Transducing Bacteriophage for Bacillus cereus

A phage, designated CP-51, that carries out generalized transduction in Bacillus cereus 569 was isolated from soil. All auxotrophic mutants tested, those requiring tryptophan, histidine, leucine, isoleucine, methionine, or phenylalanine, were transduced to prototrophy. The phage was extremely unstable when stored at 2 to 4 C, but stability was enhanced by storage at higher temperatures. The optimal temperature of those tested for maintenance of plaque-forming units was 15 C.     

New Generalized Transducing Bacteriophage in Echerichia coli

A new generalized transducing bacteriophage similar to P1 was isolated from Salmonella oranienburg.     

Isolation and Characterization of φ80 Transducing Bacteriophage for a Ribonucleic Acid Polymerase Gene

A new method for isolating specialized transducing phages is described. It was used to isolate a group of phi80 transducing phages which carry various bacterial markers from the metB region of the Escherichia coli chromosome. Some of the phages selected for transduction of the supA36 marker were also shown to carry rif, a locus known to specify the beta subunit of ribonucleic acid polymerase. Expression of the prophage rif(r) gene in lysogens was demonstrated by its ability to confer rifampin resistance on part of the cellular ribonucleic acid polymerase pool.     

Bacteriophage DNA: Correlation of Buoyant Density, Melting Temperature, and the Chemically Determined Base Composition

The mathematical relationships between the buoyant density, melting temperature, and chemically determined base composition of bacteriophage DNA are described and compared with regression equations derived from studies with bacterial DNA.     

Bactericidal Genes of Staphylococcal Bacteriophage Sb-1

Bacteriophage genes offer a potential resource for development of new antibiotics. Here, we identify at least six genes of Staphylococcus aureus phage Sb-1 that have bactericidal activity when expressed in Escherichia coli. Since the natural host is gram-positive, and E. coli is gram-negative, it is likely that a variety of quite different bacterial pathogens would be susceptible to each of these bactericidal activities, which therefore might serve as the basis for development of new wide-spectrum antibiotics. We show that two of these gene products target E. coli protein synthesis.     

Reproducibility of Staphylococcal Bacteriophage Types by Use of Different Concentrations of Bacteriophage

A comparative investigation was carried out on the reproducibility of staphylococcal bacteriophage types at 100 routine test dilution (RTD) and at the conventional concentrations, RTD and 1,000 RTD. The comparison includes multiple typing of laboratory strains and duplicate isolates from hospital patients. No significant difference was found in the reproducibility of the types at the different concentrations. A single concentration corresponding to 100 RTD is recommended for routine use in phage typing as a possible substitute for typing with two different concentrations.     

Bacteriophage Particles with Endo-Glycosidase Activity

Some Escherichia coli K bacteriophage particles, capable of interacting specifically with bacterial polysaccharide capsules, carry an endo-glycosidase activity, probably located in the spikes.     

Growth and Cultivation of the Unusual Generalized Transducing Bacillus Bacteriophage SP-15

Additional properties of SP-15, a generalized transducing bacteriophage notable for the ability to transfer an unusually large fragment of deoxyribonucleic acid (DNA) to Bacillus subtilis and B. licheniformis, are presented together with improved methods that enhance its utility. Simple means have been found to provide the rigid control over moisture that is necessary for the assay of plaque-forming units (PFU). Reproducible procedures for propagating transducing phage, which depend upon an appropriate mixing of PFU with uninfected bacteria, have replaced less reliable methods that utilized infected spores. Transduction of B. subtilis W-23 increased linearly when MgSO(4) in recipient cell-SP-15 mixtures was increased from 0.005 to 0.03 m. Methods have been developed that protect SP-15 from the damaging effects of CsCl and of osmotic shock subsequent to dilution. Evidence that the PFU and transducing particles of lysates decay at the same slow rate during extended storage suggests that the decay is a result of damage to protein rather than to DNA. One-step growth experiments, in which SP-15 was propagated on B. subtilis W-23-S(r)/1 mg, indicated a latent period of 100 min, a rise period of 60 min, and a burst size of 25 to 34 PFU per infected cell. These findings suggest explanations for some of the technical difficulties SP-15 has presented.     

Rapid Method of Determining Coagulase Activity During Staphylococcal Bacteriophage Typing

The plate test, a modification of the slide test described by Cadness-Graves was developed for the rapid identification of coagulase-positive staphylococci in conjunction with bacteriophage typing. An evaluation of 1,145 cultures by three coagulase-determination methods, the slide, tube, and plate tests, indicates that the plate test is as accurate as the slide tests, and the plate test agrees 97.7% with the tube test.     

Buoyant Density and Satellite Composition of DNA of Mouse Heterochromatin

Ten per cent of mouse DNA occurs as a satellite band with a buoyant density lighter than that of the main band¹. This satellite contains highly repetitious DNA^2,3. It has been shown that the amount of satellite is markedly increased in DNA isolated from the heterochromatin fraction of mouse nuclei⁴. Furthermore, in situ hybridization studies have shown that satellite DNA is localized to the pericentromeric heterochromatin of all the mouse chromosomes except the Y^5,6. These observations demonstrate an intimate association between mouse satellite DNA and heterochromatin and they raise the question: is all the DNA from mouse heterochromatin composed of satellite DNA or is a significant portion composed of non-satellite DNA?     

Buoyant Density of the Hepatitis A Virus-Like Particle in Cesium Chloride

We recently visualized by immune electron microscopy a virus-like particle in the stools of patients with hepatitis A. The particle measured approximately 27 nm in diameter and morphologically resembled a picornavirus or parvovirus. To further characterize this particle, we have determined its buoyant density in cesium chloride (CsCl) by ultracentrifugation. Hepatitis A particles from three positive stool specimens were isopycnically banded in separate experiments, and the gradient fractions were examined for particles by immune electron microscopy by using hepatitis A convalescent sera. In each experiment, the particles were observed in a normal distribution about a peak fraction with a mean density of approximately 1.4 g/cm(3). The buoyant density of 1.4 g/cm(3) in CsCl together with its morphology and the reported resistance of hepatitis virus to acid, ether, and heat suggest that this particle is parvovirus-like.     

Bacteriophage phi 80-induced low molecular weight RNA

A species of low molecular weight RNA (M₃) which is produced in bacteriophage φ80-infected Escherichia coli has been isolated and characterized. M₃ appears immediately after infection and its synthesis continues until lysis. This RNA is unstable; its mean half-life is 13.5 min. The structural gene for M₃ is localized on the φ80 genome to the right of the exonuclease locus and to the left of gene Q.     

Prevention of Staphylococcal Bacteriophage Activity by Antigen A Precipitins in Human Sera

Antigen A precipitins in human sera prevented plaque formation and propagation of staphylococcal bacteriophages. Over 20% of total IgG was removed from human sera by absorption with staphylococci containing antigen A. The specific precipitating antibody in rabbit antisera formed lines of idenity with antigen A precipitins in lower dilutions of human sera but formed lines of nonidenity with antigen A precipitins in higher dilutions of the same sera, suggesting both specific and nonspecific antigen A precipitins in human sera. The specific and nonspecific antigen A precipitins in human sera may prevent the in vivo activity of staphylococcal bacteriophages which have been demonstrated previously in animals whose sera do not contain either specific or nonspecific antigen A precipitins.     

Organization of Bacteriophage Tail-Like Particles in Cells of Chromobacterium violaceum

A strain of Chromobacterium violaceum has been isolated which produces bacteriophage tail-like particles in high numbers. The extracellular morphology and the intracellular arrangement of these particles are described.     

Inactivation of Staphylococcal Phenol Soluble Modulins by Serum Lipoprotein Particles

Staphylococcus aureus virulence has been associated with the production of phenol soluble modulins (PSM). PSM are known to activate, attract and lyse neutrophils. However, the functional characterizations were generally performed in the absence of human serum. Here, we demonstrate that human serum can inhibit all the previously-described activities of PSM. We observed that serum can fully block both the cell lysis and FPR2 activation of neutrophils. We show a direct interaction between PSM and serum lipoproteins in human serum and whole blood. Subsequent analysis using purified high, low, and very low density lipoproteins (HDL, LDL, and VLDL) revealed that they indeed neutralize PSM. The lipoprotein HDL showed highest binding and antagonizing capacity for PSM. Furthermore, we show potential intracellular production of PSM by S. aureus upon phagocytosis by neutrophils, which opens a new area for exploration of the intracellular lytic capacity of PSM. Collectively, our data show that in a serum environment the function of PSM as important extracellular toxins should be reconsidered.