An anaerobic glove box constructed of clear flexible vinyl plastic is described. It is sufficiently inexpensive and simple in operation to be used not only in research but also in a clinical laboratory by technicians without special training. Conventional bacteriological techniques may be used inside the glove box for culturing and transferring anaerobic bacteria. The box may be heated to 37 C and thus serve as an anaerobic incubator as well, permitting inspection of cultures at any time. Media may be prepared and agar plates may be poured on the laboratory bench in the conventional manner. An overlay of trace amounts of palladium black catalyst over plated agar media reduces the medium to an oxidation-reduction (O-R) potential of - 300 mv within 2 days after introduction into the glove box. In spite of its greater simplicity, the system matched or excelled the roll tube method with respect to all parameters tested, including O-R potential obtainable in the media, O2 concentration in the gas phase, and efficiency in isolating anaerobic bacteria from the mouse cecum. Comparative studies indicate that the conventional anaerobic jar method was inadequate for the isolation of strict anaerobes from human gingival specimens and from the mouse cecum. This was due to the exposure of specimens and media to air during plating on the open laboratory bench. Anaerobic jars were adequate for maintaining the proper conditions for growth of anaerobic bacteria once these had been established in the glove box. Images

Isolation of anaerobic bacteria from human gingiva and mouse cecum by means of a simplified glove box procedure.

When the supply of oxygen to the interior of living cells is reduced to a rate insufficient for their current metabolic needs for oxygen, then various cellular oxidation-reduction systems must shift toward a more reduced state. Thus, as the oxygen tension falls the \"oxidation potential\" (\"Eh\") decreases (1, 2), (the rate of decrease being a complex and variable function of Po2 and also of the rate of energy utilization), and the various redox systems shift toward their reduced forms in a sequence determined by their inherent redox characteristics (1), cytochrome oxidase, the cytochromes and their dependent systems, flavoproteins and diphosphopyridine nucleotide (DPN). The lowest potential in the \"carrier\" system is that of DPN, which is the final electron donator and functions also in the \"metabolic\" oxidative systems; the rates of the oxidations of energy metabolism are not affected until DPN is affected. When the oxidative potential in the hypoxic cell has diminished to the level of the potentials of the \"metabolic\" systems, the first of these DPN-coupled systems to become reversed will be the one of potential closest to that of DPN: DPNH2, the lactic dehydrogenase (LDH) system.

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Relationships of pyruvate and lactate during anaerobic metabolism. ii. exercise and formation of o2-debt

Redox mediators promote electron transfer in microbial fuel cells. The reduction of a range of redox mediators by bacteria was studied in some detail in order to identify effective mediator—organism combinations. Rates of reduction of mediator dyes by bacteria were measured spectrophotometrically at 30°C under anaerobic conditions for standardised concentrations of organism, substrate and dye. The kinetics of dye reduction showed two general patterns: a simple, exponential curve or a complex curve with an initial linear rate followed by a faster exponential rate of reduction. Dye-reduction rates were greater than rates of oxygen consumption (QO2) for several combinations of organism and redox dye. Thionine, brilliant cresyl blue, methylene blue and benzyl viologen were tested in combination with Alcaligenes eutrophus, Azotobacter chroococcum, Bacillus subtilis, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa and Pseudomonas putida, using glucose and succinate as substrates. Rates of reduction of alizarin brilliant blue, 2,6-dichlorophenolindophenol, gallocyanine, new methylene blue, N,N-dimethyl-disulphonated thionine, phenazine ethosulphate, resorufin, safranine-O, phenothiazinone and toluidine blue-O were also measured with Pr. vulgaris only. For E. coli, both QO2 and the rate of thionine reduction increased with increasing temperature in the range 25 to 37°C, but for Pr. vulgaris thionine reduction rates did not correlate with temperature in this way. Dye-reduction rates and QO2 for Az. chroococcum were dependent on the components of the washing solution and/or the temperature at which cell suspensions were prepared. The results are discussed in relation to the use of these dyes as electron-transfer mediators in microbial fuel cells.

Electron-transfer coupling in microbial fuel cells: 1. comparison of redox-mediator reduction rates and respiratory rates of bacteria

Natural resistance to infection, which does not depend on antibiotics, is a powerful protective mechanism common to all mankind that has been responsible for the survival of our species during countless millennia in the past The normal functioning of this complex system of phagocytic cells and tissue fluids is entirely dependent on an extremely low level of free ionic iron (10(-18) M) in tissue fluids This low-iron environment is maintained by the unsaturated iron-binding proteins transferrin and lactoferrin, which depend on well-oxygenated tissues, where a relatively high oxidation-reduction potential (Eh) and pH are essential for the binding of ferric iron Freely available iron is derived from iron overload, free haem compounds, or hypoxia in injured tissue leading to a fall in Eh and pH This can severely damage or abolish normal bactericidal mechanisms in tissue fluids leading to overwhelming growth of bacteria or fungi The challenge for clinical medicine is to reduce or eliminate the presence of freely available iron in clinical disease In injured or hypoxic tissue, treatment with hyperbaric oxygen might prove very useful by increasing tissue oxygenation and restoring normal bactericidal mechanisms in tissue fluids, which would be of huge benefit to the patient

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Otto H. Müller

Papers

Oxidation-reduction potentials in bacteriology and biochemistry

Polarography in medicine, biochemistry, and pharmacy

The polarographic method of analysis. II. Apparatus

The polarographic method of analysis. V. Applications

The development of polarography and polarographic instruments