[A generator for producing multicomponent organic solvent vapor in inhalation chambers]

A vapor generator for multicomponent organic solvents was developed and its performance was investigated experimentally. The vapors were generated from the surface of a sintered sphere of glass beads containing the organic solvents. The solvents were automatically supplied from the solvent reservoir to the sphere by suction pressure caused by the evaporation of the solvents and the generated vapors kept at constant high concentration over a long period. The vapor concentration increased with the decreasing flow rate and the increasing gas temperature. The concentration ratio of the generated vapor was found to be equivalent to the mixing ratio of solvents in the reservoir, so this device can generate multicomponent organic solvent vapors at any concentration ratio. The vapor generator is simple to construct and is recognized to be useful for investigation of inhalation toxicities of multicomponent organic solvent vapors.

Structure of the human renin gene

The human renin gene was isolated from a Charon 4A human genomic library and characterized. The gene spans about 11.7 kilobases and consists of 10 exons and 9 introns that map at points that could be variable surface loops of the enzyme. The complete coding regions, the 5'- and 3'-flanking regions, and the exon-intron boundaries were sequenced. The active site aspartyl residues Asp-38 and Asp-226 are encoded by the third and eighth exons, respectively. The extra three amino acids (Asp-165, Ser-166, Glu-167) that are not present in mouse renin are encoded by the separate sixth exon, an exon as small as 9 nucleotides. The positions of the introns are in remarkable agreement with those in the human pepsin gene, supporting the view that the genes coding for aspartyl proteinases have arisen as the result of duplication of a common ancestral gene. As in most eukaryotic genes, the putative T-A-T-A and C-A-A-T sequences, which may play a role in the initiation of gene transcription, are found in the vicinity of -29 and -51 nucleotides of the cap site. Further upstream, at nucleotides -456 to -451, is located the hexanucleotide T-G-T-T-C-T, which has recently been suggested as a binding site for the glucocorticoid receptor. In the 3'-flanking region, there is the conserved hexanucleotide sequence A-A-T-A-A-A, thought to be necessary for polyadenylylation. Blot-hybridization analyses of the isolated gene clone and the total cellular DNA after digestion with restriction enzymes revealed that human renin is encoded by a single gene.

Selective inhibition of type I collagen synthesis in osteoblastic cells by epidermal growth factor

We have investigated the effect of epidermal growth factor (EGF) on collagen metabolism in clonal MC3T3-E1 cells, an osteoblastic cell line derived from newborn mouse calvaria. EGF significantly increased DNA synthesis, but decreased collagen production. We analyzed the amount of total collagen synthesis and degradation products of collagen together with the level of the enzyme responsible for extracellular collagen degradation, to investigate whether the decreased collagen production was due to a decrease in total collagen synthesis or to an increase in collagen degradation. Total collagen synthesis, determined by total hydroxyproline synthesized, was significantly decreased in cells cultured in medium containing EGF, but the amount of collagen degradation products and the level of animal collagenase activity were not increased. Analysis of the collagen type produced by the cells in the absence of EGF showed that 95% of the collagen recovered was type I and 3% was type III. The decreased level of collagen accumulated by cells cultured in the presence of EGF was explained only by the decreased rate of type I collagen synthesis. These results indicate that EGF selectively inhibits type I collagen synthesis in the clonal osteoblastic cell line, MC3T3-E1.

Molecular cloning and the total nucleotide sequence of the human c-Ha-ras-1 gene activated in a melanoma from a Japanese patient

The transforming gene of malignant melanoma tissue obtained from a Japanese patient and maintained in nude mice has been cloned in its biologically active form and identified as the c-Ha-ras-1 gene, a homologue of the viral Ha-ras gene. Nucleotide sequence analysis revealed that the genetic alteration responsible for the transforming activity of the melanoma oncogene was localized to a single point mutation in the second exon. The transversion of adenine to thymine results in the substitution of leucine for glutamine as amino acid residue 61 of the predicted p21 protein. Other nucleotide sequences spanning a 2.9-kilobase segment including the entire exons and introns were found to be exactly the same as those in a proto-oncogene from a normal Caucasian reported previously, except for base alterations explained as polymorphic differences.

Secondary structure and phylogeny of Staphylococcus and Micrococcus 5S rRNAs

Nucleotide sequences of 5S rRNAs from four bacteria, Staphylococcus aureus Smith (diffuse), Staphylococcus epidermidis ATCC 14990, Micrococcus luteus ATCC 9341 and Micrococcus luteus ATCC 4698, were determined. The secondary structural models of S. aureus and S. epidermidis sequences showed characteristics of the gram-positive bacterial 5S rRNA (116-N type [H. Hori and S. Osawa, Proc. Natl. Acad. Sci. U.S.A. 76:381-385, 1979]). Those of M. luteus ATCC 9341 and M. luteus ATCC 4698 together with that of Streptomyces griseus (A. Simoncsits, Nucleic Acids Res. 8:4111-4124, 1980) showed intermediary characteristics between the gram-positive and gram-negative (120-N type [H. Hori and S. Osawa, 1979]) 5S rRNAs. This and previous studies revealed that there exist at least three major groups of eubacteria having distinct 5S rRNA and belonging to different stems in the 5S rRNA phylogenic tree.

Evolution of multicellular animals as deduced from 5S rRNA sequences: a possible early emergence of the Mesozoa

The nucleotide sequences of 5S rRNA from a mesozoan Dicyema misakiense and three metazoan species, i.e., an acorn-worm Saccoglossus kowalevskii, a moss-animal Bugula neritina, and an octopus Octopus vulgaris have been determined. A phylogenic tree of multicellular animals has been constructed from 73 5S rRNA sequences available at present including those from the above four sequences. The tree suggests that the mesozoan is the most ancient multicellular animal identified so far, its emergence time being almost the same as that of flagellated or ciliated protozoans. The branching points of planarians and nematodes are a little later than that of the mesozoan but are clearly earlier than other metazoan groups including sponges and jellyfishes. Many metazoan groups seem to have diverged within a relatively short period.

Stimulation of prostaglandin synthesis in cultured rat synovial cells by a factor derived from polymorphonuclear leukocytes

Stimulation of synovial cell prostaglandin production by a factor obtained from casein-induced peritoneal polymorphonuclear (PMN) cells has been investigated. Both the extract and short time cultured medium of rat peritoneal PMN cells stimulate prostaglandin (PG)E2 production as well as collagenase production in the culture of rat synovial cells. PGE2 production by the cells in the presence of the PMN factor is much faster (5 to 24 hr) than collagenase production (24 hr or later, Biomedical Res. 3, 506-516, 1982). This stimulating factor is confirmed to be derived from PMN cells, based on the purification of the cells from peritoneal exudate cells by the Ficoll-Urographin method. Elution profile of the factor on gel filtration has indicated that both PGE2 and collagenase productions by synovial cells are stimulated by the same effluent fractions corresponding to molecular weights of 15,000 - 20,000 daltons and 30,000 - 40,000 daltons. These results suggest that PMN cells are involved in PG production as well as collagenase production in the inflamed tissue by stimulating connective tissue cells such as synovial cells.

Contact points between transcription machinery and the fibroin gene promoter deduced by functional tests of single-base substitution mutants

An efficient method for oligonucleotide-directed mutagenesis was developed to construct a set of site-specific mutations by using a mixture of oligodeoxyribonucleotides. With this method, as high as 40% of the tested clones turned out to be desired mutants. Seven single-point mutants were isolated in the "TATA" box region of the fibroin gene. In vitro transcription experiments showed that single-base transversions at the TATA box (A----T at position -29, T----A or G at -28, A----T at -27, and A----T at -26) resulted in decreased promoter activities, whereas A----G transitions at positions -24 and -23 had no effect. The initiation site of transcription was normal in three down-promoter mutants at positions -28 and -26, but the A----T transversions at positions -29 and -27 induced an additional transcription start from position +4. Using 10 single-point mutants obtained as above or by nitrous acid-induced mutagenesis, we have prepared a pair of heteroduplex DNAs consisting of a mutant strand and the wild-type one. The molecules heterozygous at positions -30, -21, and -20 showed reduced transcription activities when the noncoding strand bears the mutation, whereas that at position -26 gave a low activity when the coding strand carries the mutation. Both types of heteroduplex at positions -29, -28, -27, and -17 exhibited decreased activities. These results suggest a transcription machinery contact to a major groove of the DNA helix at the TATA box and region of position -20.

Complementary DNA sequences of renin. State-of-the-art review

The primary structure of human renin precursor was deduced from its complementary DNA (cDNA) sequence. The predicted sequence consists of 406 amino acids with a pre- and a prosegment carrying 20 and 46 amino acids, respectively. A high degree of sequence homology, especially in the catalytically important region, was found upon comparison of the mouse and human renins. An overall homology, including presequence between the two renins, is 68.7%. Close similarities were also observed in the primary structure of renins and other aspartyl proteinases with defined three-dimensional structures, suggesting a tertiary structure for renin that is similar to the other enzymes. A bilobal model of the tertiary structure of human renin with two approximately equal domains separated by a cleft was constructed using the homology of amino acid sequence of renins and other aspartyl proteinases. These results indicate that human kidney renin is homologous with mouse submandibular renin in primary and tertiary structures, proteolytic processing, and catalytic apparatus with small differences. The major structural difference distinguishing the two renins was the presence of the two possible glycosylation sites in human kidney renin, which was not observed in mouse submandibular gland renin.

The nucleotide sequences of 5S rRNAs from a fern Dryopteris acuminata and a horsetail Equisetum arvense

The nucleotide sequences from two Pteridophyta species, a fern Dryopteris acuminata and a horsetail Equisetum arvense have been determined. These two sequences are more related to those of the Bryophyta species (88% identity on average) than to those of seed plants (84% identity on average).

Inhibition of processing of plant N-linked oligosaccharides by castanospermine

Castanospermine (1,6,7,8-tetrahydroxyoctahydroindolizine) is a plant alkaloid that inhibits lysosomal alpha- and beta-glucosidase. It also inhibits processing of influenza viral glycoproteins by inhibiting glucosidase I and leads to altered glycoproteins with Glc3Man7GlcNAc2 structures. Castanospermine was tested as an inhibitor of glycoprotein processing in suspension-cultured soybean cells. Soybean cells were pulse-labeled with [2-3H]mannose and chased for varying periods in unlabeled medium. In normal cells, the initial glycopeptides contained oligosaccharides having Glc3Man9GlcNAc2 to Glc1Man9GlcNAc2 structures and these were trimmed during the chase to Man9GlcNac2 to Man7GlcNAc2 structures. In the presence of castanospermine, no trimming of glucose residues occurred although some mannose residues were apparently still removed. Thus, the major oligosaccharide in the glycopeptides of castanospermine-incubated cells after a 90-min chase was a Glc3Man7GlcNAc2 structure. Smaller amounts of Glc3Man6GlcNAc2 and Glc3Man5GlcNAc2 were also identified. Thus, in plant cells, castanospermine also prevents the removal of the outermost glucose residue.

Cloning and sequence analysis of cDNA for human renin precursor

The primary structure of human renin precursor has been deduced from its cDNA sequence. A library of cDNA clones was constructed from human kidney poly(A)+ RNA by applying the vector/primer method of Okayama and Berg. The library was screened for human renin sequences by hybridization with the previously cloned mouse renin cDNA. Of the 240,000 colonies screened, 35 colonies that were positive for hybridization were isolated. Two recombinant plasmids containing long inserts of about 1,300 and 1,600 base pairs were selected for sequence analysis. The amino acid sequence predicted from the cDNA sequence shows that the human renin precursor consists of 406 amino acids with a pre and a pro segment carrying 20 and 46 amino acids, respectively. A high degree of sequence homology was found upon comparison of the mouse and human renins. Close similarities were also observed in the primary structures of renin and aspartyl proteinases that have known three-dimensional structures, suggesting a similar tertiary structure for renin.

Phylogeny of protozoa deduced from 5S rRNA sequences

The nucleotide sequences of 5S rRNAs from three protozoa, Bresslaua vorax, Euplotes woodruffi and Chlamydomonas sp. have been determined and aligned together with the sequences of 12 protozoa species including unicellular green algae already reported by the authors and others. Using this alignment, a phylogenic tree of the 15 species of protozoa has been constructed. The tree suggests that the ancestor for protozoa evolved at an early time of eukaryotic evolution giving two major groups of organisms. One group, which shares a common ancestor with vascular plants, contains a unicellular green flagellate (Chlamydomonas) and unicellular green algae. The other group, which shares a common ancestor with the multicellular animals, includes various flagellated protozoa (including Euglena), ciliated protozoa and slime molds. Most of these protozoa appear to have separated from one another at a fairly early period of eukaryotic evolution.

The nucleotide sequences of 5S rRNAs from two ribbon worms: Emplectonema gracile contains two 5S rRNA species differing considerably in their sequences

The nucleotide sequences of 5S rRNAs from two nemerteans (ribbon worms), Lineus geniculatus and Emplectonema gracile have been determined. Emplectonema has two 5S rRNA species that are composed of 119 and 120 nucleotides, respectively. The sequences of these two 5S rRNAs differ at 22 positions. On the other hand, only a single 5S rRNA species was found in Lineus. The sequence similarity percents are 88% (Lineus/Emplectonema longer 5S rRNA), 82% (Emplectonema longer/Emplectonema shorter) and 80% (Lineus/Emplectonema shorter). The comparisons of these sequences with those of other organisms suggest that the phylum Nemertinea is most related to the Mollusca (91%) and the Rotifera (89%), but not to fresh-water planarias (72%).

Analysis of powder and single crystal electron paramagnetic resonance spectra of deoxy myoglobins containing cobalt (II) proto-and mesoporphyrins IX at various microwave frequencies

Artificial myoglobins (Mbs) substituted for protoheme with Co(II) proto-and mesoporphyrins IX (proto-and meso-CoMbs, respectively) were prepared. The principal values and eigenvectors of g tensors and the hyperfine coupling tensors of the paramagnetic Co(II) centers of their deoxy forms have been determined by single crystal EPR spectroscopy at 77 K in order to elucidate orientation and electronic structure of the prosthetic group in myoglobin. The orientation of the porphyrin plane of deoxy meso-CoMb were found to be identical to that of deoxy proto-CoMb. However, the in-plane hyperfine coupling constants of deoxy meso-CoMb were more anisotropic and larger than those of deoxy proto-CoMb, suggesting an increase in the electron spin density on the Co(II) ion upon the exchange of protoporphyrin IX with mesoprophyrin IX. Powder EPR spectra of these CoMbs, which were measured at S- and L-band microwave frequencies, exhibited well resolved 59Co hyperfine splittings and can be clearly interpreted by the use of the EPR parameters obtained from single crystal EPR measurements.

Cytotoxic properties of hydroxylamino- and amino-misonidazole, possible metabolic products of misonidazole, in hypoxic HeLa S3 cells

Misonidazole, a derivative of 2-nitroimidazole, has selective cytotoxic activity on hypoxic cells in addition to its radiosensitizing activity. This cytotoxicity is considered to be due to metabolic reduction of the drug. A possible metabolite seems to be hydroxylaminomisonidazole, an intermediate product derived via reduction of the nitro group. Authentic samples of hydroxylamino- and aminomisonidazole (a final reduction product) were synthesized and their cytotoxicity towards HeLa S3 cells was compared with that of misonidazole. After a 3-hr exposure to 1mM hydroxylaminomisonidazole under aerobic and hypoxic conditions, the surviving cell fractions were 0.18 and 0.0056, respectively. This represents a cytotoxicity five and 125 times greater, respectively, than that of misonidazole. Under the same conditions, aminomisonidazole showed no apparent cytotoxicity.

[Adsorption characteristics of organic solvent vapors on the fixed bed of activated carbon]

Many different sizes of activated carbon fixed beds are widely used for adsorption of organic solvent vapors and hazardous gases, such as air cleaners, gas masks and gas sampling tubes, but only limited information is available for the comprehensive relationship between adsorption characteristics of the fixed bed and practical factors; the amount of activated carbon, the gas flow rate, the vapor concentration and bed diameter. The authors investigated experimentally the effect of these factors on the adsorption zone length, the effective adsorption capacity and the breakthrough time. The following results were obtained; The adsorption zone length was approximately independent of the amounts of activated carbon packed in a column of a definite diameter. Therefore, the effective adsorption capacity increased with the increasing activated carbon amount, and the breakthrough time was nearly proportional to it. The adsorption zone length increased and the effective adsorption capacity reduced with the increasing gas flow rate. The adsorption zone length was little affected by the vapor concentration, but the effective adsorption capacity increased with the increasing concentration. In case of the same amount of activated carbon, the adsorption zone length, the effective adsorption capacity and the breakthrough time reduced with the increasing bed diameter.

The nucleotide sequences of 5S ribosomal RNAs from four Bryophyta-species

The nucleotide sequences of cytoplasmic 5S rRNA from four bryophytes, Marchantia polymorpha, Lophocolea heterophylla, Plagiomnium trichomanes and Anthoceros punctatus have been determined. These RNAs are 119 nucleotides long except for the Anthoceros RNA that has 118 nucleotides. Their sequences are highly similar to each other (91-99% identity) and are more related to those from seed plants (78-83% identity) than to those from green algae (61-73% identity).

The nucleotide sequences of 5S rRNAs from two red algae, Gracilaria compressa and Porphyra tenera

The nucleotide sequences of 5S rRNA from two red algae, Gracilaria compressa and Porphyra tenera have been determined. The two 5S rRNAs are fairly dissimilar to each other in their sequences (65% identity), although they are both composed of 121 nucleotides. Their secondary structures are generally of the eukaryotic with a prokaryotic characteristic. Judged from the 5S rRNA sequence data, the red algae are phylogenically distinct from green and brown algae, and they, Porphyra in particular, are evolutionally most ancient among the eukaryotes of which 5S rRNA sequence has been determined.

The nucleotide sequences of 5S rRNAs from a sea-cucumber, a starfish and a sea-urchin

The nucleotide sequences of 5S rRNA from three echinoderms, a sea-cucumber Stichopus oshimae, a starfish Asterina pectinifera and a sea-urchin Hemicentrotus pulcherrimus have been determined. These 5S rRNAs are all 120 nucleotides long. The echinoderm sequences are more related to the sequences of proterostomes animals such as mollusc, annelids and some others (87% identity on average) than to those of vertebrates (82% identity on average).

Castanospermine inhibits the processing of the oligosaccharide portion of the influenza viral hemagglutinin

Castanospermine (1,6,7,8-tetrahydroxyoctahydroindolizine) is a plant alkaloid that inhibits alpha- and beta-glucosidase in fibroblast extracts [Saul, R., Chambers, J. P., Molyneux, R. J., & Elbein, A. D. (1983) Arch. Biochem. Biophys. 221, 593-597]. In the present study, castanospermine also proved to be a potent inhibitor of glycoprotein processing by virtue of the fact that it inhibits glucosidase I. Thus, when influenza virus was raised in the presence of castanospermine, at 10 micrograms/mL or higher, 80-90% of the viral glycopeptides were susceptible to the action of endoglucosaminidase H, whereas in the normal virus 70% of the glycopeptides are resistant to this enzyme. The major oligosaccharide released by endoglucosaminidase H from castanospermine-grown virus migrated like a hexose10GlcNac on a calibrated Bio-Gel P-4 column. This oligosaccharide was characterized as a Glc 3 Man 7 GlcNAc on the basis of various enzymatic treatments, as well as by methylation analysis of the [2-3H]-mannose-labeled or [6-3H]galactose-labeled oligosaccharide. The presence of three glucose residues in the oligosaccharide was also confirmed by periodate oxidation studies of the [6-3H]galactose-labeled hexose10GlcNAc. Castanospermine did not inhibit the incorporation of [3H]leucine or [14C]alanine into protein in MDCK cells at levels as high as 50 micrograms/mL. In addition, influenza virus produced in the presence of this alkaloid were fully infective and apparently produced in similar amounts to that of control cells, as determined by plaque counts. Castanospermine did, however, cause considerable changes in cell surface properties, since MDCK cells grown in 10 micrograms/mL castanospermine were able to bind twice as much [3H]concanavalin A as were control cells.

The nucleotide sequences of 5S rRNAs from two Annelida species, Perinereis brevicirris and Sabellastarte japonica, and an Echiura species, Urechis unicinctus

The nucleotide sequences of 5S rRNAs from two Annelida species, Perinereis brevicirris and Sabellastarte japonica, and an Echiura species, Urechis unicinctus have been determined. Their sequences are all 120 nucleotides long. The sequence similarity percents are 88% (Perinereis/Sabellastarte), 90% (Sabellastarte/Urechis) and 92% (Perinereis/Urechis), indicating that the Echiura is indistinguishable from the Annelida by their 5S rRNAs. The 5S rRNA sequences from the Annelida/Echiura are most related to those from the Nemertinea (87%), the Mollusca (87%) and the Rotifera (88%).

Nucleotide sequence of 5 S rRNA from gonads of a Japanese ascidian, Holocynthia roretzi

The nucleotide sequence of 5 S rRNa from gonads of an ascidian Holocynthia roretzi has been determined. The sequence is almost equally related to those of vertebrates and most of the multicellular animal groups. The secondary structure of this 5 S rRNA fits in with the general structural model for multicellular 5 S rRNA.