<span style="font-family:Verdana;"><i><span style="font-family:Verdana;"><i></span></i></span><span style="font-family:Verdana;"><span s...<span style="font-family:Verdana;"><i><span style="font-family:Verdana;"><i></span></i></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">S</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;"></i></span></i></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">-allyl-L-cysteine (SAC) is an organosulfur compound derived from aged garlic extract (</span><span style="font-family:Verdana;">AGE</span><span style="font-family:Verdana;">). Studies have reported that AGE possesses bioprotective capacity, including antidiabetic, antimicrobial, antioxidant, and antitumor effects. The present study examined the protective effects of SAC against carbon tetrachloride (CCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">) induced hepatotoxicity in rats. Ten male Wistar rats aged 11 - 12 weeks were randomly divided into two groups (five rats/group) as control and SAC groups. All rats had </span><span style="font-family:Verdana;">ad</span> <span style="font-family:Verdana;">libitum</span><span style="font-family:Verdana;"> access to water, and the SAC group received water containing SAC intragastrically (200 mg/kg) once daily for five consecutive weeks. In the fifth experimental week, 50% CCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> in olive oil (1 mL/kg) was administered intraperitoneally three times a week to induce liver injury in both groups. Rats were sacrificed at 24 hours after the last CCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> injection, and liver tissues were excised for histopathological, immunohistochemical and antioxidant analyses. The rats in the SAC group did not show abnormal behavior, such as decreased water intake or food consumption, during the experimental period. Body weights 展开更多
The abscisic acid （ABA） signaling pathway is regulated by clade A type 2C protein phosphatases （PP2CAs） in plants. In the presence of ABA, PP2Cs release stress/ABA-activated protein kinases by binding to ABA-bound...The abscisic acid （ABA） signaling pathway is regulated by clade A type 2C protein phosphatases （PP2CAs） in plants. In the presence of ABA, PP2Cs release stress/ABA-activated protein kinases by binding to ABA-bound receptors （PYL/RCARs） for activation. Although the wedging tryptophan in PP2Cs is critical in the interaction with PYL/RCARs in Arabidopsis and rice, it remains elusive as to how other interface regions are involved in the interaction. Here, we report the identification of a conserved region on PP2Cs, termed the VxG4ФL motif, which modulates the interaction with PYL/RCARs through its second and fourth residues. The effects of the second and fourth residues on the interaction of OsPP2CS0 with several OsPYIJRCAR proteins were investigated by systematic mutagenesis. One OsPP2C50 mutant, VFGML （＂FM＂） mutant, lowered the affinity to OsPYL/RCAR3 by Ф15-fold in comparison with the wUd-type. Compar- ison of the crystal structures of wild-type OsPP2C50：ABA：OsPYI./RCAR3 with those composed of FM mutant revealed local conformational changes near the VxGФL motif, further supported by hydrogen-deute- rium exchange mass spectrometry. In rice protoplasts, ABA signaling was altered by mutations in the VxGФL motif. Transgenic Arabidopsis plants overexpressing OsPP2C50 and OsPP2C5OFM showed altered ABA sensitivity. Taken together, the VxGФL motif of PP2Cs appears to modulate the affinity of PP2Cs with PYL/RCARs and thus likely to alter the ABA signaling, leading to the differential sensitivity to ABA in planta.展开更多
文摘<span style="font-family:Verdana;"><i><span style="font-family:Verdana;"><i></span></i></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;">S</span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;"></i></span></i></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">-allyl-L-cysteine (SAC) is an organosulfur compound derived from aged garlic extract (</span><span style="font-family:Verdana;">AGE</span><span style="font-family:Verdana;">). Studies have reported that AGE possesses bioprotective capacity, including antidiabetic, antimicrobial, antioxidant, and antitumor effects. The present study examined the protective effects of SAC against carbon tetrachloride (CCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">) induced hepatotoxicity in rats. Ten male Wistar rats aged 11 - 12 weeks were randomly divided into two groups (five rats/group) as control and SAC groups. All rats had </span><span style="font-family:Verdana;">ad</span> <span style="font-family:Verdana;">libitum</span><span style="font-family:Verdana;"> access to water, and the SAC group received water containing SAC intragastrically (200 mg/kg) once daily for five consecutive weeks. In the fifth experimental week, 50% CCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> in olive oil (1 mL/kg) was administered intraperitoneally three times a week to induce liver injury in both groups. Rats were sacrificed at 24 hours after the last CCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;"> injection, and liver tissues were excised for histopathological, immunohistochemical and antioxidant analyses. The rats in the SAC group did not show abnormal behavior, such as decreased water intake or food consumption, during the experimental period. Body weights
文摘The abscisic acid （ABA） signaling pathway is regulated by clade A type 2C protein phosphatases （PP2CAs） in plants. In the presence of ABA, PP2Cs release stress/ABA-activated protein kinases by binding to ABA-bound receptors （PYL/RCARs） for activation. Although the wedging tryptophan in PP2Cs is critical in the interaction with PYL/RCARs in Arabidopsis and rice, it remains elusive as to how other interface regions are involved in the interaction. Here, we report the identification of a conserved region on PP2Cs, termed the VxG4ФL motif, which modulates the interaction with PYL/RCARs through its second and fourth residues. The effects of the second and fourth residues on the interaction of OsPP2CS0 with several OsPYIJRCAR proteins were investigated by systematic mutagenesis. One OsPP2C50 mutant, VFGML （＂FM＂） mutant, lowered the affinity to OsPYL/RCAR3 by Ф15-fold in comparison with the wUd-type. Compar- ison of the crystal structures of wild-type OsPP2C50：ABA：OsPYI./RCAR3 with those composed of FM mutant revealed local conformational changes near the VxGФL motif, further supported by hydrogen-deute- rium exchange mass spectrometry. In rice protoplasts, ABA signaling was altered by mutations in the VxGФL motif. Transgenic Arabidopsis plants overexpressing OsPP2C50 and OsPP2C5OFM showed altered ABA sensitivity. Taken together, the VxGФL motif of PP2Cs appears to modulate the affinity of PP2Cs with PYL/RCARs and thus likely to alter the ABA signaling, leading to the differential sensitivity to ABA in planta.
