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MECHANISM OF TOXICITY AND RESISTANCE TO D‐MANNOSE AND CERTAIN DERIVATIVES IN SPECIES OF THE GENUS CHLORELLA BEIJ. 1 2
Author(s) -
Gross Rudolf E.
Publication year - 1968
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1968.tb04688.x
Subject(s) - biology , mannose , strain (injury) , biochemistry , hexose , chlorella , heterotroph , algae , enzyme , bacteria , botany , genetics , anatomy
SUMMARYd ‐Mannose and related derivatives, e.g., d ‐glucosa‐mine and 2‐deoxy‐ < d ‐glucose, blocked autotrophic and heterotrophic growth of several species of the genus Chlorella. Manometric studies showed differences in the effects of these compounds on substrate‐induced O 2 uptake, indicating different modes of action.In a clonal culture, shaken in the light, mannose produced a lag phase of 7 days during which only ca. 0.05% of the cells continued to grow. From, these cells a resistant strain was isolated. Prolonged incubation in glucose media in darkness brought about a reversion to the sensitive condition. These metabolic shifts could not be explained on the basis of adaptation or nuclear gene mutation because of the permanency and high frequency of the resistant cells. The mechanism was suggested to be cytoplasmically controlled. The shift in sensitivity to the inhibitors was considered a reproducible characteristic of certain species.In contrast to the normal, rnannose‐sensitive strain of C. infusionum var. acetophila, cells of a resistant strain carried a gelatinous envelope. The resistant strain utilized glucosamine as a source of nitrogen, but lost the capacity to use sugars for dark growth. This was reflected in drastic reductions in glucose and mannose uptake. The hexokinase activities in cell extracts were equivalent for both strains. The resistant strain did not accumulate hexose‐6‐phos‐phates and showed an increased phosphatase activity at an alkaline pH.