Scanning Electron Microscopic Studies of Candida albicans

A scanning electron microscopic study of selected morphological stages of Candida albicans is presented. Stages represented are budding yeast cells, mycelial-like forms, chlamydospores, germ tube formation, and an unusual rough cell type.     

Some experiences in the estimation of parameters in non-linear differential equations

The author describes a procedure developed by himself and his colleagues for obtaining estimates of the parameters of rate equations, together with information about confidence regions for the estimates. The program has been used successfully for processing results from the chemical engineering industry, with highly non-linear model systems, particularly since temperature was a variable, and the "rate constants" were non-linear combinations of other constants. In biochemical situations, in which investigations are almost always at constant temperature, the non-linearity should not be so extreme, and the procedure may well be capable of dealing with more than 5 to 7 parameters for which it is recommended.     

The action of plant growth retardants on terpenoid biosynthesis

Summary The plant growth retardants (2-chloroethyl)-trimethylammonium chloride (CCC) and 2-isopropyl-4-(trimethylammoniumchloride)-5-methylphenyl-piperidine-1-carboxylate (AMO-1618) inhibit gibberellic-acid biosynthesis inFusarium moniliforme at the cyclisation of geranylgeraniol to (-)-kaurene, causing an accumulation of geranylgeraniol. The two inhibitors have no effect on the biosynthesis of ergosterol inF. moniliforme or sitosterol in barley seedlings.     

Lead Poisoning in Gurkha Soldiers in Hong Kong

Investigation of an outbreak of lead-poisoning in 121 Gurkha soldiers showed that this was due to the contamination of chilli powder (cayenne pepper), a constituent of curry powder, with lead chromate. Comprehensive systems of food sampling are needed in developing communities.     

Acridine Sensitivity of Bacteriophage T2H in Escherichia coli

Normally acridine-sensitive, Escherichia coli-T2H complexes are rendered acridine-resistant if the infecting bacteriophage mutant is either pr or q. If these pr or q mutants are treated to produce sensitive revertants, one obtains a mutation at any of several dye-sensitizing (ds) sites in the early enzyme region of the T2 map. The ds mutants are nonspecific suppressors because they reduce the resistance of complexes containing either pr or q to proflavine. The ds mutants are not identical in action, since some make pr or q sensitive to proflavine and quinacrine, and others, to proflavine alone. Two ds mutants have r to r(+) mutation patterns which differ, depending upon whether or not the ds is coupled with r7 (an rII mutant). The mutation patterns of r(+) to r are the same for both ds mutants and for wild type. We suggest that dye sensitization may consist of alterations of early enzymes so as to produce slightly different forms of deoxyribonucleic acid which are in turn dyesensitive.