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1.  Portal hypertension and ascites in systemic mastocytosis. 
Postgraduate Medical Journal  1989;65(764):394-396.
We report a case of systemic mastocytosis (SM) presenting as ascites and portal hypertension. The haematological picture at presentation was suggestive of chronic myelomonocytic leukaemia. Initial difficulties in making a diagnosis of SM were encountered as the cutaneous signs were atypical. The correct diagnosis was established only after tissue sections were appropriately stained for mast cells. The liver biopsy showed portal and sinusoidal mast cell infiltration, portal fibrosis and evidence of hepatic venous outflow obstruction. The disease progressed rapidly and recurrent massive ascites was a dominant problem. This case illustrates again the problems of making a diagnosis of SM especially when the clinical picture is atypical. Ascites as a presenting manifestation of SM has been reported previously in only six patients. Published cases of SM with portal hypertension or ascites or both are reviewed.
PMCID: PMC2429346  PMID: 2608581
2.  An experimental animal model of Kashin-Beck disease. 
Annals of the Rheumatic Diseases  1989;48(2):149-152.
Twelve young macaque monkeys were fed with grain and water from areas actively endemic or non-endemic for Kashin-Beck disease. Both dietary grain and water from geographical areas endemic for Kashin-Beck disease induced a sequence of pathological changes in the growth plates and articular cartilage and biochemical changes in the serum and urine of monkeys. These changes are similar to those in human Kashin-Beck disease. It is considered that this may be a simple and valuable model for the further study of this disease and its management and control. The results suggest that the pathogenetic factors of Kashin-Beck disease relate both to grain and to water in the diet in endemic areas. The experiment also shows that certain serum enzyme concentrations correlate with chondronecrosis.
PMCID: PMC1003703  PMID: 2930266
3.  Cloning and Expression of a Schwanniomyces occidentalis α-Amylase Gene in Saccharomyces cerevisiae 
Applied and Environmental Microbiology  1989;55(12):3167-3172.
An α-amylase gene (AMY) was cloned from Schwanniomyces occidentalis CCRC 21164 into Saccharomyces cerevisiae AH22 by inserting Sau3AI-generated DNA fragments into the BamHI site of YEp16. The 5-kilobase insert was shown to direct the synthesis of α-amylase. After subclones containing various lengths of restricted fragments were screened, a 3.4-kilobase fragment of the donor strain DNA was found to be sufficient for α-amylase synthesis. The concentration of α-amylase in culture broth produced by the S. cerevisiae transformants was about 1.5 times higher than that of the gene donor strain. The secreted α-amylase was shown to be indistinguishable from that of Schwanniomyces occidentalis on the basis of molecular weight and enzyme properties.
PMCID: PMC203241  PMID: 16348077
4.  Novel 12-O-tetradecanoylphorbol-13-acetate-responsive elements in the upstream sequence of the MS gene promoter of Epstein-Barr virus. 
Journal of Virology  1989;63(12):5062-5068.
We have demonstrated that gene expression from the promoter of the Epstein-Barr virus (EBV) MS gene with its upstream sequence is inducible by 12-O-tetradecanoylphorbol-13-acetate (TPA). By transfecting mammalian cells with plasmids in which the MS promoter and its upstream sequence are linked to the bacterial chloramphenicol acetyltransferase gene, we have shown that treatment of the cells with TPA stimulates the expression of chloramphenicol acetyltransferase activity in both EBV-negative and -positive cell lines. This TPA response requires the cis-acting sequence between nucleotides 84440 and 85046 of the EBV genome, located either upstream or downstream of the MS promoter. The TPA induction is at the transcriptional level. When this sequence is linked to the promoter of the human herpesvirus 1 thymidine kinase gene, it can also enhance the expression of, and confer TPA responsiveness on, the thymidine kinase promoter. By constructing and transfecting mutants with 5' and 3' deletions, we have identified two TPA-responsive elements, one located between -726 and -690 and the other located between -603 and -546 relative to the transcription start site. These two sequences do not contain any homology to the previously defined elements for TPA response and may play an important role in EBV induction by TPA.
PMCID: PMC251167  PMID: 2555542
5.  Nodulating Competitiveness of a Nonmotile Tn7 Mutant of Bradyrhizobium japonicum in Nonsterile Soil † 
A nonmotile mutant of Bradyrhizobium japonicum serogroup 127 was generated by Tn7 mutagenesis and matched with the wild type against a common competitor in studies of soybean nodulation in nonsterile soil. The Tn7 mutant was very similar to the wild type in growth rate in culture, soybean lectin-binding ability, flagellar morphology, and nodulating capability, but it had a longer lag phase. Competing strains were distributed uniformly in soil in various ratios and at different population densities prior to planting. Mutant and wild type were equally prevalent in the seedling rhizosphere at about the time of nodule initiation, suggesting that motility conferred no advantage in rhizosphere colonization. Nodulation success of the Tn7 mutant was lower than that of the wild type under all test conditions. Differences were greatest at low soil populations of competitors and much less pronounced at initial populations of 107 g−1. The longer lag phase of the Tn7 mutant may have contributed to its decreased competitiveness, especially at the higher inoculation levels. The antibiotic and motility markers were stable, and the rifampin resistance derived from the parent did not affect adversely the competitiveness of the Tn7 mutant. We found motility to be of limited importance to the competitiveness of a strain in normal nonsterile soil, where the significance, if any, of this ability may be in migration at the immediate root surface in soils sparsely populated with rhizobial symbionts.
PMCID: PMC202975  PMID: 16347986
6.  Overproduction of yeast viruslike particles by strains deficient in a mitochondrial nuclease. 
Molecular and Cellular Biology  1989;9(8):3323-3331.
Saccharomyces cerevisiae strains are often host to several types of cytoplasmic double-stranded RNA (dsRNA) genomes, some of which are encapsidated by the L-A dsRNA product, an 86,000-dalton coat protein. Here we present the finding that nuclear recessive mutations in the NUC1 gene, which encodes the major nonspecific nuclease of yeast mitochondria, resulted in at least a 10-fold increase in amounts of the L-A dsRNA and its encoded coat protein. The effect of nuc1 mutations on L-A abundance was completely suppressed in strains that also hosted the killer-toxin-encoding M dsRNA. Both NUC1 and nuc1 strains containing the L-A genome exhibited an increase in coat protein abundance and a concomitant increase in L-A dsRNA when the cells were grown on a nonfermentable carbon source rather than on glucose, an effect independent of the increase in coat protein due to nuc1 mutations or to the absence of M. The increase in L-A expression in nuc1 strains was similar to that observed in strains with mutations in the nuclear gene encoding the most abundant outer mitochondrial membrane protein, porin. nuc1 mutations did not affect the level of porin in the mitochondrial outer membrane. Since the effect of mutations in nuc1 was to alter the copy number of the L-A coat protein genome rather than to change the level of the M toxin genome (as do mak and ski mutations), these mutations define a new class of nuclear genes affecting yeast dsRNA abundance.
PMCID: PMC362377  PMID: 2552292
7.  The efficiency of 3'-end formation contributes to the relative levels of different histone mRNAs. 
Molecular and Cellular Biology  1989;9(8):3499-3508.
Sequences at both the 5' and 3' ends of mouse histone genes contribute to the expression of individual genes. The 3' sequences required for high expression of the mouse H2a-614 gene are the same as the sequences required for 3'-end formation. When these sequences were substituted for the 3' end of the poorly expressed H2a-291 gene, expression of the H2a-291 gene was increased fivefold. A 65-nucleotide fragment containing the H2a-614 3' processing signal increased expression of the H2a-291 gene when it was placed in the proper orientation downstream of the H2a-291 3' end. The only mRNAs that accumulated from this gene ended at the H2a-291 3' end, which suggests that the transcript is sequentially processed. In an in vitro processing system, the different histone 3' ends showed different processing efficiencies, which correlated with their expression in cells. These results suggest that the efficiency of processing is important in determining the steady-state levels of individual mouse histone mRNAs.
PMCID: PMC362397  PMID: 2796992
8.  Dual bidirectional promoters at the mouse dhfr locus: cloning and characterization of two mRNA classes of the divergently transcribed Rep-1 gene. 
Molecular and Cellular Biology  1989;9(7):3058-3072.
The mouse dihydrofolate reductase gene (dhfr) is a housekeeping gene expressed under the control of a promoter region embedded in a CpG island--a region rich in unmethylated CpG dinucleotides. A divergent transcription unit exists immediately upstream of the dhfr gene which is coamplified with dhfr in some but not all methotrexate-resistant cell lines. We show that the promoter region for this gene pair consists of two bidirectional promoters, a major and minor promoter, which are situated within a 660-base-pair region upstream of the dhfr ATG translation initiation codon. The major promoter controls over 90% of dhfr transcription, while the minor promoter directs the transcription of the remaining dhfr mRNAs. The major promoter functions bidirectionally, transcribing a divergent 4.0-kilobase poly(A) mRNA (class A) in the direction opposite that of dhfr transcription. The predicted protein product of this mRNA is 105 kilodaltons. The minor promoter also functions bidirectionally, directing the transcription of at least two divergent RNAs (class B). These RNAs, present in quantities approximately 1/10 to 1/50 that of the class A mRNAs, are 4.4- and 1.6-kilobase poly(A) mRNAs. cDNAs representing both class A and class B mRNAs have been cloned from a mouse fibroblast cell line which has amplified the dhfr locus (3T3R500). DNA sequence analysis of these cDNAs reveals that the class A and class B mRNAs share, for the most part, the same exons. On the basis of S1 nuclease protection analysis of RNA preparations from several mouse tissues, both dhfr and divergent genes showed similar levels of expression but did show some specificity in start site utilization. Computer homology searches have revealed sequence similarity of the divergent transcripts with bacterial genes involved in DNA mismatch repair, and we therefore have named the divergently transcribed gene Rep-1.
PMCID: PMC362775  PMID: 2674679
9.  Diffusion of the Interspecies Electron Carriers H2 and Formate in Methanogenic Ecosystems and Its Implications in the Measurement of Km for H2 or Formate Uptake 
We calculated the potential H2 and formate diffusion between microbes and found that at H2 concentrations commonly found in nature, H2 could not diffuse rapidly enough to dispersed methanogenic cells to account for the rate of methane synthesis but formate could. Our calculations were based on individual organisms dispersed in the medium, as supported by microscopic observations of butyrate-degrading cocultures. We isolated an axenic culture of Syntrophomonas wolfei and cultivated it on butyrate in syntrophic coculture with Methanobacterium formicicum; during growth the H2 concentration was 63 nM (10.6 Pa). S. wolfei contained formate dehydrogenase activity (as does M. formicicum), which would allow interspecies formate transfer in that coculture. Thus, interspecies formate transfer may be the predominant mechanism of syntrophy. Our diffusion calculations also indicated that H2 concentration at the cell surface of H2-consuming organisms was low but increased to approximately the bulk-fluid concentration at a distance of about 10 μm from the surface. Thus, routine estimation of kinetic parameters would greatly overestimate the Km for H2 or formate.
PMCID: PMC202943  PMID: 16347966
10.  The promoter-regulatory region of the major immediate-early gene of human cytomegalovirus responds to T-lymphocyte stimulation and contains functional cyclic AMP-response elements. 
Journal of Virology  1989;63(7):3026-3033.
Prior studies have demonstrated that a small proportion of blood lymphocytes from patients with human cytomegalovirus (HCMV) infection express only the viral immediate-early (IE) genes (L. Einhorn and A. Ost, J. Infect. Dis. 149:207-214, 1984; G. P. A. Rice, R. D. Schrier, and M. B. A. Oldstone, Proc. Natl. Acad. Sci. USA 81:6134-6138, 1984). The present studies demonstrate that the IE genes of HCMV are transcribed in Jurkat cells (T lymphocytes) only after activation of the cells with mitogens. Transcription of the IE genes is from an upstream enhancer promoter-regulatory region containing several different repeated sequence motifs. Chimeric plasmids were constructed with just a single copy or three copies of a synthetic oligonucleotide sequence of either the 16-, 18-, 19-, or 21-base-pair (bp) repeat elements upstream of the minimal wild-type promoter sequence to drive expression of the indicator gene, chloramphenicol acetyltransferase (CAT). The 18- or 19-bp motifs in the enhancer region were found to be important in mediating the effect of the mitogens. However, the CAT activity detected with the 19-bp repeat was always significantly higher than that found with the 18-bp repeat. There was an additive effect by multiple copies of the 18- or 19-bp repeat sequences on gene expression. The 19-bp repeat contains a sequence identical to that described for a cyclic AMP (cAMP) response element, and plasmids containing only this sequence and the minimal promoter sequences upstream of the CAT gene respond to agents which increase intracellular cAMP. Functional cAMP response elements are present in the wild-type promoter-regulatory region and are associated with the 19-bp repeat sequences. It is proposed that activation of lymphocytes results in expression of the IE genes of HCMV, in part via the activation of cellular trans-acting factors which interact with the 18- and 19-bp motifs in the HCMV IE promoter-regulatory region. The 19-bp repeat is the major contributor to the strength of this enhancer-containing promoter-regulatory region.
PMCID: PMC250857  PMID: 2542610
11.  Angiotensin II stimulates early proximal bicarbonate absorption in the rat by decreasing cyclic adenosine monophosphate. 
These studies explored the hypothesis that angiotensin II increases bicarbonate absorption in the proximal convoluted tubule (PCT) by decreasing intracellular cAMP. In vivo microperfusion was performed in rat PCT with measurements of bicarbonate absorption and of tubular fluid cAMP delivery, as a reflection of intracellular cAMP. Intravenous angiotensin II potently increased S1 PCT bicarbonate absorption (348 +/- 11 to 588 +/- 8 peq/min.min, P less than 0.001) and decreased tubular fluid cAMP (18 +/- 2 to 12 +/- 2 fmol/mm.min, P less than 0.05). Parathyroid hormone had the expected opposite effects, which were additive to those of angiotensin II. Over a wide range of hormonal activities, there was an excellent inverse relationship between hormonally modulated bicarbonate absorption and cAMP delivery. Pertussis toxin pretreatment significantly attenuated (by 35-45%) the angiotensin-induced increase in bicarbonate absorption and decrease in cAMP delivery, indicating Gi-protein intermediation. Luminal dibutyryl cAMP abolished the transport response to angiotensin II. In conclusion, these in vivo results suggest angiotensin II stimulates bicarbonate absorption in the S1 PCT by a G1-mediated depression in intracellular cAMP.
PMCID: PMC303956  PMID: 2544631
12.  Multiple control mechanisms for pyrimidine-mediated regulation of pyrBI operon expression in Escherichia coli K-12. 
Journal of Bacteriology  1989;171(6):3337-3342.
Expression of the pyrBI operon of Escherichia coli K-12, which encodes the subunits of the pyrimidine biosynthetic enzyme aspartate transcarbamylase, is negatively regulated over a several-hundredfold range by pyrimidine availability. This regulation occurs, at least in large part, through a UTP-sensitive attenuation control mechanism in which transcriptional termination at the pyrBI attenuator, a rho-independent transcriptional terminator located immediately upstream of the pyrB structural gene, is regulated by the relative rates of transcription and translation within the pyrBI leader region. There is suggestive evidence that an additional, attenuator-independent control mechanism also contributes to this regulation. To measure the level of regulation that occurs through the attenuation and attenuator-independent control mechanisms, we constructed a mutant strain in which a 9-base-pair deletion was introduced into the attenuator of the chromosomal pyrBI operon. This deletion, which removes the run of thymidine residues at the end of the attenuator, completely abolishes rho-independent transcriptional termination activity. When the mutant strain was grown under conditions of pyrimidine excess, the level of operon expression was 51-fold greater than that of an isogenic pyrBI+ strain. Under conditions of pyrimidine limitation, operon expression was increased an additional 6.5-fold in the mutant. These results demonstrate that the attenuation control mechanism is primarily responsible for pyrimidine-mediated regulation but that there is a significant contribution by an attenuator-independent control mechanism.
PMCID: PMC210055  PMID: 2656651
13.  Heterogeneity of the Ro/SSA antigen. Different molecular forms in lymphocytes and red blood cells. 
Journal of Clinical Investigation  1989;83(4):1293-1298.
Ro(SSA) is an intracellular ribonucleoprotein against which autoantibodies are found in a portion of patients with Sjögren's syndrome and systemic lupus erythematosus. A form of Ro(SSA) is described in red blood cells that shares a line of identity with purified Ro(SSA) from bovine spleen and human lymphocytes in counterimmunoelectrophoresis, but has different molecular properties. Ro(SSA) from red blood cells exists in association with only two small RNAs as opposed to four in other cell types, as determined by RNA extraction of protein A-assisted immunoprecipitates. In addition to the common 60-kD Ro(SSA) protein, Western blot analysis revealed an additional 52-kD protein in lymphocytes and a 54-kD protein in red blood cells. The 60-kD form of Ro(SSA) in red cells was found to be antigenically distinct from that in the lymphocyte, because sera were identified that bound each exclusively. Finally, a rabbit antibovine Ro(SSA) serum distinguished red cell from lymphocyte Ro(SSA). These results suggest two distinctive populations of Ro(SSA) proteins and distributions of Ro(SSA) RNAs in the lymphocyte and red blood cell.
PMCID: PMC303820  PMID: 2784800
14.  Sorption and Metabolism of Metolachlor by a Bacterial Community 
A stable bacterial community absorbed and transformed the herbicide metolachlor [2-chloro-N-(2-ethyl- 6-methylphenyl)-N-(2-methoxy-1-methylethyl)-acetamide] from a liquid medium. About 80% of the added ring-[U-14C]metolachlor (50 μg/ml) disappeared from the medium and accumulated inside the cells. The ratio of cellular 14C to 14C in 1 mg of supernatant reached a value of 1.1 × 104 in a 10-day-old culture. 14C remaining in the medium consisted primarily of two dechlorinated products of metolachlor with m/z 233 and 263 as determined by mass spectrometry. The 14C-labeled material absorbed by the cells was strongly bound; only 2% of the 14C was released into deionized water after shaking for 3 h. Approximately 96% of the 14C associated with the biomass was extracted with acetone, and high-performance liquid chromatographic analysis of this fraction showed six peaks containing radioactivity. Since no metolachlor was detected by chromatographic analysis, it was concluded that the radioactivity recovered from the cells represented transformed products of metolachlor. Pure cultures isolated from the bacterial mixed culture were less effective in transforming and accumulating metolachlor. These results suggest that it may be advantageous to seed an aquatic environment with a mixture of microorganisms, rather than individual microbial species, as a method for removal or detoxification of metolachlor.
PMCID: PMC184188  PMID: 16347880
15.  Genetics and sequence analysis of the pcnB locus, an Escherichia coli gene involved in plasmid copy number control. 
Journal of Bacteriology  1989;171(3):1254-1261.
Mutations at the Escherichia coli pcnB locus reduce the copy number of ColE1-like plasmids. We isolated additional mutations in this gene and conducted a preliminary characterization of its product. F-prime elements carrying the pcnB region were constructed and used to show that the mutations were recessive. The wild-type pcnB gene was cloned into a low-copy-number plasmid, and its nucleotide sequence was determined. The sequence analysis indicated that pcnB is probably the first gene in an operon that contains one or more additional genes of unknown function. The pcnB locus should encode a polypeptide of 47,349 daltons (Da). A protein of this size was observed in minicells carrying a pcnB+ plasmid, and transposon insertions and deletions that truncated this protein generally abolished pcnB function. One exceptional transposon insertion at the promoter-distal end of the pcnB gene truncated the 47-kDa protein by about 20% but did not abolish complementation activity, indicating that the C-terminus of the PcnB product is dispensable. The deduced amino acid sequence of PcnB revealed numerous charged residues and, with 10% arginines, an overall basic character, suggesting that PcnB might interact with DNA or RNA in a structural capacity. Disruption of the pcnB gene by insertional mutagenesis caused a reduction in growth rate, indicating that PcnB has an important cellular function.
PMCID: PMC209738  PMID: 2537812
16.  Risk factors in chronic obstructive pulmonary malfunction and "chronic bronchitis" symptoms in Beijing district: a joint study between Japan and China. 
A cross sectional study of risk factors in respiratory diseases was carried out in August 1986, in Beijing, China. Inhabitants greater than or equal to 40 years old were selected at random from a rural area, a residential area and an industrial area, using a two stage sampling method. The analysis presented here is based on the sample population of adults who (1) were prepared to be interviewed, using the British Medical Research Council's questionnaire translated into Chinese (n = 3423) and (2) had lung function measurements at the same time (n = 3373). Obstructive lung disease was defined as forced expiratory volume in 1s (FEV1) less than 68% of forced vital capacity (FVC). Seven variables were considered as potential risk factors or confounding factors: area of residence, sex, age, cigarette smoking, history of respiratory disease, socio-economic status and familial component. A modified binary variable regression method developed by Feldstein was used for the adjustment of rate ratios. The adjusted prevalence of obstructive lung disease was highest in the rural area and lowest in the residential area(s). An increase in age, cigarette smoking, low socio-economic status and positive history of respiratory diseases were associated with significantly higher rates of impaired pulmonary function. The other measured factors did not appear to be related to impaired pulmonary function.
PMCID: PMC1052783  PMID: 2592885
17.  Insulin-like growth factor binding proteins from cultured human fibroblasts. Characterization and hormonal regulation. 
Journal of Clinical Investigation  1989;83(3):852-859.
Specific, high affinity insulin-like growth factor (IGF) binding proteins are secreted by human fibroblasts in culture. By multiple criteria, the species of IGF binding proteins produced by human fibroblasts are distinct from the HepG2/amniotic fluid IGF binding protein, but share many characteristics with the growth hormone-dependent IGF binding protein forms predominant in normal adult human plasma. Treatment of cultured human fibroblasts with growth hormone produced an increase in IGF binding protein activity in the medium, while addition of glucocorticoids markedly diminished IGF binding activity. Insulin, epidermal growth factor, platelet-derived growth factor, and progesterone had no effect on IGF binding activity in fibroblast media. In comparison, HepG2 IGF binding activity was enhanced by progesterone, decreased by insulin, and unaffected by growth hormone or glucocorticoid treatment. Five molecular forms of IGF binding proteins were identified by Western ligand blots in human fibroblast conditioned medium, with Mr = 41,500, 37,000, 32,000, 28,000, and 23,000. In human fibroblast conditioned medium, the Mr = 41,500 and 37,000 IGF binding protein species were abundant, as in normal human plasma, with a major Mr = 23,000 form which was a minor component in plasma.
PMCID: PMC303758  PMID: 2466052
18.  Nucleotide sequence of a cluster of Escherichia coli enterobactin biosynthesis genes: identification of entA and purification of its product 2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase. 
Journal of Bacteriology  1989;171(2):791-798.
The nucleotide sequence of a region of the Escherichia coli chromosome encoding part of a cluster of genes involved in the biosynthesis of the iron chelator enterobactin has been determined. Four closely linked open reading frames, corresponding to the coding regions of entE (carboxy-terminal 144 amino acids), entB (32,554 daltons), entA (26,249 daltons), and an unidentified gene (P15) encoding a 14,970-dalton protein, were found. The lack of intergenic sequences and promoterlike elements suggests that these genes form part of the same transcription unit. We report the purification to homogeneity of the entA product, 2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase. It is an octamer of native molecular weight 210,000; the amino-terminal amino acid sequence confirmed the entA coding region. No isochorismate synthase activity was associated with this polypeptide. This finding leads to the conclusion that the recent suggestion (M. S. Nahlik, T. P. Fleming, and M. A. McIntosh, J. Bacteriol. 169:4163-4170, 1987) that 2,3-dihydro-2,3-dihydroxybenzoate dehydrogenase and isochorismate synthase activities reside on a single 26,000-dalton bifunctional enzyme is incorrect, even though the entA and entC mutations map to the same genetic locus.
PMCID: PMC209666  PMID: 2521622
19.  Transformation of Metalaxyl by the Fungus Syncephalastrum racemosum† 
The fungus Syncephalastrum racemosum (Cohn) Schroeter was found to transform the fungicide metalaxyl [N-(2,6-dimethylphenyl)-N-(methoxyacetyl)-alanine methyl ester] in pure culture. After 21 days of incubation in a basal medium amended with 5 μg of metalaxyl per ml, more than 80% of the compound was transformed by the fungus. The transformation rates decreased as the concentrations of metalaxyl increased from 5 to 100 μg/ml. No transformation was observed when the concentration of metalaxyl was higher than 200 μg/ml. Two isomeric metabolites and a mixture of two other isomeric metabolites were isolated from the organic extract of the growth medium and identified as N-(2-methyl-6-hydroxymethylphenyl)-N- and N-(2-hydroxymethyl-6-methylphenyl)-N-(methoxyacetyl)-alanine methyl ester and N-(3-hydroxy- and N-(5-hydroxy-2,6-dimethyl-phenyl)-N-(methoxyacetyl)-alanine methyl ester according to their mass-spectral and nuclear magnetic resonance-spectral characteristics. Benzylic hydroxylation of the methyl side chains and/or aromatic hydroxylation appeared to be the major reactions involved in the metabolism of metalaxyl.
PMCID: PMC184055  PMID: 16347836
24.  Bifunctional oligonucleotide probes synthesized using a novel CPG support are able to detect single base pair mutations. 
Nucleic Acids Research  1989;17(18):7187-7194.
A novel multifunctional controlled pore glass, MF-CPG (Fig. 1), has been synthesized and used to incorporate 3' terminal primary aliphatic amines into synthetic oligonucleotides. MF-CPG consists of a unique succinic acid linking arm which possesses both a masked primary amine for label attachment and a dimethoxytrityl protected hydroxyl for nucleotide chain elongation. Using MF-CPG, we have devised a simple and convenient technique to attach non-radioactive labels to the 3' terminus of oligonucleotides. Bifunctional probes can then be constructed by 32P labeling the 5' terminus with T4 kinase and gamma 32P-ATP. Using such bifunctional oligonucleotide probes in conjunction with polymerase chain reaction (PCR) amplification, we were able to detect single base substitutions in a target segment of the human H-ras protooncogene employing either functionality. Our technique thus expands the potential applications for oligonucleotides as hybridization probes.
PMCID: PMC334798  PMID: 2677994
25.  Regulation of the human beta-actin promoter by upstream and intron domains. 
Nucleic Acids Research  1989;17(2):601-615.
We have identified three regulatory domains of the complex human beta-actin gene promoter. They span a region of about 3000 bases, from not more than -2011 bases upstream of the mRNA cap site to within the 5' intron (832 bases long). A distal upstream domain contains at least one enhancer-like element. A proximal upstream domain, with a CArG [for CC(A + T rich)6GG] motif found in all known mammalian actin genes, seems to confer serum, but not growth factor, inducibility. The third domain is within the evolutionarily conserved 3' region of the first intron and contains a 13 base-pair sequence, identical to the upstream sequence with the CArG motif. This domain also contains sequences that are both serum and fibroblast growth factor inducible.
PMCID: PMC331606  PMID: 2915924

Results 1-25 (25)