AIM: To investigate whether hypoxia inducible factor-1α (HIF-1α) is linked to the protective effects of ischemic preconditioning (IP) on sinusoidal endothelial cells against ischemia/reperfusion injury. METHODS: Sin...AIM: To investigate whether hypoxia inducible factor-1α (HIF-1α) is linked to the protective effects of ischemic preconditioning (IP) on sinusoidal endothelial cells against ischemia/reperfusion injury. METHODS: Sinusoidal endothelial cell lines ECV-304 were cultured and divided into four groups: control group, cells were cultured in complete DMEM medium; cold anoxia/warm reoxygenation (A/R) group, cells were preserved in a 4℃ UW solution in a mixture of 95% N2 and 5% CO2 for 24 h; anoxia-preconditioning (APC) group, cells were treated with 4 cycles of short anoxia and reoxygenation before prolonged anoxia- preconditioning treatment; and anoxia-preconditioning and hypoxia inducible factor-1α (HIF-1α) inhibitor (I-HIF-1) group, cells were pretreated with 5 μm of HIF-1α inhibitor NS398 in DMEM medium before subjected to the same treatment as group APC. After the anoxia treatment, each group was reoxygenated in a mixture of 95% air and 5% CO2 incubator for 6 h. Cytoprotections were evaluated by cell viabilities from Trypan blue, lactate dehydrogenase (LDH) release rates, and intracellular cell adhesion molecule-1 (ICAM-1) expressions. Expressions of HIF-1α mRNA and HIF-1α protein from each group were determined by the RT-PCR method and Western blotting, respectively. RESULTS: Ischemia preconditioning increased cell viability, and reduced LDH release and ICAM-1 expressions. Ischemia preconditioning also upregulated the HIF-1α mRNA level and HIF-1α protein expression. However, all of these changes were reversed by HIF-1α inhibitor NS398.CONCLUSION: Ischemia preconditioning effectively inhibited cold hypoxia/warm reoxygenation injury to endothelial cells, and the authors showed for the first time HIF-1α is causally linked to the protective effects of ischemic preconditioning on endothelial cells.展开更多
The shape of unperturbed polymer chains was studied using the Monte Carlo technique on a tetrahedral lattice.The asphericity A, the ratios【L<sub>2</sub><sup>2</sup>】/【L<sub>1</sub&g...The shape of unperturbed polymer chains was studied using the Monte Carlo technique on a tetrahedral lattice.The asphericity A, the ratios【L<sub>2</sub><sup>2</sup>】/【L<sub>1</sub><sup>2</sup>】and【L<sub>3</sub><sup>2</sup>】/【L<sub>1</sub><sup>2</sup>】 were calculated for different values of polymer chain length n,conformational energy ε （ε≥0） and temperature T. The asphericity A decreases with the increase of chain length and tends toreach its limiting value rapidly with the decrease of γ（γ=ε/k<sub>B</sub>T）. For large n, A is about 0.525±0.005, the ratios【L<sub>2</sub><sup>2</sup>】/【L<sub>1</sub><sup>2</sup>】 and【L<sub>3</sub><sup>2</sup>】/【L<sub>1</sub><sup>2</sup>】 are about 2.7 and 12.0, respectively, and are almost independent of γ, but for short chains, theydepend on γ.展开更多
The conformational entropy S and free energy F were calculated by exact enumeration of polysilane chain up to 23 segments with excluded volume (EV) and long-range van der Waals (VW) interaction. A nonlinear relation b...The conformational entropy S and free energy F were calculated by exact enumeration of polysilane chain up to 23 segments with excluded volume (EV) and long-range van der Waals (VW) interaction. A nonlinear relation between SEV+VW and chain length n was found though SEV was found to vary linearly with n. We found that the second-order transition temperature of polysilane chain with VW interaction increases with the increase of chain length, while that of polysilane chain without VW interaction is chain length independent. Moreover, the free energies FEV+VW and FEV are both linearly related with n, and FEV+VW＜FEV for all temperatures.展开更多
Malaria is 1 mosquito-borne disease,which is most commonly caused by a parasite called Plasmodium falciparum(P.falciparum).Cerebral malaria is the most severe neurological complication presented in
This paper deals with the existence of travelling wave fronts of delayed reaction diffusion systemswith partial quasi-monotonicity.We propose a concept of'desirable pair of upper-lower solutions',throughwhich ...This paper deals with the existence of travelling wave fronts of delayed reaction diffusion systemswith partial quasi-monotonicity.We propose a concept of'desirable pair of upper-lower solutions',throughwhich a subset can be constructed.We then apply the Schauder's fixed point theorem to some appropriateoperator in this subset to obtain the existence of the travelling wave fronts.展开更多
Odorant-binding proteins(OBPs)are crucial in insect's olfactory perception,which participate in the initial step of odorant molecules transporting from the external environment to olfactory receptor neurons.To bet...Odorant-binding proteins(OBPs)are crucial in insect's olfactory perception,which participate in the initial step of odorant molecules transporting from the external environment to olfactory receptor neurons.To better understand the roles for OBPs in olfactory perception in Cotesia vestalis,a solitary larval endoparasitoid of diamondback moth,Plutella xylostella,we have comprehensively screened the genome of C.vestalis,and obtained 20 CvesOBPs,including 18 classic OBPs and two minus-C OBPs.Motif-pattern analysis indicates that the motifs of C.vestalis OBPs are highly conserved in Hymenoptera.The results of tissue expression analysis show that five OBPs(CvesOBP1/11/12/14/16)are highly expressed in male antennae,whereas six other OBP genes(CvesOBP7/8/13/17/18/19)are significantly transcriptionally enriched in female antennae.The results of RNA interference experiments for three most highly expressed OBP genes(CvesOBP17/18/19)in female antennae demonstrate that they are likely involved in parasitic processes of female wasps,as the wasps take a longer time to target the hosts when they are knoc ked down.展开更多
The scaling relations among the mean end-to-end distance of polymer along the channel<R||>,the polymer length N,and the effective diameter of channel De were investigated for flexible and semi-flexible polymer c...The scaling relations among the mean end-to-end distance of polymer along the channel<R||>,the polymer length N,and the effective diameter of channel De were investigated for flexible and semi-flexible polymer chains confined in long cylindrical channels.For the flexible polymer chain,scaling relation<R||>~NDe–0.7 was found in the classic de Gennes regime at lp2/b<De<Rg with lp the persistence length,b the bond length,and Rg the radius of gyration of polymer.For the semi-flexible polymer,<R||>~NDe–1 in the transition regime lp<De<xlp(x>1)and<R|>~De–0.7 in the classic de Gennes regime at larger De>xlp were observed.The simulation results revealed that the scaling relation in the transition regime was due to the rod-like behavior of the semi-flexible polymer in the small regime lp<De<xlp.展开更多
Polydnaviruses(PDVs)are obligatory symbionts of parasitoid wasps and play an important role in suppressing host immune defenses.Although PDV genes that inhibit host melanization are known in Microplitis bracovirus,the...Polydnaviruses(PDVs)are obligatory symbionts of parasitoid wasps and play an important role in suppressing host immune defenses.Although PDV genes that inhibit host melanization are known in Microplitis bracovirus,the functional homologs in Cotesia bracoviruses remain unknown.Here,we find that Cotesia vestalis bracovirus(CvBV)can inhibit hemolymph melanization of its host,Plutella xylostella larvae,during the early stages of parasitization,and that overexpression of highly expressed CvBV genes reduced host phenoloxidase activity.Furthermore,CvBV-7-I in particular reduced host phenolox-idase activity within 12 h,and the injection of anti-CvBV-7-1 antibody increased the melanization of parasitized host larvae.Further analyses showed that CvBV-7-1 and three homologs from other Cotesia bracoviruses possessed a C-terminal leucine/isoleucine-rich region and had a similar flinction in inhibiting melanization.Therefore,a new family of bracovirus genes was proposed and named as C-terminal Leucine/isoleucine-rich Protein(CLP).Ectopic expression of CvBV-7-1 in Drosophila hemocytes increased susceptibility to bacterial repression of melanization and reduced the melanotic encapsulation of par-asitized D.melanogaster by the parasitoid Leptopilina boulardi.The formation rate of wasp pupae and the eclosion rate of C.vestalis were affected when the function of CvBV-7-1 was blocked.Our findings suggest that CLP genes from Cotesia bracoviruses encoded proteins that contain a C-terminal leucine/isoleucine-rich region and function as melanization inhibitors during the early stage of parasitization,which is important for successful parasitization.展开更多
文摘AIM: To investigate whether hypoxia inducible factor-1α (HIF-1α) is linked to the protective effects of ischemic preconditioning (IP) on sinusoidal endothelial cells against ischemia/reperfusion injury. METHODS: Sinusoidal endothelial cell lines ECV-304 were cultured and divided into four groups: control group, cells were cultured in complete DMEM medium; cold anoxia/warm reoxygenation (A/R) group, cells were preserved in a 4℃ UW solution in a mixture of 95% N2 and 5% CO2 for 24 h; anoxia-preconditioning (APC) group, cells were treated with 4 cycles of short anoxia and reoxygenation before prolonged anoxia- preconditioning treatment; and anoxia-preconditioning and hypoxia inducible factor-1α (HIF-1α) inhibitor (I-HIF-1) group, cells were pretreated with 5 μm of HIF-1α inhibitor NS398 in DMEM medium before subjected to the same treatment as group APC. After the anoxia treatment, each group was reoxygenated in a mixture of 95% air and 5% CO2 incubator for 6 h. Cytoprotections were evaluated by cell viabilities from Trypan blue, lactate dehydrogenase (LDH) release rates, and intracellular cell adhesion molecule-1 (ICAM-1) expressions. Expressions of HIF-1α mRNA and HIF-1α protein from each group were determined by the RT-PCR method and Western blotting, respectively. RESULTS: Ischemia preconditioning increased cell viability, and reduced LDH release and ICAM-1 expressions. Ischemia preconditioning also upregulated the HIF-1α mRNA level and HIF-1α protein expression. However, all of these changes were reversed by HIF-1α inhibitor NS398.CONCLUSION: Ischemia preconditioning effectively inhibited cold hypoxia/warm reoxygenation injury to endothelial cells, and the authors showed for the first time HIF-1α is causally linked to the protective effects of ischemic preconditioning on endothelial cells.
基金This work was supported by the National Natural Science Foundation of China (No. 29736170).
文摘The shape of unperturbed polymer chains was studied using the Monte Carlo technique on a tetrahedral lattice.The asphericity A, the ratios【L<sub>2</sub><sup>2</sup>】/【L<sub>1</sub><sup>2</sup>】and【L<sub>3</sub><sup>2</sup>】/【L<sub>1</sub><sup>2</sup>】 were calculated for different values of polymer chain length n,conformational energy ε （ε≥0） and temperature T. The asphericity A decreases with the increase of chain length and tends toreach its limiting value rapidly with the decrease of γ（γ=ε/k<sub>B</sub>T）. For large n, A is about 0.525±0.005, the ratios【L<sub>2</sub><sup>2</sup>】/【L<sub>1</sub><sup>2</sup>】 and【L<sub>3</sub><sup>2</sup>】/【L<sub>1</sub><sup>2</sup>】 are about 2.7 and 12.0, respectively, and are almost independent of γ, but for short chains, theydepend on γ.
文摘The conformational entropy S and free energy F were calculated by exact enumeration of polysilane chain up to 23 segments with excluded volume (EV) and long-range van der Waals (VW) interaction. A nonlinear relation between SEV+VW and chain length n was found though SEV was found to vary linearly with n. We found that the second-order transition temperature of polysilane chain with VW interaction increases with the increase of chain length, while that of polysilane chain without VW interaction is chain length independent. Moreover, the free energies FEV+VW and FEV are both linearly related with n, and FEV+VW＜FEV for all temperatures.
文摘Malaria is 1 mosquito-borne disease,which is most commonly caused by a parasite called Plasmodium falciparum(P.falciparum).Cerebral malaria is the most severe neurological complication presented in
基金Supported by the National Natural Science Foundation of China(No.19971032)the second author is supported by Natural Science Foundation of Canadaby a Petro Canada Young Innovator Award.
文摘This paper deals with the existence of travelling wave fronts of delayed reaction diffusion systemswith partial quasi-monotonicity.We propose a concept of'desirable pair of upper-lower solutions',throughwhich a subset can be constructed.We then apply the Schauder's fixed point theorem to some appropriateoperator in this subset to obtain the existence of the travelling wave fronts.
基金the National Science Foundation of China(31630060,31672079 and 31772522)the Zhejiang Provincial Natural Science Foundation of China(LR 18C140001).
文摘Odorant-binding proteins(OBPs)are crucial in insect's olfactory perception,which participate in the initial step of odorant molecules transporting from the external environment to olfactory receptor neurons.To better understand the roles for OBPs in olfactory perception in Cotesia vestalis,a solitary larval endoparasitoid of diamondback moth,Plutella xylostella,we have comprehensively screened the genome of C.vestalis,and obtained 20 CvesOBPs,including 18 classic OBPs and two minus-C OBPs.Motif-pattern analysis indicates that the motifs of C.vestalis OBPs are highly conserved in Hymenoptera.The results of tissue expression analysis show that five OBPs(CvesOBP1/11/12/14/16)are highly expressed in male antennae,whereas six other OBP genes(CvesOBP7/8/13/17/18/19)are significantly transcriptionally enriched in female antennae.The results of RNA interference experiments for three most highly expressed OBP genes(CvesOBP17/18/19)in female antennae demonstrate that they are likely involved in parasitic processes of female wasps,as the wasps take a longer time to target the hosts when they are knoc ked down.
基金financially supported by the National Natural Science Foundation of China (Nos. 21574117 and 11674277)Zhejiang Provincial Natural Science Foundation of China (No. LY16A040004)
文摘The scaling relations among the mean end-to-end distance of polymer along the channel<R||>,the polymer length N,and the effective diameter of channel De were investigated for flexible and semi-flexible polymer chains confined in long cylindrical channels.For the flexible polymer chain,scaling relation<R||>~NDe–0.7 was found in the classic de Gennes regime at lp2/b<De<Rg with lp the persistence length,b the bond length,and Rg the radius of gyration of polymer.For the semi-flexible polymer,<R||>~NDe–1 in the transition regime lp<De<xlp(x>1)and<R|>~De–0.7 in the classic de Gennes regime at larger De>xlp were observed.The simulation results revealed that the scaling relation in the transition regime was due to the rod-like behavior of the semi-flexible polymer in the small regime lp<De<xlp.
基金supported by the Key Program of National Natural Science Foundation of China(31630060)National Key Research and Development Program of China(2019YFD0300104)to XXC+5 种基金the National Key Research and Development Program of China(2017YFD0200400)the National Science Fund for Excellent Young Scholars(31622048)the National Science Foundation of China(31772522)to JHHthe National Science Foundation of China(31672079)Zhejiang Provincial Natural Science Foundation of China(LR18C140001)to MSthe National Science Foundation of China(31901942)to ZHW.
文摘Polydnaviruses(PDVs)are obligatory symbionts of parasitoid wasps and play an important role in suppressing host immune defenses.Although PDV genes that inhibit host melanization are known in Microplitis bracovirus,the functional homologs in Cotesia bracoviruses remain unknown.Here,we find that Cotesia vestalis bracovirus(CvBV)can inhibit hemolymph melanization of its host,Plutella xylostella larvae,during the early stages of parasitization,and that overexpression of highly expressed CvBV genes reduced host phenoloxidase activity.Furthermore,CvBV-7-I in particular reduced host phenolox-idase activity within 12 h,and the injection of anti-CvBV-7-1 antibody increased the melanization of parasitized host larvae.Further analyses showed that CvBV-7-1 and three homologs from other Cotesia bracoviruses possessed a C-terminal leucine/isoleucine-rich region and had a similar flinction in inhibiting melanization.Therefore,a new family of bracovirus genes was proposed and named as C-terminal Leucine/isoleucine-rich Protein(CLP).Ectopic expression of CvBV-7-1 in Drosophila hemocytes increased susceptibility to bacterial repression of melanization and reduced the melanotic encapsulation of par-asitized D.melanogaster by the parasitoid Leptopilina boulardi.The formation rate of wasp pupae and the eclosion rate of C.vestalis were affected when the function of CvBV-7-1 was blocked.Our findings suggest that CLP genes from Cotesia bracoviruses encoded proteins that contain a C-terminal leucine/isoleucine-rich region and function as melanization inhibitors during the early stage of parasitization,which is important for successful parasitization.
