| serologic properties of strains of cl. perfringens isolated from the intestinal contents of healthy subjects. | a study was made of the quantitative content in the intestine of c1. perfringens strains in 6 healthy persons who stayed in a hermetically sealed space for 1 month and for 1 year. c1. perfingens strains were isolated from the fecal samples of each of the volunteers at various periods of the trial. a total of 570 strains of c1. perfringens of type a with anticellular sera obtained to the strains of various serological groups were studied. serological properties of c1. perfringens strains of type ... | 1976 | 8938 |
| purification and properties of an enzyme catalyzing the splitting of carbon-mercury linkages from mercury-resistant pseudomonas k-62 strain. i. splitting enzyme 1. | an enzyme (s-1) which catalyzes the splitting of carbon-mercury linkages of organomercury compounds was purified about 24-fold from the cell-free extract of mercury-resistant pseudomonas k-62 strain by treatment with streptomycin, precipitation with ammonium sulfate, and successive chromatography on sephadex g-150, deae-sephadex, and deae-cellulose. a purified preparation of the enzyme showed a single band on polyacrylamide gel electrophoresis, and was colorless. the molecular weight of the enzy ... | 1976 | 9382 |
| epidemiological studies of streptococcus pneumoniae in infants: methods of isolating pneumococci. | a prospective study of the natural history of pneumococcal infection, which involves serial culture studies in healthy infants from 6 weeks of age onward, is in progress in our laboratory. this report describes results of a comparison of several methods for the isolation and identification of streptococcus pneumoniae from the nasopharynges and throats of these infants. sheep blood agar, sheep blood agar with gentamicin sulfate (gentamicin agar), and mouse inoculation with 4-h broth cultures were ... | 1977 | 16032 |
| transfer of drug-resistance-plasmids in mixed cultures of staphylococci. | transfer of pen- and chl-plasmids does not only occur between strains of staph, aureus but also betwen strains of staph, aureus and staph, epidermidis. in staph, aureus, the frequency of transfer of a tet-plasmid is less frequent than the transfer of pen- and chl-plasmids. lysogenization of the donor strain by a sero-group-b-phage has no influence on the frequency of transfer. the transfer is not inhibited by gamma-globulin. gamma-globulin inhibits unspecifically phage adsorption and also the tr ... | 1977 | 66824 |
| genetic regulation of udp-glucuronosyltransferase induction by polycyclic aromatic compounds in mice. co-segregation with aryl hydrocarbon (benzo(alpha)pyrene) hydroxylase induction. | induction of hepatic 4-methylumbelliferone udp-glucuronosyltransferase (ec 2.4.1.17) by polycyclic aromatic compounds, such as 3-methylcholanthrene or beta-naphthoflavone, occurs in c57bl/6n, a/j, pl/j, c3heb/fej, and balb/cj but not in dba/2n, au/ssj, akr/j, or rf/j inbred strains of mice. this pattern of five responsive and five nonresponsive mouse strains parallels that of the ah locus, which controls the induction of aryl hydrocarbon (benzo[alpha]pyrene) hydroxylase (ec 1.14.14.2). induction ... | 1977 | 67114 |
| fine specificity of regulatory t cells. ii. suppressor and helper t cells are induced by different regions of hen egg-white lysozyme in a genetically nonresponder mouse strain. | we have examined the ability of two purified peptide fragments derived from hen (chicken) egg-white lysozyme (hel); n-terminal, co-terminal peptide (a.a. 1--17:cys 6--cys 127:120--129) and mixed disulfide lii peptide (lii) (a.a. 13--105) to induce antigen-specific suppression or help in b10 (h-2b) nonresponder and b10.a (h-2a) responder mice. an anti-hel primary in vitro antibody response can be obtained in either strain by stimulation with hel coupled to erythrocytes (rbc). preimmunization with ... | 1979 | 88500 |
| [antigenic and biological characteristics of the a (h1n1) strains that caused the 1977--1978 epidemic]. | by the antigenic specificity of the surface subunits, hemagglutinin and neuraminidase, the influenza virus strains a (h1n1) isolated in 1977--1978 were related but not identical to the a (h1n1) strains circulating in 1950--1952. the a/fm/1/47 strain differed from the a/england/51, a/pan/52 strains and a/ussr/090/77 strain by its antigenic relations with the a/netherland/56 and a/denver/57 strains. biologically, the new a/h1n1/77 strains were similar to the reference strains circulating in 1947-- ... | 1979 | 92100 |
| [electron microscopic study of bacillus subtilis mutants differing in the serine proteinase activity and spectrum]. | vegetative cells and spores of the colonial morphological mutants of bacillus subtilis a-50 were studied by electron microscopy. the ultrastructure of vegetative cells from both asporogenic colonial-morphological mutants and those which were capable of forming spores in the presence of high concentrations of nitrogen and carbon sources with a decreased activity and a modified spectrum of serine proteases differed from the parent strain by the presence of a microcapsule, the uneven thickness of a ... | 1978 | 100670 |
| structural determination of 'cord factor' from a corynebacterium diphtheriae strain by a combination of mass spectral ionization methods: field desorption cesium cationization and electron impact mass spectrometry studies. | the composition and structure of a preparation of 'cord factor' (di-beta-hydroxy acyl trehaloses) from corynebacterium diphtheriae have been determined by a combination mass spectral ionization methods. the methods were tested by means of synthetic 6,6'-dicorynomycolate of alpha-d-trehalose prior to their use on natural products. the determination of the molecular weight of the components and the estimation of their relative abundance in the natural mixture were made by field desorption mass spe ... | 1978 | 106902 |
| [emotional reactivity and neurovegetative balance in the rat (author's transl)]. | it has been shown in male rats of two albino strains, wistar and sprague-dawley, that differences in emotional reactivity were related to physiological differences (bernet and denimal, 1978). particularly the resting heart rate was slower in the more emotionally reactive rats. it has been suggested that emotional reactivity is linked with a certain neurovegetative balance. this possibility was investigated in twelve rats of each strain by means of differential blockade of the autonomic nervous s ... | 1979 | 108736 |
| genetic relatedness between streptomycin-producing and non-producing strains of streptomyces griseus, studied by means of dna-dna hybridization. | dna-dna hybridization was studied in order to determine the genetic relatedness between a streptomycin-producing and a non-producing mutant of streptomyces griseus. the latter strain of short vegetative life cycle had been developed from the streptomycin-producing strain by means of nitrogen mustard treatment. since the two strains differ in several features, we were prompted to examine the sequence homology between their dnas. hybridization experiments carried out with the membrane filter metho ... | 1978 | 112814 |
| [staphylococcus aureus phage induction by and sensitivity to ultraviolet rays]. | the main characteristics of the phid convertant phage of staphylococcus aureus have been studied, including the quantitative study of the induction of bss (phid) strain by u.v., of the multiplication of the inducted phage, and of its sensitivity to the u.v. irradiation. | 1975 | 126464 |
| development of two inbred strains of rats and characteristics of their skin reactions. | two inbred strains of rat (donryu and sprague-dawley strains) were developed. the skin reactions of these strains immunized with m. tuberculosis, hen egg albumin (ova) or hen egg lysozyme and challenged with the purified protein derivative (ppd) or each antigen were even and uniform. the donryu strain showed a typical arthus reaction with petechiae and edema and a negligible delayed skin reaction, whereas the sprague-dawley strain showed a poor arthus reaction and a typical delayed skin reaction ... | 1976 | 140679 |
| the restriction endonucleases in bacillus amyloliquefaciens n strain. substrate specificities. | two species of restriction endonuclease were isolated by gel filtration and deae-cellulose chromatography from a cell-free extract of bacillus amyloliquefaciens (b. subtilits) n strain; a lower molecular weight endonuclease (endonuclease r.bamni) and a higher molecular-weight one (endonuclease r.bamnx). both of them required only mg2+ for their activities. endonuclease r.bamnx introduced a larger number of site-specific scissions in excherchia coli phage lambda dna that endonuclease r.bamni did. ... | 1976 | 182257 |
| use of elution marker for the intratypic characterization of poliovirus strains. | elution marker was used for intratypic characterization of poliovirus strains with al(oh)3 gel as adsorbent. the virion suspensions to be tested were partially purified by chromatography and labelled with 32p. in the labelled preparations of wild virus strains practically all radioactivity was found in virus-specific bond, whereas in those of the vaccine strains and isolates of vaccine origin a considerable, but variable, proportion of the activity was bound to residual cell components. for this ... | 1976 | 193364 |
| susceptibility of clinical isolates of cytomegalovirus to human interferon. | human cell culture-derived interferon was shown to inhibit human cytomegalovirus in vitro. a prototype strain, davis, and six clinical isolates of cytomegalovirus were tested. all six isolates showed uniform susceptibility to interferon, exceeding that of the davis strain by two- to fourfold. the latter virus was found to be 32 to 4 times less susceptible than the sensitive indicator, vesicular stomatitis virus. however, the laboratory finding of susceptibility to an antiviral material may not r ... | 1977 | 193440 |
| persistence of both human cytomegalovirus and epstein-barr virus genomes in two human lymphoblastoid cell lines. | by dna-dna reassociation kinetic analysis, less than one genome equivalent per cell of human cmv-dna was found in two lymphoblastoid cell lines, one derived from the peripheral blood of a congenitally infected male infant at the age of 21 months (d4 cell line), the other obtained by co-cultivation of lethally x-irradiated cells from the 9-month lymphoblastoid cell line previously described by joncas et al. (1975) with cord blood leukocytes of a female newborn (m1 cell line). human cmv antigens c ... | 1978 | 211195 |
| experimental mixed cns infections in mice caused by three ixodes ricinus transmitted arboviruses. | approximately 12-day-old mice were infected intracerebrally with tick-borne encephalitis (tbe) virus (strain hypr), unkuniemi virus (strain by e50) and tribec virus, as single virus inoculations, coinfections with two or three viruses, and sequential infections with two or three viruses at 24-hour intervals. the effect of mixed infections on mortality, morbidity and average survival time was recorded. the main findings were that: 1. some mixed infections with tbe and uuk viruses reduced the mort ... | 1978 | 214993 |
| biochemical and immunological properties of ribonucleic acid-rich extracts from francisella tularensis. | ribonucleic acid (rna)-rich extracts derived from the attenuated strain of francisella tularensis (strain lvs) protected swiss mice against lethal challenge with f. tularensis strain 425 but not against strain schu s4. no killed preparation, including an rna-rich extract from schu s4 itself, offered protection against strain schu s4 in contrast to the high level of protection offered against this strain by vaccination with live strain lvs. the protective activity observed against strain 425 was ... | 1975 | 237834 |
| [antimicrobial susceptibility patterns of clinical isolates of pseudomonas cepacia (author's transl)]. | the yearly changes of relative frequency of glucose-nonfermentative gram-negative bacilli except for p. aeruginosa isolated from various clinical specimens over the past 5 years were studied. acinetobacter anitratum was the most commonly encountered strain and p. maltophilia and p. putida were also frequently encountered during 1974 through 1977. in 1978, p. cepacia became a significantly predominant strain, which was 44.6% of all nonfermentative gram-negative bacilli excluding p. aeruginosa iso ... | 1979 | 259663 |
| bcg as active immunotherapy in children with acute lymphoblastic leukemia in longstanding remission: positive effects on remission duration and immunologic parameters. | currently at the university of florida, 22/45 children and adolescents are long-term survivors in complete sustained remission of standard chemotherapy regimens and central nervous system prophylaxis. all such therapy was discontinued in these survivors at 36 months after diagnosis and they were given monthly inoculations of bcg of the tice strain by tine technique. 19/22 of bcg-treated patients remain in remission for 12 to 44 + months after cessation of chemotherapy. 1/22 has suffered relapse. ... | 1978 | 276382 |
| age-dependent production of iga and igm autoantibodies against igg2a in a colony of 129/sv mice. | although much of the basic immunological work has been done with mice, little is known about anti-igg autoantibodies in this species. dresser (1, 2) has reported the occurrence, in cba mice, of anti-igg antibody (ab)(1) detected by a hemolytic-plaque assay after stimulation with endotoxin or immunization against sheep erythrocytes. igm rheumatoid factor has also been described in various strains of mice with a systemic lupus erythematosus-like disease (3). recently, we have tried to induce anti- ... | 1979 | 312900 |
| responses of tumors induced in inbred guinea pig strain jy=1 and strain hartley/f to bcg. | a transplantable fibrosarcoma induced in inbred jy-1 guinea pig strain by 3-methylcholanthrene (mca) and designated j4, an allotransplantable subline of j4 (jh4) which was obtained by the transplantation of j4 into the inbred hartley/f guinea pig strain and maintained by passages in this strain, and a syngeneic liposarcoma h10 induced in a hartley/f guinea pig by mca were tested for their immunotherapeutic response with bcg. the growth of j4 and h10 tumors was suppressed in most of the animals w ... | 1977 | 320348 |
| [agglutination reaction of t. cruzi, t. cruzi like strains, t. rangeli and t. conorhini with soja hispida lectin and aaptos papillata protectin (author's transl)]. | protectin from the sponge aaptos papillata (keller) was used in the characterization of five strains of t. cruzi (venezuela, guatemala, y. brasilien, peru, wien) and six t. cruzi like strains (triatoma, maryland, itmap 943, fh4, fh5, ln). based upon their membrane receptors, these t. cruzi and t. cruzi like isolates could be differentiated from rangeli (venezuela strain) and t. conorhini (hawai strain) by agglutination reaction to the proctectin. furthermore, after pronase treatment t.rangeli co ... | 1977 | 324052 |
| purification of protein a, an outer membrane component missing in escherichia coli k-12 ompa mutants. | outer membrane materials prepared from an escherichia coli ompa (tolg) strain do not contain one of the major outer membrane proteins found in ompa+ strains. this protein has been purified in high yield from detergent-solubilized cell envelope material prepared from an ompa+ strain by preparative electrophoresis in polyacrylamide gels containing sodium dodecyl sulfate. the purified protein is homogeneous in three electrophoretic systems, contains 2 mol of reducing sugar/mol of peptide and has al ... | 1977 | 328056 |
| effect of the rela gene on derepression of amino acid biosynthetic enzymes in growing escherichia coli depends on the pathway being derepressed. | derepression of an enzyme in the arginine biosynthetic pathway, but not of an enzyme in the tryptophan biosynthetic pathway, is inhibited during the stringent response produced by a partial deprivation of valyl transfer ribonucleic acid in a rel+ strain. in contrast, derepression of the tryptophan biosynthetic enzyme, but not of the arginine biosynthetic enzyme, was inhibited during the relaxed response produced in an isogenic rela strain by the partial deprivation of valyl transfer ribonucleic ... | 1977 | 334732 |
| directed integration of an f' plasmid by integrative suppression: isolation of plaque forming lambda transducing phage for the dnac gene. | a new approach for isolation of a plaque forming lambda specialized transducing phage is described. it consists of directed transposition of an f' plasmid into the gal region of a dnaats gale- escherichia coli strain by integrative suppression and deletion of the chld region in order to shorten the distance between the marker of interest on the f' and the prophage serving to prepare an lft1 lysate. an f' danc+thr+ plasmid was used here and lambdadthr and lambdaddnac phages were isolated. in addi ... | 1977 | 337125 |
| effect of dihydroxymethyl furatrizine on cell division of escherichia coli. | antibacterial activities of 3-di(hydroxymethyl) amino-6[2-(5-nitro-2-furyl)vinyl]-1,2,4-triazine, (dihydroxymethyl furatrizine) were investigated using mutant strains of escherichia coli lacking repair systems for dna damage, i.e. pola, uvra, uvra, uvrc, reca, recb, recc and uvrareca. all of the mutant strains were more sensitive to the drug than the parent sgrains, as was the case with the sensitivity to uv-irradiation. these results indicate that the drug acts lethally on sensitive bacteria by ... | 1977 | 339039 |
| detection of mutagens produced by fungi with the salmonella typhimurium assay. | forty-one fungal isolates (one isolate per species) representing common plant pathogens and food crop contaminants were grown on sterile, polished rice and assayed for mutagenic activity in the salmonella typhimurium-microsome system. initially, single doses of aqueous and chloroform extracts of the moldy rice were assayed against the ta100 tester strain by incorporating extracts into the growth medium and by applying small quantities on disks placed on the agar surface. suspected activity was e ... | 1978 | 354528 |
| peptidase-deficient mutants of escherichia coli. | mutant derivatives of escherichia coli k-12 deficient in several peptidases have been obtained. mutants lacking a naphthylamidase, peptidase n, were isolated by screening for colonies unable to hydrolyze l-alanine beta-naphthylamide. other mutants were isolated using positive selections for resistance to valine peptides. mutants lacking peptidase a, a broad-specificity aminopeptidase, were obtained by selection for resistance to l-valyl-l-leucine amide. mutants lacking a dipeptidase, peptidase d ... | 1978 | 355237 |
| construction of an l-arginine-producing mutant in serratia marcescens. use of the wide substrate specificity of acetylornithinase. | l-arginine biosynthesis in serratia marcescens sr41 was found to be controlled by (a) feedback inhibition of n-acetylglutamate synthetase and (b) repression of some l-arginine biosynthetic enzymes, and an l-arginine-degrading system was found to exist. accordingly, an l-arginine-producing mutant (aru argr arga) of s. marcescens sr41 was constructed as follows. a mutant incapable of l-arginine utilization (aru) was obtained from the wild strain. subsequently, from the lysine auxotroph (lysa) of a ... | 1978 | 361732 |
| [characteristics of a strain of c. albicans resistant to polyene antibiotics]. | it was found that a resistant strain r2 of c. albicans obtained as a result of passages on media containing increasing concentrations of amphotericin b differed from the initial strain by its lower pathogenicity. treatment of the infection caused by the resistant strain on modeling of candidiasis in mice was not successful. the decrease in the average life span of the mice infected with the resistant strain r2 and treated with amphotericin b was lower than that in the control animals and such in ... | 1979 | 389154 |
| the cellular and humoral immune response after administration to the guinea pig of shigella flexneri 2a t32--istrati vaccinal strain by different routes. | | 1978 | 395927 |
| escherichia coli k-12 tolf mutants: alterations in protein composition of the outer membrane. | outer membrane materials prepared from three independently isolated spontaneous escherichia coli tolf mutants contained no detectable protein ia. the loss of this protein was nearly completely compensated for by an increase in other major outer membrane proteins, ib and ii. thus, the major outer membrane proteins accounted for 40% of the total cell envelope protein in both tol+ and tolf strains. no changes were found in the levels of inner membrane proteins prepared from tolf strains when compar ... | 1977 | 400794 |
| [transfer of pathogenic activity of a virulent strain of listeria to an avirulent strain]. | the pathogenicity of a virulent strain of listeria monocytogenes was transfered to an avirulent strain by mixing the filtered culture of the pathogenic strain with an exponentially growing avirulent strain. | 1977 | 408037 |
| [comparative characteristics of the peptide maps of the major proteins of influenza viruses type a]. | a comparative study of peptide maps of major proteins of hemagglutinin, nucleoprotein, membrane of influenza a virus strains a/ws/33, a/fm/1/47, a/singapore/1/57, a/ussr/090/77, a/port chalmers/1/73 (mrc-11), was carried out. the greatest differences were observed in the peptide maps of heavy and light chains of hemagglutinin of different serotypes. the peptide maps of nucleoprotein and membrane were more similar. the a/ussr/090/77 strain by peptide maps was close to but not identical with the a ... | 1979 | 433239 |
| prevention of salt-induced hypertension in the dahl strain by 6-hydroxydopamine. | salt-induced hypertension in dahl's genetically hypertensive rat has been attributed to humoral or renal factors. however, a recent study from our laboratory suggested that neurogenic mechanisms contribute to salt-induced increased in hindquarters vascular resistance in dahl salt-sensitive (s) rats. in the present study, we examined the hypothesis that "chemical sympathectomy" with 6-hydroxydopamine (6-ohda) prevents salt-induced hypertension and increased vascular resistance in s rats. hyperten ... | 1979 | 434173 |
| two-dimensional gel electrophoretic comparison of proteins from virulent and avirulent strains of mycoplasma pneumoniae. | the protein composition of the virulent m129 strain of mycoplasma pneumoniae was compared to that of its homologous avirulent strain by the use of standard one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. forty-nine individual m. pneumoniae cell proteins were resolved by this method, and the virulent strain was shown to possess a single high-molecular-weight protein not present in avirulent cells. variability in the resolution of this particular protein in one-dimension ... | 1979 | 457282 |
| experimental hypertension and catecholamine distribution in the rat brain. | hypertension was induced in rats (hebrew university strain) by three different procedures: (1) deoxycorticosterone acetate (doca)--salt treatment; (2) unilateral renal artery clip or (3) chronic salt-loading. noradrenaline (na) and dopamine (da) distribution in different brain areas was assayed following induction of hypertension. na content increased significantly in various areas: the increase of na in the pons-medulla was common to all procedures inducing hypertension. na content increased al ... | 1979 | 466431 |
| [microbial degradation of papaverine (author's transl)]. | a bacterium growing on papaverine as sole carbon and nitrogen source was isolated by incubation of soil with papaverine. the bacterium could be identified as a nocardia strain by morphological and physiological tests. when growing on papaverine, this strain excretes metabolites into the medium. based on the structure of the metabolites 1--9 a degradation pathway is proposed. 1 = 1-(3,4-dimethoxybenzyl)-3,4-dihydro-6,7-dimethoxy-3,4-isoquinolinediol; 2 = 1-(3,4-dimethoxybenzyl)-6,7-dimethoxy-3,4- ... | 1979 | 468108 |
| epididymal and testicular enzymes as monitors for assessment of male antifertility drugs. | since the synthesis and maturational processes of sperm are associated with characteristic alterations in different marker enzyme activities in testes and epididymis, it is possible to monitor these enzymes to investigate whether 3 antispermatogenic agents, win 18 446, alpha-chlorohydrin (ac), and cyproterone acetate (ca), have any characteristic effects on biochemical events associated with spermatogenesis and maturation of sperm; acid, neutral, and alkaline proteinases, particulate and soluble ... | 1979 | 491633 |
| transplantation of azaserine-induced carcinomas of pancreas in rats. | two pancreatic adenocarcinomas which had been induced in wistar/lewis rats by azaserine treatment were transplanted into rats of the same strain by subcutaneous and intraperitoneal injection of minced tumor. subsequently, we have serially transplanted into non-radiated recipients. transplanted tumors have maintained evidence of acinar cell differentiation including the presence of zymogen granules in tumors studied by electron microscopy, and of lipase, amylase and trypsin activity in the supern ... | 1979 | 509403 |
| an attenuated strain of akabane virus: a candidate for live virus vaccine. | an attempt was made to attenuate the high virulent obe-1 strain of akabane virus by adaptation to low temperature. in it the virus was subjected to passage through hmlu-1 cell cultures at 30 degrees c. cloning was carried out on the virus which had undergone 20 passages through these cultures to select a strain adapted to low temperature. finally, ten clones were obtained. as a result, nine strains of clone in which virus replication was poor in hmlu-1 cell cultures at 40 degrees c were obtained ... | 1979 | 537649 |
| characterization of eimeria species. i. isolation and study of pathogenicity of a pure strain of eimeria perforans (leuckart, 1879; sluiter and swellengrebel, 1912). | eimeria perforans was isolated in pure strain by utilizing specific biological characters and specific-pathogen free rabbits. the purity of this strain was demonstrated by measurements of oocysts, derived from a line, started by infection from a single oocyst. the parasite, when inoculated in large numbers, causes a mild disease response for only about two days. | 1979 | 539069 |
| acanthamoeba royreba sp. n. from a human tumor cell culture. | a new species of acanthamoeba was isolated from a culture of an established line of human choriocarcinoma cells. the identification of this strain, originally called the oak ridge strain, and the establishment of a new species for it were based on morphologic, serologic, and immunochemical studies. in general, the structure of the trophozoite did not differ significantly from that of other species of acanthamoeba, except that a body which more closely resembled a centriole than material describe ... | 1978 | 566323 |
| genetically marked rhizobium identifiable as inoculum strain in nodules of soybean plants grown in fields populated with rhizobium japonicum. | the fate of an inoculum strain of rhizobium japonicum was studied using a genetically marked strain i-11o subline carrying resistance markers for azide, rifampin, and streptomycin (i-110 ars). at the time of planting into a field populated with r. japonicum, seeds of soybean cultivars kent and peking were inoculated with varying cell densities of strain i-110 ars. at various times during the growing season, surface-sterilized root nodules were examined for the presence of the inoculum strain by ... | 1978 | 570015 |
| [new antibiotic no. 792 formed by actinomyces bottropensis]. | an actinomycetes strain 792 producing a new antibiotic was isolated under the programme of antitumor antibiotic screening. by its morphological and cultural properties strain 792 was classified as belonging to species actinomyces bottropensis. antibiotic 792 was recovered from the culture fluid of the strain by the extraction method in the form of a crystalline orange substances. lambda max 235, 305, 410 nm (e 1% 1cm 705, 105, 168), m. p. 232-255 degrees (dec), molecular weight 340, c 67 per cen ... | 1977 | 576572 |
| bordetella rhinitis in pigs: serum and nasal antibody response to bordetella bacterins. | the nasal and serum antibody response of two groups of pigs, vaccinated with adjuvant containing formalinized or sonicated bordetella bronchiseptica bacterins was compared with the response of a nonvaccinated group. the tube agglutination test was used to determine agglutinin titers. following vaccination, all pigs were challenged intranasally with the vaccine strain of bordetella, after which the nasal bordetella flora of vaccinated and nonvaccinated pigs was investigated. sera and nasal secret ... | 1978 | 647455 |
| clearance of viable salmonella typhi ty 2 and staphylococcus aureus by the isolated rat liver in the absence of serum factors. | the clearance of s. typhi ty 2 and of a s. aureus strain by the isolated rat liver perfused in vitro with a synthetic serum free perfusate was studied. bacteria were added to the perfusate at the initial concentration of 1x10(8) cells/ml. during perfusions the perfusate was sampled; after 30 min bile and liver samples were obtained and used for viable bacterial counts. after 30 min the amount of bacteria phagocytized greatly differed from one strain to the other: 30% for s. typhi ty 2 and 100% f ... | 1978 | 656193 |
| [variability in the amylolytic thermophilic bacterium, bacillus diastaticus, induced by ultraviolet rays]. | the uv-induced variability of the amylolytic thermophilic bacillus diastaticus 13 was studied. the biosynthesis of amylase was found to very under the action of uv from 2.2 to 158.7% a "plus" variant referred to as the mutant uv 1 was produced at a dose of uv equal to 41.8-10(2) erg/mm2. its further selection without using a mutagen made it possible to select a variant uv 1-25 which surpassed the parent strain by 43.3% in amylase biosynthesis. uv-irradiation produced also two mutants with a low ... | 1978 | 661637 |
| changes in mouse liver superoxide dismutase activity and lipid peroxidation during embryonic and postpartum development. | in inbred mice possessing 'high' and 'low' tissue superoxide dismutase (sod) activity, it was observed that the difference in the sod activities of the liver homogenates during development attains the maximum characteristic of the strain by about the 150th day. subsequently, the sod activity change displays a tendency in contrast with the age and the basic state. in the course of the development, a difference was also observed between the 2 mouse strains in the lipid peroxidation variation. | 1978 | 720503 |
| decreased thyroid function and high plasma prolactin levels in rats of the buffalo strain. | rats of the inbred buffalo strain have previously been reported to be susceptible to thyroiditis, as defined by histology. we have studied the endocrinology of the pituitary-thyroid axis of this strain by making direct measurements of the plasma concentrations of tsh and t4 in untreated, adult buffalo rats of both sexes. plasma prl levels were also measured. all hormone determinations were by ria. in addition, relative thyroid weights were noted and, in many cases, preliminary assessment of thy ... | 1978 | 744034 |
| inhibition of peptidoglycan cross-linking in growing cells of escherichia coli by penicillins and cephalosporins, and its prevention by r factor-mediated beta-lactamase. | the degree of peptidoglycan cross-linking has been studied in growing cells of a dap(-) lys(-) auxotroph of escherichia coli k-12 by following the incorporation of [(3)h]diaminopimelic acid into the lysozyme digestion products of crude, isolated peptidoglycan. the percentage of inhibition of cross-linking increases with increasing concentrations of penicillin g, cephaloridine, and cefuroxime. when the r factor r1drd 19 was introduced into the strain by conjugation, it was found that the type iii ... | 1976 | 773294 |
| reversion of the gal3 mutation of escherichia coli: partial deletion of the insertion sequence. | the gal3 mutation of e. coli is an insertion of a dna sequence, 1,100 base pairs in length, into the operator-promoter region of the galactose operon. this mutation reverts spontaneously to gal+ by excision of the insertion to produce stable, inducible revertants, or by tandem duplications of the gal operon to produce unstable, constitutive revertants. the nature of a third class of revertants, which are stable and constitutive, is the subject of the present study. the stable, constitutive class ... | 1976 | 775285 |
| recombination promoted by superhelical dna and the reca gene of escherichia coli. | when a mixture of superhelical dna (rfi) of phage phix174 am3 and fragments of single-stranded dna from wild-type phix174 was added to spheroplasts of e. coli carrying an amber suppressor, several percent of the progeny phage were recombinant. the yield of wild-type progeny was 10(3) to 10(4) times lower when the fragments came from phix174 am3 or phage g4 am+, or when fragments were absent. fewer recombinants were produced in proportion to the decrease in the fraction of rfi in samples treated ... | 1976 | 792876 |
| chondroitinase-producing bacteria in natural habitats. | a search was undertaken for bacteria which degrade chondroitin sulfate in nature and to find bacteria with a usefully high rate of chondroitinase (chsase) productivity. first, 253 chsase-producing bacteria were obtained from aquatic and land environments in japan by aerobic and anaerobic screening methods. identification according to bergey's manual of determinative bacteriology or bain and shewan (1968) permitted assignment of the majority of the isolates to seven genera, aeromonas, vibrio, fla ... | 1975 | 803822 |
| viral mutation affecting bacteriophage phi 1 development in bacillus subtilis 168. | bacillus subtilis bacteriophage phi 1m, a host-range variant, was isolated after mutagenesis of virulent bacteriophage phi 1. unlike its wild-type antecedent, phi 1m could not form plaques on lawns of b subtilis 168 at 37 c, although it adsorbed to, penetrated, and killed this bacterium. experiments conducted in liquid medium at 37 c showed that b. subtilis 168 cells allowed reduced levels of phi 1m development at low multiplicities of infection, whereas high multiplicity infections of this stra ... | 1975 | 804042 |
| n-nitrosocarbaryl-induced mutagenesis in haemophilus influenzae strains deficient in repair and recombination. | mutagenesis was studied in repair- and recombination-deficient strains of haemophilus influenzae after treatment with n-nitrosocarbaryl (nc). three different strains of h. influenzae carrying mutations affecting excision-repair of uv-induced pyrimidine dimers exhibited normal repair of premutational lesions (as detected by decreased mutation yield resulting from post-treatment dna synthesis delay) and normal nonreplicative mutation fixation. this indicated that neither of these phenomena are cau ... | 1975 | 805362 |
| mutation of bacillus subtilis causing hyperproduction of alpha-amylase and protease, and its synergistic effect. | mutants that had a genetic lesion increasing the production of alpha-amylase and protease simultaneously were isolated from a transformable strain of bacillus subtilis marburg by n-methyl-n'-nitro-n-nitrosoguanidine treatment. these mutants produced two to three times more alpha-amylase and five to 16 times more protease than their parent and were tentatively referred to as ap mutants. as this mutation seems to have occurred at a single gene of the bacterial chromosome and was not located near t ... | 1975 | 809423 |
| experimental trypanosoma cruzi infections in rhesus monkeys. ii. the early chronic phase. | information on the acute and early chronic phases of infection with trypanosoma cruzi in eight rhesus monkeys is reported with particular reference to the pattern of subpatent parasitaemia and serology. xenodiagnosis was superior to animal inoculation and blood culture in its capacity to detect subpatent parasitaemia. each monkey showed an individual, relatively constant pattern of this not related to the nature of the inoculum. levels of indirect fluorescent and indirect haemagglutinating antib ... | 1976 | 824765 |
| vaccination against bovine brucellosis with a low dose of strain 19 administered by the conjunctival route. | eighteen 25 month old cows were vaccinated once either with 10(6) to 10(10) living bacteria of brucella abortus b 19 by the conjunctival route, or with 2.5 to 5 x 10(10) formalin-killed bacteria of the same strain by subcutaneous injection. fifteen days post-vaccination, low but definite agglutination titers were present in sera of cattle receiving 10(10) living bacteria by the conjunctival route, whereas high titers were observed in the control group given subcutaneous injection of killed bacte ... | 1976 | 825014 |
| preservation of a n. meningitidis strain by freezing. a model experiment. | by means of a model experiment the possibility of preserving a n. meningitidis strain by freezing was demonstrated and verified. the results of cultivating the strain after storage at - 20 degrees c, - 15 degrees c and +4 degrees c for 4, 6, 24 and 48 hours were compared. the temperature of - 20 degrees c was found to be the most reliable one for preserving the viability of the n. meningitidis strain. the method of freezing the strain is of practical importance under conditions where no low-free ... | 1976 | 826048 |
| immunogenicity of australian lentogenic strains of newcastle disease virus. | seven-week-old chickens vaccinated oronasally with v4 and ct strains of australian lentogenic strains of ndv were immune to intramuscular challenge with herts 33 and texas gb strains of virulent ndv. vaccination of 1- and 3-week-old chickens with v4 strain by oronasal, conjunctival and drinking water routes using various doses of virus demonstrated that chickens were immune to oronasal challenge with fontana 1083 strain of virulent ndv except where low doses of vaccine virus were administered. o ... | 1977 | 849215 |
| [characteristics of the action of antibiotics in an experimental process caused by cl. histolyticum]. | the cells of cl. histolyticum isolated from the muscular tissue of albino mice infected with the microbe and treated with oxyglucocycline or cephaloridin were similar to each other and the cells of the initial strain with respect to their morphological features, growth character on liquid and solid media and saccharolytic activity. the strains isolated from the animals treated with oxyglucocycline were characterized by lower gelatinolytic, hemolytic, caseinolytic and (to a less extent) collogeno ... | 1977 | 871214 |
| glutarate semialdehyde dehydrogenase of pseudomonas. purification, properties, and relation to l-lysine catabolism. | the lysine-induced glutarate semialdehyde dehydrogenase of pseudomonas was purified to electrophoretic homogeneity from a mutant strain lacking delta-aminovalerate transaminase. the properties of the enzyme, including molecular weight, amino acid composition, electrophoretic behavior, and kinetic features, distinguish it from similar dehydrogenases induced in the same cell strain by hydroxyproline or by glucarate. enzyme induction patterns and the growth behavior of a mutant deficient in glutara ... | 1977 | 914857 |
| regional acetylcholine turnover rates in the brains of three inbred strains of mice: correlation with some interstrain behavioural differences. | the hypothesis that the genetically determined behavioural differences which exist between the inbred mouse strains balb/c, dba/2 and c57bl/6 may be related to differences in acetylcholine metabolism in certain regions of the brain has been tested. in vivo ach turnover rates have been measured in three regions (hippocampus, caudate nucleus and frontal-parietal cortex) of the brains of each strain by following the rate of formation of labelled ach, in these regions, after a pulse intravenous inje ... | 1977 | 922496 |
| selection of c3 alcohols by high and low ethanol selecting mouse strains and the effects on open field activity. | mice of the high-ethanol selecting c57bl/6j strain consume significantly larger amounts of 10% solution of 1,2-propanediol and 1-propanol than the low-ethanol selecting dba/2j strain. both strains uniformly avoid a 10% solution of 1,3-propanediol and 2-propanol. open field activity was tested 30 min after an ip injection of 3 different equimolar doses of each alcohol. an increase in activity was produced in the dba/2j strain by high (0.003 ml/mg) and middle (0.0015 ml/lg) doses of 1,2-propanedio ... | 1976 | 951431 |
| dry aerosol vaccination against newcastle disease: ii. serological response in chicks. | day-old chickens with newcastle disease maternal antibodies are separated in two batches. one batch (s) is vaccinated by liquid spray method with hb1 strain: the other one (ns) is not vaccinated. at 2, 3 or 4 weeks subgroups from s and ns batches are vaccinated with hb1 strain by dry aerosol method. serological controls reveal an important increase of newcastle antibodies within two weeks after dry aerosol vaccination. then a drop of the antibody quantities is observed during weeks 2 to 4 post d ... | 1976 | 955273 |
| catechol oxygenases of pseudomonas putida mutant strains. | investigation of a mutant strain of pseudomonas putida ncib 10015, strain psu-e1, showed that it had lost the ability to produce catechol 1,2-oxygenase after growth with catechol. additional mutants of both wild-type and mutant strains psu-e1 have been isolated that grow on catechol, but not on benzoate, yet still form a catechol 1,2-oxygenase when exposed to benzoate. these findings indicate that either there are separately induced catechol 1,2-oxygenase enzymes, or that there are two separate ... | 1976 | 956121 |
| mycoplasmas and ovine keratoconjunctivitis. | the clinical course of an outbreak of keratoconjunctivitis in housed lambs and their dams was followed. signs were transient generally and became severe in only a small proportion of lambs. the outbreak became most obvious when the lambs were 46 to 55 days old, when 46.9 per cent were affected. mycoplasma conjunctivae isolations, confirmed by comparison with the type strain by biochemical and serological reactions, increased to 62.1 per cent of all eyes swabbed, but no correlation could be demon ... | 1976 | 969200 |
| linkage and dominance characteristics of genes for resistance to organophosphorus acaricides and allelic inheritance of decreased brain cholinesterase activity in three strains of the cattle tick, boophilus microplus. | resistance to the organophosphorus acaricides diazinon, dimethoate and formothion in the biarra (b), mackay (m) and ridgelands (r) strains respectively of the cattle tick b. microplus has been shown previously to be controlled in each strain by a single incompletely dominant autosomal genetic factor. a very similar mode of inheritance of fenthion resistance in strain b has now been demonstrated with no departure in degree of dominance of resistance from the mean value of +0-57 common to these st ... | 1976 | 985225 |
| studies on the effects of furazolidon and p-rosaniline on the kinetoplast of trypanosoma gambiense in mice. | p-rosaniline-sensitive and -resistant strains of trypanosoma gambiense were separately passaged in mice treated with furazolidon. after 10 serial passages in mice, the trypanosomes were found to be resistant to furazolidon when tested in mice. the rate of appearance of ak forms after injection of furazolidon into mice infected with a clone obtained from the p-rosaniline resistant strain by repeated treatment with furazolidon (wrf) was lower than that in mice infected with a clone obtained from t ... | 1976 | 985375 |
| effect of levan on the stages of development of experimental allergic encephalomyelitis. | experimental allergic encephalomyelitis was induced in male guinea pigs of the n13 strain by inoculation of an emulsion of basic protein of myelin with complete freund's adjuvant. the disease was also passively transferred to other animals of the same strain by i.p. injection of sensitized lymphocytes obtained from donors inoculated with the antigenic emulsion eight days previously. daily administration of levan markedly reduced the incidence and severity of the disease in actively sensitized an ... | 1976 | 1017931 |
| [pleiotropic effect of the mutation of streptomycin resistance in micromonospora purpurea var. violacea]. | variation of different features of populations of streptomycin-sensitive and streptomycin-resistant forms of m. purpurea var. violacea, an organism producing gentamicin was studied. the population of the initial streptomycin-sensitive culture was characterized by high homogeneity with respect to the cultural, morphological and some physiological properties. the variation of the features, such as the colony size, pigment formation, auxotrophic mutations, antibiotic production significantly increa ... | 1976 | 1020938 |
| eimeria tenella in chickens: development of resistance to quinolone anticoccidial drugs. | the development of drug resistance by the present houghton strain of eimeria tenella to the quinolones, methyl benzoquate and buquinolate, was found to take place after a single experimental passage. the development of resistance was independent of drug selection pressure and showed cross resistance to other quinolones, but not to amprolium and robenidine. when the weybridge, beltsville and elberfeld strains of e. tenella were compared under similar laboratory conditions, the weybridge and elber ... | 1975 | 1058450 |
| [selection of the influenza virus vaccinal strain by means of crossed protection experiments on mice]. | | 1976 | 1088724 |
| integration of r plasmid rts1 to the gal region of the escherichia coli chromosome. | an r plasmid rts1 was integrated into the gal region of the chromosome of escherichia coli xa-7012 (gale) strain by the directed transposition technique. the integration of the rts1 genome was confirmed mainly by conjugation studies and also by transduction experiments using phage p1. as a result, it was found that the integrated genome contained genes responsible for kanamycin resistance, conjugal transferability, and for autonomous replication. as reported previously, rts1 is temperature sensi ... | 1975 | 1090604 |
| effects of human and rabbit serum on viability, permeability, and envelope lipids of serratia marcescens. | the major action of serum on gram-negative organisms is thought to be on the microbial envelope. we compared the effects of normal human and rabbit serum on the envelope lipids of two strains of serratia marcescens, one sensitive and one resistant to the bactericidal effects of serum. during killing by either serum, the sensitive strain underwent rapid permeability changes coincident with degradation of microbial phospholipids. the resistant strain exhibited none of these effects. the phospholip ... | 1975 | 1091552 |
| levels and turnover of the proteinase b inhibitors in yeast. | the ratio of the proteinase b inhibitors ib1 and ib2 from baker's yeast was shown to depend on the yeast strain by specific immunoprecipitation from boiled yeast extract and subsequent electrophoresis of the heat-dissociated precipitates on polyacrylamide gels. bothe ib1 and ib2 were found, ib2 being by far predominant. saccharomyces carlsbergensis ncyc 74 contained ib1, whereas in saccharomyces cerevisiae x 2180 only ib2 was present. when cells of the latter strain were labelled with [14c] leuc ... | 1975 | 1100120 |
| transduction of a proteus vulgaris strain by a proteus mirabilis bacteriophage. | only proteus vulgaris strain pv127 out of many p. vulgaris, p. morganii and providence strains was transduced to kanamycin resistance by high-frequency transducing variants, 5006mhftk and 5006mhftak, of phage 5006m, a general transducing phage for p. mirabilis strain pm5006. the phages adsorbed poorly to strain pv127 and did not form plaques. the transduction frequency of pv127 by these phages was 5 x 10(-8)/p.f.u. adsorbed. phage 5006m increased the transduction frequencies. abortive transducta ... | 1975 | 1100773 |
| isolation and characterization of mutants with a feedback resistant n-acetylglutamate synthase in escherichia coli k 12. | mutants with a feedback resistant n-acetylglutamate synthase have been isolated from a proa/b, argd, argr strain by screening for proline excretion on minimal medium with arginine. the feedback resistant character of three mutants was transduced into an arga (n-acetylglutamate synthase negative) strain. it was cotransducible with arga at a frequency of greater than 99%. n-acetylglutamate synthase extracted from the three mutants was approximately one hundred times less sensitive to l-arginine th ... | 1975 | 1102931 |
| possibilities of the conjugation process in mycobacteria. | results obtained when studying conjugation in mycobacteria by means of different methods are summarized. the method of conjugation on surface of a solid complete medium was tested with different auxotrophic mutants of different strains of mycobacterium smegmatis. it was not possible to obtain positive results even by means of the above method. this was probably due to unsuitability of the chosen strains of mycobacterium smegmatis. preparation of the donor strain by transfer of the f factor from ... | 1975 | 1104423 |
| enzymatic induction of dna double-strand breaks in gamma-irradiated escherichia coli k-12. | the pola1 mutation increases the sensitivity of e. coli k-12 by killing by gamma-irradiation in air by a factor of 2.9 and increases the yield of dna double-strand breaks by a factor of 2.5. these additional dna double-strand breaks appear to be due to the action of nucleases in the pola1 strain rather than to the rejoining of radiation-induced double-strand breaks in the pol+ strain. this conclusion is based upon the observation that gamma-irradiation at 3 degrees did not affect the yield of dn ... | 1975 | 1105577 |
| catalase, superoxide dismutase, and virulence of staphylococcus aureus. in vitro and in vivo studies with emphasis on staphylococcal--leukocyte interaction. | since oxygen-free polymorphonuclear neutrophils (pmn) cannot kill staphylococcus aureus normally, the usual mechanisms for pmn bactericidal activity probably involve hydrogen peroxide or superoxide. catalase can destroy hydrogen peroxide, and superoxide dismutase breaks down superoxide. experiments were performed to study the influence of these enzymes (which are found in staphylococci) on virulence for mice or on leukocyte-bacterial interaction. 15 staphylococcal strains were injected i.p. into ... | 1975 | 1117067 |
| [variability of the levorin producer, actinomyces levoris krass]. | natural variation of the levorin-producing organism act. levoris, strain 28 was studied with respect to the colony morphology and production of levorin and levoristatin. the population of strain 28 consisted of 3 morphological colony types, the main type amounting to 99.7 percent. the strain variation with respect to production of levorin and levoristatin ranged from 20 to 180 and from 0 to 300 percent respectively as compared to the control. mutant m-28 differing from the initial strain by the ... | 1975 | 1138624 |
| effects of strain of chickens and vaccination with turkey herpesvirus on marek's disease and lymphoid leukosis in breeding stocks. | 1. a total of 3236 females from eight meat-type strains, half of which were vaccinated for marek's disease (md), and 11,193 leghorn females from ten strains, all vaccinated for md, were adventitiously exposed to md and lymphoid leukosis (ll) viruses and observed to 392 and 497 d of age, respectively. 2. in the meat-type birds, vaccination reduced total mortality from 43-4% to 27-1% and mortality due to md from 16-4% to 5-4% but did not affect mortality and ll (2-9% and 3-4%). 3. in the vaccinate ... | 1975 | 1156921 |
| antigenic analysis of three strains of mycoplasma arginini by two-dimensional immunoelectrophoresis. | the occurrence of species-specific and strain-specific antigens in three strains of mycoplasma arginini (g-230, leonis and 23243) was studied by two-dimensional immunoelectrophoresis. approximately 20 antigenic components could be detected in each strain. it was possible to analyze 6 to 7 major and distinct components from each strain by two techniques: "enhancement" where antigen to an additional strain is added to the first phase of the electrophoresis which increases the size of common peaks ... | 1975 | 1167566 |
| histopathological studies of the nervous system tumors in rats induced by n-nitroso-methyl-urea. | histopathological examinations were made on tumors of the nervous system induced in rats of donryu strain by weekly intravenous injections with n-nitroso-methyl-urea (nmu) or by a single administration of nmu through the mothers. a total of 176 neural and nonneural neoplasms were produced in this study. it was suggested that the fetal nervous system of donryu rats was also highly susceptible to the oncogenic effects of nmu. of these tumors produced, those of the peripheral nervous system amounte ... | 1975 | 1180045 |
| effect of prostaglandin e2 on the ductus arteriosus in the newborn rat. an ultrastructural study. | a patent ductus arteriosus (da) was maintained in newborn rats (wistar strain) by administering prostaglandin e2 (pg e2) in doses of 15 micrograms.kg-1 at 30 min intervals up to 300 min after birth. in the control animals, the da was functionally closed 300 min after birth. the lumen was blocked by clustered endothelial cells at various stages of degeneration. elastic membranes of the media had disintegrated into irregular fragments and the smooth muscle cells were contracted. cytoplasm excresce ... | 1992 | 1286100 |
| high-level expression of recombinant protein a in escherichia coli. | a high-level expression plasmid ppa-3 was constructed, which yielded up to 20% of soluble cell proteins as recombinant protein a in e. coli dh5 alpha strain by heat shock induction. the recombinant protein a contained only the five domains of native protein a that bind with the fc part of igg. the molecular weights of the recombinant protein a expressed in e. coli were determined to be 33kda, 32.2kda, 29.5kda and 28.6kda by sds-page and western-blotting. the diversity of the molecular weights ma ... | 1992 | 1297444 |
| a 4-kilobase congo red binding plasmid dna fragment of shigella dysenteriae 1 suppresses the growth and cell differentiation in escherichia coli. | a 4-kilobase congo red binding plasmid dna fragment of pcat 120 of shigella dysenteriae 1 was transferred to an escherichia coli k12 strain by transformation. transformants were unable to grow in any liquid broth medium. electron microscopic studies revealed that the transformants grown on tryptic soy agar were associated in clusters after cell division. normal cell separation among the transformants in comparison with recipient e. coli k12 was only observed when the growth medium was supplement ... | 1992 | 1307443 |
| adaptation of transmissible gastroenteritis virus to growth in non-permissive vero cells. | the cpk cells derived from swine kidney were infected with the attenuated to-163 strain of transmissible gastroenteritis (tge) virus, and fused with uninfected vero cells in the presence of polyethylene glycol. repeated cocultivation of the fused cells with uninfected vero cells rendered the virus to grow in vero cells. the vero cell-adapted virus acquired the ability to infect and produce cytopathic effects in several other non-permissive cell lines of non-porcine origin. no major differences i ... | 1992 | 1309640 |
| preservation of an inbred mouse strain by the storage of frozen embryos: an estimate of the time of occurrence of a serum igg1 deficiency mutation found in mrl-lpr. | | 1992 | 1318459 |
| effect of intestinal bacteria on the virulence of entamoeba histolytica. | the effect on amebal virulence of escherichia coli, clostridium symbiosum and a mixture of lactobacilli was investigated. amebas from hm1 and hk axenic strains were incubated with a single bacterial strain or lactobacilli for short, intermediate, or long periods and analyzed for their erythrophagocytosis, hemolytic activity and cytotoxicity in vitro and hepatic abscesses formation in vivo. it was found that in vitro virulence was enhanced by all studied bacteria in hk9 but not in hm1 strains, wh ... | 1992 | 1340289 |
| identification of the escherichia coli muri gene, which is required for the biosynthesis of d-glutamic acid, a specific component of bacterial peptidoglycan. | the muri gene of escherichia coli, whose inactivation results in the inability to form colonies in the absence of d-glutamic acid, was identified in the 90-min region of the chromosome. the complementation of an auxotrophic e. coli b/r strain by various dna sources allowed us to clone a 2.5-kbp ecori chromosomal fragment carrying the muri gene into multicopy plasmids. the muri gene corresponds to a previously sequenced open reading frame, orf1 (j. brosius, t. j. dull, d. d. sleeter, and h. f. no ... | 1992 | 1355768 |
| sequential infection of tsetse flies with trypanosoma congolense and trypanosoma brucei. | the question whether tsetse flies can be experimentally infected with more than one trypanosome species or strain by sequential feeding was investigated using dna probe technology to identify directly the small numbers of trypanosomes in the fly gut. bloodstream form trypanosomes of trypanosoma congolense or t. brucei ssp. were used for initial infection, followed by sequential feeds using either t. congolense or t. brucei ssp. midgut trypanosome populations were subsequently analysed by hybridi ... | 1992 | 1356306 |
| molecular characterization of cloned variants of coxiella burnetii isolated in china. | to study the molecular properties of coxiella burnetii phase variants we cloned the phase variants of c. burnetii qiyi (cbqy) strain by the red plaque technique. three cloned strains, cbqyic3 (phase i), cbqyiic7 (phase ii) and cbqyiic5 (semirough-phase) were analysed by sds-page, immunoblot assay, plasmid isolation and agarose gel electrophoresis of dna restriction fragments. the results suggest that the unique phase-dependent substance is a lipopolysaccharide and that most protein components of ... | 1992 | 1359769 |
| use of the escherichia coli ssb gene to prevent bioreactor takeover by plasmidless cells. | reactor takeover by plasmidless cells is a major problem encountered when producing proteins from plasmid-borne genes in genetically engineered bacteria. we have approached this problem by deleting the essential ssb gene from the escherichia coli chromosome and placing it on a plasmid. plasmidless cells do not accumulate even after growing such strains under non-selective continuous culture conditions for extended periods of time. other ssb-containing plasmids can be readily introduced into this ... | 1990 | 1366512 |
| purification and some properties of a thermostable metal proteinase produced by thermomicrobium sp. kn-22 strain. | an extreme thermophile that produces a heat-stable proteinase was isolated from hot-spring water and classified as thermomicrobium sp. kn-22 (growth temperature, 50-83 degrees c; and optimum growth temperature, 70 degrees c). the proteinase was purified from the culture broth of this strain by fractionation with ammonium sulfate, chromatography on columns of deae-cellulose and cm-sepharose cl-6b, and hplc on tskgel cm-5pw. the purified enzyme gave a single band on sds-polyacrylamide gel electrop ... | 1991 | 1368714 |
| involvement of recb-mediated (but not recf-mediated) repair of dna double-strand breaks in the gamma-radiation production of long deletions in escherichia coli. | experiments were designed to determine the association between the repair of gamma-radiation-induced dna double-strand breaks (dsb) and the induction of 700-1000 bp long deletions (lac(-)----lac+), base substitutions (leub19----leu+), and frameshifts (trpe9777----trp+) in escherichia coli k-12. over the range of 2.5-20 krad, deletions were induced with linear kinetics, as has been shown for the induction of dsb, while the induction kinetics of base substitutions and frameshifts were curvilinear. ... | 1992 | 1370245 |