DNA damage in two bivalve species: Mytilus galloprovincialis and Ruditapes decussatus from the South coast of Portugal

Dissertação de mest., Estudos Marinhos e Costeiros, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2009

Polycyclic aromatic hydrocarbons and oxidative stress markers in the clam Ruditapes decussatus from the Ria Formosa (Portugal)

Tese dout., Ciências e Tecnologias do Ambiente, Universidade do Algarve, 2007

Estudo do efeito de contaminantes na espécie sentinela, a amêijoa Ruditapes decussatus, por intermédio da análise da expressão proteica: aplicação à monitorização do meio marinho

Tese dout., Ciências e Tecnologias do Ambiente, 2009, Universidade do Algarve

Seasonal variations in gross biochemical composition, percent edibility, and condition index of the clam Ruditapes Decussatus cultivated in the Ria Formosa (South Portugal)

The grooved carpet shell clam, Ruditapes decussatus (L. 1758), is one of the most popular and profitable molluscs exploited in rearing plots in the Mediterranean. However, annual catch has been declining steadily since the early nineties. In order to understand the seasonality of its nutritional value, thus providing an improved basis for economical valuation of the resource, gross biochemical composition, percentage edibility and condition index were investigated during a year with monthly periodicity in a commercially exploited population of the clam Ruditapes decussatus in the Ria Formosa, a temperate mesotidal coastal lagoon located in the south of Portugal. Our results show that total and non-protein nitrogen co-varied during the year, resulting in a protein content that peaked in the warmest months. Although complementary in summer, carbohydrate and lipid contents showed irregular annual trends. The observed seasonality was comparable to that shown by studies elsewhere at similar latitudes, and are underpinned by the reproductive cycle of the species. Our results show the clams to be at their prime nutritional value at the beginning of summer, when protein content peaks.

A juvenile recruitment prediction model for Ruditapes decussatus (L.) (Bivalvia : Mollusca)

Despite the importance of larval abundance in determining the recruitment of benthic marine invertebrates and as a major factor in marine benthic community structure, relating planktonic larval abundance with post-settlement post-larvae and juveniles in the benthos is difficult. It is hampered by several methodological difficulties, including sampling frequency, ability to follow larval and post-larval or juvenile cohorts, and ability to calculate growth and mortality rates. In our work, an intensive sampling strategy was used. Larvae in the plankton were collected at weekly intervals, while post-larvae that settled into collectors were analysed fortnightly. Planktonic larval and benthic post-larval/juvenile cohorts were determined, and growth and mortality rates calculated. Integration of all equations allowed the development of a theoretical formulation that, based on the abundance and planktonic larval duration, permits an estimation of the future abundance of post-larvae/juveniles during the first year of benthic life. The model can be applied to a sample in which it was necessary only to measure larval length.

Effects of environmental conditions on planktonic abundances, benthic recruitment and growth rates of the bivalve mollusc Ruditapes decussatus in a Portuguese coastal lagoon

Controlling environmental parameters for the early stages of marine invertebrates have received little attention, particularly in field studies. This study involves measurement of abundances and growth rates of the bivalve Ruditapes decussatus Linnaeus 1758 during its planktonic larval and early benthic life stages in a coastal lagoon: Ria Formosa, Portugal. Measured abundances were compared with tidal amplitude, water temperature, salinity, wind velocity and direction, and a food availability indicator 2chlorophyll a). Data were obtained on abundance and prodissoconch length of the larvae, measured two tothreetimes perweek,and ofpost-larval stagesindividuals thathadsettled inartificial collectors over10months.Larval and juvenile cohorts were identified using size-frequency distributions and larval ages estimated by larval shell growth lines.

Variações sazonais da composição química e índice de condição da amêijoa-boa, Ruditapes decussatus, na Ria Formosa

A nível nacional, por reunir as condições mais propícias para a reprodução e desenvolvimento da amêjoa-boa (Ruditapes decussatus), a Ria Formosa constitui o mais importante centro de exploração desta espécie de elevado valor comercial, representando cerca de 80% das amêijoas comercializadas em Portugal. O cultivo é realizado em viveiros, explorados por mariscadores, organizados em associações. Uma estimativa conservadora indica que existem mais de mil viveiros na Ria Formosa, os quais providenciam ocupação para cerca de dez mil pessoas. Com este trabalho pretendeu-se determinar a variação mensal dos teores em proteínas, hidratos de carbono, lípidos, humidade e cinzas, na amêijoa-boa. Paralelamente, calculou-se um índice de condição fisiológica baseado nos pesos do miolo e da concha. Estes parâmetros foram depois relacionados de forma a avaliar a sazonalidade da composição nutricional da amêijoa-boa e a sua eventual repercussão na comercialização e gestão dos viveiros deste bivalve na Ria Formosa.

Estudo da deterioração da amêijoa-boa Ruditapes decussatus (Linnaeus, 1758)

Dissertação de mest., Tecnologia de Alimentos, Instituto Superior de Engenharia, Univ. do Algarve, 2013

Effects of mixture of nanoparticles under different salinity in the clams Ruditapes philippinarum and Ruditapes decussatus

Dissertação de mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidadde do Algarve, 2015

Seawater carbonate chemistry and Ruditapes decussatus biological processes during experiments, 2011

We investigated the effects of ocean acidification on juvenile clams Ruditapes decussatus (average shell length 10.24 mm) in a controlled CO2 perturbation experiment. The carbonate chemistry of seawater was manipulated by diffusing pure CO2, to attain two reduced pH levels (by -0.4 and -0.7 pH units), which were compared to unmanipulated seawater. After 75 days we found no differences among pH treatments in terms of net calcification, size or weight of the clams. The naturally elevated total alkalinity of local seawater probably contributed to buffer the effects of increased pCO2 and reduced pH. Marine organisms may, therefore, show diverse responses to ocean acidification at local scales, particularly in coastal, estuarine and transitional waters, where the physical-chemical characteristics of seawater are most variable. Mortality was significantly reduced in the acidified treatments. This trend was probably related to the occurrence of spontaneous spawning events in the control and intermediate acidification treatments. Spawning, which was unexpected due to the small size of the clams, was not observed for the pH -0.7 treatment, suggesting that the increased survival under acidified conditions may have been associated with a delay in the reproductive cycle of the clams. Future research about the impacts of ocean acidification on marine biodiversity should be extended to other types of biological and ecological processes, apart from biological calcification.

mRNA-Seq and microarray development for the Grooved carpet shell clam, Ruditapes decussatus: a functional approach to unravel host -parasite interaction

Background The Grooved Carpet shell clam Ruditapes decussatus is the autochthonous European clam and the most appreciated from a gastronomic and economic point of view. The production is in decline due to several factors such as Perkinsiosis and habitat invasion and competition by the introduced exotic species, the manila clam Ruditapes philippinarum. After we sequenced R. decussatus transcriptome we have designed an oligo microarray capable of contributing to provide some clues on molecular response of the clam to Perkinsiosis. Results A database consisting of 41,119 unique transcripts was constructed, of which 12,479 (30.3%) were annotated by similarity. An oligo-DNA microarray platform was then designed and applied to profile gene expression in R. decussatus heavily infected by Perkinsus olseni. Functional annotation of differentially expressed genes between those two conditionswas performed by gene set enrichment analysis. As expected, microarrays unveil genes related with stress/infectious agents such as hydrolases, proteases and others. The extensive role of innate immune system was also analyzed and effect of parasitosis upon expression of important molecules such as lectins reviewed. Conclusions This study represents a first attempt to characterize Ruditapes decussatus transcriptome, an important marine resource for the European aquaculture. The trancriptome sequencing and consequent annotation will increase the available tools and resources for this specie, introducing the possibility of high throughput experiments such as microarrays analysis. In this specific case microarray approach was used to unveil some important aspects of host-parasite interaction between the Carpet shell clam and Perkinsus, two non-model species, highlighting some genes associated with this interaction. Ample information was obtained to identify biological processes significantly enriched among differentially expressed genes in Perkinsus infected versus non-infected gills. An overview on the genes related with the immune system on R. decussatus transcriptome is also reported.