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Lagunas-Rangel FA. Naked mole-rat hyaluronan. Biochimie 2024; 220:58-66. [PMID: 38158036 DOI: 10.1016/j.biochi.2023.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/21/2023] [Accepted: 12/22/2023] [Indexed: 01/03/2024]
Abstract
Naked mole rats (NMRs) are renowned for their exceptional longevity and remarkable maintenance of health throughout their lifetime. Their subterranean lifestyle has led to adaptations that have resulted in elevated levels of a very high molecular weight hyaluronan in their tissues. Hyaluronan, a glycosaminoglycan, is a key component of the extracellular matrix, which plays a critical role in maintaining tissue structure and regulating cell signaling pathways. This phenomenon in NMRs is attributed to a higher processing and production capacity by some of their hyaluronan synthases, along with lower degradation by certain hyaluronidases. Furthermore, this adaptation indirectly confers several advantages to NMRs, such as the preservation of skin elasticity and youthful appearance, accelerated wound healing, protection against oxidative stress, and resistance to conditions such as cancer and arthritis, largely attributable to CD44 signaling and other intricate mechanisms. Thus, the main objective of this study was to conduct a comprehensive study of the distinctive features of NMR hyaluronan, particularly emphasizing the currently known molecular mechanisms that contribute to its beneficial properties. Furthermore, this research delves into the potential applications of NMR hyaluronan in both cosmetic and therapeutic fields, as well as the challenges involved.
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Affiliation(s)
- Francisco Alejandro Lagunas-Rangel
- Department of Genetics and Molecular Biology, Centro de Investigación y de Estudios Avanzados Del Instituto Politécnico Nacional, Mexico City, Mexico.
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2
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Chua KO, Fatima I, Lau YY, Hong KW, Yin WF, Mardaryev A, Chan KG, Chang CY. Bacterial microbiome of faecal samples of naked mole-rat collected from the toilet chamber. BMC Res Notes 2022; 15:107. [PMID: 35303951 PMCID: PMC8932300 DOI: 10.1186/s13104-022-06000-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/09/2022] [Indexed: 01/04/2023] Open
Abstract
Objective The naked mole rats (NMRs, Heterocephalus glaber) are subterranean rodents that belong to the family Bathyergidae. They gained the attention of the scientific community for their exceptionally long lifespan of up to 30 years and have become an animal model of biomedical research on neurodegenerative diseases, aging and cancer. NMRs dig and survive in a maze of underground tunnels and chambers and demarcate toilet chambers for defecation and urination. Due to their coprophagic behaviours, we believed that the toilet chamber might play a role in maintaining optimal health of the NMRs. A 16S rRNA gene amplicon sequencing was performed to characterize the bacterial microbiome of faecal samples collected from the toilet chamber of a laboratory NMR colony. Results Four faecal samples were collected at different time points from the same toilet chamber of a laboratory NMR colony for analysis. The 16S rRNA gene amplicon sequencing revealed that bacterial phyla Firmicutes and Bacteroidetes were the dominant taxa in the bacterial microbiome of NMRs. The relative abundance of the bacterial taxa shifted substantially between time points, indicating a dynamic microbiome in the toilet chamber. The data provided an insight to the faecal microbiome of NMRs in the toilet chamber. Supplementary Information The online version contains supplementary material available at 10.1186/s13104-022-06000-8.
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Affiliation(s)
- Kah-Ooi Chua
- Centre for Research in Biotechnology for Agriculture, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Iqra Fatima
- Centre for Skin Sciences, School of Chemistry and Biosciences, University of Bradford, Bradford, BD7 1DP, UK
| | - Yin Yin Lau
- Department of Biotechnology, Faculty of Applied Sciences, UCSI University Kuala Lumpur, 56000, Kuala Lumpur, Malaysia
| | - Kar Wai Hong
- International Genome Centre, Jiangsu University, Zhenjiang, China.,Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Wai-Fong Yin
- Institute of Marine Sciences, Shantou University, Shantou, 515063, China
| | - Andrei Mardaryev
- Centre for Skin Sciences, School of Chemistry and Biosciences, University of Bradford, Bradford, BD7 1DP, UK
| | - Kok-Gan Chan
- Department of Biotechnology, Faculty of Applied Sciences, UCSI University Kuala Lumpur, 56000, Kuala Lumpur, Malaysia. .,International Genome Centre, Jiangsu University, Zhenjiang, China. .,Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Chien-Yi Chang
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, NE2 4BW, UK.
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Cooper TK, Meyerholz DK, Beck AP, Delaney MA, Piersigilli A, Southard TL, Brayton CF. Research-Relevant Conditions and Pathology of Laboratory Mice, Rats, Gerbils, Guinea Pigs, Hamsters, Naked Mole Rats, and Rabbits. ILAR J 2022; 62:77-132. [PMID: 34979559 DOI: 10.1093/ilar/ilab022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/12/2021] [Indexed: 12/31/2022] Open
Abstract
Animals are valuable resources in biomedical research in investigations of biological processes, disease pathogenesis, therapeutic interventions, safety, toxicity, and carcinogenicity. Interpretation of data from animals requires knowledge not only of the processes or diseases (pathophysiology) under study but also recognition of spontaneous conditions and background lesions (pathology) that can influence or confound the study results. Species, strain/stock, sex, age, anatomy, physiology, spontaneous diseases (noninfectious and infectious), and neoplasia impact experimental results and interpretation as well as animal welfare. This review and the references selected aim to provide a pathology resource for researchers, pathologists, and veterinary personnel who strive to achieve research rigor and validity and must understand the spectrum of "normal" and expected conditions to accurately identify research-relevant experimental phenotypes as well as unusual illness, pathology, or other conditions that can compromise studies involving laboratory mice, rats, gerbils, guinea pigs, hamsters, naked mole rats, and rabbits.
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Affiliation(s)
- Timothy K Cooper
- Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA
| | - David K Meyerholz
- Department of Pathology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Amanda P Beck
- Department of Pathology, Yeshiva University Albert Einstein College of Medicine, Bronx, New York, USA
| | - Martha A Delaney
- Zoological Pathology Program, University of Illinois at Urbana-Champaign College of Veterinary Medicine, Urbana-Champaign, Illinois, USA
| | - Alessandra Piersigilli
- Laboratory of Comparative Pathology and the Genetically Modified Animal Phenotyping Service, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Teresa L Southard
- Department of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, New York, USA
| | - Cory F Brayton
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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4
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The Unusual Immune System of the Naked Mole-Rat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:315-327. [PMID: 34424522 DOI: 10.1007/978-3-030-65943-1_12] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The immune system plays a critical role in host defense to pathogens, tissue homeostasis, cancer development, and several aging-associated chronic inflammatory diseases. The naked mole-rat (Heterocephalus glaber) is a subterranean rodent with both extraordinary longevity and cancer-resistant phenotypes. Unlike the immune system of standard laboratory rodents, that of the naked mole-rat features a higher myeloid-to-lymphoid ratio, lacks natural killer cells, has higher pro-inflammatory cytokine production in macrophages, and exhibits a novel LPS-responsive neutrophil subset that highly expresses several antimicrobials. Given these unusual features, the potential involvement of the naked mole-rat's immune system in their longevity and cancer-resistance remains enigmatic. In this chapter, we summarize the current knowledge of the immune system in the naked mole-rat, including the immune cell repertoire, the primary and secondary lymphoid organs, and the inflammatory responses to the pathogenic stimulation such as bacterial toxins. We compare these findings to published studies of the other subterranean rodents and discuss how the environmental factors in which they have evolved may have influenced their immune function.
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Smith M, Buffenstein R. Managed Care of Naked Mole-Rats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:381-407. [PMID: 34424526 DOI: 10.1007/978-3-030-65943-1_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Naked mole-rats are a burgeoning model species in the field of biomedical research and are also housed at many zoos throughout the world. These mammals possess many traits that have a large impact on the way that they are kept in captivity such as their eusociality, thermolability and lack of need for drinking water. This chapter outlines the captive care and unusual housing needs of these animals. Providing information and examples from our own experiences while working with naked mole-rats for many decades. While this chapter serves as a good framework for the captive care of this mammal species, it is in no way all-encompassing but simply reflects the way in which we have managed over many years to successfully sustain our colony of thousands of animals.
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Affiliation(s)
- Megan Smith
- Calico Life Sciences LLC, South San Francisco, CA, USA
| | - Rochelle Buffenstein
- Calico Life Sciences LLC, South San Francisco, CA, USA.
- Department of Pharmacology, University of Texas Health at San Antonio, San Antonio, TX, USA.
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6
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Delaney MA, Imai DM, Buffenstein R. Spontaneous Disease and Pathology of Naked Mole-Rats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:353-380. [PMID: 34424525 DOI: 10.1007/978-3-030-65943-1_15] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Naked mole-rats are highly valuable research models and popular exhibition animals at zoos worldwide. Here, we provide comprehensive descriptions of common postmortem findings of naked mole-rats from both research colonies and populations managed in zoological institutions. Included are brief reviews of their natural history and related physiologic adaptations, unique anatomical features, gross and histologic lesions of common as well as rarely reported disease processes, and discussions of possible pathogeneses with recommendations for future investigations to fill knowledge gaps. Based on postmortem data of several hundreds of naked mole-rats in managed care, it is clear that cancer is extremely rare and infectious disease is infrequently reported. However, despite relatively benign aging phenotypes in this species, several degenerative processes have been nevertheless observed in older populations of naked mole-rats. As such, some potential diet and husbandry-related issues are discussed in addition to the one of the most prominent causes of morbidity and mortality, conspecific aggression and traumas. From this review of lesions and disease, it is clear that pathology, including histopathology, is integral to better understanding mechanisms of healthy aging and cancer resistance of these extraordinary rodents.
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Affiliation(s)
- Martha A Delaney
- Zoological Pathology Program, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Denise M Imai
- Comparative Pathology Laboratory, School of Veterinary Medicine, University of California at Davis, Davis, CA, USA
| | - Rochelle Buffenstein
- Calico Life Sciences LLC, South San Francisco, CA, USA. .,Department of Pharmacology, University of Texas Health at San Antonio, San Antonio, TX, USA.
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Kumar Chaudhary M, Rizvi SI. Invertebrate and vertebrate models in aging research. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2019; 163:114-121. [PMID: 30837761 DOI: 10.5507/bp.2019.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 02/06/2019] [Indexed: 12/27/2022] Open
Abstract
Therapeutic interventions that can delay age associated diseases and ensure a longer health-span is a major goal of aging research. Consequent to understanding that aging is a modifiable trait, a large number of studies are currently being undertaken to elucidate the mechanism(s) of the aging process. Research on human aging and longevity is difficult, due to longer time frame, ethical concerns and environmental variables. Most of the present day understanding about the aging process comes through studies conducted on model organisms. These provide suitable platforms for understanding underlying mechanism(s) which control aging and have led to major discoveries that emphasize the evolutionarily conserved molecular pathways as key players that respond to extra and intracellular signals. This is a review of various invertebrate and vertebrate models including yeast, Drosophila, C. elegans, rodents, naked mole rat, and birds, currently used in aging research with emphasis on how well they can mimic aging in higher animals and humans.
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Affiliation(s)
| | - Syed Ibrahim Rizvi
- Department of Biochemistry, University of Allahabad, Allahabad-211002, India
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8
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Species comparison of liver proteomes reveals links to naked mole-rat longevity and human aging. BMC Biol 2018; 16:82. [PMID: 30068331 PMCID: PMC6090990 DOI: 10.1186/s12915-018-0547-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/28/2018] [Indexed: 12/04/2022] Open
Abstract
Background Mammals display a wide range of variation in their lifespan. Investigating the molecular networks that distinguish long- from short-lived species has proven useful to identify determinants of longevity. Here, we compared the livers of young and old long-lived naked mole-rats (NMRs) and the phylogenetically closely related, shorter-lived, guinea pigs using an integrated omics approach. Results We found that NMR livers display a unique expression pattern of mitochondrial proteins that results in distinct metabolic features of their mitochondria. For instance, we observed a generally reduced respiration rate associated with lower protein levels of respiratory chain components, particularly complex I, and increased capacity to utilize fatty acids. Interestingly, we show that the same molecular networks are affected during aging in both NMRs and humans, supporting a direct link to the extraordinary longevity of both species. Finally, we identified a novel detoxification pathway linked to longevity and validated it experimentally in the nematode Caenorhabditis elegans. Conclusions Our work demonstrates the benefits of integrating proteomic and transcriptomic data to perform cross-species comparisons of longevity-associated networks. Using a multispecies approach, we show at the molecular level that livers of NMRs display progressive age-dependent changes that recapitulate typical signatures of aging despite the negligible senescence and extraordinary longevity of these rodents. Electronic supplementary material The online version of this article (10.1186/s12915-018-0547-y) contains supplementary material, which is available to authorized users.
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Lewis KN, Rubinstein ND, Buffenstein R. A window into extreme longevity; the circulating metabolomic signature of the naked mole-rat, a mammal that shows negligible senescence. GeroScience 2018; 40:105-121. [PMID: 29679203 PMCID: PMC5964061 DOI: 10.1007/s11357-018-0014-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 03/15/2018] [Indexed: 12/23/2022] Open
Abstract
Mouse-sized naked mole-rats (Heterocephalus glaber), unlike other mammals, do not conform to Gompertzian laws of age-related mortality; adults show no age-related change in mortality risk. Moreover, we observe negligible hallmarks of aging with well-maintained physiological and molecular functions, commonly altered with age in other species. We questioned whether naked mole-rats, living an order of magnitude longer than laboratory mice, exhibit different plasma metabolite profiles, which could then highlight novel mechanisms or targets involved in disease and longevity. Using a comprehensive, unbiased metabolomics screen, we observe striking inter-species differences in amino acid, peptide, and lipid metabolites. Low circulating levels of specific amino acids, particularly those linked to the methionine pathway, resemble those observed during the fasting period at late torpor in hibernating ground squirrels and those seen in longer-lived methionine-restricted rats. These data also concur with metabolome reports on long-lived mutant mice, including the Ames dwarf mice and calorically restricted mice, as well as fruit flies, and even show similarities to circulating metabolite differences observed in young human adults when compared to older humans. During evolution, some of these beneficial nutrient/stress response pathways may have been positively selected in the naked mole-rat. These observations suggest that interventions that modify the aging metabolomic profile to a more youthful one may enable people to lead healthier and longer lives.
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Affiliation(s)
- Kaitlyn N Lewis
- Calico Life Sciences LLC, 1170 Veterans Blvd., South San Francisco, 94080, USA
| | - Nimrod D Rubinstein
- Calico Life Sciences LLC, 1170 Veterans Blvd., South San Francisco, 94080, USA
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The system capacity view of aging and longevity. QUANTITATIVE BIOLOGY 2017. [DOI: 10.1007/s40484-017-0115-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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11
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Lagunas-Rangel FA, Chávez-Valencia V. Learning of nature: The curious case of the naked mole rat. Mech Ageing Dev 2017; 164:76-81. [DOI: 10.1016/j.mad.2017.04.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 03/24/2017] [Accepted: 04/28/2017] [Indexed: 02/06/2023]
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Haron A, Dahan Y, Shinder D, Druyan S. Physiological effects of hypoxic conditions during the plateau period on the chicken embryo. Comp Biochem Physiol A Mol Integr Physiol 2016; 203:32-39. [PMID: 27557989 DOI: 10.1016/j.cbpa.2016.08.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 07/27/2016] [Accepted: 08/16/2016] [Indexed: 11/26/2022]
Abstract
The chick embryo employs several adaptive responses to hypoxic challenges, affecting both metabolism and oxygen (O2) transport. The present study assessed the effects of hypoxic conditions (17% O2) during the plateau phase on embryonic metabolic rate, cardiovascular parameters, and development up to hatching. The study was divided into 2 experiments: (1) Control; 17% O2 for 6h/d on E16-E18 (6H), and 17% O2 for 12h/d on E16-E18 (12H), and (2) Control; 12H, and 17% O2 continuously for 72h on E16-E18, (72H). Hypoxic embryos exhibited a significant increase in heart rate and an upward trend starting on E17 in hematocrit and hemoglobin levels. We observed a decrease in metabolism in 12H and 72H embryos during the plateau period; their oxygen consumption as well as yolk consumption were lower compared to Control and they hatched with a significantly lower body temperature, indicating lower heat production. There was no evidence of adaptation or long-term effects of exposure to 17% O2 for 6h/d. Exposure to 72h of hypoxic conditions led to significant physiological changes and had a detrimental influence on embryonic development and growth. In contrast, exposure to 12h/d produced moderate hypoxic changes, which helped the embryo to cope with the stress without significant influences on its growth and development. The decrease in metabolism may represent a metabolic adaptation through a decrease in resting metabolic rate and lower heat production. Such alterations may affect post-hatch performance and energy allocation between maintenance and growth, especially under stress when there is increased oxygen demand.
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Affiliation(s)
- A Haron
- Institute of Animal Science, Agrdicultural Research Organization, Volcani Center, HaMaccabim Road, Rishon Le Tsiyon, P.O. Box 15159, 7528809, Israel; Department of Animal Science, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University, Rehovot 76100, Israel
| | - Y Dahan
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel
| | - D Shinder
- Institute of Animal Science, Agrdicultural Research Organization, Volcani Center, HaMaccabim Road, Rishon Le Tsiyon, P.O. Box 15159, 7528809, Israel
| | - S Druyan
- Institute of Animal Science, Agrdicultural Research Organization, Volcani Center, HaMaccabim Road, Rishon Le Tsiyon, P.O. Box 15159, 7528809, Israel.
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Debebe T, Holtze S, Morhart M, Hildebrandt TB, Rodewald S, Huse K, Platzer M, Wyohannes D, Yirga S, Lemma A, Thieme R, König B, Birkenmeier G. Analysis of cultivable microbiota and diet intake pattern of the long-lived naked mole-rat. Gut Pathog 2016; 8:25. [PMID: 27239229 PMCID: PMC4884373 DOI: 10.1186/s13099-016-0107-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 05/16/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND A variety of microbial communities exist throughout the human and animal body. Genetics, environmental factors and long-term dietary habit contribute to shaping the composition of the gut microbiota. For this reason the study of the gut microbiota of a mammal exhibiting an extraordinary life span is of great importance. The naked mole-rat (Heterocephalus glaber) is a eusocial mammal known for its longevity and cancer resistance. METHODS Here we analyzed its gut microbiota by cultivating the bacteria under aerobic and anaerobic conditions and identifying their species by mass spectrometry. RESULTS Altogether, 29 species of microbes were identified, predominantly belonging to Firmicutes, and Bacteroidetes. The most frequent species were Bacillus megaterium (45.2 %), followed by Bacteroides thetaiotaomicron (19.4 %), Bacteroides ovatus, Staphylococcus sciuri and Paenibacillus spp., each with a frequency of 16.1 %. CONCLUSION Overall, the gut of the naked mole-rat is colonized by diverse, but low numbers of cultivable microbes compared with humans and mice. The primary food plants of the rodents are rich in polyphenols and related compounds, possessing anti-microbial, anti-inflammatory, anti-oxidative as well as anti-cancer activity which may contribute to their exceptionally healthy life.
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Affiliation(s)
- Tewodros Debebe
- Medical Faculty, Institute of Biochemistry, University of Leipzig, Johannisallee 30, 04103 Leipzig, Germany ; Medical Faculty, Institute of Medical Microbiology, University of Leipzig, Leipzig, Germany ; College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Susanne Holtze
- Department of Reproduction Management, Leibniz-Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Michaela Morhart
- Department of Reproduction Management, Leibniz-Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Thomas Bernd Hildebrandt
- Department of Reproduction Management, Leibniz-Institute for Zoo and Wildlife Research, Berlin, Germany
| | | | - Klaus Huse
- Leibniz Institute on Aging-Fritz Lipmann Institute, Jena, Germany
| | - Matthias Platzer
- Leibniz Institute on Aging-Fritz Lipmann Institute, Jena, Germany
| | - Dereje Wyohannes
- College of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Salomon Yirga
- College of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Alemayehu Lemma
- College of Veterinary Medicine and Agriculture, Addis Ababa University, Addis Ababa, Ethiopia
| | - Rene Thieme
- Department of Visceral, Transplantation, Thoracic and Vascular Surgery, University Medical Center Leipzig, University of Leipzig, Leipzig, Germany
| | - Brigitte König
- Medical Faculty, Institute of Medical Microbiology, University of Leipzig, Leipzig, Germany
| | - Gerd Birkenmeier
- Medical Faculty, Institute of Biochemistry, University of Leipzig, Johannisallee 30, 04103 Leipzig, Germany
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McIsaac RS, Lewis KN, Gibney PA, Buffenstein R. From yeast to human: exploring the comparative biology of methionine restriction in extending eukaryotic life span. Ann N Y Acad Sci 2016; 1363:155-70. [DOI: 10.1111/nyas.13032] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/25/2016] [Accepted: 01/27/2016] [Indexed: 12/19/2022]
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Buffenstein R, Nelson OL, Corbit KC. Questioning the preclinical paradigm: natural, extreme biology as an alternative discovery platform. Aging (Albany NY) 2015; 6:913-20. [PMID: 25553771 PMCID: PMC4276785 DOI: 10.18632/aging.100704] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The pace at which science continues to advance is astonishing. From cosmology, microprocessors, structural engineering, and DNA sequencing our lives are continually affected by science-based technology. However, progress in treating human ailments, especially age-related conditions such as cancer and Alzheimer's disease, moves at a relative snail's pace. Given that the amount of investment is not disproportionately low, one has to question why our hopes for the development of efficacious drugs for such grievous illnesses have been frustratingly unrealized. Here we discuss one aspect of drug development –rodent models – and propose an alternative approach to discovery research rooted in evolutionary experimentation. Our goal is to accelerate the conversation around how we can move towards more translative preclinical work.
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Affiliation(s)
- Rochelle Buffenstein
- Barshop Institute for Aging and Longevity Studies, University of Texas Health Science Center at San Antonio, TX University of Texas Health Science Center at San Antonio, TX USA
| | - O Lynne Nelson
- Department of Veterinary Clinical Sciences, Washington State University, Pullman, WA 9916, USA
| | - Kevin C Corbit
- Department of Metabolic Disorders, Amgen, Inc., Thousand Oaks, CA 91360, USA
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16
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Protracted brain development in a rodent model of extreme longevity. Sci Rep 2015; 5:11592. [PMID: 26118676 PMCID: PMC4484490 DOI: 10.1038/srep11592] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 05/27/2015] [Indexed: 12/11/2022] Open
Abstract
Extreme longevity requires the continuous and large-scale adaptation of organ systems to delay senescence. Naked mole rats are the longest-living rodents, whose nervous system likely undergoes life-long adaptive reorganization. Nevertheless, neither the cellular organization of their cerebral cortex nor indices of structural neuronal plasticity along extreme time-scales have been established. We find that adult neurogenesis and neuronal migration are not unusual in naked mole rat brains. Instead, we show the prolonged expression of structural plasticity markers, many recognized as being developmentally controlled, and multi-year-long postnatal neuromorphogenesis and spatial synapse refinement in hippocampal and olfactory structures of the naked mole rat brain. Neurophysiological studies on identified hippocampal neurons demonstrated that morphological differentiation is disconnected from the control of excitability in all neuronal contingents regardless of their ability to self-renew. Overall, we conclude that naked mole rats show an extremely protracted period of brain maturation that may permit plasticity and resilience to neurodegenerative processes over their decades-long life span. This conclusion is consistent with the hypothesis that naked mole rats are neotenous, with retention of juvenile characteristics to permit survival in a hypoxic environment, with extreme longevity a consequence of greatly retarded development.
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Triplett JC, Swomley A, Kirk J, Lewis K, Orr M, Rodriguez K, Cai J, Klein JB, Buffenstein R, Butterfield DA. Metabolic clues to salubrious longevity in the brain of the longest-lived rodent: the naked mole-rat. J Neurochem 2015; 134:538-50. [PMID: 25940666 DOI: 10.1111/jnc.13149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 04/13/2015] [Accepted: 04/23/2015] [Indexed: 12/16/2022]
Abstract
Naked mole-rats (NMRs) are the oldest-living rodent species. Living underground in a thermally stable ecological niche, NMRs have evolved certain exceptional traits, resulting in sustained health spans, negligible cognitive decline, and a pronounced resistance to age-related disease. Uncovering insights into mechanisms underlying these extraordinary traits involved in successful aging may conceivably provide crucial clues to extend the human life span and health span. One of the most fundamental processes inside the cell is the production of ATP, which is an essential fuel in driving all other energy-requiring cellular activities. Not surprisingly, a prominent hallmark in age-related diseases, such as neurodegeneration and cancer, is the impairment and dysregulation of metabolic pathways. Using a two-dimensional polyacrylamide gel electrophoresis proteomics approach, alterations in expression and phosphorylation levels of metabolic proteins in the brains of NMRs, aged 2-24 years, were evaluated in an age-dependent manner. We identified 13 proteins with altered levels and/or phosphorylation states that play key roles in various metabolic pathways including glycolysis, β-oxidation, the malate-aspartate shuttle, the Tricarboxylic Acid Cycle (TCA) cycle, the electron transport chain, NADPH production, as well as the production of glutamate. New insights into potential pathways involved in metabolic aspects of successful aging have been obtained by the identification of key proteins through which the NMR brain responds and adapts to the aging process and how the NMR brain adapted to resist age-related degeneration. This study examines the changes in the proteome and phosphoproteome in the brain of the naked mole-rat aged 2-24 years. We identified 13 proteins (labeled in red) with altered expression and/or phosphorylation levels that are conceivably associated with sustained metabolic functions in the oldest NMRs that may promote a sustained health span and life span.
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Affiliation(s)
- Judy C Triplett
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Aaron Swomley
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Jessime Kirk
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Katilyn Lewis
- Sam and Ann Barsop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Miranda Orr
- Sam and Ann Barsop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Karl Rodriguez
- Sam and Ann Barsop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Jian Cai
- Department of Nephrology and Proteomics Center, University of Louisville, Louisville, Kentucky, USA
| | - Jon B Klein
- Department of Nephrology and Proteomics Center, University of Louisville, Louisville, Kentucky, USA
| | - Rochelle Buffenstein
- Sam and Ann Barsop Institute for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas, USA.,Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - D Allan Butterfield
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA.,Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
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Delaney MA, Nagy L, Kinsel MJ, Treuting PM. Spontaneous histologic lesions of the adult naked mole rat (Heterocephalus glaber): a retrospective survey of lesions in a zoo population. Vet Pathol 2013; 50:607-21. [PMID: 23355517 DOI: 10.1177/0300985812471543] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Naked mole rats (NMRs; Heterocephalus glaber) are highly adapted, subterranean, eusocial rodents from semiarid regions of the eastern horn of Africa and the longest-living rodent known with a maximum life span of up to 30 years. They are a unique model for aging research due to their physiology, extreme longevity, and, when compared to mice and rats, resistance to cancer. Published surveys of disease in NMRs are sparse. Captive colonies in zoological collections provide an opportunity to monitor spontaneous disease over time in a seminatural environment. This retrospective study describes common lesions of a zoo population over a 15-year period during which 138 adult NMRs were submitted for gross and histologic evaluation. Of these, 61 (44.2%) were male, 77 (55.8%) female, 45 (32.6%) died, and 93 (67.4%) were euthanized. The most frequent cause of death or reason for euthanasia was conspecific trauma (bite wounds) and secondary complications. Some common histologic lesions and their prevalence were renal tubular mineralization (82.6%), hepatic hemosiderosis (64.5%), bite wounds (63.8%), chronic progressive nephropathy (52.9%), and calcinosis cutis (10.1%). In sum, 104 (75.4%) NMRs had more than one of the most prevalent histologic lesions. No malignant neoplasms were noted; however, there was a case of renal tubular adenomatous hyperplasia with nuclear atypia and compression that in rats is considered a preneoplastic lesion. This retrospective study confirms the NMR's relative resistance to cancer in spite of development of other degenerative diseases and highlights the utility of zoological databases for baseline pathological data on nontraditional animal models.
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Affiliation(s)
- M A Delaney
- University of Illinois Zoological Pathology Program, Loyola University Medical Center Building 101, 2160 South First Avenue, Maywood, IL 60153, USA.
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Petrželková KJ, Schovancová K, Profousová I, Kišidayová S, Váradyová Z, Pekár S, Kamler J, Modrý D. The effect of low- and high-fiber diets on the population of entodiniomorphid ciliates Troglodytella abrassarti in captive chimpanzees (Pan troglodytes). Am J Primatol 2012; 74:669-75. [PMID: 22553174 DOI: 10.1002/ajp.22021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 02/01/2012] [Accepted: 02/01/2012] [Indexed: 11/06/2022]
Abstract
Troglodytella abrassarti is an intestinal entodiniomorphid ciliate commonly diagnosed in the feces of wild and captive chimpanzees (Pan troglodytes). Entodiniomorphids could be considered to have a mutualistic relationship with the great apes, in that the ciliates benefit from the intestinal ecosystem of the host, while also contributing to the fiber fermentation process. We examined the effect of diet on the infection intensities of T. abrassarti in two captive chimpanzees in the Liberec Zoo, Czech Republic. The chimpanzees were fed a low-fiber diet (LFD) with 14% neutral detergent fiber (NDF) and a high-fiber diet (HFD; 26% NDF) for 10 days with one transition, and two 10-day adaptation periods. Fecal samples were examined coproscopically with the merthiolate-iodine-formaldehyde concentration (MIFC) technique, in order to quantify the number of ciliates per gram of feces. A significant trend of increasing T. abrassarti numbers was observed when the animals were fed the LFD, compared to when they were fed the HFD. Our results suggest, however, that infection intensities of T. abrassarti in captive chimpanzees are not influenced primarily by the amount of fiber in the diet, but rather by the dietary starch concentration (HFD: 1%; LFD: 8%).
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Affiliation(s)
- Klára J Petrželková
- Institute of Vertebrate Biology, Academy of Sciences of the Czech Republic, Brno, Czech Republic.
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Abstract
Naked mole rats are mouse-sized rodents that have become an important animal model in biomedical research. They play a unique mammalian role in behavioral and ecophysiological research of life underground. This chapter studies the general physiology, anatomy of organ systems, husbandry, and uses in research of the naked mole rats. Naked mole rats belong to the order Rodentia in that they have two incisor teeth on the upper and lower arcade that continuously grow. The skin is loose, wrinkled, and brownish pink in color. The body is for the most part absent of hairs with the exception of tactile hairs that are regularly arranged throughout the body and which are particularly prominent around the face and to a lesser extent on the tail. They are typically housed at 28–30°C, and at 50–60% relative humidity. Because naked mole rats are social and have cooperative behaviors, the study of their conduct has more applicability to people. The chapter describes the models of experimental research on the naked mole rat such as the model of reproductive suppression, model of somatosensory processing, model of bone elongation, and model of aging.
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Lewis KN, Mele J, Hornsby PJ, Buffenstein R. Stress resistance in the naked mole-rat: the bare essentials - a mini-review. Gerontology 2012; 58:453-62. [PMID: 22572398 PMCID: PMC4439786 DOI: 10.1159/000335966] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 12/21/2011] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Studies comparing similar-sized species with disparate longevity may elucidate novel mechanisms that abrogate aging and prolong good health. We focus on the longest living rodent, the naked mole-rat. This mouse-sized mammal lives ~8 times longer than do mice and, despite high levels of oxidative damage evident at a young age, it is not only very resistant to spontaneous neoplasia but also shows minimal decline in age-associated physiological traits. OBJECTIVES We assess the current status of stress resistance and longevity, focusing in particular on the molecular and cellular responses to cytotoxins and other stressors between the short-lived laboratory mouse and the naked mole-rat. RESULTS Like other experimental animal models of lifespan extension, naked mole-rat fibroblasts are extremely tolerant of a broad spectrum of cytotoxins including heat, heavy metals, DNA-damaging agents and xenobiotics, showing LD(50) values between 2- and 20-fold greater than those of fibroblasts of shorter-lived mice. Our new data reveal that naked mole-rat fibroblasts stop proliferating even at low doses of toxin whereas those mouse fibroblasts that survive treatment rapidly re-enter the cell cycle and may proliferate with DNA damage. Naked mole-rat fibroblasts also show significantly higher constitutive levels of both p53 and Nrf2 protein levels and activity, and this increases even further in response to toxins. CONCLUSION Enhanced cell signaling via p53 and Nrf2 protects cells against proliferating with damage, augments clearance of damaged proteins and organelles and facilitates the maintenance of both genomic and protein integrity. These pathways collectively regulate a myriad of mechanisms which may contribute to the attenuated aging profile and sustained healthspan of the naked mole-rat. Understanding how these are regulated may be also integral to sustaining positive human healthspan well into old age and may elucidate novel therapeutics for delaying the onset and progression of physiological declines that characterize the aging process.
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Affiliation(s)
- Kaitlyn N. Lewis
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Tex., USA
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Tex., USA
| | - James Mele
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Tex., USA
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Tex., USA
| | - Peter J. Hornsby
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Tex., USA
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Tex., USA
| | - Rochelle Buffenstein
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Tex., USA
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Tex., USA
- *Rochelle Buffenstein, Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, 15355 Lambda Drive, STCBM No. 2.2, San Antonio, TX 78209 (USA), Tel. +1 210 562 5062, E-Mail
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Survival and morphologic changes of entodiniomorphid ciliate Troglodytella abrassarti in chimpanzee feces. J Zoo Wildl Med 2011; 42:69-74. [PMID: 22946373 DOI: 10.1638/2010-0100.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Entodiniomorphid ciliates occur in the hindgut of both captive and wild African great apes. These ciliates do not form cysts, and therefore they are more susceptible for degradation. This present study focused on the survival, quantification, and decomposition processes of Troglodytella abrassarti trophozoites in the feces of captive chimpanzees. Fecal samples were examined using wet mounts and the merthiolate-iodine-formaldehyde concentration method, and the number of ciliates was expressed as ciliates per gram, which did not differ when examined from three different samples of the same feces. Trophozoites of T. abrassarti survived 5-15 hr after defecation at 25 degrees C under aerobic conditions. Decomposition of trophozoites began immediately after defecation; however, most of the trophozoites had a compact shape and visible cilia. Trophozoites, although without cilia, can be detected in the feces 55-65 hr after defecation, although most of the trophozoites were fragmented. The total number of ciliates in the sample started to decrease 35-55 hr after defecation. The absence of entodiniomorphid ciliates in fecal samples could not be caused by delayed feces fixation; instead, the absence was due to low sensitivity of coproscopic techniques. However, because of quick morphologic changes of trophozoites, accurate identification of ciliates in older samples may be difficult or even impossible.
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Pomajbíková K, Petrzelková KJ, Profousová I, Petrásová J, Kisidayová S, Varádyová Z, Modrý D. A survey of entodiniomorphid ciliates in chimpanzees and bonobos. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2010; 142:42-8. [PMID: 19845028 DOI: 10.1002/ajpa.21191] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Intestinal entodiniomorphid ciliates are commonly diagnosed in the feces of wild apes of the genera Pan and Gorilla. Although some authors previously considered entodiniomorphid ciliates as possible pathogens, a symbiotic function within the intestinal ecosystem and their participation in fiber fermentation has been proposed. Previous studies have suggested that these ciliates gradually disappear under captive conditions. We studied entodiniomorphid ciliates in 23 captive groups of chimpanzees, three groups of captive bonobos and six populations of wild chimpanzees. Fecal samples were examined using Sheather's flotation and Merthiolate-Iodine-Formaldehyde Concentration (MIFC) methods. We quantified the number of ciliates per gram of feces. The MIFC method was more sensitive for ciliate detection than the flotation method. Ciliates of genus Troglodytella were detected in 13 groups of captive chimpanzees, two groups of bonobos and in all wild chimpanzee populations studied. The absence of entodiniomorphids in some captive groups might be because of the extensive administration of chemotherapeutics in the past or a side-effect of the causative or prophylactic administration of antiparasitic or antibiotic drugs. The infection intensities of ciliates in captive chimpanzees were higher than in wild ones. We suppose that the over-supply of starch, typical in captive primate diets, might induce an increase in the number of ciliates. In vitro studies on metabolism and biochemical activities of entodiniomorphids are needed to clarify their role in ape digestion.
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Affiliation(s)
- Katerina Pomajbíková
- Department of Parasitology, University of Veterinary and Pharmaceutical Sciences, 612 4 Brno, Czech Republic.
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Mele J, Edrey YH, Lewis KN, Buffenstein R. Mechanisms of aging in the naked mole-rat: The case for programmed aging. RUSS J GEN CHEM+ 2010. [DOI: 10.1134/s1070363210070418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kotzé SH, Van Der Merwe EL, Bennett NC, O'Riain MJ. The comparative anatomy of the abdominal gastrointestinal tract of six species of African mole-rats (Rodentia, Bathyergidae). J Morphol 2010; 271:50-60. [PMID: 19623625 DOI: 10.1002/jmor.10778] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The gastrointestinal tracts (GITs) of six species of African mole-rats (Bathyergidae) were compared. The aim was to provide a comprehensive anatomical comparison between the different species. The relative shape, length, and surface areas were taken into account to determine whether the GITs are phylogenetically constrained or exhibit anatomical adaptations in response to diets. In all six species the stomach was simple and glandular. With the exception of Heterocephalus glaber, the caecum was coiled in a flat spiral, the ascending colon was arranged in a loop of varying lengths, and a mucosal colonic papillary-lined groove was present in the ascending colon in all species. By contrast, the caecum in H. glaber was uncoiled, the ascending colon was not looped, and the groove was not papillated. A caeco-appendix was observed only in Bathyergus suillus and Georychus capensis. Hierarchical multivariate cluster analysis on the presence/absence of nine anatomical structures associated with the GIT of mole-rats revealed that H. glaber was anatomically the least similar of the six species (77.6% similarity) with respect to the nine GIT variables included. All Cryptomys species were the same (100% similarity), and two species B. suillus and G. capensis grouped together and were more similar to the Cryptomys genus (95% similarity) than they were to H. glaber. These findings support previous phylogenetic classifications. The voluminous caeco-colon in B. suillus may be explained by its ingestion of grasses in addition to below-ground storage organs of plants. We conclude that phylogeny and diet affect the GIT anatomy of the African mole rats studied here.
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Affiliation(s)
- Sanet H Kotzé
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Stellenbosch, Tygerberg 7505, South Africa.
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Sassi PL, Borghi CE, Bozinovic F. Spatial and Seasonal Plasticity in Digestive Morphology of Cavies (Microcavia australis) Inhabiting Habitats with Different Plant Qualities. J Mammal 2007. [DOI: 10.1644/06-mamm-a-046r1.1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Johnson SA, Jackson S, Abratt VR, Wolfaardt GM, Cordero-Otero R, Nicolson SW. Xylose utilization and short-chain fatty acid production by selected components of the intestinal microflora of a rodent pollinator (Aethomys namaquensis). J Comp Physiol B 2006; 176:631-41. [PMID: 16676189 DOI: 10.1007/s00360-006-0086-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2005] [Revised: 03/27/2006] [Accepted: 03/31/2006] [Indexed: 11/28/2022]
Abstract
Namaqua rock mice (Aethomys namaquensis) consume nectar xylose when visiting Protea flowers. Whole-animal metabolism studies suggest that the gastrointestinal microflora plays an important role in xylose metabolism in A. namaquensis. We collected caecal contents under anaerobic conditions, cultured caecal microflora both aerobically and anaerobically, and assessed caecal microbial xylose utilization using a (14)C-xylose incubation assay. All four mice sampled hosted culturable caecal micro-organisms that tested positive for xylose utilization. These were classified by 16S rRNA based taxonomy as: Bacillus subtilis, Bacillus pumilus, Bacillus licheniformis, Shigella boydii, Arthrobacter sp. and members of the fungal genera Aspergillus and Penicillium. Cultures of these isolates were then analyzed by gas chromatography to determine the types and quantities of short-chain fatty acids produced by xylose fermentation. These results are discussed in the context of other studies of gut microflora in vertebrates.
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Affiliation(s)
- S A Johnson
- Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
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Kramer B, Buffenstein R. The pancreas of the naked mole-rat (Heterocephalus glaber): an ultrastructural and immunocytochemical study of the endocrine component of thermoneutral and cold acclimated animals. Gen Comp Endocrinol 2004; 139:206-14. [PMID: 15560867 DOI: 10.1016/j.ygcen.2004.09.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2004] [Revised: 08/13/2004] [Accepted: 09/03/2004] [Indexed: 11/21/2022]
Abstract
Endocrine cell distribution within the islets of Langerhans may vary both between species and under different energetically demanding conditions such as cold acclimation. The naked mole-rat, Heterocephalus glaber, lacking an effective insulatory pelage, is effectively a poikilotherm, yet it shows a typical mammalian cold-acclimation response by substantially increasing food intake to meet higher energy requirements when housed at lower temperatures. The endocrine component of the pancreas of thermoneutral and cold-acclimated naked mole-rats was thus characterized using immunocytochemistry and ultrastructural analyses. Four distinct endocrine cells were identified: alpha (glucagon-producing), beta (insulin-producing), delta (somatostatin-producing), and PP (pancreatic polypeptide-producing) cells. Distribution of these cells differed from that of other rodents, in that beta cells formed the mantle while alpha cells formed the core of the islets. This distribution may contribute to the observed insulin insensitivity of this species, as indicated in abnormal responses to glucose tolerance tests. Insulin-producing cells, however, were more numerous than glucagon-producing cells. This ratio was unchanged with cold acclimation. Immunoreactivity of alpha and beta cells was more intense in cold-acclimated than in thermoneutral animals, possibly indicative of a change in hormonal production in animals housed at a lower temperature.
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Affiliation(s)
- Beverley Kramer
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg 2193, South Africa.
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Peterson J, Wunder BA. Food Sorting by Collared Lemmings (Dicrostonyx groenlandicus) and Prairie Voles (Microtus ochrogaster): A Cautionary Note for Digestibility Studies. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0300-9629(96)00161-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Buffenstein R, Yahav S. Fibre utilization by Kalahari dwelling subterranean Damara mole-rats (Cryptomys damarensis) when fed their natural diet of gemsbok cucumber tubers (Acanthosicyos naudinianus). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PHYSIOLOGY 1994; 109:431-6. [PMID: 7956122 DOI: 10.1016/0300-9629(94)90147-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Kalahari dwelling Damara mole-rats (Cryptomys damarensis) naturally feed on a high fibre diet of underground gemsbok cucumber tubers, Acanthosicyos naudinianus. We investigated the degree of fibre utilization and fermentation on this diet by measuring caecal characteristics (namely temperature, pH and weight) and in vitro rates of gas and short chain fatty acid (SCFA) production in these underground dwelling hind-gut fermentors. Rectal temperatures (33.8 +/- 0.6 degrees C) were consistently higher than caecal temperatures (33.3 +/- 0.6 degrees C). Furthermore, a 0.8 degrees C gradient of temperatures existed within the caecum, with the lowest temperature occurring in the corpus caeci. Both rates of gas production (4.74 +/- 0.6 ml/g dry matter/hr) and SCFA production (266.80 +/- 9.251 mumol/caecum per hr) were high, with proportionately more acetic acid produced than any other SCFA. Nevertheless, the initial concentrations of SCFAs present in the caecum were low (52 +/- 17 mM) implying a rapid rate of absorption of these SCFAs. The high rates of fermentation provide a considerable amount of energy that would otherwise be trapped in fibre and thus unavailable to the animal. This highly efficient caecal fermentation enables the Damara mole-rat to maximally exploit the underground food resources in the arid-zone ecotope.
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Affiliation(s)
- R Buffenstein
- Department of Physiology, Medical School, University of the Witwatersrand, Johannesburg, South Africa
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Pitcher T, Buffenstein R. Passive uptake in the small intestine and active uptake in the hindgut contribute to the highly efficient mineral metabolism of the common mole-rat, Cryptomys hottentotus. Br J Nutr 1994; 71:573-82. [PMID: 8011610 DOI: 10.1079/bjn19940164] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cryptomys hottentotus has no access to dietary or endogenous sources of cholecalciferol (D3). Serum concentrations of calcifediol (25(OH)D3) were undetectable (< 5 ng/ml) and calcitriol (1,25(OH)2D3), although detectable in plasma, was at a low concentration (31.40 (SEM 3.06 pg/ml). Despite their naturally impoverished vitamin D status, these animals exhibited highly efficient mineral absorption processes (Ca apparent fractional absorption efficiency, AFA (%) 95.33 (SEM 1.36); inorganic P (P(i)) AFA (%) 93.49 (SEM 0.81)). Furthermore, plasma mineral content was tightly regulated (Ca 2.57 (SEM 0.08) mmol/l; Mg 1.23 (SEM 0.05) mmol/l; P(i) 2.12 (SEM 0.15) mmol/l). Mode of uptake in C. hottentotus was unlike that in other D3-replete mammals. First, passive (rather than active) uptake occurred in the traditional site of active Ca absorption (with serosal:mucosal (S:M) ratios in the duodenum of 1.32 (SEM 0.13)), and the only site of active Ca uptake was the hindgut (caecum S:M 3.35 (SEM 0.46); proximal colon S:M 2.13 (SEM 0.30)). Despite the presence of active uptake in these hindgut regions, their overall contribution to the daily rate of mineral absorption was small (9.53 (SEM 1.27)%). These underground inhabitants rely upon highly efficient, passive mineral uptake. This is adequate to meet their mineral requirements and maintain mineral homeostasis in the absence of vitamin D.
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Affiliation(s)
- T Pitcher
- Physiology Department, Medical School, University of the Witwatersrand, Parktown, South Africa
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Yahav S, Buffenstein R. Cholecalciferol supplementation alters gut function and improves digestibility in an underground inhabitant, the naked mole rat (Heterocephalus glaber), when fed on a carrot diet. Br J Nutr 1993; 69:233-41. [PMID: 8384476 DOI: 10.1079/bjn19930025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Naked mole rats (Heterocephalus glaber) lead a strictly subterranean existence and appear to be naturally deficient in cholecalciferol (D3). Oral supplementation with D3 (Ds) led to a 1.8-fold increase in food intake and the associated enlargement (1.4-fold) of the caecum. The effect of Ds, and the concomitant increase in food intake, on caecal fermentation efficiency when animals were fed on a carrot-based diet was determined by measuring the rate of both gas production and short-chain fatty acid (SCFA) production. Microbial-controlled fermentation processes in the caecum were enhanced with Ds when compared with animals not receiving a D3 supplement (Dn). Both the rates of gas production (Dn 10.76 (SE 0.77), Ds 15.20 (SE 1.77) ml/g dry matter (DM) per h) and SCFA production (Dn 463.0 (SE 33.7), Ds 684.3 (SE 74.8) mumol/g DM per h) increased more than 1.4-fold per g DM caecal substrate. These factors contributed to the higher digestibility of the food in Ds animals. The larger quantity of energy available to D3-replete naked mole rats was not used in anabolic processes, for these animals maintained mass. These findings suggest that metabolic rate in D3-replete animals was elevated. Thus, despite improved gut function, D3-replete animals may be disadvantaged by their higher energy and food requirements in their natural milieu.
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Affiliation(s)
- S Yahav
- Department of Paediatrics, University of the Witwatersrand, Baragwanath Hospital, Johannesburg, South Africa
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Williams AG, Lloyd D. Biological Activities of Symbiotic and Parasitic Protozoa and Fungi in Low-Oxygen Environments. ADVANCES IN MICROBIAL ECOLOGY 1993. [DOI: 10.1007/978-1-4615-2858-6_5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Yahav S, Buffenstein R. Caecal function provides the energy of fermentation without liberating heat in the poikilothermic mammal, Heterocephalus glaber. J Comp Physiol B 1992; 162:216-8. [PMID: 1613158 DOI: 10.1007/bf00357526] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This paper presents the first report of a mammalian internal organ with a lower temperature than its abdominal surrounds. Heterocephalus glaber, the naked mole-rat, is a poikilothermic mammal that leads a strictly subterranean existence and consumes a high proportion of fibre in its diet. The fermentation chamber in these animals appears to absorb rather than generate heat and the temperature in it was consistently 1.2 +/- 0.5 degrees C (n = 17) lower than rectal temperature. A caecum with a lower temperature than its abdominal surrounds provides an internal heat sink which could be advantageous for metabolic heat dissipation in the plugged humid burrows in which the naked mole-rat permanently resides.
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Affiliation(s)
- S Yahav
- Department of Physiology, Medical School, University of Witwatersrand, Johannesburg, South Africa
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Yahav S, Buffenstein R. The effect of temperature on caecal fermentation processes in a poikilothermic mammal, Heterocephalus glaber. J Therm Biol 1991. [DOI: 10.1016/0306-4565(91)90061-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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