Reproductive traits of the round sardinella in the Canary Islands (Spain, NW Africa)

The present study aims to investigate the reproductive biology of the small pelagic Sardinella aurita Valenciennes, 1847 in the Canary Islands, to enable its reliable assessment and advise on appropriate management measures for a fishing resource showing a declining trend in landings. Reproductive biology and sexual patterns of round sardinella were examined from monthly random samples of commercial catches landed by the artisanal purse-seine fleet. The landings' length frequencies, ranging between 9–32 cm (based on the total lengths, TL), were recorded from 2013–2019. The overall mean value of TL was 20.9 cm, with annual mean values between 20–22 cm, except in 2016 (TL = 19 cm). The overall sex ratio M:F was 1:0.92, with males significantly predominant. Sex ratios fluctuated as a function of size and month: females were more abundant in the larger length classes, as well as before and after spawning, whereas males were more abundant in the smaller length classes and during spawning. Based on gonad maturity stages and gonadosomatic index, round sardinella spawns during almost all the year, with a peak in January–February and a resting period during October–November. The length at first maturity was estimated at TL of 18.2 cm, notably smaller than the value obtained for the NW African coastal waters where the demographic structure in round sardinellas' landings is totally different.Versión del edito

Using Mass Spectrometry to Detect, Differentiate, and Semiquantitate Closely Related Peptide Hormones in Complex Milieu: Measurement of IGF-II and Vesiculin

The search for an islet β-cell growth factor has been a key objective in recent diabetes research, since the ability to regenerate and/or protect the functioning β-cell population in patients could result in a great advancement for diabetes treatment. Insulin-like growth factor (IGF)-I and IGF-II are known to play crucial roles in fetal growth and prenatal development, and there is growing evidence that IGF-II increases β-cell proliferation and survival in vitro and in vivo. A search for the source of IGF-II-like-immunoreactivity in isolated β-cell secretory granules from the murine cell line βTC6-F7 revealed a novel two-chain IGF-II-derived peptide which we named vesiculin and which has been shown to be a full insulin agonist. Here, we present an LC-MS/MS method that enables selective detection and semi-quantitation of the highly related IGF-II and vesiculin molecules. We have used this method to measure these two peptides in conditioned media from two β-cell lines, produced under increasing glucose concentrations. This technique detected both IGF-II and vesiculin in media conditioned by MIN6 and βTC6-F7 cells at levels in the range of 0–6 μM (total insulin 80–450 μM), and revealed a glucose-stimulated increase in insulin, IGF-II and vesiculin. IGF-II was detected in adult human and neonatal mouse serum in high levels, but vesiculin was not present. The methodology we present herein has utility for detecting and differentiating active peptides that are highly related and of low abundance