During Nucleotide Excision Repair (NER) in the yeast S. cerevisiae, ubiquitylation of Rad4 is carried out by the E3 ubiquitin ligase that includes Rad7-Elc1-Cul3 and is critical to optimal NER. Rad7 E3 activity target...During Nucleotide Excision Repair (NER) in the yeast S. cerevisiae, ubiquitylation of Rad4 is carried out by the E3 ubiquitin ligase that includes Rad7-Elc1-Cul3 and is critical to optimal NER. Rad7 E3 activity targets Rad4 for degradation by the proteaseome but, in principle, could also trigger other DNA damage responses. We observed increased nuclear ubiquitin foci (Ub-RFP) formation in S. cerevisiae containing a Rad7 E3 ligase mutant (rad7SOCS) in response to DNA damage by benzo[a]pyrenediolepoxide (BPDE) in dividing cells. Immunoblots reveal that ubiquitin conjugates of Rpn10 and Dsk2 accumulate in greater abundance in rad7SOCS compared to RAD7 in dividing cells in response to BPDE which makes Rpn10 and Dsk2 candidates for being the ubiquitylated species observed in our microscopy experiments. Microscopy analysis with strains containing Dsk2-GFP shows that Dsk2-GFP and Dsk2-GFP/Ub-RFP colocalized in nuclear foci form to an increased extent in a rad7SOCS mutant background in dividing cells than in a RAD7 wild-type strain. Further, Dsk2-GFP in the rad7SOCS strain formed more foci at the plasma membrane following BPDE treatment in dividing cells relative to strains containing RAD7 or a rad7△?deletion mutant. In response to a different agent, UV irradiation, levels of ubiquitylated proteins were increased in rad7SOCS relative to RAD7, and the proteasomal deubiquitylase subunit, Rpn11 was even monoubiquitylated in the absence of damaging agents. Together these data show that Rad7 E3 activity attenuates ubiq-uitylation of proteins regulating the shuttling of polyubiquitylated proteins to the proteasome (Dsk2 and Rpn10) and removal of ubiquitin chains just prior to degradation (Rpn11). Since Rad7 E3 ligase activity has been shown to increase ubiquitylation of its target proteins, yet our results show increased ubiquitylation in the absence of Rad7 E3, we suggest that Rad7 E3 action regulates ubiquitin ligase and deubiquitylase (DUB) activities that act on Rpn10, Dsk2 and Rpn11.展开更多
Coconut water has several uses that are beneficial to humans, mainly because of its nutritional and medicinal properties. In this study coconut water samples were collected from the fresh mature coconuts and from pack...Coconut water has several uses that are beneficial to humans, mainly because of its nutritional and medicinal properties. In this study coconut water samples were collected from the fresh mature coconuts and from packaged processed coconut water to measure the radon concentrations in them. The results were used to estimate the annual effective radiation dose to the general adult population from ingestion of coconut water. The samples were analyzed for radon concentrations using the Durridge RAD-7 radon detector. The results of measured radon concentrations for the fresh mature coconut were ranged from 381.10 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span> to 1716.80 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span>. The results for packaged processed coconut samples ranged from 68.08 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span> to 556.85 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span>. The mean values for the samples were (1081.40 and 222.78) Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span> for the fresh and processed samples, respectively. The estimated mean annual effective doses (AED) due to ingestion of coconut water were 0.41 and 0.08 μSv·y<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-1</sup></span> for fresh and processed samples, respectively. These values are significantly lower than the safe limits recommended by the World Health Organization and the European Commission of 0.1 mSv·y<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-1</sup></span> and the maximum contamination level (MCL) of 11,000 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span> by the United States Environmental Protection Agency and so do not constitute a risk to consumers of coconut water.展开更多
Rn-222 is the most important source of natural radiation and is responsible for approximately half of the received dose from all sources. Most of this dose is from inhalation of the Rn-222 progeny, especially in close...Rn-222 is the most important source of natural radiation and is responsible for approximately half of the received dose from all sources. Most of this dose is from inhalation of the Rn-222 progeny, especially in closed ares. Portable alpha particle detector, RAD7 was used for Rn-222 measurements inside the main campus of Aljouf University at Saudi Arabia in order to estimate the effective dose to the occupants from 222Rn and its progeny. The values of annual effective doses for radon inhalation by the inhabitants were found to vary in the range 0.08 - 0.80 mSv/y, with a mean of 0.4 mSv/y. These results are lower than the value 1 mSv/y recommended by ICRP, 1990. The variation of dose relationship from indoor radon in lung tissue is calculated and tabulated. In addition to environmental value of the present survey, the results are considered to be essential in analyzing any data for future activities in this field.展开更多
文摘During Nucleotide Excision Repair (NER) in the yeast S. cerevisiae, ubiquitylation of Rad4 is carried out by the E3 ubiquitin ligase that includes Rad7-Elc1-Cul3 and is critical to optimal NER. Rad7 E3 activity targets Rad4 for degradation by the proteaseome but, in principle, could also trigger other DNA damage responses. We observed increased nuclear ubiquitin foci (Ub-RFP) formation in S. cerevisiae containing a Rad7 E3 ligase mutant (rad7SOCS) in response to DNA damage by benzo[a]pyrenediolepoxide (BPDE) in dividing cells. Immunoblots reveal that ubiquitin conjugates of Rpn10 and Dsk2 accumulate in greater abundance in rad7SOCS compared to RAD7 in dividing cells in response to BPDE which makes Rpn10 and Dsk2 candidates for being the ubiquitylated species observed in our microscopy experiments. Microscopy analysis with strains containing Dsk2-GFP shows that Dsk2-GFP and Dsk2-GFP/Ub-RFP colocalized in nuclear foci form to an increased extent in a rad7SOCS mutant background in dividing cells than in a RAD7 wild-type strain. Further, Dsk2-GFP in the rad7SOCS strain formed more foci at the plasma membrane following BPDE treatment in dividing cells relative to strains containing RAD7 or a rad7△?deletion mutant. In response to a different agent, UV irradiation, levels of ubiquitylated proteins were increased in rad7SOCS relative to RAD7, and the proteasomal deubiquitylase subunit, Rpn11 was even monoubiquitylated in the absence of damaging agents. Together these data show that Rad7 E3 activity attenuates ubiq-uitylation of proteins regulating the shuttling of polyubiquitylated proteins to the proteasome (Dsk2 and Rpn10) and removal of ubiquitin chains just prior to degradation (Rpn11). Since Rad7 E3 ligase activity has been shown to increase ubiquitylation of its target proteins, yet our results show increased ubiquitylation in the absence of Rad7 E3, we suggest that Rad7 E3 action regulates ubiquitin ligase and deubiquitylase (DUB) activities that act on Rpn10, Dsk2 and Rpn11.
文摘Coconut water has several uses that are beneficial to humans, mainly because of its nutritional and medicinal properties. In this study coconut water samples were collected from the fresh mature coconuts and from packaged processed coconut water to measure the radon concentrations in them. The results were used to estimate the annual effective radiation dose to the general adult population from ingestion of coconut water. The samples were analyzed for radon concentrations using the Durridge RAD-7 radon detector. The results of measured radon concentrations for the fresh mature coconut were ranged from 381.10 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span> to 1716.80 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span>. The results for packaged processed coconut samples ranged from 68.08 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span> to 556.85 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span>. The mean values for the samples were (1081.40 and 222.78) Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span> for the fresh and processed samples, respectively. The estimated mean annual effective doses (AED) due to ingestion of coconut water were 0.41 and 0.08 μSv·y<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-1</sup></span> for fresh and processed samples, respectively. These values are significantly lower than the safe limits recommended by the World Health Organization and the European Commission of 0.1 mSv·y<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-1</sup></span> and the maximum contamination level (MCL) of 11,000 Bq·m<span lang="EN-US" style="font-size:9pt;font-family:Tahoma, sans-serif;"><sup>-3</sup></span> by the United States Environmental Protection Agency and so do not constitute a risk to consumers of coconut water.
文摘Rn-222 is the most important source of natural radiation and is responsible for approximately half of the received dose from all sources. Most of this dose is from inhalation of the Rn-222 progeny, especially in closed ares. Portable alpha particle detector, RAD7 was used for Rn-222 measurements inside the main campus of Aljouf University at Saudi Arabia in order to estimate the effective dose to the occupants from 222Rn and its progeny. The values of annual effective doses for radon inhalation by the inhabitants were found to vary in the range 0.08 - 0.80 mSv/y, with a mean of 0.4 mSv/y. These results are lower than the value 1 mSv/y recommended by ICRP, 1990. The variation of dose relationship from indoor radon in lung tissue is calculated and tabulated. In addition to environmental value of the present survey, the results are considered to be essential in analyzing any data for future activities in this field.
