Molecular cloning and characterization of a cDNA encoding cytochrome c oxidase subunit Va from the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae).

A cDNA encoding subunit Va of cytochrome c oxidase (EC 1.9.3.1) was cloned and characterized from a lesser grain borer (Rhyzopertha dominica) cDNA library. The complete cDNA consists of 693-bp and contains an open reading frame of 450-bp that encodes 150 amino acid residues. The sequence includes a 28-bp putative N-terminal and a 122-bp putative mature protein. The estimated molecular weight and pI for the predicted mature protein are 13,962 and 4.60, respectively. The cDNA-deduced amino acid sequence of the mature protein shows 73% identity to that of a corresponding subunit of African malaria mosquito (Anopheles gambiae) and 59% identity to that of the fruit fly (Drosophila melanogaster). In addition, 31% of all amino acid residues are conserved among six different animal species. Evolutionary distance analysis suggests that cytochrome c oxidase subunit Va from R. dominica is most similar to the corresponding subunit from the malaria mosquito. Northern analysis revealed a single 4.9-kb transcript that is much larger than that found in mammalian species.

Use of Optical Sorting to Detect Wheat Kernels Infected with Tilletia indica.

Wheat infected with Tilletia indica is subject to international regulation by 78 countries, and U.S. economic losses could exceed $1 billion if T. indica was found throughout major wheat-producing regions and caused wheat exports to be halted. Samples are currently manually inspected for the presence of kernels with Karnal bunt as part of routine survey methods. This visual inspection of all seed in a sample can result in harvest delays due to long inspection times and missed kernels due to inspector fatigue. A high-speed sorter was tested to determine if infected kernels could be rapidly removed from 1,800-g wheat samples. When the sorter removed about 8% or more of the sample, the reject portion contained 100% of the bunted kernels. Concentrating the bunted kernels in a smaller sample size will reduce sample inspection time and should reduce inspection errors. One high-speed sorter can process up to 8,800 kg/h; thus, bunted kernels can be rapidly removed from samples or large lots. Each sample was sorted in less than 1 min. This technology provides the wheat industry with a tool to rapidly inspect samples to aid in regulating Karnal bunt, and to remove bunted grains from seed wheat and wheat destined for food or feed use.