Characterization of Bacillus subtilis bacteriophages

Brodetsky, Anna M. (University of California, Los Angeles), and W. R. Romig. Characterization of Bacillus subtilis bacteriophages. J. Bacteriol. 90:1655-1663. 1965.-A group of six phages, SP5, SP6, SP7, SP8, SP9, and SP13, which use the Marburg strain of Bacillus subtilis as host was characterized. These phages, referred to as group 1, were examined for the following properties: host range, plaque morphology, stability, adsorption kinetics, one-step growth characteristics, calcium requirements, serum neutralization, thermal inactivation, and inactivation by ultraviolet irradiation. Five unrelated B. subtilis phages, SP3, SP10, PBS1, SP alpha, and SP beta, were included in the studies. When first isolated, none of the group 1 phages was able to replicate efficiently on B. subtilis SB19, a mutant of the "transforming" B. subtilis 168. Host range mutants capable of growth in SB19 were isolated for all of the group 1 phages except SP13, and are designated the "star" phages (SP5* through SP9*). For characterization, SB19 was used as host for the star phages, and another B. subtilis mutant, 168B, was host for SP13.     

两株枯草芽孢杆菌的噬菌体

从三门峡酶制剂厂分离到与过去形态不同的两种噬菌体BS3l和BS32。BS31有收缩尾鞘,头部为六边形;BS32有复杂的短尾,形态与φ29相似,寄主范围窄且有差异,用限制酶分析,噬菌体DNA的分子量分别为62kb和17kb。根据解链温度计算噬菌体DNA的G十c含量分别为45．7mol％和40．7mol％。两株噬菌体的结构蛋白经SDS聚丙烯酰胺凝胶电沫测定,BS3l有2条主带,10条次带;BS32有3条主带和6条次带。     

Bacillus polymyxa bacteriophages from Brazilian soils

Ten phages of Bacillus polymyxa were isolated from four different Brazilian soils. All were dsDNA-containing phages belonging to Bradley types A and B. Data obtained from electron microscopy and tests of resistance against physical and chemical agents showed that the isolates could be distributed among six different groups. Host range data were in agreement with this classification. When tested against 88 strains of 18 Bacillus species, these phages only infected B. polymyxa strains, thus revealing specificity for this species. Three phage groups lysed all 42 available B. polymyxa strains and are suggested for use in rapid identification of this species.This work was sponsored by the National Research Council of Brasil (CNPq) and CAPES.     

Three Bacillus anthracis bacteriophages from topsoil

Three Bacillus anthracis bacteriophages from Iowa topsoil are characterized as to latent period, morphology, structural proteins, DNA size, and restriction endonuclease digestion. Electron micrographs indicate that the three isolates include two members of the Myoviridae and one smaller phage belonging to the Podoviridae. Phages Nk and DB resemble Myoviridae phage SP50 in morphology, but host range studies, protein, and DNA analysis indicate that both differ from SP50. Phage MH is very similar to phage phi 29, but differs in terms of host range, structural protein, and DNA characteristics.     

Sporulation-converting bacteriophages for Bacillus pumilus.

Thirty-three sporulation-converting bacteriophages for Bacillus pumilus NRS576 were assigned to two apparently unrelated groups on the basis of morphology and antiserum neutralization. Bacterial sporulation mutants responded similarly (conversion or nonconversion) to representatives of both phage groups. Evidence is presented indicating that PMB1 and related phages specify a restriction and/or modification system.     

Characterization of some pneumococcal bacteriophages.

The growth of pneumococcal phages at high cell and phage densities is enhanced strongly by the substitution of potassium for sodium in the medium. Initial titers of 2 X 10(10) to 4 X 10(10) PFU/ml are readily obtained, and concentrated stocks are stable in a storage buffer described here. The mechanism of the cation effect is obscure. Phages omega3 and omega8 each have linear double-stranded DNA of 33 X 10(6) daltons per particle, with an apparent guanine plus cytosine content of 47 to 49 mol%, as determined by buoyancy and melting temperature, but with an unusual absorbance spectrum. Efficiency of plating is high if sufficient time is allowed for a relatively slow adsorption, which differs several-fold in rate between the two phages. Morphologically, these and other pneumococcal phages are similar to coliphage lambda but with a longer tail and tail fiber. Upon UV inactivation, omega3 and omega8 have D37 values of 33 and 55 J/m2, respectively, and each shows multiplicity reactivation. A total of 13 ts mutants have been isolated from the two phages, representing only two complementation groups; complementation and recombination occur between omega3 and omega8 mutants. Both phages provoke high-titer antisera with extensive cross-reactivity against a number of newly isolated pneumococcal phages.     

Host cell reactivation of Bacillus subtilis bacteriophages.

Host cell reactivation of ultraviolet-irradiated phage can be used as a probe of the bacterial repair system and to determine phage and cellular contributions to the repair process. Using the Bacillus subtilis phages SPP1, SP01, phie, and phi29, we found that the uvr-1 and polA functions are involved in the host cell reactivation of the four phages. SPP1 was the only phage whose reactivation was also decreased in recA, recD, and recF mutant cells. We studied variations of host cell reactivation for SPP1 during spore outgrowth; at high ultraviolet doses the activity of a spore repair system requiring deoxyribonucleic acid polymerase I became evident. The spore repair system was completely replaced by the vegetative one by 120 min of outgrowth.     

Structure and assembly of filamentous bacteriophages

Filamentous bacteriophages are interesting paradigms in structural molecular biology, in part because of the unusual mechanism of filamentous phage assembly. During assembly, several thousand copies of an intracellular DNA-binding protein bind to each copy of the replicating phage DNA, and are then displaced by membrane-spanning phage coat proteins as the nascent phage is extruded through the bacterial plasma membrane. This complicated process takes place without killing the host bacterium.     

Variability of Bacillus thuringiensis bacteriophages with C2-morphology

Biological as well as physicochemical properties of Bacillus thuringiensis bacteriophages "17" and "7/13" having C2-morphology and isolated from factory phagolysates were studied. The bacteriophages are identical in the lytic spectrum++, morphology, size, GC-content, have the same buoyant density. The physical map for restriction endonucleases EcoRI, HindIII, SalGI and MvaI has been constructed of the bacteriophages DNA. Heteroduplex analysis has revealed the nonhomologous region of the deletion-insertion type as a 0.8 Md loop. The bacteriophages "17" and "7/13" are concluded to be closely related but not identical.     

Structure of DNA within three isometric bacteriophages.

This paper describes a model for the structure of DNA contained in three morphologically similar bacteriophages--T7, P22 and phiCd-1--based on the transient electric dichroism of intact phage. The reduced dichroism of each of the phages at perfect orientation is within the range +0.12 to +0.19. Assuming that the phage orientation axis is that which passes from the apex through the tail, the measured dichroism suggests that DNA is wrapped in closely packed, co-axial solenoids with the axis of the solenoids tipped 43.5 degrees +/- 2.5 degrees from the orientation axis of the phage. All three phages show a large permanent dipole moment, with respective values of 5600, 200,000 and 500,000 Debye for T7, phiCd-1 and P22. The radius of the equivalent sphere for the three phages calculated from the rotational relaxation time for the rise of dichroism is in agreement with birefringence and electron microscope observations. The circular dichroism spectra of all three bacteriophages indicate that the local DNA helicity is similar in each case.     

The isolation and characterization of bacteriophages infecting obligately thermophilic strains of Bacillus

Twenty-four thermophilic bacteriophages have been isolated from diverse sources such as compost, soil, silage and rotting straw. Although considerable individual host specificity was observed, the phages were able to infect most of the major taxonomic groups of Bacillus thermophiles. The phages varied considerably in morphology and size; the phage heads were either cylindrical or polyhedral with tails varying in length between 15 and 500 nm. Most of the phages were stable at 50 degrees C for 4-5 h but at 70 degrees C the plaque-forming units decreased by between 10(2)- and 10(7)-fold in 2 h. The DNA of morphologically similar phages was examined by restriction enzyme analysis, and some differences in the DNA fragment patterns were found. Efficiency of plating data indicated that 'B. caldotenax' has a restriction and modification system. These phages may be valuable for the study of the genetics of thermophilic bacilli: transduction of 'B. caldotenax' and 'B. caldovelox' by phage JS017 has been observed.