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1.
Soluble receptors for hormones and cytokines have beendescribed. They can serve as natural blockers of theirrespective ligands. The natural soluble interferongamma receptor (sIFNR) has been isolated andcharacterized only in urine. Chromatography of human(hu) plasma from rheumatoid arthritis (RA) patientsand controls on immobilized hu IFN orantibodies against IFN R chainpermitted us to isolate the sIFNR. Thereceptor isolated from one control is a protein witha molecular weight between 60-67 kDa depending on thepresence of reducing agents. We detected asignificantly higher level of plasma sIFNR inpatients with rheumatoid arthritis than in apparentlyhealthy subjects.  相似文献   

2.
Summary Fundamentally, theoretically, there is only one process underlying genetic and cultural evolution: natural selection. Organism fitness-enhancement (adaptive significance) is one of its practical mechanisms; group formation and maintenance is another, often but not always through fitness-enhancement; and need-fulfillment is still another. If Durham can accept that formulation, and switch from organism-thinking to instruction-thinking (Cloak, 1975: 178), he will free himself from two handicaps: First, he can forget his worries about reductionism and determinism (1976a: 100, 101). Under this general theory of natural selection, cultural evolutionis biological evolution, continued by other (nongenetic) means. Second, he will spare himself the appearance of anthropomorphism, mentalism, and wishy-washiness attendant on his discussion of kinds of significance, other than adaptive significance, of cultural behaviors (1976a: 102–106, 115).  相似文献   

3.
Summary -Fructofuranosidase was immobilized by alginate gel at high efficiency (92 %). The extreme long-term continuous reaction (half-life, 275 days) was achieved by the immobilized enzyme using sucrose at high concentration (500 mg ml–1) to produce fructo-olicosaccharides, such as 1-kestose (Fru21Fru21aGlc) and nystose (Fru21Fru21Fru21aGlc).  相似文献   

4.
Summary The total pigment and astaxanthin content ofPhaffia rhodozyma increased with increasing concentrations -pinene up to 500 l -pinene/l. Above this concentration the total pigment and astaxanthin content as well as the biomass production decreased. The addition of 500 l -pinene/l increased the total pigment content from 1652 g/g to 2201 g/g and the astaxanthin content from 1554 g/g to 1883 g/g. A sharp decrease in maximum specific growth rate occurred above 150 l -pinene/l.  相似文献   

5.
On the basis of evidence that several low-molecular-weight substances as well as enzymes are compartmentalised within the socalled soluble phase of the cell, and other considerations, it is argued that DNA may not contain information for certain types of organisation found in living cells. It may be necessary for a cell to possess the non-DNA-controlled organisation for performance of its minimum functions; such organisation would then also serve as a template for its appearance in the daughter cell. The problem of transition from chemical to biological evolution (that is, the formation of the first cell) may be essentially the problem of emergence of such intracellular organisation for which information may not reside in DNA. Two possible mechanisms through which this may have happened are stated.  相似文献   

6.
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   

7.
Residual toxicities of registered and selected experimental pesticides used on citrus against Agistemus industani Gonzalez (Acari: Stigmaeidae) were compared. Pesticides considered highly toxic to A. industani were: abamectin 0.15 EC at 731ml/ha+FC 435-66 petroleum oil at 46.8l/ha, pyridaben 75WP at 469g/ha, ethion 4EC at 7.01l/ha+FC 435-66 petroleum oil at 46.8l/ha, propargite 6.55 EC at 3.51l/ha, chlorfenapyr 2SC at 1.46l/ha applied alone or in combination with FC 435-66 petroleum oil at 46.8l/ha, sulphur 80DF at 16.81kg/ha, dicofol 4EC at 7.01l/ha, fenbutatin oxide 50WP at 2.24kg/ha, benomyl 50WP at 2.24kg/ha, benomyl 50WP at 1.68kg/ha+ferbam 76 GF at 5.60kg/ha, ferbam 76GF at 11.21kg/ha, neem oil 90EC at 46.8l/ha, and copper hydroxide DF (40% metallic copper) at 4.48kg metallic copper/ha+FC 435-66 petroleum oil at 46.8l/ha. Pesticides that were moderately to slightly toxic included: copper sulphate 98% at 4.48kg metallic copper/ha+FC 435-66 petroleum oil at 46.8l/ha, fenbuconazole 2F at 280ml/ha+FC 435-66 petroleum oil at 46.8l/ha, FC 435-66 petroleum oil applied alone at 46.8l/ha or 23.4l/ha, and diflubenzuron 25WP at 1.40kg/ha. Pesticides that were non-toxic included: fenbuconazole 2F at 585ml/ha, malathion 57EC at 5.85l/ha, FC 435-66 petroleum oil at 46.8l/ha, carbaryl 80S at 3.36kg/ha, chlorpyrifos 4EC at 4.68l/ha, and formetanate 92SP at 1.12kg/ha. Understanding the toxic effects of field weathered pesticides against key predacious mite species is important for effective IPM. The results of this study provide a comparison of direct and indirect toxic effects of various pesticides to A. industani under field conditions.  相似文献   

8.
A study was made of the correcting role of autonomous 3" 5" exonucleases (AE) contained in multienzyme DNA polymerase complexes of rat hepatocytes or calf thymocytes. DNA was synthesized on phage X174 amber3 or M13mp2 primer–templates, and used to transfect Escherichia coli spheroplasts. Frequencies were estimated for direct and reverse mutations resulting from mistakes made in the course of in vitro DNA synthesis. The error rate of the hepatocyte complex was estimated at 3·10–6 with equimolar dNTP, and increased tenfold when proteins accounting for 70% of the total 3" 5" exonuclease activity of the complex were removed. The fidelity of DNA synthesis was completely restored in the presence of exogenous AE ( subunit of E. coli DNA polymerase III). Nuclear (Pol n) and cytosolic (Pol c) forms of DNA polymerase were isolated from calf thymocytes. The former was shown to contain an AE (TREX2) absent from the latter. As compared with Pol c, Pol n had a 20-fold higher exo/pol ratio and allowed 4–5 times higher fidelity of DNA synthesis. The error rate of DNA polymerase complexes changed when dNTP were used in nonequimolar amounts.  相似文献   

9.
Summary The relative rates of RNA polymerase biosynthesis in Bacillus subtilis has been examined under steady-state growth conditions. The synthesis of RNA polymerase subunits (, , , ) has been followed by subunit fractionation of immunoprecipitated [3H]-labelled samples on SDS-polyacrylamide gels. The stoichiometries of ::: subunits have been determined from cultures pulse-labelled during steady-state growth. The results suggest that an unassembled pool of the -subunit exists from which the holoenzyme is formed.Upon shift-up from acetate to glycerol containing medium, a rapid rise in the differential rate of core enzyme synthesis was observed, while the rate of synthesis of the -subunit was not stimulated. During shift-down, a concomitant reduction in the rate of synthesis of all subunits occurred for the first 20 min after the shift; thereafter, a rate of synthesis characteristic of the new growth rate was established.As cultures enter sporulation, an immediate reduction in the rate of -subunit synthesis was demonstrated.  相似文献   

10.
Each cryptomonad strain contains only a single spectroscopic type of biliprotein. These biliproteins are isolated as 50000 kDa '2 complexes which carry one bilin on the and three on the subunit. Six different bilins are present on the cryptomonad biliproteins, two of which (phycocyanobilin and phycoerythrobilin) also occur in cyanobacterial and rhodophytan biliproteins, while four are known only in the cryptomonads. The subunit is encoded on the chloroplast genome, whereas the subunits are encoded by a small nuclear multigene family. The subunits of all cryptomonad biliproteins, regardless of spectroscopic type, have highly conserved amino acid sequences, which show > 80% identity with those of rhodophytan phycoerythrin subunits. In contrast, cyanobacteria and red algal chloroplasts each contain several spectroscopically distinct biliproteins organized into macromolecular complexes (phycobilisomes). The data on biliproteins, as well as several other lines of evidence, indicate that the cryptomonad biliprotein antenna system is primitive and antedates that of the cyanobacteria. It is proposed that the gene encoding the cryptomonad biliprotein subunit is the ancestral gene of the gene family encoding cyanobacterial and rhodophytan biliprotein and subunits.Abbreviations Chl chlorophyll - CER chloroplast endoplasmic reticulum - SSU rRNA small subunit ribosomal RNA  相似文献   

11.
T. M. Butt  A. Beckett 《Protoplasma》1984,120(1-2):61-71
Summary A detailed account of the ultrastructure and behaviour of the spindle pole body (SPB) of the entomophthoraceous fungusErynia neoaphidis is presented for the first time.The SPB consists of extranuclear (ENC) and intranuclear (INC) components. The ENC is a saucepan-shaped structure which lies in a pocket of the nuclear envelope. It is composed of a forked, fibrillar handle and a shallow, cylindrical pan. The pan has a wall of two layers, both of which are thickened with a regular periodicity so that they appear to be beaded. It is postulated that the pan is formed from rough endoplasmic reticulum and that it synthesizes the amorphous, electron-dense material coating the ENC.The INC is a saucer-shaped, electron-dense plaque in which the ends of the spindle microtubules terminate. During metaphase, a clear zone separates the INC from the nuclear envelope and persists until telophase. The roles of the amorphous, electron-dense material and the clear zone as well as the method of SPB replication are discussed.  相似文献   

12.
Glycolipids of peripheral leukocytes which had been used for the production of interferon were separated into oligoglycosylceramides, polyglycosylceramides and polyglycosylpeptides (erythroglycan). Neutral oligoglycosylceramides comprised glucosylceramide, galactosylceramide, lactosylceramide, lactotriaosylceramide, globotriaosylceramide andneolactotetraosylceramide. Globotetraosylceramide was not detected. Glycolipids which were more complex thanneolactotetraosylceramide belonged exclusively to theneolacto series of compounds and were essentially unbranched at galactopyranosyl residues. The polyglycosylceramide fraction contained a glycolipid with a probable structure Gal1-4(Fuc1-3) GlcNAc1-3Gal1-4GlcNAc1-3 Gal1-4GlcNAc1-3Gal1-4Glc1-1ceramide. Polyglycosylpeptides were found only in trace amounts and were also unbranched at galactopyranosyl residues. All glycoconjugates studies did not contain significant amounts of carbohydrate structures derived from ABH immunodominant groups.Nomenclature Gal1-4Gal1-4GlcCer Lactotrioasylcermide (LcOse3Cer) - Gal1-4Gal1-4GlcCer globotriaosylceramide, (GbOse4Cer) - GalNAc1-3Gal1-4 Gal1-4GlcCer globoside (globotetraosylceramide, GbOse4Cer) - Gal1-4GlcNAc1-3Gal1-4GlcCer paragloboside (lacto-N-neo tetraosylceramide,nLcOse4Cer)  相似文献   

13.
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   

14.
Summary The gene for -CGTase from an alkalophilic bacterium, Bacillus sp. #1011, was cloned in an Escherichia coli phage D69 and recloned in an E. coli plasmid pBR322 and a B. subtilis plasmid pUB110. An E. coli recombinant plasmid pTUE202 and a B. subtilis plasmid pTUB703 were selected from ten plasmids, because the transformants by each of the two plasmids produced the highest amount of extracellular -CGTase in each strain. The plasmids were stably maintained and expressed in each bacterial strain. A common DNA region of approximately 2.5 kb was defined in the ten plasmids, and the enzymatic activity was lost when a part of the common region was deleted. The major product of hydrolysis from starch by the -CGTases of E. coli [pTUB202] and B. subtilis [pTUB703] was -CD as in the case of the enzyme of the parental Bacillus sp. #1011.Abbreviations -CGTase -cyclodextrin synthetase - -CD -cyclodextrin - -CD -cyclodextrin - -CD -cyclodextrin - [] designates plasmid-carrier state  相似文献   

15.
Summary The temporal muscles of the guinea pig show a sexual differentiation reflected in their histochemical enzyme pattern. Using histochemical methods for mitochondrial (SDH, -GPDH), and glycolytic enzymes (phosphorylase, LDH) it could be shown, that in adult animals the male muscle is a white muscle with marked activity of glycolytic enzymes, the female muscle a red muscle displaying high activity of mitochondrial enzymes. This differential enzyme pattern can be converted by the application of testosterone to the female type during the postnatal development. The male sex hormone thus affects the histochemical enzyme pattern of the muscle, converting the red, female into a white, male muscle in the female guinea pig.  相似文献   

16.
    
A partially purified preparation of 1,3-fucosyltransferase(s) from human milk was used to [14C]fucosylate oligosac-charides containing Gal1-4GlcNAc units. Substitution ofN-acetyllactosamine at position 3 with a -linkedN-acetylglucosamine enhanced the reactivity of the acceptor, whereas similar substitution at position 6 was inhibitory. Thus, the trisaccharide GlcNAcl-6Gal1-4GlcNAc (5), the branched tetrasaccharide GlcNAc1-3(GlcNAc1-6)Gal1-4GlcNAc (11) and the triply branched decasaccharide GlcNAc1-3(GlcNAc1-6)Gall-4GlcNAc1-3[GlcNAc1-3(GlcNAc1-6)Gal1-4GlcNAc1-6]Gal1-4GlcNAc (26) gave remarkably poor yields of 1,3-fucosylated products in comparison to GlcNAc1-3Gal1-4GlcNAc (3). 1,4-Galactosyl derivatives of5 and11, however, gave good yields of 1,3-fucosylated products, but the fucosylation was restricted to the distalN-acetyllactosamine units of Gal1-4GlcNAc1-6Gal1-4GlcNAc (16), Gal1-4GlcNAc1-3(Gal1-4GlcNAc1-6)Gal1-4GlcNAc (18) and also in Gal1-3Gal1-4GlcNAc1-3(Gal1-3Gal1-4GlcNAc1-6)Gal1-4GlcNAc (22). Immobilized wheat germ agglutinin (WGA), possessing high affinity for16 [1], revealed no affinity for the fucosylated derivative Gal1-4(Fuc1-3)GlcNAc1-6Gal1-4GlcNAc (17). The isomeric heptasaccharides Gal1-4(Fuc1-3)GlcNAc1-3(Gal1-4GlcNAc1-6)Gal1-4GlcNAc (19) and Gal1-4GlcNAc1-3[Gal1-4(Fuc1-3)GlcNAc1-6]Gal1-4GlcNAc (20) were readily separated from each other on WGA-agarose, and so were the isomeric nonasaccharides Gal1-3Gal1-4(Fuc1-3)GlcNAc1-3(Gal1-3Gal1-4GlcNAc1-6)Gal1-4GlcNAc (23) and Gal1-3Gal1-4GlcNAc1-3[Gal1-3Gal1-4(Fuc1-3)GlcNAc1-6]Gal1-4GlcNAc (24).  相似文献   

17.
Zusammenfassung In der Meerschweinchenzirbeldrüse lassen sich elektronenmikroskopisch helle und dunkle Pinealzellen sowie einzelne Gliazellen nachweisen. In den bei weitem überwiegenden hellen Pinealzellen zeichnet sich ein Teil der vesicle-crowned rodlets (VCR) durch lokale Auftreibungen aus. Von VCR deutlich abzugrenzen sind die vesicle-crowned balls (VCB). Erstmalig beschrieben wird das Vorkommen von sog. Zylindern, die als Vorstufen von VCB aufgefaßt werden. In den relativ seltenen dunklen Pinealzellen, die sich durch chromatinreiche Kerne und elektronendichtes Zytoplasma auszeichnen, sind Vesikel, VCR, VCB und Zylinder seltener als in hellen Pinealzellen. Die reichlich vorhandenen marklosen Nervenfasern finden sich vor allem in perivasculären Räumen, seltener im Parenchym. Synapsen zwischen Nerven und Pinealzellen wurden nicht beobachtet. In den Zirbeldrüsen trächtiger Meerschweinchen zeichnen sich in der 2. Hälfte der Tragzeit die hellen Pinealzellen durch stärkere Lappung der Kerne, gehäuftes Auftreten von laktiven Zonen, Vermehrung von Mitochondrien, glattem ER, agranulären Vesikeln, VCR, VCB und Zylindern aus. Die dunklen Pinealzellen nehmen während der Tragzeit an Zahl zu. Post partum bilden sich diese Veränderungen innerhalb einer Woche zurück. Längerer Aufenthalt der Tiere in Dunkelheit führt zu einer Aktivierung der hellen Pinealzellen mit auffallender Vermehrung der VCR und zu einer Zunahme der dunklen Zellen. Unter Dauerbelichtung kommt es in den hellen Zellen zu einer Abnahme fast aller Zellorganellen und zu einer starken Vermehrung der VCR, die nach 70 Tagen auch Formveränderungen aufweisen. Nach Reserpinbehandlung beobachtet man eine Verminderung und degenerative Veränderungen der VCR. Es wird diskutiert, daß die VCR als prae- bzw. postsynaptische Strukturen der Erregungsübertragung von Nerven zu Pinealzellen bzw. von Pinealzellen untereinander dienen könnten.
The fine structure of the pineal gland of normal, pregnant and experimentally affected guinea-pigs
Summary By means of electron microscopy light and dark pinealocytes can be distinguished in the guinea-pig pineal gland. Glial cells are rare. In the light pinealocyte. the most frequent cell type, some vesicle-crowned rodlets (VCR) show circumscribed thickenings. From these structures vesicle-crowned balls (VCB) have to be clearly distinguished. Furthermore cylinders occur, which, it is suggested, are precursors of VCB. Dark pinealocytes characterized by chromatin-rich nuclei and electron-dense cytoplasm are rare and contain fewer vesicles, VCR, VCB and cylinders than light pinealocytes. Numerous non-myelinated nerve fibres are situated within perivascular spaces, a few also in the parenchyma. Synapses between nerve fibres and pinealocytes were not observed. In the pineal gland of pregnant guinea-pigs the following changes can be observed in the second half of gestation. The light cells show many nuclear indentations and an increase of active zones, mitochondria, smooth ER, agranular vesicles, VCR, VCB, and cylinders respectively. The dark cells increase in number. After birth these changes reverse to normal within one week. Constant darkness leads to an activation of the light cells accompanied by an increase of the VCR and to an increase in number of the dark cells. Under constant illumination the light cells show a decrease of their organelles and a strong increase of the VCR. After 70 days the VCR also show a change in shape. Following reserpine treatment the VCR decrease in number and show signs of degeneration. It is discussed that the VCR function as pre- or postsynaptic structures and that they are involved either in transmitting impulses from nerve fibres to pinealocytes or from one pinealocyte to the other.
Untersuchung unter Leitung von Univ.-Doz. Dr. L. Vollrath.  相似文献   

18.
Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells.  相似文献   

19.
Plantlets of Bidens pilosus L., considered to be basically symmetrical, can be lateralized (A/B) by being administered a symmetry-breaking signal such as puncturing one of the plant cotyledons. The induced asymmetry remains latent as long as the plants have not been made permissive, i.e. as long as the plant apex is left functioning. When the apex has been removed (plant decapitation), the latent asymmetry is expressed by one of the cotyledonary buds (a/b) statistically beginning to elongate before the other. The interval of time between delivering the symmetry-breaking signal and making the plant permissive is the memorization-time, t. Memorization can be quantified by using a precedence index, q, the values of which range from 0 (no detectable asymmetry with regard to bud growth) to ±1 (bud growth perfectly asymmetric in favour of either bud b or a). Even for memorization times, t, up to 14 d, q-values up to 0.4 (or even larger) are observed. Various experimental characteristics (e.g. light, temperature, presence or absence of the root system) but not the plant age can affect the q-values, at the moment when the treatments are performed, at least in the range of 6 to 25 d. Combining several puncturing treatments either increases or decreases the q-values, depending on the nature of these treatments and the time-intervals, t, between them. Symmetrically removing both cotyledons in the minutes following the puncturing of one of them does not significantly alter the results, which means that the symmetry-breaking message is rapidly transported and memorized within the plant. Non-traumatic asymmetrical treatments (droplets of saline solutions, light-gradients) can also act as symmetry-breaking signals and be memorized. Plants other than Bidens are likely to possess similar memorization ability, although the q-values observed up to now have not been very large.  相似文献   

20.
The ability of four exoglycosidases (-galactosidase, -glucosidase, -glucosidase and invertase) from the termite Macrotermes subhyalinus to catalyse tranglycosylation reactions was tested using lactose, cellobiose, maltose and sucrose as glycosyl donors and 2-phenylethanol as glycosyl acceptor. The experimental conditions were optimized in relation to the time course of the reaction, pH and concentrations of glycosyl donor and acceptor. Whereas the hydrolytic activity was largely predominant over the transferase activity with -galactosidase and -glucosidase, the transglycosylation activity represented 68% with -glucosidase. In addition, as demonstrated by the transglycosylation product formed, the hydrolysis of sucrose was catalysed by -glucosidase and not by invertase. On the basis of this work, -glucosidase from M. subhyalinus appears to be a valuable tool for the preparation of neoglycoconjugates.  相似文献   

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