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Salinity regulation of the interaction of halovirus SNJ1 with its host and alteration of the halovirus replication strategy to adapt to the variable ecosystem.

Mei Y, He C, Huang Y, Liu Y, Zhang Z, Chen X, Shen P - PLoS ONE (2015)

Bottom Line: However, until now, the systematic studies on the halovirus ecology and the effects of salt concentration on virus-host systems are lacking.Our results also demonstrated that cells incubated at a high salt concentration prior to infection increased the ability of the virus to adsorb and lyse its host cells; therefore, the physiological status of host cells also affected the virus-host interaction.In conclusion, SNJ1 acted as a predator, lysing host cells and releasing progeny viruses in hypersaline environments; in low salt environments, viruses lysogenized host cells to escape the damage from low salinity.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan, Hubei, China.

ABSTRACT
Halovirus is a major force that affects the evolution of extreme halophiles and the biogeochemistry of hypersaline environments. However, until now, the systematic studies on the halovirus ecology and the effects of salt concentration on virus-host systems are lacking. To provide more valuable information for understanding ecological strategies of a virus-host system in the hypersaline ecosystem, we studied the interaction between halovirus SNJ1 and its host Natrinema sp.J7-2 under various NaCl concentrations. We found that the adsorption rate and lytic rate increased with salt concentration, demonstrating that a higher salt concentration promoted viral adsorption and proliferation. Contrary to the lytic rate, the lysogenic rate decreased as the salt concentration increased. Our results also demonstrated that cells incubated at a high salt concentration prior to infection increased the ability of the virus to adsorb and lyse its host cells; therefore, the physiological status of host cells also affected the virus-host interaction. In conclusion, SNJ1 acted as a predator, lysing host cells and releasing progeny viruses in hypersaline environments; in low salt environments, viruses lysogenized host cells to escape the damage from low salinity.

No MeSH data available.


Related in: MedlinePlus

The effect of salinity on the infective activity of halovirus SNJ1 and the growth of its host cells.(A) the remaining infective activity of halovirus SNJ1 under different NaCl concentrations at indicative time; ■,●,▲,▼, and ○ represent the remaining infective activity in 12%, 15%, 18%, 25%, and 30% NaCl, respectively. (B) the growth curves of Natrinema sp. J7-2 under different NaCl concentrations at indicative time; the symbols △, ■, ●, ▲, and ▼ denote the growth of the host cells in 12%, 15%, 18%, 25%, and 30% NaCl, respectively.
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pone.0123874.g001: The effect of salinity on the infective activity of halovirus SNJ1 and the growth of its host cells.(A) the remaining infective activity of halovirus SNJ1 under different NaCl concentrations at indicative time; ■,●,▲,▼, and ○ represent the remaining infective activity in 12%, 15%, 18%, 25%, and 30% NaCl, respectively. (B) the growth curves of Natrinema sp. J7-2 under different NaCl concentrations at indicative time; the symbols △, ■, ●, ▲, and ▼ denote the growth of the host cells in 12%, 15%, 18%, 25%, and 30% NaCl, respectively.

Mentions: The haloarchaeal strains and haloviruses flourish in hypersaline environments, and the salinity of the ecosystem affects their viability. To determine the effect of salinity on SNJ1, the remaining infective activities were executed. The infective activity decreased drastically within 24 h when the salinity was lower than 18%: 60.8% and 2.2% in 18% and 15% NaCl solutions after 24 h, respectively. In 12% NaCl solution, the infective activity was nearly zero (Fig 1A). Similar assays were used to determine the viabilities of the host cells within the same range of NaCl concentration. The growth of Natrinema sp J7-2 exhibited different growth rates in media containing variable salinities, and the host cells grew well in all media, except in 12% NaCl (Fig 1B). The highest growth rate was in 18% NaCl, followed by those in 25%, 30% and 15% NaCl. However, in 12% NaCl, the optical density at 550 nm, which was slightly increased after 72 h, was lower than 0.1. Interestingly, the optical density of cells in 12% medium increased to 0.5–0.6 after 11 days, which suggested that partial host cells were still alive, even when kept in 12% NaCl. Comparing the results of halovirus infective activities with host growth rates in various salinities, we found that the host cells were more tolerant to an altered NaCl concentration than SNJ1.


Salinity regulation of the interaction of halovirus SNJ1 with its host and alteration of the halovirus replication strategy to adapt to the variable ecosystem.

Mei Y, He C, Huang Y, Liu Y, Zhang Z, Chen X, Shen P - PLoS ONE (2015)

The effect of salinity on the infective activity of halovirus SNJ1 and the growth of its host cells.(A) the remaining infective activity of halovirus SNJ1 under different NaCl concentrations at indicative time; ■,●,▲,▼, and ○ represent the remaining infective activity in 12%, 15%, 18%, 25%, and 30% NaCl, respectively. (B) the growth curves of Natrinema sp. J7-2 under different NaCl concentrations at indicative time; the symbols △, ■, ●, ▲, and ▼ denote the growth of the host cells in 12%, 15%, 18%, 25%, and 30% NaCl, respectively.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4390326&req=5

pone.0123874.g001: The effect of salinity on the infective activity of halovirus SNJ1 and the growth of its host cells.(A) the remaining infective activity of halovirus SNJ1 under different NaCl concentrations at indicative time; ■,●,▲,▼, and ○ represent the remaining infective activity in 12%, 15%, 18%, 25%, and 30% NaCl, respectively. (B) the growth curves of Natrinema sp. J7-2 under different NaCl concentrations at indicative time; the symbols △, ■, ●, ▲, and ▼ denote the growth of the host cells in 12%, 15%, 18%, 25%, and 30% NaCl, respectively.
Mentions: The haloarchaeal strains and haloviruses flourish in hypersaline environments, and the salinity of the ecosystem affects their viability. To determine the effect of salinity on SNJ1, the remaining infective activities were executed. The infective activity decreased drastically within 24 h when the salinity was lower than 18%: 60.8% and 2.2% in 18% and 15% NaCl solutions after 24 h, respectively. In 12% NaCl solution, the infective activity was nearly zero (Fig 1A). Similar assays were used to determine the viabilities of the host cells within the same range of NaCl concentration. The growth of Natrinema sp J7-2 exhibited different growth rates in media containing variable salinities, and the host cells grew well in all media, except in 12% NaCl (Fig 1B). The highest growth rate was in 18% NaCl, followed by those in 25%, 30% and 15% NaCl. However, in 12% NaCl, the optical density at 550 nm, which was slightly increased after 72 h, was lower than 0.1. Interestingly, the optical density of cells in 12% medium increased to 0.5–0.6 after 11 days, which suggested that partial host cells were still alive, even when kept in 12% NaCl. Comparing the results of halovirus infective activities with host growth rates in various salinities, we found that the host cells were more tolerant to an altered NaCl concentration than SNJ1.

Bottom Line: However, until now, the systematic studies on the halovirus ecology and the effects of salt concentration on virus-host systems are lacking.Our results also demonstrated that cells incubated at a high salt concentration prior to infection increased the ability of the virus to adsorb and lyse its host cells; therefore, the physiological status of host cells also affected the virus-host interaction.In conclusion, SNJ1 acted as a predator, lysing host cells and releasing progeny viruses in hypersaline environments; in low salt environments, viruses lysogenized host cells to escape the damage from low salinity.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan, Hubei, China.

ABSTRACT
Halovirus is a major force that affects the evolution of extreme halophiles and the biogeochemistry of hypersaline environments. However, until now, the systematic studies on the halovirus ecology and the effects of salt concentration on virus-host systems are lacking. To provide more valuable information for understanding ecological strategies of a virus-host system in the hypersaline ecosystem, we studied the interaction between halovirus SNJ1 and its host Natrinema sp.J7-2 under various NaCl concentrations. We found that the adsorption rate and lytic rate increased with salt concentration, demonstrating that a higher salt concentration promoted viral adsorption and proliferation. Contrary to the lytic rate, the lysogenic rate decreased as the salt concentration increased. Our results also demonstrated that cells incubated at a high salt concentration prior to infection increased the ability of the virus to adsorb and lyse its host cells; therefore, the physiological status of host cells also affected the virus-host interaction. In conclusion, SNJ1 acted as a predator, lysing host cells and releasing progeny viruses in hypersaline environments; in low salt environments, viruses lysogenized host cells to escape the damage from low salinity.

No MeSH data available.


Related in: MedlinePlus