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1.
Nat Commun ; 15(1): 4742, 2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38834571

ABSTRACT

The further practical applications of Li-rich layered oxides are impeded by voltage decay and redox asymmetry, which are closely related to the structural degradation involving irreversible transition metal migration. It has been demonstrated that the superstructure ordering in O2-type materials can effectively suppress voltage decay and redox asymmetry. Herein, we elucidate that the absence of this superstructure ordering arrangement in a Ru-based O2-type oxide can still facilitate the highly reversible transition metal migration. We certify that Ru in superstructure-free O2-type structure can unlock a quite different migration path from Mn in mostly studied cases. The highly reversible migration of Ru helps the cathode maintain the structural robustness, thus realizing terrific capacity retention with neglectable voltage decay and inhibited oxygen redox asymmetry. We untie the knot that the absence of superstructure ordering fails to enable a high-performance Li-rich layered oxide cathode material with suppressed voltage decay and redox asymmetry.

2.
J Am Chem Soc ; 146(20): 13924-13933, 2024 May 22.
Article in English | MEDLINE | ID: mdl-38723613

ABSTRACT

O3-type layered oxides for sodium-ion batteries (SIBs) have attracted extensive attention due to their inherently sufficient Na content, which have been considered as one of the most promising candidates for practical applications. However, influenced by the irreversible oxygen loss and the phase transition of O3-P3, the O3-type cathodes are always limited by low cutoff voltages (typically <4.2 V), restraining the full release of the capacity. In this study, we originally propose a dual-reductive coupling mechanism in a novel O3-type Na0.8Li0.2Fe0.2Ru0.6O2 cathode with the suppressed O3-P3 phase transition, aiming at improving the reversibility of oxygen redox at high voltage regions. Consequently, thanks to the formation of the strong covalent Fe/Ru-(O-O) bonding and inhibited slab gliding from the O to P phase, the cathode delivers the preeminent cyclic stability among the numerous O3-type cathodes within a high voltage of 4.5 V (a capacity retention of 95.4% after 100 cycles within 1.5-4.5 V). More importantly, HAADF-STEM and 7Li solid-state NMR results reveal the absence of transition metal migration and the presence of reversible Li migration during cycling, which further contributes to the improved structural robustness of the cathode. This study proposes an innovative strategy to boost the reversibility of anionic redox and to achieve stable high-voltage O3-type layered oxides, promoting the further development of SIBs.

3.
Article in English | MEDLINE | ID: mdl-38615687

ABSTRACT

SETTING: Previous studies addressed the association between anti-thyroid antibodies and recurrent miscarriage (RM), however, the role of anti-thyroid antibodies in RM patients is debatable. OBJECTIVES: Therefore, we conducted this meta-analysis and the aim of this current study was to assess whether anti-thyroid peroxidase (anti-TPO) and/or anti-thyroglobulin (anti-TG) antibody positivity was associated with RM. DESIGN: A meta-analysis was conducted. PARTICIPANTS: Recurrent miscarriage patients. METHODS: STATA 12.0 software were applied to compute odds ratios (ORs)/relative risks (RRs) and 95% CIs regarding association between anti-TPO and anti-TG antibodies and the prevalence of RM. RESULTS: N = 28 studies (8875 participants) explored effect of anti-thyroid antibodies on RM. Analysis of the 28 studies revealed significant association between anti-TPO, anti-TG antibodies and the prevalence of RM with a random effects model (OR/RR = 2.02; 95% CI: 1.63-2.51, p < 0.001; I2 = 44.3%, p value for Q test = 0.004). Analysis of the 20 studies revealed significant association between anti-TPO antibodies and the prevalence of RM with a random effects model (OR/RR = 1.59; 95% CI: 1.25-2.03, p < 0.001; I2 = 43.1%, p value for Q test = 0.022). Analysis of the 14 studies revealed significant association between anti-TG antibodies and the prevalence of RM with a random effects model (OR/RR = 2.25; 95% CI: 1.56-3.23, p < 0.001; I2 = 49.2%, p value for Q test = 0.019). CONCLUSIONS: Based on the currently available analysis, our findings suggest that women with anti-TPO and/or anti-TG antibodies have a higher risk of RM than that in negative antibody women. Further investigation is needed to better clarify the exact role of the anti-thyroid antibodies in RM and whether treatment is of benefit. LIMITATIONS: First, differences from various detection methods and reagents used in different studies may affect the diagnostic interpretation of anti-thyroid antibodies, which might influence the accuracy of this meta-analysis. Second, positive anti-thyroid antibodies seem likely to be part of a more general disorder of maternal immune system, due to restrictions of funding and condition, a complete autoantibody screening investigation is hardly to conduct in all participants, and this could be a possible limitation of all included studies. Third, there is no mention of thyroxine therapy on RM, making the meta-analysis even more limited.

4.
J Nat Med ; 78(1): 42-52, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37698739

ABSTRACT

Ligustilide (LIG) is the main active ingredient of Angelica sinensis (Oliv.) Diels, which could promote focal angiogenesis to exert neuroprotection. However, there was no report that verified the exact effects of LIG on endometrial angiogenesis and the pregnancy outcomes. To explore the effects of LIG on low endometrial receptivity (LER) and angiogenesis, pregnancy rats were assigned into Control (saline treatment), LER (hydroxyurea-adrenaline treatment), LIG 20 mg/kg and LIG 40 mg/kg groups. Hematoxylin and eosin (H&E) staining was performed to evaluate endometrial morphology. Quantitative real-time PCR, immunofluorescence staining, western blot and immunohistochemistry staining were employed to assess the expression of endometrial receptivity factors and angiogenesis-related gene/protein, respectively. RNA sequencing was used to analyze the effects of LIG on LER caused by Kidney deficiency and blood stasis. We found that endometrial thickness and the implanted embryo number were substantially reduced in the hydroxyurea-adrenaline-treated pregnancy rats. At the same time, the gene and protein expressions of ERα, LIF, VEGFA and CD31 in the endometrium were markedly reduced, while the expressions of MUC1, E-cadherin were increased in the LER group. Administration of LIG raised the endometrial thickness and implanted embryos, as well as reversed the expressions of these factors. Collectively, our findings revealed that LIG could facilitate embryo implantation via recovery of the endometrium receptivity and promotion of endometrial angiogenesis.


Subject(s)
Hydroxyurea , Pregnancy Outcome , Pregnancy , Female , Rats , Animals , Hydroxyurea/metabolism , Hydroxyurea/pharmacology , Angiogenesis , Endometrium/metabolism , Epinephrine/metabolism , Epinephrine/pharmacology
5.
IBRO Neurosci Rep ; 15: 262-269, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37841087

ABSTRACT

Peripheral nerve injury is one of the more common forms of peripheral nerve disorders, and the most severe type of peripheral nerve injury is a defect with a gap. Biosynthetic cellulose membrane (BCM) is a commonly used material for repair and ligation of nerve defects with gaps. Meanwhile, exosomes from mesenchymal stem cells can promote cell growth and proliferation. We envision combining exosomes with BCMs to leverage the advantages of both to promote repair of peripheral nerve injury. Prepared exosomes were added to BCMs to form exosome-loaded BCMs (EXO-BCM) that were used for nerve repair in a rat model of sciatic nerve defects with gaps. We evaluated the repair activity using a pawprint experiment, measurement and statistical analyses of sciatica function index and thermal latency of paw withdrawal, and quantitation of the number and diameter of regenerated nerve fibers. Results indicated that EXO-BCM produced comprehensive and durable repair of peripheral nerve defects that were similar to those for autologous nerve transplantation, the gold standard for nerve defect repair. EXO-BCM is not predicted to cause donor site morbidity to the patient, in contrast to autologous nerve transplantation. Together these results indicate that an approach using EXO-BCM represents a promising alternative to autologous nerve transplantation, and could have broad applications for repair of nerve defects.

6.
Hum Exp Toxicol ; 42: 9603271231163476, 2023.
Article in English | MEDLINE | ID: mdl-37042322

ABSTRACT

BACKGROUND: Women with antiphospholipid syndrome (APS) or antiphospholipid antibodies (aPLs) are at high risk for obstetric complications, including recurrent pregnancy loss (RPL). However, effective treatments for RPL are lacking. OBJECTIVE: This study aimed to reveal the function and underlying mechanism of hyperoside (Hyp) in RPL associated with antiphospholipid antibodies (aCLs). METHODS: The pregnant rats (N = 24) were divided randomly into four groups: normal human-IgG (NH-IgG); aCL-pregnancy loss (aCL-PL); aCL-PL + Hyp (40 mg/kg/day); aCL-PL + low molecular weight heparin (LMWH, 525 µg/kg/day). HTR-8 cells were treated with 80 µg/mL aCL to establish the cell models of miscarriage. RESULTS: In pregnant rats, aCL-IgG injection raised the abortion rate of embryos, while Hyp treatment inhibited the effects. Additionally, Hyp inhibited the platelet activation and uteroplacental insufficiency caused by aCL. In vivo and in vitro experiments further suggested that Hyp suppressed aCL-induced inflammation and apoptosis by downregulating NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome-related factors and decreasing apoptotic rates. After aCL administration, Hyp therapy downregulated the expression of purinergic ligand-gated ion channel 7 (P2X7), which is reported to induce cytokine release and apoptosis. Furthermore, we found that the treatment of 3'-O-(4-Benzoyl) benzoyl-ATP (BzATP, an agonist of the P2X7 receptor) reversed the inhibitory effects of Hyp on cell function. CONCLUSIONS: Hyp exerts protective effects on aCL-induced pregnancy loss by preventing platelet activation-mediated P2X7/NLRP3 pathway. Therefore, Hyp may provide a feasible pharmaceutical strategy for the treatment of RPL.


Subject(s)
Abortion, Habitual , Antibodies, Anticardiolipin , Pregnancy , Female , Humans , Rats , Animals , Heparin, Low-Molecular-Weight , NLR Family, Pyrin Domain-Containing 3 Protein , Antibodies, Antiphospholipid , Abortion, Habitual/etiology , Abortion, Habitual/prevention & control , Immunoglobulin G
7.
J Ethnopharmacol ; 280: 114440, 2021 Nov 15.
Article in English | MEDLINE | ID: mdl-34293456

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: Wu-Zi-Yan-Zong-Wan (WZYZW) is a classical traditonal Chinese herbal formula and a Chinese patent medicine used to treat male infertility. However, the chemical components of WZYZW and its mechanism are not yet fully clarified. AIM OF THE STUDY: The purpose of this study is to observe the effect and underlying mechanism of WZYZW on ameliorating blood-testis barrier (BTB) dysfunction in mice with spermatogenic dysfunction induced by administration of Tripterygium wilfordii Hook. f. multiglycosides (GTW). MATERIALS AND METHODS: WZYZW was administered by gavage to mice with GTW-induced spermatogenic dysfunction (kidney essence deficiency pattern) for 40 days. Testis tissues were obtained for subsequent histopathological analysis. Biotin tracing was used to evaluate the permeability of Sertoli cell tight junctions. The levels of proinflammatory cytokines including interleukin (IL)-6, IL-17A, IL-1α and tumor necrosis factor (TNF)-α were analyzed by ELISA. The expression levels of proteins related to tight junction including ZO-1, JAM-A and occludin were analyzed by western blotting. The ultrastructures of tight junctions were observed by transmission electron microscopy. RESULTS: WZYZW ameliorated GTW-induced testicular spermatogenic dysfunction. Levels of IL-6, IL-17A, IL-1α, and TNF-α in the groups receiving low, medium, and high doses of WZYZW decreased in a dose-dependent manner. WZYZW impeded a biotin tracer from permeating the BTB, protecting its integrity in GTW-treated mice. In addition, our results showed no significant changes in the protein expressions of ZO-1, JAM-A, and occludin after WZYZW administration compared with the GTW group. Meanwhile, WZYZW exhibited a linear arrangement and restored the typical "sandwich" structure of BTB. No acute poisoning incidences were observed in all groups during the experiment. CONCLUSIONS: Our findings demonstrate that WZYZW may ameliorate some GTW-induced BTB dysfunction, possibly by regulating proinflammatory cytokine levels. In vitro studies on the regulation of BTB permeability by WZYZW and its active components are further required.


Subject(s)
Blood-Testis Barrier/drug effects , Drugs, Chinese Herbal/pharmacology , Glycosides/toxicity , Inflammation/metabolism , Testis/metabolism , Tripterygium/chemistry , Animals , Cytokines/genetics , Cytokines/metabolism , Gene Expression Regulation/drug effects , Male , Mice , Mice, Inbred C57BL , Random Allocation , Spermatogenesis/drug effects , Testis/blood supply
8.
Transl Androl Urol ; 10(2): 724-733, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33718074

ABSTRACT

BACKGROUND: Erectile dysfunction (ED) shares common risk factors with cardiovascular disease (CVD), such as diabetes mellitus (DM) and dyslipidemia, but the relationship between the risk factors of CVD in biochemical markers and young men with ED age 20-40 years is not fully clarified. METHODS: A total of 289 ED outpatients (20-40 years old) were allocated under ED group, based on patients' complaints and physical examinations. According to the frequency matching ratio of 1:4, 1,155 male individuals (20-40 years old) without ED were set as control group. All participants were tested for lipid profiles including total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), blood glucose (BG), homocysteine (HCY), liver function including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and renal function including uric acid (UA) and creatinine (CR). The study was designed to compare the two groups using an established binary logistic regression analysis model. The ED group was then subdivided into a younger ED group (20-30 years old) and an older ED group (31-40 years old) for further comparisons. RESULTS: After comparison, no obvious differences were found in medians of age, TC, TG, HDL, HCY, UA, and ALT in the two groups. Median LDL, BG, and CR were significantly higher and AST was much lower in the ED group (P<0.01). In binary logistic regression analysis, odds ratios (OR) for LDL, BG, CR, and AST were 1.279, 1.237, 1.026, and 0.978, respectively. The sensitivity value and specificity value were 43.25% and 72.56%, respectively. The medians of LDL, TG, and TC were higher and HDL was much lower in the older ED group, as compared with the younger group (P<0.05). No significant differences were displayed in medians of other biochemical markers in the above comparisons. CONCLUSIONS: Elevated LDL, BG, and CR were related factors of ED in young men. Lipid profile was significantly different between young men with ED aged 20-30 and 31-40 years.

9.
Front Pharmacol ; 12: 752244, 2021.
Article in English | MEDLINE | ID: mdl-35046802

ABSTRACT

Acute myocardial infarction (AMI) is a condition with high morbidity and mortality, for which effective treatments are lacking. Allicin has been reported to exert therapeutic effects on AMI, but the underlying mechanisms of its action have not been fully elucidated. To investigate this, a rat model of AMI was generated by ligating the left anterior descending branch of the coronary artery. DL-propargylglycine (PAG), a specific hydrogen sulfide (H2S) synthetase inhibitor, was used to examine the effects of allicin on H2S production. Isolated coronary arteries and cardiomyocytes were assessed for vascular reactivity and cellular Ca2+ transport using a multiwire myography system and a cell-contraction-ion detection system, respectively. Allicin administration improved cardiac function and myocardial pathology, reduced myocardial enzyme levels, and increased H2S and H2S synthetase levels. Allicin administration resulted in concentration-dependent effects on coronary artery dilation, which were mediated by receptor-dependent Ca2+ channels, ATP-sensitive K+ channels, and sarcoplasmic reticulum (SR) Ca2+ release induced by the ryanodine receptor. Allicin administration improved Ca2+ homeostasis in cardiomyocytes by increasing cardiomyocyte contraction, Ca2+ transient amplitude, myofilament sensitivity, and SR Ca2+ content. Allicin also enhanced Ca2+ uptake via SR Ca2+-ATPase and Ca2+ removal via the Na+/Ca2+ exchanger, and it reduced SR Ca2+ leakage. Notably, the protective effects of allicin were partially attenuated by blockade of H2S production with PAG. Our findings provide novel evidence that allicin-induced production of H2S mediates coronary artery dilation and regulation of Ca2+ homeostasis in AMI. Our study presents a novel mechanistic insight into the anti-AMI effects of allicin and highlights the therapeutic potential of this compound.

10.
Stem Cell Res Ther ; 11(1): 360, 2020 08 18.
Article in English | MEDLINE | ID: mdl-32811548

ABSTRACT

BACKGROUND: The development of new treatment strategies to improve peripheral nerve repair after injury, especially those that accelerate axonal nerve regeneration, is very important. The aim of this study is to elucidate the molecular mechanisms of how bone marrow stromal cell (BMSC)-derived exosomes (EXOs) participate in peripheral nerve regeneration and whether the regenerative effect of EXOs is correlated with dose. METHOD: BMSCs were transfected with or without an siRNA targeting Ago2 (SiAgo2). EXOs extracted from the BMSCs were administered to dorsal root ganglion (DRG) neurons in vitro. After 48 h of culture, the neurite length was measured. Moreover, EXOs at four different doses were injected into the gastrocnemius muscles of rats with sciatic nerve crush injury. The sciatic nerve functional index (SFI) and latency of thermal pain (LTP) of the hind leg sciatic nerve were measured before the operation and at 7, 14, 21, and 28 days after the operation. Then, the number and diameter of the regenerated fibers in the injured distal sciatic nerve were quantified. Seven genes associated with nerve regeneration were investigated by qRT-PCR in DRG neurons extracted from rats 7 days after the sciatic nerve crush. RESULTS: We showed that after 48 h of culture, the mean number of neurites and the length of cultured DRG neurons in the SiAgo2-BMSC-EXO and SiAgo2-BMSC groups were smaller than that in the untreated and siRNA control groups. The average number and diameter of regenerated axons, LTP, and SFI in the group with 0.9 × 1010 particles/ml EXOs were better than those in other groups, while the group that received a minimum EXO dose (0.4 × 1010 particles/ml) was not significantly different from the PBS group. The expression of PMP22, VEGFA, NGFr, and S100b in DRGs from the EXO-treated group was significantly higher than that in the PBS control group. No significant difference was observed in the expression of HGF and Akt1 among the groups. CONCLUSIONS: These results showed that BMSC-derived EXOs can promote the regeneration of peripheral nerves and that the mechanism may involve miRNA-mediated regulation of regeneration-related genes, such as VEGFA. Finally, a dose-effect relationship between EXO treatment and nerve regeneration was shown.


Subject(s)
Crush Injuries , Exosomes , Mesenchymal Stem Cells , Animals , Crush Injuries/genetics , Crush Injuries/therapy , Nerve Regeneration , Rats , Sciatic Nerve
11.
Biomed Pharmacother ; 128: 110240, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32480217

ABSTRACT

BACKGROUND: Allicin, the principle active constituent in garlic, has been reported to have antihypertensive effects on drug-induced hypertension or renal hypertension in rats, but reports on spontaneously hypertensive rats (SHRs) are rare. Allicin is comprised of a variety of sulfur-containing compounds, and hydrogen sulfide (H2S) has been shown to have specific vasomotor effects. We therefore hypothesize that allicin may exert a vasorelaxant activity by inducing H2S production, and this eventually result in a reduction in blood pressure in SHRs. METHODS: The in vivo antihypertensive effect of allicin was assessed using a tail-cuff method on SHRs. The in vitro vasorelaxant effect and in-depth mechanisms of allicin were explored on rat mesenteric arterial rings (RMARs) isolated from SD rats. RESULTS: In the in vivo study, administration of allicin (7 mg/kg and 14 mg/kg, 4 weeks, i.g) dramatically decreased the blood pressure in SHRs, which was also shown to be attenuated by H2S synthase inhibitor (PAG, 32 mg/kg, i.g). In in vitro studies, allicin (2.50-15.77 mM) produced a concentration-dependent vasorelaxation on RMARs, which was obviously reduced by preincubation with PAG. The removal of endothelium led to a decline in allicin's vasorelaxation, which was almost completely mitigated when treatment was followed with PAG. Inhibitors of nitric oxide (NO) and prostaglandin (PGI2) pathways separately suppressed the vasorelaxation induced by allicin to a certain degree. When the RMARs incubated with PAG were treated with or without the above inhibitors in separate groups, the relaxations caused by allicin were almost identical under both these conditions. Moreover, allicin treatment increased cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) levels (downstream products of NO and PGI2 pathways), which was decreased by PAG. Additionally, allicin increased the acetylcholine-induced endothelium-derived hyperpolarizing factor (EDHF) -mediated relaxation, which was unaffected by PAG. CONCLUSION: Allicin exhibits a potent antihypertensive effect through vasodilatory properties and H2S mechanisms. Moreover, the vasodilation of allicin is partially dependent on endothelium. The endothelium-dependent vasodilation of allicin is mediated by the NO-sGC-cGMP, PGI2-AC-cAMP and EDHF pathways, of which H2S participates in the first two but not the third one. The endothelium independent vasodilation can be predominantly attributed to H2S production.


Subject(s)
Antihypertensive Agents/pharmacology , Arterial Pressure/drug effects , Hydrogen Sulfide/metabolism , Hypertension/drug therapy , Mesenteric Arteries/drug effects , Sulfinic Acids/pharmacology , Vasodilation/drug effects , Vasodilator Agents/pharmacology , Animals , Disease Models, Animal , Disulfides , Hypertension/metabolism , Hypertension/physiopathology , Male , Mesenteric Arteries/metabolism , Mesenteric Arteries/physiopathology , Rats, Inbred SHR , Rats, Sprague-Dawley
12.
Chin J Integr Med ; 25(4): 292-297, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30593654

ABSTRACT

OBJECTIVE: To assess the effect of electroacupuncture (EA) on expression of cytoskeletal proteins from Sertoli cells (SCs) and spermatogenesis in rats with oligozoospermia of insufficiency of Shen (Kidney) essence syndrome (OIKES). METHODS: Twenty healthy male Sprague-Dawley rats were randomly assigned to four groups using a random number table: control, tripterygium glycosides (TG) treatment, sham and EA groups (n=5 in each group). A rat model of OIKES was established by oral gavage with TG. The EA group was treated with TG and received EA at Shenshu (BL 23) and Zusanli (ST 36) acupoints for 20 min, once daily for 30 days, while the sham group received EA at identical acupoints with skin penetration without stimulation. After 30 days, the final body weight and coefficients for the testis and epididymis were calculated and sperm parameters were measured. Immunohistochemical analyses were performed to detect expression of vimentin and α-tubulin in SCs and proliferating cell nuclear antigen (PCNA) immunoreactivity in germ cells. Apoptosis in germ cells was quantified by the transferase biotin-dUTP nick end labeling assay. RESULTS: Compared with the control group, the final body weight and testis/epididymis coefficients of rats in the TG-treated group were not significantly different, but the sperm count and motility were lower (P<0.05). Expressions of vimentin and α-tubulin were also significantly weaker (P<0.01). The PCNA immunoreactivity of germ cells was decreased (P=0.059), whereas the apoptotic index of germ cells was increased significantly (P<0.01). In contrast, EA at BL 23 and ST 36 acupoints significantly improved the final body weight as well as the sperm count, concentration and motility (P<0.01 or P<0.05). EA increased expression of vimentin and α-tubulin in SCs markedly, and significantly enhanced PCNA immunoreactivity with decreased apoptosis in germ cells (P<0.01 or P<0.05). CONCLUSIONS: EA at BL 23 and ST 36 acupoints has protective effects on spermatogenesis in rats with OIKES. This effect seems to be achieved by attenuating TG-induced disruption of cytoskeletal protein in SCs.


Subject(s)
Electroacupuncture , Kidney/pathology , Oligospermia/therapy , Spermatogenesis , Animals , Apoptosis , Body Weight , Epididymis/pathology , Male , Proliferating Cell Nuclear Antigen/metabolism , Rats, Sprague-Dawley , Sertoli Cells/metabolism , Spermatozoa/metabolism , Spermatozoa/pathology , Syndrome , Testis/pathology , Vimentin/metabolism
13.
J Org Chem ; 83(22): 13991-14000, 2018 11 16.
Article in English | MEDLINE | ID: mdl-30351053

ABSTRACT

A copper-mediated direct C3 amination of imidazopyridines has been disclosed under additive-free conditions in short reaction times. This methodology utilizes commercially available N-fluorobenzenesulfonimide (NFSI) as the amino source, which exhibits broad substrate scope and good functional group tolerance. The obtained C3-aminated imidazopyridines can undergo further desulfonylation transformations. Control experiments suggest that this reaction probably proceeds via a free-radical mechanism. Moreover, NFSI also shows potential application in C-H fluorination of imidazopyridines.

14.
Biochemistry ; 49(44): 9638-48, 2010 Nov 09.
Article in English | MEDLINE | ID: mdl-20886813

ABSTRACT

Rhodococcus rhodochrous J1 produces high- and low-molecular mass nitrile hydratases (H-NHase and L-NHase, respectively), depending on the inducer. The incorporation of cobalt into L-NHase has been found to depend on the α-subunit exchange between cobalt-free L-NHase (apo-L-NHase) and its cobalt-containing mediator, NhlAE (holo-NhlAE), this novel mode of post-translational maturation having been named self-subunit swapping and NhlE having been recognized as a self-subunit swapping chaperone. We discovered an H-NHase maturation mediator, NhhAG, consisting of NhhG and the α-subunit of H-NHase. The incorporation of cobalt into H-NHase was confirmed to be dependent on self-subunit swapping. For the first time, particles larger than apo-H-NHase were observed during the swapping process via dynamic light scattering measurements, suggesting the formation of intermediate complexes. On the basis of these findings, we initially proposed a possible mechanism for self-subunit swapping. Electron paramagnetic resonance analysis demonstrated that the coordination environment of a cobalt ion in holo-NhhAG is subtly different from that in H-NHase. Cobalt is inserted into cobalt-free NhhAG (apo-NhhAG) but not into apo-H-NHase, suggesting that NhhG functions not only as a self-subunit swapping chaperone but also as a metallochaperone. In addition, α-subunit swapping did not occur between apo-L-NHase and holo-NhhAG or between apo-H-NHase and holo-NhlAE in vitro. These findings revealed that self-subunit swapping is a subunit-specific reaction.


Subject(s)
Hydro-Lyases/chemistry , Hydro-Lyases/metabolism , Rhodococcus/enzymology , Bacterial Proteins/metabolism , Cobalt/metabolism , Metalloproteins/metabolism , Molecular Weight , Protein Multimerization , Protein Subunits/chemistry , Protein Subunits/metabolism , Rhodococcus/chemistry , Rhodococcus/metabolism
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