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Kneallhazia carolinensae sp. nov., a microsporidian pathogen of the thief ant, Solenopsis carolinensis. J Invertebr Pathol 2011; 108:59-62. [DOI: 10.1016/j.jip.2011.06.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 06/24/2011] [Accepted: 06/27/2011] [Indexed: 11/23/2022]
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Biology and life-cycle of the microsporidium Kneallhazia solenopsae Knell Allan Hazard 1977 gen. n., comb. n., from the fire ant Solenopsis invicta. Parasitology 2008; 135:903-29. [DOI: 10.1017/s003118200800440x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYThelohania solenopsae is a unique microsporidium with a life-cycle finely tuned to parasitizing fire ant colonies. Unlike other microsporidia of social hymenopterans, T. solenopsae infects all castes and stages of the host. Four distinctive spore types are produced: diplokaryotic spores, which develop only in brood (Type 1 DK spores); octets of octospores within sporophorous vesicles, the most prominent spore type in adults but never occurring in brood; Nosema-like diplokaryotic spores (Type 2 DK spores) developing in adults; and megaspores, which occur occasionally in larvae 4, pupae, and adults of all castes but predominantly infect gonads of alates and germinate in inseminated ovaries of queens. Type 2 DK spores function in autoinfection of adipocytes. Proliferation of diplokaryotic meronts in some cells is followed by karyogamy of diplokarya counterparts and meiosis, thereby switching the diplokaryotic sequence to octospore or megaspore development. Megaspores transmit the pathogen transovarially. From the egg to larvae 4, infection is inapparent and can be detected only by PCR. Type 1 DK spore and megaspore sequences are abruptly triggered in larvae 4, the key stage in intra-colony food distribution via trophallaxis, and presumably the central player in horizontal transmission of spores. Molecular, morphological, ultrastructural and life-cycle data indicate that T. solenopsae must be assigned to a new genus. We propose a new combination, Kneallhazia solenopsae.
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Ironside JE. Multiple losses of sex within a single genus of Microsporidia. BMC Evol Biol 2007; 7:48. [PMID: 17394631 PMCID: PMC1853083 DOI: 10.1186/1471-2148-7-48] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Accepted: 03/29/2007] [Indexed: 11/22/2022] Open
Abstract
Background Most asexual eukaryotic lineages have arisen recently from sexual ancestors and contain few ecologically distinct species, providing evidence for long-term advantages of sex. Ancient asexual lineages provide rare exceptions to this rule and so can yield valuable information relating to the evolutionary forces underlying the maintenance of sex. Microsporidia are parasitic, unicellular fungi. They include many asexual species which have traditionally been grouped together into large, presumably ancient taxonomic groups. However, these putative ancient asexual lineages have been identified on the basis of morphology, life cycles and small subunit ribosomal RNA (16S rRNA) gene sequences, all of which hold questionable value in accurately inferring phylogenetic relationships among microsporidia. Results The hypothesis of a single, ancient loss of sex within the Nosema/Vairimorpha group of microsporidia was tested using phylogenetic analyses based on alignments of rRNA and RPB1 gene sequences from sexual and asexual species. Neither set of gene trees supported ancient asexuality, instead indicating at least two, recent losses of sex. Conclusion Sex has been lost on multiple, independent occasions within the Nosema/Vairimorpha group of microsporidia and there is no evidence for ancient asexual lineages. It appears therefore that sex confers important long-term advantages even upon highly simplified eukaryotes such as microsporidia. The rapid evolution of microsporidian life cycles indicated by this study also suggests that even closely related microsporidia cannot be assumed to have similar life cycles and the life cycle of each newly discovered species must therefore be completely described. These findings are relevant to the use of microsporidia as biological control agents, since several species under consideration as potential agents have life cycles that have been incompletely described.
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MESH Headings
- Bayes Theorem
- Consensus Sequence
- Genes, Fungal
- Genes, rRNA
- Microsporidia/genetics
- Microsporidia/growth & development
- Models, Genetic
- Phylogeny
- RNA, Fungal/genetics
- RNA, Ribosomal
- RNA, Ribosomal, 16S/genetics
- RNA, Ribosomal, 18S/genetics
- Reproduction, Asexual
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Affiliation(s)
- Joseph E Ironside
- Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion, UK.
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Preston CA, Fritz GN, Vander Meer RK. Prevalence of Thelohania solenopsae infected Solenopsis invicta newly mated queens within areas of differing social form distributions. J Invertebr Pathol 2007; 94:119-24. [PMID: 17112537 DOI: 10.1016/j.jip.2006.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 09/25/2006] [Accepted: 09/29/2006] [Indexed: 11/21/2022]
Abstract
Newly mated queens (NMQs) originating from monogyne red imported fire ant (Solenopsis invicta) colonies and following a mating flight, initiate new colonies by sealing themselves in a nuptial chamber and relying solely on their own fat and crop reserves, as well as no longer needed wing muscles to rear their first workers (claustral colony foundation). This method of colony-founding is rarely successful for polygyne-derived NMQs, whose low weight critically limits the number of first workers they are able to produce. However, this observation may be confounded by the parasitic microsporidium, Thelohania solenopsae, thus far found to persist only in association with polygyne colonies. Infections of this microsporidium reduce the weight of female alates and may explain why polygyne NMQs are unlikely to successfully found colonies claustrally. NMQs collected following mating flights in Gainesville and Ocala, Florida were sorted by weight, checked for insemination and T. solenopsae infection. Insemination levels were greater than 90% for all weight classes at both collection sites and were not related to infection. Infection levels were lower in Gainesville than Ocala, averaging 1.67% and 14.14%, respectively. Polygyne-derived NMQs collected in Ocala, defined here as weighing 12mg (social form correctly assigned in 85% of samples examined by PCR), had the highest infection levels, 25.37% (17/67) in 2003 and 21.43% (6/28) in 2004. We conclude that infection by T. solenopsae cannot be completely responsible for the inability of polygyne NMQs to claustrally establish colonies.
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Affiliation(s)
- C A Preston
- Center for Medical, Agricultural, and Veterinary Entomology, U.S., Department of Agriculture, Agricultural Research Service, 1600 SW 23rd Drive, Gainesville, FL 32608, USA
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Oi DH. Effect of mono- and polygyne social forms on transmission and spread of a microsporidium in fire ant populations. J Invertebr Pathol 2006; 92:146-51. [PMID: 16764885 DOI: 10.1016/j.jip.2006.04.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2006] [Accepted: 03/12/2006] [Indexed: 11/22/2022]
Abstract
Thelohania solenopsae is a pathogen of the red imported fire ant, Solenopsis invicta, which debilitates queens and eventually causes the demise of colonies. Reductions of infected field populations signify its potential usefulness as a biological control agent. Thelohania solenopsae can be transmitted by introducing infected brood into a colony. The social forms of the fire ant, that is, monogyny (single queen per colony) or polygyny (multiple queens per colony), are associated with different behaviors, such as territoriality, that affect the degree of intercolony brood transfer. T. solenopsae was found exclusively in polygyne colonies in Florida. Non-synchronous infections of queens and transovarial transmission favor the persistence and probability of detecting infections in polygynous colonies. However, queens or alates with the monogyne genotype can be infected, and infections in monogyne field colonies have been reported from Louisiana and Argentina. Limited independent colony-founding capability and shorter dispersal of alate queens with the polygyne genotype relative to monogyne alates may facilitate the maintenance of infections in local polygynous populations. Demise of infected monogyne colonies can be twice as fast as in polygyne colonies and favors the pathogen's persistence in polygyne fire ant populations. The social form of the fire ant reflects different physiological and behavioral aspects of the queen and colony that will impact T. solenopsae spread and ultimate usefulness for biological control.
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Affiliation(s)
- David H Oi
- USDA-ARS Center for Medical, Agricultural, and Veterinary Entomology, 1600 SW 23rd Drive, Gainesville, FL 32608, USA.
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Sokolova YY, Fuxa JR, Borkhsenious ON. The nature of Thelohania solenopsae (Microsporidia) cysts in abdomens of red imported fire ants, Solenopsis invicta. J Invertebr Pathol 2006; 90:24-31. [PMID: 15894329 DOI: 10.1016/j.jip.2005.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 03/18/2005] [Accepted: 03/30/2005] [Indexed: 11/29/2022]
Abstract
Sixty four percent of Solenopsis invicta workers infected with Thelohania solenopsis contained 1-6 "cysts" ranging from 70 to 260 microm in diameter. Light and electron microscope analyses showed that cysts are hypertrophied adipocytes transformed by the parasites, each cyst presumably forming from a single cell. In the first step of the pathogenesis, Nosema-like spores functioning in autoinfection are produced; a diplokaryotic sequence leading to their formation causes fat body hypertrophy. When meiosis occurs, it switches parasite development to production of octospores and/or megaspores. Adipocytes become 2-4xlarger than normal in conjunction with intensive parasite multiplication and octospore maturation. Infected cells eventually lose their cellular organization and are converted into reservoirs for spores. There were no manifestations of cellular immunity, such as encapsulation or nodule formation. Similarly, there were no signs of specialized host-parasite interaction that might be interpreted as xenoma-like complexes. The role of the cysts in the parasite's life cycle is unclear. They may represent a defensive reaction of the host sacrificing the infected cells to segregate the infection. Alternatively, the cyst may help protect spores from environmental hazards and provide a concentrated infectious dose to aid horizontal transmission of the microsporidium. We propose to refer to hypertrophied adipocytes filled with T. solenospsae spores as "sporocytosacs", not "cysts."
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Affiliation(s)
- Y Y Sokolova
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA 70803, USA.
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Sokolova YY, McNally LR, Fuxa JR, Vinson SB. Spore morphotypes of Thelohania solenopsae (microsporidia) described microscopically and confirmed by PCR of individual spores microdissected from smears by position ablative laser microbeam microscopy. Microbiology (Reading) 2004; 150:1261-1270. [PMID: 15133089 DOI: 10.1099/mic.0.26838-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Development of Thelohania solenopsae, a parasite of the red imported fire ant (Solenopsis invicta), until recently was thought to include formation of two types of spores: unicellular meiospores, maturing inside sporophorous vesicles in sets of eight (octospores); and Nosema-like binuclear free spores. Megaspores, discovered in 2001, develop primarily in alates and are morphologically distinct from the two previously known types of spores. The role of megaspores in the T. solenopsae life cycle, as well as their existence, has been questioned. The current research includes light and electron microscopic descriptions of the three major spore morphotypes characteristic of T. solenopsae development. In addition, individual octospores and megaspores were isolated into groups of 8–20 from methanol-fixed and Calcofluor-stained smears of the infected ants for subsequent PCR analysis by the laser pressure catapulting function of a position ablative laser microbeam microscope, a technique applied for the first time to research of microsporidia. The PCR-amplified SSU rDNA nucleotide sequences from octospores and megaspores were identical. This, along with the consistency with which megaspores are detected in infected ants, demonstrates that megaspores are integral to the life cycle of T. solenopsae.
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Affiliation(s)
- Yuliya Y Sokolova
- Institute of Cytology, Russian Academy of Sciences, 194064, St Petersburg, Russia
- Department of Entomology, Louisiana Agricultural Experimental Station, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA
| | - Lacey R McNally
- Department of Pathobiological Science, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70805, USA
| | - James R Fuxa
- Department of Entomology, Louisiana Agricultural Experimental Station, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA
| | - S Bradleigh Vinson
- Department of Entomology, Texas A&M University, College Station, TX 77843, USA
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Milks ML, Sokolova YY, Isakova IA, Fuxa JR, Mitchell F, Snowden KF, Vinson SB. Comparative Effectiveness of Light-Microscopic Techniques and PCR in Detecting Thelohania solenopsae (Microsporidia) Infections in Red Imported Fire Ants (Solenopsis invicta). J Eukaryot Microbiol 2004; 51:187-91. [PMID: 15134254 DOI: 10.1111/j.1550-7408.2004.tb00544.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The main goal of this study was to compare the effectiveness of three staining techniques (calcofluor white M2R, Giemsa and modified trichrome), and the polymerase chain reaction (PCR) in detecting the microsporidium Thelohania solenopsae in red imported fire ants (Solenopsis invicta). The effect of the number of ants in a sample on the sensitivity of the staining techniques and the PCR, and the effect of three DNA extraction protocols on the sensitivity of PCR were also examined. In the first protocol, the ants were macerated and the crude homogenate was used immediately in the PCR. In the second protocol, the homogenate was placed on a special membrane (FTA card) that traps DNA, which is subsequently used in the PCR. In the third protocol, the DNA was purified from the homogenate by traditional phenol-chloroform extraction. Except for PCR using FTA cards, the sensitivity (number of samples positive for T. solenopsae) of all detection techniques increased with the number of ants in the sample. Overall, Giemsa was the least sensitive of all detection techniques. Calcofluor was more sensitive than modified trichrome with ants from one site and was equally as sensitive as PCR with crude DNA or a FTA card with ants from both sites. Trichrome staining was equally as sensitive as PCR with a FTA card at both sites, but it was less sensitive than PCR with crude DNA at one site. PCR on FTA cards was less sensitive than PCR with crude DNA for ants from one site but not the other. There was no difference whether crude or phenol-chloroform purified DNA was used as template. In summary, the results of this study show that PCR based on a crude DNA solution is equal to or more sensitive in detecting T. solenopsae than the other detection techniques investigated, and that it can be used as a reliable diagnostic tool for screening field samples of S. invicta for T. solenopsae. Nevertheless, ant smear stained with calcofluor or modified trichrome should be used to buttress findings from PCR.
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Affiliation(s)
- Maynard L Milks
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, USA
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Sokolova YY, McNally LR, Fuxa JR. PCR-based analysis of spores isolated from smears by laser pressure catapult microdissection confirms genetic identity of spore morphotypes of the microsporidian Thelohania solenopsae. J Eukaryot Microbiol 2004; 50 Suppl:584-5. [PMID: 14736173 DOI: 10.1111/j.1550-7408.2003.tb00640.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuliya Y Sokolova
- Department of Entomology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, USA
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Shapiro AM, Becnel JJ, Oi DH, Williams DF. Ultrastructural characterization and further transmission studies of Thelohania solenopsae from Solenopsis invicta pupae. J Invertebr Pathol 2003; 83:177-80. [PMID: 12788287 DOI: 10.1016/s0022-2011(03)00057-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Alexandra M Shapiro
- Center for Medical, Agricultural and Veterinary Entomology, USDA/ARS, P.O. Box 14565, Gainesville, FL 32604, USA.
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