Vesicular stomatitis virus (VSV) was used as a model virus to study the processes involved in photoinactivation by aluminum phthalocyanine tetrasulfonate (AIPcS(4),) or silicon phthalocyanine HOSiPcOSi(CH3)(2)(CH2)(3)...
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Vesicular stomatitis virus (VSV) was used as a model virus to study the processes involved in photoinactivation by aluminum phthalocyanine tetrasulfonate (AIPcS(4),) or silicon phthalocyanine HOSiPcOSi(CH3)(2)(CH2)(3)N(CH3)(2) (Pc4) and red light. Previously a very rapid decrease in the intracellular viral RNA synthesis after photodynamic treatment was observed. This decrease was correlated to different steps in the replication cycle. Binding of VSV to host cells and internalization were only slightly impaired and could be visualized by electron microscopy. The capability of the virus to fuse with membranes in an acidic endosomal environment was studied using both pyrene-labeled liposomes and a hemolysis assay as a model. These tests indicate a rapid decrease of fusion capacity after AIPcS(4), treatment, which correlated with the decrease in RNA synthesis, For Pc4 treatment no such correlation was found. The fusion process is the first step in the replication cycle, affected by AIPcS(4) treatment, but also in vitro RNA polymerase activity was previously shown to be inhibited. Inactivation of VSV by Pc4 treatment is apparently caused by damage to a variety of viral components. Photodynamic treatment of virus suspensions with both sensitizers causes formation of 8-oxo-7,8-dihydroguanosine in viral RNA as measured by HPLC with electrochemical detection. This damage might be partly responsible for inhibition of the in vitro viral RNA polymerase activity by photodynamic treatment.
The effects of mouse interferon (IFN)-alpha/beta and recombinant IFN-gamma on mouse adenovirus type 1 (MAV-1) replication were investigated in single-cycle infectious virus yield reduction assays on mouse L929 cells. ...
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The effects of mouse interferon (IFN)-alpha/beta and recombinant IFN-gamma on mouse adenovirus type 1 (MAV-1) replication were investigated in single-cycle infectious virus yield reduction assays on mouse L929 cells. Viral yields at 3 days post-infection indicated that wt MAV-1 and pmE314, an early region 3 null mutant, were relatively insensitive to both IFN-alpha/beta and IFN-gamma, whereas early region 1A (E1A) mutants pmE109 (null), d/E105 (conserved region 1 deletion, CR1 Delta), d/E102 (CR2 Delta), and d/E106 (CR3 Delta) were sensitive. MAV-1 E1A that was inducibly expressed in mouse fibroblast 37.1 cells rescued vesicular stomatitis virus from the antiviral effect of IFN-alpha/beta but not from the antiviral effect of IFN-gamma. Interferon-inducible gene expression was reduced in 37.1 cells as compared to the parental 3T6 cell line. Steady-state levels of IFN-inducible gene mRNAs were also reduced in 3T6 cells infected with the wild-type virus and pmE314 but not in cells infected with pmE109. These results suggest that the MAV-1 E1A gene product is capable of interfering with the signaling pathways of both types of IFN, although modulation of IFN-alpha/beta antiviral activity was more pronounced. (C) 2000 Academic Press.
Merocyanine 540 (MC540)-mediated photodynamic damage to erythrocytes was strongly reduced when illumination was performed at pH 8.5 as compared to pH 7.4. This could be explained by high pa-mediated hyperpolarization ...
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Merocyanine 540 (MC540)-mediated photodynamic damage to erythrocytes was strongly reduced when illumination was performed at pH 8.5 as compared to pH 7.4. This could be explained by high pa-mediated hyperpolarization of the erythrocyte membrane, resulting in decreased MC540 binding at pH 8.5, In accordance, the MC540-mediated photooxidation of open ghosts was not inhibited at pH 8.5, Photoinactivation of vesicular stomatitis virus (VSV) was not inhibited at pH 8.5, This suggests that illumination at increased pH could be an approach to protect red blood cells selectively against MC540-mediated virucidal phototreatment, With tetrasulfonated aluminum phthalocyanine (AlPcS4) as photosensitizer, damage to erythrocytes, open ghosts and VSV was decreased when illuminated at pH 8.5. A decreased singlet oxygen yield at high pH could be excluded. The AlPcS4-mediated photooxidation of fixed erythrocytes was strongly dependent on the cation concentration in the buffer, indicating that the surface potential may affect the efficacy of this photosensitizer, This study showed that altering the environment of the target could increase both the efficacy and the specificity of a photodynamic treatment.
Photoinactivation of vesicular stomatitis virus (VSV) in stroma-free hemoglobin (SFH) was carried out using methylene blue (MB) or 19-dimethylmethylene blue (DMMB). The VSV was more sensitive to inactivation by 660 nn...
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Photoinactivation of vesicular stomatitis virus (VSV) in stroma-free hemoglobin (SFH) was carried out using methylene blue (MB) or 19-dimethylmethylene blue (DMMB). The VSV was more sensitive to inactivation by 660 nn light with 1 mu M DMMB than with the same concentration of MB. Under conditions that inactivated 6 log,, of VSV, the methemoglobin content (Met-Hb[%]) and P-50 of hemoglobin were changed by 1 mu M MB phototreatment but were not changed by 1 mu M DMMB phototreatment. The migration of hemoglobin during electophoresis and the activity of superoxide dismutase were? not changed by NIB or DMMB phototreatment. In contrast to the results obtained with DMME at 660 mm, 580 mm irradiation of SFH with DMMB resulted in a significant increase of Mel-Nb(%) under conditions that only inactivated 1.19 log(10) VSV. The 580 mn irradiation primarily activates the dimer and higher-order aggregates of the dyes, while 660 nm irradiation primarily activates the monomer, These results indicate that the monomer form of DMMB can effectively inactivate viruses without damage to SFH.
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