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1.
Edward O. Wilson’s recent decision to abandon kin selection theory has sent shockwaves throughout the biological sciences. Over the past two years, more than a hundred biologists have signed letters protesting his reversal. Making sense of Wilson’s decision and the controversy it has spawned requires familiarity with the historical record. This entails not only examining the conditions under which kin selection theory first emerged, but also the organicist tradition against which it rebelled. In similar fashion, one must not only examine Wilson’s long career, but also those thinkers who influenced him most, especially his intellectual grandfather, William Morton Wheeler (1865–1937). Wilson belongs to a long line of organicists, biologists whose research highlighted integration and coordination, many of whom struggled over the exact same biological riddles that have long defined Wilson’s career. Drawing inspiration (and sometimes ideas) from these intellectual forebears, Wilson is confident that he has finally identified the origin of the social impulse.  相似文献   

2.
This article analyses William J. Wilson’s use of the concept of social isolation in studying the urban poor. It traces the origins of Wilson’s use of the concept in human ecology, focusing upon critical aspects of the ‘socially isolated’ city and its influence upon ethnographies of the urban poor. His particular focus is upon the interaction of the poor with the mainstream. While Wilson places considerable emphasis upon the role of the state, those appropriating his concept have not adequately incorporated government institutions and discourse into their analyses of culture and practice.  相似文献   

3.
Perhaps no other period has contributed more to our knowledge of the cell than the period 1875-1895. During these years most fundamental cytological phenomena were seen and described. Mitosis, maturation and fertilization, the great cornerstones of cytology, were firmly laid by the remarkable researches of Flemming, Strasburger, Van Beneden, Oscar and Richard Hertwig, Boveri and many others. Upon these researches experimental cytology developed and the significance of the morphological phenomena to inheritance and development was pointed out by such masters as W. Roux, Weismann, O. Hertwig, Boveri and E. B. Wilson.  相似文献   

4.
Perhaps no other period has contributed more to our knowledge of the cell than the period 1875-1895. During these years most fundamental cytological phenomena were seen and described. Mitosis, maturation and fertilization, the great cornerstones of cytology, were firmly laid by the remarkable researches of Flemming, Strasburger, Van Beneden, Oscar and Richard Hertwig, Boveri and many others. Upon these researches experimental cytology developed and the significance of the morphological phenomena to inheritance and development was pointed out by such masters as W. Roux, Weismann, O. Hertwig, Boveri and E. B. Wilson.  相似文献   

5.
A return to Claude Bernard's original use of the concept of 'determinism' displays the fact that natural laws were presumed to rule over all natural processes. In a more restricted sense, the term boiled down to a mere presupposition of constant determinant causes for those processes, leaving aside any particular ontological principle, even stochastic. The history of the cell theory until around 1900 was dominated by a twofold conception of determinant causes. Along a reductionist trend, cells' structures and processes were supposed to be accounted for through their analysis into detailed partial mechanisms. But a more holistic approach tended to subsume those analytic means and the mechanism involved under a program of global functional determinations. When mitotic and meiotic sequences in nuclear replication were being unveiled and that neo-Mendelian genetics was being grafted onto cytology and embryology, a conception of strict determinism at the nuclear level, principally represented by Wilhelm Roux and August Weismann, would seem to rule unilaterally over the mosaic interpretation of the cleavage of blastomeres. But, as shown by E.B. Wilson, in developmental processes there occur contingent outcomes of cell division which observations and experiments reveal. This induces the need to admit 'epigenetic' determinants and relativize the presumed 'preformation' of thedevelopmental phases by making room for an emergent order which the accidental circumstances of gene replication would trigger?on.  相似文献   

6.
In his comprehensive Oeuvre, Galen of Pergamon, who interpreted and perfected Hippocratic medicine, made many times and in various contexts mention of the intermittent fevers, among which malaria undoubtedly held a prominent position. The following article gives an outline of Galen's theoretical concept of this infectious disease, which was of utmost importance for the history of Italy. Galen describes three different types of intermittent fevers, of which, according to his theory of humoural pathology, each one is caused by a special humour with its respective qualities. Thus the quotidian fever is caused by phlegm, the tertian fever by the yellow bile and the quartan fever by the black bile. Apart from the three basic types of fever Galen describes a number of other mixed forms which can either be developed out of identical types or out of different ones. A mixture of a special kind is febris semitertiana: a continuous quotidian is accompanied by an intermittent tertian. It is the worst and most dangerous of these fevers. On the whole Galen's theory of malaria is a paradigm for his forming the reality of diseases on the basis of his pre-knowledge of humoural pathology into a closed system of theory.  相似文献   

7.
Neurodegenerative disease is a brain disorder caused by the loss of structure and function of neurons that lowers the quality of human life. Apart from the limited potential for endogenous regeneration, stem cell-based therapies hold considerable promise for maintaining homeostatic tissue regeneration and enhancing plasticity. Despite many studies, there remains insufficient evidence for stem cell tracing and its correlation with endogenous neural cells in brain tissue with three-dimensional structures. Recent advancements in tissue optical clearing techniques have been developed to overcome the existing shortcomings of cross-sectional tissue analysis in thick and complex tissues. This review focuses on recent progress of stem cell treatments to improve neurodegenerative disease, and introduces tissue optical clearing techniques that can implement a three-dimensional image as a proof of concept. This review provides a more comprehensive understanding of stem cell tracing that will play an important role in evaluating therapeutic efficacy and cellular interrelationship for regeneration in neurodegenerative diseases.  相似文献   

8.
Aristotle’s theory of spontaneous generation offers many puzzles to those who wish to understand his theory both within the context of his biology and within the context of his more general philosophy of nature. In this paper, I approach the difficult and vague elements of Aristotle’s account of spontaneous generation not as weaknesses, but as opportunities for an interesting glimpse into the thought of an early scientist struggling to reconcile evidence and theory. The paper has two goals: (1) to give as charitable and full an account as possible of what Aristotle’s theory of spontaneous generation was, and to examine some of its consequences; and (2) to reflect on Aristotle as a scientist, and what his comments reveal about how he approached a difficult problem. In particular, I propose that the well-recognized problem of the incompatibility between Aristotle’s concept of spontaneity and his theory of spontaneous generation presents an opportunity for insight into his scientific methodology when approaching ill-understood phenomena.  相似文献   

9.
The cell theory—the thesis that all life is made up of one or more cells, the fundamental structural and physiological unit—is one of the most celebrated achievements of modern biological science. And yet from its very inception in the nineteenth century it has faced repeated criticism from some biologists. Why do some continue to criticize the cell theory, and how has it managed nevertheless to keep burying its undertakers? The answers to these questions reveal the complex nature of the cell theory and the cell concept on which it is based. Like other scientific ‘laws’, the assertion that all living things are made of cells purchases its universality at the expense of abstraction. If, however, this law is regarded merely as a widely applicable empirical generalization with notable exceptions, it still remains too important to discard. Debate about whether the cell or the organism standpoint provides the more correct account of anatomical, physiological, and developmental facts illustrates the tension between our attempts to express the truth about reality in conceptual terms conducive to a unified human understanding.  相似文献   

10.
Direct in vivo visualization, in full atomic detail, of the microbial cell wall and its stress-bearing structural architecture remains one of the prime challenges in microbiology. In the meantime, molecular modeling can provide a framework for explaining and predicting mechanisms involved in morphogenesis, bacterial cell growth and cell division, during which the wall and its major structural component--murein--have to protect the cell from osmotic pressure and multiple tensile forces. Here, we illustrate why the scaffold concept of murein architecture provides a more comprehensive representation of bacterial cell wall physiology than previous models.  相似文献   

11.
Summary In this paper we analyze Carl Gegenbaur’s conception of the relationship between embryology (“Ontogenie”) and comparative anatomy and his related ideas about homology. We argue that Gegenbaur’s conviction of the primacy of comparative anatomy and his careful consideration of caenogenesis led him to a more balanced view about the relationship between ontogeny and phylogeny than his good friend Ernst Haeckel. We also argue that Gegenbaur’s ideas about the centrality of comparative anatomy and his definitions of homology actually laid the conceptual foundations for Hans Spemann’s (1915) later analysis of homology. We also analyze Gegenbaur’s reception in the United States and how the discussions between E.B. Wilson and Edwin Conklin about the role of the “embryological criterion of homology” and the latter’s argument for an even earlier concept of cellular homology reflect the recurring theme of preformism in ontogeny, a theme that finds its modern equivalent in various genetic definitions of homology, only recently challenged by the emerging synthesis of evolutionary developmental biology. Finally, we conclude that Gegenbaur’s own careful methodological principles can serve as an important model for proponents of present day “evo-devo”, especially with respect to the integration of ontogeny with phylogeny embedded in comparative anatomy.  相似文献   

12.
A mathematical analysis is developed from the concepts of the molecular theory of cell survival to explain the cytotoxic action of a platinum complex on CHO cells and its synergistic interaction with radiation. In the analysis, it is assumed that both inter- and intra-strand cross-links induced by the Pt complex in the DNA contribute to cell killing and that the synergistic effect arises from the interaction between an intra-strand cross-link and a radiation-induced single-strand break on complementary strands of the DNA. The analysis is shown to be compatible with experimental results. Further, a mechanistic model is developed in an attempt to explain in more detail the processes which appear to be involved in the expression of the cytological damage.  相似文献   

13.
14.
Li H  Chen XY  Kong QY  Liu J 《Cell research》2002,12(2):117-121
The co-existence of multiple cell components in tissue samples is the main obstacle for precise molecular evaluation on defined cell types. Based on morphological examination, we developed an efficient approach for paralleled RNA and protein isolations from an identical histological region in frozen tissue section. The RNA and protein samples prepared were sufficient for RT-PCR and Western blot analyses, and the results obtained were well coincident each other as well as with the corresponding parameters revealed from immunohistochemical examinations. By this way, the sampling problem caused by cell-cross contamination can be largely avoided, committing the experimental data more specific to a denned cell type. These novel methods thus allow us to use single tissue block for a comprehensive study by integration of conventional cytological evaluations with nucleic acid and protein analyses.  相似文献   

15.
The cell block (CB) is a routine procedure in cytopathology that has gained importance because of its pivotal role in diagnosis and ancillary studies. There is no precise review in the published literature that deals with the various methods of preparation of CB, its utility in diagnosis, immunocytochemistry (ICC) or molecular testing, and its drawbacks. An extensive literature search on CB in cytology using internet search engines was performed for this review employing the following keywords: cell block, cytoblock, cytology, cytopathology, methods, preparation, fixatives, diagnostic yield, ancillary and molecular studies. Ever since its introduction more than a century ago, the CB technique has undergone numerous modifications to improve the quality of the procedure; however, the overall principle remains the same in each method. CBs can be prepared from virtually all varieties of cytological samples. In today's era of personalized medicine, cytological specimens, including CBs, augment the utility of cytological samples in analysing the molecular alterations as effectively as surgical biopsies or resection specimens. With the availability of molecular targeted therapy for many cancers, a large number of recent studies have used cytological material or CBs for molecular characterization. The various techniques of CB preparation with different fixatives, their advantages and limitations, and issues of diagnostic yield are discussed in this review.  相似文献   

16.
Summary Certain aspects of cellular behaviour in relation to growth and development of plants can be understood in terms of the cell body concept proposed by Daniel Mazia in 1993. During the interphase of the mitotic cell cycle, the plant cell body is held to consist of a nucleus and a perinuclear microtubule-organizing centre from which microtubules radiate into the cytoplasm. During mitosis and cytokinesis in meristematic cells, and also during the period of growth in post-mitotic cells immediately beyond the meristem, the plant cell body undergoes various characteristic morphological transformations, many of which are proposed as being related to changing structural connections with the actin-based component of the cytoskeleton and with specialized, plasma-membrane-associated sites at the cell periphery. In post-mitotic cells, these transformations of the plant cell body coincide with, and probably provide conditions for, the various pathways of development which such cells follow. They are also responsible, for the acquisition of new cellular polarities. Events in which the plant cell body participates include the formation of a mitotic spindle, phragmoplast, and new cell division wall, the rearrangement of a diffuse type of cell wall growth into tip growth (as occurs, e.g., during the initiation and subsequent development of root hairs), and the growth and division that occurs in reactivated vacuolate cells. If more evidence can be marshalled in support of the existence and properties of the plant cell body, then this concept could prove useful in interpreting the cytological bases of a range of developmental events in plants.Abbreviations CMT cortical microtubule - EMT endoplasmic microtubule - ER endoplasmic reticulum - MF microfilament - MT microtubule - MTOC microtubule-organizing centre - PPB preprophase band (of microtubules) - QC quiescent centre - VSC vesicle supply centre  相似文献   

17.
Genetics of sex determination in man and mouse   总被引:3,自引:0,他引:3  
The cytological evidence has revealed a visible mechanical basis for the production of males and females in equal numbers and irrespective of external conditions (Wilson, 1909).  相似文献   

18.
L Dintenfass 《Biorheology》1990,27(2):149-161
Although the question whether the red cell is fluid or solid has been discussed since 17th century, it was the author's measurement of the relative viscosity of blood in 1960's that supplied the first direct evidence that the red cell interior is fluid. Furthermore, through his application of the equations of Taylor and, later, Oldroyd, to this problem, it became evident that, for the red cell to exhibit fluid-drop-like behavior, the membrane must also be fluid. This led to his concept of the red cell membrane as a complex two-phase structure (lipoprotein micelles and two-dimensional protein networks) which was similar to the one accepted nearly a decade later. The requirements of the theory of ideal emulsions that the shear stress be transmitted into the cell interior via low viscosity membrane, are met in the later work of other investigators using the concept of a tank-treading membrane having viscoelastic properties. This paper reviews the original work of the author which led to the development of an equation for the relative viscosity of blood as a function of volume concentration, C: nr = (1 - TkC)-2.5, valid at shear rates above 180 sec-1, in which T is the Taylor factor which gives a measure of fluidity of the red cell, and k is a plasma trapping factor. Both T and k increase with increasing rigidity of the red cell. Finally, the effect of the membrane viewed as a complex two-phase fluid, on the rheology of the red cell is discussed.  相似文献   

19.
Donald Hebb’s concept of cell assemblies is a physiology-based idea for a distributed neural representation of behaviorally relevant objects, concepts, or constellations. In the late 70s Valentino Braitenberg started the endeavor to spell out the hypothesis that the cerebral cortex is the structure where cell assemblies are formed, maintained and used, in terms of neuroanatomy (which was his main concern) and also neurophysiology. This endeavor has been carried on over the last 30 years corroborating most of his findings and interpretations. This paper summarizes the present state of cell assembly theory, realized in a network of associative memories, and of the anatomical evidence for its location in the cerebral cortex.  相似文献   

20.
Malaria parasites enter red cells in a multi-step process involving attachment, membrane deformation, invagination and encapsulation. The molecular basis of red cell rigidity is examined by Geoff Pasvol and lain Wilson, and they discuss its effect on the efficiency of invasion by various Plasmodium spp.  相似文献   

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