| inhibition of bacterial wall lysins by lipoteichoic acids and related compounds. | | 1975 | 1027 |
| altered nutritional requirements associated with mutations affecting the structures of ribonucleic acid polymerase in lactobacillus casei. | rifampin-resistant mutants were isolated from lactobacillus casei s1 and examined for possible simultaneous alteration in nutritional properties. among the 36 mutants obtained either spontaneously or after mutagenesis with 2-aminopurine, 22 were found to be altered with respect to the specific growth requirements. the majority (20 of 22) of the latter mutants were shown to require l-glutamine in addition to the nutrients required by the parental strain for maximal growth, whereas the remaining m ... | 1976 | 1379 |
| radioassay for serum and red cell folate. | a simple, reliable assay for serum and red cell folate is described. it uses plain untreated liquid or powdered milk, requiring no special handling or purification, as binder. such milk makes it possible to ignore endogenous serum folate binder, since crude (but not purified) milk contains a factor which releases folate from serum binder. it simplifies counting radioactivity by employing a gamma emitting isotope of pteroylglutamic acid (pga), namely the 125i-tyramide of pga. like the 3h-pga assa ... | 1976 | 1452 |
| large-scale purification and characterization of dihydrofolate reductase from a methotrexate-resistant strain of lactobacillus casei. | dihydrofolate reductase has been purified from a methotrexate-resistant strain of lactobacillus casei ncb 6375. by careful attention to growth conditions, up to 2.5 g of enzyme is obtained from a 400 litre culture. the purification procedure, involving poly-ethyleneimine treatment, deae-cellulose chromatography and affinity chromatography on methotrexate-aminohexyl-sepharose, operates on the gram scale, with overall yields of 50-60%. elution of the affinity column by reverse (upward) flow was us ... | 1976 | 10886 |
| the role of microflora in development of graft-versus-host disease. | | 1976 | 11583 |
| total folate binding capacity of normal human plasma, and variations in uremia, cirrhosis, and pregnancy. | the current study presents evidence that all human serum contains a class of high-affinity folate binders (ka=2.8 x10(10 liters/mole), which migrate as a single peak on gel filtration. failure of previous studies to detect this characteristic in all but a minority of subjects is attributable to its variable, often total, saturation. direct measurement of the total folate binding capacity (tfbc) has been made possible by dissociation of endogenous folate-binder complexes at acid ph, removal of fr ... | 1976 | 11860 |
| transport and metabolism of vitamin b6 in lactic acid bacteria. | streptococcus faecalis 8043 concentrates extracellular 3hpyridoxal or 3hpyridoxamine primarily as the corresponding 5'-phosphates. accumulation of pyridoxamine requires an exogenous energy source and is inhibited by glycolysis inhibitors. a membrane potential is not required for transport of pyridoxamine, and an artificially generated potential does not drive uptake in this organism. based on this and other evidence, it is concluded that s. faecalis accumulates pyridoxamine by facilitated diffus ... | 1977 | 14135 |
| comparative studies of lactic acid dehydrogenases in lactic acid bacteria. i. purification and kinetics of the allosteric l-lactic acid dehydrogenase from lactobacillus casei ssp. casei and lactobacillus curvatus. | the stability, ph-dependence and kinetic properties of the mn2+ and fdp-activated nad-dependent lactic acid dehydrogenases from lactobacillus casei ssp. casei (atcc 393) and l. curvatus (dsm 20010) were studied after the enzymes were purified to homogeneity by affinity chromatography. both enzymes are virtually unidirectional, catalysing efficiency only the reduction of pyruvate. they are similar with respect to the effector requirement and ph-optimum. they differ, however, in their electrophore ... | 1977 | 14601 |
| study on l-malic acid catabolism by "lactobacillus casei" cells immobilized into polyacrylamide gel lattice (author's transl). | study on l-malic acid catabolism by lactobacillus casei cells immobilized into polyacrylamide gel lattice has shown that the ph profil of malic acid decarboxylase activity does not differ significantly from that of free cells. the apparent enzymatic constant value as determined by the warburg manometric method is 5 x 10(-3) m for free cells and 1.25 x 10(-2) m for immobilized cells. malic acid decarboxylase activity can be preserved in immobilized cells over a 12 month period when the reaction v ... | 1976 | 15492 |
| 1h nuclear magnetic resonance studies of lactobacillus casei dihydrofolate reductase: effects of substrate and inhibitor binding on the histidine residues. | | 1977 | 16268 |
| 1h nuclear magnetic resonance studies of the tyrosine residues of selectively deuterated lactobacillus casei dihydrofolate reductase. | | 1977 | 16269 |
| purification and properties of a membrane-associated, folate-binding protein from lactobacillus casei. | a folate-binding protein has been solubilized from lactobacillus casei by treatment of membrane preparations with triton x-100 in the presence of 3hfolate. the protein-folate complex was purified 100-fold and recovered in a 22% yield by adsorption and elution from microgranular silica (quso g-32), followed by passage through sephadex g-150. when subjected to sodium dodecyl sulfate/polyacrylamide gel electrophoresis, the purified preparations showed only a single, protein-staining band whose mole ... | 1977 | 16917 |
| reduction of oxidised folates by dihydrofolate reductase from methotrexate-resistant lactobacillus casei. | the use of alternative substrates by dihydrofolate reductase (5,6,7,8-tetrahydrofolate: nadp+ oxidoreductase, ec 1.5.1.3) was investigated as a possible mechanism for the resistance of lactobacillus casei to the cytotoxic drug methotrexate. the reduction of folic acid and 10-formylfolic acid by homogeneous enzyme was compared to that of the normal substrate, dihydrofolic acid. the three substrates have different ph optima and km values. in addition, it was found that the reduction of 10-formylfo ... | 1977 | 18181 |
| 19 fnuclear magnetic resonance studies of ligand binding to 3-fluorotyrosine-and 6-fluorotryptophan-containing dihydrofolate reductase from lactobacillus casei. | | 1977 | 19051 |
| 31p nmr studies of the binding of adenosine-2'-phosphate to lactobacillus casei dihydrofolate reductase. | | 1977 | 19299 |
| dihydrofolate reductase from amethopterin-resistant lactobacillus casei. effects of ph, salts, temperature, and source of nadph on enzyme activity and substrate specificity studies. | | 1977 | 20050 |
| the charge state of substrates and inhibitors when bound to lactobacillus casei dihydrofolate reductase proceedings. | | 1977 | 20381 |
| acid production from lycasin, maltitol, sorbitol and xylitol by oral streptococci and lactobacilli. | the acid production from maltitol was compared with the acid production from hydrogenated starch hydrolysate (lycasin), sorbitol and xylitol by a number of oral strains and reference strains of streptococcus mutans, s. sanguis, s. salivarius, s. mitior, s. milleri, s. faecalis, s. faecium, s. avium, lactobacillus casei and l. salivarius. the polyols were added to a final concentration of 1.0% to two different basal media. incubation was performed at 37 degrees c for 7 days after which the ph was ... | 1977 | 21508 |
| kinetics of sulfhydryl group modification of thymidylate synthetase: a proposal for activation of catalytic cysteinly residues. | | 1978 | 23783 |
| microbiological measurement of folic coenzymes. ii. effect of the ph of ascorbic acid. | | 1977 | 23813 |
| ultraviolet difference-spectroscopic studies of substrate and inhibitor binding to lactobacillus casei dihydrofolate reductase. | the u.v. difference spectra generated when methotrexate, trimethoprim or folate bind to lactobacillus casei dihydrofolate reductase were analysed. the difference spectrum producted by methotrexate binding is shown to consist of three components: (a) one closely resembling that observed on protonation of methotrexate, reflecting an increased degree of protonation on binding; (b) a ph-independent contribution corresponding to a 40 nm shift to longer wavelengths of a single absorption band of metho ... | 1978 | 26334 |
| dihydrofolate reductase from lactobacillus casei. x-ray structure of the enzyme methotrexate.nadph complex. | | 1978 | 29045 |
| extractability of cell wall polysaccharide from lactobacilli and streptococci by autoclaving and by dilue acid. | autoclaving cell wall of streptococcus mutans ingbritt for 15 min under the rantz and randall conditions released one-tenth of the total cell wall carbohydrate, whereas two-thirds was extracted after autoclaving for 180 min. the extract contained the serotype c-specific antigen but lacked the lipoteichoic acid component extracted when whole cells were autoclaved. autoclaving cell wall preparations from other strains of s. mutans and also streptococcus salivarius and streptococcus mitis in 0.85% ... | 1978 | 32140 |
| interrelationships between lactobacilli and streptococci in plaque formation on a tooth in an artificial mouth. | | 1978 | 32164 |
| thymidylate synthetase purified to homogeneity from human leukemic cells. | thymidylate synthetase (5,10-methylenetetrahydrofolate:dump c-methyltransferase, ec 2.1.1.45) from a human leukemic cell line has been purified to homogeneity with one-step affinity column chromatography. the purified enzyme has a specific activity of 3.8 micron/min per mg of protein, which corresponds to a turnover number of 250. these are the highest values reported for a thymidylate synthetase from neoplastic tissue. a ratio of 1.7 mol of 5-fluoro-2'-deoxyuridylate binds per mol of enzyme in ... | 1979 | 34155 |
| interpretation of nuclear magnetic resonance spectra for lactobacillus casei dihydrofolate reductase based on the x-ray structure of the enzyme-methotrexate-nadph complex. | the three-dimensional molecular structure of lactobacillus casei dihydrofolate reductase complexed with nadph and methotrexate has been used to interpret published magnetic resonance spectra for this enzyme. proton resonances from histidine residues and 19f resonances from fluorine-labeled fluorotyrosine and fluorotryptophan dihydrofolate reductase have been assigned in several cases to specific amino acids in the primary sequence. furthermore, the 31p signals from the pyrophosphate moiety of bo ... | 1979 | 34432 |
| circular-dichroism studies of ligand binding to dihydrofolate reductase from lactobacillus casei mtx/r. | circular-dichroism spectra (200--450 nm) were recorded for lactobacillus casei mtx/r dihydrofolate reductase and its complexes with substrates, inhibitors and coenzymes. these spectra are compared with those reported by others for dihydrofolate reductase from other sources. the binding of nadp+ or nadph is associated with the perturbation of one or more aromatic amino acid residues, and there is marked enhancement of the negative c.d. band at 340 nm arising from the dihydronicotinamide chromopho ... | 1979 | 35152 |
| dihydrofolate reductase from lactobacillus casei. stereochemistry of nadph binding. | the nadph molecule binds to dihydrofolate reductase in an extended conformation. several of the individual dihedral angles, especially in the adenine mononucleotide portion of the coenzyme, differ from their minimum energy conformations. the ribose phosphate portions of the coenzyme are involved in numerous specific hydrogen-bonded and charge-charge interactions. the adenine ring resides in an apparently nonspecific hydrophobic cleft and the nicotinamide ring is bound within an intricately const ... | 1979 | 35535 |
| glycerol teichoic acid as an antigenic determinant in a gram-negative bacterium butyrivibrio fibrisolvens. | an antigenic determinant isolated from a strain of the gram-negative bacterium butyrivibrio fibrisolvens reacted with specific antisera to the polyglycerophosphate backbone of membrane teichoic acids of lactobacilli. it gave a reaction of identity with membrane glycerol lipoteichoic acid and glycerol teichoic acid preparations from lactobacilli, and with phenol extracts of other gram-positive bacteria. the antigen-antibody reactions was strongly inhibited by glycerol-phosphoryl-glycerol-phosphor ... | 1975 | 50403 |
| antigenic analyses of lactobacillus fermenti. | antigenic analyses of lactobacillus fermenti were carried out by double immunodiffusion in agar using extracts prepared with cold trichloroacetic acid (tca) or hot dilute hydrochloric acid (hcl). a common antigen of l. fermenti, designated as antigen f by the author, was extracted from whole cells with dilute hcl, but not with tca. the antigen f was also observed in lactobacillus casei. in addition, all strains isolated from human saliva contained antigen 6 in their cell walls, while the antigen ... | 1975 | 50468 |
| cotrimoxazole and folate metabolism. | cotrimoxazole 4 tablets daily (1 tablet = trimethoprim 80 mg and sulphamethoxzole 400 mg) was given for a period of six to fourteen days to 13 inpatients, and serum-folate levels were measured before and one day after the course of treatment. the results were compared with those from 8 patients not receiving antibacterial therapy, tested on admission and one week later. two assay techniques were used, one employing lactobacillus casei and the other 125i-labelled folate isotope dilution. the micr ... | 1976 | 60570 |
| fluorescent pigments in the newly isolated methylotrophs: pseudomonas j16 and methylomonas pl1. | the pigments showing fluorescence maxima at 390, 366, 450-460 and 520 nm at excitation wavelength 254, 366 and 450 nm respectively, were detected in the cells and culture media of the obligate methylotroph methylomonas pl1 and facultative methylotroph pseudomonas j26. the maximum at 520 nm is associated with the occurrence of a flavin pigment enabling growth of lactobacillus casei e atcc-7469 on the vitamin b2 deficient medium. the remaining fluorescence maxima are related to the prosthetic grou ... | 1978 | 81599 |
| essential arginyl residues in thymidylate synthetase. | | 1978 | 96829 |
| folate status during long-term therapy with trimethoprim and sulphadiazine. | it was studied whether treatment with sulphadiazine and trimethoprim for 8 weeks affected the folate status. the therapy did not inhibit the absorption as assessed by the 3h--folic acid absorption (trifa) test. plasma folic acid clearance showed that folate deficiency had not developed. bone marrow studies revealed that the antifolic action of the drugs did not manifest itself at the cellular level. the lactobacillus casei method should not be employed in the determinations of the serum folate c ... | 1978 | 97059 |
| folate analogues altered in the c9-n10 bridge region: n10-toxylisohomofolic acid and n10-toxylisohomoaminopterin. | | 1978 | 97383 |
| dihydrofolate reductase from amethopterin-resistant lactobacillus casei. sequences of the cyanogen bromide peptides and complete sequences of the enzyme. | the complete amino acid sequence of dihydrofolate reductase from an amethopterin-resistant strain of lactobacillus casei has been determined by sequence analysis of peptides produced by cleavage with cyanogen bromide, trypsin, staphylococcal protease, and myxobacter protease. comparison of this sequence with those of reductases from other bacterial sources shows that the enzymes are homologous. the lactobacillus casei reductase sequences shows a 29% sequence identity with that of the escherichia ... | 1978 | 98527 |
| measurement of folates in human plasma and erythrocytes by a radiometric microbiologic method. | a radiometric microbiologic assay for the determination of folic acid in human plasma and red blood cells is described. the assay is based upon the measurement of 14co2 produced from the metabolism of [1-14c] gluconate by lactobacillus casei. the 14co2 evolved was shown to be proportional to the amount of added dl-n-5-methyltetrahydrofolage (dl-n-5-methyl fh4). a total of 26 normal plasma and 57 blood hemolysates were assayed in parallel by this radiometric and the standard (turbidimetric) micro ... | 1978 | 98617 |
| tmp synthetase from lactobacillus casei. | | 1978 | 99641 |
| 5-fluoro-2'-deoxyuridylate-agarose in the affinity-chromatographic purification of thymidylate synthetase. | | 1978 | 99642 |
| 19f nmr of the 5-fluorodeoxyuridylate-thymidylate synthetase binary complex. | | 1978 | 100115 |
| [clinical value of folic acid determination by radioassay]. | | 1978 | 100876 |
| measurement of serum folate by 75se-selenofolate radioassay. results of a multi-institutional clinical trial. | the authors report the multi-institutional evaluation of a radioassay for serum folate utilizing a gamma-labeled folate analog (75se-pteroyl-l-methylselenocysteine). the assay is run as a one-step simultaneous addition at ambient temperature and is completed within 45 minutes. the assay data were reproducible within four study centers and correlated with both the lactobacillus casei diagnostic groups and the clinical pictures. | 1978 | 101078 |
| effect of 5, 10-methylenetetrahydrofolate on the dissociation of 5-fluoro-2'-deoxyuridylate from thymidylate synthetase: evidence for an ordered mechanism. | | 1978 | 101234 |
| peptide hydrolases of lactobacillus casei: isolation and general properties of various peptidase activities. | discovery of an endopeptidase by gel chromatography and separation of 3 exopeptidases (a dipeptidase, an aminopeptidase and a specific carboxypeptidase) from lactobacillus casei ncdo 151 by affinity chromatography is described. the 3 exopeptidases were strongly inhibited by the metal chelators edta and 1,10-phenanthroline but were reactivated with co2+ and mn2+. the ph optima for aminopeptidase, dipeptidase and carboxypeptidase activities were 6.5, 7.6 and 7.2, respectively. maximum activity was ... | 1978 | 101561 |
| detection and localization of peptide hydrolases in lactobacillus casei. | | 1978 | 101562 |
| [volatile fatty acids in gastrointestinal diseases in young infants]. | | 1978 | 101958 |
| 5-nitro-2'-deoxyuridylate: a mechanism-based inhibitor of thymidylate synthetase. | | 1978 | 102324 |
| results with commercial radioassay kits compared with microbiological assay of folate in serum and whole-blood. | we compared results with three commercial folate radioassay kits [bio-rad, new england nuclear (nen), and ria products] with those by microbiological assay for more than 200 samples of human serum and whole blood. all but one kit (nen) compared favorably with the microbiological assay for serum samples, although there were notable diagnostic discrepancies. two kits (nen and bio-rad) were tested on whole-blood samples; both yielded values significantly higher than those by microbiological assay. ... | 1978 | 102464 |
| comparison of radioassay and microbiological assay for serum folate, with clinical assessment of discrepant results. | folate assays by use of radiolabeled folate provide obvious practical advantages over the standard microbiological assay, but remain incompletely tested. we therefore compared results for 415 sera with a kit involving 3h-labeled folate and the lactobacillus casei microbiological method. we examined the patients' data when there were discrepancies between the two methods. although the correlation overall was satisfactory, results were discrepant in 25% of cases. in 74% of the latter, the radioass ... | 1978 | 102465 |
| 5-nitro-2'-deoxyuridine 5'-monophosphate is a potent irreversible inhibitor of lactobacillus caesi thymidylate synthetase. | | 1978 | 103545 |
| adenosine triphosphate content in lactobacillus casei and the blender-resistant phage-cell complex-forming ability of cells on infection with pl-1 phage. | the intracellular atp content of lactobacillus casei atcc 27092 grown in a glucose-containing medium was almost constant (2 to 3 microgram/mg dry wt. cells) through the early to middle stage of logarithmic phase, but it was lowered to less than 0.1 microgram/mg after cessation of growth owing to the exhaustion of available glucose. all the cells in the early stage of stationary phase were still viable and thus considered to be in a starved state. when such starved cells were infected with pl-1 p ... | 1979 | 104000 |
| transfer of plasmid-mediated antibiotic resistance from streptococci to lactobacilli. | the transmissible plasmid pambeta1, which codes for erythromycin and lincomycin resistance, was conjugally transferred from a lancefield group f streptococcus to a strain of streptococcus avium. both organisms served as pambeta1 donors for three strains of lactobacillus casei. introduction of pambeta1 into one of the l. casei strains caused the organism to lose its native 6.7 x 10(6)-dalton plasmid. loss of the native plasmid produced no alterations in the organism's growth characteristics or fe ... | 1979 | 104973 |
| the primary structure of lactobacillus casei thymidylate synthetase. i. the isolation of cyanogen bromide peptides 1 through 5 and the complete amino acid sequence of cnbr 1, 2, 3, and 5. | thymidylate synthetase from lactobacillus casei was s-carboxymethylated and degraded by treatment with cyanogen bromide. although the protein contains 6 methionine residues, only 5 cyanogen bromide peptides were obtained due to the presence of 1 methionine on the nh2 terminus and another adjacent to a threonine residue which was resistant to cleavage. the peptides were isolated by differential extraction, first with ammonium acetate, then pyridine acetate, and finally the residue was solubilized ... | 1979 | 105003 |
| the primary structure of lactobacillus casei thymidylate synthetase. ii. the complete amino acid sequence of the active site peptide, cnbr 4. | the 102 amino acid residues of cnbr 4, the largest of 5 cyanogen bromide peptides from the lactobacillus casei thymidylate synthetase were completely sequenced by means of limited tryptic, tryptic, chymotryptic, and staphylococcal protease peptides. cnbr 4 contains both of the cysteines in an enzyme subunit, with the 5-fluorodeoxyuridylate-reactive cysteine at residue 198 and the other at residue 244. | 1979 | 105004 |
| the primary structure of lactobacillus casei thymidylate synthetase. iii. the use of 2-(2-nitrophenylsulfenyl)-3-methyl-3-bromoindolenine and limited tryptic peptides to establish the complete amino acid sequence of the enzyme. | | 1979 | 105005 |
| n-benzoyl derivatives of amino acids and amino acid analogs as inhibitors in microbial antitumor screen. | | 1979 | 106107 |
| enzyme affinity of the 5,6-dihydro derivatives of the substrate and product of thymidylate synthetase catalysis. | the 5,6-dihydro derivatives of 2'-deoxyuridine 5'-phosphate (2) and 2'-deoxythymidine 5'-phosphate (3) were synthesized and characterized. the affinities of 2 and 3 were compared to those of the substrate (2'-deoxyuridine 5'-phosphate) and product (2'-deoxythymidine 5'-phosphate) of the reaction catalyzed by thymidylate synthetase. in both cases, the enzyme affinity of the 5,6-dihydro derivatives was 50 times less than that of the substrate or product. the conclusions from this study are that a ... | 1979 | 106122 |
| [results of measuring the modulus of elasticity of microorganism cell walls]. | the elasticity modulus of escherichia coli cell walls was found to change in the course of growth of the culture. it decreased in the middle of the exponential phase, apparently as a result of intensification of biosynthetic and related to them transport processes at this period. if the cells were treated with edta, their elasticity modulus was lower, by an order of magnitude, than that of the control cell walls. if the cells were treated with lysozyme, the elasticity modulus of their walls decr ... | 1979 | 106226 |
| bacterial and strain specificities in opsonization, phagocytosis and killing of streptococcus mutans. | opsonization of streptococcus mutans, followed by phagocytosis and killing by polymorphonuclear leucocytes has been postulated as an effector mechanism in protection against dental caries. opsonization was studied by using sera from monkeys immunized with killed strep. mutans (sero-type c) and compared with sera from sham-immunized monkeys. antibodies to strep. mutans (sero-type c) induced maximal phagocytosis and killing of serotypes c and e, and this was significantly greater than with serotyp ... | 1979 | 106996 |
| interpretation of serum and red cell folate results. a comparison of microbiological and radioisotopic methods. | serum folate and red blood cell folate levels were measured in 167 patients using a microbiological method (lactobacillus casei) and a commercial 125i radioassay kit. the results of the two methods were compared and related to the clinical findings to see which method more truly reflected the physiological folate status of the patient. there was a good linear correlation between the methods for both serum folate and red cell folate over the whole range encountered and the mean results obtained w ... | 1979 | 107505 |
| mechanism of folate transport in lactobacillus casei: evidence for a component shared with the thiamine and biotin transport systems. | lactobacillus casei cells have been shown previously to utilize two separate binding proteins for the transport of folate and thiamine. folate transport, however, was found to be strongly inhibited by thiamine in spite of the fact that the folate-binding protein has no measurable affinity for thiamine. this inhibition, which did not fluctuate with intracellular adenosine triphosphate levels, occurred only in cells containing functional transport systems for both vitamins and was noncompetitive w ... | 1979 | 108244 |
| evidence for a sequential interaction of the subunits of thymidylate synthetase. | | 1979 | 108277 |
| effect of n-trifluoroacetyl derivatives of amino acids and amino acid analogs on microbial antitumor screen. | eighteen trifluoroacetyl derivatives of amino acids and of amino acid analogs were prepared and tested for growth-inhibitory activity using a lactobacillus casei system as a prescreen for antitumor activity. of the compounds tested, the trifluoroacetyl derivatives of o-, m-, and p-fluorophenylalanine and of beta-3-thienylalanine showed modest activity; trifluoroacetyl derivatives of phenylalanine and of beta-2-thienylalanine showed marginal activity. the activity exhibited by the active trifluor ... | 1979 | 108385 |
| biochemical determinants of tumor sensitivity to 5-fluorouracil: ultrasensitive methods for the determination of 5-fluoro-2'-deoxyuridylate, 2'-deoxyuridylate, and thymidylate synthetase. | techniques have been developed to measure fdump, the active metabolite of 5-fura; thymidylate synthetase (tmp synthase; 5,10-methylenetetrahydrofolate:dump c-methyltransferase, ec 2.1.1.45), the target enzyme for this antimetabolite; and dump, the substrate that competes with fdump for binding to tmp synthetase. as little as 0.02 pmol of fdump can be quantitated with a competitive ligand binding assay by using homogeneous lactobacillus casei/mtx tmp synthetase as a binding protein. a new binding ... | 1979 | 108681 |
| separation and identification of pteroylpolyglutamates by polyacrylamide gel chromatography. | | 1979 | 109018 |
| the use of triazine inhibitors in mapping the active site region of lactobacillus casei dihydrofolate reductase. | | 1979 | 109047 |
| 5 (alpha-bromoacetyl)-2'=deoxyuridine 5'-phosphate: a mechanism based affinity label for thymidylate synthetase. | | 1979 | 109088 |
| interaction of dihydrofolate reductase from amethopterin-resistant lactobacillus casei with cibacron blue, blue dextran, and affi-gel blue. | | 1979 | 109449 |
| folate analogues altered in the c9-n10 bridge region: 11-thiohomofolic acid. | the synthesis of 11-thiohomofolic acid (2) has been accomplished by an unambiguous procedure. reaction of 1-chloro-4-[p-(carbomethoxy)thiophenoxy]-2-butanone (10) with hydroxylamine under carefully controlled conditions gave the corresponding oxime 33. conversion of this oxime to 1-phthalimido-4-[p-(carbomethoxy)thiophenoxy]-2-butanone oxime (4) was carried out by its reaction with potassium phthalimide using crown 18 ether as a catalyst. hydrazinolysis of compound 4 gave 1-amino-4-[p-(carbometh ... | 1979 | 109615 |
| methotrexate analogues. 12. synthesis and biological properties of some aza homologues. | methotrexate analogues, in which an additional nitrogen atom is inserted between the phenyl ring and the carbonyl group of the side chain, were prepared by photochemical methods. the compounds were less inhibitory toward dihydrofolate reductase and thymidylate synthetase derived from lactobacillus casei than was methotrexate. they were also less cytotoxic against human lymphoblastic leukemia cells (ccrf-cem). in vivo against l-1210 leukemia in mice, the aza homologue of methotrexate showed signi ... | 1979 | 109616 |
| synthesis of aza homologues of folic acid. | folic acid analogues containing an additional nitrogen atom between the phenyl ring and the carbonyl group of the side chain were synthesized. none of the compounds showed significant inhibitory activity against human lymphoblastic leukemia cells (ccrf-cem) in culture or against lactobacillus casei (atcc 7469) growth. against l1210 leukemia in mice, the aza homologue of folic acid, 4, and the aspartic acid analogue, 14, showed no increase in life span over control animals. these compounds were m ... | 1979 | 109617 |
| tissue folacin stores in rats measured by radioassay. | | 1979 | 109843 |
| immunological cross-reactivity of oral non-streptococcal bacteria with mammalian tissue. | the presence of cross-reacting antigens between oral non-steptococcal bacteria and human and monkey tissue was investigated by indirect immunofluorescence. rabbit antisera, prepared against 22 oral bacteria, were incubated with cryostatcut sections of heart, skeletal muscle, brain cord, liver, kidney, and skin. a cell wall antigen of lactobacillus casei was shared with neuroglial brain cells, and an antigenic component of propionibacterium acnes was shared with kidney glomeruli. tissue-reactive ... | 1979 | 110702 |
| coupling of energy to folate transport in lactobacillus casei. | lactobacillus casei cells can accumulate folate to an intracellular concentration in excess of 500 mum and to concentration gradients (relative to the extracellular compartment) of several thousand-fold. maximum rates of folate transport are achieved rapidly (t(1/2) < 1 min) after the addition of glucose to energy-depleted cells and occur at intracellular adenosine 5'-triphosphate concentrations above 625 mum. the rate of folate transport and the adenosine 5'-triphosphate content of cells are bo ... | 1979 | 110791 |
| increased synthesis of ribonucleotide reductase after deoxyribonucleic acid inhibition in various species of bacteria. | the specific activity of ribonucleotide reductase was found to increase significantly after deoxyribonucleic acid inhibition in seven species of bacteria investigated. this group of bacteria includes species with b12-dependent ribonucleotide reductase as well as some with an escherichia coli-type ribonucleotide reductase. | 1979 | 110794 |
| multivariate analysis and quantitative structure-activity relationships. inhibition of dihydrofolate reductase and thymidylate synthetase by quinazolines. | quantitative structure-activity relationships (qsar) have been established for the inhibition of dihydrofolate reductase and thymidylate synthetase by 2,4-diaminoquinazoline-glutamic acid analogues. for dihydrofolate reductase from both human acute lymphocytic leukemia cells and murine l1210r cells, qsar's obtained with 50 quinazolines were similar. on the other hand, for the inhibition of thymidylate synthetase from murine l1210s cells and from lactobacillus casei, qsar's formulated on the basi ... | 1979 | 110930 |
| synthesis of 5-selenium-substituted uracil derivatives. inhibition of thymidylate synthetase by 5-hydroseleno-2'-deoxyuridylate. | 5-selenium-substituted derivatives (diselenides) or uracil, 2'-deoxyuridine, and 2'-deoxyuridylic acid were synthesized via the addition of methyl hypobromite to the 5,6 double bond, followed by reaction of the adducts with sodium diselenide. the physical and chemical properties of these compounds (including their facile reduction by dithiothreitol and rapid reoxidation) were similar to those of the corresponding 5-sulfur analogues. 5-hydroseleno-2'-deoxyuridylic acid was as potent as 5-mercapto ... | 1979 | 110931 |
| the interaction of ligands with enzymes. a starting point in drug design. | the problem of inhibiting a specific enzyme of a pathogen without inhibiting the corresponding enzyme of the host is one which has intrigued medicinal chemists for years. while it is easy to find potent inhibitors of purified enzymes transforming these inhibitors into effective drugs, it still is a very poorly understood business. this report discusses studies with two enzymes, papain and dihydrofolate reductase, and the nonspecific (phi and mr correlated) interaction of ligands with them. the q ... | 1979 | 111968 |
| thymidylate synthetase catalyzed exchange of tritiumfrom [5-3h]-2'-deoxyuridylate for protons of water. | thymidylate synthetase catalyzes an exchange of tritium of [5-3h]dump for protons of water in the absence of ch2-h4folate. the turnover number for this reaction is some 45,000-fold lower than that of dtmp formation and km is 1.2 x 10(-5) m, similar to the dissociation constant of the enzyme-dump complex determined by equilibrium dialysis. the presence of 4 mm folate has no effect on vmax but results in a decrease in the km of dump to a value close to that in the normal enzymic reaction. the exch ... | 1979 | 113030 |
| quinazoline analogues of folic acid as inhibitors of thymidylate synthetase from bacterial and mammalian sources. | | 1979 | 113660 |
| nuclear magnetic resonance studies of the binding of trimethoprim to dihydrofolate reductase. | the resonances of the aromatic protons of trimethoprim [2,4-diamino-5-(3',4',5'-trimethoxybenzyl)pyrimidine] in its complexes with dihydrofolate reductases from lactobacillus casei and escherichia coli cannot be directly observed. their chemical shifts have been determined by transfer of saturation experiments and by difference spectroscopy using [2',6'-2h2]trimethoprim. the complex of 2,4-diamino-5-(3',4'-dimethoxy-5'-bromobenzyl)pyrimidine with the l. casei enzyme has also been examined. at ro ... | 1979 | 114205 |
| 5-fluoro-2'deoxyuridine 5'-(p-azidophenyl phosphate), a potential photoaffinity label of thymidylate synthetase. | 5-fluoro-2'-deoxyuridine 5'-(p-azidophenyl phosphate) (1), a potential photoaffinity labeling reagent for thymidylate synthetase from a methotrexate-resistant strain of lactobacillus casei, has been synthesized and characterized. uv254 irradiation of mixtures of thymidylate synthetase with 1, containing 14c-labeled phenyl and 3h-labeled pyrimidine rings, in the presence of excess 5,10-methylenetetrahydrofolate, the cofactor for the reaction, produced two complexes, separable from the native enzy ... | 1979 | 114656 |
| 5-[(4-methyl-1,2,3,4-tetrahydroquinoxalyl)methyl]-2'-deoxyuridine 5'-phosphate: an analogue of a proposed intermediate in thymidylate synthetase catalysis. | in a study of the sequence steps involved in the mechanism of thymidylate synthetase catalysis, 5-[(n-methyl-piperazinyl)methyl]- (5) and 5-[(4-methyl-1,2,3,4-tetrahydroquinoxalyl)methyl]-2'-deoxyuridine 5'-phosphate (6) were synthesized. compound 6 has high affinity for the lactobacillus casei enzyme (ki = 0.75 microm, ki/km - 0.23), which is 50 times stronger than that of the piperazinyl derivative 5. compound 6, a possible multisubstrate inhibitor, is an analogue of a proposed intermediate in ... | 1979 | 114659 |
| 5-cyano-2'-deoxyuridine 5'-phosphate: a potent competitive inhibitor of thymidylate synthetase. | the 5'-phosphate (1) of the antiviral nucleoside 5-cyano-2'-deoxyuridine was synthesized and evaluated for inhibition of thymidylate synthetase purified from methotrexate-resistant lactobacillus casei. compound 1 was a potent competitive inhibitor with a k1 of 0.55 microns. irreversible enzyme inhibition by this compound could not be detected. | 1979 | 114660 |
| thymidylate synthetase and 2'-deoxyuridylate form a tight complex in the presence of pteroyltriglutamate. | thymidylate synthetases of human and bacterial origin form a tightly bound complex with the substrate dump in the presence of pteroyltriglutamate. this complex and the weaker enzyme . dump binary complex can be isolated and conveniently assayed by nitrocellulose disc filtration using [6-3h]dump as the radioactive ligand. intact thymidylate synthetase . dump . pteroyltriglutamate complex can be obtained by gel filtration chromatography on sephadex g-25, but the binary enzyme . dump complex dissoc ... | 1979 | 115883 |
| n-benzoyl derivatives of amino acids and amino acid analogs as growth inhibitors in microbial antitumor screen. | twenty-seven n-benzoyl derivatives of amino acids and amino acid analogs were prepared and tested for growth-inhibitory activity in a microbial antitumor screen. of these, 19 showed some inhibitory capacity, from a modest 13% to a potent 96% at 1 mg/ml. the activities of the "modest" inhibitors were comparable to those of most inhibitory chloracetyl and trifluoroacetyl derivatives reported earlier. the intermediate inhibitors were as active as n-chloroacetyl-beta-hydroxy-d-norleucine isomer b, t ... | 1979 | 117094 |
| essential arginyl residues in thymidylate synthetase from amethopterin-resistant lactobacillus casei. | | 1979 | 117827 |
| pentitol metabolism in lactobacillus casei. | strains of lactobacillus casei capable of growing on either ribitol or xylitol carry out a heterolactic fermentation producing ethanol, acetate, and a mixture of d- and l-lactate. following conversion of the pentitols to ribulose 5-phosphate or xylulose 5-phosphate via enzymatic steps unique to these organisms, the intermediate products are further metabolized by enzymes of the pentose pathway. the initial enzymes of the pathway, i.e., pentitol:phosphoenolypyruvate phosphotransferase and penitit ... | 1979 | 118163 |
| inhibition of dihydrofolate reductases by derivatives of 2,4-diaminopyrroloquinazoline. | | 1979 | 118761 |
| the role of liver passage for conversion of pteroylmonoglutamate and pteroyltriglutamate to active folate coenzyme. | in an attempt to clarify the possible site of conversion of folates to active methylated coenzyme forms mono- and triglutamate was injected rapidly into the portal vein of dogs. samples of blood were removed at various intervals from catheters placed in the portal vein, the hepatic vein and the femoral artery for assay carried out both with l. casei, s. faecalis and liquid scintillating counting. unreduced monoglutamates were extracted in the liver, immediately converted to methyltetrahydrofolat ... | 1979 | 118944 |
| lipoquinones of some spore-forming rods, lactic-acid bacteria and actinomycetes. | the respiratory quinones of 73 strains of gram-positive bacteria including spore-forming rods, lactic-acid bacteria and actinomyctes were examined. menaquinones with seven isoprenoid units (mk-7) were the main quinone type found in representatives of the genus bacillus and in sporolactobacillus inulinus. however, a strain of b. thuringiensis produced mk-8 in addition to mk-7, and strains of b. lentus and b. pantothenticus appeared to produce mk-9 and mk-8, respectively, with no mk-7. in the clos ... | 1979 | 119033 |
| 5-(alpha-bromoacetyl)-2'-deoxyuridine 5'-phosphate: an affinity label for thymidylate synthetase. | 5-(alpha-bromoacetyl)-2'-deoxyuridine 5'-phosphate (1) is an active-site-directed irreversible inhibitor of thymidylate synthetase from lactobacillus casei. analysis of the rate of inactivation of the enzyme in the presence of substrate confirmed the intermediate formation of a reversible enzyme-inhibitor complex. | 1979 | 119854 |
| vitamin b2 activity of 7,8-dimethyl-10-(2,3,4-trihydroxy-4-formylbutyl)isoalloxazine in lactobacillus casei. | the microbial activities of vitamin b2-aldehyde and vitamin b2-acid, produced by schizophyllum commune, a basidiomycete, were studied. lactobacillus casei atcc no. 7469 was used as a test microorganism. b2-aldehyde exhibited a good response curve in the growth of l. casei. b2-acid had neither a stimulatory nor an inhibitory effect on the growth. when b2-aldehyde was incubated with the homogenate of l. casei, it was converted to riboflavin. the flavin formed from b2-aldehyde by the homogenate not ... | 1979 | 120425 |
| denaturation of thymidylate synthetase from amethopterin-resistant lactobacillus casei. | the effects of various concentrations of urea and guanidine hydrochloride on enzyme activity and on subunit association were determined. incubation of thymidylate synthetase with buffered solutions of 3m to 3.5m guanidine hydrochloride or 5 m to 6 m urea resulted in the loss of about 90% of the enzyme activity. under these denaturing conditions a red shift of the fluorescence emission maximum from 340 nm to 351 nm was observed together with a significant decrease in the relative fluorescence int ... | 1979 | 121920 |
| anthrax bacillus - a preliminary report on its isolation and characterisation from soils in sri lanka. | | 1978 | 122072 |
| quenching of thymidylate synthetase fluorescence by substrate analogs. | | 1975 | 125086 |
| molecular aspects of the mechanism of action of 5-fluorodeoxyuridine. | | 1975 | 127539 |
| variations in melanin and riboflavin content of amphibian liver under the influence of reserpine and amphetamine. | by means of paper chromatography, lactobacillus casei test and the staining method with the feulgen reaction, the effects of reserpine and amphetamine on riboflavin and melanin were studied in the liver of triturus cristatus. it was demonstrated that the concentrations of both melanin and riboflavin can be altered by the influence of these drugs. from the results obtained it is suggested that riboflavin shows a correlation with the density of melanin. | 1976 | 132047 |
| antifolate studies. activities of 40 potential antimalarial compounds against sensitive and chlorguanide triazine resistant strains of folate-requiring bacteria and escherichia coli. | as part of the search for new antimalarial drugs, a screening program was developed using sensitive and chlorguanide triazine (cgt, cycloguanil) resistant strains of the folate-requiring bacteria, streptococcus faecium durans, lactobacillus casei, and pediococcus cerevisiae. the activities of 40 compounds have been studied against these strains and escherichia coli. observations have been made on the points of 50% growth inhibition, the fold increase of resistance shown to each compound by the r ... | 1977 | 137981 |
| a prophylactic trial of iron and folic acid supplements in pregnant burmese women. | hemoglobin (hb) concentration, serum iron level, iron binding capacity and blood folate (lactobacillus casei) activity were determined in 310 unselected pregnant burmese women. hb concentration was less than 11 g/dl in 72% of the women; the serum iron level was less than 50 mug/dl in 33%; serum folate activity was less than 3ng/ml in 13%; and red cell folate activity was less than 100 ng/ml in 17% of the women. ninety-six of the women in our study were randomly divided into four groups, treated ... | 1976 | 138664 |