192 research outputs found
In situ associations between marine photosynthetic picoeukaryotes and potential parasites - a role for fungi?
Photosynthetic picoeukaryotes (PPEs) are important components of the marine picophytoplankton community playing a critical role in CO2 fixation but also as bacterivores, particularly in the oligotrophic gyres. Despite an increased interest in these organisms and an improved understanding of the genetic diversity of this group, we still know little of the environmental factors controlling the abundance of these organisms. Here, we investigated the quantitative importance of eukaryotic parasites in the free-living fraction as well as in associations with PPEs along a transect in the South Atlantic. Using tyramide signal amplification-fluorescence in situ hybridization (TSA-FISH), we provide quantitative evidence of the occurrence of free-living fungi in open ocean marine systems, while the Perkinsozoa and Syndiniales parasites were not abundant in these waters. Using flow cytometric cell sorting of different PPE populations followed by a dual-labelled TSA-FISH approach, we also demonstrate fungal associations, potentially parasitic, occurring with both pico-Prymnesiophyceae and pico-Chrysophyceae. These data highlight the necessity for further work investigating the specific role of marine fungi as parasites of phytoplankton to improve understanding of carbon flow in marine ecosystems
Resilience of SAR11 bacteria to rapid acidification in the high latitude open ocean
Ubiquitous SAR11 Alphaproteobacteria numerically dominate marine planktonic communities. Because they are excruciatingly difficult to cultivate, there is comparatively little known about their physiology and metabolic responses to long- and short- term environmental changes. As surface oceans take up anthropogenic, atmospheric CO2, the consequential process of ocean acidification could affect the global biogeochemical significance of SAR11. Shipping accidents or inadvertent release of chemicals from industrial plants can have strong short-term local effects on oceanic SAR11. This study investigated the effect of 2.5 fold acidification of seawater on the metabolism of SAR11 and other heterotrophic bacterioplankton along a natural temperature gradient crossing the North Atlantic Ocean, Norwegian and Greenland Seas. Uptake rates of the amino acid leucine by SAR11 cells as well as other bacterioplankton remained similar to controls despite an instant ∼50% increase in leucine bioavailability upon acidification. This high physiological resilience to acidification even without acclimation, suggests that open ocean dominant bacterioplankton are able to cope even with sudden and therefore more likely with long-term acidification effects
Introducción de la perspectiva de género en el Grado de Trabajo Social
Introducir la perspectiva de género en la docencia universitaria significa analizar situaciones de desigualdad que se pueden dar durante el proceso de enseñanza-aprendizaje. Estamos en los inicios de un proceso largo y en el que participan un movimiento amplio formado por profesorado universitario y personal investigador que juegan un papel importante para reducir o eliminar los sesgos de género en el proceso de formación para combatir la discriminación sexual y la desigualdad de género. La Universidad de Alicante ha desarrollado un ‘Plan de Igualdad de Oportunidades entre Mujeres y Hombres’ y ha creado una Red de Investigación en Docencia Universitaria “Universidad, Docencia, Género e Igualdad” en el marco del proyecto de Redes de investigación desde el Vicerrectorado de Estudios, Formación y Calidad para abordar la cuestión de género en el ámbito universitario. Siguiendo esta línea, desde el Departamento de Trabajo Social presentamos los resultados obtenidos en la red: ‘REDGITS – Red de Estudios de la Docencia en Género e Internacionalización en Trabajo Social’, con el fin de analizar y estudiar la introducción de la perspectiva de género en el Grado en Trabajo Social desarrollando indicadores y recomendaciones para ello
STT4SG-350: A Speech Corpus for All Swiss German Dialect Regions
We present STT4SG-350 (Speech-to-Text for Swiss German), a corpus of Swiss
German speech, annotated with Standard German text at the sentence level. The
data is collected using a web app in which the speakers are shown Standard
German sentences, which they translate to Swiss German and record. We make the
corpus publicly available. It contains 343 hours of speech from all dialect
regions and is the largest public speech corpus for Swiss German to date.
Application areas include automatic speech recognition (ASR), text-to-speech,
dialect identification, and speaker recognition. Dialect information, age
group, and gender of the 316 speakers are provided. Genders are equally
represented and the corpus includes speakers of all ages. Roughly the same
amount of speech is provided per dialect region, which makes the corpus ideally
suited for experiments with speech technology for different dialects. We
provide training, validation, and test splits of the data. The test set
consists of the same spoken sentences for each dialect region and allows a fair
evaluation of the quality of speech technologies in different dialects. We
train an ASR model on the training set and achieve an average BLEU score of
74.7 on the test set. The model beats the best published BLEU scores on 2 other
Swiss German ASR test sets, demonstrating the quality of the corpus
Quantum chemical DFT and spectroscopic UV-Vis-NIR analysis of a series of push-pull oligothiophenes end capped by amino-cyanovinyl groups
A series of push-pull chromophores built around thiophene-based -conjugating spacers and
bearing various types of amino-donors and cyanovinyl-acceptors have been analyzed by means of UV-Vis-
NIR spectroscopic measurements. Density functional theory (DFT) calculations have also been performed
to help the assignment of the most relevant electronic features and to derive useful information about the
molecular structure of these NLO-phores. The effects of the donor/acceptor substitution in the electronic
and molecular properties of the -conjugated spacer have been addressed. The effectiveness of the
intramolecular charge transfer (ICT) has also been tested as a function of the nature of the end groups (i.e.,
electron-donating or electron-withdrawing capabilities).Research at the University of Málaga was supported by the Ministerio de Educación y Ciencia (MEC) of
Spain through project CTQ2006-14987-C02-01, and by the Junta de Andalucía for funding our FQM-
0159 scientific group. J.C. is grateful to the Ministerio de Ciencia y Tecnología of Spain for a Ramón y
Cajal position of Chemistry at the University of Málaga. M.C.R.D. is also grateful to the Ministerio de
Educación y Ciencia of Spain for a personal grant. The group at the University of Minho acknowledges
the Foundation for Science and Technology (Portugal) for financial support through Centro de Química
(UM) and through POCTI, FEDER (ref. POCTI/QUI/37816/2001). M. Manuela M. Raposo and A.
Maurício C. Fonseca are also grateful to Professor G. Kirsch from University of Metz (France) for his
collaboration
An Overview of Recent Changes in the Global Maritime Distress and Safety System Regarding Maritime Mobile Satellite Service
For a long time, Inmarsat satellite system was the only maritime mobile satellite service provider when Global Maritime Distress and Safety System (GMDSS) is concerned. This satellite system has different generations of its satellites providing a wide range of services and applications. In 2018, its services related to the GMDSS have migrated to a newer generation of satellites. This satellites’ services migration is systematically discussed and analysed in this paper in order to familiarize the readers with its effects on the safety of navigation. Furthermore, Inmarsat system announced a new service called Inmarsat Fleet Safety which will incorporate and provide all functional requirements for the GMDSS which are currently provided by Inmarsat-C and Inmarsat Fleet 77 terminals. However, in 2018 a new satellite system called Iridium has been recognized as a mobile satellite communication services provider in the GMDSS. Accordingly, this system and its capabilities are also introduced and briefly described in this paper. In addition, authors have discussed impacts of the introduction of the new satellite system as a service provider in the GMDSS and addressed several emphasized issues related to this GMDSS modernization
Temporal shifts in prokaryotic metabolism in response to organic carbon dynamics in the mesopelagic ocean during an export event in the Southern ocean
As the major term in downward organic carbon flux attenuation, determining prokaryotic metabolism over depth in the mesopelagic ocean is crucial for constraining the efficiency of the gravitational biological carbon pump (BCP). We hypothesize that the enhancement of particulate organic carbon (POC) concentrations in the mesopelagic twilight zone during export events leads to a temporally dynamic prokaryotic metabolic response, which likely has consequences for the efficiency of the BCP. We tested this hypothesis by making repeated measurements of leucine assimilation and leucine respiration at in situ concentrations over six depths throughout the upper 500 m of the water column during the collapse of a large-scale Southern Ocean spring diatom bloom. Rates of prokaryotic leucine assimilation were used to indicate levels of prokaryotic heterotrophic production, and leucine assimilation efficiency (LAE; the proportion of leucine used for growth versus respiration) was taken as an indicator of prokaryotic growth efficiency. Thus, relative shifts in LAE are indicative of shifts in rates of prokaryotic production relative to respiration. The flux of POC through the oceans’ interior led to a dynamic prokaryotic response, characterized by a temporary elevation in mesopelagic prokaryote leucine assimilation rates, LAE and prokaryotic abundance. By the final measurement these changes had already begun to revert, despite POC concentrations still being enriched. As hypothesized, our data revealed distinctions in the phases of the mesopelagic system, likely due to an evolution in bulk prokaryotic metabolic status and the amount and composition of organic matter available. This indicates that estimating ocean carbon sequestration during export events necessitates a time course of measurements throughout the period of POC downward flux. Our findings also revealed distinctions in the ecophysiological prokaryotic responses to substrate regimes between the surface mixed layer and the mesopelagic. Specifically, in the latter in situ leucine concentrations appeared more significant in controlling prokaryote metabolism than POC concentration, and were more closely related to per cell leucine assimilation, than respiration. Whereas, in the mixed layer, the concentration of in situ leucine did not seem to drive rates of its assimilation, rather POC concentration was a strong negative driver of cell specific leucine respiration. These findings are suggestive of stronger levels of energy limitation in the deeper ocean. We surmised that ocean regions with sporadic substrate supply to the mesopelagic are likely to experience stronger energy limitation which favors prokaryotic respiration over production
ATP hydrolysis by the viral RNA sensor RIG-I prevents unintentional recognition of self-RNA
The cytosolic antiviral innate immune sensor RIG-I distinguishes 5' tri- or diphosphate containing viral double-stranded (ds) RNA from self-RNA by an incompletely understood mechanism that involves ATP hydrolysis by RIG-I's RNA translocase domain. Recently discovered mutations in ATPase motifs can lead to the multi-system disorder Singleton-Merten Syndrome (SMS) and increased interferon levels, suggesting misregulated signaling by RIG-I. Here we report that SMS mutations phenocopy a mutation that allows ATP binding but prevents hydrolysis. ATPase deficient RIG-I constitutively signals through endogenous RNA and co-purifies with self-RNA even from virus infected cells. Biochemical studies and cryo-electron microscopy identify a 60S ribosomal expansion segment as a dominant self-RNA that is stably bound by ATPase deficient RIG-I. ATP hydrolysis displaces wild-type RIG-I from this self-RNA but not from 5' triphosphate dsRNA. Our results indicate that ATP-hydrolysis prevents recognition of self-RNA and suggest that SMS mutations lead to unintentional signaling through prolonged RNA binding
ATP hydrolysis by the viral RNA sensor RIG-I prevents unintentional recognition of self-RNA
The cytosolic antiviral innate immune sensor RIG-I distinguishes 5' tri- or diphosphate containing viral double-stranded (ds) RNA from self-RNA by an incompletely understood mechanism that involves ATP hydrolysis by RIG-I's RNA translocase domain. Recently discovered mutations in ATPase motifs can lead to the multi-system disorder Singleton-Merten Syndrome (SMS) and increased interferon levels, suggesting misregulated signaling by RIG-I. Here we report that SMS mutations phenocopy a mutation that allows ATP binding but prevents hydrolysis. ATPase deficient RIG-I constitutively signals through endogenous RNA and co-purifies with self-RNA even from virus infected cells. Biochemical studies and cryo-electron microscopy identify a 60S ribosomal expansion segment as a dominant self-RNA that is stably bound by ATPase deficient RIG-I. ATP hydrolysis displaces wild-type RIG-I from this self-RNA but not from 5' triphosphate dsRNA. Our results indicate that ATP-hydrolysis prevents recognition of self-RNA and suggest that SMS mutations lead to unintentional signaling through prolonged RNA binding
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