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1.
We have used restriction fragment length polymorphism (RFLP) analysis and DNA sequencing to characterize two distinct DRB1 alleles expressed on DRw52 and DQw7-associated haplotypes but not readily defined by conventional DR serology. These two haplotypes, designated HLA-D HAG and PEV, react variably with DRw13(w6), DRw14(w6), and the more broad DR 3+6 antisera. Analysis of RFLP revealed that HLA-D HAG and PEV are associated with different DRw52 variants, and that HAG is indistinguishable from DRw18(3) haplotypes. Sequencing of the HAG and PEV DRB1 genes showed each to represent novel alleles. Nevertheless, these sequences show similarities with the other alleles of the DR5, w6, and w8 family. HAG (DRB1*1303) appears to have arisen either from two recombinational events involving at least three DRB1 sequences (DRB1*1101, DRB1*0803, DRB1*0401) or from a single recombinational event together with multiple point mutational events. PEV appears to represent a DRB1*1301-1302/DRB1*1101 recombinant allele, with recombination having occured in the region of bases 175 – 198. The results of this study suggest that the DRw52 family haplotypes is derived from a relatively restricted number of ancestral sequences, with diversity among DRB1 alleles within this family arising through gene conversion or recombination events.  相似文献   

2.
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   

3.
This study provides a critical historical review and analysis of the variety of human expressions which have been erroneously labeled under the grandiose category mass hysteria. It is argued that Western science reductionist approaches to the classification of mass hysteria treat it as an entity to be discovered transculturally, and in their self-fulfilling search for universals systematically exclude what does not fit within the autonomous parameters of its Western-biased culture model, exemplifying what Kleinman (1977) terms a category fallacy. As a result of objectivist methodologies, the etiology of actions labeled as mass hysteria is typically viewed as deviant, irrational or abnormal behavior resulting from a malfunctioning proper social order. However, what constitutes the correct social order is a function of a researcher's historical sociocultural and/or scientific milieu. This study reviews the problem, advocating Geertz's (1973) culturally relativistic approach to understanding various cross-cultural behavior that is sensitive to and tolerant of the unique context and milieu of participants. Mass or epidemic hysteria is viewed as an invention of Western psychiatry and should be abandoned and replaced with the term collective exaggerated emotions. Instead of attempting to discover a neatly packaged, unitary external disease entity, the focus of a meaning-oriented approach emphasizes the deciphering of foreign realities, semantic networks and symbol systems.  相似文献   

4.
Embryogenetic pathways differ markedly among monotremes, marsupials, and placentals, and their analysis provides information of fundamental importance to recognition of mammalian evolutionary directions. The cap of cuboidal cells of the marsupial late unilaminar blastocyst, generally known as the embryonic area, probably is induced to form (prior to origin of Hensen's node) by signals from earliest hypoblastic cells (anterior visceral endoderm). The thickened cap is a medullary plate of sauropsid terminology because it includes epiblastic cells presumptive to neurectoderm (including neural crest), Hensen's node, primitive streak, and gut endoderm. The remainder of the definitive embryo (i.e., parts of epidermal origin, including ectodermal placodes) derives from squamous ectoderm (surrounding the medullary plate) of the blastocyst's ill-named trophoblastic area. Amniotic ectoderm develops farther distally within the trophoblastic area. The autapomorphic inner cell mass (ICM) of placental mammals is homologous to medullary plate of the marsupial blastocyst plus morphologically undefined, proximal parts of surrounding ectoderm (of the trophoblastic area). Considerations of early cell lineages in marsupials are greatly affected by recognition that the boundary between future embryonic and extra-embryonic tissues does not match the margin of the medullary plate (i.e., embryonic area). Marsupials and monotremes largely conform to sauropsid early embryogenesis, but placentals express, at earliest developmental stages, innovations unique within Amniota that are linked to early establishment of the brain. Neonatal marsupials and hatchling monotremes are extremely altricial and closely comparable anatomically/physiologically; they share a temporal pattern in combining early morphogenesis of craniofacial features (related to suckling) with deferral of telencephalic completion into postnatal/posthatching life. Placentals contrast greatly in establishing the central nervous system prior to rudiments of the cranial skeleton and associated musculature, and they complete essentials of forebrain development before birth. Comparative evidence from transitory periderm suggests that primordial eutherians had extremely altricial hatchlings or newborns, whichever was the mode of early development. Details remain unknown about the origin of the unique specialization of ICM plus encapsulating trophoblast from the more generalized blastula of ancestral synapsids.  相似文献   

5.
The paper characterizes Darwin's theory, providing a synthesis of recent historical investigations in this area. Darwin's reading of Malthus led him to appreciate the importance of population pressures, and subsequently of natural selection, with the help of the wedge metaphor. But, in itself, natural selection did not furnish an adequate account of the origin of species, for which a principle of divergence was needed. Initially, Darwin attributed this to geographical isolation, but later, following his work on barnacles which underscored the significance of variation, and arising from his work on botanical arithmetic, he supposed that diversity allowed more places to be occupied in a given region. So isolation was not regarded as essential. Large regions with intense competition, and with ample variation spread by blending, would facilitate speciation. The notion of place was different from niche, and it is questioned whether Darwin's views on ecology were as modern as is commonly supposed. Two notions of struggle are found in Darwin's theory; and three notions of variation. Criticisms of his theory led him to emphasize the importance of variation over a range of forms. Hence the theory was populational rather than typological. The theory required a Lamarckian notion of inheritable changes initiated by the environment as a source of variation. Also, Darwin deployed a use/habit theory; and the notion of sexual selection. Selection normally acted at the level of the individual, though kin selection was possible. Group selection was hinted at for man. Darwin's thinking (and also the exposition of his theory) was generally guided by the domestic-organism analogy, which satisfied his methodological requirement of a vera causa principle.  相似文献   

6.
The most commonly quoted mechanism of the coupling between the electrochemical proton gradient and the formation of ATP from ADP and Pi assumes that all states of the F1 portion of the ATP synthase have subunits in tight, loose, and open conformations. Models based on this assumption are inconsistent with some of the available experimental evidence. A mechanism that includes an additional subunit conformation, closed, observed in the rat liver structure overcomes these difficulties.  相似文献   

7.
Summary The seasonal progression of phenophases in 21 shrub species of the Chilean matorral was analyzed. Five modules or basic units that are responsible for the aboveground architecture of the plants were characterized. These modules appear to be organized in seven different spatial arrangements. In drought-deciduous species a module type with an absolute short shoot with limited apical growth, leafy or spiny, predominated. In evergreen species long shoot and temporal leafy short shoot module types were more frequent. The spatial arrangement of morphologically different modules and the temporal sequence of their formation allow a dynamic interpretation of the modular architecture of the plants.  相似文献   

8.
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   

9.
J. Kojima 《Insectes Sociaux》1996,43(4):411-420
Summary Colonies of an Australian swarm founding polistine wasp,Ropalidia romandi, on the Atherton Tableland, Queensland, manage perennial nests by practicing seasonal colony activity. In summer nests, most cells were occupied by immatures of all developmental stages. The proportion of cells that did not contain immatures increased towards winter, when most nest cells did not contain immatures and half of these winter nests had rather large amounts of nectar deposited in empty cells. While the visits to tree flowers byR. romandi were not frequent in summer, nearly 60 % of insects collected on tree flowers in winter wereR. romandi. With such seasonal switching in the modes of colony reproductive activity and of nectar foraging behavior,R. romandi responds to its physical and biotic environment. In this way,R. romandi may be able to continue colonies throughout the year, with much reduced level of colony activity in winter, in areas with seasons that are unfavorable for reproductive activity of a colony.  相似文献   

10.
A. M. M. Berrie  J. Robertson 《Planta》1976,131(3):211-215
Summary Abscisic acid (ABA) has been unequivocally identified as an endogenous component of seeds of Grand Rapids lettuce. Both free and bound ABA levels were followed during imbibition at various temperatures but no clear role for ABA in the imposition of thermodormancy emerged. Furthermore it was apparent that different seed batches showed different ratios of free to bound ABA and patterns of changes. An unsuccessful attempt was made to identify bound ABA, presumed to be the glucosyl ester.Abbreviations ABA abscisic acid - ABA Me ester methyl abscisate - ECD electron capture detector - FID flame ionisation detector - GC-MS combined gas liquid chromatography, mass spectrometry - GLC gas liquid chromatography - PVP polyvinyl-pyrrolidone - TLC thin layer chromatography  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.
Conclusion Even a cursory look at the ethnographic literature on other Northwest Coast societies reveals some striking similarities with the Tlingit way of conceptualizing aristocrats as special persons. Thus the Kwakiutl referred to their chiefs as real or complete people, who were heavier than commoners. The Coast Tsimshian called their highest aristocrats real or ripe persons, in contrast to the low-ranking ones, who were described as unhealed or green. The Coast Tshimshian also referred to their chiefs as strong, heavy, and solid like a rock. The neighboring Gitksan contrasted the chiefs, described as people who were good and clean and stayed put, with the commoners, who were said to be dirty, ignorant, and always moving around. Because spirits of the dead liked to return to persons who were clean and showed respect by giving away wealth and feasts, there was considerable moral and practical pressure on the aristocrats to remain pure, train knowledgeable and clean heirs, and continue potlatching. Finally, among the Haida, rank was tied to a wider system of symbolic classification, associating aspects of food, space, clothing, ritual pollution and the ethic of industry with attributes of seniority.While some of the symbolic associations of aristocratic status are culture specific, others are present in several, if not all, of the NWC cultures. What we need is a comparative symbology of aristocratic status, which would combine the reanalysis of the existing ethnographic data with the introduction of some new materials that can still be obtained in the field. Such work would be the best tribute to Irving Goldman himself and to our common illustrious ancestors—Franz Boas and Marcel Mauss.Sergei Kan is Professor of Anthropology at Dartmouth College.  相似文献   

13.
Zusammenfassung Fetale menschliche Pankreaszellen bilden sowohl spontan auf zuerst gewachsenem Zellrasen (self-aggregation) als auch in Rollröhrchen (48 rph) (rotation-mediated-aggregation) histotypische Aggregate, die A- und B-Zellen enthalten. In der Nährlösung dieser 6–17 Tage lang gewachsenen Gewebestückchen konnte, Insulin (=IRI=immunoreactive-insulin) nachgewiesen werden.
Monolayer cultures of pancreatic tissueII. Formation of histotypic aggregates from cell suspensions of fetal human pancreas
Summary Fetal Pancreas cells of man, whether in self-aggregation or rotation-mediated-aggregation, form spontaneously histotypical aggregates containing A- and B-cells. It is possible by means of an immunological method to determine insulin (=IRI=immuno-reactive-insulin) in the nutrient medium of these 6 to 17 days old tissue aggregates.
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14.
F. Kozár 《Oecologia》1987,73(1):99-104
Summary A large scale survey, covering some 25 million km2 of Eastern-Europe, provided distributional data, and a more detailed picture on factors determining species composition and abundance of scale-insects colonizing deciduous orchard trees. No interspecific competition or competitive situations were detected among the 21 scale insect species, when taking into consideration the whole geographic area surveyed. Of all cases, 3.2% showed significant spatial separation in smaller geographic regions. However, no evidence for competition was found between species with overlapping distributions. In the case of introduced species, the role of past competition can also be excluded. Separation was thought to be determined by differences in ecological requirements. There is some probability of competition in the transitional zone (significant separation in 0.8% of cases), and somewhat more (2.4%) in the Southern zone. There was potential competition between species classified as Mediterranean and invader subguilds (7.1% of frequent species pairs), as well as between the Southern and invader (2.4% of frequent species pairs) subguilds. Its probability was very low between the species of the endemic (0.8% of frequent species pairs) and invader (1.6% of frequent species pairs) subguilds.  相似文献   

15.
    
Zusammenfassung Es wird über Laboratoriums-Versuche mit 3 verschiedenen Typen von Bacillus thuringiensis-Präparaten an Honigbienen berichtet: (a) mit dem Sporen- Endotoxin-Komplex, (b) mit vegetativen Zellen und (c) mit von diesen produziertem wasserlöslichem thermostabilem Exotoxin. Während Sporen-Endotoxin-Präparate (geprüft an 5 Varietäten) in den für die Bekämpfung von Lepidopteren-Raupen benutzten Dosierungen ungefährlich sind, wirken hohe Dosen toxisch, wenn sie im Futtersaft adulten Bienen appliziert werden. Ein durch vegetative Zellen bedingter nachteiliger Einfluß auf Bienen wurde nicht beobachtet. Das Exotoxin welches von bestimmten Varietäten (z.B. var. thuringiensis) in die Kulturflüssigkeit abgegeben wird, wirkt auf Bienen giftig, wenn es im Futtersaft und als Konzentrat verfüttert wird.
Summary In laboratory trials the effects of three types of preparations of Bacillus thuringiensis were tested on adult honey bees (Apis mellifera L.): (a) the spore-endotoxin-complex, (b) vegetative cells, and (c) the exotoxin. Though spore-endotoxin-preparations (of 5 varieties) were harmless to bees in dosage used for biological control, higher dosages applied in sugar solution were toxic. By using a medium concentration of vegetative cells no disease symptoms could be observed on bees. But the water-soluble thermostable factor, the so-called exotoxin, which is produced by the vegetative cells of several varieties (for example var. thuringiensis), was toxic to bees after feeding. The consequences of these observations are discussed.
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16.
Zusammenfassung Blutregen und Blutschnee sind zwei auffallende Naturerscheinungen, die in der Hauptsache durch Massenvorkommen von Aplanosporen der volvocalen Grünalgen Haematococcus pluvialis und Chlamydomonas nivalis verursacht werden. Die für die rote Farbe verantwortlichen Pigmente sind Keto-Carotinoide. Die Versuche zeigen, daß auch unter natürlichen Bedingungen für die Biosynthese dieser Polyene und für den gleichzeitig ablaufenden Abbau der Chlorophylle Stickstoffmangel der entscheidende Faktor ist.
Blood-rain and blood-snow: Nitrogen-deficient cells of Haematococcus pluvialis and Chlamydomonas nivalis
Summary The blood-rain and the blood-snow, two phenomena caused mainly by mass occurrence of aplanospores of the volvocalean green algae Haematococcus pluvialis and Chlamydomonas nivalis, have been studied under natural conditions. The red pigments belong to the keto-carotenoids. The experiments show that also in nature the biosynthesis of these polyenes and the parallel decomposition of the chlorophylls are caused by nitrogen deficiency.
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17.
Growth and oxygen uptake of potato callus is faster in an oxygen-enriched atmosphere (70% oxygen, v/v; oxygen-callus) than in air (20% oxygen, v/v; air-callus). Especially the non-mitochondrial, so-called residual respiration is increased in oxygen-callus. The capacities of the mitochondrial respiratory pathways (cytochrome pathway, Vcyt and alternative pathway, Valt) are also higher in this callus. In both callus types only a small part of the alternative pathway capacity is used in uninhibited respiration. The lower oxygen uptake of air-callus at normal air oxygen pressures is partially due to diffusional impedance. Measurement of the respiratory parameters of air-callus in oxygen-saturated medium leads to higher values than measurement in air-saturated medium, although these values are still lower than those of oxygen-callus.ATP-production was calculated from the oxygen-uptake data and compared with the dry weight production of the callus to give values of 10.0 and 10.8 g dry weight produced.-mol ATP-1, for air-callus and oxygen-callus respectively. As no harmful side-effects are observed, cultivation of callus under elevated oxygen pressures may be useful, when rapid callus-growth is necessary.Abbreviations AA antimycin A; A; - BHAM benzohydroxamate - DW dry weight - FW fresh weight - 8-OHQ 8-hydroxyquinolin - RC respiratory control - SHAM salicylhydroxamate  相似文献   

18.
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   

19.
Interleukin 2-dependent alloreactive cytotoxic T cell lines, with activity predominantly directed against the HLA-A2 antigen, have been generated in vitro by stimulating blood mononuclear cells from donors nonimmune to the Epstein-Barr (EB) virus with appropriate numbers of EB virus-transformed B cells from A2-homozygous individuals. Such effector cells were tested against a panel of EB virus-transformed target cell lines all expressing the serologically defined A2 antigen but typed into common A2 and variant A2 subgroups on the basis of their recognition by A2-restricted EB virus-specific cytotoxic T cells. Variant A2 responder cells cocultivated with common A2-bearing stimulators gave rise to effector T cell lines which recognized only the common A2-bearing subgroup of targets. By contrast, responder cells from A2-negative donors stimulated with common A2-bearing cells produced effector T cell lines in which the strong lysis of common A2-bearing targets was accompanied by a lower, but still significant, lysis directed against all targets within the variant A2 subgroup. In both cases, lysis of the target cells was blocked equally well by the anti-A2-specific monoclonal antibody MA2.1 as by the monoclonal antibody W6/32 specific for HLA-A, -B, and -C determinants. This suggests that HLA-A2 molecules possess at least two distinct sets of epitopes capable of inducing alloreactive T cell cytotoxicity: first, epitopes probably associated with T cell-restricting sites, which generate subgroup-specific responses, and second, epitopes shared by all A2 molecules, and perhaps associated with serologically defined sites, which generate pan A2 group-specific responses.Abbreviations used in this paper EB Epstein-Barr - IL-2 Interleukin 2 - UM unfractionated mononuclear - AET aminoethylisothiouroniumbromide hydrobromide  相似文献   

20.
E. F. Abel 《Oecologia》1970,4(2):133-142
Zusammenfassung Die Tentakel der Edelkoralle vermögen sich an den Spitzen bis über die dreifache Länge der Normtentakel fadenartig zu verlängern (Fadententakel). Diese Tentakelfäden wickeln sich bei Berührung eines Nahrungsobjekts korkzieherartig auf und nähern dieses durch Kontraktion der Mundöffnung.Damit koordiniert führen die zugehörigen Basalabschnitte (Normtentakel) durch S-förmige Biegungen und eventuelle Verkürzungen die Stelle der gereizten Tentakelfadens präzise zum Mund.Werden die Normtentakel allein gereizt, so antworten sie mit raschem Einschlag zur Mundöffnung. Bei gleichzeitiger Reaktion aller Tentakel wird dadurch eine Tentakel-Faust oder ein Fangkorb gebildet. Bei schwachen Reizen antwortet der Normtentakel anstelle der schlagenden Reaktionen mit langsamen Krümmungen, die das Objekt zur Mundöffnung dirigieren. Unabhängig von der Reaktionsart der Tentakeln wird die Beute vor der Aufnahme stets geprüft und häufig abgelehnt. Ist der Polyp in Freßstimmung, so wird die Nahrung rasch durch das glockenartig erweiterte Schlundrohr geschleust und verschwindet nach wenigen Minuten im Coelenteron.
The tentacle apparatus of the red coral (Corallium rubrum L.) and its role in feeding behaviour
Summary The tentacles of the octocoral Corallium rubrum may become extremely elongated (threadlike-tentacle) the apical part of the norm-tentacle becoming stretched more than three times as much as the base.The threadlike parts of the tentacles contract corcscrew-like when touched by food particles.The stimulated part of the tentacle is brought close to the mouth by coordinated movements of its basal portion. Very often both threadlike-tentacle and norm-tentacle shorten in order to carry the particle to the pharynx.When the norm-tentacles only are touched, they react with quick strokes towards the oral disc. This behaviour, when shown by all tentacles at the same time results in the formation of either a tentacle-fist or a basketlike structure. At slight irritations the norm-tentacle will respond with slow bending movements, which lead the particle towards the mouth. Independent of the type of tentacle reactions the prey is always checked before entering the pharynx, and very often refused.If the polyp decides to accept, food is transported quickly through the elongated pharynx and within a few minutes will have disappeared in the coelenteron.
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