摘要:

Recent studies from our laboratory have shown that human chorionic gonadotropin (hCG), human luteinizing hormone (hLH), and CG-like proteins fromXanthomonas maltophilia(xCG) andCandida albicans(CaCGLP) induceCandida albicanstransition from blastospores to hyphal forms.Xanthomonas maltophiliaCG-like protein (xCG), hCG, and hLH also bind toCandida albicansblastospores with a high-affinity nM Kd, indicating that these substances can controlCandida albicanspathogenicity. The work reported herein describes the purification of the binding site for these CG-like proteins fromCandida albicans.The purification developed involved alcohol extraction followed by affinity chromatography. The product obtained was a protein of 64–69 kDa, as analyzed by sodium dodecyl sulfate-polyacrylamide electrophoresis (SDS-PAGE), Western blot and Sephadex G-100 column chromatography. This binding site reacted in a Western blot with both125I-hCG and125I-CaCGLP.Purified CaCGLP was able to displace specifically125I-hCG bound toCandida albicansblastospores. Scatchard plot analysis showed that the Kd of this reaction was of high affinity in the nM range, and also indicated the presence of one single binding site. These results lead us to conclude: 1)Candida albicanspossesses a binding site which is able to bind hCG, hLH and CG-like proteins fromXanthomonas maltophiliaandCandida albicans; 2) This binding site is a hydrophobic protein of approximately 64 kDa and; 3) We postulate that CaCGLP is the natural ligand for this binding site and this system is used to controlCandida albicanstransition and, therefore, pathogenicity.

ISSN:0743-5800    

DOI:10.1080/07435809409035852

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

In this study, we characterize fromSaccharomyces cerevisiae: 1) a protein that has immunological similarities to human chorionic gonadotropin (hCG), and 2) a binding site for this hCG-like protein which also binds hCG and human luteinizing hormone (hLH).Saccharomyces cerevisiaechorionic gonadotropin-like protein (ScCGLP) was purified in several steps. This protein when analyzed by SDS-PAGE, under non-denaturing conditions, produced two bands, one at 110-kDa, and another at 57.5-kDa. Under denaturing conditions, only the 57.5-kDa band appeared. This 57.5-kDa band also reacted in a Western blot, using a polyclonal antibody directed against hCG. Purified ScCGLP reacted in the following hCG immunoassays: 1) polyclonal rabbit anti-hCG equilibrium assay, 2) carboxyl-tail hCG equilibrium assay, 3) two equilibrium assays using monoclonal antibodies, and 4) free alpha-chain subunit equilibrium assay using a monoclonal antibody.Characterization of hCG/hLH binding sites inSaccharomyces cerevisiaewas performed, and the ability of the ScCGLP to displace I125-hCG was also shown. Human CG and hLH were able to compete for I125-hCG binding toSaccharomyces cerevisiaeblastospores (Kds of approximately 10-8M), while ScCGLP competed with higher affinity (Kd = 9.41×10-10M).The hCG-like immunoactivity was also present inSaccharomycesgrowth media, as well as in all brands of commercial beer studied.

ISSN:0743-5800    

DOI:10.3109/07435809409035853

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

Alaptide is a drug chemically derived from prolyl-leucyl-glycin amide (PLG) which is effective after oral administration. We studied the effect of long term treatment with alaptide and estradiol-benzoate on serum prolactin, growth reactivity and dopamine DA-2 receptors in the anterior pituitary of male rats.Alaptide reduced adenohypophyseal weight when given alone, but only nonsignificantly reduced growth reactivity of the anterior pituitary (AP) raised by estradiol-benzoate (EB).Alaptide significantly decreased the serum level of prolactin but, on the other hand, significantly increased the binding of3H-spiperone to dopamine DA-2 receptors in AP membrane preparations, without affecting affinity.The administration of alaptide plus EB together resulted in an additional increase of dopamine DA-2 binding sites.We assume that alaptide has a weak dopaminergic activity on the AP of male rats.

ISSN:0743-5800    

DOI:10.3109/07435809409035854

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

Hypothyroidism is associated with muscle weakness and slowed movements Hormone-deficient muscles do show changes in contractile proteins and sacroplasmic calcium pumps, however effects on the components of the neuromuscular junction are less clear. In this study, we examined cholinesterase activity in adult fast-twitch muscle from hypothyroid and control rats. Male Holtzman rats underwent thyroidectomy and their age-matched euthyroid controls were simultaneously subjected to sham operation. Thirty days post-operative, animals were sacrificed for anterior tibialis muscles harvest. Muscle cholinesterase isoform activity was measured and compared between experimental treatment groups. Butryl-cholinesterase activities and peak I and III acetylcholinesterase (AchE) activities were similar in euthyroid and hypothyroid groups. However, hypothyroid muscles exhibited half the peak II AchE isoform (G4) activity, as compared to control muscles. Hypothyroidism specifically affects AchE isoform expression in rodent fast-twitch muscle.

ISSN:0743-5800    

DOI:10.1080/07435809409035855

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

It was the aim of this study to test for a possible effect of the new non ergot dopamine agonist CV 205–502 on plasma growth hormone(GH) concentrations in acromegaly.Plasma growth hormone concentrations decreased by 48.8±8.7 %. The nadir was observed 3 hours after CV 205–502 was administered and GH concentrations remained suppressed throughout the 7 hours of the test period. In contrast GH plasma concentrations in the control group remained stable.We conclude that acute administration of CV 205–502 supresses GH secretion in acromegalic patients and thus could serve as an alternative therapy in acromegaly.10 acromegalic patients received a single oral dose of 150μg CV 205–502 after an overnight fast. As a control group 7 acromegalic patients undertook the same procedure without receiving any drug. Blood samples were drawn hourly up to 7 hours thereafter for determination of GH.

ISSN:0743-5800    

DOI:10.1080/07435809409035856

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

Comparison of binding of125I-porcine FSH to porcine granulosa cells from small and large ovarian follicles indicated that binding is dependent on both time and temperature. At 37 C, binding of ligand is more than four times higher in cells from small follicles than in cells from large follicles within 30 minutes of the start of incubation. Binding to cells from both small and large follicles is more stable for a longer period of time at 20 C than at 37 C. Equilibrium saturation binding analysis of125I-pFSH binding indicated that binding is saturable and of high affinity. Granulosa cells from small and large follicles have similar affinities for125I-pFSH. However, granulosa cells from small follicles have 4.7-times as many FSH receptors as granulosa cells from large follicles. The sensitivity and responsiveness of the adenylyl cyclase system to FSH were assessed by incubating cells from small and large follicles with increasing concentrations of FSH in a defined medium containing isobutylmethylxanthine (1 mM), an inhibitor of phosphodiesterase. Granulosa cells from small follicles are more sensitive to FSH and have a greater cAMP response to FSH than granulosa cells from large follicles. Thus, both active FSH receptors and FSH-responsive adenylyl cyclase activity decline during follicular growth.

ISSN:0743-5800    

DOI:10.1080/07435809409035857

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

The effect of suckling on serum cortisol concentrations was assessed in postpartum lactating women studied during serial breast feeding sessions 1–24 weeks postpartum. The mean±SD serum cortisol concentration at 15 min after the start of nursing, 9.8±3.89μg/dl, was significantly lower, P = 0.001, than prior to the start of nursing, 13.2±5.92μg/dl. The decline in the serum cortisol concentrations in the breast feeding women was not due entirely to the normal metabolism of the hormone or the normal circadian variation in cortisol secretion. These studies complement and expand upon a recent report [3] of a significant decrease in plasma adrenocorticotrophic hormone in breast feeding women studied one week postpartum. The neuroendocrine mechanisms responsible for this effect in women have yet to be defined.

ISSN:0743-5800    

DOI:10.3109/07435809409035858

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor

摘要:

Pineal acid phosphatase (ACP) activity was examined in seven experiments involving young intact or castrated male and female Syrian hamsters. Nine-week old female hamsters had a 3-fold (p<0.001) higher ACP activity in their pineal glands than did males. After three weeks of castration, a significant increase (p<0.001) in ACP activity occurred in castrated male pineal glands. In males, pellets with 5α-dihydrotestosterone (p<0.01) but not testosterone or progesterone suppressed pineal ACP activity. In females, no changes in pineal ACP activity were noted due to the estrous cycle. Pineal ACP activity was not affected by testosterone, dihydrotestosterone or androstenedione pellets in intact females or by testosterone pellets in ovariectomized animals.

ISSN:0743-5800    

DOI:10.1080/07435809409035859

出版商:Taylor&Francis    

年代:1994

数据来源: Taylor