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Research Containing: Microbiology

Comparison of antibiotic resistance, biofilm formation and conjugative transfer of Staphylococcus and Enterococcus isolates from International Space Station and Antarctic Research Station Concordia

by on 9 June 2015in Biology & Biotechnology No comment

The International Space Station (ISS) and the Antarctic Research Station Concordia are confined and isolated habitats in extreme and hostile environments. The human and habitat microflora can alter due to the special environmental conditions resulting in microbial contamination and health risk for the crew. In this study, 29 isolates from the ISS and 55 from the Antarctic Research Station Concordia belonging to the genera Staphylococcus and Enterococcus were investigated. Resistance to one or more antibiotics was detected in 75.8 % of the ISS and in 43.6 % of the Concordia strains. The corresponding resistance genes were identified by polymerase chain reaction in 86 % of the resistant ISS strains and in 18.2 % of the resistant Concordia strains. Plasmids are present in 86.2 % of the ISS and in 78.2 % of the Concordia strains. Eight Enterococcus faecalis strains (ISS) harbor plasmids of about 130 kb. Relaxase and/or transfer genes encoded on plasmids from gram-positive bacteria like pIP501, pRE25, pSK41, pGO1 and pT181 were detected in 86.2 % of the ISS and in 52.7 % of the Concordia strains. Most pSK41-homologous transfer genes were detected in ISS isolates belonging to coagulase-negative staphylococci. We demonstrated through mating experiments that Staphylococcus haemolyticus F2 (ISS) and the Concordia strain Staphylococcus hominis subsp. hominis G2 can transfer resistance genes to E. faecalis and Staphylococcus aureus, respectively. Biofilm formation was observed in 83 % of the ISS and in 92.7 % of the Concordia strains. In conclusion, the ISS isolates were shown to encode more resistance genes and possess a higher gene transfer capacity due to the presence of three vir signature genes, virB1, virB4 and virD4 than the Concordia isolates.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/23411852

Microbe-I: fungal biota analyses of the Japanese experimental module KIBO of the International Space Station before launch and after being in orbit for about 460 days

by on 9 June 2015in Biology & Biotechnology No comment

In addition to the crew, microbes also find their way aboard the International Space Station (ISS). Therefore, microbial monitoring is necessary for the health and safety of the crew and for general maintenance of the facilities of this station. Samples were collected from three sites in the Japanese experimental module KIBO on the ISS (air diffuser, handrail, and surfaces) for analysis of fungal biota approximately 1 year after this module had docked with the ISS. Samples taken from KIBO before launch and from our laboratory were used as controls. In the case of KIBO, both microbe detection sheet (MDS) and swab culture tests of orbital samples were negative. The MDS were also examined by field emission-scanning electron microscopy; no microbial structures were detected. However, fungal DNAs were detected by real-time PCR and analyzed by the clone library method; Alternaria sp. and Malassezia spp. were the dominant species before launch and in space, respectively. The dominant species found in specimens from the air conditioner diffuser, lab bench, door push panel, and facility surfaces on our laboratory (ground controls) were Inonotus sp., Cladosporium sp., Malassezia spp., and Pezicula sp., respectively. The fungi in the KIBO were probably derived from contamination due to humans, while those in our laboratory came from the environment (e.g., the soil). In conclusion, the cleanliness in KIBO was equivalent to that in a clean room environment on the ground.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/21950271

Characterization of Volume F trash from the three FY11 STS missions: Trash weights and categorization and microbial characterization

by on 9 June 2015in Biology & Biotechnology No comment

This research project provided microbial characterization support to the Waste Management Systems (WMS) element of NASA's Life Support and Habitation Systems (LSHS) program. Conventional microbiological methods were used to detect and enumerate microorganisms in space-generated solid wastes, i.e., STS Volume F Compartment trash returned from orbit and missions to ISS. Crew generated STS trash was characterized for three shuttle missions: STS 133, STS 134, and STS 135. The waste was catalogued into logical categories, weighed, and the water content determined. Results for FY11 STS missions showed more variability than for the FYlO study of STS 129-132 and indicated some waste was probably not included in what was returned to KSC on the STS. Microbial characterization of wastes from each mission and each category determined the presence of high numbers of microbes in food waste and food packaging, in drink pouches, and in personal hygiene wastes. A number of bacteria and fungi were identified, including known pathogens and some likely opportunistic pathogens that could cause problems if these wastes were exposed to an immune compromised crew.

Related URLs:
http://dx.doi.org/10.2514/6.2012-3565

Microbial Characterization of Space Solid Wastes Treated with a Heat Melt Compactor

by on 9 June 2015in Biology & Biotechnology No comment

The purpose of the project has been to characterize and determine the fate of microorganisms in space-generated solid wastes before and after processing by candidate solid waste processing. For FY11, the Heat Melt Compactor (HMC) was the candidate technology that was assessed. Five HMC product disks were produced at ARC from either simulated space-generated trash or from actual space trash. The actual space trash was the STS 130 Volume F compartment wet waste. Conventional microbiological methods were used to detect and enumerate microorganisms in heat melt compaction (HMC) product disks and in surface swab samples of the HMC hardware before and after operation. In addition, biological indicators were added to the STS trash prior to compaction to determine if these spore-forming bacteria could survive the HMC processing conditions, i.e., high temperature (160°C) over a long duration (3 hrs). The HMC disk surfaces were sanitized with 70% alcohol prior to obtaining the core samples to ensure that surface dwelling microbes did not contaminate the HMC product disk interior. Microbiological assays were run before and after sanitization and found that sanitization greatly reduced, but did not eliminate, the number of identified isolate. To characterize the interior of the disks, ten 1.25cm diameter core samples were aseptically obtained from each disk. These were run through the microbial characterization analyses. Low counts of bacteria, on the order of 5 to 50 viable cells per core, were found, indicating that the HMC operating conditions might not be sufficient for absolute sterilization of the waste. However, the direct counts were 6 to 8 orders of magnitude greater, demonstrating that the vast majority of microbes present in the wastes were results from commercial spore test strops that had been added to the wastes prior to HMC operation. Nearly all could be recovered from the HMC disks post-operation and all were showed negative growth when run through the manufacturer’s protocol, meaning that the 1 x 106 or so spores impregnated into the strips were dead. Control test strips, i.e., not exposed to the HMC conditions, were all strongly positive. One area of concern is that the identities of isolates from the cultivable counts included several human pathogens namely Staphylococcus aureus.

Related URLs:
http://dx.doi.org/10.2514/6.2012-3546

Space habitation and microbiology: status and roadmap of space agencies

by on 9 June 2015in Biology & Biotechnology No comment

The ubiquitous nature of microbiology is reflected in the diversity of microbiological research and operational efforts at NASA. For example, the impact of microorganisms on other planets and the protection of Earth from the potential of microbial life elsewhere is the responsibility of the Office of Planetary Protection (http://planetaryprotection.nasa.gov/about). While the Office of Planetary Protection does not include forward or back contamination to or from a low Earth orbit, research platforms, such as the ISS, are being used to better understand the survival of microorganisms and corresponding contamination control in the extreme conditions of space (2, 4, 10). Another example is the NASA Center for Astrobiology, which focuses on the origin, evolution, distribution, and future of life in the universe (https://astrobiology.nasa.gov/). The large focus on microbiology is within its human exploration operations. NASA has historically set microbiological requirements, including stringent monitoring regimes, to mitigate risks to the health and performance of astronauts. Microorganisms can have both positive and negative impacts on many aspects of human spaceflight, including the risk and prevention of infectious diseases, performance of Environmental Control and Life Support Systems (ECLSS), spaceflight foods, and vehicle design and integrity. Even though a great amount of information has been obtained (1, 5, 7, 8), several key questions regarding the impact of microorganisms on human spaceflight still remain. Research into the uncertainties of risks that may affect crew health are the responsibility of the NASA Human Research Program (http://www.nasa.gov/exploration/humanresearch/). The research that addresses our fundamental understanding of space life science and its translation for benefits to the general public on Earth is the responsibility of NASA Space Biology.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/25130884

Microbial responses to microgravity and other low-shear environments

by on 9 June 2015in Biology & Biotechnology No comment

Microbial adaptation to environmental stimuli is essential for survival. While several of these stimuli have been studied in detail, recent studies have demonstrated an important role for a novel environmental parameter in which microgravity and the low fluid shear dynamics associated with microgravity globally regulate microbial gene expression, physiology, and pathogenesis. In addition to analyzing fundamental questions about microbial responses to spaceflight, these studies have demonstrated important applications for microbial responses to a ground-based, low-shear stress environment similar to that encountered during spaceflight. Moreover, the low-shear growth environment sensed by microbes during microgravity of spaceflight and during ground-based microgravity analogue culture is relevant to those encountered during their natural life cycles on Earth. While no mechanism has been clearly defined to explain how the mechanical force of fluid shear transmits intracellular signals to microbial cells at the molecular level, the fact that cross talk exists between microbial signal transduction systems holds intriguing possibilities that future studies might reveal common mechanotransduction themes between these systems and those used to sense and respond to low-shear stress and changes in gravitation forces. The study of microbial mechanotransduction may identify common conserved mechanisms used by cells to perceive changes in mechanical and/or physical forces, and it has the potential to provide valuable insight for understanding mechanosensing mechanisms in higher organisms. This review summarizes recent and future research trends aimed at understanding the dynamic effects of changes in the mechanical forces that occur in microgravity and other low-shear environments on a wide variety of important microbial parameters.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/15187188

Genes Required for Survival in Microgravity Revealed by Genome-Wide Yeast Deletion Collections Cultured during Spaceflight

by on 9 June 2015in Biology & Biotechnology No comment

Spaceflight is a unique environment with profound effects on biological systems including tissue redistribution and musculoskeletal stresses. However, the more subtle biological effects of spaceflight on cells and organisms are difficult to measure in a systematic, unbiased manner. Here we test the utility of the molecularly barcoded yeast deletion collection to provide a quantitative assessment of the effects of microgravity on a model organism. We developed robust hardware to screen, in parallel, the complete collection of ~4800 homozygous and ~5900 heterozygous (including ~1100 single-copy deletions of essential genes) yeast deletion strains, each carrying unique DNA that acts as strain identifiers. We compared strain fitness for the homozygous and heterozygous yeast deletion collections grown in spaceflight and ground, as well as plus and minus hyperosmolar sodium chloride, providing a second additive stressor. The genome-wide sensitivity profiles obtained from these treatments were then queried for their similarity to a compendium of drugs whose effects on the yeast collection have been previously reported. We found that the effects of spaceflight have high concordance with the effects of DNA-damaging agents and changes in redox state, suggesting mechanisms by which spaceflight may negatively affect cell fitness.

Related URLs:
http://dx.doi.org/10.1155/2015/976458

Survey of environmental biocontamination on board the International Space Station

by on 9 June 2015in Biology & Biotechnology No comment

The International Space Station (ISS) is an orbital living and working environment extending from the original Zarya control module built in 1998. The expected life span of the completed station is around 10 years and during this period it will be constantly manned. It is inevitable that the ISS will also be home to an unknown number of microorganisms. This survey reports on microbiological contamination in potable water, air, and on surfaces inside the ISS. The viable counts in potable water did not exceed 1.0 × 10 2   CFU / ml . Sphingomonas sp. and Methylobacterium sp. were identified as the dominant genera. Molecular analysis demonstrated the presence of nucleic acids belonging to various pathogens, but no viable pathogens were recovered. More than 500 samples were collected at different locations over a period of 6 years to characterize air and surface contamination in the ISS. Concentrations of airborne bacteria and fungi were lower than 7.1 × 10 2 and 4.4 × 10 1   CFU / m 3 , respectively. Staphylococcus sp. was by far the most dominant airborne bacterial genus, whereas Aspergillus sp. and Penicillium sp. dominated the fungal population. The bacterial concentrations in surface samples fluctuated from 2.5 × 10 1 to 4.3 × 10 4   CFU / 100   cm 2 . Staphylococcus sp. dominated in all of these samples. The number of fungi varied between 2.5 × 10 1 and 3.0 × 10 5   CFU / 100   cm 2 , with Aspergillus sp. and Cladosporium sp. as the most dominant genera. Furthermore, the investigations identified the presence of several (opportunistic) pathogens and strains involved in the biodegradation of structural materials.

Related URLs:
http://www.sciencedirect.com/science/article/pii/S0923250805002627

Survival of dormant organisms after long-term exposure to the space environment

by on 9 June 2015in Biology & Biotechnology No comment

The RF SRC—Institute of Biomedical Problems, Russian Academy of Sciences, developed Biorisk hardware to study the effects of long-term exposure of dormant forms of various organisms to outer space and used it to complete a series of experiments on the Russian Module (RM) of the International Space Station (ISS). The experiments were performed using prokaryotes (Bacillus bacteria) and eukaryotes (Penicillium, Aspergillus, and Cladosporium fungi), as well as spores, dormant forms of higher plants, insects, lower crustaceans, and vertebrates. The biological samples were housed in two containers that were exposed to outer space for 13 or 18 months. The results of the 18-month experiment showed that, in spite of harsher temperature than in the first study, most specimens remained viable. These experiments provided evidence that not only bacterial and fungal spores but also dormant forms of organisms that reached higher levels of evolutionary development had the capability to survive a long-term exposure to outer space. This observation suggests that they can be transferred on outer walls of space platforms during interplanetary missions.

Related URLs:
http://www.sciencedirect.com/science/article/pii/S0094576510001839

Novel quantitative biosystem for modeling physiological fluid shear stress on cells

by on 9 June 2015in Biology & Biotechnology No comment

The response of microbes to changes in the mechanical force of fluid shear has important implications for pathogens, which experience wide fluctuations in fluid shear in vivo during infection. However, the majority of studies have not cultured microbes under physiological fluid shear conditions within a range commonly encountered by microbes during host-pathogen interactions. Here we describe a convenient batch culture biosystem in which (i) the levels of fluid shear force can be varied within physiologically relevant ranges and quantified via mathematical models and (ii) large numbers of cells can be planktonically grown and harvested to examine the effect of fluid shear levels on microbial genomic and phenotypic responses. A quantitative model based on numerical simulations and in situ imaging analysis was developed to calculate the fluid shear imparted by spherical beads of different sizes on bacterial cell cultures grown in a rotating wall vessel (RWV) bioreactor. To demonstrate the application of this model, we subjected cultures of the bacterial pathogen Salmonella enterica serovar Typhimurium to three physiologically-relevant fluid shear ranges during growth in the RVW and demonstrated a progressive relationship between the applied fluid shear and the bacterial genetic and phenotypic responses. By applying this model to different cell types, including other bacterial pathogens, entire classes of genes and proteins involved in cellular interactions may be discovered that have not previously been identified during growth under conventional culture conditions, leading to new targets for vaccine and therapeutic development.

Related URLs:
http://www.ncbi.nlm.nih.gov/pubmed/17142365