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In our study we searched for an association between the insertion/deletion (I/D) polymorphism at the ACE locus as well as apo A-I promoter polymorphism and coronary artery disease (CAD) in patients with familial hypercholesterolemia (FH). 34 FH patients over 40 years were ascertained; 16 patients with CAD were compared with 18 patients without CAD. There was an excess of DD or ID genotype in FH patients with CAD (OR = 4.9, CI = 1.17-22.17; Fisher exact p = 0.012), however, no association between G to A substitution in the promoter region of the apo A-I gene and CAD was found. Our results suggest that the DD/ID genotype at the ACE gene locus might be an important genetic risk factor for CAD in FH patients.

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Complement activation and serum resistance of the Borrelia burgdorferi strains B31 (American strain) and PKo (European strain) were compared. In 25% (v/v) normal human serum (NHS) free of B. burgdorferi-specific antibodies the cells of the PKo strain were high activators of complement as indicated by rapid and strong C9 consumption, by deposition of up to 336763 C9 molecules per cell and by the formation of the terminal complement complex on the cell surface. By comparison, complement activation by the B31 strain was low with 5.4-fold less C9 deposited per cell. The addition of B. burgdorferi-specific antibodies to NHS either as purified IgG or heat-inactivated patient sera, had no influence on the results with both strains. After an incubation period of 2h at 37 degrees C in 25% (v/v) NHS most cells of the PKo strain had lost their viability as indicated by cell immobilization and failure to multiply in subcultures. In addition, extensive cell fragmentation and bleb formation were observed in the electron microscope. In contrast, the B31 strain remained alive and morphologically intact after the same incubation with NHS. We conclude from our results that complement activation and serum resistance are properties which differ considerably between isolated strains of B. burgdorferi.

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High mol. wt. DNA was extracted from Escherichia coli lambda lysogens and was shown to be infectious. Its infectivity was due to prophage DNA integrated into the host chromosome rather than to DNA released from mature phage particles, as established by the following criteria: the titre of infectious DNA exceeded by 100-fold the titre of infectious units present before DNA extraction; mild shear selectively reduced prophage DNA infectivity to 2% of the unsheared DNA while lambda phage DNA infectivity retained 50% of its infectivity; DNA extracted from an E. coli (lambda c857 tsxisam6) lysogen yielded 200 times as many plaques on sup+ than on sup- spheroplasts. Thus lambda prophage DNA infectivity depends on expression of the excision gene while the infectivity of non-integrated forms of lambda does not. About 10(4) genome equivalents of E. coli DNA yielded one infectious centre unit in this assay system; this high infectivity should make prophage DNA a useful marker in genetic transformation experiments.

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Sodium polyanetholsulfonate (SPS) at a final concentration of at least 250 microng/ml (0.025%) was required for inhibition of the bactericidal activity of 80% (vol/vol) of fresh human serum against "promptly serum-sensitive" strains of Serratia marcescens and control strain Escherichia coli C, i.e., for inhibition of the classical pathway of complement activation. In contrast, SPS at 125 microng/ml (0.0125%) was sufficient for neutralization of the bactericidal activity of 80% (vol/vol) fresh human serum against "delayed serum-sensitive" strains of S. marcescens known to activate the alternative pathway of human complement. Addition of up to 500 microng of SPS per ml to 80% (vol/vol) fresh human serum failed to neutralize transferrin-mediated, "late" bacteriostasis against control strain E. coli C, an effect that was demonstrable only after prolonged, i.e., overnight, incubation of the test strain. However, this late inhibitory effect against E. coli C was not observed in SPS-treated 20% (vol/vol) fresh human serum or in 10 or 20% (vol/vol) conventionally heat-inactivated human serum. Immunoelectrophoretic examination disclosed that SPS did not precipitate transferrin from either fresh or heat-inactivated human serum. Thus, SPS, at 250 microng/ml, was demonstrated to be sufficient for the inhibition of both classical and alternative complement pathway-activated bactericidal activity of 80% (vol/vol) human serum. However, SPS at a concentration of 500 microng/ml failed to antagonize one antimicrobial system of 80% (vol/vol) human serum, namely transferrin-mediated bacteriostasis.

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The H-immobilization test of Le Minor for determining flagellar (H) antigens was evaluated and compared with tube and slide H-agglutination tests. The test proved specific and easy to perform, and titration end points were clearly discernible. The degree of serological cross-reactivity between H antigen reference strains of Serratia marcescens was low. Consequently, this test was adopted for routine serological analysis of H antigens, using unabsorbed rabbit immune anti-H sera. As a result of using this procedure, three new provisional H antignes, designated H14, H15, and H16, are proposed.

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Chelation of fresh human serum with 0.01 M MgCl2 (Mg) plus 0.01 M ethylene glycol tetraacetic acid failed to abrogate the bactericidal activity against "delayed serum-sensitive" strains of Serratia marcescens, whereas previously "promptly serum-sensitive" strains of S. marcescens and control strain Escherichia coli C were killed after an extended period of incubation. The addition of 0.01 M ethylenediametetracetate to fresh human serum neutralized bactericidal activity against S. marcescens of either serum sensitivity category.

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Neutralization tests with rabbit hyperimmune sera revealed a close, if not identical, serological relationship among 7 group A (phage tail) bacteriocins of Serratia marcescens of subgroup I, and among 3 phage tail bacteriocins of subgroup II, respectively. On the other hand, subgroup I and II phage tail bacteriocins were found to be serologically unrelated, as determined with neutralization tests and Ouchterlony immunodiffusion experiments. Immunoelectrophoretic tests, employing a representive phage tail bacteriocin of each of the two subgroups, disclosed the electrophoretic mobility of bacteriocin no. 5 (subgroup I), whereas bacteriocin no. 16 (subgroup II) remained stationary. Thus, two additional differential criteria, i.e., differences in antigenicity and electrophoretic mobility, were obtained for the characterization of subgroup I and II group A (phage tail) bacteriocins of S. marcescens.

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The biological activity of subgroup II group A (phage tail) bacteriocins of Serratia marcescens against susceptible indicator cells was completely abolished on two defined, Agarose-containing media. The addition of 0.002 M CaC12 to these two media fully restored the lethal activity of these phage tails. Subgroup I phage tail bacteriocins, on the other hand, were found to have no requirement for divalent cations. These observations furnished an additional biological criterion for the differentiation of subgroup I and II phage tail bacteriocins of S. marcescens.

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A multiple drug-resistant strain of Serratia marcescens (bacteriocin type 18) was isolated from three clinical patients. The isolates were found to carry a conjugally nontransferable, nonmobilizeable resistance plasmid (R-plasmid) with resistance-(r)-determinants against ten antimicrobial drugs: ampicillin, carbenicillin, chloramphenicol, gentamicin, kanamycin, neomycin, streptomycin, tobramycin, triple sulfonamides, cotrimoxazole, and--possibly--nalidixic acid, as determined with exposure to 'curing' agents (ethidium bromide, acridine orange, and sodium dodecyl sulfate) and by the high rate of spontaneous loss of r-determinants. Dyebuoyant density centrifugation allowed recovery of R-plasmid DNA that measured roughly 24 mum in contour length; after 'curing' with concomitant loss of 9 r-determinants, the contour length of the R-plasmid DNA of one isolate (No. SE 154) had decreased to roughly 15 mum, and none was detected in the sole variant of the isolate that spontaneously had lost 11 r-determinants.

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Exposure of Serratia marcescens cells to 10, 5, and 2.5 mug/ml of polymyxin B resulted in outer cell surface alterations that consisted of coarse, pleomorphic projections which revealed a double-contoured membrane structure. In contrast, fresh, but not heat-inactivated human serum caused the deposition of very fine, thread-like aggregates on the outer cell surface of exposed cells. The combination of polymyxin B and fresh human serum caused clearly discernible ultrastructural changes of the polymyxin and the fresh serum type, respectively.

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The combination of polymyxin B and rifampin resulted in an additive effect against all 12 clinical isolates of Serratia marcescens examined, including multiple-drug-resistant isolates.

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Two H2S producing, multiple drug-resistant variants of Escherichia coli were isolated from clinical urine specimens. Both isolates transferred, eleven resistance determinants to recipient strains of E. coli K 12 and nine r-determinants to Klebsiella pneumoniae recipients; in no instance was transfer of the 'curing'-refractory H2S marker demonstrable.

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Two of twelve examined S. marcescens strains were promptly killed by 80% (v/v) fresh human serum (within 20 min), analogous to a serum-sensitive control strain of Escherichia coli; ten strains, however, were killed by fresh serum only after extended incubation (2-4 h). The combination of therapeutically achievable concentrations of polymyxin B (range 5 to 1.25 mug/ml) and fresh, but not heat-inactivated human serum was found to exert an accelerated, additive effect against 9 of 10 'delayed serum-sensitive' isolates of S. marcescens, an organism that is characterized by intrinsic resistance against polymyxins. The combination of 80% (v/v) fresh, defibrinated human blood and polymyxin B likewise resulted in an additive effect. Polymyxin B treatment of S. marcescens strains caused a prompt, marked, though reversible bile salt susceptibility of the cells; in contrast, the effect induced by fresh serum was slight and not apparent until several hours after exposure.

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