ALBERT

Notes: Abstract Growth of Methanobacterium formicicum strain MF was studied in pH-stat batch cultures and formatelimited chemostat cultures. The maxium rate of methanogenesis from formate occurred at pH 7.6 and 43°C and the maximum specific growth rate constant (μm) was 0.08 h-1. The K s and maximum growth yield (Y s max ) were 3.5 mM formate and 1.4 (g dry wt) mol01 formate respectively, and the maintenance coefficient (m) was calculated as 6.8 mmol formate (g dry wt)-1 h-1. The efficiency of electron transport phosphorylation during formate metabolism assuming Y ATP of 10.5 g mol-1 was about 20%. The specific activities of hydrogenase and formate dehydrogenase increased slightly with dilution rate.

Notes: Summary The clearance of chlordiazepoxide from the systemic circulation was studied in 20 subjects which included 15 patients with alcoholic hepatitis and 5 normal volunteers. The half-life for the appearance of the drug in the systemic circulation was found to increase exponentially with age (r=0.73, P〈0.0005) and was independent of the presence of alcoholic hepatitis. The metabolic clearance of chlordiazepoxide was significantly lower in the patients than in the normal subjects (7.6 compared to 13.8 ml/kg-h, P〈0.005). Linear regression analysis revealed a significant correlation between clearance and albumin (r=0.77, P〈0.00005). However, the predictive value of this relationship was shown to be minimal. Multiple regression analysis produced only a slight improvement in the correlation when both albumin and lactate dehydrogenase were used as variables (r=0.83, P〈0.00005). In six of the patients, a second clearance study was conducted three weeks following their initial one. All repeat subjects showed improvement both clinically and as reflected by their laboratory tests for liver injury, but there was not a significant change in their clearance of chlordiazepoxide. Multiple regression analysis of the clearance data on the initial and repeat subjects showed a significant correlation between clearance and the variables age, albumin, and lactate dehydrogenase (r=0.91, P〈0.0025). This relationship suggests that over a short period of time (where age can be considered constant) changes in albumin and lactate dehydrogenase could be potentially useful in predicting clearance changes in a single individual.

Notes: Summary The infusion of dibutyryl-cyclic AMP into the dog renal artery in vivo leads to diuresis, natriuresis and glucosuria. Addition of the nucleotide to the incubation medium bathing dog renal cortex slices in vitro causes inhibition of p-amino-hippurate accumulation and stimulation of glycine and β-methyl-glucoside transport. The results are interpreted in terms of the development of a blood-lumen flux of sodium and water in the renal proximal tubule, analogous to that seen in the intestine.

Notes: Summary Leaf litter breakdown and fine root production, including exudation, are two major influences upon carbon and nitrogen mineralization rates in forest soil. Sieving and root removal experiments were used to examine their effects. Although carbon mineralization rates declined in smaller particle size fractions of forest litter, this trend largely disappeared when results were calculated on an ash-free basis. Nitrogen mineralization by contrast, was greatest in smaller fractions. Much of the variation in carbon mineralization rates appeared to be associated with fine roots. A rapid initial exponential decay phase noted in laboratory respiration studies was probably associated with disappearance of available carbon in the form of root exudates and/or the microorganisms dependent on them. Clear cutting caused a marked reduction in the size of available carbon pools, reflecting decreased root exudation and rhizosphere activity. A model of mineralization is proposed which represents the available and humified carbon pools.

Notes: Abstract Seven diversity indices were calculated for each of fifty-eight microcosm communities. All fifty-eight communities were initiated from equal density inoculations of fourteen algal species. Each microcosm developed in one of six controlled experimental environments; the environments differing only in their temporal patterns of disturbance. Five linear discriminating techniques were used to evaluate the diversity index most useful for discriminating between these environments. The Shannon-Wiener index was best according to two of the discriminating methodologies and second best using the other techniques. Evenness was best when the Shannon-Wiener index was second best and vice versa.

Notes: Abstract Computer recognition of prospective areas through the processing of digital exploration data can be effective if the statistical tests for the determination of the prospects are pertinent to the presence of the desired mineral. Where exploration involves the application of polynomial trend analysis to structure contour maps in the search for petroleum and natural gas, standard analysis of variance tests may not indicate the best exploration maps. Variance tests may be completely invalid where isolated dips and clustered samples cause the surfaces generated by some of the most common trend programs to oscillate, creating a false impression of variance. On the other hand, tests that directly compare the position of residual features with areas of known production consistently indicate the best map for the determination of new prospects. They are simple to apply and appear to offer the most opportunity for the automatic recognition of prospective areas.

Notes: Summary The PMN is exquisitely designed to combat invading micro-organisms. The relationship between structure and function is nowhere more evident than in this cell type. The elaborate biochemical machinery which the PMNs possess for killing ingested micro-organisms works as a highly integrated system, with each step occurring in sequence and at a particular site. In the past decade or so it has become apparent that the Klebanoff system (myeloperoxidase-halide-H2O2) and possibly other active O2 species as well, play an important role in the bactericidal activity of PMNs. Application of cytochemical techniques for oxidative enzymes and for end-products of oxidative reactions has localized the sites within the phagocytosing or stimulated PMN at which these various components of the cidal systems are active and generated. In this fashion, biochemical data have been not only confirmed, but in several instances, the cytochemical approach has led the way in extending our knowledge and thinking regarding PMN metabolism and cidal functions. In our laboratory we have studied the bactericidal machinery of PMNs by cytochemical means. We have established, at the ultrastructural level, that the myeloperoxidase-containing azurophil granules fuse with the phagosome membrane and empty their contents into the phagosome (Baehneret al., 1969). We have shown that H2O2 is generated within the phagosome (Briggset al., 1975b). This established that the myeloperoxidase-H2O2 system could work within the phagosome, since both of these components are present following phagocytosis. We determined that H2O2 could be detected on the cell surface and within the phagosome following phagocytic stimulation of NADH oxidase activity (Briggset al., 1975a). The cell surface localization of H2O2 was an important finding since the phagosome membrane is derived from the plasmalemma. Thus internalization of the plasmalemma, with components capable of generating H2O2, can explain the presence of H2O2 within the phagosome. We have also shown that when PMNs are treated with non-particulate stimuli of the respiratory burst, similar results are found, that is, H2O2 is present on the cell surface and within vesicles, which are presumed to be of surface origin (Badweyet al., 1980). We have shown that D-amino acid oxidase, another enzyme capable of generating H2O2 is cytochemically demonstrable and that it can utilize cell wall components of ingested bacteria as substrates for enzyme activity (Robinsonet al., 1978). The PMNs from CGD patients do not kill certain bacteria. This inability to kill bacteria is related to the low levels of H2O2 produced during phagocytosis. Using the cerium reactioon we determined that PMN from CGD patients produce little cytochemically detectable H2O2 and that what little is present is restricted to the phagosome (Briggset al., 1977). Some PMNs contain other oxidases which are capable of generating H2O2 and O 2 − from O2 consumed during phagocytosis. The guinea-pig PMN (but not human) has an unusual aldehyde oxidase. Cytochemically the aldehyde oxidase activity is restricted to the phagosome (Robinsonet al., 1979). We have also developed a method for localization of sites of O 2 − production following stimulation. In phorbol myristate acetate-stimulated PMNs, reaction product for O 2 − is present within surface-derived vesicles, and in some cases, on the cell surface. Cytochemical detection of enzymes and products of enzymatic activity (H2O2 and O 2 − ) associated with stimulation of the respiratory burst in PMN has thus provided further evidence for the importance of active oxygen species in phagocytosis. Furthermore, the site-specific information obtained from cytochemistry has provided an important link in understanding the structure-function interplay associated with phagocytosis in PMNs. It should be realized, however, that the cytochemical methods we have utilized detect in most instances the end product of an enzymatic reaction (for example, H2O2) and not the site of the enzyme itself. This is important, for instance in the case of H2O2, because this entity appears to begenerated on the surface of the plasmalemma or on the luminal surface of the phagosomal membrane. However, the enzyme responsible may well be situated on the cytoplasmic side of these membranes, and the generation of the H2O2 may involve an electron shuttle across the membrane. Such a mechanism may involve cytochrome and quinone compounds as carriers (Segal & Jones, 1979; Millardet al., 1979). Experiments are now being designed to localize the sites of the enzymesper se by immunocytochemistry. This approach should help resolve these important questions.