The biological significance of methionine sulfoxide stereochemistry

Methionine can be oxidized by reactive oxygen species to a mixture of two diastereomers, methionine-S-sulfoxide and methionine-R-sulfoxide. Both free amino acid and protein-based forms of methionine-S-sulfoxide are stereospecifically reduced by MsrA, whereas the reduction of methionine-R-sulfoxide requires two enzymes, MsrB and fRMsr, which act on its protein-based and free amino acid forms, respectively. However, mammals lack fRMsr and are characterized by deficiency in the reduction of free methionine-R-sulfoxide. The biological significance of such biased reduction of methionine sulfoxide has not been fully explored. MsrA and MsrB activities decrease during aging, leading to accumulation of protein-based and free amino acid forms of methionine sulfoxide. Since methionine is an indispensible amino acid in human nutrition and a key metabolite in sulfur, methylation, and transsulfuration pathways, the consequences of accumulation of its oxidized forms require further studies. Finally, in addition to methionine, methylsulfinyl groups are present in various drugs and natural compounds, and their differential reduction by Msrs may have important therapeutic implications.     

Molecular identification of AFLP fragments associated with elytra color variation of the Asian ladybird beetle,Harmonia axyridis (Coleoptera: Coccinellidae)

The Asian ladybird beetle, Harmonia axyridis shows polymorphism in elytra color patterns. However, it is uncertain whether these color patterns are regulated by genetic factors. This investigation used amplified fragment length polymorphism (AFLP) analysis to determine any genetic causes of the variability of color patterns. Using four individuals of each group, AFLP analysis produced 37 polymorphic bands. Among several polymorphic bands, six AFLP markers were associated with elytra color patterns after further analysis using six additional individuals of each group. These polymorphic sites were sequenced but did not match DNA sequence data deposited in GenBank. Based on the color-associated AFLP markers, SCAR primers were designed for PCR amplification of genomic DNA. These primers (SCAR 12 and SCAR 44) were used to analyze color-associated loci and/or alleles of H. axyridis DNA. SCAR 12 primers designed from a Spectabilis type-specific fragment (AFLP 12) amplified a specific band of 530 bp in four Spectabilis individuals, but not in the insects with other color patterns.     

Complete mitochondrial genome of the nerippe fritillary butterfly, Argynnis nerippe (Lepidoptera: Nymphalidae)

The complete mitochondrial genome sequence of the nerippe fritillary butterfly, Argynnis nerippe, which is listed as an endangered species in Korea, is described with an emphasis on the A+T-rich region. The 15,140-bp long circular molecule consisted of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and 1 control region, known in insect as the A+T-rich region, as found in typical metazoans. The 329-bp long A+T-rich region located between srRNA and tRNA(Met) possessed the highest A/T content (95.7%) than any other region of the genome. Along with the several conserved sequences found typically in the lepidopteran insects the genome contained one tRNA(Met)-like and tRNA(Leu)(UUR)-like sequence in the A+T-rich region.     

Molecular cloning and expression patterns of FK506‐binding protein 12, an immunophilin from the cabbage butterfly,Pieris rapae

FK506‐binding protein (FK506BP) class belonging to immunophilin protein family has been known to play key roles in modulating T‐cell activation, regulation of cell cycle and protein folding. However, little is known about the involvement of FK506BP during viral pathogenesis in insect host. In this study, an attempt has been made to focus on the involvement of FK506BP in antiviral innate immunity, by cloning the full‐length cDNA of FK506BP12 (PrFK506BP12) from the cabbage butterfly, Pieris rapae. It comprised of 532 bp (excluding poly‐A tail) with a longest open reading frame (ORF) of 327 bp encoding 108 amino acids. In silico analysis of PrFK506BP12 ORF revealed a highly conserved FK506‐binding domain (FKBD). As expected, it showed high homology to other FK506BPs identified from Bombyx mori (92%), Manduca sexta (91%), Suberites domuncula (82%), Tribolium castaneum (81%) and Aedes aegypti (74%) . Expression of PrFK506BP12 was observed during developmental stages of P. rapae, but was pronounced in late pupal and adult stage. In addition, spatial expression pattern analysis indicated its high expression in the head and fat body. Furthermore, PrFK506BP12 mRNA was induced 12 h after LTA, Poly I:C treatment and 3h after Pieris rapae granulovirus (PrGV) treatment in carcass. It suggests that PrFK506BP12 appears to be involved in immune responses and also play an important role in the fat body, although it remains to be clarified about their precise role in response to granulovirus.     

Development of a risk scoring system for patients with papillary thyroid cancer

As the importance of personalized therapeutics in aggressive papillary thyroid cancer (PTC) increases, accurate risk stratification is required. To develop a novel prognostic scoring system for patients with PTC (n = 455), we used mRNA expression and clinical data from The Cancer Genome Atlas. We performed variable selection using Network‐Regularized high‐dimensional Cox‐regression with gene network from pathway databases. The risk score was calculated using a linear combination of regression coefficients and mRNA expressions. The risk score and clinical variables were assessed by several survival analyses. The risk score showed high discriminatory power for the prediction of event‐free survival as well as the presence of metastasis. In multivariate analysis, the risk score and presence of metastasis were significant risk factors among the clinical variables that were examined together. In the current study, we developed a risk scoring system that will help to identify suitable therapeutic options for PTC.