Seasonal to hour variation scales in abundance and production of total and particle-attached bacteria in the open NW Mediterranean Sea (0–1000 m)

We present the vertical and temporal dynamics of total <i>vs.</i> particle-attached bacterial abundance and activity over a 5 week period under summer to autumn transition in NW Mediterranean Sea. At a weekly time scale, total bacterial biomass and production in the euphotic layers was significantly correlated with phytoplanktonic biomass. At an hourly time scale, total bacterial biomass responded very rapidly to chlorophyll <i>a</i> fluctuations, suggesting a tight coupling between phytoplankton and bacteria for resource partitioning during the summer-autumn transition. In contrast, no influence of diel changes on bacterial parameters was detected. Episodic events such as coastal water intrusions had a significant positive effect on total bacterial abundance and production, whereas we could not detect any influence of short wind events whatever the magnitude. Finally, we show that particle-attached bacteria can represent a large proportion (up to 49%) of the total bacterial activity in the euphotic layer but display rapid and sporadic changes at hourly time scales. In the mesopelagic layers, bacterial abundance and production linearly decreased with depth, except some production peaks at 400–750 m. This study underlines the value of large datasets covering different temporal scales to clarify the biogeochemical role of bacteria in the cycling of organic matter in open seawater

Role of environmental factors for the vertical distribution (0–1000 m) of marine bacterial communities in the NW Mediterranean Sea

Bacterioplankton plays a central role in energy and matter fluxes in the sea, yet the factors that constrain its variation in marine systems are still poorly understood. Here we use the explanatory power of direct multivariate gradient analysis to evaluate the driving forces exerted by environmental parameters on bacterial community distribution in the water column. We gathered and analysed data from a one month sampling period from the surface to 1000 m depth at the JGOFS-DYFAMED station (NW Mediterranean Sea). This station is characterized by very poor horizontal advection currents which makes it an ideal model to test hypotheses on the causes of vertical stratification of bacterial communities. Capillary electrophoresis single strand conformation polymorphism (CE-SSCP) fingerprinting profiles analyzed using multivariate statistical methods demonstrated a vertical zonation of bacterial assemblages in three layers, above, in or just below the chlorophyll maximum and deeper, that remained stable during the entire sampling period. Through the use of direct gradient multivariate ordination analyses we demonstrate that a complex array of biogeochemical parameters is the driving force behind bacterial community structure shifts in the water column. Physico-chemical parameters such as phosphate, nitrate, salinity and to a lesser extent temperature, oxygen, dissolved organic carbon and photosynthetically active radiation acted in synergy to explain bacterial assemblages changes with depth. Analysis of lipid biomarkers of organic matter sources and fates suggested that bacterial community structure in the surface layers was in part explained by lipids of chloroplast origin. Further detailed analysis of pigment-based phytoplankton diversity gave evidence of a compartmentalized influence of several phytoplankton groups on bacterial community structure in the first 150 m depth

Structural and biochemical characterization of the novel CTXM-151 extended-spectrum β-lactamase and its inhibition by avibactam

The diazabicyclooctane (DBO) inhibitor avibactam (AVI) reversibly inactivates most serine β-lactamases, including the CTX-M β-lactamases. Currently, more than 230 unique CTX-M members distributed in five clusters with less than 5% amino acid sequence divergence within each group have been described. Recently, a variant named CTX-M-151 was isolated from a Salmonella enterica subsp. enterica serovar Choleraesuis strain in Japan. This variant possesses a low degree of amino acid identity with the other CTX-Ms (63.2% to 69.7% with respect to the mature proteins), and thus it may represent a new subgroup within the family. CTX-M-151 hydrolyzes ceftriaxone better than ceftazidime (kcat/Km values 6,000-fold higher), as observed with CTX-Ms. CTX-M-151 is well inhibited by mechanism-based inhibitors like clavulanic acid (inactivation rate [kinact]/inhibition constant [Ki] = 0.15μM-1 · s-1). For AVI, the apparent inhibition constant (Ki app), 0.4mM, was comparable to that of KPC-2; the acylation rate (k2/K) (37,000 M-1 · s-1) was lower than that for CTX-M-15, while the deacylation rate (koff) (0.0015 s21) was 2- to 14-fold higher than those of other class A β-lactamases. The structure of the CTX-M-151/AVI complex (1.32 Å) reveals that AVI adopts a chair conformation with hydrogen bonds between the AVI carbamate and Ser70 and Ser237 at the oxyanion hole. Upon acylation, the side chain of Lys73 points toward Ser130, which is associated with the protonation of Glu166, supporting the role of Lys73 in the proton relay pathway and Glu166 as the general base in deacylation. To our knowledge, this is the first chromosomally encoded CTX-M in Salmonella Choleraesuis that shows similar hydrolytic preference toward cefotaxime (CTX) and ceftriaxone (CRO) to that toward ceftazidime (CAZ).Fil: Ghiglione, Barbara. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Instituto de Investigaciones En Bacteriologia y Virologia Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Rodríguez, María Margarita. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Instituto de Investigaciones En Bacteriologia y Virologia Molecular; ArgentinaFil: Brunetti, Florencia Lourdes. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Instituto de Investigaciones En Bacteriologia y Virologia Molecular; ArgentinaFil: Papp Wallace, Krisztina M.. Case Western Reserve University; Estados UnidosFil: Yoshizumi, Ayumi. Toho University; JapónFil: Ishii, Yoshikazu. Toho University; JapónFil: Bonomo, Robert A.. Case Western Reserve University; Estados UnidosFil: Gutkind, Gabriel Osvaldo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Instituto de Investigaciones En Bacteriologia y Virologia Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Klinke, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Power, Pablo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Instituto de Investigaciones En Bacteriologia y Virologia Molecular; Argentin

Petrology and tectonic evolution of late Paleozoic mafic-ultramafic sequences and the Leones Pluton of the Eastern Andean Metamorphic Complex (46-47°S), southern Chile

The metamorphosed mafic-ultramafic sequences of the Eastern Andean Metamorphic Complex outcropping in the Patagonian Andes are critical to disclose the late Paleozoic tectonic evolution of the southwestern margin of Gondwana. In the study area, mafic-ultramafic bodies are thrusted onto polydeformed metasedimentary rocks and intruded by the mid-Carboniferous composite Leones Pluton. The metabasalts (mostly tremolite-chlorite schists and amphibolites) show N-MORB and BABB chemical affinities pointing that formed part of an oceanic crustal section with components of the marginal basin, emplaced after the main pulse of Devonian arc magmatism, possibly in a retreating convergent margin. Interleaved serpentinites consist of serpentine polymorphs (antigorite, lizardite, and late chrysotile) and magnetite, with variably distributed minor amounts of chlorite, tremolite, and traces of ilmenite. Serpentinites have high Cr, Ni, Ti, and Yb contents, and show slightly enriched LREE and flat HREE patterns with a noticeable Eu positive anomaly. Mineralogical and geochemical features indicate that olivine-rich clinopyroxene-spinel-bearing peridotites were metamorphosed in a newly formed east-dipping subduction zone. The closure of the marginal basin continued with the tectonic underthrusting and tectonic juxtaposition of mafic-ultramafic rocks within an accretionary wedge. The tectonic cycle of the oceanic basin finished with the intrusion of mid-Carboniferous subduction-related plutons and pluton-driven thermal metamorphism.Fil: Rojo, D.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad Arturo Prat; ChileFil: Calderón, M.. Universidad Andrés Bello; ChileFil: Hervé, F.. Universidad Andrés Bello; ChileFil: Díaz, J.. Universidad Andrés Bello; ChileFil: Quezada, P.. Universidade Federal do Paraná; Brasil. Universidad de Aysén; ChileFil: Suárez, Rodrigo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Ghiglione, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Fuentes, F.. Universidad Mayor; ChileFil: Theye, T.. Universität Stuttgart; AlemaniaFil: Cataldo, J.. Universidad Andrés Bello; ChileFil: Sándoval, J.. Universidad Andrés Bello; ChileFil: Viefhaus, T.. Universität Stuttgart; Alemani

Early skewed differentiation and PD-1 expression in CD4+ cells relate to immune dysfunction and viral persistence in individuals living with HIV 1 year post-cART initiation

Achieving HIV functional cure is a priority. Strategies such as adoptive cell transfer have been assayed, without success yet mainly due to immune dysfunctions observed among individuals. Samples from 25 HIV+ subjects were collected at diagnosis (baseline sample, BSL) and one year post-cART initiation (post- cART ). At BSL, bulk and HIV-specific CD4 phenotype (CD45RO , CCR 7, CD95 and PD1 expression) was assessed by flow cytometry after a short stimulation with HIV peptides. Also, proportion of CD4+/HLA-DR+/ CD38+ cells was measured. At post-cART , HIV-specific CD8TC s were obtained after 2-week expansion with peptides. Phenotype and antiviral activity (VIA and VITA L assays) were evaluated post-expansion. Plasma CXCL10 (IP-10) was assessed by ELISA. Cell-associated HIV DNA (total and integrated) and unspliced (US) and multiply-spliced (MS) RNA were quantified by real-time PCR. Non-parametric statistics were applied. Early CD4TC exhaustion, elevated activation and inadequate differentiation seem to be associated with viral persistence, inflammation, as well as with the phenotype and antiviral capacity of HIV-specific CD8TC s that persist one year after cART is initiated. These parameters could serve as predictors of CD8TC function on treated subjects.Fil: Salido, Jimena Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Czernikier, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Trifone, César Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Figueroa, M. I.. Fundación Huésped; ArgentinaFil: Salomon, Horacio Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Cahn, P.. Fundación Huésped; ArgentinaFil: Sued, O.. Fundación Huésped; ArgentinaFil: Laufer, Natalia Lorna. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Juan A. Fernández"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Ghiglione, Yanina Alexandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: Turk, Gabriela Julia Ana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentin

Sedimentological imprint on subseafloor microbial communities in Western Mediterranean Sea Quaternary sediments

An interdisciplinary study was conducted to evaluate the relationship between geological and paleoenvironmental parameters and the bacterial and archaeal community structure of two contrasting subseafloor sites in the Western Mediterranean Sea (Ligurian Sea and Gulf of Lion). Both depositional environments in this area are well-documented from paleoclimatic and paleooceanographic point of views. Available data sets allowed us to calibrate the investigated cores with reference and dated cores previously collected in the same area, and notably correlated to Quaternary climate variations. DNA-based fingerprints showed that the archaeal diversity was composed by one group, Miscellaneous Crenarchaeotic Group (MCG), within the Gulf of Lion sediments and of nine different lineages (dominated by MCG, South African Gold Mine Euryarchaeotal Group (SAGMEG) and <i>Halobacteria</i>) within the Ligurian Sea sediments. Bacterial molecular diversity at both sites revealed mostly the presence of the classes <i>Alphaproteobacteria</i>, <i>Betaproteobacteria</i> and <i>Gammaproteobacteria</i> within <i>Proteobacteria</i> phylum, and also members of <i>Bacteroidetes</i> phylum. The second most abundant lineages were <i>Actinobacteria</i> and <i>Firmicutes</i> at the Gulf of Lion site and <i>Chloroflexi</i> at the Ligurian Sea site. Various substrates and cultivation conditions allowed us to isolate 75 strains belonging to four lineages: <i>Alpha-</i>, <i>Gammaproteobacteria</i>, <i>Firmicutes</i> and <i>Actinobacteria</i>. In molecular surveys, the <i>Betaproteobacteria</i> group was consistently detected in the Ligurian Sea sediments, characterized by a heterolithic facies with numerous turbidites from a deep-sea <i>levee</i>. Analysis of relative betaproteobacterial abundances and turbidite frequency suggested that the microbial diversity was a result of main climatic changes occurring during the last 20 ka. Statistical direct multivariate canonical correspondence analyses (CCA) showed that the availability of electron acceptors and the quality of electron donors (indicated by age) strongly influenced the community structure. In contrast, within the Gulf of Lion core, characterized by a homogeneous lithological structure of upper-slope environment, most detected groups were <i>Bacteroidetes</i> and, to a lesser extent, <i>Betaproteobacteria</i>. At both site, the detection of <i>Betaproteobacteria</i> coincided with increased terrestrial inputs, as confirmed by the geochemical measurements (Si, Sr, Ti and Ca). In the Gulf of Lion, geochemical parameters were also found to drive microbial community composition. Taken together, our data suggest that the palaeoenvironmental history of erosion and deposition recorded in the Western Mediterranean Sea sediments has left its imprint on the sedimentological context for microbial habitability, and then indirectly on structure and composition of the microbial communities during the late Quaternary

Diversidad y grupos funcionales de insectos en cultivos de arroz y sus bordes bajo manejo convencional y agroecológico en Santa Fe, Argentina

El arroz es el cereal de mayor producción considerado el alimento base para el 50% de la población mundial. Los objetivos del trabajo fueron i) conocer la diversidad de insectos que presentan los cultivos de arroz y sus bordes ii) caracterizar grupos funcionales según el rol ecosistémico que cumplen los insectos en cultivos de arroz y sus bordes con diferente tipo de manejo iii) analizar las interacciones de los grupos funcionales con la vegetación de los bordes. Los muestreos se realizaron durante un ciclo de producción primavera-verano (2017-2018), en cultivos de arroz con prácticas de manejo convencional (MC) y agroecológico (MA). Se capturaron 1005 ejemplares pertenecientes a 244 especies y morfoespecies. Los bordes presentaron mayor riqueza, abundancia y diversidad de Shannon en relación al cultivo, siendo el MA destacado por la presencia de los cinco grupos funcionales. En ambos manejos, se presenció Sepedonea sp., Protodictya sp. y Eryopis connexa (L.) como controladores de gasterópodos e insectos plagas. Se registraron 397 interacciones insecto-planta en MA y 175 en MC. Se destaca la importancia de los bordes y las prácticas MA en el cultivo de arroz para favorecer la conservación de entomofauna y potenciar los servicios ecosistémicos que éstos brindan a los sistemas productivos.Ecosystem services provided by insects, such as pollination and pest control, are essential for food production and agricultural health. The aims of this work were to 1) compare insect diversity in rice crops and their containment edges in two farms under different management systems (conventional and agroecological), 2) characterize functional groups of insects in rice crops and their containment edges, under different management systems, and 3) analyze the interactions of functional groups of insects with vegetation in the containment edges. Sampling was conducted during a rice production cycle in the spring-summer 2017-2018 in farms under conventional management practices (EMC) and agroecological management (EMA) in an area of intensive rice production (San Javier Department, Santa Fe, Argentina). A total of 1008 insects belonging to 236 species and morphospecies were captured using entomological nets. Containment edges exhibited higher richness, abundance and diversity than crops, with the EMA standing out for the presence of all five functional groups. On both farms, Sepedonea sp., Protodictya sp. and Eryopis connexa (L.), known control agents of gastropods and insect pests, were recorded. A total of 397 insect-plant interactions were registered in agroecological containment edges, and only 175 in conventional ones. The results obtained in this work make a novel contribution to the knowledge of insects present in containment edges and in rice crops. This work provides knowledge on the diversity, composition and distribution of the insect community, as well as data on the floral offer of the vegetation growing in containment edges and its relationship with the entomofauna.EEA RafaelaFil: Ghiglione, Carla. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Cátedra de Entomología; ArgentinaFil: Zumoffen, Leticia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Agencia de Extensión Rural Monte Vera; ArgentinaFil: Zumoffen, Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Dalmazzo, Maria de los Milagros. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Cátedra de Entomología; ArgentinaFil: Dalmazzo, Maria de los Milagros. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Strasser, Ruth. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Cátedra de Entomología; ArgentinaFil: Attademo, Andres M. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Laboratorio de Ecotoxicología; ArgentinaFil: Attademo, Andres M. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Lateral Gene Expression in Drosophila Early Embryos Is Supported by Grainyhead-Mediated Activation and Tiers of Dorsally-Localized Repression

The general consensus in the field is that limiting amounts of the transcription factor Dorsal establish dorsal boundaries of genes expressed along the dorsal-ventral (DV) axis of early Drosophila embryos, while repressors establish ventral boundaries. Yet recent studies have provided evidence that repressors act to specify the dorsal boundary of intermediate neuroblasts defective (ind), a gene expressed in a stripe along the DV axis in lateral regions of the embryo. Here we show that a short 12 base pair sequence (“the A-box”) present twice within the ind CRM is both necessary and sufficient to support transcriptional repression in dorsal regions of embryos. To identify binding factors, we conducted affinity chromatography using the A-box element and found a number of DNA-binding proteins and chromatin-associated factors using mass spectroscopy. Only Grainyhead (Grh), a CP2 transcription factor with a unique DNA-binding domain, was found to bind the A-box sequence. Our results suggest that Grh acts as an activator to support expression of ind, which was surprising as we identified this factor using an element that mediates dorsally-localized repression. Grh and Dorsal both contribute to ind transcriptional activation. However, another recent study found that the repressor Capicua (Cic) also binds to the A-box sequence. While Cic was not identified through our A-box affinity chromatography, utilization of the same site, the A-box, by both factors Grh (activator) and Cic (repressor) may also support a “switch-like” response that helps to sharpen the ind dorsal boundary. Furthermore, our results also demonstrate that TGF-β signaling acts to refine ind CRM expression in an A-box independent manner in dorsal-most regions, suggesting that tiers of repression act in dorsal regions of the embryo

Negative regulation of ErbB family receptor tyrosine kinases

Receptors of the EGF receptor or ErbB family of growth factor receptor tyrosine kinases are frequently overexpressed in a variety of solid tumours, and the aberrant activation of their tyrosine kinase activities is thought to contribute to tumour growth and progression. Much effort has been put into developing inhibitors of ErbB receptors, and both antibody and small-molecule approaches have exhibited clinical success. Recently, a number of endogenous negative regulatory proteins have been identified that suppress the signalling activity of ErbB receptors in cells. These include intracellular RING finger E3 ubiquitin ligases such as cbl and Nrdp1 that mediate ErbB receptor degradation, and may include a wide variety of secreted and transmembrane proteins that suppress receptor activation by growth factor ligands. It will be of interest to determine the extent to which tumour cells suppress these pathways to promote their progression, and whether restoration of endogenous receptor-negative regulatory pathways may be exploited for therapeutic benefit