Analysis of ontogenetic growth trends in two marine Antarctic bivalves Yoldia eightsi and Laternula elliptica: Implications for sclerochronology

There is an increasing use of marine species as paleoclimate recorders for the marine realm. These archives provide novel baseline records of past oceanographic variability in regions devoid of instrumental observations. Here we report results of a study of the ontogenetic growth pattern of two Antarctic marine bivalve molluscs: Yoldia eightsi and Laternula elliptica from West Antarctic Peninsula populations using negative exponential detrending technique and multi-taper method spectral analysis. Our data show the growth of both Y. eightsi and L. elliptica follow a general negative exponential trend over their longevity. However, our analyses also identified an innate 9.06 year periodic endogenous growth rhythm in the growth increment pattern of Y. eightsi and two innate periodic growth rhythms, 5 and 6.6 year period, were found in L. elliptica. We hypothesize that the Y. eightsi endogenous growth rhythm may be related to the reallocation of energetic resources between somatic growth and gametogenesis although more biological data are required to test this hypothesis. Further work into L. elliptica biology is required to understand the possible meaning of the innate growth rhythms found for this species. The identification growth rhythms is important not only for their biological significance but also in sclerochronological analysis because of their importance in developing paleoenvironmental reconstructions

Reviews and syntheses: A framework to observe, understand and project ecosystem response to environmental change in the East Antarctic Southern Ocean

Abstract. Systematic long-term studies on ecosystem dynamics are largely lacking from the East Antarctic Southern Ocean, although it is well recognized that they are indispensable to identify the ecological impacts and risks of environmental change. Here, we present a framework for establishing a long-term cross-disciplinary study on decadal timescales. We argue that the eastern Weddell Sea and the adjacent sea to the east, off Dronning Maud Land, is a particularly well suited area for such a study, since it is based on findings from previous expeditions to this region. Moreover, since climate and environmental change have so far been comparatively muted in this area, as in the eastern Antarctic in general, a systematic long-term study of its environmental and ecological state can provide a baseline of the current situation, which will be important for an assessment of future changes from their very onset, with consistent and comparable time series data underpinning and testing models and their projections. By establishing an Integrated East Antarctic Marine Research (IEAMaR) observatory, long-term changes in ocean dynamics, geochemistry, biodiversity, and ecosystem functions and services will be systematically explored and mapped through regular autonomous and ship-based synoptic surveys. An associated long-term ecological research (LTER) programme, including experimental and modelling work, will allow for studying climate-driven ecosystem changes and interactions with impacts arising from other anthropogenic activities. This integrative approach will provide a level of long-term data availability and ecosystem understanding that are imperative to determine, understand, and project the consequences of climate change and support a sound science-informed management of future conservation efforts in the Southern Ocean. </jats:p

Phosphorylation of serine 225 in hepatitis C virus NS5A regulates protein-protein interactions.

Hepatitis C virus (HCV) non-structural protein 5A (NS5A) is a phosphoprotein that plays key, yet poorly defined, roles in both virus genome replication and virion assembly/release. It has been proposed that differential phosphorylation could act as a switch to regulate the various functions of NS5A, however the mechanistic details of the role of this post-translational modification in the virus life cycle remains obscure. We previously reported (Ross-Thriepland et al, 2015) a role for phosphorylation at serine 225 (S225) of NS5A in the regulation of JFH-1 (genotype 2a) genome replication. A phosphoablatant (S225A) mutation resulted in a 10-fold reduction in replication and a perinuclear restricted distribution of NS5A, whereas the corresponding phosphomimetic mutation (S225D) had no phenotype. To determine the molecular mechanisms underpinning this phenotype we conducted a label-free proteomics approach to identify cellular NS5A interaction partners. This analysis 30 revealed that the S225A mutation disrupted the interactions of NS5A with a number of cellular proteins, in particular the nucleosome assembly protein 1-like protein 1 (NAP1L1), bridging integrator 1 (Bin1, also known as Amphiphysin II) and vesicle associated membrane protein-associated protein A (VAP-A). These interactions were validated by immunoprecipitation/western blotting, immunofluorescence and proximity ligation assay. Importantly, siRNA-mediated knockdown of NAP1L1, Bin1 or VAP-A impaired viral genome replication and recapitulated the perinuclear redistribution of NS5A seen in the S225A mutant. These results demonstrate that S225 phosphorylation regulates the interactions of NS5A with a defined subset of cellular proteins. Furthermore, these interactions regulate both HCV genome replication and the subcellular localisation of replication complexes. IMPORTANCE Hepatitis C virus is an important human pathogen. The viral nonstructural 5A protein (NS5A) is the target for new antiviral drugs. NS5A has multiple functions during the virus life cycle, but the biochemical details of these roles remain obscure. NS5A is known to be phosphorylated by cellular protein kinases, and in this study, we set out to determine whether this modification is required for the binding of NS5A to other cellular proteins. We identified 3 such proteins and show that they interacted only with NS5A that was phosphorylated on a specific residue. Furthermore, these proteins were required for efficient virus replication and the ability of NS5A to spread throughout the cytoplasm of the cell. Our results help to define the function of NS5A and may contribute to an understanding of the mode of action of the highly potent antiviral drugs that are targeted to NS5A

Reviews and syntheses: A framework to observe, understand, and project ecosystem response to environmental change in the East Antarctic Southern Ocean

Systematic long-term studies on ecosystem dynamics are largely lacking for the East Antarctic Southern Ocean, although it is well recognized that such investigations are indispensable to identify the ecological impacts and risks of environmental change. Therefore, here we develop a framework for establishing a long-term cross-disciplinary study and argue why the eastern Weddell Sea and the easterly adjacent sea off Dronning Maud Land (WSoDML) is a well suited area for such an initiative. As in the Eastern Antarctic in general, climate and environmental change have so far been comparatively muted in this area. A systematic long-term study of its environmental and ecological state can thus provide a baseline of the current situation, an assessment of future changes, and sound data can act as a model to develop and calibrate projections. Establishing a long-term observation (LTO) and long-term ecological research (LTER) programme now would allow the study of climate-driven ecosystem changes and interactions with impacts arising from other anthropogenic activities, from their very onset. Through regular autonomous and ship-based LTO activities, changes in ocean dynamics, geochemistry, biodiversity and ecosystem functions and services can be systematically explored and mapped. This observational work should be accompanied by targeted LTER efforts, including experimental and modelling studies. This approach will provide a level of long-term data availability and ecosystem understanding that are imperative to determine, understand, and project the consequences of climate change and support a sound science-informed management of future conservation efforts in the Southern Ocean

A Bioassay and Histopathology Study on the Effects of Nosema Locustae in Melanoplus Sanguinipes and Melanoplus Bivittatus

The purpose of this masters thesis was to compare the virulence and pathogenicity of N. locustae in two grasshopper species (M. sanguinipes and M. bivittatus) that naturally differed in their sensitivity and susceptibility to this pathogen. In order to accomplish this task, bioassay studies and histopathological studies at the light microscopic and ultrastructural level were conducted using these two grasshopper species. It is hoped that by understanding why N. locustae is more virulent and pathogenic in one grasshopper species and less virulent and pathogenic in another, we may then be able to better understand how this microsporidian damages its hosts. Understanding the normal mechanism for pathogenicity may eventually enable us to improve the virulency of N. locustae and thereby enhance its effectiveness in the field

An evaluation of municipal wastewater treatment systems for the production of non-restricted irrigation water

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