Richard Y C Kong has completed his PhD at Monash University, Australia and Postdoctoral research at the University of Hong Kong, Hong Kong SAR, China. He is presently an Associate Professor at the City University of Hong Kong and has published more than 80 papers in internationally referred and reputed journals His research interest is on the development and application of novel DNA-based technologies as risk assessment and bioremediation tools to address problems related to diverse aspects of pollution in the marine environment.
Statement of the Problem: Hypoxia is a pressing environmental problem aff ecting marine and freshwater ecosystems worldwide Hypoxia was found to cause severe reproductive impairments in fi sh, leading to heavy loss of fisheries production over large areas. Laboratory and fi eld studies demonstrated that hypoxia can aff ect both male and female
reproductive systems For example, hypoxia was found to suppress spermatogenesis and decrease sperm motility in carp, impair testicular development and sperm production, and reducing reproductive success in Atlantic croaker retardation of gonadal development has also been observed in the ovaries of female fish numerous reports attributed the reproductive impairments to the suppression of steroidogenic gene expression and alteration of sex hormone production in fish gonads. However, not much is known about the diff erential gene responses in gonads of male and female fi sh to hypoxia stress.The purpose of this study is to investigate the eff ects of hypoxia on the molecular gene responses in the gonads of male and female marine medaka fish.
Methodology: We conducted mRNA transcriptome sequencing and histology on ovaries and testes of hypoxia-exposed marine medaka (Oryzias melastigma) fish, followed by bioinformatics analysis with the view to determining the nature of the molecular responses of male and female fish gonads to hypoxic stress Functional Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Ingenuity Pathway (IPA) analyses were carried out.
Findings: Bioinformatic and functional analyses demonstrated differential and gender-specifi c expression of signaling pathways affecting specifi c biological functions in response to hypoxic stress that correlated with the impairment of reproductive functions in hypoxia-exposed male and female fish.
Conclusion & Significance: Our data provided valuable insights into the diff erential and possible transgenerational molecular responses triggered by chronic hypoxic stress in marine fish.