Molecular basis for subtypic differences of the “a” subunit of coagulation factor XIII with description of the genesis of the subtypes

The “a” subunit of human coagulation factor XIII (F13A) exhibits genetic polymorphism defined by four common alleles, F13A*1A, *1B, *2A, and *2B. We have previously suggested on the basis of the isoelectric focusing patterns of the four allele products that point mutations at two separate sites and one intragenic crossing over might be involved in the genes of F13A polymorphism. Here, we report nucleotide substitutions associated with F13A polymorphism. A C/T transition of the second nucelotide of codon 564 in exon 12 is responsible for the difference between F13A*1A and *1B and that between F13A*2A and *2B, and a set of two base changes in codons 650 and 651 in exon 14 leads to the differences between F13A*1A and *2A and those between F13A*1B and *2B. The four combinations of the point mutations at the two exons thus correspond to the four alleles, two of which were generated by the point mutations from ancestral monomorphic gene. The results suggest strongly that intragenic crossing over must be involved in the genesis of the fourth allele. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods discriminating these base changes in exons 12 and 14 are also presented.     

Effects of alginates on the ingestion and excretion of cholesterol in the rat

The effects of three forms of alginate (free acid, sodium and calcium salts) on ingestion and excretion of cholesterol in the rat were studied. For two weeks, Male Sprague-Dawley rats were fed a cholesterol-rich diet containing 3% alginate from the brown alga Ascophyllum nodosum. The food efficiency of the three types of alginate was: Na-alginate > Ca-alginate > alginic acid. A significant increase in the weight of cecum was also observed in alginate diets. Alginate was not effective in preventing the elevation of serum total cholesterol levels, although irregularly changing patterns were observed. The cholesterol level of liver showed a tendency to decrease with alginate feeding, while fecal excretion of cholesterol increased.     

Cloning and nucleotide sequence of fosfomycin biosynthetic genes of Streptomyces wedmorensis

The biosynthetic pathway for production of the antibiotic fosfomycin by Streptomyces wedmorensis consists of four steps including the formation of a C-P bond and an epoxide. Fosfomycin production genes were cloned from genomic DNA using S. wedmorensis mutants blocked at different steps of the biosynthetic pathway. Four genes corresponding to each of the biosynthetic steps were found to be clustered in a DNA fragment of about 5 kb. Nucleotide sequencing of a large fragment revealed the presence of ten open reading frames, including the four biosynthetic genes and six genes with unknown functions.     

Conversion of Ulva fronds to a hatchery diet for Artemia nauplii utilizing the degrading and attaching abilities of Pseudoalteromonas espejiana

An algal suspension containing protoplasmic detritus [termed, single cell detritus (SCD)] was prepared from freeze-dried fronds of Ulva and its dietary value to Artemia nauplii was tested after size fractionation. The dissolved fraction (<0.22 μm) ofthe Ulva suspension contained ca. 48% of theoriginal protein in the Ulva, but had no dietaryvalue to Artemia, which is a suspension feeder. In contrast, the fraction passing through a 100-μm meshand containing SCD of 2–14 μm in diameter, contributedto the survival of Artemia. The fraction remaining on the 100 μm mesh was further incubated with and without the bacterium Pseudoalteromonas espejiana strain AR06 FERM BP-5024. The bacterium degraded Ulva forming new SCD over 10⁶ mL ^-1 level as rapidly as by 16 h of incubation. The dietary value of Ulva for Artemia growth was elevated over four times by the incubation. The protein content of the SCD was approximately doubled by the attaching of bacteria, suggesting the enhanced Artemia growth is attributable to the combined effect of the SCD and the bacteria. Development of a hatchery diet from Ulva , a resource with a low commercial value, is suggested utilizing the degrading and attaching ability of P. espejiana. This revised version was published online in August 2006 with corrections to the Cover Date.     

Germitorosone and methylgermitorosone,two hydroanthracene derivatives from seedlings of Cassia torosa

Two new yellow pigments, germitosone and methylgermitorosone, were isolated from the seedling of Cassia torosa. The structures of these substances were established as 3,7 dimethyl - 6 - methoxy - 1 - oxo - 2,3,8,9 - tetrahydroxy - 1,2,3,4 - tetrahydroanthracene and 6,9 dimethoxy - 3,7 - dimethyl - 1 - oxo - 2,3,8 - trihydroxy - 1,2,3,4 - tetrahydroanthracene respectively.     

A new prolyl hydroxylase acting on poly-L-proline, from suspension cultured cells of Vinca rosea

A new prolyl hydroxylase having a novel substrate specificity was isolated from the suspension-cultured cells of Vinca rosea. This enzyme was solubilized with 0.05 M Tris-HCl buffer (pH 7.4) containing 0.1% Triton X-100, 0.3 M NaCl and 0.5 mM beta-mercaptoethanol from the membrane fractions of the cells, and was partially purified by (NH4)2SO4 fractionation and DEAE-Sephadex A-50 column chromatography. The enzyme preparation was found to require O2, Fe2+, ascorbate, alpha-ketoglutarate and poly-L-proline to attain maximum activity. The plant enzyme does not hydroxylate free proline and di-, tri- and tetra-L-proline, but hydroxylates octa-L-proline and poly-L-proline (Mr greater than 2000). Model peptides of unhydroxylated collagen, (Pro-Pro-Gly)5 and (Pro-Pro-Gly)10 are poor substrates for the plant enzyme. This means that the plant enzyme has a novel substrate specificity in regard to peptidyl substrate, and this differs from vertebrate prolyl hydroxylase, proline,2-oxoglutarate dioxygenase (prolyl-glycyl-peptide, 2-oxoglutarate: oxygen oxidoreductase, EC 1.14.11.2).