A map of brain neuropils and fiber systems in the ant Cardiocondyla obscurior.

A wide spectrum of occupied ecological niches and spectacular morphological adaptations make social insects a prime object for comparative neuroanatomical studies. Eusocial insects have evolved complex societies based on caste polyphenism. A diverse behavioral repertoire of morphologically distinct castes of the same species requires a high degree of plasticity in the central nervous system. We have analyzed the central brain neuropils and fiber tract systems of the worker of the ant Cardiocondyla obscurior, a model for the study of social traits. Our analysis is based on whole mount preparations of adult brains labeled with an antibody against Drosophila-Synapsin, which cross-reacts strongly with synapses in Cardiocondyla. Neuropil compartments stand out as domains with a certain texture and intensity of the anti-Synapsin signal. By contrast, fiber tracts, which are composed of bundles of axons accompanied by glia and are devoid of synapses, appear as channels or sheaths with low anti-Synapsin signal. We have generated a digital 3D atlas of the Cardiocondyla brain neuropil. The atlas provides a reference for future studies of brain polymorphisms in distinct castes, brain development or localization of neurotransmitter systems.

Evaluation of a multiplex-PCR detection in combination with an isolation method for STEC O26, O103, O111, O145 and sorbitol fermenting O157 in food.

The aim of the current study was to evaluate a multiplex PCR (mPCR) detection test combined with the evaluation of a previously described isolation method. Minced beef, raw-milk cheese and sprouted seed samples were inoculated with low amounts (7-58 cfu 25 g(-1)) of non-stressed, cold-stressed or freeze-stressed clinical STEC strains, including serogroups O26, O103, O111, O145, sorbitol fermenting (SF) O157 and non-sorbitol fermenting (NSF) O157. The inoculated pathogen was detected using a 24 h-enrichment followed by an mPCR protocol, and in parallel isolated using an enrichment step of 6 and 24 h, followed by selective plating of the enriched broth and selective plating of the immunomagnetic separation (IMS) product. Recovery results were evaluated and compared. Successful mPCR detection and isolation was obtained for non-stressed and cold-stressed STEC cells in minced beef and raw-milk cheese samples, except for serogroups O111 and SF O157. For freeze-stressed cells and sprouted seed samples, false negatives were often found. Isolation was better after 24 h-enrichment compared to 6 h-enrichment. IMS improved in some cases the isolation of non-stressed and cold-stressed cells belonging to serogroups O111 and O157 from minced beef and raw-milk cheese and freeze-stressed cells of all tested serogroups from minced beef.

Occurrence and virulence patterns of E. coli O26, O103, O111 and O145 in slaughter cattle.

The study attempted to investigate the occurrence of non-O157 E. coli serogroups O26, O103, O111 and O145 in cattle at slaughter and to determine the virulence potential of these isolates. A total of 399 fecal samples were analyzed by selective plating and E. coli isolates were characterized by polymerase chain reaction (PCR) for the genes vtx1, vtx2, eae and EHEC hlyA. Immunomagnetic separation (IMS) is required to increase the efficiency of the isolation procedure. E. coli O26, O103, O111 and O145 were recovered from 24 (6%) fecal samples. E. coli O26 and O103 seemed to be more abundant in slaughter cattle than E. coli O111 and O145. Sixteen out of the 24 isolates harbored vtx genes. All vtx-positive isolates harbored one or more additional virulence factors. Six out of the 8 vtx-negative isolates harbored eae and/or EHEC hlyA, whereas 2 strains harbored none of the tested virulence genes.