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The ClpB/Hsp104 chaperone solubilizes and reactivates protein aggregates in cooperation with DnaK/Hsp70 and its cofactors. The ClpB/Hsp104 protomer has two AAA+ modules, AAA-1 and AAA-2, and forms a homohexamer. In the hexamer, these modules form a two-tiered ring in which each tier consists of homotypic AAA+ modules. By ATP binding and its hydrolysis at these AAA+ modules, ClpB/Hsp104 exerts the mechanical power required for protein disaggregation. Although ATPase cycle of this chaperone has been studied by several groups, an integrated understanding of this cycle has not been obtained because of the complexity of the mechanism and differences between species. To improve our understanding of the ATPase cycle, we prepared many ordered heterohexamers of ClpB from Thermus thermophilus, in which two subunits having different mutations were cross-linked to each other and arranged alternately and measured their nucleotide binding, ATP hydrolysis, and disaggregation abilities. The results indicated that the ATPase cycle of ClpB proceeded as follows: (i) the 12 AAA+ modules randomly bound ATP, (ii) the binding of four or more ATP to one AAA+ring was sensed by a conserved Arg residue and converted another AAA+ ring into the ATPase-active form, and (iii) ATP hydrolysis occurred cooperatively in each ring. We also found that cooperative ATP hydrolysis in at least one ring was needed for the disaggregation activity of ClpB. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is as an extremely toxic metal that can contaminate agricultural soils. To reduce the risk of Cd intake in food cereals, the development of cultivars with low grain Cd concentration (GCC) is an effective countermeasure. We analyzed quantitative trait loci (QTLs) for GCC in a doubled haploid (DH) common wheat (Triticum aestivum L.) population derived from 'Chugoku 165' (low GCC) × 'Chukei 10-22' (high GCC). We found novel loci for low GCC on the short arm of chromosome 4B and on the long arm of chromosome 6B. These QTLs accounted for 9.4%-25.4% (4B) and 9.0%-17.8% (6B) of the phenotypic variance in the DH population. An association analysis with 43 cultivars identified 3 loci at these QTLs: QCdc.4Bkita, QCdc.6B-kita1, and QCdc.6B-kita2. In contrast to durum wheat and barley, no QTL was detected on the chromosomes of homeologous group 5 for heavy metal P1B-type ATPase 3. These results will contribute to marker-assisted selection for low GCC in breeding of common wheat. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a highly toxic and non-essential element for plants, whereas phytochelatins and glutathione are lowmolecular- weight sulfur compounds that function as chelators and play important roles in detoxification. Cadmium exposure is known to induce the expression of sulfurassimilating enzymes and sulfate uptake by roots. However, the molecular mechanism underlying Cd-induced changes remains largely unknown. Accordingly, we analyzed the effects of Cd treatment on the uptake and translocation of sulfate and accumulation of thiols in Arabidopsis thaliana. Both wild type (WT) and null mutant (sel1-10 and sel1-18) plants of the sulfate transporter SULTR1;2 exhibited growth inhibition when treated with CdCl2. However, the mutant plants exhibited a lower growth rate and lower Cd accumulation. Cadmium treatment also upregulated the transcription of SULTR1;2 and sulfate uptake activity in WT plants, but not in mutant plants. In addition, the sulfate, phytochelatin and total sulfur contents were preferentially accumulated in the shoots of both WT and mutant plants treated with CdCl2, and sulfur K-edge XANES spectra suggested that sulfate was the main compound responsible for the increased sulfur content in the shoots of CdCl2-treated plants. Our results demonstrate that Cd-induced sulfate uptake depends on SULTR1;2 activity, and that CdCl2 treatment greatly shifts the distribution of sulfate to shoots, increases the sulfate concentration of xylem sap and upregulates the expression of SULTRs involved in root-toshoot sulfate transport. Therefore, we conclude that root-toshoot sulfate transport is stimulated by Cd and suggest that the uptake and translocation of sulfate in CdCl2-treated plants are enhanced by demand-driven regulatory networks. [ABSTRACT FROM AUTHOR]

Durum wheat (Triticum turgidum L.) cultivars can benefit from having some level of seed dormancy to help reduce seed damage and lower grain quality caused by preharvest sprouting (PHS) occurring during wet harvesting conditions. Previously, a single chromosome substitution line carrying chromosome 2B of wild emmer [Triticum turgidum L. subsp. dicoccoides (Körn. ex Asch. & Graebn.) Thell.] in the durum cultivar Langdon background was found to have higher levels of seed dormancy and PHS tolerance. In this study, a population of recombinant substitution lines was developed and used to construct a single nucleotide polymorphism (SNP)-based high-density genetic linkage map. Seed germination tests were used to evaluate seed dormancy levels. Multiple interval mapping analysis revealed four quantitative trait loci (QTL) regions affecting seed dormancy. Two regions containing major-effect QTL contributed by wild emmer were consistently expressed in four environments and explained 5.89 to 11.14% of the phenotypic variation. One QTL region was located near the centromere and the other on the long arm of chromosome 2B in Bayes credible intervals of 4 and 7 cM, respectively. Recombinant inbred lines (RILs) carrying both QTL had an average of 35% reduced rate of germination measured by weighted germination index compared with RILs carrying neither QTL. The two QTL regions identified in this study should be useful for improving PHS tolerance in wheat. Efforts to transfer the two QTL into elite durum cultivars are in progress to examine the effects of genetic background and environment on QTL expression and to evaluate the performance of other agronomic traits in the presence of the QTL. [ABSTRACT FROM AUTHOR]

Background Meningeal carcinomatosis and hypercoagulability associated with malignancy are typical late stage complications in cancer patients. The co-occurrence of meningeal carcinomatosis and cerebral infarction related to hypercoagulability associated with malignancy in an individual as the initial manifestation of malignancy has not been previously reported.Case presentation Herein, we report the case of an 80-year-old patient who presented with meningeal carcinomatosis and hypercoagulability related to malignancy as the initial manifestation of occult gastric cancer. The patient displayed consciousness disturbance, mild left facial paralysis, and bilateral positive Babinski's sign. Using brain magnetic resonance imaging, the patient was diagnosed as having acute multiple cerebral infarctions. Cerebrospinal fluid (CSF) cytology showed adenocarcinoma and upper gastrointestinal endoscopy disclosed scirrhous gastric cancer. The patient presented with headache, fever, and meningeal irritation with a subacute course. Tuberculous or fungal meningitis was initially suspected; however, cytological evidence of adenocarcinoma in the CSF led to the diagnosis of meningeal carcinomatosis. Conclusion The comorbidity of hypercoagulability associated with malignancy and meningeal carcinomatosis should be considered in a patient presenting with multiple cerebral infarctions, progressive disturbance of consciousness, fever, and meningeal irritation. [ABSTRACT FROM AUTHOR]

Chromosome compositions of seven lines, derived from hybrids between a wheat cultivar and the wheat- Thinopyrum intermedium addition line Z6, with barley yellow dwarf virus (BYDV) resistance, were determined by genomic in situ hybridization, cytogenetic and SSR assays. The results showed that line N522 was a disomic addition line, lines N420 and N439 were 2Ai-2(2B) chromosome substitution lines, lines N431 and N452 were 2Ai-2(2D) chromosome substitution lines, line N523 was a 2Ai-2S(2D) ditelosomic substitution line, and line N530 was a double ditelosomic line with the mitotic chromosome number of 2 n = 40 + 4t. One pair of telosomes in line N530 lacked several proximal SSR markers of chromosome 2AS, but possessed certain terminal markers, which were consistent with an acrocentric structure, and the other pair of chromosome arms were presumably 2Ai-2S telosomes with BYDV-resistance. These wheat- Th. intermedium lines provide useful genetic resources for developing alien chromosome translocation lines. [ABSTRACT FROM AUTHOR]

Expression profiles of a set of Cor/Lea genes were assessed during early stages of cold acclimation in seedlings of two wheat cultivars, which showed contrasting levels of freezing tolerance. These Cor/Lea family members consisted of three EST clones and 13 previously identified cDNA clones of wheat and rye. Northern blot analysis using RNA extracted from seedling leaves and roots showed that most of the genes exhibited a quite similar time-course of expression, although with different expression levels: They rapidly responded to low temperature and their transcript levels reached high plateaus within 3–5 days. The overall gene expression profiles were correlated with the time-dependent development and the level of freezing tolerance under low temperature in the two cultivars. Western blot analysis of protein accumulation further verified this observation. Abscissic acid response was proved for at least four genes. Light was stimulatory to most of the genes, and this positive light response associated with low temperature occurred not only in leaf-specific genes but also in leaf/root-expressed genes. Taken together, the present results suggest that the Cor/ Lea gene family represents a major group of downstream genes involved in the ABA-dependent and -independent signal pathways and that most of them are co-regulated in determining freezing tolerance in wheat seedlings. [ABSTRACT FROM AUTHOR]