ABSTRACT. To identify genes of potential importance to alkalinity tolerance, RNA sequencing (RNA-Seq) was performed to survey gill transcriptome profiles from freshwater (FW) and alkaline water (AW) exposed Nile tilapia (Oreochromis niloticus). A total of 22,724,036 (AW)/16,461,040 (FW) single-end reads were generated in which 20,304,348 (AW)/14,681,290 (FW) reads (90.0/89.72%) were aligned to the reference genome. Differential expression analysis revealed 302 up-regulated and 193 downregulated genes between AW-and FW-exposed fish. These differentially expressed genes were enriched in several Gene Ontology (GO) terms related to "stress response", "heme binding", and "carbonate dehydratase activity". Meanwhile, significant KEGG pathways were enriched in energy metabolism, including nitrogen and sulfur metabolism. These results demonstrate the response of Nile tilapia exposed to alkaline-water and might provide valuable information to further understand the molecular mechanisms of adaptation of fish to alkaline environments.

ABSTRACT. MAT1 (ménage à trois 1), an assembly factor and targeting subunit of the CDK-dependent kinase (CAK), can regulate the cell cycle, transcription, and DNA repair. This study was intended to investigate the role of MAT1 in the reproductive maturation of black tiger shrimp (Penaeus monodon). In this study, the P. monodon MAT1 (PmMAT1) observed in ovaries. In the ovaries, the PmMAT1 gene was continuously but differentially expressed during the maturation stages. Comparative analyses of MAT1, CDK7, and cyclin H in the CAK complex of P. monodon indicated that the expression of CDK7 and cyclin H coincided with that of MAT1 during the ovary maturation stages. Serotonin (5-HT) injection promoted the expression level of PmMAT1 in the ovaries of shrimp at 6-48 h post-injection. These results indicate that PmMat1 plays a prominent role in the process of ovarian maturation.