NAMPT suppresses glucose deprivation-induced oxidative stress by increasing NADPH levels in breast cancer

Nicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme involved in NAD+ biosynthesis. Although NAMPT has emerged as a critical regulator of metabolic stress, the underlying mechanisms by which it regulates metabolic stress in cancer cells have not been completely elucidated. In this study, we determined that breast cancer cells expressing a high level of NAMPT were resistant to cell death induced by glucose depletion. Furthermore, NAMPT inhibition suppressed tumor growth in vivo in a xenograft model. Under glucose deprivation conditions, NAMPT inhibition was found to increase the mitochondrial reactive oxygen species (ROS) level, leading to cell death. This cell death was rescued by treatment with antioxidants or NAD+. Finally, we showed that NAMPT increased the pool of NAD+ that could be converted to NADPH through the pentose phosphate pathway and inhibited the depletion of reduced glutathione under glucose deprivation. Collectively, our results suggest a novel mechanism by which tumor cells protect themselves against glucose deprivation-induced oxidative stress by utilizing NAMPT to maintain NADPH levels.

Production of rapamycin in Streptomyces hygroscopicus from glycerol-based media optimized by systemic methodology

Rapamycin, produced by the soil bacterium Streptomyces hygroscopicus, has the ability to suppress the immune system and is used as an antifungal, anti-inflammatory, antitumor, and immunosuppressive agent. In an attempt to increase the productivity of rapamycin, mutagenesis of wild-type Streptomyces hygroscopicus was performed using ultraviolet radiation, and the medium composition was optimized using glycerol (which is one of the cheapest starting substrates) by applying Plackett-Burman design and response surface methodology. Plackett-Burman design was used to analyze 14 medium constituents: M100 (maltodextrin), glycerol, soybean meal, soytone, yeast extract, (NH4)2SO4, L-lysine, KH2PO4, K2HPO4, NaCl, FeSO4·7H2O, CaCO3, 2-(N-morpholino) ethanesulfonic acid, and the initial pH level. Glycerol, soytone, yeast extract, and CaCO3 were analyzed to evaluate their effect on rapamycin production. The individual and interaction effects of the four selected variables were determined by Box-Behnken design, suggesting CaCO3, soytone, and yeast extract have negative effects, but glycerol was a positive factor to determine rapamycin productivity. Medium optimization using statistical design resulted in a 45% (220.7 ± 5.7 mg/l) increase in rapamycin production for the Streptomyces hygroscopicus mutant, compared with the unoptimized production medium (151.9 ± 22.6 mg/l), and nearly 588% compared with wildtype Streptomyces hygroscopicus (37.5 ± 2.8 mg/l). The change in pH showed that CaCO3 is a critical and negative factor for rapamycin production.

Consolidated conversion of protein waste into biofuels and ammonia using Bacillus subtilis

The non-recyclable use of nitrogen fertilizers in microbial production of fuels and chemicals remains environmentally detrimental. Conversion of protein wastes into biofuels and ammonia by engineering nitrogen flux in Escherichia coli has been demonstrated as a method to reclaim reduced-nitrogen and curb its environmental deposition. However, protein biomass requires a proteolysis process before it can be taken up and converted by any microbe. Here, we metabolically engineered Bacillus subtilis to hydrolyze polypeptides through its secreted proteases and to convert amino acids into advanced biofuels and ammonia fertilizer. Redirection of B. subtilis metabolism for amino-acid conversion required inactivation of the branched-chain amino-acid (BCAA) global regulator CodY. Additionally, the lipoamide acyltransferase (bkdB) was deleted to prevent conversion of branched-chain 2-keto acids into their acyl-CoA derivatives. With these deletions and heterologous expression of a keto-acid decarboxylase and an alcohol dehydrogenase, the final strain produced biofuels and ammonia from an amino-acid media with 18.9% and 46.6% of the maximum theoretical yield. The process was also demonstrated on several waste proteins. The results demonstrate the feasibility of direct microbial conversion of polypeptides into sustainable products.

Identification of the specific electron transfer proteins, ferredoxin, and ferredoxin reductase, for CYP105D7 in Streptomyces avermitilis MA4680

It was previously proposed that regiospecific hydroxylation of daidzein at 3'-position is mediated by cytochrome P450 hydroxylase (CYP105D7) in the presence of putidaredoxin (CamB) and putidaredoxin reductase (CamA) as electron transfer proteins from Pseudomonas putida. The genome sequence of Streptomyces avermitilis MA4680 revealed 33 P450 (CYPs) with 6 ferredoxin reductases (Fprs) and 9 ferredoxins (Fdxs) as their putative electron transfer partner proteins. To identify right endogenous electron transfer proteins for CYP105D7 activity, in vitro reconstitution, gene disruption, and quantitative reverse transcription polymerase chain reaction (qRT-PCR) mRNA expression profile analysis were examined. The most effective electron transfer proteins for CYP105D7 appear to be FdxH (SAV7470), which is located downstream to CYP105D7 as a cluster, and FprD (SAV5675). Throughout our overall analysis, we proposed that the primary electron transfer pathway for CYP105D7 follows as such NAD(P)H→FdxH→FprD→CYP105D7.

Development of colorimetric HTS assay of cytochrome p450 for ortho-specific hydroxylation, and engineering of CYP102D1 with enhanced catalytic activity and regioselectivity

A current challenge in high-throughput screening (HTS) of hydroxylation reactions by P450 is a fast and sensitive assay for regioselective hydroxylation against millions of mutants. We have developed a solid-agar plate-based HTS assay for screening ortho-specific hydroxylation of daidzein by sensing formaldehyde generated from the O-dealkylation reaction. This method adopts a colorimetric dye, pararosaniline, which has previously been used as an aldehyde-specific probe within cells. The rationale for this method lies in the fact that the hydroxylation activity at ortho-carbon position to COH correlates with a linear relationship to O-dealkylation activity on chemically introduced methoxy group at the corresponding COH. As a model system, a 4',7-dihydroxyisoflavone (daidzein) hydroxylase (CYP102D1 F96V/M246I), which catalyzes hydroxylation at ortho positions of the daidzein A/B-ring, was examined for O-dealklyation activity, by using permethylated daidzein as a surrogate substrate. By using the developed indirect bishydroxylation screening assay, the correlation coefficient between O-dealkylation and bishydroxylation activity for the template enzyme was 0.72. For further application of this assay, saturation mutants at A273/G274/T277 were examined by mutant screening with a permethylated daidzein analogue substrate (A-ring inactivated in order to find enhanced 3'-regioselectiviy). The whole-cell biotransformation of daidzein by final screened mutant G1 (A273H/G274E/T277G) showed fourfold increased conversion yield, with 14.3 mg L(-1) production titer and greatly increased 3'-regioselectiviy (3'/6=11.8). These results show that there is a remarkably high correlation (both in vitro and in vivo), thus suggesting that this assay would be ideal for a primary HTS assay for P450 reactions.

Production of a novel O-methyl-isoflavone by regioselective sequential hydroxylation and O-methylation reactions in Streptomyces avermitilis host system

Distinct isoflavone O-methyltransferases (IOMTs) from Streptomyces species were isolated and expressed using S. avermitilis host system. Previously reported isoflavone 7-O-methyltransferases (I7OMTs, E.C. 2.1.1.150) and two putative O-methyltransferases (OMTs) from Saccharopolyspora erythraea were selected by comparative sequence grouping and expressed in S. avermitilisΔSaOMT2 under the control of constitutive ermE promoter. During whole-cell biotransformation of 4',7-dihydroxyisoflavone (daidzein) by constructed recombinant strains, production of O-methylated daidzein was investigated. S. avermitilisΔSaOMT2::SeOMT3 (SeOMT3) produced 7-methoxy-4'-hydroxyisoflavone (7-OMD) with 4.5% of low conversion yield due to competitive oxidation reactions. However, SeOMT3 could produce a novel 4',7-dihydroxy-3'-methoxyisoflavone (3'-OMD) (<1%) resulted from subsequent 3'-O-methylation of 3',4',7-trihydroxyisoflavone (3'-OHD) which was a hydroxylated product catalyzed by oxygenases. Although external addition of SAM did not change the conversion yield of O-methylation reaction, co-expression of SAM synthetase gene (metK) with SeOMT3 greatly induced the regiospecific O-methylation reaction at 3'-hydroxyl group with final conversion of 12.1% using 0.1 mM of daidzein.

Phosphorylation of chloramphenicol by a recombinant protein Yhr2 from Streptomyces avermitilis MA4680

Although phosphorylation of chloramphenicol has been shown to occur in the chloramphenicol producer, Streptomyces venezuelae, there are no reports on the existence of chloramphenicol phosphorylase in other Streptomyces species. In the present study, we report the modification of chloramphenicol by a recombinant protein, designated as Yhr2 (encoded by SAV_877), from Streptomyces avermitilis MA4680. Recombinant Yhr2 was expressed in Escherichia coli BL21 (DE3) and the cells expressing this recombinant protein were shown to phosphorylate chloramphenicol to a 3'-O-phosphoryl ester derivative, resulting in an inactivated form of the antibiotic. Expression of yhr2 conferred chloramphenicol resistance to E. coli cells up to 25 μg/mL and in an in vitro reaction, adenosine triphosphate (ATP), guanosine triphosphate (GTP), adenosine diphosphate (ADP) and guanosine diphosphate (GDP) were shown to be the phosphate donors for phosphorylation of chloramphenicol. This study highlights that antibiotic resistance conferring genes could be easily expressed and functionalized in other organisms that do not produce the respective antibiotic.

Identification and functional characterization of an α-amylase with broad temperature and pH stability from Paenibacillus sp

Amylases are important industrial enzymes that have been applied widely in the food, detergent, and pulp industries and fermentation processes. In the present study, a gene encoding an alpha-amylase from the genomic DNA library of Paenibacillus sp. was identified and characterized. The amylase gene designated amy1 was shown to consist of 1,980 bp and shared sequence identity towards α-amylase genes from other Bacillus sp. The deduced amino acid sequence for Amy1 indicated 80 % sequence identity with other Bacillus strains. Heterologous expression of recombinant Amy1 in Escherichia coli BL21(DE3) facilitated the recovery of this protein in soluble form. Enzyme kinetic data revealed Amy1 to have a K m of 23.83 mg/mL and K cat of 48.74 min(-1) and K cat /K m of 2 min(-1) mg(-1) mL(-1) for starch. The activity of this protein was found to be enhanced by Mn(2+), and furthermore, Amy1 remained active at a broad pH range (4-10) and temperature (30-90 °C). The ability of Amy1 to act on food waste under broad temperature and pH conditions, together with its ability to produce simple sugars, shows many advantages for further application in the food industry.

Deletion of an architectural unit, leucyl aminopeptidase (SCO2179), in Streptomyces coelicolor increases actinorhodin production and sporulation

Several reports state that three architectural units, including integration host factor, leucyl aminopeptidase (PepA), and purine regulator, are involved in transcriptional process with RNA polymerase in Escherichia coli. Similarly, Streptomyces species possess the same structural units. We previously identified a protein, Streptomyces integration host factor (sIHF), involved in antibiotic production and sporulation. Subsequently, the function of PepA (SCO2179) was examined in detail. PepA is highly conserved among various Streptomyces spp., but it has not yet been characterized in Streptomyces coelicolor. While it is annotated as a putative leucyl aminopeptidase because it contains a peptidase M17 superfamily domain, this protein did not exhibit leucyl aminopeptidase activity. SCO2179 deletion mutant showed increased actinorhodin production and sporulation, as well as more distinct physiological differences, particularly when cultured on N-acetylglucosamine (GlcNAc) minimal media. The results of two-dimensional gel analysis and reverse transcription PCR showed that the SCO2179 deletion increased protein and mRNA levels of ftsZ, ssgA, and actinorhodin (ACT)-related genes such as actII-ORF4, resulting in increased actinorhodin production and spore formation in minimal media containing GlcNAc.

Transcriptomic study for screening genes involved in the oxidative bioconversions of Streptomyces avermitilis

Streptomyces avermitilis is a well known organism producing avermectin antibiotics, and has been utilized as an industrial host for oxidation bioconversion processes. Recently, gene screening strategies related to bioconversions have received much focus, as attempts are made to optimize oxidation and biodegradation pathways to maximize yield and productivity. Here, we have demonstrated the oxidative metabolisms of three molecules, daidzein, p-coumaric acid and mevastatin, where S. avermitilis converted each substrate to 3',4',7-trihydroxyisoflavone, caffeic acid and hydroxyl-mevastatin to yield 9.3, 32.5 and 15.0 %, respectively. Microarray technology was exploited to investigate genome-wide analysis of gene expression changes, which were induced upon the addition of each substrate. Cytochrome P450 hydroxylases (pteC, cyp28 and olmB), diooxygenases (xylE, cdo1 and putatives) and LuxAB-like oxygenase were identified. One of them, cyp28, was indeed a gene encoding P450 hydroxylase responsible for the oxidative reaction of daidzein. Furthermore, possible electron transfer chain (fdrC → pteE → pteC) supporting cytochrome P450 dependent hydroxylation of daidzein has been suggested based on the interpretation of expression profiles. The result provided a potential application of transcriptomic study on uncovering enzymes involved in oxidative bioconversions of S. avermitilis.

Frequency of developmental dysplasia of the hip in breech-presented Chinese neonates in Hong Kong

OBJECTIVES. To clarify the use of ultrasonography by determining the frequency of developmental dysplasia of the hip among breech-presented Chinese neonates in Hong Kong. DESIGN. Prospective case series. SETTING. Regional hospital, Hong Kong. PATIENTS. All breech-presented Chinese neonates born during January 2008 to June 2009 were included (except premature neonates). They were examined clinically from birth till the age of 1 year. Ultrasound of the hips was performed at the age of 2 weeks, and X-ray of the pelvis at the age of 1 year. RESULTS. A total of 209 breech-presented neonates were born during the study period; 110 neonates completed all necessary investigations and follow-up. Among the latter, there were three neonates with developmental dysplasia of the hip warranting treatment, which amounted to a frequency of 2.7%. CONCLUSION. Developmental dysplasia of the hip among breech-presented Chinese babies is only slightly less common than in corresponding populations in other regions in the world. Since early diagnosis is important, ultrasonography screening in high-risk cases such as those with breech presentation may be useful.

Spin dynamics of the S = 5/2 2D triangular antiferromagnet Ba3NbFe3Si2O14

We report pulse-field magnetization, ac susceptibility, and 100 GHz electron spin resonance (ESR) measurements on the S = 5/2 two-dimensional triangular compound Ba3NbFe3Si2O14 with the Néel temperature T(N) = 26 K. The magnetization curve shows an almost linear increase up to 60 T with no indication of a one-third magnetization plateau. An unusually large frequency dependence of the ac susceptibility in the temperature range of T = 20-100 K reveals a spin-glass behavior or superparamagnetism, signaling the presence of frustration-related slow magnetic fluctuations. The temperature dependence of the ESR linewidth exhibits two distinct critical regimes; (i) ΔH(pp)(T) is proportional to (T-T(N))(-p) with the exponent p = 0.2(1)-0.2(3) for temperatures above 27 K, and (ii) ΔH(pp)(T) is proportional to (T-T*)(-p) with T* = 12 K and p = 0.8(1)-0.8(4) for temperatures between 12 and 27 K. This is interpreted as indicating a dimensional crossover of magnetic interactions and the persistence of short-range correlations with a helically ordered state.

Engineering of daidzein 3'-hydroxylase P450 enzyme into catalytically self-sufficient cytochrome P450

A cytochrome P450 (CYP) enzyme, 3’-daidzein hydroxylase, CYP105D7 (3’-DH), responsible for daidzein hydroxylation at the 3’-position, was recently reported. CYP105D7 (3’-DH) is a class I type of CYP that requires electrons provided through electron transfer proteins such as ferredoxin and ferredoxin reductase. Presently, we constructed an artificial CYP in order to develop a reaction host for the production of a hydroxylated product. Fusion-mediated construction with the reductase domain from self-sufficient CYP102D1 was done to increase electron transfer efficiency and coupling with the oxidative process. An artificial self-sufficient daidzein hydroxylase (3’-ASDH) displayed distinct spectral properties of both flavoprotein and CYP. The fusion enzyme catalyzed hydroxylation of daidzein more efficiently, with a k_cat/K_m value of 16.8 μM^-1 min^-1, which was about 24-fold higher than that of the 3’-DH-camA/B reconstituted enzyme. Finally, a recombinant Streptomyces avermitilis host for the expression of 3’-ASDH and production of the hydroxylated product was developed. The conversion that was attained (34.6%) was 5.2-fold higher than that of the wild-type.

Cloning, expression and characterization of CYP102D1, a self-sufficient P450 monooxygenase from Streptomyces avermitilis

Among 33 cytochrome P450s (CYPs) of Streptomyces avermitilis, CYP102D1 encoded by the sav575 gene is naturally a unique and self-sufficient CYP. Since the native cyp102D1 gene could not be expressed well in Escherichia coli, its expression was attempted using codon-optimized synthetic DNA. The gene was successfully overexpressed and the recombinant CYP102D1 was functionally active, showing a Soret peak at 450 nm in the reduced CO difference spectrum. FMN/FAD isolated from the reductase domain showed the same fluorescence in thin layer chromatography separation as the authentic standards. Characterization of the substrate specificity of CYP102D1 based on NADPH oxidation rate revealed that it catalysed the oxidation of saturated and unsaturated fatty acids with very good regioselectivity, similar to other CYP102A families depending on NADPH supply. In particular, CYP102D1 catalysed the rapid oxidation of myristoleic acid with a k(cat)/K(m) value of 453.4 ± 181.5 μM(-1)·min(-1). Homology models of CYP102D1 based on other members of the CYP102A family allowed us to alter substrate specificity to aromatic compounds such as daidzein. Interestingly, replacement of F96V/M246I in the active site increased catalytic activity for daidzein with a k(cat)/K(m) value of 100.9 ± 10.4 μM(-1)·min(-1) (15-fold).

Comparison of bolus transit patterns identified by esophageal impedance to barium esophagram in patients with dysphagia

Bolus transit through the esophagus has not been validated by videoesophagram in patients with dysphagia and changes in impedance with abnormal barium transit have not been described in those patients. The aim of this study was to compare esophageal impedance findings with barium esophagram measurements in patients with dysphagia. The consecutive patients with dysphagia underwent conventional multichannel esophageal impedance manometry, after which a barium videoesophagram was performed simultaneously with multichannel esophageal impedance manometry using a mean of three swallows of barium. Esophageal emptying patterns shown in the esophagogram were classified by the degree of intraesophageal stasis and presence of intraesophageal reflux. Bolus transit patterns in impedance were classified as complete and incomplete transit. Sixteen patients (M : F = 8 : 8, mean age, 47 years) were enrolled. Their manometric diagnosis were normal (n= 6), ineffective esophageal motility (n= 1), diffuse esophageal spasm (DES; n= 2), and achalasia (n= 7). Sixty-three swallows were analyzed. According to impedance analysis, 21/22 swallows with normal barium emptying showed complete transit (96%) and 31/32 swallows with severe stasis showed incomplete transit (97%). Nine swallows with mild stasis showed either complete or incomplete transit patterns in impedance. Swallows with mild barium stasis and complete transit in impedance were observed in patients who had received treatment (two patients with achalasia with history of esophageal balloonplasty and a patient with DES after nifedipine administration). Impedance reflected severe stasis with retrograde barium movement and described typical bolus transit patterns in patients with achalasia and DES. In conclusion, impedance-barium esophagram concordance is high for swallows with normal esophageal emptying and for severe barium stasis in patients with dysphagia.

Novel iron-sulfur containing NADPH-reductase from Nocardia farcinica IFM10152 and fusion construction with CYP51 lanosterol demethylase

CYP51, a sterol 14α-demethylase, is one of the key enzymes involved in sterol biosynthesis and requires electrons transferred from its redox partners. A unique CYP51 from Nocardia farcinica IFM10152 forms a distinct cluster with iron-sulfur containing NADPH-P450 reductase (FprD) downstream of CYP51. Previously, sequence alignment of nine reductases from N. farcinica revealed that FprC, FprD, and FprH have an additional sequence at their N-termini that has very high identity with iron-sulfur clustered ferredoxin G (FdxG). To construct an artificial self-sufficient cytochrome P450 monooxygenase (CYP) with only FprD, CYP51, and iron-sulfur containing FprD were fused together with designed linker sequences. CYP51-FprD fusion enzymes showed distinct spectral properties of both flavoprotein and CYP. CYP51-FprD F1 and F2 in recombinant Escherichia coli BL21(DE3) catalyzed demethylation of lanosterol more efficiently, with k(cat) /K(m) values of 96.91 and 105.79 nmol/min/nmol, respectively, which are about 35-fold higher compared to those of CYP51 and FprD alone.

Magnetic phase diagram of multiferroic MnWO4 probed by ultrasound

The magnetic phase diagram of multiferroic MnWO(4) is studied in magnetic fields up to 60 T using sound velocity and sound attenuation measurements. Anomalies are observed at temperatures T(N1) = 7.6 K, T(N2) = 12.6 K and T(N3) = 13.6 K that separate commensurate antiferromagnetic (AF1) to helical AF2 and commensurate AF3 to paramagnetic phases, respectively. The anomalies are significantly different and shed light on the spin-phonon coupling and evolution of the various order parameters in this multiferroic material. For temperatures below T(N2) pronounced field hysteresis effects are also observed in the sound velocity, indicating field-induced transformations. In the temperature dependence of the attenuation we observe anomalies distinctively different from the usual maxima related to relaxation effects. They are attributed to the combination of dispersion effects due to domain walls and the discontinuously changing sound velocity. In total, six different magnetic phases, at various temperatures and fields including a novel high-field phase, are revealed and analyzed.

Factors affecting mortality in Hong Kong patients with upper limb necrotising fasciitis

OBJECTIVE

To identify predictive factors for mortality of patients with upper limb necrotising fasciitis.

DESIGN

Retrospective study.

SETTING

Six hospitals in Hong Kong.

PATIENTS

Clinical records of 29 patients treated in the hospitals were traced and analysed.

MAIN OUTCOME MEASURES

Possible predictive factors for mortality as evaluated by application of Fisher's test.

RESULTS

Overall mortality was 28%. Digital infections conferred a lower mortality, but progressive necrosis necessitated amputation. Vibrio vulnificus was the commonest organism identified in association with marine injury and in patients with cirrhosis. Prognostic indicators with decreasing significance include deranged renal and liver function, thrombocytopaenia, proximal involvement (elbow or above) initially, and presence of hypotension upon admission.

CONCLUSION

With a P value of less than 0.05, deranged renal and liver function, thrombocytopaenia, initial proximal involvement, and hypotension on admission were predictors of mortality in necrotising fasciitis affecting the upper limbs. The ALERTS (Abnormal Liver function, Extent of infection, Renal impairment, Thrombocytopenia, and Shock) score with a cutoff of 3 appeared to predict mortality.

Guinea pig cytomegalovirus GP84 is a functional homolog of the human cytomegalovirus (HCMV) UL84 gene that can complement for the loss of UL84 in a chimeric HCMV

The guinea pig cytomegalovirus (GPCMV) co-linear gene and potential functional homolog of HCMV UL84 (GP84) was investigated. The GP84 gene had delayed early transcription kinetics and transient expression studies of GP84 protein (pGP84) demonstrated that it targeted the nucleus and co-localized with the viral DNA polymerase accessory protein as described for HCMV pUL84. Additionally, pGP84 exhibited a transdominant inhibitory effect on viral growth as described for HCMV. The inhibitory domain could be localized to a minimal peptide sequence of 99 aa. Knockout of GP84 generated virus with greatly impaired growth kinetics. Lastly, the GP84 ORF was capable of complementing for the loss of the UL84 coding sequence in a chimeric HCMV. Based on this research and previous studies we conclude that GPCMV is similar to HCMV by encoding single copy co-linear functional homologs of HCMV UL82 (pp71), UL83 (pp65) and UL84 genes.

Efficacy of assessment in fetal behaviour by four dimensional ultrasonography

This study was conducted to examine the behaviour and facial expressions of the fetus after birth by 4-dimensional (4-D) ultrasonography, and the association of the biophysical profile (BPP) with the Doppler scale. A total of 40 singleton pregnancies were included. All 4-D ultrasonographies were performed using the Accuvix XQ (Medison Co. Ltd, Seoul, Republic of Korea). The BPP and Doppler were performed on gravidas using 2-D ultrasonography. We recorded the newborn while awake no later than 48 h after delivery. The most frequent movement in fetuses and newborn was yawning and isolated arm movements, respectively. Sucking, swallowing (r = 0.78) and isolated limb movements (r = 0.72) in fetuses as observed by 4-D ultrasonography had a relationship with isolated limb movements in the newborn. Because of the limitation of ultrasonography, an overall comparison could not be made. There was a high correlation between sucking, swallowing, and isolated limb movements in fetuses and newborn.

Accelerated photobleaching of a cyanine dye in the presence of a ternary target DNA, PNA probe, dye catalytic complex: a molecular diagnostic

In many settings, molecular testing is needed but unavailable due to complexity and cost. Simple, rapid, and specific DNA detection technologies would provide important alternatives to existing detection methods. Here we report a novel, rapid nucleic acid detection method based on the accelerated photobleaching of the light-sensitive cyanine dye, 3,3'-diethylthiacarbocyanine iodide (DiSC(2)(3) I(-)), in the presence of a target genomic DNA and a complementary peptide nucleic acid (PNA) probe. On the basis of the UV-vis, circular dichroism, and fluorescence spectra of DiSC(2)(3) with PNA-DNA oligomer duplexes and on characterization of a product of photolysis of DiSC(2)(3) I(-), a possible reaction mechanism is proposed. We propose that (1) a novel complex forms between dye, PNA, and DNA, (2) this complex functions as a photosensitizer producing (1)O(2), and (3) the (1)O(2) produced promotes photobleaching of dye molecules in the mixture. Similar cyanine dyes (DiSC(3)(3), DiSC(4)(3), DiSC(5)(3), and DiSC(py)(3)) interact with preformed PNA-DNA oligomer duplexes but do not demonstrate an equivalent accelerated photobleaching effect in the presence of PNA and target genomic DNA. The feasibility of developing molecular diagnostic assays based on the accelerated photobleaching (the smartDNA assay) that results from the novel complex formed between DiSC(2)(3) and PNA-DNA is under way.

77Se and 63Cu NMR studies of the electronic correlations in CuxTiSe2 (x = 0.05, 0.07)

We report a (77)Se and (63)Cu nuclear magnetic resonance (NMR) investigation on the charge-density-wave (CDW) superconductor Cu(x)TiSe(2) (x = 0.05 and 0.07). At high magnetic fields where superconductivity is suppressed, the temperature dependence of (77)Se and (63)Cu spin-lattice relaxation rates 1/T(1) follow a linear relation. The slope of (77)Se 1/T(1) versus T increases with the Cu doping. This can be described by a modified Korringa relation which suggests the significance of electronic correlations and the Se 4p- and Ti 3d-band contribution to the density of states at the Fermi level in the studied compounds.

Bone morphogenetic protein 4 stimulates attachment of neurospheres and astrogenesis of neural stem cells in neurospheres via phosphatidylinositol 3 kinase-mediated upregulation of N-cadherin

The neurosphere culture system is useful for expanding neural stem cells (NSCs) without affecting self-renewal potential and multipotency. However, the extrinsic signals that affect the formation or dissociation of neurospheres are poorly understood. Here, we found that bone morphogenetic protein 4 (BMP4) induced the attachment of neurospheres, astrocytic differentiation, and migration of neurosphere NSCs. These outcomes were accompanied by Akt activation and upregulation of the adhesion molecule, N-cadherin. A phosphatidylinositol 3 kinase (PI3 kinase) inhibitor (LY294002) blocked attachment of neurosphere, astrocytic differentiation, migration, and N-cadherin upregulation of neurosphre NSCs. The PI3 kinase-Akt pathway appeared to selectively mediate the effects of BMP4, as neurosphere attachment was unaffected by MEK inhibitors (PD98059 and U0126). Importantly, a neutralizing N-cadherin antibody inhibited BMP4-induced neurosphere attachment, astrocytic differentiation, and migration of neurosphere NSCs. Together, these findings show that BMP4-induced attachment of neurospheres is related to the astrocytic differentiation of these cells and that these effects are attributable, at least in part, to PI3 kinase-Akt pathway-dependent induction of N-cadherin.

Percutaneous endoscopic thoracic discectomy; transforaminal approach

INTRODUCTION

Because of the increasing use of magnetic resonance imaging (MRI), thoracic soft disc herniations are being easily detected in the early stages. To avoid a high morbidity rate and other complications that are associated with the conventional approach, the authors have applied a percutaneous endoscopic technique.

METHODS

From May 2001 to July 2007, fourteen patients with soft lateral or central thoracic disc herniation (TDH) underwent percutaneous endoscopic thoracic discectomy. Under local anesthesia with intravenous sedation, the authors removed the herniated disc through the thoracic intervertebral foramen after performing a foraminoplasty, which is the enlargement of the foramen by cutting the lateral and inferior part of the superior facet with a round cutter. The clinical outcome was evaluated using the visual analogue scale (VAS) and Oswestry disability index (ODI). RESULTS Six patients were male and eight were female, aged 21-75 years (mean: 48.1 years). Mean follow-up period was 60.2 months (15-89 months), mean operative time was 61 min. The mean VAS improved from 6.5 to 3.0 for back pain and 5.8 to 2.5 for leg pain at the final follow-up. The mean ODI scores also improved from 58.1 before surgery to 24.5 at the final follow-up. Conversion to an open procedure was not required for any of the patients.

DISCUSSION

As it has been proven to lessen the morbidity rate, this percutaneous endoscopic thoracic discectomy (PETD) technique for symptomatic soft TDH is a safe and effective method that provides a direct route to the lesion under local anesthesia.

Regioselective hydroxylation of daidzein using P450 (CYP105D7) from Streptomyces avermitilis MA4680

Regiospecific 3'-hydroxylation reaction of daidzein was performed with CYP105D7 from Streptomyces avermitilis MA4680 expressed in Escherichia coli. The apparent K(m) and k(cat) values of CYP105D7 for daidzein were 21.83 +/- 6.3 microM and 15.01 +/- 0.6 min(-1) in the presence of 1 microM of CYP105D7, putidaredoxin (CamB) and putidaredoxin reductase (CamA), respectively. When CYP105D7 was expressed in S. avermitilis MA4680, its cytochrome P450 activity was confirmed by the CO-difference spectra at 450 nm using the whole cell extract. When the whole-cell reaction for the 3'-hydroxylation reaction of daidzein was carried out with 100 microM of daidzein in 100 mM of phosphate buffer (pH 7.5), the recombinant S. avermitilis grown in R2YE media overexpressing CYP105D7 and ferredoxin FdxH (SAV7470) showed a 3.6-fold higher conversion yield (24%) than the corresponding wild type cell (6.7%). In a 7 L (working volume 3 L) jar fermentor, the recombinants S. avermitilis grown in R2YE media produced 112.5 mg of 7,3',4'-trihydroxyisoflavone (i.e., 29.5% conversion yield) from 381 mg of daidzein in 15 h.

Regioselective hydroxylation of isoflavones by Streptomyces avermitilis MA-4680

Screening of bacterial whole cells was performed for regioselective hydroxylation of daidzein and genistein. Among the strains examined, Streptomyces avermitilis MA-4680 showed high ortho-dihydroxylation activity to produce 3',4',7-trihydroxyisoflavone and 3',4',5,7-tetrahydroxyisoflavone from daidzein (4',7-dihydroxyisoflavone) and genistein (4',5,7-trihydroxyisoflavone), respectively. Using 100 mg cells (wet wt.) and 1% (v/v) Triton X100 in 1 ml of total reaction volume, where 100 microl of the substrate solution (0.5 mM in 10% (v/v) mixed solvent of DMSO:MeOH = 3:7) was added to 900 microl of potassium phosphate buffer (100 mM, pH 7.2), a 16% molar conversion yield of 3',4',7-trihydroxyisoflavone was obtained from 0.5 mM daidzein after 24 h of reaction time at 28 degrees C and 200 rpm. Ketoconazole significantly (ca. 90%) inhibited the ortho-hydroxylation activity of daidzein, suggesting that cytochrome P450 enzymes putatively play roles in regiospecific daidzein hydroxylation. The analysis of the reaction products was determined by gas chromatography/mass spectrometry (GC/MS) and (1)H NMR.

Observation of the sweating in lipstick by scanning electron microscopy

The relationship between the wax matrix in lipstick and sweating has been investigated by observing the change of size and shape of the wax matrix due to sweating by Scanning Electron Microscopy (SEM). For observation by SEM, a lipstick sample was frozen in liquid nitrogen. The oil in the lipstick was then extracted in cold isopropanol (-70 degrees C) for 1-3 days. After the isopropanol was evaporated, the sample was sputtered with gold and examined by SEM. The change of wax matrix underneath the surface from fine, uniform structure to coarse, nonuniform structure resulted from the caking of surrounding wax matrix. The oil underneath the surface migrated to the surface of lipstick with sweating; consequently the wax matrix in that region was rearranged into the coarse matrix. In case of flamed lipstick, sweating was delayed and the wax matrix was much coarser than that of the unflamed one. The larger wax matrix at the surface region was good for including oil. The effect of molding temperature on sweating was also studied. As the molding temperature rose, sweating was greatly reduced and the size of the wax matrix increased. It was found that sweating was influenced by the compatibility of wax and oil. A formula consisting of wax and oil that have good compatibility has a tendency to reduce sweating and increase the size of the wax matrix. When pigments were added to wax and oil, the size of the wax matrix was changed, but in all cases sweating was increased due to the weakening of the binding force between wax and oil. On observing the thick membrane of wax at the surface of lipstick a month after molding it was also found that sweating was influenced by ageing. In conclusion, the structure of the wax matrix at the surface region of lipstick was changed with the process of flaming, molding temperature, compatibility of wax and oil, addition of pigment, and ageing. In most cases, as the size of the wax matrix was increased, sweating was reduced and delayed.

Successful endoscopic hemoclipping of an esophageal perforation

We describe a case of esophageal perforation that resulted from a fishbone. A 71-year-old man had had a fishbone impacted in the lower esophagus for 2 days. At presentation, the bone was dislodged at endoscopy; one round opening in a deep ulceration was detected when the fishbone was removed. The perforation was closed by endoscopic hemoclipping, after the removal of the fishbone. A thoracic computed tomography revealed air around the esophagus, aorta and bronchus and the presence of a pleural effusion. These findings suggested mediastinal emphysema and mediastinitis due to the esophageal perforation after the removal of the fishbone. Esophagography revealed a focal esophageal defect and linear contrast leakage at the distal esophagus. The mediastinal emphysema and pleural effusion successfully resolved after the endoscopic hemoclip application and conservative management of the perforation.

Degradation of atrazine by modified stepwise-Fenton's processes

The removal of atrazine (ATZ) by stepwise Fenton's processes (stepwise-FP) was studied and the system models were developed through the examination of reaction kinetics. The study compared the performance of the removal of ATZ by conventional FP with stepwise-FP, where the total dose of H(2)O(2) was split and inputted into the system at different times and/or quantities. The performance of stepwise-FP was found to be better than that of conventional FP. This was probably due to the minimization of the peak concentration of H(2)O(2) in the solution, which reduced the probability that valuable H(2)O(2) and hydroxyl radicals would be consumed in forming weaker radicals. The reaction kinetics of the decay of ATZ in stepwise-FP was found to be a two-stage process; and in each stage, fast decay followed by stagnant decay was observed. Two characterized constants (the initial decay rate and the oxidative capacity) were introduced and were found to be useful in quantifying the stepwise-FP. The models for predicting stepwise-FP with respect to different dosing times and/or asymmetrical doses were developed, and were found to be very useful for evaluating the system performance and/or for process design.

Serotonin transporter gene polymorphism and irritable bowel syndrome

Polymorphisms in the promoter region of the serotonin reuptake transporter (SERT) gene may underlie the disturbance in gut function in patients with irritable bowel syndrome (IBS). Association studies of SERT polymorphisms and IBS have shown diverse results among different countries, which might be due to racial and subject composition differences. The aim of this study was to assess the potential association between SERT polymorphisms and IBS in Koreans. A total of 190 IBS patients, who met the Rome II criteria, and 437 healthy controls were subjected to genotyping. SERT polymorphisms differed in the IBS and control groups (P = 0.014). The SERT deletion/deletion genotype occurred with greater frequency in the diarrhoea-predominant IBS group than in the controls. A strong genotypic association was observed between the SERT deletion/deletion genotype and diarrhoea-predominant IBS (P = 0.012). None of the clinical symptoms analysed was significantly associated with the SERT genotypes. The frequency of the SERT insertion/insertion genotype was much lower than that of the other two genotypes. A significant association was observed between the SERT polymorphism and IBS, especially diarrhoea-predominant IBS, suggesting that the SERT gene is a potential candidate gene involved in IBS in Korea.

Anomalous electronic Raman scattering in NaxCoO2.yH2O

Raman scattering experiments on NaxCoO2.yH2O single crystals show a broad electronic continuum with a pronounced peak around 100 cm(-1) and a cutoff at approximately 560 cm(-1) over a wide range of doping levels. The electronic Raman spectra in superconducting and nonsuperconducting samples are similar at room temperature, but evolve in markedly different ways with decreasing temperature. For superconducting samples, the low-energy spectral weight is depleted upon cooling below T* approximately 150 K, indicating the opening of a pseudogap that is not present in nonsuperconducting materials. Weak additional phonon modes observed below T* suggest that the pseudogap is associated with charge ordering.

Primary colon lymphoma in Korea: a KASID (Korean Association for the Study of Intestinal Diseases) Study

Although almost all primary colorectal lymphomas are of B-cell lineage in Western countries, primary colorectal T-cell lymphomas are not uncommon in the East. The aim of this study was to review the clinical characteristics and treatment outcomes of primary colorectal lymphomas, with special emphasis on the differences between T-cell and B-cell lymphomas. Ninety-five cases of primary colorectal lymphomas that satisfied Dawson's criteria were identified from the clinical databases of 13 university hospitals in Korea. The mean age at the time of presentation was 51.1 years and the male:female ratio was 64:31. The clinical information, including endoscopic and histological characteristics, was retrospectively analyzed. Of the primary colorectal lymphomas, 78 cases (82.1%) were of B-lineage and 17 cases (17.9%) were of T-cell lineage. Patients with T-cell lymphomas presented at a younger age than patients with B-cell lymphomas (42.8 vs 52.9 years, respectively; P = 0.016). The most common presenting symptom was abdominal pain (87.1%) for B-cell lymphomas, whereas hematochezia or night fever was more common for T-cell lymphomas (52.9% and 35.3%, respectively). The most common endoscopic type was fungating mass (54.0%) for B-cell lymphomas and ulcerative/ulcero-infiltrative lesions (80.0%) for T-cell lymphomas. Intussusception was more common in B-cell lymphomas than in T-cell lymphomas (30.8% vs 5.9%, respectively; P = 0.035), but perforation was more common in T-cell lymphomas than in B-cell lymphomas (23.5% vs 3.8%, respectively; P = 0.005). The prognosis was significantly worse for T-cell lymphomas than for B-cell lymphomas (P = 0.002). Primary colorectal T-cell lymphomas are characterized by multifocal ulcerative lesions in relatively young patients, a high rate of hematochezia, fever, or perforation, and a poor prognosis even for cases of localized disease.

Endoscopic hemoclipping using a transparent cap in technically difficult cases

BACKGROUND AND STUDY AIMS

Technical difficulties have been experienced in endoscopic hemoclipping on the posterior wall of the body of the stomach because the angle of approach is tangential. It has been suggested that the use of a transparent cap on the tip of the endoscope could help to solve this problem. The purpose of this study was to examine the efficacy of endoscopic hemoclipping using a transparent cap over the tip of the endoscope.

PATIENTS AND METHODS

A total of 74 patients with a bleeding peptic ulcer or stigmata of recent hemorrhage underwent endoscopic hemoclipping. Technical difficulty in hemoclipping was experienced in 18 patients and the transparent cap was used in these cases. We therefore conducted a nonrandomized prospective study to compare bleeding control with the hemoclip with and without the aid of a transparent cap.

RESULTS

There were no statistically significant differences between the patients treated with the cap and those treated without the cap with regard to the initial hemostasis rate (94.4 % vs. 91.1 %), the rebleeding rate (11.7 % vs. 11.8 %), or the permanent hemostasis rate (94.4 % vs. 96.4 %).

CONCLUSIONS

Although there was no statistically significant difference between patients treated with or without a transparent cap, hemoclipping with the aid of the cap made it possible to clip a lesion too tangential to be clipped without it. However, this study did not compare conventional hemoclipping with hemoclipping using a cap because the cap was only used in cases in which conventional clipping had failed.

Two cases of steakhouse syndrome associated with nutcracker esophagus

The most common type of esophageal food-related foreign body is the meat bolus, which is frequently associated with underlying esophageal stenosis. Herein, we report two cases of meat bolus impaction associated with nutcracker esophagus. In the first case, the 63-year-old male patient had chest discomfort and swallowing difficulty after ingestion of butcher's meat. In the second case, the 55-year-old male patient had complained of swallowing difficulty after ingestion of chicken. In both cases, no pathologic findings were observed endoscopically after removal of the esophageal meat bolus. We performed esophageal manometry, which showed very high amplitudes of esophageal pressure in the mid- and distal esophagus. These findings were consistent with nutcracker esophagus. These cases show that esophageal motility disorder may be the cause of esophageal foreign body impaction, and esophageal manometry should be performed for evaluation of the cause of foreign body, especially in an endoscopically normal patient.

Structure and enzymology of Delta5-3-ketosteroid isomerase

The three-dimensional structures of Delta5-3-ketosteroid isomerases from two different bacterial species have been determined. The structures reveal an unusually apolar active site, in which each of several competitive inhibitors of the enzyme are held by two hydrogen bonds with the general acids Tyr14 and Asp99, and by hydrophobic interactions. The hydrogen bond between the Tyr14 hydroxyl and the C3 oxyanion of a transition-state analog is a low-barrier hydrogen bond, as indicated by a highly deshielded nuclear magnetic resonance. Structural and other biochemical studies have enabled the proposal of a detailed catalytic mechanism for Delta5-3-ketosteroid isomerase and provided a major thrust towards understanding the mechanism not only in chemical terms but also in energetics terms.

Evidence for an unconventional magnetic instability in the spin-tetrahedra system Cu(2)Te(2)O(5)Br(2)

Thermodynamic experiments as well as Raman scattering have been used to study the magnetic instabilities in the spin-tetrahedra systems Cu(2)Te(2)O(5)X(2), X = Cl and Br. While the phase transition observed in the Cl system at T(N) = 18.2 K is consistent with 3D antiferromagnetic ordering, the phase transition at T(o) = 11.4 K in the Br system has several unusual features. We propose an explanation in terms of weakly coupled tetrahedra with a singlet-triplet gap and low-lying singlets.

Maintenance of alpha-helical structures by phenyl rings in the active-site tyrosine triad contributes to catalysis and stability of ketosteroid isomerase from Pseudomonas putida biotype B

Ketosteroid isomerase (KSI) from Pseudomonas putida biotype B is a homodimeric enzyme catalyzing an allylic rearrangement of Delta5-3-ketosteroids at rates comparable with the diffusion-controlled limit. The tyrosine triad (Tyr14.Tyr55.Tyr30) forming a hydrogen-bond network in the apolar active site of KSI has been characterized in an effort to identify the roles of the phenyl rings in catalysis, stability, and unfolding of the enzyme. The replacement of Tyr14, a catalytic residue, with serine resulted in a 33-fold decrease of kcat, while the replacements of Tyr30 and Tyr55 with serine decreased kcat by 4- and 51-fold, respectively. The large decrease of kcat for Y55S could be due to the structural perturbation of alpha-helix A3, which results in the reorientation of the active-site residues as judged by the crystal structure of Y55S determined at 2.2 A resolution. Consistent with the analysis of the Y55S crystal structure, the far-UV circular dichroism spectra of Y14S, Y30S, and Y55S indicated that the elimination of the phenyl ring of the tyrosine reduced significantly the content of alpha-helices. Urea-induced equilibrium unfolding experiments revealed that the DeltaG(U)H2O values of Y14S, Y30S, and Y55S were significantly decreased by 11.9, 13.7, and 9.5 kcal/mol, respectively, as compared with that of the wild type. A characterization of the unfolding kinetics based on PhiU-value analysis indicates that the interactions mediated by the tyrosine triad in the native state are very resistant to unfolding. Taken together, our results demonstrate that the internal packing by the phenyl rings in the active-site tyrosine triad contributes to the conformational stability and catalytic activity of KSI by maintaining the structural integrity of the alpha-helices.

[2,13-Bis(acetamido)-5,16-dimethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane]copper(II) dichloride octahydrate

The title compound, [Cu(C(24)H(46)N(6)O(2))]Cl(2).8H(2)O, contains a centrosymmetric cation, with the anions and water molecules on general sites. The coordination geometry around the Cu(II) ion is an axially elongated octahedron, with Cu-N distances of 2.0448 (17) and 2.0847 (17) A, and a Cu-O1 distance of 2.3138 (16) A.

The role of Tyr248 probed by mutant bovine carboxypeptidase A: insight into the catalytic mechanism of carboxypeptidase A

We have investigated the function of Tyr248 using bovine wild-type CPA and its Y248F and Y248A mutants to find that the K(M) values were increased by 4.5-11-fold and the k(cat) values were reduced by 4.5-10.7-fold by the replacement of Tyr248 with Phe for the hydrolysis of hippuryl-L-Phe (HPA) and N-[3-(2-furyl)acryloyl]-Phe-Phe (FAPP), respectively. In the case of O-(trans-p-chlorocinnamoyl)-L-beta-phenyllactate (ClCPL), an ester substrate, the K(M) value was increased by 2.5-fold, and the k(cat) was reduced by 20-fold. The replacement of Tyr248 with Ala decreased the k(cat) values by about 18- and 237-fold for HPA and ClCPL, respectively, demonstrating that the aromatic ring of Tyr248 plays a critical role in the enzymic reaction. The increases of the K(M) values were only 6- and 5-fold for HPA and ClCPL, respectively. Thus, the present study indicates clearly that Tyr248 plays an important role not only in the binding of substrate but also in the enzymic hydrolysis. The kinetic results may be rationalized by the proposition that the phenolic hydroxyl of Tyr248 forms a hydrogen bond with the zinc-bound water molecule, causing further activation of the water molecule by reducing its pK(a) value. The pH dependency study of k(cat) values and the solvent isotope effects also support the proposition. A unified catalytic mechanism is proposed that can account for the different kinetic behavior observed in the CPA-catalyzed hydrolysis of peptide and ester substrates.

Pseudoreversion of the catalytic activity of Y14F by the additional substitution(s) of tyrosine with phenylalanine in the hydrogen bond network of delta 5-3-ketosteroid isomerase from Pseudomonas putida biotype B

Delta5-3-ketosteroid isomerase (KSI) from Pseudomonas putida Biotype B catalyzes the allylic isomerization of Delta5-3-ketosteroids to their conjugated Delta4-isomers via a dienolate intermediate. Two electrophilic catalysts, Tyr-14 and Asp-99, are involved in a hydrogen bond network that comprises Asp-99 Odelta2...O of Wat504...Tyr-14 Oeta...Tyr-55 Oeta.Tyr-30 Oeta in the active site of P. putida KSI. Even though neither Tyr-30 nor Tyr-55 plays an essential role in catalysis by the KSI, the catalytic activity of Y14F could be increased ca. 26-51-fold by the additional Y30F and/or Y55F mutation in the hydrogen bond network. To identify the structural basis for the pseudoreversion in the KSI, crystal structures of Y14F and Y14F/Y30F/Y55F have been determined at 1.8 and 2.0 A resolution, respectively. Comparisons of the two structures near the catalytic center indicate that the hydrogen bond between Asp-99 Odelta2 and C3-O of the steroid, which is perturbed by the Y14F mutation, can be partially restored to that in the wild-type enzyme by the additional Y30F/Y55F mutations. The kinetic parameters of the tyrosine mutants with the additional D99N or D99L mutation also support the idea that Asp-99 contributes to catalysis more efficiently in Y14F/Y30F/Y55F than in Y14F. In contrast to the catalytic mechanism of Y14F, the C4 proton of the steroid substrate was found to be transferred to the C6 position in Y14F/Y30F/Y55F with little exchange of the substrate 4beta-proton with a solvent deuterium based on the reaction rate in D2O. Taken together, our findings strongly suggest that the improvement in the catalytic activity of Y14F by the additional Y30F/Y55F mutations is due to the changes in the structural integrity at the catalytic site and the resulting restoration of the proton-transfer mechanism in Y14F/Y30F/Y55F.