Investigating the formation and diagnostic value of ω-(o-alkylphenyl)alkanoic acids in ancient pottery.

Long-chain ω-(o-alkylphenyl)alkanoic acids (APAAs) derived from the heating of unsaturated fatty acids have been widely used for the identification of aquatic products in archaeological ceramic vessels. To date, little attention has been paid to the diagnostic potential of shorter chain (< C20) APAAs, despite their frequent occurrence. Here, a range of laboratory and field experiments and analyses of archaeological samples were undertaken to investigate whether APAAs could be used to further differentiate different commodities. The results provide new insights about the conditions for the formation of APAAs and enable the proposition of novel criteria to distinguish different natural products.

Dental caries prevalence as a product of agriculture and subsistence pattern at the Yean-ri site, South Korea.

Yean-ri human skeletal remains from South Korea have been dated to the fourth to seventh century AD. They have morphological similarities to immigrants of the Yayoi period excavated in northern Kyushu and Yamaguchi prefecture in Japan. The overall dental caries prevalence was 8.1% in the Yean-ri skeletal remains, indicating a much lower prevalence than that of most Yayoi immigrant skeletal remains from Japan, although similar to that of the Kofun people (8.3%) in Japan. There was no significant difference in the dental caries prevalence between the males and females of the same age group, but there were differences in the prevalence by age. The late middle age and elderly males and females had significantly higher dental caries prevalence than the early middle age males and females, indicating increased prevalence with age. Root caries prevalence tended to increase in old age. The percentage of root caries increased, accounting for 80% of all caries in Yean-ri human skeletal remains. Agriculture is believed to have arisen approximately 3,000 years ago in Korea. Therefore, agriculture was practiced during this period, but since the Yean-ri tumuli are from coastal areas, their diet may have retained a significant marine component. Additionally, caries prevalence was not very high in Nukdo human remains (ca. 2100-2000 BC) in Korea. We speculate that they maintained subsistence activities suitable for their environment despite their knowledge of agriculture. This hypothesis is supported by differences in the caries prevalence between excavation sites of the Yayoi and Kofun periods in Japan.

A novel disaccharide substrate having 1,2-oxazoline moiety for detection of transglycosylating activity of endoglycosidases.

A disaccharide substrate of Manbeta1-4GlcNAc-oxazoline 2 was designed and synthesized as a novel probe for detection of the transglycosylating activity of endoglycosidases. A regio- and stereoselective transglycosylation reaction of 2 to GlcNAcbeta1-O-pNP or Dns-Asn(GlcNAc)-OH catalyzed by endo-beta-N-acetylglucosaminidase from Mucor hiemalis (Endo-M) and endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae (Endo-A) has been demonstrated for the first time, resulting in the core trisaccharide derivative Manbeta1-4GlcNAcbeta1-4GlcNAcbeta1-O-pNP 8 (or -(Dns)Asn-OH). Interestingly, the transglycosylation proceeds irreversibly; the resulting trisaccharide 8 was not hydrolyzed by Endo-M and Endo-A. Based on these results, a new mechanism including an oxazolinium ion intermediate has been proposed for the endoglycosidase-catalyzed hydrolysis or transglycosylation.

Determination of the degree of acetylation of chitin/chitosan by pyrolysis-gas chromatography in the presence of oxalic Acid.

A new method to determine directly and rapidly the degree of acetylation of chitin/chitosan was developed based on reactive pyrolysis-gas chromatography in the presence of an oxalic acid aqueous solution. The degree of acetylation was precisely evaluated on the basis of peak intensities of the characteristic products such as acetonitrile, acetic acid, and acetamide originating from the N-acetyl group of N-acetyl-d-glucosamine units of chitin/chitosan. The observed values were in good agreement with those obtained by (1)H NMR and the other methods. Moreover, the proposed technique was applicable to any kinds of chitin/chitosan samples over the whole range of acetylation including insoluble chitin/chitosan and perfectly acetylated artificial chitin having higher crystallinity to which (1)H NMR had been inapplicable.

Chemical synthesis of cellulose and cello-oligomers using a hydrolysis enzyme as a catalyst.

Regio- and stereo-selective synthesis of polysaccharides and oligosaccharides has been achieved by using glycosyl fluorides as substrates for cellulases. This methodology has successfully been applied to the first synthesis of cellulose via a non-biosynthetic pathway as well as to a selective preparation of cello-oligosaccharides and unnatural oligosaccharides. Using the enzymatic polymerization, it is possible to control the relative direction (parallel or anti-parallel) of each glucan chain in the synthetic cellulose in vitro. Based on these results, a new concept of 'allos-selectivity' in polymer synthesis has been proposed.

[Surgical and botulinum toxin treatment in two cases of abnormal retinal correspondence-exotropia with congenital homonymous hemianopsia].

We report 2 unusual cases of congenital occipital hemianopsia associated with abnormal retinal correspondence (ARC)-exotropia. Two Japanese males, 25 and 28 years of age, visited our hospital for surgical correction of manifest exotropia with dissociated vertical deviation and overaction of the superior oblique muscle. Visual field examination demonstrated homonymous hemianopsia with approximately 5 to 10 degrees of macular sparing. Visually evoked potential examination showed small amplitude similar to dissociated vertical deviation patients in all half-field stimulation. Electrooculogram examination demonstrated defective pursuit to the ipsilateral side. Some investigators have speculated that progressive exotropia compensates for homonymous hemianopsia and is a rare contraindication for strabismus surgery. To confirm the deterioration of motor and visual functions before surgery in these patients, we tried injections of botulinum A type toxin into the lateral rectus muscle ipsilateral to the hemianopsia. Contrary to the hypothesis, our patients had no change in their binocular visual fields and visual function. Finally, we performed recession of the lateral rectus muscle, so that both patients were satisfied with their ocular alignment, with no marked change of visual behavior.

[Pattern-reversal visual evoked potentials dissociated vertical deviation].

We recorded pattern-reversal visual evoked potentials (P-VEP) from dissociated vertical deviation (DVD) patients to evaluate the sensory system abnormalities in DVD. 91 DVD patients with good visual acuity were studied. Normal subjects and horizontal strabismic patients without DVD were compared for evaluation. Transient and steady state P-VEPs were recorded from three EEG electrodes placed on the posterior scalp. Half-field checker-board reversal stimulation was applied to stimulate monocular temporal retina and responses from right and left hemispheres were also compared for evaluation. Paradoxical lateralization was observed in all normal subjects. Abnormal P-VEPs were observed in 4 of 20 (20%) horizontal strabismic patients without DVD when employing the transient stimulation method and in 2 of 8 (25%) when using steady state stimulation. Abnormal P-VEPs were observed in 31 of 67 (46.3%) DVD patients, with the transient stimulation method and in 20 of 25 (80.0%) DVD patients with the steady state stimulation method. The abnormalities were various and diverse. Our observations indicate that DVD patients frequently have an abnormal sensory system detected by P-VEP, and DVD might be a complex and multi-origin condition involving both sensory and motor systems.

Assembly of synthetic cellulose I.

Cellulose microfibrils with an electron diffraction pattern characteristic of crystalline native cellulose I have been assembled abiotically by means of a cellulase-catalyzed polymerization of beta-cellobiosyl fluoride substrate monomer in acetonitrile/acetate buffer. Substantial purification of the Trichoderma viride cellulase enzyme was found to be essential for the formation of the synthetic cellulose I allomorph. Assembly of synthetic cellulose I appears to be a result of a micellar aggregation of the partially purified enzyme and the substrate in an organic/aqueous solvent system favoring the alignment of glucan chains with the same polarity and extended chain conformation, resulting in crystallization to form the metastable cellulose I allomorph.

A facile enzymatic synthesis of cellooligosaccharide derivatives using beta-lactosyl fluoride.

A convenient method for the preparation of cellooligosaccharide derivatives has been developed that uses beta-lactosyl fluoride as the glycosyl donor. The reaction consists of the following enzymatic processes; (1) a cellulase-catalyzed regio- and stereo-selective lactosylation of a beta-cellobioside as the glycosyl acceptor, utilizing the transglycosylating ability of an enzyme-substrate complex formed from beta-lactosyl fluoride and cellulase; (2) beta-D-galactosidase-catalyzed regioselective cleavage of the terminal D-galactose unit from the lactosylated product, giving rise to a beta-cellotrioside derivative. A cellotetraoside derivative has successfully been prepared in a stereo- and regio-selective manner by repeating these enzymatic reactions and using the resulting beta-cellotrioside as starting material.