In order to analyze the signaling function of hydrogen peroxide （H202） production in senescence in more detail, we manipulated intracellular H202 levels in Arabidopsis thaliala （L.） Heynh by using the hydrogen- pe...In order to analyze the signaling function of hydrogen peroxide （H202） production in senescence in more detail, we manipulated intracellular H202 levels in Arabidopsis thaliala （L.） Heynh by using the hydrogen- peroxide-sensitive part of the Escherichia coil transcription regulator OxyR, which was directed to the cytoplasm as well as into the peroxisomes. H202 levels were lowered and senescence was delayed in both transgenic lines, but OxyR was found to be more effective in the cytoplasm. To transfer this knowledge to crop plants, we analyzed oilseed rape plants Brassica napus L. cv. Mozart for H20~ and its scavenging enzymes catalase （CAT） and ascorbate peroxidase （APX） during leaf and plant development. H202 levels were found to increase during bolting and flowering time, but no increase could be observed in the very late stages of senescence. With increasing H202 levels, CAT and APX activities declined, so it is likely that similar mechanisms are used in oilseed rape and Arabidopsis to control H202 levels. Under elevated CO2 conditions, oilseed rape senescence was accelerated and coincided with an earlier increase in H202 levels, indicating that H202 may be one of the signals to inducing senescence in a broader range of Brassicaceae.展开更多
Inflammatory,proliferative and remodeling phases constitute a cutaneous wound healing program.Therapeutic applications and medication are available;however,they commonly are comprised of fortified preservatives that m...Inflammatory,proliferative and remodeling phases constitute a cutaneous wound healing program.Therapeutic applications and medication are available;however,they commonly are comprised of fortified preservatives that might prolong the healing process.Chick early amniotic fluids(ceAF)contain native therapeutic factors with balanced chemokines,cytokines and growth-related factors;their origins in principle dictate no existence of harmful agents that would otherwise hamper embryo development.Instead,they possess a spectrum of molecules driving expeditious mitotic divisions and possibly exerting other functions.Employing both in vitro and in vivo models,we examined ceAF's therapeutic potentials in wound healing and found intriguing involvement of transient senescence,known to be intimately intermingled with Senescence Associated Secretory Phenotypes(SASP)that function in addition to or in conjunction with ceAF to facilitate wound healing.In our cutaneous wound healing models,a low dose of ceAF exhibited the best efficacies;however,higher doses attenuated the wound healing presumably by inducing p16 expression over a threshold.Our studies thus link an INK4/ARF locus-mediated signaling cascade to cutaneous wound healing,suggesting therapeutic potentials of ceAF exerting functions likely by driving transient senescence,expediting cellular proliferation,migration,and describing a homeostatic and balanced dosage strategy in medical intervention.展开更多
文摘In order to analyze the signaling function of hydrogen peroxide （H202） production in senescence in more detail, we manipulated intracellular H202 levels in Arabidopsis thaliala （L.） Heynh by using the hydrogen- peroxide-sensitive part of the Escherichia coil transcription regulator OxyR, which was directed to the cytoplasm as well as into the peroxisomes. H202 levels were lowered and senescence was delayed in both transgenic lines, but OxyR was found to be more effective in the cytoplasm. To transfer this knowledge to crop plants, we analyzed oilseed rape plants Brassica napus L. cv. Mozart for H20~ and its scavenging enzymes catalase （CAT） and ascorbate peroxidase （APX） during leaf and plant development. H202 levels were found to increase during bolting and flowering time, but no increase could be observed in the very late stages of senescence. With increasing H202 levels, CAT and APX activities declined, so it is likely that similar mechanisms are used in oilseed rape and Arabidopsis to control H202 levels. Under elevated CO2 conditions, oilseed rape senescence was accelerated and coincided with an earlier increase in H202 levels, indicating that H202 may be one of the signals to inducing senescence in a broader range of Brassicaceae.
文摘Inflammatory,proliferative and remodeling phases constitute a cutaneous wound healing program.Therapeutic applications and medication are available;however,they commonly are comprised of fortified preservatives that might prolong the healing process.Chick early amniotic fluids(ceAF)contain native therapeutic factors with balanced chemokines,cytokines and growth-related factors;their origins in principle dictate no existence of harmful agents that would otherwise hamper embryo development.Instead,they possess a spectrum of molecules driving expeditious mitotic divisions and possibly exerting other functions.Employing both in vitro and in vivo models,we examined ceAF's therapeutic potentials in wound healing and found intriguing involvement of transient senescence,known to be intimately intermingled with Senescence Associated Secretory Phenotypes(SASP)that function in addition to or in conjunction with ceAF to facilitate wound healing.In our cutaneous wound healing models,a low dose of ceAF exhibited the best efficacies;however,higher doses attenuated the wound healing presumably by inducing p16 expression over a threshold.Our studies thus link an INK4/ARF locus-mediated signaling cascade to cutaneous wound healing,suggesting therapeutic potentials of ceAF exerting functions likely by driving transient senescence,expediting cellular proliferation,migration,and describing a homeostatic and balanced dosage strategy in medical intervention.
