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Karkhanis AN, Leach AC, Yorgason JT, Uneri A, Barth S, Niere F, Alexander NJ, Weiner JL, McCool BA, Raab-Graham KF, Ferris MJ, Jones SR. Chronic Social Isolation Stress during Peri-Adolescence Alters Presynaptic Dopamine Terminal Dynamics via Augmentation in Accumbal Dopamine Availability. ACS Chem Neurosci 2019; 10:2033-2044. [PMID: 30284806 DOI: 10.1021/acschemneuro.8b00360] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Chronic peri-adolescent stress in humans increases risk to develop a substance use disorder during adulthood. Rats reared in social isolation during peri-adolescence (aSI; 1 rat/cage) period show greater ethanol and cocaine intake compared to group housed (aGH; 4 rats/cage) rats. In addition, aSI rats have a heightened dopamine response in the nucleus accumbens (NAc) to rewarding and aversive stimuli. Furthermore, single pulse electrical stimulation in slices containing NAc core elicits greater dopamine release in aSI rats. Here, we further investigated dopamine release kinetics and machinery following aSI. Dopamine release, across a wide range of stimulation intensities and frequencies, was significantly greater in aSI rats. Interestingly, subthreshold intensity stimulations also resulted in measurable dopamine release in accumbal slices from aSI but not aGH rats. Extracellular [Ca2+] manipulations revealed augmented calcium sensitivity of dopamine release in aSI rats. The readily releasable pools of dopamine, examined by bath application of Ro-04-1284/000, a vesicular monoamine transporter 2 (VMAT2) inhibitor, were depleted faster in aGH rats. Western blot analysis of release machinery proteins (VMAT2, Synaptogyrin-3, Syntaxin-1, and Munc13-3) showed no difference between the two groups. Tyrosine hydroxylase (TH) protein expression levels, however, were elevated in aSI rats. The greater dopamine release could potentially be explained by higher levels of TH, the rate-limiting step for dopamine synthesis. This augmented responsivity of the dopamine system and heightened dopamine availability post-aSI may lead to an increased risk of addiction vulnerability.
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Affiliation(s)
- Anushree N. Karkhanis
- Department of Psychology and Developmental Exposure Alcohol Research Center, Binghamton University−SUNY, Binghamton, New York, United States
| | | | - Jordan T. Yorgason
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, United States
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2
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Lindo L, McCormick SP, Cardoza RE, Busman M, Alexander NJ, Proctor RH, Gutiérrez S. Requirement of Two Acyltransferases for 4- O-Acylation during Biosynthesis of Harzianum A, an Antifungal Trichothecene Produced by Trichoderma arundinaceum. J Agric Food Chem 2019; 67:723-734. [PMID: 30558420 DOI: 10.1021/acs.jafc.8b05564] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Trichothecenes are sesquiterpenoid toxins produced by multiple fungi, including plant pathogens, entomopathogens, and saprotrophs. Most of these fungi have the acyltransferase-encoding gene tri18. Even though its function has not been determined, tri18 is predicted to be involved in trichothecene biosynthesis because of its pattern of expression and its location near other trichothecene biosynthetic genes. Here, molecular genetic, precursor feeding, and analytical chemistry experiments indicate that in the saprotroph Trichoderma arundinaceum the tri18-encoded acyltransferase (TRI18) and a previously characterized acyltransferase (TRI3) are required for conversion of the trichothecene biosynthetic intermediate trichodermol to harzianum A, an antifungal trichothecene analog with an octa-2,4,6-trienedioyl acyl group. On the basis of the results, we propose that TRI3 catalyzes trichothecene 4- O-acetylation, and subsequently, TRI18 catalyzes replacement of the resulting acetyl group with octa-2,4,6-trienedioyl to form harzianum A. Thus, the findings provide evidence for a previously unrecognized two-step acylation process during trichothecene biosynthesis in T. arundinaceum and possibly other fungi.
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Affiliation(s)
- Laura Lindo
- Area of Microbiology , University of León, Campus de Ponferrada , Ponferrada 24400 , Spain
| | - Susan P McCormick
- Mycotoxin Prevention and Applied Microbiology Research Unit , National Center for Agricultural Utilization Research, United States Department of Agriculture , Peoria , Illinois 61604-3902 , United States
| | - Rosa E Cardoza
- Area of Microbiology , University of León, Campus de Ponferrada , Ponferrada 24400 , Spain
| | - Mark Busman
- Mycotoxin Prevention and Applied Microbiology Research Unit , National Center for Agricultural Utilization Research, United States Department of Agriculture , Peoria , Illinois 61604-3902 , United States
| | - Nancy J Alexander
- Mycotoxin Prevention and Applied Microbiology Research Unit , National Center for Agricultural Utilization Research, United States Department of Agriculture , Peoria , Illinois 61604-3902 , United States
| | - Robert H Proctor
- Mycotoxin Prevention and Applied Microbiology Research Unit , National Center for Agricultural Utilization Research, United States Department of Agriculture , Peoria , Illinois 61604-3902 , United States
| | - Santiago Gutiérrez
- Area of Microbiology , University of León, Campus de Ponferrada , Ponferrada 24400 , Spain
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3
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Lindo L, McCormick SP, Cardoza RE, Kim HS, Brown DW, Alexander NJ, Proctor RH, Gutiérrez S. Role of Trichoderma arundinaceum tri10 in regulation of terpene biosynthetic genes and in control of metabolic flux. Fungal Genet Biol 2019; 122:31-46. [DOI: 10.1016/j.fgb.2018.11.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/05/2018] [Accepted: 11/07/2018] [Indexed: 02/03/2023]
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4
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Lindo L, McCormick SP, Cardoza RE, Brown DW, Kim HS, Alexander NJ, Proctor RH, Gutiérrez S. Effect of deletion of a trichothecene toxin regulatory gene on the secondary metabolism transcriptome of the saprotrophic fungus Trichoderma arundinaceum. Fungal Genet Biol 2018; 119:29-46. [PMID: 30121242 DOI: 10.1016/j.fgb.2018.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/13/2018] [Accepted: 08/13/2018] [Indexed: 11/16/2022]
Abstract
Trichothecenes are terpenoid toxins produced by multiple fungal species with diverse lifestyles. In these fungi, the trichothecene biosynthetic gene (tri) cluster includes a gene encoding a Cys2His2 Zn-finger protein (TRI6). Analyses of plant pathogenic Fusarium species indicate that tri6 regulates tri gene expression. Here, we analyzed TRI6 function in the saprotrophic fungus Trichoderma arundinaceum, which produces the antimicrobial trichothecene harzianum A (HA). Deletion of the TRI6-encoding gene, tri6, blocked HA production and reduced expression of tri genes, and mevalonate biosynthetic genes required for synthesis of farnesyl diphosphate (FPP), the primary metabolite that feeds into trichothecene biosynthesis. In contrast, tri6 deletion did not affect expression of ergosterol biosynthetic genes required for synthesis of ergosterol from FPP, but did increase ergosterol production, perhaps because increased levels of FPP were available for ergosterol synthesis in the absence of trichothecene production. RNA-seq analyses indicated that genes in 10 of 49 secondary metabolite (SM) biosynthetic gene clusters in T. arundinaceum exhibited increased expression and five exhibited reduced expression in a tri6 deletion mutant (Δtri6). Despite the metabolic and transcriptional changes, Δtri6 mutants were not reduced in their ability to inhibit growth of fungal plant pathogens. Our results indicate that T. arundinaceum TRI6 regulates expression of both tri and mevalonate pathway genes. It remains to be determined whether the effects of tri6 deletion on expression of other SM clusters resulted because TRI6 can bind to promoter regions of cluster genes or because trichothecene production affects other SM pathways.
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Affiliation(s)
- Laura Lindo
- Area of Microbiology, University of León, Campus de Ponferrada, Ponferrada, Spain.
| | - Susan P McCormick
- National Center for Agricultural Utilization Research, United States Department of Agriculture, Peoria, IL, United States.
| | - Rosa E Cardoza
- Area of Microbiology, University of León, Campus de Ponferrada, Ponferrada, Spain.
| | - Daren W Brown
- National Center for Agricultural Utilization Research, United States Department of Agriculture, Peoria, IL, United States.
| | - Hye-Seon Kim
- National Center for Agricultural Utilization Research, United States Department of Agriculture, Peoria, IL, United States.
| | - Nancy J Alexander
- National Center for Agricultural Utilization Research, United States Department of Agriculture, Peoria, IL, United States
| | - Robert H Proctor
- National Center for Agricultural Utilization Research, United States Department of Agriculture, Peoria, IL, United States.
| | - Santiago Gutiérrez
- Area of Microbiology, University of León, Campus de Ponferrada, Ponferrada, Spain.
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5
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Alexander NJ, Rau AR, Jimenez VA, Daunais JB, Grant KA, McCool BA. SNARE Complex-Associated Proteins in the Lateral Amygdala of Macaca mulatta Following Long-Term Ethanol Drinking. Alcohol Clin Exp Res 2018; 42:1661-1673. [PMID: 29944190 DOI: 10.1111/acer.13821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/21/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Recent work with long-term ethanol (EtOH) self-administration in nonhuman primate models has revealed a complex array of behavioral and physiological effects that closely mimic human alcohol abuse. Detailed neurophysiological analysis in these models suggests a myriad of pre- and postsynaptic neurobiological effects that may contribute to the behavioral manifestations of long-term EtOH drinking. The molecular mechanisms regulating presynaptic effects of this chronic EtOH exposure are largely unknown. To this end, we analyzed the effects of long-term EtOH self-administration on the levels of presynaptic SNARE complex proteins in Macaca mulatta basolateral amygdala, a brain region known to regulate both aversive and reward-seeking behaviors. METHODS Basolateral amygdala samples from control and EtOH-drinking male and female monkeys were processed. Total basolateral amygdala protein was analyzed by Western blotting using antibodies directed against both core SNARE and SNARE-associated proteins. We also performed correlational analyses between protein expression levels and a number of EtOH drinking parameters, including lifetime grams of EtOH consumed, preference, and blood alcohol concentration. RESULTS Significant interactions or main effects of sex/drinking were seen for a number of SNARE core and SNARE-associated proteins. Across the range of EtOH-drinking phenotypes, SNAP25 and Munc13-1 proteins levels were significantly different between males and females, and Munc13-2 levels were significantly lower in animals with a history of EtOH drinking. A separate analysis of very heavy-drinking individuals revealed significant decreases in Rab3c (females) and complexin 2 (males). CONCLUSIONS Protein expression analysis of basolateral amygdala total protein from controls and animals following long-term EtOH self-administration suggests a number of alterations in core SNARE or SNARE-associated components that could dramatically alter presynaptic function. A number of proteins or multiprotein components were also correlated with EtOH drinking behavior, which suggest a potentially heritable role for presynaptic SNARE proteins.
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Affiliation(s)
- Nancy J Alexander
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Andrew R Rau
- Department of Behavioral Neuroscience, Oregon National Primate Research Center, Oregon Health Sciences University, Portland, Oregon
| | - Vanessa A Jimenez
- Department of Behavioral Neuroscience, Oregon National Primate Research Center, Oregon Health Sciences University, Portland, Oregon
| | - James B Daunais
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Kathleen A Grant
- Department of Behavioral Neuroscience, Oregon National Primate Research Center, Oregon Health Sciences University, Portland, Oregon
| | - Brian A McCool
- Department of Physiology & Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
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6
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McGinnis MM, Morales MM, Alexander NJ, McCool BA. Effects of chronic ethanol exposure and withdrawal on glutamatergic signaling at two afferent projections into the rat lateral/basolateral amygdala. Alcohol 2017. [DOI: 10.1016/j.alcohol.2017.02.307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Malmierca MG, Izquierdo-Bueno I, Mccormick SP, Cardoza RE, Alexander NJ, Moraga J, Gomes EV, Proctor RH, Collado IG, Monte E, Gutiérrez S. Botrydial and botcinins produced by Botrytis cinerea regulate the expression of Trichoderma arundinaceum genes involved in trichothecene biosynthesis. Mol Plant Pathol 2016; 17:1017-31. [PMID: 26575202 PMCID: PMC6638445 DOI: 10.1111/mpp.12343] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Trichoderma arundinaceum IBT 40837 (Ta37) and Botrytis cinerea produce the sesquiterpenes harzianum A (HA) and botrydial (BOT), respectively, and also the polyketides aspinolides and botcinins (Botcs), respectively. We analysed the role of BOT and Botcs in the Ta37-B. cinerea interaction, including the transcriptomic changes in the genes involved in HA (tri) and ergosterol biosynthesis, as well as changes in the level of HA and squalene-ergosterol. We found that, when confronted with B. cinerea, the tri biosynthetic genes were up-regulated in all dual cultures analysed, but at higher levels when Ta37 was confronted with the BOT non-producer mutant bcbot2Δ. The production of HA was also higher in the interaction area with this mutant. In Ta37-bcbot2Δ confrontation experiments, the expression of the hmgR gene, encoding the 3-hydroxy-3-methylglutaryl coenzyme A reductase, which is the first enzyme of the terpene biosynthetic pathway, was also up-regulated, resulting in an increase in squalene production compared with the confrontation with B. cinerea B05.10. Botcs had an up-regulatory effect on the tri biosynthetic genes, with BotcA having a stronger effect than BotcB. The results indicate that the interaction between Ta37 and B. cinerea exerts a stimulatory effect on the expression of the tri biosynthetic genes, which, in the interaction zone, can be attenuated by BOT produced by B. cinerea B05.10. The present work provides evidence for a metabolic dialogue between T. arundinaceum and B. cinerea that is mediated by sesquiterpenes and polyketides, and that affects the outcome of the interaction of these fungi with each other and their environment.
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Affiliation(s)
- Mónica G Malmierca
- Area of Microbiology, University School of Agricultural Engineers, University of León, Campus de Ponferrada, 24400 Ponferrada, Spain
| | - Inmaculada Izquierdo-Bueno
- Biomolecules Institute, Department of Organic Chemistry, Faculty of Sciences, University of Cádiz, 11510 Puerto Real, Spain
| | - Susan P Mccormick
- Mycotoxin Prevention and Applied Microbiology Research Unit, USDA/ARS, National Center for Agricultural Utilization Research, Peoria, 61604, IL, USA
| | - Rosa E Cardoza
- Area of Microbiology, University School of Agricultural Engineers, University of León, Campus de Ponferrada, 24400 Ponferrada, Spain
| | - Nancy J Alexander
- Mycotoxin Prevention and Applied Microbiology Research Unit, USDA/ARS, National Center for Agricultural Utilization Research, Peoria, 61604, IL, USA
| | - Javier Moraga
- Biomolecules Institute, Department of Organic Chemistry, Faculty of Sciences, University of Cádiz, 11510 Puerto Real, Spain
| | - Eriston V Gomes
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, 14040-900 Ribeirão Preto, SP, Brazil
| | - Robert H Proctor
- Mycotoxin Prevention and Applied Microbiology Research Unit, USDA/ARS, National Center for Agricultural Utilization Research, Peoria, 61604, IL, USA
| | - Isidro G Collado
- Biomolecules Institute, Department of Organic Chemistry, Faculty of Sciences, University of Cádiz, 11510 Puerto Real, Spain
| | - Enrique Monte
- Spanish-Portuguese Centre of Agricultural Research (CIALE), Department of Microbiology and Genetics, University of Salamanca, 37185, Salamanca, Spain
| | - Santiago Gutiérrez
- Area of Microbiology, University School of Agricultural Engineers, University of León, Campus de Ponferrada, 24400 Ponferrada, Spain
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8
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Malmierca MG, Izquierdo-Bueno I, McCormick SP, Cardoza RE, Alexander NJ, Barua J, Lindo L, Casquero PA, Collado IG, Monte E, Gutiérrez S. Trichothecenes and aspinolides produced by Trichoderma arundinaceum
regulate expression of Botrytis cinerea
genes involved in virulence and growth. Environ Microbiol 2016; 18:3991-4004. [DOI: 10.1111/1462-2920.13410] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 06/06/2016] [Indexed: 12/25/2022]
Affiliation(s)
- Mónica G. Malmierca
- Area of Microbiology; Universitary School of Agricultural Engineers. University of León; Ponferrada Spain
| | | | - Susan P. McCormick
- Mycotoxin Prevention and Applied Microbiology Research Unit, USDA/ARS; National Center for Agricultural Utilization Research; Peoria IL USA
| | - Rosa E. Cardoza
- Area of Microbiology; Universitary School of Agricultural Engineers. University of León; Ponferrada Spain
| | - Nancy J. Alexander
- Mycotoxin Prevention and Applied Microbiology Research Unit, USDA/ARS; National Center for Agricultural Utilization Research; Peoria IL USA
| | - Javier Barua
- Department of Organic Chemistry Faculty of Sciences; University of Cádiz; Puerto Real Spain
| | - Laura Lindo
- Area of Microbiology; Universitary School of Agricultural Engineers. University of León; Ponferrada Spain
| | - Pedro A. Casquero
- Research Group of Engineering and Sustainable Agriculture; Natural Resources Institute, University of León; León 24071 Spain
| | - Isidro G. Collado
- Department of Organic Chemistry Faculty of Sciences; University of Cádiz; Puerto Real Spain
| | - Enrique Monte
- Spanish-Portuguese Centre of Agricultural Research (CIALE), Department of Microbiology and Genetics; University of Salamanca; Salamanca Spain
| | - Santiago Gutiérrez
- Area of Microbiology; Universitary School of Agricultural Engineers. University of León; Ponferrada Spain
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9
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Malmierca MG, McCormick SP, Cardoza RE, Monte E, Alexander NJ, Gutiérrez S. Trichodiene Production in a Trichoderma harzianum erg1-Silenced Strain Provides Evidence of the Importance of the Sterol Biosynthetic Pathway in Inducing Plant Defense-Related Gene Expression. Mol Plant Microbe Interact 2015; 28:1181-1197. [PMID: 26168138 DOI: 10.1094/mpmi-06-15-0127-r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Trichoderma species are often used as biocontrol agents against plant-pathogenic fungi. A complex molecular interaction occurs among the biocontrol agent, the antagonistic fungus, and the plant. Terpenes and sterols produced by the biocontrol fungus have been found to affect gene expression in both the antagonistic fungus and the plant. The terpene trichodiene (TD) elicits the expression of genes related to tomato defense and to Botrytis virulence. We show here that TD itself is able to induce the expression of Botrytis genes involved in the synthesis of botrydial (BOT) and also induces terpene gene expression in Trichoderma spp. The terpene ergosterol, in addition to its role as a structural component of the fungal cell membranes, acts as an elicitor of defense response in plants. In the present work, using a transformant of T. harzianum, which is silenced in the erg1 gene and accumulates high levels of squalene, we show that this ergosterol precursor also acts as an important elicitor molecule of tomato defense-related genes and induces Botrytis genes involved in BOT biosynthesis, in both cases, in a concentration-dependent manner. Our data emphasize the importance of a balance of squalene and ergosterol in fungal interactions as well as in the biocontrol activity of Trichoderma spp.
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Affiliation(s)
- M G Malmierca
- 1 Area of Microbiology, Universitary School of Agricultural Engineers, University of León, Campus de Ponferrada. Avda, Astorga s/n, 24400 Ponferrada, Spain
| | - S P McCormick
- 2 Bacterial Foodborne Pathogen and Mycology Unit, USDA/ARS, National Center for Agricultural Utilization Research, Peoria, IL 61604-3902, U.S.A
| | - R E Cardoza
- 1 Area of Microbiology, Universitary School of Agricultural Engineers, University of León, Campus de Ponferrada. Avda, Astorga s/n, 24400 Ponferrada, Spain
| | - E Monte
- 3 Spanish-Portuguese Centre of Agricultural Research (CIALE), Department of Microbiology and Genetics, University of Salamanca, 37185 Salamanca, Spain
| | - N J Alexander
- 2 Bacterial Foodborne Pathogen and Mycology Unit, USDA/ARS, National Center for Agricultural Utilization Research, Peoria, IL 61604-3902, U.S.A
| | - S Gutiérrez
- 1 Area of Microbiology, Universitary School of Agricultural Engineers, University of León, Campus de Ponferrada. Avda, Astorga s/n, 24400 Ponferrada, Spain
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10
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Karkhanis AN, Alexander NJ, McCool BA, Weiner JL, Jones SR. Chronic social isolation during adolescence augments catecholamine response to acute ethanol in the basolateral amygdala. Synapse 2015; 69:385-95. [PMID: 25963724 DOI: 10.1002/syn.21826] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 04/07/2015] [Accepted: 04/17/2015] [Indexed: 01/18/2023]
Abstract
Adolescent social isolation (SI) results in numerous behavioral alterations associated with increased risk of alcoholism. Notably, many of these changes involve the basolateral amygdala (BLA), including increased alcohol seeking. The BLA sends a strong glutamatergic projection to the nucleus accumbens and activation of this pathway potentiates reward-seeking behavior. Dopamine (DA) and norepinephrine (NE) exert powerful excitatory and inhibitory effects on BLA activity and chronic stress can disrupt the excitation-inhibition balance maintained by these catecholamines. Notably, the impact of SI on BLA DA and NE neurotransmission is unknown. Thus the aim of this study was to characterize SI-mediated catecholamine alterations in the BLA. Male Long Evans rats were housed in groups of four (GH) or in SI for 6 weeks during adolescence. DA and NE transporter levels were then measured using Western blot hybridization and baseline and ethanol-stimulated DA and NE levels were quantified using microdialysis. DA transporter levels were increased and baseline DA levels were decreased in SI compared to GH rats. SI also increased DA responses to an acute ethanol (2 g kg(-1)) challenge. While no group differences were noted in NE transporter or baseline NE levels, acute ethanol (2 g kg(-1)) only significantly increased NE levels in SI animals. Collectively, these SI-dependent changes in BLA catecholamine signaling may lead to an increase in BLA excitability and a strengthening of the glutamatergic projection between the BLA and NAc. Such changes may promote the elevated ethanol drinking behavior observed in rats subjected to chronic adolescent stress.
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Affiliation(s)
- Anushree N Karkhanis
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina.,Translational Center for the Neurobehavioral Study of Alcohol, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Nancy J Alexander
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Brian A McCool
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina.,Translational Center for the Neurobehavioral Study of Alcohol, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jeffrey L Weiner
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina.,Translational Center for the Neurobehavioral Study of Alcohol, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Sara R Jones
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina.,Translational Center for the Neurobehavioral Study of Alcohol, Wake Forest School of Medicine, Winston-Salem, North Carolina
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11
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Malmierca MG, Barua J, McCormick SP, Izquierdo-Bueno I, Cardoza RE, Alexander NJ, Hermosa R, Collado IG, Monte E, Gutiérrez S. Novel aspinolide production by Trichoderma arundinaceum with a potential role in Botrytis cinerea antagonistic activity and plant defence priming. Environ Microbiol 2014; 17:1103-18. [PMID: 24889745 DOI: 10.1111/1462-2920.12514] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 05/14/2014] [Indexed: 11/28/2022]
Abstract
Harzianum A (HA), a trichothecene produced by Trichoderma arundinaceum, has recently been described to have antagonistic activity against fungal plant pathogens and to induce plant defence genes. In the present work, we have shown that a tri5 gene-disrupted mutant that lacks HA production overproduces two polyketides, aspinolides B and C, which were not detected in the wild-type strain. Furthermore, four new aspinolides (D-G) were characterized. These compounds confirm that a terpene-polyketide cross-pathway exists in T. arundinaceum, and they may be responsible for the antifungal activity and the plant sensitization effect observed with the tri5-disrupted mutant. In addition, the molecular changes involving virulence factors in the phytopathogenic fungus Botrytis cinerea 98 (Bc98) during interaction with T. arundinaceum were investigated. The expression of genes involved in the production of botrydial by Bc98 was relatively repressed by HA, whereas other virulence genes of this pathogen were induced by the presence of T. arundinaceum, for example atrB and pg1 which encode for an ABC transporter and endopolygalacturonase 1 respectively. In addition, the interaction with Bc98 significantly repressed the production of HA by T. arundinaceum, indicating that a bidirectional transcriptional regulation is established between these two antagonistic fungi.
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Affiliation(s)
- Mónica G Malmierca
- Area of Microbiology, Universitary School of Agricultural Engineers, University of León, Campus de Ponferrada, Avda. Astorga s/n, Ponferrada, 24400, Spain
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12
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Malmierca MG, McCormick SP, Cardoza RE, Alexander NJ, Monte E, Gutiérrez S. Production of trichodiene by T
richoderma harzianum
alters the perception of this biocontrol strain by plants and antagonized fungi. Environ Microbiol 2014; 17:2628-46. [DOI: 10.1111/1462-2920.12506] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/05/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Mónica G. Malmierca
- Area of Microbiology; Universitary School of Agricultural Engineers; University of León; Campus de Ponferrada, Avda. Astorga s/n Ponferrada 24400 Spain
| | - Susan P. McCormick
- Bacterial Foodborne Pathogen and Mycology Unit; National Center for Agricultural Utilization Research; USDA/ARS; Peoria IL USA
| | - Rosa E. Cardoza
- Area of Microbiology; Universitary School of Agricultural Engineers; University of León; Campus de Ponferrada, Avda. Astorga s/n Ponferrada 24400 Spain
| | - Nancy J. Alexander
- Bacterial Foodborne Pathogen and Mycology Unit; National Center for Agricultural Utilization Research; USDA/ARS; Peoria IL USA
| | - Enrique Monte
- Spanish-Portuguese Centre of Agricultural Research (CIALE); Department of Microbiology and Genetics; University of Salamanca; Salamanca Spain
| | - Santiago Gutiérrez
- Area of Microbiology; Universitary School of Agricultural Engineers; University of León; Campus de Ponferrada, Avda. Astorga s/n Ponferrada 24400 Spain
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Malmierca MG, Cardoza RE, Alexander NJ, McCormick SP, Collado IG, Hermosa R, Monte E, Gutiérrez S. Relevance of trichothecenes in fungal physiology: disruption of tri5 in Trichoderma arundinaceum. Fungal Genet Biol 2013; 53:22-33. [PMID: 23454546 DOI: 10.1016/j.fgb.2013.02.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Revised: 01/20/2013] [Accepted: 02/08/2013] [Indexed: 10/27/2022]
Abstract
Trichothecenes are sesquiterpenoid mycotoxins produced mainly by Fusarium species. Harzianum A (HA), a non-phytotoxic trichothecene produced by Trichoderma arundinaceum, has recently been found to have antagonistic activity against fungal plant pathogens and to induce plant genes involved in defense responses. In the present work, we have shown that disruption of the T. arundinaceum tri5 gene, which encodes a terpene synthase, stops the production of HA, alters the expression of other tri genes involved in HA biosynthesis, and alters the expression of hmgR, dpp1, erg9, erg1, and erg7, all genes involved in terpene biosynthetic pathways. An increase in the level of ergosterol biosynthesis was also observed in the tri5 disrupted transformant in comparison with the wild type strain. The loss of HA also resulted in a drastic reduction of the biocontrol activity of the transformants against the phytopathogenic fungi Botrytis cinerea and Rhizoctonia solani. Finally, the effect of tri5 gene disruption on the regulation and balance of intermediates in terpene biosynthetic pathways, as well as the hypothetical physiological role of trichothecenes, both inter- and intracellularly, on regulation and biocontrol, are discussed.
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Affiliation(s)
- Mónica G Malmierca
- Area of Microbiology, University School of Agricultural Engineers, University of León, Campus de Ponferrada, Avda. Astorga s/n, 24400 Ponferrada, Spain
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Christian DT, Alexander NJ, Diaz MR, McCool BA. Thalamic glutamatergic afferents into the rat basolateral amygdala exhibit increased presynaptic glutamate function following withdrawal from chronic intermittent ethanol. Neuropharmacology 2013; 65:134-42. [PMID: 22982568 PMCID: PMC3521082 DOI: 10.1016/j.neuropharm.2012.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 12/28/2022]
Abstract
Amygdala glutamatergic neurotransmission regulates withdrawal induced anxiety-like behaviors following chronic ethanol exposure. The lateral/basolateral amygdala receives multiple glutamatergic projections that contribute to overall amygdala function. Our lab has previously shown that rat cortical (external capsule) afferents express postsynaptic alterations during chronic intermittent ethanol exposure and withdrawal. However, thalamic (internal capsule) afferents also provide crucial glutamatergic input during behavioral conditioning, and they have not been studied in the context of chronic drug exposure. We report here that these thalamic inputs express altered presynaptic function during withdrawal from chronic ethanol exposure. This is characterized by enhanced release probability, as exemplified by altered paired-pulse ratios and decreased failure rates of unitary events, and increased concentrations of synaptic glutamate. Quantal analysis further implicates a withdrawal-dependent enhancement of the readily releasable pool of vesicles as a probable mechanism. These functional alterations are accompanied by increased expression of vesicle associated protein markers. These data demonstrate that chronic ethanol modulation of glutamate neurotransmission in the rat lateral/basolateral amygdala is afferent-specific. Further, presynaptic regulation of lateral/basolateral amygdala thalamic inputs by chronic ethanol may be a novel neurobiological mechanism contributing to the increased anxiety-like behaviors that characterize withdrawal.
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Affiliation(s)
- Daniel T Christian
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
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Christian DT, Alexander NJ, Diaz MR, Robinson S, McCool BA. Chronic intermittent ethanol and withdrawal differentially modulate basolateral amygdala AMPA-type glutamate receptor function and trafficking. Neuropharmacology 2012; 62:2430-9. [PMID: 22387532 DOI: 10.1016/j.neuropharm.2012.02.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/15/2012] [Accepted: 02/16/2012] [Indexed: 12/19/2022]
Abstract
The amygdala plays a critical role in the generation and expression of anxiety-like behaviors including those expressed following withdrawal (WD) from chronic intermittent ethanol (CIE) exposure. In particular, the BLA glutamatergic system controls the expression of both innate and pathological anxiety. Recent data suggests that CIE and WD may functionally alter this system in a manner that closely parallels memory-related phenomena like long-term potentiation (LTP). We therefore specifically dissected CIE/WD-induced changes in glutamatergic signaling using electrophysiological and biochemical approaches with a particular focus on the plasticity-related components of this neurotransmitter system. Our results indicate that cortical glutamatergic inputs arriving at BLA principal via the external capsule undergo predominantly post-synaptic alterations in AMPA receptor function following CIE and WD. Biochemical analysis revealed treatment-dependent changes in AMPA receptor surface expression and subunit phosphorylation that are complemented by changes in total protein levels and/or phosphorylation status of several key, plasticity-associated protein kinases such as calcium/calmodulin-dependent protein kinase II (CaMKII) and protein kinase C (PKC). Together, these data show that CIE- and WD-induced changes in BLA glutamatergic function both functionally and biochemically mimic plasticity-related states. These mechanisms likely contribute to long-term increases in anxiety-like behavior following chronic ethanol exposure.
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Affiliation(s)
- Daniel T Christian
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
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McCormick SP, Stanley AM, Stover NA, Alexander NJ. Trichothecenes: from simple to complex mycotoxins. Toxins (Basel) 2011; 3:802-14. [PMID: 22069741 PMCID: PMC3202860 DOI: 10.3390/toxins3070802] [Citation(s) in RCA: 292] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 06/10/2011] [Accepted: 06/29/2011] [Indexed: 01/07/2023] Open
Abstract
As the world's population grows, access to a safe food supply will continue to be a global priority. In recent years, the world has experienced an increase in mycotoxin contamination of grains due to climatic and agronomic changes that encourage fungal growth during cultivation. A number of the molds that are plant pathogens produce trichothecene mycotoxins, which are known to cause serious human and animal toxicoses. This review covers the types of trichothecenes, their complexity, and proposed biosynthetic pathways of trichothecenes.
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Affiliation(s)
- Susan P. McCormick
- Bacterial Foodborne Pathogens and Mycology, National Center for Agricultural Utilization Research, U.S. Department of Agriculture-Agriculture Research Service, Peoria, IL 61604, USA;
- Author to whom correspondence should be addressed; ; Tel.:+1-309-681-6381; Fax:+1-309-681-6627
| | - April M. Stanley
- Biology Department, Bradley University, Peoria, IL 61625, USA; (A.M.S.); (N.A.S.)
| | - Nicholas A. Stover
- Biology Department, Bradley University, Peoria, IL 61625, USA; (A.M.S.); (N.A.S.)
| | - Nancy J. Alexander
- Bacterial Foodborne Pathogens and Mycology, National Center for Agricultural Utilization Research, U.S. Department of Agriculture-Agriculture Research Service, Peoria, IL 61604, USA;
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Alexander NJ, McCormick SP, Waalwijk C, van der Lee T, Proctor RH. The genetic basis for 3-ADON and 15-ADON trichothecene chemotypes in Fusarium. Fungal Genet Biol 2011; 48:485-95. [PMID: 21216300 DOI: 10.1016/j.fgb.2011.01.003] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 12/28/2010] [Accepted: 01/03/2011] [Indexed: 11/30/2022]
Abstract
Certain Fusarium species cause head blight of wheat and other small grains worldwide and produce trichothecene mycotoxins. These mycotoxins can induce toxicoses in animals and humans and can contribute to the ability of some fusaria to cause plant disease. Production of the trichothecene 3-acetyldeoxynivalenol (3-ADON) versus 15-acetyldeoxynivalenol (15-ADON) is an important phenotypic difference within and among some Fusarium species. However, until now, the genetic basis for this difference in chemotype has not been identified. Here, we identified consistent DNA sequence differences in the coding region of the trichothecene biosynthetic gene TRI8 in 3-ADON and 15-ADON strains. Functional analyses of the TRI8 enzyme (Tri8) in F. graminearum, the predominant cause of wheat head blight in North America and Europe, revealed that Tri8 from 3-ADON strains catalyzes deacetylation of the trichothecene biosynthetic intermediate 3,15-diacetyldeoxynivalenol at carbon 15 to yield 3-ADON, whereas Tri8 from 15-ADON strains catalyzes deacetylation of 3,15-diacetyldeoxynivalenol at carbon 3 to yield 15-ADON. Fusarium strains that produce the trichothecene nivalenol have a Tri8 that functions like that in 15-ADON strains. TRI3, which encodes a trichothecene carbon 15 acetyltransferase, was found to be functional in all three chemotypes. Together, our data indicate that differential activity of Tri8 determines the 3-ADON and 15-ADON chemotypes in Fusarium.
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Affiliation(s)
- Nancy J Alexander
- Bacterial Foodborne Pathogen and Mycology Research Unit, National Center for Agricultural Utilization Research, ARS, USDA, Peoria, IL 61604, USA.
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Jeppsson H, Alexander NJ, Hahn-Hagerdal B. Existence of Cyanide-Insensitive Respiration in the Yeast Pichia stipitis and Its Possible Influence on Product Formation during Xylose Utilization. Appl Environ Microbiol 2010; 61:2596-600. [PMID: 16535073 PMCID: PMC1388491 DOI: 10.1128/aem.61.7.2596-2600.1995] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A cyanide-insensitive and salicyl hydroxamic acid-sensitive respiration (CIR) was found in the yeast Pichia stipitis in contrast to Candida utilis, Pachysolen tannophilus, and Saccharomyces cerevisiae. During xylose utilization in the presence of either salicyl hydroxamic acid or cyanide, P. stipitis formed xylitol, arabitol, and ribitol. The existence of CIR is discussed in terms of a redox sink preventing xylitol formation in P. stipitis.
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Proctor RH, McCormick SP, Alexander NJ, Desjardins AE. Evidence that a secondary metabolic biosynthetic gene cluster has grown by gene relocation during evolution of the filamentous fungus Fusarium. Mol Microbiol 2009; 74:1128-42. [PMID: 19843228 DOI: 10.1111/j.1365-2958.2009.06927.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Trichothecenes are terpene-derived secondary metabolites produced by multiple genera of filamentous fungi, including many plant pathogenic species of Fusarium. These metabolites are of interest because they are toxic to animals and plants and can contribute to pathogenesis of Fusarium on some crop species. Fusarium graminearum and F. sporotrichioides have trichothecene biosynthetic genes (TRI) at three loci: a 12-gene TRI cluster and two smaller TRI loci that consist of one or two genes. Here, comparisons of additional Fusarium species have provided evidence that TRI loci have a complex evolutionary history that has included loss, non-functionalization and rearrangement of genes as well as trans-species polymorphism. The results also indicate that the TRI cluster has expanded in some species by relocation of two genes into it from the smaller loci. Thus, evolutionary forces have driven consolidation of TRI genes into fewer loci in some fusaria but have maintained three distinct TRI loci in others.
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Affiliation(s)
- Robert H Proctor
- U. S. Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Peoria, IL, USA.
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20
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Garvey GS, McCormick SP, Alexander NJ, Rayment I. Structural and functional characterization of TRI3 trichothecene 15-O-acetyltransferase from Fusarium sporotrichioides. Protein Sci 2009; 18:747-61. [PMID: 19319932 DOI: 10.1002/pro.80] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Fusarium head blight is a devastating disease of cereal crops whose worldwide incidence is increasing and at present there is no satisfactory way of combating this pathogen or its associated toxins. There is a wide variety of trichothecene mycotoxins and they all contain a 12,13-epoxytrichothecene skeleton but differ in their substitutions. Indeed, there is considerable variation in the toxin profile across the numerous Fusarium species that has been ascribed to differences in the presence or absence of biosynthetic enzymes and their relative activity. This article addresses the source of differences in acetylation at the C15 position of the trichothecene molecule. Here, we present the in vitro structural and biochemical characterization of TRI3, a 15-O-trichothecene acetyltransferase isolated from F. sporotrichioides and the "in vivo" characterization of Deltatri3 mutants of deoxynivalenol (DON) producing F. graminearum strains. A kinetic analysis shows that TRI3 is an efficient enzyme with the native substrate, 15-decalonectrin, but is inactive with either DON or nivalenol. The structure of TRI3 complexed with 15-decalonectrin provides an explanation for this specificity and shows that Tri3 and Tri101 (3-O-trichothecene acetyltransferase) are evolutionarily related. The active site residues are conserved across all sequences for TRI3 orthologs, suggesting that differences in acetylation at C15 are not due to differences in Tri3. The tri3 deletion mutant shows that acetylation at C15 is required for DON biosynthesis even though DON lacks a C15 acetyl group. The enzyme(s) responsible for deacetylation at the 15 position of the trichothecene mycotoxins have not been identified.
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Affiliation(s)
- Graeme S Garvey
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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22
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Liu ZL, Palmquist DE, Ma M, Liu J, Alexander NJ. Application of a master equation for quantitative mRNA analysis using qRT-PCR. J Biotechnol 2009; 143:10-6. [PMID: 19539678 DOI: 10.1016/j.jbiotec.2009.06.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Revised: 05/27/2009] [Accepted: 06/09/2009] [Indexed: 12/01/2022]
Abstract
The qRT-PCR has been widely accepted as the assay of choice for mRNA quantification. For conventional practice, housekeeping genes have been applied as internal reference for data normalization and analysis since the technology appeared. However, housekeeping genes vary under different conditions and environmental stimuli and no commonly accepted housekeeping gene references are available. Accurate data acquisition and data reproducibility remain challenging and it is difficult to compare results from different experimental sources. Using yeast and a Fusarium fungus as examples, we demonstrate the independent performance of a sole reference gene, CAB, designated as a constant manual threshold for data acquisition, normalization, and analysis for multiple plate reactions. A robust master equation based on the CAB reference and the set of calibration control genes thereafter was established to estimate mRNA abundance for the same RNA background reactions. A valid range of amplification efficiency between 95% and 100% was observed for the control genes in different RNA background applied on an ABI real time PCR 7500 system. This newly developed robust quality control system provides a reliable means for absolute quantification of mRNA using the qRT-PCR, simplifies the conventional qRT-PCR procedures, and increases data reliability, reproducibility, and throughput of the assay.
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Affiliation(s)
- Z Lewis Liu
- National Center for Agricultural Utilization Research, USDA-ARS 1815N University St. Peoria, IL 61604, USA.
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23
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Alexander NJ, McCormick SP, Blackburn JA. Effects of xanthotoxin treatment on trichothecene production in Fusarium sporotrichioides. Can J Microbiol 2009; 54:1023-31. [PMID: 19096457 DOI: 10.1139/w08-100] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There are 4 P450 oxygenases involved in the biosynthesis of T-2 toxin in Fusarium sporotrichioides. Exactly how these enzymes react to antimicrobial plant defense compounds is unknown. Xanthotoxin (8-methoxypsoralen) is a phototoxic furanocoumarin that acts as a P450 oxygenase inhibitor. The current study shows that the addition of concentrations of 1.0 mmol/L or less of xanthotoxin to liquid cultures of F. sporotrichioides NRRL3299 can effectively block T-2 toxin production and cause an increase in accumulation of trichodiene, the hydrocarbon precursor of trichothecenes. The addition of xanthotoxin to liquid cultures of a trichodiene-accumulating F. sporotrichioides Tri4- mutant caused a 3- to 10-fold increase in trichodiene accumulation, suggesting that xanthotoxin not only blocks trichothecene oxygenation reactions, but may in some way also promote the synthesis of trichodiene. Feeding studies showed that 2 of the 4 P450 oxygenases, TRI4 and TRI1, were more sensitive to xanthotoxin, while oxygenases TRI11 and TRI13 were unaffected. Quantitative reverse-transcriptase PCR indicated that several of the genes in the toxin biosynthetic pathway were upregulated by xanthotoxin, with Tri4 showing the highest increase in expression. These results indicate that while xanthotoxin inhibits specific P450 oxygenase activity, it also has an effect on gene expression.
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Affiliation(s)
- Nancy J Alexander
- Mycotoxin Research Unit, National Center for Agricultural Utilization Research, ARS/USDA, 1815 N. University St, Peoria, IL61604, USA.
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Abstract
The biosyntheses of both macrocyclic trichothecenes in Myrothecium roridum and simple trichothecenes in Fusarium species begin with the cyclization of farnesyl pyrophosphate to form the sesquiterpene hydrocarbon trichodiene. A previous study showed that Myrothecium has a cluster of 3 genes that are homologous with Fusarium trichothecene genes: Tri4, a P450 oxygenase; Tri5, the sesquiterpene cyclase; and Tri6, a zinc-finger regulatory gene. Fusarium graminearum Tri4 (FgTri4) and M. roridum MrTri4 (MrTri4) have 66.9% identity. In this study, MrTri4 was expressed in Fusarium verticillioides. Liquid cultures of transformant strains expressing MrTri4 converted exogenous trichodiene to isotrichodiol, indicating that MrTri4 controls 3 oxygenation steps and that the product of MrTRI4 is isotrichodiol.
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Affiliation(s)
- Susan P McCormick
- Mycotoxin Research Unit, US Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, 1815 North University Avenue, Peoria, IL 61604-3902, USA.
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Harris LJ, Alexander NJ, Saparno A, Blackwell B, McCormick SP, Desjardins AE, Robert LS, Tinker N, Hattori J, Piché C, Schernthaner JP, Watson R, Ouellet T. A novel gene cluster in Fusarium graminearum contains a gene that contributes to butenolide synthesis. Fungal Genet Biol 2007; 44:293-306. [PMID: 17175185 DOI: 10.1016/j.fgb.2006.11.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 10/02/2006] [Accepted: 11/02/2006] [Indexed: 11/17/2022]
Abstract
The development of expressed sequence tag (EST) databases, directed transformation and a sequenced genome has facilitated the functional analysis of Fusarium graminearum genes. Extensive analysis of 10,397 ESTs, derived from thirteen cDNA libraries of F. graminearum grown under diverse conditions, identified a novel cluster of eight genes (gene loci fg08077-fg08084) located within a 17kb region of genomic sequence contig 1.324. The expression of these genes is concomitantly up-regulated under growth conditions that promote mycotoxin production. Gene disruption and add-back experiments followed by metabolite analysis of the transformants indicated that one of the genes, fg08079, is involved in butenolide synthesis. The mycotoxin butenolide is produced by several Fusarium species and has been suggested, but not proven, to be associated with tall fescue toxicoses in grazing cattle. This is the first report of the identification of a gene involved in the biosynthetic pathway of butenolide.
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Affiliation(s)
- L J Harris
- Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, Ottawa, Ont, Canada.
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Abstract
Fusarium graminearum and Fusarium sporotrichioides produce the trichothecene mycotoxins 15-acetyldeoxynivalenol and T-2 toxin, respectively. In both species, disruption of the P450 monooxygenase-encoding gene, Tri4, blocks production of the mycotoxins and leads to the accumulation of the trichothecene precursor trichodiene. To further characterize its function, the F. graminearum Tri4 (FgTri4) was heterologously expressed in the trichothecene-nonproducing species Fusarium verticillioides. Transgenic F. verticillioides carrying the FgTri4 converted exogenous trichodiene to the trichothecene biosynthetic intermediates isotrichodermin and trichothecene. Conversion of trichodiene to isotrichodermin requires seven biochemical steps. The fifth and sixth steps can occur nonenzymatically. Precursor feeding studies done in the current study indicate that wild-type F. verticillioides has the enzymatic activity necessary to carry out the seventh step, the C-3 acetylation of isotrichodermol to form isotrichodermin. Together, the results of this study indicate that the Tri4 protein catalyzes the remaining four steps and is therefore a multifunctional monooxygenase required for trichothecene biosynthesis.
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Affiliation(s)
- Susan P McCormick
- Mycotoxin Research Unit, United States Department of Agriculture-Agriculture Research Service (USDA-ARS), National Center for Agricultural Utilization Research, IL 61604-3902, USA.
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27
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Abstract
Fusarium graminearum Z-3639 and F. sporotrichioides NRRL3299 produce the trichothecene mycotoxins 15-acetyldeoxynivalenol and T-2 toxin, respectively. These toxins differ in oxygenation at C-4, C-7, and C-8. In F. sporotrichioides, Tri1 (FsTri1) controls C-8 hydroxylation. To determine the function of an apparent F. graminearum Tri1 (FgTri1) homolog, both FsTri1 and FgTri1 genes were heterologously expressed in the trichothecene-nonproducing species F. verticillioides by fusing the Tri1 coding regions to the promoter of the fumonisin biosynthetic gene FUM8. FsTri1 and FgTri1 have been partially characterized by disruption analysis, and the results from these analyses suggest that FsTri1 most likely has a single function but that FgTri1 may have two functions. Transgenic F. verticillioides carrying the FsTri1 (FvF8FsTri1) converted exogenous isotrichodermin and calonectrin to 8-hydroxyisotrichodermin and 8-hydroxycalonectrin, respectively. Transgenic F. verticillioides carrying FgTri1 (FvF8FgTri1) converted isotrichodermin to a mixture of 7-hydroxyisotrichodermin and 8-hydroxyisotrichodermin but converted calonectrin to a mixture of 7-hydroxycalonectrin, 8-hydroxycalonectrin, and 3,15-diacetyldeoxynivalenol. A fourth compound, 7,8-dihydroxycalonectrin, was identified in large-scale F. verticillioides FvF8FgTri1 cultures fed isotrichodermin. Our results indicate that FgTri1 controls both C-7 and C-8 hydroxylation but that FsTri1 controls only C-8 hydroxylation. Our studies also demonstrate that F. verticillioides can metabolize some trichothecenes by adding an acetyl group to C-3 or by removing acetyl groups from C-4 or C-15. In addition, wild-type F. verticillioides can convert 7,8-dihydroxycalonectrin to 3,15-diacetyldeoxynivalenol.
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Affiliation(s)
- Susan P McCormick
- Mycotoxin Research Unit, USDA, ARS, National Center for Agricultural Utilization Research, IL 61604-3902, USA.
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Desjardins AE, Jarosz AM, Plattner RD, Alexander NJ, Brown DW, Jurgenson JE. Patterns of trichothecene production, genetic variability, and virulence to wheat of Fusarium graminearum from smallholder farms in Nepal. J Agric Food Chem 2004; 52:6341-6346. [PMID: 15453711 DOI: 10.1021/jf040181e] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fusarium graminearum causes wheat head blight and contaminates grain with the trichothecenes 4-deoxynivalenol and nivalenol. Sequence analysis of trichothecene genes indicates that nivalenol production is the ancestral trait; however, deoxynivalenol producers occur worldwide and predominate in North and South America and in Europe. Analysis of a large field population (>500 strains) from Nepal identified three groups that were both genetically distinct and polymorphic for trichothecene production: SCAR1 comprising 95% deoxynivalenol producers, SCAR2 comprising 94% nivalenol producers, and SCAR3/5 comprising 34% deoxynivalenol producers/63% nivalenol producers. The ability to cause wheat head blight differed between SCAR groups and trichothecene chemotypes: deoxynivalenol producers were more virulent than nivalenol producers across all three SCAR groups and within the SCAR3/5 genetic background. These data support the hypothesis that production of deoxynivalenol rather than nivalenol confers a selective advantage to this important wheat pathogen.
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Affiliation(s)
- Anne E Desjardins
- Mycotoxin Research, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, Peoria, IL 61604, USA.
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McCormick SP, Harris LJ, Alexander NJ, Ouellet T, Saparno A, Allard S, Desjardins AE. Tri1 in Fusarium graminearum encodes a P450 oxygenase. Appl Environ Microbiol 2004; 70:2044-51. [PMID: 15066795 PMCID: PMC383062 DOI: 10.1128/aem.70.4.2044-2051.2004] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gibberella zeae (asexual state Fusarium graminearum) is a major causal agent of wheat head blight and maize ear rot in North America and is responsible for contamination of grain with deoxynivalenol and related trichothecene mycotoxins. To identify additional trichothecene biosynthetic genes, cDNA libraries were prepared from fungal cultures under trichothecene-inducing conditions in culture and in planta. A gene designated LH1 that was highly expressed under these conditions exhibited only moderate (59%) similarity to known trichothecene biosynthetic cytochrome P450s. To determine the function of LH1, gene disruptants were produced and assessed for trichothecene production. Gene disruptants no longer produced 15-acetyldeoxynivalenol, which is oxygenated at carbon 7 (C-7) and C-8, but rather accumulated calonectrin and 3-deacetylcalonectrin, which are not oxygenated at either C-7 or C-8. These results indicate that gene LH1 encodes a cytochrome P450 responsible for oxygenation at one or both of these positions. Despite the relatively low level of DNA and amino acid sequence similarity between the two genes, LH1 from G. zeae is the probable homologue of Tri1, which encodes a cytochrome P450 required for C-8 oxygenation in F. sporotrichioides.
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Affiliation(s)
- S P McCormick
- Mycotoxin Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, Peoria, Illinois 61604, USA.
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Alexander NJ, Baker E, Kaptein M, Karck U, Miller L, Zampaglione E. Why consider vaginal drug administration? Fertil Steril 2004; 82:1-12. [PMID: 15236978 DOI: 10.1016/j.fertnstert.2004.01.025] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Revised: 01/04/2004] [Accepted: 01/04/2004] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To review the anatomy and physiology of the vagina, the merits of vaginal drug administration, and the currently available vaginal drug-administration systems. DESIGN Review of basic and clinical research. RESULT(S) Although clinicians commonly use topically administered drugs in the vagina, this route for systemic drug administration is somewhat novel. Experience with a variety of products demonstrates that the vagina is a highly effective site for drug delivery, particularly in women's health. The vagina is often an ideal route for drug administration because it allows for the administration of lower doses, steady drug levels, and less frequent administration than the oral route. With vaginal drug administration, absorption is unaffected by gastrointestinal disturbances, there is no first-pass effect, and use is discreet. Knowledge of anatomy, physiology, histology, and immunology of the vagina should allow clinicians to reassure their patients concerning this mode of delivery. Greater understanding and experience by clinicians should lead to increased use and acceptance of the vagina as a route for drug administration. CONCLUSION(S) The safety and efficacy of vaginal administration have been well established. The vaginal route of drug delivery is acceptable and may even be a preferable route of administration for many drugs, particularly hormones, whether for contraception or postmenopausal estrogen therapy.
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Alexander NJ, McCormick SP, Larson TM, Jurgenson JE. Expression of Tri15 in Fusarium sporotrichioides. Curr Genet 2004; 45:157-62. [PMID: 14624310 DOI: 10.1007/s00294-003-0467-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2003] [Revised: 10/20/2003] [Accepted: 10/23/2003] [Indexed: 10/26/2022]
Abstract
In the fungus Fusarium sporotrichioides, biosynthesis of trichothecene mycotoxins requires at least three genetic loci: a core 12-gene cluster, a smaller two-gene cluster, and a single-gene locus. Here, we describe the Tri15 gene, which represents a fourth locus involved in trichothecene biosynthesis. Tri15 is predicted to encode a Cys(2)-His(2 )zinc finger protein and is expressed in a manner similar to genes in the core trichothecene gene cluster. However, disruption of F. sporotrichioides Tri15 does not affect production of T-2 toxin, the major trichothecene produced by this fungus. This result suggests that Tri15 is not necessary for the production of toxin. Cultures with exogenously added T-2 toxin have high levels of Tri15 expression and no detectable expression of the trichothecene biosynthetic genes Tri5 and Tri6. The expression analysis is consistent with Tri15 being a negative regulator of at least some of the trichothecene biosynthetic genes. In F. graminearum, Tri15 has been mapped to linkage group 2 and is therefore unlinked to the main trichothecene biosynthetic gene cluster.
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Affiliation(s)
- Nancy J Alexander
- Mycotoxin Research Unit, USDA/ARS, National Center for Agricultural Utilization Research, 1815 N. University St., Peoria, IL 61604, USA.
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Okubara PA, Blechl AE, McCormick SP, Alexander NJ, Dill-Macky R, Hohn TM. Engineering deoxynivalenol metabolism in wheat through the expression of a fungal trichothecene acetyltransferase gene. Theor Appl Genet 2002; 106:74-83. [PMID: 12582873 DOI: 10.1007/s00122-002-1066-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2001] [Accepted: 04/05/2002] [Indexed: 05/24/2023]
Abstract
Fusarium head blight occurs in cereals throughout the world and is especially important in humid growing regions. Fusarium head blight (FHB) has re-emerged as a major disease of wheat and barley in the U.S. and Canada since 1993. The primary causal agents of FHB, Fusarium graminearum and Fusarium culmorum, can produce deoxynivalenol (DON), a trichothecene mycotoxin that enhances disease severity and poses a health hazard to humans and monogastric animals. To reduce the effects of DON on wheat, we have introduced FsTRI101, a Fusarium sporotrichioides gene formerly known as TriR, into the regenerable cultivar Bobwhite. TRI101 encodes an enzyme that transfers an acetyl moiety to the C3 hydroxyl group of trichothecenes. Four different transgenic plants carrying the FsTRI101 gene were identified. Although expression levels varied among the four lines, all of them accumulated FsTRI101 transcripts in endosperm and glume. TRI101-encoded acetyltransferase activity was detected in endosperm extracts of a single plant that accumulated FsTRI101 mRNA. Greenhouse resistance tests indicated that the accumulation of FsTRI101-encoded acetyltransferase in this plant confers partial protection against the spread of F. graminearum in inoculated wheat heads (spikes).
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Affiliation(s)
- P A Okubara
- U.S. Department of Agriculture, Agricultural Research Service, Western Regional Research Center, 800 Buchanan Street, Albany, California 94710-1105, USA
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Alexander NJ, McCormick SP, Hohn TM. The identification of the Saccharomyces cerevisiae gene AYT1(ORF-YLL063c) encoding an acetyltransferase. Yeast 2002; 19:1425-30. [PMID: 12478589 DOI: 10.1002/yea.924] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The recent isolation and characterization of Tri101 in Fusarium sporotrichioides has led to the functional identification of the yeast open reading frame (ORF) YLL063c, located on chromosome XII of Saccharomyces cerevisiae. The sequence of YLL063c predicts a protein of 474 residues that has 45% identity and 70% similarity to FsTri101. FsTri101 encodes a trichothecene 3-O-acetyltransferase that functions in trichothecene biosynthesis. Feeding studies indicated low levels of C3-OH acetylation in cultures of the laboratory yeast strain, RW2802. No similar activity was found in RW2802 transformed with an integrative plasmid carrying a disrupted YLL063c gene. Based on these results, which show structural and functional similarities between YLL063c and FsTri101, we propose that YLL063c encodes an acetyltransferase capable of trichothecene 3-O-acetylation and have named this gene AYT1. Published in 2002 by John Wiley & Sons, Ltd.
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Abstract
This randomized, double-blind, placebo-controlled exploratory study examined the efficacy and safety of a low-dose oral contraceptive (Mircette), desogestrel/ethinyl estradiol [DSG/EE] and ethinyl estradiol [EE]) in relieving the symptoms of dysmenorrhea. Twenty-three clinics in the United States enrolled 77 women (age < or =32 years) with primary dysmenorrhea documented for at least four consecutive cycles. Forty participants received DSG/EE&EE and 37 received placebo for four consecutive 28-day cycles. The intensity of menstrual-related distress was measured with the Menstrual Distress Questionnaire (MDQ). Patient diaries were used to assess number of school/work days missed as well as the use of rescue medication. Participants receiving DSG/EE&EE recorded reduced menstrual pain severity, lower total MDQ scores, and significantly less menstrual cramping. No significant change in bloating, anxiety, loneliness, weight gain, or acne was reported. The DSG/EE&EE formulation shows promise for the treatment of primary dysmenorrhea and was well tolerated by the participants in this study.
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Brown DW, McCormick SP, Alexander NJ, Proctor RH, Desjardins AE. Inactivation of a cytochrome P-450 is a determinant of trichothecene diversity in Fusarium species. Fungal Genet Biol 2002; 36:224-33. [PMID: 12135578 DOI: 10.1016/s1087-1845(02)00021-x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Species of the genus Fusarium produce a great diversity of agriculturally important trichothecene toxins that differ from each other in their pattern of oxygenation and esterification. T-2 toxin, produced by Fusarium sporotrichioides, and nivalenol (NIV), produced by some strains of F. graminearum, contain an oxygen at the C-4 position. Deoxynivalenol (DON), produced by other strains of F. graminearum, lacks a C-4 oxygen. NIV and DON are identical except for this difference, whereas T-2 differs from these trichothecenes at three other carbon positions. Sequence and Northern analyses of the F. sporotrichioides genomic region upstream of the previously described core trichothecene gene cluster have extended the cluster by two genes: TRI13 and TRI14. TRI13 shares significant similarity with the cytochrome P-450 class of enzymes, but TRI14 does not share similarity with any previously characterized proteins. Gene disruption and fermentation studies in F. sporotrichioides indicate that TRI13 is required for the addition of the C-4 oxygen of T-2 toxin, but that TRI14 is not required for trichothecene biosynthesis. PCR and sequence analyses indicate that the TRI13 homolog is functional in NIV-producing strains of F. graminearum but nonfunctional in DON-producing strains of the fungus. These genetic observations are consistent with chemical observations that biosynthesis of T-2 toxin and NIV requires a C-4 hydroxylase while biosynthesis of DON does not.
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Affiliation(s)
- Daren W Brown
- Mycotoxin Research Unit, USDA/ARS, National Center for Agricultural Utilization Research, 1815 N. University St., Peoria, IL 61604, USA.
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Abstract
Mutant strains of Fusarium graminearum Z3639 produced by disruption of Tri8 were altered in their ability to biosynthesize 15-acetyldeoxynivalenol and instead accumulated 3,15-diacetyldeoxynivalenol, 7,8-dihydroxycalonectrin, and calonectrin. Fusarium sporotrichioides NRRL3299 Tri8 mutant strains accumulated 3-acetyl T-2 toxin, 3-acetyl neosolaniol, and 3,4,15-triacetoxyscirpenol rather than T-2 toxin, neosolaniol, and 4,15-diacetoxyscirpenol. The accumulation of these C-3-acetylated compounds suggests that Tri8 encodes an esterase responsible for deacetylation at C-3. This gene function was confirmed by cell-free enzyme assays and feeding experiments with yeast expressing Tri8. Previous studies have shown that Tri101 encodes a C-3 transacetylase that acts as a self-protection or resistance factor during biosynthesis and that the presence of a free C-3 hydroxyl group is a key component of Fusarium trichothecene phytotoxicity. Since Tri8 encodes the esterase that removes the C-3 protecting group, it may be considered a toxicity factor.
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Affiliation(s)
- Susan P McCormick
- Mycotoxin Research Unit, USDA/ARS, National Center for Agricultural Utilization Research, Peoria, Illinois 61604-3902, USA.
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Abstract
Trichothecenes are potent inhibitors of cytoplasmic protein synthesis which can affect the severity of plant diseases such as wheat head scab. While many trichothecene-producing fungi share the initial biosynthetic intermediates, Fusarium sp. are unique in the production of trichothecenes containing an oxygen function at C-3. Although the initial trichothecene and the final products have a C-3 hydroxyl group, the intermediate steps are acetylated at C-3. By using Chlamydomonas reinhardtii, a unicellular plant with a well-defined genetic system, we were able to test the proposal that trichothecenes with a C-3 hydroxyl are more toxic to plants, as well as demonstrate that C. reinhardtii is a promising plant trichothecene bioassay system. Seven pairs of trichothecenes with either a C-3 hydroxyl or C-3 acetyl group were assayed. Our results confirm that trichothecenes acetylated at C-3 were far less toxic to Chlamydomonas than those with a C-3 hydroxyl group.
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Affiliation(s)
- N J Alexander
- Mycotoxin Research Unit, USDA/ARS, National Center for Agricutural Utilization Research, Peoria, Illinois 61604, USA.
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Abstract
We constructed a genetic linkage map of Gibberella zeae (Fusarium graminearum) by crossing complementary nitrate-nonutilizing (nit) mutants of G. zeae strains R-5470 (from Japan) and Z-3639 (from Kansas). We selected 99 nitrate-utilizing (recombinant) progeny and analyzed them for amplified fragment length polymorphisms (AFLPs). We used 34 pairs of two-base selective AFLP primers and identified 1048 polymorphic markers that mapped to 468 unique loci on nine linkage groups. The total map length is approximately 1300 cM with an average interval of 2.8 map units between loci. Three of the nine linkage groups contain regions in which there are high levels of segregation distortion. Selection for the nitrate-utilizing recombinant progeny can explain two of the three skewed regions. Two linkage groups have recombination patterns that are consistent with the presence of intercalary inversions. Loci governing trichothecene toxin amount and type (deoxynivalenol or nivalenol) map on linkage groups IV and I, respectively. The locus governing the type of trichothecene produced (nivalenol or deoxynivalenol) cosegregated with the TRI5 gene (which encodes trichodiene synthase) and probably maps in the trichothecene gene cluster. This linkage map will be useful in population genetic studies, in map-based cloning, for QTL (quantitative trait loci) analysis, for ordering genomic libraries, and for genomic comparisons of related species.
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Affiliation(s)
- J E Jurgenson
- Department of Biology, University of Northern Iowa, Cedar Falls, Iowa 50614, USA.
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Brown DW, McCormick SP, Alexander NJ, Proctor RH, Desjardins AE. A Genetic and Biochemical Approach to Study Trichothecene Diversity in Fusarium sporotrichioides and Fusarium graminearum. Fungal Genet Biol 2001; 32:121-33. [PMID: 11352533 DOI: 10.1006/fgbi.2001.1256] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The trichothecenes T-2 toxin and deoxynivalenol (DON) are natural fungal products that are toxic to both animals and plants. Their importance in the pathogenicity of Fusarium spp. on crop plants has inspired efforts to understand the genetic and biochemical mechanisms leading to trichothecene synthesis. In order to better understand T-2 toxin biosynthesis by Fusarium sporotrichioides and DON biosynthesis by F. graminearum, we compared the nucleotide sequence of the 23-kb core trichothecene gene cluster from each organism. This comparative genetic analysis allowed us to predict proteins encoded by two trichothecene genes, TRI9 and TRI10, that had not previously been described from either Fusarium species. Differences in gene structure also were correlated with differences in the types of trichothecenes that the two species produce. Gene disruption experiments showed that F. sporotrichioides TRI7 (FsTRI7) is required for acetylation of the oxygen on C-4 of T-2 toxin. Sequence analysis indicated that F. graminearum TRI7 (FgTRI7) is nonfunctional. This is consistent with the fact that the FgTRI7 product is not required for DON synthesis in F. graminearum because C-4 is not oxygenated.
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Affiliation(s)
- D W Brown
- Mycotoxin Research Unit, USDA/ARS, Peoria, Illinois 61604, USA.
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Muhitch MJ, McCormick SP, Alexander NJ, Hohn TM. Transgenic expression of the TRI101 or PDR5 gene increases resistance of tobacco to the phytotoxic effects of the trichothecene 4,15-diacetoxyscirpenol. Plant Sci 2000; 157:201-207. [PMID: 10960733 DOI: 10.1016/s0168-9452(00)00282-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Mycotoxins are fungal secondary compounds that are toxic to vertebrates. Their presence in food and feeds, as the result of fungal disease in crops, can present a danger to animal or human health. Many mycotoxins have also been shown to be phytotoxic and in some cases, such as with trichothecenes produced by the wheat head blight fungus Fusarium graminearum, mycotoxins may act as virulence factors. Antibiotic-producing organisms, including fungi, protect themselves from their own toxins by metabolic alteration of the compound, modification of the target site of action or by exporting the compound to the extracellular space. We have tested the effectiveness of adapting two of these strategies, metabolic alteration and extracellular transport, to protect plant cells from the deleterious effects of the trichothecene 4,15-diacetoxyscirpenol (DAS). Tobacco plants were transformed with either the Saccharomyces cerevisiae gene PDR5, which encodes a multi-drug transporter, or with the Fusarium sporotrichioides gene TRI101, which encodes a trichothecene 3-O-acetyltransferase. Both genes conferred significant increased tolerance to DAS as measured by a sensitive seed germination assay. Expression of PDR5 or TRI101 in a seed-specific manner in crop plants such as wheat could lower the incidence of head blight as well as reduce mycotoxin levels within the seed.
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Affiliation(s)
- MJ Muhitch
- Mycotoxin Research Unit, National Center for Agricultural Utilization Research, ARS, USDA, 1815 North University Street, 61604, Peoria, IL, USA
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Alexander NJ. Over population is the biggest problem faced by our planet. J Androl 2000; 21:165. [PMID: 10670532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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McCormick SP, Alexander NJ, Trapp SE, Hohn TM. Disruption of TRI101, the gene encoding trichothecene 3-O-acetyltransferase, from Fusarium sporotrichioides. Appl Environ Microbiol 1999; 65:5252-6. [PMID: 10583973 PMCID: PMC91713 DOI: 10.1128/aem.65.12.5252-5256.1999] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We screened a Fusarium sporotrichioides NRRL 3299 cDNA expression library in a toxin-sensitive Saccharomyces cerevisiae strain lacking a functional PDR5 gene. Fourteen yeast transformants were identified as resistant to the trichothecene 4,15-diacetoxyscirpenol, and each carried a cDNA encoding the trichothecene 3-O-acetyltransferase that is the F. sporotrichioides homolog of the Fusarium graminearum TRI101 gene. Mutants of F. sporotrichioides NRRL 3299 produced by disruption of TRI101 were altered in their abilities to synthesize T-2 toxin and accumulated isotrichodermol and small amounts of 3, 15-didecalonectrin and 3-decalonectrin, trichothecenes that are not observed in cultures of the parent strain. Our results indicate that TRI101 converts isotrichodermol to isotrichodermin and is required for the biosynthesis of T-2 toxin.
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Affiliation(s)
- S P McCormick
- Mycotoxin Research Unit, USDA/ARS National Center for Agricultural Utilization Research, Peoria, Illinois 61604, USA.
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Alexander NJ, McCormick SP, Hohn TM. TRI12, a trichothecene efflux pump from Fusarium sporotrichioides: gene isolation and expression in yeast. Mol Gen Genet 1999; 261:977-84. [PMID: 10485289 DOI: 10.1007/s004380051046] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Many of the genes involved in trichothecene toxin biosynthesis in Fusarium sporotrichioides are present within a gene cluster. Here we report the complete sequence for TRI12, a gene encoding a trichothecene efflux pump that is located within the trichothecene gene cluster of F. sporotrichioides. TRI12 encodes a putative polypeptide of 598 residues with sequence similarities to members of the major facilitator superfamily (MFS) and is predicted to contain 14 transmembrane-spanning segments. Disruption of TRI12 results in both reduced growth on complex media and reduced levels of trichothecene production. Growth of tri12 mutants on trichothecene-containing media is inhibited, suggesting that TRI12 may play a role in F. sporotrichioides self-protection against trichothecenes. Functional analysis of TRI12 was performed by expressing it in yeast strains that were co-transformed with a gene (TRI3) encoding a trichothecene 15-O-acetyltransferase. In the presence of the TRI3 substrate, 15-decalonectrin, cultures of yeast strains carrying TRI12 and TRI3 accumulated much higher levels of the acetylated product, calonectrin, than was observed for strains carrying TRI3 alone. PDR5, a transporter of the ABC superfamily, which is known to mediate trichothecene resistance in yeast, increased calonectrin accumulation in TRI12/TRI3 yeast strains but not in TRI3 strains. These results confirm the involvement of TRI12 in the trichothecene efflux associated with toxin biosynthesis, and demonstrate the usefulness of yeast as a host system for studies of MFS-type transporters.
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Affiliation(s)
- N J Alexander
- Mycotoxin Research Unit, USDA/ARS, National Center for Agricultural Utilization Research, Peoria, IL 61604, USA
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Alexander NJ. Contraception: present and future. Med J Indones 1999. [DOI: 10.13181/mji.v8i1.671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Abstract
Whether semen from someone who is HIV-positive can be prepared so that it is safe for insemination is a critical question particularly to couples in which the male is seropositive and the female is seronegative. It is reassuring that some investigators have reported great success in using sperm washing to dramatically reduce HIV levels in the ejaculate. Such reports suggest that if free virus and leukocytes in the seminal plasma are removed, the specimen may be safe for insemination. Whether the virus ever is associated with spermatozoa themselves is not fully understood. In situ hybridization as well as electron microscopic studies have suggested the presence of viral particles but whether these are preparation artifacts or evidence of viable viral DNA is not known. Studies of whether the virus is incorporated into developing spermatozoa or is shed in the reproductive tract will aid in the elucidation of sexual transmission of HIV.
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Alexander NJ, Hohn TM, McCormick SP. The TRI11 gene of Fusarium sporotrichioides encodes a cytochrome P-450 monooxygenase required for C-15 hydroxylation in trichothecene biosynthesis. Appl Environ Microbiol 1998; 64:221-5. [PMID: 9435078 PMCID: PMC124697 DOI: 10.1128/aem.64.1.221-225.1998] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Several genes in the trichothecene biosynthetic pathway of Fusarium sporotrichioides have been shown to reside in a gene cluster. Sequence analysis of a cloned DNA fragment located 3.8 kb downstream from TRI5 has led to the identification of the TRI11 gene. The nucleotide sequence of TRI11 predicts a polypeptide of 492 residues (Mr = 55,579) with significant similarity to members of the cytochrome P-450 superfamily. TRI11 is most similar to several fungal cytochromes P-450 (23 to 27% identity) but is sufficiently distinct to define a new cytochrome P-450 gene family, designated CYP65A1. Disruption of TRI11 results in an altered trichothecene production phenotype characterized by the accumulation of isotrichodermin, a trichothecene pathway intermediate. The evidence suggests that TRI11 encodes a C-15 hydroxylase involved in trichothecene biosynthesis.
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Affiliation(s)
- N J Alexander
- Mycotoxin Research Unit, National Center for Agricultural Utilization Research, U.S. Department of Agriculture/Agricultural Research Service, Peoria, Illinois 61604, USA
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Barditch-Crovo P, Witter F, Hamzeh F, McPherson J, Stratton P, Alexander NJ, Trapnell CB. Quantitation of vaginally administered nonoxynol-9 in premenopausal women. Contraception 1997; 55:261-3. [PMID: 9179459 DOI: 10.1016/s0010-7824(97)00003-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A feasibility study was performed in 11 healthy nonpregnant premenopausal women to determine a method for collection and recovery of vaginally administered nonoxynol-9. We also determined if nonoxynol-9 could be quantitated in vaginal lavage fluid obtained 2 h after instillation of a standard precoitol dose of a foam formulation of nonoxynol-9. Samples were analyzed in batch using a validated normal phase high-performance liquid chromatography (HPLC) method. Two hours after instillation of one dose of Delfen Contraceptive Foam (100 mg), the quantity of nonoxynol-9 collected ranged from 10.8 to 67.8 mg (mean: 35.4 mg). This corresponds to a recovery of 11.70%, of the administered dose. Quantitation of vaginally administered nonoxynol-9 is both practical and feasible. These data represent a critical first step in the evaluation of the safety and effectiveness of nonoxynol-9-containing products in the prevention of sexually transmitted diseases.
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Affiliation(s)
- P Barditch-Crovo
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
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