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Biomedical subjects

T Beppu

Publications and source records attributed to T Beppu.

At least 253 records · Page 14Linked to original sources
PubMed1989

Detection and properties of A-factor-binding protein from Streptomyces griseus.

The optically active form of tritium-labeled A-factor (2-isocapryloyl-3R-hydroxymethyl-gamma-butyrolactone), a pleiotropic autoregulator responsible for streptomycin production, streptomycin resistance, and sporulation in Streptomyces griseus, was chemically synthesized. By using the radioactive A-factor, a binding protein for A-factor was detected in the cytoplasmic fraction of this organism. The binding protein had an apparent molecular weight of approximately 26,000, as determined by gel filtration. Scatchard analysis suggested that A-factor bound the protein in the molar ratio of 1:1 with a binding constant, Kd, of 0.7 nM. The number of the binding protein was roughly estimated to be 37 per genome. The "inducing material" virginiae butanolide C (VB-C), which has a structure very similar to that of A-factor and is essential for virginiamycin production in Streptomyces virginiae, did not inhibit binding. In addition, no protein capable of specifically binding 3H-labeled VB-C was found in S. griseus. Together with the observation that VB-C had almost no biological activity on the restoration of streptomycin production or sporulation in an A-factor-deficient mutant of S. griseus, these results indicated that the binding protein had a strict ligand specificity. Examination for an A-factor-binding protein in Streptomyces coelicolor A3(2) and Streptomyces lividans showed the absence of any specifically binding protein.

4-Butyrolactone↗
PubMed1989

Feasibility of non-invasive measurement of the left ventricular max (dp/dt) by continuous recording of the ascending aortic diameter change: principle and experimental study.

If a method produces a pressure contour with an arbitrary relative amplitude and without a base line, i.e. a pressure tracing without scale, and another method gives two out of the following three values: peak; bottom; and mean pressures, then we can obtain a pressure contour with a specified pressure scale. We can also obtain the value of the derivative of pressure with respect to time. If the curve of the ascending aortic diameter change closely resembles the pressure contour at the same portion (assumption 1), we can obtain the aortic pressure contour with an arbitrary pressure scale measuring the aortic diameter by a non-invasive ultrasonic method. The aortic peak systolic, end-diastolic and mean pressures can be measured by other non-invasive methods. Therefore, we can specify the pressure scale of the contour, and obtain the maximum derivative of the aortic pressure. If the maximum derivative of the left ventricular pressure (max dp/dt) can be substituted by that of the aortic pressure (assumption 2), we can obtain the former (max dp/dt) by non-invasive measurements only. We confirmed assumptions 1 and 2 by animal experiments, and showed the feasibility of non-invasive measurements of the left ventricular max (dp/dt) by interpreting the aortic diameter change curve as the pressure contour.

Animals↗
PubMed1989

Percutaneously adjustable pulmonary artery band. An experimental study.

Several forms of congenital heart lesions with increased pulmonary flow can be effectively palliated by pulmonary artery banding. In addition, banding has aroused renewed interest to induce left ventricular hypertrophy in infants with simple transposition of the great arteries. Occasionally a need arises to readjust the band to obtain an optimal degree of banding after operation. For percutaneous control of the degree of constriction after pulmonary artery banding, we developed a readjustable vessel occluder. The occluder consists of a stainless steel snare coated with polyethylene, an enveloping polyvinyl catheter (5F and 8 to 12 cm in length), and a screw adjuster, which is a stainless steel cylinder, 7 by 20 mm, containing a bolt and a nut. By means of a specially designed needle driver (1.0 mm in diameter), the screw adjuster can easily be driven percutaneously without a skin incision. The maximum stroke of the screw is 14 mm by 34 revolutions. One complete revolution of this screw corresponds to a change in diameter of 0.14 mm and to a change in circumference of 0.44 mm. Six mongrel dogs ranging in weight from 5 to 10 kg underwent banding of the pulmonary artery or the ascending aorta with this device. Follow-up evaluation by cardiac catheterization and angiocardiography was performed up to 2 months after implantation of the device. This band could be effectively and finely adjusted up to 2 months after implantation and no complication was seen. This preliminary study suggests that this new device may be applicable in patients with congenital heart disease and excessive pulmonary blood flow.

Animals↗
PubMed1989

[Clinical study on the effects of assist bypass on left ventricular contractility].

This study was undertaken to evaluate the effects of circulatory support on cardiac function in 7 patients. They were 2 men and 5 women with of age 34-54 years; Six patients underwent mitral valve replacement and one had mitral valve plasty. End-systolic pressure/volume (ESP/ESV) representing left ventricular contractility was measured just before ECC starting and after cardiac beating began in the process of rewarming. Measurements were repeated at every, interval of 10 minutes up to 60 minutes. ESP/ESV (mmHg/ml) [% of that before ECC] were as following; before ECC: 1.69 +/- 0.68 (mean +/- SD) [100], after 10 minutes; 0.40 +/- 0.24 [25.1 +/- 13.8], after 20 minutes; 0.52 +/- 0.26 [31.5 +/- 12.9], after 30 minutes; 0.77 +/- 0.28 [47.6 +/- 10.5], after 40 minutes; 0.97 +/- 0.26 [60.5 +/- 11.3], after 50 minutes; 1.18 +/- 0.46 [70.6]8.0], after 60 minutes; 1.36 +/- 0.56[80.4 +/- 12.7]. It took 39.6 minutes to recover up to 69% of that before ECC. These data suggested that the myocardial ischemia associated with aortic cross clamping continued for at least 60 minutes after cardiac beating resumed. We concluded that assist bypass should be applied to those who could not be weaned from ECC despite adequate use of catecholamine and volume loading.

Adult↗
PubMed1988

Cloning and expression in Escherichia coli of two additional amylase genes of a strictly anaerobic thermophile, Dictyoglomus thermophilum, and their nucleotide sequences with extremely low guanine-plus-cytosine contents.

An obligately anaerobic and extremely thermophilic bacterium, Dictyoglomus thermophilum, produces multiple extracellular amylases. In addition to one of the amylase genes, amyA, which we previously cloned and characterized, we have cloned two additional genes, amyB and amyC, coding for amylases of this thermophile, into Escherichia coli and determined their nucleotide sequences. The two amylase genes were expressed under the control of E. coli promoters. Almost all activity was detected in the intracellular fraction in the E. coli cells. The molecular mass and NH2-terminal amino acid sequence of the AmyB enzyme, which was purified from an E. coli transformant containing the amyB gene, confirmed that the reading frame of amyB consisted of 562 amino acids (Mr 67,000). The molecular mass of the AmyC enzyme, estimated by activity staining of a crude extract of E. coli containing amyC, confirmed that AmyC consisted of 498 amino acids (Mr 59,000). The optimal temperatures for AmyB and AmyC activities on soluble starch were 80 degrees C and 70 degrees C, respectively. Both AmyB and AmyC showed a pH optimum of 5.5. AmyB and AmyC showed a different pattern of starch hydrolysis when examined by thin-layer chromatography. Some homology in the amino acid sequences with the functional regions of Taka-amylase A was found in both AmyB and AmyC. The codon usage in the amyA, amyB and amyC genes was highly biased, which reflects the fact that the guanine-plus-cytosine (G + C) content of DNA of D. thermophilum is 29 mol%. The distribution of G and C at each position of the codons was non-random; the G + C content of the first position of codons is significantly high, whereas that of the third position is somewhat low. In addition, codons consisting only of A and T were preferentially used in this thermophile.

Amino Acid Sequence↗
PubMed1988

Cloning and nucleotide sequence of a cellulase gene, casA, from an alkalophilic Streptomyces strain.

A gene encoding an endo-type semi-alkaline cellulase was cloned from an alkalophilic Streptomyces strain in Streptomyces lividans, and its nucleotide sequence was determined. Downstream from the transcriptional start point, which was determined by high-resolution S1 mapping, an open reading frame of 388 amino acids (aa) was present. The N-terminal amino acid sequence of the mature enzyme determined by an Edman degradation procedure suggested that the cellulase had an extraordinarily long leader sequence of about 70 aa. Comparison with the leader sequences of endoglucosidase H from Streptomyces plicatus and the cellulase from Cellulomonas fimi suggested that the semi-alkaline cellulase was processed in two steps during maturation.

Amino Acid Sequence↗
PubMed1988

Cloning and nucleotide sequence of a heat-stable amylase gene from an anaerobic thermophile, Dictyoglomus thermophilum.

A highly heat-stable amylase gene from an obligately anaerobic and extremely thermophilic bacterium, Dictyoglomus thermophilum, was cloned and expressed in Escherichia coli. The nucleotide sequence of the amylase gene predicts a 686-amino-acid protein of relative molecular mass 81,200, which is consistent with that determined by sodium dodecyl sulfate/polyacrylamide gel electrophoresis of the purified enzyme. The NH2-terminal sequence determined using the enzyme purified from E. coli cells corresponds precisely to that predicted from the nucleotide sequence, except for the absence of the NH2-terminal methionine in the mature protein. When the amylase gene was expressed in E. coli cells, the enzyme was localized in the cytoplasmic fraction; this is probably explained by the absence of the signal sequence for secretion. By using the amylase purified from the E. coli transformant, some enzymatic properties, such as optimum pH, optimum temperature, pH-stability and heat-stability, were examined. The amylase was found to be a highly liquefying-type.

Amino Acid Sequence↗
PubMed1988

Reversible arrest of proliferation of rat 3Y1 fibroblasts in both the G1 and G2 phases by trichostatin A.

Proliferation of rat 3Y1 cells was found to be specifically blocked by trichostatin A (TSA) at two distinct stages in the cell cycle. The first block occurred in the early G1 phase at least 9 h before the G1/S boundary, whereas the second occurred during the G2 phase. When TSA-arrested cells at the G2 phase were released from the inhibition, the cells with 4C DNA entered a new S phase without passage through the M phase, resulting in the formation of proliferative tetraploid cells. The removal of TSA induced a rapid transient increase in the transcription of c-fos and the cells required 15 h to enter the S phase after release. These results suggest that the cells arrested with TSA are quiescent (G0).

Animals↗
PubMed1988

Hepatic clearances of antipyrine, indocyanine green, and galactose in normal subjects and in patients with chronic liver diseases.

Blood clearance of antipyrine, indocyanine green, and galactose were measured to evaluate the alterations of effective hepatic blood flow and hepatic intrinsic clearances in chronic liver diseases. Galactose blood clearance, which may be taken as effective hepatic blood flow, decreased by approximately 30% in patients with cirrhosis (12.49 +/- 0.76 ml/min/kg; mean +/- SE; n = 17) compared with normal subjects (18.17 +/- 1.03 ml/min/kg; n = 5). In patients with cirrhosis, intrinsic clearances of antipyrine (0.178 +/- 0.014 ml/min/kg; n = 17) and indocyanine green (6.19 +/- 1.38 ml/min/kg; n = 7) showed 61% and 85% reduction, respectively, compared with those of normal subjects (0.462 +/- 0.048 ml/min/kg; n = 5; 41.72 +/- 7.75 ml/min/kg; n = 5). Considering that indocyanine green and antipyrine are eliminated by different hepatic mechanism, these mechanisms may not be equally sensitive to decrements in hepatic function. In addition, fractional reductions of intrinsic clearances for these compounds are thus much greater than that of effective hepatic blood flow.

Adult↗
PubMed1988

Effect of B-factor and its analogues on rifamycin biosynthesis in Nocardia sp.

B-Factor, 3'-(1-butylphosphoryl)adenosine, which was isolated from yeast extract, is an inducer of rifamycin production in a rifamycin non-producing Nocardia mutant. Feeding of B-factor to the mutant culture demonstrated that the induction process was triggered during early stationary phase. Rifamycin production in the mutant was also induced by an exogenous supply of 3-amino-5-hydroxybenzoic acid, an intermediate of the antibiotic pathway, suggesting that a step upstream from the intermediate is regulated by B-factor. B-Factor analogues, i.e., alkylesters of 3'-AMP with alkyl side chains of C(2) approximately C(12) and n-butyl esters of 3'-GMP and 2'-AMP all showed the B-factor activity. Among these n-octyl ester of 3'-AMP showed the lowest effective concentration of approximately 3 x 10(-10) M. An intrinsic substance of the Nocardia sp. with potent B-factor activity and a UV absorption maximum at 260 nm was isolated from the cells of the parental strain.

Adenosine Monophosphate↗
PubMed1987

Effects of trichostatins on differentiation of murine erythroleukemia cells.

The fungistatic antibiotics trichostatins (TS) A and C were isolated from culture broth of Streptomyces platensis No. 145 and were found to be potent inducers of differentiation in murine erythroleukemia (Friend and RV133) cells at concentrations of 1.5 X 10(-8) M for TSA and 5 X 10(-7) M for TSC. Differentiation induced by TS was cooperatively enhanced by UV irradiation but not by treatment with dimethyl sulfoxide. This enhanced activity was completely inhibited by adding cycloheximide to the culture medium 2 h after exposure to TS, suggesting that TS are dimethyl sulfoxide-type inducers of erythroid differentiation. No inhibitory effect of TS was observed on macromolecular synthesis in cultured cells.

Animals↗
PubMed1987

The crystal structure of pseudoazurin from Alcaligenes faecalis S-6 determined at 2.9 A resolution.

The three-dimensional structure of pseudoazurin, a single copper-containing protein from Alcaligenes faecalis strain S-6, has been determined at 2.9 A resolution by X-ray crystallography. The sequences of two other pseudoazurins from Pseudomonas AM1 and Achromobacter cycloclastes may also be accommodated in this structure. The structure, an eight-stranded beta-barrel, resembles closely those of plastocyanin and azurin. It possesses two extra alpha-helices at the C-terminus, whereas azurins have an alpha-helical flap in the middle of their sequences.

Alcaligenes↗
PubMed1987

Nucleotide sequence of a cellulase gene of Bacillus subtilis.

The nucleotide sequence of an endolytic cellulase gene of Bacillus subtilis was determined and compared with the NH2-terminal amino acid sequence of the purified enzyme. The mature protein appeared to be extended by a signal sequence of 36 amino acids. The putative AUG initiation codon was preceded by a sigma 43-type promoter of B. subtilis and an AAGGAGG sequence, typical of procaryotic ribosomal binding sites. Partial homology of amino acid sequences was found between B. subtilis cellulase and an alkalophilic Bacillus cellulase.

Amino Acid Sequence↗
PubMed1987

Secretion of Mucor rennin, a fungal aspartic protease of Mucor pusillus, by recombinant yeast cells.

The aspartic protease gene of a zygomycete fungus Mucor pusillus was expressed in Saccharomyces cerevisiae under the control of the yeast GAL7 promoter. A putative preproenzyme with an NH2-terminal extension of 66 amino acids directed by the gene was processed in yeast cells and the mature enzyme, whose NH2-terminus was identical to that of the Mucor enzyme, was efficiently secreted into the medium at a concentration exceeding 150 mg/l. The enzyme secreted from the recombinant yeast was more glycosylated than the native Mucor enzyme but its enzymatic properties were almost identical with those of the native enzyme, which has been used as a milk coagulant in cheese manufacture.

Amino Acid Sequence↗
PubMed1987

Construction and characterization of multicopy expression-vectors in Streptomyces spp.

A strong transcriptional signal previously cloned from the Streptomyces griseus genome in S. lividans was subcloned and its nucleotide sequence was determined. Upstream of the transcriptional start point which was determined by high-resolution S1 nuclease mapping, -35 (5'-TTGCCG-3') and -10 (5'-TAGCGT-3') sequences, separated by 18 nucleotides, were present. By replacing the tet promoter of pBR322 with the Streptomyces promoter, no expression of the tet gene was observed in Escherichia coli cells. The result suggests that notwithstanding a similarity to the E. coli -35 and -10 sequences, the Streptomyces promoter is not functional in E. coli. The strong promoter was inserted in multi-copy and wide host range plasmids pIJ702 and pKS11, resulting in the pSEV series of expression-vectors with several unique restriction endonuclease cleavage sites downstream of the promoter for cloning of foreign genes. The extremely heat-stable malate dehydrogenase of Thermus flavus, when its coding sequence with a ribosome-binding site was located downstream of the strong promoter in pSEV2, was produced in large quantities in S. lividans throughout growth. When an extracellular cellulase from Bacillus subtilis was expressed in a cellulase-negative S. lividans strain, virtually all of the cellulase activity was found in the culture supernatant.

Bacillus subtilis↗
PubMed1987

Principle of a noninvasive method of measuring Max(dP/dt) of the left ventricle: theory and experiments.

In early systole, before the effects of reflected waves from the periphery become significant, the following equation applies: PA - PO = rho cu (1) where PA and PO are the instantaneous and end-diastolic pressures in the ascending aorta, rho the density of blood, c the velocity of the pulse wave in the aorta, and u the velocity of blood. Differentiation of Eq. (1) with respect to time t yields: dPA/dt = rho c(du/dt) (2) If there is no aortic stenosis, and if the pressure gradient due to the inertia of the blood during acceleration is neglected, the left ventricular pressure P is nearly equal to PA during the ejection period. Since both dP/dt and dPA/dt take their maximum values at times close to the time of aortic valve opening, the following equation applies: Max(dP/dt) not equal to Max(dPA/dt) (3) where Max signifies the maximum value of a derivative. Equation (2) reduces to: Max(dPA/dt) = rho c Max(du/dt) (4) Substitution of Eq. (4) into Eq. (3) yields: Max(dP/dt) not equal to rho c Max(du/dt) (5) Experiments were performed on seven dogs. Max(dP/dt), Max(du/dt), and c were measured during volume loading, pressure loading and unloading, and before and after administration of positive and negative inotropic agents. There was a good linear correlation (Y = 1.01X-2, r = 0.97) between Max(dP/dt) and rho c Max(du/dt). Therefore, Eq. (5) is a universal equation which holds, irrespective of the dogs and interventions employed to change the hemodynamic state.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Serum bile acid profile in thyroid dysfunction and effect of medical treatment.

1. Serum non-esterified bile acid profile was examined in patients with thyroid dysfunction. Sixteen hyperthyroid patients, six hypothyroid patients, nine patients taking thyroid or antithyroid drugs and 26 healthy controls were studied. The medicated patients were euthyroid when serum samples were collected. Bile acid concentration was determined by the simplified microassay method involving mass fragmentation spectrometry. 2. The sum of the concentrations of the individual bile acids was not significantly different among the four groups. However, the composition of bile acid reflected the thyroid function. The most prominent bile acid was deoxycholic acid in the hypothyroid patients and chenodeoxycholic acid in the hyperthyroid patients. The serum bile acid profile of medically treated patients was similar to that of normal controls. The ratio of the sum of deoxycholic and cholic acid to that of lithocholic and chenodeoxycholic acid was found to be a good indicator of thyroid function, while the ratio of cholic acid to chenodeoxycholic acid correlated poorly with it. 3. The characteristic effect of thyroid hormone on the serum bile acid composition in man was the shift from the 'family' of cholic acid to that of chenodeoxycholic acid. This is in agreement with experimental results in the rat, and suggests a specific action of thyroid hormone on the hydroxylating enzymes involved in the conversion of cholesterol into bile acids.

Adolescent↗