The A.A. have investigated the phospholipids base-exchange enzyme system in the solid tumours in ... more The A.A. have investigated the phospholipids base-exchange enzyme system in the solid tumours in order to state if a correlation between this activity and the variation of the cellular ciclic nucleotides amount was possible considering that these compounds have been reported to undergo a variation in tumour compared with normal tissues. They report some previous results in a lung tumour and in an endometrial carcinoma, were they have found a big increase in the PhS synthesis. Such increase was possible to be seen in the endometrial carcinoma only after a stimulation by 17-beta-estradiol and it was reversed in this case by doxorubicine. These results suggest that an alteration of the PhS synthesis should be one of numerous peculiarity of the neoplastic cell.
MM2 calculations have been performed on a number of derivatives of phorbol and diacylglycerol (DA... more MM2 calculations have been performed on a number of derivatives of phorbol and diacylglycerol (DAG) to establish the molecular features required for the activation of protein kinase C by a detailed comparison of the molecular geometries in these two classes of compounds. For DAG, a dihedral angle of about -60 degrees appears to be required for the oxygens at C2 and C3 because that angle is fixed at this value in phorbols. There is good agreement between the computed Boltzmann distribution for the O1-C1-C2-O2 dihedral angle and NMR results for the same angle in phospholipids, as obtained by others. A conformer of DAG is identified with dihedral angles corresponding to those of beta-phorbols. This conformer, however, is 3.2 kcal/mol above the global minimum found for DAG. The molecular geometry of this conformer is consistent with that of a number of active and inactive rigid analogues of DAG. The preferred conformation in beta-phorbol diesters is found to be stabilized by an antiparallel stacking of the ester carbonyl groups. The lack of activity of alpha-phorbol esters appears to be due to differences in a portion of the molecule containing the five-membered/seven-membered rings, which are far from the DAG-like end of the phorbol molecule. It is proposed that some of the biological activities of phorbol diesters may be due to this portion of the beta-phorbol molecule, which might represent a second active region, distinct from that resembling DAG.
: A decrease in protein kinase C activity caused either by treatment with inhibitors, such as sta... more : A decrease in protein kinase C activity caused either by treatment with inhibitors, such as staurosporine or H‐7, or by prolonged exposure to phorbol diesters has been proposed to be involved in the early events of SH‐SY5Y neuroblastoma cell differentiation. Because eight distinct isoforms of protein kinase C with discrete subcellular and tissue distributions have been described, we determined which isoforms are present in SH‐SY5Y cells and studied their modifications during differentiation. The α, β, δ, and ɛ isoforms were present in SH‐SY5Y cells, as well as in rat brain. Protein kinase C‐α and ‐β1 were the most abundant isoforms in SH‐SY5Y cells, and immunoreactive protein kinase C‐δ and ‐ɛ were present in much smaller amounts than in rat brain. Subcellular fractionation and immunocytochemistry demonstrated that all four isoforms are distributed bimodally in the cytoplasm and the membranes. Immunocytochemical analysis showed that the α isoform is associated predominantly with the plasma membrane and the processes extended during treatment with 12‐tetradecanoyl‐13‐acetyl‐β‐phorbol or staurosporine, and that protein kinase C‐ɛ is predominantly membrane‐bound. Its localization did not change during differentiation. Western blots of total SH‐SY5Y cell extracts and of subcellular fractions probed with isoform‐specific polyclonal antibodies showed that when SH‐SY5Y cells acquired a morphologically differentiated phenotype, protein kinase C‐α and ‐ɛ decreased, and protein kinase C‐β1, did not change. These data suggest distinct roles for the different protein kinase C isoforms during neuronal differentiation, as well as possible involvement of protein kinase α and ɛ in neuritogenesis.
The Journal of pharmacology and experimental therapeutics, 1990
The nonhydrolyzable guanyl nucleotide GTP gamma S stimulated phosphoinositidase C activity in two... more The nonhydrolyzable guanyl nucleotide GTP gamma S stimulated phosphoinositidase C activity in two preparations obtained from mouse pancreatic acini labeled with myo[2-3H]inositol: a cell-free membrane fraction and intact electropermeabilized acini. This action was dose-dependent, was shared by other nonhydrolyzable guanyl nucleotides such as GMP-phencyclidine hydrochloride and GMP-PMP, as well as by fluoride, and was calcium-independent. Contrarily, no effect was observed even at doses of GTP gamma S as high as 10 microM when the same protocol was repeated on identical acinar preparations from mice fed a choline-deficient, ethionine-supplemented diet. This regimen is known to uncouple secretagogue-receptor occupancy from inositol 1,4,5-trisphosphate generation in pancreatic acinar cells and lead to necrotizing hemorrhagic pancreatitis. These data lead us to conclude that the ethionine-induced inactivation of guanyl nucleotide-dependent pancreatic phosphoinositidase C in pancreatic a...
We have investigated the phosphatidylserine metabolism in human adenocarcinoma. This phospholipid... more We have investigated the phosphatidylserine metabolism in human adenocarcinoma. This phospholipid is involved in the regulation of several enzymic activities of plasma membranes; therefore it could be useful to state if some alteration of tumour membranes propriety depend on variation of phosphatidylserine synthesis. Our results make evident that in such human tumours the phosphatidylserine synthesis is greatly augmented.
Bowerbirds are large soft bills of the order Passeriformes, that inhabit New Guinea and Australia... more Bowerbirds are large soft bills of the order Passeriformes, that inhabit New Guinea and Australia! There are 18 species of bowerbirds, distributed among eight genera!·2 These birds are peculiar in that they have developed their building skills to an extreme degree, which they demonstrate in their courtship display object: the bower. Bowerbirds were discovered early after the first European settlers reached Australia, although they were not initially recognized as an independent group and were classified with the orioles and the honeysuckers~ Traditionally, these birds have been considered relatives of the birds of paradise. However, recent DNA studies suggest that they are more closely related to the wattlebirds of New Zealand (family Callaeidae), the starlings and the Corvine assemblage? Bowerbirds are not common avicultural .subjects, but they are frequently present in well stocked zoos. They are rare in aviculture primarily because their two main sources - Australia and Papua New...
Earlier studies have indicated that lysosomal enzymes such as cathepsin B become redistributed wi... more Earlier studies have indicated that lysosomal enzymes such as cathepsin B become redistributed within pancreatic acinar cells during the early stages of both diet- and secretagogue-induced acute pancreatitis. As a result, cathepsin B and digestive zymogens became colocalized within large cytoplasmic vacuoles. As cathepsin B can activate trypsinogen, this colocalization could result in intracellular digestive enzyme activation. The present study investigates the protective effects of gabexate mesilate (FOY) and camostate (FOY 305) on both of these noninvasive models of experimental pancreatitis. These esterase inhibitors prevented the hyperamylasemia, pancreatic edema, and acinar cell vacuolization that characterize secretagogue-induced pancreatitis and the hyperamylasemia and mortality that characterize diet-induced pancreatitis. In addition, FOY and FOY 305 were found to significantly decrease the subcellular redistribution of cathepsin B that occurs in both models. These findings ...
Although I am not a large-scale breeder and exhibitor of finches, I have accepted the invitation ... more Although I am not a large-scale breeder and exhibitor of finches, I have accepted the invitation of the editor to write this article on the management and breeding of the Gouldian Finch with great pleasure. This is because the information on breeding, foster parenting, artificial incubation and, particularly, handrearing from egg of this species is also relevant for many other species of finches, including the most demanding of the waxbills. This article focuses on the biology, management and breeding of the Lady Gould Finch (Chloebia gouldiae). The special problems presented to the aviculturist by the frequent failure of Gouldian parents to incubate and/ or raise their offspring is, as we will see later, not completely negative, but may, under certain circumstances, carry positive consequences for the husbandry of this species. Biology of the Gouldian Finch Many books and innumerable articles cover the biology of the heterogeneous bird compound called finches. Here I will restrict ...
Fig parrots are an interesting group of birds of which very little is known. They belong to the f... more Fig parrots are an interesting group of birds of which very little is known. They belong to the family Psittacidae and are, therefore, true parrots. "Fig parrot" is, in fact, a conventional name without scientific basis. The group includes two genera, the Opopsitta and the Psittaculirostris. The two groups are very similar in their biology and have many common features. The Opopsitta are smaller birds and were known in aviculture, though as a rarity, since the beginning of the century. The Psittaculirsotris were virtually unknown until the beginning of the '70s. The information about both genera is very scant. In Parrots of the World) Forshaw gives some basic information about their habits, but nothing about breeding. Rosemary Low has a detailed chapter in one of her books; written with the aviculturist's point of view, and reports whatever was known in 1983. However, even that does not totally reassure the aviculturist challenged by the keeping of these species. A...
The honeycreepers, sometimes called sugarbirds, are a heterogeneous group of birds from South Ame... more The honeycreepers, sometimes called sugarbirds, are a heterogeneous group of birds from South America that have been known to bird fanciers for a long time. These beautiful, gracious birds have been somewhat overlooked in the last 40 years by aviculturists. The purpose of this article is to remind the modern bird lover of the existence of these birds, and of their potential as aviculrural subjects. In this article I will not attempt to cover the very distinct aggregate of the Hawaiian honeycreepers (Drepanididae) that constitute a separate group. The biology of these birds, some of which are extinct, and all the living species endangered, is covered in a comprehensive article elsewhere! However, the information that I will present in this article can be of use in the management, husbandry and establishment of other small nectar-eaters with biology similar to the South American honeycreepers, namely the sunbirds from the Old World (Nectariniidae), the small honeyeaters from Australia...
Journal of chromatography. B, Biomedical applications, Jan 19, 1994
We performed detailed chromatographic analyses on the molecular species of the major glycerophosp... more We performed detailed chromatographic analyses on the molecular species of the major glycerophospholipids (GPLs) and free sn-1,2-diacylglycerols (DAGs) from SH-SY5Y human neuroblastoma cells following incubation with or without LiCl. For this comparison the inositol, choline, ethanolamine and serine GPLs were dephosphorylated with phospholipase C and the released sn-1,2-diacylglycerols along with the DAGs were subjected to high-temperature GLC on polar and non-polar capillary columns as their trimethylsilyl and tert.-butyl-dimethylsilyl ethers. A 30-min incubation with 10 mM LiCl increased the total amount of human neuroblastoma DAGs by 32-58% (P < 0.05) to 2.6 pmol/micrograms cell protein. This was accompanied by a limited qualitative shift in the molecular species pattern, the most obvious of which was the increase (13%) in the major saturated-polyunsaturated molecular species and the ca. 46% increase in the minor 18:1-18:1 species over control levels. The DAGs originated mainl...
The A.A. have investigated the phospholipids base-exchange enzyme system in the solid tumours in ... more The A.A. have investigated the phospholipids base-exchange enzyme system in the solid tumours in order to state if a correlation between this activity and the variation of the cellular ciclic nucleotides amount was possible considering that these compounds have been reported to undergo a variation in tumour compared with normal tissues. They report some previous results in a lung tumour and in an endometrial carcinoma, were they have found a big increase in the PhS synthesis. Such increase was possible to be seen in the endometrial carcinoma only after a stimulation by 17-beta-estradiol and it was reversed in this case by doxorubicine. These results suggest that an alteration of the PhS synthesis should be one of numerous peculiarity of the neoplastic cell.
MM2 calculations have been performed on a number of derivatives of phorbol and diacylglycerol (DA... more MM2 calculations have been performed on a number of derivatives of phorbol and diacylglycerol (DAG) to establish the molecular features required for the activation of protein kinase C by a detailed comparison of the molecular geometries in these two classes of compounds. For DAG, a dihedral angle of about -60 degrees appears to be required for the oxygens at C2 and C3 because that angle is fixed at this value in phorbols. There is good agreement between the computed Boltzmann distribution for the O1-C1-C2-O2 dihedral angle and NMR results for the same angle in phospholipids, as obtained by others. A conformer of DAG is identified with dihedral angles corresponding to those of beta-phorbols. This conformer, however, is 3.2 kcal/mol above the global minimum found for DAG. The molecular geometry of this conformer is consistent with that of a number of active and inactive rigid analogues of DAG. The preferred conformation in beta-phorbol diesters is found to be stabilized by an antiparallel stacking of the ester carbonyl groups. The lack of activity of alpha-phorbol esters appears to be due to differences in a portion of the molecule containing the five-membered/seven-membered rings, which are far from the DAG-like end of the phorbol molecule. It is proposed that some of the biological activities of phorbol diesters may be due to this portion of the beta-phorbol molecule, which might represent a second active region, distinct from that resembling DAG.
: A decrease in protein kinase C activity caused either by treatment with inhibitors, such as sta... more : A decrease in protein kinase C activity caused either by treatment with inhibitors, such as staurosporine or H‐7, or by prolonged exposure to phorbol diesters has been proposed to be involved in the early events of SH‐SY5Y neuroblastoma cell differentiation. Because eight distinct isoforms of protein kinase C with discrete subcellular and tissue distributions have been described, we determined which isoforms are present in SH‐SY5Y cells and studied their modifications during differentiation. The α, β, δ, and ɛ isoforms were present in SH‐SY5Y cells, as well as in rat brain. Protein kinase C‐α and ‐β1 were the most abundant isoforms in SH‐SY5Y cells, and immunoreactive protein kinase C‐δ and ‐ɛ were present in much smaller amounts than in rat brain. Subcellular fractionation and immunocytochemistry demonstrated that all four isoforms are distributed bimodally in the cytoplasm and the membranes. Immunocytochemical analysis showed that the α isoform is associated predominantly with the plasma membrane and the processes extended during treatment with 12‐tetradecanoyl‐13‐acetyl‐β‐phorbol or staurosporine, and that protein kinase C‐ɛ is predominantly membrane‐bound. Its localization did not change during differentiation. Western blots of total SH‐SY5Y cell extracts and of subcellular fractions probed with isoform‐specific polyclonal antibodies showed that when SH‐SY5Y cells acquired a morphologically differentiated phenotype, protein kinase C‐α and ‐ɛ decreased, and protein kinase C‐β1, did not change. These data suggest distinct roles for the different protein kinase C isoforms during neuronal differentiation, as well as possible involvement of protein kinase α and ɛ in neuritogenesis.
The Journal of pharmacology and experimental therapeutics, 1990
The nonhydrolyzable guanyl nucleotide GTP gamma S stimulated phosphoinositidase C activity in two... more The nonhydrolyzable guanyl nucleotide GTP gamma S stimulated phosphoinositidase C activity in two preparations obtained from mouse pancreatic acini labeled with myo[2-3H]inositol: a cell-free membrane fraction and intact electropermeabilized acini. This action was dose-dependent, was shared by other nonhydrolyzable guanyl nucleotides such as GMP-phencyclidine hydrochloride and GMP-PMP, as well as by fluoride, and was calcium-independent. Contrarily, no effect was observed even at doses of GTP gamma S as high as 10 microM when the same protocol was repeated on identical acinar preparations from mice fed a choline-deficient, ethionine-supplemented diet. This regimen is known to uncouple secretagogue-receptor occupancy from inositol 1,4,5-trisphosphate generation in pancreatic acinar cells and lead to necrotizing hemorrhagic pancreatitis. These data lead us to conclude that the ethionine-induced inactivation of guanyl nucleotide-dependent pancreatic phosphoinositidase C in pancreatic a...
We have investigated the phosphatidylserine metabolism in human adenocarcinoma. This phospholipid... more We have investigated the phosphatidylserine metabolism in human adenocarcinoma. This phospholipid is involved in the regulation of several enzymic activities of plasma membranes; therefore it could be useful to state if some alteration of tumour membranes propriety depend on variation of phosphatidylserine synthesis. Our results make evident that in such human tumours the phosphatidylserine synthesis is greatly augmented.
Bowerbirds are large soft bills of the order Passeriformes, that inhabit New Guinea and Australia... more Bowerbirds are large soft bills of the order Passeriformes, that inhabit New Guinea and Australia! There are 18 species of bowerbirds, distributed among eight genera!·2 These birds are peculiar in that they have developed their building skills to an extreme degree, which they demonstrate in their courtship display object: the bower. Bowerbirds were discovered early after the first European settlers reached Australia, although they were not initially recognized as an independent group and were classified with the orioles and the honeysuckers~ Traditionally, these birds have been considered relatives of the birds of paradise. However, recent DNA studies suggest that they are more closely related to the wattlebirds of New Zealand (family Callaeidae), the starlings and the Corvine assemblage? Bowerbirds are not common avicultural .subjects, but they are frequently present in well stocked zoos. They are rare in aviculture primarily because their two main sources - Australia and Papua New...
Earlier studies have indicated that lysosomal enzymes such as cathepsin B become redistributed wi... more Earlier studies have indicated that lysosomal enzymes such as cathepsin B become redistributed within pancreatic acinar cells during the early stages of both diet- and secretagogue-induced acute pancreatitis. As a result, cathepsin B and digestive zymogens became colocalized within large cytoplasmic vacuoles. As cathepsin B can activate trypsinogen, this colocalization could result in intracellular digestive enzyme activation. The present study investigates the protective effects of gabexate mesilate (FOY) and camostate (FOY 305) on both of these noninvasive models of experimental pancreatitis. These esterase inhibitors prevented the hyperamylasemia, pancreatic edema, and acinar cell vacuolization that characterize secretagogue-induced pancreatitis and the hyperamylasemia and mortality that characterize diet-induced pancreatitis. In addition, FOY and FOY 305 were found to significantly decrease the subcellular redistribution of cathepsin B that occurs in both models. These findings ...
Although I am not a large-scale breeder and exhibitor of finches, I have accepted the invitation ... more Although I am not a large-scale breeder and exhibitor of finches, I have accepted the invitation of the editor to write this article on the management and breeding of the Gouldian Finch with great pleasure. This is because the information on breeding, foster parenting, artificial incubation and, particularly, handrearing from egg of this species is also relevant for many other species of finches, including the most demanding of the waxbills. This article focuses on the biology, management and breeding of the Lady Gould Finch (Chloebia gouldiae). The special problems presented to the aviculturist by the frequent failure of Gouldian parents to incubate and/ or raise their offspring is, as we will see later, not completely negative, but may, under certain circumstances, carry positive consequences for the husbandry of this species. Biology of the Gouldian Finch Many books and innumerable articles cover the biology of the heterogeneous bird compound called finches. Here I will restrict ...
Fig parrots are an interesting group of birds of which very little is known. They belong to the f... more Fig parrots are an interesting group of birds of which very little is known. They belong to the family Psittacidae and are, therefore, true parrots. "Fig parrot" is, in fact, a conventional name without scientific basis. The group includes two genera, the Opopsitta and the Psittaculirostris. The two groups are very similar in their biology and have many common features. The Opopsitta are smaller birds and were known in aviculture, though as a rarity, since the beginning of the century. The Psittaculirsotris were virtually unknown until the beginning of the '70s. The information about both genera is very scant. In Parrots of the World) Forshaw gives some basic information about their habits, but nothing about breeding. Rosemary Low has a detailed chapter in one of her books; written with the aviculturist's point of view, and reports whatever was known in 1983. However, even that does not totally reassure the aviculturist challenged by the keeping of these species. A...
The honeycreepers, sometimes called sugarbirds, are a heterogeneous group of birds from South Ame... more The honeycreepers, sometimes called sugarbirds, are a heterogeneous group of birds from South America that have been known to bird fanciers for a long time. These beautiful, gracious birds have been somewhat overlooked in the last 40 years by aviculturists. The purpose of this article is to remind the modern bird lover of the existence of these birds, and of their potential as aviculrural subjects. In this article I will not attempt to cover the very distinct aggregate of the Hawaiian honeycreepers (Drepanididae) that constitute a separate group. The biology of these birds, some of which are extinct, and all the living species endangered, is covered in a comprehensive article elsewhere! However, the information that I will present in this article can be of use in the management, husbandry and establishment of other small nectar-eaters with biology similar to the South American honeycreepers, namely the sunbirds from the Old World (Nectariniidae), the small honeyeaters from Australia...
Journal of chromatography. B, Biomedical applications, Jan 19, 1994
We performed detailed chromatographic analyses on the molecular species of the major glycerophosp... more We performed detailed chromatographic analyses on the molecular species of the major glycerophospholipids (GPLs) and free sn-1,2-diacylglycerols (DAGs) from SH-SY5Y human neuroblastoma cells following incubation with or without LiCl. For this comparison the inositol, choline, ethanolamine and serine GPLs were dephosphorylated with phospholipase C and the released sn-1,2-diacylglycerols along with the DAGs were subjected to high-temperature GLC on polar and non-polar capillary columns as their trimethylsilyl and tert.-butyl-dimethylsilyl ethers. A 30-min incubation with 10 mM LiCl increased the total amount of human neuroblastoma DAGs by 32-58% (P < 0.05) to 2.6 pmol/micrograms cell protein. This was accompanied by a limited qualitative shift in the molecular species pattern, the most obvious of which was the increase (13%) in the major saturated-polyunsaturated molecular species and the ca. 46% increase in the minor 18:1-18:1 species over control levels. The DAGs originated mainl...
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