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De Gregorio MA. The IR Platypus. Cardiovasc Intervent Radiol 2024; 47:515-516. [PMID: 38129336 DOI: 10.1007/s00270-023-03587-8] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 10/05/2023] [Indexed: 12/23/2023]
Affiliation(s)
- M A De Gregorio
- University of Zaragoza, Domingo Miral S/N, 50009, Zaragoza, Spain.
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2
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Choi J, Choi Y, Kim SD. Body distribution and ecotoxicological effect of nanoplastics in freshwater fish, Zacco platypus. Chemosphere 2023; 341:140107. [PMID: 37683945 DOI: 10.1016/j.chemosphere.2023.140107] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 09/10/2023]
Abstract
The increased consumption of plastics worldwide, has led to the emergence of nanoplastics as important environmental pollutants. Despite the presence of nanoplastics in aquatic environments, their effects on ecosystems remain largely unexplored due to the analysis complexity. This study investigated the organ accumulation and toxic effects of 50 nm polystyrene nanoplastics (PS-NPs) in Zacco platypus (Z. platypus; also known as pale chub fish) using pyrolyzer-gas chromatography-mass spectrometry (Pyr-GC/MS). PS-NPs accumulated in Z. platypus' brain, digestive tract, branchia, and liver, causing changes at cellular level. Over a 14-day exposure, the accumulated PS-NPs led to observable changes in fish behavior (e.g., Total traveled distance and maximum velocity). In addition, the oxidative stress in each organ of Z. platypus increased as the exposure concentration of PS-NPs increased. This study shows that accumulation of nanoplastics in fish, resulting in behavioral changes and biochemical toxicity. As the pattern of change magnifies with exposure time and concentration, from a long-term perspective, the influence of nanoplastics on aquatic ecosystems become evident. This underscores the urgency for continuous research into the potential risks of nanoplastics in aquatic ecosystems.
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Affiliation(s)
- Jiwon Choi
- Department of Civil and Environmental Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Yeowool Choi
- Department of Economic and Environmental Research, The Incheon Institute, 98 Simgok-ro, Seo-gu, Incheon, 22711, South Korea.
| | - Sang Don Kim
- School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju, 61005, South Korea; Environmental Analysis Center, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju, 61005, South Korea.
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3
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Kirkendall LR, Atkinson TH. The rare genus Myo platypus (Coleoptera: Curculionidae: Platypodinae): three new species, new reports, and first records for South America. Zootaxa 2023; 5351:301-321. [PMID: 38221486 DOI: 10.11646/zootaxa.5351.3.1] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Indexed: 01/16/2024]
Abstract
We describe three new species of Myoplatypus Wood, 1993: from Peru, Myoplatypus petrovi Kirkendall new species; from Honduras, M. quadricornis Kirkendall new species; from Nicaragua (M. nicaraguensis Kirkendall new species). We transfer Platypus biprorus Blandford, 1896 and Platypus sicarius Wood, 1971 into Myoplatypus, and we synonymize Platypus querceus Wood, 1971 with M. biprorus. The net result of these actions is a genus comprising nine tropical and one temperate American species. Males of all species are illustrated by photographs and a key to all species is provided. The collections reported here include the first South American records of Myoplatypus, a genus hitherto known only from North and Central America. Most Myoplatypus species are known from just one or a few collections and none of the tropical species are very widespread; only five tropical species have any known hosts (Quercus [Fagaceae] for three of them). The paucity of specimens could be because of peculiarities of biology that lead to them being under-collected (such as restriction to high elevations), but it also could be that they are narrow endemics, in which case these pinhole borer species deserve conservation attention. Nosotros describimos tres nuevas especies de Myoplatypus Wood, 1993: de Per, Myoplatypus petrovi Kirkendall espcie nueva; de Honduras, M. quadricornis Kirkendall espcie nueva; de Nicaragua, M. nicaraguensis Kirkendall espcie nueva. Platypus biprorus Blandford, 1896 y Platypus sicarius Wood, 1971 se transfieren a Myoplatypus, y Platypus querceus Wood, 1971 se sinonimiza con M. biprorus Blandford. El resultado neto de estas acciones es un gnero que consiste en nueve espcies tropicales y una templada. Los machos de todas las especies estn ilustrados con fotografas y se da una clave para todas las especies. Las colecciones reportadas aqu incluyen los primeros registros sudamericanos de Myoplatypus, un gnero hasta ahora conocido solo en Amrica del Norte y Amrica Central. La mayora de las especies de Myoplatypus se conocen a partir de solo una o unas pocas colecciones y ninguna de las especies tropicales est muy extendida; slo cinco especies tropicales tienen hospedadores conocidos (tres de ellos son robles). La escasez de especmenes podra deberse a algunas peculiaridades de la biologa que los llevan a una recoleccin insuficiente (como la restriccin a grandes alturas), pero tambin podra ser que sean endmicos estrechos, en cuyo caso estas especies de barrenadores merecen atencin de conservacin.
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Affiliation(s)
- Lawrence R Kirkendall
- Department of Biological Sciences; University of Bergen; Postbox 7803; N-5020 Bergen; Norway.
| | - Thomas H Atkinson
- University of Texas Insect Collection; 3001 Lake Austin Blvd.; Suite 1.314; Austin; Texas 78702; U.S.A..
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4
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Cotet TS, Agrafiotis A, Kreiner V, Kuhn R, Shlesinger D, Manero-Carranza M, Khodaverdi K, Kladis E, Desideri Perea A, Maassen-Veeters D, Glänzer W, Massery S, Guerci L, Hong KL, Han J, Stiklioraitis K, D’Arcy VM, Dizerens R, Kilchenmann S, Stalder L, Nissen L, Vogelsanger B, Anzböck S, Laslo D, Bakker S, Kondorosy M, Venerito M, Sanz García A, Feller I, Oxenius A, Reddy ST, Yermanos A. e Platypus: an ecosystem for computational analysis of immunogenomics data. Bioinformatics 2023; 39:btad553. [PMID: 37682115 PMCID: PMC10518073 DOI: 10.1093/bioinformatics/btad553] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 08/08/2023] [Accepted: 09/06/2023] [Indexed: 09/09/2023] Open
Abstract
MOTIVATION The maturation of systems immunology methodologies requires novel and transparent computational frameworks capable of integrating diverse data modalities in a reproducible manner. RESULTS Here, we present the ePlatypus computational immunology ecosystem for immunogenomics data analysis, with a focus on adaptive immune repertoires and single-cell sequencing. ePlatypus is an open-source web-based platform and provides programming tutorials and an integrative database that helps elucidate signatures of B and T cell clonal selection. Furthermore, the ecosystem links novel and established bioinformatics pipelines relevant for single-cell immune repertoires and other aspects of computational immunology such as predicting ligand-receptor interactions, structural modeling, simulations, machine learning, graph theory, pseudotime, spatial transcriptomics, and phylogenetics. The ePlatypus ecosystem helps extract deeper insight in computational immunology and immunogenomics and promote open science. AVAILABILITY AND IMPLEMENTATION Platypus code used in this manuscript can be found at github.com/alexyermanos/Platypus.
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Affiliation(s)
- Tudor-Stefan Cotet
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Andreas Agrafiotis
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
- Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, Zurich 8093, Switzerland
| | - Victor Kreiner
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Raphael Kuhn
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Danielle Shlesinger
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Marcos Manero-Carranza
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Keywan Khodaverdi
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Evgenios Kladis
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Aurora Desideri Perea
- Center for Translational Immunology, University Medical Center Utrecht, Lundlaan 6, Utrecht 3584 EA, The Netherlands
| | - Dylan Maassen-Veeters
- Center for Translational Immunology, University Medical Center Utrecht, Lundlaan 6, Utrecht 3584 EA, The Netherlands
| | - Wiona Glänzer
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Solène Massery
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Lorenzo Guerci
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Kai-Lin Hong
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Jiami Han
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Kostas Stiklioraitis
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | | | - Raphael Dizerens
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Samuel Kilchenmann
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Lucas Stalder
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Leon Nissen
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Basil Vogelsanger
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Stine Anzböck
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Daria Laslo
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Sophie Bakker
- Center for Translational Immunology, University Medical Center Utrecht, Lundlaan 6, Utrecht 3584 EA, The Netherlands
| | - Melinda Kondorosy
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Marco Venerito
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Alejandro Sanz García
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Isabelle Feller
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Annette Oxenius
- Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, Zurich 8093, Switzerland
| | - Sai T Reddy
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
| | - Alexander Yermanos
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland
- Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, Zurich 8093, Switzerland
- Center for Translational Immunology, University Medical Center Utrecht, Lundlaan 6, Utrecht 3584 EA, The Netherlands
- Department of Pathology and Immunology, University of Geneva, 24 rue du Général-Dufour, Geneva 1211, Switzerland
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Lai S, Wang J, Wang Y, Li Y, Lin W, Meng L, Hao D. First record of two ambrosia beetle, Platypus quercivorus (Murayama) and Platypus koryoensis (Murayama) (Coleoptera: Curculionidae, Platypodinae) in Mainland China. Zootaxa 2023; 5284:397-400. [PMID: 37518729 DOI: 10.11646/zootaxa.5284.2.11] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Indexed: 08/01/2023]
Affiliation(s)
- Shengchang Lai
- Forestry College; Nanjing Forestry University; College of Agriculture; Jiangxi Agriculture University.
| | - Jianguo Wang
- College of Agriculture; Jiangxi Agriculture University.
| | - Ying Wang
- Animal & Plant Inspection and Quarantine Technology Center of Shenzhen Customs District.
| | - You Li
- College of Plant Protection; Fujian Agriculture and Forestry University.
| | - Wei Lin
- Technical Center of Gongbei Customs District.
| | - Lingzeng Meng
- College of Biological and Agricultural Sciences; Honghe University.
| | - Dejun Hao
- Forestry College; Nanjing Forestry University.
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Suman TY, Kim SY, Yeom DH, Jang Y, Jeong TY, Jeon J. Transcriptome and computational approaches highlighting the molecular regulation of Zacco platypus induced by mesocosm exposure to common disinfectant chlorine. Chemosphere 2023; 319:137989. [PMID: 36736481 DOI: 10.1016/j.chemosphere.2023.137989] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 01/26/2023] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Chlorine (Cl2) is a disinfectant often used in swimming pools and water treatment facilities. However, it is released into aquatic ecosystems, where it may harm non-targeted organisms. Here, we performed a mesocosm experiment exposing Zacco platypus (Z. platypus) to biocide Cl2 for 30 days (30 d) at two days' time points 15 days (15 d) and 30 d samples were collected. Here, Z. platypus was exposed to a sublethal concentration (0.1 mg/L) of Cl2, and comparative transcriptomics analyses were performed to determine their response mechanisms at the molecular level. According to RNA sequencing of the whole-body transcriptome, 860 and 1189 differentially expressed genes (DEGs) were identified from the 15 d and 30 d responses to Cl2, respectively. After enrichment analysis of GO (Gene Ontology) functions and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, identified DEGs were demonstrated to be associated with a variety of functions, including "ion binding and transmembrane transporters". Cl2 also induced oxidative stress in Z. platypus by increasing the levels of reactive oxygen species (ROS) while decreasing the catalase (CAT) content and the levels of solute carrier family 22 member 11 (slc22a11), Caspase-8 (casp-8), inducible nitric oxide synthase (NOS2), cytosolic phospholipase A2 gamma (PLA2G4). However, Z. platypus still allows recovery during stress suspension by increasing the expression levels of solute carrier family proteins. The GO and KEGG annotation results revealed that the expression of DEGs were related to the detoxification process, immune response, and antioxidant mechanism. Additionally, protein-protein interaction networks (PPI) and cytoHubba analyses identified sixteen hub genes and their interaction. These findings elucidate the regulation of various DEGs and signaling pathways in response to Cl2 exposure, which will improve our knowledge and laid foundation for further investigation of the toxicity of Cl2 to Z. platypus.
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Affiliation(s)
- Thodhal Yoganandham Suman
- Department of Environmental Engineering, Changwon National University, Changwon, Gyeongsangnamdo, 51140, Republic of Korea; School of Smart and Green Engineering, Changwon National University, Changwon, Gyeongsangnamdo, 51140, Republic of Korea
| | - Soo-Yeon Kim
- Gyeongnam Branch Institute, Korea Institute of Toxicology (KIT), Jinju-si, 52834, Republic of Korea
| | - Dong-Hyuk Yeom
- Gyeongnam Branch Institute, Korea Institute of Toxicology (KIT), Jinju-si, 52834, Republic of Korea
| | - Younghoon Jang
- Department of Biology and Chemistry, Changwon National University, Changwon, Republic of Korea
| | - Tae-Yong Jeong
- Department of Environmental Science, Hankuk University of Foreign Studies, 81, Oedae-ro, Mohyeon-eup,Cheoin-gu, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Junho Jeon
- Department of Environmental Engineering, Changwon National University, Changwon, Gyeongsangnamdo, 51140, Republic of Korea; School of Smart and Green Engineering, Changwon National University, Changwon, Gyeongsangnamdo, 51140, Republic of Korea.
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7
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Motoshima T, Nagashima A, Ota C, Oka H, Hosono K, Braasch I, Nishihara H, Kato A. Na +/Cl - cotransporter 2 is not fish-specific and is widely found in amphibians, non-avian reptiles, and select mammals. Physiol Genomics 2023; 55:113-131. [PMID: 36645671 PMCID: PMC9988527 DOI: 10.1152/physiolgenomics.00143.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 09/19/2022] [Revised: 12/28/2022] [Accepted: 01/12/2023] [Indexed: 01/17/2023] Open
Abstract
Solute carrier 12 (Slc12) is a family of electroneutral cation-coupled chloride (Cl-) cotransporters. Na+/K+/2Cl- (Nkcc) and Na+/Cl- cotransporters (Ncc) belong to the Nkcc/Ncc subfamily. Human and mouse possess one gene for the Na+/Cl- cotransporter (ncc gene: slc12a3), whereas teleost fishes possess multiple ncc genes, slc12a3 (ncc1) and slc12a10 (ncc2), in addition to their species-specific paralogs. Amphibians and squamates have two ncc genes: slc12a3 (ncc1) and ncc3. However, the evolutionary relationship between slc12a10 and ncc3 remains unresolved, and the presence of slc12a10 (ncc2) in mammals has not been clarified. Synteny and phylogenetic analyses of vertebrate genome databases showed that ncc3 is the ortholog of slc12a10, and slc12a10 is present in most ray-finned fishes, coelacanths, amphibians, reptiles, and a few mammals (e.g., platypus and horse) but pseudogenized or deleted in birds, most mammals, and some ray-finned fishes (pufferfishes). This shows that slc12a10 is widely present among bony vertebrates and pseudogenized or deleted independently in multiple lineages. Notably, as compared with some fish that show varied slc12a10 tissue expression profile, spotted gar, African clawed frog, red-eared slider turtle, and horse express slc12a10 in the ovaries or premature gonads. In horse tissues, an unexpectedly large number of splicing variants for Slc12a10 have been cloned, many of which encode truncated forms of Slc12a10, suggesting that the functional constraints of horse slc12a10 are weakened, which may be in the process of becoming a pseudogene. Our results elaborate on the evolution of Nkcc/Ncc subfamily of Slc12 in vertebrates.NEW & NOTEWORTHY slc12a10 is not a fish-specific gene and is present in a few mammals (e.g., platypus and horse), non-avian reptiles, amphibians, but was pseudogenized or deleted in most mammals (e.g., human, mouse, cat, cow, and rhinoceros), birds, and some ray-finned fishes (pufferfishes).
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Affiliation(s)
- Toya Motoshima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Ayumi Nagashima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Chihiro Ota
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Haruka Oka
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Kohei Hosono
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Ingo Braasch
- Department of Integrative Biology, College of Natural Science, Michigan State University, East Lansing, Michigan, United States
| | - Hidenori Nishihara
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Akira Kato
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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Samanta MK, Gayen S, Harris C, Maclary E, Murata-Nakamura Y, Malcore RM, Porter RS, Garay PM, Vallianatos CN, Samollow PB, Iwase S, Kalantry S. Activation of Xist by an evolutionarily conserved function of KDM5C demethylase. Nat Commun 2022; 13:2602. [PMID: 35545632 PMCID: PMC9095838 DOI: 10.1038/s41467-022-30352-1] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 04/26/2022] [Indexed: 12/03/2022] Open
Abstract
XX female and XY male therian mammals equalize X-linked gene expression through the mitotically-stable transcriptional inactivation of one of the two X chromosomes in female somatic cells. Here, we describe an essential function of the X-linked homolog of an ancestral X-Y gene pair, Kdm5c-Kdm5d, in the expression of Xist lncRNA, which is required for stable X-inactivation. Ablation of Kdm5c function in females results in a significant reduction in Xist RNA expression. Kdm5c encodes a demethylase that enhances Xist expression by converting histone H3K4me2/3 modifications into H3K4me1. Ectopic expression of mouse and human KDM5C, but not the Y-linked homolog KDM5D, induces Xist in male mouse embryonic stem cells (mESCs). Similarly, marsupial (opossum) Kdm5c but not Kdm5d also upregulates Xist in male mESCs, despite marsupials lacking Xist, suggesting that the KDM5C function that activates Xist in eutherians is strongly conserved and predates the divergence of eutherian and metatherian mammals. In support, prototherian (platypus) Kdm5c also induces Xist in male mESCs. Together, our data suggest that eutherian mammals co-opted the ancestral demethylase KDM5C during sex chromosome evolution to upregulate Xist for the female-specific induction of X-inactivation.
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Affiliation(s)
- Milan Kumar Samanta
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
| | - Srimonta Gayen
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, Karnataka, 560012, India
| | - Clair Harris
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
| | - Emily Maclary
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Yumie Murata-Nakamura
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
| | - Rebecca M Malcore
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
| | - Robert S Porter
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
| | - Patricia M Garay
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
| | - Christina N Vallianatos
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
| | - Paul B Samollow
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Shigeki Iwase
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA
| | - Sundeep Kalantry
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor, MI, 48109-5618, USA.
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Coleman RA, Chee YE, Bond NR, Weeks A, Griffiths J, Serena M, Williams GA, Walsh CJ. Understanding and managing the interactive impacts of growth in urban land use and climate change on freshwater biota: A case study using the platypus (Ornithorhynchus anatinus). Glob Chang Biol 2022; 28:1287-1300. [PMID: 34854175 DOI: 10.1111/gcb.16015] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 11/12/2021] [Indexed: 06/13/2023]
Abstract
Globally, urban expansion and climate change interact to threaten stream ecosystems and are accelerating the loss of aquatic biodiversity. Waterway managers urgently need tools to understand the potential combined impacts of urbanization and climate change and to identify effective mitigating management interventions for protecting freshwater biota. We address this challenge using the semi-aquatic mammal the platypus (Ornithorhynchus anatinus) as a focal species. We developed high-resolution environmental spatial data for stream networks and spatially explicit habitat suitability models (HSMs) to explore the impact of threats and to identify the combination of management actions most likely to maintain or improve habitat suitability over the next 50 years in greater Melbourne, Australia. We developed and evaluated platypus HSMs (males-and-females and females-only) including validation using an independent environmental DNA data set. Platypus occurred more commonly in larger, cooler streams with greater catchment-weighted discharge, following periods of greater stream flow. They were positively associated with near-stream forest cover and negatively associated with annual air temperature and urban stormwater runoff. Extensive reductions in suitable platypus habitat are predicted to occur under urbanization and climate change scenarios, with the greatest threat expected from reduced streamflows. This emphasizes the importance of maintaining flow regimes as part of conserving platypus in the region; however, substantial additional benefit is predicted by concurrent riparian revegetation and urban stormwater management efforts (that also have the potential to contribute to the streamflow objectives). Provision of adequate streamflows in a future with increasing water demands and water security requirements will likely require creative integrated water management solutions. Our high-resolution stream network and HSMs have allowed predictions of potential range-shifts due to urban expansion and climate change impacts at management-relevant scales and at the whole-of-landscape scale. This has enabled systematic strategic planning, priority action planning and target setting in strategic policy development.
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Affiliation(s)
- Rhys A Coleman
- Melbourne Water Corporation, Docklands, Victoria, Australia
- School of Ecosystem and Forest Sciences, The University of Melbourne, Burnley, Victoria, Australia
| | - Yung En Chee
- School of Ecosystem and Forest Sciences, The University of Melbourne, Burnley, Victoria, Australia
| | - Nick R Bond
- Centre for Freshwater Ecosystems, La Trobe University, Wodonga, Victoria, Australia
| | - Andrew Weeks
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
- Cesar, Parkville, Victoria, Australia
| | | | - Melody Serena
- Australian Platypus Conservancy, Campbells Creek, Victoria, Australia
| | - Geoff A Williams
- Australian Platypus Conservancy, Campbells Creek, Victoria, Australia
| | - Christopher J Walsh
- School of Ecosystem and Forest Sciences, The University of Melbourne, Burnley, Victoria, Australia
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Bino G, Hawke T, Kingsford RT. Synergistic effects of a severe drought and fire on platypuses. Sci Total Environ 2021; 777:146137. [PMID: 33684764 DOI: 10.1016/j.scitotenv.2021.146137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
The strong inter-dependence between terrestrial and freshwater ecosystems, mediated by the character of vegetation and landscapes, can have significant impacts to freshwater species. A changing climate towards hotter and drier climates is already increasing fire frequencies and severity around the world. The platypus (Ornithorhynchus anatinus) is an iconic freshwater Australia species, facing increasing threats since European colonisation and with a distribution which coincides with fire prone areas. While some evidence suggest platypuses are resilience to fires, the combination of severe wildfires and reduced water availability may significantly impact platypus populations. In this short communication we investigated the effects of fire on platypus populations in two rivers, following an extreme drought, comparing burnt and unburnt in adjacent river catchments, with similar habitat and geomorphology. Findings suggests significantly low platypus numbers in burned sites compared to those on the unburnt river, as well as to known densities across the species' range. Whether the fires directly impacted platypuses remains undetermined but the timing of the fires as well as an extreme drought likely impacted recruitment as we did not record any juveniles on both rivers. Platypuses are increasingly under threat from direct and indirect human developments across much of their range and increased frequency and severity of fires and droughts will further strain the viability of platypus populations, particularly in small streams more likely to dry out. Improving the resilience of platypus populations and their freshwater environments to both droughts and fires needs to become a priority.
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Affiliation(s)
- Gilad Bino
- Centre for Ecosystem Science, School of Biological, Earth & Environmental Sciences, UNSW Sydney, 2052, NSW, Australia.
| | - Tahneal Hawke
- Centre for Ecosystem Science, School of Biological, Earth & Environmental Sciences, UNSW Sydney, 2052, NSW, Australia
| | - Richard T Kingsford
- Centre for Ecosystem Science, School of Biological, Earth & Environmental Sciences, UNSW Sydney, 2052, NSW, Australia
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11
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Bandiera G. Know thy platypus: The insidiousness of cognitive bias. Med Teach 2020; 42:708-709. [PMID: 31487476 DOI: 10.1080/0142159x.2019.1657820] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cognitive biases are omnipresent in medical practice. The danger of such biases rests largely on the fact that they are difficult to recognize and, by their nature, are positively reinforcing. This paper describes a real experience in which I discovered a classic example of cognitive bias to which I had fallen victim and the lengths I went to in order to preserve the bias. The paper concludes with some cautionary advice and mitigation strategies for educators and practitioners.
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Affiliation(s)
- Glen Bandiera
- Unity Health Toronto, University of Toronto, Toronto, Canada
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12
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Gofton AW, Loh SM, Barbosa AD, Paparini A, Gillett A, Macgregor J, Oskam CL, Ryan UM, Irwin PJ. A novel Ehrlichia species in blood and Ixodes ornithorhynchi ticks from platypuses (Ornithorhynchus anatinus) in Queensland and Tasmania, Australia. Ticks Tick Borne Dis 2017; 9:435-442. [PMID: 29284563 DOI: 10.1016/j.ttbdis.2017.12.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 12/14/2017] [Accepted: 12/14/2017] [Indexed: 01/21/2023]
Abstract
Worldwide, Ehrlichia spp. are emerging infectious organisms of domestic animals and people, however, most Ehrlichia spp. naturally infect wildlife reservoirs causing mainly asymptomatic infections. Australian ecosystems have been under-explored for these potentially pathogenic organisms, and recent studies have identified a range of novel Ehrlichia, and their sister genera, Anaplasma and 'Candidatus Neoehrlichia' species, from native Australian ticks. We used bacterial 16S rRNA (16S) next-generation sequencing and genus-specific PCR to profile the bacterial communities in platypus (Ornithorhynchus anatinus) blood samples and platypus ticks (Ixodes ornithorhynchi), and identified a high prevalence of Ehrlichia sequences. We also observed Ehrlichia-like intra-neutrophilic inclusions (morulae) in PCR-positive stained platypus blood films that were consistent in morphology with other Ehrlichia spp. Bayesian phylogenetic analysis of 16S (1343 bp), gltA (1004 bp), and groEL (1074 bp) gene sequences group the platypus Ehrlichia with 'Candidatus Ehrlichia khabarensis' from far-eastern Russia, and demonstrate that the platypus Ehrlichia is clearly distinct from all other Ehrlichia spp. Enough genetic divergence exists to delineate this platypus Ehrlichia as a separate species that we propose to designate 'Candidatus Ehrlichia ornithorhynchi'. There is no evidence that 'Candidatus Ehrlichia ornithorhynchi' causes disease in wild platypuses, however, the organism does seem to be widespread in Australia, being found in both Queensland and Tasmania. 'Candidatus Ehrlichia ornithorhynchi' is the second native Australian Ehrlichia described and adds to the rapidly growing diversity of recently described native Australian tick-borne bacteria.
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Affiliation(s)
- Alexander W Gofton
- Vector and Water-Borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
| | - Siew-May Loh
- Vector and Water-Borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia
| | - Amanda D Barbosa
- Vector and Water-Borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia; CAPES Foundation, Ministry of Education of Brazil, Brazilia, Distrito Federal, Brazil
| | - Andrea Paparini
- Vector and Water-Borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia
| | - Amber Gillett
- Australia Zoo Wildlife Hospital, Beerwah, Queensland, Australia
| | - James Macgregor
- Vector and Water-Borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia
| | - Charlotte L Oskam
- Vector and Water-Borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia
| | - Una M Ryan
- Vector and Water-Borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia
| | - Peter J Irwin
- Vector and Water-Borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia
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13
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Lawrence N. The Prime Minister and the platypus: A paradox goes to war. Stud Hist Philos Biol Biomed Sci 2012; 43:290-297. [PMID: 22326098 DOI: 10.1016/j.shpsc.2011.09.001] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 09/16/2011] [Indexed: 05/31/2023]
Abstract
In February 1943, in the midst of the Second World War, Prime Minister Winston Churchill demanded that a live duck-billed platypus be sent from Australia to Britain. A vigorous male was shipped off but died shortly before arrival in Britain. This request can only be understood if placed in the context of Churchill's passion for exotic pets as well as the rich history of aristocratic menageries and live diplomatic gifts. Obtaining an animal hitherto unseen alive in Europe would have been a great zoological achievement for London Zoo and secured British authority in heated historical taxonomical debates. This zoological triumph, coupled with accomplishing an extravagant enterprise in the middle of war-time austerity would have boosted public morale. Most importantly, despite its death, the platypus, served as a token for mediating the soured relations between Australia and Britain. Churchill's platypus provides a unique case of animal collecting that incorporates effects on international diplomacy and public relations along with a great private eccentricity and passion.
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Affiliation(s)
- Natalie Lawrence
- St. John's College, Cambridge University, Cambridge CB2 1TP, UK.
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14
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Nieminen P, Rouvinen-Watt K, Kapiainen S, Harris L, Mustonen AM. Molecular evolution of adiponectin in Carnivora and its mRNA expression in relation to hepatic lipidosis. Gen Comp Endocrinol 2010; 168:307-11. [PMID: 20553720 DOI: 10.1016/j.ygcen.2010.05.010] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 05/18/2010] [Accepted: 05/23/2010] [Indexed: 10/19/2022]
Abstract
Adiponectin is a novel adipocyte-derived hormone with low circulating concentrations and/or mRNA expression in obesity and non-alcoholic fatty liver disease (NAFLD). The adiponectin mRNA of several Carnivora species was sequenced to enable further gene expression studies in this clade with potential experimental species to examine the connections of hypoadiponectinemia to hepatic lipidosis. In addition, adiponectin mRNA expression was studied in the retroperitoneal fat of the American mink (Neovison vison), as hepatic lipidosis with close similarities to NAFLD can be rapidly induced to the species by fasting. The mRNA expression was determined after overnight-7d of food deprivation and 28d of re-feeding and correlated to the liver fat %. The homologies between the determined carnivoran mRNA sequences and that of the domestic dog were 92.2-99.1%. As the mRNA expression was not affected by short-term fasting and did not correlate with the liver fat %, there seems to be no clear connection between adiponectin and the development of lipidosis in the American mink. In the future, the obtained sequences can be utilized in further studies of adiponectin expression in comparative endocrinology.
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Affiliation(s)
- Petteri Nieminen
- Faculty of Health Sciences, School of Medicine, Institute of Biomedicine/Anatomy, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland.
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15
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Ponczek MB. [The contact factors of hemostasis: examination of molecular evolution and new therapeutic perspectives]. Postepy Biochem 2010; 56:67-74. [PMID: 20499683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Enterprises of whole genome sequencing together with information technology progress enable reconstruction of blood clotting evolution by bioinformatic methods. It together offers a base to conclude that the contact phase of vertebrate blood coagulation is evolutionary young and shaped merely before divergence of marsupial and placental mammals. Amphibians, birds and platypus own a single gene corresponding to the predecessor of factor XI and plasma prekallikrein. The opossum has both PK and FXI like eutherian mammals. FXII appears first in amphibians, it is present in platypus and opossum, but disappears in lineage leading to birds, probably by gene loss. The last findings brought to live the intrinsic coagulation pathway as it was discovered that FXII-knockout mice were protected from experimentally induced thrombosis, with no changes of proper clotting. The contact proteases may be a target for new antithrombotic therapies.
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Affiliation(s)
- Michał Błazej Ponczek
- Department of General Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, 12/16 Banacha St., 90-237, Lodz, Poland.
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16
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Lee YR, Tsunekawa K, Moon MJ, Um HN, Hwang JI, Osugi T, Otaki N, Sunakawa Y, Kim K, Vaudry H, Kwon HB, Seong JY, Tsutsui K. Molecular evolution of multiple forms of kisspeptins and GPR54 receptors in vertebrates. Endocrinology 2009; 150:2837-46. [PMID: 19164475 DOI: 10.1210/en.2008-1679] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Kisspeptin and its receptor GPR54 play important roles in mammalian reproduction and cancer metastasis. Because the KiSS and GPR54 genes have been identified in a limited number of vertebrate species, mainly in mammals, the evolutionary history of these genes is poorly understood. In the present study, we have cloned multiple forms of kisspeptin and GPR54 cDNAs from a variety of vertebrate species. We found that fish have two forms of kisspeptin genes, KiSS-1 and KiSS-2, whereas Xenopus possesses three forms of kisspeptin genes, KiSS-1a, KiSS-1b, and KiSS-2. The nonmammalian KiSS-1 gene was found to be the ortholog of the mammalian KiSS-1 gene, whereas the KiSS-2 gene is a novel form, encoding a C-terminally amidated dodecapeptide in the Xenopus brain. This study is the first to identify a mature form of KiSS-2 product in the brain of any vertebrate. Likewise, fish possess two receptors, GPR54-1 and GPR54-2, whereas Xenopus carry three receptors, GPR54-1a, GPR54-1b, and GPR54-2. Sequence identity and genome synteny analyses indicate that Xenopus GPR54-1a is a human GPR54 ortholog, whereas Xenopus GPR54-1b is a fish GPR54-1 ortholog. Both kisspeptins and GPR54s were abundantly expressed in the Xenopus brain, notably in the hypothalamus, suggesting that these ligand-receptor pairs have neuroendocrine and neuromodulatory roles. Synthetic KiSS-1 and KiSS-2 peptides activated GPR54s expressed in CV-1 cells with different potencies, indicating differential ligand selectivity. These data shed new light on the molecular evolution of the kisspeptin-GPR54 system in vertebrates.
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Affiliation(s)
- Yeo Reum Lee
- Laboratory of G Protein-Coupled Receptors, Graduate School of Medicine, Korea University, Seoul, Korea
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17
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Rowe T, Rich TH, Vickers-Rich P, Springer M, Woodburne MO. The oldest platypus and its bearing on divergence timing of the platypus and echidna clades. Proc Natl Acad Sci U S A 2008; 105:1238-42. [PMID: 18216270 PMCID: PMC2234122 DOI: 10.1073/pnas.0706385105] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2007] [Indexed: 11/18/2022] Open
Abstract
Monotremes have left a poor fossil record, and paleontology has been virtually mute during two decades of discussion about molecular clock estimates of the timing of divergence between the platypus and echidna clades. We describe evidence from high-resolution x-ray computed tomography indicating that Teinolophos, an Early Cretaceous fossil from Australia's Flat Rocks locality (121-112.5 Ma), lies within the crown clade Monotremata, as a basal platypus. Strict molecular clock estimates of the divergence between platypus and echidnas range from 17 to 80 Ma, but Teinolophos suggests that the two monotreme clades were already distinct in the Early Cretaceous, and that their divergence may predate even the oldest strict molecular estimates by at least 50%. We generated relaxed molecular clock models using three different data sets, but only one yielded a date overlapping with the age of Teinolophos. Morphology suggests that Teinolophos is a platypus in both phylogenetic and ecological aspects, and tends to contradict the popular view of rapid Cenozoic monotreme diversification. Whereas the monotreme fossil record is still sparse and open to interpretation, the new data are consistent with much slower ecological, morphological, and taxonomic diversification rates for monotremes than in their sister taxon, the therian mammals. This alternative view of a deep geological history for monotremes suggests that rate heterogeneities may have affected mammalian evolution in such a way as to defeat strict molecular clock models and to challenge even relaxed molecular clock models when applied to mammalian history at a deep temporal scale.
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Affiliation(s)
- Timothy Rowe
- *Jackson School of Geosciences, University of Texas, C1100, Austin, TX 78712
| | - Thomas H. Rich
- Museum Victoria, PO Box 666, Melbourne, Victoria 3001, Australia
- School of Geosciences, PO Box 28E, Monash University, Victoria 3800, Australia
| | | | - Mark Springer
- Department of Biology, University of California, Riverside, CA 92521; and
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18
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Grafodatskaya D, Rens W, Wallis MC, Trifonov V, O'Brien PCM, Clarke O, Graves JAM, Ferguson-Smith MA. Search for the sex-determining switch in monotremes: mapping WT1, SF1, LHX1, LHX2, FGF9, WNT4, RSPO1 and GATA4 in platypus. Chromosome Res 2007; 15:777-85. [PMID: 17717721 DOI: 10.1007/s10577-007-1161-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 05/29/2007] [Accepted: 05/29/2007] [Indexed: 10/22/2022]
Abstract
The duck-billed platypus has five pairs of sex chromosomes, but there is no information about the primary sex-determining switch in this species. As there is no apparent SRY orthologue in platypus, another gene must acquire the function of a key regulator of the gonadal male or female fate. SOX9 was ruled out from being this key regulator as it maps to an autosome in platypus. To check whether other genes in mammalian gonadogenesis could be the primary switch in monotremes, we have mapped a number of candidates in platypus. We report here the autosomal location of WT1, SF1, LHX1, LHX9, FGF9, WNT4 and RSPO1 in platypus, thus excluding these from being key regulators of sex determination in this species. We found that GATA4 maps to sex chromosomes Y1 and X2; however, it lies in the pairing region shown by chromosome painting to be homologous, so is unlikely to be either male-specific or differentially dosed in male and female.
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Affiliation(s)
- Daria Grafodatskaya
- Cambridge Resource Centre for Comparative Genomics, Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 OES, UK
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19
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Abstract
Vertebrate vomeronasal chemoreception plays important roles in many aspects of an organism's daily life, such as mating, territoriality, and foraging. Vomeronasal type 1 receptors (V1Rs) and vomeronasal type 2 receptors (V2Rs), 2 large families of G protein-coupled receptors, serve as vomeronasal receptors to bind to various pheromones and odorants. Contrary to the previous observations of reduced olfaction in aquatic and semiaquatic mammals, we here report the surprising finding that the platypus, a semiaquatic monotreme, has the largest V1R repertoire and nearly largest combined repertoire of V1Rs and V2Rs of all vertebrates surveyed, with 270 intact genes and 579 pseudogenes in the V1R family and 15 intact genes, 55 potentially intact genes, and 57 pseudogenes in the V2R family. Phylogenetic analysis shows a remarkable expansion of the V1R repertoire and a moderate expansion of the V2R repertoire in platypus since the separation of monotremes from placentals and marsupials. Our results challenge the view that olfaction is unimportant to aquatic mammals and call for further study into the role of vomeronasal reception in platypus physiology and behavior.
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20
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Zhao Z, Zhao Y, Pan-Hammarström Q, Liu W, Liu Z, Zhao Y, Li N, Hammarström L. Physical mapping of the giant panda immunoglobulin heavy chain constant region genes. Dev Comp Immunol 2007; 31:1034-49. [PMID: 17368536 DOI: 10.1016/j.dci.2007.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 01/08/2007] [Accepted: 01/11/2007] [Indexed: 05/14/2023]
Abstract
We constructed a giant panda bacterial artificial chromosome (BAC) genomic library and isolated a BAC clone containing all the immunoglobulin heavy chain genes. The sequences of these genes were determined, revealing that the deduced panda immunoglobulin heavy chain constant regions (IGHC) are structurally similar to their counterparts in other mammalian species and phylogenetic analysis suggests that the panda immunoglobulins are evolutionarily more close to their counterparts in dogs. Both the panda IgG1 and IgG2 show a unique four amino acids-deletion that has not been observed in any other species to date. The entire panda IGHC gene locus shows an mu-4 kb-delta-39 kb-gamma1-27 kb-gamma2-13 kb-epsilon-14 kb-alpha gene order. It is the most compact mammalian IGHC locus known thus far, encompassing only 120 kb of DNA. Fluorescent in situ hybridization showed that the panda locus is localized on tip of the short arm of chromosome 12.
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Affiliation(s)
- Zhihui Zhao
- State Key Laboratories for AgroBiotechnology, College of Biological Sciences, China Agricultural University, Beijing, PR China, and Department of Laboratory Medicine, Karolinska University Hospital at Huddinge, Stockholm, Sweden
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21
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Ashwell KWS, Lajevardi SE, Cheng G, Paxinos G. The hypothalamic supraoptic and paraventricular nuclei of the echidna and platypus. Brain Behav Evol 2006; 68:197-217. [PMID: 16809908 DOI: 10.1159/000094358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2005] [Accepted: 03/30/2006] [Indexed: 11/19/2022]
Abstract
The monotremes are an intriguing group of mammals that have major differences in their reproductive physiology and lactation from therian mammals. Monotreme young hatch from leathery skinned eggs and are nourished by milk secreted onto areolae rather than through nipples. Parturition and lactation are in part controlled through the paraventricular and supraoptic nuclei of the hypothalamus. We have used Nissl staining, enzyme histochemistry, immunohistochemistry for tyrosine hydroxylase, calbindin, oxytocin, neurophysin and non-phosphorylated neurofilament protein, and carbocyanine dye tracing techniques to examine the supraoptic and paraventricular nuclei and the course of the hypothalamo-neurohypophysial tract in two monotremes: the short-beaked echidna (Tachyglossus aculeatus) and the platypus (Ornithorhynchus anatinus). In both monotremes, the supraoptic nucleus consisted of loosely packed neurons, mainly in the retrochiasmatic position. In the echidna, the paraventricular nucleus was quite small, but had similar chemoarchitectural features to therians. In the platypus, the paraventricular nucleus was larger and appeared to be part of a stream of magnocellular neurons extending from the paraventricular nucleus to the retrochiasmatic supraoptic nucleus. Immunohistochemistry for non-phosphorylated neurofilament protein and carbocyanine dye tracing suggested that hypothalamo-neurohypophysial tract neurons in the echidna lie mainly in the retrochiasmatic supraoptic and lateral hypothalamic regions, but most neurophysin and oxytocin immunoreactive neurons in the echidna were found in the paraventricular, lateral hypothalamus and supraoptic nuclei and most oxytocinergic neurons in the platypus were distributed in a band from the paraventricular nucleus to the retrochiasmatic supraoptic nucleus. The small size of the supraoptic nucleus in the two monotremes might reflect functional aspects of monotreme lactation.
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Affiliation(s)
- Ken W S Ashwell
- Department of Anatomy, School of Medical Sciences, The University of New South Wales, Sydney, Australia.
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22
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Hoppe R, Lambert TD, Samollow PB, Breer H, Strotmann J. Evolution of the "OR37" subfamily of olfactory receptors: a cross-species comparison. J Mol Evol 2006; 62:460-72. [PMID: 16547640 DOI: 10.1007/s00239-005-0093-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [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] [Received: 04/21/2005] [Accepted: 11/17/2005] [Indexed: 01/09/2023]
Abstract
Genes encoding the olfactory receptors of the "OR37" subfamily of the mouse are characterized by special features including a clustered expression pattern, assembly in two distinct gene clusters, and highly conserved putative promoter motifs. Mining the rat and dog databases revealed that these two species possess highly conserved clusters of OR37 genes at two syntenic genomic loci. In a prototherian mammal, the platypus (Ornithorhynchus anatinus), none of the characteristic OR37 genes were found. Examination of a metatherian mammal, the gray short-tailed opossum (Monodelphis domestica) revealed seven canonical OR37 genes, all phylogenetically related to cluster II genes and also organized similar to cluster II of eutherian species. In addition, their 5' upstream regions comprised sequence motifs related to the putative regulatory sequences of cluster II genes. Typical cluster I OR37 genes were identified only in the eutherian mammals examined, including the evolutionary ancient anteater, wherein OR37 genes related to both clusters were present. Together, these results reveal novel information concerning the phylogenetic origin and important evolutionary steps of the mammalian-specific OR37 olfactory receptor family.
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Affiliation(s)
- Reiner Hoppe
- Institute of Physiology, University of Hohenheim, Garbenstrasse 30, 70593, Stuttgart, Germany
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23
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Torres A, Tsampazi C, Geraghty D, Bansal P, Alewood P, Kuchel P. D-amino acid residue in a defensin-like peptide from platypus venom: effect on structure and chromatographic properties. Biochem J 2006; 391:215-20. [PMID: 16033333 PMCID: PMC1276918 DOI: 10.1042/bj20050900] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The recent discovery that the natriuretic peptide OvCNPb (Ornithorhynchus venom C-type natriuretic peptide B) from platypus (Ornithorynchus anatinus) venom contains a D-amino acid residue suggested that other D-amino-acid-containing peptides might be present in the venom. In the present study, we show that DLP-2 (defensin-like peptide-2), a 42-amino-acid residue polypeptide in the platypus venom, also contains a D-amino acid residue, D-methionine, at position 2, while DLP-4, which has an identical amino acid sequence, has all amino acids in the L-form. These findings were supported further by the detection of isomerase activity in the platypus gland venom extract that converts DLP-4 into DLP-2. In the light of this new information, the tertiary structure of DLP-2 was recalculated using a new structural template with D-Met2. The structure of DLP-4 was also determined in order to evaluate the effect of a D-amino acid at position 2 on the structure and possibly to explain the large retention time difference observed for the two molecules in reverse-phase HPLC. The solution structures of the DLP-2 and DLP-4 are very similar to each other and to the earlier reported structure of DLP-2, which assumed that all amino acids were in the L-form. Our results suggest that the incorporation of the D-amino acid at position 2 has minimal effect on the overall fold in solution.
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Affiliation(s)
- Allan M. Torres
- *School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia
| | - Chryssanthi Tsampazi
- *School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia
| | - Dominic P. Geraghty
- †School of Biomedical Science, University of Tasmania, Launceston, Tas 7250, Australia
| | - Paramjit S. Bansal
- ‡Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld 4072, Australia
| | - Paul F. Alewood
- ‡Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld 4072, Australia
| | - Philip W. Kuchel
- *School of Molecular and Microbial Biosciences, University of Sydney, NSW 2006, Australia
- To whom correspondence should be addressed (email )
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Alibardi L, Tschachler E, Eckhart L. Distribution of caspase-14 in epidermis and hair follicles is evolutionarily conserved among mammals. ACTA ACUST UNITED AC 2005; 286:962-73. [PMID: 16142807 DOI: 10.1002/ar.a.20234] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Caspase-14, a member of the caspase family of cysteine proteases, is almost exclusively expressed in the epidermis. Studies on human and mouse cells and tissues have implicated caspase-14 in terminal differentiation of epidermal keratinocytes and in the formation of the stratum corneum. Here we investigated evolutionary aspects of the role of caspase-14 by analyzing its distribution in the epidermis and hair follicles of representative species of placental mammals, marsupials, and monotremes. Immunocytochemical staining showed that caspase-14 is consistently expressed in the granular and corneous layer of the epidermis of all mammalian species investigated. Ultrastructural analysis using gold-labeled anticaspase-14 antibodies revealed that caspase-14 is associated preferentially with keratin bundles and amorphous material of keratohyalin granules, but is also present in nuclei of transitional cells of the granular layer and in corneocytes. In hair follicles, caspase-14 was diffusely present in cornifying cells of the outer root sheath, in the companion layer, and, most abundantly, in the inner root sheath of all mammalian species here analyzed. In Henle and Huxley layers of the inner root sheath, labeling was seen in nuclei and, more diffusely, among trichohyalin granules of cornifying cells. In summary, the tissue expression pattern and the intracellular localization of caspase-14 are highly conserved among diverse mammalian species, suggesting that this enzyme is involved in a molecular process that appeared early in the evolution of mammalian skin. The association of caspase-14 with keratohyalin and trichohyalin granules may indicate a specific role of caspase-14 in the maturation of these keratinocyte-specific structures.
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Abstract
There is limited information regarding the kinetics of antibody responses exhibited by the platypus and the echidna in response to a T cell dependent antigen. In this preliminary study a platypus, an echidna and a rabbit were inoculated with sheep red blood cells to compare their antibody responses and kinetics. The antibody titres, produced by the platypus and echidna, were less than those elicited in the rabbit. Furthermore, the echidna and platypus exhibited a weak secondary response. This was most likely due to a failure of the platypus and echidna to undergo the characteristic IgM to IgG isotype switch following second antigen exposure. The conformational structure of these antibodies may differ from eutherian antibodies. This was further supported by a heat sensitivity experiment that indicated that these antibodies are more labile than rabbit immunoglobulins and therefore structurally less stable.
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Affiliation(s)
- Eileen V Wronski
- School of Medicine, University of Tasmania, Private Bag 72, Hobart, Tasmania, 7001 Australia.
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van Rheede T, Amons R, Stewart N, de Jong WW. Lactate dehydrogenase A as a highly abundant eye lens protein in platypus (Ornithorhynchus anatinus): upsilon (upsilon)-crystallin. Mol Biol Evol 2003; 20:994-8. [PMID: 12716980 DOI: 10.1093/molbev/msg116] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Vertebrate eye lenses mostly contain two abundant types of proteins, the alpha-crystallins and the beta/gamma-crystallins. In addition, certain housekeeping enzymes are highly expressed as crystallins in various taxa. We now observed an unusual approximately 41-kd protein that makes up 16% to 18% of the total protein in the platypus eye lens. Its cDNA sequence was determined, which identified the protein as muscle-type lactate dehydrogenase A (LDH-A). It is the first observation of LDH-A as a crystallin, and we designate it upsilon (upsilon)-crystallin. Interestingly, the related heart-type LDH-B occurs as an abundant lens protein, known as epsilon-crystallin, in many birds and crocodiles. Thus, two members of the ldh gene family have independently been recruited as crystallins in different higher vertebrate lineages, suggesting that they are particularly suited for this purpose in terms of gene regulatory or protein structural properties. To establish whether platypus LDH-A/upsilon-crystallin has been under different selective constraints as compared with other vertebrate LDH-A sequences, we reconstructed the vertebrate ldh-a gene phylogeny. No conspicuous rate deviations or amino acid replacements were observed.
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Affiliation(s)
- Teun van Rheede
- Department of Biochemistry, University of Nijmegen, Nijmegen, The Netherlands
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27
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Torres AM, Menz I, Alewood PF, Bansal P, Lahnstein J, Gallagher CH, Kuchel PW. D-Amino acid residue in the C-type natriuretic peptide from the venom of the mammal, Ornithorhynchus anatinus, the Australian platypus. FEBS Lett 2002; 524:172-6. [PMID: 12135762 DOI: 10.1016/s0014-5793(02)03050-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The C-type natriuretic peptide from the platypus venom (OvCNP) exists in two forms, OvCNPa and OvCNPb, whose amino acid sequences are identical. Through the use of nuclear magnetic resonance, mass spectrometry, and peptidase digestion studies, we discovered that OvCNPb incorporates a D-amino acid at position 2 in the primary structure. Peptides containing a D-amino acid have been found in lower forms of organism, but this report is the first for a D-amino acid in a biologically active peptide from a mammal. The result implies the existence of a specific isomerase in the platypus that converts an L-amino acid residue in the protein to the D-configuration.
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Affiliation(s)
- Allan M Torres
- School of Molecular and Microbial Biosciences, University of Sydney, NSW, Australia
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28
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Torres AM, Alewood D, Alewood PF, Gallagher CH, Kuchel PW. Conformations of platypus venom C-type natriuretic peptide in aqueous solution and sodium dodecyl sulfate micelles. Toxicon 2002; 40:711-9. [PMID: 12175607 DOI: 10.1016/s0041-0101(01)00266-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [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: 10/27/2022]
Abstract
Nuclear magnetic resonance spectroscopy was used to investigate the conformations of the platypus venom C-type natriuretic peptide A (OvCNPa) in aqueous solutions and in solutions containing sodium dodecyl sulfate (SDS) micelles. The chemically synthesized OvCNPa showed a substantial decrease in flexibility in aqueous solution at 10 degrees C, allowing the observation of medium- and long-range nuclear Overhauser enhancement (NOE) connectivities. Three-dimensional structures calculated using these data showed flexible and reasonably well-defined regions, the locations of which were similar in the two solvents. In aqueous solution, the linear part that spans residues 3-14 was basically an extended conformation while the cyclic portion, defined by residues 23-39, contained a series of beta-turns. The overall shape of the cyclic portion was similar to that observed for an atrial natriuretic peptide (ANP) variant in aqueous solution. OvCNPa adopted a different conformation in SDS micelles wherein the N-terminal region, defined by residues 2-10, was more compact, characterised by turns and a helix, while the cyclic region had turns and an overall shape that was fundamentally different from those structures observed in aqueous solution. The hydrophobic cluster, situated at the centre of the ring of the structure in aqueous solution, was absent in the structure in the presence of SDS micelles. Thus, OvCNPa interacts with SDS micelles and can possibly form ion-channels in cell membranes.
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Affiliation(s)
- Allan M Torres
- Department of Biochemistry, University of Sydney, Sydney, NSW 2006, Australia
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29
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Munday BL, Stewart NJ, Södergren A. Variations in residues of persistent organic pollutants in a platypus (Ornythorhynchus anatinus) at consecutive samplings. Aust Vet J 2002; 80:299-300. [PMID: 12074313 DOI: 10.1111/j.1751-0813.2002.tb10849.x] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B L Munday
- School of Biomedical Science, University of Tasmania, Launceston
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30
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de Plater GM, Milburn PJ, Martin RL. Venom from the platypus, Ornithorhynchus anatinus, induces a calcium-dependent current in cultured dorsal root ganglion cells. J Neurophysiol 2001; 85:1340-5. [PMID: 11248005 DOI: 10.1152/jn.2001.85.3.1340] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The platypus (Ornithorhynchus anatinus), a uniquely Australian species, is one of the few living venomous mammals. Although envenomation of humans by many vertebrate and invertebrate species results in pain, this is often not the principal symptom of envenomation. However, platypus envenomation results in an immediate excruciating pain that develops into a very long-lasting hyperalgesia. We have previously shown that the venom contains a C-type natriuretic peptide that causes mast cell degranulation, and this probably contributes to the development of the painful response. Now we demonstrate that platypus venom has a potent action on putative nociceptors. Application of the venom to small to medium diameter dorsal root ganglion cells for 10 s resulted in an inward current lasting several minutes when the venom was diluted in buffer at pH 6.1 but not at pH 7.4. The venom itself has a pH of 6.3. The venom activated a current with a linear current-voltage relationship between -100 and -25 mV and with a reversal potential of -11 mV. Ion substitution experiments indicate that the current is a nonspecific cationic current. The response to the venom was blocked by the membrane-permeant Ca(2+)-ATPase inhibitor, thapsigargin, and by the tyrosine- and serine-kinase inhibitor, k252a. Thus the response appears to be dependent on calcium release from intracellular stores. The identity of the venom component(s) that is responsible for the responses we have described is yet to be determined but is probably not the C-type natriuretic peptide or the defensin-like peptides that are present in the venom.
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Affiliation(s)
- G M de Plater
- Division of Neuroscience, Australian National University, Canberra, ACT 0200, Australia
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31
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Elston GN, Manger PR, Pettigrew JD. Morphology of pyramidal neurones in cytochrome oxidase modules of the S-I bill representation of the platypus. Brain Behav Evol 2000; 53:87-101. [PMID: 9933785 DOI: 10.1159/000006585] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The primary somatosensory cortex of the platypus (Ornithorhynchus anatinus) is characterized by a distinct array of functionally specific cytochrome oxidase (CO) modules, forming alternate CO-rich and CO-poor bands. In the current study, we undertook to establish whether the cellular morphology of layer V pyramidal neurones reflects this modular organization. To this end, we injected neurones with Lucifer Yellow in 250 microm thick, flat-mounted cortical slices and processed the tissue to reveal a light-stable reaction product. By aligning blood vessels in serial sections in which we injected individual neurones with sections processed for CO, we were able to establish the exact location of injected cells with respect to the pattern of CO bands. Pyramidal neurones in the CO-poor bands (which are responsive to both mechano- and electroreceptive stimuli) had basal dendritic fields that were larger than those in the CO-rich bands. The large basal dendritic fields of layer V pyramidal neurones in the CO-poor bands may allow for integration of a greater number of more diverse inputs, thus allowing for averaging of stimuli to improve the signal-to-noise ratio or enhance spatial discrimination of peripheral stimuli. In some instances, neurones located within approximately 100 microm of the boundaries of the CO bands had dendritic fields that appeared to conform to the CO bands, the dendrites preferentially arborizing within a single band and avoiding the neighbouring band. However, the bias was not absolute, as we observed many examples of cells with dendrites that crossed the boundary between bands. Furthermore, many cells had dendrites that showed distinct dendritic bias that bore no obvious relationship to the CO boundaries.
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Affiliation(s)
- G N Elston
- Vision, Touch and Hearing Research Centre, Department of Physiology and Pharmacology, The University of Queensland, Brisbane, Australia.
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32
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Torres AM, de Plater GM, Doverskog M, Birinyi-Strachan LC, Nicholson GM, Gallagher CH, Kuchel PW. Defensin-like peptide-2 from platypus venom: member of a class of peptides with a distinct structural fold. Biochem J 2000; 348 Pt 3:649-56. [PMID: 10839998 PMCID: PMC1221109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The venom of the male Australian duck-billed platypus contains a family of four polypeptides of appox. 5 kDa, which are referred to as defensin-like peptides (DLPs). They are unique in that their amino acid sequences have no significant similarities to those of any known peptides; however, the tertiary structure of one of them, DLP-1, has recently been shown to be similar to beta-defensin-12 and to the sodium neurotoxin peptide ShI (Stichodactyla helianthus neurotoxin I). Although DLPs are the major peptides in the platypus venom, little is known about their biological roles. In this study, we determined the three-dimensional structure of DLP-2 by NMR spectroscopy, with the aim of gaining insights into the natural function of the DLPs in platypus venom. The DLP-2 structure was found to incorporate a short helix that spans residues 9-12, and an antiparallel beta-sheet defined by residues 15-18 and 37-40. The overall fold and cysteine-pairing pattern of DLP-2 were found to be similar to those of DLP-1, and hence beta-defensin-12; however, the sequence similarities between the three molecules are relatively small. The distinct structural fold of the DLP-1, DLP-2, and beta-defensin-12 is based upon several key residues that include six cysteines. DLP-3 and DLP-4 are also likely to be folded similarly since they have high sequence similarity with DLP-2. The DLPs, and beta-defensin-12 may thus be grouped together into a class of polypeptide molecules which have a common or very similar global fold. The fact that the DLPs did not display antimicrobial, myotoxic, or cell-growth-promoting activities implies that the nature of the side chains in this group of peptides is likely to play an important role in defining the biological function(s).
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Affiliation(s)
- A M Torres
- Department of Biochemistry, University of Sydney, NSW 2006, Australia
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33
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Abstract
The lipid bilayer technique is used to examine the biophysical properties of anion and cation channels frequently formed by platypus (Ornithorhynchus anatinus) venom (OaV). The OaV-formed anion channel in 250/50 mm KCl cis/trans has a maximum conductance of 857 +/- 23 pS (n = 5) in 250/50 mm KCl cis/trans. The current-voltage relationship of this channel shows strong inward rectification. The channel activity undergoes time-dependent inactivation that can be removed by depolarizing voltage steps more positive than the reversal potential for chloride, E(Cl), (+40 mV). The reversal potential of the OaV-formed slow current activity in 250/50 mm KCl cis/trans is close to the potassium equilibrium potential (E(K)) of -40 mV. The conductance values for the slow channel are 22.5 +/- 2.6 pS and 41.38 +/- 4.2 pS in 250/50 and 750/50 mm cis/trans, respectively. The gating kinetics of the slow ion channels are voltage-dependent. The channel open probability (P(o)) is between 0.1 and 0.8 at potentials between 0 and +140 mV. The channel frequency (F(o)) increases with depolarizing voltages between 0 and +140 mV, whereas mean open time (T(o)) and mean closed time (T(c)) decrease. Ion substitution experiments of the cis solution show that the channel has conductance values of 21.47 +/- 2. 3 and 0.53 +/- 0.1 pS in 250 mm KCl and choline Cl, respectively. The amplitude of the single channel current is dependent on [K(+)](cis) and the current reversal potential (E(rev)) responds to increases in [K(+)](cis) by shifting to more negative voltages. The increase in current amplitude as a function of increasing [K(+)](cis) can be best described by a third order polynomial fit. At +140 mV, the values of the maximal single channel conductance (gamma(max)) and the concentration for half maximal gamma (K(s)) are 38.6 pS and 380 mm and decline to 15.76 pS and 250 mm at 0 mV, respectively. The ion selectivity of the channel to K(+), Na(+), Cs(+) and choline(+) was determined in ion substitution experiments. The permeability values for P(K(+)):P(Na(+)):P(Cs(+)):P(choline(+)) were 1:1:0.63:0.089, respectively. On the other hand, the activity of the slow channel was eliminated (Fig. 7B). The slow channel was reversibly inhibited by [TEA(+)](trans) and the half-maximal inhibitory concentration (K(i)) was approximately 48 mm.
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Affiliation(s)
- J I Kourie
- Membrane Transport Group, Department of Chemistry, The Faculties, The Australian National University, Canberra City, ACT, 0200 Australia
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Wade MA, Lin M. A 33 kDa molecular marker of sperm acrosome differentiation and maturation in the tammar wallaby (Macropus eugenii). J Reprod Fertil 1999; 117:79-88. [PMID: 10645248 DOI: 10.1530/jrf.0.1170079] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study was undertaken to identify potential molecular markers of acrosomal biogenesis and post-testicular maturation in marsupials, using the tammar wallaby as a model species. A two-step sperm extraction procedure yielded two protein extracts of apparent acrosomal origin and a tail extract. The extracts were analysed by SDS-PAGE under reducing conditions. Several prominent polypeptide bands (45, 38 and 33 kDa) appeared common to both acrosomal extracts. Antiserum raised against the 33 kDa polypeptide from the inner acrosomal membrane matrix (IAMM) extract showed immunoreactivity with 45, 38 and 33 kDa polypeptides in both acrosomal extracts, indicating that the 33 kDa polypeptide was related to the proteins in the 45 and 38 kDa bands. Therefore, the antiserum was used as a molecular probe. Indirect immuno-fluorescence indicated that the acrosome was the major location of the 33 kDa polypeptide. This contention was confirmed by ultrastructural study: immunogold labelling indicated that the 33 kDa polypeptide associated with acrosomal matrix components throughout acrosomal development in the testes and throughout post-testicular maturation in the epididymis. The label clearly delineated the changing morphology of the maturing marsupial acrosome. This is the first study to use immunocytochemical techniques to chart testicular and post-testicular development of any sperm organelle in a marsupial. As a result of this study, a 33 kDa molecular marker of marsupial acrosome differentiation and maturation has been identified. It may be possible to chart similar events in other marsupial species and identify opportunities for manipulating fertility.
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Affiliation(s)
- M A Wade
- Department of Biological Sciences, University of Newcastle, Callaghan, NSW, Australia
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35
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Torres AM, Wang X, Fletcher JI, Alewood D, Alewood PF, Smith R, Simpson RJ, Nicholson GM, Sutherland SK, Gallagher CH, King GF, Kuchel PW. Solution structure of a defensin-like peptide from platypus venom. Biochem J 1999; 341 ( Pt 3):785-94. [PMID: 10417345 PMCID: PMC1220419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Three defensin-like peptides (DLPs) were isolated from platypus venom and sequenced. One of these peptides, DLP-1, was synthesized chemically and its three-dimensional structure was determined using NMR spectroscopy. The main structural elements of this 42-residue peptide were an anti-parallel beta-sheet comprising residues 15-18 and 37-40 and a small 3(10) helix spanning residues 10-12. The overall three-dimensional fold is similar to that of beta-defensin-12, and similar to the sodium-channel neurotoxin ShI (Stichodactyla helianthus neurotoxin I). However, the side chains known to be functionally important in beta-defensin-12 and ShI are not conserved in DLP-1, suggesting that it has a different biological function. Consistent with this contention, we showed that DLP-1 possesses no anti-microbial properties and has no observable activity on rat dorsal-root-ganglion sodium-channel currents.
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Affiliation(s)
- A M Torres
- Department of Biochemistry, University of Sydney, NSW 2006, Australia
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36
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Abstract
The lipid bilayer technique was used to characterize the Ca(2+) dependence of a fast K(+) channel formed by a synthetic 17-amino acid segment [OaCNP-39-(1-17)] of a 39-amino acid C-type natriuretic peptide (OaCNP-39) found in platypus (Ornithorhynchus anatinus) venom (OaV). The OaCNP-39-(1-17)-formed K(+) channel was reversibly dependent on 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-buffered cis (cytoplasmic) Ca(2+) concentration ([Ca(2+)](cis)). The channel was fully active when [Ca(2+)](cis) was >10(-4) M and trans (luminal) Ca(2+) concentration was 1.0 mM, but not at low [Ca(2+)](cis). The open probability of single channels increased from zero at 1 x 10(-6) M cis Ca(2+) to 0.73 +/- 0.17 (n = 22) at 10(-3) M cis Ca(2+). Channel openings to the maximum conductance of 38 pS were rapidly and reversibly activated when [Ca(2+)](cis), but not trans Ca(2+) concentration (n = 5), was increased to >5 x 10(-4) M (n = 14). Channel openings to the submaximal conductance of 10.5 pS were dominant at >/=5 x 10(-4) M Ca(2+). K(+) channels did not open when cis Mg(2+) or Sr(2+) concentrations were increased from zero to 10(-3) M or when [Ca(2+)](cis) was maintained at 10(-6) M (n = 3 and 2). The Hill coefficient and the inhibition constant were 1 and 0.8 x 10(-4) M cis Ca(2+), respectively. This dependence of the channel on high [Ca(2+)](cis) suggests that it may become active under 1) physiological conditions where Ca(2+) levels are high, e.g., during cardiac and skeletal muscle contractions, and 2) pathological conditions that lead to a Ca(2+) overload, e.g., ischemic heart and muscle fatigue. The channel could modify a cascade of physiological functions that are dependent on the Ca(2+)-activated K(+) channels, e.g., vasodilation and salt secretion.
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Affiliation(s)
- J I Kourie
- Membrane Transport Group, Department of Chemistry, The Faculties, The Australian National University, Canberra City, Australian Capital Territory 0200, Australia.
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37
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Abstract
The human acetyl-CoA acetyltransferase 2 gene, ACAT2, codes for a thiolase, an enzyme involved in lipid metabolism. The human T-complex protein 1 gene, TCP1, encodes a molecular chaperone of the chaperonin family. The two genes overlap by their 3'-untranslated regions, their coding sequences being located on opposite DNA strands in a tail-to-tail orientation. To find out how the overlap might have arisen in evolution, the homologous genes of the zebrafish, the African toad, caiman, platypus, opossum, and wallaby were identified. In each species, standard or long polymerase chain reactions were used to determine whether the ACAT2 and TCP1 homologs are closely linked and, if so, whether they overlap. The results reveal that the overlap apparently arose during the transition from therapsid reptiles to mammals and has been retained for >200 million years. Part of the overlapping untranslated region shows remarkable sequence conservation. The overlap presumably arose during the chromosomal rearrangement that brought the two unrelated and previously separated genes together. One or both of the transposed genes found by chance signals that are necessary for the processing of their transcripts to be present on the noncoding strand of the partner gene.
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Affiliation(s)
- S Shintani
- Max-Planck-Institut für Biologie, D-72076 Tübingen, Germany
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Toyosawa S, O'hUigin C, Figueroa F, Tichy H, Klein J. Identification and characterization of amelogenin genes in monotremes, reptiles, and amphibians. Proc Natl Acad Sci U S A 1998; 95:13056-61. [PMID: 9789040 PMCID: PMC23708 DOI: 10.1073/pnas.95.22.13056] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two features make the tooth an excellent model in the study of evolutionary innovations: the relative simplicity of its structure and the fact that the major tooth-forming genes have been identified in eutherian mammals. To understand the nature of the innovation at the molecular level, it is necessary to identify the homologs of tooth-forming genes in other vertebrates. As a first step toward this goal, homologs of the eutherian amelogenin gene have been cloned and characterized in selected species of monotremes (platypus and echidna), reptiles (caiman), and amphibians (African clawed toad). Comparisons of the homologs reveal that the amelogenin gene evolves quickly in the repeat region, in which numerous insertions and deletions have obliterated any similarity among the genes, and slowly in other regions. The gene organization, the distribution of hydrophobic and hydrophilic segments in the encoded protein, and several other features have been conserved throughout the evolution of the tetrapod amelogenin gene. Clones corresponding to one locus only were found in caiman, whereas the clawed toad possesses at least two amelogenin-encoding loci.
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Affiliation(s)
- S Toyosawa
- Max-Planck-Institut für Biologie, Abteilung Immungenetik, Corrensstrasse 42, D-72076 Tübingen, Germany
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39
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Munday BL, Whittington RJ, Stewart NJ. Disease conditions and subclinical infections of the platypus (Ornithorhynchus anatinus). Philos Trans R Soc Lond B Biol Sci 1998; 353:1093-9. [PMID: 9720107 PMCID: PMC1692300 DOI: 10.1098/rstb.1998.0268] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Before the arrival of European settlers in Australia, the platypus, Ornithorhynchus anatinus, probably suffered from little disease. Among other things, European settlement has involved substantial environmental perturbation, introduction of large predators, introduction of motor vehicles and translocation of potential pathogens. As a result, platypuses are now killed by motor vehicles, dogs, foxes and discarded plastic litter. Information programmes targeting appropriate segments of the public would help reduce these unnecessary deaths. The enigmatic disease, ulcerative mycosis, caused by Mucor amphibiorum, has been the subject of scientific investigation in Tasmania for the past 15 years. The apparent recent acceleration in its spread has sounded a warning and more intensive investigation is warranted. The possibility that this pathogen has been translocated from subtropical to temperate Tasmania, Australia, with green free frogs in banana shipments further emphasizes the role of humans in threatening the welfare of the platypus. Recommendations are made in relation to appropriate measures that could be taken to ameliorate disease and trauma in this species.
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Affiliation(s)
- B L Munday
- Department of Aquaculture, University of Tasmania, Launceston, Australia
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40
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de Plater GM, Martin RL, Milburn PJ. A C-type natriuretic peptide from the venom of the platypus (Ornithorhynchus anatinus): structure and pharmacology. Comp Biochem Physiol C Pharmacol Toxicol Endocrinol 1998; 120:99-110. [PMID: 9827022 DOI: 10.1016/s0742-8413(98)00030-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A peptide which relaxes rat uterine smooth muscle and exhibits homology with the mammalian C-type natriuretic peptide (CNP) has previously been identified in platypus (Ornithorhynchus anatinus) venom from its partial N-terminal amino acid sequence. In this study we describe the purification, detailed structure, synthesis and pharmacological characteristics of this peptide, which has been designated ovCNP-39 (Ornithorhynchus venom C-type natriuretic peptide). Elucidation of the 39-residue amino acid sequence confirms the homology with mammalian CNPs. These peptides produce hypotension in vivo and relax smooth muscle in vitro, but are poorly characterised in terms of physiological function. ovCNP-39 is equipotent with human/rat/porcine CNP-22 in eliciting cyclic guanosine 5'-monophosphate (cGMP) elevation in cultured vascular smooth muscle cells, suggesting that, like CNP, it acts through the ANPB natriuretic peptide receptor subtype. The direct elevation of cGMP in vascular smooth muscle by ovCNP-39 may underlie the vasodilatory effects of platypus envenomation.
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MESH Headings
- Amino Acid Sequence
- Animals
- Aorta/cytology
- Aorta/drug effects
- Aorta/metabolism
- Cells, Cultured
- Cyclic GMP/metabolism
- Female
- Humans
- In Vitro Techniques
- Molecular Sequence Data
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Natriuretic Peptide, C-Type/chemistry
- Natriuretic Peptide, C-Type/isolation & purification
- Natriuretic Peptide, C-Type/pharmacology
- Peptide Fragments/chemistry
- Peptide Fragments/isolation & purification
- Peptide Fragments/pharmacology
- Platypus
- Rats
- Rats, Wistar
- Sequence Homology, Amino Acid
- Structure-Activity Relationship
- Swine
- Uterine Contraction/drug effects
- Venoms/chemistry
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Affiliation(s)
- G M de Plater
- Centre for Molecular Structure and Function, John Curtin School of Medical Research, Australian National University, Canberra, Australia
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de Plater GM, Martin RL, Milburn PJ. The natriuretic peptide (ovCNP-39) from platypus (Ornithorhynchus anatinus) venom relaxes the isolated rat uterus and promotes oedema and mast cell histamine release. Toxicon 1998; 36:847-57. [PMID: 9663691 DOI: 10.1016/s0041-0101(97)00176-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In this study we characterise the ability of a C-type natriuretic peptide from platypus (Ornithorhynchus anatinus) venom (ovCNP-39) to relax the rat uterus in vitro and we investigate the possibility that ovCNP-39 contributes to the acute effects of envenomation, which include oedema, pain and erythema. We have found that both ovCNP-39 and the endogenous C-type natriuretic peptide, CNP-22, produce oedema in the rat paw and release histamine from rat peritoneal mast cells. Two synthetic peptides, ovCNP-39(1-17) and ovCNP-39(18-39), corresponding to the N- and C-termini, respectively, are equipotent histamine releasers, suggesting that ovCNP-39 and other natriuretic peptides do not act through conventional natriuretic peptide receptors on mast cells.
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Affiliation(s)
- G M de Plater
- The John Curtin School of Medical Research, Australian National University, Canberra ACT
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Abstract
Our present understanding of the origin and evolution of chromosomes differs considerably from current understanding of the origin and evolution of the cell itself. Chromosome origins have been less prominent in research, as the emphasis has not shifted so far appreciably from the phenomenon of primeval nucleic acid encapsulation to that of the origin of gene organization, expression, and regulation. In this work we discuss some reasons why preliminary steps in this direction are being taken. We have been led to examine properties that have contributed to raise the ancestral prokaryotic programmes to a level where we can appreciate in eukaryotes a clear departure from earlier themes in the evolution of the cell from the last common ancestor. We shift our point of view from evolution of cell morphology to the point of view of the genes. In particular, we focus attention on possible physical bases for the way transmission of information has evolved in eukaryotes, namely, the inactivation of whole chromosomes. The special case of the inactivation of the X chromosome in mammals is discussed, paying particular attention to the physical process of the spread of X inactivation in monotremes (platypus and echidna). When experimental data is unavailable some theoretical analysis is possible based on the idea that in certain cases collective phenomena in genetics, rather than chemical detail, are better correlates of complex chemical processes.
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Affiliation(s)
- J Chela-Flores
- International Centre for Theoretical Physics, Trieste, Italy
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Mitchell MJ, Wilcox SA, Watson JM, Lerner JL, Woods DR, Scheffler J, Hearn JP, Bishop CE, Graves JA. The origin and loss of the ubiquitin activating enzyme gene on the mammalian Y chromosome. Hum Mol Genet 1998; 7:429-34. [PMID: 9467000 DOI: 10.1093/hmg/7.3.429] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mammalian sex chromosomes are thought to be descended from a homologous pair of autosomes: a testis-determining allele which defined the Y chromosome arose, recombination between the nascent X and Y chromosomes became restricted and the Y chromosome gradually lost its non-essential genetic functions. This model was originally inferred from the occurrence of few Y-linked genetic traits, pairing of the X and Y chromosomes during male meiosis and, more recently, the existence of X-Y homologous genes. The comparative analysis of such genes is a means by which the validity of this model can be evaluated. One well-studied example of an X-Y homologous gene is the ubiquitin activating enzyme gene ( UBE1 ), which is X-linked with a distinct Y-linked gene in many eutherian ('placental') and metatherian (marsupial) mammals. Nonetheless, no UBE1 homologue has yet been detected on the human Y chromosome. Here we describe a more extensive study of UBE1 homologues in primates and a prototherian mammal, the platypus. Our findings indicate that UBE1 lies within the X-Y pairing segment of the platypus but is absent from the human Y chromosome, having been lost from the Y chromosome during evolution of the primate lineage. Thus UBE1 illustrates the key steps of 'autosomal to X-specific' evolution of genes on the sex chromosomes.
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Affiliation(s)
- M J Mitchell
- INSERM U406, Facult-e de M-edecine La Timone, 13385 Marseille, France.
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Munday BL, Stewart NJ, Södergen A. Occurrence of polychlorinated biphenyls and organochlorine pesticides in platypuses (Ornithorhynchus anatinus) in Tasmania. Aust Vet J 1998; 76:129-30. [PMID: 9578785 DOI: 10.1111/j.1751-0813.1998.tb14546.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- B L Munday
- Department of Aquaculture, University of Tasmania, Launceston, Tasmania
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Philippe H. Rodent monophyly: pitfalls of molecular phylogenies. J Mol Evol 1997; 45:712-5. [PMID: 9419251] [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: 02/05/2023]
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Abstract
1. Australia has some of the most venomous fauna in the world. Although humans are not usually perceived as being predators against these animals they are often envenomated, accidentally or otherwise. This has led to the development of antivenoms against some of the potentially lethal venoms. However, further understanding of the mechanism(s) of action of these and other venoms is important, not only for developing new treatment strategies but also in the search for novel research tools. 2. The present review discusses the pharmacology of some of the components found in venoms and outlines the research undertaken on some of Australia's venomous animals, with the exception of snakes. 3. Biogenic amines, peptides and enzymes are common venom components and produce a wide range of effects in envenomated humans. For example, respiratory failure observed after envenomation by the box jellyfish (Chirnex fleckeri) and Sydney funnel-web spider (Atrax robustus) is most likely due to potent neurotoxins in the venoms. Stonefish (Synanceja trachynis) and platypus (Ornithorhynchus anatinus) venoms, although not considered lethal, cause severe pain. However, the components responsible for these effects have not been isolated. Venom components, as yet unidentified, may be responsible for the cutaneous necrotic lesions that have been reported after some spider bites (e.g. Lampona cylindrata). Other venoms, such as those of the jumper ant (Myrmecia pilosula) and bull ant (M. pyriformis), may produce only mild skin irritation to the majority of humans but a severe anaphylactic response in sensitized victims. 4. While there has been a renewed interest in toxinology, further research is required to fully elucidate the pharmacological action of many of these venoms.
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Affiliation(s)
- W C Hodgson
- Department of Pharmacology, Monash University, Clayton, Victoria, Australia
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Abstract
A very old unanswered question in classical cytology is whether chromosomes are arranged randomly in sperm or whether they occupy specific positions. Even with modern methods of chromosome painting, it is difficult to resolve this question for the very condensed and almost spherical sperm head of most mammals. We have taken advantage of the unusual fibrillar sperm head of monotreme mammals (echidna and platypus) to examine the position of chromosome landmarks in a two-dimensional array. We used fluorescence and radioactive in situ hybridization to telomeric, rDNA, and unique sequences to show that chromosomes are arranged tandemly and in a defined order in the sperm nucleus.
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Affiliation(s)
- J M Watson
- School of Genetics and Human Variation, La Trobe University, Bundoora, Victoria, Australia
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Manger PR, Pettigrew JD. Ultrastructure, number, distribution and innervation of electroreceptors and mechanoreceptors in the bill skin of the platypus, Ornithorhynchus anatinus. Brain Behav Evol 1996; 48:27-54. [PMID: 8828862 DOI: 10.1159/000113185] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The platypus is presently the only mammal demonstrated to use electroreception to obtain food. The electroreceptive system of the platypus is far more complex than that of its close relative the echidna. This paper presents an anatomical study of the basis of electroreception in the platypus. The innervation of the bill by the trigeminal nerve is described, as are three sensory structures, associated with food gathering, within the bill skin. There are 40,000 mucous gland electroreceptors found in the bill skin of the platypus. The papillary portion of each of these sensory mucous glands is modified to accommodate electrosensory nerve terminals. In contrast to fish electroreceptors, the electrosensory terminals of the platypus are not associated with a sensory cell. These mucous gland electroreceptors are arranged in a series of parasagittal stripes on the bill. This array suggests a basis for the ability of the platypus to quickly and accurately locate the origin of an electrical stimulus. A push-rod mechanoreceptor, similar in morphology to Eimer's organ of the mole, and bill-tip organs in birds, was also found in the bill skin. The slightly differing morphology of these mechanoreceptors when compared to their avian and talpid counterparts suggests that this is another example of convergent evolution, with the common need to provide a solution to increasing tactile sensitivity on bare rhinarial skin. These push-rods are found to be most dense around the labial margins of the bill, with a marked decrease in density towards the middle and caudal portions of the bill. The distribution of the push-rods is similar to the distribution of the third sensory structure found on the bill, the sensory serous gland. Although less numerous than the mechanoreceptors (46,500 mechanoreceptors compared with 13,500 sensory serous glands), these sensory serous glands have a similar distribution and similar changes in density. These concurrent distributions argue for some functional correlation of these two sensory structures. The papillary region of the serous gland is modified in a manner similar to that of the mucous gland electroreceptor to accommodate sensory input. The sensory terminals of the serous glands are very similar to those of the mucous gland electroreceptors, and so it is presumed that these sensory serous glands are a type of electroreceptor that might be involved in detection of electrical signals at close quarters where the mechanoreceptors are also engaged.
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Affiliation(s)
- P R Manger
- Department of Physiology and Pharmacology, University of Queensland, St. Lucia, Australia
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Abstract
In this study several activities of the venom of Ornithorhynchus anatinus have been investigated. Whole venom induced local oedema after subplantar injection and produced relaxation of the rat uterus in vitro. The relaxant activity was partially purified by gel permeation HPLC and subsequent analyses by SDS-PAGE revealed that this activity was associated with a 4200 mol. wt peptide. The N-terminal partial sequence of this peptide exhibited substantial identity with human and porcine C-type natriuretic peptide (CNP). Three other major proteins isolated from the venom had mol. wts of 140,000, 55,000 and 16,000. None was found to have any sequence homology with proteins listed in the SwissProt database. The 140,000 mol. wt protein exhibited hyaluronidase activity but the nature of the 55,000 and 16,000 mol. wt proteins remains to be determined. Platypus venom also exhibits protease activity, although the concentration of proteolytic enzymes was too low to be visualised by SDS-PAGE using Coomassie staining.
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Affiliation(s)
- G de Plater
- Division of Botany and Zoology, Australian National University, Canberra
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