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J Environ Manage ; 278(Pt 1): 111524, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33126187


Human-induced changes in land and water resources adversely affect global hydrological regimes. Hydrological alteration of the natural flow regime is considered to have a significant damaging and widespread impact on river ecosystems and livelihoods. Therefore, understanding the hydrological alteration of rivers and the potential driving factors affecting such alterations are crucial to effective water resources management. This study analyses the impact of changes in land use, climate, and hydropower development on the hydrological regime of the Srepok River Basin in the Lower Mekong Region. The Lower Mekong Basin (LMB) in Southeast Asia is known for its agriculture, forests, fisheries, wildlife, and diverse natural ecosystems. Historical land use and climate change are quantified (utilising European Space Agency land cover and observed meteorological data) and correlated with the hydrological indicators using the Indicators of Hydrologic Alteration (IHA) software. Moreover, pre and post impacts on the hydrological regime by hydropower development are quantified using the Range of Variability Approach (RAV) in IHA software. The results reveal that land use, rainfall, and temperature affect different aspects of the hydrological regime, with corroborating evidence to support variation among the most correlated IHA and environmental flow component (EFC) parameters with the three drivers. The highest and lowest correlations among the IHA and EFC parameters under each driver are against land use (0.85, -0.83), rainfall (0.78, -0.54), and minimum and max temperatures (0.42, -0.47). Among the parameters, the fall rate has the most significant effect on hydrological alteration of all drivers. Hydropower development in the basin mostly affects the fall rate and reversal. Identifying the connection between these multiple drivers and hydrological alteration could help decision-makers to design more efficient and sustainable water management policies.

Ecossistema , Rios , Ásia Sudeste , Hidrologia , Movimentos da Água
Fish Shellfish Immunol ; 108: 7-13, 2020 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-33217566


Asian seabass, Lates calcarifer farming in Southeast Asia, encounters serious disease challenges caused by Streptococcus agalactiae and Streptococcus iniae. However, a vaccine for disease prevention is not yet available. In this study, we investigated the mucosal and systemic antibody (IgM) response kinetics of the Asian seabass following primary immunization with oil-based formalin-killed vaccines (FKVs) prepared from S. agalactiae and S. iniae (monovalent Sa, monovalent Si, and bivalent Sa-Si) and secondary booster with the respective water-based FKVs. The efficacy of vaccines was subsequently evaluated by an experimental challenge. The results revealed similar antibody response kinetics in both systemic and mucosal systems. However, the immune response in the fish vaccinated with the monovalent vaccines was superior to those fish received the bivalent vaccine in terms of specific antibody titer. The fish that received monovalent vaccines required 1-2 weeks to raise a significant level of specific antibody titer in both systemic and mucosal systems while those vaccinated with bivalent vaccine required three weeks. Following booster at day 21, both systemic and mucosal antibody titers in all vaccinated groups had reached the peak at day 28 and gradually declined in the following weeks but remained significantly higher than control until the end of the experiment (day 63). In the challenge test, both monovalent and bivalent vaccines were found to be highly efficacious, with the relative percentage survival (RPS) ranging from 75 to 85%. In summary, this study explored the 63-days antibody response kinetics (both mucosal and systemic systems) of Asian seabass to monovalent and bivalent inactivated vaccines and confirmed that the combination of S. agalactiae and S. iniae in a single injectable vaccine is possible.

Int J Mol Sci ; 17(5)2016 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-27164098


The giant freshwater prawn, Macrobrachium rosenbergii, a sexually dimorphic decapod crustacean is currently the world's most economically important cultured freshwater crustacean species. Despite its economic importance, there is currently a lack of genomic resources available for this species, and this has limited exploration of the molecular mechanisms that control the M. rosenbergii sex-differentiation system more widely in freshwater prawns. Here, we present the first hybrid transcriptome from M. rosenbergii applying RNA-Seq technologies directed at identifying genes that have potential functional roles in reproductive-related traits. A total of 13,733,210 combined raw reads (1720 Mbp) were obtained from Ion-Torrent PGM and 454 FLX. Bioinformatic analyses based on three state-of-the-art assemblers, the CLC Genomic Workbench, Trans-ABySS, and Trinity, that use single and multiple k-mer methods respectively, were used to analyse the data. The influence of multiple k-mers on assembly performance was assessed to gain insight into transcriptome assembly from short reads. After optimisation, de novo assembly resulted in 44,407 contigs with a mean length of 437 bp, and the assembled transcripts were further functionally annotated to detect single nucleotide polymorphisms and simple sequence repeat motifs. Gene expression analysis was also used to compare expression patterns from ovary and testis tissue libraries to identify genes with potential roles in reproduction and sex differentiation. The large transcript set assembled here represents the most comprehensive set of transcriptomic resources ever developed for reproduction traits in M. rosenbergii, and the large number of genetic markers predicted should constitute an invaluable resource for future genetic research studies on M. rosenbergii and can be applied more widely on other freshwater prawn species in the genus Macrobrachium.

Algoritmos , Decápodes/genética , Reprodução/genética , Análise de Sequência de RNA/métodos , Transcriptoma , Animais , Decápodes/metabolismo , Decápodes/fisiologia , Marcadores Genéticos , Genoma , Anotação de Sequência Molecular/métodos , Polimorfismo de Nucleotídeo Único
Mar Biotechnol (NY) ; 16(2): 161-80, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24122143


A candidate gene approach using type I single nucleotide polymorphism (SNP) markers can provide an effective method for detecting genes and gene regions that underlie phenotypic variation in adaptively significant traits. In the absence of available genomic data resources, transcriptomes were recently generated in Macrobrachium rosenbergii to identify candidate genes and markers potentially associated with growth. The characterisation of 47 candidate loci by ABI re-sequencing of four cultured and eight wild samples revealed 342 putative SNPs. Among these, 28 SNPs were selected in 23 growth-related candidate genes to genotype in 200 animals selected for improved growth performance in an experimental GFP culture line in Vietnam. The associations between SNP markers and individual growth performance were then examined. For additive and dominant effects, a total of three exonic SNPs in glycogen phosphorylase (additive), heat shock protein 90 (additive and dominant) and peroxidasin (additive), and a total of six intronic SNPs in ankyrin repeats-like protein (additive and dominant), rolling pebbles (dominant), transforming growth factor-ß induced precursor (dominant), and UTP-glucose-1-phosphate uridylyltransferase 2 (dominant) genes showed significant associations with the estimated breeding values in the experimental animals (P =0.001-0.031). Individually, they explained 2.6-4.8 % of the genetic variance (R²=0.026-0.048). This is the first large set of SNP markers reported for M. rosenbergii and will be useful for confirmation of associations in other samples or culture lines as well as having applications in marker-assisted selection in future breeding programs.

Estudo de Associação Genômica Ampla/métodos , Palaemonidae/crescimento & desenvolvimento , Palaemonidae/genética , Polimorfismo de Nucleotídeo Único/genética , Locos de Características Quantitativas/genética , Transcriptoma/genética , Animais , Mapeamento Cromossômico , Marcadores Genéticos/genética