Background Selected Biomarkers; In Vivo And In Situ Applications

I. GENERAL INTRODUCTION

1.1. Background

The term of biomarker has been obtaining intriguing attention, although it has been defined in various meaning thereby the clear definition is rather vague Schlenk 1999. The National Academy of Science in the USA has defined the term of biomarker as a xenobiotically-induced variation in cellular or biochemical components or processes, structures, or functions that is measurable in a biological system or sample NRC 1987. Moreover, Walker et al. 2001 has defined biomarker as any biological response to an environmental chemical at the individual level or below demonstrating a departure from the normal status. Thus, biochemical, physiological, histological, morphological and behavioral measurements are to be considered as biomarkers. Rather similar meaning of the biomarker definition has been proposed by Depledge 1993 emphasized on the matter of measurement and the purpose of biomarkers in screening test and monitoring in fields. The definition is biochemical, cellular, physiological or behavioural variations that can be measured in tissue or body fluid samples or at the level of whole organisms to provide evidence of exposure andor effects from one or more contaminants. The last two definitions have attempted to restrict the term of biomarker that merely addressed to biological responses at individual level. The limitation of biomarker definition had been widened and modified to the level of population, community and ecosystem as illustrated by Adams Adams 1990. Accordingly, Walker et al. 2001 had termed the responses at higher organizational levels – population, community and ecosystem – as a bioindicator. On the other hand McCarty and Munkittrick 1996 broadened the terminology of bioindicator by including biochemical, physiological, or ecological structures or processes which have correlations or causal links to biological effect measured at one or more levels of biological organization. Eventually, the current dissertation uses the working biomarker definition as what proposed by Walker et al. 2001 to pave the way for the discussions of biomarkers appropriately and to avoid overlapping with the terminology that has been used as bioindicator. Many biomarkers have been proposed as a sensitive early warning tool for modern environmental assessment in biomonitoring campaigns, which are ranging from specific to unspecific responses to delineate and record the effect of xenobiotic compounds to living organisms Beliaeff and Burgeot 2002; Sherry 2003; Hagger et al. 2006. As early warning tool, the biomarkers are also efficacious in allowing the initiation of bioremediation strategies before irreversible deleterious damage of ecological consequence are taking place Cajaraville et al. 2000. The specific biomarkers could be possible replacing chemical analysis of the surrounding environment due to their sensitivity, while non-specific biomarkers provide a generalized indication that a living organism may be suffering from stress induced by the presence of xenobiotic compounds Connell et al. 1999. The present dissertation is aimed to provide evidence and explore the use of three selected biomarkers by conducting in vivo and in situ studies. Evident-based concept of the biomarkers originated from blue mussels Mytilus edilus were applied to green mussels, Perna viridis. This effort was addressed to give a rational basis of the use of P. viridis as eco-sentinel organism in effect-based biomonitoring campaign using biomarkers in Indonesian coastal areas since the selected biomarkers such as phagocytic and cholinesterase activities has not been studied yet in the region. Therefore, the studies that discussed in this dissertation will support Indonesian government or environmental managers to manage their marine ecosystem. The three selected biomarkers are considered as a specific biomarker i.e. cholinesterase ChE activity and non-specific biomarkers such as phagocytic activity and siphoning rate in terms of in vivo and hot spot in situ applications. Nevertheless, it should be kept in mind that ChE activity can be inhibited by others contaminants other than organophosphorous and carbamate pesticides such as heavy metals Guilhermino et al. 1998; Tabche et al 1997; Elumalai et al. 2007, PAH Tabche et al. 1997; Akcha et al 2000; Moreira et al. 2004, and detergent Tabche et al. 1997 so that the use of that enzyme as biomarker could be extended Walker et al. 2001. In respect to biological integrity, the three selected biomarkers can be classified into three different levels which are biochemical ChE activity, physiologicalimmunological phagocytic activity and behavioral levels siphoning rate. They also have a potential to be extrapolated to higher level of biological responses such growth and reproduction which may have a relevancy on ecological levels. As consequence, the use of the three different selected biomarkers either in laboratory or field scales may open an opportunity to show how toxicants interfere to biological integrity from biochemical, cellular to behavioral levels that may envisage consequences on ecological levels. Determination of ecological status of such zones which involve biomarkers from different levels of biological integrity as rational basis along with the chemical analysis approach will be meaningful efforts for supporting environment managers and governments in protecting, remediating and managing the environment concerning the anthropogenic activities and the deleterious impacts of wastages.

1.2. Logical Framework