Relationship between brain trehalase activity and trehalosema during direct and diapausing development in Pieris brassicae

• 1.1. Brain trehalase specific activity and trehalosemia were measured during the end of the developmental life cycle in non-diapausing and diapausing insects.
• 2.2. During non-diapausing development, trehalosemia reached maximum values at the beginning of pupal life. Then a constant decrease was observed up to the end of adult life.
• 3.3. The specific activity of brain trehalase was maximum when the insects were in active feeding periods, minimum activity appearing during moulting phases.
• 4.4. During diapausing development, trehalosemia was very high at the beginning of pupal life, particularly when insects were exposed to wintering conditions.
• 5.5. When diapause was broken, trehalosemia fell, announcing adult emergence.
• 6.6. Brain trehalase activity showed the same qualitative variations as in non-diapausing larvae, but with rather lower values.
• 7.7. During pupal life, brain trehalase activity decreased markedly during the long period necessary to obtain diapause breakdown.
• 8.8. Wintering conditions allow a progressive increase of brain trehalase activity, which preceded the fall of trehalosemia.

     

Trehalose synthase and trehalase behaviour in yeast cells in anhydrobiosis and hydrobiosis

• 1.I. Trehalose synthase and trehalase behaviour has been analysed in cultured yeast cells isolated from baker's yeast to increase the understanding of the mechanisms involved in trehalose content modifications observed in anyhydrobiois and hydrobiosis.
• 2.2. After desiccating yeast cells to a constant weight, trehalose levels sharply increased, whereas the glycogen content decreased, trehalose synthase was stimulated and trehalase was significantly inhibited.
• 3.3. In desiccated cells after a rehydration for 15 min, trehalose levels dropped, the glycogen content further decreased, the activity of trehalose synthase declined while that of trehalase was dramatically stimulated.
• 4.4. After rehydration for 12hr, while the trehalose and glycogen content decreased even more, the behaviour of the two enzymes was completely reversed, trehalose synthase being activated and trehalase inhibited.
• 5.5. The reasons for such impressive enzyme activity alterations in desiccated and rehydrated cells for the moment remain unknown.

     

The effect of cortisol on stimulation of enzymatic activity and absorption of amino acids in the small intestine of adult hamsters

• 1.1. The s.c. administration of cortisol to hamsters (50 mg/kg body wt/day for 4 days) produces a significant increase in maltase sucrase, alkaline phosphatase and leucineaminopeptidase activity in intestinal mucosa.
• 2.2. Lactase activity is unaffected by cortisol.
• 3.3. Gamma-glutamyltranspeptidase activity increases slightly in females but remains unchanged in males.
• 4.4. Cortisol causes increase in proline and glycine absorption without changing the absorption of lysine.

     

Is the orcadian clock of gonyaulax held stationary after a strong pulse of anisomycin?

• 1.1. Gonyaulax polyedra cells were treated with two sequential pulses of a protein synthesis inhibitor (anisomycin) in order to analyse a possible stopping of the circadian clock by the first pulse.
• 2.2. Inhibition of protein synthesis during these pulses and after centrifugation and resuspension of the cells was determined by measuring the incorporation of labelled amino acids.
• 3.3. The effects of the second pulses on the clock were measured as phase shifts of the glow rhythm with respect to a control rhythm that had been subjected to the initial pulse only.
• 4.4. From the observed phase shifts of the second pulses we conclude that the clock is not stopped by the first pulse but is immediately shifted to a different phase.

     

Induction kinetics of immune antibacterial proteins in pupae of Galleria mellonella and Pieris brassicae

• 1.1. Pupae of Galleria mellonella and Pieris brassicae given an injection with live, non-pathogenic Enterobacter cloacae or abiotic foreign molecules induce an acquired immunity that corresponds with the synthesis of haemolymph proteins of antibacterial activity.
• 2.2. This humoral defensive response which persists for several days, differs quantitatively between insect species and between the inducers used, although very different foreign bodies induced the same immune proteins in both lepidopteran insects.
• 3.3. A stronger and longer lasting response was consistently noticed in pupae immunized with non-pathogenic bacterium than after sterile nutrient broth injections.
• 4.4. A demonstrably elevated activity of haemolymph lysozyme and trace activity of cecropins found in pupae of Galleria treated with saline W, a salt solution physiological to moths, disappear soon after 36 hr from injection.
• 5.5. In P. brassicae, however, sterile insect Ringer can give a varying, if present at all, immune response.
• 6.6. A mechanical injury (sterile wounding of insect body) can occasionally induce a similar but much weaker response.
• 7.7. The antibacterial activity was drastically reduced in Pieris or completely depressed in most pupae of Galleria when actinomycin D or cycloheximide was given at an early time post-immunization with E. cloacae.
• 8.8. It is concluded that the de novo synthesis of ribonucleic acid and immune proteins is required for expression of antibacterial activity in pupal haemolymphs.
• 9.9. The synthesis of an immune mRNA was completed about 7 hr after the injection of the immunizing bacteria.

     

The influence of calcium and magnesium on sea bass (Dicentrarchus labrax) intestinal brush border membrane purification and activity

• 1.1. The activity of brush border enzymes (alkaline phosphatase, maltase, sucrase, trehalase, leucine amino peptidase) was higher in purified membranes prepared with calcium. The contamination of these membranes with basolateral membranes was also lower (1.27 for Na-K-ATPase activity ratio).
• 2.2. The extraction of brush border lipids was carried out according to Folch adapted method. Two dimensional thin layer chromatography was used to separate the phospholipidic fractions. Fatty acids of phospholipids were analysed using gas chromatography after acid transmethylation (column SP 2330).
• 3.3. Phospholipids are composed of phosphatidylcholine (PC: 33%), phosphatidylethanolamine (PE: 30%), sphingomyeline (SM: 21%), phosphatidylserine (PS: 14%) and phosphatidylinositol (PI: 2%). 4. PC, PE and PS are characterized by high levels of unsaturated fatty acids (monounsaturated MUFA: 21.5% and polyunsaturated PUFA: 34.9%). The most abundant PUFA belong to the (n-3) family [18:3 (n-3), 20:5 (n-3) and 22:6 (n-3)].
• 4.5. Fatty acids from sphingomyelin of purified membranes have low proportions of PUFA (13.5%) but higher proportions of MUFA (39.5%).
• 5.6. No specific differences were found between calcium and magnesium prepared membranes.
• 6.7. The low content in LPC and the absence of LPE confirmed the absence of major structural lipids transformation during the membrane purification with calcium or magnesium.
• 7.8. Glycine transport was measured during 10 sec at different temperatures using the rapid filtration technique. Glycine transport was higher with Na⁺ than with K⁺. In the presence of Na⁺, this transport increases with temperature.
• 8.9. Arrhenius curves were mono phasic without obvious breakpoint and indicated no phase transition in the lipid bilayer.
• 9.10. A significant Na⁺ dependent glycine transport has been characterized at low temperatures (0°C) which suggests a possible role of membrane polyunsaturated fatty acids in the control of glycine transport.

     

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.

     

The activities of ribosome-degrading enzymes and of a proteinase inhibitor in Tetrahymena pyriformis during starvation

• 1.1. In starved Tetrahymena acid RNase decreased but acid proteinase and a heat-stable proteinase inhibitor both increased.
• 2.2. A greater proportion of proteinase than RNase was released from the lysosomes of growing cells by homogenization, but progressively less proteinase was released during starvation.
• 3.3. Inhibitors of protein synthesis enhanced the decrease in RNase and prevented the increase in proteinase and proteinase inhibitor. Chloroquine caused a large increase in both enzymes.
• 4.4. Proteinase and RNase may be located in different lysosomes which together participate in ribosome destruction, but this process is unlikely to be limited by the total amount of these lysosomal hydrolases.

     

Action of free radical generating systems upon the biological and immunological properties of caeruloplasmin

• 1.1. Exposure of human caeruloplasmin, an acute phase protein with antioxidant properties, to a mixture of xanthine/hypoxanthine and xanthine oxidase as a source of reactive oxygen intermediates decreased its ferroxidase and ascorbate oxidase activities and its ability to inhibit lipid peroxidation.
• 2.2. Immunological reactivity was also altered.
• 3.3. Exposure to hydrogen peroxide mimicked these effects.
• 4.4. Exposure to low-intensity u.v. irradiation depressed caeruloplasmin's ability to inhibit iron-catalysed hyaluronic acid degradation.
• 5.5. The results may explain the mechanism of the observed inactivation of caeruloplasmin within human rheumatoid synovial fluid.

     

Seasonal changes of water,electrolytes and aldosterone levels in blood serum,brain and kidney of the Egyptian cobra “Naja haje haje”

 

• 1.The levels of water, Na, K, Ca and Mg in blood serum, brain and kidney and aldosterone level in blood of Naja haje haje were studied during the different phases of the annual cycle.
• 2.The water content in the tissues studied displayed only minor changes as the animals passed from one phase to the other.
• 3.A significant increase in Na was recorded in the brain during the different phases indicating a depressed sodium pump, whereas the blood Na level showed a significant decrease during hibernation.
• 4.K increased in blood serum, brain and kidney during hibernation, while a nonsignificant decrease was found in blood serum during arousal. The brain may act as a potassium reservoir.
• 5.An increase in Ca and Mg concentration was recorded in blood serum, brain and kidney during prehibernation and hibernation. The data suggested a homeostatic function in the transport and metabolism of these cations.
• 6.Aldosterone exhibited a highly significant decrease especially during hibernation. The aldosterone regulation of ionic composition is discussed.
• 7.Na/K and Ca/Mg ratios in the brain may explain the decreased excitability during winter torpor.

     

Properties of enzymes hydrating epoxides in human epidermis and liver

• 1.1. Cytosolic and microsomal epoxide hydrolyzing enzymes of human skin and liver were compared and found to be different.
• 2.2. Epidermal and hepatic cytosolic epoxide hydrolases were different in terms of substrate selectivity, pI, inhibitor sensitivity and affinity Chromatographic properties.
• 3.3. Microsomal epoxide hydrolases had the same pIs but different substrate selectivities.
• 4.4. Cytosolic epoxide hydrolase from adults had higher specific activity than that from neonates or cultured epidermis, but lower activity than adult hepatic enzymes.
• 5.5. The sizes of cytosolic epoxide hydrolase from epidermis and liver were similar and lower than that from cultured fibroblasts.
• 6.6. Cytosolic epoxide hydrolase from all sources shared similar antigenic determinants.

     

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.

     

Phosphatidylethanolamine: Ceramide-ethanolaminephosphotransferase activity in synaptic plasma membrane vesicles. Influence of some cations and phospholipid environment on transferase activity. Further proof of its location

• 1.1. Synaptic plasma membrane vesicles (SPMV) from rat brain synthesized ceramide-phosphoethanolamine (SpE), an analogue of sphingomyelin (SpC) from phosphatidylethanolamine (PE) and ceramide.
• 2.2. This reaction was catalyzed by PE: ceramide-phosphotransferase.
• 3.3. The presence of PC did not modify the SpE synthesis and PI and PS at twice PE concentration seemed to be activators; only PG was an inhibitor at all concentrations.
• 4.4. Some cations (Mg²⁺, Mn²⁺) were without effect, while Ca²⁺ increased transferase activity, so was interesting to study.
• 5.5. Transferase was compared with sialidase (external enzyme).
• 6.6. Kinetics other than those already performed by us were undertaken in order to confirm its location.

     

Main serum protein of rainbow trout (Salmo gairdnerii): its biological properties and significance

• 1.1. Main serum α₁-protein (α₁P) of rainbow trout was purified and its biochemical and physico-pathological properties were studied.
• 2.2. α₁P was suggested to be a primitive protein having both properties of albumin and AFP in serum proteins of mammals according to the following results.
• 3.3. Molecular weight (75,000), two kinds of molecules (pI 4.55 and 5.05) and amino acid composition.
• 4.4. Dye- or ConA binding activity.
• 5.5. Estrogen binding activity and inhibitory effect on lymphoblastoid-forming activity.
• 6.6. Possible osmotic regulator.
• 7.7. Significant elevation of blood α₁P level in the course of hepatoma induction.

     

A novel inhibitor of glycogen phosphorylase from crayfish hepatopancreas

• 1.1. A novel glycogen phosphorylase inhibitor was partially purified from crayfish hepatopancreas.
• 2.2. The inhibitor was found only in two species of crayfish examined, and not in lobster, fresh and salt water clams, mussels or cockroaches.
• 3.3. The inhibitor is a small protein (M_r = 23,000) which did not show proteolytic activity.
• 4.4. Preliminary kinetic analysis of the inhibitory mechanism indicated that it bound to both glycogen and the glycogen phosphorylase protein.
• 5.5. Inhibitor binding to glycogen resulted in a competitive inhibition pattern with respect to glycogen phosphorylase (inhibition constant of ca 10 μg/ml).
• 6.6. The inhibitor also bound glycogen phosphorylase directly with a binding coefficient of 100 μg/ml resulting in a partially non-competitive inhibition pattern with respect to phosphate.

     

Identification of a glycoprotein complex containing a glycogen synthase isozyme in Ascaris Suum obliquely-striated muscle

• 1.1. A glycogen/protein complex which contains the major portion of glycogen synthase activity in Ascaris suum muscle has been purified.
• 2.2. The complex contains two proteins which can be dissociated from a glycoprotein component.
• 3.3. The glycoprotein contains glycogen-like domains and is resistant to trypsin digestion.
• 4.4. The glycogen synthase activity in the purified complex catalyzes glycogen synthesis in the absence of exogenous glycogen, but demonstrates an absolute glucose 6-phosphate requirement for activity.
• 5.5. The data support the hypothesis that this isozyme of glycogen synthase is significantly different from the cyclic AMP-regulated enzyme.

     

Effects of ATP and cAMP on salt and sugar (responses of chemosensilla in the blowfly)

• 1.1. The addition of cAMP to stimulating solutions of NaCl, fructose (furanose sugar), sucrose, or glucose (pyranose sugars) decreases the responsiveness of labellar chemosensilla in Phormia.
• 2.2. The addition of ATP, while decreasing the responsiveness to NaCl or fructose enhances the responsiveness to glucose and sucrose.
• 3.3. The inhibiting effect of ATP on NaCl or fructose responses is suppressed by GDPßS, an inhibitor of adenylate cyclase (and thus of cAMP synthesis); moreover GDPßS further enhances the increase in response due to ATP when added to the sucrose or glucose solutions.
• 4.4. Results suggest a possible involvement of cAMP and ATP in the taste reception mechanism in the blowfly.

     

Spatial Distribution of Endogenous Tissue Protease Activity in Gastric Carcinoma Mapped by MALDI Mass Spectrometry Imaging

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Highlights

• •New MALDI MS imaging sample preparation workflow reveals tissue protease activity.
• •Differential time- and inhibitor concentration-dependence confirm active proteases.
• •Mouse gastric tumor displays high protease activity compared to surrounding tissue.
• •Proteomic data and biochemical protease activity assay support MALDI MSI results.

     

Regulation of spermidine transport in l1210 cells

• 1.1. 1 mM 2-amino isobutyric add (AIB), glutamine or asparagine when preincubated for 3 hr with L1210 cells promoted a marked increase in the rate of spermidine uptake.
• 2.2. Cycloheximide also increased the transport rate and completely prevented the increase due to AIB.
• 3.3. Trifluoperazine and iso-H7 inhibited the uptake of spermidine, much less the uptake of AIB.
• 4.4. Adenosine promoted an increase in the uptake of AIB, a decrease in that of spermidine.
• 5.5. Hypotonic stress also increased the rate of spermidine transport. This modification was only partially prevented by cycloheximide.
• 6.6. Okadaic arid had no effect on this increase, whereas it prevented the increase of ODC activity.

     

Purification and characterization of elastase from the pyloric caeca of rainbow trout (Oncorhynchus mykiss)

• 1.1. An elastase-like enzyme was purified from the pyloric caeca of rainbow trout by hydrophobic interaction, cation exchange and gel-filtration chromatography.
• 2.2. The approximate molecular weight of the elastase was 27 kDa and the isoelectric point was remarkably basic.
• 3.3. The pH optimum of this enzyme was 8.0, when assayed with Succinyl-Ala-Ala-Ala-p-Nitroanilide.
• 4.4. When assayed with Succinyl-Ala-Ala-Ala-p-Nitroanilide, the enzyme activity had a temperature optimum of 45°C, and the enzyme was stable up to this temperature.
• 5.5. The trout elastase exhibited a higher specific activity than porcine elastase against Succinyl-Ala-Ala-Ala-p-Nitroanilide and elastin-orcein.
• 6.6. The trout elastase was inhibited by elastatinal, PMSF, TPCK, SBTI and Bowman-Birk inhibitor.