Biocontrol potential of entomopathogenic nematodes against nut and orchard pests

Semi-field and field experiments were carried out to evaluate the biological control potential of entomopathogenic nematodes (EPNs) against grubs in hazelnut, chestnut and cherry orchards. Mortality of hazelnut weevils in interred containers treated with 2.2x106 infective juveniles (IJ) m-2 of Heterorhabditis bacteriophora was 75.4%. H. indica caused 65.2% and S. feltiae 43.3% pest mortality, but numbers were not significantly different from the untreated control (33.4%). Mortality of the chestnut weevil was slightly increased in S. carpocapsae (2x106 IJ m-2) treated containers (44.6%) compared to untreated control containers (39.2%), but differences were either not significant. Soil applications against the European cherry fruit fly did not lead to any pest control effect and we suggest that there is little potential for EPNs to control this key insect pest of sweet cherries

Na+ absorption by Claudius’ cells is regulated by purinergic signaling in the cochlea

Conclusion: Claudius’ cells absorb Na+ through the amiloride-sensitive epithelial sodium channel (ENaC). Transepithelial ion transport through ENaC and possibly a Cl[superscript]- secretory pathway is regulated by P2Y purinergic signaling. Objectives: The purpose of this study was to investigate the ion transport in the Claudius’ cells and its purinergic regulation. Method: Young adult Sprague–Dawley rats and gerbils were studied. The Claudius’ cell layer on the basilar membrane was dissected from the basal turn of the cochlea. The voltage-sensitive vibrating probe was used to measure transepithelial short circuit current (I[subscript]sc). The baseline I[subscript]sc of Claudius’ cells was measured in the perilymph-like control solution and the change of Isc after application of amiloride (10 μM) or uridine triphosphate (UTP, 100 μM). Results: A negative baseline I[subscript]sc was observed in the control solution (-12.50 ± 3.95 μA/cm[superscript]2, n=8) and the addition of amiloride resulted in a decrease of I[subscript]sc by 75.8%. The application of UTP, an agonist for P2Y purinergic receptors, led to a partial inhibition of Isc (by 38.2 ± 3.2%, n=5), and subsequent addition of amiloride abolished the remaining I[subscript]sc

A novel vasopressin-induced transcript promotes MAP kinase activation and ENaC downregulation

In the principal cell of the renal collecting duct, vasopressin regulates the expression of a gene network responsible for sodium and water reabsorption through the regulation of the water channel and the epithelial sodium channel (ENaC). We have recently identified a novel vasopressin-induced transcript (VIT32) that encodes for a 142 amino acid vasopressin-induced protein (VIP32), which has no homology with any protein of known function. The Xenopus oocyte expression system revealed two functions: (i) when injected alone, VIT32 cRNA rapidly induces oocyte meiotic maturation through the activation of the maturation promoting factor, the amphibian homolog of the universal M phase trigger Cdc2/cyclin; and (ii) when co-injected with the ENaC, VIT32 cRNA selectively downregulates channel activity, but not channel cell surface expression. In the kidney principal cell, VIP32 may be involved in the downregulation of transepithelial sodium transport observed within a few hours after vasopressin treatment. VIP32 belongs to a novel gene family ubiquitously expressed in oocyte and somatic cells that may be involved in G to M transition and cell cycling