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1.
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   

2.
Summary On the basis of the histochemical activity of succinic dehydrogenase, only two fibre-types are distinguished in pigeon pectoralis major muscle. These are narrow Red and broad White. The histochemical activity of myofibrillar ATPase was studied in these two distinct fibre-types. Both fibre-types showed high activity for the ATPase. Red fibres of pigeon pectoralis were not alkali-labile, at incubation pH 9.4, as were the Type I fibres of both avian and mammalian muscles. Again unlike Type I fibres, the Red fibres of pigeon pectoralis lacked the characteristic activation of acid-preincubated ATPase reaction. Pigeon pectoralis Red fibres are known to posses some characteristics of fast-twitch fibres (e.g. high fat, considerable phosphorylase, fibrillenstruktur myofibrillar arrangement, focal en plaque pattern of nerve endings). It is emphasized, therefore, that the pigeon pectoralis Red fibres are not equivalent to Type I or slow-twitch, muscle fibres, but they are possibly fast-twitch fatigue resistent or Type II Red muscle fibres.  相似文献   

3.
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   

4.
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   

5.
Zusammenfassung Zwei Seren des Phänotypus Ch1SS, die unter Standardtestbedingungen keine Pseudocholinesteraseaktivität aufwiesen, wurden mit Hilfe der Stärkegel-Elektrophorese, der Mikromanometrie und mit immunologischen Methoden näher untersucht.Nach elektrophoretischer Auftrennung läßt sich in diesen silent gene-Seren eine Pseudocholinesteraseaktivität nachweisen; im Vergleich zu der Aktivität von Normalserum erscheint diese sehr gering und läßt sich nur in der c4-Zone erkennen. Die Identifizierung gelingt mit Hilfe spezifischer Färbeverfahren unter Verwendung verschiedener Substrate und Inhibitoren.Die quantitative Bestimmung von Pseudocholinesteraseaktivität im silent gene-Serum mit mikromanometrischen Methoden ergab eine Aktivität von 2–3% gegenüber den Kontrollen (Benzoylcholin als Substrat).Durch Immunisierung von Kaninchen mit gereinigtem Pseudocholinesteraseprotein wurden Antiseren erhalten; zwischen silent gene-Serum und diesen Antiseren konnten Präzipitationsreaktionen im Immuno-Diffusionstest, in der Immuno-Elektrophorese und mit einer Immuno-Adsorptionsmethode nachgewiesen werden. Diese Ergebnisse lassen annehmen, daß bei den von uns untersuchten Fällen das silent gene im Pseudocholinesterasepolymorphismus eine Enzymproteinsynthese steuert; das nachgewiesene Pseudocholinesteraseprotein scheint sich qualitativ von dem Enzymprotein des Normalserums zu unterscheiden.
Two sera without pseudocholinesterase activity corresponding to the homozygous phenotype Ch1SS are examined by electrophoretical, manometric, and immunological methods.These silent gene sera show no activity under the common conditions (spectrophotometric assay).After electrophoretical separation of silent gene serum an esterase activity is found which can be identified as pseudocholinesterase activity, although it is weak in comparison with the activity of usual sera. The pseudocholinesterase activity of silent gene serum can be demonstrated only in the zone c4 where 90% of the total activity is present if usual serum is inserted. The identification has been achieved by staining procedures applying several substrates and inhibitors.Quantitative estimation of this pseudocholinesterase activity was carried out by micromanometric assays with benzoylcholine as substrate. The activity of silent gene sera was 2–3% of normal serum.Antisera against human pseudocholinesterase-protein have been obtained by immunization of rabbits with a highly purified enzyme protein. Between these antisera and the homozygous silent gene sera precipitates were found in immuno double-diffusion tests and immunoelectrophoresis. They could be identified as pseudocholinesterase protein by esterase staining under various conditions.Quantitative estimations have been carried out by immuno-adsorption assays comparing the amount of antibody fixed by usual serum and by silent gene serum.The results presented in this paper suggest that the silent gene in pseudocholinesterase polymorphism induces in these two cases the synthesis of an enzyme protein which is similar to the enzyme protein of usual pseudocholinesterase. The weak activity is due to a qualitative difference between silent gene enzyme protein and the normal pseudocholinesterase protein. A structural alteration of the enzyme protein is assumed to be more likely than a quantitative difference in protein synthesis.


Einige der Ergebnisse dieser Arbeit wurden auf dem 2nd Meeting of the Federation of European Biochemical Societies, Wien 1965, vorgetragen.

Wesentliche Teile dieser Arbeit werden von R. A. Hofmann der Medizinischen Fakultät der Universität Freiburg i. Br. als Inauguraldissertation vorgelegt.  相似文献   

6.
    
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   

7.
Neuronic or decision equations, first proposed as a mathematical model of neural activity, have shown, after their exact, compact solution was found, typical behaviours that make them natural tools for General Systems studies. It is shown here that their mathematical investigation is remarkably furthered by generalizing the triangular inequality to polygonal ones. These permit the immediate computation of the tensorial expansion of linearly separable boolean functions, and exhibit clearly the connection between their continuous and discontinuous aspects.  相似文献   

8.
Summary Cytokinesis in the subsidiary cell mother cells (SMCs) ofZea mays leaves grown in the presence of 5 mM of caffeine solution is usually partially inhibited. A continuous wall strip, resembling a portion of the subsidiary cell (SC) wall, is laid down in the preprophase microtubule band (PMB) cortical zone. Sometimes, the incomplete SC (SC) wall grows centripetally in the absence of a phragmoplast and the gap becomes smaller or closes. The SC nucleus escapes through the SC wall gap into the larger SMC compartment and may fuse with the other nucleus.The aberrant SMCs (a-SMCs) pass through another division cycle, reattempting to produce a SC. A typical PMB is found in the SC space, in the site of the previous PMB. Moreover, in some preprophase SMCs, the cytoplasm adjacent to the SC wall is traversed by a small number of microtubules. The preprophase nuclei are partly or totally separated from the PMB by the perforated SC wall and may lie far from the latter.Usually, one mitotic spindle is assembled. The cycling paired polarized nuclei appear to synchronize and their chromosomes line up together on a single metaphase plate. Although the mitotic spindle axis is diversely oriented, one of its poles tends to be stabilized in the proximity of the SC wall gap. These divisions separate abnormal cells. Most or all the cell plate edges fuse with wall regions far from the PMB cortical zone. However, when some of them approach the SC wall strips, they are attracted and intersect their rims. In rare occasions the cell plate, invading the SC space is guided by the PMB cortical zone to create a SC-like curved wall portion, in absence of a daughter nucleus.Observations show that the cell plate arrangement in redividing aberrant SMCs is not subjected to a strict spatial control. The disorder of polarization sequence generated by the SC wall ring and especially the perturbation of the spatial (and functional?) relationship between PMB-PMB cortical zone and the nucleus—mitotic spindle is a causal factor of the variable cell plate arrangements.  相似文献   

9.
Summary This paper deals with the ultrastructure of two types of intranuclear inclusions, nuclear bodies and membranous lamellar bodies, present in hypothalamic pericytes of intact adult rats. The nuclear bodies exhibited simple and granular forms, whereas the membranous lamellar bodies were entirely made up of myelin-like membrane whorls.The occurrence of these bodies in nuclei of pericytes has never been previously reported. The origin and functional meaning of such structures is discussed in the light of recent ultrastructural and biochemical studies on nuclear inclusions.  相似文献   

10.
Structures of mitochondrial bc 1 complex have been reported based on four different crystalforms by three different groups. In these structures, the extrinsic domain of the Rieske [2Fe–2S]protein, surprisingly, appeared at three different positions: the c 1 position, where the [2Fe–2S]cluster exists in close proximity to the heme c 1; the b position, where the [2Fe–2S] clusterexist in close proximity to the cytochrome b; and the intermediate position where the[2Fe–2S] cluster exists in between c 1 and b positions. The conformational changes betweenthese three positions can be explained by a combination of two rotations; (1) a rotation of theentire extrinsic domain and (2) a relative rotation between the cluster-binding fold and thebase fold within the extrinsic domain. The hydroquinone oxidation and the electron bifurcationmechanism at the QP binding pocket of the bc 1 complex is well explained using theseconformational changes of the Rieske [2Fe–2S] protein.  相似文献   

11.
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   

12.
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   

13.
Substantial quantities of mRNA encoding the abundant Em polypeptide accumulate, in planta, in developing embryos of maize (Zea mays L.). By contrast, accumulation of Em mRNA is only barely detectable in embryos with the vp-5/vp-5 genotype [an abscisic acid (ABA)-deficient viviparous phenotype]. Em mRNA is not detectable within viviparous embryos of the vp-1/vp-1 genotype that are non-responsive to ABA. Culture of immature wild-type and vp-5/vp-5 embryos in the presence of exogenous ABA or of an osmotically active agent prevents precocious germination and results in expression of the Em genes. When vp-1/vp-1 embryos are cultured under similar conditions, only the application of osmotic stress prevents precocious germination. However, Em mRNA does not accumulate either in ABA-treated or stressed, arrested embryos, indicating a requirement for ABA perception through a VP-1-mediated mechanism for Em gene expression. Nevertheless, vp-1/vp-1 embryos do show both ABA and stress responses at the molecular level. Treatment with ABA causes the accumulation of mRNA encoding a polypeptide of approx. 30 kDa, whilst osmotic stress induces the accumulation both of a 30-kDa polypeptide and a set of approx. 20-kDa polypeptides. This indicates the existence of discrete, parallel ABA and stress response pathways in developing maize embryos.Abbreviations ABA abscisic acid - cDNA copy-DNA - DAP days after pollination - kDa kilodaltons - MS Murashige and Skoog medium - LEA late embryogenesis abundant - NEpHGE non-equilibrium pH gradient gel electrophoresis - SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis  相似文献   

14.
Zusammenfassung An Laboratoriumszuchten vonReticulitermes lucifugus Rossi undReticulitermes flavipes Kollar (aus den Hamburger Befallsgebieten) werden Beobachtungen zur Biologie der Ersatzgeschlechtstiere mitgeteilt. Für die Durchführung dieser Beobachtungen wurden besondere Schaunester eingerichtet. Folgende Punkte der beobachteten Verhaltensweisen werden hier hervorgehoben: Die Nymphen der Ersatzgeschlechtstiere sammeln sich stets in Herden von 80–100 Einzeltieren und werden von einer Gruppe Arbeiter (als Hütehunde) bewacht. Die Arbeiter halten die Nymphen auf einem engen Raum zusammen und versuchen andere Nestgenossen von den Nymphen fernzuhalten. Alle ein bis zwei Tage wechseln die Herden ihren Standort. Das Weiterziehen geschieht gleichfalls in Form von Herden.Die Ernährung der Nymphen geschieht auf stomodealem Wege durch die Arbeiter. *** DIRECT SUPPORT *** A0180089 00007  相似文献   

15.
A model of associative memory for time varying spatial patterns is proposed and simulated on a digital computer. This is a network composed of many neuron-like elements, and shows an ability for associative memory similar to that of the brain.Suppose a number of sequences of spatial patterns are presented to this network, for example, 12345, ABC, and so on. Then, these patterns are memorized in the network. After that, if any part of one of these sequences, say 23, is presented to the circuit, the rest of the sequence, 45, is recalled following to it. It resembles to such a situation — if we hear a part of a melody which we have memorized in the past, the rest of the melody is recalled even after it is stopped half-way. Although the recalled patterns are not always 100% correct, they are not completely destroyed even if the presented patterns are imperfect.  相似文献   

16.
R. Jarosch 《Protoplasma》1968,65(4):363-377
Zusammenfassung Es werden verschiedene Vorgänge an sehr zarten Pseudopodien beschrieben und mit Hilfe der an submikroskopischen Fibrillen (schraubig gebauten Mikrofibrillen und Mikroröhrchen der Elektronenmikroskopie) auftretenden Torsionsspannungen und Rotationen gedeutet.
On the dynamics of slender pseudopodia of bog amebae
Summary Different processes which occur on very slender pseudopods are described. They are interpreted with the help of torsional forces and revolutions of the submicroscopic fibrils (helical microfibrils and microtubules in electron microscopy).
  相似文献   

17.
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   

18.
Summary Twenty two basidiomycetes, mostly white rot fungi, were grown on wheat straw. Lignin-, cellulose-, and hemicellulose-degradation was recorded in order to find a species growing on lignin preferably. The oyster-mushroomPleurotus sp. florida showed fastest delignification of all tested fungi.Straw pretreated by this fungus was fermented anaerobically to biogas. The gas yield produced from myco-straw is twice the amount from untreated straw.  相似文献   

19.
Silver staining the chromosome scaffold   总被引:5,自引:0,他引:5  
Cytological silver-staining procedures reveal the presence of a core running along the chromatid axes of isolated HeLa mitotic chromosomes. In this communication we examine the relationship between this core and the nonhistone chromosome scaffolding, isolated and characterized in previous publications from this laboratory. When chromosomes on coverslips were subjected to the steps used for scaffold isolation in vitro and subsequently stained with silver, the characteristic core staining was unaffected. Control experiments suggested that the core does not contain large amounts of DNA. When scaffolds were isolated in vitro, centrifuged onto electron microscope grids, and stained with silver, they were found to stain selectively under conditions where specific core staining was observed in intact chromosomes. These results suggest that the nonhistone scaffolding is the principal target of the silver stain in chromosomes.  相似文献   

20.
Onset of nucleic acid synthesis during germination of Pisum sativum L.   总被引:3,自引:3,他引:0  
Summary Measurments of total nucleic acid content of the embryonic axis indicated that massive net synthesis of both DNA and RNA was initiated at approximately 30 h after the onset of germination. The onset of net nucleic acid synthesis was marked by an increase in the rate of incorporation of [3H]thymidine into DNA, and of [3H]orotic acid and [3H]uridine into both DNA and RNA. rRNA was usually more heavily labelled than tRNA, but was not preferentially accumulated, suggesting a grater rate of turnover of rRNA than tRNA. Some incorporation of precursors occurred prior to the onset of net nucleic acid synthesis, particularly into RNA. This was taken to represent nucleic acid turnover. There was no evidence that the scavenging pathways for nucleotide biosynthesis were more important than the normal pathways in contributing precursors for net nucleic acid synthesis.  相似文献   

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