were carried out. The authors, collaborating with the Archdiocese of Santiago de Cuba in a project concerning the protection of Cuban churches, applied some nondestructive and noninvasive destructive tests for an in-depth study of the main characteristics of those structures. The diagnostic method, developed mainly for the historical buildings or monuments of Europe and North America, was used to study some peculiarities of the building construction traditions of this area. The proposed techniques revealed the existence of several original solutions, for example, defenses for seismic mitigation, developed to resist the earthquakes that frequently affect the area
Noncanonical Alternative Polyadenylation Contributes to Gene Regulation in Response to Hypoxia
Stresses from various environmental challenges continually confront plants, and their responses are important for growth and survival. One molecular response to such challenges involves the alternative polyadenylation of mRNA. In plants, it is unclear how stress affects the production and fate of alternative mRNA isoforms. Using a genome-scale approach, we show that in Arabidopsis thaliana, hypoxia leads to increases in the number of mRNA isoforms with polyadenylated 3âČ ends that map to 5âČ-untranslated regions (UTRs), introns, and protein-coding regions. RNAs with 3âČ ends within protein-coding regions and introns were less stable than mRNAs that end at 3âČ-UTR poly(A) sites. Additionally, these RNA isoforms were underrepresented in polysomes isolated from control and hypoxic plants. By contrast, mRNA isoforms with 3âČ ends that lie within annotated 5âČ-UTRs were overrepresented in polysomes and were as stable as canonical mRNA isoforms. These results indicate that the generation of noncanonical mRNA isoforms is an important feature of the abiotic stress response. The finding that several noncanonical mRNA isoforms are relatively unstable suggests that the production of non-stop and intronic mRNA isoforms may represent a form of negative regulation in plants, providing a conceptual link with mechanisms that generate these isoforms (such as alternative polyadenylation) and RNA surveillance
A Cross-Sectional Survey on Burnout Prevalence and Profile in the Sicilian Population of Ambulance Driver-Rescuers
Introduction: Burnout is present at a high rate in emergency medicine. The ambulance
driver-rescuers, who furnish first aid to the victims, are the non-medical part of the
Italian 118-service staff. There is a lack of research on burnout risk in Italian Emergency
Medical Services and, particularly, for this category of workers. The two Italian studies,
including a little group of ambulance driver-rescuers, reported inconsistent findings.
Hypothesis: This survey investigated for the first time the prevalence and exact profile of
burnout in a large sample of Italian driver-rescuers. As a secondary aim, the study described
how the items of the Italian version of the Maslach Burnout Inventory-Human Services
Survey (MBI-HSS) cluster in components in this sample.
Methods: This cross-sectional census survey was conducted from June 2015 through May
2016 and involved all the driver-rescuers operating in Sicily, the biggest and most southern
region of Italy. The subjects received a classification according to different profiles of burnout by using the Italian version of the MBI-HSS (burnout, engagement, disengagement,
over-extension, and work-inefficacy). In order to explore the existence of independent
factors, a Principal Component Analysis (PCA) was conducted on the survey to obtain
eigenvalues >one for each component in the data.
Results: The final sample comprised 2,361 responders (96.6% of the initial sample). Of them,
29.8% were in burnout (95% confidence interval [CI], 27.8% to 31.8%) and 1.7% presented a
severe form (95% CI, 1.1% to 2.3%); 30.0% were engaged in their work (95% CI, 21.0% to
34.8%), 24.7% of responders were disengaged (95% CI, 22.9% to 26.5%), 1.2% presented an
over-extension profile (95% CI, 0.8% to 1.7%), and 12.6% felt work-inefficacy (95% CI,
11.3% to 14.1%). The factors loaded into a five-factor solution at PCA, explaining 48.1%
of the variance and partially replicating the three-factor structure. The Emotional
Exhaustion (EE) component was confirmed. New dimensions from Personal
Accomplishment (PA) and Depersonalization (DP) sub-scales described empathy and disengagement with patients, respectively, and were responsible for the increased risk of burnout.
Conclusions: These results endorse the importance of screening and psychological interventions for this population of emergency workers, where burnout could manifest itself more
insidiously. It is also possible to speculate that sub-optimal empathy skills could be related to
the disengagement and work-inefficacy feelings registered
PRIMUS/Informed Cities: Making research work for local sustainability
The final report of a three year European Commission FP7 project
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