M. Carballal - Academia.edu (original) (raw)

Papers by M. Carballal

Research paper thumbnail of First detection of the protozoan parasite Bonamia exitiosa (Haplosporidia) infecting flat oyster Ostrea edulis grown in European waters

Aquaculture, 2008

The haplosporidian Bonamia exitiosa was found infecting the European flat oyster Ostrea edulis in... more The haplosporidian Bonamia exitiosa was found infecting the European flat oyster Ostrea edulis in the Galician coast (NW Spain), which represents the first report of this parasite along European waters. Histopathology and molecular characterization of the small subunit ribosomal DNA gene were performed to identify this species. Examination of histological sections showed two microcell types, the smaller one corresponding to Bonamia ostreae and the larger one to B. exitiosa. Phylogenetic analysis places the sequence herein reported in a clade with Bonamia species of the Southern hemisphere, namely B. exitiosa, B. roughleyi and Bonamia sp. from North Carolina and Chile. Subsequent PCR-RFLPs analysis showed a highly-endemiotopic infection by B. exitiosa, demonstrating the success of this haplosporidian to infect the European flat oyster in the Galician marine ecosystem even in concurrent infections with B. ostreae.

Research paper thumbnail of Oyster parasites Bonamia ostreae and Bonamia exitiosa co-occur in Galicia (NW Spain): spatial distribution and infection dynamics

Diseases of Aquatic Organisms, 2013

Bonamiosis constrains the flat oyster industry worldwide. The protistan species Bonamia ostreae h... more Bonamiosis constrains the flat oyster industry worldwide. The protistan species Bonamia ostreae had been considered solely responsible for this disease in Europe, but the report of B. exitiosa infecting Ostrea edulis 5 yr ago in Galicia (NW Spain), and subsequently in other European countries, raised the question of the relevance of each species in bonamiosis. The spatial distribution of B. exitiosa and B. ostreae in Galicia was addressed by sampling 7 natural O. edulis beds and 3 culture raft areas, up to 3 times in the period 2009 to 2010. B. ostreae infected flat oysters in every natural bed and every raft culture area. True B. exitiosa infections (histological diagnosis) were detected in every raft culture area but only in 2 natural beds, i.e. in 4 rías. PCR-positive results for B. exitiosa were recorded in 4 out of 5 beds where true infections were not found, thus the occurrence of B. exitiosa in those 4 beds cannot be ruled out. Additionally, 4 cohorts of hatchery-produced oyster spat were transferred to a raft to analyse Bonamia spp. infection dynamics through oyster on-growing. The highest percentages of oysters PCR-positive for both Bonamia spp. were recorded in the first months of on-growing; other peaks of PCR-positive diagnosis were successively lower. Differences in the percentage of PCR-positive cases and in the prevalence of true infection between B. exitiosa and B. ostreae through on-growing were not significant. Our results support that B. exitiosa is adapted to infect O. edulis in the Galician marine ecosystem.

Research paper thumbnail of Cockle Cerastoderma edule fishery collapse in the Ría de Arousa (Galicia, NW Spain) associated with the protistan parasite Marteilia cochillia

Diseases of Aquatic Organisms, 2014

The highest shellfishery catch in Galicia (NW Spain) has traditionally been cockle Cerastoderma e... more The highest shellfishery catch in Galicia (NW Spain) has traditionally been cockle Cerastoderma edule. The shellfish bed located in Lombos do Ulla (Ría de Arousa) used to be among those with the highest cockle production; however, cockle mortality rate increased sharply in this bed in April 2012, reaching 100% in May 2012. Salinity and temperature were discounted as potential causes of the mortality. Marteiliosis, which was first detected in February 2012 and reached 100% prevalence in April 2012, was identified as the most probable cause. Marteiliosis had never been detected in Galician cockles, but extensive surveillance of the Galician coast in May to July 2012 detected marteiliosis in most cockle beds of the Ría de Arousa, whereas it was not found in other rías; 2 mo later, the cockle catch in the Ría de Arousa became negligible. Examination of the aetiological agent of marteiliosis with light and transmission electron microscopy supported its assignation to the genus Marteilia; morphological features showed similarity, but not complete identity, with the recently described species M. cochillia Carrasco et al., 2013. Regarding its molecular characterisation, a consensus sequence of 4433 bp containing a partial sequence of the intergenic spacer region, the complete 18S rRNA gene and a partial sequence of the first internal transcribed spacer region was obtained. The obtained sequences were compared with those available for Marteilia spp. and other Paramyxida. Molecular data support that this parasite corresponds to the species M. cochillia, and a PCR assay was designed for its specific diagnosis. The association of huge cockle mortality with M. cochillia infection urges extreme caution to avoid spreading this disease.

Research paper thumbnail of Morphological Characterization of the Hemocytes of the Clam,Ruditapes decussatus(Mollusca: Bivalvia)

Journal of Invertebrate Pathology, 1997

Hemocytes play an important role in internal defence in molluscs. The morphology of hemolymph cel... more Hemocytes play an important role in internal defence in molluscs. The morphology of hemolymph cells was studied for the first time in Ruditapes decussatus. Two main types of hemocytes (hyalinocytes and granulocytes) exist in R. decussatus. Three types of granulocytes were identified by light microscopy, in accordance with the presence of basophilic or acidophilic granules or a mixture of both in the cytoplasm. The existence of hyalinocytes and granulocytes was confirmed by electron microscopy. Some monoclonal antibodies (MABs) raised against hemocytes of Crassostrea gigas showed cross-reactivity with the total population of hemocytes of R. decussatus; however, none of the MABs raised against hemocytes of Mytilus edulis showed cross-reactivity. The MABs assayed did not allow us to distinguish hemocyte subpopulations. r 1997 Academic Press

Research paper thumbnail of Virus-like particles associated with large foci of heavy hemocytic infiltration in cockles Cerastoderma edule from Galicia (NW Spain)

Journal of Invertebrate Pathology, 2003

Research paper thumbnail of Disseminated neoplasia causes changes in ploidy and apoptosis frequency in cockles Cerastoderma edule

Journal of Invertebrate Pathology, 2013

A proliferative disease, usually referred as disseminated neoplasia (DN), shows high prevalence i... more A proliferative disease, usually referred as disseminated neoplasia (DN), shows high prevalence in some cockle Cerastoderma edule beds of Galicia (NW Spain). Chromosome counts, examination of chromosome morphology, DNA quantification by flow cytometry and estimation of apoptosis frequency by TUNEL assay and flow cytometry were performed in cockles with different DN severity. Metaphases obtained from gills of DN-affected cockles displayed a chromosome number ranging from 41 to 145, while normal number is 38; changes in chromosome morphology were also evident, with numerous microchromosomes occurring. Haemolymph flow cytometry analysis revealed difference in DNA content between healthy and DN-affected cockles. Aneuploid peaks ranged from 1.3n to 8.9n. Apoptosis frequency was determined on histological sections (TUNEL assay) and haemolymph samples (flow cytometry). Both techniques revealed neoplastic cells in apoptosis. The higher DN severity, the lower the percentage of apoptotic cells. According to flow cytometry results, the negative association between DN severity and apoptosis frequency only affected the neoplastic cells, whereas DN did not significantly affect the percentage of apoptotic hyalinocytes or apoptotic granulocytes.

Research paper thumbnail of Parasites and Pathologic Conditions of the Cockle Cerastoderma edule Populations of the Coast of Galicia (NW Spain)

Journal of Invertebrate Pathology, 2001

A survey of pathological conditions affecting cockle populations of the most economically importa... more A survey of pathological conditions affecting cockle populations of the most economically important natural beds of Galician estuaries in NW Spain was performed. Samples of 30 adult cockles were collected from each of 34 natural beds in the spring of 1999 and processed by histological techniques. Disseminated neoplasia were seen in samples from most of the natural beds, in some cases with a high prevalence. The gregarine Nematopsis sp., larval trematode stages, and branchial extracellular large cysts enclosing bacterialike microorganisms were the most prevalent parasites. Paravortex cardii, intracellular colonies of rickettsiae-like organisms in digestive and gill epithelium, Pseudoklossia sp. coccidians, Trichodina sp., and other ciliates were frequently seen in the samples. Copepods in gills and intestine and unidentified gregarines in intestine epithelia and surrounding connective tissue were less prevalent and were observed in samples of some natural beds. Large foci of heavy hemocytic infiltration were detected in a few sites only. Cysts of Steinhausia sp. and plasmodia and spores of a haplosporidian were seen in cockles from two localities. Inflammation was frequently observed in the samples. Some of the parasites and pathological conditions could be associated with mortality.

Research paper thumbnail of Enzyme characterisation of the circulating haemocytes of the carpet shell clam,Ruditapes decussatus(Mollusca:bivalvia)

Fish & Shellfish Immunology, 1997

The occurrence of a number of lysosomal enzymes (Proteases, glycosidases, phosphatases, and ester... more The occurrence of a number of lysosomal enzymes (Proteases, glycosidases, phosphatases, and esterases) in Ruditapes decussatus haemocytes was demonstrated by cytochemical and colorimetric techniques. The levels of 18 enzymes tested monthly varied through the study period (18 months), although they did not conform to a seasonal pattern of variation. No important e#ect of clam age on enzyme activity levels of haemocytes was detected. In those cytochemical assays in which distinction between granulocytes and hyalinocytes was possible, lysosomal enzymes were only found in granulocytes. Phosphatase was detected inside cytoplasmic granules of granulocytes, suggesting the granules to be lysosomes. NADPH oxidase was not detected in clam haemocytes, which is consistent with the absence of oxidative metabolism coupled with phagocytosis in haemocytes of this clam species. Levels of lysozyme detected inside haemocytes were higher than in serum.

Research paper thumbnail of Expression of mutant protein p53 and Hsp70 and Hsp90 chaperones in cockles Cerastoderma edule affected by neoplasia

Diseases of Aquatic Organisms, 2010

High prevalence of disseminated neoplasia has been found in cockles Cerastoderma edule of Galicia... more High prevalence of disseminated neoplasia has been found in cockles Cerastoderma edule of Galicia (NW Spain). Disseminated neoplasia has been associated with high mortalities of various bivalve species. In vertebrates, proteins such as p53 and heat shock proteins (HSPs) play important roles in carcinogenesis. The protein p53 has been detected in neoplastic cells of bivalve molluscs such as Mytilus edulis, Mytilus trossulus, Mya arenaria, Spisula solidissima, Crassostrea rhizophorae and Crassostrea gigas. In this study, western blotting analyses were used to test the expression of Hsp70, Hsp90 and mutant p53 proteins in the cells and plasma of the haemolymph of cockles showing various intensities of neoplasia. Disseminated neoplasia was previously diagnosed by examination of stained haemolymph monolayers with light microscopy. In the present study, mutant p53 was detected in haemolymph cells of cockles diagnosed as affected by moderate and heavy neoplasia intensity, whereas it was not detected in cockles with either no or light neoplasia. The higher the neoplasia intensity, the higher the levels of Hsp70 and Hsp90. These proteins were not found in plasma. The results reveal the possible association between p53 and HSPs in neoplastic cells of cockles, which could prevent p53 from carrying out its functions, as occurs in human cancers.

Research paper thumbnail of Disseminated neoplasia and large foci indicating heavy haemocytic infiltration in cockles Cerastoderma edule from Galicia (NW Spain)

Diseases of Aquatic Organisms, 2001

Research paper thumbnail of Study of perkinsosis in the carpet shell clam Tapes decussatus in Galicia (NW Spain). II. Temporal pattern of disease dynamics and association with clam mortality

Diseases of Aquatic Organisms, 2005

Temporal dynamics of the infection by Perkinsus olseni in a clam (Tapes decussatus) bed was studi... more Temporal dynamics of the infection by Perkinsus olseni in a clam (Tapes decussatus) bed was studied over 5 yr (March 1996 to December 2000. Diagnostic techniques were compared to assess their suitability for epizootiological purposes. A technique based on incubation of 2 gill lamellae in Ray's fluid thioglycollate medium (RFTM) was more sensitive, quicker and cheaper than examination of histological sections. Incubation of the whole-clam soft tissues in RFTM allowed detection of very light infections that were not detected with incubation of only 2 gill lamellae. Nevertheless, the correlation between the infection intensity estimated by both RFTM incubations was high. Infection intensity was significantly and positively correlated with clam size/age. No infected clam smaller than 20 mm was found. There was an annual pattern of infection involving lower mean infection intensity and prevalence in winter and higher values for both variables from spring to autumn, with 2 main annual peaks in spring and late summer-early autumn. This temporal pattern was significantly associated with the seawater temperature. The annual spring peak of infection intensity occurred when seawater temperature was around 15°C. Monthly mortality in the clam bed peaked in spring and summer -after peaks of P. olseni infection intensity and concurrently with high seawater temperature. A comparison of percentage mortality between clams from 2 sources (a perkinsosis-affected and a non-affected area) placed in the same clam bed revealed significantly higher mortality in the clams originating from the perkinsosis-affected area.

Research paper thumbnail of Biomarkers and transcription level of cancer-related genes in cockles Cerastoderma edule from Galicia (NW Spain) with disseminated neoplasia

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2010

as well as several known biomarkers, such as vitellogenin, the zona pellucida proteins and metall... more as well as several known biomarkers, such as vitellogenin, the zona pellucida proteins and metallothionein. Here we present data from a monitoring study performed on eelpout captured along the Swedish coast. We have combined traditional monitoring measurements with large scale gene expression analysis. As the eelpout lives relatively stationary we can link the microarray data and observed physiological responses to the environmental situation where the fish was caught. Furthermore, the viviparity of the eelpout gives the unique opportunity to associate the effects of pollutants to individual reproductive performance, including the development of embryos and fry.

Research paper thumbnail of Incidence of bonamiasis in flat oyster, Ostrea edulis L., cultured in Galicia (N.W. Spain)

Aquaculture, 1992

Montn. J., Carballal, M.J., Lopez, M.C. and Mourelle, S.G., 1992. Incidence of bonamiash in flat ... more Montn. J., Carballal, M.J., Lopez, M.C. and Mourelle, S.G., 1992. Incidence of bonamiash in flat 0yw.r. Oslrea eduhr L.. cultured in Gslicia (NW. Spain ). Aqwaculture, 107: 189-I 95.

Research paper thumbnail of Evidence of retroviral etiology for disseminated neoplasia in cockles (Cerastoderma edule)

Journal of invertebrate …, 2007

Epizootiologic outbreaks of disseminated neoplasia have been reported in association with massive... more Epizootiologic outbreaks of disseminated neoplasia have been reported in association with massive mortalities of various bivalve species. In cockles, Cerastoderma edule, this pathological condition was described in Ireland and France. Since 1997, diVerent populations aVected by this pathology have been detected in Galicia (NW Spain). Transmission electron microscopy allowed the visualization of virus-like particles in neoplastic cells, resembling a retrovirus-like agent. To conWrm this hypothesis, we used a commercial kit for detection and quantiWcation of reverse transcriptase (RT) activity, based on the use of bromo-deoxyuridine triphosphate (BrdUTP) and a BrdU binding antibody conjugated to alkaline phosphatase. In addition, we developed a product-enhanced RT assay using RNA of hepatitis A virus as a template. These two assays showed positive RT activity in 90.9 and 81.8% of samples, respectively, from cockles displaying disseminated neoplasia as determined by light microscopy. These results strongly support the hypothesis of retroviral etiology for this pathological condition.

Research paper thumbnail of First detection of the protozoan parasite Bonamia exitiosa (Haplosporidia) infecting flat oyster Ostrea edulis grown in European waters

Aquaculture, 2008

The haplosporidian Bonamia exitiosa was found infecting the European flat oyster Ostrea edulis in... more The haplosporidian Bonamia exitiosa was found infecting the European flat oyster Ostrea edulis in the Galician coast (NW Spain), which represents the first report of this parasite along European waters. Histopathology and molecular characterization of the small subunit ribosomal DNA gene were performed to identify this species. Examination of histological sections showed two microcell types, the smaller one corresponding to Bonamia ostreae and the larger one to B. exitiosa. Phylogenetic analysis places the sequence herein reported in a clade with Bonamia species of the Southern hemisphere, namely B. exitiosa, B. roughleyi and Bonamia sp. from North Carolina and Chile. Subsequent PCR-RFLPs analysis showed a highly-endemiotopic infection by B. exitiosa, demonstrating the success of this haplosporidian to infect the European flat oyster in the Galician marine ecosystem even in concurrent infections with B. ostreae.

Research paper thumbnail of First detection of the protozoan parasite Bonamia exitiosa (Haplosporidia) infecting flat oyster Ostrea edulis grown in European waters

Aquaculture, 2008

The haplosporidian Bonamia exitiosa was found infecting the European flat oyster Ostrea edulis in... more The haplosporidian Bonamia exitiosa was found infecting the European flat oyster Ostrea edulis in the Galician coast (NW Spain), which represents the first report of this parasite along European waters. Histopathology and molecular characterization of the small subunit ribosomal DNA gene were performed to identify this species. Examination of histological sections showed two microcell types, the smaller one corresponding to Bonamia ostreae and the larger one to B. exitiosa. Phylogenetic analysis places the sequence herein reported in a clade with Bonamia species of the Southern hemisphere, namely B. exitiosa, B. roughleyi and Bonamia sp. from North Carolina and Chile. Subsequent PCR-RFLPs analysis showed a highly-endemiotopic infection by B. exitiosa, demonstrating the success of this haplosporidian to infect the European flat oyster in the Galician marine ecosystem even in concurrent infections with B. ostreae.

Research paper thumbnail of Oyster parasites Bonamia ostreae and Bonamia exitiosa co-occur in Galicia (NW Spain): spatial distribution and infection dynamics

Diseases of Aquatic Organisms, 2013

Bonamiosis constrains the flat oyster industry worldwide. The protistan species Bonamia ostreae h... more Bonamiosis constrains the flat oyster industry worldwide. The protistan species Bonamia ostreae had been considered solely responsible for this disease in Europe, but the report of B. exitiosa infecting Ostrea edulis 5 yr ago in Galicia (NW Spain), and subsequently in other European countries, raised the question of the relevance of each species in bonamiosis. The spatial distribution of B. exitiosa and B. ostreae in Galicia was addressed by sampling 7 natural O. edulis beds and 3 culture raft areas, up to 3 times in the period 2009 to 2010. B. ostreae infected flat oysters in every natural bed and every raft culture area. True B. exitiosa infections (histological diagnosis) were detected in every raft culture area but only in 2 natural beds, i.e. in 4 rías. PCR-positive results for B. exitiosa were recorded in 4 out of 5 beds where true infections were not found, thus the occurrence of B. exitiosa in those 4 beds cannot be ruled out. Additionally, 4 cohorts of hatchery-produced oyster spat were transferred to a raft to analyse Bonamia spp. infection dynamics through oyster on-growing. The highest percentages of oysters PCR-positive for both Bonamia spp. were recorded in the first months of on-growing; other peaks of PCR-positive diagnosis were successively lower. Differences in the percentage of PCR-positive cases and in the prevalence of true infection between B. exitiosa and B. ostreae through on-growing were not significant. Our results support that B. exitiosa is adapted to infect O. edulis in the Galician marine ecosystem.

Research paper thumbnail of Cockle Cerastoderma edule fishery collapse in the Ría de Arousa (Galicia, NW Spain) associated with the protistan parasite Marteilia cochillia

Diseases of Aquatic Organisms, 2014

The highest shellfishery catch in Galicia (NW Spain) has traditionally been cockle Cerastoderma e... more The highest shellfishery catch in Galicia (NW Spain) has traditionally been cockle Cerastoderma edule. The shellfish bed located in Lombos do Ulla (Ría de Arousa) used to be among those with the highest cockle production; however, cockle mortality rate increased sharply in this bed in April 2012, reaching 100% in May 2012. Salinity and temperature were discounted as potential causes of the mortality. Marteiliosis, which was first detected in February 2012 and reached 100% prevalence in April 2012, was identified as the most probable cause. Marteiliosis had never been detected in Galician cockles, but extensive surveillance of the Galician coast in May to July 2012 detected marteiliosis in most cockle beds of the Ría de Arousa, whereas it was not found in other rías; 2 mo later, the cockle catch in the Ría de Arousa became negligible. Examination of the aetiological agent of marteiliosis with light and transmission electron microscopy supported its assignation to the genus Marteilia; morphological features showed similarity, but not complete identity, with the recently described species M. cochillia Carrasco et al., 2013. Regarding its molecular characterisation, a consensus sequence of 4433 bp containing a partial sequence of the intergenic spacer region, the complete 18S rRNA gene and a partial sequence of the first internal transcribed spacer region was obtained. The obtained sequences were compared with those available for Marteilia spp. and other Paramyxida. Molecular data support that this parasite corresponds to the species M. cochillia, and a PCR assay was designed for its specific diagnosis. The association of huge cockle mortality with M. cochillia infection urges extreme caution to avoid spreading this disease.

Research paper thumbnail of Morphological Characterization of the Hemocytes of the Clam,Ruditapes decussatus(Mollusca: Bivalvia)

Journal of Invertebrate Pathology, 1997

Hemocytes play an important role in internal defence in molluscs. The morphology of hemolymph cel... more Hemocytes play an important role in internal defence in molluscs. The morphology of hemolymph cells was studied for the first time in Ruditapes decussatus. Two main types of hemocytes (hyalinocytes and granulocytes) exist in R. decussatus. Three types of granulocytes were identified by light microscopy, in accordance with the presence of basophilic or acidophilic granules or a mixture of both in the cytoplasm. The existence of hyalinocytes and granulocytes was confirmed by electron microscopy. Some monoclonal antibodies (MABs) raised against hemocytes of Crassostrea gigas showed cross-reactivity with the total population of hemocytes of R. decussatus; however, none of the MABs raised against hemocytes of Mytilus edulis showed cross-reactivity. The MABs assayed did not allow us to distinguish hemocyte subpopulations. r 1997 Academic Press

Research paper thumbnail of Virus-like particles associated with large foci of heavy hemocytic infiltration in cockles Cerastoderma edule from Galicia (NW Spain)

Journal of Invertebrate Pathology, 2003

Research paper thumbnail of Disseminated neoplasia causes changes in ploidy and apoptosis frequency in cockles Cerastoderma edule

Journal of Invertebrate Pathology, 2013

A proliferative disease, usually referred as disseminated neoplasia (DN), shows high prevalence i... more A proliferative disease, usually referred as disseminated neoplasia (DN), shows high prevalence in some cockle Cerastoderma edule beds of Galicia (NW Spain). Chromosome counts, examination of chromosome morphology, DNA quantification by flow cytometry and estimation of apoptosis frequency by TUNEL assay and flow cytometry were performed in cockles with different DN severity. Metaphases obtained from gills of DN-affected cockles displayed a chromosome number ranging from 41 to 145, while normal number is 38; changes in chromosome morphology were also evident, with numerous microchromosomes occurring. Haemolymph flow cytometry analysis revealed difference in DNA content between healthy and DN-affected cockles. Aneuploid peaks ranged from 1.3n to 8.9n. Apoptosis frequency was determined on histological sections (TUNEL assay) and haemolymph samples (flow cytometry). Both techniques revealed neoplastic cells in apoptosis. The higher DN severity, the lower the percentage of apoptotic cells. According to flow cytometry results, the negative association between DN severity and apoptosis frequency only affected the neoplastic cells, whereas DN did not significantly affect the percentage of apoptotic hyalinocytes or apoptotic granulocytes.

Research paper thumbnail of Parasites and Pathologic Conditions of the Cockle Cerastoderma edule Populations of the Coast of Galicia (NW Spain)

Journal of Invertebrate Pathology, 2001

A survey of pathological conditions affecting cockle populations of the most economically importa... more A survey of pathological conditions affecting cockle populations of the most economically important natural beds of Galician estuaries in NW Spain was performed. Samples of 30 adult cockles were collected from each of 34 natural beds in the spring of 1999 and processed by histological techniques. Disseminated neoplasia were seen in samples from most of the natural beds, in some cases with a high prevalence. The gregarine Nematopsis sp., larval trematode stages, and branchial extracellular large cysts enclosing bacterialike microorganisms were the most prevalent parasites. Paravortex cardii, intracellular colonies of rickettsiae-like organisms in digestive and gill epithelium, Pseudoklossia sp. coccidians, Trichodina sp., and other ciliates were frequently seen in the samples. Copepods in gills and intestine and unidentified gregarines in intestine epithelia and surrounding connective tissue were less prevalent and were observed in samples of some natural beds. Large foci of heavy hemocytic infiltration were detected in a few sites only. Cysts of Steinhausia sp. and plasmodia and spores of a haplosporidian were seen in cockles from two localities. Inflammation was frequently observed in the samples. Some of the parasites and pathological conditions could be associated with mortality.

Research paper thumbnail of Enzyme characterisation of the circulating haemocytes of the carpet shell clam,Ruditapes decussatus(Mollusca:bivalvia)

Fish & Shellfish Immunology, 1997

The occurrence of a number of lysosomal enzymes (Proteases, glycosidases, phosphatases, and ester... more The occurrence of a number of lysosomal enzymes (Proteases, glycosidases, phosphatases, and esterases) in Ruditapes decussatus haemocytes was demonstrated by cytochemical and colorimetric techniques. The levels of 18 enzymes tested monthly varied through the study period (18 months), although they did not conform to a seasonal pattern of variation. No important e#ect of clam age on enzyme activity levels of haemocytes was detected. In those cytochemical assays in which distinction between granulocytes and hyalinocytes was possible, lysosomal enzymes were only found in granulocytes. Phosphatase was detected inside cytoplasmic granules of granulocytes, suggesting the granules to be lysosomes. NADPH oxidase was not detected in clam haemocytes, which is consistent with the absence of oxidative metabolism coupled with phagocytosis in haemocytes of this clam species. Levels of lysozyme detected inside haemocytes were higher than in serum.

Research paper thumbnail of Expression of mutant protein p53 and Hsp70 and Hsp90 chaperones in cockles Cerastoderma edule affected by neoplasia

Diseases of Aquatic Organisms, 2010

High prevalence of disseminated neoplasia has been found in cockles Cerastoderma edule of Galicia... more High prevalence of disseminated neoplasia has been found in cockles Cerastoderma edule of Galicia (NW Spain). Disseminated neoplasia has been associated with high mortalities of various bivalve species. In vertebrates, proteins such as p53 and heat shock proteins (HSPs) play important roles in carcinogenesis. The protein p53 has been detected in neoplastic cells of bivalve molluscs such as Mytilus edulis, Mytilus trossulus, Mya arenaria, Spisula solidissima, Crassostrea rhizophorae and Crassostrea gigas. In this study, western blotting analyses were used to test the expression of Hsp70, Hsp90 and mutant p53 proteins in the cells and plasma of the haemolymph of cockles showing various intensities of neoplasia. Disseminated neoplasia was previously diagnosed by examination of stained haemolymph monolayers with light microscopy. In the present study, mutant p53 was detected in haemolymph cells of cockles diagnosed as affected by moderate and heavy neoplasia intensity, whereas it was not detected in cockles with either no or light neoplasia. The higher the neoplasia intensity, the higher the levels of Hsp70 and Hsp90. These proteins were not found in plasma. The results reveal the possible association between p53 and HSPs in neoplastic cells of cockles, which could prevent p53 from carrying out its functions, as occurs in human cancers.

Research paper thumbnail of Disseminated neoplasia and large foci indicating heavy haemocytic infiltration in cockles Cerastoderma edule from Galicia (NW Spain)

Diseases of Aquatic Organisms, 2001

Research paper thumbnail of Study of perkinsosis in the carpet shell clam Tapes decussatus in Galicia (NW Spain). II. Temporal pattern of disease dynamics and association with clam mortality

Diseases of Aquatic Organisms, 2005

Temporal dynamics of the infection by Perkinsus olseni in a clam (Tapes decussatus) bed was studi... more Temporal dynamics of the infection by Perkinsus olseni in a clam (Tapes decussatus) bed was studied over 5 yr (March 1996 to December 2000. Diagnostic techniques were compared to assess their suitability for epizootiological purposes. A technique based on incubation of 2 gill lamellae in Ray's fluid thioglycollate medium (RFTM) was more sensitive, quicker and cheaper than examination of histological sections. Incubation of the whole-clam soft tissues in RFTM allowed detection of very light infections that were not detected with incubation of only 2 gill lamellae. Nevertheless, the correlation between the infection intensity estimated by both RFTM incubations was high. Infection intensity was significantly and positively correlated with clam size/age. No infected clam smaller than 20 mm was found. There was an annual pattern of infection involving lower mean infection intensity and prevalence in winter and higher values for both variables from spring to autumn, with 2 main annual peaks in spring and late summer-early autumn. This temporal pattern was significantly associated with the seawater temperature. The annual spring peak of infection intensity occurred when seawater temperature was around 15°C. Monthly mortality in the clam bed peaked in spring and summer -after peaks of P. olseni infection intensity and concurrently with high seawater temperature. A comparison of percentage mortality between clams from 2 sources (a perkinsosis-affected and a non-affected area) placed in the same clam bed revealed significantly higher mortality in the clams originating from the perkinsosis-affected area.

Research paper thumbnail of Biomarkers and transcription level of cancer-related genes in cockles Cerastoderma edule from Galicia (NW Spain) with disseminated neoplasia

Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 2010

as well as several known biomarkers, such as vitellogenin, the zona pellucida proteins and metall... more as well as several known biomarkers, such as vitellogenin, the zona pellucida proteins and metallothionein. Here we present data from a monitoring study performed on eelpout captured along the Swedish coast. We have combined traditional monitoring measurements with large scale gene expression analysis. As the eelpout lives relatively stationary we can link the microarray data and observed physiological responses to the environmental situation where the fish was caught. Furthermore, the viviparity of the eelpout gives the unique opportunity to associate the effects of pollutants to individual reproductive performance, including the development of embryos and fry.

Research paper thumbnail of Incidence of bonamiasis in flat oyster, Ostrea edulis L., cultured in Galicia (N.W. Spain)

Aquaculture, 1992

Montn. J., Carballal, M.J., Lopez, M.C. and Mourelle, S.G., 1992. Incidence of bonamiash in flat ... more Montn. J., Carballal, M.J., Lopez, M.C. and Mourelle, S.G., 1992. Incidence of bonamiash in flat 0yw.r. Oslrea eduhr L.. cultured in Gslicia (NW. Spain ). Aqwaculture, 107: 189-I 95.

Research paper thumbnail of Evidence of retroviral etiology for disseminated neoplasia in cockles (Cerastoderma edule)

Journal of invertebrate …, 2007

Epizootiologic outbreaks of disseminated neoplasia have been reported in association with massive... more Epizootiologic outbreaks of disseminated neoplasia have been reported in association with massive mortalities of various bivalve species. In cockles, Cerastoderma edule, this pathological condition was described in Ireland and France. Since 1997, diVerent populations aVected by this pathology have been detected in Galicia (NW Spain). Transmission electron microscopy allowed the visualization of virus-like particles in neoplastic cells, resembling a retrovirus-like agent. To conWrm this hypothesis, we used a commercial kit for detection and quantiWcation of reverse transcriptase (RT) activity, based on the use of bromo-deoxyuridine triphosphate (BrdUTP) and a BrdU binding antibody conjugated to alkaline phosphatase. In addition, we developed a product-enhanced RT assay using RNA of hepatitis A virus as a template. These two assays showed positive RT activity in 90.9 and 81.8% of samples, respectively, from cockles displaying disseminated neoplasia as determined by light microscopy. These results strongly support the hypothesis of retroviral etiology for this pathological condition.

Research paper thumbnail of First detection of the protozoan parasite Bonamia exitiosa (Haplosporidia) infecting flat oyster Ostrea edulis grown in European waters

Aquaculture, 2008

The haplosporidian Bonamia exitiosa was found infecting the European flat oyster Ostrea edulis in... more The haplosporidian Bonamia exitiosa was found infecting the European flat oyster Ostrea edulis in the Galician coast (NW Spain), which represents the first report of this parasite along European waters. Histopathology and molecular characterization of the small subunit ribosomal DNA gene were performed to identify this species. Examination of histological sections showed two microcell types, the smaller one corresponding to Bonamia ostreae and the larger one to B. exitiosa. Phylogenetic analysis places the sequence herein reported in a clade with Bonamia species of the Southern hemisphere, namely B. exitiosa, B. roughleyi and Bonamia sp. from North Carolina and Chile. Subsequent PCR-RFLPs analysis showed a highly-endemiotopic infection by B. exitiosa, demonstrating the success of this haplosporidian to infect the European flat oyster in the Galician marine ecosystem even in concurrent infections with B. ostreae.