BackgroundIn countries with elevated prevalence of zoonotic anisakiasis and high awareness of this parasitosis, a considerable number of cases that associate Anisakis sp. (Nematoda, Anisakidae) and different bowel carcinomas have been described. Although neoplasia and embedded larvae were observed sharing the common site affected by chronic inflammation, no association between the nematode and malignancy were directly proved. Similarly, no data are available about the effect of secretory and excretory products of infecting larvae at the host’s cellular level, except in respect to allergenic interaction.MethodsTo test the mechanisms by which human non-immune cells respond to the larvae, we exposed the fibroblast cell line HS-68 to two Anisakis products (ES, excretory/secretory products; and EC, crude extract) and evaluated molecular markers related to stress response, oxidative stress, inflammation and apoptosis, such as p53, HSP70, TNF-α, c-jun and c-fos, employing cell viability assay, spectrophotometry, immunoblotting and qPCR.ResultsBoth Anisakis products led to increased production of reactive oxygen species (ROS), especially in EC-treated cells. While the ES treatment induces activation of kinases suggesting inflammation and cell proliferation (or inhibition of apoptosis), in EC-treated cells, other signaling pathways indicate the inhibition of apoptosis, marked by strong upregulation of Hsp70. Elevated induction of p53 in fibroblasts treated by both Anisakis products, suggests a significantly negative effect on the host DNA.ConclusionsThis study shows that in vitro cell response to Anisakis products can result in at least two different scenarios, which in both cases lead to inflammation and DNA damage. Although these preliminary results are far from proving a relationship between the parasite and cancer, they are the first to support the existence of conditions where such changes are feasible.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1895-5) contains supplementary material, which is available to authorized users.

The horse-bearded mussel Modiolus barbatus (Linneus, 1758) is an important edible bivalve in the Adriatic Sea; its population is especially large in the Mali Ston Bay area, where the species is present at depths up to 8 m. In order to assess the sustainable exploitation rate for this species, as well as to estimate its potential capacity for a sustainable aquaculture production, we determined the species' reproductive cycle along with its nutrient storage strategy, employing histological and biochemical methods. The population shows significantly more females than males, and no hermaphrodites. The smallest adult individual, an active male, was 16.0 mm in length, suggesting that sexual maturation starts around this length. While the period between January and February is characterized by sexual repose, early and late stages of gametogenesis were found between March and May, and spawning peaked from June till August. The increase of oocyte diameter followed the same trend. A significant positive correlation was observed between gonad index and temperature, and a negative correlation between gonad index and salinity. Oscillations of stored nutrients were tightly coupled with the gametogenic cycle.

Although alkaline phosphatase (APase) from Escherichia coli crystallizes as a symmetric dimer, it displays deviations from Michaelis-Menten kinetics, supported by a model describing a dimeric enzyme with unequal subunits [Orhanovic´S., Pavela-VrancˇicˇM. and Flogel-Mrsˇic´M. (1994) Acta. Pharm. 44,[87][88][89][90][91][92][93][94][95]. The possibility, that the observed asymmetry could be attributed to negative cooperativity in Mg 2+ binding, has been examined. The influence of the metal ion content on the catalytic properties of APase from E. coli has been examined by kinetic analyses. An activation study has indicated that Mg 2+ enhances APase activity by a mechanism that involves interactions between subunits. The observed deviations from Michaelis-Menten kinetics are independent of saturation with Zn 2+ or Mg 2+ ions, suggesting that asymmetry is an intrinsic property of the dimeric enzyme. In accordance with the experimental data, a model describing the mechanism of substrate hydrolysis by APase has been proposed. The release of the product is enhanced by a conformational change generating a subunit with lower affinity for both the substrate and the product. In the course of the catalytic cycle the conformation of the subunits alternates between two states in order to enable substrate binding and product release. APase displays higher activity in the presence of Mg 2+ , as binding of Mg 2+ increases the rate of conformational change. A conformationally controlled and Mg 2+ -assisted dissociation of the reaction product (P i ) could serve as a kinetic switch preventing loss of P i into the environment.Keywords: metalloenzymes; conformational change; subunit interactions; enzyme asymmetry; phosphate metabolism.Most unresolved questions, relating to the catalytic mechanism of alkaline phosphatase (APase, E.C. 3.1.3.1), concern the influence of conformational changes and allosteric interactions on catalytic efficiency. Crystallographic analysis has shown that APase from E. coli has three metal binding sites [1]. Both zinc ions in the active site are essential for activity [2], whereas magnesium alone does not activate the apoenzyme but increases the activity of the Zn 2+ -containing APase [3,4]. Significant cooperative interactions have been detected during metal-ion binding, positive for the binding of Zn 2+ to the M1 site, and negative for the binding of the activating cations to the M3 site [5,6]. Phosphomonoester hydrolysis and transphosphorylation, catalyzed by APase, proceeds through a covalent serine-phosphate intermediate [7,8]. Dissociation of the reaction product, P i , is rate limiting at alkaline pH.In the case of P i hydrolysis, phosphorylation of Ser102 is slow enough to become the rate-determining step [9]. APase activity increases in the presence of phosphateaccepting alcohols. The rate of P i formation is unchanged, indicating that the newly generated phosphomonoester dissociates much faster than P i . It has been suggested that P i is bound to the active site in form of a dianion [9], however, ...

f One hundred sixty-nine nonreplicate imipenem-resistant Pseudomonas aeruginosa strains isolated in a large hospital on the coastal region of Croatia were studied. The most active antibiotics were colistin and amikacin. Most of the isolates were multiresistant. The most prevalent serotype was O12, followed by O11. Six strains carried the bla VIM-2 gene located in a novel class 1 integron composed in its variable part of the bla VIM-2 -bla oxa-10 -⌬qacF-aacA4 genes. Metallo-␤-lactamase-producing strains belonged to sequence types ST235 and ST111.

The first data substantiating the occurrence of diarrhetic shellfish poisoning (DSP) in the central region of the Adriatic Sea (Kaštela Bay) in the summer of 1995 is presented. Toxicity was investigated using bio-assay and HPLC-FD analysis. Analysis of samples displaying toxicity, in addition to small concentrations of okadaic acid (OA), suggested the presence of an unknown derivatized compound at high concentration. A long term survey of the phytoplankton community has been conducted. The origin of mussel toxicity was traced to Dinophysis sacculus, a suspected toxic species.