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Rice blast is a destructive fungal disease affecting rice plants at various growth stages, significantly threatening global yield stability. Development of resistant rice cultivars stands as a practical means of disease control. Generally, association mapping with a diversity panel powerfully identifies new alleles controlling trait of interest. On the other hand, utilization of a breeding panel has its advantage that can be directly applied in a breeding program. In this study, we conducted a genome-wide association study (GWAS) for blast resistance using 296 commercial rice cultivars with low population structure but large phenotypic diversity. We attempt to answer the genetic basis behind rice blast resistance among early maturing cultivars by subdividing the population based on its Heading date 1 ( Hd1 ) functionality. Subpopulation-specific GWAS using the mixed linear model (MLM) based on blast nursery screening conducted in three years revealed a total of 26 significant signals, including three nucleotide-binding site leucine-rich repeat (NBS-LRR) genes ( Os06g0286500 , Os06g0286700 , and Os06g0287500 ) located at Piz locus on chromosome 6, and one at the Pi-ta locus ( Os12g0281300 ) on chromosome 12. Haplotype analysis revealed blast resistance associated with Piz locus was exclusively specific to Type 14 hd1 among japonica rice. Our findings provide valuable insights for breeding blast resistant rice and highlight the applicability of our elite cultivar panel to detect superior alleles associated with important agronomic traits., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Lee, Lee, Han, Ha, Lee, Kang, Jin, Suh, Jeung, Mo and Lee.)

Background: The exploitation of useful genes through interspecific and intersubspecific crosses has been an important strategy for the genetic improvement of rice. Postzygotic reproductive isolation routinely occurs to hinder the growth of pollen or embryo sacs during the reproductive development of the wide crosses., Result: In this study, we investigated the genetic relationship between the hybrid breakdown of the population and transferred resistance genes derived from wide crosses using a near-isogenic population composed of 225 lines. Five loci (qSS12, qSS8, qSS11, ePS6-1, and ePS6-2) associated with spikelet fertility (SF) were identified by QTL and epistatic analysis, and two out of five epistasis interactions were found between the three QTLs (qSS12, qSS8 and qSS11) and background marker loci (ePS6-1 and ePS6-2) on chromosome 6. The results of the QTL combinations suggested a genetic model that explains most of the interactions between spikelet fertility and the detected loci with positive or negative effects. Moreover, the major-effect QTLs, qSS12 and qSS8, which exhibited additive gene effects, were narrowed down to 82- and 200-kb regions on chromosomes 12 and 8, respectively. Of the 13 ORFs present in the target regions, Os12g0589400 and Os12g0589898 for qSS12 and OS8g0298700 for qSS8 induced significantly different expression levels of the candidate genes in rice at the young panicle stage., Conclusion: The results will be useful for obtaining a further understanding of the mechanism causing the hybrid breakdown of a wide cross and will provide new information for developing rice cultivars with wide compatibility., (© 2021. The Author(s).)

Background: Rice is one of the few cereals consumed as a whole grain, and therefore the appearance of the final milled product, both before and after cooking, strongly influences the consumer's perception of product quality. Matching consumer preference for rice grain quality is a key component of rice variety development programs, as the quality drives demand, which in turn drives variety adoption, market price, and profitability. The quality of cooked rice is normally evaluated indirectly, through measurement of key elements driving quality as well as more directly by sensory evaluation, but remains a complex trait conditioned by the genetic complexity of factors driving quality, changes wrought by environment, and the complexity of consumer preferences., Result: In this study, we evaluated 17 traits, including the taste value obtained by glossiness of cooked rice (TV), to explain rice eating quality by statistical methods and identified QTLs associated with TV. To explain the correlation among traits, exploratory factor analysis was performed for 2 years. The overall eating quality (OE) was correlated with TV and protein content loading at the same factor (PA1) in 2017, and there was a relationship between the OE (PA1) and the TV (PA2) in 2018 (PA1:PA2, r = 0.3). In QTL analysis using 174 RILs, three QTLs for TV derived from Wandoaengmi6 were detected on chromosomes 4, 6, and 9. The QTL qTV9 delimited within Id9007180 and 9,851,330 on chromosome 9 was detected in both years, explaining approximately 17% of the variation, on average. Through the use of fine mapping, qTV9 was delimited to an approximately 34-Kbp segment flanked by the DNA markers CTV9_9 and CTV9_13, and nine ORFs were listed in the target region as candidate genes associated with TV. In the evaluation of qTV9's effect on OE, the lines with qTV9 showed a significant increase in correlation coefficiency compared to the negative lines. These data will apply to functional analysis on the glossiness and the MAS breeding program to improve the eating quality of japonica as a donor line., Conclusion: In this paper we report a number of QTL associated with changes in glossiness of cooked rice, and these may have utility in the development of MAS in breeding programs with a specific focus on cooked grain quality.

The variable lymphocyte receptor B (VLRB) of jawless vertebrates has a similar function to the antibodies produced by jawed vertebrates, and has been considered as an alternative source to mammalian antibodies for use in biological research. We developed a modified yeast display vector system (pYD8) to display recombinant hagfish VLRB proteins on the extracellular surface of yeast for the isolation of antigen-specific VLRBs. After observing an up-regulation in the VLRB response in hagfish immunized with hemagglutinin 1 of avian influenza virus H9N2 subtype (H9N2-HA1), the antigen-specific VLRBs decorated on the yeast's surface were selected by quantitative library screening through magnetic-activated cell sorting (MACS) and fluorescent-activated cell sorting (FACS). We also demonstrated a strong specificity of the antigen-specific VLRBs, when expressed as a secreted protein using a mammalian expression system. Together, our findings suggest that the pYD8 vector system could be useful for screening antigen-specific hagfish VLRBs, and the specificity of secreted VLRB may have potential for a variety of biological applications., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The T cell receptor (TCR) is the binding site of antigen and is responsible for specifically activating the adaptive immune response. CD3, an essential component of the CD3-TCR complex, is known to be composed of γδ and ε chains in teleost. However, there are few monoclonal antibodies (mAb) available to identify these molecules on T cells, so we aimed to produce a mAb against CD3ε to improve our understanding of T cell immune response in olive flounder (Paralichthys olivaceus). CD3ε recombinant protein was expressed in yeast, the expression of which was confirmed by SDS-PAGE, MALDI-TOF/TOF MS and Western blot analysis. A CD3ε-specific mAb 4B2 was selected, the specificity of which was examined by confocal microscopy, flow cytometry and RT-PCR, and the mAb was subsequently used to examine the CD3ε lymphocyte population in several different immune organs, with relatively high percentages of these cells seen in trunk-kidney and spleen, while lower percentages were seen in the liver and peripheral blood of olive flounder. During a viral hemorrhagic septicemia virus (VHSV) infection in olive flounder, the number of CD3ε lymphocytes was seen to gradually increase in the liver, spleen and trunk-kidney of infected fish until 7 days post infection (dpi). In peripheral blood, on the other hand, the increase in CD3ε lymphocyte numbers peaked by 3 dpi. These results suggest that CD3ε lymphocytes might be involved in the immune response against VHSV., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Brown planthopper (BPH) is a phloem sap-sucking insect pest of rice which causes severe yield loss. We cloned the BPH18 gene from the BPH-resistant introgression line derived from the wild rice species Oryza australiensis. Map-based cloning and complementation test revealed that the BPH18 encodes CC-NBS-NBS-LRR protein. BPH18 has two NBS domains, unlike the typical NBS-LRR proteins. The BPH18 promoter::GUS transgenic plants exhibited strong GUS expression in the vascular bundles of the leaf sheath, especially in phloem cells where the BPH attacks. The BPH18 proteins were widely localized to the endo-membranes in a cell, including the endoplasmic reticulum, Golgi apparatus, trans-Golgi network, and prevacuolar compartments, suggesting that BPH18 may recognize the BPH invasion at endo-membranes in phloem cells. Whole genome sequencing of the near-isogenic lines (NILs), NIL-BPH18 and NIL-BPH26, revealed that BPH18 located at the same locus of BPH26. However, these two genes have remarkable sequence differences and the independent NILs showed differential BPH resistance with different expression patterns of plant defense-related genes, indicating that BPH18 and BPH26 are functionally different alleles. These findings would facilitate elucidation of the molecular mechanism of BPH resistance and the identified novel alleles to fast track breeding BPH resistant rice cultivars.

Key Message: A new bacterial blight resistance gene has been identified through fine-mapping, which confers high levels of resistance to all Korean Xanthomonas oryzae pv. oryzae (Xoo) races, including the new Xoo race K3a. Rice bacterial leaf blight (BB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is a serious constraint to rice production in Asia and Africa. The japonica advanced backcross breeding lines derived from the indica line IR65482-7-216-1-2 in the background of cultivar Junam are resistant to all Korean BB races, including K3a. To identify the gene(s) involved in resistance to Korean Xoo races, the association of genotypic and phenotypic variations was examined in two F2 populations derived from the crosses between 11325 (IR83261-3-7-23-6-2-1-1-2-1-2)/Anmi and 11325/Ilpum. The segregation ratios of F2 individuals from the crosses of 11325/Anmi and 11325/Ilpum were 578 resistant:209 susceptible and 555 resistant:241 susceptible, respectively, which is consistent with the expected allelic frequency of a 3:1 ratio. Genetic analysis using graphical mapping indicated that resistance (R) was controlled by a new resistance gene linked with the flanking markers RM27320 and ID55.WA18-5 within an approximately 80-kb region between 28.14 and 28.22 Mbp on chromosome 11. The eight candidate genes functionally predicted were included in the target region. Examination of the candidate genes by RT-PCR analysis only corroborated with the significant difference in transcript levels of the WAK3 gene in the presence or absence of pathogen infection. Allelism tests performed with other known BB R-genes revealed that the allele was distinct from others having a similar chromosomal location.

Cold stress at the seedling stage is a major threat to rice production. Cold tolerance is controlled by complex genetic factors. We used an F7 recombinant inbred line (RIL) population of 123 individuals derived from a cross of the cold-tolerant japonica cultivar Jinbu and the cold-susceptible indica cultivar BR29 for QTL mapping. Phenotypic evaluation of the parents and RILs in an 18/8 °C (day/night) cold stress regime revealed continuous variation for cold tolerance. Six QTLs including two on chromosome 1 and one each on chromosomes 2, 4, 10, and 11 for seedling cold tolerance were identified with phenotypic variation (R(2)) ranging from 6.1 to 16.5 %. The QTL combinations (qSCT1 and qSCT11) were detected in all stable cold-tolerant RIL groups, which explained the critical threshold of 27.1 % for the R(2) value determining cold tolerance at the seedling stage. Two QTLs (qSCT1 and qSCT11) on chromosomes 1 and 11, respectively, were fine mapped. The markers In1-c3, derived from the open reading frame (ORF) LOC_Os01g69910 encoding calmodulin-binding transcription activator (CAMTA), and In11-d1, derived from ORF LOC_Os11g37720 (Duf6 gene), co-segregated with seedling cold tolerance. The result may provide useful information on seedling cold tolerance mechanism and provide DNA markers for a marker-assisted breeding program to improve seedling cold tolerance in indica rice varieties.

Objectives: To investigate the clinicopathologic and endoscopic features of precursor lesions associated with traditional serrated adenomas (TSAs)., Methods: Mutation studies for BRAF, KRAS, PIK3CA, and EGFR and immunohistochemical staining for Ki-67 were performed on 107 TSAs from 104 patients., Results: Nondysplastic hyperplastic polyp (HP) or sessile serrated adenoma/polyp (SSA/P) precursor lesions were found in 56 (52.3%) TSAs, among which 32 (57.1%) cases showed a flat-elevated lesion with a type II pit pattern during endoscopy. TSAs with an SSA/P precursor lesion were usually found in the proximal colon, while TSAs with an HP or with no precursor lesion were mainly located in the distal colon and rectum (P < .001). TSAs with a precursor lesion showed a lower frequency of conventional epithelial dysplasia and KRAS mutation as well as a higher frequency of BRAF mutation compared with those with no precursor lesion (P = .002, P < .001, and P < .001, respectively)., Conclusions: A significant proportion of HP or SSA/P precursor lesions accompanied by TSAs can be detected by endoscopy based on both their flat-elevated growth and type II pit patterns. The heterogeneity of TSAs in terms of clinicopathologic and molecular features correlated with the status or type of precursor lesions.

Background/aims: There have been no definite indications for additional surgical resection after endoscopic submucosal dissection (ESD) of submucosal invasive colorectal cancer (SICC). The aims of this study were to evaluate the feasibility of ESD for nonpedunculated SICC and to determine the need for subsequent surgery after ESD., Patients and Methods: A total of 150 patients with nonpedunculated SICC in resected specimens after ESD were analyzed. Among them, 75 patients underwent subsequent surgery after ESD. Clinical outcomes of ESD and histopathological risk factors for lymph node (LN) metastasis were evaluated., Results: The en-bloc resection and complete resection (R0) rates of ESD were 98% (147/150) and 95.3% (143/150), respectively. None of the patients had delayed bleeding after ESD. Perforations occurred in seven patients (4.7%), which were successfully treated by endoscopic clipping. After subsequent surgery for 75 patients, LN metastases were found in 10 cases (13.3%). The incidence of LN metastasis was significantly higher in tumors featuring submucosal invasion of at least 1500 μm, lymphovascular invasion, and tumor budding. Multivariate analysis showed that lymphovascular invasion (P=0.034) and tumor budding (P=0.015) were significantly associated with LN metastasis. Among the 150 patients, no local recurrence or distant metastasis was detected, except one patient with risk factors and who refused subsequent surgery, during the overall median follow-up of 34 months (range, 5-63 months)., Conclusion: ESD is feasible and may be considered as an alternative treatment option for carefully selected cases of nonpedunculated SICC, provided that the appropriate histopathological curative criteria are fulfilled in completely resectable ESD specimens.

Background: Snare polypectomy of a giant pedunculated colorectal polyp is sometimes technically demanding, and, therefore, piecemeal resection is inevitable, despite the relative risk of invasive cancer and postpolypectomy bleeding., Objective: The aim of this study was to evaluate the efficacy and safety of endoscopic submucosal dissection in comparison with conventional snare polypectomy for giant pedunculated polyps, Design and Settings: We retrospectively reviewed the clinical outcomes and complications of endoscopic polypectomy for giant pedunculated polyps from October 2006 to November 2011., Patients: All the patients who underwent endoscopic submucosal dissection (n = 23) or snare polypectomy (n = 20) for pedunculated polyps ≥ 3 cm were enrolled consecutively. In the case of a giant pedunculated polyp with 1) poor visualization of the stalk, 2) technical difficulties in snare positioning for en bloc resection, or 3) need for trimming of the head, we did not attempt piecemeal snare polypectomy, and we performed endoscopic submucosal dissection instead. (These were arbitrarily defined as "difficult" giant pedunculated polyps.), Main Outcome Measures: Data on the patient's demography, endoscopic and histopathologic findings, clinical outcomes, and complications were analyzed., Results: Among the 43 giant pedunculated polyps, 23 polyps were defined as "difficult" polyps and were removed with endoscopic submucosal dissection. Subpedunculated (stalk <1 cm) type was more common in the "difficult" polyp group (p = 0.01). The overall incidence of cancer was 18.6% (8/43). En bloc resection rates were 100% (23/23) in the endoscopic submucosal dissection group and 90% (18/20) in the snare polypectomy group. The procedure times of snare polypectomy and endoscopic submucosal dissection group did not differ significantly (41.7 ± 13.7 minutes vs 44.9 ± 35.6 minutes, p = 0.70). Postpolypectomy bleeding was noted in 1 case (4.3%) in the endoscopic submucosal dissection group and in 3 cases (15%) in the snare polypectomy group., Conclusions: Endoscopic submucosal dissection, as well as the snare polypectomy for giant pedunculated polyps, appeared to be effective without major complications and can be an alternative option to achieve en bloc resection, particularly for difficult cases, such as giant subpedunculated polyps.

Background: The development of resistant cultivars has been the most effective and economical strategy to control bacterial leaf blight (BB) disease of rice caused by Xanthomonas oryzae pv. oryzae (Xoo). Molecular markers have made it possible to identify and pyramid valuable genes of agronomic importance in resistance rice breeding. In this study, three resistance genes (Xa4 + xa5 + Xa21) were transferred from an indica donor (IRBB57), using a marker-assisted backcrossing (MAB) breeding strategy, into a BB-susceptible elite japonica rice cultivar, Mangeumbyeo, which is high yielding with good grain quality., Results: Our analysis led to the development of three elite advanced backcross breeding lines (ABL) with three resistance genes by foreground and phenotypic selection in a japonica genetic background without linkage drag. The background genome recovery of the ABL expressed more than 92.1% using genome-wide SSR marker analysis. The pathogenicity assays of three resistance-gene-derived ABL were conducted under glasshouse conditions with the 18 isolates of Xoo prevalent in Korea. The ABL exhibited very small lesion lengths, indicating a hypersensitive reaction to all 18 isolates of Xoo, with agronomic and grain quality traits similar to those of the recurrent parent. Pyramiding the resistance genes Xa4, xa5 and Xa21 provided a higher resistance to Xoo than the introduction of the individual resistance genes. Additionally, the combination of two dominant and one recessive BB resistance gene did not express any negative effect on agronomic traits in the ABL., Conclusions: The strategy of simultaneous foreground and phenotypic selection to introduce multiple R genes is very useful to reduce the cost and the time required for the isolation of desirable recombinants with target resistance genes in rice. The resistance-gene-derived ABL have practical breeding value without a yield penalty by providing broad-spectrum resistance against most of the existing isolates of BB in South Korea and will have a high impact on the yield stability and sustainability of rice productivity.

Inflammatory pseudopolyps are formed in the regenerative and healing phases of ulcerated epithelium. Giant pseudopolyposis of the colon (pseudopolyp larger than 1.5 cm in size) is a very rare complication of inflammatory bowel disease and it may lead to colonic intussusception or luminal obstruction, but the more important clinical significance is that it can be endoscopically confused with a malignancy, although it is generally regarded as having no malignant potential. It has been reported that giant pseudopolyposis of the colon rarely regresses with medical management alone and this sometimes require surgical or endoscopic resection. This report illustrates 2 unusual cases of giant pseudopolyps associated with Crohn's disease and ulcerative colitis, and these giant pseudopolyps were initially confused with villous adenoma or adenocarcinoma, but they showed regression after adequate medical therapy., (Copyright © 2011 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved.)

Improved eating quality is a major breeding target in japonica rice due to market demand. In this study, we performed genetic analysis to identify quantitative trait loci (QTLs) that control rice eating quality traits using 192 recombinant inbred lines (RILs) derived from a cross between two japonica cultivars, 'Suweon365' and 'Chucheongbyeo'. We evaluated the stickiness (ST) and overall evaluation (OE) of cooked rice using a sensory test, the glossiness of cooked rice (GCR) using a Toyo-taste meter, and measured the amylose content (AC), protein content (PC), alkali digestion value (ADV), and days to heading (DH) of the RILs in the years 2006 and 2007. Our analysis revealed 21 QTLs on chromosomes 1, 4, 6, 7, 8, and 11. QTLs on chromosomes 6, 7, and 8 were detected for three traits related to eating quality in both years. QTLs for ST and OE were identified by a sensory test in the same region of the QTLs for AC, PC, ADV, GCR and DH on chromosome 8. QTL effects on the GCR were verified using QTL-NILs (near-isogenic lines) of BC(3)F(4-6) in the Suweon365 background, a low eating quality variety, and some BC(1)F(3) lines. Chucheongbyeo alleles at QTLs on chromosomes 7 and 8 increased the GCR in the NILs and backcrossed lines. The QTLs identified by our analysis will be applicable to future marker-assisted selection (MAS) strategies for improving the eating quality of japonica rice.

Aim: To evaluate the efficacy and acceptability of magnesium citrate and a single dose of oral sodium phosphate (45 mL) solution for morning colonoscopy bowel preparation., Methods: A total of 159 patients were randomly assigned to receive two split doses of 90 mg of sodium phosphate (Group I, n = 79) or magnesium citrate (250 mL, the day before the procedure) followed by 45 mL of sodium phosphate (the day of procedure, Group II, n = 80). The quality of bowel cleansing and the acceptability of each regimen were compared, including the satisfaction, taste, willing to repeat and adverse effects of each regimen., Results: The quality of bowel cleansing of Group II was as good as that of Group I (An Aronchick scale score of good or excellent: 70.9% vs 81.0%, respectively, P = 0.34; the Ottawa system score: 4.4 ± 2.6 vs 3.8 ± 3.0, respectively, P = 0.76). There was no statistically significant difference between both groups with regard to acceptability, including the satisfaction, taste and willingness to repeat the regimen. A significantly greater number of older patients (over 65 years old) in Group II graded the overall satisfaction as satisfactory (48.1% vs 78.1%, respectively; Group I vs Group II, P = 0.01). There were no significant adverse reactions., Conclusion: Magnesium citrate and a single dose of sodium phosphate was as effective and tolerable as the conventional sodium phosphate regimen and is a satisfactory option.

The immunosuppressant azathioprine (AZA) is widely used in the treatment of inflammatory bowel disease (IBD) for both inducing and maintaining remission. However, the adverse effects of AZA can often necessitate a dose reduction or discontinuation. Bone marrow suppression is one of the most serious complications with AZA treatment. On the other hand, some reports have suggested that neutropenia during AZA therapy reduced the relapse rates of IBD patients, and there have been some cases where eradication of the sensitized leukocytes by leukapheresis or bone marrow transplantation improved the IBD, which may explain the relevant role of neutropenia in controlling disease activity. This report describes the case of a 22-year-old male patient who had Crohn's colitis and complicated perianal fistulas that required immunosuppression; he achieved endoscopically determined remission and showed accelerated mucosal healing as well as clinical remission following the AZA-induced pancytopenia.

Background: For asymptomatic individuals aged 40-49 years, screening for colorectal cancer is recommended only if individuals are at an increased risk. A family history of colon cancer (FHCRC) is considered to increase risk, however, whether family history of stomach cancer (FHSC) increases the risk of adenoma is not well known. We aimed to see whether FHSC increases the risk in asymptomatic individuals aged 40-49 years in Korea., Methods: Among asymptomatic individual aged 40-49 years who underwent colonoscopy screening, risk of adenoma was assessed according to FHCRC or FHSC., Results: Of 3,160 individuals, male comprised 1,602 individuals (50.7%). FHCRC and FHSC was noticed in 163 (5.2%) and 227 (7.0%) individuals, respectively. Prevalence of adenoma was 31.9 %, 28.8%, and 22.3% for individuals with FHCRC, individuals with FHSC, and individuals without family history of cancer, respectively. FHSC was an independent risk factor for adenoma (odds ratio, 1.38; 95% confidence interval, 1.02-1.87, P = 0.039) in asymptomatic individuals aged 40-49 years. Compared with individuals with FHCRC, individuals with FHSC showed no difference in risk for adenoma (P = 0.347)., Conclusions: As with individuals with FHCRC, individuals with FHSC might need to be considered as an individual with increased risk for adenoma. Therefore, earlier screening might be needed for asymptomatic individuals aged 40-49 years with FHSC in Korea.

Low temperature or cold stress is one of the major constraints of rice production and productivity in temperate rice-growing countries and high-altitude areas in the tropics. Even though low temperature affects the rice plant in all stages of growth, the percent seed set is damaged severely by cold and this reduces the yield potential of cultivars significantly. In this study, a new source of cold-tolerant line, IR66160-121-4-4-2, was used as a donor parent with a cold-sensitive cultivar, Geumobyeo, to produce 153 F(8) recombinant inbred lines (RILs) for quantitative trait locus (QTL) analysis. QTL analysis with 175 polymorphic simple sequence repeat (SSR) markers and composite interval mapping identified three main-effect QTLs (qPSST-3, qPSST-7, and qPSST-9) on chromosomes 3, 7, and 9. The SSR markers RM569, RM1377, and RM24545 were linked to the identified QTLs for cold tolerance with respect to percent seed set using cold-water (18-19 degrees C) irrigation in the field and controlled air temperature (17 degrees C) in the greenhouse. The total phenotypic variation for cold tolerance contributed by the three QTLs was 27.4%. RILs with high percent seed set under cold stress were validated with linked DNA markers and by haplotype analysis that revealed the contribution of progenitor genomes from the tropical japonica cultivar Jimbrug (Javanica) and temperate japonica cultivar Shen-Nung89-366. Three QTLs contributed by the cold-tolerant parent were identified which showed additive effect on percent seed set under cold treatment. This study demonstrated the utility of a new phenotyping method as well as the identification of SSR markers associated with QTLs for selection of cold-tolerant genotypes to improve temperate rice production.

Background: Self-expandable metallic stent (SEMS) for malignant colorectal obstruction is widely used in palliative treatment and as an alternative to surgery. The aims of this study are to evaluate the effectiveness of stent placement for palliative treatment and to identify the predictive factors associated with stent occlusion., Methods: A retrospective analysis was performed in 55 patients who had undergone placement of an uncovered SEMS from February 2004 to April 2007 for palliative treatment of malignant colorectal obstruction with metastatic or locally advanced cancer that was surgically unresectable. We analyzed the technical and clinical outcomes of stent placement, complications related to the procedure, stent patency rate, and predictive factors associated with stent occlusion., Results: The causes of colorectal obstruction before stent placement were primary colorectal cancer in 42 patients and noncolorectal extrinsic cancer in 13 patients. The initial technical success rate was 98.2%, and the clinical success rate was 94.4%. Complications occurred in 17 patients (30.9%). These included stent occlusion (n = 8), migration (n = 6), bowel perforation (n = 1), stent distortion (n = 1), and fistula formation (n = 1). The mean and median stent patency periods were 184 days [95% confidence interval (CI), 137-230 days] and 141 days (95% CI, 69-213 days), respectively. The degree of expansion 48 h after stent placement was significantly better in the nonocclusion group than in the stent occlusion group. In the multivariate Cox proportional hazard model, insufficient stent expansion (<70%) 48 h after stent placement was significantly associated with an increase in stent occlusion during the follow-up period (odds ratio, 12.55; p = 0.002)., Conclusions: Uncovered SEMS placement is an effective palliative treatment for malignant colorectal obstruction. The degree of stent expansion 48 h after stent placement is significantly associated with the maintenance of stent patency and is a predictive factor for stent occlusion.

Rice blast, caused by the fungus Magnaporthe oryzae, is one of the most devastating diseases of rice. To understand the molecular basis of Pi5-mediated resistance to M. oryzae, we cloned the resistance (R) gene at this locus using a map-based cloning strategy. Genetic and phenotypic analyses of 2014 F2 progeny from a mapping population derived from a cross between IR50, a susceptible rice cultivar, and the RIL260 line carrying Pi5 enabled us to narrow down the Pi5 locus to a 130-kb interval. Sequence analysis of this genomic region identified two candidate genes, Pi5-1 and Pi5-2, which encode proteins carrying three motifs characteristic of R genes: an N-terminal coiled-coil (CC) motif, a nucleotide-binding (NB) domain, and a leucine-rich repeat (LRR) motif. In genetic transformation experiments of a susceptible rice cultivar, neither the Pi5-1 nor the Pi5-2 gene was found to confer resistance to M. oryzae. In contrast, transgenic rice plants expressing both of these genes, generated by crossing transgenic lines carrying each gene individually, conferred Pi5-mediated resistance to M. oryzae. Gene expression analysis revealed that Pi5-1 transcripts accumulate after pathogen challenge, whereas the Pi5-2 gene is constitutively expressed. These results indicate that the presence of these two genes is required for rice Pi5-mediated resistance to M. oryzae.

Rice blast severely reduces production in both irrigated and water-stressed upland ecosystems of tropical and temperate countries. Nearly 50 blast resistance genes have been identified and some of those are incorporated into several rice cultivars. However, most of the resistance genes break down in a few years because of their race specificity and the rapid change in pathogenicity of the blast fungus (Magnaporthe grisea). The objective of this study was to analyze advanced backcross breeding lines (ABL) possessing the gene Pi40 for durable rice blast resistance. In all, 4 resistant genotypes, 4 japonica cultivars, and 10 monogenic differential rice genotypes with some known resistance genes were bioassayed in the greenhouse using seven sequential plantings and 29 virulent M. grisea isolates of Korea. The genotypes with the Pi40 gene had <3% diseased leaf area, which was significantly below the disease threshold level of 40% considered for durable blast resistance. Moreover, the genotypes with the Pi40 gene expressed compatibility with only two to three virulent M. grisea isolates supporting durability of resistance, in contrast to susceptible cultivars with >50% diseased leaf area and 10 compatible isolates. Of the 10 known resistance genes tested, Piz-t, Piz-5, and Pi9 showed differential reactions to the pathogen isolates in seven plantings. Genotyping of the ABL with 260 simple sequence repeat (SSR) markers revealed rapid conversion toward recurrent parent genotypes with fewer donor chromosomal segments (5.3 to 14.5%). Our study based on a sequential testing and background selection of breeding lines with the resistance gene Pi40 provided valuable information for durable blast resistance breeding in rice.

Thirteen near-isogenic lines (NILs) of japonica rice were developed via a backcross method using the recurrent parent Chucheong, which is of good eating quality but is susceptible to Magnaporthe grisea, and three blast resistant japonica donors, Seolak, Daeseong and Bongkwang. The agro-morphological traits of these NILs, such as heading date, culm length, and panicle length, were similar to those of Chucheong. In a genome-wide scan using 158 SSR markers, chromosome segments of Chucheong were identified in most polymorphic regions of the 13 NIL plants, and only a few chromosome segments were found to have been substituted by donor alleles. The genetic similarities of the 13 NILs to the recurrent parent Chucheong averaged 0.961, with a range of 0.932-0.984. Analysis of 13 major blast resistance (R) genes in these lines using specific DNA markers showed that each NIL appeared to contain some combination of the four R genes, Pib, Pii, Pik-m and Pita-2, with the first three genes being present in each line. Screening of nine M. grisea isolates revealed that one NIL M7 was resistant to all nine isolates; the remaining NILs were each resistant to between three and seven isolates, except for NIL M106, which was resistant to only two isolates. In a blast nursery experiment, all the NILs proved to be more resistant than Chucheong. These newly developed NILs have potential as commercial rice varieties because of their increased resistance to M. grisea combined with the desirable agronomic traits of Chucheong. They also provide material for studying the genetic basis of blast resistance.

A high-resolution physical map targeting a cluster of yield-related QTLs on the long arm of rice chromosome 9 has been constructed across a 37.4 kb region containing seven predicted genes. Using a series of BC3F4 nearly isogenic lines (NILs) derived from a cross between the Korean japonica cultivar Hwaseongbyeo and Oryza rufipogon (IRGC 105491), a total of seven QTLs for 1,000-grain weight, spikelets per panicle, grains per panicle, panicle length, spikelet density, heading date and plant height were identified in the cluster (P

Background/aims: Although previous reports suggested that pepsinogen (PG) I/II ratio was the index of gastric atrophy, PG I/II ratio was also related to other factors such as Helicobacter pylori (H. pylori) infection, various gastrointestinal diseases, and aging. The aim of this study was to evaluate the relationship between serum PG I/II ratio and age or upper gastro-intestinal diseases according to H. pylori infection status., Methods: A total of 529 individuals (307 male; mean age, 57.2 years) were divided into 4 groups (94 gastric ulcers, 35 duodenal ulcers, 105 reflux esophagitis, and 295 atrophic gastritis) according to endoscopic diagnosis. H. pylori infection was determined by H. pylori IgG antibody (ELISA) and PG was measured by latex immunoassay., Results: H. pylori infected patients showed markedly increased serum PG II levels (24.0+/-14.7 ng/mL vs. 13.8+/-16.6 ng/mL, p0.001) and low PG I/II ratio (3.9+/-2.0 vs. 6.0+/-2.5, p0.001) than non-infected subjects. In H. pylori infected patients, mean PG I/II ratios in the gastric ulcer and atrophic gastritis group were significantly lower than those of the duodenal ulcer and reflux esophagitis group (p0.001, ANOVA, Turkey's multiples comparison test). The mean ratio of open type atrophic gastritis was lower than that of close type atrophic gastritis (3.0+/-1.4 vs. 3.8+/-1.7, p0.005). PG I/II ratio gradually decreased with age in H. pylori-infected patients with atrophic gastritis (R(2)=0.9, p=0.005, linear regression analysis)., Conclusion: Serum PG I/II ratio reflects H. pylori infection and gastric atrophy. In the presence of H. pylori infection, gastric atrophy progresses with age.

A quantitative trait locus (QTL) for grain weight (GW) was detected near SSR marker RM210 on chromosome 8 in backcross populations derived from a cross between the Korean japonica cultivar Hwaseongbyeo and Oryza rufipogon (IRGC 105491). The O. rufipogon allele increased GW in the Hwaseongbyeo background despite the fact that O. rufipogon was the small-seeded parent. Using sister BC(3)F(3) near-isogenic lines (NILs), gw8.1 was validated and mapped to a 6.1 cM region in the interval between RM42 and RM210 (P < or = 0.0001). Substitution mapping with eight BC(3)F(4) sub-NILs further narrowed the interval containing gw8.1 to about 306.4 kb between markers RM23201.CNR151 and RM30000.CNR99. A yield trial using homozygous BC(3)F(4) sister sub-NILs and the Hwaseongbyeo recurrent parent indicated that the NIL carrying an O. rufipogon chromosome segment across the entire gw8.1 target region out-yielded its sister NIL (containing Hwaseongbyeo chromosome in the RM42-RM210 interval) by 9% (P=0.029). The higher-yielding NIL produced 19.3% more grain than the Hwaseongbyeo recurrent parent (P=0.018). Analysis of a BC(3)F(4) NIL indicated that the variation for GW is associated with variation in grain shape, specifically grain length. The locus, gw8.1 is of particular interest because of its independence from undesirable height and grain quality traits. SSR markers tightly linked to the GW QTL will facilitate cloning of the gene underlying this QTL as well as marker-assisted selection for variation in GW in an applied breeding program.

Introgression has been achieved from wild species Oryza grandiglumis (2n = 48, CCDD, Acc. No. 101154) into O. sativa subsp. japonica cv. Hwaseongbyeo as a recurrent parent. An advanced introgression (backcross) line, HG101, produced from a single plant from BC5F3 families resembled Hwaseongbyeo, but it showed differences from Hwaseongbyeo in several traits, including days to heading and culm length. To detect the introgressions, 450 microsatellite markers of known chromosomal position were used for the parental survey. Of the 450 markers, 51 (11.3%) detected O. grandiglumis segments in HG101. To characterize the effects of alien genes introgressed into HG101, an F(2:3) population (150 families) from the cross Hwaseongbyeo/HG101 was developed and evaluated for 13 agronomic traits. Several lines outperformed Hwaseongbyeo in several traits, including days to heading. Genotypes were determined for 150 F2 plants using simple sequence repeat markers. Qualitative trait locus (QTL) analysis was carried out to determine the relationship between marker genotype and the traits evaluated. A total of 39 QTL and 1 gene conferring resistance to blast isolate were identified using single-point analysis. Phenotypic variation associated with each QTL ranged from 4.2 to 30.5%. For 18 (46.2%) of the QTL identified in this study, the O. grandiglumis-derived alleles contributed a desirable agronomic effect despite the overall undesirable characteristics of the wild phenotype. Favorable wild alleles were detected for days to heading, spikelets per panicle, and grain shape traits. Grain shape QTL for grain weight, thickness, and width identified in the F(2:3) lines were further confirmed based on the F4 progeny test. The confirmed locus, tgw2 for grain weight is of particular interest because of its independence from undesirable height and maturity. Several QTL controlling amylose content and grain traits have not been detected in the previous QTL studies between Oryza cultivars, indicating potentially novel alleles from O. grandiglumis. The QTL detected in this study could be a rich source of natural genetic variation underlying the evolution and breeding of rice.