J Bacteriol, 1983 Aug, 155(2), 541 - 8 Gene in the major cotransduction gap of the Escherichia coli K-12 linkage map required for the expression of chromosomal resistance to tetracycline and other antibiotics; George AM et al.; In Escherichia coli K-12, amplifiable resistance to tetracycline, chloramphenicol, and other unrelated antibiotics was mediated by at least four spatially separated loci . Tetracycline-sensitive mutants were isolated by Tn5 insertional inactivation of an amplified multiply resistant strain . One of these, studied in detail, showed coordinate loss of expression of all other resistance phenotypes . The Tn5 element in this mutant mapped to 34 min on the E . coli K-12 linkage map . We have designated the locus marA (multiple antibiotic resistance) . Tetracycline-sensitive mutants containing marA::Tn5 regained all resistance phenotypes at frequencies of 10(-8) to 10(-7) upon precise excision of Tn5 . Moreover, a newly described tetracycline efflux system (A . M . George and S . B . Levy, J . Bacteriol . 155:531-540, 1983) was inactivated in tetracycline-sensitive mutants, but recovered in tetracycline-resistant revertants . In merodiploids, F-prime marA+ expressed partial or complete dominance over corresponding mutant chromosomal alleles . Dominance tests also established that a previously amplified host and a mutant marA allele were preconditions for the expression of phenotypic resistances. Antibiotiki, 1983 Apr, 28(4), 262 - 5 {Effect of antibiotic resistance on the appearance of mutants in a culture of Streptomyces cremeus subsp . tobramycini producing an aminoglycoside complex}; Siniagina OP et al.; Possible formation of auxotrophs and changing of the antibiotic production property connected with resistance to antibiotics of different modes of action were studied in Streptomyces cremeus subsp . tobramycini producing the nebramycin complex of 2-desoxystreptamine derivatives . Four hundred and five spontaneous and 1800 gamma-radiation induced antibiotic resistant mutants of the culture were studied . The frequency of the auxotrophs was shown to be increasing . Correlation between formation of strains producing monocomponent aminoglycosides and antibiotic resistance was observed . The frequency of mutants with preferable synthesis of the tobramycin component among strr-, rifr- and rubr-mutants was 3--10 times higher than among the sensitive portion of the population when total selection was used . Therefore, the spontaneous mutation of antibiotic resistance is selective with respect to both isolation of auxotrophs and strains producing separate aminoglycoside antibiotics. J Bacteriol, 1983 Mar, 153(3), 1432 - 8 Evolution of complex resistance transposons from an ancestral mercury transposon; Tanaka M et al.; The molecular interrelationship of a transposon family which confers multiple antibiotic resistance and is assumed to have been generated from an ancestral mercury transposon was analyzed . Initially, the transposons Tn2613 (7.2 kilobases), encoding mercury resistance, and Tn2608 (13.5 kilobases), encoding mercury, streptomycin, and sulfonamide resistances, were isolated and their structures were analyzed . Next, the following transposons were compared with respect to their genetic and physical maps: Tn2613 and Tn501, encoding mercury resistance; Tn2608 and Tn21, encoding mercury, streptomycin, and sulfonamide resistance; Tn2607 and Tn4, encoding streptomycin, sulfonamide, and ampicillin resistance; and Tn2603, encoding mercury, streptomycin, sulfonamide, and ampicillin resistance . The results suggest that the transposons encoding multiple resistance were evolved from an ancestral mercury transposon. Proc Natl Acad Sci U S A, 1983 Feb, 80(4), 1053 - 7 Chimeric plasmid that replicates autonomously in both Escherichia coli and Neurospora crassa; Hughes K et al.; A hybrid pBR322 plasmid (designated pDV1001) containing two functional Escherichia coli antibiotic resistance genes (kanr and camr) and a qa-2+ gene from Neurospora crassa transforms N . crassa qa-2- mutants to qa-2+ with a frequency of ca . 5 X 10(-5) per regenerated spheroplast (ca . 100 transformants per microgram of plasmid DNA) . This plasmid can replicate autonomously without integrating into the N . crassa genome . The autonomously replicating hybrid plasmid was detected in N . crassa transformants by Southern gel hybridizations . DNA from these transformants can be recovered by retransformation back into E . coli aroD recipients and selection for chloramphenicol resistance . These E . coli transformants complement an aroD mutant . The hybrid plasmid DNA present in the E . coli transformants remains unchanged on the basis of DNA restriction enzyme analyses . The original, nonhomokaryotic N . crassa transformants can be maintained on a selective medium, but there is as yet no evidence that the self-replicating plasmid can be transmitted through meiosis . In addition, the self-replicating plasmid often integrates into the N . crassa genome and then is inherited in a generally stable fashion through meiosis . Our findings suggest that this plasmid, or some derivative of it, will prove useful as a routine shuttle vector for cloning genes in N . crassa. Trans R Soc Trop Med Hyg, 1983, 77(1), 59 - 61 Enterotoxigenic Escherichia coli as a cause of paediatric diarrhoea in Ujung Pandang, Indonesia; Maidin MA; The importance of enterotoxigenic Escherichia coli (ETEC) as a cause of diarrhoea in eastern Indonesia was investigated in 74 children during the dry season in Ujung Pandang . Six of the children less than five years old with diarrhoea were infected with ETEC . One child was infected with tetracycline-resistant bacteria . The low prevalence of antibiotic resistance among ETEC in Indonesia is similar to that reported from Bangladesh, but very different from the situation in Thailand. Microbiol Immunol, 1983, 27(5), 425 - 31 Mechanism of antibiotic resistance in Mycobacterium intracellulare; Mizuguchi Y et al.; The mechanism of resistance of Mycobacterium intracellulare strain 103 and other clinical isolates to a variety of drugs including aminoglycoside and peptide antibiotics was investigated . Enzymatic inactivation of aminoglycoside and peptide antibiotics could not be demonstrated . Ribosomes of the strain were found to be sensitive to the antibiotics . The levels of resistance of strain 103 and other clinical isolates decreased dramatically when the culture medium was changed from Dubos agar to Tween 80-containing agar . These results suggest that a permeability barrier is the reason for naturally occurring resistance in M . intracellulare. Mol Gen Genet, 1983, 189(3), 516 - 8 Distribution of insertion element IS1 in natural isolates of Escherichia coli; Nyman K et al.; Total DNAs from twelve natural isolates of Escherichia coli from animals and humans were examined by hybridization with a probe for IS1 . Considerable variation in copy number was found . In the case of two strains isolated from the same individual, one strain contained no copies of IS1 and the other, much greater than 30 . Evidence was also obtained for the existence of IS1-like elements (iso-IS1s) of greater than 15% sequence divergence relative to the IS1 from antibiotic resistance plasmid R100. Mol Gen Genet, 1983, 190(3), 444 - 51 The finO gene of antibiotic resistance plasmid R100; Dempsey WB et al.; Lambda phages carrying the R100 finO gene have been isolated from an R100:: lambda cointegrate in which lambda was inserted into the R100 traD gene at kb coordinate 72.1 . Physical analyses of these phages place the finO gene within R100 SalI fragment D, near kb coordinate 82.0 . Analysis of proteins synthesized by the phages did not identify the finO gene product, although a constitutive protein of m.w . 30,100 was encoded by R100 DNA between kb coordinates 78.7 and 81.2. Gene, 1982 Nov, 20(1), 51 - 62 Physical analysis of antibiotic-resistance genes from Streptomyces and their use in vector construction; Thompson CJ et al.; Restriction endonuclease cleavage maps of five DNA fragments carrying genes for neomycin phosphotransferase and neomycin acetyltransferase (from Streptomyces fradiae), viomycin phosphotransferase (from S . vinaceus), and ribosomal methylases determining resistance to thiostrepton (from S . azureus) and MLS antibiotics (from S . erythreus) are described, together with a map for the SLP1.2 Streptomyces plasmid used to isolate the fragments . Construction of a versatile Streptomyces cloning vector (pIJ61) is reported . pIJ61 carries neomycin phosphotransferase and thiostrepton resistance genes and has unique BamHI and PstI sites which will allow clone recognition by insertional inactivation of neomycin resistance; cloning sites for several other endonucleases are also present . pIJ28, a shuttle vector for Streptomyces and E . coli, carries neomycin resistance and the SLP1.2 and pBR322 replicons. Southeast Asian J Trop Med Public Health, 1982 Sep, 13(3), 385 - 91 Seasonal variation of entertoxigenic Escherichia coli among children with diarrhoea in Bangkok; Maidin MA et al.; ETEC which produced both LT and ST or LT alone were isolated from 7.4 percent (18/244) of children with diarrhoea treated at two hospitals in Bangkok, Thailand between May 1, 1980 and April 30, 1981 . These enteric pathogens were only isolated from children with diarrhoea during the dry and the beginning of the wet season . Eighty-three percent (15/18) children infected with ETEC were infected with antibiotic resistant isolates . One hundred percent of LT + ST + E . coli and 76 percent (50/66) of LT + ST - E . coli were resistant to two or more antibiotics . Fourteen of 15 (93%) ETEC transferred antibiotic resistance and nine of 14 (64%) isolates which transferred resistance in bacterial conjugation experiments also transferred toxigenicity . This experience suggests that the widespread use of antibiotics in Thailand could increase the prevalence of antibiotic resistant enterotoxigenic bacteria. Zh Mikrobiol Epidemiol Immunobiol, 1982 Sep, (9), 45 - 9 {Genetic control of antibiotic resistance and the R plasmid properties of clinical E . coli strains}; Vakulenko SB et al.; The electrophoretic analysis of the plasmid DNA of multiresistant clinical E . coli strains revealed the presence of extrachromosomal DNA in 97% of the strains . The plasmid nature of resistance was established in 88-100% of E . coli strains resistant to chloramphenicol, ampicillin, streptomycin or kanamycin and in 67% of the strains resistant to tetracyclin . 24 out of 40 strains contained conjugative R-plasmids in which the determinants of resistance to kanamycin, ampicillin and chloramphenicol were transferred most frequently (82-93%), while the determinants of resistance to tetracyclin and streptomycin were transferred less frequently (45% and 35%, respectively) . Nonconjugative R-plasmids were detected in 15 out of 40 antibiotic-resistant strains; in these plasmids the determinants of resistance to streptomycin (65%) and tetracyclin (22%) were transferred most frequently. J Bacteriol, 1982 Aug, 151(2), 701 - 7 Plasmid loss and changes within the chromosomal DNA of Streptomyces reticuli; Schrempf H; The sporulating wild-type strain of Streptomyces reticuli, which produces a melanin pigment and the macrolide leucomycin, contains plasmid DNA of 48 to 49 megadaltons . Plasmidless variants had an altered secondary metabolism and a changed antibiotic resistance pattern . By using a new colony hybridization technique developed for streptomycetes, it could be shown that plasmidless variants could be transformed with the wild-type plasmid DNA, which, however, is quickly lost from regenerated mycelium . In contrast to the wild-type strain, the plasmidless variants contain amplified nucleotide sequences within the chromosomal DNA . The number and size of these sequences vary with the strain tested . Hybridization studies revealed that the reiterated sequences are neither amplified ribosomal nor plasmid genes, but are present in small concentrations within the wild-type chromosome . Some of them share extensive homologies with each other and are located at different positions within the chromosome . It is assumed that alterations in secondary metabolism are due to changes within both the chromosomal and the extrachromosomal DNAs of S . reticuli. J Bacteriol, 1982 Aug, 151(2), 678 - 85 Biochemical characterization of resistance determinants cloned from antibiotic-producing streptomycetes; Thompson CJ et al.; Determinants of antibiotic resistance have been cloned from four antibiotic-producing streptomycetes into Streptomyces lividans . Biochemical analyses of resistant clones revealed the presence of enzymes that had previously been characterized as likely resistance determinants in the producing organisms . These included: 23S rRNA methylases from S . azureus and S . erythreus, which confer resistance to thiostrepton and erythromycin, respectively; viomycin phosphotransferase from S . vinaceus; and aminoglycoside phosphotransferase and acetyltransferase from the neomycin producer S . fradiae . In general, the levels of antibiotic resistance of the clones were similar to those of the producing organisms . Although the two aminoglycoside-modifying enzymes from S . fradiae could independently confer only low-level resistance to neomycin, the presence of both enzymes in the same strain resulted in a level of resistance comparable with that of the producing organism. J Bacteriol, 1982 Aug, 151(2), 668 - 77 Cloning of antibiotic resistance and nutritional genes in streptomycetes; Thompson CJ et al.; Methodology which allows consistent shotgun cloning of streptomycete genes is presented . Parameters that increase transformation efficiency of Streptomyces lividans 66 were adjusted to generate reproducibly a population of cloned genes likely to represent the entire genome . Factors which influence the recovery of viable transformants include: growth phase of the mycelium, ionic and osmotic characteristics of the medium during protoplast formation and transformation, and moisture content and protoplast density during regeneration . A modified transformation procedure was devised which increased transformation frequency more than 20-fold (allowing up to 10(7) primary transformants per microgram of SLP1.2 covalently closed circular DNA) and greatly facilitated the cloning of drug resistance genes and biosynthetic genes, using one of two plasmid vectors . Viomycin resistance genes on BamHI or PstI fragments were cloned from S . vinaceus genomic DNA into S . lividans, using the SLP1.2 vector . At least three different S . vinaceus BamHI fragments (1.9, 5.8, or 8.5 kilobases) confer viomycin resistance; only one PstI fragment (4.3 kilobases) was found . Recombinant plasmids were all able to produce lethal zygosis and to be transferred by conjugation within S . lividans . SCP2 was used to clone S . coelicolor A3(2) genes that "complemented" the auxotrophic mutation hisD3, argA1, or guaA1 . Recombinant DNA technology can now be applied to economically and academically interesting problems unique to streptomycete molecular biology. Genetika, 1982 Jul, 18(7), 1067 - 74 {Genetic mapping of the mitochondrial markers of antibiotic resistance in PG-strain Saccharomyces cerevisiae yeasts}; Kal'dma IaA et al.; The mitochondrial mutations conferring resistance to antibiotics erythromycin, neomycin, oligomycin and mucidin, have been isolated in a number of strains . An attempt was made to genetically map these markers . The principle of coretention/or loss of two markers in UV induced petite mutants was used for localisation of the mitochondrial markers . The unique order of markers E-O-M-N was established in our experiments . The preferential loss of the Nr marker in petite mutants was observed . No significant differences in the gene order and in gene relative distances were observed between our PG strain and other nonrelated strains of Saccharomyces cerevisiae. Biochem Pharmacol, 1982 Jun 15, 31(12), 2161 - 7 Mitochondrial and nuclear mutagenicity of ellipticine and derivatives in the yeast Saccharomyces cerevisiae; Pinto M et al.; Haploid strains of the yeast Saccharomyces cerevisiae were tested for their sensitivity to ellipticine and nine derivatives; some of them exhibiting antitumor properties . Different mutagenic properties of ellipticines are described . Charged ellipticines, which were ineffective in Ames' bacterial assay, were found to be potent inducers of the mitochondrial p- mutation: induction proceeded even in the absence of growth . Uncharged ellipticines increased mitochondrial antibiotic resistance mutations, whereas charged derivatives decreased them . Ellipticine derivatives enhanced, reduced, or did not change the reversion frequencies of nuclear auxotrophic markers . The result depended on the strain being tested: no structure-effect relationship existed . As some ellipticine derivatives were mutagenic in Saccharomyces cerevisiae despite being ineffective in Ames' assay, multiple tests should be used to check that chemotherapeutic drugs are devoid of mutagenic properties. Southeast Asian J Trop Med Public Health, 1982 Jun, 13(2), 270 - 4 Antibiotic resistance and R plasmids in coliforms isolated from some Malaysian cooked foods; Khor SY et al.; Forty samples of Malaysian cooked foods were examined for the presence of antibiotic-resistant coliforms and R plasmids . Twenty seven (68%) of the foods had antibiotic-resistant coliforms and 5 (13%) had R plasmids . Nineteen samples (48%) had total bacterial counts over 10(6) per gm and in 5 samples, no coliforms were detected . Our findings show that cooked food may be one possible way by which R plasmids are spread . The control of the spread of R plasmids is discussed. Mol Biol (Mosk), 1982 May-Jun, 16(3), 575 - 80 {Cloning of the promoter of the RNA polymerase operon located before the structural gene of the beta-subunit}; Bass IA et al.; An EcoRI-fragment of the rpoBC operon carrying the end of the rplL gene, the intercistron region and the beginning of the rpoB gene cloned on the pBRH4 plasmid makes it tetracyclin-resistant, i . e . possesses the properties of a promoter . There is no appreciable difference in the degree of antibiotic resistance of recombinant plasmids carrying the main PJ promoter and the additional promoter. Am J Surg, 1982 Mar, 143(3), 343 - 8 Prospective, randomized, controlled trial of ticarcillin and cephalothin as prophylactic antibiotics for gastrointestinal operations; Brown JJ et al.; The effectiveness of ticarcillin (one 6 g dose at the start of the operation) and cephalothin (three 2 g doses given at 4 hour intervals from the start of the operation) as prophylactic antibiotics in operations on the colon, stomach, small bowel or obstructed biliary tract was determined in a prospective, randomized, blind study of 190 patients . Data from the 152 patients forming the definitive study revealed a significant reduction in the rate of wound and peritoneal infections with the use of ticarcillin (3.4 percent) and cephalothin (5.3 percent) over that with the use of a placebo (27.8 percent) . Cultures showed no evidence of antibiotic resistance in the contaminant organisms of patients who later developed infections . Both antibiotic regimens offered excellent protection against infection after gastrointestinal operations; neither produced untoward side effects . The very short duration of treatment, particularly with ticarcillin, conferred the additional benefits of low cost, simplicity of drug administration, and negligible risk of the emergence of resistant bacterial strains. C R Seances Acad Sci III, 1982 Feb 1, 294(5), 249 - 52 {Inhibition of the diffusion of plasmids by a nitrofuran derivative}; Michel-Briand Y et al.; Antibiotic resistance plasmids PR4, R6K, and RGN238 can transfer between Escherichia coli cells by conjugation (transfer frequency: 3 to 3.5 x 10(-4)) . Nifurzide, a nitrofuran derivative, greatly depresses plasmid transfer at concentrations (59 microM) which do not affect cell viability. Gene, 1982 Feb, 17(2), 189 - 96 A modified pBR322 vector with improved properties for the cloning, recovery, and sequencing of blunt-ended DNA fragments; Prentki P et al.; The construction of a plasmid vector which facilitates the cloning and recovery of blunt-ended DNA fragments is described . This plasmid, called pHP34, differs from pBR322 by a 10-bp insertion which introduces a unique SmaI site immediately flanked by two EcoRI sites . Blunt-ended DNA fragments cloned in the SmaI site can be recovered by digestion with EcoRI . Small cloned fragments can be chemically sequenced using a strategy which does not require their purification . The use of a plasmid related to pHP34 for in vitro mutagenesis by the insertion of a DNA linker fragment conferring an antibiotic resistance is also discussed. J Bacteriol, 1982 Feb, 149(2), 620 - 5 Transposon mutagenesis in Caulobacter crescentus; Ely B et al.; Transposons Tn5 (Km) and Tn7 (Tp and Sm) were transferred to Caulobacter crescentus via P-type antibiotic resistance factors . Transposition was demonstrated by the isolation of chromosomal insertions of each transposon . With C . crescentus strains harboring RP4 aphA::Tn7, the introduction of a wild-type RP4 resulted in the loss of the resident plasmid . Simultaneous selection for Kmr and Smr yielded colonies with chromosomal insertions of Tn7 . Examination of over 10,000 chromosomal insertions of Tn7 indicated no auxotrophic or motility mutants . Thus, Tn7 appears to have a high specificity of insertion in C . crescentus . The Mu-containing plasmid pJB4JI transferred Tn5 to C . crescentus, but the plasmid was not maintained . Control experiments showed that recovery of Mu-containing plasmids occurred at very low frequencies in C . crescentus and that the plasmids which were recovered had undergone extensive deletion of plasmid DNA . Presumably, some part of the Mu genome was not tolerated by C . crescentus . The instability of the Mu-containing plasmids makes them excellent vectors for the introduction of transposons, and we have used pJB4JI to isolated chromosomal insertions of Tn5 . When several thousand of these insertion mutants were examined, we found auxotrophic and motility mutants at frequencies of 1 and 2%, respectively . These results indicate that Tn5 had a low specificity of insertion in C . crescentus and therefore would be a useful mutagen for obtaining a variety of mutant phenotypes. Antibiotiki, 1982, 27(7), 511 - 6 {Multiple antibiotic resistance of actinomycetes from the nodules and rhizosphere of the alder}; Dobritsa SV; A total of 10 actinomycetous strains isolated from the root nitrogen-fixing tubercles and rhizosphere of alder were studied with respect to their sensitivity to 17 widely used antibiotics . By their cultural and morphological properties the isolates belonged to 3 groups . The strains were characterized by multiple resistance to the antibiotics . They were resistant to nalidixic acid, clindamycin and lincomycin and sensitive to novobiocin and vancomycin . Their behaviour with respect to the other antibiotics was diverse . The resistance spectra were specific of the strains belonging to groups I and II . The strains of group III were more heterogeneous by the character of their antibiotic sensitivity . The results of the study may be used for development of selective conditions for isolation of unusual actinomycetes from the alder tubercles and rhizosphere . The data on the diverse effect of some antibiotics on the growth and development of aerial mycelium of the strains belonging to group III may be used in the studies on cell differentiation of actinomycetes. Zh Mikrobiol Epidemiol Immunobiol, 1982, (11), 58 - 64 {Production of the mutant E strain of Rickettsia prowazekii by mutagen exposure}; Balaeva NM et al.; The possibility of obtaining the mutants of R . prowazekii, strain E, by exposing these organisms to the action of N-methyl-N-nitro-N-nitrosoguanidine was studied; this substance, used in doses of 5-10 micrograms, showed a mutagenic effect on rickettsiae suspended in physiological saline, after their exposure for 10-20 minutes at 37 degrees C . The mutants thus obtained proved to be resistant to erythromycin and rifampicin and were characterized by heterogeneity in the degree and stability of their antibiotic resistance . The effectiveness of selection was increased if mutagen-treated rickettsiae were selected after the first passage in chick embryos . The induced mutants differed from the original rickettsial strain by their lower infectiosity for chick embryos. J Mol Appl Genet, 1982, 1(4), 327 - 41 Transformation of mammalian cells to antibiotic resistance with a bacterial gene under control of the SV40 early region promoter; Southern PJ et al.; A bacterial gene (neo) conferring resistance to neomycin-kanamycin antibiotics has been inserted into SV40 hybrid plasmid vectors and introduced into cultured mammalian cells by DNA transfusion . Whereas normal cells are killed by the antibiotic G418, those that acquire and express neo continue to grow in the presence of G418 . In the course of the selection, neo DNA becomes associated with high molecular weight cellular DNA and is retained even when cells are grown in the absence of G418 for extended periods . Since neo provides a marker for dominant selections, cell transformation to G418 resistance is an efficient means for cotransformation of nonselected genes. Nucleic Acids Res, 1981 Dec 11, 9(23), 6265 - 78 Dissection of the r-determinant of the plasmid R100.1: the sequence at the extremities of Tn21; Zheng ZX et al.; We have sequenced the extremities of the transposon Tn21, isolated from the r-determinant of the multiple antibiotic resistance plasmid R100.1, and show that it is a member of the Tn3 family of elements. Biken J, 1981 Dec, 24(4), 127 - 35 Genetic labeling of an Ent plasmid that encodes heat-stable enterotoxin of enterotoxigenic Escherichia coli isolated from patients; Takeda T et al.; Ent plasmids of enterotoxigenic Escherichia coli that encode heat-stable enterotoxin (ST) and both ST and heat-labile enterotoxin (LT) were labeled with a kanamycin- and an ampicillin-resistance transposon, respectively . These transposons were kept stably in the respective Ent plasmids . By monitoring antibiotic resistance we could easily select strains carrying Ent plasmids . Strains carrying the labeled plasmids produced enterotoxins that were immunologically indistinguishable from those produced by the parent strains . Moreover the strain carrying a labeled ST-Ent plasmid produced 16 times more ST than the parent strain. Gene, 1981 Dec, 16(1-3), 227 - 35 Specific-purpose plasmid cloning vectors . I . Low copy number, temperature-sensitive, mobilization-defective pSC101-derived containment vectors; Hashimoto-Gotoh T et al.; Two cloning vector plasmids, pHSG415 (7100 bp) and a lambda phage cos site-containing derivative (cosmid) thereof, pHSG422 (8760 bp), were constructed from a low copy number plasmid (pSC101) replicon to permit the propagation of cloned DNA segments at low gene dosage levels . Two features of the vectors, namely temperature sensitivity of replication and inability to be mobilized by conjugative plasmids, cause them to exhibit a high level of "biological containment" . The essential characteristics of pHSG415 and pHSG422 may be summarized as follows: (1) their genome copy number is low (4--6 copies/chromosome); (2) their replication ceases at high temperature and they are rapidly lost from host cells grown at temperatures of 37 degrees C and above; (3) the relaxation nick site of pSC101, which is thought to be synonymous with its origin of transfer replication, is absent from the vectors; as a consequence, they are not mobilized to a significant extent by co-existing conjugative plasmids that are able to mobilize wild-type pSC101; (4) they contain unique insertion sites for DNA fragments generated by the following restriction endonucleases: EcoRI, XhoI, XmaI, HindIII and PstI; pHSG415 additionally contains single BamHI, BstEII and HincII sites and may also be used to clone PvuI-generated fragments; (5) the plasmids confer upon their host cells resistance to chloramphenicol, kanamycin and ampicillin, and every unique cloning site, except those of BamHI and BstEII, is located within one of these antibiotic-resistance genes. J Gen Microbiol, 1981 Nov, 127, pt 1, 155 - 60 Characterization of conjugative R plasmids belonging to the new incompatibility group IncU; Tschape H et al.; Five conjugative plasmids governing different antibiotic resistance patterns were identified in wild strains of enteric bacteria isolated in Czechoslovakia and the G.D.R . between 1976 and 1979 . They have been characterized as members of the new incompatibility group IncU (reference plasmid RA3 from Japan) . The molecular sizes of the IncU plasmids ranged between 18 and 37 megadaltons; their restriction fragment patterns indicated them to be distinct types. Science, 1981 Jul 31, 213(4507), 553 - 5 Plasmid DNA in Treponema pallidum (Nichols): potential for antibiotic resistance by syphilis bacteria; Norgard MV et al.; A plasmid DNA structure (approximate molecular weight = 7.5 X 10(6)) was identified in the human pathogen Treponema pallidum (Nichols) . The inability to isolate this plasmid from rabbit host tissue and the total lack of DNA homology of the plasmid with rabbit DNA has confirmed its Treponema pallidum origin . The observation documents a newly recognized and potentially significant genetic capability for Treponema pallidum. Ann Microbiol (Paris), 1981 Jul-Aug, 132B(1), 57 - 67 {"In vitro" study of attachment to human enterocytes in "Escherichia coli" strains isolated from infants with diarrheal disease (author's transl)}; Lafeuille B et al.; One hundred and four Escherichia coli strains isolated in the Hospital Centre of Clermont-Ferrand (France) from faeces of 26 infants with diarrheal diseases and of 29 infants with non-diarrheal diseases were tested for their ability to adhere to intestinal villi of the human small intestine . The haemagglutination (HA) type (with human, bovine, chicken and guinea-pig erythrocytes) and the agglutination of adhering strains by anti-colonization factor antigen I (CFA/I) serum and by anti-CFA/II serum were determined . Seventeen strains adhered to the brush border of the human small intestine . All these strains were isolated from infants with diarrhea; among these strains, only two possessed one CFA: one of them exhibited HA type I and was agglutinated by the anti-CFA/I serum; the second exhibited HA type II and was agglutinated by the anti-CFA/II serum . Six strains exhibiting HA type III and nine exhibiting other HA types were not agglutinated by anti-CFA/I or CFA/II sera . There were no relationship between the adherence and the serotypes or the antibiotic resistance of these strains. J Gen Microbiol, 1981 Jul, 125(Pt 1), 189 - 93 RNA polymerase binding sites on the broad host range plasmid RP4; Burkardt HJ et al.; Binding sites of Escherichia coli RNA polymerase on RP4 plasmid DNA were determined electron microscopically . Comparison of the RNA polymerase binding map and the genetic map of RP4 revealed several strong binding sites outside the well-known RP4 genes . RNA polymerase binding sites for the three antibiotic resistance genes were also detected . Two binding sites were observed for the tra-1 region, whereas the tra-2 and tra-3 regions showed no prominent affinity for RNA polymerase . The genomic regions for the replication origins, oriV (for vegetative replication) and oriT (for transfer replication, equivalent to rlx), both exhibited strong binding to RNA polymerase, as did genomic regions which code for trans-acting replication functions (trfA and trfB). Antimicrob Agents Chemother, 1981 Jun, 19(6), 1032 - 6 Drug resistance and R plasmids of Escherichia coli strains isolated from pigs, slaughterers, and breeders of pigs in Japan; Saida K et al.; We isolated 1,120 drug-resistant Escherichia coli strains from pigs, slaughterers, breeders of pigs, and urban residents and examined their drug resistance . With reference to resistance to tetracycline (Tc) chloramphenicol (Cm), streptomycin (Sm), and sulfanilamide (Su), Tcr, Smr, and Sur strains were most frequently isolated from pigs (57.9%), followed by slaughterers (50.2%) and breeders (42.4%) . By contrast, the isolation frequencies of Tcr, Smr, and Sur strains from urban residents were low (12.0%) . The isolation frequencies of R plasmids from resistant strains were more than 50% in the case of pigs, slaughterers, and breeders, whereas they were only 13.8% in urban residents . Kanamycin-resistant strains were frequently isolated from pigs (40.3%), slaughterers (22.6%), and breeders of pigs (25.4%), but seldom (only 3.4%) from urban residents . With ampicillin resistance, the frequencies of strains from pigs, slaughterers, breeders, and urban residents were 30.0, 21.5, 5.6, and 13.8%, respectively . R plasmids specifying these latter resistances were frequently seen from pigs (24.0%), slaughterers (23.6%), and breeders (21.1%), but they were not isolated from urban residents . The results suggest that the porcine gut can function as a reservoir of antibiotic resistance plasmids which can then be directly transferred to humans, with the highest frequency of such plasmids appearing in people in the most immediate contact with these animals. Gene, 1981 Jun-Jul, 14(1-2), 103 - 13 Physical characterization of mini-mu and mini-D108; Resibois A et al.; Several derivatives of phages Mu and D108 have been isolated that carry an internal deletion generated by one of the IS1 components of a Tn9 transposon located in the A, B, or S gene of the prenatal phage . The deletions remove most of the lytic functions of the phage but leave intact either genes A and B or gene A and the left and the right end of the phages . These deleted derivatives, called mini-Mu and mini-D108, were physically characterized by electron microscopy and digestion with restriction enzymes . Mini-Mu and mini-D108, which carry an antibiotic resistance marker, are described and some of their genetic properties are summarized in the paper by Toussaint et al . (1981). Nature, 1981 Apr 30, 290(5809), 794 - 7 Role of RNA transcripts in replication incompatibility and copy number control in antibiotic resistance plasmid derivatives; Rosen J et al.; The genes required for autonomous replication and incompatibility in the antibiotic resistance plasmids R100 and R1 have been located within a 2.5-kilobase region of the 90-kilobase genome, within which the incompatibility gene occupies a 1.3-kilobase region excluding the replication origin . We now report that three RNA species are synthesized in vitro from the 2.5-kilobase region, which R100 and R1 have in common . One, a long RNA molecule which is transcribed in the direction of DNA replication, probably acts as a messenger or a protein required for plasmid replication . The second RNA species, only 91 nucleotides long, is transcribed in the opposite direction, from a region of the DNA entirely contained within the first and known to specify incompatibility and copy control functions . The third RNA species, 150 bases long, is transcribed from a region including the replication origin; it may be a primer of DNA synthesis or, in conjunction with the second of the three RNA species, an influence in the control of replication. Nature, 1981 Apr 16, 290(5807), 607 - 8 Altered ribosomal RNA genes in mitochondria from mammalian cells with chloramphenicol resistance; Kearsey SE et al.; Chloramphenicol resistance in mammalian cells is cytoplasmically inherited . In yeast, a similar phenotype is caused by mutations in the mitochondrial DNA (mtDNA), and sequencing of carefully constructed strains has identified nucleotide monosubstitutions in the 3' region of the large (21S) rRNA gene which correlate with the antibiotic resistance . We have sequenced the corresponding section of mammalian mtDNA from chloramphenicol-resistant cell lines for comparison with the wild-type sequence . Differences between the sequences occur at positions similar to those altered in the yeast mutants, in a highly conserved region of the large (16S) rRNA gene. Vet Rec, 1981 Apr 11, 108(15), 325 - 8 A survey of antibiotic resistance of Escherichia Coli isolated from farm animals in Great Britain from 1971 to 1977; Jackson G; A total of 94,827 Escherichia coli strains isolated from cattle, sheep, pigs and poultry during the years 1971 to 1977 were tested for resistance to six antibiotics using a disc diffusion technique . The percentage of strains resistant to chloramphenicol (10 microgram), streptomycin (10 microgram), tetracycline (10 microgram), neomycin (10 Microgram) and furazolidone (15) were 16.8, 53.9, 42.7, 18 and 10.9 per cent, respectively; 52.2 per cent of strains (1971 and 1972) were resistant to 2 microgram ampicillin and 27.8 per cent of strains (1973 and 1977) were resistant to 10 microgram ampicillin . There was no evidence of an overall increase in antibiotic resistance during the seven year period . The animal species of origin was recorded for each of the 55,494 E coli strains examined during 1974 to 1977; 31,763 strains were isolated from cattle, 15,688 from pigs, 4582 from sheep and 3191 from poultry . Considerable variations in antibiotic resistance were recorded for strains isolated from different species. Poult Sci, 1981 Apr, 60(4), 738 - 43 Effect of oxytetracycline as a turkey feed additive; Swezey JL et al.; Turkeys were given oxytetracycline (OTC) as a feed supplement at levels of 0 g, 50 g, and 200 g OTC per ton of feed . After 8, 16, and 18 weeks the birds were sacrificed and bacteria were isolated from heart blood and liver tissue . When these isolates were tested for resistance against eight antibiotics, a direct correlation was observed between the level of supplement and the level of antibiotic resistance in the bacterial isolates . In postmortem studies on the livers from birds consuming both levels of OTC, an increase in the occurrence of lesions was observed . The livers from control birds appeared to have more granulomas. Ric Clin Lab, 1981 Apr-Jun, 11(2), 145 - 9 A multicentric study for serotyping and susceptibility to antibiotics of pneumococci in Italy; De Bac C et al.; A multicentric study of the incidence of pneumococcal serotypes was recently carried out in five different geographical areas in Italy . Two hundred and sixty-seven strains were typed using the quellung reaction with monospecific antisera, but only 28 of these were isolated directly from the site of infection . The most frequent serotypes were 19, 6, 3, 9, 4, 1 and 18 without remarkable differences regarding the area, age of patients and site of isolation . It was found that 60.3% of the serotypes isolated from all sources and 67.8% of those isolated from the sites of infection are contained in the currently used antipneumococcal vaccine . Antibiotic resistance was found versus aminoglycosides (34.9%), tetracycline (28.3%), chloramphenicol (5.2%) and penicillin (3.3%) . Cefoxitin appeared to be the antibiotic to which the pneumococci were most susceptible . Only two types, 19 and 16, resulted resistant to all the antibiotics. J Bacteriol, 1981 Apr, 146(1), 360 - 8 Cloning and expression in streptomyces lividans of antibiotic resistance genes derived from Escherichia coli; Schottel JL et al.; Hybrid plasmids that replicate in both Escherichia coli and Streptomyces lividans were constructed in vitro by joining the E . coli-derived plasmid pACYC184 or pACYC177, at their BamHI or PstI restriction site, respectively, to S . lividans plasmid pSLP111 . After introduction of the composite replicons into S . lividans by transformation, chloramphenicol (Cm) resistance encoded by pACYC184 and kanamycin resistance encoded by pACYC177 were phenotypically expressed in the S . lividans host . A Sau3A restriction endonuclease-generated deoxyribonucleic acid fragment from pACYC184 containing the entire structural gene for the Cm acetyltransferase enzyme, but lacking the nucleotide sequence ordinarily serving as the Cm resistance gene promoter, also specified resistance to Cm when introduced in either orientation into the BamHI or BclI endonuclease cleavage site of pSLP111 or into corresponding sites of the analogous plasmid pSLP101 . These findings make it unlikely that the biologically active CM acetyltransferase was being made in S . lividans as part of a fused protein, but instead indicate that the ATG start codon used for initiation of translation of the Cm resistance gene in E . coli was also utilized in S . lividans . In contrast, the synthesis of messenger ribonucleic acid that encodes the Cm acetyltransferase in S . lividans was, in at least one instance, apparently initiated at nucleotide sequences within the S . lividans plasmid vector, with resulting transcriptional read-through into the E . coli-derived deoxyribonucleic acid segment. Antibiotiki, 1981 Mar, 26(3), 109 - 12 {Effect of the conjugative plasmids of S . typhimurium antibiotic resistance on the growth indices of E . coli}; Lvanov NA et al.; The antibiotic resistance conjugative plasmids of Salm . typhimurium prolonged the lag-phase of coli bacteria . It was shown that the plasmids had a significant effect on the generation period either prolonging or shortening it . No correlation between the number of the antibiotic resistance determinants and resistance to separate antibiotics and the growth indices was found . The chromosome mutations of resistance to rifampicin and nalidixic acid in the strain of E . coli studied had no effect on duration of the lag-phase but resulted in shortening of the generation period. J Bacteriol, 1981 Feb, 145(2), 713 - 21 Formation of Escherichia coli Hfr strains by integrative suppression with the P group plasmid RP1; Martin RR et al.; Hfr strains of Escherichia coli were obtained by integrative suppression of a dnaA(Ts) mutation by the Inc P-1 plasmid RP1 without prior creation of an unnatural homology between the plasmid and the E . coli chromosome . Unmodified RP1 mobilized the polarized transfer of the chromosome in a counterclock-wise direction from a distinct origin between 81 min (pyrE) and 82 min (dnaA) with pyrE as a leading marker . Inheritance of RP1-Hfr chromosomal and antibiotic resistance genes was due to recombination with the recipient chromosome, as shown by the need for a functional recA system . The acquisition of temperature resistance and donor ability was accompanied by the disappearance of free plasmid when the selection pressure for integration was maintained (growth at 41 degrees C); the loss of temperature resistance and donor ability was accompanied by the reappearance of autonomous RP1 when the selection pressure was removed (growth at 30 degrees C). Nature, 1981 Jan 22, 289(5795), 326 - 8 Plasmid R1 DNA replication dependent on protein synthesis in cell-free extracts of E . coli; Diaz R et al.; Bacterial plasmids serve as model systems for studying the regulation of DNA replication . Elucidation of the molecular mechanisms involved in plasmid DNA synthesis requires the development of efficient cell-free plasmid replication systems . Such in vitro systems have previously only been described for Col E1-type plasmids and for the R6K plasmid . Here we report that extracts of Escherichia coli can carry out the complete replication of miniplasmids derived from the antibiotic-resistance plasmid R1 . This R1 replication system differs from the previously described ColE1 and R6K systems in its strict dependence on DNA-directed protein synthesis . We believe this to be the first report of the functional coupling of the three fundamental reactions of genetic information transfer (transcription, translation and replication) in a cell-free system. Arch Surg, 1981 Jan, 116(1), 53 - 7 Small-bowel perforations . A study of 32 cases; Nadkarni KM et al.; We studied 32 consecutive cases of small-bowel perforations treated in a single surgical unit during the last three years . Clinical features are typical and diagnosis is not difficult . Suprapubic peritoneal paracentesis in head-high position is the most accurate diagnostic investigation . Ultimate results are not related to cause, but are directly proportional to the degree of contamination of the peritoneal cavity, delay in manifestation, antibiotic resistance of the contaminating organism, and the method of treatment of the perforation . There were two deaths in the 16 patients who had exteriorization of the suture line (12.5%), compared with seven deaths in the group of 16 patients who did not have exteriorization (43.75%) . Exteriorization of the suture line (16 cases) is a superior method of treatment and significantly lowers the mortality. Mol Gen Genet, 1981, 184(1), 107 - 10 Physical characterization of the plasmid pON5300; Brana H et al.; The antibiotic resistance plasmid R1drd19Km- which has spontaneously lost its kanamycin resistance marker, and its derivative pON5300, were analysed using the restriction endonucleases SalI, BamHI, HindIII and EcoRI . The fragment patterns were compared with that of the R1drd19 and the fragments responsible for kanamycin resistance were found to be missing in R1drd19Km- and pON5300 . In these plasmids a 7 Mg/mol EcoRI fragment was observed instead of the D (6.3 Mg/mol) fragment of R1drd19 . Further a new 6 Mg/mol EcoRI restriction fragment was observed in pON5300 . Using double digestions it was shown that the new fragment does not carry restriction sites for HindIII, BamHI and SalI endonucleases . The non-homology of the analysed plasmid was proved electron microscopically by heteroduplex techniques . The possibility of amplification in the regulatory region for the expression of R-determinants in pON5300 is discussed. Cold Spring Harb Symp Quant Biol, 1981, 45 Pt 1, 107 - 13 Structural analysis of Tn5; Auerswald EA et al.; Nucleotide sequences have been determined for the 1.5-kb inverted repeats of Tn5 and for their junctions with the central unique region and with host DNA . The primary findings stemming from this analysis are: 1 . Integration of Tn5 is accompanied by the duplication of 9 bp of host DNA . 2 . Loss of Tn5 occurs by crossover between short, homologous nucleotide sequences near the junction between Tn5 and host DNA . 3 . The IR sequences contain long, open translational reading frames that may code for transposase proteins . 4 . The two IR sequences differ by a single-base change . This alteration accounts for the two functional differences observed between IRL and IRR: It shortens the reading frame for the transposase gene in IRL, and it improves the efficiency of a promoter for the nearby Km-resistance gene . 5 . The NH2 terminus of the structural gene for the Km-resistance gene maps at the very left border of the unique region, i.e., very close to the end of IRL . These results support the view that the inverted repeats of Tn5 stem from two identical copies of an originally independently moving DNA element . In the transposon, one of these, IRL, seems to have evolved toward a close physical and functional linkage with the antibiotic-resistance gene. J Biol Chem, 1980 Dec 10, 255(23), 11071 - 4 Activity in vitro of three replication origins of the antibiotic resistance plasmid RSF1040; Inuzuka N et al.; Replicating molecules of plasmid RSF1040, a deletion mutant of R6K, were synthesized in vitro and analyzed by electron microscopy . Initiation of replication occurs at three unique sites, ori alpha, ori beta, and ori gamma, within a 3900-base pair segment of the R6K genome . These sites are indistinguishable from the origins that are active in vivo . Frequencies of initiation at these three origins, however, are different from those observed in vivo . Replication proceeds unidirectionally in either direction from ori beta and ori gamma and in one direction from ori alpha . The replication terminus of the R6K genome is inactive in the in vitro system. Gene, 1980 Dec, 12(3-4), 235 - 41 Construction of plasmid vectors with unique PstI cloning sites in a signal sequence coding region; Talmadge K et al.; We have constructed a series of plasmids with unique PstI restriction sites within or near the pre-penicillinase signal sequence for protein secretion . To do this, we devised a rapid, simple method to eliminate undesirable unique restriction sites within plasmids while maintaining antibiotic resistance . We thus obtained a plasmid with a conveniently located, unique HincII site in the penicillinase gene of plasmid pBR322 which was used to generate, with BAL 31 exonuclease, deletions extending into the region encoding the signal sequence . DNA inserted into these plasmids can be translated in all three reading frames both including signal sequence, or starting immediately beyond it. J Bacteriol, 1980 Dec, 144(3), 1126 - 38 Plasmid replication functions: two distinct segments of plasmid R1, RepA and RepD, express incompatibility and are capable of autonomous replication; Danbara H et al.; The genetic determinants for replication and incompatibility of plasmid R1 were investigated by gene cloning methods, and three types of R1 miniplasmid derivatives were generated . The first, exemplified by plasmid pKT300, consisted of a single BglII endonuclease-generated deoxyribonucleic acid fragment derived from the R1 region that is located between the determinants for conjugal transfer and antibiotic resistance . Two types of miniplasmids could be formed from PstI endonuclease-generated fragments of pKT300 . One of these, which is equivalent to miniplasmids previously generated from plasmids R1-19 and R1-19B2, consisted of two adjacent PstI fragments that encode the RepA replication system of plasmid R1 . The other type contained a segment of R1, designated the RepD replication region, that is adjacent to the RepA region and that has not been identified previously as having the capacity for autonomous replication . Plasmid R1, therefore, contained two distinct deoxyribonucleic acid segments capable of autonomous replication . The RepA-RepD miniplasmid pKT300 had a copy number about eightfold higher than that of R1 and hence lacked a determinant for the regulation of plasmid copy number . Like R1, it was maintained stably in dividing bacteria . RepA miniplasmids had copy numbers which were two- to fourfold higher than that of R1 (i.e., which were lower than that of pKT300) and were maintained slightly less stably than those of pKT300 and R1 . The RepD miniplasmid was not maintained stably in dividing bacteria . Previous experiments have shown that incompatibility of IncFII group plasmids is specified by a plasmid copy control gene . Despite the fact that RepA miniplasmids of R1 were defective in copy control, they nevertheless expressed incompatibility . This suggests that two genes are responsible for plasmid copy control, one that specifies incompatibility and is located on RepA miniplasmids and another that is located outside of, but adjacent to, the RepA replication region . Hybrid plasmids composed of pBR322 and one PstI fragment from the RepA region, P-8, exhibited incompatibility towards R2 and RepA miniplasmids but not the RepD miniplasmid, whereas hybrids composed of pBR322 and the PstI fragment of the RepD region, P-3, exhibited incompatibility towards R1 and the RepD miniplasmid but not RepA miniplasmids . These results indicate that the two replication systems are functionally distinct and that, although the RepA system is the principal replication system of R1, the RepD system also plays a role in the maintenance of this plasmid. J Bacteriol, 1980 Nov, 144(2), 758 - 65 Naturally occurring plasmids exhibiting incompatibility with members of incompatibility groups I and P; Grant AJ et al.; From a group of naturally occurring antibiotic resistance plasmids, a number of plasmids were identified which were incompatible with members of incompatibility group P and also incompatibility group I alpha or I gamma . These plasmids also exhibited strong entry exclusion with members of group P only and showed a host range which resembled that of plasmids of group I rather than those of group P . Segregants of a number of these plasmids appeared to have lost some of the incompatability and/or surface exclusion functions . Studies of nucleic acid homology indicated that these plasmids were very similar to one another . They exhibited 15 to 20% nucleic acid homology with representatives of the I alpha and I gamma groups, yet showed less than 2% homology with the group P plasmid RP4. Am J Clin Pathol, 1980 Oct, 74(4 Suppl), 552 - 9 Regional quality assurance for the 1980's, current status and future directions; Lawson NS et al.; The current status of Regional Quality Control Programs has been summarized with respect to results of probes of data derived therefrom . Goals for the decade of the 1980's have been spelled out in the areas of program improvement and investigation of data . Primary areas for probing the data base are: analyte stability in quality control materials, state of the art in analytic precision and its relationship to analytical goals, accuracy assessment in regional programs, and utility of published criteria for establishment of antibiotic resistance or sensitivity by Kirby-Bauer technics. J Immunol, 1980 Oct, 125(4), 1494 - 8 Characterization of complement resistance in Escherichia coli conferred by the antibiotic resistance plasmid R100; Ogata RT et al.; We have examined the effect of the antibiotic resistance plasmid, R100, on the complement (C) mediated killing of Escherichia coli K-12 strains . The viabilities, in dilute normal rabbit serum (NRS), of 5 such strains were compared with the viabilities of the same strains harboring R100 . For 1 strain, J6-2, we also measured the effect of R100 on viability in normal human serum (NHS) and in guinea pig serum (GPS); in NRS, NHS,and GPS devoid of classical C pathway activity; and in NHS devoid of alternative pathway activity . Finally, we compared the depletion of individual complement components in sera exposed to J6-2 and J6-2 harboring R100 . Our results demonstrate that 1) R100 renders E . coli K-12 resistant to killing by NRS, NHS, and GPS; 2) the level of resistance, which ranges from 30- to 10,000-fold, is strain dependent and serum dependent; 3) R100 inhibits killing by both the classical and alternative C pathway . Resistance appears to involve a disruption on the C pathway subsequent to the activation of C5. J Clin Microbiol, 1980 Aug, 12(2), 264 - 70 Antibiotic resistance in Enterotoxigenic and non-enterotoxigenic Escherichia coli; DeBoy JM 2nd et al.; Antibiotic disk susceptibility tests were done on 220 strains of Escherichia coli belonging to serotypes reported in the literature to be associated with the production of enterotoxin . A total of 128 (58%) were resistant to one or more antibiotics, sulfa drugs, or chemotherapeutic agents . An analysis of these strains revealed primary, secondary, and tertiary drug resistance patterns that indicated a selective pattern in the formation of multiple drug resistance in E . coli . Resistances to certain antibiotics were more likely to occur in pairs and triads (secondary resistance patterns) that were often combined or coexisted in a single strain of E . coli to produce tertiary drug resistance patterns, conferring drug resistance to five or six different antibiotics . Among enterotoxin-associated serotypes, single and multiple drug resistance was less frequently associated with enterotoxin-produced strains than with strains from the same serotype that were not enterotoxigenic . Within the enterotoxigenic E . coli, single and multiple resistance to antibiotics was more frequent in strains producing only heat-stable enterotoxin (ST) than in strains producing only heat-labile enterotoxin (LT) or both . The number of resistances to different antibiotics per resistant strain averaged approximately 1.4 for LT plus ST or LT strains, and 3.9 for ST strains and nonenterotoxigenic strains . Phenotypic characterization of 170 strains for four usually plasmid-mediated characteristics showed that the number of antibiotics to which a strain was directly resistant varied with the type and number of plasmid-mediated characteristics present. J Infect Dis, 1980 Aug, 142(2), 273 - 8 Enterotoxigenic Escherichia coli carrying plasmids coding for antibiotic resistance and enterotoxin production; Echeverria P et al.; Nine strains of enterotoxigenic Escherichia coli that were resistant to antibiotics were tested for their ability to transfer both antibiotic resistance and enterotoxigenicity to E . coli K12 . All nine isolates transferred antibiotic resistance in bacterial conjugation experiments, and in seven of these matings enterotoxigenicity was also transferred . To determine whether the genetic information coding for the production of enterotoxin and antibiotic resistance was located on the same plasmid in these strains, phage P1 transduction experiments were performed . P1 lysates prepared from enterotoxigenic antibiotic-resistant transconjugants were tested for their ability to transduce both phenotypes . Only P1 lysates prepared from transconjugants of E . coli 719B5 (O18ab:H27) were found to transduce resistance to streptomycin, sulfisoxazole, and tetracycline, as well as the ability to produce heat-labile and heat-stable enterotoxin . The results of these experiments strongly suggest that the genetic data coding for antibiotic resistance and enterotoxin production in E . coli 719B5 are carried on the same plasmid replicon. Aust J Exp Biol Med Sci, 1980 Aug, 58(4), 331 - 8 Endonuclease fingerprinting of plasmids mediating gentamicin resistance in an outbreak of hospital infections; Davey RB et al.; Three plasmids which each determined the same extensive antibiotic resistance phenotype, including resistance to gentamicin, and which had been recovered from organisms involved in an outbreak of gentamicin-resistant infections in Melbourne hospitals in 1975--1976, were analysed by fingerprinting with the restriction endonucleases Eco RI, Hind III and Pst I, In each case the fingerprints for all three plasmids were identical, despite the fact that each plasmid originated in a different host species at different hospitals . This observation confirms our earlier hypothesis (Davey and Pittard, 1977) that the plasmids mediating gentamicin resistance in the outbreak were the closely related descendants of one ancestral (IncL) plasmid. Nature, 1980 Jul 31, 286(5772), 525 - 7 DNA cloning in Streptomyces: resistance genes from antibiotic-producing species; Thompson CJ et al.; The biochemical and morphological differentiation of actinomycetes makes them academically and economically interesting . Their secondary metabolites provide the majority of medically and agriculturally important antibiotics (streptomycete genes may also be the primary source of clinically important antibiotic resistance); their complex morphological developmental cycle involves a series of changes from vegetative mycelial growth to spore formation . Recombinant DNA technology would add a powerful new dimension to the analysis of these various aspects of actinomycete biology and would also facilitate the development of industrial strains with increased antibiotic yield, or capable of making new antibiotics . For most of these purposes, cloning of genes within and between actinomycetes is required to study the expression of particular genes in genetic backgrounds defined by mutations of the characters under study . To achieve this, we have now developed a method for molecular cloning involving the transfer of genes between unrelated streptomycetes. Antibiotiki, 1980 Jun, 25(6), 433 - 7 {Identification and characteristics of the conjugative R plasmids of conditionally pathogenic E . coli isolated from chronic pyelonephritis patients}; Pekhov AP et al.; The study on 63 strains of conditionally pathogenic E . coli isolated from patients with chronic pyelonephritis showed that the bacteria of the 47 strains (74.6%) were resistant to one or several antibiotics . 7 strains of such bacteria carried R-plasmids capable of transferring into the cells of E . coli K-12 during conjugation . Most of the identified 9 R-plasmids belonged to the class of the F-like plasmids and were characterized by similar lots of antibiotic resistance markers . DNA of the detected R-plasmids were treated with endonuclease (restrictase) EcoRI . After that the fragments were analysed by means of electrophoresis in agarose gel . On the basis of the restrictogrames it was concluded that the plasmids studied were not identical . A possibility of detecting complexes consisting of different plasmids carrying similar lots of antibiotic resistance markers in the cells of the same strain was shown. Proc Natl Acad Sci U S A, 1980 Jun, 77(6), 3567 - 70 Transformation of mammalian cells with an amplifiable dominant-acting gene; Wigler M et al.; We have transferred a mutant hamster gene coding for an altered dihydrofolate reductase to wild-type cultured mouse cells by using total genomic DNA from methotrexate-resistant Chinese hamster ovary A29 cells as donor . By demonstrating the presence of hamster gene sequences in transformants we have provided direct evidence for gene transfer . Transformants selected for increased resistance to methotrexate contain increased amounts of the newly transferred gene . We have used this mutant dhfr gene to introduce the Escherichia coli antibiotic resistance plasmid pBR322 into animal cells . Amplification of the dhfr sequences results in amplification of the pBR322 sequences as well . The use of this gene may allow the introduction and amplification of virtually any genetic element in various new cellular environments. Zentralbl Bakteriol A, 1980 Jun, 247(1), 25 - 34 Infectious drug resistance in E . coli isolated from livestock; Adetosoye AI; Escherichia coli strains isolated from clinically healthy and sick animals in Lagos and Oyo States of Nigeria were tested for drug resistance and distribution of R-factors . Fifteen multiple and 3 single (OT, S, S3) antibiotic resistance patterns were obtained among 333 isolates . Of the 285 resistant strains, 133 transfered their resistant determinant to sensitive E . coli K 12 recipients in part or as a block . None of the donors had sex pili and they were not lysed by Ms2 phage . It required about 2 h for E . coli K 12 to acquire a resistance determinant from E . coli strains Nos . 295, 62 and 67 habouring resistance to oxytetracycline, streptomycin and compound of sulphonamides (S3) . The number of recipient cells that formed transconjugants increased with the time of incubation. Gene, 1980 May, 9(3-4), 175 - 93 Construction and characterization of E . coli promoter-probe plasmid vectors . II . RNA polymerase binding studies on antibiotic-resistance promoters; West RW Jr et al.; The binding of Escherichia coli RNA polymerase to antibiotic-resistance promoters was examined using the nitrocellulose filter assay . Four filter-retainable HaeIII fragments were observed with pBR322 and the promoter-probe plasmids, pBRH1, pBRH2 and pBRH4 . Of the three fragments studied, two were shown to carry promoters for the ampicillin (Ap) and tetracycline (Tc) resistance genes, while the third present in pBRH1 appears to be the promoter for colicin E1 immunity (Colimm) . Although the formation of filter-retainable complexes involving the Tcr promoter was sensitive to high salt, Apr promoter complexes were not . It was also shown that plasmids containing only the "firm-binding" portion of the Tcr promoter could still bind RNA polymerase in vitro despite the fact that these plasmids confer no in vivo Tcr . Additional filter-binding experiments performed with AluI-digested pBR322 DNA revealed the presence of a fifth RNA polymerase binding site on pBR322 . This site is probably the promoter for the 100 bp transcript thought to be involved in the initiation of plasmid replication . An analysis of the recombinant plasmid (pKTR25) which carries the Kan-B portion of the EcoRI kanamycin (Kn) resistance fragment revealed that this fragment contains two RNA polymerase binding sites . We believe that these sites are responsible for the insertional activation of the Tcr gene and may be the promoters for the Knr and fusidic acid (Fa) resistance genes. J Bacteriol, 1980 Mar, 141(3), 1015 - 23 Physical characterization of plasmids determining synthesis of a microcin which inhibits methionine synthesis in Escherichia coli; Perez-Diaz JC et al.; Plasmid deoxyribonucleic acid (DNA) isolated from each of three antibiotic-resistant clinical strains of Escherichia coli producing the same microcin showed multiple bands upon agarose gel electrophoresis . Transformants selected either for microcin resistance or ampicillin resistance yielded plasmid DNA corresponding in size to only one of the multiple bands . Plasmids, isolated from all three hosts, which determined microcin resistance and microcin production measured about 4 megadaltons by sucrose density, restriction enzyme, and contour length analyses; cleavage of the DNAs by each of eight restriction enzymes showed the same response, and DNA-DNA hybridization indicated complete homology . The antibiotic resistance plasmids of the three host strains were uniformly larger, were of different sizes, and showed different restriction enzyme cleavage patterns . One of these R plasmids (pCP106) also determined the synthesis of the same microcin, and DNA-DNA hybridization studies indicated an approximate 2.4-megadalton homology with the 4-megadalton microcin plasmid pCP101 . The microcin plasmids were present at approximately 20 copies per genome equivalent and were nonconjugative, whereas the R plasmids had a copy number of about 1, were conjugative, and could mobilize the microcin plasmid . Microcin plasmid pCP101 showed replication properties similar to those of a number of small multicopy plasmids such as ColE1. Genetics, 1980 Feb, 94(2), 425 - 43 The population biology of bacterial plasmids: a priori conditions for the existence of mobilizable nonconjugative factors; Levin BR et al.; A mathematical model for the population dynamics of nonconjugative plasmids that can be mobilized by conjugative factors is presented . In the analysis of the properties of this model, primary consideration is given to the conditions under which these nonself-transmissible extrachromosomal elements could become established and would be maintained in bacterial populations . The results of this analysis demonstrate the existence of conditions where, as a consequence of infectious transmission via mobilization, nonconjugative plasmids could become established and be maintained even when the bacteria carrying them have lower reproductive fitnesses than plasmid-free members of the population . However, these existence conditions are stringent and suggest therefore, that it is highly unlikely that plasmids of this type would become established and maintained without some direct selection favoring their carriage . The general implications of these results and limitations of the model are discussed . Brief consideration is also given to the implications of these theoretical findings to the problems of the spread of multiple antibiotic resistance plasmids (R-factors) and the risk of contaminating natural populations of bacteria with chimeric plasmids produced by work with recombinant DNA. Mol Gen Genet, 1980 Feb, 177(3), 413 - 9 Site-specific deletion at the replication origin of the antibiotic resistance factor R1; Kollek R et al.; The recombinant plasmid pRK101 carrying the complete replication origin of the antibiotic resistance factor R1 suffers frequently a deletion of 218 base pairs, removing parts or all of the origin sequence . This deletion seems to occur always when the Pst-E fragment carrying the replication origin is inserted into the cloning vector pBR322 in an orientation where the direction of R1 replication is the same as that of the vector plasmid and frequently when it is inserted in the opposite direction . DNA sequence analysis around the junction site generated by the deletion in three independently isolated deletion mutants reveals that the deletion occurs at a specific site, namely the end of a 22 bp sequence which is repeated almost identically at the other end of a segment of 197 bp . During the deletion one repeat unit is removed whereas the other is retained . The DNA sequence included by the two repeats contains high symmetric structures, i.e . inverted repeats, direct repeats and palindromes which may represent regulatory sites of the origin. Genetika, 1980, 16(9), 1556 - 63 {Mitochondria antibiotic-resistance mutations in Saccharomyces cerevisiae, their recombination and effect on induction of respiration-deficient mitochondrial mutations by ethyl alcohol}; Bandas EL et al.; The locus of neomycin resistance is located at near equal distances from the loci of erythromycin and oligomycin resistance on mitDNA, as the analysis of recombination frequencies between three markers has shown in yeast Saccharomyces cerevisiae descending from XII race . We studied the influence of the resistance to these antibiotics on the yield of spontaneous and induced by 24% ethanol rho- mutations in 2 haploid and 126 diploid strains of yeast . All of the neomycin resistant strains were characterized by significantly lower level of spontaneous mutations in comparison with other strains . Ethanol did not induce rho- mutagenesis in neomycin resistant strains or slightly increased it (up to 2-4%) . However ethanol increased the yield of these mutations up to 58% in neomycin sensitive strain . The killing effect of ethanol on diploid strains did not depend on their genotype. Can J Comp Med, 1980 Jan, 44(1), 101 - 8 Influence of oral antibiotics on resistance and enterotoxigenicity of Escherichia coli; Bourque R et al.; Three groups of five piglets were formed and 1390 Escherichia coli isolates were obtained during the 45-day period of observation . One of the groups received feed without antibiotic whereas the second received feed containing 100 ppm neomycin and the third feed with 100 ppm neomycin plus 100 ppm tetracycline . Rectal swabbings for bacterial isolation were repeated ten times, twice during an adaptation period and eight times during the treatment period . Resistance among the isolates to tetracycline, streptomycin and triple sulfas remained high throughout this experiment whereas resistance to neomycin, chloramphenicol and ampicillin were found to increase significantly under the influence of antibiotic supplemented feed . This increase of antibiotic resistance was associated with an increase of the percentage of isolates harboring an R . factor . When comparing the ability of strains harboring an R factor to receive the plasmid Ent from the E . coli K12 (P155) with isolates not harboring such a plasmid, no significant difference was observed in their ability to receive the Ent plasmid. Mol Gen Genet, 1980 Jan, 177(2), 355 - 8 The use of mitochondrial mutants in the isolation of hybrids involving industrial yeast strains; Spencer JF et al.; Methods for the isolation of hybrids in which one or both of the parental strains are industrial yeasts, using mitochondrial mutations as markers for the selection and isolation of the hybrids, are described . The systems used included crosses of industrial strains with auxotrophic laboratory strains which also carried a mitochondrial antibiotic resistance mutation, crosses using an auxotrophic laboratory strain and a petite mutant of an industrial strain carrying a rescuable antibiotic resistance mutation, and crosses using a petite mutant of an industrial strain, carrying a rescuable mitochondrial mutation for antibiotic resistance and a respiratory-competent industrial strain which carried some other marker. J Bacteriol, 1980 Jan, 141(1), 213 - 22 Regions of broad-host-range plasmid RK2 which are essential for replication and maintenance; Thomas CM et al.; The sites of cleavage on the map of the broad-host-range plasmid RK2 (56 kilobases) were determined for the BglII, PstI, and SmaI restriction enzymes, and the determinants for tetracycline and ampicillin resistance were localized . The cleavage sites were clustered at or near the drug resistance genes . To localize regions required for plasmid replication and maintenance in Escherichia coli, we deleted nonessential regions of RK2 by partial digestion with the restriction endonuclease HaeII to produce small derivatives . The smallest stable replicon obtained contained five HaeII fragments of RK2 which total 5.4 kilobases . These fragments were derived from three regions of RK2 that are separated from each other by antibiotic resistance genes . One of these HaeII fragments (0.75 kilobases) has the properties expected of the origin of replication . The outer four fragments, located in two separate regions of RK2, were found to provide, in trans, functions that permit the replication of the HaeII fragment carrying the origin of the replication . These results indicate that at least two plasmid-encoded genes, capable of acting in trans, and a replication origin are required for RK2 replication and maintenance. Arzneimittelforschung, 1980, 30(3a), 529 - 33 {Antibiotic resistance factors and "jumping" genes (author's transl)}; Saedler H; Antibiotics are natural products inhibiting the growth of bacteria . In research they play an important role in studying the details of bacterial macromolecular synthesis . However, their major importance lies in application, i.e., in treatment of infectious bacterial diseases and as additives to livestock feed . The application of antibiotics, however, presents serious problems: the development and spread of antibiotic-resistant bacterial strains which impede therapy. Genetics, 1979 Dec, 93(4), 797 - 831 Absence of detectable mitochondrial recombination in Paramecium; Adoutte A et al.; An extensive search for recombination between mitochondrial markers was carried out in Paramecium tetraurelia . Thirty-two combinations, altogether involving 24 different markers, were studied . The markers belonged to the three main categories of mitochondrial mutations presently available in this organism, (a) Spontaneous or UV-induced antibiotic resistance mutations, most probably affecting mitochondrial ribosomes, (b) nitrosoguanidine-induced antibiotic resistance markers displaying thermosensitivity or slow growth, enabling easy selection of possible wild-type recombinants, and (c) mitochondrial partial suppressors of a nuclear gene, probably corresponding to molecular alterations distinct from the preceding two categories . In addition, different genetic configurations were analyzed (i.e., mutant X mutant, double-mutant X wild-type, etc.).--None of the combinations yielded any evidence for the occurrence of recombined genomes despite the fact that: (1) all of them were studied on a large scale involving the screening of at least several thousand mitochondrial genomes (often several millions), (2) in many of them the detection level was sufficiently high to enable the isolation of spontaneous mutants in control cells, and (3) in several of them, reconstitution experiments carried out in parallel show that the conditions were fully adequate to detect recombinant genotypes . The results are in marked contrast with those obtained on the few other organisms in which mitochondrial recombination has been studied, particularly Saccharomyces cerevisiae, in which mitochondrial recombination is intense.--The most likely basis for the various manifestations of mitochondrial genetic autonomy in Paramecium, described in this as well as in previous publications, is that the chondriome of this organism is made up of thousands of structurally discrete, noninteracting units. Biochemistry, 1979 Nov 13, 18(23), 5128 - 34 Modification of deoxyribonucleic acid by a diol epoxide of benzo{a}pyrene . Relation to deoxyribonucleic acid structure and conformation and effects on transfectional activity; Pulkrabek P et al.; The effects of secondary structure on DNA modification by (+/-)-7 beta, 9 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzol{a}pyrene {(+/-)BPDE I} were investigated . No differences in the total extent of (+/-) BPDE I binding to double- and single-stranded calf thymus DNA were found . High-performance liquid chromatography (LC) of the nucleoside adducts obtained from hydrolysates of native and denatured calf thymus, as well as from superhelical and linear plasmid DNA, indicated that in all cases the major adduct (60--80% of total adducts) was formed by reaction of the (+) enantiomer of BPDE I with the N-2 position of dG residues in the DNA . A minor adduct formed from the reaction of the (-) enantiomer with dG residues was also detected and was present in greater amounts in denautred DNA than in native DNA . Small amounts of BPDE I--dA and BPDE I--dC adducts were also detected in both the single- and double-stranded DNAs . Restriction enzyme analysis of BPDE I modified SV40 and phage lambda DNA provided evidence that the modification of DNA by this carcinogen is fairly random with respect to nucleotide sequence . Partial hydrolysis of modified plasmid DNA by the single-strand-specific S1 nuclease and LC analysis of the nucleoside adducts in the digested and undigested fractions of the DNA revealed no preferential excision by the S1 nuclease of the different BPDE I--deoxynucleoside adducts . Functional changes in BPDE I modified DNA were demonstrated . With increasing extents of modification, there was a decrease in the ability of plasmid DNA to transfect a receptive Escherichia coli strain to antibiotic resistance. Can J Microbiol, 1979 Nov, 25(11), 1264 - 9 Selective infection of maize roots by streptomycin-resistant Azospirillum lipoferum and other bacteria; Dobereiner J et al.; The percentage of low-level streptomycin-resistant (20 microgram/mL) bacteria in surface-sterilized or washed maize roots was more than a thousand times higher than that in soil populations . There was also a higher incidence of resistant bacteria in rhizosphere as compared with non-rhizosphere soil and bacteria isolated from maize roots were relatively tolerant to several other antibiotics . Azospirillum lipoferum was predominant in surface-sterilized roots of field-grown maize and was low-level streptomycin-resistant while most soil isolates were sensitive . Inoculation with A . brasilense isolated from wheat roots was unsuccessful in terms of establishment even when streptomycin-resistant strains were used . Unidentified causes of specific plant-bacteria affinities therefore transcend the role of antibiotic resistance in maize root infection. J Bacteriol, 1979 Nov, 140(2), 400 - 7 Plasmid vehicles for direct cloning of Escherichia coli promoters; An G et al.; A multicopy plasmid cloning vehicle, pGA22, which carries genes for ampicillin resistance (Apr), tetracycline resistance (Tcr), chloramphenicol resistance (Cmr), and kanamycin resistance (Kmr) has been constructed . This plasmid has five unique sites for restriction endonucleases EcoRI, PstI, XhoI, SmaI, and SalI within antibiotic resistance genes . pGA22, which is 5.1 megadaltons in size, has a low copy number (probably fewer than 10 per genome), is capable of relaxed replication, and is mobilized by F-factor at a frequency of 10(-5) . A series of promoter-cloning vehicles, pGA24, pGA39, and pGA46, has been developed from pGA22 . In these plasmids the natural promoter for Tcr has been removed and has been replaced by small deoxyribonucleic acid fragments carrying unique sites for several restriction endonucleases . Cells carrying these vectors are sensitive to tetracycline unless insertional activation of the Tcr occurs by cloning a promoter-carrying deoxyribonucleic acid fragment in one of the unique sites adjacent to the 5' end of Tcr . In this way, promoters carried on a HindIII-generated deoxyribonucleic acid fragment can be inserted at the HindIII site of plasmid pGA24, pGA39, or pGA46 . A promoter in fragments generated by digestion with restriction endonuclease XmaI or PstI or by any restriction endonucleases which generate flush ends, such as SmaI, PvuII, HpaI, HincII, or HaeIII, can be clones in plasmid pGA39 . Plasmid pGA46 can be used to detect a promoter fragment carried on a BglII, BamHI, MboI, or PstI fragment . We also describe a plasmid, pGA44, with a unique KpnI site in the rifampin resistance gene rpoB. Mol Gen Genet, 1979 Nov, 176(3), 319 - 34 Lambda transducing phages derived from a FinO- R100::lambda cointegrate plasmid: proteins encoded by the R100 replication/incompatibility region and the antibiotic resistance determinant; Dempsey WB et al.; Three lambda transducing phages have been isolated from pEDR20, an R100::lambda cointegrate plasmid in which the lambda insertion inactivated the R100 finO gene . Physical analysis of the three phages showed that the lambda is inserted at kilobase coordinate 81.3 of R100 . All three phages carry different amounts of R100 DNA in the left arm of lambda . Each pahge contains ISlb, the mer genes and the region between coordinate 81.3 and 88.6; thus, all contain the genes necessary for R100 replication . One phage, VA lambda 73, contains the entire r-determination of R100 in addition to the above DNA . Five proteins coded by the region between 81.3 and 88.6 were detected . These had subunit molecular weights of 10,400; 12,200; 16,200; 19,600; and 38,300 . The first was made constitutively and the other four only from a lambda promoter . Other constitutive proteins were one from the cml fus region with a molecular weight of 22,400 (cml) and two from the str sul region with molecular weights of 31,500 (str?) and 30,100 (sul?) . Mercuric ion induced synthesis of at least 10 proteins . Six of these were known from earlier work . The total size of the proteins which appear to derive from the mer genes exceeds by a factor of 1.5, the coding capacity of this region without overlapping genes . Some, or all of these extra proteins may be chromosomal in origin, possibly derepressed in response to mercury gene products. J Antibiot (Tokyo), 1979 Jul, 32(7), 746 - 52 Selecting interspecific human-mouse and Chinese hamster-mouse hybrids using a new half-selection technique with a polyene antibiotic; Fisher PB et al.; Interspecific human-mouse and Chinese hamster-mouse hybrids were isolated from polyethylene glycol fused cells by a new half-selection technique employing a structurally modified polyene macrolide antibiotic, amphotericin B methyl ester (AME), and HAT media . Unfused parental cells were killed as a result of innate sensitivity to AME or their genetic deficiency, absence of thymidine kinase (TK-) or hypoxanthine guanine-phosphoribosyl transferase (HGPRT-) . In contrast, hybrid colonies were isolated after two to three weeks growth in three or four changes of HAT-AME media and subsequent growth in HAT media alone . The ability of hybrid cells to proliferate using this selective protocol indicates that genetic complementation resulted, and polyene antibiotic resistance was expressed as a dominant phenotypic property in the hybrids . Hybrid selection was dependent on: (1) the number of cells of each parental cell type co-cultivated; (2) the level of polyene antibiotic administered; and (3) the time interval before selection was initiated . The half-selection technique described in this report is simple to use, very effective in eliminating unfused parental cells and increases the potential types of hybrids which can be formed . Only one parental cell type need contain a biochemical defect, whereas the second parental type can be genetically normal. Rev Epidemiol Sante Publique, 1979 Apr 26, 26(6), 469 - 77 {Comparison of various characters and antigenic structure in S . aureus strains cultivated in hospitalized patients and in healthy carriers}; Chomarat M et al.; A comparison has been done between various characters of 170 non epidemic strains cultivated from hospitalized patients and 29 strains originated from healthy carriers without any hospital contact and antibiotic treatment since 6 months . Following characters have been tested: M.I.C . of 13 antibiotics, heterogenous methicillin resistance, enzymatic antibiotic resistance, macrolide inducible or constitutive type resistance, mercuric chloride susceptibility; phage types; enzymes and toxins production . Antigenic structure has been studied, in particular production of protein A, A beta teichoc acid and type antigens . Significant differences have been observed between hospital and healthy carriers strains; these later strains are antibiotic susceptible, produce few toxins and enzymes, are not frequently phage typable . Their antigenic structure shows also significant differences: A beta-teichoic acid is less frequently detected; type antigens are less frequent and different . Role of these surface antigens in virulence is discussed. Mol Gen Genet, 1979 Mar 27, 171(3), 277 - 85 The nucleotide sequence of a DNA fragment from the replication origin of the antibiotic resistance factor R1drd19; Oertel W et al.; The recombinant plasmid pRK101 contains a DNA fragment which carries the complete replication origin of the antibiotic resistance factor R1drd-19 inserted into the vector plasmid pBR322 . In a spontaneously arising mutant of this plasmid (pRK103) a deletion of about 215 base pairs (bp) has been detected by heteroduplex analysis and mapping with restriction endonucleases . Essential parts of the replication origin must be located in the deleted sequence . The deletion mutant pRK103, in contrast to its parent plasmid pRK101 is not replicated under the control of the R1 replicon, even when the R1 factor or copy mutants of it are present within the same cell . These latter plasmids can complement a plasmid-specific protein not coded by pRK101 but essential for R1-directed replication . The nucleotide sequence of a 252 bp HpaII fragment covering about 170--200 bp of the deletion was determined . This piece of DNA is rich in G and C and contains a series of small palindromes, symmetrically arranged repeated sequences and short selfcomplementary structures which may be of significance for the initiation of the DNA replication . The possiblity that the sequenced DNA fragment comprises a major part of the replication origin of R1drd-19 is discussed. Proc Natl Acad Sci U S A, 1979 Mar, 76(3), 1150 - 4 Nucleotide sequence of the region of an origin of replication of the antibiotic resistance plasmid R6K; Stalker DM et al.; A 2.1-kilobase segment of the antibiotic resistance plasmid R6K carries sufficient information to replicate as a plasmid in Escherichia coli . This segment contains a functional origin of replication and a structural gene for a protein, designated pi, that is required for the initiation of R6K replication . The nucleotide sequence of a 520-base-pair portion of this 2.1-kilobase segment that includes the functional origin of replication and the region adjacent to the start of the pi structural gene was determined . A striking feature of the sequence is the presence of seven 22-base-pair direct repeats joined in tandem in the region adjacent to the start of the pi gene . A possible role of the tandem repeats in the regulation of expression of the pi protein and the control of initiation of replication of the plasmid R6K is discussed. J Bacteriol, 1979 Feb, 137(2), 977 - 89 Transposition of a duplicate antibiotic resistance gene and generation of deletions in plasmid R6K; Holmans PL et al.; Transformation experiments showed that spontaneous deletions which result in loss of streptomycin resistance and an increase in conjugal transfer efficiency are present at a frequency of about 10(-4) in plasmid molecules of R6K . Similar deletions were thus readily selected by conjugal transfer of R6K, and their appearance was dependent upon recA+ activity in either donor or recipient host . The deoxyribonucleic acid segment deleted in four mutants examined was concluded to extend from the same terminus of the transposon, TnA, in the same direction, but to different extents, and to retain the TnA region intact . Insertions of a duplicate TnA element were found in R6K plasmids isolated from strains selected for increased ampicillin resistance, which were unstable in recA+ strains . In four plasmids examined after transfer to a recA host, an inverted repeat of the preexisting TnA element was shown to have been inserted at a similar location and was in two instances associated with deletions which extended from the same direction as those described above . The deletions are ascribed to the result of recA+-dependent recombination between direct repeats of TnA. Mol Gen Genet, 1979 Jan 11, 168(3), 337 - 40 The contruction and replication properties of hybrid plasmids composed of the r-determinant of R100.1 and the plasmids pCRI and pSC201; Lane D et al.; We have cloned the entire r-determinant of the antibiotic resistance plasmid R100.1 on the plasmic vectors pCR1 and pSC201 . We find that the hybrid plasmids segregate from cultures in which replication of the vector is blocked . This suggests that the r-det is not capable of autonomous replication. Mol Gen Genet, 1979 Jan 5, 168(1), 1 - 25 Plasmid replication functions . II . Cloning analysis of the repA replication region of antibiotic resistance plasmid R6-5; Andres I et al.; R6-5 is a low copy number, conjugative, FII incompatibility group plasmid that has a molecular length of 102 kb and that specifies resistance against several antibiotics (chloramphenicol, fusidic acid, kanamycin, streptomycin and sulphonamide) and mercury salts . By means of in vitro cloning procedures, mini plasmids have been generated that contain a DNA segment from the essential region of R6-5 that is only 2.6 kb in length . This DNA segment, which consists of two PstI fragments that are adjacent in the parent plasmid, carries all genes and sequences required for the regulated replication and incompatibility properties of R6-5, including its origin of replication, OriV, an essential function that has been designated RepA, and the copy control function, Cop . Three different polypeptides, having monomer molecular weights of 23,000, 10,000 and 9,500 daltons, are synthesized in detectable quantities by minicells carrying pBR322 hybrid plasmids that contain DNA segments from the R6-5 essential region . A spontaneous deletion derivative of a pBR322 hybrid plasmid that carries the R6-5 origin of replication was isolated . Heteroduplex analysis of this derivative plasmid indicates that the deleted DNA segment carries the R6-5 replication origin and that its termini consist of short inverted repeat sequences. Nord Vet Med, 1979 Jan, 31(1), 20 - 4 Antibiotic resistance and transferable antibiotica resistance Escherichia coli isolated from calves on a modern farm with therapeutic problems and unsatisfactory management conditions; Farris AS et al.; On a farm with therapeutic problems and unsatisfactory management conditions, the occurrence of antibiotic resistance and transferable antibiotic resistance has been studied in E . coli isolated from calves which were 5 and 30 days old . Strains with resistance to up to seven antibiotics as well as transferable resistance against up to five antibiotics were recorded . On an average, 4.2 strains with different patterns and 4.0 different strains with transferable resistance were isolated from each calf . The corresponding figures previously found for healthy control calves were 1.6 and 1.1 strains, respectively . Resistance and transferable resistance were most common against sulphonamide and penicillin. Contrib Microbiol Immunol, 1979, 6, 122 - 36 In vivo transcription and translation of R-plasmid 538-1 DNA in Escherichia coli; Alton NK et al.; In vivo transcription and translation of R-plasmid 538-1 in E . coli was analyzed . Transcription of individual restriction fragments was determined qualitatively by utilizing the techniques developed by Southern (27), and quantitatively by carrying out DNA-RNA filter hybridization . The most active region of R-plasmid transcription in strains repressed for conjugal transfer was found to occur in the region of the R-plasmid carrying the antibiotic resistance genes . In plasmids derepressed for conjugal transfer, a high level of transcription from the transfer gene region was also observed . When strains carrying R538-1drd were induced with Hg++ a high level of transcription was observed from the region of the R-plasmid carrying the genes for Hgr . Hybrid ColE1 plasmids carrying restriction fragments from the antibiotic resistance region of R538-1 were segregated into minicells . Labeling of the minicells with 35S-methionine allowed identification of the proteins coded by the fragments . A limited number of proteins were detected, and several of these have been correlated with the antibiotic resistance genes carried by R538-1. Antibiotiki, 1978 Dec, 23(12), 1083 - 8 {Plasmids of antibiotic-resistant clinical strains of E . coli}; Vakulenko SB et al.; Analysis of 53 antibiotic resistant clinical strains of E . coli isolated from patients with various purulent inflammatory diseases is presented . According to the data of the electrophoretic study 83 per cent of them carried 2 to 6 plasmids . Thirteen of them carried the conjugation R-factor . The antibiotic resistance in the other strains was due to the non-conjugation plasmids. Eur J Biochem, 1978 Dec 1, 92(1), 279 - 87 Assembly of the mitochondrial membrane system: mutations in the pho2 locus of the mitochondrial genome of Saccharomyces cerevisiae; Coruzzi G et al.; Two mutants of Saccharomyces cerevisiae which show a loss of mitochondrial rutamycin-sensitive ATPase activity are described . Although phenotypically similar to mutants of the mitochondrial locus pho1 {F . Foury and A . Tzagoloff (1976) Eur . J . Biochem . 68, 113-119}, these mutants define a second ATPase locus on the mitochondrial DNA (designated pho2), which is genetically unlinked to pho1 . Analysis of recombination in crosses involving multiple antibiotic resistance markers indicates that the locus is in the segment of the genome between ery1 and oli2, very close to oli1 . In fact it is proposed that the oli1 and pho2 mutations are in the same gene . Supporting evidence for this proposal includes: 1 . The analysis of marker retention in petite mutants shows that the oli1 and pho2 loci were either retained or lost together in all cases . 2 . Recombination frequencies of 0.05% or less are observed in crosses between the oli1 and pho2 loci . 3 . When rho+ revertants are isolated from the pho2 mutants they frequently are oligomycin resistant . 4 . pho2 mutants have an altered subunit 9 of the ATPase complex. Antibiotiki, 1978 Dec, 23(12), 1094 - 7 {Lysozyme activity of pneumococci}; Bukharin OV et al.; Examination of 329 pneumococcal strains showed that 41.2 per cent of the cultures had lysozyme activity . The frequency of the lysozyme feature depended on the method used . The lysozyme active strains were more frequently isolated from patients than from healthy persons and characterized by antibiotic resistance . The lysozyme feature correlated with the pneumococcal virulence with respect to albino mice, capacity for capsule formaiton and resistance to phagocytosis. Mol Gen Genet, 1978 Nov 29, 167(2), 119 - 27 Restriction map of the antibiotic resistance plasmid R1drd-19 and its derivatives pKN102 (R1drd-19B2) and R1drd-16 for the enzymes BamHI, HindIII, EcoRI and SalI; Blohm D et al.; The conjugative R plasmid R1drd-19, mediating antibiotic resistance to ampicillin (Ap), chloramphenicol (Cm), kanamycin (Km), streptomycin (Sm) and sulfonamides (Su) was mapped using the restriction endonucleases BamHI, HindIII, EcoRI and SalI . BamHI generates 5 fragments (A-E) with molecular weights between 46 x 10(6) 0.25 x 10(6) dalton, and HindIII 8(A-H) between 42 x 10(6) dalton (representing mainly the RTF) and 0.25 x 10(6) dalton (representing the main part of the RTF) and 0.1 x 10(6) dalton . EcoRI recognises 17 sites and produces fragments (A-Q) with molecular weights between 11.7 and 0.1 x 10(6) dalton . SalI yields 7 fragments (A-G) of 16.5 to 2.0 x 10(6) dalton . A physical map was constructed from fragments obtained by partial digestion of R1drd-19 with one restriction enzyme, by double and triple digestion of the DNA with two or three enzymes with and without isolation of individual bands from preparative gels . In addition the restriction patterns of several mutants of R1drd-19 were compared with it . Evidence is presented which indicates that the derivatives of R1 investigated are generated by extended deletions, namely the copy mutant pKN102 which has lost the Km resistance, R1drd-16, which has lost all resistances other than Km and the Kms derivative of R1drd-16, which represents the pure RTF . The map of R1drd-19 is remarkably different from those of R100 and R6-5 . Its molecular weight was estimated to be 62.5 Md . The circular fragment order for BamHI is: A-C-B-D-E, for HindIII: A-D-C-B-F-H-E-G, for EcoRI: A-C-K-B-F-J-O-D-H-L-G-P-Q-N-I-E-M- and for SalI A-B-C-D-G-F-E. Mol Gen Genet, 1978 Nov 16, 167(1), 11 - 19 Instability of plasmid DNA sequences: macro and micro evolution of the antibiotic resistance plasmid R6-5; Timmis KN et al.; Detailed examination of the structure of cloned DNA fragments of the R6-5 antibiotic resistance plasmid has revealed a substantial degree of polynucleotide sequence heterogeneity and indicates that sequence rearrangements in plasmids and possible other replicons occur more frequently than has hitherto been appreciated . The sequences changes in cloned R6-5 fragments were shown in some instances to have occurred prior to cloning, i.e . existing in the original population of R6-5 molecules that was obtained from a single bacterial clone and by several different criteria judged to be homogeneous, and in others to have occurred either during the cloning procedure or during subsequent propagation of hybrid molecules . The molecular changes that are described involved insertion/deletion of the previously characterized IS2 insertion element, formation of a new inverted repeat structure probably by duplication of a preexisting R6-5 DNA sequence, sequence inversion, and loss and gain of restriction endonuclease cleavage sites. Genetics, 1978 Aug, 89(4), 615 - 51 Uniparental inheritance of mitochondrial genes in yeast: dependence on input bias of mitochondrial DNA and preliminary investigations of the mechanism; Birky CW Jr et al.; In Saccharomyces cerevisiae, previous studies on the inheritance of mitochondrial genes controlling antibiotic resistance have shown that some crosses produce a substantial number of uniparental zygotes, which transmit to their diploid progeny mitochondrial alleles from only one parent . In this paper, we show that uniparental zygotes are formed especially when one parent (majority parent) contributes substantially more mitochondrial DNA molecules to the zygote than does the other (minority) parent . Cellular contents of mitochondrial DNA (mtDNA) are increased in these experiments by treatment with cycloheximide, alpha-factor, or the uvsp5 nuclear mutation . In such a biased cross, some zygotes are uniparental for mitochondrial alleles from the majority parent, and the frequency of such zygotes increases with increasing bias . In two- and three-factor crosses the cap1, ery1, and oli1 loci behave coordinately, rather than independently; minority markers tend to be transmitted or lost as a unit, suggesting that the uniparental mechanism acts on entire mtDNA molecules rather than on individual loci . This rules out the possibility that uniparental inheritance can be explained by the conversion of minority markers to the majority alleles during recombination . Exceptions to the coordinate behavior of different loci can be explained by marker rescue via recombination . Uniparental inheritance is largely independent of the position of buds on the zygote . We conclude that it is due to the failure of minority markers to replicate in some zygotes, possibly involving the rapid enzymatic destruction of such markers . We have considered two general classes of mechanisms: (1) random selection of molecules for replication, as for example by competition for replicating sites on a membrane; and (2) differential marking of mtDNA molecules in the two parents, possibly by modification enzymes, followed by a mechanism that "counts" molecules and replicates only the majority type . These classes of models are distinguished genetically by the fact that the first predicts that the output frequency of a given allele among the progeny of a large number of zygotes will approximately equal the average input frequency of that allele, while the second class predicts that any input bias will be amplified in the output . The data suggest that bias amplification does occur . We hypothesize that maternal inheritance of mitochondrial or chloroplast genes in many organisms may depend upon a biased input of organelle DNA molecules, which usually favors the maternal parent, followed by failure of the minority (paternal) molecules to replicate in many or all zygotes. Mol Gen Genet, 1978 Jul 25, 163(3), 257 - 75 Restriction enzyme analysis of mitochondrial DNAs of petite mutants of yeast: classification of petites, and deletion mapping of mitochondrial genes; Lewin A et al.; We have analyzed the restriction digest patterns of the mitochondrial DNA from 41 cytoplasmic petite strains of Saccharomyces cerevisiae, that have been extensively characterized with respect to genetic markers . Each mitochondrial DNA was digested with seven restriction endonucleases (EcoRI, HPaI, HindIII, BamHI, HhaI, SalI, and PstI) which together make 41 cuts in grande mitochondrial DNA and for which we have derived fragment maps . The petite mitochondrial DNAs were also analyzed with HpaII, HaeIII, and AluI, each of which makes more than 80 cleavages in grande mitochondrial DNA . On the basis of the restriction patterns observed (i.e., only one fragment migrating differently from grande for a single deletion, and more than one for multiple deletions) and by comparing petite and grande mitochondrial DNA restriction maps, the petite clones could be classified into two main groups: (1) petites representing a single deletion of grande mitochondrial DNA and (2) petites containing multiple deletions of the grande mitochondrial DNA resulting in rearranged sequences . Single deletion petites may retain a large portion of the grande mitochondrial genome or may be of low kinetic cimplexity . Many petites which are scored as single continuous deletions by genetic criteria were later demonstrated to be internally deleted by restriction endonuclease analysis . Heterogeneous sequences, manifested by the presence of sub-stoichiometric amounts of some restriction fragments, may accompany the single or multiple deletions . Single deletions with heterogeneous sequences remain useful for mapping if the low concentration sequences represent a subset of the stoichiometric bands . Using a group of petites which retain single continuous regions of the grande mitochondrial DNA, we have physically mapped antibiotic resistance and mit- markers to regions of the grande restriction map as follows: C (99.3--1.4 map units)--OXI-1 (2.5--15.7)--OXI-2 (18.5--25)--P (28.1--34.2)--OXI-3 (32.2--61.2--OII (60--62)--COB (64.6--80.8--0I (80.4--85.7)--E (95--98.9). Mol Gen Genet, 1978 Jul 25, 163(3), 241 - 55 Physical mapping of genes on yeast mitochondrial DNA: localization of antibiotic resistance loci, and rRNA and tRNA genes; Morimoto R et al.; We have physically mapped the loci conferring resistance to antibiotics that inhibit mitochondrial protein synthesis (erythromycin, chloramphenicol and paromomycin) or respiration (oligomycin I and II), as well as the 21s and 14s rRNA and tRNA genes on the restriction map of the mitochondrial genome of the yeast Saccharomyces cerevisiae . The mitochondrial genes were localized by hybridization of labeled RNA probes to restriction fragments of grande (strain MH41-7B) mitochondrial DNA (mtDNA) generated by endonucleases EcoRI, HpaI, BamHI, HindIII, SalI, PstI and HhaI . We have derived the HhaI restriction fragment map of MH41-7B mit DNA, to be added to our previously reported maps for the six other endonucleases . The antibiotic resistance loci (antR) were mapped by hybridization of 3H-cRNA transcribed from single marker petite mtDNA's of low kinetic complexity to grande restriction fragments . We have chosen the single Sal I site as the origin of the circular physical map and have positioned the antibiotic loci as follows: C (99.5-1.Ou)--P (27-36.Ou)--OII (58.3-62u--OI (80-84u)--E (94.4-98.4u) . The 21s rRNA is localized at 94.4-99.2u, and the 14s rRNA is positioned between 36.2-39.8u . The two rRNA species are separated by 36% of the genome . Total mitochondrial tRNA labeled with 125I hybridized primarily to two regions of the genome, at 99.5-11.5u and 34-44u . A third region of hybridization was occasionally detected at 70--76u, which probably corresponds to seryl and glutamyl tRNA genes, previously located to this region by petite deletion mapping. Biochemistry, 1978 Jun 27, 17(13), 2567 - 73 Replication of antibiotic resistance plasmid R6K DNA in vitro; Inuzuka M et al.; A soluble extract prepared from cells of an Escherichia coli strain carrying the antibiotic resistance plasmid R6K is capable of carrying out the complete process of R6K DNA replication . DNA synthesis in vitro is dependent on the four deoxyribo- and ribonucleotide triphosphates and is sensitive to rifampin and streptolydigin, inhibitors of DNA-dependent RNA polymerase . The incorporation of deoxyribonucleotides into R6K DNA also is sensitive to actinomycin D, novobiocin, arabinofuranosyl-CTP, and N-ethylmaleimide . Kinetics of synthesis are linear for 60 to 120 min . Replication proceeds semiconservatively and supercoiled closed-circular DNA molecules are synthesized . Analysis by alkaline sucrose gradient centrifugation indicated that the early R6K DNA products contain DNA fragments of approximately 18 S in size, corresponding to the length between the R6K alpha origin of replication and the terminus of replication observed in vivo . Addition of exogenous supercoiled R6K DNA is inhibitory to the in vitro system, whereas the addition of R6K DNA in the form of relaxation complex stimulates R6K DNA synthesis to a small extent. Mol Gen Genet, 1978 Jun 14, 162(2), 121 - 37 Cloning and characterization of EcoRI and HindIII restriction endonuclease-generated fragments of antibiotic resistance plasmids R6-5 and R6; Timmis KN et al.; DNA fragments generated by the EcoRI of HindIII endonucleases from the low copy number antibiotic resistance plasmids R6 and R6-5 were separately cloned using the high copy number ColE1 or pML21 plasmid vectors and the insertional inactivation procedure . The hybrid plasmids that were obtained were used to determine the location of the EcoRI and HindIII cleavage sites on the parent plasmid genomes by means of electron microscope heteroduplex analysis and agarose gel electrophoresis . Ultracentrifugation of the cloned fragments in caesium chloride gradients localized the high buoyant density regions of R6-5 to fragments that carry the genes for resistance to streptomycin-spectinomycin, sulfonamide, and mercury and a low buoyant density region to fragments that carry the tetracycline resistance determinant . Functional analysis of hybrid plasmids localized a number of plasmid properties such as resistances to antibiotics and mercury and several replication functions to specific regions of the R6-5 genome . Precise localisation of the genes for resistance to chloramphenicol, kanamycin, fusidic acid and tetracycline was possible due to the presence of identified restriction endonuclease cleavage sites within these determinants . Only one region competent for autonomous replication was identified on the R6-5 plasmid genome and this was localized to EcoRI fragment 2 and HindIII fragment 1 . However, two additional regions of replication activity designated RepB and RepC, themselves incapable of autonomous replication but capable supporting replication of a linked ColE1 plasmid in polA- bacteria, were also identified. Mol Gen Genet, 1978 Jun 1, 162(1), 51 - 7 Isolation and characterization of the minimal fragment required for autonomous replication ("basic replicon") of a copy mutant (pKN102) of the antibiotic resistance factor R1; Kollek R et al.; The mini plasmids deriving from pKN102, a copy mutant of the antibiotic resistance factor R1drd-19 of E . coli, share a common DNA sequence of 2.6 kb, which carries the minimal functions for autonomous replication . By cloning of two PstI fragments of this region it could be demonstrated that the "basic replicon" is a DNA segment not larger than 1.8 kb, which carries the orgin of replication and the genetic information for at least two proteins . Protein F (NW=11.000 dalton) seems to be synthesed in larger amounts in minicells of E . coli than protein C (20.000) . Plasmids containing this isolated replicon of R1 are completely compatible with the parental plasmid R1drd-19. J Bacteriol, 1978 Jun, 134(3), 1039 - 45 Escherichia coli K-12 mutants deficient in uracil-DNA glycosylase; Duncan BK et al.; A new assay specific for uracil-DNA glycosylase is described, Escherichia coli mutants partially and totally deficient in uracil-DNA glycosylase activity have been isolated by using this assay in mass-screening procedures . These have been designated ung mutants . The ung gene maps between tyrA and nadB on the E . coli chromosome . T4 phage containing uracil in their DNA grow on the most glycosylase-deficient hosts but are unable to grow on wild-type bacteria . This provides a simple spot test for the ung genotype . The ung mutants show slightly higher rates of spontaneous mutation to antibiotic resistance . Taken together, these results suggest a central role for uracil-DNA glycosylase in the initiation of an excision repair pathway for the exclusion of uracil from DNA. J Bacteriol, 1978 Jun, 134(3), 1141 - 56 Construction and characterization of amplifiable multicopy DNA cloning vehicles derived from the P15A cryptic miniplasmid; Chang AC et al.; Construction and characterization of a class of multicopy plasmid cloning vehicles containing the replication system of miniplasmid P15A are described . The constructed plasmids have cleavage sites within antibiotic resistance genes for a variety of commonly employed site-specific endonucleases, permitting convenient use of the insertional inactivation procedure for the selection of clones that contain hybrid DNA molecules . Although the constructed plasmids showed DNA sequence homology with the ColE1 plasmid within the replication region, were amplifiable by chloramphenicol or spectinomycin, required DNA polymerase I for replication, and shared other replication properties with ColE1, they were nevertheless compatible with ColE1 . P15A-derived plasmids were not self-transmissible and were mobilized poorly by Hfr strains; however, mobilization was complemented by the pre