Enhanced Toxicity of Bacillus thuringiensis Subspecies kurstaki and aizawai to Black Cutworm Larvae (Lepidoptera: Noctuidae) With Bacillus sp. NFD2 and Pseudomonas sp. FNFD1

A bioacumulação de metais por microrganismos se deve principalmente a fenômenos de superfície, ocorrendo adsorção, de forma estequiométrica, com os radicais aniônicos dos envoltórios celulares, seguido ou não de precipitação dos metais. Para estudar condicionantes da sorção de metais por bactérias vivas, quantificou-se o Cu2+ e Mn2+ retirados por um Bacillus sp. e uma Pseudomonas sp., isolados da rizosfera de trigo, de uma solução de cloreto dos metais, determinando-se a quantidade de metal restante no sobrenadante, após centrifugação. Usou-se delineamento experimental inteiramente casualizado, com três repetições. Ensaiaram-se efeito dos teores de Cu2+ e Mn2+, do pH e do tempo de crescimento bacteriano. O Bacillus sorveu mais Cu2+ e Mn2+ do que Pseudomonas. em todas as concentrações desses metais. A sorção de Cu2+ por ambas as bactérias apresentou maiores incrementos do que Mn2+ com aumento dos teores desses metais na solução. A alteração do pH 5,0 para 3,0 diminuiu a sorção dos dois metais. Com o tempo de cultivo de 90 horas a Pseudomonas apresentou maior sorção de cobre e de manganês do que no tempo de 16 horas. Os resultados obtidos assemelham-se aos fenômenos de troca de cátions em colóides.

Download Full-text

Spodoptera frugiperda (Lepidoptera: Noctuidae) Strains from Northern Argentina: Esterases, Profiles, and Susceptibility to Bacillus thuringiensis (Bacillales: Bacillaceae)

Florida Entomologist ◽

10.1653/024.102.0209 ◽

2019 ◽

Vol 102 (2) ◽

pp. 347 ◽

Cited By ~ 3

Author(s):

Flavia del Valle Loto ◽

Alfonso Emanuel Carrizo ◽

Cintia Mariana Romero ◽

Mario Domingo Baigorí ◽

Licia María Pera

Keyword(s):

Bacillus Thuringiensis ◽

Spodoptera Frugiperda ◽

Lepidoptera Noctuidae

Download Full-text

Characterization and Lipolytic Activity of Bacteria Isolates from Freshwater Clam (Mercenaria Mercenaria) in Bayelsa State, Nigeria

10.47363/jftns/2020(2)109 ◽

2020 ◽

pp. 1-4

Author(s):

Opara C N ◽

◽

Anumudu C K ◽

Keyword(s):

Protein Content ◽

Culture Media ◽

Lipolytic Activity ◽

Cell Mass ◽

Mercenaria Mercenaria ◽

Total Protein Content ◽

Growth Media ◽

Pseudomonas Sp ◽

Bacillus Sp ◽

Freshwater Clam

Lipases form an important group of relevant enzymes which have applications in various fields including; food, pharmaceutical, detergent, textile and cosmetic industries. Lipases can be produced from diverse sources including microorganisms. This study evaluated the potential of bacteria isolates from fresh-water clam Mercenaria Mercenaria to produce lipolytic enzymes. Ten samples of Clam (Mercenaria Mercenaria) were screened for the presence of lipase producing bacteria using classical culture methods. Eleven bacteria species were obtained, of which six (Actinomyces sp., E. coli, Bacillus sp., Pseudomonas sp., Clostridium sp. and Klebsiella sp.) produced lipases that had lipolytic activity in breaking down olive oil used in media supplementation. The best culture media and conditions for optimal production of lipases was studied and it was shown that supplementation of growth media with 2% dextrose at neutral pH gave the greatest yield of lipases when lipase producing isolates were grown in shake flasks. Measurement of biomass by culture and turbidimetric methods indicates that the highest cell mass was recorded by Pseudomonas sp at 7.8 x 105 CFU/ml, closely followed by Actinomyces sp. and Bacillus sp., at 6.2 x 105 CFU/ml and 5.3 x 105 respectively. The produced lipases were partially purified by precipitating with ammonium sulphate followed by dialysis. The total protein content of produced lipases was evaluated by the Lowry’s method, showing that estimated protein content followed the same trend as cell biomass with the highest recorded by Pseudomonas sp. at 1.53mg/ml, followed by Actinomyces sp. and Bacillus sp. at 1.47mg/ml and 1.32mg/ml respectively. The results obtained in this study shows that isolates obtained from freshwater clam can produce potent lipases which can be employed for industrial, food and other diverse uses

Download Full-text