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Fodor J, Nagy JK, Király L, Mészáros K, Bányai J, Cséplő MK, Schwarczinger I, Künstler A. Heat Treatments at Varying Ambient Temperatures and Durations Differentially Affect Plant Defense to Blumeria hordei in a Resistant and a Susceptible Hordeum vulgare Line. Phytopathology 2024; 114:418-426. [PMID: 37665321 DOI: 10.1094/phyto-06-23-0191-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 09/05/2023]
Abstract
Our previous research showed that a powdery mildew resistant barley line (MvHV07-17) maintains its resistance to Blumeria hordei (Bh) even if plants are exposed to a long-term high temperature of 35°C for 120 h before Bh inoculation, whereas such high temperature pretreatment further increases susceptibility to infection in the susceptible barley line MvHV118-17. In the present study, we extended this approach using short-term high-temperature water treatment (49°C for 30 s) to determine how it affects powdery mildew resistance in these barley lines. We found that this short-term heat shock (HS) impaired plant defense responses, as reflected by development of Bh colonies and visible necrotic spots on leaves of MvHV07-17, which does not develop visible symptoms upon Bh inoculation under optimal growth conditions. In contrast, both HS and long-term heat stress enhanced susceptibility to Bh in MvHV118-17 plants. These results were supported by the measurement of Bh biomass using a qPCR method. Furthermore, microscopic examinations showed that HS elevated the rate of successful Bh penetration events and the spread of cell death in the surrounding mesophyll area and allowed for colony formation and sporulation in resistant barley, whereas early and effective plant defense responses, such as papilla formation and single-cell epidermal hypersensitive response, were significantly reduced. Furthermore, we found that the accumulation of hydrogen peroxide in both resistant and susceptible barley was correlated with susceptibility induced by HS and long-term heat-stress. This study may contribute to a better understanding of plant defense responses to Bh in barley exposed to heat. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- József Fodor
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Judit Kolozsváriné Nagy
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Lóránt Király
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Klára Mészáros
- Cereal Breeding Department, Agricultural Institute, Centre for Agricultural Research, ELKH, H-2462, Martonvásár, Hungary
| | - Judit Bányai
- Cereal Breeding Department, Agricultural Institute, Centre for Agricultural Research, ELKH, H-2462, Martonvásár, Hungary
| | - Mónika Károlyiné Cséplő
- Cereal Breeding Department, Agricultural Institute, Centre for Agricultural Research, ELKH, H-2462, Martonvásár, Hungary
| | - Ildikó Schwarczinger
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - András Künstler
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
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Király L, Zechmann B, Albert R, Bacsó R, Schwarczinger I, Kolozsváriné Nagy J, Gullner G, Hafez YM, Künstler A. Enhanced Resistance to Viruses in Nicotiana edwardsonii 'Columbia' Is Dependent on Salicylic Acid, Correlates with High Glutathione Levels, and Extends to Plant-Pathogenic Bacteria and Abiotic Stress. Mol Plant Microbe Interact 2024; 37:36-50. [PMID: 37750816 DOI: 10.1094/mpmi-07-23-0106-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 09/27/2023]
Abstract
Our earlier research showed that an interspecific tobacco hybrid (Nicotiana edwardsonii 'Columbia' [NEC]) displays elevated levels of salicylic acid (SA) and enhanced resistance to localized necrotic symptoms (hypersensitive response [HR]) caused by tobacco mosaic virus (TMV) and tobacco necrosis virus (TNV), as compared with another interspecific hybrid (Nicotiana edwardsonii [NE]) derived from the same parents. In the present study, we investigated whether symptomatic resistance in NEC is indeed associated with the inhibition of TMV and TNV and whether SA plays a role in this process. We demonstrated that enhanced viral resistance in NEC is manifested as both milder local necrotic (HR) symptoms and reduced levels of TMV and TNV. The presence of an adequate amount of SA contributes to the enhanced defense response of NEC to TMV and TNV, as the absence of SA resulted in seriously impaired viral resistance. Elevated levels of subcellular tripeptide glutathione (GSH) in NEC plants in response to viral infection suggest that in addition to SA, GSH may also contribute to the elevated viral resistance of NEC. Furthermore, we found that NEC displays an enhanced resistance not only to viral pathogens but also to bacterial infections and abiotic oxidative stress induced by paraquat treatments. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Lóránt Király
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Bernd Zechmann
- Center for Microscopy and Imaging, Baylor University, One Bear Place, no. 97046, Waco, TX 76798, U.S.A
| | - Réka Albert
- Institute of Plant Sciences and Environmental Protection, Faculty of Agriculture, University of Szeged, H-6800, Hódmezővásárhely, Hungary
| | - Renáta Bacsó
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Ildikó Schwarczinger
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Judit Kolozsváriné Nagy
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Gábor Gullner
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
| | - Yaser Mohamed Hafez
- EPCRS Excellence Center & Plant Pathology and Biotechnology Lab, Department of Agricultural Botany, Faculty of Agriculture, Kafrelsheikh University, 33516 Kafr-El-Sheikh, Egypt
| | - András Künstler
- Department of Plant Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, ELKH, H-1022, Budapest, Hungary
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Kolozsváriné Nagy J, Móricz ÁM, Böszörményi A, Ambrus Á, Schwarczinger I. Antibacterial effect of essential oils and their components against Xanthomonas arboricola pv. pruni revealed by microdilution and direct bioautographic assays. Front Cell Infect Microbiol 2023; 13:1204027. [PMID: 37389207 PMCID: PMC10303133 DOI: 10.3389/fcimb.2023.1204027] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 06/01/2023] [Indexed: 07/01/2023] Open
Abstract
Bacterial spot of stone fruits caused by Xanthomonas arboricola pv. pruni (Xap) is one of the most significant diseases of several Prunus species. Disease outbreaks can result in severe economic losses while the control options are limited. Antibacterial efficacy of essential oils (EOs) of thyme, cinnamon, clove, rosemary, tea tree, eucalyptus, lemon grass, citronella grass, and lemon balm was assessed against two Hungarian Xap isolates. The minimal inhibitory concentration (MIC) was determined by broth microdilution assay and for the identification of active EOs' components a newly introduced high-performance thin-layer chromatography (HPTLC)-Xap (direct bioautography) method combined with solid-phase microextraction-gas chromatography/mass spectrometry (SPME-GC/MS) was applied. All EOs inhibited both bacterium isolates, but cinnamon proved to be the most effective EO with MIC values of 31.25 µg/mL and 62.5 µg/mL, respectively. Compounds in the antibacterial HPTLC zones were identified as thymol in thyme, trans-cinnamaldehyde in cinnamon, eugenol in clove, borneol in rosemary, terpinen-4-ol in tea tree, citral (neral and geranial) in lemon grass and lemon balm, and citronellal and nerol in citronella grass. Regarding active compounds, thymol had the highest efficiency with a MIC value of 50 µg/mL. Antibacterial effects of EOs have already been proven for several Xanthomonas species, but to our knowledge, the studied EOs, except for lemon grass and eucalyptus, were tested for the first time against Xap. Furthermore, in case of Xap, this is the first report demonstrating that direct bioautography is a fast and suitable method for screening anti-Xap components of complex matrices, like EOs.
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Affiliation(s)
- Judit Kolozsváriné Nagy
- Plant Protection Institute, Centre for Agricultural Research, Eötvös Lóránd Research Network, Budapest, Hungary
| | - Ágnes M. Móricz
- Plant Protection Institute, Centre for Agricultural Research, Eötvös Lóránd Research Network, Budapest, Hungary
| | - Andrea Böszörményi
- Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Semmelweis University, Budapest, Hungary
| | - Ágnes Ambrus
- Plant Health Bacteriological Diagnostic National Reference Laboratory, Food Chain Safety Laboratory Directorate, National Food Chain Safety Office, Pécs, Hungary
| | - Ildikó Schwarczinger
- Plant Protection Institute, Centre for Agricultural Research, Eötvös Lóránd Research Network, Budapest, Hungary
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Baglyas M, Ott PG, Schwarczinger I, Nagy JK, Darcsi A, Bakonyi J, Móricz ÁM. Antimicrobial Diterpenes from Rough Goldenrod ( Solidago rugosa Mill.). Molecules 2023; 28:molecules28093790. [PMID: 37175200 PMCID: PMC10180332 DOI: 10.3390/molecules28093790] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023] Open
Abstract
Solidago rugosa is one of the goldenrod species native to North America but has sporadically naturalized as an alien plant in Europe. The investigation of the root and leaf ethanol extracts of the plant using a bioassay-guided process with an anti-Bacillus assay resulted in the isolation of two antimicrobial components. Structure elucidation was performed based on high-resolution tandem mass spectrometric and one- and two-dimensional NMR spectroscopic analyses that revealed (-)-hardwickiic acid (Compound 1) and (-)-abietic acid (Compound 2). The isolates were evaluated for their antimicrobial properties against several plant pathogenic bacterial and fungal strains. Both compounds demonstrated an antibacterial effect, especially against Gram-positive bacterial strains (Bacillus spizizenii, Clavibacter michiganensis subsp. michiganensis, and Curtobacterium flaccumfaciens pv. flaccumfaciens) with half maximal inhibitory concentration (IC50) between 1 and 5.1 µg/mL (5-20 times higher than that of the positive control gentamicin). In the used concentrations, minimal bactericidal concentration (MBC) was reached only against the non-pathogen B. spizizenii. Besides their activity against Fusarium avenaceum, the highest antifungal activity was observed for Compound 1 against Bipolaris sorokiniana with an IC50 of 3.8 µg/mL.
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Affiliation(s)
- Márton Baglyas
- Plant Protection Institute, Centre for Agricultural Research, ELKH, Herman O. Str. 15, 1022 Budapest, Hungary
- Doctoral School of Pharmaceutical Sciences, Semmelweis University, Hőgyes E. Str. 7-9, 1092 Budapest, Hungary
| | - Péter G Ott
- Plant Protection Institute, Centre for Agricultural Research, ELKH, Herman O. Str. 15, 1022 Budapest, Hungary
| | - Ildikó Schwarczinger
- Plant Protection Institute, Centre for Agricultural Research, ELKH, Herman O. Str. 15, 1022 Budapest, Hungary
| | - Judit Kolozsváriné Nagy
- Plant Protection Institute, Centre for Agricultural Research, ELKH, Herman O. Str. 15, 1022 Budapest, Hungary
| | - András Darcsi
- Pharmaceutical Chemistry and Technology Department, National Institute of Pharmacy and Nutrition, Szabolcs Str. 33, 1135 Budapest, Hungary
| | - József Bakonyi
- Plant Protection Institute, Centre for Agricultural Research, ELKH, Herman O. Str. 15, 1022 Budapest, Hungary
| | - Ágnes M Móricz
- Plant Protection Institute, Centre for Agricultural Research, ELKH, Herman O. Str. 15, 1022 Budapest, Hungary
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Kolozsváriné Nagy J, Schwarczinger I, Király L, Bacsó R, Ádám AL, Künstler A. Near-Isogenic Barley Lines Show Enhanced Susceptibility to Powdery Mildew Infection Following High-Temperature Stress. Plants 2022; 11:plants11070903. [PMID: 35406883 PMCID: PMC9003484 DOI: 10.3390/plants11070903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 11/16/2022]
Abstract
Barley cultivation is adversely affected by high-temperature stress, which may modulate plant defense responses to pathogens such as barley powdery mildew (Blumeria graminis f. sp. hordei, Bgh). Earlier research focused mainly on the influence of short-term heat stress (heat shock) of barley on Bgh infection. In this study, our aim was to investigate the effects of both short- and long-term heat stress (35 °C from 30 s to 5 days) on Bgh infection in the barley cultivar Ingrid and its near-isogenic lines containing different powdery mildew resistance genes (Mla12, Mlg, and mlo5) by analyzing symptom severity and Bgh biomass with RT-qPCR. The expression of selected barley defense genes (BAX inhibitor-1, Pathogenesis- related protein-1b, Respiratory burst oxidase homologue F2, and Heat shock protein 90-1) was also monitored in plants previously exposed to heat stress followed by inoculation with Bgh. We demonstrated that pre-exposure to short- and long-term heat stress negatively affects the resistance of all resistant lines manifested by the appearance of powdery mildew symptoms and increased Bgh biomass. Furthermore, prolonged heat stress (48 and 120 h) enhanced both Bgh symptoms and biomass in susceptible wild-type Ingrid. Heat stress suppressed and delayed early defense gene activation in resistant lines, which is a possible reason why resistant barley became partially susceptible to Bgh.
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Schwarczinger I, Kolozsváriné Nagy J, Király L, Mészáros K, Bányai J, Kunos V, Fodor J, Künstler A. Heat Stress Pre-Exposure May Differentially Modulate Plant Defense to Powdery Mildew in a Resistant and Susceptible Barley Genotype. Genes (Basel) 2021; 12:genes12050776. [PMID: 34069722 PMCID: PMC8160753 DOI: 10.3390/genes12050776] [Citation(s) in RCA: 3] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/17/2021] [Accepted: 05/17/2021] [Indexed: 11/16/2022] Open
Abstract
Heat stress negatively affects barley production and under elevated temperatures defense responses to powdery mildew (Blumeria graminis f. sp. hordei, Bgh) are altered. Previous research has analyzed the effects of short-term (30 s to 2 h) heat stress, however, few data are available on the influence of long-term exposure to heat on powdery mildew infections. We simultaneously assessed the effects of short and long term heat pre-exposure on resistance/susceptibility of barley to Bgh, evaluating powdery mildew infection by analyzing symptoms and Bgh biomass with RT-qPCR in barley plants pre-exposed to high temperatures (28 and 35 °C from 30 s to 5 days). Plant defense gene expression after heat stress pre-exposure and inoculation was also monitored. Our results show that prolonged heat stress (24, 48 and 120 h) further enhanced Bgh susceptibility in a susceptible barley line (MvHV118-17), while a resistant line (MvHV07-17) retained its pathogen resistance. Furthermore, prolonged heat stress significantly repressed the expression of several defense-related genes (BAX inhibitor-1, Pathogenesis related-1b and Respiratory burst oxidase homologue F2) in both resistant and susceptible barley lines. Remarkably, heat-suppressed defense gene expression returned to normal levels only in MvHV07-17, a possible reason why this barley line retains Bgh resistance even at high temperatures.
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Affiliation(s)
- Ildikó Schwarczinger
- Centre for Agricultural Research, Plant Protection Institute, ELKH, 15 Herman Ottó Str., H-1022 Budapest, Hungary; (I.S.); (J.K.N.); (J.F.); (A.K.)
| | - Judit Kolozsváriné Nagy
- Centre for Agricultural Research, Plant Protection Institute, ELKH, 15 Herman Ottó Str., H-1022 Budapest, Hungary; (I.S.); (J.K.N.); (J.F.); (A.K.)
| | - Lóránt Király
- Centre for Agricultural Research, Plant Protection Institute, ELKH, 15 Herman Ottó Str., H-1022 Budapest, Hungary; (I.S.); (J.K.N.); (J.F.); (A.K.)
- Correspondence: ; Tel.: +36-1-487-7527
| | - Klára Mészáros
- Centre for Agricultural Research, Agricultural Institute, ELKH, 2 Brunszvik Str., H-2462 Martonvásár, Hungary; (K.M.); (J.B.); (V.K.)
| | - Judit Bányai
- Centre for Agricultural Research, Agricultural Institute, ELKH, 2 Brunszvik Str., H-2462 Martonvásár, Hungary; (K.M.); (J.B.); (V.K.)
| | - Viola Kunos
- Centre for Agricultural Research, Agricultural Institute, ELKH, 2 Brunszvik Str., H-2462 Martonvásár, Hungary; (K.M.); (J.B.); (V.K.)
| | - József Fodor
- Centre for Agricultural Research, Plant Protection Institute, ELKH, 15 Herman Ottó Str., H-1022 Budapest, Hungary; (I.S.); (J.K.N.); (J.F.); (A.K.)
| | - András Künstler
- Centre for Agricultural Research, Plant Protection Institute, ELKH, 15 Herman Ottó Str., H-1022 Budapest, Hungary; (I.S.); (J.K.N.); (J.F.); (A.K.)
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Szatmári Á, Móricz ÁM, Schwarczinger I, Kolozsváriné Nagy J, Alberti Á, Pogány M, Bozsó Z. A pattern-triggered immunity-related phenolic, acetosyringone, boosts rapid inhibition of a diverse set of plant pathogenic bacteria. BMC Plant Biol 2021; 21:153. [PMID: 33765920 PMCID: PMC7992983 DOI: 10.1186/s12870-021-02928-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 03/10/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Acetosyringone (3,5-dimethoxy-4-hydroxyacetophenone, AS) is a syringyl-type phenolic compound rarely found in plants in free form. It has been shown earlier to inhibit the growth of Pseudomonas bacteria in the presence of hydrogen peroxide and peroxidase (AS mix). RESULTS We detected elevated levels of free AS in Nicotiana tabacum and N. benthamiana plants after inducing pattern-triggered immunity (PTI) by injecting bacterial elicitor flg22, or pathogenicity-mutant Pseudomonas syringae pv. syringae 61 hrcC- bacteria; but not after inoculations with compatible or incompatible pathogens at the time of PTI onset. In this study, we demonstrate that the antibacterial effect of the AS mix is general, as growth of several Gram-negative and -positive phytopathogenic bacteria was characteristically inhibited. The inhibition of bacterial metabolism by the AS mix was rapid, shown by the immediate drop of luminescence intensity of P. syringae pv. tomato DC3000 lx strain after addition of AS mix. The mechanism of the bacteriostatic effect was investigated using fluorescent reporter dye assays. SYTOX Green experiments supported others' previous findings that the AS mix does not result in membrane permeabilization. Moreover, we observed that the mode of action could be depolarization of the bacterial cell membrane, as shown by assays carried out with the voltage sensitive dye DIBAC4(3). CONCLUSIONS Level of free acetosyringone is elevated during plant PTI responses in tobacco leaves (N. tabacum and N. benthamiana). When combined with hydrogen peroxide and peroxidase (AS mix), components of the mix act synergistically to inhibit bacterial metabolism and proliferation rapidly in a wide range of plant pathogens. This effect is related to depolarization rather than to permeabilization of the bacterial cell membrane. Similar AS mixture to the in vivo model might form locally at sites of invading bacterial attachment to the plant cells and the presence of acetosyringone might have an important role in the inhibition of bacterial proliferation during PTI.
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Affiliation(s)
- Ágnes Szatmári
- Plant Protection Institute, ELKH Centre for Agricultural Research, Herman Ottó St. 15, Budapest, 1022, Hungary.
- Present address: Chemical Biology Research Group, Institute of Organic Chemistry, ELKH Research Centre for Natural Sciences, Magyar tudósok körútja 2, Budapest, 1117, Hungary.
| | - Ágnes M Móricz
- Plant Protection Institute, ELKH Centre for Agricultural Research, Herman Ottó St. 15, Budapest, 1022, Hungary
| | - Ildikó Schwarczinger
- Plant Protection Institute, ELKH Centre for Agricultural Research, Herman Ottó St. 15, Budapest, 1022, Hungary
| | - Judit Kolozsváriné Nagy
- Plant Protection Institute, ELKH Centre for Agricultural Research, Herman Ottó St. 15, Budapest, 1022, Hungary
| | - Ágnes Alberti
- Department of Pharmacognosy, Faculty of Pharmacy, Semmelweis University, Üllői St. 26, Budapest, 1085, Hungary
| | - Miklós Pogány
- Plant Protection Institute, ELKH Centre for Agricultural Research, Herman Ottó St. 15, Budapest, 1022, Hungary
| | - Zoltán Bozsó
- Plant Protection Institute, ELKH Centre for Agricultural Research, Herman Ottó St. 15, Budapest, 1022, Hungary.
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Abstract
Despite the relevance of membrane protein misfolding to a number of common diseases, our understanding of the folding and misfolding of membrane proteins lags well behind soluble proteins. Here, the overall kinetics of membrane insertion and folding of the homotrimeric integral membrane protein diacylglycerol kinase (DAGK) is addressed. DAGK was purified into lipid/detergent-free urea and guanidinium solutions and subjected to general structural characterization. In urea, the enzyme was observed to be monomeric but maintained considerable tertiary structure. In guanidinium, it was also monomeric but exhibited much less tertiary structure. Aliquots of these DAGK stock solutions were diluted 200-fold into lipid vesicles or into detergent/lipid mixed micelles, and the rates and efficiencies of folding/insertion were monitored. Reactions were also carried out in which micellar DAGK solutions were diluted into vesicular solutions. Productive insertion of DAGK from denaturant solutions into mixed micelles occurred much more rapidly than into lipid vesicles, suggesting that bilayer transversal represents the rate-limiting step for DAGK assembly in vesicles. The efficiency of productive folding/insertion into vesicles was highest in reactions initiated with micellar DAGK stock solutions (where DAGK maintains a nativelike fold and oligomeric state) and lowest in reactions starting with guanidinium stocks (where DAGK is an unfolded monomer). Moreover, the final ratio of irreversibly misfolded DAGK to reversibly misfolded enzyme was highest following reactions initiated with guanidinium stock solutions and lowest when micellar stocks were used. Finally, it was also observed that very low concentrations of detergents were able to both enhance the bilayer insertion rate and suppress misfolding.
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Affiliation(s)
- J K Nagy
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106-4970, USA
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9
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Abstract
Data are presented which suggest that a class of amphiphilic polymers known as 'amphipols' may serve as a vehicle for delivering complex integral membrane proteins into membranes. The integral membrane protein diacylglycerol kinase (DAGK) was maintained in soluble form by either of two different amphipols. Small aliquots of these solutions were added to pre-formed lipid vesicles and the appearance of DAGK catalytic activity was monitored as an indicator of the progress of productive protein insertion into the bilayers. For one of the two amphipols tested, DAGK was observed to productively transfer from its amphipol complex into vesicles with moderate efficiency. Results were not completely clear for the other amphipol.
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Affiliation(s)
- J K Nagy
- Department of Physiology and Biophysics, Case Western Reserve University, Clelevand, OH 44106-4970, USA
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10
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Abstract
Protein misfolding is increasingly recognized as a factor in many diseases, including cystic fibrosis, Parkinson's, Alzheimer's and atherosclerosis. Many proteins involved in misfolding-based pathologies are membrane-associated, such that the bilayer may play roles in normal and aberrant folding. It can be argued that the in vivo partitioning of eukaryotic membrane proteins between folding and misfolding pathways is under kinetic control. Moreover, the balance between these pathways can be surprisingly delicate.
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Affiliation(s)
- C R Sanders
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106-4970, USA.
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Nagy JK, Lau FW, Bowie JU, Sanders CR. Mapping the oligomeric interface of diacylglycerol kinase by engineered thiol cross-linking: homologous sites in the transmembrane domain. Biochemistry 2000; 39:4154-64. [PMID: 10747807 DOI: 10.1021/bi991781n] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work represents the first stage of thiol-based cross-linking studies to map the oligomeric interface of the homotrimeric membrane protein diacylglycerol kinase (DAGK). A total of 53 single-cysteine mutants spanning DAGK's three transmembrane segments and the first part of a cytoplasmic domain were purified and subjected to catalytic oxidation in mixed micelles. Four mutants (A52C, I53C, A74C, and I75C) were observed to undergo intratrimer disulfide bond formation between homologous sites on adjacent subunits. To establish whether the homologous sites are proximal in the ground-state conformation of DAGK or whether the disulfide bonds formed as a result of motions that brought normally distal sites into transient proximity, additional cross-linking experiments were carried out in three different milieus of varying fluidity [mixed micelles, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) vesicles, and Escherichia coli membranes]. Cross-linking experiments included disulfide bond formation under three different catalytic conditions [Cu(II)-phenanthroline oxidation, I(2) oxidation, and thionitrobenzoate-based thiol exchange] and reactions with a set of bifunctional thiol-reactive chemical cross-linkers presenting two different reactive chemistries and several spacer lengths. On the basis of these studies, residues 53 and 75 are judged to be in stable proximity within the DAGK homotrimer, while position 52 appears to be more distal and forms disulfide bonds only as a result of protein motions. Results for position 74 were ambiguous. In lipid vesicles and mixed micelles DAGK appears to execute motions that are not present in native membranes, with mobility also being higher for DAGK in mixed micelles than in POPC vesicles.
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Affiliation(s)
- J K Nagy
- Department of Physiology, Case Western Reserve University, Cleveland, Ohio 44106-4970, USA
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Weaver DM, Tyler JW, Marion RS, Wallace LM, Nagy JK, Holle JM. Evaluation of assays for determination of passive transfer status in neonatal llamas and alpacas. J Am Vet Med Assoc 2000; 216:559-63. [PMID: 10687013 DOI: 10.2460/javma.2000.216.559] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [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]
Abstract
OBJECTIVE To evaluate several practice-adapted assays for determination of passive transfer status in crias. ANIMALS 24 llama and 9 alpaca crias. DESIGN Prospective study. PROCEDURE Serum IgG concentration was measured by use of a radial immunodiffusion assay when crias were 45 to 51 hours old. Results were compared with serum gamma-glutamyltransferase (GGT) activity, serum total protein, albumin, globulin, and total solids concentrations, and results of commercially available and traditional sodium sulfite turbidity (SST) tests. RESULTS Mean (+/- SD) serum IgG concentration was 1,762 +/- 1,153 mg/dl. On the basis of a threshold value of 1,000 mg of IgG/dl at 48 hours of age, 5 of 33 (15.15%) crias had failure of passive transfer. Serum total solids, protein, and globulin concentrations were significantly associated with serum IgG concentration, whereas serum GGT activity and serum albumin concentration were not. Serum IgG concentrations were significantly different among crias with negative, 2+, and 3+ scores on the traditional SST test. Serum IgG concentrations were not significantly different between crias with negative and 100 mg/dl scores or 100 and 300 mg/dl scores on the commercially available SST test. However, all other comparisons between crias with different scores revealed significant differences. Sensitivity and specificity ranged between 0 and 1, depending on the test and endpoint selected. CONCLUSIONS AND CLINICAL RELEVANCE The commercially available SST test and determination of serum total protein and globulin concentrations are suitable methods for assessing passive transfer status in llama and alpaca crias.
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Affiliation(s)
- D M Weaver
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia 65211, USA
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Gorzelle BM, Nagy JK, Oxenoid K, Lonzer WL, Cafiso DS, Sanders CR. Reconstitutive refolding of diacylglycerol kinase, an integral membrane protein. Biochemistry 1999; 38:16373-82. [PMID: 10587463 DOI: 10.1021/bi991292n] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
While the formation of kinetically trapped misfolded structural states by membrane proteins is related to a number of diseases, relatively few studies of misfolded membrane proteins in their purified state have been carried out and few methods for refolding such proteins have been reported. In this paper, misfolding of the trimeric integral membrane protein diacylglycerol kinase (DAGK) is documented and a method for refolding the protein is presented; 65 single-cysteine mutants of DAGK were examined. A majority were found to have lower-than-expected activities when purified into micellar solutions, with additional losses in activity often being observed following membrane reconstitution. A variety of evidence indicates that the low activities observed for most of these mutants results from kinetically based misfolding of the protein, with misfolding often being manifested by the formation of aberrant oligomeric states. A method referred to as "reconstitutive refolding" for correcting misfolded DAGK is presented. This method is based upon reconstituting DAGK into multilamellar POPC vesicles by dialyzing the detergent dodecylphosphocholine out of mixed micellar mixtures. For 55 of the 65 mutants tested, there was a gain of DAGK activity during reconstitutive refolding. In 33 of these cases, the gain in activity was greater than 2-fold. The refolding results for cysteine replacement mutants at DAGK sites known to be highly conserved provide teleological insight into whether sites are conserved, because they are critical for catalysis, for maintenance of the proper folding pathway, or for some other reason.
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Affiliation(s)
- B M Gorzelle
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4970, USA
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Glaze LE, Davis W, Floyd DM, Graham CR, Nagy JK, Olson RE, Palau J, Spurlock LF, Sumner WA, VanVelzen WT. Extraction of Light Filth from Oriental Fish Products Containing Spice: Collaborative Study. J AOAC Int 1993. [DOI: 10.1093/jaoac/76.1.44] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
A collaborative study was conducted to validate a new method for the extraction of light filth from oriental fish products containing spice. A100 g test portion is digested by boiling in a mixture of HCI, Igepal DM-710, and CO-730. Light filth is isolated by wetsieving on a No. 230 plain-weave sieve with Tergitol, deaeration boiling in 40% isopropanol, and extracting with mineral oil-heptane (85 + 15) and 40% isopropanol in a Wildman trap flask. Three spiking levels for rat hairs and insect fragments were used in the study. For rat hairs, recoveries at the low, medium, and high levels averaged 80.0,71.6, and 88.0%, respectively. Recoveries of insect fragments for low, medium, and high levels averaged 87.8,83.7, and 89.4%, respectively. The method was adopted first action by AOAC International.
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Affiliation(s)
- Larry E Glaze
- U.S. Food and Drug Administration, Division of Microbiology, Washington, DC 20204
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