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Nearly isogenic lines (NILs) of rice (Oryza sativa) differing at a locus conferring resistance to the pathogen Xanthomonas oryzae pv. oryzae were surveyed with 123 DNA markers and 985 random primers using restriction fragment length plymorphism (RFLP) and random amplified polymorphic DNA (RAPD) analysis. One chromosome 11 marker (RG103) detected polymorphism between the NILs that cosegregated with Xa21. All other chromosome 11 DNA markers tested were monomorphic between the NILs, localizing the Xa21 introgressed region to an 8.3 cM interval on chromosome 11. Furthermore, we identified two polymerase chain reaction (PCR) products (RAPD2148 and RAPD818) that detected polymorphisms between the NILs. Genomic sequences hybridizing with RAPD818, RAPD248 and RG103 were duplicated specifically in the Xa21 NIL. All three markers cosegregated with the resistance locus, Xa21, in a F2 population of 386 progeny. Based on the frequency with which we recovered polymorphic Xa21-linked markers, we estimated the physical size of the introgressed region to be approximately 800 kb. This estimation was supported by physical mapping (using pulsed field gel electrophoresis) of the sequences hybridizing with the three Xa21-linked DNA markers. The results showed that the three Xa21-linked markers are physically close to each other, with one copy of the RAPD818 sequences located within 60 kb of RAPD248 and the other copy within 270 kb of RG103. None of the enzymes tested generated a DNA fragment that hybridized with all three of the markers indicating that the introgressed region containing the resistance locus Xa21 is probably larger than 270 kb.

Data hiding in a cover image can be used to assist in secure message communication on the Internet. In this paper, we proposed a hybrid data hiding scheme that is a combination of least significant bit substitution (LSB), exploiting modification direction (EMD) and modification of prediction errors (MPE). The aim is to maintain a balance between embedding quality and embedding capacity where high payload is the motive. The image is first embedded by EMD, or LSB followed by EMD only if the peak signal-to-noise ratio (PSNR) is greater or equal T1 dB (45 dB). The remainder payload will be embedded by recursive MPE until the PSNR of the stego-image reaches T2 dB (35 dB). Experimental results showed that the proposed scheme has a higher embedding capacity while maintaining high visual quality of the stego-image than any of the individual method. [ABSTRACT FROM AUTHOR]

Pt0.5− xMn0.5+ x films were prepared by sputtering deposition of Pt foil and Mn target to study the order-disorder transition from a thermodynamic metastable fcc (A1) phase to L10 phase. Both Differential Scanning Calorimetry and High Temperature X-Ray Diffraction studies showed the phase transformation from fcc to the L10 structure for the Pt0.50Mn0.50 and Pt0.40Mn0.60 samples but along completely different kinetic paths. A composition dependent phase transformation was observed by comprehensive Differential Scanning Calorimetry studies on a series of Pt0.5− xMn0.5+ x samples. The changes of the lattice parameter and the cell volume of L10 Pt0.5− xMn0.5+ x as a function of composition suggest that the anti-site is not the dominant point defect for L10 Pt0.5− xMn0.5+ x. [ABSTRACT FROM AUTHOR]

It is shown in this paper that many new sensitive phase photonic crystal devices will be developed, if some existing problems can be overcome. The main problems are the rapid change of light intensity around the defect mode and the influence of the substrate. The method for overcoming these problems is to construct the defective photonic crystal in a heterostructure or an asymmetric structure. The phase properties of asymmetric one-dimensional photonic crystals with couple defects are revealed in this paper. As examples, a phase modulator and a phase switch with very high sensitivity are demonstrated. [ABSTRACT FROM AUTHOR]

The reaction sequence of 3He(α,γ)7Be(α,γ)11C(p,γ)12N to CNO could be an alterative way of 3α →12C to convert 3He into CNO. It may become important in some specific environments, such as in a very massive star with low metallicity. Whether it is significant depends on the reactions involved, one of the important reactions is the 11C p-capture competing with its β + decay. The S factor for the 11C(p,γ)12N direct capture was obtained in our previous work. This work is to update the reaction rate by adding uncertainty and fitting with the Thielemann format. With the new rate, nucleosynthesis simulations are performed to study the bridge of the p-p chains to CNO through the above sequence. [Copyright &y& Elsevier]

The prevalence of endocrine-disrupting chemicals (EDCs) in the aquatic environment has been associated with the wide detection of alterations in the development and physiology of vertebrates. Zebrafish, as a model species, has been extensively used in toxicological research. In this review, we focus on recent published evidence of the harmful effects of EDCs on reproductive function in zebrafish, including skewed sex ratio, immature gonads, diminished sexual behaviour, decreased sperm count, reduced spawning and fertilization. These impairments mostly result from disruption to sex-steroid hormones induced by endocrine disruptors. We also discuss other effects of exposure to EDCs. In EDC exposure research, despite incomplete assessments of altered gonad histopathology and sexual behaviour, these present potential effective biomarkers or pathways for evaluating the reproductive function in zebrafish on EDC exposure. To date, the pernicious effects of some EDCs on the reproductive performance in laboratory zebrafish are well understood; however, similar alterations remain for further determination in wild-type fish and more kinds of EDCs. More studies should be performed under established scientific regulatory criteria to investigate the impact of EDCs on reproduction in zebrafish. Moreover, further research is required to explain the definite mechanism of sexual differentiation, which helps in understanding the shift of sexual phenotype with EDC exposure., (© 2014 Blackwell Verlag GmbH.)

The rice blast resistance (R) gene Pi-ta mediates gene-for-gene resistance against strains of the fungus Magnaporthe grisea that express avirulent alleles of AVR-Pita. Using a map-based cloning strategy, we cloned Pi-ta, which is linked to the centromere of chromosome 12. Pi-ta encodes a predicted 928-amino acid cytoplasmic receptor with a centrally localized nucleotide binding site. A single-copy gene, Pi-ta shows low constitutive expression in both resistant and susceptible rice. Susceptible rice varieties contain pi-ta(-) alleles encoding predicted proteins that share a single amino acid difference relative to the Pi-ta resistance protein: serine instead of alanine at position 918. Transient expression in rice cells of a Pi-ta(+) R gene together with AVR-Pita(+) induces a resistance response. No resistance response is induced in transient assays that use a naturally occurring pi-ta(-) allele differing only by the serine at position 918. Rice varieties reported to have the linked Pi-ta(2) gene contain Pi-ta plus at least one other R gene, potentially explaining the broadened resistance spectrum of Pi-ta(2) relative to Pi-ta. Molecular cloning of the AVR-Pita and Pi-ta genes will aid in deployment of R genes for effective genetic control of rice blast disease.

Pulsed-field gel electrophoresis (PFGE) has been applied to analyze the rice nuclear genome. Probing 56 RFLP probes selected from the 12 rice chromosomes to PFGE blots of nine rare-cutting restriction enzymes revealed that there are relatively high numbers of 'rare-cutting' restriction sites in the rice genome. The average sizes of restriction fragments detected by single-copy probes are smaller than 200 kb for all of the rare-cutting restriction enzymes examined. Sizes of fragments detected by repetitive probes are variable, depending on the probes analyzed. By using PFGE, a tandemly repeated sequence, Os48, was found to be tightly linked to telomeric tandem repeats but not physically linked to r5s genes with which sequence homology had been observed. Relationships between genetic and physical distances have been established for three different chromosomal segments. In these regions 1 cm corresponds to ca. 260 kb on average. Analysis of a cluster of RFLP markers on chromosome 3 revealed that genetically clustered RFLP markers are also physically closely linked, suggesting that clustering of genetic markers may result in part from uneven distribution of single-copy sequences.

Dinucleotide microsatellites have been characterized and used as genetic markers in rice. Screening of a rice genomic library with poly(dG-dA).(dC-dT) and poly(dG-dT).(dC-dA) probes indicated that (GA)n repeats occurred, on average, once every 225 kb and (GT)n repeats once every 480 kb. DNA sequencing of ten randomly selected microsatellites indicated that the numbers of repeats ranged from 12 to 34 and that the patterns of microsatellites in rice were similar to those of humans and other mammals. Primers to these microsatellite loci as well as to four published microsatellite-containing sequences have been designed and degrees of polymorphism has been examined with 20 rice accessions. Multiple alleles, ranging from 5 to 11, have been observed at all the microsatellite loci in 20 rice accessions. Alleles specific to two cultivated subspecies, indica and japonica, were found in some microsatellite loci. Heterozygosity values of all the microsatellite markers were significantly higher than those of RFLP markers, based upon a parallel comparison. Ten microsatellite loci have been genetically mapped to four rice chromosomes. The genomic distribution of microsatellites appears to be random in rice.

Telomeres and telomere-associated satellites of rice were genetically and physically analyzed by pulsed-field gel electrophoresis (PFGE) using Arabidopsis telomeric DNA and rice satellite sequences as probes. We demonstrate that Arabidopsis telomeric sequences hybridize to rice telomeres under the conditions of high stringency. Using the Arabidopsis probe, multiple, discrete telomeric fragments could be identified on pulsed-field gel blots of rice DNAs digested with rare-cutting restriction enzymes. Most of the telomeric bands larger than 300 kb are physically linked with satellite bands as revealed by PFGE. Some of the telomeric and satellite bands segregate in a Mendelian fashion and are highly reproducible. Three such telomeric bands have been mapped to the distal ends of RFLP linkage groups: Telsm-1 on chromosome 8, Telsa-1 on chromosome 9 and Telsm-3 on chromosome 11. One segregating satellite band was mapped to an internal region of chromosome 10. Telomeric fragments were shown not only to be genetically linked to but also physically linked (based on PFGE) to the terminal RFLP markers. The physical distance from telomeric sequences to a distal RFLP marker, r45s gene, on chromosome 9, is 200 kb while the distance from telomeric sequences to RG98, a terminal RFLP marker on chromosome 11, is 260 kb. Physical maps of the telomere regions of chromosome 9 and chromosome 11 are presented.

A prerequisite for physical mapping by pulsed-field gel electrophoresis (PFGE) is the saturation of a given genome or chromosomal region with single copy markers. One possible way to achieve this goal is by construction of a saturated restriction fragment length polymorphism (RFLP) map. Although RFLP maps are now available for many plant species, only a few systems provide the high density of markers (at least one marker every 1000 kb) required for long-range physical mapping using PFGE. At present, only four plant systems, Arubidofm (1,2), tomato (3), potato (4,5), and rice (6), have a sufftcient density of markers. These species are characterized by relatively small genomes when compared to other plants, with an average distance between individual RFLP markers of 400-800 kb. PFGE in combination with the digestion of DNA, using rare-cutting restriction enzymes, is able to bridge these gaps, and will allow the construction of long-range physical maps for regions of these plant genomes (7). PFGE has already been used in a number of species to construct long-range restriction maps of a number of gene families and repeated DNA sequences (8-12).