Complete sequence and analysis of the plastid genome of the unicellular red alga Cyanidioschyzon merolae.

The complete nucleotide sequence of the plastid genome of the unicellular primitive red alga Cyanidioschyzon merolae 10D (Cyanidiophyceae) was determined. The genome is a circular DNA composed of 149,987 bp with no inverted repeats. The G + C content of this plastid genome is 37.6%. The C. merolae plastid genome contains 243 genes, which are distributed on both strands and consist of 36 RNA genes (3 rRNAs, 31 tRNAs, tmRNA, and a ribonuclease P RNA component) and 207 protein genes, including unidentified open reading frames. The striking feature of this genome is the high degree of gene compaction; it has very short intergenic distances (approximately 40% of the protein genes were overlapped) and no genes have introns. This genome encodes several genes that are rarely found in other plastid genomes. A gene encoding a subunit of sulfate transporter (cysW) is the first to be identified in a plastid genome. The cysT and cysW genes are located in the C. merolae plastid genome in series, and they probably function together with other nuclear-encoded components of the sulfate transport system. Our phylogenetic results suggest that the Cyanidiophyceae, including C. merolae, are a basal clade within the red lineage plastids.     

Some characteristics of three groups in Flammulina velutipes classified by analysis of esterase isozymes

 Analysis of isozymes was carried out against wild and cultivated commercial stocks of Flammulina velutipes to analyze their genetic differences. Esterase isozymes from F. velutipes showed many bands and variations among the different stocks on the gel. The stocks of F. velutipes in Japan were largely classified into three groups (tentatively named groups A, B, and C) according to the cluster analysis of esterase isozymes. Some characteristics of the three groups were examined. Group C was characterized by a larger spore size, slower spawn running, and a paler pileus color than groups A and B. Furthermore, group B showed a smaller spore size, slower spawn running, and paler pileus color than group A. Received: August 27, 2002 / Accepted: October 10, 2002 Correspondence to:K. Nishizawa     

Interaction between Nbp35 and Cfd1 Proteins of Cytosolic Fe-S Cluster Assembly Reveals a Stable Complex Formation in Entamoeba histolytica

Iron-Sulfur (Fe-S) proteins are involved in many biological functions such as electron transport, photosynthesis, regulation of gene expression and enzymatic activities. Biosynthesis and transfer of Fe-S clusters depend on Fe-S clusters assembly processes such as ISC, SUF, NIF, and CIA systems. Unlike other eukaryotes which possess ISC and CIA systems, amitochondriate Entamoeba histolytica has retained NIF & CIA systems for Fe-S cluster assembly in the cytosol. In the present study, we have elucidated interaction between two proteins of E. histolytica CIA system, Cytosolic Fe-S cluster deficient 1 (Cfd1) protein and Nucleotide binding protein 35 (Nbp35). In-silico analysis showed that structural regions ranging from amino acid residues (P33-K35, G131-V135 and I147-E151) of Nbp35 and (G5-V6, M34-D39 and G46-A52) of Cfd1 are involved in the formation of protein-protein complex. Furthermore, Molecular dynamic (MD) simulations study suggested that hydrophobic forces surpass over hydrophilic forces between Nbp35 and Cfd1 and Van-der-Waal interaction plays crucial role in the formation of stable complex. Both proteins were separately cloned, expressed as recombinant fusion proteins in E. coli and purified to homogeneity by affinity column chromatography. Physical interaction between Nbp35 and Cfd1 proteins was confirmed in vitro by co-purification of recombinant Nbp35 with thrombin digested Cfd1 and in vivo by pull down assay and immunoprecipitation. The insilico, in vitro as well as in vivo results prove a stable interaction between these two proteins, supporting the possibility of its involvement in Fe-S cluster transfer to target apo-proteins through CIA machinery in E. histolytica. Our study indicates that initial synthesis of a Fe-S precursor in mitochondria is not necessary for the formation of Cfd1-Nbp35 complex. Thus, Cfd1 and Nbp35 with the help of cytosolic NifS and NifU proteins can participate in the maturation of non-mitosomal Fe-S proteins without any apparent assistance of mitosomes.     

Precursors of Dancing and Singing to Music in Three- to Four-Months-Old Infants

Dancing and singing to music involve auditory-motor coordination and have been essential to our human culture since ancient times. Although scholars have been trying to understand the evolutionary and developmental origin of music, early human developmental manifestations of auditory-motor interactions in music have not been fully investigated. Here we report limb movements and vocalizations in three- to four-months-old infants while they listened to music and were in silence. In the group analysis, we found no significant increase in the amount of movement or in the relative power spectrum density around the musical tempo in the music condition compared to the silent condition. Intriguingly, however, there were two infants who demonstrated striking increases in the rhythmic movements via kicking or arm-waving around the musical tempo during listening to music. Monte-Carlo statistics with phase-randomized surrogate data revealed that the limb movements of these individuals were significantly synchronized to the musical beat. Moreover, we found a clear increase in the formant variability of vocalizations in the group during music perception. These results suggest that infants at this age are already primed with their bodies to interact with music via limb movements and vocalizations.     

Essentializing Dilemma and Multiculturalist Pedagogy: An Ethnographic Study of Japanese Children in a U.S. School

This article examines some Japanese children's experiences at a U.S. elementary school, as well as their teachers' pedagogical responses. Two discourses of difference—"individual difference" and "social/cultural difference"—were used in the school in somewhat dichotomous ways, and the combination worked against those children who had difficulty adjusting. A third pedagogic discourse of difference needs to be constructed to aid teachersfacing essentializing dilemmas.     

Isolation of endo A cDNA from mouse 8-cell stage embryos

To analyse the species of genes expressed in a cleavage stage mouse embryo, we have constructed a cDNA library containing 3.0 x 10(5) independent clones from about 2 x 10(3) embryos at the 8-cell stage of development. Endo A cDNA prepared from parietal yolk sac endoderm like PYS-2 cells was used to screen the library. Southern blot analyses using the endo A sequence as a probe and restriction mapping analyses revealed that four independent recombinants had been inserted endo A sequence. Sequencing data of these clones showed that endo A mRNA present in the 8-cell stage embryo is identical to that of parietal yolk sac endoderm cells.     

Detection of H-2K mRNA in mouse 8-cell embryo by cDNA cloning

Mouse MHC class I gene expression in 8-cell embryo was examined by cDNA cloning. We constructed a cDNA library from 8-cell embryos of ICR mice and isolated a class I cDNA from 3.0 x 10(5) phage clones of the library. Sequencing analysis of this clone revealed it to include the cDNA fragment extending from the exon 6 of the cytoplasmic portion to 3' untranslated region 1 of H-2K gene. Qa, Tla or other embryonic class I cDNA have not been isolated in the library.     

Termite queens have disproportionately more DNA in their fat body cells: reproductive division of labor and endoreduplication

Increases in DNA content caused by endoreduplication are widely observed in the metabolically active tissues of plants and animals. During egg production, insect females synthesize very large amounts of vitellogenin in their fat bodies, and female fat bodies of some insects become polyploid to accelerate vitellogenin production. Social insects have developed reproductive division of labor, wherein queens lay most of the eggs while other individuals have reduced fertility and undertake tasks required for maintaining the colony. Therefore, only queens are engaged in vitellogenin synthesis for egg production in social insects. Here, we show that termite queens have disproportionately more DNA in their fat body cells. Our DNA content analysis using flow cytometry demonstrated that more cells contained 4C‐DNA than 2C‐DNA in the fat bodies of Reticulitermes speratus queens. This high level of endoreduplication was not found in the fat body cells of other castes. This caste‐dependent doubling of DNA content in fat body cells suggests that termites exploit endoreduplication to boost egg production, in conjunction with the development of reproductive division of labor. This study highlights nuclear polyploidization as an adaptive strategy in social insects.