Characterization of the Holliday Junction Resolving Enzyme Encoded by the Bacillus subtilis Bacteriophage SPP1

Recombination-dependent DNA replication, which is a central component of viral replication restart, is poorly understood in Firmicutes bacteriophages. Phage SPP1 initiates unidirectional theta DNA replication from a discrete replication origin (oriL), and when replication progresses, the fork might stall by the binding of the origin binding protein G38P to the late replication origin (oriR). Replication restart is dependent on viral recombination proteins to synthesize a linear head-to-tail concatemer, which is the substrate for viral DNA packaging. To identify new functions involved in this process, uncharacterized genes from phage SPP1 were analyzed. Immediately after infection, SPP1 transcribes a number of genes involved in recombination and replication from P _E2 and P _E3 promoters. Resequencing the region corresponding to the last two hypothetical genes transcribed from the P _E2 operon (genes 44 and 45) showed that they are in fact a single gene, re-annotated here as gene 44, that encodes a single polypeptide, named gene 44 product (G44P, 27.5 kDa). G44P shares a low but significant degree of identity in its C-terminal region with virus-encoded RusA-like resolvases. The data presented here demonstrate that G44P, which is a dimer in solution, binds with high affinity but without sequence specificity to several double-stranded DNA recombination intermediates. G44P preferentially cleaves Holliday junctions, but also, with lower efficiency, replicated D-loops. It also partially complemented the loss of RecU resolvase activity in B. subtilis cells. These in vitro and in vivo data suggest a role for G44P in replication restart during the transition to concatemeric viral replication.     

Ants as mealybug detectors: a novel tool for monitoring Planococcus ficus infestation based on ant behaviour

1. Vineyards are economically valuable agroecosystems that have spread to all continents. As such, sustainable management of their pests is an important goal. Mealybugs are serious pests of vines with Planococcus ficus (VMB) being the most problematic worldwide. Mealybugs are attended by different ant species, whose trophobiotic relationship is often considered damaging since some ant species may offer effective protection from natural enemies in exchange for honeydew.
2. We tested whether this trophobiosis can be used as a VMB monitoring tool, developing a protocol to evaluate infestation on the plants based on ant behaviour (Ant method). We compared this new protocol with the conventional one, consisting in visual counting of VMBs on infested leaves (Leaf method).
3. Our results demonstrated that the Ant method yielded significant advantages over the Leaf method by: (i) allowing to detect VMB infestation on individual plants much earlier; and (ii) allowing to keep track of VMB presence after pest treatments.
4. The Ant method is proposed as a valid complementary tool for integrated pest management in vineyards and its successful achievement encourage searching for further agricultural contexts in which ants may be revaluated as a monitoring tool.

     

Two new cases of cutaneous alternariosis with a review of the literature

Summary Two cases of cutaneous phaeohyphomycosis due to Alternaria tenuissima in patients affected with primitive myeloproliferative syndrome and lymphocytic lymphoma respectively are reported.Following a review of the specific literature, the authors discuss the etiopathogenic mechanisms, the clinical and histologic aspects of the lesions and the therapeutic problems.     

Fructose-1,6-diphosphate as an in vitro and in vivo anti-alcohol agent in the rat

Fructose-1, 6-diphosphate (FDP) decreases the effect of ethanol on Ca++ entry and inhibits the ethanol-stimulated phosphate efflux in rat heart slices. FDP also inhibits the ethanol-stimulated [36Cl-]-uptake by rat brain microvesicles and affects the isolated GABA-receptor in a way opposite to that of ethanol. The in vivo effects of FDP include a dose-dependent decrease in ethanol-induced gastric ulcers and a decrease in the serum transaminase levels raised by chronic ethanol administration. Other central actions of ethanol such as diuresis, narcosis, dependence and withdrawal symptoms are also counteracted by FDP.