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21.
H. Ichikawa A. Hirai T. Katayama 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1986,72(3):353-358
Summary Relationships in a wide range of Oryza species (13 species) were analyzed using the large subunits (LS) of Fraction I protein (Rubisco) and the Bam HI restriction patterns of chloroplast DNA (ctDNA) as molecular markers. Four types of LS were detected by isoelectrofocusing with and without S-carboxymethylation. The close relation between AA and CCDD genome species was suggested by analyses of LS and ctDNA. Intraspecific variation in O. latifolia was detected at the levels of both LS and ctDNA. The LS of the BB, BBCC, and CC genomes and FF (O. brachyantha) were not distinguishable, although the native Rubisco of the latter was slightly different from those of the first three. It was also shown that O. australiensis, the only EE genome species, might have evolved differently than the other Oryza species. 相似文献
22.
Glomerular mesangium as an effector locus for the tubuloglomerular feedback system and renal sympathetic innervation 总被引:2,自引:0,他引:2
To define the effector loci for the tubuloglomerular feedback system, the determinants of the single-nephron glomerular filtration rate (SNGFR) were assessed in Munich-Wistar rats by direct glomerular puncture during perfusion of Henle's loop with isotonic Ringer's solution at rates of 0 and 40 nl/min. At the higher flow rate, SNGFR averaged only approximately 65% that measured during the lower flow rate. Whereas mean glomerular capillary hydraulic pressure was unaffected, both glomerular plasma flow rate and ultrafiltration coefficient Kf were found to decrease significantly in response to increase in loop perfusion rate, thereby accounting for the measured reduction in SNGFR. These changes were associated with increased afferent (RA) and efferent (RE) arteriolar resistances. Based on the close anatomic contact between mesangial cells and these arterioles, a single effector mechanism channeled through mesangial contractility is suggested to account for the observed reduction in Kf and increase in RA and RE. Mesangial contractility appears to be under sympathetic nerve control. In our recent micropuncture study with Munich-Wistar rats, a marked reduction in SNGFR was observed during high-frequency stimulation (5 Hz) of the renal nerve. This reduction in SNGFR was accompanied by a marked fall in Kf and increase in RA and RE. When kidneys were perfusion-fixed during high-frequency stimulation, a marked reduction in the number of open channels was demonstrated together with marked narrowing of afferent and efferent arterioles. These observations are consistent with the view that sympathetic innervation of mesangium may modulate GFR through its ability to regulate mesangial contractility. 相似文献
23.
Localization of the ribosome-releasing factor gene in the Escherichia coli chromosome. 总被引:4,自引:2,他引:2 下载免费PDF全文
The ribosome-releasing factor (RRF) gene was localized at a position between 2 and 6 min on the Escherichia coli chromosome by measuring the gene-dosage-dependent production of RRF in various E. coli F' merozygotes. This position was confirmed and refined by using a nucleotide probe corresponding to a 16-amino-acid sequence in RRF. It was found that the RRF gene was contained in pLC 6-32 of the Clark-Carbon Gene Bank. Restriction enzyme mapping of E. coli genomic DNA with the above probe led us to conclude that the RRF gene is situated in the 4-min region, somewhere downstream (clockwise) of the elongation factor Ts gene, tsf. A pLC 6-32-derived DNA fragment which carries the RRF gene was found to contain a partial sequence of tsf. The exact location of the translational initiation site of the RRF gene was determined to be 1.1 kilobases downstream from the translational termination site of tsf. The RRF gene is designated frr. 相似文献
24.
A simple and effective procedure for the construction of linear restriction fragment maps was developed. Using a two-enzyme digestion, two-dimensional (2-D) electrophoresis procedure, all the restriction fragments in a 50- to 100-kb DNA can be individually resolved and displayed on a 2-D plane. This 2-D gel pattern, with appropriate markers, provides a fixed set of x, y coordinates for each fragment obtained from the single and double digestion as well as the relationship between the two steps. A matrix is constructed from the 2-D pattern. The vertical column shows all the singly digested individual fragments and their sizes obtained from each restriction enzyme treatment, and the dividing horizontal row shows all the doubly digested DNA fragments and their sizes after treatment with two enzymes. The order of arrangement is always from the smallest to the largest fragments. Using this matrix, two linear DNA restriction maps for these two enzymes can be simultaneously constructed in a self-reconfirming manner. As examples for this procedure, we describe the construction of two linear restriction fragment maps, a combination of EcoRI and BamHI digestion as well as a combination of EcoRI and HindIII digestion of lambda-phage DNA. 相似文献
25.
Reduction of cytochrome P-450S21 (SF) (SF, substrate-free; purified from bovine adrenocortical microsomes) with sodium dithionite (Na2S2O4) in the presence of phenylisocyanide produced a ferrous cytochrome P-450S21 (SF)-phenylisocyanide complex with Soret absorbance maxima at 429 and 456 nm. On the other hand, when a preformed ferric cytochrome P-450S21 (SF)-NADPH-cytochrome-P-450 reductase (Fp2) complex was reduced chemically or enzymatically under the same conditions, the absorbance spectrum of the ferrous cytochrome P-450S21 (SF)-phenylisocyanide complex changed drastically, as characterized by an increase in absorbance intensity at 429 nm and a decrease at 456 nm. Similar spectral changes were observed by addition of reduced Fp2 to the preformed ferrous cytochrome P-450S21 (SF)-phenylisocyanide complex. Experiments to reduce a ferric cytochrome P-450S21 (SF)-phenylisocyanide complex with sodium dithionite in the presence of various amounts of Fp2 showed that; (1), the spectral change reached maxima for both absorption increase at 429 nm and decrease at 456 nm when cytochrome P-450S21 and Fp2 were previously mixed at the cytochrome P-450S21:Fp2 ratio of 1:5; (2), the spectral change was suppressed in 300 mM potassium phosphate buffer (pH 7.4). These results suggest that the absorbance spectral change is due to a conformational change around the heme moiety induced by association with reduced Fp2. 相似文献
26.
27.
A gene at 59 minutes on the Escherichia coli chromosome encodes a lipoprotein with unusual amino acid repeat sequences. 总被引:9,自引:5,他引:4 下载免费PDF全文
We report a 1.432-kb DNA sequence at 59 min on the Escherichia coli chromosome that connects the published sequences of the pcm gene for the isoaspartyl protein methyltransferase and that of the katF or rpoS (katF/rpoS) gene for a sigma factor involved in stationary-phase gene expression. Analysis of the DNA sequence reveals an open reading frame potentially encoding a polypeptide of 379 amino acids. The polypeptide sequence includes a consensus bacterial lipidation sequence present at residues 23 to 26 (Leu-Ala-Gly-Cys), four octapeptide proline- and glutamine-rich repeats of consensus sequence QQPQIQPV, and four heptapeptide threonine- and serine-rich repeats of consensus sequence PTA(S,T)TTE. The deduced amino acid sequence, especially in the C-terminal region, is similar to that of the Haemophilus somnus LppB lipoprotein outer membrane antigen (40% overall sequence identity; 77% identity in last 95 residues). The LppB lipoprotein binds Congo red dye and has been proposed to be a virulence determinant in H. somnus. Utilizing a plasmid construct with the E. coli gene under the control of a phage T7 promoter, we demonstrate the lipidation of this gene product by the incorporation of [3H]palmitic acid into a 42-kDa polypeptide. We also show that treatment of E. coli cells with globomycin, an inhibitor of the lipoprotein signal peptidase, results in the accumulation of a 46-kDa precursor. We thus designate the protein NlpD (new lipoprotein D). E. coli cells overexpressing NlpD bind Congo red dye, suggesting a common function with the H. somnus LppB protein. Disruption of the chromosomal E. coli nlpD gene by insertional mutagenesis results in decreased stationary-phase survival after 7 days. 相似文献
28.
Effects of an antisense napin gene on seed storage compounds in transgenic Brassica napus seeds 总被引:4,自引:0,他引:4
Junko Kohno-Murase Makoto Murase Hiroaki Ichikawa Jun Imamura 《Plant molecular biology》1994,26(4):1115-1124
To manipulate the quantity and quality of storage components in Brassica napus seeds, we have constructed an antisense gene for the storage protein napin. The antisense gene was driven by the 5-flanking region of the B. napus napin gene to express antisense RNA in a seed-specific manner. Seeds of transgenic plants with antisense genes often contained reduced amounts of napin. In some transgenic plants, no accumulation of napin was observed. However, the total protein content of transgenic and wild-type seeds did not differ significantly. Seeds lacking napin accumulated 1.4 to 1.5 times more cruciferin than untransformed seeds, although the oleosin content was not affected. Fatty acid content and composition in the seeds of transgenic plants were also analyzed by gas chromatography. Though the total fatty acid content of the transformants was the same as that of non-transformants, there was a reduction in 18:1 contents and a concomitant increase of 18:2 in seeds with reduced napin levels. This observed change in fatty acid composition was inherited in the next generation. 相似文献
29.
Kazuhiro Ichikawa Yasuyuki Sakai Akiyoshi Sakoda Motoyuki Suzuki 《Biotechnology Techniques》1994,8(6):385-388
Summary Primary culture of rat hepatocytes in hormone-free medium using membrane-supported collagen sandwich maintained their cellular morphology and expressed albumin secretion for about 3 weeks in vitro. It was reconfirmed that mimicking the cellular environment in vivo was effective for cellular maintenance. 相似文献
30.
The molecular basis of increased glomerulosclerosis after blockade of the renin angiotensin system in growth hormone transgenic mice. 总被引:1,自引:0,他引:1 下载免费PDF全文
E. P. Peten L. J. Striker A. Fogo I. Ichikawa A. Patel G. E. Striker 《Molecular medicine (Cambridge, Mass.)》1994,1(1):104-115
BACKGROUND: Angiotensin converting enzyme inhibitor (ACEi) therapy delays the onset of renal failure in diabetic nephropathy and inhibits or delays the onset of proteinuria in several animal models. MATERIALS AND METHODS: We examined this question using a transgenic model of chronic glomerulosclerosis caused by an excess production of growth hormone (GH) in which there is progressive glomerular scarring leading to uremia. In addition, since GH mice do not have systemic hypertension or an elevated glomerular filtration rate, we could address the question of whether ACEi or angiotensin II receptor antagonists (AII RA) had an effect on the development of glomerulosclerosis under these conditions. Since excess matrix accumulates in glomerulosclerosis because of alterations in the balance between its synthesis and degradation, we examined the effect of ACEi and AII RA on these parameters. RESULTS: Systemic blood pressure was unaffected by ACEi treatment, but the glomerular filtration rate decreased 85%. ACEi-treated mice had increased mesangial deposition of type I collagen and decreased 105 kD complex collagenase activity. In addition, ACEi-treated GH mice had increased glomerular alpha 1 type I collagen, alpha 1 type IV collagen, and alpha-smooth muscle cell actin mRNAs. No changes were noted in beta actin, or 72 kD metalloproteinase mRNAs. The result of these changes was a net increase in sclerosis. Surprisingly, GH mice treated with ACEi or AngII RA developed marked renal arteriolar lesions. CONCLUSIONS: In some forms of glomerulosclerosis, the lesions develop independently of angiotensin II. Pharmacological inhibition of angiotensin II, in this circumstance, may aggravate the lesions through disregulation of the levels and the balance between glomerular matrix synthesis and degradation. 相似文献