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Enzymes and metabolites associated with mitigation of paraquat toxicity were compared in two paraquat-tolerant mutants and a sensitive wild-type strain of the fern Ceratopteris richardii Brongn. In 21-day-old gametophytes, the specific activities of superoxide dismutase, catalase, peroxidase, glutathione reductase, dehydroascorbate reductase, and ascorbate peroxidase showed no differences that would explain mutant tolerance. Constitutive levels of ascorbate and glutathione also did not differ significantly in the three strains. An experiment testing the inducibility of paraquat tolerance revealed no change in the dose response of mutant or wild type gametophytes after exposure to sublethal concentrations of the herbicide. Uptake of paraquat by whole gametophytes was also equivalent in mutants and wild type. These data suggest that the physiological basis for tolerance in these mutants, unlike several other tolerant biotypes reported, does not lie in the oxygen radical scavenging system, in an inducible stress response, or in a block to whole-plant uptake.

A double-blind, placebo-controlled, crossover-therapy study was carried out using intraindividual comparisons on 18 type II diabetics. All patients were secondary drug failure patients and had been on insulin-glibenclamide combination therapy for periods of 1-14 months. On the last day of each of the 2-week-treatment periods (insulin-glibenclamide [verum phase] versus insulin-placebo [placebo phase]) the patients received a standard breakfast equivalent to 100 g glucose. Medication was given 30 minutes before the standard breakfast. The blood glucose level during insulin-glibenclamide therapy was 35-45 mg/dl below that during insulin-placebo treatment at all time points investigated. Correspondingly, the glucose excretion was reduced by about 40% during the verum phase. beta-Hydroxybutyrate in serum and urine and glycosylated haemoglobin (HbA1) measurements made during the verum phase were also significantly lower. As expected, the insulin level in serum showed no change. In contrast, C peptide concentrations were significantly raised by 15-40% during the verum phase. Combination therapy with insulin and glibenclamide produced therefore a marked improvement in the metabolic status of C peptide-positive patients classified as secondary drug failure patients to oral therapy.

A whole plant selection system using the haploid gametophyte generation of the fern Ceratopteris richardii has been developed to select for mutations that confer resistance or tolerance to various selection pressures. The expression of the mutations can be analyzed and characterized in both the haploid gametophyte and diploid sporophyte generations. Genetic analyses are facilitated by the fern's rapid life cycle and the ease of manipulating the gametophyte generation. Selection for tolerance to the herbicide paraquat has yielded two mutants which have an increased tolerance to the herbicide in both the gametophyte and sporophyte generations. Both mutants exhibit single nuclear gene inheritance patterns and appear to be closely linked or allelic.

Large volumes of eyespot granules were isolated from homogenates of Euglena gracilis Klebs var. bacillaris Pringsheim by flotation centrifugation in a Beckman Ti-15 zonal rotor, and were further purified by centrifugation in a swinging bucket rotor. Examination with the electron microscope showed the eyespot granules to be free from other cellular material. Freezing had no apparent effect on the structure or on the absorption properties of the eyespots. Absorption spectra of pure fractions of eyespot granules free of chloroplast contamination showed the previously reported curves in the range of 360 to 520 nanometers, as well as a peak at 660 to 675 nanometers. The procedure for the large scale isolation of eyespot granules from Euglena gracilis is compared with other methods which have employed conventional centrifugation, and the significance of the use of zonal rotors for isolating large quantities of pure eyespot granules is discussed.