Somsak Apisitwanich

Bio: Somsak Apisitwanich is an academic researcher from Kasetsart University. The author has contributed to research in topics: Genome & Leiolepis reevesii. The author has an hindex of 10, co-authored 32 publications receiving 335 citations. Previous affiliations of Somsak Apisitwanich include Mae Fah Luang University.

Karyotypic evolution in squamate reptiles: comparative gene mapping revealed highly conserved linkage homology between the butterfly lizard (Leiolepis reevesii rubritaeniata, Agamidae, Lacertilia) and the Japanese four-striped rat snake (Elaphe quadrivirgata, Colubridae, Serpentes)

Abstract: The butterfly lizard (Leiolepis reevesii rubritaeniata) has the diploid chromosome number of 2n = 36, comprising two distinctive components, macrochromosomes and microchromosomes To clarify the conserved linkage homology between lizard and snake chromosomes and to delineate the process of karyotypic evolution in Squamata, we constructed a cytogenetic map of L reevesii rubritaeniata with 54 functional genes and compared it with that of the Japanese four-striped rat snake (E quadrivirgata, 2n = 36) Six pairs of the lizard macrochromosomes were homologous to eight pairs of the snake macrochromosomes The lizard chromosomes 1, 2, 4, and 6 corresponded to the snake chromosomes 1, 2, 3, and Z, respectively LRE3p and LRE3q showed the homology with EQU5 and EQU4, respectively, and LRE5p and LRE5q corresponded to EQU7 and EQU6, respectively These results suggest that the genetic linkages have been highly conserved between the two species and that their karyotypic difference might be caused by the telomere-to-telomere fusion events followed by inactivation of one of two centromeres on the derived dicentric chromosomes in the lineage of L reevesii rubritaeniata or the centric fission events of the bi-armed macrochromosomes and subsequent centromere repositioning in the lineage of E quadrivirgata The homology with L reevesii rubritaeniata microchromosomes were also identified in the distal regions of EQU1p and 1q, indicating the occurrence of telomere-to-telomere fusions of microchromosomes to the p and q arms of EQU1

Karyological characterization of the butterfly lizard (Leiolepis reevesii rubritaeniata, Agamidae, Squamata) by molecular cytogenetic approach.

Abstract: Karyological characterization of the butterfly lizard (Leiolepis reevesii rubritaeniata) was performed by conventional Giemsa staining, Ag-NOR banding, FISH with the 18S-28S and 5S

Improved Tryptophan Content in Maize with Opaque-2 gene Using Marker Assisted Selection (MAS) in Backcross and Selfing Generations

Abstract: The low nutritive value of the maize endosperm protein is genetically controlled. However, quality protein maize (QPM) which is available today contains the opaque-2 gene (o2o2) for double tryptophan content in the endosperm along with numerous modifiers for kernel vitreousness. The objectives of this study were: 1) to convert normal inbred lines to QPM inbred lines by the backcross method and marker-assisted selection (MAS) of the opaque-2 gene and 2) to estimate the combining ability of QPM inbred lines for yield and some agronomic characters. Crosses were made between normal maize and QPM as female and male parents, respectively. These were backcrossed to the recurrent parent. By the marker phi057, it was shown that all F1 were heterozygous (O2o2) while the BC1F1 progenies of Agron20 · Pop65C6-46 and Agron29 · Pop65C6-55 had 1:1 ratio of homozygous dominant (O2O2) to heterozygous (O2o2). The heterozygous offspring were self-pollinated to produce the BC1S1. By the marker of phi057 again, homozygous recessive (o2o2) plants were identified in one and six from the crosses of Agron20 · Pop65C6-46 and Agron29 · Pop65C6-55, respectively. The protein content in the endosperm of these seven lines ranged from 7.35 to 7.72% and the tryptophan content in the protein ranged from 0.70 to 0.84% which was in the range known for opaque-2 maize (0.80%), twice more than in normal maize (0.41%). The diallel cross of BC1S2 lines was made by Griffing’s Method 4 (fixed effect) and 21 F1-hybrids were obtained. The best test hybrid yielded 7.67 t ha 1 , which was close to the commercial single cross hybrid (KSX4452; 8.35 t ha -1 ). One line (P1) had the best combination of general combining ability effects for grain yield; a second line (P6) was almost equal. Both were

Detection of specific chromosome reduction in rice somatic hybrids with the A, B, and C genomes by multi-color genomic in situ hybridization.

Abstract: A multi-color genomic in situ hybridization (McGISH) method has been developed. Three different rice genomes, A, B and C, involved in rice somatic hybrids were distinguished using three different fluorescent signals. All the rice chromosomes from the different genomes could be identified by different fluorescent colors, and the distribution of each genome in the nucleus was clearly visualized under a fluorescence microscope. The relationship between chromosomal constitution and morphological variations observed in the somatic hybrids, and the utility of McGISH, are discussed based on the results currently obtained.

Food colorants: Challenges, opportunities and current desires of agro-industries to ensure consumer expectations and regulatory practices

Abstract: Background Worldwide consumers seek most delightful and appealing foodstuffs, at the same time they require safer, more nutritious and healthier products. Color is one of the most important organoleptic attributes that directly affects consumers' acceptance and food selection. Scope and approach The present report aims to provide an extensive approach to the field of food (natural/synthetic) colorants, namely those who are currently allowed with established acceptable daily intake (ADI). It also describes the biotechnological and industrial techniques that have been used to optimize food attractiveness, shelf life and color stability, as well as the general trends and future perspectives of food science and technology in the topic of food colorants. Key findings and conclusions Synthetic food colorants were largely used, but have been progressively substituted by those obtained from natural origins. Numerous side effects and toxicity, at both medium and long-terms, allergic reactions, behavioral and neurocognitive effects have been related with their use. Otherwise, naturally-derived food colorants seem to provide high quality, efficiency and organoleptic properties, and also play a contributive role as health promoters. Anthocyanins, carotenoids, phenolic compounds, beet derivatives, annatto and some curcuminoids are among the most commonly used, while strict regulatory practices have been applied looking for food quality assurance.

Comparative sex chromosome genomics in snakes: differentiation, evolutionary strata, and lack of global dosage compensation.

Abstract: Snakes exhibit genetic sex determination, with female heterogametic sex chromosomes (ZZ males, ZW females). Extensive cytogenetic work has suggested that the level of sex chromosome heteromorphism varies among species, with Boidae having entirely homomorphic sex chromosomes, Viperidae having completely heteromorphic sex chromosomes, and Colubridae showing partial differentiation. Here, we take a genomic approach to compare sex chromosome differentiation in these three snake families. We identify homomorphic sex chromosomes in boas (Boidae), but completely heteromorphic sex chromosomes in both garter snakes (Colubridae) and pygmy rattlesnake (Viperidae). Detection of W-linked gametologs enables us to establish the presence of evolutionary strata on garter and pygmy rattlesnake sex chromosomes where recombination was abolished at different time points. Sequence analysis shows that all strata are shared between pygmy rattlesnake and garter snake, i.e., recombination was abolished between the sex chromosomes before the two lineages diverged. The sex-biased transmission of the Z and its hemizygosity in females can impact patterns of molecular evolution, and we show that rates of evolution for Z-linked genes are increased relative to their pseudoautosomal homologs, both at synonymous and amino acid sites (even after controlling for mutational biases). This demonstrates that mutation rates are male-biased in snakes (male-driven evolution), but also supports faster-Z evolution due to differential selective effects on the Z. Finally, we perform a transcriptome analysis in boa and pygmy rattlesnake to establish baseline levels of sex-biased expression in homomorphic sex chromosomes, and show that heteromorphic ZW chromosomes in rattlesnakes lack chromosome-wide dosage compensation. Our study provides the first full scale overview of the evolution of snake sex chromosomes at the genomic level, thus greatly expanding our knowledge of reptilian and vertebrate sex chromosomes evolution.

Transcriptomic analysis of the oleaginous microalga Neochloris oleoabundans reveals metabolic insights into triacylglyceride accumulation

Abstract: Connecticut Center for Advanced Technology (Fuel Diversification Grant, by the National Science Foundation Grant #0854322)

What Is There in Seeds? Vertically Transmitted Endophytic Resources for Sustainable Improvement in Plant Growth

Abstract: Phytobeneficial microbes, particularly endophytes, such as fungi and bacteria, are concomitant partners of plants throughout its developmental stages, including seed germination, root and stem growth, and fruiting. Endophytic microbes have been identified in plants that grow in a wide array of habitats; however, seed-borne endophytic microbes have not been fully explored yet. Seed-borne endophytes are of great interest because of their vertical transmission; their potential to produce various phytohormones, enzymes, antimicrobial compounds, and other secondary metabolites; and improve plant biomass and yield under biotic and abiotic stresses. This review addresses the current knowledge on endophytes, their ability to produce metabolites, and their influence on plant growth and stress mitigation.

Sex chromosome evolution in lizards: independent origins and rapid transitions

Abstract: Reptiles epitomize the variability of reproductive and sex determining modes and mechanisms among amniotes. These modes include gonochorism (separate sexes) and parthenogenesis, oviparity, viviparity, and ovoviviparity, genotypic sex determination (GSD) with male (XX/XY) and female (ZZ/ZW) heterogamety and temperature-dependent sex determination (TSD). Lizards (order Squamata, suborder Sauria) are particularly fascinating because the distribution of sex-determining mechanisms shows no clear phylogenetic segregation. This implies that there have been multiple transitions between TSD and GSD, and between XY and ZW sex chromosome systems. Approximately 1,000 species of lizards have been karyotyped and among those, fewer than 200 species have sex chromosomes, yet they display remarkable diversity in morphology and degree of degeneration. The high diversity of sex chromosomes as well as the presence of species with TSD, imply multiple and independent origins of sex chromosomes, and suggest that the mechanisms of sex determination are extremely labile in lizards. In this paper, we review the current state of knowledge of sex chromosomes in lizards and the distribution of sex determining mechanisms and sex chromosome forms within and among families. We establish for the first time an association between the occurrence of female heterogamety and TSD within lizard families, and propose mechanisms by which female heterogamety and TSD may have co-evolved. We suggest that lizard sex determination may be much more the result of an interplay between sex chromosomes and temperature than previously thought, such that the sex determination mode is influenced by the nature of heterogamety as well as temperature sensitivity and the stage of sex chromosome degeneration.