A wide spectrum of antibacterial activity of secondary metabolites from Bacillus amyloliquefaciens ELI149 / Um amplo espectro de atividade antibacteriana dos metabólitos secundários de Bacillus amyloliquefaciens ELI149

A highly potent secondary metabolites-producing Bacillus strain was isolated from Mexican soil (Puebla State), together with other fifty strains. The fifty-one strains were subjected for metabolites extraction and evaluated as antibacterial against several bacteria. The active metabolites of these strains were extracted using amberlite XAD16 absorbent resin. The antibacterial activity of crude extracts of all strains was performed by disk diffusion method against some pathogenic gram positive and gram-negative bacteria. Among all Bacillus strains tested, the most potent strain ELI149 (NRB) was selected for molecular characterization. The nucleotide sequence of the 16S rRNA gene (1.5 Kb) of this strain evidenced a 94% similarity with Bacillus amyloliquefaciens strain IIHR-Ba-2, which showed the highest inhibition against the most bacteria probed even greater inhibition than the standard antibiotic. In conclusion, secondary metabolites extracted from Bacillus amyloliquefaciens strain are highly potent as antibiotic against the most bacteria probed. Identification of which metabolites extracted from amberlite are the responsible of the bacteria growth inhibition will be a challenge

Um altamente potent metabolitos secundários-produzindo tensão de Bacillus esteve isolada de terra mexicana (Puebla Estatal), junto com outras cinquenta tensões. As cinquenta e uma tensões estiveram submetidas para extracção de metabolitos e avaliado como antibacterial contra várias bactérias. Os metabolitos ativos destas tensões estiveram extraídos utilizando amberlite XAD16 resina absorbente. O antibacterial actividade dos extractos crus de todas as tensões esteve actuado por método de difusão do disco na contramão alguns a grama patogénica positivo e grama-bactérias negativas. Entre todas tensões de Bacillus provaram, a maioria de potent tensão ELI149 (NRB) esteve seleccionado para caracterização molecular. A sequência de nucleótido do 16S rRNA gene (1.5 Kb) desta tensão evidenced uma 94% semelhança com Bacillus amyloliquefaciens tensão IIHR-Ba-2, o qual mostrou a inibição mais alta na contramão as mais bactérias probed inclusive inibição maior que o antibiótico regular. Em conclusão, os metabolitos secundários extraíram de Bacillus amyloliquefaciens a tensão é altamente potent tão antibiótico na contramão as mais bactérias probed. Identificação do qual os metabolitos extraíram de amberlite é o responsável pela inibição de crescimento das bactérias será um repto.

Mannheimia haemolytica OmpP2-like is an amyloid-like protein, forms filaments, takes part in cell adhesion and is part of biofilms.

Mannheimia haemolytica causes respiratory disease in cattle. Amyloid proteins are a major component of biofilms; they aid in adhesion and confer resistance against several environmental insults. The amyloid protein curli is highly resistant to protease digestion and physical and chemical denaturation and binds Congo red (CR) dye. The purpose of this study was to characterize an approximately 50-kDa CR-binding amyloid-like protein (ALP) expressed by M. haemolytica. This protein resisted boiling and formic acid digestion and was recognized by a polyclonal anti-Escherichia coli curli serum, suggesting its relationship with amyloid proteins. Immunolabeling and transmission electron microscopy showed that antibodies bound long, thin fibers attached to the bacterial surface. Mass spectrometry analysis indicated that these fibers are M. haemolytica OmpP2-like proteins. The purified protein formed filaments in vitro, and antiserum against it reacted positively with biofilms. An in silico analysis of its amino acid sequence indicated it has auto-aggregation properties and eight amyloid peptides. Rabbit polyclonal antibodies generated against this ALP diminished the adhesion of ATCC 31612 and BA1 M. haemolytica strains to A549 human epithelial cells, indicating its participation in cell adhesion. ALP expressed by M. haemolytica may be important in its pathogenicity and ability to form biofilms.

Gallibacterium elongation factor-Tu possesses amyloid-like protein characteristics, participates in cell adhesion, and is present in biofilms.

Gallibacterium, which is a bacterial pathogen in chickens, can form biofilms. Amyloid proteins present in biofilms bind Congo red dye. The aim of this study was to characterize the cell-surface amyloid-like protein expressed in biofilms formed by Gallibacterium strains and determine the relationship between this protein and curli, which is an amyloid protein that is commonly expressed by members of the Enterobacteriaceae family. The presence of amyloid-like proteins in outer membrane protein samples from three strains of G. anatis and one strain of Gallibacterium genomospecies 2 was evaluated. A protein identified as elongation factor-Tu (EF-Tu) by mass spectrometric analysis and in silico analysis was obtained from the G. anatis strain F149T. This protein bound Congo red dye, cross-reacted with anti-curli polyclonal serum, exhibited polymerizing properties and was present in biofilms. This protein also reacted with pooled serum from chickens that were experimentally infected with G. anatis, indicating the in vivo immunogenicity of this protein. The recombinant EF-Tu purified protein, which was prepared from G. anatis 12656-12, polymerizes under in vitro conditions, forms filaments and interacts with fibronectin and fibrinogen, all of which suggest that this protein functions as an adhesin. In summary, EF-Tu from G. anatis presents amyloid characteristics, is present in biofilms and could be relevant for the pathogenesis of G. anatis.

Growth of hydroxyapatite on the cellular membrane of the bacterium Bacillus thuringiensis for the preparation of hybrid biomaterials.

This study aimed to grow hydroxyapatite (HAp) crystals on the cellular wall of the Gram-positive bacterium Bacillus thuringiensis using a bio-mimetic method. Several strains were phenotypically and genotypically characterized using multilocus sequence typing (MLST) gene markers to differentiate the strains and confirm the identity of the isolated species to guarantee that the selected species was not harmful to human health or the environment. Three of the analyzed strains were selected because they exhibited the best nucleation and growth of HAp on the bacterial surface. This innovative method to grow HAp crystals on a cellular membrane helps to elucidate the mechanisms by which osseous tissue is formed in nature. The optimum concentration for the simulated physiological fluid (SPF) was 1.5×. The hybrid materials were characterized by optical microscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR).

Genetic manipulation in Bacillus thuringiensis for strain improvement.

Bacillus thuringiensis (Bt) has been used as a biopesticide in agriculture, forestry and mosquito control because of its advantages of specific toxicity against target insects, lack of polluting residues and safety to non-target organisms. The insecticidal properties of this bacterium are due to insecticidal proteins produced during sporulation. Despite these ecological benefits, the use of Bt biopesticides has lagged behind the synthetic chemicals. Genetic improvement of Bt natural strains, in particular Bt recombination, offers a promising means of improving efficacy and cost-effectiveness of Bt-based bioinsecticide products to develop new biotechnological applications.