UV photoelectron and theoretical characterization of 2'-deoxyguanosine-5'-phosphate valence electronic properties: changes in structure associated with the B to Z-DNA conformational transition

He(I) UV photoelectron spectroscopy and ab initio SCF molecular orbital calculations with the 4-31G basis set have been employed to characterize the valence electronic structures of 2'-deoxyguanosine-5'-phosphate (5'-dGMP-). In 5'-dGMP-, the electron distributions of the upper occupied orbitals are localized and similar to those appearing in 1,9-dimethylguanine (1), 3-hydroxytetrahydrofuran (2) and CH3HPO4- (3). Theoretical ionization potentials (IP's) of 5'-dGMP- (4) have been obtained by applying Koopmans' Theorem to the 4-31G SCF results. The IP's of seven orbitals in the base and sugar groups in 4, predicted from the 4-31G SCF calculations, have been individually corrected by comparison to results from 4-31G SCF calculations on neutral 5'-dGMP, and to Hel photoelectron spectra of the model compounds, 1 and 2. The IP's of six of the highest occupied orbitals of the phosphate group in 4 and in the model anion 3, predicted from 4-31G SCF calculations, have been corrected by comparing 4-31G SCF results for PO2- to theoretical IP's obtained from second-order Møller-Plesset perturbation calculations on PO2-. For 4 in the conformation occurring in B-DNA, the first IP's associated with the phosphate, base, and sugar groups occur at 5.1, 5.6 and 6.6 eV, respectively. A comparison of the valence electronic structures of 4 in geometries associated with the B and Z-DNA conformations indicates that in B-DNA the base and sugar orbitals have lower IP's than in Z-DNA, while the phosphate orbitals have higher IP's.

Construction of a dominant selectable marker using a novel dihydrofolate reductase

Simian virus 40 promoter-enhancer-based mammalian expression plasmids using dihydrofolate reductase (DHFR)-encoding cDNA sequences originally isolated from two methotrexate (MTX)-resistant, DHFR-overproducing Chinese hamster lung cell lines were constructed. One, designated pSVA75, contains a DHFR cDNA that encodes leucine (Leu22) and corresponds to the wild type (wt), MTX-sensitive form of the enzyme [Melera et al., J. Biol. Chem. 263 (1988) 1978-1990]. The other plasmid, pSVA3, contains a cDNA that encodes a novel mutant form of the enzyme in which Leu22 has been changed to Phe [Melera et al., Mol. Cell Biol. 4 (1984) 38-48]. The resulting DHFR displays a 20-fold-enhanced resistance to inhibition by MTX, but maintains the catalytic activity of the wt enzyme [Albrecht et al., Cancer Res. 32 (1972) 1539-1546]. Transfection of DHFR- Chinese hamster ovary cells with either plasmid demonstrated that both were able to reconstitute the DHFR+ phenotype with equal efficiency (i.e., greater than 2.5 x 10(-3), indicating that both the wt and mutant enzymes were catalytically active in transfected cells. In addition, the mutant form of the enzyme was found to act as a dominant selectable marker when transfected into diploid DHFR+ cells, and to allow selection of resistant clones at low MTX concentrations (125 nM MTX) with a frequency of greater than 8 x 10(-4). Moreover, transfected clones were found to amplify their exogenous DHFR sequences to reasonably high levels (42-fold) at relatively low (888 nM) MTX concentrations, suggesting that substantial amplification of DHFR DNA and cotransfected sequences as well, can be achieved with this vector.

Nucleotide sequence of the genome of the filamentous bacteriophage I2-2: module evolution of the filamentous phage genome

The nucleotide sequence of the circular single-stranded genome of the filamentous Escherichia coli phage I2-2 has been determined and compared with those of the filamentous E. coli phages Ff(M13, fl, or fd) and IKe. The I2-2 DNA sequence comprises 6744 nucleotides; 139 nucleotides less than that of the N- and I2-plasmid-specific phage IKe, and 337 (336) nucleotides more than that of the F-plasmid-specific phage Ff. Nucleotide sequence comparisons have indicated that I2-2, IKe, and Ff have a similar genetic organization, and that the genomes of I2-2 and IKe are evolutionarily more closely related than those of I2-2 and Ff. The studies have further demonstrated that the I2-2 genome is a composite replicon, composed of only two-thirds of the ancestral genome of IKe. Only a contiguous I2-2 DNA sequence of 4615 nucleotides encompassing not only the coat protein and phage assembly genes, but also the signal required for efficient phage morphogenesis, was found to be significantly homologous to sequences in the genomes of IKe and Ff. No homology was observed between the consecutive DNA sequence that contains the origins for viral and complementary strand replication and the replication genes. Although other explanations cannot be ruled out, our data strongly suggest that the ancestor filamentous phage genome of phages I2-2 and IKe has exchanged its replication module during evolution with that of another replicon, e.g., a plasmid that also replicates via the so-called rolling circle mechanism.

[Construction of phage vector for Bacillus subtilis]

Recombinant phages phi 105S35 and phi 105S36, derived from phage phi 105DI:1t, remain the ability to infect and be lysogenized in the host cell. In the their genome there is a 1 kb inset fragment which occurs between the DNA fragments D and E resulted from SmaI degested DNA of phi 105DI:1t. But the orientation of this insert fragment is opposite in two recombinant phages, respectively. The cat gene on this fragment makes the host cell resistant to chloramphenaical. The unique BamHI and XbaI sites which were introduced into the genome of the recombinant phages provide inserting sites of foreign DNA fragment. DNA from these two recombinant phages can transfect protoplast of Bacillus subtilis at high frequency. Therefore, phi 105S35 and phi 105S36 are suitable as phage vectors in the molecular cloning of Bacillus subtilis.

[Immunopathological study of synovium of rheumatoid arthritis]

46 patients with different rheumatic disorders were subjected to arthroscopic examination and the biopsied synovia were studied immunopathologically. Immunoglobulins, complements and fibrinogen deposition were detected by direct immunofluorescence, and rheumatoid factor (RF) deposition was detected by peroxidase-labelled denatured human IgG. Postoperative diagnosis of these cases were as follows: rheumatoid arthritis (RA) 21; seronegative spondylarthropathy 4; reactive arthritis 2; unidentified synovitis 4; osteoarthritis 8; and nonsynovitis conditions 5. It was shown that the positive rates of deposition of IgG, IgM, complement C3, C1q and C4, and RF in RA were 95.2%, 52.4%, 38.1%, 28.6%, 9.5% and 42.9%, respectively. Deposition was negative in all other rheumatic diseases. The positive fibrinogen deposition rate in RA was 42.9%; it was weakly positive in other disorders as well. The results indicate that the pathogenesis of RA is related to humoral immunity, and immunopathological study of the synovium has very important diagnostic significance in RA. On the other hand, deposition of fibrinogen lacks specificity for any rheumatic disease. The deposition of RF IgG, IgM and complement C3, C1q and C4 in the synovium of RA patients does not correlate well with clinical disease activity. The deposition of RF in the synovium also does not show paired correlation with blood IgM RF determination. This difference may be explained by the fact that the synovial RF examined in the present study may include all isotypes of RF and that hidden-RF in the blood may give a negative result. The synovium is the site of production of RF, but the degree of pathological change of the synovium of different joints in a single patient may not be uniform. The results of humoral immunity studies of the RA synovium may be influenced by the site selected for synovial biopsy.

Comparison of the autoSCAN-W/A rapid bacterial identification system and the Vitek AutoMicrobic system for identification of gram-negative bacilli

The autoSCAN-W/A (W/A; Baxter MicroScan, West Sacramento, Calif.) with the new fluorometric Rapid Neg Combo 1 (RNC) panel is a fully automated fluorometric system for identification of both enteric and nonenteric gram-negative bacilli within 2 h. We compared the W/A with the Vitek AutoMicrobic System (Vitek AMS; Vitek Systems, Inc., Hazelwood, Mo.) for identification of 383 clinical isolates of gram-negative bacilli. The API 20E (Analytab Products, Plainview, N.Y.) and conventional biochemical testing were used as the reference systems. The W/A correctly identified 336 isolates (87.7%) to the species level and classified an additional 29 isolates (7.6%) as correct with low probability (overall identification = 95.3%); the Vitek AMS correctly identified 355 isolates (92.7%) to the species level and classified an additional 8 isolates (2.1%) as correct with low probability (overall identification = 94.8%). A common set of 134 isolates of gram-negative bacilli was tested in both participating laboratories as a means of assessing interlaboratory agreement with both the W/A and the Vitek AMS. The overall agreements between the two laboratories were 86% with the W/A and 92% with the Vitek AMS. The W/A performed comparably to the Vitek AMS for identification of most gram-negative bacilli, actually exceeding the Vitek AMS for identification of nonenteric bacilli. Rapid time to identification and a high level of automation make the W/A an attractive system for clinical microbiology laboratories.

[Pigmentary glaucoma and capsular glaucoma--a clinical and histopathological report]

In this paper, 7 cases (13 eyes) of pigmentary glaucoma and 9 cases (12 eyes) of capsular glaucoma were reported. Pigmentary dispersion in pigmentary glaucoma, pseudo-exfoliation material deposition in capsular glaucoma were the classical characteristics in the anterior segment of the eye, but pigmentary scatter was another clinical feature of capsular glaucoma. The histopathological studies of the trabeculectomy specimens by the light and transmission electron microscopy demonstrated that pigment granules or/and pseudo-exfoliation materials played an important role in obstructing the outflow tract of aqueous humor. In addition, we also discuss the diagnosis and differential diagnosis of both types of glaucoma.

[Clinical significance of determination of urinary albumin, beta 2 microglobulin and Tamm-Horsfall protein in diabetics]

Twenty-four hour urinary albumin (Alb) beta 2 microglobulin (beta 2m) and Tamm-Horsfall protein (THP) were measured by radioimmunoassay in 69 diabetics and 23 normal controls. The excretion of urinary Alb, beta 2m and THP in the patients with diabetic nephropathy was found to be different from that of normal controls. The abnormality of excretion of Alb, beta 2m and THP is particularly evident in the patients with clinical diabetic nephropathy. These results indicate that the renal lesions of diabetes mellitus exist not only in the glomeruli but also in the proximal and/or distal tubules. There was a significantly positive correlation between THP excretion and creatinine clearance (less than 127 ml/min/1.73m2). The findings suggest that the excretion of urinary THP is a valuable index for evaluating the damages of nephrons. It is believed that determination of urinary Alb, beta 2m and THP in diabetics is beneficial to early detection of the sites and degree of the renal lesions.

A domain of the hepadnavirus capsid protein is specifically required for DNA maturation and virus assembly

Mutations introduced into the capsid gene of duck hepatitis B virus (DHBV) were tested for their effects on viral DNA synthesis and assembly of enveloped viruses. Four classes of mutant phenotypes were observed among a series of deletions of covering the 3' end of the capsid open reading frame. Class I mutant capsids were able to support normal single-stranded and relaxed circular viral DNA synthesis; class II mutant capsids supported normal single-stranded DNA synthesis but not relaxed circular DNA synthesis; class III mutant capsids resembled class II capsids, but viral DNA synthesis was inhibited 5- to 10-fold; and class IV capsids were severely restricted in their ability to support viral DNA synthesis. Class I capsids were assembled into enveloped virions, but class II, III, and IV capsids were not. Viral DNA synthesized inside class II capsids was normal with respect to minus-strand DNA initiation, plus-strand DNA initiation, and circularization of the DNA, but plus strands failed to be elongated to mature 3-kb DNA. The results suggest that a function of the capsid protein specifically required for viral DNA maturation is also required for assembly of nucleocapsids into envelopes. Thus, class II mutants appear to be defective in the appearance of the "packaging signal" for virus assembly (J. Summers and W. Mason, Cell 29:403-415, 1982).

Loss of heterozygosity in mammalian cell mutagenesis: molecular analysis of spontaneous mutations at the aprt locus in CHO cells

Loss of heterozygosity at previously heterozygous loci may occur by one of several possible mechanisms and account for a large fraction of all mutations occurring at such loci. In order to investigate loss of heterozygosity events, we have chosen the aprt locus of Chinese hamster ovary (CHO) cells as our model since it is readily available in either heterozygous or hemizygous form. Cloning and sequencing of the two heterozygous aprt alleles from the CHO derivative D423 identified a single polymorphic site, which does not create a restriction fragment length polymorphism. In order to evaluate the loss of heterozygosity events at this locus, we devised a method that creates an artificial restriction fragment length polymorphism in one of these two alleles as a direct consequence of enzymatic amplification. Restriction enzyme digestion of the amplified sequences can then conveniently identify the genotype of the DNA sample. This same methodology also provides for the selective cloning of only one allele of a heterozygous pair into a plasmid vector for subsequent DNA sequence analysis, and can be easily adapted to other situations requiring the analysis of single base changes at a particular position within known sequences. Using this technique, we have determined that 16/37 (43%) spontaneous APRT- mutants had undergone a loss of heterozygosity event.

Dermal nerve sheath myxoma

A case of dermal nerve sheath myxoma on the left palm of 26-year-old Japanese man is presented. We examined this tumor by light and electron microscopies. On light microscopic examination, this tumor was characterized by a multilobulated myxoid tumor composed of stellate cells in an abundant mucous matrix. This histological feature resembled previously reported cases of dermal nerve sheath myxoma. On electron microscopic examination, the findings of these tumor cells were similar to those of the perineurial cells. These microscopical examinations have provided evidence for an origin from perineurial cells rather than Schwann cells.

Clinical application of microcomputer to visual function examination

Microcomputer technique is put into use in ophthalmological clinical visual function examination. In visual EOG, ENG, visual tracking, contrast sensitivity and VEP examination, objectifying and standardization of experiment and data analysis are achieved by computer technique. In addition, a lot of manpower and time is saved, test results are obtained faster and more accurately. The basic rational of computerization in clinical visual function examination is presented.

Amino acid modification of proteins in regenerating sciatic nerves of rats

Recent experiments have shown that Arg, Lys, and Leu can be incorporated posttranslationally into proteins of regenerating sciatic nerves of rats. The present experiments investigate a mixture of 15 radioactive amino acids to determine if additional amino acids can be conjugated posttranslationally to proteins of regenerating nerves. Proteins of regenerating sciatic nerves of rats were able to incorporate Arg, Lys, Leu, Pro, Val, Ala, Phe, and Ser in relatively large amounts and Asp, Glu, Thr, Gly, Ile, His, and Tyr in relatively low or undetectable amounts, in the most advanced portion of the regenerating nerves. Two-dimensional SDS PAGE showed incorporation of the amino acid mixture into distinct radioactive peaks with molecular weights in the 80-90 kD, 53-66 kD, 22-46 kD, and 17 kD ranges with isoelectric points between 5.0 and 7.9. Most of the amino acids were incorporated into proteins in all of the molecular weight ranges. But Ser was incorporated in highest amounts in the 17 kD range, and Val was most abundant in the 22-46 kD range. In some cases results indicated that single proteins were modified by several amino acids. While we do not yet know which amino acids modify specific nerve proteins or the function of the modifications in nerve regeneration, these studies demonstrate the participation of some but not all amino acids in posttranslational modification reactions and the selective modification of specific groups of nerve proteins by these amino acids.

[Studies on ultraweak luminescence of bacteria]

Ultraweak luminescence of Escherichia coli, Bacillus subtilis and Brevibacterium ammoniagenes was measured with high sensitive single photon counting equipment (Made in China). The results obtained from ultraweak luminescence of as above three bacterial strains were as follows: spectral distribution curves, photon emission kinetic curves or emission intensity and its qualitative relationship between intensity and bacterial counts.

Heterogeneity of [3H]estradiol binding sites in the rat prostate: properties and distribution of type I and type II sites

In order to assess the rat prostate as a target tissue for receptor-mediated estrogen action, we have studied the properties and distributions of estrogen binding sites in the dorsolateral (DLP) and ventral (VP) prostate. Saturation analyses over a wide range of [3H]estradiol ([3H]E2) concentrations (0.5-100 nM) revealed two distinct types of binding sites in the cytosol and nuclear fractions of DLP of intact rats. The high affinity (type I) estrogen binding sites saturated at 2-4 nM of [3H]E2 and had a capacity of 170 fmol/mg DNA in the cytosol and 400 fmol/mg DNA in the nuclei. DLP type I sites had ligand specificity similar to that described for the classical estrogen receptors (ERs) found in female target tissues. The moderate affinity (type II) estrogen binding sites saturated at 15-30 nM of [3H]E2 and had a capacity of 850 fmol/mg DNA in the cytosol and 1600 fmol/mg DNA in the nuclei. DLP type II sites shared some characteristics of the type II ERs described for the rat uterus; they were estrogen specific, heat labile, and sensitive to reducing agents such as dithiothreitol. Saturation analyses on VP cytosols and nuclear fractions revealed only high affinity sites but no moderate affinity sites in the tissue preparations. Our finding that prostatic type II estrogen binding sites are present exclusively in the DLP supports the concept that basic biological differences exist between the two major prostatic lobes of the rat. Furthermore, our findings may help elucidate the observed differences in susceptibility between these two lobes to the hormonal induction of proliferative prostatic lesions.

[Antigen presenting cells and T lymphocytes in the induction phase of contact hypersensitivity]

When a sensitizing substance that induces contact hypersensitivity, fluorescein isothiocyanate (FITC), was painted on abdominal skin of mice, FITC+ cells appeared in the inguinal lymph node after 24 hours. The FITC+ cell in the lymph node was relatively large in size, and it did not appear to be a T lymphocyte. When FITC was painted on either murine tail skin or skin pre-treated by tape stripping, the number of FITC+ cells in the inguinal lymph node was significantly less than that in the positive control. In the mesenteric lymph nodes, which have a different lymph flow from that of the skin regional lymph node, FITC+ cells did not increase in number, and the few FITC+ cells were not significantly different in number among above-mentioned experimental systems. In the inguinal lymph nodes on the 4th day after painting of picryl chloride (PCl) on the abdominal skin of mice, L3T4+ cells, which expressed an interleukin 2 receptor (IL-2R), increased in number. On the other hand, when PCl was painted on either tail skin or skin treated by tape stripping, L3T4+ IL-2R+ cells did not increase in the skin regional lymph nodes. The number of L3T4+ IL-2R+ cells in the mesenteric lymph nodes did not increase in any of the experimental systems mentioned above. These results suggest some relationship between antigen presenting cells and T lymphocytes, as well as one between the skin and the regional lymph nodes, in an induction phase of sensitization in contact hypersensitivity.

Flow cytometric analysis of murine splenic cells after DNFB painting on Langerhans cell deficient skin

One week after a single painting of 50 microliters of 0.5% DNFB in acetone-olive oil on the tail skin of C3H mice, the spleens were removed from the animals. A single cell suspension was prepared from the spleens, and flow cytometric analysis was performed for L3T4 and Lyt2 positive cells, as well as for the IJk expression of the Lyt2+ cells. Results showed that the percentages and absolute numbers of Lyt2+ L3T4- cells, Lyt2- L3T4+ cells, Lyt2+ IJk+ cells, and Lyt2+ IJk- cells in the spleens of the DNFB-treated mice were not significantly different from those in the non-treated mice. However, in the treated mice, the IJk expression of Lyt2+ cells intensified. These results indicate that, following a single painting of DNFB onto Langerhans cell-deficient skin, the numbers of Lyt2+ cells do not change significantly, but do change functionally.

Absence of Ig V region gene somatic hypermutation in advanced Burkitt's lymphoma

Somatic hypermutation of rearranged Ig V region gene plays a major role in generating antibody diversity. Recently, V mutation has been established as a major mechanism of tumor escape from anti-Id immunotherapy. We cloned and sequenced the expressed Ig H and L chain V regions from a case of B acute lymphoblastic leukemia in order to evaluate B cell stages associated with V region mutation, and to determine which tumors would be better suited to Id directed immunotherapy. A consensus VH and V lambda sequence representing tumor at diagnosis was obtained by conventional cDNA cloning in lambda gt10 from a heterohybridoma. Primers which flanked both V regions were used in a modified polymerase chain reaction to generate multiple independent sequences from tumor cells harvested at relapse. In order to exclude mutations due to infidelity of the amplification procedure, single cDNA templates of known sequence were also amplified. The polymerase chain reaction proved to be an effective procedure to obtain multiple clones, but replication in M13 was associated with a low rate of base misincorporation. The results indicate that there is no evidence for biologically significant ongoing mutation in this t(8;14) B cell tumor when comparing sequences at diagnosis and relapse. Thus, V somatic mutation may be restricted to a discrete B cell stage whose malignant counterpart is follicular lymphoma.

Absence of Ig V region gene somatic hypermutation in advanced Burkitt's lymphoma

Somatic hypermutation of rearranged Ig V region gene plays a major role in generating antibody diversity. Recently, V mutation has been established as a major mechanism of tumor escape from anti-Id immunotherapy. We cloned and sequenced the expressed Ig H and L chain V regions from a case of B acute lymphoblastic leukemia in order to evaluate B cell stages associated with V region mutation, and to determine which tumors would be better suited to Id directed immunotherapy. A consensus VH and V lambda sequence representing tumor at diagnosis was obtained by conventional cDNA cloning in lambda gt10 from a heterohybridoma. Primers which flanked both V regions were used in a modified polymerase chain reaction to generate multiple independent sequences from tumor cells harvested at relapse. In order to exclude mutations due to infidelity of the amplification procedure, single cDNA templates of known sequence were also amplified. The polymerase chain reaction proved to be an effective procedure to obtain multiple clones, but replication in M13 was associated with a low rate of base misincorporation. The results indicate that there is no evidence for biologically significant ongoing mutation in this t(8;14) B cell tumor when comparing sequences at diagnosis and relapse. Thus, V somatic mutation may be restricted to a discrete B cell stage whose malignant counterpart is follicular lymphoma.

Attomole amino acid determination by capillary zone electrophoresis with thermooptical absorbance detection

Attomole quantities of 4-(dimethylamino)azobenzene-4'-sulfonyl chloride derivatized amino acids are separated by using capillary zone electrophoresis in a mixed acetonitrile/aqueous buffer system. Detection is performed with an on-column thermooptical absorbance detection technique based on a 130-mW argon ion pump laser. Detection limits for the concentration of analyte injected onto the column range from 5 x 10(-8) M for methionine to 5 x 10(-7) M for aspartic acid. Only 37 amol of methionine and 450 amol of aspartic acid are contained within the subnanoliter injection volume. It is interesting to note that these limits are a factor of 4 superior to the best fluorescence detection limit reported for chromatographic separation of amino acids. A subnanoliter sample of derivatized human urine was analyzed with this technique; quantities of amino acids contained within the sample are 3 orders of magnitude greater than the detection limit.

Fungicidal activity of cilofungin (LY121019) alone and in combination with anticapsin or other antifungal agents

Cilofungin (LY121019) was shown to have potent fungicidal activity against clinical isolates of Candida albicans and Candida tropicalis but not Candida parapsilosis. Fungicidal activity was evident against both replicating and non-replicating Candida albicans and was progressive over the first 12 h of incubation. The combination of cilofungin (LY121019) with anticapsin but not with amphotericin B, ketoconazole or 5-fluorocytosine resulted in synergistic fungicidal activity. This compound warrants further investigation of its safety and efficacy in the treatment of Candida infections.

Transcription of the folC gene encoding folylpolyglutamate synthetase-dihydrofolate synthetase in Escherichia coli

The folC gene of Escherichia coli is cotranscribed with an upstream gene from two promoters located in the noncoding region 5' to the coding sequence of the upstream gene. Virtually all of the expression of the folC gene product, folylpolyglutamate synthetase-dihydrofolate synthetase, is therefore due to the upstream gene promoters. No promoter activity was found in the coding sequence of the upstream gene or in the 72-base-pair noncoding region between the two genes. It is shown that a third gene, which may overlap the coding sequence of the folC gene by 8 base pairs at the 3' end, nevertheless, has an promoter independent from that of the upstream gene-folC operon. These results contrast with those presented by Nonet et al. (M. L. Nonet, C. C. Marvel, and D. Tolan, J. Biol. Chem., 262:12209-12217, 1987), who concluded that folC was cotranscribed with the gene at its 3' end and the gene upstream to folC was cotranscribed with the gene(s) further upstream. A stable stem-loop structure resembling a rho-independent terminator is present within the noncoding region between the upstream gene and the folC gene. Folypolyglutamate synthetase expression is 6- to 15-fold lower than that of the upstream gene product, suggesting that the stem-loop terminates some of the transcription from the upstream gene promoter. We found by deletion mutagenesis and cloning sequences containing the stem-loop structure into a termination reporter plasmid that this stem-loop does not act as an effective terminator of transcription. We also found that the stem-loop does not protect the upstream gene message from degradation, since expression of the upstream gene product in maxicell experiments is the same whether the stem-loop structure is present or deleted.

Rat liver ATP-sulfurylase: purification, kinetic characterization, and interaction with arsenate, selenate, phosphate, and other inorganic oxyanions

ATP-sulfurylase (ATP:sulfate adenylyltransferase; EC 2.7.7.4), the first enzyme of the two-step sulfate activation sequence, was purified extensively from rat liver cytosol. The enzyme has a native molecular mass of 122 +/- 12 kDa and appears to be composed of identical 62 +/- 6-kDa subunits. At 30 degrees C and pH 8.0 (50 mM Tris-Cl buffer containing 5 mM excess Mg2+), the best preparations have "forward reaction" specific activities of about 20 and 2 units X mg protein-1 with MoO4(2-) and SO4(2-), respectively. The reverse (ATP synthesis) specific activity is about the same as the forward molybdolysis activity. The kinetic constants under the above conditions are as follows: KmA = 0.21 mM, Kia = 0.87 mM, KmB = 0.18 mM, KmQ = 0.65 microM, Kiq = 0.11 microM, and KmP = 5.0 microM where A = MgATP, B = SO4(2-), Q = APS, and P = total PPi at 5 mM Mg2+. PPi is a mixed-type inhibitor with respect to MgATP and SO4(2-). SeO4(2-) is an alternative inorganic substrate with a Vmax about 20% that of SO4(2-). The product, APSe, is unstable. But in the presence of a sufficient excess of APS kinase, APSe is completely converted to PAPSe. The rate constant for nonenzymatic PAPSe hydrolysis was determined from measurements of the final steady-state reaction rate in the presence of limiting initial SeO4(2-) and a large excess of MgATP, ATP sulfurylase, APS kinase, and the other coupling enzymes and their cosubstrates. The results yielded a k of 2.4 +/- 0.5 X 10(-3) sec-1 (t1/2 ca. 5 min). Phosphate is an effective buffer for enzyme purification and storage but inhibits catalytic activity, particularly at low substrate concentrations. In the presence of buffer levels of Pi, the MgATP reciprocal plot of the SO4(2-)-dependent reaction is concave-up. Inorganic monovalent oxyanions are dead end inhibitors competitive with SO4(2-) and apparently uncompetitive with respect to MgATP. The relative potencies are in the order ClO3- greater than ClO4- greater than FSO3- greater than NO3-. Thiosulfate is also competitive with SO4(2-) but noncompetitive with respect to MgATP. Several divalent oxyanions (MoO4(2-), WO4(2-), CrO4(2-), and HAsO4(2-] promote the enzyme-catalyzed cleavage of MgATP to AMP and MgPPi. The ratio Vmaxf/KmA ranged from 0.7 to 200 for various reactive inorganic substrates. The cumulative results suggest the random binding of MgATP and the inorganic substrate but the ordered release of MgPPi before APS.(ABSTRACT TRUNCATED AT 400 WORDS)

[Course and prognosis of multiple sclerosis. Report of 90 cases]

90 cases of multiple scleroses were studied in connexion with the course and prognosis of the disease. The course of this disease may be classified into 4 type: benign, remitting progressive, and chronic progressive types. Relapse took place in 75% of the patients. The frequency of relapse was on the average 0.45 time per year. Severe disability occurred mostly during the first five years. The present study suggested that the factors indicating relatively poor prognosis would be the onset at the age over 40 years, chronic insidious onset, early severe impairment of the pyramidal tract function and multiple involvement of the different systems in the CNS.

Attomole amino acid determination by capillary zone electrophoresis with thermooptical absorbance detection

Attomole quantities of 4-(dimethylamino)azobenzene-4'-sulfonyl chloride derivatized amino acids are separated by using capillary zone electrophoresis in a mixed acetonitrile/aqueous buffer system. Detection is performed with an on-column thermooptical absorbance detection technique based on a 130-mW argon ion pump laser. Detection limits for the concentration of analyte injected onto the column range from 5 x 10(-8) M for methionine to 5 x 10(-7) M for aspartic acid. Only 37 amol of methionine and 450 amol of aspartic acid are contained within the subnanoliter injection volume. It is interesting to note that these limits are a factor of 4 superior to the best fluorescence detection limit reported for chromatographic separation of amino acids. A subnanoliter sample of derivatized human urine was analyzed with this technique; quantities of amino acids contained within the sample are 3 orders of magnitude greater than the detection limit.

Influence of in vitro susceptibility testing conditions on the anti-candidal activity of LY121019

LY121019 is a new antifungal antimicrobic that is structurally similar to the lipopeptide agents echinocandin B and aculeacin A. Because of the importance of in vitro test conditions on the activity of other antifungal agents, we studied the effects of inoculum size, time and temperature of incubation, pH, and medium composition on the in vitro activity of LY121019 against Candida albicans, Candida tropicalis, and Candida parapsilosis. LY121019 was highly active against Candida albicans and Candida tropicalis and inactive against Candida parapsilosis. The in vitro activity of LY121019 is marked by a paradoxical dose-response with isolates of Candida albicans and Candida tropicalis and is influenced by choice of inoculum size, time and temperature of incubation, medium composition, and pH. We recommend the use of an inoculum size of less than 10(5) organisms/ml, a defined medium buffered to a pH of 7.0, and incubation at 30 degrees C for 24 hr for future in vitro studies of LY121019.

UV photoelectron spectroscopy and ab initio characterization of valence orbital structures and conformations of neutral phosphate esters

The HeI UV photoelectron spectrum of trimethyl phosphate (TMP) has been measured and interpreted with the aid of SCF molecular orbital calculations carried out with STO-3G, STO-3G* and 4-31G basis functions. The photoelectron spectrum of TMP is more accurately reproduced by results from 4-31G calculations than by results from STO-3G or STO-3G* calculations. However, all three basis sets yield results which predict the same assignment of the photoelectron spectrum. Results at the 4-31G level indicate that whether calculations are based on crystallographic bond angles and bond lengths or on STO-3G optimized geometries has little effect on the energetic ordering of the upper occupied orbitals. The energetic ordering of orbitals is also found to be only weakly dependent upon the torsional angle phi, describing rotation of ester groups about P-O bonds and upon the torsional angle psi, describing rotation of methyl groups about C-O bonds. For trimethyl phosphate, with C3 symmetry, the vertical ionization potentials of the upper occupied orbitals are 10.81 eV (8e), 11.4 eV (9a), 11.93 eV (7e), 12.6-12.9 eV (8a and 6e), 14.4 eV (7a) and 15.0-16.0 eV (5e and 6a). Calculations at the 4-31G level indicate that many of the highest occupied orbitals in neutral dimethyl phosphate and methyl phosphate have energies and electron distributions similar to orbitals in TMP. For TMP, a search for optimized values of phi and psi has been carried out at the STO-3G*level. In agreement with previous NMR studies and with classical potential calculations, the STO-3G* results indicate that both the gauche (phi = 53.1 degrees) and anticlinal (phi = 141.9 degrees) conformations are thermally accessible. Also in agreement with the classical potential calculations, the STO-3G* results predict that in the all gauche conformation energy is minimized when the methyl groups assume a staggered geometry (psi = 60 degrees to 80 degrees) and that an energy maximum occurs for an eclipsed geometry (phi = 0 degrees to 20 degrees). A study of the dependence of optimized values of O-P-O ester bond angles on the torsional angles, phi, was carried out at the STO-3G, STO-3G* and 4-31G levels. The results demonstrate that for C3 symmetry, the coupling of O-P-O angles to phi is influence by repulsive steric interactions.

High-affinity binding of [3H]estradiol-17 beta by an estrogen receptor in the liver of the turtle

Specific [3H]estradiol-17 beta ([3H]E2) binding activity (EBA) with characteristics of an estrogen receptor (ER) was demonstrated in cytosols and nuclear extracts of the female turtle, Chrysemys picta. Three different receptor assays (dextran-coated charcoal assay, hydroxylapatite batch procedure, and DNA-cellulose chromatography) were evaluated in terms of their applicability in analyzing large numbers of samples. For the measurement of cytosolic EBA, the hydroxylapatite batch procedure was found to be the most reliable assay. On the other hand, the dextran-coated charcoal assay was found to be the most appropriate method for the measurement of nuclear EBA. Turtle hepatic EBA binds [3H]E2 with high affinity (cytosolic, 17.4 +/- 2.8 X 10(9) M-1; nuclear, 17.7 +/- 1.9 X 10(9) M-1), limited capacity (cytosolic, 133.7 +/- 4.6 fmol/g tissue; nuclear, 81.1 +/- 9.0 fmol/g tissue), and strict steroid specificity. The EBA bound natural estrogens (E2, estrone, estriol) as well as the nonsteroidal estrogen, diethylstilbestrol, but exhibited little affinity for androgens, progesterone, or corticosterone. The turtle hepatic EBA resembled mammalian and avian ERs in terms of binding characteristics; however, unlike mammalian and avian ERs it was shown to be heat-labile. Incubation at 30 degrees caused rapid loss of [3H]E2 binding activity in both cytosolic and nuclear fractions. The exchange between [3H]E2 and the endogenously bound estrogen was slow at 4 and 15 degrees, but the exchange process was facilitated in the presence of the chaotropic salt, NaSCN. Establishment of quantitation methods for both cytosolic and nuclear forms of EBA will enable future investigation of the mechanism and regulation of estrogen action in the liver of this turtle species.

Calcium entry into the inositol 1,4,5-trisphosphate-releasable calcium pool is mediated by a GTP-regulatory mechanism

Intracellular Ca2+ release activated by inositol 1,4,5-trisphosphate (InsP3) plays a pivotal role in Ca2+ signaling in cells. A controlling mechanism for InsP3-induced Ca2+ movements is suggested by results showing that the InsP3-releasable Ca2+ pool is directly modified by a specific and sensitive GTP-regulated Ca2+-translocating process. By using saponin-permeabilized N1E-115 neuroblastoma cells or DDT1MF-2 smooth muscle-derived cells, InsP3 releases 30-50% of Ca2+ accumulated through intracellular high-affinity ATP-dependent Ca2+-pumping activity. Oxalate-promoted Ca2+ uptake is reversed by InsP3, indicating oxalate permeability of the InsP3-releasable pool, which is consistent with this compartment being the endoplasmic reticulum. GTP (10 microM) activates release of 50-70% of accumulated Ca2+ from cells. In the presence of 5-10 mM oxalate, GTP induces a biphasic Ca2+ flux response; initially (1-2 min) GTP induces rapid Ca2+ release followed thereafter by a profound increase in Ca2+ uptake. Thus, GTP-activated Ca2+ influx and efflux compete for Ca2+ access to the oxalate-permeable Ca2+ pool. The nonadditive effects of InsP3 and GTP suggest that InsP3 releases Ca2+ from a subcompartment of the GTP-releasable pool. Most significantly, InsP3 is observed to block the GTP-activated uptake phase in the presence of oxalate, indicating that GTP induces Ca2+ entry into the pool from which InsP3 activates release. Hence, the results provide direct evidence that loading of Ca2+ into the InsP3-sensitive Ca2+ pool is controlled by a GTP-regulated Ca2+-translocating mechanism. Such a process could be significant in regulating the extent and duration of the InsP3-induced Ca2+ signal, a crucial step in the inositol phospholipid signaling pathway.

[Two cases of adrenal myelolipoma]

Myelolipoma of the adrenal gland is a benign oligosymptomatic tumor composed of various proportions of fat and bone marrow elements. We report two operated cases found incidentally in a 76-year-old man and 49-year-old man.

Influenza surveillance in Singapore: 1972-86

Prospective laboratory surveillance of influenza viruses has been carried out since 1973 in Singapore. The results indicate that antigenic shift variants caused epidemics at various times of the year over this period, whereas drift variants were associated with a regular increase in incidence during the second and fourth calendar quarters. Outbreaks due to influenza A virus occurred every year and to influenza B virus at intervals of 16-24 months. Between outbreaks, viruses belonging to either of the two types could be detected during most months, and certain variants appeared several months before the outbreaks they subsequently caused. The factors that contribute to the seasonal pattern are at present unknown.

Effect of morpholinyladriamycin analogs and adriamycin on the activities of DNA polymerase alpha and RNA polymerase II of chicken leukemia cells

The new adriamycin (ADR) derivatives, 3'-deamino-3'-(4"-morpholinyl)adriamycin (MRA) and 3'-deamino-3'-(3"-cyano-4"-morpholinyl)-adriamycin (MRA-CN), were studied, in comparison with ADR, for their inhibitory effects on DNA and RNA syntheses in vitro using isolated DNA and RNA polymerases from both Escherichia coli and chicken (myeloblastosis) leukemia cells. Under standard assay conditions, MRA and ADR demonstrated a similar inhibitory effect on the enzymes, whereas MRA-CN showed a slightly greater inhibitory activity than ADR or MRA at low drug concentrations, but with the inhibitory effect plateauing when drug concentration reached 10 microM. Both the A and B forms of the MRA-CN diastereoisomers were effective as inhibitors. Kinetic studies of the inhibition showed that unlike ADR, MRA-CN inhibition of DNA or RNA synthesis could not be reversed by increasing DNA-template concentration in the reaction mixture. Whereas ADR or MRA relaxed completely 1 microgram of pBR322 supercoiled DNA at a drug concentration of 15 microM, MRA-CN, at 60 microM, produced a mixture of intermediate relaxation forms of the DNA. A complete relaxation was achieved at 300 microM MRA-CN. Both DNA relaxation and fluorescence spectroscopic studies indicated that DNA-drug interactions occurred in the following order: ADR (or MRA) greater than MRA-CN greater than N-trifluoroacetyl-ADR-14-O-hemiadipate (a DNA-nonbinding anthracycline).

Site and stage specific action of endogenous nuclease and micrococcal nuclease on histone genes of sea urchin embryos

The early histone genes of sea urchin embryos are expressed exclusively during cleavage stages of embryogenesis. The chromatin containing these genes was examined by nuclease sensitivity. An endogenous nuclease active during cleavage, produces 1300-bp segments containing early histone genes. The cutting sites have been mapped; there are very sensitive sites close to the cap site for H1, H2A, H2B, and H4. Chromatin obtained from embryos of later stages, when the genes are not expressed, do not display this pattern of nuclease sensitivity. Micrococcal nuclease produces nucleosomes that contain histone genes when used with nuclei from later stages, but not with nuclei from cleavage stages.

Hypoxic and nycthemeral responses by the adrenal cortex of partially hepatectomized rats

Adrenocortical nycthemeral (day-night alteration) and hypoxic stress responses of rats were evaluated 48 h following 70% hepatectomy. Morning plasma and adrenal corticosterone concentrations of hepatectomized (H) rats at 0800 hours were significantly higher than those of sham (S) operated animals. Although both groups showed significant nocturnal elevations in these parameters at 2000 hours, the nocturnal rises in plasma corticosterone levels were 75% and 223% in H and S rats, respectively, yet the absolute steroid levels did not differ between the groups. The hypothalamic-pituitary-adrenocortical (HPA) response of H animals to hypoxia was assessed by measuring plasma corticosterone levels at various times before, during and after exposure to 10% O2 at ground level. Curvilinear analysis of the plasma steroid levels revealed a significantly slower corticosterone rise during the hypoxic phase in H than S animals, as well as a much slower return to baseline levels after the hypoxic stimulus was terminated. The latter indicates a decreased hepatic capacity to inactivate steroids in H animals, while the sluggish activation of the HPA system by hypoxia may be due to altered neuroendocrine control resulting from prior exposure of feedback sites to elevated basal plasma corticosterone levels.

Activation of nonspecific killer cells by interleukin 2-containing supernatants

In the absence of specific antigen stimulation, nonspecific killer cells were induced by culturing C57BL/6 lymph node or spleen cells with interleukin 2-containing supernatants. These supernatants were obtained from stimulation of either rat spleen cells with concanavalin A or a variant of the T cell lymphoma, EL4 (H-2b) with phorbol myristic acetate. The ability of the EL4 supernatant to induce nonspecific killer cells was abrogated by absorption with an interleukin 2-dependent T cell line or by concanavalin A-stimulated spleen cell blasts, but not by lipopolysaccharide-stimulated spleen cell blasts or by a non-interleukin 2-producing EL4 line. Partially purified interleukin 2 from EL4 supernatants could also support nonspecific killer cell induction. The induction of cytolytic cells by interleukin 2 is sensitive to gamma-irradiation and has a D omicron of 120 rad. The nonspecific killer cells induced are likely cytotoxic T lymphocytes; the majority of the precursor and effector cells bear the Thy-1 alloantigen marker. These nonspecific killer cells killed a broad spectrum of target cells, including concanavalin A- and lipopolysaccharide-induced splenic blasts of syngeneic or allogeneic mice, a syngeneic tumor, and a cloned allogeneic cytotoxic T cell line. The frequency of precursors for nonspecific killer cells in C57BL/6 lymph node and spleen cells are 1/7000 and 1/12,000, respectively. Clonal analyses revealed that these nonspecific killers exhibit heterogeneity with respect to their target cell specificities. The induction of nonspecific killers by interleukin 2-containing supernatants is partially dependent on nylon wool-adherent cells; in antigen-stimulated cultures the most specific killer cells were obtained from cultures in which nylon wool-nonadherent lymph node responder cells were stimulated with nylon wool-nonadherent allogeneic splenic stimulator cells that were treated with anti-Thy-1 antibody and complement. The relevance of these findings with respect to the frequencies and fine specificities of cytotoxic T lymphocytes generated in interleukin 2-supplemented cultures is discussed.