Hematodinium sp. infection in Norway lobster Nephrops norvegicus and its effects on meat quality

Hematodinium and Hematodinium-like species have emerged in the last 3 decades as important parasitic pathogens of crustaceans worldwide, causing a significant economic loss to fisheries and related markets. In some species (notably the Tanner crab Chionoecetes bairdi), the parasite reportedly causes the cooked meat to taste bitter and aspirin-like. The bitter taste, together with the gross pathology of the infection, renders these crabs unmarketable. Surprisingly, no organoleptic tests have ever been conducted to date, and the cause for the bitter taste is still unknown. Nevertheless, it is generally assumed that the bitter taste occurs widely in cooked meats and products derived from crustaceans infected with Hematodinium. In the present study, we analysed the meat quality and organoleptic attributes after capture and during storage of Norway lobsters Nephrops norvegicus from Scottish waters that were either asymptomatic or symptomatic of patent Hematodinium infection. Results from the sensory evaluation of the cooked product indicate that tail meat from symptomatic N. norvegicus is bland in flavour and aftertaste, and more friable or sloppier in texture than meat from asymptomatic animals. As a consequence, infected meat tends to be less palatable, although surprisingly no bitter taste is reported. From an analytical point of view, tail meat from patently infected animals is at an advanced stage of auto - lysis, while no difference in microbial load is detected. These results suggest that Norway lobsters heavily infected with Hematodinium are of inferior marketing quality even after the tails have been cooked

On the occurrence of Iphiculus eliasi Hyzny & Gross, 2016 (Decapoda, Brachyura, Leucosioidea) from the Miocene of Catalonia (northeastern Iberian Peninsula)

Recovery of two specimens of leucosioid crabs in Langhian (middle Miocene) strata at Vilafranca del Penedes (Alt Penedes, Catalonia) and a re-examination of another leucosioid from the palaeontological collections of the Vinseum (Vilafranca del Penedes, Catalonia) have led us to consider all of these as conspecific with Iphiculus eliasi Hyzny & Gross, 2016, described first from the middle Miocene of Austria. The sternal and pleonal remains preserved in one of the Catalonian specimens allows to emend the original description of the species. Likewise, a specimen from the middle Miocene of Portugal, previously described as a paguroid, is herein transferred to this species. The occurrence of I. eliasi, either in outcrops along the northeastern and southwestern coasts of the Iberian Peninsula, corroborates the close relationship between decapod assemblages which inhabited similar palaeoenvironments in the Central Paratethys, the western Mediterranean and even the nearest Atlantic waters, during the middle Miocene

Retinol Metabolism in the Mollusk Osilinus lineatus Indicates an Ancient Origin for Retinyl Ester Storage Capacity

Although retinoids have been reported to be present and active in vertebrates and invertebrates, the presence of mechanisms for retinoid storage in the form of retinyl esters, a key feature to maintain whole-organism retinoid homeostasis, have been considered to date a vertebrate innovation. Here we demonstrate for the first time the presence of retinol and retinyl esters in an invertebrate lophotrochozoan species, the gastropod mollusk Osilinus lineatus. Furthermore, through a pharmacological approach consisting of intramuscular injections of different retinoid precursors, we also demonstrate that the retinol esterification pathway is active in vivo in this species. Interestingly, retinol and retinyl esters were only detected in males, suggesting a gender-specific role for these compounds in the testis. Females, although lacking detectable levels of retinol or retinyl esters, also have the biochemical capacity to esterify retinol, but at a lower rate than males. The occurrence of retinyl ester storage capacity, together with the presence in males and females of active retinoids, i.e., retinoic acid isomers, indicates that O. lineatus has a well developed retinoid system. Hence, the present data strongly suggest that the capacity to maintain retinoid homeostasis has arisen earlier in Bilateria evolution than previously thought

Proteomics as a quality control tool of pharmaceutical probiotic bacterial lysate products

Probiotic bacteria have a wide range of applications in veterinary and human therapeutics. Inactivated probiotics are complex samples and quality control (QC) should measure as many molecular features as possible. Capillary electrophoresis coupled to mass spectrometry (CE/MS) has been used as a multidimensional and high throughput method for the identification and validation of biomarkers of disease in complex biological samples such as biofluids. In this study we evaluate the suitability of CE/MS to measure the consistency of different lots of the probiotic formulation Pro-Symbioflor which is a bacterial lysate of heat-inactivated Escherichia coli and Enterococcus faecalis. Over 5000 peptides were detected by CE/MS in 5 different lots of the bacterial lysate and in a sample of culture medium. 71 to 75% of the total peptide content was identical in all lots. This percentage increased to 87–89% when allowing the absence of a peptide in one of the 5 samples. These results, based on over 2000 peptides, suggest high similarity of the 5 different lots. Sequence analysis identified peptides of both E. coli and E. faecalis and peptides originating from the culture medium, thus confirming the presence of the strains in the formulation. Ontology analysis suggested that the majority of the peptides identified for E. coli originated from the cell membrane or the fimbrium, while peptides identified for E. faecalis were enriched for peptides originating from the cytoplasm. The bacterial lysate peptides as a whole are recognised as highly conserved molecular patterns by the innate immune system as microbe associated molecular pattern (MAMP). Sequence analysis also identified the presence of soybean, yeast and casein protein fragments that are part of the formulation of the culture medium. In conclusion CE/MS seems an appropriate QC tool to analyze complex biological products such as inactivated probiotic formulations and allows determining the similarity between lots

Endoplasmic reticulum stress as a key mechanism in stunted growth of seawater rainbow trout (Oncorhynchus mykiss)

Background Rainbow trout (Oncorhynchus mykiss) is a salmonid species with a complex life-history. Wild populations are naturally divided into freshwater residents and sea-run migrants. Migrants undergo an energy-demanding adaptation for life in seawater, known as smoltification, while freshwater residents display these changes in an attenuated magnitude and rate. Despite this, in seawater rainbow trout farming all fish are transferred to seawater. Under these circumstances, weeks after seawater transfer, a significant portion of the fish die (around 10%) or experience growth stunting (GS; around 10%), which represents an important profitability and welfare issue. The underlying causes leading to GS in seawater-transferred rainbow trout remain unknown. In this study, we aimed at characterising the GS phenotype in seawater-transferred rainbow trout using untargeted and targeted approaches. To this end, the liver proteome (LC-MS/MS) and lipidome (LC-MS) of GS and fast-growing phenotypes were profiled to identify molecules and processes that are characteristic of the GS phenotype. Moreover, the transcription, abundance or activity of key proteins and hormones related to osmoregulation (Gill Na+, K + –ATPase activity), growth (plasma IGF-I, and liver igf1, igfbp1b, ghr1 and ctsl) and stress (plasma cortisol) were measured using targeted approaches. Results No differences in Gill Na+, K + –ATPase activity and plasma cortisol were detected between the two groups. However, a significant downregulation in plasma IGF-I and liver igf1 transcription pointed at this growth factor as an important pathomechanism for GS. Changes in the liver proteome revealed reactive-oxygen-species-mediated endoplasmic reticulum stress as a key mechanism underlying the GS phenotype. From the lipidomic analysis, key observations include a reduction in triacylglycerols and elevated amounts of cardiolipins, a characteristic lipid class associated with oxidative stress, in GS phenotype. Conclusion While the triggers to the activation of endoplasmic reticulum stress are still unknown, data from this study point towards a nutritional deficiency as an underlying driver of this phenotype

Inferring fish escape behaviour in trawls based on catch comparison data: Model development and evaluation based on data from Skagerrak, Denmark

During the fishing process, fish react to a trawl with a series of behaviours that often are species and size specific. Thus, a thorough understanding of fish behaviour in relation to fishing gear and a scientific understanding of the ability of different gear designs to utilize or stimulate various behavioural patterns during the catching process are essential for developing more efficient, selective, and environmentally friendly trawls. Although many behavioural studies using optical and acoustic observation systems have been conducted, harsh observation conditions on the fishing grounds often hamper the ability to directly observe fish behaviour in relation to fishing gear. As an alternative to optical and acoustic methods, we developed and applied a new mathematical model to catch data to extract detailed and quantitative information about species- and size-dependent escape behaviour in towed fishing gear such as trawls. We used catch comparison data collected with a twin trawl setup; the only difference between the two trawls was that a 12 m long upper section was replaced with 800 mm diamond meshes in one of them. We investigated the length-based escape behaviour of cod (Gadus morhua), haddock (Melanogrammus aeglefinus), saithe (Pollachius virens), witch flounder (Glyptocephalus cynoglossus), and lemon sole (Microstomus kitt) and quantified the extent to which behavioural responses set limits for the large mesh panel's selective efficiency. Around 85% of saithe, 80% of haddock, 44% of witch flounder, 55% of lemon sole, and 55% of cod (below 68 cm) contacted the large mesh panel and escaped. We also demonstrated the need to account for potential selectivity in the trawl body, as it can bias the assessment of length-based escape behaviour. Our indirect assessment of fish behaviour was in agreement with the direct observations made for the same species in a similar section of the trawl body reported in the literature