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B M Pogell

Publications and source records attributed to B M Pogell.

At least 19 recordsLinked to original sources
PubMed1998

The pamamycins: developmental autoregulators and antibiotics from Streptomyces alboniger. A review and update.

A brief review and update of current studies on the pamamycins is presented. The pamamycins are a group of macrolides isolated from Streptomyces alboniger which function as autoregulators in streptomycetes. At low concentrations, they stimulate the formation of aerial mycelium and, at higher concentrations, they inhibit the growth of these organisms. In addition, the pamamycins have potent antibiotic activity against gram-positive bacteria, fungi and mycobacteria. The possible mode of action of these compounds is discussed, together with their possible value against multiple antibiotic-resistant M. tuberculosis.

Anti-Bacterial Agents↗
PubMed1996

Metabolism of twelve herbicides by Streptomyces.

Experiments were conducted to assess the ability of Streptomyces (strain PS1/5) to metabolize twelve herbicides representing several different classes including: acetanilides, triazines, ureas, uracils, and imidazoles. Incubations in aqueous culture with dextrin as carbon source and either ammonium or Casamino acids as nitrogen source resulted in transformations (> 50%) of eight of the herbicides tested: alachlor, metolachlor, atrazine, prometryne, ametryne, linuron, tebuthiuron, and bromacil; the remaining four herbicides (cyanazine, diuron, metribuzin, and imazapyr) were also transformed, but to a lesser extent. In most instances, biotransformations occurred concurrently with growth and results were consistent regardless of the nitrogen source (ammonium vs. Casamino acids). However, in some instances there were differences in rates of biotransformation as a consequence of the nitrogen source (e.g. alachlor, metribuzin), suggesting the selective induction of certain metabolic enzymes; in other instances biotransformations were not associated with growth, suggesting secondary metabolism. An experiment was also conducted to assess the ability of Streptomyces (strain PS1/5) to metabolize atrazine contaminated soil. Inoculation of soil amended with 20 micrograms/g of atrazine and 5% chitin as carbon source resulted in ca. 78% removal of atrazine within 28 days. These data suggest that Streptomyces species may be potential candidates for soil inoculation to bioremediate herbicide contaminated soils.

Biodegradation, Environmental↗
PubMed1992

The effect of signal sequences on the efficiency of secretion of a heterologous phosphotriesterase by Streptomyces lividans.

A heterologous phosphotriesterase (parathion hydrolase) containing the native Flavobacterium species signal sequence was previously shown to be secreted by Streptomyces lividans. Western blot analysis of the recombinant phosphotriesterase produced by S. lividans demonstrated only the mature form extracellularly but both processed and unprocessed forms in cell-associated samples. To investigate the efficiency of secretion in Streptomyces, a construction was made that substituted a native Streptomyces beta-galactosidase signal sequence for the Flavobacterium signal sequence. This resulted in a higher proportion of hydrolase in the extracellular fluid and a lower proportion of parathion hydrolase remaining cell-associated. These results suggest that use of a native Streptomyces signal sequence may result in more efficient secretion of heterologous proteins.

Amino Acid Sequence↗
PubMed1991

Purification and characterization of a secreted recombinant phosphotriesterase (parathion hydrolase) from Streptomyces lividans.

A heterologous phosphotriesterase (parathion hydrolase), previously cloned from a Flavobacterium species into Streptomyces lividans, was secreted at high levels and purified to homogeneity. N-terminal analysis revealed that it had been processed in the same manner as the native membrane-bound Flavobacterium hydrolase. The enzyme consisted of a single polypeptide with an apparent molecular weight of 35,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Substrate specificity studies showed Kms of 68 microM for parathion, 46 microM for O-ethyl O-p-nitrophenyl phenylphosphonothioate, 599 microM for methyl parathion, and 357 microM for p-nitrophenyl ethyl(phenyl)phosphinate. Temperature and pH optima were 45 degrees C and 9.0, respectively. The purified enzyme was inhibited by 1 mM dithiothreitol and 1 mM CuSO4. After chelation and inactivation by o-phenanthroline, however, activity could be partially restored by 1 mM CuCl or 1 mM CuSO4. The results showed that the purified recombinant parathion hydrolase has the same characteristics as the native Flavobacterium hydrolase. This system provides a source of milligram quantities of parathion hydrolase for future structural and mechanism studies and has the potential to be used in toxic waste treatment strategies.

Amino Acid Sequence↗
PubMed1991

Genetic and biochemical evidence for the lack of significant hydrolysis of soman by a Flavobacterium parathion hydrolase.

Pure recombinant Flavobacterium parathion hydrolase (an organophosphorus acid anhydrase) from Streptomyces lividans was found to hydrolyze the toxic nerve agent soman at only 0.1% of the rate observed with parathion as substrate. Studies with wild-type and recombinant strains of S. lividans support the lack of significant soman breakdown by the hydrolase and also indicate the presence in S. lividans of other significant hydrolytic enzymatic activity towards soman.

Aryldialkylphosphatase↗
PubMed1981

Mode of action of pamamycin in Staphylococcus aureus.

Pamamycin was previously identified as a stimulator of aerial mycelium formation in Streptomyces alboniger and as a new antibiotic. Studies in Staphylococcus aureus grown in brain heart infusion broth showed that this antibiotic was bacteriostatic at 0.1 to 0.3 U/ml and bactericidal at 0.5 U/ml or higher. At concentrations which inhibited growth ca. 40%, pamamycin inhibited the uptake of nucleosides and Pi, as well as purine and pyrimidine bases, and the incorporation of these precursors into nucleic acids. Under the same conditions, the antibiotic had no effect on protein and cell wall synthesis, glucose utilization, or the uptake of amino acids, 2-deoxyglucose, or Mn2+. Further studies suggested that the primary action of pamamycin was on transport processes rather than de novo ribonucleic acid and deoxyribonucleic acid synthesis. Direct in vitro studies of nucleoside transport with isolated membrane vesicles confirmed this conclusion. Pamamycin bound tightly to bacterial membranes and induced significant release of ultraviolet-absorbing material at bactericidal concentrations. It was concluded that the mechanism of growth inhibition involves alteration of membrane-associated cellular functions. Inhibition of Pi transport is a likely primary target for this effect.

Alanine↗
PubMed1979

Simultaneous loss of multiple differentiated functions in aerial mycelium-negative isolates of streptomycetes.

Germination and outgrowth of spores of Streptomyces alboniger, Streptomyces scabies, and Streptomyces violaceus-ruber in the presence of intercalating dyes resulted in a high frequency (2 to 20%) of occurrence of aerial mycelium-negative (Amy-) isolates. Coincident with the appearance of the Amy- trait was the loss of several differentiated functions, including the characteristic pigments and earthy odor of the wild types. All S. alboniger, 27% of S. scabies, and 39% of the S. violaceus-ruber Amy- isolates were arginine auxotrophs. The missing enzyme step was identified as argininosuccinate synthetase by using a sensitive microassay for estimation of enzyme activity. The remainder of the S. scabies and S. violaceus-ruber isolates were prototrophs. In addition, S. alboniger Amy- isolates failed to produce or respond to the stimulator of aerial mycelium formation isolated from the wild type. The Amy- isolates did not revert to either Amy+ of Arg+. The lack of any detectable reversion, coupled with the high frequency of curing, supports the idea that a deletion of genetic material, possibly a plasmid, has occurred.

Acridine Orange↗
PubMed1979

Pamamycin: a new antibiotic and stimulator of aerial mycelia formation.

Pamamycin is a new antibiotic isolated from Streptomyces alboniger ATCC 12461. The antibiotic is active in vitro against Gram-positive bacteria, Neurospora, and Mycobacteria. The compound also acts as a streptomycete differentiation effector. It stimulates aerial mycelia formation in the producing organism. The new antibiotic of elemental composition C36H63NO7 is completely different from puromycin, also produced by this strain. The present communication deals with the isolation, properties, and preliminary characterization of pamamycin.

Antifungal Agents↗
PubMed1977

Specific factors influencing histotypic aggregation of chick embryo hepatocytes.

Conditions are described for the reproducible assay of substances affecting the in vitro rate of aggregation of isolated chick embryo hepatocytes. Two low molecular weight (less than 1000) fractions--one that promotes hepatocyte aggregation (HAP) and the other that inhibits this stimulation (HAI)--have been isolated and partially purified from adult chicken liver. One major active component of HAP was identified as taurine (2-aminoethanesulfonate). The presence of HAP during the entire time of assay was required for largest aggregate formation. HAP had no effect on aggregation of chick embryo neural retina, kidney, or heart cells. Our results and the fact that puromycin completely inhibits aggregate formation suggest that HAP and HAI influence the specific synthesis and interaction of membrane macromolecules involved in the aggregation process.

Animals↗
PubMed1976

Control of differentiation in streptomycetes: involvement of extrachromosomal deoxyribonucleic acid and glucose repression in aerial mycelia development.

When Streptomyces alboniger spores were grown in Hickey-Tresner broth containing 5 muM ethidium bromide, a high frequency of permanently cured aerial mycelia-negative (am-) colonies was recovered. The appearance an am- colonies was time dependent: a very low frequency (0.3%) at zero time, a maximum (9 to 21%) after 2 to 5 days of growth, and a decline again to low frequencies later in the growth cycle. On agar, cured am- colonies of S. alboniger still produced puromycin. The development of aerial mycelia in S. alboniger, S. scabies, and S. coelicolor was also sensitive to glucose repression. Colonies grown on Hickey-Tresner agar containing 2% glucose remained phenotypically am- throughout the observation period. Adenine (2.5 mM or greater), and to a lesser extent adenosine and guanosine, specifically reversed the repression. The accumulation of undissociated organic acids appears to be involved in glucose repression of aerial mycelia formation. However, this does not appear to be the case with puromycin production in S. alboniger; glucose repression was observed over the pH range 5.0 to 7.5.

Adenine↗
PubMed1975

Involvement of cytosol proteins in oleate activation of rabbit liver fructose-1,6-diphosphatase.

Dialyzed rabbit liver cytosol was specifically freed of endogenous fructose-1,6-diphosphatase by immunoadsorption on a column of Sepharose-immobilized anti-fructose-1,6-diphosphatase. This material increased the specific activity of homogeneous enzyme to the maximal rate observed with EDTA and shifted the pH optimum from 8.4 to 7.4. With oleate or other fatty acids as activators, the hydrolysis of fructose-1,6-diphosphatase by enzyme, at neutral pH, showed nonlinear initial rates dropping to lower linear rates. Cytosol activator acted synergistically with oleate both to increase neutral enzyme activity and to maintain the high initial catalytic rates. After sucrose density centrifugation or gel filtration, the cytosol had no effect by itself, but still potentiated oleate activation. The factor was destroyed by treatment with subtilisin or trypsin, but all attempts to identify a unique protein component in cytosol were unsuccessful. The presence of Na dodecyl-SOJ, deoxycholate, or urea did not improve the resolution of the factor, but these compounds did lower the K50 for activation by cytosol. Since fatty acids are the only unique compounds which have been isolated from cytosol which activated fructose-1,6-diphosphatase, it appears that soluble proteins can act as natural carriers for the fatty acids. This was supported by the fact that both dialyzed rabbit alpha-globulins and muscle phosphofructokinase also acted synergistically with oleate in a manner similar to cytosol. Phosphatidic acid and phosphatidylserine activated fructose-1,6-diphosphatase, and their action was synergistic with oleate. Glutathione (1 mM) activated the enzyme 5-fold at pH 7.3 and its effects were additive with oleate and cytosol or alpha-globulins.

Albumins↗
PubMed1975

Biosynthesis of puromycin in Streptomyces alboniger: regulation and properties of O-demethylpuromycin O-methyltransferase.

Mechanisms for regulation of puromycin biosynthesis in Streptomyces alboniger were studied by measuring the levels of S-adenosyl-l-methionine:O-demethylpuromycin O-methyltransferase. The enzyme was released in soluble form from mycelia by 3 to 5 min of sonication at 4 C. Maximal specific activities of 0.7 and 0.1 nmol/min per mg of protein were found in cells grown in corn steep liquor-corn starch and Hickey-Tresner media, respectively. In both media, the O-methyltransferase activity rose from low levels to a maximum during midlogarithmic growth and then declined or disappeared completely (in Hickey-Tresner medium) during stationary phase. Either glucose (1%) or ethidium bromide (5 muM) reduced O-methyltransferase formation to very low levels with no effect on overall growth. Complete glucose repression of antibiotic formation occurred on agar. Cells grown in the presence of ethidium bromide continued to produce low enzyme levels after regrowth in the absence of dye, but formed normal amounts of puromycin on Hickey-Tresner agar. The O-methyltransferase, either crude or purified, was rapidly inactivated at 37 C. Each substrate alone, or both together at lower concentrations, protected against this loss of activity. Puromycin inhibited the transferase. Regulation of O-methyltransferase synthesis in S. alboniger includes (i) induction early in growth that is susceptible to catabolite repression and differential inhibition by ethidium bromide, and (ii) protection of the enzyme from inactivation by increased intracellular levels of its substrates. The O-methyltransferase was purified 30- to 40-fold by a combination of protamine sulfate precipitation, ammonium sulfate fractionation, adsorption and gradient salt elution from diethylaminoethyl-cellulose and Sephadex G-200 gel filtration. The enzyme was very unstable, even at low temperatures, upon purification beyond the salt fractionation step, but was stabilized by the addition of S-adenosyl-l-methionine during later stages of purification.

Culture Media↗