In this study,to clarify the bioactive polypeptides included in the skins and secretions of Bufo,we screened the Japanese toad(Bufo japonicus formosus) skin cDNA library by colony polymerase chain reaction(PCR),and ob...In this study,to clarify the bioactive polypeptides included in the skins and secretions of Bufo,we screened the Japanese toad(Bufo japonicus formosus) skin cDNA library by colony polymerase chain reaction(PCR),and obtained a transcript of 1 075 bp consisting of 1 37 bp 5′ untranslated region(UTR),515 bp 3′ UTR and a 423 bp open reading frame(ORF) encoding a polypeptide of 140 amino acid residues(GenBank accession number: KF359945).Homolog analysis showed a 70%–96% homology with sterol carrier protein-2(SCP-2) present in other animals,which is implicated in lipid metabolism of other organisms.The gene SCP-2 of Chinese toad(B.gargarizans) was cloned from a first strand cDNA of Bufo skin(GenBank accession number: KF381341) via PCR,whose encoding polypeptide has only one amino acid difference from that of Japanese toad.Tissue distribution analysis showed that SCP-2 expressed in all organs tested,though in the liver and spleen it manifested lower expression than in other organs.These findings might indicate SCP-2 being one of the active ingredients in toad skin.These findings may in turn have implications for further drug development from traditional Chinese medicine sources.展开更多
Xenopus ZFP36L1 （zinc finger protein 36, C3H type-like 1） belongs to the ZFP36 family of RNA-binding proteins, which contains two characteristic tandem CCCH-type zinc-finger domains. The ZFP36 proteins can bind AU-r...Xenopus ZFP36L1 （zinc finger protein 36, C3H type-like 1） belongs to the ZFP36 family of RNA-binding proteins, which contains two characteristic tandem CCCH-type zinc-finger domains. The ZFP36 proteins can bind AU-rich elements in 3＇ untranslated regions of target mRNAs and promote their turnover. However, the expression and role of ZFP36 genes during neural development in Xenopus embryos remains largely unknown. The present study showed that Xenopus ZFP36L1 was expressed at the dorsal part of the forebrain, forebrain-midbrain boundary, and midbrain-hindbrain boundary from late neurula stages to tadpole stages of embryonic development. Overexpression of XZFP36L1 in Xenopus embryos inhibited neural induction and differentiation, leading to severe neural tube defects. The function of XZP36L1 requires both its zinc finger and C terminal domains, which also affect its subcellular localization. These results suggest that XZFP36L1 is likely involved in neural development in Xenopus and might play an important role in post-transcriptional regulation.展开更多
Anti-keratin monoclonal antibody AF5 was introduced into fertilized eggs of Xenopus laevis., and its effects on embryonic development were studied. Survival rate of the antikeratin-injected embryos was much lower (onl...Anti-keratin monoclonal antibody AF5 was introduced into fertilized eggs of Xenopus laevis., and its effects on embryonic development were studied. Survival rate of the antikeratin-injected embryos was much lower (only 35.76% at gastrula) than that of the control (74.85% at gastrula), in which embryos were injected with mouse IgG. Most of survivors in the experimental series showed aberrant external appearance. On the other hand, in cleavage stage, ie 2-7 h after fertilization, immunohistochemi-cal staining of embryos showed that the experimental embryos were mostly keratin negative, while embryos of the control ones were keratin positive. When introducing this antikeratin into one cell of a 2-cell embryo, only the unin-jected half of the embryo continued its development while the other half could not develop at all. These results suggested that intact keratin cytoskeleton in early embryos is indispensable to the embryonic development of Xenopus laevis.展开更多
AIM： To investigate the mechanism of bombesin-induced circular smooth muscle cell contraction in cat esophagus. METHODS： Specific G protein or phospholipase C involved in cat esophagus contraction was identified, mu...AIM： To investigate the mechanism of bombesin-induced circular smooth muscle cell contraction in cat esophagus. METHODS： Specific G protein or phospholipase C involved in cat esophagus contraction was identified, muscle cells were permeabilized with saponin. After per- meabilization of muscle cells, the Gi3 antibody inhibited bombesin-induced smooth muscle cell contraction. RESULTS： Incubation of permeabilized circular muscle cells with PLC-β3 antibody could inhibit bombesin-induced contraction. H-7, chelerythrine （PKC inhibitor） and genistein （protein tyrosine kinase inhibitor） inhibited bombesin-induced contraction, but DAG kinase inhibitor, R59949, could not inhibit it. To examine which mitogen-activated protein kinase （MAPK） was involved in bombesin-induced contTaction, the specific MAPK inhibitors （MEK inhibitor, PD98059 and p38 MAPK inhibitor, SB202190） were used. Preincubation of PD98059 blocked the contraction induced by bombesin in a concentration-dependent manner. However, SB202190 had no effects on contraction. CONCLUSION： Bombesin-induced circular muscle cell contraction in cat esophagus is mediated via a PKC or a PTK-dependent pathway or p44/p42 HAPK pathway.展开更多
OBJECTIVE: To probe insights into the reversal effect of bufalin on vincristine-acquired multidrug resistance(MDR) in human leukemia cell line K562/VCR.METHODS: Proliferative inhibition rate and the reversal index(RI)...OBJECTIVE: To probe insights into the reversal effect of bufalin on vincristine-acquired multidrug resistance(MDR) in human leukemia cell line K562/VCR.METHODS: Proliferative inhibition rate and the reversal index(RI) of bufalin were determined by Methyl thiazolyl tetrazolium assay. The uptake of Adriamycin(ADM) in K562/VCR cells, cell cycle and apoptosis rate were determined by flow cytometry(FCM). Cell morphologic changes were observed with Wright-Giemsa staining. The expression of P-glycoprotein(P-gp), multidrug-associated protein-1(MRP1), Bcl-x L and Bax protein were measured by immunocytochemistry.RESULTS: The human leukemia multidrug resistant K562/VCR cells showed no cross-resistance to bufalin. The RIs of bufalin at concentrations of 0.0002,0.001 and 0.005 μmol/L were 4.85, 6.94 and 14.77,respectively. Preincubation of 0.001 μmol/L bufalin for 2 h could increase intracellular ADM fluorescence intensity to 28.07%(P<0.05) and down-regulate MRP1 expression simultaneously, but no remarkable effect was found on P-gp protein. Cell cycle analysis indicated increased apoptosis rate and apparent decreased G2/M phase proportion after treatment with bufalin. When exposed to 0.01μmol/L bufalin, typical morphological changes of apoptosis could be observed. Down-regulation of Bcl-x L and up-regulation of Bax expression in K562/VCR cells could be detected by immunocytochemistry.CONCLUSION: Bufalin could partly reverse the MDR of K562/VCR cells, with a possible mechanism of down-regulating MRP1 expression and activating apoptosis pathway by altering Bcl-x L/Bax ratio.展开更多
基金Foundation items： This study was supported by the National Natural Science Foundation of China （31071181, 31372149） and the Students＇ Innovative Training Program of ZAFU （20120207, 20120213）
文摘In this study,to clarify the bioactive polypeptides included in the skins and secretions of Bufo,we screened the Japanese toad(Bufo japonicus formosus) skin cDNA library by colony polymerase chain reaction(PCR),and obtained a transcript of 1 075 bp consisting of 1 37 bp 5′ untranslated region(UTR),515 bp 3′ UTR and a 423 bp open reading frame(ORF) encoding a polypeptide of 140 amino acid residues(GenBank accession number: KF359945).Homolog analysis showed a 70%–96% homology with sterol carrier protein-2(SCP-2) present in other animals,which is implicated in lipid metabolism of other organisms.The gene SCP-2 of Chinese toad(B.gargarizans) was cloned from a first strand cDNA of Bufo skin(GenBank accession number: KF381341) via PCR,whose encoding polypeptide has only one amino acid difference from that of Japanese toad.Tissue distribution analysis showed that SCP-2 expressed in all organs tested,though in the liver and spleen it manifested lower expression than in other organs.These findings might indicate SCP-2 being one of the active ingredients in toad skin.These findings may in turn have implications for further drug development from traditional Chinese medicine sources.
基金Foundation items： This work was supported by National Natural Science Foundation of China （90919039 C120106） Acknowledgements We thank the National Institute for Basic Biology, Japan, for the X1073h24 clone.
文摘Xenopus ZFP36L1 （zinc finger protein 36, C3H type-like 1） belongs to the ZFP36 family of RNA-binding proteins, which contains two characteristic tandem CCCH-type zinc-finger domains. The ZFP36 proteins can bind AU-rich elements in 3＇ untranslated regions of target mRNAs and promote their turnover. However, the expression and role of ZFP36 genes during neural development in Xenopus embryos remains largely unknown. The present study showed that Xenopus ZFP36L1 was expressed at the dorsal part of the forebrain, forebrain-midbrain boundary, and midbrain-hindbrain boundary from late neurula stages to tadpole stages of embryonic development. Overexpression of XZFP36L1 in Xenopus embryos inhibited neural induction and differentiation, leading to severe neural tube defects. The function of XZP36L1 requires both its zinc finger and C terminal domains, which also affect its subcellular localization. These results suggest that XZFP36L1 is likely involved in neural development in Xenopus and might play an important role in post-transcriptional regulation.
文摘Anti-keratin monoclonal antibody AF5 was introduced into fertilized eggs of Xenopus laevis., and its effects on embryonic development were studied. Survival rate of the antikeratin-injected embryos was much lower (only 35.76% at gastrula) than that of the control (74.85% at gastrula), in which embryos were injected with mouse IgG. Most of survivors in the experimental series showed aberrant external appearance. On the other hand, in cleavage stage, ie 2-7 h after fertilization, immunohistochemi-cal staining of embryos showed that the experimental embryos were mostly keratin negative, while embryos of the control ones were keratin positive. When introducing this antikeratin into one cell of a 2-cell embryo, only the unin-jected half of the embryo continued its development while the other half could not develop at all. These results suggested that intact keratin cytoskeleton in early embryos is indispensable to the embryonic development of Xenopus laevis.
文摘AIM： To investigate the mechanism of bombesin-induced circular smooth muscle cell contraction in cat esophagus. METHODS： Specific G protein or phospholipase C involved in cat esophagus contraction was identified, muscle cells were permeabilized with saponin. After per- meabilization of muscle cells, the Gi3 antibody inhibited bombesin-induced smooth muscle cell contraction. RESULTS： Incubation of permeabilized circular muscle cells with PLC-β3 antibody could inhibit bombesin-induced contraction. H-7, chelerythrine （PKC inhibitor） and genistein （protein tyrosine kinase inhibitor） inhibited bombesin-induced contraction, but DAG kinase inhibitor, R59949, could not inhibit it. To examine which mitogen-activated protein kinase （MAPK） was involved in bombesin-induced contTaction, the specific MAPK inhibitors （MEK inhibitor, PD98059 and p38 MAPK inhibitor, SB202190） were used. Preincubation of PD98059 blocked the contraction induced by bombesin in a concentration-dependent manner. However, SB202190 had no effects on contraction. CONCLUSION： Bombesin-induced circular muscle cell contraction in cat esophagus is mediated via a PKC or a PTK-dependent pathway or p44/p42 HAPK pathway.
基金Shanghai Municipal Health Bureau:Traditional Chinese Medicine in Treating with Advanced Hepatocellular Carcinoma(No.ZYSNXD-CC-ZDYJ032)
文摘OBJECTIVE: To probe insights into the reversal effect of bufalin on vincristine-acquired multidrug resistance(MDR) in human leukemia cell line K562/VCR.METHODS: Proliferative inhibition rate and the reversal index(RI) of bufalin were determined by Methyl thiazolyl tetrazolium assay. The uptake of Adriamycin(ADM) in K562/VCR cells, cell cycle and apoptosis rate were determined by flow cytometry(FCM). Cell morphologic changes were observed with Wright-Giemsa staining. The expression of P-glycoprotein(P-gp), multidrug-associated protein-1(MRP1), Bcl-x L and Bax protein were measured by immunocytochemistry.RESULTS: The human leukemia multidrug resistant K562/VCR cells showed no cross-resistance to bufalin. The RIs of bufalin at concentrations of 0.0002,0.001 and 0.005 μmol/L were 4.85, 6.94 and 14.77,respectively. Preincubation of 0.001 μmol/L bufalin for 2 h could increase intracellular ADM fluorescence intensity to 28.07%(P<0.05) and down-regulate MRP1 expression simultaneously, but no remarkable effect was found on P-gp protein. Cell cycle analysis indicated increased apoptosis rate and apparent decreased G2/M phase proportion after treatment with bufalin. When exposed to 0.01μmol/L bufalin, typical morphological changes of apoptosis could be observed. Down-regulation of Bcl-x L and up-regulation of Bax expression in K562/VCR cells could be detected by immunocytochemistry.CONCLUSION: Bufalin could partly reverse the MDR of K562/VCR cells, with a possible mechanism of down-regulating MRP1 expression and activating apoptosis pathway by altering Bcl-x L/Bax ratio.
