Organization of fusicoccin receptor in higher plant plasma membrane: relationship between affinity and molecular mass

Higher plant plasma membranes carry receptors of different affinity for the phytotoxin fusicoccin. Reception of fusicoccin involves proteins belonging to the highly conserved 14-3-3 family, but the complete structure of the fusicoccin receptor (FCR) is unknown. Using radiation inactivation analysis, we estimated the molecular masses of low-affinity and high-affinity FCR at 63 +/- 7 and 130 +/- 15 kD, respectively. The dose dependences of receptor inactivation indicate that microsomal specimens contain "silent" FCRs of 420 +/- 90 kD in amounts commensurate with that of the active FCRs. Both low- and high-affinity FCRs are inactivated by hydrolytic enzymes from the outer surface of the plasma membrane, and impairment of protoplast integrity causes an irreversible transition of the low-affinity binding site into the high-affinity one. A scheme is proposed for the organization of different types of FCR in the plasma membrane, implying that the membrane affinity for fusicoccin reflects the interaction between proteins in the FCR complex.     

Effect of prostaglandin F2α on uterine or ovarian secretion of prostaglandins E and F2α in vivo in 90–100 day hysterectomized, intact or ovariectomized pregnant ewes

Vehicle or 8 or 16 mg of PGF_2α per 58 kg body weight was given intramuscularly to intact, hysterectomized or ovariectomized 90–100 day pregnant ewes in three separate experiments. Both doses of PGF_2α increased PGF_2α in ovarian venous plasma compared with controls at 72 hr post treatment in intact (P≤0.05) but did not in hysterectomized (P≥0.05) 90–100 day pregnant ewes. Concentrations of PGE in ovarian venous blood of intact ewes did not differ (P≥0.05) between treatment groups and were equivalent to concentrations of PGE determined in uterine venous plasma. PGE was decreased in ovarian venous plasma by PGF_2α in hysterectomized ewes (P≤0.07). PGE in uterine venous plasma averaged 6 ng/ml over the 72-hr treatment period in intact and ovariectomized 90–100 day pregnant ewes and was 12 fold greater (P≤0.05) than PGF_2α which averaged 500 pg/ml in uterine venous plasma. Both PGF_2α and PGE increased (P≤0.05) by 64 hr in uterine venous plasma of the 8 mg PGF_2α — treated intact pregnant ewes. A significant quadratic increase (P≤0.05) was observed for PGF_2α and PGE in the vehicle and both PGF_2α treatment groups of intact ewes at the end of the 72-hr sampling period. It is concluded that the uterus and ovaries secrete significant quantities of PGE but little PGF_2α during midgestation. In addition, PGF_2α increased uterine secretion of PGE . PGE may be a placental stimulator of ovine placental secretion of progesterone or PGE may protect placental steroidogenesis from actions of PGF_2α.     

Autonomic innervation and plasma estradiol-17β and progesterone levels in rats with subcutaneous ovarian autografts

Summary Ovaries were removed from female rats and immediately autografted into a subcutaneous pouch in the flank in order to quantitate the relationship of graft re-innervation, steroid secretion and vaginal smear pattern. Animals were killed at three time periods: three days after grafting, on the first day a cornified vaginal smear appeared and at the first metestrus. In addition, control animals were killed at metestrus. Plasma samples were obtained from all rats and analyzed for estradiol-17 and progesterone concentration by radioimmunoassay.At the first day of vaginal cornification after grafting, plasma estradiol-17 (45.8±4.0 pg/ml) was elevated in comparison to controls at metestrus (24.0±2.6 pg/ml), but plasma progesterone (21.5±4.0 ng/ml) was not different (30.6±1.7 ng/ml). Subsequently, at the first metestrus following grafting, plasma estradiol-17 (23.0±3.5 pg/ml) was comparable to control values. In contrast, progesterone was decreased (17.5±1.9 ng/ml). A definite correlation was detected between the vaginal smear and plasma levels of steroid hormones in the castrated female rat with subcutaneous ovarian autografts.Histochemical techniques were used to study the adrenergic and cholinergic innervations of grafts three days after grafting, at the first day of vaginal cornification, and at the first metestrus. No correlation was shown between density of adrenergic or cholinergic innervation and plasma levels of estradiol-17 and progesterone or onset of a cycling vaginal smear.Supported in part by USPHS Grant T01-DE00241-04The authors wish to thank J. Canale, S. Hemelt, E. Schwartz and J. Skaggs for their technical and secretarial assistance. Anti-estradiol-17 antibody was obtained from Dr. I.H. Thorneycroft, University of Southern California School of Medicine, and anti-progesterone antibody from Dr. D. Tulchinsky, Harvard Medical Center     

Effect of PGE1 on PGF2 alpha-induced luteolysis in nonbred ewes

Fifty-six ewes were used to study the effects of PGE1 or PGE2 plus PGF2 alpha given into the perivascular space of the ovarian vascular pedicle on luteal function of nonbred ewes. All ewes receiving PGF2 alpha had reduced levels of plasma progesterone and unoccupied receptors for LH at 24 hr after treatment regardless even if they received PGE1 or PGE2 concomitantly. Levels of plasma progesterone in ewes receiving only PGF2 apha were reduced further at 48 hour. Plasma progesterone and unoccupied receptors for LH of ewes receiving PGE2 + PGF2 alpha were maintained at 48 hr at levels seen at 24 hr after treatment, while progesterone in ewes receiving PGE1 + PGF2 alpha at 48 hr returned to levels seen in controls at 48 hr and unoccupied receptors for LH were three fold greater than controls.     

Prostaglandins F in uterine and ovarian venous plasma from nonpregnant and pregnant ewes collected by cannulation.

Periodic collections of uterine venous blood were obtained from three nonmated, three pregnant and two mated but nonpregnant ewes in which uterine veins were cannulated with polyvinyl tubing on day 11 postestrus. Frequent sampling was achieved in three of these ewes with additional cannulae in the ovarian veins. Blood samples were collected at 3-hr intervals from 0600 on day 12 to 1800 on day 13 and then 6-hr intervals through day 15. On day 13, three additional samples at 30-min intervals were collected between 1400 and 1530. Prostaglandins F (PGF) in plasma were quantified by radioimmunoassay. On day 12, one ewe in each group had at least one measurement which suggested an increased rate of release of PGF into the uterine vein. Seven of eight ewes on day 13 appeared to have increased rates of release of PGF from the uterus between 0900 and 1500. The highest level measured in each ewe during this period ranged from 2.7 to 11 ng per milliliter. Concentrations of PGF in ovarian venous plasma in two of three ewes were positively correlated (P less than .05) with concentrations of PGF in uterine venous plasma (r equals .64 in each ewe). No evidence was obtained that pregnant and nonpregnant ewes differ in rate or pattern of release of PGF from the uterus into the uterine vein on days 12 and 13. Comparisons could not be made with confidence concerning PGF either in uterine veins on days 14 and 15 or in ovarian veins on all days due to limited number of observations.     

Ultraviolet-induced thymine hydrates in DNA are excised by bacterial and human DNA glycosylase activities

Ultraviolet irradiation of DNA results in various pyrimidine modifications. We studied the excision of an ultraviolet thymine photoproduct by Escherichia coli endonuclease III and by a preparation of human WI-38 cells. These enzymes cleave UV-irradiated DNA at apyrimidinic sites formed by glycosylic removal of the photoproduct. Poly(dA-[3H]dT).poly(dA-[3H]dT) was UV irradiated and incubated with purified E. coli endonuclease III. 3H-Containing material was released in a manner consistent with Michaelis-Menten kinetics. This 3H-labeled material was determined to be a mixture of thymine hydrates (6-hydroxy-5,6-dihydrothymine), separable from unmodified thymine by chromatography in three independent systems. Both cis-thymine hydrate and trans-thymine hydrate were chemically and photochemically synthesized. These coeluted with the enzyme-released 3H-containing material. No thymine glycol was released from the UV-irradiated polymer. Similar results were obtained with extracts of WI-38 cells as the enzyme source. The release of thymine hydrates by both glycosylase activities was directly proportional to the amount of enzyme and the irradiation dose to the DNA substrate. These results demonstrate the modified thymine residues recognized and excised by endonuclease III and the human enzyme to be a mixture of cis-thymine hydrate and trans-thymine hydrate. The reparability of these thymine hydrates suggests that they are stable in DNA and therefore potentially genotoxic.     

Effects of PGE1 or PGE2 on luteal function in pseudopregnant rats

Effects of PGE1 or PGE2 on luteal function were studied in 163 pseudopregnant rats. PGE1 (10, 100, or 300 micrograms) given intrauterine every 6 hr did not shorten pseudopregnancy (P greater than 0.05), however, the same doses of PGE2 given intrauterine every 6 hr advanced luteolysis (P less than 0.05). PGE1 (100 or 300 micrograms) given every 4 hr intramuscular maintained levels of progesterone in peripheral blood above controls (P less than 0.05) while 100 or 300 micrograms of PGE2 hastened the decline in progesterone (P less than 0.05). The antiluteolytic effect of PGE1 was not via an inhibition of PGF secretion (P greater than 0.05) by the uterus or by induction of ovulation in treated animals. Moreover, PGE1 (100, 200, or 500 micrograms) given intramuscular every 4 hr from day 4 of pseudopregnancy until the next proestrus delayed luteal regression around 3 days (P less than 0.05). PGE2 at doses of 100, 200, or 500 micrograms every 4 hr given intramuscular consistently shortened pseudopregnancy (P less than 0.05). Lower doses were without effect (P greater than 0.05). Based on the above data it is concluded that PGE2 is consistently luteolytic whereas PGE1 is not luteolytic in pseudopregnant rats and that PGE1 may be an antiluteolysin.     

反相高效液相层析法测定新鲜植物材料中的植物雌激素含量

通过适当的样品处理方法,游离的和结合的植物雌激素［大豆素,雌马酚,染料木素,芒柄花素,香豆雌酚和美皂异黄酮］被从新鲜植物材料的提取物中分离出来,并在不同的紫外光波长下,可被ＨＰＬＣ法定量测定,根据滞留时间和标准品的添加,而鉴别出植物雌激素的层析波峰。本方法的测定灵敏度为２ｐｐｍ。白三叶草样品的加样回收率在８０％－１００％之间（平均回收率变异系数为５．４％）。通过比较游离植物雌激素的含量测定,本方法