Synchronicity of pollination and inoculation with Claviceps africana and its effects on pollen-pistil compatibility and seed production in sorghum

Sorghum ergot (caused by Claviceps africana) is a disease that affects sorghum seed development and yield. The interaction between pollen tube growth and hyphal development determines whether ovaries will be fertilized or colonized. Thus their respective deposition times on the stigma are critical. The effect of the time interval between pollination and inoculation on stigma receptivity and seed production was measured under field conditions in the male-sterile line A9 at Montecillo, State of México (2240m altitude). Pollination and inoculation treatments, from simultaneous application to 2 and 4h difference, were imposed when all stigmas on the panicle had emerged. Control panicles were either only pollinated or only inoculated. Eighteen hours later, pollen grains that adhered to, and germinated within the stigma, pollen tubes in the style and ovary, and fertilized pistils were counted. Pistils showing some disease expression (germinated spores, mycelium growth, or tissue necrosis) at 18, 48, and 72h were recorded. The number of diseased florets was registered at the dough growth stage, while number of seeds, grain yield and 100-seeds weight was measured at the physiological maturity. The pathogen applied in a water suspension of macro and secondary conidia caused a decrease in stigma receptivity; the greatest decrease (40-60%) occurred when the pollen and the inoculum were deposited almost simultaneously, regardless of which was deposited first. The route of the pollen tube was also the route for fungal infection. On average, treatments first inoculated had 60% more diseased florets and 36% less grain yield, 30% fewer seeds and seed size decreased 8%, than those first pollinated.     

Association and interaction of the IL4R,IL4, and IL13 loci with type 1 diabetes among Filipinos

In the search for genes involved in type 1 diabetes (T1D), other than the well-established risk alleles at the human leukocyte antigen loci, we have investigated the association and interaction of polymorphisms in genes involved in the IL4/IL13 pathway in a sample of 90 Filipino patients with T1D and 94 controls. Ten single-nucleotide polymorphisms (SNPs), including two promoter SNPs in the IL4R locus on chromosome 16p11, one promoter SNP in the IL4 locus on chromosome 5q31, and four SNPs--including two promoter SNPs--in the IL13 locus on chromosome 5q31 were examined for association, linkage disequilibrium, and interaction. We found that both individual SNPs (IL4R L389L; odds ratio [OR] 0.34; 95% confidence interval [CI] 0.17-0.67; P=.001) and specific haplotypes both in IL4R (OR 0.10; 95% CI 0-0.5; P=.001) and for the five linked IL4 and IL13 SNPs (OR 3.47; P=.004) were strongly associated with susceptibility to T1D. Since IL4 and IL13 both serve as ligands for a receptor composed, in part, of the IL4R alpha chain, we looked for potential epistasis between polymorphisms in the IL4R locus on chromosome 16p11 and the five SNPs in the IL4 and IL13 loci on chromosome 5q31 and found, through use of a logistic-regression model, significant gene-gene interactions (P=.045, corrected for multiple comparisons by permutation analysis). Our data suggest that the risk for T1D is determined, in part, by polymorphisms within the IL4R locus, including promoter and coding-sequence variants, and by specific combinations of genotypes at the IL4R and the IL4 and IL13 loci.     

Association of CTLA-4 variation with type I diabetes in Filipinos

The role of non-HLA single nucleotide polymorphisms from a panel of candidate genes in genetic susceptibility to type I diabetes (TID) among Filipinos was examined by PCR/SSOP typing of 90 patients and 94 controls, previously typed for the HLA class I and class II loci. We report the association of CTLA-4 A49G variation (cytotoxic T-lymphocyte associated-4) to TID among Filipinos, consistent with some but not all previous reports in other ethnic groups. The G allele frequency (0.61 versus 0.45, P=0.003) and GG genotype frequency (0.42 versus 0.22, P=0.004) were each increased in patients compared to controls, respectively. Among Filipinos, the CTLA-4 genotypes are associated with disease only in the presence of the predisposing DR3, 4, and 9 haplotypes (P=0.012). Compared to the AA genotype, the increased risk of diabetes predisposition is greatest in genotype GG bearing the DR susceptible alleles (DR3, 4, and 9) (odds ratio=4.6, P=0.001), demonstrating that non- HLA loci, acting in concert with HLA, can play potent roles in modifying susceptibility to TID.     

Total Phenols and Flavonoids in Germinated Barley Using Different Solvents

Sprouts are a source of secondary metabolites as phenolic compounds. Germination and the use of solvents can affect their content. The aim of this work was to identify the total content of phenols and flavonoids in ungerminated and germinated (3, 5, and 7 days) Esmeralda and Perla barley. Different solvents (water, 50 % acetone, 80 % methanol, 80 % ethanol) were used to recover total phenols and flavonoids. The 7-day germination proved to be ideal for total phenol and flavonoid obtention from Esmeralda barley and the highest total phenol and flavonoid content in Perla variety was observed at 5 and 7 days of germination, respectively. Methanol and ethanol (80 %) yielded the highest extraction percentage of total phenols; 50 % acetone recovered the highest flavonoid concentrations in Esmeralda barley and 80 % methanol in Perla barley. The highest total phenol concentration was obtained from Perla samples at 13.60 mg GAE/g, and the highest total flavonoids were observed in Esmeralda barley at 1.73 mg QE/g. A high correlation was found between the concentration of phenols (0.995) and total flavonoids (0.780) with the radicle size in the Esmeralda samples.     

Development of individual recognition of female southern elephant seals, Mirounga leonina, from Punta Norte Península Valdés, applying principal components analysis

Aim The development of software able to provide individual recognition of southern elephant seals, as a tool to study colonies. This analysis was performed within a framework of studies concerning environmental dispersion produced by the El Niño Southern Oscillation effect in the Southern Ocean Ecosystem. Location Digital photographs of reproductive female elephant seals were taken at Punta Norte (Península Valdés, Patagonia; 42°05′ S, 63°45′ W) during the 2002 breeding season (August to November). The data set under analysis is composed of 96 elephant seal images for a population of 56 individuals. Method Identification of specimens was carried out using digital pictures taken with a digital video camera, and processed through the ‘Eigenfaces’ method, which is based on principal components analysis. Special care was taken to control possible variations among images of the same individual, like distance, angle, light intensity, etc. To deal with these variations, an initial alignment procedure is proposed to have all images framed; in addition an initial histogram equalization was used which attenuates any potential variation in light intensity. The software was developed in IDL5.5 language. Results A complete set of empirical results is displayed showing the potential effectiveness of this technique. Individual recognition and pertinence to different population subsets (harems) tests have been carried out. A principal result of this work is that all 96 elephant seal images (representing 56 individuals) were correctly identified. Conclusion The Eigenfaces method can be used successfully for identification of elephant seals. With the appropriate preparatory treatment of images, high performance results can be expected.     

Role of cAMP-Dependent Protein Kinase on Acute Picrotoxin-Induced Seizures

cAMP-dependent protein kinase (PKA) is a major modulator of synaptic transmission likely to be involved in molecular and cellular events leading to epileptogenesis, but little is known about how it affects the onset of acute epileptic seizures. In this study, we determined PKA enzymatic activity in the rat hippocampus during picrotoxin-induced seizures, using H-9 dihydrochloride, a PKA inhibitor, to investigate the in vivo effects of this enzyme on seizures induced by picrotoxin microdialysis in the rat hippocampus. No significant modifications were found in PKA activity during seizures as compared to control rats, but H-9 dihydrochloride microperfusion (100 μM) prevented picrotoxin seizures in 50% of the animals and significantly reduced the mean number of seizures and mean seizure duration. These results suggest that acute picrotoxin-induced seizures occur without an increase in hippocampal PKA activity, but reduced PKA-mediated phosphorylation protects against picrotoxin seizures, probably by increasing the inhibitory potential of GABA_A receptors. The possibility of other targets for H-9 dihydrochloride, such as PKC, PKG or CAMKII, however, cannot be ruled out.