Mitovirus and Mitochondrial Coding Sequences from Basal Fungus Entomophthora muscae.

Fungi constituting the Entomophthora muscae species complex (members of subphylum Entomophthoromycotina, phylum Zoopagamycota) commonly kill their insect hosts and manipulate host behaviors in the process. In this study, we made use of public transcriptome data to identify and characterize eight new species of mitoviruses associated with several different E. muscae isolates. Mitoviruses are simple RNA viruses that replicate in host mitochondria and are frequently found in more phylogenetically apical fungi (members of subphylum Glomeromyoctina, phylum Mucoromycota, phylum Basidiomycota and phylum Ascomycota) as well as in plants. E. muscae is the first fungus from phylum Zoopagomycota, and thereby the most phylogenetically basal fungus, found to harbor mitoviruses to date. Multiple UGA (Trp) codons are found not only in each of the new mitovirus sequences from E. muscae but also in mitochondrial core-gene coding sequences newly assembled from E. muscae transcriptome data, suggesting that UGA (Trp) is not a rarely used codon in the mitochondria of this fungus. The presence of mitoviruses in these basal fungi has possible implications for the evolution of these viruses.

Differential divergences of obligately insect-pathogenic Entomophthora species from fly and aphid hosts.

Three DNA regions (ITS 1, LSU rRNA and GPD) of isolates from the insect-pathogenic fungus genus Entomophthora originating from different fly (Diptera) and aphid (Hemiptera) host taxa were sequenced. The results documented a large genetic diversity among the fly-pathogenic Entomophthora and only minor differences among aphid-pathogenic Entomophthora. The evolutionary time of divergence of the fly and the aphid host taxa included cannot account for this difference. The host-driven divergence of Entomophthora, therefore, has been much greater in flies than in aphids. Host-range differences or a recent host shift to aphid are possible explanations.

Value of host range, morphological, and genetic characteristics within the Entomophthora muscae species complex.

Entomopthora muscae sensu lato is a complex of morphologically similar fungal species pathogenic to evolutionarily advanced flies (Cyclorrhapha). To reach an operational species definition and recognition of species within this complex, the values of host range, morphological and genetic characteristics are reconsidered. Within the E. muscae species complex morphological and nuclear characteristics of the primary conidia are taxonomically important. In this study we compared the dimensions and nuclear numbers of the primary conidia of isolates from their original (natural) hosts and after being transferred to alternative hosts (cross-transmission) in order to check the stability of these characteristics. The conidial characteristics change substantially when produced in alternative host species, but their overall range in variability still fit within the traditional morphological species circumscriptions. The phylogenetic analyses of the ITS II and LSU rRNA gene sequences, revealed three distinct lineages within the complex: E. schizophorae, E. muscae and E. syrphi. Within each of these lineages sequence divergence was seen between isolates originating from different host species. Our studies on the physiological host range showed that several isolates were able to infect alternative dipteran species. Musca domestica was a particularly good receptor. The ecological host range of any individual isolate seems, however, to be limited to one host species evidenced by the occurrence of distinct genotypes within each natural infected host species shown by RAPD. The high host specificity of these fungi emphasizes the importance of identifying the host taxon at species level in the recognition of Entomophthora species. We recommend that morphological characteristics of fungal structures and host taxon, together with molecular data, serve as criteria for species determination in future studies on members of the E. muscae complex.

Intraspecific variation and host specificity of Entomophthora muscae sensu stricto isolates revealed by random amplified polymorphic DNA, universal primed PCR, PCR-restriction fragment length polymorphism, and conidial morphology.

The intraspecific variations of Entomophthora muscae s. str. associated with particular host species, Musca domestica and Delia radicum, sampled from different localities and different years in Denmark and the variation of E. muscae s. str. originating from different host taxa were investigated. The isolates were compared both by primary spore morphology and by three molecular methods: random amplified polymorphic DNA, universal primed PCR, and PCR-restriction fragment length polymorphism. Analyses of the different molecular data showed the same overall picture and separated E. muscae s. str. into two main groups with all the M. domestica isolates in one group and isolates from D. radicum, Coenosia tigrina, and Pegoplata infirma in the second group. E. muscae s. str. isolates from M. domestica also differ significantly from the rest of the E. muscae s. str. isolates with regard to the morphology of the primary conidia, which were bigger and contained significantly more nuclei per conidium. Several different E. muscae s. str. genotypes were documented and each type was restricted to a single host species, indicating a very high degree of host specificity at or below the level of the subfamily.

Isolation and in vitro cultivation of the aphid pathogenic fungus Entomophthora planchoniana.

Entomophthora planchoniana is an important fungal pathogen of aphids. Although Entomophthora chromaphidis has been considered a synonym for E. planchoniana, the two species are now separated, and E. planchoniana is reported not to grow in vitro. In this paper, we describe for the first time the isolation and cultivation of this species. Entomophthora planchoniana was isolated from a population of Ovatus crataegarius (Homoptera, Aphididae), which was infected by E. planchoniana only. The isolates did not sporulate, but the sequence of the small subunit rDNA and the restriction fragment length polymorphism patterns of the first part of the large subunit rDNA and the ITS II region confirm that the isolates were E. planchoniana. The isolated fungus grew in a medium consisting of Grace's insect cell culture medium supplemented with lactalbumin hydrolysate, yeastolate, and 10% fetal bovine serum or in GLEN medium with 10% fetal bovine serum. Vegetative cells of E. planchoniana were long and club-shaped and did not stain with Calcofluor, thus suggesting that they were protoplasts.

Mycosis of bandedwinged whitefly (Trialeurodes abutilonea) (Homoptera: aleyrodidae) caused by Orthomyces aleyrodis gen. & sp. nov. (Entomophthorales: Entomophthoraceae).

A new genus and species of fungus, Orthomyces aleyrodis Steinkraus, Humber & Oliver gen. & sp. nov. (Entomophthorales: Entomophthoraceae) is described. In 1994 and 1995, this fungus caused epizootics in high populations of bandedwinged whitefly (Trialeurodes abutilonea) on cotton and cocklebur in Alabama. In 1996, T. abutilonea populations were lower and no infected specimens were found. This is the first report of an entomophthoralean infecting an aleyrodid in the New World and the first report of entomophthoralean epizootics in whiteflies.

Immunological separation of Entomophthorales genera.

Exoantigens from Erynia neoaphidis, Conidiobolus major, C. thromboides, C. obscurus, Zoophthora radicans, and Basidiobolus ranarum were obtained from culture filtrates of fungal material grown in a yeast extract, peptone dialysate, dextrose medium and were tested against specific hyperimmune antisera prepared from E. neoaphidis, C. major, C. thromboides, and B. ranarum by the immunodiffusion technique. Specific precipitins were observed for E. neoaphidis and B. ranarum, while cross-reactions were detected among C. major, C. thromboides, and C. obscurus. The results suggest that genera of Entomophthorales can be easily separated by this simple immunological procedure.

Blastocystis hominis: evidence for human pathogenicity and effectiveness of metronidazole therapy.

1. Clinical symptoms and oral treatment with metronidazole were studied in 103 patients with pure infections by Blastocystis hominis. 2. The results showed that excessive flatulence is the chief gastrointestinal symptom associated occasionally with diarrhoea and abdominal cramps. All the patients showed good responses with treatment of metronidazole and 74 patients whose stools were reexamined 1-2 months after the treatment demonstrated no signs of infections. 3. It is concluded that B. hominis is a pathogenic intestinal parasite and the infection could be eradicated successfully by oral metronidazole.

[Nutritional requirements of Entomophthorales (author's transl)]. / Comparison des exigences nutritionnelles de Entomophthorales.

Twenty-six species of Entomophthorales were classified considering their ability to utilize mineral or organic nitrogen, metabolize oxydized or reduced form of S and synthetize vitamins. Intergeneric, interspecific but also intraspecific variations were found concerning the nutritional requirements of the 73 strains studied.

[Taxonomic reconsideration of Entomophthora obscura Hall & Dunn]. / Reconsidération toxonomique de Entomophthora obscura Hall et Dunn.

A set of slides and strains designated as Entomophthora thaxteriana Petch, E. obscura Hall et Dunn and E. ignobilis Hall et Dunn were compared on morphological, physiological, pathological and biochemical bases. It is concluded that E. thaxteriana (name invalidated by Humber, 1978) must be replaced by E. obscura and not by E. ignobilis, this species being considered as nomen dubium. Some intraspecific variations within the species E. obscura were found particularly with regard to the ability to produce resting spores and cystidia.