Characterization of glycerol nonutilizing and protoperithecial mutants ofNeurospora

Abstract

Mutants defective in polyol metabolism and/or in protoperithecial development were selected in Neurospora tetrasperma, a species in which protoperithecial development occurs at nonpermissively high temperature if certain polyols are used in lieu of sucrose as carbon source. Mutants selected for nonutilization of one of the four polyols tested, glycerol, mannitol, sorbitol, or xylitol, were usually found to be nonutilizers of the other three polyols as well. Mutants blocked at various stages of protoperithecial development complemented pairwise to produce more advanced developmental stages, usually mature protoperithecia and, when of opposite mating type, mature perithecia. About one-third of the mutants manifested both polyol auxotrophy and defective protoperithecial development upon initial isolation, but protoperithecial defectiveness in such mutants usually showed erratic segregation in crosses and/or instability to repeated vegetative transfer, whereas polyol auxotrophy usually did not and was, therefore, studied further. Two glycerol nonutilizing strains were introgressed into N. crassa to facilitate genetic analysis. One, glp-4, lacked both inducible and constitutive glycerol kinase and mapped to linkage group VI, between ad-1 and rib-1; the other, glp-5, lacked glyceraldehyde kinase and mapped to linkage group I, proximal to ad-9. Another mutant, gly-u(234), has been reported by other investigators to lack inducible glycerol kinase but to map to linkage group I, distal to ad-9.

Glycerol metabolism and transport in yeast and fungi: established knowledge and ambiguities

“…Moreover, the level of glycerate 3‐kinase was about twofold higher in the mutants compared with the wild type. As glycerol kinase activity is also detectable in N. crassa indicating the presence of the classical G3P pathway (Viswanath‐Reddy et al ., ), it has been suggested that the catabolic GA pathway, including the two sub‐pathways for the second part, might represent another route for glycerol catabolism in this organism. Although the GA catabolic pathway has not been described in yeasts so far, homologs of the enzyme catalyzing the first step in this pathway have been reported in S. cerevisiae (Gcy1 and Ypr1) as already mentioned above.…”

Tartronate Semialdehyde Reductase Defines a Novel Rate-Limiting Step in Assimilation and Bioconversion of Glycerol in Ustilago maydis

“…Currently, three glycerol metabolic pathways have been reported [24], one phosphorylative pathway [25], [26] and two oxidative pathways that are based on NAD(P) + -dependent glycerol dehydrogenases [27]. In this report, we have identified and characterized the first eukaryotic TSR and demonstrated its role in glycerol catabolism and production of glycolipids from glycerol (Figure 5, 6, S3, S4, Table 2).…”

Insights into an alternative pathway for glycerol metabolism in a glycerol kinase deficientPseudomonas putidaKT2440

“…Some facultative anaerobic bacteria such as Klebsiella aerogenes use the phosphorylation pathway under aerobic conditions, but can employ the oxidation pathway in the absence of oxygen (28). In some bacteria, it is also possible for glycerol to be oxidised to glyceraldehyde (29), which may then be converted to glycerate (30).…”