Culicinomyces Clavisporus Research Articles

The transcriptome of the entomopathogenic fungus Culicinomyces clavisporus contains an ortholog of the insecticidal ribotoxin Hirsutellin.

The entomopathogenic fungus Culicinomyces clavisporus is known to infect and kill mosquito larvae and therefore has been seen as a potential biological control agent against disease vector mosquitoes. Whereas most fungal entomopathogens infect hosts by penetrating the external cuticle, C. clavisporus initiates infection through ingestion (per os). This unique infection strategy suggests that the C.clavisporus genome may be mined for novel pathogenicity factors with potential for vector control. To this end, an Isoseq-based transcriptome analysis was initiated, and resulted in a total of 3,512,145 sequences, with an average length of 1,732 bp. Transcripts assembly and annotation suggested that the C. clavisporus transcriptome lacked the cuticle-degrading proteins that have been associated with other entomopathogenic fungi, supporting the per os pathogenicity process. Furthermore, mining of the sequence data unexpectedly revealed C. clavisporus transcripts homologous to the Hirsutellin toxin. Comparative sequence analyses indicated that the C. clavisporus Hirsutellin predicted protein has retained the canonical molecular features that have been associated with the ribotoxic and insecticidal properties of the original toxin isolated from Hirsutella thompsonii. The identification of an Hirsutellin ortholog in C. clavisporus was supported by phylogenetic analyses demonstrating that Culicinomyces and Hirsutella were closely related genera in the Ophiocordycipitaceae family. Validation of the mosquitocidal activity of this novel C. clavisporus protein has yet to be performed but may help position Hirsutellin orthologs as prime candidates for the development of alternative biocontrol approaches complementing the current toolbox of vector mosquito management strategies.

Evaluation of culture filtrates of Culicinomyces clavisporus: Mycoadulticide for Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi

The Culicinomyces clavisporus is a fungal pathogen of a wide range of mosquito larvae. The C. clavisporus was isolated from the larvae of Culiseta inornata. We have investigated into potential pathogenicity against the adults of Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi. The culture filtrates released from the strain of C. clavisporus 46258 were grown in the EmYPss broth, were filtered and used for the bioassays after a growth of 15days. The results demonstrated these metabolites with LC(50), LC(90) and LC(99) values of C. quinquefasciatus, 5.62, 8.71 and 12.59, A. aegypti, 3.0, 7.0 and 9.3, and A. stephensi 2.69, 6.0 and 7.24μl/cm(2), respectively after exposure for 24h. These results compared favorably with the commercial adulticide Gokilaht(®)-S 5EC (d,d-trans-cyphenothrin) that showed 100% mortality at the same concentration. This study successfully identified that the metabolites of C. clavisporus can be used as mosquitoes adulticide as safer alternative to modern synthetic chemical insecticide against mosquito vector of diseases. Further purification can lead to biotechnological exploitation.

Studies on Fungal Cultural Filtrates against Adult Culex quinquefasciatus (Diptera: Culicidae) a Vector of Filariasis.

Entomopathogenic fungi have significant potential to control mosquito population. The culture filtrates of Fusarium oxysporum, Lagenidium giganteum, Trichophyton ajelloi, and Culicinomyces clavisporus were evaluated against adults of Cx. quinquefasciatus. The culture filtrates were obtained by filtering the broth through Whatman-1 filter paper. These culture filtrates of C. clavisporus have been found significantly pathogenic with LC50-2.5, LC90-7.24, and LC99-8.7 ML, respectively, after exposure of 24 h. However, the culture filtrates when were combined, in ratios 1 : 1 : 1 of Fusarium oxysporum, Lagenidium giganteum, Trichophyton ajelloi the mortalities were significantly increased. The LC50-3.71, LC90-8.12, and LC99-11.48 were significantly recorded after exposure of 10 hrs. Similarly, the culture filtrates of T. ajelloi, Culicinomyces clavisporus, and L. giganteum have been combined in ratios 1 : 1 : 1. Similarly the LC50-1.94, LC90-4, and LC99-6.16 ML Were recorded after exposure of 10 hrs. The results of present study show promise for the use of selected fungal metabolites for control of Cx. quinquefasciatus in the Laboratory.

In vitro susceptibility to fungicides by invertebrate-pathogenic and saprobic fungi

The effect of five fungicides, benomyl (1 mg/l), dodine (50 mg/l), manzate (100 mg/l), cupric sulphate (200 mg/l) and thiabendazole (4 mg/l) was tested under in vitro conditions on development of 15 isolates of fungi pathogenic for insects and other invertebrates (Beauveria brongniartii, Culicinomyces clavisporus, Duddingtonia flagrans, Hirsutella thompsonii, two Metarhizium anisopliae, Nomuraea rileyi, two Isaria/Paecilomyces spp., and Sporothrix insectorum) and 13 isolates of contaminant fungi (five Aspergillus spp., Cladosporium cladosporioides, Cunninghamella echinulata, Fusarium roseum, Gliocladium sp., Mortierella isabellina, Mucor plumbeus, Rhizopus arrhizus and Trichothecium roseum) originating mostly from tree-hole breeding sites of mosquitoes. Most pathogenic and contaminant fungi had clear patterns of susceptibility or resistance to tested concentration of the fungicide. Development of both pathogenic and contaminant fungi on fungicide-supplemented medium varied among fungi and fungicides tested. Minimal inhibition of pathogenic fungi was found for cupric sulphate, benomyl, dodine, thiabendazole < manzate. The highest inhibition of contaminants was obtained with thiabendazole > benomyl and dodine > manzate and cupric sulphate. Thiabendazole was the most appropriate fungicide to isolate fungi pathogenic to invertebrates from substrates with high water contents and rich in organic material. The results underline the importance of adapting both a fungicide and its concentration for a selective medium for isolating specific target fungi and while selecting against possible contaminants.

Culicinin D, an Antitumor Peptaibol Produced by the Fungus Culicinomyces clavisporus, Strain LL-12I252

A group of new 10mer linear peptides, designated culicinins A-D (1-4), was isolated from the fermentation broth of the entomopathogenic fungus Culicinomyces clavisporus, strain LL-12I252. The structures of the culicinins were determined by a combination of 2D NMR and MS analysis. The major compound, culicinin D (4), exhibited selective inhibitory activity against PTEN-negative MDA468 tumor cells. Studies on the 3D structure of 4 using NOE data and computer modeling revealed a dominant conformation of the right-handed helix.

Genetic Transformation of the Mosquito Pathogenic Fungus Culicinomyces clavisporus

The mosquito fungal pathogen Culicinomyces clavisporus was found to be sensitive to the antibiotics hygromycin B and phleomycin but resistant to kanamycin and geneticin. Protoplasts were genetically transformed to give strains resistant to phleomycin and hygromycin B. The results show that multiple integrations of transforming DNA can occur and that heterologous fungal gene expression signals are functional in C. clavisporus .

Effects of Drying and Rehydration on Mycelia of the Mosquito Pathogenic Fungi Culicinomyces Clavisporus and Tolypocladium Cylindrosporum

Effects of Drying and Rehydration on Mycelia of the Mosquito Pathogenic Fungi <i>Culicinomyces Clavisporus</i> and <i>Tolypocladium Cylindrosporum</i>

Effects of Drying and Rehydration on Mycelia of the Mosquito Pathogenic Fungi Culicinomyces clavisporus and Tolypocladium cylindrosporum

On montre que la plupart des hyphes sont tries pendant le processus de sechage/rehydratation. Ces resultats confirment la necessite d'optimiser les methodes de preparation des myceliums deshydrates de champignons entomopathogenes pour la lutte contre les insectes

A procedure for preservation of the mosquito pathogen Culicinomyces clavisporus

An effective storage procedure has been demonstrated for the mosquito pathogen Culicinomyces clavisporus. A mycelial preparation was harvested by filtration, sprayed with a sucrose solution and air dried at 20°C in a laminar flow cabinet until the mycelial mat became crisp. This material was then ground in a hammer mill and particles of less than 355 μm were sieved out. Viability of the particles was assessed by studying mycelial growth and conidial formation when particles were added to water agar plates or to water. The particles retained 100% viability after 9 weeks storage at-20°C or 6 days at 4°C. Preparations lost activity rapidly if stored at 20°C. Conidia produced by this method were pathogenic to mosquito larvae.

Laboratory studies on the recycling potential of the mosquito pathogenic fungus Culicinomyces clavisporus

Sporulation of Culicinomyces clavisporus developed on 87–95% of first-instar Culex quinquefasciatus larvae within 5 days after exposure to the fungus in the laboratory. On these larvae the most frequent site of sporulation was the posterior abdominal segments. Conidia remained on the cadavers for at least 3 weeks and after this time their viability was 70–90%. Spore production on cadavers selected with sporulation on the entire cuticle of the thorax and abdomen was 7.4 × 10 4 conidia per first-instar larva and 9.4 × 10 5 conidia per fourth-instar larva. However, this degree of sporulation was only obtained in 11.2% of infected first-instar larvae in these experiments. With unselected first-instar larvae chosen at random from test trays spore production was 2.9 × 10 4 conidia per larva when the test inoculum was applied at a concentration of 10 3 conidia/ml and 5.9 × 10 3 conidia per larva when the test inoculum was 10 6 conidia/ml. Comparative bioassays showed that conidia produced in vivo were more potent than those produced in vitro in four out of six assays using Aedes aegypti larvae as test insects.

SEASONAL OCCURRENCE OF THE MOSQUITO PATHOGENIC FUNGUS CULICINOMYCES CLAVISPORUS IN A NATURAL HABITAT

AbstractA longitudinal study to investigate the natural hosts and occurrence of the mosquito pathogenic fungus, Culicinomyces clavisporus was conducted at the Nattai River, Mittagong, New South Wales. The fungus was isolated from Aedes rupestris on 16 occasions, Aedes rubrithorax on 1 occasion, Aedes sp. on 1 occasion, Dasyhelea sp. on 8 occasions, a Chironomidae larva on 1 occasion and moist sediment once. With the exception of 1 isolate, which was from an Aedes larva in a groundpool, all of the infected larvae were collected from small rockpools on a trachyte weir. The study indicated the fungus did not persist and recycle in those rockpools but was washed in when river levels rose. The occurrence of the fungus had a seasonal bias, with 24 of 28 isolates obtained in the cooler months of April to August. Possible reasons for this are discussed.

A simple method for mass culturing entomopathogenic hyphomycete fungi

A simple and inexpressive method for culturing entomopathogenic fungi using pans, bran, cellophane and autoclave bagss is described. With this method, large quantities of fungus can be obtained free from substrate contimination. Conidial yields of 10 10 · g −1 dry biomass were obtained for Tolypocladium cylindrosporum, Verticillium lecanii, and Beauveria bassiana; 10 9 for Metarhizium anisopliae; and 10 8 for Culicinomyces clavisporus.

NON‐SUSCEPTIBILITY OF APIS MELLIFERA TO CULICINOMYCES CLAVISPORUS

AbstractThe commercial honey bee Apis mellifera was exposed to the mosquito pathogenic fungus Culicinomyces clavisporus. The examination of adults and larvae, sampled from an inoculated hive failed to detect any evidence of fungal invasion. Adult bees maintained in the laboratory at 27 °C and fed a fungal suspension were also found to be not susceptible.

Studies on the Mosquito Pathogenic Hyphomycete Culicinomyces Clavisporus

In 1982, the hyphomycete Culicinomyces clavisporus was isolated from larvae ofCuliseta inornata collected from a pond in Alberta, Canada. Previously, the fungus was known only from areas around Chapel Hill, North Carolina, and Sydney, Australia. Culiseta inornata is a new host record for this fungus. The Canadian isolate was compared with isolates from the U.S. and Australia with regard to growth rate on solid media, colonial morphology and pigmentation, and growth in a liquid medium. The Canadian and Australian isolates were more similar to each other than to the American isolate. Observations by scanning electron microscopy and light microscopy revealed that all three isolates produce conidia of two sizes, and that the conidia are produced from phialides having more than one neck (polyphialides). In 1983, Culicinomyces clavisporus was isolated again from larvae of Culiseta inornata col? lected in a marsh adjacent to the first site.

INHIBITION OF CULICINOMYCES CLAVISPORUS INVASION IN SOIL DWELLING CHIRONOMUS SP.

AbstractIn laboratory experiments Chironomus sp. larvae, exposed to the Australian strain of the mosquito pathogenic fungus Culicinomyces clavisporus Couch, Romney and Rao, were infected in the absence of a substrate but were not infected when given a substrate in which to tunnel and construct their cases. Possible reasons for this are discussed