WorldWideScience

Sample records for fungal spore germination

  1. Synergistic effects of ajoene and the microwave power density memories of water on germination inhibition of fungal spores.

    Science.gov (United States)

    Rai, S; Singh, U P; Mishra, G D; Singh, S P; Samarketu; Wagner, K G

    1995-05-01

    The synergistic effects of ajoene and the microwave power density memories of water on germination inhibition of some fungal spores are examined. The study reveals power memory varying different synergistic effects of different concentrations of ajoene on the inhibition of spore germination.

  2. Germination inhibitors of fungal spores: identification and mode of action

    NARCIS (Netherlands)

    Chitarra, G.S.

    2003-01-01

    Fungi can be found in a wide variety of environments, such as seeds, plants, soil, water, insects, and food products. Fungi and their toxic metabolites cause losses of food products, and diseases in plants and animals, and may have adverse effects on human health. A crucial step in fungal

  3. Modeling of fungal and bacterial spore germination under static and dynamic conditions.

    Science.gov (United States)

    Peleg, Micha; Normand, Mark D

    2013-11-01

    Isothermal germination curves, sigmoid and nonsigmoid, can be described by a variety of models reminiscent of growth models. Two of these, which are consistent with the percent of germinated spores being initially zero, were selected: one, Weibullian (or "stretched exponential"), for more or less symmetric curves, and the other, introduced by Dantigny's group, for asymmetric curves (P. Dantigny, S. P.-M. Nanguy, D. Judet-Correia, and M. Bensoussan, Int. J. Food Microbiol. 146:176-181, 2011). These static models were converted into differential rate models to simulate dynamic germination patterns, which passed a test for consistency. In principle, these and similar models, if validated experimentally, could be used to predict dynamic germination from isothermal data. The procedures to generate both isothermal and dynamic germination curves have been automated and posted as freeware on the Internet in the form of interactive Wolfram demonstrations. A fully stochastic model of individual and small groups of spores, developed in parallel, shows that when the germination probability is constant from the start, the germination curve is nonsigmoid. It becomes sigmoid if the probability monotonically rises from zero. If the probability rate function rises and then falls, the germination reaches an asymptotic level determined by the peak's location and height. As the number of individual spores rises, the germination curve of their assemblies becomes smoother. It also becomes more deterministic and can be described by the empirical phenomenological models.

  4. Initiation of bacterial spore germination.

    Science.gov (United States)

    Vary, J C; Halvorson, H O

    1968-04-01

    To investigate the problem of initiation in bacterial spore germination, we isolated, from extracts of dormant spores of Bacillus cereus strain T and B. licheniformis, a protein that initiated spore germination when added to a suspension of heat-activated spores. The optimal conditions for initiatory activity of this protein (the initiator) were 30 C in 0.01 to 0.04 m NaCl and 0.01 m tris(hydroxymethyl)aminomethane (pH 8.5). The initiator was inhibited by phosphate but required two co-factors, l-alanine (1/7 of K(m) for l-alanine-inhibited germination) and nicotinamide adenine dinucleotide (1.25 x 10(-4)m). In the crude extract, the initiator activity was increased 3.5-fold by heating the extract at 65 C for 10 min, but the partially purified initiator preparation was completely heat-sensitive (65 C for 5 min). Heat stability could be conferred on the purified initiator by adding 10(-3)m dipicolinic acid. A fractionation of this protein that excluded l-alanine dehydrogenase and adenosine deaminase from the initiator activity was developed. The molecular weight of the initiator was estimated as 7 x 10(4). The kinetics of germination in the presence of initiator were examined at various concentrations of l-alanine and nicotinamide adenine dinucleotide.

  5. Recent advances in germination of Clostridium spores.

    Science.gov (United States)

    Olguín-Araneda, Valeria; Banawas, Saeed; Sarker, Mahfuzur R; Paredes-Sabja, Daniel

    2015-05-01

    Members of Clostridium genus are a diverse group of anaerobic spore-formers that includes several pathogenic species. Their anaerobic requirement enhances the importance of the dormant spore morphotype during infection, persistence and transmission. Bacterial spores are metabolically inactive and may survive for long times in the environment and germinate in presence of nutrients termed germinants. Recent progress with spores of several Clostridium species has identified the germinant receptors (GRs) involved in nutrient germinant recognition and initiation of spore germination. Signal transduction from GRs to the downstream effectors remains poorly understood but involves the release of dipicolinic acid. Two mechanistically different cortex hydrolytic machineries are present in Clostridium spores. Recent studies have also shed light into novel biological events that occur during spore formation (accumulation of transcriptional units) and transcription during early spore outgrowth. In summary, this review will cover all of the recent advances in Clostridium spore germination. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  6. Self-inhibition of spore germination via reactive oxygen in the fungus Cladosporium cucumerinum, causal agent of cucurbit scab

    Science.gov (United States)

    Cladosporium cucumerinum spore germination in vitro depended on spore suspension density. Different fungal isolates displayed maximum germination at different spore concentrations. For one isolate, maximum spore density was observed at both 18 and 25 °C, although germination percentage increased sli...

  7. Measuring Total and Germinable Spore Populations

    Science.gov (United States)

    Noell, A.C.; Yung, P.T.; Yang, W.; Lee, C.; Ponce, A.

    2011-01-01

    It has been shown that bacterial endospores can be enumerated using a microscopy based assay that images the luminescent halos from terbium ions bound to dipicolinic acid, a spore specific chemical marker released upon spore germination. Further development of the instrument has simplified it towards automation while at the same time improving image quality. Enumeration of total spore populations has also been developed allowing measurement of the percentage of viable spores in any population by comparing the germinable/culturable spores to the total. Percentage viability will allow a more quantitative comparison of the ability of spores to survive across a wide range of extreme environments.

  8. Detecting Cortex Fragments During Bacterial Spore Germination.

    Science.gov (United States)

    Francis, Michael B; Sorg, Joseph A

    2016-06-25

    The process of endospore germination in Clostridium difficile, and other Clostridia, increasingly is being found to differ from the model spore-forming bacterium, Bacillus subtilis. Germination is triggered by small molecule germinants and occurs without the need for macromolecular synthesis. Though differences exist between the mechanisms of spore germination in species of Bacillus and Clostridium, a common requirement is the hydrolysis of the peptidoglycan-like cortex which allows the spore core to swell and rehydrate. After rehydration, metabolism can begin and this, eventually, leads to outgrowth of a vegetative cell. The detection of hydrolyzed cortex fragments during spore germination can be difficult and the modifications to the previously described assays can be confusing or difficult to reproduce. Thus, based on our recent report using this assay, we detail a step-by-step protocol for the colorimetric detection of cortex fragments during bacterial spore germination.

  9. Bacterial spore germination and protein mobility.

    Science.gov (United States)

    Moir, Anne

    2003-10-01

    Fluorescence recovery after photobleaching (FRAP) of green fluorescent protein (GFP) has been used to report on protein mobility in single spores. Proteins found in dormant Bacillus spores are not mobile; however, mobility is restored when germination occurs and the core rehydrates. Spores of a cwlD mutant, in which the cortex is resistant to hydrolysis, are able to complete the earliest stages of germination in response to a specific germinant stimulus; in these circumstances, the protein in the spore remains immobile. Therefore, the earliest stages of spore germination, including loss of resistance to extreme heat and the complete release of the spore component dipicolinic acid, are achieved without the restoration of protein mobility.

  10. Phospholipase Cδ regulates germination of Dictyostelium spores

    Directory of Open Access Journals (Sweden)

    Van Haastert Peter JM

    2001-12-01

    Full Text Available Abstract 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 is essential to sense the environment of food-activated spores. Results Plc-null spores germinate at alkaline pH, reduced temperature or increased osmolarity, conditions at which the emerging amoebae can not grow. In contrast, food-activated wild-type spores return to dormancy till conditions in the environment allow growth. The analysis of inositol 1,4,5-trisphosphate (IP3 levels and the effect of added IP3 uncover an unexpected mechanism how PLC regulates spore germination: i deletion of PLC induces the enhanced activity of an IP5 phosphatase leading to high IP3 levels in plc-null cells; ii in wild-type spores unfavourable conditions inhibit PLC leading to a reduction of IP3 levels; addition of exogenous IP3 to wild-type spores induces germination at unfavourable conditions; iii in plc-null spores IP3 levels remain high, also at unfavourable environmental conditions. Conclusions The results imply that environmental conditions regulate PLC activity and that IP3 induces spore germination; the uncontrolled germination of plc-null spores is not due to a lack of PLC activity but to the constitutive activation of an alternative IP3-forming pathway.

  11. 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

  12. Bacillus subtilis Spores Germinate in the Chicken Gastrointestinal Tract▿

    OpenAIRE

    Stephen T Cartman; La Ragione, Roberto M.; Woodward, Martin J.

    2008-01-01

    A number of poultry probiotics contain bacterial spores. In this study, orally administered spores of Bacillus subtilis germinated in the gastrointestinal (GI) tracts of chicks. Furthermore, 20 h after spores were administered, vegetative cells outnumbered spores throughout the GI tract. This demonstrates that spore-based probiotics may function in this host through metabolically active mechanisms.

  13. 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.

  14. Spore Cortex Hydrolysis Precedes Dipicolinic Acid Release during Clostridium difficile Spore Germination

    OpenAIRE

    2015-01-01

    Bacterial spore germination is a process whereby a dormant spore returns to active, vegetative growth, and this process has largely been studied in the model organism Bacillus subtilis. In B. subtilis, the initiation of germinant receptor-mediated spore germination is divided into two genetically separable stages. Stage I is characterized by the release of dipicolinic acid (DPA) from the spore core. Stage II is characterized by cortex degradation, and stage II is activated by the DPA released...

  15. Surface tension propulsion of fungal spores.

    Science.gov (United States)

    Noblin, Xavier; Yang, Sylvia; Dumais, Jacques

    2009-09-01

    Most basidiomycete fungi actively eject their spores. The process begins with the condensation of a water droplet at the base of the spore. The fusion of the droplet onto the spore creates a momentum that propels the spore forward. The use of surface tension for spore ejection offers a new paradigm to perform work at small length scales. However, this mechanism of force generation remains poorly understood. To elucidate how fungal spores make effective use of surface tension, we performed a detailed mechanical analysis of the three stages of spore ejection: the transfer of energy from the drop to the spore, the work of fracture required to release the spore from its supporting structure and the kinetic energy of the spore after ejection. High-speed video imaging of spore ejection in Auricularia auricula and Sporobolomyces yeasts revealed that drop coalescence takes place over a short distance ( approximately 5 microm) and energy transfer is completed in less than 4 mus. Based on these observations, we developed an explicit relation for the conversion of surface energy into kinetic energy during the coalescence process. The relation was validated with a simple artificial system and shown to predict the initial spore velocity accurately (predicted velocity: 1.2 m s(-1); observed velocity: 0.8 m s(-1) for A. auricula). Using calibrated microcantilevers, we also demonstrate that the work required to detach the spore from the supporting sterigma represents only a small fraction of the total energy available for spore ejection. Finally, our observations of this unique discharge mechanism reveal a surprising similarity with the mechanics of jumping in animals.

  16. Anthrax Toxins in Context of Bacillus anthracis Spores and Spore Germination.

    Science.gov (United States)

    Cote, Christopher K; Welkos, Susan L

    2015-08-17

    The interaction of anthrax toxin or toxin components with B. anthracis spores has been demonstrated. Germinating spores can produce significant amounts of toxin components very soon after the initiation of germination. In this review, we will summarize the work performed that has led to our understanding of toxin and spore interactions and discuss the complexities associated with these interactions.

  17. Pulling the trigger: the mechanism of bacterial spore germination.

    Science.gov (United States)

    Foster, S J; Johnstone, K

    1990-01-01

    In spite of displaying the most extreme dormancy and resistance properties known among living systems, bacterial endospores retain an alert environment-sensing mechanism that can respond within seconds to the presence of specific germinants. This germination response is triggered in the absence of both germinant and germinant-stimulated metabolism. Genes coding for components of the sensing mechanism in spores of Bacillus subtilis have been cloned and sequenced. However, the molecular mechanism whereby these receptors interact with germinants to initiate the germination response is unknown. Recent evidence has suggested that in spores of Bacillus megaterium KM, proteolytic activation of an autolytic enzyme constitutes part of the germination trigger reaction.

  18. Workshop report: modeling the molecular mechanism of bacterial spore germination and elucidating reasons for germination heterogeneity.

    Science.gov (United States)

    Indest, Karl J; Buchholz, Wallace G; Faeder, Jim R; Setlow, Peter

    2009-08-01

    Over the course of 2 days, top researchers in the fields of bacterial spore biology and computational biology discussed approaches to determine the cause of spore germination heterogeneity. Biological and mathematical data gaps were identified, and experimental approaches and computational strategies for modeling spore germination were presented and evaluated. As a result of these interactions, future research directions were defined, the outcome of which should result in a robust model to help define the molecular mechanism(s) of spore germination. Mechanistic understanding of germination will be instrumental for developing novel sterilization, treatment, and decontamination strategies to mitigate threats posed by spores.

  19. Mechanisms of Induction of Germination of Bacillus subtilis Spores by High Pressure

    OpenAIRE

    Paidhungat, Madan; Setlow, Barbara; Daniels, William B.; Hoover, Dallas; Papafragkou, Efstathia; Setlow, Peter

    2002-01-01

    Spores of Bacillus subtilis lacking all germinant receptors germinate >500-fold slower than wild-type spores in nutrients and were not induced to germinate by a pressure of 100 MPa. However, a pressure of 550 MPa induced germination of spores lacking all germinant receptors as well as of receptorless spores lacking either of the two lytic enzymes essential for cortex hydrolysis during germination. Complete germination of spores either lacking both cortex-lytic enzymes or with a cortex not att...

  20. Oxidative damage involves in the inhibitory effect of nitric oxide on spore germination of Penicillium expansum.

    Science.gov (United States)

    Lai, Tongfei; Li, Boqiang; Qin, Guozheng; Tian, Shiping

    2011-01-01

    The effects of nitric oxide (NO) on spore germination of Penicillium expansum were investigated and a possible mechanism was evaluated. The results indicated that NO released by sodium nitroprusside (SNP) significantly suppressed fungal growth. With the use of an oxidant sensitive probe and Western blot analysis, an increased level of intracellular reactive oxygen species (ROS) and enhanced carbonylation damage were detected in spores of P. expansum under NO stress. Exogenous superoxide dismutase (SOD) and ascorbic acid (Vc) could increase the resistance of the spore to the inhibitory effect of NO. The activities of SOD and catalase (CAT), as well as ATP content in spores under NO stress were also lower than those in the control. We suggest that NO in high concentration induces the generation of ROS which subsequently causes severe oxidative damage to proteins crucial to the process of spore germination of P. expansum.

  1. Influence of dinitroorthocresol (DNOC on physiology and morphology of soil fungi. III. The effect of various concentrations of DNOC on spore germination activity and morphology of germ tubes

    Directory of Open Access Journals (Sweden)

    Teresa Korniłłowicz

    2014-08-01

    Full Text Available In the present paper low concentrations (l -10 mcg/ml of DNOC, in general, were not found to restrain germination of fungal spores. High concentrations (25-200 mcg/ml were sporostatic and sporocidal Disturbances of fungal spore germination in the presence of DNOC were often accompanied by morphological changes of spores and germ tubes, Mucor mucedo under the influence of DNOC developed budding cels besides hyphae.

  2. In vitro spore germination and gametophytic growth development of ...

    African Journals Online (AJOL)

    SAM

    2014-06-04

    Jun 4, 2014 ... Maximum spore germination rates (84%) were observed in. 70 g/L of sucrose and .... two weeks and gametophyte growth rates (length, width of ..... Smith AR, Pryer KM, Schuettpelz E, Korall P, Schneider H, Wolf PG. (2006).

  3. 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

    SECURITY CLASSIFICATION OF: The germination of multiple individual Bacillus subtilis spores by a high pressure (HP) of 140-150 (unless noted...otherwise) megaPascals (MPa) that activates spore germinant receptors (GRs) was monitored by phase contrast microscopy in a diamond anvil cell. Major...conclusions were that: i) >95% of spores germinated in 40 min; ii) individual spore’s HP germination kinetics were very similar to those for nutrient

  4. 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 elimina

  5. Arbuscular mycorrhizal hyphopodia and germinated spore exudates trigger Ca²⁺ spiking in the legume and nonlegume root epidermis

    National Research Council Canada - National Science Library

    Mireille Chabaud; Andrea Genre; Björn J. Sieberer; Antonella Faccio; Joëlle Fournier; Mara Novero; David G. Barker; Paola Bonfante

    2011-01-01

    ...) fungi in the host root epidermis following pre-infection hyphopodium formation in both legumes and nonlegumes, and to determine to what extent these responses could be mimicked by germinated fungal spore exudate...

  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. 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.

  8. Source strength of fungal spore aerosolization from moldy building material

    Energy Technology Data Exchange (ETDEWEB)

    Gorny, Rafa L.; Reponen, Tiina; Grinshpun, Sergey A.; Willeke, Klaus [Cincinnati Univ., Dept. of Environmental Health, Cincinnati, OH (United States)

    2001-07-01

    The release of Aspergillus versicolor, Cladosporium cladosporioides, and Penicillium melinii spores from agar and ceiling tile surfaces was tested under different controlled environmental conditions using a newly designed and constructed aerosolization chamber. This study revealed that all the investigated parameters, such as fungal species, air velocity above the surface, texture of the surface, and vibration of contaminated material, affected the fungal spore release. It was found that typical indoor air currents can release up to 200 spores cm {sup -2} from surface with fungal spores during 30-min experiments. The release of fungal spores from smooth agar surfaces was found to be inadequate for accurately predicting the emission from rough ceiling tile surfaces because the air turbulence increases the spore release from a rough surface. A vibration of a frequency of 1Hz at a power level of 14W resulted in a significant increase in the spore release rate. The release appears to depend on the morphology of the fungal colonies grown on ceiling tile surfaces including the thickness of conidiophores, the length of spore chains, and the shape of spores. The spores were found to be released continuously during each 30-min experiment. However, the release rate was usually highest during the first few minutes of exposure to air currents and mechanical vibration. About 71-88% of the spores released during a 30-min interval became airborne during the first 10min. (Author)

  9. Model simulations of fungal spore distribution over the Indian region

    Science.gov (United States)

    Ansari, Tabish U.; Valsan, Aswathy E.; Ojha, N.; Ravikrishna, R.; Narasimhan, Balaji; Gunthe, Sachin S.

    2015-12-01

    Fungal spores play important role in the health of humans, animals, and plants by constituting a class of the primary biological aerosol particles (PBAPs). Additionally, these could mediate the hydrological cycle by acting as nuclei for ice and cloud formation (IN and CCN respectively). Various processes in the biosphere and the variations in the meteorological conditions control the releasing mechanism of spores through active wet and dry discharge. In the present paper, we simulate the concentration of fungal spores over the Indian region during three distinct meteorological seasons by combining a numerical model (WRF-Chem) with the fungal spore emissions based on land-use type. Maiden high-resolution regional simulations revealed large spatial gradient and strong seasonal dependence in the concentration of fungal spores over the Indian region. The fungal spore concentrations are found to be the highest during winter (0-70 μg m-3 in December), moderately higher during summer (0-35 μg m-3 in May) and lowest during the monsoon (0-25 μg m-3 in July). The elevated concentrations during winter are attributed to the shallower boundary layer trapping the emitted fungal spores in smaller volume. In contrast, the deeper boundary layer mixing in May and stronger monsoonal-convection in July distribute the fungal spores throughout the lower troposphere (∼5 km). We suggest that the higher fungal spore concentrations during winter could have potential health impacts. While, stronger vertical mixing could enable fungal spores to influence the cloud formation during summer and monsoon. Our study provides the first information about the distribution and seasonal variation of fungal spores over the densely populated and observationally sparse Indian region.

  10. Germination and outgrowth of spores of Bacillus cereus group members: diversity and role of germinant receptors.

    Science.gov (United States)

    Abee, Tjakko; Groot, Masja Nierop; Tempelaars, Marcel; Zwietering, Marcel; Moezelaar, Roy; van der Voort, Menno

    2011-04-01

    Bacillus cereus is a gram-positive, facultative anaerobic, endospore-forming toxicogenic human pathogen. Endospores are highly specialized, metabolically dormant cell types that are resistant to extreme environmental conditions, including heat, dehydration and other physical stresses. B. cereus can enter a range of environments, and can in its spore form, survive harsh conditions. If these conditions become favorable, spores can germinate and grow out and reach considerable numbers in a range of environments including processed foods. Certainly the last decade, when consumer preferences have shifted to mildly processed food, new opportunities arose for spore-forming spoilage and pathogenic organisms. Only rigorous methods have been shown to be capable of destroying all spores present in food, thus a shift toward e.g., milder heat preservation strategies, may result in low but significant amounts of viable spores in food products. Hence, the need for a mild spore destruction strategy is eminent including control of spore outgrowth. Consequently, there is a large interest in triggering spore germination in foodstuffs, since germinated spores have lost the extreme resistance of dormant spores and are relatively easy to kill. Another option could be to prevent germination so that no dangerous levels can be reached. This contribution will focus on germination and outgrowth characteristics of B. cereus and other members of the B. cereus group, providing an overview of the niches these spore-formers can occupy, the signals that trigger germination, and how B. cereus copes with these wake-up calls in different environments including foods, during food processing and upon interaction with the human host.

  11. Role of YpeB in Cortex Hydrolysis during Germination of Bacillus anthracis Spores

    OpenAIRE

    2014-01-01

    The infectious agent of the disease anthrax is the spore of Bacillus anthracis. Bacterial spores are extremely resistant to environmental stresses, which greatly hinders spore decontamination efforts. The spore cortex, a thick layer of modified peptidoglycan, contributes to spore dormancy and resistance by maintaining the low water content of the spore core. The cortex is degraded by germination-specific lytic enzymes (GSLEs) during spore germination, rendering the cells vulnerable to common ...

  12. Heat-induced oxidative injury contributes to inhibition of Botrytis cinerea spore germination and growth.

    Science.gov (United States)

    Zhao, Wei; Wisniewski, Michael; Wang, Wenjie; Liu, Jia; Liu, Yongsheng

    2014-03-01

    The inhibitory effect of heat treatment (HT) on Botrytis cinerea, a major postharvest fungal pathogen, and the possible mode of action were investigated. Spore germination and germ tube elongation of B. cinerea were both increasingly and significantly inhibited by HT (43 °C) for 10, 20 or 30 min. HT-induced gene expression of NADPH oxidase A, resulted in the intracellular accumulation of reactive oxygen species. HT-treated B. cinerea spores exhibited higher levels of oxidative damage to proteins and lipids, compared to the non-HT control. These findings indicate that HT resulted in oxidative damage which then played an important role in the inhibitory effect on B. cinerea. In the current study, HT was effective in controlling gray mold, caused by B. cinerea, in pear fruits. Understanding the mode of action by which HT inhibits fungal pathogens will help in the application of HT for management of postharvest fungal diseases of fruits and vegetables.

  13. 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.

  14. Alicyclobacillus acidoterrestris: new methods for inhibiting spore germination.

    Science.gov (United States)

    Bevilacqua, A; Sinigaglia, M; Corbo, M R

    2008-07-15

    For a long period the thermal processing has been considered as the only way to reduce the initial spore number of Alicyclobacillus acidoterrestris and prevent the spoilage of acidic beverage. New methods, however, were proposed by the literature to control spore germination both in laboratory media and in real systems. After a brief introduction on the impact of A. acidoterrestris in food microbiology and a description of enumeration methods and heat processing applied by the juices manufactures, a review of innovative approaches to inhibit and/or control spore germination is proposed. In particular, this paper focuses on two different topics; the 1st is the use of some natural compounds (monolaurin, lysozyme, nisin and essential oils) or some chemicals, conventional (like sodium-benzoate, organic acids, surfactants and chlorine dioxide) or not conventional (chlorine dioxide as gas). The 2nd topic is a description of some innovative methods to reduce the initial spore number (high hydrostatic and homogenisation pressures, radiation and microwaves).

  15. Characteristics of spore germination and protonemal development in Hypnum pacleseens

    Institute of Scientific and Technical Information of China (English)

    HUANG Shiliang; LI Min; ZHAO Jiancheng; ZHANG Yuanming; WANG Zhenjie

    2006-01-01

    The spore germination,protonemal development,and gametophyte differentiation of Hypnum pacleseens were observed in cultivation.Photomicrographs showed that spore germination of Hypnum pacleseens occured within the exospore.Its protonema is massive with filamentous chloronema formed inside.The terminal part of the chloronema differentiated into filamentous caulonema and its rhizoid was derived from the apical cell of the filamentous chloronema.The initial cell of gametophyte differentiated from chloronema and caulonema.Sporeling type of Hypnum pacleseens is developmentally similar to Glyphmitrium-type.

  16. Hydrolysis of cortex peptidoglycan during bacterial spore germination.

    Science.gov (United States)

    Makino, Shio; Moriyama, Ryuichi

    2002-06-01

    Despite the most extreme dormancy and resistance properties among living systems, bacterial endospores retain an alert sensory mechanism to respond to the germinants and initiate germination. Although the molecular mechanism of the germination process is not completely described, current progress in the studies on the enzymes involved in the process gave us a somewhat clearer picture of the process of spore peptidoglycan (cortex) hydrolysis, a major biochemical event in germination. Germination-specific cortex-lytic enzymes require muramic acid d-lactam in their substrates. At least two types of enzymes are involved in the germination process: a spore cortex-lytic enzyme (SCLE) and a cortical fragment-lytic enzyme (CFLE). Except for their peptidoglycan-binding regions, the primary structures of SCLE and CFLE vary according species. Both enzymes differ in their hydrolytic bond-specificities and recognition of the substrates morphology. SCLE appears to initiate germination by uncrosslinking the intract cortex, and the CFLE further degrades the polysaccharide moiety of the SCLE-modified cortex. In vivo CFLE activity is likely regulated by its requirement for partially un-crosslinked cortex, while SCLE requires activation process. Clostridium perfringens SCLE is activated by a germination-specific serine protease during germination, but the activation mechanism of SCLE in Bacillus species is unknown. Cortex-lytic enzymes are expressed at the early stage of sporulation but the compartment of expression depends on proteins. However, all enzymes are located outside the cortex layer in dormant spores, suggesting that the hydrolysis process initiates at the exterior side of the cortex. The assembly of the germination apparatus is also discussed.

  17. Does proximity to neighbours affect germination of spores of non-proteolytic Clostridium botulinum?

    Science.gov (United States)

    Webb, Martin D; Stringer, Sandra C; Le Marc, Yvan; Baranyi, József; Peck, Michael W

    2012-10-01

    It is recognised that inoculum size affects the rate and extent of bacterial spore germination. It has been proposed that this is due to spores interacting: molecules released from germinated spores trigger germination of dormant neighbours. This study investigated whether changes to the total number of spores in a system or proximity to other spores (local spore density) had a more significant effect on interaction between spores of non-proteolytic Clostridium botulinum strain Eklund 17B attached to defined areas of microscope slides. Both the number of spores attached to the slides and local spore density (number of spores per mm(2)) were varied by a factor of nine. Germination was observed microscopically at 15 °C for 8 h and the probability of, and time to, germination calculated from image analysis measurements. Statistical analysis revealed that the effect of total spore number on the probability of germination within 8 h was more significant than that of proximity to neighbours (local spore density); its influence on germination probability was approximately four-times greater. Total spore number had an even more significant affect on time to germination; it had a nine-fold greater influence than proximity to neighbours. The applied models provide a means to characterise, quantitatively, the effect of the total spore number on spore germination relative to the effect of proximity to neighbouring spores.

  18. Ribosomal ribonucleic acid maturation during bacterial spore germination.

    Science.gov (United States)

    Bleyman, M; Woese, C

    1969-01-01

    All the ribosomal ribonucleic acid made during the early stages of germination of spores of Bacillus subtilis is of the "precursor" type, i.e., that type appearing in the incomplete forms of the ribosome. Shortly before the onset of deoxyribonucleic acid synthesis in germination, this precursor ribonucleic acid changed to the mature ribosomal ribonucleic acid characteristic of the 30S and 50S ribosomal subunits.

  19. Determination of fungal spore release from wet building materials

    DEFF Research Database (Denmark)

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

    2003-01-01

    of fungal spores was induced by well-defined jets of air impacting from rotating nozzles. The spores and other particles released from the surface were transported by the air flowing from the chamber through a top outlet to a particle counter and sizer. For two of the fungi (Penicillium chrysogenum...... and Trichoderma harzianum ), the number of spores produced on the gypsum board and subsequently released was quantified. Also the relationship between air velocities from 0.3 to 3 m/s over the surface and spore release has been measured. The method was found to give very reproducible results for each fungal...... isolate, whereas the spore release is very different for different fungi under identical conditions. Also, the relationship between air velocity and spore release depends on the fungus. For some fungi a significant number of particles smaller than the spore size were released. The method applied...

  20. Thirty-four identifiable airborne fungal spores in Havana, Cuba

    Directory of Open Access Journals (Sweden)

    Michel Almaguer

    2015-05-01

    Full Text Available The airborne fungal spore content in Havana, Cuba, collected by means a non-viable volumetric methodology, was studied from November 2010 – October 2011. The study, from a qualitative point of view, allowed the characterization of 29 genera and 5 fungal types, described following the Saccardo´s morphotypes, as well as their morphobiometrical characteristics. In the amerospores morphotype, the conidia of 7 genera (with ascospores, basidiospores and uredospores and 5 fungal types were included. Among phragmospores morphotype, the ascospores and conidia of 12 different genera were identified. The dictyospores morphotype only included conidial forms from 6 genera. Finally, the less frequent morphotypes were staurospores, didymospores and distosepted spores. In general, the main worldwide spread mitosporic fungi also predominated in the Havana atmosphere, accompanied by some ascospores and basidiospores. [i]Cladosporium[/i] cladosporioides type was the most abundant with a total of 148,717 spores, followed by [i]Leptosphaeria, Coprinus[/i] and the [i]Aspergillus-Penicillium [/i]type spores, all of them with total values ranging from 20,591 – 16,392 spores. The higher monthly concentrations were registered in January (31,663 spores and the lowest in December (7,314 spores. Generally, the average quantity of spores recorded during the months of the dry season (20,599 spores was higher compared with that observed during the rainy season (17,460 spores.

  1. Thirty-four identifiable airborne fungal spores in Havana, Cuba

    Directory of Open Access Journals (Sweden)

    Michel Almaguer

    2015-05-01

    Full Text Available The airborne fungal spore content in Havana, Cuba, collected by means a non-viable volumetric methodology, was studied from November 2010 – October 2011. The study, from a qualitative point of view, allowed the characterization of 29 genera and 5 fungal types, described following the Saccardo´s morphotypes, as well as their morphobiometrical characteristics. In the amerospores morphotype, the conidia of 7 genera (with ascospores, basidiospores and uredospores and 5 fungal types were included. Among phragmospores morphotype, the ascospores and conidia of 12 different genera were identified. The dictyospores morphotype only included conidial forms from 6 genera. Finally, the less frequent morphotypes were staurospores, didymospores and distosepted spores. In general, the main worldwide spread mitosporic fungi also predominated in the Havana atmosphere, accompanied by some ascospores and basidiospores. Cladosporium cladosporioides type was the most abundant with a total of 148,717 spores, followed by Leptosphaeria, Coprinus and the Aspergillus-Penicillium type spores, all of them with total values ranging from 20,591 – 16,392 spores. The higher monthly concentrations were registered in January (31,663 spores and the lowest in December (7,314 spores. Generally, the average quantity of spores recorded during the months of the dry season (20,599 spores was higher compared with that observed during the rainy season (17,460 spores.

  2. Thirty-four identifiable airborne fungal spores in Havana, Cuba.

    Science.gov (United States)

    Almaguer, Michel; Aira, María-Jesús; Rodríguez-Rajo, F Javier; Fernandez-Gonzalez, Maria; Rojas-Flores, Teresa I

    2015-01-01

    The airborne fungal spore content in Havana, Cuba, collected by means a non-viable volumetric methodology, was studied from November 2010 - October 2011. The study, from a qualitative point of view, allowed the characterization of 29 genera and 5 fungal types, described following the Saccardo´s morphotypes, as well as their morphobiometrical characteristics. In the amerospores morphotype, the conidia of 7 genera (with ascospores, basidiospores and uredospores) and 5 fungal types were included. Among phragmospores morphotype, the ascospores and conidia of 12 different genera were identified. The dictyospores morphotype only included conidial forms from 6 genera. Finally, the less frequent morphotypes were staurospores, didymospores and distosepted spores. In general, the main worldwide spread mitosporic fungi also predominated in the Havana atmosphere, accompanied by some ascospores and basidiospores. Cladosporium cladosporioides type was the most abundant with a total of 148,717 spores, followed by Leptosphaeria, Coprinus and the Aspergillus-Penicillium type spores, all of them with total values ranging from 20,591 - 16,392 spores. The higher monthly concentrations were registered in January (31,663 spores) and the lowest in December (7,314 spores). Generally, the average quantity of spores recorded during the months of the dry season (20,599 spores) was higher compared with that observed during the rainy season (17,460 spores).

  3. 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

  4. 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

  5. Determination of fungal spore release from wet building materials.

    Science.gov (United States)

    Kildesø, J; Würtz, H; Nielsen, K F; Kruse, P; Wilkins, K; Thrane, U; Gravesen, S; Nielsen, P A; Schneider, T

    2003-06-01

    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 of typical indoor fungi has been measured under controlled conditions. The fungi were cultivated for a period of 4-6 weeks on sterilized wet wallpapered gypsum boards at a relative humidity (RH) of approximately 97%. A specially designed small chamber (P-FLEC) was placed on the gypsum board. The release of fungal spores was induced by well-defined jets of air impacting from rotating nozzles. The spores and other particles released from the surface were transported by the air flowing from the chamber through a top outlet to a particle counter and sizer. For two of the fungi (Penicillium chrysogenum and Trichoderma harzianum), the number of spores produced on the gypsum board and subsequently released was quantified. Also the relationship between air velocities from 0.3 to 3 m/s over the surface and spore release has been measured. The method was found to give very reproducible results for each fungal isolate, whereas the spore release is very different for different fungi under identical conditions. Also, the relationship between air velocity and spore release depends on the fungus. For some fungi a significant number of particles smaller than the spore size were released. The method applied in the study may also be useful for field studies and for generation of spores for exposure studies.

  6. At-line determining spore germination of Penicillium chrysogenum bioprocesses in complex media.

    Science.gov (United States)

    Ehgartner, Daniela; Fricke, Jens; Schröder, Andreas; Herwig, Christoph

    2016-10-01

    Spore inoculum quality in filamentous bioprocesses is a critical parameter associated with viable spore concentration (1) and spore germination (2). It influences pellet morphology and, consequently, process performance. The state-of-the-art method to measure viable spore concentration is tedious, associated with significant inherent bias, and not applicable in real-time. Therefore, it is not usable as process analytical technology (PAT). Spore germination has so far been monitored using image analysis, which is hampered by complex medium background often observed in filamentous bioprocesses. The method presented here is based on the combination of viability staining and large-particle flow cytometry which enables measurements in real-time and hence aims to be applicable as a PAT tool. It is compatible with the complex media background and allows the quantification of metabolically active spores and the monitoring of spore germination. A distinction of germinated spores and not germinated spores was based on logistic regression, using multiparameteric data from flow cytometry. In a first step, a significant correlation between colony-forming unit (CFU) counts and viable spore concentration (1) in an industrially relevant model bioprocess was found. Spore germination (2) was followed over the initial process phase with close temporal resolution. The validation of the method showed an error below 5 %. Differences in spore germination for various spore inocula ages and spore inoculum concentrations were monitored. The real-time applicability of the method suggests the implementation as a PAT tool in filamentous bioprocesses.

  7. Spore germination and germinant receptor genes in wild strains of Bacillus subtilis.

    Science.gov (United States)

    Alzahrani, O M; Moir, A

    2014-09-01

    To compare the germination of laboratory and wild strains of Bacillus subtilis. The spore germination of B. subtilis 168 (subsp. subtilis) was compared with that of the laboratory strain W23 (subsp. spizizenii) and desert-sourced isolates, including one member of subsp. subtilis (RO-NN-1), strains TU-B-10, RO-E-2, N10 and DV1-B-1, (all subsp. spizizenii), the B. mojavensis strain RO-H-1 and a B. subtilis natto strain. All germinated in L-alanine, although some were slower, and some 10-fold less sensitive to germinant. All germinated in calcium dipicolinate (CaDPA). Germination in asparagine, glucose, fructose + KCl was slow and incomplete in many of the strains, and decoating RO-NN-1 and W23 spores did not restore germination rates. Comparing the sequences of B. subtilis strains 168, RO-NN-1, W23, TU-B-10 and DV1-B-1, the operons encoding GerA, B and K germinant receptors were intact, although the two additional operons yndDEF and yfkQRST had suffered deletions or were absent in several spizizenii strains. Wild strains possess an efficient germination machinery for L-alanine germination. AGFK germination is often less efficient, the gerB genes more diverged, and the two germinant receptor operons of unknown function have been lost from the genome in many subsp. spizizenii strains. The two major subspecies of B. subtilis have conserved GerA receptor function, confirming its importance, at least in the natural environments of these strains. © 2014 The Society for Applied Microbiology.

  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. Involvement of Coat Proteins in Bacillus subtilis Spore Germination in High-Salinity Environments.

    Science.gov (United States)

    Nagler, Katja; Setlow, Peter; Reineke, Kai; Driks, Adam; Moeller, Ralf

    2015-10-01

    The germination of spore-forming bacteria in high-salinity environments is of applied interest for food microbiology and soil ecology. It has previously been shown that high salt concentrations detrimentally affect Bacillus subtilis spore germination, rendering this process slower and less efficient. The mechanistic details of these salt effects, however, remained obscure. Since initiation of nutrient germination first requires germinant passage through the spores' protective integuments, the aim of this study was to elucidate the role of the proteinaceous spore coat in germination in high-salinity environments. Spores lacking major layers of the coat due to chemical decoating or mutation germinated much worse in the presence of NaCl than untreated wild-type spores at comparable salinities. However, the absence of the crust, the absence of some individual nonmorphogenetic proteins, and the absence of either CwlJ or SleB had no or little effect on germination in high-salinity environments. Although the germination of spores lacking GerP (which is assumed to facilitate germinant flow through the coat) was generally less efficient than the germination of wild-type spores, the presence of up to 2.4 M NaCl enhanced the germination of these mutant spores. Interestingly, nutrient-independent germination by high pressure was also inhibited by NaCl. Taken together, these results suggest that (i) the coat has a protective function during germination in high-salinity environments; (ii) germination inhibition by NaCl is probably not exerted at the level of cortex hydrolysis, germinant accessibility, or germinant-receptor binding; and (iii) the most likely germination processes to be inhibited by NaCl are ion, Ca(2+)-dipicolinic acid, and water fluxes.

  10. Surface Hydrophobicity and Surface Rigidity Induce Spore Germination in Colletotrichum graminicola.

    Science.gov (United States)

    Chaky, J; Anderson, K; Moss, M; Vaillancourt, L

    2001-06-01

    ABSTRACT We investigated the relationship between physical characteristics of artificial surfaces, spore attachment, and spore germination in Colletotrichum graminicola. Surface hydrophobicity and surface rigidity were both signals for breaking dormancy and initiating spore germination, but spore attachment alone was not an important inducing signal. The presence of a carbon source overrode the necessity for a rigid, hydrophobic substrate for spore germination. Spore attachment was typically stronger to more hydrophobic surfaces, but certain hydrophilic surfaces also proved to be good substrates for spore attachment. In contrast to spore germination, appressorial induction was more dependent on attachment to a rigid substrate than it was on surface hydrophobicity. Appressoria were induced efficiently on hydrophilic surfaces, as long as there was significant conidial attachment to those surfaces.

  11. Dipicolinic Acid Release by Germinating Clostridium difficile Spores Occurs through a Mechanosensing Mechanism

    Science.gov (United States)

    Francis, Michael B.

    2016-01-01

    ABSTRACT Classically, dormant endospores are defined by their resistance properties, particularly their resistance to heat. Much of the heat resistance is due to the large amount of dipicolinic acid (DPA) stored within the spore core. During spore germination, DPA is released and allows for rehydration of the otherwise-dehydrated core. In Bacillus subtilis, 7 proteins are encoded by the spoVA operon and are important for DPA release. These proteins receive a signal from the activated germinant receptor and release DPA. This DPA activates the cortex lytic enzyme CwlJ, and cortex degradation begins. In Clostridium difficile, spore germination is initiated in response to certain bile acids and amino acids. These bile acids interact with the CspC germinant receptor, which then transfers the signal to the CspB protease. Activated CspB cleaves the cortex lytic enzyme, pro-SleC, to its active form. Subsequently, DPA is released from the core. C. difficile encodes orthologues of spoVAC, spoVAD, and spoVAE. Of these, the B. subtilis SpoVAC protein was shown to be capable of mechanosensing. Because cortex degradation precedes DPA release during C. difficile spore germination (opposite of what occurs in B. subtilis), we hypothesized that cortex degradation would relieve the osmotic constraints placed on the inner spore membrane and permit DPA release. Here, we assayed germination in the presence of osmolytes, and we found that they can delay DPA release from germinating C. difficile spores while still permitting cortex degradation. Together, our results suggest that DPA release during C. difficile spore germination occurs though a mechanosensing mechanism. IMPORTANCE Clostridium difficile is transmitted between hosts in the form of a dormant spore, and germination by C. difficile spores is required to initiate infection, because the toxins that are necessary for disease are not deposited on the spore form. Importantly, the C. difficile spore germination pathway

  12. Palynological investigation of the sediment cores from the Arabian Sea 1 Fungal spores

    Digital Repository Service at National Institute of Oceanography (India)

    Chandra, A.; Saxena, R.K.; Setty, M.G.A.P.

    The paper deals with the systematic study of the fungal spores recovered from five sediment cores from the Arabian Sea The fungal spore assemblage recorded here includes 12 genera viz., @iInapertisporites, Dicellaesporites, Multicellaesporites...

  13. Ambient pH stress inhibits spore germination of Penicillium expansum by impairing protein synthesis and folding: a proteomic-based study.

    Science.gov (United States)

    Li, Boqiang; Lai, Tongfei; Qin, Guozheng; Tian, Shiping

    2010-01-01

    Spore germination is the first step for fungal pathogens to infect host plants. The pH value, as one of the most important environmental parameters, has critical influence on spore germination. In this study, effects of ambient pH on spore germination were determined by culturing spores of Penicillium expansum in medium with pH values at 2.0, 5.0 and 8.0, and involved mechanisms were further investigated through methods of comparative proteomics. The results demonstrated that spore germination of P. expansum was obviously inhibited at pH 2.0 and 8.0. Using quadrupole time-of-flight tandem mass spectrometer, 34 proteins with significant changes in abundance were identified. Among them, 17 proteins were related to protein synthesis and folding, and most of them were down-regulated at pH 2.0 and 8.0. Accordingly, lower content of total soluble proteins and higher ratio of aggregated proteins were observed in spores at pH 2.0 and 8.0. In addition, it was found that ambient pH could affect intracellular pH and ATP level of P. expansum spores. These findings indicated that ambient pH might affect spore germination of P. expansum by changing intracellular pH and regulating protein expression. Further, impairing synthesis and folding of proteins might be one of the main reasons.

  14. 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

  15. Removal of pyrimidine dimers in UV-irradiated spores of Dictyostelium discoideum during germination

    Energy Technology Data Exchange (ETDEWEB)

    Okaichi, K.; Tano, K.; Ohnishi, T.; Nozu, K.

    1985-06-01

    The spores of Dictyostelium discoideum TW-8 (radC) are about twice as sensitive to UV than the parental strain NC-4 spores at a 10% survival level. Ultraviolet irradiation apparently suppressed the emergence of amoebae from swollen TW-8 spores as compared with NC-4 spores, though the conversion of spores into swollen spores was not affected by UV irradiation in either strain. About 85% removal of pyrimidine dimers was detected in UV-irradiated NC-4 spores at 200 J/m/sup 2/ during spore germination for 9 h, but no removal of pyrimidine dimers was detected in TW-8 spores under the same conditions. The removal of pyrimidine dimers from the NC-4 spores began at around 2 h germination when the spores have become swollen. The number of enzyme-sensitive sites (ESS) detected by Micrococcus luteus endonuclease in the DNA of UV-irradiated NC-4 spores also began to decrease at about 2 h into germination. The decrease in ESS, however, was hardly detectable in UV-irradiated TW-8 spores at any step during germination. Cycloheximide inhibited both decrease in the number of pyrimidine dimers, and decrease in the number of ESS of UV-irradiated NC-4 spores. It is suggested that UV-specific endonuclease is newly synthesized in swollen spores of NC-4. (author).

  16. Glycerol enhances fungal germination at the water-activity limit for life.

    OpenAIRE

    Stevenson, Andrew; Hamill, Philip G.; Medina, Ángel; Kminek, Gerhard; Rummel, John D.; Dijksterhuis, Jan; Timson, David; MAGAN, Naresh; Leong, Su-lin L.; Hallsworth, John

    2016-01-01

    For the most-extreme fungal xerophiles, metabolic activity and cell division typically halts between 0.700 and 0.640 water activity (approximately 70.0-64.0% relative humidity). Here, we investigate whether glycerol can enhance xerophile germination under acute water-activity regimes, using an experimental system which represents the biophysical limit of Earth's biosphere. Spores of a variety of species including Aspergillus penicillioides, Eurotium halophilicum, Xerochrysium xerophilium (for...

  17. Spore germination of Trichoderma atroviride is inhibited by its LysM protein TAL6.

    Science.gov (United States)

    Seidl-Seiboth, Verena; Zach, Simone; Frischmann, Alexa; Spadiut, Oliver; Dietzsch, Christian; Herwig, Christoph; Ruth, Claudia; Rodler, Agnes; Jungbauer, Alois; Kubicek, Christian P

    2013-03-01

    LysM motifs are carbohydrate-binding modules found in prokaryotes and eukaryotes. They have general N-acetylglucosamine binding properties and therefore bind to chitin and related carbohydrates. In plants, plasma-membrane-bound proteins containing LysM motifs are involved in plant defence responses, but also in symbiotic interactions between plants and microorganisms. Filamentous fungi secrete LysM proteins that contain several LysM motifs but no enzymatic modules. In plant pathogenic fungi, for LysM proteins roles in dampening of plant defence responses and protection from plant chitinases were shown. In this study, the carbohydrate-binding specificities and biological function of the LysM protein TAL6 from the plant-beneficial fungus Trichoderma atroviride were investigated. TAL6 contains seven LysM motifs and the sequences of its LysM motifs are very different from other fungal LysM proteins investigated so far. The results showed that TAL6 bound to some forms of polymeric chitin, but not to chito-oligosaccharides. Further, no binding to fungal cell wall preparations was detected. Despite these rather weak carbohydrate-binding properties, a strong inhibitory effect of TAL6 on spore germination was found. TAL6 was shown to specifically inhibit germination of Trichoderma spp., but interestingly not of other fungi. Thus, this protein is involved in self-signalling processes during fungal growth rather than fungal-plant interactions. These data expand the functional repertoire of fungal LysM proteins beyond effectors in plant defence responses and show that fungal LysM proteins are also involved in the self-regulation of fungal growth and development. © 2013 The Authors Journal compilation © 2013 FEBS.

  18. Deoxyribonucleic acid synthesis and deoxynucleotide metabolism during bacterial spore germination.

    Science.gov (United States)

    Setlow, P

    1973-06-01

    Deoxyribonucleic acid (DNA) synthesis during germination of Bacillus megaterium spores takes place in two stages. In stage I (0-55 min) DNA synthesis is slow and there is no detectable net synthesis, whereas in stage II (from 55 min on) the rate of synthesis is much faster and net DNA synthesis occurs. Deoxyribonucleotide pool sizes match the rates of DNA synthesis in stages I and II. The level of deoxyribonucleotide triphosphates is not correlated with the level of deoxyribonucleotide kinases, but rather with that of ribonucleotide reductase activity.

  19. In vitro high-resolution structural dynamics of single germinating bacterial spores

    Energy Technology Data Exchange (ETDEWEB)

    Plomp, M; Leighton, T; Wheeler, K; Malkin, A

    2006-11-14

    Although significant progress has been achieved in understanding the genetic and biochemical bases of the spore germination process, the structural basis for breaking the dormant spore state remains poorly understood. We have used atomic force microscopy (AFM) to probe the high-resolution structural dynamics of single Bacillus atrophaeus spores germinating under native conditions. Here we show that AFM can reveal previously unrecognized germination-induced alterations in spore coat architecture and topology as well as the disassembly of outer spore coat rodlet structures. These results and previous studies in other microorganisms suggest that the spore coat rodlets are structurally similar to amyloid fibrils. AFM analysis of the nascent surface of the emerging germ cell revealed a porous network of peptidoglycan fibers. The results are consistent with a honeycomb model structure for synthetic peptidoglycan oligomers determined by nuclear magnetic resonance. AFM is a promising experimental tool for investigating the morphogenesis of spore germination and cell wall peptidoglycan structure.

  20. In vitro high-resolution structural dynamics of single germinating bacterial spores

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence Livermore National Laboratory

    2006-12-11

    Although significant progress has been achieved in understanding the genetic and biochemical bases of the spore germination process, the structural basis for breaking the dormant spore state remains poorly understood. We have used atomic force microscopy (AFM) to probe the high-resolution structural dynamics of single Bacillus atrophaeus spores germinating under native conditions. Here we show that AFM can reveal previously unrecognized germination-induced alterations in spore coat architecture and topology as well as the disassembly of outer spore coat rodlet structures. These results and previous studies in other microorganisms suggest that the spore coat rodlets are structurally similar to amyloid fibrils. AFM analysis of the nascent surface of the emerging germ cell revealed a porous network of peptidoglycan fibers. The results are consistent with a honeycomb model structure for synthetic peptidoglycan oligomers determined by nuclear magnetic resonance. AFM is a promising experimental tool for investigating the morphogenesis of spore germination and cell wall peptidoglycan structure.

  1. Characterization of bacterial spore germination using integrated phase contrast microscopy, Raman spectroscopy, and optical tweezers.

    Science.gov (United States)

    Kong, Lingbo; Zhang, Pengfei; Setlow, Peter; Li, Yong-Qing

    2010-05-01

    We present a methodology that combines external phase contrast microscopy, Raman spectroscopy, and optical tweezers to monitor a variety of changes during the germination of single Bacillus cereus spores in both nutrient (l-alanine) and non-nutrient (Ca-dipicolinic acid (DPA)) germinants with a temporal resolution of approximately 2 s. Phase contrast microscopy assesses changes in refractility of individual spores during germination, while Raman spectroscopy gives information on changes in spore-specific molecules. The results obtained include (1) the brightness of the phase contrast image of an individual dormant spore is proportional to the level of CaDPA in that spore; (2) the end of the first Stage of germination, revealed as the end of the rapid drop in spore refractility by phase contrast microscopy, precisely corresponds to the completion of the release of CaDPA as revealed by Raman spectroscopy; and (3) the correspondence between the rapid drop in spore refractility and complete CaDPA release was observed not only for spores germinating in the well-controlled environment of an optical trap but also for spores germinating when adhered on a microscope coverslip. Using this latter method, we also simultaneously characterized the distribution of the time-to-complete-CaDPA release (T(release)) of hundreds of individual B. cereus spores germinating with both saturating and subsaturating concentrations of l-alanine and with CaDPA.

  2. Role of dipicolinic acid in the germination, stability, and viability of spores of Bacillus subtilis.

    Science.gov (United States)

    Magge, Anil; Granger, Amanda C; Wahome, Paul G; Setlow, Barbara; Vepachedu, Venkata R; Loshon, Charles A; Peng, Lixin; Chen, De; Li, Yong-Qing; Setlow, Peter

    2008-07-01

    Spores of Bacillus subtilis spoVF strains that cannot synthesize dipicolinic acid (DPA) but take it up during sporulation were prepared in medium with various DPA concentrations, and the germination and viability of these spores as well as the DPA content in individual spores were measured. Levels of some other small molecules in DPA-less spores were also measured. These studies have allowed the following conclusions. (i) Spores with no DPA or low DPA levels that lack either the cortex-lytic enzyme (CLE) SleB or the receptors that respond to nutrient germinants could be isolated but were unstable and spontaneously initiated early steps in spore germination. (ii) Spores that lacked SleB and nutrient germinant receptors and also had low DPA levels were more stable. (iii) Spontaneous germination of spores with no DPA or low DPA levels was at least in part via activation of SleB. (iv) The other redundant CLE, CwlJ, was activated only by the release of high levels of DPA from spores. (v) Low levels of DPA were sufficient for the viability of spores that lacked most alpha/beta-type small, acid-soluble spore proteins. (vi) DPA levels accumulated in spores prepared in low-DPA-containing media varied greatly between individual spores, in contrast to the presence of more homogeneous DPA levels in individual spores made in media with high DPA concentrations. (vii) At least the great majority of spores of several spoVF strains that contained no DPA also lacked other major spore small molecules and had gone through some of the early reactions in spore germination.

  3. Spore swelling and germination as a bioassay for the rapid screening of crude biological extracts for antifungal activity.

    Science.gov (United States)

    Uldahl, Svein Atle; Knutsen, Gjert

    2009-10-01

    Screening for bioactivity is commonly performed in vivo in a bioassay purposefully designed for revealing a defined bioactivity (e.g. fungicide or antibacterial activity). This allows the testing of many crude extracts. In the present work a new method (bioassay) targeting spore swelling and germination to assess antifungal susceptibility is developed and evaluated. Traditionally, antifungal activity has been investigated using disk diffusion assays or micro-well plates. Inhibition is measured as a function of radial growth, inhibition zone or turbidity. The construction of a bioassay composed of germinating fungal spores bears the prospect of being a more rapid method, allowing more extracts to be screened within a shorter time frame. It can also be used to reveal antifungal action at an early state in the prospecting process. Suppression of spore swelling provides early indication of inhibitory potential and the type of swelling curve produced might indicate the mechanism of fungistasis. A strain of Absidia glauca Hagem served as model organism. A Beckman Coulter Multiziser 3 particle analyser was applied for the determination of bioactivity and investigation of the sporangiospores. Inhibition was standardized against two known fungicides (sorbic and benzoic acid). Four biological extract solvents were also tested; where DMSO was found to be the best candidate as extract solvent in the assay. Inhibition was investigated as changes in volumes of the germinating spores using germination as endpoint target. The new bioassay was found to be a simple and rapid method for detection of antifungal activity of extracts.

  4. 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.

  5. Efficient transformation of Rhizopus delemar by electroporation of germinated spores.

    Science.gov (United States)

    Xu, Sha; Zhou, Zhengxiong; Du, Guocheng; Zhou, Jingwen; Chen, Jian

    2014-08-01

    High efficient transformation of mycelial fungi is essential to both metabolic engineering and physiological analysis of these industrially important microorganisms. However, transformation efficiencies for mycelial fungi are highly restricted by difficulties in colony formation and competent cell preparation. In this work, an innovative transformation procedure that could significantly improve the efficiency of colony formation and transformation process has been established for a typical mycelial fungus, Rhizopus delemar. Single colonies of R. delemar were obtained with the addition of sodium deoxycholate. Fresh germinated spores of R. delemar were successfully transformed by electroporation. In addition, by pretreatment of the germinated spores with 0.05M lithium acetate (LiAc) and 20mM dithiothreitol (DTT) before electroporation, the transformation efficiency was further improved by 9.5-fold. The final transformation efficiency at optimal conditions reached 1239 transformants/μg DNA. The method described here would facilitate more efficient metabolic engineering and investigation of physiological functions in R. delemar or other similar mycelial fungi.

  6. Fungal Spores Viability on the International Space Station.

    Science.gov (United States)

    Gomoiu, I; Chatzitheodoridis, E; Vadrucci, S; Walther, I; Cojoc, R

    2016-11-01

    In this study we investigated the security of a spaceflight experiment from two points of view: spreading of dried fungal spores placed on the different wafers and their viability during short and long term missions on the International Space Station (ISS). Microscopic characteristics of spores from dried spores samples were investigated, as well as the morphology of the colonies obtained from spores that survived during mission. The selected fungal species were: Aspergillus niger, Cladosporium herbarum, Ulocladium chartarum, and Basipetospora halophila. They have been chosen mainly based on their involvement in the biodeterioration of different substrate in the ISS as well as their presence as possible contaminants of the ISS. From biological point of view, three of the selected species are black fungi, with high melanin content and therefore highly resistant to space radiation. The visual inspection and analysis of the images taken before and after the short and the long term experiments have shown that all biocontainers were returned to Earth without damages. Microscope images of the lids of the culture plates revealed that the spores of all species were actually not detached from the surface of the wafers and did not contaminate the lids. From the adhesion point of view all types of wafers can be used in space experiments, with a special comment on the viability in the particular case of iron wafers when used for spores that belong to B. halophila (halophilic strain). This is encouraging in performing experiments with fungi without risking contamination. The spore viability was lower in the experiment for long time to ISS conditions than that of the short experiment. From the observations, it is suggested that the environment of the enclosed biocontainer, as well as the species'specific behaviour have an important effect, reducing the viability in time. Even the spores were not detached from the surface of the wafers, it was observed that spores used in the

  7. Fungal Spores Viability on the International Space Station

    Science.gov (United States)

    Gomoiu, I.; Chatzitheodoridis, E.; Vadrucci, S.; Walther, I.; Cojoc, R.

    2016-04-01

    In this study we investigated the security of a spaceflight experiment from two points of view: spreading of dried fungal spores placed on the different wafers and their viability during short and long term missions on the International Space Station (ISS). Microscopic characteristics of spores from dried spores samples were investigated, as well as the morphology of the colonies obtained from spores that survived during mission. The selected fungal species were: Aspergillus niger, Cladosporium herbarum, Ulocladium chartarum, and Basipetospora halophila. They have been chosen mainly based on their involvement in the biodeterioration of different substrate in the ISS as well as their presence as possible contaminants of the ISS. From biological point of view, three of the selected species are black fungi, with high melanin content and therefore highly resistant to space radiation. The visual inspection and analysis of the images taken before and after the short and the long term experiments have shown that all biocontainers were returned to Earth without damages. Microscope images of the lids of the culture plates revealed that the spores of all species were actually not detached from the surface of the wafers and did not contaminate the lids. From the adhesion point of view all types of wafers can be used in space experiments, with a special comment on the viability in the particular case of iron wafers when used for spores that belong to B. halophila (halophilic strain). This is encouraging in performing experiments with fungi without risking contamination. The spore viability was lower in the experiment for long time to ISS conditions than that of the short experiment. From the observations, it is suggested that the environment of the enclosed biocontainer, as well as the species'specific behaviour have an important effect, reducing the viability in time. Even the spores were not detached from the surface of the wafers, it was observed that spores used in the

  8. Fungal Spores Viability on the International Space Station

    Science.gov (United States)

    Gomoiu, I.; Chatzitheodoridis, E.; Vadrucci, S.; Walther, I.; Cojoc, R.

    2016-11-01

    In this study we investigated the security of a spaceflight experiment from two points of view: spreading of dried fungal spores placed on the different wafers and their viability during short and long term missions on the International Space Station (ISS). Microscopic characteristics of spores from dried spores samples were investigated, as well as the morphology of the colonies obtained from spores that survived during mission. The selected fungal species were: Aspergillus niger, Cladosporium herbarum, Ulocladium chartarum, and Basipetospora halophila. They have been chosen mainly based on their involvement in the biodeterioration of different substrate in the ISS as well as their presence as possible contaminants of the ISS. From biological point of view, three of the selected species are black fungi, with high melanin content and therefore highly resistant to space radiation. The visual inspection and analysis of the images taken before and after the short and the long term experiments have shown that all biocontainers were returned to Earth without damages. Microscope images of the lids of the culture plates revealed that the spores of all species were actually not detached from the surface of the wafers and did not contaminate the lids. From the adhesion point of view all types of wafers can be used in space experiments, with a special comment on the viability in the particular case of iron wafers when used for spores that belong to B. halophila (halophilic strain). This is encouraging in performing experiments with fungi without risking contamination. The spore viability was lower in the experiment for long time to ISS conditions than that of the short experiment. From the observations, it is suggested that the environment of the enclosed biocontainer, as well as the species'specific behaviour have an important effect, reducing the viability in time. Even the spores were not detached from the surface of the wafers, it was observed that spores used in the

  9. 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.

  10. Effect of Carbon and Nitrogen Availability on Metabolism of Amino Acids in Germinating Spores of Arbuscular Mycorrhizal Fungi

    Institute of Scientific and Technical Information of China (English)

    JIN Hai-Ru; JIANG Dong-Hua; ZHANG Ping-Hua

    2011-01-01

    The effects of carbon (C) and nitrogen (N) sources on N utilization and biosynthesis of amino acids were examined in the germinating spores of the arbuscular mycorrhizal (AM) fungus Glomus intraradices Schenck & Smith after exposure to various N substrates,CO2,glucose,and/or root exudates.The N uptake and de novo biosynthesis of amino acids were analyzed using stable isotopic labeling with mass spectrometric detection.High-performance liquid chromatography-based analysis was used to measure amino acid levels.In the absence of exogenous N sources and in the presence of 25 mL L-1 CO2,the germinating AM fungal spores utilized internal N storage as well as C skeletons derived from the degradation of storage lipids to biosynthesize the free amino acids,in which serine and glycine were produced predominantly.The concentrations of internal amino acids increased gradually as the germination time increased from 0 to 1 or 2 weeks.However,asparagine and glutamine declined to the low levels; both degraded to provide the biosynthesis of other amino acids with C and N donors.The availability of exogenous inorganic N (ammonium and nitrate) and organic N (urea,arginine,and glutamine) to the AM fungal spores using only CO2 for germination generated more than 5 times more internal free amino acids than those in the absence of exogenous N.A supply of exogenous nitrate to the AM fungal spores with only CO2 gave rise to more than 10 times more asparagine than that without exogenous N.In contrast,the extra supply of exogenous glucose to the AM fungal spores generated a significant enhancement in the uptake of exogenous N sources,with more than 3 times more free amino acids being produced than those supplied with only exogenous CO2.Meanwhile,arginine was the most abundant free amino acid produced and it was incorporated into the proteins of AM fungal spores to serve as an N storage compound.

  11. Impact of sorbic acid on germination and outgrowth heterogeneity of Bacillus cereus ATCC 14579 spores

    NARCIS (Netherlands)

    Besten, den H.M.W.; Melis, van C.C.J.; Sanders, J.W.; Nierop Groot, M.N.; Abee, T.

    2012-01-01

    Population heterogeneity complicates the predictability of the outgrowth kinetics of individual spores. Flow cytometry sorting and monitoring of the germination and outgrowth of single dormant spores allowed the quantification of acid-induced spore population heterogeneity at pH 5.5 and in the prese

  12. Ultraweak luminescence from germinating resting spores of Entomophthora virulenta Hall et Dunn

    OpenAIRE

    Janusz Sławiński; Irena Majchrowicz; Edward Grabikowski

    2014-01-01

    Germinating resting spores of Entomophthora virulenta Hall et Dunn emit ultraweak luminescence with the intensity of the order 100 photons • s-1 • cm-2 in the spectral region 200-750 nm. The emission kinetics and intensity depend on vitality and incubation temperature of the spores. The higher the ability of resting spores to germinate, the more intense the luminescence. Elevation of the incubation temperature to 50°C enhances ultraweak luminescence. The activation energy was found to be abou...

  13. A Clostridium difficile-Specific, Gel-Forming Protein Required for Optimal Spore Germination

    Directory of Open Access Journals (Sweden)

    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.

  14. A Clostridium difficile-Specific, Gel-Forming Protein Required for Optimal Spore Germination

    Science.gov (United States)

    Donnelly, M. Lauren; Li, William; Li, Yong-qing; Hinkel, Lauren; Setlow, Peter

    2017-01-01

    ABSTRACT 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. PMID:28096487

  15. 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.

    Science.gov (United States)

    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.

  16. Triggering germination represents a novel strategy to enhance killing of Clostridium difficile spores.

    Directory of Open Access Journals (Sweden)

    Michelle M Nerandzic

    Full Text Available BACKGROUND: Clostridium difficile is an anaerobic, spore-forming bacterium that is the most common cause of healthcare-associated diarrhea in developed countries. Control of C. difficile is challenging because the spores are resistant to killing by alcohol-based hand hygiene products, antimicrobial soaps, and most disinfectants. Although initiation of germination has been shown to increase susceptibility of spores of other bacterial species to radiation and heat, it was not known if triggering of germination could be a useful strategy to increase susceptibility of C. difficile spores to radiation or other stressors. PRINCIPAL FINDINGS: Here, we demonstrated that exposure of dormant C. difficile spores to a germination solution containing amino acids, minerals, and taurocholic acid resulted in initiation of germination in room air. Germination of spores in room air resulted in significantly enhanced killing by ultraviolet-C (UV-C radiation and heat. On surfaces in hospital rooms, application of germination solution resulted in enhanced eradication of spores by UV-C administered by an automated room decontamination device. Initiation of germination under anaerobic, but not aerobic, conditions resulted in increased susceptibility to killing by ethanol, suggesting that exposure to oxygen might prevent spores from progressing fully to outgrowth. Stimulation of germination also resulted in reduced survival of spores on surfaces in room air, possibly due to increased susceptibility to stressors such as oxygen and desiccation. CONCLUSIONS: Taken together, these data demonstrate that stimulation of germination could represent a novel method to enhance killing of spores by UV-C, and suggest the possible application of this strategy as a means to enhance killing by other agents.

  17. Regulation of Clostridium difficile spore germination by the CspA pseudoprotease domain.

    Science.gov (United States)

    Kevorkian, Yuzo; Shirley, David J; Shen, Aimee

    2016-03-01

    Clostridium difficile is a spore-forming obligate anaerobe that is a leading cause of healthcare-associated infections. C. difficile infections begin when its metabolically dormant spores germinate in the gut of susceptible individuals. Binding of bile salt germinants to the Csp family pseudoprotease CspC triggers a proteolytic signaling cascade consisting of the Csp family protease CspB and the cortex hydrolase SleC. Conserved across many of the Clostridia, Csp proteases are subtilisin-like serine proteases that activate pro-SleC by cleaving off its inhibitory pro-peptide. Active SleC degrades the protective cortex layer, allowing spores to resume metabolism and growth. This signaling pathway, however, is differentially regulated in C. difficile, since CspC functions both as a germinant receptor and regulator of CspB activity. CspB is also produced as a fusion to a catalytically inactive CspA domain that subsequently undergoes interdomain processing during spore formation. In this study, we investigated the role of the CspA pseudoprotease domain in regulating C. difficile spore germination. Mutational analyses revealed that the CspA domain controls CspC germinant receptor levels in mature spores and is required for optimal spore germination, particularly when CspA is fused to the CspB protease. During spore formation, the YabG protease separates these domains, although YabG itself is dispensable for germination. Bioinformatic analyses of Csp family members suggest that the CspC-regulated signaling pathway characterized in C. difficile is conserved in related Peptostreptococcaceae family members but not in the Clostridiaceae or Lachnospiraceae. Our results indicate that pseudoproteases play critical roles in regulating C. difficile spore germination and highlight that diverse mechanisms control spore germination in the Clostridia.

  18. Characterization of fungal spores in ambient particulate matter: A study from the Himalayan region

    Science.gov (United States)

    Kumar, Ajay; Attri, Arun K.

    2016-10-01

    Fungal spores as a constituent of ambient particulate matter (PM) is of concern; they not only display the physical traits of a particle, but are also potential allergens and health risk. An investigation over fourteen month was undertaken at a rural site located in the Western Himalayan region, to evaluate the PM associated fungal spores' concentration and diversity. The season-wise change in the fungal spores concentration in the Coarse Particulate Matter (CPM) fraction (aerodynamic diameter > 10 μm) varied from 500 to 3899 spores m-3. Their average concentration over 14 months was 1517 spores m-3. Significant diversity of fungal spores in the CPM samples was observed; 27 individual genera of fungal spores were identified, of which many were known allergens. Presence of Ascomycota and Basidiomycota fungal spores was dominant in the samples; ∼20% of the spores were un-characterized. The season-wise variability in fungal spores showed a statistically significant high correlation with CPM load. Maximum number concentration of the spores in CPM was recorded in the summer, while minimum in the winter. The high diversity of spores occurred during monsoon and post monsoon months. The meteorological factors played an important role in the fungal spores' distribution profile. The temporal profile of the spores showed significant correlation with the ambient temperature (T), relative humidity (RH), wind speed (WS) and planetary boundary layer (PBL) height. Strong correlation of WS with fungal spores and CPM, and wind back trajectories suggest that re-suspension and wind assisted transport of PM contributes to ambient CPM associated fungal spores.

  19. The effects of triclosan on spore germination and hyphal growth of the arbuscular mycorrhizal fungus Glomus intraradices.

    Science.gov (United States)

    Twanabasu, Bishnu R; Stevens, Kevin J; Venables, Barney J

    2013-06-01

    The effect of triclosan (5-chloro-2-[2,4-dichlorophenoxy]phenol; TCS), on spore germination, hyphal growth, and hyphal branching of the arbuscular mycorrhizal (AM) fungus, Glomus intraradices spores was evaluated at exposure concentrations of 0.4 and 4.0 μg/L in a static renewal exposure system. To determine if potential effects were mycotoxic or a consequence of impaired signaling between a host plant and the fungal symbiont, spores were incubated with and without the addition of a root exudate. Exposed spores were harvested at days 7, 14, and 21. AM spore germination, hyphal growth, and hyphal branching were significantly lower in both TCS concentrations compared to controls in non-root exudate treatments suggesting direct mycotoxic effects of TCS on AM development. Greater hyphal growth and hyphal branching in controls and 0.4μg/L TCS treatments with root exudate compared to non-root exudate treatments demonstrated growth stimulation by signaling chemicals present in the root exudate. This stimulatory effect was absent in the 4.0 μg/L TCS treatments indicating a direct effect on plant signaling compounds or plant signal response.

  20. The decision to germinate is regulated by divergent molecular networks in spores and seeds

    DEFF Research Database (Denmark)

    Vesty, Eleanor F.; Saidi, Younousse; Moody, Laura A.

    2016-01-01

    in the model bryophyte Physcomitrella patens (Aphanoregma patens). Our data suggest that the environmental signals regulating germination are conserved, but also that downstream hormone integration pathways mediating these responses in seeds were acquired after the evolution of the bryophyte lineage. Moreover......Dispersal is a key step in land plant life cycles, usually via formation of spores or seeds. Regulation of spore- or seed-germination allows control over the timing of transition from one generation to the next, enabling plant dispersal. A combination of environmental and genetic factors determines...... when seed germination occurs. Endogenous hormones mediate this decision in response to the environment. Less is known about how spore germination is controlled in earlier-evolving nonseed plants. Here, we present an in-depth analysis of the environmental and hormonal regulation of spore germination...

  1. The decision to germinate is regulated by divergent molecular networks in spores and seeds

    DEFF Research Database (Denmark)

    Vesty, Eleanor F.; Saidi, Younousse; Moody, Laura A.

    2016-01-01

    Dispersal is a key step in land plant life cycles, usually via formation of spores or seeds. Regulation of spore- or seed-germination allows control over the timing of transition from one generation to the next, enabling plant dispersal. A combination of environmental and genetic factors determines...... when seed germination occurs. Endogenous hormones mediate this decision in response to the environment. Less is known about how spore germination is controlled in earlier-evolving nonseed plants. Here, we present an in-depth analysis of the environmental and hormonal regulation of spore germination...... in the model bryophyte Physcomitrella patens (Aphanoregma patens). Our data suggest that the environmental signals regulating germination are conserved, but also that downstream hormone integration pathways mediating these responses in seeds were acquired after the evolution of the bryophyte lineage. Moreover...

  2. Metabolism of bile salts in mice influences spore germination in Clostridium difficile.

    Directory of Open Access Journals (Sweden)

    Jennifer L Giel

    Full Text Available Clostridium difficile, a spore-forming bacterium, causes antibiotic-associated diarrhea. In order to produce toxins and cause disease, C. difficile spores must germinate and grow out as vegetative cells in the host. Although a few compounds capable of germinating C. difficile spores in vitro have been identified, the in vivo signal(s to which the spores respond were not previously known. Examination of intestinal and cecal extracts from untreated and antibiotic-treated mice revealed that extracts from the antibiotic-treated mice can stimulate colony formation from spores to greater levels. Treatment of these extracts with cholestyramine, a bile salt binding resin, severely decreased the ability of the extracts to stimulate colony formation from spores. This result, along with the facts that the germination factor is small, heat-stable, and water-soluble, support the idea that bile salts stimulate germination of C. difficile spores in vivo. All extracts able to stimulate high level of colony formation from spores had a higher proportion of primary to secondary bile salts than extracts that could not. In addition, cecal flora from antibiotic-treated mice was less able to modify the germinant taurocholate relative to flora from untreated mice, indicating that the population of bile salt modifying bacteria differed between the two groups. Taken together, these data suggest that an in vivo-produced compound, likely bile salts, stimulates colony formation from C. difficile spores and that levels of this compound are influenced by the commensal gastrointestinal flora.

  3. 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.

  4. Role of YpeB in Cortex Hydrolysis during Germination of Bacillus anthracis Spores

    Science.gov (United States)

    Bernhards, Casey B.

    2014-01-01

    The infectious agent of the disease anthrax is the spore of Bacillus anthracis. Bacterial spores are extremely resistant to environmental stresses, which greatly hinders spore decontamination efforts. The spore cortex, a thick layer of modified peptidoglycan, contributes to spore dormancy and resistance by maintaining the low water content of the spore core. The cortex is degraded by germination-specific lytic enzymes (GSLEs) during spore germination, rendering the cells vulnerable to common disinfection techniques. This study investigates the relationship between SleB, a GSLE in B. anthracis, and YpeB, a protein necessary for SleB stability and function. The results indicate that ΔsleB and ΔypeB spores exhibit similar germination phenotypes and that the two proteins have a strict codependency for their incorporation into the dormant spore. In the absence of its partner protein, SleB or YpeB is proteolytically degraded soon after expression during sporulation, rather than escaping the developing spore. The three PepSY domains of YpeB were examined for their roles in the interaction with SleB. YpeB truncation mutants illustrate the necessity of a region beyond the first PepSY domain for SleB stability. Furthermore, site-directed mutagenesis of highly conserved residues within the PepSY domains resulted in germination defects corresponding to reduced levels of both SleB and YpeB in the mutant spores. These results identify residues involved in the stability of both proteins and reiterate their codependent relationship. It is hoped that the study of GSLEs and interacting proteins will lead to the use of GSLEs as targets for efficient activation of spore germination and facilitation of spore cleanup. PMID:25022853

  5. Role of YpeB in cortex hydrolysis during germination of Bacillus anthracis spores.

    Science.gov (United States)

    Bernhards, Casey B; Popham, David L

    2014-10-01

    The infectious agent of the disease anthrax is the spore of Bacillus anthracis. Bacterial spores are extremely resistant to environmental stresses, which greatly hinders spore decontamination efforts. The spore cortex, a thick layer of modified peptidoglycan, contributes to spore dormancy and resistance by maintaining the low water content of the spore core. The cortex is degraded by germination-specific lytic enzymes (GSLEs) during spore germination, rendering the cells vulnerable to common disinfection techniques. This study investigates the relationship between SleB, a GSLE in B. anthracis, and YpeB, a protein necessary for SleB stability and function. The results indicate that ΔsleB and ΔypeB spores exhibit similar germination phenotypes and that the two proteins have a strict codependency for their incorporation into the dormant spore. In the absence of its partner protein, SleB or YpeB is proteolytically degraded soon after expression during sporulation, rather than escaping the developing spore. The three PepSY domains of YpeB were examined for their roles in the interaction with SleB. YpeB truncation mutants illustrate the necessity of a region beyond the first PepSY domain for SleB stability. Furthermore, site-directed mutagenesis of highly conserved residues within the PepSY domains resulted in germination defects corresponding to reduced levels of both SleB and YpeB in the mutant spores. These results identify residues involved in the stability of both proteins and reiterate their codependent relationship. It is hoped that the study of GSLEs and interacting proteins will lead to the use of GSLEs as targets for efficient activation of spore germination and facilitation of spore cleanup.

  6. Ultraweak luminescence from germinating resting spores of Entomophthora virulenta Hall et Dunn

    Directory of Open Access Journals (Sweden)

    Janusz Sławiński

    2014-08-01

    Full Text Available Germinating resting spores of Entomophthora virulenta Hall et Dunn emit ultraweak luminescence with the intensity of the order 100 photons • s-1 • cm-2 in the spectral region 200-750 nm. The emission kinetics and intensity depend on vitality and incubation temperature of the spores. The higher the ability of resting spores to germinate, the more intense the luminescence. Elevation of the incubation temperature to 50°C enhances ultraweak luminescence. The activation energy was found to be about 15 kJ • mol-1 and 5 kJ • mol-1 for nongerminating and germinating in 50% spores, respectively. The possibility of applying ultraweak luminescence as a simple assay for the spores vitality is discussed.

  7. Temporaly germinating rhythms of moss Funaria hygrometrica Hedw. spores

    Science.gov (United States)

    Pundiak, O.; Demkiv, O.

    The process of an organism development is regular and gradual. These characteristics of the development are especially evident in archegonial plants. It was shown that spores of moss Funar ia hygrometrica Hedw. in Knop's nutrient medium with 0,2% glucose in the dark in vertical orientation of Petry dishes, germinated polarly depending on gravity direction. At the begining, the primary rhyziod developed being usually directed downwards and then after 24 hours primary chloronema developed growing usually upwards. The amyloplasts sedimentation was shown before the rhyzoid and chloronema formation. It determines not only the time, but spatial orientation of the primary rhyzoid and chloronema (Pundjak at al., 2001). EGTA in concentration of 510- 5 M inhibited the initiation of the primary rhyzoid. The primary chloronema developed as usual in 48 h after the spores sowing. Temporary cooling caused analogical effect. Basing on these results we drew the conclusion that the primary rhyzoid and chloronema differently react on the action of EGTA and the cooling. The primary chloronema was more tolerant then the rhyzoid and maintained its usual gravisensitivy. Thus, we can think that EGTA and the cooling stop the development of primary rhyzoid, but it does not disturb physiological rhythm which underlais in the base of the function of the biological clock. The stability of biological rhythms and their indeterminism in respect of described above external and internal factors is real thanks to dissipation, which makes considerable interval of uncertainties of distributions of distances between segments of biopolymers and thus, of their fermentative activities (Pundjak,2001). Therefore the rise of biological clocks of each organism is in certain sense transcendental.

  8. Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA(2mob) Operon in Foodborne Strains of Bacillus subtilis

    NARCIS (Netherlands)

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

    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. Highlevel heat resistance and slow germination of spores of some

  9. Fluorescence-based methods for the detection of pressure-induced spore germination and inactivation

    Science.gov (United States)

    Baier, Daniel; Reineke, Kai; Doehner, Isabel; Mathys, Alexander; Knorr, Dietrich

    2011-03-01

    The application of high pressure (HP) provides an opportunity for the non-thermal preservation of high-quality foods, whereas highly resistant bacterial endospores play an important role. It is known that the germination of spores can be initiated by the application of HP. Moreover, the resistance properties of spores are highly dependent on their physiological states, which are passed through during the germination. To distinguish between different physiological states and to detect the amount of germinated spores after HP treatments, two fluorescence-based methods were applied. A flow cytometric method using a double staining with SYTO 16 as an indicator for germination and propidium iodide as an indicator for membrane damage was used to detect different physiological states of the spores. During the first step of germination, the spore-specific dipicolinic acid (DPA) is released [P. Setlow, Spore germination, Curr. Opin. Microbiol. 6 (2003), pp. 550-556]. DPA reacts with added terbium to form a distinctive fluorescent complex. After measuring the fluorescence intensity at 270 nm excitation wavelength in a fluorescence spectrophotometer, the amount of germinated spores can be determined. Spores of Bacillus subtilis were treated at pressures from 150 to 600 MPa and temperatures from 37 °C to 60 °C in 0.05 M ACES buffer solution (pH 7) for dwell times of up to 2 h. During the HP treatments, inactivation up to 2log 10 cycles and thermal sensitive populations up to 4log 10 cycles could be detected by plate counts. With an increasing number of thermal sensitive spores, an increased proportion of spores in germinated states was detected by flow cytometry. Also the released amount of DPA increased during the dwell times. Moreover, a clear pressure-temperature-time-dependency was shown by screening different conditions. The fluorescence-based measurement of the released DPA can provide the opportunity of an online monitoring of the germination of spores under HP inside

  10. 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.

  11. Glycerol enhances fungal germination at the water-activity limit for life.

    Science.gov (United States)

    Stevenson, Andrew; Hamill, Philip G; Medina, Ángel; Kminek, Gerhard; Rummel, John D; Dijksterhuis, Jan; Timson, David J; Magan, Naresh; Leong, Su-Lin L; Hallsworth, John E

    2017-03-01

    For the most-extreme fungal xerophiles, metabolic activity and cell division typically halts between 0.700 and 0.640 water activity (approximately 70.0-64.0% relative humidity). Here, we investigate whether glycerol can enhance xerophile germination under acute water-activity regimes, using an experimental system which represents the biophysical limit of Earth's biosphere. Spores from a variety of species, including Aspergillus penicillioides, Eurotium halophilicum, Xerochrysium xerophilum (formerly Chrysosporium xerophilum) and Xeromyces bisporus, were produced by cultures growing on media supplemented with glycerol (and contained up to 189 mg glycerol g dry spores(-1) ). The ability of these spores to germinate, and the kinetics of germination, were then determined on a range of media designed to recreate stresses experienced in microbial habitats or anthropogenic systems (with water-activities from 0.765 to 0.575). For A. penicillioides, Eurotium amstelodami, E. halophilicum, X. xerophilum and X. bisporus, germination occurred at lower water-activities than previously recorded (0.640, 0.685, 0.651, 0.664 and 0.637 respectively). In addition, the kinetics of germination at low water-activities were substantially faster than those reported previously. Extrapolations indicated theoretical water-activity minima below these values; as low as 0.570 for A. penicillioides and X. bisporus. Glycerol is present at high concentrations (up to molar levels) in many types of microbial habitat. We discuss the likely role of glycerol in expanding the water-activity limit for microbial cell function in relation to temporal constraints and location of the microbial cell or habitat. The findings reported here have also critical implications for understanding the extremes of Earth's biosphere; for understanding the potency of disease-causing microorganisms; and in biotechnologies that operate at the limits of microbial function. © 2016 The Authors. Environmental Microbiology

  12. The decision to germinate is regulated by divergent molecular networks in spores and seeds

    DEFF Research Database (Denmark)

    Vesty, Eleanor F.; Saidi, Younousse; Moody, Laura A.;

    2016-01-01

    , the role of abscisic acid and diterpenes (gibberellins) in germination assumed much greater importance as land plant evolution progressed. We conclude that the endogenous hormone signalling networks mediating germination in response to the environment may have evolved independently in spores and seeds...

  13. Studies on the physiology of Funaria hygrometrica spore germination. Part IV. The effect of blue and red light on the germination of spores

    Directory of Open Access Journals (Sweden)

    J. Krupa

    2015-05-01

    Full Text Available The effect of radiation with wave-lengths 654 nm and 425 nm on the germination of Funaria hydgrometrica spores has been studied. The wave-length bands used for the radiation treatment were employed for various durations and in various combinations. The effects of red and blue light were different in the individual phases of germination when after an inductive radiation treatment light in the 425 nm wave-length was supplied. Differences in the effect of red and blue light are observable in the "post-effects" land in the germination morphology.

  14. 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

  15. Effect of linear alkyl benzene sulfonate on germination of spores of the aquatic fern Ceratopteris thalictroides

    Energy Technology Data Exchange (ETDEWEB)

    Singh, J.; Devi, S. (National Botanical Research Institute, Lucknow (India))

    1989-07-01

    Validity of fern spore germination bioassays for the effects of environmental pollution was established by many researchers. Some workers studied the phytotoxicity of linear alkyl benzene sulfonate (LAS) on the spores of Diplazium esculentum and observed that LAS levels above 0.001% are toxic to fern spores. Water pollution due to synthetic detergents has been increasing continuously during the last few years due to their extensive use in domestic life, agriculture and industry. These detergents are among the most common pollutants responsible for water pollution. In view of this fact, the phytotoxicity of LAS on germination of an aquatic fern Ceratopteris thalictroides spores was studied. However, in these studies, only germination pattern was taken as index and no observations were made on the developmental stages.

  16. 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.

  17. Effects of nifedipine on gravi-dependent germination of moss spores

    Science.gov (United States)

    Khorkavtsiv, O. Y.; Demkiv, O. T.

    Influence of gravity on germination of spores and dependence of the generation of a polar axis on a Ca2+ influx were investigated. The germination of spores does not depend on gravity but outgrowth polarity is controlled by light and gravity (Sytnik et al., 1989; Pundiak et al., 2001). We have shown that gravity determines the polarity of germination of spores and development of rhizoid and chloronemal outgrowths in both moss species -- Ceratodon purpureus and Pohlia nutans, the alignment of polar of germinating spores in C. purpureus, however, is less dependent on gravistimulus than in P. nutans. In 48 h after sowing onto culture medium+0,2% glucose in vertically oriented petri dishes in darkness spores of P. nutans germinated positively gravitropic rhizoid at the lower spore side and negatively gravitropic chloronema at the opposite one. The germination of C. purpureus spores is similar but the outgrowths show the lower level of alignment to the gravity vector than that of P. nutans, the dispersion of angles being 8,9 vs. 1,2 respectively. The cellular mechanism by which gravity acts remains unknown. The intracellular signaling Ca2+ ions play a crucial role in gravity perception and ability of a single cell to respond to gravity. We determined relative intensity of Ca2+ luminescence in the spores before their germination and at the early stages of outgrowth formation after treatment with the nifedipine and in a dependence on gravity vector. Gravity determined the position of outgrowth initiation zone and later on the growth direction of spore filaments. Treatment with nifedipine suppressed the gravity-directed calcium channel influx and distrupted polar growth of outgrowths. In experiments with calcium channel blocker sterilized spores were pregerminated on normal Knop's agar one day after were transferred to 50 μ M nifedipine just before emergence of the germ tube. After 48 h on nifedipine treatment, 50% spores did not germinate, 35% grew apolarily and in 15

  18. The Use of Germinants to Potentiate the Sensitivity of Bacillus anthracis Spores to Peracetic Acid.

    Science.gov (United States)

    Celebi, Ozgur; Buyuk, Fatih; Pottage, Tom; Crook, Ant; Hawkey, Suzanna; Cooper, Callum; Bennett, Allan; Sahin, Mitat; Baillie, Leslie

    2016-01-01

    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 10(4) spores/g. Treatment with germinants followed 1 h 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.

  19. The use of germinants to potentiate the sensitivity of Bacillus anthracis spores to peracetic acid

    Directory of Open Access Journals (Sweden)

    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.

  20. Meteorological factors associated with abundance of airborne fungal spores over natural vegetation

    Science.gov (United States)

    Crandall, Sharifa G.; Gilbert, Gregory S.

    2017-08-01

    The abundance of airborne fungal spores in agricultural and urban settings increases with greater air temperature, relative humidity, or precipitation. The same meteorological factors that affect temporal patterns in spore abundance in managed environments also vary spatially across natural habitats in association with differences in vegetation structure. Here we investigated how temporal and spatial variation in aerial spore abundance is affected by abiotic (weather) and biotic (vegetation) factors as a foundation for predicting how fungi may respond to changes in weather and land-use patterns. We measured the phenology of airborne fungal spores across a mosaic of naturally occurring vegetation types at different time scales to describe (1) how spore abundance changes over time, (2) which local meteorological variables are good predictors for airborne spore density, and (3) whether spore abundance differs across vegetation types. Using an air volumetric vacuum sampler, we collected spore samples at 3-h intervals over a 120-h period in a mixed-evergreen forest and coastal prairie to measure diurnal, nocturnal, and total airborne spore abundance across vegetation types. Spore samples were also collected at weekly and monthly intervals in mixed-evergreen forest, redwood forest, and maritime chaparral vegetation types from 12 field sites across two years. We found greater airborne spore densities during the wetter winter months compared to the drier summer months. Mean total spore abundance in the mixed-evergreen forest was twice than in the coastal prairie, but there were no significant differences in total airborne spore abundance among mixed-evergreen forest, redwood forest, and maritime chaparral vegetation types. Weekly and monthly peaks in airborne spore abundance corresponded with rain events and peaks in soil moisture. Overall, temporal patterns in meteorological factors were much more important in determining airborne fungal spore abundance than the

  1. Glycerol enhances fungal germination at the water‐activity limit for life

    Science.gov (United States)

    Stevenson, Andrew; Hamill, Philip G.; Medina, Ángel; Kminek, Gerhard; Rummel, John D.; Dijksterhuis, Jan; Timson, David J.; Magan, Naresh; Leong, Su‐Lin L.

    2016-01-01

    Summary For the most‐extreme fungal xerophiles, metabolic activity and cell division typically halts between 0.700 and 0.640 water activity (approximately 70.0–64.0% relative humidity). Here, we investigate whether glycerol can enhance xerophile germination under acute water‐activity regimes, using an experimental system which represents the biophysical limit of Earth's biosphere. Spores from a variety of species, including Aspergillus penicillioides, Eurotium halophilicum, Xerochrysium xerophilum (formerly Chrysosporium xerophilum) and Xeromyces bisporus, were produced by cultures growing on media supplemented with glycerol (and contained up to 189 mg glycerol g dry spores−1). The ability of these spores to germinate, and the kinetics of germination, were then determined on a range of media designed to recreate stresses experienced in microbial habitats or anthropogenic systems (with water‐activities from 0.765 to 0.575). For A. penicillioides, Eurotium amstelodami, E. halophilicum, X. xerophilum and X. bisporus, germination occurred at lower water‐activities than previously recorded (0.640, 0.685, 0.651, 0.664 and 0.637 respectively). In addition, the kinetics of germination at low water‐activities were substantially faster than those reported previously. Extrapolations indicated theoretical water‐activity minima below these values; as low as 0.570 for A. penicillioides and X. bisporus. Glycerol is present at high concentrations (up to molar levels) in many types of microbial habitat. We discuss the likely role of glycerol in expanding the water‐activity limit for microbial cell function in relation to temporal constraints and location of the microbial cell or habitat. The findings reported here have also critical implications for understanding the extremes of Earth's biosphere; for understanding the potency of disease‐causing microorganisms; and in biotechnologies that operate at the limits of microbial function. PMID:27631633

  2. Evaluation of germination, distribution, and persistence of Bacillus subtilis spores through the gastrointestinal tract of chickens.

    Science.gov (United States)

    Latorre, J D; Hernandez-Velasco, X; Kallapura, G; Menconi, A; Pumford, N R; Morgan, M J; Layton, S L; Bielke, L R; Hargis, B M; Téllez, G

    2014-07-01

    Spores are popular as direct-fed microbials, though little is known about their mode of action. Hence, the first objective of the present study was to evaluate the in vitro germination and growth rate of Bacillus subtilis spores. Approximately 90% of B. subtilis spores germinate within 60 min in the presence of feed in vitro. The second objective was to determine the distribution of these spores throughout different anatomical segments of the gastrointestinal tract (GIT) in a chicken model. For in vivo evaluation of persistence and dissemination, spores were administered to day-of-hatch broiler chicks either as a single gavage dose or constantly in the feed. During 2 independent experiments, chicks were housed in isolation chambers and fed sterile corn-soy-based diets. In these experiments one group of chickens was supplemented with 10(6) spores/g of feed, whereas a second group was gavaged with a single dose of 10(6) spores per chick on day of hatch. In both experiments, crop, ileum, and cecae were sampled from 5 chicks at 24, 48, 72, 96, and 120 h. Viable B. subtilis spores were determined by plate count method after heat treatment (75°C for 10 min). The number of recovered spores was constant through 120 h in each of the enteric regions from chickens receiving spores supplemented in the feed. However, the number of recovered B. subtilis spores was consistently about 10(5) spores per gram of digesta, which is about a 1-log10 reduction of the feed inclusion rate, suggesting approximately a 90% germination rate in the GIT when fed. On the other hand, recovered B. subtilis spores from chicks that received a single gavage dose decreased with time, with only approximately 10(2) spores per gram of sample by 120 h. This confirms that B. subtilis spores are transiently present in the GIT of chickens, but the persistence of vegetative cells is presently unknown. For persistent benefit, continuous administration of effective B. subtilis direct-fed microbials as vegetative

  3. Kinetics of germination of individual spores of Geobacillus stearothermophilus as measured by raman spectroscopy and differential interference contrast microscopy.

    Directory of Open Access Journals (Sweden)

    Tingting Zhou

    Full Text Available Geobacillus stearothermophilus is a gram-positive, thermophilic bacterium, spores of which are very heat resistant. Raman spectroscopy and differential interference contrast microscopy were used to monitor the kinetics of germination of individual spores of G. stearothermophilus at different temperatures, and major conclusions from this work were as follows. 1 The CaDPA level of individual G. stearothermophilus spores was similar to that of Bacillus spores. However, the Raman spectra of protein amide bands suggested there are differences in protein structure in spores of G. stearothermophilus and Bacillus species. 2 During nutrient germination of G. stearothermophilus spores, CaDPA was released beginning after a lag time (T(lag between addition of nutrient germinants and initiation of CaDPA release. CaDPA release was complete at T(release, and DT(release (T(release - T(lag was 1-2 min. 3 Activation by heat or sodium nitrite was essential for efficient nutrient germination of G. stearothermophilus spores, primarily by decreasing T(lag values. 4 Values of T(lag and T(release were heterogeneous among individual spores, but DT(release values were relatively constant. 5 Temperature had major effects on nutrient germination of G. stearothermophilus spores, as at temperatures below 65°C, average T(lag values increased significantly. 6 G. stearothermophilus spore germination with exogenous CaDPA or dodecylamine was fastest at 65°C, with longer T(lag values at lower temperatures. 7 Decoating of G. stearothermophilus spores slowed nutrient germination slightly and CaDPA germination significantly, but increased dodecylamine germination markedly. These results indicate that the dynamics and heterogeneity of the germination of individual G. stearothermophilus spores are generally similar to that of Bacillus species.

  4. Observation of the dynamic germination of single bacterial spores using rapid Raman imaging

    Science.gov (United States)

    Kong, Lingbo; Setlow, Peter; Li, Yong-qing

    2014-01-01

    The dynamics of bacterial spore germination were successfully observed using a fast Raman imaging system, in combination with real-time phase contrast microscopy. By using a multifocus scan scheme, the spontaneous Raman-scattering imaging acquisition speed was increased to ˜30 s per frame while maintaining diffraction-limited resolution, which allowed monitoring of the dynamics of spore germination on a time scale of tens of seconds to a few minutes. This allowed simultaneous gathering of rich spatial distribution information on different cellular components including time-lapse molecular images of Ca-dipicolinic acid, protein, and nucleic acid during germination of single bacterial spores for the periods of 30 to 60 min.

  5. A novel method for standardized application of fungal spore coatings for mosquito exposure bioassays

    NARCIS (Netherlands)

    Farenhorst, M.; Knols, B.G.J.

    2010-01-01

    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

  6. Effect of essential oils on Aspergillus spore germination, growth and mycotoxin production: a potential source of botanical food preservative

    OpenAIRE

    Negero Gemeda; Yimtubezinash Woldeamanuel; Daniel Asrat; Asfaw Debella

    2014-01-01

    Objective: To investigate effect of essential oils on Aspergillus spore germination, growth and mycotoxin production. Method: 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. Results: Cymbopogon martinii, Foeniculum vulgare and Trachyspermum ammi (T. ammi) essential oils were tested against toxicogeni...

  7. 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

  8. 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.

  9. Germination of Dictyotelium discoideum spores. A sup 31 P NMR analysis

    Energy Technology Data Exchange (ETDEWEB)

    Klein, G.; Martin, J.B.; Bof, M.; Satre, M. (Centre d' Etudes Nucleaires, Grenoble (France)); Cotter, D.A. (Univ. of Windsor, Ontario (Canada))

    1988-10-18

    Perchloric acid extracts of Dictyostelium spores have been investigated by {sup 31}P nuclear magnetic resonance (NMR) spectroscopy. This analysis has allowed the assignment of all the {sup 31}P resonances observed in vivo to specific compounds. Dormant spores have been found to contain as prominent phosphorylated metabolites two phosphomonoesters, phosphoethanolamine and inositol hexakis(phosphate), two phosphodiesters, glycerophosphocholine and glycerophosphoethanolamine, as well as nucleoside triphosphates and polyphosphates. The very large amounts of glycerophosphocholine, glycerophosphoethanolamine, and phosphoethanolamine in spores were the most remarkable differences from Dictyostelium amoebae. In vivo {sup 31}P NMR has shown that the peak of nucleoside triphosphates in dormant spores was maintained metabolically since it disappeared completely upon anaerobiosis. The pH-sensitive {sup 31}P NMR signal of phosphoethanolamine was used to determine internal pH, and a value of pH 6.5 was found in aerobic Dictyostelium dormant spores. Spore germination, induced by activation with heat shock treatment, was monitored noninvasively by {sup 31}P NMR. No change in phosphorylated components was observed to have occurred during the activation step. The major modifications in phosphorylated metabolites observed upon germination of the activated spores were the progressive disappearance of the two phosphodiesters glycerophosphocholine and glycerophosphoethanolamine.

  10. Changes in Bacillus Spore Small Molecules, rRNA, Germination, and Outgrowth after Extended Sublethal Exposure to Various Temperatures: Evidence that Protein Synthesis Is Not Essential for Spore Germination.

    Science.gov (United States)

    Korza, George; Setlow, Barbara; Rao, Lei; Li, Qiao; Setlow, Peter

    2016-12-15

    rRNAs of dormant spores of Bacillus subtilis were >95% degraded during extended incubation at 50°C, as reported previously (E. Segev, Y. Smith, and S. Ben-Yehuda, Cell 148:139-114, 2012, doi:http://dx.doi.org/10.1016/j.cell.2011.11.059), and this was also true of spores of Bacillus megaterium Incubation of spores of these two species for ∼20 h at 75 to 80°C also resulted in the degradation of all or the great majority of the 23S and 16S rRNAs, although this rRNA degradation was slower than nonenzymatic hydrolysis of purified rRNAs at these temperatures. This rRNA degradation at high temperature generated almost exclusively oligonucleotides with minimal levels of mononucleotides. RNase Y, suggested to be involved in rRNA hydrolysis during B. subtilis spore incubation at 50°C, did not play a role in B. subtilis spore rRNA breakdown at 80°C. Twenty hours of incubation of Bacillus spores at 70°C also decreased the already minimal levels of ATP in dormant spores 10- to 30-fold, to ≤0.01% of the total free adenine nucleotide levels. Spores depleted of rRNA were viable and germinated relatively normally, often even faster than starting spores. Their return to vegetative growth was also similar to that of untreated spores for B. megaterium spores and slower for heat-treated B. subtilis spores; accumulation of rRNA took place only after completion of spore germination. These findings thus strongly suggest that protein synthesis is not essential for Bacillus spore germination.IMPORTANCE A recent report (L. Sinai, A. Rosenberg, Y. Smith, E. Segev, and S. Ben-Yehuda, Mol Cell 57:3486-3495, 2015, doi:http://dx.doi.org/10.1016/j.molcel.2014.12.019) suggested that protein synthesis is essential for early steps in the germination of dormant spores of Bacillus subtilis If true, this would be a paradigm shift in our understanding of spore germination. We now show that essentially all of the rRNA can be eliminated from spores of Bacillus megaterium or B. subtilis, and these

  11. Airspora concentrations in the Vaal-triangle-monitoring and potential health-effects.2, fungal spores

    CSIR Research Space (South Africa)

    Vismer, HF

    1995-08-01

    Full Text Available Atmospheric fungal spores were monitored in Vanderbijlpark for the period 1991-92 as part of the Vaal triangle air pollution health study of the medical research council and the CSIR. Cladosporium, Aspergillus/ Penicillium, Alternaria and Epicoccum...

  12. 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.

  13. Arabitol and mannitol as tracers for the quantification of airborne fungal spores

    Science.gov (United States)

    Bauer, Heidi; Claeys, Magda; Vermeylen, Reinhilde; Schueller, Elisabeth; Weinke, Gert; Berger, Anna; Puxbaum, Hans

    Fungal spores constitute a sizeable fraction of coarse organic carbon (OC) in the atmospheric aerosol. In order to avoid tedious spore count methods, tracers for quantifying the spore-OC in atmospheric aerosol are sought. Arabitol and mannitol have been proposed as such tracers, since no other emission sources for these compounds have been reported. By parallel investigations of spore counts and tracer determinations from PM 10 filter samples we could derive quantitative relationships between the amounts of tracer compounds and the numbers of spores in the atmosphere for different sites in the area of Vienna. We obtained over all average relationships of 1.2 pg arabitol spore -1, with a range of 0.8-1.8, and 1.7 pg mannitol spore -1, with a range of 1.2-2.4, with a clear site dependence. Thus, using these conversion factors from spore counts to spore-OC and spore-mass, along with analytical data for arabitol or mannitol in filter samples, the contribution of fungal spores to the OC and to the mass balance of atmospheric aerosol particles can be estimated.

  14. The Role of Aquaporins in pH-Dependent Germination of Rhizopus delemar Spores.

    Science.gov (United States)

    Turgeman, Tidhar; Shatil-Cohen, Arava; Moshelion, Menachem; Teper-Bamnolker, Paula; Skory, Christopher D; Lichter, Amnon; Eshel, Dani

    2016-01-01

    Rhizopus delemar and associated species attack a wide range of fruit and vegetables after harvest. Host nutrients and acidic pH are required for optimal germination of R. delemar, and we studied how this process is triggered. Glucose induced spore swelling in an acidic environment, expressed by an up to 3-fold increase in spore diameter, whereas spore diameter was smaller in a neutral environment. When suspended in an acidic environment, the spores started to float, indicating a change in their density. Treatment of the spores with HgCl2, an aquaporin blocker, prevented floating and inhibited spore swelling and germ-tube emergence, indicating the importance of water uptake at the early stages of germination. Two putative candidate aquaporin-encoding genes-RdAQP1 and RdAQP2-were identified in the R. delemar genome. Both presented the conserved NPA motif and six-transmembrane domain topology. Expressing RdAQP1 and RdAQP2 in Arabidopsis protoplasts increased the cells' osmotic water permeability coefficient (Pf) compared to controls, indicating their role as water channels. A decrease in R. delemar aquaporin activity with increasing external pH suggested pH regulation of these proteins. Substitution of two histidine (His) residues, positioned on two loops facing the outer side of the cell, with alanine eliminated the pH sensing resulting in similar Pf values under acidic and basic conditions. Since hydration is critical for spore switching from the resting to activate state, we suggest that pH regulation of the aquaporins can regulate the initial phase of R. delemar spore germination, followed by germ-tube elongation and host-tissue infection.

  15. 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

  16. Detection of Fungal Spores Using a Generic Surface Plasmon Resonance Immunoassay

    DEFF Research Database (Denmark)

    Skottrup, Peter; Hearty, Stephen; Frøkiær, Hanne;

    2007-01-01

    . Spiked Pst samples were further examined in a background of a related spore and it was found that Pst quantification was possible in this mixture. This study represent the first use of SPR technology for fungal spore detection as well as the first report of a successful biosensor-based detection strategy...

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

    Science.gov (United States)

    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 were trapped using modified Tauber-like pollen trap, and the recipient solutions were subjected to acetolysis. Results revealed the abundance of fungal spores, pollen, fern spores, algal cysts and diatoms in decreasing order of dominance. The atmosphere was qualitatively and quantitatively dominated by pollen during the period of late rainy/harmattan season than the rainy season. Numerous fungal spores were trapped throughout the sampling periods among which Alternaria spp., Fusarium spp., Cladosporium spp. and Curvularia spp. dominated. These fungi have been implicated in allergic diseases and are dermatophytic, causing diverse skin diseases. Other pathogenic fungi found in the studied aeroflora were Dreschlera spp., Helminthosporium spp., Torula spp., Pithomyces spp., Tetraploa spp., Nigrospora ssp., Spadicoides spp., Puccinia spp. and Erysiphe graminis. Total pollen and fungal spores counts do not show significant correlation with meteorological parameters.

  18. Summoning the wind: Hydrodynamic cooperation of forcibly ejected fungal spores

    CERN Document Server

    Roper, Marcus; Cobb, Ann; Dillard, Helene R; Pringle, Anne

    2009-01-01

    The forcibly launched spores of the crop pathogen \\emph{Sclerotinia sclerotiorum} must eject through many centimeters of nearly still air to reach the flowers of the plants that the fungus infects. Because of their microscopic size, individually ejected spores are quickly brought to rest by drag. In the accompanying fluid dynamics video we show experimental and numerical simulations that demonstrate how, by coordinating the nearly simultaneous ejection of hundreds of thousands of spores,\\emph{Sclerotinia} and other species of apothecial fungus are able to sculpt a flow of air that carries spores across the boundary layer and around intervening obstacles. Many spores are sacrificed to create this flow of air. Although high speed imaging of spore launch in a wild isolate of the dung fungus \\emph{Ascobolus} shows that the synchronization of spore ejections is self-organized, which could lead to spores delaying their ejection to avoid being sacrificed, simulations and asymptotic analysis show that, close the frui...

  19. In situ investigation of Geobacillus stearothermophilus spore germination and inactivation mechanisms under moderate high pressure.

    Science.gov (United States)

    Georget, Erika; Kapoor, Shobhna; Winter, Roland; Reineke, Kai; Song, Youye; Callanan, Michael; Ananta, Edwin; Heinz, Volker; Mathys, Alexander

    2014-08-01

    Bacterial spores are a major concern for food safety due to their high resistance to conventional preservation hurdles. Innovative hurdles can trigger bacterial spore germination or inactivate them. In this work, Geobacillus stearothermophilus spore high pressure (HP) germination and inactivation mechanisms were investigated by in situ infrared spectroscopy (FT-IR) and fluorometry. G. stearothermophilus spores' inner membrane (IM) was stained with Laurdan fluorescent dye. Time-dependent FT-IR and fluorescence spectra were recorded in situ under pressure at different temperatures. The Laurdan spectrum is affected by the lipid packing and level of hydration, and provided information on the IM state through the Laurdan generalized polarization. Changes in the -CH2 and -CH3 asymmetric stretching bands, characteristic of lipids, and in the amide I' band region, characteristic of proteins' secondary structure elements, enabled evaluation of the impact of HP on endospores lipid and protein structures. These studies were complemented by ex situ analyses (plate counts and microscopy). The methods applied showed high potential to identify germination mechanisms, particularly associated to the IM. Germination up to 3 log10 was achieved at 200 MPa and 55 °C. A molecular-level understanding of these mechanisms is important for the development and validation of multi-hurdle approaches to achieve commercial sterility.

  20. Quantitative Proteomic Analysis of Germination of Nosema bombycis Spores under Extremely Alkaline Conditions

    Science.gov (United States)

    Liu, Han; Chen, Bosheng; Hu, Sirui; Liang, Xili; Lu, Xingmeng; Shao, Yongqi

    2016-01-01

    The microsporidian Nosema bombycis is an obligate intracellular pathogen of the silkworm Bombyx mori, causing the epidemic disease Pebrine and extensive economic losses in sericulture. Although N. bombycis forms spores with rigid spore walls that protect against various environmental pressures, ingested spores germinate immediately under the extremely alkaline host gut condition (Lepidoptera gut pH > 10.5), which is a key developmental turning point from dormant state to infected state. However, to date this process remains poorly understood due to the complexity of the animal digestive tract and the lack of genetic tools for microsporidia. Here we show, using an in vitro spore germination model, how the proteome of N. bombycis changes during germination, analyse specific metabolic pathways employed in detail, and validate key functional proteins in vivo in silkworms. By a label-free quantitative proteomics approach that is directly based on high-resolution mass spectrometry (MS) data, a total of 1136 proteins were identified with high confidence, with 127 proteins being significantly changed in comparison to non-germinated spores. Among them, structural proteins including polar tube protein 1 and 3 and spore wall protein (SWP) 4 and 30 were found to be significantly down-regulated, but SWP9 significantly up-regulated. Some nucleases like polynucleotide kinase/phosphatase and flap endonucleases 1, together with a panel of hydrolases involved in protein degradation and RNA cleavage were overrepresented too upon germination, which implied that they might play important roles during spore germination. The differentially regulated trends of these genes were validated, respectively, by quantitative RT-PCR and 3 proteins of interest were confirmed by Western blotting analyses in vitro and in vivo. Furthermore, the pathway analysis showed that abundant up- and down-regulations appear involved in the glycolysis, pentose phosphate pathway, purine, and pyrimidine metabolism

  1. Quantitative Proteomic Analysis of Germination of Nosema bombycis Spores under Extremely Alkaline Conditions.

    Science.gov (United States)

    Liu, Han; Chen, Bosheng; Hu, Sirui; Liang, Xili; Lu, Xingmeng; Shao, Yongqi

    2016-01-01

    The microsporidian Nosema bombycis is an obligate intracellular pathogen of the silkworm Bombyx mori, causing the epidemic disease Pebrine and extensive economic losses in sericulture. Although N. bombycis forms spores with rigid spore walls that protect against various environmental pressures, ingested spores germinate immediately under the extremely alkaline host gut condition (Lepidoptera gut pH > 10.5), which is a key developmental turning point from dormant state to infected state. However, to date this process remains poorly understood due to the complexity of the animal digestive tract and the lack of genetic tools for microsporidia. Here we show, using an in vitro spore germination model, how the proteome of N. bombycis changes during germination, analyse specific metabolic pathways employed in detail, and validate key functional proteins in vivo in silkworms. By a label-free quantitative proteomics approach that is directly based on high-resolution mass spectrometry (MS) data, a total of 1136 proteins were identified with high confidence, with 127 proteins being significantly changed in comparison to non-germinated spores. Among them, structural proteins including polar tube protein 1 and 3 and spore wall protein (SWP) 4 and 30 were found to be significantly down-regulated, but SWP9 significantly up-regulated. Some nucleases like polynucleotide kinase/phosphatase and flap endonucleases 1, together with a panel of hydrolases involved in protein degradation and RNA cleavage were overrepresented too upon germination, which implied that they might play important roles during spore germination. The differentially regulated trends of these genes were validated, respectively, by quantitative RT-PCR and 3 proteins of interest were confirmed by Western blotting analyses in vitro and in vivo. Furthermore, the pathway analysis showed that abundant up- and down-regulations appear involved in the glycolysis, pentose phosphate pathway, purine, and pyrimidine metabolism

  2. Fungal spores as potential ice nuclei in fog/cloud water and snow

    Science.gov (United States)

    Bauer, Heidi; Goncalves, Fabio L. T.; Schueller, Elisabeth; Puxbaum, Hans

    2010-05-01

    INTRODUCTION: In discussions about climate change and precipitation frequency biological ice nucleation has become an issue. While bacterial ice nucleation (IN) is already well characterized and even utilized in industrial processes such as the production of artificial snow or to improve freezing processes in food industry, less is known about the IN potential of fungal spores which are also ubiquitous in the atmosphere. A recent study performed at a mountain top in the Rocky Mountains suggests that fungal spores and/or pollen might play a role in increased IN abundance during periods of cloud cover (Bowers et al. 2009). In the present work concentrations of fungal spores in fog/cloud water and snow were determined. EXPERIMENTAL: Fog samples were taken with an active fog sampler in 2008 in a traffic dominated area and in a national park in São Paulo, Brazil. The number concentrations of fungal spores were determined by microscopic by direct enumeration by epifluorescence microscopy after staining with SYBR Gold nucleic acid gel stain (Bauer et al. 2008). RESULTS: In the fog water collected in the polluted area at a junction of two highly frequented highways around 22,000 fungal spores mL-1 were counted. Fog in the national park contained 35,000 spores mL-1. These results were compared with cloud water and snow samples from Mt. Rax, situated at the eastern rim of the Austrian Alps. Clouds contained on average 5,900 fungal spores mL-1 cloud water (1,300 - 11,000) or 2,200 spores m-3 (304 - 5,000). In freshly fallen snow spore concentrations were lower than in cloud water, around 1,000 fungal spores mL-1 were counted (Bauer et al. 2002). In both sets of samples representatives of the ice nucleating genus Fusarium could be observed. REFERENCES: Bauer, H., Kasper-Giebl, A., Löflund, M., Giebl, H., Hitzenberger, R., Zibuschka, F., Puxbaum, H. (2002). The contribution of bacteria and fungal spores to the organic carbon content of cloud water, precipitation and aerosols

  3. Effects of water potential on spore germination and viability of Fusarium species.

    Science.gov (United States)

    Palmero Llamas, D; de Cara Gonzalez, M; Iglesias Gonzalez, C; Ruíz Lopez, G; Tello Marquina, J C

    2008-11-01

    Germination of macroconidia and/or microconidia of 24 strains of Fusarium solani, F. chlamydosporum, F. culmorum, F. equiseti, F. verticillioides, F. sambucinum, F. oxysporum and F. proliferatum isolated from fluvial channels and sea beds of the south-eastern coast of Spain, and three control strains (F. oxysporum isolated from affected cultures) was studied in distilled water in response to a range of water potentials adjusted with NaCl. (0, -13.79, -41.79, -70.37, -99.56 and -144.54 bars). The viability (UFC/ml) of suspensions was also tested in three time periods (0, 24 and 48 h). Conidia always germinated in distilled water. The pattern of conidial germination observed of F. verticilloides, F. oxysporum, F. proliferatum, F. chlamydosporum and F. culmorum was similar. A great diminution of spore germination was found in -13.79 bars solutions. Spore germination percentage for F. solani isolates was maximal at 48 h and -13.79 bars with 21.33% spore germination, 16% higher than germination in distilled water. F. equiseti shows the maximum germination percentage in -144.54 bars solution in 24 h time with 12.36% germination. This results did not agree with those obtained in the viability test were maximum germination was found in distilled water. The viability analysis showed the great capacity of F. verticilloides strains to form viable colonies, even in such extreme conditions as -144.54 bars after 24 h F. proliferatum colony formation was prevented in the range of -70.37 bars. These results show the clear affectation of water potential to conidia germination of Fusaria. The ability of certain species of Fusarium to develop a saprophytic life in the salt water of the Mediterranean Sea could be certain. Successful germination, even under high salty media conditions, suggests that Fusarium spp. could have a competitive advantage over other soil fungi in crops irrigated with saline water. In the specific case of F. solani, water potential of -13.79 bars affected

  4. Extracellular proteases from Streptomyces phaeopurpureus ExPro138 inhibit spore adhesion, germination and appressorium formation in Colletotrichum coccodes.

    Science.gov (United States)

    Palaniyandi, S A; Yang, S H; Suh, J-W

    2013-07-01

    To study the antifungal mechanism of proteases from Streptomyces phaeopurpureus strain ExPro138 towards Colletotrichum coccodes and to evaluate its utilization as biofungicide. We screened proteolytic Streptomyces strains from the yam rhizosphere with antifungal activity. Forty proteolytic Streptomyces were isolated, among which eleven isolates showed gelatinolytic activity and antagonistic activity on C. coccodes. Of the 11 isolates, protease preparation from an isolate designated ExPro138 showed antifungal activity. 16S rDNA sequence analysis of the strain showed 99% similarity with Streptomyces phaeopurepureus (EU841588.1). Zymography analysis of the ExPro138 culture filtrate revealed that the strain produced several extracellular proteases. The protease preparation inhibited spore germination, spore adhesion to polystyrene surface and appressorium formation. Microscopic study of the interaction between ExPro138 and C. coccodes revealed that ExPro138 was mycoparasitic on C. coccodes. The protease preparation also reduced anthracnose incidence on tomato fruits compared with untreated control. This study demonstrates possibility of utilizing antifungal proteases derived from antagonistic microbes as biofungicide. Microbial proteases having the ability to inhibit spore adhesion and appressorium formation could be used to suppress infection establishment by foliar fungal pathogens at the initial stages of the infection process. Journal of Applied Microbiology © 2013 The Society for Applied Microbiology.

  5. Identification of a Novel Lipoprotein Regulator of Clostridium difficile Spore Germination.

    Directory of Open Access Journals (Sweden)

    Kelly A Fimlaid

    2015-10-01

    Full Text Available Clostridium difficile is a Gram-positive spore-forming pathogen and a leading cause of nosocomial diarrhea. C. difficile infections are transmitted when ingested spores germinate in the gastrointestinal tract and transform into vegetative cells. Germination begins when the germinant receptor CspC detects bile salts in the gut. CspC is a subtilisin-like serine pseudoprotease that activates the related CspB serine protease through an unknown mechanism. Activated CspB cleaves the pro-SleC zymogen, which allows the activated SleC cortex hydrolase to degrade the protective cortex layer. While these regulators are essential for C. difficile spores to outgrow and form toxin-secreting vegetative cells, the mechanisms controlling their function have only been partially characterized. In this study, we identify the lipoprotein GerS as a novel regulator of C. difficile spore germination using targeted mutagenesis. A gerS mutant has a severe germination defect and fails to degrade cortex even though it processes SleC at wildtype levels. Using complementation analyses, we demonstrate that GerS secretion, but not lipidation, is necessary for GerS to activate SleC. Importantly, loss of GerS attenuates the virulence of C. difficile in a hamster model of infection. Since GerS appears to be conserved exclusively in related Peptostreptococcaeace family members, our results contribute to a growing body of work indicating that C. difficile has evolved distinct mechanisms for controlling the exit from dormancy relative to B. subtilis and other spore-forming organisms.

  6. Phospholipase C delta regulates germination of Dictyostelium spores

    NARCIS (Netherlands)

    Van Dijken, P.; Van Haastert, PJM

    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

  7. Phospholipase C delta regulates germination of Dictyostelium spores

    NARCIS (Netherlands)

    Van Dijken, P.; Van Haastert, PJM

    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 i

  8. Fungal specificity bottlenecks during orchid germination and development.

    Science.gov (United States)

    Bidartondo, Martin I; Read, David J

    2008-08-01

    Fungus-subsidized growth through the seedling stage is the most critical feature of the life history for the thousands of mycorrhizal plant species that propagate by means of 'dust seeds.' We investigated the extent of specificity towards fungi shown by orchids in the genera Cephalanthera and Epipactis at three stages of their life cycle: (i) initiation of germination, (ii) during seedling development, and (iii) in the mature photosynthetic plant. It is known that in the mature phase, plants of these genera can be mycorrhizal with a number of fungi that are simultaneously ectomycorrhizal with the roots of neighbouring forest trees. The extent to which earlier developmental stages use the same or a distinctive suite of fungi was unclear. To address this question, a total of 1500 packets containing orchid seeds were buried for up to 3 years in diverse European forest sites which either supported or lacked populations of helleborine orchids. After harvest, the fungi associated with the three developmental stages, and with tree roots, were identified via cultivation-independent molecular methods. While our results show that most fungal symbionts are ectomycorrhizal, differences were observed between orchids in the representation of fungi at the three life stages. In Cephalanthera damasonium and C. longifolia, the fungi detected in seedlings were only a subset of the wider range seen in germinating seeds and mature plants. In Epipactis atrorubens, the fungi detected were similar at all three life stages, but different fungal lineages produced a difference in seedling germination performance. Our results demonstrate that there can be a narrow checkpoint for mycorrhizal range during seedling growth relative to the more promiscuous germination and mature stages of these plants' life cycle.

  9. Monitoring of fungal spores in the indoor air of preschool institution facilities in Novi Sad

    Directory of Open Access Journals (Sweden)

    Novaković Milana S.

    2013-01-01

    Full Text Available Fungal spores can cause a range of health problems in humans such as respiratory diseases and mycotoxicoses. Since children are the most vulnerable, the presence of fungal spores in the facilities of preschool and school institutions should be investigated readily. In order to estimate air contamination by fungal spores, air sampling was conducted in eight facilities of the preschool institution in Novi Sad during February and March, 2007. Sedimentation plate method was used for the detection of viable fungal spores, mostly being members of subdv. Deuteromycota (Fungi imperfecti. In 32 samples a total of 148 colonies were developed, among which five genera were identified: Penicillium, Cladosporium, Aspergillus, Alternaria and Acremonium while non-sporulating fungal colonies were labeled as sterile mycelia. Most frequently recorded genera were Penicillium with 46 colonies and Cladosporium with 44 colonies. The genera Aspergillus and Alternaria were represented with 3 colonies each and Acremonium with only 1 colony. The greatest number of colonies emerged in the samples from the day care facilities “Vendi” (58 colonies and “Panda” (49 colonies. Most diverse samples were obtained from the day care center “Zvončica”, with presence of all identified genera. These results showed notable presence of fungal spores in the indoor air of Preschool institution facilities and indicated the need for further, more complete seasonal research. Obtained information is considered useful for the evaluation of potential mycofactors that endanger health of children. [Projekat Ministarstva nauke Republike Srbije, br. III43002

  10. The role of a purine-specific nucleoside hydrolase in spore germination of Bacillus thuringiensis.

    Science.gov (United States)

    Liang, Liang; He, Xihong; Liu, Gang; Tan, Huarong

    2008-05-01

    A homologous gene (iunH) of a putative nucleoside hydrolase (NH), which had been identified from the exosporia of Bacillus cereus and Bacillus anthracis spores, was cloned from Bacillus thuringiensis subsp. kurstaki. Disruption of iunH did not affect the vegetative growth and sporulation of Bacillus thuringiensis, but promoted both inosine- and adenosine-induced spore germination. The inosine- or adenosine-induced germination rate decreased when the wild-type iunH gene was overexpressed in Bacillus thuringiensis. The iunH gene product was characterized as a purine-specific NH. The kinetic parameters of IunH with inosine as substrate were K(m)=399+/-115 microM, k(cat)=48.9+/-8.5 s(-1) and k(cat)/K(m)=1.23 x 10(5) M(-1) s(-1). The optimal pH and temperature for IunH were found to be pH 6 and 80 degrees C. Meanwhile, the specific activity of inosine hydrolase in intact spores of the wild-type strain with inosine as substrate was 2.89+/-0.23x10(-2) micromol min(-1) (mg dry wt)(-1). These results indicate that IunH is important in moderating inosine- or adenosine-induced germination of Bacillus thuringiensis spores.

  11. Surface tension propulsion of fungal spores by use of microdroplets

    CERN Document Server

    Noblin, Xavier; Dumais, Jacques

    2010-01-01

    Many edible mushrooms eject their spores (about 10 microns in size) at high speed (about 1 m/s) using surface tension forces in a few microseconds. Basically the coalescence of a droplet with the spore generates the necessary momentum to eject the spore. We have detailed this mechanism in \\cite{noblin2}. In this article, we give some details about the high speed movies (up to 250000 fps) of mushrooms' spores ejection attached to this submission. This video was submitted as part of the Gallery of Fluid Motion 2010 which is showcase of fluid dynamics videos.

  12. Fungal spore content of the atmosphere of the Cave of Nerja (southern Spain): diversity and origin.

    Science.gov (United States)

    Docampo, Silvia; Trigo, M Mar; Recio, Marta; Melgar, Marta; García-Sánchez, José; Cabezudo, Baltasar

    2011-01-15

    Fungal spores are of great interest in aerobiology and allergy due to their high incidence in both outdoor and indoor environments and their widely recognized ability to cause respiratory diseases and other pathologies. In this work, we study the spore content of the atmosphere of the Cave of Nerja, a karstic cavity and an important tourist attraction situated on the eastern coast of Malaga (southern Spain), which receives more than half a million visitors every year. This study was carried out over an uninterrupted period of 4 years (2002-2005) with the aid of two Hirst-type volumetric pollen traps (Lanzoni VPPS 2000) situated in different halls of the cave. In the atmosphere of the Cave of Nerja, 72 different spore types were detected during the studied period and daily mean concentrations of up to 282,195 spores/m(3) were reached. Thirty-five of the spore types detected are included within Ascomycota and Basidiomycota (19 and 16 types, respectively). Of the remaining spore types, 32 were categorized within the group of so-called imperfect fungi, while Oomycota and Myxomycota were represented by 2 and 3 spore types, respectively. Aspergillus/Penicillium was the most abundant spore type with a yearly mean percentage that represented 50% of the total, followed by Cladosporium. Finally, the origin of the fungal spores found inside the cave is discussed on the basis of the indoor/outdoor concentrations and the seasonal behaviour observed. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. 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.

    Wind-blown dry fungal spores and mycelial fragments from the nearest landmass or terrestrial run-off may find their way to the deep sea by hitching a ride on other sinking detrital particles. Once in the deep, they are affected by elevated...

  14. Pyrimidine dimer formation and germination of UV-irradiated spores of Dictyostelium discoideum NC-4 and. gamma. s-13

    Energy Technology Data Exchange (ETDEWEB)

    Nozu, K.; Ohnishi, T.; Okaichi, K. (Nara Medical Univ., Kashihara (Japan))

    1982-04-01

    Survival, UV-photoproducts and germination of UV-irradiated spores of Dictyostelium discoideum were studied on two strains, NC-4 and ..gamma..s-13. The spores of NC-4 are about 35 times more resistant to UV than ..gamma..s-13 spores at 10% survival. Pyrimidine dimers were formed in UV-irradiated spores in both strains. No photoproducts other than pyrimidine dimers were detected. The formation of pyrimidine dimers in spores was about 2% in both strains at 800 J/m/sup 2/. In the germination of spores, the conversion of spores into swollen spores was not affected by UV in both strains, but the emergence of amoebae from the swollen spores was suppressed, which was more distinctive in ..gamma..s-13 spores than in NC-4 spores. The emerged amoebae from the UV-irradiated NC-4 spores were viable, while those from the ..gamma..s-13 spores were inviable even when they succeeded in emergence.

  15. High fungal spore burden with predominance of Aspergillus in hospital air of a tertiary care hospital in Chandigarh

    Directory of Open Access Journals (Sweden)

    S M Rudramurthy

    2016-01-01

    Full Text Available The prevalence of fungal spores in the hospital air is essential to understand the hospital-acquired fungal infections. Air conditioners (ACs used in hospitals may either reduce spores in air or be colonised by fungi and aid in its dissemination. The present study was conducted to assess the fungal spore burden in AC and non-AC areas. We found a high fungal spore count in air irrespective of whether the area was AC or non-AC. The most predominant species isolated were Aspergillus flavus and Aspergillus fumigatus. Such high concentrations of pathogenic fungi in air may predispose individuals to develop disease.

  16. Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA(2mob) 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 Tn1546 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

  17. High Pressure Germination of Bacillus subtilis Spores with Alterations in Levels and Types of Germination Proteins

    Science.gov (United States)

    2014-01-01

    a rapidly growing non thermal food processing technology that ensures the safety of meat , fruit juice and seafood products , extends product shelf...perfringens spores in meat products . Food Microbiol 26, 272 277. Behravan, J., Chirakkal, H., Masson, A. and Moir, A. (2000) Mutations in the gerP locus...significant agents of food spoilage and food borne disease, and the extreme resistance properties of these spores make them a major concern for the food

  18. Survival and Germinability of Bacillus subtilis Spores Exposed to Simulated Mars Solar Radiation: Implications for Life Detection and Planetary Protection

    Science.gov (United States)

    Tauscher, Courtney; Schuerger, Andrew C.; Nicholson, Wayne L.

    2006-08-01

    Bacterial spores have been considered as microbial life that could survive interplanetary transport by natural impact processes or human spaceflight activity. Deposition of terrestrial microbes or their biosignature molecules onto the surface of Mars could negatively impact life detection experiments and planetary protection measures. Simulated Mars solar radiation, particularly the ultraviolet component, has been shown to reduce spore viability, but its effect on spore germination and resulting production of biosignature molecules has not been explored. We examined the survival and germinability of Bacillus subtilis spores exposed to simulated martian conditions that include solar radiation. Spores of B. subtilis that contain luciferase resulting from expression of an sspB-luxAB gene fusion were deposited on aluminum coupons to simulate deposition on spacecraft surfaces and exposed to simulated Mars atmosphere and solar radiation. The equivalent of 42 min of simulated Mars solar radiation exposure reduced spore viability by nearly 3 logs, while germination-induced bioluminescence, a measure of germination metabolism, was reduced by less than 1 log. The data indicate that spores can retain the potential to initiate germination-associated metabolic processes and produce biological signature molecules after being rendered nonviable by exposure to Mars solar radiation.

  19. A combination of a SEM technique and X-ray microanalysis for studying the spore germination process of Clostridium tyrobutyricum.

    Science.gov (United States)

    Bassi, Daniela; Cappa, Fabrizio; Cocconcelli, Pier Sandro

    2009-06-01

    Clostridium tyrobutyricum is an anaerobic bacterium responsible for late blowing defects during cheese ripening and it is of scientific interest for biological hydrogen production. A scanning electron microscopy (SEM) coating technique and X-ray microanalysis were developed to analyze the architecture and chemical composition of spores upon germination in response to environmental changes. In addition, we investigated the effects of different compounds on this process. Agents and environmental conditions inducing germination were characterized monitoring changes in optical density (OD). Among all tested conditions, the greatest drop in OD(625) (57.4%) was obtained when spores were incubated in l-alanine/l-lactate buffer, pH 4.6. In addition, a carbon-coating SEM technique and X-ray microanalysis were used to observe the architecture of spores and to examine calcium dipicolinate release. Conditions inducing C. tyrobutyricum spore germination were identified and SEM X-ray microanalysis clearly distinguished germinating from dormant spores. We confirmed that calcium dipicolinate release is one of the first events occurring. These microscopy methods could be considered sensitive tools for evaluating morphological and chemical changes in spores of C. tyrobutyricum during the initial phase of germination. Information gathered from this work may provide new data for further research on germination.

  20. Nanoceria and bulk cerium oxide effects on the germination of asplenium adiantum-nigrum spores

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Garay, A.; Pintos, B.; Manzanera, J.A.; Prada, C.; Martin, L.; Gabriel y Galan, J.M.

    2016-07-01

    Aim of the study: The effect of cerium oxide engineered nanoparticles on the spore germination of the fern. Asplenium adiantum-nigrum. Area of study: France, Britanny Region, Finistére Department, Plougonvelin, in rocks near the sea. Material and methods: Asplenium spores were cultured in vitro on agar medium with Nano-CeO2 (less than 25 nm particle size) and bulk-CeO2. The addition of each nano- and bulk particles ranged from 0 to 3000 mg L-1. Observations on rhizoidal and prothallial cells during first stages of gametophyte development were made. The No-Observed-Adverse-Effect concentration (NOAEC) and Lowest-Observed-Adverse-Effect-Concentration (LOEC) values for spore germination rate data were analyzed. Main results: Germination was speeded up by 100 to 2000 mg L-1 nanoceria, while bulk cerium oxide had the same effect for 500 to 200 mg L-1 concentrations. Present results showed cellular damage in the protonema while rhizoid cells seemed not to be affected, as growth and membrane integrity remained. Research highlights: Both nanosized and bulk cerium oxide are toxic for the fern Asplenium adiantum-nigrum, although diverse toxicity patterns were shown for both materials. Diverse toxic effects have been observed: chloroplast membrane damage and lysis, cell wall and membrane disruption which leads to cell lysis; and alterations in morphology and development. (Author)

  1. Nanoceria and bulk cerium oxide effects on the germination of asplenium adiantum-nigrum spores

    Directory of Open Access Journals (Sweden)

    Aranzazu Gomez-Garay

    2016-12-01

    Full Text Available Aim of study: The effect of cerium oxide engineered nanoparticles on the spore germination of the fern. Asplenium adiantum-nigrum. Area of study: France, Britanny Region, Finistére Department, Plougonvelin, in rocks near the sea. Material and methods: Asplenium spores were cultured in vitro on agar medium with Nano-CeO2 (less than 25 nm particle size and bulk-CeO2. The addition of each nano- and bulk particles ranged from 0 to 3000 mg L-1. Observations on rhizoidal and prothallial cells during first stages of gametophyte development were made. The No-Observed-Adverse-Effect concentration (NOAEC and Lowest-Observed-Adverse-Effect-Concentration (LOEC values for spore germination rate data were analyzed.  Main results: Germination was speeded up by 100 to 2000 mg L-1 nanoceria, while bulk cerium oxide had the same effect for 500 to 200 mg L-1 concentrations. Present results showed cellular damage in the protonema while rhizoid cells seemed not to be affected, as growth and membrane integrity remained. Research highlights: Both nanosized and bulk cerium oxide are toxic for the fern Asplenium adiantum-nigrum, although diverse toxicity patterns were shown for both materials. Diverse toxic effects have been observed: chloroplast membrane damage and lysis, cell wall and membrane disruption which leads to cell lysis; and alterations in morphology and development. Keywords: Nanoparticles; rhizoid; prothallus; chloroplast; fern.

  2. Inhibition of Ageratina adenophora on Spore Germination and Gametophyte Development of Macrothelypteris torresiana

    Institute of Scientific and Technical Information of China (English)

    Kai-Mei Zhang; Lei Shi; Chuang-Dao Jiang; Zhen-Yu Li

    2008-01-01

    Allalopathy of Ageratina adenophora plays an important role in its invasion. However, we have little knowledge of its allelpathic effects on ferns. In Petri dish bioassays, the inhibitory potential of aqueous leachates from roots, stems and leaves of A. adenophora was studied on the spore germination and gametophyte development of Macrothelypteris torresiana. All leachates Inhibited the spore germination and growth of the first rhizoid of M. torresiana and inhibitory effects Increased with increasing leachate concentrations. Root leachates proved most inhibitory. Gametophyte rhizoids of M. torresiana treated with stem and leaf leachates ofA. adenophora were erect, which was similar to those of the control. However, gametophyte rhizoids of M. torresiana treated with root leachates of A. adenophora were erect, but also curving or swollen. Moreover, curving and swollen rhizoids Increased with Increasing concentrations. As time went by, rhizoids treated with root leachates were not so curved and the swelling almost disappeared. Possible causes are discussed in the present study. The increasing concentrations of leaf leachates also delayed the stages of gametophyte development. With the treatment of root leachates, the delay was more obvious. Thus A. adenophora inhibited the spore germination and gametophyte development of M. torresiana and the root leachates were most inhibitory.

  3. Sporulation environment of emetic toxin-producing Bacillus cereus strains determines spore size, heat resistance and germination capacity

    NARCIS (Netherlands)

    Voort, van der M.; Abee, T.

    2013-01-01

    Aim Heat resistance, germination and outgrowth capacity of Bacillus cereus spores in processed foods are major factors in causing the emetic type of gastrointestinal disease. In this study, we aim to identify the impact of different sporulation conditions on spore properties of emetic toxin-producin

  4. Sporulation environment of emetic toxin-producing Bacillus cereus strains determines spore size, heat resistance and germination capacity

    NARCIS (Netherlands)

    Voort, van der M.; Abee, T.

    2013-01-01

    Aim Heat resistance, germination and outgrowth capacity of Bacillus cereus spores in processed foods are major factors in causing the emetic type of gastrointestinal disease. In this study, we aim to identify the impact of different sporulation conditions on spore properties of emetic

  5. Characterization of bacterial spore germination using phase-contrast and fluorescence microscopy, Raman spectroscopy and optical tweezers.

    Science.gov (United States)

    Kong, Lingbo; Zhang, Pengfei; Wang, Guiwen; Yu, Jing; Setlow, Peter; Li, Yong-qing

    2011-05-01

    This protocol describes a method combining phase-contrast and fluorescence microscopy, Raman spectroscopy and optical tweezers to characterize the germination of single bacterial spores. The characterization consists of the following steps: (i) loading heat-activated dormant spores into a temperature-controlled microscope sample holder containing a germinant solution plus a nucleic acid stain; (ii) capturing a single spore with optical tweezers; (iii) simultaneously measuring phase-contrast images, Raman spectra and fluorescence images of the optically captured spore at 2- to 10-s intervals; and (iv) analyzing the acquired data for the loss of spore refractility, changes in spore-specific molecules (in particular, dipicolinic acid) and uptake of the nucleic acid stain. This information leads to precise correlations between various germination events, and takes 1-2 h to complete. The method can also be adapted to use multi-trap Raman spectroscopy or phase-contrast microscopy of spores adhered on a cover slip to simultaneously obtain germination parameters for multiple individual spores.

  6. Solving the aerodynamics of fungal flight: how air viscosity slows spore motion.

    Science.gov (United States)

    Fischer, Mark W F; Stolze-Rybczynski, Jessica L; Davis, Diana J; Cui, Yunluan; Money, Nicholas P

    2010-01-01

    Viscous drag causes the rapid deceleration of fungal spores after high-speed launches and limits discharge distance. Stokes' law posits a linear relationship between drag force and velocity. It provides an excellent fit to experimental measurements of the terminal velocity of free-falling spores and other instances of low Reynolds number motion (Reprojectile sizes, launch speeds, and discharge distances, from microscopic mushroom ballistospores discharged at 10 m s(-1) and travel as far as 2.5m (Re>100).

  7. Ectomycorrhizal fungal spore bank recovery after a severe forest fire: some like it hot.

    Science.gov (United States)

    Glassman, Sydney I; Levine, Carrie R; DiRocco, Angela M; Battles, John J; Bruns, Thomas D

    2016-05-01

    After severe wildfires, pine recovery depends on ectomycorrhizal (ECM) fungal spores surviving and serving as partners for regenerating forest trees. We took advantage of a large, severe natural forest fire that burned our long-term study plots to test the response of ECM fungi to fire. We sampled the ECM spore bank using pine seedling bioassays and high-throughput sequencing before and after the California Rim Fire. We found that ECM spore bank fungi survived the fire and dominated the colonization of in situ and bioassay seedlings, but there were specific fire adapted fungi such as Rhizopogon olivaceotinctus that increased in abundance after the fire. The frequency of ECM fungal species colonizing pre-fire bioassay seedlings, post-fire bioassay seedlings and in situ seedlings were strongly positively correlated. However, fire reduced the ECM spore bank richness by eliminating some of the rare species, and the density of the spore bank was reduced as evidenced by a larger number of soil samples that yielded uncolonized seedlings. Our results show that although there is a reduction in ECM inoculum, the ECM spore bank community largely remains intact, even after a high-intensity fire. We used advanced techniques for data quality control with Illumina and found consistent results among varying methods. Furthermore, simple greenhouse bioassays can be used to determine which fungi will colonize after fires. Similar to plant seed banks, a specific suite of ruderal, spore bank fungi take advantage of open niche space after fires.

  8. Analysis of the Effects of a gerP Mutation on the Germination of Spores of Bacillus subtilis

    Science.gov (United States)

    2012-11-01

    defective in these spores. The original gerP mutation was in the gerPC gene, the third gene in the likely hexacistronic gerP operon ; a similar operon is...present in other Bacillales species. Mutations in individual genes of the B. subtilis gerP operon also reduce spore germination with nutrient germinants...but do not reduce spore viability, and deletion of the whole operon gives the same general phenotype as do mutations in individual gerP genes. The B

  9. Early quantitative method for measuring germination in non-green spores of Dryopteris paleacea using an epifluorescence-microscope technique

    Science.gov (United States)

    Scheuerlein, R.; Wayne, R.; Roux, S. J.

    1988-01-01

    A method is described to determine germination by blue-light excited red fluorescence in the positively photoblastic spores of Dryopteris paleacea Sw. This fluorescence is due to chlorophyll as evidenced from 1) a fluorescence-emission spectrum in vivo, where a bright fluorescence around 675 nm is obtained only in red light (R)-irradiated spores and 2) in vitro measurements with acetone extracts prepared from homogenized spores. Significant amounts of chlorophyll can be found only in R-treated spores; this chlorophyll exhibits an emission band around 668 nm, when irradiated with 430 nm light at 21 degrees C. Compared to other criteria for germination, such as swelling of the cell, coat splitting, greening, and rhizoid formation, which require longer periods after induction for their expression, chlorophyll fluorescence can be used to quantify germination after two days. This result is confirmed by fluence-response curves for R-induced spore germination; the same relationship between applied R and germination is obtained by the evaluation with the epifluorescence method 2 days after the light treatment as compared with the evaluation with bright-field microscopy 5 days after the inducing R. Using this technique we show for the first time that Ca2+ contributes to the signal-transduction chain in phytochrome-mediated chlorophyll synthesis in spores of Dryopteris paleacea.

  10. Physiological role of germicidins in spore germination and hyphal elongation in Streptomyces coelicolor A3(2).

    Science.gov (United States)

    Aoki, Yuu; Matsumoto, Daisuke; Kawaide, Hiroshi; Natsume, Masahiro

    2011-09-01

    Four germicidin homologs were isolated from a liquid culture of Streptomyces coelicolor A3(2). These were identified as germicidins A, B and C, and surugapyrone A (germicidin D). Absolute stereochemistry of the chiral center in germicidins A and C is determined to be S. All germicidins inhibited germination of S. coelicolor A3(2) spores above 1 μg ml(-1). S. coelicolor A3(2) spores collected from a single petri dish (9 cm i.d.) contained 5.4 μg of germicidin A (-2.7 × 10(-14) g per spore), which accounts for 2.3% of the spore extract, and contents of germicidins B, C and D were 0.2-0.8 μg. The activity of the spore extract corresponded well with the sum of the activity of each germicidin, which was estimated from the content and dose-response curve, which indicates that germicidins functions as self-germination inhibitors in S. coelicolor A3(2). Inhibitory action of germicidin A on spore germination was reversible and germicidin A inhibited not only spore germination but also hyphal elongation.

  11. 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

  12. 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.

  13. Hexane abatement and spore emission control in a fungal biofilter-photoreactor hybrid unit.

    Science.gov (United States)

    Saucedo-Lucero, J O; Quijano, G; Arriaga, S; Muñoz, R

    2014-07-15

    The performance of a fungal perlite-based biofilter coupled to a post-treatment photoreactor was evaluated over 234 days in terms of n-hexane removal, emission and deactivation of fungal spores. The biofilter and photoreactor were operated at gas residence times of 1.20 and 0.14min, respectively, and a hexane loading rate of 115±5gm(-3)h(-1). Steady n-hexane elimination capacities of 30-40gm(-3)h(-1) were achieved, concomitantly with pollutant mineralization efficiencies of 60-90%. No significant influence of biofilter irrigation frequency or irrigation nitrogen concentration on hexane abatement was recorded. Photolysis did not support an efficient hexane post-treatment likely due to the short EBRT applied in the photoreactor, while overall hexane removal and mineralization enhancements of 25% were recorded when the irradiated photoreactor was packed with ZnO-impregnated perlite. However, a rapid catalyst deactivation was observed, which required a periodic reactivation every 48h. Biofilter irrigation every 3 days supported fungal spore emissions at concentrations ranging from 2.4×10(3) to 9.0×10(4)CFUm(-3). Finally, spore deactivation efficiencies of ≈98% were recorded for the photolytic and photocatalytic post-treatment processes. This study confirmed the potential of photo-assisted post-treatment processes to mitigate the emission of hazardous fungal spores and boost the abatement performance of biotechnologies.

  14. Detection of Fungal Spores Using a Generic Surface Plasmon Resonance Immunoassay

    DEFF Research Database (Denmark)

    Skottrup, Peter Durand; Hearty, Stephen; Frøkiær, Hanne

    2007-01-01

    This paper describes a biosensor-based method for detection of fungal spores using Surface Plasmon Resonance (SPR). The approach involves the use of a mouse monoclonal antibody (Pst mAb8) and a SPR sensor for label-free detection of urediniospores from the model organism Puccinia striiformis f.sp...

  15. Demulsification of crude oil-in-water emulsions by means of fungal spores

    Science.gov (United States)

    Vallejo-Cardona, Alba Adriana; Martínez-Palou, Rafael; Chávez-Gómez, Benjamín; García-Caloca, Graciela; Guerra-Camacho, Jairo; Cerón-Camacho, Ricardo; Reyes-Ávila, Jesús; Karamath, James Robert

    2017-01-01

    The present feature describes for the first time the application of spores from Aspergillus sp. IMPMS7 to break out crude oil-in-water emulsions (O/W). The fungal spores were isolated from marine sediments polluted with petroleum hydrocarbons. The spores exhibited the ability to destabilize different O/W emulsions prepared with medium, heavy or extra-heavy Mexican crude oils with specific gravities between 10.1 and 21.2°API. The isolated fungal spores showed a high hydrophobic power of 89.3 ± 1.9% and with 2 g of spores per liter of emulsion, the half-life for emulsion destabilization was roughly 3.5 and 0.7 h for extra-heavy and medium crude oil, respectively. Then, the kinetics of water separation and the breaking of the O/W emulsion prepared with heavy oil through a spectrofluorometric technique were studied. A decrease in the fluorescence ratio at 339 and 326 nm (I339/I326) was observed in emulsions treated with spores, which is similar to previously reported results using chemical demulsifiers. PMID:28234917

  16. Distribution of sterols in the fungi. I - Fungal spores

    Science.gov (United States)

    Weete, J. D.; Laseter, J. L.

    1974-01-01

    Mass spectrometry was used to examine freely extractable sterols from spores of several species of fungi. Ergosterol was the most common sterol produced by any individual species, but it was completely absent from two species belonging to apparently distantly related groups of fungi: the aquatic Phycomycetes and the rust fungi. This fact could have taxonomic or phylogenetic implications. The use of glass capillary columns in the resolution of the sterols is shown to eliminate some of the difficulty inherent in this process.

  17. Distribution of sterols in the fungi. I - Fungal spores

    Science.gov (United States)

    Weete, J. D.; Laseter, J. L.

    1974-01-01

    Mass spectrometry was used to examine freely extractable sterols from spores of several species of fungi. Ergosterol was the most common sterol produced by any individual species, but it was completely absent from two species belonging to apparently distantly related groups of fungi: the aquatic Phycomycetes and the rust fungi. This fact could have taxonomic or phylogenetic implications. The use of glass capillary columns in the resolution of the sterols is shown to eliminate some of the difficulty inherent in this process.

  18. The effect of rifampicin on the developmental phases of germinating spores of Clostridum sp., MSp+.

    Science.gov (United States)

    Hawirko, R Z; Bhatnagar, P K; Chung, K L; Chow, C T

    1977-12-01

    The effect of rifampicin on the developmental phases of germinating spores of Clostridium botulinum, MSp+, has been studied. At sublethal concentrations of rifampicin (0.05 ng/ml) the time periods required for outgrowth and vegetative growth was significantly prolonged because of the inhibition of RNA and protein synthesis. However, rifampicin had essentially no effect on DNA synthesis or on subsequent spore formation. Chemical analyses showed that the amount of protein present in vegetative cells of the rifampicin-treated cultures was twice as great as in the untreated cultures but the total protein content of endospores was the same in both cases. It was revealed in ultrastructural studies of rifampicin (0.1 ng/ml) treated cultures, examined after 22 h, that septum formation and normal cell division of the emerging cell was blocked and a few cells showed constriction which produced one normal and one protoplast-like daughter cell.

  19. Germination-independent induction of cellular immune response by Bacillus subtilis spores displaying the C fragment of the tetanus toxin.

    Science.gov (United States)

    Mauriello, Emilia M F; Cangiano, Giuseppina; Maurano, Francesco; Saggese, Virgilio; De Felice, Maurilio; Rossi, Mauro; Ricca, Ezio

    2007-01-15

    Bacillus subtilis spores displaying the tetanus toxin fragment C (TTFC) on their surface have been previously shown to induce the production of specific IgG and secretory IgA in mice immunized through the oral or nasal route. Aim of this study was to analyze whether these spores were also able to induce cellular immunity, and whether such immune response was dependent on spore germination in the animal gastro-intestinal tract (GIT). We first developed a germination defective strain of B. subtilis unable to produce viable cells inside the mouse GIT. Germination-defective and congenic wild-type spores both expressing TTFC on their surface were then used to orally immunize Balb/C mice. Both types of spores induced spleen and mesenteric lymph nodes cell proliferation as well as production of IFNgamma but not of IL-4 and IL-10 in both districts. Our results indicate that recombinant spores preferentially induce a strong cell-mediated immune response with a Th1 phenotype, independently from their ability to germinate in the GIT.

  20. 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.

  1. Permeabilization and inhibition of the germination of spores of Aspergillus niger for gluconic acid production from glucose.

    Science.gov (United States)

    Ramachandran, Sumitra; Fontanille, Pierre; Pandey, Ashok; Larroche, Christian

    2008-07-01

    In this study, the role of citral to permeabilize the spores of Aspergillus niger and replace sodium azide in the bioconversion medium was studied. Further, characterization of glucose oxidase of spores was carried out by exposing both permeabilized and unpermeabilized spores to different pressures (1, 2, 2.7 kb) and temperatures (60, 70, 80, 90 degrees C). Unpermeabilized spores after exposure to high temperatures were permeabilized by freezing before using as catalyst in the bioconversion reaction. Results showed that citral permeabilized the spores and could inhibit spore germination in the bioconversion medium. Rate of reaction was significantly increased from 1.5 to 4.35 g/Lh which was higher than the commercial glucose oxidase 2g/Lh). Glucose oxidase activity of A. niger was resistant to pressure. However, pressure treatment could not permeabilize them. Behaviour of fresh and permeabilized spores to temperature varied significantly. Glucose oxidase activity of fresh spores exposed to high temperature was unaffected at 70 degrees C till 15 min and 84% of relative activity was retained even after 1h at 70 degrees C while permeabilized spore got inactivated at 70 degrees C for 15 min, which followed the same pattern as commercial glucose oxidase. Cellular membrane integrity was lost due to permeabilization by freezing which resulted in heat-inactivation of glucose oxidase when spores were permeabilized before heat treatment. Thus, glucose oxidase of spore remains heat stable when unpermeabilized and active while permeabilized and its reaction rate is higher than the commercial glucose oxidase.

  2. Incorporation of Specific Fatty Acid Precursors During Spore Germination and Outgrowth in Bacillus thuringiensis

    Science.gov (United States)

    Nickerson, Kenneth W.; Bulla, Lee A.

    1980-01-01

    The selective incorporation of precursors specific for individual fatty acids in germinating and outgrowing spores of Bacillus thuringiensis is described. The specific precursors utilized were [14C]butyrate, -isobutyrate, -valerate, and -isovalerate, which were incorporated into even-numbered normal-chain isomers, even-numbered iso-isomers, odd-numbered normal-chain acids, and odd-numbered isohomologs, respectively. This preferential incorporation by B. thuringiensis allows the terminal carbons of specific normal and branched-chain fatty acids, contained within the cytoplasmic membrane, to be labeled with 14C and, potentially, 13C. PMID:16345590

  3. Hexane abatement and spore emission control in a fungal biofilter-photoreactor hybrid unit

    Energy Technology Data Exchange (ETDEWEB)

    Saucedo-Lucero, J.O. [Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid (Spain); IPICyT, Instituto Potosino de Investigación Científica y Tecnológica, División de Ciencias Ambientales, Camino a la Presa San José No. 2055, C.P., 78216 San Luis Potosí (Mexico); Quijano, G. [Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid (Spain); Arriaga, S. [IPICyT, Instituto Potosino de Investigación Científica y Tecnológica, División de Ciencias Ambientales, Camino a la Presa San José No. 2055, C.P., 78216 San Luis Potosí (Mexico); Muñoz, R., E-mail: mutora@iq.uva.es [Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid (Spain)

    2014-07-15

    Highlights: • A fungal biofilter/photoreactor was evaluated in terms of hexane and spore removal. • Biofilter supported elimination capacities of ≈35 g m{sup −3} h{sup −1} and CO{sub 2} yields of ≈75%. • The photocatalytic process slightly boosted the hexane abatement performance. • Biofilter emitted fungal spores at concentrations of 2.4 × 10{sup 3}–9.0 × 10{sup 4} CFU m{sup −3}. • Photo-assisted post-treatments resulted in spore deactivation efficiencies of 98%. - Abstract: The performance of a fungal perlite-based biofilter coupled to a post-treatment photoreactor was evaluated over 234 days in terms of n-hexane removal, emission and deactivation of fungal spores. The biofilter and photoreactor were operated at gas residence times of 1.20 and 0.14 min, respectively, and a hexane loading rate of 115 ± 5 g m{sup −3} h{sup −1}. Steady n-hexane elimination capacities of 30–40 g m{sup −3} h{sup −1} were achieved, concomitantly with pollutant mineralization efficiencies of 60–90%. No significant influence of biofilter irrigation frequency or irrigation nitrogen concentration on hexane abatement was recorded. Photolysis did not support an efficient hexane post-treatment likely due to the short EBRT applied in the photoreactor, while overall hexane removal and mineralization enhancements of 25% were recorded when the irradiated photoreactor was packed with ZnO-impregnated perlite. However, a rapid catalyst deactivation was observed, which required a periodic reactivation every 48 h. Biofilter irrigation every 3 days supported fungal spore emissions at concentrations ranging from 2.4 × 10{sup 3} to 9.0 × 10{sup 4} CFU m{sup −3}. Finally, spore deactivation efficiencies of ≈98% were recorded for the photolytic and photocatalytic post-treatment processes. This study confirmed the potential of photo-assisted post-treatment processes to mitigate the emission of hazardous fungal spores and boost the abatement performance of

  4. Nutrient activation of Trichoderma fungal spores for improved biocontrol activity

    Institute of Scientific and Technical Information of China (English)

    Linda Gordon Hjeljord; Arne Tronsmo

    2004-01-01

    @@ The effect of preliminary nutrient activation on the ability of conidia of the antagonist Trichoderma harzianum P1 (ThP1) to suppress Botrytis cinerea was investigated in laboratory, greenhouse and field trials. Preliminary nutrient activation at 21 ℃ accelerated subsequent germination of the antagonist at temperatures from 9 ℃ to 21 ℃; at ≥ 18 ℃ the germination time of preactivated ThP1conidia did not differ significantly from that of B. cinerea. When coinoculated with B. cinerea,concentrated inocula of preactivated but ungerminated ThP1 conidia reduced in vitro germination of the pathogen by ≥ 87 % at 12 ℃ to 25 ℃; initially-quiescent conidia achieved this level of suppression only at 25 ℃. Application of quiescent ThP1 conidia to detached strawberry flowers in moist chambers reduced infection by B. cinerea by ≥85 % at 24 ℃ , but only by 35 % at 12 ℃. Preactivated conidia reduced infection by ≥60% at 12 ℃. Both quiescent and preactivated conidia significantly reduced latent infection in greenhouse-grown strawberries at a mean temperture of 19 ℃, while only preactivated conidia were effective in the field at a mean temperature of 14 ℃ on the day of treatment application.

  5. Ice Nucleation of Fungal Spores from the Classes Agaricomycetes, Ustilaginomycetes, and Eurotiomycetes, and the effect on the Atmospheric Transport of these Spores

    Energy Technology Data Exchange (ETDEWEB)

    Haga, D. I.; Burrows, Susannah M.; Iannone, R.; Wheeler, M. J.; Mason, R.; Chen, J.; Polishchuk, E. A.; Poschl, U.; Bertram, Allan K.

    2014-08-26

    Ice nucleation on fungal spores may affect the frequency and properties of ice and mixed-phase clouds. We studied the ice nucleation properties of 12 different species of fungal spores chosen from three classes: Agaricomycetes, Ustilagomycetes, and Eurotiomycetes. Agaricomycetes include many types of mushroom species and are cosmopolitan all over the globe. Ustilagomycetes are agricultural pathogens and have caused widespread damage to crops. Eurotiomycetes are found on all types of decaying material and include important human allergens. We focused on these classes since they are thought to be abundant in the atmosphere and because there is very little information on the ice nucleation ability of these classes of spores in the literature. All of the fungal spores investigated were found to cause freezing of water droplets at temperatures warmer than homogeneous freezing. The cumulative number of ice nuclei per spore was 0.001 at temperatures between -19 °C and -29 °C, 0.01 between -25.5 °C and -31 °C, and 0.1 between -26 °C and -36 °C. On average, the order of ice nucleating ability for these spores is Ustilagomycetes > Agaricomycetes ≅ Eurotiomycetes. We show that at temperatures below -20 °C, all of the fungal spores studied here are less efficient ice nuclei compared to Asian mineral dust on a per surface area basis. We used our new freezing results together with data in the literature to compare the freezing temperatures of spores from the phyla Basidiomycota and Ascomycota, which together make up 98 % of known fungal species found on Earth. The data show that within both phyla (Ascomycota and Basidiomycota) there is a wide range of freezing properties, and also that the variation within a phylum is greater than the variation between the average freezing properties of the phyla. Using a global chemistry-climate transport model, we investigated whether ice nucleation on the studied spores, followed by precipitation, can influence the atmospheric

  6. Ice nucleation by fungal spores from the classes Agaricomycetes, Ustilaginomycetes, and Eurotiomycetes, and the effect on the atmospheric transport of these spores

    Science.gov (United States)

    Haga, D. I.; Burrows, S. M.; Iannone, R.; Wheeler, M. J.; Mason, R. H.; Chen, J.; Polishchuk, E. A.; Pöschl, U.; Bertram, A. K.

    2014-08-01

    We studied the ice nucleation properties of 12 different species of fungal spores chosen from three classes: Agaricomycetes, Ustilaginomycetes, and Eurotiomycetes. Agaricomycetes include many types of mushroom species and are widely distributed over the globe. Ustilaginomycetes are agricultural pathogens and have caused widespread damage to crops. Eurotiomycetes are found on all types of decaying material and include important human allergens. We focused on these classes because they are thought to be abundant in the atmosphere and because there is very little information on the ice nucleation ability of these classes of spores in the literature. All of the fungal spores investigated contained some fraction of spores that serve as ice nuclei at temperatures warmer than homogeneous freezing. The cumulative number of ice nuclei per spore was 0.001 at temperatures between -19 °C and -29 °C, 0.01 between -25.5 °C and -31 °C, and 0.1 between -26 °C and -31.5 °C. On average, the order of ice nucleating ability for these spores is Ustilaginomycetes > Agaricomycetes ≃ Eurotiomycetes. The freezing data also suggests that, at temperatures ranging from -20 °C to -25 °C, all of the fungal spores studied here are less efficient ice nuclei compared to Asian mineral dust on a per surface area basis. We used our new freezing results together with data in the literature to compare the freezing temperatures of spores from the phyla Basidiomycota and Ascomycota, which together make up 98% of known fungal species found on Earth. The data show that within both phyla (Ascomycota and Basidiomycota), there is a wide range of freezing properties, and also that the variation within a phylum is greater than the variation between the average freezing properties of the phyla. Using a global chemistry-climate transport model, we investigated whether ice nucleation on the studied spores, followed by precipitation, can influence the transport and global distributions of these spores in

  7. Rhizobacteria Selection to Enhance Spore Germination and Hyphal Length of Arbuscular Mycorrhizal Fungi in Vitro

    Directory of Open Access Journals (Sweden)

    Cecep Hidayat

    2013-04-01

    Full Text Available In natural condition, Arbuscular Mycorrhizal Fungi (AMF are surrounded by bacteria that help fungi symbiosis. The research aimed to get rhizobacteria that can act as Mycorrhiza Helper Bacteria (MHB had been held at Soil Biology and Biotechnology Laboratory Faculty of Agriculture Unpad from February to March 2012. The experimental design used was completely randomized design with 11 treatments (bo= without rhizobacteria, b1= Pseudomonas diminuta, b2 = Bacillus alvei, b3 = B. mycoides, b4 = P. malei, b5= P. diminuta + B. alvei, b6 = P. diminuta + B. mycoides, b7 = P. diminuta + P. malei, b8 = B. alvei + B. mycoides, b9 = B. alvei + P. malei, b10= B. mycoides + P. malei with 3 replications. Parameters evaluated were spore germination percentage and hyphal length of Glomus sp at 7, 14, 21, and 28 day after planting. The result showed that P. diminuta enhanced spore germination percentage and hyphal length of Glomus spas much as 224 % and 330%respectively than control. So, P. diminuta can be used as MHB.

  8. Significant contributions of fungal spores to the organic carbon and to the aerosol mass balance of the urban atmospheric aerosol

    Science.gov (United States)

    Bauer, Heidi; Schueller, Elisabeth; Weinke, Gert; Berger, Anna; Hitzenberger, Regina; Marr, Iain L.; Puxbaum, Hans

    Fungal spores are ubiquitous components of atmospheric aerosols and are therefore also contributors to the organic carbon (OC) component and to the mass of PM 10 (PM—particulate matter) aerosols. In this study we use spore counts and an experimentally derived factor of 13 pg C and of 33 pg fresh weight per spore for assessing quantitatively the contribution to OC and PM 10. The concentrations of airborne fungal spores were determined at a suburban (Schafberg) and a traffic-dominated urban site (Rinnböckstrasse) in Vienna, Austria, during spring and summer. Fungal spores OC ranged from 22 to 677 ng m -3 with a summer mean value of around 350 ng m -3 at the suburban site and 300 ng m -3 at the urban traffic site. At the suburban site fungal spores contributed on average 6% in spring and 14% in summer to aerosol OC mass concentration. At the traffic-dominated site fungal spores accounted for 2% of OC in spring and for 8% in summer. The fungal contribution to PM 10 was also notable and amounted to 3% and 7% at the suburban and to 1% and 4% at the urban site in spring and summer, respectively. Impactor measurements of OC at the suburban site showed that in summer fungal spores were predominant contributors to the coarse aerosol OC, and accounted on average for 60% of the OC in the PM 2-10 fraction. Fungal spores thus can be regarded as main components to PM 10, total OC and, most importantly, coarse OC even in urban areas.

  9. Inactivation of three genera of dominant fungal spores in groundwater using chlorine dioxide: Effectiveness, influencing factors, and mechanisms.

    Science.gov (United States)

    Wen, Gang; Xu, Xiangqian; Huang, Tinglin; Zhu, Hong; Ma, Jun

    2017-08-18

    Fungi in aquatic environments received more attention recently; therefore, the characteristics of inactivation of fungal spores by widely used disinfectants are quite important. Nonetheless, the inactivation efficacy of fungal spores by chlorine dioxide is poorly known. In this study, the effectiveness of chlorine dioxide at inactivation of three dominant genera of fungal spores isolated from drinking groundwater and the effects of pH, temperature, chlorine dioxide concentration, and humic acid were evaluated. The inactivation mechanisms were explored by analyzing the leakage of intracellular substances, the increase in extracellular adenosine triphosphate (ATP), deoxyribonucleic acid (DNA), and proteins as well as the changes in spore morphology. The kinetics of inactivation by chlorine dioxide fitted the Chick-Watson model, and different fungal species showed different resistance to chlorine dioxide inactivation, which was in the following order: Cladosporium sp.>Trichoderma sp. >Penicillium sp., which are much more resistant than Escherichia coli. Regarding the three genera of fungal spores used in this study, chlorine dioxide was more effective at inactivation of fungal spores than chlorine. The effect of disinfectant concentration and temperature was positive, and the impact of pH levels (6.0 and 7.0) was insignificant, whereas the influence of water matrices on the inactivation efficiency was negative. The increased concentration of characteristic extracellular substances and changes of spore morphology were observed after inactivation with chlorine dioxide and were due to cell wall and cell membrane damage in fungal spores, causing the leakage of intracellular substances and death of a fungal spore. Copyright © 2017. Published by Elsevier Ltd.

  10. Application of nisin and pediocin against resistance and germination of Bacillus spores in sous vide products.

    Science.gov (United States)

    Cabo, M L; Torres, B; Herrera, J J R; Bernárdez, M; Pastoriza, L

    2009-03-01

    Sous vide and other mild preservation techniques are increasingly demanded by consumers. However, spores often will survive in minimally processed foods, causing both spoilage and safety problems. The main objective of the present work was to solve an industrial spoilage problem associated with two sous vide products: mushrooms and shellfish salad. Bacillus subtilis and Bacillus licheniformis predominated as the most heat-resistant organisms isolated from mushrooms and shellfish salad, respectively. The combined effects of nisin and pediocin against resistance and germination of both Bacillus species were described by empirical equations. Whereas nisin was more effective for decreasing thermal resistance of B. subtilis spores, pediocin was more effective against B. licheniformis. However, a significant positive interaction between both biopeptides for decreasing the proportion of vegetative cells resulting from thermoresistant spores was demonstrated in later experiments, thus indicating the increased efficacy of applying high concentrations of both bacteriocins. This efficacy was further demonstrated in additional challenge studies carried out at 15 degrees C in the two sous vide products: mushrooms and shellfish salad. Whereas no vegetative cells were detected after 90 days in the presence of bacteriocins, almost 100% of the population in nontreated samples of mushrooms and shellfish salad was in the vegetative state after 17 and 43 days of storage at 15 degrees C, respectively.

  11. The relationships between air pollutants, meteorological parameters and concentration of airborne fungal spores

    Energy Technology Data Exchange (ETDEWEB)

    Grinn-Gofron, Agnieszka, E-mail: agofr@univ.szczecin.p [Department of Plant Taxonomy and Phytogeography, Faculty of Natural Science, University of Szczecin, Waska 13 Street, 71-415 Szczecin (Poland); Strzelczak, Agnieszka [Department of Food Process Engineering, Faculty of Food Science and Fisheries, West Pomeranian University of Technology, Szczecin (Poland); Wolski, Tomasz [Physical Oceanography Laboratory, University of Szczecin (Poland)

    2011-02-15

    Fungal spores are an important component of bioaerosol and also considered to act as indicator of the level of atmospheric bio-pollution. Therefore, better understanding of these phenomena demands a detailed survey of airborne particles. The objective of this study was to examine the dependence of two the most important allergenic taxa of airborne fungi - Alternaria and Cladosporium - on meteorological parameters and air pollutant concentrations during three consecutive years (2006-2008). This study is also an attempt to create artificial neural network (ANN) forecasting models useful in the prediction of aeroallergen abundance. There were statistically significant relationships between spore concentration and environmental parameters as well as pollutants, confirmed by the Spearman's correlation rank analysis and high performance of the ANN models obtained. The concentrations of Cladosporium and Alternaria spores can be predicted with quite good accuracy from meteorological conditions and air pollution recorded three days earlier. - ANN models predict airspore contents from weather conditions and air pollutant.

  12. Effect of Heavy metal stress on spore germination of Pteris confusa T. G. Walker and Pteris argyraea T. Moore

    Directory of Open Access Journals (Sweden)

    Irudayaraj V.

    2011-12-01

    Full Text Available Background: Plants have both constitutive and adaptive mechanisms for coping with the elevated metal concentrations and they are utilized to clean the polluted soil and water. Unlike angiosperms hyperaccumulators, fern hyperaccumulators are equipped with inherent biological characteristics that could be exploited in the phytoremediation strategies aimed at decontaminating polluted sites. Fern spores can be successfully used to screen the hyperaccumualting ferns and also to test the toxicity of the metal contaminated samples. Purpose of the Study: In the present study, a preliminary attempt was made to compare the tolerance capacity of the spores of two ferns; Pteris confusa T. G. Walker and Pteris argyraea T. Moore against the heavy metal zinc (Zinc sulphate. Spores of the two ferns were cultured in Knop’s liquid medium with various concentrations of zinc sulphate (0-200ppm. Results: In the case of P. confusa normal germination was observed in control, 120 ppm and 140 ppm and the germination of spores were failed in 160, 180 and 200 ppm of zinc supplemented cultures. In contrary, P. argyraea showed maximum percentage of spore germination in 140 ppm zinc supplemented cultures and the control and 120 ppm zinc sulphate supplemented cultures were failed to show the germination. The germination percentage and growth rate was decreased in high concentration of zinc sulphate. Rhizoids are showed more tolerance to heavy metal than protonema of P. argyraea. Conclusion: Difference in response of spores to the heavy metal zinc may be due the difference in the hyper-accumulating capacity of the ferns.

  13. Estimating the abundance of airborne pollen and fungal spores at variable elevations using an aircraft: how high can they fly?

    Science.gov (United States)

    Damialis, Athanasios; Kaimakamis, Evangelos; Konoglou, Maria; Akritidis, Ioannis; Traidl-Hoffmann, Claudia; Gioulekas, Dimitrios

    2017-03-01

    Airborne pollen and fungal spores are monitored mainly in highly populated, urban environments, for allergy prevention purposes. However, their sources can frequently be located outside cities’ fringes with more vegetation. So as to shed light to this paradox, we investigated the diversity and abundance of airborne pollen and fungal spores at various environmental regimes. We monitored pollen and spores using an aircraft and a car, at elevations from sea level to 2,000 m above ground, in the region of Thesssaloniki, Greece. We found a total of 24 pollen types and more than 15 spore types. Pollen and spores were detected throughout the elevational transect. Lower elevations exhibited higher pollen concentrations in only half of plant taxa and higher fungal spore concentrations in only Ustilago. Pinaceae and Quercus pollen were the most abundant recorded by airplane (>54% of the total). Poaceae pollen were the most abundant via car measurements (>77% of the total). Cladosporium and Alternaria spores were the most abundant in all cases (aircraft: >69% and >17%, car: >45% and >27%, respectively). We conclude that pollen and fungal spores can be diverse and abundant even outside the main source area, evidently because of long-distance transport incidents.

  14. Differential Inactivation of Fungal Spores in Water and on Seeds by Ozone and Arc Discharge Plasma.

    Directory of Open Access Journals (Sweden)

    Min Ho Kang

    Full Text Available Seed sterilization is essential for preventing seed borne fungal diseases. Sterilization tools based on physical technologies have recently received much attention. However, available information is very limited in terms of efficiency, safety, and mode of action. In this study, we have examined antifungal activity of ozone and arc discharge plasma, potential tools for seed sterilization. In our results, ozone and arc discharge plasma have shown differential antifungal effects, depending on the environment associated with fungal spores (freely submerged in water or infected seeds. Ozone inactivates Fusarium fujikuroi (fungus causing rice bakanae disease spores submerged in water more efficiently than arc discharge plasma. However, fungal spores associated with or infecting rice seeds are more effectively deactivated by arc discharge plasma. ROS generated in water by ozone may function as a powerful fungicidal factor. On the other hand, shockwave generated from arc discharge plasma may have greatly contributed to antifungal effects on fungus associated with rice seeds. In support of this notion, addition of ultrasonic wave in ozone generating water has greatly increased the efficiency of seed disinfection.

  15. Differential Inactivation of Fungal Spores in Water and on Seeds by Ozone and Arc Discharge Plasma

    Science.gov (United States)

    Kang, Min Ho; Pengkit, Anchalee; Choi, Kihong; Jeon, Seong Sil; Choi, Hyo Won; Shin, Dong Bum; Choi, Eun Ha; Uhm, Han Sup; Park, Gyungsoon

    2015-01-01

    Seed sterilization is essential for preventing seed borne fungal diseases. Sterilization tools based on physical technologies have recently received much attention. However, available information is very limited in terms of efficiency, safety, and mode of action. In this study, we have examined antifungal activity of ozone and arc discharge plasma, potential tools for seed sterilization. In our results, ozone and arc discharge plasma have shown differential antifungal effects, depending on the environment associated with fungal spores (freely submerged in water or infected seeds). Ozone inactivates Fusarium fujikuroi (fungus causing rice bakanae disease) spores submerged in water more efficiently than arc discharge plasma. However, fungal spores associated with or infecting rice seeds are more effectively deactivated by arc discharge plasma. ROS generated in water by ozone may function as a powerful fungicidal factor. On the other hand, shockwave generated from arc discharge plasma may have greatly contributed to antifungal effects on fungus associated with rice seeds. In support of this notion, addition of ultrasonic wave in ozone generating water has greatly increased the efficiency of seed disinfection. PMID:26406468

  16. A new chitinase-like xylanase inhibitor protein (XIP from coffee (Coffea arabica affects Soybean Asian rust (Phakopsora pachyrhizi spore germination

    Directory of Open Access Journals (Sweden)

    Mehta Angela

    2011-02-01

    Full Text Available Abstract Background Asian rust (Phakopsora pachyrhizi is a common disease in Brazilian soybean fields and it is difficult to control. To identify a biochemical candidate with potential to combat this disease, a new chitinase-like xylanase inhibitor protein (XIP from coffee (Coffea arabica (CaclXIP leaves was cloned into the pGAPZα-B vector for expression in Pichia pastoris. Results A cDNA encoding a chitinase-like xylanase inhibitor protein (XIP from coffee (Coffea arabica (CaclXIP, was isolated from leaves. The amino acid sequence predicts a (β/α8 topology common to Class III Chitinases (glycoside hydrolase family 18 proteins; GH18, and shares similarity with other GH18 members, although it lacks the glutamic acid residue essential for catalysis, which is replaced by glutamine. CaclXIP was expressed as a recombinant protein in Pichia pastoris. Enzymatic assay showed that purified recombinant CaclXIP had only residual chitinolytic activity. However, it inhibited xylanases from Acrophialophora nainiana by approx. 60% when present at 12:1 (w/w enzyme:inhibitor ratio. Additionally, CaclXIP at 1.5 μg/μL inhibited the germination of spores of Phakopsora pachyrhizi by 45%. Conclusions Our data suggests that CaclXIP belongs to a class of naturally inactive chitinases that have evolved to act in plant cell defence as xylanase inhibitors. Its role on inhibiting germination of fungal spores makes it an eligible candidate gene for the control of Asian rust.

  17. Sporulation and germination gene expression analysis of Bacillus anthracis Sterne spores in skim milk under heat and different intervention techniques

    Science.gov (United States)

    To investigate how B. anthracis Stene spores survive in milk under heat (80 degree C, 10 minutes), pasteurization (72 degree C, 15 seconds) and pasteurization plus microfiltration, the expression levels of genes that related to sporulation and germination were tested using real-time PCR assays. Tw...

  18. Mixed Production of Filamentous Fungal Spores for Preventing Soil-Transmitted Helminth Zoonoses: A Preliminary Analysis

    Directory of Open Access Journals (Sweden)

    M. S. Arias

    2013-01-01

    Full Text Available Helminth zoonoses are parasitic infections shared by humans and animals, being the soil-transmitted helminths (STHs mainly caused by roundworms (ascarids and hookworms. This study was aimed to assess the individual and/or mixed production of two helminth-antagonistic fungi, one ovicide (Mucor circinelloides and other predator (Duddingtonia flagrans. Fungi were grown both in Petri plates and in a submerged culture (composed by water, NaCl, Na2HPO4 · 12 H2O, and wheat (Triticum aestivum. A Fasciola hepatica recombinant protein (FhrAPS was incorporated to the cultures to improve fungal production. All the cultured plates showed fungal growth, without difference in the development of the fungi when grown alone or mixed. High counts of Mucor spores were produced in liquid media cultures, and no significant differences were achieved regarding single or mixed cultures, or the incorporation of the FhrAPS. A significantly higher production of Duddingtonia spores after the incorporation of the FhrAPS was observed. When analyzing the parasiticide efficacy of the fungal mixture, viability of T. canis eggs reduced to 51%, and the numbers of third stage cyathostomin larvae reduced to 4%. It is concluded, the capability of a fungal mixture containing an ovicide (Mucor and a predator species (Duddingtonia for growing together in a submerged medium containing the FhrAPS offers a very interesting tool for preventing STHs.

  19. 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.

  20. Real-time In Situ Electron Spin Resonance Measurements on Fungal Spores of Penicillium digitatum during Exposure of Oxygen Plasmas

    CERN Document Server

    Ishikawa, Kenji; Tanaka, Hiromasa; Tamiya, Kazuhiro; Hashizume, Hiroshi; Ohta, Takayuki; Ito, Masafumi; Iseki, Sachiko; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru

    2012-01-01

    We report the kinetic analysis of free radicals on fungal spores of Penicillium digitatum interacted with atomic oxygen generated plasma electric discharge using real time in situ electron spin resonance (ESR) measurements. We have obtained information that the ESR signal from the spores was observed and preliminarily assignable to semiquinone radical with a g-value of around 2.004 and a line width of approximately 5G. The decay of the signal is possibly linked to the inactivation of the fungal spore. The real-time in situ ESR has proven to be a useful method to elucidate plasma-induced surface reactions on biological specimens.

  1. Real-time in situ electron spin resonance measurements on fungal spores of Penicillium digitatum during exposure of oxygen plasmas

    Science.gov (United States)

    Ishikawa, Kenji; Mizuno, Hiroko; Tanaka, Hiromasa; Tamiya, Kazuhiro; Hashizume, Hiroshi; Ohta, Takayuki; Ito, Masafumi; Iseki, Sachiko; Takeda, Keigo; Kondo, Hiroki; Sekine, Makoto; Hori, Masaru

    2012-07-01

    We report the kinetic analysis of free radicals on fungal spores of Penicillium digitatum interacted with atomic oxygen generated plasma electric discharge using real time in situ electron spin resonance (ESR) measurements. We have obtained information that the ESR signal from the spores was observed and preliminarily assignable to semiquinone radical with a g-value of around 2.004 and a line width of approximately 5G. The decay of the signal is possibly linked to the inactivation of the fungal spore. The real-time in situ ESR has proven to be a useful method to elucidate plasma-induced surface reactions on biological specimens.

  2. A Generic Method for Fungal Spore Detection: The use of a monoclonal antibody and surface plasmon resonance

    DEFF Research Database (Denmark)

    Skottrup, Peter; Hearty, Stephen; Frøkiær, Hanne;

    2005-01-01

    This study describes a biosensing principle for detection of fungal spores using surface plasmon resonance (SPR). The approach involves the use of a monoclonal antibody (mab) and a SPR sensor for label-free detection of the model organism Puccinia striiformis f.sp. tritici (Pst) a biotrophic fungus...... binding of mab to the sensor surface was observed as the Pst urediniospore concentration was increased. The detection range for the assay was 1.7 x 106 – 5.3 x 104 spores/ml. This study describes the first use of SPR for detection of fungal spores and the generic principle has the potential to be used...

  3. Uptake of and Resistance to the Antibiotic Berberine by Individual Dormant, Germinating and Outgrowing Bacillus Spores as Monitored by Laser Tweezers Raman Spectroscopy.

    Science.gov (United States)

    Wang, Shiwei; Yu, Jing; Suvira, Milomir; Setlow, Peter; Li, Yong-qing

    2015-01-01

    Berberine, an alkaloid originally extracted from the plant Coptis chinensis and other herb plants, has been used as a pharmacological substance for many years. The therapeutic effect of berberine has been attributed to its interaction with nucleic acids and blocking cell division. However, levels of berberine entering individual microbial cells minimal for growth inhibition and its effects on bacterial spores have not been determined. In this work the kinetics and levels of berberine accumulation by individual dormant and germinated spores were measured by laser tweezers Raman spectroscopy and differential interference and fluorescence microscopy, and effects of berberine on spore germination and outgrowth and spore and growing cell viability were determined. The major conclusions from this work are that: (1) colony formation from B. subtilis spores was blocked ~ 99% by 25 μg/mL berberine plus 20 μg/mL INF55 (a multidrug resistance pump inhibitor); (2) 200 μg/mL berberine had no effect on B. subtilis spore germination with L-valine, but spore outgrowth was completely blocked; (3) berberine levels accumulated in single spores germinating with ≥ 25 μg/mL berberine were > 10 mg/mL; (4) fluorescence microscopy showed that germinated spores accumulated high-levels of berberine primarily in the spore core, while dormant spores accumulated very low berberine levels primarily in spore coats; and (5) during germination, uptake of berberine began at the time of commitment (T1) and reached a maximum after the completion of CaDPA release (Trelease) and spore cortex lysis (Tlysis).

  4. Chemo-protective effect of aqueous extract of the resurrection plant Selaginella involvens (Sw. Spring on UV-tolerance during spore germination of Pteris argyraea T. Moore

    Directory of Open Access Journals (Sweden)

    Sathiyakumar C.

    2011-12-01

    Full Text Available The present study was aimed to know the effect of aqueous extracts of the resurrection plant, Selaginella involvens (Sw. Spring on spore germination in Pteris argyraea T. Moore and also to know the ameliorating effect of the extracts on UV-Stress during spore germination of Pteris argyraea T. Moore. Based on the present study it is concluded that the extract of Selaginella involvens, shows growth promoting effect by enhancing the spore germination in Pteris argyraea. Both UV and aqueous extracts of Selaginella involvens enhances germination, but the UV stress results in both physical and morphogenetic abnormalities. It is to be noted that in the extract treated spores, the physical abnormalities are in less frequency when compared to the extract- untreated spores.

  5. Ice nucleation and its effect on the atmospheric transport of fungal spores from the classes Agaricomycetes, Ustilaginomycetes, and Eurotiomycetes

    Science.gov (United States)

    Haga, D. I.; Burrows, S. M.; Iannone, R.; Wheeler, M. J.; Mason, R.; Chen, J.; Polishchuk, E. A.; Pöschl, U.; Bertram, A. K.

    2014-02-01

    Ice nucleation on fungal spores may affect the frequency and properties of ice and mixed-phase clouds. We studied the ice nucleation properties of 12 different species of fungal spores chosen from three classes: Agaricomycetes, Ustilaginomycetes, and Eurotiomycetes. Agaricomycetes include many types of mushroom species and are cosmopolitan. Ustilaginomycetes are agricultural pathogens and have caused widespread damage to crops. Eurotiomycetes are found on all types of decaying material and include important human allergens. We focused on these classes since they are thought to be abundant in the atmosphere and because there is very little information on the ice nucleation ability of these classes of spores in the literature. All of the fungal spores investigated were found to cause freezing of water droplets at temperatures warmer than homogeneous freezing. The cumulative number of ice nuclei per spore was 0.001 at temperatures between -19 °C and -29 °C, 0.01 between -25.5 °C and -31 °C, and 0.1 between -26 °C and -36 °C. On average, the order of ice nucleating ability for these spores is Ustilaginomycetes > Agaricomycetes ≃ Eurotiomycetes. We show that at temperatures below -20 °C, all of the fungal spores studied here are less efficient ice nuclei compared to Asian mineral dust on a per surface area basis. We used our new freezing results together with data in the literature to compare the freezing temperatures of spores from the phyla Basidiomycota and Ascomycota, which together make up 98% of known fungal species found on Earth. The data show that within both phyla (Ascomycota and Basidiomycota) there is a wide range of freezing properties, and also that the variation within a phylum is greater than the variation between the average freezing properties of the phyla. Using a global chemistry-climate transport model, we investigated whether ice nucleation on the studied spores, followed by precipitation, can influence the atmospheric transport and

  6. Hummingbirds as vectors of fungal spores in Moussonia deppeana (Gesneriaceae): taking advantage of a mutualism?

    Science.gov (United States)

    Lara, Carlos; Ornelas, Juan Francisco

    2003-02-01

    Hummingbirds act as vectors of Fusarium moniliforme spores on protandrous flowers of Moussonia deppeana. The resulting interactions between the pathogen and plant-pollinator interactions were investigated in a 4-yr study to determine the pathogen's impact on host flowering phenology, flower longevity, nectar production, and fruit and seed production. We also evaluated hummingbird behavior on healthy and diseased plants and its effectiveness on spore transmission. Individual plants expressed the disease from year to year, and new infected individuals were detected every year. A fraction of the flowers in a plant expressed the disease, and this varied among and within years. Diseased plants produced more inflorescences, buds, and open healthy flowers than did healthy plants. Further, diseased plants bore proportionally fewer pistillate flowers than did healthy plants when considering only healthy flowers. Neither nectar nor fruit production differed between healthy and diseased plants, but healthy plants produced more seeds. Infected flowers were retained longer than uninfected ones, producing an additional 2 mg · μL(-1) · flower(-1) of nectar sugar. Hummingbirds visited more flowers on diseased plants than they did on healthy plants, regardless of number and sexual phase. Most pollen and spores were deposited within plants. These behavioral outcomes may promote geitonogamy and limit fungal spore mixing.

  7. Gamma, Gaussian and logistic distribution models for airborne pollen grains and fungal spore season dynamics.

    Science.gov (United States)

    Kasprzyk, I; Walanus, A

    2014-01-01

    The characteristics of a pollen season, such as timing and magnitude, depend on a number of factors such as the biology of the plant and environmental conditions. The main aim of this study was to develop mathematical models that explain dynamics in atmospheric concentrations of pollen and fungal spores recorded in Rzeszów (SE Poland) in 2000-2002. Plant taxa with different characteristics in the timing, duration and curve of their pollen seasons, as well as several fungal taxa were selected for this analysis. Gaussian, gamma and logistic distribution models were examined, and their effectiveness in describing the occurrence of airborne pollen and fungal spores was compared. The Gaussian and differential logistic models were very good at describing pollen seasons with just one peak. These are typically for pollen types with just one dominant species in the flora and when the weather, in particular temperature, is stable during the pollination period. Based on s parameter of the Gaussian function, the dates of the main pollen season can be defined. In spite of the fact that seasonal curves are often characterised by positive skewness, the model based on the gamma distribution proved not to be very effective.

  8. Semiochemicals from ex situ abiotically stressed cactus tissue: a contributing role of fungal spores?

    Science.gov (United States)

    Beck, John J; Baig, Nausheena; Cook, Daniel; Mahoney, Noreen E; Marsico, Travis D

    2014-12-24

    Semiochemicals play a central role in communication between plants and insects, such as signaling the location of a suitable host. Fungi on host plants can also play an influential role in communicating certain plant vulnerabilities to an insect. The spiroketal conophthorin is an important semiochemical produced by developing fungal spores. Spiroketals are also used as signals for scolytid communication. Plants and fungi are known to emit varying volatile profiles under biotic and abiotic stress. This paper reports distinctive temporal-volatile profiles from three abiotic treatments, room temperature (control), -15 °C (cold), and -15 °C to room temperature (shock), of cactus tissue plugs. Volatiles from the three treatments included monoterpenes from control plugs, compounds of varying classes and origin at later stages for cold plugs, and known semiochemicals, including spiroketals, at later stages for shock plugs. The results highlight several important findings: a unique tissue source of the spiroketals; abiotic cold-shock stress is indicated as the cause of spiroketal production; and, given previous findings of spirogenesis, fungal spore involvement is a probable biosynthetic origin of the spiroketals. These findings suggest an important role of fungal volatiles as signaling plant vulnerability to insects.

  9. Bacillus subtilis spore survival and expression of germination-induced bioluminescence after prolonged incubation under simulated Mars atmospheric pressure and composition: implications for planetary protection and lithopanspermia

    Science.gov (United States)

    Nicholson, Wayne L.; Schuerger, Andrew C.

    2005-01-01

    Bacterial endospores in the genus Bacillus are considered good models for studying interplanetary transfer of microbes by natural or human processes. Although spore survival during transfer itself has been the subject of considerable study, the fate of spores in extraterrestrial environments has received less attention. In this report we subjected spores of a strain of Bacillus subtilis, containing luciferase resulting from expression of an sspB-luxAB gene fusion, to simulated martian atmospheric pressure (7-18 mbar) and composition (100% CO(2)) for up to 19 days in a Mars simulation chamber. We report here that survival was similar between spores exposed to Earth conditions and spores exposed up to 19 days to simulated martian conditions. However, germination-induced bioluminescence was lower in spores exposed to simulated martian atmosphere, which suggests sublethal impairment of some endogenous spore germination processes.

  10. Arbuscular mycorrhizal fungi in chronically petroleum-contaminated soils in Mexico and the effects of petroleum hydrocarbons on spore germination.

    Science.gov (United States)

    Franco-Ramírez, Alicia; Ferrera-Cerrato, Ronald; Varela-Fregoso, Lucía; Pérez-Moreno, Jesús; Alarcón, Alejandro

    2007-10-01

    Arbuscular mycorrhizal fungi (AMF) have been hypothesized to enhance plant adaptation and growth in petroleum-contaminated soils. Nevertheless, neither AMF-biodiversity under chronically petroleum-contaminated soils nor spore germination response to petroleum hydrocarbons has been well studied. Chronically petroleum-contaminated rhizosphere soil and roots from Echinochloa polystachya, Citrus aurantifolia and C. aurantium were collected from Activo Cinco Presidentes, Tabasco, Mexico. Root colonization and spore abundance were evaluated. Additionally, rhizosphere soil samples were propagated using Sorghum vulgare L. as a plant trap under greenhouse conditions; subsequently, AMF-spores were identified. AMF-colonization ranged from 63 to 77% while spore number ranged from 715 to 912 in 100 g soil, suggesting that AMF tolerate the presence of petroleum hydrocarbons in the rhizosphere. From grass species, four AMF-morphospecies were identified: Glomus ambisporum, G. sinuosum (previously described as Sclerocystis sinuosum), Acaulospora laevis, and Ambispora gerdermanni. From citrus trees, four AMF-species were also identified: Scutellospora heterogama, G. ambisporum, Acaulospora scrobiculata, and G. citricola. In a second study, it was observed that spore germination and hyphal length of G. mosseae, G. ambisporum, and S. heterogama were significantly reduced by either volatile compounds of crude oil or increased concentrations of benzo[a ]pyrene or phenanthrene in water-agar.

  11. The ice nucleation ability of one of the most abundant types of fungal spores found in the atmosphere

    Directory of Open Access Journals (Sweden)

    R. Iannone

    2011-02-01

    Full Text Available Recent atmospheric measurements show that biological particles are a potentially important class of ice nuclei. Types of biological particles that may be good ice nuclei include bacteria, pollen and fungal spores. We studied the ice nucleation properties of water droplets containing fungal spores from the genus Cladosporium, one of the most abundant types of spores found in the atmosphere. For water droplets containing a Cladosporium spore surface area of ~217 μm2 (equivalent to ~5 spores with average diameters of 3.2 μm , 1% of the droplets froze by −28.5 °C and 10% froze by –30.1 °C. However, there was a strong dependence on freezing temperature with the spore surface area of Cladosporium within a given droplet. Mean freezing temperatures for droplets containing 1–5 spores are expected to be approximately −35.1 ± 2.3 °C (1σ S. D.. Atmospheric ice nucleation on spores of Cladosporium sp., or other spores with similar surface properties, thus do not appear to explain recent atmospheric measurements showing that biological particles participate as atmospheric ice nuclei. The poor ice nucleation ability of Cladosporium sp. may be attributed to the surface which is coated with hydrophobins (a class of hydrophobic proteins that appear to be widespread in filamentous fungi. Given the ubiquity of hydrophobins on spore surfaces, the current study may be applicable to many fungal species of atmospheric importance.

  12. Blue and red light-induced germination of resting spores in the red-tide diatom Leptocylindrus danicus.

    Science.gov (United States)

    Shikata, Tomoyuki; Iseki, Mineo; Matsunaga, Shigeru; Higashi, Sho-ichi; Kamei, Yasuhiro; Watanabe, Masakatsu

    2011-01-01

    Photophysiological and pharmacological approaches were used to examine light-induced germination of resting spores in the red-tide diatom Leptocylindrus danicus. The equal-quantum action spectrum for photogermination had peaks at about 440 nm (blue light) and 680 nm (red light), which matched the absorption spectrum of the resting spore chloroplast, as well as photosynthetic action spectra reported for other diatoms. DCMU, an inhibitor of photosynthetic electron flow near photosystem II, completely blocked photogermination. These results suggest that the photosynthetic system is involved in the photoreception process of light-induced germination. Results of pharmacological studies of the downstream signal transduction pathway suggested that Ca(2+) influx is the closest downstream neighbor, followed by steps involving calmodulin, nitric oxide synthase, guanylyl cyclase, protein-tyrosine-phosphatase, protein kinase C and actin polymerization and translation.

  13. Fungal endophytes in germinated seeds of the common bean, Phaseolus vulgaris

    Science.gov (United States)

    The common bean (Phaseolus vulgaris) is the most important food legume in the world, but its production is severely limited by several biotic and abiotic stressors. In search of a sustainable solution to this problem, we conducted a survey of fungal endophytes in 582 germinated seeds belonging to 11...

  14. Glycerol enhances fungal germination at the water-activity limit for life

    NARCIS (Netherlands)

    Stevenson, Andrew; Hamill, Philip G; Medina, Ángel; Kminek, Gerhard; Rummel, John D; Dijksterhuis, Jan; Timson, David J; Magan, Naresh; Leong, Su-Lin L; Hallsworth, John E

    2016-01-01

    For the most-extreme fungal xerophiles, metabolic activity and cell division typically halts between 0.700 and 0.640 water activity (approximately 70.0-64.0% relative humidity). Here, we investigate whether glycerol can enhance xerophile germination under acute water-activity regimes, using an

  15. HtrC is involved in proteolysis of YpeB during germination of Bacillus anthracis and Bacillus subtilis spores.

    Science.gov (United States)

    Bernhards, Casey B; Chen, Yan; Toutkoushian, Hannah; Popham, David L

    2015-01-01

    Bacterial endospores can remain dormant for decades yet can respond to nutrients, germinate, and resume growth within minutes. An essential step in the germination process is degradation of the spore cortex peptidoglycan wall, and the SleB protein in Bacillus species plays a key role in this process. Stable incorporation of SleB into the spore requires the YpeB protein, and some evidence suggests that the two proteins interact within the dormant spore. Early during germination, YpeB is proteolytically processed to a stable fragment. In this work, the primary sites of YpeB cleavage were identified in Bacillus anthracis, and it was shown that the stable products are comprised of the C-terminal domain of YpeB. Modification of the predominant YpeB cleavage sites reduced proteolysis, but cleavage at other sites still resulted in loss of full-length YpeB. A B. anthracis strain lacking the HtrC protease did not generate the same stable YpeB products. In B. anthracis and Bacillus subtilis htrC mutants, YpeB was partially stabilized during germination but was still degraded at a reduced rate by other, unidentified proteases. Purified HtrC cleaved YpeB to a fragment similar to that observed in vivo, and this cleavage was stimulated by Mn(2+) or Ca(2+) ions. A lack of HtrC did not stabilize YpeB or SleB during spore formation in the absence of the partner protein, indicating other proteases are involved in their degradation during sporulation.

  16. Effect of essential oils on Aspergillus spore germination, growth and mycotoxin production:a potential source of botanical food preservative

    Institute of Scientific and Technical Information of China (English)

    Negero Gemeda; Yimtubezinash Woldeamanuel; Daniel Asrat; Asfaw Debella

    2014-01-01

    Objective: To investigate effect of essential oils on Aspergillus spore germination, growth and mycotoxin production.Method: 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.Results: 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.Conclusions: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. Analysis of the predicting variables for daily and weekly fluctuations of two airborne fungal spores: Alternaria and Cladosporium

    Science.gov (United States)

    Recio, Marta; del Mar Trigo, María; Docampo, Silvia; Melgar, Marta; García-Sánchez, José; Bootello, Lourdes; Cabezudo, Baltasar

    2012-11-01

    Alternaria and Cladosporium are two fungal taxa whose spores (conidia) are included frequently in aerobiological studies of outdoor environments. Both spore types are present in the atmosphere of Malaga (Spain) throughout almost the entire year, although they reach their highest concentrations during spring and autumn. To establish predicting variables for daily and weekly fluctuations, Spearman's correlations and stepwise multiple regressions between spore concentrations (measured using a volumetric 7-day recorder) and meteorological variables were made with results obtained for both spore types in 1996 and 1997. Correlations and regressions were also made between the different taxa and their concentrations in different years. Significant and positive correlation coefficients were always obtained between spore concentrations of both taxa, followed by temperature, their concentrations in different years, sunshine hours and relative humidity (this last in a negative sense). For the two spore types we obtained higher correlation and regression coefficients using weekly data. We showed different regression models using weekly values. From the results and a practical point of view, it was concluded that weekly values of the atmospheric concentration of Alternaria spores can be predicted from the maximum temperature expected and its concentrations in the years sampled. As regards the atmospheric concentration of Cladoposrium spores, the weekly values can be predicted based on the concentration of Alternaria spores, thus saving the time and effort that would otherwise be employed in counting them by optical microscopy.

  18. Inhibition of fungal spore adhesion by zosteric Acid as the basis for a novel, nontoxic crop protection technology.

    Science.gov (United States)

    Stanley, Michele S; Callow, Maureen E; Perry, Ruth; Alberte, Randall S; Smith, Robert; Callow, James A

    2002-04-01

    ABSTRACT To explore the potential for nontoxic crop protection technologies based on the inhibition of fungal spore adhesion, we have tested the effect of synthetic zosteric acid (p-(sulfo-oxy) cinnamic acid), a naturally occurring phenolic acid in eelgrass (Zostera marina L.) plants, on spore adhesion and infection in two pathosystems: rice blast caused by Magnaporthe grisea and bean anthracnose caused by Colletotrichum lindemuthianum. We have shown that zosteric acid inhibits spore adhesion to model and host leaf surfaces and that any attached spores fail to develop appressoria, and consequently do not infect leaf cells. Low concentrations of zosteric acid that are effective in inhibiting adhesion are not toxic to either fungus or to the host. The inhibition of spore adhesion in the rice blast pathogen is fully reversible. On plants, zosteric acid reduced (rice) or delayed (bean) lesion development. These results suggest that there is potential for novel and environmentally benign crop protection technologies based on manipulating adhesion.

  19. Boric acid inhibits germination and colonization of Saprolegnia spores in vitro and in vivo.

    Science.gov (United States)

    Ali, Shimaa E; Thoen, Even; Evensen, Øystein; Skaar, Ida

    2014-01-01

    Saprolegnia infections cause severe economic losses among freshwater fish and their eggs. The banning of malachite green increased the demand for finding effective alternative treatments to control the disease. In the present study, we investigated the ability of boric acid to control saprolegniosis in salmon eggs and yolk sac fry. Under in vitro conditions, boric acid was able to decrease Saprolegnia spore activity and mycelial growth in all tested concentrations above 0.2 g/L, while complete inhibition of germination and growth was observed at a concentration of 0.8 g/L. In in vivo experiments using Atlantic salmon eyed eggs, saprolegniosis was controlled by boric acid at concentrations ranging from 0.2-1.4 g/L during continuous exposure, and at 1.0-4.0 g/L during intermittent exposure. The same effect was observed on salmon yolk sac fry exposed continuously to 0.5 g/L boric acid during the natural outbreak of saprolegniosis. During the experiments no negative impact with regard to hatchability and viability was observed in either eggs or fry, which indicate safety of use at all tested concentrations. The high hatchability and survival rates recorded following the in vivo testing suggest that boric acid is a candidate for prophylaxis and control of saprolegniosis.

  20. Lipid metabolism during bacterial growth, sporulation, and germination: kinetics of fatty acid and macromolecular synthesis during spore germination and outgrowth of Bacillus thuringiensis.

    Science.gov (United States)

    Nickerson, K W; De Pinto, J; Bulla, L A

    1975-01-01

    The timing and kinetics of fatty acid synthesis are delineated for Bacillus thuringiensis spore germination and outgrowth by analyzing [U-14C]acetate and [2-3H]glycerol incorporation into chloroform-methanol-extractable and trichloroacetic acid-precipitable lipids. In addition to measurement of pulsed and continuous labeling of fatty acids, monitoring the incorporation of radioactive phenylalanine, thymidine, and uridine from the onset of germination through first cell division provides a profile of biochemical activities related to membrane differentiation and cellular development. Upon germination, ribonucleic acid synthesis is initiated, immediately followed by rapid and extensive fatty acid synthesis that in turn precedes protein, deoxyribonucleic acid and triglyceride synthesis. Significantly, formation of fatty acids from acetate exhibits further developmental periodicity in which a large transient increase in fatty acid synthetic activity coincides with the approach of cell division. Radiorespirometric analyses indicates only slight oxidative decarboxylation of acetate and corroborates the extreme involvement of acetate in specific fatty acid biosynthetic reactions throughout cellular modification. These findings graphically demonstrate an intimate association of fatty acid metabolism with commitment to spore outgrowth and subsequent cell division.

  1. Regional-scale simulations of fungal spore aerosols using an emission parameterization adapted to local measurements of fluorescent biological aerosol particles

    Directory of Open Access Journals (Sweden)

    M. Hummel

    2014-04-01

    Full Text Available Fungal spores as a prominent type of primary biological aerosol particles (PBAP have been incorporated into the COSMO-ART regional atmospheric model, using and comparing three different emission parameterizations. Two literature-based emission rates derived from fungal spore colony counts and chemical tracer measurements were used as a parameterization baseline for this study. A third, new emission parameterization was adapted to field measurements of fluorescent biological aerosol particles (FBAP from four locations across Northern Europe. FBAP concentrations can be regarded as a lower estimate of total PBAP concentrations. Size distributions of FBAP often show a distinct mode at approx. 3 μm, corresponding to a diameter range characteristic for many fungal spores. Previous studies have suggested the majority of FBAP in several locations are dominated by fungal spores. Thus, we suggest that simulated fungal spore concentrations obtained from the emission parameterizations can be compared to the sum of total FBAP concentrations. A comparison reveals that parameterized estimates of fungal spore concentrations based on literature numbers underestimate measured FBAP concentrations. In agreement with measurement data, the model results show a diurnal cycle in simulated fungal spore concentrations, which may develop partially as a consequence of a varying boundary layer height between day and night. Measured FBAP and simulated fungal spore concentrations also correlate similarly with simulated temperature and humidity. These meteorological variables, together with leaf area index, were chosen to drive the new emission parameterization discussed here. Using the new emission parameterization on a model domain covering Western Europe, fungal spores in the lowest model layer comprise a fraction of 15% of the total aerosol mass over land and reach average number concentrations of 26 L−1. The results confirm that fungal spores and biological particles

  2. Impact of electromagnetic microwaves on the germination of spores of Streptomyces xanthochromogenes in a peat soil and in a liquid nutrient medium

    Science.gov (United States)

    Komarova, A. S.; Likhacheva, A. A.; Lapygina, E. V.; Maksimova, I. A.; Pozdnyakov, A. I.

    2010-01-01

    The impact of microwaves on the germination of spores of Streptomyces xanthochromogenes in a liquid nutrient medium and in a peat soil was studied. The treatment of inoculums with microwave radiation affected the development of the microorganisms from the stage of spore germination to the stage of the formation of microcolonies of actinomycetes upon the spore cultivation in the liquid medium. Typical hypnum-herbaceous peat was used to study the rate of germination of the actinomycetal spores in soil. The study of the dynamics of the Streptomyces xanthochromogenes population in the control soil (without treatment with microwaves) showed that the most active development of the culture took place in the soil moistened to 60% of the maximum water capacity. When the soil was moistened to the minimum adsorption capacity, the streptomyces did not complete their full cycle of development. The stimulation of the spore germination and mycelium growth with microwaves in the soil medium required a longer period in comparison with that for the liquid medium. The stimulation of the spore germination was observed in the liquid nutrient medium in the case of 30-s treatment and in the soil in the case of 60-s treatment.

  3. Spore germination, early development and some notes on the effects of in vitro culture medium on Frullania ericoides (Nees Mont. (Frullaniaceae, Marchantiophyta

    Directory of Open Access Journals (Sweden)

    Juliana da Costa Silva-e-Costa

    Full Text Available ABSTRACT In bryophytes, establishment can occur by a sexual or asexual process, but the production of spores enables colonization of a wider range of habitats and substrates than can asexual propagules. Successful germination is critical for establishment in a new environment. This paper addresses germination and sporeling development in Frullania ericoides, a leafy liverwort species. Fresh spores were inoculated in vitro in different culture strengths of Knop’s nutrient solution (one-fourth strength, half strength, full strength, one and a half strength and double strength, in order to evaluate the effects of this solution on spore germination and on the development of external protonema. On the first assessment, spore germination was observed at all the concentrations. Germination was endosporic, with cell division and proliferation, resulting in a globular protonema, within the spore wall. Beginning at the fourth week, the development of tightly concave primordial leaves was observed in all but the double-strength medium. Throughout the period of study, the treatments with lower concentrations exhibited external protonema with greater lengths. The double-strength treatment was statistically different from other treatments in at least two parameters. The results of this study demonstrate the potential of in vitro culture techniques for bryophyte spore studies and germplasm preservation.

  4. A Generic Method for Fungal Spore Detection: The use of a monoclonal antibody and surface plasmon resonance

    DEFF Research Database (Denmark)

    Skottrup, Peter Durand; Hearty, Stephen; Frøkiær, Hanne

    This study describes a biosensing principle for detection of fungal spores using surface plasmon resonance (SPR). The approach involves the use of a monoclonal antibody (mab) and a SPR sensor for label-free detection of the model organism Puccinia striiformis f.sp. tritici (Pst) a biotrophic fung...

  5. Germinação de esporos de Polypodium pleopeltifolium: resultados preliminares Polypodium pleopeltifolium spores germination: preliminary results

    Directory of Open Access Journals (Sweden)

    G. M. Felippe

    1992-07-01

    Full Text Available Polypodium pleopeltifolium é uma pteridófíta que ocorre, como epífita, em cerrados do Estado de São Paulo. A espécie é fotoblástica positiva, mas alguns esporos germinam no escuro. Tratamento com aplicações curtas a 40 e 5ºC e temperaturas alternadas não aumentou a germinação no escuro. IAA não afetou a germinação, mas a germinação sob luz branca foi inibida por GA3 e ABA. Choques curtos de luz vermelha promoveram a germinação.Polypodium pleopeltifolium is an epiphytic fern which occurs in cerrado vegetation of the State of São Paulo, Brazil. The species is light sensitive for germination but some spores germinate in the absence of light. Short treatments at 40 or 5ºC and alternating temperatures did not increase the germination in dark conditions. Germination was not affected by IAA but it was reduced by GA3, CEPA and ABA. Red light (short treatments promoted germination.

  6. Transcriptome analysis of Bacillus thuringiensis spore life, germination and cell outgrowth in a vegetable-based food model.

    Science.gov (United States)

    Bassi, Daniela; Colla, Francesca; Gazzola, Simona; Puglisi, Edoardo; Delledonne, Massimo; Cocconcelli, Pier Sandro

    2016-05-01

    Toxigenic species belonging to Bacillus cereus sensu lato, including Bacillus thuringiensis, cause foodborne outbreaks thanks to their capacity to survive as spores and to grow in food matrixes. The goal of this work was to assess by means of a genome-wide transcriptional assay, in the food isolate B. thuringiensis UC10070, the gene expression behind the process of spore germination and consequent outgrowth in a vegetable-based food model. Scanning electron microscopy and Energy Dispersive X-ray microanalysis were applied to select the key steps of B. thuringiensis UC10070 cell cycle to be analyzed with DNA-microarrays. At only 40 min from heat activation, germination started rapidly and in less than two hours spores transformed in active growing cells. A total of 1646 genes were found to be differentially expressed and modulated during the entire B. cereus life cycle in the food model, with most of the significant genes belonging to transport, transcriptional regulation and protein synthesis, cell wall and motility and DNA repair groups. Gene expression studies revealed that toxin-coding genes nheC, cytK and hblC were found to be expressed in vegetative cells growing in the food model.

  7. Gene activity during germination of spores of the fern, Onoclea sensibilis: RNA and protein synthesis and the role of stored mRNA

    Science.gov (United States)

    Raghavan, V.

    1991-01-01

    Pattern of 3H-uridine incorporation into RNA of spores of Onoclea sensibilis imbibed in complete darkness (non-germinating conditions) and induced to germinate in red light was followed by oligo-dT cellulose chromatography, gel electrophoresis coupled with fluorography and autoradiography. In dark-imbibed spores, RNA synthesis was initiated about 24 h after sowing, with most of the label accumulating in the high mol. wt. poly(A) -RNA fraction. There was no incorporation of the label into poly(A) +RNA until 48 h after sowing. In contrast, photo-induced spores began to synthesize all fractions of RNA within 12 h after sowing and by 24 h, incorporation of 3H-uridine into RNA of irradiated spores was nearly 70-fold higher than that into dark-imbibed spores. Protein synthesis, as monitored by 3H-arginine incorporation into the acid-insoluble fraction and by autoradiography, was initiated in spores within 1-2 h after sowing under both conditions. Autoradiographic experiments also showed that onset of protein synthesis in the cytoplasm of the germinating spore is independent of the transport of newly synthesized nuclear RNA. One-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis of 35S-methionine-labelled proteins revealed a good correspondence between proteins synthesized in a cell-free translation system directed by poly(A) +RNA of dormant spores and those synthesized in vivo by dark-imbibed and photo-induced spores. These results indicate that stored mRNAs of O. sensibilis spores are functionally competent and provide templates for the synthesis of proteins during dark-imbibition and germination.

  8. Soil fungal and bacterial biomass determined by epifluorescence microscopy and mycorrhizal spore density in different sugarcane managements

    Directory of Open Access Journals (Sweden)

    Adriana Pereira Aleixo

    2014-04-01

    Full Text Available Crop productivity and sustainability have often been related to soil organic matter and soil microbial biomass, especially because of their role in soil nutrient cycling. This study aimed at measuring fungal and bacterial biomass by epifluorescence microscopy and arbuscular mycorrhizal fungal (AMF spore density in sugarcane (Saccharum officinarum L. fields under different managements. We collected soil samples of sugarcane fields managed with or without burning, with or without mechanized harvest, with or without application of vinasse and from nearby riparian native forest. The soil samples were collected at 10cm depth and storage at 4°C until analysis. Fungal biomass varied from 25 to 37µg C g-1 dry soil and bacterial from 178 to 263µg C g-1 dry soil. The average fungal/bacterial ratio of fields was 0.14. The AMF spore density varied from 9 to 13 spores g-1 dry soil. The different sugarcane managements did not affect AMF spore density. In general, there were no significant changes of microbial biomass with crop management and riparian forest. However, the sum of fungal and bacterial biomass measured by epifluorescence microscopy (i.e. 208-301µg C g-1 dry soil was very close to values of total soil microbial biomass observed in other studies with traditional techniques (e.g. fumigation-extraction. Therefore, determination of fungal/bacterial ratios by epifluorescence microscopy, associated with other parameters, appears to be a promising methodology to understand microbial functionality and nutrient cycling under different soil and crop managements.

  9. Lipid metabolism during bacterial growth, sporulation, and germination: differential synthesis of individual branched- and normal-chain fatty acids during spore germination and outgrowth of Bacillus thuringiensis.

    Science.gov (United States)

    Nickerson, K W; Bulla, L A; Mounts, T L

    1975-12-01

    The biosynthesis of individual branched- and normal-chain fatty acids during Bacillus thuringiensis spore germination and outgrowth was studied by comparing pulsed and continuous labeling of these fatty acids with [U-14C]acetate. The relative specific activity of each fatty acid varies with time as the cell progresses through outgrowth. However, fatty acid synthesis does occur in two distinct phases. Upon germination, acetate is incorporated only into the iso-isomers i-C13, i-C14, and i-C16; no normal or anteiso synthesis occurs. Subsequent to T30, the full complement of branched- and normal-chain homologues is formed and there is a dramatic enhancement in the overall rate of fatty acid synthesis. Significantly, this rate increase coincides with a marked shift from the synthesis of short-chain to long-chain fatty acids. These findings illustrate a dichotomy in synthesis that may result from initial fatty acid formation by preexisting spore fatty acid biosynthetic enzymes in the absence of de novo protein synthesis. Elucidation of the timing and kinetics of individual fatty acid formation provides a biochemical profile of activities directly related to membrane differentiation and cellular development.

  10. A laboratory assessment of the Waveband Integrated Bioaerosol Sensor (WIBS-4) using individual samples of pollen and fungal spore material

    Science.gov (United States)

    Healy, David A.; O'Connor, David J.; Burke, Aoife M.; Sodeau, John R.

    2012-12-01

    A Bioaerosol sensing instrument referred to as WIBS-4, designed to continuously monitor ambient bioaerosols on-line, has been used to record a multiparameter “signature” from each of a number of Primary Biological Aerosol Particulate (PBAP) samples found in air. These signatures were obtained in a controlled laboratory environment and are based on the size, asymmetry (“shape”) and auto-fluorescence of the particles. Fifteen samples from two separate taxonomic ranks (kingdoms), Plantae (×8) and Fungi (×7) were individually introduced to the WIBS-4 for measurement along with two non-fluorescing chemical solids, common salt and chalk. Over 2000 individual-particle measurements were recorded for each sample type and the ability of the WIBS spectroscopic technique to distinguish between chemicals, pollen and fungal spore material was examined by identifying individual PBAP signatures. The results obtained show that WIBS-4 could potentially be a very useful analytical tool for distinguishing between natural airborne PBAP samples, such as the fungal spores and may potentially play an important role in detecting and discriminating the toxic fungal spore, Aspergillus fumigatus, from others in real-time. If the sizing range of the commercial instrument was customarily increased and permitted to operate simultaneously in its two sizing ranges, pollen and spores could potentially be discriminated between. The data also suggest that the gain setting sensitivity on the detector would also have to be reduced by a factor >5, to routinely detect, in-range fluorescence measurements for pollen samples.

  11. Seasonal Variation of Fungal Spores in Size-fractionated Ambient Particulate Matter in Beijing, China, Based on Molecular Tracer Measurements

    Science.gov (United States)

    Liang, L.; Engling, G.; He, K.

    2015-12-01

    Fungal aerosols were found to be the dominant fraction of biological aerosol components in the coarse mode in the atmosphere, influencing human health, the biosphere, atmospheric chemistry and climate. However, the total abundance of fungal spores in the atmosphere is rather uncertain and likely underestimated to a large extent by traditional Colony Forming Units (CFU) assays. Flow cytometry (FCM) was utilized in combination with fluorescent stains for the rapid counting of ambient fungal spores in this study. And, the sugar alcohols, mannitol and arabitol, proposed as molecular tracers for fungal aerosol were measured in PM2.5 and PM10 at an urban site in Beijing, China. The annual average concentrations of arabitol in PM2.5 and PM10 at the urban site were 7.4±9.4 ng m-3 and 21.0±20.4 ng m-3, and the respective mannitol concentrations were 10.3±9.5 ng m-3 and 31.9±26.9 ng m-3. Compared to PM2.5, the seasonal average concentrations of arabitol and mannitol in PM10 were varied more significantly. During summer and autumn higher arabitol and mannitol levels than during spring and winter were observed in coarse particles. Statistics analysis was further grouped into typical dry season (December 2010 to March 2011) and typical wet season (July 2011 to September 2011), revealed the different variation of fungal spores in different seasons. Moreover, the FCM results had significant positive correlation with the concentrations of the fungal tracers (R2 was 0.75 and 0.70 for arabitol and mannitol, respectively), supporting the utility of these sugar alcohols as effective fungal tracers.

  12. 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.

  13. The Effects of Some Pesticides on Spore Germination and Gametophyte Differentiation in Athyrium filix-femina (L. Roth. and Polypodium vulgare L.

    Directory of Open Access Journals (Sweden)

    Liliana Cristina SOARE

    2013-12-01

    Full Text Available The aim of this study was to assess the effects of a fungicide (copper hydroxide with 50% metallic copper (Co and of an insecticide (bifenthrin 100 g/l (B on spore germination and gametophyte development in the fern species Athyrium filix-femina (L. Schott. and Polypodium vulgare L. The experimental variants were: V1Co: 0.1 gr fungicide/100 ml Knop solution, V2Co: 0.2 gr fungicide/100 ml Knop solution, V3Co: 3 gr fungicide/100 ml Knop solution, V1B: 0.01 ml insecticide/100 ml Knop solution, V2B: 0.02 ml insecticide/100 ml Knop solution, V3B: 0.04 ml insecticide/100 ml Knop solution and Control (C: 100 ml Knop solution. Co inhibited spore germination in all the experimental variants tested on the species Athyrium filix-femina. In the V3Co variant, after 24 days, no spore germinated. B also inhibited spore germination in all the experimental variants. In Polypodium vulgare, Co significantly inhibited spore germination. In the experimental variants containing B, only in the V3B variant the germination is significantly inhibited. Calculations showed a significant negative correlation between the germination percentage and the concentration of pesticides. The fungicide also affected gametophyte differentiation, which happened much more slowly in both species. The rhizoids of the gametophytes of Polypodium vulgare showed modifications in their differentiation and morphology that could also be related to alterations in their biochemical composition. The experimental variants with the highest concentration of insecticide resulted in the differentiation of abnormal gametophytes growing in a tridimensional cellular mass with callus morphology. The responses of plants to the induced stress produced during the testing period may be used as biomarkers of environmental pollution caused by pesticides.

  14. Bacillus thermoamylovorans Spores with Very-High-Level Heat Resistance Germinate Poorly in Rich Medium despite the Presence of ger Clusters but Efficiently upon Exposure to Calcium-Dipicolinic Acid

    NARCIS (Netherlands)

    Berendsen, Erwin M; Krawczyk, Antonina O; Klaus, Verena; de Jong, Anne; Boekhorst, Jos; Eijlander, Robyn T; Kuipers, Oscar P; Wells-Bennik, Marjon H J

    2015-01-01

    High-level heat resistance of spores of Bacillus thermoamylovorans poses challenges to the food industry, as industrial sterilization processes may not inactivate such spores, resulting in food spoilage upon germination and outgrowth. In this study, the germination and heat resistance properties of

  15. Generation of the volatile spiroketals conophthorin and chalcogran by fungal spores on polyunsaturated fatty acids common to almonds and pistachios.

    Science.gov (United States)

    Beck, John J; Mahoney, Noreen E; Cook, Daniel; Gee, Wai S

    2012-12-05

    The spiroketal (E)-conophthorin has recently been reported as a semiochemical of the navel orangeworm moth, a major insect pest of California pistachios and almonds. Conophthorin and the isomeric spiroketal chalcogran are most commonly known as semiochemicals of several scolytid beetles. Conophthorin is both an insect- and plant-produced semiochemical widely recognized as a nonhost plant volatile from the bark of several angiosperm species. Chalcogran is the principal aggregation pheromone component of the six-spined spruce bark beetle. Recent research has shown conophthorin is produced by almonds undergoing hull-split, and both spiroketals are produced by mechanically damaged almonds. To better understand the origin of these spiroketals, the volatile emissions of orchard fungal spores on fatty acids common to both pistachios and almonds were evaluated. The volatile emission for the first 13 days of spores placed on a fatty acid was monitored. The spores investigated were Aspergillus flavus (atoxigenic), A. flavus (toxigenic), Aspergillus niger, Aspergillus parasiticus, Penicillium glabrum, and Rhizopus stolonifer. The fatty acids used as growth media were palmitic, oleic, linoleic, and linolenic. Spores on linoleic acid produced both spiroketals, those on linolenic acid produced only chalcogran, and those on palmitic and oleic acid did not produce either spiroketal. This is the first report of the spiroketals conophthorin and chalcogran from a fungal source.

  16. Absence of Fungal Spore Internalization by Bronchial Epithelium in Mouse Models Evidenced by a New Bioimaging Approach and Transmission Electronic Microscopy.

    Science.gov (United States)

    Rammaert, Blandine; Jouvion, Grégory; de Chaumont, Fabrice; Garcia-Hermoso, Dea; Szczepaniak, Claire; Renaudat, Charlotte; Olivo-Marin, Jean-Christophe; Chrétien, Fabrice; Dromer, Françoise; Bretagne, Stéphane

    2015-09-01

    Clinical data and experimental studies suggest that bronchial epithelium could serve as a portal of entry for invasive fungal infections. We therefore analyzed the interactions between molds and the bronchial/bronchiolar epithelium at the early steps after inhalation. We developed invasive aspergillosis (Aspergillus fumigatus) and mucormycosis (Lichtheimia corymbifera) murine models that mimic the main clinical risk factors for these infections. Histopathology studies were completed with a specific computer-assisted morphometric method to quantify bronchial and alveolar spores and with transmission electron microscopy. Morphometric analysis revealed a higher number of bronchial/bronchiolar spores for A. fumigatus than L. corymbifera. The bronchial/bronchiolar spores decreased between 1 and 18 hours after inoculation for both fungi, except in corticosteroid-treated mice infected with A. fumigatus, suggesting an effect of cortisone on bronchial spore clearance. No increase in the number of spores of any species was observed over time at the basal pole of the epithelium, suggesting the lack of transepithelial crossing. Transmission electron microscopy did not show spore internalization by bronchial epithelial cells. Instead, spores were phagocytized by mononuclear cells on the apical pole of epithelial cells. Early epithelial internalization of fungal spores in vivo cannot explain the bronchial/bronchiolar epithelium invasion observed in some invasive mold infections. The bioimaging approach provides a useful means to accurately enumerate and localize the fungal spores in the pulmonary tissues.

  17. Effect of Nanoencapsulated Vitamin B1 Derivative on Inhibition of Both Mycelial Growth and Spore Germination of Fusarium oxysporum f. sp. raphani

    Directory of Open Access Journals (Sweden)

    Hyeon Yong Lee

    2013-02-01

    Full Text Available Nanoencapsulation of thiamine dilauryl sulfate (TDS, a vitamin B1 derivative, was proved to effectively inhibit the spore germination of Fusarium oxysporum f. sp. raphani (F. oxysporum, as well as mycelial growth. The average diameter of nanoparticles was measured as 136 nm by being encapsulated with an edible encapsulant, lecithin, whose encapsulation efficiency was about 55% in containing 200 ppm of TDS concentration: the 100 ppm TDS nanoparticle solution showed a mycelial growth inhibition rate of 59%. These results were about similar or even better than the cases of treating 100 ppm of dazomet, a positive antifungal control (64%. Moreover, kinetic analysis of inhibiting spore germination were estimated as 6.6% reduction of spore germination rates after 24 h treatment, which were 3.3% similar to the case of treating 100 ppm of a positive control (dazomet for the same treatment time. It was also found that TDS itself could work as an antifungal agent by inhibiting both mycelial growth and spore germination, even though its efficacy was lower than those of nanoparticles. Nanoparticles especially played a more efficient role in limiting the spore germination, due to their easy penetration into hard cell membranes and long resident time on the surface of the spore shell walls. In this work, it was first demonstrated that the nanoparticle of TDS not a harmful chemical can control the growth of F. oxysporum by using a lower dosage than commercial herbicides, as well as the inhibiting mechanism of the TDS. However, field trials of the TDS nanoparticles encapsulated with lecithin should be further studied to be effectively used for field applications.

  18. Deposition rates of fungal spores in indoor environments, factors effecting them and comparison with non-biological aerosols

    Science.gov (United States)

    Kanaani, Hussein; Hargreaves, Megan; Ristovski, Zoran; Morawska, Lidia

    Particle deposition indoors is one of the most important factors that determine the effect of particle exposure on human health. While many studies have investigated the particle deposition of non-biological aerosols, few have investigated biological aerosols and even fewer have studied fungal spore deposition indoors. The purpose of this study was, for the first time, to investigate the deposition rates of fungal particles in a chamber of 20.4 m 3 simulating indoor environments by: (1) releasing fungal particles into the chamber, in sufficient concentrations so the particle deposition rates can be statistically analysed; (2) comparing the obtained deposition rates with non-bioaerosol particles of similar sizes, investigated under the same conditions; and (3) investigating the effects of ventilation on the particle deposition rates. The study was conducted for a wide size range of particle sizes (0.54-6.24 μm), at three different air exchange rates (0.009, 1.75 and 2.5 h -1). An Ultraviolet Aerodynamic Particle Sizer Spectrometer (UVAPS) was used to monitor the particle concentration decay rate. The study showed that the deposition rates of fungal spores ( Aspergillus niger and Penicillium species) and the other aerosols (canola oil and talcum powder) were similar, especially at very low air exchange rates (in the order of 0.009). Both the aerosol and the bioaerosol deposition rates were found to be a function of particle size. The results also showed increasing deposition rates with increasing ventilation rates, for all particles under investigation. These conclusions are important in understanding the dynamics of fungal spores in the air.

  19. 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.

  20. Nanoparticles Composed of Zn and ZnO Inhibit Peronospora tabacina Spore Germination in vitro and P. tabacina Infectivity on Tobacco Leaves

    Directory of Open Access Journals (Sweden)

    George Wagner

    2016-03-01

    Full Text Available Manufactured nanoparticles (NPs are increasingly being used for commercial purposes and certain NP types have been shown to have broad spectrum antibacterial activity. In contrast, their activities against fungi and fungi-like oomycetes are less studied. Here, we examined the potential of two types of commercially available Zn NPs (Zn NPs and ZnO NPs to inhibit spore germination and infectivity on tobacco leaves resulting from exposure to the fungi-like oomycete pathogen Peronospora tabacina (P. tabacina. Both types of NPs, as well as ZnCl2 and bulk ZnO control treatments, inhibited spore germination compared to a blank control. ZnO ENMs were shown to be a much more powerful suppressor of spore germination and infectivity than bulk ZnO. ZnO and Zn NPs significantly inhibited leaf infection at 8 and 10 mg·L−1, respectively. Both types of NPs were found to provide substantially higher concentration dependent inhibition of spore germination and infectivity than could be readily explained by the presence of dissolved Zn. These results suggest that both NP types have potential for use as economic, low-dose, potentially non-persistent anti-microbial agents against the oomycete P. tabacina.

  1. Inhibition of clostridium perfringens spore germination and outgrowth by buffered vinegar and lemon juice concentrate during chilling.....of ground turkey road containing minimal ingredients

    Science.gov (United States)

    Inhibition of Clostridium perfringens spore germination and outgrowth in ground turkey roast containing minimal ingredients (salt and sugar), by buffered vinegar (MoStatin V) and a blend (buffered) of lemon juice concentrate and vinegar (MoStatin LV) was evaluated. Ground turkey roast was formulat...

  2. Inhibition of Clostridium perfringens spore germination and outgrowth by lemon juice and vinegar product in reduced NaCl roast beef

    Science.gov (United States)

    Inhibition of Clostridium perfringens spore germination and outgrowth in reduced sodium roast beef by a blend of buffered lemon juice concentrate and vinegar (MoStatin LV) during abusive exponential cooling was evaluated. Roast beef containing salt (NaCl; 1, 1.5, or 2%, wt/wt), blend of sodium pyro-...

  3. A microfluidic device for real-time monitoring of Bacillus subtilis bacterial spores during germination based on non-specific physicochemical interactions on the nanoscale level.

    Science.gov (United States)

    Zabrocka, L; Langer, K; Michalski, A; Kocik, J; Langer, J J

    2015-01-07

    A microfluidic device for studies on the germination of bacterial spores (e.g. Bacillus subtilis) based on non-specific interactions on the nanoscale is presented. A decrease in the population of spores during germination followed by the appearance of transition forms and an increase in the number of vegetative cells can be registered directly and simultaneously by using the microfluidic device, which is equipped with a conductive polymer layer (polyaniline) in the form of a nano-network. The lab-on-a-chip-type device, operating in a continuous flow regime, allows monitoring of germination of bacterial spores and analysis of the process in detail. The procedure is fast and accurate enough for quantitative real-time monitoring of the main steps of germination, including final transformation of the spores into vegetative cells. All of this is done without the use of biomarkers or any bio-specific materials, such as enzymes, antibodies and aptamers, and is simply based on an analysis of physicochemical interactions on the nanoscale level.

  4. Fungal Sinusitis

    Science.gov (United States)

    ... Marketplace Find an ENT Doctor Near You Fungal Sinusitis Fungal Sinusitis Patient Health Information News media interested ... sinusitis results. There Are Four Types Of Fungal Sinusitis: Mycetoma Fungal Sinusitis produces clumps of spores, a " ...

  5. Fungal endophytes from seeds of invasive, non-native Phragmites australis and their potential role in germination and seedling growth

    Science.gov (United States)

    Shearin, Zackery R. C.; Filipek, Matthew; Desai, Rushvi; Bickford, Wesley A.; Kowalski, Kurt P.; Clay, Keith

    2017-01-01

    Background and aimsWe characterized fungal endophytes of seeds of invasive, non-native Phragmites from three sites in the Great Lakes region to determine if fungal symbiosis could contribute to invasiveness through their effects on seed germination and seedling growth.MethodsField-collected seeds were surface sterilized and plated on agar to culture endophytes for ITS sequencing. Prevalence of specific endophytes from germinated and non-germinated seeds, and from seedlings, was compared.ResultsOne-third of 740 seeds yielded endophyte isolates. Fifteen taxa were identified with Alternaria sp. representing 54% of all isolates followed by Phoma sp. (21%) and Penicillium corylophilum (12%). Overall germination of seeds producing an isolate (36%) was significantly higher than seeds not producing an isolate (20%). Penicillium in particular was strongly associated with increased germination of seeds from one site. Sixty-three isolates and 11 taxa were also obtained from 30 seedlings where Phoma, Penicillium and Alternaria respectively were most prevalent. There was a significant effect of isolating an endophyte from the seed on seedling growth.ConclusionsThese results suggest that many endophyte taxa are transmitted in seeds and can increase seed germination and seedling growth of invasive Phragmites. The role of fungal endophytes in host establishment, growth and invasiveness in nature requires further research.

  6. The interactive effect of phosphorus and nitrogen on "in vitro" spore germination of Glomus etunicatum Becker & Gerdemann, root growth and mycorrhizal colonization

    Directory of Open Access Journals (Sweden)

    Bressan Wellington

    2001-01-01

    Full Text Available The effects of P and N amendment and its interactions on spore germination, root growth and colonized root length by Glomus etunicatum Becker & Gerdemann (INVAM S329 was studied "in vitro" in RiT - DNA transformed roots of Anthylis vulneraria sub sp. Sampaiana (Kidney vetch. Three N media concentrations (5, 10 and 50 mg/l at P constant level (2 mg/l and three P media concentrations (2, 10 and 20 mg/l at N constant level (5 mg/l were utilized as a treatment. Bécard & Fortin medium was used as a basal medium for root growth and colonized root length, and water/agar (0.8% media was the control for spore germination. Spore germination of G. etunicatum at low P level was reduced by N addition in relation to the control media, and at low N level addition of P stimulated spore germination. Total root length was stimulated by N addtion at low P level, but no significant difference (p£0.05 was observed between 10 and 50 mg/l of N. P addition at low N level media also stimulated total root growth, and a significant difference (p£0.05 was observed among P concentrations. Colonized root length by G. etunicatum increased significantly (p£0.05 with P additions at low N levels. Under low P level no significant differences was found between 10 and 50 mg/l of N. These results demonstrate that the interaction between P and N affect differently spore germination, root growth and colonized root lenght.

  7. A rapid colorimetric assay for mold spore germination using XTT tetrazolium salt

    Science.gov (United States)

    Carol A. Clausen; Vina W. Yang

    2011-01-01

    Current laboratory test methods to measure efficacy of new mold inhibitors are time consuming, some require specialized test equipment and ratings are subjective. Rapid, simple quantitative assays to measure the efficacy of mold inhibitors are needed. A quantitative, colorimetric microassay was developed using XTT tetrazolium salt to metabolically assess mold spore...

  8. Annual distribution of allergenic fungal spores in atmospheric particulate matter in the Eastern Mediterranean; a comparative study between ergosterol and quantitative PCR analysis

    Directory of Open Access Journals (Sweden)

    N. Lang-Yona

    2012-03-01

    Full Text Available Airborne fungal spores are an important fraction of atmospheric particulate matter and are major causative agents of allergenic and infectious diseases. Predicting the variability and species of allergy-causing fungal spores requires detailed and reliable methods for identification and quantification. There are diverse methods for their detection in the atmosphere and in the indoor environments; yet, it is important to optimize suitable methods for characterization of fungal spores in atmospheric samples. In this study we sampled and characterized total and specific airborne fungal spores from PM10 samples collected in Rehovot, Israel over an entire year. The total fungal spore concentrations vary throughout the year although the species variability was nearly the same. Seasonal equivalent spore concentrations analyzed by real-time quantitative-PCR-based methods were fall > winter > spring > summer. Reported concentrations based on ergosterol analysis for the same samples were and fall > spring > winter > summer. Correlation between the two analytical methods was found only for the spring season. These poor associations may be due to the per-spore ergosterol variations that arise from both varying production rates, as well as molecular degradation of ergosterol. While conversion of genome copies to spore concentration is not yet straightforward, the potential for improving this conversion and the ability of qPCR to identify groups of fungi or specific species makes this method preferable for environmental spore quantification. Identifying tools for establishing the relation between the presence of species and the actual ability to induce allergies is still needed in order to predict the effect on human health.

  9. Annual distribution of allergenic fungal spores in atmospheric particulate matter in the eastern mediterranean; a comparative study between ergosterol and quantitative PCR analysis

    Directory of Open Access Journals (Sweden)

    N. Lang-Yona

    2011-10-01

    Full Text Available Airborne fungal spores are an important fraction of atmospheric particulate matter and are major causative agents of allergenic and infectious diseases. Predicting the variability and species of allergy-causing fungal spores requires detailed and reliable methods for identification and quantification. There are diverse methods for their detection in the atmosphere and in the indoor environments; yet, it is important to optimize suitable methods for characterization of fungal spores in atmospheric samples. In this study we sampled and characterized total and specific airborne fungal spores from PM10 samples collected in Rohovot, Israel over an entire year. The total fungal spore concentrations vary throughout the year although the species variability was nearly the same. Seasonal equivalent spore concentrations analyzed by real-time quantitative-PCR-based methods were fall > winter > spring > summer. Reported concentrations based on ergosterol analysis for the same samples were and fall > spring > winter > summer. Correlation between the two analytical methods was found only for the spring season. These poor associations may be due to the per-spore ergosterol variations that arise from both varying production rates, as well as molecular degradation of ergosterol. While conversion of genome copies to spore concentration is not yet straightforward, the potential for improving this conversion and the ability of qPCR to identify groups of fungi or specific species makes this method preferable for environmental spore quantification. Identifying tools for establishing the relation between the presence of species and the actual ability to induce allergies is still needed in order to predict the effect on human health.

  10. Annual distribution of allergenic fungal spores in atmospheric particulate matter in the Eastern Mediterranean; a comparative study between ergosterol and quantitative PCR analysis

    Science.gov (United States)

    Lang-Yona, N.; Dannemiller, K.; Yamamoto, N.; Burshtein, N.; Peccia, J.; Yarden, O.; Rudich, Y.

    2012-03-01

    Airborne fungal spores are an important fraction of atmospheric particulate matter and are major causative agents of allergenic and infectious diseases. Predicting the variability and species of allergy-causing fungal spores requires detailed and reliable methods for identification and quantification. There are diverse methods for their detection in the atmosphere and in the indoor environments; yet, it is important to optimize suitable methods for characterization of fungal spores in atmospheric samples. In this study we sampled and characterized total and specific airborne fungal spores from PM10 samples collected in Rehovot, Israel over an entire year. The total fungal spore concentrations vary throughout the year although the species variability was nearly the same. Seasonal equivalent spore concentrations analyzed by real-time quantitative-PCR-based methods were fall > winter > spring > summer. Reported concentrations based on ergosterol analysis for the same samples were and fall > spring > winter > summer. Correlation between the two analytical methods was found only for the spring season. These poor associations may be due to the per-spore ergosterol variations that arise from both varying production rates, as well as molecular degradation of ergosterol. While conversion of genome copies to spore concentration is not yet straightforward, the potential for improving this conversion and the ability of qPCR to identify groups of fungi or specific species makes this method preferable for environmental spore quantification. Identifying tools for establishing the relation between the presence of species and the actual ability to induce allergies is still needed in order to predict the effect on human health.

  11. Lipoprotein biosynthesis by prolipoprotein diacylglyceryl transferase is required for efficient spore germination and full virulence of Bacillus anthracis

    Science.gov (United States)

    Okugawa, Shu; Moayeri, Mahtab; Pomerantsev, Andrei P.; Sastalla, Inka; Crown, Devorah; Gupta, Pradeep K.; Leppla, Stephen H.

    2011-01-01

    Bacterial lipoproteins play a crucial role in virulence in some Gram-positive bacteria. However, the role of lipoprotein biosynthesis in Bacillus anthracis is unknown. We created a B. anthracis mutant strain altered in lipoproteins by deleting the lgt gene encoding the enzyme prolipoprotein diacylglyceryl transferase, which attaches the lipid anchor to prolipoproteins. 14C-palmitate labeling confirmed that the mutant strain lacked lipoproteins, and hydrocarbon partitioning showed it to have decreased surface hydrophobicity. The anthrax toxin proteins were secreted from the mutant strain at nearly the same levels as from the wild-type strain. The TLR2-dependent TNF-α response of macrophages to heat-killed lgt mutant bacteria was reduced. Spores of the lgt mutant germinated inefficiently in vitro and in mouse skin. As a result, in a murine subcutaneous infection model, lgt mutant spores had markedly attenuated virulence. In contrast, vegetative cells of the lgt mutant were as virulent as those of the wild-type strain. Thus, lipoprotein biosynthesis in B. anthracis is required for full virulence in a murine infection model. PMID:22103323

  12. Heater Choice, Dampness and Mould Growth in 26 New Zealand Homes: A Study of Propensity for Mould Growth Using Encapsulated Fungal Spores

    OpenAIRE

    2015-01-01

    The relationship between the use of unflued gas heaters (UGH, N = 14) and heat pump heaters (HP, N = 12) located in the living rooms, and mould growth on the living room and bedroom walls, of 26 New Zealand (NZ) occupied homes was investigated during winter. Two methods were employed to evaluate the potential of mould growth on walls: (i) measurement of daily hyphal growth rate using a fungal detector (encapsulated fungal spores); and (ii) estimation of fungal contamination based on a four l...

  13. Isolation and Identification of Air Borne Fungal Spores and Fragments in Buildings within Usmanu Danfodiyo University Sokoto, Nigeria

    Directory of Open Access Journals (Sweden)

    Shinkafi Sa’adatu Aliyu

    2014-07-01

    Full Text Available Abstract - Indoor air contains a complex mixture of microorganisms, microorganism fragments, and by products such as molds, bacteria, endotoxins, mycotoxins, and volatile microbial organic compounds. Airborne fungi and bacteria can be toxic, allergenic and/or infectious. A research was conducted to determine the number and types of airborne fungal spores in Buildings of Usmanu Danfodiyo University Sokoto, Nigeria. Five (5 areas were chosen within the University for the Survey, these were student Hostel, Staff Quarters, Botanical garden, Microbiology laboratory and city campus of Usmanu Danfodiyo University. . A total number of fifteen (15 petri dishes containing potato dextrose agar each were vertically placed in each sampler and exposed at end of each height and site for 10 and 20 minutes respectively.  A total of thirteen (13 different fungal specie were identified namely; Aspergillus niger, A. flavus, A fumigates, A. ustus, A. terreus, Fusarium solani, F. oxysporum, Alterneria altenata, Rhizopus oryzae,  R. stolonifer, Helminthosporum sp., Penicillum candidum and Absedia corymbifera. Aspergillus niger had the highest frequency of occurrence of (14.9%, Helminthosporus species had the least frequency of occurrence of (1.5%. Conclusively it was observed that the concentration of fungal spores was high in the upper surface than the ground level at the time of the survey.

  14. Feasibility of Wide-Area Decontamination of Bacillus anthracis Spores Using a Germination-Lysis Approach

    Science.gov (United States)

    2011-11-16

    PRES-  Gruinard Island 5% formaldehyde  Sverdlosk Release UNKNOWN: but washing, chloramines , soil disposal believed to have been used...4664)  Novel lytic proteins for B. anthracis—1) germination specific lytic enzymes and 2) endolysins for vegetative cells (Dr. Paul Jackson

  15. Roles of the Bacillus anthracis Spore Protein ExsK in Exosporium Maturation and Germination

    Science.gov (United States)

    2009-12-01

    Fritsch, and T. Maniatis . 1989. Molecular cloning : a laboratory manual, 2nd ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY. 37...on ExsFA/BxpB. In spores lacking the exosporium surface protein BclA, ExsK fails to mature into high- molecular -mass species observed in wild-type...the envi- ronment. To gain insight into the molecular basis of exosporium as- sembly and function, we studied a previously identified but otherwise

  16. Nisin is an effective inhibitor of Clostridium difficile vegetative cells and spore germination.

    Science.gov (United States)

    Le Lay, Christophe; Dridi, Larbi; Bergeron, Michel G; Ouellette, Marc; Fliss, Ismaı L

    2016-02-01

    Clostridium difficile is the most frequently identified enteric pathogen in patients with nosocomial antibiotic-associated diarrhoea and pseudomembranous colitis. Several clinically isolated C. difficile strains are resistant to antibiotics other than metronidazole and vancomycin. Recently, bacteriocins of lactic acid bacteria have been proposed as an alternative or complementary treatment. The aim of this study was to investigate the inhibitory effect of nisin, a bacteriocin produced by several strains of Lactococcus lactis, against clinical isolates of C. difficile. Nisin Z obtained from culture of L. lactis subsp. lactis biovar. diacetylactis was tested along with commercial nisin A. The effect of nisin A on C. difficile spores was also examined. Nisin A and Z both inhibited the growth of all C. difficile isolates, and MICs were estimated at 6.2 μg ml(-1) for nisin Z and 0.8 μg ml(-1) for nisin A. In addition, C. difficile spores were also susceptible to nisin A (25.6 μg ml(-1)), which reduced spore viability by 40-50%. These results suggested that nisin and hence nisin-producing Lactococcus strains could be used to treat C. difficile-associated diarrhoea.

  17. Infection of Tribolium castaneum with Bacillus thuringiensis: quantification of bacterial replication within cadavers, transmission via cannibalism, and inhibition of spore germination.

    Science.gov (United States)

    Milutinović, Barbara; Höfling, Christina; Futo, Momir; Scharsack, Jörn P; Kurtz, Joachim

    2015-12-01

    Reproduction within a host and transmission to the next host are crucial for the virulence and fitness of pathogens. Nevertheless, basic knowledge about such parameters is often missing from the literature, even for well-studied bacteria, such as Bacillus thuringiensis, an endospore-forming insect pathogen, which infects its hosts via the oral route. To characterize bacterial replication success, we made use of an experimental oral infection system for the red flour beetle Tribolium castaneum and developed a flow cytometric assay for the quantification of both spore ingestion by the individual beetle larvae and the resulting spore load after bacterial replication and resporulation within cadavers. On average, spore numbers increased 460-fold, showing that Bacillus thuringiensis grows and replicates successfully in insect cadavers. By inoculating cadaver-derived spores and spores from bacterial stock cultures into nutrient medium, we next investigated outgrowth characteristics of vegetative cells and found that cadaver-derived bacteria showed reduced growth compared to bacteria from the stock cultures. Interestingly, this reduced growth was a consequence of inhibited spore germination, probably originating from the host and resulting in reduced host mortality in subsequent infections by cadaver-derived spores. Nevertheless, we further showed that Bacillus thuringiensis transmission was possible via larval cannibalism when no other food was offered. These results contribute to our understanding of the ecology of Bacillus thuringiensis as an insect pathogen. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  18. Infection of Tribolium castaneum with Bacillus thuringiensis: Quantification of Bacterial Replication within Cadavers, Transmission via Cannibalism, and Inhibition of Spore Germination

    Science.gov (United States)

    Milutinović, Barbara; Höfling, Christina; Futo, Momir; Scharsack, Jörn P.

    2015-01-01

    Reproduction within a host and transmission to the next host are crucial for the virulence and fitness of pathogens. Nevertheless, basic knowledge about such parameters is often missing from the literature, even for well-studied bacteria, such as Bacillus thuringiensis, an endospore-forming insect pathogen, which infects its hosts via the oral route. To characterize bacterial replication success, we made use of an experimental oral infection system for the red flour beetle Tribolium castaneum and developed a flow cytometric assay for the quantification of both spore ingestion by the individual beetle larvae and the resulting spore load after bacterial replication and resporulation within cadavers. On average, spore numbers increased 460-fold, showing that Bacillus thuringiensis grows and replicates successfully in insect cadavers. By inoculating cadaver-derived spores and spores from bacterial stock cultures into nutrient medium, we next investigated outgrowth characteristics of vegetative cells and found that cadaver-derived bacteria showed reduced growth compared to bacteria from the stock cultures. Interestingly, this reduced growth was a consequence of inhibited spore germination, probably originating from the host and resulting in reduced host mortality in subsequent infections by cadaver-derived spores. Nevertheless, we further showed that Bacillus thuringiensis transmission was possible via larval cannibalism when no other food was offered. These results contribute to our understanding of the ecology of Bacillus thuringiensis as an insect pathogen. PMID:26386058

  19. Crystal structure of the PepSY-containing domain of the YpeB protein involved in germination of Bacillus spores

    OpenAIRE

    2015-01-01

    This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/prot.24868 The crystal structure of the C-terminal domain of the Bacillus megaterium YpeB protein has been solved by X-ray crystallography to 1.80 Å resolution. The full-length protein is essential in stabilising the SleB cortex lytic enzyme in Bacillus spores, and may have a role in regulating SleB activity during spore germination. The YpeB-C crystal structure comprises three t...

  20. Crystal structure of the PepSY-containing domain of the YpeB protein involved in germination of Bacillus spores

    OpenAIRE

    2015-01-01

    This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/prot.24868 The crystal structure of the C-terminal domain of the Bacillus megaterium YpeB protein has been solved by X-ray crystallography to 1.80 ? resolution. The full-length protein is essential in stabilising the SleB cortex lytic enzyme in Bacillus spores, and may have a role in regulating SleB activity during spore germination. The YpeB-C crystal structure comprises three t...

  1. Petroleum hydrocarbon contamination, plant identity and arbuscular mycorrhizal fungal (AMF) community determine assemblages of the AMF spore-associated microbes.

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2016-09-01

    The root-associated microbiome is a key determinant of pollutant degradation, soil nutrient availability and plant biomass productivity, but could not be examined in depth prior to recent advances in high-throughput sequencing. Arbuscular mycorrhizal fungi (AMF) form symbioses with the majority of vascular plants. They are known to enhance mineral uptake and promote plant growth and are postulated to influence the processes involved in phytoremediation. Amplicon sequencing approaches have previously shown that petroleum hydrocarbon pollutant (PHP) concentration strongly influences AMF community structure in in situ phytoremediation experiments. We examined how AMF communities and their spore-associated microbiomes were structured within the rhizosphere of three plant species growing spontaneously in three distinct waste decantation basins of a former petrochemical plant. Our results show that the AMF community was only affected by PHP concentrations, while the AMF-associated fungal and bacterial communities were significantly affected by both PHP concentrations and plant species identity. We also found that some AMF taxa were either positively or negatively correlated with some fungal and bacterial groups. Our results suggest that in addition to PHP concentrations and plant species identity, AMF community composition may also shape the community structure of bacteria and fungi associated with AMF spores. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  2. Fluorescent bioaerosol particle, molecular tracer, and fungal spore concentrations during dry and rainy periods in a semi-arid forest

    Science.gov (United States)

    Ila Gosselin, Marie; Rathnayake, Chathurika M.; Crawford, Ian; Pöhlker, Christopher; Fröhlich-Nowoisky, Janine; Schmer, Beatrice; Després, Viviane R.; Engling, Guenter; Gallagher, Martin; Stone, Elizabeth; Pöschl, Ulrich; Huffman, J. Alex

    2016-12-01

    Bioaerosols pose risks to human health and agriculture and may influence the evolution of mixed-phase clouds and the hydrological cycle on local and regional scales. The availability and reliability of methods and data on the abundance and properties of atmospheric bioaerosols, however, are rather limited. Here we analyze and compare data from different real-time ultraviolet laser/light-induced fluorescence (UV-LIF) instruments with results from a culture-based spore sampler and offline molecular tracers for airborne fungal spores in a semi-arid forest in the southern Rocky Mountains of Colorado. Commercial UV-APS (ultraviolet aerodynamic particle sizer) and WIBS-3 (wideband integrated bioaerosol sensor, version 3) instruments with different excitation and emission wavelengths were utilized to measure fluorescent aerosol particles (FAPs) during both dry weather conditions and periods heavily influenced by rain. Seven molecular tracers of bioaerosols were quantified by analysis of total suspended particle (TSP) high-volume filter samples using a high-performance anion-exchange chromatography system with pulsed amperometric detection (HPAEC-PAD). From the same measurement campaign, Huffman et al. (2013) previously reported dramatic increases in total and fluorescent particle concentrations during and immediately after rainfall and also showed a strong relationship between the concentrations of FAPs and ice nuclei (Huffman et al., 2013; Prenni et al., 2013). Here we investigate molecular tracers and show that during rainy periods the atmospheric concentrations of arabitol (35.2 ± 10.5 ng m-3) and mannitol (44.9 ± 13.8 ng m-3) were 3-4 times higher than during dry periods. During and after rain, the correlations between FAP and tracer mass concentrations were also significantly improved. Fungal spore number concentrations on the order of 104 m-3, accounting for 2-5 % of TSP mass during dry periods and 17-23 % during rainy periods, were obtained from scaling the

  3. DNA analysis of outdoor air reveals a high degree of fungal diversity, temporal variability, and genera not seen by spore morphology.

    Science.gov (United States)

    Pashley, Catherine H; Fairs, Abbie; Free, Robert C; Wardlaw, Andrew J

    2012-02-01

    Fungi are ubiquitous with many capable of causing disease by direct infection, toxicoses, or allergy. Fungal spores are present in outdoor air throughout the year, yet airborne diversity is poorly characterised. Airborne fungal spores are routinely counted by microscopy, enabling identification to genera at best. We generated traditional microscopic counts over a year, then used environmental sequencing techniques to assess and compare 3 d selected from the main fungal spore season. The days selected corresponded to one with a high quantity of spores unidentifiable by microscopy, and two representing dry and wet summer periods. Over 86 % of genera detected by sequencing were not routinely identifiable by microscopy. A high degree of temporal variability was detected, with the percentage of clones attributed to Basidiomycota or Ascomycota, and composition of genera within each phylum varying greatly between days. Throughout the year Basidiomycota spores were found at higher levels than Ascomycota, but levels fluctuated daily with Ascomycota comprising 11-84 % of total spores and Basidiomycota 7-81 %. No significant difference was found between the proportion of clones attributed to each morphological group detected by sequencing to that counted by microscopy (P = 0.477, 0.985, and 0.561). The majority of abundant genera detected by DNA analysis are not routinely identified by microscopy (>75 %). Of those, several are known human and plant pathogens, and may represent unrecognised aeroallergens.

  4. Effects of meteorological factors on the composition of selected fungal spores in the air.

    Science.gov (United States)

    Grinn-Gofroń, Agnieszka; Bosiacka, Beata

    The aim of the study was to determine functional relationships between composition of air spora and meteorological factors, using multivariate statistical technique: canonical correspondence analysis (CCA). Analyses were conducted for the data collected during the 4 year (2007-2010) and, in order to show the dynamics of such relationships, for each year separately. The CCA results indicated that all statistically significant variables accounted for 15.3 % of the total variance in the spore data in the 4 years. The largest amount of the total variance was explained in this period by the mean air temperature (9.2 %). The meteorological factors impacted spore composition differently in different years, when analysis was done for each year separately. The highest values of the total variance in the spore data, explained by the statistically significant variables, were found in 2010 (32.3 %), with the highest contribution of mean air temperature (23.8 %). In that year, the above-mentioned parameter had the lowest value in comparison to other years. Canonical correspondence analysis provides not only a comprehensive assessment of the impact of meteorological factors on specific spore combinations in the air, but also informative graphical presentations of the results, illustrating the correlation between the occurrence of particular spore taxa and meteorological variables.

  5. Crystal structure of the PepSY-containing domain of the YpeB protein involved in germination of bacillus spores.

    Science.gov (United States)

    Üstok, Fatma Işık; Chirgadze, Dimitri Y; Christie, Graham

    2015-10-01

    The crystal structure of the C-terminal domain of the Bacillus megaterium YpeB protein has been solved by X-ray crystallography to 1.80-Å resolution. The full-length protein is essential in stabilising the SleB cortex lytic enzyme in Bacillus spores, and may have a role in regulating SleB activity during spore germination. The YpeB-C crystal structure comprises three tandemly repeated PepSY domains, which are aligned to form an extended laterally compressed molecule. A predominantly positively charged region located in the second PepSY domain may provide a site for protein interactions that are important in stabilising SleB and YpeB within the spore.

  6. Inhibition of spore germination, growth, and toxin activity of clinically relevant C. difficile strains by gut microbiota derived secondary bile acids.

    Science.gov (United States)

    Thanissery, Rajani; Winston, Jenessa A; Theriot, Casey M

    2017-03-06

    The changing epidemiology of Clostridium difficile infection over the past decades presents a significant challenge in the management of C. difficile associated diseases. The gastrointestinal tract microbiota provides colonization resistance against C. difficile, and growing evidence suggests that gut microbial derived secondary bile acids (SBAs) play a role. We hypothesized that the C. difficile life cycle; spore germination and outgrowth, growth, and toxin production, of strains that vary by age and ribotype will differ in their sensitivity to SBAs. C. difficile strains R20291 and CD196 (ribotype 027), M68 and CF5 (017), 630 (012), BI9 (001) and M120 (078) were used to define taurocholate (TCA) mediated spore germination and outgrowth, growth, and toxin activity in the absence and presence of gut microbial derived SBAs (deoxycholate, isodeoxycholate, lithocholate, isolithocholate, ursodeoxycholate, ω-muricholate, and hyodeoxycholate) found in the human and mouse large intestine. C. difficile strains varied in their rates of germination, growth kinetics, and toxin activity without the addition of SBAs. C. difficile M120, a highly divergent strain, had robust germination, growth, but significantly lower toxin activity compared to other strains. Many SBAs were able to inhibit TCA mediated spore germination and outgrowth, growth, and toxin activity in a dose dependent manner, but the level of inhibition and resistance varied across all strains and ribotypes. This study illustrates how clinically relevant C. difficile strains can have different responses when exposed to SBAs present in the gastrointestinal tract.

  7. Germination of Bacillus anthracis spores:research advances%炭疽芽孢杆菌芽孢萌发研究进展

    Institute of Scientific and Technical Information of China (English)

    高志奇; 刘先凯; 王恒樑

    2014-01-01

    芽孢是炭疽芽孢杆菌为应对不适的外界环境而形成的一种生命形式,休眠期的芽孢可以通过萌发恢复生长成为繁殖体。萌发过程作为关键步骤,可以由营养萌发剂和一些非营养类物质或者在其他情况下触发。在萌发过程中,萌发剂通过与存在于芽孢内膜上的萌发剂受体结合来触发芽孢核内各种阳离子的释放以及芽孢核对水的吸收。在芽孢皮层的肽聚糖被酶水解后,芽孢核逐渐完全水合化,开始进行新陈代谢以及大分子的合成活动,逐渐成长为一个新的营养细胞。该文将从萌发受体、芽孢皮层水解酶功能等方面对炭疽菌芽孢萌发机制进行阐述。%A spore is another life cycle form of Bacillus anthracis for resisting starvation.When conditions are favorable for growth, the dormant spore will germinate,go through outgrowth, and are ultimately converted back into a growing cell. As the first step back to vegetative growth, germination could be induced by nutrients and a variety of non-nutrient agents. Nutrient germinants trigger cation release and water absorption by binding to receptors in the spore′s inner membrane.Then the spore′s peptidoglycan cortex is hydrolyzed and the spore core rehydrates, which allows the resumption of spore metabo-lism and macromolecular synthesis.This paper reviews the nutrient germinant receptor and cortex lytic enzymes in the spore germination process of B.anthracis.

  8. Carbon nanofibers suppress fungal inhibition of seed germination of maize (Zea mays) and barley (Hordeum vulgare L.) crop

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Anjali, E-mail: joshianjali1982@gmail.com; Sharma, Arti [Centre For Nanoscience and Nanotechnology, Panjab University, Chandigarh (India); Nayyar, Harsh [Department of Botany, Panjab University, Chandigarh (India); Verma, Gaurav [Dr. SS Bhatnagar University Institute of Chemical Engineering and Technology, Panjab University, Chandigarh (India); Dharamvir, Keya [Department of Physics, Panjab University, Chandigarh (India)

    2015-08-28

    Carbon nanofibers (CNFs) are one of allotropes of carbon, consists of graphene layers arrangement in the form of stacked cones or like a cup diameter in nanometer and several millimeters in length. Their extraordinary mechanical, chemical and electronic properties are due to their small size. CNFs have been successfully applied in field of medicine in variety of diagnostic methods. They proven to be an excellent system for drug delivery, tissue regeneration, biosensor etc. This research focuses the applications of CNFs in all fields of Agriculture. In the we treated some fungal disease seed of maize and barley using functionalised CNFs. We find that the tested seeds grow just as well as the healthy seeds whereas the untreated fungal disease seeds, by themselves show very poor germination and seedling growth. This simple experiment shows the extraordinary ability of Carbon nanofibers in carrying effectively inside the germinated seeds.

  9. Carbon nanofibers suppress fungal inhibition of seed germination of maize (Zea mays) and barley (Hordeum vulgare L.) crop

    Science.gov (United States)

    Joshi, Anjali; Sharma, Arti; Nayyar, Harsh; Verma, Gaurav; Dharamvir, Keya

    2015-08-01

    Carbon nanofibers (CNFs) are one of allotropes of carbon, consists of graphene layers arrangement in the form of stacked cones or like a cup diameter in nanometer and several millimeters in length. Their extraordinary mechanical, chemical and electronic properties are due to their small size. CNFs have been successfully applied in field of medicine in variety of diagnostic methods. They proven to be an excellent system for drug delivery, tissue regeneration, biosensor etc. This research focuses the applications of CNFs in all fields of Agriculture. In the we treated some fungal disease seed of maize and barley using functionalised CNFs. We find that the tested seeds grow just as well as the healthy seeds whereas the untreated fungal disease seeds, by themselves show very poor germination and seedling growth. This simple experiment shows the extraordinary ability of Carbon nanofibers in carrying effectively inside the germinated seeds.

  10. Selection of Infective Arbuscular Mycorrhizal Fungal Isolates for Field Inoculation

    Directory of Open Access Journals (Sweden)

    Elisa Pellegrino

    2010-09-01

    Full Text Available Arbuscular mycorrhizal (AM fungi play a key role in host plant growth and health, nutrient and water uptake, plant community diversity and dynamics. AM fungi differ in their symbiotic performance, which is the result of the interaction of two fungal characters, infectivity and efficiency. Infectivity is the ability of a fungal isolate to establish rapidly an extensive mycorrhizal symbiosis and is correlated with pre-symbiotic steps of fungal life cycle, such as spore germination and hyphal growth. Here, different AM fungal isolates were tested, with the aim of selecting infective endophytes for field inoculation. Greenhouse and microcosm experiments were performed in order to assess the ability of 12 AM fungal isolates to produce spores, colonize host roots and to perform initial steps of symbiosis establishment, such as spore germination and hyphal growth. AM fungal spore production and root colonization were significantly different among AM fungal isolates. Spore and sporocarp densities ranged from 0.8 to 7.4 and from 0.6 to 2.0 per gram of soil, respectively, whereas root colonization ranged from 2.9 to 72.2%. Percentage of spore or sporocarp germination ranged from 5.8 to 53.3% and hyphal length from 4.7 to 79.8 mm. The ordination analysis (Redundancy Analysis, RDA showed that environmental factors explained about 60% of the whole variance and their effect on fungal infectivity variables was significant (P = 0.002. The biplot clearly showed that variables which might be used to detect infective AM fungal isolates were hyphal length and root colonization. Such analysis may allow the detection of the best parameters to select efficient AM fungal isolates to be used in agriculture.

  11. Spore Resistance Properties.

    Science.gov (United States)

    Setlow, Peter

    2014-10-01

    Spores of various Bacillus and Clostridium species are among the most resistant life forms known. Since the spores of some species are causative agents of much food spoilage, food poisoning, and human disease, and the spores of Bacillus anthracis are a major bioweapon, there is much interest in the mechanisms of spore resistance and how these spores can be killed. This article will discuss the factors involved in spore resistance to agents such as wet and dry heat, desiccation, UV and γ-radiation, enzymes that hydrolyze bacterial cell walls, and a variety of toxic chemicals, including genotoxic agents, oxidizing agents, aldehydes, acid, and alkali. These resistance factors include the outer layers of the spore, such as the thick proteinaceous coat that detoxifies reactive chemicals; the relatively impermeable inner spore membrane that restricts access of toxic chemicals to the spore core containing the spore's DNA and most enzymes; the low water content and high level of dipicolinic acid in the spore core that protect core macromolecules from the effects of heat and desiccation; the saturation of spore DNA with a novel group of proteins that protect the DNA against heat, genotoxic chemicals, and radiation; and the repair of radiation damage to DNA when spores germinate and return to life. Despite their extreme resistance, spores can be killed, including by damage to DNA, crucial spore proteins, the spore's inner membrane, and one or more components of the spore germination apparatus.

  12. Inhibitory effects of nisin and potassium sorbate alone or in combination on vegetative cells growth and spore germination of Bacillus sporothermodurans in milk.

    Science.gov (United States)

    Aouadhi, Chedia; Mejri, Slah; Maaroufi, Abderrazak

    2015-04-01

    The inhibitory activities of nisin or/and potassium sorbate on spores and vegetative cells of Bacillus sporothermodurans LTIS27, which are known to be a contaminant of dairy products and to be extremely heat-resistant, were investigated. First, the tested concentrations of nisin or potassium sorbate inhibited vegetative cell growth; with the minimum inhibitory concentrations were 5 × 10(3) IU/ml and 2% (w/v), respectively. Then, the behaviour of vegetative cells and spores in presence of sub-lethal concentrations of nisin (50 UI/ml) or/and potassium sorbate (0.2%), in milk at 37 °C for 5 days, were evaluated. In the absence of inhibitors, strain grew and sporulated at the end of the exponential phase. Nisin (50 UI/ml) was able to inhibit spore outgrowth but didn't affect their germination. It induced an immediate and transitory reduction (1.6log(10) after 1 h and 2.8log(10) after 6 h of incubation) of vegetative cell growth which reappeared between 10 h and 24 h. Potassium sorbate (0.2%) had a durable bacteriostatic effect (1.1log(10) after 6 h), on vegetative cells, followed by a slower regrowth. It was able to inhibit both germination and outgrowth of spores. Association of nisin and potassium sorbate, at sub-lethal concentrations, showed a synergistic effect and resulted in a total inhibition of cells growth after 5 days. The results illustrate the efficacy of nisin and potassium sorbate in combination, and the commercial potential of applying such treatment to decontaminate any product that has a problem with persistence of bacterial spores.

  13. Effect of the cortex-lytic enzyme SleC from non-food-borne Clostridium perfringens on the germination properties of SleC-lacking spores of a food poisoning isolate.

    Science.gov (United States)

    Paredes-Sabja, Daniel; Sarker, Mahfuzur R

    2010-11-01

    The hallmark of bacterial spore germination is peptidoglycan cortex hydrolysis by cortex-lytic enzymes. In spores of Clostridium perfringens wild-type strain SM101, which causes food poisoning, the sole essential cortex-lytic enzyme SleC is activated by a unique serine protease CspB. Interestingly, the non-food-borne wild-type strain F4969 encodes a significantly divergent SleC variant (SleCF4969) and 3 serine proteases (CspA, CspB, and CspC). Consequently, in this study we evaluated the functional compatibility of SleCF4969 and SleCSM101 by complementing the germination phenotypes of SM101ΔsleC spores with sleCF4969. Our results show that although pro-SleCF4969 was processed into mature SleCF4969 in the SM101ΔsleC spores, it partially restored spore germination with nutrient medium, with a mixture of ʟ-asparagine and KCl, or with a 1:1 chelate of Ca2+ and dipicolinic acid. While the amount of dipicolinic acid released was lower, the amount of hexosamine-containing material released during germination of SM101ΔsleC(sleCF4969) spores was similar to the amount released during germination of SM101 wild-type spores. The viability of SM101ΔsleC(sleCF4969) spores was 8- and 3-fold lower than that of SM101 and F4969 spores, respectively. Together, these data indicate that the peptidoglycan cortex hydrolysis machinery in the food poisoning isolate SM101 is functionally divergent than that in the non-food-borne isolate F4969.

  14. Site-Directed Mutagenesis and Structural Studies Suggest that the Germination Protease, GPR, in Spores of Bacillus Species Is an Atypical Aspartic Acid Protease

    Science.gov (United States)

    Carroll, Thomas M.; Setlow, Peter

    2005-01-01

    Germination protease (GPR) initiates the degradation of small, acid-soluble spore proteins (SASP) during germination of spores of Bacillus and Clostridium species. The GPR amino acid sequence is not homologous to members of the major protease families, and previous work has not identified residues involved in GPR catalysis. The current work has focused on identifying catalytically essential amino acids by mutagenesis of Bacillus megaterium gpr. A residue was selected for alteration if it (i) was conserved among spore-forming bacteria, (ii) was a potential nucleophile, and (iii) had not been ruled out as inessential for catalysis. GPR variants were overexpressed in Escherichia coli, and the active form (P41) was assayed for activity against SASP and the zymogen form (P46) was assayed for the ability to autoprocess to P41. Variants inactive against SASP and unable to autoprocess were analyzed by circular dichroism spectroscopy and multiangle laser light scattering to determine whether the variant's inactivity was due to loss of secondary or quaternary structure, respectively. Variation of D127 and D193, but no other residues, resulted in inactive P46 and P41, while variants of each form were well structured and tetrameric, suggesting that D127 and D193 are essential for activity and autoprocessing. Mapping these two aspartate residues and a highly conserved lysine onto the B. megaterium P46 crystal structure revealed a striking similarity to the catalytic residues and propeptide lysine of aspartic acid proteases. These data indicate that GPR is an atypical aspartic acid protease. PMID:16199582

  15. Calcium requirement of phytochrome-mediated fern-spore germination: no direct phytochrome-calcium interaction in the phytochrome-initiated transduction chain

    Science.gov (United States)

    Scheuerlein, R.; Wayne, R.; Roux, S. J.

    1989-01-01

    Phytochrome-mediated germination of fern spores of Dryopteris paleacea Sw. was initiated by a saturating red-light (R) irradiation after 20 h of imbibition. For its realization external Ca2+ was required, with a threshold at a submicromolar concentration, and an optimum was reached around 10(-4) M. At concentrations > or = 10(-1) M only a reduced response was obtained, based probably on an unspecific osmotic or ionic effect. The germination response was inhibited by La3+, an antagonist of Ca2+. From these results it is concluded that Ca2+ influx from the medium into the spores may be an important event in phytochrome-mediated germination. In the absence of Ca2+ the R-stimulated system remained capable of responding to Ca2+, added as late as 40 h after R. Moreover, Ca2+ was effective even if added after the active form of phytochrome, Pfr, had been abolished by far-red (FR) 24 h after R. Thus, the primary effect of Pfr, that initiates the transduction chain, does not require calcium. "Coupling" of Pfr to subsequent dark reactions has been investigated by R-FR irradiations with various dark intervals. The resulting "escape kinetics" were characterized by a lag phase (6 h) and half-maximal escape from FR reversibility (19 h). These kinetics were not significantly changed by the presence or absence of calcium. Thus, direct interaction of Pfr and calcium is not a step in the transduction chain initiated by the active form of phytochrome.

  16. Extraction and analysis of fungal spore biomarkers in atmospheric bioaerosol by HPLC-MS-MS and GC-MS.

    Science.gov (United States)

    Buiarelli, Francesca; Canepari, Silvia; Di Filippo, Patrizia; Perrino, Cinzia; Pomata, Donatella; Riccardi, Carmela; Speziale, Roberto

    2013-02-15

    Airborne microorganisms, as bacteria and fungi, are ubiquitous components of the atmospheric aerosol particles. In this paper, we report a method for the simultaneous extraction, purification, separation, identification and quantification of ergosterol, mannitol and arabitol as biomarkers of fungal spores in bioaerosol particles. After sampling by a low volume sampler, filters were spiked with mannitol-(13)C and dehydrocholesterol as internal standards. Samples were then extracted by accelerated solvent extraction using pure ethanol. The extract was then passed through an amino cartridge and divided in two parts: the apolar fraction, released from the cartridge, was subjected to liquid liquid extraction (by n-hexane), while polar compounds, retained by the cartridge, were eluted by a mixture of methanol-water. The two fractions were joined and analyzed by HPLC equipped with two different columns in series, and coupled to a triple-quadrupole mass spectrometer with Atmospheric Pressure Chemical Ionization source. In addition, the same fractions were analyzed, after derivatization, by GC-MS. The results obtained by the two techniques were finally compared, showing good agreement between them. Last, the contents of the three biomarkers have been estimated in three atmospheric samples collected in a suburban/rural site and, using literature conversion factors, correlated to fungal biomass.

  17. Detection of viable fungal spores contaminant on documents and rapid control of the effectiveness of an ethylene oxide disinfection using ATP assay.

    Science.gov (United States)

    Rakotonirainy, Malalanirina S; Héraud, Cécile; Lavédrine, Bertrand

    2003-01-01

    Filamentous fungi are able to damage and even destroy archival and library materials. Nowadays the conventional method for detecting such micro-organisms is to put them in cultures but such methods are laborious and time-consuming. ATP methodology has been widely applied in other domains and its success on bacteria and yeast has been demonstrated. Several commercial reagent kits are available but they did not give satisfactory results on spores mould. We have elaborated new extraction strategies specific to fungi. A comparison of 42 extraction protocols of ATP from fungal spores was carried out. Extraction at 100 degrees C with DMSO 90% in a Tris-acetate-EDTA buffer proved to be the best method. The viability of cells is estimated by the determination of adenylate energy charge (EC). We applied our method successfully on well-known species such as Aspergillus flavus, A. niger, A. fumigatus, A. versicolor, Neosartorya fischeri, Eurotium chevalieri, Penicillium chrysogenum, Chaetomium globosum and Ulocladium spp. The results suggest that the ATP bioluminescence assay provides a sensitive and time-saving method for detecting viable fungal spores. The validity of the procedure was also tested on spores killed by steam and on spores treated with ethylene oxide. We showed that EC determination could be used for a rapid control of the effectiveness of a disinfection process performed with ethylene oxide.

  18. Ice nucleation properties of rust and bunt fungal spores and their transport to high altitudes, where they can cause heterogeneous freezing

    Science.gov (United States)

    Haga, D. I.; Iannone, R.; Wheeler, M. J.; Mason, R.; Polishchuk, E. A.; Fetch, T.; van der Kamp, B. J.; McKendry, I. G.; Bertram, A. K.

    2013-07-01

    Rust and bunt spores that act as ice nuclei (IN) could change the formation characteristics and properties of ice-containing clouds. In addition, ice nucleation on rust and bunt spores, followed by precipitation, may be an important removal mechanism of these spores from the atmosphere. Using an optical microscope, we studied the ice nucleation properties of spores from four rust species (Puccinia graminis, Puccinia triticina, Puccinia allii, and Endocronartium harknesssii) and two bunt species (Tilletia laevis and Tilletia tritici) immersed in water droplets. We show that the cumulative number of IN per spore is 5 × 10-3, 0.01, and 0.10 at temperatures of roughly -24°C, -25°C, and -28°C, respectively. Using a particle dispersion model, we also investigated if these rust and bunt spores will reach high altitudes in the atmosphere where they can cause heterogeneous freezing. Simulations suggest that after 3 days and during periods of high spore production, between 6 and 9% of 15 µm particles released over agricultural regions in Kansas (U.S.), North Dakota (U.S.), Saskatchewan (Canada), and Manitoba (Canada) can reach at least 6 km in altitude. An altitude of 6 km corresponds to a temperature of roughly -25°C for the sites chosen. The combined results suggest that (a) ice nucleation by these fungal spores could play a role in the removal of these particles from the atmosphere and (b) ice nucleation by these rust and bunt spores are unlikely to compete with mineral dust on a global and annual scale at an altitude of approximately 6 km.

  19. 天麻种子与小菇属真菌共生萌发的研究%SYMBIOTIC GERMINATION BETWEEN GASTRODIA ELATA AND FUNGAL SPECIES OF MYCENA

    Institute of Scientific and Technical Information of China (English)

    徐锦堂; 郭顺星; 范黎; 娜仁

    2001-01-01

    Four fungal species of Mycena were identificated from the strains isolated from the protocorm and roots of Orchidaceae species.M. osmundicola was isolated from the proocorm of G.elata, M. orchidicola, M.dendrobii and M. anoectochila respectively separated from the roots of Cymbidium sinense, Dendrobium candidum and Anoectochilus roxburghii. The symbiotic germination test beteen G. Elata seeds and the above fungal species demonstrated that these fungal species can stimulate the seed germination, which means the species of Mycena may be the key mycorrhizal fungi of G elata, because there were no reports about the other fungal species which stimulate G.elata seed germination. Besides G. elata, the above species of Mycena also distributed the roots of the other orchids.

  20. 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].

  1. 组培条件对金发藓Polytrichum commune(Bryopsida:Musci)孢子萌发的影响%Influences of in vitro Factors on Spore Germination of Polytrichum commune ( Bryopsida: Musci)

    Institute of Scientific and Technical Information of China (English)

    俞英; 郭水良

    2008-01-01

    在组培条件下探讨了培养基类型,蔗糖浓度,光照强度,温度和铅离子对金发藓孢子萌发的影响.结果表明:含有丰富营养成分的培养基有利于孢子的两极萌发,而含有低浓度营养成分的培养基则有利于孢子的萌发.在含有矿质离子的培养基中,光对孢子萌发没有影响.然而,在没有矿质离子的SM培养基中,光能显著地抑制孢子的萌发.在ω=0.5%的蔗糖浓度和20~30℃的温度范围内,孢子萌发率较高.随着铅浓度的升高,孢子萌发率显著降低.组培条件下金发藓孢子萌发所需的上述条件也符合其野外生长的环境特征.研究结果揭示了对金发藓孢子萌发起促进或抑制的环境因子,有助于在野外或组培条件下人为地培养金发藓.%In vitro experiments were conducted to test the effects of culture medium types, content of sucrose, light intensities, tem-peratures and Pb2+ concentration on spore germination of Polytrichum commune ( Polytrichaceae, Musci). Results show: the culture medium with rich nutrient promotes the bipolar germination rate of the spores, while those with low nutrient increase the spore germina-tion rate. Whether light is present or absent, the spore germination rates are similar on the media with minerals. However, the light significantly inhibits the germination of the spores on SM medium without minerals. In the media with 0. 5% sucrose under the tempera-tures from 20 ~ 30℃ J the spores germinated well. With the increase of the Pb2+ concentration in the medium, the spore germination rate decreases significandy. The response of the spores to the factors in virto are speculated from their habitat characteristics in the field. Our results preliminarily reveal the factors to facilitate or inhibit the spore germination, which is valuable for us to culture P.commune both in the field and in vitro conditions.

  2. Cooperative manganese (II) activation of 3-phosphoglycerate mutase of Bacillus megaterium: a biological pH-sensing mechanism in bacterial spore formation and germination.

    Science.gov (United States)

    Kuhn, N J; Setlow, B; Setlow, P; Cammack, R; Williams, R

    1995-06-20

    The conversion of 3-P-glycerate mutase of Bacillus megaterium from a catalytically inactive to an active form was markedly more effective with buffered Mn2+ than with just added Mn2+. The previously reported stimulation by threonine disappeared when buffered Mn2+ was used. Activation of mutase showed a sigmoid dependence on Mn2+ concentration when buffered with tetramethylenediamine tetraacetate. The curve obeyed Hill kinetics with a coefficient of 2.1 +/- 0.1. At 0.5 microM free Mn2+, buffered with trimethylenediamine tetraacetate, activation of mutase increased about 73-fold over the pH range 6.6 to 7.4. Plotted against [OH-], the activation showed a strongly sigmoid response with Hill coefficient of 3.5 +/- 0.1. When mutase activated at pH 6.4 and 0.5 microM free Mn2+ in the presence of substrate was transferred to a similar medium at pH 7.4, the rate of product accumulation increased 360-fold within a few minutes. The pH sensitivity conferred upon mutase by low [Mn2+] may account for its large activity decrease during sporulation, and later increase during spore germination, when spore pH, respectively, declines and rises by about 1 unit. These changes result in the accumulation, and later reutilization, of 3-P-glycerate reserves in the spore. Such a pH-sensing function of Mn2+ may have wider biological uses.

  3. Fungal spore concentrations in two haematopoietic stem cell transplantation (HSCT) units containing distinct air control systems.

    Science.gov (United States)

    Brun, C P; Miron, D; Silla, L M R; Pasqualotto, A C

    2013-04-01

    Invasive fungal diseases have emerged as important causes of morbidity and mortality in haematological patients. In this study air samples were collected in two haematopoietic stem cell transplantation (HSCT) units, in which distinct air-control systems were in place. In hospital 1 no high-efficiency particulate air (HEPA) filter was available whereas in hospital 2 HSCT rooms were equipped with HEPA filters, with positive air pressure in relation to the corridor. A total of 117 samples from rooms, toilets and corridors were obtained during December 2009 to January 2011, using a six-stage Andersen sampler. In both hospitals, the concentration of potentially pathogenic fungi in the air was reduced in patients' rooms compared to corridors (P < 0·0001). Despite the presence of a HEPA filter in hospital 2, rooms in both hospitals showed similar concentrations of potentially pathogenic fungi (P = 0·714). These findings may be explained by the implementation of additional protective measures in hospital 1, emphasizing the importance of such measures in protected environments.

  4. Visible fungi growth and dampness assessed using a questionnaire versus airborne fungi, (1→3-β-d-glucan and fungal spore concentrations in flats

    Directory of Open Access Journals (Sweden)

    Małgorzata Sowiak

    2015-02-01

    Full Text Available Introduction The study aimed at determination of the usefulness of the subjective assessment of selected signs of fungi growth in flats and microclimate parameters to indicate the actual air contamination with culturable fungi, (1→3-β-D-glucans and fungal spores. Material and methods This analysis covered 22 flats, the inhabitants of which declared in a questionnaire interview the presence of the developed mycelium on solid surfaces in the flat. Air samples for determination of the culturable fungi, (1→3-β-D-glucans and (viable and non-viable fungal spores concentrations indoor and outdoor the flats during the heating period were collected. During bioaerosol sampling microclimate parameters were measured. Predictive models for concentrations of the tested biological agents with regard to various ways to assess fungal contamination of air in a flat (on the basis of a questionnaire or a questionnaire and microclimate measurements were built. Results The arithmetic means of temperature, relative humidity, CO2 concentration and air flow velocity in the flats were respectively: 20.5°C, 53%, 1431.6 ppm and 0 m/s. The geometric mean concentrations of airborne fungi, (1→3-β-D-glucans and fungal spores in these premises amounted to 2.9×102 cfu/m3, 1.6 ng/m3 and 5.7×103 spores/m3, respectively. The subjective assessment of fungi growth signs and microclimate characteristics were moderately useful for evaluation of the actual airborne fungi and (1→3-β-D-glucan concentrations (maximum percent of explained variance (VE = 61% and 67%, respectively, and less useful in evaluation of the actual fungal spore concentrations (VE < 29%. In the case of fungi, higher usefulness was indicated of the questionnaire evaluation supported by microclimate measurements (VE = 61.2%, as compared to the evaluation only by means of a questionnaire (VE = 46.9%. Conclusions Subjective evaluation of fungi growth signs in flats, separately or combined with microclimate

  5. 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.

  6. Fungal host specificity is not a bottleneck for the germination of Pyroleae species (Ericaceae) in a Bavarian forest.

    Science.gov (United States)

    Hynson, Nicole A; Weiß, Michael; Preiss, Katja; Gebauer, Gerhard; Treseder, Kathleen K

    2013-03-01

    Plants that produce dust seeds can recruit fungi to meet their earliest requirements for carbon and other nutrients. This germination strategy, termed initial mycoheterotrophy, has been well investigated among the orchid family, but there are numerous other plant lineages that have independently evolved mycoheterotrophic germination strategies. One of these lineages is the tribe Pyroleae (Ericaceae). While the fungi associated with mature plants in Pyroleae have been fairly well documented, their mycobionts at the germination and seedling stages are largely unknown. Here, we use an in situ seed baiting experiment along with molecular fingerprinting techniques and phylogenetic tests to identify the fungi associated with seedlings of two Pyroleae species, Pyrola chlorantha and Orthilia secunda. Our results indicate that similar to adult plants, Pyroleae seedlings can associate with a suite of ectomycorrhizal fungi. Some seedlings harboured single mycobionts, while others may have been inhabited by multiple fungi. The dominant seedling mycobiont of both Pyroleae species was a fungus of unknown trophic status in the order Sebacinales. This taxon was also the only one shared among seedlings of both investigated Pyroleae species. We discuss these results juxtaposed to orchids and one additional Pyrola species in the context of ontogenetic shifts in fungal host specificity for mycoheterotrophic nutrition.

  7. Germination of fungal conidia after exposure to low concentration ozone atmospheres.

    Science.gov (United States)

    The germinability of conidia of Alternaria alternata, Aspergillus flavus, Aspergillus niger, Penicillium digitatum, Penicillium expansum, or Penicillium italicum was determined periodically during exposure for approximately 100 days to a humid atmosphere of air alone or air containing 150 ppb ozone ...

  8. Architecture and Assembly of the Bacillus subtilis Spore Coat

    Science.gov (United States)

    2014-09-26

    icandy contaminated with germinated spores and these germinat ed spores were removed by centrifugation in a one step HistodenzTM (Sigma, St. Louis...spore resistance but also because some coat proteins play significant roles in spore germination . However, much recent work on the spore coat has... germinating spores of various Bacillus [14,21 30] and Clostridium [3 1] species. H owever, this analysis has generally been conducted on wild type

  9. Impact of sorbic acid and other mild preservation stresses on germination and outgrowth of Bacillus cereus spores

    NARCIS (Netherlands)

    Melis, van C.C.J.

    2013-01-01

      Weak organic acids such as sorbic acid, lactate, and acetic acid are widely used by the food industry as preservatives to control growth of micro-organisms. With the current trend towards milder processing of food products, opportunities arise for spore-forming spoilage and pathogenic microo

  10. Fungal flora and aflatoxin contamination in Pakistani wheat kernels (Triticum aestivum L. and their attribution in seed germination

    Directory of Open Access Journals (Sweden)

    Muhammad Asif Asghar

    2016-07-01

    Full Text Available This study aimed to isolate fungal pathogens and to subsequently quantify aflatoxin (AF; B1 + B2 + G1 + G2 contamination in wheat crops grown in Pakistan. Accordingly, a total of 185 wheat samples were collected from different areas of Pakistan and numerous potent fungal pathogens were isolated. AF contamination attributed to the presence of intoxicating fungal pathogens and resulting metabolic activities were quantified using a high performance liquid chromatography-fluorescence detector coupled with postcolumn derivatization. Additionally, the effect of fungal pathogens on seed germination was also examined. The results obtained showed that 50% of tested wheat samples were found to be contaminated with a diverse range of fungal species. The rate of recurrence of fungal pathogens were Aspergillus 31%, Penicillium 9%, Fusarium 8%, Rhizopus 3%, and Alternaria 2%. The presence of Tilletia indica and Claviceps purpurea species was found to be inevident in all tested wheat samples. AFB1 contamination was detected in 48 (26.0% samples and AFB2 in 13 (7.0% samples. AFG1 and AFG2 were not found in any of the tested samples. The contamination range of AFB1 and AFB2 was 0.05–4.78 μg/kg and 0.02–0.48 μg/kg, respectively. The total amount of AFs (B1 + B2 found in 48 (26.0% samples had a mean level of 0.53 ± 0.40 μg/kg and a contamination range of 0.02–5.26 μg/kg. The overall results showed that in 137 (74.0% samples, AFs were not found within detectable limits. Furthermore, in 180 (97.2% samples, AF levels were found to be below the maximum tolerated levels (MTL recommended by the European Union (4 μg/kg. In five (2.7% samples, AF contamination was higher than the MTL of the European Union. However, these samples were fit for human consumption with reference to the MTL (20 μg/kg assigned by the USA (Food and Drug Administration and Food and Agriculture Organization and Pakistan (Pakistan Standards and Quality Control Authority

  11. CONTROL OF POSTHARVEST TOMATO ROT BY SPORE SUSPENSION AND ANTIFUNGAL METABOLITES OF TRICHODERMA HARZIANUM

    Directory of Open Access Journals (Sweden)

    Momein H. El-Katatny

    2012-06-01

    Full Text Available Rot of cherry tomato (Lycopersicon esculentum fruits caused by several fungal pathogens is a detrimental disease leading to substantial yield loses worldwide. Alternaria isolates were the most common fungal species isolated from healthy or rotten fruits. Trichoderma harzianum spore suspension and culture filtrate were tested for their antagonistic activity on controlling tomato fruit rot. T. harzianum isolates suppressed or interfered with the growth of different postharvest tomato fungal pathogens albeit at different degrees. Their culture filtrate inhibited pathogen spore germination possibly due to the released extracellular diffusible metabolite(s. Besides, aberrant morphology of conidia was observed with deformation of hyphal tips. Furthermore, the resulting mycelia appeared desiccated with coagulated protoplasm leading to complete collapse of protoplasm in presence of T. harzianum culture filtrate. Application of T. harzianum spores to tomato fruits decreased disease severity significantly with the most profound effect at higher spore concentrations (108 cells per ml. Similarly, culture filtrate of T. harzianum prevented pathogen spore germination on the surface of tomato fruits leading to decreased incidence of rot symptoms at high culture filtrate concentrations. This work provides strong evidence that T. harzianum is a competent antagonist and its spore suspension and culture filtrate can be used efficiently to control postharvest tomato rot.

  12. Spore coat architecture of Clostridium novyi NT spores.

    Science.gov (United States)

    Plomp, Marco; McCaffery, J Michael; Cheong, Ian; Huang, Xin; Bettegowda, Chetan; Kinzler, Kenneth W; Zhou, Shibin; Vogelstein, Bert; Malkin, Alexander J

    2007-09-01

    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. Toward this end, we have used both transmission electron microscopy and atomic force microscopy to determine the structure of both dormant and 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.

  13. Relationships between airborne fungal spore concentration of Cladosporium and the summer climate at two sites in Britain

    Science.gov (United States)

    Hollins, P. D.; Kettlewell, P. S.; Atkinson, M. D.; Stephenson, D. B.; Corden, J. M.; Millington, W. M.; Mullins, J.

    Cladosporium conidia have been shown to be important aeroallergens in many regions throughout the world, but annual spore concentrations vary considerably between years. Understanding these annual fluctuations may be of value in the clinical management of allergies. This study investigates the number of days in summer when spore concentration exceeds the allergenic threshold in relation to regional temperature and precipitation at two sites in England and Wales over 27 years. Results indicate that number of days in summer when the Cladosporium spores are above the allergenic concentration is positively correlated with regional temperature and negatively correlated with precipitation for both sites over the study period. Further analysis used a winter North Atlantic Oscillation index to explore the potential for long-range forecasting of the aeroallergen. For both spore measurement sites, a positive correlation exists between the winter North Atlantic Oscillation index and the number of days in summer above the allergenic threshold for Cladosporium spore concentration.

  14. Germin-like protein 2 gene promoter from rice is responsive to fungal pathogens in transgenic potato plants.

    Science.gov (United States)

    Munir, Faiza; Hayashi, Satomi; Batley, Jacqueline; Naqvi, Syed Muhammad Saqlan; Mahmood, Tariq

    2016-01-01

    Controlled transgene expression via a promoter is particularly triggered in response to pathogen infiltration. This is significant for eliciting disease-resistant features in crops through genetic engineering. The germins and germin-like proteins (GLPs) are known to be associated with plant and developmental stages. The 1107-bp Oryza sativa root GLP2 (OsRGLP2) gene promoter fused to a β-glucuronidase (GUS) reporter gene was transformed into potato plants through an Agrobacterium-mediated transformation. The OsRGLP2 promoter was activated in response to Fusarium solani (Mart.) Sacc. and Alternaria solani Sorauer. Quantitative real-time PCR results revealed 4-5-fold increase in promoter activity every 24 h following infection. There was a 15-fold increase in OsRGLP2 promoter activity after 72 h of F. solani (Mart.) Sacc. treatment and a 12-fold increase observed with A. solani Sorauer. Our results confirmed that the OsRGLP2 promoter activity was enhanced under fungal stress. Furthermore, a hyperaccumulation of H2O2 in transgenic plants is a clear signal for the involvement of OsRGLP2 promoter region in the activation of specific genes in the potato genome involved in H2O2-mediated defense response. The OsRGLP2 promoter evidently harbors copies of GT-I and Dof transcription factors (AAAG) that act in response to elicitors generated in the wake of pathogen infection.

  15. Analysis of Airborne Fungal Spores in Shanghai Southwestern Area%上海市西南部气传致敏真菌消长规律

    Institute of Scientific and Technical Information of China (English)

    杨辰宸; 陈晨杰; 王莲芸; 范月蕾; 刘阳; 何丽明; 程辰; 蒋潇; 贾蒙杨; 高萍; 徐佳

    2011-01-01

    Objective To investigate the species, amount and seasonal distribution of airbome fungi spores and the effect of meteorological factors on airborne fungal spores in Shanghai southwestern area. Methods Daily airborne fungi spores monituring was performed by Gravitional method, and meterological data was collected. Alternaria isolated and incubated in various temperatures. Results Airborne fungal spores existed in Shanghai southwestern area druing whole year. The number of daily fungal spores was mighest in May and June and louest in December, January and February. A total of 5 602 fungal spores were collected,Alternaria (number of spores and percentage respectively: 2 669, 47.6%) and Negrospora (1 439, 25.7%) ,Stemphylium (215, 3.8%), Fusarium (199, 3.6%) , Corynespora cassiicola (166, 3.0%) , Curvularia (132, 2.4%), Epicoccum (125, 2.2%), Cladosporium macrocarpum Preuss (122, 2.2%), Ceveospora (112, 2.0%), Helminthosporium halodes (110, 2.0%). The partial correlations were analysed between the number of fungal spores and meteorological factors, including temperature (partial correlation coefficient:0.388, P < 0.001) , weather condition (-0.152, P=0.006) , wind direction (0.102, P=0.063) , humidity (0.053, P= 0.337) and wind velocity (0.051, P= 0.352). The dominant fungi, Alternaria was isolated firstly and incubated under various temperatures the diameters of the colonies were: 12.5 mm (4℃), 14 mm (10℃), 31.5 mm (15℃), 43 mm (20℃), 63 mm (25℃), 63 mm (30℃), 33.5 mm (35℃), 3.5 mm (40℃)temperature was the main respectively. Conclusions Alternaria and Negrospora were the dominant fungal species in Shanghai southwestern area. Influential factor of airborne fungi spores was associated mainly with temperature. The optimal incubate temperature was between 25℃ to 30℃ for Alternaria. Besides of that weather shown a significant correlation with the number of airborne fungal spores.%目的 研究上海市全年大气真菌孢子的

  16. Anti-biotic Effect of Slightly Acidic Electrolyzed Water on Plant Bacterial / Fungal Pathogen

    OpenAIRE

    津野, 和宣; 中村, 悌一

    2012-01-01

    The anti-biotic effect of slightly acidic electrolyzed water on plant pathogen was determined. The spores of 4 kinds of fungal pathogen and 17 kinds of plant pathogenic bacteria were applied at different concentration.###Slightly acidic electrolyzed water showed strong growth inhibition in germination of fungi spores tested. In addition, by the treatment with slightly acidic electrolyzed water for 30 sec., all kinds of bacteria tested were inhibited to grow on the medium.###The anti-biotic ef...

  17. Small acid-soluble spore proteins of Clostridium acetobutylicum are able to protect DNA in vitro and are specifically cleaved by germination protease GPR and spore protease YyaC.

    Science.gov (United States)

    Wetzel, Daniela; Fischer, Ralf-Jörg

    2015-11-01

    Small acid-soluble proteins (SASPs) play an important role in protection of DNA in dormant bacterial endospores against damage by heat, UV radiation or enzymic degradation. In the genome of the strict anaerobe Clostridium acetobutylicum, five genes encoding SASPs have been annotated and here a further sixth candidate is suggested. The ssp genes are expressed in parallel dependent upon Spo0A, a master regulator of sporulation. Analysis of the transcription start points revealed a σG or a σF consensus promoter upstream of each ssp gene, confirming a forespore-specific gene expression. SASPs were termed SspA (Cac2365), SspB (Cac1522), SspD (Cac1620), SspF (Cac2372), SspH (Cac1663) and Tlp (Cac1487). Here it is shown that with the exception of Tlp, every purified recombinant SASP is able to bind DNA in vitro thereby protecting it against enzymic degradation by DNase I. Moreover, SspB and SspD were specifically cleaved by the two germination-specific proteases GPR (Cac1275) and YyaC (Cac2857), which were overexpressed in Escherichia coli and activated by an autocleavage reaction. Thus, for the first time to our knowledge, GPR-like activity and SASP specificity could be demonstrated for a YyaC-like protein. Collectively, the results assign SspA, SspB, SspD, SspF and SspH of C. acetobutylicum as members of α/β-type SASPs, whereas Tlp seems to be a non-DNA-binding spore protein of unknown function. In acetic acid-extracted proteins of dormant spores of C. acetobutylicum, SspA was identified almost exclusively, indicating its dominant biological role as a major α/β-type SASP in vivo.

  18. ANALYSIS OF FUNGAL SPORE MYCOTOXIN AND THE RELATIONSHIP BETWEEN SPORE SURFACE AREA AND MYCOTOXIN CONTENT UTILIZING A PROTEIN TRANSLATION INHIBITION ASSAY

    Science.gov (United States)

    Due to mounting evidence suggesting that biological contamination in the built environment may cause a myriad of adverse health effects, research aimed at understanding the potential exposure to fungal organisms and their metabolites is of utmost importance. To this end we utiliz...

  19. Heater Choice, Dampness and Mould Growth in 26 New Zealand Homes: A Study of Propensity for Mould Growth Using Encapsulated Fungal Spores

    Directory of Open Access Journals (Sweden)

    Mikael Boulic

    2015-02-01

    Full Text Available The relationship between the use of unflued gas heaters (UGH, N = 14 and heat pump heaters (HP, N = 12 located in the living rooms, and mould growth on the living room and bedroom walls, of 26 New Zealand (NZ occupied homes was investigated during winter. Two methods were employed to evaluate the potential of mould growth on walls: (i measurement of daily hyphal growth rate using a fungal detector (encapsulated fungal spores; and (ii estimation of fungal contamination based on a four level scale visual inspection. The average wall psychrometric conditions were significantly different between the two heater type groups, in both the living rooms and the bedrooms with the UGH user homes being colder and damper than HP user homes. The UGHs were found to be a significant additional source of moisture in the living rooms which dramatically increased the capacity for fungi to grow on wall surfaces. The average daily hyphal growth rates were 4 and 16 times higher in the living rooms and in the bedrooms of the UGH user homes, respectively. Results from both mould detection methods gave good agreement, showing that the use of a fungal detector was an efficient method to predict the potential of mould growth on the inside of the external walls in NZ homes.

  20. Ultraviolet germicidal irradiation inactivation of airborne fungal spores and bacteria in upper-room air and HVAC in-duct configurations

    Energy Technology Data Exchange (ETDEWEB)

    Kujundzic, E.; Hernandez, M. [Colorado Univ., Boulder, CO (United States). Dept. of Civil, Environmental and Architectural Engineering; Miller, S.L. [Colorado Univ., Boulder, CO (United States). Dept. of Mechanical Engineering

    2007-01-15

    This article presented an evaluation of the efficiency of ultraviolet germicidal irradiation (UVGI) for inactivating airborne fungal spores and bacterial vegetative cells under 3 configurations, namely intrinsic, upper-room air, and in-duct. Several experiments were conducted in a pilot-scale chamber fitted with 4 corner ultraviolet lamps that irradiated the entire chamber; a full-scale room fitted with a UVGI system that irradiated the top 30 cm of the room; and, the supply air duct of a heating ventilation and air-conditioning (HVAC) system. Fungal spores and vegetative cells of bacterium were aerosolized regularly such that their numbers and physiologic state were comparable both with and without the UVGI lamps operating. The article provided information on the materials and methods used including the experimental facilities (pilot-scale chamber, full-scale room, and in-duct UVGI system and ductwork) as well as the methods used for the three experimental studies. It also discussed the bioaerosol generation and sampling and quantification. These included culturing and direct microscopy. UV fluence rate was described. Last, the the results, discussion and conclusions from the studies were presented. It was shown that increasing the air stream velocity through the supply air duct reduces the residence time of bioaerosol being exposed to in-duct UVGI. 36 refs., 3 figs.

  1. Kinetics of Germination of Individual Bacillus Spores and its Heterogeneity Triggered by Lysozyme%溶菌酶触发的芽孢杆菌芽孢萌发及其异质性研究

    Institute of Scientific and Technical Information of China (English)

    王桂文; 张鹏飞; 王晓春; 陈欢君; Peter Setlow; Li Yongqing

    2016-01-01

    【目的】了解溶菌酶触发芽孢杆菌孢子萌发的异质性及其机制,为认识芽孢(Spore)萌发机制和杀灭芽孢提供参考。【方法】应用拉曼光谱和微分干涉差(DIC)显微镜成像技术高通量分析大量单个Bacillus subtilis (Bs)和B.megaterium (Bm)芽孢经溶菌酶触发的萌发动态。【结果】溶菌酶浓度和温度越高,芽孢萌发越快,孢内CaDPA开始快速释放时间(Tlag )、快速释放所需时间(ΔTrelease )和芽孢皮层水解所需时间(ΔTlys )越短;低于20℃,Bs芽孢萌发的ΔTrelease值是25℃时的4倍以上。SpoVA蛋白高表达菌株的ΔTrelease值和普通菌株基本相同,而缺少皮层水解酶的菌株ΔTrelease值高于普通菌株。95℃处理15 min的孢子,其Tlag、ΔTrelease和ΔTlys值是对照的2倍以上。Bs芽孢萌发的异质性明显,不仅表现在芽孢间,也表现在菌株间。Bm芽孢对溶菌酶更敏感,芽孢间的异质性显著低于Bs。【结论】溶菌酶触发的芽孢萌发在物种、菌株和单细胞层面都存在显著的异质性;溶菌酶浓度和温度对芽孢萌发有重大影响;皮层水解酶也可能参与溶菌酶触发的芽孢萌发进程。%Objective]The heterogeneous germination and its mechanism of Baillus spores trig-gered by lysozyme were studied in order to look insight into the mechanism of spore germina-tion in general and provide new knowledge of inactivating bacterial spores.[Methods]The ki-netic of germinations of multiple individual decoated spores of Bacillus subtilis (Bs)and B. megaterium (Bm)triggered by lysozyme were followed by Raman spectroscopy and differentail interference contrast (DIC)microscopy.[Results]Higher concentrations of lysozyme and tem-peratures significantly speeded the germination of Bs decaoted spores and reduced the time Tlag , at which spores began release of the great major-ity of spores’1∶1 chelate of Ca2+ with dipico-linic acid (Ca

  2. Spore sensitivity to sunlight and freezing can restrict dispersal in wood-decay fungi.

    Science.gov (United States)

    Norros, Veera; Karhu, Elina; Nordén, Jenni; Vähätalo, Anssi V; Ovaskainen, Otso

    2015-08-01

    Assessment of the costs and benefits of dispersal is central to understanding species' life-history strategies as well as explaining and predicting spatial population dynamics in the changing world. While mortality during active movement has received much attention, few have studied the costs of passive movement such as the airborne transport of fungal spores. Here, we examine the potential of extreme environmental conditions to cause dispersal mortality in wood-decay fungi. These fungi play a key role as decomposers and habitat creators in forest ecosystems and the populations of many species have declined due to habitat loss and fragmentation. We measured the effect of simulated solar radiation (including ultraviolet A and B) and freezing at -25°C on the spore germinability of 17 species. Both treatments but especially sunlight markedly reduced spore germinability in most species, and species with thin-walled spores were particularly light sensitive. Extrapolating the species' laboratory responses to natural irradiance conditions, we predict that sunlight is a relevant source of dispersal mortality at least at larger spatial scales. In addition, we found a positive effect of spore size on spore germinability, suggesting a trade-off between dispersal distance and establishment. We conclude that freezing and particularly sunlight can be important sources of dispersal mortality in wood-decay fungi which can make it difficult for some species to colonize isolated habitat patches and habitat edges.

  3. Fungal allergens.

    OpenAIRE

    1995-01-01

    Airborne fungal spores occur widely and often in far greater concentrations than pollen grains. Immunoglobulin E-specific antigens (allergens) on airborne fungal spores induce type I hypersensitivity (allergic) respiratory reactions in sensitized atopic subjects, causing rhinitis and/or asthma. The prevalence of respiratory allergy to fungi is imprecisely known but is estimated at 20 to 30% of atopic (allergy-predisposed) individuals or up to 6% of the general population. Diagnosis and immuno...

  4. Back-trajectories show export of airborne fungal spores (Ganoderma sp.) from forests to agricultural and urban areas in England

    Science.gov (United States)

    Sadyś, M.; Skjøth, C. A.; Kennedy, R.

    2014-02-01

    We propose here the hypothesis that all of United Kingdom (UK) is likely to be affected by Ganoderma sp. spores, an important plant pathogen. We suggest that the main sources of this pathogen, which acts as a bioaerosol, are the widely scattered woodlands in the country, although remote sources must not be neglected. The hypothesis is based on related studies on bioaerosols and supported by new observations from a non-forest site and model calculations to support our hypothesis.

  5. Suppression of spore germination and aflatoxin biosynthesis in Aspergillus parasiticus during and after exposure to high levels of phosphine.

    Science.gov (United States)

    Antonacci, L; Salvat, A E; Faifer, G C; Godoy, H M

    1999-01-01

    Agar cultures of toxigenic Aspergillus parasiticus NRRL 2999 were exposed to phosphine (PH3), in levels ranging from 0 to 2000 ppm (vol/vol). It was found that with PH3 concentrations of 400 ppm or higher the growth of the fungus was totally arrested. When PH3 was vented and the agar plates were exposed to open air, 100% of the initial CFU developed into fully grown colonies after PH3 levels below 300 ppm, but at higher PH3 concentrations only 50% of the colonies developed. The same strain of A. parasiticus was inoculated into high moisture corn under conditions highly favorable for aflatoxin production, and it was exposed to a range of PH3 levels. After exposure to 500 ppm PH3, both fungal growth and aflatoxin synthesis resumed shortly after elimination of the toxic gas, but after exposure to PH3 levels of 1000 ppm and higher, the physical appearance of the contaminated corn was remarkably changed, showing reduced mycelial growth and almost complete absence of green pigmentation. In addition, aflatoxin synthesis was totally absent for the remainder of the experiment (20 days). These results strongly suggest that exposure to PH3 levels of 1000 ppm or higher could bring about persistent metabolic changes in surviving Aspergillus organisms.

  6. Modelling the effect of sub(lethal) heat treatment of Bacillus subtilis spores on germination rate and outgrowth to exponentially growing vegetative cells

    NARCIS (Netherlands)

    Smelt, J.P.P.M.; Bos, A.P.; Kort, R.; Brul, S.

    2008-01-01

    Spores of Bacillus subtilis were subjected to relatively mild heat treatments in distilled water and properties of these spores were studied. These spores had lost all or part of their dipicolinic acid (DPA) depending on the severity of the heat treatment. Even after relatively mild heat treatments

  7. Fungicide resistance assays for fungal plant pathogens.

    Science.gov (United States)

    Secor, Gary A; Rivera, Viviana V

    2012-01-01

    Fungicide resistance assays are useful to determine if a fungal pathogen has developed resistance to a fungicide used to manage the disease it causes. Laboratory assays are used to determine loss of sensitivity, or resistance, to a fungicide and can explain fungicide failures and for developing successful fungicide recommendations in the field. Laboratory assays for fungicide resistance are conducted by measuring reductions in growth or spore germination of fungi in the presence of fungicide, or by molecular procedures. This chapter describes two techniques for measuring fungicide resistance, using the sugarbeet leaf spot fungus Cercospora beticola as a model for the protocol. Two procedures are described for fungicides from two different classes; growth reduction for triazole (sterol demethylation inhibitor; DMI) fungicides, and inhibition of spore germination for quinone outside inhibitor (QoI) fungicides.

  8. Preliminary Research on the Factors Affected Spore Germination of Phyllactinia guttata in Corylus heterophylla × C .avellana%大果榛子白粉病病菌孢子萌发影响因素研究初探

    Institute of Scientific and Technical Information of China (English)

    潘福民; 王欢; 张洪璐

    2015-01-01

    为了解大果榛子白粉病的发生规律,系统地研究了不同碳源、氮源、温度、光照、pH对大果榛子白粉病病菌无性孢子萌发的影响。结果表明:不同的碳、氮源处理中最适于大果榛子白粉病病菌无性孢子萌发的碳源为蔗糖,氮源为甘氨酸、硝酸铵;中性条件下适于孢子的萌发;孢子萌发适宜的温度为20℃;24 h全光照条件下更适宜孢子萌发。%In order to understand the occurrence regularity of Phyllactinia guttata in Corylus heterophylla × C . avellana of Jilin area ,the effect of different carbon resource ,nitrogen resource ,temperature ,light and pH on the asexual spores germination was researched systematically for Phyllactinia guttata in Corylus heterophylla × C .avellana .The results showed that the most suitable carbon for the germination of asexual spores was su‐crose ,the most suitable nitrogen resources was NH2 CH2 COOH and NH4 NO3 under pH neutral conditions with the 15~25℃ ,and full light conditions for 24 h was more suitable for spore germination .

  9. Lag time for germination of Penicillium chrysogenum conidia is induced by temperature shifts.

    Science.gov (United States)

    Kalai, Safaa; Bensoussan, Maurice; Dantigny, Philippe

    2014-09-01

    In the environment, fungal conidia are subject to transient conditions. In particular, temperature is varying according to day/night periods. All predictive models for germination assume that fungal spores can adapt instantaneously to changes of temperature. The only study that supports this assumption (Gougouli and Koutsoumanis, 2012, Modelling germination of fungal spores at constant and fluctuating temperature conditions. International Journal of Food Microbiology, 152: 153-161) was carried out on Penicillium expansum and Aspergillus niger conidia that, in most cases, already produced germ tubes. In contrast, the present study focuses on temperature shifts applied during the first stages of germination (i.e., before the apparition of the germ tubes). Firstly, germination times were determined in steady state conditions at 10, 15, 20 and 25 °C. Secondly, temperature shifts (e.g., up-shifts and down-shifts) were applied at 1/4, 1/2, and 3/4 of germination times, with 5, 10 and 15 °C magnitudes. Experiments were carried out in triplicate on Penicillium chrysogenum conidia on Potato Dextrose Agar medium according to a full factorial design. Statistical analysis of the results clearly demonstrated that the assumption of instantaneous adaptation of the conidia should be rejected. Temperature shifts during germination led to an induced lag time or an extended germination time as compared to the experiments conducted ay steady state. The induced lag time was maximized when the amplitude of the shift was equal to 10 °C. Interaction between the instant and the direction of the shift was highlighted. A negative lag time was observed for a 15 °C down-shift applied at 1/4 of the germination time. This result suggested that at optimal temperature the rate of germination decreased with time, and that the variation of this rate with time depended on temperature.

  10. Cortex Peptidoglycan Lytic Activity in Germinating Bacillus anthracis Spores▿

    OpenAIRE

    2008-01-01

    Bacterial endospore dormancy and resistance properties depend on the relative dehydration of the spore core, which is maintained by the spore membrane and its surrounding cortex peptidoglycan wall. During spore germination, the cortex peptidoglycan is rapidly hydrolyzed by lytic enzymes packaged into the dormant spore. The peptidoglycan structures in both dormant and germinating Bacillus anthracis Sterne spores were analyzed. The B. anthracis dormant spore peptidoglycan was similar to that fo...

  11. 不同培养基和蔗糖质量浓度对细叶小羽藓孢子萌发的影响%Haplocladium microphyllum spore germination with different culture mediums and sucrose concentrations

    Institute of Scientific and Technical Information of China (English)

    杭璐璐; 张楠; 季梦成

    2012-01-01

    将细叶小羽藓Haplocladium microphyllum孢子接种在Beneck,1/2MS (Murashige and Skoog),MS,Knop,改良Knop等5种培养基上,用pH酸度计将酸碱度调至pH 7.0.分别加入适量蔗糖,5种培养基各设置不同蔗糖质量浓度:40,30,20,10,0 g·L-1,定时镜检孢子的萌发情况.结果表明:当蔗糖质量浓度为0~30g·L-1时随蔗糖质量浓度升高孢子萌发率升高,蔗糖质量浓度为30 g·L-1时孢子萌发率最高,当蔗糖质量浓度超过40 g·L-1时,孢子萌发受抑制.在蔗糖质量浓度为30 g·L-1的培养基上培养7天后,MS培养基上袍子萌发率最高,高达95.93%;Knop培养基上孢子最终萌发率最低,仅为60%~75%.%Spores of Haplocladium microphyllum were inoculated on Benecke, 1/2MS (Murashige and Skoog), MS, Knop, and improved Beneck's culture mediums, and pH was adjusted to 7.0 with a pH meter. Sucrose at 40, 30, 20, 10, and 0 g-L"' was added, and germination of the spores was observed by microscope after 24 h. Results showed that for treatments from 0-30 g'L"1 sucrose concentration increased. Germination .of the spores was highest with 30 g o L' sucrose concentration and inhibited with 40 g o L*1. After 7 d, the spore ger mi nation rate was greatest with the MS medium at 30 g*L~' (at 95.93%) and least with the Knop medium (60%-75%). It indicates the spore germination of Haplocladium microphyllum need certain osmotic pressure, but it would be inhibited in high osmotic pressure caused by high sucrose concentration. [Ch, 6 fig. 14 ref.

  12. Effect of Microgravity on Spore Germinability, Mycelial Growth and Pathogenicity of Penicillium expansum%微重力对扩展青霉孢子萌发、菌丝生长和致病力的影响

    Institute of Scientific and Technical Information of China (English)

    刘嘉; 李博强; 秦国政; 田世平

    2008-01-01

    After being onto 22nd recoverable satellite of China for 18-day spaceflight under microgravity condition.the growth and pathogenicity of Penicillium expansum were investigated.Spore germination rate of the spaceflight pathogen was insignificantly lower than that of the ground control.After germination,germ tube elongation of spaceflight pathogen was slower,as well as mycelia growth.However,there was no significant difference according to independent-samples T-test.The consistent results were obtained in vivo.The spaceflight pathogen exhibited a little weaker pathogenicity in peach fruit.These findings suggested that the microgravity reduced the growth and pathogenicity of P.expansum.but the effect was not marked.

  13. Quantifying the effect of sorbic acid, heat and combination of both on germination and outgrowth of Bacillus subtilis spores at single cell resolution

    NARCIS (Netherlands)

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

    2015-01-01

    Bacillus subtilis spores are a problem for the food industry as they are able to survive preservation processes. The spores often reside in food products, where their inherent protection against various stress treatments causes food spoilage. Sorbic acid is widely used as a weak acid preservative in

  14. Molecular Kinetics of Reviving Bacterial Spores

    OpenAIRE

    2013-01-01

    Bacterial spores can remain dormant for years, yet they possess a remarkable potential to rapidly resume a vegetative life form. Here, we identified a distinct phase at the onset of spore outgrowth, designated the ripening period. This transition phase is exploited by the germinating spore for molecular reorganization toward elongation and subsequent cell division. We have previously shown that spores of different ages, kept under various temperatures, harbor dissimilar molecular reservoirs (...

  15. Spore Coat Architecture of Clostridium novyi NT Spores▿

    OpenAIRE

    Plomp, Marco; McCaffery, J. Michael; Cheong, Ian; Huang, Xin; Bettegowda, Chetan; Kinzler, Kenneth W.; Zhou, Shibin; Vogelstein, Bert; Malkin, Alexander J.

    2007-01-01

    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. Toward this end, we have used both transmission electron microscopy and atomic force microscopy to determine the structure of both dormant and germinating spores. We found th...

  16. 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.

  17. Spore-to-spore agar culture of the myxomycete Physarum globuliferum.

    Science.gov (United States)

    Liu, Pu; Wang, Qi; Li, Yu

    2010-02-01

    The ontogeny of the myxomycete Physarum globuliferum was observed on corn meal agar and hanging drop cultures without adding sterile oat flakes, bacteria or other microorganisms. Its complete life cycle including spore germination, myxamoebae, swarm cells, plasmodial development, and maturity of fructifications was demonstrated. Details of spore-to-spore development are described and illustrated.

  18. INCIDENCE AND CONTROL OF SEED - BORNE FUNGAL INFECTIONS ASSOCIATED WITH POST - GERMINATION MORTALITY IN SEEDLINGS OF Melia volkensii GURKE

    Directory of Open Access Journals (Sweden)

    Mulanda ES

    2013-09-01

    Full Text Available A laboratory study was carried out at the School of Biological Sciences, Chiromo Campus, University of Nairobi, for identification of seed- borne fungi that emerge during germination of M. volkensii seeds. The study sought to determine the incidence, pathological symptoms and effects of the fungi on post -germination survival of seedlings. Mature seeds collected from wild trees in three agro-climatic zones in semi arid eastern Kenya were scarified by nipping and slitting of the testa and divided into two groups. The treatment group received a single pulse pre-treatment consisting of a 30 minute soak in 1% (m/v Bavistin, while the control group was soaked in tap water. Aspergillus flavus and Rhizopus stolonifer infections emerged in the control group. A Mann - Whitney U test showed the control group as having significantly higher infections with both fungi (range of p values = 0.003 to 0.010 during and after germination than the fungicide-treated group. Post-germination seedling survival was also significantly enhanced by 31.66% in the treated group relative to the control (range of p values = 0.004 to 0.010. A single pre- treatment with the systemic fungicide Bavistin may be recommended for reduction of seedling mortality in M. volkensii during and after germination.

  19. Ultrastructure of spore development in Scutellospora heterogama.

    Science.gov (United States)

    Jeffries, Peter; Robinson-Boyer, Louisa; Rice, Paul; Newsam, Ray J; Dodd, John C

    2007-07-01

    The ultrastructural detail of spore development in Scutellospora heterogama is described. Although the main ontogenetic events are similar to those described from light microscopy, the complexity of wall layering is greater when examined at an ultrastructural level. The basic concept of a rigid spore wall enclosing two inner, flexible walls still holds true, but there are additional zones within these three walls distinguishable using electron microscopy, including an inner layer that is involved in the formation of the germination shield. The spore wall has three layers rather than the two reported previously. An outer, thin ornamented layer and an inner, thicker layer are both derived from the hyphal wall and present at all stages of development. These layers differentiate into the outer spore layer visible at the light microscope level. A third inner layer unique to the spore develops during spore swelling and rapidly expands before contracting back to form the second wall layer visible by light microscopy. The two inner flexible walls also are more complex than light microscopy suggests. The close association with the inner flexible walls with germination shield formation consolidates the preferred use of the term 'germinal walls' for these structures. A thin electron-dense layer separates the two germinal walls and is the region in which the germination shield forms. The inner germinal wall develops at least two sub-layers, one of which has an appearance similar to that of the expanding layer of the outer spore wall. An electron-dense layer is formed on the inner surface of the inner germinal wall as the germination shield develops, and this forms the wall surrounding the germination shield as well as the germination tube. At maturity, the outer germinal wall develops a thin, striate layer within its substructure.

  20. Activate to eradicate: inhibition of Clostridium difficile spore outgrowth by the synergistic effects of osmotic activation and nisin.

    Directory of Open Access Journals (Sweden)

    Michelle M Nerandzic

    Full Text Available BACKGROUND: Germination is the irreversible loss of spore-specific properties prior to outgrowth. Because germinating spores become more susceptible to killing by stressors, induction of germination has been proposed as a spore control strategy. However, this strategy is limited by superdormant spores that remain unaffected by germinants. Harsh chemicals and heat activation are effective for stimulating germination of superdormant spores but are impractical for use in a hospital setting, where Clostridium difficile spores present a challenge. Here, we tested whether osmotic activation solutes will provide a mild alternative for stimulation of superdormant C. difficile spores in the presence of germinants as previously demonstrated in several species of Bacillus. In addition, we tested the hypothesis that the limitations of superdormancy can be circumvented with a combined approach using nisin, a FDA-approved safe bacteriocin, to inhibit outgrowth of germinated spores and osmotic activation solutes to enhance outgrowth inhibition by stimulating superdormant spores. PRINCIPAL FINDINGS: Exposure to germination solution triggered ~1 log(10 colony forming units (CFU of spores to germinate, and heat activation increased the spores that germinated to >2.5 log(10CFU. Germinating spores, in contrast to dormant spores, became susceptible to inhibition by nisin. The presence of osmotic activation solutes did not stimulate germination of superdormant C. difficile spores exposed to germination solution. But, in the absence of germination solution, osmotic activation solutes enhanced nisin inhibition of superdormant spores to >3.5 log(10CFU. The synergistic effects of osmotic activation solutes and nisin were associated with loss of membrane integrity. CONCLUSIONS: These findings suggest that the synergistic effects of osmotic activation and nisin bypass the limitations of germination as a spore control strategy, and might be a novel method to safely and

  1. Influence of sporulation medium composition on transcription of ger operons and the germination response of spores of Bacillus cereus ATCC 14579

    NARCIS (Netherlands)

    Hornstra, L.M.; Vries, de Y.P.; Vos, de W.M.; Abee, T.

    2006-01-01

    Bacillus cereus ATCC 14579 endospores were produced in Y1 medium, a nutrient-rich, chemically defined sporulation medium, and in modified G medium, containing low amounts of nutrients. The average transcription level of the seven ger operons per cell was 3.5 times higher in Y1 medium, and the spores

  2. [Effect of the spatial and seasonal soil heterogeneity over arbuscular mycorrhizal fungal spore abundance in the semi-arid valley of Tehuacán-Cuicatlán, Mexico].

    Science.gov (United States)

    Camargo-Ricalde, Sara Lucía; Esperón-Rodríguez, Manuel

    2005-01-01

    Recent studies have shown that some species of Mimosa (Leguminosae-Mimosoideae) create resource islands (RI), rich in soil organic matter and nutrients, as well as in arbuscular mycorrhyzal fungal (AMF) spores, in the semi-arid Valley of Tehuacán-Cuicatlán. The relevance of this fact is that arid and semi-arid regions are characterized by low fertility soils and scarce precipitation, limiting plant species growth and development; this explains why the presence of AM fungi may be advantageous for mycorrhizal desert plants. Fluctuations in AMF spore numbers could be related to environmental, seasonal and soil factors which affect AMF sporulation, in addition to the life history of the host plant. The aim of this study was to asses the impact of spatial (resource islands vs open areas, OA) and seasonal (wet season vs start of dry season vs dry season) soil heterogeneity in the distribution and abundance of AMF spores in four different study sites within the Valley. We registered AMF spores in the 120 soil samples examined. Significant differences in the number of AMF spores were reported in the soil below the canopy of Mimosa species (RI) comparing with OA (RI > OA), and between Mimosa RI themselves when comparing along a soil gradient within the RI (soil near the trunk > soil below the middle of the canopy > soil in the margin of the canopy > OA); however, there were no significant differences between the soil closest to the trunk vs middle, and margin 's OA. Finally, more spores were reported in the soil collected during the wet season than during the dry season (wet > start of dry > dry). Therefore, the distribution of AMF spores is affected by spatial and seasonal soil heterogeneity. This study points out the relevance of Mimosa RI as AMF spore reservoirs and the potential importance of AM fungi for plant species survivorship and establishment in semi-arid regions. AM fungi have recently been recognized as an important factor determining plant species diversity

  3. Effect of fungal and plant metabolites on broomrapes (Orobanche and Phelipanche spp.) seed germination and radicle growth.

    Science.gov (United States)

    Cimmino, Alessio; Fernández-Aparicio, Mónica; Andolfi, Anna; Basso, Sara; Rubiales, Diego; Evidente, Antonio

    2014-10-29

    Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which cause heavy yield losses on important crops. The development of herbicides based on natural metabolites from microbial and plant origin, targeting early stages on parasitic plant development, might contribute to the reduction of broomrape seed bank in agricultural soils. Therefore, the effect of metabolites belonging to different classes of natural compounds on broomrape seed germination and radicle development was assayed in vitro. Among the metabolites tested, epi-sphaeropsidone, cyclopaldic acid, and those belonging to the sesquiterpene class induced broomrape germination in a species-specific manner. epi-Epoformin, sphaeropsidin A, and cytochalasans inhibited germination of GR24-treated broomrape seeds. The growth of broomrape radicle was strongly inhibited by sphaeropsidin A and compounds belonging to cyclohexene epoxide and cytochalasan classes. Broomrape radicles treated with epi-sphaeropsidone developed a layer of papillae while radicles treated with cytochalasans or with sphaeropsidin A turned necrotic. These findings allow new lead natural herbicides for the management of parasitic weeds to be identified.

  4. 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.

  5. Effects of Two Salts Compounds on Mycelial Growth, Sporulation, and Spore Germination of Six Isolates of Botrytis cinerea in the Western North of Algeria

    Directory of Open Access Journals (Sweden)

    Boualem Boumaaza

    2015-01-01

    Full Text Available Six isolates of Botrytis cinerea were isolated from leaves and stems of different tomato varieties taken from four areas in the northwest of Algeria where tomato is mostly grown in greenhouses and high tunnels. The purpose of this research was to determine the effect of two salts, NaCl and CaCl2, on three stages of Botrytis cinerea’s life cycle. All isolates tested were stimulated in 50 to 150 ppm; NaCl was the most effective treatment to increase mycelial growth at two tested concentrations. However, at 300 ppm concentration, CaCl2 completely inhibited the growth of mycelium; they reach 34.78% for the isolate TR46 and 26.72% for isolate F27. The sodium and calcium salts stimulated conidia production in liquid culture. We noticed that the effect of calcium chloride on sporulation was average while sodium chloride. In the medium containing 50 ppm, calcium chloride and sodium chloride increased the germination capacity of most isolates compared with the control. Other calcium salts, at 100 or 300 ppm, decreased the germination percentage of the conidia. With the exception of sodium salts, the inhibitions of germination reduce at 150 or 300 compared with the control. Conidial germination was slightly inhibited by sodium chloride only when the concentration was over 300 ppm.

  6. The crucial role of the Pls1 tetraspanin during ascospore germination in Podospora anserina provides an example of the convergent evolution of morphogenetic processes in fungal plant pathogens and saprobes.

    Science.gov (United States)

    Lambou, Karine; Malagnac, Fabienne; Barbisan, Crystel; Tharreau, Didier; Lebrun, Marc-Henri; Silar, Philippe

    2008-10-01

    Pls1 tetraspanins were shown for some pathogenic fungi to be essential for appressorium-mediated penetration into their host plants. We show here that Podospora anserina, a saprobic fungus lacking appressorium, contains PaPls1, a gene orthologous to known PLS1 genes. Inactivation of PaPls1 demonstrates that this gene is specifically required for the germination of ascospores in P. anserina. These ascospores are heavily melanized cells that germinate under inducing conditions through a specific pore. On the contrary, MgPLS1, which fully complements a DeltaPaPls1 ascospore germination defect, has no role in the germination of Magnaporthe grisea nonmelanized ascospores but is required for the formation of the penetration peg at the pore of its melanized appressorium. P. anserina mutants with mutation of PaNox2, which encodes the NADPH oxidase of the NOX2 family, display the same ascospore-specific germination defect as the DeltaPaPls1 mutant. Both mutant phenotypes are suppressed by the inhibition of melanin biosynthesis, suggesting that they are involved in the same cellular process required for the germination of P. anserina melanized ascospores. The analysis of the distribution of PLS1 and NOX2 genes in fungal genomes shows that they are either both present or both absent. These results indicate that the germination of P. anserina ascospores and the formation of the M. grisea appressorium penetration peg use the same molecular machinery that includes Pls1 and Nox2. This machinery is specifically required for the emergence of polarized hyphae from reinforced structures such as appressoria and ascospores. Its recurrent recruitment during fungal evolution may account for some of the morphogenetic convergence observed in fungi.

  7. Effects of temperature and light intensity on the release and germination of Ulva prolifera spores/gametes%温度与光照强度对浒苔孢子/配子放散和萌发的影响

    Institute of Scientific and Technical Information of China (English)

    韩红宾; 韦章良; 霍元子; 陈群芳; 张建恒; 何培民; 于克锋

    2015-01-01

    通过比较不同温度和光照强度对浒苔(Ulva prolifera)孢子/配子放散和萌发的影响,来探究适合浒苔孢子/配子放散和萌发的温度和光照强度。实验结果表明,适宜浒苔孢子/配子放散的温度和光照强度范围分别为20~30℃和180~300μmol·m-2·s-1。在温度25℃、光照强度240μmol·m-2·s-1时,浒苔孢子/配子的放散量最大。浒苔孢子/配子萌发的适宜温度和光照强度分别为15~25℃和40~160μmol·m-2·s-1,最适温度和光照强度分别为20℃和120μmol·m-2·s-1。本实验揭示了黄海绿潮优势种浒苔繁殖与生长的环境响应过程,为进一步探索黄海绿潮暴发机制提供理论依据。%Massive green tide has occurred every year in the coast of the Yellow Sea since 2007 ,seriously damaging the ecological environment and becoming a sustained marine environmental disaster.The dominant species of the floating green tide in the Yellow Sea was identified as U.prolifera.Floating thalli of Ulva prolifera samples were collected from Rudong coast,Jiangsu Province. Firstly,for the release of U.prolifera spores/gametes investigations,five temperature treatments (15,20, 25,30,35 ℃),five light intensity treatments(0,60,120,180,240,300 μmol·m-2 ·s-1 )and all materials were subjected to a 12L∶12D photoperiod throughout the experiment.In the second experiment,to study the response of the germination of U.prolifera spores/gametes to temperature and light intensity,six temperature treatments (10,15,20,25,30,35 ℃)under 60 μmol·m-2 ·s-1,six light intensity treatments (0,40,80,120,160,200μmol·m-2·s-1)under 20℃and all materials were subjected to a 12L∶12D photoperiod throughout the experiment. The results showed that the suitable temperature and light intensity for the release of U.prolifera spores/gametes were 20-30 ℃ and 180 -300 μmol·m-2 ·s-1 ,respectively.The maximum released amount of U.prolifera spores

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

    Science.gov (United States)

    2007-11-02

    Dendritic Cells Endocytose Bacillus anthracis Spores: Implications for Anthrax Pathogenesis1 Katherine C. Brittingham,* Gordon Ruthel,* Rekha G...germination and dissemination of spores. Found in high frequency throughout the respiratory track, dendritic cells (DCs) routinely take up foreign...COVERED - 4. TITLE AND SUBTITLE Dendritic cells endocytose Bacillus anthracis spores: implications for anthrax pathogenesis, The Journal of

  9. Selection of Streptomyces against soil borne fungal pathogens by a standardized dual culture assay and evaluation of their effects on seed germination and plant growth.

    Science.gov (United States)

    Kunova, Andrea; Bonaldi, Maria; Saracchi, Marco; Pizzatti, Cristina; Chen, Xiaoyulong; Cortesi, Paolo

    2016-11-09

    In the search for new natural resources for crop protection, streptomycetes are gaining interest in agriculture as plant growth promoting bacteria and/or biological control agents. Because of their peculiar life cycle, in which the production of secondary metabolites is synchronized with the development of aerial hyphae and sporulation, the commonly used methods to screen for bacterial antagonists need to be adapted. The dual culture assay was standardized in terms of inoculation timing of Streptomyces antagonist and pathogen, and growth rate of different fungal pathogens. In case of fast-growing fungi, inoculation of the antagonist 2 or 3 days prior to the pathogen resulted in significantly stronger inhibition of mycelium growth. One hundred and thirty Streptomyces strains were evaluated against six destructive soil borne pathogens. The activity of strains varied from broad-spectrum to highly specific inhibition of individual pathogens. All strains inhibited at least one tested pathogen. Three strains, which combined the largest broad-spectrum with the highest inhibition activity, were selected for further characterization with four vegetable species. All of them were able to colonize seed surface of all tested vegetable crops. They mostly improved radicle and hypocotyl growth in vitro, although no statistically significant enhancement of biomass weight was observed in vivo. Occasionally, transient negative effects on germination and plant growth were observed. The adapted dual culture assay allowed us to compare the inhibition of individual Streptomyces strains against six fungal soil borne pathogens. The best selected strains were able to colonize the four vegetable crops and have a potential to be developed into biocontrol products. Although they occasionally negatively influenced plant growth, these effects did not persist during the further development. Additional in vivo studies are needed to confirm their potential as biological control or plant growth

  10. Effects of meteorological conditions on spore plumes

    Science.gov (United States)

    Burch, M.; Levetin, E.

    2002-05-01

    Fungal spores are an ever-present component of the atmosphere, and have long been known to trigger asthma and hay fever symptoms in sensitive individuals. The atmosphere around Tulsa has been monitored for airborne spores and pollen with Burkard spore traps at several sampling stations. This study involved the examination of the hourly spore concentrations on days that had average daily concentrations near 50,000 spores/m3 or greater. Hourly concentrations of Cladosporium, Alternaria, Epicoccum, Curvularia, Pithomyces, Drechslera, smut spores, ascospores, basidiospores, other, and total spores were determined on 4 days at three sites and then correlated with hourly meteorological data including temperature, rainfall, wind speed, dew point, air pressure, and wind direction. On each of these days there was a spore plume, a phenomenon in which spore concentrations increased dramatically over a very short period of time. Spore plumes generally occurred near midday, and concentrations were seen to increase from lows around 20,000 total spores/m3 to highs over 170,000 total spores/m3 in 2 h. Multiple regression analysis of the data indicated that increases in temperature, dew point, and air pressure correlated with the increase in spore concentrations, but no single weather variable predicted the appearance of a spore plume. The proper combination of changes in these meteorological parameters that result in a spore plume may be due to the changing weather conditions associated with thunderstorms, as on 3 of the 4 days when spore plumes occurred there were thunderstorms later that evening. The occurrence of spore plumes may have clinical significance, because other studies have shown that sensitization to certain spore types can occur during exposure to high spore concentrations.

  11. Variaciones en la estacionalidad de polen y esporas fúngicas en la atmósfera de la ciudad de La Plata (Argentina Seasonal variation of pollen and fungal spores in the atmosphere of Plata city (Argentina

    Directory of Open Access Journals (Sweden)

    Daniela S Nitiu

    2011-12-01

    Full Text Available Se presentan los primeros datos sobre variaciones estacionales de polen y esporas fúngicas en su conjunto en la atmósfera de la ciudad de La Plata durante julio 2000 / junio 2001. El total de bioaerosoles fue de 201889.15 de los cuales el 15% correspondió a 54 tipos polínicos y el 85% a 79 tipos esporales. El Índice Polínico estuvo dado en un 74% por Polen Arbóreo (PA y en un 26% por Polen Herbáceo (PNA. La máxima concentración de PA tuvo lugar en septiembre con granos provenientes de Platanus y Fraxinus. El PNA presentó dos picos, el primero en diciembre procedente de Poaceae y el segundo en marzo debido a Ambrosia. Con respecto al componente fúngico, se identificaron esporas de Oomycota, Zygomycota, Myxomycota, Ascomycota y Basidiomycota. Estos bioaerosoles estuvieron presentes durante todo el año y en altas concentraciones siendo más abundantes en verano - otoño Las mitosporas de Hongos Imperfectos dominan la nube superando el 44% del total del Índice Esporal. El máximo aporte se registró en febrero dado por las esporas de Cladosporium. Se identificaron dos períodos estacionales en los cuales se hallan simultáneamente altas concentraciones de polen y esporas fúngicas. El primero se desarrolla en primavera y está integrado por Platanus, Fraxinus y Aspergillus / Penicillium y el segundo es estival e involucra a Ambrosia, Alternaria y Cladosporium.We present the first data on representativeness and seasonal variation of pollen and fungal spores as a whole in the atmosphere of the city of La Plata during july 2000 / june 2001. Total was 201889.15 bioaerosols, 15% of which was contributed by 54 pollen types and 85% by 79 spore types. The Pollinic Index came from arboreal pollen (PA in 74% and herbaceous pollen (PNA in 26%. The PA maximum concentration took place in september due to Platanus and Fraxinus. The PNA presented two peaks, one in december due to Poaceae, and the other one in march from Ambrosia. In regard to the

  12. Effects of eco-environmental factors on the production and distribution of arbuscular mycorrhizal fungal spores%生态环境因子对AM真菌孢子形成与分布的作用机制

    Institute of Scientific and Technical Information of China (English)

    孙向伟; 王晓娟; 陈牧; 豆存艳; 高飞翔; 金樑

    2011-01-01

    The number of spores in soil is an important indicator of the formation and distribution of arbuscular mycorrhizal (AM) fungi. The distribution of spores is mainly affected by climatic factors, soil properties, herbivores, host plants, and farming systems. Climatic factors and seasonal dynamics are the two main factors which determine the generation and distribution of AM fungal spores, including the infection, sporulation, and distribution of AM fungi by direct effects on the fungi or indirect effects through the host plants. Soil is the natural medium for spores. The distribution of spores in the soil ecosystem is mainly influenced by soil type, pH, soil moisture, permeability, nutrient content, and soil microorganisms. Host plants, herbivores, and farming measures also have an important impact on the AM fungal community. On the basis of the above, the influence of the intra- and inter-relationship of ecological factors on AM fungal spores distribution, and perspectives on the dynamics of communities in mycorrhizal ecology are discussed.%在自然土壤生态系统中,丛枝菌根(AM)真菌孢子的数量与菌根共生体的形成和分布具有密切的相关性,关注AM真菌孢子的形成与分布机制对于揭示菌根共生体的生态学功能具有重要意义.其中,探究外界环境因子对抱子分布的影响已经成为当前菌根生态学研究的热点问题之一.研究表明,影响抱子形成和分布的因素主要包括气候因子、土壤理化因子、草食动物、宿主植物种类以及耕作制度等.气候因子和季节动态是决定AM真菌孢子形成和分布的主要因子,它通过对AM真菌的直接作用,或者是通过对宿主植物的间接作用影响AM真菌的侵染、产孢和分布;土壤是抱子的天然培养基,土壤理化性状影响孢子分布的要素主要有土壤类型,pH值、土壤湿度、通透性、营养元素含量以及土壤微生物等;宿主植物类型、草食动物和农业耕作措施

  13. Isolating and Purifying Clostridium difficile Spores

    Science.gov (United States)

    Edwards, Adrianne N.; McBride, Shonna M.

    2016-01-01

    Summary The ability for the obligate anaerobe, Clostridium difficile, to form a metabolically dormant spore is critical for the survival of this organism outside of the host. This spore form is resistant to a myriad of environmental stresses, including heat, desiccation and exposure to disinfectants and antimicrobials. These intrinsic properties of spores allow C. difficile to survive long-term in an oxygenated environment, to be easily transmitted from host-to-host and to persist within the host following antibiotic treatment. Because of the importance of the spore form to the C. difficile lifecycle and treatment and prevention of C. difficile infection (CDI), the isolation and purification of spores are necessary to study the mechanisms of sporulation and germination, investigate spore properties and resistances, and for use in animal models of CDI. This chapter provides basic protocols, in vitro growth conditions and additional considerations for purifying C. difficile spores for a variety of downstream applications. PMID:27507337

  14. Effect of Certain Pesticides on Spore Germination and Mycelial Growth of the Entomogenous Fungus Aschersonia aleyrodis%农药对虫生真菌粉虱座壳孢孢子萌发和菌丝生长的影响

    Institute of Scientific and Technical Information of China (English)

    邱君志; 黄志鹏; 潘洁茹; 谢雪钦; 朱炎平; 张绍升; 关雄

    2004-01-01

    The entomogenous fungus Aschersonia aleyrodis is a promising whitefly and scale insect control agent. Six widely used pesticides were assessed at the recommended concentrations for compatibility in vitro with A. aleyrodis. The effects of these pesticides on spore germination during the whole test periods (12, 15, 18, 21 and 24 h) and mycelial growth after 5 days of incubation at 25℃ were quantified. Generally, fenpropathrin and propargite had pronounced adverse effects on the fungus. These two pesticides either heavily impaired the development of the fungus or strongly inhibited its spore germination at 25℃ and resulted in fungistasis,which indicated that they were mostly incompatible. Imidacloprid, isocarbophos and amitraz had a stimulating effect on spore germination and the latter two showed a reversible inhibitory effect on the growth of fungus in the tests. However, carbendazim conducted a temporary stimulatory performance on spore germination but performed an inhibitory influence on hyphal development.%虫生真菌粉虱座壳孢Aschersonia aleyrodis是大有前途的粉虱和介壳虫杀虫剂.用6种大田常用农药在推荐浓度下,研究其在25℃下对座壳孢菌孢子萌发和菌丝生长的影响,发现甲氰菊酯和克螨特抑制其孢子萌发和菌丝生长,表明二者与本菌极不相容.吡虫啉、水胺硫磷和双甲脒能促进孢子萌发且后两者亦可加速菌丝生长,多菌灵对其孢子萌发起暂时促进作用然而抑制其菌丝生长.

  15. 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.

    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

  16. 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

  17. The composition of arbuscular mycorrhizal fungal communities differs among the roots, spores and extraradical mycelia associated with five Mediterranean plant species.

    Science.gov (United States)

    Varela-Cervero, Sara; Vasar, Martti; Davison, John; Barea, José Miguel; Öpik, Maarja; Azcón-Aguilar, Concepción

    2015-08-01

    Arbuscular mycorrhizal fungi (AMF) are essential constituents of most terrestrial ecosystems. AMF species differ in terms of propagation strategies and the major propagules they form. This study compared the AMF community composition of different propagule fractions - colonized roots, spores and extraradical mycelium (ERM) - associated with five Mediterranean plant species in Sierra de Baza Natural Park (Granada, Spain). AMF were identified using 454 pyrosequencing of the SSU rRNA gene. A total of 96 AMF phylogroups [virtual taxa (VT)] were detected in the study site, including 31 novel VT. After per-sample sequencing depth standardization, 71 VT were recorded from plant roots, and 47 from each of the spore and ERM fractions. AMF communities differed significantly among the propagule fractions, and the root-colonizing fraction differed among host plant species. Indicator VT were detected for the root (13 Glomus VT), spore (Paraglomus VT281, VT336, Pacispora VT284) and ERM (Diversispora VT62) fractions. This study provides detailed evidence from a natural system that AMF taxa are differentially allocated among soil mycelium, soil spores and colonized root propagules. This has important implications for interpreting AMF diversity surveys and designing applications of AMF in vegetation restoration.

  18. Long-Distance Wind-Dispersal of Spores in a Fungal Plant Pathogen: Estimation of Anisotropic Dispersal Kernels from an Extensive Field Experiment

    Science.gov (United States)

    Rieux, Adrien; Soubeyrand, Samuel; Bonnot, François; Klein, Etienne K.; Ngando, Josue E.; Mehl, Andreas; Ravigne, Virginie; Carlier, Jean; de Lapeyre de Bellaire, Luc

    2014-01-01

    Given its biological significance, determining the dispersal kernel (i.e., the distribution of dispersal distances) of spore-producing pathogens is essential. Here, we report two field experiments designed to measure disease gradients caused by sexually- and asexually-produced spores of the wind-dispersed banana plant fungus Mycosphaerella fijiensis. Gradients were measured during a single generation and over 272 traps installed up to 1000 m along eight directions radiating from a traceable source of inoculum composed of fungicide-resistant strains. We adjusted several kernels differing in the shape of their tail and tested for two types of anisotropy. Contrasting dispersal kernels were observed between the two types of spores. For sexual spores (ascospores), we characterized both a steep gradient in the first few metres in all directions and rare long-distance dispersal (LDD) events up to 1000 m from the source in two directions. A heavy-tailed kernel best fitted the disease gradient. Although ascospores distributed evenly in all directions, average dispersal distance was greater in two different directions without obvious correlation with wind patterns. For asexual spores (conidia), few dispersal events occurred outside of the source plot. A gradient up to 12.5 m from the source was observed in one direction only. Accordingly, a thin-tailed kernel best fitted the disease gradient, and anisotropy in both density and distance was correlated with averaged daily wind gust. We discuss the validity of our results as well as their implications in terms of disease diffusion and management strategy. PMID:25116080

  19. Long-distance wind-dispersal of spores in a fungal plant pathogen: estimation of anisotropic dispersal kernels from an extensive field experiment.

    Directory of Open Access Journals (Sweden)

    Adrien Rieux

    Full Text Available Given its biological significance, determining the dispersal kernel (i.e., the distribution of dispersal distances of spore-producing pathogens is essential. Here, we report two field experiments designed to measure disease gradients caused by sexually- and asexually-produced spores of the wind-dispersed banana plant fungus Mycosphaerella fijiensis. Gradients were measured during a single generation and over 272 traps installed up to 1000 m along eight directions radiating from a traceable source of inoculum composed of fungicide-resistant strains. We adjusted several kernels differing in the shape of their tail and tested for two types of anisotropy. Contrasting dispersal kernels were observed between the two types of spores. For sexual spores (ascospores, we characterized both a steep gradient in the first few metres in all directions and rare long-distance dispersal (LDD events up to 1000 m from the source in two directions. A heavy-tailed kernel best fitted the disease gradient. Although ascospores distributed evenly in all directions, average dispersal distance was greater in two different directions without obvious correlation with wind patterns. For asexual spores (conidia, few dispersal events occurred outside of the source plot. A gradient up to 12.5 m from the source was observed in one direction only. Accordingly, a thin-tailed kernel best fitted the disease gradient, and anisotropy in both density and distance was correlated with averaged daily wind gust. We discuss the validity of our results as well as their implications in terms of disease diffusion and management strategy.

  20. In vitro and in vivo analyses of the Bacillus anthracis spore cortex lytic protein SleL

    OpenAIRE

    2012-01-01

    The bacterial endospore is the most resilient biological structure known. Multiple protective integument layers shield the spore core and promote spore dehydration and dormancy. Dormancy is broken when a spore germinates and becomes a metabolically active vegetative cell. Germination requires the breakdown of a modified layer of peptidoglycan (PG) known as the spore cortex. This study reports in vitro and in vivo analyses of the Bacillus anthracis SleL protein. SleL is a spore cortex lytic en...

  1. Regulation of the Spore Cortex Lytic Enzyme SleB in Bacillus anthracis

    OpenAIRE

    2014-01-01

    Bacillus anthracis is the causative agent of the disease anthrax and poses a threat due to its potential to be used as a biological weapon. The spore form of this bacterium is an extremely resistant structure, making spore decontamination exceptionally challenging. During spore germination, nutrient germinants interact with Ger receptors, triggering a cascade of events. A crucial event in this process is degradation of the cortex peptidoglycan by germination-specific lytic enzymes (GSLEs),...

  2. Measurements of DNA Damage and Repair in Bacillus anthracis Sterne Spores by UV Radiation

    Science.gov (United States)

    2014-09-18

    increase of water, protein motility begins and enzymatic activity is initiated. The outgrowth period of germination is the only step that contains...process [23]. 17 Figure 5. The spore germination process. Germination occurs in 2 main stages. The initiation/activation step involves the...with a red fluorescent protein was transformed into Ba Sterne cells prior. Following irradiation, germination media was added and the spores were

  3. Analysis of germination capacity and germinant receptor (sub)clusters of genomesequenced Bacillus cereus environmental isolates and model strains

    NARCIS (Netherlands)

    Warda, Alicja K.; Xiao, Yinghua; Boekhorst, Jos; Wells-Bennik, Marjon H.J.; Nierop Groot, Masja N.; Abee, Tjakko

    2017-01-01

    Spore germination of 17 Bacillus cereus food isolates and reference strains was evaluated using flow cytometry analysis in combination with fluorescent staining at a single-spore level. This approach allowed for rapid collection of germination data under more than 20 conditions, including heat ac

  4. 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.

  5. A survey of airborne fungal spores and their relationships with climate in Taizhou city Huangyan area%台州市黄岩区气传真菌散布规律与气候关系的研究

    Institute of Scientific and Technical Information of China (English)

    任应鹏; 阮荣华; 叶雅丽

    2015-01-01

    Objective To investigate the species,amount and seasonal distribution of airborne fungi spores and the effect of meteorological factors on airborne fungal spores in Taizhou city Huangyan area.Methods Various air samples in the designated areas in Taizhou city Huangyan area were harvested with the national standardized fungal sampler on dialy basis from Sep.1th,2013 to August. 31th,2014. Airborne fungi were quantitatively counted under microscope.Results The fungi aerosols were present throughout whole year. More than 20 categories of airborne fungi were found and among which the most dominate fungi were,Tripospernum sp,Ustsilagianles,Ciadosporium sp,Uredinales,etc.Conclusions The air borne fungi can be found throughout the year,and weather shown a significant correlation with the number of airborne fungal spores.%目的:调查台州市黄岩区空气中致敏真菌种类、数量,了解气传真菌的散布与季节、天气变化的消长规律,对本地区真菌过敏性变态反应疾病的诊断和防治提供参考。方法:采用全国统一标准连续24小时曝片法,在台州市黄岩区设曝片点,每日定时换片并记录当日气象资料(温度、相对湿度、降雨量等),收集2013年9月01日至2014年8月31日一年中气传真菌样品和气象资料。每天在显微镜下统计真菌孢子或菌丝。结果:台州市黄岩区空气中全年都有真菌孢子飘散,4至9月份月均收集到的真菌孢子数较多,为真菌孢子飘散的相对高峰期,10月至次年3月月均收集到的真菌孢子数较少,为飘散的相对低谷期。全年曝片共收集到真菌孢子6884个,其中链格孢菌4056个(59.92%)、黑粉菌842(12.23%)、枝孢菌349个(5.10%)、小球腔菌236个(3.43%)、锈菌227个(3.3%)等。结论:台州市黄岩区全年均有气传真菌分布,链格孢菌、黑粉菌、枝孢菌是空气中的优势菌种。气温和降雨量是影响气传真菌

  6. Phosphoproteome dynamics mediate revival of bacterial spores

    OpenAIRE

    2015-01-01

    Background Bacterial spores can remain dormant for decades, yet harbor the exceptional capacity to rapidly resume metabolic activity and recommence life. Although germinants and their corresponding receptors have been known for more than 30 years, the molecular events underlying this remarkable cellular transition from dormancy to full metabolic activity are only partially defined. Results Here, we examined whether protein phospho-modifications occur during germination, the first step of exit...

  7. 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

  8. Effects of Chlorine Dioxide on Spore Structural and Fuctional Properties

    Science.gov (United States)

    2006-05-31

    A., Price, B., Leighton, T. and K. Wheeler. 2003. Kinetics of size changes of individual Bacillus thuringiensis spores in response to changes in...vegetative growth . The germination process involves a defined temporal order of events, characterized initially by hydrolysis of the spore coat and...capable of early germination but not resumption of vegetative growth and cell division. We have explored the use of rapid spectrophotometric assays to

  9. Nitric oxide and reactive oxygen species coordinately regulate the germination of Puccinia striiformis f. sp. tritici urediniospores

    Directory of Open Access Journals (Sweden)

    Shuining eYin

    2016-02-01

    Full Text Available Nitric oxide (NO and reactive oxygen species (ROS function as signaling molecules in a number of critical signal transduction pathways in plants, including plant biotic interactions. In addition to the role of plant-derived NO and ROS in plant resistance, which has been well documented, pathogen-produced NO and ROS have recently emerged as important players in fungal development and pathogenesis. However, the effects of pathogenic fungi-derived NO and ROS on signaling pathways during fungal pre-infection development remain unknown. Here, using a combination of pharmacological approaches and confocal microscopy, we investigated the roles of NO and ROS during the germination of Puccinia striiformis Westend f. sp. tritici (Pst the wheat stripe rust pathogen. Both NO and ROS have a crucial role in uredinial germination. The scavengers of NO and ROS delayed spore germination and decreased the lengths of germ tubes. A similar phenotype was produced after treatment with the promoter. However, the spores germinated and grew normally when the levels of NO and ROS were simultaneously elevated by the application of a promoter of NO and a donor of ROS. Confocal laser microscopy indicated that both NO and ROS preferentially localized at the germ pores and apexes of growing germ tubes when the ROS/NO ratio in the spores was maintained in a specific range. We concluded that both NO and ROS are critical signaling molecules in the pre-infection development of Pst and that the polar growth of the germ tube is coordinately regulated by NO and ROS.

  10. Effect of chromium toxicity on germination and early seedling growth ...

    African Journals Online (AJOL)

    USER

    2010-07-19

    Jul 19, 2010 ... causing toxicity to plants as exhibited by reduced seed germination ... hypochlorite for 1 min to prevent fungal attack, and triple-rinsed in distilled ..... Effects of arsenic on seed germination and physiological activities of wheat.

  11. 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.

  12. Fern spore longevity in saline water: can sea bottom sediments maintain a viable spore bank?

    Science.gov (United States)

    de Groot, G Arjen; During, Heinjo

    2013-01-01

    Freshwater and marine sediments often harbor reservoirs of plant diaspores, from which germination and establishment may occur whenever the sediment falls dry. Therewith, they form valuable records of historical inter- and intraspecific diversity, and are increasingly exploited to facilitate diversity establishment in new or restored nature areas. Yet, while ferns may constitute a considerable part of a vegetation's diversity and sediments are known to contain fern spores, little is known about their longevity, which may suffer from inundation and--in sea bottoms--salt stress. We tested the potential of ferns to establish from a sea or lake bottom, using experimental studies on spore survival and gametophyte formation, as well as a spore bank analysis on sediments from a former Dutch inland sea. Our experimental results revealed clear differences among species. For Asplenium scolopendrium and Gymnocarpium dryopteris, spore germination was not affected by inundated storage alone, but decreased with rising salt concentrations. In contrast, for Asplenium trichomanes subsp. quadrivalens germination decreased following inundation, but not in response to salt. Germination rates decreased with time of storage in saline water. Smaller and less viable gametophytes were produced when saline storage lasted for a year. Effects on germination and gametophyte development clearly differed among genotypes of A. scolopendrium. Spore bank analyses detected no viable spores in marine sediment layers. Only two very small gametophytes (identified as Thelypteris palustris via DNA barcoding) emerged from freshwater sediments. Both died before maturation. We conclude that marine, and likely even freshwater sediments, will generally be of little value for long-term storage of fern diversity. The development of any fern vegetation on a former sea floor will depend heavily on the deposition of spores onto the drained land by natural or artificial means of dispersal.

  13. Concentrations of butyric acid bacteria spores in silage and relationships with aerobic deterioration

    NARCIS (Netherlands)

    Vissers, M.M.M.; Driehuis, F.; Giffel, M.C.T.; Jong, de P.; Lankveld, J.M.G.

    2007-01-01

    Germination and growth of spores of butyric acid bacteria ( BAB) may cause severe defects in semihard cheeses. Silage is the main source of BAB spores in cheese milk. The objectives of the study were to determine the significance of grass silages and corn silages as sources of BAB spores and to inve

  14. 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.

  15. Ecology and thermal inactivation of microbes in and on interplanetary space vehicle components. [heat sensitivity of bacterial spores

    Science.gov (United States)

    Campbell, J. E.; Reyes, A. L.; Wehby, A. J.; Crawford, R. G.; Wimsatt, J. C.; Peeler, J. T.

    1973-01-01

    The mechanism for thermal inactivation of bacterial spores under moist or dry heat was studied. Experimental conditions were established relating to spore loss of heat resistance and loss of optical density as a measure of the rate and extent of germination in spore suspensions. Events occurring during germination were correlated with phase darkening (refractility and non-refractility of spores), stainability characteristics of heat and non-heat treated spores, morphological characteristics, and studies on swelling of spores by an increase in packed cell volume.

  16. Germination of Bacillus cereus spores : the role of germination receptors

    NARCIS (Netherlands)

    Hornstra, L.M.

    2007-01-01

    The Bacillus cereus sensu lato group forms a highly homogeneous subdivision of the genus Bacillus and comprises several species that are relevant for humans. Notorious is Bacillus anthracis, the cause of the often-lethal disease anthrax, while the insect pathogen Bacillus thuringiensis is of economi

  17. 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 fungus, pigmented spores are viable and unpigmented spores are inviable. These results show that while both parents influence all these traits, maternal influence is strongest on both fertility and mortality traits until the spores are physiologically independent of the maternal cytoplasm......., 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...

  18. The molecular timeline of a reviving bacterial spore.

    Science.gov (United States)

    Sinai, Lior; Rosenberg, Alex; Smith, Yoav; Segev, Einat; Ben-Yehuda, Sigal

    2015-02-19

    The bacterial spore can rapidly convert from a dormant to a fully active cell. Here we study this remarkable cellular transition in Bacillus subtilis and reveal the identity of the newly synthesized proteins throughout spore revival. Our analysis uncovers a highly ordered developmental program that correlates with the spore morphological changes and reveals the spatial and temporal molecular events fundamental to reconstruct a cell. As opposed to current knowledge, we found that translation takes place during the earliest revival event, termed germination, a process hitherto considered to occur without the need for any macromolecule synthesis. Furthermore, we demonstrate that translation is required for execution of germination and relies on the bona fide translational factors RpmE and Tig. Our study sheds light on the spore revival process and on the vital building blocks underlying cellular awakening, thereby paving the way for designing new antimicrobial agents to eradicate spore-forming pathogens.

  19. Formation of non-viable spores of Dictyostelium discoideum by UV-irradiation and caffeine

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, T.; Hazama, M.; Okaichi, K.; Nozu, K. (Nara Medical Univ., Kashihara (Japan))

    1982-09-01

    The spores formed from amoeboid cells of the wild type strain of Dictyostelium discoideum after UV-irradiation were characterized. Cell differentiation in the presence of caffeine after a fluence of 300 J/m/sup 2/ resulted in a population of spores which was 98% non-viable. The UV-irradiation did not affect the conversion of the spores to swollen spores but did affect the conversion of swollen spores to amoeboid cells. When the germination of the spores was done without caffeine, only a small effect on conversion of swollen spores to amoeboid cells and on the beginning of growth was detected. On the other hand, in the presence of caffeine, the spores had a remarkable delay in both. It was also shown that few, if any, pyrimidine dimers exist in the DNA of the non-viable spores. Possible mechanisms of formation of non-viable spores are discussed.

  20. Relationship of the syntheses of spore coat protein and parasporal crystal protein in Bacillus thuringiensis.

    Science.gov (United States)

    Aronson, A I; Tyrell, D J; Fitz-James, P C; Bulla, L A

    1982-01-01

    Two major classes of polypeptides were extracted from the spore surface of Bacillus thuringiensis subsp. kurstaki: the 134,000-dalton protoxin that is the major component of the crystalline inclusion and spore coat polypeptides very similar to those found on Bacillus cereus spores. The quantity of spore coat polypeptides produced was reduced when compared with that produced by certain acrystalliferous mutants or by B. thuringiensis subsp. israelensis. The latter organism produced an inclusion toxic to mosquito larvae, but deposited very little of the inclusion protein on the spore surface. The reduction in spore coat protein in B. thuringiensis subsp. kurstaki was also seen in freeze-etched electron micrographs of spores. B. thuringiensis subsp. kurstaki spores germinated rather slowly when compared with related species, a property previously correlated with a deficiency or defect of the spore coat. Many mutants of B. thuringiensis subsp. kurstaki unable to form a crystalline inclusion were nontoxic and lacked a well-defined spore coat. Other mutants isolated either directly from the wild type or from coat-deficient mutants produced spores that were identical to those produced by the closely related species. Bacillus cereus, on the basis of morphology, germination rate, and the size and antigenicity of the spore coat polypeptides. Most of the protein extractable from the inclusion produced by B. thuringiensis subsp. israelensis was about 26,000 daltons, considerably smaller than the major polypeptide extractable from other inclusions. Some of the B. thuringiensis subsp. israelensis inclusion protein was found on the spore surface, but the majority of the extractable spore coat protein was the same size and antigenicity as that found on B. cereus spores. The B. thuringiensis subsp. israelensis spores germinated at a rate close to that of B. cereus, especially when the spores were formed at 37 degrees C, and the morphology of the spore surface was very similar to

  1. Effects of Ionizing Radiation on Postharvest Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Rae-Dong Jeong

    2015-06-01

    Full Text Available Postharvest diseases cause losses in a wide variety of crops around the world. Irradiation, a useful nonchemical approach, has been used as an alternative treatment for fungicide to control plant fungal pathogens. For a preliminary study, ionizing radiations (gamma, X-ray, or e-beam irradiation were evaluated for their antifungal activity against Botrytis cinerea, Penicillium expansum, and Rhizopus stolonifer through mycelial growth, spore germination, and morphological analysis under various conditions. Different fungi exhibited different radiosensitivity. The inhibition of fungal growth showed in a dose-dependent manner. Three fungal pathogens have greater sensitivity to the e-beam treatment compared to gamma or X-ray irradiations. The inactivation of individual fungal-viability to different irradiations can be considered between 3–4 kGy for B. cinerea and 1–2 kGy for P. expansum and R. stolonifer based on the radiosensitive and radio-resistant species, respectively. These preliminary data will provide critical information to control postharvest diseases through radiation.

  2. Mushroom spore dispersal by convectively-driven winds

    CERN Document Server

    Dressaire, Emilie; Song, Boya; Roper, Marcus

    2015-01-01

    Thousands of fungal species rely on mushroom spores to spread across landscapes. It has long been thought that spores depend on favorable airflows for dispersal -- that active control of spore dispersal by the parent fungus is limited to an impulse delivered to the spores to carry them clear of the gill surface. Here we show that evaporative cooling of the air surrounding the mushroom pileus creates convective airflows capable of carrying spores at speeds of centimeters per second. Convective cells can transport spores from gaps that may be only a centimeter high, and lift spores ten centimeters or more into the air. The work reveals how mushrooms tolerate and even benefit from crowding, and provides a new explanation for their high water needs.

  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. Water-, pH- and temperature relations of germination for the extreme xerophiles Xeromyces bisporus (FRR 0025), Aspergillus penicillioides (JH06THJ) and Eurotium halophilicum (FRR 2471).

    Science.gov (United States)

    Stevenson, Andrew; Hamill, Philip G; Dijksterhuis, Jan; Hallsworth, John E

    2017-03-01

    Water activity, temperature and pH are determinants for biotic activity of cellular systems, biosphere function and, indeed, for all life processes. This study was carried out at high concentrations of glycerol, which concurrently reduces water activity and acts as a stress protectant, to characterize the biophysical capabilities of the most extremely xerophilic organisms known. These were the fungal xerophiles: Xeromyces bisporus (FRR 0025), Aspergillus penicillioides (JH06THJ) and Eurotium halophilicum (FRR 2471). High-glycerol spores were produced and germination was determined using 38 media in the 0.995-0.637 water activity range, 33 media in the 2.80-9.80 pH range and 10 incubation temperatures, from 2 to 50°C. Water activity was modified by supplementing media with glycerol+sucrose, glycerol+NaCl and glycerol+NaCl+sucrose which are known to be biologically permissive for X. bisporus, A. penicillioides and E. halophilicum respectively. The windows and rates for spore germination were quantified for water activity, pH and temperature; symmetry/asymmetry of the germination profiles were then determined in relation to supra- and sub-optimal conditions; and pH- and temperature optima for extreme xerophilicity were quantified. The windows for spore germination were ~1 to 0.637 water activity, pH 2.80-9.80 and > 10 and < 44°C, depending on strain. Germination profiles in relation to water activity and temperature were asymmetrical because conditions known to entropically disorder cellular macromolecules, i.e. supra-optimal water activity and high temperatures, were severely inhibitory. Implications of these processes were considered in relation to the in-situ ecology of extreme conditions and environments; the study also raises a number of unanswered questions which suggest the need for new lines of experimentation. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  5. Adenosine Monophosphate-Based Detection of Bacterial Spores

    Science.gov (United States)

    Kern, Roger G.; Chen, Fei; Venkateswaran, Kasthuri; Hattori, Nori; Suzuki, Shigeya

    2009-01-01

    A method of rapid detection of bacterial spores is based on the discovery that a heat shock consisting of exposure to a temperature of 100 C for 10 minutes causes the complete release of adenosine monophosphate (AMP) from the spores. This method could be an alternative to the method described in the immediately preceding article. Unlike that method and related prior methods, the present method does not involve germination and cultivation; this feature is an important advantage because in cases in which the spores are those of pathogens, delays involved in germination and cultivation could increase risks of infection. Also, in comparison with other prior methods that do not involve germination, the present method affords greater sensitivity. At present, the method is embodied in a laboratory procedure, though it would be desirable to implement the method by means of a miniaturized apparatus in order to make it convenient and economical enough to encourage widespread use.

  6. CLOSTRIDIUM SPORE ATTACHMENT TO HUMAN CELLS

    Energy Technology Data Exchange (ETDEWEB)

    PANESSA-WARREN,B.; TORTORA,G.; WARREN,J.

    1997-08-10

    This paper uses high resolution scanning electron microscopy (SEM) with a LaB6 gun and the newest commercial field emission guns, to obtain high magnification images of intact clostridial spores throughout the activation/germination/outgrowth process. By high resolution SEM, the clostridial exosporial membrane can be seen to produce numerous delicate projections (following activation), that extend from the exosporial surface to a nutritive substrate (agar), or cell surface when anaerobically incubated in the presence of human cells (embryonic fibroblasts and colon carcinoma cells). Magnifications of 20,000 to 200,000Xs at accelerating voltages low enough to minimize or eliminate specimen damage (1--5 kV) have permitted the entire surface of C.sporogenes and C.difficile endospores to be examined during all stages of germination. The relationships between the spore and the agar or human cell surface were also clearly visible.

  7. Structural Analysis of Bacillus subtilis Spore Peptidoglycan during Sporulation

    OpenAIRE

    2000-01-01

    A major structural element of bacterial endospores is a peptidoglycan (PG) wall. This wall is produced between the two opposed membranes surrounding the developing forespore and is composed of two layers. The inner layer is the germ cell wall, which appears to have a structure similar to that of the vegetative cell wall and which serves as the initial cell wall following spore germination. The outer layer, the cortex, has a modified structure, is required for maintenance of spore dehydration,...

  8. Comparison of the properties of Bacillus subtilis spores made in liquid or on agar plates.

    Science.gov (United States)

    Rose, R; Setlow, B; Monroe, A; Mallozzi, M; Driks, A; Setlow, P

    2007-09-01

    To compare the properties of the spores of Bacillus subtilis prepared in liquid and on plates. The spores of B. subtilis were prepared at 37 degrees C using a nutrient exhaustion medium either in liquid or on agar plates. The levels of core water, dipicolinic acid (DPA) and small, acid-soluble spore proteins (SASP) were essentially identical in spores made in liquid or on plates. Spores prepared in liquid were killed approximately threefold more rapidly at 90 degrees C in water than the spores prepared on plates, and the spores prepared in liquid were more sensitive to nitrous acid and a diluted stable superoxidized water. Spores prepared in liquid also germinated more rapidly with several agents than those prepared on plates. Pellets of spores prepared on plates were darker than spores prepared in liquid, and spores prepared in liquid had more readily extracted coat protein. However, there were no major differences in the relative levels of individual coat proteins or the cross-linking of the coat protein GerQ in the two types of spores, although the inner membrane of spores prepared on plates had a higher ratio of anteiso- to iso-fatty acids. The preparation in liquid yielded spores with some different properties than those made on agar plates. Spores made in liquid had lower resistance to heat and several chemicals, and germinated more readily with several agents. There were also differences in the composition of the inner membrane of spores prepared under these two conditions. However, there were no major differences in the levels of DPA, core water, SASP and individual coat proteins or the cross-linking of a coat protein in spores made in liquid and on plates. This work demonstrates that the preparation method can affect the resistance and germination properties of bacterial spores, even if an identical medium and temperature are used. Evidence was also obtained consistent with the role of the inner membrane in spore resistance and germination, and that some

  9. Airborne Spore Analysis of Karabük Atmosphere

    Directory of Open Access Journals (Sweden)

    Ayşe Kaplan

    2014-05-01

    Full Text Available In order to identify types and amounts of airborne allergenic spore dispersal in the atmosphere of Karabük by gravimetric method in 2006 and 2007, two Durham samplers were situated on roof and garden of Technical Education Faculty of Karabük University between the dates January 1, 2006 and December 31, 2007. As a result of the analysis a total of 2822.2±625.01 spore/cm2 spore quantity belonging to 21 types was identified. Of this total, 1106±250.33 spore/cm² was observed in 2006 and 1716±374.68 spore/cm² was observed in 2007. Spore concentrations revealed no statistically differences between two samplers (t=0.1527-1.1355, p>0.05. The relationship between spore concentrations and meteorological factors was displayed by Spearman Correlation analysis. The highest quantity of fungal spores and Myxomycetes were determined in June and July. Cladosporium, Alternaria, Ustilago, Myxomycetes and unidentified Ascomycetes spores were recorded as dominant. In the end of this study, a two-year spore calendar was prepared.

  10. Bacillus subtilis spore protein SpoVAC functions as a mechanosensitive channel

    NARCIS (Netherlands)

    Velasquez Guzman, Jeanette; Schuurman-Wolters, Geesina; Birkner, Jan Peter; Abee, Tjakko; Poolman, Bert

    2014-01-01

    A critical event during spore germination is the release of Ca-DPA (calcium in complex with dipicolinic acid). The mechanism of release of Ca-DPA through the inner membrane of the spore is not clear, but proteins encoded by the Bacillus subtilis spoVA operon are involved in the process. We cloned an

  11. Challenges in risk assessment and predictive microbiology of foodborne spore-forming bacteria.

    Science.gov (United States)

    Augustin, Jean-Christophe

    2011-04-01

    Mathematical description of the behavior of bacterial foodborne pathogens and concepts of risk assessment were first applied to spore-forming bacteria and specially to Clostridium botulinum with numerous works dealing with spores heat destruction to ensure the safety of canned foods or with their germination and growth probability in foods. This paper discusses two aspects which appear specific to pathogenic sporeformers in comparison to vegetative microorganisms, that is, firstly, the extreme intra-species biodiversity of spore-forming bacteria and its consequences for risk assessment and, secondly, the modeling of spore germination and outgrowth processes. The intra-species biodiversity of spore-forming bacteria has a great impact on hazard identification, exposure assessment and hazard characterization leading thus to an extremely variable individual poisoning risk for consumers. The germination and outgrowth processes were shown independent at the single cell level and although numerous studies were performed to study the effect of spores treatments and growth conditions on these two events, the mathematical modeling and the prediction of these processes is still challenging today. The difficulties to accurately assess the biodiversity and the germination and outgrowth processes of spore-forming bacteria lead to a substantial uncertainty in risk estimates related to the exposure to these microorganisms. Nevertheless, significant progress have been made these last years improving the relevance of quantitative risk assessments for spore-forming bacteria and decreasing the risk uncertainty. Despite these difficulties, risk assessment still constitutes a valuable tool to justify the implementation of management options.

  12. Quantitative and Sensitive RNA Based Detection of Bacillus Spores

    Directory of Open Access Journals (Sweden)

    Ekaterina eOsmekhina

    2014-03-01

    Full Text Available The fast and reliable detection of bacterial spores is of great importance and still remains a challenge. Here we describe a direct RNA based diagnostic method for the specific detection of viable bacterial spores which does not depends on an enzymatic amplification step and therefore is directly appropriate for quantification. The procedure includes the following steps: (i heat activation of spores, (ii germination and enrichment cultivation, (iii cell lysis, and (iv analysis of 16S rRNA in crude cell lysates using a sandwich hybridization assay. The sensitivity of the method is dependent on the cultivation time and the detection limit; it is possible to detect 10 spores per ml when the RNA analysis is performed after 6 h of enrichment cultivation. At spore concentrations above 106 spores per ml the cultivation time can be shortened to 30 min. Total analysis times are in the range of 2 to 8 hours depending on the spore concentration in samples. The developed procedure is optimized at the example of Bacillus subtilis spores but should be applicable to other organisms. The new method can easily be modified for other target RNAs and is suitable for specific detection of spores from known groups of organisms.

  13. Comparison of sampling methods to recover germinated Bacillus anthracis and Bacillus thuringiensis endospores from surface coupons.

    Science.gov (United States)

    Mott, T M; Shoe, J L; Hunter, M; Woodson, A M; Fritts, K A; Klimko, C P; Quirk, A V; Welkos, S L; Cote, C K

    2017-05-01

    In an attempt to devise decontamination methods that are both effective and minimally detrimental to the environment, we evaluated germination induction as an enhancement to strategies for Bacillus anthracis spore decontamination. To determine an optimal method for the recovery of germinating spores from different matrices, it was critical to ensure that the sampling procedures did not negatively impact the viability of the germinating spores possibly confounding the results and downstream analyses of field trial data. Therefore, the two main objectives of this study were the following: (i) development of an effective processing protocol capable of recovering the maximum number of viable germinating or germinated spores from different surface materials; and (ii) using a model system of spore contamination, employ this protocol to evaluate the potential applicability of germination induction to wide-area decontamination of B. anthracis spores. We examined parameters affecting the sampling efficiencies of B. anthracis and the surrogate species Bacillus thuringiensis on nonporous and porous materials. The most efficient extraction from all matrices was observed using PBS with 0·01% Tween 80 extraction buffer. The addition of a sonication and/or extended vortex treatment did not yield significant increases in spore or germinated spore recovery. Our data demonstrate that previous germination-induction experiments performed in suspension can be reproduced when Bacillus spores are deposited onto reference surfaces materials. Our proof of concept experiment illustrated that a germination pretreatment step significantly improves conventional secondary decontamination strategies and remediation plans. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  14. Aerodynamic characteristics and respiratory deposition of fungal fragments

    Science.gov (United States)

    Cho, Seung-Hyun; Seo, Sung-Chul; Schmechel, Detlef; Grinshpun, Sergey A.; Reponen, Tiina

    The purpose of this study was to investigate the aerodynamic characteristics of fungal fragments and to estimate their respiratory deposition. Fragments and spores of three different fungal species ( Aspergillus versicolor, Penicillium melinii, and Stachybotrys chartarum) were aerosolized by the fungal spore source strength tester (FSSST). An electrical low-pressure impactor (ELPI) measured the size distribution in real-time and collected the aerosolized fungal particles simultaneously onto 12 impactor stages in the size range of 0.3-10 μm utilizing water-soluble ZEF-X10 coating of the impaction stages to prevent spore bounce. For S. chartarum, the average concentration of released fungal fragments was 380 particles cm -3, which was about 514 times higher than that of spores. A. versicolor was found to release comparable amount of spores and fragments. Microscopic analysis confirmed that S. chartarum and A. versicolor did not show any significant spore bounce, whereas the size distribution of P. melinii fragments was masked by spore bounce. Respiratory deposition was calculated using a computer-based model, LUDEP 2.07, for an adult male and a 3-month-old infant utilizing the database on the concentration and size distribution of S. chartarum and A. versicolor aerosols measured by the ELPI. Total deposition fractions for fragments and spores were 27-46% and 84-95%, respectively, showing slightly higher values in an infant than in an adult. For S. chartarum, fragments demonstrated 230-250 fold higher respiratory deposition than spores, while the number of deposited fragments and spores of A. versicolor were comparable. It was revealed that the deposition ratio (the number of deposited fragments divided by that of deposited spores) in the lower airways for an infant was 4-5 times higher than that for an adult. As fungal fragments have been shown to contain mycotoxins and antigens, further exposure assessment should include the measurement of fungal fragments for

  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. 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

    germination using phase contrast and fluorescence microscopy, Raman spectroscopy and optical tweezers, Nature Protocols , (04 2011): . doi: 05/11...multiple individual spores [ Nature Protocols , 6, 625 (2011)]. (1e) We developed a multiple-trap laser tweezers Raman spectroscopy (LTRS) array for

  17. Effects of Endogenous d-Alanine Synthesis and Autoinhibition of Bacillus anthracis Germination on In Vitro and In Vivo Infections▿

    OpenAIRE

    McKevitt, Matthew T.; Bryant, Katie M.; Shakir, Salika M.; Larabee, Jason L.; Blanke, Steven R.; Lovchik, Julie; Lyons, C. Rick; Ballard, Jimmy D.

    2007-01-01

    Bacillus anthracis transitions from a dormant spore to a vegetative bacillus through a series of structural and biochemical changes collectively referred to as germination. The timing of germination is important during early steps in infection and may determine if B. anthracis survives or succumbs to responsive macrophages. In the current study experiments determined the contribution of endogenous d-alanine production to the efficiency and timing of B. anthracis spore germination under in vit...

  18. 不同条件下韭菜汁对香蕉枯萎病菌4号小种活性抑制的研究%The inhibitory activities of spore germination of Fusarium oxysporum f.sp. cubense race 4 with Allium tuberosum juice under different conditions

    Institute of Scientific and Technical Information of China (English)

    刘任; 杨静美; 梁小媚; 陈雁; 冯岩; 杜洪忠

    2012-01-01

    研究了不同温度、pH值、杀虫剂和杀菌剂的影响下,韭菜汁对香蕉枯萎病菌4号小种的抑制作用,以确定韭菜汁在不同条件影响下对病菌的活力。结果表明,在试验的各温度处理后,55℃以上的温度对韭菜汁的成分有破坏作用,菌落的生长受到显著影响。韭菜根汁对病菌孢子的抑制作用不受pH值的影响。酸性至弱碱性情况下,韭菜茎汁对病菌孢子萌发的抑制率为100%;在强碱性条件下,韭菜茎汁中物质的活性促进了孢子的萌发。供试杀虫剂和杀菌剂对韭菜汁的成分无明显破坏作用。%Study on the impact of different temperatures and pH,insecticides and fungicides of Fusarium oxysporum f.sp.cubense race 4 to confirm the vigour with Allium tuberosum juice under different conditions.The results showed that above 55℃,active ingredients in Allium tuberosum juice were destroyed,and seriously affected the growth of colonies.All of the inhibitory rate of spores with Allium tuberosum root juice were 100% at the pH 2 to 11.The tested inhibitory rate of stem juice to the spores were also 100% at the pH 2 to 9,but promoted the germination of spores when the pH was 10 to 11.Some insecticides and fungicides showed little damages to the active ingredients of Allium tuberosum juice.

  19. Subseafloor basalts as fungal habitats

    Science.gov (United States)

    Ivarsson, M.

    2012-09-01

    The oceanic crust is believed to host the largest potential habitat for microbial life on Earth, yet, still we lack substantial information about the abundance, diversity, and consequence of its biosphere. The last two decades have involved major research accomplishments within this field and a change in view of the ocean crust and its potential to harbour life. Here fossilised fungal colonies in subseafloor basalts are reported from three different seamounts in the Pacific Ocean. The fungal colonies consist of various characteristic structures interpreted as fungal hyphae, fruit bodies and spores. The fungal hyphae are well preserved with morphological characteristics such as hyphal walls, septa, thallic conidiogenesis, and hyphal tips with hyphal vesicles within. The fruit bodies consist of large (∼50-200 µm in diameter) body-like structures with a defined outer membrane and an interior filled with calcite. The fruit bodies have at some stage been emptied of their contents of spores and filled by carbonate-forming fluids. A few fruit bodies not filled by calcite and with spores still within support this interpretation. Spore-like structures (ranging from a few µm to ∼20 µm in diameter) are also observed outside of the fruit bodies and in some cases concentrated to openings in the membrane of the fruit bodies. The hyphae, fruit bodies and spores are all closely associated with a crust lining the vein walls that probably represent a mineralized biofilm. The results support a fungal presence in deep subseafloor basalts and indicate that such habitats were vital between ∼81 and 48 Ma.

  20. 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

  1. 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

  2. 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

  3. Impact of sorbic acid on germinant receptor-dependent and -independent germination pathways in Bacillus cereus

    NARCIS (Netherlands)

    Melis, van C.C.J.; Nierop Groot, M.N.; Abee, T.

    2011-01-01

    Amino acid- and inosine-induced germination of Bacillus cereus ATCC 14579 spores was reversibly inhibited in the presence of 3 mM undissociated sorbic acid. Exposure to high hydrostatic pressure, Ca-dipicolinic acid (DPA), and bryostatin, an activator of PrkC kinase, negated this inhibition,

  4. Hydrazine inactivates bacillus spores

    Science.gov (United States)

    Schubert, Wayne; Plett, G. A.; Yavrouian, A. H.; Barengoltz, J.

    2005-01-01

    Planetary Protection places requirements on the maximum number of viable bacterial spores that may be delivered by a spacecraft to another solar system body. Therefore, for such space missions, the spores that may be found in hydrazine are of concern. A proposed change in processing procedures that eliminated a 0.2 um filtration step propmpted this study to ensure microbial contamination issue existed, especially since no information was found in the literature to substantiate bacterial spore inactivation by hydrazine.

  5. Gene discovery in EST sequences from the wheat leaf rust fungus Puccinia triticina sexual spores, asexual spores and haustoria, compared to other rust and corn smut fungi

    Directory of Open Access Journals (Sweden)

    Wynhoven Brian

    2011-03-01

    Full Text Available Abstract Background Rust fungi are biotrophic basidiomycete plant pathogens that cause major diseases on plants and trees world-wide, affecting agriculture and forestry. Their biotrophic nature precludes many established molecular genetic manipulations and lines of research. The generation of genomic resources for these microbes is leading to novel insights into biology such as interactions with the hosts and guiding directions for breakthrough research in plant pathology. Results To support gene discovery and gene model verification in the genome of the wheat leaf rust fungus, Puccinia triticina (Pt, we have generated Expressed Sequence Tags (ESTs by sampling several life cycle stages. We focused on several spore stages and isolated haustorial structures from infected wheat, generating 17,684 ESTs. We produced sequences from both the sexual (pycniospores, aeciospores and teliospores and asexual (germinated urediniospores stages of the life cycle. From pycniospores and aeciospores, produced by infecting the alternate host, meadow rue (Thalictrum speciosissimum, 4,869 and 1,292 reads were generated, respectively. We generated 3,703 ESTs from teliospores produced on the senescent primary wheat host. Finally, we generated 6,817 reads from haustoria isolated from infected wheat as well as 1,003 sequences from germinated urediniospores. Along with 25,558 previously generated ESTs, we compiled a database of 13,328 non-redundant sequences (4,506 singlets and 8,822 contigs. Fungal genes were predicted using the EST version of the self-training GeneMarkS algorithm. To refine the EST database, we compared EST sequences by BLASTN to a set of 454 pyrosequencing-generated contigs and Sanger BAC-end sequences derived both from the Pt genome, and to ESTs and genome reads from wheat. A collection of 6,308 fungal genes was identified and compared to sequences of the cereal rusts, Puccinia graminis f. sp. tritici (Pgt and stripe rust, P. striiformis f. sp

  6. Survival of Spores of Trichoderma longibrachiatum in Space: data from the Space Experiment SPORES on EXPOSE-R

    Science.gov (United States)

    Neuberger, Katja; Lux-Endrich, Astrid; Panitz, Corinna

    2015-01-01

    In the space experiment `Spores in artificial meteorites' (SPORES), spores of the fungus Trichoderma longibrachiatum were exposed to low-Earth orbit for nearly 2 years on board the EXPOSE-R facility outside of the International Space Station. The environmental conditions tested in space were: space vacuum at 10-7-10-4 Pa or argon atmosphere at 105 Pa as inert gas atmosphere, solar extraterrestrial ultraviolet (UV) radiation at λ > 110 nm or λ > 200 nm with fluences up to 5.8 × 108 J m-2, cosmic radiation of a total dose range from 225 to 320 mGy, and temperature fluctuations from -25 to +50°C, applied isolated or in combination. Comparable control experiments were performed on ground. After retrieval, viability of spores was analysed by two methods: (i) ethidium bromide staining and (ii) test of germination capability. About 30% of the spores in vacuum survived the space travel, if shielded against insolation. However, in most cases no significant decrease was observed for spores exposed in addition to the full spectrum of solar UV irradiation. As the spores were exposed in clusters, the outer layers of spores may have shielded the inner part. The results give some information about the likelihood of lithopanspermia, the natural transfer of micro-organisms between planets. In addition to the parameters of outer space, sojourn time in space seems to be one of the limiting parameters.

  7. 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.

  8. Germination and conjugation of Bacillus thuringiensis subsp. israelensis in the intestine of gnotobiotic rats

    DEFF Research Database (Denmark)

    Wilcks, Andrea; Ørum-Smidt, Lasse; Bahl, Martin Iain;

    2008-01-01

    Aims: To study the ability of Bacillus thuringiensis subsp. israelensis spores to germinate and subsequently transfer a conjugative plasmid in the intestinal tract of gnotobiotic rats. Methods and Results: Germination was studied by feeding germ-free rats with spores of a B. thuringiensis strain...... the conjugative plasmid pXO16 was introduced. Both strains were given as spores and transfer of pXO16 was observed from the donor to the recipient strain. Conclusions: Bacillus thuringiensis is able to have a full life cycle in the intestine of gnotobiotic rats including germination of spores, several cycles...... harbouring a plasmid encoding green fluorescent protein (GFP), which enabled quantification of germinated bacteria by flow cytometry. To study in vivo conjugation, germ-free rats were first associated with a B. thuringiensis recipient strain and after 1 week an isogenic donor strain harbouring...

  9. Molecular basis of early stages of Clostridium difficile infection: germination and colonization.

    Science.gov (United States)

    Sarker, Mahfuzur R; Paredes-Sabja, Daniel

    2012-08-01

    Clostridium difficile infections (CDIs) occur when antibiotic therapy disrupts the gastrointestinal flora, favoring infected C. difficile spores to germinate, outgrow, colonize and produce toxins. During CDI, C. difficile vegetative cells initiate the process of sporulation allowing a fraction of the spores to remain adhered to the intestinal surfaces. These spores, which are unaffected by antibiotic therapy commonly used for CDIs, then germinate, outgrow and recolonize the host's GI tract causing relapse of CDI. Consequently, the germination and colonization processes can be considered as the earliest and most essential steps for the development as well as relapse of CDI. The aim of this review is to provide an overview on the molecular basis involved in C. difficile spore germination and colonization.

  10. Spore-forming bacteria and their utilisation as probiotics.

    Science.gov (United States)

    Bader, J; Albin, A; Stahl, U

    2012-03-01

    In this review article, the beneficial application of bacterial spore formers as probiotics in the food industry is discussed based on the knowledge gleaned from current publications. The summary of new scientific results provides evidence of the advantages of the utilisation of Bacillus or Clostridium strains in the food industry. Both bacteria are able to produce a very stable duration form: the endospore. Compared to the widely used lactic acid bacteria, bacterial spores offer the advantage of a higher survival rate during the acidic stomach passage and better stability during the processing and storage of the food product. In many food products, germination of the spores does not occur. Hence the product quality of the food is not affected because of their inactive metabolism. Besides the possible utilisation and functional properties, an overview of the fast-developing knowledge about the mechanisms of the beneficial health effects of spore-forming bacteria is provided.

  11. Cryopreservation of fern spores

    Science.gov (United States)

    Spore banks for ferns are analogous to seed banks for angiosperms and provide a promising ex situ conservation tool because large quantities of germplasm with high genetic variation can be conserved in a small space with low economic and technical costs. Ferns produce two types of spores with very ...

  12. 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.

  13. Mushrooms as Rainmakers: How Spores Act as Nuclei for Raindrops.

    Science.gov (United States)

    Hassett, Maribeth O; Fischer, Mark W F; Money, Nicholas P

    2015-01-01

    Millions of tons of fungal spores are dispersed in the atmosphere every year. These living cells, along with plant spores and pollen grains, may act as nuclei for condensation of water in clouds. Basidiospores released by mushrooms form a significant proportion of these aerosols, particularly above tropical forests. Mushroom spores are discharged from gills by the rapid displacement of a droplet of fluid on the cell surface. This droplet is formed by the condensation of water on the spore surface stimulated by the secretion of mannitol and other hygroscopic sugars. This fluid is carried with the spore during discharge, but evaporates once the spore is airborne. Using environmental electron microscopy, we have demonstrated that droplets reform on spores in humid air. The kinetics of this process suggest that basidiospores are especially effective as nuclei for the formation of large water drops in clouds. Through this mechanism, mushroom spores may promote rainfall in ecosystems that support large populations of ectomycorrhizal and saprotrophic basidiomycetes. Our research heightens interest in the global significance of the fungi and raises additional concerns about the sustainability of forests that depend on heavy precipitation.

  14. Inhibition of Fungal Aflatoxin B1 Biosynthesis by Diverse Botanically ...

    African Journals Online (AJOL)

    effects on A. flavus growth and AFB1 production. Fungal spores were cultured ... Keywords: Polyphenols, Quercetin, Aflatoxin B1, Inhibition, Antioxidation. Tropical Journal of ..... agents used in animal feed or food processing areas. However,.

  15. Persistence strategies of Bacillus cereus spores isolated from dairy silo tanks.

    Science.gov (United States)

    Shaheen, Ranad; Svensson, Birgitta; Andersson, Maria A; Christiansson, Anders; Salkinoja-Salonen, Mirja

    2010-05-01

    Survival of Bacillus cereus spores of dairy silo tank origin was investigated under conditions simulating those in operational dairy silos. Twenty-three strains were selected to represent all B. cereus isolates (n = 457) with genotypes (RAPD-PCR) that frequently colonised the silo tanks of at least two of the sampled eight dairies. The spores were studied for survival when immersed in liquids used for cleaning-in-place (1.0% sodium hydroxide at pH 13.1, 75 degrees C; 0.9% nitric acid at pH 0.8, 65 degrees C), for adhesion onto nonliving surfaces at 4 degrees C and for germination and biofilm formation in milk. Four groups with different strategies for survival were identified. First, high survival (log 15 min kill steel from cold water. Third, a cereulide producing group with spores characterised by slow germination in rich medium and well preserved viability when exposed to heating at 90 degrees C. Fourth, spores capable of germinating at 8 degrees C and possessing the cspA gene. There were indications that spores highly resistant to hot 1% sodium hydroxide may be effectively inactivated by hot 0.9% nitric acid. Eight out of the 14 dairy silo tank isolates possessing hot-alkali resistant spores were capable of germinating and forming biofilm in whole milk, not previously reported for B. cereus.

  16. Splash : the dispersal of fungal plant pathogens in rain events

    NARCIS (Netherlands)

    Pielaat, A.

    2000-01-01

    Models were developed to study splash dispersal of fungal plant pathogens in space and time. The models incorporate the main mechanisms involved in splash dispersal, that is 1. A raindrop hits the thin water film on the crop surface containing spores and spores are dispersed in the splashing rain dr

  17. Ultraviolet irradiation of DNA complexed with. alpha. /. beta. -type small, acid-soluble proteins from spores of Bacillus or Clostridium species makes spore photoproduct but not thymine dimers

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, W.L.; Setlow, B.; Setlow, P. (Univ. of Connecticut Health Center, Farmington (United States))

    1991-10-01

    UV irradiation of complexes of DNA and an {alpha}/{beta}-type small, acid-soluble protein (SASP) from Bacillus subtilis spores gave decreasing amounts of pyrimidine dimers and increasing amounts of spore photoproduct as the SASP/DNA ratio was increased. The yields of pyrimidine dimers and spore photoproduct were < 0.2% and 8% of total thymine, respectively, when DNA saturated with SASP was irradiated at 254 nm with 30 kJ/m{sup 2}; in the absence of SASP the yields were reversed - 4.5% and 0.3%, respectively. Complexes of DNA with {alpha}/{beta}-type SASP from Bacillus cereus, Bacillus megaterium, or Clostridium bifermentans spores also gave spore photoproduct upon UV irradiation. However, incubation of these SASPs with DNA under conditions preventing complex formation or use of mutant SASPs that do not form complexes did not affect the photoproducts formed in vitro. These results suggest that the UV photochemistry of bacterial spore DNA in vivo is due to the binding of {alpha}/{beta}-type SASP, a binding that is known to cause a change in DNA conformation in vitro from the B form to the A form. The yields of spore photoproduct in vitro were significantly lower than in vivo, perhaps because of the presence of substances other than SASP in spores. It is suggested that as these factors diffuse out in the first minutes of spore germination, spore photoproduct yields become similar to those observed for irradiation of SASP/DNA complexes in vitro.

  18. Effects of endogenous D-alanine synthesis and autoinhibition of Bacillus anthracis germination on in vitro and in vivo infections.

    Science.gov (United States)

    McKevitt, Matthew T; Bryant, Katie M; Shakir, Salika M; Larabee, Jason L; Blanke, Steven R; Lovchik, Julie; Lyons, C Rick; Ballard, Jimmy D

    2007-12-01

    Bacillus anthracis transitions from a dormant spore to a vegetative bacillus through a series of structural and biochemical changes collectively referred to as germination. The timing of germination is important during early steps in infection and may determine if B. anthracis survives or succumbs to responsive macrophages. In the current study experiments determined the contribution of endogenous D-alanine production to the efficiency and timing of B. anthracis spore germination under in vitro and in vivo conditions. Racemase-mediated production of endogenous D-alanine by B. anthracis altered the kinetics for initiation of germination over a range of spore densities and exhibited a threshold effect wherein small changes in spore number resulted in major changes in germination efficiency. This threshold effect correlated with D-alanine production, was prevented by an alanine racemase inhibitor, and required L-alanine. Interestingly, endogenous production of inhibitory levels of D-alanine was detected under experimental conditions that did not support germination and in a germination-deficient mutant of B. anthracis. Racemase-dependent production of D-alanine enhanced survival of B. anthracis during interaction with murine macrophages, suggesting a role for inhibition of germination during interaction with these cells. Finally, in vivo experiments revealed an approximately twofold decrease in the 50% lethal dose of B. anthracis spores administered in the presence of D-alanine, indicating that rates of germination may be directly influenced by the levels of this amino acid during early stages of disease.

  19. Inhibition of Bacillus cereus spore outgrowth and multiplication by chitosan.

    Science.gov (United States)

    Mellegård, Hilde; From, Cecilie; Christensen, Bjørn E; Granum, Per E

    2011-10-03

    Bacillus cereus is an endospore-forming bacterium able to cause food-associated illness. Different treatment processes are used in the food industry to reduce the number of spores and thereby the potential of foodborne disease. Chitosan is a polysaccharide with well-documented antibacterial activity towards vegetative cells. The activity against bacterial spores, spore germination and subsequent outgrowth and growth (the latter two events hereafter denoted (out)growth), however, is poorly documented. By using six different chitosans with defined macromolecular properties, we evaluated the effect of chitosan on Bacillus cereus spore germination and (out)growth using optical density assays and a dipicolinic acid release assay. (Out)growth was inhibited by chitosan, but germination was not. The action of chitosan was found to be concentration-dependent and also closely related to weight average molecular weight (M(w)) and fraction of acetylation (F(A)) of the biopolymer. Chitosans of low acetylation (F(A)=0.01 or 0.16) inhibited (out)growth more effectively than higher acetylated chitosans (F(A)=0.48). For the F(A)=0.16 chitosans with medium (56.8kDa) and higher M(w) (98.3kDa), a better (out)growth inhibition was observed compared to low M(w) (10.6kDa) chitosan. The same trend was not evident with chitosans of 0.48 acetylation, where the difference in activity between the low (19.6kDa) and high M(w) (163.0kDa) chitosans was only minor. In a spore test concentration corresponding to 10(2)-10(3)CFU/ml (spore numbers relevant to food), less chitosan was needed to suppress (out)growth compared to higher spore numbers (equivalent to 10(8)CFU/ml), as expected. No major differences in chitosan susceptibility between three different strains of B. cereus were detected. Our results contribute to a better understanding of chitosan activity towards bacterial spore germination and (out)growth.

  20. Mass spectrometric study on inactivation mechanism of spore-forming bacteria by low-pressure surface-wave excited oxygen plasma

    Science.gov (United States)

    Zhao, Ying; Ogino, Akihisa; Nagatsu, Masaaki

    2011-05-01

    In this letter, the etching phenomena of the spore-forming bacteria by oxygen plasma were investigated by using quadrupole mass spectrometry. The etching by-products of H2O and CO2 were obviously detected during the oxygen plasma irradiation by the multiple ion detection measurement. Inactivation of roughly 106 spores population was achieved under almost the same reduced spore shapes for three different incident microwave powers. It is considered from the present results that the oxygen radical etching could cause damage to the germinant receptors located in the inner membrane inevitable for germination of spores, without any damage of the DNA in the cores.

  1. AM fungal exudates activate MAP kinases in plant cells in dependence from cytosolic Ca(2+) increase.

    Science.gov (United States)

    Francia, Doriana; Chiltz, Annick; Lo Schiavo, Fiorella; Pugin, Alain; Bonfante, Paola; Cardinale, Francesca

    2011-09-01

    The molecular dialogue occurring prior to direct contact between the fungal and plant partners of arbuscular-mycorrhizal (AM) symbioses begins with the release of fungal elicitors, so far only partially identified chemically, which can activate specific signaling pathways in the host plant. We show here that the activation of MAPK is also induced by exudates of germinating spores of Gigaspora margarita in cultured cells of the non-leguminous species tobacco (Nicotiana tabacum), as well as in those of the model legume Lotus japonicus. MAPK activity peaked about 15 min after the exposure of the host cells to the fungal exudates (FE). FE were also responsible for a rapid and transient increase in free cytosolic Ca(2+) in Nicotiana plumbaginifolia and tobacco cells, and pre-treatment with a Ca(2+)-channel blocker (La(3+)) showed that in these cells, MAPK activation was dependent on the cytosolic Ca(2+) increase. A partial dependence of MAPK activity on the common Sym pathway could be demonstrated for a cell line of L. japonicus defective for LjSym4 and hence unable to establish an AM symbiosis. Our results show that MAPK activation is triggered by an FE-induced cytosolic Ca(2+) transient, and that a Sym genetic determinant acts to modulate the intensity and duration of this activity.

  2. Rapid inactivation of Penicillium digitatum spores using high-density nonequilibrium atmospheric pressure plasma

    Science.gov (United States)

    Iseki, Sachiko; Ohta, Takayuki; Aomatsu, Akiyoshi; Ito, Masafumi; Kano, Hiroyuki; Higashijima, Yasuhiro; Hori, Masaru

    2010-04-01

    A promising, environmentally safe method for inactivating fungal spores of Penicillium digitatum, a difficult-to-inactivate food spoilage microorganism, was developed using a high-density nonequilibrium atmospheric pressure plasma (NEAPP). The NEAPP employing Ar gas had a high electron density on the order of 1015 cm-3. The spores were successfully and rapidly inactivated using the NEAPP, with a decimal reduction time in spores (D value) of 1.7 min. The contributions of ozone and UV radiation on the inactivation of the spores were evaluated and concluded to be not dominant, which was fundamentally different from the conventional sterilizations.

  3. Spore formation and toxin production in Clostridium difficile biofilms.

    Directory of Open Access Journals (Sweden)

    Ekaterina G Semenyuk

    Full Text Available The ability to grow as a biofilm can facilitate survival of bacteria in the environment and promote infection. To better characterize biofilm formation in the pathogen Clostridium difficile, we established a colony biofilm culture method for this organism on a polycarbonate filter, and analyzed the matrix and the cells in biofilms from a variety of clinical isolates over several days of biofilm culture. We found that biofilms readily formed in all strains analyzed, and that spores were abundant within about 6 days. We also found that extracellular DNA (eDNA, polysaccharide and protein was readily detected in the matrix of all strains, including the major toxins A and/or B, in toxigenic strains. All the strains we analyzed formed spores. Apart from strains 630 and VPI10463, which sporulated in the biofilm at relatively low frequencies, the frequencies of biofilm sporulation varied between 46 and 65%, suggesting that variations in sporulation levels among strains is unlikely to be a major factor in variation in the severity of disease. Spores in biofilms also had reduced germination efficiency compared to spores obtained by a conventional sporulation protocol. Transmission electron microscopy revealed that in 3 day-old biofilms, the outermost structure of the spore is a lightly staining coat. However, after 6 days, material that resembles cell debris in the matrix surrounds the spore, and darkly staining granules are closely associated with the spores surface. In 14 day-old biofilms, relatively few spores are surrounded by the apparent cell debris, and the surface-associated granules are present at higher density at the coat surface. Finally, we showed that biofilm cells possess 100-fold greater resistance to the antibiotic metronidazole then do cells cultured in liquid media. Taken together, our data suggest that C. difficile cells and spores in biofilms have specialized properties that may facilitate infection.

  4. Spore formation and toxin production in Clostridium difficile biofilms.

    Science.gov (United States)

    Semenyuk, Ekaterina G; Laning, Michelle L; Foley, Jennifer; Johnston, Pehga F; Knight, Katherine L; Gerding, Dale N; Driks, Adam

    2014-01-01

    The ability to grow as a biofilm can facilitate survival of bacteria in the environment and promote infection. To better characterize biofilm formation in the pathogen Clostridium difficile, we established a colony biofilm culture method for this organism on a polycarbonate filter, and analyzed the matrix and the cells in biofilms from a variety of clinical isolates over several days of biofilm culture. We found that biofilms readily formed in all strains analyzed, and that spores were abundant within about 6 days. We also found that extracellular DNA (eDNA), polysaccharide and protein was readily detected in the matrix of all strains, including the major toxins A and/or B, in toxigenic strains. All the strains we analyzed formed spores. Apart from strains 630 and VPI10463, which sporulated in the biofilm at relatively low frequencies, the frequencies of biofilm sporulation varied between 46 and 65%, suggesting that variations in sporulation levels among strains is unlikely to be a major factor in variation in the severity of disease. Spores in biofilms also had reduced germination efficiency compared to spores obtained by a conventional sporulation protocol. Transmission electron microscopy revealed that in 3 day-old biofilms, the outermost structure of the spore is a lightly staining coat. However, after 6 days, material that resembles cell debris in the matrix surrounds the spore, and darkly staining granules are closely associated with the spores surface. In 14 day-old biofilms, relatively few spores are surrounded by the apparent cell debris, and the surface-associated granules are present at higher density at the coat surface. Finally, we showed that biofilm cells possess 100-fold greater resistance to the antibiotic metronidazole then do cells cultured in liquid media. Taken together, our data suggest that C. difficile cells and spores in biofilms have specialized properties that may facilitate infection.

  5. Toward a Noninvasive, Label-Free Screening Method for Determining Spore Inoculum Quality of Penicillium chrysogenum Using Raman Spectroscopy.

    Science.gov (United States)

    Wieland, Karin; Kuligowski, Julia; Ehgartner, Daniela; Ramer, Georg; Koch, Cosima; Ofner, Johannes; Herwig, Christoph; Lendl, Bernhard

    2017-01-01

    We report on a label-free, noninvasive method for determination of spore inoculum quality of Penicillium chrysogenum prior to cultivation/germination. Raman microspectroscopy providing direct, molecule-specific information was used to extract information on the viability state of spores sampled directly from the spore inoculum. Based on the recorded Raman spectra, a supervised classification method was established for classification between living and dead spores and thus determining spore inoculum quality for optimized process control. A fast and simple sample preparation method consisting of one single dilution step was employed to eliminate interfering signals from the matrix and to achieve isolation of single spores on the sample carrier (CaF2). Aiming to avoid any influence of the killing procedure in the Raman spectrum of the spore, spores were considered naturally dead after more than one year of storage time. Fluorescence staining was used as reference method. A partial least squares discriminant analysis classifier was trained with Raman spectra of 258 living and dead spores (178 spectra for calibration, 80 spectra for validation). The classifier showed good performance when being applied to a 1 µL droplet taken from a 1:1 mixture of living and dead spores. Of 135 recorded spectra, 51% were assigned to living spores while 49% were identified as dead spores by the classifier. The results obtained in this work are a fundamental step towards developing an automated, label-free, and noninvasive screening method for assessing spore inoculum quality.

  6. Carbon-13 (13C) labeling of Bacillus subtilis vegetative cells and spores: suitability for DNA stable isotope probing (DNA-SIP) of spores in soils.

    Science.gov (United States)

    Nicholson, Wayne L; Fedenko, Jeffrey; Schuerger, Andrew C

    2009-07-01

    To test the suitability of DNA stable isotope probing (DNA-SIP) for characterizing bacterial spore populations in soils, the properties of Bacillus subtilis cells and spores intensely labeled with [(13)C]glucose were characterized. Spore germination, vegetative growth rates, and sporulation efficiency were indistinguishable on glucose versus [(13)C]glucose, as were spore wet heat and UV resistance. Unlabeled and (13)C-labeled spores contained 1.0989 and 74.336 at.% (13)C, and exhibited wet densities of 1.356 and 1.365 g/ml, respectively. Chromosomal DNAs containing (12)C versus (13)C were readily separated by their different buoyant densities in cesium chloride/ethidium bromide gradients.

  7. 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.

    Science.gov (United States)

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

    2011-04-01

    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 possible intoxication. Similar issues though more pending toward spore toxigenicity are observed for the anaerobic Clostridia. The paper indicates the nature of stress resistance and highlights contemporary molecular approaches to analyze the mechanistic basis of it in Bacilli. A molecular comparison between a laboratory strain and a food borne isolate, very similar at the genomic level to the laboratory strain but generating extremely heat resistant spores, is discussed. The approaches cover genome-wide genotyping, proteomics and genome-wide expression analyses studies. The analyses aim at gathering sufficient molecular information to be able to put together an initial framework for dynamic modelling of spore germination and outgrowth behaviour. Such emerging models should be developed both at the population and at the single spore level. Tools and challenges in achieving the latter are succinctly discussed.

  8. Fungal arthritis

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000444.htm Fungal arthritis To use the sharing features on this page, please enable JavaScript. Fungal arthritis is swelling and irritation (inflammation) of a joint ...

  9. Fungal Meningitis

    Science.gov (United States)

    ... Schedules Preteen & Teen Vaccines Meningococcal Disease Sepsis Fungal Meningitis Language: English Español (Spanish) Recommend on Facebook Tweet ... the brain or spinal cord. Investigation of Fungal Meningitis, 2012 In September 2012, the Centers for Disease ...

  10. Fed-batch production of gluconic acid by terpene-treated Aspergillus niger spores.

    Science.gov (United States)

    Ramachandran, Sumitra; Fontanille, Pierre; Pandey, Ashok; Larroche, Christian

    2008-12-01

    Aspergillus niger spores were used as catalyst in the bioconversion of glucose to gluconic acid. Spores produced by solid-state fermentation were treated with 15 different terpenes including monoterpenes and monoterpenoids to permeabilize and inhibit spore germination. It was found that spore membrane permeability is significantly increased by treatment with terpenoids when compared to monoterpenes. Best results were obtained with citral and isonovalal. Studies were carried out to optimize spores concentration (10(7)-10(10) spores/mL), terpene concentrations in the bioconversion medium and time of exposure (1-18 h) needed for permeabilization of spores. Fed-batch production of gluconate was done in a bioreactor with the best conditions [10(9) spores/mL of freeze-thawed spores treated with citral (3% v/v) for 5 h] followed by sequential additions of glucose powder and pH-regulated with a solution containing 2 mol/L of either NaOH or KOH. Bioconversion performance of the spore enzyme was compared with the commercial glucose oxidase at 50, 60, and 70 degrees C. Results showed that the spore enzyme was comparatively stable at 60 degrees C. It was also found that the spores could be reutilized for more than 14 cycles with almost similar reaction rate. Similar biocatalytic activity was rendered by spores even after its storage of 1 year at -20 degrees C. This study provided an experimental evidence of the significant catalytic role played by A. niger spore in bioconversion of glucose to gluconic acid with high yield and stability, giving protection to glucose oxidase.

  11. Effects of copper on germination, growth and sporulation of Clostridium tyrobutyricum.

    Science.gov (United States)

    Mato Rodriguez, L; Alatossava, T

    2010-05-01

    The effects of copper (Cu(2+)) on spore germination, vegetative growth and sporulation of Clostridium tyrobutyricum, which is capable to causing texture and flavour defects in Emmental cheese, were studied. Spore suspensions of three different strains were used as starting material for two experimental set-ups. The first studied the effects of supplemented (0-30 ppm) copper in RCM medium during spore germination and vegetative growth of C. tyrobutyricum measured by plating. The second set-up studied the effects of copper (0-30 ppm) in RCM medium during growth and sporulation of C. tyrobutyricum as measured by optical density at 550 nm and by platings after heat treatment of the samples respectively. Inhibition of germination, vegetative growth and sporulation processes by copper was strain-dependent. Both sporulation and germination were more sensitive than vegetative growth of C. tyrobutyricum to the inhibitory effects of copper. Copper, at the concentrations investigated in this study, inhibits spore germination of C. tyrobutyricum strains. Consequently copper may reduce the risk of late blowing spoilage from in the germination of C. tyrobutyricum spores during the ripening period of Emmental cheese.

  12. Application of X-ray microscopy in food science investigation of high pressure affected bacterial spores

    Science.gov (United States)

    Mönch, Susanne; Heinz, Volker; Guttmann, Peter; Knorr, Dietrich

    2000-05-01

    Using the Göttingen transmission X-ray microscope at BESSY the effect of different pressure and temperature levels during the high hydrostatic pressure (HP) treatment was investigated. At 150 MPa and temperatures up to 50 °C the triggering of germination was observed by standard microbiological methods with Bacillus subtilis spores. Increasing the temperature to 70 °C at the same pressure level killed the spores without any indication of germination. By X-ray microscopy images it could be shown that the typical disintegration of the protoplast is inhibited. This suggests that the enzymic reaction pathway is possibly affected under specific pressure temperature conditions.

  13. 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.

  14. 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.

  15. 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

    with 37 deg. C, and then dual stained with the fluorescent dyes SYTO 16 and propidium iodide. For pressure treated spores four distinct populations were detected by flow cytometry, and for these we suggest a three step model of inactivation involving a germination step following hydrolysis of the spore cortex, an unknown step, and finally an inactivation step with physical compromise of the spore inner membrane. An understanding of these effects and mechanisms will aid the safety assessment of pressure assisted thermal sterilisation, in turn facilitating the adoption by industry and commercialisation of such processes.

  16. New pressure and temperature effects on bacterial spores

    Science.gov (United States)

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

    2008-07-01

    C, and then dual stained with the fluorescent dyes SYTO 16 and propidium iodide. For pressure treated spores four distinct populations were detected by flow cytometry, and for these we suggest a three step model of inactivation involving a germination step following hydrolysis of the spore cortex, an unknown step, and finally an inactivation step with physical compromise of the spore inner membrane. An understanding of these effects and mechanisms will aid the safety assessment of pressure assisted thermal sterilisation, in turn facilitating the adoption by industry and commercialisation of such processes.

  17. 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.

  18. Transcriptional analysis of temporal gene expression in germinating Clostridium difficile 630 endospores.

    Directory of Open Access Journals (Sweden)

    Marcin Dembek

    Full Text Available Clostridium difficile is the leading cause of hospital acquired diarrhoea in industrialised countries. Under conditions that are not favourable for growth, the pathogen produces metabolically dormant endospores via asymmetric cell division. These are extremely resistant to both chemical and physical stress and provide the mechanism by which C. difficile can evade the potentially fatal consequences of exposure to heat, oxygen, alcohol, and certain disinfectants. Spores are the primary infective agent and must germinate to allow for vegetative cell growth and toxin production. While spore germination in Bacillus is well understood, little is known about C. difficile germination and outgrowth. Here we use genome-wide transcriptional analysis to elucidate the temporal gene expression patterns in C. difficile 630 endospore germination. We have optimized methods for large scale production and purification of spores. The germination characteristics of purified spores have been characterized and RNA extraction protocols have been optimized. Gene expression was highly dynamic during germination and outgrowth, and was found to involve a large number of genes. Using this genome-wide, microarray approach we have identified 511 genes that are significantly up- or down-regulated during C. difficile germination (p≤0.01. A number of functional groups of genes appeared to be co-regulated. These included transport, protein synthesis and secretion, motility and chemotaxis as well as cell wall biogenesis. These data give insight into how C. difficile re-establishes its metabolism, re-builds the basic structures of the vegetative cell and resumes growth.

  19. On the origin of heterogeneity in (preservation) resistance of Bacillus spores: Input for a ‘systems’ analysis approach of bacterial spore outgrowth

    NARCIS (Netherlands)

    Hornstra, L.M.; ter Beek, A.; Smelt, J.P.; Kallemeijn, W.W.; Brul, S.

    2009-01-01

    Bacterial spores are the ultimate (stress) ‘survival capsules’. They allow strains from the Bacillus and Clostridium species to survive harsh environmental conditions. In addition to the decision to enter sporulation the decision to do the reverse (germinate) is also a decisive event after which the

  20. The effects of meteorological factors on the occurrence of Ganoderma sp. spores in the air

    Science.gov (United States)

    Grinn-Gofroń, Agnieszka; Strzelczak, Agnieszka

    2011-03-01

    Ganoderma sp. is an airborne fungal spore type known to trigger respiratory allergy symptoms in sensitive patients. Aiming to reduce the risk for allergic individuals, we analysed fungal spore circulation in Szczecin, Poland, and its dependence on meteorological conditions. Statistical models for the airborne spore concentrations of Ganoderma sp.—one of the most abundant fungal taxa in the area—were developed. Aerobiological sampling was conducted over 2004-2008 using a volumetric 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 temperatures. These data were used as the explaining variables. Due to the non-linearity and non-normality of the data set, the applied modelling techniques were artificial neural networks (ANN) and mutlivariate regression trees (MRT). The obtained classification and MRT models predicted threshold conditions above which Ganoderma sp. appeared in the air. It turned out that dew point temperature was the main factor influencing the presence or absence of Ganoderma sp. spores. Further analysis of spore seasons revealed that the airborne fungal spore concentration depended only slightly on meteorological factors.

  1. The role of wild boars in spore dispersal of hypogeous fungi

    Directory of Open Access Journals (Sweden)

    Federica Piattoni

    2013-12-01

    Full Text Available Wild boars (Sus scrofa L. are well-known for soil disturbance in natural and cultivated truffières but their role in spore dispersal is poorly investigated. In the present work we studied the occurrence of hypogeous fungal spores in faecal contents of 14 wild boars randomly hunted in “Parco dei Gessi e Calanchi dell’Abbadessa” Regional Park (North of Italy where truffle production has been previously investigated for three years. Six methods for spore analysis in faeces were compared and the suspension of faeces in ZnSO4 (70% solution resulted to be the most reliable. Hypogeous fungal spores, including Tuber magnatum and Tuber aestivum spores, were detected in 9 animals. This result suggests that the detection of fungal spores in faeces of wild boars may provide information on the presence of hypogeous fungi in an area. However, the poor abundance of spores suggests that the wild boar can be considered an opportunistic mycophagist, ingesting truffles only occasionally, as a seasonal source of food. Considering the magnitude of wild boar movements during seasonal migrations, it is possible to speculate that they play a key role in truffle long distance dispersal.

  2. Anthrax Spores under a microscope

    Science.gov (United States)

    2003-01-01

    Anthrax spores are inactive forms of Bacillus anthracis. They can survive for decades inside a spore's tough protective coating; they become active when inhaled by humans. A result of NASA- and industry-sponsored research to develop small greenhouses for space research is the unique AiroCide TiO2 system that kills anthrax spores and other pathogens.

  3. 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.

  4. Effect of surfactants and temperature on germination and vegetative growth of Beauveria bassiana.

    Science.gov (United States)

    Mwamburi, Lizzy A; Laing, Mark D; Miller, Ray M

    2015-03-01

    Three non-ionic surfactants: Tween20, Tween80 and Breakthru (®) were screened for their effects on spore germination and mycelial growth rates and for their influence on three isolates of Beauveria bassiana spore germination at various temperatures. Tween20 and Tween80 were compatible with all the B. bassiana isolates in the germination studies, but inhibited germination at higher surfactant concentrations, irrespective of the conidial concentrations . Breakthru (®) had an inhibitory effect on germination even at the lowest concentration of 0.1% on all the B. bassiana isolates. The effects of the surfactants on spore germination did not correspond with their effects on colony growth. Conidial viability within the same formulation declined significantly with increases in temperature, irrespective of the surfactant. The optimal temperature for conidial germination of B. bassiana isolates was approximately 25 °C with an upper limit at 30 °C. Isolate 7320 was identified as the least affected by the different surfactants. This isolate was able to germinate rapidly in a broad temperature range of 25-30 °C after 24 h, this characteristic being an essential factor in controlling house fly populations in poultry houses.

  5. Efectividad del Acido Peracético sobre la reducción de la carga de Esporas de Mohos causantes de Pudrición Poscosecha de Frutas y Hortalizas Effectiveness of Peracetic Acid on fungal Spores reduction of Moulds causing rotting in Fruits and Vegetables

    Directory of Open Access Journals (Sweden)

    María V Kyanko

    2010-01-01

    Full Text Available Se evaluó in vitro la efectividad del ácido peracético sobre la reducción de la carga de esporas de mohos micotoxicogénicos causantes de pudrición de frutas y hortalizas, para determinar su potencial aplicación al control poscosecha de esta patología. Se evaluó tres concentraciones de ácido (0.05%, 0.1 % y 0.3% para determinar su capacidad antifúngica frente a Alternaria alternata, Fusarium graminearum, Aspergillus ochraceus, A. níger, A. flavus, Penicillium roqueforti y P. expansum. Se observó una reducción de la carga de esporas aún a la más baja concentración ensayada, efecto que incrementó con el aumento de la concentración del tratamiento. A una concentración del 0.3 % se logró una mucho mayor reducción de la carga de esporas viables de A. alternata, F. graminearum y A. ochraceus, respectivamente. El ácido peracético podría resultar una alternativa de tratamiento no contaminante para el control poscosecha de la pudrición fúngica.The objective of this work was to determine in vitro the effectiveness of peracetic acid on the load reduction of mould spores that are responsible for rotting in fruits and vegetables to evaluate its potential application to post-harvest control. Three concentrations of peracetic acid (0.05%, 0.1% and 0.3% were used to evaluate its anti-fungal capacity against Alternaria Alternata, Fusarium graminearum, Aspergillus ochraceus, A. niger, A. flavus, Penicillium roqueforti and P. expansum. It was observed reduction of the load of spores using the lowest concentration. This effect was increased with a higher concentration of peracetic acid. It was extremely effective at a concentration of 0.3% against A. alternata, F. graminearum and A. ochraceus. It is concluded that the peracetic acid is a nonpolluting alternative treatment for post-harvest rotting control of fruits and vegetables

  6. Mechanisms of Bacterial Spore Germination and Its Heterogeneity

    Science.gov (United States)

    2015-01-10

    Clostridium difficile ribotype 027 in Chile , Emerging Infectious isease, (08 2012): 1370. doi: Arturo Ramirez-Peralta, Srishti Gupta, Xuan Yi Butzin...Molecular Biology, (09 2010): . doi: Lingbo Kong, Peter Setlow, Yong-qing Li. Direct analysis of water content and movement in single dormant bacterial... Students Received Book TOTAL: Received Book Chapter TOTAL: PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number: Discipline John Sekar 1.00 Robert Sheehan

  7. Do small spores disperse further than large spores?

    Science.gov (United States)

    Norros, Veera; Rannik, Ullar; Hussein, Tareq; Petäjä, Tuukka; Vesala, Timo; Ovaskainen, Otso

    2014-06-01

    In species that disperse by airborne propagules an inverse relationship is often assumed between propagule size and dispersal distance. However, for microscopic spores the evidence for the relationship remains ambiguous. Lagrangian stochastic dispersion models that have been successful in predicting seed dispersal appear to predict similar dispersal for all spore sizes up to -40 microm diameter. However, these models have assumed that spore size affects only the downwards drift of particles due to gravitation and have largely omitted the highly size-sensitive deposition process to surfaces such as forest canopy. On the other hand, they have assumed that spores are certain to deposit when the air parcel carrying them touches the ground. Here, we supplement a Lagrangian stochastic dispersion model with a mechanistic deposition model parameterized by empirical deposition data for 1-10 microm spores. The inclusion of realistic deposition improved the ability of the model to predict empirical data on the dispersal of a wood-decay fungus (aerodynamic spore size 3.8 microm). Our model predicts that the dispersal of 1-10 microm spores is in fact highly sensitive to spore size, with 97-98% of 1 microm spores but only 12-58% of 10-microm spores dispersing beyond 2 km in the simulated range of wind and canopy conditions. Further, excluding the assumption of certain deposition at the ground greatly increased the expected dispersal distances throughout the studied spore size range. Our results suggest that by evolutionary adjustment of spore size, release height and timing of release, fungi and other organisms with microscopic spores can change the expected distribution of dispersal locations markedly. The complex interplay of wind and canopy conditions in determining deposition resulted in some counterintuitive predictions, such as that spores disperse furthest under intermediate wind, providing intriguing hypotheses to be tested empirically in future studies.

  8. [Fungal keratitis].

    Science.gov (United States)

    Bourcier, T; Sauer, A; Letscher-Bru, V; Candolfi, E

    2011-10-01

    Fungal keratitis (keratomycosis) is a rare but severe cause of infectious keratitis. Its incidence is constant, due to steroids or immunosuppressive treatments and contact lenses. Pathogens often invade corneas with chronic diseases of the ocular surface but fungal keratitis is also observed following injuries with plant foreign objects. The poor prognosis of these infections is related both to fungal virulence, decreased host defense, as well as delays in diagnosis. However, new antimycotic treatments allow better management and prognosis.

  9. Semi-automated bacterial spore detection system with micro-fluidic chips for aerosol collection, spore treatment and ICAN DNA detection.

    Science.gov (United States)

    Inami, Hisao; Tsuge, Kouichiro; Matsuzawa, Mitsuhiro; Sasaki, Yasuhiko; Togashi, Shigenori; Komano, Asuka; Seto, Yasuo

    2009-07-15

    A semi-automated bacterial spore detection system (BSDS) was developed to detect biological threat agents (e.g., Bacillus anthracis) on-site. The system comprised an aerosol sampler, micro-fluidic chip-A (for spore germination and cell lysis), micro-fluidic chip-B (for extraction and detection of genomic DNA) and an analyzer. An aerosol with bacterial spores was first collected in the collection chamber of chip-A with a velocity of 300 l/min, and the chip-A was taken off from the aerosol sampler and loaded into the analyzer. Reagents packaged in the chip-A were sequentially applied into the chamber. The genomic DNA extract from spore lyzate was manually transferred from chip-A to chip-B and loaded into the analyzer. Genomic DNA in chip-B was first trapped on a glass bead column, washed with various reagents, and eluted to the detection chamber by sequential auto-dispensing. Isothermal and chimeric primer-initiated amplification of nucleic acids (ICAN) with fluorescent measurement was adopted to amplify and detect target DNA. Bacillus subtilis was the stimulant of biological warfare agent in this experiment. Pretreatment conditions were optimized by examining bacterial target DNA recovery in the respective steps (aerosol collection, spore germination, cell lysis, and DNA extraction), by an off-chip experiment using a real-time polymerase chain reaction quantification method. Without the germination step, B. subtilis spores did not demonstrate amplification of target DNA. The detection of 10(4) spores was achieved within 2h throughout the micro-fluidic process.

  10. Production of nitric oxide using a microwave plasma torch and its application to fungal cell differentiation

    Science.gov (United States)

    Na, Young Ho; Kumar, Naresh; Kang, Min-Ho; Cho, Guang Sup; Choi, Eun Ha; Park, Gyungsoon; Uhm, Han Sup

    2015-03-01

    The generation of nitric oxide by a microwave plasma torch is proposed for its application to cell differentiation. A microwave plasma torch was developed based on basic kinetic theory. The analytical theory indicates that nitric oxide density is nearly proportional to oxygen molecular density and that the high-temperature flame is an effective means of generating nitric oxide. Experimental data pertaining to nitric oxide production are presented in terms of the oxygen input in units of cubic centimeters per minute. The apparent length of the torch flame increases as the oxygen input increases. The various levels of nitric oxide are observed depending on the flow rate of nitrogen gas, the mole fraction of oxygen gas, and the microwave power. In order to evaluate the potential of nitric oxide as an activator of cell differentiation, we applied nitric oxide generated from the microwave plasma torch to a model microbial cell (Neurospora crassa: non-pathogenic fungus). Germination and hyphal differentiation of fungal cells were not dramatically changed but there was a significant increase in spore formation after treatment with nitric oxide. In addition, the expression level of a sporulation related gene acon-3 was significantly elevated after 24 h upon nitric oxide treatment. Increase in the level of nitric oxide, nitrite and nitrate in water after nitric oxide treatment seems to be responsible for activation of fungal sporulation. Our results suggest that nitric oxide generated by plasma can be used as a possible activator of cell differentiation and development.

  11. Control of Clostridium perfringens spores by plant-derived antimicrobials during cooling of cooked ground beef

    Science.gov (United States)

    Inhibition of Clostridium perfringens spore germination and outgrowth by carvacrol, cinnamaldehyde, thymol, oregano oil and two green tea extracts with low (green tea leaf powder (GTL); 141 mg of total catechins/g of green tea extract) and high (green tea leaf extract (GTE); 697 mg of total catechin...

  12. The effect of turf cutting on plant and arbuscular mycorrhizal spore recolonisation: Implications for heathland restoration

    NARCIS (Netherlands)

    Vergeer, P.; Berg, van den L.J.L.; Baar, J.; Ouborg, N.J.; Roelofs, J.G.M.

    2006-01-01

    In two natural heathland vegetations, we analysed the effect of turf cutting on spore numbers of arbuscular mycorrhizal fungi (AMF). Next to this, we performed a controlled factorial experiment to examine the role of AMF for germination and establishment of Arnica montana in both turf cut and non-tu

  13. Comparative analysis of Bacillus weihenstephanensis KBAB4 spores obtained at different temperatures

    NARCIS (Netherlands)

    Garcia, D.; Voort, van der M.; Abee, T.

    2010-01-01

    The impact of Bacillus weihenstephanensis KBAB4 sporulation temperature history was assessed on spore heat resistance, germination and outgrowth capacity at a temperature range from 7 to 30 °C. Sporulation rate and efficiency decreased at low temperature, as cells sporulated at 12, 20 and 30 °C with

  14. 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.

  15. Fungal endophytes characterization from four species of Diplazium Swartz

    Science.gov (United States)

    Affina-Eliya, A. A.; Noraini, T.; Nazlina, I.; Ruzi, A. R.

    2014-09-01

    Four species on genus Diplazium namely Diplazium tomentosum, D. sorzogonense, D. asperum and D. accedens of Peninsular Malaysia were studied for presence of fungal endophyte. The objective of this study is to characterize fungal endophytes in the rhizome of four Diplazium species. The rhizome was surface sterilized and incubated to isolate fungal endophytes. Characterization of the colonies was performed by macroscopic morphological, microscopic identification, types of hyphae and mycelium, and spore structure. For isolation that produces spores, the structure of conidiophores and conidia were identified. From this study, four fungal have been isolated and determined as Aspergillus sp. (isolates AE 1), Aspergillus fumigatus (isolates AE 2), Aspergillus versicolor (isolates AE 3) and Verticillium sp. (isolates AE 4). The fungal isolates from this study were classified from the same family Moniliaceae.

  16. New Rapid Spore Assay

    Science.gov (United States)

    Kminek, Gerhard; Conley, Catharine

    2012-07-01

    The presentation will detail approved Planetary Protection specifications for the Rapid Spore Assay for spacecraft components and subsystems. Outlined will be the research and studies on which the specifications were based. The research, funded by ESA and NASA/JPL, was conducted over a period of two years and was followed by limited cleanroom studies to assess the feasibility of this assay during spacecraft assembly.

  17. Identification of CdnL, a Putative Transcriptional Regulator Involved in Repair and Outgrowth of Heat-Damaged Bacillus cereus Spores.

    Directory of Open Access Journals (Sweden)

    Alicja K Warda

    Full Text Available Spores are widely present in the environment and are common contaminants in the food chain, creating a challenge for food industry. Nowadays, heat treatments conventionally applied in food processing may become milder to comply with consumer desire for products with higher sensory and nutritional values. Consequently subpopulations of spores may emerge that are sublethally damaged rather than inactivated. Such spores may germinate, repair damage, and eventually grow out leading to uncontrolled spoilage and safety issues. To gain insight into both the behaviour of damaged Bacillus cereus spores, and the process of damage repair, we assessed the germination and outgrowth performance using OD595 measurements and microscopy combined with genome-wide transcription analysis of untreated and heat-treated spores. The first two methods showed delayed germination and outgrowth of heat-damaged B. cereus ATCC14579 spores. A subset of genes uniquely expressed in heat-treated spores was identified with putative roles in the outgrowth of damaged spores, including cdnL (BC4714 encoding the putative transcriptional regulator CdnL. Next, a B. cereus ATCC14579 cdnL (BC4714 deletion mutant was constructed and assessment of outgrowth from heat-treated spores under food relevant conditions showed increased damage compared to wild type spores. The approach used in this study allows for identification of candidate genes involved in spore damage repair. Further identification of cellular parameters and characterisation of the molecular processes contributing to spore damage repair may provide leads for better control of spore outgrowth in foods.

  18. Morphogenesis is coordinated with nuclear division in germinating Aspergillus nidulans conidiospores.

    Science.gov (United States)

    Harris, S D

    1999-10-01

    Germinating Aspergillus nidulans conidiospores switch to polarized apical growth following an initial period of isotropic expansion. At the same time, they re-enter the nuclear division cycle. The relationship between spore polarization and nuclear division was investigated by testing the effect of cell cycle inhibitors and temperature-sensitive cell cycle mutations on spore morphogenesis. On rich media, it was found that spore polarization is delayed if completion of the first mitosis is blocked. The observed delay may be dependent upon the activity of the mitosis-promoting NIMA kinase. An additional mechanism appears to prevent polarization as the spore progresses through its first S phase. In contrast, on poor media, spore polarization does not require completion of the first mitosis. These observations suggest that spore morphogenesis is influenced by cell cycle signals in a growth-dependent manner.

  19. Clostridium difficile spore-macrophage interactions: spore survival.

    Directory of Open Access Journals (Sweden)

    Daniel Paredes-Sabja

    Full Text Available BACKGROUND: Clostridium difficile is the main cause of nosocomial infections including antibiotic associated diarrhea, pseudomembranous colitis and toxic megacolon. During the course of Clostridium difficile infections (CDI, C. difficile undergoes sporulation and releases spores to the colonic environment. The elevated relapse rates of CDI suggest that C. difficile spores has a mechanism(s to efficiently persist in the host colonic environment. METHODOLOGY/PRINCIPAL FINDINGS: In this work, we provide evidence that C. difficile spores are well suited to survive the host's innate immune system. Electron microscopy results show that C. difficile spores are recognized by discrete patchy regions on the surface of macrophage Raw 264.7 cells, and phagocytosis was actin polymerization dependent. Fluorescence microscopy results show that >80% of Raw 264.7 cells had at least one C. difficile spore adhered, and that ∼60% of C. difficile spores were phagocytosed by Raw 264.7 cells. Strikingly, presence of complement decreased Raw 264.7 cells' ability to phagocytose C. difficile spores. Due to the ability of C. difficile spores to remain dormant inside Raw 264.7 cells, they were able to survive up to 72 h of macrophage infection. Interestingly, transmission electron micrographs showed interactions between the surface proteins of C. difficile spores and the phagosome membrane of Raw 264.7 cells. In addition, infection of Raw 264.7 cells with C. difficile spores for 48 h produced significant Raw 264.7 cell death as demonstrated by trypan blue assay, and nuclei staining by ethidium homodimer-1. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that despite efficient recognition and phagocytosis of C. difficile spores by Raw 264.7 cells, spores remain dormant and are able to survive and produce cytotoxic effects on Raw 264.7 cells.

  20. Quantification of the impact of single and multiple mild stresses on outgrowth heterogeneity of Bacillus cereus spores.

    Science.gov (United States)

    van Melis, C C J; den Besten, H M W; Nierop Groot, M N; Abee, T

    2014-05-02

    Outgrowth heterogeneity of bacterial spore populations complicates both prediction and efficient control of spore outgrowth. In this study, the impact of mild preservation stresses on outgrowth of Bacillus cereus ATCC 14579 spores was quantified during the first stages of outgrowth. Heterogeneity in outgrowth of heat-treated (90°C for 10 min) and non-heat-treated germinated single spores to the maximum micro-colony stage of 256 cells was assessed by direct imaging on Anopore strips, placed on BHI plates at pH7 and pH5.5, without and with added NaCl or sorbic acid (HSA). At pH7 non-heated and heat-treated germinated spores required 6h to reach the maximum microcolony stage with limited heterogeneity, and these parameters were only slightly affected with both types of spores when incubated at pH7 with added NaCl. Notably, the most pronounced effects were observed during outgrowth of spores at pH5.5 without and with added NaCl or HSA. Non-heat-treated germinated spores showed again efficient outgrowth with limited heterogeneity reaching the maximum microcolony stage after 6h at pH5.5, which increased to 12h and 16 h with added NaCl and HSA, respectively. In contrast, heat-treated spores displayed a strong delay between initial germination and swelling and further outgrowth at pH5.5, resulting in large heterogeneity and low numbers of fastest growers reaching the maximum microcolony stage after 10, 12 and 24h, without and with added NaCl or HSA, respectively. This work shows that Anopore technology provides quantitative information on the impact of combined preservation stresses on outgrowth of single spores, showing that outgrowth of germinated heat-treated spores is significantly affected at pH5.5 with a large fraction of spores arrested in the early outgrowth stage, and with outgrowing cells showing large heterogeneity with only a small fraction committed to relatively fast outgrowth.

  1. New insights in the bacterial spore resistance to extreme terrestrial and extraterrestrial factors

    Science.gov (United States)

    Moeller, Ralf; Horneck, Gerda; Reitz, Guenther

    Based on their unique resistance to various space parameters, Bacillus endospores are one of the model systems used for astrobiological studies. The extremely high resistance of bacterial endospores to environmental stress factors has intrigued researchers since long time and many characteristic spore features, especially those involved in the protection of spore DNA, have already been uncovered. The disclosure of the complete genomic sequence of Bacillus subtilis 168, one of the often used astrobiological model system, and the rapid development of tran-scriptional microarray techniques have opened new opportunities of gaining further insights in the enigma of spore resistance. Spores of B. subtilis were exposed to various extreme ter-restrial and extraterrestrial stressors to reach a better understanding of the DNA protection and repair strategies, which them to cope with the induced DNA damage. Following physical stress factors of environmental importance -either on Earth or in space -were selected for this thesis: (i) mono-and polychromatic UV radiation, (ii) ionizing radiation, (iii) exposure to ultrahigh vacuum; and (iv) high shock pressures simulating meteorite impacts. To reach a most comprehensive understanding of spore resistance to those harsh terrestrial or simulated extraterrestrial conditions, a standardized experimental protocol of the preparation and ana-lyzing methods was established including the determination of the following spore responses: (i) survival, (ii) induced mutations, (iii) DNA damage, (iv) role of different repair pathways by use of a set of repair deficient mutants, and (v) transcriptional responses during spore germi-nation by use of genome-wide transcriptome analyses and confirmation by RT-PCR. From this comprehensive set of data on spore resistance to a variety of environmental stress parameters a model of a "built-in" transcriptional program of bacterial spores in response to DNA damaging treatments to ensure DNA restoration

  2. Effects of Citral on Aspergillus flavus Spores by Quasi-elastic Light Scattering and Multiplex Microanalysis Techniques

    Institute of Scientific and Technical Information of China (English)

    Man LUO; Li-Ke JIANG; Yao-Xiong HUANG; Ming XIAO; Bo LI; Guo-Lin ZOU

    2004-01-01

    Citral refined from Litsea cubeba oil has been found to have a strong influence on fungi,especially Aspergillus flavus. Multiplex microanalysis and quasi-elastic light scattering techniques were applied to study the effects of citral on Aspergillus flavus spores from the levels of membrane, organelle and intracellular macromolecule. It was found that citral injured the wall and the membrane of A. flavus spore,resulting in decrease of its elasticity. After entering the cell, citral not only influenced the genetic expression of mitochondrion reduplication and its morphology, but also changed the aggregation of protein-like macromolecules. As a result, cells, organelles and macromolecules lost their normal structures and functions,eventually leading to the loss of germination ability of A. flavus spores. Since Litsea cubeba oil as food additive and antifungal agent is safe and less poisonous, it is important to elucidate the inhibitory mechanisms of Litsea cubeba oil on the germination ability ofA. flavus spore.

  3. Gas discharge plasmas are effective in inactivating Bacillus and Clostridium spores.

    Science.gov (United States)

    Tseng, Shawn; Abramzon, Nina; Jackson, James O; Lin, Wei-Jen

    2012-03-01

    Bacterial spores are the most resistant form of life and have been a major threat to public health and food safety. Nonthermal atmospheric gas discharge plasma is a novel sterilization method that leaves no chemical residue. In our study, a helium radio-frequency cold plasma jet was used to examine its sporicidal effect on selected strains of Bacillus and Clostridium. The species tested included Bacillus subtilis, Bacillus stearothermophilus, Clostridium sporogenes, Clostridium perfringens, Clostridium difficile, and Clostridium botulinum type A and type E. The plasmas were effective in inactivating selected Bacillus and Clostridia spores with D values (decimal reduction time) ranging from 2 to 8 min. Among all spores tested, C. botulinum type A and C. sporogenes were significantly more resistant to plasma inactivation than other species. Observations by phase contrast microscopy showed that B. subtilis spores were severely damaged by plasmas and the majority of the treated spores were unable to initiate the germination process. There was no detectable fragmentation of the DNA when the spores were treated for up to 20 min. The release of dipicolinic acid was observed almost immediately after the plasma treatment, indicating the spore envelope damage could occur quickly resulting in dipicolinic acid release and the reduction of spore resistance.

  4. Influence of gravity and light on the developmental polarity of Ceratopteris richardii fern spores

    Science.gov (United States)

    Edwards, E. S.; Roux, S. J.

    1998-01-01

    The polarity of germinating single-celled spores of the fern Ceratopteris richardii Brogn. is influenced by gravity during a time period prior to the first cellular division designated a "polarity-determination window". After this window closes, control of polarity is seen in the downward (with respect to gravity) migration of the nucleus along the proximal face of the spore and the subsequent downward growth of the primary rhizoid. When spores are germinated on a clinostat the direction of nuclear migration and subsequent primary rhizoid growth is random. However, in each case the direction of nuclear migration predicts the direction of rhizoid elongation. Although it is the most obvious movement, the downward migration is not the first movement of the nucleus. During the polarity-determination window, the nucleus moves randomly within a region centered behind the trilete marking. While the polarity of many fern spores has been reported to be controlled by light, spores of C. richardii are the first documented to have their polarity influenced by gravity. Directional white light also affects the polarity of these spores, but this influence is slight and is secondary to that of gravity.

  5. Bacterial spore components which enhance the bacteriostatic effectiveness of S-nitrosothiol.

    Science.gov (United States)

    Morris, S L; Hansen, J N

    1981-12-01

    Spore components exuded into the medium during outgrowth of Bacillus cereus T enhanced the bacteriostatic effectiveness of S-nitrosomercaptoethanol, an inhibitor which prevents outgrowth at low concentrations and germination at higher concentrations. The enhancement effect was slight with respect to outgrowth, but dramatic with respect to germination, in that the inhibitory effectiveness of nitrosothiols toward germination inhibition was enhanced by as much as 33-fold when nitrosothiols was in the presence of the exuded spore component. Exudate activity was freely dialyzable and was not measurably affected by a broad-spectrum protease (proteinase K), by autoclaving at 121 degrees C, or by freezing and thawing. Sephadex G-25 chromatography of the exudate indicated that two active species were present, a major component with a molecular weight of less than 1,000 and a minor component with a molecular weight of more than 5,000.

  6. Fungal rhinosinusitis.

    Science.gov (United States)

    Netkovski, J; Shirgoska, B

    2012-01-01

    Fungi are a major part of the ecosystem. In fact, over 250 fungal species have been reported to produce human infections. More than ever, fungal diseases have emerged as major challenges for physicians and clinical microbiologists. The aim of this study was to summarize the diagnostic procedures and endoscopic surgical treatment of patients with fungal rhinosinusitis. Eleven patients, i.e. 10% of all cases with chronic inflammation of paranasal sinuses, were diagnosed with fungal rhinosinusitis. Ten of them were patients with a noninvasive form, fungus ball, while only one patient was classified in the group of chronic invasive fungal rhinosinusitis which was accompanied with diabetes mellitus. All patients underwent nasal endoscopic examination, skin allergy test and had preoperative computed tomography (CT) scans of the sinuses in axial and coronal plane. Functional endoscopic sinus surgery was performed in 10 patients with fungus ball, while a combined approach, endoscopic and external, was done in the immunocompromised patient with the chronic invasive form of fungal rhinosinusitis. Most cases (9/11) had unilateral infection. In 9 cases infection was restricted to a single sinus, and here the maxillary sinus was most commonly affected (8/9) with infections in other patients being restricted to the sphenoid sinus (1/9). Two patients had infections affecting two or more sinuses. In patients with an invasive form of the fungal disease there was involvement of the periorbital and orbital tissues. In patients with fungus ball the mycelia masses were completely removed from the sinus cavities. Long-term outcome was positive in all the operated patients and no recurrence was detected. The most frequent fungal agent that caused rhinosinusitis was Aspergillus. Mucor was identified in the patient with the invasive form. Endoscopic examination of the nasal cavity and CT scanning of paranasal sinuses followed by endoscopic sinus surgery were represented as valuable

  7. Characterizations of atmospheric fungal aerosol in Beijing, China

    Science.gov (United States)

    Liang, Linlin; Engling, Guenter; He, Kebin; Du, Zhenyu

    2013-04-01

    Fungal aerosols constitute the most abundant fraction of biological aerosols in the atmosphere, influencing human health, the biosphere, atmospheric chemistry and climate. However, the total abundance of fungal spores in the atmosphere is still poorly understood and quantified. PM10 and PM2.5 samples were collected by high volume samplers simultaneously at a rural site (MY) and an urban site (THU) in Beijing, China. Various carbohydrates were quantified by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), including the sugar alcohols mannitol and arabitol, proposed as molecular tracers for fungal aerosol. The annual average concentrations of arabitol in PM2.5 and PM10 at the THU site were 7.4±9.4 ng/m3 and 10.3±9.5 ng/m3, and the respective mannitol concentrations were 21.0±20.4 ng/m3 and 31.9±26.9 ng/m3. Compared to PM10, the monthly average concentrations of arabitol and mannitol in PM2.5 did not vary significantly and were present at nearly consistent levels in the different seasons. Moreover, during summer and autumn higher arabitol and mannitol levels than during spring and winter were observed in coarse particles, probably due to different dominant sources of fungal spores in different seasons. In the dry period (i.e., winter and spring) in Beijing, probably only the suspension from exposed surfaces, (e.g., soil resuspension, transported dust, etc.) can be regarded as the main sources for fungal aerosols. On the other hand, in summer and autumn, fungal spores in the atmosphere can be derived from more complex sources, including plants, vegetation decomposition and agricultural activity, such as ploughing; these fungal spore sources may contribute more to coarse PM. Mannitol and arabitol correlated well with each other, both in PM10 (R2 = 0.71) and PM2.5 (R2 = 0.81). Although fungal spore levels at rural sites were consistently higher than those at urban sites in other studies, the findings in our study were

  8. The characterisation of Bacillus spores occurring in the manufacturing of (low acid) canned products.

    Science.gov (United States)

    Oomes, S J C M; van Zuijlen, A C M; Hehenkamp, J O; Witsenboer, H; van der Vossen, J M B M; Brul, S

    2007-11-30

    Spore-forming bacteria can be a problem in the food industry, especially in the canning industry. Spores present in ingredients or present in the processing environment severely challenge the preservation process since their thermal resistance may be very high. We therefore asked the question which bacterial spore formers are found in a typical soup manufacturing plant, where they originate from and what the thermal resistance of their spores is. To answer these questions molecular techniques for bacterial species and strain identification were used as well as a protocol for the assessment of spore heat stress resistance based on the Kooiman method. The data indicate the existence and physiological cause of the high thermal resistance of spores of many of the occurring species. In particular it shows that ingredients used in soup manufacturing are a rich source of high thermal resistant spores and that sporulation in the presence of ingredients rich in divalent metal ions exerts a strong influence on spore heat resistance. It was also indicated that Bacillus spores may well be able to germinate and resporulate during manufacturing i.e. through growth and sporulation in line. Both these spores and those originating from the ingredients were able to survive certain thermal processing settings. Species identity was confirmed using fatty acid analysis, 16SrRNA gene sequencing and DNA-DNA hybridisation. Finally, molecular typing experiments using Ribotyping and AFLP analysis show that strains within the various Bacillus species can be clustered according to the thermal resistance properties of their spores. AFLP performed slightly better than Ribotyping. The data proofed to be useful for the generation of strain specific probes. Protocols to validate these probes in routine identification and innovation aimed at tailor made heat processing in soup manufacturing have been formulated.

  9. 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

    subtilis mutants to probe mechanisms of spore germination and inactivation. We employ techniques of high-resolution atomic force microscopy and phase contrast microscopy to examine the effects of γ-irradiation on bacterial spores of Bacillus anthracis, Bacillus thuringiensis, and Bacillus atrophaeus spp. and of ClO2 on B. subtilis spores, and present in detail assays using spore bio-indicators to ensure sterility when decontaminating with ClO2.

  10. 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

    subtilis mutants to probe mechanisms of spore germination and inactivation. We employ techniques of high-resolution atomic force microscopy and phase contrast microscopy to examine the effects of γ-irradiation on bacterial spores of Bacillus anthracis, Bacillus thuringiensis, and Bacillus atrophaeus spp. and of ClO2 on B. subtilis spores, and present in detail assays using spore bio-indicators to ensure sterility when decontaminating with ClO2. PMID:26322021

  11. Prevalence and airborne spore levels of Stachybotrys spp. in 200 houses with water incursions in Houston, Texas.

    Science.gov (United States)

    Kuhn, Ryan C; Trimble, Mingyi W; Hofer, Vasanthi; Lee, Michael; Nassof, Russell S

    2005-01-01

    Two hundred homes with a history of water incursion were sampled for fungi to determine the prevalence and airborne spore levels of Stachybotrys spp. Sampling methods included room air, surface, and wall cavity air sampling. Stachybotrys spp. were detected with at least one of the methods in 58.5% of the houses tested, but only 9.6% of the room air samples contained Stachybotrys spores. Aerosolization of Stachybotrys spores was correlated with both wall cavity and surface contamination. However, after adjustment for the surface effect, Stachybotrys spores detected in wall cavities were not a significant factor contributing to spores detected in room air samples. We conclude that Stachybotrys spp. are commonly found on water-damaged building materials. In addition, the observations made in this study suggest that the impact on the living space air is low if the fungal spores are contained within a wall cavity.

  12. Abiotic environmental conditions for germination and development of gametophytes of Cyathea phalerata Mart. (Cyatheaceae

    Directory of Open Access Journals (Sweden)

    Catiuscia Marcon

    Full Text Available ABSTRACT In order to successfully establish themselves in their natural environment, ferns need habitats with abiotic conditions that are suitable for spore germination and gametophyte development. The objective of this study was to assess the influence of abiotic factors on the initial development of Cyathea phalerata cultivated in vitro. Spore germination and gametophyte development were assessed under varying conditions of surface sterilization, pH, temperature and photoperiod. Exogenous contamination was eliminated by sterilizing spores with 2.5 % NaClO for 15 min and sowing them into a culture medium supplemented with nystatin. Spores germinated at all pHs tested. Gametophytic development was faster in acidic pHs. Cultures at 25 °C exhibited the highest percentages of germination and laminar gametophytes. The species produced its highest percentages of gametophytes in cultures with photoperiods between 6 and 18 h. The optimal abiotic conditions found here for in vitro development of C. phalerata are similar to those found in its natural habitat. The southern limit of this species to north of the 30th parallel in Rio Grande do Sul, Brazil, may be because further south spores do not encounter the ideal combined conditions of temperature, pH and photoperiod determined in the laboratory.

  13. Evaluation of the microbial quality of Tajik sambusa and control of Clostridium perfringens germination and outgrowth by buffered sodium citrate and potassium lactate.

    Science.gov (United States)

    Yarbaeva, Shakhlo N; Velugoti, Padmanabha R; Thippareddi, Harshavardhan; Albrecht, Julie A

    2008-01-01

    Clostridium perfringens spore destruction, aerobic plate counts (APCs), and counts of Enterobacteriaceae, coliforms, and Escherichia coli during baking of sambusa (a traditional Tajik food) were evaluated. Control of germination and outgrowth of C. perfringens spores in sambusa during cooling at room or refrigerated temperatures was evaluated using organic acid salts (buffered sodium citrate [Ional] and 1 and 2% potassium lactate, wt/wt). Sambusa were prepared with 40 g of either inoculated or noninoculated meat and baked for 45 min at 180 degrees C. For evaluation of destruction of C. perfringens spores during heating and germination and outgrowth of spores during cooling, ground beef was inoculated and mixed with a three-strain cocktail of C. perfringens spores. Aerobic bacteria, Enterobacteriaceae, coliforms, and E. coli were enumerated in noninoculated sambusa before and after baking and after cooling at room or refrigeration temperatures. After baking, APCs and Enterobacteriaceae and coliform counts were reduced by 4.32, 2.55, and 1.96 log CFU/g, respectively. E. coli counts were below detectable levels in ground beef and sambusa samples. Enterobacteriaceae, coliform, and E. coli counts were below detectable levels (sodium citrate controlled C. perfringens spore germination and outgrowth (0.25 log CFU/g), whereas incorporation of up to 2% (wt/wt) potassium lactate did not prevent C. perfringens spore germination and outgrowth. Incorporation of organic acid salts at appropriate concentrations can prevent germination and outgrowth of C. perfringens in improperly cooled sambusa.

  14. Review of fungal outbreaks and infection prevention in healthcare settings during construction and renovation.

    Science.gov (United States)

    Kanamori, Hajime; Rutala, William A; Sickbert-Bennett, Emily E; Weber, David J

    2015-08-01

    Hospital construction and renovation activities are an ever-constant phenomenon in healthcare facilities, causing dust contamination and possible dispersal of fungal spores. We reviewed fungal outbreaks that occurred during construction and renovation over the last 4 decades as well as current infection prevention strategies and control measures. Fungal outbreaks still occur in healthcare settings, especially among patients with hematological malignancies and those who are immunocompromised. The causative pathogens of these outbreaks were usually Aspergillus species, but Zygomycetes and other fungi were occasionally reported. Aspergillus most commonly caused pulmonary infection. The overall mortality of construction/renovation-associated fungal infection was approximately 50%. The minimal concentration of fungal spores by air sampling for acquisition of fungal infections remains to be determined. Performing infection control risk assessments and implementing the recommended control measures is essential to prevent healthcare-associated fungal outbreaks during construction and renovation.

  15. Fumigant antifungal activity of Corymbia citriodora and Cymbopogon nardus essential oils and citronellal against three fungal species.

    Science.gov (United States)

    Aguiar, Raimundo Wagner de S; Ootani, Marcio A; Ascencio, Sérgio Donizeti; Ferreira, Talita P S; Dos Santos, Manoel M; dos Santos, Gil R

    2014-01-01

    Corymbia citriodora and Cymbopogon nardus essential oils samples were analyzed by GC and GC-MS and their qualitative and quantitative compositions established. The main component of essential oils of C. citriodora and C. nardus was citronellal, at 61.78% and 36.6%, respectively. The essential oils and citronellal were tested for their fumigant antifungal activity against Pyricularia (Magnaporthe) grisea, Aspergillus spp., and Colletotrichum musae. The minimum inhibitory concentration (MIC) ranged from 100 to 200 ppm for the essential oils and 25 to 50 mg · mL(-1) for citronellal. The contact assay using the essential oils and citronellal showed growth inhibition of the three fungal species. However, a concentration of 1.47 mg · mL(-1) only reduced the inhibition of Aspergillus growth to 90% at 14 days of exposure. For the fumigant assay, 0.05, 0.11, and 0.23 mg · mL(-1) of essential oils and citronellal drastically affected growth of P. grisea, Aspergillus spp., and C. musae. Harmful effects on the sporulation and germination of the three fungi were seen, and there was complete inhibition at 0.15 mg · mL(-1) with both oils and citronellal. This showed that the crude component of essential oils of C. citriodora and C. nardus markedly suppressed spore production, germination, and growth inhibition of P. grisea, Aspergillus spp., and Colletotrichum musae.

  16. Fumigant Antifungal Activity of Corymbia citriodora and Cymbopogon nardus Essential Oils and Citronellal against Three Fungal Species

    Directory of Open Access Journals (Sweden)

    Raimundo Wagner de S. Aguiar

    2014-01-01

    Full Text Available Corymbia citriodora and Cymbopogon nardus essential oils samples were analyzed by GC and GC-MS and their qualitative and quantitative compositions established. The main component of essential oils of C. citriodora and C. nardus was citronellal, at 61.78% and 36.6%, respectively. The essential oils and citronellal were tested for their fumigant antifungal activity against Pyricularia (Magnaporthe grisea, Aspergillus spp., and Colletotrichum musae. The minimum inhibitory concentration (MIC ranged from 100 to 200 ppm for the essential oils and 25 to 50 mg·mL−1 for citronellal. The contact assay using the essential oils and citronellal showed growth inhibition of the three fungal species. However, a concentration of 1.47 mg·mL−1 only reduced the inhibition of Aspergillus growth to 90% at 14 days of exposure. For the fumigant assay, 0.05, 0.11, and 0.23 mg·mL−1 of essential oils and citronellal drastically affected growth of P. grisea, Aspergillus spp., and C. musae. Harmful effects on the sporulation and germination of the three fungi were seen, and there was complete inhibition at 0.15 mg·mL−1 with both oils and citronellal. This showed that the crude component of essential oils of C. citriodora and C. nardus markedly suppressed spore production, germination, and growth inhibition of P. grisea, Aspergillus spp., and Colletotrichum musae.

  17. Bacterial spore survival after exposure to HZE particle bombardment -implication for the lithopanspermia hypothesis.

    Science.gov (United States)

    Moeller, Ralf; Berger, Thomas; Matthiä, Daniel; Okayasu, Ryuichi; Kitamura, H.; Reitz, Guenther

    transcriptional response during spore germination" (Moeller et al., 2008 [3]). To simulate the interplanetary journey of a meteorite, stacks of spore-samples on gabbro slides in different depths were exposed. Spore survival and the rate of the induced mutations (i.e., sporulation-deficiency (Spo-)) depended on the LET of the applied species of ions as well as on the location (and depth) of the irradiated spores in the artificial meteorite. The exposure to high LET iron ions led to a low level of spore survival and increased frequency of mutation to Spo-compared to low-energy charged particles compared to the low LET helium ions. In order to obtain insights on the role of DNA repair by nonhomologous end joining (NHEJ), homologous recombination (HR) and apurinic/apyrimidinic (AP) endonucleases in B. subtilis spore resistance to high-energy charged particles has been studied in parallel. Spores deficient in NHEJ and AP endonucleases were significantly more sensitive to HZE particle bombardment than were the HR-mutant and wild-type spores, indicating that NHEJ and AP endonucleases provide DNA break repair pathways during spore germination. ((References: [1] Arrhenius, S. 1903. Die Verbreitung des Lebens im Weltenraum. Umschau 7:481-485.; [2] Nicholson, W. L. 2009. Ancient micronauts: interplanetary transport of microbes by cosmic impacts. Trends Mi-crobiol. 17:243-250.; [3] Moeller, R., P. Setlow, G. Horneck, T. Berger, G. Reitz, P. Rettberg, A. J. Doherty, R. Okayasu, and W. L. Nicholson. 2008. Roles of the major, small, acid-soluble spore proteins and spore-specific and universal DNA repair mechanisms in resistance of Bacillus subtilis spores to ionizing radiation from X-rays and high-energy charged-particle bombardment. J. Bacteriol. 190:1134-1140.))

  18. Fungal nail infection

    Science.gov (United States)

    Nails - fungal infection; Onychomycosis; Infection - fungal - nails; Tinea unguium ... hair, nails, and outer skin layers. Common fungal infections include: Athlete's foot Jock itch Ringworm on the ...

  19. Effect of surfactants and temperature on germination and vegetative growth of Beauveria bassiana

    Directory of Open Access Journals (Sweden)

    Lizzy A. Mwamburi

    2015-03-01

    Full Text Available Three non-ionic surfactants: Tween20, Tween80 and Breakthru® were screened for their effects on spore germination and mycelial growth rates and for their influence on three isolates of Beauveria bassianaspore germination at various temperatures. Tween20 and Tween80 were compatible with all the B. bassiana isolates in the germination studies, but inhibited germination at higher surfactant concentrations, irrespective of the conidial concentrations. Breakthru® had an inhibitory effect on germination even at the lowest concentration of 0.1% on all the B. bassiana isolates. The effects of the surfactants on spore germination did not correspond with their effects on colony growth. Conidial viability within the same formulation declined significantly with increases in temperature, irrespective of the surfactant. The optimal temperature for conidial germination of B. bassiana isolates was approximately 25 °C with an upper limit at 30 °C. Isolate 7320 was identified as the least affected by the different surfactants. This isolate was able to germinate rapidly in a broad temperature range of 25–30 °C after 24 h, this characteristic being an essential factor in controlling house fly populations in poultry houses.

  20. Germination and outgrowth of spores of Bacillus cereus group members: Diversity and role of germinant receptors

    NARCIS (Netherlands)

    Abee, T.; Nierop Groot, M.N.; Tempelaars, M.H.; Zwietering, M.H.; Moezelaar, R.; Voort, van der M.

    2011-01-01

    Bacillus cereus is a Gram-positive, facultative anaerobic, endospore-forming toxicogenic human pathogen. Endospores are highly specialized, metabolically dormant cell types that are resistant to extreme environmental conditions, including heat, dehydration and other physical stresses. B. cereus can

  1. Monitoring and assessment of airborne Cladosporium Link and Alternaria Nées spores in Sivrihisar (Eskisehir), Turkey.

    Science.gov (United States)

    Erkara, Ismuhan Potoglu; Ilhan, Semra; Oner, Setenay

    2009-01-01

    The spores of Cladosporium spp. and Alternaria spp., commonly described as the most allergenic spores, were collected by means of Durham gravimetric sampler from the Sivrihisar (Eskisehir) atmosphere throughout 2005 to 2006. The weekly variations in spores/cm(2) of Cladosporium and Alternaria were recorded. During this period, a total of 6,198 spores belonging to Cladosporium spp. and Alternaria spp. were recorded. Of these spores, 2,969 were identified in 2005 and 3,229 in 2006. While 69.55% of the total spores were those of Cladosporium spp., 30.45% were Alternaria spp. Relationships between airborne fungal spore presence and weather conditions were examined statistically. A Shapiro-Wilk test revealed that the airborne spores of Cladosporium spp. and Alternaria spp. had a normal distribution. Following this, Chi-square test, t test and Pearson correlation analysis were performed. The effects of temperature and relative humidity on the spore numbers of Cladosporium spp. and Alternaria spp. were significant according to the month in which they were collected (p < 0.01). The spore concentrations of each species reached to their highest levels in June 2006.

  2. Investigation of bacterial spore structure by high resolution solid-state nuclear magnetic resonance spectroscopy and transmission electron microscopy.

    Science.gov (United States)

    Leuschner, R G; Lillford, P J

    2001-01-22

    High resolution solid-state nuclear magnetic resonance spectroscopy (NMR) in combination with transmission electron microscopy (TEM) of spores of Bacillus cereus, an outer coatless mutant B. subtilis 322, an inner coatless mutant B. subtilis 325 and of germinated spores of B. subtilis CMCC 604 were carried out. Structural differences in the coats, mainly protein of spores were reflected by NMR spectra which indicated also differences in molecular mobility of carbohydrates which was partially attributed to the cortex. Dipicolinic acid (DPA) of spores of B. cereus displayed a high degree of solid state order and may be crystalline. Heat activation was studied on spores of B. subtilis 357 lux + and revealed a structural change when analysed by TEM but this was not associated with increases in molecular mobility since no effects were measured by NMR.

  3. Direct investigation of viscosity of an atypical inner membrane of Bacillus spores: a molecular rotor/FLIM study.

    Science.gov (United States)

    Loison, Pauline; Hosny, Neveen A; Gervais, Patrick; Champion, Dominique; Kuimova, Marina K; Perrier-Cornet, Jean-Marie

    2013-11-01

    We utilize the fluorescent molecular rotor Bodipy-C12 to investigate the viscoelastic properties of hydrophobic layers of bacterial spores Bacillus subtilis. The molecular rotor shows a marked increase in fluorescence lifetime, from 0.3 to 4ns, upon viscosity increase from 1 to 1500cP and can be incorporated into the hydrophobic layers within the spores from dormant state through to germination. We use fluorescence lifetime imaging microscopy to visualize the viscosity inside different compartments of the bacterial spore in order to investigate the inner membrane and relate its compaction to the extreme resistance observed during exposure of spores to toxic chemicals. We demonstrate that the bacterial spores possess an inner membrane that is characterized by a very high viscosity, exceeding 1000cP, where the lipid bilayer is likely in a gel state. We also show that this membrane evolves during germination to reach a viscosity value close to that of a vegetative cell membrane, ca. 600cP. The present study demonstrates quantitative imaging of the microscopic viscosity in hydrophobic layers of bacterial spores Bacillus subtilis and shows the potential for further investigation of spore membranes under environmental stress.

  4. Fungal keratitis

    Directory of Open Access Journals (Sweden)

    Sonal S Tuli

    2011-02-01

    Full Text Available Sonal S TuliUniversity of Florida, Gainesville, FL, USA  Clinical question: What is the most appropriate management of fungal keratitis?Results: Traditionally, topical Natamycin is the most commonly used medication for filamentous fungi while Amphotericin B is most commonly used for yeast. Voriconazole is rapidly becoming the drug of choice for all fungal keratitis because of its wide spectrum of coverage and increased penetration into the cornea.Implementation: Repeated debridement of the ulcer is recommended for the penetration of topical medications. While small, peripheral ulcers may be treated in the community, larger or central ulcers, especially if associated with signs suggestive of anterior chamber penetration should be referred to a tertiary center. Prolonged therapy for approximately four weeks is usually necessary.Keywords: fungal keratitis, keratomycosis, antifungal medications, debridement

  5. Rupturing of Biological Spores As a Source of Secondary Particles in Amazonia

    Energy Technology Data Exchange (ETDEWEB)

    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 play an important role in 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 nanometer to submicron 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 nanoparticles and may provide insight into new particle formation in Amazonia.

  6. Hydrazine vapor inactivates Bacillus spores

    Science.gov (United States)

    Schubert, Wayne W.; Engler, Diane L.; Beaudet, Robert A.

    2016-05-01

    NASA policy restricts the total number of bacterial spores that can remain on a spacecraft traveling to any planetary body which might harbor life or have evidence of past life. Hydrazine, N2H4, is commonly used as a propellant on spacecraft. Hydrazine as a liquid is known to inactivate bacterial spores. We have now verified that hydrazine vapor also inactivates bacterial spores. After Bacillus atrophaeus ATCC 9372 spores deposited on stainless steel coupons were exposed to saturated hydrazine vapor in closed containers, the spores were recovered from the coupons, serially diluted, pour plated and the surviving bacterial colonies were counted. The exposure times required to reduce the spore population by a factor of ten, known as the D-value, were 4.70 ± 0.50 h at 25 °C and 2.85 ± 0.13 h at 35 °C. These inactivation rates are short enough to ensure that the bioburden of the surfaces and volumes would be negligible after prolonged exposure to hydrazine vapor. Thus, all the propellant tubing and internal tank surfaces exposed to hydrazine vapor do not contribute to the total spore count.

  7. Seed germination and vigor.

    Science.gov (United States)

    Rajjou, Loïc; Duval, Manuel; Gallardo, Karine; Catusse, Julie; Bally, Julia; Job, Claudette; Job, Dominique

    2012-01-01

    Germination vigor is driven by the ability of the plant embryo, embedded within the seed, to resume its metabolic activity in a coordinated and sequential manner. Studies using "-omics" approaches support the finding that a main contributor of seed germination success is the quality of the messenger RNAs stored during embryo maturation on the mother plant. In addition, proteostasis and DNA integrity play a major role in the germination phenotype. Because of its pivotal role in cell metabolism and its close relationships with hormone signaling pathways regulating seed germination, the sulfur amino acid metabolism pathway represents a key biochemical determinant of the commitment of the seed to initiate its development toward germination. This review highlights that germination vigor depends on multiple biochemical and molecular variables. Their characterization is expected to deliver new markers of seed quality that can be used in breeding programs and/or in biotechnological approaches to improve crop yields.

  8. Development and application of a microplate method to evaluate the efficacy of essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. & M.A. Curtis Arx, three postharvest fungal pathogens of fruits

    Directory of Open Access Journals (Sweden)

    Bajji, M.

    2012-01-01

    Full Text Available A microbioassay was developed for evaluating the in vitro antifungal activity of 30 preselected essential oils. A template based on 10 serial dilutions with eight replicates per dilution arranged on two 96-well ELISA plates was used as a reproducible and standardized design to identify the in vitro effectiveness of these essential oils against Penicillium italicum Wehmer, Penicillium digitatum Sacc. and Colletotrichum musea (Berk. & M.A. Curtis Arx, three postharvest fungal pathogens, on fruits. Growth of mycelium was monitored by measuring optical density (492 nm. Cinnamomum zeylanicum, Cinnamomum verum and Eugenia caryophyllus were found to be still active against all the three pathogens even at 100 ppm. Compared to other methods, this microbioassay proved to be a rapid, reproducible, and efficient method for testing the efficacy of essential oils that inhibit spore germination in P. italicum, P. digitatum and C. musea. The assay requires relatively small amounts of essential oils.

  9. Mycoflora in Exhumed Seeds of Opuntia tomentosa and Its Possible Role in Seed Germination

    Directory of Open Access Journals (Sweden)

    María Esther Sánchez-Coronado

    2011-01-01

    Full Text Available The funicular cover of the Opuntia tomentosa seed limits imbibition; germination occurs only when the funicle is weakened or the funicular valve is removed. We investigated the role of fungi in funicular weakening and seed germination. Seeds that had been either buried in one of two sites or stored in the laboratory were germinated with and without a valve. Disinfected or nondisinfected seeds and their naked embryos were cultivated on agar or PDA. None of the 11 identified fungal genera grew on the disinfected control seeds or the embryos. The mycoflora present on disinfected and nondisinfected exhumed seeds suggest that the fungal colonization occurred in the soil and differed between the burial sites. Exhumed seeds with and without a valve germinated in high percentages, whereas only the control seeds without a valve germinated. Scanning electron micrographs showed that the hyphae penetrated, cracked, and eroded the funicular envelope of exhumed seeds.

  10. Fungal prions.

    Science.gov (United States)

    Staniforth, Gemma L; Tuite, Mick F

    2012-01-01

    For both mammalian and fungal prion proteins, conformational templating drives the phenomenon of protein-only infectivity. The conformational conversion of a protein to its transmissible prion state is associated with changes to host cellular physiology. In mammals, this change is synonymous with disease, whereas in fungi no notable detrimental effect on the host is typically observed. Instead, fungal prions can serve as epigenetic regulators of inheritance in the form of partial loss-of-function phenotypes. In the presence of environmental challenges, the prion state [PRION(+)], with its resource for phenotypic plasticity, can be associated with a growth advantage. The growing number of yeast proteins that can switch to a heritable [PRION(+)] form represents diverse and metabolically penetrating cellular functions, suggesting that the [PRION(+)] state in yeast is a functional one, albeit rarely found in nature. In this chapter, we introduce the biochemical and genetic properties of fungal prions, many of which are shared by the mammalian prion protein PrP, and then outline the major contributions that studies on fungal prions have made to prion biology.

  11. Fungal Entomopathogens

    Science.gov (United States)

    Fungal entomopathogens are important biological control agents worldwide and have been the subject of intense research for more than100 years. They exhibit both sexual and asexual reproduction and produce different types of infective propagules. Their mode of action against insects involves attachme...

  12. Development of natto with germination-defective mutants of Bacillus subtilis (natto).

    Science.gov (United States)

    Mitsui, Nobuo; Murasawa, Hisashi; Sekiguchi, Junichi

    2009-03-01

    The effects of cortex-lysis related genes with the pdaA, sleB, and cwlD mutations of Bacillus subtilis (natto) NAFM5 on sporulation and germination were investigated. Single or double mutations did not prevent normal sporulation, but did affect germination. Germination was severely inhibited by the double mutation of sleB and cwlD. The quality of natto made with the sleB cwlD double mutant was tested, and the amounts of glutamic acid and ammonia were very similar to those in the wild type. The possibility of industrial development of natto containing a reduced number of viable spores is presented.

  13. Inhibition of Bacillus licheniformis spore growth in milk by nisin, monolaurin, and pH combinations.

    Science.gov (United States)

    Mansour, M; Amri, D; Bouttefroy, A; Linder, M; Milliere, J B

    1999-02-01

    The effects of nisin and monolaurin, alone and in combination, were investigated on Bacillus licheniformis spores in milk at 37 degrees C. In the absence of inhibitors, germinated spores developed into growing vegetative cells and started sporulation at the end of the exponential phase. In the presence of nisin (25 IU ml-1), spore outgrowth was inhibited (4 log10 reduction at 10 h). Regrowth appeared between 10 and 24 h and reached a high population level (1.25 x 10(8) cfu ml-1) after 7 d. Monolaurin (250 micrograms ml-1) had a bacteriostatic effect during the first 10 h but thereafter, regrowth occurred slowly with a population level after 7 d (4 x 10(5) cfu ml-1) lower than that of nisin. Different combined effects of nisin (between 0 and 42 IU ml-1), monolaurin (ranging from 0 to 300 micrograms ml-1), pH values (between 5.0 and 7.0) and spore loads (10(3), 10(4), 10(5) spores ml-1) were investigated using a Doehlert matrix in order to study the main effects of these factors and the different interactions. Results were analysed using the Response Surface Methodology (RSM) and indicated that nisin and monolaurin had no action on spores before germination; only pH values had a significant effect (P monolaurin (100 micrograms ml-1) in combination acted synergistically on outgrown spores and vegetative cells, showing total inhibition at pH 6.0, without regrowth, within 7 d at 37 degrees C.

  14. Bioluminescence: a fungal nightlight with an internal timer.

    Science.gov (United States)

    Bechara, Etelvino J H

    2015-03-30

    A recent study shows that green light emission by Neonothopanus gardneri mushrooms, endemic to coconut forests of Northern Brazil, is controlled by a circadian clock. Furthermore, insects are attracted by the light, raising the possibility that bioluminescence functions in spore dispersal and fungal dissemination. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. NASA Facts: SporeSat

    Science.gov (United States)

    Martinez, Andres; Cappuccio, Gelsomina; Tomko, David

    2013-01-01

    SporeSat is an autonomous, free-flying three-unit (3U) spacecraft that will be used to conduct scientific experiments to gain a deeper knowledge of the mechanisms of plant cell gravity sensing. SporeSat is being developed through a partnership between NASAs Ames Research Center and the Department of Agricultural and Biological Engineering at Purdue University. Amani Salim and Jenna L. Rickus are the Purdue University Principal Investigators. The SporeSat mission will be flown using a 3U nanosatellite weighing approximately 12 pounds and measuring 14 inches long by 4 inches wide by 4 inches tall. SporeSat will utilize flight-proven spacecraft technologies demonstrated on prior Ames nanosatellite missions such as PharmaSat and OrganismOrganic Exposure to Orbital Stresses (OOREOS) as well as upgrades that increase the hardware integration capabilities with SporeSat science instrumentation. In addition, the SporeSat science payload will serve as a technology platform to evaluate new microsensor technologies for enabling future fundamental biology missions.

  16. 大豆茎溃疡病菌子囊壳诱导及孢子萌发方法探索%Method of the perithecium producing and ascospore germination of Diaporthe phaseolorum

    Institute of Scientific and Technical Information of China (English)

    李会平; 师情; 王凯

    2012-01-01

    Diaporthe phaseolomm is a potential dangerous fungus to soybean. Determination method for obtaining a big amount of ascospores and a reliable spore germination rate is the base of quarantine treatment and control. On the basis of acquiring quantities of perithecium of D. phaseolomm, a new method of ascospore germination with perithecium as the observation unit was explored. In the test, the traditional suspended drops method and water agar surface germination method were used as reference. The results showed that the germination rate of perithecium germination method was lower than that of traditional method in the earlier stage (12 h, 24 h, 36 h), then became in accordance with the traditional method gradually. So, for pathogenetic fungi which can easily produce quantities of perithecium on the host organization and difficultly obtain ascospore , perithecium germination method has reference value on spore germination rate determination.

  17. EFFECTS OF LIGHT WAVELENGTHS AND COHERENCE ON BASIDIOSPORES GERMINATION

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    Natalia Poyedinok

    2015-02-01

    Full Text Available The effects of light wavelengths and coherence on basidiospore germination of Agaricus bisporus, Flammulina velutipes, Ganoderma applanatum, Ganoderma lucidum, Hericium erinaceus, Lentinus edodes and Pleurotus ostreatus have been studied. Short-term low-intensity irradiation by coherent (laser light wavelength 488.0 nm and 632.8 nm at doses 45 and 230 mJ/cm2 has significantly increased the number of germinated basidiospores. It has established that there are differences in the photosensitivity not only between species but also between strains. Spores irradiation by 514.5 nm light has been either neutral or inhibitory. A comparative analysis of basidiospores sensitivity to laser and LED light has also been conducted. To stimulate germination of basidiospores and growth of monokaryons the most suitable solution was to use red coherent and incoherent light of 632.8 nm and 660,0 nm for A. bisporus, G. applanatum and P. ostreatus, red and blue coherent light of 632.8 nm and 488,0 nm for F. velutipes, and both red and blue laser and LED light G. lucidum and H. erinaceus and for L. edodes. No essential difference of a continuous wave mode and intermittent mode light effect at the same doses and wavelength on spore germination were revealed. Light influence has reduced germination time and formation of aerial mycelium on agar medium as compared to the original value and increased the growth rate of monosporous isolates. Characterization of basidiospores photosensitivity and development of environmentally friendly stimulating methods of their germination is important for creating highly effective technologies of mushrooms selection and cultivation.

  18. Evaluation of fungal air contamination in selected wards of two tertiary hospitals in Tehran, Iran

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    Zahra Kamali Sarwestani

    2017-07-01

    Conclusion: According to the results of this study, the frequency and diversity of fungal spores in hospital wards were different. In addition, since the fungal contamination in the hospital environment are affected by various environmental factors and the efficiency of ventilation systems, some of these wards require better ventilation system as well as regular monitoring to remove these fungal bioaerosols in order to maintain the health of patients and health care workers.

  19. EPICHLOE SPECIES: fungal symbionts of grasses.

    Science.gov (United States)

    Schardl, C L

    1996-01-01

    Epichloë species and their asexual descendants (Acremonium endophytes) are fungal symbionts of C3 grasses that span the symbiotic continuum from antagonism to mutualism depending on the relative importance, respectively, of horizontal transmission of sexual spores versus vertical clonal transmission in healthy grass seeds. At least seven sexual Epichloë species are identifiable by mating tests, and many asexual genotypes are interspecific hybrids. Benefits conferred by the symbionts on host plants include protection from biotic factors and abiotic stresses such as drought. Four classes of beneficial alkaloids are associated with the symbionts: ergot alkaloids, indolediterpenes (lolitrems), peramine, and saturated aminopyrrolizidines (lolines). These alkaloids protect host plants from insect and vertebrate herbivores, including livestock. Genetic engineering of the fungal symbionts as more suitable biological protectants for forage grasses requires identification of fungal genes for alkaloid biosynthesis, and DNA-mediated transformation of the fungi.

  20. Release and characteristics of fungal fragments in various conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mensah-Attipoe, Jacob [Department of Environmental Science, University of Eastern Finland, Yliopistonranta 1D, P. O. Box 1627, FI-70211 Kuopio (Finland); Saari, Sampo [Department of Physics, Tampere University of Technology, Korkeakoulunkatu 3, 33720 Tampere (Finland); Veijalainen, Anna-Maria; Pasanen, Pertti [Department of Environmental Science, University of Eastern Finland, Yliopistonranta 1D, P. O. Box 1627, FI-70211 Kuopio (Finland); Keskinen, Jorma [Department of Physics, Tampere University of Technology, Korkeakoulunkatu 3, 33720 Tampere (Finland); Leskinen, Jari T.T. [SIB Labs, University of Eastern Finland, Yliopistonranta 1E, P. O. Box 1627, FI-70211, Kuopio (Finland); Reponen, Tiina, E-mail: reponeta@ucmail.uc.edu [Department of Environmental Science, University of Eastern Finland, Yliopistonranta 1D, P. O. Box 1627, FI-70211 Kuopio (Finland); Department of Environmental Health, University of Cincinnati, P.O. Box 670056, Cincinnati, OH 45267-0056 (United States)

    2016-03-15

    Intact spores and submicrometer size fragments are released from moldy building materials during growth and sporulation. It is unclear whether all fragments originate from fungal growth or if small pieces of building materials are also aerosolized as a result of microbial decomposition. In addition, particles may be formed through nucleation from secondary metabolites of fungi, such as microbial volatile organic compounds (MVOCs). In this study, we used the elemental composition of particles to characterize the origin of submicrometer fragments released from materials contaminated by fungi. Particles from three fungal species (Aspergillus versicolor, Cladosporium cladosporioides and Penicillium brevicompactum), grown on agar, wood and gypsum board were aerosolized using the Fungal Spore Source Strength Tester (FSSST) at three air velocities (5, 16 and 27 m/s). Released spores (optical size, d{sub p} ≥ 0.8 μm) and fragments (d{sub p} ≤ 0.8 μm) were counted using direct-reading optical aerosol instruments. Particles were also collected on filters, and their morphology and elemental composition analyzed using scanning electron microscopes (SEMs) coupled with an Energy-Dispersive X-ray spectroscopy (EDX). Among the studied factors, air velocity resulted in the most consistent trends in the release of fungal particles. Total concentrations of both fragments and spores increased with an increase in air velocity for all species whereas fragment–spore (F/S) ratios decreased. EDX analysis showed common elements, such as C, O, Mg and Ca, for blank material samples and fungal growth. However, N and P were exclusive to the fungal growth, and therefore were used to differentiate biological fragments from non-biological ones. Our results indicated that majority of fragments contained N and P. Because we observed increased release of fragments with increased air velocities, nucleation of MVOCs was likely not a relevant process in the formation of fungal fragments. Based

  1. Diversity of the Germination Apparatus in Clostridium botulinum Groups I, II, III, and IV

    Science.gov (United States)

    Brunt, Jason; van Vliet, Arnoud H. M.; van den Bos, Fédor; Carter, Andrew T.; Peck, Michael W.

    2016-01-01

    Clostridium botulinum is a highly dangerous pathogen that forms very resistant endospores that are ubiquitous in the environment, and which, under favorable conditions germinate to produce vegetative cells that multiply and form the exceptionally potent botulinum neurotoxin. To improve the control of botulinum neurotoxin-forming clostridia, it is important to understand the mechanisms involved in spore germination. Here we present models for spore germination in C. botulinum based on comparative genomics analyses, with C. botulinum Groups I and III sharing similar pathways, which differ from those proposed for C. botulinum Groups II and IV. All spores germinate in response to amino acids interacting with a germinant receptor, with four types of germinant receptor identified [encoded by various combinations of gerA, gerB, and gerC genes (gerX)]. There are three gene clusters with an ABC-like configuration; ABC [gerX1], ABABCB [gerX2] and ACxBBB [gerX4], and a single CA-B [gerX3] gene cluster. Subtypes have been identified for most germinant receptor types, and the individual GerX subunits of each cluster show similar grouping in phylogenetic trees. C. botulinum Group I contained the largest variety of gerX subtypes, with three gerX1, three gerX2, and one gerX3 subtypes, while C. botulinum Group III contained two gerX1 types and one gerX4. C. botulinum Groups II and IV contained a single germinant receptor, gerX3 and gerX1, respectively. It is likely that all four C. botulinum Groups include a SpoVA channel involved in dipicolinic acid release. The cortex-lytic enzymes present in C. botulinum Groups I and III appear to be CwlJ and SleB, while in C. botulinum Groups II and IV, SleC appears to be important. PMID:27840626

  2. Diversity of the Germination Apparatus in Clostridium botulinum Groups I, II, III and IV

    Directory of Open Access Journals (Sweden)

    Jason Brunt

    2016-10-01

    Full Text Available Clostridium botulinum is a highly dangerous pathogen that forms very resistant endospores that are ubiquitous in the environment, and which, under favourable conditions germinate to produce vegetative cells that multiply and form the exceptionally potent botulinum neurotoxin. To improve the control of botulinum neurotoxin-forming clostridia, it is important to understand the mechanisms involved in spore germination. Here we present models for spore germination in C. botulinum based on comparative genomics analyses, with C. botulinum Groups I and III sharing similar pathways, which differ from those proposed for C. botulinum Groups II and IV. All spores germinate in response to amino acids interacting with a germinant receptor, with four types of germinant receptor identified (encoded by various combinations of gerA, gerB and gerC genes (gerX. There are three gene clusters with an ABC-like configuration; ABC gerX1, ABABCB gerX2 and ACxBBB gerX4, and a single CA-B gerX3 gene cluster. Subtypes have been identified for most germinant receptors types, and the individual GerX subunits of each cluster show similar grouping in phylogenetic trees. C. botulinum Group I contained the largest variety of gerX subtypes, with three gerX1, three gerX2 and one gerX3 subtypes, while C. botulinum Group III contained two gerX1 types and one gerX4. C. botulinum Groups II and IV contained a single germinant receptor, gerX3 and gerX1, respectively. It is likely that all four C. botulinum Groups include a SpoVA channel involved in DPA release. The cortex lytic enzymes present in C. botulinum Groups I and III appear to be CwlJ and SleB, while in C. botulinum Groups II and IV, SleC appears to be important.

  3. Early Lotus japonicus root transcriptomic responses to symbiotic and pathogenic fungal exudates

    Directory of Open Access Journals (Sweden)

    Marco eGiovannetti

    2015-06-01

    Full Text Available The objective of this study is to evaluate Lotus japonicus transcriptomic responses to arbuscular mycorrhizal (AM germinated spore exudates (GSE, responsible for activating nuclear Ca2+ spiking in plant root epidermis. A microarray experiment was performed comparing gene expression in Lotus rootlets treated with GSE or water after 24 h and 48 h. The transcriptional pattern of selected genes that resulted to be regulated in the array was further evaluated upon different treatments and timings. In particular, Lotus rootlets were treated with: GSE from the pathogenic fungus Colletotrichum trifolii; short chitin oligomers (acknowledged AM fungal signals and long chitin oligomers (as activators of pathogenic responses. This experimental set up has revealed that AM GSE generates a strong transcriptomic response in Lotus roots with an extensive defense-related response after 24 hours and a subsequent downregulation after 48 hours. A similar subset of defense-related genes resulted to be upregulated also upon treatment with C. trifolii GSE, although with an opposite trend. Surprisingly, long chitin oligomers activated both defense-like and symbiosis-related genes. Among the genes regulated in the microarray, promoter-GUS assay showed that LjMATE1 activates in epidermal cells and root hairs.

  4. On the origin of heterogeneity in (preservation) resistance of Bacillus spores: input for a 'systems' analysis approach of bacterial spore outgrowth.

    Science.gov (United States)

    Hornstra, Luc M; Ter Beek, Alex; Smelt, Jan P; Kallemeijn, Wouter W; Brul, Stanley

    2009-08-31

    Bacterial spores are the ultimate (stress) 'survival capsules'. They allow strains from the Bacillus and Clostridium species to survive harsh environmental conditions. In addition to the decision to enter sporulation the decision to do the reverse (germinate) is also a decisive event after which there is no return. Generally it is observed that the behaviour of spores towards the environment is not homogeneous. In fact in many cases it is even quite heterogeneous, certainly upon subjecting the spores to a thermal stress treatment. Genome information coupled to high resolution single-cell analysis techniques allow us currently to analyse signalling events of individual cells. In the area of food preservation the next challenge is to couple the newly acquired mechanistic data to the physiologically observed heterogeneity in spore behaviour. The current paper will introduce the background of physiological heterogeneity while discussing the molecular processes that likely contribute to the observed heterogeneity in outgrowth. The discussion is set in the framework of contemporary and future needs for single-cell data integration in order to enhance the mechanistic basis of food preservation and spoilage models targeting bacterial spores.

  5. Plant species with extremely small populations (PSESP in China: A seed and spore biology perspective

    Directory of Open Access Journals (Sweden)

    Ellie Merrett Wade

    2016-10-01

    Full Text Available Approximately one fifth of the world's plants are at risk of extinction. Of these, a significant number exist as populations of few individuals, with limited distribution ranges and under enormous pressure due to habitat destruction. In China, these most-at-risk species are described as ‘plant species with extremely small populations’ (PSESP. Implementing conservation action for such listed species is urgent. Storing seeds is one of the main means of ex situ conservation for flowering plants. Spore storage could provide a simple and economical method for fern ex situ conservation. Seed and spore germination in nature is a critical step in species regeneration and thus in situ conservation. But what is known about the seed and spore biology (storage and germination of at-risk species? We have used China's PSESP (the first group listing as a case study to understand the gaps in knowledge on propagule biology of threatened plant species. We found that whilst germination information is available for 28 species (23% of PSESP, storage characteristics are only known for 8% of PSESP (10 species. Moreover, we estimate that 60% of the listed species may require cryopreservation for long-term storage. We conclude that comparative biology studies are urgently needed on the world's most threatened taxa so that conservation action can progress beyond species listing.

  6. Fungi in a changing world: growth rates will be elevated, but spore production may decrease in future climates

    Science.gov (United States)

    Damialis, Athanasios; Mohammad, Aqilah B.; Halley, John M.; Gange, Alan C.

    2015-09-01

    Very little is known about the impact of climate change on fungi and especially on spore production. Fungal spores can be allergenic, thus being important for human health. The aim of this study was to investigate how climate change influences the responsive ability of fungi by simulating differing environmental regimes. Fungal species with high spore allergenic potential and atmospheric abundance were grown and experimentally examined under a variety of temperatures and different nutrient availability. Each represented the average decadal air temperature of the 1980s, 1990s and 2000s in the UK, along with an Intergovernmental Panel on Climate Change (IPCC) climate change scenario for 2100. All tests were run on six fungal species: Alternaria alternata, Aspergillus niger, Botrytis cinerea, Cladosporium cladosporioides, Cladosporium oxysporum and Epicoccum purpurascens. Mycelium growth rate and spore production were examined on each single species and competitive capacity among species combinations in pairs. All fungal species grew faster at higher temperatures, and this was more pronounced for the temperature projection in 2100. Most species grew faster when there was lower nutrient availability. Exceptions were the species with the highest growth rate ( E. purpurascens) and with the highest competition capacity ( A. alternata). Most species (except for E. purpurascens) produced more spores in the richer nutrient medium but fewer as temperature increased. C. cladosporioides was an exception, exponentially increasing its spore production in the temperature of the 2100 scenario. Regarding competitive capacity, no species displayed any significant alterations within the environmental range checked. It is suggested that in future climates, fungi will display dramatic growth responses, with faster mycelium growth and lower spore production, with questions risen on relevant allergen potential.

  7. 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

  8. Gene discovery for the bark beetle-vectored fungal tree pathogen Grosmannia clavigera

    Directory of Open Access Journals (Sweden)

    Robertson Gordon

    2010-10-01

    Full Text Available Abstract Background Grosmannia clavigera is a bark beetle-vectored fungal pathogen of pines that causes wood discoloration and may kill trees by disrupting nutrient and water transport. Trees respond to attacks from beetles and associated fungi by releasing terpenoid and phenolic defense compounds. It is unclear which genes are important for G. clavigera's ability to overcome antifungal pine terpenoids and phenolics. Results We constructed seven cDNA libraries from eight G. clavigera isolates grown under various culture conditions, and Sanger sequenced the 5' and 3' ends of 25,000 cDNA clones, resulting in 44,288 high quality ESTs. The assembled dataset of unique transcripts (unigenes consists of 6,265 contigs and 2,459 singletons that mapped to 6,467 locations on the G. clavigera reference genome, representing ~70% of the predicted G. clavigera genes. Although only 54% of the unigenes matched characterized proteins at the NCBI database, this dataset extensively covers major metabolic pathways, cellular processes, and genes necessary for response to environmental stimuli and genetic information processing. Furthermore, we identified genes expressed in spores prior to germination, and genes involved in response to treatment with lodgepole pine phloem extract (LPPE. Conclusions We provide a comprehensively annotated EST dataset for G. clavigera that represents a rich resource for gene characterization in this and other ophiostomatoid fungi. Genes expressed in response to LPPE treatment are indicative of fungal oxidative stress response. We identified two clusters of potentially functionally related genes responsive to LPPE treatment. Furthermore, we report a simple method for identifying contig misassemblies in de novo assembled EST collections caused by gene overlap on the genome.

  9. Fungal Eye Infections

    Science.gov (United States)

    ... Treatment & Outcomes Statistics More Resources Fungal Nail Infections Histoplasmosis Definition Symptoms People at Risk & Prevention Sources Diagnosis & ... CDC at Work Global Fungal Diseases Cryptococcal Meningitis Histoplasmosis ... Resistance Resources Laboratory Submission Information Reportable Fungal ...

  10. iTRAQ and RNA-Seq Analyses Provide New Insights into Regulation Mechanism of Symbiotic Germination of Dendrobium officinale Seeds (Orchidaceae).

    Science.gov (United States)

    Chen, Juan; Liu, Si Si; Kohler, Annegret; Yan, Bo; Luo, Hong Mei; Chen, Xiao Mei; Guo, Shun Xing

    2017-06-02

    Mycorrhizal fungi colonize orchid seeds and induce germination. This so-called symbiotic germination is a critical developmental process in the lifecycle of all orchid species. However, the molecular changes that occur during orchid seed symbiotic germination remain largely unknown. To better understand the molecular mechanism of orchid seed germination, we performed a comparative transcriptomic and proteomic analysis of the Chinese traditional medicinal orchid Dendrobium officinale to explore the change in protein expression at the different developmental stages during asymbiotic and symbiotic germination and identify the key proteins that regulate the symbiotic germination of orchid seeds. Among 2256 identified plant proteins, 308 were differentially expressed across three developmental stages during asymbiotic and symbiotic germination, and 229 were differentially expressed during symbiotic germination compared to asymbiotic development. Of these, 32 proteins were coup-regulated at both the proteomic and transcriptomic levels during symbiotic germination compared to asymbiotic germination. Our results suggest that symbiotic germination of D. officinale seeds shares a common signaling pathway with asymbiotic germination during the early germination stage. However, compared to asymbiotic germination, fungal colonization of orchid seeds appears to induce higher and earlier expression of some key proteins involved in lipid and carbohydrate metabolism and thus improves the efficiency of utilization of stored substances present in the embryo. This study provides new insight into the molecular basis of orchid seed germination.

  11. Spore surface glycoproteins of Colletotrichum lindemuthianum are recognized by a monoclonal antibody which inhibits adhesion to polystyrene.

    Science.gov (United States)

    Hughes, H B; Carzaniga, R; Rawlings, S L; Green, J R; O'Connell, R J

    1999-08-01

    Conidia (spores) of Colletotrichum lindemuthianum, a fungal plant pathogen causing bean anthracnose, adhere to the aerial parts of host plants to initiate the infection process. These spores possess a fibrillar 'spore coat' as well as a cell wall. In a previous study a mAb, UB20, was raised that recognized glycoproteins on the spore surface. In this study UB20 was used to localize and characterize these glycoproteins and to investigate their possible role in adhesion. Glycoproteins recognized by UB20 were concentrated on the outer surface of the spore coat and, to a lesser extent, at the plasma membrane/cell wall interface. Extraction of spores with hot water or 0.2% SDS resulted in removal of the spore coat. Western blotting with UB20 showed that a relatively small number of glycoproteins were extracted by these procedures, including a major component at 110 kDa. Biotinylation of carbohydrate moieties, together with cell fractionation, confirmed that these glycoproteins were exposed at the surface of the spores. In adhesion assays, > 90% of ungerminated conidia attached to polystyrene Petri dishes within 30 min. UB20 IgG at low concentrations inhibited attachment in an antigen-specific manner. This suggests that the glycoproteins recognized by this mAb may function in the initial rapid attachment of conidia to hydrophobic substrata. Polystyrene microspheres bound selectively to the 110 kDa glycoprotein in Western blots, providing further evidence that this component could mediate interactions with hydrophobic substrata.

  12. 低温对葡萄孢菌( Botrytis cinerea )菌丝生长和孢子萌发以及对贮藏菊苣侵染力的影响%EFFECTS OF LOW TEMPERATURE ON MYCELIAL GROWTH AND SPORE GERMINATION OF Botrytis cinerea IN VITRO AND ON ITS INFECTIVITY TO STORED CHICORY

    Institute of Scientific and Technical Information of China (English)

    田世平

    2001-01-01

    本文主要研究葡萄孢菌(Botrytis cinerea)在20、10、4、2、0、—2和—4℃下菌丝生长和孢子萌发的情况,以及在同样温度下对菊苣(Cichorium intybus L.)致病力的影响。尽管在PDA培养基上0℃以下低温明显地抑制菌丝生长和推迟孢子的萌发时间,但葡萄孢菌仍能在—4℃下14 d后达到100%的萌发率,24周后菌落的生长直径为10 mm。用Botrytis cinerea孢子接种的菊苣在—2℃下6周以前的发病率较低,在—4℃下8周以前没有病害发生,但随着贮藏时间的延长,发病率逐渐上升,12周后腐烂率达到77%和71%,病害严重程度指数分别为37和31。菊苣贮藏在—2℃和—4℃下后期腐烂率的快速增加可能与此时菊苣产生冷害有关。%The effects of low temperature ranging from 20℃ to —4℃ on mycelial growth, the conidial germination of Botrytis cinerea in culture and its infectivity to stored chicory (Cichorium intybus L. ) were investigated. Although temperatures below 0℃ could inhibit the mycelial growth and delay the conidial germination, B. cinerea was able to grow and germinate on PDA and to infect chicory even at —4℃. Germination rate reached 100% after 14 days and mycelial diameter was 10 mm after 24 weeks at such temperature. No decay was found in chicory kept at —4℃ before 8 weeks and there was very low disease incidence in chicory stored at —2℃ in 6 weeks of storage. After 12 weeks in storage, disease incidence reached 77% and 71% with a disease severity score of 37 and 31, respectively, which may be related partly to freezing injury of chicory stored at such temperatures.

  13. Inhibitory effects of nisin-coated multi-walled carbon nanotube sheet on biofilm formation from Bacillus anthracis spores