AGHR polymorphism and its associations with carcass traits in Harrwoo cattle

The growth hormone receptor (GHR) is a membrane transmitter for the growth hormone signal transduction pathway that regulates various metabolic activities, including cell growth and expressions of cytokine genes. The presence or absence of a genetic polymorphism for the LINE-1 retroposon in the PI promoter, which specifically regulates theGHR gene expression in the liver, was screened by a novel detection method and examined for its relationships with carcass traits in Hanwoo cattle. Han woo cattle had taurine type LINE-1 present (alleleI) as well as incidine type LINE-1 absent (alleleA) promoter sequences. Three genotypes,I/I, I/A andA/A, showed frequencies of 49.1, 36.7 and 14.2%, respectively. The effects of allele A were significant on mean differences for final weight, eye muscle area, marbling score and fat color (p<0.05), but not for carcass weight, backfat thickness, final meat quality grade or meat color (p>0.05). Most 30-month old Hanwoo steers bearing the LINE-1 absent promoter had whiter fat color, heavier live weight and higher marbling score, reflecting intramuscular fat deposition inM. longissimus dorsi, compared to animals bearing a LINE-1 present promoter. This suggests that aGHR polymorphism could be a potential genetic marker for improving beef production of Hanwoo cattle.     

ITS2 ribosomal DNA sequence variation of the bumblebee,Bombus ardens (hymenoptera: Apidae)

The bumblebee species,Bombus, is an invaluable natural resource for greenhouse pollination. Low levels of genetic variation ofBombus ardens have been reported in a previous mitochondrial (mt) gene study. In this study, we sequenced the complete internal transcribed spacer 2 (ITS2) of the nuclear rDNA obtained from 100B. ardens individuals collected from several Korean localities, in an effort to assess its usefulness in characterizing the genetic diversity and relationships among populations of B. ardens. The ITS2 sequences ofB. ardens were shown to be longest among known insects, ranging in size from 1,971–1,984 bp. The sequences harbor four duplicated repeats-≈27 bp repeats, ≈20 bp repeats, ≈33 bp repeats, and ≈34 bp repeats-which have never before been reported in other insect ITS2 rDNA. The maximum sequence divergence of 1.01% among 96 sequence types confirmed the applicability of this molecule to the study of intraspecific variation, revealing higher sequence variation as compared to the previously studied mt COI gene. Overall, a very high per generation migration ratio (Nm = 5.83 ≈ infinite) and a very low level of genetic fixation (FST =0 –0.08) were noted to exist among populations ofB. ardens. The high estimation of gene flow among most populations-in particular, between the remote island Ulleungdo and several inland populations-suggest that historical events may be more responsible for the contemporary population structure of B. ardens. The finding of the lowest genetic diversity (π) in the population on Ulleungdo Island (π = 0.007434) may be reflective of a relatively small population size and the geographical isolation of the population as compared with other inland populations.     

Insect ornithine decarboxylase (ODC) complements <Emphasis Type="Italic">SPE1</Emphasis> knock-out of yeast <Emphasis Type="Italic">Saccharomyces cerevisiae</Emphasis>

Ornithine decarboxylase (ODC) is a rate-limiting enzyme in the biosynthesis of polyamines, which are essential for cell growth, differentiation, and proliferation. This report presents the characterization of an ODC-encoding cDNA (SlitODC) isolated from a moth species, the tobacco cutworm, Spodoptera litura (Lepidoptera); its expression in a polyamine-deficient strain of yeast, S. cerevisiae; and the recovery in polyamine levels and proliferation rate with the introduction of the insect enzyme. SlitODC encodes 448 amino acid residues, 4 amino acids longer than B. Mori ODC that has 71% identity, and has a longer C-terminus, consistent with B. mori ODC, than the reported dipteran enzymes. The null mutant yeast strain in the ODC gene, SPE1, showed remarkably depleted polyamine levels; in putrescine, spermidine, and spermine, the levels were > 7, > 1, and > 4%, respectively, of the levels in the wild-type strain. This consequently caused a significant arrest in cell proliferation of > 4% of the wild-type strain in polyaminefree media. The transformed strain, with the substituted SlitODC for the deleted endogenous ODC, grew and proliferated rapidly at even a higher rate than the wild-type strain. Furthermore, its polyamine content was significantly higher than even that in the wild-type strain as well as the spe1-null mutant, particularly with a very continuously enhanced putrescine level, reflecting no inhibition mechanism operating in the putrescine synthesis step by any corresponding insect ODC antizymes to SlitODC in this yeast system.     

Complete nucleotide sequence and organization of the mitogenome of the red-spotted apollo butterfly, Parnassius bremeri (Lepidoptera: Papilionidae) and comparison with other lepidopteran insects

The 15,389-bp long complete mitogenome of the endangered red-spotted apollo butterfly, Parnassius bremeri (Lepidoptera: Papilionidae) was determined in this study. The start codon for the COI gene in insects has been extensively discussed, and has long remained a matter of some controversy. Herein, we propose that the CGA (arginine) sequence functions as the start codon for the COI gene in lepidopteran insects, on the basis of complete mitogenome sequences of lepidopteran insects, including P. bremeri, as well as additional sequences of the COI start region from a diverse taxonomic range of lepidopteran species (a total of 53 species from 15 families). In our extensive search for a tRNA-like structure in the A+T-rich region, one tRNA^Trp-like sequence and one tRNA^Leu (UUR)-like sequence were detected in the P. bremeri A+T-rich region, and one or more tRNA-like structures were detected in the A+T-rich region of the majority of other sequenced lepidopteran insects, thereby indicating that such features occur frequently in the lepidopteran mitogenomes. Phylogenetic analysis using the concatenated 13 amino acid sequences and nucleotide sequences of PCGs of the four macrolepidopteran superfamilies together with the Tortricoidea and Pyraloidea resulted in the successful recovery of a monophyly of Papilionoidea and a monophyly of Bombycoidea. However, the Geometroidea were unexpectedly identified as a sister group of the Bombycoidea, rather than the Papilionoidea.