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Sample records for spores carrying temperature-sensitive

  1. Bicarbonate and amino acids are co-germinants for spores of Clostridium perfringens type A isolates carrying plasmid-borne enterotoxin gene.

    Science.gov (United States)

    Alnoman, Maryam; Udompijitkul, Pathima; Banawas, Saeed; Sarker, Mahfuzur R

    2018-02-01

    Clostridium perfringens type A isolates carrying a chromosomal enterotoxin (cpe) gene (C-cpe) are generally linked to food poisoning, while isolates carrying cpe on a plasmid (P-cpe) are associated with non-food-borne gastrointestinal diseases. Both C-cpe and P-cpe isolates can form metabolically dormant spores, which through germination process return to actively growing cells to cause diseases. In our previous study, we showed that only 3 out of 20 amino acids (aa) in phosphate buffer (pH 7.0) triggered germination of spores of P-cpe isolates (P-cpe spores). We now found that 14 out of 20 individual aa tested induced germination of P-cpe spores in the presence of bicarbonate buffer (pH 7.0). However, no significant spore germination was observed with bicarbonate (pH 7.0) alone, indicating that aa and bicarbonate are co-germinants for P-cpe spores. P-cpe strain F4969 gerKC spores did not germinate, and gerAA spores germinated extremely poorly as compared to wild-type and gerKA spores with aa-bicarbonate (pH 7.0) co-germinants. The germination defects in gerKC and gerAA spores were partially restored by complementing gerKC or gerAA spores with wild-type gerKC or gerAA, respectively. Collectively, this study identified aa-bicarbonate as a novel nutrient germinant for P-cpe spores and provided evidence that GerKC and GerAA play major roles in aa-bicarbonate induced germination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Carry

    DEFF Research Database (Denmark)

    Koijen, Ralph S.J.; Moskowitz, Tobias J.; Heje Pedersen, Lasse

    that include global equities, global bonds, currencies, commodities, US Treasuries, credit, and equity index options. This predictability underlies the strong returns to "carry trades" that go long high-carry and short low-carry securities, applied almost exclusively to currencies, but shown here...

  3. Carry

    DEFF Research Database (Denmark)

    Koijen, Ralph S.J.; Moskowitz, Tobias; Pedersen, Lasse Heje

    2018-01-01

    -sectionally and in time series for a host of different asset classes, including global equities, global bonds, commodities, US Treasuries, credit, and options. Carry is not explained by known predictors of returns from these asset classes, and it captures many of these predictors, providing a unifying framework...... for return predictability. We reject a generalized version of Uncovered Interest Parity and the Expectations Hypothesis in favor of models with varying risk premia, in which carry strategies are commonly exposed to global recession, liquidity, and volatility risks, though none fully explains carry’s premium....

  4. Preparation and Application of Temperature Sensitive Paintings

    Science.gov (United States)

    Li, Chi

    2015-11-01

    Temperature sensitive painting (TSP) is a rapidly developing surface optical measurement technology, which uses temperature sensitive fluorescent probe molecular to obtain the temperature distribution on the surface of the model. Two different types of TSP material are prepared to apply in fluid mechanical experiments. Rhodamine is used as fluorescer and acetone as solvent for the first recipe, while rare earth material as fluorescer and zirconia as solvent for the second recipe. With proper calibration, surface temperature nephogram and temperature gradient nephogram is obtained based on the measured light intensity data, and transition location and heat flux is analyzed. Double layer - multi component TSP measurement technology and more strict calibration will be developed in the near future to get more precise heat flux distribution.

  5. A hot topic: temperature sensitive sodium channelopathies.

    Science.gov (United States)

    Egri, Csilla; Ruben, Peter C

    2012-01-01

    Perturbations to body temperature affect almost all cellular processes and, within certain limits, results in minimal effects on overall physiology. Genetic mutations to ion channels, or channelopathies, can shift the fine homeostatic balance resulting in a decreased threshold to temperature induced disturbances. This review summarizes the functional consequences of currently identified voltage-gated sodium (NaV) channelopathies that lead to disorders with a temperature sensitive phenotype. A comprehensive knowledge of the relationships between genotype and environment is not only important for understanding the etiology of disease, but also for developing safe and effective treatment paradigms.

  6. The experienced temperature sensitivity and regulation survey

    Science.gov (United States)

    Van Someren, Eus J. W.; Dekker, Kim; Te Lindert, Bart H. W.; Benjamins, Jeroen S.; Moens, Sarah; Migliorati, Filippo; Aarts, Emmeke; van der Sluis, Sophie

    2016-01-01

    ABSTRACT Individuals differ in thermosensitivity, thermoregulation, and zones of thermoneutrality and thermal comfort. Whereas temperature sensing and -effectuating processes occur in part unconsciously and autonomic, awareness of temperature and thermal preferences can affect thermoregulatory behavior as well. Quantification of trait-like individual differences of thermal preferences and experienced temperature sensitivity and regulation is therefore relevant to obtain a complete understanding of human thermophysiology. Whereas several scales have been developed to assess instantaneous appreciation of heat and cold exposure, a comprehensive scale dedicated to assess subjectively experienced autonomic or behavioral thermoregulatory activity has been lacking so far. We constructed a survey that specifically approaches these domains from a trait-like perspective, sampled 240 volunteers across a wide age range, and analyzed the emergent component structure. Participants were asked to report their thermal experiences, captured in 102 questions, on a 7-point bi-directional Likert scale. In a second set of 32 questions, participants were asked to indicate the relative strength of experiences across different body locations. Principal component analyses extracted 21 meaningful dimensions, which were sensitive to sex-differences and age-related changes. The questions were also assessed in a matched sample of 240 people with probable insomnia to evaluate the sensitivity of these dimensions to detect group differences in a case-control design. The dimensions showed marked mean differences between cases and controls. The survey thus has discriminatory value. It can freely be used by anyone interested in studying individual or group differences in thermosensitivity and thermoregulation. PMID:27227080

  7. Lyophilized spore dispenser

    Science.gov (United States)

    Jessup, A. D. (Inventor)

    1973-01-01

    A lyophilized spore dispenser is provided which produces a finely divided, monoparticulate cloud of bacterial spores. The spores are contained within a tightly sealed chamber, and a turbulator orifice connected to an air supply source provides a jet of air which stirs up the spores and causes the spores to be suspended in eddy currents within the chamber. This air jet also produces a positive pressure within the chamber which forces the spores out of an injection orifice.

  8. Isolation of temperature-sensitive mutants of 16 S rRNA in Escherichia coli

    DEFF Research Database (Denmark)

    Triman, K; Becker, E; Dammel, C

    1989-01-01

    Temperature-sensitive mutants have been isolated following hydroxylamine mutagenesis of a plasmid containing Escherichia coli rRNA genes carrying selectable markers for spectinomycin resistance (U1192 in 16 S rRNA) and erythromycin resistance (G2058 in 23 S rRNA). These antibiotic resistance...

  9. Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

    Science.gov (United States)

    Bing Song; Shuli Niu; Ruise Luo; Yiqi Luo; Jiquan Chen; Guirui Yu; Janusz Olejnik; Georg Wohlfahrt; Gerard Kiely; Ako Noormets; Leonardo Montagnani; Alessandro Cescatti; Vincenzo Magliulo; Beverly Elizabeth Law; Magnus Lund; Andrej Varlagin; Antonio Raschi; Matthias Peichl; Mats B. Nilsson; Lutz Merbold

    2014-01-01

    Recent studies revealed convergent temperature sensitivity of ecosystem respiration (Re) within aquatic ecosystems and between terrestrial and aquatic ecosystems. We do not know yet whether various terrestrial ecosystems have consistent or divergent temperature sensitivity. Here, we synthesized 163 eddy covariance flux sites across the world and...

  10. Sphagnum moss disperses spores with vortex rings.

    Science.gov (United States)

    Whitaker, Dwight L; Edwards, Joan

    2010-07-23

    Sphagnum spores, which have low terminal velocities, are carried by turbulent wind currents to establish colonies many kilometers away. However, spores that are easily kept aloft are also rapidly decelerated in still air; thus, dispersal range depends strongly on release height. Vascular plants grow tall to lift spores into sufficient wind currents for dispersal, but nonvascular plants such as Sphagnum cannot grow sufficiently high. High-speed videos show that exploding capsules of Sphagnum generate vortex rings to efficiently carry spores high enough to be dispersed by turbulent air currents. Spores launched ballistically at similar speeds through still air would travel a few millimeters and not easily reach turbulent air. Vortex rings are used by animals; here, we report vortex rings generated by plants.

  11. Characterization of the temperature-sensitive mutations un-7 and png-1 in Neurospora crassa.

    Science.gov (United States)

    Dieterle, Michael G; Wiest, Aric E; Plamann, Mike; McCluskey, Kevin

    2010-05-18

    The model filamentous fungus Neurospora crassa has been studied for over fifty years and many temperature-sensitive mutants have been generated. While most of these have been mapped genetically, many remain anonymous. The mutation in the N. crassa temperature-sensitive lethal mutant un-7 was identified by a complementation based approach as being in the open reading frame designated NCU00651 on linkage group I. Other mutations in this gene have been identified that lead to a temperature-sensitive morphological phenotype called png-1. The mutations underlying un-7 result in a serine to phenylalanine change at position 273 and an isoleucine to valine change at position 390, while the mutation in png-1 was found to result in a serine to leucine change at position 279 although there were other conservative changes in this allele. The overall morphology of the strain carrying the un-7 mutation is compared to strains carrying the png-1 mutation and these mutations are evaluated in the context of other temperature-sensitive mutants in Neurospora.

  12. Temperature sensitive surfaces and methods of making same

    Science.gov (United States)

    Liang, Liang [Richland, WA; Rieke, Peter C [Pasco, WA; Alford, Kentin L [Pasco, WA

    2002-09-10

    Poly-n-isopropylacrylamide surface coatings demonstrate the useful property of being able to switch charateristics depending upon temperature. More specifically, these coatings switch from being hydrophilic at low temperature to hydrophobic at high temperature. Research has been conducted for many years to better characterize and control the properties of temperature sensitive coatings. The present invention provides novel temperature sensitive coatings on articles and novel methods of making temperature sensitive coatings that are disposed on the surfaces of various articles. These novel coatings contain the reaction products of n-isopropylacrylamide and are characterized by their properties such as advancing contact angles. Numerous other characteristics such as coating thickness, surface roughness, and hydrophilic-to-hydrophobic transition temperatures are also described. The present invention includes articles having temperature-sensitve coatings with improved properties as well as improved methods for forming temperature sensitive coatings.

  13. Targeted drug delivery using temperature-sensitive liposomes

    International Nuclear Information System (INIS)

    Magin, R.L.; Niesman, M.R.

    1984-01-01

    Liposomes are receiving considerable attention as vehicles for selective drug delivery. One method of targeting liposomal contents involves the combination of local hyperthermia with temperature-sensitive liposomes. Such liposomes have been used to increase the uptake of methotrexate and cis-platinum into locally heated mouse tumors. However, additional information is needed on the mechanism of liposome drug release and the physiologic deposition of liposomes in vivo before clinical trails are begun. Current research is directed at studying the encapsulation and release of water soluble drugs from temperature-sensitive liposomes. The influence of liposome size, structure, and composition on the rapid release in plasma of cytosine arabinoside, cis-platinum, and the radiation sensitizer SR-2508 are described. These results demonstrate potential applications for temperature-sensitive liposomes in selective drug delivery

  14. Fiber Fabry-Perot interferometer with controllable temperature sensitivity.

    Science.gov (United States)

    Zhang, Xinpu; Peng, Wei; Zhang, Yang

    2015-12-01

    We proposed a fiber taper based on the Fabry-Perot (FP) interferometer structure with controllable temperature sensitivity. The FP interferometer is formed by inserting a segment of tapered fiber tip into the capillary and subsequently splicing the other end of the capillary to a single-mode fiber (SMF), the tapered fiber endface, and the spliced face form the FP cavity. Through controlling the inserted tapered fiber length, a series of FP interferometers were made. Because the inserted taper tip has the degree of freedom along the fiber axial, when the FP interferometer is subjected to temperature variation, the thermal expansion of the fiber taper tip will resist the FP cavity length change caused by the evolution of capillary length, and we can control the temperature sensitivity by adjusting the inserted taper length. In this structure, the equivalent thermal expansion coefficient of the FP interferometer can be defined; it was used to evaluate the temperature sensitivity of the FP interferometer, which provides an effective method to eliminate the temperature effect and to enhance other measurement accuracy. We fabricated the FP interferometers and calibrated their temperature characters by measuring the wavelength shift of the resonance dips in the reflection spectrum. In a temperature range of 50°C to 150°C, the corresponding temperature sensitivities can be controlled between 0 and 1.97 pm/°C when the inserted taper is between 75 and 160 μm. Because of its controllable temperature sensitivity, ease of fabrication, and low cost, this FP interferometer can meet different temperature sensitivity requirements in various application areas, especially in the fields which need temperature insensitivity.

  15. Magnetocaloric effect in temperature-sensitive magnetic fluids

    Indian Academy of Sciences (India)

    The magnetocaloric properties of three different temperature-sensitive magnetic fluids were studied. The pyromagnetic coefficient for all the materials were obtained and it was found that this property depends on physical and magnetic properties like size, magnetization and Curie temperature. A theoretical model was ...

  16. Dopamine modulates metabolic rate and temperature sensitivity in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Taro Ueno

    Full Text Available Homeothermal animals, such as mammals, maintain their body temperature by heat generation and heat dissipation, while poikilothermal animals, such as insects, accomplish it by relocating to an environment of their favored temperature. Catecholamines are known to regulate thermogenesis and metabolic rate in mammals, but their roles in other animals are poorly understood. The fruit fly, Drosophila melanogaster, has been used as a model system for the genetic studies of temperature preference behavior. Here, we demonstrate that metabolic rate and temperature sensitivity of some temperature sensitive behaviors are regulated by dopamine in Drosophila. Temperature-sensitive molecules like dTrpA1 and shi(ts induce temperature-dependent behavioral changes, and the temperature at which the changes are induced were lowered in the dopamine transporter-defective mutant, fumin. The mutant also displays a preference for lower temperatures. This thermophobic phenotype was rescued by the genetic recovery of the dopamine transporter in dopamine neurons. Flies fed with a dopamine biosynthesis inhibitor (3-iodo-L-tyrosine, which diminishes dopamine signaling, exhibited preference for a higher temperature. Furthermore, we found that the metabolic rate is up-regulated in the fumin mutant. Taken together, dopamine has functions in the temperature sensitivity of behavioral changes and metabolic rate regulation in Drosophila, as well as its previously reported functions in arousal/sleep regulation.

  17. Watershed geomorphology modifies the temperature sensitivity of aquatic ecosystem metabolism

    Science.gov (United States)

    Jankowski, K. J.; Schindler, D.

    2015-12-01

    How carbon cycles are regulated by temperature remains a substantial uncertainty in our understanding of how watersheds will respond to ongoing climate change. Aquatic ecosystems are significant components of carbon flux to the atmosphere and ocean, yet we have limited understanding of how changing thermal regimes will alter rates of ecosystem metabolic processes, and, therefore, aquatic contributions to carbon cycles at watershed to global scales. Watershed geomorphology controls the landscape-scale distribution of organic material that can form the metabolic base of aquatic ecosystems, which will likely affect the temperature sensitivity of aquatic ecosystem metabolism. Across 23 streams in a boreal river basin, we estimated how temperature sensitivity of ecosystem respiration (ER), an important component of the aquatic C cycle, varied among streams with different watershed characteristics. We found that geomorphic conditions imposed strong ultimate controls on temperature sensitivity: ER in streams draining flat watersheds was much more sensitive to temperature than streams draining steeper watersheds. Further, we show that the link between watershed geomorphology and temperature sensitivity was related to changes in the quality of carbon substrates across the gradient in watershed slope. These results suggest that geomorphic conditions will ultimately control how carbon processing responds to warming climate, thereby affecting carbon transport and storage, and likely food web responses, in river networks.

  18. Temperature sensitivity of the oxygenation reaction of stripped ...

    African Journals Online (AJOL)

    Temperature sensitivity of the oxygenation reaction of stripped haemolysates from the freshwater fishes Labeo capensis and Ciarias gariepinus. ... of the mudfish Labeo capensis and the catfish Clarias gariepinus, stripped by gel filtration chromatography and buffered at 23°C in 0,05 M Hepes (pH 7,48), were determined at ...

  19. Magnetocaloric effect in temperature-sensitive magnetic fluids

    Indian Academy of Sciences (India)

    Unknown

    magnetization, heat capacity of the material and carrier liquid. In this paper, we report the magnetocaloric pro- perties of certain temperature-sensitive magnetic fluids. Here, an indirect measurement technique to determine the change in entropy using temperature-dependent magnetic property of magnetic fluid, is reported.

  20. Temperature sensitivity of respiration scales with organic matter recalcitrance

    Science.gov (United States)

    Craine, J. M.; Fierer, N.; McLauchlan, K. K.

    2010-12-01

    Microbial decomposition of soil organic matter is a key process in determining the carbon sequestration potential of ecosystems and carbon fluxes to the atmosphere. Since microbial decomposition is highly sensitive to short-term changes in temperature, predicting the temperature sensitivity of microbial decomposition is critical to predicting future atmospheric carbon dioxide concentrations and feedbacks to anthropogenic warming. Fundamental principles of enzyme kinetics, embodied in the carbon-quality temperature hypothesis, predict that the temperature sensitivity of microbial decomposition should increase with increasing biochemical recalcitrance of a substrate. To test the generality of this principle, we measured the temperature sensitivity of microbial respiration of soil organic matter with serial short-term temperature manipulations over 365 days for 28 North American soils. When joined with data from similar studies that represent a wide variety of contrasts, we show that the temperature sensitivity of organic matter decomposition scales with biochemical recalcitrance. With physico-chemical protection likely an important covariate for relating plant and soil organic matter decomposition scalars, biochemically recalcitrant organic matter is highly susceptible to short-term increases in temperature, a key link in predicting the effects of warming on carbon cycling.

  1. Temperature sensitive riboflavin mutants of Penicillium vermiculatum Dangeard

    International Nuclear Information System (INIS)

    Mitra, J.; Chaudhari, K.L.

    1974-01-01

    Two temperature sensitive UV induced riboflavin mutants rib 1 and rib 6 have been physiologically and genetically characterized. The two mutants behave differently with regard to their temperature sensitivity. The rib 1 mutant exhibits a leaky growth in minimal medium between 15 0 C and 30 0 C but grows well when the medium is supplemented with riboflavin. At 35 0 C the growth response of the mutant is at its max. and at 40 0 C and below 15 0 C it ceases to grow. The rib 6 mutant which is red brown in colour shows wild type character at temp. below 25 0 C in minimal medium but requires riboflavin at 30 0 C and above. Heterokaryotic analysis revealed the nonallelic nature of the two temperature mutants. Genetic tests of allelic relationship between riboflavin markers by crossing were also done. (author)

  2. Temperature-sensitive glutamate dehydrogenase mutants of Salmonella typhimurium.

    OpenAIRE

    Dendinger, S M; Brenchley, J E

    1980-01-01

    Mutants of Salmonella typhimurium defective in glutamate dehydrogenase activity were isolated in parent strains lacking glutamate synthase activity by localizcd mutagenesis or by a general mutagenesis combined with a cycloserine enrichment for glutamate auxotrophs. Two mutants with temperature-sensitive phenotypes had glutamate dehydrogenase activities that were more thermolabile than that of an isogenic control strain. Eight other mutants had less than 10% of the wild-type glutamate dehydrog...

  3. Rapid onsite assessment of spore viability.

    Energy Technology Data Exchange (ETDEWEB)

    Branda, Steven; Lane, Todd W.; VanderNoot, Victoria A.; Gaucher, Sara P.; Jokerst, Amanda S.

    2005-12-01

    This one year LDRD addresses problems of threat assessment and restoration of facilities following a bioterror incident like the incident that closed down mail facilities in late 2001. Facilities that are contaminated with pathogenic spores such as B. anthracis spores must be shut down while they are treated with a sporicidal agent and the effectiveness of the treatment is ascertained. This process involves measuring the viability of spore test strips, laid out in a grid throughout the facility; the CDC accepted methodologies require transporting the samples to a laboratory and carrying out a 48 hr outgrowth experiment. We proposed developing a technique that will ultimately lead to a fieldable microfluidic device that can rapidly assess (ideally less than 30 min) spore viability and effectiveness of sporicidal treatment, returning facilities to use in hours not days. The proposed method will determine viability of spores by detecting early protein synthesis after chemical germination. During this year, we established the feasibility of this approach and gathered preliminary results that should fuel a future more comprehensive effort. Such a proposal is currently under review with the NIH. Proteomic signatures of Bacillus spores and vegetative cells were assessed by both slab gel electrophoresis as well as microchip based gel electrophoresis employing sensitive laser-induced fluorescence detection. The conditions for germination using a number of chemical germinants were evaluated and optimized and the time course of protein synthesis was ascertained. Microseparations were carried out using both viable spores and spores inactivated by two different methods. A select number of the early synthesis proteins were digested into peptides for analysis by mass spectrometry.

  4. Greater temperature sensitivity of plant phenology at colder sites

    DEFF Research Database (Denmark)

    Prevéy, Janet; Vellend, Mark; Rüger, Nadja

    2017-01-01

    Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance...... warmer high-latitude locations. A similar pattern was seen over time for the flowering phenology of a widespread species, Cassiope tetragona. These are among the first results highlighting differential phenological responses of plants across a climatic gradient and suggest the possibility of convergence...

  5. Water Recycling removal using temperature-sensitive hydronen

    Energy Technology Data Exchange (ETDEWEB)

    Rana B. Gupta

    2002-10-30

    The overall objective of this project was to study the proposed Water Recycling/Removal Using Temperature-Sensitive Hydrogels. The main element of this technology is the design of a suitable hydrogel that can perform needed water separation for pulp and paper industry. The specific topics studied are to answer following questions: (a) Can water be removed using hydrogel from large molecules such as lignin? (b) Can the rate of separation be made faster? (c) What are the molecular interactions with hydrogel surface? (d) Can a hydrogel be designed for a high ionic strength and high temperature? Summary of the specific results are given.

  6. Phosphorescence In Bacillus Spores

    National Research Council Canada - National Science Library

    Reinisch, Lou; Swartz, Barry A; Bronk, Burt V

    2003-01-01

    .... Our present work attempts to build on this approach for environmental applications. We have measured a change in the fluorescence spectra of suspensions of Bacillus bacteria between the vegetative bacteria and their spores at room temperature...

  7. Temperature sensitivity of organic compound destruction in SCWO process.

    Science.gov (United States)

    Tan, Yaqin; Shen, Zhemin; Guo, Weimin; Ouyang, Chuang; Jia, Jinping; Jiang, Weili; Zhou, Haiyun

    2014-03-01

    To study the temperature sensitivity of the destruction of organic compounds in supercritical water oxidation process (SCWO), oxidation effects of twelve chemicals in supercritical water were investigated. The SCWO reaction rates of different compounds improved to varying degrees with the increase of temperature, so the highest slope of the temperature-effect curve (imax) was defined as the maximum ratio of removal ratio to working temperature. It is an important index to stand for the temperature sensitivity effect in SCWO. It was proven that the higher imax is, the more significant the effect of temperature on the SCWO effect is. Since the high-temperature area of SCWO equipment is subject to considerable damage from fatigue, the temperature is of great significance in SCWO equipment operation. Generally, most compounds (imax > 0.25) can be completely oxidized when the reactor temperature reaches 500°C. However, some compounds (imax > 0.25) need a higher temperature for complete oxidation, up to 560°C. To analyze the correlation coefficients between imax and various molecular descriptors, a quantum chemical method was used in this study. The structures of the twelve organic compounds were optimized by the Density Functional Theory B3LYP/6-311G method, as well as their quantum properties. It was shown that six molecular descriptors were negatively correlated to imax while other three descriptors were positively correlated to imax. Among them, dipole moment had the greatest effect on the oxidation thermodynamics of the twelve organic compounds. Once a correlation between molecular descriptors and imax is established, SCWO can be run at an appropriate temperature according to molecular structure. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  8. Glucose- and temperature-sensitive nanoparticles for insulin delivery

    Directory of Open Access Journals (Sweden)

    Wu JZ

    2017-05-01

    Full Text Available Jun-Zi Wu,1 Gareth R Williams,2 He-Yu Li,1 Dongxiu Wang,3 Huanling Wu,1 Shu-De Li,4 Li-Min Zhu1 1College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China; 2UCL School of Pharmacy, University College London, London, UK; 3Central Laboratory, Environmental Monitoring Center of Kunming, 4School of Basic Medical Sciences, Kunming Medical University, Kunming, People’s Republic of China Abstract: Glucose- and temperature-sensitive polymers of a phenylboronic acid derivative and diethylene glycol dimethacrylate (poly(3-acrylamidophenyl boronic acid-b-diethylene glycol methyl ether methacrylate; p(AAPBA-b-DEGMA were prepared by reversible addition–fragmentation chain transfer polymerization. Successful polymerization was evidenced by 1H nuclear magnetic resonance and infrared spectroscopy, and the polymers were further explored in terms of their glass transition temperatures and by gel permeation chromatography (GPC. The materials were found to be temperature sensitive, with lower critical solution temperatures in the region of 12°C–47°C depending on the monomer ratio used for reaction. The polymers could be self-assembled into nanoparticles (NPs, and the zeta potential and size of these particles were determined as a function of temperature and glucose concentration. Subsequently, the optimum NP formulation was loaded with insulin, and the drug release was studied. We found that insulin was easily encapsulated into the p(AAPBA-b-DEGMA NPs, with a loading capacity of ~15% and encapsulation efficiency of ~70%. Insulin release could be regulated by changes in temperature and glucose concentration. Furthermore, the NPs were non-toxic both in vitro and in vivo. Finally, the efficacy of the formulations at managing blood glucose levels in a murine hyperglycemic diabetes model was studied. The insulin-loaded NPs could reduce blood glucose levels over an extended period of 48 h. Since they

  9. Fifth international fungus spore conference

    Energy Technology Data Exchange (ETDEWEB)

    Timberlake, W.E.

    1993-04-01

    This folio contains the proceedings of the Fifth International Fungal Spore Conference held August 17-21, 1991 at the Unicoi State Park at Helen, Georgia. The volume contains abstracts of each oral presentation as well as a collection of abstracts describing the poster sessions. Presentations were organized around the themes (1) Induction of Sporulation, (2) Nuclear Division, (3) Spore Formation, (4) Spore Release and Dispersal, and (4) Spore Germination.

  10. Temperature Sensitive Particle for Velocity and Temperature Measurement.

    Science.gov (United States)

    Someya, Satoshi; Okamoto, Koji; Iida, Masao

    2007-11-01

    Phosphorescence and fluorescence are often applied to measure the temperature and the concentration of oxygen. The intensity and the lifetime of phosphor depend on the temperature and the oxygen concentration, due to the quenching effect of the phosphor. The present study clarified the effects of temperature on the lifetime of phosphorescence of Porphyrins, Ru(bpy)3^2+ and the europium complex. The phosphorescence lifetime of oil solution / water solution / painted wall were measured with changing temperature and oxygen concentration. In addition, the optical property of the small particles incorporated with the europium complex was investigated in the oil/water. The lifetime was strongly affected by temperature. Then, the temperature sensitive particle (TSParticle) with metal complex was applied to measure temperature in Silicone oil (10cSt) two-dimensionally. Present study is the result of ?High speed three-dimensional direct measurement technology development for the evaluation of heat flux and flow of liquid metal? entrusted to the University of Tokyo by the Ministry of Education, Culture, Sports, Science and Technology of Japan(MEXT).

  11. Temperature sensitivity of organic-matter decay in tidal marshes

    Science.gov (United States)

    Kirwan, Matthew L.; Guntenspergen, Glenn R.; Langley, J.A.

    2014-01-01

    Approximately half of marine carbon sequestration takes place in coastal wetlands, including tidal marshes, where organic matter contributes to soil elevation and ecosystem persistence in the face of sea-level rise. The long-term viability of marshes and their carbon pools depends, in part, on how the balance between productivity and decay responds to climate change. Here, we report the sensitivity of labile soil organic-matter decay in tidal marshes to seasonal and latitudinal variations in temperature measured over a 3-year period. We find a moderate increase in decay rate at warmer temperatures (3-6% per °C, Q10 = 1.3-1.5). Despite the profound differences between microbial metabolism in wetlands and uplands, our results indicate a strong conservation of temperature sensitivity. Moreover, simple comparisons with organic-matter production suggest that elevated atmospheric CO2 and warmer temperatures will accelerate carbon accumulation in marsh soils, and potentially enhance their ability to survive sea-level rise.

  12. Isolation of temperature-sensitive mutants of 16 S rRNA in Escherichia coli

    DEFF Research Database (Denmark)

    Triman, K; Becker, E; Dammel, C

    1989-01-01

    Temperature-sensitive mutants have been isolated following hydroxylamine mutagenesis of a plasmid containing Escherichia coli rRNA genes carrying selectable markers for spectinomycin resistance (U1192 in 16 S rRNA) and erythromycin resistance (G2058 in 23 S rRNA). These antibiotic resistance...... alleles, originally identified by Morgan and co-workers, enable us to follow expression of cloned rRNA genes in vivo. Recessive mutations causing the loss of expression of the cloned 16 S rRNA gene were identified by the loss of the ability of cells to survive on media containing spectinomycin....... The mutations were localized by in vitro restriction fragment replacement followed by in vivo marker rescue and were identified by DNA sequence analysis. We report here seven single-base alterations in 16 S rRNA (A146, U153, A350, A359, A538, A1292 and U1293), five of which produce temperature...

  13. Further studies on a temperature-sensitive mutant of Escherichia coli with defective repair capacity

    International Nuclear Information System (INIS)

    Morfiadakis, I.; Geissler, E.; Akademie der Wissenschaften der DDR, Berlin. Zentralinstitut fuer Molekularbiologie)

    1981-01-01

    A temperature-sensitive mutant of E. coli, WG24, was studied with respect to its sensitivity to photodynamic action, its capacity to perform host controlled reactivation, and its sensitivity to transduction at elevated temperatures. Mutant cells are much more sensitive than wild type cells to photodynamic action by thiopyronine and visible light at elevated temperatures. As well defined rec mutants, WG24 cells are less able to reactivate UV irradiated lambdac phages at elevated temperatures, while their ability to repair T1 phages is less impaired. Mutant cells cannot be transduced to T6 resistance at a detectable rate at elevated temperature. It is concluded, therefore, that some rec gene carries a ts mutation in this mutant. (author)

  14. Neighborhood properties are important determinants of temperature sensitive mutations.

    Directory of Open Access Journals (Sweden)

    Svetlana Lockwood

    Full Text Available Temperature-sensitive (TS mutants are powerful tools to study gene function in vivo. These mutants exhibit wild-type activity at permissive temperatures and reduced activity at restrictive temperatures. Although random mutagenesis can be used to generate TS mutants, the procedure is laborious and unfeasible in multicellular organisms. Further, the underlying molecular mechanisms of the TS phenotype are poorly understood. To elucidate TS mechanisms, we used a machine learning method-logistic regression-to investigate a large number of sequence and structure features. We developed and tested 133 features, describing properties of either the mutation site or the mutation site neighborhood. We defined three types of neighborhood using sequence distance, Euclidean distance, and topological distance. We discovered that neighborhood features outperformed mutation site features in predicting TS mutations. The most predictive features suggest that TS mutations tend to occur at buried and rigid residues, and are located at conserved protein domains. The environment of a buried residue often determines the overall structural stability of a protein, thus may lead to reversible activity change upon temperature switch. We developed TS prediction models based on logistic regression and the Lasso regularized procedure. Through a ten-fold cross-validation, we obtained the area under the curve of 0.91 for the model using both sequence and structure features. Testing on independent datasets suggested that the model predicted TS mutations with a 50% precision. In summary, our study elucidated the molecular basis of TS mutants and suggested the importance of neighborhood properties in determining TS mutations. We further developed models to predict TS mutations derived from single amino acid substitutions. In this way, TS mutants can be efficiently obtained through experimentally introducing the predicted mutations.

  15. Spore: Spawning Evolutionary Misconceptions?

    Science.gov (United States)

    Bean, Thomas E.; Sinatra, Gale M.; Schrader, P. G.

    2010-10-01

    The use of computer simulations as educational tools may afford the means to develop understanding of evolution as a natural, emergent, and decentralized process. However, special consideration of developmental constraints on learning may be necessary when using these technologies. Specifically, the essentialist (biological forms possess an immutable essence), teleological (assignment of purpose to living things and/or parts of living things that may not be purposeful), and intentionality (assumption that events are caused by an intelligent agent) biases may be reinforced through the use of computer simulations, rather than addressed with instruction. We examine the video game Spore for its depiction of evolutionary content and its potential to reinforce these cognitive biases. In particular, we discuss three pedagogical strategies to mitigate weaknesses of Spore and other computer simulations: directly targeting misconceptions through refutational approaches, targeting specific principles of scientific inquiry, and directly addressing issues related to models as cognitive tools.

  16. Pollen and spore monitoring in the world.

    Science.gov (United States)

    Buters, J T M; Antunes, C; Galveias, A; Bergmann, K C; Thibaudon, M; Galán, C; Schmidt-Weber, C; Oteros, J

    2018-01-01

    Ambient air quality monitoring is a governmental duty that is widely carried out in order to detect non-biological ("chemical") components in ambient air, such as particles of world and to create an interactive visualization of their distribution. The method employed to collect information was based on: (a) a review of the recent and historical bibliography related to pollen and fungal spore monitoring, and (b) personal surveys of the managers of national and regional monitoring networks. The interactive application was developed using the R programming language. We have created an inventory of the active pollen and spore monitoring stations in the world. There are at least 879 active pollen monitoring stations in the world, most of which are in Europe (> 500). The prevalent monitoring method is based on the Hirst principle (> 600 stations). The inventory is visualised as an interactive and on-line map. It can be searched, its appearance can be adjusted to the users' needs and it is updated regularly, as new stations or changes to those that already exist can be submitted online. The map shows the current situation of pollen and spore monitoring and facilitates collaboration among those individuals who are interested in pollen and spore counts. It might also help to improve the monitoring of biological particles up to the current level employed for non-biological components.

  17. Carrying Capacity

    DEFF Research Database (Denmark)

    Schroll, Henning; Andersen, Jan; Kjærgård, Bente

    2012-01-01

    A spatial planning act was introduced inIndonesia 1992 and renewed in 2008. It emphasised the planning role of decentralised authorities. The spatial planning act covers both spatial and environmental issues. It defines the concept of carrying capacity and includes definitions of supportive....../cities. Four different sectors (water, food production, waste, and forests) were selected as core areas for decentralised spatial planning. Indicators for SCC and ACC were identified and assessed with regard to relevance and quantifiability. For each of the indicators selected, a legal threshold or guiding...... was introduced inIndonesia 1992 and renewed in 2008. It emphasised the planning role of decentralised authorities. The spatial planning act covers both spatial and environmental issues. It defines the concept of carrying capacity and includes definitions of supportive carrying capacity (SCC) and assimilative...

  18. Temperature sensitivity of the penicillin-induced autolysis mechanism in nongrowing cultures of Escherichia coli.

    OpenAIRE

    Kusser, W; Ishiguro, E E

    1987-01-01

    The effect of incubation temperature on the ampicillin-induced autolysis of nongrowing Escherichia coli was determined. The autolysis mechanisms in amino acid-deprived relA mutant cells treated with chloramphenicol were temperature sensitive. This temperature-sensitive autolysis was demonstrated in three independent ways: turbidimetric determinations, viable cell counts, and solubilization of radiolabeled peptidoglycan.

  19. Airborne pollen and fungal spores in Garki, Abuja (North-Central Nigeria)

    OpenAIRE

    Ezike, Dimphna Nneka; Nnamani, Catherine V.; Ogundipe, Oluwatoyin T.; Adekanmbi, Olushola H.

    2016-01-01

    The ambient atmosphere is dominated with pollen and spores, which trigger allergic reactions and diseases and impact negatively on human health. A survey of pollen and fungal spores constituents of the atmosphere of Garki, Abuja (North-Central Nigeria) was carried out for 1?year (June 1, 2011?May 31, 2012). The aim of the study was to determine the prevalence and abundance of pollen and fungal spores in the atmosphere and their relationship with meteorological parameters. Airborne samples wer...

  20. New pressure and temperature effects on bacterial spores

    International Nuclear Information System (INIS)

    Mathys, A; Knorr, D; Heinz, V

    2008-01-01

    The mechanism of inactivation of bacterial spores by heat and pressure is still a matter of discussion. Obviously, the change of the dissociation equilibrium under pressure and temperature plays a dominant role in inactivation of microorganisms. Heat and pressure inactivation of Geobacillus. stearothermophilus spores at different initial pH-values in ACES and phosphate buffer confirmed this view. Thermal inactivation in ACES buffer at 122 deg. C resulted in higher logarithmic reductions. Contrary, after pressure treatment at 900 MPa with 80 deg. C phosphate buffer showed higher inactivation. These results indicated the different dissociation equilibrium shifts in buffer systems by heat and pressure. Due to preparation, storage and handling of highly concentrated spore suspensions the clumping and the formation of aggregates can hardly be avoided. Consequently, the impact of the agglomeration size distribution on the quantitative assessment of G. stearothermophilus spore inactivation was determined by using a three-fold dynamic optical backreflexion measurement. Two limiting cases have been discriminated in mathematical modelling: three dimensional, spherical packing for maximum spore count and two dimensional, circular packing for minimum spore count of a particular agglomerate. Thermal inactivation studies have been carried out in thin glass capillaries, where by using numerical simulations the non isothermal conditions were modelled and taken into account. It is shown that the shoulder formation often found in thermal spore inactivation can sufficiently be described by first-order inactivation kinetics when the agglomeration size is considered. In case of high pressure inactivation agglomerations could be strongly changed by high forces at compression and especially decompression phase. The physiological response of Bacillus licheniformis spores to high pressure was investigated using multiparameter flow cytometry. Spores were treated by high pressure at 150 MPa

  1. New pressure and temperature effects on bacterial spores

    Science.gov (United States)

    Mathys, A.; Heinz, V.; Knorr, D.

    2008-07-01

    The mechanism of inactivation of bacterial spores by heat and pressure is still a matter of discussion. Obviously, the change of the dissociation equilibrium under pressure and temperature plays a dominant role in inactivation of microorganisms. Heat and pressure inactivation of Geobacillus. stearothermophilus spores at different initial pH-values in ACES and phosphate buffer confirmed this view. Thermal inactivation in ACES buffer at 122°C resulted in higher logarithmic reductions. Contrary, after pressure treatment at 900 MPa with 80°C phosphate buffer showed higher inactivation. These results indicated the different dissociation equilibrium shifts in buffer systems by heat and pressure. Due to preparation, storage and handling of highly concentrated spore suspensions the clumping and the formation of aggregates can hardly be avoided. Consequently, the impact of the agglomeration size distribution on the quantitative assessment of G. stearothermophilus spore inactivation was determined by using a three-fold dynamic optical backreflexion measurement. Two limiting cases have been discriminated in mathematical modelling: three dimensional, spherical packing for maximum spore count and two dimensional, circular packing for minimum spore count of a particular agglomerate. Thermal inactivation studies have been carried out in thin glass capillaries, where by using numerical simulations the non isothermal conditions were modelled and taken into account. It is shown that the shoulder formation often found in thermal spore inactivation can sufficiently be described by first-order inactivation kinetics when the agglomeration size is considered. In case of high pressure inactivation agglomerations could be strongly changed by high forces at compression and especially decompression phase. The physiological response of Bacillus licheniformis spores to high pressure was investigated using multiparameter flow cytometry. Spores were treated by high pressure at 150 MPa with 37

  2. New pressure and temperature effects on bacterial spores

    Energy Technology Data Exchange (ETDEWEB)

    Mathys, A; Knorr, D [Berlin University of Technology, Department of Food Biotechnology and Food Process Engineering, Koenigin-Luise-Str. 22, D-14195 Berlin (Germany); Heinz, V [German Institute of Food Technology, p. o. box 1165, D-49601, Quackenbrueck (Germany)], E-mail: alexander.mathys@tu-berlin.de

    2008-07-15

    The mechanism of inactivation of bacterial spores by heat and pressure is still a matter of discussion. Obviously, the change of the dissociation equilibrium under pressure and temperature plays a dominant role in inactivation of microorganisms. Heat and pressure inactivation of Geobacillus. stearothermophilus spores at different initial pH-values in ACES and phosphate buffer confirmed this view. Thermal inactivation in ACES buffer at 122 deg. C resulted in higher logarithmic reductions. Contrary, after pressure treatment at 900 MPa with 80 deg. C phosphate buffer showed higher inactivation. These results indicated the different dissociation equilibrium shifts in buffer systems by heat and pressure. Due to preparation, storage and handling of highly concentrated spore suspensions the clumping and the formation of aggregates can hardly be avoided. Consequently, the impact of the agglomeration size distribution on the quantitative assessment of G. stearothermophilus spore inactivation was determined by using a three-fold dynamic optical backreflexion measurement. Two limiting cases have been discriminated in mathematical modelling: three dimensional, spherical packing for maximum spore count and two dimensional, circular packing for minimum spore count of a particular agglomerate. Thermal inactivation studies have been carried out in thin glass capillaries, where by using numerical simulations the non isothermal conditions were modelled and taken into account. It is shown that the shoulder formation often found in thermal spore inactivation can sufficiently be described by first-order inactivation kinetics when the agglomeration size is considered. In case of high pressure inactivation agglomerations could be strongly changed by high forces at compression and especially decompression phase. The physiological response of Bacillus licheniformis spores to high pressure was investigated using multiparameter flow cytometry. Spores were treated by high pressure at 150 MPa

  3. Hourly predictive artificial neural network and multivariate regression tree models of Alternaria and Cladosporium spore concentrations in Szczecin (Poland)

    Science.gov (United States)

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2009-11-01

    A study was made of the link between time of day, weather variables and the hourly content of certain fungal spores in the atmosphere of the city of Szczecin, Poland, in 2004-2007. Sampling was carried out with a Lanzoni 7-day-recording spore trap. The spores analysed belonged to the taxa Alternaria and Cladosporium. These spores were selected both for their allergenic capacity and for their high level presence in the atmosphere, particularly during summer. Spearman correlation coefficients between spore concentrations, meteorological parameters and time of day showed different indices depending on the taxon being analysed. Relative humidity (RH), air temperature, air pressure and clouds most strongly and significantly influenced the concentration of Alternaria spores. Cladosporium spores correlated less strongly and significantly than Alternaria. Multivariate regression tree analysis revealed that, at air pressures lower than 1,011 hPa the concentration of Alternaria spores was low. Under higher air pressure spore concentrations were higher, particularly when RH was lower than 36.5%. In the case of Cladosporium, under higher air pressure (>1,008 hPa), the spores analysed were more abundant, particularly after 0330 hours. In artificial neural networks, RH, air pressure and air temperature were the most important variables in the model for Alternaria spore concentration. For Cladosporium, clouds, time of day, air pressure, wind speed and dew point temperature were highly significant factors influencing spore concentration. The maximum abundance of Cladosporium spores in air fell between 1200 and 1700 hours.

  4. Lattice Boltzmann simulation for temperature-sensitive magnetic fluids in a porous square cavity

    International Nuclear Information System (INIS)

    Jin Licong; Zhang Xinrong; Niu Xiaodong

    2012-01-01

    A lattice Boltzmann method is developed to simulate temperature-sensitive magnetic fluids in a porous cavity. In the simulation, the magnetic force, efficient gravity, viscous loss term and geometric loss term in porous medium are imported to the momentum equation. To test the reliability of the method, a validation with water in porous cavity is carried out. Good agreements with the previous results verify that the present lattice Boltzmann method is promising for simulation of magnetic fluids in porous medium. In this study, we investigate the change of magnetization with external magnetic field, and we present numerical results for the streamlines, isotherms, and magnetization at vertical or horizontal mid-profiles for different values of Ram. In addition, Nusselt numbers changing with magnetic Rayleigh numbers are also investigated. - Highlights: → Developed a lattice Boltzmann method for magnetic nano-fluids in porous cavity. → Clarified flow and heat transfer for different values of (magnetic) Rayleigh numbers. → Heat transfer enhancement for magnetic fluid in porous cavity.

  5. Diurnal variations of airborne fungal spores concentration in the town and rural area

    Directory of Open Access Journals (Sweden)

    Idalia Kasprzyk

    2012-12-01

    Full Text Available Airborne fungal spores were monitored in 2001-2002 in Rzeszów (town and its neighborhood. The aim of investigations was to ascertain if there were differences in diurnal variations of airborne fungal spores concentration between town and rural area. The sampling was carried out using volumetric method. Traps were located at the same heights - app. 12 m. Airborne spores were sampled continuously. Microscopical slides were prepared for each day. Analysis was carried out on one longitudinal band of 48 mm long divided into 24 segments corresponding following hours of day. The results were expressed as mean number of fungal spores per cubic meter per 24 hours. For this survey, five geni of allergenic fungi were selected: Alternaria, Botrytis, Cladosporium, Epicoccum, Ganoderma. The concentrations of their airborne spores were high or very high. It was calculated theoretical day, where the hourly count was the percentage mean of number of spores at that time every chosen day without rainfall from 2001 and 2001 years. The diurnal periodicity of Alternaria, Cladosporium, Epicoccum and Ganoderma showed one peak, while Botrytis two. Anamorphic spores peaked in the afternoon, while their minima occurred in the morning. The highest concentrations of Ganoderma basidiospores were at down or at night, but minima during the day. There were no clear differences in the peak values between two studied sites. The results indicate that maximum concentrations of all spores generally occurred a few hour earlier in the rural area than in the town. Probably, in the rural area airborne spores came from many local sources and their diurnal periodicity reflected rhythm of spore liberation. Towns are characterized by specific microclimate with higher temperature and wind blowing to the centre. In Rzeszów fungal spores could be transported outside and carried out by wind from distant sources. This study showed, among others, that habitat conditions are an important factors

  6. Spore Coat Architecture of Clostridium novyi-NT spores

    Energy Technology Data Exchange (ETDEWEB)

    Plomp, M; McCafferey, J; Cheong, I; Huang, X; Bettegowda, C; Kinzler, K; Zhou, S; Vogelstein, B; Malkin, A

    2007-05-07

    Spores of the anaerobic bacterium Clostridium novyi-NT are able to germinate in and destroy hypoxic regions of tumors in experimental animals. Future progress in this area will benefit from a better understanding of the germination and outgrowth processes that are essential for the tumorilytic properties of these spores. Towards this end, we have used both transmission electron microscopy and atomic force microscopy to determine the structure of dormant as well as germinating spores. We found that the spores are surrounded by an amorphous layer intertwined with honeycomb parasporal layers. Moreover, the spore coat layers had apparently self-assembled and this assembly was likely to be governed by crystal growth principles. During germination and outgrowth, the honeycomb layers as well as the underlying spore coat and undercoat layers sequentially dissolved until the vegetative cell was released. In addition to their implications for understanding the biology of C. novyi-NT, these studies document the presence of proteinaceous growth spirals in a biological organism.

  7. A mobile genetic element profoundly increases heat resistance of bacterial spores.

    Science.gov (United States)

    Berendsen, Erwin M; Boekhorst, Jos; Kuipers, Oscar P; Wells-Bennik, Marjon H J

    2016-11-01

    Bacterial endospores are among the most resilient forms of life on earth and are intrinsically resistant to extreme environments and antimicrobial treatments. Their resilience is explained by unique cellular structures formed by a complex developmental process often initiated in response to nutrient deprivation. Although the macromolecular structures of spores from different bacterial species are similar, their resistance to environmental insults differs widely. It is not known which of the factors attributed to spore resistance confer very high-level heat resistance. Here, we provide conclusive evidence that in Bacillus subtilis, this is due to the presence of a mobile genetic element (Tn1546-like) carrying five predicted operons, one of which contains genes that encode homologs of SpoVAC, SpoVAD and SpoVAEb and four other genes encoding proteins with unknown functions. This operon, named spoVA 2mob , confers high-level heat resistance to spores. Deletion of spoVA 2mob in a B. subtilis strain carrying Tn1546 renders heat-sensitive spores while transfer of spoVA 2mob into B. subtilis 168 yields highly heat-resistant spores. On the basis of the genetic conservation of different spoVA operons among spore-forming species of Bacillaceae, we propose an evolutionary scenario for the emergence of extremely heat-resistant spores in B. subtilis, B. licheniformis and B. amyloliquefaciens. This discovery opens up avenues for improved detection and control of spore-forming bacteria able to produce highly heat-resistant spores.

  8. Higher temperature variability reduces temperature sensitivity of vegetation growth in Northern Hemisphere

    Science.gov (United States)

    Wu, Xiuchen; Liu, Hongyan; Li, Xiaoyan; Piao, Shilong; Ciais, Philippe; Guo, Weichao; Yin, Yi; Poulter, Ben; Peng, Changhui; Viovy, Nicolas; Vuichard, Nicolas; Wang, Pei; Huang, Yongmei

    2017-06-01

    Interannual air temperature variability has changed over some regions in Northern Hemisphere (NH), accompanying with climate warming. However, whether and to what extent it regulates the interannual sensitivity of vegetation growth to temperature variability (i.e., interannual temperature sensitivity)—one central issue in understanding and predicting the responses of vegetation growth to changing climate—still remains poorly quantified and understood. Here we quantify the relationships between the interannual temperature sensitivity of mean growing-season (April-October) normalized difference vegetation index (NDVI) and ecosystem model simulations of gross primary productivity (GPP), and variability in mean growing-season temperature for forest, shrub, and grass over NH. We find that higher interannual variability in mean growing-season temperature leads to consistent decrease in interannual temperature sensitivity of mean growing-season NDVI among all vegetation types but not in model simulations of GPP. Drier condition associates with 130 ± 150% further decrease in interannual temperature sensitivity of mean growing-season NDVI by temperature variability in forest and shrub. These results illustrate that varying temperature variability can significantly regulate the interannual temperature sensitivity of vegetation growth over NH, interacted with drought variability and nonlinear responses of photosynthesis to temperature. Our findings call for an improved characterization of the nonlinear effects of temperature variability on vegetation growth within global ecosystem models.

  9. Effects of meteorological factors on the levels of Alternaria spores on a potato crop

    Science.gov (United States)

    Escuredo, Olga; Seijo, Maria Carmen; Fernández-González, Maria; Iglesias, Isabel

    2011-03-01

    Alternaria solani Soraeur produces early blight in Solanum tuberosum L., leading to significant agricultural losses. The current study was carried out on the extensive potato crop situated in north-western of Spain during 2007, 2008 and 2009. In this area potato crops are the most important source of income. In this work we used a Hirst-type volumetric spore-trap for the aerobiological monitoring of Alternaria spores. The highest spore concentrations were recorded during the 2009 cycle (10,555 spores), and the lowest concentrations were recorded during the 2008 cycle (5,471 spores). Over the 3 years of study, the highest concentrations were registered during the last stage of the crop. The aim of the study was to observe the influence of meteorological factors on the concentration of Alternaria spores, which can lead to serious infection and early blight. Prediction of the stages during which a crop is particularly vulnerable to infection allows for adjustment of the application of fungicide and is of environmental and agricultural importance. For this reason, we tested three models (P-Days, DD and IWP) to predict the first treatment and decrease the negative effect that these spores have on potato crops. The parameter that showed the most significant correlation with spore concentrations was minimum temperature. We used ARIMA (autoregressive integrated model of running mean) time-series models to determine the forecast. We considered weather data as predictor variables and the concentration of spores on the previous day as the fixed variable.

  10. Rational design of temperature-sensitive alleles using computational structure prediction.

    Directory of Open Access Journals (Sweden)

    Christopher S Poultney

    Full Text Available Temperature-sensitive (ts mutations are mutations that exhibit a mutant phenotype at high or low temperatures and a wild-type phenotype at normal temperature. Temperature-sensitive mutants are valuable tools for geneticists, particularly in the study of essential genes. However, finding ts mutations typically relies on generating and screening many thousands of mutations, which is an expensive and labor-intensive process. Here we describe an in silico method that uses Rosetta and machine learning techniques to predict a highly accurate "top 5" list of ts mutations given the structure of a protein of interest. Rosetta is a protein structure prediction and design code, used here to model and score how proteins accommodate point mutations with side-chain and backbone movements. We show that integrating Rosetta relax-derived features with sequence-based features results in accurate temperature-sensitive mutation predictions.

  11. Effect of irradiation of bacteria on the formation of spores

    International Nuclear Information System (INIS)

    Szulc, M.; Tropilo, J.; Olszewski, G.

    1980-01-01

    Studies were carried out on bacteria: Bac. subtilis, Bac. cereus, Cl. perfringens, Cl. botulinum which were irradiated in two media (PBS and broth containing 1% of protein) with 100, 1000, 5000 and 10 000 X-radiation doses. The results obtained show that: all bacteria species studied (vegetative forms) are characterized by a high sensitivity to X-radiation, though distinctly lower than the species of Enterobacteriaceae family; the bacteria species studied are characterized by various sporing rate. The highest sporing rate was shown by Bac. cereus, the following: Bac. subtilis, Cl. perfringens and Cl. botulinum; increased X-radiation doses weaken sporing of Bac. subtilis and Bac. cereus. This effect could not be observed in Cl. perfringens and Cl. botulinum. (author)

  12. Temperature-Sensitive Mutants of Mouse Hepatitis Virus Strain A59: Isolation, Characterization and Neuropathogenic Properties.

    NARCIS (Netherlands)

    M.J.M. Koolen (Marck); A.D.M.E. Osterhaus (Albert); G. van Steenis (Bert); M.C. Horzinek; B.A.M. van der Zeijst (Ben)

    1983-01-01

    textabstractTwenty 5-fluorouracil-induced temperature-sensitive (ts) mutants of mouse hepatitis virus strain A59 were isolated from 1284 virus clones. Mutants were preselected on the basis of their inability to induce syncytia in infected cells at the restrictive temperature (40 degrees) vs the

  13. Alginate microgels loaded with temperature sensitive liposomes for magnetic resonance imageable drug release and microgel visualization

    NARCIS (Netherlands)

    van Elk, M.; Lorenzato, C.; Ozbakir, B.; Oerlemans, C.; Storm, Gerrit; Nijsen, F.; Deckers, R.; Vermonden, T.; Hennink, W.E.

    2015-01-01

    The objective of this study was to prepare and characterize alginate microgels loaded with temperature sensitive liposomes, which release their payload after mild hyperthermia. It is further aimed that by using these microgels both the drug release and the microgel deposition can be visualized by

  14. Small-Angle Neutron Scattering Study of Structural Changes in Temperature-Sensitive Microgel Colloids

    NARCIS (Netherlands)

    Stieger, M.A.; Richtering, W.; Pedersen, J.S.; Lindner, P.

    2004-01-01

    The structure of temperature-sensitive poly(N-isopropylacrylamide) microgels in dilute suspension was investigated by means of small-angle neutron scattering. A direct modeling expression for the scattering intensity distribution was derived which describes very well the experimental data at all

  15. Temperature sensitivity of differential absorption lidar measurements of water vapor in the 720-nm region

    Science.gov (United States)

    Browell, Edward V.; Ismail, Syed; Grossmann, Benoist E.

    1991-01-01

    Recently measured properties of water vapor (H2O) absorption lines have been used in calculations to evalute the temperature sensitivity of differential absorption lidar (Dial) H2O measurements. This paper estimates the temperature sensitivity of H2O lines in the 717-733-nm region for both H2O mixing ratio and number density measurements, and discusses the influence of the H2O line ground state energies E-double-prime, the H2O absorption linewidths, the linewidth temperature dependence parameter, and the atmospheric temperature and pressure variations with altitude and location on the temperature sensitivity calculations. Line parameters and temperature sensitivity calculations for 67 H2O lines in the 720-nm band are given which can be directly used in field experiments. Water vapor lines with E-double-prime values in the 100-300/cm range were found to be optimum for Dial measurements of H2O number densities, while E-double-prime values in the 250-500/cm range were found to be optimum for H2O mixing ratio measurements.

  16. The effects of substrate supply on the temperature sensitivity of soil carbon decomposition

    Science.gov (United States)

    Cinzia Fissore; Christian P. Giardina; Randall K. Kolka

    2013-01-01

    Controls on the decomposition rate of soil organic carbon (SOC), especially the more stable fraction of SOC, remain poorly understood, with implications for confidence in efforts to model terrestrial C balance under future climate. We investigated the role of substrate supply in the temperature sensitivity of SOC decomposition in laboratory incubations of coarse-...

  17. Gene expression profiling of a temperature-sensitive strain of Neospora caninum

    Science.gov (United States)

    To understand the genetic basis of virulence, gene expression profiles of a temperature-sensitive clone (NCts-8, relatively avirulent) and its wild type (NC-1) of Neospora caninum were characterized and compared using a high-density microarray with approximately 63,000 distinct oligonucleotides. Thi...

  18. Validation of temperature-sensitive radio transmitters for measurement of body temperature in small animals

    NARCIS (Netherlands)

    Williams, Joseph B.; Tieleman, B. I.; Shobrak, Mohammed

    2009-01-01

    As part of a study on the core body temperature (T(b)) of desert birds, we purposed to use temperature-sensitive implantable radio transmitters. Because of the difficulty in recapturing these birds, we needed to know if these electronic devices held their calibration over the duration of normal

  19. Temperature sensitivity of soil respiration is dependent on readily decomposable C substrate concentration

    Science.gov (United States)

    Larionova, A. A.; Yevdokimov, I. V.; Bykhovets, S. S.

    2007-06-01

    Temperature acclimation of soil organic matter (SOM) decomposition is one of the major uncertainties in predicting soil CO2 efflux by the increase in global mean temperature. A reasonable explanation for an apparent acclimation proposed by Davidson and colleagues (2006) based on Michaelis-Menten kinetics suggests that temperature sensitivity decreases when both maximal activity of respiratory enzymes (Vmax) and half- saturation constant (Ks) cancel each other upon temperature increase. We tested the hypothesis of the canceling effect by the mathematical simulation of the data obtained in the incubation experiments with forest and arable soils. Our data confirm the hypothesis and suggest that concentration of readily decomposable C substrate as glucose equivalent is an important factor controlling temperature sensitivity. The highest temperature sensitivity was observed when C substrate concentration was much lower than Ks. Increase of substrate content to the half-saturation constant resulted in temperature acclimation associated with the canceling effect. Addition of the substrate to the level providing respiration at a maximal rate Vmax leads to the acclimation of the whole microbial community as such. However, growing microbial biomass was more sensitive to the temperature alterations. This study improves our understanding of the instability of temperature sensitivity of soil respiration under field conditions, explaining this phenomenon by changes in concentration of readily decomposable C substrate. It is worth noting that this pattern works regardless of the origin of C substrate: production by SOM decomposition, release into the soil by rhizodeposition, litter fall or drying-rewetting events.

  20. Updates on Clostridium difficile spore biology.

    Science.gov (United States)

    Gil, Fernando; Lagos-Moraga, Sebastián; Calderón-Romero, Paulina; Pizarro-Guajardo, Marjorie; Paredes-Sabja, Daniel

    2017-06-01

    Clostridium difficile is a Gram-positive, anaerobic spore former, and an important nosocomial pathogenic bacterium. C. difficile spores are the morphotype of transmission and recurrence of the disease. The formation of C. difficile spores and their subsequent germination are essential processes during the infection. Recent in vitro and in vivo work has shed light on how spores are formed and the timing of in vivo sporulation in a mouse model. Advances have also been made in our understanding of the machineries involved in spore germination, and how antibiotic-induced dysbiosis affects the metabolism of bile salts and thus impacts C. difficile germination in vivo. Studies have also attempted to identify how C. difficile spores interact with the host's intestinal mucosa. Spore resistance has also been revisited by several groups highlighting the extreme resistance of this morphotype to traditional food processing regimes and disinfectants used in clinical settings. Therefore, the aim of this review is to summarize recent advances on spore formation/germination in vitro and in vivo, spore-host interactions, and spore resistance that contribute to our knowledge of the role of C. difficile spores in the infectious process. Copyright © 2017. Published by Elsevier Ltd.

  1. Photometric immersion refractometry of bacterial spores.

    Science.gov (United States)

    Gerhardt, P; Beaman, T C; Corner, T R; Greenamyre, J T; Tisa, L S

    1982-01-01

    Photometric immersion refractometry was used to determine the average apparent refractive index (n) of five types of dormant Bacillus spores representing a 600-fold range in moist-heat resistance determined as a D100 value. The n of a spore type increased as the molecular size of various immersion solutes decreased. For comparison of the spore types, the n of the entire spore and of the isolated integument was determined by use of bovine serum albumin, which is excluded from permeating into them. The n of the sporoplast (the structures bounded by the outer pericortex membrane) was determined by use of glucose, which was shown to permeate into the spore only as deeply as the pericortex membrane. Among the various spore types, an exponential increase in the heat resistance correlated with the n of the entire spore and of the sporoplast, but not of the isolated perisporoplast integument. Correlation of the n with the solids content of the entire spore provided a method of experimentally obtaining the refractive index increment (dn/dc), which was constant for the various spore types and enables the calculation of solids and water content from an n. Altogether, the results showed that the total water content is distributed unequally within the dormant spore, with less water in the sporoplast than in the perisporoplast integument, and that the sporoplast becomes more refractile and therefore more dehydrated as the heat resistance becomes greater among the various spore types. PMID:6802796

  2. Nonwoven supported temperature-sensitive poly(N-isopropylacrylamide)/polyurethane copolymer hydrogel with antibacterial activity.

    Science.gov (United States)

    Liu, Baohua; Hu, Jinlian; Meng, Qinghao

    2009-04-01

    This article is focused on the study of the antibacterial activity of temperature sensitive poly(N-isopropylacrylamide/polyurethane (PNIPAAm/PU) hydrogel grafted nonwoven fabrics with chitosan modification. A series of temperature sensitive hydrogel grafted nonwoven fabrics with different N-isopropylacrylamide/polyurethane (NIPAAm/PU) feeding ratios have been synthesized by using ammonium persulfate (APS) as initiator and N,N,N',N'-tetramethyl-ethane-1,2-diamine (TEMED) as accelerator. FTIR and XPS were used to examine the surface modification of chitosan. The phase transition temperature of hydrogel grafted nonwoven fabrics was about 32 degrees C by DSC. S. aureus and E. coli were used to evaluate the antibacterial efficiency of the fabric composite. After chitosan modification, the hydrogel grafted nonwoven cellulose fabrics demonstrates an antibacterial activity to S. aureus. and E. coli and the antibacterial efficiency is about 80%.

  3. Evaluation of surface sampling method performance for Bacillus Spores on clean and dirty outdoor surfaces.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Mollye C.; Einfeld, Wayne; Boucher, Raymond M.; Brown, Gary Stephen; Tezak, Matthew Stephen

    2011-06-01

    Recovery of Bacillus atrophaeous spores from grime-treated and clean surfaces was measured in a controlled chamber study to assess sampling method performance. Outdoor surfaces investigated by wipe and vacuum sampling methods included stainless steel, glass, marble and concrete. Bacillus atrophaeous spores were used as a surrogate for Bacillus anthracis spores in this study designed to assess whether grime-coated surfaces significantly affected surface sampling method performance when compared to clean surfaces. A series of chamber tests were carried out in which known amounts of spores were allowed to gravitationally settle onto both clean and dirty surfaces. Reference coupons were co-located with test coupons in all chamber experiments to provide a quantitative measure of initial surface concentrations of spores on all surfaces, thereby allowing sampling recovery calculations. Results from these tests, carried out under both low and high humidity conditions, show that spore recovery from grime-coated surfaces is the same as or better than spore recovery from clean surfaces. Statistically significant differences between method performance for grime-coated and clean surfaces were observed in only about half of the chamber tests conducted.

  4. Imaging heat transfer processes in a fluid with temperature sensitive paint

    Science.gov (United States)

    Huang, Jun; Liu, Tianshu; Luo, Weili

    2014-03-01

    The temperature profile inside a fluid was imaged by temperature sensitive paint in a quasi one-dimensional cell, where temperature gradients were established by heating on one side of the sample and cooling on the other. Similar experiment was performed on colloids consisting nanoparticles suspended in solvent. The change of the profile for different heat-transfer processes as functions of time will be discussed.

  5. Allele-specific suppression of the temperature sensitivity of fitA/fitB ...

    Indian Academy of Sciences (India)

    The temperature sensitive transcription defective mutant of Escherichia coli originally called fitA76 has been shown to harbour two missense mutations namely pheS5 and fit95. In order to obtain a suppressor of fitA76, possibly mapping in rpoD locus, a Ts+ derivative (JV4) was isolated from a fitA76 mutant. It was found that ...

  6. Soil organic matter decomposition and temperature sensitivity after forest fire in permafrost regions in Canada

    Science.gov (United States)

    Aaltonen, Heidi; Palviainen, Marjo; Köster, Kajar; Berninger, Frank; Pumpanen, Jukka

    2017-04-01

    On the Northern Hemisphere, 24% of soils are underlain by permafrost. These soils contain 50% of the global soil carbon pool. The Northern Hemisphere is also the region which is predicted to be most affected by climate warming and this causes uncertainties over the future of the permafrost. It has been estimated that 25% of permafrost might thaw by 2100, exposing previously frozen carbon pools to decomposition. In addition, global warming is expected to cause increase in the frequency of wild fires, which further increase permafrost melting by removing the insulating organic surface layer. The amount of released soil carbon from permafrost soils after forest fire is affected by degradability and temperature sensitivity of the soil organic matter, as well as soil depth and the stage of succession. Yet the common effect of these factors remains unclear. We studied how soil respiration and its temperature sensitivity (Q10) vary in different depths and within time by taking soil samples from different fire chronosequence areas (burned 3, 25, 46 and 100 years ago) from permafrost region in Northern Canada (Yukon and Northwest Territories, along Dempster Highway). The samples from three different depths (5, 10 and 30 cm) were incubated in four different temperatures (1, 7, 13 and 19°C) over 24h. Our results showed that the CO2 fluxes followed the stages of succession, with recently burned sites having lowest rates. The organic matter at 5 cm depth proved to be more labile and temperature sensitive than in deeper depths. The Q10 values, however, did not differ between sites, excluding 30 cm at the most recently burned site that had a significantly higher Q10 value than the other sites. The results implicate that heterotrophic soil respiration decreases on permafrost regions during the first stages after forest fire. At the same time the temperature sensitivity in deeper soil layers may increase.

  7. Temperature sensitivity of soil respiration rates enhanced by microbial community response.

    Science.gov (United States)

    Karhu, Kristiina; Auffret, Marc D; Dungait, Jennifer A J; Hopkins, David W; Prosser, James I; Singh, Brajesh K; Subke, Jens-Arne; Wookey, Philip A; Agren, Göran I; Sebastià, Maria-Teresa; Gouriveau, Fabrice; Bergkvist, Göran; Meir, Patrick; Nottingham, Andrew T; Salinas, Norma; Hartley, Iain P

    2014-09-04

    Soils store about four times as much carbon as plant biomass, and soil microbial respiration releases about 60 petagrams of carbon per year to the atmosphere as carbon dioxide. Short-term experiments have shown that soil microbial respiration increases exponentially with temperature. This information has been incorporated into soil carbon and Earth-system models, which suggest that warming-induced increases in carbon dioxide release from soils represent an important positive feedback loop that could influence twenty-first-century climate change. The magnitude of this feedback remains uncertain, however, not least because the response of soil microbial communities to changing temperatures has the potential to either decrease or increase warming-induced carbon losses substantially. Here we collect soils from different ecosystems along a climate gradient from the Arctic to the Amazon and investigate how microbial community-level responses control the temperature sensitivity of soil respiration. We find that the microbial community-level response more often enhances than reduces the mid- to long-term (90 days) temperature sensitivity of respiration. Furthermore, the strongest enhancing responses were observed in soils with high carbon-to-nitrogen ratios and in soils from cold climatic regions. After 90 days, microbial community responses increased the temperature sensitivity of respiration in high-latitude soils by a factor of 1.4 compared to the instantaneous temperature response. This suggests that the substantial carbon stores in Arctic and boreal soils could be more vulnerable to climate warming than currently predicted.

  8. Ultraviolet-Resistant Bacterial Spores

    Science.gov (United States)

    Venkateswaran, Kasthuri; Newcombe, David; LaDuc, Myron T.; Osman, Shariff R.

    2007-01-01

    A document summarizes a study in which it was found that spores of the SAFR-032 strain of Bacillus pumilus can survive doses of ultraviolet (UV) radiation, radiation, and hydrogen peroxide in proportions much greater than those of other bacteria. The study was part of a continuing effort to understand the survivability of bacteria under harsh conditions and develop means of sterilizing spacecraft to prevent biocontamination of Mars that could interfere with the search for life there.

  9. Spore liberation in mosses revisited.

    Science.gov (United States)

    Gallenmüller, Friederike; Langer, Max; Poppinga, Simon; Kassemeyer, Hanns-Heinz; Speck, Thomas

    2018-02-01

    The ability to perform hygroscopic movements has evolved in many plant lineages and relates to a multitude of different functions such as seed burial, flower protection or regulation of diaspore release. In most mosses, spore release is controlled by hygroscopic movements of the peristome teeth and also of the spore capsule. Our study presents, for the first time, temporally and spatially well-resolved kinematic analyses of these complex shape changes in response to humidity conditions and provides insights into the sophisticated functional morphology and anatomy of the peristome teeth. In Brachythecium populeum the outer teeth of the peristome perform particularly complex hygroscopic movements during hydration and desiccation. Hydration induces fast inward dipping followed by partial re-straightening of the teeth. In their final shape, wet teeth close the capsule. During desiccation, the teeth perform an outward flicking followed by a re-straightening which opens the capsule. We present a kinematic analysis of these shape changes and of the underlying functional anatomy of the teeth. These teeth are shown to be composed of two layers which show longitudinal gradients in their material composition, structure and geometry. We hypothesize that these gradients result in (i) differences in swelling/shrinking capacity and velocity between the two layers composing the teeth, and in (ii) a gradient of velocity of swelling and shrinking from the tip to the base of the teeth. We propose these processes explain the observed movements regulating capsule opening or closing. This hypothesis is corroborated by experiments with isolated layers of peristome teeth. During hydration and desiccation, changes to the shape and mass of the whole spore capsule accompany the opening and closing. Results are discussed in relation to their significance for humidity-based regulation of spore release.

  10. In vitro mutagenesis of commercial fern, Asplenium nidus from spores

    International Nuclear Information System (INIS)

    Norazlina Noordin

    2004-01-01

    Asplenium is a largest, most diverse fern genera. One of the common species is Asplenium nidus, well known as Bird's-nest fern, a medium to large fern with erect, stout, unbranched rhizomes. In creating variability of ferns for the benefit of the ornamental plant industry, in vitro mutagenesis is used. In this study, spores of Asplenium nidus were collected from frond bearing mature sporangia. Spores were cultured in modified 1/2 MS basal medium supplemented with various combinations of 6-Benzylaminopurine (BAP) and Naphtalene Acetic Acid (NAA). Spore cultures were incubated in incubation room at 24 degree C with 16 hours photoperiod (3500 lux). It was found that, the most effective combinations were 1 mg/1 BAP + 0. 1 mg/1 NAA and 2mg/1 BAP + 0. 1 mg/1 NAA. Prothallus was formed after 10 days of cultures and gametophytes were formed 1 month later. These gametophytes were irradiated with Gamma ray at doses of 0, 20, 90, 120, 150 and 180 Gy. From the preliminary result obtained from this study, for generating variations and desired phenotypic expression for Asplenium nidus, recommended doses for in vitro mutagenesis using spores are between 90 Gy to 150 Gy. Gametophytes were subcultured at monthly interval to ensure further development and propagation. Frequent monitoring for any changes in the morphology of the irradiated Asplenium nidus plants were carried out. (Author)

  11. Effects of steam autoclave treatment on Geobacillus stearothermophilus spores.

    Science.gov (United States)

    Huesca-Espitia, L C; Suvira, M; Rosenbeck, K; Korza, G; Setlow, B; Li, W; Wang, S; Li, Y-Q; Setlow, P

    2016-11-01

    To determine the mechanism of autoclave killing of Geobacillus stearothermophilus spores used in biological indicators (BIs) for steam autoclave sterilization, and rates of loss of spore viability and a spore enzyme used in BIs. Spore viability, dipicolinic acid (DPA) release, nucleic acid staining, α-glucosidase activity, protein structure and mutagenesis were measured during autoclaving of G. stearothermophilus spores. Loss of DPA and increases in spore core nucleic acid staining were slower than loss of spore viability. Spore core α-glucosidase was also lost more slowly than spore viability, although soluble α-glucosidase in spore preparations was lost more rapidly. However, spores exposed to an effective autoclave sterilization lost all viability and α-glucosidase activity. Apparently killed autoclaved spores were not recovered by artificial germination in supportive media, much spore protein was denatured during autoclaving, and partially killed autoclave-treated spore preparations did not acquire mutations. These results indicate that autoclave-killed spores cannot be revived, spore killing by autoclaving is likely by protein damage, and spore core α-glucosidase activity is lost more slowly than spore viability. This work provides insight into the mechanism of autoclave killing of spores of an organism used in BIs, and that a spore enzyme in a BI is more stable to autoclaving than spore viability. © 2016 The Society for Applied Microbiology.

  12. Arbuscular mycorrhizal fungi spore propagation using single spore as starter inoculum and a plant host.

    Science.gov (United States)

    Gopal, Selvakumar; Shagol, Charlotte C; Kang, Yeongyeong; Chung, Bong Nam; Han, Seung Gab; Tong-Min, Sa

    2018-02-02

    The propagation of pure cultures of AMF is an essential requirement for their large scale agricultural application and commercialization as biofertilizers. The present study aimed to propagate AMF using the single spore inoculation technique and compare their propagation ability with the known reference spores. Arbuscular mycorrhizal fungal spores were collected from the salt-affected Saemangeum reclaimed soil in South Korea. The technique involved inoculation of Sorghum-Sudan grass (Sorghum bicolor L.) seedlings with single, healthy spores on filter paper followed by the transfer of successfully colonized seedlings to 1 kg capacity pots containing sterilized soil. After the first plant cycle, the contents were transferred to 2.5 kg capacity pots containing sterilized soil. Among the 150 inoculants, only 27 seedlings were colonized by AMF spores. After 240 days, five inoculants among the 27 seedlings resulted in the production of over 500 spores. The 18S rDNA sequencing of spores revealed that the spores produced through single spore inoculation method belonged to Gigaspora margarita, Claroideoglomus lamellosum, and Funneliformis mosseae. Furthermore, indigenous spore Funneliformis mosseae M-1 reported a higher spore count than the reference spores. The AMF spores produced using single spore inoculation technique may serve as potential bio-inoculants with an advantage of being more readily adopted by farmers due to the lack of requirement of a skilled technique in spore propagation. The results of the current study describes the feasible and cost effective method to mass produce AMF spores for large scale application. The AMF spores obtained from this method can effectively colonize plant roots and may be easily introduced to the new environment. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  13. The Temperature Optima and Temperature Sensitivity of Soil Respiration Explained By Macromolecular Rate Theory (MMRT).

    Science.gov (United States)

    Schipper, L. A.; O'Neill, T.; Arcus, V. L.

    2014-12-01

    One of the most fundamental factors controlling all biological and chemical processes is changing temperature. Temperature dependence was originally described by the Arrhenius function in the 19th century. This function provides an excellent description of chemical reaction rates. However, the Arrhenius function does not predict the temperature optimum of biological rates that is clearly evident in laboratory and field measurements. Previously, the temperature optimum of biological processes has been ascribed to denaturation of enzymes but the observed temperature optima in soil are often rather modest, occurring at about 40-50°C and generally less than recognised temperatures for protein unfolding. We have modified the Arrhenius function incorporating a temperature-dependent activation energy derived directly from first principles from thermodynamics of macromolecules. MacroMolecular Rate Theory (MMRT) accounts for large changes in the flexibility of enzymes during catalysis that result in changes in heat capacity (ΔC‡p) of the enzyme during the reaction. MMRT predicts an initially Arrhenius-like response followed by a temperature optimum without the need for enzyme denaturation (Hobbs et al., 2013. ACS Chemical Biology. 8: 2388-2393). Denaturation, of course, occurs at much higher temperatures. We have shown that MMRT fits biogeochemical data collected from laboratory and field studies with important implications for changes in absolute temperature sensitivity as temperature rises (Schipper et al., 2014. Global Change Biology). As the temperature optimum is approached the absolute temperature sensitivity of biological processes decreases to zero. Consequently, the absolute temperature-sensitivity of soil biological processes depends on both the change in ecosystem temperature and the temperature optimum of the biological process. MMRT also very clearly explains why Q10 values decline with increasing temperature more quickly than would be predicted from the

  14. Soil warming increases metabolic quotients of soil microorganisms without changes in temperature sensitivity of soil respiration

    Science.gov (United States)

    Marañón-Jiménez, Sara; Soong, Jenniffer L.; Leblans, Niki I. W.; Sigurdsson, Bjarni D.; Dauwe, Steven; Fransen, Erik; Janssens, Ivan A.

    2017-04-01

    Increasing temperatures can accelerate soil organic matter (SOM) decomposition and release large amounts of CO2 to the atmosphere, potentially inducing climate change feedbacks. Alterations to the temperature sensitivity and metabolic pathways of soil microorganisms in response to soil warming can play a key role in these soil carbon (C) losses. Here, we present results of an incubation experiment using soils from a geothermal gradient in Iceland that have been subjected to different intensities of soil warming (+0, +1, +3, +5, +10 and +20 °C above ambient) over seven years. We hypothesized that 7 years of soil warming would led to a depletion of labile organic substrates, with a subsequent decrease of the "apparent" temperature sensitivity of soil respiration. Associated to this C limitation and more sub-optimal conditions for microbial growth, we also hypothesized increased microbial metabolic quotients (soil respiration per unit of microbial biomass), which is associated with increases in the relative amount of C invested into catabolic pathways along the warming gradient. Soil respiration and basal respiration rates decreased with soil warming intensity, in parallel with a decline in soil C availability. Contrasting to our first hypothesis, we did not detect changes in the temperature sensitivity of soil respiration with soil warming or on the availability of nutrients and of labile C substrates at the time of incubation. However, in agreement to our second hypothesis, microbial metabolic quotients (soil respiration per unit of microbial biomass) increased at warmer temperatures, while the C retained in biomass decreased as substrate became limiting. Long-term (7 years) temperature increases thus triggered a change in the metabolic functioning of the soil microbial communities towards increasing energy costs for maintenance or resource acquisition, thereby lowering the capacity of C retention and stabilization of warmed soils. These results highlight the need

  15. Distinction of broken cellular wall Ganoderma lucidum spores and G. lucidum spores using FTIR microspectroscopy

    Science.gov (United States)

    Chen, Xianliang; Liu, Xingcun; Sheng, Daping; Huang, Dake; Li, Weizu; Wang, Xin

    2012-11-01

    In this paper, FTIR microspectroscopy was used to identify broken cellular wall Ganoderma lucidum spores and G. lucidum spores. For IR spectra, broken cellular wall G. lucidum spores and G. lucidum spores were mainly different in the regions of 3000-2800, 1660-1600, 1400-1200 and 1100-1000 cm-1. For curve fitting, the results showed the differences in the protein secondary structures and the polysaccharide structures/content between broken cellular wall G. lucidum spores and G. lucidum spores. Moreover, the value of A1078/A1741 might be a potentially useful factor to distinguish broken cellular wall G. lucidum spores from G. lucidum spores. Additionally, FTIR microspectroscopy could identify broken cellular wall G. lucidum spores and G. lucidum spores accurately when it was combined with hierarchical cluster analysis. The result suggests FTIR microspectroscopy is very simple and efficient for distinction of broken cellular wall G. lucidum spores and G. lucidum spores. The result also indicates FTIR microspectroscopy may be useful for TCM identification.

  16. Electron Beam Irradiation Dose Dependently Damages the Bacillus Spore Coat and Spore Membrane

    Directory of Open Access Journals (Sweden)

    S. E. Fiester

    2012-01-01

    Full Text Available Effective control of spore-forming bacilli begs suitable physical or chemical methods. While many spore inactivation techniques have been proven effective, electron beam (EB irradiation has been frequently chosen to eradicate Bacillus spores. Despite its widespread use, there are limited data evaluating the effects of EB irradiation on Bacillus spores. To study this, B. atrophaeus spores were purified, suspended in sterile, distilled water, and irradiated with EB (up to 20 kGy. Irradiated spores were found (1 to contain structural damage as observed by electron microscopy, (2 to have spilled cytoplasmic contents as measured by spectroscopy, (3 to have reduced membrane integrity as determined by fluorescence cytometry, and (4 to have fragmented genomic DNA as measured by gel electrophoresis, all in a dose-dependent manner. Additionally, cytometry data reveal decreased spore size, increased surface alterations, and increased uptake of propidium iodide, with increasing EB dose, suggesting spore coat alterations with membrane damage, prior to loss of spore viability. The present study suggests that EB irradiation of spores in water results in substantial structural damage of the spore coat and inner membrane, and that, along with DNA fragmentation, results in dose-dependent spore inactivation.

  17. Species composition and forest structure explain the temperature sensitivity patterns of productivity in temperate forests

    Science.gov (United States)

    Bohn, Friedrich J.; May, Felix; Huth, Andreas

    2018-03-01

    Rising temperatures due to climate change influence the wood production of forests. Observations show that some temperate forests increase their productivity, whereas others reduce their productivity. This study focuses on how species composition and forest structure properties influence the temperature sensitivity of aboveground wood production (AWP). It further investigates which forests will increase their productivity the most with rising temperatures. We described forest structure by leaf area index, forest height and tree height heterogeneity. Species composition was described by a functional diversity index (Rao's Q) and a species distribution index (ΩAWP). ΩAWP quantified how well species are distributed over the different forest layers with regard to AWP. We analysed 370 170 forest stands generated with a forest gap model. These forest stands covered a wide range of possible forest types. For each stand, we estimated annual aboveground wood production and performed a climate sensitivity analysis based on 320 different climate time series (of 1-year length). The scenarios differed in mean annual temperature and annual temperature amplitude. Temperature sensitivity of wood production was quantified as the relative change in productivity resulting from a 1 °C rise in mean annual temperature or annual temperature amplitude. Increasing ΩAWP positively influenced both temperature sensitivity indices of forest, whereas forest height showed a bell-shaped relationship with both indices. Further, we found forests in each successional stage that are positively affected by temperature rise. For such forests, large ΩAWP values were important. In the case of young forests, low functional diversity and small tree height heterogeneity were associated with a positive effect of temperature on wood production. During later successional stages, higher species diversity and larger tree height heterogeneity were an advantage. To achieve such a development, one could plant

  18. Temperature sensing based on multimodal interference in polymer optical fibers: Room-temperature sensitivity enhancement by annealing

    Science.gov (United States)

    Kawa, Tomohito; Numata, Goki; Lee, Heeyoung; Hayashi, Neisei; Mizuno, Yosuke; Nakamura, Kentaro

    2017-07-01

    To date, we have developed a temperature sensor based on multimodal interference in a polymer optical fiber (POF) with an extremely high sensitivity. Here, we experimentally evaluate the influence of annealing (heat treatment) of the POF on the temperature sensitivity at room temperature. We show that the temperature sensitivity is enhanced with increasing annealing temperature, and that, by annealing the POF at 90 °C, we can achieve a temperature sensitivity of +2.17 nm/°C, which is 2.9 times larger than that without annealing (+0.75 nm/°C).

  19. Radiation synthesis of a water-soluble temperature sensitive polymer, activated copolymer and applications in immobilization of proteins

    International Nuclear Information System (INIS)

    Zhai Maolin; Ha Hongfei; Wu Jilan

    1993-01-01

    In this work the radiation polymerization of N-isopropylacrylamide (NIPAAM) in aqueous solutions has been carried out and a water-soluble, temperature sensitive polymer and copolymer were obtained by using γ-rays from Co-60 source at room temperature. We have gained the optimum dose and dose-rate of radiation synthesis of linear polyNIPAAM through determining conversion yield and viscosity. In order to immobilize protein (BSA) and enzyme (HRP) into this water-soluble polymer, we prepared an activated copolymer, poly(N-isopropylacrylamide-co-N-acryloxysuccinimide). The BSA and HRP has been immobilized onto the activated copolymer. The BSA (HRP)/copolymer conjugates still kept the original thermally sensitive properties of the linear polyNIPAAM. The conjugation yield of BSA to the activated copolymer decreased with increasing dose. Immobilized HRP was stable at 0 o C for a long time and has, at least, 4 days stability at room temperature. Immobilized HRP activity was lowered when the temperature was raised. This phenomenon was reversible and the immobilized HRP regained activity. The optimum pH of the immobilized HRP shifted from ca.5 upward to ca. 7. (author)

  20. Higher climatological temperature sensitivity of soil carbon in cold than warm climates

    Science.gov (United States)

    Koven, Charles D.; Hugelius, Gustaf; Lawrence, David M.; Wieder, William R.

    2017-11-01

    The projected loss of soil carbon to the atmosphere resulting from climate change is a potentially large but highly uncertain feedback to warming. The magnitude of this feedback is poorly constrained by observations and theory, and is disparately represented in Earth system models (ESMs). To assess the climatological temperature sensitivity of soil carbon, we calculate apparent soil carbon turnover times that reflect long-term and broad-scale rates of decomposition. Here, we show that the climatological temperature control on carbon turnover in the top metre of global soils is more sensitive in cold climates than in warm climates and argue that it is critical to capture this emergent ecosystem property in global-scale models. We present a simplified model that explains the observed high cold-climate sensitivity using only the physical scaling of soil freeze-thaw state across climate gradients. Current ESMs fail to capture this pattern, except in an ESM that explicitly resolves vertical gradients in soil climate and carbon turnover. An observed weak tropical temperature sensitivity emerges in a different model that explicitly resolves mineralogical control on decomposition. These results support projections of strong carbon-climate feedbacks from northern soils and demonstrate a method for ESMs to capture this emergent behaviour.

  1. Changes in spring arrival dates and temperature sensitivity of migratory birds over two centuries.

    Science.gov (United States)

    Kolářová, Eva; Matiu, Michael; Menzel, Annette; Nekovář, Jiří; Lumpe, Petr; Adamík, Peter

    2017-07-01

    Long-term phenological data have been crucial at documenting the effects of climate change in organisms. However, in most animal taxa, time series length seldom exceeds 35 years. Therefore, we have limited evidence on animal responses to climate prior to the recent warm period. To fill in this gap, we present time series of mean first arrival dates to Central Europe for 13 bird species spanning 183 years (1828-2010). We found a uniform trend of arrival dates advancing in the most recent decades (since the late 1970s). Interestingly, birds were arriving earlier during the cooler early part of the nineteenth century than in the recent warm period. Temperature sensitivity was slightly stronger in the warmest 30-year period (-1.70 ± SD 0.47 day °C -1 ) than in the coldest period (-1.42 ± SD 0.89 day °C -1 ); however, the difference was not statistically significant. In the most recent decades, the temperature sensitivity of both short- and long-distance migrants significantly increased. Our results demonstrate how centennial time series can provide a much more comprehensive perspective on avian responses to climate change.

  2. The temperature sensitivity of soil organic carbon decomposition is not related to labile and recalcitrant carbon.

    Science.gov (United States)

    Tang, Jie; Cheng, Hao; Fang, Changming

    2017-01-01

    The response of resistant soil organic matter to temperature change is crucial for predicting climate change impacts on C cycling in terrestrial ecosystems. However, the response of the decomposition of different soil organic carbon (SOC) fractions to temperature is still under debate. To investigate whether the labile and resistant SOC components have different temperature sensitivities, soil samples were collected from three forest and two grass land sites, along with a gradient of latitude from 18°40'to 43°17'N and elevation from 600 to 3510 m across China, and were incubated under changing temperature (from 12 to 32 oC) for at least 260 days. Soil respiration rates were positively related to the content of soil organic carbon and soil microbial carbon. The temperature sensitivity of soil respiration, presented as Q10 value, varies from 1.93 ± 0.15 to 2.60 ± 0.21. During the incubation, there were no significant differences between the Q10 values of soil samples from different layers of the same site, nor a clear pattern of Q10 values along with the gradient of latitude. The result of this study does not support current opinion that resistant soil carbon decomposition is more sensitive to temperature change than labile soil carbon.

  3. [Effect of grazing on the temperature sensitivity of soil respiration in Hulunber meadow steppe].

    Science.gov (United States)

    Wang, Xu; Yan, Rui-Rui; Deng, Yu; Yan, Yu-Chun; Xin, Xiao-Ping

    2014-05-01

    Grazing is one of the major human activities which lead to disturbance on grassland ecosystem. Quantifying the effect of grazing on the temperature sensitivity of soil respiration ( Q10 ) is essential for accurate assessment of carbon budget in grassland ecosystem. This study was conducted on the grazing gradients experiment platform in Hulunber meadow steppe. Soil respiration was measured by a dynamic closed chamber method (equipped with Li 6400-09, Lincoln, NE, USA) during the growing season in 2011. The results showed that soil respiration had significant seasonal variation and the maximum occurred in July, which was mainly dominated by temperature. The order of average soil respiration during the period from May to September in different treatments was G1 > GO > G2 > G3 > G4 > G5. Comparing with non-grazing treatment, Q10 under heavy grazing conditions (0. 92 Au hm-2) was reduced by about 10% , and was increased a little under light grazing conditions (0. 23 Au hm-2). There was a significant negative correlation between Q15 and grazing intensities (r = 0. 944, P temperature sensitivity of soil respiration to different degrees. The Q10 under different grazing gradients had positive linear regression relationships with aboveground biomass, belowground biomass, soil organic carbon and soil moisture. They could explain 71.0%-85.2% variations of Q10. It was suggested that the variation of Q10 was mainly determined by the change of biotic and environmental factors due to grazing.

  4. Distinct temperature sensitivity of soil carbon decomposition in forest organic layer and mineral soil.

    Science.gov (United States)

    Xu, Wenhua; Li, Wei; Jiang, Ping; Wang, Hui; Bai, Edith

    2014-10-01

    The roles of substrate availability and quality in determining temperature sensitivity (Q10) of soil carbon (C) decomposition are still unclear, which limits our ability to predict how soil C storage and cycling would respond to climate change. Here we determined Q10 in surface organic layer and subsurface mineral soil along an elevation gradient in a temperate forest ecosystem. Q10 was calculated by comparing the times required to respire a given amount of soil C at 15 and 25°C in a 350-day incubation. Results indicated that Q10 of the organic layer was 0.22-0.71 (absolute difference) higher than Q10 of the mineral soil. Q10 in both the organic layer (2.5-3.4) and the mineral soil (2.1-2.8) increased with decreasing substrate quality during the incubation. This enhancement of Q10 over incubation time in both layers suggested that Q10 of more labile C was lower than that of more recalcitrant C, consistent with the Arrhenius kinetics. No clear trend of Q10 was found along the elevation gradient. Because the soil organic C pool of the organic layer in temperate forests is large, its higher temperature sensitivity highlights its importance in C cycling under global warming.

  5. Validated modified Lycopodium spore method development for ...

    African Journals Online (AJOL)

    Validated modified lycopodium spore method has been developed for simple and rapid quantification of herbal powdered drugs. Lycopodium spore method was performed on ingredients of Shatavaryadi churna, an ayurvedic formulation used as immunomodulator, galactagogue, aphrodisiac and rejuvenator. Estimation of ...

  6. Bacillus subtilis Spore Inner Membrane Proteome

    NARCIS (Netherlands)

    Zheng, L.; Abhyankar, W.; Ouwerling, N.; Dekker, H.L.; van Veen, H.; van der Wel, N.N.; Roseboom, W.; de Koning, L.J.; Brul, S.; de Koster, C.G.

    2016-01-01

    The endospore is the dormant form of Bacillus subtilis and many other Firmicutes. By sporulation, these spore formers can survive very harsh physical and chemical conditions. Yet, they need to go through germination to return to their growing form. The spore inner membrane (IM) has been shown to

  7. What can spores do for us?

    NARCIS (Netherlands)

    Wolken, W.A.M.; Tramper, J.; Werf, van der M.J.

    2003-01-01

    Many organisms have the ability to form spores, a remarkable phase in their life cycles. Compared with vegetative cells, spores have several advantages (e.g. resistance to toxic compounds, temperature, desiccation and radiation) making them well suited to various applications. The applications of

  8. Ptaquiloside in bracken spores from Britain.

    Science.gov (United States)

    Rasmussen, Lars Holm; Schmidt, Bjørn; Sheffield, Elizabeth

    2013-03-01

    Secondary metabolites from bracken fern (Pteridium aquilinum (L.) Kuhn) are suspected of causing cancer in humans. The main carcinogen is the highly water-soluble norsesquiterpene glucoside ptaquiloside, which may be ingested by humans through food, e.g. via contaminated water, meat or milk. It has been postulated that carcinogens could also be ingested through breathing air containing bracken spores. Ptaquiloside has not previously been identified in bracken spores. The aim of the study was to determine whether ptaquiloside is present in bracken spores, and if so, to estimate its content in a collection of spores from Britain. Ptaquiloside was present in all samples, with a maximum of 29 μg g(-1), which is very low compared to other parts of the fern. Considering the low abundance of spores in breathing air under normal conditions, this exposure route is likely to be secondary to milk or drinking water. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Influence of temperature on the formation and encapsulation of gold nanoparticles using a temperature-sensitive template

    Directory of Open Access Journals (Sweden)

    Noel Peter Bengzon Tan

    2015-12-01

    Full Text Available This data article describes the synthesis of temperature-sensitive and amine-rich microgel particle as a dual reductant and template to generate smart gold/polymer nanocomposite particle. TEM images illustrate the influence of reaction temperature on the formation and in-site encapsulation of gold nanoparticles using the temperature-sensitive microgel template. Thermal stability of the resultant gold/polymer composite particles was also examined.

  10. Examining the Physical Drivers of Photosynthetic Temperature Sensitivity Within a Sub-alpine Mixed Conifer Forest

    Science.gov (United States)

    Yang, J.; Barron-Gafford, G.; Minor, R.; Heard, M.

    2013-12-01

    Current projections of climate change in the southwestern U.S. suggest increasing temperatures and reduced summer precipitation. High temperature and water deficits have major influence on ecosystem functioning by restricting plant growth and productivity. However, there are limited data on what influences plant sensitivity to temperature, and these dynamics are not often captured in ecosystem models. Understanding the sensitivities, linkages, and feedbacks among biotic processes and abiotic forces is especially important within Critical Zone Sciences, which seeks to integrate among disciplines. Here, we analyzed several potential drivers of photosynthetic temperature sensitivity, including differences in soil parent material, aspect, and seasonality within a suite of species. Each of these variables captures a different physical driver: (i) soil parent material influences water holding capacity of the soil; (ii) aspect influences how incoming energy drives evaporative loss of soil water, creating warmer and drier environments on south/east faces; and (iii) seasonality captures temporal patterns of soil moisture recharge. Our research was conducted within two V shaped zero-order catchment basins of the Santa Catalina Critical Zone Observatory in southern Arizona, one with schist bedrock and the other with granite. We used leaf-level gas exchange measurements on 24 trees across a range of temperatures to quantify this plant temperature sensitivity during the dry pre-monsoon and wet monsoon seasons. Preliminary results show that maximum photosynthetic rate was 51% higher during the monsoon than pre-monsoon season. Optimal photosynthetic temperature decreased 25% while the span of functional temperatures (Ω50) was 21% higher following the onset of monsoon rains. During the rainy season, soil parent material became an important factor. The greater water holding capacity of schist soils yielded greater maximum photosynthesis and reduced tree sensitivity to higher

  11. Global synthesis of the temperature sensitivity of leaf litter breakdown in streams and rivers.

    Science.gov (United States)

    Follstad Shah, Jennifer J; Kominoski, John S; Ardón, Marcelo; Dodds, Walter K; Gessner, Mark O; Griffiths, Natalie A; Hawkins, Charles P; Johnson, Sherri L; Lecerf, Antoine; LeRoy, Carri J; Manning, David W P; Rosemond, Amy D; Sinsabaugh, Robert L; Swan, Christopher M; Webster, Jackson R; Zeglin, Lydia H

    2017-08-01

    Streams and rivers are important conduits of terrestrially derived carbon (C) to atmospheric and marine reservoirs. Leaf litter breakdown rates are expected to increase as water temperatures rise in response to climate change. The magnitude of increase in breakdown rates is uncertain, given differences in litter quality and microbial and detritivore community responses to temperature, factors that can influence the apparent temperature sensitivity of breakdown and the relative proportion of C lost to the atmosphere vs. stored or transported downstream. Here, we synthesized 1025 records of litter breakdown in streams and rivers to quantify its temperature sensitivity, as measured by the activation energy (E a , in eV). Temperature sensitivity of litter breakdown varied among twelve plant genera for which E a could be calculated. Higher values of E a were correlated with lower-quality litter, but these correlations were influenced by a single, N-fixing genus (Alnus). E a values converged when genera were classified into three breakdown rate categories, potentially due to continual water availability in streams and rivers modulating the influence of leaf chemistry on breakdown. Across all data representing 85 plant genera, the E a was 0.34 ± 0.04 eV, or approximately half the value (0.65 eV) predicted by metabolic theory. Our results indicate that average breakdown rates may increase by 5-21% with a 1-4 °C rise in water temperature, rather than a 10-45% increase expected, according to metabolic theory. Differential warming of tropical and temperate biomes could result in a similar proportional increase in breakdown rates, despite variation in E a values for these regions (0.75 ± 0.13 eV and 0.27 ± 0.05 eV, respectively). The relative proportions of gaseous C loss and organic matter transport downstream should not change with rising temperature given that E a values for breakdown mediated by microbes alone and microbes plus detritivores were similar at the

  12. Assessment of the use of temperature-sensitive microchips to determine core body temperature in goats.

    Science.gov (United States)

    Torrao, N A; Hetem, R S; Meyer, L C R; Fick, L G

    2011-03-26

    Body temperature was measured at five different body sites (retroperitoneum, groin, semimembranosus muscle, flank and shoulder) using temperature-sensitive microchips implanted in five female goats, and compared with the core body and rectal temperatures. Body temperature was measured while the goats were kept in different ambient temperatures, with and without radiant heat, as well as during a fever induced experimentally by injection of bacterial lipopolysaccharide. Bland-Altman limit of agreement analysis was used to compare the temperature measurements at the different body sites during the different interventions. Temperatures measured by the microchip implanted in the retroperitoneum showed the closest agreement (mean 0.2 °C lower) with core and rectal temperatures during all interventions, whereas temperatures measured by the microchips implanted in the groin, muscle, flank and shoulder differed from core body temperature by up to 3.5 °C during the various interventions.

  13. A TEMPERATURE-SENSITIVE STREPTOMYCIN REQUIREMENT IN AN ESCHERICHIA COLI MUTANT

    Science.gov (United States)

    Plunkett, Geoffrey E.

    1962-01-01

    Plunkett, Geoffrey E. (Biochemical Research Foundation, Newark, Del.). A temperature-sensitive streptomycin requirement in an Escherichia coli mutant. J. Bacteriol. 84:275–277. 1962.—A strain of Escherichia coli, streptomycin-dependent at 37.5 C, has been found to be capable of continuing cell division in the absence of streptomycin when incubated at 31 C. This property appeared to be heritable and persisted after repeated single-colony isolations from streptomycin-containing agar maintained at 37.5 C, or from streptomycin-free agar maintained at 31 C. The cells were stored under refrigeration on streptomycin-free agar slants, and retained their requirement for streptomycin when returned to 37.5 C after more than 7 months in its absence at lower temperatures. PMID:14487264

  14. Greater temperature sensitivity of plant phenology at colder sites: implications for convergence across northern latitudes.

    Science.gov (United States)

    Prevéy, Janet; Vellend, Mark; Rüger, Nadja; Hollister, Robert D; Bjorkman, Anne D; Myers-Smith, Isla H; Elmendorf, Sarah C; Clark, Karin; Cooper, Elisabeth J; Elberling, Bo; Fosaa, Anna M; Henry, Gregory H R; Høye, Toke T; Jónsdóttir, Ingibjörg S; Klanderud, Kari; Lévesque, Esther; Mauritz, Marguerite; Molau, Ulf; Natali, Susan M; Oberbauer, Steven F; Panchen, Zoe A; Post, Eric; Rumpf, Sabine B; Schmidt, Niels M; Schuur, Edward A G; Semenchuk, Phillip R; Troxler, Tiffany; Welker, Jeffrey M; Rixen, Christian

    2017-07-01

    Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up to 20 years of phenology data for 47 tundra plant species at 18 high-latitude sites along a climatic gradient. Across all species, the timing of leaf emergence and flowering was more sensitive to a given increase in summer temperature at colder than warmer high-latitude locations. A similar pattern was seen over time for the flowering phenology of a widespread species, Cassiope tetragona. These are among the first results highlighting differential phenological responses of plants across a climatic gradient and suggest the possibility of convergence in flowering times and therefore an increase in gene flow across latitudes as the climate warms. © 2017 John Wiley & Sons Ltd.

  15. Phenotype of a Temperature-Sensitive, Respiration-Deficient (cyt) Mutant of Yeast

    Science.gov (United States)

    Miyake, Setsuko; Iwamoto, Yoshihisa; Nagao, Minako; Sugimura, Takashi; Ohsumi, Masako

    1972-01-01

    A temperature-sensitive respiration-deficient mutant of yeast lacks hemoproteins and accumulates coproporphyrin III when cultivated at elevated temperatures. Cells grown at 20 C respired normally and contained cytochromes a, b, and c. Cells grown at 35 C showed respiration-deficient mutant characters; they did not respire, lacked cytochromes, and accumulated coproporphyrin III. Addition of protoporphyrin IX or protohemin IX to the culture medium restored the respiratory activity of this mutant during growth at 35 C. The activities of various enzymes, including succinate-2,6-dichlorophenol indophenol (DCPIP), reduced nicotinamide adenine dinucleotide (NADH2)-DCPIP, succinate-cytochrome c, and NADH2-cytochrome c oxidoreductase, and cytochrome oxidase, and the cytochrome c content of cells cultured in various conditions were determined. Changes in the number and structure of mitochondria were associated with changes in respiratory activity. Images PMID:4333381

  16. THERMOGRAPHIC APPLICATIONS OF TEMPERATURE SENSITIVE FLUORESCENCE OF SrS:Cu PHOSPHORS

    Directory of Open Access Journals (Sweden)

    R. PUROHIT

    2010-12-01

    Full Text Available The present work aims at investigating the temperature sensitive fluoro-optic behaviour of Cu-activated strontium sulphide (SrS phosphors and its possible application in thermography. Accordingly, SrS (Cu phosphors have been synthesized and painted with the help of adhesive on silica substrate. The excitation and emission spectra of such phosphor coatings have been recorded at room temperature (25C. The temperature dependence of fluorescence intensity and the lifetime of phosphorescence have also been studied. From the systematic variation of these two parameters with temperature, it appears that these phosphors are good candidates for thermographic application, at least, in the temperature range of investigation (25-150C.

  17. Effect of thermal aging on stability of transformer oil based temperature sensitive magnetic fluids

    Science.gov (United States)

    Kaur, Navjot; Chudasama, Bhupendra

    2018-04-01

    Synthesizing stable temperature sensitive magnetic fluids with tunable magnetic properties that can be used as coolant in transformers is of great interest, however not exploited commercially due to the lack of its stability at elevated temperatures in bulk quantities. The task is quite challenging as the performance parameters of magnetic fluids are strongly influenced by thermal aging. In this article, we report the effect of thermal aging on colloidal stability and magnetic properties of Mn1-xZnxFe2O4 magnetic fluids prepared in industrial grade transformer oil. As-synthesized magnetic fluids possess good dispersion stability and tunable magnetic properties. Effect of accelerated thermal aging on the dispersion stability and magnetic properties have been evaluated by photon correlation spectroscopy and vibration sample magnetometry, respectively. Magnetic fluids are stable under accelerated aging at elevated temperatures (from 50 °C to 125 °C), which is critical for their efficient performance in high power transformers.

  18. Temperature sensitivity of decomposition in relation to soil organic matter pools: critique and outlook

    Directory of Open Access Journals (Sweden)

    M. Reichstein

    2005-01-01

    Full Text Available Knorr et al. (2005 concluded that soil organic carbon pools with longer turnover times are more sensitive to temperature. We show that this conclusion is equivocal, largely dependent on their specific selection of data and does not persist when the data set of Kätterer et al. (1998 is analysed in a more appropriate way. Further, we analyse how statistical properties of the model parameters may interfere with correlative analyses that relate the Q10 of soil respiration with the basal rate, where the latter is taken as a proxy for soil organic matter quality. We demonstrate that negative parameter correlations between Q10-values and base respiration rates are statistically expected and not necessarily provide evidence for a higher temperature sensitivity of low quality soil organic matter. Consequently, we propose it is premature to conclude that stable soil carbon is more sensitive to temperature than labile carbon.

  19. Immunolocalization and distribution of functional temperature-sensitive TRP channels in salivary glands.

    Science.gov (United States)

    Sobhan, Ubaidus; Sato, Masaki; Shinomiya, Takashi; Okubo, Migiwa; Tsumura, Maki; Muramatsu, Takashi; Kawaguchi, Mitsuru; Tazaki, Masakazu; Shibukawa, Yoshiyuki

    2013-11-01

    Transient receptor potential (TRP) cation channels are unique cellular sensors involved in multiple cellular functions. Their role in salivary secretion remains to be elucidated. The expression and localization of temperature-sensitive TRP channels in salivary (submandibular, sublingual and parotid) glands were analyzed by immunohistochemistry and quantitative real-time reverse transcription plus the polymerase chain reaction (RT-PCR). The effects of various TRP channel agonists on carbachol (CCh)-induced salivary secretion in the submandibular gland and on the intracellular Ca(2+) concentration ([Ca(2+)]i) in a submandibular epithelial cell line were also investigated. Immunohistochemistry revealed the expression of TRP-melastatin subfamily member 8 (TRPM8) and TRP-ankyrin subfamily member 1 (TRPA1) in myoepithelial, acinar and ductal cells in the sublingual, submandibular and parotid glands. In addition, TRP-vanilloid subfamily member 1 (TRPV1), TRPV3 and TRPV4 were also expressed in myoepithelial, acinar and ductal cells in all three types of gland. Quantitative real-time RT-PCR results demonstrated the mRNA expression of TRPV1, TRPV3, TRPV4, TRPM8 and TRPA1 in acinar and ductal cells in these salivary glands. Perfusion of the entire submandibular gland with the TRPV1 agonist capsaicin (1 μM) via the submandibular artery significantly increased CCh-induced salivation, whereas perfusion with TRPM8 and TRPA1 agonists (0.5 μM WS12 and 100 μM allyl isothiocyanate) decreased it. Application of agonists for each of the thermosensitive TRP channels increased [Ca(2+)]i in a submandibular epithelial cell line. These results indicate that temperature-sensitive TRP channels are localized and distributed in acinar, ductal and myoepithelial cells in salivary glands and that they play a functional role in the regulation and/or modulation of salivary secretion.

  20. Variations in the temperature sensitivity of spring leaf phenology from 1978 to 2014 in Mudanjiang, China

    Science.gov (United States)

    Dai, Junhu; Xu, Yunjia; Wang, Huanjiong; Alatalo, Juha; Tao, Zexing; Ge, Quansheng

    2017-12-01

    Continuous long-term temperature sensitivity (ST) of leaf unfolding date (LUD) and main impacting factors in spring in the period 1978-2014 for 40 plant species in Mudanjiang, Heilongjiang Province, Northeast China, were analyzed by using observation data from the China Phenological Observation Network (CPON), together with the corresponding meteorological data from the China Meteorological Data Service Center. Temperature sensitivities, slopes of the regression between LUD and mean temperature during the optimum preseason (OP), were analyzed using 15-year moving window to determine their temporal trends. Major factors impacting ST were then chosen and evaluated by applying a random sampling method. The results showed that LUD was sensitive to mean temperature in a defined period before phenophase onset for all plant species analyzed. Over the period 1978-2014, the mean ST of LUD for all plant species was - 3.2 ± 0.49 days °C-1. The moving window analysis revealed that 75% of species displayed increasing ST of LUD, with 55% showing significant increases (P < 0.05). ST for the other 25% exhibited a decreasing trend, with 17% showing significant decreases (P < 0.05). On average, ST increased by 16%, from - 2.8 ± 0.83 days °C-1 during 1980-1994 to - 3.30 ± 0.65 days °C-1 during 2000-2014. For species with later LUD and longer OP, ST tended to increase more, while species with earlier LUD and shorter OP tended to display a decreasing ST. The standard deviation of preseason temperature impacted the temporal variation in ST. Chilling conditions influenced ST for some species, but photoperiod limitation did not have significant or coherent effects on changes in ST.

  1. Temperature sensitivity of microbial respiration of fine root litter in a temperate broad-leaved forest.

    Science.gov (United States)

    Makita, Naoki; Kawamura, Ayumi

    2015-01-01

    The microbial decomposition respiration of plant litter generates a major CO2 efflux from terrestrial ecosystems that plays a critical role in the regulation of carbon cycling on regional and global scales. However, the respiration from root litter decomposition and its sensitivity to temperature changes are unclear in current models of carbon turnover in forest soils. Thus, we examined seasonal changes in the temperature sensitivity and decomposition rates of fine root litter of two diameter classes (0-0.5 and 0.5-2.0 mm) of Quercus serrata and Ilex pedunculosa in a deciduous broad-leaved forest. During the study period, fine root litter of both diameter classes and species decreased approximately exponentially over time. The Q10 values of microbial respiration rates of root litter for the two classes were 1.59-3.31 and 1.28-6.27 for Q. serrata and 1.36-6.31 and 1.65-5.86 for I. pedunculosa. A significant difference in Q10 was observed between the diameter classes, indicating that root diameter represents the initial substrate quality, which may determine the magnitude of Q10 value of microbial respiration. Changes in these Q10 values were related to seasonal soil temperature patterns; the values were higher in winter than in summer. Moreover, seasonal variations in Q10 were larger during the 2-year decomposition period than the 1-year period. These results showed that the Q10 values of fine root litter of 0-0.5 and 0.5-2.0 mm have been shown to increase with lower temperatures and with the higher recalcitrance pool of the decomposed substrate during 2 years of decomposition. Thus, the temperature sensitivity of microbial respiration in root litter showed distinct patterns according to the decay period and season because of the temperature acclimation and adaptation of the microbial decomposer communities in root litter.

  2. Regional variation in the temperature sensitivity of soil organic matter decomposition in China's forests and grasslands.

    Science.gov (United States)

    Liu, Yuan; He, Nianpeng; Zhu, Jianxing; Xu, Li; Yu, Guirui; Niu, Shuli; Sun, Xiaomin; Wen, Xuefa

    2017-08-01

    How to assess the temperature sensitivity (Q 10 ) of soil organic matter (SOM) decomposition and its regional variation with high accuracy is one of the largest uncertainties in determining the intensity and direction of the global carbon (C) cycle in response to climate change. In this study, we collected a series of soils from 22 forest sites and 30 grassland sites across China to explore regional variation in Q 10 and its underlying mechanisms. We conducted a novel incubation experiment with periodically changing temperature (5-30 °C), while continuously measuring soil microbial respiration rates. The results showed that Q 10 varied significantly across different ecosystems, ranging from 1.16 to 3.19 (mean 1.63). Q 10 was ordered as follows: alpine grasslands (2.01) > temperate grasslands (1.81) > tropical forests (1.59) > temperate forests (1.55) > subtropical forests (1.52). The Q 10 of grasslands (1.90) was significantly higher than that of forests (1.54). Furthermore, Q 10 significantly increased with increasing altitude and decreased with increasing longitude. Environmental variables and substrate properties together explained 52% of total variation in Q 10 across all sites. Overall, pH and soil electrical conductivity primarily explained spatial variation in Q 10 . The general negative relationships between Q 10 and substrate quality among all ecosystem types supported the C quality temperature (CQT) hypothesis at a large scale, which indicated that soils with low quality should have higher temperature sensitivity. Furthermore, alpine grasslands, which had the highest Q 10 , were predicted to be more sensitive to climate change under the scenario of global warming. © 2017 John Wiley & Sons Ltd.

  3. Seasonal variation in the temperature sensitivity of proteolytic enzyme activity in temperate forest soils

    Science.gov (United States)

    Brzostek, Edward R.; Finzi, Adrien C.

    2012-03-01

    Increasing soil temperature has the potential to alter the activity of the extracellular enzymes that mobilize nitrogen (N) from soil organic matter (SOM) and ultimately the availability of N for primary production. Proteolytic enzymes depolymerize N from proteinaceous components of SOM into amino acids, and their activity is a principal driver of the within-system cycle of soil N. The objectives of this study were to investigate whether the soils of temperate forest tree species differ in the temperature sensitivity of proteolytic enzyme activity over the growing season and the role of substrate limitation in regulating temperature sensitivity. Across species and sampling dates, proteolytic enzyme activity had relatively low sensitivity to temperature with a mean activation energy (Ea) of 33.5 kJ mol-1. Ea declined in white ash, American beech, and eastern hemlock soils across the growing season as soils warmed. By contrast, Eain sugar maple soil increased across the growing season. We used these data to develop a species-specific empirical model of proteolytic enzyme activity for the 2009 calendar year and studied the interactive effects of soil temperature (ambient or +5°C) and substrate limitation (ambient or elevated protein) on enzyme activity. Declines in substrate limitation had a larger single-factor effect on proteolytic enzyme activity than temperature, particularly in the spring. There was, however, a large synergistic effect of increasing temperature and substrate supply on proteolytic enzyme activity. Our results suggest limited increases in N availability with climate warming unless there is a parallel increase in the availability of protein substrates.

  4. Temperature sensitivity of soil organic carbon decomposition increased with mean carbon residence time: Field incubation and data assimilation.

    Science.gov (United States)

    Zhou, Xuhui; Xu, Xia; Zhou, Guiyao; Luo, Yiqi

    2018-02-01

    Temperature sensitivity of soil organic carbon (SOC) decomposition is one of the major uncertainties in predicting climate-carbon (C) cycle feedback. Results from previous studies are highly contradictory with old soil C decomposition being more, similarly, or less sensitive to temperature than decomposition of young fractions. The contradictory results are partly from difficulties in distinguishing old from young SOC and their changes over time in the experiments with or without isotopic techniques. In this study, we have conducted a long-term field incubation experiment with deep soil collars (0-70 cm in depth, 10 cm in diameter of PVC tubes) for excluding root C input to examine apparent temperature sensitivity of SOC decomposition under ambient and warming treatments from 2002 to 2008. The data from the experiment were infused into a multi-pool soil C model to estimate intrinsic temperature sensitivity of SOC decomposition and C residence times of three SOC fractions (i.e., active, slow, and passive) using a data assimilation (DA) technique. As active SOC with the short C residence time was progressively depleted in the deep soil collars under both ambient and warming treatments, the residences times of the whole SOC became longer over time. Concomitantly, the estimated apparent and intrinsic temperature sensitivity of SOC decomposition also became gradually higher over time as more than 50% of active SOC was depleted. Thus, the temperature sensitivity of soil C decomposition in deep soil collars was positively correlated with the mean C residence times. However, the regression slope of the temperature sensitivity against the residence time was lower under the warming treatment than under ambient temperature, indicating that other processes also regulated temperature sensitivity of SOC decomposition. These results indicate that old SOC decomposition is more sensitive to temperature than young components, making the old C more vulnerable to future warmer

  5. Detection limit of Clostridium botulinum spores in dried mushroom samples sourced from China.

    Science.gov (United States)

    Malakar, Pradeep K; Plowman, June; Aldus, Clare F; Xing, Zengtao; Zhao, Yong; Peck, Michael W

    2013-08-16

    A survey of dried mushrooms (Lentinula edodes (Shiitake) and Auricularia auricula (Wood Ear)) sourced from China was carried out to determine the natural contamination of these mushrooms with spores of proteolytic Clostridium botulinum and non-proteolytic C. botulinum. The mushrooms were collected from supermarkets and retailers in 21 cities in China during October 2008. Spore loads of C. botulinum in mushrooms have a degree of uncertainty and variability and this study contributes valuable data for determining prevalence of spores of C. botulinum in mushrooms. An optimized detection protocol that combined selective enrichment culture with multiplex PCR was used to test for spores of proteolytic and non-proteolytic C. botulinum. Detection limits were calculated, using a maximum likelihood protocol, from mushroom samples inoculated with defined numbers of spores of proteolytic C. botulinum or non-proteolytic C. botulinum. Based on the maximum likelihood detection limit, it is estimated that dried mushroom A. auricula contained botulinum, and botulinum. Dried L. edodes contained botulinum and it was not possible to determine reliable detection limits for spores of non-proteolytic C. botulinum using the current detection protocol. © 2013 Elsevier B.V. All rights reserved.

  6. Mechanism and site of inhibition of Bacillus cereus spore outgrowth by nitrosothiols

    International Nuclear Information System (INIS)

    Morris, S.L.

    1982-01-01

    Structure vs. activity studies demonstrate that nitrosothiols inhibit outgrowth of B. cereus spores by reversible covalent bond formation with sensitive spore components. Kinetic studies of the binding of nitrosothiols and iodoacetate, a known sulfhydryl reagent, show that they complete for the same spore sites. Since two other nitrite derivatives, the Perigo factor and the transferrin inhibitor, interfere with iodoacetate label uptake in a kinetically similar fashion, all of these compounds may inhibit spore outgrowth by interacting with the same spore thiol groups. Disruption of spores which have been inhibited by radioactive iodoacetate demonstrates that much of the label is incorporated into a membrane-rich fraction that sediments as a single peak on a sucrose density gradient. SDS gel electrophoresis and autofluorography allows the identification of four intensely labelled proteins with molecular weights of 13,000, 28,000, 29,000, and 30,000. If the iodoacetate labelling is carried out in the presence of nitrosothiol, incorporation is greatly reduced into all components. When germinating spores are labelled with succinate or the lactose analog, o-nitrophenylgalactopyranoside, a significant reduction in the amount of label bound is also observed suggesting that two iodoacetate-reactive sites may be the succinate and lactose permease systems. Severe decreases in the transport of succinate and lactose into iodoacetate and nitrosothiol inhibited spores further implicates a nitrosothiol (iodoacetate) permease interaction. Iodoacetate and nitrosothiols therefore may exert their inhibitory effects by interfering with critical membrane protein sulfhydryl groups, possibly by a a covalent modification mechanism. Some of these sensitive thiols may be involved in active transport processes

  7. Temperature sensitivity of wormlike micelles in poly(oxyethylene) surfactant solution: importance of hydrophilic-group size.

    Science.gov (United States)

    Ahmed, Toufiq; Aramaki, Kenji

    2009-08-01

    We have studied the temperature sensitivity of the rheology of the wormlike micellar solutions formed in poly(oxyethylene) cholesteryl ether (ChEO(m), m=15 and 30) upon addition of tri(ethyleneglycol) mono n-dodecyl ether (C(12)EO(3)) and monolaurin. We have found that increasing the poly(oxyethylene) chain length of ChEO(m) greatly reduces the temperature-sensitivity of the viscosity of the solution. In the viscous region small changes in the cosurfactant composition can subtly change the temperature sensitivity depending on the temperature range and type of cosurfactant. For, C(12)EO(3), which is a poly(oxyethylene) surfactant, the temperature sensitivity is lower at lower temperatures and higher at higher temperatures if the cosurfactant mixing fraction is high and vice versa if the mixing fraction is low. For monolaurin, the temperature sensitivity increases with cosurfactant mixing fraction in the viscous region. In the ChEO(30)-monolaurin system viscous solutions are not formed at any temperature that we studied. We have discussed these results in terms of the reduction of the average curvature of micellar interface with temperature due to dehydration of the poly(oxyethylene) chain and formation of branches in long micelles. We indicate the scientific and technical significance of our findings.

  8. Sensitivity of thermally treated Bacillus subtilis spores to subsequent irradiation

    International Nuclear Information System (INIS)

    Mostafa, S.A.; El-Zawahry, Y.A.; Awny, N.M.

    1986-01-01

    B. subtilis spores exposed to thermal treatment at 70 or 80 0 C for 1 hr were more sensitive to subsequent radiation exposure than non-heated spores. Deactivation of previously heated spores by increasing dose of 0-radiation followed an exponential function while, for non-heated spores a shoulder followed by exponential deactivation was noticed. Combined heat-radiation treatment exhibited a synergistic effect on spore deactivation at low irradiation doses, while at high irradiation doses, the effect was more or less additive. Added values of spore injury was higher for B. subtilis spores that received heat and radiation separately than the observed injury for spores that received combined treatment (heat followed by radiation). Results of spore deactivation and injury due to heat followed by radiation treatment are discussed in comparison to those of spores that received radiation-heat sequence

  9. Linking temperature sensitivity of soil organic matter decomposition to its molecular structure, accessibility, and microbial physiology.

    Science.gov (United States)

    Wagai, Rota; Kishimoto-Mo, Ayaka W; Yonemura, Seiichiro; Shirato, Yasuhito; Hiradate, Syuntaro; Yagasaki, Yasumi

    2013-04-01

    Temperature sensitivity of soil organic matter (SOM) decomposition may have a significant impact on global warming. Enzyme-kinetic hypothesis suggests that decomposition of low-quality substrate (recalcitrant molecular structure) requires higher activation energy and thus has greater temperature sensitivity than that of high-quality, labile substrate. Supporting evidence, however, relies largely on indirect indices of substrate quality. Furthermore, the enzyme-substrate reactions that drive decomposition may be regulated by microbial physiology and/or constrained by protective effects of soil mineral matrix. We thus tested the kinetic hypothesis by directly assessing the carbon molecular structure of low-density fraction (LF) which represents readily accessible, mineral-free SOM pool. Using five mineral soil samples of contrasting SOM concentrations, we conducted 30-days incubations (15, 25, and 35 °C) to measure microbial respiration and quantified easily soluble C as well as microbial biomass C pools before and after the incubations. Carbon structure of LFs (soil was measured by solid-state (13) C-NMR. Decomposition Q10 was significantly correlated with the abundance of aromatic plus alkyl-C relative to O-alkyl-C groups in LFs but not in bulk soil fraction or with the indirect C quality indices based on microbial respiration or biomass. The warming did not significantly change the concentration of biomass C or the three types of soluble C despite two- to three-fold increase in respiration. Thus, enhanced microbial maintenance respiration (reduced C-use efficiency) especially in the soils rich in recalcitrant LF might lead to the apparent equilibrium between SOM solubilization and microbial C uptake. Our results showed physical fractionation coupled with direct assessment of molecular structure as an effective approach and supported the enzyme-kinetic interpretation of widely observed C quality-temperature relationship for short-term decomposition. Factors

  10. Development of bioprocess for high density cultivation yield of the probiotic Bacillus coagulans and its spores

    Directory of Open Access Journals (Sweden)

    Kavita R. Pandey

    2016-09-01

    Full Text Available Bacillus coagulans is a spore forming lactic acid bacterium. Spore forming bacteria, have been extensively studied and commercialized as probiotics. Probiotics are produced by fermentation technology. There is a limitation to biomass produced by conventional modes of fermentation. With the great demand generated by range of probiotic products, biomass is becoming very valuable for several pharmaceutical, dairy and probiotic companies. Thus, there is a need to develop high cell density cultivation processes for enhanced biomass accumulation. The bioprocess development was carried out in 6.6 L bench top lab scale fermentor. Four different cultivation strategies were employed to develop a bioprocess for higher growth and sporulation efficiencies of probiotic B. coagulans. Batch fermentation of B. coagulans yielded 18 g L-1 biomass (as against 8.0 g L-1 productivity in shake flask with 60% spore efficiency. Fed-batch cultivation was carried out for glucose, which yielded 25 g L-1 of biomass. C/N ratio was very crucial in achieving higher spore titres. Maximum biomass yield recorded was 30 g L-1, corresponding to 3.8 × 1011 cells mL-1 with 81% of cells in sporulated stage. The yield represents increment of 85 times the productivity and 158 times the spore titres relative to the highest reported values for high density cultivation of B. coagulans.

  11. Differential chromosomal and mitochondrial DNA synthesis in temperature-sensitive mutants of Ustilago maydis

    Energy Technology Data Exchange (ETDEWEB)

    Unrau, P.

    1977-01-01

    The amount and type of residual DNA synthesis was determined in eight temperature-sensitive mutants of the smut fungus Ustilago maydis after incubation at the restrictive temperature (32/sup 0/C) for eight hours. Mutants ts-220, ts-207, ts-432 and ts-346 were found to have an overall reduction in the synthesis of both nuclear and mitochondrial DNA in comparison to the wild-type. In mutants ts-20, tsd 1-1, ts-84 and pol 1-1 nuclear DNA synthesis was depressed relative to mitochondrial synthesis. The DNA-polymerase mutant pol 1-1 had persistent nuclear synthesis at about 50% of the rate of synthesis of mitochondrial DNA and similar behavior was observed in a diploid homozygous strain. Mutant ts-84 had an initial burst of DNA synthesis which was reduced for nuclear but not mitochondrial synthesis after three hours preincubation at 32/sup 0/C. tsd 1-1 and ts-20 had nuclear residual synthesis amounting to about 25% of the relative rate of mitochondrial synthesis which correlates to increasing UV sensitivity of these strains on incubation at 32/sup 0/C. A pol 1-1 ts-84 double mutant had an additive loss of nuclear DNA synthesis which indicates that the steps of replication involved may be sequential.

  12. UV-B-inducible and temperature-sensitive photoreactivation of cyclobutane pyrimidine dimers in Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Pang, Qishen; Hays, J.B.

    1991-01-01

    Removal of cyclobutane pyrimidine dimers (CBPDs) in vivo from the DNA of UV-irradiated eight-leaf seedlings of Arabidopsis thaliana was rapid in the presence of visible light (half-life about 1 hour); removal of CBPDs in the dark, presumably via excision repair, was an order of magnitude slower. Extracts of plants contained significant photolyase in vitro, as assayed by restoration of transforming activity to UV-irradiated Escherichia coli plasmids; activity was maximal from four-leaf to 12-leaf stages. UV-B treatment of seedlings for 6 hours increased photolyase specific activity in extracts twofold. Arabidopsis photolyase was markedly temperature-sensitive, both in vitro (half-life at 30C about 12 minutes) and in vivo (half-life at 30C, 30 to 45 minutes). The wavelength dependency of the photoreactivation cross-section showed a broad peak at 375 to 400 nm, and is thus similar to that for maize pollen; it overlaps bacterial and yeast photolyase action spectra

  13. Vanadium sesquioxide (V2O3)-based semiconducting temperature sensitive resistors for uncooled microbolometers

    Science.gov (United States)

    Abdel-Rahman, Mohamed; Alduraibi, Mohammad; Zia, Muhammad Fakhar; Bahidra, Esme; Alasaad, Amr

    2017-05-01

    This paper reports on a semiconducting resistor material based on vanadium sesquioxide (V2O3) with electrical resistivity and temperature coefficient of resistance (TCR) appropriate for microbolometer applications. In this work, V2O3-based semiconducting resistor material was synthesized and electrically characterized. The developed material was prepared by annealing, in O2 and N2 atmospheres, a cascaded multilayer structure composed of V2O3 (10 nm) and V (5 nm) room temperature sputter coated thin films. The developed 55 nm thin film microbolometer resistor material possessed high temperature sensitivity from 20∘C to 45∘C with a TCR of -3.68%/∘C and room temperature resistivity of 0.57 Ω ṡcm for O2 annealed samples and a TCR of -3.72%/∘C and room temperature resistivity of 0.72 Ω ṡcm for N2 annealed samples. The surface morphologies of the synthesized thin films were studied using atomic force microscopy showing no significant post-growth annealing effect on the smoothness of the samples surfaces.

  14. An investigation of low temperature sensitization (LTS) in AISI 316 stainless steel

    International Nuclear Information System (INIS)

    Juhas, M.C.; Wilde, B.E.

    1988-01-01

    Type 316L stainless steel (SS) is among several alloys which are being extensively characterized as possible containment materials for high-level nuclear waste. The current reference design for the container is a seamless cylinder to which a lid is welded forming a permanent seal. Because post weld heat treatment is impractical in this situation, the heat affected zone (HAZ) may be susceptible to intergranular corrosion and possibly intergranular stress cracking in the event of intrusion by an oxidizing medium. The combination of the weld thermal cycle an prolonged exposure (more than 100 years) in the 200 0 C temperature regime renders the HAZ potentially susceptible to Low Temperature Sensitization (LTS). Stable M/sub 23/C/sub 6/ carbides have been shown to grow as a result of this combine heat treatment. The classical TTS curves are often reported based on electrochemical tests or thermodynamic models. In both cases, the material is considered to be sensitized when the grain boundary carbide has grown to the extent of substantial Cr depletion in the adjacent area (<0.13 mole fraction Cr). At this point, the carbides are usually visible using conventional electron microscopy techniques and the material is susceptible to intergranular corrosion in typical laboratory screening tests

  15. Temperature-sensitive high affinity [3H]serotonin binding: characterization and effects of antidepressant treatment

    International Nuclear Information System (INIS)

    Helmeste, D.M.; Tang, S.W.

    1984-01-01

    Characterization of temperature-sensitive [ 3 H]serotonin (5-HT) binding sites (1 and 4 nM Kd sites) revealed complex inhibition by neuroleptics and serotonin antagonists. There was no simple correlation with affinities for S 1 and S 2 receptors. In vivo pretreatment (48 h before) with mianserin did not alter B/sub max/ or Kd for the 1 nM Kd [ 3 H]5-HT site, although [ 3 H]ketanserin (S 2 ) densities were decreased by 50%. This suggested that possible S 2 components of [ 3 H]5-HT binding must be negligible, even though ketanserin competed with high affinity (IC 50 = 3 nM) for a portion of the 1 nM Kd [ 3 H]5-HT site. Low concentrations of mianserin inhibited the 1 nM Kd [ 3 H]5-HT site in a non-competitive manner, as shown by a decrease in B/sub max/ with no change in Kd after in vitro incubation. The complex inhibition data may therefore represent indirect interactions through another site

  16. Effect of soil moisture on the temperature sensitivity of Northern soils

    Science.gov (United States)

    Minions, C.; Natali, S.; Ludwig, S.; Risk, D.; Macintyre, C. M.

    2017-12-01

    Arctic and boreal ecosystems are vast reservoirs of carbon and are particularly sensitive to climate warming. Changes in the temperature and precipitation regimes of these regions could significantly alter soil respiration rates, impacting atmospheric concentrations and affecting climate change feedbacks. Many incubation studies have shown that both temperature and soil moisture are important environmental drivers of soil respiration; this relationship, however, has rarely been demonstrated with in situ data. Here we present the results of a study at six field sites in Alaska from 2016 to 2017. Low-power automated soil gas systems were used to measure soil surface CO2 flux from three forced diffusion chambers and soil profile concentrations from three soil depth chambers at hourly intervals at each site. HOBO Onset dataloggers were used to monitor soil moisture and temperature profiles. Temperature sensitivity (Q10) was determined at each site using inversion analysis applied over different time periods. With highly resolved data sets, we were able to observe the changes in soil respiration in response to changes in temperature and soil moisture. Through regression analysis we confirmed that temperature is the primary driver in soil respiration, but soil moisture becomes dominant beyond a certain threshold, suppressing CO2 flux in soils with high moisture content. This field study supports the conclusions made from previous soil incubation studies and provides valuable insights into the impact of both temperature and soil moisture changes on soil respiration.

  17. Differences in SOM decomposition and temperature sensitivity among soil aggregate size classes in a temperate grasslands.

    Science.gov (United States)

    Wang, Qing; Wang, Dan; Wen, Xuefa; Yu, Guirui; He, Nianpeng; Wang, Rongfu

    2015-01-01

    The principle of enzyme kinetics suggests that the temperature sensitivity (Q10) of soil organic matter (SOM) decomposition is inversely related to organic carbon (C) quality, i.e., the C quality-temperature (CQT) hypothesis. We tested this hypothesis by performing laboratory incubation experiments with bulk soil, macroaggregates (MA, 250-2000 μm), microaggregates (MI, 53-250 μm), and mineral fractions (MF, temperature and aggregate size significantly affected on SOM decomposition, with notable interactive effects (Psoil and soil aggregates increased with increasing incubation temperature in the following order: MA>MF>bulk soil >MI(P soil, MF, and MI. Similarly, the activation energies (Ea) for MA, bulk soil, MF, and MI were 48.47, 33.26, 27.01, and 23.18 KJ mol-1, respectively. The observed significant negative correlations between Q10 and C quality index in bulk soil and soil aggregates (Psoil aggregates. Cumulative C emission differed significantly among aggregate size classes (P temperature is closely associated withsoil aggregation and highlights the complex responses of ecosystem C budgets to future warming scenarios.

  18. Temperature sensitivity analysis of polarity controlled electrostatically doped tunnel field-effect transistor

    Science.gov (United States)

    Nigam, Kaushal; Pandey, Sunil; Kondekar, P. N.; Sharma, Dheeraj

    2016-09-01

    The conventional tunnel field-effect transistors (TFETs) have shown potential to scale down in sub-22 nm regime due to its lower sub-threshold slope and robustness against short-channel effects (SCEs), however, sensitivity towards temperature variation is a major concern. Therefore, for the first time, we investigate temperature sensitivity analysis of a polarity controlled electrostatically doped tunnel field-effect transistor (ED-TFET). Different performance metrics and analog/RF figure-of-merits were considered and compared for both devices, and simulations were performed using Silvaco ATLAS device tool. We found that the variation in ON-state current in ED-TFET is almost temperature independent due to electrostatically doped mechanism, while, it increases in conventional TFET at higher temperature. Above room temperature, the variation in ION, IOFF, and SS sensitivity in ED-TFET are only 0.11%/K, 2.21%/K, and 0.63%/K, while, in conventional TFET the variations are 0.43%/K, 2.99%/K, and 0.71%/K, respectively. However, below room temperature, the variation in ED-TFET ION is 0.195%/K compared to 0.27%/K of conventional TFET. Moreover, it is analysed that the incomplete ionization effect in conventional TFET severely affects the drive current and the threshold voltage, while, ED-TFET remains unaffected. Hence, the proposed ED-TFET is less sensitive towards temperature variation and can be used for cryogenics as well as for high temperature applications.

  19. An investigation on die crack detection using Temperature Sensitive Parameter for high speed LED mass production

    Science.gov (United States)

    Annaniah, Luruthudass; Devarajan, Mutharasu; San, Teoh Kok

    To ensure the highest quality & long-term reliability of LED components it is necessary to examine LED dice that have sustained mechanical damage during the manufacturing process. This paper has demonstrated that detection of die crack in mass manufactured LEDs can be achieved by measuring Temperature Sensitive Parameters (TSPs) during final testing. A newly-designed apparatus and microcontroller was used for this investigation in order to achieve the millisecond switching time needed for detecting thermal transient effects and at the same time meet the expected speed for mass manufacturing. Evaluations conducted at lab scale shows that thermal transient behaviour of cracked die is significantly different than that of an undamaged die. Having an established test limits to differentiate cracked dice, large volume tests in a production environment were used to confirm the effectiveness of this test method. Failure Bin Analysis (FBA) of this high volume experiment confirmed that all the cracked die LEDs were detected and the undamaged LEDs passed this test without over-rejection. The work verifies that tests based on TSP are effective in identifying die cracks and it is believed that the method could be extended to other types of rejects that have thermal transient signatures such as die delamination.

  20. Heterogeneity of carbon loss and its temperature sensitivity in East-European subarctic tundra soils.

    Science.gov (United States)

    Diáková, Kateřina; Čapek, Petr; Kohoutová, Iva; Mpamah, Promise A; Bárta, Jiří; Biasi, Christina; Martikainen, Pertti J; Šantrůčková, Hana

    2016-09-01

    Arctic peatlands store large stocks of organic carbon which are vulnerable to the climate change but their fate is uncertain. There is increasing evidence that a part of it will be lost as a result of faster microbial mineralization. We studied the vulnerability of 3500-5900 years old bare peat uplifted from permafrost layers by cryogenic processes to the surface of an arctic peat plateau. We aimed to find biotic and abiotic drivers of CLOSS from old peat and compare them with those of adjacent, young vegetated soils of the peat plateau and mineral tundra. The soils were incubated in laboratory at three temperatures (4°C, 12°C and 20°C) and two oxygen levels (aerobic, anaerobic). CLOSS was monitored and soil parameters (organic carbon quality, nutrient availability, microbial activity, biomass and stoichiometry, and extracellular oxidative and hydrolytic enzyme pools) were determined. We found that CLOSS from the old peat was constrained by low microbial biomass representing only 0.22% of organic carbon. CLOSS was only slightly reduced by the absence of oxygen and exponentially increased with temperature, showing the same temperature sensitivity under both aerobic and anaerobic conditions. We conclude that carbon in the old bare peat is stabilized by a combination of physical, chemical and biological controls including soil compaction, organic carbon quality, low microbial biomass and the absence of plants. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Temperature Sensitivity of an Atomic Vapor Cell-Based Dispersion-Enhanced Optical Cavity

    Science.gov (United States)

    Myneni, K.; Smith, D. D.; Chang, H.; Luckay, H. A.

    2015-01-01

    Enhancement of the response of an optical cavity to a change in optical path length, through the use of an intracavity fast-light medium, has previously been demonstrated experimentally and described theoretically for an atomic vapor cell as the intracavity resonant absorber. This phenomenon may be used to enhance both the scale factor and sensitivity of an optical cavity mode to the change in path length, e.g. in gyroscopic applications. We study the temperature sensitivity of the on-resonant scale factor enhancement, S(sub o), due to the thermal sensitivity of the lower-level atom density in an atomic vapor cell, specifically for the case of the Rb-87 D(sub 2) transition. A semi-empirical model of the temperature-dependence of the absorption profile, characterized by two parameters, a(sub o)(T) and gamma(sub a)(T) allows the temperature-dependence of the cavity response, S(sub o)(T) and dS(sub o)/dT to be predicted over a range of temperature. We compare the predictions to experiment. Our model will be useful in determining the useful range for S(sub o), given the practical constraints on temperature stability for an atomic vapor cell.

  2. Human body temperature and new approaches to constructing temperature-sensitive bacterial vaccines.

    Science.gov (United States)

    White, Matthew D; Bosio, Catharine M; Duplantis, Barry N; Nano, Francis E

    2011-09-01

    Many of the live human and animal vaccines that are currently in use are attenuated by virtue of their temperature-sensitive (TS) replication. These vaccines are able to function because they can take advantage of sites in mammalian bodies that are cooler than the core temperature, where TS vaccines fail to replicate. In this article, we discuss the distribution of temperature in the human body, and relate how the temperature differential can be exploited for designing and using TS vaccines. We also examine how one of the coolest organs of the body, the skin, contains antigen-processing cells that can be targeted to provoke the desired immune response from a TS vaccine. We describe traditional approaches to making TS vaccines, and highlight new information and technologies that are being used to create a new generation of engineered TS vaccines. We pay particular attention to the recently described technology of substituting essential genes from Arctic bacteria for their homologues in mammalian pathogens as a way of creating TS vaccines.

  3. On rate-dependent polycrystal deformation: the temperature sensitivity of cold dwell fatigue.

    Science.gov (United States)

    Zhang, Zhen; Cuddihy, M A; Dunne, F P E

    2015-09-08

    A temperature and rate-dependent crystal plasticity framework has been used to examine the temperature sensitivity of stress relaxation, creep and load shedding in model Ti-6Al polycrystal behaviour under dwell fatigue conditions. A temperature close to 120°C is found to lead to the strongest stress redistribution and load shedding, resulting from the coupling between crystallographic slip rate and slip system dislocation hardening. For temperatures in excess of about 230°C, grain-level load shedding from soft to hard grains diminishes because of the more rapid stress relaxation, leading ultimately to the diminution of the load shedding and hence, it is argued, the elimination of the dwell debit. Under conditions of cyclic stress dwell, at temperatures between 20°C and 230°C for which load shedding occurs, the rate-dependent accumulation of local slip by ratcheting is shown to lead to the progressive cycle-by-cycle redistribution of stress from soft to hard grains. This phenomenon is termed cyclic load shedding since it also depends on the material's creep response, but develops over and above the well-known dwell load shedding, thus providing an additional rationale for the incubation of facet nucleation.

  4. The Neurospora crassa colonial temperature-sensitive 3 (cot-3) gene encodes protein elongation factor 2.

    Science.gov (United States)

    Propheta, O; Vierula, J; Toporowski, P; Gorovits, R; Yarden, O

    2001-02-01

    At elevated temperatures, the Neurospora crassa mutant colonial, temperature-sensitive 3 (cot-3) forms compact, highly branched colonies. Growth of the cot-3 strain under these conditions also results in the loss of the lower molecular weight (LMW) isoform of the Ser/Thr protein kinase encoded by the unlinked cot-1 gene, whose function is also involved in hyphal elongation. The unique cot-3 gene has been cloned by complementation and shown to encode translation elongation factor 2 (EF-2). As expected for a gene with a general role in protein synthesis, cot-3 mRNA is abundantly expressed throughout all asexual phases of the N. crassa life cycle. The molecular basis of the cot-3 mutation was determined to be an ATT to AAT transversion, which causes an Ile to Asn substitution at residue 278. Treatment with fusidic acid (a specific inhibitor of EF-2) inhibits hyphal elongation and induces hyperbranching in a manner which mimics the cot-3 phenotype, and also leads to a decrease in the abundance of the LMW isoform of COT1. This supports our conclusion that the mutation in cot-3 which results in abnormal hyphal elongation/branching impairs EF-2 function and confirms that the abundance of a LMW isoform of COT1 kinase is dependent on the function of this general translation factor.

  5. A streptomycin-resistant Escherichia coli mutant with ribosomes temperature-sensitive in the suppression of a nonsense codon.

    Science.gov (United States)

    Zeevi, M; Daniel, V; Engelberg-Kulka, H

    1979-02-26

    Cell free extracts from a streptomycin-resistant E. coli mutant which is also temperature-sensitive for Q beta phage were studied for suppression of a nonsense mutation at various temperatures. The streptomycin-resistant ribosomes of the mutant were found to be temperature-sensitive in suppression of an amber mutation in f2 phage coat protein while retaining the ability to synthesize proteins at an elevated temperature (42 degrees C). The restriction of amber suppression at 42 degrees C is assumed to be related to an alteration in ribosomal protein S12 of the streptomycin-resistant mutant which also causes a change in its electrophoretic mobility.

  6. Strain and temperature sensitivities of an elliptical hollow-core photonic bandgap fiber based on Sagnac interferometer.

    Science.gov (United States)

    Kim, Gilhwan; Cho, Taiyong; Hwang, Kyujin; Lee, Kwanil; Lee, Kyung S; Han, Young-Geun; Lee, Sang Bae

    2009-02-16

    We fabricated an elliptical hollow-core photonic bandgap fiber (EC-PBGF) by controlling lateral tension in the hollow core region during the fiber drawing process. The absolute value of group modal birefringence becomes relatively high near the bandgap boundaries. We also experimentally measured the strain and temperature sensitivities of the fabricated EC-PBGF-based Sagnac loop interferometer. The strain and temperature sensitivities were very much dependent upon the wavelength. Moreover this PBGF-based interferometer can be a good sensor of physical parameters such as strain and temperature.

  7. A method for the determination of bacterial spore DNA content based on isotopic labelling, spore germination and diphenylamine assay; ploidy of spores of several Bacillus species

    International Nuclear Information System (INIS)

    Hauser, P.M.; Karamata, D.

    1992-01-01

    A reliable method for measuring the spore DNA content, based on radioactive DNA labelling, spore germination in absence of DNA replication and diphenylamine assay, was developed. The accuracy of the method, within 10 - 15%, is adequate for determining the number of chromosomes per spore, provided that the genome size is known. B subtilis spores were shown to be invariably monogenomic, while those of larger bacilli Bacillus megaterium, Bacillus cereus and Bacillus thuringiensis, often, if not invariably, contain two genomes. Attempts to modify the spore DNA content of B subtilis by altering the richness of the sporulation medium, the sporulation conditions (liquid or solid medium), or by mutation, were apparently unsuccessful. An increase of spore size with medium richness, not accompanied by an increase in DNA content, was observed. The implication of the apparently species-specific spore ploidy and the influence of the sporulation conditions on spore size and shape are discussed

  8. Bacterial spores in food: how phenotypic variability complicates prediction of spore properties and bacterial behavior

    NARCIS (Netherlands)

    Eijlander, R.T.; Abee, T.; Kuipers, O.P.

    2011-01-01

    Bacillus spores are a known cause of food spoilage and their increased resistance poses a major challenge in efficient elimination. Recent studies on bacterial cultures at the single cell level have revealed how minor differences in essential spore properties, such as core water content or germinant

  9. Bacterial spores in food : how phenotypic variability complicates prediction of spore properties and bacterial behavior

    NARCIS (Netherlands)

    Eijlander, Robyn T.; Abee, Tjakko; Kuipers, Oscar P.

    Bacillus spores are a known cause of food spoilage and their increased resistance poses a major challenge in efficient elimination. Recent studies on bacterial cultures at the single cell level have revealed how minor differences in essential spore properties, such as core water content or germinant

  10. Bacillus cereus spore damage recovery and diversity in spore germination and carbohydrate utilisation

    NARCIS (Netherlands)

    Warda, Alicja K.

    2016-01-01

    Bacterial spores are extremely robust survival vehicles that are highly resistant towards environmental stress conditions including heat, UV radiation and other stresses commonly applied during food production and preservation. Spores, including those of the toxin-producing food-borne human pathogen

  11. Bacillus cereus spore damage recovery and diversity in spore germination and carbohydrate utilisation

    NARCIS (Netherlands)

    Warda, Alicja K.

    2016-01-01

    Bacterial spores are extremely robust survival vehicles that are highly resistant towards environmental stress conditions including heat, UV radiation and other stresses commonly applied during food production and preservation. Spores, including those of the toxin-producing food-borne human

  12. Temperature-sensitive PSII: a novel approach for sustained photosynthetic hydrogen production.

    Science.gov (United States)

    Bayro-Kaiser, Vinzenz; Nelson, Nathan

    2016-12-01

    The need for energy and the associated burden are ever growing. It is crucial to develop new technologies for generating clean and efficient energy for society to avoid upcoming energetic and environmental crises. Sunlight is the most abundant source of energy on the planet. Consequently, it has captured our interest. Certain microalgae possess the ability to capture solar energy and transfer it to the energy carrier, H 2 . H 2 is a valuable fuel, because its combustion produces only one by-product: water. However, the establishment of an efficient biophotolytic H 2 production system is hindered by three main obstacles: (1) the hydrogen-evolving enzyme, [FeFe]-hydrogenase, is highly sensitive to oxygen; (2) energy conversion efficiencies are not economically viable; and (3) hydrogen-producing organisms are sensitive to stressful conditions in large-scale production systems. This study aimed to circumvent the oxygen sensitivity of this process with a cyclic hydrogen production system. This approach required a mutant that responded to high temperatures by reducing oxygen evolution. To that end, we randomly mutagenized the green microalgae, Chlamydomonas reinhardtii, to generate mutants that exhibited temperature-sensitive photoautotrophic growth. The selected mutants were further characterized by their ability to evolve oxygen and hydrogen at 25 and 37 °C. We identified four candidate mutants for this project. We characterized these mutants with PSII fluorescence, P700 absorbance, and immunoblotting analyses. Finally, we demonstrated that these mutants could function in a prototype hydrogen-producing bioreactor. These mutant microalgae represent a novel approach for sustained hydrogen production.

  13. Effects of Soil Moisture on the Temperature Sensitivity of Soil Heterotrophic Respiration: A Laboratory Incubation Study

    Science.gov (United States)

    Zhou, Weiping; Hui, Dafeng; Shen, Weijun

    2014-01-01

    The temperature sensitivity (Q10) of soil heterotrophic respiration (Rh) is an important ecological model parameter and may vary with temperature and moisture. While Q10 generally decreases with increasing temperature, the moisture effects on Q10 have been controversial. To address this, we conducted a 90-day laboratory incubation experiment using a subtropical forest soil with a full factorial combination of five moisture levels (20%, 40%, 60%, 80%, and 100% water holding capacity - WHC) and five temperature levels (10, 17, 24, 31, and 38°C). Under each moisture treatment, Rh was measured several times for each temperature treatment to derive Q10 based on the exponential relationships between Rh and temperature. Microbial biomass carbon (MBC), microbial community structure and soil nutrients were also measured several times to detect their potential contributions to the moisture-induced Q10 variation. We found that Q10 was significantly lower at lower moisture levels (60%, 40% and 20% WHC) than at higher moisture level (80% WHC) during the early stage of the incubation, but became significantly higher at 20%WHC than at 60% WHC and not significantly different from the other three moisture levels during the late stage of incubation. In contrast, soil Rh had the highest value at 60% WHC and the lowest at 20% WHC throughout the whole incubation period. Variations of Q10 were significantly associated with MBC during the early stages of incubation, but with the fungi-to-bacteria ratio during the later stages, suggesting that changes in microbial biomass and community structure are related to the moisture-induced Q10 changes. This study implies that global warming’s impacts on soil CO2 emission may depend upon soil moisture conditions. With the same temperature rise, wetter soils may emit more CO2 into the atmosphere via heterotrophic respiration. PMID:24647610

  14. What is the Right Temperature Sensitivity for Foraminiferal Mg/ca Paleothermometry in Ancient Oceans?

    Science.gov (United States)

    Eggins, S.; Holland, K.; Hoenisch, B.; Spero, H. J.; Allen, K. A.

    2013-12-01

    Mg/Ca seawater thermometry has become a cornerstone of modern paleoceanography. Laboratory experiments, seafloor core-top samples, plankton trap and tow collected materials all indicate consistent temperature sensitivity (9-10% increase in Mg/Ca per °C) for a full range of modern planktic foraminifer species. While these results demonstrate the overall robustness of Mg/Ca paleothermometry for the modern ocean, it is an empirical tool for which there is limited understanding of its bio-physio-chemical basis and its applicability to ancient oceans. We have undertaken experimental cultures of Orbulina universa, Globigerinoides sacculifer and Globigerinoides ruber (pink) across a range of seawater compositions (temperature, carbonate chemistry and Mg/Casw) that encompass modern and ancient Paleogene and Cretaceous ocean compositions (Mg/Casw 0.25x to 2x modern and pCO2 = 200 to 1500 ppmv). Our results reveal that the sensitivity of the Mg/Ca-thermometer for planktic foraminifers reduces significantly with Mg/Casw, rather than remaining constant as has been widely assumed or, increasing at lower Mg/Casw as proposed recently by Evans and Müller (2012). These results indicate that the modern sensitivity of 9-10% increase in Mg/Ca per °C cannot yet be applied to obtain reliable relative temperature change estimates to ancient oceans. These results further suggest that variations in foraminiferal Mg/Ca compositions in ancient oceans with lower Mg/Casw may correspond to larger temperature variations than in the modern ocean. Evans D. and Müller W., Paleoceanography, vol. 27, PA4205, doi:10.1029/2012PA002315, 2012

  15. Thermo-optical characterization of fluorescent rhodamine B based temperature-sensitive nanosensors using a CMOS MEMS micro-hotplate.

    Science.gov (United States)

    Chauhan, Veeren M; Hopper, Richard H; Ali, Syed Z; King, Emma M; Udrea, Florin; Oxley, Chris H; Aylott, Jonathan W

    2014-03-01

    A custom designed microelectromechanical systems (MEMS) micro-hotplate, capable of operating at high temperatures (up to 700 °C), was used to thermo-optically characterize fluorescent temperature-sensitive nanosensors. The nanosensors, 550 nm in diameter, are composed of temperature-sensitive rhodamine B (RhB) fluorophore which was conjugated to an inert silica sol-gel matrix. Temperature-sensitive nanosensors were dispersed and dried across the surface of the MEMS micro-hotplate, which was mounted in the slide holder of a fluorescence confocal microscope. Through electrical control of the MEMS micro-hotplate, temperature induced changes in fluorescence intensity of the nanosensors was measured over a wide temperature range. The fluorescence response of all nanosensors dispersed across the surface of the MEMS device was found to decrease in an exponential manner by 94%, when the temperature was increased from 25 °C to 145 °C. The fluorescence response of all dispersed nanosensors across the whole surface of the MEMS device and individual nanosensors, using line profile analysis, were not statistically different ( p  MEMS device used for this study could prove to be a reliable, low cost, low power and high temperature micro-hotplate for the thermo-optical characterisation of sub-micron sized particles. The temperature-sensitive nanosensors could find potential application in the measurement of temperature in biological and micro-electrical systems.

  16. Dothistroma septosporum: spore production and weather conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dvorak, M.; Drapela, K.; Kankovsky, L.

    2012-11-01

    Dartmouth's septosporum, the causal agent of Dothistroma needle blight is a widespread fungus which infects more than 80 species of coniferous trees through the entire world. Spreading of the infection is strongly affected by climatic factors of each locality where it is recorded. We attempt to describe the concrete limiting climatic factors necessary for the releasing of conidia of D. septosporum and to find out the timing of its spore production within the year. For this purpose we used an automatic volumetric spore trap and an automatic meteorological station. We found that a minimum daily average temperature of 10 degree centigrade was necessary for any spore production, as well as a long period of high air humidity. The values obtained in the present study were a little bit higher than those previously published, which may arise questions about a possible changing trend of the behaviour in the development of the Dothistroma needle blight causal agent. We used autoregressive integrated moving average (ARIMA) models to predict the spore counts on the base of previous values of spore counts and dew point. For a locality from Hackerovka, the best ARIMA model was 1,0,0; and for a locality from Lanzhot, the best was 3,1,0. (Author) 19 refs.

  17. Role of DNA repair in Bacillus subtilis spore resistance.

    OpenAIRE

    Setlow, B; Setlow, P

    1996-01-01

    Wet-heat or hydrogen peroxide treatment of wild-type Bacillus subtilis spores did not result in induction of lacZ fusions to three DNA repair-related genes (dinR, recA, and uvrC) during spore outgrowth. However, these genes were induced during outgrowth of wild-type spores treated with dry heat or UV. Wet-heat, desiccation, dry-heat, or UV treatment of spores lacking major DNA-binding proteins (termed alpha-beta- spores) also resulted in induction of the three DNA repair genes during spore ou...

  18. Isolation and Characterization of Cryptococcus neoformans Spores Reveal a Critical Role for Capsule Biosynthesis Genes in Spore Biogenesis▿

    Science.gov (United States)

    Botts, Michael R.; Giles, Steven S.; Gates, Marcellene A.; Kozel, Thomas R.; Hull, Christina M.

    2009-01-01

    Spores are essential particles for the survival of many organisms, both prokaryotic and eukaryotic. Among the eukaryotes, fungi have developed spores with superior resistance and dispersal properties. For the human fungal pathogens, however, relatively little is known about the role that spores play in dispersal and infection. Here we present the purification and characterization of spores from the environmental fungus Cryptococcus neoformans. For the first time, we purified spores to homogeneity and assessed their morphological, stress resistance, and surface properties. We found that spores are morphologically distinct from yeast cells and are covered with a thick spore coat. Spores are also more resistant to environmental stresses than yeast cells and display a spore-specific configuration of polysaccharides on their surfaces. Surprisingly, we found that the surface of the spore reacts with antibodies to the polysaccharide glucuronoxylomannan, the most abundant component of the polysaccharide capsule required for C. neoformans virulence. We explored the role of capsule polysaccharide in spore development by assessing spore formation in a series of acapsular strains and determined that capsule biosynthesis genes are required for proper sexual development and normal spore formation. Our findings suggest that C. neoformans spores may have an adapted cell surface that facilitates persistence in harsh environments and ultimately allows them to infect mammalian hosts. PMID:19181873

  19. Differences in the Temperature Sensitivity of Soil Organic Carbon Decomposition in a Semi-Arid Ecosystem across an Elevational Gradient

    Science.gov (United States)

    Delvinne, H.; Flores, A. N.; Benner, S. G.; Feris, K. P.; De Graaff, M. A.

    2015-12-01

    Semi-arid ecosystems are a significant component of the global carbon (C) cycle as they store approximately 20% of global soil C. Yet, projected increases in mean annual temperatures might alter the amount of soil organic C (SOC) currently stored in these ecosystems. Uncertainties about the temperature sensitivity of SOC decomposition have hindered accurate predictions of C cycle feedbacks to climate change. This study aims to elucidate how the temperature sensitivity of SOC decomposition varies along an elevational (1000m) and climatic (i.e. mean annual temperature and precipitation) gradient. The study sites are located at Reynolds Creek Critical Zone Observatory in Owyhee Mountains of Idaho, USA. We conducted stratified random sampling of soil up to 0-5cm across sagebrush canopy and inter-canopy areas at four elevations. We hypothesized decomposition of SOC pools at lower elevations to have greater temperature sensitivity (more CO2 respired per unit C) compared to upper due to the quality of C that is inherently more temperature sensitive. To assess the temperature sensitivity of SOC decomposition, we used aerobic laboratory incubations (n=40) across a temperature gradient ((15, 20, 25, 30) oC) at constant soil moisture (60% water holding capacity) for 120 days and measured CO2 respired. Cumulative CO2 respired increased with increasing incubation temperature. Cumulative CO2 respired also increased with elevation as upper elevations support greater amounts of C. However, when normalized by SOC, we found that the temperature response of CO2 respiration was greater in soils derived from lower than higher elevations (pelevated temperatures differs strongly across the landscape in semi-arid ecosystems.

  20. Handling technique of spore-forming bacteria in radiation sterilization. 2. Determination of numbers and radiation resistance of spores

    International Nuclear Information System (INIS)

    Koshikawa, Tomihiko

    1994-01-01

    Stepwise ten-fold dilution of bacterial solution is required in the determination of bacterial spores. For this, the selection of diluted solution is important according to the purpose of experiment. First, the preparation of suspension of bacterial spores and selection of diluted solution are presented. Then, a method for determining the number of bacterial spores in materials is outlined in terms of dilution methods of bacterial solution (shaking and homogenization) and application method of diluted solution to the plating medium. Finally, a method for determining radiation resistance of spore-forming bacteria is explained according to the measurement conditions (suspension of bacterial spores and filters applied with bacterial spores). (N.K.)

  1. Handling technique of spore-forming bacteria in radiation sterilization. 2. Determination of numbers and radiation resistance of spores

    Energy Technology Data Exchange (ETDEWEB)

    Koshikawa, Tomihiko [Japan Radioisotope Association, Shiga (Japan). Koka Laboratory

    1994-12-01

    Stepwise ten-fold dilution of bacterial solution is required in the determination of bacterial spores. For this, the selection of diluted solution is important according to the purpose of experiment. First, the preparation of suspension of bacterial spores and selection of diluted solution are presented. Then, a method for determining the number of bacterial spores in materials is outlined in terms of dilution methods of bacterial solution (shaking and homogenization) and application method of diluted solution to the plating medium. Finally, a method for determining radiation resistance of spore-forming bacteria is explained according to the measurement conditions (suspension of bacterial spores and filters applied with bacterial spores). (N.K.).

  2. Rate of warming affects temperature sensitivity of anaerobic peat decomposition and greenhouse gas production.

    Science.gov (United States)

    Sihi, Debjani; Inglett, Patrick W; Gerber, Stefan; Inglett, Kanika S

    2018-01-01

    Temperature sensitivity of anaerobic carbon mineralization in wetlands remains poorly represented in most climate models and is especially unconstrained for warmer subtropical and tropical systems which account for a large proportion of global methane emissions. Several studies of experimental warming have documented thermal acclimation of soil respiration involving adjustments in microbial physiology or carbon use efficiency (CUE), with an initial decline in CUE with warming followed by a partial recovery in CUE at a later stage. The variable CUE implies that the rate of warming may impact microbial acclimation and the rate of carbon-dioxide (CO 2 ) and methane (CH 4 ) production. Here, we assessed the effects of warming rate on the decomposition of subtropical peats, by applying either a large single-step (10°C within a day) or a slow ramping (0.1°C/day for 100 days) temperature increase. The extent of thermal acclimation was tested by monitoring CO 2 and CH 4 production, CUE, and microbial biomass. Total gaseous C loss, CUE, and MBC were greater in the slow (ramp) warming treatment. However, greater values of CH 4 -C:CO 2 -C ratios lead to a greater global warming potential in the fast (step) warming treatment. The effect of gradual warming on decomposition was more pronounced in recalcitrant and nutrient-limited soils. Stable carbon isotopes of CH 4 and CO 2 further indicated the possibility of different carbon processing pathways under the contrasting warming rates. Different responses in fast vs. slow warming treatment combined with different endpoints may indicate alternate pathways with long-term consequences. Incorporations of experimental results into organic matter decomposition models suggest that parameter uncertainties in CUE and CH 4 -C:CO 2 -C ratios have a larger impact on long-term soil organic carbon and global warming potential than uncertainty in model structure, and shows that particular rates of warming are central to understand the

  3. Comparison of conventional chemotherapy, stealth liposomes and temperature-sensitive liposomes in a mathematical model.

    Science.gov (United States)

    Gasselhuber, Astrid; Dreher, Matthew R; Rattay, Frank; Wood, Bradford J; Haemmerich, Dieter

    2012-01-01

    Various liposomal drug carriers have been developed to overcome short plasma half-life and toxicity related side effects of chemotherapeutic agents. We developed a mathematical model to compare different liposome formulations of doxorubicin (DOX): conventional chemotherapy (Free-DOX), Stealth liposomes (Stealth-DOX), temperature sensitive liposomes (TSL) with intra-vascular triggered release (TSL-i), and TSL with extra-vascular triggered release (TSL-e). All formulations were administered as bolus at a dose of 9 mg/kg. For TSL, we assumed locally triggered release due to hyperthermia for 30 min. Drug concentrations were determined in systemic plasma, aggregate body tissue, cardiac tissue, tumor plasma, tumor interstitial space, and tumor cells. All compartments were assumed perfectly mixed, and represented by ordinary differential equations. Contribution of liposomal extravasation was negligible in the case of TSL-i, but was the major delivery mechanism for Stealth-DOX and for TSL-e. The dominant delivery mechanism for TSL-i was release within the tumor plasma compartment with subsequent tissue- and cell uptake of released DOX. Maximum intracellular tumor drug concentrations for Free-DOX, Stealth-DOX, TSL-i, and TSL-e were 3.4, 0.4, 100.6, and 15.9 µg/g, respectively. TSL-i and TSL-e allowed for high local tumor drug concentrations with reduced systemic exposure compared to Free-DOX. While Stealth-DOX resulted in high tumor tissue concentrations compared to Free-DOX, only a small fraction was bioavailable, resulting in little cellular uptake. Consistent with clinical data, Stealth-DOX resulted in similar tumor intracellular concentrations as Free-DOX, but with reduced systemic exposure. Optimal release time constants for maximum cellular uptake for Stealth-DOX, TSL-e, and TSL-i were 45 min, 11 min, and constants were shorter for MDR cells, with ∼4 min for Stealth-DOX and for TSL-e. Tissue concentrations correlated well quantitatively with a prior in-vivo study

  4. Comparison of conventional chemotherapy, stealth liposomes and temperature-sensitive liposomes in a mathematical model.

    Directory of Open Access Journals (Sweden)

    Astrid Gasselhuber

    Full Text Available Various liposomal drug carriers have been developed to overcome short plasma half-life and toxicity related side effects of chemotherapeutic agents. We developed a mathematical model to compare different liposome formulations of doxorubicin (DOX: conventional chemotherapy (Free-DOX, Stealth liposomes (Stealth-DOX, temperature sensitive liposomes (TSL with intra-vascular triggered release (TSL-i, and TSL with extra-vascular triggered release (TSL-e. All formulations were administered as bolus at a dose of 9 mg/kg. For TSL, we assumed locally triggered release due to hyperthermia for 30 min. Drug concentrations were determined in systemic plasma, aggregate body tissue, cardiac tissue, tumor plasma, tumor interstitial space, and tumor cells. All compartments were assumed perfectly mixed, and represented by ordinary differential equations. Contribution of liposomal extravasation was negligible in the case of TSL-i, but was the major delivery mechanism for Stealth-DOX and for TSL-e. The dominant delivery mechanism for TSL-i was release within the tumor plasma compartment with subsequent tissue- and cell uptake of released DOX. Maximum intracellular tumor drug concentrations for Free-DOX, Stealth-DOX, TSL-i, and TSL-e were 3.4, 0.4, 100.6, and 15.9 µg/g, respectively. TSL-i and TSL-e allowed for high local tumor drug concentrations with reduced systemic exposure compared to Free-DOX. While Stealth-DOX resulted in high tumor tissue concentrations compared to Free-DOX, only a small fraction was bioavailable, resulting in little cellular uptake. Consistent with clinical data, Stealth-DOX resulted in similar tumor intracellular concentrations as Free-DOX, but with reduced systemic exposure. Optimal release time constants for maximum cellular uptake for Stealth-DOX, TSL-e, and TSL-i were 45 min, 11 min, and <3 s, respectively. Optimal release time constants were shorter for MDR cells, with ∼4 min for Stealth-DOX and for TSL-e. Tissue concentrations

  5. Increase of ozone concentrations, its temperature sensitivity and the precursor factor in South China

    Directory of Open Access Journals (Sweden)

    Y. C. Lee

    2014-08-01

    Full Text Available Concerns have been raised about the possible connections between the local and regional photochemical problem and global warming. The current study assesses the trend of ozone in Hong Kong and the Pearl River Delta (PRD in South China and investigates the interannual changes of sensitivity of ozone to air temperature, as well as the trends in regional precursors. Results reveal, at the three monitoring sites from the mid-1990s to 2010, an increase in the mean ozone concentrations from 1.0 to 1.6 µg m−3 per year. The increase occurred in all seasons, with the highest rate in autumn. This is consistent with trends and temperature anomalies in the region. The increase in the sensitivity of ozone to temperature is clearly evident from the correlation between ozone (OMI [Ozone Monitoring Instrument] column amount and surface air temperature (from the Atmospheric Infrared Sounder displayed in the correlation maps for the PRD during the prominently high ozone period of July–September. It is observed to have increased from 2005 to 2010, the latter being the hottest year on record globally. To verify this temporal change in sensitivity, the ground-level trends of correlation coefficients/regression slopes are analysed. As expected, results reveal a statistically significant upward trend over a 14-year period (1997–2010. While the correlation revealed in the correlation maps is in agreement with the corresponding OMI ozone maps when juxtaposed, temperature sensitivity of surface ozone also shows an association with ozone concentration, with R=0.5. These characteristics of ozone sensitivity are believed to have adverse implications for the region. As shown by ground measurements and/or satellite analyses, the decrease in nitrogen oxides (NO2 and NOx in Hong Kong is not statistically significant while NO2 of the PRD has only very slightly changed. However, carbon dioxide has remarkably declined in the whole region. While these observations concerning

  6. High-Resolution Spore Coat Architecture and Assembly of Bacillus Spores

    Energy Technology Data Exchange (ETDEWEB)

    Malkin, A J; Elhadj, S; Plomp, M

    2011-03-14

    Elucidating the molecular architecture of bacterial and cellular surfaces and its structural dynamics is essential to understanding mechanisms of pathogenesis, immune response, physicochemical interactions, environmental resistance, and provide the means for identifying spore formulation and processing attributes. I will discuss the application of in vitro atomic force microscopy (AFM) for studies of high-resolution coat architecture and assembly of several Bacillus spore species. We have demonstrated that bacterial spore coat structures are phylogenetically and growth medium determined. We have proposed that strikingly different species-dependent coat structures of bacterial spore species are a consequence of sporulation media-dependent nucleation and crystallization mechanisms that regulate the assembly of the outer spore coat. Spore coat layers were found to exhibit screw dislocations and two-dimensional nuclei typically observed on inorganic and macromolecular crystals. This presents the first case of non-mineral crystal growth patterns being revealed for a biological organism, which provides an unexpected example of nature exploiting fundamental materials science mechanisms for the morphogenetic control of biological ultrastructures. We have discovered and validated, distinctive formulation-specific high-resolution structural spore coat and dimensional signatures of B. anthracis spores (Sterne strain) grown in different formulation condition. We further demonstrated that measurement of the dimensional characteristics of B. anthracis spores provides formulation classification and sample matching with high sensitivity and specificity. I will present data on the development of an AFM-based immunolabeling technique for the proteomic mapping of macromolecular structures on the B. anthracis surfaces. These studies demonstrate that AFM can probe microbial surface architecture, environmental dynamics and the life cycle of bacterial and cellular systems at near

  7. Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA2mob Operon in Foodborne Strains of Bacillus subtilis.

    Science.gov (United States)

    Krawczyk, Antonina O; de Jong, Anne; Omony, Jimmy; Holsappel, Siger; Wells-Bennik, Marjon H J; Kuipers, Oscar P; Eijlander, Robyn T

    2017-04-01

    Spore heat resistance, germination, and outgrowth are problematic bacterial properties compromising food safety and quality. Large interstrain variation in these properties makes prediction and control of spore behavior challenging. High-level heat resistance and slow germination of spores of some natural Bacillus subtilis isolates, encountered in foods, have been attributed to the occurrence of the spoVA 2mob operon carried on the Tn 1546 transposon. In this study, we further investigate the correlation between the presence of this operon in high-level-heat-resistant spores and their germination efficiencies before and after exposure to various sublethal heat treatments (heat activation, or HA), which are known to significantly improve spore responses to nutrient germinants. We show that high-level-heat-resistant spores harboring spoVA 2mob required higher HA temperatures for efficient germination than spores lacking spoVA 2mob The optimal spore HA requirements additionally depended on the nutrients used to trigger germination, l-alanine (l-Ala), or a mixture of l-asparagine, d-glucose, d-fructose, and K + (AGFK). The distinct HA requirements of these two spore germination pathways are likely related to differences in properties of specific germinant receptors. Moreover, spores that germinated inefficiently in AGFK contained specific changes in sequences of the GerB and GerK germinant receptors, which are involved in this germination response. In contrast, no relation was found between transcription levels of main germination genes and spore germination phenotypes. The findings presented in this study have great implications for practices in the food industry, where heat treatments are commonly used to inactivate pathogenic and spoilage microbes, including bacterial spore formers. IMPORTANCE This study describes a strong variation in spore germination capacities and requirements for a heat activation treatment, i.e., an exposure to sublethal heat that increases

  8. Dendritic Cells Endocytose Bacillus Anthracis Spores: Implications for Anthrax Pathogenesis

    National Research Council Canada - National Science Library

    Brittingham, Katherine C; Ruthel, Gordon; Panchal, Rekha G; Fuller, Claudette L; Ribot, Wilson J

    2005-01-01

    Phagocytosis of inhaled Bacillus anthracis spores and subsequent trafficking to lymph nodes are decisive events in the progression of inhaled anthrax because they initiate germination and dissemination of spores...

  9. Temperature sensitivity of extracellular enzyme kinetics in subtropical wetland soils under different nutrient and water level conditions

    Science.gov (United States)

    Goswami, S.; Inglett, K.; Inglett, P.

    2012-12-01

    Microbial extracellular enzymes play an important role in the initial steps of soil organic matter decomposition and are involved in regulating nutrient cycle processes. Moreover, with the recent concern of climate change, microbial extracellular enzymes may affect the functioning (C losses, C sequestration, greenhouse gas emissions, vegetation changes) of different ecosystems. Hence, it is imperative to understand the biogeochemical processes that may be climate change sensitive. Here, we have measured the Michaelis Menten Kinetics [maximal rate of velocity (Vmax) and half-saturation constant (Km)] of 6 enzymes involved in soil organic matter decomposition (phosphatase, phosphodiesterase, β-D-glucosidase, cellobiohydrolase, leucine aminopeptidase, N-Acetyl-β-D glucosaminidase) in different nutrient(P) concentration both aerobically and anaerobically in Everglade water conservation area 2A (F1, F4-slough and U3-slough). Temperature sensitivity of different enzymes is assessed within soil of different P concentrations. We hypothesized that the temperature sensitivity of the enzyme changes with the biogeochemical conditions including water level and nutrient condition. Furthermore, we have tested specific hypothesis that higher P concentration will initiate more C demand for microbes leading to higher Vmax value for carbon processing enzymes in high P site. We found temperature sensitivity of all enzymes for Vmax and Km under both aerobic and anaerobic condition ranges from 0.6 to 3.2 for Vmax and 0.5 to 2.5 for Km. Q10 values of Km for glucosidase indicate more temperature sensitivity under anaerobic condition. Under aerobic condition higher temperature showed significant effect on Vmax for bisphosphatase between high P and low P site. Decreasing P concentration from F1 site to U3-S site had showed significant effect in all temperature on carbon processing enzyme. This suggests that in high P site, microbes will use more carbon-processing enzyme to get more carbon

  10. Testing the Metabolic Theory of Ecology with marine bacteria: Different temperature sensitivity of major phylogenetic groups during the spring phytoplankton bloom

    KAUST Repository

    Arandia-Gorostidi, Nestor

    2017-08-24

    Although temperature is a key driver of bacterioplankton metabolism, the effect of ocean warming on different bacterial phylogenetic groups remains unclear. Here, we conducted monthly short-term incubations with natural coastal bacterial communities over an annual cycle to test the effect of experimental temperature on the growth rates and carrying capacities of four phylogenetic groups: SAR11, Rhodobacteraceae, Gammaproteobacteria and Bacteroidetes. SAR11 was the most abundant group year-round as analysed by CARD-FISH, with maximum abundances in summer, while the other taxa peaked in spring. All groups, including SAR11, showed high temperature-sensitivity of growth rates and/or carrying capacities in spring, under phytoplankton bloom or post-bloom conditions. In that season, Rhodobacteraceae showed the strongest temperature response in growth rates, estimated here as activation energy (E, 1.43 eV), suggesting an advantage to outcompete other groups under warmer conditions. In summer E values were in general lower than 0.65 eV, the value predicted by the Metabolic Theory of Ecology (MTE). Contrary to MTE predictions, carrying capacity tended to increase with warming for all bacterial groups. Our analysis confirms that resource availability is key when addressing the temperature response of heterotrophic bacterioplankton. We further show that even under nutrient-sufficient conditions, warming differentially affected distinct bacterioplankton taxa. This article is protected by copyright. All rights reserved.

  11. Fifth international fungus spore conference. [Abstracts]: Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Timberlake, W.E.

    1993-04-01

    This folio contains the proceedings of the Fifth International Fungal Spore Conference held August 17-21, 1991 at the Unicoi State Park at Helen, Georgia. The volume contains abstracts of each oral presentation as well as a collection of abstracts describing the poster sessions. Presentations were organized around the themes (1) Induction of Sporulation, (2) Nuclear Division, (3) Spore Formation, (4) Spore Release and Dispersal, and (4) Spore Germination.

  12. Measurement of Metabolic Activity in Dormant Spores of Bacillus Species

    Science.gov (United States)

    2015-01-14

    SECURITY CLASSIFICATION OF: Spores of Bacillus megaterium and Bacillus subtilis were harvested shortly after release from sporangia, incubated under...Dec-2014 Approved for Public Release; Distribution Unlimited Final Report: Measurement of Metabolic Activity in Dormant Spores of Bacillus Species...Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 spores, Bacillus , spore dormancy, 3-phosphoglycerate REPORT DOCUMENTATION PAGE 11

  13. Geraniol biotransformation-pathway in spores of Penicillium digitatum

    NARCIS (Netherlands)

    Wolken, W.A.M.; Werf, M.J. van der

    2001-01-01

    Spores of Penicillium digitatum ATCC 201167 transform geraniol, nerol, citral, and geranic acid into methylheptenone. Spore extracts of P. digitatum convert geraniol and nerol NAD+-dependently into citral. Spore extract also converts citral NAD+-dependently into geranic acid. Furthermore, a novel

  14. Expression and characterization of a novel spore wall protein from ...

    African Journals Online (AJOL)

    Microsporidia are obligate intracellular, eukaryotic, spore-forming parasites. The environmentally resistant spores, which harbor a rigid cell wall, are critical for their survival outside their host cells and host-to-host transmission. The spore wall comprises two major layers: the exospore and the endospore. In Nosema ...

  15. Imaging bacterial spores by soft-x-ray microscopy

    International Nuclear Information System (INIS)

    Stead, A.D.; Ford, T.W.; Judge, J.

    1997-01-01

    Bacterial spores are able to survive dehydration, but neither the physiological nor structural basis of this have been fully elucidated. Furthermore, once hydrated, spores often require activation before they will germinate. Several treatments can be used to activate spores, but in the case of Bacillus subtlis the most effective is heat treatment. The physiological mechanism associated with activation is also not understood, but some workers suggest that the loss of calcium from the spores may be critical. However, just prior to germination, the spores change from being phase bright to phase dark when viewed by light microscopy. Imaging spores by soft x-ray microscopy is possible without fixation. Thus, in contrast to electron microscopy, it is possible to compare the structure of dehydrated and hydrated spores in a manner not possible previously. A further advantage is that it is possible to monitor individual spores by phase contrast light microscopy immediately prior to imaging with soft x-rays; whereas, with both electron microscopy and biochemical studies, it is a population of spores being studied without knowledge of the phase characteristics of individual spores. This study has therefore tried to compare dehydrated and hydrated spores and to determine if there is a mass loss from individual spores as they pass the transition from being phase bright to phase dark

  16. Imaging bacterial spores by soft-x-ray microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stead, A.D.; Ford, T.W. [Univ. of London, Surrey (United Kingdom); Judge, J. [Unilever plc, Sharnbrook (United Kingdom)] [and others

    1997-04-01

    Bacterial spores are able to survive dehydration, but neither the physiological nor structural basis of this have been fully elucidated. Furthermore, once hydrated, spores often require activation before they will germinate. Several treatments can be used to activate spores, but in the case of Bacillus subtlis the most effective is heat treatment. The physiological mechanism associated with activation is also not understood, but some workers suggest that the loss of calcium from the spores may be critical. However, just prior to germination, the spores change from being phase bright to phase dark when viewed by light microscopy. Imaging spores by soft x-ray microscopy is possible without fixation. Thus, in contrast to electron microscopy, it is possible to compare the structure of dehydrated and hydrated spores in a manner not possible previously. A further advantage is that it is possible to monitor individual spores by phase contrast light microscopy immediately prior to imaging with soft x-rays; whereas, with both electron microscopy and biochemical studies, it is a population of spores being studied without knowledge of the phase characteristics of individual spores. This study has therefore tried to compare dehydrated and hydrated spores and to determine if there is a mass loss from individual spores as they pass the transition from being phase bright to phase dark.

  17. Spore Preparation Protocol for Enrichment of Clostridia from Murine Intestine.

    Science.gov (United States)

    Velazquez, Eric M; Rivera-Chávez, Fabian; Bäumler, Andreas J

    2017-05-20

    In recent years, many spore-forming commensal Clostridia found in the gut have been discovered to promote host physiology, immune development, and protection against infections. We provide a detailed protocol for rapid enrichment of spore-forming bacteria from murine intestine. Briefly, contents from the intestinal cecum are collected aerobically, diluted and finally treated with chloroform to enrich for Clostridia spores.

  18. Phospholipase Cδ regulates germination of Dictyostelium spores

    NARCIS (Netherlands)

    Dijken, Peter van; Haastert, Peter J.M. van

    2001-01-01

    Background: Many eukaryotes, including plants and fungi make spores that resist severe environmental stress. The micro-organism Dictyostelium contains a single phospholipase C gene (PLC); deletion of the gene has no effect on growth, cell movement and differentiation. In this report we show that PLC

  19. Detecting bacterial spores in soup manufacturing

    NARCIS (Netherlands)

    van Zuijlen, A.C.M.; Oomes, S.J.C.M.; Vos, P.; Brul, S.

    2009-01-01

    Spores from mesophilic aerobic sporeforming bacteria (Bacillus) are sometimes able to survive the thermal process of commercial sterile products and sporadically cause spoilage or food poisoning. Because of an increasing demand for more fresh products, ideally the processing temperatures should be

  20. Modeling to control spores in raw milk

    NARCIS (Netherlands)

    Vissers, M.

    2007-01-01

    A modeling approach was used to identify measures at the farm that reduce transmission of microorganisms to raw milk. Butyric acid bacteria (BAB) and Bacillus cereus were used as case-studies. Minimizing the concentration of BAB spores in raw milk is important to prevent late-blowing of Gouda-type

  1. On some white-spored Geoglossaceae

    NARCIS (Netherlands)

    Maas Geesteranus, R.A.

    1964-01-01

    Some genera of Geoglossaceae, characterized by colourless spores and positive iodine reaction of the ascus pore, are compared with respect to the structure of the stipe. Ochroglossum is reduced to the synonymy of Microglossum. Mitrula is regarded as a monotypic genus. The generic name Heyderia is

  2. Paleozoic in situ spores and pollen. Lycopsida

    Czech Academy of Sciences Publication Activity Database

    Bek, Jiří

    2017-01-01

    Roč. 296, 1/6 (2017), s. 1-111 ISSN 0375-0299 R&D Projects: GA ČR GAP210/12/2053 Institutional support: RVO:67985831 Keywords : in situ spores * reproductive organs * Lycopsida * Paleozoic Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Paleontology Impact factor: 1.333, year: 2016

  3. Behavioural thermoregulation in a temperature-sensitive coral reef fish, the five-lined cardinalfish (Cheilodipterus quinquelineatus)

    DEFF Research Database (Denmark)

    Nay, Tiffany J.; Johansen, Jacob L.; Habary, Adam

    2015-01-01

    provide a strategy to cope with changing conditions. A temperature-sensitive coral reef cardinalfish (Cheilodipterusquinquelineatus) was exposed to 28 °C (average at collection site) or 32 °C (predicted end-of-century) for 6 weeks. Tpref was determined using a shuttlebox system, which allowed fish...... than night-time movements. Understanding temperature-mediated movements is imperative for predicting how ocean warming will influence coral reef species and distribution patterns....

  4. Inhibiting Inosine Hydrolase and Alanine Racemase to Enhance the Germination of Bacillus anthracis Sterne Spores: Potential Spore Decontamination Strategies

    Science.gov (United States)

    2015-06-19

    2015): << Inhibiting inosine hydrolase and alanine racemase to enhance the germination of Bacillus anthracis Sterne spores: potential spore...display a currently valid OMB control number. 1. REPORT DATE 02 OCT 2015 2. REPORT TYPE N/A 3. DATES COVERED 4. TITLE AND SUBTITLE Inhibiting...inosine hydrolase and alanine racemase to enhance the germination of Bacillus anthracis Sterne spores potential spore decontamination strategies 5a

  5. Arabidopsis ZED1-related kinases mediate the temperature-sensitive intersection of immune response and growth homeostasis.

    Science.gov (United States)

    Wang, Zhicai; Cui, Dayong; Liu, Jing; Zhao, Jingbo; Liu, Cheng; Xin, Wei; Li, Yuan; Liu, Na; Ren, Dongtao; Tang, Dingzhong; Hu, Yuxin

    2017-07-01

    Activation of the immune response in plants antagonizes growth and development in the absence of pathogens, and such an autoimmune phenotype is often suppressed by the elevation of ambient temperature. However, molecular regulation of the ambient temperature-sensitive intersection of immune response and growth is largely elusive. A genetic screen identified an Arabidopsis mutant, zed1-D, by its high temperature-dependent growth retardation. A combination of molecular, cytological and genetic approaches was used to investigate the molecular basis behind the temperature-sensitive growth and immune response in zed1-D. A dominant mutation in HOPZ-ETI-DEFICIENT 1 (ZED1) is responsible for a high temperature-dependent autoimmunity and growth retardation in zed1-D. The autoimmune phenotype in zed1-D is dependent on the HOPZ-ACTIVATED RESISTANCE 1 (ZAR1). ZED1 and some ZED1-related kinases (ZRKs) are induced by elevated temperature and function cooperatively to suppress the immune response by modulating the transcription of SUPPRESSOR OF NPR1-1 CONSTITUTIVE 1 (SNC1) in the absence of pathogens. Our data reveal a previously unidentified role of ZRKs in the ambient temperature-sensitive immune response in the absence of pathogens, and thus reveals a possible molecular mechanism underlying the temperature-mediated intersection of immune response and growth in plants. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  6. Thermal Error Modeling Method with the Jamming of Temperature-Sensitive Points' Volatility on CNC Machine Tools

    Science.gov (United States)

    MIAO, Enming; LIU, Yi; XU, Jianguo; LIU, Hui

    2017-05-01

    Aiming at the deficiency of the robustness of thermal error compensation models of CNC machine tools, the mechanism of improving the models' robustness is studied by regarding the Leaderway-V450 machining center as the object. Through the analysis of actual spindle air cutting experimental data on Leaderway-V450 machine, it is found that the temperature-sensitive points used for modeling is volatility, and this volatility directly leads to large changes on the collinear degree among modeling independent variables. Thus, the forecasting accuracy of multivariate regression model is severely affected, and the forecasting robustness becomes poor too. To overcome this effect, a modeling method of establishing thermal error models by using single temperature variable under the jamming of temperature-sensitive points' volatility is put forward. According to the actual data of thermal error measured in different seasons, it is proved that the single temperature variable model can reduce the loss of forecasting accuracy resulted from the volatility of temperature-sensitive points, especially for the prediction of cross quarter data, the improvement of forecasting accuracy is about 5 μm or more. The purpose that improving the robustness of the thermal error models is realized, which can provide a reference for selecting the modeling independent variable in the application of thermal error compensation of CNC machine tools.

  7. Analysis of the temperature sensitivity of Japanese rubella vaccine strain TO-336.vac and its effect on immunogenicity in the guinea pig.

    Science.gov (United States)

    Okamoto, Kiyoko; Ami, Yasushi; Suzaki, Yuriko; Otsuki, Noriyuki; Sakata, Masafumi; Takeda, Makoto; Mori, Yoshio

    2016-04-01

    The marker of Japanese domestic rubella vaccines is their lack of immunogenicity in guinea pigs. This has long been thought to be related to the temperature sensitivity of the viruses, but supporting evidence has not been described. In this study, we generated infectious clones of TO-336.vac, a Japanese domestic vaccine, TO-336.GMK5, the parental virus of TO-336.vac, and their mutants, and determined the molecular bases of their temperature sensitivity and immunogenicity in guinea pigs. The results revealed that Ser(1159) in the non-structural protein-coding region was responsible for the temperature sensitivity of TO-336.vac dominantly, while the structural protein-coding region affected the temperature sensitivity subordinately. The findings further suggested that the temperature sensitivity of TO-336.vac affected the antibody induction in guinea pigs after subcutaneous inoculation. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. [Bacterial spore--a new vaccine vehicle--a review].

    Science.gov (United States)

    Wang, Yanchun; Zhang, Zhaoshan

    2008-03-01

    Bacterial spores are robust and dormant life forms with formidable resistance properties. Spores of the genus Bacillus have been used for a long time as probiotics for oral bacteriotherapy both in humans and animals. Recently, genetically modified B. subtilis spores and B. anthracis spores have been used as indestructible delivery vehicles for vaccine antigens. They were used as vaccine vehicles or spore vaccine for oral immunization against tetanus and anthrax, and the results were very exciting. Unlike many second generation vaccine systems currently under development, bacterial spores offer heat stability and the flexibility for genetic manipulation. At the same time, they can elicit mucosal immune response by oral and nasal administration. This review focuses on the use of recombinant spores as vaccine delivery vehicles.

  9. Adaptation of the spore discharge mechanism in the basidiomycota.

    Directory of Open Access Journals (Sweden)

    Jessica L Stolze-Rybczynski

    Full Text Available Spore discharge in the majority of the 30,000 described species of Basidiomycota is powered by the rapid motion of a fluid droplet, called Buller's drop, over the spore surface. In basidiomycete yeasts, and phytopathogenic rusts and smuts, spores are discharged directly into the airflow around the fungal colony. Maximum discharge distances of 1-2 mm have been reported for these fungi. In mushroom-forming species, however, spores are propelled over much shorter ranges. In gilled mushrooms, for example, discharge distances of <0.1 mm ensure that spores do not collide with opposing gill surfaces. The way in which the range of the mechanism is controlled has not been studied previously.In this study, we report high-speed video analysis of spore discharge in selected basidiomycetes ranging from yeasts to wood-decay fungi with poroid fruiting bodies. Analysis of these video data and mathematical modeling show that discharge distance is determined by both spore size and the size of the Buller's drop. Furthermore, because the size of Buller's drop is controlled by spore shape, these experiments suggest that seemingly minor changes in spore morphology exert major effects upon discharge distance.This biomechanical analysis of spore discharge mechanisms in mushroom-forming fungi and their relatives is the first of its kind and provides a novel view of the incredible variety of spore morphology that has been catalogued by traditional taxonomists for more than 200 years. Rather than representing non-selected variations in micromorphology, the new experiments show that changes in spore architecture have adaptive significance because they control the distance that the spores are shot through air. For this reason, evolutionary modifications to fruiting body architecture, including changes in gill separation and tube diameter in mushrooms, must be tightly linked to alterations in spore morphology.

  10. Bacillus cereus spore formation, structure and germination

    NARCIS (Netherlands)

    Vries, de Y.P.

    2006-01-01

    Bacterial spores arespecializeddifferentiated celltypes for

  11. Spore membrane(s) as the site of damage within heated Clostridium perfringens spores.

    Science.gov (United States)

    Flowers, R S; Adams, D M

    1976-02-01

    Clostridium perfringens spores were injured by ultrahigh-temperature treatment at 105 C for 5 min. Injury was manifested as an increased sensitivity to polymyxin and neomycin. Since many of the survivors could not germinate normally the ultrahigh-temperature-treated spores were sensitized to and germinated by lysozyme. Polymyxin reportedly acts upon the cell membrane. Neomycin may inhibit protein synthesis and has surface-active properties. Injured spores were increasingly sensitive to known surface-active agents, sodium lauryl sulfate, sodium deoxycholate, and Roccal, a quaternary ammonium compound. Injured spores sensitive to polymyxin and neomycin also were osmotically fragile and died during outgrowth in a liquid medium unless the medium was supplemented with 20% sucrose, 10% dextran, or 10% polyvinylpyrrolidone. The results suggested that a spore structure destined to become cell membrane or cell wall was the site of injury. Repair of injury during outgrowth in the presence of protein, deoxyribonucleic acid, ribonucleic acid and cell wall synthesis inhibitors was consistent with this hypothesis.

  12. Spatial variations of soil respiration and temperature sensitivity along a steep slope of the semiarid Loess Plateau.

    Science.gov (United States)

    Sun, Qiqi; Wang, Rui; Hu, Yaxian; Yao, Lunguang; Guo, Shengli

    2018-01-01

    The spatial heterogeneity of soil respiration and its temperature sensitivity pose a great challenge to accurately estimate the carbon flux in global carbon cycling, which has primarily been researched in flatlands versus hillslope ecosystems. On an eroded slope (35°) of the semiarid Loess Plateau, soil respiration, soil moisture and soil temperature were measured in situ at upper and lower slope positions in triplicate from 2014 until 2016, and the soil biochemical and microbial properties were determined. The results showed that soil respiration was significantly greater (by 44.2%) at the lower slope position (2.6 μmol m-2 s-1) than at the upper slope position, as were soil moisture, carbon, nitrogen fractions and root biomass. However, the temperature sensitivity was 13.2% greater at the upper slope position than at the lower slope position (P < 0.05). The soil fungal community changed from being Basidiomycota-dominant at the upper slope position to being Zygomycota-dominant at the lower slope position, corresponding with increased β-D-glucosidase activity at the upper slope position than at the lower slope position. We concluded that soil respiration was enhanced by the greater soil moisture, root biomass, carbon and nitrogen contents at the lower slope position than at the upper slope position. Moreover, the increased soil respiration and decreased temperature sensitivity at the lower slope position were partially due to copiotrophs replacing oligotrophs. Such spatial variations along slopes must be properly accounted for when estimating the carbon budget and feedback of future climate change on hillslope ecosystems.

  13. Upconverting PAAm/PNIPAM/NaYF{sub 4}:Yb:Er hydrogel with enhanced luminescence temperature sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jiachang; He, Benzhao; Cheng, Zehong; Zhou, Li, E-mail: zhouli@glut.edu.cn

    2015-04-15

    We present a one-step approach to combine the functional features of upconverting NaYF{sub 4}:Yb:Er nanoparticles and thermosensitive poly(N-isopropylacrylamide) (PNIPAM) for luminescence thermometry. Dual-functional hydrogel that simultaneously possesses strong upconversion luminescence (UL) and temperature responsibility was fabricated based on the crosslinking of poly(acrylamide) in the presence of PNIPAM and NaYF{sub 4}:Yb:Er nanoparticles. The obtained hydrogel exhibited reversibly temperature-dependent UL and highly enhanced sensibility. The luminescence temperature sensitivity reached 1.9% per °C and 0.7% per °C in the range of 27–33 °C and 35–45 °C, respectively. The maximum sensitivity could even reach 26.5% per °C in the range of 33–35 °C. Considering the facile fabrication process and fine luminescence thermometry performance, this study thus opens up new opportunities for preparing highly sensitive temperature sensors. - Highlights: • One-step fabrication of upconverting and thermosensitve PAAm/PNIPAM/NaYF{sub 4}:Yb:Er hydrogel is reported. • The combination of functional features of NaYF{sub 4}:Yb:Er upconversion nanoparticles (UCNPs) and thermosensitve PNIPAM can efficiently enhance the luminescence temperature sensitivity of UCNPs. • The luminescence temperature sensitivity of hydrogel can respectively reach 1.9% per °C and 0.7% per °C in the range of 27–33 °C and 35–45 °C. • The maximum sensitivity can even reach 26.5% per °C in range of 33–35 °C.

  14. Geographical pattern in first bloom variability and its relation to temperature sensitivity in the USA and China.

    Science.gov (United States)

    Wang, Huanjiong; Ge, Quansheng; Dai, Junhu; Tao, Zexing

    2015-08-01

    Advance in spring plant phenology over the last several decades has been found in all continents of the Northern Hemisphere. Compared to the studies detecting phenological trends, the studies investigating the geographical pattern of phenological variability (including mean date and magnitude of variability) are rather limited. In this study, we analyzed spatial pattern of mean date and standard deviation (SD) of first bloom date (FBD) time series (≥15 years) for black locust (Robinia pseudoacacia) at 22 stations in China, common lilac (Syringa vulgaris) at 79 stations in the Western US and Chinese lilac (Syringa chinensis) at 45 stations in the Eastern US. Subsequently, the impact of geographical factors (latitude, longitude, and altitude) on the mean date and SD was quantified by using the multiple regression analysis method. Meanwhile, the relationship between FBD variability and temperature sensitivity of FBD was examined. Results showed that the mean FBD highly depended on geographical factors for all the three species. Compared to the mean date, the dependence of SD of FBD time series on geographical factors was weaker. The geographical factors could only explain 13 to 31 % of spatial variance in SD of FBD. The negative regression coefficients of latitude (P < 0.05 except black locust) indicated that FBD is more variable at lower latitude. At most of stations, significant and negative correlations between FBD and preseason temperature on interannual scale were found, but the temperature sensitivity varied among different stations. The magnitude of temperature sensitivity decreased with increasing latitude. In general, the locations at lower latitude had earlier and more variable spring phenophase and showed stronger phenological response to climate change than the locations at higher latitude.

  15. Mucosal delivery of antigens using adsorption to bacterial spores.

    Science.gov (United States)

    Huang, Jen-Min; Hong, Huynh A; Van Tong, Hoang; Hoang, Tran H; Brisson, Alain; Cutting, Simon M

    2010-01-22

    The development of new-generation vaccines has followed a number of strategic avenues including the use of live recombinant bacteria. Of these, the use of genetically engineered bacterial spores has been shown to offer promise as both a mucosal as well as a heat-stable vaccine delivery system. Spores of the genus Bacillus are currently in widespread use as probiotics enabling a case to be made for their safety. In this work we have discovered that the negatively charged and hydrophobic surface layer of spores provides a suitable platform for adsorption of protein antigens. Binding can be promoted under conditions of low pH and requires a potent combination of electrostatic and hydrophobic interactions between spore and immunogen. Using appropriately adsorbed spores we have shown that mice immunised mucosally can be protected against challenge with tetanus toxin, Clostridium perfringens alpha toxin and could survive challenge with anthrax toxin. In some cases protection is actually greater than using a recombinant vaccine. Remarkably, killed or inactivated spores appear equally effective as live spores. The spore appears to present a bound antigen in its native conformation promoting a cellular (T(h)1-biased) response coupled with a strong antibody response. Spores then, should be considered as mucosal adjuvants, most similar to particulate adjuvants, by enhancing responses against soluble antigens. The broad spectrum of immune responses elicited coupled with the attendant benefits of safety suggest that spore adsorption could be appropriate for improving the immunogenicity of some vaccines as well as the delivery of biotherapeutic molecules.

  16. Bryophyte spore germinability is inhibited by peatland substrates

    Science.gov (United States)

    Bu, Zhao-Jun; Li, Zhi; Liu, Li-Jie; Sundberg, Sebastian; Feng, Ya-Min; Yang, Yun-He; Liu, Shuang; Song, Xue; Zhang, Xing-Lin

    2017-01-01

    Bryophyte substrates and species may affect spore germination through allelopathy. Polytrichum strictum is currently expanding in peatlands in north-eastern China - is this an effect of its superior spore germinability or do its gametophytes have a stronger allelopathic effect than do Sphagnum? We conducted a spore burial experiment to test the effect of species identity, substrate and water table depth (WTD) on spore germinability and bryophyte allelopathic effect with P. strictum and two Sphagnum species (S. palustre and S. magellanicum). After 5 months of burial during a growing season, the spores were tested for germinability. Allelopathic effect of bryophyte substrates was assessed by the difference between spore germinability after being stored inside or outside the substrates. After burial, more than 90% of the spores lost their germinability across all three species due to ageing and allelopathy. Spore germinability differed among species, where the spores in S. palustre had a higher germination frequency than those in P. strictum. The three bryophytes maintained a higher germinability in Sphagnum than in Polytrichum hummocks, probably due to a stronger allelopathic effect of P. strictum. Water table drawdown by 10 cm increased germinability by more than 60% across the three species. The study indicates that P. strictum does not possess an advantage regarding spore germination but rather its gametophytes have a stronger allelopathic effect. Due to the weaker inhibitive effect of Sphagnum gametophytes, P. strictum may have a potential establishment superiority over Sphagnum in peatlands, in addition to a better drought tolerance, which may explain its current expansion.

  17. No evidence for a Ganoderma spore dispersal mutualism in an obligate spore-feeding beetle Zearagytodes maculifer.

    Science.gov (United States)

    Kadowaki, Kohmei; Leschen, Richard A B; Beggs, Jacqueline R

    2011-08-01

    The role of spore dispersal mutualism remains equivocal in many fungus-insect assemblages. We tested experimentally whether an obligate spore-feeding beetle Zearagytodes maculifer has a mutualistic relationship with its host bracket fungus Ganoderma cf. applanatum via spore dispersal. We asked three specific questions: (1) whether or not Ganoderma spore germination rate is increased via beetle digestive activity and (2) is dependent on temperature and sporocarp identity. Spore germination rates were examined in 2×3×2 factorial experiments (spores consumed by beetles or not×temperature 20, 25, and 30°C×two independent pairs of sporocarp-beetle populations) replicated five times in an array of 60 experimental cultures. Analysis showed that consumption by beetles significantly reduced germination rate of Ganoderma spores. The effect of temperature was modulated by the effect of individual sporocarp, and was overridden by beetle feeding. Microscopic analysis revealed that spores from beetle faecal pellets exhibited extensive damage to their thin outer walls (pellicles) and thick inner walls, as well as significant loss of cytoplasm, while control spores were intact. The overall evidence argued against our spore dispersal mutualism hypothesis, suggesting that Z. maculifer can potentially exert a negative, if vanishingly small, fitness effect on its host fungus G. cf. applanatum. Copyright © 2011 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  18. Reusable temperature-sensitive luminescent material based on vitrified film of europium(III) β-diketonate complex

    Science.gov (United States)

    Lapaev, Dmitry V.; Nikiforov, Victor G.; Lobkov, Vladimir S.; Knyazev, Andrey A.; Galyametdinov, Yury G.

    2018-01-01

    We have proposed a novel temperature-sensitive luminescent material which is a 20 μm thick vitrified film (sandwiched between two quartz plates) fabricated from an amorphous powder of a mesogenic europium(III) β-diketonate complex through a melt-processing technique. The film photoexcited by a 337 nm pulsed nitrogen laser displays a typical Eu3+ ion luminescence bands with the strongest peak at 612 nm and with the decay time of 537 μs at 298 K. It is obtained that both the mean luminescence intensity and the luminescence decay time at 612 nm decrease significantly with temperature increasing from 298 to 348 K; the average values of the relative and absolute temperature sensitivities of the luminescence decay time in the range of 298-348 K are -1.2%·K-1 and -6.5 μs·K-1, respectively. The thermal quenching mechanism of the luminescent properties was analyzed and discussed. The experiments showed that, the luminescent properties of the film is insensitive to oxygen, the film is photostable under UV light, there is full reversibility of the temperature-dependent luminescence intensity and the decay time, and the high luminescence brightness of the film can be observed with violet light excitation. These factors indicated that the film is promising material for reusable luminescent thermometers, suitable for long-term monitoring in the range of 298-348 K.

  19. Temperature Oscillations, Complex Oscillations, and Elimination of Extraordinary Temperature Sensitivity in the Iodate-Sulfite-Thiosulfate Flow System

    Science.gov (United States)

    Liu, Haimiao; Xie, Jingxuan; Yuan, Ling; Gao, Qingyu

    2009-09-01

    Temperature oscillations and complex pH oscillations in the IO3--SO32--S2O32- system were observed in a continuously flow stirred tank reactor. During one period of oscillation, the temperature increases rapidly while the pH shows an extremely sharp change. High-amplitude pH oscillations undergo 11 complex oscillations (LS, oscillations with L large peaks and S small peaks per period) to another kind of higher-amplitude regular oscillations upon increasing the concentration of sulfite step by step. Importantly, the longstanding experimental phenomena, the extraordinary temperature sensitivity of oscillatory behavior reported 20 years ago by Rábai and Beck, can be eliminated by premixing of sulfite and sulfuric acid before entering into the reactor, avoiding local acidification, which brings out fluctuation and temperature sensitivity. The temperature oscillations can be understood by taking into account the interaction between thermal effect of various reactions and heat transfer. Experimental observations, both temperature oscillations and 11-type pH oscillations, are reproduced with a four-step Horváth model by addition of an energy-balance equation. This new detailed dynamical behavior would have potential applications in designing complex chemical waves and pH responsive gels with rhythmical motion.

  20. A study of Ganoderma lucidum spores by FTIR microspectroscopy

    Science.gov (United States)

    Wang, Xin; Chen, Xianliang; Qi, Zeming; Liu, Xingcun; Li, Weizu; Wang, Shengyi

    2012-06-01

    In order to obtain unique information of Ganoderma lucidum spores, FTIR microspectroscopy was used to study G. lucidum spores from Anhui Province (A), Liaoning Province (B) and Shangdong Province (C) of China. IR micro-spectra were acquired with high-resolution and well-reproducibility. The IR spectra of G. lucidum spores from different areas were similar and mainly made up of the absorption bands of polysaccharide, sterols, proteins, fatty acids, etc. The results of curve fitting indicated the protein secondary structures were dissimilar among the above G. lucidum spores. To identify G. lucidum spores from different areas, the H1078/H1640 value might be a potentially useful factor, furthermore FTIR microspectroscopy could realize this identification efficiently with the help of hierarchical cluster analysis. The result indicates FTIR microspectroscopy is an efficient tool for identification of G. lucidum spores from different areas. The result also suggests FTIR microspectroscopy is a potentially useful tool for the study of TCM.

  1. Modeling Radiation Effectiveness for Inactivation of Bacillus Spores

    Science.gov (United States)

    2015-09-17

    MODELING RADIATION EFFECTIVENESS FOR INACTIVATION OF BACILLUS SPORES DISSERTATION Emily A. Knight, Major, USAF AFIT-ENC-DS-15-S-001 DEPARTMENT OF THE...not subject to copyright protection in the United States. AFIT-ENC-DS-15-S-001 MODELING RADIATION EFFECTIVENESS FOR INACTIVATION OF BACILLUS SPORES...EFFECTIVENESS FOR INACTIVATION OF BACILLUS SPORES Emily A. Knight, B.A., M.S. Major, USAF Committee Membership: Dr. William P. Baker Chair Dr. Larry W

  2. Chitinolytic activity in viable spores of encephalitozoon species

    OpenAIRE

    Schottelius,J; Hünger,F; Schüler,Th; Gonçalves da Costa,SC

    2000-01-01

    By employing 4-methylumbelliferyl-beta-D-NN',N"-triacetylchitotriose substrate in a semi quantitative assay, chitinolytic activity in viable spores of Encephalitozoon cuniculi and E. intestinalis was detected and dependence on reaction time, spore concentration, concentration of substrate and temperature were demonstrated. It was possible to block the chitinolytic activity by chitin hydrolysate. By incubation at 80°C for 10 min or at 55°C for 20 min the spores were loosing the chitinolytic ac...

  3. Hydration, phase separation and nonlinear rheology of temperature-sensitive water-soluble polymers

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Fumihiko; Koga, Tsuyoshi [Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510 (Japan); Kaneda, Isamu [Department of Food Science, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501 (Japan); Winnik, Francoise M, E-mail: ftanaka@phys.polym.kyoto-u.ac.jp [Department of Chemistry and Faculty of Pharmacy, University of Montreal, Montreal, H3C 3J7 (Canada)

    2011-07-20

    The collapse of a poly(N-isopropylacrylamide) (PNIPAM) chain upon heating and the phase diagrams of aqueous PNIPAM solutions with a very flat lower critical solution temperature (LCST) phase separation line are theoretically studied on the basis of cooperative dehydration (simultaneous dissociation of bound water molecules in a group of correlated sequence), and compared with the experimental observation of temperature-induced coil-globule transition by light scattering methods. The transition becomes sharper with the cooperativity parameter {sigma} of hydration. The reentrant coil-globule-coil transition and cononsolvency in a mixed solvent of water and methanol are also studied from the viewpoint of competitive hydrogen bonds between polymer-water and polymer-methanol. The downward shift of the cloud-point curves (LCST cononsolvency) with the mol fraction of methanol due to the competition is calculated and compared with the experimental data. Aqueous solutions of hydrophobically modified PNIPAM carrying short alkyl chains at both chain ends (telechelic PNIPAM) are theoretically and experimentally studied. The LCST of these solutions is found to shift downward along the sol-gel transition curve as a result of end-chain association (association-induced phase separation), and separate from the coil-globule transition line. Associated structures in the solution, such as flower micelles, mesoglobules, and higher fractal assembly, are studied by ultra small-angle neutron scattering with theoretical modeling of the scattering function. Dynamic-mechanical modulus, nonlinear stationary viscosity, and stress build-up in start-up shear flows of the associated networks are studied on the basis of the affine and non-affine transient network theory. The molecular conditions for thickening, strain hardening, and stress overshoot are found in terms of the nonlinear amplitude A of the chain tension and the tension-dissociation coupling constant g.

  4. Hydration, phase separation and nonlinear rheology of temperature-sensitive water-soluble polymers.

    Science.gov (United States)

    Tanaka, Fumihiko; Koga, Tsuyoshi; Kaneda, Isamu; Winnik, Françoise M

    2011-07-20

    The collapse of a poly(N-isopropylacrylamide) (PNIPAM) chain upon heating and the phase diagrams of aqueous PNIPAM solutions with a very flat lower critical solution temperature (LCST) phase separation line are theoretically studied on the basis of cooperative dehydration (simultaneous dissociation of bound water molecules in a group of correlated sequence), and compared with the experimental observation of temperature-induced coil-globule transition by light scattering methods. The transition becomes sharper with the cooperativity parameter σ of hydration. The reentrant coil-globule-coil transition and cononsolvency in a mixed solvent of water and methanol are also studied from the viewpoint of competitive hydrogen bonds between polymer-water and polymer-methanol. The downward shift of the cloud-point curves (LCST cononsolvency) with the mol fraction of methanol due to the competition is calculated and compared with the experimental data. Aqueous solutions of hydrophobically modified PNIPAM carrying short alkyl chains at both chain ends (telechelic PNIPAM) are theoretically and experimentally studied. The LCST of these solutions is found to shift downward along the sol-gel transition curve as a result of end-chain association (association-induced phase separation), and separate from the coil-globule transition line. Associated structures in the solution, such as flower micelles, mesoglobules, and higher fractal assembly, are studied by ultra small-angle neutron scattering with theoretical modeling of the scattering function. Dynamic-mechanical modulus, nonlinear stationary viscosity, and stress build-up in start-up shear flows of the associated networks are studied on the basis of the affine and non-affine transient network theory. The molecular conditions for thickening, strain hardening, and stress overshoot are found in terms of the nonlinear amplitude A of the chain tension and the tension-dissociation coupling constant g.

  5. Chitinolytic activity in viable spores of encephalitozoon species

    Directory of Open Access Journals (Sweden)

    J Schottelius

    2000-10-01

    Full Text Available By employing 4-methylumbelliferyl-beta-D-NN',N"-triacetylchitotriose substrate in a semi quantitative assay, chitinolytic activity in viable spores of Encephalitozoon cuniculi and E. intestinalis was detected and dependence on reaction time, spore concentration, concentration of substrate and temperature were demonstrated. It was possible to block the chitinolytic activity by chitin hydrolysate. By incubation at 80°C for 10 min or at 55°C for 20 min the spores were loosing the chitinolytic activity. Incubation of the spores in trypsin reduced the chitinolytic activity. Cellulase activity could not be detected.

  6. Chitinolytic activity in viable spores of Encephalitozoon species.

    Science.gov (United States)

    Schottelius, J; Hünger, F; Schüler, T; Gonçalves da Costa, S C

    2000-01-01

    By employing 4-methylumbelliferyl-beta-D-NN',N"-triacetylchitotriose substrate in a semi quantitative assay, chitinolytic activity in viable spores of Encephalitozoon cuniculi and E. intestinalis was detected and dependence on reaction time, spore concentration, concentration of substrate and temperature were demonstrated. It was possible to block the chitinolytic activity by chitin hydrolysate. By incubation at 80 degrees C for 10 min or at 55 degrees C for 20 min the spores were loosing the chitinolytic activity. Incubation of the spores in trypsin reduced the chitinolytic activity. Cellulase activity could not be detected.

  7. Effects of Chlorine Dioxide on Spore Structural and Functional Properties

    National Research Council Canada - National Science Library

    Leighton, Terrance

    2003-01-01

    .... The experimental results described in this report were designed to test this hypothesis. Dormant bacterial endospores are highly birefringent due to the anhydrous nature of the spore cytoplasm...

  8. Effect of individual or combined treatment by γ-irradiation or temperature (high or low) on bacillus subtilis spores and its application for sterilization of ground beef

    International Nuclear Information System (INIS)

    El-Zawahry, Y.A.; Mostafa, S.A.; Awny, N.M.

    1986-01-01

    The combination of two lethal agents such as irradiation and temperature (high or sub zero) resulted in synergistic death or B. subtilis spores (as indicated by decrease in the thermal D-value). The extent of this synergism in killing a spore population depended mainly on the sequence on application of the two physical agents. Irradiation-temperature (high or sub zero) sequence killed more but injured less B. subtilis spores than temperature irradiation sequence or irradiation and temperature applied separately. Storage at -20 0 C killed more spores than storage at -2 0 C if carried after irradiation, while the reverse was true of storage was prior irradiation. An irradiation dose of 8 KGY followed by thermal exposure to 70 0 C for 1 hr is suggested for the sterilization of ground beef. Irradiation induced certain quantitative changes on the amino-N, protein-N, RNA and DNA of the first subcultures of irradiated spores with stimulatory effect at low irradiation doses and inhibitory effect at the high irradiation doses. This might explain the increased sensitivity of irradiated spores to subsequent exposure to unfavourable temperature (high or sub zero). Exposure of B. subtilis spore to 70 0 C induced a stimulation in the amino- and protein-N of the resulting cells while exposure to 80 0 C resulted in a significant decrease in the amino-N. The protein-N remained more or less the same

  9. Presenting Influenza A M2e Antigen on Recombinant Spores of Bacillus subtilis.

    Directory of Open Access Journals (Sweden)

    Tomasz Łęga

    Full Text Available Effective vaccination against influenza virus infection is a serious problem mainly due to antigenic variability of the virus. Among many of investigated antigens, the extracellular domain of the M2 protein (M2e features high homology in all strains of influenza A viruses and antibodies against M2e and is protective in animal models; this makes it a potential candidate for generation of a universal influenza vaccine. However, due to the low immunogenicity of the M2e, formulation of a vaccine based on this antigen requires some modification to induce effective immune responses. In this work we evaluated the possible use of Bacillus subtilis spores as a carrier of the Influenza A M2e antigen in mucosal vaccination. A tandem repeat of 4 consensus sequences coding for human-avian-swine-human M2e (M2eH-A-S-H peptide was fused to spore coat proteins and stably exposed on the spore surface, as demonstrated by the immunostaining of intact, recombinant spores. Oral immunization of mice with recombinant endospores carrying M2eH-A-S-H elicited specific antibody production without the addition of adjuvants. Bacillus subtilis endospores can serve as influenza antigen carriers. Recombinant spores constructed in this work showed low immunogenicity although were able to induce antibody production. The System of influenza antigen administration presented in this work is attractive mainly due to the omitting time-consuming and cost-intensive immunogen production and purification. Therefore modification should be made to increase the immunogenicity of the presented system.

  10. Airborne movement of anthrax spores from carcass sites in the Etosha National Park, Namibia.

    Science.gov (United States)

    Turnbull, P C; Lindeque, P M; Le Roux, J; Bennett, A M; Parks, S R

    1998-04-01

    Tests for airborne movement of anthrax spores downwind from three heavily contaminated carcass sites were carried out under a range of wind conditions. Anthrax spores were detected in just three of 43 cyclone or gelatin filter air samples taken at distances of 6, 12 and 18 m from the sites. In addition, nine positives resulted during sampling sessions in which the site was mechanically disturbed, with a further five positives being found in sessions subsequent to those in which the site had been disturbed. The three positive samples not related to man-made disturbance were associated with the highest winds experienced during the study. Despite colony counts exceeding 100 on the culture plates in three instances, calculations showed that these represented very low worst case probable spore inhalation rates for animals or humans exposed to such levels. The low number of positives, the clear pattern of rapidly declining numbers of anthrax spores with distance downwind from the centres of the sites apparent on settle plates, and the persisting levels of contamination despite wind and rain, collectively suggest that the anthrax spores were associated with fairly heavy particles, although this was not seen by electron microscopy on soil samples from the sites. Overall, the findings are interpreted as indicating that it is very unlikely that Etosha animals contract anthrax by the inhalation route while simply in transit near or across a carcass site. The significance of the observations in relation to weather conditions in the Etosha, other studies on particulate aerosols in the region, and reports of long-distance airborne movement of microbes, is discussed.

  11. Prevalence, intensity and complications of Microsporidium spores amongst HIV-positive hospital patients in Ilorin, Nigeria

    Directory of Open Access Journals (Sweden)

    Amase Nyamngee

    2013-11-01

    Full Text Available Background: Microsporidiasis, which is of great concern for immunocompromised patients, is poorly studied in developing countries. Objectives: A study was carried out amongst HIV-positive hospital patients and HIV-negative hospital controls in Ilorin, Nigeria, between January 2009 and July 2010 to determine the prevalence and intensity of Microsporidium spores and the complications associated with their presence. Method: Stool samples from 750 HIV-positive patients and 375 HIV-negative patients were studied using the Chromotrope-2R staining technique. Determination of CD4+ count was performed on the Partec Cyflow SL-3 CD4/8 instrument. Intensity of spores was determined by counting the total number of the spores in a 10 μl stained smear of stool. Images were captured with Phenix Microimage Analysis Software and data obtained were analysed using the Statistical Package for the Social Sciences. Results: The prevalence of Microsporidium isolates amongst the HIV-positive hospital patients was significantly higher (42.4% than amongst the HIV-negative controls (19.2%(p < 0.05. The intensity of microsporidial spores amongst HIV-positive hospital patients was also significantly higher than amongst the controls (p < 0.05. However, the difference in the intensity of spores amongst HIV-positive patients who were on antiretroviral therapy(n = 411 and those who were not (n = 339 was not significant (p = 0.236. Microsporidiasis in HIV infection infection was common amongst patients with with low CD4+ counts, diarrhoea, body rashes and cough. Conclusion: Both the prevalence and intensity of Microsporidiasis are high amongst HIV-positive hospital patients; campaigns to promote awareness, prevention and control are required. Laboratory testing for microsporidia in HIV patients should be performed routinely so as to identify the organism for prompt medical attention.

  12. Action of temperature-sensitive mutants of myeloproliferative sarcoma virus suggests that fibroblast-transforming and hematopoietic transforming viral properties are related.

    Science.gov (United States)

    Ostertag, W; Freshney, M; Vehmeyer, K; Jasmin, C; Rutter, G

    1984-01-01

    The myeloproliferative sarcoma virus is molecularly related to the Moloney sarcoma virus (Pragnell et al., J. Virol. 38:952-957, 1981), but causes both fibroblast transformation in vitro and leukemic changes--including spleen focus formation--in adult mice. The fibroblast transforming properties of myeloproliferative sarcoma virus were used to select viral temperature-sensitive mutants at 39.5 degrees C, the nonpermissive temperature. These mutants are temperature sensitive in the maintenance of the transformed state. This was also shown by cytoskeletal changes of the infected cells at permissive and nonpermissive temperatures. Viruses released from cells maintained at both the permissive and nonpermissive temperature are temperature sensitive in fibroblast transformation functions. All temperature-sensitive mutants show only a low reversion rate to wild-type transforming function. The myeloproliferative sarcoma virus temperature-sensitive mutants are inefficient in causing leukemic transformation (spleen enlargement, focus formation) in mice at the normal temperature. A method to maintain a low body temperature (33 to 34 degrees C) in mice is described. One temperature-sensitive mutant was checked at low body temperature and did not induce leukemia. These data thus indicate that the same or related viral functions are responsible for hematopoietic and fibroblast transformation.

  13. Spore-Forming Bacteria that Resist Sterilization

    Science.gov (United States)

    LaDuc, Myron; Venkateswaran, Kasthuri

    2003-01-01

    A report presents a phenotypic and genotypic characterization of a bacterial species that has been found to be of the genus Bacillus and has been tentatively named B. odysseensis because it was isolated from surfaces of the Mars Odyssey spacecraft as part of continuing research on techniques for sterilizing spacecraft to prevent contamination of remote planets by terrestrial species. B. odysseensis is a Gram-positive, facultatively anaerobic, rod-shaped bacterium that forms round spores. The exosporium has been conjectured to play a role in the elevated resistance to sterilization. Research on the exosporium is proposed as a path toward improved means of sterilization, medical treatment, and prevention of biofouling.

  14. Temperature sensitivity of total soil respiration and its heterotrophic and autotrophic components in six vegetation types of subtropical China.

    Science.gov (United States)

    Yu, Shiqin; Chen, Yuanqi; Zhao, Jie; Fu, Shenglei; Li, Zhian; Xia, Hanping; Zhou, Lixia

    2017-12-31

    The temperature sensitivity of soil respiration (Q 10 ) is a key parameter for estimating the feedback of soil respiration to global warming. The Q 10 of total soil respiration (R t ) has been reported to have high variability at both local and global scales, and vegetation type is one of the most important drivers. However, little is known about how vegetation types affect the Q 10 of soil heterotrophic (R h ) and autotrophic (R a ) respirations, despite their contrasting roles in soil carbon sequestration and ecosystem carbon cycles. In the present study, five typical plantation forests and a naturally developed shrub and herb land in subtropical China were selected for investigation of soil respiration. Trenching was conducted to separate R h and R a in each vegetation type. The results showed that both R t and R h were significantly correlated with soil temperature in all vegetation types, whereas R a was significantly correlated with soil temperature in only four vegetation types. Moreover, on average, soil temperature explained only 15.0% of the variation in R a in the six vegetation types. These results indicate that soil temperature may be not a primary factor affecting R a . Therefore, modeling of R a based on its temperature sensitivity may not always be valid. The Q 10 of R h was significantly affected by vegetation types, which indicates that the response of the soil carbon pool to climate warming may vary with vegetation type. In contrast, differences in neither the Q 10 of R t nor that of R a among these vegetation types were significant. Additionally, variation in the Q 10 of R t among vegetation types was negatively related to fine root biomass, whereas the Q 10 of R h was mostly related to total soil nitrogen. However, the Q 10 of R a was not correlated with any of the environmental variables monitored in this study. These results emphasize the importance of independently studying the temperature sensitivity of R t and its heterotrophic and

  15. Comparative analysis of the concentration of fungal spores in the air of Lublin and Rzeszów (Eastern Poland

    Directory of Open Access Journals (Sweden)

    Idalia Kasprzyk

    2012-12-01

    Full Text Available Studies of the concentration of fungal spores were carried out in the cities of Lublin and Rzeszów simultaneously in 2002. At both sites the volumetric method of measurement was applied, using the Lanzoni VPPS 2000 trap. Only the allergenic taxa were analysed: Alternaria, Botrytis, Cladosporium, Drechslera type, Epicoccum, Torula, Stemphylium, Pithomyces, Polythrincium, and Ganoderma. The research showed considerable differences in the concentration and frequency of spores in the air at the sites compared. Higher mean concentrations of spores were usually observed in Lublin. Only for two taxa were the concentrations higher in Rzeszów. No significant differences were observed for the genus of Polythrincium and Torula. Also the lengths of periods of occurrence of the spores were determined using the 95% method. It was determined that the geobotanical conditions in Rzeszów have a positive effect on the lengthening of the presence of the spores in aeroplankton. The results of the observations were analysed statistically, which confirmed the occurrence of significant differences between the cities compared.

  16. A Streptomyces-specific member of the metallophosphatase superfamily contributes to spore dormancy and interaction with Aspergillus proliferans.

    Science.gov (United States)

    Lamp, Jessica; Weber, Maren; Cingöz, Gökhan; Ortiz de Orué Lucana, Darío; Schrempf, Hildgund

    2013-05-01

    We have identified, cloned and characterized a formerly unknown protein from Streptomyces lividans spores. The deduced protein belongs to a novel member of the metallophosphatase superfamily and contains a phosphatase domain and predicted binding sites for divalent ions. Very close relatives are encoded in the genomic DNA of many different Streptomyces species. As the deduced related homologues diverge from other known phosphatase types, we named the protein MptS (metallophosphatase type from Streptomyces). Comparative physiological and biochemical investigations and analyses by fluorescence microscopy of the progenitor strain, designed mutants carrying either a disruption of the mptS gene or the reintroduced gene as fusion with histidine codons or the egfp gene led to the following results: (i) the mptS gene is transcribed in the course of aerial mycelia formation. (ii) The MptS protein is produced during the late stages of growth, (iii) accumulates within spores, (iv) functions as an active enzyme that releases inorganic phosphate from an artificial model substrate, (v) is required for spore dormancy and (vi) MptS supports the interaction amongst Streptomyces lividans spores with conidia of the fungus Aspergillus proliferans. We discuss the possible role(s) of MptS-dependent enzymatic activity and the implications for spore biology. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  17. Airborne fungal spores of Alternaria, meteorological parameters and predicting variables

    Science.gov (United States)

    Filali Ben Sidel, Farah; Bouziane, Hassan; del Mar Trigo, Maria; El Haskouri, Fatima; Bardei, Fadoua; Redouane, Abdelbari; Kadiri, Mohamed; Riadi, Hassane; Kazzaz, Mohamed

    2015-03-01

    Alternaria is frequently found as airborne fungal spores and is recognized as an important cause of respiratory allergies. The aerobiological monitoring of fungal spores was performed using a Burkard volumetric spore traps. To establish predicting variables for daily and weakly spore counts, a stepwise multiple regression between spore concentrations and independent variables (meteorological parameters and lagged values from the series of spore concentrations: previous day or week concentration (Alt t - 1) and mean concentration of the same day or week in other years ( C mean)) was made with data obtained during 2009-2011. Alternaria conidia are present throughout the year in the atmosphere of Tetouan, although they show important seasonal fluctuations. The highest levels of Alternaria spores were recorded during the spring and summer or autumn. Alternaria showed maximum daily values in April, May or October depending on year. When the spore variables of Alternaria, namely C mean and Alt t - 1, and meteorological parameters were included in the equation, the resulting R 2 satisfactorily predict future concentrations for 55.5 to 81.6 % during the main spore season and the pre-peak 2. In the predictive model using weekly values, the adjusted R 2 varied from 0.655 to 0.676. The Wilcoxon test was used to compare the results from the expected values and the pre-peak spore data or weekly values for 2012, indicating that there were no significant differences between series compared. This test showed the C mean, Alt t - 1, frequency of the wind third quadrant, maximum wind speed and minimum relative humidity as the most efficient independent variables to forecast the overall trend of this spore in the air.

  18. Airborne fungal spores of Alternaria, meteorological parameters and predicting variables.

    Science.gov (United States)

    Filali Ben Sidel, Farah; Bouziane, Hassan; Del Mar Trigo, Maria; El Haskouri, Fatima; Bardei, Fadoua; Redouane, Abdelbari; Kadiri, Mohamed; Riadi, Hassane; Kazzaz, Mohamed

    2015-03-01

    Alternaria is frequently found as airborne fungal spores and is recognized as an important cause of respiratory allergies. The aerobiological monitoring of fungal spores was performed using a Burkard volumetric spore traps. To establish predicting variables for daily and weakly spore counts, a stepwise multiple regression between spore concentrations and independent variables (meteorological parameters and lagged values from the series of spore concentrations: previous day or week concentration (Alt t - 1) and mean concentration of the same day or week in other years (C mean)) was made with data obtained during 2009-2011. Alternaria conidia are present throughout the year in the atmosphere of Tetouan, although they show important seasonal fluctuations. The highest levels of Alternaria spores were recorded during the spring and summer or autumn. Alternaria showed maximum daily values in April, May or October depending on year. When the spore variables of Alternaria, namely C mean and Alt t - 1, and meteorological parameters were included in the equation, the resulting R (2) satisfactorily predict future concentrations for 55.5 to 81.6 % during the main spore season and the pre-peak 2. In the predictive model using weekly values, the adjusted R (2) varied from 0.655 to 0.676. The Wilcoxon test was used to compare the results from the expected values and the pre-peak spore data or weekly values for 2012, indicating that there were no significant differences between series compared. This test showed the C mean, Alt t - 1, frequency of the wind third quadrant, maximum wind speed and minimum relative humidity as the most efficient independent variables to forecast the overall trend of this spore in the air.

  19. Large temperature sensitivity of fiber-optic extrinsic Fabry-Perot interferometer based on polymer-filled glass capillary

    Science.gov (United States)

    Zhang, Guilin; Yang, Minghong; Wang, Min

    2013-12-01

    A novel and low cost fiber-optic extrinsic Fabry-Perot interferometer (EFPI) is proposed. The EFPI is fabricated at the fiber tip by inserting a single mode fiber (SMF) into a partially polymer-filled glass capillary to form an air micro-cavity, which can be precisely controlled with a three-dimensional translation stage. The optimal EFPI has a loss less than 10 dB and a fringe visibility more than 30 dB. Application of the EFPI for temperature measurement is experimentally demonstrated. Due to the high thermal expansion coefficient (TEC) of the polymer, the sensor exhibits a good linear response and large temperature sensitivity of ˜5.2 nm/°C, which is almost three orders larger than that of the current F-P temperature sensors. Therefore, it may be applied to the surrounding temperature sensing.

  20. Development and application of genetic sexing systems for the Mediterranean fruit fly based on a temperature sensitive lethal mutation

    International Nuclear Information System (INIS)

    Franz, G.; Willhoeft, U.; Kerremans, P.; Hendrichs, J.; Rendon, P.

    1997-01-01

    The present status in genetic sexing for the Mediterranean fruit fly is discussed. This includes the selection of the appropriate sexing gene (which determines the feasibility and practical applicability of the sexing system) as well as the selection of the appropriate Y-autosome translocation (which determines the stability of the sexing system). A temperature sensitive lethal mutation is used to eliminate females during the egg stage. This mutation in combination with new Y-autosome translocations allowed the construction of a genetic sexing strain, named VIENNA-42, that is stable enough for large scale mass rearing. Also described are the analysis of this strain under field cage and field conditions and, in preparation for large scale tests in Guatemala, the outcrossing of VIENNA-42 with genetic material from the target area. (author)

  1. A major QTL affects temperature sensitive adult lethality and inbreeding depression in life span in Drosophila melanogaster.

    DEFF Research Database (Denmark)

    Vermeulen, Corneel J.; Bijlsma, R.; Loeschcke, Volker

    2008-01-01

    of inbreeding effects in specific traits, such as age-specific mortality and life span, provide a good starting point, as a limited set of genes is expected to be involved. Results Here we report on a QTL mapping study on inbreeding related and temperature sensitive lethality in male Drosophila melanogaster...... and the molecular properties of genes that give rise to or modulate its deleterious effects is lacking. These questions warrant the detailed study of genetic loci giving rise to inbreeding depression. However, the complex and polygenic nature of general inbreeding depression makes this a daunting task. Study...... simple, being due mainly to a single recessive QTL on the left arm of chromosome 2. This locus colocalised with a QTL that conditioned variation in female life span, acting as an overdominant locus for this trait. Male life span was additionally affected by variation at the X-chromosome. Conclusion...

  2. Evolution of vertebrate transient receptor potential vanilloid 3 channels: opposite temperature sensitivity between mammals and western clawed frogs.

    Directory of Open Access Journals (Sweden)

    Shigeru Saito

    2011-04-01

    Full Text Available Transient Receptor Potential (TRP channels serve as temperature receptors in a wide variety of animals and must have played crucial roles in thermal adaptation. The TRP vanilloid (TRPV subfamily contains several temperature receptors with different temperature sensitivities. The TRPV3 channel is known to be highly expressed in skin, where it is activated by warm temperatures and serves as a sensor to detect ambient temperatures near the body temperature of homeothermic animals such as mammals. Here we performed comprehensive comparative analyses of the TRPV subfamily in order to understand the evolutionary process; we identified novel TRPV genes and also characterized the evolutionary flexibility of TRPV3 during vertebrate evolution. We cloned the TRPV3 channel from the western clawed frog Xenopus tropicalis to understand the functional evolution of the TRPV3 channel. The amino acid sequences of the N- and C-terminal regions of the TRPV3 channel were highly diversified from those of other terrestrial vertebrate TRPV3 channels, although central portions were well conserved. In a heterologous expression system, several mammalian TRPV3 agonists did not activate the TRPV3 channel of the western clawed frog. Moreover, the frog TRPV3 channel did not respond to heat stimuli, instead it was activated by cold temperatures. Temperature thresholds for activation were about 16 °C, slightly below the lower temperature limit for the western clawed frog. Given that the TRPV3 channel is expressed in skin, its likely role is to detect noxious cold temperatures. Thus, the western clawed frog and mammals acquired opposite temperature sensitivity of the TRPV3 channel in order to detect environmental temperatures suitable for their respective species, indicating that temperature receptors can dynamically change properties to adapt to different thermal environments during evolution.

  3. Seasonality, Rather than Nutrient Addition or Vegetation Types, Influenced Short-Term Temperature Sensitivity of Soil Organic Carbon Decomposition.

    Science.gov (United States)

    Qian, Yu-Qi; He, Feng-Peng; Wang, Wei

    2016-01-01

    The response of microbial respiration from soil organic carbon (SOC) decomposition to environmental changes plays a key role in predicting future trends of atmospheric CO2 concentration. However, it remains uncertain whether there is a universal trend in the response of microbial respiration to increased temperature and nutrient addition among different vegetation types. In this study, soils were sampled in spring, summer, autumn and winter from five dominant vegetation types, including pine, larch and birch forest, shrubland, and grassland, in the Saihanba area of northern China. Soil samples from each season were incubated at 1, 10, and 20°C for 5 to 7 days. Nitrogen (N; 0.035 mM as NH4NO3) and phosphorus (P; 0.03 mM as P2O5) were added to soil samples, and the responses of soil microbial respiration to increased temperature and nutrient addition were determined. We found a universal trend that soil microbial respiration increased with increased temperature regardless of sampling season or vegetation type. The temperature sensitivity (indicated by Q10, the increase in respiration rate with a 10°C increase in temperature) of microbial respiration was higher in spring and autumn than in summer and winter, irrespective of vegetation type. The Q10 was significantly positively correlated with microbial biomass and the fungal: bacterial ratio. Microbial respiration (or Q10) did not significantly respond to N or P addition. Our results suggest that short-term nutrient input might not change the SOC decomposition rate or its temperature sensitivity, whereas increased temperature might significantly enhance SOC decomposition in spring and autumn, compared with winter and summer.

  4. Vegetation types alter soil respiration and its temperature sensitivity at the field scale in an estuary wetland.

    Science.gov (United States)

    Han, Guangxuan; Xing, Qinghui; Luo, Yiqi; Rafique, Rashad; Yu, Junbao; Mikle, Nate

    2014-01-01

    Vegetation type plays an important role in regulating the temporal and spatial variation of soil respiration. Therefore, vegetation patchiness may cause high uncertainties in the estimates of soil respiration for scaling field measurements to ecosystem level. Few studies provide insights regarding the influence of vegetation types on soil respiration and its temperature sensitivity in an estuary wetland. In order to enhance the understanding of this issue, we focused on the growing season and investigated how the soil respiration and its temperature sensitivity are affected by the different vegetation (Phragmites australis, Suaeda salsa and bare soil) in the Yellow River Estuary. During the growing season, there were significant linear relationships between soil respiration rates and shoot and root biomass, respectively. On the diurnal timescale, daytime soil respiration was more dependent on net photosynthesis. A positive correlation between soil respiration and net photosynthesis at the Phragmites australis site was found. There were exponential correlations between soil respiration and soil temperature, and the fitted Q10 values varied among different vegetation types (1.81, 2.15 and 3.43 for Phragmites australis, Suaeda salsa and bare soil sites, respectively). During the growing season, the mean soil respiration was consistently higher at the Phragmites australis site (1.11 µmol CO2 m(-2) s(-1)), followed by the Suaeda salsa site (0.77 µmol CO2 m(-2) s(-1)) and the bare soil site (0.41 µmol CO2 m(-2) s(-1)). The mean monthly soil respiration was positively correlated with shoot and root biomass, total C, and total N among the three vegetation patches. Our results suggest that vegetation patchiness at a field scale might have a large impact on ecosystem-scale soil respiration. Therefore, it is necessary to consider the differences in vegetation types when using models to evaluate soil respiration in an estuary wetland.

  5. Surgical implantation of temperature-sensitive transmitters and data-loggers to record body temperature in koalas (Phascolarctos cinereus).

    Science.gov (United States)

    Adam, D; Johnston, S D; Beard, L; Nicholson, V; Lisle, A; Gaughan, J; Larkin, R; Theilemann, P; Mckinnon, A; Ellis, W

    2016-01-01

    Under predicted climate change scenarios, koala distribution in Australia is expected to be adversely affected. Recent studies have attempted to identify suitable habitat, based on models of bioclimatic regions, but to more accurately reflect the thermal tolerance and behavioural adaptations of the various regional populations, the koala's response to periods of heat stress will need to be investigated at the individual animal level. To explore the safety and suitability of temperature-sensitive intra-abdominal implants for monitoring core body temperature in the koala. A temperature-sensitive radio transmitter and thermal iButton data-logger, waxed together as a package, were surgically implanted into the abdominal cavity of four captive koalas. In one animal the implant was tethered and in the other three, it was left free-floating. After 3 months, the implants were removed and all four koalas recovered without complications. The tethering of the package in the one koala resulted in minor inflammation and adhesion, so this practice was subsequently abandoned. The free-floating deployments were complication-free and revealed a diurnal body temperature rhythm, with daily ranges of 0.4-2.8°C. The minimum recorded body temperature was 34.2°C and the maximum was 37.7°C. The difference in the readings obtained from the transmitters and iButtons never exceeded 0.3°C. The suitability of the surgical approach was confirmed, from both the animal welfare and data collection points of view. © 2016 Australian Veterinary Association.

  6. Vegetation types alter soil respiration and its temperature sensitivity at the field scale in an estuary wetland.

    Directory of Open Access Journals (Sweden)

    Guangxuan Han

    Full Text Available Vegetation type plays an important role in regulating the temporal and spatial variation of soil respiration. Therefore, vegetation patchiness may cause high uncertainties in the estimates of soil respiration for scaling field measurements to ecosystem level. Few studies provide insights regarding the influence of vegetation types on soil respiration and its temperature sensitivity in an estuary wetland. In order to enhance the understanding of this issue, we focused on the growing season and investigated how the soil respiration and its temperature sensitivity are affected by the different vegetation (Phragmites australis, Suaeda salsa and bare soil in the Yellow River Estuary. During the growing season, there were significant linear relationships between soil respiration rates and shoot and root biomass, respectively. On the diurnal timescale, daytime soil respiration was more dependent on net photosynthesis. A positive correlation between soil respiration and net photosynthesis at the Phragmites australis site was found. There were exponential correlations between soil respiration and soil temperature, and the fitted Q10 values varied among different vegetation types (1.81, 2.15 and 3.43 for Phragmites australis, Suaeda salsa and bare soil sites, respectively. During the growing season, the mean soil respiration was consistently higher at the Phragmites australis site (1.11 µmol CO2 m(-2 s(-1, followed by the Suaeda salsa site (0.77 µmol CO2 m(-2 s(-1 and the bare soil site (0.41 µmol CO2 m(-2 s(-1. The mean monthly soil respiration was positively correlated with shoot and root biomass, total C, and total N among the three vegetation patches. Our results suggest that vegetation patchiness at a field scale might have a large impact on ecosystem-scale soil respiration. Therefore, it is necessary to consider the differences in vegetation types when using models to evaluate soil respiration in an estuary wetland.

  7. Determination of fungal spore release from wet building materials

    DEFF Research Database (Denmark)

    Kildesø, J.; Wurtz, H.; Nielsen, Kristian Fog

    2003-01-01

    The release and transport of fungal spores from water-damaged building materials is a key factor for understanding the exposure to particles of fungal origin as a possible cause of adverse health effects associated to growth of fungi indoors. In this study, the release of spores from nine species...

  8. Bacterial Spores in Food : Survival, Emergence, and Outgrowth

    NARCIS (Netherlands)

    Wells-Bennik, Marjon H J; Eijlander, Robyn T; den Besten, Heidy M W; Berendsen, Erwin M; Warda, Alicja K; Krawczyk, Antonina O; Nierop Groot, Masja N; Xiao, Yinghua; Zwietering, Marcel H; Kuipers, Oscar P; Abee, Tjakko

    2016-01-01

    Spore-forming bacteria are ubiquitous in nature. The resistance properties of bacterial spores lie at the heart of their widespread occurrence in food ingredients and foods. The efficacy of inactivation by food-processing conditions is largely determined by the characteristics of the different types

  9. The Role of the Electrostatic Force in Spore Adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eunhyea [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Lee, Ida [University of Tennessee, Knoxville (UTK); Tsouris, Costas [ORNL

    2010-01-01

    Electrostatic force is investigated as one of the components of the adhesion force between Bacillus thuringiensis (Bt) spores and planar surfaces. The surface potentials of a Bt spore and a mica surface are experimentally obtained using a combined atomic force microscopy (AFM)-scanning surface potential microscopy technique. On the basis of experimental information, the surface charge density of the spores is estimated at 0.03 {micro}C/cm{sup 2} at 20% relative humidity and decreases with increasing humidity. The Coulombic force is introduced for the spore-mica system (both charged, nonconductive surfaces), and an electrostatic image force is introduced to the spore-gold system because gold is electrically conductive. The Coulombic force for spore-mica is repulsive because the components are similarly charged, while the image force for the spore-gold system is attractive. The magnitude of both forces decreases with increasing humidity. The electrostatic forces are added to other force components, e.g., van der Waals and capillary forces, to obtain the adhesion force for each system. The adhesion forces measured by AFM are compared to the estimated values. It is shown that the electrostatic (Coulombic and image) forces play a significant role in the adhesion force between spores and planar surfaces.

  10. Survival of Clostridium difficile spores at low water activity.

    Science.gov (United States)

    Deng, Kai; Talukdar, Prabhat K; Sarker, Mahfuzur R; Paredes-Sabja, Daniel; Torres, J Antonio

    2017-08-01

    Clostridium difficile is frequently found in meat and meat products. Germination efficiency, defined as colony formation, was previously investigated at temperatures found in meat handling and processing for spores of strain M120 (animal isolate), R20291 (human isolate), and DK1 (beef isolate). In this study, germination efficiency of these spore strains was assessed in phosphate buffered saline (PBS, a w ∼1.00), commercial beef jerky (a w ∼0.82/0.72), and a w -adjusted PBS (a w ∼0.82/0.72). Surface hydrophobicity was followed for spores stored in PBS. After three months and for all PBS a w levels tested, M120 and DK1 spores showed a ∼1 decimal reduction in colony formation but this was not the case when kept in beef jerky suggesting a protective food matrix effect. During storage, and with no significant a w effect, an increase in colony formation was observed for R20291 spores kept in PBS (∼2 decimal log increase) and beef jerky (∼1 decimal log increase) suggesting a loss of spore superdormancy. For all strains, no significant changes in spore surface hydrophobicity were observed after storage. Collectively, these results indicate that depending on the germination properties of C. difficile spores and the media properties, their germination efficiency may increase or decrease during long term food storage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Germination of Bacillus cereus spores adhered to stainless steel

    NARCIS (Netherlands)

    Hornstra, L.M.; Leeuw, de P.P.L.A.; Moezelaar, R.; Wolbert, E.J.H.; Vries, de Y.P.; Vos, de W.M.; Abee, T.

    2007-01-01

    Adhered spores of Bacillus cereus represent a significant part of the surface-derived contamination in processing equipment used in the dairy industry. As germinated spores lose their resistance capacities instantaneously, efficient germination prior to a cleaning in place treatment could aid to the

  12. Inhibition of spore germination of Alternaria tenuis by sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Couey, H.M.

    1962-08-01

    As a part of a continuing study of SO/sub 2/ fumigation of table grapes, the effect of SO/sub 2/ on spores of an isolate of A. tenuis Auct. causing decay of table grapes was determined. The amount of SO/sub 2/ required to inhibit completely spore germination depended on availability of moisture and the temperature. At 20/sup 0/C, wet spores required 20-min exposure to 100 ppm SO/sub 2/ to prevent germination, but spores equilibrated at 90% relative humidity (RH) required 10-min exposure to 1000 ppm SO/sub 2/. Dry spores at 60% RH were unaffected by a 20-min exposure to 4000 ppm SO/sub 2/. Increasing the temperature in the range 5-20/sup 0/C increased effectiveness of the SO/sub 2/ treatment. A comparison of Alternaria with Botrytis cinerea Fr. (studied earlier) showed that wet spores of these organisms were about equally sensitive to SO/sub 2/, but that dry Alternaria spores were more resistant to SO/sub 2/ than dry Botrytis spores under comparable conditions.

  13. Macroalgal spore dysfunction: ocean acidification delays and weakens adhesion.

    Science.gov (United States)

    Guenther, Rebecca; Miklasz, Kevin; Carrington, Emily; Martone, Patrick T

    2018-04-01

    Early life stages of marine organisms are predicted to be vulnerable to ocean acidification. For macroalgae, reproduction and population persistence rely on spores to settle, adhere and continue the algal life cycle, yet the effect of ocean acidification on this critical life stage has been largely overlooked. We explicitly tested the biomechanical impact of reduced pH on early spore adhesion. We developed a shear flume to examine the effect of reduced pH on spore attachment time and strength in two intertidal rhodophyte macroalgae, one calcified (Corallina vancouveriensis) and one noncalcified (Polyostea robusta). Reduced pH delayed spore attachment of both species by 40%-52% and weakened attachment strength in C. vancouveriensis, causing spores to dislodge at lower flow-induced shear forces, but had no effect on the attachment strength of P. robusta. Results are consistent with our prediction that reduced pH disrupts proper curing and gel formation of spore adhesives (anionic polysaccharides and glycoproteins) via protonation and cation displacement, although experimental verification is needed. Our results demonstrate that ocean acidification negatively, and differentially, impacts spore adhesion in two macroalgae. If results hold in field conditions, reduced ocean pH has the potential to impact macroalgal communities via spore dysfunction, regardless of the physiological tolerance of mature thalli. © 2017 Phycological Society of America.

  14. Live-imaging of Bacillus subtilis spore germination and outgrowth

    NARCIS (Netherlands)

    Pandey, R.

    2014-01-01

    Spores of Gram-positive bacteria such as Bacillus and Clostridium cause huge economic losses to the food industry. In food products, spores survive under food preservation conditions and subsequent germination and outgrowth eventually causes food spoilage. Therefore efforts are being made to

  15. Inactivation of Bacillus Anthracis Spores Using Carbon Nanotubes

    Science.gov (United States)

    2014-10-30

    effect of SWNTs in combination with antimicrobial chemicals on inactivation of B. anthracis spores; 4) the effect of CNTs coated surfaces on the...2010 31-May-2014 Approved for Public Release; Distribution Unlimited Final Report: (Life Science Division/ Biochemistry ) Inactivation of Bacillus... Biochemistry ) Inactivation of Bacillus Anthracis Spores Using Carbon Nanotubes Report Title The Specific Aims of the project were to investigate: 1) the

  16. Breaking the spores of Ganoderma lucidum by fermentation with ...

    African Journals Online (AJOL)

    In this paper, fermentation of G. lucidum with Lactobacillus plantarum was applied to break down the sporoderm. Scanning electron microscope (SEM) was used to characterize the spores. The broken spores were found on the 3rd day and complete breaking on the 5th day of fermentation. Lactic acid, acetic acid and ...

  17. Presence survival spores of Bacillus thuringiensis varieties in grain warehouse

    Directory of Open Access Journals (Sweden)

    Sánchez-Yáñez Juan Manuel

    2016-08-01

    Full Text Available Genus Bacillus thuringiensis (Bt synthesized spores and crystals toxic to pest-insects in agriculture. Bt is comospolitan then possible to isolate some subspecies or varieties from warehouse. The aims of study were: i to isolate Bt varieties from grain at werehouse ii to evaluate Bt toxicity on Spodoptera frugiperda and Shit-ophilus zeamaisese iii to analyze Bt spores persistence in Zea mays grains at werehouse compared to same Bt on grains exposed to sun radiation. Results showed that at werehouse were recovered more than one variety of Bt spores. According to each isolate Bt1 o Bt2 were toxic to S. frugiperda or S. zeamaisese. One those Bt belong to var morrisoni. At werehouse these spores on Z. mays grains surviving more time, while the same spores exposed to boicide sun radiation they died.

  18. Seasonal Trends in Airborne Fungal Spores in Coastal California Ecosystems

    Science.gov (United States)

    Morfin, J.; Crandall, S. G.; Gilbert, G. S.

    2014-12-01

    Airborne fungal spores cause disease in plants and animals and may trigger respiratory illnesses in humans. In terrestrial systems, fungal sporulation, germination, and persistence are strongly regulated by local meteorological conditions. However, few studies investigate how microclimate affects the spatio-temporal dynamics of airborne spores. We measured fungal aerospora abundance and microclimate at varying spatial and time scales in coastal California in three habitat-types: coast redwood forest, mixed-evergreen forest, and maritime chaparral. We asked: 1) is there a difference in total airborne spore concentration between habitats, 2) when do we see peak spore counts, and 3) do spore densities correlate with microclimate conditions? Fungal spores were caught from the air with a volumetric vacuum air spore trap during the wet season (January - March) in 2013 and 2014, as well as monthly in 2014. Initial results suggest that mixed-evergreen forests exhibit the highest amounts of spore abundance in both years compared to the other habitats. This may be due to either a higher diversity of host plants in mixed-evergreen forests or a rich leaf litter layer that may harbor a greater abundance of saprotrophic fungi. Based on pilot data, we predict that temperature and to a lesser degree, relative humidity, will be important microclimate predictors for high spore densities. These data are important for understanding when and under what weather conditions we can expect to see high levels of fungal spores in the air; this can be useful information for managers who are interested in treating diseased plants with fungicides.

  19. Decontamination Options for Drinking Water Contaminated with Bacillus anthracis Spores

    Energy Technology Data Exchange (ETDEWEB)

    Raber, E; Burklund, A

    2010-02-16

    Five parameters were evaluated with surrogates of Bacillus anthracis spores to determine effective decontamination options for use in a contaminated drinking water supply. The parameters were: (1) type of Bacillus spore surrogate (B. thuringiensis or B. atrophaeus); (2) spore concentration in suspension (10{sup 2} to 10{sup 6} spores/ml); (3) chemical characteristics of decontaminant [sodium dicholor-s-triazinetrione dihydrate (Dichlor), hydrogen peroxide, potassium peroxymonosulfate (Oxone), sodium hypochlorite, and VirkonS{reg_sign}]; (4) decontaminant concentration (0.01% to 5%); and (5) decontaminant exposure time (10 min to 24 hr). Results from 162 suspension tests with appropriate controls are reported. Hydrogen peroxide at a concentration of 5%, and Dichlor and sodium hypochlorite at a concentration of 2%, were effective at spore inactivation regardless of spore type tested, spore exposure time, or spore concentration evaluated. This is the first reported study of Dichlor as an effective decontaminant for B. anthracis spore surrogates. Dichlor's desirable characteristics of high oxidation potential, high level of free chlorine, and more neutral pH than that of other oxidizers evaluated appear to make it an excellent alternative. All three oxidizers were effective against B. atrophaeus spores in meeting EPA's biocide standard of greater than a 6 log kill after a 10-minute exposure time and at lower concentrations than typically reported for biocide use. Solutions of 5% VirkonS{reg_sign} and Oxone were less effective decontaminants than other options evaluated in this study and did not meet the EPA's efficacy standard for biocides. Differences in methods and procedures reported by other investigators make quantitative comparisons among studies difficult.

  20. Temperature-sensitive optrode

    Science.gov (United States)

    Hirschfeld, T.B.

    1985-09-24

    Method and apparatus are provided for measuring temperature and for generating optical signals related to temperature. Light from a fiber optic is directed to a material whose fluorescent response varies with ambient temperature. The same fiber optic delivering the excitation beam also collects a portion of the fluorescent emission for analysis. Signal collection efficiency of the fiber optic is enhanced by requiring that the fluorescent probe material be in the shape of an oblong parabolically tapered solid. Reproducibility is enhanced by using Raman backscatter to monitor excitation beam fluctuations, and by using measurements of fluorescence lifetime. 10 figs.

  1. [Temperature sensitivity of soil organic carbon mineralization and β-glucosidase enzymekinetics in the northern temperate forests at different altitudes, China].

    Science.gov (United States)

    Fan, Jin-juan; Li, Dan-dan; Zhang, Xin-yu; He, Nian-peng; Bu, Jin-feng; Wang, Qing; Sun, Xiao-min; Wen, Xue-fa

    2016-01-01

    Soil samples, which were collected from three typical forests, i.e., Betula ermanii forest, coniferous mixed broad-leaved forest, and Pinus koraiensis forest, at different altitudes along the southern slope of Laotuding Mountain of Changbai Mountain range in Liaoning Province of China, were incubated over a temperature gradient in laboratory. Soil organic carbon mineralization rates (Cmin), soil β-1,4-glucosidase (βG) kinetics and their temperature sensitivity (Q₁₀) were measured. The results showed that both altitude and temperature had significant effects on Cmin · Cmin increased with temperature and was highest in the B. ermanii forest. The temperature sensitivity of Cmin [Q₁₀(Cmin)] ranked in order of B. ermanii forest > P. koraiensis forest > coniferous mixed broad-leaved forest, but did not differ significantly among the three forests. Both the maximum activity (Vmax) and the Michaelis constant (Km) of the βG responded positively to temperature for all the forests. The temperature sensitivity of Vmax [Q₁₀(Vmax)] ranged from 1.78 to 1.90, and the temperature sensitivity of Km [Q₁₀(Km)] ranged from 1.79 to 2.00. The Q₁₀(Vmax)/Q10(Km) ratios were significantly greater in the B. ermanii soil than in the other two forest soils, suggesting that the βG kinetics-dependent impacts of the global warming or temperature increase on the decomposition of soil organic carbon were temperature sensitive for the forests at the higher altitudes.

  2. Fine mapping and characterization of Sr21, a temperature-sensitive diploid wheat resistance gene effective against the Puccinia graminis f. sp. tritici Ug99 race group.

    Science.gov (United States)

    Chen, Shisheng; Rouse, Matthew N; Zhang, Wenjun; Jin, Yue; Akhunov, Eduard; Wei, Yuming; Dubcovsky, Jorge

    2015-04-01

    The diploid wheat stem rust resistance gene Sr21 confers temperature-sensitive resistance to isolates of the Ug99 group and maps to the middle of the long arm of chromosome 2A (m). A race of Puccinia graminis f. sp. tritici, the causal pathogen of stem rust of wheat, known as Ug99, and its variants, are virulent to plants carrying stem rust resistance genes currently deployed in most wheat cultivars worldwide. Therefore, identification, mapping and deployment of effective resistance genes are critical to reduce this threat. Resistance gene Sr21 identified in diploid wheat T. monococcum can be effective against races from the Ug99 race group, but both susceptible and partial resistant reactions have been reported in previous studies. To clarify this conflicting information we screened four monogenic lines with Sr21 and four susceptible controls with 16 Pgt isolates including five isolates of the Ug99 race group under three different temperatures and three different photoperiods. We observed that, temperature influences the interaction between monogenic lines with Sr21 and Ug99 race group isolates, and may be one source of previous inconsistencies. This result indicates that, although Sr21 confers partial resistance against Ug99, its effectiveness can be modulated by environmental conditions and should not be deployed alone. Using two large diploid wheat-mapping populations (total 3,788 F2 plants) we mapped Sr21 approximately 50 cM from the centromere on the long arm of chromosome 2A(m) within a 0.20 cM interval flanked by sequence-based markers FD527726 and EX594406. The closely linked markers identified in this study will be useful to reduce the T. monococcum segments introgressed into common wheat, accelerate Sr21 deployment in wheat breeding programs, and facilitate the map-based cloning of this gene.

  3. Effect of Low-Temperature Sensitization on the Corrosion Behavior of AISI Type 304L SS Weld Metal in Simulated Groundwater

    Science.gov (United States)

    Suresh, Girija; Nandakumar, T.; Viswanath, A.

    2018-04-01

    The manuscript presents the investigations carried out on the effect of low-temperature sensitization (LTS) of 304L SS weld metal on its corrosion behavior in simulated groundwater, for its application as a canister material for long-term storage of nuclear vitrified high-level waste in geological repositories. AISI type 304L SS weld pad was fabricated by multipass gas tungsten arc welding process using 308L SS filler wire. The as-welded specimens were subsequently subjected to carbide nucleation and further to LTS at 500 °C for 11 days to simulate a temperature of 300 °C for 100-year life of the canister in geological repositories. Delta ferrite (δ-ferrite) content of the 304L SS weld metal substantially decreased on carbide nucleation treatment and further only a marginal decrease occurred on LTS treatment. The microstructure of the as-welded consisted of δ-ferrite as a minor phase distributed in austenite matrix. The δ-ferrite appeared fragmented in the carbide-nucleated and LTS-treated weld metal. The degree of sensitization measured by double-loop electrochemical potentokinetic reactivation method indicated an increase in carbide nucleation treatment when compared to the as-welded specimens, and further increase occurred on LTS treatment. Potentiodynamic anodic polarization investigations in simulated groundwater indicated a substantial decrease in the localized corrosion resistance of the carbide-nucleated and LTS 304L SS weld metals, when compared to the as-welded specimens. Post-experimental micrographs indicated pitting as the primary mode of attack in the as-welded, while pitting and intergranular corrosion (IGC) occurred in the carbide-nucleated weld metal. LTS-treated weld metal predominantly underwent IGC attack. The decrease in the localized corrosion resistance of the weld metal after LTS treatment was found to have a direct correlation with the degree of sensitization and the weld microstructure. The results are detailed in the manuscript.

  4. Germination Requirements of Bacillus macerans Spores

    Science.gov (United States)

    Sacks, L. E.; Thompson, P. A.

    1971-01-01

    2-Phenylacetamide is an effective germinant for spores of five strains of Bacillus macerans, particularly in the presence of fructose. Benzyl penicillin, the phenyl acetamide derivative of penicillin, and phenylacetic acid are also good germinants. l-Asparagine is an excellent germinant for four strains. α-Amino-butyric acid is moderately effective. Pyridoxine, pyridoxal, adenine, and 2,6-diaminopurine are potent germinants for NCA strain 7X1 only. d-Glucose is a powerful germinant for strain B-70 only. d-Fructose and d-ribose strongly potentiate germination induced by other germinants (except l-asparagine) but have only weak activity by themselves. Niacinamide and nicotinamide-adenine dinucleotide, inactive by themselves, are active in the presence of fructose or ribose. Effects of pH, ion concentration, and temperature are described. PMID:4251279

  5. Low temperature sensitization behavior in the weld metal of austenitic stainless steel. Study on low temperature sensitization in weldments of austenitic stainless steels and its improvement by laser surface melting treatment. 1

    International Nuclear Information System (INIS)

    Mori, Hiroaki; Nishimoto, Kazutoshi; Nakao, Yoshikuni

    1996-01-01

    Low temperature sensitization (LTS) behavior in the weld metal of Type308 stainless steel was investigated in this study. Three kinds of Type308 stainless steels, of which carbon contents were 0.04%, 0.06% and 0.08%, were used for this study. TIG welding method was adopted to make the weld metals. Weld metals were subjected to the sensitizing heat treatment in the temperature range between 773 K and 1073 K. The degree of sensitization were examined by the EPR method and the Strauss test. Chromium carbide was absorbed to precipitate at δ/γ grain boundaries in the as-welded weld metals Corrosion test results have shown that the higher carbon content in the weld metal is, the earlier sensitization yields in it. Sensitization in weld metals is found to occur faster than in those solution heat-treated at 1273 K prior to sensitizing heat-treatment. This fact suggests that preexisted chromium carbides have an effect to accelerate sensitization. That is, it is apparent that LTS phenomenon occur even in the weld metal. Moreover, sensitization in the weld metal has occurred in much shorter time than in HAZ, which is attributed to the preferential precipitation of chromium carbide at δ/γ grain boundaries in the weld metals. (author)

  6. Using Spores for Fusarium spp. Classification by MALDI-Based Intact Cell/Spore Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Wolfgang Winkler

    2012-01-01

    Full Text Available Fusarium is a widespread genus of filamentous fungi and a member of the soil microbial community. Certain subspecies are health threatening because of their mycotoxin production that affects the human and animal food chain. Thus, for early and effective pest control, species identification is of particular interest; however, differentiation on the subspecies level is challenging and time-consuming for this fungus. In the present study, we show the possibilities of intact cell mass spectrometry for spore analysis of 22 different Fusarium strains belonging to six Fusarium subspecies. We found that species differentiation is possible if mass spectrometric analyses are performed under well-defined conditions with fixed parameters. A critical point for analysis is a proper sample preparation of spores, which increases the quality of mass spectra with respect to signal intensity and m/z value variations. It was concluded that data acquistion has to be performed automatically; otherwise, user-specific variations are introduced generating data which cannot fit the existing datasets. Data that show clearly that matrix-assisted laser desorption ionization-based intact cell/intact spore mass spectrometry (IC/ISMS can be applied to differentiate closely related Fusarium spp. are presented. Results show a potential to build a database on Fusarium species for accurate species identification, for fast response in the case of infections in the cornfield. We furthermore demonstrate the high precision of our approach in classification of intact Fusarium species according to the location of their collection.

  7. Effects of different tree species on soil organic matter composition, decomposition rates and temperature sensitivities in boreal forest

    Science.gov (United States)

    Segura, Javier; Nilsson, Mats B.; Erhagen, Björn; Sparrman, Tobias; Ilstedt, Ulrik; Schleucher, Jürgen; Öquist, Mats

    2017-04-01

    High-latitude ecosystems store a large proportion of the global soil organic matter (SOM) and its mineralization constitutes a major carbon flux to the atmosphere. It has been suggested that different tree species can significantly influence organo-chemical composition of SOM, and rate and temperature sensitivity of SOM decomposition. In this study we used surface soil samples (top 5 cm) from a field experiment where five different tree species (Pinus silvestrys L, Picea abies (L.) H. Karst., Larix decidua Mill., Betula pendula Roth, and Pinus contorta Douglas) were planted on a grass meadow in a randomized block design (n=3) ca. 40 years ago. The samples were incubated at 4, 9, 14, and 19 °C at a soil water potential of -25 kPa (previously determined as optimal water content for decomposition). CO2 production rates were measured hourly for 13 days. CO2 production rates were consequently lowest in the control plots and increased in the order Meadow< Contorta < Betula < Larix < Pinus < Picea. The values ranged between 0.03-0.1, 0.06-0.154, 0.1-0.24 and 0.13-0.36 mg CO2 g-1 OM (dw) h-1 at 4, 9, 14 and 19°C respectively. The temperature response of CO2 production corresponded to Q10s of 2.22 (±0.11), 2.22(±0.15), 2.66 (±0.18), 2.09 (±0.33), 2.38 (±0.31) and 2.31 (±0.09) for meadow, contorta, betula, larix, pinus and picea respectively. Only betula resulted in significantly higher Q10s as compared to the control plots, picea, contorta and larix treatments. These differences in tree species effects on SOM decomposition and its temperature sensitivity will be further discussed in relation to the organo-chemical composition of SOM as determined by pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) and nuclear magnetic resonance spectroscopy (NMR) techniques. We conclude that the temperature response of SOM decomposition rates is likely coupled to tree species composition and may have important implications for soil C dynamics. This finding can have

  8. Dynamic phase microscopy, a new method to detect viable and killed spores and to estimate the heterogeneity of spore populations

    Science.gov (United States)

    Tychinsky, Vladimir P.; Mulyukin, Andrey L.; Lisovskii, Vitalii V.; Nikolaev, Yury A.; Kretushev, Aleksander V.; Vyshenskaya, Tatyana V.; Suzina, Nataliya E.; Duda, Vitalii I.; El-Registan, Galina I.

    One of the challenging tasks in monitoring studies is to estimate heterogeneity of microbial populations by the physiological state and potential viability of individual cells, especially with regard of their ability to withstand various environmental assaults. Previously, we described some approaches based on electron microscopy methods to discriminate vegetative, dormant, and dead cells in both aged microbial cultures and environmental samples, including permafrost. We propose to extend the arsenal of microscopy methods for monitoring studies by a new non-invasive and informative method - dynamic phase microscopy (DPM). The substantial advantage of DPM is that it gives quantitative (digitized) data of undestroyed (living) microscopic objects, exemplified in our work by Bacillus licheniformis spores. Using DPM made it possible to record interference images of objects (spores) and to produce picture of their "phase thickness" (PT) that is the optical path difference in nm. Thus, it was demonstrated the remarkable difference in the PT of spores at different physiological states: dormant, germinating, and heat-killed spores had PT values of 80, 40-50, and 20 nm, respectively. The other found criterion to distinguish between spores was the PT fluctuations. In contrast to dormant and killed spores, the PT of germinating spores oscillated with amplitude of up to 7 nm, with typical frequencies of 1.3 and 3.4 Hz. A combination of the recorded PT values and PT fluctuations gave a key to detect viable and dead cells. Under the conditions that did not support germination (the lack of nutrients), we were able to follow the response of a single dormant spore and a spore population to heating from 25 °C to 70 °C. Thus, a very small temperature change (from 40 °C to 42 °C) under conditions non-favorable for germination, caused a drastic decrease in the spores' PT; the second drop in the PT values was observed during heating from 60 °C to 70 °C. These changes were

  9. Water Behavior in Bacterial Spores by Deuterium NMR Spectroscopy

    Science.gov (United States)

    2015-01-01

    Dormant bacterial spores are able to survive long periods of time without nutrients, withstand harsh environmental conditions, and germinate into metabolically active bacteria when conditions are favorable. Numerous factors influence this hardiness, including the spore structure and the presence of compounds to protect DNA from damage. It is known that the water content of the spore core plays a role in resistance to degradation, but the exact state of water inside the core is a subject of discussion. Two main theories present themselves: either the water in the spore core is mostly immobile and the core and its components are in a glassy state, or the core is a gel with mobile water around components which themselves have limited mobility. Using deuterium solid-state NMR experiments, we examine the nature of the water in the spore core. Our data show the presence of unbound water, bound water, and deuterated biomolecules that also contain labile deuterons. Deuterium–hydrogen exchange experiments show that most of these deuterons are inaccessible by external water. We believe that these unreachable deuterons are in a chemical bonding state that prevents exchange. Variable-temperature NMR results suggest that the spore core is more rigid than would be expected for a gel-like state. However, our rigid core interpretation may only apply to dried spores whereas a gel core may exist in aqueous suspension. Nonetheless, the gel core, if present, is inaccessible to external water. PMID:24950158

  10. Water behavior in bacterial spores by deuterium NMR spectroscopy.

    Science.gov (United States)

    Friedline, Anthony W; Zachariah, Malcolm M; Johnson, Karen; Thomas, Kieth J; Middaugh, Amy N; Garimella, Ravindranath; Powell, Douglas R; Vaishampayan, Parag A; Rice, Charles V

    2014-07-31

    Dormant bacterial spores are able to survive long periods of time without nutrients, withstand harsh environmental conditions, and germinate into metabolically active bacteria when conditions are favorable. Numerous factors influence this hardiness, including the spore structure and the presence of compounds to protect DNA from damage. It is known that the water content of the spore core plays a role in resistance to degradation, but the exact state of water inside the core is a subject of discussion. Two main theories present themselves: either the water in the spore core is mostly immobile and the core and its components are in a glassy state, or the core is a gel with mobile water around components which themselves have limited mobility. Using deuterium solid-state NMR experiments, we examine the nature of the water in the spore core. Our data show the presence of unbound water, bound water, and deuterated biomolecules that also contain labile deuterons. Deuterium-hydrogen exchange experiments show that most of these deuterons are inaccessible by external water. We believe that these unreachable deuterons are in a chemical bonding state that prevents exchange. Variable-temperature NMR results suggest that the spore core is more rigid than would be expected for a gel-like state. However, our rigid core interpretation may only apply to dried spores whereas a gel core may exist in aqueous suspension. Nonetheless, the gel core, if present, is inaccessible to external water.

  11. Infrared signatures to discriminate viability of autoclaved Bacillus spores

    Science.gov (United States)

    Schneider, Matthew D. W.; Valentine, Nancy B.; Johnson, Timothy J.

    2011-11-01

    Optical methods can offer good sensitivity for detecting small amounts of chemicals and biologicals, and as these methods mature, are some of the few techniques that can offer true standoff detection. For detection of biological species, determining the viability is clearly important: Certain species of gram-positive bacteria are capable of forming endospores, specialized structures that arise when living conditions become unfavorable or little growth medium is available. Spores are also resistant to many chemicals as well as changes in heat or pH; such spores can remain dormant from months to years until more favorable conditions arise, resulting in germination back to the vegetative state. This persistence characteristic of bacterial spores allows for contamination of a surface (e.g. food or medical equipment) even after the surface has been nominally cleaned. Bacterial spores have also been used as biological weapons, as in the case of B. anthracis. Thus, having rapid analytical methods to determine a spore's viability after attempts to clean a given environment is crucial. The increasing availability of portable spectrometers may provide a key to such rapid onsite analysis. The present study was designed to determine whether infrared spectroscopy may be used to differentiate between viable vs. dead B. subtilis and B. atrophaeus spores. Preliminary results show that the reproducible differences in the IR signatures can be used to identify the viable vs. the autoclaved (dead) spores.

  12. Effect of Essential Oils on Germination and Growth of Some Pathogenic and Spoilage Spore-Forming Bacteria.

    Science.gov (United States)

    Voundi, Stève Olugu; Nyegue, Maximilienne; Lazar, Iuliana; Raducanu, Dumitra; Ndoye, Florentine Foe; Marius, Stamate; Etoa, François-Xavier

    2015-06-01

    The use of essential oils as a food preservative has increased due to their capacity to inhibit vegetative growth of some bacteria. However, only limited data are available on their effect on bacterial spores. The aim of the present study was to evaluate the effect of some essential oils on the growth and germination of three Bacillus species and Geobacillus stearothermophilus. Essential oils were chemically analyzed using gas chromatography and gas chromatography coupled to mass spectrometry. The minimal inhibitory and bactericidal concentrations of vegetative growth and spore germination were assessed using the macrodilution method. Germination inhibitory effect of treated spores with essential oils was evaluated on solid medium, while kinetic growth was followed using spectrophotometry in the presence of essential oils. Essential oil from Drypetes gossweileri mainly composed of benzyl isothiocyanate (86.7%) was the most potent, with minimal inhibitory concentrations ranging from 0.0048 to 0.0097 mg/mL on vegetative cells and 0.001 to 0.002 mg/mL on spore germination. Furthermore, essential oil from D. gossweileri reduced 50% of spore germination after treatment at 1.25 mg/mL, and its combination with other oils improved both bacteriostatic and bactericidal activities with additive or synergistic effects. Concerning the other essential oils, the minimal inhibitory concentration ranged from 5 to 0.63 mg/mL on vegetative growth and from 0.75 to 0.09 mg/mL on the germination of spores. Spectrophotometric evaluation showed an inhibitory effect of essential oils on both germination and outgrowth. From these results, it is concluded that some of the essential oils tested might be a valuable tool for bacteriological control in food industries. Therefore, further research regarding their use as food preservatives should be carried out.

  13. Antitumor effects and mechanisms of Ganoderma extracts and spores oil

    Science.gov (United States)

    Chen, Chun; Li, Peng; Li, Ye; Yao, Guan; Xu, Jian-Hua

    2016-01-01

    Ganoderma lucidum is a popular herbal medicine used in China to promote health. Modern studies have disclosed that the active ingredients of Ganoderma can exhibit several effects, including antitumor effects and immunomodulation. The present study evaluated the antitumor effects of self-prepared Ganoderma extracts and spores oil, and investigated the possible underlying mechanisms by observing the effects of the extracts and oil on topoisomerases and the cell cycle. The results showed that Ganoderma extracts and spores oil presented dose-dependent inhibitory effects on tumor cells. The half maximal inhibitory concentration (IC50) values of Ganoderma extracts on HL60, K562 and SGC-7901 cells for 24 h were 0.44, 0.39 and 0.90 mg/ml, respectively; for Ganoderma spores oil, the IC50 values were 1.13, 2.27 and 6.29 mg/ml, respectively. In the in vivo study, the inhibitory rates of Ganoderma extracts (4 g/kg/d, intragastrically) on S180 and H22 cells were 39.1 and 44.6%, respectively, and for Ganoderma spores oil (1.2 g/kg/d, intragastrically) the inhibitory rates were 30.9 and 44.9%, respectively. Ganoderma extracts and spores oil inhibited the activities of topoisomerase I and II. Ganoderma spores oil was shown block the cell cycle at the transition between the G1 and S phases and induce a marked decrease in cyclin D1 levels in K562 cells, with no significant change in cyclin E level. These results suggest that the Ganoderma extracts and spores oil possessed antitumor effects in the in vitro and in vivo studies. The antitumor mechanisms of the extracts and spores oil were associated with inhibitory effects on topoisomerase I and II activities, and for Ganoderma spores oil, the antitumor effects may also be associated with decreased cyclin D1 levels, thus inducing G1 arrest in the cell cycle. PMID:27900038

  14. Bacteriocins: Novel Solutions to Age Old Spore-Related Problems?

    Directory of Open Access Journals (Sweden)

    Kevin eEgan

    2016-04-01

    Full Text Available Bacteriocins are ribosomally synthesized antimicrobial peptides produced by bacteria, which have the ability to kill or inhibit other bacteria. Many bacteriocins are produced by food grade lactic acid bacteria (LAB. Indeed, the prototypic bacteriocin, nisin, is produced by Lactococcus lactis, and is licensed in over 50 countries. With consumers becoming more concerned about the levels of chemical preservatives present in food, bacteriocins offer an alternative, more natural, approach, while ensuring both food safety and product shelf life. Bacteriocins also show additive/synergistic effects when used in combination with other treatments, such as heating, high pressure, organic compounds, and as part of food packaging. These features are particularly attractive from the perspective of controlling sporeforming bacteria. Bacterial spores are common contaminants of food products, and their outgrowth may cause food spoilage or food-borne illness. They are of particular concern to the food industry due to their thermal and chemical resistance in their dormant state. However, when spores germinate they lose the majority of their resistance traits, making them susceptible to a variety of food processing treatments. Bacteriocins represent one potential treatment as they may inhibit spores in the post-germination/outgrowth phase of the spore cycle. Spore eradication and control in food is critical, as they are able to spoil and in certain cases compromise the safety of food by producing dangerous toxins. Thus, understanding the mechanisms by which bacteriocins exert their sporostatic/sporicidal activity against bacterial spores will ultimately facilitate their optimal use in food. This review will focus on the use of bacteriocins alone, or in combination with other innovative processing methods to control spores in food, the current knowledge and gaps therein with regard to bacteriocin-spore interactions and discuss future research approaches to enable

  15. Sterilization Resistance of Bacterial Spores Explained with Water Chemistry.

    Science.gov (United States)

    Friedline, Anthony W; Zachariah, Malcolm M; Middaugh, Amy N; Garimella, Ravindranath; Vaishampayan, Parag A; Rice, Charles V

    2015-11-05

    Bacterial spores can survive for long periods without nutrients and in harsh environmental conditions. This survival is influenced by the structure of the spore, the presence of protective compounds, and water retention. These compounds, and the physical state of water in particular, allow some species of bacterial spores to survive sterilization schemes with hydrogen peroxide and UV light. The chemical nature of the spore core and its water has been a subject of some contention and the chemical environment of the water impacts resistance paradigms. Either the spore has a glassy core, where water is immobilized along with other core components, or the core is gel-like with mobile water diffusion. These properties affect the movement of peroxide and radical species, and hence resistance. Deuterium solid-state NMR experiments are useful for examining the nature of the water inside the spore. Previous work in our lab with spores of Bacillus subtilis indicate that, for spores, the core water is in a more immobilized state than expected for the gel-like core theory, suggesting a glassy core environment. Here, we report deuterium solid-state NMR observations of the water within UV- and peroxide-resistant spores from Bacillus pumilus SAFR-032. Variable-temperature NMR experiments indicate no change in the line shape after heating to 50 °C, but an overall decrease in signal after heating to 100 °C. These results show glass-like core dynamics within B. pumilus SAFR-032 that may be the potential source of its known UV-resistance properties. The observed NMR traits can be attributed to the presence of an exosporium containing additional labile deuterons that can aid in the deactivation of sterilizing agents.

  16. Bacteriocins: Novel Solutions to Age Old Spore-Related Problems?

    Science.gov (United States)

    Egan, Kevin; Field, Des; Rea, Mary C; Ross, R Paul; Hill, Colin; Cotter, Paul D

    2016-01-01

    Bacteriocins are ribosomally synthesized antimicrobial peptides produced by bacteria, which have the ability to kill or inhibit other bacteria. Many bacteriocins are produced by food grade lactic acid bacteria (LAB). Indeed, the prototypic bacteriocin, nisin, is produced by Lactococcus lactis, and is licensed in over 50 countries. With consumers becoming more concerned about the levels of chemical preservatives present in food, bacteriocins offer an alternative, more natural approach, while ensuring both food safety and product shelf life. Bacteriocins also show additive/synergistic effects when used in combination with other treatments, such as heating, high pressure, organic compounds, and as part of food packaging. These features are particularly attractive from the perspective of controlling sporeforming bacteria. Bacterial spores are common contaminants of food products, and their outgrowth may cause food spoilage or food-borne illness. They are of particular concern to the food industry due to their thermal and chemical resistance in their dormant state. However, when spores germinate they lose the majority of their resistance traits, making them susceptible to a variety of food processing treatments. Bacteriocins represent one potential treatment as they may inhibit spores in the post-germination/outgrowth phase of the spore cycle. Spore eradication and control in food is critical, as they are able to spoil and in certain cases compromise the safety of food by producing dangerous toxins. Thus, understanding the mechanisms by which bacteriocins exert their sporostatic/sporicidal activity against bacterial spores will ultimately facilitate their optimal use in food. This review will focus on the use of bacteriocins alone, or in combination with other innovative processing methods to control spores in food, the current knowledge and gaps therein with regard to bacteriocin-spore interactions and discuss future research approaches to enable spores to be more

  17. Bacteriocins: Novel Solutions to Age Old Spore-Related Problems?

    Science.gov (United States)

    Egan, Kevin; Field, Des; Rea, Mary C.; Ross, R. Paul; Hill, Colin; Cotter, Paul D.

    2016-01-01

    Bacteriocins are ribosomally synthesized antimicrobial peptides produced by bacteria, which have the ability to kill or inhibit other bacteria. Many bacteriocins are produced by food grade lactic acid bacteria (LAB). Indeed, the prototypic bacteriocin, nisin, is produced by Lactococcus lactis, and is licensed in over 50 countries. With consumers becoming more concerned about the levels of chemical preservatives present in food, bacteriocins offer an alternative, more natural approach, while ensuring both food safety and product shelf life. Bacteriocins also show additive/synergistic effects when used in combination with other treatments, such as heating, high pressure, organic compounds, and as part of food packaging. These features are particularly attractive from the perspective of controlling sporeforming bacteria. Bacterial spores are common contaminants of food products, and their outgrowth may cause food spoilage or food-borne illness. They are of particular concern to the food industry due to their thermal and chemical resistance in their dormant state. However, when spores germinate they lose the majority of their resistance traits, making them susceptible to a variety of food processing treatments. Bacteriocins represent one potential treatment as they may inhibit spores in the post-germination/outgrowth phase of the spore cycle. Spore eradication and control in food is critical, as they are able to spoil and in certain cases compromise the safety of food by producing dangerous toxins. Thus, understanding the mechanisms by which bacteriocins exert their sporostatic/sporicidal activity against bacterial spores will ultimately facilitate their optimal use in food. This review will focus on the use of bacteriocins alone, or in combination with other innovative processing methods to control spores in food, the current knowledge and gaps therein with regard to bacteriocin-spore interactions and discuss future research approaches to enable spores to be more

  18. Antitumor effects and mechanisms of Ganoderma extracts and spores oil.

    Science.gov (United States)

    Chen, Chun; Li, Peng; Li, Ye; Yao, Guan; Xu, Jian-Hua

    2016-11-01

    Ganoderma lucidum is a popular herbal medicine used in China to promote health. Modern studies have disclosed that the active ingredients of Ganoderma can exhibit several effects, including antitumor effects and immunomodulation. The present study evaluated the antitumor effects of self-prepared Ganoderma extracts and spores oil, and investigated the possible underlying mechanisms by observing the effects of the extracts and oil on topoisomerases and the cell cycle. The results showed that Ganoderma extracts and spores oil presented dose-dependent inhibitory effects on tumor cells. The half maximal inhibitory concentration (IC 50 ) values of Ganoderma extracts on HL60, K562 and SGC-7901 cells for 24 h were 0.44, 0.39 and 0.90 mg/ml, respectively; for Ganoderma spores oil, the IC 50 values were 1.13, 2.27 and 6.29 mg/ml, respectively. In the in vivo study, the inhibitory rates of Ganoderma extracts (4 g/kg/d, intragastrically) on S180 and H22 cells were 39.1 and 44.6%, respectively, and for Ganoderma spores oil (1.2 g/kg/d, intragastrically) the inhibitory rates were 30.9 and 44.9%, respectively. Ganoderma extracts and spores oil inhibited the activities of topoisomerase I and II. Ganoderma spores oil was shown block the cell cycle at the transition between the G1 and S phases and induce a marked decrease in cyclin D1 levels in K562 cells, with no significant change in cyclin E level. These results suggest that the Ganoderma extracts and spores oil possessed antitumor effects in the in vitro and in vivo studies. The antitumor mechanisms of the extracts and spores oil were associated with inhibitory effects on topoisomerase I and II activities, and for Ganoderma spores oil, the antitumor effects may also be associated with decreased cyclin D1 levels, thus inducing G1 arrest in the cell cycle.

  19. Study on the ice nucleation activity of fungal spores (Ascomycota and Basidiomycota)

    Science.gov (United States)

    Pummer, B. G.; Atanasova, L.; Bauer, H.; Bernardi, J.; Druzhinina, I. S.; Grothe, H.

    2012-04-01

    Biogenic ice nucleation (IN) in the atmosphere is a topic of growing interest, as, according to IPCC, the impact of IN on global climate is crucial to perform reliable climate model calculations. About 20 years ago IN activity of a few lichen and Fusarium species [1,2] was reported, while all other investigated fungi were IN-negative. However, as the fungal kingdom is vast, many abundant species, especially the Basidiomycota (most mushrooms), were not tested before. Furthermore, the focus of the past studies was on the IN activity of the mycelium as a cryoprotective mechanism, and not on the airborne spores. We carried out oil immersion measurements [3] with spores from 17 different fungal species of ecological, economical or sanitary importance. Most of these species have not been investigated before, like exponents of Aspergillus, Trichoderma and Agaricales (most mushrooms). Apart from F. avenaceum, spores of all measured species showed moderate or no IN activity, supporting the hypothesis that significant IN activity is a rather exclusive property of only a few species within the fungal kingdom. [1] Kieft TL and Ruscetti T: J. Bacteriol. 172, 3519-3523, 1990. [2] Pouleur S et al.: Appl. Environ. Microbiol., 58, 2960-2964, 1992. [3] Marcolli C et al.: Atmos. Chem. Phys. 7, 5081-5091, 2007.

  20. Reversible Hydrolysis Reaction with the Spore Photoproduct under Alkaline Conditions.

    Science.gov (United States)

    Adhikari, Surya; Lin, Gengjie; Li, Lei

    2016-09-16

    DNA lesions may reduce the electron density at the nucleobases, making them prone to further modifications upon the alkaline treatment. The dominant DNA photolesion found in UV-irradiated bacterial endospores is a thymine dimer, 5-thyminyl-5,6-dihydrothymine, i.e., the spore photoproduct (SP). Here we report a stepwise addition/elimination reaction in the SP hydrolysis product under strong basic conditions where a ureido group is added to the carboxyl moiety to form a cyclic amide, regenerating SP after eliminating a hydroxide ion. Direct amidation of carboxylic acids by reaction with amines in the presence of a catalyst is well documented; however, it is very rare for an amidation reaction to occur without activation. This uncatalyzed SP reverse reaction in aqueous solution is even more surprising because the carboxyl moiety is not a good electrophile due to the negative charge it carries. Examination of the base-catalyzed hydrolyses of two other saturated pyrimidine lesions, 5,6-dihydro-2'-deoxyuridine and pyrimidine (6-4) pyrimidone photoproduct, reveals that neither reaction is reversible even though all three hydrolysis reactions may share the same gem-diol intermediate. Therefore, the SP structure where the two thymine residues maintain a stacked conformation likely provides the needed framework enabling this highly unusual carboxyl addition/elimination reaction.

  1. Boundary-Layer Detection at Cryogenic Conditions Using Temperature Sensitive Paint Coupled with a Carbon Nanotube Heating Layer

    Directory of Open Access Journals (Sweden)

    Kyle Z. Goodman

    2016-12-01

    Full Text Available Detection of flow transition on aircraft surfaces and models can be vital to the development of future vehicles and computational methods for evaluating vehicle concepts. In testing at ambient conditions, IR thermography is ideal for this measurement. However, for higher Reynolds number testing, cryogenic facilities are often used, in which IR thermography is difficult to employ. In these facilities, temperature sensitive paint is an alternative with a temperature step introduced to enhance the natural temperature change from transition. Traditional methods for inducing the temperature step by changing the liquid nitrogen injection rate often change the tunnel conditions. Recent work has shown that adding a layer consisting of carbon nanotubes to the surface can be used to impart a temperature step on the model surface with little change in the operating conditions. Unfortunately, this system physically degraded at 130 K and lost heating capability. This paper describes a modification of this technique enabling operation down to at least 77 K, well below the temperature reached in cryogenic facilities. This is possible because the CNT layer is in a polyurethane binder. This was tested on a Natural Laminar Flow model in a cryogenic facility and transition detection was successfully visualized at conditions from 200 K to 110 K. Results were also compared with the traditional temperature step method.

  2. Assignment of simian rotavirus SA11 temperature-sensitive mutant groups B and E to genome segments

    Energy Technology Data Exchange (ETDEWEB)

    Gombold, J.L.; Estes, M.K.; Ramig, R.F.

    1985-05-01

    Recombinant (reassortant) viruses were selected from crosses between temperature-sensitive (ts) mutants of simian rotavirus SA11 and wild-type human rotavirus Wa. The double-stranded genome RNAs of the reassortants were examined by electrophoresis in Tris-glycine-buffered polyacrylamide gels and by dot hybridization with a cloned DNA probe for genome segment 2. Analysis of replacements of genome segments in the reassortants allowed construction of a map correlating genome segments providing functions interchangeable between SA11 and Wa. The reassortants revealed a functional correspondence in order of increasing electrophoretic mobility of genome segments. Analysis of the parental origin of genome segments in ts+ SA11/Wa reassortants derived from the crosses SA11 tsB(339) X Wa and SA11 tsE(1400) X Wa revealed that the group B lesion of tsB(339) was located on genome segment 3 and the group E lesion of tsE(1400) was on segment 8.

  3. Boundary-Layer Detection at Cryogenic Conditions Using Temperature Sensitive Paint Coupled with a Carbon Nanotube Heating Layer

    Science.gov (United States)

    Goodman, Kyle Z.; Lipford, William E.; Watkins, Anthony Neal

    2016-01-01

    Detection of flow transition on aircraft surfaces and models can be vital to the development of future vehicles and computational methods for evaluating vehicle concepts. In testing at ambient conditions, IR thermography is ideal for this measurement. However, for higher Reynolds number testing, cryogenic facilities are often used, in which IR thermography is difficult to employ. In these facilities, temperature sensitive paint is an alternative with a temperature step introduced to enhance the natural temperature change from transition. Traditional methods for inducing the temperature step by changing the liquid nitrogen injection rate often change the tunnel conditions. Recent work has shown that adding a layer consisting of carbon nanotubes to the surface can be used to impart a temperature step on the model surface with little change in the operating conditions. Unfortunately, this system physically degraded at 130 K and lost heating capability. This paper describes a modification of this technique enabling operation down to at least 77 K, well below the temperature reached in cryogenic facilities. This is possible because the CNT layer is in a polyurethane binder. This was tested on a Natural Laminar Flow model in a cryogenic facility and transition detection was successfully visualized at conditions from 200 K to 110 K. Results were also compared with the traditional temperature step method.

  4. Behavioural thermoregulation in a temperature-sensitive coral reef fish, the five-lined cardinalfish ( Cheilodipterus quinquelineatus)

    Science.gov (United States)

    Nay, Tiffany J.; Johansen, Jacob L.; Habary, Adam; Steffensen, John F.; Rummer, Jodie L.

    2015-12-01

    As global temperatures increase, fish populations at low latitudes are thought to be at risk as they are adapted to narrow temperature ranges and live at temperatures close to their thermal tolerance limits. Behavioural movements, based on a preference for a specific temperature ( T pref), may provide a strategy to cope with changing conditions. A temperature-sensitive coral reef cardinalfish ( Cheilodipterus quinquelineatus) was exposed to 28 °C (average at collection site) or 32 °C (predicted end-of-century) for 6 weeks. T pref was determined using a shuttlebox system, which allowed fish to behaviourally manipulate their thermal environment. Regardless of treatment temperature, fish preferred 29.5 ± 0.25 °C, approximating summer average temperatures in the wild. However, 32 °C fish moved more frequently to correct their thermal environment than 28 °C fish, and daytime movements were more frequent than night-time movements. Understanding temperature-mediated movements is imperative for predicting how ocean warming will influence coral reef species and distribution patterns.

  5. Temperature Sensitivity of Soil Respiration to Nitrogen Fertilization: Varying Effects between Growing and Non-Growing Seasons.

    Science.gov (United States)

    Liu, Qingfang; Wang, Rui; Li, Rujian; Hu, Yaxian; Guo, Shengli

    2016-01-01

    Nitrogen (N) fertilization has a considerable effect on food production and carbon cycling in agro-ecosystems. However, the impacts of N fertilization rates on the temperature sensitivity of soil respiration (Q10) were controversial. Five N rates (N0, N45, N90, N135, and N180) were applied to a continuous winter wheat (Triticum aestivum L.) crop on the semi-arid Loess Plateau, and the in situ soil respiration was monitored during five consecutive years from 2008 to 2013. During the growing season, the mean soil respiration rates increased with increasing N fertilization rates, peaking at 1.53 μmol m-2s-1 in the N135 treatment. A similar dynamic pattern was observed during the non-growing season, yet on average with 7.3% greater soil respiration rates than the growing season. In general for all the N fertilization treatments, the mean Q10 value during the non-growing season was significantly greater than that during the growing season. As N fertilization rates increased, the Q10 values did not change significantly in the growing season but significantly decreased in the non-growing season. Overall, N fertilization markedly influenced soil respirations and Q10 values, in particular posing distinct effects on the Q10 values between the growing and non-growing seasons.

  6. Temperature sensitivity and enzymatic mechanisms of soil organic matter decomposition along an altitudinal gradient on Mount Kilimanjaro.

    Science.gov (United States)

    Blagodatskaya, Еvgenia; Blagodatsky, Sergey; Khomyakov, Nikita; Myachina, Olga; Kuzyakov, Yakov

    2016-02-29

    Short-term acceleration of soil organic matter decomposition by increasing temperature conflicts with the thermal adaptation observed in long-term studies. Here we used the altitudinal gradient on Mt. Kilimanjaro to demonstrate the mechanisms of thermal adaptation of extra- and intracellular enzymes that hydrolyze cellulose, chitin and phytate and oxidize monomers ((14)C-glucose) in warm- and cold-climate soils. We revealed that no response of decomposition rate to temperature occurs because of a cancelling effect consisting in an increase in half-saturation constants (Km), which counteracts the increase in maximal reaction rates (Vmax with temperature). We used the parameters of enzyme kinetics to predict thresholds of substrate concentration (Scrit) below which decomposition rates will be insensitive to global warming. Increasing values of Scrit, and hence stronger canceling effects with increasing altitude on Mt. Kilimanjaro, explained the thermal adaptation of polymer decomposition. The reduction of the temperature sensitivity of Vmax along the altitudinal gradient contributed to thermal adaptation of both polymer and monomer degradation. Extrapolating the altitudinal gradient to the large-scale latitudinal gradient, these results show that the soils of cold climates with stronger and more frequent temperature variation are less sensitive to global warming than soils adapted to high temperatures.

  7. Screening a yeast library of temperature-sensitive mutants reveals a role for actin in tombusvirus RNA recombination.

    Science.gov (United States)

    Prasanth, K Reddisiva; Kovalev, Nikolay; de Castro Martín, Isabel Fernández; Baker, Jannine; Nagy, Peter D

    2016-02-01

    Genetic recombination in RNA viruses drives the evolutionary arms race with host's antiviral strategies and recombination also facilitates adaptation of viruses to new hosts. In this paper, the authors used tombusvirus and a temperature-sensitive (ts) mutant library of yeast to identify 40 host proteins affecting viral recombination in yeast model host. Subsequent detailed analysis with two identified actin-related proteins, Act1p and Arp3p, has revealed that the wt actin network helps TBSV to maintain low level viral recombination. Pharmacological inhibition of actin in plant protoplasts confirmed the role of the actin network in tombusvirus recombination. An in vitro approach revealed the altered activity of the tombusvirus replicase in the presence of mutated Act1p. The authors show more efficient recruitment of a cellular DEAD-box helicase, which enhances tombusvirus recombination, into the membrane-bound replicase in Act1p mutant yeast. Overall, this work shows that the actin network affects tombusvirus recombination in yeast and plant cells. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Changes in Temperature Sensitivity and Activation Energy of Soil Organic Matter Decomposition in Different Qinghai-Tibet Plateau Grasslands

    Science.gov (United States)

    Li, Jie; He, Nianpeng; Wei, Xuehong; Gao, Yang; Zuo, Yao

    2015-01-01

    Qinghai-Tibet Plateau grasslands are unique geographical regions and store substantial soil organic matter (SOM) in the soil surface, which make them very sensitive to global climate change. Here, we focused on three main grassland types (alpine meadow, steppe, and desert) and conducted a soil incubation experiment at five different temperatures (5, 10, 15, 20, and 25°C) to investigate SOM decomposition rates (R), temperature sensitivity (Q10), and activation energy (Ea). The results showed that grassland type and incubation temperature had significant impact on R (P alpinesteppe > alpine desert. The Q10 values differed significantly among different grasslands, and the overall trends were as follows: alpine meadow (1.56 ± 0.09) < alpine steppe (1.88 ± 0.23) < alpine desert (2.39 ± 0.32). Moreover, the Ea values differed significantly across different grassland types (P < 0.001) and increased with increasing incubation time. The exponential negative correlations between Ea and R at 20°C across all grassland types (all Ps < 0.001) indicated that the substrate-quality temperature hypothesis is applicable to the alpine grasslands. Our findings provide new insights for understanding the responses of SOM decomposition and storage to warming scenarios in this Plateau. PMID:26176705

  9. Assignment of simian rotavirus SA11 temperature-sensitive mutant groups B and E to genome segments

    International Nuclear Information System (INIS)

    Gombold, J.L.; Estes, M.K.; Ramig, R.F.

    1985-01-01

    Recombinant (reassortant) viruses were selected from crosses between temperature-sensitive (ts) mutants of simian rotavirus SA11 and wild-type human rotavirus Wa. The double-stranded genome RNAs of the reassortants were examined by electrophoresis in Tris-glycine-buffered polyacrylamide gels and by dot hybridization with a cloned DNA probe for genome segment 2. Analysis of replacements of genome segments in the reassortants allowed construction of a map correlating genome segments providing functions interchangeable between SA11 and Wa. The reassortants revealed a functional correspondence in order of increasing electrophoretic mobility of genome segments. Analysis of the parental origin of genome segments in ts+ SA11/Wa reassortants derived from the crosses SA11 tsB(339) X Wa and SA11 tsE(1400) X Wa revealed that the group B lesion of tsB(339) was located on genome segment 3 and the group E lesion of tsE(1400) was on segment 8

  10. Temperature sensitivity and enzymatic mechanisms of soil organic matter decomposition along an altitudinal gradient on Mount Kilimanjaro

    Science.gov (United States)

    Blagodatskaya, Еvgenia; Blagodatsky, Sergey; Khomyakov, Nikita; Myachina, Olga; Kuzyakov, Yakov

    2016-02-01

    Short-term acceleration of soil organic matter decomposition by increasing temperature conflicts with the thermal adaptation observed in long-term studies. Here we used the altitudinal gradient on Mt. Kilimanjaro to demonstrate the mechanisms of thermal adaptation of extra- and intracellular enzymes that hydrolyze cellulose, chitin and phytate and oxidize monomers (14C-glucose) in warm- and cold-climate soils. We revealed that no response of decomposition rate to temperature occurs because of a cancelling effect consisting in an increase in half-saturation constants (Km), which counteracts the increase in maximal reaction rates (Vmax with temperature). We used the parameters of enzyme kinetics to predict thresholds of substrate concentration (Scrit) below which decomposition rates will be insensitive to global warming. Increasing values of Scrit, and hence stronger canceling effects with increasing altitude on Mt. Kilimanjaro, explained the thermal adaptation of polymer decomposition. The reduction of the temperature sensitivity of Vmax along the altitudinal gradient contributed to thermal adaptation of both polymer and monomer degradation. Extrapolating the altitudinal gradient to the large-scale latitudinal gradient, these results show that the soils of cold climates with stronger and more frequent temperature variation are less sensitive to global warming than soils adapted to high temperatures.

  11. The defective phosphoribosyl diphosphate synthase in a temperature-sensitive prs-2 mutant of Escherichia coli is compensated by increased enzyme synthesis

    DEFF Research Database (Denmark)

    Post, David A.; Switzer, Robert L.; Hove-Jensen, Bjarne

    1996-01-01

    An Escherichia coli strain which is temperature-sensitive for growth due to a mutation (prs-2) causing a defective phosphoribosyl diphosphate (PRPP) synthase has been characterized. The temperature-sensitive mutation was mapped to a 276 bp HindIII-BssHII DNA fragment located within the open reading...... temperature shift to 42 degrees C. The other mutation was a C -> T transition located 39 bp upstream of the G -> A mutation, i.e. outside the coding sequence and close to the Shine-Dalgarno sequence. Cells harbouring only the C -> T mutation in a plasmid contained approximately three times as much PRPP...

  12. Characterization of small-spored Alternaria from Argentinean crops through a polyphasic approach.

    Science.gov (United States)

    da Cruz Cabral, Lucía; Rodriguero, Marcela; Stenglein, Sebastián; Fog Nielsen, Kristian; Patriarca, Andrea

    2017-09-18

    Small-spored Alternaria have been isolated from a wide variety of food crops, causing both economic losses and human health risk due to the metabolites produced. Their taxonomy has been discussed widely, but no scientific consensus has been established in this field to date. Argentina is a major exporter of agricultural products, so it is essential to thoroughly understand the physiological behaviour of this pathogen in a food safety context. Thus, the objective of this work was to characterize small-spored Alternaria spp. obtained from tomato fruits, pepper fruits, wheat grains and blueberries from Argentina by a polyphasic approach involving metabolomic and phylogenetic analyses based on molecular and morphological characters. Morphological analysis divided the population studied into three groups; A. arborescens sp.-grp., A. tenuissima sp.-grp., and A. alternata sp.-grp. However, when these characters were simultaneously analysed with molecular data, no clearly separated groups were obtained. Haplotype network and phylogenetic analysis (both Bayesian and maximum parsimony) of a conserved region yielded the same result, suggesting that all isolates belong to the same species. Furthermore, no correlation could be established between morphological species-groups and a metabolite or group of metabolites synthesized. Thus, the whole set of analyses carried out in the present work supports the hypothesis that these small-spored Alternaria isolates from food belong to the same species. Identification at species level through classical morphology or modern molecular techniques does not seem to be a useful tool to predict toxicological risk in food matrices. The detection of any small-spored Alternaria from Section Alternaria (D.P. Lawr., Gannibal, Peever & B.M. Pryor 2013) in food implies a potential toxicological risk. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Inactivation Strategies for Clostridium perfringens Spores and Vegetative Cells.

    Science.gov (United States)

    Talukdar, Prabhat K; Udompijitkul, Pathima; Hossain, Ashfaque; Sarker, Mahfuzur R

    2017-01-01

    Clostridium perfringens is an important pathogen to human and animals and causes a wide array of diseases, including histotoxic and gastrointestinal illnesses. C. perfringens spores are crucial in terms of the pathogenicity of this bacterium because they can survive in a dormant state in the environment and return to being live bacteria when they come in contact with nutrients in food or the human body. Although the strategies to inactivate C. perfringens vegetative cells are effective, the inactivation of C. perfringens spores is still a great challenge. A number of studies have been conducted in the past decade or so toward developing efficient inactivation strategies for C. perfringens spores and vegetative cells, which include physical approaches and the use of chemical preservatives and naturally derived antimicrobial agents. In this review, different inactivation strategies applied to control C. perfringens cells and spores are summarized, and the potential limitations and challenges of these strategies are discussed. Copyright © 2016 American Society for Microbiology.

  14. LEVELS AND TYPES OF AEROBIC SPORE FORMING BACTERIA ...

    African Journals Online (AJOL)

    Limnothrissa miodon) had the product sourced from them analysed morphologically by a microscope and biochemically for levels of aerobic spore forming bacteria that could adversely affect safety of the product. The four companies whose packaged ...

  15. Analysis of Bacillus Globigii Spores Using the BioDetector

    National Research Council Canada - National Science Library

    Lee, William

    1999-01-01

    .... An automated immunoassay instrument capable of providing rapid identification of biological agents was used to analyses laboratory and field trial samples containing the field trial simulants Bacillus globigii (BG) spores...

  16. Late Silurian trilete spores from northern Jiangsu, China.

    Science.gov (United States)

    Wang; Li

    2000-08-01

    The Late Silurian is generally considered to a particular significant key period in the study of early land vascular plants. A trilete spore assemblage of the Upper Silurian is described from northern Jiangsu, China. This assemblage comprises 11 genera and 20 species of trilete spores (including laevigate, apiculate, perinotrilite, patinate, rarely distally murornate and equatorially crassitate, and three indeterminate trilete miospores forms). It has similarities to those described from coeval assemblages from around the world (e.g., England and South Wales; Tripolitania, Libya; Cornwallis Island, Canadian Arctic; Northwest Spain). The rare cryptospore, only one specimen (Tetrahedraletes sp.) had been found to be associated with the Chinese trilete spore assemblage. The discovery of the trilete spores from Late Silurian rocks indicates the existence of early land plants, some possibly vascular, at that time in northern Jiangsu, China.

  17. Small Probes for Orbital Return of Experiments (SPORE), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Analogous to the CubeSat standardization of micro-satellites, the SPORE flight system architecture will utilize a modular design approach to provide low-cost...

  18. Waterline ATS B. globigii spore water disinfection data

    Data.gov (United States)

    U.S. Environmental Protection Agency — Disinfection of B. globigii spores (a non-pathogenic surrogate for B. anthracis) in clean and dirty water using the ATS-Waterline system, which uses ultraviolet...

  19. Architecture and Assembly of the Bacillus subtilis Spore Coat

    Science.gov (United States)

    Plomp, Marco; Carroll, Alicia Monroe; Setlow, Peter; Malkin, Alexander J.

    2014-01-01

    Bacillus spores are encased in a multilayer, proteinaceous self-assembled coat structure that assists in protecting the bacterial genome from stresses and consists of at least 70 proteins. The elucidation of Bacillus spore coat assembly, architecture, and function is critical to determining mechanisms of spore pathogenesis, environmental resistance, immune response, and physicochemical properties. Recently, genetic, biochemical and microscopy methods have provided new insight into spore coat architecture, assembly, structure and function. However, detailed spore coat architecture and assembly, comprehensive understanding of the proteomic composition of coat layers, and specific roles of coat proteins in coat assembly and their precise localization within the coat remain in question. In this study, atomic force microscopy was used to probe the coat structure of Bacillus subtilis wild type and cotA, cotB, safA, cotH, cotO, cotE, gerE, and cotE gerE spores. This approach provided high-resolution visualization of the various spore coat structures, new insight into the function of specific coat proteins, and enabled the development of a detailed model of spore coat architecture. This model is consistent with a recently reported four-layer coat assembly and further adds several coat layers not reported previously. The coat is organized starting from the outside into an outermost amorphous (crust) layer, a rodlet layer, a honeycomb layer, a fibrous layer, a layer of “nanodot” particles, a multilayer assembly, and finally the undercoat/basement layer. We propose that the assembly of the previously unreported fibrous layer, which we link to the darkly stained outer coat seen by electron microscopy, and the nanodot layer are cotH- and cotE- dependent and cotE-specific respectively. We further propose that the inner coat multilayer structure is crystalline with its apparent two-dimensional (2D) nuclei being the first example of a non-mineral 2D nucleation crystallization

  20. Architecture and assembly of the Bacillus subtilis spore coat.

    Science.gov (United States)

    Plomp, Marco; Carroll, Alicia Monroe; Setlow, Peter; Malkin, Alexander J

    2014-01-01

    Bacillus spores are encased in a multilayer, proteinaceous self-assembled coat structure that assists in protecting the bacterial genome from stresses and consists of at least 70 proteins. The elucidation of Bacillus spore coat assembly, architecture, and function is critical to determining mechanisms of spore pathogenesis, environmental resistance, immune response, and physicochemical properties. Recently, genetic, biochemical and microscopy methods have provided new insight into spore coat architecture, assembly, structure and function. However, detailed spore coat architecture and assembly, comprehensive understanding of the proteomic composition of coat layers, and specific roles of coat proteins in coat assembly and their precise localization within the coat remain in question. In this study, atomic force microscopy was used to probe the coat structure of Bacillus subtilis wild type and cotA, cotB, safA, cotH, cotO, cotE, gerE, and cotE gerE spores. This approach provided high-resolution visualization of the various spore coat structures, new insight into the function of specific coat proteins, and enabled the development of a detailed model of spore coat architecture. This model is consistent with a recently reported four-layer coat assembly and further adds several coat layers not reported previously. The coat is organized starting from the outside into an outermost amorphous (crust) layer, a rodlet layer, a honeycomb layer, a fibrous layer, a layer of "nanodot" particles, a multilayer assembly, and finally the undercoat/basement layer. We propose that the assembly of the previously unreported fibrous layer, which we link to the darkly stained outer coat seen by electron microscopy, and the nanodot layer are cotH- and cotE- dependent and cotE-specific respectively. We further propose that the inner coat multilayer structure is crystalline with its apparent two-dimensional (2D) nuclei being the first example of a non-mineral 2D nucleation crystallization

  1. Thermal inactivation kinetics of Bacillus coagulans spores in tomato juice.

    Science.gov (United States)

    Peng, Jing; Mah, Jae-Hyung; Somavat, Romel; Mohamed, Hussein; Sastry, Sudhir; Tang, Juming

    2012-07-01

    The thermal characteristics of the spores and vegetative cells of three strains of Bacillus coagulans (ATCC 8038, ATCC 7050, and 185A) in tomato juice were evaluated. B. coagulans ATCC 8038 was chosen as the target microorganism for thermal processing of tomato products due to its spores having the highest thermal resistance among the three strains. The thermal inactivation kinetics of B. coagulans ATCC 8038 spores in tomato juice between 95 and 115°C were determined independently in two different laboratories using two different heating setups. The results obtained from both laboratories were in general agreement, with z-values (z-value is defined as the change in temperature required for a 10-fold reduction of the D-value, which is defined as the time required at a certain temperature for a 1-log reduction of the target microorganisms) of 8.3 and 8.7°C, respectively. The z-value of B. coagulans 185A spores in tomato juice (pH 4.3) was found to be 10.2°C. The influence of environmental factors, including cold storage time, pH, and preconditioning, upon the thermal resistance of these bacterial spores is discussed. The results obtained showed that a storage temperature of 4°C was appropriate for maintaining the viability and thermal resistance of B. coagulans ATCC 8038 spores. Acidifying the pH of tomato juice decreased the thermal resistance of these spores. A 1-h exposure at room temperature was considered optimal for preconditioning B. coagulans ATCC 8038 spores in tomato juice.

  2. Purification and Properties of Clostridium perfringens Spore Lytic Enzymes.

    Science.gov (United States)

    1983-01-01

    reaction mixture at 550C gave the opti- mum response although the activity of initiation protein remained high at 65"C and 75"C. Denaturation of the...CASSIER M. and Sebald M. 1969. Germination Iysozyme-ddpendente des spores de aCnerilim perfringeno ATCC 3624 sprks tralitment thermique . Ann. Inst. Pasteur...activity upon prolonged extraction -of spores in GME was not surprising, since this compound is an active protein denaturant . Urea acts in the same

  3. Fate of ingested Clostridium difficile spores in mice.

    Directory of Open Access Journals (Sweden)

    Amber Howerton

    Full Text Available Clostridium difficile infection (CDI is a leading cause of antibiotic-associated diarrhea, a major nosocomial complication. The infective form of C. difficile is the spore, a dormant and resistant structure that forms under stress. Although spore germination is the first committed step in CDI onset, the temporal and spatial distribution of ingested C. difficile spores is not clearly understood. We recently reported that CamSA, a synthetic bile salt analog, inhibits C. difficile spore germination in vitro and in vivo. In this study, we took advantage of the anti-germination activity of bile salts to determine the fate of ingested C. difficile spores. We tested four different bile salts for efficacy in preventing CDI. Since CamSA was the only anti-germinant tested able to prevent signs of CDI, we characterized CamSa's in vitro stability, distribution, and cytotoxicity. We report that CamSA is stable to simulated gastrointestinal (GI environments, but will be degraded by members of the natural microbiota found in a healthy gut. Our data suggest that CamSA will not be systemically available, but instead will be localized to the GI tract. Since in vitro pharmacological parameters were acceptable, CamSA was used to probe the mouse model of CDI. By varying the timing of CamSA dosage, we estimated that C. difficile spores germinated and established infection less than 10 hours after ingestion. We also showed that ingested C. difficile spores rapidly transited through the GI tract and accumulated in the colon and cecum of CamSA-treated mice. From there, C. difficile spores were slowly shed over a 96-hour period. To our knowledge, this is the first report of using molecular probes to obtain disease progression information for C. difficile infection.

  4. Measurement of bovine body and scrotal temperature using implanted temperature sensitive radio transmitters, data loggers and infrared thermography.

    Science.gov (United States)

    Wallage, A L; Gaughan, J B; Lisle, A T; Beard, L; Collins, C W; Johnston, S D

    2017-07-01

    Synchronous and continuous measurement of body (BT) and scrotal temperature (ST) without adverse welfare or behavioural interference is essential for understanding thermoregulation of the bull testis. This study compared three technologies for their efficacy for long-term measurement of the relationship between BT and ST by means of (1) temperature sensitive radio transmitters (RT), (2) data loggers (DL) and (3) infrared imaging (IRI). After an initial pilot study on two bulls to establish a surgical protocol, RTs and DLs were implanted into the flank and mid-scrotum of six Wagyu bulls for between 29 and 49 days. RT frequencies were scanned every 15 min, whilst DLs logged every 30 min. Infrared imaging of the body (flank) and scrotum of each bull was recorded hourly for one 24-h period and compared to RT and DL data. After a series of subsequent heat stress studies, bulls were castrated and testicular tissue samples processed for evidence of histopathology. Radio transmitters were less reliable than DLs; RTs lost >11 % of data, whilst 11 of the 12 DLs had 0 % data loss. IRI was only interpretable in 35.8 % of images recorded. Pearson correlations between DL and RT were strong for both BT (r > 0.94, P  0.80, P < 0.001). Surgery produced temporary minor inflammation and scrotal hematoma in two animals post-surgery. Whilst scar tissue was observed at all surgical sutured sites when bulls were castrated, there was no evidence of testicular adhesion and normal active spermatogenesis was observed in six of the eight implanted testicles. There was no significant correlation of IRI with either DL or RT. We conclude that DLs provided to be a reliable continuous source of data for synchronous measurement of BT and ST.

  5. Characterization of the rate and temperature sensitivities of bacterial remineralization of dissolved organic phosphorus by natural populations

    Directory of Open Access Journals (Sweden)

    Angelicque E. White

    2012-08-01

    Full Text Available Production, transformation, and degradation are the principal components of the cycling of dissolved organic matter (DOM in marine systems. Heterotrophic Bacteria (and Archaea play a large part in this cycling via enzymatic decomposition and intracellular transformations of organic material to inorganic carbon (C, nitrogen (N , and phosphorus (P. The rate and magnitude of inorganic nutrient regeneration from DOM is related to the elemental composition and lability of DOM substrates as well as the nutritional needs of the mediating organisms. While many previous efforts have focused on C and N cycling of DOM, less is known in regards to the controls of organic P utilization and remineralization by natural populations of bacteria. In order to constrain the relative time scales and degradation of select dissolved organic P (DOP compounds we have conducted a series of experiments focused on (1 assessment of the short-term lability of a range of DOP compounds, (2 characterization of labile DOP remineralization rates and (3 examination of temperature sensitivities of labile DOP remineralization for varying bacterial populations. Results reinforce previous findings of monoester and polyphosphate lability and the relative recalcitrance of a model phosphonate: 2-aminoethylphosphonate. High resolution time-series of P monoester remineralization indicates decay constants on the order of 0.67-7.04 d-1 for bacterial populations isolated from coastal and open ocean surface waters. The variability of these rates is predictably related to incubation temperature and initial concentrations of heterotrophic bacteria. Additional controls on DOP hydrolysis included seasonal shifts in bacterial populations and the physiological state of bacteria at the initiation of DOP addition experiments. Composite results indicate that bacterial hydrolysis of P-monoesters exceeds bacterial P demand and thus DOP remineralization efficiency may control P availability to autotrophs.

  6. Temperature sensitive lethal factors and puparial colour sex separation mechanisms in the Mediterranean fruit fly, Ceratitis capitata (Wied.)

    International Nuclear Information System (INIS)

    Busch-Petersen, E.

    1990-01-01

    A programme to develop genetic sexing mechanisms in the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), was initiated at the IAEA Laboratories, Seibersdorf, in 1983. Because of the potential benefits arising from the elimination of females early in the developmental cycle, combined with the anticipated relative ease of inducing temperature sensitive lethal (tsl) factors, it was decided to attempt to induce and isolate tsl factors active in the egg or early larval stages. Initially, five recombination suppressor (RS) strains were isolated. The degree of recombination suppression ranged from 77.6% to 99.1%. The viability of each of the five RS strains was assessed and RS 30/55 was selected as the most suitable strain. Ethyl methanesulphonate (EMS) was used to induce the tsl factors, by feeding two-day old adult males with a suspension of EMS in a 10% solution of sugar in the drinking water supply. Temperature tolerance tests indicated a discriminating temperature of 32 deg. C when isolating tsl factors active in the egg stage and 35 deg. C when isolating such factors in the early larval stage. A total of 39 and 22 tsl factors have been isolated in the two stages, respectively. However, none has yet proved stable. Induction of tsl factors with a reduced dose of EMS is now being attempted. An alternative genetic sexing programme was initiated in 1985, based on the use of pupal colour dimorphisms. Previously, a genetic sexing strain, T:Y(wp + )101, based on a white female/brown male puparial colour dimorphism, had twice been assessed for stability under mass rearing conditions. In both cases the sexual colour dimorphism disintegrated immediately. Another similarly dimorphic strain, T:Y(wp + )30C, was developed. This strain remained stable for seven generations of mass rearing, after which it started to disintegrate. Disintegration of this strain was probably caused by accidental contamination by wild type medflies. 34 refs, 1 fig., 1 tab

  7. Measurement of bovine body and scrotal temperature using implanted temperature sensitive radio transmitters, data loggers and infrared thermography

    Science.gov (United States)

    Wallage, A. L.; Gaughan, J. B.; Lisle, A. T.; Beard, L.; Collins, C. W.; Johnston, S. D.

    2017-07-01

    Synchronous and continuous measurement of body (BT) and scrotal temperature (ST) without adverse welfare or behavioural interference is essential for understanding thermoregulation of the bull testis. This study compared three technologies for their efficacy for long-term measurement of the relationship between BT and ST by means of (1) temperature sensitive radio transmitters (RT), (2) data loggers (DL) and (3) infrared imaging (IRI). After an initial pilot study on two bulls to establish a surgical protocol, RTs and DLs were implanted into the flank and mid-scrotum of six Wagyu bulls for between 29 and 49 days. RT frequencies were scanned every 15 min, whilst DLs logged every 30 min. Infrared imaging of the body (flank) and scrotum of each bull was recorded hourly for one 24-h period and compared to RT and DL data. After a series of subsequent heat stress studies, bulls were castrated and testicular tissue samples processed for evidence of histopathology. Radio transmitters were less reliable than DLs; RTs lost >11 % of data, whilst 11 of the 12 DLs had 0 % data loss. IRI was only interpretable in 35.8 % of images recorded. Pearson correlations between DL and RT were strong for both BT ( r > 0.94, P 0.80, P animals post-surgery. Whilst scar tissue was observed at all surgical sutured sites when bulls were castrated, there was no evidence of testicular adhesion and normal active spermatogenesis was observed in six of the eight implanted testicles. There was no significant correlation of IRI with either DL or RT. We conclude that DLs provided to be a reliable continuous source of data for synchronous measurement of BT and ST.

  8. [Impacts of land-use types on soil C mineralization and temperature sensitivity of forests in Qianyanzhou, Jiangxi Province, China].

    Science.gov (United States)

    Li, Jie; Wei, Xue-Hong; Chai, Hua; Wang, Ruo-Meng; Wang, Dan; He, Nian-Peng

    2014-07-01

    Decomposition of soil organic matter plays an important role in the regulation of carbon (C) cycles at ecosystem or regional scales, and is closely related to temperature, moisture, and land-use types. The influences of soil temperature, moisture, and land-use types on soil C mineralization in Citrus reticulata and Pinus elliottii forests were investigated at the Qianyanzhou Ecological Experiment Station, Chinese Academy of Sciences, by conducting incubation experiments at 5-level temperatures (5, 10, 15, 20 and 25 degrees C) and 3-level moistures (30%, 60% and 90% saturated soil moisture, SSM). The results showed that soil temperature, moisture, and land-use types had significant effects on soil C mineralization and they had significant interaction effects. Soil C mineralization was positively correlated with incubation temperature in the two forests, and the maximum of soil C mineralization was in the 60% SSM treatment. The accumulation of soil C mineralization was higher in the C. reticulata forest than in the P. elliottii forest under the same temperature and moisture conditions. The temperature sensitivity (Q10) of soil C mineralization was influenced by land-use type and soil moisture. Q10 increased with the increasing soil moisture in both C. reticulata and P. elliottii forests at incubation 7 and 42 d. Q10 in the C. reticulata forest was higher than in the P. elliottii forest in the same moisture level, and the deviation increased with the increasing soil moisture. The model including temperature and moisture could depict the response of soil C mineralization to temperature and moisture. Temperature and moisture together explained 79.9% -91.9% of the variation in soil C mineralization.

  9. Small acid soluble proteins for rapid spore identification.

    Energy Technology Data Exchange (ETDEWEB)

    Branda, Steven S.; Lane, Todd W.; VanderNoot, Victoria A.; Jokerst, Amanda S.

    2006-12-01

    This one year LDRD addressed the problem of rapid characterization of bacterial spores such as those from the genus Bacillus, the group that contains pathogenic spores such as B. anthracis. In this effort we addressed the feasibility of using a proteomics based approach to spore characterization using a subset of conserved spore proteins known as the small acid soluble proteins or SASPs. We proposed developing techniques that built on our previous expertise in microseparations to rapidly characterize or identify spores. An alternative SASP extraction method was developed that was amenable to both the subsequent fluorescent labeling required for laser-induced fluorescence detection and the low ionic strength requirements for isoelectric focusing. For the microseparations, both capillary isoelectric focusing and chip gel electrophoresis were employed. A variety of methods were evaluated to improve the molecular weight resolution for the SASPs, which are in a molecular weight range that is not well resolved by the current methods. Isoelectric focusing was optimized and employed to resolve the SASPs using UV absorbance detection. Proteomic signatures of native wild type Bacillus spores and clones genetically engineered to produce altered SASP patterns were assessed by slab gel electrophoresis, capillary isoelectric focusing with absorbance detection as well as microchip based gel electrophoresis employing sensitive laser-induced fluorescence detection.

  10. Tip-enhanced Raman scattering of bacillus subtilis spores

    Science.gov (United States)

    Rusciano, G.; Zito, G.; Pesce, G.; Sasso, A.; Isticato, R.; Ricca, E.

    2015-07-01

    Understanding of the complex interactions of molecules at biological interfaces is a fundamental issue in biochemistry, biotechnology as well as biomedicine. A plethora of biological processes are ruled by the molecular texture of cellular membrane: cellular communications, drug transportations and cellular recognition are just a few examples of such chemically-mediated processes. Tip-Enhanced Raman Scattering (TERS) is a novel, Raman-based technique which is ideally suited for this purpose. TERS relies on the combination of scanning probe microscopy and Raman spectroscopy. The basic idea is the use of a metalled tip as a sort of optical nano-antenna, which gives place to SERS effect close to the tip end. Herein, we present the application of TERS to analyze the surface of Bacillus subtilis spores. The choice of this biological systems is related to the fact that a number of reasons support the use of spores as a mucosal delivery system. The remarkable and well-documented resistance of spores to various environmental and toxic effects make them clear potentials as a novel, surface-display system. Our experimental outcomes demonstrate that TERS is able to provide a nano-scale chemical imaging of spore surface. Moreover, we demonstrate that TERS allows differentiation between wilde-type spore and genetically modified strains. These results hold promise for the characterization and optimization of spore surface for drug-delivery applications.

  11. Infrared Signatures to Discriminate Viability of Autoclaved Bacillus Spores

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Matthew D.; Valentine, Nancy B.; Johnson, Timothy J.

    2011-10-06

    Optical methods can offer good sensitivity for detecting small amounts of chemicals and biologicals, and as these methods mature, are some of the few techniques that can offer true standoff detection. For detection of biological species, determining the viability is clearly important: Certain species of gram-positive bacteria are capable of forming endospores, specialized structures that arise when living conditions become unfavorable or little growth medium is available, being resistant to many chemicals as well as changes in heat or pH. Such spores can remain dormant from months to years until more favorable conditions arise, resulting in germination back to the vegetative state. This persistence characteristic of bacterial spores allows for contamination of a surface (e.g. food or medical equipment) even after the surface has been nominally cleaned. Bacterial spores have also been used as biological weapons, as in the case with B. anthracis. Thus, rapid analysis to determine a spore's viability in a given environment or after attempts to sterilize a given environment is crucial. The increasing availability of portable spectrometers may provide a key to such rapid onsite analysis. The present study was designed to determine whether infrared spectroscopy may be used to differentiate between viable vs. dead B. subtilis and B. atrophaeus spores. Preliminary results show that the reproducible differences in the IR signatures can be used to identify viable vs. autoclaved (dead) B. subtilis and B. atrophaeus bacterial spores.

  12. Maternal parentage influences spore production but not spore pigmentation in the anisogamous and hermaphroditic fungus Neurospora crassa

    DEFF Research Database (Denmark)

    Zimmerman, Kolea; Levitis, Daniel; Pringle, Anne

    2014-01-01

    , and various ascospore characteristics. Mixed effects models of these data show that the female parent accounts for the majority of variation in perithecial production, number of spores produced, and spore germination. Surprisingly, both sexes equally influence the percentage of spores that are pigmented......In this study, we tested the hypothesis that maternal effects on offspring production and quality are greater than paternal effects in both offspring number (fertility) and offspring viability (mortality). We used the model filamentous fungus Neurospora crassa. This fungus is anisogamous......, Hall, & Kowbel 2011). Precise genetic distances between mating pairs were calculated to control for the effects of crossing distance on offspring production. We performed reciprocal crosses of all 121 strain pairings and collected data on perithecial production, ascospore (sexual spore) production...

  13. Contrasting effects of elevated CO2 and warming on temperature sensitivity of soil organic matter decomposition in a Chinese paddy field.

    Science.gov (United States)

    Chen, Zhaozhi; Wang, Bingyu; Wang, Jinyang; Pan, Genxing; Xiong, Zhengqin

    2015-10-01

    Climate changes including elevated CO2 and temperature have been known to affect soil carbon (C) storage, while the effects of climate changes on the temperature sensitivity of soil organic matter (SOM) are unclear. A 365-day laboratory incubation was used to investigate the temperature sensitivity for decomposition of labile (Q 10-L) and recalcitrant (Q 10-R) SOMs by comparing the time required to decompose a given amount of C at 25 and 35 °C. Soils were collected from a paddy field that was subjected to four treatments: ambient CO2 and temperature, elevated CO2 (500 μmol/mol), enhanced temperature (+2 °C), and their combination. The results showed that the temperature sensitivity of SOM decomposition increased with increasing SOM recalcitrance in this paddy soil (Q 10-L = 2.21 ± 0.16 vs. Q 10-R = 2.78 ± 0.42; mean ± SD). Elevated CO2 and enhanced temperature showed contrasting effects on the temperature sensitivity of SOM decomposition. Elevated CO2 stimulated Q 10-R but had no effect on Q 10-L; in contrast, enhanced temperature increased Q 10-L but had no effect on Q 10-R. Furthermore, the elevated CO2 combined with enhanced temperature treatment significantly increased Q 10-L and Q 10-R by 18.9 and 10.2 %, respectively, compared to the ambient conditions. Results suggested that the responses of SOM to temperature, especially for the recalcitrant SOM pool, were altered by climate changes. The greatly enhanced temperature sensitivity of SOM decomposition by elevated CO2 and temperature indicates that more CO2 will be released to the atmosphere and losses of soil C may be even greater than that previously expected in paddy field.

  14. Inactivation of Spores of Bacillus Species by Wet Heat: Studies on Single Spores Using Laser Tweezers Taman Spectroscopy

    Science.gov (United States)

    2013-02-01

    13/2011 22.00 Keren K. Griffiths, Jingqiao Zhang, Ann E. Cowan, Ji Yu, Peter Setlow. Germination proteins in the inner membrane of dormant Bacillus...that this technique can be used to rapidly identify single airborne particles or bacteria collected on a slide and to monitor germination dynamics of...the environment of dipicolinic acid in the core of superdormant spores is different from that in dormant spores [J. Bacteriol., 191, 5584 (2009

  15. Improvement of Biological Indicators by Uniformly Distributing Bacillus subtilis Spores in Monolayers To Evaluate Enhanced Spore Decontamination Technologies.

    Science.gov (United States)

    Raguse, Marina; Fiebrandt, Marcel; Stapelmann, Katharina; Madela, Kazimierz; Laue, Michael; Lackmann, Jan-Wilm; Thwaite, Joanne E; Setlow, Peter; Awakowicz, Peter; Moeller, Ralf

    2016-01-22

    Novel decontamination technologies, including cold low-pressure plasma and blue light (400 nm), are promising alternatives to conventional surface decontamination methods. However, the standardization of the assessment of such sterilization processes remains to be accomplished. Bacterial endospores of the genera Bacillus and Geobacillus are frequently used as biological indicators (BIs) of sterility. Ensuring standardized and reproducible BIs for reliable testing procedures is a significant problem in industrial settings. In this study, an electrically driven spray deposition device was developed, allowing fast, reproducible, and homogeneous preparation of Bacillus subtilis 168 spore monolayers on glass surfaces. A detailed description of the structural design as well as the operating principle of the spraying device is given. The reproducible formation of spore monolayers of up to 5 × 10(7) spores per sample was verified by scanning electron microscopy. Surface inactivation studies revealed that monolayered spores were inactivated by UV-C (254 nm), low-pressure argon plasma (500 W, 10 Pa, 100 standard cubic cm per min), and blue light (400 nm) significantly faster than multilayered spores were. We have thus succeeded in the uniform preparation of reproducible, highly concentrated spore monolayers with the potential to generate BIs for a variety of nonpenetrating surface decontamination techniques. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  16. Challenges and advances in systems biology analysis of Bacillus spore physiology; molecular differences between an extreme heat resistant spore forming Bacillus subtilis food isolate and a laboratory strain

    NARCIS (Netherlands)

    Brul, Stanley; van Beilen, Johan; Caspers, Martien P M; O'Brien, Andrea; de Koster, Chris; Oomes, Suus; Smelt, Jan; Kort, Remco; Ter Beek, Alex

    Bacterial spore formers are prime organisms of concern in the food industry. Spores from the genus Bacillus are extremely stress resistant, most notably exemplified by high thermotolerance. This sometimes allows surviving spores to germinate and grow out to vegetative cells causing food spoilage and

  17. Challenges and advances in systems biology analysis of Bacillus spore physiology; molecular differences between an extreme heat resistant spore forming Bacillus subtilis food isolate and a laboratory strain

    NARCIS (Netherlands)

    Brul, S.; van Beilen, J.; Caspers, M.; O'Brien, A.; de Koster, C.; Oomes, S.; Smelt, J.; Kort, R.; ter Beek, A.

    2011-01-01

    Bacterial spore formers are prime organisms of concern in the food industry. Spores from the genus Bacillus are extremely stress resistant, most notably exemplified by high thermotolerance. This sometimes allows surviving spores to germinate and grow out to vegetative cells causing food spoilage and

  18. Live cell imaging of germination and outgrowth of individual Bacillus subtilis spores; the effect of heat stress quantitatively analyzed with SporeTracker

    NARCIS (Netherlands)

    Pandey, R.; ter Beek, A.; Vischer, N.O.E.; Smelt, J.P.P.M.; Brul, S.; Manders, E.M.M.

    2013-01-01

    Spore-forming bacteria are a special problem for the food industry as some of them are able to survive preservation processes. Bacillus spp. spores can remain in a dormant, stress resistant state for a long period of time. Vegetative cells are formed by germination of spores followed by a more

  19. Toxigenic potential and heat survival of spore-forming bacteria isolated from bread and ingredients.

    Science.gov (United States)

    De Bellis, Palmira; Minervini, Fiorenza; Di Biase, Mariaelena; Valerio, Francesca; Lavermicocca, Paola; Sisto, Angelo

    2015-03-16

    Fifty-four spore-forming bacterial strains isolated from bread ingredients and bread, mainly belonging to the genus Bacillus (including Bacillus cereus), together with 11 reference strains were investigated to evaluate their cytotoxic potential and heat survival in order to ascertain if they could represent a risk for consumer health. Therefore, we performed a screening test of cytotoxic activity on HT-29 cells using bacterial culture filtrates after growing bacterial cells in Brain Heart Infusion medium and in the bread-based medium Bread Extract Broth (BEB). Moreover, immunoassays and PCR analyses, specifically targeting already known toxins and related genes of B. cereus, as well as a heat spore inactivation assay were carried out. Despite of strain variability, the results clearly demonstrated a high cytotoxic activity of B. cereus strains, even if for most of them it was significantly lower in BEB medium. Cytotoxic activity was also detected in 30% of strains belonging to species different from B. cereus, although, with a few exceptions (e.g. Bacillus simplex N58.2), it was low or very low. PCR analyses detected the presence of genes involved in the production of NHE, HBL or CytK toxins in B. cereus strains, while genes responsible for cereulide production were not detected. Production of NHE and HBL toxins was also confirmed by specific immunoassays only for B. cereus strains even if PCR analyses revealed the presence of related toxin genes also in some strains of other species. Viable spore count was ascertained after a heat treatment simulating the bread cooking process. Results indicated that B. amyloliquefaciens strains almost completely survived the heat treatment showing less than 2 log-cycle reductions similarly to two strains of B. cereus group III and single strains belonging to Bacillus subtilis, Bacillus mojavensis and Paenibacillus spp. Importantly, spores from strains of the B. cereus group IV exhibited a thermal resistance markedly lower than B

  20. Old and stable soil organic matter is not necessarily chemically recalcitrant: Implications for modeling concepts and temperature sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Kleber, M.; Nico, P.S.; Plante, A.; Filley, T.; Kramer, M.; Swanston, C.; Sollins, P.

    2010-03-01

    of complex or 'recalcitrant' compounds will erroneously attribute a greater temperature sensitivity to those materials than they may actually possess.

  1. Alginate Microspheres Containing Temperature Sensitive Liposomes (TSL for MR-Guided Embolization and Triggered Release of Doxorubicin.

    Directory of Open Access Journals (Sweden)

    Merel van Elk

    Full Text Available The objective of this study was to develop and characterize alginate microspheres suitable for embolization with on-demand triggered doxorubicin (DOX release and whereby the microspheres as well as the drug releasing process can be visualized in vivo using MRI.For this purpose, barium crosslinked alginate microspheres were loaded with temperature sensitive liposomes (TSL/TSL-Ba-ms, which release their payload upon mild hyperthermia. These TSL contained DOX and [Gd(HPDO3A(H2O], a T1 MRI contrast agent, for real time visualization of the release. Empty alginate microspheres crosslinked with holmium ions (T2* MRI contrast agent, Ho-ms were mixed with TSL-Ba-ms to allow microsphere visualization. TSL-Ba-ms and Ho-ms were prepared with a homemade spray device and sized by sieving. Encapsulation of TSL in barium crosslinked microspheres changed the triggered release properties only slightly: 95% of the loaded DOX was released from free TSL vs. 86% release for TSL-Ba-ms within 30 seconds in 50% FBS at 42°C. TSL-Ba-ms (76 ± 41 μm and Ho-ms (64 ± 29 μm had a comparable size, which most likely will result in a similar in vivo tissue distribution after an i.v. co-injection and therefore Ho-ms can be used as tracer for the TSL-Ba-ms. MR imaging of a TSL-Ba-ms and Ho-ms mixture (ratio 95:5 before and after hyperthermia allowed in vitro and in vivo visualization of microsphere deposition (T2*-weighted images as well as temperature-triggered release (T1-weighted images. The [Gd(HPDO3A(H2O] release and clusters of microspheres containing holmium ions were visualized in a VX2 tumor model in a rabbit using MRI.In conclusion, these TSL-Ba-ms and Ho-ms are promising systems for real-time, MR-guided embolization and triggered release of drugs in vivo.

  2. Temperature sensitivity and basal rate of soil respiration and their determinants in temperate forests of North China.

    Science.gov (United States)

    Zhou, Zhiyong; Guo, Chao; Meng, He

    2013-01-01

    The basal respiration rate at 10°C (R10) and the temperature sensitivity of soil respiration (Q10) are two premier parameters in predicting the instantaneous rate of soil respiration at a given temperature. However, the mechanisms underlying the spatial variations in R10 and Q10 are not quite clear. R10 and Q10 were calculated using an exponential function with measured soil respiration and soil temperature for 11 mixed conifer-broadleaved forest stands and nine broadleaved forest stands at a catchment scale. The mean values of R10 were 1.83 µmol CO2 m(-2) s(-1) and 2.01 µmol CO2 m(-2) s(-1), the mean values of Q10 were 3.40 and 3.79, respectively, for mixed and broadleaved forest types. Forest type did not influence the two model parameters, but determinants of R10 and Q10 varied between the two forest types. In mixed forest stands, R10 decreased greatly with the ratio of coniferous to broadleaved tree species; whereas it sharply increased with the soil temperature range and the variations in soil organic carbon (SOC), and soil total nitrogen (TN). Q10 was positively correlated with the spatial variances of herb-layer carbon stock and soil bulk density, and negatively with soil C/N ratio. In broadleaved forest stands, R10 was markedly affected by basal area and the variations in shrub carbon stock and soil phosphorus (P) content; the value of Q10 largely depended on soil pH and the variations of SOC and TN. 51% of variations in both R10 and Q10 can be accounted for jointly by five biophysical variables, of which the variation in soil bulk density played an overwhelming role in determining the amplitude of variations in soil basal respiration rates in temperate forests. Overall, it was concluded that soil respiration of temperate forests was largely dependent on soil physical properties when temperature kept quite low.

  3. Temperature sensitive liposomes combined with thermal ablation: Effects of duration and timing of heating in mathematical models and in vivo.

    Directory of Open Access Journals (Sweden)

    Christian Rossmann

    Full Text Available Temperature sensitive liposomes (TSL are nanoparticles that rapidly release the contained drug at hyperthermic temperatures, typically above ~40°C. TSL have been combined with various heating modalities, but there is no consensus on required hyperthermia duration or ideal timing of heating relative to TSL administration. The goal of this study was to determine changes in drug uptake when heating duration and timing are varied when combining TSL with radiofrequency ablation (RF heating.We used computer models to simulate both RF tissue heating and TSL drug delivery, to calculate spatial drug concentration maps. We simulated heating for 5, 12 and 30 min for a single RF electrode, as well as three sequential 12 min ablations for 3 electrodes placed in a triangular array. To support simulation results, we performed porcine in vivo studies in normal liver, where TSL filled with doxorubicin (TSL-Dox at a dose of 30 mg was infused over 30 min. Following infusion, RF heating was performed in separate liver locations for either 5 min (n = 2 or 12 min (n = 2. After ablation, the animal was euthanized, and liver extracted and frozen. Liver samples were cut orthogonal to the electrode axis, and fluorescence imaging was used to visualize tissue doxorubicin distribution.Both in vivo studies and computer models demonstrate a ring-shaped drug deposition within ~1 cm of the visibly coagulated tissue. Drug uptake directly correlated with heating duration. In computer simulations, drug concentration increased by a factor of 2.2x and 4.3x when heating duration was extended from 5 to either 12, or 30 minutes, respectively. In vivo, drug concentration was by a factor of 2.4x higher at 12 vs 5 min heating duration (7.1 μg/g to 3.0 μg/g. The computer models suggest that heating should be timed to maximize area under the curve of systemic plasma concentration of encapsulated drug.Both computer models and in vivo study demonstrate that tissue drug uptake directly

  4. Airway inflammation among compost workers exposed to actinomycetes spores.

    Science.gov (United States)

    Heldal, Kari Kulvik; Madsø, Lene; Eduard, Wijnand

    2015-01-01

    To study the associations between exposure to bioaerosols and work-related symptoms, lung function and biomarkers of airway inflammation in compost workers. Personal full-shift exposure measurements were performed on 47 workers employed at five windrow plants (n=20) and five reactor plants (n=27). Samples were analyzed for endotoxins, bacteria, fungal and actinomycetes spores. Health examinations were performed on workers and 37 controls before and after work on the day exposure was measured. The examinations included symptoms recorded by questionnaire, lung function by spirometry and nasal dimensions by acoustic rhinometry (AR). The pneumoproteins CC16, SP-D and SP-A were measured in a blood sample drawn at the end of the day. The levels of endotoxins (median 3 EU/m(3), range 0-730 EU/m(3)) and actinomycetes spores (median 0.2 × 10(6) spores/m(3), range 0-590 × 10(6) spores/m(3)) were significantly higher in reactor plants compared to windrow plants. However, windrow composting workers reported more symptoms than reactor composting workers, probably due to use of respiratory protection. Exposure-response relationships between actinomycetes spores exposure and respiratory effects, found as cough and nose irritation during a shift, was significantly increased (OR 4.3, 95% CI 1.1-16, OR 6.1, 95% CI 1.5-25, respectively, pactinomycetes spores/m3, and FEV1/FVC% decreased cross shift (b=-3.2, SE=1.5%, pactinomycetes spores which was associated with work related cough symptoms and work-shift lung function decrease.

  5. Dynamics of Bacillus thuringiensis var. israelensis and Lysinibacillus sphaericus spores in urban catch basins after simultaneous application against mosquito larvae.

    Science.gov (United States)

    Guidi, Valeria; Lehner, Angelika; Lüthy, Peter; Tonolla, Mauro

    2013-01-01

    Bacillus thuringiensis var. israelensis (Bti) and Lysinibacillus sphaericus (Lsph) are extensively used in mosquito control programs. These biocides are the active ingredients of a commercial larvicide. Quantitative data on the fate of both Bti and Lsph applied together for the control of mosquitoes in urban drainage structures such as catch basins are lacking. We evaluated the dynamics and persistence of Bti and Lsph spores released through their concomitant application in urban catch basins in southern Switzerland. Detection and quantification of spores over time in water and sludge samples from catch basins were carried out using quantitative real-time PCR targeting both cry4A and cry4B toxin genes for Bti and the binA gene for Lsph. After treatment, Bti and Lsph spores attained concentrations of 3.76 (± 0.08) and 4.13 (± 0.09) log ml(-1) in water, then decreased progressively over time, reaching baseline values. For both Bti and Lsph, spore levels in the order of 10(5) g(-1) were observed in the bottom sludge two days after the treatment and remained constant for the whole test period (275 days). Indigenous Lsph strains were isolated from previously untreated catch basins. A selection of those was genotyped using pulsed field gel electrophoresis of SmaI-digested chromosomal DNA, revealing that a subset of isolates were members of the clonal population of strain 2362. No safety issues related to the use of this biopesticide in the environment have been observed during this study, because no significant increase in the number of spores was seen during the long observation period. The isolation of native Lysinibacillus sphaericus strains belonging to the same clonal population as strain 2362 from catch basins never treated with Lsph-based products indicates that the use of a combination of Bti and Lsph for the control of mosquitoes does not introduce non-indigenous microorganisms in this area.

  6. Dynamics of Bacillus thuringiensis var. israelensis and Lysinibacillus sphaericus spores in urban catch basins after simultaneous application against mosquito larvae.

    Directory of Open Access Journals (Sweden)

    Valeria Guidi

    Full Text Available Bacillus thuringiensis var. israelensis (Bti and Lysinibacillus sphaericus (Lsph are extensively used in mosquito control programs. These biocides are the active ingredients of a commercial larvicide. Quantitative data on the fate of both Bti and Lsph applied together for the control of mosquitoes in urban drainage structures such as catch basins are lacking. We evaluated the dynamics and persistence of Bti and Lsph spores released through their concomitant application in urban catch basins in southern Switzerland. Detection and quantification of spores over time in water and sludge samples from catch basins were carried out using quantitative real-time PCR targeting both cry4A and cry4B toxin genes for Bti and the binA gene for Lsph. After treatment, Bti and Lsph spores attained concentrations of 3.76 (± 0.08 and 4.13 (± 0.09 log ml(-1 in water, then decreased progressively over time, reaching baseline values. For both Bti and Lsph, spore levels in the order of 10(5 g(-1 were observed in the bottom sludge two days after the treatment and remained constant for the whole test period (275 days. Indigenous Lsph strains were isolated from previously untreated catch basins. A selection of those was genotyped using pulsed field gel electrophoresis of SmaI-digested chromosomal DNA, revealing that a subset of isolates were members of the clonal population of strain 2362. No safety issues related to the use of this biopesticide in the environment have been observed during this study, because no significant increase in the number of spores was seen during the long observation period. The isolation of native Lysinibacillus sphaericus strains belonging to the same clonal population as strain 2362 from catch basins never treated with Lsph-based products indicates that the use of a combination of Bti and Lsph for the control of mosquitoes does not introduce non-indigenous microorganisms in this area.

  7. Fungal spores in four catholic churches in the metropolitan area of Monterrey, Nuevo León State, Mexico – First study

    Directory of Open Access Journals (Sweden)

    Alejandra Rocha Estrada

    2015-05-01

    Full Text Available Introduction. About 500,000 species of fungi have been described to-date, although an estimated between 1 – 1.5 million species may occur. They have a wide distribution in nature, contributing to the decomposition of organic matter and playing a part in the biogeochemical cycles of major nutrients. A small number are considered pathogens of animals and plants. There is ample historical evidence that certain types of allergies are associated with fungi; exposure to fungal allergens occurs in both outdoor and indoor spaces. Many indoor allergens are the same as those found outside buildings, entering through windows and doors, ventilation systems, or through cracks or other fissures in the walls. Objective. To determine the diversity and abundance of fungal spores inside four churches in the metropolitan area of Monterrey city in Mexico. Materials and methods. The study was carried out from July 2009 – January 2010 using a Hirst type volumetric collector (Burkard Manufacturing Co Ltd. Results. A total of 31,629 spores from 54 taxa were registered in the four churches. The building that showed the highest amount of spores was the Santa Catarina Mártir Church with 12,766 spores, followed by Cristo Rey with 7,155 and Nuestra Señora del Roble with 6,887. Regularly high concentrations of spores were recorded from 14:00 – 20:00 hours. The highest concentration value was observed at the church of Santa Catarina Mártir at 16:00 hours with 1153 spores/m 3 air. Conclusions. The most abundant spores in the four churches studied corresponded to Cladosporium, the [i]Aspergillus/Penicillium complex[/i], [i]Coprinus[/i], [i]Ganoderma[/i], [i]Curvularia and Ustilago[/i].

  8. Fighting Ebola with novel spore decontamination technologies for the military

    Science.gov (United States)

    Doona, Christopher J.; Feeherry, Florence E.; Kustin, Kenneth; Olinger, Gene G.; Setlow, Peter; Malkin, Alexander J.; Leighton, Terrance

    2015-01-01

    Recently, global public health organizations such as Doctors without Borders (MSF), the World Health Organization (WHO), Public Health Canada, National Institutes of Health (NIH), and the U.S. government developed and deployed Field Decontamination Kits (FDKs), a novel, lightweight, compact, reusable decontamination technology to sterilize Ebola-contaminated medical devices at remote clinical sites lacking infra-structure in crisis-stricken regions of West Africa (medical waste materials are placed in bags and burned). The basis for effectuating sterilization with FDKs is chlorine dioxide (ClO2) produced from a patented invention developed by researchers at the US Army Natick Soldier RD&E Center (NSRDEC) and commercialized as a dry mixed-chemical for bacterial spore decontamination. In fact, the NSRDEC research scientists developed an ensemble of ClO2 technologies designed for different applications in decontaminating fresh produce; food contact and handling surfaces; personal protective equipment; textiles used in clothing, uniforms, tents, and shelters; graywater recycling; airplanes; surgical instruments; and hard surfaces in latrines, laundries, and deployable medical facilities. These examples demonstrate the far-reaching impact, adaptability, and versatility of these innovative technologies. We present herein the unique attributes of NSRDEC’s novel decontamination technologies and a Case Study of the development of FDKs that were deployed in West Africa by international public health organizations to sterilize Ebola-contaminated medical equipment. FDKs use bacterial spores as indicators of sterility. We review the properties and structures of spores and the mechanisms of bacterial spore inactivation by ClO2. We also review mechanisms of bacterial spore inactivation by novel, emerging, and established non-thermal technologies for food preservation, such as high pressure processing, irradiation, cold plasma, and chemical sanitizers, using an array of Bacillus

  9. Scanning Surface Potential Microscopy of Spore Adhesion on Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ida [University of Tennessee, Knoxville (UTK); Chung, Eunhyea [Georgia Institute of Technology; Kweon, Hyojin [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Tsouris, Costas [ORNL

    2012-01-01

    The adhesion of spores of Bacillus anthracis - the cause of anthrax and a likely biological threat - to solid surfaces is an important consideration in cleanup after an accidental or deliberate release. However, because of safety concerns, directly studying B. anthracis spores with advanced instrumentation is problematic. As a first step, we are examining the electrostatic potential of Bacillus thuringiensis (Bt), which is a closely related species that is often used as a simulant to study B. anthracis. Scanning surface potential microscopy (SSPM), also known as Kelvin probe force microscopy (KPFM), was used to investigate the influence of relative humidity (RH) on the surface electrostatic potential of Bt that had adhered to silica, mica, or gold substrates. AFM/SSPM side-by-side images were obtained separately in air, at various values of RH, after an aqueous droplet with spores was applied on each surface and allowed to dry before measurements. In the SSPM images, a negative potential on the surface of the spores was observed compared with that of the substrates. The surface potential decreased as the humidity increased. Spores were unable to adhere to a surface with an extremely negative potential, such as mica.

  10. Scanning surface potential microscopy of spore adhesion on surfaces.

    Science.gov (United States)

    Lee, I; Chung, E; Kweon, H; Yiacoumi, S; Tsouris, C

    2012-04-01

    The adhesion of spores of Bacillus anthracis - the cause of anthrax and a likely biological threat - to solid surfaces is an important consideration in cleanup after an accidental or deliberate release. However, because of safety concerns, directly studying B. anthracis spores with advanced instrumentation is problematic. As a first step, we are examining the electrostatic potential of Bacillus thuringiensis (Bt), which is a closely related species that is often used as a simulant to study B. anthracis. Scanning surface potential microscopy (SSPM), also known as Kelvin probe force microscopy (KPFM), was used to investigate the influence of relative humidity (RH) on the surface electrostatic potential of Bt that had adhered to silica, mica, or gold substrates. AFM/SSPM side-by-side images were obtained separately in air, at various values of RH, after an aqueous droplet with spores was applied on each surface and allowed to dry before measurements. In the SSPM images, a negative potential on the surface of the spores was observed compared with that of the substrates. The surface potential decreased as the humidity increased. Spores were unable to adhere to a surface with an extremely negative potential, such as mica. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Detection of Bacillus spores using PCR and FTA filters.

    Science.gov (United States)

    Lampel, Keith A; Dyer, Deanne; Kornegay, Leroy; Orlandi, Palmer A

    2004-05-01

    Emphasis has been placed on developing and implementing rapid detection systems for microbial pathogens. We have explored the utility of expanding FTA filter technology for the preparation of template DNA for PCR from bacterial spores. Isolated spores from several Bacillus spp., B. subtilis, B. cereus, and B. megaterium, were applied to FTA filters, and specific DNA products were amplified by PCR. Spore preparations were examined microscopically to ensure that the presence of vegetative cells, if any, did not yield misleading results. PCR primers SRM86 and SRM87 targeted a conserved region of bacterial rRNA genes, whereas primers Bsub5F and Bsub3R amplified a product from a conserved sequence of the B. subtilis rRNA gene. With the use of the latter set of primers for nested PCR, the sensitivity of the PCR-based assay was increased. Overall, 53 spores could be detected after the first round of PCR, and the sensitivity was increased to five spores by nested PCR. FTA filters are an excellent platform to remove PCR inhibitors and have universal applications for environmental, clinical, and food samples.

  12. Germination of Bacillus cereus spores adhered to stainless steel.

    Science.gov (United States)

    Hornstra, L M; de Leeuw, P L A; Moezelaar, R; Wolbert, E J; de Vries, Y P; de Vos, W M; Abee, T

    2007-05-30

    Adhered spores of Bacillus cereus represent a significant part of the surface-derived contamination in processing equipment used in the dairy industry. As germinated spores lose their resistance capacities instantaneously, efficient germination prior to a cleaning in place treatment could aid to the disinfecting effect of such a treatment. Therefore, spores of B. cereus ATCC 14579 and that of the environmental isolate B. cereus CMCC 3328 were assessed for their germination behaviour when adhered to a stainless steel surface. A mixture of l-alanine and inosine initiated germination of adhered spores efficiently, resulting in 3.2 decimal logarithms of germination. Notably, implementation of a germination-inducing step prior to a representative cleaning in place procedure reduced the number of survivors with over 3 decimal log units, while an alkali treatment alone, as part of the cleaning in place procedure, did not show any effect on B. cereus spore viability. These results show that implementation of a germination step enhances the disinfection effect of currently used cleaning in place procedures.

  13. Daily variations of Alternaria spores in the city of Murcia (semi-arid southeastern Spain)

    Science.gov (United States)

    Munuera Giner, M.; Carrión García, J. S.

    1995-12-01

    Annual variations in the abundance of Alternaria spores were related to the length of the spore period for data from Murcia (southeastern Spain). To understand the relationship between the number of spores and climatic factors, Alternaria spore counts for March 1993 to February 1994 were examined by means of correlation and regression analyses with fourteen different weather parameters. The results indicated that there was a tendency for Alternaria spore concentrations to increase with increases in temperature, wind speed and hours of sunshine. Negative correlations were observed with air pressure, wind direction and humidity. Theoretical curves for Alternaria spore counts are given in relation to temperatures during the period studied.

  14. Spore analysis and tetrad dissection of Schizosaccharomyces pombe

    DEFF Research Database (Denmark)

    Ekwall, Karl; Thon, Genevieve

    2017-01-01

    Here we describe the processing of Schizosaccharomyces pombe spores in batches (random spore analysis) or through tetrad dissections. Spores are usually prepared from matings between haploid strains (producing zygotic asci) or from sporulating diploids (producing azygotic asci). In random spore...... analysis, a snail enzyme preparation is used to digest the walls of asci to release free spores that are diluted and plated to form colonies. In tetrad dissection, a needle attached to a micromanipulator is used to pick asci and separate spores. Tetrad dissection has traditionally been the method of choice...

  15. The microbial temperature sensitivity to warming is controlled by thermal adaptation and is independent of C-quality across a pan-continental survey

    Science.gov (United States)

    Berglund, Eva; Rousk, Johannes

    2017-04-01

    Climate models predict that warming will result in an increased loss of soil organic matter (SOM). However, field experiments suggest that although warming results in an immediate increase in SOM turnover, the effect diminishes over time. Although the use and subsequent turnover of SOM is dominated by the soil microbial community, the underlying physiology underpinning warming responses are not considered in current climate models. It has been suggested that a reduction in the perceived quality of SOM to the microbial community, and changes in the microbial thermal adaptation, could be important feed-backs to soil warming. Thus, studies distinguishing between temperature relationships and how substrate quality influences microbial decomposition are a priority. We examined microbial communities and temperature sensitivities along a natural climate gradient including 56 independent samples from across Europe. The gradient included mean annual temperatures (MAT) from ca -4 to 18 ˚ C, along with wide spans of environmental factors known to influence microbial communities, such as pH (4.0 to 8.8), nutrients (C/N from 7 to 50), SOM (from 4 to 94%), and plant communities, etc. The extensive ranges of environmental conditions resulted in wide ranges of substrate quality, indexed as microbial respiration per unit SOM, from 5-150 μg CO2g-1 SOM g-1 h-1. We hypothesised microbial communities to (1) be adapted to the temperature of their climate, leading to warm adapted bacterial communities that were more temperature sensitive (higher Q10s) at higher MAT; (2) have temperature sensitivities affected by the quality of SOM, with higher Q10s for lower quality SOM. To determine the microbial use of SOM and its dependence on temperature, we characterized microbial temperature dependences of bacterial growth (leu inc), fungal growth (ac-in-erg) and soil respiration in all 56 sites. Temperature dependences were determined using brief (ca. 1-2 h at 25˚ C) laboratory incubation

  16. Monitoring temperature sensitivity of soil organic carbon decomposition under maize-wheat cropping systems in semi-arid India.

    Science.gov (United States)

    Sandeep, S; Manjaiah, K M; Mayadevi, M R; Singh, A K

    2016-08-01

    Long-term storage of soil organic carbon (SOC) is essential for sustainability of agricultural ecosystems and maintaining overall environment quality as soils contain a significant part of global carbon stocks. In this study, we attempted to explain the carbon mineralization and temperature sensitivity of SOC in maize-wheat systems, a common cropping system in the semi-arid regions of India. Soil samples(0-0.15 m) from long-term experimental plots laid in split plot design with two tillage systems (conventional tillage and bed planting) and six nutrient management treatments (T 1 = control, T 2 = 120 kg urea-N/ha, T 3 = T2 (25 % N substituted by farmyard manure (FYM)), T 4 = T 2 (25 % N substituted by sewage sludge), T 5 = T 2 + crop residue, T 6 = 100 % recommended doses of N through organic source - 50 % FYM + 25 % biofertilizer + 25 % crop residue) were incubated at different temperatures (25, 30, 35, and 40 °C) to determine the thermal sensitivity parameters associated with carbon mineralization. Earlier reports suggest a selective preservation of C3-derived carbon fractions over C4 in the SOC pool, and this is the first instance where δ (13)C signatures (C4-derived carbon) were used as a qualitative measure to assess thermal sensitivity of SOC pools in the maize-wheat crop rotation systems of semi-arid India. Among the nutrient management treatments, mineral fertilizers were found to add more C4-derived carbon to the SOC pool in both the tillage systems but shows less promise in SOC stability as indicated by their lower activation energies (Ea) (14.25 kJ mol(-1)). Conventional tillage was found to mineralize 18.80 % (T 1-control at 25 °C) to 29.93 % carbon (T 3-mineral fertilizer + FYM at 40 °C) during the 150 days of incubation which was significantly higher than bed planting system (14.90 % in T 1-control at 25 °C and 21.99 % in T 6-100% organic sources at 40 °C). Organic manures, especially FYM (19

  17. Use of a temperature-sensitive p53 mutant to evaluate mechanisms of 5-fluorodeoxyuridine-mediated radiosensitization

    International Nuclear Information System (INIS)

    Naida, J.D.; Davis, M.A.; Lawrence, T.S.

    1996-01-01

    Purpose/Objective: Evidence exists that fluorodeoxyuridine (FdUrd)-mediated radiosensitization occurs in HT29 human colon carcinoma cells (which are p53 mutant) when these cells progress past the G 1 /S boundary in the presence of the drug. It has been demonstrated that wild type p53 levels increase following fluoropyrimidine treatment and that G 1 arrest is associated with increased p53 levels. We hypothesized that the restoration of wild type p53 function might restore G 1 /S arrest after FdUrd treatment, and that this would prevent FdUrd-mediated radiosensitization. Similarly, we hypothesized that cells containing wild type p53 would not be radiosensitized by FdUrd. Materials and Methods: Two clones of HT29 human colon cancer cells (ts29-A and ts29-G) containing murine temperature-sensitive p53 were constructed using electroporation and Geneticin selection. Incubation of these cells at the permissive temperature of 32 deg. C produces wild type p53 function and at the non permissive temperature of 38 deg. C causes mutant p53 function. A G418 resistant control cell line was also constructed (HT29neo). Cells were incubated at either 32 deg. C or 38 deg. C for 24 hours prior to irradiation and with FdUrd (100 nM) or medium only during the last 14 hours of the temperature shift. To assess progression into S phase, single-parameter (propidium iodide (PI)) and two-parameter (PI and bromodeoxyuridine) flow cytometry were performed at the end of drug exposure. A standard clonogenic assay was used. Results: We found that when ts29-A and ts29-G cells were incubated at the non-permissive (inactive p53 conformation) temperature, they progressed into S phase following exposure to FdUrd and were radiosensitized (enhancement ratio 1.5) to a degree similar to that seen in parental HT29 cells. Cells incubated at the permissive (wild-type p53 conformation) temperature demonstrated G 1 arrest, S phase depletion, and G2 arrest. In addition, FdUrd-mediated radiosensitization was

  18. Sensitizing Clostridium difficile Spores With Germinants on Skin and Environmental Surfaces Represents a New Strategy for Reducing Spores via Ambient Mechanisms

    Directory of Open Access Journals (Sweden)

    Michelle Marie Nerandzic

    2017-10-01

    Full Text Available Background: Clostridium difficile is a leading cause of healthcare-associated infections worldwide. Prevention of C. difficile transmission is challenging because spores are not killed by alcohol-based hand sanitizers or many commonly used disinfectants. One strategy to control spores is to induce germination, thereby rendering the spores more susceptible to benign disinfection measures and ambient stressors. Methods/Results: C. difficile spores germinated on skin after a single application of cholic acid-class bile salts and co-germinants; for 4 C. difficile strains, recovery of viable spores from skin was reduced by ~0.3 log10CFU to 2 log10CFU after 2 hours and ~1 log10CFU to >2.5 log 10CFU after 24 hours. The addition of taurocholic acid to 70% and 30% ethanol significantly enhanced reduction of viable spores on skin and on surfaces. Desiccation, and to a lesser extent the presence of oxygen, were identified as the stressors responsible for reductions of germinated spores on skin and surfaces. Additionally, germinated spores became susceptible to killing by pH 1.5 hydrochloric acid, suggesting that germinated spores that remain viable on skin and surfaces might be killed by gastric acid after ingestion. Antibiotic-treated mice did not become colonized after exposure to germinated spores, whereas 100% of mice became colonized after exposure to the same quantity of dormant spores. Conclusions: Germination could provide a new approach to reduce C. difficile spores on skin and in the environment and to render surviving spores less capable of causing infection. Our findings suggest that it may be feasible to develop alcohol-based hand sanitizers containing germinants that reduce spores on hands.

  19. Rapid, Simple and Cost-Effective Molecular Method to Differentiate the Temperature Sensitive (ts+ MS-H Vaccine Strain and Wild-Type Mycoplasma synoviae Isolates.

    Directory of Open Access Journals (Sweden)

    Zsuzsa Kreizinger

    Full Text Available Mycoplasma synoviae infection in chickens and turkeys can cause respiratory disease, infectious synovitis and eggshell apex abnormality; thus it is an economically important pathogen. Control of M. synoviae infection comprises eradication, medication or vaccination. The differentiation of the temperature sensitive (ts+ MS-H vaccine strain from field isolates is crucial during vaccination programs. Melt-curve and agarose gel based mismatch amplification mutation assays (MAMA are provided in the present study to distinguish between the ts+ MS-H vaccine strain, its non-temperature sensitive re-isolates and wild-type M. synoviae isolates based on the single nucleotide polymorphisms at nt367 and nt629 of the obg gene. The two melt-MAMAs and the two agarose-MAMAs clearly distinguish the ts+ MS-H vaccine strain genotype from its non-temperature sensitive re-isolate genotype and wild-type M. synoviae isolate genotype, and no cross-reactions with other Mycoplasma species infecting birds occur. The sensitivity of the melt-MAMAs and agarose-MAMAs was 103 and 104 copy numbers, respectively. The assays can be performed directly on clinical samples and they can be run simultaneously at the same annealing temperature. The assays can be performed in laboratories with limited facilities, using basic real-time PCR machine or conventional thermocycler coupled with agarose gel electrophoresis. The advantages of the described assays compared with previously used methods are simplicity, sufficient sensitivity, time and cost effectiveness and specificity.

  20. Pollen and spores as a passive monitor of ultraviolet radiation

    Directory of Open Access Journals (Sweden)

    Wesley Toby Fraser

    2014-04-01

    Full Text Available Sporopollenin is the primary component of the outer walls of pollen and spores. The chemical composition of sporopollenin is responsive to levels of ultraviolet (UV radiation exposure, via a concomitant change in the concentration of phenolic compounds. This relationship offers the possibility of using fossil pollen and spore chemistry as a novel proxy for past UV flux. Phenolic compounds in sporopollenin can be quantified using Fourier Transform infrared spectroscopy. The high potential for preservation of pollen and spores in the geologic record, and the conservative nature of sporopollenin chemistry across the land plant phylogeny, means that this new proxy has the potential to reconstruct UV flux over much longer timescales than has previously been possible. This new tool has important implications for understanding the relationship between UV flux, solar insolation and climate in the past, as well as providing a possible means of assessing paleoaltitude, and ozone thickness.

  1. Lipoxygenase Activity Accelerates Programmed Spore Germination in Aspergillus fumigatus

    Directory of Open Access Journals (Sweden)

    Gregory J. Fischer

    2017-05-01

    Full Text Available The opportunistic human pathogen Aspergillus fumigatus initiates invasive growth through a programmed germination process that progresses from dormant spore to swollen spore (SS to germling (GL and ultimately invasive hyphal growth. We find a lipoxygenase with considerable homology to human Alox5 and Alox15, LoxB, that impacts the transitions of programmed spore germination. Overexpression of loxB (OE::loxB increases germination with rapid advance to the GL stage. However, deletion of loxB (ΔloxB or its signal peptide only delays progression to the SS stage in the presence of arachidonic acid (AA; no delay is observed in minimal media. This delay is remediated by the addition of the oxygenated AA oxylipin 5-hydroxyeicosatetraenoic acid (5-HETE that is a product of human Alox5. We propose that A. fumigatus acquisition of LoxB (found in few fungi enhances germination rates in polyunsaturated fatty acid-rich environments.

  2. Mutagenic effect of tritated water on spores of Bacillus subtilis

    International Nuclear Information System (INIS)

    Tanooka, H.; Munakata, N.

    1978-01-01

    The mutagenic effect of tritiated water was observed with spores of Bacillus subtilis polA strain suspended in 50 mCi/ml of tritiated water for various intervals. Dose rate given by tritium beta particles to spore core was estimated to be 400 rad/hr from some assumptions and E. coli data computed by Bockrath et al. and Sands et al. The initial mutation rate was 4.2 x 10 -9 mutants/rad, as compared with 2.4 x 10 -9 mutants/rad for 60 Co γ rays and 3.3 x 10 -9 mutants/rad for 30-kVp x rays. The mutagenic effect of tritiated water on spores is most likely due to beta particle ionizing radiation damage

  3. Evolutionary stasis of sporopollenin biochemistry revealed by unaltered Pennsylvanian spores.

    Science.gov (United States)

    Fraser, W T; Scott, A C; Forbes, A E S; Glasspool, I J; Plotnick, R E; Kenig, F; Lomax, B H

    2012-10-01

    The biopolymer sporopollenin present in the spore/pollen walls of all land plants is regarded as one of the most recalcitrant biomacromolecules (biopolymers), providing protection against a range of abiotic stresses. This long-term stability is demonstrated by the near-ubiquitous presence of pollen and spores in the fossil record with spores providing the first evidence for the colonization of the land. Here, we report for the first time chemical analyses of geologically unaltered sporopollenin from Pennsylvanian (c. 310 million yr before present (MyBP)) cave deposits. Our data show that Pennsylvanian Lycophyta megaspore sporopollenin has a strong chemical resemblance to extant relatives and indicates that a co-polymer model of sporopollenin formation is the most likely configuration. Broader comparison indicates that extant sporopollenin structure is similar across widely spaced phylogenetic groups and suggests land plant sporopollenin structure has remained stable since embryophytes invaded land. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  4. The defective phosphoribosyl diphosphate synthase in a temperature-sensitive prs-2 mutant of Escherichia coli is compensated by increased enzyme synthesis

    DEFF Research Database (Denmark)

    Post, David A.; Switzer, Robert L.; Hove-Jensen, Bjarne

    1996-01-01

    An Escherichia coli strain which is temperature-sensitive for growth due to a mutation (prs-2) causing a defective phosphoribosyl diphosphate (PRPP) synthase has been characterized. The temperature-sensitive mutation was mapped to a 276 bp HindIII-BssHII DNA fragment located within the open reading...

  5. Discrimination of Spore-Forming Bacilli Using spoIVA

    Science.gov (United States)

    Venkateswaran, Kasthuri; LaDuc, Myron; Stuecker, Tara

    2009-01-01

    A method of discriminating between spore-forming and non-spore-forming bacteria is based on a combination of simultaneous sporulation-specific and non-sporulation-specific quantitative polymerase chain reactions (Q-PCRs). The method was invented partly in response to the observation that for the purposes of preventing or reducing biological contamination affecting many human endeavors, ultimately, only the spore-forming portions of bacterial populations are the ones that are problematic (or, at least, more problematic than are the non-spore-forming portions). In some environments, spore-forming bacteria constitute small fractions of the total bacterial populations. The use of sporulation-specific primers in Q-PCR affords the ability to assess the spore-forming fraction of a bacterial population present in an environment of interest. This assessment can provide a more thorough and accurate understanding of the bacterial contamination in the environment, thereby making it possible to focus contamination- testing, contamination-prevention, sterilization, and decontamination resources more economically and efficiently. The method includes the use of sporulation-specific primers in the form of designed, optimized deoxyribonucleic acid (DNA) oligonucleotides specific for the bacterial spoIVA gene (see table). [In "spoIVA," "IV" signifies Roman numeral four and the entire quoted name refers to gene A for the fourth stage of sporulation.] These primers are mixed into a PCR cocktail with a given sample of bacterial cells. A control PCR cocktail into which are mixed universal 16S rRNA primers is also prepared. ["16S rRNA" denotes a ribosomal ribonucleic acid (rRNA) sequence that is common to all organisms.] Following several cycles of heating and cooling according to the PCR protocol to amplify amounts of DNA molecules, the amplification products can be analyzed to determine the types of bacterial cells present within the samples. If the amplification product is strong

  6. Effect of synthetic detergents on germination of fern spores

    Energy Technology Data Exchange (ETDEWEB)

    Devi, Y.; Devi, S.

    1986-12-01

    Synthetic detergents constitute one of the most important water pollutants by contaminating the lakes and rivers through domestic and industrial use. Considerable information is now available for the adverse effects of detergents an aquatic fauna including fish, algae, and higher aquatic plants. Marked inhibition of germination in orchids and brinjals and of seedlings growth in raddish suggest that rapidly growing systems could be sensitive to detergent polluted water. The present study of the effect of linear alkyl benzene sulphonate on germination of the spores of a fern, Diplazium esculentum aims at the understanding of the effects of water pollution on pteridophytes and the development of spore germination assay for phytoxicity evaluation.

  7. Architecture and Assembly of the Bacillus subtilis Spore Coat

    Science.gov (United States)

    2014-09-26

    483 489. 15. Abhyankar W, Ter Beek A, Dekker H, Kort R, Brul S, et al. (2011) Gel-free proteomic identification of the Bacillus subtilis insoluble coat... identification of additional sporulation genes in Bacillus subtilis. J Mol Biol 327: 945 972. AFM of Spore Coat Architecture PLOS ONE | www.plosone.org 16 September 2014 | Volume 9 | Issue 9 | e108560 ...1ITLE AND SUBTITLE 5a CONTRACTNUMBER Architecture and assembly of the Bacillus subtilis spore coat W911NF-09-l-0286 5b. GRANT NUMBER 5c. PROGRAM

  8. Physical determinants of radiation sensitivity in bacterial spores

    International Nuclear Information System (INIS)

    Powers, E.L.

    1982-01-01

    Several factors modifying radiation sensitivity in dry bacterial spores are described and discussed. Vacuum inducing the loss of critical structural water, very low dose rates of radiation from which the cell may recover, radiations of high linear energy transfer, and the action of temperature over long periods of time on previously irradiated cells are recognized from extensive laboratory work as important in determining survival of spores exposed to low radiation doses at low temperatures for long periods of time. Some extensions of laboratory work are proposed

  9. Properties of Carry Value Transformation

    Directory of Open Access Journals (Sweden)

    Suryakanta Pal

    2012-01-01

    Full Text Available Carry Value Transformation (CVT is a model of discrete deterministic dynamical system. In the present study, it has been proved that (1 the sum of any two nonnegative integers is the same as the sum of their CVT and XOR values. (2 the number of iterations leading to either CVT=0 or XOR=0 does not exceed the maximum of the lengths of the two addenda expressed as binary strings. A similar process of addition of modified Carry Value Transformation (MCVT and XOR requires a maximum of two iterations for MCVT to be zero. (3 an equivalence relation is shown to exist on Z×Z which divides the CV table into disjoint equivalence classes.

  10. A Novel Spectroscopic Methodology for the Investigation of Individual Bacillus Spores

    National Research Council Canada - National Science Library

    Alexander, Troy A; Pellegrino, Paul; Gillespie, James B

    2005-01-01

    A methodology has been developed for the investigation of bacterial spores. Specifically, this method has been used to probe the spore coat composition of two different Bacillus stearothermophilus variants...

  11. Influence of heat and radiation on the germinability and viability of B. cereus BIS-59 spores

    International Nuclear Information System (INIS)

    Kamat, A.S.; Lewis, N.F.

    1983-01-01

    Spores of Bicillus cereus BIS-59, isolated in this laboratory from shrimps, exhibited an exponential gamma radiation survival curve with a d 10 value of 400 krad as compared with a D 10 value of 30 krad for the vegetative cells. The D 10 value of DPA-depleted spores was also 400 krad indicating that DPA does not influence the radiation response of these spores. Maximum germination monitored with irradiated spores was 60 percent as compared with 80 percent in case of unirradiated spores. Radiation-induced inhibition of the germination processes was not dose dependent. Heat treatment (15 min at 80 C) to spores resulted in activation of the germination process; however, increase in heating time (30 min and 60 min) increased the germination lag period. DPA-depleted spores were less heat resistant than normal spores and exhibited biphasic exponential inactivation. (author)

  12. FORMALDEHYDE GAS INACTIVATION OF BACILLUS ANTHRACIS, BACILLUS SUBTILIS AND GEOBACILLUS STEAROTHERMOPHILUS SPORES ON INDOOR SURFACE MATERIALS.

    Science.gov (United States)

    Research evaluated the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface material using formaldehyde gas. Spores were dried on seven types of indoor surfaces and exposed to 1100 ppm formaldehyde gas for 10 hr. Fo...

  13. Levels of glycine betaine in growing cells and spores of Bacillus species and lack of effect of glycine betaine on dormant spore resistance.

    Science.gov (United States)

    Loshon, Charles A; Wahome, Paul G; Maciejewski, Mark W; Setlow, Peter

    2006-04-01

    Bacteria of various Bacillus species are able to grow in media with very high osmotic strength in part due to the accumulation of low-molecular-weight osmolytes such as glycine betaine (GB). Cells of Bacillus species grown in rich and minimal media contained low levels of GB, but GB levels were 4- to 60-fold higher in cells grown in media with high salt. GB levels in Bacillus subtilis cells grown in minimal medium were increased approximately 7-fold by GB in the medium and 60-fold by GB plus high salt. GB was present in spores of Bacillus species prepared in media with or without high salt but at lower levels than in comparable growing cells. With spores prepared in media with high salt, GB levels were highest in B. subtilis spores and > or =20-fold lower in B. cereus and B. megaterium spores. Although GB levels in B. subtilis spores were elevated 15- to 30-fold by GB plus high salt in sporulation media, GB levels did not affect spore resistance. GB levels were similar in wild-type B. subtilis spores and spores that lacked major small, acid-soluble spore proteins but were much lower in spores that lacked dipicolinic acid.

  14. Optimal spore germination in Clostridium botulinum ATCC 3502 requires the presence of functional copies of SleB and YpeB, but not CwlJ.

    Science.gov (United States)

    Meaney, Carolyn A; Cartman, Stephen T; McClure, Peter J; Minton, Nigel P

    2015-08-01

    Germination, the process by which dormant endospores return to vegetative growth, is a critical process in the life cycle of the notorious pathogen Clostridium botulinum. Crucial is the degradation by hydrolytic enzymes of an inner peptidoglycan spore layer termed the cortex. Two mechanistically different systems of cortex lysis exist in spores of Clostridium species. C. botulinum ATCC 3502 harbours the Bacillus-like system of SleB, CwlJ and YpeB cortex lytic enzymes (CLEs). Through the construction of insertional gene knockout mutants in the sleB, cwlJ and ypeB genes of C. botulinum ATCC 3502 and the production of spores of each mutant strain, the effect on germination was assessed. This study demonstrates a reduced germination efficiency in spores carrying mutations in either sleB or ypeB with an approximate 2-fold reduction in heat resistant colony forming units (CFU/OD600) when plated on rich media. This reduction could be restored to wild-type levels by removing the spore coat and plating on media supplemented with lysozyme. It was observed that cwlJ spores displayed a similar germination efficiency as wild-type spores (P > 0.05). An optimal germinant commixture was identified to include a combination of l-alanine with sodium bicarbonate as it resulted in a 32% drop in OD600, while the additional incorporation of l-lactate resulted in a 57% decrease. Studies of the germination efficiency of spores prepared from all three CLE mutants was performed by monitoring the associated decrease in optical density but a germination defect was not observed in any of the CLE mutant strains. This was likely due to the lack of specificity of this particular assay. Taken together, these data indicate that functional copies of SleB and YpeB, but not CwlJ are required for the optimal germination of the spores of C. botulinum ATCC 3502. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Monitoring Rates and Heterogeneity of High-Pressure Germination of Bacillus Spores by Phase-Contrast Microscopy of Individual Spores

    Science.gov (United States)

    2014-01-01

    processes also have significant applied interest, since (i) spores are major agents of food spoilage and food poisoning and (ii) spores’ extreme...by U N IV O F C O N N E C T IC U T http://aem .asm .org/ D ow nloaded from needed in conjunction with HP to inactivate bacterial spores and...achieve the commercial sterility of low-acid foods (22). While HP is probably most often used as a single treatment, a number of studies have demonstrated

  16. Observations on the migration of bacillus spores outside a contaminated facility during a decontamination efficacy study

    Science.gov (United States)

    Silvestri, Erin E.; Perkins, Sarah; Lordo, Robert; Kovacik, William; Nichols, Tonya L.; Bowling, Charlena Yoder; Griffin, Dale W.; Schaefer, Frank W.

    2015-01-01

    The potential for an intentional wide-area or indoor release of Bacillus anthracis spores remains a concern, but the fate and transport of B. anthracis spores in indoor and outdoor environments are not well understood. Some studies have examined the possibility of spore transport within ventilation systems and in buildings and transport into a building following an outdoor release. Little research exists regarding the potential for spores to migrate to the outside of a building following an indoor release.

  17. Spore germination of fungi belonging to Aspergillus species under deep-sea conditions

    Digital Repository Service at National Institute of Oceanography (India)

    Damare, S.; Nagarajan, M.; Raghukumar, C.

    of fungal spores in the deep sea may face several obstacles like the mycostatic effect of seawater (Kirk, 1980), low temperature, elevated hydrostatic pressure and low nutrient conditions. A defining characteristic of spores is their ability to develop... hyphal colony. The first step in this is the spore germina- tion, which can be defined as the sequence of events that converts the resting/dormant spore into a rapidly growing germ tube from which the myce- lium is produced by elongation, septum formation...

  18. Gene activity during germination of spores of the fern, Onoclea sensibilis. Cell-free translation analysis of mRNA of spores and the effect of alpha-amanitin on spore germination

    Science.gov (United States)

    Raghavan, V.

    1992-01-01

    Poly(A)-RNA fractions of dormant, dark-imbibed (non-germinating) and photoinduced (germinating) spores of Onoclea sensibilis were poor templates in the rabbit reticulocyte lysate protein synthesizing system, but the translational efficiency of poly(A)+RNA was considerably higher than that of unfractionated RNA. Poly(A)+RNA isolated from photoinduced spores had a consistently higher translational efficiency than poly(A)+RNA from dark-imbibed spores. Analysis of the translation products by one-dimensional polyacrylamide gel electrophoresis showed no qualitative differences in the mRNA populations of dormant, dark-imbibed, and photoinduced spores. However, poly(A)+RNA from dark-imbibed spores appeared to encode in vitro fewer detectable polypeptides at a reduced intensity than photoinduced spores. A DNA clone encoding the large subunit of maize ribulose bisphosphate carboxylase hybridized at strong to moderate intensity to RNA isolated from dark-imbibed spores, indicating the absence of mRNA degradation. Although alpha-amanitin did not inhibit the germination of spores, the drug prevented the elongation of the rhizoid and protonemal initial with a concomitant effect on the synthesis of poly(A)+RNA. These results are consistent with the view that some form of translational control involving stored mRNA operates during dark-imbibition and photoinduced germination of spores.

  19. Size matters for violent discharge height and settling speed of Sphagnum spores: important attributes for dispersal potential.

    Science.gov (United States)

    Sundberg, Sebastian

    2010-02-01

    Initial release height and settling speed of diaspores are biologically controlled components which are key to modelling wind dispersal. Most Sphagnum (peat moss) species have explosive spore liberation. In this study, how capsule and spore sizes affect the height to which spores are propelled were measured, and how spore size and spore number of discharged particles relate to settling speed in the aspherical Sphagnum spores. Spore discharge and spore cloud development were filmed in a closed chamber (nine species). Measurements were taken from snapshots at three stages of cloud development. Settling speed of spores (14 species) and clusters were timed in a glass tube. The maximum discharge speed measured was 3.6 m s(-1). Spores reached a maximum height of 20 cm (average: 15 cm) above the capsule. The cloud dimensions at all stages were related positively to capsule size (R(2) = 0.58-0.65). Thus species with large shoots (because they have large capsules) have a dispersal advantage. Half of the spores were released as singles and the rest as clusters (usually two to four spores). Single spores settled at 0.84-1.86 cm s(-1), about 52 % slower than expected for spherical spores with the same diameters. Settling speed displayed a positive curvilinear relationship with spore size, close to predictions by Stokes' law for spherical spores with 68 % of the actual diameters. Light-coloured spores settled slower than dark spores. Settling speed of spore clusters agrees with earlier studies. Effective spore discharge and small, slowly settling spores appear particularly important for species in forested habitats. The spore discharge heights in Sphagnum are among the greatest for small, wind-dispersed propagules. The discharge heights and the slow settling of spores affect dispersal distances positively and may help to explain the wide distribution of most boreal Sphagnum species.

  20. How honey bees carry pollen

    Science.gov (United States)

    Matherne, Marguerite E.; Anyanwu, Gabriel; Leavey, Jennifer K.; Hu, David L.

    2017-11-01

    Honey bees are the tanker of the skies, carrying thirty percent of their weight in pollen per foraging trip using specialized orifices on their body. How do they manage to hang onto those pesky pollen grains? In this experimental study, we investigate the adhesion force of pollen to the honeybee. To affix pollen to themselves, honey bees form a suspension of pollen in nectar, creating a putty-like pollen basket that is skewered by leg hairs. We use tensile tests to show that the viscous force of the pollen basket is more than ten times the honeybee's flight force. This work may provide inspiration for the design of robotic flying pollinators.

  1. Loren Shriver carries Olympic torch

    Science.gov (United States)

    1996-01-01

    KSC Shuttle Operations Manager Loren J. Shriver proudly displays the Olympic torch that he carried to the top of Launch Pad 39A as his contribution to the July 7, 1996 KSC Olympic torch relay effort. Nineteen other KSC runners also participated in the relay effort at the Center. The Olympic torch arrived at KSC at 1:40 p.m. and traveled a 20-mile course to the pad and then out to the KSC visitor Center. The Space Shuttle Atlantis is behind Shriver, poised for the STS-79 mission, which will feature the fourth docking of the Shuttle with the Russian Mir space station.

  2. Induction of prophages in spores of Bacillus subtilis by ultraviolet irradiation from synchrotron orbital radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sadaie, Y.; Kada, T.; Ohta, Y. (National Inst. of Genetics, Mishima, Shizuoka (Japan)); Kobayashi, K.; Hieda, K.; Ito, T.

    1984-06-01

    Prophages were induced from Bacillus subtilis spores lysogenic with SP02 by ultraviolet (160 nm to 240 nm) irradiation from synchrotron orbital radiation (SR UV). SR UV at around 220 nm was most effective in the inactivation of spores and prophage induction from lysogenic spores, suggesting that the lesions are produced on the DNA molecule which eventually induces signals to inactivate the phage repressor.

  3. Anthrax surrogate spores are destroyed by PDT mediated by phenothiazinium dyes

    Science.gov (United States)

    Demidova, Tatiana N.; Hamblin, Michael R.

    2005-04-01

    Some Gram-positive bacteria (including the causative agent of anthrax - Bacillus anthracis) survive conditions of stress and starvation by producing dormant stage spores. The spore"s multilayered capsule consists of inner and outer membranes, cortex, proteinaceous spore coat, and in some species an exosporium. These outer layers enclose dehydrated and condensed DNA, saturated with small, acid-soluble proteins. These protective structures make spores highly resistant to damage by heat, radiation, and commonly employed anti-bacterial agents. Previously Bacillus spores have been shown to be resistant to photodynamic inactivation (PDI) using dyes and light that easily destroy the corresponding vegetative bacteria, but recently we have discovered that they are susceptible to PDI. Photoinactivation, however, is only possible if phenothiazinium dyes are used. Dimethylmethylene blue, methylene blue, new methylene blue and toluidine blue O are all effective photosensitizers. Alternative photosensitizers such as Rose Bengal, polylysine chlorin(e6) conjugate, a tricationic porphyrin and benzoporphyrin derivative are ineffective against spores even though they can easily kill vegetative cells. Spores of B. cereus and B. thuringiensis are most susceptible, B. subtilis and B. atrophaeus are also killed, while B. megaterium is resistant. Photoinactivation is most effective when excess dye is washed from the spores showing that the dye binds to the spores and that excess dye in solution can quench light delivery. The relatively mild conditions needed for spore killing could have applications for treating wounds contaminated by anthrax spores and for which conventional sporicides would have unacceptable tissue toxicity.

  4. Spore-killing meiotic drive factors in a natural population of the fungus Podospora anserina

    NARCIS (Netherlands)

    Gaag, van der M.; Debets, A.J.M.; Oosterhof, J.; Slakhorst, S.M.; Thijssen, J.A.G.M.; Hoekstra, R.F.

    2000-01-01

    In fungi, meiotic drive is observed as spore killing. In the secondarily homothallic ascomycete Podospora anserina it is characterized by the abortion of two of the four spores in the ascus. We have identified seven different types of meiotic drive elements (Spore killers). Among 99 isolates from

  5. SporeWeb : an interactive journey through the complete sporulation cycle of Bacillus subtilis

    NARCIS (Netherlands)

    Eijlander, Robyn T.; Jong, Anne de; Krawczyk, Antonina O.; Holsappel, Siger; Kuipers, Oscar P.

    2014-01-01

    Bacterial spores are a continuous problem for both food-based and health-related industries. Decades of scientific research dedicated towards understanding molecular and gene regulatory aspects of sporulation, spore germination and spore properties have resulted in a wealth of data and information.

  6. DNA capturing machinery through spore-displayed proteins.

    Science.gov (United States)

    Park, T J; Lee, S J; Pan, J-G; Jung, H-C; Park, J Y; Park, J P; Lee, S Y

    2011-10-01

    The purpose of this study was to develop a general method for the facile development of a new DNA biosensor which utilizes streptavidin-displayed spores as a molecular machinery. Fluorescence spectroscopy was used as a monitoring tool for the streptavidin displayed on the surface of Bacillus thuringiensis spores and as a diagnosis method for DNA detection. As a proof-of-concept, four pathogenic bacteria including Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli and Klebsiella pneumonia were used for the detection of pathogenic species. In addition, a set of mutant variants of Wilson's disease were also used for the detection of single nucleotide polymorphism (SNP) in this system. This strategy, utilizing streptavidin-displayed spores, is capable of capturing DNA targets for the detection of pathogenic bacteria and for mutation analysis in Wilson's disease. This approach could be useful as a simple platform for developing sensitive spore-based biosensors for any desired DNA targets in diagnostic applications. © 2011 The Authors. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

  7. Multigeneration Cross-Contamination of Mail with Bacillus anthracis Spores.

    Directory of Open Access Journals (Sweden)

    Jason Edmonds

    Full Text Available The release of biological agents, including those which could be used in biowarfare or bioterrorism in large urban areas, has been a concern for governments for nearly three decades. Previous incidents from Sverdlosk and the postal anthrax attack of 2001 have raised questions on the mechanism of spread of Bacillus anthracis spores as an aerosol or contaminant. Prior studies have demonstrated that Bacillus atrophaeus is easily transferred through simulated mail handing, but no reports have demonstrated this ability with Bacillus anthracis spores, which have morphological differences that may affect adhesion properties between spore and formite. In this study, equipment developed to simulate interactions across three generations of envelopes subjected to tumbling and mixing was used to evaluate the potential for cross-contamination of B. anthracis spores in simulated mail handling. In these experiments, we found that the potential for cross-contamination through letter tumbling from one generation to the next varied between generations while the presence of a fluidizer had no statistical impact on the transfer of material. Likewise, the presence or absence of a fluidizer had no statistically significant impact on cross-contamination levels or reaerosolization from letter opening.

  8. Adhesion of Spores of Bacillus thuringiensis on a Planar Surface

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eunhyea [Georgia Institute of Technology; Kweon, Hyojin [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Lee, Ida [University of Tennessee, Knoxville (UTK); Joy, David Charles [ORNL; Palumbo, Anthony Vito [ORNL; Tsouris, Costas [ORNL

    2010-01-01

    Adhesion of spores of Bacillus thuringiensis (Bt) and spherical silica particles on surfaces was experimentally and theoretically investigated in this study. Topography analysis via atomic force microscopy (AFM) and electron microscopy indicates that Bt spores are rod shaped, {approx}1.3 {mu}m in length and {approx}0.8 {mu}m in diameter. The adhesion force of Bt spores and silica particles on gold-coated glass was measured at various relative humidity (RH) levels by AFM. It was expected that the adhesion force would vary with RH because the individual force components contributing to the adhesion force depend on RH. The adhesion force between a particle and a planar surface in atmospheric environments was modeled as the contribution of three major force components: capillary, van der Waals, and electrostatic interaction forces. Adhesion force measurements for Bt spore (silica particle) and the gold surface system were comparable with calculations. Modeling results show that there is a critical RH value, which depends on the hydrophobicity of the materials involved, below which the water meniscus does not form and the contribution of the capillary force is zero. As RH increases, the van der Waals force decreases while the capillary force increases to a maximum value.

  9. Stem rust spores elicit rapid RPG1 phosphorylation

    Science.gov (United States)

    Stem rust threatens cereal production worldwide. Understanding the mechanism by which durable resistance genes, such as Rpg1, function is critical. We show that the RPG1 protein is phosphorylated within 5 min by exposure to spores from avirulent but not virulent races of stem rust. Transgenic mutant...

  10. Increased resistance of environmental anaerobic spores to inactivation by UV

    NARCIS (Netherlands)

    Hijnen, W.A.M.; Veer, A.J. van der; Beerendonk, E.F.; Medema, Gerriet Jan

    2004-01-01

    Water Company Europoort started a pilot plant (MP)UV study to determine the UV-fluence to meet the Dutch drinking water standards. The results of large volume sampling of this pilot plant demonstrated that environmental spores of sulphite-reducing clostridia (SSRC) were highly resistant against UV.

  11. Changes in spore chemistry and appearance with increasing maturity

    NARCIS (Netherlands)

    Fraser, W.T.; Watson, J.S.; Sephton, M.A.; Lomax, B.H.; Harrington, G.; Gosling, W.D.; Self, S.

    2014-01-01

    Sporopollenin is the primary biopolymer found in the walls of pollen and spores; during maturation sporopollenin undergoes a number of discrete chemical changes, despite maintaining identifiable morphological features which can be exploited for palynological study. Here we report the results of

  12. Decontamination of Bacillus spores adhered to iron and ...

    Science.gov (United States)

    Journal Article This study examines the effectiveness of decontaminating Bacillus globigii spores attached to corroded iron and cement-mortar coupons with free chlorine at two pH levels, monochloramine, chlorine dioxide, ozone, peracetic acid (PAA) and acidified nitrite, followed by flushing.

  13. DNA fingerprinting of spore-forming bacterial isolates, using Bacillus ...

    African Journals Online (AJOL)

    User

    Bc-repetitive extragenic palindromic polymerase chain reaction (Bc-Rep PCR) analysis was conducted on seven Bacillus thuringiensis isolates accessed from the Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ) culture collection and on five local isolates of entomopathogenic spore- forming bacteria.

  14. Biomarkers of Aspergillus spores: Strain typing and protein identification

    Czech Academy of Sciences Publication Activity Database

    Šulc, Miroslav; Pešlová, Kateřina; Žabka, Martin; Hajdúch, M.; Havlíček, Vladimír

    2009-01-01

    Roč. 280, 1-3 (2009), s. 162-168 ISSN 1387-3806 R&D Projects: GA MŠk LC07017; GA ČR GP203/05/P575 Institutional research plan: CEZ:AV0Z50200510 Keywords : aspergillus * spore * protein Subject RIV: EE - Microbiology, Virology Impact factor: 2.117, year: 2009

  15. The proteome of spore surface layers in food spoiling bacteria

    NARCIS (Netherlands)

    Abhyankar, W.R.

    2014-01-01

    Endospores are dormant, multilayered, highly resistant cellular structures formed in response to stress by certain bacteria belonging to the genera Bacillus, Clostridium and other related organisms. In presence of nutrients and favorable conditions spores germinate and grow out as normal vegetative

  16. Spore Proteomics: The Past, Present and the Future

    NARCIS (Netherlands)

    Abhyankar, W.; de Koning, L.J.; Brul, S.; de Koster, C.G.

    2014-01-01

    Endospores are metabolically dormant, multi-layered cellular structures formed by Gram positive bacteria belonging to the genera Bacillus, Clostridium and related organisms. Their external layers are composed of proteins which in part play a role in resistance behaviour of spores to varied chemical

  17. Effects of Ingesting Bacillus Thuringiensis (Berliner) Spores on ...

    African Journals Online (AJOL)

    Bacillus thuringiensis Berliner was isolated from dead Sesamia calamistis Hampson (Lepidoptera: Noctuidae) larvae collected from maize farms in Cape Coast, Ghana. Spores produced from the vegetative cells were incorporated into an artificial diet and fed to 2nd instar S. calamistis larvae. The duration of larval and pupal ...

  18. Effects of Ingesting Bacillus Thuringiensis (Berliner) Spores on ...

    African Journals Online (AJOL)

    Effects of Ingesting Bacillus Thuringiensis (Berliner) Spores on Developmental Stages and Fecundity of Surviving Sesamia Calamistis (Hampson) (Lepidoptera: ... The PDF file you selected should load here if your Web browser has a PDF reader plug-in installed (for example, a recent version of Adobe Acrobat Reader).

  19. Spore survival during batch dry rendering of abattoir waste.

    Science.gov (United States)

    Lowry, P D; Fernando, T; Gill, C O

    1979-01-01

    Normal batch dry rendering practice does not ensure sterile products, because bacterial spores are protected against thermal denaturation by the high fat-low water content environment which results from drying the materials at temperatures below those required for sterilization. PMID:117753

  20. In vitro spore germination and gametophytic growth development of ...

    African Journals Online (AJOL)

    The effects of sucrose, pH and plant growth hormones on spore germination percentage and gametophyte growths of Pteris tripartita were studied. Various morphological structures of gametophytes were observed namely, filamentous, spatulate and heart stages in the MS culture medium with hormones. After 15 days, the ...

  1. DNA fingerprinting of spore-forming bacterial isolates, using Bacillus ...

    African Journals Online (AJOL)

    Bc-repetitive extragenic palindromic polymerase chain reaction (Bc-Rep PCR) analysis was conducted on seven Bacillus thuringiensis isolates accessed from the Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ) culture collection and on five local isolates of entomopathogenic spore-forming bacteria.

  2. Why do dolphins carry sponges?

    Science.gov (United States)

    Mann, Janet; Sargeant, Brooke L; Watson-Capps, Jana J; Gibson, Quincy A; Heithaus, Michael R; Connor, Richard C; Patterson, Eric

    2008-01-01

    Tool use is rare in wild animals, but of widespread interest because of its relationship to animal cognition, social learning and culture. Despite such attention, quantifying the costs and benefits of tool use has been difficult, largely because if tool use occurs, all population members typically exhibit the behavior. In Shark Bay, Australia, only a subset of the bottlenose dolphin population uses marine sponges as tools, providing an opportunity to assess both proximate and ultimate costs and benefits and document patterns of transmission. We compared sponge-carrying (sponger) females to non-sponge-carrying (non-sponger) females and show that spongers were more solitary, spent more time in deep water channel habitats, dived for longer durations, and devoted more time to foraging than non-spongers; and, even with these potential proximate costs, calving success of sponger females was not significantly different from non-spongers. We also show a clear female-bias in the ontogeny of sponging. With a solitary lifestyle, specialization, and high foraging demands, spongers used tools more than any non-human animal. We suggest that the ecological, social, and developmental mechanisms involved likely (1) help explain the high intrapopulation variation in female behaviour, (2) indicate tradeoffs (e.g., time allocation) between ecological and social factors and, (3) constrain the spread of this innovation to primarily vertical transmission.

  3. Why do dolphins carry sponges?

    Directory of Open Access Journals (Sweden)

    Janet Mann

    Full Text Available Tool use is rare in wild animals, but of widespread interest because of its relationship to animal cognition, social learning and culture. Despite such attention, quantifying the costs and benefits of tool use has been difficult, largely because if tool use occurs, all population members typically exhibit the behavior. In Shark Bay, Australia, only a subset of the bottlenose dolphin population uses marine sponges as tools, providing an opportunity to assess both proximate and ultimate costs and benefits and document patterns of transmission. We compared sponge-carrying (sponger females to non-sponge-carrying (non-sponger females and show that spongers were more solitary, spent more time in deep water channel habitats, dived for longer durations, and devoted more time to foraging than non-spongers; and, even with these potential proximate costs, calving success of sponger females was not significantly different from non-spongers. We also show a clear female-bias in the ontogeny of sponging. With a solitary lifestyle, specialization, and high foraging demands, spongers used tools more than any non-human animal. We suggest that the ecological, social, and developmental mechanisms involved likely (1 help explain the high intrapopulation variation in female behaviour, (2 indicate tradeoffs (e.g., time allocation between ecological and social factors and, (3 constrain the spread of this innovation to primarily vertical transmission.

  4. Influence of Heat Shock Temperatures and Fast Freezing on Viability of Probiotic Sporeformers and the Issue of Spore Plate Count Versus True Numbers

    Directory of Open Access Journals (Sweden)

    Mojtaba Jafari

    2016-02-01

    Full Text Available Background and Objectives: The purpose of the present study was to investigate effects of various heat shock conditions and fast freezing and subsequent thawing on the viability and recovery of Bacillus coagulans and Bacillus subtilis as probiotic sporeformers, and also to compare spore plate and microscopic counts. Materials and Methods: After preparing the final suspensions of B. coagulans and Bacillus subtilis subsp. Natto spores, they were spread-plated before and after fast freezing treatment (-70°C for about 1 min. Heat shock treatments of the spores were carried out at 68oC for 15, 20, and 30 min as well as at 80oC for 10 and 15 min. Concentrations of the examined probiotic sporeformers were determined simultaneously by plate enumerations and microscopically determined counts. Student’s t-test and one-way analysis of variance (ANOVA of SPSS were used for statistical analysis of the data. Analysis of DoE results was carried out using Minitab. Results: The results presented here show that the highest recovery rates for B. coagulans (14.75 log CFU/mL and B. subtilis spores (14.80 log CFU/mL were under a heat shock condition of 68°C for 20 min in nutrient agar (p<0.05. In addition, the survival rates of B. coagulans and B. subtilis spores under the fast freezing and subsequent thawing condition were about 90% and 88%, respectively. Plate counts differed significantly from counts determined microscopically, with differences of almost 0.5 and 0.8 log for B. coagulans and B. subtilis spores, respectively (p<0.05. In addition, DoE results of the study revealed that both factors of spore count method and only freezing factor in fast freezing treatment have a significant effect on concentrations of the spores examined (p<0.05. Conclusions: Heat shock conditions, freezing and subsequent thawing circumstances, and plate counts or enumerations determined microscopically have significant influences on the viability of probiotic sporeformers and

  5. Airway inflammation among compost workers exposed to actinomycetes spores

    Directory of Open Access Journals (Sweden)

    Kari Kulvik Heldal

    2015-05-01

    Full Text Available Objectives. To study the associations between exposure to bioaerosols and work-related symptoms, lung function and biomarkers of airway inflammation in compost workers. Materials and method. Personal full-shift exposure measurements were performed on 47 workers employed at five windrow plants (n=20 and five reactor plants (n=27. Samples were analyzed for endotoxins, bacteria, fungal and actinomycetes spores. Health examinations were performed on workers and 37 controls before and after work on the day exposure was measured. The examinations included symptoms recorded by questionnaire, lung function by spirometry and nasal dimensions by acoustic rhinometry (AR. The pneumoproteins CC16, SP-D and SP-A were measured in a blood sample drawn at the end of the day. Results. The levels of endotoxins (median 3 EU/m[sup]3[/sup] , range 0–730 EU/m[sup]3[/sup] and actinomycetes spores (median 0.2 × 10[sup]6[/sup] spores/m[sup]3[/sup] , range 0–590 × 10[sup]6[/sup] spores/m[sup]3[/sup] were significantly higher in reactor plants compared to windrow plants. However, windrow composting workers reported more symptoms than reactor composting workers, probably due to use of respiratory protection. Exposure-response relationships between actinomycetes spores exposure and respiratory effects, found as cough and nose irritation during a shift, was significantly increased (OR 4.3, 95% CI 1.1–16, OR 6.1, 95% CI 1.5–25, respectively, p<0.05 among workers exposed to 0.02–0.3 × 10[sup]6[/sup] actinomycetes spores/m 3 , and FEV1/FVC% decreased cross shift (b=–3.2, SE=1.5%, p<0.01. Effects were weaker in the highest exposed group, but these workers used respiratory protection, frequently limiting their actual exposure. No relationships were found between exposure and pneumoprotein concentrations. Conclusions. The major agent in the aerosol generated at compost plants was actinomycetes spores which was associated with work related cough symptoms and work

  6. NanoSIMS analysis of Bacillus spores for forensics

    Energy Technology Data Exchange (ETDEWEB)

    Weber, P K; Davisson, M L; Velsko, S P

    2010-02-23

    The threat associated with the potential use of radiological, nuclear, chemical and biological materials in terrorist acts has resulted in new fields of forensic science requiring the application of state-of-the-science analytical techniques. Since the anthrax letter attacks in the United States in the fall of 2001, there has been increased interest in physical and chemical characterization of bacterial spores. While molecular methods are powerful tools for identifying genetic differences, other methods may be able to differentiate genetically identical samples based on physical and chemical properties, as well as provide complimentary information, such as methods of production and approximate date of production. Microanalysis has the potential to contribute significantly to microbial forensics. Bacillus spores are highly structured, consisting of a core, cortex, coat, and in some species, an exosporium. This structure provides a template for constraining elemental abundance differences at the nanometer scale. The primary controls on the distribution of major elements in spores are likely structural and physiological. For example, P and Ca are known to be abundant in the spore core because that is where P-rich nucleic acids and Cadipicolinic acid are located, respectively. Trace elements are known to bind to the spore coat but the controls on these elements are less well understood. Elemental distributions and abundances may be directly related to spore production, purification and stabilization methodologies, which are of particular interest for forensic investigation. To this end, we are developing a high-resolution secondary ion mass spectrometry method using a Cameca NanoSIMS 50 to study the distribution and abundance of trace elements in bacterial spores. In this presentation we will review and compare methods for preparing and analyzing samples, as well as review results on the distribution and abundance of elements in bacterial spores. We use NanoSIMS to

  7. Radiosensitivity of spores of Paenibacillus larvae ssp. larvae in honey

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Wanderley Mendes de [Ministerio da Agricultura, Pecuaria e Abastecimento, Rio de Janeiro, RJ (Brazil). Servico de Inspecao de Produtos de Origem Animal]. E-mail: sipa-rj@agricultura.gov.br; Vital, Helio de Carvalho [Centro Tecnologico do Exercito CTEx, Rio de Janeiro, RJ (Brazil). Div. de Defesa Quimica, Biologica e Nuclear]. E-mail: vital@ctex.eb.br; Schuch, Dulce Maria Tocchetto [Ministerio da Agricultura, Pecuaria e Abastecimento, Porto Alegre, RS (Brazil)]. E-mail: micro-lara-rs@agricultura.gov.br

    2007-07-01

    Irradiation, usually used in combination with other conventional methods of conservation, has been proven to be an efficient tool to ensure the safety of many types of foods by destroying pathogenic microorganisms and extending their shelf-lives. This work has investigated the efficacy of gamma irradiation to inactivate spores of the bacterium Paenibacillus larvae that causes the 'American foulbrood', a highly contagious disease still exotic in Brazil that kills bees and contaminates honey, preventing its commercialization and causing great economical losses. In this study, 60 g samples of two types of honey inoculated with 3.5x10{sup 3} spores/mL of that bacterium were irradiated with doses of 0, 5, 7.5, 10, 12.5 and 15 kGy and counted. The analyses indicated a mean reduction of 97.5{+-}0.7% in the number of viable spores exposed to 5 kGy. The application of doses of 7.5 kGy or higher yielded no viable spores above the detection threshold (10/mL). In addition the value of D{sub 10} (3.1{+-}0.3 kGy) was estimated and the logarithm of the population of viable spores of Paenibacillus larvae subsp. larvae was determined as linear and quadratic polynomial functions of the radiation dose. The results indicated that the dose of 10 kGy could be insufficient to assure complete sterilization of honey in some cases while suggesting that 25 kGy would perform such task adequately. (author)

  8. Fighting Ebola through Novel Spore Decontamination Technologies for the Military

    Directory of Open Access Journals (Sweden)

    Christopher J. Doona

    2015-08-01

    Full Text Available AbstractRecently, global public health organizations such as Doctors without Borders (MSF, the World Health Organization (WHO, Public Health Canada, National Institutes of Health (NIH, and the U.S. government developed and deployed Field Decontamination Kits (FDKs, a novel, lightweight, compact, reusable decontamination technology to sterilize Ebola-contaminated medical devices at remote clinical sites lacking infra-structure in crisis-stricken regions of West Africa (medical waste materials are placed in bags and burned. The basis for effectuating sterilization with FDKs is chlorine dioxide (ClO2 produced from a patented invention developed by researchers at the US Army – Natick Soldier RD&E Center (NSRDEC and commercialized as a dry mixed-chemical for bacterial spore decontamination. In fact, the NSRDEC research scientists developed an ensemble of ClO2 technologies designed for different applications in decontaminating fresh produce; food contact and handling surfaces; personal protective equipment; textiles used in clothing, uniforms, tents, and shelters; graywater recycling; airplanes; surgical instruments; and hard surfaces in latrines, laundries, and deployable medical facilities. These examples demonstrate the far-reaching impact, adaptability, and versatility of these innovative technologies. We present herein the unique attributes of NSRDEC’s novel decontamination technologies and a Case Study of the development of FDKs that were deployed in West Africa by international public health organizations to sterilize Ebola-contaminated medical equipment. FDKs use bacterial spores as indicators of sterility. We review the properties and structures of spores and the mechanisms of bacterial spore inactivation by ClO2. We also review mechanisms of bacterial spore inactivation by novel, emerging, and established nonthermal technologies for food preservation, such as high pressure processing, irradiation, cold plasma, and chemical sanitizers

  9. Development of a selective medium for the determination of the spore concentrations of Botrytis cinerea in the air.

    Science.gov (United States)

    Gielen, S; Aerts, R; Seels, B

    2003-01-01

    germination on selective media. From the results of these experiments a correction factor was calculated that will be used when spore concentrations have to be determined for air detections that are carried out in glasshouses.

  10. Low soil moisture during hot periods drives apparent negative temperature sensitivity of soil respiration in a dryland ecosystem: A multi-model comparison

    Science.gov (United States)

    Tucker, Colin; Reed, Sasha C.

    2016-01-01

    Arid and semiarid ecosystems (drylands) may dominate the trajectory of biosphere-to-atmosphere carbon (C) flux over the coming century. Accordingly, understanding dryland CO2 efflux controls is important for understanding C cycling at the global-scale: key unknowns regarding how temperature and moisture interact to regulate dryland C cycling remain. Further, the patchiness of dryland vegetation can create ‘islands of fertility’, with spatially heterogeneous rates of soil respiration (Rs). At our study site in southeastern Utah, USA we added or removed litter (0 to 650% of control) in paired plots that were either associated with a shrub or with interspaces between vascular plants. We measured Rs, soil temperature, and water content (θ) on eight sampling dates between October 2013 and November 2014. Rs was highest following monsoon rains in late summer when soil temperature was ~30°C. During mid-summer, Rs was low, associated with high soil temperatures (>40°C), resulting in an apparent negative temperature sensitivity of Rs at high temperatures, and positive temperature sensitivity at low-moderate temperatures. We used Bayesian statistical methods to compare multiple competing models capturing a wide range of hypothesized relationships between temperature, moisture, and Rs. The best fit model indicates apparent negative temperature sensitivity of soil respiration at high temperatures reflects the control of soil moisture – not high temperatures – in limiting Rs. The modeled Q10 ranged from 2.7 at 5°C to 1.4 at 45°C. Litter addition had no effect on temperature sensitivity or reference respiration (Rref = Rs at 20°C and optimum moisture) beneath shrubs, and little effect on Rref in interspaces, yet Rref was 1.5 times higher beneath shrubs than in interspaces. Together, these results suggest reduced Rs often observed at high temperatures in drylands is dominated by the control of moisture, and that variable litter inputs – at least over the short

  11. Tolerance of spores to ionizing radiation: mechanisms of inactivation, injury and repair

    International Nuclear Information System (INIS)

    Farkas, J.

    1994-01-01

    Radiation resistance of bacterial spores is of great practical importance both in radiation preservation of food and in radiation sterilization of medicine products. This paper attempts to review selected aspects of the effects of ionizing radiation on bacterial spores. It focuses on irradiation in the high-moisture environments that are the usual characteristic of food irradiation, with less emphasis on dry systems in radiation sterilization of medical products. Topics covered include the tolerance of bacterial spores to ionizing radiation, the mechanism of radiation resistance of spores, the effect of environmental factors on radiation resistance, and radiation injury of spores and its consequences. (UK)

  12. Bacteria, mould and yeast spore inactivation studies by scanning electron microscope observations.

    Science.gov (United States)

    Rozali, Siti N M; Milani, Elham A; Deed, Rebecca C; Silva, Filipa V M

    2017-12-18

    Spores are the most resistant form of microbial cells, thus difficult to inactivate. The pathogenic or food spoilage effects of certain spore-forming microorganisms have been the primary basis of sterilization and pasteurization processes. Thermal sterilization is the most common method to inactivate spores present on medical equipment and foods. High pressure processing (HPP) is an emerging and commercial non-thermal food pasteurization technique. Although previous studies demonstrated the effectiveness of thermal and non-thermal spore inactivation, the in-depth mechanisms of spore inactivation are as yet unclear. Live and dead forms of two food spoilage bacteria, a mould and a yeast were examined using scanning electron microscopy before and after the inactivation treatment. Alicyclobacillus acidoterrestris and Geobacillus stearothermophilus bacteria are indicators of acidic foods pasteurization and sterilization processes, respectively. Neosartorya fischeri is a phyto-pathogenic mould attacking fruits. Saccharomyces cerevisiae is a yeast with various applications for winemaking, brewing, baking and the production of biofuel from crops (e.g. sugar cane). Spores of the four microbial species were thermally inactivated. Spores of S. cerevisiae were observed in the ascus and free form after thermal and HPP treatments. Different forms of damage and cell destruction were observed for each microbial spore. Thermal treatment inactivated bacterial spores of A. acidoterrestris and G. stearothermophilus by attacking the inner core of the spore. The heat first altered the membrane permeability allowing the release of intracellular components. Subsequently, hydration of spores, physicochemical modifications of proteins, flattening and formation of indentations occurred, with subsequent spore death. Regarding N. fischeri, thermal inactivation caused cell destruction and leakage of intracellular components. Both thermal and HPP treatments of S. cerevisiae free spores attacked

  13. Stingless bees (Hymenoptera, Meliponini feeding on stinkhorn spores (Fungi, Phallales: robbery or dispersal?

    Directory of Open Access Journals (Sweden)

    Marcio L. Oliveira

    2000-09-01

    Full Text Available Records about stingless bee-fungi interaction are very rare. In Brazilian Amazonia, workers of Trigona crassipes (Fabricius, 1793 and Trigona fulviventris Guérin, 1835 visiting two stinkhorn species, Dictyophora sp. and Phallus sp., respectively, were observed. The workers licked the fungi gleba, a mucilaginous mass of spores covering the pileum. Neither gleba residue nor spores were found on the body surface of these bee workers. These observations indicate that these bee species include spores as a complement in their diet. On the other hand, they also suggest that these stingless bees can, at times, facilitale spore dispersal, in case intact spores are eliminated with the feces.

  14. [Distribution and spatial ordering of biopolymer molecules in resting bacterial spores].

    Science.gov (United States)

    Duda, V I; Korolev, Iu N; El'-Registan, G I; Duzha, M V; Telegin, N L

    1978-01-01

    The presence, distribution and spatial arrangement of biopolymers in situ were studied in both a total intact spore and in a certain cellular layer using a spectroscopic technique of attenuated total refraction (ATR-IR) in the IR region. In contrast to vegetative cells, intact spores were characterized by isotropic distribution of protein components. This feature can be regarded as an index of the cryptobiotic state of spores. However, the distribution of protein components among individual layers of a spore was anisotropic. Bonds characterized by amide I and amide II bands were most often ordered in a layer which comprised cellular structures from the exosporium to the inner spore membrane.

  15. Germination, outgrowth and vegetative growth kinetics of dry heat-treated individual spores ofBacillusspecies.

    Science.gov (United States)

    He, Lin; Chen, Zhan; Wang, Shiwei; Wu, Muying; Setlow, Peter; Li, Yong-Qing

    2018-01-12

    DNA damage kills dry-heated spores of Bacillus subtilis , but dry heat-treatment effects on spore germination and outgrowth have not been studied. This is important, since if dry heat-killed spores germinate and undergo outgrowth, toxic proteins could be synthesized. Here, Raman spectroscopy and differential interference contrast microscopy were used to study germination and outgrowth of individual dry heat-treated B. subtilis and Bacillus megaterium spores. Major findings in this work were as follows. 1) Spores dry heat-treated at 140°C for 20 min nearly all lost viability but retained their Ca 2+ -dipicolinic acid (CaDPA) depot. 2) In most cases, dry heat treatment increased the average times of and variability in all major events in B. subtilis spore germination with nutrient germinants or CaDPA, and one nutrient germination event with B. megaterium spores. 3) B. subtilis spore germination with dodecylamine, which activates spores' CaDPA release channel, was unaffected by dry heat treatment. 4) These results indicate that dry heat treatment likely damages spore proteins important in nutrient germinant recognition and cortex peptidoglycan hydrolysis, but not CaDPA release itself. 5) Analysis of single spores incubated on nutrient-rich agar showed that while dry heat-treated spores that are dead can complete germination, they cannot proceed into outgrowth thus not to vegetative growth. The results of this study provide new information on effects of dry heat on bacterial spores, and indicate that dry heat sterilization regimens should give spores that cannot outgrow and thus cannot synthesize potentially dangerous proteins. IMPORTANCE Much research has shown that high temperature dry heat is a promising means for the inactivation of spores on medical devices and spacecraft decontamination. Dry heat is known to kill Bacillus subtilis spores by DNA damage. However, knowledge about effects of dry heat treatment on spore germination and outgrowth is limited

  16. Effect of essential oils on Aspergillus spore germination, growth and mycotoxin production: a potential source of botanical food preservative.

    Science.gov (United States)

    Gemeda, Negero; Woldeamanuel, Yimtubezinash; Asrat, Daniel; Debella, Asfaw

    2014-05-01

    To investigate effect of essential oils on Aspergillus spore germination, growth and mycotoxin production. In vitro antifungal and antiaflatoxigenic activity of essential oils was carried out using poisoned food techniques, spore germination assay, agar dilution assay, and aflatoxin arresting assay on toxigenic strains of Aspergillus species. Cymbopogon martinii, Foeniculum vulgare and Trachyspermum ammi (T. ammi) essential oils were tested against toxicogenic isolates of Aspergillus species. T. ammi oil showed highest antifungal activity. Absolute mycelial inhibition was recorded at 1 µl/mL by essential oils of T. ammi. The oil also showed, complete inhibition of spore germination at a concentration of 2 µl/mL. In addition, T. ammi oil showed significant antiaflatoxigenic potency by totally inhibiting aflatoxin production from Aspergillus niger and Aspergillus flavus at 0.5 and 0.75 µl/mL, respectively. Cymbopogon martinii, Foeniculum vulgare and T. ammi oils as antifungal were found superior over synthetic preservative. Moreover, a concentration of 5 336.297 µl/kg body weight was recorded for LC50 on mice indicating the low mammalian toxicity and strengthening its traditional reputations. In conclusion, the essential oils from T. ammi can be a potential source of safe natural food preservative for food commodities contamination by storage fungi.

  17. Novelties that change carrying capacity.

    Science.gov (United States)

    Erwin, Douglas H

    2012-09-01

    Comparative developmental studies have revealed a rich array of details about the patterns and processes of morphological change in animals and increasingly in plants. But, applying these insights to the study of major episodes of evolutionary innovation requires understanding how these novel morphologies become established and sufficiently abundant (either as individuals within a species or as a clade of species) to be preserved in the fossil record, and, in many cases, to influence ecological processes. Evolutionary novelties may: (1) disappear without changing the species; (2) be associated with the generation (through selection or drift) of a new species; and if the latter (3) may or may not become ecologically significant. Only the latter are commonly preserved in the fossil record. These alternatives mirror the distinction among historians of technology between innovation and invention. Here, I argue that specific sorts of evolutionary inventions drive ecological transformation, essentially constructing an environment for themselves and ancillary organisms through ecological spillover effects, increasing the "carrying capacity" of an ecosystem. Copyright © 2011 Wiley Periodicals, Inc.

  18. Nanoscale Structural and Mechanical Analysis of Bacillus anthracis Spores Inactivated with Rapid Dry Heating

    Science.gov (United States)

    Felker, Daniel L.; Burggraf, Larry W.

    2014-01-01

    Effective killing of Bacillus anthracis spores is of paramount importance to antibioterrorism, food safety, environmental protection, and the medical device industry. Thus, a deeper understanding of the mechanisms of spore resistance and inactivation is highly desired for developing new strategies or improving the known methods for spore destruction. Previous studies have shown that spore inactivation mechanisms differ considerably depending upon the killing agents, such as heat (wet heat, dry heat), UV, ionizing radiation, and chemicals. It is believed that wet heat kills spores by inactivating critical enzymes, while dry heat kills spores by damaging their DNA. Many studies have focused on the biochemical aspects of spore inactivation by dry heat; few have investigated structural damages and changes in spore mechanical properties. In this study, we have inactivated Bacillus anthracis spores with rapid dry heating and performed nanoscale topographical and mechanical analysis of inactivated spores using atomic force microscopy (AFM). Our results revealed significant changes in spore morphology and nanomechanical properties after heat inactivation. In addition, we also found that these changes were different under different heating conditions that produced similar inactivation probabilities (high temperature for short exposure time versus low temperature for long exposure time). We attributed the differences to the differential thermal and mechanical stresses in the spore. The buildup of internal thermal and mechanical stresses may become prominent only in ultrafast, high-temperature heat inactivation when the experimental timescale is too short for heat-generated vapor to efficiently escape from the spore. Our results thus provide direct, visual evidences of the importance of thermal stresses and heat and mass transfer to spore inactivation by very rapid dry heating. PMID:24375142

  19. The search and identification of the new immunodiagnostic targets of bacillus anthracis spore

    International Nuclear Information System (INIS)

    Biketov, S.; Dunaytsev, I.; Baranova, E.; Marinin, L.; Dyatlov, I.

    2009-01-01

    Spores of Bacillus anthracis have been used as bio warfare agent to bio terrorize purposes. As efficiency of anti-epidemic measures included urgent prevention and treatment is determined by terms within which the bio agent is identified. Direct and rapid spore detection by antibodies based detection system is very attractive alternative to current PCR-based assays or routine phenotyping which are the most accurate but are also complex, time-consumption and expensive. The main difficulty with respect to such kind of anthrax spores detection is a cross-reaction with spores of closely related bacteria. For development of species-specific antibodies to anthrax spores recombinant scFvs or hybridoma technique were used. In both case surface spore antigens contained species-specific epitopes are need. Among exosporium proteins only ExsF(BxpB), ExsK and SoaA are specific to B.cereus group. On the surface of B. anthracis spores, a unique tetrasaccharides containing an novel monosaccharide - anthrose, was discovered. It was shown that anthrose can be serving as species-specific target for B. anthracis spores detection. We have revealed that EA1 isolated from spore of Russians strain STI-1 contain carbohydrate which formed species-specific epitopes and determine immunogenicity of this antigen. Antibodies to this antigen specifically recognized the surface target of B. anthracis spores and do not reacted with others Bacillus spore. Based on these antibodies we developed the test-systems in different formats for rapid direct detection and identification of B. anthracis spores. The results of trial these test-systems with using more than 50 different Bacillus strains were indicated that carbohydrate of EA1 isolated from spore is effective immunodiagnostic target for anthrax spores bio detection.(author)

  20. [Low-temperature responses of enzyme activities related to fiber development of two cotton (Gossvpium hirsutum L.) cultivars with different temperature-sensitivity].

    Science.gov (United States)

    Shu, Hong-mei; Zhou, Zhi-guo; Zheng, Mi; Wang, You-hua

    2009-09-01

    Taking two cotton cultivars with difterent temperature-sensitivity during tneir liner strength formation as test materials, a field experiment of different sowing dates was conducted in Nanjing of Jiangsu Province in 2006 and 2007 to study the effects of low temperature on the activities and gene expression of the enzymes related to fiber development. The low temperature induced by late sowing (with the mean daily minimum temperature being 21.1, 20.5, and 18.1 degrees C during fiber development period) had definite effects on the enzyme activities, and accordingly, the fiber strength formation. Low temperature increased the invertase and beta-1, 3-glucanase activities, decreased the sucrose synthase and sucrose phosphate synthase activities, prolonged the time with higher gene expression level of Expansin and sucrose synthase, and delayed the expression peak and decreased the gene expression quantity of beta-1,3-glucanase. There existed significant differences in the low-temperature responses of related enzymes activities between the two cultivars, with the change ranges of the enzyme activities being larger for temperature-sensitive cultivar Sumian 15 than for temperature-insensitive cultivar Kemian 1, which could be the main reasons leading to the different temnerature-sensitivitv of the two cotton cultivars during their fiber strength formation.

  1. Local temperature-sensitive mechanisms are important mediators of limb tissue hyperemia in the heat-stressed human at rest and during small muscle mass exercise.

    Science.gov (United States)

    Chiesa, Scott T; Trangmar, Steven J; Kalsi, Kameljit K; Rakobowchuk, Mark; Banker, Devendar S; Lotlikar, Makrand D; Ali, Leena; González-Alonso, José

    2015-07-15

    Limb tissue and systemic blood flow increases with heat stress, but the underlying mechanisms remain poorly understood. Here, we tested the hypothesis that heat stress-induced increases in limb tissue perfusion are primarily mediated by local temperature-sensitive mechanisms. Leg and systemic temperatures and hemodynamics were measured at rest and during incremental single-legged knee extensor exercise in 15 males exposed to 1 h of either systemic passive heat-stress with simultaneous cooling of a single leg (n = 8) or isolated leg heating or cooling (n = 7). Systemic heat stress increased core, skin and heated leg blood temperatures (Tb), cardiac output, and heated leg blood flow (LBF; 0.6 ± 0.1 l/min; P 0.05). Increased heated leg deep tissue blood flow was closely related to Tb (R(2) = 0.50; P 0.05), despite unchanged systemic temperatures and hemodynamics. During incremental exercise, heated LBF was consistently maintained ∼ 0.6 l/min higher than that in the cooled leg (P conductance in both legs showing a strong correlation with their respective local Tb (R(2) = 0.85 and 0.95, P < 0.05). We conclude that local temperature-sensitive mechanisms are important mediators in limb tissue perfusion regulation both at rest and during small-muscle mass exercise in hyperthermic humans. Copyright © 2015 the American Physiological Society.

  2. Application of soft heating method using temperature-sensitive ferrite rod for local hyperthermia. Kanon ferrite wo mochiita soft heating ho no hyperthermia eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Matsuki, H. (Tohoku University, Sendai (Japan)); Sato, T. (Fukushima Medical School, Fukushima (Japan)); Murakami, K. (Hachinohe Institute of Technology, Aomori (Japan))

    1991-09-20

    In soft heating method, a kind of hyperthermia, a temperature-sensitive magnetic material is implanted inside body and a deep heating is performed by an induced current using AC magnetic flux. A temperature-sensitive ferrite rod, inserted into a metallic ring (Cu), was prepared as a heating unit having 2mm in diameter and 10mm in length. This unit in the appropriate magnetic field can automatically control temperatures such that the flux is concentrated on the rod and an alternating flux develops heat of the metallic ring at temperatures less or equal to Curie point, the heat of the ring, however, is reduced at temperatures around the Curie point. If the temperature characteristic (saturation temperature is 44 {degree} C) was suitable, a carcinosarcoma was transplanted into the right femoral regions of rats, cultured to grow up to appropriate size. Seven heating operations were performed, for 30 minutes twice a week. The result led to the effect that tumors whose volume were less than 1 cm {sup 3} vanished completely. 19 refs., 12 figs.

  3. [Effects of Nitrogen Fertilization on Soil Respiration and Temperature Sensitivity in Spring Maize Field in Semi-Arid Regions on Loess Plateau].

    Science.gov (United States)

    Jiang, Ji-shao; Guo, Sheng-li; Wang, Rui; Liu, Qing-fang; Wang, Zhi-qi; Zhang, Yan-jun; Li, Na-na; Li, Ru-jian; Wu, De-feng; Sun, Qi-qi

    2015-05-01

    Understanding the effects of nitrogen fertilization on soil respiration rate and its temperature sensitivity (Q10) is of critical importance to predict the variability of soil respiration in cropland. A field experiment was established in a rain-fed spring maize cropland (Zea mays L. ) in the State Key Agro-Ecological Experimental Station in the Loess Plateau in Changwu County, Shaanxi Province, China. The experiment comprised of two treatments: no N-fertilizer application ( CK) and N-fertilizer application with 160 kg N · hm(-2) (N). Soil respiration rate, soil temperature, soil moisture, yields, aboveground biomass and root biomass were measured in two continuous spring maize growing seasons from April 2013 to September 2014. The cumulative soil CO2 emissions were increased by 35% in 2013 and 54% in 2014 in N treatment as compared to CK treatment. Though nitrogen fertilization significantly increased the cumulative soil CO2 emissions (P temperature sensitivity of soil respiration (P soil temperature or moisture. Root biomass was a critical biotical factor for variation of soil respiration under nitrogen fertilization.

  4. 14C Analysis of protein extracts from Bacillus spores.

    Science.gov (United States)

    Cappuccio, Jenny A; Falso, Miranda J Sarachine; Kashgarian, Michaele; Buchholz, Bruce A

    2014-07-01

    Investigators of bioagent incidents or interdicted materials need validated, independent analytical methods that will allow them to distinguish between recently made bioagent samples versus material drawn from the archives of a historical program. Heterotrophic bacteria convert the carbon in their food sources, growth substrate or culture media, into the biomolecules they need. The F(14)C (fraction modern radiocarbon) of a variety of media, Bacillus spores, and separated proteins from Bacillus spores was measured by accelerator mass spectrometry (AMS). AMS precisely measures F(14)C values of biological materials and has been used to date the synthesis of biomaterials over the bomb pulse era (1955 to present). The F(14)C of Bacillus spores reflects the radiocarbon content of the media in which they were grown. In a survey of commercial media we found that the F(14)C value indicated that carbon sources for the media were alive within about a year of the date of manufacture and generally of terrestrial origin. Hence, bacteria and their products can be dated using their (14)C signature. Bacillus spore samples were generated onsite with defined media and carbon free purification and also obtained from archived material. Using mechanical lysis and a variety of washes with carbon free acids and bases, contaminant carbon was removed from soluble proteins to enable accurate (14)C bomb-pulse dating. Since media is contemporary, (14)C bomb-pulse dating of isolated soluble proteins can be used to distinguish between historical archives of bioagents and those produced from recent media. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  5. Characterization of spore laccase from Bacillus subtilis WD23 and ...

    African Journals Online (AJOL)

    The strain was identified as Bacillus subtilis based on its morphological and physiological properties, and 16S rDNA sequence analysis. The optimum pH and temperature for the spore-bound laccase were 6.8 and 60°C, respectively. The temperature half-life of the laccase was 2.5 h at 80°C and 68 h at 60°C. It also showed ...

  6. Antitumor effects and mechanisms of Ganoderma extracts and spores oil

    OpenAIRE

    Chen, Chun; Li, Peng; Li, Ye; Yao, Guan; Xu, Jian-Hua

    2016-01-01

    Ganoderma lucidum is a popular herbal medicine used in China to promote health. Modern studies have disclosed that the active ingredients of Ganoderma can exhibit several effects, including antitumor effects and immunomodulation. The present study evaluated the antitumor effects of self-prepared Ganoderma extracts and spores oil, and investigated the possible underlying mechanisms by observing the effects of the extracts and oil on topoisomerases and the cell cycle. The results showed that Ga...

  7. Fungal spores overwhelm biogenic organic aerosols in a midlatitudinal forest

    Directory of Open Access Journals (Sweden)

    C. Zhu

    2016-06-01

    Full Text Available Both primary biological aerosol particles (PBAPs and oxidation products of biogenic volatile organic compounds (BVOCs contribute significantly to organic aerosols (OAs in forested regions. However, little is known about their relative importance in diurnal timescales. Here, we report biomarkers of PBAP and secondary organic aerosols (SOAs for their diurnal variability in a temperate coniferous forest in Wakayama, Japan. Tracers of fungal spores, trehalose, arabitol and mannitol, showed significantly higher levels in nighttime than daytime (p < 0.05, resulting from the nocturnal sporulation under near-saturated relative humidity. On the contrary, BVOC oxidation products showed higher levels in daytime than nighttime, indicating substantial photochemical SOA formation. Using tracer-based methods, we estimated that fungal spores account for 45 % of organic carbon (OC in nighttime and 22 % in daytime, whereas BVOC oxidation products account for 15 and 19 %, respectively. To our knowledge, we present for the first time highly time-resolved results that fungal spores overwhelmed BVOC oxidation products in contributing to OA especially in nighttime. This study emphasizes the importance of both PBAPs and SOAs in forming forest organic aerosols.

  8. Muricholic acids inhibit Clostridium difficile spore germination and growth.

    Directory of Open Access Journals (Sweden)

    Michael B Francis

    Full Text Available Infections caused by Clostridium difficile have increased steadily over the past several years. While studies on C. difficile virulence and physiology have been hindered, in the past, by lack of genetic approaches and suitable animal models, newly developed technologies and animal models allow these processes to be studied in detail. One such advance is the generation of a mouse-model of C. difficile infection. The development of this system is a major step forward in analyzing the genetic requirements for colonization and infection. While important, it is equally as important in understanding what differences exist between mice and humans. One of these differences is the natural bile acid composition. Bile acid-mediated spore germination is an important step in C. difficile colonization. Mice produce several different bile acids that are not found in humans. These muricholic acids have the potential to impact C. difficile spore germination. Here we find that the three muricholic acids (α-muricholic acid, β-muricholic acid and ω-muricholic acid inhibit C. difficile spore germination and can impact the growth of vegetative cells. These results highlight an important difference between humans and mice and may have an impact on C. difficile virulence in the mouse-model of C. difficile infection.

  9. Sorption of 241Am by Aspergillus niger spore and hyphae

    International Nuclear Information System (INIS)

    Yuanyou Yang; Ning Liu; Jiali Liao; Jiannan Jin; Shunzhong Luo; Taiming Zhang; Pengji Zhao

    2004-01-01

    Biosorption of 241 Am by a fungus A. niger, including the spore and hyphae, was investigated. The preliminary results showed that the adsorption of 241 Am by the microorganism was efficient. More than 96% of the total 241 Am could be removed from 241 Am solutions of 5.6-111 MBq/l (C 0 ) by spore and hyphae of A. niger, with adsorbed 241 Am metal (Q) of 7.2-142.4 MBq/g biomass, and 5.2-106.5 MBq/g, respectively. The biosorption equilibrium was achieved within 1 hour and the optimum pH range was pH 1-3. No obvious effects on 241 Am adsorption by the fungus were observed at 10-45 deg C, or in solutions containing Au 3+ or Ag + , even 2000 times above the 241 Am concentration. The 241 Am biosorption by the fungus obeys the Freundlich adsorption equation. There was no significant difference between the adsorption behavior of A. niger spore and hyphae. (author)

  10. Genetic reconstitution of the human Adenovirus type 2 temperature-sensitive 1 mutant defective in endosomal escape

    Directory of Open Access Journals (Sweden)

    Gastaldelli Michele

    2009-10-01

    Full Text Available Abstract Human Adenoviruses infect the upper and lower respiratory tracts, the urinary and digestive tracts, lymphoid systems and heart, and give rise to epidemic conjunctivitis. More than 51 human serotypes have been identified to-date, and classified into 6 species A-F. The species C Adenoviruses Ad2 and Ad5 (Ad2/5 cause upper and lower respiratory disease, but how viral structure relates to the selection of particular infectious uptake pathways is not known. An adenovirus mutant, Ad2-ts1 had been isolated upon chemical mutagenesis in the past, and shown to have unprocessed capsid proteins. Ad2-ts1 fails to package the viral protease L3/p23, and Ad2-ts1 virions do not efficiently escape from endosomes. It had been suggested that the C22187T point mutation leading to the substitution of the conserved proline 137 to leucine (P137L in the L3/p23 protease was at least in part responsible for this phenotype. To clarify if the C22187T mutation is necessary and sufficient for the Ad2-ts1 phenotype, we sequenced the genes encoding the structural proteins of Ad2-ts1, and confirmed that the Ad2-ts1 DNA carries the point mutation C22187T. Introduction of C22187T to the wild-type Ad2 genome in a bacterial artificial chromosome (Ad2-BAC gave Ad2-BAC46 virions with the full Ad2-ts1 phenotype. Reversion of Ad2-BAC46 gave wild-type Ad2 particles indicating that P137L is necessary and sufficient for the Ad2-ts1 phenotype. The kinetics of Ad2-ts1 uptake into cells were comparable to Ad2 suggesting similar endocytic uptake mechanisms. Surprisingly, infectious Ad2 or Ad5 but not Ad2-ts1 uptake required CALM (clathrin assembly lymphoid myeloid protein, which controls clathrin-mediated endocytosis and membrane transport between endosomes and the trans-Golgi-network. The data show that no other mutations than P137L in the viral protease are necessary to give rise to particles that are defective in capsid processing and endosomal escape. This provides a basis for

  11. The role of heat resistance in thermorestoration of hydrated bacterial spores

    International Nuclear Information System (INIS)

    Friedman, Y.S.; Grecz, N.

    1973-01-01

    This study for the first time presents evidence of the distinct role played in thermorestoration by cellular determinants such as the resistance to heat and radiation, and the ionic state of spores. In the past only radiochemical determinants associated with radical annealment have been studied in hydrated systems. The basic heat resistance of spores plays a significant role in the precipitous drop in spore survival due to 0.45 Mrad radiation plus heat above 65-75 0 C for B.cereus and 75-95 0 C for B.stearothermophilus. The effect of the spores radiation resistance was not distinct except in the frozen state and at the saturation plateau of thermorestoration where the radiation resistant B.cereus showed ca. 1 log cycle higher survival than the radiation sensitive B.stearothermophilus. When spores are chemically converted into their H + and Ca ++ ionic forms, the H + spores are distinctly more responsive than Ca ++ spores to processes of radical annealment responsible for thermorestoration in hydrated spore systems. At temperatures of extensive thermorestoration of water radicals, H + spores showed higher survival than Ca ++ spores. (F.J.)

  12. Morphology and peculiar features of spores of fern species occurring in Poland

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    Elżbieta Zenkteler

    2012-12-01

    Full Text Available The morphology of fern spores collected from natural sites in Poland was examined under light microscopy. Spore samples represented 44 species in 18 genera and in 13 families. Only spores of Ophioglossaceae were obtained from the herbarium of the Adam Mickiewicz University in Poznań while the remaining samples were obtained from living plants. Spore size ranges between 20 to 75 μm and the spores of Osmunda regalis and Polypodium interjectum were found to have remarkably large dimensions. The spores are ellipsoidal, tetrahedral and spherical/globoid in shape. Their apertures are monolete or trilete types. The exine surface patterns are baculate, cristate, granulate, reticulate, tuberculate and verrucate. Pictures of the analyzed spores are collected in a contrasting (size, colour table to make it easier to distinguish between species. The peculiar characters of fern spores are described after a review of major articles concerning the allergenic features of fern spores with special attention to Pteridium aquilinum whose spores and vegetative tissues revealed mutagenic and carcinogenic activity.

  13. Significance of air humidity and air velocity for fungal spore release into the air

    Science.gov (United States)

    Pasanen, A.-L.; Pasanen, P.; Jantunen, M. J.; Kalliokoski, P.

    Our previous field studies have shown that the presence of molds in buildings does not necessarily mean elevated airborne spore counts. Therefore, we investigated the release of fungal spores from cultures of Aspergillus fumigatus, Penicillium sp. and Cladosporium sp. at different air velocities and air humidities. Spores of A. fumigatus and Penicillium sp. were released from conidiophores already at air velocity of 0.5 ms -1, whereas Cladosporium spores required at least a velocity of 1.0 ms -1. Airborne spore counts of A. fumigatus and Penicillium sp. were usually higher in dry than moist air, being minimal at relative humidities (r.h.) above 70%, while the effect of r.h. on the release of Cladosporium sp. was ambivalent. The geometric mean diameter of released spores increased when the r.h. exceeded a certain level which depends on fungal genus. Thus, spores of all three fungi were hygroscopic but the hygroscopicity of various spores appeared at different r.h.-ranges. This study indicates that spore release is controlled by external factors and depends on fungal genus which can be one reason for considerable variation of airborne spore counts in buildings with mold problems.

  14. Bacillus amyloliquefaciens Spore Production Under Solid-State Fermentation of Lignocellulosic Residues.

    Science.gov (United States)

    Berikashvili, Violet; Sokhadze, Kakha; Kachlishvili, Eva; Elisashvili, Vladimir; Chikindas, Michael L

    2017-12-16

    This study was conducted to elucidate cultivation conditions determining Bacillus amyloliquefaciens B-1895 growth and enhanced spore formation during the solid-state fermentation (SSF) of agro-industrial lignocellulosic biomasses. Among the tested growth substrates, corncobs provided the highest yield of spores (47 × 10 10 spores g -1 biomass) while the mushroom spent substrate and sunflower oil mill appeared to be poor growth substrates for spore formation. Maximum spore yield (82 × 10 10 spores g -1 biomass) was achieved when 15 g corncobs were moistened with 60 ml of the optimized nutrient medium containing 10 g peptone, 2 g KH 2 PO 4 , 1 g MgSO 4 ·7H 2 O, and 1 g NaCl per 1 l of distilled water. The cheese whey usage for wetting of lignocellulosic substrate instead water promoted spore formation and increased the spore number to 105 × 10 10 spores g -1 . Addition to the cheese whey of optimized medium components favored sporulation process. The feasibility of developed medium and strategy was shown in scaled up SSF of corncobs in polypropylene bags since yield of 10 × 10 11 spores per gram of dry biomass was achieved. In the SSF of lignocellulose, B. amyloliquefaciens B-1895 secreted comparatively high cellulase and xylanase activities to ensure good growth of the bacterial culture.

  15. Genetic Diversity and Association Characters of Bacteria Isolated from Arbuscular Mycorrhizal Fungal Spore Walls.

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    Gopal Selvakumar

    Full Text Available Association between arbuscular mycorrhizal fungi (AMF and bacteria has long been studied. However, the factors influencing their association in the natural environment is still unknown. This study aimed to isolate bacteria associated with spore walls of AMF and identify their potential characters for association. Spores collected from coastal reclamation land were differentiated based on their morphology and identified by 18S rDNA sequencing as Funneliformis caledonium, Racocetra alborosea and Funneliformis mosseae. Bacteria associated with AMF spore walls were isolated after treating them with disinfection solution at different time intervals. After 0, 10 and 20 min of spore disinfection, 86, 24 and 10 spore associated bacteria (SAB were isolated, respectively. BOX-PCR fingerprinting analysis showed that diverse bacterial communities were associated to AMF spores. Bacteria belonging to the same genera could associate with different AMF spores. Gram positive bacteria were more closely associated with AMF spores. Isolated SAB were characterized and tested for spore association characters such as chitinase, protease, cellulase enzymes and exopolysaccharide production (EPS. Among the 120 SAB, 113 SAB were able to show one or more characters for association and seven SAB did not show any association characters. The 16S rDNA sequence of SAB revealed that bacteria belonging to the phyla Firmicutes, Proteobacteria, Actinobacteria and Bactereiodes were associated with AMF spore walls.

  16. Cold-Adapted Viral Attenuation (CAVA): Highly Temperature Sensitive Polioviruses as Novel Vaccine Strains for a Next Generation Inactivated Poliovirus Vaccine

    Science.gov (United States)

    Sanders, Barbara P.; de los Rios Oakes, Isabel; van Hoek, Vladimir; Bockstal, Viki; Kamphuis, Tobias; Uil, Taco G.; Song, Yutong; Cooper, Gillian; Crawt, Laura E.; Martín, Javier; Zahn, Roland; Lewis, John; Wimmer, Eckard; Custers, Jerome H. H. V.; Schuitemaker, Hanneke; Cello, Jeronimo; Edo-Matas, Diana

    2016-01-01

    The poliovirus vaccine field is moving towards novel vaccination strategies. Withdrawal of the Oral Poliovirus Vaccine and implementation of the conventional Inactivated Poliovirus Vaccine (cIPV) is imminent. Moreover, replacement of the virulent poliovirus strains currently used for cIPV with attenuated strains is preferred. We generated Cold-Adapted Viral Attenuation (CAVA) poliovirus strains by serial passage at low temperature and subsequent genetic engineering, which contain the capsid sequences of cIPV strains combined with a set of mutations identified during cold-adaptation. These viruses displayed a highly temperature sensitive phenotype with no signs of productive infection at 37°C as visualized by electron microscopy. Furthermore, decreases in infectious titers, viral RNA, and protein levels were measured during infection at 37°C, suggesting a block in the viral replication cycle at RNA replication, protein translation, or earlier. However, at 30°C, they could be propagated to high titers (9.4–9.9 Log10TCID50/ml) on the PER.C6 cell culture platform. We identified 14 mutations in the IRES and non-structural regions, which in combination induced the temperature sensitive phenotype, also when transferred to the genomes of other wild-type and attenuated polioviruses. The temperature sensitivity translated to complete absence of neurovirulence in CD155 transgenic mice. Attenuation was also confirmed after extended in vitro passage at small scale using conditions (MOI, cell density, temperature) anticipated for vaccine production. The inability of CAVA strains to replicate at 37°C makes reversion to a neurovirulent phenotype in vivo highly unlikely, therefore, these strains can be considered safe for the manufacture of IPV. The CAVA strains were immunogenic in the Wistar rat potency model for cIPV, inducing high neutralizing antibody titers in a dose-dependent manner in response to D-antigen doses used for cIPV. In combination with the highly productive

  17. Live cell imaging of germination and outgrowth of individual bacillus subtilis spores; the effect of heat stress quantitatively analyzed with SporeTracker.

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    Rachna Pandey

    Full Text Available Spore-forming bacteria are a special problem for the food industry as some of them are able to survive preservation processes. Bacillus spp. spores can remain in a dormant, stress resistant state for a long period of time. Vegetative cells are formed by germination of spores followed by a more extended outgrowth phase. Spore germination and outgrowth progression are often very heterogeneous and therefore, predictions of microbial stability of food products are exceedingly difficult. Mechanistic details of the cause of this heterogeneity are necessary. In order to examine spore heterogeneity we made a novel closed air-containing chamber for live imaging. This chamber was used to analyze Bacillus subtilis spore germination, outgrowth, as well as subsequent vegetative growth. Typically, we examined around 90 starting spores/cells for ≥4 hours per experiment. Image analysis with the purposely built program "SporeTracker" allows for automated data processing from germination to outgrowth and vegetative doubling. In order to check the efficiency of the chamber, growth and division of B. subtilis vegetative cells were monitored. The observed generation times of vegetative cells were comparable to those obtained in well-aerated shake flask cultures. The influence of a heat stress of 85°C for 10 min on germination, outgrowth, and subsequent vegetative growth was investigated in detail. Compared to control samples fewer spores germinated (41.1% less and fewer grew out (48.4% less after the treatment. The heat treatment had a significant influence on the average time to the start of germination (increased and the distribution and average of the duration of germination itself (increased. However, the distribution and the mean outgrowth time and the generation time of vegetative cells, emerging from untreated and thermally injured spores, were similar.

  18. Effects of High Pressure on Bacillus licheniformis Spore Germination and Inactivation.

    Science.gov (United States)

    Borch-Pedersen, Kristina; Mellegård, Hilde; Reineke, Kai; Boysen, Preben; Sevenich, Robert; Lindbäck, Toril; Aspholm, Marina

    2017-07-15

    Bacillus and Clostridium species form spores, which pose a challenge to the food industry due to their ubiquitous nature and extreme resistance. Pressurization at 300 MPa likely triggers germination by opening dipicolinic acid (DPA) channels present in the inner membrane of the spores. In this work, we expose spores of Bacillus licheniformis , a species associated with food spoilage and occasionally with food poisoning, to high pressure (HP) for holding times of up to 2 h. By using mutant spores lacking one or several GRs, we dissect the roles of the GerA, Ynd, and GerK GRs in moderately HP (mHP; 150 MPa)-induced spore germination. We show that Ynd alone is sufficient for efficient mHP-induced spore germination. GerK also triggers germination with mHP, although at a reduced germination rate compared to that of Ynd. GerA stimulates mHP-induced germination but only in the presence of either the intact GerK or Ynd GR. These results suggests that the effectiveness of the individual GRs in mHP-induced germination differs from their effectiveness in nutrient-induced germination, where GerA plays an essential role. In contrast to Bacillus subtilis spores, treatment with very HP (vHP) of 550 MPa at 37°C did not promote effective germination of B. licheniformis spores. However, treatment with vHP in combination with elevated temperatures (60°C) gave a synergistic effect on spore germination and inactivation. Together, these results provide novel insights into how HP affects B. licheniformis spore germination and inactivation and the role of individual GRs in this process. IMPORTANCE Bacterial spores are inherently resistant to food-processing regimes, such as high-temperature short-time pasteurization, and may therefore compromise food durability and safety. The induction of spore germination facilitates subsequent inactivation by gentler processing conditions that maintain the sensory and nutritional qualities of the food. High-pressure (HP) processing is a nonthermal

  19. Data on the experiments of temperature-sensitive hydrogels for pH-sensitive drug release and the characterizations of materials

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2018-04-01

    Full Text Available This article contains experimental data on the strain sweep, the calibration curve of drug (doxorubicin, DOX and the characterizations of materials. Data included are related to the research article “Injectable and body temperature sensitive hydrogels based on chitosan and hyaluronic acid for pH sensitive drug release” (Zhang et al., 2017 [1]. The strain sweep experiments were performed on a rotational rheometer. The calibration curves were obtained by analyzing the absorbance of DOX solutions on a UV–vis-NIR spectrometer. Molecular weight (Mw of the hyaluronic acid (HA and chitosan (CS were determined by gel permeation chromatography (GPC. The deacetylation degree of CS was measured by acid base titration.

  20. Screening mutations of OTOF gene in Chinese patients with auditory neuropathy, including a familial case of temperature-sensitive auditory neuropathy

    Directory of Open Access Journals (Sweden)

    Benedict-Alderfer Cindy

    2010-05-01

    Full Text Available Abstract Background Mutations in OTOF gene, encoding otoferlin, cause DFNB9 deafness and non-syndromic auditory neuropathy (AN. The aim of this study is to identify OTOF mutations in Chinese patients with non-syndromic auditory neuropathy. Methods 73 unrelated Chinese Han patients with AN, including one case of temperature sensitive non-syndromic auditory neuropathy (TS-NSRAN and 92 ethnicity-matched controls with normal hearing were screened. Forty-five pairs of PCR primers were designed to amplify all of the exons and their flanking regions of the OTOF gene. The PCR products were sequenced and analyzed for mutation identification. Results Five novel possibly pathogenic variants (c.1740delC, c.2975_2978delAG, c.1194T>A, c.1780G>A, c.4819C > T were identified in the group of 73 AN patients, in which two novel mutant alleles (c.2975_2978delAG + c.4819C > T were identified in one Chinese TS-NSRAN case. Besides, 10 non-pathogenic variants of the OTOF gene were found in AN patients and controls. Conclusions Screening revealed that mutations in the OTOF gene account for AN in 4 of 73(5.5% sporadic AN patients, which shows a lower genetic load of that gene in contrast to the previous studies based on other populations. Notably, we found two novel mutant alleles related to temperature sensitive non-syndromic auditory neuropathy. This mutation screening study further confirms that the OTOF gene contributes to ANs and to TS-NSRAN.

  1. Sterilization of hydrogen peroxide resistant bacterial spores with stabilized chlorine dioxide.

    Science.gov (United States)

    Friedline, Anthony; Zachariah, Malcolm; Middaugh, Amy; Heiser, Matt; Khanna, Neeraj; Vaishampayan, Parag; Rice, Charles V

    2015-01-01

    Bacillus pumilus SAFR-032 spores isolated from a clean room environment are known to exhibit enhanced resistance to peroxide, desiccation, UV radiation and chemical disinfection than other spore-forming bacteria. The survival of B. pumilus SAFR-032 spores to standard clean room sterilization practices requires development of more stringent disinfection agents. Here, we report the effects of a stabilized chlorine dioxide-based biocidal agent against spores of B. pumilus SAFR-032 and Bacillus subtilis ATCC 6051. Viability was determined via CFU measurement after exposure. Chlorine dioxide demonstrated efficacy towards sterilization of spores of B. pumilus SAFR-032 equivalent or better than exposure to hydrogen peroxide. These results indicate efficacy of chlorine dioxide delivered through a stabilized chlorine dioxide product as a means of sterilization of peroxide- and UV-resistant spores.

  2. Involvement of alanine racemase in germination of Bacillus cereus spores lacking an intact exosporium.

    Science.gov (United States)

    Venir, Elena; Del Torre, Manuela; Cunsolo, Vincenzo; Saletti, Rosaria; Musetti, Rita; Stecchini, Mara Lucia

    2014-02-01

    The L-alanine mediated germination of food isolated Bacillus cereus DSA 1 spores, which lacked an intact exosporium, increased in the presence of D-cycloserine (DCS), which is an alanine racemase (Alr) inhibitor, reflecting the activity of the Alr enzyme, capable of converting L-alanine to the germination inhibitor D-alanine. Proteomic analysis of the alkaline extracts of the spore proteins, which include exosporium and coat proteins, confirmed that Alr was present in the B. cereus DSA 1 spores and matched to that encoded by B. cereus ATCC 14579, whose spore germination was strongly affected by the block of conversion of L- to D-alanine. Unlike ATCC 14579 spores, L-alanine germination of B. cereus DSA 1 spores was not affected by the preincubation with DCS, suggesting a lack of restriction in the reactant accessibility.

  3. The occurrence of Ganoderma spores in the air and its relationships with meteorological factors

    Directory of Open Access Journals (Sweden)

    Agnieszka Grinn-Gofroń

    2012-12-01

    Full Text Available According to a recent study, Ganoderma may be the third genus, after Alternaria and Cladosporium, whose spores cause symptoms of allergy and whose levels are directly related to meteorological factors. There are only few articles from different parts of the world about the relationships between Ganoderma spore count and meteorological factors. The aim of the study was to review all available publications about airborne Ganoderma spores and to compare the results in a short useful form.

  4. Effect of Ultrasonic Waves on the Heat Resistance of Bacillus cereus and Bacillus licheniformis Spores

    Science.gov (United States)

    Burgos, J.; Ordóñez, J. A.; Sala, F.

    1972-01-01

    Heat resistance of Bacillus cereus and Bacillus licheniformis spores in quarter-strength Ringer solution decreases markedly after ultrasonic treatments which are unable to kill a significant proportion of the spore population. This effect does not seem to be caused by a loss of Ca2+ or dipicolinic acid. The use of ultrasonics to eliminate vegetative cells or to break aggregates in Bacillus spore suspensions to be used subsequently in heat resistance experiments appears to be unadvisable. PMID:4627969

  5. A novel method for standardized application of fungal spore coatings for mosquito exposure bioassays.

    Science.gov (United States)

    Farenhorst, Marit; Knols, Bart G J

    2010-01-20

    Interest in the use of fungal entomopathogens against malaria vectors is growing. Fungal spores infect insects via the cuticle and can be applied directly on the insect to evaluate infectivity. For flying insects such as mosquitoes, however, application of fungal suspensions on resting surfaces is more realistic and representative of field settings. For this type of exposure, it is essential to apply specific amounts of fungal spores homogeneously over a surface for testing the effects of fungal dose and exposure time. Contemporary methods such as spraying or brushing spore suspensions onto substrates do not produce the uniformity and consistency that standardized laboratory assays require. Two novel fungus application methods using equipment developed in the paint industry are presented and compared. Wired, stainless steel K-bars were tested and optimized for coating fungal spore suspensions onto paper substrates. Different solvents and substrates were evaluated. Two types of coating techniques were compared, i.e. manual and automated coating. A standardized bioassay set-up was designed for testing coated spores against malaria mosquitoes. K-bar coating provided consistent applications of spore layers onto paper substrates. Viscous Ondina oil formulations were not suitable and significantly reduced spore infectivity. Evaporative Shellsol T solvent dried quickly and resulted in high spore infectivity to mosquitoes. Smooth proofing papers were the most effective substrate and showed higher infectivity than cardboard substrates. Manually and mechanically applied spore coatings showed similar and reproducible effects on mosquito survival. The standardized mosquito exposure bioassay was effective and consistent in measuring effects of fungal dose and exposure time. K-bar coating is a simple and consistent method for applying fungal spore suspensions onto paper substrates and can produce coating layers with accurate effective spore concentrations. The mosquito bioassay

  6. A novel method for standardized application of fungal spore coatings for mosquito exposure bioassays

    Directory of Open Access Journals (Sweden)

    Knols Bart GJ

    2010-01-01

    Full Text Available Abstract Background Interest in the use of fungal entomopathogens against malaria vectors is growing. Fungal spores infect insects via the cuticle and can be applied directly on the insect to evaluate infectivity. For flying insects such as mosquitoes, however, application of fungal suspensions on resting surfaces is more realistic and representative of field settings. For this type of exposure, it is essential to apply specific amounts of fungal spores homogeneously over a surface for testing the effects of fungal dose and exposure time. Contemporary methods such as spraying or brushing spore suspensions onto substrates do not produce the uniformity and consistency that standardized laboratory assays require. Two novel fungus application methods using equipment developed in the paint industry are presented and compared. Methods Wired, stainless steel K-bars were tested and optimized for coating fungal spore suspensions onto paper substrates. Different solvents and substrates were evaluated. Two types of coating techniques were compared, i.e. manual and automated coating. A standardized bioassay set-up was designed for testing coated spores against malaria mosquitoes. Results K-bar coating provided consistent applications of spore layers onto paper substrates. Viscous Ondina oil formulations were not suitable and significantly reduced spore infectivity. Evaporative Shellsol T solvent dried quickly and resulted in high spore infectivity to mosquitoes. Smooth proofing papers were the most effective substrate and showed higher infectivity than cardboard substrates. Manually and mechanically applied spore coatings showed similar and reproducible effects on mosquito survival. The standardized mosquito exposure bioassay was effective and consistent in measuring effects of fungal dose and exposure time. Conclusions K-bar coating is a simple and consistent method for applying fungal spore suspensions onto paper substrates and can produce coating layers

  7. Computer-assisted image processing to detect spores from the fungus Pandora neoaphidis

    OpenAIRE

    Korsnes, Reinert; Westrum, Karin; Fløistad, Erling; Klingen, Ingeborg

    2016-01-01

    This contribution demonstrates an example of experimental automatic image analysis to detect spores prepared on microscope slides derived from trapping. The application is to monitor aerial spore counts of the entomopathogenic fungus Pandora neoaphidis which may serve as a biological control agent for aphids. Automatic detection of such spores can therefore play a role in plant protection. The present approach for such detection is a modification of traditional manual microscopy of prepared s...

  8. Fecundity, spore recruitment and size in Gelidium sesquipedale (Gelidiales,Rhodophyta)

    OpenAIRE

    Santos, R.; Duarte, Pedro

    1996-01-01

    Gelidium sesquipedale fecundity was quantified by counting tetrasporangial sori and cystocarps per meter squared and by estimating the number of spores contained inside them . These were obtained by regression on a size metric of reproductive structures . Tetrasporangial sori length and cystocarp thickness were the best estimators of spore number. To assess spore recruitment, 12 pottery tiles were fixed to the bottom, and the appearance of small fronds was monitored. No clear s...

  9. Neutrophil chemotactic responses induced by fresh and swollen Rhizopus oryzae spores and Aspergillus fumigatus conidia.

    OpenAIRE

    Waldorf, A R; Diamond, R D

    1985-01-01

    With the induction of germination, Rhizopus oryzae spores and Aspergillus fumigatus conidia activate the complement system and induce neutrophil chemotaxis. In contrast, freshly isolated R. oryzae spores did not induce neutrophil migration into lung tissue of mice after intranasal inoculation. Moreover, in microchemotaxis assays neither fresh R. oryzae spores nor A. fumigatus conidia activated sera to stimulate human neutrophil chemotaxis above control migration until at least 10(7) or 10(8) ...

  10. Environmental microbiology as related to planetary quarantine. [water activity and temperature effects on bacterial spore survival

    Science.gov (United States)

    Pflug, I. J.

    1972-01-01

    The survival of Bacillus subtilis var. niger spores suspended in solutions of sucrose and glycerol at calculated water activities and varying temperatures was studied. The overall results indicated that as the water activity of the liquid decreased from .99 to .85, the heat resistance of the spores increased. The nature of the substance controlling the water activity, and the history of the spores prior to treatment also had an affect on their heat resistance.

  11. Parasitized honey bees are less likely to forage and carry less pollen.

    Science.gov (United States)

    Lach, Lori; Kratz, Madlen; Baer, Boris

    2015-09-01

    Research into loss of pollination capacity has focused primarily on documenting pollinator declines and their causes with comparatively little attention paid to how stressors may affect pollinating behavior of surviving pollinators. The European honey bee, Apis mellifera is one of the world's most important generalist pollinators, and Nosema apis is a widespread microsporidian gut parasite of adult A. mellifera. We individually fed 960 newly eclosed A. mellifera workers either a sucrose solution or 400 N. apis spores in a sucrose solution and tagged them with a unique radio frequency identification (RFID) tag to monitor their foraging behavior. We found spore-fed bees were less likely to forage than those fed sugar only. Those that did forage started foraging when they were older and stopped foraging when they were younger than bees fed sugar only. However, inoculated and non-inoculated bees did not significantly differ in the number of foraging trips taken per day, the total hours foraged over their lifetime, or homing ability. Inoculated returning foragers were 4.3 times less likely to be carrying available pollen than non-inoculated returning foragers and the number of pollen grains carried was negatively correlated with the number of N. apis spores. In an arena of artificial flowers, inoculated bees had a tendency (p=0.061) to choose sugar flowers over pollen flowers, compared to non-inoculated bees which visited pollen and sugar flowers equally. These results demonstrate that even a relatively low dose of a widespread disease of A. mellifera may adversely affect bees' ability to pollinate. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Estimation of Available Phosphorus in Soil Using the Population of Arbuscular Mycorrhizal Fungi Spores

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    Machfud Effendy

    2011-09-01

    Full Text Available Soil microbes, such as arbuscular mycorrhizal fungi (AMF have the ability to dissolve unavailable phosphorus (P and they can be used as an indicator of the P availability in soil. The study was conducted on upland soil in East Java. The soil was sampled twice, before and after planting at the harvesting time. The population of AMF spores and soil P availability were observed. The AMF spores were isolated using wet sieving method, decanting, and followed by sucrose density gradient centrifugation. The available P was observed using the Olsen extraction. The numbers of AMF spore was corelated with available P, moreover the numbers of AMF spore was compared to the availabality of P. The results showed that the total number of AMF spores at six sites were ranged from a little to midle, and the available P ranged from low to high level. All soil site samples had a linear corelation between numbers of AMF spore and available P in soil. The greater the number of AMF spore, the higher the available P in soil. It was likely that the availability of P in soil can be predicted by the population of AMF spores in soil. Therefore, the number of AMF spore can be need as a biological method to predict the available P in soil and to make a recommendation the use of P fertilizer.

  13. A highly redundant gene network controls assembly of the outer spore wall in S. cerevisiae.

    Directory of Open Access Journals (Sweden)

    Coney Pei-Chen Lin

    Full Text Available The spore wall of Saccharomyces cerevisiae is a multilaminar extracellular structure that is formed de novo in the course of sporulation. The outer layers of the spore wall provide spores with resistance to a wide variety of environmental stresses. The major components of the outer spore wall are the polysaccharide chitosan and a polymer formed from the di-amino acid dityrosine. Though the synthesis and export pathways for dityrosine have been described, genes directly involved in dityrosine polymerization and incorporation into the spore wall have not been identified. A synthetic gene array approach to identify new genes involved in outer spore wall synthesis revealed an interconnected network influencing dityrosine assembly. This network is highly redundant both for genes of different activities that compensate for the loss of each other and for related genes of overlapping activity. Several of the genes in this network have paralogs in the yeast genome and deletion of entire paralog sets is sufficient to severely reduce dityrosine fluorescence. Solid-state NMR analysis of partially purified outer spore walls identifies a novel component in spore walls from wild type that is absent in some of the paralog set mutants. Localization of gene products identified in the screen reveals an unexpected role for lipid droplets in outer spore wall formation.

  14. Non-Seasonal Variation of Airborne Aspergillus Spore Concentration in a Hospital Building

    Directory of Open Access Journals (Sweden)

    Michael Oberle

    2015-10-01

    Full Text Available Nosocomial fungal infections are gaining increased attention from infectiologists. An adequate investigation into the levels of airborne Aspergillus and other fungal spores in hospital settings, under normal conditions, is largely unknown. We monitored airborne spore contamination in a Swiss hospital building in order to establish a seasonally-dependent base-line level. Air was sampled using an impaction technique, twice weekly, at six different locations over one year. Specimens were seeded in duplicate on Sabouraud agar plates. Grown colonies were identified to genus levels. The airborne Aspergillus spore concentration was constantly low throughout the whole year, at a median level of 2 spores/m3 (inter-quartile range = IQR 1–4, and displayed no seasonal dependency. The median concentration of other fungal spores was higher and showed a distinct seasonal variability with the ambient temperature change during the different seasons: 82 spores/m3 (IQR 26–126 in summer and 9 spores/m3 (IQR 6–15 in winter. The spore concentration varied considerably between the six sampling sites in the building (10 to 26 spores/m3. This variability may explain the variability of study results in the literature.

  15. Bacillus spores and their relevant chemicals studied by terahertz time domain spectroscopy

    Science.gov (United States)

    Tang, Jianhua; Yang, Bin; Llewellyn, Ian; Cutler, Ronald R.; Donnan, Robert S.

    2014-01-01

    Terahertz time domain spectroscopy has been used to investigate 0.2-2.2 THz transmission responses of Bacillus spores and their related chemical components. Whilst no THz signatures could be clearly associated with either sporulated cells or their chief chemical components, differing degrees of signal attenuation and frequency-dependent light scattering were observed depending on spore composition and culture media. The observed monotonic increase in absorption by spores over this THz spectral domain is mainly from Mie scattering and also from remnant water bound to the spores.

  16. Decontamination of B. globigii spores from drinking water infrastructure using disinfectants

    Data.gov (United States)

    U.S. Environmental Protection Agency — Decontamination of Bacillus spores adhered to common drinking water infrastructure surfaces was evaluated using a variety of disinfectants. Corroded iron and...

  17. Two distinct groups within the Bacillus subtilis group display significantly different spore heat resistance properties.

    Science.gov (United States)

    Berendsen, Erwin M; Zwietering, Marcel H; Kuipers, Oscar P; Wells-Bennik, Marjon H J

    2015-02-01

    The survival of bacterial spores after heat treatment and the subsequent germination and outgrowth in a food product can lead to spoilage of the food product and economical losses. Prediction of time-temperature conditions that lead to sufficient inactivation requires access to detailed spore thermal inactivation kinetics of relevant model strains. In this study, the thermal inactivation kinetics of spores of fourteen strains belonging to the Bacillus subtilis group were determined in detail, using both batch heating in capillary tubes and continuous flow heating in a micro heater. The inactivation data were fitted using a log linear model. Based on the spore heat resistance data, two distinct groups (p subtilis group could be identified. One group of strains had spores with an average D120 °C of 0.33 s, while the spores of the other group displayed significantly higher heat resistances, with an average D120 °C of 45.7 s. When comparing spore inactivation data obtained using batch- and continuous flow heating, the z-values were significantly different, hence extrapolation from one system to the other was not justified. This study clearly shows that heat resistances of spores from different strains in the B. subtilis group can vary greatly. Strains can be separated into two groups, to which different spore heat inactivation kinetics apply. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Comparative characterization of silver nanoparticles synthesized by spore extract of Bacillus subtilis and Geobacillus stearothermophilus

    Directory of Open Access Journals (Sweden)

    Seyed Mahdi Ghasemi

    2018-01-01

    Full Text Available Objective(s: Silver nanostructures have gathered remarkable attention due to their applications in diversefields. Researchers have recently demonstrated that bacterial spores are capable of reducing silver ions toelemental silver leading to formation of nanoparticles.Materials and Methods: In this study, spores of Bacillus subtilis and Geobacillus stearothermophilus wereemployed to produce silver nanoparticles (SNPs from silver nitrate (AgNO3 through a green synthesismethod. The production of SNPs by spores, heat inactivated spores (microcapsule and spore extracts wasmonitored and compared at wavelengths between 300 to 700 nm. The biosynthesized SNPs by spore extractswere characterized and confirmed by XRD and TEM analyses.Results: UV-Visible spectroscopy showed that the spore extracts were able to synthesize more SNPs thanthe other forms. The XRD pattern also revealed that the silver nanometals have crystalline structure withvarious topologies. The TEM micrographs showed polydispersed nanocrystal with dimensions ranging from30 to 90 nm and 15 to 50 nm produced by spore extracts of B. subtilis and G. stearothermophilus, respectively.Moreover, these biologically synthesized nanoparticles exhibited antimicrobial activity against differentopportunistic pathogens.Conclusion: This study suggests the bacterial spore extract as a safe, efficient, cost effective and eco-friendlymaterial for biosynthesis of SNPs.

  19. Bacillus subtilis spores PROTECT experiment Space-exposed and Mars-exposed vs. Earth-control

    Data.gov (United States)

    National Aeronautics and Space Administration — Because of their ubiquity and resistance to spacecraft decontamination bacterial spores are considered likely potential forward contaminants on robotic missions to...

  20. Characteristics and determinants of ambient fungal spores in Hualien, Taiwan

    Science.gov (United States)

    Ho, Hsiao-Man; Rao, Carol Y.; Hsu, Hsiao-Hsien; Chiu, Yueh-Hsiu; Liu, Chi-Ming; Chao, H. Jasmine

    Characteristics and determinants of ambient aeroallergens are of much concern in recent years because of the apparent health impacts of allergens. Yet relatively little is known about the complex behaviors of ambient aeroallergens. To address this issue, we monitored ambient fungal spores in Hualien, Taiwan from 1993-1996 to examine the compositions and temporal variations of fungi, and to evaluate possible determinants. We used a Burkard seven-day volumetric spore trap to collect daily fungal spores. Air pollutants, meteorological factors, and Asian dust events were included in the statistical analyses to predict fungal levels. We found that the most dominant fungal categories were ascospores, followed by Cladosporium and Aspergillus/Penicillium. The majority of the fungal categories had significant diurnal and seasonal variations. Total fungi, Cladosporium, Ganoderma, Arthrinium/Papularia, Cercospora, Periconia, Alternaria, Botrytis, and PM 10 had significantly higher concentrations ( p<0.05) during the period affected by Asian dust events. In multiple regression models, we found that temperature was consistently and positively associated with fungal concentrations. Other factors correlated with fungal concentrations included ozone, particulate matters with an aerodynamic diameter less than 10 μm (PM 10), relative humidity, rainfall, atmospheric pressure, total hydrocarbons, carbon monoxide, nitrogen dioxide, and sulfur dioxide. Most of the fungal categories had higher levels in 1994 than in 1995-96, probably due to urbanization of the study area. In this study, we demonstrated complicated interrelationships between fungi and air pollution/meteorological factors. In addition, long-range transport of air pollutants contributed significantly to local aeroallergen levels. Future studies should examine the health impacts of aeroallergens, as well as the synergistic/antagonistic effects of weather, and local and global-scale air pollutions.

  1. Decontamination of carpet exposed to Microsporum canis hairs and spores.

    Science.gov (United States)

    Moriello, Karen A

    2017-04-01

    Objectives The objective of this study was to evaluate the efficacy of vacuuming and three carpet cleaning methods for the removal of Microsporum canis spores and hairs from experimentally contaminated carpets. Methods Sterile Berber carpeting was artificially contaminated with naturally infective M canis hairs and spores. Carpet swatches were vacuumed for 10 s, 30 s and 60 s, and then cultured. Three carpet cleaning methods were evaluated on area rugs experimentally contaminated with infective material: a beater brush carpet shampooing, beater brush carpet shampooing post-disinfectant application and hot water extraction. Home cleaning products labeled as having efficacy against Trichophyton species were used in addition to 1% potassium peroxymonosulfate. Carpets were cultured at 24 h, 48 h and 7 days after cleaning. Good efficacy was no detectable spores at post-cleaning culture. Results All pretreatment carpet samples were culture positive for M canis (>300 colony-forming units [cfu]/site). Vacuuming did not decontaminate carpets but did remove intact hairs. Spores were not detected by wipe samples after two washings with an upright beater brush carpet shampooer or pretreatment with a disinfectant prior to carpet shampooing. Carpets cleaned with one hot water extraction technique had a decrease from 300 cfu/site to a mean of 5.5 cfu/site at 24 and 48 h post-cleaning and 2 cfu/site at day 7. The use of disinfectants was associated with odor, even when dry, and permanent discoloration. Hot water extraction cleaning was associated with the fastest drying time and no discoloration. Conclusions and relevance Carpets exposed to M canis can be disinfected via carpet shampooing or hot water extraction cleaning. Vacuuming of carpets is recommended to remove infective hairs. For homes, exposed carpeting can be decontaminated by routine washing with a carpet shampooer (twice) or hot water extraction. Use of pretreatment with a disinfectant is recommended when a high level

  2. Should women carry their antenatal records?

    OpenAIRE

    Draper, J; Field, S; Thomas, H; Hare, M J

    1986-01-01

    A study of women's views on carrying their medical records during their pregnancy was conducted in Cambridge in 1982. Eighty eight women who were given their full records were compared with a control group of 83 women who carried the traditional cooperation card, both groups answering postal questionnaires about the advantages and disadvantages of carrying their respective records. Most women found advantages in carrying the complete record, although it was too large to carry for practical pu...

  3. Evaluation of Cytotoxicity, Genotoxicity and Hematotoxicity of the Recombinant Spore-Crystal Complexes Cry1Ia, Cry10Aa and Cry1Ba6 from Bacillus thuringiensis in Swiss Mice

    Directory of Open Access Journals (Sweden)

    Ingrid de Souza Freire

    2014-09-01

    Full Text Available The insecticidal properties of Cry-endotoxins from Bacillus thuringiensis (Bt have long been used as spore-crystals in commercial spray formulations for insect control. Recently, some Bt-endotoxin genes have been cloned in many different plants. Toxicological evaluations of three spore-crystal endotoxins, BtCry1Ia, BtCry10Aa and BtCry1Ba6 from B. thuringiensis, were carried out on mice to understand their adverse effects on hematological systems and on genetic material. These three spore-crystals have shown toxic activity to the boll weevil, which is one of the most aggressive pests of the cotton crop. Cry1Ia, Cry10Aa and Cry1Ba6 did not increase the micronucleus frequency in the peripheral erythrocytes of mice and did not cause changes in the frequency of polychromatic erythrocytes. However, some hematologic disburbances were observed, specifically related to Cry1Ia and Cry1Ba6, respectively, for the erythroid and lymphoid lineage. Thus, although the profile of such adverse side effects can be related to their high level of exposure, which is not commonly found in the environment, results showed that these Bt spore-crystals were not harmless to mice, indicating that each spore-crystal endotoxin presents a characteristic profile of toxicity and might be investigated individually.

  4. Influence of food matrix on outgrowth heterogeneity of heat damaged Bacillus cereus spores.

    Science.gov (United States)

    Warda, Alicja K; den Besten, Heidy M W; Sha, Na; Abee, Tjakko; Nierop Groot, Masja N

    2015-05-18

    Spoilage of heat treated foods can be caused by the presence of surviving spore-formers. It is virtually impossible to prevent contamination at the primary production level as spores are ubiquitous present in the environment and can contaminate raw products. As a result spore inactivation treatments are widely used by food producing industries to reduce the microbial spore loads. However consumers prefer mildly processed products that have less impact on its quality and this trend steers industry towards milder preservation treatments. Such treatments may result in damaged instead of inactivated spores, and these spores may germinate, repair, and grow out, possibly leading to quality and safety issues. The ability to repair and grow out is influenced by the properties of the food matrix. In the current communication we studied the outgrowth from heat damaged Bacillus cereus ATCC 14579 spores on Anopore membrane, which allowed following outgrowth heterogeneity of individual spores on broccoli and rice-based media as well as standard and mildly acidified (pH 5.5) meat-based BHI. Rice, broccoli and BHI pH 5.5 media resulted in delayed outgrowth from untreated spores, and increased heterogeneity compared to BHI pH 7.4, with the most pronounced effect in rice media. Exposure to wet heat for 1 min at 95 °C caused 2 log inactivation and approximately 95% of the spores in the surviving fraction were damaged resulting in substantial delay in outgrowth based on the time required to reach a maximum microcolony size of 256 cells. The delay was most pronounced for heat-treated spores on broccoli medium followed by spores on rice media (both untreated and treated). Interestingly, the increase in outgrowth heterogeneity of heat treated spores on BHI pH 7.4 was more pronounced than on rice, broccoli and BHI pH 5.5 conceivably reflecting that conditions in BHI pH 7.4 better support spore damage repair. This study compares the effects of three main factors, namely heat treatment, p

  5. Cytological and proteomic analyses of horsetail (Equisetum arvense L. spore germination

    Directory of Open Access Journals (Sweden)

    Qi eZhao

    2015-06-01

    Full Text Available Spermatophyte pollen tubes and root hairs have been used as single-cell-type model systems to understand the molecular processes underlying polar growth of plant cells. Horsetail (Equisetum arvense L. is a perennial herb species in Equisetopsida, which creates separately growing spring and summer stems in its life cycle. The mature chlorophyllous spores produced from spring stems can germinate without dormancy. Here we report the cellular features and protein expression patterns in five stages of horsetail spore germination (mature spores, rehydrated spores, double-celled spores, germinated spores, and spores with protonemal cells. Using 2-DE combined with mass spectrometry, 80 proteins were found to be abundance changed upon spore germination. Among them, proteins involved in photosynthesis, protein turnover, and energy supply were over-represented. Thirteen proteins appeared as proteoforms on the gels, indicating the potential importance of post-translational modification. In addition, the dynamic changes of ascorbate peroxidase, peroxiredoxin, and dehydroascorbate reductase implied that reactive oxygen species homeostasis is critical in regulating cell division and tip-growth. The diverse expression patterns of proteins in photosynthesis, energy supply, lipid and amino acid metabolism indicated that heterotrophic and autotrophic metabolism were necessary in light-dependent germination of the spores. Twenty-six proteins were involved in protein synthesis and fate, indicating that protein turnover is vital to spore germination. Furthermore, the altered abundance of small G protein Ran, 14-3-3 protein, actin, and Caffeoyl-CoA O-methyltransferase revealed that signaling transduction, vesicle trafficking, cytoskeleton dynamics, and cell wall modulation were critical to cell division and polar growth. These findings lay a foundation toward understanding the molecular mechanisms underlying fern spore asymmetric division and rhizoid polar growth.

  6. Induced Sporicidal Activity of Chlorhexidine against Clostridium difficile Spores under Altered Physical and Chemical Conditions

    Science.gov (United States)

    Nerandzic, Michelle M.; Donskey, Curtis J.

    2015-01-01

    Background Chlorhexidine is a broad-spectrum antimicrobial commonly used to disinfect the skin of patients to reduce the risk of healthcare-associated infections. Because chlorhexidine is not sporicidal, it is not anticipated that it would have an impact on skin contamination with Clostridium difficile, the most important cause of healthcare-associated diarrhea. However, although chlorhexidine is not sporicidal as it is used in healthcare settings, it has been reported to kill spores of Bacillus species under altered physical and chemical conditions that disrupt the spore’s protective barriers (e.g., heat, ultrasonication, alcohol, or elevated pH). Here, we tested the hypothesis that similarly altered physical and chemical conditions result in enhanced sporicidal activity of chlorhexidine against C. difficile spores. Principal Findings C. difficile spores became susceptible to heat killing at 80°C within 15 minutes in the presence of chlorhexidine, as opposed to spores suspended in water which remained viable. The extent to which the spores were reduced was directly proportional to the concentration of chlorhexidine in solution, with no viable spores recovered after 15 minutes of incubation in 0.04%–0.0004% w/v chlorhexidine solutions at 80°C. Reduction of spores exposed to 4% w/v chlorhexidine solutions at moderate temperatures (37°C and 55°C) was enhanced by the presence of 70% ethanol. However, complete elimination of spores was not achieved until 3 hours of incubation at 55°C. Elevating the pH to ≥9.5 significantly enhanced the killing of spores in either aqueous or alcoholic chlorhexidine solutions. Conclusions Physical and chemical conditions that alter the protective barriers of C. difficile spores convey sporicidal activity to chlorhexidine. Further studies are necessary to identify additional agents that may allow chlorhexidine to reach its target within the spore. PMID:25861057

  7. A Clostridium difficile alanine racemase affects spore germination and accommodates serine as a substrate.

    Science.gov (United States)

    Shrestha, Ritu; Lockless, Steve W; Sorg, Joseph A

    2017-06-23

    Clostridium difficile has become one of the most common bacterial pathogens in hospital-acquired infections in the United States. Although C. difficile is strictly anaerobic, it survives in aerobic environments and transmits between hosts via spores. C. difficile spore germination is triggered in response to certain bile acids and glycine. Although glycine is the most effective co-germinant, other amino acids can substitute with varying efficiencies. Of these, l-alanine is an effective co-germinant and is also a germinant for most bacterial spores. Many endospore-forming bacteria embed alanine racemases into their spore coats, and these enzymes are thought to convert the l-alanine germinant into d-alanine, a spore germination inhibitor. Although the C. difficile Alr2 racemase is the sixth most highly expressed gene during C. difficile spore formation, a previous study reported that Alr2 has little to no role in germination of C. difficile spores in rich medium. Here, we hypothesized that Alr2 could affect C. difficile l-alanine-induced spore germination in a defined medium. We found that alr2 mutant spores more readily germinate in response to l-alanine as a co-germinant. Surprisingly, d-alanine also functioned as a co-germinant. Moreover, we found that Alr2 could interconvert l- and d-serine and that Alr2 bound to l- and d-serine with ∼2-fold weaker affinity to that of l- and d-alanine. Finally, we demonstrate that l- and d-serine are also co-germinants for C. difficile spores. These results suggest that C. difficile spores can respond to a diverse set of amino acid co-germinants and reveal that Alr2 can accommodate serine as a substrate. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Role of visible light-activated photocatalyst on the reduction of anthrax spore-induced mortality in mice.

    Directory of Open Access Journals (Sweden)

    Jyh-Hwa Kau

    Full Text Available BACKGROUND: Photocatalysis of titanium dioxide (TiO(2 substrates is primarily induced by ultraviolet light irradiation. Anion-doped TiO(2 substrates were shown to exhibit photocatalytic activities under visible-light illumination, relative environmentally-friendly materials. Their anti-spore activity against Bacillus anthracis, however, remains to be investigated. We evaluated these visible-light activated photocatalysts on the reduction of anthrax spore-induced pathogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Standard plating method was used to determine the inactivation of anthrax spore by visible light-induced photocatalysis. Mouse models were further employed to investigate the suppressive effects of the photocatalysis on anthrax toxin- and spore-mediated mortality. We found that anti-spore activities of visible light illuminated nitrogen- or carbon-doped titania thin films significantly reduced viability of anthrax spores. Even though the spore-killing efficiency is only approximately 25%, our data indicate that spores from photocatalyzed groups but not untreated groups have a less survival rate after macrophage clearance. In addition, the photocatalysis could directly inactivate lethal toxin, the major virulence factor of B. anthracis. In agreement with these results, we found that the photocatalyzed spores have tenfold less potency to induce mortality in mice. These data suggest that the photocatalysis might injury the spores through inactivating spore components. CONCLUSION/SIGNIFICANCE: Photocatalysis induced injuries of the spores might be more important than direct killing of spores to reduce pathogenicity in the host.

  9. Contrasting responses of soil respiration and temperature sensitivity to land use types: Cropland vs. apple orchard on the Chinese Loess Plateau.

    Science.gov (United States)

    Wang, Rui; Sun, Qiqi; Wang, Ying; Zheng, Wei; Yao, Lunguang; Hu, Yaxian; Guo, Shengli

    2018-04-15

    Land use plays an essential role in regional carbon cycling, potentially influencing the exchange rates of CO 2 flux between soil and the atmosphere in terrestrial ecosystems. Temperature sensitivity of soil respiration (Q 10 ), as an efficient parameter to reflect the possible feedback between the global carbon cycle and climate change, has been extensively studied. However, very few reports have assessed the difference in temperature sensitivity of soil respiration under different land use types. In this study, a three-year field experiment was conducted in cropland (winter wheat, Triticum aestivum L.) and apple orchard (Malus domestica Borkh) on the semi-arid Loess Plateau from 2011 to 2013. Soil respiration (measured using Li-Cor 8100), bacterial community structure (represented by 16S rRNA), soil enzyme activities, and soil physicochemical properties of surface soil were monitored. The average annual soil respiration rate in the apple orchard was 12% greater than that in the cropland (2.01 vs. 1.80μmolm -2 s -1 ), despite that the average Q 10 values in the apple orchard was 15% lower than that in the cropland (ranging from 1.63 to 1.41). As to the differences among predominant phyla, Proteobacteria was 26% higher in the apple orchard than that in the cropland, whereas Actinobacteria and Acidobacteria were 18% and 36% lower in the apple orchard. The β-glucosidase and cellobiohydrolase activity were 15% (44.92 vs. 39.09nmolh -1 g -1 ) and 22% greater (21.39 vs. 17.50nmolh -1 g -1 ) in the apple orchard than that in the cropland. Compared to the cropland, the lower Q 10 values in the apple orchard resulted from the variations of bacterial community structure and β-glucosidase and cellobiohydrolase activity. In addition, the lower C: N ratios in the apple orchard (6.50 vs. 8.40) possibly also contributed to its lower Q 10 values. Our findings call for further studies to include the varying effects of land use types into consideration when applying Q 10 values

  10. Energetics of load carrying in Nepalese porters.

    Science.gov (United States)

    Bastien, Guillaume J; Schepens, Bénédicte; Willems, Patrick A; Heglund, Norman C

    2005-06-17

    Nepalese porters routinely carry head-supported loads equal to 100 to 200% of their body weight (Mb) for many days up and down steep mountain footpaths at high altitudes. Previous studies have shown that African women carry head-supported loads of up to 60% of their Mb far more economically than army recruits carrying equivalent loads in backpacks. Here we show that Nepalese porters carry heavier loads even more economically than African women. Female Nepalese porters, for example, carry on average loads that are 10% of their Mb heavier than the maximum loads carried by the African women, yet do so at a 25% smaller metabolic cost.

  11. Self-healing concrete by use of microencapsulated bacterial spores

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J.Y. [Magnel Laboratory for Concrete Research, Faculty of Engineering and Architecture, Ghent University, TechnologieparkZwijnaarde 904, B-9052 Ghent (Belgium); Laboratory of Microbial Ecology and Technology (LabMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Soens, H. [Devan Chemicals NV, Klein Frankrijk 18, 9600 Ronse (Belgium); Verstraete, W. [Laboratory of Microbial Ecology and Technology (LabMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); De Belie, N., E-mail: nele.debelie@ugent.be [Magnel Laboratory for Concrete Research, Faculty of Engineering and Architecture, Ghent University, TechnologieparkZwijnaarde 904, B-9052 Ghent (Belgium)

    2014-02-15

    Microcapsules were applied to encapsulate bacterial spores for self-healing concrete. The viability of encapsulated spores and the influence of microcapsules on mortar specimens were investigated first. Breakage of the microcapsules upon cracking was verified by Scanning Electron Microscopy. Self-healing capacity was evaluated by crack healing ratio and the water permeability. The results indicated that the healing ratio in the specimens with bio-microcapsules was higher (48%–80%) than in those without bacteria (18%–50%). The maximum crack width healed in the specimens of the bacteria series was 970 μm, about 4 times that of the non-bacteria series (max 250 μm). The overall water permeability in the bacteria series was about 10 times lower than that in non-bacteria series. Wet–dry cycles were found to stimulate self-healing in mortar specimens with encapsulated bacteria. No self-healing was observed in all specimens stored at 95%RH, indicating that the presence of liquid water is an essential component for self-healing.

  12. Spore attachment and extracellular mucilage of aquatic hyphomycetes.

    Science.gov (United States)

    Au, D W; Jones, E B; Moss, S T

    1996-01-01

    Stages in conidiun attachment to surfaces of Lemmoniera aquatica and Mycocentrospora filiformis (freshwater Hyphomycetes) were studied at the light microscope and scanning and transmission electron microscope levels. Sigmoid conidia of M. filiformis attach by pre-existing conidial mucilage at the spore pole and at a point along the conidial body. Tetraradiate conidia of L. aquatica attach by the thigmotropic release of mucilage at the tips of the three "arms";. Germination in both species is followed by the production of germ tubes, germ hyphae and appressoria. The chemical composition of the mucilage involved in attachment was determined by enzymatic studies and lectin-gold cytochemical studies. The major component was found to be acidic poly-saccharide, comprising mainly ß-1, 3-glucan, N-acetyl-D-glucosamine and N-acetyl-neuraminic acid. Variation in mucilage composition exists between the two species, among different structures of the same species, and on different regions of the same structure. This indicates that mucilage producton in the two species is a dynamic process.The ability to secure rapid spore attachment, often in turbulent condition, would be a competitive advantage to these saprobic fungi in the colonization of substrata.

  13. Identifying and quantifying Phakopsora pachyrhizi spores in rain.

    Science.gov (United States)

    Barnes, C W; Szabo, L J; Bowersox, V C

    2009-04-01

    In summers of 2005 and 2006, rain was collected weekly at over 100 selected National Atmospheric Deposition Program/National Trends Network sites across the soybean-growing region of the central and eastern United States. Rain samples were screened for Phakopsora pachyrhizi (causal agent of soybean rust) DNA using a nested real-time polymerase chain reaction assay. Over this time frame, P. pachyrhizi spores were detected in every state in the study, but more frequently in states along the Gulf and Atlantic coasts and along the Ohio River Valley westward to Kansas. A bimodal temporal distribution of samples testing positive for P. pachyrhizi was found in both years. However, there was a greater than threefold increase in the number of samples testing positive for P. pachyrhizi in 2006 compared with 2005, with the most significant increase in August. There was also an increase in the average number of spores per sample in 2006 relative to 2005. Sequence analysis of a subset of positive samples was used to validate the assay results. From the sequence analysis, two reliable polymorphic regions were found, resulting in six distinct genotypes. One genotype was found in 56% of the samples tested, whereas the other genotypes were found less frequently.

  14. Assessment of mould spore exposure and relations to symptoms in wood trimmers

    NARCIS (Netherlands)

    Eduard, W.

    1993-01-01

    Relationships between exposure to mould spores, IgG antibodies against moulds and respiratory and febrile symptoms were studied among wood trimmers. A new method for quantitative assessment of mould spore exposure by scanning electron microscopy was developed. This method was validated by

  15. Distribution of mycorrhizal fungal spores in soils under agroforestry and monocultural coffee systems in Brazil

    NARCIS (Netherlands)

    Cardoso, I.M.; Boddington, C.L.; Janssen, B.H.; Oenema, O.; Kuyper, T.W.

    2003-01-01

    Deep-rooting trees in agroforestry systems may promote distribution of spores of arbuscular mycorrhizal fungi (AMF) at deeper soil levels. We investigated the vertical distribution of AMF spores in Oxisols under agroforestry and monocultural (unshaded) coffee systems in on-farm experiments (

  16. Bringing Evolution to a Technological Generation: A Case Study with the Video Game SPORE

    Science.gov (United States)

    Poli, DorothyBelle; Berenotto, Christopher; Blankenship, Sara; Piatkowski, Bryan; Bader, Geoffrey A.; Poore, Mark

    2012-01-01

    The video game SPORE was found to hold characteristics that stimulate higher-order thinking even though it rated poorly for accurate science. Interested in evaluating whether a scientifically inaccurate video game could be used effectively, we exposed students to SPORE during an evolution course. Students that played the game reported that they…

  17. Mutation Induction with UV- and X-radiations in spores and vegetative cells of Bacillus subtilis

    International Nuclear Information System (INIS)

    Tanooka, H.; Munakata, N.; Kitahara, S.

    1978-01-01

    Spores and vegetative cells of Bacillus subtilis strains with various defects in DNA-repair capacities (hcr - , ssp - , hcr - ssp - ) were irradiated with UV radiation or X-rays. Induced mutation frequency was determined from the observed frequency of prototrophic reversion of a suppressible auxotropic mutation. At equal physical dose, after either UV- or X-irradiation, spores were more resistant to mutations as well as to killing than were vegetative cells. However, quantitative comparison revealed that, at equally lethal doses, spores and vegetative cells were almost equally mutable by X-rays whereas spores were considerably less mutable by UV than were vegetative cells. Thus, as judged from their mutagenic efficiency relative to the lethality, X-ray-induced damage in the spore DNA and the vegetative DNA were equally mutagenic, while UV-induced DNA photoproducts in the spore were less mutagenic than those in vegetative cells. Post-treatment of UV-irradiated cells with caffeine decreased the survival and the induced mutation frequency for either spores or vegetative cells for all the strains. In X-irradiated spores however, a similar suppressing effect of caffeine was observed only for mutability of a strain lacking DNA polymerase I activity

  18. Removal of Bacillus anthracis sterne spore from commercial unpasteurized liquid egg white using crossflow microfiltration

    Science.gov (United States)

    Current pasteurization technology used by the egg industry is ineffective for destruction of spores such as those of Bacillus anthracis (BA). The validity of a cross-flow microfiltration (MF) process for separation of the attenuated strain of BA (Sterne) spores from commercial unpasteurized liquid ...

  19. Spore dispersal of fetid Lysurus mokusin by feces of mycophagous insects.

    Science.gov (United States)

    Chen, Gao; Zhang, Rui-Rui; Liu, Yang; Sun, Wei-Bang

    2014-08-01

    The ecological roles and biological mechanisms of zoochory in plants have long been foci in studies of co-evolutionary processes between plants and animals. However, the dispersal of fungal spores by animals has received comparatively little attention. In this study, the dispersal of spores of a selected fetid fungus, Lysurus mokusin, via feces of mycophagous insects was explored by: collecting volatiles emitted by the fungus using dynamic headspace extraction and analyzing them by GC-MS; testing the capacity of mycophagous insects to disperse its spores by counting spores in their feces; comparing the germinability of L. mokusin spores extracted from feces of nocturnal earwigs and natural gleba of the fungus; and assessing the ability of L. mokusin volatiles to attract insects in bioassays with synthetic scent mixtures. Numerous spores were detected in insects' feces, the bioassays indicated that L. mokusin odor (similar to that of decaying substances) attracts diverse generalist mycophagous insects, and passage through the gut of Anisolabis maritima earwigs significantly enhanced the germination rate of L. mokusin spores. Therefore, nocturnal earwigs and diurnal flies probably play important roles in dispersal of L. mokusin spores, and dispersal via feces may be an important common dispersal mechanism for fungal reproductive tissue.

  20. Optimization of Spore Forming Bacteria Flooding for Enhanced Oil Recovery in North Sea Chalk Reservoir

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Nielsen, Sidsel Marie; Eliasson Lantz, Anna

    2015-01-01

    was used for this purpose. A spore forming bacterium, Bacillus licheniformis 421, was used as it was shown to be a good candidate in the previous study. Bacterial spore can penetrate deeper into the chalk rock, squeezing through the pore throats. Our results show that B. licheniformis 421 when injected...

  1. Reduction of Clostridium sporogenes spore outgrowth in natural sausage casings using nisin.

    Science.gov (United States)

    Wijnker, J J; Weerts, E A W S; Breukink, E J; Houben, J H; Lipman, L J A

    2011-08-01

    Preservation of natural sausage casings using dry salt or saturated brine is regarded as sufficient to inactivate vegetative pathogenic non-spore-forming bacteria present on the casings. Although the outgrowth of bacterial spores is prevented by salt or saturated brine preservation, these spores will remain present and develop into vegetative cells when conditions are more favourable. To prevent subsequent outgrowth additional preservation measures should be implemented. In the experiments described the use of nisin was evaluated to reduce outgrowth of spores in desalinated casings. The bacteriocin nisin was chosen because of its known efficacy against spore-forming bacteria and their spores in various foodstuffs. Clostridium spore suspensions (Clostridium sporogenes, ATCC 3584) were used in two concentrations to inoculate three nisin concentrations (10, 50, 100 μg/mL) in water containing gamma-irradiated casings. Additionally, the binding of nisin to casings, using (14)C-labeled nisin Z and subsequent availability of nisin were evaluated. Results demonstrate that nisin is partly reversibly bound to casings and can reduce the outgrowth of Clostridium spores in the model used by approximately 1 log(10) (90%). However, the biological relevance of these results needs to be determined further by conducting industrial trials before any recommendation can be made on the practical implementation of nisin in the preservation of natural sausage casings. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Felling Infected Oaks in Natural Stands Reduces Dissemination of Polyporus Hispidus Spores

    Science.gov (United States)

    E. R. Toole; F. I. McCracken

    1974-01-01

    Felling or girdling willow oaks which exhibited Polyporus hispidus cankers reduced sporophore production within 3 yr. Since spore dissemination was horizontal and downward, spores produced on felled trees did not spread as far as those from standing trees. Felling, therefore, is a more advantageous means of control.

  3. Analysis of germination and outgrowth of sorbic acid-stressed Bacillus cereus ATCC 14579 spores.

    NARCIS (Netherlands)

    Melis, van Clint; Nierop Groot, Masja; Tempelaars, Marcel; Moezelaar, Roy; Abee, Tjakko

    2010-01-01

    Sorbic acid (SA) is widely used as a preservative, but the effect of SA on spore germination and outgrowth has gained limited attention up to now. Therefore, the effect of sorbic acid on germination of spores of B. cereus strain ATCC 14579 was analyzed both at phenotype and transcriptome level.

  4. Changes in concentration of Alternaria and Cladosporium spores during summer storms

    Science.gov (United States)

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2013-09-01

    Fungal spores are known to cause allergic sensitization. Recent studies reported a strong association between asthma symptoms and thunderstorms that could be explained by an increase in airborne fungal spore concentrations. Just before and during thunderstorms the values of meteorological parameters rapidly change. Therefore, the goal of this study was to create a predictive model for hourly concentrations of atmospheric Alternaria and Cladosporium spores on days with summer storms in Szczecin (Poland) based on meteorological conditions. For this study we have chosen all days of June, July and August (2004-2009) with convective thunderstorms. There were statistically significant relationships between spore concentration and meteorological parameters: positive for air temperature and ozone content while negative for relative humidity. In general, before a thunderstorm, air temperature and ozone concentration increased, which was accompanied by a considerable increase in spore concentration. During and after a storm, relative humidity increased while both air temperature ozone concentration along with spore concentrations decreased. Artificial neural networks (ANN) were used to assess forecasting possibilities. Good performance of ANN models in this study suggest that it is possible to predict spore concentrations from meteorological variables 2 h in advance and, thus, warn people with spore-related asthma symptoms about the increasing abundance of airborne fungi on days with storms.

  5. A probabilistic modeling approach in thermal inactivation: estimation of postprocess Bacillus cereus spore prevalence and concentration

    NARCIS (Netherlands)

    Membre, J.M.; Amezquita, A.; Bassett, J.; Giavedoni, P.; Blackburn, W.; Gorris, L.G.M.

    2006-01-01

    The survival of spore-forming bacteria is linked to the safety and stability of refrigerated processed foods of extended durability (REPFEDs). A probabilistic modeling approach was used to assess the prevalence and concentration of Bacillus cereus spores surviving heat treatment for a semiliquid

  6. Evaluating the transport of bacillus subtilis spores as a potential surrogate for Cryptosporidium parvum Oocysts

    Science.gov (United States)

    The USEPA has recommended the use of aerobic spores as an indicator for Cryptosporidium oocysts when determining groundwater under the direct influence of surface water. Surface properties, interaction energies, transport, retention, and release behavior of B. subtilis spores were measured over a r...

  7. Germinant-enhanced decontamination of Bacillus spores adhered to iron and cement-mortar drinking water infrastructures.

    Science.gov (United States)

    Szabo, Jeffrey G; Muhammad, Nur; Heckman, Lee; Rice, Eugene W; Hall, John

    2012-04-01

    Germination was evaluated as an enhancement to decontamination methods for removing Bacillus spores from drinking water infrastructure. Germinating spores before chlorinating cement mortar or flushing corroded iron was more effective than chlorinating or flushing alone.

  8. DECONTAMINATION ASSESSMENT OF BACILLUS ANTHRACIS, BACILLUS SUBTILIS, AND GEOBACILLUS STEAROTHERMOPHILUS SPORES ON INDOOR SURFACTS USING A HYDROGEN PERIOXIDE GAS GENERATOR

    Science.gov (United States)

    Aims: To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using hydrogen peroxide gas. Methods and Results: B. anthracis, B. subtilis, and G. Stearothermophilus spores were dried on seven...

  9. A temperature-sensitive allele of a putative mRNA splicing helicase down-regulates many cell wall genes and causes radial swelling in Arabidopsis thaliana.

    Science.gov (United States)

    Howles, Paul A; Gebbie, Leigh K; Collings, David A; Varsani, Arvind; Broad, Ronan C; Ohms, Stephen; Birch, Rosemary J; Cork, Ann H; Arioli, Tony; Williamson, Richard E

    2016-05-01

    The putative RNA helicase encoded by the Arabidopsis gene At1g32490 is a homolog of the yeast splicing RNA helicases Prp2 and Prp22. We isolated a temperature-sensitive allele (rsw12) of the gene in a screen for root radial swelling mutants. Plants containing this allele grown at the restrictive temperature showed weak radial swelling, were stunted with reduced root elongation, and contained reduced levels of cellulose. The role of the protein was further explored by microarray analysis. By using both fold change cutoffs and a weighted gene coexpression network analysis (WGCNA) to investigate coexpression of genes, we found that the radial swelling phenotype was not linked to genes usually associated with primary cell wall biosynthesis. Instead, the mutation has strong effects on expression of secondary cell wall related genes. Many genes potentially associated with secondary walls were present in the most significant WGCNA module, as were genes coding for arabinogalactans and proteins with GPI anchors. The proportion of up-regulated genes that possess introns in rsw12 was above that expected if splicing was unrelated to the activity of the RNA helicase, suggesting that the helicase does indeed play a role in splicing in Arabidopsis. The phenotype may be due to a change in the expression of one or more genes coding for cell wall proteins.

  10. Establishment and functional characterization of a tracheal epithelial cell line RTEC11 from transgenic rats harboring temperature-sensitive simian virus 40 large T-antigen.

    Science.gov (United States)

    Tabuchi, Yoshiaki; Doi, Takeshi; Takasaki, Ichiro; Takahashi, Ri-ichi; Ueda, Masatsugu; Suzuki, Yoshihisa; Obinata, Masuo

    2008-11-01

    A tracheal epithelial cell line RTEC11 was established from transgenic rats harboring temperature-sensitive simian virus 40 large T-antigen. The cells grew continuously at a permissive temperature of 33 degrees C but not at a non-permissive temperature of 39 degrees C. Morphological and functional investigations demonstrated that the cells were polarized epithelial cells maintaining a regulated permeability barrier function. Interestingly, the expression levels of Muc1 (mucin 1) and Scgb1a1 (uteroglobin), non-ciliated secretory cell markers, and Tubb4 (tubulin beta 4), a ciliated cell marker, were significantly increased under the cell growth-restricted condition. Global gene expression and computational network analyses demonstrated a significant genetic network associated with cellular development and differentiation in cells cultured at the non-permissive temperature. The tracheal epithelial cell line RTEC11 with unique characteristics should be useful as an in vitro model for studies of the physiological functions and gene expression of tracheal epithelial cells.

  11. Genes involved in nonpermissive temperature-induced cell differentiation in Sertoli TTE3 cells bearing temperature-sensitive simian virus 40 large T-antigen

    International Nuclear Information System (INIS)

    Tabuchi, Yoshiaki; Kondo, Takashi; Suzuki, Yoshihisa; Obinata, Masuo

    2005-01-01

    Sertoli TTE3 cells, derived from transgenic mice bearing temperature-sensitive simian virus 40 large T (tsSV40LT)-antigen, proliferated continuously at a permissive temperature (33 deg C) whereas inactivation of the large T-antigen by a nonpermissive temperature (39 deg C) led to differentiation as judged by elevation of transferrin. To clarify the detailed mechanisms of differentiation, we investigated the time course of changes in gene expression using cDNA microarrays. Of the 865 genes analyzed, 14 genes showed increased levels of expression. Real-time quantitative PCR revealed that the mRNA levels of p21 waf1 , milk fat globule membrane protein E8, heat-responsive protein 12, and selenoprotein P were markedly elevated. Moreover, the differentiated condition induced by the nonpermissive temperature significantly increased mRNA levels of these four genes in several cell lines from the transgenic mice bearing the oncogene. The present results regarding changes in gene expression will provide a basis for a further understanding of molecular mechanisms of differentiation in both Sertoli cells and cell lines transformed by tsSV40LT-antigen

  12. Yeast screens for host factors in positive-strand RNA virus replication based on a library of temperature-sensitive mutants.

    Science.gov (United States)

    Nawaz-ul-Rehman, Muhammad Shah; Reddisiva Prasanth, K; Baker, Jannine; Nagy, Peter D

    2013-02-01

    RNA viruses exploit host cells by altering cellular pathways, recruiting host factors, remodeling intracellular membranes and escaping host antiviral responses. Model hosts, such as Saccharomyces cerevisiae (yeast), are valuable to identify host factors involved in viral RNA replication. The many advantages of using yeast include the availability of various yeast mutant libraries, such as (i) single gene-deletion library; (ii) the essential gene library (yTHC); and (iii) the yeast ORF over-expression library. Here, we have used a novel temperature-sensitive (ts) mutant library of essential yeast genes to identify 118 host proteins affecting replication of Tomato bushy stunt virus, in yeast model host. Testing 787 ts mutants led to the identification of host factors, of which 72 proteins facilitated TBSV replication in yeast and 46 proteins were inhibitory. Altogether, ~85% of the identified proteins are novel host factors affecting tombusvirus replication. The ts mutant library screen also led to the identification of 17 essential genes, which have been documented before, thus confirming the importance of these genomic screens. Overall, we show the power of ts mutant library in identification of host factors for RNA virus replication. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Local Dynamic Stability Associated with Load Carrying

    Directory of Open Access Journals (Sweden)

    Jian Liu

    2013-03-01

    Conclusion: Current study confirmed the sensitivity of local dynamic stability measure in load carrying situation. It was concluded that load carrying tasks were associated with declined local dynamic stability, which may result in increased risk of fall accident. This finding has implications in preventing fall accidents associated with occupational load carrying.

  14. Modelling the impact of fungal spore ice nuclei on clouds and precipitation

    International Nuclear Information System (INIS)

    Sesartic, Ana; Lohmann, Ulrike; Storelvmo, Trude

    2013-01-01

    Some fungal spore species have been found in laboratory studies to be very efficient ice nuclei. However, their potential impact on clouds and precipitation is not well known and needs to be investigated. Fungal spores as a new aerosol species were introduced into the global climate model (GCM) ECHAM5-HAM. The inclusion of fungal spores acting as ice nuclei in a GCM leads to only minor changes in cloud formation and precipitation on a global level; however, changes in the liquid water path and ice water path as well as stratiform precipitation can be observed in the boreal regions where tundra and forests act as sources of fungal spores. Although fungal spores contribute to heterogeneous freezing, their impact is reduced by their low numbers as compared to other heterogeneous ice nuclei. (letter)

  15. Recent progress in Bacillus subtilis spore-surface display: concept, progress, and future.

    Science.gov (United States)

    Wang, He; Wang, Yunxiang; Yang, Ruijin

    2017-02-01

    With the increased knowledge on spore structure and advances in biotechnology engineering, the newly developed spore-surface display system confers several inherent advantages over other microbial cell-surface display systems including enhanced stability and high safety. Bacillus subtilis is the most commonly used Bacillus species for spore-surface display. The expression of heterologous antigen or protein on the surface of B. subtilis spores has now been practiced for over a decade with noteworthy success. As an update and supplement to other previous reviews, we comprehensively summarize recent studies in the B. subtilis spore-surface display technique. We focus on its benefits as well as the critical factors affecting its display efficiency and offer suggestions for the future success of this field.

  16. Esterase activity as a novel parameter of spore germination in Bacillus anthracis

    International Nuclear Information System (INIS)

    Ferencko, Linda; Cote, Mindy A.; Rotman, Boris

    2004-01-01

    Spores of Bacillus anthracis were shown to produce esterase activity about 4 min after exposure to conventional germinants such as combinations of amino acids and purine ribosides. Neither amino acids nor ribosides alone induce germination and esterase activity. Expression of esterase activity was chloramphenicol resistant, and correlated with loss of spore refractivity, a traditional parameter of early germination. Based on these observations, we hypothesized that esterase activity could be used as a novel parameter for quantifying early events during spore germination. To test this hypothesis, we measured expression of esterase activity under a variety of germinating conditions. Using diacetyl fluorescein as fluorogenic substrate of esterases, we demonstrated that esterase activity was invariably induced whenever spores were triggered by known germinants. Moreover, D-alanine, an inhibitor of L-alanine-mediated germination, was found to significantly inhibit expression of esterase activity. In terms of molecular mechanisms, esterase expression could represent activation of proteases at the onset of spore germination

  17. The distribution of Paenibacillus larvae spores in adult bees and honey and larval mortality, following the addition of American foulbrood diseased brood or spore-contaminated honey in honey bee (Apis mellifera) colonies.

    Science.gov (United States)

    Lindström, Anders; Korpela, Seppo; Fries, Ingemar

    2008-09-01

    Within colony transmission of Paenibacillus larvae spores was studied by giving spore-contaminated honey comb or comb containing 100 larvae killed by American foulbrood to five experimental colonies respectively. We registered the impact of the two treatments on P. larvae spore loads in adult bees and honey and on larval mortality by culturing for spores in samples of adult bees and honey, respectively, and by measuring larval survival. The results demonstrate a direct effect of treatment on spore levels in adult bees and honey as well as on larval mortality. Colonies treated with dead larvae showed immediate high spore levels in adult bee samples, while the colonies treated with contaminated honey showed a comparable spore load but the effect was delayed until the bees started to utilize the honey at the end of the flight season. During the winter there was a build up of spores in the adult bees, which may increase the risk for infection in spring. The results confirm that contaminated honey can act as an environmental reservoir of P. larvae spores and suggest that less spores may be needed in honey, compared to in diseased brood, to produce clinically diseased colonies. The spore load in adult bee samples was significantly related to larval mortality but the spore load of honey samples was not.

  18. Workshop on the Destruction of Bacterial Spores Held in Brussels, Belgium on May 1-3, 1985.

    Science.gov (United States)

    1985-05-03

    corrmunication. 0 We propose to evaluate the relevance to food processing of recent research ,. on resistance of bacterial spores to heat, and to reappraise the...spores from thermophiles is important in food spoilage . It also is an attribute useful in biological indicator systems • used to evaluate thermal... Bacterial spore injury - an update. 4 Food Prot. 44:776-786. Lewis, J.C., N.S. Snell, and G. Halderton. 1964. Dormancy and activation of :acterial spores, in

  19. Analysis of the Effects of a gerP Mutation on the Germination of Spores of Bacillus subtilis

    Science.gov (United States)

    2012-11-01

    Spores of Bacillus species are metabolically dormant and ex-tremely resistant to a wide variety of agents (38). As a conse- quence, these spores can...permeability barrier in dormant spores, the coat is a permeability barrier to large mole- cules (18, 20). Thus, it is possible that there are special...type and gerP spore germina- tion. Almost all bacteria have an alanine racemase activity essen- tial for the generation of the D-alanine needed for

  20. Germination of Spores of Astrobiologically Relevant Bacillus Species in High-Salinity Environments

    Science.gov (United States)

    Nagler, Katja; Julius, Christina; Moeller, Ralf

    2016-07-01

    In times of increasing space exploration and search for extraterrestrial life, new questions and challenges for planetary protection, aiming to avoid forward contamination of different planets or moons with terrestrial life, are emerging. Spore-forming bacteria such as Bacillus species have a high contamination potential due to their spores' extreme resistance, enabling them to withstand space conditions. Spores require liquid water for their conversion into a growing cell (i.e., spore germination and subsequent growth). If present, water on extraterrestrial planets or moons is likely to be closely associated with salts (e.g., in salty oceans or brines), thus constituting high-salinity environments. Spores of Bacillus subtilis can germinate despite very high salt concentrations, although salt stress does exert negative effects on this process. In this study, germination and metabolic reactivation ("outgrowth") of spores of five astrobiologically relevant Bacillus species (B. megaterium, B. pumilus SAFR-032, B. nealsonii, B. mojavensis, and B. vallismortis) in high salinity (≤3.6 M NaCl) were investigated. Spores of different species exhibited different germination and outgrowth capabilities in high salinity, which strongly depended on germination conditions, especially the exact composition of the medium. In this context, a new "universal" germination trigger for Bacillus spores, named KAGE (KCl, L-alanine, D-glucose, ectoine), was identified, which will be very useful for future comparative germination and outgrowth studies on different Bacillus species. Overall, this study yielded interesting new insights on salt stress effects on spore germination and points out the difficulty of predicting the potential of spores to contaminate salty environments on extraterrestrial celestial bodies.

  1. Artificial neural network models of relationships between Alternaria spores and meteorological factors in Szczecin (Poland)

    Science.gov (United States)

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2008-11-01

    Alternaria is an airborne fungal spore type known to trigger respiratory allergy symptoms in sensitive patients. Aiming to reduce the risk for allergic individuals, we constructed predictive models for the fungal spore circulation in Szczecin, Poland. Monthly forecasting models were developed for the airborne spore concentrations of Alternaria, which is one of the most abundant fungal taxa in the area. Aerobiological sampling was conducted over 2004-2007, using a Lanzoni trap. Simultaneously, the following meteorological parameters were recorded: daily level of precipitation; maximum and average wind speed; relative humidity; and maximum, minimum, average, and dew point temperature. The original factors as well as with lags (up to 3 days) were used as the explaining variables. Due to non-linearity and non-normality of the data set, the modelling technique applied was the artificial neural network (ANN) method. The final model was a split model with classification (spore presence or absence) followed by regression for spore seasons and log(x+1) transformed Alternaria spore concentration. All variables except maximum wind speed and precipitation were important factors in the overall classification model. In the regression model for spore seasons, close relationships were noted between Alternaria spore concentration and average and maximum temperature (on the same day and 3 days previously), humidity (with lag 1) and maximum wind speed 2 days previously. The most important variable was humidity recorded on the same day. Our study illustrates a novel approach to modelling of time series with short spore seasons, and indicates that the ANN method provides the possibility of forecasting Alternaria spore concentration with high accuracy.

  2. Fungal Spore Concentrations and Ergosterol Content in Aerosol Samples in the Caribbean During African Dust Events

    Science.gov (United States)

    Santos-Figueroa, G.; Bolaños-Rosero, B.; Mayol-Bracero, O. L.

    2015-12-01

    Fungal spores are a major component of primary biogenic aerosol particles that are emitted to the atmosphere, are ubiquitous, and play an important role in the chemistry and physics of the atmosphere, climate, and public health. Every year, during summer months, African dust (AD) particles are transported to the Caribbean region causing an increase in the concentrations of particulate matter in the atmosphere. AD is one of the most important natural sources of mineral particulate matter at the global scale, and many investigations suggest that it has the ability to transport dust-associated biological particles through long distances. The relationship between AD incursions and the concentration of fungal spores in the Caribbean region is poorly understood. In order to investigate the effects of AD incursions on fungal spore's emissions, fungal spore concentrations were monitored using a Burkard spore trap at the tropical montane cloud forest of Pico del Este at El Yunque National Forest, Puerto Rico. The presence of AD was supported with satellite images of aerosol optical thickness, and with the results from the air masses backward trajectories calculated with the NOAA HYSPLIT model. Basidiospores and Ascospores comprised the major components of the total spore's concentrations, up to a maximum of 98%, during both AD incursions and background days. A considerably decrease in the concentration of fungal spores during AD events was observed. Ergosterol, biomarker for measuring fungal biomass, concentrations were determined in aerosols that were sampled at a marine site, Cabezas de San Juan Nature Reserve, in Fajardo Puerto Rico, and at an urban site, Facundo Bueso building at the University of Puerto Rico. Additional efforts to understand the relationship between the arrival of AD to the Caribbean and a decrease in spore's concentrations are needed in order to investigate changes in local spore's vs the contribution of long-range spores transported within the AD.

  3. Mass production of spores of lactic acid-producing Rhizopus oryzae NBRC 5384 on agar plate.

    Science.gov (United States)

    Yamane, Tsuneo; Tanaka, Ryosuke

    2013-01-01

    Mass production of sporangiospores (spores) of Rhizopus oryzae NBRC 5384 (identical to NRRL 395 and ATCC 9363) on potato-dextrose-agar medium was studied aiming at starting its L(+)-lactic acid fermentation directly from spore inoculation. Various parameters including harvest time, sowed spore density, size of agar plate, height of air space, and incubation mode of plate (agar-on-bottom or agar-on-top) were studied. Ordinarily used shallow Petri dishes were found out to be unsuitable for the full growth of R. oryzae sporangiophores. In a very wide range of the sowed spore density, the smaller it was, the greater the number of the harvested spores was. It was also interesting to find out that R. oryzae grown downward vertically with a deep air space in an agar-on-top mode gave larger amount of spores than in an agar-on-bottom mode at 30°C for 7-day cultivation. Scale-up of the agar plate culture from 26.4 to 292 cm(2) was studied, resulting in the proportional relationship between the number of the harvested spores/plate and the plate area in the deep Petri dishes. The number of plates of 50 cm in diameter needed for 100 m(3) industrial submerged fermentation started directly from 2 × 10(5) spores/mL inoculum size was estimated as about 6, from which it was inferred that such a fermentation would be feasible. Designing a 50 cm plate and a method of spreading and collecting the spores were suggested. Bioprocess technological significance of the "full-scale industrial submerged fermentation started directly from spore inoculation omitting pre-culture" has been discussed. © 2013 American Institute of Chemical Engineers.

  4. A Gompertz regression model for fern spores germination

    Directory of Open Access Journals (Sweden)

    Gabriel y Galán, Jose María

    2015-06-01

    Full Text Available Germination is one of the most important biological processes for both seed and spore plants, also for fungi. At present, mathematical models of germination have been developed in fungi, bryophytes and several plant species. However, ferns are the only group whose germination has never been modelled. In this work we develop a regression model of the germination of fern spores. We have found that for Blechnum serrulatum, Blechnum yungense, Cheilanthes pilosa, Niphidium macbridei and Polypodium feuillei species the Gompertz growth model describe satisfactorily cumulative germination. An important result is that regression parameters are independent of fern species and the model is not affected by intraspecific variation. Our results show that the Gompertz curve represents a general germination model for all the non-green spore leptosporangiate ferns, including in the paper a discussion about the physiological and ecological meaning of the model.La germinación es uno de los procesos biológicos más relevantes tanto para las plantas con esporas, como para las plantas con semillas y los hongos. Hasta el momento, se han desarrollado modelos de germinación para hongos, briofitos y diversas especies de espermatófitos. Los helechos son el único grupo de plantas cuya germinación nunca ha sido modelizada. En este trabajo se desarrolla un modelo de regresión para explicar la germinación de las esporas de helechos. Observamos que para las especies Blechnum serrulatum, Blechnum yungense, Cheilanthes pilosa, Niphidium macbridei y Polypodium feuillei el modelo de crecimiento de Gompertz describe satisfactoriamente la germinación acumulativa. Un importante resultado es que los parámetros de la regresión son independientes de la especie y que el modelo no está afectado por variación intraespecífica. Por lo tanto, los resultados del trabajo muestran que la curva de Gompertz puede representar un modelo general para todos los helechos leptosporangiados

  5. Microbial modeling of thermal resistance of Alicyclobacillus acidoterrestris CRA7152 spores in concentrated orange juice with nisin addition

    Science.gov (United States)

    Peña, Wilmer Edgard Luera; de Massaguer, Pilar Rodriguez; Teixeira, Luciano Quintão

    2009-01-01

    The nisin effect on thermal death of Alicyclobacillus acidoterrestris CRA 7152 spores in concentrated orange juice (64°Brix) was studied. Concentrations of 0, 50, 75 and 100 IU of nisin/ml juice, at temperatures of 92, 95, 98 and 102°C were evaluated. The quadratic polynomial model was used to analyze the effects of the factors and their interaction. Verification of surviving spores was carried out through plating in K medium (pH 3.7). The results showed that the D values without nisin addition were 25.5, 12.9, 6.1 and 2.3 min for 92, 95, 98 and 102°C respectively. With addition of nisin into the juice there was a drop of heat resistance as the concentration was increased at a same temperature. With 30, 50, 75, 100 and 150 IU/ml at 95°C, the D values were 12.34, 11.38, 10.49, 9.49 and 9.42 min respectively, showing that a decrease in the D value up to 27% can be obtained. The second order polynomial model established with r2 = 0.995 showed that the microorganism resistance was affected by the action of temperature followed by the nisin concentration. Nisin therefore is an alternative for reducing the rigor of the A. acidoterrestris CRA 7152 thermal treatment. PMID:24031405

  6. Variation of desiccation tolerance and longevity in fern spores.

    Science.gov (United States)

    Ballesteros, Daniel; Hill, Lisa M; Walters, Christina

    2017-04-01

    This work contributes to the understanding of plant cell responses to extreme water stress when it is applied at different intensity and duration. Fern spores are used to explore survival at relative humidity (RH)moisture level. A RH of 10-25% corresponds well to sorption behavior parameters and is below the glass transition, measured using differential scanning calorimetry. Though response to RH was similar among species, the kinetics of deterioration varied considerably among species and this implies differences in the structure or mobility of molecules within the solidified cytoplasm. Our work suggests that desiccation damage occurs in desiccation tolerant cells, and that it is expressed as a time-dependent response, otherwise known as aging. Copyright © 2017 Elsevier GmbH. All rights reserved.

  7. Evaluating Composite Sampling Methods of Bacillus spores at Low Concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Hess, Becky M.; Amidan, Brett G.; Anderson, Kevin K.; Hutchison, Janine R.

    2016-10-13

    Restoring facility operations after the 2001 Amerithrax attacks took over three months to complete, highlighting the need to reduce remediation time. The most time intensive tasks were environmental sampling and sample analyses. Composite sampling allows disparate samples to be combined, with only a single analysis needed, making it a promising method to reduce response times. We developed a statistical experimental design to test three different composite sampling methods: 1) single medium single pass composite: a single cellulose sponge samples multiple coupons; 2) single medium multi-pass composite: a single cellulose sponge is used to sample multiple coupons; and 3) multi-medium post-sample composite: a single cellulose sponge samples a single surface, and then multiple sponges are combined during sample extraction. Five spore concentrations of Bacillus atrophaeus Nakamura spores were tested; concentrations ranged from 5 to 100 CFU/coupon (0.00775 to 0.155CFU/cm2, respectively). Study variables included four clean surface materials (stainless steel, vinyl tile, ceramic tile, and painted wallboard) and three grime coated/dirty materials (stainless steel, vinyl tile, and ceramic tile). Analysis of variance for the clean study showed two significant factors: composite method (p-value < 0.0001) and coupon material (p-value = 0.0008). Recovery efficiency (RE) was higher overall using the post-sample composite (PSC) method compared to single medium composite from both clean and grime coated materials. RE with the PSC method for concentrations tested (10 to 100 CFU/coupon) was similar for ceramic tile, painted wall board, and stainless steel for clean materials. RE was lowest for vinyl tile with both composite methods. Statistical tests for the dirty study showed RE was significantly higher for vinyl and stainless steel materials, but significantly lower for ceramic tile. These results suggest post-sample compositing can be used to reduce sample analysis time when

  8. Measuring Social carrying Capacity: An Exploratory Study

    OpenAIRE

    López-Bonilla, Jesús Manuel; López-Bonilla, Luis Miguel

    2007-01-01

    The tourist carrying capacity commands a growing interest given that it is closely linked with sustainable tourist development. The justification of the utility of this concept is given by means of a simple and efficient methodological proposal, by analysing the social carrying capacity. To this end, an empirical application is carried out in the Western Andalusia. In some of the cases analysed, the satisfaction of the tourist is found to decline when the levels of the tourist use are higher ...

  9. Temperature-sensitive heparin-modified poloxamer hydrogel with affinity to KGF facilitate the morphologic and functional recovery of the injured rat uterus.

    Science.gov (United States)

    Xu, He-Lin; Xu, Jie; Zhang, Si-Si; Zhu, Qun-Yan; Jin, Bing-Hui; ZhuGe, De-Li; Shen, Bi-Xin; Wu, Xue-Qing; Xiao, Jian; Zhao, Ying-Zheng

    2017-11-01

    Endometrial injury usually results in intrauterine adhesion (IUA), which is an important cause of infertility and recurrent miscarriage in reproductive women. There is still lack of an effective therapeutic strategy to prevent occurrence of IUA. Keratinocyte growth factor (KGF) is a potent repair factor for epithelial tissues. Here, a temperature-sensitive heparin-modified poloxamer (HP) hydrogel with affinity to KGF (KGF-HP) was used as a support matrix to prevent IUA and deliver KGF. The rheology of KGF-HP hydrogel was carefully characterized. The cold KGF-HP solution was rapidly transited to hydrogel with suitable storage modulus (G') and loss modulus (G″) for the applications of uterus cavity at temperature of 33 °C. In vitro release demonstrated that KGF was released from HP hydrogels in sustained release manner for a long time. In vivo bioluminescence imaging showed that KGF-HP hydrogel was able to prolong the retention of the encapsulated KGF in injured uterus of rat model. Moreover, the morphology and function of the injured uterus were significantly recovered after administration of KGF-HP hydrogel, which were evaluated by two-dimensional ultrasound imaging and receptive fertility. Not only proliferation of endometrial glandular epithelial cells and luminal epithelial cells but also angiogenesis of injured uterus were observed by Ki67 and CD31 staining after 7 d of treatment with KGF-HP hydrogel. Finally, a close relatively relationship between autophagy and proliferation of endometrial epithelial cells (EEC) and angiogenesis was firstly confirmed by detecting expression of LC3-II and P62 after KGF treatment. Overall, KGF-HP may be used as a promising candidate for IUA treatment.

  10. An analysis of the influence of logistics activities on the export cold chain of temperature sensitive fruit through the Port of Cape Town

    Directory of Open Access Journals (Sweden)

    Leila L. Goedhals-Gerber

    2015-09-01

    Full Text Available Background: South Africa exports a large variety of different fruit types and cultivars worldwide. Yet, there is concern in the South African fruit industry that too much fruit and money is lost each year due to breaks along the fresh fruit export cold chain. Objective: The objective of this article was to identify the influence of logistics activities on breaks along the South African fruit export cold chain. The focus is specifically on temperature sensitive fruit, exported in refrigerated containers to Europe and the United Kingdom through the Port of Cape Town. This supply chain was selected as this was the most accessible supply chain in terms of retrieving the necessary temperature data. Method: The cold chain was investigated from the cold store, through all segments, until the Port of Cape Town. Temperature data collected with temperature monitoring devices from different fruit export supply chains of grapes, plums and pome fruit (apples and pears were analysed to identify the percentage of temperature breaks and the length of temperature breaks that occur at each segment of the cold chain. Results: The results show that a large number of breaks are experienced along South Africa’s fruit export cold chain, specifically at the interface between the cold store and the truck. In addition, the findings also show that there has been an improvement in the number of breaks experienced in the Port of Cape Town following the implementation of the NAVIS and Refcon systems. Conclusion: This article concludes by providing the fruit industry with areas that require addressing to improve operational procedures along the fruit export cold chain to help ensure that the fruit arrives at its final destination at optimal quality.

  11. An analysis of the influence of logistics activities on the export cold chain of temperature sensitive fruit through the Port of Cape Town

    Directory of Open Access Journals (Sweden)

    Leila L. Goedhals-Gerber

    2015-02-01

    Full Text Available Background: South Africa exports a large variety of different fruit types and cultivars worldwide. Yet, there is concern in the South African fruit industry that too much fruit and money is lost each year due to breaks along the fresh fruit export cold chain.Objective: The objective of this article was to identify the influence of logistics activities on breaks along the South African fruit export cold chain. The focus is specifically on temperature sensitive fruit, exported in refrigerated containers to Europe and the United Kingdom through the Port of Cape Town. This supply chain was selected as this was the most accessible supply chain in terms of retrieving the necessary temperature data.Method: The cold chain was investigated from the cold store, through all segments, until the Port of Cape Town. Temperature data collected with temperature monitoring devices from different fruit export supply chains of grapes, plums and pome fruit (apples and pears were analysed to identify the percentage of temperature breaks and the length of temperature breaks that occur at each segment of the cold chain.Results: The results show that a large number of breaks are experienced along South Africa’s fruit export cold chain, specifically at the interface between the cold store and the truck. In addition, the findings also show that there has been an improvement in the number of breaks experienced in the Port of Cape Town following the implementation of the NAVIS and Refcon systems.Conclusion: This article concludes by providing the fruit industry with areas that require addressing to improve operational procedures along the fruit export cold chain to help ensure that the fruit arrives at its final destination at optimal quality.

  12. [Effect of traditional Chinese medicines with different properties on thermoregulation and temperature-sensitive transient receptor potentialion channel protein of rats with yeast-induced fever].

    Science.gov (United States)

    Wan, Hong-Ye; Kong, Xiang-Ying; Li, Xiao-Min; Zhu, Hong-Wei; Su, Xiao-Hui; Lin, Na

    2014-10-01

    To compare the intervention effects of four traditional Chinese medicines (TCMs) with typical cold or hot property on body temperature and temperature-sensitive transient receptor potential ion channel proteins (TRPs) of rats with yeast-induced fever. The pyrexia model was induced by injecting yeast suspension subcutaneously. Totally 108 male SD rats were randomly divided into the normal group, the model group, the Rhei Radix et Rhizoma treated group, the Coptidis Rhizoma treated group, the Euodiae Fructus treated group, and the Alpiniae Officinarum Rhizoma treated group, with 18 rats in each group. At the 4 h, 8 h and 12 h after injection of yeast, the rats were sacrificed to collect their hypothalamus and dorsal root ganglion. The expressions of TRPV1 and TRPM8 were detected by immunohistochemistry and Western blot method. Compared with the normal group, after injection of yeast, the temperature of rats in the model group notably increased, and reached the peak at 8 h (P < 0.01). The TRPV1 level in hypothalamus and dorsal root ganglia (DRG) of the model group significantly increased, whereas the TRPM8 level significantly reduced. Compared with the model group, the Rhei Radix et Rhizoma group and the Coptidis Rhizoma group showed significant decrease in the high body temperature of rats caused by yeast, down-regulation in the expression of TRPV1, and up-regulation in the expression of TRPM8 (P < 0.05 or P < 0.01). Euodiae Fructus and Alpiniae Officinarum Rhizoma had no significant effect on either temperature or TRPs of fever rats. Rhei Radix et Rhizoma and Coptidis Rhizoma, both are TCMs with cold property, can reduce the temperature of fever rats induced by yeast, which may be related to their effective regulation of TRPV1 and TRPM8 in hypothalamus and DRG, while Euodiae Fructus and Alpiniae Officinarum Rhizoma had no relevant effect.

  13. Effect of Temperature-Sensitive Poloxamer Solution/Gel Material on Pericardial Adhesion Prevention: Supine Rabbit Model Study Mimicking Cardiac Surgery.

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    Hyun Kang

    Full Text Available We investigated the mobility of a temperature-sensitive poloxamer/Alginate/CaCl2 mixture (PACM in relation to gravity and cardiac motion and the efficacy of PACM on the prevention of pericardial adhesion in a supine rabbit model.A total of 50 rabbits were randomly divided into two groups according to materials applied after epicardial abrasion: PACM and dye mixture (group PD; n = 25 and saline as the control group (group CO; n = 25. In group PD, rabbits were maintained in a supine position with appropriate sedation, and location of mixture of PACM and dye was assessed by CT scan at the immediate postoperative period and 12 hours after surgery. The grade of adhesions was evaluated macroscopically and microscopically two weeks after surgery.In group PD, enhancement was localized in the anterior pericardial space, where PACM and dye mixture was applied, on immediate post-surgical CT scans. However, the volume of the enhancement was significantly decreased at the anterior pericardial space 12 hours later (P < .001. Two weeks after surgery, group PD had significantly lower macroscopic adhesion score (P = .002 and fibrosis score (P = .018 than did group CO. Inflammation score and expression of anti-macrophage antibody in group PD were lower than those in group CO, although the differences were not significant.In a supine rabbit model study, the anti-adhesion effect was maintained at the area of PACM application, although PACM shifted with gravity and heart motion. For more potent pericardial adhesion prevention, further research and development on the maintenance of anti-adhesion material position are required.

  14. Diminished soil functions occur under simulated climate change in a sup-alpine pasture, but heterotrophic temperature sensitivity indicates microbial resilience.

    Science.gov (United States)

    Mills, Robert T E; Gavazov, Konstantin S; Spiegelberger, Thomas; Johnson, David; Buttler, Alexandre

    2014-03-01

    The pressure of climate change is disproportionately high in mountainous regions, and small changes may push ecosystem processes beyond sensitivity thresholds, creating new dynamics of carbon and nutrient cycling. Given that the rate of organic matter decomposition is strongly dependent upon temperature and soil moisture, the sensitivity of soil respiration to both metrics is highly relevant when considering soil-atmosphere feedbacks under a changing climate. To assess the effects of changing climate in a mountain pasture system, we transplanted turfs along an elevation gradient, monitored in situ soil respiration, incubated collected top-soils to determine legacy effects on temperature sensitivity, and analysed soil organic matter (SOM) to detect changes in quality and quantity of SOM fractions. In situ transplantation down-slope reduced soil moisture and increased soil temperature, with concurrent reductions in soil respiration. Soil moisture acted as an overriding constraint to soil respiration, and significantly reduced the sensitivity to temperature. Under controlled laboratory conditions, removal of the moisture constraint to heterotrophic respiration led to a significant respiration-temperature response. However, despite lower respiration rates down-slope, the response function was comparable among sites, and therefore unaffected by antecedent conditions. We found shifts in the SOM quality, especially of the light fraction, indicating changes to the dynamics of decomposition of recently deposited material. Our findings highlighted the resilience of the microbial community to severe climatic perturbations, but also that soil moisture stress during the growing season can significantly reduce soil function in addition to direct effects on plant productivity. This demonstrated the sensitivity of subalpine pastures under climate change, and possible implications for sustainable use given reductions in organic matter turnover and consequent feedbacks to nutrient

  15. Cryogenic Irradiation of Bacillus Atrophaeus spores to understand microbial survival on Icy Bodies

    Science.gov (United States)

    Yerby, C. J.; Noell, A. C.; Hodyss, R. P.; Johnson, P. V.; Ponce, A.

    2017-12-01

    Bacterial Spores are useful indicator organisms for studying the survival of microbes and degradation of biomolecules on the surface of planetary icy bodies. To predict the limits of life's proliferation in space, specifically on icy bodies, it is essential to understand the ability of microbes to withstand photon and particle irradiation at cryogenic temperatures. Bacillus Atrophaeus spores were transferred onto stainless steel coupons by varied processes and subsequently frozen at Europan temperatures (16oK—273oK) in a vacuum at 8.7x10-8 Torr. An argon lamp bombarded the spore-containing coupons with a solar-like radiation spectra for a variety of times, and spores were removed from the coupons and enumerated in culture. To date, (n=43) coupons have been analyzed for spore kill-rates with regards to ice temperature and radiation exposure time. Results will be presented on the effect of cryogenic temperatures in improving radiation resistance of bacterial spores. This works also details methodology improvements by comparing different spore deposition and recovery methods before and after cryogenic irradiation.

  16. Sporangium Exposure and Spore Release in the Peruvian Maidenhair Fern (Adiantum peruvianum, Pteridaceae.

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    Simon Poppinga

    Full Text Available We investigated the different processes involved in spore liberation in the polypod fern Adiantum peruvianum (Pteridaceae. Sporangia are being produced on the undersides of so-called false indusia, which are situated at the abaxial surface of the pinnule margins, and become exposed by a desiccation-induced movement of these pinnule flaps. The complex folding kinematics and functional morphology of false indusia are being described, and we discuss scenarios of movement initiation and passive hydraulic actuation of these structures. High-speed cinematography allowed for analyses of fast sporangium motion and for tracking ejected spores. Separation and liberation of spores from the sporangia are induced by relaxation of the annulus (the 'throwing arm' of the sporangium catapult and conservation of momentum generated during this process, which leads to sporangium bouncing. The ultra-lightweight spores travel through air with a maximum velocity of ~5 m s(-1, and a launch acceleration of ~6300 g is measured. In some cases, the whole sporangium, or parts of it, together with contained spores break away from the false indusium and are shed as a whole. Also, spores can stick together and form spore clumps. Both findings are discussed in the context of wind dispersal.

  17. Mushroom's spore size and time of fruiting are strongly related: is moisture important?

    Science.gov (United States)

    Kauserud, Håvard; Heegaard, Einar; Halvorsen, Rune; Boddy, Lynne; Høiland, Klaus; Stenseth, Nils Chr

    2011-04-23

    Most basidiomycete fungi produce annual short-lived sexual fruit bodies from which billions of microscopic spores are spread into the air during a short time period. However, little is known about the selective forces that have resulted in some species fruiting early and others later in the fruiting season. This study of relationships between morphological and ecological characteristics, climate factors and time of fruiting are based upon thorough statistical analyses of 66 520 mapped records from Norway, representing 271 species of autumnal fruiting mushroom species. We found a strong relationship between spore size and time of fruiting; on average, a doubling of spore size (volume) corresponded to 3 days earlier fruiting. Small-spored species dominate in the oceanic parts of Norway, whereas large-spored species are typical of more continental parts. In separate analyses, significant relationships were observed between spore size and climate factors. We hypothesize that these relationships are owing to water balance optimization, driven by water storage in spores as a critical factor for successful germination of primary mycelia in the drier micro-environments found earlier in the fruiting season and/or in continental climates.

  18. Effect of Coat Layers in Bacillus Subtilis Spores Resistance to Photo-Catalytic Inactivation

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    Luz del Carmen Huesca-Espitia

    2017-10-01

    Full Text Available Different water treatment processes (physical and chemical exist to obtain safe water for human or food industry supply. The advanced oxidation technologies are rising as a new alternative to eliminate undesirable chemicals and waterborne diseases. In this work, we analyze the power of the photo-assisted Fenton process using Fe(II/H2O2 and UV radiation (365 nm to inactivate Bacillus subtilis spores, considered among the most resistant biological structures known. Different concentrations of Fe(II, H2O2 and UV radiation (365 nm were used to inactivate wt and some coat spore mutants of B. subtilis. Wt spores of B. subtilis were inactivated after 60 min using this process. In general, all defective coat mutants were more sensitive than the wt spores and, particularly, the double mutant was 10 folds more sensitive than others being inactivated during the first 10 minutes using soft reaction conditions. Presence of Fe(II ions was found essential for spore inactivating process and, for those spores inactivated using the Fe(II/H2O2 under UV radiation process, it is suggested that coat structures are important to their resistance to the treatment process. The photo-assisted Fenton process using Fe(II, H2O2 and UV radiation (365 nm can be used to inactivate any water microorganisms with the same or less resistance that B. subtilis spores to produce safe drinking water in relatively short treatment time.

  19. Induction of Rhizopus oryzae germination under starvation using host metabolites increases spore susceptibility to heat stress.

    Science.gov (United States)

    Turgeman, Tidhar; Kakongi, Nathan; Schneider, Avishai; Vinokur, Yakov; Teper-Bamnolker, Paula; Carmeli, Shmuel; Levy, Maggie; Skory, Christopher D; Lichter, Amnon; Eshel, Dani

    2014-03-01

    Sweetpotato is a nutritional source worldwide. Soft rot caused by Rhizopus spp. is a major limiting factor in the storage of produce, rendering it potentially unsafe for human consumption. In this study, Rhizopus oryzae was used to develop a concept of postharvest disease control by weakening the pathogen through induction of spore germination under starvation conditions. We isolated the sweetpotato active fractions (SPAFs) that induce spore germination and used them at a low dose to enhance spore weakening caused by starvation. Germination in SPAF at 1 mg/ml weakened the pathogen spores by delaying their ability to form colonies on rich media and by increasing their sensitivity to heat stress. The weakening effect was also supported by reduced metabolic activity, as detected by Alarmar Blue fluorescent dye assays. Spores incubated with SPAF at 1 mg/ml showed DNA fragmentation in some of their nuclei, as observed by TUNEL assay. In addition, these spores exhibited changes in ultrastructural morphology (i.e., shrinkage of germ tubes, nucleus deformation, and vacuole formation) which are hallmarks of programmed cell death. We suggest that induction of spore germination under starvation conditions increases their susceptibility to stress and, therefore, might be considered a new strategy for pathogen control.

  20. Small, acid-soluble proteins bound to DNA protect Bacillus subtilis spores from killing by dry heat.

    OpenAIRE

    Setlow, B; Setlow, P

    1995-01-01

    Dry Bacillus subtilis spores lacking their two major DNA-binding proteins (small, acid-soluble proteins [SASP] alpha and beta) were much more sensitive to dry heat than were wild-type spores. Survivors of dry heat treatment of both wild-type and mutant spores exhibited a high frequency of mutations, and the DNA from the heated spores had increased numbers of single-strand breaks. These data indicate that SASP alpha and beta provide significant protection to spore DNA against the damaging effe...

  1. Effect of plasterboard composition on Stachybotrys chartarum growth and biological activity of spores.

    Science.gov (United States)

    Murtoniemi, Timo; Nevalainen, Aino; Hirvonen, Maija-Riitta

    2003-07-01

    The effects of plasterboard composition on the growth and sporulation of Stachybotrys chartarum as well as on the inflammatory potential of the spores were studied. S. chartarum was grown on 13 modified plasterboards under saturated humidity conditions. The biomass was estimated by measuring the ergosterol content of the S. chartarum culture while the spore-induced cytotoxicity and production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), and interleukin-6 in mouse macrophages was used to illustrate the bioactivity of spores. The ergosterol content of S. chartarum correlated with the number of spores collected from plasterboards. The growth and sporulation decreased compared to that of the reference board in those cases where (i) the liner was treated with biocide, (ii) starch was removed from the plasterboard, or (iii) desulfurization gypsum was used in the core. Spores collected from all the plasterboards were toxic to the macrophages. The biocide added to the core did not reduce the growth; in fact, the spores collected from that board evoked the highest cytotoxicity. The conventional additives used in the core had inhibitory effects on growth. Recycled plasterboards used in the core and the board lacking the starch triggered spore-induced TNF-alpha production in macrophages. In summary, this study shows that the growth of a strain of S. chartarum on plasterboard and the subsequent bioactivity of spores were affected by minor changes to the composition of the core or liners, but it could not be totally prevented without resorting to the use of biocides. However, incomplete prevention of microbial growth by biocides even increased the cytotoxic potential of the spores.

  2. A Clostridium difficile-Specific, Gel-Forming Protein Required for Optimal Spore Germination

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    M. Lauren Donnelly

    2017-01-01

    Full Text Available Clostridium difficile is a Gram-positive spore-forming obligate anaerobe that is a leading cause of antibiotic-associated diarrhea worldwide. In order for C. difficile to initiate infection, its aerotolerant spore form must germinate in the gut of mammalian hosts. While almost all spore-forming organisms use transmembrane germinant receptors to trigger germination, C. difficile uses the pseudoprotease CspC to sense bile salt germinants. CspC activates the related subtilisin-like protease CspB, which then proteolytically activates the cortex hydrolase SleC. Activated SleC degrades the protective spore cortex layer, a step that is essential for germination to proceed. Since CspC incorporation into spores also depends on CspA, a related pseudoprotease domain, Csp family proteins play a critical role in germination. However, how Csps are incorporated into spores remains unknown. In this study, we demonstrate that incorporation of the CspC, CspB, and CspA germination regulators into spores depends on CD0311 (renamed GerG, a previously uncharacterized hypothetical protein. The reduced levels of Csps in gerG spores correlate with reduced responsiveness to bile salt germinants and increased germination heterogeneity in single-spore germination assays. Interestingly, asparagine-rich repeat sequences in GerG’s central region facilitate spontaneous gel formation in vitro even though they are dispensable for GerG-mediated control of germination. Since GerG is found exclusively in C. difficile, our results suggest that exploiting GerG function could represent a promising avenue for developing C. difficile-specific anti-infective therapies.

  3. Laboratory Investigations on the Survival of Bacillus subtilis Spores in Deliquescent Salt Mars Analog Environments

    Science.gov (United States)

    Nuding, Danielle L.; Gough, Raina V.; Venkateswaran, Kasthuri J.; Spry, James A.; Tolbert, Margaret A.

    2017-10-01

    Observed features such as recurring slope lineae suggest that liquid water may exist on the surface and near-subsurface of Mars today. The presence of this liquid water, likely in the form of a brine, has important implications for the present-day water cycle, habitability, and planetary protection policies. It is possible that this water is formed, at least partially, by deliquescence of salts, a process during which hygroscopic salts absorb water vapor from the atmosphere and form a saturated liquid brine. We performed laboratory experiments to examine the ability of Bacillus subtilis (B-168) spores, alone or mixed with calcium perchlorate salt (Ca(ClO4)2), to form liquid water via deliquescence under Mars-relevant conditions. Spore survival after exposure to these conditions was examined. An environmental chamber was used to expose the samples to temperature and relative humidity (RH) values similar to those found on Mars, and Raman microscopy was used to identify the phases of water and salt that were present and to confirm the presence of spores. We found that B-168 spores did not condense any detectable water vapor on their own during the diurnal cycle, even at 100% RH. However, when spores were mixed with perchlorate salt, the entire sample deliquesced at low RH values, immersing the spores in a brine solution during the majority of the simulated martian temperature and humidity cycle. After exposure to the simulated diurnal cycles and, in some cases, perchlorate brine, the impact of each environmental scenario on spore survival was estimated by standard plate assay. We found that, if there are deliquescent salts in contact with spores, there is a mechanism for the spores to acquire liquid water starting with only atmospheric water vapor as the H2O source. Also, neither crystalline nor liquid Ca(ClO4)2 is sporicidal despite the low water activity.

  4. Evaluation of the effects of fragmented steam exposure cycles on the survival of bacterial spores.

    Science.gov (United States)

    Shirtz, J T; Soli, T C; Allen, W E; Stellwag, E J; McConnell, T J

    1999-01-01

    The purpose of this study was to examine the population and resistance characteristics of bacterial spores which have been exposed to an abbreviated steam sterilization cycle. The philosophy of many pharmaceutical manufacturers is to require a second complete terminal sterilization cycle in the event of an unplanned interruption during the terminal sterilization of a production batch. The impact of abbreviated steam sterilization cycles was examined for their effect on the survivability and resistance of bacterial spores following an inadequate sterilization cycle. Steam sterilization cycles of two minutes and four minutes were performed on separate groups of Biological Indicator spore strips. These groups were then held at room temperature and re-exposed to a range of sterilization conditions after 24, 48, and 72 hours, i.e., start cycle, abort, hold, start cycle, abort. Spore survivor curves were calculated and resistance estimations were determined. The results of the study indicated that the log level of the surviving spores remained fairly constant, but variability within groups increased as sterilization time increased. The resistance of these surviving spores, as measured by D value, also remained relatively constant throughout the holding period. Abbreviated cycles were similarly conducted on ampules containing a spore suspension, and the spore populations and moist heat resistances were determined over time. Contrary to the spore strip, the population of the subject ampules was less stable showing a gradual decline over the same observation period. The study also included a comparison of the surviving population of short and long fragmented cycles. The results of this study demonstrate that a second complete sterilization cycle is unnecessary to assure the absence of living matter in the sterilized units.

  5. Intestinal calcium and bile salts facilitate germination of Clostridium difficile spores.

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    Travis J Kochan

    2017-07-01

    Full Text Available Clostridium difficile (C. difficile is an anaerobic gram-positive pathogen that is the leading cause of nosocomial bacterial infection globally. C. difficile infection (CDI typically occurs after ingestion of infectious spores by a patient that has been treated with broad-spectrum antibiotics. While CDI is a toxin-mediated disease, transmission and pathogenesis are dependent on the ability to produce viable spores. These spores must become metabolically active (germinate in order to cause disease. C. difficile spore germination occurs when spores encounter bile salts and other co-germinants within the small intestine, however, the germination signaling cascade is unclear. Here we describe a signaling role for Ca2+ during C. difficile spore germination and provide direct evidence that intestinal Ca2+ coordinates with bile salts to stimulate germination. Endogenous Ca2+ (released from within the spore and a putative AAA+ ATPase, encoded by Cd630_32980, are both essential for taurocholate-glycine induced germination in the absence of exogenous Ca2+. However, environmental Ca2+ replaces glycine as a co-germinant and circumvents the need for endogenous Ca2+ fluxes. Cd630_32980 is dispensable for colonization in a murine model of C. difficile infection and ex vivo germination in mouse ileal contents. Calcium-depletion of the ileal contents prevented mutant spore germination and reduced WT spore germination by 90%, indicating that Ca2+ present within the gastrointestinal tract plays a critical role in C. difficile germination, colonization, and pathogenesis. These data provide a biological mechanism that may explain why individuals with inefficient intestinal calcium absorption (e.g., vitamin D deficiency, proton pump inhibitor use are more prone to CDI and suggest that modulating free intestinal calcium is a potential strategy to curb the incidence of CDI.

  6. The use of germinants to potentiate the sensitivity of Bacillus anthracis spores to peracetic acid

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    Ozgur eCelebi

    2016-01-01

    Full Text Available Elimination of Bacillus anthracis spores from the environment is a difficult and costly process due in part to the toxicity of current sporicidal agents. For this reason we investigated the ability of the spore germinants L-alanine (100 mM and inosine (5 mM to reduce the concentration of peracetic acid (PAA required to inactivate B.anthracis spores. While L-alanine significantly enhanced (p=0.0085 the bactericidal activity of 500 ppm PAA the same was not true for inosine suggesting some form of negative interaction. In contrast the germinant combination proved most effective at 100 ppm PAA (p=0.0009. To determine if we could achieve similar results in soil we treated soil collected from the burial site of an anthrax infected animal which had been supplemented with spores of the Sterne strain of B.anthracis to increase the level of contamination to 104 spores/g. Treatment with germinants followed one hour later by 5000 ppm PAA eliminated all of the spores. In contrast direct treatment of the animal burial site using this approach delivered using a back pack sprayer had no detectable effect on the level of B.anthracis contamination or on total culturable bacterial numbers over the course of the experiment. It did trigger a significant, but temporary, reduction (p<0.0001 in the total spore count suggesting that germination had been triggered under real world conditions. In conclusion, we have shown that the application of germinants increase the sensitivity of bacterial spores to PAA. While the results of the single field trial were inconclusive, the study highlighted the potential of this approach and the challenges faced when attempting to perform real world studies on B.anthracis spores contaminated sites.

  7. Decolorization of indigo carmine by laccase displayed on Bacillus subtilis spores.

    Science.gov (United States)

    Cho, Eun-Ah; Seo, Jiyoung; Lee, Dong-Woo; Pan, Jae-Gu

    2011-06-10

    Blue multicopper oxidases, laccases displayed on the surface of Bacillus spores were used to decolorize a widely used textile dyestuff, indigo carmine. The laccase-encoding gene of Bacillus subtilis, cotA, was cloned and expressed in B. subtilis DB104, and the expressed enzyme was spontaneously localized on Bacillus spores. B. subtilis spores expressing laccase exhibited maximal activity for the oxidation of 2,2'-azino-bis (3-ethylthiazoline-6-sulfonate) (ABTS) at pH 4.0 and 80°C, and for the decolorization of indigo carmine at pH 8.0 and 60°C. The displayed enzyme retained 80% of its original activity after pre-treatment with organic solvents such as 50% acetonitrile and n-hexane for 2h at 37°C. The apparent K(m) of the enzyme displayed on spores was 443±124 μM for ABTS with a V(max) of 150 ± 16 U/mg spores. Notably, 1mg of spores displaying B. subtilis laccase (3.4 × 10(2)U for ABTS as a substrate) decolorized 44.6 μg indigo carmine in 2h. The spore reactor (0.5 g of spores corresponding to 1.7×10(5)U in 50 mL) in a consecutive batch recycling mode decolorized 223 mg indigo carmine/L to completion within 42 h at pH 8.0 and 60°C. These results suggest that laccase displayed on B. subtilis spores can serve as a powerful environmental tool for the treatment of textile dye effluent. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. The fastest flights in nature: high-speed spore discharge mechanisms among fungi.

    Directory of Open Access Journals (Sweden)

    Levi Yafetto

    Full Text Available BACKGROUND: A variety of spore discharge processes have evolved among the fungi. Those with the longest ranges are powered by hydrostatic pressure and include "squirt guns" that are most common in the Ascomycota and Zygomycota. In these fungi, fluid-filled stalks that support single spores or spore-filled sporangia, or cells called asci that contain multiple spores, are pressurized by osmosis. Because spores are discharged at such high speeds, most of the information on launch processes from previous studies has been inferred from mathematical models and is subject to a number of errors. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we have used ultra-high-speed video cameras running at maximum frame rates of 250,000 fps to analyze the entire launch process in four species of fungi that grow on the dung of herbivores. For the first time we have direct measurements of launch speeds and empirical estimates of acceleration in these fungi. Launch speeds ranged from 2 to 25 m s(-1 and corresponding accelerations of 20,000 to 180,000 g propelled spores over distances of up to 2.5 meters. In addition, quantitative spectroscopic methods were used to identify the organic and inorganic osmolytes responsible for generating the turgor pressures that drive spore discharge. CONCLUSIONS/SIGNIFICANCE: The new video data allowed us to test different models for the effect of viscous drag and identify errors in the previous approaches to modeling spore motion. The spectroscopic data show that high speed spore discharge mechanisms in fungi are powered by the same levels of turgor pressure that are characteristic of fungal hyphae and do not require any special mechanisms of osmolyte accumulation.

  9. Detection of Bacillus anthracis spores and a model protein using PEMC sensors in a flow cell at 1 mL/min.

    Science.gov (United States)

    Campbell, Gossett A; Mutharasan, Raj

    2006-07-15

    Piezoelectric-excited millimeter-sized cantilever (PEMC) sensors of 4mm(2) sensing area were immobilized with antibody specific to Bacillus anthracis (anti-BA) spores or bovine serum albumin (anti-BSA). Detection of pathogen (Bacillus anthracis (BA) at 300 spores/mL) and BSA (1 mg/mL) were investigated under both stagnant and flow conditions. Two flow cell designs were evaluated by characterizing flow-induced resonant frequency shifts. One of the flow cells labeled SFC-2 (hold-up volume of 0.3 mL), showed small fluctuations (+/-20 Hz) around a common resonant frequency response of 217 Hz in the flow rate range of 1-17 mL/min. The total resonant frequency change obtained for the binding of 300 spores/mL in 1h was 90+/-5 Hz (n=2), and 162+/-10 Hz (n=2) under stagnant and flow conditions, respectively. Binding of antibodies, anti-BA and anti-BSA, were more rapid under flow than under stagnant conditions. The sensor was repeatedly exposed to BSA with an intermediate release step. The first and second responses to BSA were nearly identical. The total resonant frequency response to BSA was 388+/-10 (n=2) Hz under flow conditions. Kinetic analysis is carried out to quantify the effect of flow rate on antibody immobilization and the two types of detection experiments.

  10. Production of flavour ketones in aqueous-organic two-phase systems by using free and microencapsulated fungal spores as biocatalysts.

    Science.gov (United States)

    Park; Holland; Khan; Vulfson

    2000-02-01

    The formation of 2-alkanones by free and microencapsulated P. roquefortii spores in an aqueous-organic two-phase system was investigated by using substrates supplied as a solution in decane. It was shown that the spores remained catalytically active after entrapment within permeable polyamide microcapsules and readily catalyzed the formation of 2-pentanone, 2-heptanone, and 2-undecanone from short-chain alkyl esters of hexanoic, octanoic, and lauric acid, respectively, with the rate of reaction being markedly dependent on the type and concentration of the ester substrate used. In general, the optimal concentration of the esters in decane was found to be much higher than that of the respective fatty acid substrates and, in the case of alkyl dodecanoates, the biotransformation could be carried out efficiently even in the absence of added solvent. Further analysis revealed a significant difference in the reaction rates observed with free and microencapsulated spores at 0.5 but not at 3.0 M methyl dodecanoate, suggesting that at high substrate concentrations the biotransformation was no longer limited by mass transfer.

  11. Bivalve carrying capacity in coastal ecosystems

    NARCIS (Netherlands)

    Dame, R.F.; Prins, T.C.

    1998-01-01

    carrying capacity of suspension feeding bivalves in 11 coastal and estuarine ecosystems is examined. Bivalve carrying capacity is defined in terms of water mass residence time, primary production time and bivalve clearance time. Turnover times for the 11 ecosystems are compared both two and three

  12. The Concept of Carrying Capacity in Tourism

    Directory of Open Access Journals (Sweden)

    Josef Zelenka

    2014-05-01

    Full Text Available Carrying capacity is often pragmatically, theoretically as well as purely intuitively considered as a concept in the context of tourism sustainability. The carrying capacity application has the greatest potential in protected areas, in frequently visited cultural and natural attractions, and in relation to sustaining of the lifestyle of the local community and tourism destination potential in general. Despite its importance, partial applications, determination of basic theoretical principles, and specifying connection to the other theoretical concepts in tourism (particularly destination life cycle, LAC concept, visitors management, there still is a rightful opinion of some authors suggesting that there is no consistent theory of tourism carrying capacity. This theory would be the base for sophisticated practical carrying capacity applications. This paper is therefore focused on introduction of the theoretical concept of carrying capacity, which can be discussed and possibly further elaborated.

  13. Effect of relative humidity on the aerodynamic diameter and respiratory deposition of fungal spores

    Science.gov (United States)

    Reponen, Tiina; Willeke, Klaus; Ulevicius, Vidmantas; Reponen, Auvo; Grinshpun, Sergey A.

    Exposure to airborne fungal spores may cause respiratory symptoms. The hygroscopicity of airborne spores may significantly affect their aerodynamic diameter, and thus change their deposition pattern in the human respiratory tract. We have investigated the change in aerodynamic diameter of five different fungal species as a function of relative humidity. Liquid and dry dispersion methods were explored for the aerosolization of the fungal spores. A new system that produces non-aggregated spore aerosol directly from a moldy surface was designed and found suitable for this study. The spores were aerosolized from a mold growth on agar by ducting dry air over the surface, and spore chains in the flow were broken up by passing the entire flow through a critical orifice. Size-spectrometric measurements with an Aerodynamic Particle Sizer showed that the aerodynamic diameter of the tested fungal spores does not change significantly when the relative humidity increases from 30% to 90%. A more distinct spore size increase was found at a relative humidity of ˜ 100%. The highest change of the aerodynamic diameter was found with Cladosporium cladosporioides: it increased from 1.8 μm to 2.3 μm when the relative humidity increased from 30% to ˜ 100%. The size increase corresponds to an approximate doubling of the particle volume. In order to estimate the effect of hygroscopic growth on the respiratory deposition of spores, the mean depositions in the human respiratory tract were calculated for fungal spores with various size changes due to hygroscopic growth. A recently developed model of the International Commission of Radiological Protection was used for the respiratory deposition calculations. We found that the 27% increase in Cladosporium size results in a 20-30% increase in the respiratory deposition of these spores. We conclude that most fungal spores are only slightly hygroscopic and the hygroscopic increase does not significantly affect their respiratory deposition. Our

  14. Deposition of Bacteria and Bacterial Spores by Bathroom Hot Air Hand Dryers.

    Science.gov (United States)

    Del Carmen Huesca-Espitia, Luz; Aslanzadeh, Jaber; Feinn, Richard; Joseph, Gabrielle; Murray, Thomas S; Setlow, Peter

    2018-02-09

    Hot air hand dryers in multiple men's and women's bathrooms in 3 basic science research areas in an academic health center were screened for their deposition on plates of: i) total bacteria, some of which were identified; and ii) a kanamycin resistant Bacillus subtilis strain, PS533, spores of which are produced in large amounts in one basic science research laboratory. Plates exposed to hand dryer air for 30 seconds averaged 18-60 colonies/plate but interior hand dryer nozzle surfaces had minimal bacterial levels, plates exposed to bathroom air for 2 minutes with hand dryers off averaged ≤1 colony, and plates exposed to bathroom air moved by a small fan for 20 minutes had averages of 15 and 12 colonies/plate in two buildings tested. Retrofitting hand dryers with HEPA filters reduced bacterial deposition by hand dryers ∼4-fold, and potential human pathogens were recovered from plates exposed to hand dryer air whether or not a HEPA filter was present, and from bathroom air moved by a small fan. Spore-forming colonies, identified as B. subtilis PS533 averaged ∼2.5-5% of bacteria deposited by hand dryers throughout basic research areas examined regardless of distance from the spore forming laboratory, and these were almost certainly deposited as spores. Comparable results were obtained when bathroom air was sampled for spores. These results indicate that many kinds of bacteria, including potential pathogens and spores, can be deposited on hands exposed to bathroom hand dryers, and that spores could be dispersed throughout buildings and deposited on hands by hand dryers. Importance While there is evidence that bathroom hand dryers can disperse bacteria from hands or deposit bacteria on surfaces, including recently washed hands, there is less information on: i) the organisms dispersed by hand dryers; ii) if hand dryers provide a reservoir of bacteria or simply blow large amounts of bacterially contaminated air; and iii) if bacterial spores are deposited on

  15. The immunological characteristics and probiotic function of recombinant Bacillus subtilis spore expressing Clonorchis sinensis cysteine protease.

    Science.gov (United States)

    Tang, Zeli; Shang, Mei; Chen, Tingjin; Ren, Pengli; Sun, Hengchang; Qu, Hongling; Lin, Zhipeng; Zhou, Lina; Yu, Jinyun; Jiang, Hongye; Zhou, Xinyi; Li, Xuerong; Huang, Yan; Xu, Jin; Yu, Xinbing

    2016-12-19

    Clonorchiasis, a food-borne zoonosis, is caused by Clonorchis sinensis. The intestinal tract and bile ducts are crucial places for C. sinensis metacercariae to develop into adult worms. The endospore of Bacillus subtilis is an ideal oral immunization vehicle for delivery of heterologous antigens to intestine. Cysteine protease of C. sinensis (CsCP) is an endogenous key component in the excystment of metacercariae and other physiological or pathological processes. We constructed a fusion gene of CotC (a coat protein)-CsCP and obtained B. subtilis spores with recombinant plasmid of pEB03-CotC-CsCP (B.s-CotC-CsCP). CotC-CsCP expressed on spores' surface was detected by Western blotting and immunofluorescence. Immunological characteristics of recombinant spore coat protein were evaluated in a mouse model. The levels of CsCP-specific antibodies were detected by ELISA. Effects of recombinant spores on mouse intestine were evaluated by histological staining. The activities of biochemical enzymes in serum were assayed by microplate. Liver sections of infected mice were evaluated by Ishak score after Masson's trichrome. The B.s-CotC-CsCP spores displayed CsCP on their coat. Specific IgG and isotypes were significantly induced by coat proteins of B.s-CotC-CsCP spores after subcutaneous immunization. IgA levels in intestinal mucus and bile of B.s-CotC-CsCP orally treated mice significantly increased. Additionally, more IgA-secreting cells were observed in enteraden and lamina propria regions of the mouse jejunum, and an increased amount of acidic mucins in intestines were also observed. There were no significant differences in enzyme levels of serum among groups. No inflammatory injury was observed in the intestinal tissues of each group. The degree of liver fibrosis was significantly reduced after oral immunization with B.s-CotC-CsCP spores. Bacillus subtilis spores maintained the original excellent immunogenicity of CsCP expressed on their surface. Both local and systemic

  16. Development and fine structure of sclerotia and spores of the actinomycete Chainia olivacea.

    Science.gov (United States)

    Sharples, G P; Williams, S T

    1976-01-01

    Sclerotia and spores of Chainia olivacea were studied by transmission and scanning electron microscopy. Sclerotia formed by repeated branching of several hyphea. Branch tips were delimited by septa and increased in size, becoming filled with lipid-like inclusions. In mautre sclerotia, empty cells and intra-hyphal growth were observed. An electron-dense fibrillar material was deposited between hyphae and on the sclerotium surface. The similarities between these and the sclerotia of certain fungi are discussed. Spores were formed in a manner similar to that in Streptomyces species. Large inter-sporal pads were formed during ingrowth of the septa delimiting the spores.

  17. Single Spore Isolation as a Simple and Efficient Technique to obtain fungal pure culture

    Science.gov (United States)

    Noman, E.; Al-Gheethi, AA; Rahman, N. K.; Talip, B.; Mohamed, R.; H, N.; Kadir, O. A.

    2018-04-01

    The successful identification of fungi by phenotypic methods or molecular technique depends mainly on the using an advanced technique for purifying the isolates. The most efficient is the single spore technique due to the simple requirements and the efficiency in preventing the contamination by yeast, mites or bacteria. The method described in the present work is depends on the using of a light microscope to transfer one spore into a new culture medium. The present work describes a simple and efficient procedure for single spore isolation to purify of fungi recovered from the clinical wastes.

  18. Photoinduction of Spore Germination in Marchantia polylmorpha L.is Mediated by Photosynthesis

    OpenAIRE

    Tadashi, Nakazato; Akeo, Kadota; Masamitsu, Wada; Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University; Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University; Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University

    1999-01-01

    The effects of light on spore germination (protrusion of protonemata) in the liverwort Marchantia polymorpha L.were examined. Spore germination was found to be light dependent and light irradiation for 10h or longer was necessary. Test using specific wavelengths showed that the entire spectrum from near UV to red light was effective, red light being the most effective. Spore germination could be induced by intermittent irradiation with 15-min red light pulses given every 1 or 2 h for 24 h. Th...

  19. Feasibility of flotation concentration of fungal spores as a method to identify toxigenic mushrooms

    Directory of Open Access Journals (Sweden)

    Bazzle LJ

    2014-12-01

    Full Text Available Lisa J Bazzle,1 Marc A Cubeta,2 Steven L Marks,1 David C Dorman3 1Department of Clinical Sciences, College of Veterinary Medicine, 2Department of Plant Pathology, College of Agriculture and Life Sciences, Center for Integrated Fungal Research, 3Department of Molecular and Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA Purpose: Mushroom poisoning is a recurring and challenging problem in veterinary medicine. Diagnosis of mushroom exposure in animals is hampered by the lack of rapid diagnostic tests. Our study evaluated the feasibility of using flotation concentration and microscopic evaluation of spores for mushroom identification. Evaluation of this method in living animals exposed to toxigenic mushrooms is limited by ethical constraints; therefore, we relied upon the use of an in vitro model that mimics the oral and gastric phases of digestion. Methods: In our study, mycologist-identified toxigenic (poisonous and nontoxigenic fresh mushrooms were collected in North Carolina, USA. In phase 1, quantitative spore recovery rates were determined following magnesium sulfate, modified Sheather's sugar solution, and zinc sulfate flotation (n=16 fungal species. In phase 2, mushrooms (n=40 fungal species were macerated and digested for up to 2 hours in a salivary and gastric juice simulant. The partially digested material was acid neutralized, filtered, and spores concentrated using zinc sulfate flotation followed by microscopic evaluation of spore morphology. Results: Mean spore recovery rates for the three flotation fluids ranged from 32.5% to 41.0% (P=0.82. Mean (± standard error of the mean Amanita spp. spore recovery rates were 38.1%±3.4%, 36.9%±8.6%, and 74.5%±1.6% (P=0.0012 for the magnesium sulfate, Sheather's sugar, and zinc sulfate solutions, respectively. Zinc sulfate flotation following in vitro acid digestion (phase 2 yielded spore numbers adequate for microscopic visualization in

  20. The effects of meteorological factors on airborne fungal spore concentration in two areas differing in urbanisation level

    Science.gov (United States)

    Oliveira, M.; Ribeiro, H.; Delgado, J. L.; Abreu, I.

    2009-01-01

    Although fungal spores are an ever-present component of the atmosphere throughout the year, their concentration oscillates widely. This work aims to establish correlations between fungal spore concentrations in Porto and Amares and meteorological data. The seasonal distribution of fungal spores was studied continuously (2005-2007) using volumetric spore traps. To determine the effect of meteorological factors (temperature, relative humidity and rainfall) on spore concentration, the Spearman rank correlation test was used. In both locations, the most abundant fungal spores were Cladosporium, Agaricus, Agrocybe, Alternaria and Aspergillus/Penicillium, the highest concentrations being found during summer and autumn. In the present study, with the exception of Coprinus and Pleospora, spore concentrations were higher in the rural area than in the urban location. Among the selected spore types, spring-autumn spores ( Coprinus, Didymella, Leptosphaeria and Pleospora) exhibited negative correlations with temperature and positive correlations both with relative humidity and rainfall level. On the contrary, late spring-early summer (Smuts) and summer spores ( Alternaria, Cladosporium, Epicoccum, Ganoderma, Stemphylium and Ustilago) exhibited positive correlations with temperature and negative correlations both with relative humidity and rainfall level. Rust, a frequent spore type during summer, had a positive correlation with temperature. Aspergillus/Penicillium, showed no correlation with the meteorological factors analysed. This knowledge can be useful for agriculture, allowing more efficient and reliable application of pesticides, and for human health, by improving the diagnosis and treatment of respiratory allergic disease.

  1. Effects of meteorological factors on airborne bracken ( Pteridium aquilinum (L.) Kuhn.) spores in Salamanca (middle-west Spain)

    Science.gov (United States)

    Rodríguez de La Cruz, David; Sánchez Reyes, Estefanía; Sánchez Sánchez, José

    2009-05-01

    Temporal variation of airborne bracken ( Pteridium aquilinum) spores concentration in Salamanca during 10 years from January 1998 to December 2007 were studied by using a Burkard spore trap, and correlations with some meteorological parameters were analyzed. The number of spores that were counted was very low, due probably to the distance between the spore trap and the main bracken populations which were located 70 km away from the city. Long-range transport caused by winds coming from the Second Quadrant (IIQ) is supposed to be responsible for the appearance of bracken spores in Salamanca. The season period from August to late October shows the most intense spore dispersal process, with an early morning distribution along the day. Years 2002 and 2007 with a low quantity of airborne spores were also characterized by low mean temperatures, always under 18°C from May to June. Daily spore concentration shows positive correlation with temperature and sun hours but negative with IVQ winds and with relative humidity. No correlation between daily spore concentration and rainfall was found. Also, a positive correlation between number of spores and IIQ winds was observed during the main spore season (MSS) and prepeak period (PRE).

  2. Optical and structural properties of plasma-treated Cordyceps bassiana spores as studied by circular dichroism, absorption, and fluorescence spectroscopy

    Science.gov (United States)

    Lee, Geon Joon; Sim, Geon Bo; Choi, Eun Ha; Kwon, Young-Wan; Kim, Jun Young; Jang, Siun; Kim, Seong Hwan

    2015-01-01

    To understand the killing mechanism of fungal spores by plasma treatment, the optical, structural, and biological properties of the insect pathogenic fungus Cordyceps bassiana spores were studied. A nonthermal atmospheric-pressure plasma jet (APPJ) was used to treat the spores in aqueous solution. Optical emission spectra of the APPJ acquired in air indicated emission peaks corresponding to hydroxyl radicals and atomic oxygen. When the APPJ entered the aqueous solution, additional reactive species were derived from the interaction of plasma radicals with the aqueous solution. Fluorescence and absorption spectroscopy confirmed the generation of hydroxyl radicals and hydrogen peroxide in the plasma-activated water (PAW). Spore counting showed that plasma treatment significantly reduced spore viability. Absorption spectroscopy, circular dichroism (CD) spectroscopy, and agarose gel electrophoresis of the DNA extracted from plasma-treated spores showed a reduction in spore DNA content. The magnitude of the dip in the CD spectrum was lower in the plasma-treated spores than in the control, indicating that plasma treatment causes structural modifications and/or damage to cellular components. Tryptophan fluorescence intensity was lower in the plasma-treated spores than in the control, suggesting that plasma treatment modified cell wall proteins. Changes in spore viability and DNA content were attributed to structural modification of the cell wall by reactive species coming from the APPJ and the PAW. Our results provided evidence that the plasma radicals and the derived reactive species play critical roles in fungal spore inactivation.

  3. Optical and structural properties of plasma-treated Cordyceps bassiana spores as studied by circular dichroism, absorption, and fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Geon Joon, E-mail: gjlee@kw.ac.kr; Sim, Geon Bo; Choi, Eun Ha [Plasma Bioscience Research Center/Department of Electrical and Biological Physics, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Kwon, Young-Wan [KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-701 (Korea, Republic of); Kim, Jun Young; Jang, Siun; Kim, Seong Hwan, E-mail: piceae@naver.com [Department of Microbiology and Institute of Basic Sciences, Dankook University, Cheonan 330-714 (Korea, Republic of)

    2015-01-14

    To understand the killing mechanism of fungal spores by plasma treatment, the optical, structural, and biological properties of the insect pathogenic fungus Cordyceps bassiana spores were studied. A nonthermal atmospheric-pressure plasma jet (APPJ) was used to treat the spores in aqueous solution. Optical emission spectra of the APPJ acquired in air indicated emission peaks corresponding to hydroxyl radicals and atomic oxygen. When the APPJ entered the aqueous solution, additional reactive species were derived from the interaction of plasma radicals with the aqueous solution. Fluorescence and absorption spectroscopy confirmed the generation of hydroxyl radicals and hydrogen peroxide in the plasma-activated water (PAW). Spore counting showed that plasma treatment significantly reduced spore viability. Absorption spectroscopy, circular dichroism (CD) spectroscopy, and agarose gel electrophoresis of the DNA extracted from plasma-treated spores showed a reduction in spore DNA content. The magnitude of the dip in the CD spectrum was lower in the plasma-treated spores than in the control, indicating that plasma treatment causes structural modifications and/or damage to cellular components. Tryptophan fluorescence intensity was lower in the plasma-treated spores than in the control, suggesting that plasma treatment modified cell wall proteins. Changes in spore viability and DNA content were attributed to structural modification of the cell wall by reactive species coming from the APPJ and the PAW. Our results provided evidence that the plasma radicals and the derived reactive species play critical roles in fungal spore inactivation.

  4. Survival of B. Horneckiae Spores Under Ground-simulated Space Conditions

    Science.gov (United States)

    Schanche, Bradley

    2012-01-01

    To prevent forward contamination and maintain the scientific integrity of future life detection missions, it is important to characterize and attempt to eliminate terrestrial microorganisms associated with exploratory spacecraft and landing vehicles. Among the organisms isolated from spacecraft-associated habitats, spore-forming microbes are highly resistant to various physical and chemical conditions, which include ionizing and UV radiation, desiccation and oxidative stress, and the harsh environment of outer space or planetary surfaces. Recently a radiation resistant, spore forming bacterial isolate, Bacillus horneckiae, was isolated from a clean room of the Kennedy Space Center where the Phoenix spacecraft was assembled. The exceptionally high tolerance of extreme conditions demonstrated by sporeforming bacteria highlighted the need to assess the viability of these microbes in situ (in real) space. The proposed BOSS (Biofilm Organisms Surfing Space) project aims to understand the mechanisms by which biofilm forming organisms, such as B. horneckiae, will potentially be able to withstand harsh space conditions. As previously stated, the spore producing ability of these species gives them increased survivability to harsh conditions. Some of the spores will have the protective exosporium layer artificially removed before the test to determine if the existence of this layer significantly changes the survivability during the mission. In preparation for that experiment, we analyzed spores which were exposed during a ground simulation, the EXPOSE R2 Biofilm Organisms Surfing Space (BOSS). Previous to exposure, spores were deposited onto spacecraft grade aluminum coupons in a spore suspension calculated to contain between 10(exp 7) and 10(exp 8) spores. This precursor series will be used to establish a baseline survivability function for comparison with the future flight tests during EXPOSE-R. For each coupon, a 10% polyvinyl alcohol (PVA) film was applied and peeled

  5. Roles of DacB and spm proteins in clostridium perfringens spore resistance to moist heat, chemicals, and UV radiation.

    Science.gov (United States)

    Paredes-Sabja, Daniel; Sarker, Nahid; Setlow, Barbara; Setlow, Peter; Sarker, Mahfuzur R

    2008-06-01

    Clostridium perfringens food poisoning is caused mainly by enterotoxigenic type A isolates that typically possess high spore heat resistance. Previous studies have shown that alpha/beta-type small, acid-soluble proteins (SASP) play a major role in the resistance of Bacillus subtilis and C. perfringens spores to moist heat, UV radiation, and some chemicals. Additional major factors in B. subtilis spore resistance are the spore's core water content and cortex peptidoglycan (PG) structure, with the latter properties modulated by the spm and dacB gene products and the sporulation temperature. In the current work, we have shown that the spm and dacB genes are expressed only during C. perfringens sporulation and have examined the effects of spm and dacB mutations and sporulation temperature on spore core water content and spore resistance to moist heat, UV radiation, and a number of chemicals. The results of these analyses indicate that for C. perfringens SM101 (i) core water content and, probably, cortex PG structure have little if any role in spore resistance to UV and formaldehyde, presumably because these spores' DNA is saturated with alpha/beta-type SASP; (ii) spore resistance to moist heat and nitrous acid is determined to a large extent by core water content and, probably, cortex structure; (iii) core water content and cortex PG cross-linking play little or no role in spore resistance to hydrogen peroxide; (iv) spore core water content decreases with higher sporulation temperatures, resulting in spores that are more resistant to moist heat; and (v) factors in addition to SpmAB, DacB, and sporulation temperature play roles in determining spore core water content and thus, spore resistance to moist heat.

  6. Seasonal and Diurnal Variation of Atmospheric Fungal Spore Concentrations in Hyderabad; Tandojam-Sindh and the Effects of Climatic Conditions

    International Nuclear Information System (INIS)

    Khan, M.; Parveen, A.; Qaisar, M.

    2016-01-01

    Airborne biological particles are present in every type of environment. Different types of geographical localities have different type of airspora, which affect human health. The current study is conducted for the first time to identify the airborne fungal spores from Hyderabad: Tando-Jam, Sindh. For this purpose, Burkard's 7-Days recording volumetric spore trap was used for a period of one year. A total of 68,183 spores/m/sup 3/ were recorded throughout the study period, belonging to 41 fungal spores types. The presented data revealed that Deuteromycetes spore type was predominant. Cladosporium sp. spores were detected in the highest concentration i.e., 50.83 percent, which was followed by Aspergillus sp. (18.63 percent) and Alternaria sp. (11.04 percent). The highest spore count was captured in the month of September-2008 (17,294 spores/m/sup 3/), while lowest spore count was found in the month of June-2009. Diurnal patterns of individual fungal spore types was observed to be mid-day to evening maxima for various species. Spearman rank correlation coefficient r was determined for correlation of fungal spore counts with climatic factors by using IBM software SPSS ver. 20. Results of the current study revealed that fungal spore concentration was increased in high humid weather while low count was found in hot and windy climate that was also confirmed by statistical analysis. The presented work demonstrated that various types of allergenic and phytopathogenic fungal spores were present in the atmosphere of Hyderabad: Tando-Jam. It was also observed that meteorological conditions had a significant impact on dispersal and concentration of fungal spores. (author)

  7. Properties of information carrying waves in cosmology

    International Nuclear Information System (INIS)

    O'Shea, E.M.

    2004-01-01

    Recently we studied the effects of information carrying waves propagating through isotropic cosmologies. By information carrying we mean that the waves have an arbitrary dependence on a function. We found that the waves introduce shear and anisotropic stress into the universe. We then constructed explicit examples of pure gravity wave perturbations for which the presence of this anisotropic stress is essential and the null hypersurfaces playing the role of the histories of the wavefronts in the background space-time are shear free. Motivated by this result we now prove that these two properties are true for all information carrying waves in isotropic cosmologies

  8. Population growth and earth's human carrying capacity.

    Science.gov (United States)

    Cohen, J E

    1995-07-21

    Earth's capacity to support people is determined both by natural constraints and by human choices concerning economics, environment, culture (including values and politics), and demography. Human carrying capacity is therefore dynamic and uncertain. Human choice is not captured by ecological notions of carrying capacity that are appropriate for nonhuman populations. Simple mathematical models of the relation between human population growth and human carrying capacity can account for faster-than-exponential population growth followed by a slowing population growth rate, as observed in recent human history.

  9. Gun Carrying by High School Students in Boston, MA: Does Overestimation of Peer Gun Carrying Matter?

    Science.gov (United States)

    Hemenway, David; Vriniotis, Mary; Johnson, Renee M.; Miller, Matthew; Azrael, Deborah

    2011-01-01

    This paper investigates: (1) whether high school students overestimate gun carrying by their peers, and (2) whether those students who overestimate peer gun carrying are more likely to carry firearms. Data come from a randomly sampled survey conducted in 2008 of over 1700 high school students in Boston, MA. Over 5% of students reported carrying a…

  10. Interplay of PA-X and NS1 Proteins in Replication and Pathogenesis of a Temperature-Sensitive 2009 Pandemic H1N1 Influenza A Virus.

    Science.gov (United States)

    Nogales, Aitor; Rodriguez, Laura; DeDiego, Marta L; Topham, David J; Martínez-Sobrido, Luis

    2017-09-01

    Influenza A viruses (IAVs) cause seasonal epidemics and occasional pandemics, representing a serious public health concern. It has been described that one mechanism used by some IAV strains to escape the host innate immune responses and modulate virus pathogenicity involves the ability of the PA-X and NS1 proteins to inhibit the host protein synthesis in infected cells. It was reported that for the 2009 pandemic H1N1 IAV (pH1N1) only the PA-X protein had this inhibiting capability, while the NS1 protein did not. In this work, we have evaluated, for the first time, the combined effect of PA-X- and NS1-mediated inhibition of general gene expression on virus pathogenesis, using a temperature-sensitive, live-attenuated 2009 pandemic H1N1 IAV (pH1N1 LAIV). We found that viruses containing PA-X and NS1 proteins that simultaneously have (PA WT + /NS1 MUT + ) or do not have (PA MUT - /NS1 WT - ) the ability to block host gene expression showed reduced pathogenicity in vivo However, a virus where the ability to inhibit host protein expression was switched between PA-X and NS1 (PA MUT - /NS1 MUT + ) presented pathogenicity similar to that of a virus containing both wild-type proteins (PA WT + /NS1 WT - ). Our findings suggest that inhibition of host protein expression is subject to a strict balance, which can determine the successful progression of IAV infection. Importantly, knowledge obtained from our studies could be used for the development of new and more effective vaccine approaches against IAV. IMPORTANCE Influenza A viruses (IAVs) are one of the most common causes of respiratory infections in humans, resulting in thousands of deaths annually. Furthermore, IAVs can cause unpredictable pandemics of great consequence when viruses not previously circulating in humans are introduced into humans. The defense machinery provided by the host innate immune system limits IAV replication; however, to counteract host antiviral activities, IAVs have developed different inhibition

  11. Field trials with the use of a live attenuated temperature-sensitive vaccine for the control of Mycoplasma gallisepticum infection in meat-type turkeys

    Directory of Open Access Journals (Sweden)

    Mario Saita

    2010-01-01

    Full Text Available Mycoplasma gallisepticum (MG continues to be an important pathogen of poultry, causing significant production losses in many parts of the world. Eradication is the preferred method of control but it could result impractical after the organism has been introduced in an area with high density of poultry farms. TS-11®, a temperature-sensitive live attenuated MG vaccine, is currently utilized in several countries for the control of MG infections in commercial layers and broiler breeders. In the present field trial, conducted in an industrial meat-turkey farm (belonging to an integrated company, previously affected by severe MG infections, the ability of TS-11® in effectively colonizing the upper respiratory tract in a turkey flock was evaluated (“TS-11®” flock. A second flock grown in an adjacent pen of the same farm was vaccinated with an inactivated MG vaccine (“Inactivated” flock. Polymerase Chain Reaction (PCR and Random Amplified Polymorphic DNA (RAPD analysis were applied for the detection and differentiation of TS-11® from other MG strains possibly present in the same flocks, such as the field strains and the 6/85 live vaccine strain currently utilized in commercial layers in Italy. PCR-RAPD results achieved in the “TS-11®“ flock were compared with those of a flock of turkey grown in the same farm but vaccinated with an inactivated MG vaccine. Encouraging results were achieved by means of PCR-RAPD detection of TS-11® from all of the samples up to eight weeks post vaccination, whereas it was never detected in the “Inactivated” flock. Moreover, the field strain was never detected in the “TS-11®“ flock but in the “Inactivated” one it was detected either 5 and 8 weeks after the vaccination. The aggregate production data of the two flocks resulted significantly improved when compared to the performance of the previous flocks grown in the same farm and similar to the production standard of the integrated company.

  12. Sectoring patterns of spontaneous and radiation-induced somatic pink mutations in the stamen hairs of a temperature-sensitive mutable clone of Tradescantia

    International Nuclear Information System (INIS)

    Ichikawa, Sadao

    1994-01-01

    The sectoring patterns of somatic pink mutations were analyzed in the stamen hairs of Tradescantia clone KU 20, a temperature-sensitive mutable clone. This clone is a blue/pink heterozygote, and its spontaneous pink mutation frequency increases up to about 40-fold at lower temperature. In order to elucidate the mutable nature of this clone, the sectoring patterns were analyzed on 1,123 spontaneous pink mutant events and on 2,725 pink mutant events induced by 0.606 and 1.28 Gy of gamma rays. The average number of pink cells per terminal pink mutant event (a row of pink cells including the terminal cell of a hair) occurred spontaneously was 7.40, whereas the number for the terminal pink mutant event induced by gamma rays varied from 3.33 to 9.88 depending on the post-irradiation days, i.e., increased gradually as the number of days proceeded, then was stabilized at the level of spontaneous mutations after about three weeks. The average number of pink cells per interstitial pink mutant event (a single pink cell or two or more contiguous pink cells between blue cells was 1.97 for spontaneous mutations, while the number for induced mutations varied also depending on the post-irradiation days. The ratio of the number of interstitial pink mutant events against that of terminal pink mutant events was 1.35 for spontaneous mutations, but the ratio for induced mutations varied also with post-irradiation period reaching 2.89 at the peak, indicating that more interstitial pink mutant events are induced by gamma rays than terminal pink mutant events, as compared with spontaneous mutations. The frequency of multiple pink mutant sectors in a hair was more than four times higher than that expected from independent occurrences in case of spontaneous mutations, while the frequency was close to the expectation in induced mutations. suggesting that somatic recombination is involved as one of the major causes of spontaneous mutations in this mutable clone. (author)

  13. Universal nucleic acids sample preparation method for cells, spores and their mixture

    Science.gov (United States)

    Bavykin, Sergei [Darien, IL

    2011-01-18

    The present invention relates to a method for extracting nucleic acids from biological samples. More specifically the invention relates to a universal method for extracting nucleic acids from unidentified biological samples. An advantage of the presently invented method is its ability to effectively and efficiently extract nucleic acids from a variety of different cell types including but not limited to prokaryotic or eukaryotic cells and/or recalcitrant organisms (i.e. spores). Unlike prior art methods which are focused on extracting nucleic acids from vegetative cell or spores, the present invention effectively extracts nucleic acids from spores, multiple cell types or mixtures thereof using a single method. Important that the invented method has demonstrated an ability to extract nucleic acids from spores and vegetative bacterial cells with similar levels effectiveness. The invented method employs a multi-step protocol which erodes the cell structure of the biological sample, isolates, labels, fragments nucleic acids and purifies labeled samples from the excess of dye.

  14. Rupturing of Biological Spores As a Source of Secondary Particles in Amazonia.

    Science.gov (United States)

    China, Swarup; Wang, Bingbing; Weis, Johannes; Rizzo, Luciana; Brito, Joel; Cirino, Glauber G; Kovarik, Libor; Artaxo, Paulo; Gilles, Mary K; Laskin, Alexander

    2016-11-15

    Airborne biological particles, such as fungal spores and pollen, are ubiquitous in the Earth's atmosphere and may influence the atmospheric environment and climate, impacting air quality, cloud formation, and the Earth's radiation budget. The atmospheric transformations of airborne biological spores at elevated relative humidity remain poorly understood and their climatic role is uncertain. Using an environmental scanning electron microscope (ESEM), we observed rupturing of Amazonian fungal spores and subsequent release of submicrometer size fragments after exposure to high humidity. We find that fungal fragments contain elements of inorganic salts (e.g., Na and Cl). They are hygroscopic in nature with a growth factor up to 2.3 at 96% relative humidity, thus they may potentially influence cloud formation. Due to their hygroscopic growth, light scattering cross sections of the fragments are enhanced by up to a factor of 10. Furthermore, rupturing of fungal spores at high humidity may explain the bursting events of new particle formation in Amazonia.

  15. The Ultraviolet Photochemistry and Photobiology of Vegetative Cells and Spores of Bacillus megaterium

    Science.gov (United States)

    Donnellan, J. E.; Stafford, R. S.

    1968-01-01

    The ultraviolet (UV) photochemistry and photobiology of spores and vegetative cells of Bacillus megaterium have been studied. The response of vegetative cells of B. megaterium appears qualitatively similar to those of Escherichia coli, Micrococcus radiodurans, and Bacillus subtilis with respect to photoproduct formation and repair mechanisms. UV irradiation, however, does not produce cyclobutane-type thymine dimers in the DNA of spores, although other thymine photo-products are produced. The photoproducts do not disappear after photoreactivation, but they are eliminated from the DNA by a dark-repair mechanism different from that found for dimers in vegetative cells. Irradiations performed at three wavelengths produce the same amounts of spore photoproduct and give the same survival curves. Variation of the sporulation medium before irradiation results in comparable alterations in the rate of spore photoproduct production and in survival. PMID:4966691

  16. Characterization of the Surface Morphology of Bacillus Spores by Atomic Force Microscopy

    National Research Council Canada - National Science Library

    Zolock, Ruth

    2002-01-01

    .... kurstaki, Bacillus cereus strain 569, and Bacillus globigii var. niger. The spores were separated from a nutrient agar culture by filtering and centrifugation, suspended in deionized water, and immobilized on a graphite substrate by spin-coating...

  17. Lethality of Bacillus Anthracis Spores Due to Short Duration Heating Measured Using Infrared Spectroscopy

    National Research Council Canada - National Science Library

    Goetz, Kristina M

    2005-01-01

    In this research, Bacillus anthracis spores were subjected to bursts of heat lasting on the order of one second in duration using a laser system to simulate the explosive environment from an agent defeat weapon...