A PCR Assay to Identify and Distinguish Single Juveniles of Meloidogyne hapla and M. chitwoodi.

Random amplified polymorphic DNA (RAPD) bands that distinguish Meloidogyne hapla and M. chitwoodi from each other, and from other root-knot nematode species, were identified using a series of random octamer primers. The species-specific amplified DNA fragments were cloned and sequenced, and then the sequences were used to design 20-mer primer pairs that specifically amplified a DNA fragment from each species.

The catalytic cysteine and histidine in the plant acyl-acyl carrier protein thioesterases.

The plant acyl-acyl carrier protein (acyl-ACP) thioesterases (TEs) play an essential role in chain termination during de novo fatty acid synthesis and are of biochemical interest because of their utilities in the genetic engineering of plant seed oils. Biochemical data have shown the possible involvement of an active-site cysteine and a histidine in catalysis, suggesting that these enzymes activate the hydrolysis of the thioester bond using the same basic catalytic machinery as those of proteases and lipases. To identify the cysteine and histidine residues that are critical in catalysis we substituted, in a 12:0 ACP TE (Uc FatB1), a conserved cysteine (Cys-320) to an Ala or a Ser, and three conserved histidines (His-140, His-285, and His-345) to an Ala or an Arg.