Effect of berenil on polyamine metabolism in primary cultured rat hepatocytes

• 1.1. Putrescine and spermidine content increased in hepatocytes during culture. In the presence of 10 μM Berenil, putrescine content was further increased, while the increase of spermidine was prevented.
• 2.2. Ornithine decarboxylase activity was markedly reduced, and to a lesser extent also S-adenosyl-methionine decarboxylase activity.
• 3.3. Berenil appears to promote an increase in the transformation of spermidine into putrescine, and to inhibit the polyamine efflux.

     

Effect of temperature and diet on polyamine concentrations of the European sea bass (Dicentrarchus labrax L.)

• 1.1. A fall of environmental temperature causes a decrease in total polyamine concentrations of heart, red and white muscles of sea bass fed on a diet containing 70% herring meal (diet S).
• 2.2. When sea bass was fed with a diet partially replaced by casein (diet A), an increase of total polyamine concentration in liver and heart was observed at a lower temperature.
• 3.3. In all tissues studied an increase of putrescine concentrations and a parallel decrease of spermidine and spermidine levels were found for both groups S and A of sea bass when the temperature was lowered.
• 4.4. In general concentrations of putrescine, spermidine and spermine were considerably higher in group A when the temperature was lowered.

     

Kinetic study of the inhibition of rat liver ornithine decarboxylase by diamines; considerations on the mechanism of interaction between enzyme and inhibitor

• 1.1. Partially purified rat liver ornithine decarboxylase is inhibited by several diamines including putrescine, 1,3-diaminopropane, cadaverine and p-phenylenediamine.
• 2.2. The inhibition is dependent on pH, being strong at pH above 8 and negligible below pH 6.5.
• 3.3. The kinetic study of the inhibition showed that while the aromatic diamine behaved as a simple competitive inhibitor, the aliphatic diamines presented a more complex pattern of inhibition in which two molecules of inhibitor might bind to the enzyme active site.
• 4.4. The K_I values for the different inhibitors were calculated and the degree of affinity for the enzyme was p-phenylenediamine > putrescine > cadaverine > 1,3-diaminopropane.
• 5.5. A molecular mechanism explaining how one or two molecules of inhibitor can bind to the enzyme is proposed.

     

Epidermal polyamine levels related to cell cycle events during the metamorphosis of Tenebrio molitor L. (insecta,coleoptera): Effect of juvenoid application

• 1.1. Three polyamines were separated by reverse-phase HPLC and detected by fluorescence in Tenebrio epidermis: putrescine, spermidine and spermine.
• 2.2. The levels of these compounds varied during metamorphosis: one peak was observed during the G₂-arrest preceding the pupal-adult mitotic crisis and a second occurred when cells were again G₂-arrested after the mitotic period.
• 3.3. A juvenile hormone analogue, which inhibits the G₂-M transition preparing cells to the adult mitoses, was unable to prevent the first polyamine increase suggesting that juvenile hormone does not act on further development via inhibition of polyamine synthesis.

     

Involvement of polyamines in epidermal growth factor (EGF), transforming growth factor (TGF)-α and -β1 action on culture of L6 and fetal bovine myoblasts

• 1.1. α-Difluoromethylornithine, an irreversible inhibitor of ornithine decarboxylase significantly abolished stimulation of protein synthesis evoked by EGF, TGF-α or -β 1 in L6 and fetal bovine myoblasts.
• 2.2. The participation of polyamines in early events evoked by growth factors was shown by a significant stimulation of ornithine decarboxylase and Sdenosylmethionine decarboxylase activity as well as increased concentration of spermidine and spermine in L6 cells exposed to TGF-α and EGF.
• 3.3. TGF-β 1 at a high concentration (1 ng/ml) increased protein synthesis in L6 myoblasts but inhibited it in fetal bovine myoblasts. Metabolic effects of TGF-β 1 in L6 cells was associated with an enhancement of decarboxylase activities, however there were no significant changes in cellular polyamine concentrations. Presented data suggest that polyamines are involved in the signal transduction pathway of EGF, TGF-α, and -β 1 in L6 and fetal bovine myoblasts.

     

Arginase,ornithine decarboxylase and S-adenosylmethionine decarboxylase in chicken brain and retina

• 1.1. Arginase, ornithine decarboxylase and S-adenosylmethionine decarboxylase are active in both retina and brain. Activity is higher in cerebellum than in the cerebral hemispheres and optical lobes.
• 2.2. Arginase and ornithine decarboxylase are very active in the retina of very young chicks, while S-adenosylmethionine decarboxylase is poorly active. By contrast, S-adenosylmethionine decarboxylase is much more active in brain.
• 3.3. The pattern of activity during development is different; only ornithine decarboxylase is very active during embryonal life; S-adenosylmethionine decarboxylase, at all events in brain, is more active in adult life.
• 4.4. Ornithine decarboxylase is inhibited in vitro by α-difluoromethylornithine, but not in vivo. Diaminopropane inhibits brain ornithine decarboxylase, but does not induce an ornithine decarboxylase-antizyme.
• 5.5. Methylglyoxal bis(guanylhydrazone) promotes an increase of S-adenosylmethionine decarboxylase activity in both the brain and the retina in vivo.

     

Novel tetraamines,pentaamines and hexaamines in sea urchin,sea cucumber,sea squirt and bivalves

• 1.1. Polyamines were extracted from the guts and ovaries of the sea urchin Anthocidoris crassispina, and the guts and flesh of the sea cucumber Stichopus japonicus and the sea squirt Halocynthia roretzi, the oyster Crassostrea gigas and the short-necked clam Tapes philippinarum, and analyzed by ion-exchange high-performance liquid chromatography and gas chromatography-mass spectrometry.
• 2.2. Norspermidine and norspermine as well as putrescine, cadaverine, spermidine, spermine and agmatine were the ubiquitous polyamines in these invertebrates. These results suggest the widespread distribution of norspermidine and norspermine in invertebrates.
• 3.3. Thermopentamine, thermohexamine and homothermohexamine were found in the sea urchin. This in the first report on the occurence of thermopentamine and hexaamine in invertebrates.
• 4.4. Homospermidine, canavalmine, aminopropylhomospermidine, homospermine, caldopentamine, homocaldopentamine and aminopropylcanavalmine were found in the sea cucumber. Homospermidine, aminopropylhomospermidine and homospermine were found in the squirt. This is the first report on the occurence of canavalmine, aminopropylhomospermidine, homospermine, homocaldopentamine and aminopropylcanavalmine in invertebrates.

     

The dependence of polyamine and phospholipid contents in marine bacteria on the osmotic strength of the medium

• 1.1. Marine bacteria MB 3, MB 28 and MB 45 contain the polyamines putrescine and spermidine, in amounts which are strongly dependent on the osmotic strength of the growth medium.
• 2.2. When the bacteria are transferred to a medium diluted 1:10, no lysis takes place, but a swelling, which is accompanied by a sudden increase in the amounts of both polyamines.
• 3.3. After reaching a maximum the polyamine content diminishes, followed by a slower increase.
• 4.4. During the growth in the diluted medium, the phospholipid content of the bacteria changes, and this change is correlated to the increase and decrease in the polyamine content.

     

Activity of some enzymes involved in the metabolism of polyamines in the liver of streptozotocin-diabetic rats

• 1.1. The effect of diabetes on some enzymes of polyamine metabolism was studied in male rats 1–12 days after administration of streptozotocin.
• 2.2. Hepatic ornithine decarboxylase activity decreased in the first days after the administration, but increased thereafter. The decrease was not due to an alteration of the ODC-antizyme concentration, nor to a posttranslational modification catalyzed by transglutaminase.
• 3.3. S-adenosylmethionine decarboxylase and ornithine transaminase were both increased.
• 4.4. Spermicline acetyltransferase activity was practically unchanged, while its inactivating factor was markedly decreased.

     

Inhibition of dihydrofolate reductase by palmitoyl coenzyme A

• 1.1. Palmitoyl-CoA was found to inhibit bovine liver dihydrofolate reductase.
• 2.2. 50% inhibition of the enzyme was obtained with 1.5 μM palmitoyl-CoA.
• 3.3. The inhibition was reversed by addition of bovine serum albumin, β-cyclodextrin or spermine.

     

Purification and characterization of hatching enzyme of the pike (Esox lucius)

• 1.1. A choriolytic enzyme was isolated from the hatching medium of the pike, Esox lucius.
• 2.2. The enzyme is defined as hatching enzyme.
• 3.3. The molecular weight of the enzyme is 24,000.
• 4.4. The enzyme is a glycoprotein containing 2% carbohydrate.
• 5.5. Its isoelectric point is 6.5.
• 6.6. The pH optimum is around pH 8.
• 7.7. The enzyme molecule contains two disulfide bonds but no free cysteine.
• 8.8. Inhibitor studies and metal analysis show that the enzyme is a zinc-metalloprotease.

     

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.

     

Novel polyamines in insects and spiders

• 1.1. Diaminopropane, putrescine, norspermidine, spesrmidine, norspermine and spermine were commonly found in the larval silk gland and head of Bombyx mori, Antheraea yamamai and Galleria mellonella.
• 2.2. The cockroach Periplaneta americana contained thermospermine, caldopentamine, caldohexamine, homospermidine, aminopropylhomospermidine and aminobutylhomospermidine (homospermine) in addition to the common polyamines. This is the first report to show the occurrence of the homospermidine derivatives and a hexamine in insects.
• 3.3. In addition to thermospermine, caldopentamine, agmatine, histamine, cadaverine and other usual polyamines, three cadaverine-derivatives, aminopropylcadaverine, bis(aminopropyl)cadaverine and aminopentylnorspermidine, were detected in the silk gland and head of the spiders, Nephila clavata and Araneus ventricosus. The occurrence of aminopropyl derivatives of of cadaverine has never been reported in animals.

     

The role of Zn2+ in pyridoxal phosphate mediated regulation of glutamic acid decarboxylase in brain

• 1.1. γ-Aminobutyric acid, a major inhibitory neurotransmitter in the CNS, is synthesized by glutamic acid decarboxylase which demonstrates an absolute requirement for pyridoxal phosphate.
• 2.2. At physiological concentrations, zinc stimulates the activity of pyridoxal kinase, enhancing the formation of pyridoxal phosphate, which in turn stimulates the activity of glutamic acid decarboxylase.
• 3.3. At pharmacological concentrations, zinc inhibits the activity of glutamic acid decarboxylase without inhibiting pyridoxal kinase.
• 4.4. These results suggest that zinc may play a role in pyridoxal phosphate-mediated regulation of glutamic acid decarboxylase.

     

Gender-related differences of mouse liver d-aspartate oxidase in the activity and response to administration of d-aspartate and peroxisome proliferators

• 1.1. The hepatic d-aspartate oxidase activity was found to be higher in female ddY and ICR mice than in their male counterparts. On the contrary, the free d-aspartate content in the liver was lower in female mice than in male mice, suggesting that d-aspartate is actually metabolized by d-aspartate oxidase in vivo.
• 2.2. Oral administration of d-aspartate to the animals increased the hepatic d-aspartate oxidase activity 2–3 fold in both genders without any significant difference in the rate of the increase between the genders.
• 3.3. Several peroxisomal enzyme activities other than d-aspartate oxidase examined were not affected by this treatment.
• 4.4. Experiments in vitro suggested that the increase in the d-aspartate activity might be explained in part by stabilization of the enzyme by d-aspartate.
• 5.5. The administration of clofibrate, a peroxisome proliferator, to male mice, increased the hepatic d-aspartate oxidase activity with a significant simultaneous decrease of d-aspartate content in the liver, in agreement with a possible role of the enzyme n vivo.
• 6.6. On the other hand, the administration of clofibrate or dehydroepiandrosterone to female mice decreased the d-aspartate oxidase activity.
• 7.7. The peroxisome proliferators were suggested to act to eliminate the gender difference of hepatic d-aspartate oxidase activity in mice.

     

S-Adenosyl-l-methionine decarboxylase activities in Mytilus edulis

• 1.1. The activities of S-adenosylmethionine decarboxylase (EC 4.1.1.50) were measured in cell extracts of mantle, hepatopancreas and foot from Mytilus edulis.
• 2.2. The apparent molecular weights of the enzymes estimated by gel filtration chromatography were 65,000 ± 10,000.
• 3.3. The enzymes do not require bivalent cations for catalysis and show optimum pH between 7.0–8.0 in phosphate buffer.
• 4.4. The hepatopancreas enzyme shows different behavior to the other two enzymes against temperature and its activity is strongly inhibited by NH₄⁺.
• 5.5. The apparent K_ms for S-adenosylmethionine were found to be 300, 200 and 250 μM for the hepatopancreas, mantle and foot enzymes, respectively.

     

In vivo effect of Berenil on rat liver polyamine metabolism

• 1.1. Berenil, administered to rats in vivo, promoted a decrease in liver SAMDC activity, but an increase in ODC and SAT activity.
• 2.2. Its effect on ODC was completely prevented by cycloheximide, that on SAT only partially.
• 3.3. Berenil had no effect on ODC activity in adrenalectomized rats. Adrenergic antagonists counteracted the effect of Berenil on ODC activity.
• 4.4. Polyamine content was increased. The maximum modification was observed for putrescine and N¹-acetylspermidine.

     

Evoked effects of oestradiol on hepatic cholesterol 7α-hydroxylase and drug oxidase in castrated rats

• 1.1. Oestradiol administration in castrated rats resulted in an increased activity of the cholesterolα-hydroxylase and a decreased activity of the drug oxidase enzyme systems.
• 2.2. Aqueous solutions of oestradiol (up to 25·10⁻⁶M) incubated in vitro with microsomes, binds into the microsomal membrane framework reducing the activity of both enzyme systems.
• 3.3. The specific activity of cholesterol 7α-hydroxylase. drops after 3 hr preincubation with oestradiol to at least 70% of its original value.
• 4.4. Actinomycin D and cycloheximide administration reduced the oestradiol-induced and control cholesterol 7α-hydroxylase activity to the same level, 6 hr after the injections.

     

Purification and characterization of the endonuclease present in Physalia physalis venom

• 1.1. Physalia physalis nematocyst venom contains a DNase which has a non-specific endonucleolytic action.
• 2.2. This enzyme has an approximate molecular weight of 75,000 daltons.
• 3.3. The enzyme can cleave DNA over a wide pH range with an optimum near neutrality.
• 4.4. The enzyme is thermolabile and its activity can be stimulated by 80 nM NaCl or 10 mM MgCl₂.