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271.
Rashmi?KumariyaEmail author Shiv?Kumar?Sood Yudhishthir?Singh?Rajput Anita?Kumari?Garsa 《Annals of microbiology》2015,65(2):721-732
Due to innate and acquired resistance in Enterococcus faecalis against most antibiotics, identification of new alternatives has increased interest in diverse populations of potent cationic antimicrobial peptides (CAMPs) for treatment and natural food biopreservation. The CAMPs, after crossing the cell wall to the periplasmic space, kill their target strain by forming pores in the cell membrane. However, reports of resistance against these CAMPs necessitated the understanding of step(s) interfered with while acquiring this resistance, for designing effective CAMP analogs. In this direction, we selected stable and gradual dose-dependent pediocin PA-1 single exposure resistant (Pedr) mutants of E. faecalis, which conferred cross-protection to diverse CAMPs, viz., HNP-1, nisin and alamethicin but not to polymyxin B, lysozyme and vancomycin. With these Pedr mutants of E. faecalis there was: a gradual neutralization in cell wall surface charge involving D-alanylation of wall teichoic acids (WTA) and lipoteichoic acids (LTA), increase in cell-surface hydrophobicity, increased cell aggregation and biofilm formation and ultra-structural changes in the cell wall, and a reduction of periplasmic space. In addition, a gradual decrease in expression of mannose PTS two (mpt) operon was also observed with distinct changes in growth rate achieving the same biomass production during the stationary phase. These results show that resistance to these CAMPs is not due to mpt directly acting as a docking molecule but due to changes in the cell wall, which increased the permeability barrier to CAMPs diffusion to reach the periplasmic space. 相似文献
272.
Caroline Jézéquel Fabrice Lainé Bruno Laviolle Anita Kiani Edouard Bardou-Jacquet Yves Deugnier 《PloS one》2015,10(6)
Background & Aims
Hepatic iron is increased in dysmetabolic iron overload syndrome (DIOS). Whether this reflects elevated body iron stores is still debated. The study was aimed at assessing body iron stores in DIOS patients by calculating the amount of mobilized iron (AMI).Methods
We conducted a prospective case-control study comparing AMI in 12 DIOS patients and 12 overweight normoferritinemic subjects matched on BMI and age. All participants were phlebotomized until serum ferritin dropped ≤ 50μg/L.Results
The two groups were comparable with respect to metabolic abnormalities and differed according to serum ferritin levels only. AMI was significantly (p<0.0001) higher in DIOS (2.5g±0.7) than in controls (0.8g±0.3). No side effects were related to phlebotomies. 相似文献273.
Samaneh Ghazanfari Anita Driessen-Mol Gustav J. Strijkers Frank P. T. Baaijens Carlijn V. C. Bouten 《PloS one》2015,10(5)
The collagen architecture is the major determinant of the function and mechanical behavior of cardiovascular tissues. In order to engineer a functional and load-bearing cardiovascular tissue with a structure that mimics the native tissue to meet in vivo mechanical demands, a complete understanding of the collagen orientation mechanism is required. Several methods have been used to visualize collagen architecture in tissue-engineered (TE) constructs, but they either have a limited imaging depth or have a complicated set up. In this study, Diffusion Tensor Imaging (DTI) is explored as a fast and reliable method to visualize collagen arrangement, and Confocal Laser Scanning Microscopy (CLSM) was used as a validation technique. Uniaxially constrained TE strips were cultured for 2 days, 10 days, 3 and 6 weeks to investigate the evolution of the collagen orientation with time. Moreover, a comparison of the collagen orientation in high and low aspect ratio (length/width) TE constructs was made with both methods. Both methods showed similar fiber orientation in TE constructs. Collagen fibers in the high aspect ratio samples were mostly aligned in the constrained direction, while the collagen fibers in low aspect ratio strips were mainly oriented in the oblique direction. The orientation changed to the oblique direction by extending culture time and could also be visualized. DTI captured the collagen orientation differences between low and high aspect ratio samples and with time. Therefore, it can be used as a fast, non-destructive and reliable tool to study the evolution of the collagen orientation in TE constructs. 相似文献
274.
Erin M. Kollitz Guozhu Zhang Mary Beth Hawkins G. Kerr Whitfield David M. Reif Seth W. Kullman 《PloS one》2015,10(4)
The vertebrate genome is a result of two rapid and successive rounds of whole genome duplication, referred to as 1R and 2R. Furthermore, teleost fish have undergone a third whole genome duplication (3R) specific to their lineage, resulting in the retention of multiple gene paralogs. The more recent 3R event in teleosts provides a unique opportunity to gain insight into how genes evolve through specific evolutionary processes. In this study we compare molecular activities of vitamin D receptors (VDR) from basal species that diverged at key points in vertebrate evolution in order to infer derived and ancestral VDR functions of teleost paralogs. Species include the sea lamprey (Petromyzon marinus), a 1R jawless fish; the little skate (Leucoraja erinacea), a cartilaginous fish that diverged after the 2R event; and the Senegal bichir (Polypterus senegalus), a primitive 2R ray-finned fish. Saturation binding assays and gel mobility shift assays demonstrate high affinity ligand binding and classic DNA binding characteristics of VDR has been conserved across vertebrate evolution. Concentration response curves in transient transfection assays reveal EC50 values in the low nanomolar range, however maximum transactivational efficacy varies significantly between receptor orthologs. Protein-protein interactions were investigated using co-transfection, mammalian 2-hybrid assays, and mutations of coregulator activation domains. We then combined these results with our previous study of VDR paralogs from 3R teleosts into a bioinformatics analysis. Our results suggest that 1, 25D3 acts as a partial agonist in basal species. Furthermore, our bioinformatics analysis suggests that functional differences between VDR orthologs and paralogs are influenced by differential protein interactions with essential coregulator proteins. We speculate that we may be observing a change in the pharmacodynamics relationship between VDR and 1, 25D3 throughout vertebrate evolution that may have been driven by changes in protein-protein interactions between VDR and essential coregulators. 相似文献
275.
Martijn L. Vandegehuchte Ursina Raschein Martin Schütz Dariusz J. Gwiazdowicz Anita C. Risch 《PloS one》2015,10(3)
Recognition is growing that besides ungulates, small vertebrate and invertebrate herbivores are important drivers of grassland functioning. Even though soil microarthropods play key roles in several soil processes, effects of herbivores—especially those of smaller body size—on their communities are not well understood. Therefore, we progressively excluded large, medium and small vertebrate and invertebrate herbivores for three growing seasons using size-selective fences in two vegetation types in subalpine grasslands; short-grass and tall-grass vegetation generated by high and low historical levels of ungulate grazing. Herbivore exclusions generally had few effects on microarthropod communities, but exclusion of all herbivore groups resulted in decreased total springtail and Poduromorpha richness compared with exclusion of only ungulates and medium-sized mammals, regardless of vegetation type. The tall-grass vegetation had a higher total springtail richness and mesostigmatid mite abundance than the short-grass vegetation and a different oribatid mite community composition. Although several biotic and abiotic variables differed between the exclusion treatments and vegetation types, effects on soil microarthropods were best explained by differences in nutrient and fibre content of the previous year’s vegetation, a proxy for litter quality, and to a lesser extent soil temperature. After three growing seasons, smaller herbivores had a stronger impact on these functionally important soil microarthropod communities than large herbivores. Over longer time-scales, however, large grazers created two different vegetation types and thereby influenced microarthropod communities bottom-up, e.g. by altering resource quality. Hence, both short- and long-term consequences of herbivory affected the structure of the soil microarthropod community. 相似文献
276.
Marsh K?nigs Wouter D. Weeda L. W. Ernest van Heurn R. Jeroen Vermeulen J. Carel Goslings Jan S. K. Luitse Bwee Tien Poll-Thé Anita Beelen Marleen van der Wees Rachèl J. J. K. Kemps Coriene E. Catsman-Berrevoets Jaap Oosterlaan 《PloS one》2015,10(12)
Background
Axonal injury after traumatic brain injury (TBI) may cause impaired sensory integration. We aim to determine the effects of childhood TBI on visual integration in relation to general neurocognitive functioning.Methods
We compared children aged 6–13 diagnosed with TBI (n = 103; M = 1.7 years post-injury) to children with traumatic control (TC) injury (n = 44). Three TBI severity groups were distinguished: mild TBI without risk factors for complicated TBI (mildRF- TBI, n = 22), mild TBI with ≥1 risk factor (mildRF+ TBI, n = 46) or moderate/severe TBI (n = 35). An experimental paradigm measured speed and accuracy of goal-directed behavior depending on: (1) visual identification; (2) visual localization; or (3) both, measuring visual integration. Group-differences on reaction time (RT) or accuracy were tracked down to task strategy, visual processing efficiency and extra-decisional processes (e.g. response execution) using diffusion model analysis. General neurocognitive functioning was measured by a Wechsler Intelligence Scale short form.Results
The TBI group had poorer accuracy of visual identification and visual integration than the TC group (Ps ≤ .03; ds ≤ -0.40). Analyses differentiating TBI severity revealed that visual identification accuracy was impaired in the moderate/severe TBI group (P = .05, d = -0.50) and that visual integration accuracy was impaired in the mildRF+ TBI group and moderate/severe TBI group (Ps < .02, ds ≤ -0.56). Diffusion model analyses tracked impaired visual integration accuracy down to lower visual integration efficiency in the mildRF+ TBI group and moderate/severe TBI group (Ps < .001, ds ≤ -0.73). Importantly, intelligence impairments observed in the TBI group (P = .009, d = -0.48) were statistically explained by visual integration efficiency (P = .002).Conclusions
Children with mildRF+ TBI or moderate/severe TBI have impaired visual integration efficiency, which may contribute to poorer general neurocognitive functioning. 相似文献277.
Michael S. Donnenberg Tracy H. Hazen Tamer H. Farag Sandra Panchalingam Martin Antonio Anowar Hossain Inacio Mandomando John Benjamin Ochieng Thandavarayan Ramamurthy Boubou Tamboura Anita Zaidi Myron M. Levine Karen Kotloff David A. Rasko James P. Nataro 《PLoS neglected tropical diseases》2015,9(5)
Background
Typical enteropathogenic Escherichia coli (tEPEC) strains were associated with mortality in the Global Enteric Multicenter Study (GEMS). Genetic differences in tEPEC strains could underlie some of the variability in clinical outcome.Methods
We produced draft genome sequences of all available tEPEC strains from GEMS lethal infections (LIs) and of closely matched EPEC strains from GEMS subjects with non-lethal symptomatic infections (NSIs) and asymptomatic infections (AIs) to identify gene clusters (potential protein encoding sequences sharing ≥90% nucleotide sequence identity) associated with lethality.Results
Among 14,412 gene clusters identified, the presence or absence of 392 was associated with clinical outcome. As expected, more gene clusters were associated with LI versus AI than LI versus NSI. The gene clusters more prevalent in strains from LI than those from NSI and AI included those encoding proteins involved in O-antigen biogenesis, while clusters encoding type 3 secretion effectors EspJ and OspB were among those more prevalent in strains from non-lethal infections. One gene cluster encoding a variant of an NleG ubiquitin ligase was associated with LI versus AI, while two other nleG clusters had the opposite association. Similar associations were found for two nleG gene clusters in an additional, larger sample of NSI and AI GEMS strains.Conclusions
Particular genes are associated with lethal tEPEC infections. Further study of these factors holds potential to unravel the mechanisms underlying severe disease and to prevent adverse outcomes. 相似文献278.
Laxmi Silwal-Pandit Hege Russnes Elin Borgen Veronica Skarpeteig Hans Kristian Moen Vollan Ellen Schlichting Rolf K?resen Bj?rn Naume Anne-Lise B?rresen-Dale Marianne Farnebo Anita Langer?d 《PloS one》2015,10(10)
WRAP53 protein controls intracellular trafficking of DNA repair proteins, the telomerase enzyme, and splicing factors. Functional loss of the protein has been linked to carcinogenesis, premature aging and neurodegeneration. The aim of this study was to investigate the prognostic significance of WRAP53 protein expression in breast cancer. A tissue microarray was constructed from primary breast tumors and immunostained by a polyclonal WRAP53 antibody to assess the protein expression pattern. Two different patient cohorts with long term follow-up were studied; a test- and a validation set of 154 and 668 breast tumor samples respectively. Breast cancer patients with tumor cells lacking the expression of WRAP53 in the nucleus had a significantly poorer outcome compared to patients with tumor cells expressing this protein in the nuclei (HR = 1.95, 95%CI = 1.09–3.51, p = 0.025). Nuclear localization of WRAP53 was further shown to be an independent marker of prognosis in multivariate analysis (HR = 2.57, 95%CI = 1.27–5.19, p = 0.008), and also significantly associated with better outcome in patients with TP53 mutation. Here we show that the sub-cellular localization of the WRAP53 protein has a significant impact on breast cancer survival, and thus has a potential as a clinical marker in diagnostics and treatment. 相似文献
279.
280.
Anita Kloss-Brandst?tter Hansi Weissensteiner Gertraud Erhart Georg Sch?fer Lukas Forer Sebastian Sch?nherr Dominic Pacher Christof Seifarth Andrea St?ckl Liane Fendt Irma Sottsas Helmut Klocker Christian W. Huck Michael Rasse Florian Kronenberg Frank R. Kloss 《PloS one》2015,10(8)