Reproductive traits of the freshwater oyster Etheria elliptica (Bivalvia: Etheriidae) in the Pendjari River,Benin: implications for conservation

The African freshwater oyster Etheria elliptica, which is of great economic importance throughout the continent, is facing overharvesting in many fisheries in West Africa. Its reproductive traits (sex ratio, size at sexual maturity, oocyte diameter and fecundity) were studied at four stations located along the Pendjari River, northern Benin, in April 2013. Histological techniques were implemented to identify sex and gonad development stages. Oocyte sizes were measured based on the histological images and mean oocyte diameter was 38 µm. Fecundity, estimated by counting the developing eggs, averaged 106 724 eggs and increased significantly with shell size. The average sex ratio was approximately 1:1. Hermaphrodites were rare. Males reached sexual maturity at 57.6 mm dorsoventral height, earlier than females at 64.7 mm. The majority of the oyster specimens were in ripe-spawning stages, indicating that reproductive activities partly took place towards the end of the dry season. Both mature and immature individuals were subjected to harvesting at all the investigated fishing sites. The mean size of exploited oysters was 60.6 mm, lower than the size of females at maturity. Management strategies must enforce the minimum size of 65 mm required for harvesting, particularly in open access sites where juveniles are mostly harvested.     

Intraspecific DNA divergence in Drosophila: a study on parthenogenetic D. mercatorum

Drosophila mercatorum is a species that can give rise to totally homozygous parthenogenetic strains. Using the technique of DNA-DNA hybridization, we have assessed the overall single-copy DNA differences among three independently derived strains that represent three independent genomes. Among strains, the average difference between homoduplex and heteroduplex median melting temperatures is 1.3 degrees C. This represents greater than or equal to 1.3% base-pair mismatch. Normalized percent of reassociation indicates further genetic differences, probably reflecting insertion/deletion differences and/or regions of the genome that are highly variable. This overall intraspecific genetic variation is higher than generally is thought to exist but is consistent with growing evidence of extensive DNA diversity within species of invertebrates. High intraspecific DNA variation may be correlated with rapid phyletic rates of evolution. Because of this high level of variation, the technique of DNA-DNA hybridization may be used to study intraspecific variation in invertebrates but is limited in its usefulness for higher systematic studies.      

Helicobacter pylori‐derived neutrophil‐activating protein increases the lifespan of monocytes and neutrophils

An invariable feature of Helicobacter pylori‐infected gastric mucosa is the persistent infiltration of inflammatory cells. The neutrophil‐activating protein (HP‐NAP) has a pivotal role in triggering and orchestrating the phlogistic process associated with H. pylori infection. Aim of this study was to address whether HP‐NAP might further contribute to the inflammation by increasing the lifespan of inflammatory cells. We report that HP‐NAP is able to prolong the lifespan of monocytes, in parallel with the induction of the anti‐apoptotic proteins A1, Mcl‐1, Bcl‐2 and Bcl‐X_L. This effect does not result from a direct action on the apoptotic machinery, but rather it requires the release of endogenous pro‐survival factors, such as interleukin‐1β, which probably acts in synergy with other unidentified mediators. We also report that HP‐NAP promotes the survival of Ficoll‐purified neutrophils in a monocyte‐dependent fashion: indeed, mononuclear cell depletion of Ficoll‐purified neutrophils completely abolished the pro‐survival effect by HP‐NAP. In conclusion, our data reinforce the notion that HP‐NAP has a pivotal role in sustaining a prolonged activation of myeloid cells.     

Object Discrimination Reversal As a Method to Assess Cognitive Impairment in Nonhuman Primate Enhanced Pre‐ and Postnatal Developmental (ePPND) Studies: Statistical Power Analysis

An important aspect of the enhanced pre‐ and postnatal developmental (ePPND) toxicity study in nonhuman primates (NHP) is that it combines in utero and postnatal assessments in a single study. However, it is unclear if NHP ePPND studies are suitable to perform all of the evaluations incorporated into rodent PPND studies. To understand the value of including cognitive assessment in a NHP ePPND toxicity study, we performed a power analysis of object discrimination reversal task data using a modified Wisconsin General Testing Apparatus (ODR‐WGTA) from two NHP ePPND studies. ODR‐WGTA endpoints evaluated were days to learning and to first reversal, and number of reversals. With α = 0.05 and a one‐sided t‐test, a sample of seven provided 80% power to predict a 100% increase in all three of the ODR‐WGTA endpoints; a sample of 25 provided 80% power to predict a 50% increase. Similar power analyses were performed with data from the Cincinnati Water Maze (CWM) and passive avoidance tests from three rat PPND toxicity studies. Groups of 5 and 15 in the CWM and passive avoidance test, respectively, provided 80% power to detect a 100% change. While the power of the CWM is not far superior to the NHP ODR‐WGTA, a clear advantage is the routine use of larger sample size, with a group of 20 rats the CWM provides ～90% power to detect a 50% change. Due to the limitations on the number of animals, the ODR‐WGTA may not be suitable for assessing cognitive impairment in NHP ePPND studies.     

The neutrophil-activating protein of Helicobacter pylori (HP-NAP) as an immune modulating agent

During evolution microorganisms have developed several immune modulating strategies. The Helicobacter pylori neutrophil-activating protein (HP-NAP) is a virulence factor that attracts and activates neutrophils, and promotes their endothelial adhesion and the production of oxygen radicals and chemokines, including CXCL8, CCL3 and CCL4. HP-NAP, a TLR2 agonist, is an immune modulator able to induce the expression of interleukin-12 (IL-12) and IL-23 by human neutrophils and monocytes. In fact, HP-NAP has the potential to shift antigen-specific T-cell responses from a predominant Th2 to a polarized Th1 cytotoxic phenotype, characterized by high levels of interferon-gamma and tumor necrosis factor-alpha production. Thus, HP-NAP is a key factor driving Th1 inflammation in H. pylori infection and may be a new tool for future therapeutic strategies aimed at redirecting Th2 into Th1 responses, for example in atopy, vaccinology and cancer immunotherapy.