An evolutionary comparison of Acinetobacter calcoaceticus trpF with trpF genes of several organisms

The deduced amino acid sequence of Acinetobacter calcoaceticus N-(5'-phosphoribosyl) anthranilate isomerase (PRAI), which is coded by trpF, was compared with TrpF of Caulobacter crescentus, Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae, Neurospora crassa, and Aspergillus nidulans. Sixty percent of identical or similar amino acids were located in alpha/beta TIM (triose-phosphate isomerase) barrels and in residues important in substrate binding and catalysis. In addition, the analysis of trpF genes presented here supports a model by which fusion between separate trpC and trpF genes arose in some cases by in-frame deletions.     

N2-Succinylornithine in ornithine catabolism of Pseudomonas aeruginosa

Most Pseudomonas aeruginosa PAO mutants which were unable to utilize l-arginine as the sole carbon and nitrogen source (aru mutants) under aerobic conditions were also affected in l-ornithine utilization. These aru mutants were impaired in one or several enzymes involved in the conversion of N²-succinylornithine to glutamate and succinate, indicating that the latter steps of the arginine succinyltransferase pathway can be used for ornithine catabolism. Addition of aminooxyacetate, an inhibitor of the N²-succinylornithine 5-aminotransferase, to resting cells of P. aeruginosa in ornithine medium led to the accumulation of N²-succinylornithine. In crude extracts of P. aeruginosa an ornithine succinyltransferase (l-ornithine:succinyl-CoA N²-succinyltransferase) activity could be detected. An aru mutant having reduced arginine succinyltransferase activity also had correspondingly low levels of ornithine succinyltransferase. Thus, in P. aeruginosa, these two activities might be due to the same enzyme, which initiates aerobic arginine and ornithine catabolism.Abbreviations OAT ornithine 5-aminotransferase - SOAT N²-succinylornithine 5-aminotransferase - Oru ornithine utilization - Aru arginine utilization     

Induction of transforming growth factor-alpha in activated human alveolar macrophages

The early monocyte infiltration observed in normal wound repair and in a number of pathologic processes precedes the epithelial and connective tissue proliferative responses, suggesting that the monocyte/macrophage may be an important source of growth factors for these tissues. In culture, activated macrophages secrete growth factors active on fibroblasts, smooth muscle, endothelium, and epithelium. This report demonstrates that activated human alveolar macrophages express the gene for transforming growth factor-alpha (TGF-alpha) in an inducible manner and secrete a factor into the culture medium that is functionally and immunologically identical to TGF-alpha. Two different molecular species of TGF-alpha activity (approximately 8,500-12,000 and 28,500 daltons) are identified in macrophage-conditioned medium. These observations establish the macrophage as a diploid human cell capable of synthesizing and secreting TGF-alpha. The activated macrophage therefore represents a cellular source of a mitogenic factor that is potentially important in epithelial proliferation and repair.     

Tetracycline production byStreptomyces aureofaciens: the time lag of production

Summary The exact time course of phosphate consumption in a tetracycline production byStreptomyces aureofaciens has been determined. The data have been compared with model simulations according to a model proposed by Votruba et al. (1984). This led to a revision of his equation for the rate of phosphate consumption and to the proposal that phosphate is consumed proportionally to the growth rate. In contradiction to the model simulations it was found that the length of the time lag of the production is independent of the initial phosphate concentration. While the model explains the time lag through inhibition of the production by phosphate, the measured data show that there must be another or an additional reason for the lag. Simultaneously with the start of the production the organism changes from an organic substrate to ammonia as nitrogen source.All experiments have been carried out in a bubble column of 651 working volume as fed batch fermentation. An autoanalyzer and a HPLC was coupled to the reactor for automatic measurement of phosphate, ammonia, sucrose and products in short intervals. Composition of the outlet gas, pH, pO₂, temperature and weight of the substrate flasks were monitored on-line.     

Isolation of highly multidrug-resistant P388 cells from drug-sensitive P388/S cells by flow cytometric cell sorting

To investigate the spontaneous frequency of occurrence of stable multidrug-resistant cells in a population of drug-sensitive cells, we exposed drug sensitive P388/S cells to daunorubicin (dnr) for 1 h, then used fluorescence-activated cell sorting based on intracellular dnr fluorescence to isolate cells within P388/S having different intracellular content of drug. One of the sort windows chosen (low dnr content sort window) isolated only P388/S cells with intracellular drug content equal to or less than that of the known multidrug-resistant subline P388/adr. This sort window constituted approximately 3% of P388/S cells with lowest dnr content. By such a procedure we were able, on one of seven attempts, to isolate and cultivate stable, highly multidrug-resistant cells (comparable to that of P388/adr) from the P388/S cells obtained from the low dnr-content sort window. Net growth of cells in culture was observed 15-20 days after sorting, indicating that of the P388/S cells collected from the low dnr-content sort window, very few were actually highly drug-resistant. On no occasion could resistant cells be cultivated from cells sorted from P388/S with higher dnr content, as would be expected if mutation to a multidrug-resistant phenotype had occurred as a result of exposure to drug. The resistant cells isolated from P388/S by sorting (called P388/LoSort) displayed low intracellular accumulation of dnr that was enhanced by verapamil, were cross-resistant to vincristine and actinomycin-D, and distinct from P388/S, possessed a 150- to 160-kD membrane species identified by Vinca alkaloid photoaffinity labeling.(ABSTRACT TRUNCATED AT 250 WORDS)     

Galanin-Like Immunoreactivity Is Unchanged in Alzheimer''s Disease and Parkinson''s Disease Dementia Cerebral Cortex

Galanin is a recently isolated neuropeptide that is of particular interest in dementing disorders because of its known colocalization with choline acetyltransferase in magnocellular neurons of the basal nucleus of Meynert. These neurons degenerate in Alzheimer's disease, and there is a corresponding deficiency of cortical choline acetyltransferase activity. In the present study, galanin-like immunoreactivity was measured in the postmortem cerebral cortex and hippocampus of 10 controls and 14 patients who had had Alzheimer's disease. Significant reductions of choline acetyltransferase activity (50-60%) were found in all regions examined; however, there was no significant effect on concentrations of galanin-like immunoreactivity. Similar measurements were made in postmortem tissues of 12 control and 13 demented Parkinsonian patients who had had Alzheimer-type cortical pathology. Choline acetyltransferase activity was again significantly decreased in all regions examined but there were no significant reductions in galanin-like immunoreactivity. Experimental lesions of the fornix in rats produced parallel significantly correlated reductions of both choline acetyltransferase activity and galanin-like immunoreactivity in the hippocampus. Galanin-like immunoreactivity in the human hypothalamus consisted of two molecular-weight species on gel-permeation chromatography, and two forms were resolved by reverse-phase HPLC. The paradoxical preservation of galanin-like immunoreactivity, despite depletion of the activity of choline acetyltransferase, with which it is colocalized, is as yet unexplained. Recent studies have shown that galanin inhibits both acetylcholine release in the hippocampus and memory acquisition; therefore, preserved galanin may exacerbate the cholinergic and cognitive deficits that accompany dementia.