Development of individual based models in marine fisheries research

Modern fisheries stock assessment models are evolving towards increasing complexity (Maunder & Punt, 2013), with capabilities to assimilate a diverse suite of data and incorporate spatial structure (Cadrin & Secor, 2009) and the influence of environmental factors. As the number of such efforts increase, the behavior and performance of these complex models need to be tested to assure a scientific basis for fishery management. These efforts to test the plethora of models have resulted in extensive simulation studies have been conducted to examine the robustness of the models and incorporate various process and measurement errors, including data quality and quantity (Chen et al., 2003), mis-specifications of life history parameters (Deroba & Schueller, 2013; Punt, 2003), fishery characteristics (Cope & Punt, 2011), and violations of model assumptions (Guan, Cao, Chen, & Cieri, 2013)

How oceanography influences Fishery Biology? - A Case of distribution differences in carnivorous and planktivorous fishes along the Coastal Waters of Eastern Arabian Sea In: ICAR Sponsored Winter School on Recent Advances in Fishery Biology Techniques for Biodiversity Evaluation and Conservation, 1-21 December 2018, Kochi.

Understanding the link between physical oceanographic events and seasonality in catch composition is a critical component in the accurate assessment of climate change impacts in context of fisheries. This remains elusive owing to the lack of synoptic-level datasets on the relevant oceanographic variables. The advent of satellite remote sensing that can measure oceanographic variables at high spatial and temporal resolution has helped to address this challenge. Prior studies have communicated the puzzling dominance of carnivores (fish groups) in North East Arabian Sea (NEAS) whereas planktivores appear to thrive in South East Arabian Sea (SEAS). The study attempts to address this conundrum by taking cues from the influence of oceanographic forcing upon seasonal trends in catch composition using remotely-sensed oceanographic variables and mean standardized catch. The anoxic conditions associated with intense seasonal upwelling in SEAS waters leads to the reduction in the vertical extent of demersal carnivore habitats. The demersal habitats in NEAS waters have a higher likelihood of entraining oxygen rich (>0.5 ml/L) water column when compared with its southern counterpart especially from August to November. Moreover, NEAS waters cater to the nutritional requirements of juvenile demersal carnivore population as it supports primary production both during summer and winter monsoon months. The perpetual presence of chlorophyll biomass allows for the persistence of a prey base that maximizes the likelihood of demersal adult population being well-fed. The poleward directed West India Coastal Current facilitates the passive drift of juveniles towards productive and oxygen rich habitats in NEAS waters. For demersal/pelagic carnivores that undergo recruitment over a long span of time (> 6 months), NEAS waters provide the best spawning ground capable of meeting their long-term nutritional demands. Pelagic planktivores thrive in SEAS, where seasonal upwelling supported primary production remains the norm, owing to their relatively short recruitment span (< 4 months). Unlike SEAS, NEAS waters are found to provide suitable environment geared towards the successful larval recruitment, sustenance and survival of the demersal carnivore group. This could act as a forcing function in driving the annual catch composition of landing data registered in NEAS waters toward carnivore spectrum

Implications of Extreme Climatic Events on Marine Fisheries Sector

Implications of Extreme Climatic Events on Marine Fisheries Secto

Evaluation of A2BP1 as an Obesity Gene

OBJECTIVE-A genome-wide association study (GWAS) in Pima Indians (n = 413) identified variation in the ataxin-2 binding protein 1 gene (A2BP1) that was associated with percent body fat. On the basis of this association and the obese phenotype of ataxin-2 knockout mice, A2BP1 was genetically and functionally analyzed to assess its potential role in human obesity. RESEARCH DESIGN AND METHODS-Variants spanning A2BP1 were genotyped in a population-based sample of 3,234 full-heritage Pima Indians, 2,843 of whom were not part of the initial GWAS study and therefore could serve as a sample to assess replication. Published GWAS data across A2BP1 were additionally analyzed in French adult (n = 1,426) and children case/control subjects (n = 1,392) (Meyre et al. Nat Genet 2009;41:157-159). Selected variants were genotyped in two additional samples of Caucasians (Amish, n = 1,149, and German children case/control subjects, n = 998) and one additional Native American (n = 2,531) sample. Small interfering RNA was used to knockdown A2bp1 message levels in mouse embryonic hypothalamus cells. RESULTS-No single variant in A2BP1 was reproducibly associated with obesity across the different populations. However, different variants within intron 1 of A2BP1 were associated with BMI in full-heritage Pima Indians (rs10500331, P = 1.9 x 10(-7)) and obesity in French Caucasian adult (rs4786847, P = 1.9 x 10(-10)) and children (rs8054147, P = 9.2 x 10(-6)) case/control subjects. Reduction of A2bp1 in mouse embryonic hypothalamus cells decreased expression of Atxn2, Insr, and Mc4r. CONCLUSIONS-Association analysis suggests that variation in A2BP1 influences obesity, and functional studies suggest that A2BP1 could potentially affect adiposity via the hypothalamic MC4R pathway. Diabetes 59:2837-2845, 201

The Lsm1-7/Pat1 complex binds to stress-activated mRNAs and modulates the response to hyperosmotic shock

RNA-binding proteins (RBPs) establish the cellular fate of a transcript, but an understanding of these processes has been limited by a lack of identified specific interactions between RNA and protein molecules. Using MS2 RNA tagging, we have purified proteins associated with individual mRNA species induced by osmotic stress, STL1 and GPD1. We found members of the Lsm1-7/Pat1 RBP complex to preferentially bind these mRNAs, relative to the non-stress induced mRNAs, HYP2 and ASH1. To assess the functional importance, we mutated components of the Lsm1-7/Pat1 RBP complex and analyzed the impact on expression of osmostress gene products. We observed a defect in global translation inhibition under osmotic stress in pat1 and lsm1 mutants, which correlated with an abnormally high association of both non-stress and stress-induced mRNAs to translationally active polysomes. Additionally, for stress-induced proteins normally triggered only by moderate or high osmostress, in the mutants the protein levels rose high already at weak hyperosmosis. Analysis of ribosome passage on mRNAs through co-translational decay from the 5' end (5P-Seq) showed increased ribosome accumulation in lsm1 and pat1 mutants upstream of the start codon. This effect was particularly strong for mRNAs induced under osmostress. Thus, our results indicate that, in addition to its role in degradation, the Lsm1-7/Pat1 complex acts as a selective translational repressor, having stronger effect over the translation initiation of heavily expressed mRNAs. Binding of the Lsm1-7/Pat1p complex to osmostress-induced mRNAs mitigates their translation, suppressing it in conditions of weak or no stress, and avoiding a hyperresponse when triggered

An mRNA decapping mutant deficient in P body assembly limits mRNA stabilization in response to osmotic stress

Yeast is exposed to changing environmental conditions and must adapt its genetic program to provide a homeostatic intracellular environment. An important stress for yeast in the wild is high osmolarity. A key response to this stress is increased mRNA stability primarily by the inhibition of deadenylation. We previously demonstrated that mutations in decapping activators (edc3∆ lsm4∆C), which result in defects in P body assembly, can destabilize mRNA under unstressed conditions. We wished to examine whether mRNA would be destabilized in the edc3∆ lsm4∆C mutant as compared to the wild-type in response to osmotic stress, when P bodies are intense and numerous. Our results show that the edc3∆ lsm4∆C mutant limits the mRNA stability in response to osmotic stress, while the magnitude of stabilization was similar as compared to the wild-type. The reduced mRNA stability in the edc3∆ lsm4∆C mutant was correlated with a shorter PGK1 poly(A) tail. Similarly, the MFA2 mRNA was more rapidly deadenylated as well as significantly stabilized in the ccr4∆ deadenylation mutant in the edc3∆ lsm4∆C background. These results suggest a role for these decapping factors in stabilizing mRNA and may implicate P bodies as sites of reduced mRNA degradation

Rational Extension of the Ribosome Biogenesis Pathway Using Network-Guided Genetics

Gene networks are an efficient route for associating candidate genes with biological processes. Here, networks are used to discover more than 15 new genes for ribosomal subunit maturation, rRNA processing, and ribosomal export from the nucleus

Sequence context outside the target region influences the effectiveness of miR-223 target sites in the RhoB 3′UTR

MicroRNAs (miRNAs) are 21–22 nucleotide regulatory small RNAs that repress message translation via base-pairing with complementary sequences in the 3′ untranslated region (3′UTR) of targeted transcripts. To date, it is still difficult to find a true miRNA target due to lack of a clear understanding of how miRNAs functionally interact with their targeted transcripts for efficient repression. Previous studies have shown that nucleotides 2 to 7 at the 5′-end of a mature miRNA, the ‘seed sequence’, can nucleate miRNA/target interactions. In the current study, we have validated that the RhoB mRNA is a bona fide miR-223 target. We have analyzed the functional activities of two miR223-binding sites within the RhoB 3′UTR. We find that the two miR-223 target sites in the RhoB 3′UTR contribute differentially to the total repression of RhoB translation. Moreover, we demonstrate that some AU-rich motifs located upstream of the distal miRNA-binding site enhance miRNA function, independent of the miRNA target sequences being tested. We also demonstrate that the AU-rich sequence elements are polar, and do not affect the activities of miRNAs whose sites lie upstream of these elements. These studies provide further support for the role of sequences outside of miRNA target region influencing miRNA function

Novel conserved domains in proteins with predicted roles in eukaryotic cell-cycle regulation, decapping and RNA stability

BACKGROUND: The emergence of eukaryotes was characterized by the expansion and diversification of several ancient RNA-binding domains and the apparent de novo innovation of new RNA-binding domains. The identification of these RNA-binding domains may throw light on the emergence of eukaryote-specific systems of RNA metabolism. RESULTS: Using sensitive sequence profile searches, homology-based fold recognition and sequence-structure superpositions, we identified novel, divergent versions of the Sm domain in the Scd6p family of proteins. This family of Sm-related domains shares certain features of conventional Sm domains, which are required for binding RNA, in addition to possessing some unique conserved features. We also show that these proteins contain a second previously uncharacterized C-terminal domain, termed the FDF domain (after a conserved sequence motif in this domain). The FDF domain is also found in the fungal Dcp3p-like and the animal FLJ22128-like proteins, where it fused to a C-terminal domain of the YjeF-N domain family. In addition to the FDF domains, the FLJ22128-like proteins contain yet another divergent version of the Sm domain at their extreme N-terminus. We show that the YjeF-N domains represent a novel version of the Rossmann fold that has acquired a set of catalytic residues and structural features that distinguish them from the conventional dehydrogenases. CONCLUSIONS: Several lines of contextual information suggest that the Scd6p family and the Dcp3p-like proteins are conserved components of the eukaryotic RNA metabolism system. We propose that the novel domains reported here, namely the divergent versions of the Sm domain and the FDF domain may mediate specific RNA-protein and protein-protein interactions in cytoplasmic ribonucleoprotein complexes. More specifically, the protein complexes containing Sm-like domains of the Scd6p family are predicted to regulate the stability of mRNA encoding proteins involved in cell cycle progression and vesicular assembly. The Dcp3p and FLJ22128 proteins may localize to the cytoplasmic processing bodies and possibly catalyze a specific processing step in the decapping pathway. The explosive diversification of Sm domains appears to have played a role in the emergence of several uniquely eukaryotic ribonucleoprotein complexes, including those involved in decapping and mRNA stability