https://cyberleninka.org/article/n/966059.pdf

Fungal pollution of indoor environments and its management.

The use of entomopathogenic fungi for the management of insect pests has been steadily gaining popularity over the last 50 years. Each year, more and more fungi are being commercialized all over the world for inundative applications (e.g. mycoinsecticides) and inoculative release. Appreciation for their human and environmental safety is increasing because of concerns about the adverse impacts of chemical insecticides. Inundative use requires the production of very large numbers of the infectious stages of these spores, including aerial conidia, blastospores, submerged (microcycle) conidia, marcescent mycelium, and microsclerotia. Considerable advances in mass production have occurred in response to the increasing popularity. This chapter examines the state of the art of fungus mass production, particularly during the past 30 years.

Mass Production of Entomopathogenic Fungi: State of the Art

The infection processes of Sclerotinia sclerotiorum in cotyledon tissue of a resistant and a susceptible genotype of Brassica napus

Ten strains of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were evaluated to find the most effective strain for optimization studies. The first criterion tested for strain selection was the mortality (> 50%) of Spodoptera litura larvae after inoculation of the fungus for 4 days. Results on several bioassays revealed that B. bassiana BNBCRC showed the most virulence on mortality S. litura larvae (80% mortality). B. bassiana BNBCRC also showed the highest germination rate (72.22%). However, its conidia yield (7.2 × 10(8) conidia/mL) was lower than those of B. bassiana B 14841 (8.3 × 10(8) conidia/mL) and M. anisopliae M6 (8.2 × 10(8) conidia/mL). The highest accumulative radial growth was obtained from the strain B14841 (37.10 mm/day) while the strain BNBCRC showed moderate radial growth (24.40 mm/day). M. anisopliae M6 possessed the highest protease activity (145.00 mU/mL) while M. anisopliae M8 possessed the highest chitinase activity (20.00 mU/mL) during 96~144 hr cultivation. Amongst these criteria, selection based on virulence and germination rate lead to the selection of B. bassiana BNBCRC. B. bassiana B14841 would be selected if based on growth rate while M. anisopliae M6 and M8 possessed the highest enzyme activities.

Evaluation of Strains of Metarhizium anisopliae and Beauveria bassiana against Spodoptera litura on the Basis of Their Virulence, Germination Rate, Conidia Production, Radial Growth and Enzyme Activity

Disclosed herein are pest controlling compositions comprising entomopathogenic fungi which are horizontally transmissible across pest populations and control target pests at various life stages. Further disclosed are methods of using such compositions for controlling pests, including, bed bugs and other invasive parasitic pests.

Compositions and methods for treating pests

The concern for the development of hyphomycete fungi as suitable biocontrol agents of insect pests leads to the isolation of various insect pathogenic fungi. Amongst them, one of the most studied entomopathogenic fungus is Beauveria bassiana. The conidia of mitosporic fungi adhere to the host cuticle and germinate to produce an infectious propagule, and produce a sequential release of extra cellular enzymes to breach the insect cuticle. Protease is one of the most important and earliest enzymes involved in the host invasion. Extracellular protease production by seventeen B. bassiana isolates was investigated in the present study. High protease activity was observed during four to six days of culture incubation. Induction mechanism of subtillisin type Pr1 and trypsin type Pr2 activity were investigated utilizing different media. Minimal medium supplemented with casein (1%) showed high protease production and minimal medium supplemented with colloidal chitin (2%) was also able to induce Pr1 activity. The pH, ammonia and oxalic acid production in in vitro conditions was also investigated and the alteration in pH for protease production was not significant irrespective of the medium used. The protease activity gel was also studied and a common 66 kDa protease was observed in all the seven isolates studied.

	 

	Key words: Ammonia, B. bassiana, oxalic acid, subtillisin type Pr1, trypsin type Pr2, protease, pH.

https://www.isabb.academicjournals.org/article/article1380102908_Dhar and kuar.pdf

Production of cuticle - degrading proteases by Beauveria bassiana and their induction in different media

Protease production by fourteen M. anisopliae isolates differing in geographical origin and host insect were investigated. Highest protease activity was observed during 4–8 days of culture incubation. Pr1 and Pr2 activity was investigated in various media containing different carbon and nitrogen source to evaluate the induction mechanism of these enzymes. Basal levels of Pr1 and Pr2 activity were observed in minimal medium suggesting constitutive production. Casein (1%) as an exogenous protein supplement was not able to induce significant release of Pr1 and Pr2 enzymes, whereas high levels of activity were observed in the medium containing colloidal chitin (2%) as sole carbon and nitrogen source. The pH, ammonia and oxalic acid production in in vitro conditions was also investigated and the alteration in pH for protease production was not significant in the different media used except for the medium containing casein (1%) as a supplement.

/pdf/cuticle-degrading-proteases-produced-by-metarhizium-35ybeh24m5.pdf

Cuticle-Degrading Proteases Produced by Metarhizium anisopliae and Their Induction in Different Media

Beauveria bassiana a natural soil borne insect pathogen is being used effectively these days in integrated pest management system. Foliar application of these fungi is quite satisfactory as it invades its host by adhering to insect cuticles through the formation of penetration structures called appresoria, which produces various extracellular enzymes, including chitinase that causes the insect cuticle breaching. Although many investigations have been done in this regard, only a little is known about the induction and repression mechanism of this hydrolytic enzyme. This report illustrates the effect of two carbon sources; colloidal chitin and dextrose and a nitrogen source, yeast extract on the chitinase production of seventeen B. bassiana isolates. The chitinase activity varied among the isolates and the different media studied. A high enzymatic activity was observed in the medium with colloidal chitin as a sole source of carbon followed by the medium containing an extra nitrogen source, yeast extract. Exochitinase activity and the chitinase activity gel were also determined for the isolates showing high chitinase enzyme activity. An array of chitinase isozymes were observed on chitinase activity gel with a common 70 kDa enzyme for all the isolates. Keywords : Beauveria bassiana , induction, colloidal chitin, chitinase, exochitinase.

/pdf/effects-of-carbon-and-nitrogen-sources-on-the-induction-and-4kxacx5k0y.pdf

Effects of carbon and nitrogen sources on the induction and repression of chitinase enzyme from Beauveria bassiana isolates

Concentrations of fungal spores constitute a significant amount in bioaerosol depending on geographical regions and seasonal variations. Mycotoxin producing spores have adverse effects on humans. The aim of the study was to evaluate the prevalent species of airborne fungi in the indoor environment of the Shyambazar Metro-Railway Station, Kolkata, India. This area is below the ground level and fully surrounded, with constant movement of commuters. It is warm and humid with temperature and humidity ranges of 26.8 to 35.9°C and 50 to 88.3% respectively. Air sample was collected for four months within the interval of two weeks by means of gravitational settling method via Petri dishes with Potato Dextrose Agar (PDA) culture media. Those fungi colonies that formed after an incubation period of 3 to 5 days at 25 to 28°C were determined on the basis of micro and macro morphological characteristics. In this investigation, among fourteen spore types,Aspergillus niger was the most prevalent fungal genera followed by Aspergillus flavus andPenicillium sp. In addition, five sterile types and one unidentified species were also detected. The variation in the number of fungal colony was observed after every two weeks, in the summer months. The results of this investigation appeared to be quite significant for taking corrective measures.

	 

	Key words: Bioaerosol, aeromycoflora, mycotoxin, fungal spore, metro-railway station.

https://www.academicjournals.org/article/article1380787128_Ghosh et al.pdf

Identification and distribution of aeromycoflora in the indoor environment of Shyambazar Metro-Railway Station, Kolkata, India

Beauveria bassiana is an insect pathogenic fungus and is currently being exploited as an effective commercial mycoinsecticide. Solid state fermentation is the most efficient way to mass produce B. bassiana conidiospores on solid substrates. Statistical optimization strategy was adopted to maximize the conidia production through solid state fermentation. Four substrates viz., rice (polished), crushed sorghum, wheat bran and rice bran at variable moisture content and yeast extract concentration were used. A full factorial central composite design was used to design the experiment and response surface method was used to study the optimal parameters required for large scale production. Optimization of the two most important factors like moisture content and yeast extract concentration at varied levels conferred best conidial yield of 28.8 × 109 /gm for the mixed substrate rice + wheat bran at 35% moisture content and 1.5% yeast extract concentration.

	 

	Key words: Beauveria bassiana, central composite design, conidiospores, response surface methodology, solid state fermentation.

Priyanka Dhar

Papers

Production of cuticle - degrading proteases by Beauveria bassiana and their induction in different media

Cuticle-Degrading Proteases Produced by Metarhizium anisopliae and Their Induction in Different Media

Effects of carbon and nitrogen sources on the induction and repression of chitinase enzyme from Beauveria bassiana isolates

Identification and distribution of aeromycoflora in the indoor environment of Shyambazar Metro-Railway Station, Kolkata, India

Response surface methodology for optimizing process parameters for the mass production of Beauveria bassiana conidiospores