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Bai Y, Lei H, Song W, Shin SC, Wang J, Xiao B, Koçer ZA, Song MS, Webster R, Webby RJ, Wong SS, Zanin M. Amino acids in the polymerase complex of shorebird-isolated H1N1 influenza virus impact replication and host-virus interactions in mammalian models. Emerg Microbes Infect 2024; 13:2332652. [PMID: 38517705 PMCID: PMC11018082 DOI: 10.1080/22221751.2024.2332652] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 03/15/2024] [Indexed: 03/24/2024]
Abstract
A diverse population of avian influenza A viruses (AIVs) are maintained in wild birds and ducks yet the zoonotic potential of AIVs in these environmental reservoirs and the host-virus interactions involved in mammalian infection are not well understood. In studies of a group of subtype H1N1 AIVs isolated from migratory wild birds during surveillance in North America, we previously identified eight amino acids in the polymerase genes PB2 and PB1 that were important for the transmissibility of these AIVs in a ferret model of human influenza virus transmission. In this current study we found that PB2 containing amino acids associated with transmissibility at 67, 152, 199, 508, and 649 and PB1 at 298, 642, and 667 were associated with more rapid viral replication kinetics, greater infectivity, more active polymerase complexes and greater kinetics of viral genome replication and transcription. Pathogenicity in the mouse model was also impacted, evident as greater weight loss and lung pathology associated with greater inflammatory lung cytokine expression. Further, these AIVs all contained the avian-type amino acids of PB2-E627, D701, G590, Q591 and T271. Therefore, our study provides novel insights into the role of the AIV polymerase complex in the zoonotic transmission of AIVs in mammals.
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Affiliation(s)
- Yaqin Bai
- HKU-Pasteur Research Pole, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China
- Guangzhou Medical University, Guangzhou, People’s Republic of China
- State Key Laboratory of Respiratory Diseases, Guangzhou, People’s Republic of China
| | - Hui Lei
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China
- Centre for Immunology & Infection, Hong Kong SAR, People's Republic of China
| | - Wenjun Song
- Guangzhou Laboratory, Guangzhou International Bio Island, Guangzhou, People’s Republic of China
| | | | - Jiaqi Wang
- Guangzhou Medical University, Guangzhou, People’s Republic of China
- State Key Laboratory of Respiratory Diseases, Guangzhou, People’s Republic of China
| | - Biying Xiao
- Guangzhou Medical University, Guangzhou, People’s Republic of China
- State Key Laboratory of Respiratory Diseases, Guangzhou, People’s Republic of China
| | - Zeynep A. Koçer
- Emerging Viral Diseases Laboratory, Izmir Biomedicine and Genome Center, Izmir, Türkiye
- Department of Biomedicine and Health Technologies, Izmir International Biomedicine and Genome Institute, Izmir, Türkiye
| | - Min-Suk Song
- Department of Microbiology, Chungbuk National University Medical School, Chungbuk, Korea
| | - Robert Webster
- Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Richard J. Webby
- Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital, Memphis, TN, USA
| | - Sook-San Wong
- HKU-Pasteur Research Pole, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Mark Zanin
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, People's Republic of China
- Centre for Immunology & Infection, Hong Kong SAR, People's Republic of China
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Mercan Y, Atim G, Kayed AE, Azbazdar ME, Kandeil A, Ali MA, Rubrum A, McKenzie P, Webby RJ, Erima B, Wabwire-Mangen F, Ukuli QA, Tugume T, Byarugaba DK, Kayali G, Ducatez MF, Koçer ZA. Molecular Characterization of Closely Related H6N2 Avian Influenza Viruses Isolated from Turkey, Egypt, and Uganda. Viruses 2021; 13:v13040607. [PMID: 33918166 PMCID: PMC8065897 DOI: 10.3390/v13040607] [Citation(s) in RCA: 3] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/28/2021] [Accepted: 03/30/2021] [Indexed: 01/22/2023] Open
Abstract
Genetic analysis of circulating avian influenza viruses (AIVs) in wild birds at different geographical regions during the same period could improve our knowledge about virus transmission dynamics in natural hosts, virus evolution as well as zoonotic potential. Here, we report the genetic and molecular characterization of H6N2 influenza viruses isolated from migratory birds in Turkey, Egypt, and Uganda during 2017–2018. The Egyptian and Turkish isolates were genetically closer to each other than they were to the virus isolated from Uganda. Our results also suggest that multiple reassortment events were involved in the genesis of the isolated viruses. All viruses contained molecular markers previously associated with increased replication and/or pathogenicity in mammals. The results of this study indicate that H6N2 viruses carried by migratory birds on the West Asian/East African and Mediterranean/Black Sea flyways have the potential to transmit to mammals including humans. Additionally, adaptation markers in these viruses indicate the potential risk for poultry, which also increases the possibility of human exposure to these viruses.
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Affiliation(s)
- Yavuz Mercan
- Emerging Viral Diseases Laboratory, Izmir Biomedicine and Genome Center, 35340 Izmir, Turkey; (Y.M.); (M.E.A.)
- Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, 35340 Izmir, Turkey
| | - Gladys Atim
- Makerere University Walter Reed Project, P.O. Box 7062 Kampala, Uganda; (G.A.); (B.E.); (F.W.-M.); (Q.A.U.); (T.T.); (D.K.B.)
| | - Ahmed E. Kayed
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza 12311, Egypt; (A.E.K.); (A.K.); (M.A.A.)
| | - M. Ekin Azbazdar
- Emerging Viral Diseases Laboratory, Izmir Biomedicine and Genome Center, 35340 Izmir, Turkey; (Y.M.); (M.E.A.)
- Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, 35340 Izmir, Turkey
| | - Ahmed Kandeil
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza 12311, Egypt; (A.E.K.); (A.K.); (M.A.A.)
| | - Mohamed A. Ali
- Center of Scientific Excellence for Influenza Viruses, National Research Centre, Giza 12311, Egypt; (A.E.K.); (A.K.); (M.A.A.)
| | - Adam Rubrum
- St Jude Children’s Research Hospital, Memphis, TN 38105, USA; (A.R.); (P.M.); (R.J.W.)
| | - Pamela McKenzie
- St Jude Children’s Research Hospital, Memphis, TN 38105, USA; (A.R.); (P.M.); (R.J.W.)
| | - Richard J. Webby
- St Jude Children’s Research Hospital, Memphis, TN 38105, USA; (A.R.); (P.M.); (R.J.W.)
| | - Bernard Erima
- Makerere University Walter Reed Project, P.O. Box 7062 Kampala, Uganda; (G.A.); (B.E.); (F.W.-M.); (Q.A.U.); (T.T.); (D.K.B.)
| | - Fred Wabwire-Mangen
- Makerere University Walter Reed Project, P.O. Box 7062 Kampala, Uganda; (G.A.); (B.E.); (F.W.-M.); (Q.A.U.); (T.T.); (D.K.B.)
- School of Public Health, Makerere University, P.O. Box 7062 Kampala, Uganda
| | - Qouilazoni A. Ukuli
- Makerere University Walter Reed Project, P.O. Box 7062 Kampala, Uganda; (G.A.); (B.E.); (F.W.-M.); (Q.A.U.); (T.T.); (D.K.B.)
| | - Titus Tugume
- Makerere University Walter Reed Project, P.O. Box 7062 Kampala, Uganda; (G.A.); (B.E.); (F.W.-M.); (Q.A.U.); (T.T.); (D.K.B.)
| | - Denis K. Byarugaba
- Makerere University Walter Reed Project, P.O. Box 7062 Kampala, Uganda; (G.A.); (B.E.); (F.W.-M.); (Q.A.U.); (T.T.); (D.K.B.)
- College of Veterinary Medicine, Makerere University, P.O. Box 7062 Kampala, Uganda
| | - Ghazi Kayali
- Department of Epidemiology, Human Genetics, and Environmental Sciences, University of Texas, Houston, TX 77030, USA;
- Human Link, Dubai, United Arab Emirates
| | | | - Zeynep A. Koçer
- Emerging Viral Diseases Laboratory, Izmir Biomedicine and Genome Center, 35340 Izmir, Turkey; (Y.M.); (M.E.A.)
- Izmir International Biomedicine and Genome Institute, Dokuz Eylul University, 35340 Izmir, Turkey
- Correspondence: ; Tel.: +90-232-299-4165
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Zanin M, Koçer ZA, Poulson RL, Gabbard JD, Howerth EW, Jones CA, Friedman K, Seiler J, Danner A, Kercher L, McBride R, Paulson JC, Wentworth DE, Krauss S, Tompkins SM, Stallknecht DE, Webster RG. Potential for Low-Pathogenic Avian H7 Influenza A Viruses To Replicate and Cause Disease in a Mammalian Model. J Virol 2017; 91:e01934-16. [PMID: 27852855 PMCID: PMC5244340 DOI: 10.1128/jvi.01934-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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: 09/23/2016] [Accepted: 11/10/2016] [Indexed: 11/20/2022] Open
Abstract
H7 subtype influenza A viruses are widely distributed and have been responsible for human infections and numerous outbreaks in poultry with significant impact. Despite this, the disease-causing potential of the precursor low-pathogenic (LP) H7 viruses from the wild bird reservoir has not been investigated. Our objective was to assess the disease-causing potential of 30 LP H7 viruses isolated from wild avian species in the United States and Canada using the DBA/2J mouse model. Without prior mammalian adaptation, the majority of viruses, 27 (90%), caused mortality in mice. Of these, 17 (56.7%) caused 100% mortality and 24 were of pathogenicity similar to that of A/Anhui/1/2013 (H7N9), which is highly pathogenic in mice. Viruses of duck origin were more pathogenic than those of shorebird origin, as 13 of 18 (72.2%) duck origin viruses caused 100% mortality while 4 of 12 (33.3%) shorebird origin viruses caused 100% mortality, despite there being no difference in mean lung viral titers between the groups. Replication beyond the respiratory tract was also evident, particularly in the heart and brain. Of the 16 viruses studied for fecal shedding, 11 were detected in fecal samples. These viruses exhibited a strong preference for avian-type α2,3-linked sialic acids; however, binding to mammalian-type α2,6-linked sialic acids was also detected. These findings indicate that LP avian H7 influenza A viruses are able to infect and cause disease in mammals without prior adaptation and therefore pose a potential public health risk. IMPORTANCE Low-pathogenic (LP) avian H7 influenza A viruses are widely distributed in the avian reservoir and are the precursors of numerous outbreaks of highly pathogenic avian influenza viruses in commercial poultry farms. However, unlike highly pathogenic H7 viruses, the disease-causing potential of LP H7 viruses from the wild bird reservoir has not been investigated. To address this, we studied 30 LP avian H7 viruses isolated from wild avian species in the United States and Canada using the DBA/2J mouse model. Surprisingly, the majority of these viruses, 90%, caused mortality in mice without prior mammalian adaptation, and 56.7% caused 100% mortality. There was also evidence of spread beyond the respiratory tract and fecal shedding. Therefore, the disease-causing potential of LP avian H7 influenza A viruses in mammals may be underestimated, and these viruses therefore pose a potential public health risk.
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Affiliation(s)
- Mark Zanin
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Zeynep A Koçer
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Rebecca L Poulson
- Department of Population Health, University of Georgia, Athens, Georgia, USA
| | - Jon D Gabbard
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Elizabeth W Howerth
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Cheryl A Jones
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - Kimberly Friedman
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Jon Seiler
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Angela Danner
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Lisa Kercher
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Ryan McBride
- Departments of Cell and Molecular Biology and Chemical Physiology, Scripps Research Institute, La Jolla, California, USA
| | - James C Paulson
- Departments of Cell and Molecular Biology and Chemical Physiology, Scripps Research Institute, La Jolla, California, USA
| | | | - Scott Krauss
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Stephen M Tompkins
- Department of Infectious Diseases, University of Georgia, Athens, Georgia, USA
| | - David E Stallknecht
- Department of Population Health, University of Georgia, Athens, Georgia, USA
| | - Robert G Webster
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
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4
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Abstract
Among the influenza A viruses (IAVs) in wild aquatic birds, only H1, H2, and H3 subtypes have caused epidemics in humans. H1N1 viruses of avian origin have also caused 3 of 5 pandemics. To understand the reappearance of H1N1 in the context of pandemic emergence, we investigated whether avian H1N1 IAVs have contributed to the evolution of human, swine, and 2009 pandemic H1N1 IAVs. On the basis of phylogenetic analysis, we concluded that the polymerase gene segments (especially PB2 and PA) circulating in North American avian H1N1 IAVs have been reintroduced to swine multiple times, resulting in different lineages that led to the emergence of the 2009 pandemic H1N1 IAVs. Moreover, the similar topologies of hemagglutinin and nucleoprotein and neuraminidase and matrix gene segments suggest that each surface glycoprotein coevolved with an internal gene segment within the H1N1 subtype. The genotype of avian H1N1 IAVs of Charadriiformes origin isolated in 2009 differs from that of avian H1N1 IAVs of Anseriformes origin. When the antigenic sites in the hemagglutinin of all 31 North American avian H1N1 IAVs were considered, 60%-80% of the amino acids at the antigenic sites were identical to those in 1918 and/or 2009 pandemic H1N1 viruses. Thus, although the pathogenicity of avian H1N1 IAVs could not be inferred from the phylogeny due to the small dataset, the evolutionary process within the H1N1 IAV subtype suggests that the circulation of H1N1 IAVs in wild birds poses a continuous threat for future influenza pandemics in humans.
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Affiliation(s)
- Zeynep A. Koçer
- Department of Infectious Diseases, Division of Virology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Robert Carter
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Gang Wu
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Jinghui Zhang
- Department of Computational Biology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Robert G. Webster
- Department of Infectious Diseases, Division of Virology, St. Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
- * E-mail:
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5
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Koçer ZA, Fan Y, Huether R, Obenauer J, Webby RJ, Zhang J, Webster RG, Wu G. Survival analysis of infected mice reveals pathogenic variations in the genome of avian H1N1 viruses. Sci Rep 2014; 4:7455. [PMID: 25503687 PMCID: PMC4264002 DOI: 10.1038/srep07455] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 11/24/2014] [Indexed: 11/09/2022] Open
Abstract
Most influenza pandemics have been caused by H1N1 viruses of purely or partially avian origin. Here, using Cox proportional hazard model, we attempt to identify the genetic variations in the whole genome of wild-type North American avian H1N1 influenza A viruses that are associated with their virulence in mice by residue variations, host origins of virus (Anseriformes-ducks or Charadriiformes-shorebirds), and host-residue interactions. In addition, through structural modeling, we predicted that several polymorphic sites associated with pathogenicity were located in structurally important sites, especially in the polymerase complex and NS genes. Our study introduces a new approach to identify pathogenic variations in wild-type viruses circulating in the natural reservoirs and ultimately to understand their infectious risks to humans as part of risk assessment efforts towards the emergence of future pandemic strains.
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Affiliation(s)
- Zeynep A Koçer
- Department of Infectious Diseases, Division of Virology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38105, United States
| | - Yiping Fan
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38105, United States
| | - Robert Huether
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38105, United States
| | - John Obenauer
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38105, United States
| | - Richard J Webby
- Department of Infectious Diseases, Division of Virology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38105, United States
| | - Jinghui Zhang
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38105, United States
| | - Robert G Webster
- Department of Infectious Diseases, Division of Virology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38105, United States
| | - Gang Wu
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38105, United States
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Jones JC, Sonnberg S, Koçer ZA, Shanmuganatham K, Seiler P, Shu Y, Zhu H, Guan Y, Peiris M, Webby RJ, Webster RG. Possible role of songbirds and parakeets in transmission of influenza A(H7N9) virus to humans. Emerg Infect Dis 2014; 20:380-5. [PMID: 24572739 PMCID: PMC3944875 DOI: 10.3201/eid2003.131271] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Avian-origin influenza A(H7N9) recently emerged in China, causing severe human disease. Several subtype H7N9 isolates contain influenza genes previously identified in viruses from finch-like birds. Because wild and domestic songbirds interact with humans and poultry, we investigated the susceptibility and transmissibility of subtype H7N9 in these species. Finches, sparrows, and parakeets supported replication of a human subtype H7N9 isolate, shed high titers through the oropharyngeal route, and showed few disease signs. Virus was shed into water troughs, and several contact animals seroconverted, although they shed little virus. Our study demonstrates that a human isolate can replicate in and be shed by such songbirds and parakeets into their environment. This finding has implications for these birds' potential as intermediate hosts with the ability to facilitate transmission and dissemination of A(H7N9) virus.
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Shtarkman YM, Koçer ZA, Edgar R, Veerapaneni RS, D’Elia T, Morris PF, Rogers SO. Subglacial Lake Vostok (Antarctica) accretion ice contains a diverse set of sequences from aquatic, marine and sediment-inhabiting bacteria and eukarya. PLoS One 2013; 8:e67221. [PMID: 23843994 PMCID: PMC3700977 DOI: 10.1371/journal.pone.0067221] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 05/20/2013] [Indexed: 11/21/2022] Open
Abstract
Lake Vostok, the 7th largest (by volume) and 4th deepest lake on Earth, is covered by more than 3,700 m of ice, making it the largest subglacial lake known. The combination of cold, heat (from possible hydrothermal activity), pressure (from the overriding glacier), limited nutrients and complete darkness presents extreme challenges to life. Here, we report metagenomic/metatranscriptomic sequence analyses from four accretion ice sections from the Vostok 5G ice core. Two sections accreted in the vicinity of an embayment on the southwestern end of the lake, and the other two represented part of the southern main basin. We obtained 3,507 unique gene sequences from concentrates of 500 ml of 0.22 µm-filtered accretion ice meltwater. Taxonomic classifications (to genus and/or species) were possible for 1,623 of the sequences. Species determinations in combination with mRNA gene sequence results allowed deduction of the metabolic pathways represented in the accretion ice and, by extension, in the lake. Approximately 94% of the sequences were from Bacteria and 6% were from Eukarya. Only two sequences were from Archaea. In general, the taxa were similar to organisms previously described from lakes, brackish water, marine environments, soil, glaciers, ice, lake sediments, deep-sea sediments, deep-sea thermal vents, animals and plants. Sequences from aerobic, anaerobic, psychrophilic, thermophilic, halophilic, alkaliphilic, acidophilic, desiccation-resistant, autotrophic and heterotrophic organisms were present, including a number from multicellular eukaryotes.
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Affiliation(s)
- Yury M. Shtarkman
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, United States of America
| | - Zeynep A. Koçer
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, United States of America
| | - Robyn Edgar
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, United States of America
| | - Ram S. Veerapaneni
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, United States of America
| | - Tom D’Elia
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, United States of America
| | - Paul F. Morris
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, United States of America
| | - Scott O. Rogers
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, United States of America
- * E-mail:
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D'souza NA, Kawarasaki Y, Gantz JD, Lee RE, Beall BFN, Shtarkman YM, Koçer ZA, Rogers SO, Wildschutte H, Bullerjahn GS, McKay RML. Diatom assemblages promote ice formation in large lakes. ISME J 2013; 7:1632-40. [PMID: 23552624 DOI: 10.1038/ismej.2013.49] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 02/12/2013] [Accepted: 02/16/2013] [Indexed: 11/09/2022]
Abstract
We present evidence for the directed formation of ice by planktonic communities dominated by filamentous diatoms sampled from the ice-covered Laurentian Great Lakes. We hypothesize that ice formation promotes attachment of these non-motile phytoplankton to overlying ice, thereby maintaining a favorable position for the diatoms in the photic zone. However, it is unclear whether the diatoms themselves are responsible for ice nucleation. Scanning electron microscopy revealed associations of bacterial epiphytes with the dominant diatoms of the phytoplankton assemblage, and bacteria isolated from the phytoplankton showed elevated temperatures of crystallization (T(c)) as high as -3 °C. Ice nucleation-active bacteria were identified as belonging to the genus Pseudomonas, but we could not demonstrate that they were sufficiently abundant to incite the observed freezing. Regardless of the source of ice nucleation activity, the resulting production of frazil ice may provide a means for the diatoms to be recruited to the overlying lake ice, thereby increasing their fitness. Bacterial epiphytes are likewise expected to benefit from their association with the diatoms as recipients of organic carbon excreted by their hosts. This novel mechanism illuminates a previously undescribed stage of the life cycle of the meroplanktonic diatoms that bloom in Lake Erie and other Great Lakes during winter and offers a model relevant to aquatic ecosystems having seasonal ice cover around the world.
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Affiliation(s)
- N A D'souza
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA
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9
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Rogers SO, Shtarkman YM, Koçer ZA, Edgar R, Veerapaneni R, D'Elia T. Ecology of subglacial lake vostok (antarctica), based on metagenomic/metatranscriptomic analyses of accretion ice. Biology (Basel) 2013; 2:629-50. [PMID: 24832801 PMCID: PMC3960894 DOI: 10.3390/biology2020629] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/25/2013] [Accepted: 03/19/2013] [Indexed: 11/16/2022]
Abstract
Lake Vostok is the largest of the nearly 400 subglacial Antarctic lakes and has been continuously buried by glacial ice for 15 million years. Extreme cold, heat (from possible hydrothermal activity), pressure (from the overriding glacier) and dissolved oxygen (delivered by melting meteoric ice), in addition to limited nutrients and complete darkness, combine to produce one of the most extreme environments on Earth. Metagenomic/metatranscriptomic analyses of ice that accreted over a shallow embayment and over the southern main lake basin indicate the presence of thousands of species of organisms (94% Bacteria, 6% Eukarya, and two Archaea). The predominant bacterial sequences were closest to those from species of Firmicutes, Proteobacteria and Actinobacteria, while the predominant eukaryotic sequences were most similar to those from species of ascomycetous and basidiomycetous Fungi. Based on the sequence data, the lake appears to contain a mixture of autotrophs and heterotrophs capable of performing nitrogen fixation, nitrogen cycling, carbon fixation and nutrient recycling. Sequences closest to those of psychrophiles and thermophiles indicate a cold lake with possible hydrothermal activity. Sequences most similar to those from marine and aquatic species suggest the presence of marine and freshwater regions.
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Affiliation(s)
- Scott O Rogers
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
| | - Yury M Shtarkman
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
| | - Zeynep A Koçer
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
| | - Robyn Edgar
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
| | - Ram Veerapaneni
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
| | - Tom D'Elia
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
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Koçer ZA, Krauss S, Stallknecht DE, Rehg JE, Webster RG. The potential of avian H1N1 influenza A viruses to replicate and cause disease in mammalian models. PLoS One 2012; 7:e41609. [PMID: 22848544 PMCID: PMC3404991 DOI: 10.1371/journal.pone.0041609] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 06/22/2012] [Indexed: 01/21/2023] Open
Abstract
H1N1 viruses in which all gene segments are of avian origin are the most frequent cause of influenza pandemics in humans; therefore, we examined the disease-causing potential of 31 avian H1N1 isolates of American lineage in DBA/2J mice. Thirty of 31 isolates were very virulent, causing respiratory tract infection; 22 of 31 resulted in fecal shedding; and 10 of 31 were as pathogenic as the pandemic 2009 H1N1 viruses. Preliminary studies in BALB/cJ mice and ferrets showed that 1 of 4 isolates tested was more pathogenic than the pandemic 2009 H1N1 viruses in BALB/cJ mice, and 1 of 2 strains transmitted both by direct and respiratory-droplet contact in ferrets. Preliminary studies of other avian subtypes (H2, H3, H4, H6, H10, H12) in DBA/2J mice showed lower pathogenicity than the avian H1N1 viruses. These findings suggest that avian H1N1 influenza viruses are unique among influenza A viruses in their potential to infect mammals.
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Affiliation(s)
- Zeynep A. Koçer
- Department of Infectious Diseases, Division of Virology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Scott Krauss
- Department of Infectious Diseases, Division of Virology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - David E. Stallknecht
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Jerold E. Rehg
- Department of Pathology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
| | - Robert G. Webster
- Department of Infectious Diseases, Division of Virology, St Jude Children’s Research Hospital, Memphis, Tennessee, United States of America
- * E-mail:
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