A study of 2,4,6-trinitrotoluene inhibition of benzo[a]pyrene uptake and activation in a microbial mutagenicity assay.

A number of in vitro and in vivo studies have determined that binary and complex mixtures may interact to produce a toxicity that could not be predicted based on the individual chemicals. The present study was conducted with a binary mixture of model compounds to investigate possible interactions affecting their mutagenicity. The compounds included Benzo[a]pyrene (BAP), a polycyclic aromatic hydrocarbon that is an indirect-acting mutagen of great environmental concern, and 2,4,6-Trinitrotoluene (TNT), a nitro-aromatic compound that is a direct-acting mutagen frequently found as a soil contaminant at munitions sites.

Ultrastructure of the Host-Pathogen Relationship in Entomosporium Leaf Spot Disease of Photinia.

Entomosporium mespili appears to be a hemibiotroph on infected Photinia leaves. This fungal pathogen produced distinctive haustoria in living host cells in young lesions. Each haustorium possessed a long slender neck with a single septum and an enlarged distal body that contained a single nucleus.

Cyclic AMP induces rapid increases in gap junction permeability and changes in the cellular distribution of connexin43.

The rapid effects of cAMP on gap junction-mediated intercellular communication were examined in several cell types which express different levels of the gap junction protein, connexin43 (Cx43), including immortalized rat hepatocyte and granulosa cells, bovine coronary venular endothelial cells, primary rat myometrial and equine uterine epithelial cells. Functional analysis of changes in junctional communication induced by 8-bromo-cAMP was monitored by a fluorescence recovery after photobleaching assay in subconfluent cultures in the presence or absence of 1.0 mM 1-octanol (an agent which uncouples cells by closing gap junction channels).

Cellular effects of misscheduled brlA, abaA, and wetA expression in Aspergillus nidulans.

Asexual sporulation in the fungus Aspergillus nidulans is controlled, in part, by a central regulatory pathway composed of the brlA, abaA, and wetA genes. The coding region of each of these genes was fused, in frame, to the threonine-inducible alcohol dehydrogenase promotor then stably incorporated into the A. nidulans genome at the argB locus.

Rodletless, a new Aspergillus developmental mutant induced by directed gene inactivation.

The Aspergillus nidulans CAN41 transcription unit is activated by the brlA regulatory gene early during development of the asexual reproductive apparatus, the conidiophore. Disruption of CAN41 results in a novel mutant phenotype in which conidiophore cells and spores lack an external wall layer, the rodlet layer, making them less hydrophobic than in the wild type and leading to inefficient spore dispersal. The rodletless mutation defines a new locus on chromosome III, rodA.