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Objectives: Swab-based nasal screening is commonly used to identify asymptomatic carriage of Staphylococcus aureus in patients. Bacterial detection depends on the uptake and release capacities of the swabs and on the swabbing technique itself. This study investigates the performance of different swab-types in nasal MRSA-screening by utilizing a unique artificial nose model to provide realistic and standardized screening conditions. Methods: An anatomically correct artificial nose model was inoculated with a numerically defined mixture of MRSA and Staphylococcus epidermidis bacteria at quantities of 4×102 and 8×102 colony forming units (CFU), respectively. Five swab-types were tested following a strict protocol. Bacterial recovery was measured for direct plating and after elution into Amies medium by standard viable count techniques. Results: Mean recovered bacteria quantities varied between 209 and 0 CFU for MRSA, and 365 and 0 CFU for S. epidermidis, resulting swab-type-dependent MRSA-screening-sensitivities ranged between 0 and 100%. Swabs with nylon flocked tips or cellular foam tips performed significantly better compared to conventional rayon swabs referring to the recovered bacterial yield (p<0.001). Best results were obtained by using a flocked swab in combination with Amies preservation medium. Within the range of the utilized bacterial concentrations, recovery ratios for the particular swab-types were independent of the bacterial species. Conclusions: This study combines a realistic model of a human nose with standardized laboratory conditions to analyze swab-performance in MRSA-screening situations. Therefore, influences by inter-individual anatomical differences as well as diverse colonization densities in patients could be excluded. Recovery rates vary significantly between different swab-types. The choice of the swab has a great impact on the laboratory result. In fact, the swab-type contributes significantly to true positive or false negative detection of nasal MRSA carriage. These findings should be considered when screening a patient. [ABSTRACT FROM AUTHOR]

Exposure to long-duration microgravity leads to ocular changes in astronauts, manifested by a variety of signs and symptoms during spaceflight that in some cases persist after return to Earth. These morphological and functional changes are only partly understood and are of occupational health relevance. To investigate further into the molecular basis of the changes occurring in ocular tissue upon exposure to spaceflight, eyes were collected from male C57BL/6 mice flown on STS-135 (FLT) on landing day or from their ground control counterparts maintained at similar conditions within the Animal Enclosure Module (AEM). One eye was fixed for histological sectioning while the contralateral eye was dissected to isolate the retina for gene expression profiling. 8-hydroxy-deoxyguanosine (8OHdG) staining showed a statistically significant increase in the inner nuclear layer of FLT samples compared to AEM. Gene expression analysis in isolated retina identified 139 differentially expressed genes in FLT compared to AEM control samples. The genes affected were mainly involved in pathways and processes of endoplasmic reticulum (ER) stress, inflammation, neuronal and glial cell loss, axonal degeneration, and herpes virus activation. These results suggest a concerted change in gene expression in the retina of mice flown in space, possibly leading to retinal damage, degeneration, and remodeling. [ABSTRACT FROM AUTHOR]

Objectives: Swabs are widely used to collect samples for microbiological analyses from various clinical settings. They vary by material, size, and structure of the tip. This study investigates the uptake and release capacities for liquid and bacteria. Methods: Five swabs were analyzed for their uptake and release capacities of Staphylococcus aureus and Staphylococcus epidermidis suspensions. Two approaches were investigated providing volume-restricted and unrestricted amounts of bacterial suspensions to mimic various clinical situations. Volume and bacterial uptake and release were measured in milligrams and by counting colony forming units (CFU), respectively. Results: Volume uptake and release in the unrestricted setting varied highly significant between 239.6 mg and 88.7 mg (p<0.001) and between 65.2 mg and 2.2 mg (p<0.001), respectively. In the volume-restricted setting the complete volume was absorbed by all swabs, volume release could only be detected for flocked swabs (2.7 mg; p<0.001). Highest amount of CFU release was detected for the MWE Dryswab in the unrestricted setting for both S. aureus and S. epidermidis with 1544 CFU and 553 CFU, respectively, lowest release for the Sarstedt neutral swab with 32 CFU and 17 CFU, respectively (p<0.001). In the volume-restricted setting MWE Σ-Swab released the highest bacterial amount with 135 CFU S. aureus and 55 CFU S. epidermidis, respectively, the lowest amount was released by Mast Mastaswab with 2 CFU S. aureus and 1 CFU S. epidermidis, respectively (p<0.001). Within the range of the utilized bacterial concentrations, uptake/release ratios were identical for the particular swab types and independent of the bacterial species. Conclusions: The influence of the swab type on subsequent diagnostic results is often underestimated. Uptake and release of the investigated bacteria vary significantly between different swab types and sampling conditions. For best diagnostic outcome swabs should be chosen according to the examined situation and the swab performance profile. [ABSTRACT FROM AUTHOR]

The growing demand to fulfill the needs of present-day medicine in terms of novel effective molecules has lead to reexamining some of the old and known bacterial secondary metabolites. Bacterial prodigiosins (prodiginines) have a long history of being re markable multipurpose compounds, best examined for their anticancer and antimalarial activities. Production of prodigiosin in the most common producer strain Serratia marcescens has been described in great detail. However, few reports have discussed the ecophysiological roles of these molecules in the producing strains, as well as their antibiotic and UV-protective properties. This review describes recent advances in the production process, biosynthesis, properties, and applications of bacterial prodigiosins. Special emphasis is put on undecylprodigiosin which has generally been a less studied member of the prodigiosin family. In addition, it has been suggested that proteins involved in undecylprodigiosin synthesis, RedG and RedH, could be a useful addition to the biocatalytic toolbox being able to mediate regio- and stereoselective oxidative cyclization. Judging by the number of recent references (216 for the 2007-2013 period), it has become clear that undecylprodigiosin and other bacterial prodigiosins still hold surprises in terms of valuable properties and applicative potential to medical and other industrial fields and that they still deserve continuing research curiosity. [ABSTRACT FROM AUTHOR]

The article discusses a study related to the anatomical distributions of solar ultraviolet radiation (UVR) on strawberry production workers. Topics include assessment of UVR hazard during agricultural production cycle, the research being carried out on the experimental farm of Universitéa Politenica delle Marche in Agugliano, Italy, and use of electronic dosimeters to record UVR exposure. It mentions the minimum value required to produce erythema in unacclimatized white skin.

Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings) poses a potential risk to jeopardize scientific exploration of other celestial bodies. This is particularly critical for spacecraft components intended for hard landing. So far, it remained unclear if polymers are indeed a source of microbial contamination. In addition, data with respect to survival of microbes during the embedding/polymerization process are sparse. In this study we developed testing strategies to quantitatively examine encapsulated bioburden in five different polymers used frequently and in large quantities on spaceflight hardware. As quantitative extraction of the bioburden from polymerized (solid) materials did not prove feasible, contaminants were extracted from uncured precursors. Cultivation-based analyses revealed <0.1–2.5 colony forming units (cfu) per cm3 polymer, whereas quantitative PCR-based detection of contaminants indicated considerably higher values, despite low DNA extraction efficiency. Results obtained from this approach reflect the most conservative proxy for encapsulated bioburden, as they give the maximum bioburden of the polymers irrespective of any additional physical and chemical stress occurring during polymerization. To address the latter issue, we deployed an embedding model to elucidate and monitor the physiological status of embedded Bacillus safensis spores in a cured polymer. Staining approaches using AlexaFluor succinimidyl ester 488 (AF488), propidium monoazide (PMA), CTC (5-cyano-2,3-diotolyl tetrazolium chloride) demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld 2216 B/A. Using the methods presented here, we were able to estimate the worst case contribution of encapsulated bioburden in different polymers to the bioburden of spacecraft. We demonstrated that spores were not affected by polymerization processes. Besides Planetary Protection considerations, our results could prove useful for the manufacturing of food packaging, pharmacy industry and implant technology. [ABSTRACT FROM AUTHOR]

We have proposed an experiment (the Tanpopo mission) to capture microbes on the Japan Experimental Module of the International Space Station. An ultra low-density silica aerogel will be exposed to space for more than 1 year. After retrieving the aerogel, particle tracks and particles found in it will be visualized by fluorescence microscopy after staining it with a DNA-specific fluorescence dye. In preparation for this study, we simulated particle trapping in an aerogel so that methods could be developed to visualize the particles and their tracks. During the Tanpopo mission, particles that have an orbital velocity of ~8 km/s are expected to collide with the aerogel. To simulate these collisions, we shot Deinococcus radiodurans-containing Lucentite particles into the aerogel from a two-stage light-gas gun (acceleration 4.2 km/s). The shapes of the captured particles, and their tracks and entrance holes were recorded with a microscope/camera system for further analysis. The size distribution of the captured particles was smaller than the original distribution, suggesting that the particles had fragmented. We were able to distinguish between microbial DNA and inorganic compounds after staining the aerogel with the DNA-specific fluorescence dye SYBR green I as the fluorescence of the stained DNA and the autofluorescence of the inorganic particles decay at different rates. The developed methods are suitable to determine if microbes exist at the International Space Station altitude. [ABSTRACT FROM AUTHOR]

The potential to commercialize nonthermal ultraviolet (UV) light technologies as new methods for preserving food products has caught the attention of a food industry that wishes to fulfill consumers' demands for fresh products. Numerous investigations have demonstrated UV light's ability to inactivate a wide range of microorganisms. However, the lack of UV sensitivity data from pathogenic and spoilage bacteria is evident. In addition, the main factors associated with UV light in terms of microbial lethality remain unclear. This review surveys critical factors (process, microbial, and environmental parameters) that determine UV microbial resistance and assess the effects of such factors on the inactivation mechanism and repair pathway efficiency. The effects of some of these factors, such as prior sublethal stresses and post-recovery conditions of UV treatments, may extensively improve the damage repair capacity and thus microbial survivability. Further research is needed to establish adequate control measures pre- and post-UV treatments. Furthermore, the possibility of combining UV light with conventional preservatives and other nonthermal technologies was assessed. The combination of UV light with mild heating or oxidant compounds could offer promising treatments to enhance the safety and stability of minimally processed foods. [ABSTRACT FROM AUTHOR]

Astronauts working and living in space are exposed to considerably higher doses and different qualities of ionizing radiation than people on Earth. The multilateral MATROSHKA (MTR) experiment, coordinated by the German Aerospace Center, represents the most comprehensive effort to date in radiation protection dosimetry in space using an anthropomorphic upper-torso phantom used for radiotherapy treatment planning. The anthropomorphic upper-torso phantom maps the radiation distribution as a simulated human body installed outside (MTR-1) and inside different compartments (MTR-2A: Pirs; MTR-2B: Zvezda) of the Russian Segment of the International Space Station. Thermoluminescence dosimeters arranged in a 2.54 cm orthogonal grid, at the site of vital organs and on the surface of the phantom allow for visualization of the absorbed dose distribution with superior spatial resolution. These results should help improve the estimation of radiation risks for long-term human space exploration and support benchmarking of radiation transport codes. [ABSTRACT FROM AUTHOR]

Lichens, which are symbioses of a fungus and one or two photoautotrophs, frequently tolerate extreme environmental conditions. This makes them valuable model systems in astrobiological research to fathom the limits and limitations of eukaryotic symbioses. Various studies demonstrated the high resistance of selected extremotolerant lichens towards extreme, non-terrestrial abiotic factors including space exposure, hypervelocity impact simulations as well as space and Martian parameter simulations. This study focusses on the diverse set of secondary lichen compounds (SLCs) that act as photo- and UVR-protective substances. Five lichen species used in present-day astrobiological research were compared: Buellia frigida, Circinaria gyrosa, Rhizocarpon geographicum, Xanthoria elegans, and Pleopsidium chlorophanum. Detailed investigation of secondary substances including photosynthetic pigments was performed for whole lichen thalli but also for axenically cultivated mycobionts and photobionts by methods of UV/VIS-spectrophotometry and two types of high performance liquid chromatography (HPLC). Additionally, a set of chemical tests is presented to confirm the formation of melanic compounds in lichen and mycobiont samples. All investigated lichens reveal various sets of SLCs, except C. gyrosa where only melanin was putatively identified. Such studies will help to assess the contribution of SLCs on lichen extremotolerance, to understand the adaptation of lichens to prevalent abiotic stressors of the respective habitat, and to form a basis for interpreting recent and future astrobiological experiments. As most of the identified SLCs demonstrated a high capacity in absorbing UVR, they may also explain the high resistance of lichens towards non-terrestrial UVR. [ABSTRACT FROM AUTHOR]

Greatly increased levels of ultraviolet (UV) radiation were observed at thirteen Arctic and sub-Arctic ground stations in the spring of 2011, when the ozone abundance in the Arctic stratosphere dropped to the lowest amounts on record. Measurements of the noontime UV Index (UVI) during the low-ozone episode exceeded the climatological mean by up to 77% at locations in the western Arctic (Alaska, Canada, Greenland) and by up to 161% in Scandinavia. The UVI measured at the end of March at the Scandinavian sites was comparable to that typically observed 15-60 days later in the year when solar elevations are much higher. The cumulative UV dose measured during the period of the ozone anomaly exceeded the climatological mean by more than two standard deviations at 11 sites. Enhancements beyond three standard deviations were observed at seven sites and increases beyond four standard deviations at two sites. At the western sites, the episode occurred in March, when the Sun was still low in the sky, limiting absolute UVI anomalies to less than 0.5 UVI units. At the Scandinavian sites, absolute UVI anomalies ranged between 1.0 and 2.2UVI units. For example, at Finse, Norway, the noontime UVI on 30 March was 4.7, while the climatological UVI is 2.5. Although a UVI of 4.7 is still considered moderate, UV levels of this amount can lead to sunburn and photokeratitis during outdoor activity when radiation is reflected upward by snow towards the face of a person or animal. At the western sites, UV anomalies can be well explained with ozone anomalies of up to 41% below the climatological mean. At the Scandinavian sites, low ozone can only explain a UVI increase of 50-60 %. The remaining enhancement was mainly caused by the absence of clouds during the low-ozone period. [ABSTRACT FROM AUTHOR]

The electrical properties of biological cells have connections to their pathological states. Here we present an electric impedance microflow cytometry (EIMC) platform for the characterization of disease states of single cells. This platform entails a microfluidic device for a label-free and non-invasive cell-counting assay through electric impedance sensing. We identified a dimensionless offset parameter δ obtained as a linear combination of a normalized phase shift and a normalized magnitude shift in electric impedance to differentiate cells on the basis of their pathological states. This paper discusses a representative case study on red blood cells (RBCs) invaded by the malaria parasite Plasmodium falciparum. Invasion by P. falciparum induces physical and biochemical changes on the host cells throughout a 48-h multi-stage life cycle within the RBC. As a consequence, it also induces progressive changes in electrical properties of the host cells. We demonstrate that the EIMC system in combination with data analysis involving the new offset parameter allows differentiation of P. falciparum infected RBCs from uninfected RBCs as well as among different P. falciparum intraerythrocytic asexual stages including the ring stage. The representative results provided here also point to the potential of the proposed experimental and analysis platform as a valuable tool for non-invasive diagnostics of a wide variety of disease states and for cell separation. [ABSTRACT FROM AUTHOR]

Residues of quaternary ammonium compounds ( QACs) remaining after sanitising were evaluated for a number of materials used in food plants. The residues were collected by swabs and measured using a spectrophotometric method. Surface topography and energy affected the QACs recovery. Highest percentage of QACs recovery was achieved for the tile material (102.2%) which had the most hydrophilic properties and least irregularities in surface topology, followed by stainless steel (82.1%). Meanwhile, the lowest recovery occurred in PVC (42.1%) and resin (44.3%) that exhibited hydrophobic characteristics and abrupt changes in height profile in a given surface area. Monitoring of QACs residues deposited on the surfaces after 7 days showed that the recovery of QACs in PVC and resin reduced significantly ( P < 0.05), supposing that QACs might be degraded or interacted with the materials. However, no significant changes in residue recovery were observed for tiles and stainless steel surfaces after 7 days. [ABSTRACT FROM AUTHOR]

Background: The lack of sensitive biocompatible particle track detectors has so far limited parallel detection of physical energy deposition and biological response. Fluorescent nuclear track detectors (FNTDs) based on Al2O3:C,Mg single crystals combined with confocal laser scanning microscopy (CLSM) provide 3D information on ion tracks with a resolution limited by light diffraction. Here we report the development of next generation cell-fluorescent ion track hybrid detectors (Cell-Fit-HD). Methods: The biocompatibility of FNTDs was tested using six different cell lines, i.e. human non-small cell lung carcinoma (A549), glioblastoma (U87), androgen independent prostate cancer (PC3), epidermoid cancer (A431) and murine (VmDk) glioma SMA-560. To evaluate cell adherence, viability and conformal coverage of the crystals different seeding densities and alternative coating with extracellular matrix (fibronectin) was tested. Carbon irradiation was performed in Bragg peak (initial 270.55 MeV u-1). A series of cell compartment specific fluorescence stains including nuclear (HOECHST), membrane (Glut-1), cytoplasm (Calcein AM, CM-DiI) were tested on Cell-Fit-HDs and a single CLSM was employed to co-detect the physical (crystal) as well as the biological (cell layer) information. Results: The FNTD provides a biocompatible surface. Among the cells tested, A549 cells formed the most uniform, viable, tightly packed epithelial like monolayer. The ion track information was not compromised in Cell-Fit-HD as compared to the FNTD alone. Neither cell coating and culturing, nor additional staining procedures affected the properties of the FNTD surface to detect ion tracks. Standard immunofluorescence and live staining procedures could be employed to co-register cell biology and ion track information. Conclusions: The Cell-Fit-Hybrid Detector system is a promising platform for a multitude of studies linking biological response to energy deposition at high level of optical microscopy resolution. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of a disinfectant onto viruses in suspension on the one hand and applied onto a surface on the other. Methods: A system combining flocked swabs to recover viruses dried onto stainless steel carriers and gel filtration to eliminate cytotoxic products has been developed to study the virucidal effect of a quaternary ammonium-based disinfectant towards herpes simplex virus type 1 (HSV-1), coxsackievirus B4 (CVB4) and feline calicivirus F9 (FCV). The recovery of FCV has been estimated by RT real-time PCR. Results: HSV-1, CVB4 and FCV had a titer over 104 TCID50 · ml-1 after 2 h drying and were recovered from the carriers using flocked swabs. HSV-1 was inactivated in suspension and on stainless steel carriers by the disinfectant (a reduction factor of 4 and 2.83 log, respectively) whereas CVB4 was resistant. The reduction of infectious titer was moderate, 1.5 log in 30 min, when FCV was in suspension, whereas it was up to 4 log in 10 min when the virus was dried on a carrier. Dried FCV was efficiently recovered from carriers as demonstrated by RT real-time PCR. Conclusion: A non-enveloped virus, FCV, applied on a surface, but not in suspension, was inactivated by a quaternary ammonium-based disinfectant. The resistance of viruses applied onto a surface to the effect of disinfectants should be investigated further. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Lichens are symbioses of two organisms, a fungal mycobiont and a photoautotrophic photobiont. In nature, many lichens tolerate extreme environmental conditions and thus became valuable models in astrobiological research to fathom biological resistance towards non-terrestrial conditions; including space exposure, hypervelocity impact simulations as well as space and Martian parameter simulations. All studies demonstrated the high resistance towards non-terrestrial abiotic factors of selected extremotolerant lichens. Besides other adaptations, this study focuses on the morphological and anatomical traits by comparing five lichen species- Circinaria gyrosa, Rhizocarpon geographicum, Xanthoria elegans, Buellia frigida, Pleopsidium chlorophanum-used in present-day astrobiological research. Detailed investigation of thallus organization by microscopy methods allows to study the effect of morphology on lichen resistance and forms a basis for interpreting data of recent and future experiments. All investigated lichens reveal a common heteromerous thallus structure but diverging sets of morphological-anatomical traits, as intra-/extra-thalline mucilage matrices, cortices, algal arrangements, and hyphal strands. In B. frigida, R. geographicum, and X. elegans the combination of pigmented cortex, algal arrangement, and mucilage seems to enhance resistance, while subcortex and algal clustering seem to be crucial in C. gyrosa, as well as pigmented cortices and basal thallus protrusions in P. chlorophanum. Thus, generalizations on morphologically conferred resistance have to be avoided. Such differences might reflect the diverging evolutionary histories and are advantageous by adapting lichens to prevalent abiotic stressors. The peculiar lichen morphology demonstrates its remarkable stake in resisting extreme terrestrial conditions and may explain the high resistance of lichens found in astrobiological research. [ABSTRACT FROM AUTHOR]

ABSTRACT Deinococcus radiodurans is known for its extraordinary resistance to various DNA damaging agents including γ-radiation and desiccation. The pqqE:cat and Δ dr2518 mutants making these cells devoid of pyrroloquinoline quinone (PQQ) and a PQQ inducible Ser/Thr protein kinase, respectively, became sensitive to γ-radiation. Transcriptome analysis of these mutants showed differential expression of the genes including those play roles in oxidative stress tolerance and (DSB) repair in D. radiodurans and in genome maintenance and stress response in other bacteria. Escherichia coli cells expressing DR2518 and PQQ showed improved resistance to γ-radiation, which increased further when both DR2518 and PQQ were present together. Although, profiles of genes getting affected in these mutants were different, there were still a few common genes showing similar expression trends in both the mutants and some others as reported earlier in oxyR and pprI mutant of this bacterium. These results suggested that PQQ and DR2518 have independent roles in γ-radiation resistance of D. radiodurans but their co-existence improves radioresistance further, possibly by regulating differential expression of the genes important for bacterial response to oxidative stress and DNA damage. [ABSTRACT FROM AUTHOR]

Aim The aim of this study was to develop a method to calculate the performance, and isolate error contributions occurring in a microbial surface sampling protocol. Methods and Results The experiments were conducted using a slip/peel tester to provide consistent pressure during the wipe collection. Fluorescence microscopy was used to count spores deposited on the coupon prior to sampling. The mean recovery efficiency ( RE) as well as the efficiency of each step in the process was estimated by a recovery balance ( RB), similar to a mass balance. Two studies were conducted in this work. In the first one, the recovery of spores from the solution ( REsoln) was 57·7% ( SD = 8·0), while spores left on the glass surface after wiping ( REb+c) was 2·8% ( SD = 2·4). The RE of spores adhered to the tube wall ( REtube) and glass surface ( REsurf) was 1·2% ( SD = 19·6) and 5·8% ( SD = 7·1), respectively. From the recovery balance, it was determined that 39·9% ( SD = 21·2) of spores were lost to the wipe ( REwipe). The applicability of the RB method was demonstrated in a second study by examining the relative impact of parameters affecting spore collection including relative humidity, wipe material, wetting agent and nonporous surfaces. Conclusions The approach used in this study pointed out the need for a closer analysis of the complex interaction between spores and wipe material because a substantial percentage of spores were lost to the wipe. Significance and Impact of the Study The recovery balance, in association with independent controls, provides an account for error contribution and potential variability on each step of the sampling protocol. The approach is not meant to be a replacement for field or laboratory validation of wipe recoveries but promote the development of new collection methodologies and support protocol optimization in laboratory settings. [ABSTRACT FROM AUTHOR]

Opportunistic fungal pathogens may cause an array of superficial infections or serious invasive infections, especially in immunocompromised patients. Cryptococcus neoformans is a pathogen causing cryptococcosis in HIV/AIDS patients, but treatment is limited due to the relative lack of potent antifungal agents. Photodynamic inactivation (PDI) uses the combination of non-toxic dyes called photosensitizers and harmless visible light, which produces singlet oxygen and other reactive oxygen species that produce cell inactivation and death. We report the use of five structurally unrelated photosensitizers (methylene blue, Rose Bengal, selenium derivative of a Nile blue dye, a cationic fullerene and a conjugate between poly-L-lysine and chlorin(e6)) combined with appropriate wavelengths of light to inactivate C. neoformans. Mutants lacking capsule and laccase, and culture conditions that favoured melanin production were used to probe the mechanisms of PDI and the effect of virulence factors. The presence of cell wall, laccase and melanin tended to protect against PDI, but the choice of the appropriate photosensitizers and dosimetry was able to overcome this resistance. [ABSTRACT FROM AUTHOR]

Purpose: By extending to other animal models the experiments on irradiated rabbit testes performed by the German Albers-Schönberg and Frieben and inspired by the preliminary observations of Regaud on spermatogenesis after irradiation, Bergonié and Tribondeau established a link between radiosensitivity and proliferation as a 'law' in 1906. Although it is still popular and taken as one of the founding laws of radiation oncology, it was early considered as a 'first approximation'. Conclusions: More than 100 years later, one tribute paid to these pioneers should be to at least avoid mixing notions like radiosensitivity, proliferation, differentiation, stem cells that they deeply contributed to define and to re-read their works in their original version in order to better understand what the technological and conceptual advances really are today. [ABSTRACT FROM AUTHOR]

The complex space environments can influence cell structure and function. The research results on space biology have shown that the major mutagenic factors in space are microgravity and ionizing radiation. In addition, possible synergistic effects of radiation and microgravity on human cells are not well understood. In this study, human immortal lymphoblastoid cells were established from human peripheral blood lymphocytes and the cells were treated with low dose (0.1, 0.15 and 0.2 Gy) cumulative Co γ-irradiation and simulated weightlessness [obtained by culturing cells in the Rotating Cell Culture System (RCCS)]. The commonly used indexes of cell damage such as micronucleus rate, cell cycle and mitotic index were studied. Previous work has proved that Gadd45 (growth arrest and DNA-damage-inducible protein 45) gene increases with a dose-effect relationship, and will possibly be a new biological dosimeter to show irradiation damage. So Gadd45 expression is also detected in this study. The micronucleus rate and the expression of Gadd45α gene increased with irradiation dose and were much higher after incubation in the rotating bioreactor than that in the static irradiation group, while the cell proliferation after incubation in the rotating bioreactor decreased at the same time. These results indicate synergetic effects of simulated weightlessness and low dose irradiation in human cells. The cell damage inflicted by γ-irradiation increased under simulated weightlessness. Our results suggest that during medium- and long-term flight, the human body can be damaged by cumulative low dose radiation, and the damage will even be increased by microgravity in space. [ABSTRACT FROM AUTHOR]

Solar-driven evaporation is a promising way of using abundant solar energy for desalinating polluted water or seawater, which addresses the challenge of global fresh water scarcity. Cost-effectiveness and durability are key factors for practical solar-driven evaporation technology. The present cutting-edge techniques mostly rely on costly and complex fabricated nanomaterials, such as metallic nanoparticles, nanotubes, nanoporous hydrogels, graphene, and graphene derivatives. Herein, a black nylon fiber (BNF) flocking board with a vertically aligned array prepared via a convenient electrostatic flocking technique is reported, presenting an extremely high solar absorbance (99.6%), a water self-supply capability, and a unique salt self-dissolution capability for seawater desalination. Through a carefully designed 3D structure, a plug-in-type BNF flocking board steam generator realizes a high evaporation rate of 2.09 kg m -2 h -1 under 1 kW m -2 solar illumination, well beyond its corresponding upper limit of 1.50 kg m -2 h -1 (assuming 100% solar energy is being used for evaporation latent heat). With the advantages of high-efficiency fabrication, cost-effectiveness, high evaporation rate, and high endurance in seawater desalination, this 3D design provides a new strategy to build up an economic, sustainable, and rapid solar-driven steam generation system., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This paper presents a search for the t-channel exchange of an R-parity violating scalar top quark () in the e±μ∓ continuum using 2.1 fb−1 of data collected by the ATLAS detector in pp collisions at the Large Hadron Collider. Data are found to be consistent with the expectation from the Standard Model backgrounds. Limits on R-parity-violating couplings at 95 % C.L. are calculated as a function of the scalar top mass (). The upper limits on the production cross section for pp→eμX, through the t-channel exchange of a scalar top quark, ranges from 170 fb for to 30 fb for . [ABSTRACT FROM AUTHOR]

With the increased international emphasis on manned space exploration, there is a growing need to understand the impact of the spaceflight environment on health and behavior. One particularly important aspect of this environment is low-dose radiation. In the present studies, we first characterized the γ- and proton-irradiation dose effect on acoustic startle and pre-pulse inhibition behaviors in mice exposed to 0-5 Gy brain-localized irradiation, and assessed these effects 2 days later. Subsequently, we used 2 Gy to assess the time course of γ- and proton-radiation effects on startle reactivity 0-8 days after exposure. Exposures targeted the brain to minimize the impact of peripheral inflammation-induced sickness behavior. The effects of radiation on startle were subtle and acute. Radiation reduced the startle response at 2 and 5 Gy. Following a 2-Gy exposure, the response reached a minimum at the 2-day point. Proton and γ-ray exposures did not differ in their impact on startle. We found there were no effects of radiation on pre-pulse inhibition of the startle response. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the effectiveness of two spray-based decontamination methods for surface contamination reduction and to determine the potential for contamination spread by these methods. Methods and Results: Material coupons (treated plywood and concrete) were contaminated with c. 1 × 107 spores of Bacillus atrophaeus by aerosol deposition. Decontaminants (pH-adjusted bleach or Spor-Klenz® RTU) were applied to coupons by either backpack sprayer or gas-powered sprayer. Contact time, reapplication frequency and rinse method were also varied. In addition to surface removal efficacy, partitioning of contamination between the rinsate and aerosol fractions was determined. Results indicated that pH-adjusted bleach was effective (≥6 logs reduction) when two applications and a 30 min contact time were administered, regardless of the decontaminant application method or material. Spor-Klenz® RTU was effective on wood, but achieved ≤3 logs reduction on concrete. A shortened application procedure with pH-adjusted bleach resulted in lower efficacy on wood, and a greater apparent potential for contamination spread. Conclusions: Consideration of material surface type is important when selecting a decontaminant. Also, achieving conditions that effectively inactivate surface biological contamination are critical to preventing the spread of contamination. Significance and Impact of the Study: Results presented here are intended to help development of remediation plans following a biological contamination incident. [ABSTRACT FROM AUTHOR]

The differentiation between living and dead bacterial endospores is crucial in many research areas of microbiology. The identification of inactivated, non-pathogenic Bacillus anthracis spores is one reason why improvement of decontamination protocols is so desirable. Another field interested in spore viability is planetary protection, a sub-discipline of astrobiology that estimates the bioburden of spacecraft prior to launch in order to avoid interplanetary cross-contamination. We developed a dedicated, rapid and cost-effective method for identifying bacterial endospores that have been inactivated and consequently show a compromised spore wall. This novel protocol is culture-independent and is based on fluorescence microscopy and propidium monoazide (PMA) as a fluorescent marker, which is suggested to bind to DNA of spores with compromised spore coat, cortex and membranes based on our results. Inactivated preparations (treated with wet heat, irradiation, ultracentrifugation) showed a significant increase in spores that were PMA stained in their core; moreover, Bacillus atrophaeus, Bacillus safensis and Geobacillus stearothermophilus seemed to be best suited for this technique, as the spore cores of all these endospores could be positively stained after inactivation. Lastly, we describe an additional counter-staining protocol and provide an example of the application of the coupled staining methods for planetary protection purposes. The introduction of this novel protocol is expected to provide an initial insight into the various possible future applications of PMA as a non-viability marker for spores in, for example, B. anthracis-related studies, food microbiology and astrobiology. [ABSTRACT FROM AUTHOR]

Objective: The aim of this in vitro study was to compare the antimicrobial effects of photodynamic antimicrobial chemotherapy (PACT), an ordinary antiseptic (chlorhexidini digluconas), and an antibiotic therapy (bacitracinum zincicum and neomycini sulfas) in vitro. Background: Photodynamic therapy (PDT) is an area of great interest for its potential use as an antimicrobial therapy. It is currently a popular topic in modern medical literature. PDT is, according to recent publications, advantageous over other types of therapies because it acts nonspecifically and it is impossible to develop resistance to the therapy. Materials and Methods: We investigated the antibacterial effect of these three forms of antiseptics on the selection of G+, G-, aerobic, and anaerobic bacteria that exist in the oral cavity and are involved in the formation of periodontal diseases. Results & Conclusion: We found that the PACT device did not have a sufficient antimicrobial effect in vitro. In contrast, the disinfection agents containing chlorhexidini digluconas were effective and may be a safe, non-specific alternative to antibiotic treatments. Promising results from some clinical studies can have different mechanism of action as disinfection. [ABSTRACT FROM AUTHOR]

Background: Ionizing radiation (IR) can be extremely harmful for human cells since an improper DNA-damage response (DDR) to IR can contribute to carcinogenesis initiation. Perturbations in DDR pathway can originate from alteration in the functionality of the microRNA-mediated gene regulation, being microRNAs (miRNAs) small noncoding RNA that act as posttranscriptional regulators of gene expression. In this study we gained insight into the role of miRNAs in the regulation of DDR to IR under microgravity, a condition of weightlessness experienced by astronauts during space missions, which could have a synergistic action on cells, increasing the risk of radiation exposure. Methodology/Principal Findings: We analyzed miRNA expression profile of human peripheral blood lymphocytes (PBL) incubated for 4 and 24 h in normal gravity (1 g) and in modeled microgravity (MMG) during the repair time after irradiation with 0.2 and 2Gy of γ-rays. Our results show that MMG alters miRNA expression signature of irradiated PBL by decreasing the number of radio-responsive miRNAs. Moreover, let-7iး, miR-7, miR-7-1း, miR-27a, miR-144, miR-200a, miR-598, miR-650 are deregulated by the combined action of radiation and MMG. Integrated analyses of miRNA and mRNA expression profiles, carried out on PBL of the same donors, identified significant miRNA-mRNA anti-correlations of DDR pathway. Gene Ontology analysis reports that the biological category of "Response to DNA damage" is enriched when PBL are incubated in 1 g but not in MMG. Moreover, some anti-correlated genes of p53-pathway show a different expression level between 1 g and MMG. Functional validation assays using luciferase reporter constructs confirmed miRNA-mRNA interactions derived from target prediction analyses. Conclusions/Significance: On the whole, by integrating the transcriptome and microRNome, we provide evidence that modeled microgravity can affects the DNA-damage response to IR in human PBL. [ABSTRACT FROM AUTHOR]

In this study, we investigated the ability of several (hyper-) thermophilic Archaea and phylogenetically deep-branching thermophilic Bacteria to survive high fluences of monochromatic UV-C (254 nm) and high doses of ionizing radiation, respectively. Nine out of fourteen tested microorganisms showed a surprisingly high tolerance against ionizing radiation, and two species ( Aquifex pyrophilus and Ignicoccus hospitalis) were even able to survive 20 kGy. Therefore, these species had a comparable survivability after exposure to ionizing radiation such as Deinococcus radiodurans. In contrast, there was nearly no difference in survival of the tested strains after exposure to UV-C under anoxic conditions. If the cells had been dried in advance of UV-C irradiation, they were more sensitive to UV-C radiation compared with cells irradiated in liquid suspension; this effect could be reversed by the addition of protective material like sulfidic ores before irradiation. By exposure to UV-C, photoproducts were formed in the DNA of irradiated Archaea and Bacteria. The distribution of the main photoproducts was species specific, but the amount of the photoproducts was only partly dependent on the applied fluence. Overall, our results show that tolerance to radiation seems to be a common phenomenon among thermophilic and hyperthermophilic microorganisms. [ABSTRACT FROM AUTHOR]

ABSTRACT Combinations of FD&C Red no. 3 and high-pressure processing (HPP) effectively inactivate various important processing-resistant spoilage and pathogenic bacteria in buffer; however, the lethality is unverified in food. The objective of this study was to determine the efficacy of HPP-Red 3 to inactivate Listeria monocytogenes and Escherichia coli O157:H7 in two food systems. Sterile carrot juice and turkey product were inoculated with stationary-phase cells and treated with HPP-Red 3. Red 3 concentrations of 10-100 ppm in carrot juice with HPP (500 MPa, 1 min, 23C) produced synergistic inactivation of L. monocytogenes. HPP-Red 3 (100 ppm) combinations in carrot juice caused synergistic inactivation of E. coli. HPP was ineffective at reducing L. monocytogenes in pre-cooked luncheon turkey product. HPP reduced E. coli in turkey product (3.9 log reduction); however, combination treatment did not significantly increase lethality, regardless of Red 3 concentration. Food systems significantly impact the efficacy of HPP-Red 3 against foodborne pathogens. PRACTICAL APPLICATIONS FD&C Red no. 3 is approved for use in most food products at levels up to 300 ppm to enhance the color of products. This colorant also possesses antimicrobial properties against gram-positive bacteria, due to the production of photooxidative species (superoxide, singlet oxygen, etc.). Interestingly, combining Red 3 with high-pressure processing (HPP) treatment produces synergistic inactivation of both gram-positive and gram-negative bacteria with and without light exposure (485 lux). Inclusion of Red 3 in product formulation and inclusion of HPP as a lethal processing step could be utilized by the food industry to enhance the shelf-life and safety of food products. Other certified food colorants could be used to adjust the color of the final product without altering the antimicrobial effect of the combination treatment. Efficacy of combination treatment needs to be validated for specific food systems. [ABSTRACT FROM AUTHOR]

The story of prevention and control of infectious diseases remains open and a series of highly virulent pathogens are emerging both in and beyond the hospital setting. Antibiotics were an absolute success story for a previous era. The academic and industrial biomedical communities have now come together to formulate consensus beliefs regarding the pursuit of novel and effective alternative anti-infective countermeasures. Photodynamic therapy was established and remains a successful modality for malignancies but photodynamic inactivation has been transformed recently to an antimicrobial discovery and development platform. The concept of photodynamic inactivation is quite straightforward and requires microbial exposure to ligh energy, typically wavelengths in the visible region, that causes the excitation of photosensitizer molecules (either exogenous or endogenous), which results in the production of single oxygen and other reactive oxygen species that react with intracellular components, and consequently produce cel inactivation. It is an area of increasing interest, as research is advancing (1) to identify the photochemical and photophysica mechanisms involved in inactivation, (2) to develop potent and clinically compatible photosensitizer, (3) to understand how photoinactivation is affected by key microbial phenotypic elements (multidrug resistance and efflux, virulence and pathogenesis determinants, biofilms), (4) to explore nove delivery platforms inspired by current trends in pharmacology and nanotechnology and (5) to identify photoinactivation applications beyond the clinical setting such as environmenta disinfectants. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the associations between airborne and dustborne microbial contaminants (endotoxin and β-d-glucan) and estimate the effects of home characteristics on exposure levels of these microbial contaminants. Endotoxin and β-d-glucan concentrations in airborne inhalable particles, airborne PM1 (＜1 μm) and vacuumed dust from 184 residential homes were determined using specific Limulus amebocyte assays. Home characteristics were recorded by visual inspection and questionnaires. Linear regression and correlation analyses were performed. Inhalable endotoxin correlated with dust endotoxin (r = 0.34, p ＜ 0.001) and PM1 endotoxin (r = 0.33, p ＜ 0.001). Inhalable β-d-glucan correlated with dust β-d-glucan (r = 0.18, p ＜ 0.01), but not with PM1 β-d-glucan. Significant correlation was also found between PM1 and dust concentrations for endotoxin (r = 0.26, p ＜ 0.001), but not for β-d-glucan. Multivariate regression analyses showed only one significant association between airborne contaminants and environmental characteristics: inhalable β-d-glucan was positively associated with relative humidity with an effect size (change in the dependent variable corresponding to a unit increase in the independent variable) of 2.32 and p ＜ 0.05. In contrast, several associations were found between dust concentrations and environmental characteristics. Dust endotoxin was positively associated with temperature (2.87, p ＜ 0.01) and number of inhabitants (2.76, p ＜ 0.01), whereas dust β-d-glucan was inversely associated with the presence of dogs (−2.24, p ＜ 0.05) and carpet (−3.05, p ＜ 0.01) in the home. In conclusion, dustborne contaminants were more strongly affected by home characteristics than airborne contaminants. Furthermore, even though statistically significant, the correlations between airborne and dustborne contaminants were weak. This indicates that airborne concentrations cannot be reliably predicted based on dustborne concentrations. [ABSTRACT FROM AUTHOR]

An epilithic microbial community was launched into low Earth orbit, and exposed to conditions in outer space for 548 days on the European Space Agency EXPOSE-E facility outside the International Space Station. The natural phototroph biofilm was augmented with akinetes of Anabaena cylindrica and vegetative cells of Nostoc commune and Chroococcidiopsis. In space-exposed dark controls, two algae (Chlorella and Rosenvingiella spp.), a cyanobacterium (Gloeocapsa sp.) and two bacteria associated with the natural community survived. Of the augmented organisms, cells of A. cylindrica and Chroococcidiopsis survived, but no cells of N. commune. Only cells of Chroococcidiopsis were cultured from samples exposed to the unattenuated extraterrestrial ultraviolet (UV) spectrum (>110 nm or 200 nm). Raman spectroscopy and bright-field microscopy showed that under these conditions the surface cells were bleached and their carotenoids were destroyed, although cell morphology was preserved. These experiments demonstrate that outer space can act as a selection pressure on the composition of microbial communities. The results obtained from samples exposed to >200 nm UV (simulating the putative worst-case UV exposure on the early Earth) demonstrate the potential for epilithic colonization of land masses during that time, but that UV radiation on anoxic planets can act as a strong selection pressure on surface-dwelling organisms. Finally, these experiments have yielded new phototrophic organisms of potential use in biomass and oxygen production in space exploration. [ABSTRACT FROM AUTHOR]

Pigments such as melanin, scytonemin and carotenoids protect microbial cells against the harmful effects of ultraviolet (UV) radiation. The role in UV protection has never been assigned to the prodigiosin pigment. In this work, we demonstrate that prodigiosin provides a significant level of protection against UV stress in Vibrio sp. DSM 14379. In the absence of pigment production, Vibrio sp. was significantly more susceptible to UV stress, and there was no difference in UV survival between the wild-type strain and non-pigmented mutant. The pigment's protective role was more important at higher doses of UV irradiation and correlated with pigment concentration in the cell. Pigmented cells survived high UV exposure (324 J/m) around 1,000-fold more successfully compared to the non-pigmented mutant cells. Resistance to UV stress was conferred to the non-pigmented mutant by addition of exogenous pigment extract to the growth medium. A level of UV protection equivalent to that exhibited by the wild-type strain was attained by the non-pigmented mutant once the prodigiosin concentration had reached comparable levels to those found in the wild-type strain. In co-culture experiments, prodigiosin acted as a UV screen, protecting both the wild-type and non-pigmented mutants. Our results suggest a new ecophysiological role for prodigiosin. [ABSTRACT FROM AUTHOR]

Passive chambers are used to examine the impacts of summer warming in Antarctica but, so far, impacts occurring outside the growing season, or related to extreme temperatures, have not been reported, despite their potentially large biological significance. In this review, we synthesise and discuss the microclimate impacts of passive warming chambers (closed, ventilated and Open Top Chamber-OTC) commonly used in Antarctic terrestrial habitats, paying special attention to seasonal warming, during the growing season and outside, extreme temperatures and freeze-thaw events. Both temperature increases and decreases were recorded throughout the year. Closed chambers caused earlier spring soil thaw (8-28 days) while OTCs delayed soil thaw (3-13 days). Smaller closed chamber types recorded the largest temperature extremes (up to 20°C higher than ambient) and longest periods (up to 11 h) of above ambient extreme temperatures, and even OTCs had above ambient temperature extremes over up to 5 consecutive hours. The frequency of freeze-thaw events was reduced by ~25%. All chamber types experienced extreme temperature ranges that could negatively affect biological responses, while warming during winter could result in depletion of limited metabolic resources. The effects outside the growing season could be as important in driving biological responses as the mean summer warming. We make suggestions for improving season-specific warming simulations and propose that seasonal and changed temperature patterns achieved under climate manipulations should be recognised explicitly in descriptions of treatment effects. [ABSTRACT FROM AUTHOR]

Purpose: Risk assessment of radiation exposure during long-term space missions requires the knowledge of the relative biological effectiveness (RBE) of space radiation components. Few data on gene transcription activation by different heavy ions are available, suggesting a dependence on linear energy transfer. The transcription factor Nuclear Factor κB (NF-κB) can be involved in cancerogenesis. Therefore, NF-κB activation by accelerated heavy ions of different linear energy transfer (LET) was correlated to survival. Materials and methods: NF-κB-dependent gene induction after exposure to heavy ions was detected in stably transfected human embryonic kidney 293 cells (HEK-pNF-κB-d2EGFP/Neo cells carrying a neomycin resistance), using the destabilized Enhanced Green Fluorescent Protein (d2EGFP) as reporter. Results: Argon (LET 272 keV/μm) and neon ions (LET 91 keV/μm) had the highest potential to activate NF-κB, resulting in a RBE of 8.9 in comparison to 150 kV X-rays. The RBE for survival also reached its maximum in this LET range, with a maximal value of 2. Conclusions: NF-κB might be involved in modulating survival responses of cells hit by heavy ions in the LET range of 91-272 keV/μm and could therefore become a factor to be considered for risk assessment of radiation exposure during space travel. [ABSTRACT FROM AUTHOR]

Several space agencies and exploration stakeholders have a strong interest in obtaining information on technical and human aspects to prepare for future extra-terrestrial planetary exploration. In this context, the EuroGeoMars campaign, organized with support from the International Lunar Exploration Working Group (ILEWG), the European Space Agency (ESA), the National Aeronautics and Space Administration (NASA) Ames Research Center and partner institutes, was conducted by the crews 76 and 77 in February 2009 in The Mars Society's ‘Mars Desert Research Station’ (MDRS) in Utah.The EuroGeoMars encompasses two groups of experiments: (1) a series of field science experiments that can be conducted from an extra-terrestrial planetary surface in geology, biology, astronomy/astrophysics and the necessary technology and networks to support these field investigations; (2) a series of human crew-related investigations on crew time organization in a planetary habitat, on the different functions and interfaces of this habitat, and on man–machine interfaces of science and technical equipment.This paper recalls the objective of the EuroGeoMars project and presents the MDRS and its habitat layout. Social and operational aspects during simulations are described. Technical and operational aspects of biology investigations in the field and in the habitat laboratory are discussed in detail with the focus point set on the polymerase chain reaction (PCR)-based detection of microbial DNA in soil samples. [ABSTRACT FROM AUTHOR]

Purpose: Quantitative analysis of cancer risk of ionising radiation as a function of dose-rate. Materials and methods: Non-tumour dose, Dnt, defined as the highest dose of radiation at which no statistically significant tumour increase was observed above the control level, was analysed as a function of dose-rate of radiation. Results: An inverse correlation was found between Dnt and dose-rate of the radiation. Dnt increased 20-fold with decreasing dose-rate from 1--10−−8 Gy/min for whole body irradiation with low linear energy transfer (LET) radiation. Partial body radiation also showed a dose-rate dependence with a 5- to 10-fold larger Dnt as dose rate decreased. The dose-rate effect was also found for high LET radiation but at 10-fold lower Dnt levels. Conclusions: The cancer risk of ionising radiation varies 1000-fold depending on the dose-rate of radiation and exposure conditions. This analysis explains the discrepancy of cancer risk between A-bomb survivors and radium dial painters. [ABSTRACT FROM AUTHOR]

Recent experiments have shown the possibility to use the brain electrical activity to directly control the movement of robots. Such a kind of brain-computer interface is a natural way to augment human capabilities by providing a new interaction link with the outside world and is particularly relevant as an aid for paralysed humans, although it also opens up new possibilities in human-robot interaction for able-bodied people. One of these new fields of application is the use of brain-computer interfaces in the space environment, where astronauts are subject to extreme conditions and could greatly benefit from direct mental teleoperation of external semi-automatic manipulators-for instance, mental commands could be sent without any output/latency delays, as it is the case for manual control in microgravity conditions. Previous studies show that there is a considerable potential for this technology onboard spacecraft. [ABSTRACT FROM AUTHOR]