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1.
The purpose of the paper was to study the morphological effects of retinoids on non-transformed cells such as thyrocytes. The formation of follicles was studied in primary cultures of porcine thyrocytes by adding retinol and thyroid stimulating hormone (TSH) to cells grown in the absence of TSH to form monolayers. The proliferation and apoptosis of thyrocytes were studied in cells both grown adherent to plastic surfaces and in suspension. Standard medium with traces of retinol and the same medium without retinol were used. Retinol alone was added to thyrocytes grown in the absence of TSH (TSH culture) or both retinol and TSH were added to cultures after stimulation with TSH (TSH culture). The concentration was varied from 0 to 80M for retinol and from 0 to 13M for retinoic acid. At a concentration of 13M, the effect of retinol was similar to that of retinoic acid. At concentrations higher than 40M, retinol reduced the formation of thyroglobulin-immunoreactive follicles, whereas up to 13M retinoic acid had no obvious influence on follicle formation. The retinoids induced apoptosis under all experimental conditions. In contrast, a significant decrease in proliferation and in the formation of thyroglobulin-immunoreactive follicles was observed only in adherent cells cultured in customary medium. The decrease in functional follicles after treatment with retinol suggests a de-differentiating effect of retinoids on normal thyrocytes and is in contrast with the differentiating effect of retinoids observed in cancer cells. 相似文献
2.
Summary The oxidized form of the mercuric ion binding protein MerP has been studied by two-dimensional NMR. MerP, which is a periplasmic water-soluble protein with 72 amino acids, is involved in the detoxification of mercuric ions in bacteria with resistance against mercury. The mercuric ions in the periplasmic space are first scavenged by the MerP protein, then transported into the cytoplasm by the membrane-bound transport protein MerT, and finally reduced to elementary (nontoxic) mercury by the enzyme mercuric reductase. In this work, the 1H NMR spectrum of oxidized MerP (closed disulfide bridge) has been assigned by using homonuclear 2D NMR techniques. The secondary structure and global fold have been inferred from the nuclear Overhauser effect (NOE) data. The secondary structure comprises four -strands and two -helices, in the order 112324. The protein folds into an antiparallel -sheet, 2314, with the two antiparallel helices on one side of the sheet. The folding topology is similar to that of acylphosphatase, the activation domain of porcine pancreatic procarboxypeptidase B, the DNA-binding domain of bovine papillomavirus-1 E2 and the RNA-binding domains of the U1 snRNP A and hnRNP C proteins. However, there is no structural similarity between MerP and other bacterial periplasmic binding proteins. 相似文献
3.
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
4.
Gabriele Möller Folkert Reck Hans Paulsen Kanwal J. Kaur Mohan Sarkar Harry Schachter Inka Brockhausen 《Glycoconjugate journal》1992,9(4):180-190
UDP-GlcNAc: Man3R 2-N-acetylglucosaminyltransferase I (GlcNAc-T I; EC 2.4.1.101) is the key enzyme in the synthesis of complex and hybrid N-glycans. Rat liver GlcNAc-T I has been purified more than 25,000-fold (M
r 42,000). TheV
max for the pure enzyme with [Man6(Man3)Man6](Man3)Man4GlcNAc4GlcNAc-Asn as substrate was 4.6 µmol min–1 mg–1. Structural analysis of the enzyme product by proton nuclear magnetic resonance spectroscopy proved that the enzyme adds anN-acetylglucosamine (GlcNAc) residue in 1–2 linkage to the Man3Man-terminus of the substrate. Several derivatives of Man6(Man3)Man-R, a substrate for the enzyme, were synthesized and tested as substrates and inhibitors. An unsubstituted equatorial 4-hydroxyl and an axial 2-hydroxyl on the -linked mannose of Man6(Man3)Man-R are essential for GlcNAc-T I activity. Elimination of the 4-hydroxyl of the 3-linked mannose (Man) of the substrate increases theK
M 20-fold. Modifications on the 6-linked mannose or on the core structure affect mainly theK
M and to a lesser degree theV
max, e.g., substitutions of the Man6 residue at the 2-position by GlcNAc or at the 3- and 6-positions by mannose lower theK
M, whereas various other substitutions at the 3-position increase theK
M slightly. Man6(Man3)4-O-methyl-Man4GlcNAc was found to be a weak inhibitor of GlcNAc-T I.Abbreviations BSA
Bovine serum albumin
- Bn
benzyl
- Fuc, F
l-fucose
- Gal, G
d-galactose
- GalNAc, GA
N-acetyl-d-galactosamine
- Glc
d-glucose
- GlcNAc, Gn
N-acetyl-d-glucosamine
- HPLC
high performance liquid chromatography
- Man, M
d-mannose
- mco
8-methoxycarbonyl-octyl, (CH2)8 COOOCH3
- Me
methyl
- MES
2-(N-morpholino)ethanesulfonate
- NMR
nuclear magnetic resonance
- PMSF
phenylmethylsulfonylfluoride
- pnp
p-nitrophenyl
- SDS
sodium dodecyl sulfate
- T
transferase
- Tal
d-talose
- Xyl
d-xylose;
- {0, 2 + F}
Man6 (GlcNAc2Man3) Man4GlcNAc4 (Fuc6) GlcNAc
- {2, 2}
GlcNAc2Man6 (GlcNAc2Man3) Man4GlcNAc4GlcNAc; M5-glycopeptide, Man6 (Man3) Man6 (Man3) Man4 GlcNAc4GlcNAc-Asn
Enzymes: GlcNAc-transferase I, EC 2.4.1.101; GlcNAc-transferase II, EC 2.4.1.143; GlcNAc-transferase III, EC 2.4.1.144; GlcNAc-transferase IV, EC 2.4.1.145; GlcNAc-transferase V, UDP-GlcNAc: GlcNAc2 Man6-R (GlcNAc to Man) 6-GlcNAc-transferase; GlcNAc-transferase VI, UDP-GlcNAc: GlcNAc6(GlcNAc2) Man6-R (GlcNAc to Man) 4-GlcNAc-transferase; Core 1 3-Gal-transferase, EC 2.4.1.122; 4-Gal-transferase, EC 2.4.1.38; 3-Gal-transferase, UDP-Gal: GlcNAc-R 3-Gal-transferase; blood group i 3-GlcNAc-transferase, EC 2.4.1.149; blood group I 6-GlcNAc-transferase, UDP-GlcNAc: GlcNAc3Gal-R (GlcNAc to Gal) 6-GlcNAc-transferase. 相似文献
5.
Ray I. Chauhan A. Wisniewski H. M. Wegiel J. Kim K. S. Chauhan V. P. S. 《Neurochemical research》1998,23(10):1277-1282
Amyloid beta-protein (A), in its soluble form, is known to bind several circulatory proteins such as apolipoprotein (apo) E, apo J and transthyretin. However, the binding of A to intracellular proteins has not been studied. We have developed an overlay assay to study A binding to intracellular brain proteins. The supernatants from both rat and human brains were found to contain several proteins that bind to A 1–40 and A 1–42. No major difference was observed in the A binding-proteins from brain supernatants of patients with Alzheimer's disease and normal age-matched controls. Binding studies using shorter amyloid beta-peptides and competitive overlay assays showed that the binding site of A to brain proteins resides between 12–28 amino acid sequence of A. The presence of several intracellular A-binding (AB) proteins suggests that these proteins may either protect A from its fibrillization or alternatively promote A polymerization. Identification of these proteins and their binding affinities for A are needed to assess their potential role in the pathogenesis of Alzheimer's disease. 相似文献
6.
Feulgen and silver-stained karyotypes and meiosis of two triploid viviparous onion forms (Allium cepa var.viviparum), the Croatian Ljutika and the Indian Pran, were comparatively analyzed. The results of chromosome measurements show that Ljutika and Pran are karyologically not identical, although significant similarities were found in the morphology of their chromosomes. Five geographically distant clones of Ljutika showed good agreement in the number and gross morphology of the chromosomes and in the number and position of NORs and interphase nucleoli. Heterotrivalents were predominant in meiosis of Ljutika but a relatively high frequency of higher multivalents together with univalents and bivalents were also observed. The relationship between Ljutika and Pran and their possible origin are discussed. 相似文献
7.
Reinhart Munk 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1968,58(4):423-428
Zusammenfassung Der Verlauf des Nahrungsflusses im Darmtrakt der Kleinzikade Euscelidius variegatus wird nach Verfütterung von farbstoffhaltiger Nährlösung ermittelt. Es wird der Beweis erbracht, daß die aufgenommene Nahrungsmenge in der Filterkammer geteilt wird und die beiden Anteile den Darmtrakt auf zwei verschiedenen Wegen in Richtung Rektalblase passieren. Ein Anteil der aufgenommenen Nährlösung wird über einen Kurzschlußweg in der Filterkammer sowohl über den Filterkammerdarm als auch über die Kryptonephridien direkt in den Enddarm gepumpt, während die in der Magentasche der Filterkammer verbleibenden Nahrungsanteile über einen langen Verdauungsweg zum After gelangen. Hierbei wird der Magentascheninhalt in den Magen gedrückt. Von dort aus passiert er den Mitteldarm und erreicht über den Enddarm den After. Der Kurzschlußweg und der Verdauungsweg können gleichzeitig benutzt werden. Der Kurzschlußweg wird von der Nahrung jedoch in viel kürzerer Zeit durchströmt als der längere Verdauungsweg.
The directions of the flow of food in the alimentary trad of the leafhopper Euscelidius variegatus KBM. (Jassidae)
Summary The leafhopper Euscelidius variegatus is fed with synthetic food, coloured with 1% Azorubin-S. Its flow in the alimentary tract has been studied. It has been found that the sucked-in food is divided into two parts in the filter chamber, each taking different way in the alimentary tract for its flow. One part of the food is pumped into the hindgut via the short circuit way going through the filter chamber once over the Filterkammerdarm and also over the kryptonephries. That part of the food, which remains in the pocket of the filter chamber takes the long digestion way to the anus over stomach, midgut and hindgut. Both the ways could be used at the same time. But the food takes much shorter time for its passage through the short circuit way as compared to the time needed for the long digestion way.相似文献
8.
The activity of UDP-Gal: LacCer galactosyltransferase in human placenta was studied by using crude homogenate and Triton CF-54 extract as the source of enzyme. Transfer of galactose to lactosylceramide was optimal in the presence of 0.1% Triton CF-54 and Mn2+ at pH 6.3, and the reaction product was susceptible to -galactosidase.Abbreviations LacCer
lactosylceramide (Gal1-4Glc1-1Cer)
- Gb3
globotriaosylceramide (Gal1-4Gal1-4Glc1-1Cer)
- Gb4
globoside (GalNAc1-3Gal1-4Gal1-4Glc1-1Cer)
- TLC
thin-layer chromatography
- GC/MS
gas chromatography/mass spectrometry
- NMR
nuclear magnetic resonance
- EDTA
ethylenediamine tetraacetic acid
- CHAPS
3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate 相似文献
9.
Observations on morphology, sterility and cytology of some interchangetrisomics obtained from the progeny of radiation induced interchangeheterozygotes in a 6-rowed barley (Hordeum vulgare L.) var. K12 are described. The different interchange trisomics show distinct phenotypic expression and have been classified as bushy, slender, robust, semi-erect and pseudonormal on the basis of their gross morphology, leaf characteristics, awn and spike lengths. All interchange trisomics show pollen and ovule sterility which varies between plants. Meiotic behaviour is described. The five different interchange trisomics appear to have different extra chromosomes. 相似文献
10.
H. J. Sips H. A. de Wit-Verbeek J. de Wit A. Westerveld H. Galjaard 《Human genetics》1985,69(4):340-344
Summary A series of man-Chinese hamster and man-mouse somatic cell hybrids was investigated to study the localization of the genes coding for the human lysosomal enzyme -galactosidase (EC 3.2.1.23) and for its protective protein. Using a monoclonal antibody, raised against human placental -galactosidase, it was observed that the structural locus for the -galactosidase polypeptide is located on chromosome 3. The nature of the involvement of chromosome 22 in the expression of human -galactosidase was elucidated by metabolic labelling of the hybrids with radioactive amino acids, immunoprecipitation with monoclonal and polyclonal antibodies against -galactosidase, followed by analysis via gel electrophoresis and fluorography.The data show that the presence of chromosome 22 coincides with the presence of a 32 kd protein. This polypeptide, the protective protein was previously shown to be intimately associated with human -galactosidase. In addition, the protective protein was found to be essential for the in vivo stability of -galactosidase by aggregating -galactosidase monomers into high molecular weight multimes. Both chromosome 3 and 22 are therefore necessary to obtain normal levels og -galactosidase activity in human cells. 相似文献
11.
Tadashi II Masayuki Kubota Satoshi Okuda Takashi Hirano Mamoru Ohashi 《Glycoconjugate journal》1995,12(2):162-172
Negative-ion fast atom bombardment tandem mass spectrometry has been used in the characterization of non-, mono-, di- and trisulfated disaccharides from heparin and heparan sulfate. The positional isomers of the sulfate group of monosulfated disaccharides were distinguished from each other by negative-ion fast atom bombardment tandem mass spectra, which provide an easy way of identifying the positional isomers. This fast atom bombardment collision induced dissociation mass spectrometry/mass spectrometry technique was also applied successfully to the characterization of di- and trisulfated disaccharides.Abbreviations FABMS
fast atom bombardment mass spectrometry
- CID
collision induced dissociation
- MIKE
mass analysed ion kinetic energy
- MS/MS
mass spectrometry/mass spectrometry
- HPLC
high performance liquid chromatography
- UA
d-gluco-4-enepyranosyluronic acid
- CS
chondroitin sulfate
- DS
dermatan sulfate
- HA
hyaluronan
- Hep
heparin
- HS
heparan sulfate
- UA(14) GlcNAc
2-acetamido-2-deoxy-4-O-(-d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA(14)GlcNAc6S
2-acetamido-2-deoxy-4-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA2S(14)GlcNAc
2-acetamido-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA2S(14)GlcNAc6S
2-acetamido-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA(14)GlcN6S
2-amino-2-deoxy-4-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA2S(14)GlcN
2-amino-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA2S(14)GlcN6S
2-amino-2-deoxy-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA(14)GlcNS
2-deoxy-2-sulfamino-4-O-(-d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA(14)GlcNS6S
2-deoxy-2-sulfamino-4-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA2S(14)GlcNS
2-deoxy-2-sulfamino-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-glucose
- UA2S(14)GlcNS6S
2-deoxy-2-sulfamino-4-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-glucose
- UA(13)GalNAc
2-acetamido-2-deoxy-3-O-(-d-Gluco-4-enepyranosyluronic acid)-d-galatose
- UA(13)GalNAc4S
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4-O-sulfo-d-galactose
- UA(13)GalNAc6S
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-galactose
- UA2S(13)GalNAc
2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-d-galactose
- UA2S(13)GalNAc4S
2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-4-O-sulfo-d-galactose
- UA2S(13)GalNAc6S
2-acetamido-2-deoxy-3-O-(2-O-sulfo--d-gluco-4-enepyranosyluronic acid)-6-O-sulfo-d-galactose
- UA(13)GalNAcDiS
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-4,6-di-O-sulfo-d-galactose
- UA(13)GlcNAc
2-acetamido-2-deoxy-3-O-(-d-gluco-4-enepyranosyluronic acid)-d-glucose. 相似文献
12.
Dr. V. R. Southgate 《Cell and tissue research》1971,120(3):420-449
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
13.
Lugovskoy EV Zolotareva EN Gogolinskaya GK Gritsenko PG Moroz ED Komisarenko SV 《Biochemistry. Biokhimii?a》2002,67(4):446-450
The present work deals with localization of previously unknown polymerization sites of the fibrin DD-fragment. D-dimer we obtained has a pronounced inhibitory effect on fibrin polymerization (IC50 = 0.06 M). The inhibitory effect of the D-fragment disappeared after reduction and carboxymethylation. However, polypeptide chains DD (B134-461) and DD (63-411)2 of the DD-fragment, isolated by preparative electrophoresis, displayed their inhibitory activity. For instance, the rates of fibrin protofibril lateral association were decreased twice in the presence of DD and DD chains at their molar ratios to fibrin of 0.40 and 0.15, respectively. The IC50 values for DD and DD were 0.24 and 0.10 M, respectively. Highly specific inhibition of protofibril lateral association suggests that the protofibril lateral association sites are located in B134-461 and 63-411 regions of the fibrin D-domain. Our data confirm those reported by Doolittle et al. regarding the -chain and a hypothesis about -chain of fibrin D-domain (Yang, Z., Mochalkin, I., and Doolittle, R. F. (2000) Biochemistry, 97, 14156-14161). 相似文献
14.
The properties of the -2-l-fucosyltransferases in submaxillary gland preparations from blood group ABH secrefors and non-secretors were compared. The level of activity in the non-secretor gland homogenates amounted to about 5% only of that found in the secretor gland preparations. The enzymes from the two sources differed in solubility properties, charge and affinities for donor and acceptor substrates. The enzyme from secretor glands showed a preference for acceptors with Type 1 [d-galactosyl(1–3)-N-acetyl-d-glucosamine] structures whereas the enzyme from non-secretor glands had a preference for Type 2 [d-galactosyl(1–4)-N-acetyl-d-glucosamine] structures.These results demonstrate that expression of the secretor gene (Se) is associated with a molecular form of the -2-l-fucosyltransferase that is different from the species present in the same tissue when theSe gene is not expressed. 相似文献
15.
Unravelling the factors that contribute to the formation and the stability of -sheet structure in peptides is a subject of great current interest. A -hairpin, the smallest -sheet motif, consists of two antiparallel hydrogen-bonded -strands linked by a loop region. We have performed a statistical analysis on protein -hairpins showing that the most abundant types of -hairpins, 2:2, 3:5 and 4:4, have characteristic patterns of 13C and 13C conformational shifts, as expected on the basis of their and angles. This fact strongly supports the potential value of 13C and 13C conformational shifts as a means to identify -hairpin motifs in peptides. Their usefulness was confirmed by analysing the patterns of 13C and 13C conformational shifts in 13 short peptides, 10–15 residues long, that adopt -hairpin structures in aqueous solution. Furthermore, we have investigated their potential as a method to quantify -hairpin populations in peptides. 相似文献
16.
Liying Yan Patricia P Wilkins Gerardo Alvarez-Manilla Su-Il Do David F Smith Richard D Cummings 《Glycoconjugate journal》1997,14(1):45-55
A defined set of oligosaccharides and glycopeptides containing -linked fucose were used to examine the specificity of the immobilized fucose-binding lectin Lotus tetragonolobus agglutinin (LTA1), also known as lotus lectin. Glycans containing the Lewis x determinant (Lex) Gal1-4[Fuc1-3]GlcNAc1-3-R were significantly retarded in elution from high density LTA-Emphaze columns. The lectin also bound the fucosylated lacdiNAc trisaccharide GalNAc1-4[Fuc1-3]GlcNAc. The lectin did not bind glycans containing either sialylLex or VIM-2 determinants, nor did it bind the isomeric Lea, Gal1-3[Fuc1-4]GlcNAc-R. Although 2-fucosyllactose Fuc1-2Gal1-4Glc) was retarded in elution from the columns, larger glycans containing the H-antigen Fuc1-2Gal1-3(4)GlcNAc-R interacted poorly with immobilized LTA. Our results demonstrate that immobilized LTA is effective in isolating glycans containing the Lex antigen and is useful in analyzing specific fucosylation of glycoconjugates. Abbreviations: LTA, Lotus tetragonolobus agglutinin; UEA-1, Ulex europaeus agglutinin-I; LNT, AAL, Aleuria aurantia agglutinin; Gal1-3GlcNAc1-3Gal1-3Glc; LNnT, Gal1-4GlcNAc1-3Gal1-3Glc; Lex, Lewis x antigen; Lea, Lewis a antigen; GDPFuc, guanosine 5-diphosphate--L-fucose 相似文献
17.
Lothar Diers 《Molecular & general genetics : MGG》1967,100(1):56-62
Summary Up to now Antirrhinum was classified as a typical example for a uniparentalmaternal inheritance of the plastids. However, the findings reported here prove that also the male gametophyte of Antirrhinum may occasionally transmit plastids into the egg. This conclusion is based on genetic experiments involving a form of the plastom mutant prasinizans which is described as gelbgrüne prasinizans. In contrast to all other plastid mutations known in Antirrhinum majus this mutant originated in Sippe 50 is completely viable. In plants containing plastids of this mutant type only, the mutant character is manifested during early growth stages. Cotyledons and first foliage leaves which are initially white or white yellow, slowly turn green and become indistinguishable from normal Sippe 50. Reciprocal crosses of green Sippe 50 with gelbgrüne prasinizans gave few variegated descendants; the others were exclusively plants identical with the maternal parent as far as leaf colour is concerned (Table). The variegated individuals cannot be gene mutants since selfing and crossing experiments showed non-mendelian inheritance. Furthermore it could be ruled out that in the cross Sippe 50 x gelbgrüne prasinizans the three variegated descendants represent spontaneous new plastom mutants because the pale tissue in these plants turned green in the same way as the paternal parent. Because of the typical greening of this mutant and since plastid mutations could be ruled out we have to conclude that plastids were transmitted by the pollen parent into the egg. There these plastids multiplied together with the maternal plastids giving rise to the chimeras after sorting-out of the two plastid types. This interpretation is supported by the observation of mixed cells in tissues where the leaf variegation is finely mosaiced. The results were possible only because the plastids of the pollen parent can be unequivocally recognised. 相似文献
18.
J. Ortel 《Entomologia Experimentalis et Applicata》1991,59(1):93-100
The parasitoid Pimpla turionellae L. (Hymenoptera, Ichneumonidae) was fed on Cd, Pb and Cd+Pb-contaminated food (33g Cd, 82g Pb and 33g Cd+82g Pb per gram food fresh weight, respectively). Significant decrease in the total lipid and protein content was found along with an increase in the water content particularly in Cd-contaminated parasitoids. 相似文献
19.
Adilson Leite Laura M. M. Ottoboni Maria Luiza P. N. Targon Marcio J. Silva Silvia R. Turcinelli Paulo Arruda 《Plant molecular biology》1990,14(5):743-751
Zeins from Zea mays L cv. Maya and coixins from Coix lacryma-jobi L. cv. Adlay were fractionated to obtain -, -, and -zein and -, -, and -coixin. The -coixins were composed of 4 polypeptide classes of 27 kDa (C1), 25 kDa (C2), 17 kDa (C4) and 15 kDa (C5) with solubility properties very similar to those of the 22 kDa and 19 kDa -zeins. Like the -zeins, the C1 and C2 -coixins corresponded to 80% of total Coix prolamins. The fraction corresponding to -coixin contained only one protein band of 22 kDa (C3). This coixin fraction has solubility properties similar to those of -zein and represents 15% of the total coixin. The -zein fraction was composed of a major 17 kDa protein band, while the -coixin fraction consisted of a mixture of - and -coixins.Polyclonal antibodies raised against C1 recognized C1 and C2 and cross-reacted strongly with the 22 kDa -zein, as did C4 and C5 antisera. The antiserum against -coixin showed strong cross-reaction with -zein. The homology between coixins and zeins was further investigated by using Southern hybridization analyses. The genomic DNA of maize and Coix were digested with several restriction enzymes and probed with cDNA clones representing 19 and 22 kDa -zeins as well as the 28 and 16 kDa -zeins. The Coix genome showed complex cross-hybridization sequences with the 22 kDa -zein cDNA, while no cross-hybridization was observed with the 19 kDa cDNA clone. The cDNA clone representing the 28 kDa -zein cross-hybridized with only one band of Coix genomic DNA, in contrast to the three bands observed in maize. This same Coix sequence also cross-hybridized with the cDNA clone representing the 16 kDa -zein. The relevance of these findings are discussed in the context of the origin of zein and coixin genes. 相似文献
20.
Summary Suspensions of endocrine pancreas cells were prepared by shaking collagenase-isolated rat islets of Langerhans in calcium-free buffer. When incubated with 1.0 mM substrate at pH 7.4, the cells split,P
i from 5-AMP at a rate of 87 nmol/h per g DNA, and from-glycerophosphate at a rate of 25 nmol/h per g DNAK
m for 5 AMP was about 54 M. Adenosine or theophylline inhibited the 5-AMP hydrolysis. Homogenization of the cells increased the activity toward 5-AMP by 23% and that toward-glycerophosphate by 115%. Injecting rats with cortisone had no effect on the 5-AMP hydrolysis by whole cells but significantly increased the activity in cell homogenates; the intracellular activity toward 5-AMP was more than doubled by the cortisone treatment. Staining whole islet cells for 5-AMP-splitting activity resulted in a demarcation of the cell periphery in control rats. Cells from cortisone-treated rats showed heavier deposits of reaction product, and their cell periphery did not stand out as clearly. It is suggested that 5-nucleotidase is largely an ectoenzyme in normal rat islet cells. The cells also contain an as yet unidentified intracellular phosphatase that seems to be solely responsible for the increased hydrolysis of 5-AMP in cortisone-treated rats. 相似文献