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Stress levels over time in the introduced ascidian Styela plicata: the effects of temperature and salinity variations on hsp70 gene expression.

ABSTRACT: Species distribution, abundance, and long-term survival are determined by biotic and abiotic regimes. However, little is known about the importance of these factors in species range expansion. Styela plicata is a solitary ascidian introduced all over the world by ship fouling, including salt marsh habitats, where introduced populations must tolerate high seasonal variations in temperature and salinity. To determine the seasonal stress levels in a salt marsh population of S. plicata, we quantified heat shock protein (hsp70) gene expression using quantitative real-time PCR throughout a 2-year cycle. Results showed that hsp70 expression varied over time, with higher stress levels recorded in summer and winter. Periodic conditions of high temperatures, particularly when coupled with low salinities, increased hsp70 gene expression. Mortality events observed every year around June were concurrent with sharp increases in temperature (>6°C), indicating that drastic changes in abiotic factors may overwhelm the observed stress response mechanisms. Determining the ability of introduced species to cope with stress, and the thresholds above which these mechanisms fail, is fundamental to predict the potential expansion range of introduced species and design efficient containment plans.

SUBMITTER: Pineda MC

PROVIDER: S-EPMC3368029 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature

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Stress levels over time in the introduced ascidian Styela plicata: the effects of temperature and salinity variations on hsp70 gene expression.

Pineda Mari Carmen MC Turon Xavier X López-Legentil Susanna S

Cell stress & chaperones 20120117 4

Species distribution, abundance, and long-term survival are determined by biotic and abiotic regimes. However, little is known about the importance of these factors in species range expansion. Styela plicata is a solitary ascidian introduced all over the world by ship fouling, including salt marsh habitats, where introduced populations must tolerate high seasonal variations in temperature and salinity. To determine the seasonal stress levels in a salt marsh population of S. plicata, we quantifie ...[more]

PMID: 22249790

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Project description:Genetic tools have greatly aided in tracing the sources and colonization history of introduced species. However, recurrent introductions and repeated shuffling of populations may have blurred some of the genetic signals left by ancient introductions. Styela plicata is a solitary ascidian distributed worldwide. Although its origin remains unclear, this species is believed to have spread worldwide by travelling on ship's hulls. The goals of this study were to infer the genetic structure and global phylogeography of S. plicata and to look for present-day and historical genetic patterns. Two genetic markers were used: a fragment of the mitochondrial gene Cytochrome Oxidase subunit I (COI) and a fragment of the nuclear gene Adenine Nucleotide Transporter/ADP-ATP Translocase (ANT). A total of 368 individuals for COI and 315 for ANT were sequenced from 17 locations worldwide. The levels of gene diversity were moderate for COI to high for ANT. The Mediterranean populations showed the least diversity and allelic richness for both markers, while the Indian, Atlantic and Pacific Oceans had the highest gene and nucleotide diversities. Network and phylogenetic analyses with COI and ANT revealed two groups of alleles separated by 15 and 4 mutational steps, respectively. The existence of different lineages suggested an ancient population split. However, the geographic distributions of these groups did not show any consistent pattern, indicating different phylogeographic histories for each gene. Genetic divergence was significant for many population-pairs irrespective of the geographic distance among them. Stochastic introduction events are reflected in the uneven distribution of COI and ANT allele frequencies and groups among many populations. Our results confirmed that S. plicata has been present in all studied oceans for a long time, and that recurrent colonization events and occasional shuffling among populations have determined the actual genetic structure of this species.

Project description:ObjectiveIn search for a unique natural combination of highly active biological components for treatment against colon cancer, we used aqueous extract of Ascidia, Styela plicata (ASCex), a marine invertebrate depending on its richness of high levels of biologically active components as indicated in our previous studies, against rat colon cancer, exploring its underlying mechanisms.MethodsRats chemically initiated for colon cancer were either non-treated or post-treated with highly saturated ASCex for 32 weeks after initiation, other groups of rats were administered ASCex without cancer initiation or served as normal controls.ResultsRats treated with ASCex alone did not show any signs of non-favored health conditions. Treatment with ASCex after cancer initiation has significantly reduced the average incidences, multiplicities and volumes of colon tumors (adenomas and adenocarcinomas) as compared with the non-treated cancer group. ASCex has also significantly reduced the total numbers of aberrant crypt foci (ACF), surrogate biomarkers for colon cancer as compared with the non-treated cancer group. Moreover, anti-proliferative celluar nucular antigen (PCNA) immunohistochemical staining revealed that ASCex exerted significant antiproliferative characteristics in the carcinogen-treated colonic mucosa as compared with its corresponding control. Also, treatment with ASCex has markedly down-regulated the mRNA expression levels of Nuclear Factor-kappa B (NF-κB), a nuclear transcriptional activator as well as the mRNA expression of the cytoplasmic SOD1 gene which encodes Cu/Zn SOD, the first line defense against superoxide radicals.ConclusionCollectively, ASCex could act as a potent chemotherapeutic drug against colon cancer, likely through the influence of its rich active metabolites which interfere with various biological pathways including inhibition of protein synthesis during cellular growth and marked induction of antioxidative capacity in the colonic mucosa. This role has been extensively discussed herein.

Dataset Information

Stress levels over time in the introduced ascidian Styela plicata: the effects of temperature and salinity variations on hsp70 gene expression.

Publications

Stress levels over time in the introduced ascidian Styela plicata: the effects of temperature and salinity variations on hsp70 gene expression.

Similar Datasets

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