No abstract

Disseminated neoplasia (DN) is one of the most challenging and unrecognised diseases occurring in aquatic fauna. It has been diagnosed in four bivalve species from the Gulf of Gdańsk (Southern Baltic Sea) with the highest frequency in Macoma balthica (formerly Limecola balthica), reaching up to 94% in some populations. The aetiology of DN in the Baltic Sea has not yet been identified, with earlier studies trying to link its occurrence with environmental pollution. Taking into account recent research providing evidence that DN is horizontally transmitted as clonal cells between individuals in some bivalve species, we aimed to test whether DN is a bivalve transmissible neoplasia (BTN) in the population of M. balthica from the Gulf of Gdańsk highly affected with cancer. We examined mitochondrial cytochrome c oxidase I (mtCOI) and elongation factor 1α (EF1α) sequences of genomes obtained from haemolymph and tissues of neoplastic and healthy individuals. Sequence analysis resulted in detection of an independent transmissible cancer lineage occurring in four neoplastic clams that is not present in healthy animals. This study describes the first case of BTN in the clam M. balthica (MbaBTN), providing further insights for studies on this disease.

Disseminated neoplasia (DN) is one of the most challenging and unrecognised diseases occurring in aquatic fauna. It has been diagnosed in four bivalve species from the Gulf of Gdańsk (Southern Baltic Sea) with the highest frequency in Limecola balthica (formerly Macoma balthica), reaching up to 94% in some populations. The aetiology of DN in the Baltic Sea has not yet been identified, with earlier studies trying to link its occurrence with environmental pollution. Taking into account recent research providing evidence that DN is horizontally transmitted as clonal cells between individuals in some bivalve species, we aimed to test whether DN is a transmissible cancer in the population of L. balthica from the Gulf of Gdańsk highly affected with cancer. We examined mitochondrial cytochrome c oxidase I (mtCOI) and elongation factor 1α (EF1α) sequences of genomes obtained from haemolymph and tissues of neoplastic and healthy individuals. Sequence analysis resulted in detection of an independent transmissible cancer lineage occurring in 4 neoplastic clams that is not present in healthy animals. This paper describes the first case of transmissible DN in the clam L. balthica providing further insights for studies on this disease.

The Puck Bay is an area characterised by specific hydrodynamic conditions that determine the distribution and composition of phytoplankton. The aim of this study was to investigate the differences in the phytoplankton composition and the content of photosynthetic pigments between the Puck Bay and open Baltic Sea. The material was collected from four stands which were localised in the inner and outer part of Hel Peninsula. In this study, it has been demonstrated that the composition of individual species of phytoplankton differed between stands in the inner and outer part of the Puck Bay. This investigation has also shown that the number of phytoplankton taxa was similar in three stands and it was much lower on the last stand (Stand 4). The differences in the concentration of photosynthetic pigments between all stands have also been observed.

No abstract

Background/Aims: Occurring in marine invertebrates infectious haemic neoplasia (bivalves transmissible neoplasia, BTN) arises from genome instabilities leading to multilevel malfunctions and unregulated cell division of presumably haemocyte precursors. As its biochemical characterisation remains unknown, we here present the first data describing selected aspects of the physiology and biochemistry of the disease a in model clam Macoma balthica. We chose free amino acids (FAA) composition, mitochondrial respiration and enzymatic activity, oxidative stress enzymes activities and corticosteroids profile as markers of this contagious cancer. Methods: Selected markers were measured in neoplastic and healthy clams and two tissue types, haemolymph and solid tissue. FAA composition was assessed in the haemolymph samples using high performance liquid chromatography-mass spectrometry (LC/MS). Mitochondrial respiration analysis was performed on haemocytes using oxygen electrodes integrated system Seahorse XFp. Mitochondrial enzymes activities were measured using spectrophotometry (cytochrome oxidase, COX) and commercial kit (succinate dehydrogenase, SDH). Total Antioxidant Capacity (TAC), Acetylocholinesterase (AChE), Protein Carbonyl Content (CBO) and Malondialdehyde (MDA) levels were measured in the solid tissue using analytical kits, and glutathione (GSH) was measured spectrophotometrically. Corticosteroids profile, measured in the solid tissue, was obtained with Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (HPLC–ESI-MS/MS) technique. Results: In both clam groups nine FAAs were detected with Asp, Glu, Pro, Ser constituting over 90% of total FAA content. Significantly higher Gln level was detected in BTN positive clams. In neoplastic clams, an impairment of mitochondrial metabolism was observed as a decrease in mitochondrial oxygen consumption and lower cytochrome c oxidase activity. In the neoplastic clams significantly higher concentration of low molecular weight antioxidants was found. Finally, we report high level of corticosterone and lower levels of dehydrocorticosterone, cortisol and cortisone in healthy clams and elevated cortisol level in BTN individuals. Conclusion: Neoplastic clams are characterized by altered mitochondrial metabolism, with a potential key role of glutamine (Gln) in cancer cells energy production. Despite low aerobic respiration, BTN cells have efficient antioxidative response to elevated concentration of ROS. Elevated cortisol level in BTN-positive clams may indicate an important role of this corticosteroid in cancer biochemistry. Thus, we here provide the first results of selected physiological and biochemical aspects of BTN, making an important step in studying cancer epidemiology in wildlife.

Occurring in marine invertebrates haemic (leukemia-like) neoplasia, a disease of potentially infectious nature, arises from genome instabilities leading to multilevel malfunctions and unregulated cell division of presumably haemocyte precursors. As its biochemical characterisation remains unknown, we here present results describing selected physiological and biochemical aspects of the disease measured in neoplastic and healthy clams Limecola balthica. Activities of adenosine deaminase (ADA), alkaline phosphatase (ALP) and FAA levels were measured in haemolymph but no differences in ADA and ALP activities between healthy and neoplastic clams were found. In both clam groups nine FAAs were detected with Asp, Glu, Pro, Ser constituting over 90% of total FAA content. Significantly higher Gln level was detected in leukemic-like clams suggesting an essential role of this FAA in cancer energy production. In neoplastic cells, an impairment of mitochondrial metabolism was observed as a decrease in mitochondrial oxygen consumption and lower cytochrome c oxidase activity. Neoplastic clams were also characterised by significantly higher concentration of ROS, but no elevated response of the oxidative stress markers were found suggesting an efficient antioxidant response. Finally, we, for the first time, report high levels of corticosterone and lower amounts of dehydrocorticosterone, cortisol and cortisone in healthy clams with elevated cortisol level found in neoplastic individuals.

Potentially harmful compounds including pharmaceuticals are commonly found in marine waters and sediments. Amongst those, antibiotics and their metabolites are detected worldwide in various abiotic (at concentrations as high as µg/L) and biotic matrices at ng/gram of tissue, posing a risk to non-target species exposed to them such as blue mussels. Amongst those, oxytetracycline (OTC) belongs to the most detected antibiotics in the marine environment. In this work, we concentrated on studying the potential induction of oxidative stress, activation of cellular detoxification processes (including Phase I and Phase II xenobiotic biotransformation enzymes) and multixenobiotic resistance pumps (Phase III) as well as changes in the aromatisation efficiency in Mytilus trossulus exposed to 100 μg/L OTC. Our results show that 100 µg/L OTC concentration did not provoke cellular oxidative stress and did not affect the expression of genes involved in detoxification processes in our model. Moreover, no effect of OTC on aromatisation efficiency was found. Instead, phenoloxidase activity measured in haemolymph was significantly higher in OTC exposed mussels than in those from the control (30.95 ± 3.33 U/L and 17.95 ± 2.75 U/L, respectively). OTC exposed mussels were also characterised by a tissue-dependant activation of major vault protein (MVP) gene expression (1.5 times higher in gills and 2.4 times higher in the digestive system) and a decreased expression of the nuclear factor kappa B-a (NF-κB) gene (3.4 times lower in the digestive system) when compared to those from the control. Additionally, an elevated number of regressive changes and inflammatory responses in tissues such as gills, digestive system and mantle (gonads) was observed underlining the worsening of bivalves’ general health. Therefore, instead of a free-radical effect of OTC, we for the first time describe the occurrence of typical changes resulting from antibiotic therapy in non-target organisms like M. trossulus exposed to antibiotics such as OTC.