Serial determination of lung volume in small animals by nitrogen washout

This report describes the design of an apparatus and the procedures used to serially measure the total lung capacity and the functional residual capacity of small animals utilizing the N2-washout technique. The calibration data indicate that the technique is accurate to within 1 ml and has a variance of less than 5%. The in vivo lung volume measurements of rats were validated by comparing them with values obtained with a water-displacement technique; the means were within 0.3 ml. Examples of the precision and changes in lung volume of animals during studies are included to demonstrate the reliability and usefulness of the technique.     

Polishing the craft of genetic diversity creation in directed evolution

Genetic diversity creation is a core technology in directed evolution where a high quality mutant library is crucial to its success. Owing to its importance, the technology in genetic diversity creation has seen rapid development over the years and its application has diversified into other fields of scientific research. The advances in molecular cloning and mutagenesis since 2008 were reviewed. Specifically, new cloning techniques were classified based on their principles of complementary overhangs, homologous sequences, overlapping PCR and megaprimers and the advantages, drawbacks and performances of these methods were highlighted. New mutagenesis methods developed for random mutagenesis, focused mutagenesis and DNA recombination were surveyed. The technical requirements of these methods and the mutational spectra were compared and discussed with references to commonly used techniques. The trends of mutant library preparation were summarised. Challenges in genetic diversity creation were discussed with emphases on creating “smart” libraries, controlling the mutagenesis spectrum and specific challenges in each group of mutagenesis methods. An outline of the wider applications of genetic diversity creation includes genome engineering, viral evolution, metagenomics and a study of protein functions. The review ends with an outlook for genetic diversity creation and the prospective developments that can have future impact in this field.     

Microplate well coverage mixing using superhydrophobic contact

Two important challenges in microplate instrumentation are to achieve full well sample coverage and complete mixing. An effective approach of using superhydrophobic rods to accomplish these challenges is reported here. Experiments conducted showed that analytes above 50μl could be made to completely cover the bottom of 96-well standard and transparency microplates. Complete mixing was accomplished by moving the rod parallel to the well bottom while contacting the liquid. The approach is simple and controlled, and it minimizes the problems of spillage and cross-contamination. It works with analytes with varied volumes and of different viscosities present in each well of the microplate.     

Chromoblastomycosis in Malaysia

Nine cases of histologically diagnosed Chromoblastomycosis are reported from Malaysia. All the patients were males and ranged in age from 56 to 65 years. The duration of symptoms varied from 5 months to 13 years. All the lesions were noted in the lower limbs. Malignancy was suspected clinically in 5 cases. The diagnosis was established by finding characteristic brown muriform cells in the tissue sections.