Effects of blood mercury accumulation on DNA methylation levels in the Khorat snail-eating turtle (Malayemys khoratensis).

Mercury (Hg) has adverse effects on humans and wildlife. Hg exposure can cause significant alterations in DNA methylation, an epigenetic modification that causes various illnesses. Hg accumulation in the blood of the Khorat snail-eating turtle (Malayemys khoratensis) from northeastern Thailand was previously reported. Thus, this study aimed to assess total mercury (THg) levels in M. khoratensis blood and to examine the impact of these concentrations on DNA methylation (5-methylcytosine, 5-mC) levels. We divided turtles based on morphological characteristics into two groups, normal and deformed, and then the levels of each variable in both groups were assessed. The deformed group presented higher mean THg concentration and DNA methylation levels compared to the normal group; however, the differences were not significant. Additionally, we found no correlation between DNA methylation levels and THg concentrations in both groups. This study is the first attempt to investigate the relationship between mercury accumulation and DNA methylation in the blood of deformed freshwater turtles.

Y chromosomal evidence on the origin of northern Thai people.

The Khon Mueang represent the major group of people present in today's northern Thailand. While linguistic and genetic data seem to support a shared ancestry between Khon Mueang and other Tai-Kadai speaking people, the possibility of an admixed origin with contribution from local Mon-Khmer population could not be ruled out. Previous studies conducted on northern Thai people did not provide a definitive answer and, in addition, have largely overlooked the distribution of paternal lineages in the area. In this work we aim to provide a comprehensive analysis of Y paternal lineages in northern Thailand and to explicitly model the origin of the Khon Mueang population. We obtained and analysed new Y chromosomal haplogroup data from more than 500 northern Thai individuals including Khon Mueang, Mon-Khmer and Tai-Kadai. We also explicitly simulated different demographic scenarios, developed to explain the Khon Mueang origin, employing an ABC simulation framework on both mitochondrial and Y microsatellites data. Our results highlighted a similar haplogroup composition of Khon Mueang and Tai-Kadai populations in northern Thailand, with shared high frequencies of haplogroups O-PK4, O-M117 and O-M111. Our ABC simulations also favoured a model in which the ancestors of modern Khon Mueang originated recently after a split from the other Tai-Kadai populations. Our different analyses concluded that the ancestors of Khon Mueang are likely to have originated from the same source of the other Tai-Kadai groups in southern China, with subsequent admixture events involving native Mon-Khmer speakers restricted to some specific populations.

Proteomic Analysis of Isogenic Rice Reveals Proteins Correlated with Aroma Compound Biosynthesis at Different Developmental Stages.

Fragrant rice has a potent flavor compound, 2-acetyl-1-pyrroline (2AP). A better understanding of the 2AP biosynthetic pathway is gained by proteomic analysis of two isogenic lines of Thai jasmine rice, Oryza sativa L. cv. Khao Dawk Mali 105, which differ only in the aromatic gene Os2AP. The protein profiles of two lines, from six growth stages, seedling to grain filling, had 41 identifiable protein spots. Four of these spots were betaine aldehyde dehydrogenase, a key enzyme responsible for 2AP production. This enzyme occurred in every growth stage of the non-aromatic rice line except smaller amount detected in the hard grain-filling stage of the aromatic line. Glyceraldehyde 3-phosphate dehydrogenase and aspartate aminotransferase, observed in the aromatic line, may involve in the metabolism of precursors for 2AP biosynthesis. In addition, glutamine synthetase and 1-cys peroxiredoxin A which function in ammonia reassimilation and hydrogen peroxide detoxification were unique in the aromatic line. However, proteins that correspond to photosynthesis and the nutrient reservoir were only detected in lower abundances. This possibly explains why the aroma rice grain weight is low. Our study proposed the possible role of these remarkable proteins which involved in 2AP biosynthesis in jasmine rice.

Evaluation of sample preparation methods from rice seeds and seedlings suitable for two-dimensional gel electrophoresis.

In a proteomic study, sample preparation is very important because it affects the quality of protein profiles on two-dimensional gel electrophoresis (2-DE). This study investigated the suitability of four protein extraction methods-direct lysis buffer extraction, trichloroacetic acid (TCA)/acetone precipitation, phenol extraction, and polyethylene glycol (PEG) fractionation-from rice seeds and seedlings (Oryza sativa L. ssp. indica cv. Khao Dawk Mali 105). The effectiveness of these methods was evaluated by the protein quantity and the 2-DE profiling quality. This included the number of protein spots, the consistency and uniqueness of protein spots, and their distribution in different ranges of pI and molecular weight (M r ). For protein quantity, the phenol and direct lysis extraction methods gave the highest protein yield in rice seeds and rice seedlings, respectively. However, in terms of the quality of 2-DE profiles, samples prepared by the TCA/acetone and phenol methods exhibited higher protein resolution and more spots than the protein profile derived from direct lysis extract. In addition, TCA/acetone method had the efficiency for high M r protein detection. PEG fractionation provided the best 2-DE pattern in terms of resolution, number of spots, minimal streaking, and reproducibility. Moreover, PEG fractionation was better for determining low M r basic proteins.

Computational design of peptide inhibitor based on modifications of proregion from Plutella xylostella midgut trypsin.

Many proteases are produced as zymogens bearing the N-terminal proregions acting both as intramolecular chaperones and as protease inhibitors. The latter role of the proregions as potent and specific inhibitors of their associated protease has been demonstrated in various peptidases and therefore has been targeted for alternative pest control. Here, we isolated amino acid sequence of Plutella xylostella midgut trypsin from the larvae of diamondback moth and tested in silico for its inhibitory activity toward propeptide models using computational modeling and docking. The propeptide models (AAAPGHR, AAAPGRR, AAAPGKR, AAPGHRI, APGHRIV, PGHRIVG, AAAAPGH, and AAAAAPG) were designed based on histidine-mutated and frame-shifted modifications of the 7-amino-acid proregion (AAAPGHR) of the Plutella xylostella trypsin. Among the eight peptides, AAAPGRR was found to give the best docking scores, showing a strong binding to the cognate enzyme. In addition, the obtained structure of trypsin-AAAPGRR complex was found to share a similar binding mode with a crystal structure of plant protease inhibitor complex. Our results may guide the experiment for the design of future peptide inhibitor with specificity and selectivity for the target enzyme.