Characteristics of a Streptomyces coelicolor A3(2) extracellular protein targeting chitin and chitosan

Upstream of the Streptomyces coelicolor A3(2) chitinase G gene, a small gene (named chb3) is located whose deduced product shares 37% identical amino acids with the previously described CHB1 protein from Streptomyces olivaceoviridis. The chb3 gene and its upstream region were cloned in a multicopy vector and transformed into the plasmid-free Streptomyces lividans TK21 strain. The CHB3 protein (14.9 kDa) was secreted by the S. lividans TK21 transformant during growth in the presence of glucose, N-acetylglucosamine, yeast extract, and chitin. The protein was purified to homogeneity using anionic exchange, hydrophobic interaction chromatographies, and gel filtration. In contrast to CHB1, CHB3 targets alpha-chitin, beta-chitin, and chitosan at pH 6.0 but does so relatively loosely. The ecological implications of the divergence of substrate specificity of various types of chitin-binding proteins are described.

Symmetrical cationic triglycerides: an efficient synthesis and application to gene transfer

Some cationic triglycerides 1Aa-1Cb which have a symmetrical structure were effectively synthesized and formulated into cationic liposomes with the co-lipid dioleoylphosphatidylethanolamine (DOPE) and/or dilauroylphosphatidylcholine (DLPC). The plasmid encoding a luciferase was delivered into CHO cells by using these cationic liposomes. Our symmetrical cationic triglycerides showed high transfection activity when DOPE was used as a co-lipid. Among the symmetrical cationic triglycerides synthesized here, 1Ab and 1Ac, which have an oleoyl group at the 1- and 3-position in the glycerol backbone and also have a relatively long linker connecting the 2-hydroxy group in glycerol with the quaternary ammonium head group, were found to be the most suitable for gene delivery into cells. The transfection activity of the symmetrical cationic triglyceride 1Ab was comparable with that of its asymmetrical congener 6 and several times higher than that of Lipofectin.

Epoprostenol sodium, a prostaglandin I2, lacks tumor promoting effects in a medium-term liver carcinogenesis bioassay in rats

Potential modifying effects of epoprostenol sodium administration on liver carcinogenesis were investigated in male F344/DuCrj rats initially treated with N-nitrosodiethylamine (DEN). Two weeks after a single dose of DEN (200 mg/kg, intraperitoneally), rats daily received subcutaneously epoprostenol sodium at doses of 0, 1, 10 and 100 microg/kg, or were fed phenobarbital sodium (PB) at a dietary level of 500 parts per million (ppm) as positive control for 6 weeks. All animals were subjected to partial hepatectomy at week 3, and were killed at week 8. Prominent flushing of extremis and signs of behavioural depression occurred after injection and lasted for 1 h in rats given 100 microg/kg epoprostenol sodium. Such clinical signs were slight in rats treated with 10 microg/kg, but not observed with 1 microg/kg. Marked decrease in body weight gain was noted in rats given 100 microg/kg. Statistically significant changes in relative liver weights were not found in any group given the test chemical. Epoprostenol sodium did not significantly increase the quantitative values for glutathione S-transferase placental form (GST-P) positive liver cell foci observed after DEN initiation, in clear contrast to the positive control. The results thus demonstrate that epoprostenol sodium lacks modifying potential for liver carcinogenesis in our medium-term bioassay system.

Expression of 2-halobenzoate dioxygenase genes (cbdSABC) involved in the degradation of benzoate and 2-halobenzoate in Burkholderia sp. TH2

Burkholderia sp. TH2, isolated from soil, utilizes 2-chlorobenzoate (2CB) and benzoate (BA) as its sole source of carbon and energy. The genes for 2-halobenzoate dioxygenase (cbdABC) from Burkholderia sp. TH2 were cloned and sequenced. The predicted amino acid sequences of all the gene products are highly similar to the cbd gene products of Pseudomonas sp. 2CBS. Disruption of the promoter region of cbdA resulted in loss of growth on 2CB and BA, indicating that these genes are involved in the growth of TH2 on these substrates. Expression of the cbd genes was analyzed by transcriptional fusion assay. The cbdS gene, a possible araC/xylS-type transcriptional regulatory gene, was shown to positively regulate the expression of cbdA. In addition, the effectors of CbdS were shown to be 2CB, 2-bromobenzoate, o-toluate (2-methylbenzoate), 2-iodobenzoate, and BA. Primer extension analysis showed that the cbdA mRNA started at two positions, 14 and 15 nucleotides upstream from the cbdA start codon, ATG. A pair of direct repeats, identical to that of the Pm promoter of the TOL plasmid, was found upstream of -35 hexamer of the cbdA promoter.

Cryogelation in vitro

Cryogel is a physical gel formed by the heterophilic aggregation of extra domain A containing fibronectin (EDA(+)FN), plasma fibronectin (pFN), fibrinogen (Fbg) and heparin (Hep). Cryogelation is controlled by the interactions between each aggregate and the amount of aggregates. Therefore, the present study attempted to elucidate these properties by studying turbidity (tau). Although only Fbg formed a self-aggregate under low temperatures, from the temperature dependence of tau, the amount of aggregate in three-element (pFN/Fbg/Hep) solution surpassed that of the EDA(+)FN/Fbg/Hep system. The optimal condition for cryogelation was afforded by a solution with Fbg/EDA(+)FN/pFN/Hep expressed in the molar ratio of 12:0.04:0.79:1. This cryogel structure in solution was probably formed via structural changes induced by pFN in Fbg. The structural change in Fbg was examined by circular dichroism under optimal conditions. This concept was based on observations of the direct transmission scanning electron microscopy of a cryogel. The EDA(+)FN/pFN/Fbg/Hep aggregates displayed a network structure that manifested particulate crosslinkage. Cryogelation, a phenomenon related to induction of rheumatoid arthritis in humans, was facilitated by both the EDA(+)FN-Hep interaction and the structural changes of Fbg induced by pFN.

Acyclic carotenoids and their oxidation mixtures inhibit the growth of HL-60 human promyelocytic leukemia cells

Lycopene has been known as a potential food component for cancer prevention, since tomato consumption was shown to be associated with reduced risk of certain cancers. We used HL-60 cells as a model of cancer cells to investigate whether acyclic carotenoids, such as phytoene, phytofluene, and zeta-carotene present in tomatoes, other than lycopene, as well as oxidation mixtures of these carotenoids, are potentially involved in the cancer-preventive action of tomatoes. When HL-60 cells were grown in the carotenoid-supplemented medium for 120 hours, zeta-carotene and phytofluene at 10 microM inhibited cell growth to 3.7% and 22.6% of the growth in control culture, respectively, although they were extremely unstable in the culture medium. The oxidation mixture of each carotenoid, which was prepared by incubation in toluene at 37 degrees C for 24 hours, more strongly inhibited cell growth than each intact carotenoid. The growth inhibition by lycopene was remarkably enhanced by its oxidation before supplementation to the medium. Phytofluene, zeta-carotene, and the oxidation mixture of lycopene induced apoptosis in HL-60 cells during incubation for 24 hours. The addition of alpha-tocopherol to the medium did not eliminate growth inhibition by the oxidation mixture of lycopene. These results suggest that the acyclic carotenoids inhibit cell growth through apoptosis induction and that oxidation products of the carotenoids participate in the growth inhibition.

The chlorobenzoate dioxygenase genes of Burkholderia sp. strain NK8 involved in the catabolism of chlorobenzoates

Burkholderia sp. NK8 grows abundantly on 3-chlorobenzoate (3CB),4-chlorobenzoate (4CB) and benzoate. The genes encoding the oxidation of (chloro)benzoates (cbeABCD) and catechol (catA, catBC), the LysR-type regulatory gene cbeR and the gene cbeE with unknown function, all of which form a single cluster in NK8, were cloned and analysed. The protein sequence of chlorobenzoate 1,2-dioxygenase (CbeABC) is 50-65% identical to the benzoate dioxygenase (BenABC) of Acinetobacter sp. ADP1, toluate dioxygenase (XylXYZ) of the TOL plasmid pWW0 and 2-halobenzoate dioxygenase (CbdABC) of Burkholderia cepacia 2CBS. Disruption of the cbeA gene resulted in the simultaneous loss of the ability to grow on benzoate and monochlorobenzoates, indicating the involvement of the cbeABCD genes in the degradation of these aromatics. The cbeABCD genes are preceded by catA, the gene for catechol dioxygenase. lacZ transcriptional fusion studies in Pseudomonas putida showed that catA and cbeA are co-expressed under the positive control of cbeR, a LysR-type transcriptional regulatory gene. The cbeA::lacZ transcriptional fusion studies showed that the inducers of the genes are 3CB, 4CB, benzoate and probably cis,cis-muconate. On the other hand, 2-chlorobenzoate (2CB) did not activate the expression of the genes. The chlorobenzoate dioxygenase was able to transform 2CB, 3CB, 4CB and benzoate at considerable rates. 2CB yielded both catechol and 3-chlorocatechol (3CC), and 3CB gave rise to 4-chlorocatechol and 3CC as the major and minor intermediate products, respectively, indicating that the NK8 dioxygenase lacks absolute regiospecificity. The absence of growth of NK8 on 2CB, despite its considerable degradation activity against 2CB, is apparently due to the inability of CbeR to recognize 2CB as an inducer of the expression of the cbe genes.

Sequence analysis and expression of the P450 aromatase and estrogen receptor genes in the Xenopus ovary

Recent studies point to a key role for the estrogen synthesizing enzyme P450 aromatase (P450 arom) in ovary determination in fish, birds and reptiles. It is unclear whether estrogen synthesis is important in sex determination of Xenopus gonad. To determine whether the aromatase gene is transcribed in the gonads of Xenopus tadpoles during the sex determination, we cloned a P450 arom cDNA and examined the level of P450 arom and estrogen receptor (ER) gene expression in association with estrogen activity. cDNA clones for P450 arom were isolated from a Xenopus ovarian cDNA library. There was an open reading frame (ORF) of 1500 bp from the ATG start to TAA stop codons encoding 500 predicted amino acids. cDNAs for P450 arom have previously been cloned from various vertebrates. The homology between the Xenopus P450 aromatase and the human P450 arom was higher. The expression of the P450 arom gene was mainly limited to reproductive organs. To determine the beginning of estrogen activity in gonads of embryos, expression of the aromatase and ER gene was also examined by RQ-RT-PCR. Both Xenopus aromatase and ER mRNA was detected at stage 51 in gonads. These observations are consistent with estrogens having a key role in ovarian development in various other vertebrates.

[An autopsy case of dementia with Lewy bodies who showed the typical parkinsonism in the initial five years]

A 76-year-old man with parkinsonism and dementia was reported. He developed resting tremor at age 69 followed by hypokinesia, rigidity and small step gait. L-dopa ameliorated his symptoms with no hallucinations for the initial 5 years. His mental level did not decrease during that period. He was admitted to our hospital because of dehydration and fever at age 74. Subsequently, his cognitive function deteriorated, with visual hallucination. Serial brain CT studies displayed a progressive cerebral cortical atrophy without focal lesions. He died of respiratory distress syndrome and disseminated coagulopathy resulting from pneumonia, dehydration and syndrome malin. Postmortem examination revealed a marked bilateral loss of melanin-containing neurons with Lewy bodies in the substantia nigra and locus ceruleus. Lewy bodies were also in the basal nucleus of Meynert, with moderate neuronal cell loss. The distribution of Lewy bodies was widespread in the cerebral cortical areas, corresponding to the neocortical subtype according to the consensus guideline for the pathologic diagnosis of dementia with Lewy bodies. According to the criteria of the Consortium to Establish a Registry for Alzheimer's Disease, the age-related plaque score in the present case suggested Alzheimer's disease, although cortical neurofibrillary changes corresponded to stage II by the criteria of Braak and Braak. These pathological findings established the diagnosis of dementia with Lewy bodies from the quantitative and distributional viewpoints. Based on recent neuropathological evidence, a spectral theory, which presents idiopathic Alzheimer's disease and Parkinson's disease as the two extremes of a spectrum of neurodegeneration, has been proposed. Dementia with Lewy bodies is located in the middle of this spectrum. Pathological evaluation based on quantitative consensus guidelines is important to establish the diagnosis in patients with parkinsonism and dementia, since neuropathological changes of Alzheimer's disease, Parkinson's disease and dementia with Lewy bodies are often observed in a mixed manner in these patients.

Exercise BP response in subjects with high-normal BP: exaggerated blood pressure response to exercise and risk of future hypertension in subjects with high-normal blood pressure

OBJECTIVES

This study was designed to assess the clinical usefulness of an exaggerated blood pressure (BP) response to exercise (EBPR) in predicting the development of hypertension from a high-normal state.

BACKGROUND

Exaggerated BP response during both dynamic and isometric exercises are associated with increased risk of future hypertension, while the significance of these responses concerning the identification of individuals with high-normal BP who are prone to develop hypertension is unknown.

METHODS

The study population comprised a sample of 239 men with high-normal BP (aged 42.3 +/- 5.9 years) who underwent a symptom-limited bicycle ergometer exercise testing at baseline and then were followed for 5.1 years.

RESULTS

The Kaplan-Meier survival analysis showed that the subjects in the upper quartile of BP response to exercise had a significantly higher cumulative incidence of hypertension on follow-up than those in the middle two and lower quartiles (log-rank test, p < 0.05). Multivariate analysis using the Cox proportional hazards survival model showed that the EBPR was significantly and independently associated with the risk of developing hypertension after adjustment for some traditional risk factors for hypertension (RR = 2.31, 95% confidence interval = 1.45 to 6.25).

CONCLUSIONS

These findings suggest that an EBPR is an important risk factor for new-onset hypertension from a high-normal state and, thus, exercise testing can provide valid information that may help identify individuals with high-normal BP at a greater risk of future hypertension.

Walking 10,000 steps/day or more reduces blood pressure and sympathetic nerve activity in mild essential hypertension

We investigated the effects of walking 10,000 steps/day or more on blood pressure and cardiac autonomic nerve activity in mild essential hypertensive patients. All subjects were males aged 47.0+/-1.0 (mean+/-SEM) years old. The original cohort consisted of 730 people in a manufacturing industry who measured the number of steps they walked each day using a pedometer. Eighty-three of these subjects walked 10,000 steps/day or more for 12 weeks. Thirty-two of these were hypertensives with systolic blood pressure (SBP) greater than 140 mmHg and/or diastolic blood pressure (DBP) greater than 90 mmHg. Thirty of these hypertensive subjects (HT) were examined twice, once during the pre- and once during the post-study period, for body mass index (BMI), maximal oxygen intake (Vo2max), blood pressure, heart rate (HR), and autonomic nerve activity by power spectral analysis of SBP and HR variability. In the HT group, walking 13,510+/-837 steps/day for 12 weeks lowered blood pressure (from 149.3+/-2.7/98.5+/-1.4 to 139.1+/-2.9/90.1+/-1.9 mmHg; p<0.01, respectively). In both the 34 normotensive controls and 17 hypertensive sedentary controls, blood pressure did not change. Walking also significantly lowered low-frequency fluctuations in SBP as an index of sympathetic nerve activity, from 1.324+/-0.192 to 0.738+/-0.154 mmHg2/Hz (p<0.05). VO2max rose significantly from 26.1+/-2.4 to 29.5+/-2.5 ml/kg/min (p<0.05). There were no changes in parasympathetic nerve activity, baroreceptor reflex sensitivity, or BMI. Our results indicate that walking 10,000 steps/days or more, irrespective of exercise intensity or duration, is effective in lowering blood pressure, increasing exercise capacity, and reducing sympathetic nerve activity in hypertensive patients.

Mesangial expression of a nonmuscle myosin heavy chain, SMemb, is associated with glomerular sclerosis and renal prognosis in IgA nephropathy

To characterize the phenotypic alteration in mesangial cells in human glomerulonephritis, we investigated the expression of nonmuscle-type myosin heavy chain, SMemb, and alpha-smooth muscle actin (alpha-SM actin) in IgA nephropathy. The expression of SMemb and alpha-SM actin was examined by immunohistochemistry in biopsy specimens from 45 patients with IgA nephropathy. We examined a total of 489 glomeruli representing all patients enrolled, and found that mesangial expression of SMemb and alpha-SM actin was associated with mesangial proliferation. Only mesangial expression of SMemb showed a significant relationship with mesangial matrix accumulation. Semiquantitative evaluation using composite expression scores showed that the expression of SMemb was elevated in the patients with poor renal prognosis. The expression of alpha-SM actin showed no significant relationship with renal prognosis. These results suggest that mesangial expression of SMemb is an important factor in the progression of IgA nephropathy, and that SMemb and alpha-SM actin are associated with the activation of mesangial cells by different mechanisms.

6-(hydroxyalkyl)penicillanates as probes for mechanisms of beta-lactamases

6-(Hydroxyalkyl)penicillanates have proven helpful as probes for the mechanisms of beta-lactamases, enzymes of resistance for beta-lactam antibiotics. The present report summarizes the concepts on design, syntheses and use of these molecules in mechanistic studies of beta-lactamases.

[Complications related to arterial infusion chemotherapy in patients with hepatic metastasis from colorectal cancer]

Complications of hepatic arterial infusion chemotherapy were analyzed in 30 cases with hepatic metastasis from colorectal cancer from July 1993 to February 2000 in our department. Thirty patients were treated with three kinds of arterial infusion course that mainly consisted of 5-FU. Complications resulting in interruption of therapy occurred in 10 patients (33%), and there was no difference in the incidence rate of complications among the three chemotherapy regimens. The complications with our therapy were hepatic arterial occlusion in two patients, catheter tip dislocation in four patients, fistulus between the hepatic artery and common bile duct in two patients, and fistulus between the hepatic artery and duodenal bulb in two patients. Four patients who had severe complications with fistulus all underwent hepatectomy, especially right hepatic lobectomy in two cases. Sixty percent of our patients had complications after hepatectomy, so regular GIF and DSA are necessary to prevent severe complications after hepatectomy.

Stereoselective reduction of alpha-bromopenicillanates by tributylphosphine

[reaction: see text] Diastereoselective reduction of 6-bromo-6-substituted penicillanate esters has been achieved by treatment with tributylphosphine to give 6-substituted penicillanate esters. This reaction would appear to proceed through a phosphonium beta-lactam enolate species, followed by a diastereoselective protonation. This method has the advantage of being simple to carry out and it is mild, gives high diastereoselectivity, and should tolerate a number of functional groups in the substrates. Implications of these observations are discussed.

[A case of adenoid cystic carcinoma of the trachea resected surgically after Nd-YAG laser therapy]

A case of primary tracheal tumor ablated by endoscopic Nd-YAG laser prior to tracheal sleeve resection was reported. A 53-year-old man had dry cough, bloody sputum and dyspnea. Bronchoscopic examination revealed polypoid tumor which located 2 cm below the vocal cords and obstructed the airway almost completely. After tumor vaporized by Nd-YAG laser, bronchoscopy type 200 could pass through the tracheal lumen and the length of the lesion was diagnosed within 4 cm. Biopsy specimen was confirmed adenoid cystic carcinoma. Cervical trachea was resected of six tracheal cartilage (first to sixth cartilage) combined with left thyroid lobe under collar incision and median sternotomy. The neck was fixed for ten days by tying the jaw to the anterior chest wall in order to reduce excessive tension to the anastomosis. Pathological examination revealed the tumor residual microscopically, 60 Gy of radiotherapy was conducted.

A complex insertion sequence cluster at a point of interaction between the linear plasmid SCP1 and the linear chromosome of Streptomyces coelicolor A3(2)

The giant linear plasmid SCP1 can integrate into the central region of the linear chromosome of Streptomyces coelicolor A3(2). Nucleotide sequence analysis around the target site for SCP1 integration in strain M145 identified a total of five copies of four insertion sequences (ISs) in a 6.5-kb DNA stretch. Three of the four (IS468, IS469, and IS470) are new IS elements, and the other is IS466. All of these elements contain one open reading frame which encodes a transposase-like protein. Two copies of IS468 (IS468A and -B) are tandemly aligned at the left end of the cluster. Following these, IS469 and IS466 are located in a tail-to-tail orientation with 69.3% identity to each other. IS470 is located at the right end of the cluster. The activities of IS466 and IS468 were demonstrated by transposition experiments and sequence comparison of several copies, respectively.

Increased extra domain-A containing fibronectin and hepatic dysfunction during septic response: an in vivo and in vitro study

A massive inflammatory reaction resulting from systemic cytokine release is the common pathway underlying sepsis or multiple organ dysfunction. The role of extra domain sequence A-containing fibronectin (EDA+FN) formation during the septic response is not known. The present study investigates the role of EDA+FN during the septic response under in vitro and in vivo conditions. The direct effects of interleukin-1, interleukin-6, and tumor necrosis factor-alpha on EDA+FN production were evaluated in primary cultured human hepatocytes and fibroblasts. Serial plasma EDA+FN levels were measured using an enzyme-linked immunosorbent assay in 24 patients who developed postoperative sepsis following general abdominal surgery of which there were 17 survivors and 7 non-survivors. EDA+FN secretion was significantly increased in cultured hepatocytes but not fibroblasts at 24 and 48 h following exposure to IL-1 compared to controls. In the clinical setting plasma EDA+FN levels in non-survivors were significantly higher than in survivors. Moreover, the EDA+FN levels were correlated closely with liver function tests. EDA+FN levels may represent a specific marker of vascular injury or systemic inflammatory response syndrome that is associated with an adverse clinical outcome.

Evaluation of combined effect of organic solvents and noise by the upper limit of hearing

To clarify the combined effects of organic solvents and noise on hearing, the upper limit of hearing was measured in 48 male workers exposed to organic solvents and/or noise in a factory producing plastic buttons. Measuring the organic solvent concentrations in working environments and breathing zone air, and the noise level in workplaces were also done. The readings suggested that most exposures to organic solvents and/or noise were within the occupational exposure limits. The prevalence rate of the upper limit of hearing below 75th percentile curve was higher in workers exposed to organic solvents and noise than expected (25 percent) and the other groups, whereas it was about 25 percent in the noise and control groups. The results suggest that the probable combined effects of organic solvents and noise on hearing should be considered even when the exposures are within the occupational exposure limits.

Evaluation of intracranial pressure by transcranial Doppler ultrasonography in dogs with intracranial hypertension

Transcranial Doppler ultrasonography (TCD) has been used to confirm changes in cerebral hemodynamics. In this study, we investigated whether the parameters for the basilar artery measured by TCD were correlated with the intracranial and cerebral perfusion pressures in extreme intracranial hypertension. An intracranial hypertension model was produced in seven dogs by inflating a balloon inserted into the epidural space. The resistance index was compared with the corresponding intracranial pressure and cerebral perfusion pressure values during intracranial hypertension. A significant correlation was recognized between the resistance index and cerebral perfusion pressure. Therefore, measurement of the basilar artery by TCD in the dog with intracranial hypertension is useful in estimating the intracranial circulation in cases where the measurement of intracranial pressure is not available or not indicated.

Induction and repression of a Streptomyces lividans chitinase gene promoter in response to various carbon sources

Induction and repression of a gene for chitinase (chiA) in Streptomyces lividans was investigated using a catechol 2,3-dioxygenase gene (xylE) as the reporter gene. Of various substrates examined, expression of the promoter (PchiA) was observed after a delay when colloidal chitin or small chitin-oligosaccharides were added to the medium. N-acetylglucosamine completely repressed the chiA promoter. The duration of the delay in expression of PchiA differed with the inducer used, with chitobiose inducing the activity most rapidly. The minimum concentration of chitobiose needed for induction was 1 microM. It appears, therefore, that an efficient inducer of the gene for chitinase in S. lividans is chitobiose.

Transcriptional activation of the chlorocatechol degradative genes of Ralstonia eutropha NH9

Ralstonia eutropha (formerly Alcaligenes eutrophus) NH9 degrades 3-chlorobenzoate via the modified ortho-cleavage pathway. A ca. 5.7-kb six-gene cluster is responsible for chlorocatechol degradation: the cbnABCD operon encoding the degradative enzymes (including orfX of unknown function) and the divergently transcribed cbnR gene encoding the LysR-type transcriptional regulator of the cbn operon. The cbnRAB orfXCD gene cluster is nearly identical to the chlorocatechol genes (tcbRCD orfXEF) of the 1,2, 4-trichlorobenzene-degrading bacterium Pseudomonas sp. strain P51. Transcriptional fusion studies demonstrated that cbnR regulates the expression of cbnABCD positively in the presence of either 3-chlorobenzoate or benzoate, which are catabolized via 3-chlorocatechol and catechol, respectively. In vitro transcription assays confirmed that 2-chloro-cis,cis-muconate (2-CM) and cis, cis-muconate (CCM), intermediate products from 3-chlorocatechol and catechol, respectively, were inducers of this operon. This inducer-recognizing specificity is different from those of the homologous catechol (catBCA) and chlorocatechol (clcABD) operons of Pseudomonas putida, in which only the intermediates of the regulated pathway, CCM for catBCA and 2-CM for clcABD, act as significant inducers. Specific binding of CbnR protein to the cbnA promoter region was demonstrated by gel shift and DNase I footprinting analysis. In the absence of inducer, a region of ca. 60 bp from position -20 to position -80 upstream of the cbnA transcriptional start point was protected from DNase I cleavage by CbnR, with a region of hypersensitivity to DNase I cleavage clustered at position -50. Circular permutation gel shift assays demonstrated that CbnR bent the cbnA promoter region to an angle of 78 degrees and that this angle was relaxed to 54 degrees upon the addition of inducer. While a similar relaxation of bending angles upon the addition of inducer molecules observed with the catBCA and clcABD promoters may indicate a conserved transcriptional activation mechanism of ortho-cleavage pathway genes, CbnR is unique in having a different specificity of inducer recognition and the extended footprint as opposed to the restricted footprint of CatR without CCM.

A study on the effects of countermeasures for vibrating tool workers using an impact wrench

The aims of this study were (1) to measure frequency-weighted vibration acceleration and (2) to study the effects of introducing a vibration-proof impact wrench on VWF in workers. The subject pool was 383 male workers who were regularly using an impact wrench and taking special medical examinations for vibration syndrome in a factory from 1982 to 1999. The prevalence of workers with VWF increased gradually after 1982, reached a peak value (4.8%) in 1986, gradually decreased after 1987, and disappeared in 1994. Sixteen subjects who had had VWF at least one time during the observation period were selected for this study. The stages of VWF were at stage I on the Stockholm Workshop scale in all subjects. After the vibration-proof impact wrench was introduced in 1986, the vibration acceleration of the impact wrench measured on the handle decreased from 8.6-11.1 m/s2 to 5.1-7.1 m/s2. The actual time per day that subjects were assumed to use the impact wrench was 108 minutes. The subjects actually used an impact wrench more than the occupational exposure limit allowed. However, VWF disappeared after the introduction of a vibration-proof impact wrench. This might have resulted from the combined effect of introducing the vibration-proof impact wrench and certain countermeasures that were taken against cold working environments.