Effect of the dilution rate on microbial competition: r-strategist can win over k-strategist at low substrate concentration.

The conditions present in both in vitro and in vivo ecosystems determine the microbial population harbouring it. One commonly accepted theory is that a species with a high substrate affinity and low growth rate (k-strategist) will win the competition against a second species with a lower substrate affinity and higher growth rate (r-strategist) if both species are subjected to low substrate concentrations. In this study two nitrite oxidizing bacteria (NOB), Nitrospira defluvii (k-strategist) and Nitrobacter vulgaris (r-strategist), were cultivated in a continuous reactor systems.

Treatment of high-grade, high-stage prostate cancer with estramustine phosphate or diethylstilbestrol. A double-blind study. The SPCG-1 Study Group. Scandinavian Prostate Cancer Group.

Between 1984 and 1989, 197 patients with T1-4, NX, M1, G2-3 or G3 prostate cancer were randomized to treatment with 560 mg estramustine phosphate (EMP, Estracyt, Emcyt) or 3 mg diethylstilbestrol (DES) per day in a double blind study with stratification on presence or absence of cancer pain at start. A total of 194 patients were evaluated for efficacy of therapy. Time to progression (p = 0.

Oat mesophyll protoplasts: their response to various feeder cultures.

Oat (Avena sativa L.) mesophyll protoplasts were recently demonstrated to be capable of dedifferentiation, repeated divisions, and colony formation. Since the development of oat mesophyll protoplasts is decisively influenced by the nature of the used feeder culture (species, variety and concentration), we conducted a systematic study of this parameter.

Colony formation from mesophyll protoplasts of a cereal, oat.

Differentiated leaf cells of gramineous plants, among them the cereals with their immense importance for human nutrition, are considered extremely recalcitrant to, if not incapable of, reentering the cell cycle. This recalcitrance is related to the poor wound response of the monocots-in contrast to most dicots-and the difficulties encountered in monocot tissue culture. We report here the highly reproducible induction of sustained divisions at high frequency (up to 95%) and colony formation from mesophyll protoplasts of a cereal, oat, demonstrating that-contrary to most earlier evidence-mesophyll cells of a gramineous plant have not irreversibly lost their potential for cell division.

Cytogenetics of protoplast cultures of Brachycome dichromosomatica and Crepis capillaris and regeneration of plants.

Callus derived protoplasts of Brachycome dichromosomatica (2n=2x=4) and Crepis capillaris (2n=2x=6) have been regenerated into karyologically normal plants, i.e. plants without visible alterations of the diploid chromosome set.