Transcriptome-guided resolution of tumor microenvironment interactions in pheochromocytoma and paraganglioma subtypes.

BACKGROUND: Pheochromocytomas and paragangliomas (PCPG) are rare catecholamine-secreting endocrine tumors deriving from chromaffin cells of the embryonic neural crest. Although distinct molecular PCPG subtypes have been elucidated, certain characteristics of these tumors have yet to be fully examined, namely the tumor microenvironment (TME). To further understand tumor-stromal interactions in PCPG subtypes, the present study deconvoluted bulk tumor gene expression to examine ligand-receptor interactions. METHODS: RNA-sequencing data primary solid PCPG tumors were derived from The Cancer Genome Atlas (TCGA). Tumor purity was estimated using two robust algorithms. The tumor purity estimates and bulk tumor expression values allowed for non-negative linear regression to predict the average expression of each gene in the stromal and tumor compartments for each PCPG molecular subtype. The predicted expression values were then used in conjunction with a previously curated ligand-receptor database and scoring system to evaluate top ligand-receptor interactions. RESULTS: Across all PCPG subtypes compared to normal samples, tumor-to-tumor signaling between bone morphogenic proteins 7 (BMP7) and 15 (BMP15) and cognate receptors ACVR2B and BMPR1B was increased. In addition, tumor-to-stroma signaling was enriched for interactions between predicted tumor-originating delta-like ligand 3 (DLL3) and predicted stromal NOTCH receptors. Stroma-to-tumor signaling was enriched for interactions between ephrins A1 and A4 with ephrin receptors EphA5, EphA7, and EphA8. Pseudohypoxia subtype tumors displayed increased predicted stromal expression of genes related to immune-exhausted T-cell response, including those for inhibitory receptors HAVCR2 and CTLA4. CONCLUSION: The current exploratory study predicted stromal and tumor through compartmental deconvolution and yielded previously unrecognized interactions and putative biomarkers in PCPG.

Mechanism of lncRNA DUXAP8 in promoting proliferation of bladder cancer cells by regulating PTEN.

OBJECTIVE: To evaluate the lncRNA DUXAP8 expression in bladder cancer and its mechanism. PATIENTS AND METHODS: Clinical specimens were analyzed. The expression of lncRNA in bladder cancer and adjacent tissues was detected using qRT-PCR. The χ2-test analysis was used to analyze the relationship between lncRNA DUXAP8 expression and clinicopathological information in patients with bladder cancer. The tumor cell activity and cell proliferation were measured by cell counting kit-8 (CCK8) and colony formation assay. We utilized polymerase chain reaction (PCR) to access PTEN expression in bladder cancer and adjacent tissues. Pearson correlation analysis was utilized for evaluating the relationship between PTEN and lncRNA DUXAP8. Western blot was used for detecting protein expression. RESULTS: LncRNA DUXAP8 expression was higher in bladder cancer tissues; it was in a positive correlation with the TNM stage and tumor size, but negatively correlated with the total survival time. Knockdown of DUXAP8 decreased cell viability and cellular proliferation. Lower expression of PTEN gene was found in bladder cancer compared with that in adjacent tissues. Pearson correlation analysis showed that PTEN was negatively correlated with DUXAP8; knockdown of DUAP8 increased the expression of PTEN. Overexpressing DUAP8 increased protein level of PTEN, but decreased cell viability. CONCLUSIONS: Our results pointed out that lncRNA DUXAP8 was overexpressed in bladder cancer tissues, which can promote the progression of bladder cancer through inhibiting PTEN.

Asthma and COPD overlap syndrome is associated with increased risk of hospitalisation.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is associated with poor prognosis and a high health care burden. The incidence of asthma and COPD overlap syndrome is increasing, and contributes to a high financial burden and poor prognosis. OBJECTIVE: To investigate clinical features of the overlap syndrome among Asian patients and to analyse its impact on hospitalisation due to respiratory problems or death compared to COPD alone. DESIGN: We performed a retrospective cohort analysis of 2933 COPD patients presenting at the Asan Medical Center from 1 January 2000 to 31 December 2009. Kaplan-Meier and Cox proportional hazard models were used to analyse the significance of clinical parameters, including age, sex, smoking history, body mass index (BMI), severity of airflow limitation, airway obstruction reversibility and overlap syndrome with hospitalisation due to respiratory problems or death. RESULTS: Overlap syndrome patients were older, included smaller proportions of males and of smokers and had lower forced expiratory volume in 1 s (FEV1) (% predicted). Shorter hospitalisation-free and survival periods were noted among overlap syndrome patients. Overlap syndrome was significantly associated with risk of hospitalisation due to respiratory problems after adjusting for age, smoking history, BMI, FEV1 (% predicted) and changes in FEV1 (P < 0.001). CONCLUSION: Asthma and COPD overlap syndrome is associated with a higher risk of hospitalisation due to respiratory problems than COPD alone.

Sub-nanosecond time-resolved near-field scanning magneto-optical microscope.

We report on the development of a new magnetic microscope, time-resolved near-field scanning magneto-optical microscope, which combines a near-field scanning optical microscope and magneto-optical contrast. By taking advantage of the high temporal resolution of time-resolved Kerr microscope and the sub-wavelength spatial resolution of a near-field microscope, we achieved a temporal resolution of ∼50 ps and a spatial resolution of <100 nm. In order to demonstrate the spatiotemporal magnetic imaging capability of this microscope, the magnetic field pulse induced gyrotropic vortex dynamics occurring in 1 µm diameter, 20 nm thick CoFeB circular disks has been investigated. The microscope provides sub-wavelength resolution magnetic images of the gyrotropic motion of the vortex core at a resonance frequency of ∼240 MHz.

New polymorphic microsatellite markers for the Korean manila clam (Ruditapes philippinarum) and their application to wild populations.

Manila clam (Ruditapes philippinarum) is a valuable and intensively exploited shellfish species in Korea. Despite its importance, information on its genetic background is scarce. For the genetic characterization of R. philippinarum, expressed sequence tag-derived microsatellite markers were developed using next-generation sequencing. A total of 5879 tandem repeats containing di- to hexanucleotide repeat motifs were obtained from 236,746 reads (mean = 413 bp). Of the 62 loci screened, 24 (38.7%) were successfully amplified, and 10 were polymorphic in 144 individuals from 2 manila clam populations (Incheon and Geoje, Korea). The number of alleles ranged from 2 to 17 in the Incheon population and from 3 to 13 in the Geoje population (overall AR = 7.21). The mean observed and expected heterozygosities were estimated to be 0.402 and 0.555, respectively. Hence, there is less genetic variability in the Geoje population than in the Incheon population, although no significant reductions of genetic diversity were found between the populations (P > 0.05). However, significant genetic differentiation was detected between the populations (FST = 0.064, P < 0.001). Significant deviations from Hardy-Weinberg equilibrium and high inbreeding coefficients (mean FIS = 0.22-0.26) were detected in both populations. The 10 novel polymorphic microsatellite loci used in this study will be useful for future genetic mapping studies and for characterizing population structures, monitoring genetic diversity for successful aquaculture management, and developing conservation strategies for manila clam populations in Korea.

Role of the superior turbinate when performing endoscopic endonasal transsphenoidal approach.

BACKGROUND: This study examined the relationship between the superior turbinate and natural ostium of the sphenoid sinus, as seen during the endoscopic endonasal transsphenoidal approach (EETSA) for sellar lesions and described how to enter the sphenoethmoid cell safely for complete exposure of the sellar floor, including adjacent vital structures such as the prominence of the optic nerve and carotid artery. MATERIALS AND METHODS: This study retrospectively reviewed the medical records and operative findings of 154 patients, who underwent EETSA between February 2009 and February 2011. We evaluated the location of the natural ostium of the sphenoid sinus relative to the superior turbinate and revealed the clinical significance of the superior turbinate as a surgical guide to enter into the sphenoethmoid cell during EETSA. RESULTS: The natural ostium of the sphenoid sinus was located medially to the posteroinferior end of the superior turbinate in 151 (98%) patients. In 1 patient, the natural ostia of the sphenoid sinus were located lateral to the superior turbinate bilaterally. Sphenoethmoid cell was encountered in 53 (34%) patients. We could easily enter the sphenoethmoid cell at the point where the superior turbinate was attached to the anterior wall of the sphenoid sinus. CONCLUSIONS: The superior turbinate is a good surgical landmark for identifying the natural ostium of the sphenoid sinus and as a guide for the surgical entrance to the sphenoethmoid cell extending to the sphenoid sinus during EETSA.

A multicenter, phase II trial of everolimus in locally advanced or metastatic thyroid cancer of all histologic subtypes.

BACKGROUND: This phase II study investigated the efficacy and safety of everolimus, an inhibitor of mammalian target of rapamycin (mTOR), in locally advanced or metastatic thyroid cancer. PATIENTS AND METHODS: Patients with thyroid cancer of any histology that was resistant or not appropriate for (131)I received everolimus 10 mg daily orally until unacceptable toxicity or disease progression. The primary end point was disease control rate [partial response (PR) + stable response ≥12 weeks]. Secondary end points included response rates, clinical benefit (PD + durable stable disease (SD)], progression-free survival (PFS), overall survival, duration of response, and safety. RESULTS: Thirty-eight of 40 enrolled patients were evaluable for efficacy. The disease control rate was 81% and two (5%) patients achieved objective response; their duration of response was 21+ and 24+ weeks. Stable disease (SD) and progressive disease was reported in 76% and 17% of patients, respectively. Seventeen (45%) patients showed durable SD (≥24 weeks) and clinical benefit was reported in 19 (50%) patients. Median PFS was 47 weeks [95% confidence interval (CI) 14.9-78.5]. Calcitonin, CEA, and thyroglobulin concentrations were ≥50% lower than baseline in three (30%) and four (44%) patients with medullary thyroid cancer and five (33%) patients with PTC, respectively. The most common treatment-related adverse events were mucositis (84%), anorexia (44%), and aspartate transaminase/alanine transaminase elevation (26%). CONCLUSIONS: Everolimus had a limited activity with low response rate in locally advanced or metastatic thyroid cancer. Reasonable clinical benefit rate and safety profile may warrant further investigation. CLINICALTRIALSGOV NUMBER: NCT01164176.

Interleukin-8 and its receptor CXCR2 in the tumour microenvironment promote colon cancer growth, progression and metastasis.

BACKGROUND: Colorectal cancer (CRC) is a leading cause of death in the United States. Increased level of interleukin-8 (IL-8) and CXCR2 on tumours and in the tumour microenvironment has been associated with CRC growth, progression and recurrence in patients. Here, we aimed to evaluate the effects of tissue microenvironment-encoded IL-8 and CXCR2 on colon cancer progression and metastasis. METHODS: A novel immunodeficient, skin-specific IL-8-expressing transgenic model was generated to evaluate colon cancer growth and metastasis. Syngeneic mouse colon cancer cells were grafted in CXCR2 knockout (KO) mice to study the contribution of CXCR2 in the microenvironment to cancer growth. RESULTS: Elevated levels of IL-8 in the serum and tumour microenvironment profoundly enhanced the growth of human and mouse colon cancer cells with increased peri-tumoural angiogenesis, and also promoted the extravasation of the cancer cells into the lung and liver. The tumour growth was inhibited in CXCR2 KO mice with significantly reduced tumour angiogenesis and increased tumour necrosis. CONCLUSION: Increased expression of IL-8 in the tumour microenvironment enhanced colon cancer growth and metastasis. Moreover, the absence of its receptor CXCR2 in the tumour microenvironment prevented colon cancer cell growth. Together, our study demonstrates the critical roles of the tumour microenvironment-encoded IL-8/CXCR2 in colon cancer pathogenesis, validating the pathway as an important therapeutic target.

Brain metastases from colorectal cancer: the role of surgical resection in selected patients.

AIM: Brain metastasis is infrequent in colorectal cancer patients, and the prognosis is poor. In this retrospective study survival and prognostic factors were determined in patients with brain metastasis from colorectal cancer. METHOD: Between 1997 and 2006, 39 patients with brain metastasis from colorectal cancer who survived more than 1 month were identified. Data were collected with regard to patient characteristics, location and stage of the primary tumour, extent and location of metastatic disease, and treatment modalities used. RESULTS: Most (79.5%) patients had pulmonary metastases before brain metastasis, and the brain was the site of solitary metastasis in only one patient. The most frequent symptom was weakness [18 (43.6%) patients]. Overall median survival was 5.0 months and the 1- and 2-year survival rates were 21.8 and 9.1%, respectively. Univariate analysis revealed uncontrolled extracranial metastases (P = 0.019), multiple brain lesions (P = 0.026), bilateral brain metastases (P = 0.032) and serum carcinoembryonic antigen levels greater than 5 ng/ml (P = 0.008) to be poor prognostic factors. The median survival after the diagnosis of brain metastasis was significantly longer in patients who underwent surgical resection (15.2 ± 8.0 months) than in those treated by other modalities (P = 0.001). Treatment modality was the only independent prognostic factor for overall survival in patients with brain metastases from colorectal cancers (P = 0.015). CONCLUSION: Aggressive surgical resection in selected patients with brain metastases from colorectal cancer may prolong survival, even in the presence of extracranial metastatic lesions.

ATRX induction by mutant huntingtin via Cdx2 modulates heterochromatin condensation and pathology in Huntington's disease.

Aberrant chromatin remodeling is involved in the pathogenesis of Huntington's disease (HD) but the mechanism is not known. Herein, we report that mutant huntingtin (mtHtt) induces the transcription of alpha thalassemia/mental retardation X linked (ATRX), an ATPase/helicase and SWI/SNF-like chromatin remodeling protein via Cdx-2 activation. ATRX expression was elevated in both a cell line model and transgenic model of HD, and Cdx-2 occupancy of the ATRX promoter was increased in HD. Induction of ATRX expanded the size of promyelocytic leukemia nuclear body (PML-NB) and increased trimethylation of H3K9 (H3K9me3) and condensation of pericentromeric heterochromatin, while knockdown of ATRX decreased PML-NB and H3K9me3 levels. Knockdown of ATRX/dXNP improved the hatch rate of fly embryos expressing mtHtt (Q127). ATRX/dXNP overexpression exacerbated eye degeneration of eye-specific mtHtt (Q127) expressing flies. Our findings suggest that transcriptional alteration of ATRX by mtHtt is involved in pericentromeric heterochromatin condensation and contributes to the pathogenesis of HD.

The efficacy of portal vein embolization prior to right extended hemihepatectomy for hilar cholangiocellular carcinoma: a retrospective cohort study.

BACKGROUND/PURPOSE: Preoperative portal vein embolization was introduced to minimize complications after extended hepatectomy. This retrospective cohort study was conducted to compare outcomes with and without portal vein embolization before hepatectomy for hilar cholangiocellular carcinoma. METHODS: This study was conducted with 35 patients who underwent right extended hemihepatectomy for hilar cholangiocellular carcinoma from 2001 to 2008. Preoperative portal vein embolization was performed in 14 patients (embolization group) and not performed in 21 patients (non-embolization group). RESULTS: The groups did not differ in terms of sex, age, operative time, transfusion, postoperative serum bilirubin level, prothrombin time, and length of intensive care unit (ICU) stay. Although blood loss was higher in the embolization group than in the non-embolization group (P = .009), no major complications were observed between embolization and resection. At presentation, future liver remnant was smaller in the embolization group (19.8%, range 16-35%) than in non-embolization group (28.3%, 15-47%; P = .001). After embolization, the volume of the future liver remnant increased significantly to 27.2% (range, 23-42%; P = .001). Future liver remnants just before operation were similar in both groups (P > .99). There was no significant difference in terms of the rate of morbidity and in-hospital mortality. No statistically significant differences were observed in disease-free survival (P = .52) and overall survival (P = .30). CONCLUSIONS: Portal vein embolizations do not increase the rate of morbidity, in-hospital mortality, local recurrence and system metastasis. Therefore it can be considered safe and effective for patients with small future liver remnants. Embolization can lessen postoperative liver failure and widen the indication of the surgical resection, especially in patients with marginal future liver remnants.

Massive gastrointestinal bleeding due to the rupture of arterial aneurysm in Behçet's disease: case report and literature review.

Massive gastrointestinal bleeding is a very rare manifestation of gastrointestinal Behçet's disease, mainly from the gastrointestinal mucosal lesions. We report herein the case of a 50-year-old man with intestinal Behçet's disease who suffered massive hemorrhage from ruptured arterial aneurysm. Colonoscopy demonstrated large amount of fresh blood in the entire colon, but we were not able to localize bleeding focus anywhere in the colon. Angiography was performed and it revealed that a small aneurysm on the right ileocolic artery with apparent extravasation of contrast material. A guiding catheter was inserted to a right ileocolic artery and superselective arterial embolization using microcoils was successful. Following this procedure, the gastrointestinal bleeding gradually subsided and completely stopped within a few days. He is now treating with prednisolone and sulfasalazine without recurrent bleeding until now.

Altered frequency and migration capacity of CD4+CD25+ regulatory T cells in systemic lupus erythematosus.

OBJECTIVES: To determine the frequency and chemokine receptor-related migratory capacity of CD4(+)CD25(+) regulatory T cells (Tregs) and their association with clinical parameters in patients with SLE. METHODS: The expression of CD4, CD25, FoxP3 and CCR4 was examined with flow cytometry after staining with fluorescence-conjugated antibodies in 20 patients with SLE, 20 patients with RA and 21 age- and sex-matched healthy controls. For analysis of migration capacity in 24-well chemotaxis chambers, sorted cells were stimulated with ligands of CCR4, CCL17 and CCL22 and analysed with FACScan. Correlations between the number of Tregs and CCR4(+) Treg cells and clinical parameters were analysed. RESULTS: The numbers of Tregs(bright) and CCR4(+) Tregs(bright) were significantly decreased in the patients with SLE compared with healthy controls. The number of Tregs(bright) was negatively correlated with the levels of anti-dsDNA antibody and the number of CCR4(+) Tregs(bright) had a positive correlation with the levels of C(3). Percentage of migrated Tregs(bright) by CCL17 or CCL22 was significantly decreased in the patients with SLE compared with healthy controls. CONCLUSIONS: These results suggest that altered frequency of Tregs and CCR4(+) Tregs(bright) and decreased migratory capacity of Tregs might be involved in the pathogenesis of SLE and indicate that targeting the Tregs can be a new therapeutic strategy in SLE.

Epidural hematoma mimicking transverse myelitis in a patient with primary antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disease, and its most critical pathologic process is thrombosis, which may explain most of the clinical features. Acute management of thrombosis involves immediate anticoagulation. Acute proximal venous thrombosis can be managed with thrombolytic therapy to reduce the long-term complications of the postthrombotic syndrome (pain, swelling, skin discoloration, or ulceration) and perform recanalization of occluded vessels. However, thrombolytic therapies are associated with high risks of bleeding. To our knowledge, this is the first report of epidural hematoma mimicking transverse myelitis after catheter-directed thrombolysis in a patient with primary APS. A 42-year-old male was admitted with sudden onset pain and swelling on left lower extremity. Venography demonstrated multiple thrombi on superficial femoral vein, common femoral vein, common iliac vein, and external iliac vein. Laboratory tests indicated the presence of IgM anticardiolipin antibody. He was diagnosed with primary APS with multiple venous thrombi. He was treated with urokinase (200,000/h) as thrombolytic therapy. After 1 day, he complained both leg weakness and urinary dysfunction. T1- and T2-weighted magnetic resonance images of spine showed about 8 cm-sized mass, suggesting hematoma on the posterior epidural space at thoracolumbar area. Despite the successful evacuation of hematoma, neurologic symptoms persisted and he is now receiving aspirin, warfarin, and physical therapy.

Antipyretic, analgesic, and anti-inflammatory activities of the seaweed Sargassum fulvellum and Sargassum thunbergii in mice.

Dichloromethane, ethanol, and boiling water extracts of the brown seaweeds Sargassum fulvellum and Sargassum thunbergii were examined for antipyretic, analgesic, and anti-inflammatory activities in mice. The activities were evaluated against yeast-induced pyrexia, tail-flick test, and phorbol myristate acetate-induced inflammation (edema, erythema, and blood flow). The dichloromethane extract (0.4 mg/ear) of Sargassum fulvellum inhibited an inflammatory symptom of mouse ear edema by 79.1%. The ethanol extract (0.4 mg/ear) of Sargassum thunbergii also inhibited edema by 72.1%. No acute toxicity was observed after p.o. administration of each extract (5 g/kg bw). These findings are consistent with various claims that these seaweeds can be used as remedies for inflammation-related symptoms.

Methanolic extract of Pterocarpus santalinus induces apoptosis in HeLa cells.

Ptercarpus santalinus (Fabaceae) has been used as a folk remedy in Korea, and it has been shown to exhibit antiinflammations, antiulcers and anticancer effects. In this study, therefore, we report the cytotoxic activity and the mechanism of cell death exhibited by the methanol extract of Ptercarpus santalinus (MEPS) against human cervical adenocarcinoma cell line, HeLa. Treatment of HeLa cells with various concentrations of MEPS resulted in growth inhibition and induction of apoptosis in a dose-dependent manner as determined by cell viability, chromatin condensation, DNA fragmentation and sub-G1 phase accumulation. In Western blot analysis, apoptosis in the HeLa cells was associated with the release of cytochrome C from mitochondria into the cytosol, activation of caspases-3, -8, -9 and proteolytic cleavage of PARP. These results suggest that MEPS exhibits antiproliferative effect on HeLa cells via apoptosis, and it may be a potential candidate in field of anticancer drug discovery.

Structure-activity relationship of neuropeptide gamma derived from mammalian and fish.

This study of relationship between structure and biologic activity was performed using five neuropeptide gammas [NPgamma; mammalian-NPgamma (M-NPgamma), trout-NPgamma (T-NPgamma), goldfish-NPgamma (G-NPgamma), bowfin-NPgamma (B-NPgamma), and shark-NPgamma (S-NPgamma)]. Circular dichroism (CD) spectra showed that all peptides took random structure in buffer solution. In neutral and acidic liposomes, M-NPgamma, T-NPgamma, B-NPgamma, and S-NPgamma still adopted random structure, while G-NPgamma had an alpha-helical structure. The biologic activity of NPgammas has been estimated by their effects on the intestinal motility and arterial relaxation. The intestinal motility was investigated with rat duodenum (RD), carp intestine (CI), and guinea-pig ileum (GPI). The arterial relaxing effect was tested with guinea-pig aorta (GPA) and rat mesenteric artery (RMA). In RD, the order of potency compared with the EC50 value was M-NPgamma >> S-NPgamma >> B-NPgamma >> G-NPgamma >> T-NPgamma. G-NPgamma was the most contractile agent in CI. S-NPgamma was the most contractile agent in GPI. Using an arterial relaxing test, the order of potency was G-NPgamma >> T-NPgamma >> B-NPgamma >> S-NPgamma >> M-NPgamma in GPA, and all NPgammas remarkably reduced relaxing activity in RMA. Despite their structural similarities to NPgammas, G-NPgamma has high affinity to tachykinin receptor-binding sites in GPA and CI, indicating an alpha-helical structure may have a critical role for receptor binding. However, an alpha-helical structure does not play a critical role in recognizing receptor-binding sites in RD and GPI.

Ultraviolet B irradiation of human skin induces an angiogenic switch that is mediated by upregulation of vascular endothelial growth factor and by downregulation of thrombospondin-1.

BACKGROUND: We have previously demonstrated that skin-specific overexpression of the endogenous angiogenesis inhibitor thrombospondin (TSP)-1 prevented chronic ultraviolet (UV) B-induced angiogenesis, inflammatory cell infiltration and cutaneous photodamage in mice. OBJECTIVES: To elucidate the mechanisms by which acute UVB-induced angiogenesis induces dermal damage, and to study the molecular regulation of acute UVB-induced angiogenesis in human skin. METHODS: We subjected five healthy volunteers to acute UVB irradiation (2 minimal erythema doses) and performed histological analysis at 48 h after UVB irradiation. RESULTS: Histology revealed epidermal hyperplasia, infiltration of elastase-producing neutrophils and elastin fibre damage. Immunohistochemistry for CD31 demonstrated pronounced angiogenesis with a significant increase in both vascular density and vessel size, associated with increased endothelial cell proliferation. Whereas constitutive expression of TSP-1 but only weak expression of vascular endothelial growth factor (VEGF) were detected in normal human epidermis, pronounced downregulation of TSP-1 and upregulation of VEGF were observed in epidermal keratinocytes after acute UVB irradiation. These findings were confirmed by quantitative reverse transcription-polymerase chain reaction analysis after UVB irradiation of cultured HaCaT keratinocytes in vitro. CONCLUSIONS: Together, these data indicate that a disruption of the balance between VEGF and TSP-1 expression leads to a UVB-induced angiogenic switch, facilitating the infiltration of elastase-producing leucocytes and cutaneous photodamage.

Use of Pi5(t) markers in marker-assisted selection to screen for cultivars with resistance to Magnaporthe grisea.

Identification of the PCR markers tightly linked to genes that encode important agronomic traits is useful for marker-assisted selection (MAS). The rice Pi5(t) locus confers broad-spectrum resistance to Magnaporthe grisea, the causal agent of rice blast disease. It has been hypothesized that the Pi5(t) locus carries the same gene as that encoded by the Pi3(t) and Pii(t) loci. We developed three PCR-based dominant markers (JJ80-T3, JJ81-T3, and JJ113-T3) from three previously identified BIBAC clones-JJ80, JJ81, and JJ113-that are linked to the Pi5(t) locus. PCR analysis of 24 monogenic lines revealed that these markers are present only in lines that carry Pi5(t), Pi3(t), and Pii(t). PCR and DNA gel-blot analysis of candidate resistance lines using JJ80-T3, JJ81-T3, and JJ113-T3 indicated that Tetep is the likely donor of Pi5(t). Of the 184 rice varieties tested, 34 carried the JJ80-T3-, JJ81-T3-, and JJ113-T3-specific bands. Disease evaluation of those 34 varieties revealed that all conferred resistance to PO6-6. The genomic structure of three of these resistant varieties (i.e., IR72, Taebaeg, Jahyangdo) is most similar to that of Pi5(t). Our results demonstrate the usefulness of the JJ80-T3, JJ81-T3, and JJ113-T3 markers for MAS for M. grisea resistance.