The differences of glucose-6P dehydrogenase (G6PDH) activity and freezing resistance induced by freezing acclimation between cuttings of freezing-sensitive P. tomentosa and freezing-resistant P. suaveolens were compar...The differences of glucose-6P dehydrogenase (G6PDH) activity and freezing resistance induced by freezing acclimation between cuttings of freezing-sensitive P. tomentosa and freezing-resistant P. suaveolens were compared for exploring the role of G6PDH on the enhancement of freezing resistance induced by freezing acclimation. After 5 d of freezing acclimation at -3 ℃, the LT50 of P. tomentosa has decreased from -6.2 ℃ in control cuttings to -14.3 ℃ in freezing acclimated ones, and the increase of G6PDH activity was observed in freezing acclimated cuttings as compared with control ones. Whereas, when P. suaveolens was freezing acclimated at -20℃ for 5 d, the LT50 has decreased from -27.1℃ in control cuttings to -43.5 ℃ in freezing acclimated ones, and the activity of G6PDH increased considerably. In addition, the increase of LT50 and the decrease of G6PDH activity resulting from 2 d of deacclimation at 25 ℃ were found in two kinds of freezing acclimated cuttings. It is concluded that the increase in the activity of G6PDH may associate with the inherited freezing resistance of species and the enhancement of freezing resistance of cuttings, and may play an important role in the antifreeze process under freezing temperature, which would provide the basis for the study on the molecular mechanism of freezing resistance in P. suaveolens and the cloning of gene associated with freezing resistance.展开更多
Alternative treatment for the highly prevalent Helicobacter pylori infection is imperative due to rising antibiotic resistance.We unexpectedly discovered that the anti-H.pylori component in garlic is hydrogen polysulf...Alternative treatment for the highly prevalent Helicobacter pylori infection is imperative due to rising antibiotic resistance.We unexpectedly discovered that the anti-H.pylori component in garlic is hydrogen polysulfide(H_(2)S_(n),n≥2),not organic polysulfides.Studies on the mechanism of action(MoA)show that H2S_n specifically inactivates H.pylori glucose-6-phosphate dehydrogenase(G6PDH)by interfering with electron transfer from glucose-6-phosphate(G6P)to nicotinamide adenine dinucleotide phosphate(NADP+).However,low H_(2)S_(n)yield makes garlic derivatives hard to be a reliable donor of H_(2)S_(n)to treat H.pylori infection.To address this challenge,we established a polysulfide transformation process from garlic organosulfur compounds into Fe3S4that generates H_(2)S_(n)with a 25–58 times increase in yield.Through chitosan encapsulation,we designed a gastric-adaptive H_(2)S_(n)microreactor(GAPSR)that eradicates H.pylori with 250 times higher efficiency under gastric conditions.A single GAPSR achieves more rapid H.pylori eradication than combined antibiotics therapy without disturbing the gut microbiota.These findings indicate a distinct MoA transformation mediated by polysulfide as an alternative candidate to treat H.pylori infection.展开更多
基金National Natural Science Foundation of China(Grant No.30271093)
文摘The differences of glucose-6P dehydrogenase (G6PDH) activity and freezing resistance induced by freezing acclimation between cuttings of freezing-sensitive P. tomentosa and freezing-resistant P. suaveolens were compared for exploring the role of G6PDH on the enhancement of freezing resistance induced by freezing acclimation. After 5 d of freezing acclimation at -3 ℃, the LT50 of P. tomentosa has decreased from -6.2 ℃ in control cuttings to -14.3 ℃ in freezing acclimated ones, and the increase of G6PDH activity was observed in freezing acclimated cuttings as compared with control ones. Whereas, when P. suaveolens was freezing acclimated at -20℃ for 5 d, the LT50 has decreased from -27.1℃ in control cuttings to -43.5 ℃ in freezing acclimated ones, and the activity of G6PDH increased considerably. In addition, the increase of LT50 and the decrease of G6PDH activity resulting from 2 d of deacclimation at 25 ℃ were found in two kinds of freezing acclimated cuttings. It is concluded that the increase in the activity of G6PDH may associate with the inherited freezing resistance of species and the enhancement of freezing resistance of cuttings, and may play an important role in the antifreeze process under freezing temperature, which would provide the basis for the study on the molecular mechanism of freezing resistance in P. suaveolens and the cloning of gene associated with freezing resistance.
基金supported by the National Key R&D Program of China(2019YFA0709200)the National Natural Science Foundation of China(22121003,81930050)。
文摘Alternative treatment for the highly prevalent Helicobacter pylori infection is imperative due to rising antibiotic resistance.We unexpectedly discovered that the anti-H.pylori component in garlic is hydrogen polysulfide(H_(2)S_(n),n≥2),not organic polysulfides.Studies on the mechanism of action(MoA)show that H2S_n specifically inactivates H.pylori glucose-6-phosphate dehydrogenase(G6PDH)by interfering with electron transfer from glucose-6-phosphate(G6P)to nicotinamide adenine dinucleotide phosphate(NADP+).However,low H_(2)S_(n)yield makes garlic derivatives hard to be a reliable donor of H_(2)S_(n)to treat H.pylori infection.To address this challenge,we established a polysulfide transformation process from garlic organosulfur compounds into Fe3S4that generates H_(2)S_(n)with a 25–58 times increase in yield.Through chitosan encapsulation,we designed a gastric-adaptive H_(2)S_(n)microreactor(GAPSR)that eradicates H.pylori with 250 times higher efficiency under gastric conditions.A single GAPSR achieves more rapid H.pylori eradication than combined antibiotics therapy without disturbing the gut microbiota.These findings indicate a distinct MoA transformation mediated by polysulfide as an alternative candidate to treat H.pylori infection.
