Regeneration of tunic cuticle is suppressed in edible ascidian Halocynthia roretzi contracting soft tunic syndrome.

Soft tunic syndrome is an infectious disease caused by the flagellate Azumiobodo hoyamushi, which severely damages the aquaculture of the edible ascidian Halocynthia roretzi. Tunic is a cellulosic extracellular matrix entirely covering the body in ascidians and other tunicates, and its dense cuticle layer covers the tunic surface as a physical barrier against microorganisms. When the tunic of intact H. roretzi individuals was cut into strips, electron-dense fibers (DFs) appeared on the cut surface of the tunic matrix and aggregated to regenerate a new cuticular layer in seawater within a few days. DF formation was partially or completely inhibited in individuals with soft tunic syndrome, and DF formation was also inhibited by the presence of some proteases, indicating the involvement of proteolysis in the process of tunic softening as well as cuticle regeneration. Using pure cultures of the causative flagellate A. hoyamushi, the expression of protease genes and secretion of some proteases were confirmed by RNA-seq analysis and a 4-methylcoumaryl-7-amide substrate assay. Some of these proteases may degrade proteins in the tunic matrix. These findings suggest that the proteases of A. hoyamushi is the key to understanding the mechanisms of cuticular regeneration inhibition and tunic softening.

Fucoidan from brown seaweed Tubinaria decurrens: Structure and structure - anticancer activity relationship.

The aims of this study are to determine the structure of a fucoidan from brown seaweed Turbinaria decurrens, to investigate its anticancer activity and structure-activity relationship. SEC-MALLS, IR, ESI-MS and NMR spectra analysis indicated that dominant structure of the fucoidan, with a Mw 122.6 KDa, has a backbone of (1 â†’ 3)- and (1 â†’ 4)-α-L-Fucp residues, branched at C-4, sulfate groups are attached at C-2, C-3 and C-4; branches are (1 â†’ 4)-ß-D-Galp residues and sulfated at C-2. The fucoidan was hydrolyzed by HCl aqueous solution to obtain hydrolyzed fucoidans. It is assumed that native and hydrolyzed fucoidans have a rod-like conformation in solution with cross-sectional radius of gyration (Rgc) ranged from 0.53 to 1.52 nm as estimated from SAXS measurements. The fucoidans show great anticancer activity against HT29 human colon cancer cell line with IC50 ranging from 5.41 ± 0.36 to 73.52 ± 2.54 µg/mL. Anticancer activity of the fucoidan could be significantly improved by lowering molecular weight, furthermore, fucoidan required small molecular weight, small molecular weight distribution and rod-like structure with a short branch length for high anticancer activity.

Metagenomic profile of caudal fin morphology of farmed red sea bream Pagrus major.

The morphology of farm-reared fish often differs from that of their wild counterparts, impacting their market value. Two caudal fin tip shapes, acutely angled and blunted, are recognized in farmed populations of red sea bream Pagrus major. The angled form is preferred by consumers over the blunt since it resembles that of wild fish. Discovering the cause of the blunted tip is crucial to maximizing the commercial value of farmed red sea bream. We hypothesized that the blunt fin tip is the result of opportunistic bacteria and conducted partial 16S rRNA metagenomic barcoding and generated a clone library of the 16S rRNA gene to compare bacterial communities of the 2 fin forms. Metagenomic barcoding revealed an abundance of 5 bacterial genera, Sulfitobacter, Vibrio, Tenacibaculum, Psychrobacter, and an unknown genus of Rhodobacteraceae, on the caudal fin surface. Sulfitobacter was significantly more common on the angled caudal fin than the blunted. Vibrio is the dominant genus on the blunted caudal fin. The clone library identified these genera to species level, and Sulfitobacter sp., Vibrio harveyi, Tenacibaculum maritimum, and Psychrobacter marincola were frequently observed in blunt caudal fins. Our results suggest that opportunistic pathogenic bacteria such as V. harveyi and T. maritimum are not the primary cause of caudal fin malformation, and multiple factors such as combinations of injury, stress, and pathogenic infection may be involved. The reason for the significantly greater occurrence of Sulfitobacter sp. in the angled caudal fin is unknown, and further investigation is needed.

Dynamic changes and importance of plasma concentrations of ether phospholipids, of which the majority are plasmalogens, in postpartum Holstein dairy cows.

CONTEXT: Ethanolamine plasmalogens (EPls) and choline plasmalogens (CPls) are classes of ethanolamine ether phospholipids (ePE) and choline ether phospholipids (ePC), respectively. EPls play crucial roles in maternal and breastfed infant bodies and stimulate gonadotropin secretion by gonadotrophs. AIMS: To estimate changes in and importance of plasma concentrations of EPls and CPls, utilising newly developed enzymatic fluorometric assays for ePE and ePC in postpartum Holstein cows. METHODS: Plasma samples were collected from 3weeks before expected parturition until approximately 8weeks after parturition (16 primiparous and 38 multiparous cows) for analysis. KEY RESULTS: Plasma concentrations of ePE and ePC, most of which are plasmalogens, declined before and increased after parturition and stabilised near the day of the first postpartum ovulation (1stOV). From weeks 2 to 3 after parturition, third-parity cows exhibited ePE concentrations that were higher than those of other parity cows. The days from parturition to 1stOV correlated with days from parturition to conception. On the day of 1stOV, milk yield correlated with plasma concentration of both ePE and ePC, while ePC concentration correlated negatively with milk fat percentage. At the early luteal phase after 1stOV, plasma ePE concentration correlated with plasma anti-Müllerian hormone concentration (r =0.39, P <0.01), and plasma ePC concentration correlated with plasma follicle-stimulating hormone concentration (r =0.43, P <0.01). CONCLUSION: The concentrations of ePE and ePC changed dramatically around parturition and 1stOV, and the concentrations correlated with important parameters for milk production and reproduction. IMPLICATIONS: The blood plasmalogen may play important roles in postpartum dairy cows.

Redescription and molecular characterization of Mothocya parvostis Bruce, 1986 (Crustacea: Isopoda: Cymothoidae) parasitic on Japanese halfbeak, Hyporhamphus sajori (Temminck & Schlegel, 1846) (Hemiramphidae) with Mothocya sajori Bruce, 1986 placed into synonymy.

Two species of Mothocya have previously been recorded from Hyporhamphus sajori: M. parvostis Bruce, 1986 and M. sajori Bruce, 1986. Mothocya parvostis is re-described based on the ovigerous female type and additional materials collected from the host from in and around the type locality. Morphological re-examination of fresh specimens and the type materials together with genetic data show that the M. sajori and M. parvostis are the same species, differing primarily in size, therefore we have placed Mothocya sajori Bruce, 1986 into a junior synonym of Mothocya parvostis Bruce, 1986. Mothocya parvostis is characterized by the following combinations of characters: 1) body slightly to moderately twisted to one side; 2) pereonite 7 posterior margin moderately to deeply recessed; 3) uropodal rami extending to pleotelson posterior margin; and 4) uropod rami bluntly rounded, exopod 1.5 times as long as peduncle. The differences of four morphological features for M. parvostis and M. sajori was quantified. Furthermore, a total of 635 isopods infesting H. sajori were collected from all over Japan to conduct quantitative morphological and molecular sequence analyses (mitochondrial cytochrome c oxidase subunit I and 16S rRNA). Although the four quantitative features did not overlap between the two species in type specimens, all quantitative morphological values of newly collected specimens in this study did not display a bimodal distribution. In addition, our molecular analyses found only a single clade for our newly collected specimens in neighbor-joining tree.

Ethanolamine plasmalogens derived from whale brain stimulate both follicle-stimulating hormone and luteinizing hormone secretion by bovine gonadotrophs.

Ethanolamine plasmalogens (EPls) are the only known ligands of a novel receptor, G protein-coupled receptor 61, and bovine brain EPls stimulate follicle-stimulating hormone (FSH) but not luteinizing hormone (LH), secreted by bovine gonadotrophs. We hypothesized that the brain EPls of whales (Balaenoptera edeni), another Cetartiodactyla with at least twice the lifespan of bovines, could stimulate FSH secretion by gonadotrophs. To test this hypothesis, bovine gonadotrophs (from approximately 2-year-old Japanese Black heifers) were cultured for 3.5 days and treated with increasing concentrations of brain EP1s from whales (approximately 22 years old). FSH and LH secretion was stimulated by all tested concentrations of whale EPls (p < 0.05). To clarify the important differences between bovine and whale EPls, we utilized two-dimensional liquid chromatography-mass spectrometry, which revealed 35 peaks. Among them, we observed significant differences between 12 EPl molecular species. Additionally, we identified differentially expressed genes for enzymes involved in EPl synthesis or degradation in the hypothalamus of young heifers and old cows (approximately 10 years old) as compared to whales (approximately 28 years old) via deep sequencing of the transcriptome. We conclude that whale brains contain unique EPls that stimulate both FSH and LH secretion by bovine gonadotrophs.

Ethanolamine plasmalogens derived from scallops stimulate both follicle-stimulating hormone and luteinizing hormone secretion by bovine gonadotrophs.

Brain ethanolamine plasmalogens (EPls) are the only known ligands of G-protein-coupled receptor 61, a novel receptor that stimulates follicle-stimulating hormone (FSH), but not luteinizing hormone (LH), secretion by bovine gonadotrophs. We hypothesized that the recently developed neuroprotective EPls extracted from scallop (Pecten yessoensis) (scallop EPls) could stimulate FSH secretion by gonadotrophs. To test this hypothesis, bovine gonadotrophs were cultured for 3.5 days and treated with increasing concentrations of scallop EPls. FSH secretion was stimulated by all tested concentrations of scallop EPls (P < 0.05). Surprisingly, LH secretion was stimulated by both 0.5 (P < 0.05) and 5 (P < 0.01) ng/mL of scallop EPls. To clarify the important differences between bovine brain and scallop EPls, we utilized two-dimensional liquid chromatography-mass spectrometry, which revealed 44 peaks, including 10 large peaks. Among them, eight were scallop-specific EPl molecular species, occupying approximately 58% of the total area percentage of scallop EPls. Almost all large peaks contained 4, 5, or 6 unsaturated double bonds in the carbon chain at the sn-2 position of the glycerol backbone. Our results showed that EPls from scallops, lacking pituitary glands, stimulated both FSH and LH secretion by bovine gonadotrophs.

Innate immunity in the edible ascidian Halocynthia roretzi developing soft tunic syndrome: Hemolymph can eliminate the causative flagellates and discriminate allogeneic hemocytes.

The infection of the kinetoplastid flagellate Azumiobodo hoyamushi causes soft tunic syndrome that often results in mass mortality in the aquaculture of the edible ascidian Halocynthia roretzi. In the diseased ascidian individuals, the flagellates are exclusively found in the tunic matrix that entirely cover the epidermis, and never invade into internal tissues, such as a mantle. The present study for the first time demonstrated that the ascidian blood plasma and hemolymph have an activity to agglutinate and disintegrate the flagellates, suggesting the innate immunity protects the internal tissue from the invasion of A. hoyamushi. This activity is indifferent between the healthy and the diseased individuals. Allo-specific recognition and cytotoxic reaction among ascidian hemocytes, so-called contact reaction, occur among the individuals of healthy-healthy, healthy-diseased, and diseased-diseased combination, and therefore, the hemocytes from diseased individuals still retain the allo-reactivity. Moreover, the allo-reactive combinations are not changed under the presence of the flagellates, indicating the flagellates neither suppress nor induce the effector system of the contact reaction. These results suggest that the infection of A. hoyamushi does not impair the innate immunity in the ascidian hemolymph.

Physicochemical functionality of chimeric isomaltomegalosaccharides with α-(1 → 4)-glucosidic segments of various lengths.

Isomaltomegalosaccharide (IMS) is a long chimeric glucosaccharide composed of α-(1 â†’ 6)- and α-(1 â†’ 4)-linked segments at nonreducing and reducing ends, respectively; the hydrophilicity and hydrophobicity of these segments are expected to lead to bifunctionality. We enzymatically synthesized IMS with average degrees of polymerization (DPs) of 15.8, 19.3, and 23.5, where α-(1 â†’ 4)-segments had DPs of 3, 6, and 9, respectively. IMS exhibited considerably higher water solubility than maltodextrin because of the α-(1 â†’ 6)-segment and an identical resistance to thermal degradation as short dextran. Interaction of IMS with a fluorescent probe of 2-p-toluidinylnaphthalene-6-sulfonate demonstrated that IMS was more hydrophobic than maltodextrin, where the degree of hydrophobicity increased as DP of α-(1 â†’ 4)-segment increased (9 > 6 > 3). Fluorescent pyrene-estimating polarity of IMS was found to be similar to that of methanol or 1-butanol. The bifunctional IMS enhanced the water solubility of quercetin-3-O-glucoside and quercetin: the solubilization of less-soluble bioactive substances is beneficial in carbohydrate industry.

Heavy oil exposure suppresses antiviral activities in Japanese flounder Paralichthys olivaceus infected with viral hemorrhagic septicemia virus (VHSV).

A combined treatment of heavy oil (HO) exposure and virus infection induces increased mortality in Japanese flounder (Paralichthys olivaceus). In this study, we addressed how HO exposure affects the immune system, especially antiviral activities, in Japanese flounder. The fish were infected with viral hemorrhagic septicemia virus (VHSV), followed by exposure to HO. We analyzed virus titers in the heart and mRNA expression in the kidney of surviving fish. The virus titers in fish exposed to heavy oil were higher than the threshold for onset. The results suggest that HO exposure may allow the replication of VHSV, leading to higher mortality in the co-treated group. Gene-expression profiling demonstrated that the expression of antiviral-activity-related genes, such as those for interferon and apoptosis induction, were lower in the co-treated group than in the group with VHSV infection only. These results helped explain the high virus titers in fish treated with both stressors. Thus, interferon production in the virus-infected cells and apoptosis induction by natural killer cells worked normally in the VHSV-infected fish without HO exposure, but these antiviral activities were slightly suppressed by HO exposure, possibly leading to extensive viral replication in the host cells and the occurrence of VHS.

High-endurance micro-engineered LaB6 nanowire electron source for high-resolution electron microscopy.

The size tunability and chemical versatility of nanostructures enable electron sources of high brightness and temporal coherence, both of which are important characteristics for high-resolution electron microscopy1-3. Despite intensive research efforts in the field, so far, only conventional field emitters based on a bulk tungsten (W) needle have been able to yield atomic-resolution images. The absence of viable alternatives is in part caused by insufficient fabrication precision for nanostructured sources, which require an alignment precision of subdegree angular deviation of a nanometre-sized emission area with the macroscopic emitter axis4. To overcome this challenge, in this work we micro-engineered a LaB6 nanowire-based electron source that emitted a highly collimated electron beam with good lateral and angular alignment. We integrated a passive collimator structure into the support needle tip for the LaB6 nanowire emitter. The collimator formed an axially symmetric electric field around the emission tip of the nanowire. Furthermore, by means of micromanipulation, the support needle tip was bent to align the emitted electron beam with the emitter axis. After installation in an aberration-corrected transmission electron microscope, we characterized the performance of the electron source in a vacuum of 10-8 Pa and achieved atomic resolution in both broad-beam and probe-forming modes at 60 kV beam energy. The natural, unmonochromated 0.20 eV electron energy loss spectroscopy resolution, 20% probe-forming efficiency and 0.4% probe current peak-to-peak noise ratio paired with modest vacuum requirements make the LaB6 nanowire-based electron source an attractive alternative to the standard W-based sources for low-cost electron beam instruments.

Reduced gonadotroph stimulation by ethanolamine plasmalogens in old bovine brains.

Ethanolamine plasmalogens (EPls), unique alkenylacyl-glycerophospholipids, are the only known ligands of G-protein-coupled receptor 61-a novel receptor co-localised with gonadotropin-releasing hormone receptors on anterior pituitary gonadotrophs. Brain EPl decreases with age. Commercial EPl-extracted from the cattle brain (unidentified age)-can independently stimulate FSH secretion from gonadotrophs. We hypothesised that there exists an age-related difference in the quality, quantity, and ability of bovine brain EPls to stimulate bovine gonadotrophs. We compared the brains of young (about 26 month old heifers) and old (about 90 month old cows) Japanese Black bovines, including EPls obtained from both groups. Additionally, mRNA expressions of the EPl biosynthesis enzymes, glyceronephosphate O-acyltransferase, alkylglycerone phosphate synthase, and fatty acyl-CoA reductase 1 (FAR1) were evaluated in young and old hypothalami. The old-brain EPl did not stimulate FSH secretion from gonadotrophs, unlike the young-brain EPl. Molecular species of EPl were compared using two-dimensional liquid chromatography-mass spectrometry. We identified 20 EPl molecular species of which three and three exhibited lower (P < 0.05) and higher (P < 0.05) ratios, respectively, in old compared to young brains. In addition, quantitative reverse transcription-polymerase chain reaction detected higher FAR1 levels in the POA, but not in the ARC&ME tissues, of old cows than that of fertile young heifers. Therefore, old-brain EPl may be associated with age-related infertility.

Aryl Hydrocarbon Receptor Signaling Is Functional in Immune Cells of Rainbow Trout (Oncorhynchus mykiss).

The arylhydrocarbon receptor (AhR) is an important signaling pathway in the immune system of mammals. In addition to its physiological functions, the receptor mediates the immunotoxic actions of a diverse range of environmental contaminants that bind to and activate the AhR, including planar halogenated aromatic hydrocarbons (PHAHs or dioxin-like compounds) and polynuclear aromatic hydrocarbons (PAHs). AhR-binding xenobiotics are immunotoxic not only to mammals but to teleost fish as well. To date, however, it is unknown if the AhR pathway is active in the immune system of fish and thus may act as molecular initiating event in the immunotoxicity of AhR-binding xenobiotics to fish. The present study aims to examine the presence of functional AhR signaling in immune cells of rainbow trout (Oncorhynchus mykiss). Focus is given to the toxicologically relevant AhR2 clade. By means of RT-qPCR and in situ hybdridization, we show that immune cells of rainbow trout express ahr 2α and ahr 2ß mRNA; this applies for immune cells isolated from the head kidney and from the peripheral blood. Furthermore, we show that in vivo as well as in vitro exposure to the AhR ligand, benzo(a)pyrene (BaP), causes upregulation of the AhR-regulated gene, cytochrome p4501a, in rainbow trout immune cells, and that this induction is inhibited by co-treatment with an AhR antagonist. Taken together, these findings provide evidence that functional AhR signaling exists in the immune cells of the teleost species, rainbow trout.

Structural analysis and reaction mechanism of the disproportionating enzyme (D-enzyme) from potato.

Starch produced by plants is a stored form of energy and is an important dietary source of calories for humans and domestic animals. Disproportionating enzyme (D-enzyme) catalyzes intramolecular and intermolecular transglycosylation reactions of α-1, 4-glucan. D-enzyme is essential in starch metabolism in the potato. We present the crystal structures of potato D-enzyme, including two different types of complex structures: a primary Michaelis complex (substrate binding mode) for 26-meric cycloamylose (CA26) and a covalent intermediate for acarbose. Our study revealed that the acarbose and CA26 reactions catalyzed by potato D-enzyme involve the formation of a covalent intermediate with the donor substrate. HPAEC of reaction substrates and products revealed the activity of the potato D-enzyme on acarbose and CA26 as donor substrates. The structural and chromatography analyses provide insight into the mechanism of the coupling reaction of CA and glucose catalyzed by the potato D-enzyme. The enzymatic reaction mechanism does not involve residual hydrolysis. This could be particularly useful in preventing unnecessary starch degradation leading to reduced crop productivity. Optimization of this mechanism would be important for improvements of starch storage and productivity in crops.

Sulfur(VI) Fluoride Exchange (SuFEx)-Enabled High-Throughput Medicinal Chemistry.

Optimization of small-molecule probes or drugs is a synthetically lengthy, challenging, and resource-intensive process. Lack of automation and reliance on skilled medicinal chemists is cumbersome in both academic and industrial settings. Here, we demonstrate a high-throughput hit-to-lead process based on the biocompatible sulfur(VI) fluoride exchange (SuFEx) click chemistry. A high-throughput screening hit benzyl (cyanomethyl)carbamate (Ki = 8 µM) against a bacterial cysteine protease SpeB was modified with a SuFExable iminosulfur oxydifluoride [RN═S(O)F2] motif, rapidly diversified into 460 analogs in overnight reactions, and the products were directly screened to yield drug-like inhibitors with 480-fold higher potency (Ki = 18 nM). We showed that the improved molecule is active in a bacteria-host coculture. Since this SuFEx linkage reaction succeeds on picomole scale for direct screening, we anticipate our methodology can accelerate the development of robust biological probes and drug candidates.

Dense carbon-nanotube coating scaffolds stimulate osteogenic differentiation of mesenchymal stem cells.

Carbon nanotubes (CNTs) have desirable mechanical properties for use as biomaterials in orthopedic and dental area such as bone- and tooth- substitutes. Here, we demonstrate that a glass surface densely coated with single-walled carbon nanotubes (SWNTs) stimulate the osteogenic differentiation of rat bone marrow mesenchymal stem cells (MSCs). MSCs incubated on SWNT- and multi-walled carbon nanotube (MWNT)-coated glass showed high activities of alkaline phosphatase that are markers for early stage osteogenic differentiation. Expression of Bmp2, Runx2, and Alpl of MSCs showed high level in the early stage for MSC incubation on SWNT- and MWNT-coated surfaces, but only the cells on the SWNT-coated glass showed high expression levels of Bglap (Osteocalcin). The cells on the SWNT-coated glass also contained the most calcium, and their calcium deposits had long needle-shaped crystals. SWNT coating at high density could be part of a new scaffold for bone regeneration.

Reducing the undesirable odor of barley by cooking with superheated steam.

Superheated steam was used to cook barley and the volatile odor compounds and release of odorants from the steamed barley were analyzed. The main odor compounds in cooked barley were aldehydes (hexanal and (E,E)-2,4-decadienal) and acids (acetic acid and hexanoic acid). Compared to ordinary cooked barley, barley cooked by superheated steam had less odorants, and the release of odorants was reduced by almost half. Sensory evaluation revealed that this barley was preferred to ordinary cooked barley, because it had weaker smell and tasted less sour and less bitter. The steaming process steam distils and eliminates some odor compounds, while some water-soluble compounds (mainly acids) are washed away by water during steaming. Therefore, this steam cooking method, applied to barley for the first time here using a comprehensive analysis, improves the acceptability and palatability of this high-quality food rich in dietary fiber.

A novel intracellular dextranase derived from Paenibacillus sp. 598K with an ability to degrade cycloisomaltooligosaccharides.

Paenibacillus sp. 598K produces cycloisomaltooligosaccharides (CIs) in culture from dextran and starch. CIs are cyclic oligosaccharides consisting of seven or more α-(1 → 6)-linked-D-glucose residues. The extracellular enzyme CI glucanotransferase (PsCITase), which is the member of glycoside hydrolase family 66, catalyzes the final stage of CI production and produces mainly cycloisomaltoheptaose. We have discovered a novel intracellular CI-degrading dextranase (PsDEX598) from Paenibacillus sp. 598K. The 69.7-kDa recombinant PsDEX598 does not digest isomaltotetraose or shorter isomaltooligosaccharides, but digests longer ones of at least up to isomaltoheptaose. It also digests oligoCIs of cycloisomaltoheptaose, cycloisomaltooctaose, and cycloisomaltononaose better than it does with megaloCIs of cycloisomaltodecaose, cycloisomaltoundecaose, and cycloisomaltododecaose, as well as an α-(1 → 6)-D-glucan of dextran 40. PsDEX598 is produced intracellularly when culture medium is supplemented with cycloisomaltoheptaose or dextran, but not with isomaltooligosaccharides (a mixture of isomaltose, isomaltotriose, and panose), starch, or glucose. The whole genomic DNA sequence of the strain 598K implies that it harbors two genes for enzymes belonging to glycoside hydrolase family 66 (PsCITase and PsDEX598), and PsDEX598 is the only dextranase in the strain. PsDEX598 does not have any carbohydrate-binding modules (CBMs) and has a low similarity (< 30%) with other family 66 dextranases, and the catalytic amino acids of this enzyme are predicted to be Asp191, Asp303, and Glu368. The strain Paenibacillus sp. 598K appears to take up CI-7, so these findings indicate that this bacterium can degrade CIs using a dextranase within the cells and so utilize them as a carbon source for growth.

Self-Assembly of Amphiphilic Amylose Derivatives in Aqueous Media.

Six amylose derivative (C12CMA) samples with hydrophobic dodecyl ether groups and hydrophilic sodium carboxymethyl groups were synthesized from an enzymatically synthesized amylose for which the weight-average molar mass is 50 kg mol-1 to realize amylose-based amphiphilic polymer micelles. The degree of substitution of hydrophobic (DSC12) and hydrophilic (DSCM) groups ranges between 0.076 and 0.39 and between 0.35 and 1.83, respectively. Static and dynamic light scattering, small-angle X-ray scattering (SAXS), and fluorescence measurements with pyrene as a probe were carried out for the samples in 150 mM aqueous NaCl to characterize the higher-order structure in solution. The fluorescence from pyrene showed that all six samples have hydrophobic environment, while the hydrophobicity tends to increase with rising DSC12. All six samples have high scattering intensity owing to the relatively large concentrated droplets ranging in the hydrodynamic radius from 50 to 110 nm, whereas the weight fraction of such large particles is substantially small except for the highest DSC12 sample. Most polymer chains for relatively low DSC12 of 0.076 were molecularly dispersed with a very small amount of large droplets. The dispersed chain has a slightly smaller helix pitch per residue and a more rigid main chain than those for amylose in dimethyl sulfoxide, suggesting that the amylosic main chain of C12CMA has a helical structure with dodecyl groups at least locally. On the other hand, an anisotropic shaped micelle-like structure is only found for relatively high DSC12 (0.23 and 0.39) samples, which was detected by the SAXS profile at a high scattering vector range. The micelle structure for high DSC12 samples is consistent with the high chain stiffness.

Does local chain conformation affect the chiral recognition ability of an amylose derivative? Comparison between linear and cyclic amylose tris(3,5-dimethylphenylcarbamate).

Coated-type chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) were prepared from three cyclic amylose tris(3,5-dimethylphenylcarbamate) (cADMPC) samples, of which weight-average molar mass (Mw) ranges from 19 to 91 kg mol-1, and from three linear ADMPC samples ranging in Mw from 25 to 90 kg mol-1. CSPs made of cADMPC showed appreciably different chiral separation ability comparing with those for ADMPC with a mixed eluent of n-hexane and 2-propanol. Local conformation plays an important role for the chiral separation taking into account that the local helical structure of cADMPC in dilute solution is extended comparing with ADMPC. Immobilized-type CSPs were also prepared from enzymatically synthesized linear and cyclic amylose samples with 3-(triethoxysilyl)propylcarbamate linkers (ADMPCi and cADMPCi) of which Mw's are in the range from 18 to 130 kg mol-1. When we choose quite high linker contents, CSPs of cADMPCi were fairly close to those of ADMPCi. This suggests that local conformations of ADMPCi and cADMPCi are similar in the stationary phase since they are crosslinked to the other polymer chains with multiple points on the polymer chain.