Sporulation, radial growth and biomass production of A. robusta and M. thaumasium submitted to different methods of preservation

Abstract

Biological control is based on the use of microorganisms to combat populations of a specific pathogen. Nematophagous fungi have shown to be promising agents to combat nematode parasites of plants and animals. These organisms produce special structures along the hyphae, named traps, which are responsible for capturing and killing the nematode pre-parasitic stages. The growth of the isolates I31 of Arthrobotrys robusta and NF34a of Monacrosporium thaumasium was studied after submission to four different methods of preservation during eighteen months. The isolates were stored at 4ºC and cryopreserved with or without addition of cryoprotectants and stored in silica gel. The isolates did not present variation in radial growth when stored at 4ºC and frozen with or without addition of cryoprotectants. There was no significant difference between the dry mycelial mass of the isolates stored at 4ºC and those frozen after the addition of cryoprotectants. Storage in silica gel and freezing without cryoprotection interfered negatively in the capacity of the fungi to produce mycelial mass. This characteristic also was observed for sporulation of the two isolates. The behaviour of the isolates when maintained for prolonged periods under laboratory conditions is an important factor for selection of the most efficient method of preservation.

Synthesis ofN-Alkyl-β-d-glucosylamines and Their Antimicrobial Activity againstFusarium proliferatum,Salmonellatyphimurium, andListeria innocua

“…The antifungal activity of glucosylamines was evaluated by radial growth assays , on PDA medium with different concentrations of bioactive agents. The bioactive agents HeGPA, OcGPA, and DoGPA were incorporated into the culture medium using methanol as solvent.…”

“…Overnight precultures were performed as follows: L. innocua and S. typhimurium were grown in tryptose broth (Difco 262200) and nutrient broth (Difco 234000), respectively at 37 °C for 18 h. Antifungal Activity Assessment. The antifungal activity of glucosylamines was evaluated by radial growth assays (43,45) on PDA medium with different concentrations of bioactive agents. The bioactive agents HeGPA, OcGPA, and DoGPA were incorporated into the culture medium using methanol as solvent.…”

Inhibitory Activities of Griseofulvin and Its Analogues against Phytopathogenic Fungi

“…Mycelial growth assay: The antifungal activity of compounds was evaluated by the mycelial growth assay [20][21][22] , conducted on PDA medium. Prior to the fungal inoculation, 100 µL of different concentrations of the tested compounds were poured and spread on the surface of the agar medium.…”

Viability of Beauveria bassiana isolates after storage under several preservation methods

“…In the lyophilized isolate, due to the lack of germinated spores, it was not possible to evaluate the number of spores produced by the colonies. It is known that repeated sub-cultures can lead to changes in some of the characteristics of fungi, such as a decrease on the ability to sporulate (Nakasone et al 2004), and some fungal species have their sporulation ability decreased when storage with glycerol freeze, when compared to storage in medium at 4°C (Mota et al 2003).…”