Prostaglandin E2/parathyroid hormone-induced suppression of alkaline phosphatase activity is mediated by protein kinase C

• 1.1. Bone resorptive factors, prostaglandin E2 and parathyroid hormone are shown to suppress alkaline phosphatase activity in a rat osteoblastic cell line.
• 2.2. Phorbol myristate acetate, but not dibutyryl cAMP or calcium ionophore can suppress alkaline phosphatase activity.
• 3.3. The protein kinase C inhibitors (H89, staurosporine) are able to block the suppression of alkaline phosphatase activity induced by prostaglandin E2 and parathyroid hormone.
• 4.4. These data suggest that protein kinase C is involved in the inhibition of alkaline phosphatase activity induced by prostaglandin E2 and parathyroid hormone.

     

Metabolic,Anti-apoptotic and Immune Evasion Strategies of Primary Human Myeloma Cells Indicate Adaptations to Hypoxia*

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Highlights

• •In-depth proteome profiling of primary human myeloma cells
• •Characteristics of myeloma cells are related to hypoxic bone marrow conditions
• •Myeloma cells show specific immune evasion strategies
• •Metabolic adaptations involve tumor and stroma cells

     

Osmotically-induced volume changes in isolated cells of a pond snail

• 1.1. To assess whether the stretch-activated (SA) channels in snail cells could contribute to osmoregulation, information is needed about the behaviour of the cells under anisosmotic conditions.
• 2.2. Cells of Lymnaea stagnalis were therefore examined during acute hyposmotic stress (HOS).
• 3.3. Kidney, heart and neuronal cells (monitored photographically) swelled less than expected for strictly semipermeable cells, but exhibited no regulatory volume decrease.
• 4.4. Long-term viability of the cells was not compromised following acute hyposmotic stress.
• 5.5. Quinidine, which blocks SA channels in Lymnaea, intensified stress-induced swelling most markedly in kidney cells.
• 6.6. The data can, however, be explained without invoking recruitment of SA channels.

     

Changes in the activities of lysosomal enzymes in the fat body and midgut of two lepidopteran insects (Mamestra brassicae and Pieris brassicae) during metamorphosis

• 1.1. The activities of three lysosomal enzymes (acid phosphatase, β-galactosidase, catepsin D) was observed during metamorphosis in the fat body and midgut cells of two insects (Mamestra brassicae and Pieris brassicae).
• 2.2. The activities increased slightly during the feeding period and showed a sharp rise at the beginning of the wandering period.
• 3.3. Subsequently, a decrease was observed during the pre-pupal stage and pupation.
• 4.4. The activities increased again 2 days after the larval-pupal moult.
• 5.5. We suggest that an inhibitory mechanism works in the studied cells before pupation to protect the stored proteins from the degradation until the beginning of differentiation of imaginai cells in the pupal stage.

     

An in vitro study of short-chain fatty acid concentrations,production and absorption in pig (Sus scrofa) colon

• 1.1. Short-chain fatty acid concentration was 180mmol/l in the proximal colon and decreased to 108 mmol/l in the rectum.
• 2.2. Fermentation in chymus from different regions of the colon, showed the pattern of end products to reflect the substrate and not the site of the colon.
• 3.3. Isolated mucosa from proximal and distal colon had electroneutral sodium absorption of 4.8 ± 0.2 and 2.9 ± 0.8 μeq/cm² hr in bicarbonate free media, which was abolished in the absence of chloride.
• 4.4. Electroneutral sodium absorption was enhanced by short-chain fatty acids in the proximal colon and could be described by Michaelis-Menten kinetics with K_m 2.0–11 mmol/l and J_m 1.6–3.6μeq/cm² hr. In the distal colon the stimulation was smaller and propionate even inhibited sodium absorption.
• 5.5. Butyrate was absorbed in the proximal colon, whereas acetate and propionate, and butyrate in the distal colon had a flux ratio of one.
• 6.6. Amiloride (5 mmol/l) inhibited sodium absorption and net butyrate absorption.

     

Correlation of acid phosphatase but not alkaline phosphatase activity with myelination in the developing mouse brain

• 1.1. Neonatal mice received subcutaneous injections of buffer, thiourea (TU) or propylthiouracil (PTU).
• 2.2. The PTU-treated mice were sacrificed on postnatal day 14 (P14) and the TU-treated mice on P28.
• 3.3. Brain weights of the TU- and PTU-treated mice were not significantly different from the controls.
• 4.4. Acid but not alkaline phosphatase activity in the braistem decreased after TU and PTU treatment.
• 5.5. Myelination as indicated by intensity of luxol fast blue staining was weaker in drug-treated animals.
• 6.6. The level of myelin marker enzyme, 2′,3′-cyclic nucleotide 3′-phosphohydrolase, was lower in the brainstem of PTU-treated animals.
• 7.7. The results suggest a correlation between acid phosphatase but not alkaline phosphatase activity with myelination in the developing mouse brain.

     

Effects of membrane-perturbing drugs and noradrenalin on cAMP accumulation and red cell water content in carp (Cyprinus carpio) red cells

• 1.1. Carp red cells were treated with drugs that affect the cell membranes. The water content of the cells and the accumulation of cAMP in the cells were measured in normoxia and in hypoxia using non-stimulated and adrenergically stimulated cells.
• 2.2. WGA, DIDS + CCCP and A23187 increased the water content of nonstimulated normoxic cells.
• 3.3. In hypoxia ouabain and DIDS + CCCP increased the water content but cytochalasin B, NPM, DIDS, CCCP and A23187 + CA²⁺ abolished the hypoxia-induced swelling.
• 4.4. Any membrane perturbation induced some cAMP formation, Sophora and Anquilla lectins being most potent.
• 5.5. Also in adrenergically stimulated cells, membrane perturbation generally increased cAMP formation.
• 6.6. However, cAMP accumulation diminished in cells treated with cytochalasin B, CCCP and DIDS + CCCP.
• 7.7. The adrenergic swelling of carp red cells was reduced in normoxia by DIDS. NPM and CCCP increased the adrenergic swelling in normoxia to hypoxic level.
• 8.8. In hypoxia WGA and Anquilla lectin decreased the swelling.

     

Some properties of ATPase activity in the intact cells of yeast Saccharomycopsis fibuligera

• 1.1. The properties of ATPase activity were studied with the cells at the early stationary phase of Saccharomycopsis fibuligera.
• 2.2. Optimal pH for the activity was approximately 7.
• 3.3. The activity was stimulated by Mg²⁺.
• 4.4. The activity was inhibited by NaF, DCCD, oligomycin, NaN₃, NaVO₃, or PCMB but not inhibited by ouabain.

     

Clastogenic effects of five carcinogenicmutagenic chemicals on the cells of the common carp,cyprinus carpio L.

• 1.1. The cytogenetic effects of various i.p. treatments with five carcinogenic-mutagenic chemicals and three doses for each (aflatoxin Bl, Aroclor 1254, benzidine, benzo[a]pyrene and 20-methylcholanthrene), were investigated in the cells of the common carp, Cyprinus carpio.
• 2.2. Injection with distilled water and corn oil served as the two control groups.
• 3.3. For detecting cytogenetic damage we used two test systems, chromosomal aberrations (CA) in kidney cells and micronucleated erythrocytes (M).
• 4.4. At 48 hr after treatment with the chemicals under investigation, the frequencies of CA and M were clearly increased in a dose-response manner compared to the control groups.

     

Effect of inorganic phosphate on synthesis of 5-phosphoribosyl-1-pyrophosphate in cultured plant cells

• 1.1. Inorganic phosphate (Pi) was absorbed rapidly by suspension-cultured cells of Catharanthus roseus which had previously been cultured in Pi-free Murashige Skoog medium.
• 2.2. The intracellular levels of ATP, ADP and 5-phosphoribosyl-l-pyrophosphate (PRPP) increased markedly during the 24 hr which followed the addition of Pi (1.25mM).
• 3.3. Availability of PRPP in vivo, estimated by the measurement of nucleotide synthesis from [8-¹⁴C]adenine, was also increased by addition of Pi.
• 4.4. Only a 20% increase in the maximum catalytic activity of PRPP synthetase was observed in extracts of cells, prepared 24 hr after addition of Pi.
• 5.5. In contrast to results for mammalian PRPP synthetase, the activity of PRPP synthetase, partially purified from Catharanthus roseus, was inhibited by concentration of Pi greater than 5mM.
• 6.6. The mechanisms involved in the increased availability of PRPP and the synthesis of adenine nucleotides in the plant cells cultured in Pi-containing medium are discussed.

     

Purification of glycosylphosphatidylinositol-anchoring aminopeptidase in from the plasma membrane of larval midgut epithelial cells of the silkworm,Bombyx mori

• 1.1. Aminopeptidase N was selectively released from larval midgut of silkworm, Bombyx mori, by phosphatidylinositol-specific phospholipase C, and purified to a homogeneous state by ion exchange, gel filtration. Con A-Sepharose and 4-aminobenzyl phosphonic acid-agarose column chromatographies.
• 2.2. The purified aminopeptidase N preparation showed 190.8 U/mg of specific activity. Its molecular weight was estimated to be around 100 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
• 3.3. Purified aminopeptidase N molecule preferentially hydrolyzed Leu-, Ala- and Met-p-nitroanilide as substrates. Especially, Leu-p-nitroanilide proved to be the best substrate for aminopeptidase N from larval midgut of silkworm.
• 4.4. By treatment with phosphatidylinositol-specific phospholipase C, two other hydrolases, alkaline phosphatase and alkaline phosphodiesterase I, were also solubilized from silkworm midgut.

     

Distribution of serine esterase activity in the lymphoid system of C57bl/6 mice,effect of aging on the enzymatic activity

• 1.1. The activity of serine esterase (SE) was investigated in the lymphoid system of C57BL/6 mice. SE activity increased in the lymphoid tissues with their content of mature T-lymphocytes, except that high levels were also observed in various populations of bone marrow cells.
• 2.2. The maturation of T-lymphocytes in the thymus was accompanied by an increase in their SE activity.
• 3.3. Experiments on the influence of age on SE activity showed that while thymocytes were not affected, a three-fold increase in activity occurs in spleen lymphocytes between the ages of 26 and 78 wk.

     

A quantitative method for analysis of radiolabelled proteoglycans synthesized by cultured human arterial smooth muscle cells

• 1.1. Sulphate labelled proteoglycans (PG) synthesized by cultured human arterial smooth muscle cell have been quantified using an improved method based on a combination of specific enzymes and ethanol precipitation.
• 2.2. The present method gives quantitative data of PGs and subclasses allowing batchwise analysis of a large number of samples.
• 3.3. Approximately 81 % ± 1.7% (mean ± SD, n = 6) of total PGs synthesized by human arterial smooth muscle cells accumulated in medium.
• 4.4. In cell layer and medium chondroitin sulphate proteoglycan constituted 65.0% ± 0.3% and 75.8% ± 0.7% (mean ± SD, n = 3), respectively of sulphated PGs.
• 5.5. Heparan sulphate proteoglycan accounted for 26.8% ± 0.6% in cell layer and 22.6% ± 0.5% (mean ± SD, n = 3) in medium of sulphated PGs.

     

Haematology of the australian eastern quoll,Dasyurus viverrinus

• 1.1. A variety of haematological parameters were determined in adult Dasyurus viverrinus.
• 2.2. Haemoglobin and red cell counts were high with a very low mean cell volume.
• 3.3. Basophils are absent but the eosinophils contain small numbers of basophilic granules which may indicate a dual role for this cell.
• 4.4. “Ring Form” leucocytes are present.
• 5.5. Three types of red cell picture could be identified, some animals showing large numbers of spherocytes, spicule cells, and inclusion bodies.
• 6.6. These cells resemble those found in some inherited human haemolytic anaemias but there was no evidence of haemolysis in the animals.
• 7.7. An alkali resistant haemoglobin component is present.

     

Purification and some properties of an atypical alkaline p-nitrophenylphosphate phosphatase activity from Halobacterium halobium

• 1.1. An alkaline p-nitrophenylphosphate phosphatase has been purified 440-fold from extracts of Hatobacterium halobium.
• 2.2. The enzyme has an apparent molecular weight of 24,000.
• 3.3. A K_m value for p-nitrophenylphosphate of 1.12mM has been found under optimal conditions.
• 4.4. The enzyme is selectively activated and stabilized by Mn²⁺.
• 5.5. It requires high salt concentrations for stability and maximum activity.
• 6.6. It displays an unusual restricted substrate specificity of 25 phosphate esters tested, only phosphotyrosine and casein were hydrolysed besides p-nitrophenylphosphate.

     

Characterization of a blue astaxanthin protein from the carapace of the crayfish Astacus leptodactylus

• 1.1. A blue carotenoprotein (λ_max = 634 nm) containing astaxanthin as prosthetic group, was extracted and purified from the carapace of the crayfish Astacus leptodactylus.
• 2.2. The blue carotenoprotein contained (3S,3′S)-astaxanthin, (3R,3′S, meso)-astaxanthin and (3R,3′R)-astaxanthin in relative ratio 38:41:21.
• 3.3. The blue carotenoprotein had an approximate mol. wt of 440,000 (gel filtration) and 437,000 (gradient gel electrophoresis).
• 4.4. Sodium dodecyl sulphate polyacrylamide gel electrophoresis indicated the presence of two polypeptides of 19,600 and 18,600 daltons, with different mobility in polyacrylamide gel electrophoresis in the presence of 6 M urea.
• 5.5. At low ionic strength and in the presence of denaturing agents such as SDS, urea, extreme pH and heat, the blue complex showed a greater stability than most of the carotenoproteins studied to date.

     

Comparison of the proliferation and differentiation of myogenic satellite cells and embryonic myoblasts derived from the turkey

• 1.1. Embryonic and posthatch turkey skeletal muscle development was compared in in vitro studies using clonal-derived embryonic myoblasts and satellite cells.
• 2.2. Although population doubling times were similar between the two lines (25.4 hr for satellite cells and 26.4 hr for embryonic myoblasts), embryonic myoblasts consistently began log phase growth 24 hr earlier than satellite cells.
• 3.3. Differentiation (fusion) of embryonic myoblasts was maximized by 36 hr in Dulbecco's Modified Eagle's Medium containing 1% horse serum compared with 72 hr for satellite cells.
• 4.4. When administered a serum-free medium which supports proliferation of turkey satellite cells, embryonic myoblasts differentiated to form myotubes.

     

Volatile fatty acid excretion during anaerobiosis in the lugworm Arenicola marina

• 1.1. Accumulation and excretion of propionate and acetate during experimental anaerobiosis were investigated in the lugworm Arenicola marina.
• 2.2. The rate of accumulation and the ratio propionate/acetate were found to be tissue-specific.
• 3.3. The excretion of the volatile fatty acids showed a characteristic time course.
• 4.4. The results of experiments analyzing the role of different organs indicate that the excretion of these metabolites proceeded via the undifferentiated surface of the body.
• 5.5. The rate of excretion depended on the concentration gradient between animal and the ambient water, the chain-length of the fatty acid and the pH of the water. Propionate excretion was inhibited by butyrate.

     

Impact of histamine treatment and feeding on the hydrolytic enzyme level of Tetrahymena in culture and in conditions of starvation

• 1.1. The unicellular Tetrahymena pyriformis contains and also produces hydrolytic enzymes, such as glucosidase, phosphatase and glucosaminidase.
• 2.2. Return of Tetrahymena to plain medium after treatment with bacteria alone, histamine alone or bacteria plus histamine was equally followed by persistence of the hydrolytic enzyme activity around the control value and an activity increase at about 60 min.
• 3.3. Incubation of Tetrahymena in salt (Losina-Losinsky) solution after the applied treatment accounted for reduction to practically zero of the glucosidase and glucosaminidase activities, whereas the phosphatase activity tended to increase rather than to decrease in both the bacterium-treated and histamine-treated cultures.
• 4.4. The enzyme activity patterns of the Tetrahymena cells pretreated (imprinted) with histamine did not differ from the control pattern either after re-exposure to histamine or after feeding with bacteria, but showed a uniformization of the activity pattern and a considerable decrease in enzyme activity on incubation (starvation) in salt (Losina-Losinsky) solution.

     

Comparison of U-small nuclear RNA levels in tissues of the silkmoth,Bombyx mori

• 1.1. Tissue-specific abundance of the capped small RNAs in the silkmoth Bombyx mori was compared using preparative immunoprecipitation with anti-trimethylguanosine antibody.
• 2.2. The yields of total capped small RNAs from larval posterior silk gland, 1. early, 2. late in the fifth-instar, and 3. immortal ovarian-derived cells in culture, were determined to be 187, 50 and 218 ng, respectively, per mg of total cellular RNA.
• 3.3. Separation of immunoprecipitated RNAs by polycrylamide gel electrophoresis, followed by densitometric analysis of the bands, allowed the quantitation of individual capped molecules.
• 4.4. This analysis revealed tissue-specific patterns.
• 5.5.|The data indicate that the total abundance of capped small RNAs in Bombyx is highest in rapidly-dividing cells.