Peroxisomal isocitrate lyase of the n-alkane-assimilating yeast Candida tropicalis: gene analysis and characterization

A genomic DNA clone encoding isocitrate lyase, a key enzyme of the glyoxylate cycle and a peroxisomal enzyme of the n-alkane-assimilating yeast Candida tropicalis has been isolated with a cDNA probe from the yeast lambda EMBL library. Nucleotide sequence analysis of the genomic DNA clone disclosed that the region coding isocitrate lyase had a length of 1,650 base pairs, corresponding to 550 amino acids (61,602 Da). RNA blot analysis demonstrated that only one kind of mRNA (2 kb) supposed to be transcribed from this gene was present in the cells. A comparison of the amino acid sequences was made with the isocitrate lyase of castor bean, one of the glyoxysomal enzymes, and the enzyme of E. coli. The isocitrate lyases of C. tropicalis and castor bean had high homology, and the presence of some amino acid stretches conserved in all three enzymes suggests that these might be involved in the catalysis of the common reaction. There was an insertion common to the isocitrate lyases of C. tropicalis and castor bean, which is of interest concerning their evolution. In the C-terminal region, a characteristic sequence similar to that previously proposed as the import signal to peroxisomes was present.

Molecular cloning of smg p21B and identification of smg p21 purified from bovine brain and human platelets as smg p21B

We have previously purified smg p21 from bovine brain membranes and isolated its cDNA from a bovine brain cDNA library. In the present studies, we have performed extensive screening of the bovine brain cDNA library with the cloned smg p21 cDNA as a probe and isolated another cDNA encoding a protein highly homologous to smg p21. The proteins encoded by the previously and newly isolated cDNAs are designated as smg p21A and -B, respectively. Since the partial amino acid sequences determined previously from the smg p21 purified from bovine brain were identical with the common amino acid sequences between smg p21A and -B, we have further sequenced smg p21 and identified it as smg p21B. We have also further sequenced the smg p21 purified from human platelet membranes and identified it as smg p21B. Amino acid sequence analysis indicates that smg p21A is identical with the rap1A and Krev-1 proteins and smg p21B is identical with the rap1B protein.

Periosteal microvasculature in the dog alveolar process

Most periodontal surgery has been performed on the basis of the regenerating capacity of the periosteum. Recently it has been pointed out that the blood supply is important to the osteogenic and fibrogenic activity of the periosteum. The purpose of the present study was three-dimensional observation of blood vessels distributed within the gingival periosteum and the periosteum beneath the alveolar mucosa of adult mongrel dogs. Corrosion cast specimens of vessels were observed from three directions: mucosal side, bone side, and horizontal cut surface. It was revealed that the plexus distributed in the periosteum of the gingiva formed a coarse network structure, which consisted mainly of arterioles and venules. In contrast, in the periosteum of the alveolar mucosa, a dense network structure consisting of arterioles, capillaries, and venules formed a vascular bed. Thus, the mucogingival junction was easily located even in the plexus of periosteum which was distributed beneath the gingiva and the alveolar mucosa, suggesting that the difference in tissue specificity was reflected in the plexus of the periosteum.

[Relationship between clinical findings and subgingival microbial flora in periodontitis (2)]

The purpose of this study was to examine the relationship between clinical findings and subgingival relationship between clinical findings and subgingival microbial flora in periodontitis at the first medical examination and after initial preparation. The results obtained were as follows: 1. Clinical findings with the exception of plaque index showed improvement after initial preparation in comparison with the first medical examination. 2. In phase contrast microscopy, both total bacteria and incidence of spirochetes and motile rods decreased after initial preparation in comparison with the first medical examination. 3. Clinical findings with the exception of plaque index were related to the total bacteria and proportional distribution of spirochetes and motile rods in periodontal pockets, observed in phase contrast microscopy. 4. Total bacteria and proportional distribution of black-pigmented Bacteroides in periodontal pockets decreased after initial preparation in comparison with the first medical examination.

Identification of a gene conferring resistance to zinc and cadmium ions in the yeast Saccharomyces cerevisiae

A DNA fragment conferring resistance to zinc and cadmium ions in the yeast Saccharomyces cerevisiae was isolated from a library of yeast genomic DNA. Its nucleotide sequence revealed the presence of a single open reading frame (ORF; 1326 bp) having the potential to encode a protein of 442 amino acid residues (molecular mass of 48.3 kDa). A frameshift mutation introduced within the ORF abolished resistance to heavy metal ions, indicating the ORF is required for resistance. Therefore, we termed it the ZRC1 (zinc resistance conferring) gene. The deduced amino acid sequence of the gene product predicts a rather hydrophobic protein with six possible membrane-spanning regions. While multiple copies of the ZRC1 gene enable yeast cells to grow in the presence of 40 mM Zn2+, a level at which wild-type cells cannot survive, the disruption of the chromosomal ZRC1 locus, though not a lethal event, makes cells more sensitive to zinc ions than are wild-type cells.

[Relationship between clinical findings and subgingival microbial flora in periodontitis (1)]

The purpose of this study was to examine the relationship between clinical findings and subgingival microbial flora in periodontitis. The results obtained were as follows: 1. In a phase-contrast microscopic study, no correlation was found between the clinical findings, total bacteria or proportional distribution of spirochetes or motile rods in the periodontal pocket. 2. Anaerobic incubation revealed no correlation between clinical findings, total bacteria or proportional distribution of black-pigmented Bacteroides in the periodontal pocket.

Immunocytochemical demonstration of amelogenins and enamelins secreted by ameloblasts during the secretory and maturation stages

Rabbit polyclonal antibodies against bovine amelogenins and enamelins which did not show any cross-reaction were raised, and ultrathin sections of rat incisors were examined by the protein A-gold and ABC methods. The immunoreactivity of amelogenins was found in dense granules in the intercellular spaces between preameloblasts, and later over the fine- and coarse-textured material. The immunoreactivity was present over the cell organelles associated with the secretory pathway, as well as pale and dark lysosomes of the presecretory and secretory ameloblasts. Here the enamel was immunolabeled in the intercrystal spaces. The immunoreactivity in multivesicular bodies was stronger in preameloblasts than in secretory ameloblasts. In the region of second ruffle-ended ameloblasts at the maturation stage, the immunolabeling was intense in the ruffled-border, but in the rough endoplasmic reticulum and Golgi apparatus, the immunolabeling was much weaker than at the secretory stage. The immunolabeling for enamelins showed essentially the same intracellular topographical pattern as that for amelogenins by the secretory stage, but was weaker. The immunoreactivity was found mainly attached to the enamel crystals. Double immunostaining of amelogenins and enamelins revealed that both immunoreactivities were present over the same cell organelles associated with secretion and lysosomal systems. It is suggested that the presecretory and secretory ameloblasts are actively involved in the secretion, degradation and resorption of enamel proteins, and that multivesicular bodies and lysosomes in the cells take part in these processes. Ameloblasts are considered to be related to the synthesis of enamelins.

[Histopathological and clinical studies of acute necrotizing ulcerative gingivitis and evaluation of treatment]

We report the clinical data, light and electron microscopic findings, therapy and clinical course of three cases treated for acute necrotizing ulcerative gingivitis. The following results were obtained. 1. An ulcerous lesion was observed in the gingiva of all three cases, with case I also showing a depressed lesion in the ulcerous region. 2. In all three cases, the gingival sections displayed ulceration and showed fibrin deposition and neutrophil infiltration on the surface of the ulcerous region. Congested blood vessels and neutrophil infiltration also were observed in the connective tissue beneath the ulcerous region. 3. Many microorganisms, fibrin, cell debris, and enlarged intercellular spaces of the epithelium were seen on the surface on the ulcerous region. 4. Localized treatment, mainly plaque control, was found to be effective clinically and histopathologically.

[Effectiveness of local delivery of ofloxacin using controlled-release strips (PT-01) in periodontal patients. Part 2. Successive delivery system and combination with scaling]

Four different sites were randomly selected in each periodontal patient and divided into four group: PT-01-treated site (A), PT-01 treatment combined with scaling (S + A), placebo-treated site (P) and placebo treatment combined with scaling (S + P). PT-01 and the placebo were applied to the periodontal pocket weekly on days 0 to 28, and clinical and microbiological evaluations were made. The results obtained were as follows: 1. Weekly changes in plaque index, plus discharge and mobility of the tooth were not observed in any group. 2. In gingival index, bleeding on probing, pocket depth and gingival crevicular fluid, significant improvement was found in A in comparison with P and in S + A in comparison with S + P. 3. In total number of subgingival bacteria and in the ratio of motile rods and spirochetes to the total number of bacteria, significant reduction was found in A in comparison with P and in S + A in comparison with S + P.

[Effectiveness of local delivery of ofloxacin using controlled-release strips (PT-01) in periodontal patients. Part 1. PT-01 application among treatment plans for periodontal disease]

Three different sites which have more than 5 mm pocket were randomly selected in each periodontal patient and were divided into three groups: PT-01 treated site, placebo treated site and control site. After application of either PT-01 or placebo twice for two weeks, subgingval scaling and root planing were performed. Then PT-01 and the placebo were applied weekly to the periodontal pocket for four weeks and clinical and microbiological evaluations were made. The results obtained were as follows: 1. On clinical evaluation, significant improvement was found in the PT-01 treated site in comparison with the placebo treated and/or control site. 2. On microbiological evaluation, slight improvement was found in the PT-01 treated site, whereas there was no significant difference among the three sites.

Identification of an upstream activating sequence and an upstream repressible sequence of the pyruvate kinase gene of the yeast Saccharomyces cerevisiae

To clarify carbon source-dependent control of the glycolytic pathway in the yeast Saccharomyces cerevisiae, we have initiated a study of transcriptional regulation of the pyruvate kinase gene (PYK). By deletion analysis of the 5'-noncoding region of the PYK gene, we have identified an upstream activating sequence (UASPYK1) located between 634 and 653 nucleotides upstream of the initiating ATG codon. The promoter activity of the PYK 5'-noncoding region was abolished when the sequence containing the UASPYK1 was deleted from the region. Synthetic UASPYK1 (26mer), in either orientation, was able to restore the transcriptional activity of UAS-depleted mutants when placed upstream of the TATA sequence located at -199 (ATG as +1). While the UASPYK1 was required for basal to intermediate levels of transcriptional activation, a sequence between -714 and -811 was found to be necessary for full activation. On the other hand, a sequence between -344 and -468 was found to be responsible for transcriptional repression of the PYK gene when yeast cells were grown on nonfermentable carbon sources. This upstream repressible sequence also repressed transcription, although to a lesser extent, when glucose was present in the medium. The possible mechanism for carbon source-dependent regulation of PYK expression through these cis-acting regulatory elements is discussed.

Tissue-specific expression of a novel GTP-binding protein (smg p25A) mRNA and its increase by nerve growth factor and cyclic AMP in rat pheochromocytoma PC-12 cells

We have purified a novel GTP-binding protein, designated as the smg-25A protein (smg p25A), from bovine brain membranes and determined its primary structure. In the present studies, the smg-25A mRNA levels in various tissues have been studied. The 1.6-kilobase smg-25A mRNA is detected in rat brain by Northern blot analysis. This mRNA is not detected in other rat tissues including thymus, lung, heart, liver, small intestine, kidney, and skeletal muscle. The 1.6-kilobase smg-25A mRNA is also detected in bovine adrenal medulla but not in the cortex. Moreover, this mRNA is detected in rat pheochromocytoma PC-12 cells and its level increases after differentiation of the cells into sympathetic neuron-like cells in response to nerve growth factor or dibutyryl cyclic AMP. This mRNA level does not increase in response to 12-O-tetradecanoylphorbol-13-acetate incapable of inducing differentiation. These results suggest that the smg-25A gene is specifically expressed in nerve tissues and that smg p25A plays a role in some neuronal functions.

Characterization of very low density lipoprotein from Watanabe heritable hyperlipidemic rabbits

We investigated the properties of very low density lipoprotein (VLDL) from two types of Watanabe heritable hyperlipidemic (WHHL) rabbits: one with a high incidence of coronary atherosclerosis (type 1), and the other with a low incidence (type 2). When incubated with mouse peritoneal macrophages, VLDL from type 1 WHHL rabbit (type 1-VLDL) stimulated cholesteryl ester synthesis 10.5-fold more than VLDL from the type 2 WHHL rabbit (type 2-VLDL) did. Moreover, a similar difference was seen in the stimulation of cholesteryl ester synthesis in peritoneal macrophages isolated from the WHHL rabbits. The mass ratios of cholesterol to protein in type 1- and type 2-VLDL were 5.69 and 2.05, respectively. Agarose gel electrophoresis of type 1-VLDL showed beta mobility, and that of type 2-VLDL showed pre-beta mobility. No difference was seen between the sizes of VLDL particles of the two types. The amount of apolipoprotein E in type 1-VLDL was greater than that in type 2-VLDL. In conclusion, the difference between type 1 and type 2 WHHL rabbits is at least partly due to the presence in type 1 animals of VLDL particles rich in cholesteryl esters and apolipoprotein E, particles which are very similar to beta-VLDL in conformation.

A novel small molecular weight GTP-binding protein with the same putative effector domain as the ras proteins in bovine brain membranes. Purification, determination of primary structure, and characterization

In the present studies, we have purified a novel small Mr GTP-binding protein, designated as smg p21, to near homogeneity from bovine brain crude membranes, isolated the complementary DNA (cDNA) of this protein from a bovine brain cDNA library, determined the complete nucleotide and deduced amino acid sequences, and characterized the kinetic properties. The cDNA of smg p21 has an open reading frame encoding a protein of 184 amino acids with a calculated Mr of 20,987. The Mr of purified smg p21 is estimated to be about 22,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Homology search indicates that smg p21 is a novel protein with the consensus amino acid sequences for GTP/GDP-binding and GTPase domains but shares about 55% amino acid sequence homology with the human c-Ha-ras protein. Moreover, smg p21 has the same putative effector domain as the Ha-, Ki-, and N-ras proteins at the same position and the same consensus C-terminal sequence as in these ras proteins. Consistent with these structural properties, smg p21 binds specifically [35S] guanosine 5'-(3-O-thio)triphosphate (GTP gamma S), GTP, and GDP with a Kd value for GTP gamma S of about 40 nM. smg p21 binds about 0.7 mol of GTP gamma S/mol of protein. [35S]GTP gamma S-binding to smg p21 is inhibited by pretreatment with N-ethylmaleimide.smg p21 hydrolyzes GTP to liberate Pi with a turnover number of about 0.007 min-1. These kinetic properties of smg p21 are similar to those of the c-ras proteins. These results suggest that smg p21 is a novel GTP-binding protein exerting action(s) similar or antagonistic to that (those) of the ras proteins.

[A study of ultrasonic scaler. The effect of the different frequencies of the ultrasonics in the experimental calculus removal and roughness of the metallic plate after scaling]

In an attempt to determine how the degree of the experimental calculus removal on the metallic plate and its roughness after scaling would be affected by ultrasonics under high or low frequency, quantitative measurement and morphological observation were made. The results obtained were as follows: 1. On the calculus removal, larger effect was obtained by high frequency unit than low frequency. 2. On the roughness of the metallic plate after scaling, larger defect was observed by high frequency unit than low frequency. 3. Scanning electron microscopically, strip like defects were observed under low frequency unit, while exfoliation of the metallic plate in addition to the strip like defects were observed under high frequency.

Purification and characterization of c-Ki-ras p21 from bovine brain crude membranes

In the present studies, we attempted to purify the native molecular forms of the c-ras proteins (c-ras p21s) from bovine brain crude membranes and separated at least three GTP-binding proteins (G proteins) cross-reactive with the antibody recognizing all of Ha-, Ki-, and N-ras p21s. Among them, one G protein with a Mr of about 21,000 was highly purified and characterized. The Mr 21,000 G protein bound maximally about 0.6 mol of [35S]guanosine 5'-(3-O-thio)triphosphate (GTP gamma S)/mol of protein with a Kd value of about 30 nM. [35S]GTP gamma S-binding to Mr 21,000 G protein was inhibited by GTP and GDP, but not by other nucleotides such as ATP, UTP, and CTP. [35S]GTP gamma S-binding to Mr 21,000 G protein was inhibited by pretreatment with N-ethylmaleimide. Mr 21,000 G protein hydrolyzed GTP to liberate Pi with a turnover number of about 0.01 min-1. Mr 21,000 G protein was not copurified with the beta gamma subunits of the G proteins regulatory for adenylate cyclase. Mr 21,000 G protein was not recognized by the antibody against the ADP-ribosylation factor for Gs. The peptide map of Mr 21,000 G protein was different from those of the G proteins with Mr values of 25,000 and 20,000, designated as smg p25A and rho p20, respectively, which we have recently purified from bovine brain crude membranes. The partial amino acid sequence of Mr 21,000 G protein was identical with that of human c-Ki-ras 2B p21. These results indicate that Mr 21,000 G protein is bovine brain c-Ki-ras 2B p21 and that c-Ki-ras 2B p21 is present in bovine brain membranes.

Construction of a new shuttle expression vector for Bacillus subtilis and Escherichia coli by using a polycistronic system

A shuttle vector has been constructed by fusing the Bacillus subtilis trimethoprim-resistance-carrying (TpR) plasmid pNC601 with the Escherichia coli plasmid pBR322. The resultant plasmid pNBL1 can replicate in both B. subtilis and E. coli, conferring Tp resistance on both cells and ampicillin resistance (ApR) on E. coli. The B. subtilis dihydrofolate reductase operon (dfr) on pNC601 and therefore on pNBL1 consists of the thymidylate synthase B gene (thyB) and the TpR-dihydrofolate reductase gene lacking the C-terminal seven codons (designated as drfA' as compared with the complete dfrA gene). A direct-expression vector pNBL3 has been constructed by inserting synthetic oligodeoxynucleotides containing a Bacillus ribosome-binding site (RBS) and the ATG codon downstream from dfrA' on pNBL1. When the E. coli lacZ gene was placed downstream from the dfrA' gene in pNBL3, efficient synthesis of beta-galactosidase was observed in both cells, showing that the polycistronic expression system is suitable for directing expression of heterologous genes. Translational efficiency of the lacZ gene on pNBL3 was further examined in B. subtilis by changing the sequence upstream from lacZ. Unlike the results previously reported [Sprengel et al., Nucleic Acids Res. 13 (1985) 893-909], when RBS was present, the high level of lacZ expression was preserved irrespective of spacing between the stop codon of the upstream dfrA' gene and the start codon of the downstream lacZ gene. However, in the absence of RBS, the spacing between both genes affected lacZ expression. That is, translational coupling of dfrA'-lacZ was observed, although the translational efficiency was very low.

Nucleotide and deduced amino acid sequences of a GTP-binding protein family with molecular weights of 25,000 from bovine brain

We have purified a novel GTP-binding protein (G protein) with a Mr of about 24,000 to homogeneity from bovine brain membranes (Kikuchi, A., Yamashita, T., Kawata, M., Yamamoto, K., Ikeda, K., Tanimoto, T., and Takai, Y. (1988) J. Biol. Chem. 263, 2897-2904). In the present studies, we have isolated and sequenced the cDNA of this G protein from a bovine brain cDNA library using oligonucleotide probes designed from the partial amino acid sequences. The cDNA of the G protein has an open reading frame encoding a protein of 220 amino acids with a calculated Mr of 24,954. This G protein is designated as the smg-25A protein (smg p25A). The amino acid sequence deduced from the smg-25A cDNA contains the consensus sequences of GTP-binding and GTPase domains. smg p25A shares about 28 and 44% amino acid homology with the ras and ypt1 proteins, respectively. In addition to this cDNA, we have isolated two other homologous cDNAs encoding G proteins of 219 and 227 amino acids with calculated Mr values of 24,766 and 25,975, respectively. These G proteins are designated as the smg-25B and smg-25C proteins (smg p25B and smg p25C), respectively. The amino acid sequences deduced from the three smg-25 cDNAs are highly homologous with one another in the overall sequences except for C-terminal 32 amino acids. Moreover, three smg p25s have a consensus C-terminal sequence, Cys-X-Cys, which is different from the known C-terminal consensus sequences of the ras and ypt1 proteins, Cys-X-X-X and Cys-Cys, respectively. These results together with the biochemical properties of smg p25A described previously indicate that three smg p25s constitute a novel G protein family.

Purification and characterization of a GTP-binding protein with a molecular weight of 20,000 in bovine brain membranes. Identification as the rho gene product

We have determined that there are at least six GTP-binding proteins (G proteins) with Mr values between 20,000 and 25,000 in the crude membrane fraction of bovine brain and have purified one of them with a Mr of about 24,000 (24K G) to near homogeneity (Kikuchi, A., Yamashita, T., Kawata, M., Yamamoto, K., Ikeda, K., Tanimoto, T., and Takai, Y. (1988) J. Biol. Chem. 263, 2897-2904). In this study, we have purified another G protein with a Mr of about 20,000 (20K G) to near homogeneity and have characterized it. 20K G bound maximally about 1.0 mol of [35S]guanosine 5'-(3-O-thio)triphosphate (GTP gamma S)/mol of protein, with a Kd value of about 50 nM. [35S]GTP gamma S binding to 20K G was inhibited by GTP and GDP, but not by other nucleotides such as ATP, UTP, and CTP; it was also inhibited by pretreatment with N-ethylmaleimide. 20K G hydrolyzed GTP to liberate Pi, with a turnover number of about 0.01 min-1, and was not copurified with the beta gamma subunits of the regulatory G proteins of adenylate cyclase. 20K G was not recognized by the antibody against the ADP-ribosylation factor for the stimulatory regulatory G protein of adenylate cyclase. Peptide map analysis showed that 20K G was not a proteolytic product of 24K G. The partial amino acid sequence of 20K G was almost identical with that deduced from the rho gene. The amino acid composition of 20K G was similar to that of the rho gene product. These results suggest that 20K G is the rho gene product and that this G protein is present in bovine brain membranes.