Complementation of the pina (null) allele with the wild type Pina sequence restores a soft phenotype in transgenic wheat.

The tightly linked puroindoline genes, Pina and Pinb, control grain texture in wheat, with wild type forms of both giving soft, and a sequence alteration affecting protein expression or function in either giving rise to hard wheat. Previous experiments have shown that addition of wild type Pina in the presence of mutated Pinb gave intermediate grain texture but addition of wild type Pinb gave soft grain. This raises questions as to whether Pina may be less functional than Pinb. Our goal here was to develop and characterize wheat lines expressing the wild type Pina-D1a sequence in hard wheat with the null mutation (Pina-D1b) for Pina. Three transgenic lines plus Bobwhite were evaluated in two environments. Grain texture, grain protein, and kernel weight were determined for the transgenic lines and Bobwhite. The three transgenic lines had soft phenotype, and none of the transgenic lines differed from Bobwhite for grain protein or kernel weight. The soft phenotype was accompanied by increases in Pina transcript accumulation. Total Triton X-114 extractable PINA and PINB increased from 2.5 to 5.5 times those from a soft wheat reference sample, and friabilin, PINA and PINB bound to starch, increased from 3.8 to 7.8 times those of the soft wheat reference. Bobwhite showed no starch bound PINA, but transgenic lines had levels from 5.3 to 13.7 times those of the soft wheat reference sample. Starch bound PINB in transgenic lines also increased from 0.9 to 2.5 times that for the soft wheat reference sample. The transgenic expression of wild type Pina sequence in the Pina null genotype gave soft grain with the characteristics of soft wheat including increased starch bound friabilin. The results support the hypothesis that both wild type Pin genes need to be present for friabilin formation and soft grain.

[Release of pancreatic polypeptide induced by cholecystokinin in man and dog]. / Libération du polypeptide pancréatique par la cholécystokinine chez l'homme et chez le chien.

In four healthy volunteers increasing doses of intravenous CCK-33 induced an increase in plasma PP concentration measured by RIA. PP concentration rose from a basal level of 67 +/- 15 pmol/l to 198 +/- 45 pmol/l with 2 IDU/kg/h (p less than 0.05). In four mongrel dogs equipped with Thomas cannulas, the same doses induced a more pronounced rise in plasma PP (p less than 0.01). It is concluded that intravenous CCK-33 induces the release of PP in man and dog in a dose-dependent manner.

The release of pancreatic polypeptide by CCK-octapeptide and some analogues in the dog.

In dogs with gastric and pancreatic Thomas fistulas the effect of different cholecystokinin-like peptides upon pancreatic polypeptide (PP) release was studied in three ways: (a) Plasma PP concentrations were determined by radioimmunoassay in response to 135 pmol/kg/h of the synthetic C-terminal octapeptide of cholecystokinin (CCK-OP) (A), of three of its analogues (B, C, D) where methionine has been replaced by methoxinine, and in response to 45 pmol/kg/h of caerulein. The greatest rise in plasma PP concentration expressed as delta PP was achieved with caerulein (327 +/- 37 pM), when taking into account the threefold smaller dose used, followed by CCK-OP (536 +/- 67 pM) and analogues B (343 +/- 51 pM), C (87 +/- 46 pM), and D (32 +/- 15 pM). The order of potency with respect to stimulation of exocrine pancreatic secretion was the same: E and A precede B, C, and D. delta PP correlated linearly with the pancreatic protein output (r = 0.98, p less than 0.01). (b) CCK-OP was infused in four doses of 35, 70, 135, and 270 pmol/kg/h, and plasma PP concentrations and exocrine pancreatic secretion were monitored. The correlation between pancreatic protein output and delta PP was very close (r = 0.98, p less than 0.01). (c) Atropine sulfate (0.1 mg/kg, i.v.) reduced the PP response to the 135 pmol/kg/h dose of CCK-OP by 61%. We conclude from this that CCK-OP and related peptides do release PP and that their effect on exocrine pancreatic secretion is closely correlated with their PP-releasing capacity. The PP release may therefore be used as an indicator of the CCK-like activity of CCK fragments and analogues. CCK-OP may well represent one of the humoral stimulatory factors contributing to the release of PP, but this action appears to depend on a cholinergic background.

Biological activity of the C-terminal octapeptide of cholecystokinin, of three of its analogues and of caerulein in the dog.

Dose-response curves of the C-terminal octapeptide (CCK-8) of cholecystokinin, of 3 of its methoxinine analogues, and of caerulein for various variables of exocrine pancreatic secretion have been established in conscious dogs. The following relative potencies were calculated for the protein secretion activity of CCK-8 (100%), [Mox3]-CCK-8 (52%), [Mox6]-CCK-8 (27%), [Mox3,Mox6]-CCK-8 (19%) and caerulein (178%).

[Caerulein and the test meal: a comparison of their effects on pancreatic exocrine secretion in the dog]. / Caeruléine et repas d'épreuve: comparaison de leurs effets sur la sécrétion pancréatique exocrine chez le chien.

Relatively small doses of caerulein (10, 20, 40, 100 ng/kg/h) were given to conscious dogs with chronic duodenal and gastric fistulas and the exocrine pancreatic response was compared with that obtained by a test meal. Test meal stimulated pancreatic secretion was nearly equivalent to that achieved with 10 ng caerulein/kg/h. Plasma secretin levels did not significantly change during test meal stimulation.