Judul: Phenotypic plasticity on blood cockle anadara granosa l. as a response to environmental pollution: a case study in coastal waters of Banten
Abstrak: Blood cockle Anadara granosa is a commercial bivalve inhabiting intertidal ecosystem. Coastal waters of Banten such Banten Bay, Bojonegara and Lada Bay, Panimbang are potential areas for blood cockle grow out. Banten Bay is a semi-closed waters facing North Coast of Java. Such industries as coal stockpile, fibre boat manufacturer, chemical industry, steel industry, and many others have been long existed there. Lada Bay geographically is located at the west coast of Banten Province and exposed to Sunda Strait. Anthrophogenic activity is signified by coal fueled power plant, operated in 2009. Anthrophogenic sewages become a problem and lead to environmental pollution. Mercury is one of the pollution source. Inspite of being exposed to polluted habitat, therein blood cockle withstands and reproduce annually. Resistancy to such harmful environmental condition does not take for granted, there must be mechanism controlling the ballance between stress and resistancy. Without controlling factor, blood cockle in both areas is certainly extinct. The factor should be universal for individuals and able to recognize type of stress to be responded briefly. Continuous stress directs the controlling factor to acquintedly recognize and respond it; consequently, the blood cockle may adapt with the condition. The controlling factor, however, gives divergent response to stress, depending on type and level of stress. The factor comprises celluler stress response expressing stress protein and being controlled by one or more gene family. The gene family usually expressed during stress is heat shock protein (Hsp) as cytoprotector. Overexpression of a member of such Hsp gene family as Hsp70 indicates ability of the gene to protect tissue and cell, therefore they withstand to stress. Subsquently, more complex organs are protected from stress. Overexpression of Hsp70 gene is a result of individual habituation to stress. Lack of expression indicates inability of the gene to protect cell, therefore, organism’s resistancy declined. The resistancy defines threshold onto stress-stimulating environmental parameter and provides choice of phenotypic changes as an adaptation strategy. Heterogenous environmental condition in Bojonegara and Panimbang waters may result in various stress responses in blood cockle. Bojonegara blood cockle has long been acquinted with heavy metal-contaminated waters, while Panimbang blood cockle is just exposed to environmental changes. Responses resulted from heterogenous environment are biochemical, physiological, and phenotypic responses. Biochemical and physiological responses appear in the short period of time and become a bottom line for phenotypic plasticity. Phenotypic plasticity occur for longer period of time and those characters are fixed. To support the notion that blood cockle in Bojonegara and Panimbang encounter harmful environment, yet they still survive therein, this research was, thus, aimed at analyzing the ability of the blood cockle to develop phenotypic plasticity through Hsp70 gene expression, and spatial phenotypic variations. Additionally, tolerance limit of the cockle on mercury contamination through histological approach has been also studied. Prior to investigate the existence and characterization of Hsp70 gene, quantitative and qualitative standarization of mRNA materials should be conducted. Standarization comprises application of housekeeping gene as an internal control. The success of this step would facilitate target gene detection. β- actin gene has been used as the housekeeping gene.
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