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1.
Microb Ecol ; 87(1): 78, 2024 May 29.
Article de Anglais | MEDLINE | ID: mdl-38806848

RÉSUMÉ

Fungi contribute to different important ecological processes, including decomposition of organic matter and nutrient cycling, but in the marine environment the main factors influencing their diversity and dynamics at the spatial and temporal levels are still largely unclear. In this study, we performed DNA metabarcoding on seawater sampled monthly over a year and a half in the Gulf of Trieste (northern Adriatic Sea), targeting the internal transcribed spacer (ITS) and the 18S rRNA gene regions. The fungal communities were diverse, very dynamic, and belonged predominantly to marine taxa. Samples could be clustered in two groups, mainly based on the high (> 30%) or low relative proportion of the ascomycetes Parengyodontium album, which emerged as a key taxon in this area. Dissolved and particulate organic C:N ratio played important roles in shaping the mycoplankton assemblages, suggesting that differently bioavailable organic matter pools may be utilized by different consortia. The proportion of fungal over total reads was 31% for ITS and 0.7% for 18S. ITS had the highest taxonomic resolution but low power to detect early divergent fungal lineages. Our results on composition, distribution, and environmental drivers extended our knowledge of the structure and function of the mycobiome of coastal waters.


Sujet(s)
Biodiversité , Champignons , ARN ribosomique 18S , Eau de mer , Eau de mer/microbiologie , Champignons/génétique , Champignons/classification , Champignons/isolement et purification , ARN ribosomique 18S/génétique , ARN ribosomique 18S/analyse , Mycobiome , ADN fongique/génétique , Codage à barres de l'ADN pour la taxonomie , Phylogenèse , Espaceur de l'ADN ribosomique/génétique , Espaceur de l'ADN ribosomique/analyse , Ascomycota/génétique , Ascomycota/classification , Ascomycota/isolement et purification
2.
Environ Microbiol ; 26(3): e16595, 2024 Mar.
Article de Anglais | MEDLINE | ID: mdl-38418391

RÉSUMÉ

In temperate coastal environments, wide fluctuations of biotic and abiotic factors drive microbiome dynamics. To link recurrent ecological patterns with planktonic microbial communities, we analysed a monthly-sampled 3-year time series of 16S rRNA amplicon sequencing data, alongside environmental variables, collected at two stations in the northern Adriatic Sea. Time series multivariate analyses allowed us to identify three stable, mature communities (climaxes), whose recurrence was mainly driven by changes in photoperiod and temperature. Mixotrophs (e.g., Ca. Nitrosopumilus, SUP05 clade, and Marine Group II) thrived under oligotrophic, low-light conditions, whereas copiotrophs (e.g., NS4 and NS5 clades) bloomed at higher temperatures and substrate availability. The early spring climax was characterised by a more diverse set of amplicon sequence variants, including copiotrophs associated with phytoplankton-derived organic matter degradation, and photo-auto/heterotrophic organisms (e.g., Synechococcus sp., Roseobacter clade), whose rhythmicity was linked to photoperiod lengthening. Through the identification of recurrent climax assemblages, we begin to delineate a typology of ecosystem based on microbiome composition and functionality, allowing for the intercomparison of microbial assemblages among different biomes, a still underachieved goal in the omics era.


Sujet(s)
Écosystème , Eau de mer , Eau de mer/composition chimique , ARN ribosomique 16S/génétique , Plancton/génétique , Phytoplancton/génétique , Archéobactéries/génétique
3.
Environ Sci Pollut Res Int ; 29(44): 67466-67482, 2022 Sep.
Article de Anglais | MEDLINE | ID: mdl-36056283

RÉSUMÉ

The Vibrionaceae family groups genetically and metabolically diverse bacteria thriving in all marine environments. Despite often representing a minor fraction of bacterial assemblages, members of this family can exploit a wide variety of nutritional sources, which makes them important players in biogeochemical dynamics. Furthermore, several Vibrionaceae species are well-known pathogens, posing a threat to human and animal health. Here, we applied the phylogenetic placement coupled with a consensus-based approach using 16S rRNA gene amplicon sequencing, aiming to reach a reliable and fine-level Vibrionaceae characterization and identify the dynamics of blooming, ecologically important, and potentially pathogenic species in different sites of the northern Adriatic Sea. Water samples were collected monthly at a Long-Term Ecological Research network site from 2018 to 2021, and in spring and summer of 2019 and 2020 at two sites affected by depurated sewage discharge. The 41 identified Vibrionaceae species represented generally below 1% of the sampled communities; blooms (up to ~ 11%) mainly formed by Vibrio chagasii and Vibrio owensii occurred in summer, linked to increasing temperature and particulate matter concentration. Pathogenic species such as Vibrio anguilllarum, Vibrio tapetis, and Photobacterium damselae were found in low abundance. Depuration plant samples were characterized by a lower abundance and diversity of Vibrionaceae species compared to seawater, highlighting that Vibrionaceae dynamics at sea are unlikely to be related to wastewater inputs. Our work represents a further step to improve the molecular approach based on short reads, toward a shared, updated, and curated phylogeny of the Vibrionaceae family.


Sujet(s)
Vibrionaceae , Animaux , Écosystème , Surveillance de l'environnement , Gènes d'ARN ribosomique , Humains , Matière particulaire , Phylogenèse , ARN ribosomique 16S/génétique , Eau de mer/microbiologie , Eaux d'égout , Vibrionaceae/génétique , Eaux usées , Eau
4.
Environ Microbiol Rep ; 14(4): 549-558, 2022 08.
Article de Anglais | MEDLINE | ID: mdl-35362215

RÉSUMÉ

Microbe-mediated enzymatic hydrolysis of organic matter entails the production of hydrolysate, the recovery of which may be more or less efficient. The selfish uptake mechanism, recently discovered, allows microbes to hydrolyze polysaccharides and take up large oligomers, which are then degraded in the periplasmic space. By minimizing the hydrolysate loss, selfish behaviour may be profitable for free-living cells dwelling in a patchy substrate landscape. However, selfish uptake seems to be tailored to algal-derived polysaccharides, abundant in organic particles, suggesting that particle-attached microbes may use this strategy. We tracked selfish polysaccharides uptake in surface microbial communities of the northeastern Mediterranean Sea, linking the occurrence of this processing mode with microbial lifestyle. Additionally, we set up fluorescently labelled polysaccharides incubations supplying phytodetritus to investigate a 'pioneer' scenario for particle-attached microbes. Under both conditions, selfish behaviour was almost exclusively carried out by particle-attached microbes, suggesting that this mechanism may represent an advantage in the race for particle exploitation. Our findings shed light on the selfish potential of particle-attached microbes, suggesting multifaceted foraging strategies exerted by particle colonizers.


Sujet(s)
Microbiote , Eau de mer , Bactéries/métabolisme , Mer Méditerranée , Polyosides/métabolisme , Eau de mer/microbiologie
5.
Mar Environ Res ; 164: 105245, 2021 Feb.
Article de Anglais | MEDLINE | ID: mdl-33429217

RÉSUMÉ

Marine heterotrophic prokaryotes degrade, transform, and utilize half of the organic matter (OM) produced by photosynthesis, either in dissolved or particulate form. Microbial metabolic rates are affected by a plethora of different factors, spanning from environmental variables to OM composition. To tease apart the environmental drivers underlying the observed organic matter utilization rates, we analysed a 21 year-long time series from the Gulf of Trieste (NE Adriatic Sea). Heterotrophic carbon production (HCP) time series analysis highlighted a long-term structure made up by three periods of coherent observations (1999-2007; 2008-2011; 2012-2019), shared also by OM concentration time series. Temporal patterns of HCP drivers, extracted with a random forest approach, demonstrated that a period of high salinity anomalies (2002-2008) was the main driver of this structure. The reduced river runoff and the consequent depletion of river-borne inorganic nutrients induced a long-term Chl a decline (2006-2009), followed by a steady increase until 2014. HCP driving features over the three periods substantially changed in their seasonal patterns, suggesting that the years following the draught period represented a transition between two long-term regimes. Overall, temperature and particulate organic carbon concentration were the main factors driving HCP rates. The emergence of these variables highlighted the strong control exerted by the temperature-substrate co-limitation on microbial growth. Further exploration revealed that HCP rates did not follow the Arrhenius' linear response to temperature between 2008 and 2011, demonstrating that microbial growth was substrate-limited following the draught event. By teasing apart the environmental drivers of microbial growth on a long-term perspective, we demonstrated that a substantial change happened in the biogeochemistry of one of the most productive areas of the Mediterranean Sea. As planktonic microbes are the foundation of marine ecosystems, understanding their past dynamics may help to explain present and future changes.


Sujet(s)
Écosystème , Rivières , Carbone/analyse , Mer Méditerranée , Plancton
6.
Front Microbiol ; 11: 1242, 2020.
Article de Anglais | MEDLINE | ID: mdl-32582131

RÉSUMÉ

Particulate organic matter (POM) export represents the underlying principle of the biological carbon pump, driving the carbon flux from the sunlit to the dark ocean. The efficiency of this process is tightly linked to the prokaryotic community, as >70% of POM respiration is carried out by particle-associated prokaryotes. In the Ross Sea, one of the most productive areas of the Southern Ocean, up to 50% of the surface primary production is exported to the mesopelagic ocean as POM. Recent evidence suggests that a significant fraction of the POM in this area is composed of intact phytoplankton cells. During austral summer 2017, we set up bottle enrichment experiments in which we amended free-living surface and deep prokaryotic communities with organic matter pools generated from native microplankton, mimicking the particle export that may derive from mild (1 µg of Chlorophyll a L-1) and intense (10 µg of Chlorophyll a L-1) phytoplankton bloom. Over a course of 4 days, we followed free-living and particle-attached prokaryotes' abundance, the degradation rates of polysaccharides, proteins and lipids, heterotrophic production as well as inorganic carbon utilization and prokaryotic community structure dynamics. Our results showed that several rare or undetected taxa in the initial community became dominant during the time course of the incubations and that different phytodetritus-derived organic matter sources induced specific changes in microbial communities, selecting for peculiar degradation and utilization processes spectra. Moreover, the features of the supplied detritus (in terms of microplankton taxa composition) determined different colonization dynamics and organic matter processing modes. Our study provides insights into the mechanisms underlying the prokaryotic utilization of phytodetritus, a significant pool of organic matter in the dark ocean.

7.
J Clin Med ; 9(4)2020 Apr 13.
Article de Anglais | MEDLINE | ID: mdl-32294983

RÉSUMÉ

Sacubitril/valsartan therapy reduces sudden cardiac death (SCD) among patients with reduced ejection fraction (HFrEF) when compared to guidelines recommended doses of enalapril, however the mechanism is still not clear. There are few, contrasting results about the effect of sacubitril/valsartan on arrhythmias in the clinical context of dilated cardiomyopathy (DCM) and there are no clinical data about its effect on measured implantable cardioverter defibrillator (ICD) electrical parameters, such as atrial/ventricular electrograms sensing and pacing threshold. We conducted a 12 month follow-up observational study in 167 ischemic and nonischemic DCM patients (mean age 68.1 ± 11.6 years; 85% male), with dual-chamber ICD on sacubitril/valsartan treatment, to evaluate the incidence of device detected tachyarrhythmia events, both atrial and ventricular, and the change in measured ICD electrical parameters. We collected data on clinical, electrocardiographic and echocardiographic parameters to find a possible electro-mechanical correlation within results. Our results show that DCM patients with reduced ejection fraction and ICD on sacubitril/valsartan treatment experienced a reduction in both atrial and ventricular arrhythmias incidence and an improvement in ICD electrical atrial parameters. The findings might be explained by the electro-mechanical cardiac reverse remodeling induced by sacubitril/valsartan therapy.

8.
Riv Psichiatr ; 53(2): 65-79, 2018.
Article de Italien | MEDLINE | ID: mdl-29674774

RÉSUMÉ

In recent years, mature industrial countries are rapidly changing from production economies to service economies. In this new socio-economic context, particular attention has been paid to mental health problems in the workplace. The risk of burnout is significantly higher for certain occupations, in particular for health workers. Doctors and psychiatrists, in particular, quite frequently have to make quick decisions by dealing with a huge amount of requests, which often require considerable assumptions of responsibility. In Italy, the process of corporateization and regionalization of the National Health Service has oriented clinical practice, in psychiatry, towards the rationalization and optimization of available resources, to ensure appropriateness and fairness of performances. The challenge that will soon be faced in health policy, with the progressive aging of the population, will be the growing burden of chronicity, in a context of limited resources, which will necessarily require a managerial approach in structuring and delivering services. The management of change in psychiatric assistance, today in Italy, can not be separated from a deep motivating involvement ( engagement) of professionals. In other words, it is desirable, in the effort to contain expenditure and rationalize welfare processes, to shift from burnout to the engagement of psychiatrists, investing economic and human resources in mental health services. In this review, through a selective search of the relevant literature 2010-2017 conducted on PubMed (key words: stress, burnout, psychiatry, mental health), the information from original articles, reviews and book chapters was analyzed and summarized. about the presence of burnout syndrome among psychiatrists. This article examines the concept of burnout, its causes and the most appropriate preventive and therapeutic interventions applicable to psychiatrists.


Sujet(s)
Épuisement professionnel/épidémiologie , Psychiatrie , Épuisement professionnel/diagnostic , Épuisement professionnel/étiologie , Épuisement professionnel/prévention et contrôle , Usure de compassion/épidémiologie , Usure de compassion/psychologie , Prestations des soins de santé , Dépression/épidémiologie , Dépression/étiologie , Rationnement des services de santé , Humains , Italie , Modèles psychologiques , Programmes nationaux de santé , Dynamique des populations , Risque , Indice de gravité de la maladie , Changement social , Engagement dans le travail
9.
ScientificWorldJournal ; 2015: 265751, 2015.
Article de Anglais | MEDLINE | ID: mdl-25685836

RÉSUMÉ

The objectives of the present study were to characterize the MC1R gene, its transcripts and the single nucleotide polymorphisms (SNPs) associated with coat color in alpaca. Full length cDNA amplification revealed the presence of two transcripts, named as F1 and F2, differing only in the length of their 5'-terminal untranslated region (UTR) sequences and presenting a color specific expression. Whereas the F1 transcript was common to white and colored (black and brown) alpaca phenotypes, the shorter F2 transcript was specific to white alpaca. Further sequencing of the MC1R gene in white and colored alpaca identified a total of twelve SNPs; among those nine (four silent mutations (c.126C>A, c.354T>C, c.618G>A, and c.933G>A); five missense mutations (c.82A>G, c.92C>T, c.259A>G, c.376A>G, and c.901C>T)) were observed in coding region and three in the 3'UTR. A 4 bp deletion (c.224 227del) was also identified in the coding region. Molecular segregation analysis uncovered that the combinatory mutations in the MC1R locus could cause eumelanin and pheomelanin synthesis in alpaca. Overall, our data refine what is known about the MC1R gene and provides additional information on its role in alpaca pigmentation.


Sujet(s)
Camélidés du Nouveau Monde/génétique , Polymorphisme de nucléotide simple/génétique , Récepteur de la mélanocortine de type 1/génétique , Peau/composition chimique , Régions 3' non traduites/génétique , Régions 5' non traduites/génétique , Séquence d'acides aminés , Animaux , Séquence nucléotidique , Camélidés du Nouveau Monde/métabolisme , Clonage moléculaire , Expression des gènes , Couleur des cheveux/génétique , Données de séquences moléculaires , Mutation faux-sens/génétique , Techniques d'amplification d'acides nucléiques/médecine vétérinaire , Récepteur de la mélanocortine de type 1/analyse , Alignement de séquences/médecine vétérinaire , Mutation inapparente/génétique
10.
Gene ; 521(2): 303-10, 2013 Jun 01.
Article de Anglais | MEDLINE | ID: mdl-23558248

RÉSUMÉ

The agouti gene encodes the agouti signaling protein (ASIP) which regulates pheomelanin and eumelanin synthesis in mammals. To investigate the role of agouti in coat color variation of alpaca, we characterized the agouti gene and identified three mutations potentially involved with the determinism of eumelanic and pheomelanic phenotypes. The exon-4 hosts the mutations g.3836C>T, g.3896G>A and g.3866_3923del57. Further analysis of these mutations revealed two genotypes for black animals. The reverse transcription analysis of mRNA purified from skin biopsies of alpaca revealed the presence of three transcripts with different 5' untranslated regions (UTRs) and color specific expression. The white specific transcript, possibly originating from a duplication event (intra-chromosomal recombination) of the agouti gene is characterise by a 5'UTR containing 142bp of the NCOA6 gene sequence. Furthermore, the relative level expression analysis of mRNA demonstrates that the agouti gene has up-regulated expression in white skin, suggesting a pleiotropic effect of agouti in the white phenotype. Our findings refine the structure of the agouti locus and transcripts and provide additional information in order to understand the role of agouti in the pigmentation of alpaca.


Sujet(s)
Protéine de signalisation Agouti/génétique , Camélidés du Nouveau Monde/génétique , Locus génétiques , Mélanines/génétique , Mutation , Régions 5' non traduites/génétique , Séquence d'acides aminés , Animaux , Séquence nucléotidique , Couleur , Exons/effets des médicaments et des substances chimiques , Génotype , Données de séquences moléculaires , Phénotype , ARN messager/génétique , Alignement de séquences , Peau
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