[Neurological complications of infectious mononucleosis in 3 patients]. / Neurologische complicaties van mononucleosis infectiosa bij 3 patiënten.

Neurological complications of infectious mononucleosis were seen in three patients, a boy aged 18 months and two women aged 70 and 51 years respectively: a Bell's palsy, polyradiculitis and transverse myelitis. In a patient with acute neurological symptoms without indications of any other cause, infectious mononucleosis should be considered.

Electron transport-linked proton translocation at nitrite reduction in Campylobacter sputorum subspecies bubulus.

Campylobacter sputorum subspecies bubulus contains a membrane-bound nitrite reductase which catalyses the six-electron reduction of nitrite to ammonia. Formate and L-lactate are used as hydrogen donors. Cells of C. sputorum grown with nitrate or nitrite contain cytochromes of the b- and c-type and a carbon monoxide-binding cytochrome c. In addition, a special membrane-bound carbon monoxide-binding pigment is found. Nitrite reduction with formate or L-lactate as a hydrogen donor is strongly inhibited by 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO). Nitrite reduction by bacterial suspensions with lactate as a hydrogen donor is strongly inhibited by carbonylcyanide-m-chlorophenylhydrazone (CCCP) whereas nitrite reduction with formate as a hydrogen donor is not inhibited at all. Leads to H+/O values and leads to H+/NO-2 values were measured with ascorbate + N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), formate (in the absence and presence of carbonic anhydrase) and L-lactate as a hydrogen donor. The results are summarized in a scheme for electron transport from formate or lactate to oxygen or nitrite which shows a periplasmic orientation of formate dehydrogenase and nitrite reductase and a cytoplasmic orientation of lactate dehydrogenase and oxygen reduction, and which shows proton translocation with a leads to H+/2e value of 2.0. The leads to H+/O and leads to H+/NO-2 values predicted by this scheme are in good agreement with the experimental values.

Oxygen consumption by Campylobacter sputorum subspecies Bubulus with formate as substrate.

The kinetics of oxygen utilization by the microaerophile Campylobacter sputorium subspecies bubulus was studied. With formate as substrate two enzyme systems were found to be responsible for electron transfer between formate and oxygen. In the case of lactate oxidation one enzyme system could account for the activity measured. One of the formate-oxidizing systems possessed a high affinity for oxygen [Km(O2) = approx. 4 microM O2]. From inhibitor studies it was concluded that a respiratory chain was involved in its activity. Respiration by this system must be responsible for proton translocation and electron transport-linked phosphorylation at formate oxidation. The other enzyme system had an extremely low affinity for oxygen [Km (O2) = approx. 1 mM O2]. It was tentatively identified as the H2O2-producing formate oxidase previously found in C. sputorum. The H2O2 production by this enzyme is implicated in an explantation of the microaerophilic nature of C. sputorum. Sensitivity of formate dehydrogenase to H2O2 was demonstrated. The influence of the formate concentration on aerobic formate oxidation was determined. The pH- and temperature dependencies of oxygen uptake with formate as substrate were examined at air-saturation and at a low dissolved oxygen tension.

Microaerophily.

Objections to previous definitions of "anaerobiosis" and "micro-aerophily" are discussed, and a new definition of "micro-aerophily" is proposed. A survey of physiological characteristics of the micro-aerophilic bacterium Campylobacter sputorum spp. bubulus is given, and the concept of "micro-aerophily" is illustrated by the results of a study on the oxygen metabolism and oxygen sensitivity of this bacterium.

Superoxide dismutase and hydrogen peroxide formation in Campylobacter sputorum subspecies bubulus.

Cell-free extracts of Campylobacter sputorum subspecies bubulus contained superoxide dismutase. The enzyme was located in the cytoplasmic fraction and insensitive to cyanide. After centrifuging a cell-free extract at 144000 x g for 1.5 h the total activity in the supernatant fraction was threefold higher than in the crude cell-free extract. The pellet fraction thus obtained was shown to have a lowering effect on superoxide dismutase activities from different sources in the assay method used here. C. sputorum responded to a raised oxygen tension in the culture by an increase in the superoxide dismutase activity. The ability to produce superoxide anion radicals (O2-.) during oxidation of formate and lactate was demonstrated. Furthermore C. sputorum was found to produce H2O2 while oxidizing formate. In experiments in which the reduction of cytochrome c by formate was followed, step-wise kinetics were observed. One of the steady states then obtained was attributed to the oxidizing action of H2O2, because it was abolished by the addition of catalase and lengthened by H2O2 added in addition to H2O2 formed as a product of formate oxidation. An overall reaction for formate oxidation by C. sputorum is discussed.

The effect of different dissolved oxygen tensions on growth and enzyme activities of Campylobacter sputorum subspecies bubulus.

Campylobacter sputorum subspecies bubulus was grown in batch cultures in which the dissolved oxygen tension (d.o.t) was maintained at various constant levels. At a range of d.o.t. from 0.002 to 0.05 atm, which allowed good growth (mean generation time approximately 1.5 h), L-lactate was preferentially consumed before D-lactate. L-lactate oxidation was accompanied by equimolar acetate production during exponential growth. A value for YL-lactate (g dry weight bacteria per mol L-lactate) of 54 was determined. Net acetate production stopped when C. sputorum started to use D-lactate after consumption of L-lactate. When a culture growing exponentially at the expense of L-lactate was shifted from a d.o.t. of 0.02 atm to a d.o.t. of 0.15 atm, growth was impaired, and L-lactate consumption and corresponding acetate production diminished. This decrease correlated with a loss of lactate dehydrogenase activity after the shift. Campylobacter sputorum appeared to possess cytochromes of the b- and c-type and a carbon monoxide-binding pigment. Evidence is given that the principal site of oxygen damage is lactate dehydrogenase rather than the cytochrome chain.