Actinomadura sp. strain 2966 can effectively convert compactin to pravastatin. The degree of conversion observed was 65% to 78% of compactin added and 65% to 88% of compactin taken up, depending on the concentration of compactin and duration of the experiment. Increasing the compactin concentration resulted in a higher final pravastatin concentration especially when compactin was added intermittently. Higher glucose concentrations had no effect on the bioconversion although uptake of compactin was inhibited. The conversion was linear over 16 hours. The system requires no induction and thus appears to be different from previously studied hydroxylases from actinomycetes.

In vivo 31P nuclear magnetic resonance analysis of Escherichia coli cells showed that the intracellular concentration of P(i) remained constant in wild-type and in a glpT mutant strain whether the cells were grown on excess (2 mM) P(i) or sn-glycerol-3-phosphate as a phosphate source. The function of the phoA promoter (measured by beta-galactosidase activity in a phoA-lacZ fusion strain) was repressed when glpT+ cells were utilizing sn-glycerol-3-phosphate as the sole source of phosphate. These cells were devoid of alkaline phosphatase activity. However, the phoA promoter was fully active in a glpT mutant. These results indicated that the repression of the enzyme synthesis was not due to a variation in the level of cytoplasmic P(i) but was due to the P(i) excreted into the periplasm and/or to the medium.

A transport system for thymine was investigated in a Lactobacillus casei mutant lacking thymidine phosphorylase activity (the first enzyme required for thymine utilization). Transport was dependent on an energy supply; transport was inhibited by the uncouplers carbonylcyanide-m-chlorophenylhydrazone (CCCP) and 2,4 dinitrophenol (DNP), and also by sodium azide and N,N′-dicyclohexylcarbodiimide (DCCD). Thymine transport was inhibited by some uracil and adenosine derivatives and by thymidine, but was not affected by guanosine, deoxycytidine or azacytidine. Inhibition by p-chloromercurybenzoate (PCMB) was reversed by dithiothreitol (DTT).

The transport of inorganic phosphate has been studied inAcinetobacter lwoffi JW11. During growth on excess phosphate, only one transport system was present, with an apparent Km of 1.4 μM. When cells were starved for phosphate, a second uptake system with an apparent Km of 110 nM was also synthesized. The two transport systems could be distinguished by differing sensitivities to the phosphate analogs arsenate and 2-aminoethylphosphonate. Both systems were inhibited by carbonylcyanidem-chlorophenylhydrazone, and to a lesser extent by Na azide. The high-affinity transport system was inactivated by osmotic shock treatment and by spheroplast formation. Preliminary evidence for a phosphate-binding protein in the osmotic shock fluid is presented. The isolation of a mutant constitutive for the high-affinity transport system is described.

Lactobacillus casei cells grown on excess thymine or on folic acid contained low levels of thymidine phosphorylase. On the other hand, thymine starved cells and also cells of a thymidine-monophosphate-kinase-defective mutant grown on excess thymine, possessed derepressed levels. These results suggest that the synthesis of thymidine phosphorylase is regulated by the end product of the thymidine-triphosphate-biosynthetic pathway. L. casei cells lacked 2-deoxyribose-1-phosphate-mutase activity and did not grow on 2-deoxyribose or thymidine as the sole-carbon source. Growth in the presence of thymidine did not result in induction of thymidine-phosphorylase synthesis, probably due to the inability of the cell to convert it to 2-deoxyribose-5-phosphate, which is known to act as an inducer in E. coli cells. Thymidine triphosphate inhibited non-competitively the activity of thymidine phosphorylase. It was also inhibited by dihydrofolic acid.

Essential oil from Achillea fragrantissima exerted a bactericidic effect on several gram positive and gram negative bacterial strains, as well as on Candida albicans. The oil was fractionated on sillica gel columns by a gradient of ether in petrol ether (30-degrees-C-40-degrees-C). Two fractions which contained less polar compounds were active against C albicans only. The fractions which contained more polar compounds inhibited the growth of all the microorganisms tested. One of these compounds was identified as terpinen-4-ol. Commercial terpinen-4-ol had a similar antimicrobial activity.

Several phosphomonoesterases and diesterases with various pH optima have been observed inAcinetobacter lwofi JW11. The osmotic shock fluids contained only those with an alkaline pH optimum. The synthesis of these phosphatases was regulated by external Pi concentrations. The shock fluids were fractionated by chromatography, yielding three fractions, two of which had hydrophobic properties. One of these contained an alkaline phosphatase that specifically required Ca2+ for activity. The diesterases required various divalent cations for their function. Mutants that lack phosphomonoesterase or both phosphomonoesterase and phosphodiesterase activities were isolated.

Escherichia coli cells treated with the essential oil from the plantAchillea fragrantissima released five polypeptides as well as K+ ions into the incubation medium. The oil also inhibited the respiration ofE. coli cells and reduced their ATP content. Electron micrographs showed that oil-treated cells were permeable to uranyl acetate. The effect of the essential oil on the cell membrane is discussed.

cells treated with the essential oil from the plant released five polypeptides as well as K ions into the incubation medium. The oil also inhibited the respiration of cells and reduced their ATP content. Electron micrographs showed that oil-treated cells were permeable to uranyl acetate. The effect of the essential oil on the cell membrane is discussed.

Crude extracts of Lactobacillus casei, were found to possess both thymidine phosphorylase and uridine phosphorylase activities, which were associated with a single sucrose gradient band. However, using dye ligand chromatography (Green A), two enzymatic fractions were obtained each of which possessed mainly one of these activities. By this procedure, the uridine phosphorylase was purified 329-fold and the thymidine phosphorylase about 25-fold. The existence of the two phosphorylases was supported by Km, Ki, pH optimum, and heat stability studies. Identical bands were obtained on sucrose gradient sedimentation for the purified enzymes and for their mixture in a crude extract, suggesting that they have similar sedimentation coefficients, and do not form an aggregate in the crude extract.

The essential oils from four Artemisia herba alba populations collected in Israel were investigated for their antibacterial and antispasmodic activities. All the oils had slight antibacterial activities in the concentration range of 1-2 mg/ml. Some correlations between the chemical composition of the oils and their antibacterial activity was observed. All the essential oils tested showed marked antispasmodic effects on rabbit jejunum at about 1 × 10−5%. The antibacterial together with the antispasmodic effects may explain the extensive use of A. herba alba in folk medicine.

The intracellular nucleotide pool of Escherichia coli W3110 reproducibly changes from conditions of growth in phosphate excess to phosphate starvation, with at least two nucleotides appearing under starvation conditions and two nucleotides appearing only under excess phosphate conditions. Strains bearing a deletion of the phoA gene show the same pattern, indicating that dephosphorylation by alkaline phosphatase is not responsible for the changes. Strains with mutations in the phoU gene, which result in constitutive expression of the pho regulon, show the nucleotide pattern of phosphate-starved cells even during phosphate excess growth. These changes in nucleotides are therefore due to phoU mutation but not to alkaline phosphatase constitutivity. In fact, a phoR (phoR68) mutant strain has the patterns of the wild type in spite of being constitutive for alkaline phosphatase. That these nucleotides might be specific signals for pho regulon expression was supported by the fact that the two nucleotides appearing under phosphate starvation induced the synthesis of alkaline phosphatase in repressed permeabilized wild-type cells under conditions of phosphate excess.

The antibacterial activity of Artemisia herba-alba was investigated. Only its essential oil was active against some Gram-positive and Gram-negative bacteria. The essential oil was fractionated by column chromatography, and these fractions were tested for antibacterial activity. The principal component of the most active fraction was santolina alcohol.

The regulation of lactate dehydrogenase in Bacillus subtilis was determined under a variety of growth conditions and in mutants blocked in the citric acid cyle. The synthesis of lactate dehydrogenase increased sharply concomitantly upon the exhaustion of glucose from the medium and the onset of the stationay phase. The synthesis of lactate dehydrogenase may be under catabolite repression control. Studies with mutants bloced in the citric acid cylce showed that lactate dehydrogenase is regulated independently of either the oxidative or reductase branches of the cycle. Certain citric acid cycle mutants, e.g., aconitase or succinate dehydrogenase, exhibited very low levels of lactate dehydrogenase while others, e.g., malate dehydrogenase or isocitrate dehydrogenase, showed normal levels. A stage 0 sporulation mutant expressed levels of lactate dehydrogenase more than one-thousand-fold higher than the low group of citric acid cycle mutants. The induction of lactate dehydroganase was shown to be independent of the accumulation of its substrate, pyruvate.

The development of the luminescence system in Beneckea harveyi is controlled by cyclic nucleotides at the level of transcription. In the wild type, it is repressed by exogenously added guanosine 3':5'-cyclic monophosphate and this repression is overcome by the addition of adenosine 3':5'-cyclic monophosphate. These observations alone support a model in which these nucleotides act antagonistically. On the other hand, in a mutant requiring adenosine 3':5'-cyclic monophosphate for maximum luminescence, guanosine 3':5'-cyclic monophosphate stimulates the synthesis of the luminescence system at low concentrations and inhibits it at higher concentrations. These results are apparently not consistent with a model involving a simple antagonistic effect of guanosine 3':5'-cyclic monophosphate on the action of adenosine 3':5'-cyclic monophosphate.

We have isolated a mutant of the luminous bacterium Beneckea harveyi, which requires exogenous adenosine 3',5'-monophosphate (cyclic AMP) to synthesize luciferase and emit light. The mutant was pleiotropic, lacking not only the ability to luminesce, but also the capacities to form flagella and the ability to utilize a variety of carbohydrates for growth. All these deficiencies could be corrected by added cyclic AMP. The cyclic AMP-induced de novo synthesis of luciferase was possible only after autoinduction had occurred. The induction time by cyclic AMP ranged between 6 and 10 min at 27 degrees C.

Cyclic AMP levels in glucose and succinate-fluid and ammonia-limited glucose-containing continuous cultures of Escherichia coli were measured at different bacterial growth rates. Intracellular cyclic AMP concentrations were fairly constant (about 5 μM) at all dilution rates used when glucose was limiting. In ammonia-limited glucose cultures the cyclic AMP content was much lower (about 0.3 μM). In succinate-limited cultures cyclic AMP levels fell from 2.7 to 0.8 μM as dilution rate increased from 0.05 to 0.4 h−1.The effects of cyclic AMP on respiratory and carbon catabolic enzyme levels were studied. There was no indication of a direct cyclic AMP involvement in the regulation of these cellular functions. It seems more likely that the variations in enzyme levles observed resulted from variation of the specific growth rate of cultures.