Production of mycelium and blastospores of

Hirsutella sp. was grown in four liquid media containing either casamino acids, corn steep liquor, collagen peptone or casein peptone. These media were inoculated with a 7 day-old culture of mycelia and blastospores of Hirsutella sp. and the cultures incubated with shaking at 250 rpm at 26°C. The media containing corn steep liquor, casamino acids or collagen peptone produced abundant mycelium, varying from 64 to 76.3 mg/ml at different fermentation days, whereas the medium containing casein peptone produced less biomass. Additionally, the casamino acids and collagen peptone media showed similar biomass values, as well as blastospore counts after 14 fermentation days, without significant differences between the two media. The highest number of blastospores produced was 3.8 × 107 blastospores/ml using medium with casamino acids. This medium, as well as that with collagen peptone gave suitable results for the preparation of an inoculum for the production of conidia in solid medium.Key words: Hirsutella, liquid media, fermentation, blastospores, microbial control, mass propagation

Producción, diseño y evaluación de formulados de Bacillus thuringiensis serovar. israelensis contra larvas de Aedes aegypti

Se realizó la producción de Bacillus thuringiensis var. israelensis 225 en dos nuevos medios de cultivo solubles a base de (1) jarabe de maíz, sólidos de remojo del maíz y extracto de levadura, y otro (2) a base de harina de semilla de girasol y sacarosa, así como uno de referencia (3) con harina de soya, sólidos de remojo del maíz, melaza y sales minerales. Los extractos insecticidas producidos en los diferentes medios mostraron diferencias en el rendimiento, donde se obtuvo mayor rendimiento (18.9 g/L) en el medio de referencia, sin embargo, este extracto resultó menos tóxico que el obtenido en el nuevo medio soluble 1, que mostró la menor CL₅₀ de 0.4712 mg/l a las 48 horas postaplicación. Los formulados granulados resultaron más efectivos que las tabletas contra larvas de Aedes aegypti, donde se mostró que los ingredientes de formulación proporcionaron protección a la toxina contra la degradación por la luz UV.The production of bioinsecticide of Bacillus thuringiensis var. israelensis 225 was carried on two new culture media based soluble (1) corn syrup, maize steep solids and yeast extract, and another (2) based on sunflower seed meal and sucrose, as well as one reference medium (3) with soybean meal, maize steep solids, molasses and minerals. Insecticidal extracts produced in the different media showed differences in yield, where higher yield (18.9 g / L) was obtained in the reference medium, however this extract was less toxic than that obtained in the new soluble medium 1, which showed lower LC₅₀ of 0.4712 mg / L at 48 hours post-application. The granular formulations were more effective than the tablets against Aedes aegypti larvae, where it was shown that the formulation ingredients provided protection to the toxin against degradation by uv light

Producción de unidades infectivas de Isaria fumosorosea (Hypocreales : Cordycipitaceae ) a partir de aislados nativos del noreste de México mediante 3 estrategias de propagación

El objetivo del presente estudio fue evaluar la producción de blastosporas y conidios de diferentes aislados nativos de México del hongo entomopatógeno Isaria fumosorosea y de una cepa de colección mediante diferentes técnicas de propagación. En la producción de blastosporas se utilizaron 2 medios de cultivo líquidos (sumergidos), uno a base de casaminoácidos y el otro a base de peptona de colágeno como fuentes de nitrógeno, con glucosa como fuente de carbono en ambos. Para la producción de conidios, los hongos se cultivaron en agar papa dextrosa, a partir de esos cultivos se prepararon suspensiones de 1 × 106 conidios/ml para inocular matraces con caldo dextrosa Sabouraud, para iniciar así la fase líquida del cultivo bifásico, denominado también precultivo. Posteriormente con el precultivo y las suspensiones de conidios se inocularon bolsas con granos de arroz, que se incubaron durante 14 días para el cultivo bifásico y para la fermentación sólida, respectivamente. El aislado HIB-23 fue el que logró la más elevada concentración de blastosporas obtenida en el cultivo sumergido: 4,90 × 108 blastosporas/ml en el medio casaminoácidos ; y en el medio con peptona de colágeno se obtuvieron 2,15 × 108 blastosporas/ml. La máxima producción de conidios en fermentación sólida la logró la cepa Pfr-612 (1,58 × 109 conidios/g), mientras que la máxima en cultivo bifásico correspondió al aislado HIB-30 (9,00 × 106 conidios/g). La fermentación sólida resultó ser el método más efectivo, con un promedio de 1,09 × 109 conidios/g, mientras que el cultivo bifásico fue el menos efectivo, con un promedio de 2,76 × 106 conidios/g. Para la producción de blastosporas en los medios sumergidos no se obtuvo diferencia significativa algun

Effect of Ascophyllum nodosum extracts on the growth, yield and antioxidant capacity of Haematococcus pluvialis carotenoids

Recent research has shown that the use of biological extracts, which contain a wide variety of nutrients and phytohormones are potentially useful in the production of plants of agricultural importance. Seaweed extracts are particularly rich in minerals and micronutrients necessary for the growth of microalgae. The effect of three commercial extracts of Ascophyllum nodosum as plant growth inducers (Stimplex®, Acadian Soils® and Liquid Seaweed Concentrate®), provided by Acadian Sea Plants Ltd., were evaluated in relation to the growth and production of biomass and carotenoids in Haematococcus pluvialis. The results were evaluated by one-way ANOVA and post-hoc analysis utilizing Tukey's test with a significance level of 95% (α= 0.05). The reference medium used was the Bold basal medium, to which 250 ppm of each extract was added. The Stimplex® extract had an increase of 22.79% in cell density and 17% in dry matter, higher than the control culture. The content of carotenoids and antioxidant capacity, respectively, with Stimplex® was 30.05% and 141.76% higher than the control culture

Conidia production of Isaria fumosorosea (Hypocreales: Cordycipitaceae) in organic substrates through two propagation techniques

In the last decades, the use of entomopathogenic fungi for the control of pest insects has increased globally, however a key step to achieve the successful application of fungal propagules as biocontrol agents depends of various factors, inoculum production being one of the essential stages for these microorganisms to be used in pest management programs. The objective of this study was to evaluate the production of conidia by solid fermentation and biphasic culture in different sporulation matrices for four native isolates and a strain of Isaria fumosorosea that have been shown potential for the control of various insects at the laboratory level. The experimental design was completely randomized, two propagation methods were used with six treatments and ten repetitions per treatment; the data were analyzed using an analysis of variance and the means were compared using the Tukey test (p≤ 0.05). In the production by solid fermentation the minimum value of 5.30 × 105 conidia g-1 was registered with the pericarp of peanut and the maximum of 2.35 × 107 conidia g-1 in the corn grain; in the biphasic culture the minimum of 7.60 × 105 conidia g-1 was observed in birdseed and the maximum of 2.07 × 107 conidia g-1 in rice. The differences were significant (p ≤ 0.05) in the production by method and by substrate, in solid fermentation 6.84 × 106 conidia g-1 and in biphasic culture 8.85 × 106 conidia g-1. In the production by substrate, the rice showed 1.75 × 107 conidia g-1 and the lesser canary seed concentration (7.80 × 105 conidia g-1). The average production per isolate and / or strain was of the order of 106 and significant difference was registered (p ≤ 0.05) among the fungi, the isolate HIB-9 showed concentration in average higher in the production (7.90 × 106 conidia g-1) and the isolated HIB-19 was the least effective, with only 1.08 × 106 conidia g-1. The results obtained show marked differences between the isolates with respect to their capacity to use the different substrates used as propagation media to obtain conidia of I. fumosorosea

Producción de conidios en sustratos sólidos y mutación del hongo entomopatógeno Hirsutella citriformis mediante metanosulfonato de etilo

El Huanglonging (HLB) está ocasionando grandes pérdidas en cítricos causada por la bacteria Candidatus liberibacter y transmitida por el insecto Diaphorina citri. Una de las alternativas es el control del vector usando hongos entomopatógenos como Hirsutella citriformis, el cual presenta algunas desventajas como su lento crecimiento y baja conidiación. En este trabajo se determinaron como objetivos, obtener alta producción de conidios en varios sustratos vegetales, así como conocer la concentración y tiempos de exposición de un agente mutagénico como el metanosulfonato de etilo (MSE) sobre la cepa silvestre necesarios para generar cepas mutantes al azar que mostraran características mejoradas. H. citriformis fue cultivada en dos sustratos vegetales arroz y avena y sometida a varias concentraciones de MSE y diferentes tiempos. Se obtuvo un total de 104 colonias mutantes las cuales se caracterizaron y seleccionaron en base a su velocidad de crecimiento radial, producción de conidios y germinación respecto a la cepa silvestre. Cuatro cepas mutantes fueron seleccionadas para futuros estudios.Huanglonging disease (HLB) is causing large losses in citrus which is caused by the bacterium Candidatus liberibacter and transmitted by the insect Diaphorina citri. One alternative is the control of vector using entomopathogenic fungi as Hirsutella citriformis, however this fungus has some drawbacks as slow growth and low conidiation. Therefore, in this work objectives such as obtaining higher production of conidia in various plant substrates as well as to determine the concentration and exposure times of a mutagenic agent such as ethyl methane sulfonate (EMS) on the wild strain to generate mutant strains at random that showed improved features were performed. A total of 104 mutant colonies were obtained which were characterized and selected based on their rate of radial growth, conidia production and germination compared to the wild strain, this analysis allowed us to select four mutant strains for future studies including bioassays against the insect vector