EnterohemorrhagicEscherichia coli O157:H7 possesses somatic (O) antigen identical with that ofSalmonella O301

The O antigen of enterohemorrhagicEscherichia coli O157:H7 is identical with that ofSalmonella O30₁ and is also related toSalmonella O30₁30₂ in an a-a, b type of relationship.     

Absolute configurations of pittosporatobiraside A and B from Pittosporum tobira

The absolute configuration at C-12 of pittosporatobiraside A and B isolated from the leaves of Pittosporum tobira was determined to be S on the basis of the exciton chirality of their dibenzoate derivative. The structures of the two glycosides were thus established to be (1S,9S,10S,11S,12S,14R,16R)-12-[(Z)-2-methyl-1-oxo-2-butenyl]-6,14-dimethyl-2-methylene-9-(1-methylethyl)-15,17-dioxatricyclo[8.7.0.0^11,16]heptadec-5-en-13-one and (1S,9S,10S,11S,12S,14R,16R)-12-(3-methyl-1-oxo-2-butenyl)-6,14-dimethyl-2-methylene-9-(1-methylethyl)-15,17-dioxatricyclo [8.7.0.0^11,16]heptadec-5-en-13-one, respectively.     

Binding sites for epidermal growth factor in nuclear fraction from rat liver

Binding sites for mouse epidermal growth factor (EGF) were observed in purified nuclear fraction from rat liver. The binding data yielded a curvilinear Scatchard plot which was decomposed into two binding components with different binding affinities. The binding component with higher affinity (Kd approximately 10(-10) M) represented approximately 15% of the total binding, while the high affinity binding sites were less than 5% of the total in the microsomes. The ligand-dependent autophosphorylation, one of the characteristic features of EGF receptor in the plasma membrane, was not observed at the site of the receptor (170 KDa) in the nuclear fraction. The binding characteristics for EGF fluctuated during the course of liver regeneration after partial hepatectomy; the binding capacity in the nuclear fraction increased in contrast to the decrease in the microsomes. However, the binding sites in the nuclear fraction obtained in the early period after partial hepatectomy consisted only of low affinity ones.     

Receptor recycling: liberation of glucocorticoid receptors from liver nuclei in vitro

Dynamics of the steroid receptors seems to be the consequence of receptor recycling. In the present study, as a clue to elucidate the mechanism of receptor recycling, factors which affect the rate of liberation of nuclear bound 3H-glucocorticoids were examined in vitro. Among the factors examined, NAD, NADPH, cAMP and p-nitrophenyl phosphate accelerated the liberation of radioactivity from nuclei in a temperature-dependent manner when added to the incubation mixture. The presence of a large amount of unlabeled dexamethasone (Dex) did not modify the rate of liberation. From these results, it was concluded that the metabolism of ligand bound to the receptor is not a necessary step in the liberation of receptor from nuclei. These agents did not influence the binding process of 3H-Dex-receptor complex to DNA-cellulose. Therefore the stimulation of receptor release does not seem to be mediated by reducing the binding affinity between nuclei and receptor complexes. The liberated radioactivity was eluted on a Sephadex G-100 column in the void volume and in macromolecule-unbound fractions. In both fractions, the majority of the radioactivity comigrated with authentic glucocorticoids on thin-layer chromatography.     

Effects of a dietary deficiency in calcium on growth and calcium uptake from the aquatic environment in the goldfish, Carassius auratus

1. Young goldfish, Carassius auratus, were fed a calcium-deficient diet for 8 or 56 days and then their net uptake of calcium from the aquatic environment was examined using 45Ca. 2. They showed normal growth and the normal level of plasma calcium in both experiments. 3. In the short-term experiment, no dietary effect was found in the uptake of environmental calcium. In the long-term experiment, however, the rate of uptake was significantly stimulated by 18%. 4. The results indicate the presence of a compensatory action in calcium uptake between dietary and aquatic sources.     

Age-dependent aluminum accumulation in the human aorta and cerebral artery

The purpose of this study was to determine the extent of aluminum (Al) accumulation in the human aorta and cerebral arteries. The Al contents in the aortae and in the cerebral arteries from 23 human subjects was determined by inductively coupled plasma atomic emission spectrophotometry (ICP-AES). The subjects' age range was 45–99-yr-old; 15 of the subjects were males and 8 were females. Al was detected in twelve aortae and in six cerebral arteries, when the entire specimen was analyzed. Two specimens where Al was found in the cerebral arteries contained no Al in the aorta. No relationship to the subject's sex was found. When related to age, two groups were established. Group L (45–75 yr old) and group H (>75 yr old), which exhibited aortal Al concentrations of 33.3 and 72.7%, respectively. When the aortic wall was dissected into the tunica intima, media, and adventitia, Al was found mainly in the tunica media. In the aorta, significant relationships were found between Al and phosphorus (P) levels (r=0.801,p<0.01) and between Al and calcium (Ca) (r=0.661,p<0.05). We have concluded that Al accumulation is age-dependent and that it occurs both in the aorta and in the cerebral artery. In the aorta, accumulation occurs mainly in the tunica media. Both P and Ca appear to enhance aortal Al accumulation.     

Nitric Oxide Induces Phytoalexin Accumulation in Potato Tuber Tissues

We investigated whether nitric oxide (NO) radical could inducephytoalexin production. Treatment of potato tuber tissues with1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene (NOC-18), anNO-releasing compound, induced the accumulation of the potatophytoalexin rishitin. This induction was inhibited by carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide(carboxy-PTIO), an NO-specific scavenger, or by Tiron, a radicalscavenger, suggesting a phytoalexin inducing activity for NO. (Received December 7, 1995; Accepted January 4, 1996)     

Cloning and Characterization of the Murine GPI Anchor Synthesis GenePigf,a Homologue of the HumanPIGFGene

Many eukaryotic proteins are bound to the plasma membrane via a glycosylphosphatidylinositol (GPI) anchor. Its core backbone, which is conserved in different organisms, is synthesized in the endoplasmic reticulum by the sequential addition of glycan components to phosphatidylinositol. One of the human GPI synthesis genes,PIGF(phosphatidylinositol glycan complementation class F), which is involved late in the synthesis pathway, has been cloned. In this study, we isolated complementary and genomic clones ofPigf,a murine counterpart ofPIGF. Pigfencodes a 219 amino acid protein that complements a class F mutation. ThePigfgene consists of six exons spanning 30 kb and was mapped to chromosome 17 at 17E4–E5. These features are very similar toPIGF,thus demonstrating the interspecies conservation of structure, function, gene organization, and genetic locus between these GPI synthesis genes. The results also extend a region in murine distal chromosome 17 that is syntenic to human chromosome 2p16–p22.     

Lipopolysaccharide Isolated from a New O-Antigenic Form (O13) of Vibrio parahaemolyticus

The chemical properties of a lipopolysaccharide (LPS) isolated from a new O-antigenic form (O13) of Vibrio parahaemolyticus were investigated. The LPS contained glucose, galactose, L -glycero-D -manno-heptose and glucosamine. 2-Keto-3-deoxy-octonate (KDO) was not detected in the LPS by the periodate-thiobarbituric acid test (Weissbach's reaction) under conventional hydrolysis conditions. Instead, phosphorylated KDO (X1 and X2) was found in its strong-acid hydrolysate. This sugar composition was identical to that of V. parahaemolyticus O3, O5 and O11 LPS, indicating that, based on the sugar composition, O13 LPS belongs to Chemotype III to which O3, O5 and O11 belong. In addition, structural study demonstrated the presence of KDO 4-phosphate in its inner-core region.     

Isolation and characterization of cDNA clones for castration-induced mRNAs in the rat ventral prostate.

To identify gene products involved in castration-induced involution of the rat ventral prostate, we constructed a subtraction cDNA library of the ventral prostate from rats castrated for 48 h. The library was screened with subtracted cDNA probes enriched for sequences with a low copy number expressed in intact or castrated rats. As a result of differential screening, 48 cDNA clones representing 10 different induced mRNAs were isolated. The time course of these mRNA inductions after castration was examined. Within the first 24 h after castration, the level of mRNAs for these cDNA clones was significantly increased and it reached its peak by 48-72 h after castration. Although mRNAs for these cDNA clones were expressed in various tissues from intact rats, an increase in mRNA as a response to castration was observed only in the ventral prostate. Partial sequence analyses of the 10 cDNA clones indicate that three cDNA clones represent rat glutathione S-transferase Yb-1, Yb-2 and Yb-3 subunit mRNA sequences, but for others respective homologues could not be found in a search of the GenBank database (release 67).