Zeitschriftenartikel zum Thema „Sporulation conditions“
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1
Ferreira, Julio C., Anita D. Panek und Pedro S. de Araujo. „Inactivation of maltose permease and maltase in sporulatingSaccharomyces cerevisiae“. Canadian Journal of Microbiology 46, Nr. 4 (01.04.2000): 383–86. http://dx.doi.org/10.1139/w99-136.
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Maltose transport and maltase activities were inactivated during sporulation of a MAL constitutive yeast strain harboring different MAL loci. Both activities were reduced to almost zero after 5 h of incubation in sporulation medium. The inactivation of maltase and maltose permease seems to be related to optimal sporulation conditions such as a suitable supply of oxygen and cell concentration in the sporulating cultures, and occurs in the fully derepressed conditions of incubation in the sporulation acetate medium. The inactivation of maltase and maltose permease under sporulation conditions in MAL constitutive strains suggests an alternative mechanism for the regulation of the MAL gene expression during the sporulation process.Key words: maltase activity, maltose permease activity, sporulation, Saccharomyces cerevisiae.
2
Ozsarac, N., M. J. Straffon, H. E. Dalton und I. W. Dawes. „Regulation of gene expression during meiosis in Saccharomyces cerevisiae: SPR3 is controlled by both ABFI and a new sporulation control element.“ Molecular and Cellular Biology 17, Nr. 3 (März 1997): 1152–59. http://dx.doi.org/10.1128/mcb.17.3.1152.
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The SPR3 gene encodes a sporulation-specific homolog of the yeast Cdc3/10/11/12 family of bud neck filament proteins. It is expressed specifically during meiosis and sporulation in Saccharomyces cerevisiae. Analysis of the sporulation-specific regulation of SPR3 has shown that it is strongly activated under sporulating conditions but shows low levels of expression under nonsporulating conditions. A palindromic sequence located near the TATA box is essential to the developmental regulation of this gene and is the only element directly activating SPR3 at the right time during sporulation. Within the palindrome is a 9-bp sequence, gNCRCAAA(A/T) (midsporulation element [MSE]), found in the known control regions of three other sporulation genes. A previously identified ABFI element is also needed for activation. The MSE has been shown to activate a heterologous promoter (CYC1) in a sporulation-specific manner. Related sequences, including an association of MSE and ABFI elements, have been found upstream of other genes activated during the middle stage of S. cerevisiae sporulation. One group of these may be involved in spore coat formation or maturation.
3
Eswaramoorthy, Prahathees, Jeffrey Dinh, Daniel Duan, Oleg A. Igoshin und Masaya Fujita. „Single-cell measurement of the levels and distributions of the phosphorelay components in a population of sporulating Bacillus subtilis cells“. Microbiology 156, Nr. 8 (01.08.2010): 2294–304. http://dx.doi.org/10.1099/mic.0.038497-0.
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Upon nutrient starvation, the Gram-positive bacterium Bacillus subtilis switches from growth to sporulation by activating a multicomponent phosphorelay consisting of a major sensor histidine kinase (KinA), two phosphotransferases (Spo0F and Spo0B) and a response regulator (Spo0A). Although the primary sporulation signal(s) produced under starvation conditions is not known, it is believed that the reception of a signal(s) on the sensor kinase results in the activation of autophosphorylation of the enzyme. The phosphorylated kinase transfers the phosphate group to Spo0A via the phosphorelay and thus triggers sporulation. With a combination of quantitative immunoblot analysis, microscopy imaging and computational analysis, here we found that each of the phosphorelay components tested increased gradually over the period of sporulation, and that Spo0F was expressed in a more heterogeneous pattern than KinA and Spo0B in a sporulating cell population. We determined molecule numbers and concentrations of each phosphorelay component under physiological sporulation conditions at the single-cell level. Based on these results, we suggest that successful entry into the sporulation state is manifested by a certain critical level of each phosphorelay component, and thus that only a subpopulation achieves a sufficient intracellular quorum of the phosphorelay components to activate Spo0A and proceed successfully to the entry into sporulation.
4
Eswaramoorthy, Prahathees, Daniel Duan, Jeffrey Dinh, Ashlee Dravis, Seram Nganbiton Devi und Masaya Fujita. „The Threshold Level of the Sensor Histidine Kinase KinA Governs Entry into Sporulation in Bacillus subtilis“. Journal of Bacteriology 192, Nr. 15 (28.05.2010): 3870–82. http://dx.doi.org/10.1128/jb.00466-10.
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ABSTRACT Sporulation in Bacillus subtilis is controlled by a complex gene regulatory circuit that is activated upon nutrient deprivation. The initial process is directed by the phosphorelay, involving the major sporulation histidine kinase (KinA) and two additional phosphotransferases (Spo0F and Spo0B), that activates the master transcription factor Spo0A. Little is known about the initial event and mechanisms that trigger sporulation. Using a strain in which the synthesis of KinA is under the control of an IPTG (isopropyl-β-d-thiogalactopyranoside)-inducible promoter, here we demonstrate that inducing the synthesis of the KinA beyond a certain level leads to the entry of the irreversible process of sporulation irrespective of nutrient availability. Moreover, the engineered cells expressing KinA under a σH-dependent promoter that is similar to but stronger than the endogenous kinA promoter induce sporulation during growth. These cells, which we designated COS (constitutive sporulation) cells, exhibit the morphology and properties of sporulating cells and express sporulation marker genes under nutrient-rich conditions. Thus, we created an engineered strain displaying two cell cycles (growth and sporulation) integrated into one cycle irrespective of culture conditions, while in the wild type, the appropriate cell fate decision is made depending on nutrient availability. These results suggest that the threshold level of the major sporulation kinase acts as a molecular switch to determine cell fate and may rule out the possibility that the activity of KinA is regulated in response to the unknown signal(s).
5
Caffi, Tito, Giovanna Gilardi, Matteo Monchiero und Vittorio Rossi. „Production and Release of Asexual Sporangia in Plasmopara viticola“. Phytopathology® 103, Nr. 1 (Januar 2013): 64–73. http://dx.doi.org/10.1094/phyto-04-12-0082-r.
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To study the influence of environmental conditions on sporulation of Plasmopara viticola lesions under vineyard's conditions, unsprayed vines were inspected every second or third day and the numbers of sporulating and nonsporulating lesions were counted in two North Italy vineyards in 2008 to 2010. Infected leaves were removed so that only fresh lesions were assessed at each field assessment. Sporulation was studied at two scales, across field assessments and across the seasonal population of lesions. Frequencies of sporulating lesions were positively correlated with the numbers of moist hours in the preceding dark period (i.e., the number of hours between 8:00 p.m. and 7:00 a.m. with relative humidity ≥80%, rainfall >0 mm, or wetness duration >30 min). In a receiver operating characteristic analysis, predicted sporulation based on the occurrence of ≥3 moist hours at night provided overall accuracy of 0.85. To study the time course of sporulation on lesions which were not washed by rainfall, numbers of sporangia produced per square millimeter of lesion were estimated on individual cohorts of lesions over the whole infectious period. The numbers of sporangia per square millimeter of lesion increased rapidly during the first 4 days after the beginning of sporulation and then tapered off prior to a halt; the time course of cumulative sporangia production by a lesion followed a monomolecular growth model (R2 = 0.97). The total number of sporangia produced by a square millimeter of lesion increased as the maximum temperature decreased and moist hours in the dark increased. To study the release pattern of the sporangia, spore samplers were placed near grapevines with sporulating lesions. Airborne sporangia were caught in 91.2% of the days over a wide range of weather conditions, including rainless periods. The results of this study provide quantitative information on production of P. viticola sporangia that may help refine epidemiological models used as decision aids in grape disease management programs.
6
Olempska-Beer, Z., und E. Freese. „Initiation of meiosis and sporulation in Saccharomyces cerevisiae does not require a decrease in cyclic AMP“. Molecular and Cellular Biology 7, Nr. 6 (Juni 1987): 2141–47. http://dx.doi.org/10.1128/mcb.7.6.2141-2147.1987.
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Meiosis and sporulation of Saccharomyces cerevisiae are initiated in a guanine auxotroph by guanine deprivation (E. Bautz Freese, Z. Olempska-Beer, A. Hartig, and E. Freese, Dev. Biol. 102:438-451, 1984). We used this condition to examine a hypothesis (K. Matsumoto, I. Uno, and T. Ishikawa, Cell 32:417-423, 1983) that initiation of meiosis requires a low level of cAMP. We found that, after guanine deprivation, the intracellular concentration of cAMP transiently decreased not more than 20% and not at all if the cAMP phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) was added to the medium. Under these conditions, at least 76% of the cells sporulated in the absence of IBMX, and almost 100% sporulated in its presence. The sporulating cells continually excreted cAMP and utilized the gluconeogenic carbon source. The cells failed to sporulate efficiently and to form four-spored asci if simultaneously deprived of guanine and carbon. After guanine deprivation in glucose medium, sporulation remained suppressed and intracellular cAMP was unchanged. We conclude that, under conditions of guanine starvation, cAMP deficiency is not required for initiation of meiosis and sporulation, cAMP is produced in excess and excreted to the medium, the cells sporulate better if the cAMP concentration is increased by addition of IBMX, the cells require a gluconeogenic carbon source for complete and efficient sporulation, and suppression of sporulation by glucose is not mediated by cAMP.
7
Olempska-Beer, Z., und E. Freese. „Initiation of meiosis and sporulation in Saccharomyces cerevisiae does not require a decrease in cyclic AMP.“ Molecular and Cellular Biology 7, Nr. 6 (Juni 1987): 2141–47. http://dx.doi.org/10.1128/mcb.7.6.2141.
Annotation:
Meiosis and sporulation of Saccharomyces cerevisiae are initiated in a guanine auxotroph by guanine deprivation (E. Bautz Freese, Z. Olempska-Beer, A. Hartig, and E. Freese, Dev. Biol. 102:438-451, 1984). We used this condition to examine a hypothesis (K. Matsumoto, I. Uno, and T. Ishikawa, Cell 32:417-423, 1983) that initiation of meiosis requires a low level of cAMP. We found that, after guanine deprivation, the intracellular concentration of cAMP transiently decreased not more than 20% and not at all if the cAMP phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) was added to the medium. Under these conditions, at least 76% of the cells sporulated in the absence of IBMX, and almost 100% sporulated in its presence. The sporulating cells continually excreted cAMP and utilized the gluconeogenic carbon source. The cells failed to sporulate efficiently and to form four-spored asci if simultaneously deprived of guanine and carbon. After guanine deprivation in glucose medium, sporulation remained suppressed and intracellular cAMP was unchanged. We conclude that, under conditions of guanine starvation, cAMP deficiency is not required for initiation of meiosis and sporulation, cAMP is produced in excess and excreted to the medium, the cells sporulate better if the cAMP concentration is increased by addition of IBMX, the cells require a gluconeogenic carbon source for complete and efficient sporulation, and suppression of sporulation by glucose is not mediated by cAMP.
8
Poletto, Tales, Marlove F. B. Muniz, Vinícius S. Fantinel, Renata F. Favaretto, Igor Poletto, Lia R. S. Reiniger und Elena Blume. „Culture Medium, Light Regime and Temperature Affect the Development of Sirosporium diffusum“. Journal of Agricultural Science 10, Nr. 6 (06.05.2018): 310. http://dx.doi.org/10.5539/jas.v10n6p310.
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Sirosporium diffusum is the causal agent of the brown leaf spot disease on pecan trees that seriously damages the foliage of adult plants and seedlings. This fungal species is difficult to grow satisfactorily in a culture medium. Therefore, the aim of this study was to evaluate the effects of different physical conditions on the development of S. diffusum. In the first assay, eight culture media and five light regimes were combined, while in the second, the three treatments that promoted highest sporulation were combined with three temperatures. The trials were conducted in a two-factorial arrangement in a fully randomized design with six replicates. V8, V8CaCO3, and CA media under a 24-h photoperiod produced the highest respective sporulations: 29 × 104, 35 × 104, and 41 × 104 conidia ml-1. The best temperature for sporulation was 20±1 °C for all culture media, especially V8CaCO3 and CA. The best artificial conditions for obtaining good mycelial growth and sporulation consisted of a photoperiod of 24 h, temperature of 20±1 °C and V8CaCO3 or CA culture medium.
9
FAILLE, CHRISTINE, JEANNE MARIE MEMBRE, MARTINE KUBACZKA und FRANÇOISE GAVINI. „Altered Ability of Bacillus cereus Spores To Grow under Unfavorable Conditions (Presence of Nisin, Low Temperature, Acidic pH, Presence of NaCl) following Heat Treatment during Sporulation“. Journal of Food Protection 65, Nr. 12 (01.12.2002): 1930–36. http://dx.doi.org/10.4315/0362-028x-65.12.1930.
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The effect of thermal treatment on the heat resistance of Bacillus cereus spores and their ability to germinate and grow under more or less adverse conditions during sporulation was investigated. Spores produced by sporulating cells subjected to a mild heat treatment (at a temperature 15°C higher than the growth temperature) were more resistant to heat than were spores produced by untreated cells. Spore germination and growth (the lag time, the maximal growth rate, and the occurrence of a decrease in population) may be greatly affected by adverse environmental conditions brought about by the addition of nisin, low temperatures, acidic pHs, and, to a lesser extent, the addition of NaCl. Furthermore, heat treatments applied to sporulating cells or to mature spores induced a modification of the lag time (interaction of both treatments). Therefore, mild heat treatments applied during sporulation may affect the heat resistance of spores and the ability of these spores to germinate under adverse conditions and may thus increase the risk associated with the presence of spores in lightly processed foods.
10
Kaback, D. B., und L. R. Feldberg. „Saccharomyces cerevisiae exhibits a sporulation-specific temporal pattern of transcript accumulation“. Molecular and Cellular Biology 5, Nr. 4 (April 1985): 751–61. http://dx.doi.org/10.1128/mcb.5.4.751-761.1985.
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Cultures of the yeast Saccharomyces cerevisiae that are heterozygous for the mating type (MATa/MAT alpha) undergo synchronous meiosis and spore formation when starved for nitrogen and supplied with a nonfermentable carbon source such as acetate. Haploid and homozygous MAT alpha/MAT alpha and MATa/MATa diploid cells incubated under the same conditions fail to undergo meiosis and are asporogenous. It has not yet been firmly established that gene expression during sporulation is controlled at the level of transcript accumulation. To examine this question, we used cloned genes that encode a variety of "housekeeping" functions to probe Northern blots to assay the appearance of specific transcripts in both sporulating and asporogenous S. cerevisiae. In sporulating cells, each transcript showed a characteristic pattern of accumulation, reaching a maximum relative abundance at one of several different periods. In contrast, in both asporogenous haploid MATa and diploid MAT alpha/MAT alpha cells, all transcripts accumulated with similar kinetics. These results suggest a sporulation-specific pattern for transcript appearance. During these studies, high levels of several different transcripts were observed at unexpected times in sporulating cells. Histone (H)2A and (H)2B1 transcripts, although most abundant during premeiotic DNA synthesis, remained at one-third to one-half maximal levels after its end and were found in mature ascospores. Their appearance at this time is in sharp contrast to vegetative cells in which these histone transcripts are only found just before and during the period of DNA synthesis. Furthermore, transcripts from GAL10 and CDC10 genes, which are believed to be dispensable for sporulation, were much more abundant in sporulating cells than in asporogenous cells and vegetative cells grown on glucose or acetate. The presence of these transcripts did not appear to be due to a general activation of transcription because each accumulated with different kinetics. In addition, the transcript for at least one gene, HO, that is also dispensable for sporulation was not detected. The increased abundance of transcripts from some genes not required for sporulation leads us to propose that genes preferentially expressed during sporulation need not be essential for this differentiation.
11
Kaback, D. B., und L. R. Feldberg. „Saccharomyces cerevisiae exhibits a sporulation-specific temporal pattern of transcript accumulation.“ Molecular and Cellular Biology 5, Nr. 4 (April 1985): 751–61. http://dx.doi.org/10.1128/mcb.5.4.751.
Annotation:
Cultures of the yeast Saccharomyces cerevisiae that are heterozygous for the mating type (MATa/MAT alpha) undergo synchronous meiosis and spore formation when starved for nitrogen and supplied with a nonfermentable carbon source such as acetate. Haploid and homozygous MAT alpha/MAT alpha and MATa/MATa diploid cells incubated under the same conditions fail to undergo meiosis and are asporogenous. It has not yet been firmly established that gene expression during sporulation is controlled at the level of transcript accumulation. To examine this question, we used cloned genes that encode a variety of "housekeeping" functions to probe Northern blots to assay the appearance of specific transcripts in both sporulating and asporogenous S. cerevisiae. In sporulating cells, each transcript showed a characteristic pattern of accumulation, reaching a maximum relative abundance at one of several different periods. In contrast, in both asporogenous haploid MATa and diploid MAT alpha/MAT alpha cells, all transcripts accumulated with similar kinetics. These results suggest a sporulation-specific pattern for transcript appearance. During these studies, high levels of several different transcripts were observed at unexpected times in sporulating cells. Histone (H)2A and (H)2B1 transcripts, although most abundant during premeiotic DNA synthesis, remained at one-third to one-half maximal levels after its end and were found in mature ascospores. Their appearance at this time is in sharp contrast to vegetative cells in which these histone transcripts are only found just before and during the period of DNA synthesis. Furthermore, transcripts from GAL10 and CDC10 genes, which are believed to be dispensable for sporulation, were much more abundant in sporulating cells than in asporogenous cells and vegetative cells grown on glucose or acetate. The presence of these transcripts did not appear to be due to a general activation of transcription because each accumulated with different kinetics. In addition, the transcript for at least one gene, HO, that is also dispensable for sporulation was not detected. The increased abundance of transcripts from some genes not required for sporulation leads us to propose that genes preferentially expressed during sporulation need not be essential for this differentiation.
12
Graat, E. A. M., A. M. Henken, H. W. Ploeger, J. P. T. M. Noordhuizen und M. H. Vertommen. „Rate and course of sporulation of oocysts ofEimeria acervulinaunder different environmental conditions“. Parasitology 108, Nr. 5 (Juni 1994): 497–502. http://dx.doi.org/10.1017/s0031182000077350.
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SummaryAn experiment was conducted to determine the rate and maximum percentage of sporulation ofEimeria acervulinaoocysts at various environmental conditions relating to temperature (21 versus 33 °C) and relative humidity (RH) (40 versus 80%). Measurements were made during 44 h after excretion of oocysts in 3 substrates: dry litter, clammy litter and pure faeces respectively. Maximum sporulation percentage in both dry (22·6%) and clammy litter (19·5%) was higher (P< 0·005) than in pure faeces (11·6%). Neither temperature nor RH had a significant influence on percentage of oocysts that sporulated. Under these simulated practical conditions approximately 25% of all oocysts sporulated, whereas sporulation under optimal conditions (29 °C, aeration, 2% K2Cr2O7) showed a higher (68%) sporulation ability of oocysts. At 33 °C sporulation proceeded at a faster pace than at 21 °C (P< 0·005). With respect to RH and substrate, once sporulation started, the rate of increase to maximum percentage was not different. Time of onset of sporulation was influenced by temperature (P< 0·0001) and RH (P< 0·001). Time of onset occurred 15 h later at 21 °C compared with 33 °C and 5 h later at 40% RH compared with 80%. Also, an interaction effect (P< 0·01) was found with effect of RH being stronger at 21 °C compared with 33 °C. It was concluded that the most important aspect in the epidemiology ofE. acervulinaduring a flock cycle is the time of onset of sporulation with temperature being the most important factor.
13
Su, H., A. H. C. van Bruggen, K. V. Subbarao und H. Scherm. „Sporulation of Bremia lactucae Affected by Temperature, Relative Humidity, and Wind in Controlled Conditions“. Phytopathology® 94, Nr. 4 (April 2004): 396–401. http://dx.doi.org/10.1094/phyto.2004.94.4.396.
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The effects of temperature (5 to 25°C), relative humidity (81 to 100%), wind speed (0 to 1.0 m s-1), and their interactions on sporulation of Bremia lactucae on lettuce cotyledons were investigated in controlled conditions. Sporulation was affected significantly (P < 0.0001) by temperature, with an optimum at 15°C, and by relative humidity (RH), with sporulation increasing markedly at RH ≥ 90%. There was a significant effect of exposure time in relation to temperature (P = 0.0007) but not to RH. In separate experiments, both RH and wind speed significantly (P < 0.0001) affected the number of cotyledons with sporulation and the number of sporangia produced per cotyledon. No sporulation was observed at wind speeds of >0.5 m s-1, regardless of RH. In still air, the number of sporangiophores produced per cotyledon increased linearly with RH from 81 to 100% (P = 0.0001, r = 0.98). Histological observations indicated that sporulation may be affected by stomatal aperture in response to RH, as more closed stomata and correspondingly fewer sporangiophores were present at lower RH. These results are important for understanding the mechanism of RH effects on sporulation and for predicting conditions conducive to downy mildew development.
14
Decaudin, Mathilde, und Jean-Luc Tholozan. „A comparative study on the conditions of growth and sporulation of three strains of Clostridium petfringens type A“. Canadian Journal of Microbiology 42, Nr. 3 (01.03.1996): 298–304. http://dx.doi.org/10.1139/m96-044.
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Different conditions of growth and sporulation of a strain of Clostridium perfringens type A (NCTC 8798) and two derived mutant strains, the lysozyme-germination dependent strain 8-6 and the revertant strain R3, have been determined. No sporulation was detected for the three strains in the Duncan and Strong (DS) medium; 100% sporulation was routinely obtained for the two mutant strains in the defined (D) medium. Factors promoting in vitro sporulation of C. perfringens type A were assayed: the volume of the culture, the type of preculture, and the addition of lysozyme in precultures. The paper also provides additional information on growth and sporulation of the mutant strains 8-6 and R3. Glucose concentrations up to 11 mM produced high percentages of sporulation. However, strain R3 still sporulated at 20% with 56 mM of glucose. A high volume of D medium led to slow growth kinetics and favoured sporulation. Faster kinetics of growth and the best percentage of sporulation were obtained with a young inoculum of the two mutant strains. On the other hand, the type of medium in the preculture (fluid thioglycollate (FTG) or basal carbonate yeast trypticase (BCYT)) did not influence the percentage of sporulation. However, while strain R3 was not affected by the addition of lysozyme in D medium, kinetics of growth were strongly influenced by this addition in strain 8-6, and the percentage of sporulation increased with a preculture in FTG medium and decreased when BCYT medium was used.Key words: Clostridium perfringens, medium, growth, sporulation.
15
Filgueira D., Juan José, und Angélica Zambrano. „Temperature effect on rose downy mildew development under environmental controlled conditions“. Agronomía Colombiana 32, Nr. 1 (01.01.2014): 29–35. http://dx.doi.org/10.15446/agron.colomb.v32n1.41362.
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The rose downy mildew disease, caused by Peronospora sparsa Berkeley, is one of the most important that affect rose crops in Colombia. To manage this disease, flower growers must deal with high-costs due to the excessive application of fungicides, but without good results. Studies on P. sparsa behavior have shown its narrow relationship with environmental conditions. In this study, the temperature effect was evaluated during the infection and sporulation of P. sparsa in Charlotte leaflets, a susceptible commercial variety, through an environmental controlled conditions system. Infection and sporulation were observed at different temperatures in a range of from 4 to 40°C. Infection with the absence of or very low sporulation was observed at 4°C. The most favorable pathogen responses were between 15 and 18°C in terms of inoculum concentration and sporulation percentage. There was no infection or leaflet change above 35°C. According to the results, sporulation can occur from 4 to 33°C, confirming the fact that P. sparsa is able to reproduce throughout a wide temperature range.
16
Ufano, Sandra, Pedro San-Segundo, Francisco del Rey und Carlos R. Vázquez de Aldana. „SWM1, a Developmentally Regulated Gene, Is Required for Spore Wall Assembly in Saccharomyces cerevisiae“. Molecular and Cellular Biology 19, Nr. 3 (01.03.1999): 2118–29. http://dx.doi.org/10.1128/mcb.19.3.2118.
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ABSTRACT Meiosis in Saccharomyces cerevisiae is followed by encapsulation of haploid nuclei within multilayered spore walls. Formation of this spore-specific wall requires the coordinated activity of enzymes involved in the biosynthesis of its components. Completion of late events in the sporulation program, leading to spore wall formation, requires the SWM1 gene.SWM1 is expressed at low levels during vegetative growth but its transcription is strongly induced under sporulating conditions, with kinetics similar to those of middle sporulation-specific genes. Homozygous swm1Δ diploids proceed normally through both meiotic divisions but fail to produce mature asci. Consistent with this finding, swm1Δ mutant asci display enhanced sensitivity to enzymatic digestion and heat shock. Deletion ofSWM1 specifically affects the expression of mid-late and late sporulation-specific genes. All of the phenotypes observed are similar to those found for the deletion of SPS1 orSMK1, two putative components of a sporulation-specific MAP kinase cascade. However, epistasis analyses indicate that Swm1p does not form part of the Sps1p-Smk1p-MAP kinase pathway. We propose that Swm1p, a nuclear protein, would participate in a different signal transduction pathway that is also required for the coordination of the biochemical and morphological events occurring during the last phase of the sporulation program.
17
Shih, Neng-Jen, und Ronald G. Labbé. „Characterization and distribution of amylases during vegetative cell growth and sporulation ofClostridium perfringens“. Canadian Journal of Microbiology 42, Nr. 7 (01.07.1996): 628–33. http://dx.doi.org/10.1139/m96-086.
Annotation:
Clostridium perfringens produced eight extracellular and two intracellular amylolytic activities when examined by zymograms following polyacrylamide gel electrophoresis under native conditions. The major intracellular amylase was isolated from vegetative cells of C. perfringens. It possessed an estimated molecular mass of 112 kDa. Sulfhydryl and phenol functional groups were essential to its activity. The amylase was endo-acting on starch and also hydrolyzed pullulan. Polyclonal antisera against a purified extracellular amylase did not cross-react with intracellular amylase and the two amylases were biochemically different. The distribution of extracellular amylolytic activities of sporulating cells was different from that of vegetative cells, whereas the distribution of intracellular amylolytic activities remained identical. A significant increase of a particular amylase (A8) occurred in the extracellular fluid during sporulation compared with that during vegetative growth. Regulation of the excretion of amylase(s) may be sporulation and enterotoxingenicity related.Key words: Clostridium perfringens, amylase, sporulation.
18
Jakubowski, H., und E. Goldman. „Evidence for cooperation between cells during sporulation of the yeast Saccharomyces cerevisiae“. Molecular and Cellular Biology 8, Nr. 12 (Dezember 1988): 5166–78. http://dx.doi.org/10.1128/mcb.8.12.5166-5178.1988.
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Diploid Saccharomyces cerevisiae cells heterozygous for the mating type locus (MATa/MAT alpha) undergo meiosis and sporulation when starved for nitrogen in the presence of a poor carbon source such as potassium acetate. Diploid yeast adenine auxotrophs sporulated well at high cell density (10(7) cells per ml) under these conditions but failed to differentiate at low cell density (10(5) cells per ml). The conditional sporulation-deficient phenotype of adenine auxotrophs could be complemented by wild-type yeast cells, by medium from cultures that sporulate at high cell density, or by exogenously added adenine (or hypoxanthine with some mutants). Adenine and hypoxanthine in addition to guanine, adenosine, and numerous nucleotides were secreted into the medium, each in its unique temporal pattern, by sporulating auxotrophic and prototrophic yeast strains. The major source of these compounds was degradation of RNA. The data indicated that differentiating yeast cells cooperate during sporulation in maintaining sufficiently high concentrations of extracellular purines which are absolutely required for sporulation of adenine auxotrophs. Yeast prototrophs, which also sporulated less efficiently at low cell density (10(3) cells per ml), reutilized secreted purines in preference to de novo-made purine nucleotides whose synthesis was in fact inhibited during sporulation at high cell density. Adenine enhanced sporulation of yeast prototrophs at low cell density. The behavior of adenine auxotrophs bearing additional mutations in purine salvage pathway genes (ade apt1, ade aah1 apt1, ade hpt1) supports a model in which secretion of degradation products, uptake, and reutilization of these products is a signal between cells synchronizing the sporulation process.
19
Jakubowski, H., und E. Goldman. „Evidence for cooperation between cells during sporulation of the yeast Saccharomyces cerevisiae.“ Molecular and Cellular Biology 8, Nr. 12 (Dezember 1988): 5166–78. http://dx.doi.org/10.1128/mcb.8.12.5166.
Annotation:
Diploid Saccharomyces cerevisiae cells heterozygous for the mating type locus (MATa/MAT alpha) undergo meiosis and sporulation when starved for nitrogen in the presence of a poor carbon source such as potassium acetate. Diploid yeast adenine auxotrophs sporulated well at high cell density (10(7) cells per ml) under these conditions but failed to differentiate at low cell density (10(5) cells per ml). The conditional sporulation-deficient phenotype of adenine auxotrophs could be complemented by wild-type yeast cells, by medium from cultures that sporulate at high cell density, or by exogenously added adenine (or hypoxanthine with some mutants). Adenine and hypoxanthine in addition to guanine, adenosine, and numerous nucleotides were secreted into the medium, each in its unique temporal pattern, by sporulating auxotrophic and prototrophic yeast strains. The major source of these compounds was degradation of RNA. The data indicated that differentiating yeast cells cooperate during sporulation in maintaining sufficiently high concentrations of extracellular purines which are absolutely required for sporulation of adenine auxotrophs. Yeast prototrophs, which also sporulated less efficiently at low cell density (10(3) cells per ml), reutilized secreted purines in preference to de novo-made purine nucleotides whose synthesis was in fact inhibited during sporulation at high cell density. Adenine enhanced sporulation of yeast prototrophs at low cell density. The behavior of adenine auxotrophs bearing additional mutations in purine salvage pathway genes (ade apt1, ade aah1 apt1, ade hpt1) supports a model in which secretion of degradation products, uptake, and reutilization of these products is a signal between cells synchronizing the sporulation process.
20
Stöver, Axel G., und Adam Driks. „Secretion, Localization, and Antibacterial Activity of TasA, a Bacillus subtilis Spore-Associated Protein“. Journal of Bacteriology 181, Nr. 5 (01.03.1999): 1664–72. http://dx.doi.org/10.1128/jb.181.5.1664-1672.1999.
Annotation:
ABSTRACT The synthesis and subcellular localization of the proteins that comprise the Bacillus subtilis spore are under a variety of complex controls. To better understand these controls, we have identified and characterized a 31-kDa sporulation protein, called TasA, which is secreted into the culture medium early in sporulation and is also incorporated into the spore. TasA synthesis begins approximately 30 min after the onset of sporulation and requires the sporulation transcription factor genes spo0H and spo0A. The first 81 nucleotides of tasA encode a 27-amino-acid sequence that resembles a signal peptide and which is missing from TasA isolated from a sporulating cell lysate. In B. subtiliscells unable to synthesize the signal peptidase SipW, TasA is not secreted, nor is it incorporated into spores. Cells unable to produce SipW produce a 34-kDa form of TasA, consistent with a failure to remove the N-terminal 27 amino acids. In cells engineered to expresssipW and tasA during exponential growth, TasA migrates as a 31-kDa species and is secreted into the culture medium. These results indicate that SipW plays a crucial role in the export of TasA out of the cell and its incorporation into spores. Although TasA is dispensable for sporulation under laboratory conditions, we find that TasA has a broad-spectrum antibacterial activity. We discuss the possibility that during the beginning of sporulation as well as later, during germination, TasA inhibits other organisms in the environment, thus conferring a competitive advantage to the spore.
21
Simchen, Giora, und Yona Kassir. „Genetic regulation of differentiation towards meiosis in the yeast Saccharomyces cerevisiae“. Genome 31, Nr. 1 (01.01.1989): 95–99. http://dx.doi.org/10.1139/g89-018.
Annotation:
Normally, meiosis and sporulation in Saccharomyces cerevisiae occur only in diploid strains and only when the cells are exposed to starvation conditions. Diploidy is determined by the mating-type system (the genes MAT, RME1, IME1), whereas the starvation signal is transmitted through the adenylate cyclase – protein kinase pathway (the genes CDC25, RAS2, CDC35 (CYR1), BCY1, TPK1, TPK2, TPK3). The two regulatory pathways converge at the gene IME1, which is a positive regulator of meiosis and whose early expression in sporulating cells correlates with the initiation of meiosis. Sites upstream (5′) of IME1 appear to mediate in the repression of the gene by repressors originating from both the mating-type and the cyclase – kinase pathways.Key words: sporulation, mating type, diploidy, adenylate cyclase, cAMP, protein kinase.
22
Sinnelä, Martti, Young Park, Jae Lee, KwangCheol Jeong, Young-Wan Kim, Han-Joon Hwang und Jae-Hyung Mah. „Effects of Calcium and Manganese on Sporulation of Bacillus Species Involved in Food Poisoning and Spoilage“. Foods 8, Nr. 4 (07.04.2019): 119. http://dx.doi.org/10.3390/foods8040119.
Annotation:
Spores are resistant against many extreme conditions including the disinfection and sterilization methods used in the food industry. Selective prevention of sporulation of Bacillus species is an ongoing challenge for food scientists and fermentation technologists. This study was conducted to evaluate the effects of single and combined supplementation of calcium and manganese on sporulation of common pathogenic and food spoilage Bacillus species: B. cereus, B. licheniformis, B. subtilis and B. coagulans. Sporulation of Bacillus vegetative cells was induced on sporulation media supplemented with diverse concentrations of the minerals. Under the various mineral supplementation conditions, the degree of sporulation was quantified with colonies formed by the Bacillus spores. The results revealed that B. licheniformis and B. cereus displayed the weakest sporulation capabilities on media with minimal supplementation levels of calcium and manganese. The lowest sporulation of B. subtilis and B. coagulans was observed on media supplemented with the highest level of calcium and low levels of manganese. Depending on effect of supplementation on sporulation, the Bacillus species were divided into two distinct groups: B. licheniformis and B. cereus; and B. subtilis and B. coagulans. The information provides valuable insight to selectively reduce sporulation of Bacillus species undesirable in the food industry.
23
Birkey, Stephanie M., Guofu Sun, P. J. Piggot und F. Marion Hulett. „A pho regulon promoter induced under sporulation conditions“. Gene 147, Nr. 1 (September 1994): 95–100. http://dx.doi.org/10.1016/0378-1119(94)90045-0.
24
Kumar, D., SL Godara und MK Sheshma. „Physiological studies on Alternaria porri caused purple blotch of onion under In-vitro conditions“. Journal of Agriculture and Ecology 17 (31.12.2023): 109–12. http://dx.doi.org/10.58628/jae-2317-320.
Annotation:
The effect of nutrient media, temperature, pH level, carbon and nitrogen ion concentration were studied on mycelial growth and sporulation of Alternaria porri caused purple blotch of onion. The investigations revealed that Potato dextrose agar was the best culture medium for A. porri. The maximum mycelial growth of A. porri was recorded on 30°C temperature (85.74 mm) and pH 7.0 (83.40 mm). A. porri grew significantly better response to the source of carbon nutrient media on mycelial growth and observed the maximum mycelial growth on maltose (88.26 mm) based medium with highest sporulation and potassium nitrate-based media source of nitrogen gave maximum mycelial growth (80.75 mm) and sporulation of A. porri. The present findings are useful for the preparation of inoculums required for resistance breeding and fungicidal evaluation against pathogen A. porri.
25
Gottlin-Ninfa, E., und D. B. Kaback. „Isolation and functional analysis of sporulation-induced transcribed sequences from Saccharomyces cerevisiae“. Molecular and Cellular Biology 6, Nr. 6 (Juni 1986): 2185–97. http://dx.doi.org/10.1128/mcb.6.6.2185-2197.1986.
Annotation:
Strains of the yeast Saccharomyces cerevisiae that are heterozygous for the mating-type locus (MATa/MAT alpha) undergo meiosis and spore formation when they are starved for nitrogen and are provided with a nonfermentable carbon source such as potassium acetate. Haploids and diploids homozygous for the mating-type locus (MAT alpha/MAT alpha or MATa/MATa) are asporogenous and undergo neither meiosis nor spore formation when incubated under the same conditions. A small number of genes produce transcripts that appear to be induced specifically in sporulating cells. These transcripts either are not found or are present at much lower levels both in vegetatively growing cells and in cells from asporogenous strains that have been incubated in sporulation medium. Several genes complementary to these MATa/MAT alpha-dependent sporulation-induced transcripts were isolated from a gene-size insert yeast-lambda recombinant DNA library, by differential-plaque filter hybridization. An attempt was made to determine the function of three of these genes by mutating them in the yeast genome with in vitro mutagenesis and one-step gene replacement techniques. One gene was extensively disrupted by both a 0.3-kilobase deletion and the insertion of two large DNA sequences at different sites within the gene. Surprisingly, this compound mutation did not appear to affect meiosis or the production of viable ascospores, indicating that this gene was dispensable for differentiation. The other two genes were disrupted by simple insertion mutations at a site where it was possible that they might still possess some gene activity. These mutations also did not appear to affect sporulation. These results suggest that not all sporulation-induced genes are essential for meiosis and the production of viable ascospores under the conditions examined.
26
Gottlin-Ninfa, E., und D. B. Kaback. „Isolation and functional analysis of sporulation-induced transcribed sequences from Saccharomyces cerevisiae.“ Molecular and Cellular Biology 6, Nr. 6 (Juni 1986): 2185–97. http://dx.doi.org/10.1128/mcb.6.6.2185.
Annotation:
Strains of the yeast Saccharomyces cerevisiae that are heterozygous for the mating-type locus (MATa/MAT alpha) undergo meiosis and spore formation when they are starved for nitrogen and are provided with a nonfermentable carbon source such as potassium acetate. Haploids and diploids homozygous for the mating-type locus (MAT alpha/MAT alpha or MATa/MATa) are asporogenous and undergo neither meiosis nor spore formation when incubated under the same conditions. A small number of genes produce transcripts that appear to be induced specifically in sporulating cells. These transcripts either are not found or are present at much lower levels both in vegetatively growing cells and in cells from asporogenous strains that have been incubated in sporulation medium. Several genes complementary to these MATa/MAT alpha-dependent sporulation-induced transcripts were isolated from a gene-size insert yeast-lambda recombinant DNA library, by differential-plaque filter hybridization. An attempt was made to determine the function of three of these genes by mutating them in the yeast genome with in vitro mutagenesis and one-step gene replacement techniques. One gene was extensively disrupted by both a 0.3-kilobase deletion and the insertion of two large DNA sequences at different sites within the gene. Surprisingly, this compound mutation did not appear to affect meiosis or the production of viable ascospores, indicating that this gene was dispensable for differentiation. The other two genes were disrupted by simple insertion mutations at a site where it was possible that they might still possess some gene activity. These mutations also did not appear to affect sporulation. These results suggest that not all sporulation-induced genes are essential for meiosis and the production of viable ascospores under the conditions examined.
27
Traag, Bjorn A., Antonia Pugliese, Jonathan A. Eisen und Richard Losick. „Gene Conservation among Endospore-Forming Bacteria Reveals Additional Sporulation Genes in Bacillus subtilis“. Journal of Bacteriology 195, Nr. 2 (02.11.2012): 253–60. http://dx.doi.org/10.1128/jb.01778-12.
Annotation:
ABSTRACTThe capacity to form endospores is unique to certain members of the low-G+C group of Gram-positive bacteria (Firmicutes) and requires signature sporulation genes that are highly conserved across members of distantly related genera, such asClostridiumandBacillus. Using gene conservation among endospore-forming bacteria, we identified eight previously uncharacterized genes that are enriched among endospore-forming species. The expression of five of these genes was dependent on sporulation-specific transcription factors. Mutants of none of the genes exhibited a conspicuous defect in sporulation, but mutants of two,ylxYandylyA, were outcompeted by a wild-type strain under sporulation-inducing conditions, but not during growth. In contrast, aylmCmutant displayed a slight competitive advantage over the wild type specific to sporulation-inducing conditions. The phenotype of aylyAmutant was ascribed to a defect in spore germination efficiency. This work demonstrates the power of combining phylogenetic profiling with reverse genetics and gene-regulatory studies to identify unrecognized genes that contribute to a conserved developmental process.
28
Latgé, J. P., und J. J. Sanglier. „Optimisation de la croissance et de la sporulation de Conidiobolus obscurus en milieu défini“. Canadian Journal of Botany 63, Nr. 1 (01.01.1985): 68–85. http://dx.doi.org/10.1139/b85-011.
Annotation:
Physical and nutritional factors influencing the growth and sporulation of Conidiobolus obscurus (Hall et Dunn) Remaudière et Keller were studied using simple and fragmented factorial designs and centered composite designs. Culture conditions allowing maximum sporulation were a temperature of 20 °C, complete darkness, and a near neutral pH of around 6.5. Under our experimental conditions, dextrose influenced neither the growth nor the sporulation of C. obscurus. The cations stimulating the formation of azygospores were magnesium and to a lesser extent zinc and manganese. Sulphur must be added to the medium in a reduced or oxydized form. Phosphates must be present in the culture medium, but at a concentration less than 30 mM/L. Vitamins stimulating sporulation were thiamine, biotin, and folic acid while pantothenic acid favoured growth. Among the 20 amino acids tested, proline, leucine, methionine, glutamic and aspartic acids, glutamine, asparagine, histidine, phenylalanine, lysine, and arginine were the most favourable for growth and sporulation of C. obscurus. Growth and sporulation in the optimized defined medium containing 11 amino acids, four vitamins, four salts, and dextrose were comparable to the best results obtained in a nondefined medium composed of dextrose and yeast extract.
29
Sawyer, A. J., M. E. Ramos, T. J. Poprawski, R. S. Soper und R. I. Carruthers. „SEASONAL PATTERNS OF CADAVER PERSISTENCE AND SPORULATION BY THE FUNGAL PATHOGEN ENTOMOPHAGA GRYLLI (FRESENIUS) BATKO (ENTOMOPHTHORALES: ENTOMOPHTHORACEAE) INFECTING CAMNULA PELLUCIDA (SCUDDER) (ORTHOPTERA: ACRIDIDAE)“. Memoirs of the Entomological Society of Canada 129, S171 (1997): 355–74. http://dx.doi.org/10.4039/entm129171355-1.
Annotation:
AbstractEntomophaga grylli (Fresenius) Batko (North American pathotype 1) is a fungal pathogen of the clearwinged grasshopper, Camnula pellucida (Scudder). We present results from a field experiment conducted in Arizona in 1984, designed to investigate factors associated with seasonal patterns of cadaver persistence and sporulation by E. grylli. Rangeland plots at two sites were monitored daily for 8 weeks for the appearance of new cadavers of diseased grasshoppers during a natural epizootic. Cadavers were individually marked and revisited on subsequent days, when it was noted whether or not conidial sporulation was underway. Environmental variables were recorded by electronic data loggers. Daily probabilities of cadaver disappearance and fungal sporulation were analysed in relation to site, date, and various measures of cadaver status, sporulation history, and environmental variables by logistic regression analysis. The average daily rate of cadaver disappearance was 0.22, yielding an expected time to 50% disappearance of 2.8 days. The environmental factor most significantly associated with cadaver disappearance was rainfall, and the most important host factor was age of the cadaver. The probability that conidia would be discharged from a cadaver over the next 24 h was most dependent on whether or not conidial sporulation was underway already. This probably reflects a state of readiness for sporulation on the part of the fungus. Although the probability of sporulation declined with increasing age of a cadaver, high rates of sporulation were predicted under conditions of prolonged leaf wetness and high humidity at night, regardless of age of the cadaver. These results, together with the observation that in some cadavers sequences of sporulation were interspersed with periods of no sporulation, suggest that E. grylli may undergo cycles of dehydration and rehydration, in which conidial production is interrupted and then resumes in response to changing environmental conditions.
30
de Vries, Ynte P., Ratna D. Atmadja, Luc M. Hornstra, Willem M. de Vos und Tjakko Abee. „Influence of Glutamate on Growth, Sporulation, and Spore Properties of Bacillus cereus ATCC 14579 in Defined Medium“. Applied and Environmental Microbiology 71, Nr. 6 (Juni 2005): 3248–54. http://dx.doi.org/10.1128/aem.71.6.3248-3254.2005.
Annotation:
ABSTRACT A chemically defined medium in combination with an airlift fermentor system was used to study the growth and sporulation of Bacillus cereus ATCC 14579. The medium contained six amino acids and lactate as the main carbon sources. The amino acids were depleted during exponential growth, while lactate was metabolized mainly during stationary phase. Two concentrations of glutamate were used: high (20 mM; YLHG) and low (2.5 mM; YLLG). Under both conditions, sporulation was complete and synchronous. Sporulation started and was completed while significant amounts of carbon and nitrogen sources were still present in the medium, indicating that starvation was not the trigger for sporulation. Analysis of amino acids and NH4 + in the culture supernatant showed that most of the nitrogen assimilated by the bacteria was taken up during sporulation. The consumption of glutamate depended on the initial concentration; in YLLG, all of the glutamate was used early during exponential growth, while in YLHG, almost all of the glutamate was used during sporulation. In YLLG, but not in YLHG, NH4 + was taken up by the cells during sporulation. The total amount of nitrogen used by the bacteria in YLLG was less than that used by the bacteria in YLHG, although a significant amount of NH4 + was present in the medium throughout sporulation. Despite these differences, growth and temporal expression of key sigma factors involved in sporulation were parallel, indicating that the genetic time frames of sporulation were similar under both conditions. Nevertheless, in YLHG, dipicolinic acid production started later and the spores were released from the mother cells much later than in YLLG. Notably, spores had a higher heat resistance when obtained after growth in YLHG than when obtained after growth in YLLG, and the spores germinated more rapidly and completely in response to inosine, l-alanine, and a combination of these two germinants.
31
Tribelhorn, Katharina, Magdalena Twarużek, Ewelina Soszczyńska, Jörg Rau, Christiane Baschien, Reinhard K. Straubinger, Frank Ebel und Sebastian Ulrich. „Production of Satratoxin G and H Is Tightly Linked to Sporulation in Stachybotrys chartarum“. Toxins 14, Nr. 8 (28.07.2022): 515. http://dx.doi.org/10.3390/toxins14080515.
Annotation:
Stachybotrys chartarum is a toxigenic fungus that is frequently isolated from damp building materials or improperly stored forage. Macrocyclic trichothecenes and in particular satratoxins are the most potent mycotoxins known to be produced by this fungus. Exposure of humans or animals to these secondary metabolites can be associated with severe health problems. To assess the pathogenic potential of S. chartarum isolates, it is essential to cultivate them under conditions that reliably promote toxin production. Potato dextrose agar (PDA) was reported to be the optimal nutrition medium for satratoxin production. In this study, the growth of S. chartarum genotype S strains on PDA from two manufacturers led to divergent results, namely, well-grown and sporulating cultures with high satratoxin concentrations (20.8 ± 0.4 µg/cm2) versus cultures with sparse sporulation and low satratoxin production (0.3 ± 0.1 µg/cm2). This finding is important for any attempt to identify toxigenic S. chartarum isolates. Further experiments performed with the two media provided strong evidence for a link between satratoxin production and sporulation. A comparison of three-point and one-point cultures grown on the two types of PDA, furthermore, demonstrated an inter-colony communication that influences both sporulation and mycotoxin production of S. chartarum genotype S strains.
32
Tian, Zhiliang, Lizhen Hou, Miao Hu, Yaxin Gao, Danfeng Li, Bei Fan, Fengzhong Wang und Shuying Li. „Optimization of Sporulation Conditions for Bacillus subtilis BSNK-5“. Processes 10, Nr. 6 (06.06.2022): 1133. http://dx.doi.org/10.3390/pr10061133.
Annotation:
Bacillus subtilis spores have important biological applications; however, high spore-cell densities and sporulation efficiencies in fermentation is poorly reported. This study systematically analyzed the spore densities and formation efficiency of B. subtilis BSNK-5 in different culture substrates. A response surface regression equation was established based on the results of single factor and Box–Behnken experimental designs. The optimal medium formulation, as predicted from the equation, consisted of soluble starch at 3 g·L−1, soybean flour at 12 g·L−1, and MgSO4 at 5 g·L−1. The spore yield reached 2.43 × 109 CFU·mL−1, and the sporulation rate was 83.3%, which was nearly three times higher than before optimization using an optimized medium at 36 °C and 200 rpm for 60 h.
33
Wasserstrom, Lisa, Klaus Lengeler, Andrea Walther und Jürgen Wendland. „Developmental Growth Control Exerted via the Protein A Kinase Tpk2 in Ashbya gossypii“. Eukaryotic Cell 14, Nr. 6 (10.04.2015): 593–601. http://dx.doi.org/10.1128/ec.00045-15.
Annotation:
ABSTRACT Sporulation in Ashbya gossypii is induced by nutrient-limited conditions and leads to the formation of haploid spores. Using RNA-seq, we have determined a gene set induced upon sporulation, which bears considerable overlap with that of Saccharomyces cerevisiae but also contains A. gossypii -specific genes. Addition of cyclic AMP (cAMP) to nutrient-limited media blocks sporulation and represses the induction of sporulation specific genes. Deletion of the protein kinase A (PKA) catalytic subunits encoded by TPK1 and TPK2 showed reduced growth in tpk1 but enhanced growth in the tpk2 strain; however, both mutants sporulated well. Sporulation can be blocked by cAMP in tpk1 but not in tpk2 strains. Similarly, TPK2 acts at a second developmental switch promoting the break in spore dormancy. In S. cerevisiae , PKA phosphorylates and inhibits Msn2/4. The transcript profiles of the tpk1 and msn2/4 mutants were very similar to that of the wild type under sporulation conditions. However, deletion of the single A. gossypii MSN2/4 homolog generated a specific sporulation defect. We identified a set of genes involved in spore wall assembly that was downregulated in the msn2/4 mutant, particularly DIT2 , suggesting that poor spore viability may be due to lysis of spores. Our results reveal specific functional differences between the two catalytic PKA subunits in A. gossypii and identified Tpk2 as the key A kinase that transduces developmental decisions of growth. Our data also suggest that Msn2/4 is involved only at a late step of sporulation in A. gossypii and is not a major regulator of IME1 .
34
Neiman, Aaron M., Luba Katz und Patrick J. Brennwald. „Identification of Domains Required for Developmentally Regulated SNARE Function in Saccharomyces cerevisiae“. Genetics 155, Nr. 4 (01.08.2000): 1643–55. http://dx.doi.org/10.1093/genetics/155.4.1643.
Annotation:
Abstract Saccharomyces cerevisiae cells contain two homologues of the mammalian t-SNARE protein SNAP-25, encoded by the SEC9 and SPO20 genes. Although both gene products participate in post-Golgi vesicle fusion events, they cannot substitute for one another; Sec9p is active primarily in vegetative cells while Spo20p functions only during sporulation. We have investigated the basis for the developmental stage-specific differences in the function of these two proteins. Localization of the other plasma membrane SNARE subunits, Ssop and Sncp, in sporulating cells suggests that these proteins act in conjunction with Spo20p in the formation of the prospore membrane. In vitro binding studies demonstrate that, like Sec9p, Spo20p binds specifically to the t-SNARE Sso1p and, once bound to Sso1p, can complex with the v-SNARE Snc2p. Therefore, Sec9p and Spo20p interact with the same binding partners, but developmental conditions appear to favor the assembly of complexes with Spo20p in sporulating cells. Analysis of chimeric Sec9p/Spo20p molecules indicates that regions in both the SNAP-25 domain and the unique N terminus of Spo20p are required for activity during sporulation. Additionally, the N terminus of Spo20p is inhibitory in vegetative cells. Deletion studies indicate that activation and inhibition are separable functions of the Spo20p N terminus. Our results reveal an additional layer of regulation of the SNARE complex, which is necessary only in sporulating cells.
35
Gilles, Tijs, Kath Phelps, John P. Clarkson und Roy Kennedy. „Development of MILIONCAST, an Improved Model for Predicting Downy Mildew Sporulation on Onions“. Plant Disease 88, Nr. 7 (Juli 2004): 695–702. http://dx.doi.org/10.1094/pdis.2004.88.7.695.
Annotation:
The effects of temperature and relative humidity on Peronospora destructor sporulation on onion (Allium cepa) leaves were studied under controlled environmental conditions. Sporangia were produced most rapidly at 8 to 12°C after 5 h of high humidity during dark periods. The greatest number of sporangia was produced at 100% relative humidity (RH), and sporulation decreased to almost nil when humidity decreased to 93% RH. A model, named MILIONCAST (an acronym for MILdew on onION foreCAST), was developed based on the data from these controlled environment studies to predict the rate of sporulation in relation to temperature and relative humidity. The accuracy of prediction of sporulation was evaluated by comparing predictions with observations of sporulation on infected plants in pots outdoors. The accuracy of MILIONCAST was compared with the accuracy of existing models based on DOWNCAST. MILIONCAST gave more correct predictions of sporulation than the DOWNCAST models and a random model. All models based on DOWNCAST were more accurate than the random model when compared on the basis of all predictions (including positive and negative predictions), but they gave fewer correct predictions of sporulation than the random model. De Visser's DOWNCAST and ONIMIL improved their accuracy of prediction of sporulation events when the threshold humidity for sporulation was reduced to 92% RH. The temporal pattern of predicted sporulation by MILIONCAST generally corresponded well to the pattern of sporulation observed on the outdoor potted plants at Wellesbourne, UK.
36
Singh, Simranjit, Upasana Rani, U. S. Tiwana, Devinder Pal Singh und Asmita Sirari. „Investigation of optimum conditions for the growth of Fusarium solani EGY1 causing root rot of guar (Cyamopsis tetragonoloba L.)“. Journal of Applied and Natural Science 9, Nr. 4 (01.12.2017): 2249–54. http://dx.doi.org/10.31018/jans.v9i4.1519.
Annotation:
Guar gum (Galactomannan) is extracted from Guar (Cluster bean), which is extensively used in petroleum, food and pharmaceutical industry. Root rot of guaris caused by Fusarium solani EGY1 under Punjab, having sub-tropical climatic conditions. This study was undertaken to evaluate different culture media, grain substrates (sorghum, maize, cowpea, guar and pearl millet), temperatures (20, 25, 30, 35oC), pH levels (5.0, 6.0, 7.0, 8.0), light and darkness for the identification of optimum conditions for the growth and sporulation of the fungus. Czapek’s dox media was found to be best for growth (84.65 mm) and sporulation (1.8 x 104microconidia and 3.0 x 104 macro conidia) of fungus. For mass multiplication of the fungus, sorghum grains proved to be the best substrate. The fungus showed maximum radial growth at temperature of 25oC (84.36 mm) and pH of 6.0 (84.43 mm) whereas sporulation was highest at 30oC (2.0 x 104 microconidia and 3.2 x 104 macroconidia) and pH of 8.0 (1.8 x 104 microconidia and 3.1 x 104 macroconidia) respectively. Continuous light favoured radial growth (84.62 mm) whereas sporulation (1.8 x 104 microconidia and 3.1 x 104 macroconidia) was favoured by darkness.
37
Aravind, K., T. Kiran Babu, B. Rajeswari und S. N. C. V. L. Pushpavalli. „Precise Methods for Single Spore Isolation and Controlled Sporulation in Magnaporthe oryzae Isolates“. International Journal of Environment and Climate Change 13, Nr. 10 (06.09.2023): 2411–18. http://dx.doi.org/10.9734/ijecc/2023/v13i102906.
Annotation:
The present investigation focuses on enhancing the understanding of Magnaporthe oryzae, the causal agent of rice blast disease, by developing simple and cost-efficient protocols for single spore isolation and controlled sporulation with minimal equipment. In pursuit of this objective, various natural hosts were evaluated for their sporulation potential at different time intervals. The results revealed the significant differences in sporulation of M. oryzae among different hosts at different time intervals, showing higher sporulation at 14 DAI compared to 10 DAI. Notably, rice leaves from TN-1 and HR-12 cultivars exhibited robust sporulation at 14 DAI under a 14-hr light + 8 hr dark conditions. Validating these findings, twelve isolates from various locations in Telangana State consistently confirmed that rice leaves from cultivar TN-1 supporting the highest mean sporulation rate, followed by the HR-12 cultivar. The implications of these findings extend to aiding researchers and rice breeders in comprehending disease dynamics, formulating effective control strategies, and developing rice cultivars resilient against rice blast.
38
Saha, Aniruddha, Chandrani Choudhuri und Dipanwita Saha. „Influence of culture media and environmental factors on mycelial growth and sporulation of Alternaria alternata (Fr.) Keissler causing leaf blight disease of niger (Guizotia abyssinica (L.f.) cass)“. NBU Journal of Plant Sciences 9, Nr. 1 (2015): 87–93. http://dx.doi.org/10.55734/nbujps.2015.v09i01.011.
Annotation:
Alternaria altermata is isolated from naturally infected niger leaf for their morphological characteristics, mycelia growth and sporulation, spore germination in different culture media and environmental conditions. RMA was best for both growth and sporulation. Excellent sporulation was observed ion PCA. PDB supported best growth among the liquid media tested. Highest mycelia dry weight was recorded at 28°C and pH 6.5. Among several carbon sources tested, Mannitol showed optimum growth and sporulation while peptone produced maximum growth among the tested organic nitrogen sources. The present study will help to maintain the fungus in the laboratory condition for preparation of inoculums for different studies related to the control measures of the pathogen.
39
Boyko, O. O., L. I. Shendryk, V. S. Rudyk, I. A. Volovyk, I. A. Biben und V. V. Brygadyrenko. „Influence of temperature on sporulation of Eimeria arloingi and Eimeria perforans oocysts“. Regulatory Mechanisms in Biosystems 12, Nr. 2 (03.05.2021): 369–73. http://dx.doi.org/10.15421/022150.
Annotation:
Eimeriosis of farm animals is one of the most widespread parasitic diseases in the world. In the conditions of the steppe zone of Ukraine Eimeria perforans is more common in rabbits and E. arloingi in sheep and goats. Study of factors which influence the development of these protists on the soil surface is one of the major challenges for veterinarians working for large livestock companies and fighting against eimeriosis. Environmental temperature is able to change the speed of sporulation of oocysts Eimeria. Five values of temperature (15, 20, 25, 30, and 35 °C) were used in a laboratory experiment in vitro. At 15 °C, the process of sporulation of E. arloingi and E. perforans in 100% of cases ended on the eighth day. With increase in temperature to 35 °C, the duration of sporulation decreased to three days. When the temperature was 30 °C the completion of sporulation was observed in more than 50% of the oocysts of E. arloingi on the second day, and for E. perforans on the third day. High-speed sporulation at elevated temperatures under conditions of global warming can result in the increasing spread of eimeriosis among wild and domestic animals.
40
Matha, Amber R., Xiaofeng Xie und Xiaorong Lin. „Ergosterol Is Critical for Sporogenesis in Cryptococcus neoformans“. Journal of Fungi 10, Nr. 2 (26.01.2024): 106. http://dx.doi.org/10.3390/jof10020106.
Annotation:
Microbes, both bacteria and fungi, produce spores to survive stressful conditions. Spores produced by the environmental fungal pathogen Cryptococcus neoformans serve as both surviving and infectious propagules. Because of their importance in disease transmission and pathogenesis, factors necessary for cryptococcal spore germination are being actively investigated. However, little is known about nutrients critical for sporogenesis in this pathogen. Here, we found that ergosterol, the main sterol in fungal membranes, is enriched in spores relative to yeasts and hyphae. In C. neoformans, the ergosterol biosynthesis pathway (EBP) is upregulated by the transcription factor Sre1 in response to conditions that demand elevated ergosterol biosynthesis. Although the deletion of SRE1 enhances the production of mating hyphae, the sre1Δ strain is deficient at producing spores even when crossed with a wild-type partner. We found that the defect of the sre1Δ strain is specific to sporogenesis, not meiosis or basidium maturation preceding sporulation. Consistent with the idea that sporulation demands heightened ergosterol biosynthesis, EBP mutants are also defective in sporulation. We discovered that the overexpression of some EBP genes can largely rescue the sporulation defect of the sre1Δ strain. Collectively, we demonstrate that ergosterol is a critical component in cryptococcal preparation for sporulation.
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Gehin, A., E. Gelhaye, G. Raval und H. Petitdemange. „Clostridium cellulolyticum Viability and Sporulation under Cellobiose Starvation Conditions.“ Applied and environmental microbiology 61, Nr. 3 (1995): 868–71. http://dx.doi.org/10.1128/aem.61.3.868-871.1995.
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Campbell, M. A., R. W. Medd und J. B. Brown. „Optimizing conditions for growth and sporulation of Pyrenophora semeniperda“. Plant Pathology 52, Nr. 4 (August 2003): 448–54. http://dx.doi.org/10.1046/j.1365-3059.2003.00872.x.
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Chevanet, Catherine, Françoise Besson und Georges Michel. „Effect of various growth conditions on spore formation and bacillomycin L production in Bacillus subtilis“. Canadian Journal of Microbiology 32, Nr. 3 (01.03.1986): 254–58. http://dx.doi.org/10.1139/m86-050.
Annotation:
Bacillomycin L is produced by Bacillus subtilis NCIB 8872 in the stationary phase; it is excreted into the culture medium, without prior accumulation in the bacterial cells. The production of bacillomycin L is largely dependent on the composition of the culture medium. The action of specific inhibitors of sporulation, netropsin and diethyl malonate, on antibiotic synthesis is dependent on the composition of the culture medium. Although they occurred at the same time, there appears to be no direct correlation between sporulation and antibiotic synthesis.
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Zimowska, Beata. „Effect of cultivation conditions on Seimatosporium hypericinum growth and form morfological structures“. Acta Agrobotanica 55, Nr. 1 (2013): 401–10. http://dx.doi.org/10.5586/aa.2002.038.
Annotation:
The present study deals with effects of the air temperature, and the type of medium on the growth and form morfological structures of six <i>Seimatosporium hypericinum</i> isolates tested. St Jonh's Wort extract agar, St Jonh's Wort plant agar and PDA, oatmeal agar has been recognized as most useful for growth and sporulation of <i>S.hypericinum</i>. Mineral agar, appeared the least useful for growth and form acervuli and conidia. <i>S.hypericinum </i>can develop in a wide range of temperature, but the optimum one for the growth and sporulation of the fungus vary between 20°C and 28°C.
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Stier, Philipp, und Ulrich Kulozik. „Effect of Sporulation Conditions Following Submerged Cultivation on the Resistance of Bacillus atrophaeus Spores against Inactivation by H2O2“. Molecules 25, Nr. 13 (30.06.2020): 2985. http://dx.doi.org/10.3390/molecules25132985.
Annotation:
The resistance formation of spores in general and of Bacillus atrophaeus in particular has long been the focus of science in the bio-defense, pharmaceutical and food industries. In the food industry, it is used as a biological indicator (BI) for the evaluation of the inactivation effects of hydrogen peroxide in processing and end packaging lines’ sterilization. Defined BI resistances are critical to avoid false positive and negative tests, which are salient problems due to the variable resistance of currently available commercial BIs. Although spores for use as BIs have been produced for years, little is known about the influence of sporulation conditions on the resistance as a potential source of random variability. This study therefore examines the dependence of spore resistance on the temperature, pH and partial oxygen saturation during submerged production in a bioreactor. For this purpose, spores were produced under different sporulation conditions and their resistance, defined by the D-value, was determined using a count reduction test in tempered 35% liquid hydrogen peroxide. The statistical analysis of the test results shows a quadratic dependence of the resistance on the pH, with the highest D-values at neutral pH. The sporulation temperature has a linear influence on the resistance. The higher the temperature, the higher the D-value. However, these factors interact with each other, which means that the temperature only influences the resistance when the pH is within a certain range. The oxygen partial pressure during sporulation has no significant influence. Based on the data obtained, a model could be developed enabling the resistance of BIs to be calculated, predicted and standardized depending on the sporulation conditions. BI manufacturers could thus produce BIs with defined resistances for the validation of sterilization effects in aseptic packaging/filling lines for the reliable manufacture of shelf-stable and safe food products.
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Diallo, Mamou, Servé W. M. Kengen und Ana M. López-Contreras. „Sporulation in solventogenic and acetogenic clostridia“. Applied Microbiology and Biotechnology 105, Nr. 9 (26.04.2021): 3533–57. http://dx.doi.org/10.1007/s00253-021-11289-9.
Annotation:
AbstractThe Clostridium genus harbors compelling organisms for biotechnological production processes; while acetogenic clostridia can fix C1-compounds to produce acetate and ethanol, solventogenic clostridia can utilize a wide range of carbon sources to produce commercially valuable carboxylic acids, alcohols, and ketones by fermentation. Despite their potential, the conversion by these bacteria of carbohydrates or C1 compounds to alcohols is not cost-effective enough to result in economically viable processes. Engineering solventogenic clostridia by impairing sporulation is one of the investigated approaches to improve solvent productivity. Sporulation is a cell differentiation process triggered in bacteria in response to exposure to environmental stressors. The generated spores are metabolically inactive but resistant to harsh conditions (UV, chemicals, heat, oxygen). In Firmicutes, sporulation has been mainly studied in bacilli and pathogenic clostridia, and our knowledge of sporulation in solvent-producing or acetogenic clostridia is limited. Still, sporulation is an integral part of the cellular physiology of clostridia; thus, understanding the regulation of sporulation and its connection to solvent production may give clues to improve the performance of solventogenic clostridia. This review aims to provide an overview of the triggers, characteristics, and regulatory mechanism of sporulation in solventogenic clostridia. Those are further compared to the current knowledge on sporulation in the industrially relevant acetogenic clostridia. Finally, the potential applications of spores for process improvement are discussed.Key Points• The regulatory network governing sporulation initiation varies in solventogenic clostridia.• Media composition and cell density are the main triggers of sporulation.• Spores can be used to improve the fermentation process.
47
Percival-Smith, A., und J. Segall. „Characterization and mutational analysis of a cluster of three genes expressed preferentially during sporulation of Saccharomyces cerevisiae“. Molecular and Cellular Biology 6, Nr. 7 (Juli 1986): 2443–51. http://dx.doi.org/10.1128/mcb.6.7.2443-2451.1986.
Annotation:
A differential hybridization screen of a genomic yeast DNA library previously identified 14 genes of Saccharomyces cerevisiae that are expressed preferentially during sporulation. Three of these sporulation-specific genes, SPS1, SPS2, and SPS3, have been shown to be closely linked. A mutational analysis has demonstrated that expression of the SPS1 gene, but not the SPS2 gene, is essential for the completion of sporulation. A diploid MATa/MAT alpha strain homozygous for a disruption of the SPS1 gene failed to form asci when subjected to sporulation conditions. The 3' end of the transcript encoded by the SPS1 gene was found to map only 185 base pairs from the 5' end of the SPS2 gene. The SPS1-SPS2 intergenic region was shown to contain all of the regulatory sequences necessary for the sporulation-specific activation of the SPS2 gene as assessed by expression of a translational SPS2-lacZ fusion gene present on a replicating, centromere-containing plasmid. The fusion gene was found to be expressed at the same time during sporulation as the chromosomal wild-type SPS2 gene.
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Percival-Smith, A., und J. Segall. „Characterization and mutational analysis of a cluster of three genes expressed preferentially during sporulation of Saccharomyces cerevisiae.“ Molecular and Cellular Biology 6, Nr. 7 (Juli 1986): 2443–51. http://dx.doi.org/10.1128/mcb.6.7.2443.
Annotation:
A differential hybridization screen of a genomic yeast DNA library previously identified 14 genes of Saccharomyces cerevisiae that are expressed preferentially during sporulation. Three of these sporulation-specific genes, SPS1, SPS2, and SPS3, have been shown to be closely linked. A mutational analysis has demonstrated that expression of the SPS1 gene, but not the SPS2 gene, is essential for the completion of sporulation. A diploid MATa/MAT alpha strain homozygous for a disruption of the SPS1 gene failed to form asci when subjected to sporulation conditions. The 3' end of the transcript encoded by the SPS1 gene was found to map only 185 base pairs from the 5' end of the SPS2 gene. The SPS1-SPS2 intergenic region was shown to contain all of the regulatory sequences necessary for the sporulation-specific activation of the SPS2 gene as assessed by expression of a translational SPS2-lacZ fusion gene present on a replicating, centromere-containing plasmid. The fusion gene was found to be expressed at the same time during sporulation as the chromosomal wild-type SPS2 gene.
49
Weaver, M., R. Hoagland, C. Boyette und R. Zablotowicz. „Macrocyclic trichothecene production and sporulation by a biological control strain of Myrothecium verrucaria is regulated by cultural conditions“. World Mycotoxin Journal 2, Nr. 1 (01.02.2009): 35–43. http://dx.doi.org/10.3920/wmj2008.1026.
Annotation:
Myrothecium verrucaria is a pathogen of several invasive weed species, including kudzu, and is currently being evaluated for use as a bioherbicide. However, the fungus also produces macrocyclic trichothecene mycotoxins. The safety of this biological control agent during production and handling would be improved if an inoculum could be produced without concomitant accumulation of macrocyclic trichothecenes. Sporulation and trichothecene production by M. verrucaria was evaluated on standard potato dextrose agar (PDA) and a series of complex and defined media. Sporulation on PDA and on agar media with nitrogen as ammonium nitrate or potassium nitrate was more than ten-fold greater then sporulation on the medium with ammonium sulphate as the nitrogen source. Accumulation of macrocyclic trichothecenes was strongly affected by the media composition, with higher levels often associated with higher carbon content in the media. Overall, incubation in continuous darkness resulted in higher macrocyclic trichothecene concentrations. Results support the hypothesis that accumulation of macrocyclic trichothecenes by this fungus can be altered by manipulating carbon and nitrogen sources. Furthermore, the biosynthesis of these mycotoxins may be independent of sporulation, demonstrating that the bioherbicide can be readily produced on solid substrates while simultaneously yielding conidia that are less threatening to worker safety. A more detailed implementation of the concepts demonstrated in this study will facilitate the safe and economical production of this bioherbicide.
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Novella, Isabel S., Covadonga Barbés und Jesús Sánchez. „Sporulation of Streptomyces antibioticus ETHZ 7451 in submerged culture“. Canadian Journal of Microbiology 38, Nr. 8 (01.08.1992): 769–73. http://dx.doi.org/10.1139/m92-125.
Annotation:
Streptomyces antibioticus ETHZ 7451 formed spores in cultures grown in a liquid medium from either a spore or a mycelium inoculum. The spores formed were similar to those formed on surface-grown cultures, except for reduced heat resistance. Both types of spores were sensitive to lysozyme, which is unusual for Streptomyces spores. Glucose and other carbon sources, which promoted different growth rates, did not affect sporulation efficiency. Nitrogen sources, such as casamino acids, that allowed high growth rates suppressed the sporulation. A remarkable repression was also observed in media with some nitrogen sources that promoted noticeably lower growth rates. In permissive media, with nitrogen sources that permitted relatively high growth rates, sporulation was conditioned to the consumption of ammonium in the medium, but not to that of other nitrogen sources, such as asparagine. Phosphate did not show a repressive effect on sporulation in the assayed conditions. Key words: Streptomyces antibioticus, sporulation.