Corticotropin releasing factor decidualizes human endometrial stromal cells in vitro. Interaction with progestin

Decidualization of endometrial cells is a hormone-dependent process of differentiation which occurs during the menstrual cycle and pregnancy. Recent in vitro studies have revealed that cAMP and its generators induce decidualization of stromal cells isolated from proliferative endometrium and that progestins enhance the effect of cAMP. Since corticotropin releasing factor (CRF) generates cAMP and prostaglandins in other organs, in the present study the effect of CRF, a hypothalamic factor also produced by decidua and fetal membranes, on in vitro decidualization of endometrial stromal cells was evaluated. The addition of CRF to a culture medium of stromal cells induced in vitro decidualization, as indicated by morphologic changes from elongated fibroblast-like cells into larger and round cells and by the release of prolactin in the medium. The effect of CRF on stromal cells and on prolactin release was significantly augmented by the coincubation in the presence of medroxyprogesterone acetate. This observation indicates CRF as a novel factor of decidualization and confirms that progestins act as enhancers of the expression of decidual products.     

Displacement of O2 and CO by cyanide from the active site of helix pomatia β-hemocyanin.: Formation of a mixed-liganded species

Addition of KCN to Helix pomatia β-hemocyanin fully saturated with either O₂ or CO results in a decrease of the spectroscopic properties of the protein (absorbance at 340 nm and luminescence at 550 nm) due to the displacement of the gaseous ligands (O₂ or CO) from the active site. The anionic form of cyanide (CN^?) is supposed to bind to the active site; its intrinsic affinity for the protein, as calculated from independent O₂ and CO displacement experiments, is between 2 and 6 × 10⁶M^?1. The replacement of O₂ or CO shows some differences which may be correlated with the different modes of binding at the active site. Thus, while displacement of oxygen by cyanide is hyperbolic, addition of cyanide to carbonylated hemocyanin shows a lag phase. This finding suggests the formation of a mixed liganded complex at the active site. The simultaneous presence of CO and CN^? at the active site of hemocyanin is also supported by the experiment in which addition of small amounts of KCN to hemocyanin partially saturated with O₂ and CO gives rise to an increase of emission intensity and a concomitant decrease of the O₂ absorption band. The mixed-liganded species displays luminescence properties similar to those of CO-saturated hemocyanin, and the formation of the complex is reversible on dialysis or oxygenation.     

Phaseolus vulgaris phytohemagglutinin contains high-mannose and modified oligosaccharide chains

Phytohemagglutinin, the major lectin in the seeds of the common bean Phaseolus vulgaris L., was isolated by affinity chromatography from cotyledons of nearly mature seeds and from developing cotyledons labeled with [³H]glucosamine, [³H]mannose or [³H]fucose. The protein was subjected to exhaustive proteolysis and the carbohydrate composition of the resulting glycopeptides examined. Two classes of oligosaccharide side-chains were found. The sidechains of the first class are of the high-mannose type, containing two residues of N-acetylglucosamine and 8 or 9 mannose residues. The sidechains of the second class are of the modified type containing N-acetylglucosamine, mannose, fucose, xylose in molar ratios of 2:3.8:0.6:0.5. Two-dimensional gel electrophoresis shows that phytohemagglutinin can be fractionated into seven different glycosylated polypeptides, and that each one contains at least one modified oligosaccharide chain. The results indicate that most glycosylated polypeptides probably contain one chain of each class. The carbohydrate composition of the two types of chains is similar to that found in other plant glycoproteins, but this is the first report of a plant glycoprotein with both highmannose and modified oligosaccharides on the same polypeptide chain.Abbreviations endo H endo--N-acetylglucosaminidase H - GlcN glucosamine - GlcNAc N-acetylglucosamine - Man mannose - PHA phytohemagglutinin This work was done while A.V. was on leave from the Istituto Biosintesi Vegetali, C.N.R., via Bassini 15, I-20133 Milano, Italy     

Synergistic effect of phosphatidylserine with γ-aminobutyric acid in antagonizing the isoniazid-induced convulsions in mice

The influence of phosphatidylserine (PS) on the isoniazid-induced convulsions has been studied in mice. Sonicated dispersions of this phospholipid given intravenously do not show anticonvulsant activity but they do so when -aminobutyric acid (GABA) is simultaneously injected. GABA alone is inactive. The synergism between PS and GABA is influenced by the structure of the phospholipid liposomes. In contrast to multilamellar vesicles, oligolamellar vesicles are active. Under these conditions the effect shows head group specificity, in that the neutral phosphatidylcholine (PC) or the acidic phosphatidylinositol (PI) are inactive, either in the presence or in the absence of GABA. Lysophosphatidylserine (lysoPS), the deacylated PS derivative, shows increased efficacy as an isoniazid antagonist in the presence of GABA, and has anticonvulsant activity also in the absence of GABA. Other lysophospholipids are inactive. It is suggested that PS, after its metabolic conversion to lysoPS, enhances the anticonvulsant effect of GABA.     

Correlation of cotylenol with the aglycone of fusicoccin

The stereostructure of cotylenol, the aglycone of the cotylenins, has been confirmed by chemical correlation with the aglycone of fusicoccin A.     

Syndrome +12p

Summary Familial 12/15 translocation with a child trisomic for the short arm of chromosome 12 (segment p 12.1pter) is reported. The clinical picture of the child is strikingly similar to previous reports of 12p trisomy. The main symptoms of 12p syndrome are defined.     

An improved approach for transformation of plant cells by microinjection: molecular and genetic analysis

A new culture method for the injection of tobacco mesophyll protoplasts has been established. The protoplasts are embedded in a thin layer of alginate and are nourished from the medium in the underlying basislayer. In the alginate layer the protoplasts regenerate to calli at a frequency of up to 80%. Embedded protoplasts can be selected either with 50 mg l⁻¹ kanamycin or 5 mg l⁻¹ paromomycin. Single resistant cells can be recovered from about 10 000 sensitive cells in one alginate layer. Injection of theneo gene (coding for neomycin phosphotransferase II) into protoplast derived single cells in the alginate layer results in kanamycin resistant colonies that can be regenerated to mature plants. These plants express the neomycin phosphotransferase as shown by enzyme activity assay. The integration of the transgene into the plant genome could be proved by Southern hybridization to high molecular weight DNA. With this culture method 100 cells can be injected per hour. Transformation frequencies range from 2 to 20%. In crossing experiments, it was shown that the foreign gene is transmitted to the next generation in a Mendelian fashion.     

Spectroscopic and binding studies of azide to type-2-copper-depleted ascorbate oxidase from zucchini

Summary Binding of azide to type-2-copper-depleted (T2D) zucchini ascorbate oxidase, containing reduced type-3 Cu centers, and met-T2D ascorbate oxidase, containing oxidized type-3 Cu centers, has been studied spectroscopically. In both cases titration with azide in 0.1 M phosphate pH 6.8 produces a broad near-ultraviolet band with maximum at 455 nm (e 2500 M^–1 cm^–1, with respect to the met-T2D enzyme) and shoulder at 390 nm (e 1700 M^–1 cm^–1), that are assigned to(azide)Cu(II) ligand-to-metal charge transfer (LMCT) transitions. This is accompanied by a reduction of absorbance at 330 nm in the met-T2D) enzyme adduct (e –1400 M^–1 cm^–1). A broad circular dichroic band of negative sign between 370–480 nm corresponds to the LMCT absorption band. Analysis of the titration data indicates that one azide ion binds independently to each of the binuclear T3 Cu couples with low affinity (K = 50 M^–1). The ESR signal of the T1 Cu observed in frozen solutions of the T2D enzyme is also perturbed by the addition of azide. The analogies in the azide-binding characteristics between ascorbate oxidase and laccase are discussed.     

Steroid modulation of oxytocin/vasopressin receptors in the uterus

Oxytocin (OT) and V1 vasopressin (VP) receptors are present simultaneously in several tissues, including the uterus. In myometrium these receptors mediate contractility, while in endometrium they mediate the release of other uterotonic substances as endothelin (ET). In rabbit myometrium, estrogens increase, while progesterone blunts neurohypophysial hormone receptors. However, the action of sex steroids on OT and V1 VP receptors differs in terms of the ED₅₀ and maximal effect. Therefore, at parturition, only OT receptors show a dramatic rise, while V1 VP receptors do not change, suggesting a major role for OT in labor. ET is a potent stimulator of uterine activity acting through specific receptors present on myometrial cells. These receptors as well as the endometrial localization of ET are modulated by sex steroids, indicating that ET might represent a paracrine regulator of uterine activity. In humans, OT but not V1 VP receptors increase as pregnancy progresses, confirming the primary relevance of OT in timing delivery.