Crystal structures of cyclomaltohexaose (α-cyclodextrin) complexes with p-chlorophenol and p-cresol

Crystal structures of cyclomaltohexaose (α-cyclodextrin) complexes with p-chlorophenol and p-cresol have been determined by single-crystal X-ray diffraction studies. The space group of the α-cyclodextrin–p-chlorophenol complex is P2₁2₁2₁ with unit cell dimensions of a=15.299(3), b=24.795(5), c=13.447(5) Å, and that of the α-cyclodextrin–p-cresol complex is P2₁ with unit cell dimensions of a=7.927(7), b=13.568(7), c=24.54(1) Å, β=90.41(8)°. In spite of the similar structures of guest molecules, both complexes have different inclusion modes and packing structures.     

Mechanisms of heart development in the Japanese lamprey, Lethenteron japonicum

SUMMARY Vertebrate hearts have evolved from undivided tubular hearts of chordate ancestors. One of the most intriguing issues in heart evolution is the abrupt appearance of multichambered hearts in the agnathan vertebrates. To explore the developmental mechanisms behind the drastic morphological changes that led to complex vertebrate hearts, we examined the developmental patterning of the agnathan lamprey Lethenteron japonicum . We isolated lamprey orthologs of genes thought to be essential for heart development in chicken and mouse embryos, including genes responsible for differentiation and proliferation of the myocardium ( LjTbx20, LjTbx4/5 , and LjIsl1/2A ), establishment of left–right heart asymmetry ( LjPitxA ), and partitioning of the heart tube ( LjTbx2/3A ), and studied their expression patterns during lamprey cardiogenesis. We confirmed the presence of the cardiac progenitors expressing LjIsl1/2A in the pharyngeal and splanchnic mesoderm and the heart tube of the lamprey. The presence of LjIsl1/2A -positive cardiac progenitor cells in cardiogenesis may have permitted an increase of myocardial size in vertebrates. We also observed LjPitxA expression in the left side of lamprey cardiac mesoderm, suggesting that asymmetric expression of Pitx in the heart has been acquired in the vertebrate lineage. Additionally, we observed LjTbx2/3A expression in the nonchambered myocardium, supporting the view that acquisition of Tbx2/3 expression may have allowed primitive tubular hearts to partition, giving rise to multichambered hearts.     

Molecular Properties and Extracellular Processing of the Lipase of Staphylococcus warneri M

Staphylococcus warneri M exhibited extracellular lipase activity. By zymogram analysis of extracellular proteins, multiple bands were detected and the profiles changed depending on the bacterial growth phase. N-terminal amino acid sequences of three bands (N1-N3) were determined. From the genome library of S. warneri M whole DNA, the gene-directing lipase activity (named gehC(WM)) was cloned and characterized. The gehC(WM )gene encoded a protein (GehC(WM)), whose calculated molecular mass was 83.4 kDa, and the sequence was similar to the other staphylococcal lipases. Though two lipases have been known from S. warneri 863, GehC(WM) differs from both of them, indicating that this enzyme is the third extracellular lipase of the S. warneri strain. The N-terminal sequences of the N1-N3 polypeptides completely coincided with the deduced amino acid sequences in GehC(WM). GehC(WM) was predicted to be a prepro-protein. In vitro processing and protein sequencing suggested that pro-GehC(WM) is possibly processed by extracellular glutamyl endopeptidase, PROM. Inductively coupled plasma-atomic emission spectrometer analysis showed that purified his-tagged mature GehC(WM) possessed zinc ion. A gehC(WM) knockout mutant was constructed by insertion of an erythromycin resistance gene into the gehC(WM). Zymogram and immunoblot analyses of the gehC(WM )mutant indicated that GehC(WM) was a major extracellular lipase of S. warneri M.     

Effects of a high-salt diet on adipocyte glucocorticoid receptor and 11-β hydroxysteroid dehydrogenase 1 in salt-sensitive hypertensive rats

High-salt diets decrease insulin sensitivity in salt-sensitive hypertensive rats, and glucocorticoids promote adipocyte growth and may have pathophysiological roles in the metabolic syndrome. The aim of this study was to clarify the relationship between high-salt diet and the adipocyte glucocorticoid hormones in salt-sensitive hypertensive rats. Six-week-old Dahl salt-sensitive (DS) hypertensive rats and salt-resistant (DR) rats were fed a high-salt diet or a normal-salt diet for 4 weeks. Fasting blood glucose (FBG), serum adiponectin, plasma insulin, and corticosterone in plasma and in visceral adipose tissues, 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) activities in adipose tissues and glucose uptake in isolated muscle were measured. Animals underwent an oral glucose tolerance test (OGTT). The expression of mRNA for glucocorticoid receptor (GR), 11β-HSD1 and tumor necrosis factor-α (TNF-α) in adipose tissues were measured using a real-time PCR. A high-salt diet did not influence FBG; however, decreased 2-deoxy glucose uptake and plasma insulin during OGTT in DS rats. The high-salt diet increased significantly adipose tissue corticosterone concentration and 11β-HSD1 activities, gene expression for GR, 11β-HSD1 and TNF-α in adipose tissues in DS rats compared with DR rats (p < 0.05). The high-salt diet did not influence plasma corticosterone and serum adiponectin concentration in DS and DR rats. These results suggest that changes in GR and 11β-HSD1 in adipose tissue may contribute to insulin sensitivity in salt-sensitive hypertensive rats.     

N-acetylchitosan gel: A polyhydrate of chitin

N-Acetylchitosan gel, a polyhydrate of chitin, and partially O-acetylated N-acetylchitosan gel were produced by a facile acetylation of chitosan with acetic anhydride in 10% acetic acid and in aqueous acetic acid/methanol at room temperature. Under the same conditions, a series of N-acylchitosan gels was produced in reaction with the other carboxylic anhydrides. The gels thus produced were colorless, transparent and rigid, and stable on heating. The gels were insoluble in cold and boiling water, formic acid, aqueous acids, and the other solvents examined. Significant changes in specific rotation occurred in the acylation of chitosan and its aggregation.     

The effects of N-substitution of chitosan and the physical form of the products on the rate of hydrolysis by chitinase from Streptomyces griseus

N-Formyl, N-chloroacetyl, N-glycyl, N-isobutyryl, and N-pentanoyl derivatives of chitosan have been prepared. N-Acetylchitosan was the derivative most susceptible to chitinase from Streptomyces griseus and lysozyme from chicken egg-white, but the susceptibility was not restrictive. The relative rates of hydrolysis by chitinase with respect to R in the RCONH group were CH₃ > CH₃CH₂ > H > CH₃CH₂CH₂ > (CH₃)₂CH > NH₂CH₂ > ClCH₂. Neither enzyme hydrolysed chitosan or its N-methylene, N-benzylidene, N-benzoyl, N-nicotinyl, and N-fatty acyl (C₅C₁₈) derivatives, and lysozyme did not hydrolyse N-butyrylchitosan. N-Acetylhexanoyl-chitosans, which had d.s. ratios of ~0.7: ~0.3 and ~0.3; ~0.7, were hydrolysed at ~0.75 and ~0.04 of the rate of N-acetylchitosan (powder) by chitinase. O-Acylation of N-acylchitosans caused a decrease in the rates of hydrolysis by chitinase. N-Acetylchitosan gels were hydrolysed at 8–13 times the rate for crab-shell chitin. These results indicate that not only N- and O-substituents but also the physical form of the substrates influence the rates of hydrolysis by these enzymes.     

Resolution of anomeric 2-amino-2-deoxy-d-glycofuranosides and -glycopyranosides by cation-exchange chromatography

Methyl 4,6-O-benzylidene-2-deoxy-α-D-ribo-hexopyranoside (1) is converted into methyl 3,4-di-O-benzoyl-6-bromo-2,6-dideoxy-α-D-ribo-hexopyranoside (3) via the 3-O-benzoyl derivative (2) of 1 by subsequent treatment with N-bromosuccinimide. Compound 3 is the key intermediate in high-yielding, preparative syntheses of the title dideoxy sugars, which are constituents of many antibiotics. Dehydrohalogenation of 3 affords the 5,6-unsaturated glycoside 7. which undergoes stereospecific reduction by hydrogen with net inversion at C-5 to give methyl 3,4-di-O-benzoyl-2,6-dideoxy-β-L-lyxo-hexopyranoside (8), whereas reductive dehalogenation of 3 provides the corresponding D-ribo derivative 4. The unprotected glycosides 9 (L-lyxo) and 5 (D-ribo) are readily obtained by catalytic transesterification, and mild, acid hydrolysis gives the crystalline title sugars 10 (L-lyxo) and 6 (D-ribo) in 45 and 57% overall yield from 1 without the necessity of chromatographic purification at any of the steps.     

Representation of a mixture of pheromone and host plant odor by antennal lobe projection neurons of the silkmoth Bombyx mori

Pheromone-source orientation behavior can be modified by coexisting plant volatiles. Some host plant volatiles enhance the pheromonal responses of olfactory receptor neurons and increase the sensitivity of orientation behavior in the Lepidoptera species. Although many electrophysiological studies have focused on the pheromonal response of olfactory interneurons, the response to the mixture of pheromone and plant odor is not yet known. Using the silkmoth, Bombyx mori, we investigated the physiology of interneurons in the antennal lobe (AL), the primary olfactory center in the insect brain, in response to a mixture of the primary pheromone component bombykol and cis-3-hexen-1-ol, a mulberry leaf volatile. Application of the mixture enhanced the pheromonal responses of projection neurons innervating the macroglomerular complex in the AL. In contrast, the mixture of pheromone and cis-3-hexen-1-ol had little influence on the responses of projection neurons innervating the ordinary glomeruli whereas other plant odors dynamically modified the response. Together this suggests moths can process plant odor information under conditions of simultaneous exposure to sex pheromone.     

Isolation of Ef silicatein and Ef lectin as molecular markers for sclerocytes and cells involved in innate immunity in the freshwater sponge Ephydatia fluviatilis

Sponges (phylum Porifera) have remarkable regenerative and reconstitutive abilities and represent evolutionarily the oldest metazoans. To investigate sponge stem cell differentiation, we have focused on the asexual reproductive system in the freshwater sponge Ephydatia fluviatilis. During germination, thousands of stem cells proliferate and differentiate to form a fully functional sponge. As an initial step of our investigation of stem cell (archeocyte) differentiation, we isolated molecular markers for two differentiated cell types: spicule-making sclerocyte cells, and cells involved in innate immunity. Sclerocyte lineage-specific Ef silicatein shares 45% to 62% identity with other sponge silicateins. As in situ hybridization of Ef silicatein specifically detects archeocytes possibly committed to sclerocytes, as well as sclerocytes with an immature or mature spicule, therefore covering all the developmental stages, we conclude that Ef silicatein is a suitable sclerocyte lineage marker. Ef lectin, a marker for the cell type involved in innate immunity, shares 59% to 65% identity with the marine sponge Suberites domuncula galactose-binding protein (Sd GBP) and horseshoe crab Tachypleus tridentatus tachylectin1/lectinL6. Since Sd GBP and tachylectin1 are known to bind to bacterial lipopolysaccharides and inhibit the growth of bacteria, Ef lectin may have a similar function and be expressed in a specialized type of cell involved in defense against invading bacteria. Ef lectin mRNA and protein are not expressed in early stages of development, but are detected in late stages. Therefore, Ef lectin may be specifically expressed in differentiating and/or differentiated cells. We suggest Ef lectin as a marker for cells that assume innate immunity in freshwater sponges.