Expression and characterization of Aspergillus thermostable phytases in Pichia pastoris.

Two thermostable phytases were identified from Thai isolates of Aspergillus japonicus BCC18313 (TR86) and Aspergillus niger BCC18081 (TR170). Both genes of 1404 bp length, coding for putative phytases of 468 amino acid residues, were cloned and transferred into Pichia pastoris. The recombinant phytases, r-PhyA86 and r-PhyA170, were expressed as active extracellular, glycosylated proteins with activities of 140 and 100 U mL(-1), respectively.

Cys31, Cys47, and Cys195 in BinA are essential for toxicity of a binary toxin from Bacillus sphaericus.

The mosquito larvicidal binary toxin produced by Bacillus sphaericus is composed of 2 proteins called BinA and BinB. While BinB acts as specificity determinant, BinA is expected to bind to BinB, translocates into cytosol, and exerts its activity via an unknown mechanism. To study the role of cysteine in BinA, 3 cysteine residues were substituted by alanine and serine.

Amino acid substitutions in alphaA and alphaC of Cyt2Aa2 alter hemolytic activity and mosquito-larvicidal specificity.

Cyt2Aa2 produced by Bacillus thuringiensis subsp. darmstadiensis exhibits in vitro cytolytic activity against broad range of cells but shows specific in vivo toxicity against larvae of Dipteran insects. To investigate the role of amino acids in alphaA and alphaC of this toxin, 3 single-point mutants (A61C, S108C and V109A) were generated.

Co-expression of Bacillus thuringiensis Cry4Ba and Cyt2Aa2 in Escherichia coli revealed high synergism against Aedes aegypti and Culex quinquefasciatus larvae.

Cry4Ba is a delta-endotoxin produced by Bacillus thuringiensis subsp. israelensis and Cyt2Aa2 is a cytolytic delta-endotoxin produced by B. thuringiensis subsp.

Cloning and characterization of a mosquito larvicidal toxin produced during vegetative stage of Bacillus sphaericus 2297.

The mosquitocidal toxin 1 (mtx1) gene from genomic DNA of B. sphaericus strain 2297 was cloned and expressed in E. coli.

Efficient expression of the mosquito larvicidal binary toxin gene from Bacillus sphaericus in Escherichia coli.

The binary toxin gene encoding BinA (42 kDa) and BinB (51 kDa) from Bacillus sphaericus strain 2297 was cloned and expressed in E. coli. Low expression level was found when both proteins were expressed from a single operon.