Physiological aggregation of maltodextrin phosphorylase from Pyrococcus furiosus and its application in a process of batch starch degradation to α-d-glucose-1-phosphate

Maltodextrin phosphorylase from Pyrococcus furiosus (PF1535) was fused with the cellulose-binding domain of Clostridium cellulovorans serving as an aggregation module. After molecular cloning of the corresponding gene fusion construct and controlled expression in Escherichia coli BL21, 83% of total maltodextrin phosphorylase activity (0.24 U/mg of dry cell weight) was displayed in active inclusion bodies. These active inclusion bodies were easily isolated by nonionic detergent treatment and directly used for maltodextrin conversion to α-d-glucose-1-phosphate in a repetitive batch mode. Only 10% of enzyme activity was lost after ten conversion cycles at optimum conditions.     

Development of a pattern in biochemical parameters in the core and penumbra during infarct evolution after transient MCAO in rats

The period from stroke initiation to the cessation of penumbra damage spread represents a therapeutic window when expansion can be alleviated. In the present work, we studied some biochemical parameters helpful for the estimation of infarct progression and thus for the application of interventions.     

Terrestrial slugs (Gastropoda, Pulmonata) in the NATURA 2000 areas of Cyprus island

Terrestrial slugs of the Island of Cyprus were recently studied in the framework of a study of the whole terrestrial malacofauna of the island. The present work was carried out in the Natura 2000 conservation areas of the island in 155 sampling sites over three years (2004-2007). Museum collections as well as literature references were included. In total six species are present in the Natura 2000 areas of the island, belonging to three families: Limacidae, Agriolimacidae and Milacidae. One of the species, Milax riedeli, is a new record for the island. The distribution of the species across the island and in the surrounding areas is discussed.     

Actin-binding domain of mouse plectin. Crystal structure and binding to vimentin.

Plectin, a large and widely expressed cytolinker protein, is composed of several subdomains that harbor binding sites for a variety of different interaction partners. A canonical actin-binding domain (ABD) comprising two calponin homology domains (CH1 and CH2) is located in proximity to its amino terminus. However, the ABD of plectin is unique among actin-binding proteins as it is expressed in the form of distinct, plectin isoform-specific versions. We have determined the three-dimensional structure of two distinct crystalline forms of one of its ABD versions (pleABD/2alpha) from mouse, to a resolution of 1.95 and 2.0 A. Comparison of pleABD/2alpha with the ABDs of fimbrin and utrophin revealed structural similarity between plectin and fimbrin, although the proteins share only low sequence identity. In fact, pleABD/2alpha has been found to have the same compact fold as the human plectin ABD and the fimbrin ABD, differing from the open conformation described for the ABDs of utrophin and dystrophin. Plectin harbors a specific binding site for intermediate filaments of various types within its carboxy-terminal R5 repeat domain. Our experiments revealed an additional vimentin-binding site of plectin, residing within the CH1 subdomain of its ABD. We show that vimentin binds to this site via the amino-terminal part of its rod domain. This additional amino-terminal intermediate filament protein binding site of plectin may have a function in intermediate filament dynamics and assembly, rather than in linking and stabilizing intermediate filament networks.     

Bacterial aerosols in an urban nursery school in Gliwice,Poland: a case study

This work presents the results of the study of airborne bacteria in a kindergarten in Gliwice, Upper Silesia, Poland. In this study, the samples of bioaerosols were collected using six-stage Andersen cascade impactor (with aerodynamic cutoff diameters 7.0, 4.7, 3.3, 2.1, 1.1, and 0.65 μm). The level of culturable bacterial aerosols indoors was about 3000 CFU m^?3—six to eight times higher than outdoors. In the classrooms, respirable bacterial particles, <4.7 µm, contributed up to 85 % of the total number of culturable bacteria, increasing the possible adverse health effects due to their inhalation. The identification of the bacterial species showing the dominance of gram-positive cocci in the indoor environment and non-sporing gram-positive rods in the outdoor air indicates that most of the bacteria present in the studied kindergarten are human origin. Using the obtained data, the nursery school exposure dose (NSED) of bioaerosols was estimated for the children and personnel of this kindergarten (nursery school). The highest value of NSED was obtained for younger children (930 CFU kg^?1) compared to older children (about 600 CFU kg^?1) and to the kindergarten staff (about 300 CFU kg^?1). This result suggests the elevated risk of adverse health effects in younger children exposed to the bioaerosols in the kindergarten, including infections.     

Structure of hemocyanin subunit CaeSS2 of the crustacean Mediterranean crab Carcinus aestuarii

Arthropodan hemocyanins are giant respiratory proteins responsible for oxygen transport. They exhibit unusual assemblies of up to 48 structural subunits. Hemocyanin from Carcinus aestuarii contains three major and two minor structural subunits. Here, we reveal the primary structure of the gamma-type 75 kDa subunit of Carcinus aestuarii hemocyanin, CaeSS2, and combine structure-based sequence alignments, tryptophan fluorescence, and glycosylation analyses to provide insights into the structural and functional organisation of CaeSS2. We identify three functional domains and three conserved histidine residues that most likely participate in the formation of the copper active site in domain 2. Oxygen-binding ability of Carcinus aestuarii Hc and its structural subunit 2 was studied using CD and fluorescence spectroscopy. Removing the copper dioxygen system from the active site led to a decrease of the melting temperature, which can be explained by a stabilizing effect of the binding metal ion. To study the quenching effect of the active site copper ions in hemocyanins, the copper complex Cu(II)(PuPhPy)2+ was used, which appears as a very strong quencher of the tryptophan emission. Furthermore, the structural localization was clarified and found to explain the observed fluorescence behavior of the protein. Sugar analysis reveals that CaeSS2 is glycosylated, and oligosaccharide chains connected to three O-glycosylated and one N-glycosylated sites were found.     

Children who acquire HIV infection perinatally are at higher risk of early death than those acquiring infection through breastmilk: a meta-analysis

BACKGROUND: Assumptions about survival of HIV-infected children in Africa without antiretroviral therapy need to be updated to inform ongoing UNAIDS modelling of paediatric HIV epidemics among children. Improved estimates of infant survival by timing of HIV-infection (perinatally or postnatally) are thus needed. METHODOLOGY/PRINCIPAL FINDINGS: A pooled analysis was conducted of individual data of all available intervention cohorts and randomized trials on prevention of HIV mother-to-child transmission in Africa. Studies were right-censored at the time of infant antiretroviral initiation. Overall mortality rate per 1000 child-years of follow-up was calculated by selected maternal and infant characteristics. The Kaplan-Meier method was used to estimate survival curves by child's HIV infection status and timing of HIV infection. Individual data from 12 studies were pooled, with 12,112 children of HIV-infected women. Mortality rates per 1,000 child-years follow-up were 39.3 and 381.6 for HIV-uninfected and infected children respectively. One year after acquisition of HIV infection, an estimated 26% postnatally and 52% perinatally infected children would have died; and 4% uninfected children by age 1 year. Mortality was independently associated with maternal death (adjusted hazard ratio 2.2, 95%CI 1.6-3.0), maternal CD4<350 cells/ml (1.4, 1.1-1.7), postnatal (3.1, 2.1-4.1) or peri-partum HIV-infection (12.4, 10.1-15.3). CONCLUSIONS/RESULTS: These results update previous work and inform future UNAIDS modelling by providing survival estimates for HIV-infected untreated African children by timing of infection. We highlight the urgent need for the prevention of peri-partum and postnatal transmission and timely assessment of HIV infection in infants to initiate antiretroviral care and support for HIV-infected children.     

A useful relationship between epidemiology and queueing theory: The distribution of the number of infectives at the moment of the first detection

In this paper we establish a relation between the spread of infectious diseases and the dynamics of so called M/G/1 queues with processor sharing. The relation between the spread of epidemics and branching processes, which is well known in epidemiology, and the relation between M/G/1 queues and birth death processes, which is well known in queueing theory, will be combined to provide a framework in which results from queueing theory can be used in epidemiology and vice versa.In particular, we consider the number of infectious individuals in a standard SIR epidemic model at the moment of the first detection of the epidemic, where infectious individuals are detected at a constant per capita rate. We use a result from the literature on queueing processes to show that this number of infectious individuals is geometrically distributed.     

Interaction of nucleoredoxin with protein phosphatase 2A

A trimeric protein phosphatase 2A (PP2A(T55)) composed of the catalytic (PP2Ac), structural (PR65/A), and regulatory (PR55/B) subunits was isolated from rabbit skeletal muscle by thiophosphorylase affinity chromatography, and contained two additional proteins of 54 and 55 kDa, respectively. The 54 kDa protein was identified as eukaryotic translation termination factor 1 (eRF1) and as a PP2A interacting protein. The 55 kDa protein is now identified as nucleoredoxin (NRX). The formation of a complex between GST-NRX, PP2A(C) and PP2A(D) was demonstrated by pull-down experiments with purified forms of PP2A, and by immunoprecipitation of HA-tagged NRX expressed in HEK293 cells complexed endogenous PP2A subunits. Analysis of PP2A activity in the presence of GST-NRX showed that NRX competed with polycations for both stimulatory and inhibitory effects on different forms of PP2A.