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Ravindran S, Underwood SL, Dorrens J, Seeker LA, Watt K, Wilbourn RV, Sparks AM, Sinclair R, Chen Z, Pilkington JG, McNeilly TN, Harrington L, Pemberton JM, Nussey DH, Froy H. No correlative evidence of costs of infection or immunity on leucocyte telomere length in a wild population of Soay sheep. Proc Biol Sci 2024; 291:20232946. [PMID: 38565156 PMCID: PMC10987235 DOI: 10.1098/rspb.2023.2946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/04/2024] [Indexed: 04/04/2024] Open
Abstract
Telomere length (TL) is a biomarker hypothesized to capture evolutionarily and ecologically important physiological costs of reproduction, infection and immunity. Few studies have estimated the relationships among infection status, immunity, TL and fitness in natural systems. The hypothesis that short telomeres predict reduced survival because they reflect costly consequences of infection and immune investment remains largely untested. Using longitudinal data from a free-living Soay sheep population, we tested whether leucocyte TL was predicted by infection with nematode parasites and antibody levels against those parasites. Helminth parasite burdens were positively associated with leucocyte TL in both lambs and adults, which is not consistent with TL reflecting infection costs. We found no association between TL and helminth-specific IgG levels in either young or old individuals which suggests TL does not reflect costs of an activated immune response or immunosenescence. Furthermore, we found no support for TL acting as a mediator of trade-offs between infection, immunity and subsequent survival in the wild. Our results suggest that while variation in TL could reflect short-term variation in resource investment or environmental conditions, it does not capture costs of infection and immunity, nor does it behave like a marker of an individual's helminth-specific antibody immune response.
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Affiliation(s)
- Sanjana Ravindran
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Sarah L. Underwood
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Jennifer Dorrens
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Luise A. Seeker
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Kathryn Watt
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Rachael V. Wilbourn
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Alexandra M. Sparks
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Rona Sinclair
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Zhulin Chen
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Jill G. Pilkington
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Tom N. McNeilly
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK
| | - Lea Harrington
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada H3C 3J7
| | - Josephine M. Pemberton
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Daniel H. Nussey
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Hannah Froy
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
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McKenna-Ell C, Ravindran S, Pilkington JG, Pemberton JM, Nussey DH, Froy H. Trait-dependent associations between early- and late-life reproduction in a wild mammal. Biol Lett 2023; 19:20230050. [PMID: 37433328 DOI: 10.1098/rsbl.2023.0050] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 06/23/2023] [Indexed: 07/13/2023] Open
Abstract
Early- versus late-life trade-offs are a central prediction of life-history theory that are expected to shape the evolution of ageing. While ageing is widely observed in wild vertebrates, evidence that early-late trade-offs influence ageing rates remains limited. Vertebrate reproduction is a complex, multi-stage process, yet few studies have examined how different aspects of early-life reproductive allocation shape late-life performance and ageing. Here, we use longitudinal data from a 36-year study of wild Soay sheep to show that early-life reproduction predicts late-life reproductive performance in a trait-dependent manner. Females that started breeding earlier showed more rapid declines in annual breeding probability with age, consistent with a trade-off. However, age-related declines in offspring first-year survival and birth weight were not associated with early-life reproduction. Selective disappearance was evident in all three late-life reproductive measures, with longer-lived females having higher average performance. Our results provide mixed support for early-late reproductive trade-offs and show that the way early-life reproduction shapes late-life performance and ageing can differ among reproductive traits.
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Affiliation(s)
- Chris McKenna-Ell
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Sanjana Ravindran
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Jill G Pilkington
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Josephine M Pemberton
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Daniel H Nussey
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Hannah Froy
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
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Ravindran S, Froy H, Underwood SL, Dorrens J, Seeker LA, Watt K, Wilbourn RV, Pilkington JG, Harrington L, Pemberton JM, Nussey DH. The association between female reproductive performance and leukocyte telomere length in wild Soay sheep. Mol Ecol 2022; 31:6184-6196. [PMID: 34514660 DOI: 10.1111/mec.16175] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 08/03/2021] [Indexed: 01/31/2023]
Abstract
Telomere length (TL), typically measured across a sample of blood cells, has emerged as an exciting potential marker of physiological state and of the costs of investment in growth and reproduction within evolutionary ecology. While there is mounting evidence from studies of wild vertebrates that short TL predicts raised subsequent mortality risk, the relationship between reproductive investment and TL is less clear cut, and previous studies report both negative and positive associations. In this study, we examined the relationship between TL and different aspects of maternal reproductive performance in a free-living population of Soay sheep. We find evidence for shorter TL in females that bred, and thus paid any costs of gestation, compared to females that did not breed. However, we found no evidence for any association between TL and litter size. Furthermore, females that invested in gestation and lactation actually had longer TL than females who only invested in gestation because their offspring died shortly after birth. We used multivariate models to decompose these associations into among- and within-individual effects, and discovered that within-individual effects were driving both the negative association between TL and gestation, and the positive association between TL and lactation. This suggests that telomere dynamics may reflect recent physiologically costly investment or variation in physiological condition, depending on the aspect of reproduction being investigated. Our results highlight the physiological complexity of vertebrate reproduction, and the need to better understand how and why different aspects of physiological variation underpinning life histories impact blood cell TL.
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Affiliation(s)
- Sanjana Ravindran
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Hannah Froy
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.,Centre for Biodiversity Dynamics, Institute for Biology, Norwegian University for Science and Technology (NTNU), Trondheim, Norway
| | - Sarah L Underwood
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Jennifer Dorrens
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Luise A Seeker
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Kathryn Watt
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Rachael V Wilbourn
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Jill G Pilkington
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Lea Harrington
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Josephine M Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Daniel H Nussey
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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Mahendra Raj S, Ravindran S, Kaur M, Braganza MC, Kunnath AP. Duodenal eosinophilia is associated with symptomatic erosive gastro-oesophageal reflux disease, presence of co-morbidities, and ethnicity but not undifferentiated functional dyspepsia: A retrospective Malaysian study. Med J Malaysia 2022; 77:494-499. [PMID: 35902941] [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] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
BACKGROUND Duodenal eosinophilia is postulated to play a key role in the pathogenesis of functional dyspepsia, a common condition responsible for considerable impairment of quality of life. Our objective was to evaluate the relative strength of the associations between duodenal eosinophilia, functional dyspepsia, symptomatic erosive gastroesophageal reflux disease (GERD), the presence of co-morbidities, and a number of other variables. METHODS Eosinophil counts of archived endoscopic duodenal biopsies of 289 subjects were determined by a pathologist blinded to the clinical data. Duodenal eosinophilia was defined by a count of more than 15 per 5 high power fields. Clinical charts were reviewed by a gastroenterologist blinded to the histology review. RESULTS In the study sample, the primary diagnosis was functional dyspepsia (undifferentiated by subtypes) in 45, symptomatic erosive GERD in 29, gall stone disease in 17, irritable bowel syndrome in 23, and an alternative or undetermined diagnosis in 175 subjects, respectively. On logistic regression analyses, eosinophil counts were positively associated with symptomatic erosive GERD (Odds Ratio, OR 1.03, 95% Confidence Interval, 95%CI: 1.00, 1.05; p=0.035) but not functional dyspepsia. Pre-defined duodenal eosinophilia was associated with symptomatic erosive gastro-oesophageal reflux disease (OR 3.36, 95%CI 1.18,-9.60; p=0.023), the presence of co-morbidities (OR 2.00, 95%CI 1.10, 3.62; p=0.022), and Chinese (as compared to Malay and Indian) ethnicity but not with either functional dyspepsia, irritable bowel syndrome, gallstone disease, Helicobacter pylori infection, or gender. CONCLUSION Duodenal eosinophilia was associated with symptomatic erosive GERD, the presence of co-morbidities, and Chinese ethnicity but not with undifferentiated functional dyspepsia.
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Affiliation(s)
- S Mahendra Raj
- Pantai Hospital Kuala Lumpur, Department of Medicine, Kuala Lumpur Malaysia.
| | - S Ravindran
- Pantai Hospital Kuala Lumpur, Pantai Premier Pathology, Kuala Lumpur Malaysia
| | - M Kaur
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
| | - M C Braganza
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
| | - A P Kunnath
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
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Mahendra Raj S, Ravindran S, Braganza MC, Kaur K, Kunnath AP. A retrospective audit of endoscopic duodenal biopsies to uncover undetected Coeliac disease in Malaysian patients. Med J Malaysia 2021; 76:811-813. [PMID: 34806665] [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] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
BACKGROUND Coeliac disease, an autoimmune enteropathy related to gluten sensitivity was hitherto thought to be rare in Asia. Recent data however suggests that Celiac disease may be under-diagnosed in Asia. OBJECTIVE The aim of this audit was to determine the frequency of histological changes compatible with Coeliac disease among patients undergoing elective diagnostic oesaphago-gastro-duodenoscopy (OGDS) under the care of a single practitioner in a Malaysian hospital. MATERIALS AND METHODS The archived endoscopically obtained duodenal biopsy specimens of 241 consecutive Malaysian subjects undergoing elective diagnostic (OGDS) were reviewed by a pathologist blinded to the clinical data. Based on intra-epithelial lymphocyte counts, crypt hyperplasia and villous atrophy, each subject was assigned to one of the categories of the Modified Marsh classification for the histological diagnosis of Coeliac disease. The clinical charts of all subjects were reviewed by a single gastroenterologist blinded to the findings of the histological review. RESULTS Of the 241 study subjects, 132 (54.8%) were females. There were 56 (23.2%) Malays, 90 (37.3%) Chinese, 88 (36.5%) Indians and seven (2.9%) from the other category. The median age of the study sample was 49 years (range 15- 88 years). The OGDS was done as part of screening in 15(6.2%) subjects while in the remaining it was part of the investigation of a clinical problem. Based on histological findings, none of the subjects could be assigned to a modified Marsh class of >1. The prevalence of histological changes compatible with Coeliac disease in the study was 0% (binomial exact one-sided 97.5 % confidence interval 0- 1.52%). CONCLUSION In conclusion, this audit provides no evidence that active Coeliac disease is significantly under-detected among symptomatic patients presenting for diagnostic OGDS. The possibility that a significant number may have potential coeliac disease cannot be excluded.
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Affiliation(s)
- S Mahendra Raj
- Pantai Hospital Kuala Lumpur, Department of Medicine, Malaysia.
| | - S Ravindran
- Pantai Hospital Kuala Lumpur, Pantai Premier Pathology, Malaysia
| | - M C Braganza
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
| | - K Kaur
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
| | - A P Kunnath
- International Medical University, School of Health Sciences, Division of Applied Biomedical Science and Biotechnology, Bukit Jalil, Kuala Lumpur, Malaysia
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7
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Wallace MA, Coffman KA, Gilbert C, Ravindran S, Albery GF, Abbott J, Argyridou E, Bellosta P, Betancourt AJ, Colinet H, Eric K, Glaser-Schmitt A, Grath S, Jelic M, Kankare M, Kozeretska I, Loeschcke V, Montchamp-Moreau C, Ometto L, Onder BS, Orengo DJ, Parsch J, Pascual M, Patenkovic A, Puerma E, Ritchie MG, Rota-Stabelli O, Schou MF, Serga SV, Stamenkovic-Radak M, Tanaskovic M, Veselinovic MS, Vieira J, Vieira CP, Kapun M, Flatt T, González J, Staubach F, Obbard DJ. The discovery, distribution, and diversity of DNA viruses associated with Drosophila melanogaster in Europe. Virus Evol 2021; 7:veab031. [PMID: 34408913 PMCID: PMC8363768 DOI: 10.1093/ve/veab031] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Drosophila melanogaster is an important model for antiviral immunity in arthropods, but very few DNA viruses have been described from the family Drosophilidae. This deficiency limits our opportunity to use natural host-pathogen combinations in experimental studies, and may bias our understanding of the Drosophila virome. Here, we report fourteen DNA viruses detected in a metagenomic analysis of 6668 pool-sequenced Drosophila, sampled from forty-seven European locations between 2014 and 2016. These include three new nudiviruses, a new and divergent entomopoxvirus, a virus related to Leptopilina boulardi filamentous virus, and a virus related to Musca domestica salivary gland hypertrophy virus. We also find an endogenous genomic copy of galbut virus, a double-stranded RNA partitivirus, segregating at very low frequency. Remarkably, we find that Drosophila Vesanto virus, a small DNA virus previously described as a bidnavirus, may be composed of up to twelve segments and thus represent a new lineage of segmented DNA viruses. Two of the DNA viruses, Drosophila Kallithea nudivirus and Drosophila Vesanto virus are relatively common, found in 2 per cent or more of wild flies. The others are rare, with many likely to be represented by a single infected fly. We find that virus prevalence in Europe reflects the prevalence seen in publicly available datasets, with Drosophila Kallithea nudivirus and Drosophila Vesanto virus the only ones commonly detectable in public data from wild-caught flies and large population cages, and the other viruses being rare or absent. These analyses suggest that DNA viruses are at lower prevalence than RNA viruses in D.melanogaster, and may be less likely to persist in laboratory cultures. Our findings go some way to redressing an earlier bias toward RNA virus studies in Drosophila, and lay the foundation needed to harness the power of Drosophila as a model system for the study of DNA viruses.
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Affiliation(s)
- Megan A Wallace
- The European Drosophila Population Genomics Consortium (DrosEU)
- Ashworth Laboratories, Institute of Evolutionary Biology, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
| | - Kelsey A Coffman
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Clément Gilbert
- The European Drosophila Population Genomics Consortium (DrosEU)
- Université Paris-Saclay, CNRS, IRD, UMR Évolution, Génomes, Comportement et Écologie, 91198 Gif-sur-Yvette, France
| | - Sanjana Ravindran
- Ashworth Laboratories, Institute of Evolutionary Biology, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
| | - Gregory F Albery
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Jessica Abbott
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Biology, Section for Evolutionary Ecology, Lund University, Sölvegatan 37, Lund 223 62, Sweden
| | - Eliza Argyridou
- The European Drosophila Population Genomics Consortium (DrosEU)
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg, Germany
| | - Paola Bellosta
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Cellular, Computational and Integrative Biology, CIBIO University of Trento, Via Sommarive 9, Trento 38123, Italy
- Department of Medicine & Endocrinology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016, USA
| | - Andrea J Betancourt
- The European Drosophila Population Genomics Consortium (DrosEU)
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Hervé Colinet
- The European Drosophila Population Genomics Consortium (DrosEU)
- UMR CNRS 6553 ECOBIO, Université de Rennes1, Rennes, France
| | - Katarina Eric
- The European Drosophila Population Genomics Consortium (DrosEU)
- Institute for Biological Research “Sinisa Stankovic”, National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, Belgrade, Serbia
| | - Amanda Glaser-Schmitt
- The European Drosophila Population Genomics Consortium (DrosEU)
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg, Germany
| | - Sonja Grath
- The European Drosophila Population Genomics Consortium (DrosEU)
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg, Germany
| | - Mihailo Jelic
- The European Drosophila Population Genomics Consortium (DrosEU)
- Faculty of Biology, University of Belgrade, Studentski trg 16, Belgrade, Serbia
| | - Maaria Kankare
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Biological and Environmental Science, University of Jyväskylä, Finland
| | - Iryna Kozeretska
- The European Drosophila Population Genomics Consortium (DrosEU)
- National Antarctic Scientific Center of Ukraine, 16 Shevchenko Avenue, Kyiv, 01601, Ukraine
| | - Volker Loeschcke
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Biology, Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 116, Aarhus C DK-8000, Denmark
| | - Catherine Montchamp-Moreau
- The European Drosophila Population Genomics Consortium (DrosEU)
- Université Paris-Saclay, CNRS, IRD, UMR Évolution, Génomes, Comportement et Écologie, 91198 Gif-sur-Yvette, France
| | - Lino Ometto
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Biology and Biotechnology, University of Pavia, Pavia 27100, Italy
| | - Banu Sebnem Onder
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Biology, Faculty of Science, Hacettepe University, Ankara, Turkey
| | - Dorcas J Orengo
- The European Drosophila Population Genomics Consortium (DrosEU)
- Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain
| | - John Parsch
- The European Drosophila Population Genomics Consortium (DrosEU)
- Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Planegg, Germany
| | - Marta Pascual
- The European Drosophila Population Genomics Consortium (DrosEU)
- Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain
| | - Aleksandra Patenkovic
- The European Drosophila Population Genomics Consortium (DrosEU)
- Institute for Biological Research “Sinisa Stankovic”, National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, Belgrade, Serbia
| | - Eva Puerma
- The European Drosophila Population Genomics Consortium (DrosEU)
- Departament de Genètica, Microbiologia i Estadística and Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain
| | - Michael G Ritchie
- The European Drosophila Population Genomics Consortium (DrosEU)
- Centre for Biological Diversity, St Andrews University, St Andrews HY15 4SS, UK
| | - Omar Rota-Stabelli
- The European Drosophila Population Genomics Consortium (DrosEU)
- Research and Innovation Center, Fondazione E. Mach, San Michele all’Adige (TN) 38010, Italy
- Centre Agriculture Food Environment, University of Trento, San Michele all’Adige (TN) 38010, Italy
| | - Mads Fristrup Schou
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Biology, Section for Evolutionary Ecology, Lund University, Sölvegatan 37, Lund 223 62, Sweden
- Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Svitlana V Serga
- The European Drosophila Population Genomics Consortium (DrosEU)
- National Antarctic Scientific Center of Ukraine, 16 Shevchenko Avenue, Kyiv, 01601, Ukraine
- Taras Shevchenko National University of Kyiv, 64 Volodymyrska str, Kyiv 01601, Ukraine
| | - Marina Stamenkovic-Radak
- The European Drosophila Population Genomics Consortium (DrosEU)
- Faculty of Biology, University of Belgrade, Studentski trg 16, Belgrade, Serbia
| | - Marija Tanaskovic
- The European Drosophila Population Genomics Consortium (DrosEU)
- Institute for Biological Research “Sinisa Stankovic”, National Institute of Republic of Serbia, University of Belgrade, Bulevar despota Stefana 142, Belgrade, Serbia
| | - Marija Savic Veselinovic
- The European Drosophila Population Genomics Consortium (DrosEU)
- Faculty of Biology, University of Belgrade, Studentski trg 16, Belgrade, Serbia
| | - Jorge Vieira
- The European Drosophila Population Genomics Consortium (DrosEU)
- Instituto de Biologia Molecular e Celular (IBMC), University of Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde, University of Porto, i3S, Porto, Portugal
| | - Cristina P Vieira
- The European Drosophila Population Genomics Consortium (DrosEU)
- Instituto de Biologia Molecular e Celular (IBMC), University of Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde, University of Porto, i3S, Porto, Portugal
| | - Martin Kapun
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Evolutionary Biology and Environmental Studies, University of Zürich, Zürich, Switzerland
- Division of Cell & Developmental Biology, Medical University of Vienna, Vienna, Austria
| | - Thomas Flatt
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Biology, University of Fribourg, Fribourg CH-1700, Switzerland
| | - Josefa González
- The European Drosophila Population Genomics Consortium (DrosEU)
- Institute of Evolutionary Biology (CSIC-UPF), Barcelona, Spain
| | - Fabian Staubach
- The European Drosophila Population Genomics Consortium (DrosEU)
- Department of Evolution and Ecology, University of Freiburg, Freiburg 79104, Germany
| | - Darren J Obbard
- The European Drosophila Population Genomics Consortium (DrosEU)
- Ashworth Laboratories, Institute of Evolutionary Biology, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK
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Lind MI, Ravindran S, Sekajova Z, Carlsson H, Hinas A, Maklakov AA. Experimentally reduced insulin/IGF-1 signaling in adulthood extends lifespan of parents and improves Darwinian fitness of their offspring. Evol Lett 2019; 3:207-216. [PMID: 31007945 PMCID: PMC6457396 DOI: 10.1002/evl3.108] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 02/06/2019] [Indexed: 11/29/2022] Open
Abstract
Classical theory maintains that ageing evolves via energy trade-offs between reproduction and survival leading to accumulation of unrepaired cellular damage with age. In contrast, the emerging new theory postulates that ageing evolves because of deleterious late-life hyper-function of reproduction-promoting genes leading to excessive biosynthesis in late-life. The hyper-function theory uniquely predicts that optimizing nutrient-sensing molecular signaling in adulthood can simultaneously postpone ageing and increase Darwinian fitness. Here, we show that reducing evolutionarily conserved insulin/IGF-1 nutrient-sensing signaling via daf-2 RNA interference (RNAi) fulfils this prediction in Caenorhabditis elegans nematodes. Long-lived daf-2 RNAi parents showed normal fecundity as self-fertilizing hermaphrodites and improved late-life reproduction when mated to males. Remarkably, the offspring of daf-2 RNAi parents had higher Darwinian fitness across three different genotypes. Thus, reduced nutrient-sensing signaling in adulthood improves both parental longevity and offspring fitness supporting the emerging view that suboptimal gene expression in late-life lies at the heart of ageing.
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Affiliation(s)
- Martin I. Lind
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
| | - Sanjana Ravindran
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
| | - Zuzana Sekajova
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
| | - Hanne Carlsson
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
- School of Biological SciencesUniversity of East AngliaNorwichNR4 7TJUnited Kingdom
| | - Andrea Hinas
- Department of Cell and Molecular BiologyUppsala UniversityUppsala751 24Sweden
| | - Alexei A. Maklakov
- Animal Ecology, Department of Ecology and GeneticsUppsala UniversityUppsala752 36Sweden
- School of Biological SciencesUniversity of East AngliaNorwichNR4 7TJUnited Kingdom
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Ravindran S, Williams M, Ward R, Gillies G. Understanding how the properties of whey protein stabilized emulsions depend on pH, ionic strength and calcium concentration, by mapping environmental conditions to zeta potential. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2017.12.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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10
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Ravindran S, Melvani V, Tobin M. P108 Chronic urticaria in the presence of papillary thyroid cancer. Ann Allergy Asthma Immunol 2016. [DOI: 10.1016/j.anai.2016.09.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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11
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Liong CC, Ravindran S, Gnana Kumar G, Chin EF, Koh PS, Chan WK. Enteropathy-associated T-cell lymphoma: An extremely rare cause of chronic diarrhoea. Med J Malaysia 2016; 71:88-90. [PMID: 27326953] [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] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Chronic diarrhoea in tropical countries may be due to a myriad of causes from infective to non-infective. This case report illustrates the challenges faced in the investigation of a middle-age Chinese gentleman who presented with chronic diarrhoea and weight loss. The diagnosis of type II enteropathy-associated T-cell lymphoma (EATL) was finally made. The diagnosis of EATL was least suspected as the condition is almost unheard of in this part of the world. The epidemiology, presentation, diagnosis, management and prognosis of this rare condition are discussed.
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Affiliation(s)
- C C Liong
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia.
| | - S Ravindran
- University of Malaya, Faculty of Medicine, Department of Pathology, Kuala Lumpur, Malaysia
| | - G Gnana Kumar
- University of Malaya, Faculty of Medicine, Department of Biomedical Imaging, Kuala Lumpur, Malaysia
| | - E F Chin
- University of Malaya, Faculty of Medicine, Department of Medicine, Hematology Unit, Kuala Lumpur, Malaysia
| | - P S Koh
- University of Malaya, Faculty of Medicine, Department of Surgery, Kuala Lumpur, Malaysia
| | - W K Chan
- University of Malaya, Faculty of Medicine, Department of Medicine, Gastroenterology and Hepatology Unit, Kuala Lumpur, Malaysia
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Ravindran S, Tessema A, Kidane A. Note: Dynamic meso-scale full field surface deformation measurement of heterogeneous materials. Rev Sci Instrum 2016; 87:036108. [PMID: 27036841 DOI: 10.1063/1.4944488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 03/06/2016] [Indexed: 06/05/2023]
Abstract
A dynamic experiment at mesoscale is developed to measure local deformation and strain in granular materials at high temporal and spatial resolutions. The experimental setup is comprised of a high-speed camera along with a high magnification extension tube. The method is demonstrated by measuring the full field strain across and in the boundary of the crystals at a high temporal resolution in polymer bonded sugar crystals and glass beads filled epoxy particulate composite specimens under dynamic loading. In both cases, the local strain heterogeneity is captured successfully. The measured strain and deformation field can be further used to obtain the relative motion of each crystal, crystal rotation, and the relative displacement between the polymer interface and the crystal, which are very critical to understand the local failure mechanisms in heterogeneous materials.
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Affiliation(s)
- S Ravindran
- Department of Mechanical Engineering, the University of South Carolina, Columbia, South Carolina 28209, USA
| | - A Tessema
- Department of Mechanical Engineering, the University of South Carolina, Columbia, South Carolina 28209, USA
| | - A Kidane
- Department of Mechanical Engineering, the University of South Carolina, Columbia, South Carolina 28209, USA
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Padovano JD, Ravindran S, Snee PT, Ramachandran A, Bedran-Russo AK, George A. DMP1-derived peptides promote remineralization of human dentin. J Dent Res 2015; 94:608-14. [PMID: 25694469 DOI: 10.1177/0022034515572441] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Remineralization of dentin during dental caries is of considerable clinical interest. Dentin matrix protein 1 (DMP1) is a non-collagenous calcium-binding protein that plays a critical role in biomineralization. In the present study, we tested if peptides derived from DMP1 can be used for dentin remineralization. Peptide pA (pA, MW = 1.726 kDa) and peptide pB (pB, MW = 2.185), containing common collagen-binding domains and unique calcium-binding domains, were synthesized by solid-phase chemistry. An extreme caries lesion scenario was created by collagenase digestion, and the biomineral-nucleating potential of these peptides was ascertained when coated on collagenase-treated dentin matrix and control, native human dentin matrix under physiological levels of calcium and phosphate. Scanning electron microscopy analysis suggests that peptide pB was an effective nucleator when compared with pA. However, a 1:4 ratio of pA to pB was determined to be ideal for dentin remineralization, based on hydroxyapatite (HA) morphology and calcium/phosphorus ratios. Interestingly, HA was nucleated on collagenase-challenged dentin with as little as 20 min of 1:4 peptide incubation. Electron diffraction confirmed the presence of large HA crystals that produced a diffraction pattern indicative of a rod-like crystal structure. These findings suggest that DMP1-derived peptides may be useful to modulate mineral deposition and subsequent formation of HA when exposed to physiological concentrations of calcium and phosphate.
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Affiliation(s)
- J D Padovano
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - S Ravindran
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - P T Snee
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - A Ramachandran
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - A K Bedran-Russo
- Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA
| | - A George
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL, USA
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Zhang Y, Song Y, Ravindran S, Gao Q, Huang CC, Ramachandran A, Kulkarni A, George A. DSPP contains an IRES element responsible for the translation of dentin phosphophoryn. J Dent Res 2013; 93:155-61. [PMID: 24352500 DOI: 10.1177/0022034513516631] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The major phosphoprotein in dentin is the aspartic acid and serine-rich protein called dentin phosphophoryn (DPP). DPP appears to be synthesized as a part of a larger compound protein, dentin sialophosphoprotein (DSPP). DSPP has never been isolated or detected in dentin extracts. It is now evident that DSPP is a chimeric protein composed of 3 parts: dentin sialoprotein (DSP), DPP, and dentin glycoprotein (DGP). Previous reports have suggested that the BMP1 protease is responsible for processing DSPP. However, unequal amounts of these products are present in the dentin matrix. Here, we provide evidence for an internal ribosome entry site in the DSPP gene that directs the synthesis of DPP. This mechanism would account for unequal amounts of intracellular DSP and DPP. The internal ribosomal entry site (IRES) activity varied in different cell types, suggesting the presence of additional regulatory elements during the translational regulation of DPP. Further, we provide evidence that DPP is transported to the extracellular matrix (ECM) through exosomes. Using tissue recombination and lentivirus-mediated gain-of-function approaches, we also demonstrate that DPP is essential for the formation of well-defined tooth structures with mineralized dentin matrix.
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Affiliation(s)
- Y Zhang
- Brodie Tooth Development Genetics & Regenerative Medicine Research Laboratory, Department of Oral Biology, University of Illinois at Chicago, Chicago, IL 60612, USA
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Rao SPS, Lakshminarayana SB, Kondreddi RR, Herve M, Camacho LR, Bifani P, Kalapala SK, Jiricek J, Ma NL, Tan BH, Ng SH, Nanjundappa M, Ravindran S, Seah PG, Thayalan P, Lim SH, Lee BH, Goh A, Barnes WS, Chen Z, Gagaring K, Chatterjee AK, Pethe K, Kuhen K, Walker J, Feng G, Babu S, Zhang L, Blasco F, Beer D, Weaver M, Dartois V, Glynne R, Dick T, Smith PW, Diagana TT, Manjunatha UH. Indolcarboxamide Is a Preclinical Candidate for Treating Multidrug-Resistant Tuberculosis. Sci Transl Med 2013; 5:214ra168. [DOI: 10.1126/scitranslmed.3007355] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Padovano J, Ravindran S, Ramachandran A, Bedran-Russo A, George A. Dentin mineralization using DMP1-derived synthetic peptides. Dent Mater 2013. [DOI: 10.1016/j.dental.2013.08.194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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George A, Ramachandran A, Albazzaz M, Ravindran S. DMP1--a key regulator in mineralized matrix formation. J Musculoskelet Neuronal Interact 2007; 7:308. [PMID: 18094486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Affiliation(s)
- A George
- Department of Oral Biology, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Chadwick D, Pido-Lopez J, Pires A, Imami N, Gotch F, Villacian JS, Ravindran S, Paton NI. A pilot study of the safety and efficacy of thymosin alpha 1 in augmenting immune reconstitution in HIV-infected patients with low CD4 counts taking highly active antiretroviral therapy. Clin Exp Immunol 2004; 134:477-81. [PMID: 14632754 PMCID: PMC1808897 DOI: 10.1111/j.1365-2249.2003.02331.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
To study the safety and efficacy of thymosin alpha1 in stimulating immune reconstitution in combination with highly active antiretroviral therapy (HAART), a phase II randomized, controlled open-label trial of subcutaneous thymosin alpha1 was undertaken for 12 weeks. Twenty clinically stable patients with viral loads <400 copies/ml and CD4 counts less than 200 cells/microl were randomized to receive 3.2 mg thymosin alpha 1 subcutaneous injections twice weekly or no injections for 12 weeks. CD4 and CD8 counts, CD45 RO+ and RA+ subsets and signal joint T cell receptor excision circles (sjTREC) in peripheral blood mononuclear cells (PBMCs) were measured every 2 weeks. Thirteen patients received thymosin alpha 1 and seven were controls. Thymosin alpha 1 was well tolerated and there were no serious adverse events. There was no significant difference between the thymosin alpha1 and control groups in CD4, CD8 and CD45 lymphocyte subset changes at week 12; however, PBMC sjTREC levels increased significantly in the thymosin alpha 1-treated patients compared to controls at week 12. In conclusion, the increase in PBMC sjTREC levels in patients taking thymosin alpha1 may represent enhanced immune reconstitution; however, the clinical benefits and long-term consequences remain to be determined.
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Affiliation(s)
- D Chadwick
- Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore
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Abstract
C1-inhibitor is an important inhibitor of plasma kallikrein and C1, but also has inhibitory activity against numerous other plasma proteinases such as plasmin. The relevance of plasmin inhibition by the C1-inhibitor has been debated, with some evidence showing that plasmin causes significant proteolysis of C1-inhibitor. In the present study, we show that C1-inhibitor in its native state will inhibit plasmin without being significantly degraded, in a manner typical of all serpin reactions. However, if C1-inhibitor is in a denatured polymeric state (as can easily occur during storage, or as produced by heating of the native protein), it will be extensively degraded by plasmin. In addition, we show that hydrophobic interaction chromatography is an effective method to remove trace contaminants of inactive C1-inhibitor polymers.
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Affiliation(s)
- E W Brown
- Department of Oral Medicine and Diagnostic Sciences, and Center for Molecular Biology of Oral Diseases, University of Illinois at Chicago, 60612, USA
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Liu S, Gong X, Yan X, Peng T, Baker JC, Li L, Robben PM, Ravindran S, Andersson LA, Cole AB, Roche TE. Reaction Mechanism for Mammalian Pyruvate Dehydrogenase Using Natural Lipoyl Domain Substrates. Arch Biochem Biophys 2001; 386:123-35. [PMID: 11368334 DOI: 10.1006/abbi.2000.2222] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The pyruvate dehydrogenase (E1) component of the pyruvate dehydrogenase complex (PDC) catalyzes a two-step reaction. Recombinant production of substrate amounts of the lipoyl domains of the dihydrolipoyl transacetylase (E2) component of the mammalian PDC allowed kinetic characterization of the rapid physiological reaction catalyzed by E1. Using either the N-terminal (L1) or the internal (L2) lipoyl domain of E2 as a substrate, analyses of steady state kinetic data support a ping pong mechanism. Using standard E1 preparations, Michaelis constants (Km) were 52 +/- 14 microM for L1 and 24.8 +/- 3.8 microM for pyruvate and k(cat) was 26.3 s(-1). With less common, higher activity preparations of E1, the Km values were > or =160 microM for L1 and > or =35 microM for pyruvate and k(cat) was > or =70 s(-1). Similar results were found with the L2 domain. The best synthetic lipoylated-peptide (L2 residues 163-177) was a much poorer substrate (Km > or =15 mM, k(cat) approximately equals 5 s(-1); k(cat)/Km decreased >1,500-fold) than L1 or L2, but a far better substrate in the E1 reaction than free lipoamide (k(cat)/Km increased >500-fold). Each lipoate source was an effective substrate in the dihydrolipoyl dehydrogenase (E3) reaction, but E3 had a lower Km for the L2 domain than for lipoamide or the lipoylated peptides. In contrast to measurements with slow E1 model reactions that use artificial acceptors, we confirmed that the natural E1 reaction, using lipoyl domain acceptors, was completely inhibited (>99%) by phosphorylation of E1 and the phosphorylation strongly inhibited the reverse of the second step catalyzed by E1. The mechanisms by which phosphorylation interferes with E1 activity is interpreted based on accrued results and the location of phosphorylation sites mapped onto the 3-D structure of related alpha-keto acid dehydrogenases.
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Affiliation(s)
- S Liu
- Department of Biochemistry, Kansas State University, Manhattan 66506, USA
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Abstract
BACKGROUND Complete resection of a retroperitoneal sarcoma often requires removal of adjacent organs. In this study we evaluated the role of nephrectomy during operation for retroperitoneal sarcoma. METHODS Between July 1982 and July 1995, 75 of the 371 (20%) patients who underwent resection of retroperitoneal sarcoma at MSKCC underwent concommitant nephrectomy. Data concerning the reasons for nephrectomy, degree of sarcomatous renal involvement, and survival were retrospectively analyzed. RESULTS Fifty-four patients (72%) underwent nephrectomy during the initial resection, and 21 (28%) during a resection of a recurrent or persistent tumor. The most common reason for nephrectomy was total encasement by sarcoma (n = 40; 53%), followed by dense adherence of the tumor to the kidney (n = 21; 28%), and the direct invasion of the kidney by tumor (n = 2; 3%). Pathology demonstrated an absence of kidney invasion in the majority of cases (55 of 75; 73%). Renal capsular invasion was present in 11 of 75 (15%), renal parenchymal invasion in 7 of 75 (9%), and renal vein invasion in 2 of 75 (3%) of cases. There were no significant differences in survival based on degree of sarcoma involvement of the kidney, tumor grade, or whether the resection was for primary or recurrent disease. The 53 patients who underwent a complete gross resection of all tumor had a significantly improved long-term survival compared to the 20 patients who did not (50% versus 20% DFS at 5 years, respectively; p < 0.001). CONCLUSIONS Decisions for concomitant nephrectomy during resection of retroperitoneal sarcoma should be based on whether this maneuver will provide a complete resection of all gross tumor, in which case the long-term disease-free survival of 50% is comparable to the reported 5-year survival of all patients with retroperitoneal sarcoma who are completely resected.
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Affiliation(s)
- P Russo
- Department of Surgery, Memorial Sloan Kettering Cancer Center, New York, New York 10021, USA
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du Preez J, Postma J, Ravindran S, van Brecht B. NITROGEN REAGENTS IN METAL ION SEPARATION. PART 6 2-(r-OCTYLTHIOMETHYL)PYRIDINE AS EXTRACTANT FOR LATER 3d TRANSITION METAL IONS. Solvent Extraction and Ion Exchange 1997. [DOI: 10.1080/07366299708934467] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Ravindran S, Radke GA, Guest JR, Roche TE. Lipoyl domain-based mechanism for the integrated feedback control of the pyruvate dehydrogenase complex by enhancement of pyruvate dehydrogenase kinase activity. J Biol Chem 1996; 271:653-62. [PMID: 8557670 DOI: 10.1074/jbc.271.2.653] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
To conserve carbohydrate reserves, the reaction of the pyruvate dehydrogenase complex (PDC) must be down-regulated when the citric acid cycle is provided sufficient acetyl-CoA. PDC activity is reduced primarily through increased phosphorylation of its pyruvate dehydrogenase (E1) component due to E1 kinase activity being markedly enhanced by elevated intramitochondrial NADH:NAD+ and acetyl-CoA:CoA ratios. A mechanism is evaluated in which enhanced kinase activity is facilitated by the build-up of the reduced and acetylated forms of the lipoyl moieties of the dihydrolipoyl acetyltransferase (E2) component through using NADH and acetyl-CoA in the reverse of the downstream reactions of the complex. Using a peptide substrate, kinase activity was stimulated by these products, ruling out the possibility kinase activity is increased due to changes in the reaction state of its substrate, E1 (thiamin pyrophosphate). Each E2 subunit contains two lipoyl domains, an NH2-terminal (L1) and the inward lipoyl domain (L2), which were individually produced in fully lipoylated forms by recombinant techniques. Although reduction and acetylation of the L1 domain or free lipoamide increased kinase activity, those modifications of the lipoate of the kinase-binding L2 domain gave much greater enhancements of kinase activity. The large stimulation of the kinase generated by acetyl-CoA only occurred upon addition of the transacetylase-catalyzing (lipoyl domain-free) inner core portion of E2 plus a reduced lipoate source, affirming that acetylation of this prosthetic group is an essential mechanistic step for acetyl-CoA enhancing kinase activity. Similarly, the lesser stimulation of kinase activity by just NADH required a lipoate source, supporting the need for lipoate reduction by E3 catalysis. Complete enzymatic delipoylation of PDC, the E2-kinase subcomplex, or recombinant L2 abolished the stimulatory effects of NADH and acetyl-CoA. Retention of a small portion of PDC lipoates lowered kinase activity but allowed stimulation of this residual kinase activity by these products. Reintroduction of lipoyl moieties, using lipoyl protein ligase, restored the capacity of the E2 core to support high kinase activity along with stimulation of that activity up to 3-fold by NADH and acetyl-CoA. As suggested by those results, the enhancement of kinase activity is very responsive to reductive acetylation with a half-maximal stimulation achieved with approximately 20% of free L2 acetylated and, from an analysis of previous results, with acetylation of only 3-6 of the 60 L2 domains in intact PDC. Based on these findings, we suggest that kinase stimulation results from modification of the lipoate of an L2 domain that becomes specifically engaged in binding the kinase. In conclusion, kinase activity is attenuated through a substantial range in response to modest changes in the proportion of oxidized, reduced, and acetylated lipoyl moieties of the L2 domain of E2 produced by fluctuations in the NADH:NAD+ and acetyl-CoA:CoA ratios as translated by the rapid and reversible E3 and E2 reactions.
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Affiliation(s)
- S Ravindran
- Department of Biochemistry, Kansas State University, Manhattan 66506, USA
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Natarajan VS, Ravindran S, Kailash K, Krishnaswamy B, Suresh B, Prabhu P. Assessment of nutrient intake and associated factors in an Indian elderly population. Age Ageing 1993; 22:103-8. [PMID: 8470555 DOI: 10.1093/ageing/22.2.103] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A group of 420 elderly people (163 women and 257 men with a mean age of 65 years) from urban and rural populations in India were selected for the study. The caloric intake of 93.3% was less than the recommended allowance, the mean daily caloric intake being 1191 kcal in men and 928 kcal in women. Except for calcium, all nutrients were deficient in their diet. Illiteracy (53%), lack of knowledge regarding daily allowances of nutrients (95%), poor economic background (46.7%), and breaking down of joint family system (63%) were possible associated factors examined.
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Affiliation(s)
- V S Natarajan
- Department of Geriatric Medicine, Government General Hospital, Madras, Tamil Nadu, India
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Radke GA, Ono K, Ravindran S, Roche TE. Critical role of a lipoyl cofactor of the dihydrolipoyl acetyltransferase in the binding and enhanced function of the pyruvate dehydrogenase kinase. Biochem Biophys Res Commun 1993; 190:982-91. [PMID: 8439347 DOI: 10.1006/bbrc.1993.1146] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mammalian pyruvate dehydrogenase kinase binds to the lipoyl domain region of the core structure forming dihydrolipoyl acetyltransferase (E2) subunits. The bound kinase has a greatly enhanced rate in phosphorylating E2-bound pyruvate dehydrogenase (E1) tetramers versus the rate at which resolved kinase phosphorylates dissociated E1. This E2-activated kinase function was completely prevented by selective alkylation of reduced lipoyl groups while kinase and E1 binding to the E2 core were retained. Selective removal of lipoyl cofactors from intact E2 by treatment with Enterococcus faecalis lipoamidase decreased kinase activity by 4-fold and caused selective release of a major portion of the kinase from E2 in a sucrose-step gradient procedure. Selective and reversible modification of the lipoyl groups of E2 subunits also allowed the kinase to be dissociated under mildly chaotropic conditions. Thus, the lipoyl prosthetic group on one of the two lipoyl domains of E2 subunits is critically important for maintaining E2-activated kinase function and contributes to binding of the kinase to E2. Since removal of the lipoyl group weakened kinase binding to E2 more than modifying lipoyl thiols, it is suggested that the hydrophobic inner portion of the lipoyl conjugate (i.e., lysine carbons and C1 to C5 of the lipoic acid) is important in the binding of the kinase.
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Affiliation(s)
- G A Radke
- Department of Biochemistry, Kansas State University, Manhattan 66506
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Ravindran S. Confronting gender, poverty and powerlessness: an orientation programme for and by rural change agents. Community Dev J 1985; 20:213-221. [PMID: 12315293 DOI: 10.1093/cdj/20.3.213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Rajarajeswari G, Ravindran S, Radhakrishnan S, Viswanathan J. Embryonal rhabdomyosarcoma associated with maternal ingestion of stilboestrol. INDIAN J PATHOL MICR 1979; 22:185-8. [PMID: 489085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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