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At least 109 records · Page 6Linked to original sources
PubMed1971

The metabolism of cyclohexanol by Nocardia globerula CL1.

1. Nocardia globerula CL1, isolated by enrichment on cyclohexanol and grown with it as carbon source, oxidized it with a Q(o2) of 39mul/h per mg dry wt. and the overall consumption of 2.2mumol of oxygen/mol of substrate. Cyclohexanone, 2-hydroxycyclohexan-1-one dimer and cyclohexane-1,2-dione were oxidized with Q(o2) values similar to that for cyclohexanol whereas in-caprolactone and 6-hydroxycaproate were oxidized very slowly and adipate not all. 2. Disrupted cell suspensions could not be shown to catalyse the conversion of cyclohexanol into cyclohexanone. 3. A cyclohexanol-induced cyclohexanone oxygenase (specific activity 0.55mumol of NADPH oxidized/min per mg of protein) catalysed the consumption of 1mol of NADPH and 1mol of O(2) in the presence of 1mol of cyclohexanone. NADPH oxidation did not occur under anaerobic conditions. The only detected reaction product with 25000g supernatant was 6-hydroxycaproate. 4. Extracts of cyclohexanol-grown cells contained a lactone hydrolase (specific activity 15.6mumol hydrolysed/min per mg of protein), which converted in-caprolactone into 6-hydroxycaproate. 5. Incubation of 6-hydroxycaproate with 25000g supernatant in the presence of NAD(+) resulted in NAD(+) reduction under anaerobic conditions, oxygen consumption under aerobic conditions and the conversion of 6-hydroxycaproate into adipate. 6. Cyclohexanone oxygenase fractions devoid of in-caprolactone hydrolase catalysed the stoicheiometric formation of in-caprolactone from cyclohexanone in the presence of excess of NADPH. 7. The reaction sequence for the oxidation of cyclohexanone by N. globerula CL1 is: cyclohexanol --> cyclohexanone --> in-caprolactone --> 6-hydroxycaproate --> adipate. 8. It is suggested that the adipate may be further dissimilated by beta-oxidation.

Alcohols↗
PubMed1982

Temporary and selective anosmia in tiger salamanders (Ambystoma tigrinum) caused by chemical treatment of the olfactory epithelium.

Tiger salamanders (Ambystoma tigrinum) were trained to respond to two dissimilar odorants (i.e., cyclohexanone, dimethyl disulfide) but not to a third odorant (n-butanol). When the training criterion was met, the animals were anesthetized and given nasal lavages of saline or odorants in saline. Lavage with cyclohexanone decreased responding to cyclohexanone but not dimethyl disulfide, and vice-versa, in later behavioral tests. Likewise, ethyl acetoacetate lavage produced selective response decrements to cyclohexanone. Lavage with n-butanol had no effect on responding to presentations of either cyclohexanone or dimethyl disulfide. The effects of lavage increased with increasing odorant concentration. Thus, lavage with 0.05 M cyclohexanone or ethyl acetoacetate produced more persistent response decrements than lavage with 0.01 M concentrations of either odorant. Such results are consistent with several testable interpretations, including the possibility the response decrements could reflect the nature of odorant-receptor interactions.

1-Butanol↗
PubMed1986

Odor specificity of the enhanced neural response following early odor experience in rats.

The enhanced neural response in the olfactory bulbs of rat pups following early olfactory experience is specific to the familiar odor. Pups were exposed daily to either peppermint or cyclohexanone odor for the first 18 postnatal days. On day 19, peppermint-familiar pups exposed to peppermint had significantly higher [14C]2-deoxyglucose (2-DG) uptake in a focal glomerular area compared with the response to peppermint by cyclohexanone-familiar pups. We also found that cyclohexanone-experienced pups had a subsequent enhanced response to cyclohexanone odor in glomerular areas medial and caudal to those responding to peppermint. None of the 2-DG uptake differences were attributable to respiration differences between the groups during any part of the odor test.

Animals↗
PubMed1977

The metabolism of trans-cyclohexan-1,2-diol by an Acinetobacter species.

1. Acinetobacter TD63 was one of some thirty organisms isolated by elective culture with trans-cyclohexan-1,2-diol as sole source of carbon. The great majority of these isolates displayed the same growth spectrum as Nocardia globerula CL1 and Acinetobacter NCIB 9871 being capable of utilizing trans-cyclohexan-1,2-diol, 2-hydroxycyclohexan-1-one, cyclohexanol, cyclohexanone,1-oxa-2oxocycloheptane and adipate and were assumed to use well described metabolic pathways. 2. Acinetobacter TD63 was distinctive in being incapable of growth with cyclohexanol, cyclohexanone or 1-oxa-2-oxocycloheptane and because of this it was hoped that it would display an alternative pathway for the oxidation of trans-cyclohexan-1,2-diol. 3. Studies with cell extracts have shown the presence of inducible dehydrogenase for the conversion of trans-cyclohexan-1,2-diol to 2-hydroxycyclohexan-1-one and cyclohexan-1,2-dione and of 6-oxohexanoate to adipate. These enzymes are linked into a metabolic sequence by the action of a monooxygenase of broad specificity but efficiently capable of converting 2-hydroxy-cyclohexan-1-one into the lactone 1-oxa-2-oxo-7-hydroxycycloheptane that spontaneously rearranges to yield 6-oxohexanoate. 4. An enzyme capable of attacking cyclohexan-1,2-dione (mono-enol) in the absence of an electron donor or oxygen has also been detected. Evidence has been presented indicating that this enzyme catalyses a keto-enol tautomerization between cyclohexan-1,2-dione (mono-enol) and cyclohexan-1,2-dione (mono-hydrate) and is not involved in the pathway of ring cleavage. 5. The failure of Acinetobacter TD63 to grow with cyclohexanol, cyclohexanone or 1-oxa-2-oxocycloheptane is due not to this organism possessing a distinctive metabolic sequence but to a narrow inducer specificity coupled with an inability to form a lactone hydrolase enabling it to cleave the stable 1-oxa-2-oxocycloheptane which is an intermediate in the established pathway of cyclohexanol and cyclohexanone oxidation.

Acinetobacter↗
PubMed1988

Anaerobic metabolism of cyclohexanol by denitrifying bacteria.

Three strains of denitrifying bacteria were anaerobically enriched and isolated from oxic or anoxic habitats with cyclohexanol or cyclohexanone as sole electron donor and carbon source and with nitrate as electron acceptor. The bacteria were facultatively anaerobic, Gram-negative and metabolism was strictly oxidative with molecular oxygen, nitrate, or nitrite as terminal electron acceptor. Cyclohexanol and cyclohexanone were degraded both anaerobically and aerobically. Aromatic compounds were oxidized in the presence of molecular oxygen only. One of the bacterial strains was further characterized. During anaerobic cyclohexanol degradation approximately 40% of the substrate was oxidized to phenol, which accumulated as dead-endproduct in the growth medium; 60% of cyclohexanol was completely oxidized to CO2 and assimilated, respectively. In addition to phenol formation, transient accumulation of cyclohexanone, 2-cyclohexenone and 1,3-cyclohexanedione was observed. Based on these findings we propose a pathway for anaerobic cyclohexanol degradation involving these intermediates.

Anaerobiosis↗