Survivability of microorganisms on synthetic and semi-synthetic textile materials used in the production of special purpose clothing in various humidity and temperature conditions.

Effect of electrical charges on potential of fibers for transport of microbial particles in dry and humid air

Different methods available for size measurements of fungal and actinomycete spores were compared for four fungal species ( Penicillium brevicompactum, Penicillium melinii, Cladosporium cladosporioides , and Aspergillus versicolor ) and two actinomycete species ( Streptomyces albus and Thermoactinomyces vulgaris ). The physical size of spores was measured with three microscopic methods: with an optical microscope from stained (wet) slides, with an optical microscope from unstained (dry) slides and with an environmental scanning electron microscope (SEM) directly from the microbial culture. The aerodynamic diameter, d a , of airborne spores was measured with an aerodynamic particle sizer. The respiratory deposition of spores was calculated with a computer-based model. The environmental SEM measurements indicated larger size for fungal spores than the optical microscope, whereas for actinomycete spores, both microscopes gave comparable results. Optical microscopic measurements showed that the stained fungal spores were 1.1-1.2 times larger than the unstained ones, which was attributed to the different hydration status of spores. There was no clear trend in the relationship between the d a and the physical diameter measured with any of three tested microscopic methods. For example, the physical diameter of Cladosporium cladosporioides spores was larger than the d a by a factor ranging from 2.0 to 2.2, whereas the d a of Streptomyces albus spores was larger than the physical diameter by a factor of 1.3-1.5. Thus, the aerodynamic diameter of microbial spores cannot be accurately estimated solely based on the physical diameter but needs information on the density of the spores that may vary considerably. The results on the spore size were utilized to calculate respiratory deposition of spores. The errors in the size measurement were found to result in overestimation of the respiratory deposition of C. cladosporioides spores by a factor of 1.2-1.8, and underestimation of the respiratory deposition of S. albus spores by a factor of 0.6-0.7. These errors in the size measurement cause bias in the exposure assessment and in the estimation of the efficiency of control devices. More research is needed to standardize the method for particle diameter estimates applicable for airborne spores.

Performance of three devices used for the total enumeration of airborne spores-the Air-O-Cell sampling cassette, the Burkard personal volumetric air sampler, and the Button Aerosol Sampler--was evaluated under controlled laboratory conditions. The first two are glass-slide impactors; the third collects spores on a filter. The samplers were challenged with 0.44-5.10 microm polystyrene latex particles and five microorganisms of 0.84-3.07 microm mean aerodynamic diameter: Streptomyces albus, Bacillus subtilis, Cladosporium cladosporioides, Penicillium brevicompactum, and Penicillium melinii. An optical particle counter measured the particle concentrations upstream and downstream of each sampler, and thus determined the physical collection efficiency of the three samplers. Collection efficiency of the Button Aerosol Sampler was close to 100% for the entire particle size range studied. The cut-off size of each impactor was 2.3-2.4 microm. Acridine orange (with epifluorescent microscopy) and lactophenol cotton blue (with bright light microscopy) staining techniques were used for the microscopic enumeration of spores. No significant difference in microscopic counts was found (at the 95% significance level) when using these two techniques with the Button Aerosol Sampler filters. When the lactophenol cotton blue staining was used to compare total microbial counts yielded by all three samplers, the Button Sampler showed significantly higher counts for the smaller size microorganisms (B. subtilis and C. cladosporioides). For the larger microorganisms (P. brevicompactum and P. melinii) all three samplers yielded similar results. Uniformity of particle deposition on the collection surface was highest for the Button Aerosol Sampler due to the design of its inlet. Thus, the filter collection method used with the Button Aerosol Sampler is suitable and can be advantageous for the enumeration of total airborne spores.

Bioaerosols are common biological factors in work environments, which require routine use of filtering respiratory protective devices (FRPDs). Currently, no studies link humidity changes in the filter materials of such devices, during use, with microorganism survivability. Our aim was to determine the microclimate inside FRPDs, by simulating breathing, and to evaluate microorganism survivability under varying humidity conditions. Breathing was simulated using commercial filtering facepiece respirators in a model system. Polypropylene melt-blown nonwoven fabrics with moisture contents of 40%, 80%, and 200%, were used for assessment of microorganisms survivability. A modified AATCC 100-2004 method was used to measure the survivability of ATCC and NCAIM microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger. During simulation relative humidity under the facepiece increased after 7 min of usage to 84%–92% and temperature increased to 29–30 °C. S. aureus survived the best on filter materials with 40%–200% moisture content. A decrease in survivability was observed for E. coli and C. albicans when mass humidity decreased. We found that B. subtilis and A. niger proliferated for 48–72 h of incubation and then died regardless of the moisture content. In conclusion, our tests showed that the survivability of microorganisms on filter materials depends on the amount of accumulated moisture and microorganism type.

We recently developed an electrostatic precipitator with superhydrophobic surface (EPSS), which collects particles into a 10- to 40-μl water droplet allowing achievement of very high concentration rates (defined as the ratio of particle concentration in the collection liquid vs. the airborne particle concentration per time unit) when sampling airborne bacteria. Here, we analyzed the performance of this sampler when collecting three commonly found fungal spores--Cladosporium cladosporioides, Penicillium melinii, and Aspergillus versicolor--under different operating conditions. We also adapted adenosine triphosphate (ATP)-based bioluminescence for the analysis of collection efficiency and the concentration rates. The collection efficiency ranged from 10 to 36% at a sampling flow rate of 10 l/min when the airborne fungal spore concentration was approximately 10(5)-10(6) spores/m(3) resulting in concentration rates in the range of 1 × 10(5)-3 × 10(5)/min for a 10-μl droplet. The collection efficiency was inversely proportional to the airborne spore concentration and it increased to above 60% for common ambient spore concentrations, e.g., 10(4)-10(5) spores/m(3). The spore concentrations determined by the ATP-based method were not statistically different from those determined by microscopy and allowed us to analyze spore concentrations that were too low to be reliably detected by microscopy. The new electrostatic precipitator with superhydrophobic surface (EPSS) collects airborne fungal spores into small water droplets (10 and 40 μl) allowing achievement of concentration rates that are higher than those of most currently available bioaerosol samplers. Biosamplers with high concentration rates enable detection of low ambient aerial bioaerosol concentrations in various environments, including indoors air, and would be useful for improved exposure assessment. A successful adaptation of the adenosine triphosphate (ATP)-based bioluminescence assay for the quantification of fungal spores from a specific species enables fast sample analysis in laboratory investigations. This rapid assay could be especially useful when investigating the performance of biological samplers as a function of multiple operational parameters.

Two-component signal transduction systems (TCSs) play a major role in adaption and survival of microorganisms in a dynamic and sometimes dangerous environment. YycFG is an essential TCS for many Gram-positive bacteria, such as Bacillus subtilis, which regulates many important biological processes. However, its functional essentiality remains largely unknown. Here, we report several YycFG interacting proteins through coimmunoprecipitation (Co-IP) and mass spectrometry (MS) analyses. We engineered the B. subtilis genome by a knock-in approach to express YycG with a C-terminal Flag and YycF with an N-terminal HA tag. Immunoprecipitated fractions using anti-Flag or anti-HA agarose were subjected to MS analyses. A total of 41 YycG interacting proteins and four YycF interacting proteins were identified, most of which are involved in cellular metabolic processes, including cell wall synthesis and modification. The interactions of YycG with AsnB and FabL, as examples, were further validated in vitro. This study provided a clue that YycFG may be directly involved in regulation of bacterial central metabolic pathways.

Isolation of some pathogenic fungi from indoor environment that may cause diseases to athletes was the goal of this work. The effect of different cloth materials and some environmental factors on the growth and adhesion of the isolated fungi as Aspergillus sydowii, Cochliobolus hawaiiensis, Cochliobolus lunatus, Epicoccum nigrum, Nigrospora oryzae, Penicillium aurantiogriseum, Cladosporium sphaerospermum, Aspergillus niger, Cochliobolus australiensis, Stemphylium botryosum, Alternaria. alternata, Fusarium chlamydosporum, Aspergillus flavus and Aspergillus versicolor was investigated. By studying the effect of different cloth materials, at temperatures (18, 25 and 35°C) and at pH values (4, 5.6, 8), it was concluded that cloth material, 74% cotton - 25% polyester- 1% elasthan (C.P.E) was the lowest in susceptibility to fungal attack. The fungal pathogens growth was favored at 35°C and pH 8 after two days of incubation while, after five days the growth was favored at 25 and 35°C at pH 5.6 and pH 8. Alter. alternata and A. flavus were selected for studying their spore adhesion on different cloth material samples. Also, their sensitivity for detergents and drugs on different cloth material samples was carried out. Key words : Pathogenic fungi, athletes, fungal adhesion, antimicrobial activity.

Spores of Bacillus subtilis, conidia of Aspergillus niger, versicolor and ochraceus and cells of Deinococcus radiodurans have been exposed in the dark at two locations (at about 23 degrees S and 24 degrees S) in the Atacama Desert for up to 15 months. B. subtilis spores (survival approximately 15%) and A. niger conidia (survival approximately 30%) outlived the other species. The survival of the conidia and spores species was only slightly poorer than that of the corresponding laboratory controls. However, the Deinococcus radiodurans cells did not survive the desert exposure, because they are readily inactivated at relative humidities between 40 and 80% which typically occur during desert nights. Cellular monolayers of the dry spores and conidia have in addition been exposed to the full sun light for up to several hours. The solar fluences causing 63% loss in viability (F37-values) have been determined. These F37-values are compared with those determined at other global locations such as Punta Arenas (53 degrees S), Key Largo (25 degrees N) or Mainz (50 degrees N) during the same season. The solar UVB radiation kills even the most resistant microorganisms within a few hours due to DNA damages. The data are also discussed with respect to possible similarities between the climatic conditions of the recent Atacama Desert and the deserts of early Mars.

While several methods are available for bioaerosol monitoring, impaction remains the most common one, particularly for collecting fungal spores. Earlier studies have shown that the collection efficiency of many conventional single-stage bioaerosol impactors falls below 50% for spores with an aerodynamic diameter between 1.7 and 2.5 microm because their cut-off size is 2.5 microm or greater. The cut-off size reduction is primarily done by substantially increasing the sampling flow rate or decreasing the impaction jet size, W, to a fraction of a millimetre, with both measures often impractical to implement. Some success has recently been reported on the utilization of an ultra-low jet-to-plate distance, S (S/W < 0.1), in circular impactors. This paper describes a laboratory evaluation and some field testing of two single-stage, single-nozzle, slit bioaerosol impactors, Allergenco-D and Air-O-Cell, which feature the same jet dimensions and flow rate but have some design configuration differences that were initially thought to be of low significance. The collection efficiency and the spore deposit characteristics were determined in the laboratory using real-time aerosol spectrometry and different microscopic enumeration methods as the test impactors were challenged with the non-biological polydisperse NaCl aerosol and the aerosolized fungal spores of Cladosporium cladosporioides, Aspergillus versicolor, and Penicillium melinii. The tests showed that a relatively small reduction in the jet-to-plate distance of a single-stage, single-nozzle impactor with a tapered inlet nozzle, combined with adding a straight section of sufficient length, can significantly decrease the cut-off size to the level that is sufficient to efficiently collect spores of all fungal species. Furthermore, it appears that the slit jet design may improve the application of partial spore counting methodologies with respect to those applied to circular deposits. Data from a demonstration field study, conducted with the two samplers in environments containing a variety of fungal species, supported the laboratory findings.

The exploration of Mars is one of the main objectives of space missions since the red planet is considered to be, or was in the past, potentially habitable. Although the surface of Mars is now dry and arid, abundant research suggests that water covered Mars billions of years ago. Recently, the existence of liquid water in subglacial lakes has been postulated below the South pole of Mars. Until now, experiments have been carried out on the survival of microorganisms in Martian surface conditions, but it remains unknown how their adaptation mechanisms would be in the Martian cryosphere. In this work, two bacterial species (Bacillus subtilis and Curtobacterium flacumfaciens) were subjected to a simulated Martian environment during 24 h using a planetary chamber. Afterward, the molecular machinery of both species was studied to investigate how they had been modified. Proteomes, the entire set of proteins expressed by each bacterium under Earth (named standard) conditions and Martian conditions, were compared using proteomic techniques. To establish this evaluation, both the expression levels of each protein, and the variation in their distribution within the different functional categories were considered. The results showed that these bacterial species followed a different strategy. The Bacillus subtilis resistance approach consisted of improving its stress response, membrane bioenergetics, degradation of biomolecules; and to a lesser extent, increasing its mobility and the formation of biofilms or resistance endospores. On the contrary, enduring strategy of Curtobacterium flacumfaciens comprised of strengthening the cell envelope, trying to protect cells from the extracellular environment. These results are especially important due to their implications for planetary protection, missions to Mars and sample return since contamination by microorganisms would invalidate the results of these investigations.

IntroductionInterest in the icy moons of our Solar System has grown since the discovery of liquid water oceans underneath their surface. Of particular interest is Europa, which is the target of two upcoming missions (Europa Clipper, NASA and JUICE, ESA). Geochemical models suggest the conditions in the sub-surface oceans are habitable and brine veins may exist within the surface ice, which may mediate the transport of microorganisms between the ice shell, water reservoirs and the subsurface ocean [1,2]. The brines are thought to occur during freezing of Europa&amp;#8217;s ocean, mineral precipitates can occur as ice crystals form and absorb water as the ice grains grow.Recent observations of Europa&amp;#8217;s newly disrupted geological regions, such as chaos terrains, suggest a predominance of sodium and magnesium chloride salts [3,4]. Models of the freezing of Europa&amp;#8217;s ocean result in MgCl2 (a chaotropic agent) dominated brine veins in the ice shell, from different starting compositions, and in some cases, even sulfate-rich oceans [5]. &amp;#160;These cold and concentrated MgCl2 brines are likely to be the closest remnants of liquid water to the surface of the ocean of Europa. Solutions of MgCl2 can reach eutectic temperatures of -33&amp;#176;C expanding the regions of habitability in the ice shell into colder regimes. The aim of this study was to investigate the effect of simulated Europa brines (0&amp;#730;C to 33&amp;#730;C, 0.1&amp;#160;MPa to 300&amp;#160;MPa of pressure) on microbial survival and growth.MethodsIn ongoing experiments, microorganisms isolated from extreme environments (Planococcus halocryophilus, Sphingopyxis alaskensis, Halobacillus basquensis and Bacillus subtilis), were exposed to MgCl2 (0 to 3.15 M), temperatures (room temperature, 4&amp;#730;C and -33&amp;#730;C), and pressures (10 to 30&amp;#160;MPa). The microorganisms were grown in a defined medium (based on a modified marine broth recipe), and their growth rates were monitored. New cultures were set up at the maximum tolerated MgCl2 concentrations (approximately 1M). They were then washed at increasing MgCl2 concentrations and incubated at three different temperatures for a week. Microorganisms were washed with a phosphate-buffered saline solution to reduce osmotic shock and plated to measure their survival rate. These experiments were repeated following the same procedure, but in a high-pressure reactor at 10, 20 and 30 MPa.ResultsPreliminary results suggest that certain microorganisms were able to grow at a maximum of 1 M MgCl2. Future work will determine if temperature and/or pressure play a role in the survival rates of microorganisms exposed to MgCl2. These results will help inform the planetary protection requirements for future spacecraft and how terrestrial organisms might interfere with biosignature detection missions to icy moons.&amp;#160;&amp;#160;ReferencesBuffo, J. J., Schmidt, B. E., Huber, C. &amp;amp; Walker, C. C. Entrainment and Dynamics of Ocean&amp;#8208;Derived Impurities Within Europa&amp;#8217;s Ice Shell. J. Geophys. Res. Planets 125, (2020). Buffo, J. J. et al. The Bioburden and Ionic Composition of Hypersaline Lake Ices: Novel Habitats on Earth and Their Astrobiological Implications. Astrobiology 22, 962&amp;#8211;980 (2022). Ligier, N., Poulet, F., Carter, J., Brunetto, R. &amp;amp; Gourgeot, F. VLT/SINFONI Observations of Europa: New Insights into the Surface Composition. Astron. J. 151, 163 (2016). Trumbo, S. K., Brown, M. E. &amp;amp; Hand, K. P. Sodium chloride on the surface of Europa. Sci. Adv. 5, (2019). Fox-Powell, M. G., Wolfenbarger, N. S., Buffo, J. J., Semprich, J. &amp;amp; Ramkissoon, N. K. Modelling possible chemical evolution pathways during freezing of Europa&amp;#8217;s ice shell. in (54th Lunar and Planetary Science Conference 2023, 2023). &amp;#160;

Extracts from many types of plants show several evidences of beneficial health effects in the living system. Calendula officinalis is a well known medicinal plant in our country. The purpose of this study was to examine the effectiveness of C. officinalis for control of growth and survival of microorganisms. Inhibition of growth was tested by the paper disc agar diffusion method. Minimum inhibitory concentration (MIC) was determined by the tube dilution method. C. officinalis leaf extract showed inhibition (MIC, inhibitory) to Escherichia coli, Klebsiella pneumoniae, and Bacillus subtilis and to the other bacteria tested. Antimicrobial effects of leaf extract of C. officinalis on some microorganisms including pathogens were investigated. The extract of C. officinalis leaf which is prepared in was tested on bacterial cultures such as B. subtilis, S. lutea, E. coli, K. pneumoniae and also investigated that minimum inhibitory concentration 4µg/ml of leaf extract of C. officinalis in Petroleum ether against K. pneumoniae and largest inhibitory zone are created by 512mg/ml chloroform extract against E. coli leaf extract of C. officinalis in Petroleum ether has proved better for antibacterial activity. This study demonstrates that the potentiality of C. officinalis as a source of antimicrobials that could be harness for use in the health care delivery process.

Extracts from many types of plants show several evidences of beneficial health effects in the living system. Calendula officinalis is a well known medicinal plant in our country. The purpose of this study was to examine the effectiveness of C. officinalis for control of the growth and survival of microorganisms. The inhibition of growth was tested by the paper disc agar diffusion method. Minimum inhibitory concentration (MIC) was determined by the tube dilution method. C. officinalis leaf extract showed inhibition (MIC, inhibitory) to Escherichia coli, Klebsiella pneumoniae, and Bacillus subtilis and to the other bacteria tested. Antimicrobial effects of leaf extract of C. officinalis on some microorganisms including pathogens were investigated. The extract of C. officinalis leaf which is prepared in was tested on bacterial cultures such as B. subtilis, S. lutea, E. coli, K. pneumoniae and also investigated that minimum inhibitory concentration 4µg/ml of leaf extract of C. officinalis in petroleum ether against K. pneumoniae and largest inhibitory zone are created by 512mg/ml chloroform extract against E. coli leaf extract of C. officinalis in petroleum ether has proved better for antibacterial activity. This study demonstrates that the potentiality of C. officinalis as a source of antimicrobials that could be harness for use in the health care delivery process.

Dried suspensions ofPenicillium roqueforti Thom, Coliphage T-1,Bacillus subtilis and tobacco mosaic virus were exposed to space on board the Gemini-IX-A and XII earth satellites and the Agena-VIII space rocket. All micro-organisms tested survived the direct exposure during the Gemini-IX-A experiment. In the Gemini-XII experiment only the T-1 phage survived the direct exposure. The survival was influenced by the suspending medium and depended on the species of the microorganism. After four months of space flight on the Agena-VIII space rocket surviving fractions between 2×10−3 and 1.0 were found in the unopened flight container. However, micro-organisms exposed on the cover of the container during this period were completely inactivated. Shielding against solar ultraviolet radiation during flight resulted in survival of micro-organisms exceeding to that of the transport controls, and the survival was considered complete.Sterile methylcellulose collection surfaces were exposed to space on board the Gemini-IX-A and XII satellites in an attempt to collect viable micro-organisms in space. None of the collection surfaces yielded viable micro-organisms.

: Microscopia, plating, and bacteriophage analysis techniques were developed for following bacterial survival and bacterial predation in situ in soil. Several new predators were discovered, and their host ranges were studied. The dorminant predators were identified. A new form of competition involving growth initiation factors was discovered. Originator-supplied keywords include: Predation, Spores, Endospores, Growth Initiation, Bacillus subtilus, Bacillus thuringiensis, Ensifer adhaerens, Bacteriophage, Bacterial Competition, Streptomyces, Myxobacteria, Dormacy.