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Powell AJ, Kim SH, Cordero J, Vujanovic V. Protocooperative Effect of Sphaerodes mycoparasitica Biocontrol and Crop Genotypes on FHB Mycotoxin Reduction in Bread and Durum Wheat Grains Intended for Human and Animal Consumption. Microorganisms 2023; 11:microorganisms11010159. [PMID: 36677451 PMCID: PMC9861577 DOI: 10.3390/microorganisms11010159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/29/2022] [Accepted: 12/31/2022] [Indexed: 01/11/2023] Open
Abstract
The occurrence of Fusarium Head Blight (FHB) mycotoxins in wheat grains is a major threat to global food safety and security. Humans and animals are continuously being exposed to Fusarium mycotoxins such as deoxynivalenol (DON) and its acetylated derivatives 3ADON and 15ADON through the ingestion of contaminated food or grain-based diet. In this study, a host-specific mycoparasite biocontrol agent (BCA), Sphaerodes mycoparasitica, significantly reduced FHB mycotoxin occurrence in harvested wheat grains from Fusarium graminearum 3ADON chemotype infected plants in greenhouse. Four genotypes of wheat, two common wheat and two durum wheat cultivars with varying FHB resistance levels were used in this study. Principal Coordinate Analysis (PCoA) using Illumina ITS sequences depicted beta diversity changes in Fusarium species indicating that both plant cultivar and BCA treatments influenced the Fusarium species structure and mycotoxin occurrence in grains. Fusarium graminearum complex (cluster A), F. avenaceum and F. acuminatum (cluster B), and F. proliferatum (cluster C) variants were associated with different FHB mycotoxins based on LC-MS/MS analyses. The predominant FHB mycotoxins measured were DON and its acetylated derivatives 3ADON and 15ADON. The BCA reduced the occurrence of DON in grains of all four cultivars (common wheat: 1000-30,000 µg·kg-1.; durum wheat: 600-1000 µg·kg-1) to levels below the Limit of Quantification (LOQ) of 16 µg·kg-1. A relatively higher concentration of DON was detected in the two common wheat genotypes when compared to the durum wheat genotype; however, the percentage reduction in the wheat genotypes was greater, reaching up to 99% with some S. mycoparasitica treatments. Similarly, a higher reduction in DON was measured in susceptible genotypes than in resistant genotypes. This study's findings underscore the potential of a Fusarium-specific S. mycoparasitica BCA as a safe and promising alternative that can be used in conjunction with other management practices to minimize FHB mycotoxins in cereal grain, food and feed intended for human and animal consumption.
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Perez MT, Bucholz E, Asimacopoulos E, Ferraro AM, Salem SM, Schauer J, Holleman C, Sekhavat S, Tworetzky W, Powell AJ, Sleeper LA, Beroukhim RS. Impact of maternal social vulnerability and timing of prenatal care on outcome of prenatally detected congenital heart disease. Ultrasound Obstet Gynecol 2022; 60:346-358. [PMID: 35061294 DOI: 10.1002/uog.24863] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/30/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
OBJECTIVES Early prenatal detection of congenital heart disease (CHD) allows mothers to plan for their pregnancy and delivery; however, the effect of certain sociodemographic and fetal factors on prenatal care has not been investigated thoroughly. This study evaluated the impact of maternal and fetal characteristics on the timing of prenatal diagnosis of CHD and fetal and postnatal outcomes. METHODS This retrospective multicenter cohort study included women with a fetal echocardiographic diagnosis of CHD between 2010 and 2019. Women were grouped into quartiles of social vulnerability (quartiles 1-4; low-high) using the 2014 social vulnerability index (SVI) provided by the Centers for Disease Control and Prevention. A fetal disease severity score (range, 1-7) was calculated based on a combination of CHD severity (mild = 1; moderate = 2; severe, two ventricles = 3; severe, single ventricle = 4 points) and prenatally diagnosed genetic abnormality, non-cardiac abnormality and fetal hydrops (1 point each). Late diagnosis was defined as a fetal echocardiographic diagnosis of CHD after 24 weeks' gestation. Univariate and multivariable regression analyses were used to identify factors associated with late diagnosis, termination of pregnancy (TOP), postnatal death, prenatal-postnatal discordance in CHD diagnosis and severity and, for liveborn infants, to identify which prenatal variables were associated with postnatal death or heart transplant. RESULTS Among 441 pregnancies included, 94 (21%) had a late diagnosis of CHD. Late diagnosis was more common in the most socially vulnerable quartile, 38% of women in this group having diagnosis > 24 weeks, compared with 14-18% in the other three quartile groups. Late diagnosis was also associated with Catholic or other Christian religion vs non-denominational or other religion and with a lower fetal disease severity score. There were 93 (21%) TOP and 26 (6%) in-utero fetal demises. Factors associated with TOP included early diagnosis and greater fetal disease severity. Compared with the other quartiles, the most socially vulnerable quartile had a higher incidence of in-utero fetal demise and a lower incidence of TOP. Among the 322 liveborn infants, 49 (15%) died or underwent heart transplant during the follow-up period (range, 0-16 months). Factors associated with postnatal death or heart transplant included longer delay between obstetric ultrasound examination at which CHD was first suspected and fetal echocardiogram at which CHD was confirmed and greater fetal disease severity. CONCLUSIONS High social vulnerability, Catholic or other Christian religion and low fetal disease severity are associated with late prenatal CHD diagnosis. Delays in CHD diagnosis are associated with fewer TOPs and worse postnatal outcome. Therefore, efforts to expedite fetal echocardiography following abnormal obstetric screening, particularly for at-risk women (e.g. those with high SVI), have the potential to impact pregnancy and postnatal outcome among the prenatally diagnosed CHD population. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.
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Affiliation(s)
- M T Perez
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Department of Pediatrics, Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - E Bucholz
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - E Asimacopoulos
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
| | - A M Ferraro
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Department of General Surgery and Surgical Specialties 'Paride Stefanini', Sapienza University of Rome, Rome, Italy
| | - S M Salem
- Department of Anesthesiology, Critical Care and Pain Medicine, Boston Children's Hospital, Boston, MA, USA
| | - J Schauer
- Department of Pediatrics, Seattle Children's Hospital, Seattle, WA, USA
| | | | - S Sekhavat
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Department of Pediatrics, Boston Medical Center, Boston, MA, USA
| | - W Tworetzky
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - A J Powell
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - L A Sleeper
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - R S Beroukhim
- Department of Cardiology, Boston Children's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
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Powell AJ, Crua E, Chong BC, Gordon R, McAuslan A, Pitto RP, Clatworthy MG. A randomized prospective study comparing mobile-bearing against fixed-bearing PFC Sigma cruciate-retaining total knee arthroplasties with ten-year minimum follow-up. Bone Joint J 2018; 100-B:1336-1344. [PMID: 30295539 DOI: 10.1302/0301-620x.100b10.bjj-2017-1450.r1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
AIMS This study compares the PFC total knee arthroplasty (TKA) system in a prospective randomized control trial (RCT) of the mobile-bearing rotating-platform (RP) TKA against the fixed-bearing (FB) TKA. This is the largest RCT with the longest follow-up where cruciate-retaining PFC total knee arthroplasties are compared in a non-bilateral TKA study. PATIENTS AND METHODS A total of 167 patients (190 knees with 23 bilateral cases), were recruited prospectively and randomly assigned, with 91 knees receiving the RP and 99 knees receiving FB. The mean age was 65.5 years (48 to 82), the mean body mass index (BMI) was 29.7 kg/m2 (20 to 52) and 73 patients were female. The Knee Society Score (KSS), Knee Society Functional Score (KSFS), Oxford Knee Score (OKS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and 12-Item Short-Form Health Survey Physical and Mental Component Scores (SF-12 PCS, SF-12 MCS) were gathered and recorded preoperatively, at five-years' follow-up, and at ten years' follow-up. Additionally, Knee Injury and Osteoarthritis Outcome Scores (KOOS) were collected at five- and ten-year follow-ups. The prevalence of radiolucent lines (RL) on radiographs and implant survival were recorded at five- and ten-year follow-ups. RESULTS At the ten-year follow-up, the RP group (n = 39) had a statistically significant superior score in the OKS (p = 0.001), WOMAC (p = 0.023), SF-12 PCS (p = 0.019), KOOS Activities of Daily Living (ADL) (p = 0.010), and KOOS Sport and Recreation (Sport/Rec) (p = 0.006) compared with the FB group (n = 46). The OKS, SF-12 PCS, and KOOS Sport/Rec at ten years had mean scores above the minimal clinically important difference (MCID) threshold. There was no significant difference in prevalence of radiolucency between groups at five-years' follow-up (p = 0.449), nor at ten-years' follow-up (p = 0.08). Implant survival rate at 14 years postoperative was 95.2 (95% CI 90.7 to 99.8) and 94.7 (95% CI 86.8 to 100.0) for the RP and FB TKAs, respectively. CONCLUSION At ten-year follow-up, the mobile-bearing knee joint arthroplasty had statistically and clinically relevant superior OKS, SF-12 PCS, and KOOS (Sport/Rec) than the fixed-bearing platform. No difference was seen in prevalence of radiolucent lines. There was a greater than 94% implant survival rate for both cohorts at 14 years. Cite this article: Bone Joint J 2018;100-B:1336-44.
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Affiliation(s)
- A J Powell
- Department of Trauma and Orthopaedic Surgery, Middlemore and Ascot Hospitals, Auckland, New Zealand
| | - E Crua
- Department of Trauma and Orthopaedic Surgery, Ascot Hospital, Auckland, New Zealand
| | - B C Chong
- University of Auckland, School of Medicine, Auckland, New Zealand
| | - R Gordon
- Department of Trauma and Orthopaedic Surgery, Middlemore and Ascot Hospitals, Auckland, New Zealand
| | - A McAuslan
- Department of Trauma and Orthopaedic Surgery, Middlemore and Ascot Hospitals, Auckland, New Zealand
| | - R P Pitto
- Department of Trauma and Orthopaedic Surgery, Middlemore and Ascot Hospitals, Auckland, New Zealand
| | - M G Clatworthy
- Department of Trauma and Orthopaedic Surgery, Middlemore and Ascot Hospitals, Auckland, New Zealand
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Abstract
Olecranon fractures are common. They are usually managed surgically with open reduction and either tension band wiring or plate fixation. Currently, there are few studies comparing fracture treatments. We aim to review the available literature to guide the orthopaedic surgeon on the management of these fractures. A literature review of peer-reviewed publications in international orthopaedic journals detailing olecranon fracture treatment was conducted. An additional focus was placed on the evidence base for and surgical outcomes of tension band wiring for common two-part fractures. Our novel illustrations aim to educate the reader, and our treatment algorithm provides guidance for management. 10% of all upper limb fractures involve the olecranon, and most are simple two-part injuries. These should be managed with tension band wire constructs. Non-displaced fractures can be treated conservatively. Displaced complex injuries necessitate locking plate fixation. Currently, there exits a lack of studies comparing these treatments. There may be an emerging role for intramedullary nail fixation. Non-operative management in the elderly comorbid patient remains controversial. Prospective, randomised controlled trials of matched patients and fracture patterns comparing operative techniques are needed as there is a lack of level I/II evidence to support the use of one implant over another.
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Affiliation(s)
- A J Powell
- Department of Trauma and Orthopaedic Surgery, Royal Alexandra Hospital, Corsebar Rd, Paisley, PA2 9PN, UK.
| | - O M Farhan-Alanie
- Department of Trauma and Orthopaedic Surgery, Glasgow Royal Infirmary, Glasgow, UK
| | - J K Bryceland
- Department of Trauma and Orthopaedic Surgery, Glasgow Royal Infirmary, Glasgow, UK
| | - T Nunn
- Department of Trauma and Orthopaedic Surgery, Royal Alexandra Hospital, Corsebar Rd, Paisley, PA2 9PN, UK
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Ballini E, Virginio C, Medhurst SJ, Summerfield SG, Aldegheri L, Buson A, Carignani C, Chen YH, Giacometti A, Lago I, Powell AJ, Jarolimek W. Characterization of three diaminopyrimidines as potent and selective antagonists of P2X3 and P2X2/3 receptors with in vivo efficacy in a pain model. Br J Pharmacol 2011; 163:1315-25. [PMID: 21410458 DOI: 10.1111/j.1476-5381.2011.01322.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE P2X3 and P2X2/3 receptors are highly localized on the peripheral and central pathways of nociceptive signal transmission. The discovery of A-317491 allowed their validation as chronic inflammatory and neuropathic pain targets, but this molecule has a very limited oral bioavailability and CNS penetration. Recently, potent P2X3 and P2X2/3 blockers with a diaminopyrimidine core group and better bioavailability were synthesized and represent a new opportunity for the validation of P2X3-containing receptors as targets for pain. Here we present a characterization of three representative diaminopyrimidines. EXPERIMENTAL APPROACH The activity of compounds was evaluated in intracellular calcium flux and electrophysiological recordings from P2X receptors expressed in mammalian cells and in a in vivo model of inflammatory pain (complete Freund's adjuvant (CFA) in rat paws). KEY RESULTS Compound A potently blocked P2X3 (pIC(50)= 7.39) and P2X2/3 (pIC(50)=6.68) and showed no detectable activity at P2X1, P2X2, P2X4 and P2X7 receptors (pIC(50)< 4.7). Whole-cell voltage clamp electrophysiology confirmed these results. Compounds showed good selectivities when tested against a panel of different classes of target. In the CFA model, compound B showed significant anti-nociceptive effects (57% reversal at 3mg·kg(-1) ). CONCLUSIONS AND IMPLICATIONS The diaminopyrimidines were potent and selective P2X3 and P2X2/3 receptor antagonists, showing efficacy in vivo and represent useful tools to validate these receptors as targets for inflammatory and neuropathic pain and provide promising progress in the identification of therapeutic tools for the treatment of pain-related disorders.
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Affiliation(s)
- E Ballini
- GlaxoSmithKline, Molecular Discovery Research, Verona, Italy.
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Rhodes J, Margossian R, Darras BT, Colan SD, Jenkins KJ, Geva T, Powell AJ. Safety and efficacy of carvedilol therapy for patients with dilated cardiomyopathy secondary to muscular dystrophy. Pediatr Cardiol 2008; 29:343-51. [PMID: 17885779 DOI: 10.1007/s00246-007-9113-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 07/03/2007] [Accepted: 07/10/2007] [Indexed: 01/16/2023]
Abstract
BACKGROUND By the age of 20 years, almost all patients with Duchenne's or Becker's muscular dystrophy have experienced dilated cardiomyopathy (DCM), a condition that contributes significantly to their morbidity and mortality. Although studies have shown carvedilol to be an effective therapy for patients with other forms of DCM, few data exist concerning its safety and efficacy for patients with muscular dystrophy. This study aimed to evaluate the safety and efficacy of carvedilol for patients with DCM. METHODS A clinical trial at an outpatient clinic investigated 22 muscular dystrophy patients, ages 14 to 46 years, with DCM and left ventricular ejection fraction (LVEF) less than 50%. Carvedilol up-titrated over 8 weeks then was administered at the maximum or highest tolerated dose for 6 months. Baseline and posttreatment cardiac magnetic resonance imaging (CMR), echocardiography, and Holter monitoring were recorded. RESULTS Carvedilol therapy was associated with a modest but statistically significant improvement in CMR-derived ejection fraction (41% +/- 8.3% to 43% +/- 8%; p < 0.02). Carvedilol also was associated with significant improvements in both the mean rate of pressure rise (dP/dt) during isovolumetric contraction (804 +/- 216 to 951 +/- 282 mmHg/s; p < 0.05) and the myocardial performance index (0.55 +/- 0.18 to 0.42 +/- 0.15; p < 0.01). A trend toward improved shortening fraction, E/E' ratio, and isovolumetric relaxation time also was observed. Two patients had runs of nonsustained ventricular tachycardia exceeding 140 beats per minute (bpm) before carvedilol administration. Ventricular tachycardia exceeding 140 bpm was not observed after carvedilol therapy. Carvedilol was well tolerated, and no serious adverse events were identified. CONCLUSIONS Carvedilol therapy appears to be safe for patients with DCM secondary to muscular dystrophy and produces a modest improvement in systolic and diastolic function.
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Affiliation(s)
- J Rhodes
- Department of Cardiology, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA 02115, USA.
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Knauth AL, Gauvreau K, Powell AJ, Landzberg MJ, Walsh EP, Lock JE, del Nido PJ, Geva T. Ventricular size and function assessed by cardiac MRI predict major adverse clinical outcomes late after tetralogy of Fallot repair. Heart 2006; 94:211-6. [PMID: 17135219 DOI: 10.1136/hrt.2006.104745] [Citation(s) in RCA: 347] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Factors associated with impaired clinical status in a cross-sectional study of patients with repaired tetralogy of Fallot (TOF) have been reported previously. OBJECTIVES To determine independent predictors of major adverse clinical outcomes late after TOF repair in the same cohort during follow-up evaluated by cardiac magnetic resonance (CMR). METHODS Clinical status at latest follow-up was ascertained in 88 patients (median time from TOF repair to baseline evaluation 20.7 years; median follow-up from baseline evaluation to most recent follow-up 4.2 years). Major adverse outcomes included (a) death; (b) sustained ventricular tachycardia; and (c) increase in NYHA class to grade III or IV. RESULTS 22 major adverse outcomes occurred in 18 patients (20.5%): death in 4, sustained ventricular tachycardia in 8, and increase in NYHA class in 10. Multivariate analysis identified right ventricular (RV) end-diastolic volume Z >or=7 (odds ratio (OR) = 4.55, 95% confidence interval (CI) 1.10 to 18.8, p = 0.037) and left ventricular (LV) ejection fraction <55% (OR = 8.05, 95% CI 2.14 to 30.2, p = 0.002) as independent predictors of outcome with an area under the receiver operator characteristic curve of 0.850. LV ejection fraction could be replaced by RV ejection fraction <45% in the multivariate model. QRS duration >or=180 ms also predicted major adverse events but correlated with RV size. CONCLUSIONS In this cohort, severe RV dilatation and either LV or RV dysfunction assessed by CMR predicted major adverse clinical events. This information may guide risk stratification and therapeutic interventions.
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Affiliation(s)
- A L Knauth
- Department of Cardiology, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA 02115, USA
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Meadows LS, Chen YH, Powell AJ, Clare JJ, Ragsdale DS. Functional modulation of human brain Nav1.3 sodium channels, expressed in mammalian cells, by auxiliary beta 1, beta 2 and beta 3 subunits. Neuroscience 2002; 114:745-53. [PMID: 12220575 DOI: 10.1016/s0306-4522(02)00242-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Voltage-gated sodium channels consist of a pore-forming alpha subunit and two auxiliary beta subunits. Excitable cells express multiple alpha subtypes, designated Na(v)1.1-Na(v)1.9, and three beta subunits, designated beta1, beta2 and beta3. Understanding how the different alpha subtypes, in combination with the various beta subunits, determine sodium channel behavior is important for elucidating the molecular basis of sodium channel functional diversity. In this study, we used whole-cell electrophysiological recording to examine the properties of the human Na(v)1.3 alpha subtype, stably expressed in Chinese hamster ovary cells, and to investigate modulation of Na(v)1.3 function by beta1, beta2 and beta3 subunits. In the absence of beta subunits, human Na(v)1.3 formed channels that inactivated rapidly (tau(inactivation) approximately equals 0.5 ms at 0 mV) and almost completely by the end of 190-ms-long depolarizations. Using an intracellular solution with aspartate as the main anion, the midpoint for channel activation was approximately -12 mV. The midpoint for inactivation, determined using 100-ms conditioning pulses, was approximately -47 mV. The time constant for repriming of inactivated channels at -80 mV was approximately 6 ms. Coexpression of beta1 or beta3 did not affect inactivation time course or the voltage dependence of activation, but shifted the inactivation curve approximately 10 mV negative, and slowed the repriming rate ca. three-fold. beta2 did not affect channel properties, either by itself or in combination with beta1 or beta3. Na(v)1.3 expression is increased in damaged nociceptive peripheral afferents. This change in channel expression levels is correlated with the emergence of a rapidly inactivating and rapidly repriming sodium current, which has been proposed to contribute to the pathophysiology of neuropathic pain. The results of this study support the hypothesis that Na(v)1.3 may mediate this fast sodium current.
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Affiliation(s)
- L S Meadows
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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Affiliation(s)
- A J Powell
- Department of Cardiology, Children's Hospital, Boston, Masschusetts 02115, USA.
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Powell AJ, Jacobson DJ, Natvig DO. Allelic diversity at the het-c locus in Neurospora tetrasperma confirms outcrossing in nature and reveals an evolutionary dilemma for pseudohomothallic ascomycetes. J Mol Evol 2001; 52:94-102. [PMID: 11139299 DOI: 10.1007/s002390010138] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vegetative cells of the filamentous ascomycete Neurospora tetrasperma are typically heterokaryotic, possessing haploid nuclei of both A and a mating types. As a consequence, N. tetrasperma is self-fertile. This life cycle, referred to as pseudohomothallism, clearly derives from true heterothallism of the type exhibited by related species such as N. crassa. Occasional homokaryotic, single-mating-type (heterothallic) isolates occur; in the laboratory, such strains can be outcrossed. The potential for outcrossing in N. tetrasperma raises the question of how this organism avoids heterokaryon incompatibility. Heterokaryon incompatability in vegetatively growing fungi is controlled by multiple loci. Two strains must be identical at each het locus (11 in N. crassa) to form a stable heterokaryon. Prior to the present survey, it seemed plausible that N. tetrasperma avoids heterokaryon incompatibility by maintaining compatible allele combinations through continual selfing. A survey of het-c variation among wild-type isolates in this study demonstrated that N. tetrasperma outcrosses in nature and that such matings can result in incompatible combinations of het-c alleles. Whereas individual wild-type isolates are invariably homoallelic for het-c, closely related strains may possess functionally different het-c alleles, which predate the origin of N. tetrasperma. Therefore, pseudohomothallic ascomycetes such as N. tetrasperma face an apparent evolutionary dilemma: the benefits of outcrossing must be balanced against the fact that matings can produce unstable heterokaryons and disrupt the pseudohomothallic life cycle.
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Affiliation(s)
- A J Powell
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
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Abstract
Management of all patients with pulmonary atresia, intact ventricular septum, and right ventricle-dependent coronary circulation (n = 12) with staged surgery directed toward a Fontan palliation resulted in an 83% 5-year actuarial survival. Both deaths in the study were presumably related to coronary ischemia and occurred in the first 4 months of life.
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Affiliation(s)
- A J Powell
- Department of Cardiology, Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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Powell AJ, Read JA, Banfield MJ, Gunn-Moore F, Yan SD, Lustbader J, Stern AR, Stern DM, Brady RL. Recognition of structurally diverse substrates by type II 3-hydroxyacyl-CoA dehydrogenase (HADH II)/amyloid-beta binding alcohol dehydrogenase (ABAD). J Mol Biol 2000; 303:311-27. [PMID: 11023795 DOI: 10.1006/jmbi.2000.4139] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human type II hydroxyacyl-CoA dehydrogenase/amyloid-beta binding alcohol dehydrogenase (HADH II/ABAD) is an oxidoreductase whose salient features include broad substrate specificity, encompassing 3-hydroxyacyl-CoA derivatives, hydroxysteroids, alcohols and beta-hydroxybutyrate, and the capacity to bind amyloid-beta peptide, leading to propagation of amyloid-induced cell stress. In this study, we examine the structure and enzymatic activity of the homologous rat HADH II/ABAD enzyme. We report the crystal structure of rat HADH II/ABAD as a binary complex with its NADH cofactor to 2.0 A resolution, as a ternary complex with NAD(+) and 3-ketobutyrate (acetoacetate) to 1.4 A resolution, and as a ternary complex with NADH and 17 beta-estradiol to 1.7 A resolution. This first crystal structure of an HADH II confirms these enzymes are closely related to the short-chain hydroxysteroid dehydrogenases and differ substantially from the classic, type I 3-hydroxyacyl-CoA dehydrogenases. Binding of the ketobutyrate substrate is accompanied by closure of the active site specificity loop, whereas the steroid substrate does not appear to require closure for binding. Despite the different chemical nature of the two bound substrates, the presentation of chemical groups within the active site of each complex is remarkably similar, allowing a general mechanism for catalytic activity to be proposed. There is a characteristic extension to the active site that is likely to accommodate the CoA moiety of 3-hydroxyacyl-CoA substrates. Rat HADH II/ABAD also binds amyloid-beta (1-40) peptide with a K(D) of 21 nM, which is similar to the interaction exhibited between this peptide and human HADH II/ABAD. These studies provide the first structural insights into HADH II/ABAD interaction with its substrates, and indicate the relevance of the rodent enzyme and associated rodent models for analysis of HADH II/ABAD's physiologic and pathophysiologic properties.
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Affiliation(s)
- A J Powell
- Department of Biochemistry, University of Bristol, Bristol, UK
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Need LR, Powell AJ, del Nido P, Geva T. Coronary echocardiography in tetralogy of fallot: diagnostic accuracy, resource utilization and surgical implications over 13 years. J Am Coll Cardiol 2000; 36:1371-7. [PMID: 11028497 DOI: 10.1016/s0735-1097(00)00862-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVES This study sought to determine the diagnostic accuracy and impact of the systematic use of coronary echocardiography in a large group of preoperative patients with tetralogy of Fallot (TOF). BACKGROUND Accurate preoperative identification of an anomalous coronary artery crossing the right ventricular outflow tract (RVOT) in patients with TOF is important to prevent coronary injury during surgical repair. METHODS A retrospective review identified 598 patients with TOF between 1983 to 1995 who underwent an echocardiogram at <2 years old before complete surgical repair. Associated diagnoses included pulmonary stenosis (n = 433), pulmonary atresia (n = 121), common atrioventricular canal (n = 17), absent pulmonary valve syndrome (n = 24) and aortopulmonary window (n = 3). RESULTS Based on intraoperative findings, 32 patients (5.4%) were found to have a major coronary artery crossing the RVOT. The use and diagnostic performance of coronary echocardiography increased over time, while the number of patients undergoing preoperative cardiac catheterization declined. During the most recent study period (1991 to 1995, n = 274), 97% of patients underwent coronary echocardiography yielding a sensitivity of 82%, specificity of 99% and accuracy of 98.5%. Of the 18 patients with TOF and pulmonary stenosis who had abnormal coronary arteries during this period, only 6 (33%) required an extracardiac conduit as part of their complete repair. CONCLUSIONS Coronary echocardiography is an accurate noninvasive tool to delineate coronary anatomy in infants with TOF before complete repair. Routine preoperative cardiac catheterization solely for diagnosis of coronary anatomy is not necessary. The use of an extracardiac conduit can be avoided in the majority of patients with TOF and pulmonary stenosis who have a major coronary artery crossing the RVOT.
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Affiliation(s)
- L R Need
- Department of Cardiology, Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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14
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Abstract
BACKGROUND Gadolinium-enhanced three-dimensional (3D) MR angiography is a useful imaging technique for patients with congenital heart disease. OBJECTIVE This study sought to determine the added value of creating 3D shaded surface displays compared to standard maximal intensity projection (MIP) and multiplanar reformatting (MPR) techniques when analyzing 3D MR angiography data. MATERIALS AND METHODS Seventeen patients (range, 3 months to 51 years old) with a variety of congenital cardiovascular defects underwent gadolinium-enhanced 3D MR angiography of the thorax. Color-coded 3D shaded surface models were rendered from the image data using manual segmentation and computer-based algorithms. Models could be rotated, translocated, or zoomed interactively by the viewer. Information available from the 3D models was compared to analysis based on viewing standard MIP/ MPR displays. RESULTS Median postprocessing time for the 3D models was 6 h (range, 3-25 h) compared to approximately 20 min for MIP/MPR viewing. No additional diagnostic information was gained from 3D model analysis. All major findings with MIP/MPR postprocessing were also apparent on the 3D models. Qualitatively, the 3D models were more easily interpreted and enabled adjacent vessels to be distinguished more readily. CONCLUSION Routine use of 3D shaded surface reconstructions for visualization of contrast enhanced MR angiography in congenital heart disease cannot be recommended. 3D surface rendering may be more useful for presenting complex anatomy to an audience unfamiliar with congenital heart disease and as an educational tool.
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Affiliation(s)
- S Okuda
- Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts, USA
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15
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Whitaker WR, Clare JJ, Powell AJ, Chen YH, Faull RL, Emson PC. Distribution of voltage-gated sodium channel alpha-subunit and beta-subunit mRNAs in human hippocampal formation, cortex, and cerebellum. J Comp Neurol 2000; 422:123-39. [PMID: 10842222 DOI: 10.1002/(sici)1096-9861(20000619)422:1<123::aid-cne8>3.0.co;2-x] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The distribution of mRNAs encoding voltage-gated sodium channel alpha subunits (I, II, III, and VI) and beta subunits (beta1 and beta2) was studied in selected regions of the human brain by Northern blot and in situ hybridisation experiments. Northern blot analysis showed that all regions studied exhibited heterogenous expression of sodium channel transcripts. In situ hybridisation experiments confirmed these findings and revealed a predominantly neuronal distribution. In the parahippocampal gyrus, subtypes II and VI and the beta-subunit mRNAs exhibited robust expression in the granule cells of the dentate gyrus and pyramidal cell layer of the hippocampus. Subtypes I and III showed moderate expression in granule cells and low expression in the pyramidal cell layer. Distinct expression patterns were also observed in the cortical layers of the middle frontal gyrus and in the entorhinal cortex. In particular, all subtypes exhibited higher levels of expression in cortical layers III, V, and VI compared with layers I and II. All subtypes were expressed in the granular layer of the cerebellum, whereas specific expression of subtypes I, VI, beta1, and beta2 mRNAs was observed in Purkinje cells. Subtypes I, VI, and beta1 mRNAs were expressed, at varying levels, in the pyramidal cells of the deep cerebellar nuclei. These data indicate that, as in rat, human brain sodium channel mRNAs have a distinct regional distribution, with individual cell types expressing different compliments of sodium channels. The differential distribution of sodium channel subtypes suggest that they have distinct roles that are likely to be of paramount importance in maintaining the functional heterogeneity of central nervous system neurons.
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Affiliation(s)
- W R Whitaker
- Department of Neurobiology, The Babraham Institute, Babraham, Cambridge CB2 4AT, United Kingdom
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16
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Powell AJ, Chung T, Landzberg MJ, Geva T. Accuracy of MRI evaluation of pulmonary blood supply in patients with complex pulmonary stenosis or atresia. Int J Card Imaging 2000; 16:169-74. [PMID: 11144770 DOI: 10.1023/a:1006486225047] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Detailed imaging of pulmonary artery (PA) anatomy and significant aorto-pulmonary collaterals (APCs) is crucial for surgical planning and follow-up in patients with complex congenital heart disease (CHD) and pulmonary stenosis or atresia. Because examination by echocardiography is often technically limited and catheterization is invasive, this study evaluated the diagnostic accuracy of magnetic resonance imaging (MRI) as an alternate non-invasive tool. Thirteen patients (median age 28 years, range: 1-44 years) underwent both cardiac catheterization and MRI within a median of two months (range 0.1-8 months). Diagnoses included tetralogy of Fallot (TOF) with pulmonary atresia (n = 8), TOF with pulmonary stenosis (n = 2), single left ventricle with pulmonary stenosis (n = 2), and complex heterotaxy with pulmonary stenosis (n = 1). The MRI sequences used in this study were ECG-gated spin echo and gradient echo sequences acquired in multiple planes. Compared to catheterization, MRI had 100% sensitivity and specificity for the diagnosis of main PA (n = 6) and branch PA (n = 13) hypoplasia or stenosis, as well as discontinuous (n = 4) or absent (n = 10) branch PAs. There was complete agreement between catheterization and MRI identification of significant APCs (n = 18). Main PA atresia was noted by MRI in four patients but was not definitively seen by catheterization in any. MRI but not catheterization precisely defined the distance between discontinuous PAs and their relationship to other mediastinal structures. In conclusion, cardiac MRI is a reliable non-invasive imaging modality to define PA and APC anatomy in patients with complex pulmonary stenosis or atresia.
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Affiliation(s)
- A J Powell
- Department of Cardiology, Children's Hospital, Harvard Medical School, Boston, Mass 02115, USA
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17
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Powell AJ, Maier SE, Chung T, Geva T. Phase-velocity cine magnetic resonance imaging measurement of pulsatile blood flow in children and young adults: in vitro and in vivo validation. Pediatr Cardiol 2000; 21:104-10. [PMID: 10754076 DOI: 10.1007/s002469910014] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Quantification of blood flow in vessels provides valuable information that aids management decisions in a variety of cardiac conditions. Current flow measurement techniques are often limited by accuracy, time resolution, convenience, or anatomic localization. This study examined the accuracy of a commercially available phase-velocity cine magnetic resonance imaging (PVC MRI) technique to quantify flow rate in a pulsatile flow phantom. In addition, the equivalence of PVC MRI measurements of pulmonary and systemic flow was evaluated in children and adults without any pathologic shunt. Using a pulsatile flow phantom, volume flow rates measured by PVC MRI were compared to those by a transit-time ultrasound flowmeter over a range of flow rates (1.25-3.5 L/min, 13 trials). Close agreement was found between these techniques (y = 1.02x - 0.02, r = 0.99, Bland-Altman bias = -0.045 L/min, 95% limits of agreement = -0. 19-0.10 L/min). Twenty subjects (median age 12.8 years, range 0.7-49 years) with no pathologic shunt underwent PVC MRI measurement of blood flow in the main pulmonary artery (Q(p)) and the ascending aorta (Q(s)). Data processing time for each location was 20 minutes. The Q(p)/Q(s) ratio closely approximated unity (mean = 0.99, SD = 0. 10, range 0.85-1.19). Interobserver agreement was excellent (Bland-Altman bias = 0.09 L/min, 95% limits of agreement = 0.15-0.33 L/min). PVC MRI is an accurate technique to quantify pulsatile blood flow at a specific location. It can be used to noninvasively calculate Q(p) and Q(s) under normal flow conditions.
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Affiliation(s)
- A J Powell
- Department of Cardiology, Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
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18
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Abstract
Investigation of blood flow in the heart and vessels may provide insight into the function of the cardiovascular system and aid patient management decisions. Phase velocity cine magnetic resonance imaging (PVC MRI) is a powerful and accurate noninvasive technique to quantitate and analyze blood flow. This article describes the principles, performance, and potential limitations of PVC MRI measurements. Clinical applications of PVC MRI are then reviewed with an emphasis on the assessment of congenital heart disease.
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Affiliation(s)
- A J Powell
- Department of Cardiology, Children's Hospital, Boston, MA 02115, USA
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19
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Powell AJ, Darmon AJ, Gonos ES, Lam EW, Peden KW, Jat PS. Different functions are required for initiation and maintenance of immortalization of rat embryo fibroblasts by SV40 large T antigen. Oncogene 1999; 18:7343-50. [PMID: 10602490 DOI: 10.1038/sj.onc.1203154] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We have used two different, but complementary assays to characterize functions of SV40 T antigen that are necessary for its ability to immortalize rat embryo fibroblasts. In accordance with previous work, we found that several functions were required. These include activities that map to the p53 binding domain and the amino terminal 176 amino acids which contain the J domain as well as the CR1 and CR2 domain required for binding and sequestering the RB family of pocket proteins. Moreover, we found that even though activities dependent only upon the amino terminus were sufficient for immortalization they were unable to maintain it. This suggests that immortalization by these amino terminal functions requires either additional events or immortalization of a subset of cells within the heterogeneous rat embryo fibroblast population. We further found that an activity dependent upon amino acids 17 - 27 which remove a portion of the CR1 domain and the predicted alpha-1 helix of the J domain was not necessary to maintain growth but was required for direct immortalization suggesting that at least one of the functions required initially was not required to maintain the immortal state. This represents the first demonstration that some of the functions required for maintenance of the immortal state differ from those required for initiation of immortalization.
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Affiliation(s)
- A J Powell
- Ludwig Institute for Cancer Research, Royal Free and University College School of Medicine, Courtauld Building, 91 Riding House Street, London W1P 8BT, UK
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Geva T, Powell AJ, Crawford EC, Chung T, Colan SD. Evaluation of regional differences in right ventricular systolic function by acoustic quantification echocardiography and cine magnetic resonance imaging. Circulation 1998; 98:339-45. [PMID: 9711939 DOI: 10.1161/01.cir.98.4.339] [Citation(s) in RCA: 172] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Accurate quantitative evaluation of right ventricular (RV) function has been limited by its complex structural geometry. Although embryological and anatomic observations suggest that the RV is composed of 2 distinct components, the RV sinus and infundibulum, most studies on RV dimensions and function viewed it as a single chamber. This study was designed to determine the volumes, relative contribution to global systolic function, and temporal course of contraction and relaxation of the RV sinus and infundibulum. METHODS AND RESULTS Thirty-one individuals without heart disease (aged 1 month to 17 years, 16 boys and 15 girls) participated in this study. Instantaneous area over time, its derivatives, and the temporal course of contraction and relaxation were studied by acoustic quantification echocardiography and phonocardiography in 20 individuals. Global and regional RV volumes and ejection fraction were determined by cine MRI in 11 individuals. The RV sinus made up 81+/-6% of the combined RV end-diastolic volume and 87+/-4% of the combined stroke volume. The infundibulum accounted for the remaining 19+/-6% and 13+/-4%, respectively (P<0.0001). Compared with the infundibulum, the extent of RV sinus fiber shortening was significantly greater: for ejection fraction (56+/-11% versus 38+/-13%, P<0.001), fractional area change (42+/-14% versus 28+/-9%, P<0.0001), and dA/dt (27+/-17% versus 13+/-6%, P<0.0001). Analysis of temporal course of contraction and relaxation (expressed as percentage of the cardiac cycle to adjust for differences in heart rate) showed that the infundibulum follows the RV sinus: onset of contraction 53%+/-14 versus 19+/-11% of systole, time to peak systole 115+/-16% versus 97+/-19% (P< or =0.01), indicating a peristalsis-like pattern of contraction and relaxation. CONCLUSIONS The results of this study demonstrate significant regional differences between the sinus and infundibulum components of the RV with regard to contribution to stroke volume, extent of fiber shortening, and sequence of mechanical activation. These data from normal individuals can be used in future research on RV function in pathological conditions.
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Affiliation(s)
- T Geva
- Department of Cardiology, Children's Hospital, Harvard Medical School, Boston, Mass 02115, USA.
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21
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Abstract
We have exploited a cross-species expression screen to search for cellular immortalizing activities. A newt blastemal cDNA expression library was transfected into rat embryo fibroblasts and immortal cell lines were selected. This identified a 1-kb cDNA fragment which has a low representation in the cDNA library and is derived from the 3'-UTR of an alpha-glucosidase-related mRNA. Expression of this sequence in rat embryo fibroblasts has shown that it is active in promoting colony formation and immortalization. It is also able to cooperate with an immortalization-defective deletion mutant of SV40 T antigen, indicating that it can exert its growth-stimulatory activity in the pathway activated by a viral immortalizing oncogene. This is the first example of an immortalizing activity mediated by an RNA sequence, and further analysis of its mechanism should provide new insights into senescence and immortalization.
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Affiliation(s)
- A J Powell
- Ludwig Institute for Cancer Research, London, United Kingdom
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22
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Abstract
Dollar spot was allowed to develop from natural inoculum in 15 cultivars of creeping bentgrass (Agrostis palustris) until epidemics were well established. At that time, initial disease intensities were assessed, and one-half of each plot was treated with cyproconazole at 0.3 kg a.i./ha. For each cultivar, disease intensities were assessed 6 to 14 days after treatment in both treated and untreated subplots. Three general patterns of recovery were observed: (i) significant recovery only with fungicide treatment; (ii) some recovery without treatment but greater recovery with treatment; and (iii) equal recovery with or without treatment. Only one cultivar exhibited the same recovery pattern in all 3 years; 10 of 15 cultivars exhibited the same pattern in 2 years of testing. In 1991 and 1993, nearly all cultivars tested recovered more quickly when treated with cyproconazole than when left untreated. In contrast, nearly half of the cultivars in 1992 exhibited the same level of recovery in both treated and untreated subplots. Weather conditions during the 1992 test period were cooler and wetter than during the other years of the study, which probably favored host growth and turfgrass recovery. While some cultivars exhibited partial resistance to dollar spot, no consistent association was found among creeping bentgrass cultivars between the level of partial resistance to, and recuperative ability from, dollar spot. Although the recuperative potential of cultivars varies in different environments, the ability to recover quickly from a disease outbreak could be a valuable cultivar attribute, particularly if it can sometimes occur without a curative fungicide application.
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Affiliation(s)
| | | | - A J Powell
- Department of Agronomy, University of Kentucky, Agricultural Science Center-North, Lexington 40546-0091
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23
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Gonos ES, Burns JS, Mazars GR, Kobrna A, Riley TE, Barnett SC, Zafarana G, Ludwig RL, Ikram Z, Powell AJ, Jat PS. Rat embryo fibroblasts immortalized with simian virus 40 large T antigen undergo senescence upon its inactivation. Mol Cell Biol 1996; 16:5127-38. [PMID: 8756670 PMCID: PMC231513 DOI: 10.1128/mcb.16.9.5127] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Introduction of simian virus 40 T antigen into rodent fibroblasts gives rise to cells that can proliferate indefinitely but are dependent upon it for maintenance of their growth once the normal mitotic life span has elapsed. Inactivation of T antigen in these immortalized cells causes rapid and irreversible cessation of growth. To determine whether this growth arrest is associated with entry into senescence, we have undertaken a genetic and biological analysis of conditionally immortal (tsa) cell lines derived by immortalizing rat embryo fibroblasts with the thermolabile tsA58 T antigen. This analysis has identified the following parallels between the tsa cells after inactivation of T antigen and senescent rat embryo fibroblasts: (i) growth arrest is irreversible; (ii) it occurs in G1 as well as G2; (iii) the G1 block can be partially overcome by stimulation with 20% fetal calf serum, but the G2 block cannot be overcome; (iv) 20% fetal calf serum induces c-fos, but c-myc is unaltered; and (v) fibronectin and p21(Waf1/Cip1/Sdi1) are upregulated upon growth arrest. These results suggest that T-antigen-immortalized fibroblasts are committed to undergo senescence but are prevented from undergoing this process by T antigen. Inactivation of T antigen removes this block and results in senescence of the cells. Thus, these cell lines may represent a powerful system for study of the molecular basis of entry into senescence.
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MESH Headings
- Animals
- Antigens, Viral, Tumor/genetics
- Antigens, Viral, Tumor/physiology
- Cattle
- Cell Division
- Cell Line, Transformed
- Cell Transformation, Viral
- Cellular Senescence/physiology
- Cyclin-Dependent Kinase Inhibitor p21
- Cyclins/biosynthesis
- Cyclins/genetics
- DNA Replication
- Embryo, Mammalian/cytology
- Fetal Blood/physiology
- Fibroblasts/cytology
- Fibronectins/biosynthesis
- Fibronectins/genetics
- G1 Phase
- G2 Phase
- Gene Expression Regulation, Viral
- Genes, Immediate-Early
- Genes, fos
- Genes, myc
- Rats
- Rats, Sprague-Dawley
- Simian virus 40/genetics
- Simian virus 40/physiology
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Affiliation(s)
- E S Gonos
- Ludwig Institute for Cancer Research, London, United Kingdom
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Powell AJ, Lyons MK, Rumph JW, Finstuen K. Health risk appraisal and serum cholesterol nutrition education: an outcome study. Mil Med 1996; 161:70-4. [PMID: 8857216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Records of 59 U.S. Army service members identified as at-risk for coronary heart disease were reviewed. Soldiers were divided into groups that completed and did not complete cholesterol nutrition education classes. Differences in the means of repeated cholesterol measures were compared within each group. Results showed statistically significant declines in total cholesterol, with t(35) = 2.94, p < 0.01 for the class completion group and t(22) = 2.18, p < 0.05 for the dropout group. Similar results were noted for low-density lipoprotein measures. However, cholesterol differences in the means between the two groups were not statistically significant. Results indicate that decreases in serum cholesterol may occur due to at-risk reactive behavior, but that full compliance with the current nutrition education program does not appear to further reduce cholesterol levels to any appreciable degree.
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Affiliation(s)
- A J Powell
- U.S. Army-Baylor University Graduate Program in Health Care Administration, Fort Sam Houston, TX 78234-6135, USA
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25
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Abstract
BACKGROUND Right ventricle-to-pulmonary artery (RV-PA) homografts and bioprosthetic conduits are commonly used to palliate various types of complex congenital heart disease. These conduits frequently develop progressive obstruction and require surgical replacement. This report reviews our experience implanting balloon-expandable stents to relieve conduit obstruction and delay reoperation. METHODS AND RESULTS A retrospective review identified 44 patients who underwent placement of 48 stents in obstructed RV-PA conduits. Median patient age was 6.9 years (range, 7 months to 30 years), and median follow-up time was 14.2 months (range, 0 to 48 months). Stent implantation initially decreased the RV-PA pressure gradient from 61.0 +/- 16.9 to 29.7 +/- 11.9 mm Hg (P < or = .001) and the right ventricular-to-systemic arterial pressure ratio from 0.92 +/- 0.17 to 0.63 +/- 0.20 (P < or = .001). The diameter of the stenotic region expanded from 9.3 +/- 3.5 to 12.3 +/- 3.3 mm in the anteroposterior view (P < or = .001) and from 6.6 +/- 2.9 to 10.9 +/- 2.5 mm in the lateral view (P < or = .001). During the follow-up period, 2 patients had their stents redilated, 7 had additional conduit stents deployed, and 14 underwent surgical replacement of their conduits. Actuarial freedom from conduit reoperation was 65% at 30 months postprocedure. Seven patients were found to have fractured stents on follow-up, suggesting an important role for external compressive forces in conduit failure. Recatheterization in 16 patients a median of 11.8 months (3 to 48 months) postprocedure demonstrated hemodynamic evidence of recurrent obstruction despite sustained enlargement at the previously stented sites. Complications included stent displacement (n = 1), bacterial endocarditis (n = 1), and false aneurysm formation (n = 1). One patient died awaiting conduit replacement surgery. CONCLUSIONS Stent implantation in obstructed RV-PA conduits results in significant immediate hemodynamic and angiographic improvement. In a subgroup of patients, the procedure prolongs conduit life span by several years and increases the interval between conduit reoperations. Recurrent obstruction is caused by external compression and progressive stenosis outside the stented region.
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Affiliation(s)
- A J Powell
- Department of Cardiology, Children's Hospital, Harvard Medical School, Boston, Mass. 02115, USA
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26
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Haub JG, Johnson MJ, Powell AJ, Orr BJ. Bandwidth characteristics of a pulsed optical parametric oscillator: application to degenerate four-wave mixing spectroscopy. Opt Lett 1995; 20:1637-1639. [PMID: 19862108 DOI: 10.1364/ol.20.001637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Factors influencing the optical bandwidth of a free-running pulsed beta-barium borate optical parametric oscillator are examined and incorporated in a simple fitting procedure. Spatiospectral phenomena in the optical parametric oscillator output beam are thereby identified; these suggest a novel way to reduce the effective optical bandwidth for spectroscopic purposes. This technique is demonstrated by recording a degenerate fourwave mixing spectrum of sodium atoms in an air-acetylene flame.
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27
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Potter DA, Spicer PG, Redmond CT, Powell AJ. Toxicity of pesticides to earthworms in Kentucky bluegrass turf. Bull Environ Contam Toxicol 1994; 52:176-181. [PMID: 8123975 DOI: 10.1007/bf00198485] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- D A Potter
- Department of Entomology, University of Kentucky, Lexington 40546-0091
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28
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Abstract
Muscle, bone, and tendon forces; the movement of the center of mass, and the spring properties of the body during terrestrial locomotion can be measured using ground-mounted force platforms. These measurements have been extremely time consuming because of the difficulty in obtaining repeatable constant speed trials (particularly with animals). We have overcome this difficulty by mounting a force platform directly under the belt of a motorized treadmill. With this arrangement, vertical force can be recorded from an unlimited number of successive ground contacts in a much shorter time. With this treadmill-mounted force platform it is possible to accurately make the following measurements over the full range of steady speeds and under various perturbations of normal gait: 1) vertical ground reaction force over the course of the contact phase; 2) peak forces in bone, muscle, and tendon; 3) the vertical displacement of the center of mass; and 4) contact time for the limbs. In our treadmill-force platform design, belt forces and frictional forces cause no measurable cross-talk problem. Natural frequency (160 Hz), nonlinearity (less than 5%), and position independence (less than 2%) are all quite acceptable. Motor-caused vibrations are greater than 150 Hz and thus can be easily filtered.
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Affiliation(s)
- R Kram
- Museum of Comparative Zoology, Harvard University, Bedford, Massachusetts 01730
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29
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Powell AJ, Peace GW, Slabas AR, Lloyd CW. The detergent-resistant cytoskeleton of higher plant protoplasts contains nucleus-associated fibrillar bundles in addition to microtubules. J Cell Sci 1982; 56:319-35. [PMID: 6762377 DOI: 10.1242/jcs.56.1.319] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytoskeletons prepared from carrot protoplasts often retain the nucleus, which is associated with bundles of 7 nm fibrils. These were also seen in cytoskeletons from oil palm, maize and Italian rye grass cells. By examining such cytoskeletons by immunofluorescence, negative staining and stereo scanning electron microscopy it appears that the bundles could be part of a more delicate system of fibrils distal to the nucleus. Optical diffraction of the bundles, staining with heavy meromyosin, drug treatments and phalloidin-staining all confirm that the bundles are not composed of actin. Bundles could not be isolated from such cytoskeletons in quantities sufficient for analysis, but by disrupting protoplasts prepared from stationary-phase cells it was possible to purify fibrillar bundles that appeared in the lysate. These were similar in size and properties to the nucleus-associated bundles. The former were shown by sodium dodecyl sulphate/polyacrylamide gel electrophoresis to be composed of several proteins and were sensitive to reducing agents. Since they are not composed of actin, the possibility was explored that these fibrils are related to the P-proteins of phloem sieve tube and accessory cells.
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30
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31
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Lloyd CW, Slabas AR, Powell AJ, Lowe SB. Microtubules, protoplasts and plant cell shape : An immunofluorescent study. Planta 1980; 147:500-506. [PMID: 24311175 DOI: 10.1007/bf00380194] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/1979] [Accepted: 09/19/1979] [Indexed: 06/02/2023]
Abstract
Indirect immunofluorescence has been used to study the function of cytoplasmic microtubules in controlling the shape of elongated carrot cells in culture. Using a purified wall-degrading preparation, the elongated cells are converted to spherical protoplasts and the transverse hoops of bundled microtubules are disorganised but not depolymerised in the process. Since microtubules remain attached to fragments of protoplast membrane adhering to coverslips and are still seen to be organised laterally in bundles, it would appear that re-orientation of the transverse bundles is due to loss of cell wall and not to the cleavage of microtubule bridges. After 24 h treatment in 10(-3) M colchicine, microtubules are depolymerised in elongated cells but, at this time, the cells retain their elongated shape. This suggests that wall which was organised in the presence of transverse microtubule bundles can retain asymmetric shape for short periods in the absence of those tubules. However, after longer periods of time the cells become spherical in colchicine. Neither wall nor tubules therefore exert individual control on continued cellular elongation and so we emphasize the fundamental nature of wall/microtubule interactions in shape control. It is concluded that the observations are best explained by a model in which hooped bundles of microtubules-which are directly or indirectly associated with molecules involved with cellulose biosynthesis at the cell surface-act as an essential template or scaffolding for the orientated deposition of cellulose.
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Affiliation(s)
- C W Lloyd
- Biosciences Division, Unilever Research, Sharnbrook, Bedford, U.K
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Slabas AR, Powell AJ, Lloyd CW. An improved procedure for the isolation and purification of protoplasts from carrot suspension culture. Planta 1980; 147:283-286. [PMID: 24311076 DOI: 10.1007/bf00379834] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/1979] [Accepted: 08/30/1979] [Indexed: 06/02/2023]
Abstract
A procedure is reported for the rapid and highly reproducible isolation of protoplasts from carrot suspension culture. The method utilizes Onozuka R 10 cellulase which has been purified by chromatography on Sephadex G75. Protoplast isolation, using this procedure, is quantitative and complete within 1 to 1.5 h. Intact protoplasts were separated from broken ones and other cellular debris by application of a polyethylene glycol/dextran two-phase system. The protoplasts isolated in this manner lack any detectable cell wall and are greater than 95% viable when assayed using fluorescein diacetate. It is concluded that such protoplasts are highly suitable for biochemical studies.
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Affiliation(s)
- A R Slabas
- Biosciences Division, Unilever Research, Colworth House, Sharnbrook, MK44 1LQ, Bedford, UK
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Thom D, Powell AJ, Rees DA. Mechanisms of cellular adhesion. IV. Role of serum glycoproteins in fibroblast spreading on glass. J Cell Sci 1979; 35:281-305. [PMID: 106061 DOI: 10.1242/jcs.35.1.281] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have investigated the exogenous factors required for the transition from the round shape of suspended fibroblasts to the characteristic spread shape on serum-coated glass. Following the evidence of others that the transition is facilitated by adsorbed component(s) related to CIG/LETS (cold-insoluble globulin/large external transformation-sensitive) proteins, we have isolated 2 such preparations from chick serum. Their influence has been investigated on fibroblast adhesion, spreading and growth and they have been characterized by gel electrophoresis, immunological cross-reactivity, amino acid and carbohydrate residue analysis, sedimentation velocity behaviour and circular dichroism spectroscopy. The preparations have molecular weights of 225/215,000 and 140,000 Daltons respectively and are closely similar in composition and secondary structure. The 225/215 000 Dalton doublet is probably a product of limited proteolysis which almost certainly occurred in the avian circulation. For cells seeded on glass precoated in different ways and in different supplemented media we could detect no change in the extent of attachment but there were profound influences on cell shape following this initial adhesion. We confirm that prior adsorption of either CIG-related preparation to glass does indeed promote fibroblast spreading in the absence of other serum components and that CIG is the sole serum component with this type of activity. We now add 2 important qualifications: (i) the presence of substrate-adsorbed serum CIG is not essential for spreading when other serum components are present in the medium; and (ii) the adhesive organization shown by interference reflexion microscopy is incompletely formed unless the additional serum components are present in the medium. We therefore conclude that 16C fibroblasts have the ability when given the stimulus of soluble serum components other than CIG, but not otherwise, to synthesize all the components necessary for the highly organized contacts with glass, including endogenous CIG/LETS proteins.
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Abstract
1. A method was developed which allows the rapid preparation of pure plasma membranes in high yield from cultured fibroblasts. 2. Cells are lysed in hypo-osmotic borate/EDTA and, after differential centrifugation, the membranes collected by centrifugation on a sucrose barrier. 3. Electron microscopy of the isolated material shows large membrane vesicles essentially free from contaminating organelles. 4. There is no detectable activity of the endoplasmic-reticulum enzyme marker, NADH2--lipoamide oxidoreductase (EC 1.6.4.3), and that of succinate dehydrogenase (EC 1.3.99.1), a marker for mitochondria, is substantially decreased. Chemical compositions are in good agreement with previous observations. 5. This study confirms the usefulness of applied isotopic markers for isolating plasma membranes.
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Parr DM, Connell GE, Powell AJ, Pruzanski W. A pathologic IgM occurring in serum as pentamer, dimer, and monomer. J Immunol 1974; 113:2020-6. [PMID: 4214870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Vorísek J, Powell AJ, Vanĕk Z. Regulation of biosynthesis of secondary metabolites. 13. Specific allosteric properties of phosphoenolpyruvate carboxylase in Streptomyces aureofaciens. Folia Microbiol (Praha) 1970; 15:153-9. [PMID: 5469695 DOI: 10.1007/bf02873078] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Powell AJ, Stevens T, McCully KA. Effects of commercial processing on residues of aldrin and dieldrin in tomatoes and residues in subsequent crops grown on the treated plots. J Agric Food Chem 1970; 18:224-227. [PMID: 5524475 DOI: 10.1021/jf60168a025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Vorísek J, Powell AJ, Vanĕk Z. Regulation of biosynthesis of secondary metabolites. IV. Purification and properties of phosphoenolpyruvate carboxylase in Streptomyces aureofaciens. Folia Microbiol (Praha) 1969; 14:398-405. [PMID: 5820752 DOI: 10.1007/bf02872709] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Bu'Lock JD, Hamilton D, Hulme MA, Powell AJ, Smalley HM, Shepherd D, Smith GN. Metabolic development and secondary biosynthesis in Penicillium urticae. Can J Microbiol 1965; 11:765-78. [PMID: 5883889 DOI: 10.1139/m65-104] [Citation(s) in RCA: 82] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
In cultures of Penicillium urticae Bainier, two successive physiological phases are distinguished. In the first, or trophophase, mycelial N, P, RNA, and —SH and the utilization of acetate for synthesis reach maximum values while glucose oxidation, mainly by the hexose monophosphate pathway, is most rapid. In the second, or idiophase, assimilation of N and P is reduced, RNA and —SH levels are lower, glucose is oxidized more slowly and mainly by glycolysis, fatty acids or mannitol accumulate, and special phenolic metabolites derived from 6-methyl-salicylic acid appear. The phase transition occurs sharply, with a minimum of respiratory activity and of acetate utilization; thereafter the pattern of secondary metabolism is established in a stepwise manner. The observations are interpreted in terms of sequential enzyme induction initiated by metabolic dislocation, and the generalized applications of such an hypothesis are considered.
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