Enhancing knowledge on low-value fishing species: the distinct reproductive strategy of two gurnard species.

The depletion and overexploitation of several fish stock demands for a valorisation of non-target and discarded species. Nonetheless, such species are often poorly studied, and information on their biological parameters must be gathered for effective population management. For 1 year, the reproductive strategy of the piper gurnard Trigla lyra and the red gurnard Chelidonichthys cuculus was studied by monthly samples obtained from commercial boats operating on western Portuguese coast. Both species showed a biased sex ratio towards females, especially for larger length classes. Length at first maturity could be estimated only for red gurnard (22.1 and 19.9 cm for females and males, respectively) because all piper gurnard individuals caught were mature. Piper gurnard showed determinate fecundity and a short spawning season, from November to February with a peak in January, whereas red gurnard showed indeterminate fecundity and a wide spawning season, from late December to May. The relative annual fecundity estimated for red gurnard (1893 ± 728 oocytes × g-1 eviscerated weight [EW]) was higher than the one estimated for piper gurnard (1018 ± 250 oocytes×g-1 EW). Although important information for understanding the species dynamics is presented in this study, additional information on other life-history parameters and of species landings is required.

Genome-wide identification of genes involved in the positive and negative regulation of acetic acid-induced programmed cell death in Saccharomyces cerevisiae.

BACKGROUND: Acetic acid is mostly known as a toxic by-product of alcoholic fermentation carried out by Saccharomyces cerevisiae, which it frequently impairs. The more recent finding that acetic acid triggers apoptotic programmed cell death (PCD) in yeast sparked an interest to develop strategies to modulate this process, to improve several biotechnological applications, but also for biomedical research. Indeed, acetate can trigger apoptosis in cancer cells, suggesting its exploitation as an anticancer compound. Therefore, we aimed to identify genes involved in the positive and negative regulation of acetic acid-induced PCD by optimizing a functional analysis of a yeast Euroscarf knock-out mutant collection. RESULTS: The screen consisted of exposing the mutant strains to acetic acid in YPD medium, pH 3.0, in 96-well plates, and subsequently evaluating the presence of culturable cells at different time points. Several functional categories emerged as greatly relevant for modulation of acetic acid-induced PCD (e.g.: mitochondrial function, transcription of glucose-repressed genes, protein synthesis and modifications, and vesicular traffic for protection, or amino acid transport and biosynthesis, oxidative stress response, cell growth and differentiation, protein phosphorylation and histone deacetylation for its execution). Known pro-apoptotic and anti-apoptotic genes were found, validating the approach developed. Metabolism stood out as a main regulator of this process, since impairment of major carbohydrate metabolic pathways conferred resistance to acetic acid-induced PCD. Among these, lipid catabolism arose as one of the most significant new functions identified. The results also showed that many of the cellular and metabolic features that constitute hallmarks of tumour cells (such as higher glycolytic energetic dependence, lower mitochondrial functionality, increased cell division and metabolite synthesis) confer sensitivity to acetic acid-induced PCD, potentially explaining why tumour cells are more susceptible to acetate than untransformed cells and reinforcing the interest in exploiting this acid in cancer therapy. Furthermore, our results clearly establish a connection between cell proliferation and cell death regulation, evidencing a conserved developmental role of programmed cell death in unicellular eukaryotes. CONCLUSIONS: This work advanced the characterization of acetic acid-induced PCD, providing a wealth of new information on putative molecular targets for its control with impact both in biotechnology and biomedicine.

Reproduction of the Blue Jack Mackerel, Trachurus picturatus, in Western Portugal: Microscopic Gonad Analysis Reveals Indeterminate Fecundity and Skipped Spawning Patterns.

Blue jack mackerel, Trachurus picturatus, is the fifth most landed fish species in mainland Portugal, but information on its reproductive biology is scarce. From September 2018 to August 2019, 626 specimens were collected from commercial vessels to clarify the reproductive strategy of the T. picturatus population off the west coast of Portugal. The proportion and length range of males and females were similar. Only three of the specimens collected were categorized as immature, indicating that the fish caught in the fishery are primarily mature. The spawning season lasted from late January until the end of March, with gonadosomatic indices being similar for males and females. Fecundity was indeterminate, and estimated batch fecundity ranged between 6,798 (at 25.4 cm TL) and 302,358 oocytes (at 33.8 cm TL). The low number of females showing direct evidence of imminent or recent spawning suggests a low number of spawning events. In addition, 12.7% of females were considered non-reproductive due to ovary abnormalities including parasitic infection by Kudoa species, atretic structures and skipped spawning events. This study highlights the importance of accounting for skipped spawning events and ovary abnormalities in the management of species fisheries.