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Gibson DM, Myers JE. Gender and Infertility: A Relational Approach to Counseling Women. JOURNAL OF COUNSELING AND DEVELOPMENT 2011. [DOI: 10.1002/j.1556-6676.2000.tb01923.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Gibson DM, Krasnoff SB, Biazzo J, Milbrath L. Phytotoxicity of antofine from invasive swallow-worts. J Chem Ecol 2011; 37:871-9. [PMID: 21739223 DOI: 10.1007/s10886-011-9994-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 06/26/2011] [Accepted: 06/28/2011] [Indexed: 11/27/2022]
Abstract
Pale swallow-wort (Vincetoxicum rossicum) and black swallow-wort (V. nigrum) are two emerging invasive plant species in the northeastern United States and southeastern Canada that have shown rapid population expansion over the past 20 years. Using bioassay-guided fractionation, the known phytochemical phenanthroindolizidine alkaloid, (-)-antofine, was identified as a potent phytotoxin in roots, leaves, and seeds of both swallow-wort species. In seedling bioassays, (-)-antofine, at μM concentrations, resulted in greatly reduced root growth of Asclepias tuberosa, A. syriaca, and Apocynum cannabinum, three related, native plant species typically found in habitats where large stands of swallow-wort are present. In contrast, antofine exhibited moderate activity against lettuce, and it had little effect on germination and root growth of either black or pale swallow-wort. In disk diffusion assays, antifungal activity was observed at 10 μg and 100 μg, while antibacterial activity was seen only at the higher level. Although both swallow-wort species display multiple growth and reproductive characteristics that may play an important role in their invasiveness, the presence of the highly bioactive phytochemical (-)-antofine in root and seed tissues indicates a potential allelopathic role in swallow-worts' invasiveness.
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Gibson DM, King BC, Hayes ML, Bergstrom GC. Plant pathogens as a source of diverse enzymes for lignocellulose digestion. Curr Opin Microbiol 2011; 14:264-70. [DOI: 10.1016/j.mib.2011.04.002] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Accepted: 04/07/2011] [Indexed: 01/09/2023]
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King BC, Waxman KD, Nenni NV, Walker LP, Bergstrom GC, Gibson DM. Arsenal of plant cell wall degrading enzymes reflects host preference among plant pathogenic fungi. BIOTECHNOLOGY FOR BIOFUELS 2011; 4:4. [PMID: 21324176 PMCID: PMC3051899 DOI: 10.1186/1754-6834-4-4] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 02/16/2011] [Indexed: 05/06/2023]
Abstract
BACKGROUND The discovery and development of novel plant cell wall degrading enzymes is a key step towards more efficient depolymerization of polysaccharides to fermentable sugars for the production of liquid transportation biofuels and other bioproducts. The industrial fungus Trichoderma reesei is known to be highly cellulolytic and is a major industrial microbial source for commercial cellulases, xylanases and other cell wall degrading enzymes. However, enzyme-prospecting research continues to identify opportunities to enhance the activity of T. reesei enzyme preparations by supplementing with enzymatic diversity from other microbes. The goal of this study was to evaluate the enzymatic potential of a broad range of plant pathogenic and non-pathogenic fungi for their ability to degrade plant biomass and isolated polysaccharides. RESULTS Large-scale screening identified a range of hydrolytic activities among 348 unique isolates representing 156 species of plant pathogenic and non-pathogenic fungi. Hierarchical clustering was used to identify groups of species with similar hydrolytic profiles. Among moderately and highly active species, plant pathogenic species were found to be more active than non-pathogens on six of eight substrates tested, with no significant difference seen on the other two substrates. Among the pathogenic fungi, greater hydrolysis was seen when they were tested on biomass and hemicellulose derived from their host plants (commelinoid monocot or dicot). Although T. reesei has a hydrolytic profile that is highly active on cellulose and pretreated biomass, it was less active than some natural isolates of fungi when tested on xylans and untreated biomass. CONCLUSIONS Several highly active isolates of plant pathogenic fungi were identified, particularly when tested on xylans and untreated biomass. There were statistically significant preferences for biomass type reflecting the monocot or dicot host preference of the pathogen tested. These highly active fungi are promising targets for identification and characterization of novel cell wall degrading enzymes for industrial applications.
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Gibson DM, Shine WE. Uridine diphosphate glucose breakdown is mediated by a unique enzyme activated by fructose 2,6-bisphosphate in Solanum tuberosum. Proc Natl Acad Sci U S A 2010; 80:2491-4. [PMID: 16593304 PMCID: PMC393851 DOI: 10.1073/pnas.80.9.2491] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the presence of inorganic phosphate, uridine 5'-diphosphate glucose (UDPG) is specifically hydrolyzed to glucose 1-phosphate and UDP by a unique enzyme, UDPG phosphorylase. The activity of the enzyme was maximally stimulated by fructose 2,6-bisphosphate, a regulatory metabolite recently discovered in both plants and animals, and by 2-phosphoglyceric acid. At 1 muM, fructose 2,6-bisphosphate stimulated UDPG phosphorolysis 10-fold, whereas 2-phosphoglyceric acid was required at higher concentrations (100 muM) to produce a similar effect. Fructose 2,6-bisphosphate appears to increase the affinity of the enzyme for inorganic phosphate, with a change in K(m) from 1.6 mM to 0.3 mM. The results suggest that fructose 2,6-bisphosphate participates in the regulation of other pathways of carbohydrate metabolism in addition to playing its recognized role in glycolysis and gluconeogenesis.
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Bernal ME, Gibson DM, Williams DE, Pesses DI. A device for recording automatic audio tape recording. J Appl Behav Anal 2010; 4:151-6. [PMID: 16795287 PMCID: PMC1310682 DOI: 10.1901/jaba.1971.4-151] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adaptation of a commercially available timer for use as a means of operating an audio tape recorder several times during the day is described. Data on a mother's rates of commanding her children were collected via both physically present observer and recorder methods in order to compare the usefulness of the recordings with direct observation. There was a high positive relationship between observer-recorder command rates, with the observer rates being consistently higher, when data were collected via both methods simultaneously as well as at different points in time.
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Gibson DM, Broom DH, Duncan-Jones P. Access to dental care amongst the aged. COMMUNITY HEALTH STUDIES 2010; 8:62-74. [PMID: 6713822 DOI: 10.1111/j.1753-6405.1984.tb00425.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Donzelli BGG, Krasnoff SB, Churchill ACL, Vandenberg JD, Gibson DM. Identification of a hybrid PKS-NRPS required for the biosynthesis of NG-391 in Metarhizium robertsii. Curr Genet 2010; 56:151-62. [PMID: 20355253 DOI: 10.1007/s00294-010-0288-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The fungal entomopathogen Metarhizium robertsii (formerly known as M. anisopliae var. anisopliae) is a prolific producer of secondary metabolites of which very little is known at the genetic level. To establish the genetic bases for the biosynthesis of the mutagenic compound NG- 391, we identified a 19,818 kb genomic region harboring the predicted hybrid polyketide synthase-nonribosomal peptide synthetase NGS1, plus five additional ORFs. NGS1 knockouts generated by Agrobacterium-mediated transformation failed to produce detectable levels of NG-391, indicating the involvement of this locus in its biosynthesis. NGS1 deletion mutants had no significant changes in virulence levels against larvae of Spodoptera exigua and in resistance to hydrogen peroxide-generated oxidative stress compared to the wild-type strain. All 6 ORFs were expressed in medium supporting production of NG-391, and NGS1 was expressed during the interaction with the S. exigua host. The use of an NGS1 promoter-GFP reporter fusion showed that during in vitro growth in still broth cultures, NGS1 expression is restricted to the early exponential phase and is affected by M. robertsii cell density.
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Molnár I, Gibson DM, Krasnoff SB. Secondary metabolites from entomopathogenic Hypocrealean fungi. Nat Prod Rep 2010; 27:1241-75. [DOI: 10.1039/c001459c] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Johnson EG, Krasnoff SB, Bignell DRD, Chung WC, Tao T, Parry RJ, Loria R, Gibson DM. 4-Nitrotryptophan is a substrate for the non-ribosomal peptide synthetase TxtB in the thaxtomin A biosynthetic pathway. Mol Microbiol 2009; 73:409-18. [DOI: 10.1111/j.1365-2958.2009.06780.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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King BC, Donnelly MK, Bergstrom GC, Walker LP, Gibson DM. An optimized microplate assay system for quantitative evaluation of plant cell wall-degrading enzyme activity of fungal culture extracts. Biotechnol Bioeng 2009; 102:1033-44. [PMID: 18973283 DOI: 10.1002/bit.22151] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Developing enzyme cocktails for cellulosic biomass hydrolysis complementary to current cellulase systems is a critical step needed for economically viable biofuels production. Recent genomic analysis indicates that some plant pathogenic fungi are likely a largely untapped resource in which to prospect for novel hydrolytic enzymes for biomass conversion. In order to develop high throughput screening assays for enzyme bioprospecting, a standardized microplate assay was developed for rapid analysis of polysaccharide hydrolysis by fungal extracts, incorporating biomass substrates. Fungi were grown for 10 days on cellulose- or switchgrass-containing media to produce enzyme extracts for analysis. Reducing sugar released from filter paper, Avicel, corn stalk, switchgrass, carboxymethylcellulose, and arabinoxylan was quantified using a miniaturized colorimetric assay based on 3,5-dinitrosalicylic acid. Significant interactions were identified among fungal species, growth media composition, assay substrate, and temperature. Within a small sampling of plant pathogenic fungi, some extracts had crude activities comparable to or greater than T. reesei, particularly when assayed at lower temperatures and on biomass substrates. This microplate assay system should prove useful for high-throughput bioprospecting for new sources of novel enzymes for biofuel production.
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Kim BJ, Gibson DM, Shuler ML. Relationship of Viability and Apoptosis to Taxol Production in Taxus sp. Suspension Cultures Elicited with Methyl Jasmonate. Biotechnol Prog 2008; 21:700-7. [PMID: 15932245 DOI: 10.1021/bp050016z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Taxus cuspidata P991 in plant cell suspension culture is capable of producing the important anticancer agent Taxol (paclitaxel) and related taxanes. High-level production is obtained by elicitation with methyl jasmonate, but successful elicitation leads to loss of cell viability that cannot be recovered by subculture. Here, we test whether the loss of viability is due to a direct effect of methyl jasmonate. Upon subculture, the reduced viability continued in methyl jasmonate elicited cultures, but not in nonelicited control cultures. The growth reduction in elicited T. cuspidata P991 suspension cultures was evaluated by viability reduction measurements using phenosafranin and fluorescein diacetate. The viability reduction does not appear to be related to apoptosis based on DNA laddering analysis because it occurred very late (at day 35) in the culture period. DNA laddering was also found only after day 28 in T. canadensis C93AD (a Taxol-producing cell line) elicited with methyl jasmonate, implying that apoptosis is not the major death mechanism after elicitation. As compared to Taxol-producing cell lines, the viability of a nonproducing cell line, T. canadensis CO93D, was not severely affected by methyl jasmonate, indicating that methyl jasmonate itself is not the primary factor for viability reduction. Based on Northern analysis of taxadiene synthase mRNA from both elicited and nonelicited T. cuspidata P991, methyl jasmonate directly induces the production of this enzyme, which is the first committed step in the biosynthetic pathway for Taxol. As a result, both viability reduction and growth reduction appear related to a high production level of Taxol (and related taxanes) upon methyl jasmonate elicitation, rather than to the direct effect of methyl jasmonate.
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Johnson EG, Sparks JP, Dzikovski B, Crane BR, Gibson DM, Loria R. Plant-pathogenic Streptomyces species produce nitric oxide synthase-derived nitric oxide in response to host signals. ACTA ACUST UNITED AC 2008; 15:43-50. [PMID: 18215772 DOI: 10.1016/j.chembiol.2007.11.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 10/22/2007] [Accepted: 11/26/2007] [Indexed: 12/27/2022]
Abstract
Nitric oxide (NO) is a potent intercellular signal for defense, development, and metabolism in animals and plants. In mammals, highly regulated nitric oxide synthases (NOSs) generate NO. NOS homologs exist in some prokaryotes, but direct evidence for NO production by these proteins has been lacking. Here, we demonstrate that a NOS in plant-pathogenic Streptomyces species produces diffusible NO. NOS-dependent NO production increased in response to cellobiose, a plant cell wall component, and occurred at the host-pathogen interface, demonstrating induction by host signals. These data document in vivo production of NO by prokaryotic NOSs and implicate pathogen-derived NO in host-pathogen interactions. NO may serve as a signaling molecule in other NOS-containing bacteria, including the medically and environmentally important organisms Bacillus anthracis, Staphylococcus aureus, and Deinococcus radiodurans.
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Pryor SW, Gibson DM, Hay AG, Gossett JM, Walker LP. Optimization of spore and antifungal lipopeptide production during the solid-state fermentation of Bacillus subtilis. Appl Biochem Biotechnol 2007; 143:63-79. [PMID: 18025597 DOI: 10.1007/s12010-007-0036-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 11/30/1999] [Accepted: 03/09/2007] [Indexed: 11/29/2022]
Abstract
Bacillus subtilis strain TrigoCor 1448 was grown on wheat middlings in 0.5-l solid-state fermentation (SSF) bioreactors for the production of an antifungal biological control agent. Total antifungal activity was quantified using a 96-well microplate bioassay against the plant pathogen Fusarium oxysporum f. sp. melonis. The experimental design for process optimization consisted of a 2(6-1) fractional factorial design followed by a central composite face-centered design. Initial SSF parameters included in the optimization were aeration, fermentation length, pH buffering, peptone addition, nitrate addition, and incubator temperature. Central composite face-centered design parameters included incubator temperature, aeration rate, and initial moisture content (MC). Optimized fermentation conditions were determined with response surface models fitted for both spore concentration and activity of biological control product extracts. Models showed that activity measurements and spore production were most sensitive to substrate MC with highest levels of each response variable occurring at maximum moisture levels. Whereas maximum antifungal activity was seen in a limited area of the design space, spore production was fairly robust with near maximum levels occurring over a wider range of fermentation conditions. Optimization resulted in a 55% increase in inhibition and a 40% increase in spore production over nonoptimized conditions.
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Krasnoff SB, Keresztes I, Gillilan RE, Szebenyi DME, Donzelli BGG, Churchill ACL, Gibson DM. Serinocyclins A and B, cyclic heptapeptides from Metarhizium anisopliae. JOURNAL OF NATURAL PRODUCTS 2007; 70:1919-1924. [PMID: 18044842 DOI: 10.1021/np070407i] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two new cyclic heptapeptides, serinocyclins A (1) and B (2), were isolated from conidia of the entomopathogenic fungus Metarhizium anisopliae. Structures were elucidated by a combination of mass spectrometric, NMR, and X-ray diffraction techniques. Serinocyclin A (1) contains three serine units, a hydroxyproline (Hyp), a beta-alanine (beta-Ala), and two uncommon nonproteinogenic amino acids, 1-aminocyclopropane-1-carboxylic acid (Acc) and gamma-hydroxylysine (HyLys). The peptide sequence established for 1 by NMR is cyclo-(Acc-Hyp-Ser1-HyLys-beta-Ala-Ser2-Ser3). Serinocyclin B (2) has Lys in place of the HyLys unit found in 1. Chiral amino acid analysis indicated the presence in both compounds of one (2 S,4 R)-Hyp, two L-Ser, and one D-Ser residue. A Lys found in the hydrolyzate of 2 was established as D-configured. A crystal structure of 1 established the position of the D-Ser (Ser2) and the absolute configuration of the HyLys unit (2 R,4 S). The absence of methyl groups is unusual among fungal peptides and, along with the charged lysyl side chain and multiple hydroxyl groups, contributes to the polar nature of the compounds. Serinocyclin A produced a sublethal locomotory defect in mosquito larvae at an EC 50 of 59 ppm.
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Pryor SW, Siebert KJ, Gibson DM, Gossett JM, Walker LP. Modeling production of antifungal compounds and their role in biocontrol product inhibitory activity. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:9530-9536. [PMID: 17949051 DOI: 10.1021/jf0719252] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Partial least squares (PLS) regression modeling was used to relate the antifungal activity of Bacillus subtilis solid-state fermentation extracts to the individual high-performance liquid chromatography (HPLC) peaks from those extracts. A model was developed that predicted bioassay inhibition based on the extract HPLC profile (R(2) = 0.99). Concentrations of the members of the antifungal lipopeptide families iturin A and fengycin were found to correlate positively with extract inhibition, but a peak with unidentified chemical composition (designated as peak 48) showed the strongest correlation with extract inhibition. HPLC data were used to construct models for the production of iturin A, fengycin, and peak 48 as a function of the substrate moisture content, incubator temperature, and aeration rate in the solid-state bioreactors. Maximum production of all compounds occurred at the highest moisture content (1.7 g/g dry basis) and lowest incubator temperature (19 degrees C) tested. Optimal aeration rates for the production of the two known lipopeptides and peak 48 were 0.1 and 1.5 L/min, respectively.
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Joshi MV, Bignell DRD, Johnson EG, Sparks JP, Gibson DM, Loria R. The AraC/XylS regulator TxtR modulates thaxtomin biosynthesis and virulence in Streptomyces scabies. Mol Microbiol 2007; 66:633-42. [PMID: 17919290 DOI: 10.1111/j.1365-2958.2007.05942.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Streptomyces scabies is the best studied of those streptomycetes that cause an economically important disease known as potato scab. The phytotoxin thaxtomin is made exclusively by these pathogens and is required for virulence. Here we describe regulation of thaxtomin biosynthesis by TxtR, a member of the AraC/XylS family of transcriptional regulators. The txtR gene is imbedded in the thaxtomin biosynthetic pathway and is located on a conserved pathogenicity island in S. scabies, S. turgidiscabies and S. acidiscabies. Thaxtomin biosynthesis was abolished and virulence was almost eliminated in the txtR deletion mutant of S. scabies 87.22. Accumulation of thaxtomin biosynthetic gene (txtA, txtB, txtC, nos) transcripts was reduced compared with the wild-type S. scabies 87.22. NOS-dependent nitric oxide production by S. scabies was also reduced in the mutant. The TxtR protein bound cellobiose, an inducer of thaxtomin production, and transcription of txtR and thaxtomin biosynthetic genes was upregulated in response to cellobiose. TxtR is the first example of an AraC/XylS family protein regulated by cellobiose. Together, these data suggest that cellobiose, the smallest oligomer of cellulose, may signal the availability of expanding plant tissue, which is the site of action of thaxtomin.
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Oide S, Krasnoff SB, Gibson DM, Turgeon BG. Intracellular siderophores are essential for ascomycete sexual development in heterothallic Cochliobolus heterostrophus and homothallic Gibberella zeae. EUKARYOTIC CELL 2007; 6:1339-53. [PMID: 17601875 PMCID: PMC1951124 DOI: 10.1128/ec.00111-07] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Connections between fungal development and secondary metabolism have been reported previously, but as yet, no comprehensive analysis of a family of secondary metabolites and their possible role in fungal development has been reported. In the present study, mutant strains of the heterothallic ascomycete Cochliobolus heterostrophus, each lacking one of 12 genes (NPS1 to NPS12) encoding a nonribosomal peptide synthetase (NRPS), were examined for a role in sexual development. One type of strain (Delta nps2) was defective in ascus/ascospore development in homozygous Delta nps2 crosses. Homozygous crosses of the remaining 11 Delta nps strains showed wild-type (WT) fertility. Phylogenetic, expression, and biochemical analyses demonstrated that the NRPS encoded by NPS2 is responsible for the biosynthesis of ferricrocin, the intracellular siderophore of C. heterostrophus. Functional conservation of NPS2 in both heterothallic C. heterostrophus and the unrelated homothallic ascomycete Gibberella zeae was demonstrated. G. zeae Delta nps2 strains are concomitantly defective in intracellular siderophore (ferricrocin) biosynthesis and sexual development. Exogenous application of iron partially restored fertility to C. heterostrophus and G. zeae Delta nps2 strains, demonstrating that abnormal sexual development of Delta nps2 strains is at least partly due to their iron deficiency. Exogenous application of the natural siderophore ferricrocin to C. heterostrophus and G. zeae Delta nps2 strains restored WT fertility. NPS1, a G. zeae NPS gene that groups phylogenetically with NPS2, does not play a role in sexual development. Overall, these data demonstrate that iron and intracellular siderophores are essential for successful sexual development of the heterothallic ascomycete C. heterostrophus and the homothallic ascomycete G. zeae.
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Schroeder FC, Gibson DM, Churchill ACL, Sojikul P, Wursthorn EJ, Krasnoff SB, Clardy J. Differential analysis of 2D NMR spectra: new natural products from a pilot-scale fungal extract library. Angew Chem Int Ed Engl 2007; 46:901-4. [PMID: 17183517 DOI: 10.1002/anie.200603821] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Wach MJ, Krasnoff SB, Loria R, Gibson DM. Effect of carbohydrates on the production of thaxtomin A by Streptomyces acidiscabies. Arch Microbiol 2007; 188:81-8. [PMID: 17340119 DOI: 10.1007/s00203-007-0225-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Revised: 01/22/2007] [Accepted: 02/14/2007] [Indexed: 10/23/2022]
Abstract
Several Streptomyces species cause plant diseases, including S. scabies, S. acidiscabies and S. turgidiscabies, which produce common scab of potato and similar diseases of root crops. These species produce thaxtomins, dipeptide phytotoxins that are responsible for disease symptoms. Thaxtomins are produced in vivo on diseased potato tissue and in vitro in oat-based culture media, but the regulation of thaxtomin biosynthesis is not understood. S. acidiscabies was grown in a variety of media to assess the impact of medium components on thaxtomin A (ThxA) production. ThxA biosynthesis was not correlated with bacterial biomass, nor was it stimulated by alpha-solanine or alpha-chaconine, the two most prevalent potato glycoalkaloids. ThxA production was stimulated by oat bran broth, even after exhaustive extraction, suggesting that specific carbohydrates may influence ThxA biosynthesis. Oat bran contains high levels of xylans and glucans, and both of these carbohydrates, as well as xylans from wheat and tamarind, stimulated ThxA production, but not to the same extent as oat bran. Starches and simple sugars did not induce ThxA production. The data indicate that complex carbohydrates may act as environmental signals to plant pathogenic Streptomyces, allowing production of thaxtomin and enabling bacteria to colonize its host.
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Ketchum REB, Luong JV, Gibson DM. EFFICIENT EXTRACTION OF PACLITAXEL AND RELATED TAXOIDS FROM LEAF TISSUE OF TAXUS USING A POTABLE SOLVENT SYSTEM. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-100101762] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Pryor SW, Gibson DM, Bergstrom GC, Walker LP. Minimization of between-well sample variance of antifungal activity using a high-throughput screening microplate bioassay. Biotechniques 2007; 42:168, 170, 172. [PMID: 17373480 DOI: 10.2144/000112328] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Kornfeld A, Kaufman PB, Lu CR, Gibson DM, Bolling SF, Warber SL, Chang SC, Kirakosyan A. The production of hypericins in two selected Hypericum perforatum shoot cultures is related to differences in black gland structure. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2007; 45:24-32. [PMID: 17300946 DOI: 10.1016/j.plaphy.2006.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Indexed: 05/14/2023]
Abstract
In vitro shoot cultures of Hypericum perforatum derived from wild populations grown in Armenia have a wide variation of hypericin and pseudohypericin metabolite content. We found that a germ line denoted as HP3 produces six times more hypericin and fourteen times more pseudohypericin than a second line labeled HP1. We undertook a structural comparison of the two lines (HP1 and HP3) in order to see if there are any anatomical or morphological differences that could explain the differences in production of these economically important metabolites. Analysis by LM (light microscopy), SEM (scanning electron microscopy), and TEM (transmission electron microscopy) reveals that the hypericin/pseudohypericin-containing black glands located along the margins of the leaves consist of a peripheral sheath of flattened cells surrounding a core of interior cells that are typically dead at maturity. The peripheral cells of the HP3 glands appear less flattened than those of the HP1 glands. This may indicate that the peripheral cells are involved in hypericin/pseudohypericin production. Furthermore, we find that these peripheral cells undergo a developmental transition into the gland's interior cells. The fact that the size of the peripheral cells may correlate with metabolite production adds a new hypothesis for the actual site of hypericin synthesis.
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Krasnoff SB, Sommers CH, Moon YS, Donzelli BGG, Vandenberg JD, Churchill ACL, Gibson DM. Production of mutagenic metabolites by Metarhizium anisopliae. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:7083-8. [PMID: 16968066 DOI: 10.1021/jf061405r] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
NG-391 (1) and NG-393 (2), previously reported from undescribed Fusarium species as nerve-cell growth stimulants, were identified from fermentation extracts of the entomopathogenic fungus Metarhizium anisopliae. These compounds are 7-desmethyl analogues of fusarin C and (8Z)-fusarin C, mutagenic toxins from Fusarium species that contaminate corn. A mutant strain of M. anisopliae (KOB1-3) overproduces 1 and 2 by ca. 10-fold relative to the wild-type strain, ARSEF 2575, from which it was derived. Overproduction of these compounds in KOB1-3 imparts a yellow pigmentation to the culture medium of the fungus. These compounds were inactive at 100 mug/disk in antimicrobial disk diffusion assays. Compound 1 was inactive at 100 ppm in a mosquitocidal assay. However, like their fusarin analogues, 1 and 2 exhibited potent S9-dependent mutagenic activity in the Salmonella mutagenicity test. Discovery of these highly mutagenic mycotoxins in M. anisopliae suggests that screening for production of NG-391 and NG-393 in strains that are used as biocontrol agents would be a prudent course of action. The impact of these findings on the use of M. anisopliae as a biocontrol agent is currently unknown and requires further investigation.
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