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51.
The SSR16 gene of Arabidopsis has been identified as a gene encoding a ribosomal protein S16 homolog through analysis of a transposon insertion mutation. The insertion mutation is lethal, arresting embryonic development at approximately the transition from the globular to the heart stage of embryonic development. Co-segregation of the mutant phenotype with the transposon-borne drug-resistance marker and loss of the inserted transposon concomitant with phenotypic reversion provided evidence that the transposon had caused the mutation. Sequences flanking the insertion site were amplified from DNA of viable heterozygotes by thermal asymmetric interlaced (TAIL) PCR. The amplified fragment flanking the 3' end of the inserted element was sequenced and found to be identical to an Arabidopsis expressed sequence tag (EST). The EST, in turn, contained a coding sequence homologous to the ribosomal protein S16 (RPS16) of bacteria such as Escherichia coli, Bacillus subtilis and Salmonella typhimurium , as well as Neurospora crassa mitochondria and higher plant plastids. Thus the gene identified by the embryo-defective lethal insertion mutation encodes an RPS16 homolog and has been designated the SSR16 gene.  相似文献   
52.
In the present study, we examined signal transduction mechanism of reactive oxygen species (ROS) production and the role of ROS in angiotensin II-induced activation of mitogen-activated protein kinases (MAPKs) in rat neonatal cardiomyocytes. Among three MAPKs, c-Jun NH(2)-terminal kinase (JNK) and p38 MAPK required ROS production for activation, as an NADPH oxidase inhibitor, diphenyleneiodonium, inhibited the activation. The angiotensin II-induced activation of JNK and p38 MAPK was also inhibited by the expression of the Galpha(12/13)-specific regulator of G protein signaling (RGS) domain, a specific inhibitor of Galpha(12/13), but not by an RGS domain specific for Galpha(q). Constitutively active Galpha(12)- or Galpha(13)-induced activation of JNK and p38 MAPK, but not extracellular signal-regulated kinase (ERK), was inhibited by diphenyleneiodonium. Angiotensin II receptor stimulation rapidly activated Galpha(13), which was completely inhibited by the Galpha(12/13)-specific RGS domain. Furthermore, the Galpha(12/13)-specific but not the Galpha(q)-specific RGS domain inhibited angiotensin II-induced ROS production. Dominant negative Rac inhibited angiotensin II-stimulated ROS production, JNK activation, and p38 MAPK activation but did not affect ERK activation. Rac activation was mediated by Rho and Rho kinase, because Rac activation was inhibited by C3 toxin and a Rho kinase inhibitor, Y27632. Furthermore, angiotensin II-induced Rho activation was inhibited by Galpha(12/13)-specific RGS domain but not dominant negative Rac. An inhibitor of epidermal growth factor receptor kinase AG1478 did not affect angiotensin II-induced JNK activation cascade. These results suggest that Galpha(12/13)-mediated ROS production through Rho and Rac is essential for JNK and p38 MAPK activation.  相似文献   
53.
Elongation of seminal and lateral roots of rice seedlings was markedly inhibited by high ammonium levels in growth medium. However, high exogenous nitrate concentrations had little inhibitory effect on root growth. The objective of this study was to elucidate the relationship between inhibition of rice root growth induced by high ammonium conditions and ammonium assimilation in the seedlings. Activity of glutamine synthetase (GS) was kept at a low level in the seminal roots of the seedlings grown under high nitrate levels. In contrast, high ammonium levels significantly enhanced the GS activity in the roots, so that Gln abundantly accumulated in the shoots. These results indicate that ammonium assimilation may be activated in the seminal roots under high ammonium conditions. Application of methionine sulfoximine (MSO), an inhibitor of GS, relieved the repression of the seminal root elongation induced by high ammonium concentrations. However, the elongation of lateral roots remained inhibited even under the same condition. Furthermore, MSO drastically increased ammonium level and remarkably decreased Gln level in the shoots grown under high ammonium conditions. These results show that, for rice seedlings, an assimilatory product of ammonium, and not ammonium itself, may serve as an endogenous indicator of the nitrogen status involved in the inhibition of seminal root elongation induced by high levels of exogenous ammonium.  相似文献   
54.
Thymidine phosphorylase (TP) has chemotactic and angiogenic activities resulting from its enzymatic activity in vitro, and it also promotes tumor growth and inhibits apoptosis in vivo. Recently, we have reported that TP plays an important role in Fas-induced apoptosis. Caspase-8 cleavage, subsequent cytochrome c release, and caspase-3 cleavage were prevented in KB cells transfected with a TP cDNA (KB/TP cells). In this study, treatment with thymidine phosphorylase inhibitor (TPI) or thymidine did not affect cell survival of KB/TP cells during Fas-induced apoptosis. Moreover, treatment with thymine or 2-deoxy-D-ribose (degradation products of thymidine generated by TP) also did not affect cell survival of control transfectant (KB/CV) cells during Fas-induced apoptosis. These findings indicate that TP suppresses Fas-induced apoptotic signal transduction independent of its enzymatic activity.  相似文献   
55.
Commonly, 16S ribosome RNA (16S rRNA) sequence analysis has been used for identifying enteric bacteria. However, it may not always be applicable for distinguishing closely related bacteria. Therefore, we selected gyrB genes that encode the subunit B protein of DNA gyrase (a topoisomerase type II protein) as target genes. The molecular evolution rate of gyrB genes is higher than that of 16S rRNA, and gyrB genes are distributed universally among bacterial species. Microarray technology includes the methods of arraying cDNA or oligonucleotides on substrates such as glass slides while acquiring a lot of information simultaneously. Thus, it is possible to identify the enteric bacteria easily using microarray technology. We devised a simple method of rapidly identifying bacterial species through the combined use of gyrB genes and microarrays. Closely related bacteria were not identified at the species level using 16S rRNA sequence analysis, whereas they were identified at the species level based on the reaction patterns of oligonucleotides on our microarrays using gyrB genes.  相似文献   
56.
Oryza rufipogon Griff. is a perennial species of wild rice widely distributed along the channels and rivers of the Mekong Delta, Vietnam. This study attempted to find centers of diversity among wild rice populations in this area and their inter‐relationships. The highest genetic diversity was found in the Dong Thap population and the lowest in the Can Tho population. Maternal diversity evaluated using chloroplast INDELs detected ten plastid types, five of which were novel relative to other Asian countries. The mitochondrial genome suggested two unique deletions. One 699‐bp deletion via short tandem repeats was accompanied by another deletion including orf153. All accessions carrying the mitochondrial type were found in a particular plastid type. This unique maternal lineage was confined to specific channels where it showed vigorous vegetative growth in comparison to upstream areas where various maternal lineages and maximum genetic diversity occurred. This area along the Mekong Delta is a center of not only nuclear but also maternal diversity.  相似文献   
57.
The production of allergen-specific IgE antibodies (Abs) in allergen-sensitized patients or animals has a mutual relationship with the immunologic response leading to allergic rhinitis. We recently reported that, after an intranasal injection of cedar pollen into mice, an interleukin-4 (IL-4)-dependent increase in serum nonspecific IgE Abs was a prerequisite for the production of serum allergen-specific IgE Abs. Here, we explored which lymphoid organs were responsive to the intranasally injected allergen and how IL-4 and IgE Abs were produced in the lymphocytes. Time-dependent changes in the total cell numbers and in in vitro IgE Ab production in various lymphoid organs revealed that the submandibular lymph nodes were the main responsible organ. After treatment with allergen (for IgE production) or allergen and complete Freund's adjuvant (for IgG production), we separated submandibular lymph node cells into macrophage-, lymphocyte-, and granulocyte-rich populations by discontinuous Percoll density-gradient centrifugation. Unexpectedly, bulk cells, but not the lymphocyte- or macrophage-rich populations, produced significant amounts of IL-4, IgE, and IgG; whereas production was restored by addition of Mac-1(+) cells from the macrophage-rich to the lymphocyte-rich fraction. Furthermore, a combination of the lymphocyte-rich population (for IgG [or IgE]) production) and the macrophage-rich population (for IgE [or IgG]) production) produced a large amount of IgE (or IgG). These results indicate that, in the initiation of allergic rhinitis, macrophages in the submandibular lymph nodes are essential not only for IL-4 or immunoglobulin production, but also for class switching of immunoglobulin in lymphocytes.  相似文献   
58.
Increased nitric oxide (NO) production by inducible NO synthase (NOS2), an obligate homodimer, is implicated in the cardiovascular sequelae of sepsis. We tested the ability of a highly selective NOS2 dimerization inhibitor (BBS-2) to prevent endotoxin-induced systemic hypotension, myocardial dysfunction, and impaired hypoxic pulmonary vasoconstriction (HPV) in mice. Mice were challenged with Escherichia coli endotoxin before treatment with BBS-2 or vehicle. Systemic blood pressure was measured before and 4 and 7 h after endotoxin challenge, and echocardiographic parameters of myocardial function were measured before and 7 h after endotoxin challenge. The pulmonary vasoconstrictor response to left mainstem bronchus occlusion, which is a measure of HPV, was studied 22 h after endotoxin challenge. BBS-2 treatment alone did not alter baseline hemodynamics. BBS-2 treatment blocked NOS2 dimerization and completely inhibited the endotoxin-induced increase of plasma nitrate and nitrite levels. Treatment with BBS-2 after endotoxin administration prevented systemic hypotension and attenuated myocardial dysfunction. BBS-2 also prevented endotoxin-induced impairment of HPV. In contrast, treatment with NG-nitro-l-arginine methyl ester, which is an inhibitor of all three NOS isoforms, prevented the systemic hypotension but further aggravated the myocardial dysfunction associated with endotoxin challenge. Treatment with BBS-2 prevented endotoxin from causing key features of cardiovascular dysfunction in endotoxemic mice. Selective inhibition of NOS2 dimerization with BBS-2, while sparing the activities of other NOS isoforms, may prove to be a useful treatment strategy in sepsis.  相似文献   
59.

Objective

HTLV-1 proviral loads (PVLs) and some genetic factors are reported to be associated with the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). However, there are very few reports on HAM/TSP having family history. We aimed to define the clinical features and laboratory indications associated with HAM/TSP having family history.

Methods

Records of 784 HAM/TSP patients who were hospitalized in Kagoshima University Hospital and related hospitals from 1987 to 2012 were reviewed. Using an unmatched case-control design, 40 patients of HAM/TSP having family history (f-HAM/TSP) were compared with 124 patients suffering from sporadic HAM/TSP, who were admitted in series over the last 10 years for associated clinical features.

Results

Of the 784 patients, 40 (5.1%) were f-HAM/TSP cases. Compared with sporadic cases, the age of onset was earlier (41.3 vs. 51.6 years, p<0.001), motor disability grades were lower (4.0 vs. 4.9, p = 0.043) despite longer duration of illness (14.3 vs. 10.2 years, p = 0.026), time elapsed between onset and wheelchair use in daily life was longer (18.3 vs. 10.0 years, p = 0.025), cases with rapid disease progression were fewer (10.0% vs. 28.2%, p = 0.019), and protein levels in cerebrospinal fluid (CSF) were significantly lower in f-HAM/TSP cases (29.9 vs. 42.5 mg, p<0.001). There was no difference in HTLV-1 PVLs, anti-HTLV-1 antibody titers in serum and CSF, or cell number and neopterin levels in CSF. Furthermore, HTLV-1 PVLs were lower in cases with rapid disease progression than in those with slow progression in both f-HAM/TSP and sporadic cases.

Conclusions

We demonstrated that HAM/TSP aggregates in the family, with a younger age of onset and a slow rate of progression in f-HAM/TSP cases compared with sporadic cases. These data also suggested that factors other than HTLV-1 PVLs contribute to the disease course of HAM/TSP.  相似文献   
60.
Organ culture systems are used to elucidate the mechanisms of pattern formation in developmental biology. Various organ culture techniques have been used, but the lack of microcirculation in such cultures impedes the long‐term maintenance of larger tissues. Recent advances in microfluidic devices now enable us to utilize self‐organized perfusable capillary networks in organ cultures. In this review, we will overview past approaches to organ culture and current technical advances in microfluidic devices, and discuss possible applications of microfluidics towards the study of developmental biology.  相似文献   
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