Proteoglycans of animal tissue and their effect on DNA synthesis

A procedure for isolation of proteoglycans (PG) from rat liver and lung has been developed. The effect of PG on DNA and RNA synthesis in fragments of mouse embryo tissue was investigated. PG were shown to inhibit DNA synthesis. This effect was tissue-specific but species-nonspecific. Under the same conditions various glycosaminoglycans (chondroitin sulfates and heparin) had no effect on DNA synthesis. No effect of PG on RNA synthesis was observed. Possible mechanisms of PG effect are discussed.     

Nongenomic effects of progesterone on the contraction of muscle cells from the guinea pig colon

Progesterone (PG) affects muscle cells by genomic mechanisms through nuclear receptors and by nongenomic mechanisms through unidentified pathways. This study aimed to determine the pathways mediating its nongenomic actions. Experiments were performed in dissociated muscle cells from guinea pig colons. Nongenomic actions were defined as those occurring within 10 min of PG exposure. PG blocked the contraction to CCK-8 and NKA (10(-7) M) but did not impair ACh (10(-7) M) and KCl (2.5 x 10(-2) M)-induced contraction. Both CCK-8 and NKA contract muscle cells by releasing calcium from intracellular stores, whereas ACh and KCl can utilize extracellular calcium. PG also blocked the contraction induced by inositol 1,4,5-trisphosphate, thapsigargin, and caffeine, agents that contract muscle cells by releasing calcium from storage sites. The nongenomic actions of PG were transient because they were absent 1 h after the first PG dose, remaining unresponsive after a second PG dose was administered. Furthermore, PG had no effect on the contraction induced by CCK-8 and thapsigargin in muscle cells from animals pretreated with daily intramuscular PG for 4 days. Cytosolic incorporation experiments of [(3)H]PG showed that pretreatment with unlabeled PG significantly reduced the radiolabeled PG incorporation in the cytosol. We conclude that the nongenomic actions of PG on colonic muscle cells transiently blocked calcium release from storage sites, and this response became rapidly desensitized. This effect does not appear to be specific to PG because other steroid hormones such as aldosterone and testosterone can also induce it.     

Effect of phosphatidylglycerol on conformation and micro-environment of tyrosyl residue in photosystem Ⅱ

The structural aspects in the interaction of phosphatidylglycerol (PG) with photosystem II (PSII),mainly the effect of PG on conformation and microenvironment of tyrosine residues of PSII proteins were studied by Fourier transform infrared (FTIR) spectroscopy.It was found that the binding of PG to PSII particle induces changes in the conformation and micropolarity of phenol ring in the tyrosine residues.In other words,the PG effect on the PSII results in blue shift of the stretch vibrational band in the phenol ring from 1620 to 1500 cm-1 with the enhancement of the absorbance intensity.Additionally,a new spectrum of hydrogen bond was also observed.The results imply that the hydrogen-bond formation between the OH group of phenol and one of PG might cause changes in the structures of tyrosine residues in PSII proteins.     

稀土化合物氯化亚鈰对人肺癌细胞PG、人胃癌细胞BGC-823的作用

 以人肺癌细胞 Ｐ Ｇ 和人胃癌细胞 Ｂ Ｇ Ｃ ８２３ 作为研究对象,利用 Ｍ Ｔ Ｔ 测定、３ Ｈ Ｔｄ Ｒ 参入、流式细胞术、软琼脂培养、 Ｎｏｒｔｈｅｒｎ ｂｌｏｔ、 Ｗ ｓｔｅｒｎ ｂｌｏｔ 等实验方法,观察了稀土化合物氯化亚鈰（ Ｃｅ Ｃｌ３）抑癌作用．结果表明, Ｃｅ Ｃｌ３ 浓度为 ００５ ｍ ｍ ｏｌ／ Ｌ,０１ ｍ ｍ ｏｌ／ Ｌ,０５ ｍ ｍ ｏｌ／ Ｌ和 １ ｍ ｍ ｏｌ／ Ｌ可抑制 Ｐ Ｇ 细胞的增殖;浓度为 ０５ ｍ ｍ ｏｌ／ Ｌ和 １ ｍ ｍ ｏｌ／ Ｌ可抑制 Ｐ Ｇ 细胞 Ｄ Ｎ Ａ 的合成,其 Ｇ１ 期细胞比例增加而 Ｓ期细胞比例减少,在软琼脂中的生长能力降低,原癌基因 ｃ ｍ ｙｃ 和 ｃ ｒａｓ 表达降低,ｐ１６ 蛋白质表达降低．而同样浓度的 Ｃｅ Ｃｌ３ 对 Ｂ Ｇ Ｃ ８２３ 细胞和正常细胞 ２ Ｂ Ｓ未见影响．提示：稀土化合物抑制肺癌细胞 Ｐ Ｇ 的增殖以及降低其恶性度的作用机制可能与一些增殖相关的原癌基因的表达和细胞周期的调控有关,其确切的机理还需进一步的研究．     

磷脂酰甘油对光系统Ⅱ放氧活性的影响

The dependence of oxygen evolution in PS Ⅱ from spinach Spinacia oleracea L. on the content of exogenous anionic phosphatidylglycerol (PG) at pH 6.0 was investigated through reconstitution experiment. It was found that there was a steady increase in oxygen evolution. With increasing PG/PS Ⅱ ratio up to a maximum at concentrations ranging from 10-22 mg PG/mg chlorophyll (Chl). Then, further addition of PG resulted in the inhibitions of oxygen evolution. With a PG/PS Ⅱ ratio of 40 mg PG/mg Chl, the oxygen-evolving activity of PS Ⅱ decreased to 40% of the untreated PS Ⅱ. It is suggested that a stimulation of oxygen evolution at a low PG/Chl ratio was resulted from the structural optimization of PS Ⅱ by PG while an inhibitory effect on oxygen evolution at higher values of this ratio was ascribed to the structural changes of extrinsic proteins of PS Ⅱ owing to osmotic pressure.     

Anti-inflammatory effect of proteoglycan and progesterone on human uterine cervical fibroblasts

AimsThe aim of this study was to compare the anti-inflammatory effect of proteoglycan (PG) with that of progesterone (P) in the cultured fibroblasts from human uterine cervix.Main methodsAfter obtaining informed consent, the cervix was collected from normal women undergoing total hysterectomy. The cervix was cultured until fibroblasts proliferated and had grown to confluence, then, the fibroblasts were stimulated by lipopolysaccharide (LPS) with or without PG, P and a combination of both; they were cultured for 24–48 h. The anti-inflammatory effects of PG and P were evaluated by the suppression of IL-6 or IL-8 secretion. The expression of the IL-6 or IL-8 gene and the expression of their protein were determined by real-time PCR, and ELISA, respectively. Activation of Toll-like receptor (TLR) 4 was evaluated by Western blotting.Key findingsLPS markedly enhanced gene and protein expression of IL-6 and IL-8 in human uterine cervical fibroblasts. The up-regulation of the IL-6 or IL-8 gene and protein expression by LPS was significantly suppressed with PG, P and a combination of both. Western blotting revealed that combination of PG and P showed more potent inhibition on LPS-stimulated TLR4 induction than that seen by each.SignificanceThis study showed that both PG and P have an inhibitory effect on LPS-induced inflammation. This anti-inflammatory effect of PG and P was augmented by co-administration of both, suggesting for the first time that PG has an anti-inflammatory effect on human uterine cervical fibroblasts.     

Inhibitory and stimulating effects of various types and series of prostaglandins on in vitro biosynthesis of proteochondroitin-4,6-sulfate and protein and anaerobic glycolysis in calf rib cartilage

The effect of various types of prostaglandins (PGs) have been studied in a semi-in-vitro system with cartilage slices of calf ribs. 0.1 mmol/1 PG B1, D2, E1, E2, F1 alpha, F2 alpha inhibit biosynthesis of Ch-4,6-S protein to a higher extent than 10 mumol/l; 1 and 2 series PG E and F (but not B) inhibit similarly, PG A2 inhibits twice as much. With biosynthesis of total protein 2-series PG A, B, E, F act more inhibitorily than 1-series PG. 10 mumol/l PG A2, E1, E2 produce cAMP-like effects, e.g. acceleration of biosynthesis of Ch-4,6-S protein and total protein as well as of anaerobic glycolysis; PG F2 alpha stimulates the first two anabolic processes, PG B1 only the second one. PG A1 stimulates Ch-4,6-S protein biosynthesis and anaerobic glycolysis, a cGMP-like effect. 20 mumol/l diBu-cAMP or cAMP (together with 0.1 mmol/l theophylline) produce stimulating and inhibitory effects on these three anabolic processes; both compounds produce additively positive or additively negative effects in connection with the inhibitory PG effects on these three anabolic processes.     

Hydrocarbon chain packing and the effect of ethanol on the thermotropic phase behavior of mixed-chain phosphatidylglycerols

Previous studies in this laboratory have delineated the relationship between the acyl chain asymmetry of mixed-chain phosphatidylcholines and the effect of ethanol concentration ([EtOH]) on their melting behavior (Li et al., Biophys J., 70 (1996) 2784-2794). This present investigation extends these findings to another phospholipid family by using high-resolution differential scanning calorimetry (DSC) to characterize the effect of ethanol concentration on the main phase transition temperature (Tm) of five molecular species of mixed-chain phosphatidylglycerol (PG). For C(14):C(18)PG, C(15):C(17)PG, C(16):C(16)PG, and C(17):C(15)PG, a biphasic profile in the Tm versus [EtOH] plot was observed, and the minimum in the plot for each PG occurred at 33, 15, 19, and 36 mg/ml, respectively. This biphasic behavior is typical of phospholipids whose acyl chain asymmetry is fairly small. For C(18):C(14)PG, only a linear decrease in the Tm was observed as a function of ethanol concentration; this effect is characteristic of highly asymmetric phospholipids. Our DSC results obtained with mixed-chain PG in the presence of ethanol demonstrate that the acyl chain asymmetry of the five lipids studied can be ranked as follows: C(15):C(17)PG相似文献   

Effect of phosphatidylglycerol on conformation and micro-environment of tyrosyl residue in photosystem II

The structural aspects in the interaction of phosphatidylglycerol (PG) with photosystem II (PSIl), mainly the effect of PQ on conformation and microenvironment of tyrosine residues of PSIl proteins were studied by Fourier transform infrared (FTIR) spectroscopy. It was found that the binding of PG to PSIl particle induces changes in the conformation and micropolarity of phenol ring in the tyrosine residues. In other words, the PG effect on the PSIl results in blue shift of the stretch vibrational band in the phenol ring from 1620 to 1500 cm-1 with the enhancement of the absorb-ance intensity. Additionally, a new spectrum of hydrogen bond was also observed. The results imply that the hydrogen-bond formation between the OH group of phenol and one of PG might cause changes in the structures of tyrosine residues in PSIl proteins.     

Polygalacturonase production by Kluyveromyces marxianus: effect of medium composition

A strain of Kluyveromyces marxianus (CCT 3172), isolated from a cocoa fermentation in Brazil, secreted an endopolygalacturonase (PG) when grown under self-induced anaerobic conditions; neither polymethylesterase nor pectate lyase appeared in culture filtrates. Replacing glucose in the medium with sucrose had no effect on PG secretion or ethanol production. Growth in fructose-containing medium retarded secretion of PG and ethanol, but had no effect on growth. Growth and ethanol production in media containing galactose resembled those in fructose-containing medium, although PG secretion was lowered. Growth and PG secretion were considerably retarded in xylose-containing medium, and were similarly affected in media containing different concentrations of glucose. Varying the concentration of ammonium sulphate in media had no effect on growth or PG secretion.     

The effect of feeding propylene glycol to dairy cows during the early postpartum period on follicular dynamics and on metabolic parameters related to fertility

Postpartum dairy cows (n=35) were used to determine the effects of feeding propylene glycol (PG) on metabolic variables related to ovarian function and on oocyte developmental competence. Starting on Day 7 postpartum, each animal received an oral dose (500 ml) of either PG or water once daily. Blood samples were collected on Days 5, 15, 25 and 35 pp to measure insulin, non-esterified fatty acids (NEFAs), beta-hydroxybutyrate (BHB) and glucose concentrations. Oocytes were recovered by ultrasound guided follicular aspiration starting on approximately Day 30 postpartum and submitted to in vitro fertilization. Ovarian follicular activity was examined daily by ultrasonography from Day 7 until ovulation or Days 35-40 postpartum. Animals receiving PG had elevated insulin concentrations over the subsequent 90 min following dosing (P<0.05) compared to control animals. Glucose concentrations followed a similar pattern. Irrespective of treatment, concentrations of NEFA declined significantly from Days 15 to 35 postpartum. Administration of PG resulted in a decrease in NEFA (P<0.001) and BHB (P<0.001) over the subsequent 90 min compared to control animals. Treatment with PG had no effect on follicular dynamics, mean days to emergence of the first cohort of follicles postpartum, or days to dominance and duration of dominance for any follicular wave recorded postpartum. There was also no difference in mean days to first ovulation or in size of the preovulatory follicle between treatments. Oocyte quality as measured by blastocyst development after IVF was not affected by treatment. These results suggest that administration of PG has the ability to positively alter the systemic concentrations of a number of metabolic variables which have been related to fertility. However, we did not observe an effect of PG treatment on follicular dynamics or the length of the postpartum interval. An effect on oocyte developmental competence remains to be proven.     

Effect of indomethacin on aloin and 1,8 dioxianthraquinone-induced production of prostaglandins in rat isolated colon

The effect of aloin and 1,8 dioxyanthraquinone on the release of prostaglandin-like material (PG) from rat isolated colon has been investigated. Orally administered aloin and 1,8 dioxyanthraquinone stimulates PG production by subsequently isolated segments of colon. Indomethacin was able to prevent this increased production of PG. These results suggest that the laxative properties of aloin and 1,8 dioxyanthraquinone may depend, at least in part, on increased prostaglandin synthesis by the intestinal tissue.     

Effects of copper and zinc on proteoglycan metabolism in articular cartilage

Co-Cultures of porcine articular cartilage and synovium or synovial conditioned medium were used as an in vitro model to mimic inflammatory events at the cartilage/synovial junction in degenerative joint disease. This model provides a useful tool to assess the anti-inflammatory and antiarthritic properties of pharmacological agents. In this study the effects of copper and zinc on (i) PG synthesis by cartilage and (ii) synovial-induced PG depletion have been investigated. Copper sulphate at a concentration of 0.01 mM did not stimulate PG synthesis significantly in cultured cartilage explants but completely abrogated the inhibitory effects of synovial tissue in co-culture experiments. This finding was supported by the histological demonstration of copper-dependent reversal of the PG depletion in cartilage exposed to synovial conditioned medium. Zinc sulphate at 0.01 mM had no effect on PG synthesis and was unable to protect cartilage against synovialinduced PG depletion. These results reveal possible mechanisms by which copper exerts its anti-inflammatory and anti-arthritic actions.     

The effects of platelet-activating factor on the output of prostaglandins from the guinea-pig uterus

Platelet-activating factor (PAF) significantly increased the output of prostaglandin (PG) F2 alpha from the guinea-pig uterus during the mid-cycle phase (Days 6-10), but only had a small, non-significant stimulatory effect on the outputs of PGE2 and 6-keto-PGF1 alpha. PAF significantly increased the outputs of PGF2 alpha, PGE2 and 6-keto-PGF1 alpha from the guinea-pig uterus during the later phase of the cycle (Days 15-17). Lack of extracellular calcium did not affect the stimulatory effect of PAF on uterine PG output. However, TMB-8 (an intracellular calcium antagonist) prevented the increases in uterine PG output produced by PAF at both phases of the cycle. These results suggest that the stimulatory effect of PAF on uterine PG output in the guinea-pig is dependent upon the mobilization of intracellular calcium but is not dependent upon the uptake of extracellular calcium. Also, the weak stimulatory effect of PAF on PGE2 output from the uterus during the mid-cycle phase indicates that, if PAF is involved in implantation in guinea-pigs, it probably does not act via PGE2. Also, the lack of an inhibitory effect of PAF on uterine PGF2 alpha synthesis and release suggests that PAF is not the anti-luteolytic factor produced by the guinea-pig conceptus during early pregnancy.     

Effects of arachidonic,linoleic, linolenic and oleic acid on experimental arrhythmias in cats,rabbits and guinea-pigs

Antiarrhythmic effects of the Prostaglandin (PG) precursors arachidonic and Linoleic acid were demonstrated on three models of experimental arrhythmias, whereas the fatty acids linolenic and oleic acid proved to be ineffective in these models. In ouabain-induced arrhythmias infusions of arachidonic acid (1,0 mg/kg/min) caused a strong antiarrhythmic effect in 80 percent of the animals. On the same model linoleic acid showed a maximum effect in 40 percent of the animals. BaCl₂-induced arrhythmias were abolished by arachidonic and linoleic acid in 60 percent and 66 percent of the rabbits, respectively. Pretreatment by indomethacin reduced the antiarrhythmic effect of linoleic acid from 40 percent to 9 percent on ouabain-induced arrhythmias in cats. The results suggest a participation of PG synthesis in the antiarrhythmic effect of PG precursors.     

A mixed model for the effects of single gene,polygenes and their interaction on quantitative traits

Summary A model for the effects of single gene (SG), polygenes (PG) and their interaction on quantitative traits was developed. It is a mixed model where the SG is a fixed effect and the PG is a random effect. A two-way factorial experiment, in which the SG and the PG are the main effects, is proposed. The experimental material is comprised of F₃ families derived from F₂ plants heterozygous for the SG. For this experiment an ANOVA table with expected mean square is proposed, which facilitates estimation of the components of the model and testing of their significance. A detailed method for the interpretation of results from such an experiment is proposed, with emphasis on the analysis of the SG × PG interaction. Theoretical and applied aspects of SG × PG interaction is discussed.This paper is part of a Ph.D. Thesis of the senior author to be submitted to the Hebrew University of Jerusalem     

Effect of repeated flushing and a prostaglandin analogue on the estrous cycle of pony mares

An experiment was conducted to test the effect of repeated transcervical (non-surgical) uterine flushing and a prostaglandin analogue (PG) on the estrous cycle of pony mares. Uteri in group A were trancervically flushed for embryos 7 to 9 days post ovulation. In addition, group B mares were given 5 ml of PG by intramuscular injection on the day of flushing. Group C served as controls and were not flushed or given PG but were allowed to cycle normally. All mares (except controls) were bred A.I. every other day during estrus. There was no effect on embryo recovery rate from repeated flushing or PG administration. The number of days in estrus was greater for groups A and B than for group C (P<0.05). Length of diestrus was longer for group C than for the other two groups. The total estrous cycle length was similar for all three groups (P>0.05).     

Prostaglandin production in cultured gastric mucosal cells: role of cAMP on its modulation

The effect of cAMP on prostaglandin production may depend on cell types. To clarify the relationship between PG and cAMP, we examined arachidonate's effects on PG synthesis and intracellular cAMP accumulation in monolayers of rat gastric mucosal cells. These cells produced PGE2, PGI2 and thromboxaneA2 (TXA2) in amounts of 316 +/- 18, 100 +/- 7 and 30 +/- 5 pg per 10(5) cells in 10 min, respectively, in response to 10 microM arachidonic acid (AA). The production of these PG, however, leveled off subsequently. Cells initially exposed to AA responded poorly to a subsequent stimulation by AA. AA simultaneously stimulated intracellular cAMP accumulation; this stimulatory effect on cAMP production was abolished by the pretreatment with indomethacin. Nevertheless, the pretreatments with dibutyryl cAMP (0.1-5 mM) did not alter the amount of subsequent AA-induced PGE2 production. Furthermore, the preincubation with 1mM isobutyl methyl xanthine also failed to affect PGE2 synthesis, while it increased intracellular cAMP accumulation. Our studies suggest AA stimulates intracellular cAMP formation in cultured gastric mucosal cells, linked with conversion of AA to cyclooxygenase metabolites, AA-induced PG production is limited in these cells, and it seems, however, unlikely that intracellular cAMP modulates AA metabolism to PG.