Formation of spray-dried powder of S-adenosyl-L-methionine

S-Adenosyl-L -methionine (SAM) is an essential metabolite in all living organisms. In clinical research, SAM has also been suggested as a chemotherapeutic agent in various diseases. The main problem of SAM is its instability at high temperatures, at neutral and alkaline pH, and in the presence of humidity. SAM retention in spray-dried powder was determined under various conditions of spray-drying. The highest SAM retention was obtained when maltodextrin (dextrose equivalent, DE, of 25) was used as the carrier solid with the SAM feed liquid at pH 4.0. The water content in the powder had a significant effect on the stability of SAM. SAM powder with lower water content exhibited higher stability.     

Identification of two novel amyloid A protein subsets coexisting in an individual patient of AA-amyloidosis

Amyloid A protein (AA), the major fibril protein in AA-amyloidosis, is an N-terminal cleavage product of the precursor protein, serum amyloid A (SAA). Using mass spectrometry and amino-acid sequencing, we identified and characterized two novel AA protein subsets co-deposited as amyloid fibrils in an patient having AA-amyloidosis associated with rheumatoid arthritis. One of the AA proteins corresponded to positions 2–76 (or 75) of SAA2α and the other corresponded to positions 2–76 (or 75) of known SAA1 subsets, except for position 52 or 57, where SAA1α has valine and alanine and SAA1β has alanine and valine in position 52 and 57, respectively, whereas the AA protein had alanine at the both positions. Our findings (1), demonstrate that not only one but two SAA subsets could be deposited together as an AA-amyloid in a single individual and (2), support the existence of a novel SAA1 allotype, i.e., SAA1^52,57Ala.     

Physical Characterization of the Chromosomal DNA of the Yeast Saccharomyces exiguus

The number of chromosomes in the yeast Saccharomyces exiguuswas determined to be thirteen by two-dimensional pulsed-fieldgel electrophoresis. The thirteen chromosomes ranged in DNAsize from 520 to 2,600 kbp, with a total length of approximately14 Mbp. Numbers I to XIII were assigned to the chromosomes indecreasing order of DNA length. Southern hybridization analysisusing total DNAs from S. exiguus and S. cerevisiae as probesshowed that there was no significant homology between the chromosomalDNAs of the two species, except in the case of the chromosomalDNA that included rDNA. When rDNA and genes LEU2, TRP1, URA3and HO of S. cerevisiae were used as hybridization probes, itwas apparent that S. exiguus had DNA sequences homologous tothe rDNA and to the LEU2 and HO genes. In S. exiguus, rDNA-likeand LEU2-like DNAs were located on chromosomes I and IX, respectively,and HO-like DNA was located on chromosome VI or VII. (Received May 17, 1993; Accepted July 15, 1993)     

Synthesis of D-cysteine from 3-chloro-D-alanine and hydrogen sulfide by 3-chloro-D-alanine hydrogen chloride-lyase (deaminating) of Pseudomonasputida

Synthesis of D-cysteine from 3-chloro-D-alanine and hydrogen sulfide is catalyzed by highly purified 3-chloro-D-alanine hydrogen chloride-lyase from $\text{Pseudomonas}\text{putida}$. The synthetic reaction proceeds optimally at pH 8.5, as a function of enzyme concentration and incubation time. The enzymatically synthesized D-cysteine was isolated from the large scale reaction mixture and identified by physicochemical means.     

Crystal structure of pantoate kinase from Thermococcus kodakarensis

The coenzyme A biosynthesis pathways in most archaea involve two unique enzymes, pantoate kinase and phosphopantothenate synthetase, to convert pantoate to 4′-phosphopantothenate. Here, we report the first crystal structure of pantoate kinase from the hyperthermophilic archaeon, Thermococcus kodakarensis and its complex with ATP and a magnesium ion. The electron density for the adenosine moiety of ATP was very weak, which most likely relates to its broad nucleotide specificity. Based on the structure of the active site that contains a glycerol molecule, the pantoate binding site and the roles of the highly conserved residues are suggested.     

Microbiological Synthesis of d-Cysteine and an Analogue

A biofertilizer, showing antagonistic activity against potato common scab in pot tests, was produced from swine feces with a newly isolated strain, CH-33, identified as Streptomyces albidoflavus. This strain characteristically grew on fresh swine feces at 20~35°C without sterili-zation or any additives, and produced an antibiotic substance against Streptomyces scabies, the common scab-pathogen, during composting. The addition of the biofertilizer at from 0.1 g to 1.6 g total nitrogen (N) per 600 g humic volcanic ash soil in a pot did not inhibit the growth of Brassica rapa var. perviridis but increased it, even at the highest nitrogen content tested. Common scab was completely inhibited when the biofertilizer was added at 0.1 g to 1.6g as nitrogen (N) per 4 kg of scab-infected soil in a pot. Thus a biofertilizer suppressing plant pathogenic microorganisms was developed.     

DNA Inversion Regulates Outer Membrane Vesicle Production in Bacteroides fragilis

Phase changes in Bacteroides fragilis, a member of the human colonic microbiota, mediate variations in a vast array of cell surface molecules, such as capsular polysaccharides and outer membrane proteins through DNA inversion. The results of the present study show that outer membrane vesicle (OMV) formation in this anaerobe is also controlled by DNA inversions at two distantly localized promoters, IVp-I and IVp-II that are associated with extracellular polysaccharide biosynthesis and the expression of outer membrane proteins. These promoter inversions are mediated by a single tyrosine recombinase encoded by BF2766 (orthologous to tsr19 in strain NCTC9343) in B. fragilis YCH46, which is located near IVp-I. A series of BF2766 mutants were constructed in which the two promoters were locked in different configurations (IVp-I/IVp-II = ON/ON, OFF/OFF, ON/OFF or OFF/ON). ON/ON B. fragilis mutants exhibited hypervesiculating, whereas the other mutants formed only a trace amount of OMVs. The hypervesiculating ON/ON mutants showed higher resistance to treatment with bile, LL-37, and human β-defensin 2. Incubation of wild-type cells with 5% bile increased the population of cells with the ON/ON genotype. These results indicate that B. fragilis regulates the formation of OMVs through DNA inversions at two distantly related promoter regions in response to membrane stress, although the mechanism underlying the interplay between the two regions controlled by the invertible promoters remains unknown.     

Exposure and risk assessment of 1,3-butadiene in Japan

1,3-Butadiene is on the list of Substances Requiring Priority Action published by the Central Environmental Council of Japan in 1996. Emission of 1,3-butadiene has been controlled by a voluntary reduction program since 1997. Although the industrial emission of 1,3-butadiene in Japan has decreased in recent years, primarily due to a voluntary industrial emissions reduction program, the risks of exposure to it remain largely unknown. We assessed the risks and consequences of exposure to 1,3-butadiene on human health. A remarkable advantage of our risk assessment approach is the detailed assessment of exposure. Previously, we developed two different models that can be applied for the assessment of exposure: the first, the AIST-ADMER model estimates regional concentration distributions, whereas the second, the METI-LIS model estimates concentration distributions in the vicinity of factories. Both models were used for the assessment of exposure to 1,3-butadiene. Using exposure concentration and carcinogenic potency determined and reported by Environment Canada and Health Canada, we evaluated the excess lifetime cancer risk for persons exposed to 1,3-butadiene over the course of a lifetime. The results suggested that the majority of the population in Japan has an excess lifetime cancer risk of less than 10(-5), whereas a small number of people living close to industrial sources had a risk of greater than 10(-5). The results of the present assessment also showed that 1,3-butadiene in the general environment originates primarily from automobile emissions, such that a countermeasure of reducing emissions from cars is expected to be effective at reducing the total cancer risk among Japanese. On the other hand, individual risks among a population living in the vicinity of certain industrial sources were found to be significantly higher than those of the population living elsewhere, such that a reduction in emissions from a small number of specific industrial sources should be realized in order to reduce the high level of individual risk. Based on the results of our assessment, the Industrial Structure Council of the Ministry of Economy, Trade and Industry (METI) in Japan decided to announce that the voluntary reduction program had been successful, and that emissions reductions should no longer be targeted across all industries in general, but instead that such reductions should be carried out in a small number of selected factories that emit excessively large amounts of emissions.