Randomized,Double-Blind,Placebo-Controlled Study on Decolonization Procedures for Methicillin-Resistant Staphylococcus aureus (MRSA) among HIV-Infected Adults

BackgroundHIV-infected persons have increased risk of MRSA colonization and skin and soft-tissue infections (SSTI). However, no large clinical trial has examined the utility of decolonization procedures in reducing MRSA colonization or infection among community-dwelling HIV-infected persons.Methods550 HIV-infected adults at four geographically diverse US military HIV clinics were prospectively screened for MRSA colonization at five body locations every 6 months during a 2-year period. Those colonized were randomized in a double-blind fashion to nasal mupirocin (Bactroban) twice daily and hexachlorophene (pHisoHex) soaps daily for 7 days compared to placeboes similar in appearance but without specific antibacterial activity. The primary endpoint was MRSA colonization at 6-months post-randomization; secondary endpoints were time to MRSA clearance, subsequent MRSA infections/SSTI, and predictors for MRSA clearance at the 6-month time point.ResultsForty-nine (9%) HIV-infected persons were MRSA colonized and randomized. Among those with 6-month colonization data (80% of those randomized), 67% were negative for MRSA colonization in both groups (p = 1.0). Analyses accounting for missing 6-month data showed no significant differences could have been achieved. In the multivariate adjusted models, randomization group was not associated with 6-month MRSA clearance. The median time to MRSA clearance was similar in the treatment vs. placebo groups (1.4 vs. 1.8 months, p = 0.35). There was no difference on subsequent development of MRSA infections/SSTI (p = 0.89). In a multivariable model, treatment group, demographics, and HIV-specific factors were not predictive of MRSA clearance at the 6-month time point.ConclusionA one-week decolonization procedure had no effect on MRSA colonization at the 6-month time point or subsequent infection rates among community-dwelling HIV-infected persons. More aggressive or novel interventions may be needed to reduce the burden of MRSA in this population.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00631566","term_id":"NCT00631566"}}NCT00631566     

Coexistence of two Cyclotella diatom species in the plankton of Lake Baikal

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The removal of stickies with modified starch and chitosan-Highly cationic and hydrophobic types compared with unmodified ones

The removal of dissolved and colloidal substances (DCS) in paper cycling water, so called stickies, with tailored natural polymers, having cationic as well as hydrophobic groups, was investigated using model suspensions made by the recycling of paper. The sticky content, characterized by the turbidity, the anionic charge, and the total organic carbon content (TOC) was increased by the addition of latex. The dynamic surface tension was established as useful tool for the characterization of the sticky content. The sticky removal using the starch derivatives (with benzyl- as well as ethyl-substituents), from very low up to high cationic charge and N-(benzyl)chitosan was compared. Depending on the properties of the derivatives two possible mechanisms can be found: "charge dominated removal" or "removal dominated by hydrophobicity." It seems that turbidity and TOC are lowered especially due to charge interaction whereas the increase of the surface tension is mainly caused by the hydrophobic character of the modified natural polymers.     

East Weddell Sea echinoids from the JR275 expedition

Information regarding the echinoids in this dataset is based on the Agassiz Trawl (AGT) and epibenthic sledge (EBS) samples collected during the British Antarctic Survey cruise JR275 on the RRS James Clark Ross in the austral summer 2012. A total of 56 (1 at the South Orkneys and 55 in the Eastern Weddell Sea) Agassiz Trawl and 18 (2 at the South Orkneys and 16 in the Eastern Weddell Sea) epibenthic sledge deployments were performed at depths ranging from ~280 to ~2060 m. This presents a unique collection for the Antarctic benthic biodiversity assessment of an important group of benthic invertebrates. In total 487 specimens belonging to six families, 15 genera, and 22 morphospecies were collected. The species richness per station varied between one and six. Total species richness represents 27% of the 82 echinoid species ever recorded in the Southern Ocean (David et al. 2005b, Pierrat et al. 2012, Saucède et al. 2014). The Cidaridae (sub-family Ctenocidarinae) and Schizasteridae are the two most speciose families in the dataset. They comprise seven and nine species respectively. This is illustrative of the overall pattern of echinoid diversity in the Southern Ocean where 65% of Antarctic species belong to the families Schizasteridae and Cidaridae (Pierrat et al. 2012).     

Molecular mechanism of 14-3-3 protein-mediated inhibition of plant nitrate reductase

14-3-3 proteins regulate key processes in eukaryotic cells including nitrogen assimilation in plants by tuning the activity of nitrate reductase (NR), the first and rate-limiting enzyme in this pathway. The homodimeric NR harbors three cofactors, each of which is bound to separate domains, thus forming an electron transfer chain. 14-3-3 proteins inhibit NR by binding to a conserved phosphorylation site localized in the linker between the heme and molybdenum cofactor-containing domains. Here, we have investigated the molecular mechanism of 14-3-3-mediated NR inhibition using a fragment of the enzyme lacking the third domain, allowing us to analyze electron transfer from the heme cofactor via the molybdenum center to nitrate. The kinetic behavior of the inhibited Mo-heme fragment indicates that the principal point at which 14-3-3 acts is the electron transfer from the heme to the molybdenum cofactor. We demonstrate that this is not due to a perturbation of the reduction potentials of either the heme or the molybdenum center and conclude that 14-3-3 most likely inhibits nitrate reductase by inducing a conformational change that significantly increases the distance between the two redox-active sites.     

Hermit crabs and their symbionts: Reactions to artificially induced anoxia on a sublittoral sediment bottom

Hermit crabs play an important role in the Northern Adriatic Sea due to their abundance, wide range of symbionts, and function in structuring the benthic community. Small-scale (0.25?m(2)) hypoxia and anoxia were experimentally generated on a sublittoral soft bottom in 24?m depth in the Gulf of Trieste. This approach successfully simulates the seasonal low dissolved oxygen (DO) events here and enabled studying the behaviour and mortality of the hermit crab Paguristes eremita. The crabs exhibited a sequence of predictable stress responses and ultimately mortality, which was correlated with five oxygen thresholds. Among the crustaceans, which are a sensitive group to oxygen depletion, P. eremita is relatively tolerant. Initially, at mild hypoxia (2.0 to 1.0?ml?l(-?1) DO), hermit crabs showed avoidance by moving onto better oxygenated, elevated substrata. This was accompanied by a series of responses including decreased locomotory activity, increased body movements and extension from the shell. During a moribund phase at severe hypoxia (0.5 to 0.01?ml?l(-?1) DO), crabs were mostly immobile in overturned shells and body movements decreased. Anoxia triggered emergence from the shell, with a brief locomotion spurt of shell-less crabs. The activity pattern of normally day-active crabs was altered during hypoxia and anoxia. Atypical interspecific interactions occurred: the crab Pisidia longimana increasingly aggregated on hermit crab shells, and a hermit crab used the emerged infaunal sea urchin Schizaster canaliferus as an elevated substrate. Response patterns varied somewhat according to shell size or symbiont type (the sponge Suberites domuncula). Mortality occurred after extended anoxia (~?1.5?d) and increased hydrogen sulphide levels (H(2)S ~?128?μmol). The relative tolerance of crabs and certain symbionts (e.g. the sea anemone Calliactis parasitica) - as potential survivors and recolonizers of affected areas - may influence and promote community recovery after oxygen crises.     

A new fast method for nanoLC-MALDI-TOF/TOF-MS analysis using monolithic columns for peptide preconcentration and separation in proteomic studies

A new fast method for identification and characterization of proteolytic digests of proteins by monolithic liquid chromatography coupled with mass spectrometry has been developed. The advantages of the monolithic columns are a high-pressure stability and low back pressure resulting in higher flow rates for capillary or nanosize columns simplifying the system handling. As was shown in several publications, such monolithic stationary phases are highly qualified for the analysis of peptides and proteins, but so far, only small volumes could be injected into the system, which might hamper the sample preparation leading to protein precipitation and partial loss of sample. To overcome the problem of small injection volumes, we established a system including a short monolithic trap column to allow preconcentration of the peptides. The injected sample is flushed at higher flow rates onto the trap column, bound to the stationary phase, and in this way concentrated in a few nanoliters before starting the separation. The expanded system was optimized and tested using different reference protein samples. Eluting peptides were detected by MALDI-TOF/TOF-MS and identified by database searching. The system is now a permanent part for proteome analysis in our lab, and as such, it was successfully applied for the detection of post-translational modifications and the analysis of membrane proteins. One example for these analyses is also included in this paper.     

Efficient identification of near‐native conformations in ab initio protein structure prediction using structural profiles

One of the major bottlenecks in many ab initio protein structure prediction methods is currently the selection of a small number of candidate structures for high‐resolution refinement from large sets of low‐resolution decoys. This step often includes a scoring by low‐resolution energy functions and a clustering of conformations by their pairwise root mean square deviations (RMSDs). As an efficient selection is crucial to reduce the overall computational cost of the predictions, any improvement in this direction can increase the overall performance of the predictions and the range of protein structures that can be predicted. We show here that the use of structural profiles, which can be predicted with good accuracy from the amino acid sequences of proteins, provides an efficient means to identify good candidate structures. Proteins 2010. © 2009 Wiley‐Liss, Inc.     

In vitro reconstitution of fibrillar collagen type I assemblies at reactive polymer surfaces

The reconstitution of fibrillar collagen and its assemblies with heparin and hyaluronic acid was studied in vitro. Fibril formation kinetics were analyzed by turbidity and depletion measurements in solutions containing varied concentrations of collagen and glycosaminoglycans. Fibril-forming collagen solutions were further applied for the coating of planar substrates which had been modified with alternating maleic anhydride copolymer films before. The immobilized collagen assemblies were characterized with respect to the deposited amount of protein using ellipsometry and acidic hydrolysis/HPLC-based amino acid analysis, respectively. AFM, SEM, and cLSM were utilized to gain information on structural features and patterns formed by surface-attached fibrils depending on the initial solution concentrations of collagen. The results revealed that the addition of heparin and hyaluronic acid affected both the fibril dimensions and the meshwork characteristics of the surface-bound fibrils.