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251.
Itai A Kotaki T Tanabe K Tamura F Kawaguchi D Fukuda M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,106(7):1266-1272
In Japanese pear (Pyrus pyrifolia Nakai), fruit storage potential is closely related to the amount of ethylene produced. We have developed a rapid and accurate method for analyzing genes involved in high ethylene production during fruit ripening in Japanese pear. This involves cleaved-amplified polymorphic sequences (CAPS) of two 1-aminocyclopropane-1-carboxylate (ACC) synthase genes (PPACS1 and PPACS2). Two CAPS markers (A for PPACS1 and B for PPACS2), associated with the amount of ethylene produced, were identified. Marker A was associated with high ethylene producers and marker B with moderate ethylene producers. The absence of these two markers enabled the identification of low ethylene producers. Using these markers, we have identified ethylene genotypes for 40 Japanese pear cultivars and two Chinese pear (P. bretschneideri) cultivars that are commercially important and used in breeding programs. Furthermore, we performed linkage analysis of these two genes in the F(2) population, which revealed that the recombination frequency between the two markers was 20.8 +/- 3.6%. This information is critical to the selection of parents and in breeding strategies to improve storage ability of Japanese pears. 相似文献
252.
In this issue of Cell, Ishitani et al. (2003) report, in a crystal, a new L-like structure of tRNA designated as lambda-form, where disruption of universal tertiary interactions is compensated by interactions with an enzyme that makes a base modification at the corner of the L. 相似文献
253.
Dietary Zn deficiency does not influence systemic blood pressure and vascular nitric oxide signaling in normotensive rats 总被引:1,自引:1,他引:0
Sato M Kurihara N Moridaira K Sakamoto H Tamura J Wada O Yanagisawa H 《Biological trace element research》2003,91(2):157-171
Because zinc (Zn) is an important component for cell protection against certain oxygen species, it has been suggested that
Zn deficiency impairs the potent oxidant defense capacity, which is constitutively provided in the vascular system. However,
the influence of dietary Zn deficiency on systemic blood pressure and vascular system is controversial and unclear. We therefore
examine the effect of dietary Zn deficiency on systemic blood pressure, a potent superoxide scavenger, aortic Cu/Zn superoxide
dismutase (SOD) activity, a most representative synthase of the endothelium-derived relaxing factor, and aortic endothelial
nitric oxide synthase (eNOS) expression. Furthermore, the direct effects of intravenous administration of NOS inhibitor, N
ω-nitro-l-arginine methyl ester (l-NAME), and a SOD mimetic compound, tempol, in normotensives were tested in Wistar-Kyoto (WKY) rats. A Zn-deficient diet (4
wk) contributed to growth retardation, the decrease in thymus weight, and the lower levels of serum Zn compared with the standard
diet group. However, no significant difference in conscious systolic and diastolic blood pressure was found in the Zn-deficiency
group. The administration of l-NAME caused an increase in the mean arterial pressure (MAP) levels in the two groups of rats and the involvement of the vasodilator
nitric oxide (NO) in the regulation of systemic BP in the normotensive state. On the other hand, administration of the superoxide
scavenger, tempol, led to a decrease in MAP levels in the two groups of rats, indicating the participation of the oxygen free
radical, superoxide, in the maintenance of the systemic BP in a normotensive state. There were no significant differences
between the Zn-deficient diet group and the standard diet group in the normotensive state. eNOS expression and Cu/Zn SOD activity
in the aorta were also intact in Zn-deficient normotensive rats. These findings suggest that the 4 wk of Zn deficiency was
inadequate to alter systemic blood pressure and focal NO signaling in the normotensive state. Long-term Zn deficiency affects
the neuronal, immune, and hematopoietic systems, which contribute to systemic and/or local circulation. However, Zn deficiency
alone does not cause hypertension and local vascular dysfunction in the normotensive state. 相似文献
254.
255.
Masahiko?HirataEmail author Mihoko?Nakagawa Harumi?Funakoshi Takuya?Iwamoto Waka?Otozu Daisuke?Kiyota Shirou?Kuroki Kiichi?Fukuyama 《Journal of Ethology》2003,21(2):161-168
Distance between dam and offspring (1–121 days old) in a herd of Japanese Black cattle (Bos taurus) grazing a tropical grass (Paspalum notatum) pasture (1.5 ha) was investigated during 7-h grazing periods over grazing seasons from May (spring) to October (autumn).
The mother–young distance was not constant throughout the grazing period, repeatedly increasing and decreasing. Although significant
periodicity was always detected in the mother–young distance, there was no consistent dominant cycle, indicating the complexity
of the within-day pattern of mother–young distance. The mean mother–young distance over the grazing period increased as a
calf aged, reaching a plateau at an age of about 33 days. The mean distance of a calf from its mother was usually shorter
than that from a non-mother cow, with the difference between the mean distances decreasing sharply until a calf became about
35 days old. The results and literature show that mutual independence of mother and young rapidly develops in the first 30–50 days
after parturition.
Electronic Publication 相似文献
256.
Tabuchi M Ozaki M Tamura A Yamada N Ishida T Hosoda M Hosono A 《Bioscience, biotechnology, and biochemistry》2003,67(6):1421-1424
Neonatally streptozotocin-induced diabetic (n-STZ) rats were given food containing Lactobacillus GG cells (GG) or a control diet (control), from 9 to 18 weeks of age. The GG cells significantly lowered the blood hemoglobin A(1C) (HbA(1C)) level and improved glucose tolerance in n-STZ rats (p<0.05). In the GG group, the serum insulin level at 30 min after glucose loading was significantly higher than in the control group (p<0.05). 相似文献
257.
Sulfotransferase (ST) activity for 20-hydroxyecdysone (20E) was identified in a larval fat body lysate of the fleshfly, Sarcophaga peregrina, but not in the hemolymph. The activity was highly sensitive to 2,6-dichloro-4-nitrophenol (DCNP) (IC50=0.61 microM), a specific inhibitor of phenol ST (P-ST), but insensitive to triethylamine, a hydroxysteroid ST inhibitor. These results suggest that 20E-specific ST enzymes belong to the P-ST family, despite the fact that 20E is a hydroxysteroid. In addition to 20E ST activity, a relatively high level of 2-naphthol ST activity was detected in the fat body lysate. The ST activity for both substrates transiently decreased to the 50% of maximal levels, 6 hrs after induction of pupation. The ST enzymes were separated on a DEAE-cellulose column. The 20E-ST enzymes were eluted around 50 mM KCl as two separate peaks of close proximity and the P-ST was eluted at 0.1 M KCl. The 20E ST enzymes were further purified using 3'-phosphoadenosine 5'-phosphate (PAP)-agarose affinity column chromatography. Both of the eluted active fractions demonstrated 43-kDa proteins on SDS-polyacrylamide gel. Photoaffinity labeling with [35S]-3'-phosphoadenosine 5'-phosphosulfate (PAPS) showed 43-kDa bands in the fat body lysate, as well as in the purified fractions. These results suggest that the 43-kDa proteins catalyze 20E sulfation within the fat body of S. peregrina. 相似文献
258.
259.
Motoshima H Inagaki K Kumasaka T Furuichi M Inoue H Tamura T Esaki N Soda K Tanaka N Yamamoto M Tanaka H 《Journal of biochemistry》2000,128(3):349-354
L-Methionine gamma-lyase (MGL) catalyzes the pyridoxal 5'-phosphate (PLP) dependent alpha,gamma-elimination of L-methionine. We have determined two crystal structures of MGL from Pseudomonas putida using MAD (multiwavelength anomalous diffraction) and molecular replacement methods. The structures have been refined to an R-factor of 21.1% at 2.0 and 1.7 A resolution using synchrotron radiation diffraction data. A homotetramer with 222 symmetry is built up by non-crystallographic symmetry. Two monomers associate to build the active dimer. The spatial fold of subunits, with three functionally distinct domains and their quarternary arrangement, is similar to those of L-cystathionine beta-lyase and L-cystathionine gamma-synthase from Escherichia coli. 相似文献
260.
Helicobacter pylori, a microaerophilic Gram-negative spiral bacterium residing in the human stomach, contains a small size soluble cytochrome c. This cytochrome c was purified from the soluble fraction of H. pylori by conventional chromatographies involving octyl-cellulose and CM-Toyopearl. Its reduced form gave an alpha absorption band at 553 nm, and thus the cytochrome was named H. pylori cytochrome c-553. The cytochrome, giving a band below 10,000 Da upon SDS-PAGE, was determined to have a mass of 8,998 by time of flight mass spectroscopy. Its N-terminal peptide sequence was TDVKALAKS---, indicating that the nascent polypeptide was cleaved to produce a signal peptide of 19 amino acid residues and a mature protein composed of 77 amino acid residues. The cb-type cytochrome c oxidase oxidized ferrocytochrome c-553 of this bacterium actively (V(max) of about 250 s(-1)) with a small K(m) (0.9 microM). Analysis of the effect of the salt concentration on the oxidase activity indicated that oxidation of cytochrome c-553 is highly inhibited under high ionic conditions. The amino acid sequence of H. pylori cytochrome c-553 showed the closest similarity to that of Desulfovibrio vulgaris cytochrome c-553, and these sequences showed a weak relationship to that of the cytochrome c(8)-group among class I cytochromes c. 相似文献