Development of a molecular marker for the Pi1 gene based on the association of the SNAP protocol with the touch-up gradient amplification method.

Genetic resistance is the most effective and eco-friendly approach to combat rice blast. The application of resistance genes may be facilitated by the availability of molecular markers that allow marker-assisted selection during the breeding process. The Pi1 gene, considered to be a broad-spectrum resistance gene, might contribute to enhancing resistance to rice blast, but it lacks a suitable marker that can be used. In this study, we investigated nucleotide polymorphism in the Pik locus and combined the SNAP protocol with the touch-up gradient amplification method to develop a SNAP marker. The Pi1 SNAP marker could distinguish Pi1 from Pik alleles, and when used for screening a germplasm bank and an F2 population, it consistently identified germplasms carrying the Pi1 gene. The P1 SNAP marker offers as advantages to involve only the presence/absence analysis of PCR amplicons resolved on an agarose gel.

Identification of a Pi9-Containing Rice Germplasm with a Newly Developed Robust Marker.

The Pi9 gene in rice, originating from Oryza minuta, is an effective resistance gene for controlling rice blast disease. However, currently available linked DNA markers do not accurately identify the function of Pi9, thus hindering its efficient incorporation into new cultivars through marker-assisted selection (MAS). In addition, no known Pi9-containing rice germplasm is available to breeders. In the present study, DNA sequence variation of Pi9 alleles and their family members was analyzed in 40 diverse rice germplasm accessions from the AA genome to develop a robust Pi9 marker. In total, 29 DNA primers of 20 to 23 nucleotides were designed and each possible combination of primer pairs was used to detect Pi9. Only one combination of DNA primers, KS28/KS6, was identified to specifically detect Pi9 in the monogenic line IRBL9-W. The presence of Pi9 was verified with the predicted Pi9-specific blast reaction. Subsequently, 201 genetically diverse mini-core rice accessions from 114 countries were screened with KS28/KS6. One germplasm, IR 9660-48-1-1-2, was identified to carry Pi9 and the function of Pi9 was verified with pathogenicity assays. This robust Pi9 marker and a rice germplasm, IR9660-48-1-1-2 (GSOR310687), carrying Pi9 can be used to improve blast resistance with a MAS approach.

Factors predicting survival after diagnosis of laryngeal cancer.

Survival in patients with laryngeal cancer has not increased remarkably within the last years. It is presumed that a variety of factors act jointly in predicting survival after diagnosis: tumour stage, tumour site, treatment approaches, age and comorbidities. The aim of this German clinical multi-centre study is to present results from multivariate analysis. A retrospective cohort study was conducted in four hospitals in South-West Germany. Incident cases with laryngeal squamous cell carcinoma were included for the years 1998 to 2004, resulting in a population sample of 594 patients. Multivariate regression analysis was performed using the Cox proportional hazards model. Patients were followed up for 64.1months on average. Overall 5-year survival was 66% (95% confidence interval (CI): 62-70%). The strongest risk factors in multivariate analysis were age at first diagnosis (hazard ratio (HR): 1.5; 95% CI: 1.5-1.7 per each additional 10years), tumour stage, and the development of recurrences (HR 3.1; 95% CI: 2.3-4.2) or second primary carcinomas (HR 2.1; 95% CI: 1.4-3.1). A somewhat weaker effect was shown for patients with comorbidities (using Charlson's comorbidity index). The choice of treatment did not strongly affect survival when adjusting for other factors, possibly because the optimal treatment approach was applied for the specific constitution and requirements of each patient. For future research it would be desirable to study the effect of treatment on quality of life in multivariate analysis as well as other modifiable risk factors as smoking and drinking reduction or cessation after diagnosis.

Desflurane anesthesia after sevoflurane inhaled induction reduces severity of emergence agitation in children undergoing minor ear-nose-throat surgery compared with sevoflurane induction and maintenance.

Emergence agitation may occur after general anesthesia with volatile anesthetics in children. We designed this study to examine the emergence behavior of children undergoing ear-nose-throat surgery after sevoflurane induction and desflurane maintenance versus both sevoflurane induction and maintenance using a recently published Pediatric Anesthesia Emergence Delirium (PAED) scale. In 38 premedicated children aged 12 mo to 7 yr mask induction with sevoflurane was performed and they were randomly assigned to receive either sevoflurane (n = 19) or desflurane (n = 19) for maintenance of general anesthesia. Time to tracheal extubation, modified Aldrete score, emergence behavior, recovery complications, and pain scores were assessed. The PAED scale showed a significant advantage for desflurane (6 [0-15] versus 12 [2-20], maximum total score of 20 for severe agitation). Time to extubation was significantly shorter with desflurane than with sevoflurane (5.4 +/- 1.4 versus 13.4 +/- 1.8 min). The modified Aldrete score on arrival in the postanesthesia care unit (PACU) was significantly lower in children receiving sevoflurane for maintenance. Time to discharge from PACU to normal ward and the incidence of adverse effects were not significantly different between the groups. In conclusion, the use of desflurane for maintenance of anesthesia after sevoflurane induction in children is associated with less severe emergence agitation and faster emergence times.

Carbon stocks in organic matter fractions as affected by land use and soil management, with emphasis on no-tillage effect

Land use and soil management may affect both labile and humified soil organic matter (SOM) fractions, but the magnitude of these changes is poorly known in subtropical environments. This study investigated effects of four land use and soil management systems (forest, native pasture, and conventional tillage and no-tillage in a wheat/soybean succession) on (i) total soil organic carbon (SOC) stocks (0 to 250mm depth) and on (ii) carbon (C) stocks in labile (coarse, light) and humified (mineral-associated, humic substances) SOM fractions (0 to 25mm depth), in a Hapludox soil from southern Brazil. In comparison to the adjacent forest site, conventionally tilled soil presented 36 percent (46.2Mg ha-1) less SOC in the 0 to 250mm depth and a widespread decrease in C stocks in all SOM fractions in the 0 to 25mm depth. The coarse (>53 mum) and light (<1kg dm-3) SOM fractions were the most affected under no-tillage, showing 393 percent (1.22Mg C ha-1) and 289 percent (0.55Mg C ha-1) increases, respectively, in relation to conventional tillage. Similar results were observed for mineral-associated SOM and humic substance C pools (34 percent and 38 percent increases, respectively) under no-tillage. Compared with labile SOM fraction results, the percentual increments on C stocks in humified fractions were smaller; but in absolute terms this C pool yielded the highest increases (3.06 and 2.95Mg C ha-1, respectively). These results showed that both labile and humified organic matter are better protected under the no-tillage system, and consequently less vulnerable to mineralization. Humified SOM stabilization process involving interactions with variable charge minerals is probably important in maintaining and restoring soil and environmental quality in tropical and subtropical regions