A novel MHC class I-related molecule expressed on mouse thymic stroma cells and mature lymphocytes

A monoclonal antibody (mAb) TP-3 has been established by immunizing rats with the BALB/c mouse thymic epithelial cell line TEL-2. The TP-3 antigen is expressed on stroma cells of thymus, spleen, and lymph node in syngeneic BALB/c mice (H-2 ^d ). This antigen is also expressed at a low level on the cell surface of immature thymocytes, and at a high level on mature T and B cells. In allogeneic mice such as C57BL/6 (H-2 ^b ) or C3H (H-2 ^k ), no cells expressed the TP-3 antigen. Using H-2 congenic mice, reactivity with mAb TP-3 was found to map to a region of H-2D ^d L ^d or between D ^d and Qa, suggesting that TP-3 is a major histocompatibility complex (MHC) class I antigen. However, immunoprecipitation analysis indicated that this antigen is not identical to the classical mouse class I molecules in terms of molecular size, antigenicity, and tissue distribution.     

Effects of chemically defined tannins on poly (ADP-ribose) glycohydrolase activity.

Three classes of chemically defined tannins, gallotannins, ellagitannins and condensed tannins were examined for their inhibitory activities against purified poly (ADP-ribose) glycohydrolase. Ellagitannins showed higher inhibitory activities than gallotannins. In contrast, condensed tannins, which consist of an epicathechin gallate (ECG) oligomer without a glucose core were not appreciably inhibitory. Kinetic analysis revealed that the inhibition of ellagitannins was competitive with respect to the substrate poly(ADP-ribose), whereas gallotannins exhibited mixed-type inhibition. These results suggest that conjugation with glucose of hexahydroxy-diphenoyl (HHDP) group, which is a unique component of ellagitannins, potentiated the inhibitory activity, and that the structure of ellagitannins may have a functional domain which competes with poly(ADP-ribose) on the poly(ADP-ribose) glycohydrolase molecule.     

Tissue culture response of Beta germplasm: callus induction and plant regeneration

Callus cultures of 18 sugarbeet (Beta vulgaris) lines, two accessions of B. maritima and a B. macrocarpa accession were initiated from aseptically germinated seeds. Plant regeneration through organogenesis was obtained either on MS or B5 medium containing various concentrations and combinations of naphthaleneacetic acid (NAA), 6-benzylaminopurine (BAP), 2,3,5-triiodobenzoic acid (TIBA) and abscisic acid (ABA). Genotypes differed in their abilities of callus formation and regeneration: seven out of 18 sugarbeet lines, and an accession of B. maritima were capable of regenerating plantlets. Our data also indicated that 2 M TIBA promoted morphogenesis from callus culture in the presence of 5 M BAP.     

Identification of (Na,K)ATPase inhibitor in brine shrimp,Artemia salina,as long-chain fatty acids

Summary An inhibitory activity to (Na,K)ATPase was found in cell extracts of the brine shrimp, Artemia salina, irrespective of its developmental stages. Organic solvent extraction together with gas chromatographic analysis reveals that the inhibitory activity is due to long-chain, non-esterified fatty acids and their derivatives. Unsaturated fatty acids, especially with cis-configuration, are more effective in inhibition than saturated ones.Abbreviations ATPase adenosine triphosphatase - EDTA ethylenediamine-tetraacetate - TLC thin-layer chromatography     

Alterations in cardiac function and subcellular membrane activities after hypervitaminosis D3

The present study was designed to induce massive accumulation of calcium in the myocardium and to evaluate the effect of calcium overload on myocardial contractile function and biochemical activity of cardiac subcellular membranes. Rats were treated with an oral administration of 500,000 units/kg of vitamin D₃ for 3 consecutive days, and their hearts were sampled on the 5th day for biochemical analysis. On the 4th and 5th days, heart rate, mean aortic pressure, left ventricular systolic pressure and left ventricular dP/dt were significantly lowered in vitamin D₃-treated rats, demonstrating the existence of appreciable myocardial contractile dysfunction. Marked increases in the myocardial calcium (67-fold increase) and mitochondrial calcium contents (24-fold increase) were observed by hypervitaminosis D3. Mitochondrial oxidative phosphorylation and ATPase activity were significantly reduced by this treatment. A decline in sarcolemmal Na⁺, K⁺-ATPase activity was also observed, while relatively minor or insignificant changes in calcium uptake and ATPase activities of sarcoplasmic reticulum were detectable. Electron microscopic examination revealed calcium deposits in the mitochondria after vitamin D₃ treatment. The results suggest that hypervitaminosis D₃ produces massive accumulation of calcium in the myocardium, particularly in the cardiac mitochondrial membrane, which may induce an impairment in the mitochondrial function and eventually may lead to a failure in the cardiac contractile function.     

The gene for retinal rod 33-kDa protein is on mouse chromosome 1, near Lamb2.

A water-soluble protein (called "33-kDa protein") that exhibits light-dependent phosphorylation has been shown to be a major protein of mammalian rod photoreceptors. Although the function of this protein is unknown, it has been implicated in the biochemical cascade mediating the rod visual response. Using a retinal cDNA from the rat and somatic cell hybrids, we have mapped the gene corresponding to this protein to mouse Chromosome 1 and, by analyzing the progeny of an intersubspecific backcross, have positioned it near Lamb2 (the beta 2 chain of laminin). We have designated the gene Rpr-1 (rod photoreceptor protein-1).     

Evidence for the existence of cytoskeleton-bound polysomes in plants.

When conventional, high ionic strength buffers were used for the isolation of polysomes from pea plants, less than 20% were retained in the detergent-insoluble pellet. Reducing Tris, K+ and Mg++ to 10 mM increased retention to 70%, and when a new, microfilament-stabilizing buffer was used, retention increased to 80%. Conditions which favoured polysome pelleting at lower g forces permitted the retention of actin in the pellet. The data are consistent with the hypothesis that higher plants, like animals, contain cytoskeleton-(actin)-bound polysomes.     

Immunochemical and histochemical studies on a phosphonoglycosphingolipid, SGL-II, isolated from the sea gastropod Aplysia kurodai

Antiserum was raised against 3-O-MeGal beta 1----3GalNAc alpha 1----3[6' -O-(2-aminoethylphosphonyl)Gal alpha 1----2 (2-aminoethylphosphonyl----6)Gal beta 1----4Glc beta 1----1Ceramide (SGL-II) isolated from the skin of a mollusc, Aplysia kurodai. This antiserum reacted with SGL-II and other phosphonoglycosphingolipids of Aplysia such as SGL-I', F-21, and some minor glycolipids on TLC plates, but it did not react with ganglioside or globoside. The sugars recognized were 3-O-methylgalactose at the non-reducing end and galactose at the branched chain of the glycolipids. One membrane glycoprotein (Mr 280,000) reacted strongly, and some other proteins reacted weakly with the antiserum. Immunohistochemical examination of the nervous tissues revealed distinct staining in the periganglionic tissue of the ganglia, and the perineural sheath of the proximal portion of the peripheral nerves. The neuropil and satellite cells were also stained. In the skin, subcutaneous connective tissues were moderately stained, and the cytoplasm of small mononuclear cells and foamy cells was also stained. The staining patterns were essentially the same in paraffin and cryostat sections. From the findings with sections pretreated with chloroform-methanol (2 : 1, v/v), it was suggested that the periganglionic and perineural stainings were due to glycoproteins, including an SDS-soluble glycoprotein of Mr 280,000, while those of the other regions were due to SGL-II and glycolipids immunologically related to SGL-II. The stainings in the skin sections were largely due to glycoproteins.     

Properties of the raw-starch digesting amylase of Aspergillus sp. K-27: a synergistic action of glucoamylase and alpha-amylase

Glucoamylase and alpha-amylase have been purified from a crude enzyme preparation of Aspergillus sp. K-27. The former was thermostable and seemed to have a "starch-binding site", judging from the results of a kinetic study, and the latter synergistically enhanced the degradation of starch granules with glucoamylase.     

A case of Graves' disease associated with an autonomously functioning thyroid nodule (AFTN) (Marine-Lenhalt syndrome) which spontaneously became a cold nodule

We report a 31-year-old female with Graves' disease associated with an autonomously functioning thyroid nodule (AFTN) (Marine-Lenhalt syndrome) in which the AFTN spontaneously became a cold nodule. Initially the patient was thyrotoxic and had diffuse goiter with an elevated radioiodine uptake. She became euthyroid following six months of antithyroid drug therapy, and in addition to diffuse goiter, the solitary hot nodule was palpable in the left lobe. Fourteen months later, hyperthyroidism recurred and the thyroid scan revealed diffuse radioiodine uptake with a cold area in the nodular region. The resected nodule showed extensive degeneration and the histological diagnosis was follicular adenoma with Graves' disease. We discussed the significance of recognizing the syndrome and also compared the frequency of spontaneous degeneration in AFTN and in solitary cold nodules.