Genomic traits of Klebsiella oxytoca DSM 29614, an uncommon metal-nanoparticle producer strain isolated from acid mine drainages

Abstract Background: Klebsiella oxytoca DSM 29614 - isolated from acid mine drainages - grows anaerobically using Fe(III)- citrate as sole carbon and energy source, unlike other enterobacteria and K. oxytoca clinical isolates. The DSM 29614 strain is multi metal resistant and produces metal nanoparticles that are embedded in its very peculiar capsular exopolysaccharide. These metal nanoparticles were effective as antimicrobial and anticancer compounds, chemical catalysts and nano-fertilizers. Results: The DSM 29614 strain genome was sequenced and analysed by a combination of in silico procedures. Comparative genomics, performed between 85 K. oxytoca representatives and K. oxytoca DSM 29614, revealed that this bacterial group has an open pangenome, characterized by a very small core genome (1009 genes, about 2%), a high fraction of unique (43,808 genes, about 87%) and accessory genes (5559 genes, about 11%). Proteins belonging to COG categories “Carbohydrate transport and metabolism” (G), “Amino acid transport and metabolism” (E), “Coenzyme transport and metabolism” (H), “Inorganic ion transport and metabolism” (P), and “membrane biogenesis-related proteins” (M) are particularly abundant in the predicted proteome of DSM 29614 strain. The results of a protein functional enrichment analysis - based on a previous proteomic analysis – revealed metabolic optimization during Fe(III)- citrate anaerobic utilization. In this growth condition, the observed high levels of Fe(II) may be due to different flavin metal reductases and siderophores as inferred form genome analysis. The presence of genes responsible for the synthesis of exopolysaccharide and for the tolerance to heavy metals was highlighted too. The inferred genomic insights were confirmed by a set of phenotypic tests showing specific metabolic capability in terms of i) Fe2+ and exopolysaccharide production and ii) phosphatase activity involved in precipitation of metal ion-phosphate salts. Conclusion: The K. oxytoca DSM 29614 unique capabilities of using Fe(III)-citrate as sole carbon and energy source in anaerobiosis and tolerating diverse metals coincides with the presence at the genomic level of specific genes that can support i) energy metabolism optimization, ii) cell protection by the biosynthesis of a peculiar exopolysaccharide armour entrapping metal ions and iii) general and metal-specific detoxifying activities by different proteins and metabolites

External ventricular drainage alone versus endoscopic surgery for severe intraventricular hemorrhage: a comparative retrospective analysis on outcome and shunt dependency

none6Object Massive intraventricular hemorrhages (IVHs) require aggressive and rapid management to decrease intracranial hypertension, because the amount of intraventricular blood is a strong negative prognostic predictor on outcome. Neuroendoscopy may offer some advantages over more traditional surgical approaches on outcome and may decrease the number of shunt procedures that need to be performed. Methods The authors retrospectively reviewed the clinical and radiological data in 96 patients treated for massive IVH who were admitted between January 1996 and June 2008 to the neurosurgery unit after undergoing emergency CT scanning. Forty-eight patients (Group A) were treated with endoscopic aspiration surgery using a flexible endoscope with a “freehand” technique. A historical group of 48 patients (Group B) treated using external ventricular drain (EVD) placement alone was used as a comparison. The authors compared the radiological results with the clinical outcomes at 1 year according to the modified Rankin Scale and the need for internal CSF shunt treatment in the 2 groups. Results Endoscopic aspiration did not significantly affect the outcome at 1 year as determined using the modified Rankin Scale. Patients who underwent endoscopy had an EVD in place for 0.18 days fewer than patients treated with an EVD alone. Patients undergoing external ventricular drainage alone had a 5 times greater chance of requiring a shunting procedure than those treated using neuroendoscopy and external ventricular drainage. Neuroendoscopy plus external drainage reduces shunting rates by 34% when compared with external drainage alone. Conclusions The reduction in internal shunt surgery encourages the adoption of neuroendoscopic aspiration of severe IVH as a therapeutic tool to decrease shunt dependency.mixedLuca Basaldella;Elisabetta Marton;Alessandro Fiorindi;Bruno Scarpa;Hadi Badreddine;Pierluigi LongattiBasaldella, Luca; Marton, Elisabetta; Alessandro, Fiorindi; Scarpa, Bruno; Hadi, Badreddine; Longatti, Pierluig

Cognition and Behavior in Pre-Pubertal Children With Prader-Willi Syndrome and Associations With Sleep-Related Breathing Disorders

Prader-Willi syndrome (PWS) is characterized by hypotonia hypogonadism, obesity, and short stature. Neurobehavioral abnormalities, cognitive impairment, and sleep-related breathing disorders (SRBD) are common. In the general population associations between neurobehavioral and cognitive abnormalities and SRBD have been found. We investigated cognition, behavior, and SRBD in children with PWS. Thirty-one pre-pubertal PWS children were evaluated (5 with paternal deletion, 14 with maternal disomy, 4 with imprinting-center mutation, and in 8 the defect was not specified). Cognition was assessed by Wechler scale subtests, and behavior by parent-questionnaires. Polysomnography was performed. Cognition, behavior, and associations with SRBD were evaluated. All cognitive subtests were significantly below O SDS, with the lowest median (interquatile range) scores for the Block design subtest (-2.7 SDS(-3.0 to -0.3)). In 60%, verbal subsets were less affected than performance subtests. Parents reported problem behavior related to "emotions/behavior not adapted to the social situation" and "insensitivity to social information". All children had SRBD, with an Apnea Hypopnea Index of 4.1/hr (2.6-7.9). One performance subtest score was significantly higher in children with better sleep efficiency, and daytime sleepiness was associated with more autistic-like social impairment in contrast to our expectations, behaviors was worse in children with better sleep-related breathing. In pre-pubertal PWS children, cognitive is impaired. Neurobehavioral abnormalities are common, particularly autistic-like social impairment. Sleep efficiency was associated with better performance on one of the performance subtests, and neurobehavioral abnormalities were associated with daytime sleepiness. In contrast, we could not confirm a positive association of neurobehavioral abnormalities with SRBD in PWS. (C) 2008 Wiley-Liss, Inc