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Yuniarti, Ating, Nasrullah Bai Arifin, Muhammad Fakhri, and Anik M. Hariati. "Spore production and sporulation efficacy of Bacillus subtilis under different source of manganese supplementation [Produksi Spora dan Efisiensi Sporulasi Bacillus subtilis dengan Suplementasi Mangan dari Sumber yang Berbeda]." Jurnal Ilmiah Perikanan dan Kelautan 11, no. 2 (October 25, 2019): 51. http://dx.doi.org/10.20473/jipk.v11i2.15250.
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AbstractBacillus is a species widely used as a probiotic in the aquaculture industry. The Bacillus spores have more advantages than their vegetative ones, and an addition of minerals such as calcium, magnesium, and manganese can improve the spore production. The purpose of this study was to determine the effect of different sources of manganese on the production and sporulation efficacy of B. subtilis SB3. The sources of manganese used in this study were manganese chloride (MnCl2) and manganese sulfate (MnSO4) at the concentration of 10 mM. Media without manganese supplementation was used as a control. The results showed that there was a significant effect of different manganese sources on the spore production of B. subtilis SB3. The highest spore production was found in media with MnCl2 supplementation with the total spore of 8.77 x 107 spores. mL-1. However, spore production with MnSO4 supplementation was still higher (22.7%) compared to that without manganese supplementation. The decrease in spore production with MnSO4 supplementation was possible due to the sulfate inhibition. The high spore production in media with MnCl2 supplementation was also preceded by the high production of vegetative cells from B. subtilis SB3 (2.54 x 108 cells. mL-1). The results indicated that manganese could stimulate both vegetative cell growth and its spores. The highest sporulation efficacy (35%) was also achieved in media with MnCl2 supplementation. On the other hand, the germination rate of B. subtilis SB3 spores was not influenced by manganese supplementation.Abstrak Bacillus adalah species yang banyak digunakan sebagai probiotik pada industri akuakultur. Dalam bentuk spora, species ini lebih banyak mempunyai kelebihan dibandingkan dalam bentuk vegetatifnya dan peningkatan produksi sporanya dapat dilakukan dengan penambahan mineral seperti kalsium, magnesium dan mangan. Tujuan penelitian ini adalah untuk mengetahui pengaruh sumber mangan yang berbeda terhadap produksi dan efisiensi sporulasi B. subtilis SB3 indigenous akuatik. Sumber mangan yang dipakai dalam penelitian ini adalah mangan klorida (MnCl2) dan mangan sulfat (MnSO4) sebanyak 10 mM dan sebagai kontrol digunakan media tanpa suplementasi mangan. Hasil penelitian menunjukkan bahwa terdapat pengaruh yang nyata penggunaan sumber mangan yang berbeda terhadap produksi spora. Produksi spora tertinggi didapatkan pada media dengan suplementasi MnCl2 sebanyak 8,77 x 107 spora. mL-1. Sedangkan produksi spora dengan suplementasi MnSO4 juga masih lebih tinggi (22,7%) dibandingkan tanpa suplementasi magan. Penurunan produksi spora pada media dengan penambahan mangan sulfat diduga karena adanya penghambatan oleh sulfat. Tingginya produksi spora pada media dengan suplementasi MnCl2 sebelumnya juga didahului dengan tingginya produksi sel vegetatif dari B. subtilis SB3 (2,54 x 108sel. mL-1). Hal ini menunjukkan bahwa mangan dapat menstimulasi baik pertumbuhan sel vegetatif dan sporanya. Efisiensi sporulasi tertinggi juga dicapai pada media dengan suplementasi MnCl2 sebesar 35%. Di sisi lain, kemampuan germinasi spora B. subtilis SB3 tercatat sama dan tidak dipengaruhi oleh suplementasi mangan.
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Burrows, Rhoda L., and Francis L. Pfleger. "Arbuscular mycorrhizal fungi respond to increasing plant diversity." Canadian Journal of Botany 80, no. 2 (February 1, 2002): 120–30. http://dx.doi.org/10.1139/b01-138.
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The effect of plant diversity (1, 2, 8, or 16 species) on arbuscular mycorrhizal fungi (AMF) was assessed at the Cedar Creek Long-Term Ecological Research site at East Bethel, Minnesota, from 1997 to 1999. At each of the five samplings, AMF in 16-species plots produced from 30 to 150% more spores and from 40 to 70% greater spore volumes than AMF in one-species plots. Regressions of spore numbers and volumes with percent plant cover, plant diversity, and soil NO3 as independent variables suggest that midsummer plot soil NO3 was the best single predictor of AMF spore production in these plots. Plant diversity influenced spore volume in four samplings and spore numbers in the first three samplings. Plant cover was predictive of spore volume throughout the experiment but of spore number only in the first year. Sporulation by larger-spored AMF species (Gigaspora spp. and Scutellospora spp.) increased significantly with increasing plant diversity, while sporulation of the smaller-spored species varied in response to host diversity. Spore numbers of several AMF species were consistently negatively correlated and none positively correlated with midseason soil NO3 concentrations, demonstrating the adaptation of these AMF species to nitrogen-limited conditions.Key words: mycorrhiza, community, grassland, sporulation, nitrogen, specificity.
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Sofiyanti, Nery, and Putri Handayani Harahap. "INVENTARISASI DAN KAJIAN PALINOLOGI JENIS-JENIS TUMBUHAN PAKU (PTERODOFITA) EPIFIT DI KAWASAN UNIVERSITAS RIAU, PROVINSI RIAU." Jurnal Biologi Tropis 19, no. 2 (October 19, 2019): 214. http://dx.doi.org/10.29303/jbt.v19i2.1266.
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Abstrak : Tumbuhan paku (Pteridofita) epifit banyak di jumpai di kawasan Universitas Riau. Karakteristik spora pada tumbuhn apaku memegang peranan penting dalam kajian taksonomi. Penelitian ini bertujuan untuk mengidentifikasi jenis-jenis pteridofita epifit di kawasan ini dan mengkarakterisasi sporanya. Metode pengambilan sampel dilakukan menggunakan metode eksplorasi. Setiap jenis yang dijumpai didokumentasikan, dibuat herbarium, dideskripsi dan diidentifikasi. Spora dikoleksi dari daun yang sudah dewasa dan dibuat preparat menggunakan metode asetolisis. Preparat spora diamati dan didokumentasikan menggunakan mikroskop digital. Data yang diperoleh kemudian disajikan dalam bentuk gambar dan tabel serta dianalisis secara deskriptif. Hasil inventarisasi paku epifit di kawasan Universitas Riau mengidentifikasi 18 jenis paku epifit, yang tergolong ke dalam 6 famili yaitu Aspleniaceae, Davalliaceae, Nephrolepidaceae, Polypodiaceae Pteridaceae and Thelypteridaceae. Namun kajian palinologi hanya dilakukan pada 11 jenis yang sudah menghasilkan spora. Hasil pengamatan spora menunjukan bahwa semua jenis paku epifit mempunyai tipe dasar spora monolete, berbentuk ginjal dan hanya mempunyai satu laesura pada bagian ventral. Ukuran spora yang dijumpai adalah besar dan sangat besar, dengan ornamentasi permukaan Lohpat, verukat berpapila verukat, tuberkulat, ekinat pendek dan ekinat panjang. Morfologi spora yang ditemukan pada penelitian ini menunjukan karakteristik yang berbeda pada setiap jenis. Namun masih perlu dilanjutkan pengamatan menggunakan Scanning Electron Microscopy untuk mendapatkan oramentasi lebih detilKata kunci : paku epifit, palinologi, spora, monolete, UNRI Abstract : Ephypitic ferns are commonly found in University of Riau area. Spore characteristics play important role in taxonomical words. This study aimed to identify ephypitic pteridophyte species from this area and characterize their spore. Samples were collected using exploration method, and were then documented, prepared for herbarium, described and identified. Spore grains were collected from mature leaves and prepared by using acetolysis method. The spores were then observed and documented using digital microscope. Data were presented in figures and tables and describtively analized. The inventory of ephypitic ferns from University of Riau area identified a total of 18 fern species belong to 6 families, i.e. Aspleniaceae, Davalliaceae, Nephrolepidaceae, Polypodiaceae, Pteridaceae and Thelypteridaceae. Palinologycal study had been carried out from 11 species that produced spore. We observed the basic spore type of examined ephypitic ferns, monolete, with reniform shape and one laesura at the ventral part. The size of spore observed were big and very big spore, with surface ornamentation Lohpate, papillous verucate, verucate, tuberculate,, short echinate and long echinate. Spore morphology observed in this study showed the characteristic among the examined species. The further study using Scanning Electron Microscopy is neccesary to obtain detail spore ornamentation.Keywords: ephypitic fern, palynology, spore, monolete, UNRI
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PEREIRA, CAMILLA M. R., LEONOR C. MAIA, IVÁN SÁNCHEZ-CASTRO, JAVIER PALENZUELA, DANIELLE K. A. SILVA, RADKA SUDOVÁ, ZUZANA SÝKOROVÁ, et al. "Acaulospora papillosa, a new mycorrhizal fungus from NE Brazil, and Acaulospora rugosa from Norway." Phytotaxa 260, no. 1 (May 9, 2016): 14. http://dx.doi.org/10.11646/phytotaxa.260.1.2.
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A new arbuscular mycorrhizal species, Acaulospora papillosa, was isolated from the biological reserve ‘Saltinho’ within a coastal tropical Atlantic forest of the ‘Mata Atlântica’ biome in Pernambuco State of Northeastern Brazil. It was trapped and propagated as single species cultures on Zea mays. The spores are yellow white to light yellow to creamy, globose to subglobose, 69–100(–110) × 65–93(–101) µm. The spore surface is roughened as crowded with fine papillae, which are formed on the outermost, evanescent to semi-persistent spore wall layer. These papillae may disintegrate or completely disappear as the spores age and the layer becomes completely evanescent. Phylogenetically, the fungus clusters together with several small-spored Acaulospora species having smooth spore surfaces, such as A. delicata, A. longula, A. morrowiae and A. mellea. In the Acaulospora clade, A. papillosa is the third taxon known to have a roughened spore surface, in addition to A. dilatata and A. rugosa. The phylogenetic placement of A. rugosa is provided, together with colored illustrations of the spore morphology. The isolation of A. papillosa from such protected nature reserves as ‘Saltinho’ further supports the need to protect these areas and determine the biodiversity of beneficial microorganisms.
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Craven, S. E., and L. C. Blankenship. "Changes in the hydrophobic characteristics of Clostridium perfringens spores and spore coats by heat." Canadian Journal of Microbiology 33, no. 9 (September 1, 1987): 773–76. http://dx.doi.org/10.1139/m87-132.
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The hydrophobic characteristics of Clostridium perfringens NCTC 8679 spores were demonstrated by adherence to toluene in a toluene–aqueous partition system. Spores and spore coat preparations were hydrophobic. Vegetative cells and spores extracted with a dithiothreitol – sodium dodecyl sulfate treatment known to remove spore coats were not hydrophobic. A heat activation treatment (75 °C for 20 min) which promotes more rapid spore germination increased the hydrophobicity of intact spores and decreased that of isolated spore coats. The hydrophobic changes were reversed by washing and stabilized by 0.5% glutaraldehyde. Heat-induced hydrophobic changes were observed in spore coats prepared from spores that were preheated and washed before rupturing in a buffer containing glutaraldehyde. These results suggest the occurrence of a heat-induced change in the spore coat (possibly in the conformation of a macromolecule) which was stable only within the architectural confines of the intact spore.
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Kauserud, Håvard, Einar Heegaard, Rune Halvorsen, Lynne Boddy, Klaus Høiland, and Nils Chr Stenseth. "Mushroom's spore size and time of fruiting are strongly related: is moisture important?" Biology Letters 7, no. 2 (October 20, 2010): 273–76. http://dx.doi.org/10.1098/rsbl.2010.0820.
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Most basidiomycete fungi produce annual short-lived sexual fruit bodies from which billions of microscopic spores are spread into the air during a short time period. However, little is known about the selective forces that have resulted in some species fruiting early and others later in the fruiting season. This study of relationships between morphological and ecological characteristics, climate factors and time of fruiting are based upon thorough statistical analyses of 66 520 mapped records from Norway, representing 271 species of autumnal fruiting mushroom species. We found a strong relationship between spore size and time of fruiting; on average, a doubling of spore size (volume) corresponded to 3 days earlier fruiting. Small-spored species dominate in the oceanic parts of Norway, whereas large-spored species are typical of more continental parts. In separate analyses, significant relationships were observed between spore size and climate factors. We hypothesize that these relationships are owing to water balance optimization, driven by water storage in spores as a critical factor for successful germination of primary mycelia in the drier micro-environments found earlier in the fruiting season and/or in continental climates.
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Tu, Zhiwei, Wishwas R. Abhyankar, Bhagyashree N. Swarge, Nicole van der Wel, Gertjan Kramer, Stanley Brul, and Leo J. de Koning. "Artificial Sporulation Induction (ASI) by kinA Overexpression Affects the Proteomes and Properties of Bacillus subtilis Spores." International Journal of Molecular Sciences 21, no. 12 (June 17, 2020): 4315. http://dx.doi.org/10.3390/ijms21124315.
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To facilitate more accurate spore proteomic analysis, the current study focuses on inducing homogeneous sporulation by overexpressing kinA and assesses the effect of synchronized sporulation initiation on spore resistance, structures, the germination behavior at single-spore level and the proteome. The results indicate that, in our set up, the sporulation by overexpressing kinA can generate a spore yield of 70% within 8 h. The procedure increases spore wet heat resistance and thickness of the spore coat and cortex layers, whilst delaying the time to spore phase-darkening and burst after addition of germinant. The proteome analysis reveals that the upregulated proteins in the kinA induced spores, compared to spores without kinA induction, as well as the ‘wildtype’ spores, are mostly involved in spore formation. The downregulated proteins mostly belong to the categories of coping with stress, carbon and nitrogen metabolism, as well as the regulation of sporulation. Thus, while kinA overexpression enhances synchronicity in sporulation initiation, it also has profound effects on the central equilibrium of spore formation and spore germination, through modulation of the spore molecular composition and stress resistance physiology.
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Raju, N. B., and D. D. Perkins. "Expression of meiotic drive elements Spore killer-2 and Spore killer-3 in asci of Neurospora tetrasperma." Genetics 129, no. 1 (September 1, 1991): 25–37. http://dx.doi.org/10.1093/genetics/129.1.25.
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Abstract It was shown previously that when a chromosomal Spore killer factor is heterozygous in Neurospora species with eight-spored asci, the four sensitive ascospores in each ascus die and the four survivors are all killers. Sk-2K and Sk-3K are nonrecombining haplotypes that segregate with the centromere of linkage group III. No killing occurs when either one of these killers is homozygous, but each is sensitive to killing by the other in crosses of Sk-2K x Sk-3K. In the present study, Sk-2K and Sk-3K were transferred by recurrent backcrosses from the eight-spored species Neurospora crassa into Neurospora tetrasperma, a pseudohomothallic species which normally makes asci with four large spores, each heterokaryotic for mating type and for any other centromere-linked genes that are heterozygous in the cross. The action of Sk-2K and Sk-3K in N. tetrasperma is that predicted from their behavior in eight-spored species. A sensitive nucleus is protected from killing if it is enclosed in the same ascospore with a killer nucleus. Crosses of Sk-2K x Sk-2S, Sk-3K x Sk-3S, and Sk-sK x Sk-3K all produce four-spored asci that are wild type in appearance, with the ascospores heterokaryotic and viable. The Eight-spore gene E, which shows variable penetrance, was used to obtain N. tetrasperma asci in which two to eight spores are small and homokaryotic. When killer and sensitive alleles are segregating in the presence of E, only those ascospores that contain a killer allele survive. Half of the small ascospores are killed. In crosses of Sk-2K x Sk-3K (with E heterozygous), effectively all small ascospores are killed. The ability of N. tetrasperma to carry killer elements in cryptic condition suggests a possible role for Spore killers in the origin of pseudohomothallism, with adoption of the four-spored mode restoring ascospore viability of crosses in which killing would otherwise occur.
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Gangi, Victor J., Ira E. Leonard, Allison A. Rodriguez, and Aaron B. Margolin. "Evaluation of Materials as Bacterial Spore Carriers for Testing Disinfectants." Journal of AOAC INTERNATIONAL 80, no. 6 (November 1, 1997): 1361–67. http://dx.doi.org/10.1093/jaoac/80.6.1361.
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Abstract Prototype objects made of steel, glass, and various polymers were evaluated in relation to currently used objects made of silk suture and porcelain for their use as bacterial spore carriers for testing the sporicidal activity of disinfectants. The carriers were inoculated with spores of Bacillus subtilis. Spore retention was determined by detachment from the carriers by sonication and rinsing. Inoculated carriers were exposed to 2.5N HCI and 2.5% glutaraldehyde solutions to determine the effect of carrier material on spore inactivation. Carriers with the highest and lowest spore retention were steel-silicone mix carriers (1.7 × 106 spores/carrier) and polyvinylchloride cylinders (3.8 × 105 spores/carrier), respectively. Spore adhesion to carrier objects was not directly proportional to carrier surface area. Spores on silk sutures, grooved steel, and Teflon carriers survived longest in HCI solution. Spores on Teflon, grooved stainless steel, and glass cylinders survived longest in glutaraldehyde solution. In chemical and spore adhesion tests, no significant statistical differences were found between novel carrier materials and current spore carrier materials. The methods used for evaluating carrier materials were reliable and repeatable.
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Fitriana, Yuyun, Radix Suharjo, I. Gede Swibawa, Purnomo ., Puji Lestari, and Eryka Merdiana. "INFLUENCE OF CULTURE MEDIUM ON THE SPORULATION AND VIABILITY OF ASPERGILLUS SPP. AND TALAROMYCES SPP. ENTOMOPATHOGENIC FUNGI." JURNAL HAMA DAN PENYAKIT TUMBUHAN TROPIKA 18, no. 1 (August 2, 2018): 12. http://dx.doi.org/10.23960/j.hptt.11812-22.
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Influence of Culture Medium on the Sporulation and Viability of Aspergillus spp. and Talaromyces spp. Entomopathogenic Fungi. The purpose of this study was to determine the effect of three kinds of cultures media on the spore production and viability of Aspergillus spp. (AS1, 6, 7, 9) and Talaromyces spp. (AS2–5, 8, 10) entomopathogenic fungi. This study was arranged using Factorial-Completely Randomized Design (CRD) with 2 factors and 3 replications. The first factor was three kinds of cultures media (potato dextrose agar (PDA), corn meal agar (CMA), and sabouraud dextrose agar (SDA)) and the second one was isolates of Aspergillus spp. Or Talaromyces spp.. Data of spore production and spore viability were tested using ANOVA and if there was significantly difference, the data then further analyzed using Tukey‘s Honestly Significant Difference (HSD) test at 5% of significant level. The spore production of Aspergillus spp. were in the range of 0.58 - 14.27 x 108 spores mL-1 (PDA); 0.28 – 2.68 x 108 spores mL-1 (SDA) and 1.85 - 5.33 x 108 spores mL-1 (CMA). The highest spore production was achieved by AS1 isolate that was grown on PDA media. The spore produced by Talaromyces spp. were in the range of 2.15 – 28.62 x108 spores mL-1 (PDA); 0.28 – 29.43 x108 spores mL-1 (SDA); and 1.88 – 16.63 x108 spores mL-1 (CMA). The highest spore production was produced by AS8 isolate which were cultured on PDA. The spore viability among isolates of the two entomopathogenic fungi were not significantly different. The spore viability of Aspergillus spp. was in the range of 95.10 – 97.66% (PDA), 94.02 – 98.45% (SDA) and 92.86 – 98.20% (CMA). The spore viability of Talaromyces spp. was in the range of 95.83 – 100% (PDA), 85.83 – 100% (SDA), and 90.75 – 100% (CMA). Culture medium influenced spore production but not the spore viability. The best culture media used for spore production of both of the entomopathogenic fungi was PDA media.
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Nakano, Shota, Qi Gao, Tadanori Aimi, and Norihiro Shimomura. "Rhizopogon roseolus basidiospore germination decreases as the fruiting bodies mature and the spore wall becomes more complex." Botany 94, no. 4 (April 2016): 311–20. http://dx.doi.org/10.1139/cjb-2015-0198.
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Rhizopogon roseolus (Corda) Th. Fr. is a basidiomycete truffle that is considered edible. Its gleba changes color from white to beige to brown as it matures. Although ultrastructural changes in the spore wall have been linked to the maturation of the fruiting body, little is known regarding the relationship between spore germination success and the ultrastructure of the spore wall. We examined spore germination on agar plates and analyzed the spore wall ultrastructure using transmission electron microscopy (TEM). Fruiting bodies, collected from a pine forest, were classified into three developmental stages based on gleba color, and the germination success was evaluated at each stage. Variability in the spore germination rate was observed between individual fruiting bodies. The peak germination rate was recorded for the spores from the fruiting bodies in the beige glebal stage, and the rate was lower in the brown glebal stage. When spore wall structures were studied using TEM, the spore wall was found to be multilayered upon maturation of the fruiting body. The spores of the beige glebal stage showed three types of spore walls, namely two-layered, three-layered, and four-layered spore walls. On the other hand, the spores of the brown glebal stage showed predominantly four-layered spore walls. These results indicate that spore germination of R. roseolus decreases as the fruiting body matures and the spore wall becomes more complex.
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Martínez-Bracero, Moisés, Emma Markey, Jerry Hourihane Clancy, John Sodeau, and David J. O’Connor. "First Long-Time Airborne Fungal Spores Study in Dublin, Ireland (1978–1980)." Atmosphere 13, no. 2 (February 13, 2022): 313. http://dx.doi.org/10.3390/atmos13020313.
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Ambient fungal spores within the atmosphere can contribute to a range of negative human, animal and plant health conditions and diseases. However, trends in fungal spore seasonality, species prevalence, and geographical origin have been significantly understudied in Ireland. Previously unpublished data from the late 1970s have recently been collected and analysed to establish historical fungal spore trends/characteristics for Dublin. Historical spore concentrations were largely dominated by Alternaria, Ascospores, Basidiospores, Botrytis, Cladosporium, Erysiphe and Rusts. The main fungal spore season for Dublin commenced in April with the fructification of Scopulariopsis and Ganoderma. However, the vast majority of other spore types did not reach peak spore release until late summer. The correlation between ambient spore concentration, and meteorological parameters was examined using Multivariable Regression Tree (MRT) analysis. The notable correlations found for fungal spore concentrations tended to involve temperature-based parameters. The use of a non-parametric wind regression was also employed to determine the potential geographical origin of ambient fungal spores. The impact of wind direction, and high windspeed on fungal spores was established, ultimately highlighting the importance of studying and monitoring fungal spores within Ireland, rather than attempting to rely on data from other regions, as most fungal spores collected in Dublin appeared to originate from within the island.
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Riesenman, Paul J., and Wayne L. Nicholson. "Role of the Spore Coat Layers in Bacillus subtilis Spore Resistance to Hydrogen Peroxide, Artificial UV-C, UV-B, and Solar UV Radiation." Applied and Environmental Microbiology 66, no. 2 (February 1, 2000): 620–26. http://dx.doi.org/10.1128/aem.66.2.620-626.2000.
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ABSTRACT Spores of Bacillus subtilis possess a thick protein coat that consists of an electron-dense outer coat layer and a lamellalike inner coat layer. The spore coat has been shown to confer resistance to lysozyme and other sporicidal substances. In this study, spore coat-defective mutants of B. subtilis (containing thegerE36 and/or cotE::cat mutation) were used to study the relative contributions of spore coat layers to spore resistance to hydrogen peroxide (H2O2) and various artificial and solar UV treatments. Spores of strains carrying mutations in gerE and/or cotE were very sensitive to lysozyme and to 5% H2O2, as were chemically decoated spores of the wild-type parental strain. Spores of all coat-defective strains were as resistant to 254-nm UV-C radiation as wild-type spores were. Spores possessing thegerE36 mutation were significantly more sensitive to artificial UV-B and solar UV radiation than wild-type spores were. In contrast, spores of strains possessing thecotE::cat mutation were significantly more resistant to all of the UV treatments used than wild-type spores were. Spores of strains carrying both the gerE36 andcotE::cat mutations behaved likegerE36 mutant spores. Our results indicate that the spore coat, particularly the inner coat layer, plays a role in spore resistance to environmentally relevant UV wavelengths.
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Holland, R. J., T. S. Gunasekera, K. L. Williams, and K. M. H. Nevalainen. "Ultrastructure and properties of Paecilomyces lilacinus spores." Canadian Journal of Microbiology 48, no. 10 (October 1, 2002): 879–85. http://dx.doi.org/10.1139/w02-083.
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Strains of the filamentous soil fungus Paecilomyces lilacinus are currently being developed for use as biological control agents against root-knot, cyst, and other plant-parasitic nematodes. The inoculum applied in the field consists mainly of spores. This study was undertaken to examine the size, ultrastructure, and rodlet layers of P. lilacinus spores and the effect of the culture method on structural and functional spore properties. A rodlet layer was identified on aerial spores only. Other differences noted between aerial spores and those produced in submerged culture included the size and appearance of spores and thickness of spore coat layers when examined with transmission electron microscopy. The two spore types differed in UV tolerance, with aerial spores being less sensitive to environmentally relevant UV radiation. Also, viability after drying and storage was better with the aerial spores. Both spore types exhibited similar nematophagous ability.Key words: Paecilomyces lilacinus, fungal spores, rodlet layer, spore ultrastructure, UV sensitivity, biological control.
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Fukunishi, Kana, Kana Miyakubi, Mitsuko Hatanaka, Natsumi Otsuru, Aiko Hirata, Chikashi Shimoda, and Taro Nakamura. "The fission yeast spore is coated by a proteinaceous surface layer comprising mainly Isp3." Molecular Biology of the Cell 25, no. 10 (May 15, 2014): 1549–59. http://dx.doi.org/10.1091/mbc.e13-12-0731.
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The spore is a dormant cell that is resistant to various environmental stresses. As compared with the vegetative cell wall, the spore wall has a more extensive structure that confers resistance on spores. In the fission yeast Schizosaccharomyces pombe, the polysaccharides glucan and chitosan are major components of the spore wall; however, the structure of the spore surface remains unknown. We identify the spore coat protein Isp3/Meu4. The isp3 disruptant is viable and executes meiotic nuclear divisions as efficiently as the wild type, but isp3∆ spores show decreased tolerance to heat, digestive enzymes, and ethanol. Electron microscopy shows that an electron-dense layer is formed at the outermost region of the wild-type spore wall. This layer is not observed in isp3∆ spores. Furthermore, Isp3 is abundantly detected in this layer by immunoelectron microscopy. Thus Isp3 constitutes the spore coat, thereby conferring resistance to various environmental stresses.
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Kishi, Y., C. Clements, D. C. Mahadeo, D. A. Cotter, and M. Sameshima. "High levels of actin tyrosine phosphorylation: correlation with the dormant state of Dictyostelium spores." Journal of Cell Science 111, no. 19 (October 1, 1998): 2923–32. http://dx.doi.org/10.1242/jcs.111.19.2923.
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Upon removal of nutrients, the amoebae of the cellular slime mold Dictyostelium discoideum differentiate into dormant spores which survive starvation stress. In this study, we demonstrate that half of the actin molecules in the spores are tyrosine-phosphorylated. The phosphorylated actin is distributed around immobile crenate mitochondria and vesicles, as well as in the cytoplasm of the spores. The actin isolated from spore lysates contains phosphorylated and unphosphorylated forms at the same molar ratio as that of the original whole spore lysate. Under actin polymerizing conditions they form actin filaments and then they are completely depolymerized under actin depolymerizing conditions, indicating that tyrosine phosphorylation of actin may not prohibit actin polymerization nor stimulate depolymerization. The phosphorylation levels increase at the end of the culmination stage when spores have matured morphologically and physiologically, and reach maximum levels after an additional 12 hours of development. The levels are stable for 20 days following spore maturation, and decline to undetectable levels within the next 10 days. Spores having high levels of phosphorylation show high viability, and vice versa. Following activation of spores with nutrient medium containing spore germination promoters, the phosphorylation levels quickly decrease with a half-life of about 5 minutes. After 20 minutes spores begin to swell. At this later time, most of the phosphorylated actin already has been dephosphorylated. Also, in heat-activated spores actin dephosphorylation occurs prior to spore swelling. However, addition of phosphatase inhibitors following heat-activation, prevented spore swelling and dephosphorylation of actin. Our data indicate that the high levels of actin tyrosine phosphorylation, specific to the spore stage, may be required for maintaining dormancy to withstand starvation stress. The rapid dephosphorylation of actin leads to a reactivated dynamic actin system which participates in spore swelling, vesicle movement, and mitochondrial shape changes during the spore germination process.
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Jiménez-Zapata, Diana L., Manuela Quiroga-Pérez, Manuela Quiroz-Yepes, Alejandro Marulanda-Tobón, Javier C. Álvarez, and Sandra Mosquera-López. "Development of a Method for Detecting and Estimating Moniliophthora roreri Spore Loads Based on Spore Traps and qPCR." Journal of Fungi 9, no. 1 (December 28, 2022): 47. http://dx.doi.org/10.3390/jof9010047.
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Frosty pod rot, caused by Moniliophthora roreri, is the most damaging disease of cacao in Latin America and, to better comprehend its epidemiology, we must understand its dissemination and proliferation. However, we do not know how M. roreri spores loads fluctuate in time and space due to the lack of a reliable technique to quantify M. roreri spores in the fields. Therefore, we developed a method that relies on spore traps and qPCR to detect and quantify M. roreri spore loads. This study demonstrated that the qPCR protocol can detect down to 0.025 ng of M. roreri DNA and quantify between 0.006 ng and 60 ng. Moreover, it demonstrated that qPCR protocol can detect and quantify DNA extracted from spore suspension and spore traps containing at least 2.9 × 104 M. roreri spores. However, the variability of the estimates for spore samples was high. Finally, we described a spore-trap device designed to carry spore traps in the field. The qPCR protocol and spore-trap device here developed will help in the understanding of the M. roreri dissemination patterns since they can be used to assess the environmental loads of M. roreri spore in cacao fields.
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KARUNARATNE, ANJANI, and LLOYD B. BULLERMAN. "Interactive Effects of Spore Load and Temperature on Aflatoxin Production1." Journal of Food Protection 53, no. 3 (March 1, 1990): 227–29. http://dx.doi.org/10.4315/0362-028x-53.3.227.
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The relationship between initial spore load of an aflatoxigenic mold and subsequent growth and aflatoxin production were studied at 28 and 35°C. The initial spore loads ranges <101 to 107 spores/ml. As the spore level increased, visible growth appeared sooner and was more extensive. Growth, determined by viable plate counts, indicated that maximum growth in all the treatments reached 109 CFU/g, irrespective of the initial spore load. Mycelial growth and sporulation occurred faster at 35°C at all spore levels than at 28°C. At 28°C, unusually high amounts of aflatoxin Bl (380 ug/g) were produced when 103 spores were inoculated into 50 g rice, while the lower and the higher spore levels produced comparatively lower levels of aflatoxin. At 35°C the lowest spore level (<101 spores) produced the highest amount of aflatoxin B1 (62 μg/g). The higher spore levels at 35°C either did not result in any aflatoxin formation, or the amounts produced were negligible. At 35°C many fluorescing compounds other than aflatoxins were detected.
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Botts, Michael R., Steven S. Giles, Marcellene A. Gates, Thomas R. Kozel, and Christina M. Hull. "Isolation and Characterization of Cryptococcus neoformans Spores Reveal a Critical Role for Capsule Biosynthesis Genes in Spore Biogenesis." Eukaryotic Cell 8, no. 4 (January 30, 2009): 595–605. http://dx.doi.org/10.1128/ec.00352-08.
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ABSTRACT Spores are essential particles for the survival of many organisms, both prokaryotic and eukaryotic. Among the eukaryotes, fungi have developed spores with superior resistance and dispersal properties. For the human fungal pathogens, however, relatively little is known about the role that spores play in dispersal and infection. Here we present the purification and characterization of spores from the environmental fungus Cryptococcus neoformans. For the first time, we purified spores to homogeneity and assessed their morphological, stress resistance, and surface properties. We found that spores are morphologically distinct from yeast cells and are covered with a thick spore coat. Spores are also more resistant to environmental stresses than yeast cells and display a spore-specific configuration of polysaccharides on their surfaces. Surprisingly, we found that the surface of the spore reacts with antibodies to the polysaccharide glucuronoxylomannan, the most abundant component of the polysaccharide capsule required for C. neoformans virulence. We explored the role of capsule polysaccharide in spore development by assessing spore formation in a series of acapsular strains and determined that capsule biosynthesis genes are required for proper sexual development and normal spore formation. Our findings suggest that C. neoformans spores may have an adapted cell surface that facilitates persistence in harsh environments and ultimately allows them to infect mammalian hosts.
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Bagyan, Irina, and Peter Setlow. "Localization of the Cortex Lytic Enzyme CwlJ in Spores of Bacillus subtilis." Journal of Bacteriology 184, no. 4 (February 15, 2002): 1219–24. http://dx.doi.org/10.1128/jb.184.4.1219-1224.2002.
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ABSTRACT The enzyme CwlJ is involved in the depolymerization of cortex peptidoglycan during germination of spores of Bacillus subtilis. CwlJ with a C-terminal His tag was functional and was extracted from spores by procedures that remove spore coat proteins. However, this CwlJ was not extracted from disrupted spores by dilute buffer, high salt concentrations, Triton X-100, Ca2+-dipicolinic acid, dithiothreitol, or peptidoglycan digestion, disappeared during spore germination, and was not present in cotE spores in which the spore coat is aberrant. These findings indicate the following: (i) the reason decoated and cotE spores germinate poorly with dipicolinic acid is the absence of CwlJ from these spores; and (ii) CwlJ is located in the spore coat, presumably tightly associated with one or more other coat proteins.
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Montes-Bravo, Nicolás, Alba Romero-Rodríguez, José García-Yunge, César Medina, Marjorie Pizarro-Guajardo, and Daniel Paredes-Sabja. "Role of the Spore Coat Proteins CotA and CotB, and the Spore Surface Protein CDIF630_02480, on the Surface Distribution of Exosporium Proteins in Clostridioides difficile 630 Spores." Microorganisms 10, no. 10 (September 27, 2022): 1918. http://dx.doi.org/10.3390/microorganisms10101918.
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Clostridioides difficile is Gram-positive spore-former bacterium and the leading cause of nosocomial antibiotic-associated diarrhea. During disease, C. difficile forms metabolically dormant spores that persist in the host and contribute to recurrence of the disease. The outermost surface of C. difficile spores, termed the exosporium, plays an essential role in interactions with host surfaces and the immune system. The main exosporium proteins identified to date include three orthologues of the BclA family of collagen-like proteins, and three cysteine-rich proteins. However, how the underlying spore coat influences exosporium assembly remains unclear. In this work, we explore the contribution of spore coat proteins cotA and cotB, and the spore surface protein, CDIF630_02480, to the exosporium ultrastructure, formation of the polar appendage and the surface accessibility of exosporium proteins. Transmission electron micrographs of spores of insertional inactivation mutants demonstrate that while cotB contributes to the formation of thick-exosporium spores, cotA and CDIF630_02480 contribute to maintain proper thickness of the spore coat and exosporium layers, respectively. The effect of the absence of cotA, cotB and CDIF630_02480 on the surface accessibility of the exosporium proteins CdeA, CdeC, CdeM, BclA2 and BclA3 to antibodies was affected by the presence of the spore appendage, suggesting that different mechanisms of assembly of the exosporium layer might be implicated in each spore phenotype. Collectively, this work contributes to our understanding of the associations between spore coat and exosporium proteins, and how these associations affect the assembly of the spore outer layers. These results have implications for the development of anti-infecting agents targeting C. difficile spores.
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Laaberki, Maria-Halima, and Jonathan Dworkin. "Role of Spore Coat Proteins in the Resistance of Bacillus subtilis Spores to Caenorhabditis elegans Predation." Journal of Bacteriology 190, no. 18 (June 27, 2008): 6197–203. http://dx.doi.org/10.1128/jb.00623-08.
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ABSTRACT Bacterial spores are resistant to a wide range of chemical and physical insults that are normally lethal for the vegetative form of the bacterium. While the integrity of the protein coat of the spore is crucial for spore survival in vitro, far less is known about how the coat provides protection in vivo against predation by ecologically relevant hosts. In particular, assays had characterized the in vitro resistance of spores to peptidoglycan-hydrolyzing enzymes like lysozyme that are also important effectors of innate immunity in a wide variety of hosts. Here, we use the bacteriovorous nematode Caenorhabditis elegans, a likely predator of Bacillus spores in the wild, to characterize the role of the spore coat in an ecologically relevant spore-host interaction. We found that ingested wild-type Bacillus subtilis spores were resistant to worm digestion, whereas vegetative forms of the bacterium were efficiently digested by the nematode. Using B. subtilis strains carrying mutations in spore coat genes, we observed a correlation between the degree of alteration of the spore coat assembly and the susceptibility to the worm degradation. Surprisingly, we found that the spores that were resistant to lysozyme in vitro can be sensitive to C. elegans digestion depending on the extent of the spore coat structure modifications.
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Keller, Harold W., and Jean D. Schoknecht. "Spore-to-Spore Cultivation of a New Wrinkled-Reticulate-Spored Badhamia." Mycologia 81, no. 5 (September 1989): 783. http://dx.doi.org/10.2307/3759883.
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Keller, Harold W., and Jean D. Schoknecht. "Spore-to-Spore Cultivation of A New Wrinkled-Reticulate-Spored Badhamia." Mycologia 81, no. 5 (September 1989): 783–89. http://dx.doi.org/10.1080/00275514.1989.12025820.
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CAI, SHUNFENG, XINGMENG LU, HAIHONG QIU, MINGQIAN LI, and ZHENZHEN FENG. "Identification of a Nosema bombycis (Microsporidia) spore wall protein corresponding to spore phagocytosis." Parasitology 138, no. 9 (July 15, 2011): 1102–9. http://dx.doi.org/10.1017/s0031182011000801.
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SUMMARYLife-cycle stages of the microsporidia Nosema bombycis, the pathogen causing silkworm pebrine, were separated and purified by an improved method of Percoll-gradient centrifugation. Soluble protein fractions of late sporoblasts (spore precursor cells) and mature spores were analysed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Protein spots were recovered from gels and analysed by mass spectrometry. The most abundant differential protein spot was identified by database search to be a hypothetical spore wall protein. Using immunoelectron microscopy, we demonstrated that HSWP5 is localized to the exospore of mature spores and renamed it as spore wall protein 5 (NbSWP5). Further spore phagocytosis assays indicated that NbSWP5 can protect spores from phagocytic uptake by cultured insect cells. This spore wall protein may function both for structural integrity and in modulating host cell invasion.
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West, C. M., and G. W. Erdos. "Incorporation of protein into spore coats is not cell autonomous in Dictyostelium." Journal of Cell Biology 116, no. 5 (March 1, 1992): 1291–300. http://dx.doi.org/10.1083/jcb.116.5.1291.
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At maturity, the spores of Dictyostelium are suspended in a viscous fluid droplet, with each spore being surrounded by its own spore coat. Certain glycoproteins characteristic of the spore coat are also dissolved in this fluid matrix after the spore coat is formed. To determine whether any proteins of the coat reside in this fluid phase earlier during the process of spore coat assembly, pairs of strains which differed in a spore coat protein carbohydrate marker were mixed and allowed to form spore coats in each other's presence. We reasoned that proteins belonging to an early, soluble, extracellular pool would be incorporated into the spore coats of both strains. To detect trans-incorporation, spores were labeled with a fluorescent antibody against the carbohydrate marker and each spore's fluorescence was analyzed by flow cytometry. Several proteins of both the outer and inner protein layers of the coat appeared to be faithfully and reciprocally trans-incorporated and hence judged to belong to a soluble, assembly-phase pool. Western blot analysis of sorted spores, and EM localization, confirmed this conclusion. In contrast, one outer-layer protein was not trans-incorporated, and was concluded to be insoluble at the time of secretion. Three classes of spore coat proteins can be described: (a) Insoluble from the time of secretion; (b) present in the early, soluble pool but not the late pool after spore coat formation; and (c) present in the soluble pool throughout spore coat assembly. These classes may, respectively: (a) Nucleate spore coat assembly; (b) comprise a scaffold defining the dimensions of the nascent spore coat; and (c) complete the assembly process by intercalation into the scaffold.
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Ghosh, Sonali, and Peter Setlow. "Isolation and Characterization of Superdormant Spores of Bacillus Species." Journal of Bacteriology 191, no. 6 (January 9, 2009): 1787–97. http://dx.doi.org/10.1128/jb.01668-08.
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ABSTRACT Superdormant spores of Bacillus subtilis and Bacillus megaterium were isolated in 4 to 12% yields following germination with high nutrient levels that activated one or two germinant receptors. These superdormant spores did not germinate with the initial nutrients or those that stimulated other germinant receptors, and the superdormant spores' defect was not genetic. The superdormant spores did, however, germinate with Ca2+-dipicolinic acid or dodecylamine. Although these superdormant spores did not germinate with high levels of nutrients that activated one or two nutrient germinant receptors, they germinated with nutrient mixtures that activated more receptors, and using high levels of nutrient mixtures activating more germinant receptors decreased superdormant spore yields. The use of moderate nutrient levels to isolate superdormant spores increased their yields; the resultant spores germinated poorly with the initial moderate nutrient concentrations, but they germinated well with high nutrient concentrations. These findings suggest that the levels of superdormant spores in populations depend on the germination conditions used, with fewer superdormant spores isolated when better germination conditions are used. These findings further suggest that superdormant spores require an increased signal for triggering spore germination compared to most spores in populations. One factor determining whether a spore is superdormant is its level of germinant receptors, since spore populations with higher levels of germinant receptors yielded lower levels of superdormant spores. A second important factor may be heat activation of spore populations, since yields of superdormant spores from non-heat-activated spore populations were higher than those from optimally activated spores.
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Setlow, Barbara, Swaroopa Atluri, Ryan Kitchel, Kasia Koziol-Dube, and Peter Setlow. "Role of Dipicolinic Acid in Resistance and Stability of Spores of Bacillus subtilis with or without DNA-Protective α/β-Type Small Acid-Soluble Proteins." Journal of Bacteriology 188, no. 11 (June 1, 2006): 3740–47. http://dx.doi.org/10.1128/jb.00212-06.
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ABSTRACT Dipicolinic acid (DPA) comprises ∼10% of the dry weight of spores of Bacillus species. Although DPA has long been implicated in spore resistance to wet heat and spore stability, definitive evidence on the role of this abundant molecule in spore properties has generally been lacking. Bacillus subtilis strain FB122 (sleB spoVF) produced very stable spores that lacked DPA, and sporulation of this strain with DPA yielded spores with nearly normal DPA levels. DPA-replete and DPA-less FB122 spores had similar levels of the DNA protective α/β-type small acid-soluble spore proteins (SASP), but the DPA-less spores lacked SASP-γ. The DPA-less FB122 spores exhibited similar UV resistance to the DPA-replete spores but had lower resistance to wet heat, dry heat, hydrogen peroxide, and desiccation. Neither wet heat nor hydrogen peroxide killed the DPA-less spores by DNA damage, but desiccation did. The inability to synthesize both DPA and most α/β-type SASP in strain PS3664 (sspA sspB sleB spoVF) resulted in spores that lost viability during sporulation, at least in part due to DNA damage. DPA-less PS3664 spores were more sensitive to wet heat than either DPA-less FB122 spores or DPA-replete PS3664 spores, and the latter also retained viability during sporulation. These and previous results indicate that, in addition to α/β-type SASP, DPA also is extremely important in spore resistance and stability and, further, that DPA has some specific role(s) in protecting spore DNA from damage. Specific roles for DPA in protecting spore DNA against damage may well have been a major driving force for the spore's accumulation of the high levels of this small molecule.
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Jeffs, Lloyd B., Ilungo J. Xavier, Russell E. Matai, and George G. Khachatourians. "Relationships between fungal spore morphologies and surface properties for entomopathogenic members of the general Beauveria, Metarhizium, Paecilomyces,Tolypocladium, and Verticillium." Canadian Journal of Microbiology 45, no. 11 (November 1, 1999): 936–48. http://dx.doi.org/10.1139/w99-097.
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The surface properties of aerial conidia (AC) from 24 strains of entomopathogenic fungi were studied and compared using the salt-mediated aggregation and sedimentation (SAS) assay, electron microscopy, FITC-labelled lectins, and spore dimensions. Spores with rugose surfaces were hydrophobic, whereas hydrophilic spores had smooth surfaces. Correlation analysis found no link between spore dimensions and either hydrophobicity or surface carbohydrates. However, there was a strong positive correlation between spore hydrophobicity and surface carbohydrates. The three spore types of Beauveria bassiana were all shown to possess discrete surface hydrophobicities, which were also strongly linked to surface carbohydrate profiles. Various chemical treatments had pronounced effects on spore surface properties, with sodium dodecyl sulfate (SDS) and formic acid (FA) reducing both lectin binding and surface hydrophobicity. When FA-protein extracts were separated and analysed using SDS-PAGE, only the hydrophobic spores had low molecular weight hydrophobin-like peptides that were unglycosylated and contained disulfide bonds. The strains with hydrophilic AC had much lower levels of FA-extractable protein per spore dry weight compared to their more hydrophobic counterparts. Moreover, extracts of the more hydrophobic spores tended to have greater protein:carbohydrate ratios.Key words: fungi, spores, hydrophobicity, lectins, morphology, microbial insecticides, protein.
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Sztejnberg, Abraham, Sergio Galper, and Norberto Lisker. "Conditions for pycnidial production and spore formation by Ampelomyces quisqualis." Canadian Journal of Microbiology 36, no. 3 (March 1, 1990): 193–98. http://dx.doi.org/10.1139/m90-033.
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On Czapek agar medium, the optimum temperature for spore germination and pycnidia formation by Ampelomyces quisqualis was 20 and 25 °C, respectively. Inoculation of Czapek agar medium with a spore concentration of 106 or 107/mL significantly increased pycnidia formation as compared with medium inoculated with 104 or 105 spores/mL. In shaken cultures, spore formation in potato dextrose broth (PDB) was higher than in the broth of bran extract and glycerol, aspargine, Czapek, Joham, and synthetic Mucor media. On PDB, pycnidia were formed in hard black aggregates. Spore production in fermentors was similar to that in shaken cultures. The omission of glucose from PDB caused a great increase in the number of spores formed. Also, PDB prepared with the broth of 100 g (instead of the usual 200 g) peeled potatoes/L was effective in spore formation and maintained spore infectivity as high as in controls. It seems that the broth of boiled potatoes is a simple, efficient, and nonexpensive medium for mass production of infective A. quisqualis spores. Key words: Ampelomyces quisqualis, pycnidial production, spore formation, biological control, powdery mildew.
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Miller, Steven L. "A systematic evaluation of basidiospore symmetry and tegumentation in hypogeous and gasteroid Russulales." Canadian Journal of Botany 66, no. 12 (December 1, 1988): 2561–73. http://dx.doi.org/10.1139/b88-347.
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Spore wall architecture and ontogeny of ornamentation in several genera and species of hypogeous and gasteroid Russulales are similar to those described previously for agaricoid Lactarius lignyotellus. Spore walls are composed of four layers, each differing in thickness and electron density. Layer 2 is electron transparent and corresponds to a dark blue, amyloid layer when mounted in Melzer's iodine reagent and viewed with the light microscope. Establishment of spore symmetry may be regulated by the hilar appendix body, which is a poorly differentiated cytoplasmic region in the hilar appendix of asymmetric spores of Macowanites luteolus, Elasmomyces russuloides, and Zelleromyces versicaulus but which is absent in symmetric spores of Z. sculptisporus, Martellia subochracea, and Gymnomyces yubaensis. A continuum in spore morphology from truly symmetric to asymmetric is evident in spores from individual sporocarps of many species of the Russulales. The variation in spore symmetry and spore surface ornamentation has clouded taxonomic concepts in the Russulales. Systematically, development of orthotropic and heterotropic spores has been regarded as two distinct end points of evolution, when they are likely terms describing degrees of the same phenomenon. The current circumscription of families and genera in the Russulales based on spore symmetry, therefore, appears to be artificial.
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Andrade, David, Zaitao Pan, William Dannevik, and Jeremy Zidek. "Modeling Soybean Rust Spore Escape from Infected Canopies: Model Description and Preliminary Results." Journal of Applied Meteorology and Climatology 48, no. 4 (April 1, 2009): 789–803. http://dx.doi.org/10.1175/2008jamc1917.1.
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Abstract Asian soybean rust, caused by Phakopsora pachyrhizi, an airborne fungal pathogen, is an annual threat to U.S. soybean production. The disease is spread during the growing season by fungal spores that are transported from warm southern locations where they overwinter. Current models of long distance spore transport treat spore sources as constant emitters. However, evidence suggests that the spore escape rate depends on 1) the interaction between spores and turbulence within and above an infected canopy and 2) the filtering capacity of the canopy to trap upward-traveling spores. Accordingly, a theoretically motivated yet computationally simple forecast model for escape rate is proposed using a simple turbulence closure method and a parameterization of the canopy porosity. Preliminary escape-rate forecasts were made using the friction velocity, an estimate of initial spore concentrations inside an infected canopy, and the canopy’s leaf area distribution. Sensitivity tests were conducted to determine which biological and meteorological variables and parameters most impact modeled spore escape rates. The spore escape model was integrated with a large-scale spore transport model that was used to forecast spore deposition over U.S. soybean production regions. Preliminary results suggest that varying meteorological conditions significantly impact escape rates and the spread of the disease.
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BEARHAM, D., Z. SPIERS, S. RAIDAL, J. B. JONES, E. M. BURRESON, and P. K. NICHOLLS. "Spore ornamentation of Haplosporidium hinei n. sp. (Haplosporidia) in pearl oysters Pinctada maxima (Jameson, 1901)." Parasitology 135, no. 4 (February 4, 2008): 521–27. http://dx.doi.org/10.1017/s0031182008004149.
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SUMMARYAn infection of pearl oysters, Pinctada maxima, attributed to a Haplosporidium sp. by Hine and Thorne (1998) has been detected on 3 occasions and is considered to represent a serious concern to the pearling industry in Australia. The spore ornamentation of the parasite was determined by scanning electron microscopy and transmission electron microscopy. Spores of the parasite were pleomorphic, or elongated 3·5–4 μm×2·5–3·0 μm in size. Two filaments were wound around the spore and originated from 2 ‘knob-like’ posterior thickenings. Both filaments passed up one side of the spore together until just below the operculum whereupon each split and passed obliquely under the lip of the opercula lid. Each filament wrapped around the spore 4 times. The posterior thickenings seem to appear late in the development of the spore and were composed of spore wall material. A second set of branching tubular filaments composed of a different material was observed on the spore body although not on mature spores possessing a ‘knob-like’ posterior thickening. The ornamentation on the spores of the pearl oyster parasite was unique amongst described haplosporidian species where spore ornamentation is known. The parasite is named in this manuscript as Haplosporidium hinei n. sp.
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Úrbez-Torres, J. R., M. Battany, L. J. Bettiga, C. Gispert, G. McGourty, J. Roncoroni, R. J. Smith, P. Verdegaal, and W. D. Gubler. "Botryosphaeriaceae Species Spore-Trapping Studies in California Vineyards." Plant Disease 94, no. 6 (June 2010): 717–24. http://dx.doi.org/10.1094/pdis-94-6-0717.
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The seasonal abundance of Botryosphaeriaceae spp. spores was studied in California vineyards by using glass microscope slides covered with petroleum jelly placed on grapevine cordons and Burkard volumetric spore traps at seven and two different locations, respectively. Correlation analysis was used to determine which meteorological variables (precipitation, relative humidity, temperature, and wind speed) influenced Botryosphaeriaceae spp. spore release. Among all variables, regression analysis resulted in a strong relationship between spore release and precipitation. Additionally, a positive relationship between irrigation and spore release was also observed in the Riverside County vineyard. During the study period, spore discharge of Botryosphaeriaceae spp. occurred from the first fall rain through the last spring rains, coinciding with September to April. However, based on the results obtained from the spore traps, most spores (over 60%) were trapped following rain events during the winter months of December, January, and February, which coincides with the grapevine pruning season. Botryosphaeriaceae spp. spore release was much lower in fall and early spring (22%) and very few or no spores were trapped in late spring and summer (3%). This work suggests that a delay of pruning time in California may be warranted to reduce grapevine infection because the current timing coincides with the greatest period of spore discharge.
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Meliza, Rezika, Tatik Chikmawati, and Sulistijorini Sulistijorini. "MORFOLOGI SPORA DAN PERKEMBANGAN GAMETOFIT Davallia denticulata dan Davallia trichomanoides." Jurnal Bioteknologi & Biosains Indonesia (JBBI) 6, no. 1 (June 17, 2019): 1. http://dx.doi.org/10.29122/jbbi.v6i1.2607.
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Spore Morphology and Gametophyte Development of Davallia denticulata and Davallia trichomanoidesABSTRACTDavallia denticulata and D. trichomanoides are two attractive and decorative fern species for ornamental. Spore morphology has an important role in fern taxonomy, while media composition has important role in the growth and development of their gametophytes. Such information on the two fern species was lacking. Therefore, this study aimed to reveal the information of the spore morphology and gametophyte developmental stages of D. denticulata and D. trichomanoides on three different media. The spores were collected from Bogor, West Java. The spores were sown in three sterile media. Spore morphology and gametophyte development were observed under a stereoscopic microscope. Both gametophyte species reached their mature stage at 25 weeks after planting on the different media compositions. D. denticulata showed the best gametophyte development, and formed mature gametophytes on the media of vermiculite, sphagnum moss, and perlite, while D. trichomanoides grew best into maturity stage on the media containing vermiculite, and sphagnum moss. Thus, the presence of sphagnum moss in the media is an important material for the growth and development of Davallia gametophyte.Keywords: Davallia, development, gametophyte, growth, media ABSTRAKDavallia denticulata dan D. trichomanoides merupakan dua spesies tumbuhan paku yang menarik dan indah untuk tanaman hias. Morfologi spora memiliki arti penting dalam taksonomi tumbuhan paku, sedangkan komposisi media berperan penting untuk pertumbuhan dan perkembangan gametofitnya. Informasi seputar hal ini terkait dua spesies tumbuhan paku tersebut belumlah ada. Penelitian ini bertujuan untuk mengungkap informasi mengenai ciri morfologi spora dan tahapan perkembangan gametofit D. denticulata dan D. trichomanoides pada tiga komposisi media berbeda. Pengambilan spora dilakukan di Bogor, Jawa Barat. Spora ditumbuhkan pada tiga media steril. Morfologi spora dan perkembangan gametofit diamati menggunakan mikroskop stereo. Kedua spesies memiliki waktu perkembangan terbaik untuk mencapai tahap gametofit dewasa yaitu 25 minggu pada komposisi media yang berbeda. D. denticulata berkembang dengan baik, dan membentuk gametofit dewasa pada media vermiculite, lumut sphagnum, dan perlite. D. trichomanoides berkembang hingga tahap gametofit dewasa dengan baik pada media vermiculite, dan lumut sphagnum. Dengan demikian keberadaan lumut sphagnum pada media sangat penting untuk pertumbuhan dan perkembangan gametofit Davallia.Kata Kunci: Davallia, gametofit, media, perkembangan, pertumbuhan
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Yi, Xuan, and Peter Setlow. "Studies of the Commitment Step in the Germination of Spores of Bacillus Species." Journal of Bacteriology 192, no. 13 (April 30, 2010): 3424–33. http://dx.doi.org/10.1128/jb.00326-10.
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ABSTRACT Spores of Bacillus species are said to be committed when they continue through nutrient germination even when germinants are removed or their binding to spores' nutrient germinant receptors (GRs) is both reversed and inhibited. Measurement of commitment and the subsequent release of dipicolinic acid (DPA) during nutrient germination of spores of Bacillus cereus and Bacillus subtilis showed that heat activation, increased nutrient germinant concentrations, and higher average levels of GRs/spore significantly decreased the times needed for commitment, as well as lag times between commitment and DPA release. These lag times were also decreased dramatically by the action of one of the spores' two redundant cortex lytic enzymes (CLEs), CwlJ, but not by the other CLE, SleB, and CwlJ action did not affect the timing of commitment. The timing of commitment and the lag time between commitment and DPA release were also dependent on the specific GR activated to cause spore germination. For spore populations, the lag times between commitment and DPA release were increased significantly in spores that germinated late compared to those that germinated early, and individual spores that germinated late may have had lower appropriate GR levels/spore than spores that germinated early. These findings together provide new insight into the commitment step in spore germination and suggest several factors that may contribute to the large heterogeneity among the timings of various events in the germination of individual spores in spore populations.
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Lawley, Trevor D., Nicholas J. Croucher, Lu Yu, Simon Clare, Mohammed Sebaihia, David Goulding, Derek J. Pickard, Julian Parkhill, Jyoti Choudhary, and Gordon Dougan. "Proteomic and Genomic Characterization of Highly Infectious Clostridium difficile 630 Spores." Journal of Bacteriology 191, no. 17 (June 19, 2009): 5377–86. http://dx.doi.org/10.1128/jb.00597-09.
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ABSTRACT Clostridium difficile, a major cause of antibiotic-associated diarrhea, produces highly resistant spores that contaminate hospital environments and facilitate efficient disease transmission. We purified C. difficile spores using a novel method and show that they exhibit significant resistance to harsh physical or chemical treatments and are also highly infectious, with <7 environmental spores per cm2 reproducibly establishing a persistent infection in exposed mice. Mass spectrometric analysis identified ∼336 spore-associated polypeptides, with a significant proportion linked to translation, sporulation/germination, and protein stabilization/degradation. In addition, proteins from several distinct metabolic pathways associated with energy production were identified. Comparison of the C. difficile spore proteome to those of other clostridial species defined 88 proteins as the clostridial spore “core” and 29 proteins as C. difficile spore specific, including proteins that could contribute to spore-host interactions. Thus, our results provide the first molecular definition of C. difficile spores, opening up new opportunities for the development of diagnostic and therapeutic approaches.
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Persidis, A., J. G. Lay, T. Manousis, A. H. Bishop, and D. J. Ellar. "Characterisation of potential adhesins of the bacterium Pasteuria penetrans, and of putative receptors on the cuticle of Meloidogyne incognita, a nematode host." Journal of Cell Science 100, no. 3 (November 1, 1991): 613–22. http://dx.doi.org/10.1242/jcs.100.3.613.
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Pasteuria penetrans spores were fragmented by glass bead vortexing, producing exosporial membranes and spore fragments, which consisted of fibre bundles. Both exosporia and spore fragments are capable of host-specific attachment to the cuticle of Meloidogyne incognita, a root-knot nematode host. Putative M. incognita receptors appear to be soluble in beta-mercaptoethanol (BME) but not SDS, and are also sensitive to tryptic digestion and deglycosylation by endoglycosidase F. Polyclonal antibodies against intact spores and spore fragments of antispore antibodies produced 100% inhibition. The antibodies, however, did not show preferential staining of particular spore structures in thin section immunolabelling studies. Exposure of Pasteuria penetrans spores to HCl or urea-SDS-dithiothreitol renders them incapable of attachment to their host juveniles and extensively disrupts fibres that surround the spore core. Protein extracts from spore fragments or from exosporial membranes are identical, and urea-BME extracts from either structure, but not SDS extracts, can inhibit the attachment of spores to juveniles by 60–80%. An inhibitory BME extract from spore fragments was analysed by anion-exchange chromatography and adsorption onto host cuticle followed by immunoblotting. It appeared to contain six potential spore adhesins of approximate Mr 24–29, 38–47, 59, 89, 126, and 190 (x10(3)). Lectin affinity blotting with wheat germ agglutinin and concanavalin A showed that all of these proteins bear terminal N-acetylglucosamine residues and the 38–47 kDa band also bears terminal Glc/Man residues.(ABSTRACT TRUNCATED AT 250 WORDS)
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Moeller, Ralf, Peter Setlow, Gerda Horneck, Thomas Berger, Günther Reitz, Petra Rettberg, Aidan J. Doherty, Ryuichi Okayasu, and Wayne L. Nicholson. "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." Journal of Bacteriology 190, no. 3 (November 30, 2007): 1134–40. http://dx.doi.org/10.1128/jb.01644-07.
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ABSTRACT The role of DNA repair by nonhomologous end joining (NHEJ), homologous recombination, spore photoproduct lyase, and DNA polymerase I and genome protection via α/β-type small, acid-soluble spore proteins (SASP) in Bacillus subtilis spore resistance to accelerated heavy ions (high-energy charged [HZE] particles) and X rays has been studied. Spores deficient in NHEJ and α/β-type SASP were significantly more sensitive to HZE particle bombardment and X-ray irradiation than were the recA, polA, and splB mutant and wild-type spores, indicating that NHEJ provides an efficient DNA double-strand break repair pathway during spore germination and that the loss of the α/β-type SASP leads to a significant radiosensitivity to ionizing radiation, suggesting the essential function of these spore proteins as protectants of spore DNA against ionizing radiation.
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Schmale, David G., Denis A. Shah, and Gary C. Bergstrom. "Spatial Patterns of Viable Spore Deposition of Gibberella zeae in Wheat Fields." Phytopathology® 95, no. 5 (May 2005): 472–79. http://dx.doi.org/10.1094/phyto-95-0472.
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An increased understanding of the epidemiology of Gibberella zeae will contribute to a rational and informed approach to the management of Fusarium head blight (FHB). An integral phase of the FHB cycle is the deposition of airborne spores, yet there is no information available on the spatial pattern of spore deposition of G. zeae above wheat canopies. We examined spatial patterns of viable spore deposition of G. zeae over rotational (lacking cereal debris) wheat fields in New York in 2002 and 2004. Viable, airborne spores (ascospores and macroconidia) of G. zeae were collected above wheat spikes on petri plates containing a selective medium and the resulting colonies were counted. Spores of G. zeae were collected over a total of 68 field environments (three wheat fields during 54 day and night sample periods over 2 years) from spike emergence to kernel milk stages of local wheat. Spatial patterns of spore deposition were visualized by contour plots of spore counts over entire fields. The spatial pattern of spore deposition was unique for each field environment during each day and night sample period. Spore deposition patterns during individual sample periods were classified by spatial analysis by distance indices (SADIE) statistics and Mantel tests. Both analyses indicated that the majority (93%) of the spore deposition events were random, with the remainder being aggregated. All of the aggregated patterns were observed during the night. Observed patterns of spore deposition were independent of the mean number of viable spores deposited during individual sample periods. The spatial pattern for cumulative spore deposition during anthesis in both years became aggregated over time. Contour maps of daily and cumulative spore deposition could be compared with contour maps of FHB incidence to gain insights into inoculum thresholds and the timing of effective inoculum for infection.
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Huang, Shu-shi, De Chen, Patricia L. Pelczar, Venkata Ramana Vepachedu, Peter Setlow, and Yong-qing Li. "Levels of Ca2+-Dipicolinic Acid in Individual Bacillus Spores Determined Using Microfluidic Raman Tweezers." Journal of Bacteriology 189, no. 13 (April 27, 2007): 4681–87. http://dx.doi.org/10.1128/jb.00282-07.
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ABSTRACT Pyridine-2,6-dicarboxylic acid (dipicolinic acid [DPA]) in a 1:1 chelate with calcium ion (Ca-DPA) comprises 5 to 15% of the dry weight of spores of Bacillus species. Ca-DPA is important in spore resistance to many environmental stresses and in spore stability, and Ca-DPA levels in spore populations can vary with spore species/strains, as well as with sporulation conditions. We have measured levels of Ca-DPA in large numbers of individual spores in populations of a variety of Bacillus species and strains by using microfluidic Raman tweezers, in which a single spore is trapped in a focused laser beam and its Ca-DPA is quantitated from the intensity of the Ca-DPA-specific band at 1,017 cm−1 in Raman spectroscopy. Conclusions from these measurements include the following: (i) Ca-DPA concentrations in the spore core are >800 mM, well above Ca-DPA solubility; (ii) SpoVA proteins may be involved in Ca-DPA uptake in sporulation; and (iii) Ca-DPA levels differ significantly among individual spores in a population, but much of this variation could be due to variations in the sizes of individual spores.
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Chang, Kan-Fa, P. V. Blenis, and Y. Hiratsuka. "Mechanism and pattern of spore release by Endocronartium harknessii." Canadian Journal of Botany 67, no. 1 (January 1, 1989): 104–11. http://dx.doi.org/10.1139/b89-015.
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Hourly measurements of spore release by Endocronartium harknessii (J. P. Moore) Y. Hiratsuka on Pinus contorta Doug. var. latifolia Engelm. were obtained during 2 years. Two spore traps were placed beside both of two sporulating galls and electronic data loggers were used to record environmental data. On rainless days, most spores were trapped between 0900 and 2200, when vapor pressure deficit, temperature, light intensity, and wind velocity were high. A similar pattern of spore release occurred under simulated daytime and nighttime conditions in a growth chamber. On rainy days, most spores were released, on average, over a longer time interval than on dry days. Within 9 h of being placed in a dew chamber, the previously intact peridia on a single gall had ruptured, presumably from pressure caused by spore production. Further evidence that spore production is stimulated by low vapor pressure deficit was obtained by moving 11 galls alternatively between humid and dry conditions. Thus, it is proposed that the diurnal periodicity of spore release on dry days results from the production of spores during the night and the subsequent passive release of those spores during the next day.
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Krishna, Vijay, Jue Zhao, Ben Koopman, and Brij Moudgil. "Purification procedure sensitizesBacillusendospores to free radicals from UVA radiation and photocatalysis." International Journal of Astrobiology 17, no. 4 (August 3, 2017): 329–35. http://dx.doi.org/10.1017/s1473550417000258.
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AbstractMany researchers are investigating the extreme resilience of bacterial endospores against chemical and physical inactivating agents. The presence of vegetative cells in spore suspensions can result in overly optimistic assessment of inactivating agents; therefore, various spore purification methods have been applied to separate spores from vegetative cells prior to testing. The present study was undertaken to evaluate the effect of two widely used spore purification methodologies on spore integrity and susceptibility to ultraviolet-A (UVA) radiation and free radicals generated from photocatalysts.Bacillus subtilisandBacillus cereusspores were purified by procedures that involved heat shock alone or chemical washes, lysozyme treatment and heat shock (CLH). The purified spores were exposed to UVA radiation or free radicals generated by photocatalyst and susceptibility were evaluated in terms of survival ratio. The effect of purification procedure on the spore morphology was investigated with electron microscopy. The CLH purification process significantly damages spore coats and increases the susceptibility ofBacillusspores to UVA radiation and photocatalytic inactivation. It is therefore likely that the survival of CLH treated spores in extra-terrestrial environments would be less than that of the same spores purified by a less aggressive procedure.
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HAMPSON, M. CHISNALL, and ALEXANDER ROBERTSON. "Distribution of Fungal Spores and Fractal Diversity of Quadrats on Membrane Filters†." Journal of Food Protection 58, no. 9 (September 1, 1995): 1038–41. http://dx.doi.org/10.4315/0362-028x-58.9.1038.
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In standard practice, estimations of populations of fungal spores on gridded membrane filter discs are made from spore loads in arbitrarily selected groups or rows of grids (quadrats). We used the resting spores of Synchytrium endobioticum to examine actual/expected spore ratio. The ratios showed unacceptable divergences, and are characterized by an aggregated spore distribution. The fractal diversity index of the quadrats is inversely related the loga of the population numbers. The analysis gives values for the appropriate spore number per quadrat and the quadrat pattern to yield the best actual/expected ratio.
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Paredes-Sabja, Daniel, Peter Setlow, and Mahfuzur R. Sarker. "Role of GerKB in Germination and Outgrowth of Clostridium perfringens Spores." Applied and Environmental Microbiology 75, no. 11 (April 10, 2009): 3813–17. http://dx.doi.org/10.1128/aem.00048-09.
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ABSTRACT Previous work indicated that Clostridium perfringens gerKA gerKC spores germinate significantly, suggesting that gerKB also has a role in C. perfringens spore germination. We now find that (i) gerKB was expressed only during sporulation, likely in the forespore; (ii) gerKB spores germinated like wild-type spores with nonnutrient germinants and with high concentrations of nutrients but more slowly with low nutrient concentrations; and (iii) gerKB spores had lower colony-forming efficiency and slower outgrowth than wild-type spores. These results suggest that GerKB plays an auxiliary role in spore germination under some conditions and is required for normal spore viability and outgrowth.
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Hoa, Tran Thu, Le Hong Duc, Rachele Isticato, Loredana Baccigalupi, Ezio Ricca, Pham Hung Van, and Simon M. Cutting. "Fate and Dissemination of Bacillus subtilis Spores in a Murine Model." Applied and Environmental Microbiology 67, no. 9 (September 1, 2001): 3819–23. http://dx.doi.org/10.1128/aem.67.9.3819-3823.2001.
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ABSTRACT Bacterial spores are being consumed as probiotics, although little is known about their efficacy or mode of action. As a first step in characterizing spore probiotics, we have studied the persistence and dissemination of Bacillus subtilis spores given orally to mice. Our results have shown that spores do not appear to disseminate across the mucosal surfaces. However, we found that the number of spores excreted in the feces of mice was, in some experiments, larger than the original inoculum. This was an intriguing result and might be explained by germination of a proportion of the spore inoculum in the intestinal tract, followed by limited rounds of cell growth and then sporulation again. This result raises the interesting question of whether it is the spore or the germinated spore that contributes to the probiotic effect of bacterial spores.
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Dowd, Melissa M., Benjamin Orsburn, and David L. Popham. "Cortex Peptidoglycan Lytic Activity in Germinating Bacillus anthracis Spores." Journal of Bacteriology 190, no. 13 (May 2, 2008): 4541–48. http://dx.doi.org/10.1128/jb.00249-08.
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ABSTRACT 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 found in other species. During germination, B. anthracis released peptidoglycan fragments into the surrounding medium more quickly than some other species. A major lytic enzymatic activity was a glucosaminidase, probably YaaH, that cleaved between N-acetylglucosamine and muramic-δ-lactam. An epimerase activity previously proposed to function on spore peptidoglycan was not detected, and it is proposed that glucosaminidase products were previously misidentified as epimerase products. Spore cortex lytic enzymes and their regulators are attractive targets for development of germination inhibitors to kill spores and for development of activators to cause loss of resistance properties for decontamination of spore release sites.
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Pleshinger, J., and E. Weidner. "The microsporidian spore invasion tube. IV. Discharge activation begins with pH-triggered Ca2+ influx." Journal of Cell Biology 100, no. 6 (June 1, 1985): 1834–38. http://dx.doi.org/10.1083/jcb.100.6.1834.
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The microsporidian spore extrusion apparatus activates with a calcium influx from Spraguea lophii spore wall/plasma membrane; this influx requires preconditioning with an extrasporular shift in medium pH to the alkaline in the presence of the polyanions mucin or polyglutamate. Undischarged S. lophii spores display calcium bound to the wall/plasma membrane with a characteristic calcium-chlorotetracycline fluorescence; this fluorescence declines significantly during spore discharge. S. lophii spores do not discharge when spore wall/plasma membrane calcium is removed with EGTA. Extrasporular mucin or polyglutamate and a pH shift to the alkaline appear to be necessary preconditions for the triggering of the influx of spore wall/plasma membrane-bound 45Ca2+. Ionophore A-23187 also effectively activates spore discharge without other extrasporular polyanions. Micromolar concentrations of the calcium antagonists lanthanum or verapamil prevent spore discharge, and micromolar concentrations of calmodulin inhibitors chlorpromazine and trifluroperazine prevent spore discharge. Calmodulin, visualized with a calmodulin antibody and a peroxidase conjugate, is localized particularly on the plasma membrane and the polaroplast membranes of the extrusion apparatus.
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Shi, Libing, Zijie Li, Hiroyuki Tachikawa, Xiao-Dong Gao, and Hideki Nakanishi. "Use of Yeast Spores for Microencapsulation of Enzymes." Applied and Environmental Microbiology 80, no. 15 (May 16, 2014): 4502–10. http://dx.doi.org/10.1128/aem.00153-14.
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ABSTRACTHere, we report a novel method to produce microencapsulated enzymes usingSaccharomyces cerevisiaespores. In sporulating cells, soluble secreted proteins are transported to the spore wall. Previous work has shown that the spore wall is capable of retaining soluble proteins because its outer layers work as a diffusion barrier. Accordingly, a red fluorescent protein (RFP) fusion of the α-galactosidase, Mel1, expressed in spores was observed in the spore wall even after spores were subjected to a high-salt wash in the presence of detergent. In vegetative cells, however, the cell wall cannot retain the RFP fusion. Although the spore wall prevents diffusion of proteins, it is likely that smaller molecules, such as sugars, pass through it. In fact, spores can contain much higher α-galactosidase activity to digest melibiose than vegetative cells. When present in the spore wall, the enzyme acquires resistance to environmental stresses including enzymatic digestion and high temperatures. The outer layers of the spore wall are required to retain enzymes but also decrease accessibility of the substrates. However, mutants with mild spore wall defects can retain and stabilize the enzyme while still permitting access to the substrate. In addition to Mel1, we also show that spores can retain the invertase. Interestingly the encapsulated invertase has significantly lower activity toward raffinose than toward sucrose. This suggests that substrate selectivity could be altered by the encapsulation.
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Liu, Yong-Biao, Bruce E. Tabashnik, William J. Moar, and Robert A. Smith. "Synergism between Bacillus thuringiensis Spores and Toxins against Resistant and Susceptible Diamondback Moths (Plutella xylostella)." Applied and Environmental Microbiology 64, no. 4 (April 1, 1998): 1385–89. http://dx.doi.org/10.1128/aem.64.4.1385-1389.1998.
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ABSTRACT We studied the effects of combinations of Bacillus thuringiensis spores and toxins on the mortality of diamondback moth (Plutella xylostella) larvae in leaf residue bioassays. Spores of B. thuringiensis subsp.kurstaki increased the toxicity of crystals of B. thuringiensis subsp. kurstaki to both resistant and susceptible larvae. For B. thuringiensis subsp.kurstaki, resistance ratios were 1,200 for a spore-crystal mixture and 56,000 for crystals without spores. Treatment of a spore-crystal formulation of B. thuringiensissubsp. kurstaki with the antibiotic streptomycin to inhibit spore germination reduced toxicity to resistant larvae but not to susceptible larvae. In contrast, analogous experiments withB. thuringiensis subsp.aizawai revealed no significant effects of adding spores to crystals or of treating a spore-crystal formulation with streptomycin. Synergism occurred between Cry2A and B. thuringiensis subsp. kurstaki spores against susceptible larvae and between Cry1C and B. thuringiensis subsp. aizawai spores against resistant and susceptible larvae. The results show thatB. thuringiensis toxins combined with spores can be toxic even though the toxins and spores have little or no independent toxicity. Results reported here and previously suggest that, for diamondback moth larvae, the extent of synergism between spores and toxins of B. thuringiensis depends on the strain of insect, the type of spore, the set of toxins, the presence of other materials such as formulation ingredients, and the concentrations of spores and toxins.