Circulating factors and insulin resistance. I. A novel myoinositol 1,2-cyclic phosphate phosphoglycan insulin antagonist from human plasma is elevated in noninsulin-dependent diabetes mellitus

A novel low mol wt inositol phosphoglycan inhibitor (M tau 1200-1500) of insulin action in rat adipocytes has been partially purified from normal human plasma. This inhibitor, termed fraction V after the first purification step and fraction V3 after the second, is different from other reported serum insulin antagonists. It contains myoinositol, galactosamine, and mannose in approximate molar ratios of 1:1:3.3. The myoinositol has a 1,2-cyclic phosphate substituent, which is essential for the inhibitory activity. Its inhibitory activity is significantly elevated (161%, P < 0.05 for fraction V; 278%, P < 0.05 for fraction V3) in plasma of humans with noninsulin-dependent diabetes mellitus as compared with plasma of nondiabetic controls. These findings represent the first report of a naturally occurring mammalian inositol 1,2-cyclic phosphate containing phosphoglycan related to insulin action.

Identification and characterization of a prostaglandin transporter

Carrier-mediated prostaglandin transport has been postulated to occur in many tissues. On the basis of sequence homology, the protein of unknown function encoded by the rat matrin F/G complementary DNA was predicted to be an organic anion transporter. Expression of the matrin F/G complementary DNA in HeLa cells or Xenopus oocytes conferred the property of specific transport of prostaglandins. The tissue distribution of matrin F/G messenger RNA and the sensitivity of matrin F/G-induced prostaglandin transport to inhibitors were similar to those of endogenous prostaglandin transport. The protein encoded by the matrin F/G complementary DNA is thus preferably called PGT because it is likely to function as a prostaglandin transporter.

Biodistribution and metabolism of internally 3H-labeled oligonucleotides. II. 3',5'-blocked oligonucleotides

The pharmacokinetics and metabolism of four radiolabeled phosphodiester oligonucleotides with 3'- and 5'-blocked ends were studied in mice and compared with previously studied, unblocked, all-phosphodiester and all-phosphorothioate oligonucleotides. The radiolabel was a tritiated methyl group enzymatically attached at an internal cytidine. The ends of the blocked phosphodiester oligonucleotides were protected by cyclization or by incorporation of either phosphorothioate or methylphosphonate linkages. Although these modifications protected the blocked oligonucleotides from degradation by exonucleases present in mouse serum, degradation initiated by endonucleases was 50% complete in 0.5-5 hr. After intravenous injection, the blocked oligonucleotides were much less stable than the all-phosphorothioate oligonucleotide and only marginally more stable than the previously studied, unblocked phosphodiester oligonucleotide. Even a "chimeric" blocked oligonucleotide with 16 phosphorothioate linkages and eight contiguous phosphodiester linkages was rapidly degraded. Despite the favorable serum binding, tissue accumulation, and stability observed with phosphorothioate oligonucleotides, these properties did not provide the chimeric oligonucleotide access to a compartment where its phosphodiester linkages were stable. In other respects, the blocked and chimeric phosphodiester oligonucleotides also resembled the unblocked phosphodiester oligonucleotide; radiolabel was cleared rapidly from the blood, there was little evidence of tissue accumulation, high performance liquid chromatographic analysis of tissue extracts showed extremely rapid degradation to mononucleotides, and only mononucleotide metabolites were present in urine. In summary, blocked phosphodiester oligonucleotides are rapidly attacked by endonucleases present in mice. Unless this problem is less serious in primates, such blocked oligonucleotides will be relatively unattractive candidates for drug development.

Direct separation of hydroperoxy- and hydroxy-phosphatidylcholine derivatives: application to the assay of phospholipid hydroperoxide glutathione peroxidase

We have developed a method for assaying the activity of phospholipid hydroperoxide glutathione peroxidase (PHGPx) which is both more sensitive and specific than the spectrophotometric assay. The assay is based on the direct detection of the enzymatic product 1-palmitoyl-2-(13-hydroxy-cis-9, trans-11-octadecadienoyl)-L-3-phosphatidylcholine by HPLC. Under the conditions used, baseline separation is achieved for product and substrate. The utility of the method is demonstrated by the measurement of PHGPx activity in crude extracts from human lenses and from human Hep G2 hepatoma cells. This method is also suitable for measuring the specificity of PHGPx for cofactors apart from glutathione. The assay was used to demonstrate that cysteine alone at pH 7.4 mimics PHGPx activity.

Polarization-maintaining fiber Fabry-Perot tunable filters

We report what are to our knowledge the first high-performance polarization-maintaining single-mode fiber Fabry-Perot tunable filters. These filters simultaneously exhibited a loss of <2.5 dB, a finesse between 150 and 310, and an extinction ratio of >30 dB. A unique fabrication technique is developed that utilizes the tunability and the polarization resonance splitting inside the filter to align the birefringent axes at a pigtail-cavity joint. A general criterion is established for aligning polarization-maintaining fibers with elliptical inputs.

A further study of LDT and IFAT tests in evaluating the control of kala-azar in China

Kala-azar (KA) used to be highly prevalent in Shandong Province in China and, according to the survey made in 1950, the average prevalence rate was 350 per million. Through mass treatment and sandfly control, the prevalence rate was brought down to 3 per 100,000 in 1958 and the disease was basically eliminated. Since 1972, only 18 residual patients have been detected and no newly infected cases have appeared. In the meantime, the vector density had been reduced to such a low level that sandflies could not be found in 85% of the villages. For further evaluation of the control measures, an immunological survey on a relatively large scale was conducted in 78 townships located in 24 counties of 13 prefectures and cities in 1990. A total of 10,239 rural residents of different ages had the Leishmanin dermal test (LDT). None of the people under 30 years of age was positive (0/8020), while in those aged above 30, the average positive rate was 4.4% (98/2219). During the survey, blood samples were also taken from 4232 people for indirect fluorescent antibody test (IFAT); results were all negative. This indicates that the transmission of KA had been completely interrupted since the early 1960s and the province is now a non-endemic area of KA. Further analyses of the data showed that LDT is of great value in epidemiological investigation of KA, for the evaluation of control measurements, the ascertainment of the past and present status of the disease, and detection of subclinical infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Replication intermediates of rice tungro bacilliform virus DNA support a replication mechanism involving reverse transcription

Rice tungro bacilliform virus (RTBV) replication intermediates have been studied in rice plants infected with the virus. Unencapsidated virus-specific molecules were identified which had open circular, linear, supercoiled (SC), strong-stop, single-stranded, linear double-stranded hairpin, and double-stranded with single-stranded extension DNA forms. The structures of these different DNA forms were consistent with the replication model of cauliflower mosaic virus and support other results that reverse transcription is involved in the replication of RTBV. The existence of nonspecific and defective (+)-strand priming is suggested. The relative amount of SC DNAs differs in various tissues of the same plant and in the same tissue at different ages. This indicates host regulation of the virus replication cycle and a feedback regulatory mechanism in controlling the SC DNA level. There are no obvious differences in the composition of the replication intermediates between insect-infected and agroinoculated rice plants.

Fiber Fabry-Perot interferometers with very low polarization sensitivity

The sensitivity to input polarization in long-cavity (1 cm to 5 m) and high-finesse (~ 100) fiber Fabry-Perot interferometers (FFPI's) is reduced from greater than 20 dB to between 0.2 and 0.6 dB in passband amplitude variation by the use of very-low-birefringence fibers. Furthermore the scanning FFPI's could allow very-high-resolution measurement of polarization-mode dispersion in short-length low-birefringence fibers.

Purification and characterization of an oxygen-stable form of dinitrogenase reductase-activating glycohydrolase from Rhodospirillum rubrum

Dinitrogenase reductase-activating glycohydrolase (DRAG) is responsible for removing the ADP-ribose moiety from post-translationally inactivated nitrogenase of Rhodospirillum rubrum. Using DRAG purified from an overexpressing strain (UR276), further properties of this enzyme were studied, including its u.v.-visible and fluorescence spectra and its stability in air. DRAG appears to require no covalently bound inorganic cofactors for its activity or regulation. Previously, purified DRAG was found to be rapidly inactivated in air. The air-catalysed lability originated with the presence of sodium dithionite and Mn2+ throughout the purification of the enzyme. This lability can be mimicked using H2O2, which is known to oxidatively inactivate proteins containing bivalent metals. Implications for the regulation of nitrogenase are discussed with respect to the lack of sensitivity to air of the regulatory enzyme, DRAG.

Fine specificity of B-cell epitopes on Felis domesticus allergen I (Fel d I): effect of reduction and alkylation or deglycosylation on Fel d I structure and antibody binding

The repertoire of B-cell epitopes on the major cat allergen, Fel d I, was analyzed with monoclonal antibodies (MoAbs) in topographic mapping studies and in immunoassays with antigen derived from other cat (Felidae) species. Four essentially nonoverlapping epitopes on Fel d I, designated Fd1A to D, were defined by use of 15 anti Fel d I MoAbs in cross-inhibition radioimmunoassay. Only MoAbs directed against epitope Fd1B bound to putative Fel d I homologues in hair and dander extracts from seven other feline species (Panthera species, [n = 5], Leptailurus serval, and Leopardus pardalus). Quantitative monosaccharide analysis showed that Fel d I was a glycoprotein, containing high levels of fucose, as well as glucosamine, galactose, and mannose. Binding of MoAbs and human IgG or IgE antibody to native, reduced and alkylated or deglycosylated Fel d I was compared by means of immunoprecipitation and immunoassay, and the effects of these treatments on the structure of Fel d I were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis. On reduction and alkylation, Fel d I dissociated into 14 kd and 3.2 kd peptides, and deglycosylation with trifluoromethane sulfonic acid produced a 12 to 14 kd peptide. These procedures resulted in a 100- to 1000-fold loss in murine or human antibody binding activity and caused significant loss of secondary structure, as judged by circular dichroism spectroscopy. Treatment with potassium hydroxide also caused a marked loss in antigenic reactivity. In contrast, enzymatic deglycosylation generated a 9 kd peptide, which showed strong reactivity with murine and human antibodies, comparable to native Fel d I. The results show that MoAbs define a broad repertoire of B-cell epitopes on Fel d I, one of which is expressed by other cat species. These epitopes are conformational and do not appear to involve oligosaccharide residues.

Mapping the 5'-terminus of rice tungro bacilliform viral genomic RNA

The initiation site of the major transcript of rice tungro bacilliform virus (RTBV) has been located by mapping the 5' end of the RNA to nucleotides 7404 and 7405 of the RTBV genome using an RNase protection method. This was confirmed by the 5' RACE PCR procedure which mapped the 5' end of the RNA to nucleotide 7405. These results are consistent with data from our analysis of the strong-stop DNA of RTBV. A eukaryotic RNA polymerase II promoter sequence (TATATAA) was located at nucleotide 7373 of RTBV genome which is 31-32 nucleotides upstream from the proposed initiation site of the RTBV transcript.

[Preparation of digoxigenin labeled virG DNA probe of Shigella and its homology analysis]

Using hapten digoxigenin labeled 1. 4kb virG DNA probe of S. flexneri 2a YSH6000. We examined the DNA homology among 73 strains of Shigella, 32 strains of EIEC, 17 strains of Yersinia, 5 strains of S. typhi and 5 strains of E. coli. At the same time strains of Shigella, EIEC and Yesinia were tested by Sereny assay. We concluded that virG DNA is conserved both in Shigella and EIEC and is related to Sereny test only in Shigella and EIEC but not in Yesinia. The coincidence rate of hybridization and Sereny test was 87.5% and 90.9% for S. sonni and EIEC respectively.

A strong-stop DNA in rice plants infected with rice tungro bacilliform virus

A virus-specific small nucleic acid (strong-stop DNA) was identified in rice plants infected with rice tungro bacilliform virus, but not in the virus particles. This nucleic acid was shown to consist of about 595 deoxyribonucleotides with about 70 ribonucleotides covalently linked at the 5' end. Hybridization with sequence-specific oligonucleotides showed that the ribonucleotides were from the plant cytoplasmic tRNA(iMet) sequence. PCR analysis detected hairpin structures at the 3' end of the DNA.

Preparation of poly(glycolic acid) bonded fiber structures for cell attachment and transplantation

A novel method was developed to prepare three-dimensional structures with desired shapes used as templates for cell transplantation. The produced biomaterials are highly porous with large surface/volume and provide the necessary space for attachment and proliferation of the transplanted cells. The processing technique calls for the formation of a composite material with nonbonded fibers embedded in a matrix followed by thermal treatment and the selective dissolution of the matrix. To evaluate the technique, poly(glycolic acid) (PGA) fiber meshes were bonded using poly(L-lactic acid) (PLLA) as a matrix. The bonded structures were highly porous with values of porosity up to 0.81 and area/volume ratios as high as 0.05 micron-1.

A surface protease and the invasive character of plague

A 9.5-kilobase plasmid of Yersinia pestis, the causative agent of plague, is required for high virulence when mice are inoculated with the bacterium by subcutaneous injection. Inactivation of the plasmid gene pla, which encodes a surface protease, increased the median lethal dose of the bacteria for mice by a millionfold. Moreover, cloned pla was sufficient to restore segregants lacking the entire pla-bearing plasmid to full virulence. Both pla+ strains injected subcutaneously and pla- mutants injected intravenously reached high titers in liver and spleen of infected mice, whereas pla- mutants injected subcutaneously failed to do so even though they establish a sustained local infection at the injection site. More inflammatory cells accumulated in lesions caused by the pla- mutants than in lesions produced by the pla+ parent. The Pla protease was shown to be a plasminogen activator with unusual kinetic properties. It can also cleave complement C3 at a specific site.

Molecular cloning and nucleotide sequence of cDNA encoding human muscle glycogen debranching enzyme

cDNA comprising the entire length of the human muscle glycogen debranching enzyme was cloned and its nucleotide sequence determined. The debrancher mRNA includes a 4545-base pair coding region and a 2371-base pair 3'-nontranslated region. The calculated molecular mass of the debrancher protein derived from cDNA sequence is 172,614 daltons, consistent with the estimated size of purified protein (Mr 165,000 +/- 500). A partial amino acid sequence (13 internal tryptic peptides with a total of 213 residues) determined on peptides derived from purified porcine muscle debrancher protein confirmed the identity of the cDNA clone. Comparison of the amino acid sequence predicted from the human glycogen debrancher cDNA with the partial protein sequence of the porcine debrancher revealed a high degree (88%) of interspecies sequence identity. RNA blot analysis showed that debrancher mRNA in human muscle, lymphoblastoid cells, and in porcine muscle are all similar in size (approximately 7 kilobases). Two patients with inherited debrancher deficiency had a reduced level of debrancher mRNA, whereas two other patients had no detectable abnormality in RNA blots. The isolation of the debrancher cDNA and determination of its primary structure is an important step toward defining the structure-function relationship of this multifunctional enzyme and in understanding the molecular basis of the type III glycogen storage disease.

Characterization of the discontinuities in rice tungro bacilliform virus DNA

The dsDNA of rice tungro bacilliform virus (RTBV) has two discontinuities, one on each strand, each in a specific position as found in other pararetroviruses. The 5' end of discontinuity 1 was mapped to nucleotide 1 of the published RTBV DNA sequence which suggests that tRNAiMet serves as a primer for negative strand DNA synthesis. This 5' terminus contains up to two ribonucleotides and the 3' terminus overlaps it by five to 25 nucleotides. The discontinuity 2 (D2) did not map to a purine-rich region as has been found in other similar viruses. Both the 5' and 3' termini of D2 were heterogeneous in position giving structures varying from a gap of 10 nucleotides to an overlap of 103 nucleotides.

Influence of grating shapes on beam profiles for right-angle guided-wave diffraction

We present simulation results on the influence of grating shapes on diffracted beam profiles for right-angle diffraction. The first-order two-dimensional coupled-mode equations are solved numerically by using the finite-difference method for As(2)S(3) waveguide surface-relief gratings on titanium-indiffused planar waveguides. The simulation results show that square or rectangular gratings result in a distorted profile for the diffracted beam and that truncated grating shapes significantly improve the output beam quality.

Identification of a new mutation in medium-chain acyl-CoA dehydrogenase (MCAD) deficiency

A mutation involving an A-to-G nucleotide replacement at position 985 of the medium-chain acyl-CoA dehydrogenase (MCAD) cDNA was found in homozygous form in 18 unrelated MCAD-deficient families and in heterozygous form in 4 families. By PCR amplification and sequencing of cDNA from a compound heterozygote, we have detected a new mutation in an MCAD-deficient patient in whom one MCAD allele produces mRNA that is missing 4 bp in the MCAD cDNA, while the other allele carries the A-to-G-985 mutation. The presence of this 4-bp deletion was confirmed in the patient's genomic DNA by dot-blot hybridization with allele-specific oligonucleotide probes and by restriction analysis of PCR products. A rapid screening test for this 4-bp deletion was developed, based on mismatched primer PCR amplification. The deletion created a new restrictive-enzyme site which yielded two DNA fragments. The 4-bp deletion was not found in the three remaining MCAD chromosomes not harboring the A-to-G-985 mutation, nor it was present in 20 chromosomes from 10 unrelated normal Caucasians. The PCR-based method for screening these two mutations can detect over 93% of all MCAD mutations.

An improved Tn7-based system for the single-copy insertion of cloned genes into chromosomes of gram-negative bacteria

A system is described for the single-copy, stable insertion of cloned DNA sequences into the chromosomes of Gram- bacteria. Two narrow-host-range plasmids form the basis of this system: the 'carrier' plasmid contains the mini Tn7-Km transposon, into which foreign DNA can be cloned; the 'helper' plasmid provides the Tn7 transposition functions in trans. Both plasmids are readily transferred into Gram- bacteria by conjugation. The functionality of this system has been demonstrated in Rhodospirillum rubrum.

Self-splicing of the Chlamydomonas chloroplast psbA introns

We used alpha-32P-GTP labeling of total RNA preparations to identify self-splicing group I introns in Chlamydomonas. Several RNAs become labeled with alpha-32P-GTP, a subset of which is not seen with RNA from a mutant that lacks both copies of the psbA gene. Hybridization of the GTP-labeled RNAs to chloroplast DNA indicates that they originate from the psbA and rrn 23S genes, respectively, the only genes known to contain group I introns in this organism. Introns 1, 2, and 3 of psbA (with flanking exon sequences) were subcloned and transcribed in vitro. The synthetic RNAs were found to self-splice; splicing required Mg2+, GTP, and elevated temperature. In addition, the accuracy of self-splicing was confirmed for introns 1 and 2, and intermediates in the splicing reactions were detected. These results, together with our recent data on the 23S intron, indicate that the ability to self-splice is a general feature of Chlamydomonas group I introns. These findings have significant implications for the mechanism of group I intron splicing and evolution in Chlamydomonas and other chloroplast genomes.

The gene for von Recklinghausen neurofibromatosis (NF1) maps to the pericentromeric region of chromosome 17 in Chinese families

Linkage analysis of six Chinese families with neurofibromatosis type 1 (NF1) confirms the location of the NF1 gene to the region of the proximal long arm of chromosome 17, as in Caucasian populations. The diagnosis of NF1 was made according to internationally accepted criteria. The markers used were D17S71, D17S58, D17S33, and EVI2A. The overall odds in favor of NF1 lying within this linkage group in the families studied are over 150,000:1, with a maximum location score of 5.112 for the interval D17S58-EVI2A.

[Two biotin-labeled probes of gentamicin resistance genes]

A 2.0 kb BamHI-HindIII fragment of pDG0103 from Australia containing gentamicin 2"-o-adenylytransferase [ANT(2")] gene and a 4.9 kb PstI-EcoRI fragment of pBY102 were recovered from low-temperature-melting agarose by the slot method. Both fragments were labeled with biotin-7-dATP by nick translation with a commercial kit. The result of colony and Southern hybridization was that: the 2.0 kb probe from Australia hybridized with that containing ANT(2") from America, while no hybridization occurred between the 2.0 kb probe and the 4.9 kb probe constructed in our lab. Furthermore, the above two fragments were used as probes for detection of 106 strains of gentamicin resistant Enterobacteriaceae. It revealed that there were more than one gentamicin resistance gene in the tested strains.

[Purification and immunological behavior of beta-lactamase from Bacteroides fragilis]

The beta-lactamase crude extract of Bacteroides fragilis 55 was chromatographed with DEAE-sepharose CL-6B and sephadex G-100. The partial purified enzyme proteins was further purified by cutting the band on PAGE in which the beta-lactamase was distinguishable from other proteins by our method of fluorescent staining. Using purified preparations to be mixed with liposome-CPS-K, prepared specific antisera against the purified beta-lactamase. Serological reactions were carried out by IgG-ELISA together with western blotting. The results revealed that Bacteroides fragilis beta-lactamase possessed its species-specificity.

[Dynamic changes of myocardial beta, alpha 1-adrenergic and muscarinic cholinergic receptors in endotoxic rats]

The dynamic changes of myocardial beta, alpha 1-adrenergic and muscarinic cholinergic receptors (beta AR, alpha 1AR, MAchR) were investigated in endotoxic rats by radiolabelled ligand binding assay. It was found that the number of beta AR increased, while its affinity decreased progressively following endotoxin injection. The number of alpha 1AR reduced significantly during the whole course of the experiment but no change was found in its affinity. The affinity of MAchR was not changed and the number of MAchR reduced only at agonal stage. The up regulation of beta AR in early stage might indicate a compensatory mechanism, while the attenuation in affinity of beta AR and/or the number of alpha 1AR might result in the decreased responsiveness of heart to catecholamine stimulation. Since the affinity of beta AR reduced prominently at the agonal stage, the up regulation of beta AR seemed to be discompensated. The down regulation of MAchR at agonal stage of endotoxic rats might share some light of its compensatory action to the discompromised relationship between the adrenergic and cholinergic system sbut it seemed to be with no effect, which might correlate with myocardial failure.

Esters and lactones of phenolic amino carboxylic acids: prodrugs for iron chelation

The new iron chelator N,N'-bis(2-hydroxyphenyl)ethylenediamine-N,N'-diacetic acid (1), its dilactone 2, N,N'-bis(2-hydroxybenzyl)-2-hydroxypropylene-1,3-diamine-N,N'- diacetic acid (3), and its methyl ester lactone 4 and a series of esters of N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (5) were prepared and their iron chelating efficacy and toxicity determined by using the hypertransfused mouse model of iron overload. The biological activities were compared with results obtained with use of the hypertransfused rat. Esterification enhanced the oral iron chelating activity but also increased toxicity. The diisopropyl ester of 5 exhibited the highest therapeutic index. In vitro measurements showed that the rate of ester hydrolysis at pH 7.5 increased by a factor of 10(4) in the presence of 5 X 10(-4) M ferric ion, which may account for the utility of esters and lactones as prodrugs. Seventeen other chelating agents were screened but showed no intraperitoneal or oral activity.