Combining mapping of physiological quantitative trait loci and transcriptome for cold tolerance for counteracting male sterility induced by low temperatures during reproductive stage in rice

Male sterility induced by low temperatures (LTs) during the reproductive stage is a major constraint for temperate zone rice. To detect physiological quantitative trait loci (QTLs), we modeled genotypic variation in the physiological processes involved in low temperature spikelet sterility on the basis of anther length (AL), a proxy for microspore and pollen grain number per anther. The model accounted for 83% of the genotypic variation in potential AL at normal temperature and the ability to maintain AL at LT. We tested the model on 208 recombinant inbred lines of cold‐tolerant ‘Tohoku‐PL3’ (PL3) × cold‐sensitive ‘Akihikari’ (AH) for 2 years. QTLs for spikelet fertility (FRT) at LT were detected on chromosomes 5 (QTL for Cold Tolerance at Reproductive stage, qCTR5) and 12 (qCTR12). qCTR12 was annotated with the ability to maintain AL under LTs. qCTR5 was in a region shared with QTLs for culm length and heading date. Genome‐wide expression analysis showed 798 genes differentially expressed in the spikelets between the parents at LTs. Of these, 12 were near qCTR5 and 23 were near qCTR12. Gene expression analysis confirmed two candidate genes for qCTR5 (O‐methyltransferase ZRP4, Os05g0515600; beta‐1,3‐glucanase‐like protein, Os05g0535100) and one for qCTR12 (conserved hypothetical protein, Os12g0550600). Nucleotide polymorphisms (21 deletions, 2 insertions and 10 single nucleotide polymorphisms) in PL3 were found near the candidate conserved hypothetical protein (Os12g0550600) and upstream in PL3, but not in AH. Haplotype analysis revealed that this gene came from ‘Kuchum’. The combination of mapping physiological QTLs with gene expression analysis can be extended to identify other genes for abiotic stress response in cereals.     

Aureolysin of Staphylococcus warneri M accelerates its proteolytic cascade,and participates in biofilm formation

The aureolysin (Aur) gene of S. warneri M (aurWM) was cloned and sequenced. Analyses of the aurWM-inactivated mutant (S. warneri Mau) suggested that AurWM was probably associated with efficient processing of the PROM protease (homolog of V8/SspA serine protease), whereas considerable amount of mature-PROC protease (homolog of SspB cysteine protease) accumulated without AurWM. Additionally, AurWM appeared to affect biofilm formation in an uncertain suppressive way.     

Mutant analyses reveal different functions of fgfr1 in medaka and zebrafish despite conserved ligand-receptor relationships

Medaka (Oryzias latipes) is a small freshwater teleost that provides an excellent developmental genetic model complementary to zebrafish. Our recent mutagenesis screening using medaka identified headfish (hdf) which is characterized by the absence of trunk and tail structures with nearly normal head including the midbrain-hindbrain boundary (MHB). Positional-candidate cloning revealed that the hdf mutation causes a functionally null form of Fgfr1. The fgfr1hdf is thus the first fgf receptor mutant in fish. Although FGF signaling has been implicated in mesoderm induction, mesoderm is induced normally in the fgfr1hdf mutant, but subsequently, mutant embryos fail to maintain the mesoderm, leading to defects in mesoderm derivatives, especially in trunk and tail. Furthermore, we found that morpholino knockdown of medaka fgf8 resulted in a phenotype identical to the fgfr1hdf mutant, suggesting that like its mouse counterpart, Fgf8 is a major ligand for Fgfr1 in medaka early embryogenesis. Intriguingly, Fgf8 and Fgfr1 in zebrafish are also suggested to form a major ligand-receptor pair, but their function is much diverged, as the zebrafish fgfr1 morphant and zebrafish fgf8 mutant acerebellar (ace) only fail to develop the MHB, but develop nearly unaffected trunk and tail. These results provide evidence that teleost fish have evolved divergent functions of Fgf8-Fgfr1 while maintaining the ligand-receptor relationships. Comparative analysis using different fish is thus invaluable for shedding light on evolutionary diversification of gene function.     

First record of the invasive woodwasp,Urocerus albicornis (Hymenoptera: Siricidae), from a local forest in Japan

The woodwasp Urocerus albicornis (Fabricius, 1781) (Hymenoptera: Siricidae) is a forest pest native to North America and occasionally introduced into European countries. One of these invasive woodwasps was collected in a local forest in Nagano Prefecture, Central Japan. The collected individual was an adult female ovipositing on a log from a Japanese larch (Larix kaempferi (Lamb.) Carrière). Although several of these woodwasps have been found on imported logs in Japan, this is the first record of the alien woodwasp in a local forest within Japan and Asia. This finding indicates that a population of this invasive woodwasp may be established in Japanese forests.     

Metabolic activation of carcinogenic 1-nitropyrene by human cytochrome P450 1B1 in Salmonella typhimurium strain expressing an O-acetyltransferase in SOS/umu assay

Metabolic activation of 1-nitropyrene (1-NP) by human cytochrome P450 (P450) family 1 enzymes co-expressed with NADPH-cytochrome P450 reductase (NPR) in Escherichia coli membranes was investigated. 1-NP induced umu gene expression in Salmonella typhimurium TA1535/pSK1002 in the absence of any P450 system, but the activities were influenced by the levels of bacterial O-acetyltransferase (OAT) and nitroreductase. Metabolic activation of 1-NP by human P450 1B1/NPR membranes was observed and was influenced by the levels of OAT levels in tester strains. Metabolic activation of 1-NP (0.3microM) by P450 1B1 was 750 umu units/min/nmol P450 1B1 in an OAT-overexpressing strain NM2009. The metabolic activation of 1-NP (3-30microM) was similar (approximately 300 umu units/min/nmol P450 1B1) using TA1535/pSK1002 or OAT-deficient strain NM2000. P450 1B1 had the highest catalytic activities among P450 family 1 enzymes for the activation of 1-aminopyrene (1-AP) in the OAT-overexpressing strain NM2009, suggesting nitrenium ion formation via N-hydroxylation/O-acetylation. High-performance liquid chromatography (HPLC) analyses revealed the formation of 1-nitropyrene-6-ol and also 1-nitropyrene-3-ol, 1-nitropyrene-8-ol, and trans-4,5-dihydroxy-4,5-diol-1-nitropyrene from 1-NP (10microM), catalyzed by P450 1B1. These results indicate that 1-NP can be activated by human P450 1B1 to a genotoxic agent by nitroreduction/O-acetylation at low substrate concentrations and probably by epoxidation (independent of OAT) at high concentrations.     

Population structure and dynamics of an evergreen shade herb, Ainsliaea apiculata (Asteraceae), with special reference to herbivore effects

The population structure and dynamics of Ainsliaea apiculata, a forest understory evergreen herb widely distributed in Japan, was examined in a Chamaecyparis obtusa forest in Ibaraki Prefecture, central Japan (36°51N, 140°33E; 750 m a.s.l.). The mean population growth rate () calculated from the transition matrices for 4 years was 0.69 per year, predicting that the population size will decrease remarkably. There was a significant positive correlation between the survival of old leaves and the growth of new shoots in the following year. The shoots, especially new leaves, were damaged severely by herbivores (caterpillars of Leioptilus sp.). The survival rate of leaves formed in the previous spring to the next spring was remarkably low (41–54%). The growth of new shoots depended mainly on the reserves contained in old shoots, especially those in old leaves. New shoots of A. apiculata began to develop in spring, even though they were formed in autumn of the previous year. A defoliation experiment also showed that the removal of old shoots at the beginning of the growing season significantly inhibited the growth of new shoots. Damage to old shoots by herbivores severely influenced the growth and population dynamics of A. apiculata.     

Angiopoietin-3, a novel member of the angiopoietin family

A cDNA clone encoding angiopoietin-3 protein (Ang3), a novel member of the angiopoietin family, was identified. Ang3 cDNA was cloned from a human aorta cDNA library. Ang3 is a 503 amino acid protein having 45.1% and 44.7% identity with human angiopoietin-1 and human angiopoietin-2, respectively. Ang3 mRNA is expressed in lung and cultured human umbilical vein endothelial cells (HUVECs). Ang3 mRNA expression in HUVECs was slightly decreased by vascular endothelial cell growth factor treatment, suggesting that the regulation of Ang3 mRNA expression is different from that of Ang2.     

Management of the hairline using a local flap in total reconstruction for microtia

In cases of microtia with a low hairline, the manner in which hair is removed from the reconstructed auricle must be taken into consideration. This is one of the most common but difficult problems with reconstruction for microtia. The authors describe a new technique that uses a simple regional flap to resolve this problem. The hair-bearing skin in the estimated auricular region and its covering are removed using a local flap from the hairless mastoid region. This is done in the first stage of auricular reconstruction, the costal cartilage grafting is done in the second stage, and elevation of the auricle is done in the last stage. In 38 auricles of 36 patients who were treated from 1993 to 1995, eight auricles of eight patients were treated with this technique. In all cases, the hairless flap healed well, without vascular stasis or skin necrosis. In addition, no complications from using this technique occurred in the later stages of auricular reconstruction. With this technique, the skin of the flap provides a good texture and color match to the auricle. In addition, the skin of the flap has good elasticity for the cutaneous pocket for cartilage grafting. The harvested area of the flap can be hidden behind the reconstructed auricle. The authors initially wondered whether the marginal scar of the transposed flap's position in the auricle would be conspicuous. However, all of the scar became inconspicuous because it was positioned in the scaphoid fossa.