27 results on '"Movahed, N."'
Search Results
2. Effect of post-veraison source limitation on the accumulation of sugar, anthocyanins and seed tannins in V itis vinifera cv. Sangiovese berries.
- Author
-
Filippetti, I., Movahed, N., Allegro, G., Valentini, G., Pastore, C., Colucci, E., and Intrieri, C.
- Subjects
- *
ANTHOCYANINS , *TANNINS , *VITIS vinifera , *CLIMATE change , *FRUIT ripening , *GRAPES - Abstract
Background and Aims Climate change can alter the synchronous accumulation of sugar and other main berry compounds during ripening. The aim of this study was to determine whether post-veraison trimming could delay sugar accumulation and influence the production of anthocyanins and seed tannins in Sangiovese grapes. Methods and Results Shoots were trimmed in 2009, 2010 and 2011 when the berry total soluble solids ( TSS) reached 15-17° Brix, leaving eight nodes on each main shoot. The accumulation of TSS, anthocyanins and seed tannins was measured during ripening, and yield parameters were recorded at harvest. Grapes from trimmed vines contained a lower TSS in 2009 and 2010, but there was no impact on the concentration of anthocyanins and seed tannins. In 2011, leaf area limitation was insufficient to reduce TSS accumulation, because yield constraints were observed and the leaf area/yield ratio was within the optimal range. Conclusions The lower rate of TSS accumulation in berries had no impact on the concentration of anthocyanins and seed tannins, suggesting that this approach could produce grapes with a lower TSS at harvest or delay harvest. In low-vigour vines suffering from water deficit, the post-veraison trimming repeated over the years could reduce yield, which may be responsible for the lack of TSS reduction compared with that of control vines. Significance of the Study Our study provides insight into the relationship between TSS accumulation and the production of anthocyanins and seed tannins in the berry in response to post-veraison leaf area reduction. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
3. Phenolic contents and genome-wide expression profiling of grapevine berries (Vitis vinifera L. ‘Sangiovese’) ripened under two different temperature regimes
- Author
-
S. Dal Santo, Gabriele Valentini, Chiara Pastore, Giovanni Battista Tornielli, Gianluca Allegro, Ilaria Filippetti, Sara Zenoni, Nooshin Movahed, Dondini L.,Tartarini S.,Laurens F.,Nybom H., Pastore, C., Movahed, N., Allegro, G., Valentini, G., Zenoni, S., Dal Santo, S., Tornielli, G.B., and Filippetti, I.
- Subjects
0106 biological sciences ,0301 basic medicine ,Anthocyanin ,Titratable acid ,Berry ,Phenolic content ,Heat stre ,Horticulture ,01 natural sciences ,Veraison ,03 medical and health sciences ,chemistry.chemical_compound ,Flavonols ,Climate change ,Sugar ,Grapevine, Phenolic content, High Temperature ,chemistry.chemical_classification ,High Temperature ,Chemistry ,food and beverages ,Ripening ,030104 developmental biology ,Grapevine ,Viticulture ,010606 plant biology & botany - Abstract
High summer temperatures are among the environmental factors that pose serious threats to viticulture in the present and future scenarios of global climate change. Such extremes are expected to affect different aspects of grapevine biology and metabolism. In this work, we studied the effects of two different temperature regimes, on the evolution of main berry compositional parameters and on grapevine genome-wide expression during ripening. Vitis vinifera 'Sangiovese' potted vines were grown, from véraison to harvest, in two air-conditioned greenhouses with high temperature (HT) and low temperature (LT) regimes characterized by 26 and 21°C as average air daily temperature. We determined berry soluble solids, pH, titratable acidity and phenolic compounds as anthocyanins and flavonols during the ripening process. The results indicated that HT regime did not increase sugar accumulation at harvest but contributed to a total acidity reduction. Conversely, changes in growing temperatures greatly impact on grape phenolic composition as the anthocyanin and flavonol contents resulted strongly reduced in HT compared to LT regime. We applied a clustering analysis approach to the obtained genome-wide microarray data to identify those transcripts with a different transcriptional profile when berries were ripened under HT or LT conditions. We found many differential transcripts involved in heat stress response, many stilbene synthase gene family members, and some other transcripts that corroborate our biochemical results.
- Published
- 2017
4. Biochemical approaches to study the effects of temperature on grape composition in cv. Sangiovese (Vitis vinifera L.)
- Author
-
MOVAHED, NOOSHIN, FILIPPETTI, ILARIA, MASIA, ANDREA, CELLINI, ANTONIO, PASTORE, CHIARA, VALENTINI, GABRIELE, ALLEGRO, GIANLUCA, MOVAHED N., FILIPPETTI I., MASIA A., CELLINI A., PASTORE C., VALENTINI G., and ALLEGRO G.
- Subjects
HIGH TEMPERATURE ,POD ,ANTHOCYANINS ,grape - Abstract
High temperatures during ripening, especially after veraison, can affect berry composition in wine grapes. In particular, skin anthocyanin accumulation in black varieties can be negatively influenced. The aim of the present research is to evaluate the effects of high temperatures on flavonoids biosynthesis and the mechanisms responsible for low anthocyanin content, often verified in berries ripened in conditions of elevated temperatures. The study was conducted on potted uniform plants of Sangiovese which were kept in two plastic tunnels, from veraison to harvest, with different temperature conditions. In the first one, the berry temperature was maintained below 30o C during ripening (Low Temperature/LT) and in the second tunnel, the temperature was similar to the field conditions (the average and the maximum of berry temperature during ripening were about 25oC and 40oC respectively, High Temperature/HT). Results indicated that no significant differences have been found in total soluble solids (oBrix), pH and titratable acidity concentrations in HT berries as compared to LT; however a tendency to a higher sugar level has been recorded during ripening in the former. In HT the concentration of total anthocyanin of berry skin was significantly lower than in LT. Among the different anthocyanins, malvidin-3-glucoside seems to be less sensitive to high temperature during ripening. PAL activity in the both LT and HT berries increased gradually after veraison, but was significantly lower in HT plants. Using delphinidin and cyanidin as substrates, the activity of UFGT was also strongly reduced in HT plants compared to the LT ones. Independently from thermic conditions, UFGT activity was higher for cyanidin respect to delphinidin and POD activity strongly increased in HT. In conclusion in cv. Sangiovese the interactive effects induced by the reduction of UFGT and PAL and the increase of POD activities may be considered responsible of the lower anthocyanin concentration recorded in HT treatment.
- Published
- 2011
5. Effects of late-season source limitation induced by trimming and antitranspirants canopy sprays on grape composition during ripening in Vitis vinifera cv. Sangiovese
- Author
-
FILIPPETTI, ILARIA, MOVAHED, NOOSHIN, PASTORE, CHIARA, VALENTINI, GABRIELE, INTRIERI, CESARE, ALLEGRO, GIANLUCA, FILIPPETTI I., ALLEGRO G., MOVAHED N., PASTORE C., VALENTINI G., and INTRIERI C.
- Subjects
antitranspirant ,sugar accumulation ,food and beverages ,seed and skin tannins ,anthocyanin ,trimming - Abstract
The global warming and the general improvement of vineyard management techniques over the last fifty years appear to have upgraded the quality of wine worldwide. Besides, in some wine regions where heat summations largely exceed technological requirements for the grown varieties, grapes showed at harvest a too high level of sugar and subsequent wine alcohol excess, low acidity, alteration of aroma composition and, in black varieties, unbalanced phenolic ripening with insufficient berry skin colour. The final aim of the research is to test the effects of post veraison trimming or anti-transpirant spray on sugar accumulation rate and berry phenolic compounds evolution during ripening. This trial was conducted in 2009 and 2010 on Sangiovese (V. vinifera L.) vines trained to Free Cordon trellis system. Three treatments were compared: non-trimmed control (C); shoot trimming, 1 week after full veraison (TRIMM ); anti-transpirant Pinolene sprayed at 2% concentration, 1 week after full veraison (PIN). Measurements on leaf gas exchange showed that Pinolene spray reduced photosynthetic activity on laterals leaves compared to control ones since the day of spray and up to three-four weeks later. After shoot trimming, the total leaf area of TRIMM vines was reduced at about 40 % of the control. Yield per vine was unaffected by both treatments while both treatments showed in 2009 an higher effect in reducing sugars accumulation rate during ripening compared to 2010. In particular PIN treatments was less effective in 2010, while TRIMM effect, although little, was maintained also in the second year. Despite the differences in sugar accumulation, acidity, pH and anthocyanins concentration during ripening were not significantly affected by treatments. The results showed a quite interesting perspective about canopy management techniques, since trimming or Pinolene spray, slowed down sugars accumulation, giving rise to an improved synchrony between technological and phenolic ripening. The results demonstrate the potential of the news canopy management techniques to upgrade the enological grape quality in face to the global climate warming.
- Published
- 2011
6. Noise Exposure Assessment in Construction Equipment Operators in Tehran, Iran.
- Author
-
Movahed N and Ravanshadnia M
- Subjects
- Humans, Iran epidemiology, Noise, Occupational adverse effects, Noise, Occupational prevention & control, Occupational Diseases, Occupational Exposure adverse effects, Occupational Exposure prevention & control
- Abstract
Occupational hearing loss is a common complication among construction workers, especially those working with heavy machinery and construction equipment. This research measured the noise that construction operators are exposed to, and proves that most of the construction equipment operators that we studied have a potential risk of hearing impairment. We examined 22 types of construction machinery that are commonly used in various stages of construction projects in Tehran (demolition, excavation, and execution). The noise that construction operators were exposed to was measured with a dosimeter during 8 working hours, and the Time-Weighted Average (TWA) was calculated for each operator according to OSHA standards. Finally, a suitable hearing protection device (HPD) was suggested. The results indicated that the operators of D8N (opened-cab) and CAT D8L SA (closed-cab) bulldozers were exposed to more noise than other operators in this study. Hand-saw, Caterpillar 943, and Komatsu 470 loader operators were also exposed to significant noise levels. Other operators, such as drivers of older Benz and Volvo trucks, the Backhoe HLB95, the Soosan mobile crane, and the Bobcat were also exposed to heavy noise that put them at risk of occupational hearing loss.
- Published
- 2022
- Full Text
- View/download PDF
7. Indole-3-glycerolphosphate synthase, a branchpoint for the biosynthesis of tryptophan, indole, and benzoxazinoids in maize.
- Author
-
Richter A, Powell AF, Mirzaei M, Wang LJ, Movahed N, Miller JK, Piñeros MA, and Jander G
- Subjects
- Indole-3-Glycerol-Phosphate Synthase genetics, Benzoxazines metabolism, Indole-3-Glycerol-Phosphate Synthase metabolism, Indoles metabolism, Tryptophan metabolism, Zea mays metabolism
- Abstract
The maize (Zea mays) genome encodes three indole-3-glycerolphosphate synthase enzymes (IGPS1, 2, and 3) catalyzing the conversion of 1-(2-carboxyphenylamino)-l-deoxyribulose-5-phosphate to indole-3-glycerolphosphate. Three further maize enzymes (BX1, benzoxazinoneless 1; TSA, tryptophan synthase alpha subunit; and IGL, indole glycerolphosphate lyase) convert indole-3-glycerolphosphate to indole, which is released as a volatile defense signaling compound and also serves as a precursor for the biosynthesis of tryptophan and defense-related benzoxazinoids. Phylogenetic analyses showed that IGPS2 is similar to enzymes found in both monocots and dicots, whereas maize IGPS1 and IGPS3 are in monocot-specific clades. Fusions of yellow fluorescent protein with maize IGPS enzymes and indole-3-glycerolphosphate lyases were all localized in chloroplasts. In bimolecular fluorescence complementation assays, IGPS1 interacted strongly with BX1 and IGL, IGPS2 interacted primarily with TSA, and IGPS3 interacted equally with all three indole-3-glycerolphosphate lyases. Whereas IGPS1 and IGPS3 expression was induced by insect feeding, IGPS2 expression was not. Transposon insertions in IGPS1 and IGPS3 reduced the abundance of both benzoxazinoids and free indole. Spodoptera exigua (beet armyworm) larvae show improved growth on igps1 mutant maize plants. Together, these results suggest that IGPS1 and IGPS3 function mainly in the biosynthesis of defensive metabolites, whereas IGPS2 may be involved in the biosynthesis of tryptophan. This metabolic channeling is similar to, though less exclusive than, that proposed for the three maize indole-3-glycerolphosphate lyases., (© 2021 Society for Experimental Biology and John Wiley & Sons Ltd.)
- Published
- 2021
- Full Text
- View/download PDF
8. Setaria viridis chlorotic and seedling-lethal mutants define critical functions for chloroplast gene expression.
- Author
-
Feiz L, Strickler SR, van Eck J, Mao L, Movahed N, Taylor C, Gourabathini P, Fei Z, and Stern DB
- Subjects
- Arabidopsis genetics, Arabidopsis physiology, Chloroplasts metabolism, Isoenzymes, Mutation, Phenotype, Photosynthesis genetics, Plant Proteins genetics, Polyribonucleotide Nucleotidyltransferase genetics, Polyribonucleotide Nucleotidyltransferase metabolism, RNA Editing, RNA, Chloroplast genetics, Ribosomal Proteins genetics, Ribosomal Proteins metabolism, Seedlings genetics, Seedlings physiology, Sequence Analysis, RNA, Setaria Plant physiology, Chloroplasts genetics, Gene Expression Regulation, Plant genetics, Plant Proteins metabolism, Setaria Plant genetics
- Abstract
Deep insights into chloroplast biogenesis have been obtained by mutant analysis; however, in C
4 plants a relevant mutant collection has only been developed and exploited for maize. Here, we report the initial characterization of an ethyl methyl sulfonate-induced mutant population for the C4 model Setaria viridis. Approximately 1000 M2 families were screened for the segregation of pale-green seedlings in the M3 generation, and a subset of these was identified to be deficient in post-transcriptional steps of chloroplast gene expression. Causative mutations were identified for three lines using deep sequencing-based bulked segregant analysis, and in one case confirmed by transgenic complementation. Using chloroplast RNA-sequencing and other molecular assays, we describe phenotypes of mutants deficient in PSRP7, a plastid-specific ribosomal protein, OTP86, an RNA editing factor, and cpPNP, the chloroplast isozyme of polynucleotide phosphorylase. The psrp mutant is globally defective in chloroplast translation, and has varying deficiencies in the accumulation of chloroplast-encoded proteins. The otp86 mutant, like its Arabidopsis counterpart, is specifically defective in editing of the rps14 mRNA; however, the conditional pale-green mutant phenotype contrasts with the normal growth of the Arabidopsis mutant. The pnp mutant exhibited multiple defects in 3' end maturation as well as other qualitative changes in the chloroplast RNA population. Overall, our collection opens the door to global analysis of photosynthesis and early seedling development in an emerging C4 model., (© 2020 Society for Experimental Biology and John Wiley & Sons Ltd.)- Published
- 2020
- Full Text
- View/download PDF
9. LUNAPARK Is an E3 Ligase That Mediates Degradation of ROOT HAIR DEFECTIVE3 to Maintain a Tubular ER Network in Arabidopsis.
- Author
-
Sun J, Movahed N, and Zheng H
- Subjects
- Arabidopsis cytology, Arabidopsis genetics, Arabidopsis Proteins genetics, GTP-Binding Proteins genetics, Microtubules metabolism, Mutation, Plant Cells metabolism, Plants, Genetically Modified, Protein Interaction Maps, Ubiquitination, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Endoplasmic Reticulum metabolism, GTP-Binding Proteins metabolism
- Abstract
ROOT HAIR DEFECTIVE3 (RHD3) is an atlastin GTPase involved in homotypic fusion of endoplasmic reticulum (ER) tubules in the formation of the interconnected ER network. Because excessive fusion of ER tubules will lead to the formation of sheet-like ER, the action of atlastin GTPases must be tightly regulated. We show here that RHD3 physically interacts with two Arabidopsis ( Arabidopsis thaliana ) LUNAPARK proteins, LNP1 and LNP2, at three-way junctions of the ER, the sites where different ER tubules fuse. Recruited by RHD3 to newly formed three-way junctions, LNPs act negatively with RHD3 to stabilize the nascent three-way junctions of the ER. Without this LNP-mediated stabilization, in Arabidopsis lnp1-1 lnp2-1 mutant cells, the ER becomes a dense tubular network. Interestingly, in lnp1-1 lnp2-1 mutant cells, the expression level of RHD3 is higher than that in wild-type plants. RHD3 is degraded more slowly in the absence of LNPs as well as in the presence of MG132 and concanamycin A. However, in the presence of LNPs, the degradation of RHD3 is promoted. We have provided in vitro evidence that Arabidopsis LNPs have E3 ubiquitin ligase activity and that LNP1 can directly ubiquitinate RHD3. Our data show that after ER fusion is completed, RHD3 is degraded by LNPs so that nascent three-way junctions can be stabilized and a tubular ER network can be maintained., (© 2020 American Society of Plant Biologists. All rights reserved.)
- Published
- 2020
- Full Text
- View/download PDF
10. Turnip Mosaic Virus Components Are Released into the Extracellular Space by Vesicles in Infected Leaves.
- Author
-
Movahed N, Cabanillas DG, Wan J, Vali H, Laliberté JF, and Zheng H
- Subjects
- Arabidopsis metabolism, Arabidopsis virology, Endoplasmic Reticulum metabolism, Endoplasmic Reticulum virology, Extracellular Space virology, Host-Pathogen Interactions, Microscopy, Electron, Scanning, Microscopy, Electron, Transmission, Multivesicular Bodies ultrastructure, Multivesicular Bodies virology, Plant Leaves virology, Potyvirus genetics, Potyvirus physiology, Proteomics methods, RNA, Viral genetics, RNA, Viral metabolism, Nicotiana metabolism, Nicotiana virology, Viral Proteins metabolism, Virus Replication genetics, Extracellular Space metabolism, Multivesicular Bodies metabolism, Plant Leaves metabolism, Potyvirus metabolism
- Abstract
Turnip mosaic virus (TuMV) reorganizes the endomembrane system of the infected cell to generate endoplasmic-reticulum-derived motile vesicles containing viral replication complexes. The membrane-associated viral protein 6K
2 plays a key role in the formation of these vesicles. Using confocal microscopy, we observed that this viral protein, a marker for viral replication complexes, localized in the extracellular space of infected Nicotiana benthamiana leaves. Previously, we showed that viral RNA is associated with multivesicular bodies (MVBs). Here, using transmission electron microscopy, we observed the proliferation of MVBs during infection and their fusion with the plasma membrane that resulted in the release of their intraluminal vesicles in the extracellular space. Immunogold labeling with a monoclonal antibody that recognizes double-stranded RNA indicated that the released vesicles contained viral RNA. Focused ion beam-extreme high-resolution scanning electron microscopy was used to generate a three-dimensional image that showed extracellular vesicles in the cell wall. The presence of TuMV proteins in the extracellular space was confirmed by proteomic analysis of purified extracellular vesicles from N benthamiana and Arabidopsis ( Arabidopsis thaliana ). Host proteins involved in biotic defense and in interorganelle vesicular exchange were also detected. The association of extracellular vesicles with viral proteins and RNA emphasizes the implication of the plant extracellular space in viral infection., (© 2019 American Society of Plant Biologists. All Rights Reserved.)- Published
- 2019
- Full Text
- View/download PDF
11. A Host ER Fusogen Is Recruited by Turnip Mosaic Virus for Maturation of Viral Replication Vesicles.
- Author
-
Movahed N, Sun J, Vali H, Laliberté JF, and Zheng H
- Subjects
- Arabidopsis genetics, Arabidopsis virology, Arabidopsis Proteins genetics, Endoplasmic Reticulum virology, GTP-Binding Proteins genetics, Golgi Apparatus metabolism, Microorganisms, Genetically-Modified, Microscopy, Electron, Transmission, Microscopy, Fluorescence, Mutation, Plant Cells virology, Plants, Genetically Modified, Nicotiana genetics, Nicotiana virology, Viral Proteins genetics, Viral Proteins metabolism, Arabidopsis Proteins metabolism, GTP-Binding Proteins metabolism, Host-Pathogen Interactions physiology, Potyvirus physiology, Virus Replication physiology
- Abstract
Like other positive-strand RNA viruses, the Turnip mosaic virus (TuMV) infection leads to the formation of viral vesicles at the endoplasmic reticulum (ER). Once released from the ER, the viral vesicles mature intracellularly and then move intercellularly. While it is known that the membrane-associated viral protein 6K2 plays a role in the process, the contribution of host proteins has been poorly defined. In this article, we show that 6K2 interacts with RHD3, an ER fusogen required for efficient ER fusion. When RHD3 is mutated, a delay in the development of TuMV infection is observed. We found that the replication of TuMV and the cell-to-cell movement of its replication vesicles are impaired in rhd3 This defect can be tracked to a delayed maturation of the viral vesicles from the replication incompetent to the competent state. Furthermore, 6K2 can relocate RHD3 from the ER to viral vesicles. However, a Golgi-localized mutated 6K2
GV is unable to interact and relocate RHD3 to viral vesicles. We conclude that the maturation of TuMV replication vesicles requires RHD3 for efficient viral replication and movement., (© 2019 American Society of Plant Biologists. All Rights Reserved.)- Published
- 2019
- Full Text
- View/download PDF
12. Turnip Mosaic Virus Uses the SNARE Protein VTI11 in an Unconventional Route for Replication Vesicle Trafficking.
- Author
-
Cabanillas DG, Jiang J, Movahed N, Germain H, Yamaji Y, Zheng H, and Laliberté JF
- Subjects
- Amino Acid Motifs, Arabidopsis genetics, Arabidopsis Proteins genetics, Brefeldin A pharmacology, Endoplasmic Reticulum metabolism, Endoplasmic Reticulum virology, Golgi Apparatus metabolism, Golgi Apparatus virology, Mutagenesis, Site-Directed, Plant Leaves virology, Plants, Genetically Modified, Potyvirus pathogenicity, Qb-SNARE Proteins genetics, SNARE Proteins genetics, SNARE Proteins metabolism, Synaptotagmins metabolism, Nicotiana drug effects, Nicotiana genetics, Vesicular Transport Proteins chemistry, Vesicular Transport Proteins genetics, Vesicular Transport Proteins metabolism, Viral Proteins chemistry, Viral Proteins genetics, Viral Proteins metabolism, Virus Replication physiology, Arabidopsis virology, Arabidopsis Proteins metabolism, Host-Pathogen Interactions physiology, Potyvirus physiology, Qb-SNARE Proteins metabolism, Nicotiana virology
- Abstract
Infection of plant cells by RNA viruses leads to the generation of organelle-like subcellular structures that contain the viral replication complex. During Turnip mosaic virus (TuMV) infection of Nicotiana benthamiana , the viral membrane protein 6K
2 plays a key role in the release of motile replication vesicles from the host endoplasmic reticulum (ER). Here, we demonstrate that 6K2 contains a GxxxG motif within its predicted transmembrane domain that is vital for TuMV infection. Replacement of the Gly with Val within this motif inhibited virus production, and this was due to a relocation of the viral protein to the Golgi apparatus and the plasma membrane. This indicated that passage of 6K2 through the Golgi apparatus is a dead-end avenue for virus infection. Impairing the fusion of transport vesicles between the ER and the Golgi apparatus by overexpression of the SNARE Sec22 protein resulted in enhanced intercellular virus movement. Likewise, expression of nonfunctional, Golgi-located synaptotagmin during infection enhanced TuMV intercellular movement. 6K2 copurified with VTI11, a prevacuolar compartment SNARE protein. An Arabidopsis thaliana vti11 mutant was completely resistant to TuMV infection. We conclude that TuMV replication vesicles bypass the Golgi apparatus and take an unconventional pathway that may involve prevacuolar compartments/multivesicular bodies for virus infection., (© 2018 American Society of Plant Biologists. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
13. Cylindrical Inclusion Protein of Turnip Mosaic Virus Serves as a Docking Point for the Intercellular Movement of Viral Replication Vesicles.
- Author
-
Movahed N, Patarroyo C, Sun J, Vali H, Laliberté JF, and Zheng H
- Subjects
- Plant Viral Movement Proteins, Nicotiana physiology, Nicotiana virology, Viral Proteins genetics, Gene Expression Regulation, Viral physiology, Potyvirus physiology, Viral Proteins metabolism, Virus Replication physiology
- Abstract
Plant viruses move from the initially infected cell to adjacent cells through plasmodesmata (PDs). To do so, viruses encode dedicated protein(s) that facilitate this process. How viral proteins act together to support the intercellular movement of viruses is poorly defined. Here, by using an infection-free intercellular vesicle movement assay, we investigate the action of CI (cylindrical inclusion) and P3N-PIPO (amino-terminal half of P3 fused to Pretty Interesting Potyviridae open reading frame), the two PD-localized potyviral proteins encoded by Turnip mosaic virus (TuMV), in the intercellular movement of the viral replication vesicles. We provide evidence that CI and P3N-PIPO are sufficient to support the PD targeting and intercellular movement of TuMV replication vesicles induced by 6K2, a viral protein responsible for the generation of replication vesicles. 6K2 interacts with CI but not P3N-PIPO. When this interaction is impaired, the intercellular movement of TuMV replication vesicles is inhibited. Furthermore, in transmission electron microscopy, vesicular structures are observed in connection with the cylindrical inclusion bodies at structurally modified PDs in cells coexpressing 6K2, CI, and P3N-PIPO. CI is directed to PDs through its interaction with P3N-PIPO. We hypothesize that CI serves as a docking point for PD targeting and the intercellular movement of TuMV replication vesicles. This work contributes to a better understanding of the roles of different viral proteins in coordinating the intercellular movement of viral replication vesicles., (© 2017 American Society of Plant Biologists. All Rights Reserved.)
- Published
- 2017
- Full Text
- View/download PDF
14. Whole Plant Temperature Manipulation Affects Flavonoid Metabolism and the Transcriptome of Grapevine Berries.
- Author
-
Pastore C, Dal Santo S, Zenoni S, Movahed N, Allegro G, Valentini G, Filippetti I, and Tornielli GB
- Abstract
Among environmental factors, temperature is the one that poses serious threats to viticulture in the present and future scenarios of global climate change. In this work, we evaluated the effects on berry ripening of two thermal regimes, imposed from veraison to harvest. Potted vines were grown in two air-conditioned greenhouses with High Temperature (HT) and Low Temperature (LT) regimes characterized by 26 and 21°C as average and 42 and 35°C as maximum air daily temperature, respectively. We conducted analyses of the main berry compositional parameters, berry skin flavonoids and berry skin transcriptome on HT and LT berries sampled during ripening. The two thermal conditions strongly differentiated the berries. HT regime increased sugar accumulation at the beginning of ripening, but not at harvest, when HT treatment contributed to a slight total acidity reduction and pH increase. Conversely, growing temperatures greatly impacted on anthocyanin and flavonol concentrations, which resulted as strongly reduced, while no effects were found on skin tannins accumulation. Berry transcriptome was analyzed with several approaches in order to identify genes with different expression profile in berries ripened under HT or LT conditions. The analysis of whole transcriptome showed that the main differences emerging from this approach appeared to be more due to a shift in the ripening process, rather than to a strong rearrangement at transcriptional level, revealing that the LT temperature regime could delay berry ripening, at least in the early stages. Moreover, the results of the in-depth screening of genes differentially expressed in HT and LT did not highlight differences in the expression of transcripts involved in the biosynthesis of flavonoids (with the exception of PAL and STS) despite the enzymatic activities of PALs and UFGT being significantly higher in LT than HT. This suggests only a partial correlation between molecular and biochemical data in our conditions and the putative existence of post-transcriptional and post-translational mechanisms playing significant roles in the regulation of flavonoid metabolic pathways and in particular of anthocyanins.
- Published
- 2017
- Full Text
- View/download PDF
15. The grapevine VviPrx31 peroxidase as a candidate gene involved in anthocyanin degradation in ripening berries under high temperature.
- Author
-
Movahed N, Pastore C, Cellini A, Allegro G, Valentini G, Zenoni S, Cavallini E, D'Incà E, Tornielli GB, and Filippetti I
- Subjects
- Flowers metabolism, Fruit enzymology, Gene Expression Regulation, Plant, Glucosyltransferases genetics, Glucosyltransferases metabolism, Heat-Shock Response genetics, Hydrogen-Ion Concentration, Peroxidases metabolism, Petunia genetics, Phylogeny, Plant Proteins genetics, Plant Proteins metabolism, Plants, Genetically Modified, RNA, Messenger genetics, RNA, Messenger metabolism, Solubility, Anthocyanins metabolism, Fruit genetics, Genes, Plant, Genetic Association Studies, Hot Temperature, Peroxidases genetics, Vitis enzymology, Vitis genetics
- Abstract
Anthocyanin levels decline in some red grape berry varieties ripened under high-temperature conditions, but the underlying mechanism is not yet clear. Here we studied the effects of two different temperature regimes, representing actual Sangiovese (Vitis vinifera L.) viticulture regions, on the accumulation of mRNAs and enzymes controlling berry skin anthocyanins. Potted uniform plants of Sangiovese were kept from veraison to harvest, in two plastic greenhouses with different temperature conditions. The low temperature (LT) conditions featured average and maximum daily air temperatures of 20 and 29 °C, respectively, whereas the corresponding high temperature (HT) conditions were 22 and 36 °C, respectively. The anthocyanin concentration at harvest was much lower in HT berries than LT berries although their profile was similar under both conditions. Under HT conditions, the biosynthesis of anthocyanins was suppressed at both the transcriptional and enzymatic levels, but peroxidase activity was higher. This suggests that the low anthocyanin content of HT berries reflects the combined impact of reduced biosynthesis and increased degradation, particularly the direct role of peroxidases in anthocyanin catabolism. Overexpression of VviPrx31 decreased anthocyanin contents in Petunia hybrida petals under heat stress condition. These data suggest that high temperature can stimulate peroxidase activity thus anthocyanin degradation in ripening grape berries.
- Published
- 2016
- Full Text
- View/download PDF
16. Universal buffers for use in biochemistry and biophysical experiments.
- Author
-
Brooke D, Movahed N, and Bothner B
- Abstract
The use of buffers that mimic biological solutions is a foundation of biochemical and biophysical studies. However, buffering agents have both specific and nonspecific interactions with proteins. Buffer molecules can induce changes in conformational equilibria, dynamic behavior, and catalytic properties merely by their presence in solution. This effect is of concern because many of the standard experiments used to investigate protein structure and function involve changing solution conditions such as pH and/or temperature. In experiments in which pH is varied, it is common practice to switch buffering agents so that the pH is within the working range of the weak acid and conjugate base. If multiple buffers are used, it is not always possible to decouple buffer induced change from pH or temperature induced change. We have developed a series of mixed biological buffers for protein analysis that can be used across a broad pH range, are compatible with biologically relevant metal ions, and avoid complications that may arise from changing the small molecule composition of buffers when pH is used as an experimental variable., Competing Interests: Conflict of Interest All authors declare no conflicts of interest in this paper.
- Published
- 2015
- Full Text
- View/download PDF
17. Fluorometric Estimation of Viral Thermal Stability.
- Author
-
Rayaprolu V, Kruse S, Kant R, Movahed N, Brooke D, and Bothner B
- Abstract
Differential Scanning Fluorimetry (DSF) is a rapid, economical, and a straightforward technique for estimating the thermal stability of proteins. The principle involves the binding of a fluorescent dye to thermally exposed hydrophobic pockets of a protein. The dyes used in this technique are highly fluorescent in a non-polar environment and are quenched when exposed to aqueous solution. The change in fluorescence can be used to follow unfolding of proteins induced by temperature, pH, or chaotropic agents. The method is well characterized for monomeric proteins. Here, we extend the application to supramolecular protein and nucleo-protein complexes using virus particles as an example. SYPRO-orange™ dye is the dye of choice because it is matched for use with q-PCR instruments and the fluorescence response is stable across a wide range of pH and temperatures. Advantages of this technique over standard biophysical methods include the ability for high-throughput screening of biological and technical replicates and the high sensitivity.
- Published
- 2014
- Full Text
- View/download PDF
18. Comparison of the incipient lesion enamel fluoride uptake from various prescription and OTC fluoride toothpastes and gels.
- Author
-
Schemehorn BR, DiMarino JC, and Movahed N
- Subjects
- Animals, Caseins metabolism, Cattle, In Vitro Techniques, Incisor, Calcium Phosphates metabolism, Dental Enamel drug effects, Fluorides metabolism, Gels chemistry, Tin Fluorides metabolism, Toothpastes chemistry
- Abstract
Objective: The objective of this in vitro study was to compare the fluoride uptake into incipient enamel lesions of a novel 970 ppm F- ion SnF2 over-the-counter (OTC) gel (Enamelon Preventive Treatment Gel) and a novel 1150 ppm F- ion OTC toothpaste (Enamelon), each delivering amorphous calcium phosphate (ACP), to the uptake from two different prescription strength, 5000 ppm F- ion dentifrices containing tri-calcium phosphate (TCP) and a prescription 900 ppm F- ion paste containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)., Methods: The test procedure followed method #40 in the US-FDA Anticaries Drug Products for OTC Human Use, Final Monograph testing procedures. Eight sets of twelve incisor enamel cores were mounted in Plexiglas rods and the exposed surfaces were polished. The indigenous fluoride levels of each specimen were determined prior to treatment. The treatments were performed using slurries of a negative control (water) and the following products applied to a set of sound enamel cores: 5000 ppm F- ion, sodium fluoride (NaF) prescription (Rx) dentifrice "A" containing TCP; 5000 ppm F- ion, NaF Rx dentifrice "B" containing TCP; 900 ppm F- ion, NaF Rx paste with CPP-ACP; 1150 ppm F- ion, NaF OTC toothpaste; 1150 ppm F- ion, stannous fluoride (SnF2) OTC toothpaste delivering ACP (Enamelon); 1100 ppm F- ion, SnF2 OTC toothpaste; and 970 ppm F- ion, SnF2 OTC gel delivering ACP (Enamelon Preventive Treatment Gel). The twelve specimens of each group were immersed into 25 ml of their assigned slurry with constant stirring (350 rpm) for 30 minutes. Following treatment, one layer of enamel was removed from each specimen and analyzed for fluoride and calcium. The pre-treatment fluoride (indigenous) level of each specimen was subtracted from the post-treatment value to determine the change in enamel fluoride due to the test treatment., Results: The increase in the average fluoride uptake for treated enamel cores was: 10,263 ± 295 ppm for the 970 ppm F- ion, Enamelon Preventive Treatment Gel; 7,016 ± 353 ppm for the 1150 ppm F- ion Enamelon Toothpaste; 4,138 ± 120 ppm for the 5000 ppm F- ion, NaF prescription dentifrice "A" with TCP; 3801 ± 121 ppm for the 5000 ppm F- ion, NaF prescription dentifrice "B" with TCP; 2,647 ± 57 ppm for the 1100 ppm F- ion, SnF2 OTC toothpaste; 1470 ± 40 ppm for the 1150 ppm F- ion, NaF OTC toothpaste; and 316 ± 9 ppm for the 900 ppm F- ion, NaF paste with CPP-ACP. The differences among all the products tested were statistically significant (p < 0.05), except for the two 5000 ppm F- ion products with TCP that were not statistically different from one another, and the 900 ppm F ion, NaF paste with CPP-ACP that was not statistically different from the negative water control., Conclusion: The Enamelon products (970 ppm and 150 ppm F ion, SnF2OTC dentifrices) delivering ACP provide statistically significantly more fluoride to incipient enamel lesions than two prescription strength 5000 ppm F- ion toothpastes containing TCP, the 900 ppm F- ion prescription paste containing CPP-ACP, and the other OTC toothpastes compared in this study.
- Published
- 2014
19. Expanding the paradigm of thiol redox in the thermophilic root of life.
- Author
-
Heinemann J, Hamerly T, Maaty WS, Movahed N, Steffens JD, Reeves BD, Hilmer JK, Therien J, Grieco PA, Peters JW, and Bothner B
- Subjects
- Adaptation, Physiological, Chromatography, Liquid, Cysteine chemistry, Cysteine metabolism, Disulfides metabolism, Electrophoresis, Gel, Two-Dimensional, Glutathione metabolism, Hot Temperature, NADP metabolism, Oxidation-Reduction, Oxidative Stress, Proteins metabolism, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Disulfides chemistry, Glutathione chemistry, Metabolome, Proteins chemistry, Proteome analysis, Sulfolobus solfataricus metabolism
- Abstract
Background: The current paradigm of intracellular redox chemistry maintains that cells establish a reducing environment maintained by a pool of small molecule and protein thiol to protect against oxidative damage. This strategy is conserved in mesophilic organisms from all domains of life, but has been confounded in thermophilic organisms where evidence suggests that intracellular proteins have abundant disulfides., Methods: Chemical labeling and 2-dimensional gel electrophoresis were used to capture disulfide bonding in the proteome of the model thermophile Sulfolobus solfataricus. The redox poise of the metabolome was characterized using both chemical labeling and untargeted liquid chromatography mass spectrometry. Gene annotation was undertaken using support vector machine based pattern recognition., Results: Proteomic analysis indicated the intracellular protein thiol of S. solfataricus was primarily in the disulfide form. Metabolic characterization revealed a lack of reduced small molecule thiol. Glutathione was found primarily in the oxidized state (GSSG), at relatively low concentration. Combined with genetic analysis, this evidence shows that pathways for synthesis of glutathione do exist in the archaeal domain., Conclusions: In observed thermophilic organisms, thiol abundance and redox poise suggest that this system is not directly utilized for protection against oxidative damage. Instead, a more oxidized intracellular environment promotes disulfide bonding, a critical adaptation for protein thermostability., General Significance: Based on the placement of thermophilic archaea close to the last universal common ancestor in rRNA phylogenies, we hypothesize that thiol-based redox systems are derived from metabolic pathways originally tasked with promoting protein stability., (© 2013.)
- Published
- 2014
- Full Text
- View/download PDF
20. Comparison of the enamel solubility reduction from Various prescription and OTC fluoride toothpastes and gels.
- Author
-
Schemehorn BR, DiMarino JC, and Movahed N
- Subjects
- Dental Enamel Permeability, Humans, In Vitro Techniques, Molar, Sodium Fluoride chemistry, Tooth Remineralization, Calcium Phosphates pharmacokinetics, Dental Enamel metabolism, Dental Enamel Solubility drug effects, Fluorides pharmacokinetics, Gels chemistry, Sodium Fluoride pharmacokinetics, Toothpastes chemistry
- Abstract
Objective: The purpose of this in vitro study was to determine if a novel 970 ppm F ion SnF2OTC gel (Enamelon Preventive Treatment Gel) and a 1150 ppm F- ion SnF2OTC Enamelon Toothpaste, each delivering amorphous calcium phosphate (ACP), can significantly reduce the effect of an acid challenge to enamel as compared to two prescription (Rx) strength 5000 ppm F- ion (NaF) dentifrices containing tri-calcium phosphate (TCP), and an Rx 900 ppm F- ion (NaF) paste with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). The effect will be determined by measuring the resistance of enamel specimens to an acid challenge before and after treatment with the test dentifrices., Methods: The procedure used in this study was the FDA Test Method #33 for the determination of the effect of different test dentifrices on enamel solubility reduction. Twelve sets of three extracted human teeth were unprotected and etched prior to treatment with 0.1 M lactic acid buffer solution. The amount of phosphate dissolved from the teeth was quantified via measuring the phosphate in the retained lactate buffer solution with phosphorous analysis (pre-treatment phosphorous levels). The teeth sets were then exposed to the following treatments (diluted 1:3 parts in preheated [37 degrees C] distilled water): 5000 ppm F- ion, sodium fluoride (NaF) Rx dentifrice containing TCP; 5000 ppm F- ion, NaF Rx dentifrice; 900 ppm F- ion, NaF Rx paste with CPP-ACP; 1150 ppm F- ion, stannous fluoride (SnF2) OTC toothpaste delivering ACP Enamelon Toothpaste; and 970 ppm F- ion, SnF2 OTC gel delivering ACP (Enamelon Preventive Treatment Gel). The teeth sets were rinsed with distilled water and then exposed to 0.1 M buffered lactic acid solution. The amount of phosphate in the lactic acid buffer was determined for a second time (post-treatment phosphorous levels). The percent of enamel solubility reduction was then computed as the difference between the amount of phosphorous in the pre- and post-treatment lactic acid solutions divided by the amount of phosphorous in the pre-treatment solution, and multiplied by 100., Results: The percent reduction in enamel solubility recorded in this study was as follows: 60.14 ± 0.79 for the Enamelon Toothpaste; 56.91 ± 1.05 for the Enamelon Preventive Treatment Gel; 18.78 ± 3.20 for the 5000 ppm F- ion, NaF prescription dentifrice "A' with TCP; 6.84 ± 1.20 for the 900 ppm F- ion, NaF paste with CPP-ACP; 5.82 ± 3.10 for the 5000 ppm F- ion, NaF prescription dentifrice "B" with TCP; and -5.45 ± 1.86 for the negative control. The differences between all the products tested were statistically significant (p < 0.05), except for the Enamelon products that were not statistically different. The 900 ppm F- ion, NaF paste with CPP-ACP and the 5000 ppm F- ion, NaF toothpaste results were also not statistically different., Conclusion: The Enamelon products (970 ppm and 1150 ppm F- ion, SnF2 OTC dentifrices) delivering ACP were statistically significantly more effective in reducing enamel solubility than two Rx strength 5000 ppm F- ion NaF toothpastes containing TCP and the Rx 900 ppm F- ion NaF paste containing CPP-ACP.
- Published
- 2014
21. Comparative analysis of adeno-associated virus capsid stability and dynamics.
- Author
-
Rayaprolu V, Kruse S, Kant R, Venkatakrishnan B, Movahed N, Brooke D, Lins B, Bennett A, Potter T, McKenna R, Agbandje-McKenna M, and Bothner B
- Subjects
- Calorimetry, Differential Scanning, Capsid metabolism, Capsid ultrastructure, Capsid Proteins chemistry, Capsid Proteins genetics, Capsid Proteins metabolism, Dependovirus classification, Dependovirus genetics, Dependovirus ultrastructure, Genetic Therapy, Genetic Vectors chemistry, Genetic Vectors genetics, Genetic Vectors metabolism, Microscopy, Electron, Protein Stability, Capsid chemistry, Dependovirus chemistry
- Abstract
Icosahedral viral capsids are obligated to perform a thermodynamic balancing act. Capsids must be stable enough to protect the genome until a suitable host cell is encountered yet be poised to bind receptor, initiate cell entry, navigate the cellular milieu, and release their genome in the appropriate replication compartment. In this study, serotypes of adeno-associated virus (AAV), AAV1, AAV2, AAV5, and AAV8, were compared with respect to the physical properties of their capsids that influence thermodynamic stability. Thermal stability measurements using differential scanning fluorimetry, differential scanning calorimetry, and electron microscopy showed that capsid melting temperatures differed by more than 20°C between the least and most stable serotypes, AAV2 and AAV5, respectively. Limited proteolysis and peptide mass mapping of intact particles were used to investigate capsid protein dynamics. Active hot spots mapped to the region surrounding the 3-fold axis of symmetry for all serotypes. Cleavages also mapped to the unique region of VP1 which contains a phospholipase domain, indicating transient exposure on the surface of the capsid. Data on the biophysical properties of the different AAV serotypes are important for understanding cellular trafficking and is critical to their production, storage, and use for gene therapy. The distinct differences reported here provide direction for future studies on entry and vector production.
- Published
- 2013
- Full Text
- View/download PDF
22. Virus assembly and maturation: auto-regulation through allosteric molecular switches.
- Author
-
Domitrovic T, Movahed N, Bothner B, Matsui T, Wang Q, Doerschuk PC, and Johnson JE
- Subjects
- Allosteric Regulation, Animals, Homeostasis, Moths virology, Nodaviridae growth & development, Nodaviridae physiology, Virus Assembly physiology
- Abstract
We generalize the concept of allostery from the traditional non-active-site control of enzymes to virus maturation. Virtually, all animal viruses transition from a procapsid noninfectious state to a mature infectious state. The procapsid contains an encoded chemical program that is executed following an environmental cue. We developed an exceptionally accessible virus system for the study of the activators of maturation and the downstream consequences that result in particle stability and infectivity. Nudaurelia capensis omega virus (NωV) is a T=4 icosahedral virus that undergoes a dramatic maturation in which the 490-Å spherical procapsid condenses to a 400-Å icosahedral-shaped capsid with associated specific auto-proteolysis and stabilization. Employing X-ray crystallography, time-resolved electron cryo-microscopy and hydrogen/deuterium exchange as well as biochemistry, it was possible to define the mechanisms of allosteric communication among the four quasi-equivalent subunits in the icosahedral asymmetric unit. These gene products undergo proteolysis at different rates, dependent on quaternary structure environment, while particle stability is conferred globally following only a few local subunit transitions. We show that there is a close similarity between the concepts of tensegrity (associated with geodesic domes and mechanical engineering) and allostery (associated with biochemical control mechanisms)., (Copyright © 2013 Elsevier Ltd. All rights reserved.)
- Published
- 2013
- Full Text
- View/download PDF
23. Proteomic analysis of Sulfolobus solfataricus during Sulfolobus Turreted Icosahedral Virus infection.
- Author
-
Maaty WS, Selvig K, Ryder S, Tarlykov P, Hilmer JK, Heinemann J, Steffens J, Snyder JC, Ortmann AC, Movahed N, Spicka K, Chetia L, Grieco PA, Dratz EA, Douglas T, Young MJ, and Bothner B
- Subjects
- Amino Acid Sequence, Archaeal Proteins chemistry, Archaeal Proteins metabolism, Archaeal Viruses genetics, Chromatography, Liquid, Electrophoresis, Gel, Two-Dimensional, Host-Pathogen Interactions, Molecular Sequence Data, Sequence Alignment, Sulfolobus solfataricus chemistry, Tandem Mass Spectrometry, Virus Replication, Archaeal Proteins analysis, Archaeal Viruses metabolism, Proteomics methods, Sulfolobus solfataricus metabolism, Sulfolobus solfataricus virology
- Abstract
Where there is life, there are viruses. The impact of viruses on evolution, global nutrient cycling, and disease has driven research on their cellular and molecular biology. Knowledge exists for a wide range of viruses; however, a major exception are viruses with archaeal hosts. Archaeal virus-host systems are of great interest because they have similarities to both eukaryotic and bacterial systems and often live in extreme environments. Here we report the first proteomics-based experiments on archaeal host response to viral infection. Sulfolobus Turreted Icosahedral Virus (STIV) infection of Sulfolobus solfataricus P2 was studied using 1D and 2D differential gel electrophoresis (DIGE) to measure abundance and redox changes. Cysteine reactivity was measured using novel fluorescent zwitterionic chemical probes that, together with abundance changes, suggest that virus and host are both vying for control of redox status in the cells. Proteins from nearly 50% of the predicted viral open reading frames were found along with a new STIV protein with a homologue in STIV2. This study provides insight to features of viral replication novel to the archaea, makes strong connections to well-described mechanisms used by eukaryotic viruses such as ESCRT-III mediated transport, and emphasizes the complementary nature of different omics approaches.
- Published
- 2012
- Full Text
- View/download PDF
24. The nucleotide exchange factor Ric-8A is a chaperone for the conformationally dynamic nucleotide-free state of Gαi1.
- Author
-
Thomas CJ, Briknarová K, Hilmer JK, Movahed N, Bothner B, Sumida JP, Tall GG, and Sprang SR
- Subjects
- Animals, Deuterium Exchange Measurement, Guanine Nucleotide Exchange Factors chemistry, Guanosine 5'-O-(3-Thiotriphosphate) metabolism, Guanosine Diphosphate metabolism, Magnetic Resonance Spectroscopy, Molecular Chaperones chemistry, Nuclear Proteins chemistry, Protein Binding, Protein Denaturation, Protein Stability, Protein Structure, Secondary, Protons, Rats, Thermodynamics, Trypsin metabolism, GTP-Binding Protein alpha Subunits, Gi-Go chemistry, GTP-Binding Protein alpha Subunits, Gi-Go metabolism, Guanine Nucleotide Exchange Factors metabolism, Molecular Chaperones metabolism, Nuclear Proteins metabolism, Nucleotides metabolism
- Abstract
Heterotrimeric G protein α subunits are activated upon exchange of GDP for GTP at the nucleotide binding site of Gα, catalyzed by guanine nucleotide exchange factors (GEFs). In addition to transmembrane G protein-coupled receptors (GPCRs), which act on G protein heterotrimers, members of the family cytosolic proteins typified by mammalian Ric-8A are GEFs for Gi/q/12/13-class Gα subunits. Ric-8A binds to Gα•GDP, resulting in the release of GDP. The Ric-8A complex with nucleotide-free Gαi1 is stable, but dissociates upon binding of GTP to Gαi1. To gain insight into the mechanism of Ric-8A-catalyzed GDP release from Gαi1, experiments were conducted to characterize the physical state of nucleotide-free Gαi1 (hereafter referred to as Gαi1[ ]) in solution, both as a monomeric species, and in the complex with Ric-8A. We found that Ric-8A-bound, nucleotide-free Gαi1 is more accessible to trypsinolysis than Gαi1•GDP, but less so than Gαi1[ ] alone. The TROSY-HSQC spectrum of [(15)N]Gαi1[ ] bound to Ric-8A shows considerable loss of peak intensity relative to that of [(15)N]Gαi1•GDP. Hydrogen-deuterium exchange in Gαi1[ ] bound to Ric-8A is 1.5-fold more extensive than in Gαi1•GDP. Differential scanning calorimetry shows that both Ric-8A and Gαi1•GDP undergo cooperative, irreversible unfolding transitions at 47° and 52°, respectively, while nucleotide-free Gαi1 shows a broad, weak transition near 35°. The unfolding transition for Ric-8A:Gαi1[ ] is complex, with a broad transition that peaks at 50°, suggesting that both Ric-8A and Gαi1[ ] are stabilized within the complex, relative to their respective free states. The C-terminus of Gαi1 is shown to be a critical binding element for Ric-8A, as is also the case for GPCRs, suggesting that the two types of GEF might promote nucleotide exchange by similar mechanisms, by acting as chaperones for the unstable and dynamic nucleotide-free state of Gα.
- Published
- 2011
- Full Text
- View/download PDF
25. Trehalose 6-phosphate phosphatase is required for cell wall integrity and fungal virulence but not trehalose biosynthesis in the human fungal pathogen Aspergillus fumigatus.
- Author
-
Puttikamonkul S, Willger SD, Grahl N, Perfect JR, Movahed N, Bothner B, Park S, Paderu P, Perlin DS, and Cramer RA Jr
- Subjects
- Animals, Aspergillus fumigatus genetics, Aspergillus fumigatus metabolism, Culture Media chemistry, Disease Models, Animal, Invasive Pulmonary Aspergillosis microbiology, Invasive Pulmonary Aspergillosis pathology, Lung pathology, Mice, Mutation, Phosphoric Monoester Hydrolases genetics, Survival Analysis, Virulence, Aspergillus fumigatus enzymology, Aspergillus fumigatus growth & development, Cell Wall metabolism, Phosphoric Monoester Hydrolases metabolism, Trehalose metabolism
- Abstract
The trehalose biosynthesis pathway is critical for virulence in human and plant fungal pathogens. In this study, we tested the hypothesis that trehalose 6-phosphate phosphatase (T6PP) is required for Aspergillus fumigatus virulence. A mutant of the A. fumigatus T6PP, OrlA, displayed severe morphological defects related to asexual reproduction when grown on glucose (1%) minimal media. These defects could be rescued by addition of osmotic stabilizers, reduction in incubation temperature or increase in glucose levels (> 4%). Subsequent examination of the mutant with cell wall perturbing agents revealed a link between cell wall biosynthesis and trehalose 6-phosphate (T6P) levels. As expected, high levels of T6P accumulated in the absence of OrlA resulting in depletion of free inorganic phosphate and inhibition of hexokinase activity. Surprisingly, trehalose production persisted in the absence of OrlA. Further analyses revealed that A. fumigatus contains two trehalose phosphorylases that may be responsible for trehalose production in the absence of OrlA. Despite a normal growth rate under in vitro growth conditions, the orlA mutant was virtually avirulent in two distinct murine models of invasive pulmonary aspergillosis. Our results suggest that further study of this pathway will lead to new insights into regulation of fungal cell wall biosynthesis and virulence., (© 2010 Blackwell Publishing Ltd.)
- Published
- 2010
- Full Text
- View/download PDF
26. Results of the repair of aortic false aneurysm.
- Author
-
Ahmadi SH, Movahed N, Abbasi K, Soltaninia H, Amirzadegan AR, Najafi M, Shirani S, Marzban M, Karimi AA, Mirhoseini SJ, and Sanatkarfar M
- Subjects
- Adult, Aorta metabolism, Cardiopulmonary Bypass, Humans, Middle Aged, Radiography, Thoracic methods, Temperature, Time Factors, Tomography, X-Ray Computed methods, Treatment Outcome, Aneurysm, False diagnosis, Aneurysm, False surgery, Aorta pathology, Aortic Aneurysm diagnosis, Aortic Aneurysm surgery
- Abstract
Aortic false aneurysm is a rare complication of surgery of the aorta that can occur several months to years after the initial operation. We reviewed our results with false aneurysm repair using deep hypothermia and circulatory arrest. Three patients were reoperated for false aneurysm of the ascending aorta. Femorofemoral cardiopulmonary bypass with a heparinized system was used in all patients. Hypothermic circulatory arrest at an average temperature of 20 degrees C was instituted in all patients for repair. Two patients had a patch repair with pericardium, and the other one had primary repair of the defect. All patients had false aneurysms in the ascending aorta at the site of a previous aortotomy. Two patients had proven infection as the cause. The mean cardiopulmonary bypass time was 183 +/- 20 minutes, and the mean circulatory arrest time was 35 minutes. Operative mortality was not seen. The mean time for extubation in survivors was 10 - 12 hours, and the average time to discharge was 26 days. Aortic false aneurysms can be safely approached using femorofemoral cardiopulmonary bypass, hypothermic circulatory arrest, and patch repair with acceptable operative mortality and long-term survival.
- Published
- 2006
27. Sharp dissection versus electrocautery for radial artery harvesting.
- Author
-
Marzban M, Arya R, Mandegar MH, Karimi AA, Abbasi K, Movahed N, and Abbasi SH
- Subjects
- Female, Humans, Male, Middle Aged, Prospective Studies, Electrocoagulation, Radial Artery surgery, Tissue and Organ Harvesting methods
- Abstract
Radial arteries have been increasingly used during the last decade as conduits for coronary artery revascularization. Although various harvesting techniques have been described, there has been little comparative study of arterial damage and patency. A radial artery graft was used in 44 consecutive patients, who were randomly divided into 2 groups. In the 1st group, the radial artery was harvested by sharp dissection and in the 2nd, by electrocautery. These groups were compared with regard to radial artery free flow, harvest time, number of clips used, complications, and endothelial damage. Radial artery free flow before and after intraluminal administration of papaverine was significantly greater in the electrocautery group (84.3 +/- 50.7 mL/min and 109.7 +/- 68.5 mL/min) than in the sharp-dissection group (52.9 +/- 18.3 mL/min and 69.6 +/- 28.2 mL/ min) (P=0.003). Harvesting time by electrocautery was significantly shorter (25.4 +/- 4.3 min vs 34.4 +/- 5.9 min) (P=0.0001). Electrocautery consumed an average of 9.76 clips, versus 22.45 clips consumed by sharp dissection. The 2 groups were not different regarding postoperative complications, except for 3 cases of temporary paresthesia of the thumb in the electrocautery group; histopathologic examination found no endothelial damage. We conclude that radial artery harvesting by electrocautery is faster and more economical than harvesting by sharp dissection and is associated with better intraoperative flow and good preservation of endothelial integrity.
- Published
- 2006
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.