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Biological characterization of induced phages from Saccharopolyspora hirsuta 367 and comparison with phage JHJ-1
L R Gaudreau1, J M Lavoie, C V Déry
1Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Québec, Canada.
Abstract:
Phages JHJ-2 and JHJ-3 were isolated from Saccharopolyspora hirsuta 367 UC 8106 following induction with mitomycin C and amplified on S. hirsuta NRRL B-5792. Their properties were compared with those of phage JHJ-1, isolated previously from S. hirsuta 367 NRRL 12045. The DNA restriction patterns appeared to be identical. One-step growth experiments showed no differences between the replication cycles. Burst sizes ranged from 100 to 110 p.f.u. per cell. However, the three phages showed some differences in their behaviour in different hosts. The host range of phage JHJ-1, on non-lysogenic strains, was emended to include all of the Saccharopolyspora strains tested; the host range of phage JHJ-2 was shown to be identical to JHJ-1. Phage JHJ-3 did not form detectable plaques on strains of S. rectivirgula or S. erythraea except S. erythraea NRRL 2359. Neither phage JHJ-2 nor JHJ-3 formed plaques on any lysogenic strains, while JHJ-1 formed plaques on all such strains except S. hirsuta 367 UC8106. Phage JHJ-3 was characterized as a temperate bacteriophage because it formed turbid, self-limiting plaques and lysogenized S. hirsuta NRRL B-5792. It was spontaneously released from UC8106. Both JHJ-1 and JHJ-2 formed clear and invasive (Inv+ phenotype: the property to grow on old mycelium) plaques on some Saccharopolyspora strains but clear and self-limiting plaques on others. Thus, the expression of the Inv+ phenotype encoded by JHJ-1 and JHJ-2 appears to be modulated by the host cell.
Insights
Three Saccharopolyspora phages, JHJ-1, JHJ-2, and JHJ-3, were compared. While genetically similar, they exhibited distinct host ranges and behaviors, with host modulation influencing phage phenotypes.
Area of Science:
- Microbiology
- Virology
- Bacteriology
Background:
- Bacteriophages are viruses that infect bacteria.
- Saccharopolyspora species are actinobacteria with agricultural and industrial relevance.
- Understanding phage-host interactions is crucial for phage therapy and genetic engineering.
Purpose of the Study:
- To isolate and characterize novel bacteriophages infecting Saccharopolyspora hirsuta.
- To compare the biological properties of newly isolated phages (JHJ-2, JHJ-3) with a previously identified phage (JHJ-1).
- To investigate the host range and phenotypic expression of these phages within the Saccharopolyspora genus.
Main Methods:
- Isolation of phages JHJ-2 and JHJ-3 from Saccharopolyspora hirsuta via mitomycin C induction.
- Amplification of phages on Saccharopolyspora hirsuta NRRL B-5792.
- Comparative analysis of DNA restriction patterns, one-step growth cycles, and burst sizes.
- Determination of host ranges on various Saccharopolyspora strains, including lysogenic and non-lysogenic variants.
- Characterization of plaque morphology and assessment of the invasive (Inv+) phenotype.
Main Results:
- Phages JHJ-1, JHJ-2, and JHJ-3 displayed identical DNA restriction patterns and replication cycles.
- Burst sizes for all three phages ranged from 100 to 110 plaque-forming units (p.f.u.) per cell.
- Significant differences were observed in host range; JHJ-1 and JHJ-2 infected most Saccharopolyspora strains, while JHJ-3 had a restricted host range.
- Phage JHJ-3 was confirmed as temperate, forming turbid plaques and lysogenizing S. hirsuta.
- The invasive (Inv+) phenotype of phages JHJ-1 and JHJ-2 was host-dependent, indicating modulation by the host cell.
Conclusions:
- Phages JHJ-1, JHJ-2, and JHJ-3 are closely related but exhibit distinct host interactions.
- Host cell machinery plays a role in modulating the expression of specific phage traits, such as the invasive phenotype.
- These findings contribute to the understanding of phage diversity and host specificity within Saccharopolyspora.