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Lysinibacillus sp. strain SGAir0095 was isolated from tropical air samples collected in Singapore, and its complete genome was sequenced with a hybrid strategy using single-molecule real-time sequencing and short reads. The genome consists of one chromosome of 4.14 Mbp and encompasses 3,885 protein-coding genes, 39 rRNAs, and 101 tRNAs.

Micrococcus luteus strain SGAir0127 was isolated from indoor air samples collected in Singapore. The assembly, based on single-molecule real-time sequencing reads, resulted in two contigs, one chromosomal contig with a length of 2.57 Mbp and one nonchromosomal contig of 8.68 kbp. The genome has a total of 2,564 genes.

Streptomyces sp. strain SGAir0924 was isolated from outdoor air collected in Singapore. Its genome was assembled using long reads generated by single-molecule real-time sequencing. The final assembly had one chromosome of 7.65 Mb and three plasmids with an average length of 142 kb. The genome contained 6,825 protein-coding genes, 68 tRNAs, and 18 rRNAs.

The complete genome sequence of Rhodococcus sp. strain SGAir0479 is presented here. This organism was isolated from an air sample collected in an indoor location in Singapore. The consensus assembly generated one chromosome of 4.86 Mb (G+C content of 69.8%) and one plasmid of 104,493 bp.

IntroductionAllergic sensitisation to fungi such asAspergillusare associated to poor clinical outcomes in asthma, bronchiectasis and cystic fibrosis; however, clinical relevance in COPD remains unclear.MethodsPatients with stable COPD (n=446) and nondiseased controls (n=51) were prospectively recruited across three countries (Singapore, Malaysia and Hong Kong) and screened against a comprehensive allergen panel including house dust mites, pollens, cockroach and fungi. For the first time, using a metagenomics approach, we assessed outdoor and indoor environmental allergen exposure in COPD. We identified key fungi in outdoor air and developed specific-IgE assays against the top culturable fungi, linking sensitisation responses to COPD outcomes. Indoor air and surface allergens were prospectively evaluated by metagenomics in the homes of 11 COPD patients and linked to clinical outcome.ResultsHigh frequencies of sensitisation to a broad range of allergens occur in COPD. Fungal sensitisation associates with frequent exacerbations, and unsupervised clustering reveals a “highly sensitised fungal predominant” subgroup demonstrating significant symptomatology, frequent exacerbations and poor lung function. Outdoor and indoor environments serve as important reservoirs of fungal allergen exposure in COPD and promote a sensitisation response to outdoor air fungi. Indoor (home) environments with high fungal allergens associate with greater COPD symptoms and poorer lung function, illustrating the importance of environmental exposures on clinical outcomes in COPD.ConclusionFungal sensitisation is prevalent in COPD and associates with frequent exacerbations representing a potential treatable trait. Outdoor and indoor (home) environments represent a key source of fungal allergen exposure, amenable to intervention, in “sensitised” COPD.

The thermophilic bacterium Geobacillus thermoleovorans was isolated from a tropical air sample collected in Singapore. The genome was sequenced on the PacBio RS II platform and consists of one chromosome with 3.6 Mb and one plasmid with 75 kb., The thermophilic bacterium Geobacillus thermoleovorans was isolated from a tropical air sample collected in Singapore. The genome was sequenced on the PacBio RS II platform and consists of one chromosome with 3.6 Mb and one plasmid with 75 kb. The genome comprises 3,509 protein-coding genes, 88 tRNAs, and 27 rRNAs.

Serratia marcescens strain SGAir0764 was isolated from a tropical air sample collected in Singapore. The complete genome, sequenced on the PacBio RS II platform, consists of one chromosome with 5.1 Mb and one plasmid with 76.4 kb., Serratia marcescens strain SGAir0764 was isolated from a tropical air sample collected in Singapore. The complete genome, sequenced on the PacBio RS II platform, consists of one chromosome with 5.1 Mb and one plasmid with 76.4 kb. Genome annotation predicts 4,723 protein-coding genes, 89 tRNAs, and 22 rRNAs.

Bacillus velezensis strain SGAir0473 (Firmicutes) was isolated from tropical air collected in Singapore. Its genome was assembled using short reads and single-molecule real-time sequencing and comprises one chromosome with 4.18 Mb., Bacillus velezensis strain SGAir0473 (Firmicutes) was isolated from tropical air collected in Singapore. Its genome was assembled using short reads and single-molecule real-time sequencing and comprises one chromosome with 4.18 Mb. The genome consists of 3,937 protein-coding genes, 86 tRNAs, and 27 rRNAs.

Pseudomonas stutzeri strain SGAir0442 was isolated from tropical air samples collected in Singapore. It is a Gram-negative denitrifying bacterium and an opportunistic human pathogen. Its complete genome consists of one chromosome of 4.52 Mb, containing 4,129 protein-coding genes, 12 rRNA subunits, and 62 tRNAs.

Staphylococcus haemolyticus is a coagulase-negative staphylococcal species that is part of the skin microbiome and an opportunistic human pathogen. The strain SGAir0252 was isolated from tropical air samples collected in Singapore, and its complete genome comprises one chromosome of 2.63 Mb and one plasmid of 41.6 kb.

Acinetobacter indicus ( Gammaproteobacteria ) is a strict aerobic nonmotile bacterium. The strain SGAir0564 was isolated from air samples collected in Singapore. The complete genome is 3.1 Mb and was assembled using a combination of short and long reads. The genome contains 2,808 protein-coding genes, 80 tRNAs, and 21 rRNA subunits.

Magnetic anisotropies of ferromagnetic thin films are induced by epitaxial strain from the substrate via strain-induced anisotropy in the orbital magnetic moment and that in the spatial distribution of spin-polarized electrons. However, the preferential orbital occupation in ferromagnetic metallic La$_{1-x}$Sr$_x$MnO$_3$ (LSMO) thin films studied by x-ray linear dichroism (XLD) has always been found out-of-plane for both tensile and compressive epitaxial strain and hence irrespective of the magnetic anisotropy. In order to resolve this mystery, we directly probed the preferential orbital occupation of spin-polarized electrons in LSMO thin films under strain by angle-dependent x-ray magnetic circular dichroism (XMCD). Anisotropy of the spin-density distribution was found to be in-plane for the tensile strain and out-of-plane for the compressive strain, consistent with the observed magnetic anisotropy. The ubiquitous out-of-plane preferential orbital occupation seen by XLD is attributed to the occupation of both spin-up and spin-down out-of-plane orbitals in the surface magnetic dead layer., Comment: 20 pages, 4 figures

Lelliottia nimipressuralis type strain SGAir0187 was isolated from tropical air samples collected in Singapore. The genome was assembled with an average coverage of 180-fold using Pacific Biosciences long reads and Illumina MiSeq paired-end reads. The genome measures 4.8 Mb and contains 4,424 protein-coding genes, 83 tRNAs, and 25 rRNAs.

Pantoea ananatis SGAir0210 was isolated from outdoor air collected in Singapore. The genome was assembled from long reads generated by single-molecule real-time sequencing complemented with short reads., Pantoea ananatis SGAir0210 was isolated from outdoor air collected in Singapore. The genome was assembled from long reads generated by single-molecule real-time sequencing complemented with short reads. The genome size was approximately 4.81 Mb, with 4,303 protein-coding genes, 80 tRNAs, and 22 rRNAs identified.

Acinetobacter schindleri strain SGAir0122 was isolated from tropical air samples collected in Singapore. The prevalence of nosocomial infection caused by this Gram-negative bacterium indicates its clinical significance as an opportunistic human pathogen., Acinetobacter schindleri strain SGAir0122 was isolated from tropical air samples collected in Singapore. The prevalence of nosocomial infection caused by this Gram-negative bacterium indicates its clinical significance as an opportunistic human pathogen. Its complete genome consists of one chromosome of 3.105 Mb and a plasmid of 181 kb.

Mammalian mitochondrial DNA (mtDNA) encodes 13 core proteins of oxidative phosphorylation, 12S and 16S ribosomal RNAs, and 22 transfer RNAs. Mutations and deletions of mtDNA and/or nuclear genes encoding mitochondrial proteins have been implicated in a wide range of diseases. Thus, cell survival and health of the organism require some steady-state level of the mitochondrial genome and its expression. In mammalian systems, the mitochondrial transcription factor B2 (mtTFB2 or TFB2M) is indispensable for transcription initiation. TFB2M along with two other proteins, mitochondrial RNA polymerase (mtRNAP or POLRMT) and mitochondrial transcription factor A (mtTFA or TFAM), are key components of the core mitochondrial transcription apparatus. Structural information for POLRMT and TFAM from humans is available; however, there is no available structure for TFB2M. In the present study, three-dimensional structure of TFB2M from humans was modeled using a combination of homology modeling and small-angle X-ray scattering (SAXS). The TFB2M structural model adds substantively to our understanding of TFB2M function. An explanation for the low or absent RNA methyltransferase activity is provided. A putative nucleic acid-binding site is revealed. The amino and carboxy termini, while likely lacking defined secondary structure, appear to adopt compact, globular conformations, thus "capping" the ends of the protein. Finally, sites of interaction of TFB2M with other factors, protein and/or nucleic acid, are suggested by the identification of species-specific clusters on the surface of the protein.

Human mtDNA contains three promoters, suggesting a need for differential expression of the mitochondrial genome. Studies of mitochondrial transcription have used a reductionist approach, perhaps masking differential regulation. Here we evaluate transcription from light-strand (LSP) and heavy-strand (HSP1) promoters using templates that mimic their natural context. These studies reveal sequences upstream, hypervariable in the human population (HVR3), and downstream of the HSP1 transcription start site required for maximal yield. The carboxy-terminal tail of TFAM is essential for activation of HSP1 but not LSP. Images of the template obtained by atomic force microscopy show that TFAM creates loops in a discrete region, the formation of which correlates with activation of HSP1; looping is lost in tail-deleted TFAM. Identification of HVR3 as a transcriptional regulatory element may contribute to between-individual variability in mitochondrial gene expression. The unique requirement of HSP1 for the TFAM tail may enable its regulation by post-translational modifications.

Bacillus altitudinis strain SGAir0031 ( Firmicutes ) was isolated from tropical air samples collected in Singapore. Its genome was assembled using short reads and single-molecule real-time sequencing, comprising one chromosome with 3.81 Mb and one plasmid with 32 kb. The genome consists of 3,820 protein-coding genes, 81 tRNAs, and 24 rRNAs.

Chenopodium album has a non-photosynthetic chlorophyll protein known as the water-soluble chlorophyll (Chl)-binding protein (WSCP). The C. album WSCP (CaWSCP) is able to photoconvert the chlorin skeleton of Chl a into a bacteriochlorin-like skeleton. Reducing reagents such as β-mercaptoethanol or dithiothreitol inhibit photoconversion, indicating that S–S bridge(s) in CaWSCP are quite important for it. Recently, we found that the mature region of CaWSCP contains five cysteine residues; Cys2, Cys30, Cys48, Cys63, and Cys144. To identify which cysteine residues are involved in the photoconversion, we generated five mutants (C2S, C30S, C48S, C63S, and C144S) by site-directed mutagenesis. Interestingly, C48S, C63S, and C144S mutants showed the same Chl-binding activity and photoconvertibility as those of the recombinant wild-type CaWSCP-His, while the C2S and C30S mutants completely lost Chl-binding activity. Our findings indicated that the S–S bridge between Cys2 and Cys30 in each CaWSCP subunit is essential for Chl-binding activity.

Water-soluble chlorophyll-binding proteins (WSCPs) are interesting model systems for the study of pigment-pigment and pigment-protein interactions. While class IIa WSCP has been extensively studied by spectroscopic and theoretical methods, a comprehensive spectroscopic study of class IIb WSCP was lacking so far despite the fact that its structure was determined by X-ray crystallography. In this paper, results of two-dimensional electronic spectroscopy applied to the class IIb WSCP from Lepidium virginicum are presented. Global analysis of 2D data allowed determination of energy levels and excitation energy transfer pathways in the system. Some additional pathways, not present in class IIa WSCP, were observed. The data were interpreted in terms of a model comprising two interacting chlorophyll dimers. In addition, oscillatory signals were observed and identified as coherent beatings of vibrational origin.

Various plants possess non-photosynthetic, hydrophilic chlorophyll (Chl) proteins called water-soluble Chl-binding proteins (WSCPs). WSCPs are categorized into two classes; Class I (photoconvertible type) and Class II (non-photoconvertible type). Among Class II WSCPs, only Lepidium virginicum WSCP (LvWSCP) exhibits a low Chl a/b ratio compared with that found in the leaf. Although the physicochemical properties of LvWSCP have been characterized, its molecular properties have not yet been documented. Here, we report the characteristics of the LvWSCP gene, the biochemical properties of a recombinant LvWSCP, and the intracellular localization of LvWSCP. The cloned LvWSCP gene possesses a 669-bp open reading frame. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis revealed that the precursor of LvWSCP contains both N- and C-terminal extension peptides. RT-PCR analysis revealed that LvWSCP was transcribed in various tissues, with the levels being higher in developing tissues. A recombinant LvWSCP and hexa-histidine fusion protein (LvWSCP-His) could remove Chls from the thylakoid in aqueous solution and showed an absorption spectrum identical to that of native LvWSCP. Although LvWSCP-His could bind both Chl a and Chl b, it bound almost exclusively to Chl b when reconstituted in 40 % methanol. To clarify the intracellular targeting functions of the N- and C-terminal extension peptides, we constructed transgenic Arabidopsis thaliana lines expressing the Venus protein fused with the LvWSCP N- and/or C-terminal peptides, as well as Venus fused at the C-terminus of LvWSCP. The results showed that the N-terminal peptide functioned in ER body targeting, while the C-terminal sequence did not act as a trailer peptide.

Hydrophilic chlorophyll (Chl)-binding proteins have been isolated from various Brassicaceae plants and are categorized into Class II water-soluble Chl-binding proteins (WSCPs). Although the molecular properties of class II WSCPs including Brassica-type (e.g., cauliflower WSCP, Brussels sprouts WSCP and BnD22, a drought- and salinity-stress-induced 22 kDa protein of rapeseed), a Lepidium-type, and an Arabidopsis-type WSCPs have been well characterized, those of Raphanus-type WSCPs are poorly understood. To gain insight into the molecular diversity of Class II WSCPs, we cloned a novel cDNA encoding a Raphanus sativus var. raphanistroides (Japanese wild radish called 'Hamadaikon') WSCP (RshWSCP). Sequence analysis revealed that the open reading frame of the RshWSCP gene consisted of 666 bp encoding 222 aa residues, including 23 residues of a deduced signal peptide. Functional recombinant RshWSCP was expressed in Escherichia coli as a hexa-histidine fusion protein (RshWSCP-His). Although the RshWSCP-His was expressed as a soluble protein in E. coli, the apo-protein was highly unstable and tended to aggregate during a series of purification steps. When the soluble fraction of RshWSCP-His-expressing E. coli was mixed immediately with homogenate of spinach leaves containing thylakoid, RshWSCP-His was able to remove Chl molecules from the thylakoid and formed a stable Chl-WSCP complex with high hydrophilicity. UV-visible absorption spectra of the reconstituted RshWSCP-His revealed that RshWSCP-His is one of the Class IIA WSCP with the highest Chl a/b ratio analyzed thus far. A semi-quantitative reverse transcription-polymerase chain reaction analysis revealed that RshWSCP was transcribed in buds and flowers but not in roots, stems and various leaves.

Air-conditioning systems harbor microorganisms, potentially spreading them to indoor environments. While air and surfaces in air-conditioning systems are periodically sampled as potential sources of indoor microbes, little is known about the dynamics of cooling coil-associated communities and their effect on the downstream airflow. Here, we conducted a 4-week time series sampling to characterize the succession of an air-conditioning duct and cooling coil after cleaning. Using an universal primer pair targeting hypervariable regions of the 16S/18S ribosomal RNA, we observed a community succession for the condensed water, with the most abundant airborne taxon Agaricomycetes fungi dominating the initial phase and Sphingomonas bacteria becoming the most prevalent taxa toward the end of the experiment. Duplicate air samples collected upstream and downstream of the coil suggest that the system does not act as ecological filter or source/sink for specific microbial taxa during the duration of the experiment. MOE (Min. of Education, S’pore) Accepted version

AmplifiedEptatretus okinoseanuscDNA was digested with NdeI and EcoRI, cloned into pCold trigger factor (TF), and transformed withEscherichia colistrain BL 21 in which a csp A promoter was introduced to inhibit the expression of foreign peptides. Recombinant lactate dehydrogenase (LDH) was obtained in the soluble fraction after sonication of the cells. The protein was digested by HRC 3C protease, thrombin, and factor Xa. The specific activity of TF-tagged protein and tagless protein were mIU/mg and mIU/mg, respectively. The deletion of the TF tag enhanced the activity compared with the native protein to mIU/mg, showing that this expression method is effective for the mass production of the protein to allow further study of the structure of LDH.

Magnetic anisotropy of epitaxially grown thin films is affected by the strain from the substrates due to a combined effect of distorted electronic structure and spin-orbit interaction (SOI). As an inverse process, one expects an anisotropy of the electronic structure induced by magnetization in the presence of SOI. We have studied the charge-density anisotropy induced by magnetization in thin films of the ferromagnetic metal La$_{1-x}$Sr$_{x}$MnO$_3$ via x-ray magnetic linear dichroism (XMLD). XMLD measurements on thin films with various thicknesses have shown that the XMLD intensity is proportional to the square of the ferromagnetic moment. Using the XMLD sum rule and cluster-model calculation, it has been shown that more Mn 3$d$ electrons are distributed in orbitals elongated along the direction parallel to the spin polarization than in orbitals elongated in the direction perpendicular to it. The cluster-model calculation has shown that the effect of tensile strain from the SrTiO$_3$ substrate on the XMLD spectra is also consistent with the observed XMLD spectral line shapes., Comment: 12 pages, 4 figures

Di-uracil substituted cyclen derivatives were prepared by the reaction of cyclen with 6-chloro-1-methyluracil or 6-chloro-1,3-dimethyluracil. The reaction of cyclam with 6-chloro-1,3-dimethyluracil gave a similar di-uracil substituted cyclam. The 1,7-di-uracil substituted cyclen was converted to the tricyclic guanidinium salt and acylurea upon heating in DMSO in the presence of weak acid. The 1,8-di-uracil substituted cyclam gave a tricyclic dihydroimidazolium salt under the same conditions. These reactions can be explained by an intramolecular uracil ring-breaking reaction mechanism.

RNA helicases function in numerous aspects of RNA biology. These enzymes are RNA-stimulated ATPases that translocate on RNA and unwind or remodel structured RNA in an ATP-dependent fashion. How ATP and the ATPase cycle fuel the work performed by helicases is not completely clear. The hepatitis C virus RNA helicase, NS3, is an important model system for this class of enzymes. NS3 binding to a single-/double-strand RNA or DNA junction leads to ATP-independent melting of the duplex and formation of a complex capable of ATP-dependent unwinding by using a spring-loaded mechanism. We have established an RNA substrate for NS3 that can be unwound in a single sub-step. Our studies are consistent with a model in which a single ATP binding and/or hydrolysis event sets the unwinding spring and phosphate dissociation contributes to release of the spring, thereby driving the power stroke used for unwinding.

Maternal diabetes during pregnancy increases the risk of congenital malformations such as neural tube defects (NTDs). Although the mechanism of this effect is uncertain, it is known that levels of nitric oxide synthase (NOS) and nitric oxide are elevated in embryos of a mouse model of diabetes. We postulated that overproduction of nitric oxide causes diabetes-induced congenital malformations and that inhibition of inducible NOS (iNOS) might prevent diabetic embryopathy.Mice were rendered hyperglycaemic by intraperitoneal injection of streptozotocin. The incidence of congenital malformations including NTDs was evaluated on gestational day 18.5. We assessed the involvement of iNOS in diabetes-induced malformation by administering ONO-1714, a specific inhibitor of iNOS, to pregnant mice with streptozotocin-induced diabetic mice and by screening mice with iNOS deficiency due to genetic knockout (iNos(-/-)).ONO-1714 markedly reduced the incidence of congenital anomalies, including NTDs, in fetuses of a mouse model of diabetes. It also prevented apoptosis in the head region of fetuses, indicating that iNOS is involved in diabetes-related congenital malformations. Indeed, no NTDs were observed in fetuses of diabetic iNos(-/-) mice and the incidence of other malformations was also markedly reduced.We conclude that increased iNOS activity during organogenesis plays a crucial role in the pathogenesis of diabetes-induced malformations and suggest that inhibitors of iNOS might help prevent malformations, especially NTDs, in diabetic pregnancy.

Nucleic acid polymerases catalyze the formation of DNA or RNA from nucleoside-triphosphate precursors. Amino acid residues in the active site of polymerases are thought to contribute only indirectly to catalysis by serving as ligands for the two divalent cations that are required for activity or substrate binding. Two proton-transfer reactions are necessary for polymerase-catalyzed nucleotidyl transfer: deprotonation of the 3'-hydroxyl nucleophile and protonation of the pyrophosphate leaving group. Using model enzymes representing all four classes of nucleic acid polymerases, we show that the proton donor to pyrophosphate is an active-site amino acid residue. The use of general acid catalysis by polymerases extends the mechanism of nucleotidyl transfer beyond that of the well-established two-metal-ion mechanism. The existence of an active-site residue that regulates polymerase catalysis may permit manipulation of viral polymerase replication speed and/or fidelity for virus attenuation and vaccine development.

It is well known that maternal diabetes causes various congenital malformations. Although there are many reports that folic acid (FA) administration in pregnancy reduces the risk of birth defects including neural tube defects (NTDs), a precise analysis on the preventive effect of FA against diabetic embryopathy has not been done yet. In this study, we analyzed the preventive effects of FA on congenital malformations including NTDs, cardiovascular, and skeletal malformations using a diabetic mouse model. Female mice were rendered hyperglycemic by streptozotocin and then mated. Pregnant diabetic mice were treated daily with FA (3 mg/kg body weight) or saline between gestational days (GD) 6 and 10. On GD 18, fetuses were examined for congenital malformations. FA did not affect plasma glucose levels. In the DM control group, the incidence of NTDs, cardiovascular, and skeletal malformations was 28.4%, 28.5%, and 29.7%, respectively. In the FA-treated group, the corresponding proportions reduced to 6.0%, 2.5% and 12.5%, respectively. A whole-mount TUNEL revealed an increased apoptosis in the hindbrain region of embryos from DM control group on day 9.5, and the apoptosis was decreased by FA treatment. Maternal plasma homocysteine levels on GD 9.5 were significantly lowered in DM control group compared with those in non-DM group, and FA treatment did not show a significant effect. These results indicate that FA is effective for the prevention of various diabetic embryopathy including NTDs, cardiovascular, and skeletal malformations, and suggested that this effect is independent from homocysteine metabolism and possibly mediated by decreasing the abnormal apoptosis during organogenesis.

A new Encryption-then-Compression (ETC) system for the JPEG 2000 standard is proposed in this paper. An ETC system is known as a system that makes image communication secure and efficient by using perceptual encryption and image compression. The proposed system uses the sign-scrambling and block-shuffling of discrete wavelet transform (DWT) coefficients as perceptual encryption. Unlike conventional ETC systems, the proposed system is compatible with the JPEG 2000 standard because the perceptually encrypted coefficients can be efficiently compressed by the JPEG 2000. The experimental results demonstrated that the proposed system achieved both acceptable compression performance and enough key-space for secure image communication while remaining compatible with the JPEG 2000 standard.

A variety of perceptual encryption schemes have been studied to generate visually encrypted images for protecting visual secrecy and privacy while supporting ongoing innovation and growth in the applications of digital imagery. However, typical image quality metrics such as PSNR and SSIM are not suitable to evaluate the invisibility of visually encrypted images. To overcome this issue, this paper proposes a novel full-reference invisibility index, referred to as the Triple feature similarity index (TFSI), for visually encrypted images. The TFSI is computed through four steps: 1) edge extraction as preprocessing, 2) extracting the Triple feature based on the Trace transform, 3) normalization of resolution, and 4) TFSI is computed between the reference and visually encrypted images. Experimental results show that the TFSI measures the invisibility of visually encrypted images.

A diastereomeric mixture of racemic α-amino nitriles [1SR,2RS,(SR)]- (1) and [1SR,2RS,(RS)]-N-cyano(phenyl)methyl-1-aminoindan-2-ol (2) was thermally epimerized in the solid state to give diastereopure [1SR,2RS,(SR)]-1. The reaction was about 26 times slower than the same reaction of a mixture of their enantiopure counterparts, showing that different mechanisms operated between the two transformations. X-ray crystallographic analysis revealed that in the former transformation, racemic-compound crystals of 2 were converted into conglomerate crystals of 1, while in the latter, enantiomeric crystals of 2 were converted into enantiomeric crystals of 1. The difference in the reactivity toward the epimerization between the racemic and the enantiopure mixture could be rationalized by the difference in the stability of compound 2 in the two crystal forms.

The polycyclic aromatic ketone, 13H-dibenzo[a,de]anthracene-13-one (5,6-BBz) is useful as a starting material for synthesis of undecacyclic aromatic compounds by means of condensation. To synthesize 5,6-BBz, glycerol condensation of benzo[a]anthraquinone was conducted. The condensation, however, gave two structural isomers besides 5,6-BBz and the isolation was very difficult; separation of the crude products by column chromatography or high-vacuum sublimation was unsuccessful because of their similarity in structure and vapor pressure. Only a little 5,6-BBz was obtained by repeated recrystallization, but the amount was insufficient for condensation. Thus, we developed a new synthetic method which affords 5,6-BBz selectively. 9-(o-Chlorobenzoyl)anthracene was synthesized by the Friedel-Crafts' reaction of anthracene with o-chlorobenzoyl chloride and aluminum chloride anhydride. In order to suppress the production of 9,10-di(o-chlorobenzoyl) anthracene, the reaction was performed at low temperature. The cru...

cis,cis,cis-1,2,4,5-Cyclohexanetetracarboxylic acid, C(10)H(12)O(8), (I), contains a mirror plane and the cyclohexane ring exhibits a chair conformation. Two crystallographically independent hydrogen bonds form R(2)(2)(14), R(2)(2)(16) and R(4)(4)(16) ring motifs, and propagation of these two hydrogen bonds along the c and b axes generates C(2)(2)(16) and C(2)(2)(7) chains. cis,cis,cis-1,2:4,5-Cyclohexanetetracarboxylic dianhydride, C(10)H(8)O(6), (II), was prepared by the reaction of (I) with acetic anhydride. The cyclohexane ring of (II) exhibits a boat conformation and the dihedral angle between the two anhydro rings is 117.5 (1) degrees.

The objective of this study is to determine the causes of asymmetry of the lateral ventricles in neonates. We also studied the effect of head position and the relationship of body weight at birth in regard to lateral ventricular size. Eligible for inclusion in this study were 60 neonatal infants whose gestational age was 33.1+/-3.5 weeks and whose birth weight was 1793+/-613 g. Ultrasonographic examinations were performed at the first and the second weeks after birth. In parasagittal and coronal scans through the posterior horn of the lateral ventricle, the lateral ventricle was traced and its area was measured. We found no significant variation of ventricular size in relation to body weight at birth. The left ventricular size was larger than the right one. The difference of the left and right ventricular sizes was partially effected by head position. The ratio of left to right lateral ventricular sizes showed a very wide distribution. We considered that ventricular asymmetry is not pathological, but due to individual differences.

This article describes the photooxidation of benzo[ de ]naphtho-[2,1,8,7- stuv ]anthra[2,1,9,8- hijkl ]pentacene (BNAP) synthesized by the condensation of naphthanthrone with zinc dust. When an o -...

The relation between the yields of three isomers of violanthrone--violanthrone A (VOA), violanthrone B (VOB), and isoviolanthrone A (isoVOA)--and the condition of the alkali fusion of benzanthrone have been studied. When the method of alcoholic alkali fusion was applied to benzanthrone at low temperature, the major product was VOB. On the other hand, it was reported by Di Raddo et al. (2) that isoVOA was not obtained as a by-product under proper conditions (alkali fusion at high temperature) of synthesizing VOA. However, the result by the present authors is that 6 ∼ 7 percent of the A compound is isoVOA.

We investigated the effects of near-infrared irradiation on the photoconversion of Chenopodium album water-soluble chlorophyll-binding protein (CaWSCP) in the presence of sodium hydrosulfite and found a further photoconversion from CP742 to CP763, a novel form of CaWSCP. Interestingly, one-third of the absorption peak at 668 nm was recovered in CP763, but re-irradiation under oxidative conditions eliminated the photo convertibility of CaWSCP.

Non-photosynthetic and hydrophilic chlorophyll (Chl) proteins, called water-soluble Chl-binding proteins (WSCPs), are distributed in various species of Chenopodiaceae, Amaranthaceae, Polygonaceae and Brassicaceae. Based on their photoconvertibility, WSCPs are categorised into two classes: Class I (photoconvertible) and Class II (non-photoconvertible). Chenopodium album WSCP (CaWSCP; Class I) is able to convert the chlorin skeleton of Chl a into a bacteriochlorin-like skeleton under light in the presence of molecular oxygen. Potassium iodide (KI) is a strong inhibitor of the photoconversion. Because KI attacks tyrosine residues in proteins, tyrosine residues in CaWSCP are considered to be important amino acid residues for the photoconversion. Recently, we identified the gene encoding CaWSCP and found that the mature region of CaWSCP contained four tyrosine residues: Tyr13, Tyr14, Tyr87 and Tyr134. To gain insight into the effect of the tyrosine residues on the photoconversion, we constructed 15 mutant proteins (Y13A, Y14A, Y87A, Y134A, Y13-14A, Y13-87A, Y13-134A, Y14-87A, Y14-134A, Y87-134A, Y13-14-87A, Y13-14-134A, Y13-87-134A, Y14-87-134A and Y13-14-87-134A) using site-directed mutagenesis. Amazingly, all the mutant proteins retained not only chlorophyll-binding activity, but also photoconvertibility. Furthermore, we found that KI strongly inhibited the photoconversion of Y13-14-87-134A. These findings indicated that the four tyrosine residues are not essential for the photoconversion.

Water-soluble chlorophyll (Chl)-binding proteins (WSCPs) have been found in various plants. WSCPs are categorized into two classes based on their photoconvertibility: Class I (photoconvertible) and Class II (non-photoconvertible). Based on their absorption peaks, which occur in the red wavelengths, the pre- and post-photoconverted forms of Chenopodium album WSCP (CaWSCP) are called CP668 and CP742, respectively. Although various biochemical and biophysical properties of CaWSCP have already been characterized, questions remain regarding the structural dynamics of the photoconversion from CP668 to CP742, and the relationship between the photoconversion activity and incident light wavelength. To address how the wavelength of incident light affects the photoconversion, we performed time-course analyses of CaWSCP photoconversion by using light-emitting diodes that emit either white light, or at the discrete wavelengths 670, 645, 525, 470, or 430 nm. The most efficient photoconversion was observed under irradiation at 430 nm. Less efficient photoconversion was observed under irradiation with 670, 645, 470, or 525 nm light, in that order. The relationship between photoconversion activity and wavelength corresponded with the absorption peak intensities of Chls in the CaWSCP complex. The observed time dependence of the A(742)/A(668) ratio during photoconversion of the CaWSCP complex indicated that the photoconversion from CP668 to CP742 occurs in a three-step reaction, and that only three subunits in the complex could be photoconverted.