Use of Amplified Ribosomal DNA Restriction Analysis for Identification of Ralstonia and Pandoraea Species: Interest in Determination of the Respiratory Bacterial Flora in Patients with Cystic Fibrosis

The recovery of Ralstonia and Pandoraea species from respiratory tract cultures of patients with cystic fibrosis has recently been reported. These species are difficult to identify, and especially to differentiate from Burkholderia cepacia complex organisms, with classical methods. The discriminatory power of amplified ribosomal DNA restriction analysis (ARDRA) within the two genera was assessed by comparing the restriction profiles of reference strains of each species by using a panel of six enzymes already proven suitable for the identification of Burkholderia species. ARDRA provided differentiation of all the Ralstonia species tested and of Pandoraea norimbergensis. Pandoraea species P. pnomenusa, P. sputorum, P. pulmonicola, and P. apista were not discriminated to the species level. This method allowed the identification of five clinical isolates recovered from French cystic fibrosis patients as Ralstonia mannitolilytica

Prevalence of legitimate pollinators and nectar robbers and the consequences for fruit set in an Antirrhinum majus hybrid zone

Pollinators display a remarkable diversity of foraging strategies with flowering plants, from primarily mutualistic interactions to cheating through nectar robbery. Despite numerous studies on the effect of nectar robbing on components of plant fitness, its contribution to reproductive isolation is unclear. We experimentally tested the impact of different pollinator strategies in a natural hybrid zone between two subspecies of Antirrhinum majus with alternate flower colour guides. On either side of a steep cline in flower colour between Antirrhinum majus pseudomajus (magenta) and A. m. striatum (yellow), we quantified the behaviour of all floral visitors at different time points during the flowering season. Using long-run camera surveys, we quantify the impact of nectar robbing on the number of flowers visited per inflorescence and the flower probing time. We further experimentally tested the effect of nectar robbing on female reproductive success by manipulating the intensity of robbing. While robbing increased over time the number of legitimate visitors tended to decrease concomitantly. We found that the number of flowers pollinated on a focal inflorescence decreased with the number of prior robbing events. However, in the manipulative experiment, fruit set and fruit volume did not vary significantly between low robbing and control treatments. Our findings challenge the idea that robbers have a negative impact on plant fitness through female function. This study also adds to our understanding of the components of pollinator-mediated reproductive isolation and the maintenance of Antirrhinum hybrid zones

The negative regulator of Gli, Suppressor of fused (Sufu), interacts with SAP18, Galectin3 and other nuclear proteins.

Sufu (Suppressor of fused) is a negative regulator of the Hedgehog signal-transduction pathway, interacting directly with the Gli family of transcription factors. However, its function remains poorly understood. In the present study, we determined the expression, tissue distribution and biochemical properties of mSufu (mouse Sufu) protein. We identified several mSufu variants of which some were phosphorylated. A yeast two-hybrid screen with mSufu as bait allowed us to identify several nuclear proteins as potential partners of mSufu. Most of these partners, such as SAP18 (Sin3-associated polypeptide 18), pCIP (p300/CBP-cointegrator protein) and PIAS1 (protein inhibitor of activated signal transduction and activators of transcription 1), are involved in either repression or activation of transcription and two of them, Galectin3 and hnRNPA1 (heterogeneous nuclear ribonucleoprotein A1), have a nuclear function in pre-mRNA splicing. We confirmed the mSufu-SAP18 and mSufu-Galectin3 interactions by independent biochemical assays. Using a cell transfection assay, we also demonstrated that mSufu protein (484 amino acids) is predominantly cytoplasmic but becomes mostly nuclear when a putative nuclear export signal is mutated or after treatment of the cells with leptomycin B. Moreover, mSufu is translocated to the nucleus when co-expressed with SAP18, which is normally found in this compartment. In contrast, Galectin3 is translocated to the cytoplasm when it is co-expressed with mSufu. Our findings indicate that mSufu is a shuttle protein that appears to be extremely versatile in its ability to bind different proteins in both the cytoplasm and nucleus

Study of nicotinic acetylcholine receptors on cultured antennal lobe neurones from adult honeybee brains.

In insects, acetylcholine (ACh) is the main neurotransmitter, and nicotinic acetylcholine receptors (nAChRs) mediate fast cholinergic synaptic transmission. In the honeybee, nAChRs are expressed in diverse structures including the primary olfactory centres of the brain, the antennal lobes (AL) and the mushroom bodies. Whole-cell, voltage-clamp recordings were used to characterize the nAChRs present on cultured AL cells from adult honeybee, Apis mellifera. In 90% of the cells, applications of ACh induced fast inward currents that desensitized slowly. The classical nicotinic agonists nicotine and imidacloprid elicited respectively 45 and 43% of the maximum ACh-induced currents. The ACh-elicited currents were blocked by nicotinic antagonists methyllycaconitine, dihydroxy-beta-erythroidine and alpha-bungarotoxin. The nAChRs on adult AL cells are cation permeable channels. Our data indicate the existence of functional nAChRs on adult AL cells that differ from nAChRs on pupal Kenyon cells from mushroom bodies by their pharmacological profile and ionic permeability, suggesting that these receptors could be implicated in different functions