| response of nuclear polyhedrosis virus-resistant spodoptera frugiperda larvae to other pathogens and to chemical insecticides. | selection in the laboratory for spodoptera frugiperda (sf) resistant to nuclear polyhedrosis virus (npv) affected the susceptibility of the insect to certain other mortality agents, including a chemical insecticide. median lethal concentrations (lc50s) and associated statistics were compared for several mortality agents between colonies of npv-resistant and -susceptible (control) insects. compared to the susceptible insects, the npv-resistant insects were cross-resistant to the s. frugiperda gra ... | 1990 | 2108223 |
| two-dimensional electrophoretic analysis of spore proteins of the microsporida. | microsporida are potentially useful as biological control agents for insects of economic and medical importance. prior to their responsible use, however, an accurate and reliable means of identification to the species and subspecies level is required. current methods used for identification are not adequate, due to variability of identifiable characters and to the occurrence of dimorphism. recently, progress has been made in the use of biochemical characteristics to support the more traditional ... | 1987 | 3116194 |
| ribosomal rna sequence suggests microsporidia are extremely ancient eukaryotes. | the microsporidia are a group of unusual, obligately parasitic protists that infect a great variety of other eukaryotes, including vertebrates, arthropods, molluscs, annelids, nematodes, cnidaria and even various ciliates, myxosporidia and gregarines. they possess a number of unusual cytological and molecular characteristics. their nuclear division is considered to be primitive, they have no mitochondria, their ribosomes and ribosomal rnas are reported to be of prokaryotic size and their large r ... | 1987 | 3550472 |
| [cloning and phylogenetic analysis of small subunit ribosomal rna core sequence of vairimorpha ceraces (microspora: burenellidae) from the insect of lepidoptera, cerace stipatana (walker)]. | vairimorpha ceraces is a new microsporidium that isolated from the insect of lepidoptera, cerace stipatana (walker). we used 16s rdna sequence to explore genetic status of vairimorpha ceraces. | 2008 | 19149157 |
| unique phylogenetic position of diplomonadida based on the complete small subunit ribosomal rna sequence of giardia ardeae, g. muris, g. duodenalis and hexamita sp. | complete small-subunit rrna (ssu-rrna) coding region sequences were determined for two species of the intestinal parasite giardia: g. ardeae and g. muris, both belonging to the order diplomonadida, and a free-living member of this order, hexamita sp. these sequences were compared to published ssu-rdna sequences from a third member of the genus giardia, g. duodenalis (often called g. intestinalis or g. lamblia) and various representative organisms from other taxa. of the three giardia sequences a ... | 1993 | 8422968 |
| phylogenetic relationships among vairimorpha and nosema species (microspora) based on ribosomal rna sequence data. | a portion (approximately 350 nucleotides) of the large subunit ribosomal rna (rrna) 5' to the 580 region (escherichia coli numbering) was sequenced using the reverse transcriptase dideoxy method and compared for several species of nosema and vairimorpha. comparison among nosema species suggests that this genus is composed of several unrelated groups. the group which includes the type species, nosema bombycis, consists of closely related species found primarily in lepidoptera. other nosema specie ... | 1994 | 7963643 |
| eukaryotic ribosomes that lack a 5.8s rna. | the 5.8s ribosomal rna is believed to be a universal eukaryotic characteristic. it has no (size) counterpart among the prokaryotes, although its sequence is homologous with the first 150 or so nucleotides of the prokaryotic large subunit (23s) ribosomal rna. we report here an exception to this rule. the microsporidian vairimorpha necatrix is a eukaryote that has no 5.8s rrna. as in the prokaryotes, it has a single large subunit rrna, whose 5' region corresponds to the 5.8s rrna. | 1986 | 3083262 |
| a new isolate of the microsporidium vairimorpha necatrix (microsporidia, burenellidae) recorded in the azores. | | 2004 | 14992862 |
| the pathogenicity of vairimorpha necatrix (microspora: microsporidia) against the tomato moth, lacanobia oleracea (lepidoptera: noctuidae) and its potential use for the control of lepidopteran glasshouse pests. | a droplet feeding technique was used to feed known amounts of vairimorpha necatrix (kramer) spores to larvae of the tomato moth, lacanobia oleracea (l) in order to assess the susceptibility of this lepidopteran pest to the pathogen. all first- to fourth-instar larvae died as a result of ingesting 1000 or more v necatrix spores. two forms of death were observed, which were dependent on the dose and the age of the insect when treated. for first-instar larvae, rapid death (within 6days of dosing) o ... | 2004 | 15307667 |
| interactions between the solitary endoparasitoid, meteorus gyrator (hymenoptera: braconidae) and its host, lacanobia oleracea (lepidoptera: noctuidae), infected with the entomopathogenic microsporidium, vairimorpha necatrix (microspora: microsporidia). | infection of lacanobia oleracea (linnaeus) larvae with the microsporidium vairimorpha necatrix (kramer) resulted in significant effects on the survival and development of the braconid parasitoid, meteorus gyrator (thunberg). female m. gyrator did not show any avoidance of v. necatrix-infected hosts when they were selecting hosts for oviposition. when parasitism occurred at the same time as infection by the pathogen, or up to four days later, no significant detrimental effects on the parasitoid w ... | 2005 | 15877862 |
| infection by the microsporidium vairimorpha necatrix (microspora: microsporidia) elevates juvenile hormone titres in larvae of the tomato moth, lacanobia oleracea (lepidoptera: noctuidae). | the effects of infection by a microsporidium, vairimorpha necatrix (kramer), on the endogenous levels of juvenile hormones in tomato moth (lacanobia oleracea l.) larvae were investigated. levels of juvenile hormone ii (jh ii) were 10-fold greater in the infected larvae on day two of the sixth stadium but no significant difference was observed on day seven. juvenile hormone i (jh i) was also detected in day two and day seven sixth instar infected larvae but was not detected in non-infected larvae ... | 2008 | 18048053 |
| morphological and molecular studies of vairimorpha necatrix bm, a new strain of the microsporidium v. necatrix (microsporidia, burenellidae) recorded in the silkworm, bombyx mori. | vairimorpha sp. bm (2012) is a recent isolate of the microsporidia from the silkworm in shandong, china. the ultrastructure, tissue pathology and molecular characterization of this isolate is described in this study. this pathogenic fungus causes pebrine disease in silkworms which manifests as a systemic infection. meanwhile, the silkworm eggs produced by the infected moths were examined using a microscope and pcr amplification. neither spores nor the expected pcr band were observed, suggesting ... | 2014 | 24818618 |
| the storage of infective spores of vairimorpha necatrix (protozoa: microsporida) in antibiotic solution at 4 degrees c. | | 2001 | 98593 |
| protist evolution and phylogeny as discerned from small subunit ribosomal rna sequence comparisons. | ribosomal rna sequence comparisons reveal an evolutionary diversity among unicellular eukaryotes far exceeding that observed within the multicellular or prokaryote kingdoms. the analysis of small subunit ribosomal rnas provides new insights into the evolution and phylogenetic relationships of major lineages. the parasitic diplomonad flagellate giardia lamblia diverges first on the eukaryotic tree, followed by another parasite, the microsporidian vairimorpha necatrix. further, a close relationshi ... | 2011 | 23194754 |
| ultrastructure, chromosomal karyotype, and molecular phylogeny of a new isolate of microsporidian vairimorpha sp. bm (microsporidia, nosematidae) from bombyx mori in china. | the spore morphology, chromosomal karyotype, and molecular systematic of a new microsporidian which was isolated from the domesticated silkworm bombyx mori (lepidoptera: bombycidae) in shandong, china have been studied. the spores were long oval and measured 3.4 × 1.6 μm on fresh smears. ultrastructure of the spores was characteristic for the genus vairimorpha: 13-15 polar filament coils, posterior vacuole, and a diplokaryon. six chromosome bands have been separated by pulsed field gel electroph ... | 2011 | 21633844 |
| phylogenetic relationships of heterovesicula cowani, a microsporidian pathogen of mormon crickets, anabrus simplex (orthoptera: tettigoniidae), based on ssu rdna-sequence analyses. | the microsporidium heterovesicula cowani, discovered in 1985, was initially identified as vairimorpha sp. because it produces two types of spores: nosema-like diplokaryotic spores and thelohania-like mononuclear meiospores. however, light and electron microscopy studies revealed characters that did not fit any known microsporidian genera, and a new monotypic genus heterovesicula was erected. the goal of this study was to test the validity of the genus heterovesicula by molecular characterization ... | 2008 | 18374939 |
| ultrastructural characteristics and small subunit ribosomal dna sequence of vairimorpha cheracis sp. nov., (microspora: burenellidae), a parasite of the australian yabby, cherax destructor (decapoda: parastacidae). | this is the first record of a species of vairimorpha infecting a crustacean host. vairimorpha cheracis sp. nov. was found in a highland population of the australian freshwater crayfish, cherax destructor. the majority of spores and earlier developmental stages of v. cheracis sp. nov. were found within striated muscle cells of the thorax, abdomen, and appendages of the crayfish. only octosporoblastic sporogony within sporophorous vesicles (spvs) was observed. diplokaryotic sporonts separated into ... | 2003 | 14726242 |
| vairimorpha imperfecta n.sp., a microsporidian exhibiting an abortive octosporous sporogony in plutella xylostella l. (lepidoptera: yponomeutidae). | the microsporidian genus nosema is characterized by development in direct control with host cell cytoplasm, diplokaryotic nuclei throughout development and disporous sporogony. the genus vairimorpha exhibits the same features plus an octoporous sporogony producing uninucleate spores in a sporophorous vesicle. a microsporidium from diamondback moth, plutella xylostella, falls between nosema and vairimorpha in that it initiates but fails to complete the octosporous sequence in this host. the name ... | 1999 | 10503253 |
| microsporidian intrasporal sugars and their role in germination. | the hypothesis that spores of terrestrial and aquatic microsporidia differ in their utilization of sugars was tested by evaluating the sugars in germinated and ungerminated spores of several species in each category. the aquatic species tested were vavraia culicis, edhazardia aedis, and nosema algerae and the terrestrial species were vairimorpha necatrix, nosema disstriae, nosema apis, vairimorpha lymantriae, and nosema spp. from spodoptera exigua and plutella xylostella. the percentage germinat ... | 1999 | 10222184 |
| timing of an early sporulation sequence of microsporidia in the genus vairimorpha (microsporidia: burenellidae) | an early sporulation event in the host midgut tissues has been reported for several species of microsporidia infecting diptera, hymenoptera, and lepidoptera. the role of these primary spores, formed between 35 and 96 h postinfection per os, has been suggested to be the cell to cell spread of infection within the host, but the sequence of events during the early sporulation stages has been reported for only a few species of microsporidia. we investigated these early life cycle events for two spec ... | 1998 | 9784358 |
| analysis of the ribosomal dna sequences of the microsporidia thelohania and vairimorpha of fire ants. | sequences of the 16srrna gene of three microsporidia pathogenic to imported fire ants, solenopsis invicta and solenopsis richteri, were determined and compared to each other and 15 other species of microsporidia. the sequences of 2 thelohania species are nearly identical (99.2% identity), supporting light-microscopic and ultrastructural evidence that thelohania solenopsae and thelohania sp. are closely related but probably not conspecific. sequence comparisons further revealed that vairimorpha s ... | 1998 | 9709016 |
| sugar acquisition during the development of microsporidian (microspora: nosematidae) spores | helicoverpa zea larvae were infected with vairimorpha necatrix. the fat body was triturated and sporulation stages were fractionated according to buoyant density by ludox density gradient centrifugation. spores and sporulation stages formed two minor bands with buoyant densities of 1.072 and 1.121 g/ml, and two major bands with buoyant densities of 1.150 and 1.198 g/ml. the higher bands of less dense sporoblastic stages first appeared 96 hr following infection and the band containing the heavies ... | 1997 | 9281397 |
| small subunit ribosomal rna+ of hexamita inflata and the quest for the first branch in the eukaryotic tree. | a phylogenetic analysis of the small subunit ribosomal rna (16s-like rrna) coding region from hexamita inflata demonstrates that parasitism alone cannot explain early diverging eukaryotic lineages. parasitic and free-living diplomonads, as well as trichomonads and microsporidia, diverge at the base of the eukaryotic tree. the relative branching order of diplomonads, trichomonads and microsporidia is influenced by outlying prokaryotic taxa with different g+c compositions in their rrna coding regi ... | 1993 | 8515782 |
| inferring phylogenies from dna sequences of unequal base compositions. | a new method for computing evolutionary distances between dna sequences is proposed. contrasting with classical methods, the underlying model does not assume that sequence base compositions (a, c, g, and t contents) are at equilibrium, thus allowing unequal base compositions among compared sequences. this makes the method more efficient than the usual ones in recovering phylogenetic trees from sequence data when base composition is heterogeneous within the data set, as we show by using both simu ... | 1995 | 7479987 |
| characterization of the highly divergent u2 rna homolog in the microsporidian vairimorpha necatrix. | an rna homologous to u2 rna and a single copy gene encoding the rna homolog have been characterized in the microsporidian, vairimorpha necatrix. the rna which is 165 nucleotides in length possesses significant similarity to u2 rna, particularly in the 5' half of the molecule. the u2 homolog contains the highly conserved guagua branch point binding sequence seen in all u2 rnas except those of the trypanosomes. a u2 rna sequence element implicated in a u2:u6 rna intermolecular pairing is also pres ... | 1996 | 8602366 |
| a mitochondrial hsp70 orthologue in vairimorpha necatrix: molecular evidence that microsporidia once contained mitochondria. | microsporidia are small (1-20 micron) obligate intracellular parasites of a variety of eukaryotes, and they are serious opportunistic pathogens of immunocompromised patients [1]. microsporidia are often assigned to the first branch in gene trees of eukaryotes [2,3], and are reported to lack mitochondria [2,4]. like diplomonads and trichomonads, microsporidia are hypothesised to have diverged from the main eukaryotic stock prior to the event that led to the mitochondrion endosymbiosis [2,4]. they ... | 1997 | 9382838 |
| microsporidia are related to fungi: evidence from the largest subunit of rna polymerase ii and other proteins. | we have determined complete gene sequences encoding the largest subunit of the rna polymerase ii (rbp1) from two microsporidia, vairimorpha necatrix and nosema locustae. phylogenetic analyses of these and other rpb1 sequences strongly support the notion that microsporidia are not early-diverging eukaryotes but instead are specifically related to fungi. our reexamination of elongation factors ef-1alpha and ef-2 sequence data that had previously been taken as support for an early (archezoan) diver ... | 1999 | 9892676 |