Histochemical localization of adenylate cyclase activity in some mammalian taste papillae

The localization of adenylate cyclase activity in the fungiform,foliate and circumvallate papillae of rats, rabbits, cats anddogs was determined histochemically using an incubation mediumwith a high pH. Light-microscopic study showed that adenylatecyclase activity is localized not only at the apex of tastebuds but also in other tissues, such as the von Ebner's glandsand the blood vessels or capillaries. The adenylate cyclaseactivity at the apex of taste buds was detectable in all thetaste papillae of rats, rabbits, cats and dogs except for thefungiform papillae of rabbits, though the amount of reactionproduct varied in different papillae. Electron-microscopic studyshowed that the number and density, as well as the size, ofsmall round-shaped electron-dense granules caused by the precipitationof lead with imidodiphosphate at the apex of taste buds arelow in the circumvallate papillae of cats compared with thosein the foliate papillae of rabbits. This may explain the resultthat the amount of reaction product varied in different papillae.     

Entrapment of Lavandula vera cells with synthetic resin prepolymers and its application to pigment production

Summary Cultured cells of Lavandula vera were entrapped with photosensitive synthetic resin prepolymers (PVA-SbQ). PVA-SbQ-entrapped cells grew well inside gel matrices and synthesized de novo blue pigments in the presence of l-cysteine as an inducer. The entrapped cells were superior to calcium alginate-entrapped cells judging from cell growth and total pigment productivity. Release of the pigments, which were almost insoluble in water, from the gels was markedly enhanced by the increase in hydrophilicity of the cell-entrapping gels. The entrapped cells could be used repeatedly for the pigment production.Dedicated to Professor Dr. Georg Manecke on occasion of his 70th birthday     

Purification and some properties of carboxylesterase of rat adipose tissue

Carboxyl ester hydrolase was obtained from rat epididymal adipose tissue in an electrophoretically homogeneous form. Purification was achieved by acetone precipitation, followed by successive chromatographies on DEAE-cellulose and hydroxyapatite and then isoelectric focusing. The monomeric molecular weight of the enzyme was 65 000 and the enzyme associated to form trimers. The enzyme had an isoelectric point at pH 5.9 and contained 2.1% carbohydrate moiety per protein with a molecular weight of 65 000. The amino terminal residue of the enzyme was glycine. The enzyme catalyzed the hydrolysis of short chain triacylglycerols such as tributyrin and medium chain monoacylglycerols such as monocaprin, but not the hydrolysis of cholesterol ester. The optimum pH for the enzymatic function of this enzyme for methyl butylate was 8.0. An antibody against the highly purified enzyme preparation induced in rabbits strongly inhibited the esterase of rat adipose tissue, but did not inhibit the esterase of rat liver, intestinal mucosa and serum.     

Metabolism of 3-deoxyglucosone,an intermediate compound in the Maillard reaction,administered orally or intravenously to rats

Tha Amadori rearrangement compound, the product in the early step of the Maillard reaction of proteins with glucose, is known to be degraded into 3-deoxyglucosone (3DG), a 2-oxoaldehyde. In order to elucidate the metabolic pathway of 3DG, [¹⁴C]3DG was synthesized from [¹⁴C]-glucose and administered to rats orally and intravenously. 2 h after oral administration of [¹⁴C]3DG, the percentages of radioactivity (RaI%) in stomach, small intestine and urine were 3.9, 60 and 6.4%, respectively, while RaI% in liver, kidney, spleen, blood and CO₂ were less than 0.5%. The absorption rate of 3DG was obviously lower in comparison with that of glucose. 3 h after intravenous administration of [¹⁴C]3DG, the RaI% in urine was 72% and those in liver, kidney, spleen, blood and CO₂ were less than 1%. It therefore appeared that the absorbed 3DG was not biologically utilized by the rats, but was rapidly excreted in the urine. Some metabolites of [¹⁴C]3DG were detected in urine by TLC-autoradiography. The main metabolite was purified and identified as 3-deoxyfructose by FD-MS and ¹³C-NMR spectroscopy, indicating that the aldehyde group of 3DG was reduced to an alcohol.     

TGF-β1 increases cellular invasion of colorectal neuroendocrine carcinoma cell line through partial epithelial-mesenchymal transition

Epithelial–mesenchymal transition (EMT) plays a pivotal role in cancer progression and metastasis in many types of malignancies, including colorectal cancer. Although the importance of EMT is also considered in colorectal neuroendocrine carcinoma (NEC), its regulatory mechanisms have not been elucidated. We recently established a human colorectal NEC cell line, SS-2. In this study, we aimed to clarify whether these cells were sensitive to transforming growth factor beta 1 (TGF-β1) and whether EMT could be induced through TGF-β1/Smad signaling, with the corresponding NEC cell-specific changes in invasiveness. In SS-2 cells, activation of TGF-β1 signaling, as indicated by phosphorylation of Smad2/3, was dose-dependent, demonstrating that SS-2 cells were responsive to TGF-β1. Analysis of EMT markers showed that mRNA levels changed with TGF-β1 treatment and that E-cadherin, an EMT marker, was expressed in cell-cell junctions even after TGF-β1 treatment. Invasion assays showed that TGF-β1-treated SS-2 cells invaded more rapidly than non-treated cells, and these cells demonstrated increased metalloproteinase activity and cell adhesion. Among integrins involved in cell-to-matrix adhesion, α2-integrin was exclusively upregulated in TGF-β1-treated SS-2 cells, but not in other colon cancer cell lines, and adhesion and invasion were inhibited by an anti-α2-integrin blocking antibody. Our findings suggest that α2-integrin may represent a novel therapeutic target for the metastasis of colorectal NEC cells.     

In Vitro Reconstitution of Anti-Sheep Erythrocyte Antibody Response of T Cell-Depleted Spleen Cells by Allogeneic T Cells or by Factors Derived from Them

Restoration of the impaired antibody response to sheep erythrocytes (SRBC) in cultures of mouse spleen cells, which were deprived of thymus-derived lymphocytes (T cells) by treatment with anti-mouse brain-associated θ (BAθ) antiserum and complement, was studied by adding a small portion of syngeneic or allogeneic normal spleen cells in vitro. Allogeneic spleen cells had a far greater effect than syngeneic spleen cells on the restoration, as far as the normal spleen cells added were able to recognize the alloantigens on the anti-BAθ serum-treated spleen cells (bone marrow-derived lymphocytes). Treatment of the allogeneic spleen cells with mitomycin C did not affect their activity in the restoration of the impaired antibody response. The possibility that the role of T cells in the antibody response to SRBC may be replaced by a nonspecific mediator derived from T cells reacting with allogeneic cells was proven by the finding that supernatant of the mixed allogeneic spleen cell cultures restored the impaired anti-SRBC antibody response of the T cell-depleted spleen cells. The effect of such culture supernatant on the restoration of the antibody response was greatest when it was added to the T cell-depleted spleen cell cultures one day after cultivation with SRBC, suggesting that the effectiveness may result from triggering of the proliferation and differentiation of antibody-forming cell precursors, which have already reacted with the antigen, to antibody-forming cells.     

Enzymatic and chemical inactivation of partially purified prothoracicotropic (brain) hormone of the silkworm,Bombyx mori

The effects of various enzymatic and chemical treatments on the biological activity of the partially purified PTTH are described. PTTH was inactivated by pepsin, trypsin and α-chymotrypsin. Leucine aminopeptidase and carboxypeptidase A did not affect the biological activity of PTTH, suggesting that N- and C-terminus are blocked. Treatments with chemical reagents suggest that the tryptophan residue and disulfide bond are essential for the activity, whereas the sulfhydryl group is not. Tyrosinase exerted no effects. Glycosidases, neuraminidase, and periodate oxidation did not affect the activity, suggesting that carbohydrates are not essential for the biological activity of PTTH.     

Cytochemical Localization of Guanylyl Cyclase Activity in Rabbit Taste Bud Cells

Guanylyl cyclase activity was cytochemically demonstrated inrabbit foliate taste buds. The enzymatic activity was localizedin the apical portion (microvilli and neck) of taste bud cells.Especially strong activity was observed on the microvillousmembrane of type I (dark) cells and often on a blunt processof type III cells. The microvilli of type II (light) cells showedweak enzymatic activity. Considering that the apical portionof taste cells is a likely site of interaction between tastestimuli and the cells, the results support the idea that cyclicGMP is involved in taste transduction.