Date of Publication

11-2018

Document Type

Master's Thesis

Degree Name

Master of Science in Biology

College

College of Science

Department/Unit

Biology

Abstract/Summary

Mud crab Scylla serrata is a commercially important crustacean and an interesting species to study because aside from its male and female sex phenotypes, this species is known to have a sexually-immature adult-sized mud crabs. The biology and market value of Scylla serrata are largely dependent on its sex phenotypes. The increase in the environmental temperature, which is expected to impact habitat temperature, continues to be a threat to the mud crab industry. There have been few studies which show sex-specific effects of temperature stress on some ectotherms, which is why in this study, the differential physiological effects of heat stress in terms of specific proteins, fatty acid profile and HSP70 expression were observed among Scylla serrata sex phenotypes. Adult-sized mud crabs were subjected to heat stress. Temperature for the control group was set at 26±2ºC, while temperature for the experimental group was increased up to 32 ºC at a rate of 2°C/day and was kept for 72 hours. Gill tissue were used for protein and HSP70 expression analysis, while muscle tissue were used for fatty acid analysis. Fatty acid distribution, protein profile, and HSP70 expression and were determined using GCMS, SDS-PAGE, and qRT-PCR, respectively. The general fatty acid composition of S. serrata did not change in response to temperature-stress and sex phenotype. Protein expression of S. serrata also did not display differences among sex phenotype. However, protein expression between control and experimental group was found to be significantly different, with lesser protein expression observed in the experimental group. Protein intensity and HSP70 expression have an approximately moderate correlation. HSP70 expression increased in the experimental group, where less protein expression was observed; and HSP70 expression is consistently low in the control group, where high protein expression was observed. Control and experimental groups are reacting as expected, and this is seen when compared within the same sex phenotype. Overall, the data indicate that the differences in fatty acid, proteins and HSP70 expression of S. serrata is not due to sex phenotype. However, high variation within groups suggest that other possible factors (e.g. genetic variation, site adaptation) obscure the differences observed in the study. Findings in this study will provide information for studies focused on filtering of SNP markers for the sexually-immature adult-sized mud crabs.

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG007365

Keywords

Scylla serrata—Effect of temperature on; Fatty acids; Proteins; Phenotype

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Embargo Period

9-1-2022

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