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1.
Transforming growth factor (TGF)- isoforms have been implicated in cellular signalling during tooth development and repair, but little is known of their cellular localisation or distribution within the dental tissues in the mature tooth. This study investigated the presence of TGF-1, 2 and 3 isoforms in tissues of sound and carious human molar teeth, to understand better the expression of TGF-s during health and disease. In healthy tissues, odontoblasts, cells of the cell rich layer, pulpal fibroblasts and endothelial cells were stained to varying degrees for all isoforms, with TGF-3 showing the greatest intensity and TGF-1 the weakest intensity. Similar patterns of staining were observed in carious teeth; however, TGF-1 showed significantly increased staining intensity within odontoblasts and pulpal cells of carious teeth (p<0.001). Biochemical analysis showed greater amounts of TGF-1 in tertiary dentine than in primary dentine samples. The expression of TGF-s in odontoblasts and the increased presence of TGF-1 in tertiary dentine suggest that these isoforms may be important in odontoblast behaviour and the modulation of the tissue response to injury.  相似文献   

2.
The mangrove killifish Rivulus marmoratus was reared at 25°±1°C and 17ppt salinity from 0 to 100 days after hatching (DAH), and its early development was described by examining growth and morphometric parameters, meristic characters (vertebral and fin-ray counts), bone-cartilage development, and pigmentation. Growth was isometric for preanal length, head length, snout length, body depth, pectoral-fin length, dorsal-fin length, anal-fin length, and caudal-peduncle depth. Negative allometric growth was observed in eye diameter and gape size. Meristic counts (mean±SD) for vertebrae (34.2±0.4) and dorsal- (8.6±0.5), anal- (11.4±0.5), and caudal-fin rays (30.2±0.8) were complete at 0 DAH (n=5), whereas pectoral-fin rays and pelvic-fin rays were complete by 30 DAH (14.5±0.4, n=5) and 60 DAH (4.2±0.8, n=5). Full ossification of meristic elements proceeded in the following sequence: vertebrae (by 30 DAH), caudal-, dorsal-, and anal-fin rays (by 60 DAH), pectoral-fin rays (between 60 DAH and 100 DAH), and pelvic-fin rays (by 100 DAH). Both morphological characters and meristic counts indicate that this species can be considered to be a juvenile after 9.8mm in standard length (20 DAH).  相似文献   

3.
The action of thyroid hormones on the expression of the mitochondrial ATP synthase -subunit gene (ATPsyn) is controversial. We detected a binding site for the thyroid hormone receptor between-366 and-380 in the human ATPsyn gene by DNase I footprint analysis and band-shift assays. However, expression vectors in which the chloramphenicol acetyl transferase (CAT) reporter gene is driven by the 5 upstream region of ATPsyn gene were unresponsive to T3 when transiently transfected to HepG2 or GH4C1 cells. CAT constructs driven by the rat phosphoenolpyruvate carboxykinase (PEPCK) or the growth hormone (GH) promoters were stimulated several fold by T3 in parallel experiments. It is proposed that the biological effects of thyroid hormones on the ATPsyn expression occur through indirect mechanisms.  相似文献   

4.
Northern-adapted soybean cultivars were screened for their ability to form somatic embryos in vitro in response to exposure to 180 M 2,4-dichlorophenoxyacetic acid in a modified Murashige & Skoog (1962) medium containing B5 (Gamborg et al. 1968) organics and 43.5 mM sucrose. The 20 cultivars formed between 1 and 7 embryos per cotyledon with between 18% and 98% of the cotyledons responding. The response was genotype dependant. Three ancestral lines, 840-7-3, A.K. Harrow and Mandarin were prominent in the genetic background of long-photoperiod adapted lines and showed a high degree of somatic embryogenesis.Abbreviations 2,4-d 2,4 dichlorophenoxyacetic acid - NAA naphthaleneacetic acid  相似文献   

5.
Temperature induction of bacteriophage in Escherichia coli depends on bacterial population density. The lowest rate of viability loss at the temperature threshold results in maximal gene expression of . -Infection causes bacterial cells to lose cell viability and thus decrease temperature induction efficiency. In addition, shifting-up in temperature increases the probability of progeny ; thus, the mortality of bacterial hosts increases and the expression of recombinant proteins by naked significantly decrease.  相似文献   

6.
A possible prebiotic phosphorylation method has been investigated in which formamide served as the reaction medium. Nucleotides and nucleotide derivatives were formed when nucleosides were allowed to react with different orthophosphate, hydrogen phosphate or dihydrogen phosphate salts or with different condensed phosphate salts. The reaction products obtained from the phosphorylation of adenosine were 2, 3 and 5-AMPs, 2, 5 and 3, 5-ADPs, and 2, 3-cyclic AMP. The extent of phosphorylation in formamide exceeded 50% under favorable conditions after 15 days at 70°. The acidic dihydrogen phosphates and condensed hydrogen phosphates proved to be the best phosphorylating agents. The presence of water in the medium decreased the yield of nucleotide derivatives, but some phosphorylation of adenosine was detected using dihydrogen phosphate in formamide containing water. The phosphorylation reactions were also observed for deoxynucleosides. Little decomposition of the nucleosides was detected during the reaction time needed to form nucleotide derivatives. The facility with which phosphorylation takes place in formamide under very mild conditions may justify further studies both of prebiotic phosphorylation and synthetic phosphorylation using this solvent.This work was done while the author was on leave from the Department of Chemistry, University of Colorado, Colorado Springs, Colo, 80907, U.S.A.  相似文献   

7.
Six male volunteers assumed either relaxed or unrelaxed postures, as defined by a Behavioral Relaxation Scale, in seven areas of the body. Electromyographic (EMG) levels in the muscle groups associated with each area were determined for both categories of postures. In all instances, the relaxed postures produced significantly lower EMG levels than the unrelaxed postures. This indicates that the Behavioral Relaxation Scale is a valid behavioral measure of relaxation. Also, it supports other studies which have shown that direct training in emitting relaxed postures is an effective means of achieving relaxation.This study was conducted in partial fulfillment of the M.A. degree by Jerry P. Maurer. Appreciation is expressed to Tz-Yi Jiang, Dr. Robert Lehr, and Jim Rice for their assistance.  相似文献   

8.
Summary. Interferon- (IFN) is a recombinant protein widely used in the therapy of several neoplasms such as myeloma, renal cell carcinoma, epidermoid cervical and head and neck tumours and melanoma. IFN, the first cytokine to be produced by recombinant DNA technology, has emerged as an important regulator of cancer cell growth and differentiation, affecting cellular communication and signal transduction pathways. However, the way by which tumour cell growth is directly suppressed by IFN is not well known. Wide evidence exists on the possibility that cancer cells undergo apoptosis after the exposure to the cytokine. Here we will discuss data obtained by us and others on the post-translational regulation of the expression of proteins involved in the occurrence of apoptotic process such as tissue transglutaminase (tTG) or in the modulation of cell cycle such as the cyclin-dependent kinase inhibitor p27. This new way of regulation of p27 and tTG occurs through the modulation of their proteasome-dependent degradation induced by the cytokine. We will also review the involvement of protein synthesis machinery in the induction of cell growth inhibition by IFN. In details, we will describe the effects of IFN on the expression and activity of the protein kinase dependent from dsRNA (PKR) and on the eukaryotic initiation factor of protein synthesis 5A (eIF-5A) and their correlations with the regulation of cancer cell growth. These data strongly suggest that the antitumour activity of IFN against human tumours could involve still unexplored mechanisms based on post-translational and translational control of the expression of proteins that regulate cell proliferation and apoptosis.  相似文献   

9.
The taxonomic significance of the trunk limbs of the chydoridae (Cladocera)   总被引:1,自引:1,他引:0  
N. N. Smirnov 《Hydrobiologia》1966,27(3-4):337-343
Summary The differences in the structure of the trunk limbs allow to outline three sections of Chydoridae (see table I and fig. 1), coinciding with the sections distinguished according to the structure of the head pores.
Chydoridae (Cladocera)
Chydoridae (. ), , .
  相似文献   

10.
Summary 2-Amino-2-deoxyuridine reacts efficiently with nucleoside 5-phosphorimidazolides in aqueous solution. The dinucleoside monophosphate analogues were obtained in yields exceeding 80% under conditions in which little reaction occurs with the natural nucleosides.In a similar way, the 5-phosphorimidazolide of 2-amino-2-deoxyuridine undergoes self-condensation in aqueous solution to give a complex mixture of oligomers.The phosphoramidate bond in the dinucleoside monophosphate analogues is stable for several days at room temperature and pH 7. The mechanisms of their hydrolysis under acidic and alkaline conditions are described.Abbreviations A adenosine - C cytidine - G guanosine - U uridine - T thymidine - UN 3 2-azido-2-deoxyuridine - UNH 2 2-amino-2-deoxyuridine - ImpA adenosine 5-phosphorimidazolide - ImpU uridine 5-phosphorimidazolide - ImpUN 3 2-azido-2-deoxyuridine 5-phosphorimidazolide - ImpUNH 2 2-amino-2-deoxyuridine 5-phosphorimidazolide - pA adenosine 5-phosphate - pU uridine 5-phosphate - pUN 3 2-azido-2-deoxyuridine 5-phosphate - pUNH 2 2-amino-2-deoxyuridine 5-phosphate - UpA uridylyl-[35]-adenosine - UpU uridylyl-[35]-uridine - UNpA adenylyl-[52]-2-amino-2-deoxy-uridine - UNpU uridylyl-[52]-2-amino-2-deoxyuridine (pUN)n n=2,3,4 [25]-linked oligomers of pUNH 2 poly(A) polyadenylic acid - Im imidazole - MeIm l-methylimidazole  相似文献   

11.
Protoplasts from Chlamydomonas smithii prepared by the action of C. reinhardii gamete autolysine have been studied with respect to cell wall regeneration. Natural protoplasts within sporangia were also investigated for purposes of comparison. In both cases a new cell wall is completed within 2–3 h of the onset of regeneration. The first visible stages of wall regeneration are to be seen after 40–60 min as a fine fringe outside of the plasmalemma. The development of the typical central triplet follows within the next 1 h. Cell wall regeneration is reversibly inhibited by cycloheximide (10g ml-1) and reversibly disturbed by concanavalin A (50 g ml-1). Actinomycin D at concentration over 100g ml-1 also inhibit but the inhibition is irreversible and peculiar membrane effects are observed. Chelators (ethylenediamine tetraacetic acid; ethyleneglycol-bis-aminoethyl ether) and 2-deoxyglucose slightly retard or have no effect on cell wall regeneration.Abbreviations EDTA ethylenediamine tetraacetic acid - EGTA ethyleneglycol-bis(aminoethyl ether) - N,N tetraacetic acid  相似文献   

12.
The cell-surface expression of major histocompatibility (MHC) antigens and the adhesion molecule intercellular adhesion molecule 1 (ICAM-1) is essential for target cell recognition by T lymphocytes. The expression of both classes of molecule is induced by various cytokines, notably interferon (IFN). Since transforming growth factor (TGF) has been recently reported to antagonise HLA-DR induction by IFN we have examined, using a number of murine and human cell lines, the effect of TGF on IFN-induced MHC class I and class II and ICAM-1 expression. All of the cell lines tested expressed elevated class I MHC following IFN treatment. Class II MHC induction was seen on most but not all of the cells, the exceptions being among a panel of human colorectal carcinoma cell lines. A striking difference between cells of different origin was noted in the response to TGF. TGF was found to antagonise IFN-induced class I and class II MHC expression on C3H 10T1/2 murine fibroblasts, early-passage BALB/c mouse embryo fibroblasts, a murine oligodendroglioma cell line, and on MRC5 human fibroblasts and two human glioblastoma cell lines. Class II MHC was much more strongly inhibited (sometimes completely) than class I MHC. TGF also inhibited induction of class I MHC expression by IFN. However, TGF did not inhibit class I or class II MHC induction by IFN in any of the nine colorectal carcinoma cell lines, although two of five of the lines tested were growth-inhibited by TGF. On the other hand, human ICAM-1 induction by IFN was not affected by simultaneous treatment with TGF in any of the cell lines. The down-regulation of IFN-induced MHC antigens by TGF is not, therefore, the result of a general antagonism of IFN. Retinoic acid has recently been reported to induce ICAM-1 expression on human tumour cells. We have confirmed this observation on MRC5, and the two human glioblastoma cell lines, however six colorectal carcinoma cell lines tested did not respond. In contrast to IFN-induced ICAM-1 expression, retinoic-acid-induced ICAM-1 expression was inhibited by TGF on two of the three responsive lines.  相似文献   

13.
Two inbred lines of rye (Secale cereale L), the kernels of which displayed a very low level of -amylase activity (1–3% of the levels generally found in rye), were investigated in comparison with a third normal line. An anti-wheat -amylase immune serum which cross-reacted with the rye enzyme was used in this study.The anti-wheat -amylase immune serum absorbed the -amylase activity in the three lines which were investigated. Comparably small amounts of enzymatic antigen corresponded to the small levels of activity detected in the enzyme-deficient lines. The three inbred lines were equally able to germinate. One of the enzyme-deficient lines was further investigated and neither the level of activity nor the amount of enzymatic antigen were notably changed upon germination.The results indicate that the reduced activity is due neither to the presence of an inhibitor nor to the production of inactive enzymes. Germination can proceed normally without late production of -amylase.  相似文献   

14.
The effects of a series of bisbenzyldiamine analogs have been tested on P388D1 cell line in vitro. Their effects on cell growth, polyamine oxidase (PAO) activity and intracellular polyamine content were determined. The cytotoxicity tests were performed in culture medium supplemented with 100 mol/L aminoguanidine (I), 100 mol/L aminoguanidine and 100 mol/L N,N-bis(2,3-butadienyl)-1,4-butanediamine (MDL 72,527) (II), and finally 100 mol/L aminoguanidine and 200 mol/L D,L-difluoromethylornithine (DFMO) (III). The IC50 values under conditions I and III were similar, suggesting that inhibition of ornithine decarboxylase by DFMO did not affect the biological effect of our derivatives. Spermine and spermidine remained nontoxic in conditions I and III. However in the condition II, the toxicity of all tested compounds (excepted spermidine) was increased, suggesting that the inhibition of cellular PAO increased their toxicity.The enzymatic test of PAO showed that at high doses inhibition of this enzyme by putrescine analogs occurred, while the N-methylated propanediamine derivative increased the enzyme activity; however, these results do not correlate with cytotoxicity tests. When these derivatives were incubated for 48 h with the cells, all of them increased the cell content in putrescine (160%) and spermine (145%) and decreased the spermidine content (75%) without any modification of the total amount of polyamine.The correlation between the cytotoxic results and the intracellular polyamine determination shows that the increase in spermine content along with the inhibition of retroconverting PAO enzyme increases the toxic effect of tested compounds (including spermine), suggesting that spermine toxicity is more important in the absence of intracellular oxidation processes.  相似文献   

15.
Holophosphorylase kinase was digested with Glu-C specific protease; from the peptide mixture calmodulin binding peptides were isolated by affinity chromatography and identified by N-terminal sequence analysis. Two peptides originating from the subunit, having a high tendency to form a positively charged amphiphilic helix and containing tryptophane, were synthesized. Additionally, a homologous region of the subunit and a peptide from the subunit present in a region deleted in the isoform were also selected for synthesis. Binding stoichiometry and affinity were determined by following the enhancement in tryptophane fluorescence occurring upon 1:1 complex formation between these peptides and calmodulin. Finally, Ca2+ binding to calmodulin in presence of peptides was measured. By this way, the peptides 542–566, 547–571, 660–677 and 597–614 have been found to bind specifically to calmodulin.Together with previously predicted and synthesized calmodulin binding peptides four calmodulin binding regions have been characterized on each the and subunits. It can be concluded that endogenous calmodulin can bind to two calmodulin binding regions in as well as to two regions in and . Exogenous calmodulin can bind to two regions in and in . A binding stoichiometry of 0.8mol of calmodulin/ protomer of phosphorylase kinase has been determined by inhibiting the ubiquitination of calmodulin with phosphorylase kinase. Phosphorylase kinase is half maximally activated by 23nM calmodulin which is in the affinity range of calmodulin binding peptides from to calmodulin. Therefore, binding of exogenous calmodulin to activates the enzyme. A model for switching endogenous calmodulin between , and and modulation of ATP binding to as well as Mg2+/ADP binding to by calmodulin is presented.  相似文献   

16.
-Sarcin is a ribosome inactivating protein produced by the mouldAspergillus giganteus. The effect of this protein on eight different tumour cell lines has been studied in the absence of any agent affecting membrane permeability. The protein is cytotoxic for all the tumour cell lines considered. -Sarcin modifies the cell proliferation pattern by inhibiting the protein biosynthesis of the cultured cells. No membrane damage produced by -sarcin has been observed by measuring lactic dehydrogenase leakage. Alteration on the cell mitochondrial activity has not been detected upon treatment with -sarcin. Differences on the extent of the protein binding to the cells have been observed by flow cytometric measurements. The kinetic analysis of the protein biosynthesis inhibition produced by -sarcin reveals an -sarcin concentration-dependent lag phase followed by a first order decrease of the protein synthesis rate. This parameter is dependent on the external -sarcin concentration. A saturable component for the action of -sarcin is also deduced from these experiments. Results are discussed in terms of the protein passage across the cell membrane as the potential rate-limiting step for the action of -sarcin.  相似文献   

17.
Summary We report here a new human -globin gene rearrangement carrying the two normal, 2 and 1, and two hybrid, 1/2, globin genes in the order 5-2-1/2-1/2-1-3. Both the hybrid genes, subtyped with ApaI and RsaI restriction enzymes, were found to be of the uncommon anti 3.7 type II. The hybrid genes were expressed at the biosynthetic level and their interaction with the -thalassaemia IVS 1 nt 1 GA mutation caused thalassaemia intermedia. We also report a case of an -globin gene rearrangement in the twin of one of the -globin gene carriers; the duplicated gene was of the anti 4.2 type and was associated with the absence of RsaI polymorphism. The singular finding of an -anti 3.7 cluster with two identical rare hybrid genes suggests that the reciprocal unequal recombination causing the -globin gene rearrangements could be of the intra-chromosomal rather than the interchromosomal type.  相似文献   

18.
Two-dimensional (2D) gel electrophoresis of immunoprecipitated HLA-DR antigens from eight homozygous typing cells (HTC) expressing the HLA-DRw8 specificity revealed a clustering of polymorphic chain patterns into distinct electrophoretic variants. The variant patterns correlate with three discrete HLA-D clusters that are defined in the mixed leukocyte culture reaction (MLR) using DRw8-positive HTC. These HLA-D clusters have been provisionally designated Dw8.1, detected primarily in Caucasoids, Dw8.2, detected primarily in American Indians, and Dw8.3, detected predominantly in Orientals. All three HLA-Dw8.1 cell lines express a single DR-locus product as defined by immunoprecipitation with a DR-specific monoclonal antibody, P4.1. This DR chain is identical among the Dw8.1 cell lines and different from the DR chains of the Dw8.2 and Dw8.3 cell lines. Two separate Dw8.2 HTC express a shared DR chain that is slightly more basic than the 8.1 DR molecule; interestingly, one of these lines also expresses an additional DR-like chain not found in the other cells. Thus, the two lines defining the Dw8.2 cluster share one distinct class 11 molecule, but differ in another and therefore are not biochemically HLA-identical. Cells from the Dw8.3 cluster are likewise distinct from all other Dw8 clusters. One additional DRw8-positive HTC has been analyzed and found to be distinct from the Dw8.1, 8.2 and 8.3 clusters by both MLR and 2D gels. lmmunoprecipitates using monoclonal antibody 1B5 [anti-DR and anti-DQ(DS)] identify additional polymorphic class II variants among the cell lines tested. These data indicate that HLA-DRw8 is a public serologic specificity present on class II molecules expressed on multiple distinct haplotypes. These haplotypes differ from each other in expression of polymorphic class II molecules encoded by at least two HLA loci. They also differ in HLA-D, even though they all type as HLA-DRw8 homozygous. In Dw8.2, variation in expressed chains is not reflected in variation in HLA-D, indicating that MLR, as well as serologic typing, does not detect the full degree of allelic polymorphism within HLA.  相似文献   

19.
Summary Muskmelon yellowing disease was one of the most serious problems affecting muskmelon crops along the south-east coast of Spain throughout the 1980s. The causal agent of this disease is a virus that we call muskmelon yellows virus (MYV); MYV is transmitted by the greenhouse whitefly Trialeurodes vaporariorum Westwood. It has proven impossible to find sources of resistance to MYV within a wide collection of Spanish muskmelon landraces and exotic varieties. However, Nagata Kin Makuwa and PI 161375, lines of Asiatic origin, show tolerance to this disease. These two lines were studied together with two others (Galia and Piel de Sapo type) that are very susceptible to MYV. The crosses between them (susceptible x tolerant) and the segregant generations derived from these crosses were also investigated. The studies were carried out in two different places and years. The expression of tolerance is influenced by the environment. A parabolic type relationship exists between the average value of percentage of tolerant plants and their variation. This allowed us to quantify the expected response in the segregant generations. The results observed in these generations agreed with a simple genetic control of tolerance. This tolerance, combined with protective measures which delay the infection, can contribute notably to mitigating the effects of MYV.  相似文献   

20.
The present study demonstrates a procedure for the rapid development of a high number of somatic embryos from embryogenic suspension culture. This method might be efficient for mass propagation of Phnix dactylifera L. Embryogenic callus placed in liquid medium with 10–5M ABA yielded an average 72 embryos per 100ml of culture medium within 2months, while those placed on solid medium yielded an average of 33, 20 and 16 embryos per 100ml of culture medium respectively for 10–7, 10–6 and 10–5 M ABA after 4months. The combination of 2,4-DIchlorophenoxyacetic acid (2,4-D) (4.5×10–7M), glutamine (6.7×10–4M), and ABA (10–5M) (L8 liquid medium) showed a beneficial effect on somatic embryos production compared to 2,4-D and glutamine alone, while this combination significantly (p<0.05) increased the accumulation of storage proteins (144 and 138mgg–1 DW respectively for Jihel and Bousthami noir cultivars) in somatic embryos. The somatic embryos which underwent maturation on medium containing only 4.5×10–7M 2,4-D and 10–5M ABA (L6 liquid medium) accumulated more sugars (292 and 265mgg–1 DW respectively for Jihel and Bousthami noir) than those matured on any other liquid medium. Histological studies revealed that somatic embryos (developed in L6 and L8 liquid media) accumulated less reserve compounds (proteins and sugars) than zygotic embryos. The addition of activated charcoal (0.25 and 0.5gl–1) and phytagel® (2.5gl–1) to the germination medium may be useful for enhancing the germination of Phnix dactyliferasomatic embryos.  相似文献   

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