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The Eastern Mediterranean Sea (EMS) is an ultraoligotrophic semi-enclosed sea with low nutrient levels, low primary production rate, impoverished phytoplankton populations and low zooplankton standing stocks. The Cretan Passage in the western Levantine Sea is one of the least explored areas of the EMS. We measured the mesozooplankton biomass, abundance and taxon composition as well as biochemical parameters like Εlectron Τransport System (ETS) activity and Aminoacyl-tRNA Synthetases (AARS) activities in late spring of 2016 (28 March–17 April 2016). The sampling area is influenced by the presence of the permanent Rhodes Cyclonic Gyre east of Crete and a series of smaller permanent or recurrent gyres south of Crete which influence the pathway of the Atlantic Water from the Ionian Sea towards the Levantine Basin at surface and subsurface layers. Mesozooplankton abundance showed slightly increasing values from western to eastern stations of the Cretan Passage and although subsurface maxima were recorded in the 50–100 m layer, the abundance at all stations generally decreased with depth. The community was dominated by copepods at all stations. Juveniles of Clausocalanus followed by juveniles of Oithona and the Oncaea media group (Oncaea waldemari, Oncaea scottodicarloi, Oncaea media) were the most abundant taxa in the upper layer, whereas Mormonilla minor , Haloptilus longicornis and Subeucalanus monachus were mainly found below 100 m. ETS, AARS and biomass for carbon measurements were conducted in the same area for the 0–100 m and 0–500 m layers. ETS was highest at LV13 with 10.56 ± 1.33 μl O 2 h−1 mg protein−1 in 0–500 m and carbon biomass was highest at LV18 with 4.99 mg m−3 in 0–100 m. Lowest values of 4.52 ± 1.46 μl O 2 h−1 mg protein−1 at LV18 in 0–100 m were detected for ETS and 0.91 mg m−3 at LV10 in 0–500 m for carbon biomass. Specific AARS activities showed no significant differences among sites. On the basis of ETS and AARS, we calculated that the zooplankton carbon requirements follow the west to east trend of zooplankton biomass, however, the zooplankton is not well fed and the organisms are living under oligotrophic stress. [ABSTRACT FROM AUTHOR]

Highlights • Wild type AARS is localized in the cytoplasmic region. • The CMT2 N-associated AARS mutant is localized throughout the organelles. • The mutant inhibits differentiation in N1E-115 cells. • Valproic acid reverses the effect of the CMT2 N-associated AARS mutant. Abstract Charcot-Marie-Tooth (CMT) disease is composed of a heterogeneous group of hereditary peripheral neuropathies. The peripheral nervous system primarily comprises two types of cells: neuronal cells and myelinating glial Schwann cells. CMT2 N is an autosomal dominant disease and its responsible gene encodes alanyl-tRNA synthetase (AARS), which is a family of cytoplasmic aminoacyl-tRNA synthetases. CMT2 N is associated with the mutation, including a missense mutation, which is known to decrease the enzymatic activity of AARS, but whether and how its mutation affects AARS localization and neuronal process formation remains to be understood. First, we show that the AARS mutant harboring Asn71-to-Tyr (N71Y) is not localized in cytoplasm. The expression of AARS mutant proteins in COS-7 cells mainly leads to localization into lysosome, whereas the wild type is indeed localized in cytoplasm. Second, in N1E-115 cells as the neuronal cell model, cells expressing the N71Y mutant do not have the ability to grow processes. Third, pretreatment with antiepileptic valproic acid reverses the inhibitory effect of the N71Y mutant on process growth. Taken together, the N71Y mutation of AARS leads to abnormal intracellular localization, inhibiting process growth, yet this inhibition is reversed by valproic acid. [ABSTRACT FROM AUTHOR]

Highlights • Zooplankton migrant biomass and active carbon export doubled in the Alboran Sea WAG. • Diel migrants production in the WAG equaled coastal epipelagic zooplankton production. • Active flux by DVM exceeded the estimated phytoplankton sinking flux within the WAG. • Mesoscale eddies must be included in future models of the biological carbon pump. • The Alboran Sea occidental basin acts as sink of atmospheric carbon in summer. Abstract The distribution of marine productivity in the Alboran Sea responds strongly to its hydrodynamics, shaped by the influence of the Atlantic jet that enters through the Gibraltar Strait. This stream originates an oligotrophic western anticyclonic gyre (WAG) that dominates the western basin of the Alboran Sea. We studied vertical (0–900 m) diel changes in zooplankton biomass, potential respiration (electron transport system activity, ETS) and growth rates (aminoacyl-tRNA synthetases activity, AARS), to assess their variability in relation to the WAG structure. Zooplankton biomass was distributed in distinctive layers and we observed strong diel vertical migrations in the open sea. Diel vertical migrants (DVM) biomass, production and respiration rates doubled within the WAG core. The active carbon flux to mesopelagic waters mediated by DVM, estimated from respiration and mortality at depth, increased from the coast (2.0–5.7 mg C m−2 d−1) towards the gyre core (27.1–76.7 mg C m−2 d−1). The WAG enhanced the carbon export to deep waters, reinforcing the role of the Alboran Sea as sink of atmospheric carbon. [ABSTRACT FROM AUTHOR]

Prokaryotic and eukaryotic cytosolic aminoacyl-tRNA synthetases (aaRSs) are essentially known for their conventional function of generating the full set of aminoacyl-tRNA species that are needed to incorporate each organism's repertoire of genetically-encoded amino acids during ribosomal translation of messenger RNAs. However, bacterial and eukaryotic cytosolic aaRSs have been shown to exhibit other essential nonconventional functions. Here we review all the subcellular compartments that prokaryotic and eukaryotic cytosolic aaRSs can reach to exert either a conventional or nontranslational role. We describe the physiological and stress conditions, the mechanisms and the signaling pathways that trigger their relocation and the new functions associated with these relocating cytosolic aaRS. Finally, given that these relocating pools of cytosolic aaRSs participate to a wide range of cellular pathways beyond translation, but equally important for cellular homeostasis, we mention some of the pathologies and diseases associated with the dis-regulation or malfunctioning of these nontranslational functions. [ABSTRACT FROM AUTHOR]

Abstract: The in situ activity of the enzymes aminoacyl-tRNA synthetases (AARS) and the growth rates of naupliar stages of the planktonic marine copepod Paracartia grani were measured in the laboratory under different temperature and food concentrations. We assessed the effect of these parameters on growth and protein synthesis rates of P. grani nauplii. Growth and protein synthesis rates of P. grani nauplii depended on temperature and food concentration. AARS activity is valid as an index of somatic growth for P. grani nauplii when growth is not limited by food availability. However, the relationship between protein-specific AARS activity and nauplii growth varied according to food availability levels. The degradation of proteins during starvation and/or the ß-oxidation of fatty acids affected the relationship between specific AARS activity and growth rates. The results presented here add to previous studies showing that the AARS activity is a useful tool for estimating somatic growth of this and other key copepod species. Nevertheless, further research is required to elucidate the validity of AARS activity as a universal proxy for growth. [Copyright &y& Elsevier]

Abstract: Despite the abundance of the marine copepod genus Oithona, little is known about its ecology and metabolism, especially regarding its early developmental stages. In this work, we combined two biochemical indices, already used in calanoid copepods, to estimate growth and fitness of Oithona davisae nauplii and copepodites: i) the specific aminoacyl-tRNA synthetases (spAARS) activity (proxy of protein synthesis rate) and ii) the RNA/DNA ratio (indicative of overall metabolic activity). We show here that the two analyses can be performed on the same organisms (samples), thus providing comparable and complementary information about the nauplii physiology. Our experiments provide a first insight into the variability of these parameters on O. davisae early developmental stages, showing that RNA/DNA ratio was more sensitive to starvation than the spAARS activity. A common relationship for nauplii and copepodites was observed between spAARS activity and somatic growth rates; however, RNA/DNA ratio relationships with both somatic growth rates and spAARS activity differed between the naupliar and copepodite stages. The study presented here contributes to the advancement of the study of small copepod nauplii physiology. [Copyright &y& Elsevier]

Abstract: Surface distribution (0–100m) of zooplankton biomass and specific aminoacyl-tRNA synthetases (AARS) activity, as a proxy of structural growth, were assessed during winter 2002 and spring 2004 in the Labrador Sea. Two fronts formed by strong boundary currents, several anticyclonic eddies and a cyclonic eddy were studied. The spatial contrasts observed in seawater temperature, salinity and fluorescence, associated with those mesoscale structures, affected the distributions of both zooplankton biomass and specific AARS activity, particularly those of the smaller individuals. Production rates of large organisms (200–1000μm) were significantly related to microzooplankton biomass (63–200μm), suggesting a cascade effect from hydrography through microzooplankton to large zooplankton. Water masses defined the biomass distribution of the three dominant species: Calanus glacialis was restricted to cold waters on the shelves while Calanus hyperboreus and Calanus finmarchicus were widespread from Canada to Greenland. Zooplankton production was up to ten-fold higher inside anticyclonic eddies than in the surrounding waters. The recent warming tendency observed in the Labrador Sea will likely generate weaker convection and less energetic mesoscale eddies. This may lead to a decrease in zooplankton growth and production in the Labrador basin. [Copyright &y& Elsevier]

In the post genome project era, it is well established that the human genome contains a smaller number of genes than expected. The complexity found in higher organisms can be explained if proteins are multifunctional. Indeed, recent studies are continuing to reveal proteins that are capable of a broad repertoire of functions. A good paradigm for multifunctionality can be found in the amino-acyl tRNA synthetases (aaRSs), an ancient conserved family of proteins. This unique family, which is comprised of 20 different enzymes, is well known for its participation in protein synthesis. Several studies have described numerous examples of these "housekeeping" proteins taking part in extensive critical cellular activities. In this review, we focus on a member of that family, lysyl-tRNA synthetase (LysRS), which has been shown to have a dual functionality. In addition to its contribution to the translation process, LysRS also takes part in the regulation of MITF and USF2 target genes. This phenomenon was first described in mast cells. [ABSTRACT FROM AUTHOR]