Stress protein (HSP70 family) expression in intertidal benthic organisms: the example of <i>Anthopleura elegantissima</i> (Cnidaria: Anthozoa)

Abstract

Both the physiology and distribution of intertidal organisms are strongly influenced by different kinds of physical stress. Temperature, UV radiation and desiccation in low tide conditions are usually considered the most important physical stresses. These factors impact cell metabolism, and the organism's ability to rapidly adapt to altering environmental conditions sets its tidal distribution limits. The role of the HSP70 protein (stress protein) family in thermal stress responses has been widely demonstrated. Although it has been shown that stress protein expression is a useful tool to quantify part of this physical stress, few studies have been made with different in situ intertidal organisms. To test differences in HSP70 expression under natural conditions in the intertidal environment, we chose a common cnidarian of the eastern Pacific Ocean: the anemone Anthopleura elegantissima. Polyp HSP70 expression depends on the degree of emersion and the extent of physical stress (0.1-3.6 ± 1.5 ng HSP70 µg Protein -1 were registered between fully immersed and fully emersed polyps of the same clone). The time of immersion is reflected in the recovery of polyp HSP70 levels from the high tidal exposure (reaching again as shallower clones express more HSP70 (2.5 ng HSP70 µg P -1 ), than deeper ones (0.1 ng HSP70 µg P -1 ). Also sunny and foggy environmental situations influence the stress response. Anemone clones exposed to the sunny high intertidal zone express more than three times HSP70 (2.2 ng HSP70 µg P -1 ) than those on a foggy high intertidal day (0.6 ng HSP70 µg P -1 ). For A. elegantissima, shrinking of polyps, mucus secretion, sand covering, UV absorbing molecules, and a tight patch structure work concurrently with HSP70 expression to alleviate the effects of physical stress in low tidal emersion.Key words: Anthopleura, stress proteins, HSPs, intertidal stress, temperature RESUMEN: EXPRESIÓN DE LAS PROTEÍNAS DE ESTRÉS (FAMILIA DE LA HSP70) EN ORGANISMOS BENTÓNICOS INTERMAREALES:EL EJEMPLO DE ANTHOPLEURA ELEGANTISSIMA (CNIDARIOS: ANTOZOOS). -Tanto la fisiología como la distribución de los organismos intermareales están muy influenciados por distintos tipos de estrés físico. Temperatura, radiación ultravioleta y desecación en condiciones de bajamar se suelen considerar los estreses físicos más importantes. Dichos factores ejercen su impacto sobre el metabolismo celular, y la capacidad del organismo de adaptarse rápidamente a condiciones ambientales alteradas establece sus límites de distribución mareal. Se ha demostrado de forma general el papel de la familia de proteí-nas HSP70 (proteínas de estrés) en las respuestas al estrés térmico. Aunque se ha demostrado que la expresión de la proteína de estrés es una herramienta útil para cuantificar parte de este estrés físico, se han realizado pocos estudios con diferentes organismos intermareales in situ. Para comprobar diferencias en la expresión de la HSP70 bajo condiciones naturales en el ambiente intermareal, elegimos un cnidario común del océano Pacífic...

The effects of symbiotic state on heterotrophic feeding in the temperate sea anemone Anthopleura elegantissima

“…We believe that sunlight had direct eVects on cnida production in these asymbiotic individuals. Anemones exposed to sunlight invest energy in pigments and enzymatic repair mechanisms as a defense against light Dykens and Shick 1984) and temperature (Snyder and Rossi 2004) damage. Symbiotic anemones we collected from a high-light Weld location, therefore, were accustomed to the high irradiance they subsequently experienced in the experimental tank.…”

Protein, carbohydrate, lipid concentrations and HSP 70–HSP 90 (stress protein) expression over an annual cycle: useful tools to detect feeding constraints in a benthic suspension feeder

“…HSP 70 and 90 expression has been previously reported in cnidarians by others using the same or similar techniques (Miller et al 1992;Sharp et al 1994;Black et al 1995;Fang et al 1997;Sharp et al 1997;Wiens et al 2000;Rossi and Snyder 2001;Snyder and Rossi 2004).…”

“…The high mobility of carbohydrates under food deprivation is well known (Willmer et al 2000), and HSPs are rapidly activated in a thermal stress situation (e.g. Hofmann and Somero 1996;Helmuth and Hofmann 2001), and may quickly reduce their levels when stress ceases (Snyder and Rossi 2004). HSPs may become toxic by binding cellular proteins if continuously expressed at high levels (Feder and Hofmann 1999).…”

“…In situ HSP expression studies have been performed on very few species (e.g. Hofmann and Somero 1995;Helmuth and Hofmann 2001;Rossi and Snyder 2001;Snyder and Rossi 2004). Only very recently the stress protein response has been related directly or indirectly to ecological processes other than heat shock (Minier et al 2000;Rossi and Snyder 2001).…”

“…Hoffman and Somero 1996;Minier et al 2000;Snyder and Rossi 2004). It is known that HSPs are important for organisms that under natural conditions encounter high physical stress such as temperature shifts.…”