Familial lichen nitidus

I report familial lichen nitidus in a 33-year-old father and his 3-year-old daughter. Histopathology of small papules in both cases revealed typical features of lichen nitidus. Immunohistochemical examination showed UCHL1-positive, L-26-negative lymphocytes and HAM56-positive histiocytes and multinucleated giant cells in the dermal infiltrate in both cases.

A novel integron-like element carrying the metallo-beta-lactamase gene blaIMP

A plasmid-mediated metallo-beta-lactamase gene was cloned from a carbapenem-resistant Serratia marcescens strain, AK9373. The metallo-beta-lactamase gene was identical to the blaIMP, and it was located in the space between an integrase-like gene and an aac(6')-Ib-like gene. The deduced amino acid sequence for the putative integrase gene showed considerable identity (60.9%) to that of the Escherichia coli integrase reported. Sequences similar to the GTTRRRY and an atypical 59-base element containing a 67-bp inverted repeat sequence, which were peculiar to the integrase-dependent recombination, were also conserved in the flanking regions of the blaIMP gene. These findings imply that the metallo-beta-lactamase gene in S. marcescens AK9373 is carried by a novel integron-like element that is mediated by a transferable large plasmid.

Synthesis and secretion of tobacco neutral PR-5 protein by transgenic tobacco and yeast

Tobacco neutral osmotin-like protein was expressed in both homologous and heterologous expression systems. Osmotin-like protein was retained in tobacco cells when expressed as the prepro-form, whereas deletion of the carboxyl-terminal propeptide of 22 amino acids induced its secretion into the extracellular fluid. Without the amino-terminal signal peptide, there was no accumulation of osmotin-like protein. When the construct with both the amino- and carboxyl-terminal peptides was introduced to methylotrophic yeast, divergent osmotin-like protein forms were found in the cell and medium. Results suggest that the amino-terminal signal of the osmotin-like protein is essential for the transport of protein to the endoplasmic reticulum both in tobacco and yeasts but that the carboxyl-terminal propeptide signal is effective only for intracellular retention in tobacco.

Antibiotic susceptibility profiles of Bacteroides fragilis and Bacteroides thetaiotaomicron in Japan from 1990 to 1992

The antimicrobial susceptibility of clinical isolates of Bacteroides fragilis and Bacteroides thetaiotaomicron collected from December 1990 through November 1992 was determined by the agar dilution technique. Metronidazole, imipenem, and cefoperazone/sulbactam remained highly active against both organisms. Rates of resistance to those agents were 0, 2%, and 0.9% in B. fragilis and 0, 0.9%, and 3% in B. thetaiotaomicron, respectively. Cefoxitin and other cephamycins were active against B. fragilis; rates of resistance to these agents did not tend to increase. With the inclusion of these data, the variation of rates of resistance to several agents was summarized for each year from 1987 to 1992. Rates of resistance to imipenem decreased in 1991 and 1992 among isolates of B. fragilis (2.3% in 1991, 1.8% in 1992) and B. thetaiotaomicron (2.4% in 1991, 0 in 1992). Rates of resistance to cefoxitin in B. thetaiotaomicron varied from 10% to 38% during these 6 years, though the distributional peak of MIC values did not change. The rate of resistance to ofloxacin in B. fragilis increased from 42% in 1989 to 81% in 1992. The rate of resistance to ampicillin in B. thetaiotaomicron was 68% in 1992--approximately 30% lower than before. Mostly, however, the rates of resistance to the antimicrobial agents examined did not change significantly.

Altered brain contents of neuropeptides in spontaneously epileptic rats (SER) and tremor rats with absence seizures

Immunoreactive- (IR-) somatostatin (SRIF), neuropeptide Y (NPY) and corticotropin-releasing factor (CRF) contents were investigated in the brain of tremor rats with absence-like seizure and spontaneously epileptic rats (SER), which is a genetically defined double-mutant (zi/zi, tm/tm) obtained by mating zitter homozygote (zi/zi) with tremor heterozygote (tm/+) and shows both absence-like seizure and tonic convulsions. Increased levels of IR-NPY and IR-CRF were observed in several regions including the amygdala and hippocampus in homozygous SER compared to heterozygous SER (zi/zi, tm/+ or +/+). Homozygous tremor rats (tm/tm) showed lower levels of IR-NPY and IR-CRF contents mainly in the hippocampus and mesolimbic system (entorhinal and pyriform cortex and nucleus accumbens) than heterozygous tremor rats. IR-SRIF contents of homozygous SER were higher in frontal cortex than heterozygous SER and in amygdala than homozygous tremor rats. No change of IR-SRIF between groups was noted in the hippocampus among brain structures underlying epileptogenicity. The results suggest that the change of neuropeptide levels, most conspicuous in NPY among three peptides tested, may be involved in the phenotypical manifestation of seizures in SER and tremor rats, and that the development of tonic convulsion and absence seizures may be differently associated with the change of brain neuropeptide levels.

Bacteriology of chronic otitis media, chronic sinusitis, and paranasal mucopyocele in Japan

A bacteriologic study of cases of chronic otitis media, chronic sinusitis, and paranasal mucopyocele diagnosed at Gifu University Hospital was performed between 1989 and 1992. Bacteria were isolated from all of 13 samples of discharge from the ears of patients with chronic otitis media, all of 14 mucosal biopsy specimens from patients with chronic sinusitis, 8 of 10 aspirate samples from patients with chronic sinusitis, and 9 of 15 aspirates samples from patients with mucopyocele. Cultures often yielded polymicrobial growth, with an average of 3.1, 3.8, and 4.2 species per positive specimen from chronic otitis media, chronic sinusitis, and mucopyocele, respectively. The most commonly encountered anaerobes were Peptostreptococcus, Propionibacterium, and Prevotella species; the most common aerobes were Staphylococcus and Streptococcus species. One strain of Prevotella melaninogenica highly resistant to ampicillin and two strains of Peptostreptococcus resistant to cefaclor were found.

Cytokine stimulation during Salmonella typhimurium sepsis in Itys mice

Cytokine production was measured in mice during Salmonella typhimurium sepsis and intoxication. In mice given live S. typhimurium (10 cfu/mouse), by intra-peritoneal injection, serum levels of tumour necrosis factor (TNF)-alpha and interleukin-6 increased steadily from day 1 until day 4. Interferon-gamma levels showed a transient peak on day 3. Interleukin-1-alpha levels were very low. There were high bacterial counts in the livers at day 3 and deaths occurred from day 4 onwards. Intraperitoneal injection of lipopolysaccharide or heat-killed bacteria also induced all of the cytokines, but their time of appearance and levels varied greatly. Cytokine induction by heat-killed bacteria was more marked. Endotoxaemia decreased with time during intoxication and increased during sepsis. Bioactive TNF, as measured by a cytotoxicity assay, was found only in mice given heat-killed bacteria.

Properties of poly(3-hydroxybutyrate) depolymerase from a marine bacterium, Alcaligenes faecalis AE122

Alcaligenes faecalis AE122 that used poly(3-hydroxybutyrate) (PHB) as a sole source of carbon was newly isolated from a coastal seawater sample. The strain required seawater for growth on PHB as well as in a nutrient broth, in which seawater could be replaced by an appropriate concentration of NaCl. PHB depolymerase was purified to homogeneity from the culture supernatant of A. faecalis AE122 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme consisted of a monomer subunit with a molecular mass of 95.5 kDa. The N-terminal amino acid sequence was GAWQNNLAGGFNKV. The dimeric and trimeric esters of 3-hydroxybutyrate were the main hydrolysis products of the purified enzyme. The enzyme was most active at pH 9.0 and 55 degrees C and was inhibited by phenylmethylsulfonyl fluoride. Several cations in seawater greatly enhanced the enzyme activity.

[Changes in serum calcium concentration following eel calcitonin analogue administration as an index of osteoclastic bone resorption in patients with secondary hyperparathyroidism]

It has been suggested that the intensity of hypocalcemic response to administration of calcitonin may reflect the magnitude of osteoclastic activity. To determine whether this hypothesis is correct or not, I performed a calcitonin-loading test in twenty dialysis patients with secondary hyperparathyroidism. The test involved the intravenous injection of 120 MRC units of synthetic eel calcitonin analogue for 3 hours. Serum calcium concentration fell from 9.6 +/- 0.9 mg/dl to 8.7 +/- 0.9 mg/dl following calcitonin administration (p < 0.001). There was a statistically significant correlation between the fall in serum calcium concentration and the baseline intact parathyroid hormone levels (r = 0.661, p < 0.002), as well as the fall in serum calcium concentration and baseline serum alkaline phosphatase activity (r = 0.817, p < 0.001), respectively. From these findings, it was concluded that calcitonin lowers serum calcium concentration in proportional to the activity of osteoclastic bone resorption. To determine whether the effect of calcitonin on calcium concentration related to PTH secretion, same test was performed before and after parathyroidectomy (PTX) in 9 patients with severe secondary hyperparathyroidism required surgery. The fall in serum calcium concentration during calcitonin administration before PTX was significantly greater than that of after PTX (p < 0.05). Thus, it is concluded that calcitonin-loading test is clinically usefull index to estimate osteoclastic activity in patients with secondary hyperparathyroidism.

Supplemental dietary cystine elevates kidney metallothionein in rats by a mechanism involving altered zinc metabolism

Dietary sulfur-containing amino acids influence zinc and copper status. This study was conducted to investigate the relationship between the status of these elements and tissue metallothionein in rats fed diets supplemented with sulfur-containing amino acids. In a series of experiments, a diet containing 100 g casein/kg diet was unsupplemented or supplemented with L-cystine (3-50 g/kg diet) or L-methionine (3 or 30 g/kg diet). Kidney concentrations of zinc and copper in rats fed the diet supplemented with high levels of cystine (25 or 50 g/kg) were significantly higher than those in rats fed the unsupplemented diet. Kidney concentrations of metallothionein and metallothionein mRNA were also significantly higher in rats fed cystine-supplemented diets. There was a correlation (r = 0.838, P < 0.01) between the levels of zinc and metallothionein in kidney of rats fed the diets with different levels of cystine and zinc. However, in the rats fed the diets with different levels of cystine and copper, the correlation was not as strong (r = 0.587, P < 0.01). The changes in kidney metallothionein concentration due to the addition of 3 or 30 g/kg cystine were associated with parallel changes in serum zinc concentration and in apparent absorption of zinc, but not in serum copper concentration or apparent absorption of copper. Addition of 3 or 30 g methionine/kg diet to the diet did not affect kidney concentrations of metallothionein or zinc. These results indicate that supplementation of cystine to the diet can induce kidney metallothionein through a mechanism involving altered zinc metabolism.

A novel formaldehyde oxidation pathway in methylotrophic yeasts: methylformate as a possible intermediate

A considerable amount of methylformate accumulated in the culture medium of methanol-grown methylotrophic yeasts. Methylformate is considered as an intermediate in a novel formaldehyde oxidation pathway. Through investigations with Pichia methanolica, methylformate formation was found to be catalysed by a new type of alcohol dehydrogenase, which was named methylformate synthase. When cells were grown on a relatively high concentration of methanol or exposed to a high concentration of formaldehyde, formation of methylformate was enhanced and the level of methylformate synthase in the cells increased. How methylformate synthase is involved in formaldehyde oxidation and formaldehyde detoxification is discussed.

Plasmid-mediated dissemination of the metallo-beta-lactamase gene blaIMP among clinically isolated strains of Serratia marcescens

The distribution of strains producing metallo-beta-lactamase among 105 strains of Serratia marcescens was investigated. All of these strains were isolated in seven general hospitals located in Aichi Prefecture, Japan, from April to May 1993. Southern hybridization analysis suggested that four S. marcescens strains, AK9373, AK9374, AK9385, and AK9391, had a metallo-beta-lactamase genes similar to the blaIMP gene found by our laboratory (E. Osano, Y. Arakawa, R. Wacharotayankun, M. Ohta, T. Horii, H. Ito, F. Yoshimura, and N. Kato, Antimicrob. Agents Chemother. 38:71-78, 1994), and these four strains showed resistance to carbapenems as well as to the other broad-spectrum beta-lactams. In particular, strains AK9373, AK9374, and AK9391 showed an extraordinarily high-level resistance to imipenem (MICs, > or = 64 micrograms/ml), whereas strain AK9385 demonstrated moderate imipenem resistance (MIC, 8 micrograms/ml). The imipenem resistance of AK9373 was transferred to Escherichia coli CSH2 by conjugation with a frequency of 10(-5). The DNA probe of the blaIMP gene hybridized to a large plasmid (approximately 120 kb) transferred into the E. coli transconjugant as well as to the large plasmids harbored by AK9373. On the other hand, although we failed in the conjugational transfer of imipenem resistance from strains AK9374, AK9385, and AK9391 to E. coli CSH2, imipenem resistance was transferred from these strains to E. coli HB101 by transformation. A plasmid (approximately 25 kb) was observed in each transformant which acquired imipenem resistance. The amino acid sequence at the N terminus of the enzyme purified from strain AK9373 was identical to that of the metallo-beta-lactamase IMP-1. In contrast, strains ES9348, AK9386, and AK93101, which were moderately resistant to imipenem (MICs, > or = 4 to < or = 8 micrograms/ml), had no detectable blaIMP gene. As a conclusion, 19% of clinically isolated S. marcescens strains in Aichi Prefecture, Japan, in 1993 were resistant to imipenem (MICs, > or = 2 micrograms/ml), and strains which showed high-level imipenem resistance because of acquisition of a plasmid-mediated blaIMP-like metallo-beta-lactamase gene had already proliferated as nosocomial infections, at least in a general hospital.

Genomic organization of the Klebsiella pneumoniae cps region responsible for serotype K2 capsular polysaccharide synthesis in the virulent strain Chedid

The genomic organization of the chromosomal cps region that is responsible for capsular polysaccharide synthesis in Klebsiella pneumoniae Chedid (O1:K2) was investigated. Deletion analyses and Southern hybridization studies suggested that the central region of the cloned 29-kb BamHI fragment is indispensable for K2 capsular polysaccharide synthesis. The 24,329-bp nucleotide sequence of the Klebsiella cps region was determined and deposited in the EMBL and GenBank databases through DDBJ and assigned accession number D21242. Nineteen possible open reading frames (ORFs) were identified in the sequenced area. Among them, 13 ORFs are very close to each other. Six of the 19 ORFs show considerable nucleotide sequence similarities to Salmonella typhimurium cpsG, cpsB, rfbP, and orf2.8, Escherichia coli gnd, and Haemophilus influenzae bexD, respectively. Moreover, the deduced amino acid sequence of the ORF10 product demonstrated a highly hydrophobic profile and showed putative membrane topology similarity to Rickettsia prowazekii ATP/ADP translocase. Nucleotide sequence similar to the sigma 54-dependent promoter, as well as the usual -35 and -10 sequences, were identified just upstream of ORF3, which is the first ORF in the polycistronic structure. Furthermore, a sequence (GGGCGGTAGCGT) found just downstream of the sigma 54-dependent promoter-like sequence was generally conserved among gene clusters implicated in cell surface polysaccharide synthesis, such as Salmonella rfb and viaB and E. coli kpsMT and rfaQPG. A possible transcriptional terminator with a hairpin loop structure found just downstream of ORF15 that is a homolog of E. coli gnd. K2 capsular polsaccharide biosynthesis in E. coli K-12 depends on cpsB (mannose-1-phosphate guanyltransferase gene), and Klebsiella cpsB, found in the downstream region of the polycistronic structure, was able to complement cpsB of E. coli. Results of transposon insertion and promoter-cloning analyses were consistent with the results of nucleotide sequence analysis.

Expression of the O9 polysaccharide of Escherichia coli: sequencing of the E. coli O9 rfb gene cluster, characterization of mannosyl transferases, and evidence for an ATP-binding cassette transport system

The rfb gene cluster of Escherichia coli O9 directs the synthesis of the O9-specific polysaccharide which has the structure -->2-alpha-Man-(1-->2)-alpha-Man-(1-->2)-alpha-Man-(1-->3)-alpha- Man-(1-->. The E. coli O9 rfb cluster has been sequenced, and six genes, in addition to the previously described rfbK and rfbM, were identified. They correspond to six open reading frames (ORFs) encoding polypeptides of 261, 431, 708, 815, 381, and 274 amino acids. They are all transcribed in the counter direction to those of the his operon. No gene was found between rfb and his. A higher G+C content indicated that E. coli O9 rfb evolved independently of the rfb clusters from other E. coli strains and from Shigella and Salmonella spp. Deletion mutagenesis, in combination with analysis of the in vitro synthesis of the O9 mannan in membranes isolated from the mutants, showed that three genes (termed mtfA, -B, and -C, encoding polypeptides of 815, 381, and 274 amino acids, respectively) directed alpha-mannosyl transferases. MtfC (from ORF274), the first mannosyl transferase, transfers a mannose to the endogenous acceptor. It critically depended on a functional rfe gene (which directs the synthesis of the endogenous acceptor) and initiates the growth of the polysaccharide chain. MtfB (from ORF381) then transfers two mannoses into the 3 position of the previous mannose, and MtfA (from ORF815) transfers three mannoses into the 2 position. Further chain growth needs only the two transferases MtfA and MtfB. Thus, there are fewer transferases needed than the number of sugars in the repeating unit. Analysis of the predicted amino acid sequence of the ORF261 and ORF431 proteins indicated that they function as components of an ATP-binding cassette transport system. A possible correlation between the mechanism of polymerization and mode of membrane translocation of the products is discussed.

Usefulness of granulocyte colony-stimulating factor on neutropenia in patients of invasive mole and choriocarcinoma

The effect of human granulocyte colony stimulating factor (hG-CSF) was investigated on the proliferation of choriocarcinoma cells in vitro. No growth-stimulating effect was observed. Then, 22 patients with invasive mole and 9 patients with choriocarcinoma who received combination chemotherapy were treated with hG-CSF when white blood cell counts decreased below 2,000/mm3. The duration of neutropenia was reduced significantly by 3-4 days with the use of hG-CSF. No side effects were observed. These results indicate safety and usefulness of hG-CSF as an adjunct to chemotherapy in the treatment of gestational trophoblastic disease.

Expression of Saccharomyces adenylate kinase gene in Candida boidinii under the regulation of its alcohol oxidase promoter

The methylotrophic yeast, Candida boidinii, was investigated as a new efficient host for heterologous gene expression. The Saccharomyces cerevisiae adenylate kinase gene (ADK1) was used as the first example for heterologous enzyme production in C. boidinii. C. boidinii cells were transformed with plasmids harboring the S. cerevisiae ADK1 gene under the alcohol oxidase (C. boidinii AOD1) promoter. The chromosome-integrant strains produced adenylate kinase protein corresponding to 22%-28% of the total soluble proteins in an enzymatically active form. When the three-copy integrative transformant was grown for 60 h on methanol-glycerol medium in a 1.5-l jar fermentor, adenylate kinase was produced intracellularly with a yield of up to 2 milligrams culture medium. As the expression of the S. cerevisiae ADK1 in C. boidinii was under similar regulation to that of the C. boidinii AOD1, the previously cloned 1.7-kb AOD1 promoter fragment was proved to harbor sufficient cis elements for AOD1 regulation and found to be an efficient promoter for heterologous gene expression.

Purification and properties of fructosyl lysine oxidase from Fusarium oxysporum S-1F4

Fructosyl lysine oxidase (FLOD) was examined for its use in the enzymatic measurement of the level of glycated albumin in blood serum. To isolate microorganisms having such an enzyme activity, we used N epsilon-fructosyl N alpha-Z-lysine (epsilon-FL) as a sole nitrogen source in the enrichment culture medium. The isolated fungus, strain S-1F4, showed a high FLOD activity in the cell-free extract and was identified as Fusarium oxysporum. FLOD was purified to an apparent homogeneity on SDS-PAGE. The molecular mass of the subunit was 50 kDa on SDS-PAGE and seemed to exist in a monomeric form. The enzyme had an absorption spectrum characteristic of a flavoprotein and the flavin was found to be covalently bound to the enzyme. The enzyme acted against N epsilon-fructosyl N alpha-Z-lysine and N alpha-fructosyl N epsilon-Z-lysine and showed specificity for fructosyl lysine residues.

[Relative hypoparathyroidism associated with CAPD treatment using normo-calcemic (3.5mEq/1) dialysate: an approach from transperitoneal calcium balance]

We investigated factors affecting net transperitoneal calcium balance (Ca-BL) and the level of parathyroid hormone in relation to stepwise changes in serum calcium, by short PET (peritoneal equibrium test during 240 min: using 2000 ml of 2.5% dextrose dialysate containing 1.75 mmol/L Ca) in uremic patients undergoing stable CAPD. We calculated Ca-BL (mg/effluent/PET) of 244 effluents obtained from 90 patients receiving calcium carbonate as a phosphate binder without vitamin D supplementation. Their serum calcium level corrected with albumin (cSCa), alkaline phosphatase activity (ALP) and intact-PTH level was 9.7 +/- 0.9 mg/dl, 236 +/- 83 mIU/ml and 153.0 +/- 172.4 pg/ml, respectively. We proposed two statistic significant regression lines between Ca-BL and total drainage effluent volume (Ca-BL = 133X - 0.056: r = 0.981, P < 0.001), cSCa (Ca-BL = -12.9X + 123.6: r = 0.941, P < 0.01). Total drainage volume (TDV) and cSCa were two major factors affecting Ca-BL. A TDV level of 2430 ml/240 min-PET or more was required for positive Ca-BL in cases with 9.5-10.0 mg/dl of cSCa, using this linear regression analysis. A cSCa level of 9.6 mg/dl or more was also required for positive Ca-BL in cases with 2400-2600 ml/240min-PET. We also proposed a significant linear regression line between the intact-PTH level and cSCa (i-PTH = -90.5X + 1015.8, r = 0.973, P < 0.01). This line suggest that 200 pg/ml of intact PTH was obtained by 9.0 mg/dl or less of cSCa level in 90 CAPD uremic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Sensitive assay for detection of hepatocellular carcinoma associated gene transcription (alpha-fetoprotein mRNA) in blood

The sensitivity of RT-PCR and nested RT-PCR for detection of circulating hepatocellular carcinoma was assessed by demonstrating the tumor cell-associated gene transcription, alpha-fetoprotein mRNA, in the nuclear cells of peripheral blood. When HepG2 cells were mixed in blood, 100-1000 tumor cells/5ml of blood could be detected by RT-PCR, in contrast to 1-10 tumor cells/5ml of blood by nested RT-PCR. In addition, 2 x 10(4) copies of AFP mRNA were found in one HepG2 cell when analyzed by the quantitative nested RT-PCR assay. Thus, the nested RT-PCR assay could provide a useful tool for detecting a tiny amount of circulating tumor cells in patients with hepatocellular carcinoma presenting extra-hepatic metastasis.

Suppression of gelatinase production with decreased invasiveness of choriocarcinoma cells by human recombinant interferon beta

OBJECTIVE

Choriocarcinoma is a highly invasive gynecologic tumor, and hematogenous metastases frequently develop. To establish a molecular basis for antiinvasion therapy of choriocarcinoma, we examined the effects of human recombinant interferons on gelatinase production and invasion by choriocarcinoma cells.

STUDY DESIGN

Using five choriocarcinoma cell lines, we measured gelatinase activity by gelatin zymography. The effects of recombinant interferons (rIFN-alpha, rIFN-beta, and rIFN-gamma) were then analyzed by Western blot analysis and chemoinvasion assay.

RESULTS

High levels of 72 kd gelatinase activity were detected in the highly invasive choriocarcinoma cell lines, two of which also contained an active form of 72 kd gelatinase with an apparent molecular mass of 68 kd. Gelatinase production was decreased by incubation with rIFN-beta. In the chemoinvasion assay, only rIFN-beta had an inhibitory effect on the invasiveness of tumor cells without a cytotoxic effect.

CONCLUSION

Choriocarcinoma cells showed high 72 kd gelatinase activity, which suggested a role for the enzyme in vascular metastasis. Studies on the use of rIFN-beta to inhibit metastasis of choriocarcinoma via suppression of gelatinase production are warranted.

Cloning, sequence analysis, and expression of the gene encoding formaldehyde dismutase from Pseudomonas putida F61

The gene (fdm) coding for formaldehyde dismutase (EC 1.2.99.4) from a genomic library of formaldehyde-tolerant Pseudomonas putida F61 was cloned and expressed in Escherichia coli. The nucleotides of the cloned DNA were sequenced; they included a single open reading frame of 1200 base pairs, coding for a putative protein with a molecular weight of 42,848. Sequencing of the first 20 N-terminal amino acid residues and of an internal part of the enzyme purified from P. putida F61 established the identity and the start codon of fdm. Comparison of the amino acid sequence predicted from fdm with that of alcohol dehydrogenase from horse liver suggested a putative pyridine-dinucleotide-binding domain in fdm, and also potential ligands for the catalytic domain and the second zinc atom-folding domain. fdm seemed to be expressed in E. coli under control of the promoter of fdm; there was an E. coli promoter-like sequence upstream from the gene. The enzyme expressed in E. coli was purified to homogeneity. The molecular weight and the sequence of the first 20 N-terminal amino acid residues were identical with those of P. putida formaldehyde dismutase. Each subunit contained 1 mol of NAD(H) and 2 mol of zinc per mol of protein. The enzyme produced in E. coli catalyzed the dismutation of formaldehyde to form methanol and formic acid at the ratio of 1:1 in the absence of the exogenous electron acceptor, NAD(H).

Susceptibility of human T-lymphotropic virus type I infected cell line MT-2 to hepatitis C virus infection

To obtain a hepatitis C virus (HCV) proliferation system, we examined the susceptibility of various cultured cell lines to HCV infection. We found that a human T-lymphotropic virus type I infected cell line MT-2 was fairly sensitive to HCV infection. Using the polymerase chain reaction, intracellular positive-stranded HCV RNA was detected until at least 15 days postinoculation (p.i.). Intracellular negative-stranded HCV RNA was also detected at 10 days p.i., although not at 7 days p.i., suggesting that HCV is replicating in MT-2 cells 10 days p.i. Sequence analysis of hypervariable region 1 (HVR1) revealed that HVR1 sequences from cells 10 days p.i. had become homogeneous, although HVR1 sequences from the inoculum showed the typical quasi-species. We also found a lack of anti-HVR1 antibody against the HVR1 species which became homogeneous at 10 days p.i., although we easily detected antibody against the other HVR1 species obtained from the inoculum. These findings suggest that MT-2 cells are susceptible to HCV infection and are capable of supporting HCV replication.