Phenotypic lag in macroconidia of N. crassa his-3\u3csup\u3e+\u3c/sup\u3e transsformants and its implication in estimation of nuclear ratios

A majority of prototrophic macroconidia of two of the three histidine transformants of Neurospora crassa tested required histidine for germination. This condition led to an underestimation of the proportion of his-3+ macroconidia in the samples and wronged the estimation of ratio of his-3+/ his-3 nuclei by direct plating method. To correctly estimate nuclear ratio, a sample of colonies from histidine-supplemented plating medium was transferred to histidine drop-out slants and the proportion of auxotrophic and prototrophic colonies was determined from their growth response. The amino acid requirement by prototrophic macroconidia was not specific, was limited to colony formation and was not due to low endogenous content of amino acids

Increase in germination and plating efficiency of Neurospora crassa microconidia by amino acid supplementation

A major difficulty that has limited the use of uninucleate microconidia in genetic research is their low and erratic germination. We found that the supplementation of sorbose plating medium by amino acids, notably aspartic acid and methionine, markedly improved germination and plating efficiency of microconidia of mcm and pe fl genotypes of N. crassa. The plating efficiency of mcm microconidia in amino acid supplemented medium was comparable to macroconidia

Theoretical development and critical analysis of burst frequency equations for passive valves on centrifugal microfluidic platforms

This paper presents a theoretical development and critical analysis of the burst frequency equations for capillary valves on a microfluidic compact disc (CD) platform. This analysis includes background on passive capillary valves and the governing models/equations that have been developed to date. The implicit assumptions and limitations of these models are discussed. The fluid meniscus dynamics before bursting is broken up into a multi-stage model and a more accurate version of the burst frequency equation for the capillary valves is proposed. The modified equations are used to evaluate the effects of various CD design parameters such as the hydraulic diameter, the height to width aspect ratio, and the opening wedge angle of the channel on the burst pressure.close