Tunicamycin-resistant mutants and chromosomal locations of mutational sites in Bacillus subtilis.

The types of tunicamycin-resistant mutants of Bacillus subtilis were analyzed, and their mutational sites on the chromosome were mapped. A type 1 mutation that simultaneously expressed hyperproductivity of extracellular alpha-amylase was located close to amy E. Type 2 mutations were near aroI.     

Mass spectrometry of trimethylsilyl derivatives of gibberellin glucosides and glucosyl esters

The mass spectra of trimethylsilyl ethers of six gibberellin-β-d-glucopyranosyl ethers and five gibberellin-β-d-glucopyranosyl esters are discussed. The fragmentation patterns are shown to be affected by the structural variations of the aglycones.     

Development and characterization of 21 polymorphic microsatellite loci in the aphidophagous gall midge, <Emphasis Type="Italic">Aphidoletes aphidimyza</Emphasis> (Diptera: Cecidomyiidae)

We have developed and characterized 21 microsatellite markers in the aphidophagous gall midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). All 21 loci tested were polymorphic: the number of alleles ranged from 2 to 17. Allelic richness and observed heterozygosities were higher in females than in males. Several loci had no heterozygosity in males, suggesting that the loci were located on sex chromosomes or E-chromosomes, common to cecidomyiids. The high polymorphism detected in this study suggests the markers will be of value in analyzing genetic structure of field populations.     

Effects of remnant primary forests on ant and dung beetle species diversity in a secondary forest in Sarawak, Malaysia

Tropical landscape structures have been transformed into mosaic structures consisting of small patches of primary and secondary forests, and areas of other land use. Diversity of insect assemblages is often higher in primary forests than in surrounding secondary forests. However, little is known about how the primary forests affect diversity in surrounding secondary forests in a landscape. In Sarawak, Malaysia, the typical landscape in areas from which lowland tropical rainforests had originally spread consists mainly of primary and secondary forests, with small areas of cultivation. In this study, we examined how the proportion of remnant primary forests in a landscape affects species diversity and species composition of ants and dung beetles in Macaranga-dominated secondary forests. The proportions were quantified based on remote-sensing data at various spatial scales, ranging from 100- to 5,000-m radius from each of the target forests. We found that the proportions of remnant primary forests within a 100-m radius had a significant positive effect on ant species diversity, and those within 100-, 300-, and 500-m radii significantly affected species compositions. However, the proportions of remnant primary forests had no significant relationship with dung beetle diversity, while those within 100- and 1,000-m radii had significant effects on species composition. The different responses to the remnant primary forests are likely to be related to differences in the movement and dispersal traits between the two taxa.     

Rapid establishment of introgression lines using cytoplasmic male sterility and a restorer gene in Oryza sativa cv. Nipponbare

Quantitative trait locus (QTL) analyses have greatly enhanced our understanding of complex traits in rice (Oryza sativa). In parallel, the development of introgression lines has provided a powerful tool for elucidation of complicated genetic networks and identification of QTL. We recently developed a biotron breeding system that allows rapid indoor cultivation of rice plants. The system, however, has two relatively weak points in its application to marker-assisted breeding in rice: first, variation in generation times among cultivars; second, the low number of seeds produced by crosses. To compensate for these weaknesses, we propose utilizing cytoplasmic male sterility (CMS) and restorer (Rf) lines with a cv. Nipponbare genetic background. Through use of the Nipponbare genetic background, rice generation times of 2 months can be achieved regardless of any differences in the genetic background of the donor rice plant. This CMS–Rf system confers a high yield of hybrid seeds, avoids the need for emasculation and precludes accidental crosses. Our results demonstrate that this new methodology can markedly accelerate many different aspects of rice research, especially in functional genomics. The combination of biotron breeding system, early flowering habit and CMS will be of great value for screening candidate genes associated with QTL and for introducing useful QTL into elite cultivars.     

A Reduction in Age-Enhanced Gluconeogenesis Extends Lifespan

The regulation of energy metabolism, such as calorie restriction (CR), is a major determinant of cellular longevity. Although augmented gluconeogenesis is known to occur in aged yeast cells, the role of enhanced gluconeogenesis in aged cells remains undefined. Here, we show that age-enhanced gluconeogenesis is suppressed by the deletion of the tdh2 gene, which encodes glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a protein that is involved in both glycolysis and gluconeogenesis in yeast cells. The deletion of TDH2 restores the chronological lifespan of cells with deletions of both the HST3 and HST4 genes, which encode yeast sirtuins, and represses the activation of gluconeogenesis. Furthermore, the tdh2 gene deletion can extend the replicative lifespan in a CR pathway-dependent manner. These findings demonstrate that the repression of enhanced gluconeogenesis effectively extends the cellular lifespan.     

Expression of Epidermal Growth Factor Receptor Detected by Cetuximab Indicates Its Efficacy to Inhibit In Vitro and In Vivo Proliferation of Colorectal Cancer Cells

Cetuximab is a chimeric mouse–human monoclonal antibody that targets the human epidermal growth factor receptor (EGFR). However, EGFR expression determined by immunohistochemistry does not predict clinical outcomes of colorectal cancer (CRC) patients treated with cetuximab. Therefore, we evaluated the correlation between EGFR levels detected by cetuximab and drug sensitivities of CRC cell lines (Caco-2, WiDR, SW480, and HCT116) and the A431 epidermoid carcinoma cell line. We used flow cytometry (FCM) to detect EGFR-binding of biotinylated cetuximab on the cell surface. Subcloned cell lines showing the highest and lowest EGFR expression levels were chosen for further study. Cytotoxic assays were used to determine differential responses to cetuximab. Xenograft models treated with cetuximab intraperitoneally to assess sensitivity to cetuximab. Strong responses to cetuximab were specifically exhibited by subcloned cells with high EGFR expression levels. Furthermore, cetuximab inhibited the growth of tumors in xenograft models with high or low EGFR expression levels by 35% and 10%–20%, respectively. We conclude that detection of EGFR expression by cetuximab promises to provide a novel, sensitive, and specific method for predicting the sensitivity of CRC to cetuximab.     

Cell size dependence of orientational order of uniaxial liquid crystals in flat slit

In order to investigate the ordered structure of nematic liquid crystal molecules confined in a nanoslit, we carried out a classical molecular dynamics simulation of uniaxial prolate Gay–Berne particles in a flat, structureless slit at several temperatures. When the slit gap is so small that the system is not assumed as the bulk, particles in the slit possess orientationally ordered structures different from ones in the bulk. The weak spacial orientational correlation existed when the temperature corresponded to the isotropic phase in the bulk system. The first order isotropic–nematic phase transition was not clearly observed and the transitional phenomenon of the creation and annihilation of the uniaxial domains were observed. These results revealed that the ordered structure depends on the number of particles, in other words, cell size, and that the system with 100,000 or more particles gives reasonable results of an infinitely wide slit. The number of particles is converted into up to 220 particles of the length of the base.     

Discovery of a disused desaturase gene from the pheromone gland of the moth Ascotis selenaria, which secretes an epoxyalkenyl sex pheromone

Female Ascotis selenaria (Geometridae) moths use 3,4-epoxy-(Z,Z)-6,9-nonadecadiene, which is synthesized from linolenic acid, as the main component of their sex pheromone. While the use of dietary linolenic or linoleic fatty acid derivatives as sex pheromone components has been observed in moth species belonging to a few families including Geometridae, the majority of moths use derivatives of a common saturated fatty acid, palmitic acid, as their sex pheromone components. We attempted to gain insight into the differentiation of pheromone biosynthetic pathways in geometrids by analyzing the desaturase genes expressed in the pheromone gland of A. selenaria. We demonstrated that a Δ11-desaturase-like gene (Asdesat1) was specifically expressed in the pheromone gland of A. selenaria in spite of the absence of a desaturation step in the pheromone biosynthetic pathway in this species. Further analysis revealed that the presumed transmembrane domains were degenerated in Asdesat1. Phylogenetic analysis demonstrated that Asdesat1 anciently diverged from the lineage of Δ11-desaturases, which are currently widely used in the biosynthesis of sex pheromones by moths. These results suggest that an ancestral Δ11-desaturase became dysfunctional in A. selenaria after a shift in pheromone biosynthetic pathways.