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Latorre SM, Were VM, Foster AJ, Langner T, Malmgren A, Harant A, Asuke S, Reyes-Avila S, Gupta DR, Jensen C, Ma W, Mahmud NU, Mehebub MS, Mulenga RM, Md Muzahid AN, Paul SK, Fajle Rabby SM, Rahat AAM, Ryder L, Shrestha RK, Sichilima S, Soanes DM, Singh PK, Bentley AR, Saunders DGO, Tosa Y, Croll D, Lamour KH, Islam T, Tembo B, Win J, Talbot NJ, Burbano HA, Kamoun S. Correction: Genomic surveillance uncovers a pandemic clonal lineage of the wheat blast fungus. PLoS Biol 2023; 21:e3002236. [PMID: 39417205 PMCID: PMC11483275 DOI: 10.1371/journal.pbio.3002236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2024] Open
Abstract
[This corrects the article DOI: 10.1371/journal.pbio.3002052.].
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Yan X, Tang B, Ryder LS, MacLean D, Were VM, Eseola AB, Cruz-Mireles N, Ma W, Foster AJ, Osés-Ruiz M, Talbot NJ. The transcriptional landscape of plant infection by the rice blast fungus Magnaporthe oryzae reveals distinct families of temporally co-regulated and structurally conserved effectors. THE PLANT CELL 2023; 35:1360-1385. [PMID: 36808541 PMCID: PMC10118281 DOI: 10.1093/plcell/koad036] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 05/04/2023]
Abstract
The rice blast fungus Magnaporthe oryzae causes a devastating disease that threatens global rice (Oryza sativa) production. Despite intense study, the biology of plant tissue invasion during blast disease remains poorly understood. Here we report a high-resolution transcriptional profiling study of the entire plant-associated development of the blast fungus. Our analysis revealed major temporal changes in fungal gene expression during plant infection. Pathogen gene expression could be classified into 10 modules of temporally co-expressed genes, providing evidence for the induction of pronounced shifts in primary and secondary metabolism, cell signaling, and transcriptional regulation. A set of 863 genes encoding secreted proteins are differentially expressed at specific stages of infection, and 546 genes named MEP (Magnaportheeffector protein) genes were predicted to encode effectors. Computational prediction of structurally related MEPs, including the MAX effector family, revealed their temporal co-regulation in the same co-expression modules. We characterized 32 MEP genes and demonstrate that Mep effectors are predominantly targeted to the cytoplasm of rice cells via the biotrophic interfacial complex and use a common unconventional secretory pathway. Taken together, our study reveals major changes in gene expression associated with blast disease and identifies a diverse repertoire of effectors critical for successful infection.
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Latorre SM, Were VM, Foster AJ, Langner T, Malmgren A, Harant A, Asuke S, Reyes-Avila S, Gupta DR, Jensen C, Ma W, Mahmud NU, Mehebub MS, Mulenga RM, Muzahid ANM, Paul SK, Rabby SMF, Rahat AAM, Ryder L, Shrestha RK, Sichilima S, Soanes DM, Singh PK, Bentley AR, Saunders DGO, Tosa Y, Croll D, Lamour KH, Islam T, Tembo B, Win J, Talbot NJ, Burbano HA, Kamoun S. Genomic surveillance uncovers a pandemic clonal lineage of the wheat blast fungus. PLoS Biol 2023; 21:e3002052. [PMID: 37040332 PMCID: PMC10089362 DOI: 10.1371/journal.pbio.3002052] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/24/2023] [Indexed: 04/12/2023] Open
Abstract
Wheat, one of the most important food crops, is threatened by a blast disease pandemic. Here, we show that a clonal lineage of the wheat blast fungus recently spread to Asia and Africa following two independent introductions from South America. Through a combination of genome analyses and laboratory experiments, we show that the decade-old blast pandemic lineage can be controlled by the Rmg8 disease resistance gene and is sensitive to strobilurin fungicides. However, we also highlight the potential of the pandemic clone to evolve fungicide-insensitive variants and sexually recombine with African lineages. This underscores the urgent need for genomic surveillance to track and mitigate the spread of wheat blast outside of South America and to guide preemptive wheat breeding for blast resistance.
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Latorre SM, Were VM, Foster AJ, Langner T, Malmgren A, Harant A, Asuke S, Reyes-Avila S, Gupta DR, Jensen C, Ma W, Mahmud NU, Mehebub MS, Mulenga RM, Muzahid ANM, Paul SK, Rabby SMF, Rahat AAM, Ryder L, Shrestha RK, Sichilima S, Soanes DM, Singh PK, Bentley AR, Saunders DGO, Tosa Y, Croll D, Lamour KH, Islam T, Tembo B, Win J, Talbot NJ, Burbano HA, Kamoun S. Genomic surveillance uncovers a pandemic clonal lineage of the wheat blast fungus. PLoS Biol 2023; 21:e3002052. [PMID: 37040332 DOI: 10.1101/2022.06.06.494979] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/24/2023] [Indexed: 05/21/2023] Open
Abstract
Wheat, one of the most important food crops, is threatened by a blast disease pandemic. Here, we show that a clonal lineage of the wheat blast fungus recently spread to Asia and Africa following two independent introductions from South America. Through a combination of genome analyses and laboratory experiments, we show that the decade-old blast pandemic lineage can be controlled by the Rmg8 disease resistance gene and is sensitive to strobilurin fungicides. However, we also highlight the potential of the pandemic clone to evolve fungicide-insensitive variants and sexually recombine with African lineages. This underscores the urgent need for genomic surveillance to track and mitigate the spread of wheat blast outside of South America and to guide preemptive wheat breeding for blast resistance.
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Foster AJ, Marrow JP, Allwood MA, Brunt KR, Simpson JA. Applications of a novel radiotelemetry method for the measurement of intrathoracic pressures and physiological rhythms in freely behaving mice. J Appl Physiol (1985) 2020; 129:992-1005. [PMID: 32881619 DOI: 10.1152/japplphysiol.00673.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Techniques to comprehensively evaluate pulmonary function carry a variety of limitations, including the ability to continuously record intrathoracic pressures (ITP), acutely and chronically, in a natural state of freely behaving animals. Measurement of ITP can be used to derive other respiratory parameters, which provide insight to lung health. Our aim was to develop a surgical approach for the placement of a telemetry pressure sensor to measure ITP, providing the ability to chronically measure peak pressure, breath frequency, and timing of the respiratory cycle to facilitate circadian analyses related to breathing patterns. Applications of this technique are shown using a moderate hypoxic challenge. Male C57Bl/6 mice were implanted with radiotelemetry devices to record heart rate, temperature, activity, and ITP during 24-h normoxia, 24-h hypoxia ([Formula: see text] = 0.15), and return to 48-h normoxia. Radiotelemetry of ITP permitted the detection of hypoxia-induced increases in "the ITP equivalent" of ventilation, which were driven by increases in breathing frequency and ITP on a short-term time scale. Respiratory frequency, derived from pressure waveforms, was increased by a decrease in expiratory time without changes in inspiratory time. Chronically, telemetric recording allowed for circadian analyses of respiratory drive, as assessed by inspiratory pressure divided by inspiratory time, which was increased by hypoxia and remained elevated for 48 h of recovery. Furthermore, respiratory frequency demonstrated a circadian rhythm, which was disrupted through the recovery period. In conclusion, radiotelemetry of ITP is a viable, long-term, chronic methodology that extends traditional methods to evaluate respiratory function in mice.NEW & NOTEWORTHY We have demonstrated for the first time in mice that radiotelemetry is an effective tool for the continuous and chronic recording of intrathoracic pressure (ITP) to facilitate circadian rhythm analyses. We show that continuous 24-h hypoxic stress alters the circadian rhythms of heart rate, body temperature, activity, and respiratory parameters, acutely and perpetually, through normoxic recovery. Radiotelemetry of ITP can complement traditional methods for evaluating respiratory function and better our understanding of respiratory pathophysiology.
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Foster AJ, Platt MJ, Huber JS, Eadie AL, Arkell AM, Romanova N, Wright DC, Gillis TE, Murrant CL, Brunt KR, Simpson JA. Central-acting therapeutics alleviate respiratory weakness caused by heart failure-induced ventilatory overdrive. Sci Transl Med 2018; 9:9/390/eaag1303. [PMID: 28515334 DOI: 10.1126/scitranslmed.aag1303] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 03/13/2017] [Indexed: 12/22/2022]
Abstract
Diaphragmatic weakness is a feature of heart failure (HF) associated with dyspnea and exertional fatigue. Most studies have focused on advanced stages of HF, leaving the cause unresolved. The long-standing theory is that pulmonary edema imposes a mechanical stress, resulting in diaphragmatic remodeling, but stable HF patients rarely exhibit pulmonary edema. We investigated how diaphragmatic weakness develops in two mouse models of pressure overload-induced HF. As in HF patients, both models had increased eupneic respiratory pressures and ventilatory drive. Despite the absence of pulmonary edema, diaphragmatic strength progressively declined during pressure overload; this decline correlated with a reduction in diaphragm cross-sectional area and preceded evidence of muscle weakness. We uncovered a functional codependence between angiotensin II and β-adrenergic (β-ADR) signaling, which increased ventilatory drive. Chronic overdrive was associated with increased PERK (double-stranded RNA-activated protein kinase R-like ER kinase) expression and phosphorylation of EIF2α (eukaryotic translation initiation factor 2α), which inhibits protein synthesis. Inhibition of β-ADR signaling after application of pressure overload normalized diaphragm strength, Perk expression, EIF2α phosphorylation, and diaphragmatic cross-sectional area. Only drugs that were able to penetrate the blood-brain barrier were effective in treating ventilatory overdrive and preventing diaphragmatic atrophy. These data provide insight into why similar drugs have different benefits on mortality and symptomatology, despite comparable cardiovascular effects.
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Yemelin A, Brauchler A, Jacob S, Laufer J, Heck L, Foster AJ, Antelo L, Andresen K, Thines E. Identification of factors involved in dimorphism and pathogenicity of Zymoseptoria tritici. PLoS One 2017; 12:e0183065. [PMID: 28829795 PMCID: PMC5568738 DOI: 10.1371/journal.pone.0183065] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 07/28/2017] [Indexed: 01/20/2023] Open
Abstract
A forward genetics approach was applied in order to investigate the molecular basis of morphological transition in the wheat pathogenic fungus Zymoseptoria tritici. Z. tritici is a dimorphic plant pathogen displaying environmentally regulated morphogenetic transition between yeast-like and hyphal growth. Considering the infection mode of Z. tritici, the switching to hyphal growth is essential for pathogenicity allowing the fungus the host invasion through natural openings like stomata. We exploited a previously developed Agrobacterium tumefaciens-mediated transformation (ATMT) to generate a mutant library by insertional mutagenesis including more than 10,000 random mutants. To identify genes involved in dimorphic switch, a plate-based screening system was established. With this approach eleven dimorphic switch deficient random mutants were recovered, ten of which exhibited a yeast-like mode of growth and one mutant predominantly growing filamentously, producing high amount of mycelium under different incubation conditions. Using genome walking approach previously established, the T-DNA integration sites were recovered and the disrupted genomic loci of corresponding mutants were identified and validated within reverse genetics approach. As prove of concept, two of the random mutants obtained were selected for further investigation using targeted gene inactivation. Both genes deduced were found to encode known factors, previously characterized in other fungi: Ssk1p being constituent of HOG pathway and Ade5,7p involved in de novo purine biosynthesis. The targeted mutant strains defective in these genes exhibit a drastically impaired virulence within infection assays on whole wheat plants. Moreover exploiting further physiological assays the predicted function for both gene products could be confirmed in concordance with conserved biological role of homologous proteins previously described in other fungal organisms.
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Jacob S, Grötsch T, Foster AJ, Schüffler A, Rieger PH, Sandjo LP, Liermann JC, Opatz T, Thines E. Unravelling the biosynthesis of pyriculol in the rice blast fungus Magnaporthe oryzae. MICROBIOLOGY-SGM 2017; 163:541-553. [PMID: 27902426 DOI: 10.1099/mic.0.000396] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Pyriculol was isolated from the rice blast fungus Magnaporthe oryzae and found to induce lesion formation on rice leaves. These findings suggest that it could be involved in virulence. The gene MoPKS19 was identified to encode a polyketide synthase essential for the production of the polyketide pyriculol in the rice blast fungus M. oryzae. The transcript abundance of MoPKS19 correlates with the biosynthesis rate of pyriculol in a time-dependent manner. Furthermore, gene inactivation of MoPKS19 resulted in a mutant unable to produce pyriculol, pyriculariol and their dihydro derivatives. Inactivation of a putative oxidase-encoding gene MoC19OXR1, which was found to be located in the genome close to MoPKS19, resulted in a mutant exclusively producing dihydropyriculol and dihydropyriculariol. By contrast, overexpression of MoC19OXR1 resulted in a mutant strain only producing pyriculol. The MoPKS19 cluster, furthermore, comprises two transcription factors MoC19TRF1 and MoC19TRF2, which were both found individually to act as negative regulators repressing gene expression of MoPKS19. Additionally, extracts of ΔMopks19 and ΔMoC19oxr1 made from axenic cultures failed to induce lesions on rice leaves compared to extracts of the wild-type strain. Consequently, pyriculol and its isomer pyriculariol appear to be the only lesion-inducing secondary metabolites produced by M. oryzae wild-type (MoWT) under these culture conditions. Interestingly, the mutants unable to produce pyriculol and pyriculariol were as pathogenic as MoWT, demonstrating that pyriculol is not required for infection.
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Foster AJ, Ryder LS, Kershaw MJ, Talbot NJ. The role of glycerol in the pathogenic lifestyle of the rice blast fungus Magnaporthe oryzae. Environ Microbiol 2017; 19:1008-1016. [PMID: 28165657 DOI: 10.1111/1462-2920.13688] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The rice blast fungus Magnaporthe oryzae elaborates a specialized cell called an appressorium, which is used to breach the tough outer cuticle of a rice leaf, enabling the fungus entry to host plant cells. The appressorium generates enormous turgor by accumulating glycerol to very high concentrations within the cell. Glycerol accumulation and melanization of the appressorium cell wall collectively drive turgor-mediated penetration of the rice leaf. In this review, we discuss the potential metabolic sources of glycerol in the rice blast fungus and how appressorium turgor is focused as physical force at the base of the infection cell, leading to the formation of a rigid penetration peg. We review recent studies of M. oryzae and other relevant appressorium-forming fungi which shed light on how glycerol is synthesized and how appressorium turgor is regulated. Finally, we provide some questions to guide avenues of future research that will be important in fully understanding the role of glycerol in rice blast disease.
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Khandwala AR, Blair J, Harris SB, Foster AJ, Elliot D. Immediate Repair and Early Mobilization of the Extensor Pollicis Longus Tendon in Zones 1 to 4. ACTA ACUST UNITED AC 2017; 29:250-8. [PMID: 15142696 DOI: 10.1016/j.jhsb.2003.12.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2003] [Accepted: 12/18/2003] [Indexed: 11/19/2022]
Abstract
We present the results of repair and early mobilization of 100 extensor pollicis longus (EPL) tendon injuries in zones 1 to 4 in 100 patients using a dynamic outrigger splint which controlled metacarpophalangeal joint movements but allowed free movement of the interphalangeal joint. Eighty-two were complete divisions of the tendon and 18 were 80% to 99% tendon divisions. Analysis of measurements obtained routinely at 8 weeks showed 81% excellent and good results using the TAM system. There were 90% excellent and good results in the 72 patients who were followed-up and received therapy for 12 weeks. Except on the rare occasion when the repair ruptures, loss of thumb extension was not a common functional problem, but scar tethering of the repaired tendon can result in loss of thumb flexion. While loss of metacarpophalangeal joint flexion appeared to have little functional importance, loss of interphalangeal joint flexion and slowing of the movements of this joint can cause functional problems. When interphalangeal joint hyperextension is present before the injury, it is frequently lost but this generally goes unnoticed by the patients. The problems of analysing the EPL injury using the methods of assessment available are discussed.
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Dowd MB, Figus A, Harris SB, Southgate CM, Foster AJ, Elliot D. The Results of Immediate Re-Repair of Zone 1 and 2 Primary Flexor Tendon Repairs which Rupture. ACTA ACUST UNITED AC 2016; 31:507-13. [PMID: 16930791 DOI: 10.1016/j.jhsb.2006.06.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 05/27/2006] [Accepted: 06/12/2006] [Indexed: 11/21/2022]
Abstract
This study reports the outcome of immediate re-repair of primary flexor tendon repairs in zones 1 and 2 of the fingers which had ruptured. Between June 1989 and May 2003, a total of 62 fingers in 61 patients presented with ruptured flexor tendon repairs within 48 hours from rupture. Immediate re-repair and rehabilitation was carried out in 44 fingers (71%) in 43 (70%) patients. Thirty-six patients completed the 8-week therapy programme after re-repair in 37 fingers. Nine (24%) had excellent, 10 (27%) good, 5 (14%) fair and 13 (35%) had poor results when assessed by the original Strickland method. Five fingers in five patients ruptured the re-repair. Poor results and second ruptures were particularly common after re-repair of ruptured tendon repairs in the little finger. In the light of these findings, a policy for dealing with ruptured primary flexor tendon repairs in the fingers is suggested.
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Stoddard DR, Sebesta JA, Welder MD, Foster AJ, Rush RM. What Patients Really Want: Optimizing the Military Preoperative Evaluation Clinic. Mil Med 2016; 181:236-42. [DOI: 10.7205/milmed-d-15-00072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Sherrell DA, Foster AJ, Hudson L, Nutter B, O’Hea J, Nelson S, Paré-Labrosse O, Oghbaey S, Miller RJD, Owen RL. A modular and compact portable mini-endstation for high-precision, high-speed fixed target serial crystallography at FEL and synchrotron sources. JOURNAL OF SYNCHROTRON RADIATION 2015; 22:1372-8. [PMID: 26524301 PMCID: PMC4629865 DOI: 10.1107/s1600577515016938] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 09/10/2015] [Indexed: 05/18/2023]
Abstract
The design and implementation of a compact and portable sample alignment system suitable for use at both synchrotron and free-electron laser (FEL) sources and its performance are described. The system provides the ability to quickly and reliably deliver large numbers of samples using the minimum amount of sample possible, through positioning of fixed target arrays into the X-ray beam. The combination of high-precision stages, high-quality sample viewing, a fast controller and a software layer overcome many of the challenges associated with sample alignment. A straightforward interface that minimizes setup and sample changeover time as well as simplifying communication with the stages during the experiment is also described, together with an intuitive naming convention for defining, tracking and locating sample positions. The setup allows the precise delivery of samples in predefined locations to a specific position in space and time, reliably and simply.
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Allwood MA, Foster AJ, Arkell AM, Beaudoin MS, Snook LA, Romanova N, Murrant CL, Holloway GP, Wright DC, Simpson JA. Respiratory muscle weakness in the Zucker diabetic fatty rat. Am J Physiol Regul Integr Comp Physiol 2015; 309:R780-7. [PMID: 26246509 DOI: 10.1152/ajpregu.00447.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 07/27/2015] [Indexed: 11/22/2022]
Abstract
The obesity epidemic is considered one of the most serious public health problems of the modern world. Physical therapy is the most accessible form of treatment; however, compliance is a major obstacle due to exercise intolerance and dyspnea. Respiratory muscle atrophy is a cause of dyspnea, yet little is known of obesity-induced respiratory muscle dysfunction. Our objective was to investigate whether obesity-induced skeletal muscle wasting occurs in the diaphragm, the main skeletal muscle involved in inspiration, using the Zucker diabetic fatty (ZDF) rat. After 14 wk, ZDF rats developed obesity, hyperglycemia, and insulin resistance, compared with lean controls. Hemodynamic analysis revealed ZDF rats have impaired cardiac relaxation (P = 0.001) with elevated end-diastolic pressure (P = 0.006), indicative of diastolic dysfunction. Assessment of diaphragm function revealed weakness (P = 0.0296) in the absence of intrinsic muscle impairment in ZDF rats. Diaphragm morphology revealed increased fibrosis (P < 0.0001), atrophy (P < 0.0001), and reduced myosin heavy-chain content (P < 0.001), compared with lean controls. These changes are accompanied by activation of the myostatin signaling pathway with increased serum myostatin (P = 0.017), increased gene expression (P = 0.030) in the diaphragm and retroperitoneal adipose (P = 0.033), and increased SMAD2 phosphorylation in the diaphragm (P = 0.048). Here, we have confirmed the presence of respiratory muscle atrophy and weakness in an obese, diabetic model. We have also identified a pathological role for myostatin signaling in obesity, with systemic contributions from the adipose tissue, a nonskeletal muscle source. These findings have significant implications for future treatment strategies of exercise intolerance in an obese, diabetic population.
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Jacob S, Foster AJ, Yemelin A, Thines E. High osmolarity glycerol (HOG) signalling in Magnaporthe oryzae: Identification of MoYPD1 and its role in osmoregulation, fungicide action, and pathogenicity. Fungal Biol 2015; 119:580-94. [DOI: 10.1016/j.funbio.2015.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 02/20/2015] [Accepted: 03/04/2015] [Indexed: 01/22/2023]
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Jacob S, Foster AJ, Yemelin A, Thines E. Histidine kinases mediate differentiation, stress response, and pathogenicity in Magnaporthe oryzae. Microbiologyopen 2014; 3:668-87. [PMID: 25103193 PMCID: PMC4234259 DOI: 10.1002/mbo3.197] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/11/2014] [Accepted: 06/20/2014] [Indexed: 01/11/2023] Open
Abstract
The aim of this study is a functional characterization of 10 putative histidine kinases (HIKs)-encoding genes in the phytopathogenic fungus Magnaporthe oryzae. Two HIKs were found to be required for pathogenicity in the fungus. It was found that the mutant strains ΔMohik5 and ΔMohik8 show abnormal conidial morphology and furthermore ΔMohik5 is unable to form appressoria. Both HIKs MoHik5p and MoHik8p appear to be essential for pathogenicity since the mutants fail to infect rice plants. MoSln1p and MoHik1p were previously reported to be components of the HOG pathway in M. oryzae. The ΔMosln1 mutant is more susceptible to salt stress compared to ΔMohik1, whereas ΔMohik1 appears to be stronger affected by osmotic or sugar stress. In contrast to yeast, the HOG signaling cascade in phytopathogenic fungi apparently comprises more elements. Furthermore, vegetative growth of the mutants ΔMohik5 and ΔMohik9 was found to be sensitive to hypoxia-inducing NaNO2 -treatment. Additionally, it was monitored that NaNO2 -treatment resulted in MoHog1p phosphorylation. As a consequence we assume a first simplified model for hypoxia signaling in M. oryzae including the HOG pathway and the HIKs MoHik5p and MoHik9p.
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Murrant CL, Dodd JD, Foster AJ, Inch KA, Muckle FR, Ruiz DA, Simpson JA, Scholl JHP. Prostaglandins induce vasodilatation of the microvasculature during muscle contraction and induce vasodilatation independent of adenosine. J Physiol 2014; 592:1267-81. [PMID: 24469074 DOI: 10.1113/jphysiol.2013.264259] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Blood flow data from contracting muscle in humans indicates that adenosine (ADO) stimulates the production of nitric oxide (NO) and vasodilating prostaglandins (PG) to produce arteriolar vasodilatation in a redundant fashion such that when one is inhibited the other can compensate. We sought to determine whether these redundant mechanisms are employed at the microvascular level. First, we determined whether PGs were involved in active hyperaemia at the microvascular level. We stimulated four to five skeletal muscle fibres in the anaesthetized hamster cremaster preparation in situ and measured the change in diameter of 2A arterioles (maximum diameter 40 μm, third arteriolar level up from the capillaries) at a site of overlap with the stimulated muscle fibres before and after 2 min of contraction [stimulus frequencies: 4, 20 and 60 Hz at 15 contractions per minute (CPM) or contraction frequencies of 6, 15 or 60 CPM at 20 Hz; 250 ms train duration]. Muscle fibres were stimulated in the absence and presence of the phospholipase A2 inhibitor quinacrine. Further, we applied a range of concentrations of ADO (10(-7)-10(-5) M) extraluminally, (to mimic muscle contraction) in the absence and presence of L-NAME (NO synthase inhibitor), indomethacin (INDO, cyclooxygenase inhibitor) and L-NAME + INDO and observed the response of 2A arterioles. We repeated the latter experiment on a different level of the cremaster microvasculature (1A arterioles) and on the microvasculature of a different skeletal muscle (gluteus maximus, 2A arterioles). We observed that quinacrine inhibited vasodilatation during muscle contraction at intermediate and high contraction frequencies (15 and 60 CPM). L-NAME, INDO and L-NAME + INDO were not effective at inhibiting vasodilatation induced by any concentration of ADO tested in 2A and 1A arterioles in the cremaster muscle or 2A arterioles in the gluteus maximus muscle. Our data show that PGs are involved in the vasodilatation of the microvasculature in response to muscle contraction but did not obtain evidence that extraluminal ADO causes vasodilatation through NO or PG or both. Thus, we propose that PG-induced microvascular vasodilation during exercise is independent of ADO.
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Jae J, Tompsett GA, Foster AJ, Hammond KD, Auerbach SM, Lobo RF, Huber GW. Investigation into the shape selectivity of zeolite catalysts for biomass conversion. J Catal 2011. [DOI: 10.1016/j.jcat.2011.01.019] [Citation(s) in RCA: 699] [Impact Index Per Article: 49.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Foster AJ, Lobo RF. Identifying reaction intermediates and catalytic active sites through in situ characterization techniques. Chem Soc Rev 2010; 39:4783-93. [PMID: 21038051 DOI: 10.1039/c0cs00016g] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This tutorial review centers on recent advances and applications of experimental techniques that help characterize surface species and catalyst structures under in situ conditions. We start by reviewing recent applications of IR spectroscopy of working catalysis, emphasizing newer approaches such as Sum Frequency Generation and Polarization Modulation-infrared reflection absorption spectroscopy. This is followed by a section on solid-state NMR spectroscopy for the detection of surface species and reaction intermediates. These two techniques provide information mainly about the concentration and identity of the prevalent surface species. The following sections center on methods that provide structural and chemical information about the catalyst surface. The increasingly important role of high-pressure X-ray photoelectron spectroscopy in catalyst characterization is evident from the new and interesting information obtained on supported catalysts as presented in recent reports. X-Ray absorption spectroscopy (XANES and EXAFS) is used increasingly under reaction conditions to great advantage, although is inherently limited to systems where the bulk of the species in the sample are surface species. However, the ability of X-rays to penetrate the sample has been used cleverly by a number of groups to understand how changing reaction conditions change the structure and composition of surface atoms on supported catalyst.
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Kramer B, Thines E, Foster AJ. MAP kinase signalling pathway components and targets conserved between the distantly related plant pathogenic fungi Mycosphaerella graminicola and Magnaporthe grisea. Fungal Genet Biol 2009; 46:667-81. [PMID: 19520179 DOI: 10.1016/j.fgb.2009.06.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 05/23/2009] [Accepted: 06/03/2009] [Indexed: 02/04/2023]
Abstract
Mycosphaerella graminicola is a dimorphic fungus which causes Septoria tritici leaf blotch. This report describes the examination of the role of several components of the Pmk1p/Fus3p mitogen-activated protein kinase (MAPK) signalling pathway in the development of this species. The genes encoding the MAPK kinase kinase MgSte11p and the MAPK kinase MgSte7p were found to be indispensible for pathogenicity while the deletion of the gene encoding the proposed scaffold protein MgSte50p led to a reduction in virulence. These phenotypes were attributed to a reduced ability to form filaments on the plant surface which prevented penetration. A delayed disease progression was observed on deletion of the gene MGSTE12. The MGSTE7, MGSTE50 and MGSTE12 genes were able to complement mutants of Magnaporthe grisea lacking the orthologous genes. Interactions between the My. graminicola signalling components were also investigated. Furthermore genes whose MgSte12p/Mst12p dependence is conserved between My. graminicola and Ma. grisea were identified.
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Odenbach D, Thines E, Anke H, Foster AJ. The Magnaporthe grisea class VII chitin synthase is required for normal appressorial development and function. MOLECULAR PLANT PATHOLOGY 2009; 10:81-94. [PMID: 19161355 PMCID: PMC6640330 DOI: 10.1111/j.1364-3703.2008.00515.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The plant pathogenic fungus Magnaporthe grisea is able to enter its host via appressorium-mediated penetration. Earlier investigations have shown that these infection structures are rich in the cell wall polysaccharide chitin. Previously, we have described how the transcription of a class VII chitin synthase-encoding gene CHS7 is completely dependent on the putative transcription factor Con7p during the germination of conidia, and how con7(-) mutants are unable to form appressoria under any conditions tested. Because of the pleiotropic effects of the con7(-) mutation, we examined the consequences of the targeted deletion of CHS7. The chs7(-) mutants generated were unable to form appressoria on artificial surfaces, except following the application of the exogenous inducers 1,16-hexadecanediol and cyclic adenosine monophosphate. The appressoria formed had a reduced chitin content and were often found to be smaller and misshapen compared with the wild-type. chs7(-) mutants were significantly reduced in their ability to enter rice plants, but growth in planta was not affected. Reverse transcriptase-polymerase chain reaction analysis demonstrated that CHS7 transcription was strongly induced on germination of spores, and a green fluorescent protein-tagged Chs7p protein was found to be produced abundantly during infection-related morphogenesis. Together, these data suggest that the class VII chitin synthase Chs7p of M. grisea is required for normal appressorium formation and function.
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Foster AJ, Bird RA, Smith SN. Biotinylation and characterization of Cryptococcus neoformans cell surface proteins. J Appl Microbiol 2008; 103:390-9. [PMID: 17650199 DOI: 10.1111/j.1365-2672.2006.03259.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIMS To develop a novel procedure for isolating and characterizing cryptococcal cell-surface proteins using biotinylation, fluorescein isothiocyanate (FITC)-streptavidin, flow cytometry and associated ligand-receptor analysis, confocal microscopy and electrophoretic separation. METHODS AND RESULTS Cell proteins of both acapsulate and encapsulated Cryptococcus neoformans cells were labelled using sulfo-NHS-biotin which, in turn, was complexed with FITC-streptavidin. Resulting cell population fluorescence supported visualization of cell-surface protein distribution by confocal microscopy, as well as evaluation of protein exposure by flow cytometry and the calculation of the ligand-binding determinants EC(50), F(max) and H(n). Biotinylation of cell-surface proteins also supported their isolation by affinity chromatography and characterization by SDS/PAGE. Ligand-binding determinants, such as EC(50) values, indicated that acapsulate and stationary phase cells have greatest affinity for biotin. F(max) values demonstrated greatest protein exposure among stationary phase cells; in turn, encapsulated cells expose more protein than acapsulate counterparts. H(n) values of below unity potentially confirm the complex multi-receptor nature of biotin binding to cryptococcal cell surfaces under investigation. Fluorescence visualization showed marked but localized fluorescence indicative of protein exposure around sites of cell division. In turn, biotinylation of cell-surface proteins and their release under reducing conditions demonstrated at least two noncovalently linked proteinaceous entities, of 43 and 57 kDa, exposed on acapsulate cryptococcal cell walls. CONCLUSIONS A novel method for identifying, in situ, cell-surface proteins exposed by C. neoformans was established. This novel technique was successfully implemented using both acapsulate and encapsulated C. neoformans cells, both were found to have dynamic and markedly localized protein distribution around sites of cell division and associated cell wall trauma. SIGNIFICANCE AND IMPACT OF THE STUDY A novel procedure, employing a versatile combination of flow cytometry, ligand-receptor analysis, confocal microscopy and biotinylation, supported the characterization and isolation of cryptococcal cell-surface proteins.
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Odenbach D, Breth B, Thines E, Weber RWS, Anke H, Foster AJ. The transcription factor Con7p is a central regulator of infection-related morphogenesis in the rice blast fungus Magnaporthe grisea. Mol Microbiol 2007; 64:293-307. [PMID: 17378924 DOI: 10.1111/j.1365-2958.2007.05643.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A strain harbouring an insertion within the promoter of the CON7 gene of Magnaporthe grisea was isolated. This gene was previously shown to be essential for appressorium formation and growth in planta and is predicted to encode a transcription factor. Microarray-based gene expression analysis was used to identify several genes whose transcription during germination depends on Con7p. These include the pathogenicity factor-encoding gene PTH11 and several other genes which like PTH11 are predicted to encode G protein-coupled receptors. Microarray analysis also revealed several Con7p-dependent genes which may encode factors determining cell wall structure or function, either through the synthesis/degradation of cell wall components or by association with the cell exterior. One Con7p-dependent gene predicted to encode a class VII chitin synthase was deleted, leading to dramatic consequences on the pathogenic development of the resultant strain. Within the con7(-) mutant, a 29% reduction in chitin content of germinated spores was found and the mutant was hypersensitive to the chitin synthase inhibitor nikkomycin Z. A green fluorescent protein-tagged Con7p was found to have nuclear localization within spores. Taken together, these observations suggest that Con7p encodes a transcription factor required for the transcription of several genes which participate in disease-related morphogenesis in M. grisea.
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Hof C, Eisfeld K, Welzel K, Antelo L, Foster AJ, Anke H. Ferricrocin synthesis in Magnaporthe grisea and its role in pathogenicity in rice. MOLECULAR PLANT PATHOLOGY 2007; 8:163-172. [PMID: 20507488 DOI: 10.1111/j.1364-3703.2007.00380.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
SUMMARY Iron is an essential element for the growth of nearly all organisms. In order to overcome the problem of its low bioavailability, microorganisms (including fungi) secrete siderophores, high-affinity iron chelators. As the acquisition of iron is also a key step in infection processes, siderophores have been considered as potential virulence factors in several host-pathogen interactions. Most fungi produce siderophores of the hydroxamate-type, which are synthesized by non-ribosomal peptide synthetases (NRPSs). Magnaporthe grisea, the causal agent of rice blast disease, produces ferricrocin as intracellular storage siderophore and excretes coprogens. In the M. grisea genome we identified SSM1, an NRPS gene, and a gene encoding an l-ornithine N5-monooxygenase (OMO1) that is clustered with SSM1 and responsible for catalysing the first step in siderophore biosynthesis, the N(5) hydroxylation of ornithine. Disruption of SSM1 confirmed that the gene encodes ferricrocin synthetase. Pathogenicity of these mutants towards rice was reduced, suggesting a role of this siderophore in pathogenicity of M. grisea.
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