TITLE:
Influence of Hot Spring Phages on Community Carbon Metabolism: Win, Lose or Draw?
AUTHORS:
Raymond Kepner
KEYWORDS:
Hot Springs, Virus, Prophage, Thermophiles, Carbon Metabolism
JOURNAL NAME:
Advances in Microbiology,
Vol.5 No.9,
August
27,
2015
ABSTRACT: Abundant virus-like particles were concentrated from large-volume samples
from two hot springs. Both addition of viral concentrates and addition of
samples induced by addition of mitomycin-C changed patterns of carbon source
utilization by hot spring microbial communities. Specific effects of the two
treatments depended upon both temperature and incubation period. Increased
metabolic capability with greater exposure to free phages, consistent with the
view that phages are major lateral transporters of metabolic genes, was
observed most clearly in microbes incubated at a temperature lower than that
encountered in situ. On the other
hand, decreases in the diversity of utilizable C sources upon exposure to
phages may have been due to lytic activity in which susceptible bacterial
populations were differentially reduced by infective viruses, consistent with
the “killing the winner” hypothesis.
Treatment of cultures with MC-treated culture extracts, assumed to increase
exposure to excised prophages, resulted in higher average metabolic rates after
18 h, but lower rates after 48 h of incubation. With incubation at in situ temperature, this same treatment
led to an initial increase in the number of readily utilized C sources,
followed by a decrease in community metabolic diversity relative to controls in
samples from both hot springs. Thus, treatments designed to increase the
interaction between hot spring microbes and either free or newly-excised phages
had observable time- and temperature-dependent effects on community metabolism,
demonstrating an important, yet complex, ecological role for phages in hot
spring waters.