Efecto de la combinación de Metarhizium anisopliae y Gliocladium virens sobre la oviposición, eclosión y emergencia de Aedes aegypti / Effect of the combination of Metarhizium anisopliae and Gliocladium virens on the oviposition, hatching and emergency of Aedes aegypti

Resumen: Objetivo: Evaluar el efecto de la combinación de Metarhizium anisopliae y Gliocladium virens, ambos con Aqua Reslin Super, sobre oviposición, eclosión y emergencia de Aedes aegypti. Material y métodos: Se realizaron evaluaciones para determinar el efecto de los tratamientos impregnados en papel filtro y expuestos dentro de recipientes de plástico sobre la oviposición, eclosión y emergencia de Aedes aegypti. Resultados: Los resultados indicaron que las combinaciones hongo e insecticida no afectaron el comportamiento de oviposición, pero sí la eclosión de los huevos y la emergencia del adulto. Conclusión: Con los resultados se puede concluir que la combinación de hongos + insecticida puede ser una buena opción para aplicarse en sitios de oviposición con miras al desarrollo de una ovitrampa letal.

Abstract: Objective: To evaluate the effect of the combination of Metarhizium anisopliae and Gliocladium virens, both with Aqua Reslin Super, on the oviposition, hatching and emergence of Aedes aegypti. Materials and methods: Evaluations were carried out to determine the effect of treatments impregnated on filter paper and exposed within plastic containers on the oviposition, hatching and emergency of Aedes aegypti. Results: The results indicated that the fungus and insecticide combinations did not affect the oviposition behavior, but if the hatching of the eggs and the adult's emergency. Conclusion: With the results it can be concluded that the combination of fungi + insecticide can be a good option to be applied in oviposition sites with a view to the development of a lethal ovitrap.

A new coumarin derivative, 4-acetatecoumarin, with antifungal activity and association study against Aspergillus spp

Abstract Fungal infections have become a concern for health professionals, and the emergence of resistant strains has been reported for all known classes of antifungal drugs. Among the fungi causing disease, we highlight those that belong to the genus Aspergillus. For these reasons, the search for new antifungals is important. This study examines the effects of a coumarin derivative, 4-acetatecoumarin (Cou-UMB16) both alone and together with antifungal drugs, and its mode of action against Aspergillus spp. Cou-UMB16 was tested to evaluate its effects on mycelia growth, and germination of Aspergillus spp. fungal conidia. We investigated its possible action on cell walls, on the cell membrane, and also the capacity of this coumarin derivative to enhance the activity of antifungal drugs. Our results suggest that Cou-UMB16 inhibits Aspergillus spp. virulence factors (mycelia growth and germination of conidia) and affects the structure of the fungal cell wall. When applying Cou-UMB16 in combination with azoles, both synergistic and additive effects were observed. This study concludes that Cou-UMB16 inhibits mycelial growth and spore germination, and that the activity is due to its action on the fungal cell wall, and that Cou-UMB16 could act as an antifungal modifier.

Anti-fungal potential of ozone against some dermatophytes

ABSTRACT Dermatophytes are classified in three genera, Epidermophyton, Microsporum and Trichophyton. They have the capacity to invade keratinized tissue to produce a cutaneous infection known as dermatophytoses. This investigation was performed to study the effect of gaseous ozone and ozonized oil on three specific properties of six different dermatophytes. These properties included sporulation, mycelia leakage of sugar and nutrients and the activity of their hydrolytic enzymes. Generally, ozonized oil was found to be more efficacious than gaseous ozone. Microsporum gypseum and Microsporum canis were the most susceptible, while Trichophyton interdigitale and T. mentagrophytes were relatively resistant. The study revealed a steady decline in spore production of M. gypseum and M. canis on application of ozonated oil. An increase in leakage of electrolytes and sugar was noticed after treatment with ozonized oil in the case of M. gypseum, M. canis, T. interdigitale, T. mentagrophytes and T. rubrum. The results also revealed loss in urease, amylase, alkaline phosphatase, lipase and keratinase enzyme producing capacity of the investigated fungi.

Conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans: influence of growth conditions and antifungal susceptibility profiles

In the present study, we have investigated some growth conditions capable of inducing the conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans. Germination in Sabouraud medium (pH 7.0, 37ºC, 5% CO2) showed to be a typically time-dependent event, reaching ~75% in S. minutisporum and > 90% in S. apiospermum, S. aurantiacum and L. prolificans after 4 h. Similar germination rate was observed when conidia were incubated under different media and pHs. Contrarily, temperature and CO2 tension modulated the germination. The isotropic conidial growth (swelling) and germ tube-like projection were evidenced by microscopy and cytometry. Morphometric parameters augmented in a time-dependent fashion, evidencing changes in size and granularity of fungal cells compared with dormant 0 h conidia. In parallel, a clear increase in the mitochondrial activity was measured during the transformation of conidia-into-germinated conidia. Susceptibility profiles to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin varied regarding each morphotype and each fungal species. Overall, the minimal inhibitory concentrations for hyphae were higher than conidia and germinated conidia, except for caspofungin. Collectively, our study add new data about the conidia-into-hyphae transformation in Scedosporium and Lomentospora species, which is a relevant biological process of these molds directly connected to their antifungal resistance and pathogenicity mechanisms.

Morphological changes and growth of filamentous fungi in the presence of high concentrations of PAHs

In this study, we evaluated the effect of low and high molecular weight polycyclic aromatic hydrocarbons (PAHs), i.e., Phenanthrene, Pyrene and Benzo[a]pyrene, on the radial growth and morphology of the PAH-degrading fungal strains Aspergillus nomius H7 and Trichoderma asperellum H15. The presence of PAHs in solid medium produced significant detrimental effects on the radial growth of A. nomius H7 at 4,000 and 6,000 mg L⁻¹ and changes in mycelium pigmentation, abundance and sporulation ability at 1,000–6,000 mg L⁻¹. In contrast, the radial growth of T. asperellum H15 was not affected at any of the doses tested, although sporulation was observed only up to 4,000 mg L⁻¹ and as with the H7 strain, some visible changes in sporulation patterns and mycelium pigmentation were observed. Our results suggest that fungal strains exposed to high doses of PAHs significantly vary in their growth rates and sporulation characteristics in response to the physiological and defense mechanisms that affect both pigment production and conidiation processes. This finding is relevant for obtaining a better understanding of fungal adaptation in PAH-polluted environments and for developing and implementing adequate strategies for the remediation of contaminated soils.

Effect of surfactants and temperature on germination and vegetative growth of Beauveria bassiana

Three non-ionic surfactants: Tween20, Tween80 and Breakthru® were screened for their effects on spore germination and mycelial growth rates and for their influence on three isolates of Beauveria bassiana spore germination at various temperatures. Tween20 and Tween80 were compatible with all the B. bassiana isolates in the germination studies, but inhibited germination at higher surfactant concentrations, irrespective of the conidial concentrations. Breakthru® had an inhibitory effect on germination even at the lowest concentration of 0.1% on all the B. bassiana isolates. The effects of the surfactants on spore germination did not correspond with their effects on colony growth. Conidial viability within the same formulation declined significantly with increases in temperature, irrespective of the surfactant. The optimal temperature for conidial germination of B. bassiana isolates was approximately 25 °C with an upper limit at 30 °C. Isolate 7320 was identified as the least affected by the different surfactants. This isolate was able to germinate rapidly in a broad temperature range of 25–30 °C after 24 h, this characteristic being an essential factor in controlling house fly populations in poultry houses.

Efecto antifúngico de extractos fenólicos y de carotenoides de chiltepín (Capsicum annum var. glabriusculum) en Alternaria alternata y Fusarium oxysporum / Antifungal effect of phenolic and carotenoids extracts from chiltepin (Capsicum annum var. glabriusculum) on Alternaria alternata and Fusarium oxysporum

En el presente estudio se evaluó el efecto de extractos fenólicos y de carotenoides procedentes de frutos de chiltepín sobre el crecimiento micelial y la germinación de conidios de Alternaria alternata y Fusarium oxysporum, 2 importantes hongos causantes de podredumbres en frutas y hortalizas. Los extractos fenólicos presentaron una inhibición en el crecimiento micelial de A. alternata del 38,46 %, y redujeron significativamente la germinación de conidios al quinto día después del tratamiento al 92 % en relación al control. No se observaron cambios significativos en el crecimiento micelial de F. oxysporum, pero sí se redujo significativamente al 85 % en relación al control, el número de conidios germinados a los 5 días de tratamiento. Los extractos de carotenoides mostraron una inhibición del 38,5 % en el crecimiento micelial y del 85,3 % en la germinación de conidios de A. alternata, 5 días después del tratamiento. Frente a F. oxysporum, dichos extractos presentaron menor inhibición del crecimiento micelial (20,3 %), mientras que hubo una mayor inhibición en la germinación de conidios (96 %). Los extractos fenólicos y de carotenoides de chiltepín pueden ser una alternativa promisoria de importancia agrícola como fungicidas naturales.

The effect of phenolic and carotenoid extracts from chiltepin fruits on mycelial growth and the inhibition of conidial germination of Alternaria alternata and Fusarium oxysporum were investigated in the present work. Phenolic extracts inhibited mycelial growth of A. alternata by 38.46%, and significantly reduced conidial germination on the fifth day after treatment to 92% in relation to control. No significant changes were observed in the inhibition of mycelial growth in Fusarium oxysporum; however, the number of germinated conidia was reduced, showing 85% inhibition five days after treatment in relation to control. Moreover, carotenoid extracts showed 38.5% inhibition of mycelial growth and 85.3% inhibition of conidial germination of A. alternata, five days after treatment. Carotenoid extracts showed less inhibition of mycelial growth (20.3%) in F. oxysporum, with respect to A. alternata; while there was greater inhibition of conidial germination (96%) on the fifth day after treatment. Phenolic and carotenoid extracts from chiltepin may be a promising alternative as a natural fungicide against fungi of agricultural importance.

Carum copticum and Thymus vulgaris oils inhibit virulence in Trichophyton rubrum and Aspergillus spp

Emergence of drug-resistant strains has demanded for alternative means of combating fungal infections. Oils of Carum copticum and Thymus vulgaris have long been used in ethnomedicine for ailments of various fungal infections. Since their activity has not been reported in particular against drug-resistant fungi, this study was aimed to evaluate the effects of oils of C. copticum and T. vulgaris on the growth and virulence of drug-resistant strains of Aspergillus spp. and Trichophyton rubrum. The gas chromatography-mass spectrometry analysis revealed thymol constituting 44.71% and 22.82% of T. vulgaris and C. copticum, respectively. Inhibition of mycelial growth by essential oils was recorded in the order of thymol > T. vulgaris > C. copticum against the tested strains. RBC lysis assay showed no tested oils to be toxic even up to concentration two folds higher than their respective MFCs. Thymol exhibited highest synergy in combination with fluconazole against Aspergillus fumigatus MTCC2550 (FICI value 0.187) and T. rubrum IOA9 (0.156) as determined by checkerboard method. Thymol and T. vulgaris essential oil were equally effective against both the macro and arthroconidia growth (MIC 72 µg/mL). A > 80% reduction in elastase activity was recorded for A. fumigatus MTCC2550 by C. copticum, T. vulgaris oils and thymol. The effectiveness of these oils against arthroconidia and synergistic interaction of thymol and T. vulgaris with fluconazole can be exploited to potentiate the antifungal effects of fluconazole against drug-resistant strains of T. rubrum and Aspergillus spp.

Growth of in vitro Fusarium oxysporum f. sp. niveum in chemically defined media amended with gallic acid

Gallic acid was artificially added to the media to grow Fusarium oxysporum f.sp.niveum to investigate its effect on the pathogenic fungus. Results indicate that gallic acid inhibited the growth of F. oxysporum f.sp.niveum. The colony diameter, the conidia germinating rate and the conidia yield were reduced by 5.7-22.9 percent percent, 35.8-55.6 percent and 38.9-62.2 percent respectively. However, the virulence factors by the fungus were stimulated. The activity of pectinase, proteinase and cellulase increased by 12.3-627.8 percent, 11.8-41.2 percent and 0.5-325.0 percent respectively, while the activity of amylase increased slightly. The results suggest that gallic acid repressed growth but facilitated the relative pathogenicity of invading pathogens.

Human anti-rhinosporidial antibody does not cause metabolic inactivation or morphological damage in endospores of Rhinosporidium seeberi, in vitro.

This report describes the use of the MTT-reduction and Evan's blue-staining tests for the assessment of the viability and morphological integrity, respectively, of rhinosporidial endospores after exposure to sera from rhinosporidial patients with high titres of anti-rhinosporidial antibody. Sera from three patients, with nasal, ocular and disseminated rhinosporidiosis respectively were used, with human serum without anti-rhinosporidial antibody for comparison, with or without added fresh guinea pig serum as a source of complement. All four sera tested, with or without guinea-pig serum, had no effect on the morphological integrity or the viability of the endospores and it is suggested that anti-rhinosporidial antibody has no direct protective role against the endospores, the infective stage, in rhinosporidiosis. This finding is compatible with the occurrence of chronicity, recurrence and dissemination that are characteristic of rhinosporidiosis despite the presence of high titres of anti-rhinosporidial antibody in patients with these clinical characteristics. The possible occurrence of humoral mechanisms of immunity that involve anti-rhinosporidial antibody with cells such as leucocytes and NK cells, in vivo, cannot yet be discounted, although the presence of high titres of anti-rhinosporidial antibody in patients with chronic, recurrent and disseminated lesions might indicate that such antibody is non-protective in vivo.

Effect of myoinositol on sporangiospore-yeast transformation of Mucor circinelloides Tieghem cultivated in synthetic broth.

Mucor species exhibit fungal dimorphism in controlled environments. In this work, we examined the effect of myoinositol supplementation on the growth and morphology of Mucor circinelloides. Using sporangiospores as inoculums, diverse morphologies were induced in synthetic broth incubated at pH 4.5, temp. 20 degrees C, ambient. The morphologies included thallic suptypes (holoblastic-, holothallic-, enterothallic conidia as well as vesicular conidial headgroups), which were determinate in growth, and proliferating yeast forms. Analysis of variance, p<0.05, showed that time had significant impact on growth. A separation of means, l.s.d. 14.34, p<0.05, indicated that myoinositol supplementation at 500 microM supported the least growth, but 2.0-3.0 mM levels had the higher values, and this was followed by the control, 300 microM, 1.0, 2.0, 5.0 mM supplementations. Although the predominant morphology, that is, terminal budding yeast cells was not quantitated, observation showed that it was more preponderant, had optimal size and cell shape became more regular at 2.0 mM myoinositol supplementation.

Sensitivity of ornithophillic fungi to some drugs.

The occurrence of ornithophillic fungi and related dermatophytes was evaluated from the poultry farm soil samples. Two test species of Microsporum were tested by 'Spore germination' and 'Disc diffusion method' against the two well known antifungal antibiotics i.e. griseofulvin and mycostatin (polyene antibiotic). The data showed cent percent inhibition of fungal spore germination and increased zone of inhibition at higher doses. The antimicrobial drugs including acetyl salicylic acid, benzoic acid and boric acid were also assessed at different doses against the test organisms. Acetyl salicylic acid and boric acid were found to be toxic at higher doses, while these pathogens seems to be somewhat resistant for benzoic acid. It is suggested that the effective doses of these drugs should also be tried for allergic effects on birds and other animals before commercial use.

In vitro evaluation of sulfadrugs against fungi causing otomycosis.

The efficacy of four sulfadrugs i.e., sulfadiazine, sulfamethoxazole, sulfaguanidine and sulfamoxole were taken in different doses (500, 1000, 1500, 2000 and 2500 ppm) to test their effectiveness against five pathogenic organisms for the control of mycelial growth and sporulation. Amongst the drugs tested sulfamethoxazole seems to be most effective against most of the test fungi showing 96.78, 90.53, 86.62, 54.16 and 43.91 percent inhibition in mycelial growth of P. nigricans, A. flavus, A. corymbifera, A. niger and C. albicans, respectively at its 2500 ppm dose in the basal medium. Gradual reduction in sporulation in all the test organisms almost in all the sulfadrugs have caused inhibition in sporulation, in comparison to their respective controls. Maximum inhibitory effect of sulfadiazine was recorded in A. niger showing 77.26 percent inhibition in the mycelial growth at a dose of 2500 ppm. Sulfaguanidine at its higher dose i.e., 2500 ppm proved to be most toxic against A. corymbifera causing 56.39 percent inhibition in the mycelial growth, while the same dose could not be found much effective against other test fungi. Sulfamoxole was found to be quite effective against most of the test fungi causing 47.16 to 85.86 percent inhibition in the mycelial growth. A gradual inhibition in the vegetative growth and sporulation or budding in all the test fungi was noted by increasing the concentrations of the test sulfadrugs.

In vitro evaluation of medicinal plant extracts against Pestalotiopsis mangiferae.

A serious leaf-spot disease of Mangifera indica was noted during the last 10 years in Satpura plateau of India. On the basis of characteristic symptoms and cultural characters, the pathogen was identified as Pestalotiopsis mangiferae which is hitherto not reported from Satpura plateau of India. Screening of 17-medicinal plants against the test pathogen revealed 14 antimycotic whereas 3-plants, viz., Argemone mexicana, Caesalpinia bonducella, and Casia fistula acclerated the growth of the pathogen. The maximum activity was shown by Eucalyptus globulus (88%) and Catharanthus roseus (88%) followed by Ocimum sanctum (85.50%), Azadirachta indica (84.66%), Ricinus communis (75%) and Lawsonia inermis (74.33%) while the minimum activity was exhibited by Jatropha curcas (10%).

Metal uptake by mycelia during submerged growth and by sporocarps of an edible fungus Volvariella volvacea.

Uptake of a few metals by V. volvacea was determined during submerged growth of the organism in sublethal concentration of each metal salt. The uptake of Pb2+ and Hg2+ was 5 and 5.23 micrograms g-1 respectively while that of Cu2+ was 500 micrograms g-1 under experimental conditions. Treatment of spawned substrate separately with different metal salts showed maximum and minimum uptake of Pb2+ (100 micrograms g-1) and Cd2+ (2.93 micrograms g-1) respectively by sporocarps. All metal salts at test concentrations reduced biological efficiency of sporocarp production but markedly by Co2+. Cd2+ and Co2+ were highly toxic to mycelia and sporocarps respectively. The uptake of Cu2+ by mycelia and Pb2+ by sporocarps were highest among the five metals tested. Metal toxicity, tolerance and uptake capacity of V. volvacea differ considerably with concentration of metal ions.

Sporostatic effect of some oils against fungi causing otomycosis.

In vitro animycotic effect of mustard, groundnut, soybean, coconut and amla oils on five fungi i.e., Aspergillus niger, A. flavus, Absidia corymbifera, Penicillium nigricans and Candida albicans isolated from otitic fungal infection of external ear (Tympanic membrane) of human being was studied. Spore germination was evaluated in the oil samples as such after heating for two minutes & after boiling the oil. Data show that mustard and coconut oil seem to be effective as in these the spore germination was poor. Other oils were not found to be much effective. Sporostatic effect was noted only when the oils were used after heating or boiling this may be correlated by the synthesis of enzymes during spore germination.

Studies of the antifungal compounds produced by Erwinia herbicola.

The organic phase of a wide spectrum, antimycotic and diffusable toxin from Erwinia herbicola showed a highly significant inhibitory activity against Pyricularia oryzae spores in spore well bioassay. Germ tube lengths were inhibited more in wells containing 5 microliters equivalent of bacterial toxin than 1 microliter. No significant difference between the germ tube in an equal mixture of Dimethyl sulphoxide: ethanol and controls. Thin layer chromatography using the chloroform extraction of the organic phase showed a significant antagonism on Cladosporium cucumerinum. The retardation factor values for inhibitory zones in solvent 1 were 0.07 for lower spot and 0.26 for upper spot.