Crystals of a member of the DING protein family (HPBP) were obtained accidentally, and the structure was determined at 1.35 Å resolution. For further analysis, a system for preparation of HPBP was constructed and the structure of a prepared sample was confirmed by X-ray crystal structure analysis at 1.03 Å resolution.
After crystallization of a certain protein–RNA complex, well diffracting crystals were obtained. However, the asymmetric unit of the crystal was too small to locate any components. Mass spectrometry and X-ray crystal structure analysis showed that it was a member of the DING protein family (HPBP). Surprisingly, the structure of HPBP reported previously was also determined accidentally as a contaminant, suggesting that HPBP has a strong tendency to crystallize. Furthermore, DING proteins were reported to relate in disease. These observations suggest that DING has potential for application in a wide range of research fields. To enable further analyses, a system for preparation of HPBP was constructed. As HPBP was expressed in insoluble form in Escherichia coli, it was unfolded chemically and refolded. Finally, a very high yield preparation method was constructed, in which 43 mg of HPBP was obtained from 1 L of culture. Furthermore, to evaluate the validity of refolding, its crystal structure was determined at 1.03 Å resolution. The determined structure was identical to the native structure, in which two disulfide bonds were recovered correctly and a phosphate ion was captured. Based on these results, it was concluded that the refolded HPBP recovers its structure correctly.
DING; HPBP; crystal structure; overexpression; refolding
AIM: To investigate the dynamic features of insulin-like growth factor-I receptor (IGF-IR) expression in rat hepatocarcinogenesis, and the relationship between IGF-IR and hepatocytes malignant transformation at mRNA or protein level.
METHODS: Hepatoma models were made by inducing with 2-fluorenylacetamide (2-FAA) on male Sprague-Dawley rats. Morphological changes of hepatocytes were observed by pathological Hematoxylin and eosin staining, the dynamic expressions of liver and serum IGF-IR were quantitatively analyzed by an enzyme-linked immunosorbent assay. The distribution of hepatic IGF-IR was located by immunohistochemistry. The fragments of IGF-IR gene were amplified by reverse transcription-polymerase chain reaction, and confirmed by sequencing.
RESULTS: Rat hepatocytes after induced by 2-FAA were changed dynamically from granule-like degeneration, precancerous to hepatoma formation with the progressing increasing of hepatic mRNA or IGF-IR expression. The incidences of liver IGF-IR, IGF-IR mRNA, specific IGF-IR concentration (ng/mg wet liver), and serum IGF-IR level (ng/mL) were 0.0%, 0.0%, 0.63 ± 0.17, and 1.33 ± 0.47 in the control; 50.0%, 61.1%, 0.65 ± 0.2, and 1.51 ± 0.46 in the degeneration; 88.9%, 100%, 0.66 ± 0.14, and 1.92 ± 0.29 in the precancerosis; and 100%, 100%, 0.96 ± 0.09, and 2.43 ± 0.57 in the cancerous group, respectively. IGF-IR expression in the cancerous group was significantly higher (P < 0.01) than that in any of other groups at mRNA or protein level. The closely positive IGF-IR relationship was found between livers and sera (r = 0.91, t = 14.222, P < 0.01), respectively.
CONCLUSION: IGF-IR expression may participate in rat hepatocarcinogenesis and its abnormality should be an early marker for hepatocytes malignant transformation.
Hepatoma; Insulin-like growth factor-I receptor; Immunohistochemistry; Gene amplification; Sequencing; Rat hepatoma model
Mitochondrial dysfunction has been implicated in the pathogenesis of biliary atresia (BA). This study aimed to determine whether a specific mitochondrial DNA haplogroup is implicated in the pathogenesis and prognosis of BA. We determined 40 mitochondrial single nucleotide polymorphisms in 15 major mitochondrial haplogroups by the use of 24-plex PCR and fluorescent beads combined with sequence-specific oligonucleotide probes in 71 patients with BA and in 200 controls in the Taiwanese population of ethnic Chinese background. The haplogroup B4 and E prevalence were significantly lower and higher respectively, in the patients with BA than in the controls (odds ratios, 0.82 [p = 0.007] and 7.36 [p = 0.032] respectively) in multivariate logistic-regression analysis. The 3-year survival rate with native liver was significantly lower in haplogroup E than the other haplogroups (P = 0.037). A cytoplasmic hybrid (cybrid) was obtained from human 143B osteosarcoma cells devoid of mtDNA (ρ0 cell) and was fused with specific mtDNA bearing E and B4 haplogroups donated by healthy Taiwanese subjects. Chenodeoxycholic acid treatment resulted in significantly lower free radical production, higher mitochondrial membrane potential, more viable cells, and fewer apoptotic cybrid B4 cells than parental 143B and cybrid E cells. Bile acid treatment resulted in a significantly greater protective mitochondrial reaction with significantly higher mitochondrial DNA copy number and mitofusin 1 and 2 concentrations in cybrid B4 and parental cells than in cybrid E cells. The results of the study suggested that the specific mitochondrial DNA haplogroups B4 and E were not only associated with lower and higher prevalence of BA respectively, in the study population, but also with differential susceptibility to hydrophobic bile acid in the cybrid harboring different haplogroups.
Mitochondrial dysfunction has been implicated in the pathogenesis of biliary atresia (BA). We determined 40 mitochondrial single nucleotide polymorphisms in different mitochondrial haplogroups in BA patients and controls. The prevalence of haplogroup B4 and E was significantly lower and higher respectively, in the patients with BA than in the controls. The survival rate with native liver was significantly lower in haplogroup E than the other haplogroups. The in vitro study using cybrid cells revealed significantly lower free radical production, higher mitochondrial membrane potential, higher mitochondrial DNA copy number and fewer apoptotic in cybrid B4 cells than cybrid E cells. The study provides a novel insight into the etiopathogenesis and the predictive value of mitochondrial haplogroups in BA.
AIM: To investigate the effects of Annexin A2 (ANXA2) silencing on invasion, migration, and tumorigenic potential of hepatoma cells.
METHODS: Human hepatoma cell lines [HepG2, SMMC-7721, SMMC-7402, and MHCC97-H, a novel human hepatocellular carcinoma (HCC) cell line with high metastasis potential] and a normal hepatocyte cell line (LO2) were used in this study. The protein and mRNA expression levels of ANXA2 were analysed by western blotting and real-time polymerase chain reaction, respectively. The intracellular distribution profile of ANXA2 expression was determined by immunofluorescence and immunohistochemistry. Short hairpin RNA targeting ANXA2 was designed and stably transfected into MHCC97-H cells. Cells were cultured for in vitro analyses or subcutaneously injected as xenografts in mice for in vivo analyses. Effects of ANXA2 silencing on cell growth were assessed by cell counting kit-8 (CCK-8) assay (in vitro) and tumour-growth assay (in vivo), on cell cycling was assessed by flow cytometry and propidium iodide staining (in vitro), and on invasion and migration potential were assessed by transwell assay and wound-healing assay, respectively (both in vitro).
RESULTS: The MHCC97-H cells, which are known to have high metastasis potential, showed the highest level of ANXA2 expression among the four HCC cell types examined; compared to the LO2 cells, the MHCC97-H expression level was 8-times higher. The ANXA2 expression was effectively inhibited (about 80%) by ANXA2-speciﬁc small hairpin RNA (shRNA). ANXA2 expression in the MHCC97-H cells was mainly localized to the cellular membrane and cytoplasm, and some localization was detected in the nucleus. Moreover, the proliferation of MHCC97-H cells was obviously suppressed by shRNA-mediated ANXA2 silencing in vitro, and the tumour growth inhibition rate was 38.24% in vivo. The percentage of MHCC97-H cells in S phase dramatically decreased (to 27.76%) under ANXA2-silenced conditions. Furthermore, ANXA2-silenced MHCC97-H cells showed lower invasiveness (percentage of invading cells decreased to 52.16%) and suppressed migratory capacity (migration distance decreased to 63.49%). It is also worth noting that shRNA-mediated silencing of ANXA2 in the MHCC97-H cells led to abnormal apoptosis.
CONCLUSION: shRNA-mediated silencing of ANXA2 suppresses the invasion, migration, and tumorigenic potential of hepatoma cells, and may represent a useful target of future molecular therapies.
Annexin A2; Small hairpin RNA; Hepatocellular carcinoma; Invasion; Migration; Tumorigenic potential
Crystals of dihydrouridine synthase from Thermus thermophilus and its complex with tRNA were obtained and X-ray diffraction data were collected to 1.70 and 3.51 Å resolution, respectively.
Dihydrouridine synthase (Dus) is responsible for catalyzing dihydrouridine formation in RNA by the reduction of uridine. To elucidate its RNA-recognition mechanism, Dus from Thermus thermophilus (TthDus) and its complex with tRNA were crystallized. Diffraction data sets were collected from crystals of native and selenomethionine-substituted TthDus to resolutions of 1.70 and 2.30 Å, respectively. These crystals belonged to space group P1. Preliminary X-ray crystallographic analysis showed that two molecules of TthDus were contained in an asymmetric unit. In addition, diffraction data were collected to 3.51 Å resolution from a crystal of selenomethionine-substituted TthDus in complex with tRNA, which belonged to space group P41212. Preliminary structural analysis showed that the asymmetric unit contained two TthDus–tRNA complexes.
dihydrouridine synthase; tRNA; flavin mononucleotide; Thermus thermophilus
The eukaryotic translation initiation factor eIF5BΔN and the eIF5BΔN–eIF1AΔN complex from S. cerevisiae were crystallized. The crystals diffracted to maximum resolutions of 2.45 and 3.3 Å, respectively.
The binding between two universally conserved translation initiation factors, eIF5B and eIF1A, is important in the initiation step of eukaryotic protein synthesis on the ribosome. Through this interaction, eIF1A assists in recruiting eIF5B to the initiating 40S subunit; eIF5B then encourages the joining of the 60S subunit to form an initiating 80S ribosome. Here, the expression, purification, crystallization and preliminary X-ray analyses of eIF5BΔN and the eIF5BΔN–eIF1AΔN complex from Saccharomyces cerevisiae are reported. The crystal of eIF5BΔN diffracted to 2.45 Å resolution and belonged to space group P41212, with unit-cell parameters a = b = 130.0, c = 71.7 Å. The asymmetric unit was estimated to contain one molecule. The initial phase was obtained by Se-SAD. The crystal of the eIF5BΔN–eIF1AΔN complex diffracted to 3.3 Å resolution and belonged to space group P212121, with unit-cell parameters a = 101.9, b = 120.9, c = 132.8 Å. The asymmetric unit was estimated to contain two complex molecules.
eukaryotic translation initiation; ribosomal subunit joining; initiation factor eIF5B; eIF5B–eIF1A interaction
Crystals of a geranyl pyrophosphate methyltransferase in the biosynthetic pathway of the off-flavor terpenoid alcohol, 2-methylisoborneol were obtained in the absence and presence of cofactor, cofactor analog and substrate.
The biosynthetic pathway of the off-flavour terpenoid alcohol 2-methylisoborneol (2-MIB) requires geranyl pyrophosphate methyltransferase (GPPMT) to methylate GPP before the cyclization reaction. GPPMT is the first example of an S-adenosyl-l-methionine-dependent methyltransferase that acts on general intermediates such as geranyl pyrophosphate and farnesyl pyrophosphate in isoprenoid biosynthetic pathways. In this study, recombinant GPPMT was overproduced, purified and crystallized in the absence and presence of cofactor, cofactor analogue and substrate. Well diffracting crystals of apo GPPMT containing one molecule in the asymmetric unit were obtained and the structure of this form was solved by the molecular-replacement method. Two crystal forms of the tertiary complex with GPP and sinefungin were also obtained. Structure analysis of these crystals is currently under way in order to understand the enzyme reaction mechanism.
geranyl pyrophosphate methyltransferase; 2-methylisoborneol biosynthesis; Streptomyces lasaliensis
Nowadays methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common multidrug resistant bacteria both in hospitals and in the community. In the last two decades, there has been growing concern about the increasing resistance to MRSA of the most potent antibiotic glycopeptides. MRSA infection poses a serious problem for physicians and their patients. Photosensitizer-mediated antimicrobial photodynamic therapy (PDT) appears to be a promising and innovative approach for treating multidrug resistant infection. In spite of encouraging reports of the use of antimicrobial PDT to inactivate MRSA in large in vitro studies, there are only few in vivo studies. Therefore, applying PDT in the clinic for MRSA infection is still a long way off.
Hemodynamic monitoring is very important in critically ill patients with shock or acute respiratory distress syndrome(ARDS). The PiCCO (Pulse index Contour Continuous Cardiac Output, Pulsion Medical Systems, Germany) system has been developed and used in critical care settings for several years. However, its impact on clinical outcomes remains unknown.
The study is a randomized controlled multi-center trial. A total of 708 patients with ARDS, septic shock or both will be included from January 2012 to January 2014. Subjects will be randomized to receive PiCCO monitoring or not. Our primary end point is 30-day mortality, and secondary outcome measures include ICU length of stay, days on mechanical ventilation, days of vasoactive agent support, ICU-free survival days during a 30-day period, mechanical-ventilation-free survival days during a 30-day period, and maximum SOFA score during the first 7 days.
We investigate whether the use of PiCCO monitoring will improve patient outcomes in critically ill patients with ARDS or septic shock. This will provide additional data on hemodynamic monitoring and help clinicians to make decisions on the use of PiCCO.
Pulse index Contour Continuous Cardiac Output; Shock; Acute respiratory distress syndrome; Mortality
In animal ribosomes, two stalk proteins P1 and P2 form a heterodimer, and the two dimers, with the anchor protein P0, constitute a pentameric complex crucial for recruitment of translational GTPase factors to the ribosome. To investigate the functional contribution of each copy of the stalk proteins, we constructed P0 mutants, in which one of the two C-terminal helices, namely helix I (N-terminal side) or helix II (C-terminal side) were unable to bind the P1–P2 dimer. We also constructed ‘one-C-terminal domain (CTD) stalk dimers’, P1–P2ΔC and P1ΔC–P2, composed of intact P1/P2 monomer and a CTD-truncated partner. Through combinations of P0 and P1–P2 variants, various complexes were reconstituted and their function tested in eEF-2-dependent GTPase and eEF-1α/eEF-2-dependent polyphenylalanine synthesis assays in vitro. Double/single-CTD dimers bound to helix I showed higher activity than that bound to helix II. Despite low polypeptide synthetic activity by a single one-CTD dimer, its binding to both helices considerably increased activity, suggesting that two stalk dimers cooperate, particularly in polypeptide synthesis. This promotion of activity by two stalk dimers was lost upon mutation of the conserved YPT sequence connecting the two helices of P0, suggesting a role for this sequence in cooperativity of two stalk dimers.
Background. Osteoporosis is a major health problem for the elderly population. Chinese herb may be beneficial to osteoporosis due to its capability. Objectives. This study was designed to evaluate the effectiveness of Chinese medicine treatment on the patients with osteoporosis. Search Methods. Randomized controlled trials were retrieved from different 9 databases. Results. This meta analysis included 12 RCTs involving 1816 patients to compare Chinese herbs with placebo or standard anti-osteoporotic therapy in the treatment of bone loss. The pooled data showed that the percent change of increased BMD in the spine is higher with Chinese herb compared to placebo (lumber spine: WMD = 0.07, 95% CI: 0.01–0.04). In the femoral, Chinese herb showed significantly higher increments of BMD compared to placebo (femoral neck: WMD = 0.06, 95% CI: −0.02–0.13). Compared to the other standard anti-osteoporotic drugs, Chinese herbs also show advantage in BMD change (lumber spine: WMD = 0.03, 95% CI: −0.01–0.08; femoral: WMD = 0.01, 95% CI: −0.01–0.02). Conclusions. Our results demonstrated that Chinese herb significantly increased lumbar spine BMD as compared to the placebo or other standard anti-osteoporotic drugs.
Hepatocellular carcinoma (HCC) is a highly chemoresistant cancer with no effective systemic therapy. Despite of surgical or locoregional therapies, prognosis remains poor because of high tumor recurrence or progression, and currently, there are no well-established effective adjuvant therapies. Glypican-3 (GPC-3) is specifically overexpressed in hepatoma and perhaps is a valuable molecular target for HCC therapy. In this present study, the effect of silencing GPC-3 gene transcription on human HepG2 cell proliferation was investigated by constructing GPC-3 short hairpin RNA (shRNA) plasmid. After HepG2 cells were transfected with the most efficient shRNA, GPC-3 mRNA expression (90.4 %) was inhibited significantly and estimated by fluorescence quantitative reverse transcriptase-polymerase chain reaction, and the result was accordance with downregulation at the protein level. The percentage of the cell proliferation was down to 28.9 % in the shRNA group and 19.9 % in the shRNA plus sorafenib group. The cell cycles were arrested in the G1 phase (65.6 %) and the apoptosis rate was increasing (66.75 %) in the shRNA1 group with significant alteration compared with that in the negative-shRNA group. Specific shRNA might intervene effectively GPC-3 activation and inhibit tumor cell proliferation, suggesting that GPC-3 gene should be a potential molecular target for HCC therapy.
Hepatocellular carcinoma; Glypican-3; shRNA; Transfection; Gene silencing
AIM: To investigate the characteristics and diagnostic value of annexin A2 (ANXA2) expression in cancerous tissues and sera of patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).
METHODS: Levels of liver ANXA2 gene transcription or protein expression were analyzed in HCC-, their self-controlled precancerous-, and distant cancerous- tissues from 30 HCC. Serum levels of ANXA2 expression in 115 patients with HCC, 25 with metastatic liver cancer, 35 with chronic hepatitis, 28 with acute hepatitis, 38 with cirrhosis, and 30 healthy controls were determined. Clinicopathological characteristics of circulating ANXA2 expression were analyzed, and its diagnostic efficiency and clinical values in HCC were evaluated.
RESULTS: ANXA2 expression was localized in both cell membrane and cytoplasm in HCC tissue, mainly in the cytoplasm of matched adjacent cancerous tissue, and there was almost no positive staining in matched distant cancerous tissue. Abnormal expression of liver ANXA2 was present in HCC tissues compared with self-controlled adjacent- and distant-cancerous tissues at protein or mRNA level. Circulating ANXA2 in HCC patients was significantly higher than that of other liver diseases (P < 0.01) except metastatic liver cancer. If the diagnostic cutoff value of ANXA2 level was more than 18 ng/mL, the incidence of serum ANXA2 was 86.96% in the HCC group, 80% in the metastatic liver cancer group, 31.58% in the liver cirrhosis group, none in the chronic hepatitis or acute hepatitis or normal control group, respectively. Serum ANXA2 expression in HCC patients was correlated with HBV infection (27.38 ± 5.67 ng/mL vs 18.58 ± 7.83 ng/mL, P < 0.01), extrahepatic metastasis (26.11 ± 5.43 ng/mL vs 22.79 ± 5.64 ng/mL, P < 0.01), and portal vein thrombus (26.03 ± 5.99 ng/mL vs 23.06 ± 5.03 ng/mL, P < 0.01), and was significantly higher (P < 0.01) in the moderately- (26.19 ± 5.34 ng/mL) or the poorly- differentiated group (27.05 ± 5.13 ng/mL) than in the well differentiated group (20.43 ± 4.97 ng/mL), and in the tumor node metastasis stages III-IV (P < 0.01) than in stages I-II. ANXA2 was not correlated with patient sex, age, size or α-fetoprotein (AFP) level. Area under the receiver operating characteristic curve for the whole range of sensitivities and specificities was 0.796 for ANXA2 and 0.782 for AFP. Combining detection of serum ANXA2 and AFP substantially improved the diagnostic efficiency (96.52%) and the negative predictive value (96.61%) for HCC.
CONCLUSION: The characteristics and distribution of ANXA2 expression has good diagnostic potential for HCC diagnosis.
Hepatocellular carcinoma; Annexin A2; Liver; Upregulation; Clinicopathological characteristics; Diagnosis; Expression; Biomarker
There is overwhelming evidence that dietary supplementation with n-3 polyunsaturated fatty acids (PUFAs), mainly EPA (C20:5n-3) and DHA (C22:6n-3), has cardiovascular protective effects on patients with type 2 diabetes mellitus (T2DM) but not on healthy people. Because the T2DM heart increases fatty acid oxidation (FAO) to compensate for the diminished utilization of glucose, we hypothesize that T2DM hearts consume more n-3 PUFAs and, therefore, need more n-3 PUFAs. In the present study, we investigated the changes in cardiac n-3 PUFAs and peroxisomal beta-oxidation, which are responsible for the degradation of PUFAs in a high-fat diet (HFD) and low-dose streptozotocin- (STZ) induced type 2 diabetic rat model.
Methods and results
The capillary gas chromatography results showed that all the n-3 (or omega-3) PUFAs, especially DHA (~50%) and EPA (~100%), were significantly decreased, and the n-6/n-3 ratio (~115%) was significantly increased in the hearts of diabetic rats. The activity of peroxisomal beta-oxidation, which is crucial to very-long-chain and unsaturated FA metabolism (including DHA), was significantly elevated in DM hearts. Additionally, the real-time PCR results showed that the mRNA expression of most peroxisomal beta-oxidation key enzymes were up-regulated in T2DM rat hearts, which might contribute to the reduction of n-3 (or omega-3) PUFAs.
In conclusion, our results indicate that T2DM hearts consume more n-3 PUFAs, especially DHA and EPA, due to exaggerated peroxisomal beta-oxidation.
n-3 PUFA; EPA; DHA; T2DM; FAO; Peroxisomal β-oxidation
Quinoxaline 1, 4-dioxides (QdNOs) has been used in animals as antimicrobial agents and growth promoters for decades. However, the resistance to QdNOs in pathogenic bacteria raises worldwide concern but it is barely known. To explore the molecular mechanism involved in development of QdNOs resistance in Escherichia coli, 6 strains selected by QdNOs in vitro and 21 strains isolated from QdNOs-used swine farm were subjected to MIC determination and PCR amplification of oqxA gene. A conjugative transfer was carried out to evaluate the transfer risk of QdNOs resistant determinant. Furthermore, the transcriptional profile of a QdNOs-resistant E. coli (79O4-2) selected in vitro with its parent strain 79–161 was assayed with a prokaryotic suppression subtractive hybridization (SSH) PCR cDNA subtraction. The result showed that more than 95% (20/21) clinical isolates were oqxA positive, while all the 6 induced QdNOs-resistant strains carried no oqxA gene and exhibited low frequency of conjugation. 44 fragments were identified by SSH PCR subtraction in the QdNOs-resistant strain 79O4-2. 18 cDNAs were involved in biosynthesis of Fe-S cluster (narH), protein (rpoA, trmD, truA, glyS, ileS, rplFCX, rpsH, fusA), lipoate (lipA), lipid A (lpxC), trehalose (otsA), CTP(pyrG) and others molecular. The 11 cDNAs were related to metabolism or degradation of glycolysis (gpmA and pgi) and proteins (clpX, clpA, pepN and fkpB). The atpADG and ubiB genes were associated with ATP biosynthesis and electron transport chain. The pathway of the functional genes revealed that E. coli may adapt the stress generated by QdNOs or develop specific QdNOs-resistance by activation of antioxidative agents biosynthesis (lipoate and trehalose), protein biosynthesis, glycolysis and oxidative phosphorylation. This study initially reveals the possible molecular mechanism involved in the development of QdNOs-resistance in E. coli, providing with novel insights in prediction and assessment of the emergency and horizontal transfer of QdNOs-resistance in E. coli.
Radiocontrast-induced nephropathy (RCIN) is an acute and severe complication after coronary angiography, particularly for patients with pre-existing chronic kidney disease (CKD). It has been associated with both short- and long-term adverse outcomes, including the need for renal replacement therapy, increased length of hospital stay, major cardiac adverse events, and mortality. RCIN is generally defined as an increase in serum creatinine concentration of 0.5 mg/dL or 25% above baseline within 48 h after contrast administration. There is no effective therapy once injury has occurred, therefore, prevention is the cornerstone for all patients at risk for acute kidney injury (AKI). There is a small but growing body of evidence that prevention of AKI is associated with a reduction in later adverse outcomes. The optimal strategy for preventing RCIN has not yet been established. This review discusses the principal risk factors for RCIN, evaluates and summarizes the evidence for RCIN prophylaxis, and proposes recommendations for preventing RCIN in CKD patients undergoing coronary angiography.
Acute kidney injury; Contrast media; Coronary angiography; N-acetylcysteine; Radiocontrast-induced nephropathy
In order to determine the structure–function relationship of the azo-dye reduction mechanism, an X-ray crystallographic study of azoreductases was performed. Selenomethionine-labelled AzrA (SeMet-AzrA) and AzrC were crystallized by the hanging-drop vapour-diffusion method.
Azoreductases from Bacillus sp. B29 are NADH-dependent flavoenzymes which contain a flavin mononucleotide (FMN) as a prosthetic group and exist as homodimers composed of 23 kDa subunits. These enzymes catalyze the reductive degradation of various azo compounds by a ping-pong mechanism. In order to determine the structure–function relationship of the azo-dye reduction mechanism, an X-ray crystallographic study of azoreductases was performed. Selenomethionine-labelled AzrA (SeMet-AzrA) and AzrC were crystallized by the hanging-drop vapour-diffusion method. A crystal of SeMet-AzrA diffracted to 2.0 Å resolution and was determined to belong to space group P212121, with unit-cell parameters a = 56.9, b = 69.0, c = 105.4 Å. The native crystals of AzrC belonged to space group C2, with unit-cell parameters a = 192.0, b = 56.6, c = 105.5 Å, β = 115.7°, and diffracted to 2.21 Å resolution.
azoreductases; NADH-dependent oxidoreductases; flavoproteins; Bacillus sp. B29
To determine the binding mechanism of BoNT/OFD05 and its ganglioside receptors on neuronal cells, recombinant BoNT/OFD05 receptor-binding domain has been expressed, purified and crystallized.
Botulinum toxin (BoNT) from Clostridium botulinum OFD05, isolated from bovine botulism, is a D/C mosaic-type BoNT. BoNTs possess binding, translocation and catalytic domains. The BoNT/OFD05 binding domain exhibits significant sequence identity to BoNT/C, which requires a single ganglioside as a binding receptor on neuronal cells, while BoNT/A and BoNT/B require two receptors for specific binding. To determine the binding mechanism of BoNT/OFD05 and its ganglioside receptors on neuronal cells, recombinant BoNT/OFD05 receptor-binding domain has been expressed, purified and crystallized. Native and SeMet-derivative crystals showed X-ray diffraction to 2.8 and 3.1 Å resolution, respectively. The crystals belonged to space group P212121.
botulinum toxins; Clostridium botulinum strain OFD05; D/C mosaic-type BoNT; receptor-binding domain
Hypoxia-inducible factor-1 (HIF-1) is a ubiquitously expressed oxygen-regulated transcription factor composed of α and β subunits. HIF-1 activates the transcription of various genes including those involved in the formation and metastatic growth of hepatocellular carcinoma (HCC).
To investigate the levels of hepatic and circulating HIF-1α expression in a range of patients with liver disease in order to determine how it can be used in the diagnosis of HCC and in establishing prognosis.
Patients and Methods
Total RNA was extracted from a self-controlled HCC and paracancerous specimen. HIF-1α mRNA was amplified by nested RT-PCR and confirmed by sequencing. Tissue HIF-1α was analyzed by immunohistochemistry. The levels of HIF-1α, vascular endothelial growth factor (VEGF), and angiopoietin-2 (Ang-2) expression in the sera of 220 patients with liver disease were quantitatively detected by ELISA.
The positive staining of liver HIF-1α was brown and granule-like and was mainly present in the cytoplasm, with lower levels in the nucleus of hepatocytes. Its incidence was 80% in HCC cells and 100% in paracancerous tissues, with no significant difference in HIF-1α expression in relation to tumor number, degree of differentiation, or hepatitis B surface antigen (HBsAg) positivity, but with some correlation between HIF-1α and tumor size. HIF-1α expression was detected in the sera of HCC patients at a significantly higher level than in cases of benign liver disease, with pathological characteristics associated with the levels of circulating VEGF and Ang-2 expression, the size of the tumor, and the level of extrahepatic metastasis, but not with patients’ gender, age, or alpha-fetoprotein (AFP) levels.
Hepatic HIF-1α expression is associated with the development and prognosis of HCC, and circulating HIF-1α level is a useful marker for HCC diagnosis and prognosis.
Hypoxia-Inducible Factor 1, alpha Subunit; Carcinoma, Hepatocellular; Gene Expression; Vascular Endothelial Growth Factor; Angiopoietin-2
The current study was designed to investigate the mechanisms by which ropivacaine may act within the central nervous system (CNS) to produce cardiotoxicity. Eighty New Zealand rabbits were divided into four groups randomly. In Group 1, 20 rabbits received intracerebroventricular (icv) saline, and then received icv ropivacaine 30 min later. In Group 2, 20 rabbits received icv ropivacaine. Whenever dysrhythmias continued for more than 5 min, 0.1 ml saline was administered into the left cerebral ventricle. Ten minutes later, 0.1 ml midazolam was given into the left lateral ventricle. In Group 3, 20 rabbits received icv ropivacaine, and once the dysrhythmias developed, the inspired isoflurane concentration was increased from 0.75% to 1.50%. In Group 4, 20 animals received an intravenous (iv) phenylephrine infusion until dysrhythmias occurred. In Group 1, the rabbits did not develop dysrhythmias in response to icv saline, whereas dysrhythmias did develop in these animals after icv ropivacaine. In Group 2, icv saline had no effect on the dysrhythmias; however, icv midazolam terminated cardiac dysrhythmias. In Group 3, an increase in the concentration of the inspired isoflurane had no effect on dysrhythmias. In Group 4, icv midazolam had no effect on dysrhythmias in response to iv phenylephrine. Ropivacaine administered directly into the CNS is capable of producing cardiac dysrhythmias; midazolam terminated dysrhythmias presumably by potentiation of γ-aminobutyric acid (GABA) receptor activity. Our results suggest that ropivacaine produces some of its cardiotoxicity not only by the direct cardiotoxicity of the drug, but also by the CNS effects of ropivacaine.
Ropivacaine; Cardiotoxicity; Ventricular cerebrospinal fluid; Central nervous system (CNS); Dysrhythmias; Midazolam
In the title compound, [CuCl2(C26H18N4)]n, the Cu(II) ion is four-coordinated by two N atoms from two 4,4′-bis(benzoimidazol-1-yl)biphenyl ligands and two chloride anions, in a slightly distorted tetrahedral environment. The biphenyl ligand acts as a linear bidentate ligand, connecting the metal atoms into an infinite chain parallel to . In the biphenyl ligand, the two benzene rings make a dihedral angle of 33.19 (7)°.
An RNA-binding region of human HuR bound to an 11-base RNA fragment has been crystallized. The crystals diffracted to a resolution of 1.8 Å and belonged to space group P212121.
Adenylate/uridylate-rich elements (AREs), which are found in the 3′-untranslated region (UTR) of many mRNAs, influence the stability of cytoplasmic mRNA. HuR (human antigen R) binds to AREs and regulates various genes. In order to reveal the RNA-recognition mechanism of HuR protein, an RNA-binding region of human HuR containing two N-terminal RNA-recognition motif domains bound to an 11-base RNA fragment has been crystallized. The crystals belonged to space group P212121, with unit-cell parameters a = 42.4, b = 44.9, c = 91.1 Å. X-ray diffraction data were collected to 1.8 Å resolution.
HuR; RNA-binding protein; post-transcriptional regulation
Six new sterols (1-6), together with seven known sterols (7-13), were isolated from the CCl4 extract of the marine bryozoan Cryptosula pallasiana, four (3-6) of which have already been reported as synthetic sterols. This is the first time that these compounds (3-6) are reported as natural sterols. The structures of the new compounds were determined on the basis of the extensive spectroscopic analysis, including two-dimensional (2D) NMR and HR-ESI-MS data. Compounds 1-4, 7 and 10-13 were evaluated for their cytotoxicity against HL-60 human myeloid leukemia cell line, and all of the evaluated compounds exhibited moderate cytotoxicity to HL-60 cells with a range of IC50 values from 14.73 to 22.11 µg/mL except for compounds 12 and 13.
marine bryozoan; Cryptosula pallasiana; oxygenated sterols; cytotoxicity
In the title compound, C19H18Br2O2, the dihedral angle between the two benzene rings of the spirobiindane molecule is 70.44 (8)°. In the crystal, molecules are interconnected along the c axis by C—H⋯O hydrogen bonds and π–π stacking [centroid–centroid distance = 3.893 (2) Å] interactions, forming an infinite chain structure. The chains are further interconnected through another set of C—H⋯O hydrogen bonds, forming layers approximately parallel to the bc plane.
Influenza A virus (IAV) infection markedly up-regulates ectopic trypsins in various organs, viral envelope glycoprotein processing proteases, which are pre-requisites for virus entry and multiplication. We investigated the pathological roles of trypsin up-regulation in the progression of IAV-induced myocarditis, cytokine induction, and viral replication in the hearts, and also investigated the protective effects of trypsin inhibitor on cardiac dysfunction in vivo and selective knockdown of trypsin on IAV-induced cellular damage in cardiomyoblasts.
Methods and results
The relationship of the expression among IAV RNA, trypsins, matrix metalloproteinase (MMP)-9, MMP-2, pro-inflammatory cytokines interleukin (IL)-6, IL-1β, and tumour necrosis factor-α was analysed in mice hearts and cardiomyoblasts after IAV infection. The severity of myocarditis was most noticeable during Day 6–9 post-infection, along with peak expression of viral RNA, trypsins, particularly trypsin2, MMPs, and cytokines. Cardiac ATP levels were the lowest at Day 9. Up-regulated trypsins, viral protein, and tissue-injured loci in the myocardium were closely localized. Trypsin inhibitor aprotinin treatment in vivo and selective trypsin1- and trypsin2-knockdown, particularly the latter, in H9c2 cardiomyoblasts significantly suppressed viral replication, up-regulation of MMPs, and production of active MMP-9 and cytokines, resulting in marked protection against cellular damage, ATP depletion, and apoptosis. IAV infection-induced cardiac dysfunction monitored by echocardiography was improved significantly by aprotinin treatment.
IAV-induced trypsins, particularly trypsin2, in the myocardium trigger acute viral myocarditis through stimulation of IAV replication, proMMP-9 activation, and cytokine induction. These results suggest that up-regulation of trypsins is one of the key host pathological findings in IAV-induced myocarditis.
Myocarditis; trypsin; Influenza virus; Cytokines; Matrix metalloproteases