共查询到20条相似文献,搜索用时 31 毫秒
1.
E. P. Spaziani G. W. Hinsch S. C. Edwards 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1993,163(7):541-545
While the role of eicosanoids in reproduction in vertebrate species has been well established, the role of these fatty acid derivatives in invertebrate species has not been as well characterized. The purpose of this study was to investigate changes in prostaglandins E2 and F2 during vitellogenesis in the crayfish Procambarus paeninsulanus. In homogenates of crayfish ovaries taken at various stages of development, the rate of prostaglandin synthesis and the concentrations of prostaglandins E2 and F2 increased during the final stages of yolk production just prior to ovulation. A gradual increase in prostaglandin E2 amounts was observed throughout the progression of vitellogenesis. The data suggests the possible involvement of prostaglandins in regulatory events associated with vitellogenesis and the induction of ovulation in Procambarus paeninsulanus.Abbreviations EIA
enzyme immunoassay kit
- GIH
gonad inhibiting hormone
- HPLC
high-pressure liquid chromatography
- PGE2
prostaglandin E2
- PGF2
prostaglandin F2
- RIA
radioimmuno assay
- SNK
Student-Newman-Keuls multiple t-test
- TLC
thin-layer chromatography 相似文献
2.
The effect of prostaglandins F2 and E2 on unit activity and sensitivity of somatosensory cortical neurons of rabbits to acetylcholine and noradrenalin was investigated by microiontophoresis. Prostaglandin F2 predominantly inhibited, whereas E2 increased the spike activity of the neurons. F2 usually modified the sensitivity of the neurons to acetylcholine, E2 to noradrenalin. The influence of F2 on the excitatory effects of acetylcholine, and of E2 on the inhibitory effects of noradrenalin as a rule was characterized by weakening of the action of the mediators or a change in the sign of the initial responses. It is suggested that prostaglandins of the F group participate in cholinergic, and those of the E group in adrenergic transmission. The prostaglandins studied evidently exert their action through selective inhibition of the activity of adenylate or guanylate cyclases, leading to a decrease in the synthesis of secondary transmitters, namely cyclic AMP and cyclic GMP.B. K. Anokhin Research Institute of Normal Physiology, Academy of Medical Sciences of the USSR, Moscow. Translated from Neirofiziologiya, Vol. 12, No. 3, pp. 239–245, May–June, 1980. 相似文献
3.
Given the extensive allelic amino acid sequence polymorphism present in the first domain of A, A, and E chains and its profound effects on class II function, the minimal polymorphism in the mouse E chain (and in its human homologue DR) is paradox. Two possible explanations for the lack of polymorphism in E are: (1) the E chain plays such a uniquely critical structural/functional role in antigen presentation, T-cell activation, repertoire selection, and/or pairing with E or other proteins for expression that it cannot vary, and mutations are selected against; (2) the E chain plays a less significant role than the outer domains of other major histocompatibility complex (MHC) proteins in determining the interactions with processed peptides or with T-cell receptor (TCR), so there is no selective pressure to maintain new mutations. To explore this question we compared the ability of transfectants expressing wild type (wt) EE
d and mutant E wt E
d proteins to present peptides and bacterial superantigens to T-cell hybridomas. Mutations at the E amino acid positions 31, 52, and 65&66, to residues that represent allelic alternatives in A chains, significantly reduced activation of peptide-specific T hybridomas, and mutations at 71 sometimes enhanced T-cell stimulation. None of the E mutations reduced, and some enhanced, superantigen stimulation of T-cell hybridomas. These results argue against the hypothesis that E chains are minimally polymorphic because mutations in E are functionally neutral. 相似文献
4.
Masayuki Gotoh Jun-ichi Kitanaka Yoshimi Hirasawa Kaoru Kondo Akemichi Baba 《Neurochemical research》1994,19(6):679-685
Desensitization of prostaglandin (PG) F2 receptor-mediated phosphoinositide (PI) hydrolysis was investigated in cultured rat astrocytes. Prolonged exposure of astrocytes differentiated by dibutyryl cyclic AMP-treatment to PGF2 caused the desensitization of subsequent PGF2-induced PI hydrolysis. The desensitization was time- and PGF2 dose-dependent; maximal decrease in the PI hydrolysis was observed after exposure to 10 M PGF2 for 4 h and the degree of the desensitization was 31.7±2.7% of control. Pretreatment with either PGD2 or PGE2 also induced the desensitization of subsequent PGF2-stimulated PI hydrolysis and conversely pretreatment of PGF2 decreased the PI responses to PGD2 and PGE2. The desensitization prevented by phloretin and was reversible upon removal of the agonist. Protein synthesis inhibitors blocked the recovery of the desensitization. Treatment of the cells with phorbol 12-myristate 13-acetate had no effect on the desensitization. These results suggest that prolonged exposure of the astrocytes to PGF2 caused the desensitization of the receptors. 相似文献
5.
Although protein kinase FA/GSK-3 (an activating factor of ATP.Mg-dependent protein phosphatase) has been established as a cytosolic enzyme in mammalian nonnervous tissues involved in the metabolic regulation, immunological and biochemical studies on tissue and subcellular distributions demonstrate that kinase FA/GSK-3 is in fact a membrane-associated enzyme and most abundantly exists in brain particulate membrane fractions depending on the tissue homogenization conditions. For instance, when brain was homogenized in Polytron without 0.32M sucrose, approximately 40% of the total FA/GSK-3 was found in the cytosol. However, when brain was homogenized in buffer containing 0.32M sucrose and in a glass homogenizer with Teflon pestle, more than 80% of the total FA/GSK-3 was found associated with the particulate membrane fractions. By manipulating these findings, we have developed a simplified procedure for purification of homogeneous kinase FA/GSK-3 in high recovery and in a substantial amount from brain tissue. The data explain why kinase FA/GSK-3 cannot be isolated in a reasonable amount from most mammalian tissues for the past years. The specific pure antibody that can specifically recognize kinase FA/GSK-3 from crude tissue extracts together with the high quantity purification of the enzyme as presented in this report provides an initial key step for studies on the role of kinase FA/GSK-3 in the regulation of brain functions especially in the brain particulate membrane fractions. 相似文献
6.
Molecular and biochemical techniques have been used to explore the reasons behind low E chain expression in the E
+
E
–
I-region recombinant strain, A.TFR5. A.TFR5 (A
f
E
k, ap5), a recombinant between A.CA (A
f
E
f) and A.TL (A
k
E
k), carries the E
k subregion. Previous results have shown that it expresses the E chain, but at reduced levels relative to E
+
E
+
strains. No E chains were detected, which is consistent with the A.TFR5E
gene being derived from the A.CA parent, which carries the null E
f
allele. In this paper, the defect in E-chain expression is explored. Restriction fragment length polymorphism analysis has localized the recombination event in A.TFR5 approximately 30 kb upstream of E, in the region of the large intervening sequence of E. Northern blot analysis of total RNA from A.TFR5 shows normal amounts of the E message, but no E message. Two-dimensional gel analysis of 15 min pulse-labeled A.TFR5, A.CA, and A.TL E immunoprecipitates shows decreased levels of the intracellular E chain in A.TFR5 relative to A.TL. However, analysis of total cell extracts shows normal levels of this protein. A glycoprotein fraction isolated from total cell extracts of 5 h labeled cells contains normal amounts of intracellular E, but decreased amounts of the mature cell-surface protein. These data suggest that in the absence of E, the E chain (1) takes on an altered conformation that is not as efficiently recognized by alloantibodies, and (2) is found in normal levels as the partially glycosylated intracellular precursor, but is not processed and/or transported efficiently to the cell surface. 相似文献
7.
K. Suzuki M. Ishimoto M. Iwanaga F. Kikuchi K. Kitamura 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,90(6):762-766
The inheritance of seed -amylase inhibitor in the common bean and the genetic relationships among the variants and six arcelin variants in the common bean were investigated by crossing between accessions containing different AI and arcelin variants. All seed proteins in parental, F1 and F2 seeds from the crosses were examined by Western-blot analysis. All F1 seeds gave combined AI banding patterns from parents on the blotting membranes. The segregation of F2 seeds for AI variants indicated that the polypeptides of AI variants were inherited as single co-dominant units. Moreover, AI and arcelin behaved as a single block in crosses, indicating a close linkage relationship between the genes controlling these proteins. 相似文献
8.
Summary Two extracellular -glucosidases (EC 3.2.1.20, -D-glucoside glucohydrolase) of the alkalophilic bacterium,Bacillus sp. NCIB 11203, were separated, purified and partially characterised. Resolution of the system into two separate enzymes was achieved by fractionation with (NH4)2SO4 and chromatography on DEAE-Biogel A. The first of these activities, an -glucosidase, hydrolysed p-nitrophenyl--D-glucopyranoside preferentially and had minor activity on isomaltose and isomaltotriose. The second enzyme was a maltase and displayed highest activity on maltose and maltotriose and some activity on p-nitrophenyl--D-glucopyranoside. 相似文献
9.
Mutsumi Miyauchi Takashi Takata Ikuko Ogawa Hiroshi Ito Joji Kobayashi Hirosmasa Nikai Naokuni Ijuhin 《Histochemistry and cell biology》1996,105(1):27-31
To demonstrate the tissue localization of prostaglandin (PG) E2, PGF2 and 6-keto-PGF1 (a stable metabolite of PGI2) various tissues, including decalcified periodontal tissue of 7-week-old male Wistar strain rats, were immunohistochemically examined using a streptavidin-biotin complex method. Besides tissue macrophages and endothelial cells in various tissues, hepatocytes, renal tubular cells, and parietal and chief cells in the gastric mucosa showed a positive reaction for the various PGs examined. PGs were demonstrated in the cytoplasm or in association with the cell membrane. We generally observed no difference between the localization patterns of PGE2-, PGF2-, and 6-keto-PGF1-positive cells in these tissues. However, in the periodontal ligament and alveolar bone, 6-keto-PGF1 was localized in the cytoplasm of osteocytes, osteoblasts, cementocytes, and cementoblasts, while no reaction for PGE2 or PGF2 was revealed in these cells. We demonstrated the immunohistochemical localization of PGs in various rat tissues including decalcified periodontal tissue and discuss the important roles of PGs in the modulation of their normal functions in these tissues. 相似文献
10.
Jun-ichi Kitanaka Takako Hamano Masayuki Gotoh Hitoshi Hashimoto Akemichi Baba 《Neurochemical research》1994,19(12):1545-1550
Effect of tunicamycin, an inhibitor of N-linked glycosylation, on prostaglandin (PG) F2-stimulated phosphoinositide (PI) hydrolysis was examined in cultured rat astrocytes. Pretreatment of cultured astrocytes with tunicamycin (25–250 ng/ml) inhibited subsequent PGF2 (1 M)-stimulated PI hydrolysis in concentration- and time-dependent manners. The inhibition completely recovered after removal of tunicamycin and re-incubation for 12 h. Tunicamycin pretreatment (100 ng/ml for 12 h) significantly blocked [35S]methionine incorporation into cultured astrocytes, but cell viability was not affected under the condition. Inhibitors of processing of N-linked sugar chains such as bromoconduritol, 1-deoxymannojirimycin, and swainsonine had no effect on PI response to PGF2. These observations suggest that PGF2 receptor is N-linked glycosylated. 相似文献
11.
Primary CML was generated in strain combinations 4R anti-2R, R107 anti-3R, 7R anti-9R, and GD anti-R101 — combinations differing only in the chromosomal interval between the I-A subregion and the Ss locus. No CML could be obtained in any of the reciprocal combinations of these strains. This unidirectionality of the CML reaction correlates with the expression or nonexpression of the E molecules encoded by this interval: the reaction occurred in combinations in which the responder strain lacked and the stimulator strain expressed the E molecules in the cell membrane. The CML reaction was positive when tested on LPS-stimulated blast cells but weak on Con A-stimulated blasts and negative on la-negative tumor cells. The reaction could partially be inhibited by monoclonal antibodies to the Ia.m7 determinant presumably carried by the E
chain; it was not inhibited by monoclonal antibodies specific for Ia determinants carried by the A molecule. Cytotoxic lymphocytes specific for a particular combination of E
and E
chains reacted with all cells expressing the particular E
chain, no matter what the origin of the E
chain associated with the E
chain was. Attempts to generate cytotoxic lymphocytes specifically reactive with allotypic determinants on E
chains failed. In F1 hybrids expressing one type of E
chain and two types of E
chain, the single E
chain was found to associate with both chains, producing two types of E molecule. We conclude from these experiments that the CML determinants detected in the strain combinations used are encoded by the same loci as those coding for the serologically detectable la determinants. The CML determinants are carried by the E
chains; the E
chain does not contribute in any way to the specificity of determinant recognition by the cytotoxic lymphocytes. No evidence for allotypic variation of the E
chain as detected by the CML assay could be found in this study. 相似文献
12.
Protein kinase CK2 is ubiquitous in eukaryotes and is known to phosphorylate many protein substrates. The enzyme is normally a heterotetramer composed of catalytic ( and ) and regulatory () subunits. The physiological regulation of the enzyme is still unknown but one of the factors that may play an important role in this regulation is the ratio of the catalytic and regulatory subunits present in cells. The possible existence of free CK2 subunits, not forming part of the holoenzyme, may be relevant to the physiological function of the enzyme in substrate selection or in the interaction of the subunits with other partners. The objective of this work was to study in COS-7 cells the effects of transient expression of CK2 subunits and mutants of the catalytic subunit on the CK2 phosphorylating activity of the extracts of these cells. Using pCEFL vectors that introduce hemaggutinin (HA) or a heptapeptide (AU5) tags in the expressed proteins, COS-7 cells were transfected with and subunits of Xenopus CK2, with the subunit of D. rerio, and with Xl CK2A156, which although inactive can bind tightly to CK2, and with Xl CK2E75E76, which is resistant to heparin and polyanion inhibition. The efficiency of transient transfection was of 10–20% of treated cells.Expression of CK2 or CK2E75E76 in COS-7 cells caused an increase of 5–7-fold of the CK2 activity in the soluble cell extracts. If these catalytic subunits were cotransfected with CK2, the activity increased further to 15–20-fold of the controls. Transfection of CK2 alone also increase the activity of the extracts about 2-fold. Transfection with the inactive CK2A156 yielded extracts with CK2 activities not significantly different from those transfected with the empty vectors. However, cotransfection of CK2 or CK2E75E76 with CK2A156 caused a 60–70% decrease in the CK2 activity as compared to those of cells transfected with only the active CK2 subunits. These results can be interpreted as meaning that CK2A156 is a dominant negative mutant that can compete with the other catalytic subunits for the CK2 subunit. Addition of recombinant CK2 to the assay system of extracts of cells transfected with catalytic subunits causes a very significant increase in their CK2 activity, demonstrating that CK2 subunit is limiting in the extracts and that an excess of free CK2 has been produced in the transfected cells. Transfection of cells with CK2E75E76 results in a CK2 activity of extracts that is 90% resistant to heparin demonstrating that a very large proportion of the CK2 activity is derived from the expression of the exogenous mutant. In both the in vivo and in vitro systems, the sensitivity of CK2E75E76 to heparin increases considerably when it forms part of the holoenzyme CK222. 相似文献
13.
Zippora Gromet-Elhanan 《Journal of bioenergetics and biomembranes》1992,24(5):447-452
F1() complexes containing equimolar ratios of the and subunits have been shown to function as active ATPases, whereas individually isolated and subunits show no real ATPase activity. These results indicate that the single-copy subunits are not required for F1-ATPase activity. The minimal F1()-core complexes exhibit, however, lower rates and some different properties from those of their parent whole F1 or 33 complexes. It is therefore concluded that for obtaining a full spectrum of the characteristic functional properties of an F1-ATPase the presence of the F1- subunit is also required. The implications of these findings on the subunit location of both catalytic and noncatalytic nucleotide binding sites is discussed. 相似文献
14.
Chimeric G proteins, obtained by exchanging their C-terminal portion for that of a G protein from an unrelated class, drive the receptor selectivity to that corresponding to the introduced G protein domain. The 2A-adrenoceptor (2AAR), which yielded an efficacious and weak [35S]GTPS binding response by respectively G o and G i3 protein, was investigated in CHO-K1 cells co-expressing chimeric G proteins for which the six last C-terminal amino acids between G o and G i3 proteins, and reciprocally, were permuted. Activation of the chimeric G o / i3 protein was highly efficient whereas the G i3 / o protein yielded a weak stimulation. These [35S]GTPS binding responses were not different from their parental wild-type G o and G i3 proteins. Similar results were obtained with an 2AAR carrying a facilitating Thr373Lys mutation in a putative G protein interaction domain. These data indicate that the six terminal G o protein amino acids do not constitute a major 2AAR interaction domain for G protein activation. 相似文献
15.
P. Masojć 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1987,73(3):440-444
Summary Fifteen inbred lines of rye, F1 and F2 progenies from crosses between lines were studied using polyacrylamide gel electrophoresis. Conventional genetic analysis of -amylase zymograms showed that the 19 bands detected in the endosperm of germinating caryopses were controlled by three linked structural loci and one independent modifying locus, which influenced the electrophoretic mobility of isozymes. Two codominant alleles were found at the -Amy1, -Amy2 structural loci and the M--Amy modifying locus while the -Amy3 locus had three alleles. Double-banded expression of the -amylase alleles was probably due to the simultaneous presence of modified and unmodified forms of isozymes on the zymogram.This work was supported by Polish Academy of Sciences under project MR-II/7 and was also a part of the author's PhD Thesis 相似文献
16.
The Ca2+ channel 1B subunit is a pore-forming component capable of generating N-type Ca2+ channel activity. Although N-type Ca2+ channel plays a role in a variety of neuronal functions, 1B-deficient mice exhibit normal life span without apparent abnormalities of behavior, histology or plasma norepinephrine level, presumably owing to compensation by some other Ca2+ channel 1 or subunit. In this study, we studied the levels of 1A, 1C, 1D, 1E, 1, 2, 3 and 4 mRNAs in adrenal gland of 1B-deficient mice. The 1A mRNA in homozygous mice was expressed at higher level than in wild or heterozygous mice, but no difference in the expression levels of 1C, 1D, 1E, 1, 2, 3 and 4 was found among wild, heterozygous and homozygous mice. The protein level of 1A in homozygous mice was also expressed at higher level than in wild or heterozygous mice. To examine whether increased expression is induced by cis-regulatory element within 5-upstream region of 1A gene, we examined lacZ expression in 1B-deficient × 1A6.3-lacZ mice (carrying a 6.3-kb 5-upstream fragment of 1A gene fused to E. coli lacZ reporter gene), which express lacZ in medullar chromaffin cells, but not in cortex. The levels of lacZ expression in homozygous 1B-deficient × 1A6.3-lacZ mice were higher than in wild or heterozygous mice. Therefore, a possible explanation of the normal behavior and plasma norepinephrine level of 1B-deficient mice is that compensation by 1A subunit occurs and that 6.3-kb 5-upstream region of 1A gene contains enhancer cis-element(s) for compensation in adrenal medulla chromaffin cells. (Mol Cell Biochem 271: 91–99, 2005) 相似文献
17.
Sa-nga Pootrakul Suwat Sapprapa Prawase Wasi Supa Na-Nakorn Romsai Suwanik 《Human genetics》1975,29(2):121-126
Summary In the Far East two types of -thalassemia genes, namely -thalassemia1 (-thal1) and -thalassemia2 (-thal2) exist. Definite diagnosis of the -thal1 and -thal2 traits is very difficult because their hematological findings are minimally abnormal or normal. This study attempts to characterize the heterozygotes by hemoglobin chain synthesis in reticulocytes from obligatory cases of the -thal1 and -thal2 traits. Twelve parents of babies with hemoglobin Bart's hydrops fetalis (obligatory -thal1 trait) had the mean total radioactivity / ratio of 0.76±SD 0.04, while that of 7 normal controls was 1.06±SD 0.04. The / globin chain ratios of 16 cases, who were either parents or offspring of patients with hemoglobin H disease, were found to segregate into 2 groups, i.e. 0.78±SD 0.03 (10 cases) and 0.92±SD 0.03 (6 cases), probably representing the -thal1 and -thal2 traits respectively. The hematological data of the first group showed definite hypochromic microcytic red cells, similar to thoseof the parents of the hydrops. The second group had significantly higher mean corpuscular hemoglobin than the first group, compatible with -thal2 trait. Our globin chain synthesis study thus appears to be capable of discriminating normal, -thal1 and -thal2 traits.A preliminary report of the results was presented at the XV Congress of the International Society of Haematology, Israel, September, 1974. 相似文献
18.
The α/β Interfaces of α1β1, α3β3, and F1: Domain Motions and Elastic Energy Stored during γ Rotation
ATP synthase (FoF1) consists of F1 (ATP-driven motor) and Fo (H+-driven motor). F1 is a complex of 33 subunits, and is the rotating cam in 33. Thermophilic F1 (TF1) is exceptional in that it can be crystallized as a monomer and an 33 oligomer, and it is sufficiently stable to allow refolding and reassembly of hybrid complexes containing 1, 2, and 3 modified or . The nucleotide-dependent open–close conversion of conformation is an inherent property of an isolated and energy and signals are transferred through / interfaces. The catalytic and noncatalytic interfaces of both mitochondrial F1 (MF1) and TF1 were analyzed by an atom search within the limits of 0.40 nm across the interfaces. Seven (plus thermophilic loop in TF1) contact areas are located at both the catalytic and noncatalytic interfaces on the open form. The number of contact areas on closed increased to 11 and 9, respectively, in the catalytic and noncatalytic interfaces. The interfaces in the barrel domain are immobile. The torsional elastic strain applied through the mobile areas is concentrated in hinge residues and the P-loop in . The notion of elastic energy in FoF1 has been revised. X-ray crystallography of F1 is a static snap shot of one state and the elastic hypotheses are still inconsistent with the structure, dyamics, and kinetics of FoF1. The domain motion and elastic energy in FoF1 will be elucidated by time-resolved crystallography. 相似文献
19.
The expression of polymorphic determinants on I-E molecules is largely dependent on allelic variation in the E
chain. We have previously analyzed the expression of E
k
and E
b
chains in F1 hybrid mice by a combination of techniques, and have shown that functional variation detected by the responsiveness of cloned T-cell lines specific for these molecules correlates well with serological determination of E
expression. In the present study, we have extended our analysis to E
d
expression in F1 hybrid mice. We show that E
d
is relatively poorly expressed in three F1 combinations: H-2
d× H-2
b, H-2
d× H-2
s, and H-2
d× H-2
u. The former two crosses express E
chains from the H-2
dparent only; when recombinant strains carrying E
b
or E
s
and an active E
gene are used, E
d
expression is significantly increased. On the other hand, H-2
umice synthesize E
chains; the poor expression of E
d
chains in this F1 hybrid apparently reflects the strong preferential association of E
u
chains with all E
molecules thus far analyzed. These results confirm that E
chains compete for binding to E
chains and that preferential association of different allelic forms of E
chains with E
chains is a generalized phenomenon. They also illustrate the importance of the rate of biosynthesis of Ia chains for cell-surface expression. 相似文献
20.
Summary Isoelectric focusing (pH 4.0–5.0) of serum 2HS-glycoprotein on polyacrylamide gels has been found to be a useful tool in population genetics and forensic science. Using this method, we isolated three common types, 2HS 1-1, 2HS 2-1 and 2HS 2-2, and showed that 2HS types are determined by two autosomal codominant alleles, 2
HS
1 and 2
HS
2. The method is simple, fast and easy to perform. Results of typing for the two alleles, 2
HS
1 and 2
HS
2, are described for a Japanese population sample (n=1003). 相似文献