Search PubMed⌕ Search

Biomedical subjects

H Himeno

Publications and source records attributed to H Himeno.

82 records · Page 5Linked to original sources
PubMed1989

Discriminator base of tRNA(Asp) is involved in amino acid acceptor activity.

Unmodified E. coli tRNA(Asp) was obtained by in vitro transcription with T7 RNA polymerase from a plasmid carrying a tRNA(Asp) sequence adjacent to the T7 promoter. The transcript exhibited almost the same level of amino acid acceptor activity as intact tRNA(Asp), and the kinetic parameters were also similar. However, substitution of the discriminator base (the fourth base from the 3'-end) markedly affected the amino acid acceptor activity. These results suggest that the discriminator base in tRNA(Asp) plays an important role in the recognition of aspartyl-tRNA synthetase.

Base Sequence↗
PubMed1987

Unusual genetic codes and a novel gene structure for tRNA(AGYSer) in starfish mitochondrial DNA.

The nucleotide sequence of a 3849-bp fragment of starfish mitochondrial genome was determined. The genes for NADH dehydrogenase subunits 3, 4, 5, and COIII, and three kinds of (tRNA(UCNSer), tRNA(His), and tRNA(AGYSer) were identified by comparing with the genes of other animal mitochondria so far elucidated. The gene arrangement of starfish mitochondrial genome was different from those of vertebrate and insect mitochondrial genomes. Comparison of the protein-encoding nucleotide sequences of starfish mitochondria with those of other animal mitochondria suggested a unique genetic code in starfish mitochondrial genome; both AGA and AGG (arginine in the universal code) code for serine, AUA (isoleucine in the universal code but methionine in most mitochondrial systems) for isoleucine, and AAA (lysine) for asparagine. It was also inferred that these AGA and AGG codons are decoded by serine tRNA(AGYSer) originally corresponding to AGC and AGU codons. This situation is similar to the case of Drosophila mitochondrial genome. Variations in the use of AGA and AGG codons were discussed on the basis of the evolution of animals and decoding capacity of various tRNA(AGYSer) species possessing different sizes of the dihydrouridine (D) arm.

Animals↗
PubMed1984

Selective utilization of 2-thioribothymidine- and ribothymidine-containing tRNAs by the protein synthetic systems of Thermus thermophilus HB 8 depending on the environmental temperature.

An extreme thermophile, Thermus thermophilus HB 8, contains two types of tRNAs, T- and S2T-containing tRNAs. Their relative content changes depend on the growth temperature of the bacterial cells (1-3). To elucidate the reason why the extreme thermophile possesses the two types of tRNAs, an attempt was made to clarify how these tRNAs are utilized in in vivo protein synthetic systems of the bacteria cultured at different temperatures. First, a method was developed to isolate active polysomes from the thermophile cells cultured at 55 degrees C, 65 degrees C, and 77 degrees C. Then, tRNAs were separated from the polysomes and the T- and S2T-contents of the tRNAs were determined by HPLC. The relative content of S2T-tRNAs in the polysomes from 77 degrees C cells was much higher than that in bulk tRNAs from whole cells cultured at the same temperature, but the situation was reversed in 50 degrees C cells. These results clearly show that the protein synthetic systems of the thermophile have some selection mechanism to utilize either T- or S2T-containing tRNAs preferentially depending on the environmental temperature.

Bacterial Proteins↗
PubMedDate not supplied

Identity elements of Escherichia coli tRNA(Ala).

Studies using the T7 transcription system revealed that the discriminator base A73 and the G20 in the variable pocket play important roles in the Escherichia coli alanine tRNA identity. The C60 in the T-loop, which is unique to alanine tRNA, was not found to be crucial for alanine identity. Anticodon replacement into the valine anticodon UAC did not decrease alanine charging activity, and no alanine charging activity was detected in the mutant valine tRNA possessing the alanine anticodon UGC.

Base Sequence↗
PubMedDate not supplied

Effect of cilazapril therapy on glucose and lipid metabolism in patients with hypertension.

The effects of long-term monotherapy with cilazapril, an angiotensin-converting enzyme inhibitor, on blood pressure, glucose tolerance, and serum lipid profiles were prospectively investigated in 66 patients with hypertension: 23 with normal glucose tolerance and 43 with glucose intolerance (including 9 patients with non-insulin-dependent diabetes mellitus). The levels of plasma glucose, serum insulin, serum lipids, glycated hemoglobin A(lc) (Hb A(lc)), and fructosamine were determined before and during long-term (mean +/- SD, 26.2 +/- 1.2 weeks) therapy with cilazapril. A 75-g oral glucose tolerance test was performed before and during treatment. Significant reductions in both systolic and diastolic blood pressures in both patient groups were maintained during the study. Neither fasting nor post-glucose load venous plasma glucose levels were altered in either group of patients, and no patient with normal glucose tolerance developed diabetes mellitus during the study. There was no significant change in the insulinogenic index (delta serum insulin/delta venous plasma glucose at 30 minutes post-glucose load) in either group, and glucose intolerance was slightly improved with significant reductions (P < 0.01) in Hb A(lc) and fructosamine in the patient group with impaired glucose tolerance. Serum total cholesterol (TC), low-density lipoprotein cholesterol, and triglyceride levels were significantly (P < 0.01) decreased and high-density lipoprotein cholesterol levels increased in patients with hypercholesterolemia (TC levels > or = 5.69 mmol/L). These results suggest that long-term cilazapril therapy may improve glucose and lipid metabolism in hypertensive patients with impaired glucose tolerance. Cilazapril also appears to be useful as an antihypertensive agent for hypertensive patients with either impaired glucose tolerance or hypercholesterolemia.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

One-day survey of albuminuria in diabetic outpatients in Fukuoka Prefecture, Japan. Fukuoka Diabetic Clinic Group.

The prevalences and risk factors of micro- and macroalbuminuria were surveyed in all 927 patients with diabetes mellitus who visited outpatient clinics in 27 hospitals in the Fukuoka prefecture on a designated day. The urinary albumin-creatinine ratio (UAI; mg/g Cr) of spot urine was determined in all patients except those with persistent macroproteinuria. The results were as follows: (1) The prevalences of microalbuminuria (UAI 30-299) and macroalbuminuria (UAI greater than or equal to 300) were 26% and 15%, respectively. (2) Hyperglycemia and high blood pressure synergistically increased the prevalences. (3) The independent risk factors of microalbuminuria were severities of retinopathy and neuropathy, duration of diabetes, blood pressure, and HbA1c, as determined by logistic regression analysis, although the explanation rate was low.

Albuminuria↗