AtMYB41 acts as a dual-function transcription factor that regulates the formation of lipids in an organ- and development-dependent manner.

The plant cuticle controls non-stomatal water loss and can serve as a barrier against biotic agents, whereas the heteropolymer suberin and its associated waxes are deposited constitutively at specific cell wall locations. While several transcription factors controlling cuticle formation have been identified, those involved in the transcriptional regulation of suberin biosynthesis remain poorly characterized. The major goal of this study was to further analyse the function of the R2R3-Myeloblastosis (MYB) transcription factor AtMYB41 in formation of the cuticle, suberin, and suberin-associated waxes throughout plant development. For functional analysis, the organ-specific expression pattern of AtMYB41 was analysed and Atmyb41ge alleles were generated using the CRISPR/Cas9 system. These were investigated for root growth and water permeability upon stress. In addition, the fatty acid, wax, cutin, and suberin monomer composition of different organs was evaluated by gas chromatography. The characterization of Atmyb41ge mutants revealed that AtMYB41 negatively regulates the production of cuticular lipids and fatty acid biosynthesis in leaves and seeds, respectively. Remarkably, biochemical analyses indicate that AtMYB41 also positively regulates the formation of cuticular waxes in stems of Arabidopsis thaliana. Overall, these results suggest that the AtMYB41 acts as a negative regulator of cuticle and fatty acid biosynthesis in leaves and seeds, respectively, but also as a positive regulator of wax production in A. thaliana stems.

Positive inotropic action of Solanaceae glycoalkaloids.

Six glycoalkaloids and one aglycone were tested for cardiotonic activities and compared with K-strophanthoside by use of the isolated frog heart. The decreasing order of potency was as follows: K-strophanthoside greater than tomatine greater than alpha-chaconine=alpha-solanine greater than demissine=commersonine greater than beta-chaconine greater than solanidine. Cardiotonic activity was directly related to the number of sugars in the molecule in which the glycoalkaloids had a common aglycone. On the other hand, glycoalkaloids with dissimilar aglycones, but with identical sugars, such as tomatine and demissine, differed significantly with respect to cardiotonic potency. Apparently, therefore, the cardiotonic activity of glycoalkaloids on the frog heart is determined by the nature of the aglycone and the number of sugars and not by the kinds of sugars or their stereochemical configuration.

The isolation of Neisseria species from unusual sites.

The isolation of N. gonorrhoeae from the pharynx of four patients and N. meningitidis from the genital tract of six patients is described. Sexual transmission seemed the most likely means of acquiring these organisms. Three out of four patients harbouring gonococci in the pharynx were asymptomatic, while four of six patients with genital meningococci were symptom-free. The isolation of meningococci from the genital tract coincided with an unusually high incidence of meningococcal disease in the community.

Antibiotic sensitivities of Neisseria gonorrhoeae in the Toronto area.

The antibiotic sensitivity pattern of 3872 isolates of N. gonorrhoeae tested in Toronto from 1969 to 1973 is reviewed. An increase in resistance to both penicillin and tetracycline was noted up to 1971, but no further increase has occurred since then. Ninety-seven percent of 135 patients with "sensitive" strains (inhibited by 0.3 U/ml of penicillin and/or 0.5 mug/ml of tetracycline) were cured by either 8 g of tetracycline or 5,000,000 U of penicillin, whereas only 59% of 58 patients with "resistant" strains (requiring 1.0 U/ml of penicillin and/or 2.0 mug/ml of tetracycline for inhibition) were cured by the same dosage. Spectinomycin appears to be an acceptable alternative therapy. Maximum doses of the chosen drug are recommended in the hope of retarding further spread of more resistant organisms.