cDNA cloning and tissue-specific expression of the gene encoding human adenylate kinase isozyme 2

We isolated two kinds of cDNAs encoding human adenylate kinase (AK) isozyme 2 from a HeLa cell cDNA library using bovine AK2 cDNA as a probe. Nucleotide sequencing revealed that the cDNAs encoded 239- and 232-amino acid proteins with deduced molecular mass of 26.5 (AK2A) and 25.6kDa (AK2B), respectively. Northern blot analysis demonstrated that AK2 mRNA is strongly expressed in liver, heart, skeletal muscle and pancreas, and moderately in kidney, placenta and brain, and weakly in lung. However, Western blot analysis showed that AK2 protein was present in large amounts in liver, heart, kidney, and in a small amount in lung, and undetectable in brain and skeletal muscle. These results suggested the presence of the tissue-specific gene-expression including post-transcriptional regulation in expression of the AK2 gene.

[Antimicrobial activities of cefcapene against clinical isolates from respiratory tract infections of outpatients]

In order to evaluate antimicrobial activity of cefcapene (CFPN), minimum inhibitory concentrations (MICs) of CFPN and reference drugs were determined against clinical isolates from respiratory tract infection of out patients that were obtained in our laboratory from January to June of 1997. The results are summarized as follows; 1. The MIC90 of CFPN against penicillin (PC)-susceptible Streptococcus pneumoniae (PSSP) was equal to those of benzylpenicillin (PCG), ampicillin (ABPC) and cefditoren (CDTR), and was lower than those of cefaclor (CCL), cefdinir (CFDN) and erythromycin (EM). 2. The MIC90 of CFPN against PC-intermediate S. pneumoniae (PISP)/PC-resistant S. pneumoniae (PRSP) was equal to that of CDTR, and was lower than those of PCG, ABPC, CCL, CFDN and EM. CFPN showing strong antimicrobial activities against PISP. 3. CFPN showed strong antimicrobial activities against beta-lactamase producing and non-producing Haemophilus influenzae. The MIC90 of CFPN was stronger than those of ABPC, CCL, CFDN and EM, and was approximately equal to that of CDTR. CFPN also showed strong antimicrobial activities against strains which did not produce any beta-lactamase and were resistant to CCL with MIC of > or = 25 micrograms/ml. 4. Antimicrobial activities of CFPN against Moraxella subgenus Branhamella catarrhalis was stronger than that of ABPC and CCL, though the MIC90 of CFPN was rather high, 3.13 micrograms/ml. 5. CFPN showed strong antimicrobial activities against PISP and beta-lactamase producing H. influenzae, and also against the CCL-resistant H. influenzae indicative mutations of penicillin-binding proteins (PBPs). From those results, cefcapen-pivoxil was found to be clinically effective against community acquired respiratory tract infection.

Mechanism of mitochondrial import of adenylate kinase isozymes

Adenylate kinase (AK) is a ubiquitous enzyme that contributes to the homeostasis of the cellular adenine nucleotide composition. Three isozymes, AK1, AK2, and AK3, have so far been characterized in vertebrates. They are located in different tissues, while their primary and tertiary structures are similar. Among them, AK2 and AK3 are located in mitochondria, but unlike most mitochondrial proteins, both proteins lack a cleavable presequence. In this study, we first confirmed that AK2 is distributed in liver cells in both the cytosol and the intermembrane space of mitochondria, while AK3 is localized exclusively in the mitochondrial matrix. Next, we analyzed the process of import of AK2 and AK3 by incubating isolated rat mitochondria with proteins that were synthesized in a reticulocyte lysate translation system. The results indicated that both AK2 (an intermembrane-space-targeting protein) and AK3 (a matrix-targeting protein) require an inner membrane electrochemical potential for their import. This finding for AK2 is in contrast with those of other noncleavable intermembrane-space-targeting proteins such as cytochrome c and cytochrome c heme lyase, which do not require the membrane potential for their import. In the transport process, AK2 and AK3 competed with the adrenodoxin precursor, which is imported into the matrix through a mechanism common to other mitochondrial matrix proteins. Thus, AK2 and AK3 were thought to be translocated into mitochondria through the same pathway as that for most mitochondrial protein precursors. Neither AK2, that was previously synthesized in reticulocyte lysates, nor AK2, that was purified from an Escherichia coli overexpression system, was imported into mitochondria in a post-translational import manner. In contrast, AK3 was imported into mitochondria after completion of protein synthesis. Thus, the import of AK2 is likely to be co-translational, and the co-translational import mechanism might contribute to the bi-topological distribution of AK2 in both the cytosol and mitochondria.

[Antimicrobial activities of clindamycin against clinical isolated Streptococcus pneumoniae]

We investigated antimicrobial activity of clindamycin (CLDM) against clinically isolated Streptococcus pneumoniae in 1996. The results are summarized as follows; 1. The detection frequencies of macrolides (MLs)-resistance against penicillin (PC)-susceptible S. pneumoniae (PSSP) was 48.0% and those against PC-intermediate S. pneumoniae (PISP)/ PC-resistant S. pneumoniae (PRSP) was 92.0%. 2. It was found that the ratio of MLs-inducible resistant strains of PSSP was 24.6% and that of PISP/PRSP was 66.0%. MLs-constitutive resistant strains of PSSP accounted for 24.0% and that of PISP/PRSP for 26.0%. MLs-constitutive resistant strains was relatively frequent in PSSP and MLs-inducible resistant strains was frequent in PISP/PRSP. 3. CLDM showed strong antimicrobial activity against MLs-inducible resistant strains. The MIC70 of CLDM against PSSP was < or = 0.025 microgram/ml and that against PISP/PRSP was 0.1 microgram/ml. From these results, it was suggested that CLDM is effective against the infection of PISP/PRSP where the detection frequency of MLs-inducible strains was high. 4. Antimicrobial activity of CLDM was found to be strong against MLs-inducible resistant strains, but to be weak against MLs-constitutive resistant strains. When S. pneumoniae is detected, susceptibility of the strain to CLDM should be examined.

[The drug susceptibility pattern of the presumed etiologic agents of infectious enteritis including verotoxin-producing Escherichia coli O-157]

The drug susceptibility patterns were investigated for verotoxin-producing Escherichia coli (VTEC) including O-157, Salmonella spp., Vibrio parahaemolyticus and Campylobacter jejuni subsp. jejuni that were obtained in and after July 1996. The results are summarized as follows; 1. We found highly resistant strains of VTEC to tetracycline (TC) and ampicillin (ABPC). Minimum inhibitory concentrations (MIC) of some of the drugs against VTEC in an aerobic condition were significantly different from those in an anaerobic condition. For example, aerobic.anaerobic MIC ranges of the drugs tested were as follows: chroramphenicol (CP): 1.56-3.13 micrograms/ml.0.78-1.56 micrograms/ml, TC: 1.56-> 100 micrograms/ml.0.78-> 100 micrograms/ml, minocycline (MINO): 1.56-12.5 micrograms/ml.0.78-3.13 micrograms/ml, kanamycin (KM): 3.13-6.25 micrograms/ml.25-100 micrograms/ml, fosfomycin (FOM): 3.13-25 micrograms/ml.0.78-6.25 micrograms/ml, norfloxacin (NFLX): < or = 0.025-0.2 microgram/ml.< or = 0.025-0.2 microgram/ml, ABPC: 1.56-> 100 micrograms/ml.0.78-> 100 micrograms/ml and cefaclor (CCL): 1.56-25 micrograms/ml.56-12.5 micrograms/ml. MICs of CP and tetracyclines (TCs) in an anaerobic condition were lower by twofold and the MIC of FOM was lower by fourfold, but the variabilities of MIC-ranges of NFLX, ABPC and CCL were small. The MIC of KM was high. 2. We observed that some of Salmonella spp. were highly resistant to CP, TCs and MINO, and some were moderately resistant to NFLX. 3. The detection frequency of TC-resistant strains and NFLX-insensitive or resistant strains were high among C. jejuni subsp. jejuni. 4. Strains of V. parahaemolyticus and C. jejuni subsp. jejuni were mostly resistant to ABPC and CCL, MICs of which were in high ranges. 5. Fecal concentrations in MINO, KM, FOM and NFLX reported in literatures are high enough to have some antimicrobial activities, leed dose of ABPC and CCL are quite low.

[Antimicrobial activities of clarithromycin against recent obtained clinical isolates]

In order to evaluate antimicrobial activities of clarithromycin (CAM), minimum inhibitory concentrations (MICs) of CAM and control drugs were determined against clinical isolates that were obtained from outpatients in 1994 and 1996. The results are summarized as follows; 1. It was not showed that CAM-resistant strains were increasing among Staphylococcus spp., beta-streptococci, Moraxella subgenus Branhamella catarrhalis, Haemophilus influenzae, Bordetella pertussis, Campylobacter jejuni subsp. jejuni, Chlamydia trachomatis and Mycoplasma pneumoniae. It appeared that resistances to CAM and macrolides (MLs) were increasing among Streptococcus pneumoniae and Peptostreptococcus spp. 2. The drug susceptibility patterns to MLs were similar and detection frequencies of induced resistant strains that were resistant to only 14-membered ring MLs including CAM and constitutive resistant strains that were resistant to 14 and 16-membered ring MLs were high among Streptococcus pneumoniae and Peptostreptococcus spp. It appears that MLs-resistance systems are linked to each other, and that this was a cause of increasing MLs-resistance among these bacterial species. 3. Notwithstanding of antibiotic resistance problems, CAM is still useful since it maintains strong antimicrobial activities against M. (B.) catarrhalis, B. pertussis, C. jejuni subsp. jejuni, C. trachomatis and M. pneumoniae, and it controls arginate producing abilities of mucoide strains of Pseudomonas aeruginosa.

[Clinical and bacteriological effects of cefetamet pivoxil against community-acquired respiratory tract infections. Part II]

We investigated clinical and bacteriological effects of cefetamet pivoxil (CEMT-PI) in community-acquired respiratory tract infections and obtained the following findings. That method was approximately equal to that of investigation in 1994. 1. Of the 431 respiratory tract infection cases that were treated with CEMT-PI according to a same protocol at a total of 41 institutions in Tokyo, Kanagawa-ken, Saitama-ken and Chiba-ken from January to the beginning of March 1996. Outpatients accounted for 98.1% of the subjects. Regarding genders to patients, slightly more females (52.6%) than males were included. Diagnoses given to these patients included pharyngo-laryngitis (53.5%), tonsillitis (20.4%) and acute bronchitis (19.1%). 2. We investigated clinical efficacy rates (the ratio of those excellent + good) classified by diseases. The improvement rates of pharyngo-laryngitis, tonsillitis and acute bronchitis were more than 85.0%. Other cases were small in number. That of chronic bronchitis-acute increasing change for the worse was 66.7%, pneumonia was 50.0% and bronchiectasis infection was 16.7%. It was not studied that clinical efficacy rates among those who were treated with 1 CEMT-PI tablet twice and among those who were given 2 tablets twice were significant level. 3. For the bacteriological study, a written material describing the method of collecting specimens, storage and transport in detail was distributed to the above mentioned institutions. The isolation and identification of suspected causative bacteria, determination of minimum inhibitory concentrations (MICs) and investigation of beta-lactamase production were conducted all together at section of studies, Tokyo Clinical Research Center. Suspected causative bacteria were detected from 274 (63.6%) cases. They included 88 strains of Haemophilus influenzae, 47 strains of Streptococcus pneumoniae, 42 strains of Streptococcus pyogenes, 20 strains of Moraxella subgenus Branhamella catarrhalis and 17 strains of Klebsiella pneumoniae subsp. pneumoniae. Suspected causative bacteria classified by diseases were S. pyogenes (tonsillitis), S. pneumoniae (acute bronchitis and secondary infection of chronic respiratory infection) and H. influenzae (pharyngo-laryngitis), and the detection frequency of those was high. The clinical efficacies (the ratio of improvement) classified by suspected causative bacteria were 84.4% against organism that was indicating CEMT and were 69.2% against organism that was not indicating CEMT.

Avidity of technetium 99m glucarate for the necrotic myocardium: in vivo and in vitro assessment

BACKGROUND

Similar to other 99mTc-based infarct-avid agents, 99mTc-glucarate localizes in myocardial infarcts. Whether severely ischemic viable myocytes sequester 99mTc-glucarate is uncertain. To assess the infarct specificity, in vitro and in vivo studies were performed.

METHODS AND RESULTS

H9C2 embryonic rat cardiocytes cultured under normoxia (N) or hypoxia (H) for 24 hours in 7.5 muCi 99mTc-glucarate were compared with necrotic cardiocytes. Mean H/N ratio (3.0 +/- 0.004, mean +/- SD) was significantly less than that of the necrotic/N ratio (39.9 +/- 6.5, p < 0.01). Reperfused myocardial infarction (MI) in 4 dogs confirmed by 201Tl (0.5 to 1.0 mCi) scintigraphy were imaged serially with simultaneously injected mixture of 99mTc-glucarate and 111In-antimyosin Fab. Infarcts were detected scintigraphically within 4 to 10 minutes with 99mTc-glucarate. 111In-antimyosin required more than 1 hour. Myocardial distribution at 5 hours showed a direct correlation between 99mTc-glucarate and 111In-antimyosin uptake (r = 0.99, p < 0.0001). Both 99mTc-glucarate (r = -0.777, p < 0.0001) and 111In-antimyosin (r = -0.775, p < 0.0001) were inversely related to 201Tl distribution.

CONCLUSIONS

The near perfect correlation between 99mTc-glucarate and 111In-antimyosin uptake (r = 0.99) in reperfused canine MI and the insignificant glucarate uptake by viable cardiocytes in vitro attest to the avidity of 99mTc-glucarate for the necrotic myocardium and favor its use as a specific early marker of myocyte necrosis in acute MI.

Wild-type p53 gene-induced morphological changes and growth suppression in hepatoma cells

The human hepatocellular carcinoma (HCC) cell line, HLF, expresses only mutant-type p53 (mt-p53), which has an amino acid substitution at the 244th residue from glycine to alanine. HLF cells were transfected with wild-type p53 (wt-p53) cDNA construct pC53-SN3, mt-p53 cDNA construct pC53-SCX [which differs by a single nucleotide, resulting in alanine instead of valine at the 143rd residue in p53 (p53-143)], or pCMV-Neo-Bam, as a control, by a liposome method. After G418 selection, three wt-p53 stable transformants (WT), four mt-p53 transformants (MT), and three control vector transformants (VT) were obtained. We analyzed the cell growth and morphological changes of these transformants under different culture conditions [fetal calf serum (FCS), 10%, 1%, and 0%]. Whereas no difference from control in the growth rate and morphology was observed under the 10% FCS conditions, serum starvation induced remarkable phenotypical changes in all three WTs, but not in the other transformant. Corresponding to these phenotypical changes, the transcriptional activity of wt-p53 was increased more than nine fold. These results indicated that serum starvation would induce wt-p53 biological function, which is tightly linked to morphological changes and growth suppression. To induce these changes, the introduction of the wt-p53 gene itself was not sufficient, and additional triggering, i.e., serum starvation, was indispensable.

Targeting human breast tumour in xeno-grafted SCID mice with 99Tcm-glucarate

99Tcm-glucarate accumulation in human mammary BT-20 tumours hosted in severe combined immune deficiency (SCID) mice was compared to 111In-monoclonal antibody 103D2-F(ab')2, 99Tcm-methoxyisobutyl isonitrile (99Tcm-MIBI) and 99Tcm-diethylenetriamine pentaacetate (99Tcm-DTPA). The intracellular tumour distribution of 99Tcm-glucarate was also determined. SCID mice injected with a mixture of 99Tcm-glucarate and 111In-103D2-F(ab')2 were imaged serially up until 24 h. Computer planimetered tumour-to-blood activity (in the heart) ratios (T/BH) to 8 h were significantly greater for 99Tcm-glucarate than 111In-103D2. The mean (+/-S.D.) tumour-to-blood ratio (T/B) from biodistribution was 1.21 +/- 0.31 and 0.35 +/- 0.06 (P < 0.0001) at 5 h, and 1.526 +/- 0.29 and 0.75 +/- 0.2 (P < 0.0001) at 8 h, for 99Tcm-glucarate and 111In-103D2 respectively. At 24 h, T/B for 111In-103D2 (1.76 +/- 0.22) exceeded that of 99Tcm-glucarate (1.44 +/- 0.2, P = 0.01). 99Tcm-glucarate uptake in the tumours at 5 h (1.133 +/- 0.25 %ID g-1) and 8 h (1.213 +/- 0.23 %ID g-1) was significantly greater than that of 99Tcm-MIBI (0.340 +/- 0.09, P = 0.0002; 0.220 +/- 0.04, P = 0.0001) and 99Tcm-DTPA (0.091 +/- 0.03, P < 0.0002; 0.016 +/- 0.01, P < 0.0001) respectively. Intracellular tumour distribution of 99Tcm-glucarate was 50.91 +/- 6.55% in the nuclear fraction, 34.34 +/- 2.88% in the cytoplasmic fraction and 14.75 +/- 7.66% in the mitochondrial fraction. Thus glucarate may provide a 99Tcm-based mammary tumour imaging modality for visualization of tumours very quickly after tracer administration with maximal targeting in the nuclei of the tumour cells.

Increased blood plasminogen activator inhibitor-1 and intercellular adhesion molecule-1 as possible risk factors of atherosclerosis in Werner syndrome

Werner syndrome is a rare premature aging syndrome accompanied by severe atherosclerosis. The etiology of atherosclerosis is suspected to be due to its complications, namely diabetes mellitus, hyperinsulinemia and hyperlipidemia. But from an autopsy case we found that some other risk factors may be involved in the mechanism of atherosclerosis in this syndrome. Previously we revealed that the plasminogen activator inhibitor-1 (PAI-1) gene was being overexpressed in skin fibroblasts from a patient with this syndrome. PAI-1 is a potent inhibitor of tissue plasminogen activator and a possible risk factor of atherosclerosis. This led us to assess the plasma concentration of PAI-1. Our working hypothesis was that the PAI-1 gene was upregulated or not fully suppressed in cells responsible for the production of PAI-1 in plasma as well as in fibroblasts. The results show a high concentration of plasma PAI-1. One of the well-known physiological substances that induce the PAI-1 gene is tumor necrosis factor-alpha, which also induces other possible risk factors of atherosclerosis, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1. We found the serum concentrations of ICAM-1 to be elevated in patients with this syndrome. We conclude that high concentrations of PAI-1 and ICAM-1 in blood may be one of the potent causes of severe atherosclerosis in Werner syndrome.

[Antimicrobial activities of arbekacin against methicillin-resistant Staphylococcus aureus]

In order to evaluate antimicrobial activity of arbekacin (ABK), coagulase-type and minimum inhibitory concentrations (MICs) of ABK and other drugs were determined against 700 strains of methicillin-resistant Staphylococcus aureus (MRSA) that were obtained in our laboratory from 1990 to 1996, 7 years. The results are summarized as follows; 1. The MIC-distributions of ABK against 100 strains of MRSA obtained yearly did not show stochastically significant differences. 2. The coagulase-type distributions showed differences over the years. Coagulase-type II strains increased and type IV strains decreased, and MIC-distributions of ABK and other drugs were different according to coagulase-types. 3. The detection frequencies of ABK-resistant strains (MIC of ABK: > or = 12.5 micrograms/ml) were 2.0 approximately 8.0% through the years. The frequency reported in 1980 was equal to the frequency obtained in 1992 approximately 1993 in a nationwide survey. Coagulase-types II, IV and VII that were ABK-resistant strains were frequently obtained, and most of ABK-resistant strains were also highly resistant to gentamicin.

Differences in sarcoplasmic reticulum gene expression in myocardium from patients undergoing cardiac surgery. Quantification of steady-state levels of messenger RNA using the reverse transcription-polymerase chain reaction

Little is known about any alterations in sarcoplasmic reticulum (SR) gene expression associated with cardiac diseases of varying degrees of severity. We assessed, using the reverse transcription-polymerase chain reaction (RT-PCR) technique, SR Ca2+ transport protein gene expression in small tissue samples from failing hearts in patients undergoing cardiac surgery. Total RNA was extracted from 30- to 50-mg samples from the hearts of 13 patients with coronary artery disease, congenital heart disease, or valvular heart disease. We used RT-PCR to synthesize and amplify cDNA encoding cardiac SR Ca(2+)-ATPase, ryanodine receptor (RYR), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The amount of each mRNA in the sample was expressed relative to the amount of GAPDH mRNA. The expression level of each mRNA was correlated with the cardiac functional index. The mRNA levels for Ca(2+)-ATPase and RYR varied between heart samples, but showed a positive correlation with left ventricular ejection fraction. Ca(2+)-ATPase mRNA levels showed in inverse relationship with plasma brain natriuretic peptide. In addition, we isolated partial cDNA encoding a human cardiac RYR. The cDNA consisted of 487 nucleotides, and the nucleotide and deduced amino acid sequences showed 93% and 99% homology, respectively, to those of rabbit cardiac RYR. These results suggest that decreased levels of mRNA for SR Ca2+ transport protein could be related to abnormal cardiac function, regardless of the etiology of the heart disease. RT-PCR provides a rapid and economical way of quantifying the expression of multiple genes in small specimens and may, therefore, aid understanding of the pathophysiology and treatment of heart disease.

[Antimicrobial activities of cefetamet against clinical isolates from urinary tract infection]

In order to evaluate antimicrobial activity of cefetamet (CEMT), minimum inhibitory concentrations (MICs) of CEMT and control drugs were determined against Gram-negative rods mainly from complicated urinary tract infections examined in our laboratory from April to September of 1994. The results are summarized as follows; 1. The obtained strains were Citrobacter diversus 20, Citrobacter freundii 30, Enterobacter aerogenes 20, Enterobacter cloacae 30, Serratia marcescens 30, Proteus mirabilis 30, Proteus vulgaris 20 and Morganella morganii 30 strains, a total of 210 strains. 2. Excluding some resistant strains, the MIC-distribution showed showed that CEMT had strong antimicrobial activities against those strains from the MIC-distribution of this investigation. Compared to reports on CEMT in 1989, the MIC80 of CEMT in this investigation against clinical isolates were similar. The MIC50's of CEMT against E. aerogenes, S. marcescens, P. mirabilis, P. vulgaris and M. morganii in the previous examination were equal to or similar to the current results, but the MIC50's against C. freundii and E. cloacae were lower than the value of this report. The detection frequency of highly resistant strains of C. freundii and E. cloacae to cefteram and cefixime were similar to that of CEMT-resistant strains. Multiple drug resistant strains, among these bacterial species seemed to be increasing. 3. Compared to oral antibacterial agents of oxime cephems that were used in the past, CEMT showed higher peak values of urinary excretion concentration and higher blood levels were sustained for a longer period of time. CEMT-PI will be effective against urinary tract infections.

Cloning of a cDNA encoding the human transforming growth factor-beta type II receptor: heterogeneity of the mRNA

We have isolated two novel cDNAs encoding the transforming growth factor-beta (TGF-beta) type II receptor (TGF-beta IIR), termed TGF-beta IIR alpha and TGF-beta IIR beta 1 from a human fetal liver library. They have unique nucleotide (nt) sequences, compared with the reported TGF-beta IIR sequence, at the 5' end. Southern blot analysis using probes from each clone detected the specific genomic DNA fragments. RT-PCR analysis revealed a distinct pattern of expression for each isoform. These results indicated that TGF-beta IIR has heterogeneity in the structure, and the expression of TGF-beta IIR isoforms is differentially regulated. The heterogeneity of TGF-beta IIR molecules could be derived from alternative splicing and might elicit specific TGF-beta receptor functions.

Cloning and characterization of the gene encoding Halobacterium halobium adenylate kinase

The gene (AK) encoding adenylate kinase (AK) of Halobacterium halobium was cloned. AK consisted of 648 bp and coded for 216 amino acids (aa). S1 mapping and primer extension experiments indicated that the transcription start point (tsp) was located immediately upstream from the start codon. The TAT-like promoter sequence was found at a position 20-24 bp upstream from tsp. The most striking property of the enzyme was a putative Zn finger-like structure with four cysteines. It might contribute to the structural stability of the molecule in high-salt conditions. Phylogenetic analysis indicated two lineages of the AK family, the short and long types which diverged a long time ago, possibly before the separation of prokaryotes and eukaryotes. Although the H. halobium AK belongs to the long-type AK lineage, it is located in an intermediary position between the two lineages of the phylogenetic tree, indicating early divergence of the gene along the long-type lineage.

A genetic analysis system of Burkholderia cepacia: construction of mobilizable transposons and a cloning vector

A genetic analysis system of Burkholderia cepacia (Bc) was developed which included transposon mutagenesis and complementation of mutation with the cloned genes of interest. To deliver the transposon in this multidrug-resistant microorganism, two plasmids, pKN30 and pKN31, were constructed which contained Tn5 derivatives, Tn5-30Tp and Tn5-31Tp, respectively, carrying KmR and TpR genes. The plasmids have the origin of ColE1 replication and the mobilization gene of RP4. Tn5-31Tp was mobilized to Bc KF1, a strain isolated from a pneumonia patient, by the transfer system of RP4 integrated in the chromosome of Escherichia coli (Ec). Selection with trimethoprim resulted in generation of a number of transposants of Bc KF1. Fourteen protease-deficient mutants were isolated, all of which contained a single transposon marker in the chromosome. Thirteen protease-deficient mutants were also lipase deficient. An Ec-Bc shuttle plasmid, pTS1209, was constructed that consists of oriColE1, oripSa, ApR and CmR genes, and several unique restriction sites for cloning. Plasmid pTS1209 was successfully employed for cloning genes of Bc involved in protease production.

[Antimicrobial activity of cefodizime against clinical isolates]

In order to evaluate antimicrobial activity of cefodizime (CDZM), minimum inhibitory concentrations (MICs) of CDZM and control drugs were determined against clinical isolates collected from nation-wide medical institutions and in our laboratory from September to December of 1992 and from September to December of 1995. The results are summarized as follows: 1. Bacterial species with no or few strains resistant to CDZM included Streptococcus pyogenes, Haemophilus influenzae, Citrobacter koseri, Proteus mirabilis and Neisseria gonorrhoeae. The range of MIC values of CDZM against Klebsiella pneumoniae was spread. Other strains, Streptococcus pneumoniae, Moraxella subgenus Branhamella catarrhalis, Escherichia coli, Citrobacter freundii, Enterobacter spp., Serratia marcescens, Proteus vulgaris, Morganella morganii, Providencia spp., Peptostreptococcus spp. and Bacteroides fragilis group were resistant to cephems including CDZM. 2. The MIC90's of CDZM were 0.05 approximately 3.13 micrograms/ml against Streptococcus spp., H. influenzae, M. (B.) catarrhalis, E. coli, Klebsiella spp., P. mirabilis, N. gonorrhoeae and Peptostreptococcus spp. obtained in 1995 that were frequently found in daily treatment of infections. It appears that the effectiveness of CDZM was still relatively high against community-acquired infections. 3. Among H. influenzae isolates included imipenem (IPM)-resistant and norfloxacin (NFLX)-resistant strains. The MIC-range of CDZM against strains collected in 1995 including IPM-resistant and NFLX-resistant strains was < or = 0.025 approximately 0.1 microgram/ml, and MIC90 against these strains was 0.05 microgram/ml. CDZM showed strong antimicrobial activities against H. influenzae strains resistant to carbapenems and new-quinolones.

[Rhabdomyolysis related-acute renal failure in a patient with hyperosmolar nonketotic diabetic coma (HNKC): demonstration of myoglobin casts after normalization of renal function]

We report a patient with rhabdomyolysis secondary to hyperosmolar nonketotic diabetic coma (HNKC), who progressed to acute renal failure. A 43-year-old male with diabetes mellitus for three years was admitted to our hospital because of loss of consciousness. The laboratory findings at admission were as follows: serum glucose 1792 mg/dl, serum Na 129 mEq/1, BUN 71 mg/d1, serum creatinine 3.3 mg/d1, CPK 715 IU/1, plasma osmolality 370 mOsm/1, and negative urine ketone bodies. A diagnosis of HNKC was made. On the 2nd day, he had oliguria and the serum creatinine increased despite adequate treatment of HNKC by the administration of intravenous fluid and insulin. On the 4th day, CPK reached 47,300 IU/1, and serum myoglobin was also increased, indicating rhabdomyolysis. His renal function improved gradually and was almost normalized on the 20th day. Renal biopsy on the 23rd day showed myoglobin at the distal renal tubules, which appeared to be involved in the pathogenesis of renal failure by rhabdomyolysis. However, we found little abnormality association with diabetic nephropathy in the renal tissue. Since HNKC is known to induce acute renal failure rarely without diabetic nephropathy, these findings suggested that the acute renal failure was caused mainly by the rhabdomyolysis. Acute renal failure induced by rhabdomyolysis in patients with HNKC is rare, but fatal. The present study showed that the measurement of serum CPK and urine myoglobin was helpful for early diagnosis. Only 12 cases have been reported to have developed renal failure due to rhabdomyolysis among patients with HNKC. To our knowledge, we demonstrated for the first time that myoglobin at the distal renal tubules after renal function was normalized.

Ancient divergence of long and short isoforms of adenylate kinase: molecular evolution of the nucleoside monophosphate kinase family

Adenylate kinases (AK) from vertebrates are separated into three isoforms, AK1, AK2 and AK3, based on structure, subcellular localization and substrate specificity. AK1 is the short type with the amino acid sequence being 27 residues shorter than sequences of the long types, AK2 and AK3. A phylogenetic tree prepared for the AK isozymes and other members of the nucleoside monophosphate (NMP) kinase family shows that the divergence of long and short types occurred first and then differentiation in subcellular localization or substrate specificity took place. The first step involved a drastic change in the three-dimensional structure of the LID domain. The second step was caused mainly by smaller changes in amino acid sequences.

A ColE1-encoded gene directs entry exclusion of the plasmid

To detect entry exclusion of the ColE1 plasmid, we established an assay system that was not influenced by incompatibility of extant plasmids in the recipient cells or by the viability of the cells due to the killing action of colicin E1 protein. The assay revealed that exc1 and exc2, assigned as genes directing entry exclusion, had no exclusion activity. Instead, mbeD, which had been characterized as a gene for plasmid mobilization, directed the exclusion activity. MbeD was overexpressed and identified as a 35S-labeled protein, which was recovered in both the soluble and membrane fractions, particularly in the inner membrane fraction. An amphipathic helical structure was predicted in the N-terminal region of MbeD as well as in the corresponding homologous proteins of ColA and ColK. These proteins may bind to the inner membrane via the N-terminal amphipathic helix and function in entry exclusion.

Cloning, DNA sequencing, and amino acid sequencing of catechol 1,2-dioxygenases (pyrocatechase) from Pseudomonas putida mt-2 and Pseudomonas arvilla C-1

Catechol 1,2-dioxygenase catalyzes the oxygenative ring cleavage of catechol to form cis,cis-muconic acid and is encoded by a catA gene. We have cloned a catA gene from Pseudomonas putida mt-2 using a PCR product of amino acid sequence-based primers as a probe. The amino acid sequence deduced from the 930 nucleotides was in complete agreement with the chemically determined sequence of the protein. Crude extracts of Escherichia coli cells carrying the catA gene downstream from the lac promoter showed the enzyme activity. By using the same probe, we also cloned and sequenced the catA beta gene for catechol 1,2-dioxygenase isozyme beta beta from Pseudomonas arvilla C-1, which has three isozymes, alpha alpha, alpha beta, and beta beta (C. Nakai, H. Horiike, S. Kuramitsu, H. Kagamiyama, and M. Nozaki, 1990, J. Biol. Chem. 265, 660-665). There was very high homology between isozyme beta beta of the C-1 strain and the enzyme of the mt-2 strain in both the amino acid (98%) and the DNA sequences (97%). A preference for the use of codons terminating in C and G was found in the coding region of both the enzymes, which contributed to the high G + C content (65-66%) of the genes. A comparison of the DNA sequences of various catA genes from other sources revealed their common ancestry, whereas a comparison of the amino acid sequences of the enzymes revealed clear reflection of substrate specificity. Tyrosyl and histidyl residues for proposed ligands of ferric ion are conserved in all catechol 1,2-dioxygenases.