KeaA, a Dictyostelium kelch-domain protein that regulates the response to stress and development

<p>Abstract</p> <p>Background</p> <p>The protein kinase YakA is responsible for the growth arrest and induction of developmental processes that occur upon starvation of <it>Dictyostelium </it>cells. <it>yakA^-</it>cells are aggregation deficient, have a faster cell cycle and are hypersensitive to oxidative and nitrosoative stress. With the aim of isolating members of the YakA pathway, suppressors of the death induced by nitrosoative stress in the <it>yakA^-</it>cells were identified. One of the suppressor mutations occurred in <it>keaA</it>, a gene identical to DG1106 and similar to Keap1 from mice and the Kelch protein from Drosophila, among others that contain Kelch domains.</p> <p>Results</p> <p>A mutation in <it>keaA </it>suppresses the hypersensitivity to oxidative and nitrosoative stresses but not the faster growth phenotype of <it>yakA^-</it>cells. The growth profile of <it>keaA </it>deficient cells indicates that this gene is necessary for growth. <it>keaA </it>deficient cells are more resistant to nitrosoative and oxidative stress and <it>keaA </it>is necessary for the production and detection of cAMP. A morphological analysis of <it>keaA </it>deficient cells during multicellular development indicated that, although the mutant is not absolutely deficient in aggregation, cells do not efficiently participate in the process. Gene expression analysis using cDNA microarrays of wild-type and <it>keaA </it>deficient cells indicated a role for KeaA in the regulation of the cell cycle and pre-starvation responses.</p> <p>Conclusions</p> <p>KeaA is required for cAMP signaling following stress. Our studies indicate a role for kelch proteins in the signaling that regulates the cell cycle and development in response to changes in the environmental conditions.</p

Assessment of the efficacy of Umonium38 on multidrug-resistant nosocomial pathogens.

INTRODUCTION: We investigated the efficacy of a biocide Umonium38 on multidrug-resistant strains by comparison with a chloride derivative (Decs). METHODS: In vitro susceptibility tests were performed by agar diffusion disk and results were interpreted according to Clinical and Laboratory Standards Institute (CLSI). In vitro antibacterial efficacy of Umonium38 and Decs over selected strains was evaluated according to European Standards protocol with or without organic substance. RESULTS: In vitro tests with Umoniumnr at 2.5% concentration demonstrated an overall drop in microbial and yeast charges after 5 min. contact without organic substance. The same results were obtained in presence of organic substance. In vitro tests with chloride derivative at 5% without organic substance also resulted in overall drop in bacterial and mycotic charges. Conversely, in presence of organic substance, the hypochlorite reduced the initial 10 UFC/ml to 10 UFC/ml for all bacterial strains with a decrease of 4 log except for Enterococcus faecalis and Candida albicans whose reduction was 2 and 1 log units respectively. DISCUSSION: The organic substance in water requires large use of oxidising disinfectants (chloride, ozone) implying in the need for higher-than-standard concentrations. The disinfecting effect of chloride is only visible when the "requirement" of organic substance has been met. By contrast, Umonium38 behaves like a powerful biocide even in presence of organic substance, as it is not "consumed" by possible organic residues. CONCLUSIONS: Umonium38 resulted beneficial and effective. It is to be stressed, however, that all these experiments were in vitro tests and still requires validation from a correct use of clinical practice

Inhibition of AdeB, AceI, and AmvA Efflux Pumps Restores Chlorhexidine and Benzalkonium Susceptibility in Acinetobacter baumannii ATCC 19606

The management of infections caused by Acinetobacter baumannii is hindered by its intrinsic tolerance to a wide variety of biocides. The aim of the study was to analyze the role of different A. baumannii efflux pumps (EPs) in tolerance to chlorhexidine (CHX) and benzalkonium (BZK) and identify non-toxic compounds, which can restore susceptibility to CHX and BZK in A. baumannii. A. baumannii ATCC 19606 strain was tolerant to both CHX and BZK with MIC and MBC value of 32 mg/L. CHX subMIC concentrations increased the expression of adeB and adeJ (RND superfamily), aceI (PACE family) and amvA (MFS superfamily) EP genes. The values of CHX MIC and MBC decreased by eightfold in ΔadeB and twofold in ΔamvA or ΔaceI mutants, respectively, while not affected in ΔadeJ mutant; EPs double and triple deletion mutants showed an additive effect on CHX MIC. CHX susceptibility was restored in double and triple deletion mutants with inactivation of adeB gene. BZK MIC was decreased by fourfold in ΔadeB mutant, and twofold in ΔamvA and ΔaceI mutants, respectively; EPs double and triple deletion mutants showed an additive effect on BZK MIC. BZK susceptibility was recovered in ΔadeB ΔaceI ΔadeJ and ΔamvA ΔadeB ΔadeJ triple mutants. The structural comparison of AdeB and AdeJ protomers showed a more negatively charged entrance binding site and F-loop in AdeB, which may favor the transport of CHX. The carbonyl cyanide m-chlorophenylhydrazine protonophore (CCCP) EP inhibitor reduced dose-dependently CHX MIC in A. baumannii ATCC 19606 and in ΔadeJ, ΔaceI, or ΔamvA mutants, but not in ΔadeB mutant. Either piperine (PIP) or resveratrol (RV) at non-toxic concentrations inhibited CHX MIC in A. baumannii ATCC 19606 parental strain and EPs gene deletion mutants, and CHX-induced EP gene expression. Also, RV inhibited BZK MIC and EP genes expression in A. baumannii ATCC 19606 parental strain and EPs mutants. These results demonstrate that tolerance to CHX and BZK in A. baumannii is mediated by the activation of AdeB, AceI and AmvA EPs, AdeB playing a major role. Importantly, inhibition of EP genes expression by RV restores CHX and BZK susceptibility in A. baumannii

Histopathologic Evaluation of Intralabyrinthine Schwannoma

Objectives: The aim of this study is to perform a histopathologic analysis of temporal bones with an intralabyrinthine schwannoma (ILS) in order to characterize its extension. Methods: Archival temporal bones with a diagnosis of sporadic schwannoma were identified. Both symptomatic and occult nonoperated ILS were included for further analysis. Results: A total of 6 ILS were identified, with 4 intracochlear and 2 intravestibular schwannomas. All intracochlear schwannomas involved the osseous spiral lamina, with 2 extending into the modiolus. The intravestibular schwannomas were limited to the vestibule, but growth into the bone next to the crista of the lateral semicircular canal was observed in 1 patient. Conclusions: Complete removal of an ILS may require partial removal of the modiolus or bone surrounding the crista ampullaris as an ILS may extend into these structures, risking damage of the neuronal structures. Due to the slow growth of the ILS, it remains unclear if a complete resection is required with the risk of destroying neural structures hindering hearing rehabilitation with a cochlear implant

MOLECULAR EPIDEMIOLOGY OF STENOTROPHOMONAS MALTOPHILIA IN UNIVERSITY HOSPITAL

The aim of this investigation was to study the molecular epidemiology of Stenotrophomonas maltophilia in a university hospital in Italy. Sixty-one clinical isolates were collected from 43 patients during a two-year period. The majority of specimens were from the respiratory tract (41 of 43) of patients in the adult intensive care unit (ICU) (19 of 43) or cystic fibrosis (CF) patients (13 of 43). Genotypic analysis by pulsedfield gel electrophoresis (PFGE) of clinical isolates identified 31 different PFGE patterns. Although most patients were infected or colonized by different S. maltophilia clones, clones with identical genotype were isolated in patients from ICU, where two separate outbreaks were identified. Antimicrobial susceptibility identified a multi-resistant phenotype in all S. maltophilia PFGE clones. The majority of PFGE clones identified (six of seven clones from patients in the ICU) were susceptible to fluoroquinolones. Mechanical ventilation was associated with S. maltophilia acquisition in the ICU

Functional Imaging to Guide Network-Based TMS Treatments: Toward a Tailored Medicine Approach in Alzheimer’s Disease

A growing number of studies is using fMRI-based connectivity to guide transcranial magnetic stimulation (TMS) target identification in both normal and clinical populations. TMS has gained increasing attention as a potential therapeutic strategy also in Alzheimer’s disease (AD), but an endorsed target localization strategy in this population is still lacking. In this proof of concept study, we prove the feasibility of a tailored TMS targeting approach for AD, which stems from a network-based perspective. Based on functional imaging, the procedure allows to extract individual optimal targets meanwhile accounting for functional variability. Single-subject resting-state fMRI was used to extract individual target coordinates of two networks primarily affected in AD, the default mode and the fronto-parietal network. The localization of these targets was compared to that of traditional group-level approaches and tested against varying degrees of TMS focality. The distance between individual fMRI-derived coordinates and traditionally defined targets was significant for a supposed TMS focality of 12 mm and in some cases up to 20 mm. Comparison with anatomical labels confirmed a lack of 1:1 correspondence between anatomical and functional targets. The proposed network-based fMRI-guided TMS approach, while accounting for inter-individual functional variability, allows to target core AD networks, and might thus represent a step toward tailored TMS interventions for AD