Probing the function of the invariant glutamyl residue 312 in spinach ferredoxin-NADP+ reductase

Ferredoxin-NADP+ reductase, the prototype of a large family of structurally related flavoenzymes, pairs single electrons carried by ferredoxin I and transfers them as a hydride to NADP+. Four mutants of the enzyme, in which Glu-312 was replaced with Asp, Gln, Leu, and Ala to probe the role of the residue charge, size, and polarity in the enzyme activity, have been heterologously expressed, purified, and characterized through steady-state, rapid kinetic studies, ligand-binding experiments, and three-dimensional structure determination by x-ray crystallography. The E312L mutant was the only one that was almost inactive (approximately 1%), whereas unexpectedly the E312A reductase was 10-100% active with the various acceptors tested. Rapid kinetic absorption spectroscopy studies demonstrated that flavin reduction by NADPH was impaired in the mutants. Furthermore, NADP(H) binding was partially perturbed. These functional and structural studies lead us to conclude that Glu-312 does not fulfil the role of proton donor during catalysis, but it is required for proper binding of the nicotinamide ring of NADP(H). In addition, its charge modulates the two one-electron redox potentials of the flavin to stabilize the semiquinone form.

On the active site of Old Yellow Enzyme. Role of histidine 191 and asparagine 194

Old Yellow Enzyme (OYE) binds phenolic ligands forming long wavelength (500-800 nm) charge-transfer complexes. The enzyme is reduced by NADPH, and oxygen, quinones, and alpha,beta-unsaturated aldehydes and ketones can act as electron acceptors to complete catalytic turnover. Solution of the crystal structure of OYE1 from brewer's bottom yeast (Fox, K. M., and Karplus, P. A. (1994) Structure 2, 1089-1105) made it possible to identify histidine 191 and asparagine 194 as amino acid residues that hydrogen-bond with the phenolic ligands, stabilizing the anionic form involved in charge-transfer interaction with the FMN prosthetic group. His-191 and Asn-194 are also predicted to interact with the nicotinamide ring of NADPH in the active site. Mutations of His-191 to Asn, Asn-194 to His, and a double mutation, H191N/N194H, were made of OYE1. It was not possible to isolate the N191H mutant enzyme, but the other two mutant forms had the expected effect on phenolic ligand binding, i.e. decreased binding affinity and decreased charge-transfer absorbance. Reduction of the H191N mutant enzyme by NADPH was similar to that of OYE1, but the reduction rate constant for NADH was greatly decreased. The double mutant enzyme had an increased rate constant for reduction by NADPH, but the reduction rate constant with NADH was lower by a factor of 15. The reactivity of OYE1 and the mutant enzymes with oxygen was similar, but the reactivity of 2-cyclohexenone was greatly decreased by the mutations. The crystal structures of the two mutant forms showed only minor changes from that of the wild type enzyme.

Expression of monocyte chemoattractant protein-1 in monocytes and effects of native and oxidized very low density lipoproteins

Monocyte chemoattractant protein-1 (MCP-1), a potent chemoattractant, is thought to play an important role in migration of monocytes into atherosclerotic lesions. The present study was designed to investigate the capacity of human peripheral blood monocytes to express MCP-1 and effects of native very low density lipoprotein (VLDL) and oxidized VLDL (OX-VLDL) on the expression. The total RNA was extracted from cultured monocytes, which were exposed to VLDL and OX-VLDL, and the media conditioned by monocytes were collected. MCP-1 mRNA expression was examined by Northern blot analysis. MCP-1 protein in conditioned media was determined by using sandwich ELISA. The results showed that monocytes can express MCP-1 after a 24 h incubation at 37 degrees C, and the expression was markedly increased by a exposure to OX-VLDL, whereas the expression was slightly increased when exposed to VLDL. It suggests that the capacity of monocytes to produce MCP-1 that recruits and activates circulating monocytes may be of considerable importance in atherogenesis, and oxidation of VLDL enhances its potential to promote atherogenesis.

Diagnosis of familial Mediterranean fever by a molecular genetics method

BACKGROUND

Familial Mediterranean fever is a recessively inherited disorder characterized by episodes of fever with abdominal pain, pleurisy, or arthritis. The familial Mediterranean fever gene, designated MEFV, was recently cloned, and at least three missense mutations (M6801, M694V, and V726A) that account for a large percentage of patients with this disease were identified.

OBJECTIVE

To establish a diagnostic test for familial Mediterranean fever.

DESIGN

Cross-sectional study of a convenience sample of patients attending familial Mediterranean fever clinics.

SETTING

Tertiary referral hospitals.

PATIENTS

107 patients with familial Mediterranean fever, their family members, and controls.

MEASUREMENTS

Mutations in the 107 samples were assessed by amplifying genomic DNA with use of primers that selectively amplify the normal or altered DNA sequence of the 3 MEFV mutations (amplification refractory mutation system [ARMS]). Mutations were independently assessed by automated sequencing of genomic DNA amplified by polymerase chain reaction to evaluate the sensitivity and specificity of the ARMS assay.

RESULTS

The ARMS assay correctly identified M6801, M694V, and V726A mutations in 82 persons with mutations documented by DNA sequencing (21 homozygotes, 2 compound heterozygotes, and 59 simple heterozygotes). Of 7 persons known from family studies to be noncarriers and 18 unrelated persons who were negative for these mutations by sequencing, none had MEFV mutations according to ARMS.

CONCLUSION

The ARMS assay is a rapid, cost-effective, and accurate method for detecting three common mutations in familial Mediterranean fever.

Identification of two Krüppel-related zinc finger genes (ZNF200 and ZNF210) from human chromosome 16p13.3

During the course of cloning the gene for familial Mediterranean fever (FMF), we identified a number of transcripts from a 275-kb genomic region on 16p13.3. Two of the transcripts were found to contain multiple C2H2-type zinc finger motifs in tandem arrays, indicating that they are members of the Krüppel-type family. One transcript was found to be an alternatively spliced form of a previously reported zinc finger gene, ZNF200. The other transcript, ZNF210, is 2017 bp and encodes an open reading frame of 504 aa. Northern blot analysis indicates that ZNF210 is expressed in all the tissues tested with the highest expression in heart, skeletal muscle, pancreas, prostate, ovary, and colon. On the other hand, the strongest expression of ZNF200 is in testis, with very low levels in all the other tissues tested. Sequence analysis reveals eight C2H2 zinc finger motifs at the C-terminus of ZNF210 and five in ZNF200. In addition, ZNF210 also possesses a Krüppel-associated box at its N-terminus, indicating that it might function as a transcription repressor. The intron-exon structures of both genes were determined and showed that ZNF210 has seven exons while the coding part of ZNF200 is distributed in four exons. The locations of ZNF200 and ZNF210 are 10 and 120 kb telomeric to the FMF gene, respectively.

An essential methionine residue involved in substrate binding by phosphofructokinases

An alignment of all PPi-dependent phosphofructokinases and all allosteric ATP-dependent PFKs shows relatively few residues that are fully conserved. One residue that is conserved is a methionine residue that appears from the crystal structure of Escherichia coli PFK to be interacting with fructose 6-P. Very conservative substitutions for this methionine with leucine or isoleucine by site-directed mutagenesis of E. coli ATP-PFK and Entamoeba histolytica PPi-PFK produced profound decreases either in the apparent affinity for fructose 6-P or in maximal velocity, or both. Methionine provides a highly specific interaction with fructose 6-P for binding and for transition state stabilization.

[Assessment of diagnostic result for medical image by receiver operating characteristic and forced choice]

Two methods for diagnostic image evaluation, the receiver operating characteristic (ROC) and the forced choice, are introduced in this paper. The concepts of ROC and forced choice are described firstly, then the experiment design consideration and data analysis are discussed.

[The relationship between hepatocellular carcinoma and hepatitis C virus infection in Guangxi, China]

OBJECTIVE

To study the significance of HCV infection as a risk factor for hepatocellular carcinoma (HCC) in Guangxi.

METHODS

Monoclonal antibodies against the core, NS3 and NS4 region of HCV, and anti-HBsAg antibody were used for immunohistochemical staining.

RESULTS

The frequency of HCV infection from regions with high, intermediate and low prevalence of HCC was 24/63(38.1%), 23/62 (37.1%) and 30/77(39.0%), respectively, while that of HBsAg was 84.1%, 83.8% and 84.4%, respectively. The overall positive rate of HCV infection was 77/202 (38.1%), and of HBV infection was 170/202 (84.2%).

CONCLUSION

While HBV infection frequently accompanies HCC, HCV infection is present in more than 1/3 of HCC. This is generally the case regardless of geographical difference in HCC prevalence.

Effect of oral aluminum and aluminum citrate on blood level and short-term tissue distribution of aluminum in the rat

Aluminum (Al) absorption seems to be very low, but many factors can enhance it in animals and humans. In the present study, we investigated the acute effect of Na citrate on Al absorption by monitoring Al levels in blood and several tissues. For this purpose, 18 Wistar male rats were divided into 3 groups: control, Al, and Al + Na citrate. After a 14-h fasting period, animals were dosed orally with deionized water, or 2 mmol Al chloride, or 2 mmol Al chloride plus 2 mmol Na citrate. Blood samples were taken before and 1, 2, 4, and 6 h after the gavage. Al concentrations in blood, liver, tibia, kidney, and intestinal wall were determined by ICP-OES. In the Al and Al + citrate groups, Al blood concentrations peaked at 1 h and 2 h with higher levels in the Al + citrate group. Al gavage resulted in an increase in Al level in intestinal wall, but not in the other investigated tissues. Simultaneous gavage of citrate with Al significantly increased its tissue levels in tibia, kidney, and in intestinal wall. Our data show clearly that Al as chloride can be absorbed, but not well retained by the organism tissues. Furthermore, the model used in the present study is appropriate for acute studies to investigate the effect of various compounds on Al absorption in the rat.

[The influence of vascular endothelial growth factor and its receptor on the growth of laryngeal cancer cell]

The function of VEGF in laryngeal carcinoma was studied by observing either the expressions of VEGF and its receptor flk-1 in laryngeal carcinoma, or the effect of anti-VEGF antibody and anti-VEGF receptor antibody on the growth of human laryngeal cancer cell line HEP-2 in vitro. The expression of VEGF and flt in the specimen of laryngeal carcinoma were determined by standardized immunohistochemistry (Elite ABC method). Anti-VEGF antibody and anti-VEGF receptor antibody were also added at various concentrations to the culture medium, respectively, and the growth of HEP-2 was measured by MTT assay. The immunohistochemical staining showed that the expressions of VEGF and flt were detected both in carcinoma cells and endothelial cells. The growth of HEP-2 cell line in vitro was suppressed when adding various concentration of anti-VEGF antibody and anti-VEGF receptor antibody to the culture medium. The laryngeal cancer cells can secret VEGF and there exists VEGF-binding site on laryngeal cancer cell. Both blockading VEGF with anti-VEGF antibody and blockading VEGF-binding site with anti-VEGF receptor antibody could inhibit HEP-2 growth.

Familial Mediterranean fever at the millennium. Clinical spectrum, ancient mutations, and a survey of 100 American referrals to the National Institutes of Health

Regarded as the most common and best understood of the hereditary periodic fever syndromes, familial Mediterranean fever (FMF) is a recessively inherited disease of episodic fever with some combination of severe abdominal pain, pleurisy, arthritis, and a characteristic ankle rash. The flares typically last for up to 3 days at a time, and most patients are completely asymptomatic between attacks; if untreated with prophylactic colchicine, some patients later develop amyloidosis and renal failure. The recent cloning of the FMF gene on the short arm of chromosome 16p, and the subsequent finding that its tissue expression is limited to granulocytes, has helped to explain the dramatic accumulation of neutrophils at the symptomatic serosal sites; the wild-type gene likely acts as an upregulator of an anti-inflammatory molecule or as a downregulator of a pro-inflammatory molecule. For nearly half a century, FMF was thought to cluster primarily in non-Ashkenazi Jews, Arabs, Armenians, and Turks, although the screening of the 8 known mutations in an American cohort has identified substantial numbers of people from the Ashkenazi Jewish and Italian populations in the United States who also have this disease. Nevertheless, the symptoms often go unrecognized and patients remain undiagnosed for years, not receiving the highly efficacious colchicine therapy; their histories often include multiple laparotomies, laparoscopies, and psychiatric evaluations. The combinations of clinical manifestations among FMF patients are quite heterogeneous, but our American cohort did not establish any connections between individual mutations and specific clinical pictures--as is seen in other diseases like cystic fibrosis, in which distinct genotypes target certain organ systems. Specifically, the data from our American series are insufficient to evaluate the hypothesis that the M694V/M694V genotype confers a more severe phenotype, or increases the risk of amyloidosis; but both our data and the recent literature (160) indicate that amyloidosis can occur in FMF patients with only 1 copy, or no copies, of the M694V mutation. It appears that specific MEFV mutations are probably not the sole determinants of phenotype, and that unknown environmental factors or modifying genes act as accomplices in this disease. Although we hope the discovery of the FMF gene will allow the diagnosis of FMF to become genetically accurate, the reality is that both clinical and genetic tools must still be used together unless mutations are identified on both of a patient's chromosomes. Physicians should be careful not to rule out the diagnosis in patients of high-risk ethnic backgrounds just because of atypical clinical features, as our data indicate that MEFV mutations are sometimes demonstrable in such patients. At the same time, physicians cannot yet rely solely on a genetic diagnosis because we have not yet identified a sufficient spectrum of mutations, and it is not currently feasible to examine every patient's full DNA sequence for the entire gene; screening an ethnically consistent and clinically positive patient for the 8 known mutations frequently identifies a mutation on only 1 chromosome, and genetic analysis of other classic cases will often reveal none of the 8 mutations. Still, our data suggest that ethnic background is an important predictor of finding 1 of the presently known mutations, and the knowledge of ancestries atypical for FMF can suggest the diagnosis of other hereditary periodic fever syndromes. As the list of FMF-associated MEFV mutations is expanded, and/or new sequencing technologies permit more rapid screening, the value and interpretation of genetic testing for FMF will become more straightforward. Moreover, as the pathophysiology of this disorder becomes less of a hypothesis and more of an understood entity, it is likely that treatment options will broaden beyond the use of daily prophylactic colchicine. (ABSTRACT TRUNCATED)

Study on the hydrolyzate of sugarcane bagasse to ethanol by fermentation

Study of glucose and xylose utilization by Pichia stipitis in a limited oxygen supply condition revealed that the rate of glucose utilization decreased rapidly while that of xylose decreased slowly until the time that glucose and xylose were shown to level out, at which point the rate of xylose utilization increased rapidly. Based on the results, ethanol fermentation technology in continuous connective tower fermenters was advanced, e.g., fermentation by P. stipitis in an airlift loop tower focusing on xylose utilization and then residue glucose utilization by Saccharomyces cerevisiae in an overflow tower. When the fed hydrolyzate of bagasse was concentrated in five folds and the dilution rate was 0.1 h-1, the total utilization ratio of reducing sugar was 97.2%; the concentration of ethanol was 46.4 g/L.h.

[Effects of oxidatively modified lipoproteins on the expression of monocyte chemoattractant protein-1 in endothelial cells]

OBJECTIVE

To clarify whether lipoproteins, particularly oxidatively modified low density lipoprotein (OX-LDL) and very low density lipoprotein (OX-VLDL) play a role in the express of monocyte chemoattractant protein-1 (MCP-1) mRNA and protein in endothelial cells (ECs).

METHODS

After a 24-hour exposure to LDL, OX-LDL, VLDL and OX-VLDL respectively the total RNA in call aorta ECs was extracted by means of guanidinium isothiocyanate method. MCP-1 mRNA expression in ECs was examined by dot blot analysis using a gamma-32P-end-labelled 35 mer oligonucleotide probe of MCP-1. Meanwhile, MCP-1 protein in EC conditioned media (EC-CM) of each group was determined by sandwich ELISA, and MCP-1 protein in ECs was examined immunocytochemically as well.

RESULTS

Cultured calf aorta ECs expressed MCP-1 mRNA and protein, and OX-LDL and OX-VLDL induced further a strong expression of MCP-1 mRNA, and an increased MCP-1 protein level in EC-CM. The expression of MCP-1 mRNA and protein was only slightly increased when exposed to LDL and VLDL, and immunohistological staining with polyclonal MCP-1 antibody give a similar result.

CONCLUSION

OX-LDL and OX-VLDL are able to induce a strong expression of MCP-1 in ECs.

[Study on changes of plasma substance P in essential hypertension with left ventricular hypertrophy patients and the effect of promoting blood circulation and eliminating phlegm]

OBJECTIVE

Exploring the relationship between the plasma substance P(SP) and essential hypertension with left ventricular hypertrophy (EH-LVH) and the effect of promoting blood circulation and eliminating phlegm.

METHODS

Before and after treatment, the changes of SP in patients wiith EH-LVH were measured by radioimmunoassay. Meanwhile, the changes of plasma renin activity (PRA), angiotension II (Ang II), left ventricular mass index (LVMI) and mean arterial pressure (MAP) were measured.

RESULTS

The level of plasma SP in patients with EH-LVH was markedly lower than that of patients without EH-NLVH and healthy subjects (P < 0.001); the levels of PRA and Ang II were higher than those in control group (P < 0.01 or < 0.05). After treatment, the level of SP was significantly increased, while LVMI, MAP, PRA and Ang II were significantly decrease (P < 0.01 or < 0.05). The levels between SP and LVMI, MAP, PRA, Ang II were markedly negative correlated (P < 0.01) while levels between LVMI and PRA, Ang II were markedly positive correlated.

CONCLUSIONS

The SP may be involved in the pathogenesis of EH-LVH; the mechanism of promoting blood circulation and eliminating phlegm reversing LVH might be related to its increasing the plasma SP.

An intercalated and thermally stable FAPY adduct of aflatoxin B1 in a DNA duplex: structural refinement from 1H NMR

The structure of a formamidopyrimidine (FAPY) adduct arising from imidazole ring opening of the initially formed trans-8, 9-dihydro-8-(N7-guanyl)-9-hydroxyaflatoxin B1 adduct under basic conditions and positioned in the 5'-d(CTATFAPYGATTCA)-3'*5'-d(TGAATCATAG)-3' oligodeoxynucleotide was determined. The FAPY adduct may be a major progenitor of aflatoxin B1-induced mutations in DNA. The freshly prepared sample showed biphasic melting, with transitions at 28 and 56 degreesC. NMR initially showed multiple subspectra. Over a period of several days at 4 degreesC, the sample converted to a single species with a Tm of 56 degreesC, 15 degrees C greater than the unmodified duplex. The deoxyribose was in the beta configuration about the anomeric carbon, evidenced by NOEs between FAPYG5 H3', H2', H2", and H1'. FAPY formation resulted in the loss of the guanine H8 proton, and the introduction of the formyl proton, which showed NOEs to FAPYG5 H1' and A6 N6Ha. A total of 31 NOEs from AFB1 to DNA protons were observed, mostly to the 5'-neighboring base, T4 in the modified strand. Sequential NOEs were interrupted between T4 and FAPYG5 in the modified strand, between C16 and A17 in the complementary strand, and between T4 N3H and FAPYG5 N1H. An NOE between FAPYG5 N1H and C16 N4H showed intact hydrogen bonding at FAPYG5*C16. Upfield chemical shifts were observed for T4 H6 and A17 H8. Molecular dynamics calculations converged with pairwise rmsd differences of <0.9 A. The sixth root residual was 8.7 x 10(-2). The AFB1 moiety intercalated from the major groove between FAPYG5 and T4*A17, and stacked with T4 and FAPYG5 and partially stacked with A17. The base step between T4*A17 and FAPYG5*C16 was increased from 3.4 to 7 A. The duplex unwound by about 15 degrees. The FAPY formyl group was positioned to form a hydrogen bond with A6 N6Ha. Strong stacking involving the AFB1 moiety, and this hydrogen bond explains the thermal stabilization of four base pairs by this adduct, and may be a significant factor in its processing.

[Relationship between the mRNA transcriptions of bFGF and KGF in the carcinogenesis of oral mucosa]

The aim of the study was to determine the expressions and effects of KGF and bFGF of FGF superfamily in oral mucosa. The mRNA transcriptional levels of bFGF and KGF in dysplasia (DYS) and squamous cell carcinoma (SCC) of buccal mucosa were observed and evaluated by in situ hybridization method. The results showed that bFGF and KGF mRNA were expressed by the mesenchymal cells in both DYS and SCC groups, but not in any of the epithelial cells. The positive reactions were located in fibroblasts, endothelial cells and some of the chronic inflammatory cells. There is an increasing mRNA transcriptional level in SCC than in DYS. The results indicated that bFGF and KGF may not only enhance the neovascularization and formation of stroma by autocrine and paracrine action, but also involved in the growth of neoplastic cells.

Cloning and expression of the gene for the active PPi-dependent phosphofructokinase of Entamoeba histolytica

Pyrophosphate-dependent phosphofructokinase (PPi-PFK) from Entamoeba histolytica (HM-1) was purified from trophozoites. Oligonucleotide probes based on partial amino acid sequence were used to clone and sequence the gene and the cDNA of the enzyme. The molecular mass of the subunit was greater than, and the derived sequence significantly different from, that of the product of the PPi-PFK gene previously cloned from E. histolytica [Huang, Albach, Chang, Tripathi and Kemp (1995) Biochim. Biophys. Acta 1260, 215-217; Bruchhaus, Jacobs, Denart and Tannich (1996) Biochem. J. 316, 57-63]. The sequence identity between the two proteins was 17%. The sequence bore greater identity with the more phylogenetically advanced plant PPi-PFKs than with bacterial PPi-PFKs. The cloned cDNA was expressed and the protein purified. The kinetic properties were identical with those of the enzyme isolated from the organism. Furthermore, the specific activity was more than three orders of magnitude higher than that described for the product of the previously cloned E. histolytica PFK gene [Bruchhaus et al. (1996)]. The pH-dependence and apparent substrate affinities of the cloned enzyme were identical with those of the PPi-PFK in trophozoite extracts, indicating that the product of the cloned gene accounts for most if not all of the PFK activity in E. histolytica trophozoites.

Construction of Escherichia coli-Streptomyces shuttle expression vectors for gene expression in Streptomyces

pIJ4123 and pIJ6021 are high-copy-number vectors for gene expression in Streptomyces. They contain a strong, thiostrepton-inducible promoter, PtipA. Two E. coli-Streptomyces shuttle vectors, pHZ1271 and pHZ1272, were constructed by inserting a replicon and bla gene from E. coli into pIJ4123 and pIJ6021, respectively. Both vectors were structurally stable either in E. coli or in Streptomyces lividans. To demonstrate the utility of pHZ1272, the hemoglobin gene of Vitreoscillia (vhb) was cloned into pHZ1272 and expressed in Streptomyces lividans. The expression product (VHb) was detected by Western blotting and carbon monoxide binding activity analysis.

[SERS and electrochemistry studies on the inhibition of thiourea and phenyl-thiourea on iron]

An iron electrode was obtained by depositing a thin layer of iron on active silver electrode with overpotential deposition method. The E - I curve and SERS spectra of thiourea (TU) and phenyl-thiourea (PTU) adsorbed on the iron electrode surface were studied by means of electrochemistry and SERS spectroscopy. The results showed that both TU and PTU can be adsorbed on the iron electrode surface and the inhibition of PTU is better than TU in 0.1mol/L KCl solution. The adsorption mode of TU and PTU is similar in the interaction of S atom and iron surface. The cause of better inhibition effect of PTU lies in that the PTU can be more easily adsorbed on iron electrode because of more negative charge in its S atom and benzene ring in PTU is arranged away from the iron surface to form a rather compact adsorption layer due to steric hindrance.

[Analysis and prevention of road traffic fatalities in Sichuan Province]

This is an epidemiological survey of the fatalities from road traffic accidents in Sichuan. All fatal accidents that occurred in Sichuan from January 1994 to December 1994 were analysed. The mortalities per million kilometers of vehicle travel, per 100,000 registered motor vehicles and per 100,000 resident population were 4.35, 42.41 and 3.92 respectively. These figures were compared with international death rates and those reported by other countries. The results showed that Sichuan had higher mortalities per million kilometers of vehicle travel and per 100,000 registered vehicles but lower mortality per 100,000 resident population, compared with some industrialized and rich develeping countries. The majority of the victims were males aged 21 to 40. Road traffic fatalities constituted the leading cause of all accident deaths. The cost of road accidents in Sichuan was estimated to be sixty million Yuan. Further strategies and methods to minimize the rate of such accidents have been suggested.

[A method based on the theory of stochastic recursive identification for lossless compression of medical images]

This paper describes a method based on the theory of stochastic recursive identification for lossless compression of medical images detail. The performances of this method are compared with the existing method of DPCM through ten X-ray chest images. The experimental results clearly indicate that this method is very valid to realize lossless compression of medical images.

[Cloning and expression in Escherichia coli of an alkaline and thermostable exolipase from Pseudomonas pseudoalcaligenes]

A gene coding for an alkaline and thermostable exolipase of Pseudomonas pseudoalcaligenes was cloned into Escherichia coli LE392 by inserting Sau3 AI-generated DNA fragments into the BamHI site of pIJ285. Four colonies with esterase and lipase activities on the tributyrin agar plate were isolated by screening the constructed pseudomonas pseudoalcaligenes genomic library. Only one out of the four positive colonies showed lipase activity on the agar plate contatining olive oil and Rhodamine-B. Subclones of the 45 kb insert carrying lipase gene was obtained in E. coli HB101 using pUC118 as a vector, two of which (HB101 (pHZ1402) and HB101 (pHZ1403)), retained lipase activity, but the level seems to be different. They carried 3.0 kb and 2.9 kb inserts with a 2 kb overlapping sequence. The lipase activity of HB101 (pHZ1403) is about 4 times higher than that of HB101 (pHZ1402), as 5 times as that of original strain P. pseudoalcaligenes.

Characterization of polymer films of pyrrole derivatives for chemical sensing by cyclic voltammetry, X-ray photoelectron spectroscopy and vapour sorption studies

Eight different conducting polymer films formed from pyrrole and N-substituted pyrrole derivatives were characterized by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy. In particular, the XPS of poly[N-butylpyrrole], poly[N-(2-carboxyethyl)pyrrole], poly[N-(6-hydroxyhexyl)pyrrole] and poly[N-(6-tetrahydropyranylhexyl)pyrrole] is reported for the first time. The vapour sorption properties of these films were also examined by forming the films onto the electrodes of thickness-shear mode acoustic wave sensors. The influence of the pendant side chain is apparent in both the electrochemical behaviour, composition, doping level, morphology and the nature and extent of polymer-vapour interactions. The latter can be rationalized by consideration of vapour physical properties and solvatochromic parameters.

A high-resolution genetic map of the familial Mediterranean fever candidate region allows identification of haplotype-sharing among ethnic groups

Familial Mediterranean fever (FMF) is a recessive disorder of inflammation caused by mutations in a gene (designated MEFV) on chromosome 16p13.3. We have recently constructed a 1-Mb cosmid contig that includes the FMF critical region. Here we show genotype data for 12 markers from our physical map, including 5 newly identified microsatellites, in FMF families. Intrafamilial recombinations placed MEFV in the approximately 285 kb between D16S468/D16S3070 and D16S3376. We observed significant linkage disequilibrium in the North African Jewish population, and historical recombinants in the founder haplotype placed MEFV between D16S3082 and D16S3373 (approximately 200 kb). In smaller panels of Iraqi Jewish, Arab, and Armenian families, there were significant allelic associations only for D16S3370 and D16S2617 among the Armenians. A sizable minority of Iraqi Jewish and Armenian carrier chromosomes appeared to be derived from the North African Jewish ancestral haplotype. We observed a unique FMF haplotype common to Iraqi Jews, Arabs, and Armenians and two other haplotypes restricted to either the Iraqi Jewish or the Armenian population. These data support the view that a few major mutations account for a large percentage of the cases of FMF and suggest that some of these mutations arose before the affected Middle Eastern populations diverged from one another.

[Dual-energy separation imaging on an X-ray direct digital imaging system]

A method of dual-energy separation of bone and soft tissue images of chest based on an X-ray direct digital imaging system has been investigated. In this paper, the optimal thickness of the filter for high energy X-ray beam is discussed. An algorithm of correction of scattered radiation is employed before the separation algorithm. The separated images will be shown in the paper. The result shows that it is possible to use an ordinary broad spectral X-ray beam to acquire the dual-energy images for routine X-ray diagnosis.

Simultaneous expression of Borrelia OspA and OspC and IgM response in cerebrospinal fluid in early neurologic Lyme disease

Lyme disease is the major tick-borne disease, caused by Borrelia burgdorferi (Bb). Neurological involvement is common in all stages. In vivo expression of Bb antigens (Ags) and the immune response to them has not been well investigated in the cerebrospinal fluid (CSF). Upregulation of outer surface protein (Osp) C and concomitant downregulation of OspA before tick inoculation of the spirochete has been reported in skin and blood in animals. CSF OspA Ag in early disease suggests otherwise in CSF. Early Ag expression and IgM response in human CSF was investigated here. Paired CSF and serum was collected from 16 early, predominantly erythema migrans Lyme disease patients with neurologic problems, 13 late Lyme disease patients, and 19 other neurologic disease (OND) controls. Samples were examined for IgM reactivity to recombinant Bb-specific Osps using ELISA and immunoblot. Of 12 early Lyme disease patients with neurologic involvement with both CSF and serum IgM against OspC, 7 (58%) had IgM to OspA (n = 5) or OspB (n = 2) that was restricted to the CSF, not serum. Overall, 12 of 16 (75%) of these early Lyme disease patients with neurologic involvement had CSF and serum IgM against OspC. Only 3 of 13 (23%) late Lyme disease patients and none of 19 OND controls had CSF IgM directed against OspC. In conclusion, in CSF, OspC and OspA can be coexpressed, and IgM response to them occurs in early Lyme disease patients with neurologic involvement. This biologic finding may also provide a discriminating marker for CNS infection in Lyme disease.

[Analysis of apoptosis in premalignant and malignant epithelia of buccal mucosa]

To determine the relationship between apoptosis and carcinogenesis of oral mucosa, the distribution patterns of apoptosis in normal (N), inflammation (IF), dysplasia (DYS) and squamous cell carcinoma (SCC) of oral mucosa were evaluated by in situ end-labeling method. Results showed that the apoptosis levels in N and IF were relatively lower and stable, whereas the apoptosis of DYS was the highest one in all observed groups. The apoptosis of DYS and SCC were increased obviously higher than N and IF. The results indicated that apoptosis played an important role in premalignant lesion and malignancy of oral mucosa.

[Employing deconvolution method for correcting scatter in radiography]

It is well known that the scattered-radiation (SR) results in degradation of the images contrast in digital X-ray radiograph. The main reason affecting radiographic image quality is the SR arising from interaction of the photons with object being radiographed and veiling glare from detector system in the II-TV chai imaging system. With the aim of improving the image quality, we employed the Gaussian function to approximate the scattered point spread function (PSF) and determined the fraction of SR, rho and the parameter, sigma experimentally on an individual system; then we built an inverse filter to process the digital chest X-ray images, which were acquired with the same system and transformed in 2-D Fourier tansform operation. The images processed were corrected by using a variable weihting factor and the resulting images are shown in this paper. The method provides a useful way for solving the problem of correction of the SR in digital X-ray images.

Secondary and tertiary structural changes in gamma delta resolvase: comparison of the wild-type enzyme, the I110R mutant, and the C-terminal DNA binding domain in solution

gamma delta Resolvase is a site-specific DNA recombinase (M(r) 20.5 kDa) in Escherichia coli that shares homology with a family of bacterial resolvases and invertases. We have characterized the secondary and tertiary structural behavior of the cloned DNA binding domain (DBD) and a dimerization defective mutant in solution. Low-salt conditions were found to destabilize the tertiary structure of the DBD dramatically, with concomitant changes in the secondary structure that were localized near the hinge regions between the helices. The molten tertiary fold appears to contribute significantly to productive DNA interactions and supports a mechanism of DNA-induced folding of the tertiary structure, a process that enables the DBD to adapt in conformation for each of the three imperfect palindromic sites. At high salt concentrations, the monomeric I110R resolvase shows a minimal perturbation to the three helices of the DBD structure and changes in the linker segment in comparison to the cloned DBD containing the linker. Comparative analysis of the NMR spectra suggest that the I110R mutant contains a folded catalytic core of approximately 60 residues and that the segment from residues 100 to 149 are devoid of regular structure in the I110R resolvase. No increase in the helicity of the linker region of I110R resolvase occurs on binding DNA. These results support a subunit rotation model of strand exchange that involves the partial unfolding of the catalytic domains.

Construction of a 1-Mb restriction-mapped cosmid contig containing the candidate region for the familial Mediterranean fever locus (MEFV) on chromosome 16p 13.3

In this paper we describe the assembly and restriction map of a 1.05-Mb cosmid contig spanning the candidate region for familial Mediterranean fever (FMF), a recessively inherited disorder of inflammation localized to 16p13.3. Using a combination of cosmid walking and screening for P1, PAC, BAC, and YAC clones, we have generated a contig of genomic clones spanning approximately 1050 kb that contains the FMF critical region. The map consists of 179 cosmid, 15 P1, 10 PAC, 3 BAC, and 17 YAC clones, anchored by 27 STS markers. Eight additional STSs have been developed from the approximately 700 kb immediately centromeric to this genomic region. Five of the 35 STSs are microsatellites that have not been previously reported. NotI and EcoRI mapping of the overlapping cosmids, hybridization of restriction fragments from cosmids to one another, and STS analyses have been used to validate the assembly of the contig. Our contig totally subsumes the 250-kb interval recently reported, by founder haplotype analysis, to contain the FMF gene. Thus, our high-resolution clone map provides an ideal resource for transcriptional mapping toward the eventual identification of this disease gene.

[Survey of smoking and human health in Guangdong province]

As part of the national plan in China, 28,979 residents or farmers were surveyed in 1991 in Guangdong province to investigate the relation between smoking and human health. The results showed that the total smoking rate was 40.2%, 58.8% was for male and 1.2% was for female. 56.4% was in city and 38.7% was in rural area. The beginning smoking age was 15-16 years old (5.5%). 8.5% smokers started smoking after 25 years old. Smoking can increase risk of diseases. The incidence of chronic bronchitis, hypertension, gastric ulcer and pulmonary TB in smoking group were significantly higher than that in non-smoking group. No difference was found in the symptoms of panting, cough and phlegm between the two groups. To control smoking is one of the important measures for human health.

[Effects of oxidatively modified low density lipoprotein and very low density lipoprotein on the expression of MCP-1 in macrophages]

OBJECTIVE

To examine whether oxidatively modified low density lipoprotein (OX-VLDL) and very low density lipoprotein (OX-VLDL) induce the expression of MCP-1 mRNA and protein by rabbit peritoneal exudate macrophages, and to clarify what a role of both lipoproteins play in atherogenesis.

METHODS

After exposure of the macrophages to 25 micrograms/ml of LDL, VLDL, OX-LDL and OX-VLDL respectively, and a 24 hour incubation at 37 degrees C, the total RNA was extracted from the cells by guanidinium isothiocyanate method, and the media conditioned by the cultured macrophages were collected. Meanwhile, MCP-1 protein in the conditioned media was determined by using sandwich ELISA. Monocyte migration induced by the media was assayed by micropore filter method using modified Boyden chamber.

RESULTS

After a 24 hour exposure to OX-LDL and OX-VLDL, the MCP-1 mRNA expression in macrophages was markedly increased (3.2-fold and 3.4-fold, respectively), and the level of MCP-1 protein was also increased (2.2-fold and 2.5-fold, separately), and furthermore, the monocyte migration distance was significantly increased. However, the expression of MCP-1 mRNA and protein was only slightly increased when exposed to LDL or VLDL.

CONCLUSIONS

Rabbit peritoneal exudate macrophages can express MCP-1 mRNA and protein, and OX-LDL and OX-VLDL induce stronger MCP-1 mRNA and protein expression in the cells.

[Sequence alterations in p53 gene of hepatocellular carcinoma from high aflatoxin risk area in Guangxi]

OBJECTIVE

Check on the sequence alterations of the p53 gene of hepatocellular carcinoma (HCC) in some areas of Guangxi.

METHODS

40 cases of archival HCC samples were divided into two groups. One includes 26 cases from Fusui--an area notorious for high risk in HCC, AFB1 and HBV; The other includes 14 cases from Yulin where both HCC and HBV were high but AFB1 may be low because rice low in AFB1 was the staple food. Exon 7 were sequenced by DNA direct sequencing. p53 mutational protein and HBsAg were examined by immunostaing.

RESULTS

In the Fusui group, 16/26 (61.5%) cases showed mutation at codon 249 third position G to T transversion to form a hot-spot which is generally considered to be caused by AFB1. In the Yulin group, only one single place-Guigang showed p53 mutation clustered at the hot-spot like Fusui in 3/5 cases (60%), while the other cases demonstrated mutational points in various positions.

CONCLUSION

Besides Qidong and South Africa, a third AFB1 high risk area was demonstrated where HCC is accompanied by p53 gene specific mutation.

[A fast iterative algorithm for adaptive histogram equalization]

In this paper, we propose an iterative algorthm called FAHE., which is based on the relativity between the current local histogram and the one before the sliding window moving. Comparing with the basic AHE, the computing time of FAHE is decreased from 5 hours to 4 minutes on a 486dx/33 compatible computer, when using a 65 x 65 sliding window for a 512 x 512 with 8 bits gray-level range.

[Effects of oxidized low density lipoprotein and very low density lipoprotein on the expression of MCP-1 by monocytes]

Monocyte chemoattractant protein-1 (MCP-1) is a potent chemotatic factor for monocytes. This study aimed at examination of the effects of oxidized low density lipoprotein (OX-LDL) and oxidized very low density lipoprotein (OX-VLDL) on the expression of MCP-1 mRNA and protein by monocytes. The guanidinium isothiocyanate method was used to extract total RNA from monocytes which were exposed to LDL, OX-LDL, VLDL and OX-VLDL for 24 hours respectively and the monocyte derived conditioned media collected. MCP-1 mRNA expression in monocytes was examined by slot blot and Northern blot analysis using a gamma 32P-end-labelled 35 mer oligonucleotide probe of MCP-1. Meanwhile, MCP-1 protein in the conditioned media was examined by use of sandwich ELISA. It was found that monocytes from human peripheral blood can express MCP-1 mRNA and protein after 24 hours incubation at 37 degrees C and the expression of MCP-1 mRNA and protein was markedly increased by a 24 hour exposure to OX-LDL and OX-VLDL, whereas the expression of MCP-1 mRNA and protein was only sightly increased when exposed to LDL and VLDL. It is concluded that monocytes can express MCP-1 that induce additional monocyte migration into the subendothelial space, and that OX-LDL and OX-VLDL enhance this function by inducing stronger MCP-1 expression in monocytes.

A localized linkage map of the citrus tristeza virus resistance gene region

A localized genetic linkage map was developed of the region surrounding the citrus tristeza virus (CTV) resistance gene (designated Ctv) from Poncirus trifoliate L., a sexually compatible Citrus relative. Bulked segregant analysis (BSA) was used to identify potential resistance-associated RAPD fragment markers in four intergeneric backcross families that were segregating for CTV resistance. Eight RAPD fragments were found that were consistently linked to Ctv in the four families. Map distances and locus order were determined with MAPMAKER 3.0, using the results obtained from 59 individuals in the largest family. Also, a consensus map was constructed with JOINMAP 1.3, using pooled results from the four backcross families. Marker orders were identical, except for 1 marker, on these independently developed maps. Family-specific resistance-associated markers were also identified, as were numerous susceptibility-associated markers. The identification of markers tightly linked to Ctv will enable citrus breeders to identify plants likely to be CTV-resistant by indirect, marker-assisted selection, rather than by labor-intensive direct challenge with the pathogen. These markers also provide a basis for future efforts to isolate Ctv for subsequent genetic manipulation.

Very low density lipoprotein and oxidized very low density lipoprotein induce monocyte chemotactic protein 1 in rabbit aortic smooth muscle cells

OBJECTIVE

To understand whether very low density lipoprotein (VLDL) and oxidatively modified very low density lipoprotein (OX-VLDL) can stimulate vascular smooth muscle cells (SMCs) to express high level of monocyte chemotactic protein (MCP-1) mRNA.

METHODS

LDL and VLDL were isolated from normal blood donors by density gradient ultracentrifugation and oxidatively modified by adding CuCl2 and incubation at 37 degrees C for 24 hours. Rabbit aortic SMCs were cultured by a substrate-attached explant method, and their total RNA was extracted by guanidinium isothiocyanate method. The expression of MCP-1 mRNA in SMCs was examined by dot blotting analysis using a probe of gamma-22P-end-labeled 35-mer oligonucleotide.

RESULTS

Dot blotting analysis showed that cultured SMCs can express MCP-1 mRNA and the level of MCP-1 mRNA was increased significantly in SMCs after 24-hour coculture with VLDL (6-fold) and OX-VLDL (20-fold).

CONCLUSIONS

VLDL and OX-VLDL both can induce MCP-1 mRNA expression in cultured rabbit aortic SMCs and the latter is more effective than the former.

Partial purification of smooth muscle cell derived growth factor

The serum free medium conditioned by cultured rabbit aortic smooth muscle cells was partially purified using ultrafiltration and heparin affinity chromatography. Incorporation of [3H]-thymidine (3H-TdR) into cell DNA was used to measure the mitogenic activity of the fractions from chromatography for NIH 3T3 fibroblasts. The molecular weight and the iso-electric point of these fractions were determined by NaDodSO4-polyacrylamide gel electrophoresis (SDS-PAGE) and iso-electric focusing, respectively. The results showed that the protein eluted in 1.0-1.6 mol/L NaCl from the heparin-Sepharose was mitogenic for 3T3 cells, and this protein had a molecular weight of 22.8-26.7 ku and an iso-electric point of about 4.6. The fact that the above-mentioned biochemical properties differed from that of PDGF, IGF and FGF suggests that this mitogenic protein may be a separate growth factor.

Detection of Borrelia burgdorferi-specific antigen in antibody-negative cerebrospinal fluid in neurologic Lyme disease

OBJECTIVE

To determine the potential of detection in CSF of specific Borrelia burgdorferi antigen, OspA, as a marker of infection in neurologic Lyme disease and compare this with the detection of antibody.

DESIGN

CSF from 83 neurologic patients in an area highly endemic for Lyme disease was examined prospectively for (1) OspA by antigen capture ELISA and Western blot employing monoclonal antibodies, and for (2) B burgdorferi antibodies by ELISA.

RESULTS

Of the 35 of 83 (42%) patients who were positive for OspA antigen in their CSF, 15 (43%) were antigen positive despite being antibody-negative in CSF. Seven of these 15 (47%) had otherwise normal routine CSF analyses. Six of these 15 (40%) patients met strict CDC surveillance criteria for Lyme disease; four (27%) patients had seroconversion coincident with new neurologic problems; and three (20%) with characteristic syndromes for Lyme disease were seronegative, but had complexed antibody to B burgdorferi. The final two patients (13%) were seropositive and had unexplained neurologic problems not characteristic of Lyme disease.

CONCLUSIONS

B burgdorferi antigen can be detected in CSF that is otherwise normal by conventional methodology, and can be present without positive CSF antibody. Since CSF antigen implies intrathecal seeding of the infection, the diagnosis of neurologic infection by B burgdorferi should not be excluded solely on the basis of normal routine CSF or negative CSF antibody analyses.

Investigation of high-resolution angle sensing with laser mode-split technology

We present a new method of angular measurement, which is to rotate a 15-mm-diameter, 3-mm-thick crystal quartz plate in a He-Ne laser cavity to produce a laser mode split. The magnitude of the mode split (in hertz) represents the angle of rotation. The experimental devices used are described. The stability of the beat frequency is 0.78 kHz (1σ). A sensitivity of 2.62 3 × 10(4) Hz/", where" is angular seconds, has been reached and the repeatability is 0.3". The principal error factors are discussed.

Mapping of two phenol sulphotransferase genes, STP and STM, to 16p: candidate genes for Batten disease

The cytosolic phenol sulphotransferase gene (STP) was mapped to a region of chromosome 16, within the interval defined by human-rodent somatic cell hybrid breakpoints CY160(D) and CY12, which contains FRA16E. YAC and cosmid clones from this 16p interval were screened for the presence of STP. Two non-overlapping cosmid contigs were identified which contain STP-like sequences. Sequencing of these STP-like sequences confirmed that STP is contained within contig 343.1 and maps proximal to FRA16E, and that a related sulphotransferase STM, encoding the catecholamine-sulphating enzyme, is contained within contig 55.4 and maps to the adjacent hybrid interval CY12-CY180A. Thus two phenol sulphotransferase genes (STP and STM) have been finely localised to chromosome 16p12.1-p11.2, to the same region as CLN3, the gene for Batten disease. Both genes are therefore candidate genes for Batten disease.

Repeated polyketide synthase modules involved in the biosynthesis of a heptaene macrolide by Streptomyces sp. FR-008

Genes for biosynthesis of a Streptomyces sp. FR-008 heptaene macrolide antibiotic with antifungal and mosquito larvicidal activity were cloned in Escherichia coli using heterologous DNA probes. The cloned genes were implicated in heptaene biosynthesis by gene replacement. The FR-008 antibiotic contains a 38-membered, polyketide-derived macrolide ring. Southern hybridization using probes encoding domains of the type I modular erythromycin polyketide synthase (PKS) showed that the Streptomyces sp. FR-008 PKS gene cluster contains repeated sequences spanning c. 105kb of contiguous DNA; assuming c. 5 kb for each PKS module, this is in striking agreement with the expectation for the 21-step condensation process required for synthesis of the FR-008 carbon chain. The methods developed for transformation and gene replacement in Streptomyces sp. FR-008 make it possible to genetically manipulate polyene macrolide production, and may later lead to the biosynthesis of novel polyene macrolides.

Molecular cloning of the human nucleotide-excision-repair gene ERCC4

ERCC4 was previously identified in somatic cell hybrids as a human gene that corrects the nucleotide-excision-repair deficiency in mutant hamster cells. The cloning strategy for ERCC4 involved transfection of the repair-deficient hamster cell line UV41 with a human sCos-1 cosmid library derived from chromosome 16. Enhanced UV resistance was seen with one cosmid-library transformant and two secondary transformants of UV41. Cosmid clones carrying a functional ERCC4 gene were isolated from a library of a secondary transformant by selecting in Escherichia coli for expression of a linked neomycin-resistance gene that was present in the sCos-1 vector. The cosmids mapped to 16p13.13-p13.2, the location assigned to ERCC4 by using somatic cell hybrids. Upon transfection into UV41, six cosmid clones gave partial correction ranging from 30% to 64%, although all appeared to contain the complete gene. The capacity for in vitro excision of thymine dimers from a plasmid by transformant cell extracts correlated qualitatively with enhanced UV resistance.

Streptomyces lividans 66 contains a gene for phage resistance which is similar to the phage lambda ea59 endonuclease gene

The DNA of wild-type Streptomyces lividans 66 is degraded during electrophoresis in buffers containing traces of ferrous iron. S. lividans ZX1, a mutant selected for resistance to DNA degradation, simultaneously became sensitive to phi HAU3, a wide-host-range temperate bacteriophage. A DNA fragment conferring phi HAU3 resistance was cloned; it contains a phage resistance gene whose deduced amino acid sequence is similar to the phage lambda Ea59 endonuclease. The S. lividans phi HAU3 resistance does not seem to be a classical restriction-modification system, because no host-modified phages able to propagate on the wild-type strain could be isolated. The cloned fragment did not make the host DNA prone to degradation during electrophoresis, indicating that the two phenotypes are controlled by different genes which were deleted together from the chromosome of ZX1.

Characterization of phi HAU3, a broad-host-range temperate streptomyces phage, and development of phasmids

phi HAU3 is a temperate Streptomyces phage with cohesive ends and a broad host range that includes Streptomyces hygroscopicus 10-22, a producer of antifungal compounds, but it fails to grow on Streptomyces lividans 66. Two phasmid derivatives were constructed that function as lambda cosmid vectors in Escherichia coli and as phages in Streptomyces spp.