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1.
A -amylase (EC 3.2.1.2) was identified in the outer pericarp (P) of developing seeds of wheat (Triticum aestivum L.) and compared with the well known -amylase which is synthesized during seed development in the starchy endosperm (E). The enzyme P already exists in the tissues before anthesis and vanishes at the time when E starts to accumulate. The isoelectric-focusing patterns of P and E are very similar. The relative molecular weight (Mr) of P is slightly higher than that of E (66 and 64.5 kDa, respectively). Both P and E exhibit common epitopes in addition to epitopes specific for each of them. The two enzymes were identified in small amounts in the green tissues of the developing seeds (inner pericarp and testa). No antigenic difference was detected between P and the -amylases of roots and leaves.Abbreviations P pericarp -amylase - E endosperm -amylase - IS1 anti--amylase immune serum - IS2 anti- and anti- amylase immune serum - IS3 anti- amylase immune serum - IEF isoelectric focusing - IgG immunoglobulin G The authors thank Dr. P. Ziegler (Universität Bayreuth, FRG) for stimulating discussion and for useful suggestions during the writing of the text. The authors thank Miss C. Mayer for her skillful technical assistance.  相似文献   

2.
The primary purpose of these studies was to link together concepts related to attention/working memory and feedforward/feedback activity using MEG response profiles obtained in humans. Similar to recent studies of attention in monkeys, we show early spike-like activity (<200 ms poststimulus), most likely reflecting an early transient excitatory response mixed with feedback influences, followed by slow-wave activity (>200 ms poststimulus) in MEG cortical response profiles evoked by a visual working memory task. We experimentally dissociated the early transient activity from the later sustained activity (predominately feedback) by conducting an auditory size classification task. Words, representing common objects, evoked activity in occipital cortex (presumably due to imagery) even though visual stimuli were not present in this task. The initial spike was absent from the response profile obtained from occipital cortex, leaving only slow-wave activity, thereby allowing us to characterize or profile feedback activity in this situation. Attention or task relevance enhanced the initial spike and slow-wave activity in visually responsive areas. Prefrontal activity, along the superior frontal sulcus, evoked by the working memory task, was active later in time than initial activity in visual cortex and later than the earliest effect of attention modulation in visual cortex.  相似文献   

3.
This paper explores the social and cultural organization of Iranian emotional discourse and its transformation in post-revolutionary Iran. First, the Moharram dramas we participated in during field research are described, indicating how these performances organized a prototypical view of the social order, the self, and the passions. Using Kapferer's distinction between transcendental and transformative rituals, we argue that these dramas were traditionally organized as transcendental rites. Second, data on grieving rituals and depressive illness among Iranians is introduced, focusing on the transformative qualities of mourning rites and suggesting an interpretation of depression as a failure of the work of culture. Third, the appropriation of these symbolic forms of society, self, and the emotions by the current Iranian Islamic state and the role of the state in defming the meaning and legitimacy of emotions and their expression is analyzed.  相似文献   

4.
Hybridizations ofElymus nutans andE. jacquemontii were carried out with one species ofPseudoroegneria (S genome), and 20Elymus species, each containing either of the SH, SY, SYH, or SYW genomes. Chromosome configurations were analysed at metaphase I of the two target taxa and their interspecific hybrids. It is concluded that (i)E. nutans is an allohexaploid containing the SYH genomes, andE. jacquemontii is an allotetraploid having the SY genomes; (ii) the genomic affinity is associated with the geographic distance between the species studied; (iii) minor genomic structural rearrangements have occurred within the hexaploid taxon ofE. nutans.  相似文献   

5.
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   

6.
The in vitro effects of -L-glutamyltaurine on different stages of excitatory aminoacidergic neurotransmission were tested with -D-glutamyltaurine as reference. -L-Glutamyltaurine enhanced the K+-stimulated release of [3H]glutamate from cerebral cortical slices (25% at 0.1 mM) and slightly inhibited the uptake by crude brain synaptosomal preparations (about 10% at 1 mM). -L-Glutamyltaurine was also a weak displacer of glutamate and its agonists from their binding sites in brain synaptic membrane preparations, being, however, less selective to quisqualate (QA) sites than -D-glutamyltaurine. The basal influx of Ca2+ into cultured cerebellar granular cells was not affected by 1 mM -L-glutamyltaurine, but the glutamate- and its agonist-activated influx was significantly inhibited in low-Mg2+ (0.1 mM) and Mg2+-free media. The glutamate-evoked increase in free intracellular Ca2+ and the kainate-activated formation of cGMP in cerebellar slices were both markedly inhibited by 0.1 mM -L-giutamyltaurine. We propose that -L-glutamyltaurine may act as endogenous modulator in excitatory aminoacidergic neurotransmission.  相似文献   

7.
We report DNA sequence variation in 861 bp of the mitochondrial cytochromeb gene from 10 species of the dasyurid marsupial subfamily Phascogalinae (including the New Guinean genusMurexia) and an outgroup planigale (Planigale ingrami). Phylogenetic analyses of these sequences indicate that (1) the subfamily consists of three major clades corresponding to (a)Phascogale, (b) AustralianAntechinus, and (c) New Guinean Antechinus andMurexia; (2) Antechinus habbema constitutes the earliest branch of the New Guinean clade; and (3); Antechinus melanurus and A. naso are sister species within the New Guinean clade. Among Australian antechnuses,A. stuartii andA. swainsonii are more closely related to each other than either is toA. flavipes, a result that is seemingly at odds with all previous systematic studies. Although resolution is limited, it appears thatAntechnius andMurexia species form a clade to the exclusion ofPhascogale. This relationship suggests that male semelparity is not a strong synapomorphy for Australian antechinuses and phascogales, despite its apparent physiological similarity in the two groups.To whom correspondence should be addressed.  相似文献   

8.
New quantitative J correlation experiments are used for measuring all two- and three-bondcouplings between 15N and aliphatic side-chain carbons in proteins uniformly enriched in 13Cand 15N. Results show that 3JNC and 2JNC invariably are very small.Therefore, a simple and relatively sensitive two-dimensional spin-echo difference experimentcan be used to identify residues with a 3JNC coupling substantially larger than 1Hz, indicative of a trans arrangement between N and C. This measurement thereforeprovides 1 angle information for residues with an aliphatic C carbon, andthereby also aids in making stereospecific assignments of H resonances. Experimentsare demonstrated for ubiquitin and for a complex between calmodulin and a 26-residuepeptide.  相似文献   

9.
Summary Secretory activities of bicellular microhairs from grasses belonging to the subfamilies Chloridoideae, Arundinoideae, Panicoideae, and Bambusoideae, and including the chloridoid, panicoid and Enneapogon microhair morphological types, have been investigated. Light microscopic histochemistry indicated that all microhairs studied secrete polysaccharide and protein (or glycoprotein), including those which also secrete salt. Localization of polysaccharide at ultrastructural level using periodic acid-thiocarbohydrazidesilver proteinate staining revealed that in panicoid type microhairs dictyosomes are involved in polysaccharide secretion, whereas in the chloridoid and Enneapogon types partitioning membranes seem to be involved instead.Abbreviations Ag silver precipitates representing localization of polysaccharide - BC basal cell - C cuticle - CC cap cell - CH cuticular chamber - CN system of membrane bound channels and vesicles - CP chloroplast - CW cell wall - D dictyosomes - M mitochondria - N nucleus - PTM partitioning membranes - RER rough endoplasmic reticulum - S secretory material - St starch grain - US unstained dictyosome cisternae - V vesicle  相似文献   

10.
Two sets of backcross matings were performed to test for linkage between genes coding for the Ia-like antigens (Ia) and the B erythrocyte antigens (Ea-B) of the chicken. Evidence is presented which indicates that the la antigens are determined by a single codominant locus and that theEa-B and Ia loci are on the same chromosome. Failure to detect a single recombinant between theEa-B and Ia loci out of 208 progeny suggests close linkage of the two genes with a map distance of up to about 2 centimorgans. The Ia genes are thus included in theB major histocompatibility complex of the chicken.  相似文献   

11.
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   

12.
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   

13.
The major proteins of baboon milk were identified as -lactoglobulin (LG), -lactalbumin (LA), lysozyme, lactoferrin, casein, and albumin by immobiline isoelectric focusing, SDS-PAGE, immunoblotting of gels with rabbit antisera to human LA, lysozyme, and albumin and bovine LG and casein, and N-terminal sequencing of proteins blotted from gels. The first 30 N-terminal residues of baboon LG are identical to those of macaque (Macaca fasicularis) LG except for a (D/N) polymorphism at residue 2. The complete cDNA sequence and derived amino acid composition of LG were elucidated using RT-PCR amplification of poly(A)+ mRNA purified from lactating mammary gland. Baboon LG consists of 168 amino acid residues (Mr 20,750) and is the longest LG identified to date. LG and LA polymorphisms with three (A, B, and C) and two (A and B) variants, respectively, were detected by immobiline IEF, pH 4–6, of individual baboon milk samples at varying stages of lactation.  相似文献   

14.
    
The distribution and use of the element kit as terminal part of the song of Chaffinches was studied in 16 . The frequency of occurrence of the kit was dependent on individual and on song types, and the kit was omitted significantly more often then any other part of the song pattern. The specific character of the kit as a terminal element, possible proximate factors for its occurrence, and the question whether it is a hetero-specific imitation are discussed.  相似文献   

15.
Summary The 7S nerve growth factor molecule, found in the mouse submandibular gland, is comprised of three distinct protein subunits named , and -NGF. In this paper, radioimmunoassays specific for each subunit were used to measure the concentrations of these subunits in homogenates of mouse submandibular gland. It was determined that there were excess concentrations of both the and subunits, more than enough to bind all of the -NGF in the gland to form 7S-NGF. The radioimmunoassay data was confirmed by gel filtration experiments. In the gel filtration experiments, the excess and subunits eluted at positions which would indicate that these excess subunits were free and not bound in the 7S-NGF complex. The identity of the excess and subunits was substantiated by ion exchange chromatography, isoelectric focusing polyacrylamide gels and immunoblotting experiments. In conclusion, there are considerable quantities of and subunits present in the submandibular gland which are not bound to -NGE The functional significance of these excess concentrations of the and subunits is not known.  相似文献   

16.
The high occurrence in large intestine epithelial cells from pig of a -N-acetylgalactosaminyltransferase with a substrate specificity very similar to that of the Sda 1,4-N-acetylgalactosaminyltransferase from other tissues is reported. The enzyme strictly recognized the NeuAc2,3Gal terminal sequence ofN- andO-linked oligosaccharides bound to glycoproteins. The transferase activity required Mn2+ and an optimum pH of 7.4. In contrast to the kidney Sda-enzyme from humans and other mammals, the microsomal fraction of pig colonic cells expressed a very high activity even in the absence of Triton X-100. A rapid procedure is presented for the large scale preparation of GalNAc1,4(NeuAc2,3)Gal1,4Glc from NeuAc2,3Gal1,4Glc. The biosynthesized tetrasaccharide was completely resistant to the action of neuraminidase fromVibrio cholerae, whereas about 60% ofN-acetylneuramic acid was cleaved by neuraminidase from Newcastle disease virus. HPLC separation of different compounds is reported.  相似文献   

17.
Zusammenfassung 1. Die Entwicklung vonStephanopyxis turris sowie die zu ihrer Untersuchung geeigneten Methoden werden beschrieben und diskutiert.2. Der vollständige Lebenszyklus einer zentrischen Diatomee nach Beobachtungen im Leben und mit den Grundzügen der zugehörigen Karyologie in Mitose, Meiosis, Befruchtung und Auxosporenbildung sowie Entstehung und Keimung der Dauersporen wird erstmalig dargestellt (Abb. 18).3. Neuartige Beobachtungen betreffen Kollaps, Blitztod und Lichtresistenz, die Dritte Linie, die Darstellung von Kern und Spindel in Mitose und Meiosis sowie die mit Kernkonkurrenz abschließenden acytokinetischen Karyokinesen in Oogon und Auxospore im Leben, die Keimung der Dauersporen, den lichtmikroskopischen Nachweis der Kieselschuppen in der Auxosporenmembran.4. Die Entwicklungsvorgänge werden vergleichend diskutiert und dabei die Termini depauperierende Teilung und heterovalvate Zytokinese in Vorschlag gebracht.5. Weitere Überlegungen gelten dem cyclischen Turgeszenzwechsel der Diatomeenzelle.6. Die Methode der Vegetativen Zellvergrößerung erlaubt es,Stephanopyxis-Klone beliebiger Breite aber unveränderten Genotypus für das Experiment bereitzustellen.
Ontogenetic investigations on centric diatoms IVThe planktonic diatomStephanopyxis turris — its treatment and life history
This paper presents a detailed account of the life cycle, development and cellular mechanics of the centric diatomS. turris. Special attention is paid to culture methods, nutritional requirements and the mechanism of vegetative cell enlargement. Instructions are outlined for experimental manipulations of developmental features. Various aspects of development are treated in details, e. g. cellular structures, cell division and morphogenesis, development and germination of resting spores, differentiation of gametangia (spermatogonangia, spermatogonia and oogonia), meiosis in the gametocytes, fertilization and auxospore differentiation (including the formation of the rejuvenated first cell and the accompanying metagamic mitoses).S. turris has one-egged oogonia. Its spermatogonangia develop their spermatogonia according to theBiddulphia granulata-type and their spermiums according to theMelosira-type (Fig. 18). Two new termini, i. e. heterovalvate cytokinesis and depauperizing mitosis are introduced (p. 232, p. 238). Among the more important results are observations on karyokinesis in vivo, meiosis and karyogamy, and on the peculiar process of destruction of supernumerary nuclei following each karyokinesis in the oocyte, and later in the young auxospore. Relations between osmotic cell rhythms, karyokinetic cycle and morphogenesis are discussed at the end of the paper.


Herrn Professor Dr.Adolf Bückmann zum 65. Geburtstag in Verehrung gewidmet.

Diese Studie enthält Teile der Dissertation vonG. Drebes.  相似文献   

18.
Heme oxygenase1, the major inducible isoform of heme oxygenase (HO), can be induced by heme and numerous other physical and chemical factors, many of which cause cellular stress. This has led to the realization that HO1 is a major highly conserved stress or heat shock protein. Recent work has implicated activation of mitogenactivated protein kinases and other kinases in the mechanism of induction of HO1, and suggested that signal transduction pathways through tyrosine kinases are involved in induction of HO1 gene expression by stress inducers. We hypothesized that phenylarsine oxide (PAO), an inhibitor of protein tyrosine phosphatases (PTPs), might up-regulate the HO1 gene. Here, we show that a remarkably brief (1–15 min) exposure of normal hepatocytes to low concentrations (0.5–3 M) of PAO produces a marked increase in mRNA and protein of HO1. This increase is comparable to the level obtained by addition of heme (20 M), and occurs without producing changes in cellular glutathione levels or stabilization of HO1 message. Preincubation of cells with inhibitors of protein synthesis decreased the ability of PAO to increase levels of HO1 mRNA, suggesting that the inductive effect requires de novo protein synthesis. Addition of thiol donors abrogated the PAOmediated induction of HO1 in a dose dependent fashion. Addition of genistein, a tyrosine kinase inhibitor, blunted the induction produced by both PAO and heme. After brief incubations with PAO or heme, cell extracts showed comparable increases in levels of protein tyrosine phosphorylation in general, and specifically in ZAP70 kinase. Our results are consistent with the proposition that induction of HO1 by PAO involves inhibition of specific PTP(s), and that the mechanisms of induction of HO1 by PAO and by heme may share some common pathways.  相似文献   

19.
In this essay I argue that Ernst Mayr's idea that the emergence of evolutionary biology in Western thought was delayed by the pernicious influence of the false ideologies of Platonism, Christianity, and physicalism is ahistorical and anti-evolutionary, that similar ideas, especially his antipathy to physicalism, prejudice his account of the transformation of natural history and medical science into biology, that his organicist resolution of the perennial conflict between mechanism and vitalism is an unstable compound of semi-holism and semi-mechanism, that his conception of biology as the true bridge between the sciences and the humanities, ethics, and social theory is open to question (especially as to the adequacy of the theory of natural selection to account for every aspect of human nature), and that his depiction of science as the sovereign key to understanding everything known to exist or happen in this universe cannot be justified at the bar of reason.  相似文献   

20.
Summary Two intracapillary (IC) media feed protocols termed media rich and media lean were examined in an effort to understand the effect of this variable on hollow fiber cell cultures. The media rich protocol emphasized a high volume IC media per day (5 liters) containing no serum and a normal amount of extracapillary (EC) media serum (10% v/v). Alternatively, the media lean protocol used up to 1.0 liter of IC media per day containing 5% v/v serum and increased EC media serum (20% v/v). Both protocols produced substantial amounts of antibody in 25 days using HFN7.1 hybridoma cells (ATCC CRL 1606), however the media rich protocol produced twice as much antibody as the media lean protocol. The metabolism of the cells was dramatically different as measured by glucose uptake rate (GUR) with media lean cells having a six-fold lower GUR. Our results indicate that the media rich protocol is useful for producing larger amounts of antibody in a short time frame. The media lean protocol may be considered when the production costs of antibody, particularly media and serum, is the overriding concern.  相似文献   

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