bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE SIGNIFICANCE OF IONIC CONCENTRATIONS IN THE INTERNAL MEDIA OF ANIMALS
Authors: BURTON RICHARD F. 
Published: January 2008

Summary1. The electrical and ionic gradients across a cell membrane depend on its permeability properties, on the concentration and net valency of the organic constituents of the cytoplasm and on the critical energy barrier to the extrusion of sodium. Such considerations do not, however, explain the small extent to which the concentration of potassium varies in myoplasm which may, instead, be related to the effects of potassium on particular enzymes.2. The fact that the apparent optimum level of potassium cannot usually be maintained in animals in which the extracellular level of sodium is below about 140 mM may explain why so many non‐marine animals have internal media of about that concentration, for more concentrated body fluids would require more work for their regulation.3. In axoplasm, the concentration of potassium is more nearly proportional to the concentration of sodium in the internal medium and this may partly explain the general correlation between the extracellular levels of sodium and potassium.4. The relation between pH and temperature in poikilothermic vertebrates is such as to suggest that the prime function of acid‐base regulation is to control the ionization of imidazole groups.5. High tensions of carbon dioxide cannot be maintained in water‐breathing animals because of the high solubility of this gas in water as compared with oxygen. Bicarbonate levels are correspondingly low to give a suitable pH. Higher tensions are possible in air‐breathing animals, and also necessary if water and heat are to be conserved, but an uncertain upper limit is set by the need for oxygen. The associated higher levels of bicarbonate confer the advantage of better buffering.6. Calcium and bicarbonate levels are not obviously limited by the solubility of calcium carbonate and a more general limitation on the composition of body fluids seems to arise from the low solubilities of calcium phosphates.7. The pattern of ionic balance in vertebrate plasma, reflected in a nearly constant value to the molar ratio ([Ca] + 5 × 10‐‐4)/([K] +0.034 [Na]), may be explained in terms of the maintenance of a constant electrical gradient across certain areas of cell membrane, between the inner and outer double layers.8. The patterns of cation balance in the haemolymphs of molluscs, crustacea and insects are also reviewed, with emphasis on the correlations existing between the concentrations of different cations. An attempt is made to relate the correlations in the mollusca to the concentrations of cations at the surfaces of cells.
DEVELOPMENTAL BIOLOGY AND THE STUDY OF MALFORMATIONS
Authors: Hughes A. F. W. 
Published: January 2008

Summary1. The scientific approach to malformations began with experimental work on abnormal conditions of incubation in the chick.2. More precise experiments on causing abnormalities had a common origin with experimental embryology.3. Progress in experimental teratology during the last fifty years is reviewed in a commentary on the four principles formulated by Stockard in 1921.4. Some relationships are traced between the results of cytogenetical studies in man and in other organisms.5. An account is given of present knowledge concerning malformations of the neural tube originating either experimentally, spontaneously, or phenotypically.6. The teratological implications of some recent theories on the expression of the genotype are discussed, particularly in relation to problems of hormones as teratogens.7. Some account is given of the implication of carbohydrate metabolism and terato‐genesis.8. Teratogenesis is possibly related to cationic balance in early development.9. It is suggested that one factor retarding progress in the understanding of malformations is the tendency towards the development of teratology in an insufficiently close relationship with other branches of cell biology.
GENETIC CONTROL OF VERY EARLY MAMMALIAN DEVELOPMENT
Authors: MAGNUSON TERRY , EPSTEIN CHARLES J. 
Published: January 2008

SummaryThe overall picture of mammalian preimplantation development is one of complex but integrated molecular activity. As development progresses from the 1 cell stage, blastomeres acquire properties that differ from those of cells of previous stages and eventually differ from one another even at the same stage. The evidence concerning the role of the embryonic genome during this process can be summarized under two headings:(1) Expression of embryonic genome(a) Quantitative and qualitative changes in RNA and protein synthesis begin to occur soon after fertilization.(b) Changes in structural proteins (enzyme activities, transport systems and intercellular junctions) occur throughout early development.(c) Paternal gene products can be detected as early as the 2‐cell stage.(2) The need for expression of the embryonic genome(a) Inhibitors of RNA and protein synthesis result in abnormal and lethal development.(b) Several mutations (T/t, Ay, Os, c25H, Om, Ts) are lethal during early development.(c) Chromosomal imbalance (monsomy, haploidy, nullisomy) has adverse effects on early development.Even though studies in vitro on the inhibition of translation indicate that stable maternal messenger RNAs are present in the developing mouse embryo, the evidence outlined in this article strongly supports the belief that embryonic gene expression occurs very early in development (at least by the 2 cell stage) and that this expression is required for normal development.
PHORESY AS MIGRATION ‐ SOME FUNCTIONAL ASPECTS OF PHORESY IN MITES
Authors: BINNS E. S. 
Published: January 2008

SummaryI. The dispersive role of mite phoresy, which has merely been presumed, is presented in the light of modern theories of migration with the aim of its characterization behaviourally, ecologically and physiologically.II. Data on phoresy accords well with modern, behavioural definitions of migration, as a phase of the depression of growth‐promoting functions, during which the phoretic mite is transported while it shows a special readiness for being moved.III. Thus, modern definitions of migration encompass ‘passive’ movements which, none the less, involve active phases of seeking out of the host.IV. An examination of mite loads suggests that phoresy is most effective where the host gathers within the range of the mite; hence the association of phoresy with micro‐habitats between which the mite requires to be carried. Monocultural plant‐stands and ecological climaxes are not characterized by phoretic associations.V. The role of phoretic mites in colonization is clarified, in that phoretic migration is associated with sub‐climactic communities. Thus, phoresy is invited where habitats are discrete and temporary, in which case it is manifest, as typical of migration, as a means of colonizing and exploiting irregularly changing habitats byr‐selected, pre‐reproductive individuals.VI. Waiting‐stages, marked by the depression of growth‐promoting functions, occur within the life‐cycle of the phoretic mite. The ‘hypopus facies' characterize the typical phoretic stage, whose association with the host is an adaptation for survival in extreme environments.VII. Attachment pattern is a function of specificity towards the host. Structural and behavioural adaptations for attachment are developed and some sensory mechanisms have been shown, as have some physiological relationships with changes in the substrate; these changes also affect detachment.VIII. That phoresy is not caused by unfavourable conditions but is related to those that allow optimum dispersal is supported by sound evidence.IX. Physiologically, waiting stages have analogies with diapause which, together with migration, have been characterized by a temporary failure of the migrant to respond, by further growth and development, to the conditions that will eventually promote these processes.X. With phoresy are contrasted relations, between mite and insect, where the association is assured and more or less permanent.XI. The study of phoresy is very fragmented. However, a case has now been made for putting the dispersive role of phoresy beyond presumption, so that phoretic associations can clearly be fitted into modern treatments of migration.
COEFFICIENTS OF ASSOCIATION AND SIMILARITY, BASED ON BINARY (PRESENCE‐ABSENCE) DATA: AN EVALUATION
Authors: HUBÁLEK ZDENEK 
Published: January 2008

SummaryForty‐three association (similarity) coefficients were collected and evaluated in this survey. Some of them are synonyms or direct correlates with earlier described indices (A8, A9, A12, A31, A33), others are mere transforms from one range of values to another (A10, A24, A33). Several coefficients are incompatible with suggested admissibility conditions of the minimum‐maximum value (A13, A16, A27, A28, A29, A31), symmetry (A1, A2, A13, A16, A26), discrimination between positive and negative association (A27, A28, A31) or monotonicity with (χ2) (A19, to A24); A17 yields very low and erratic values.As a result, 23 coefficients were excluded and the remaining 20 measures were subjected to an empirical trial on interspecific association data among fungi of the genus Chaetomium, with the use of a cluster analysis. The classification produced five main clusters of related coefficients, with several subgroups. It was then demonstrated that representative indices from different clusters yield different dendrograms of interspecific association among Chaetomium, and A34, A14, possibly also A36 and A40 seemed to be less sensible. A set of measures that generally work well (at least in the interspecific association) comprises A4 (Jaccard), A4 (Dice‐Sφrensen), A7 (Kulczyński), A11 (Driver‐Kroeber‐Ochiai) and, with some reservation A30 (Pearson tetrachoric) and A32 (Baroni‐Urbani‐Buser). For some purposes, however, other ‘admissible’ coefficients would be more optimal, and the choice of a measure should be related to the nature of the data. It is tentatively suggested that three or so alternative coefficients be used and the results compared on the same data basis; moreover, significance tests on association should be carried out whenever possible.
Bacterial Blight of Cotton
Authors: Innes N. L. 
Published: January 2008

Summary1. Bacterial blight of cotton is potentially one of the most damaging diseases of cotton.2. Its symptoms and adverse effect on yield are described.3. Control measures include: (i) cultural techniques of crop sanitation, and the destruction of crop residues, as well as close seasons and crop rotation; (ii) chemical seed treatments and foliar sprays; (iii) the breeding of resistant varieties.4. Techniques are described for the breeding of resistant varieties, and sources of useful genetic plant resistance identified.5. The complex nature of the interactions between host genetic resistance, variation in the pathogen and environment is emphasized.6. Successful resistance‐breeding programmes in Africa and the USA are reviewed, and attention is drawn to the pressing need for resistant varieties in India and Pakistan.7. Continued success in the control of bacterial blight will require integrated programmes that include cultural methods, the use of chemicals (particularly as seed treatments) and the cultivation of resistant varieties with durable resistance.
THE FUSION OF SEXUAL NUCLEI
Authors: Szabo Stephen P. , O'Day Danton H. 
Published: January 2008

SummaryA classification scheme is proposed for the types of sexual nuclear fusion that occur in eukaryotes. The two main classes are envelope fusion and envelope vesiculation and each is further divided into subclasses. The formation of sexual nuclei (pronuclei) has been detailed in representatives from various phyla, but is best understood in animals, in which the development of male and female pronuclei differs in some respects. The only characterized cytoplasmic mediator of pronuclear movement are microtubules. Groups of eukaryotes can be classified according to the type of nuclear fusion they reveal. Envelope fusion occurs in animals whose eggs are fertilized at the pronuclear stage, and in all plants, fungi, protozoa and algae studied to date. Ultrastructural details of envelope fusion have shown variations that are classified in our scheme as direct and indirect, the latter being restricted to the plant kingdom. Envelope vesiculation only occurs in animals, in which it is the most common means of nuclear fusion. Four subclasses can be defined according to the timing of the vesiculation of the nuclear envelopes, and the extent of envelope surface projections prior to fusion. The amount of work reported on the controlling mechanisms of nuclear fusion has been limited, but some evidence of genetic control has been provided, particularly in fungi. Evidence is presented to indicate that the control of the fusion competence of nuclei is a negative one. This review of the information available on nuclear fusion points out the need for extensive future comparative studies if this important process is to be better understood.
BODY FAT, PUBERTY AND FERTILITY
Authors: FRISCH ROSE E. 
Published: January 2008

Summary1. The high percentage of fat, about 26–28% in the mature human female, may influence reproductive ability directly through two mechanisms: (a) fat converts androgens to oestrogens; (b) relative fatness influences the direction of metabolism of oestrogen to the most potent or least potent forms. The relative degree of fatness thus is directly related to both the quantity of circulating oestrogen and the biological effectiveness of the oestrogen. This is a neat mechanism for relating rates of growth, nutrition and energy outputs to the energy requirements for reproduction. Fat is the most labile body tissue; it therefore reflects environmental changes more rapidly than other tissues of the body.2. The slow maturation of the hypothalamus and pituitary up to menarche, or first oestrus, is accompanied by a slow maturation of the body, which changes not only in size but in the relative proportion of bone, muscle, and fat. Evidence is presented that a particular threshold ratio of fat to lean mass is normally necessary for puberty and the maintenance of female reproductive ability in the human and in the rat. The synchronizing mechanisms may be metabolic, relating food intake to core temperature and/or fat storage.3. Undernutrition and weight loss in the range of 10–15 % of normal weight for height delays menarche and causes amenorrhoea. Ballet dancers and athletes also have delayed menarche and amenorrhoea. The cessation of reproduction in both groups can be considered adaptive. Refeeding and/or cessation of intense activity results in the initiation or resumption of menstrual cycles after varying periods of time. A necessary threshold weight for height can be predicted from a fatness index.4. Differences in the natural fertility of historical and contemporary populations may be explained by a direct effect of food intake and energy outputs on fecundity.5. The late maturing fat ‐ ‘sex fat’ ‐ may have a special role in reproduction.
CELL SELECTION IN DEVELOPMENT
Authors: MICHAELSON JAMES 
Published: January 2008

SummaryCell selection is recognized to be the principal mechanism in the generation of the immune response. The role of cell selection in other developmental systems is considered here, with emphasis on the morphogenesis of the vertebrate limb, the formation of pigment pattern in the pelt of mammals and the changes that occur in the human erythrocyte at the time of birth.
STRUCTURAL AND ULTRASTRUCTURAL FEATURES OF CORTICAL CELLS IN MOTOR ORGANS OF SENSITIVE PLANTS
Authors: FLEURAT‐LESSARD PIERRETTE 
Published: January 2008

Summary(1) The movements are only expressed in motor cells, regardless of the nature of the stimulation or its point of application. Therefore, these cells have structures capable of traducing the different stimulation‐induced messages which are received in parts incapable of movement.(2) K+, Cl‐ and Ca2+ are the major ions. Their fluxes have been followed during nyctinastic movements as well as during stimuli‐induced movements. At the moment, the location and the role of these ions are being studied.(3) The movement results from the integrated activity of all (n) motor cells in the pulvini (i.e. n > 350 × 103 in primary pulvini 3 mm long and 1·9 mm thick).(4) The motor cell is a full‐grown cell whose osmotic activity induces turgor variations allowing foliar movements.(5) The motor cell is a highly differentiated cell, which, up to now, has never been able to dedifferentiate in order to produce callus.(6) The motor cell has original features in its apoplastic compartment (large meatuses, wall foldings, large periplasm with membranes) and in its symplastic compartment (double vacuolar apparatus, morphological polarity given by the tannin vacuole location near the nucleus, abundant mitochondria).(7) Its cytoskeleton includes microtubules, cytoplasmic and vacuolar fibrils (in particular in the tannin vacuole), and a wall with special properties.(8) The motor cell is supposed to contain contractile proteins, whose nature and location are being investigated.(9) The shape change of the motor cell is obvious after pulvinar bending. This change is probably associated with a volume change in several intracellular compartments (vacuole, mitochondria, vesicles).(10) At the cellular and subcellular level the same general features are observed in motor cells of non‐seismonastic and of seismonastic species. Probably, functional differences depend upon differences occurring at the molecular level.(11) The motor cell is an interesting model for the study of the osmoregulation mechanism in plant cells, to test the effect of toxic products, in particular to find their optimal efficiency in the circadian cycle.
THE FUNCTIONAL ORGANIZATION OF FILTRATION NEPHRIDIA
Authors: RUPPERT EDWARD E. , SMITH PETER R. 
Published: January 2008

Summary(1) Based on the classical studies of Goodrich, protonephridia are believed to be phylogenetic antecedents of metanephridia. It is argued here that the primary factor determining the type of nephridium expressed is body size rather than phylogenetic status.(2) The proposed model defines a nephridium functionally and predicts two general configurations for filtration nephridia in animals.(3) Application of the model to metanephridial and protonephridial systems indicates differences in the sites of ultrafiltration and mechanisms of pressure generation.(4) Metanephridial systems function by muscle‐mediated filtration of vascular fluid into a coelomic space before modification by an excretory duct.(5) Protonephridial systems function by cilia‐mediated filtration of extracellular fluid into the lumen of a protonephridial terminal cell before modification in an adjoining duct.(6) The model predicts a correlation between animals with blood vessels and metanephridia, and animals without blood vessels and protonephridia. The correlation is shown to be nearly perfect.(7) Exceptions to the model are discussed.(8) Original experimental evidence is given for the permeability of the protonephridial terminal cell to iron dextran and its reabsorption by the protonephridial duct in the polychaete, Glycera dibranchiata.(9) Experimental data for proto‐ and metanephridial systems are summarized and shown to support the proposed model.(10) The ultrastructure of the exceptional amphioxus ‘protonephridium’ is reviewed and original data are presented. Its organization is structurally and perhaps functionally intermediate between proto‐ and metanephridial systems.(11) An original ultrastructural comparison is made of monociliated nitration cells in a size range of larval invertebrates from five phyla. Filtration cells that are structurally intermediate between protonephridial solenocytes and metanephridial podocytes are noted in larvae intermediate in body size between the two extremes. The comparative data suggest that (i) podocytes and solenocytes are homologous cells and (ii) that body size is correlated with which of the two designs is expressed.(12) The fates of larval podocytes are followed through metamorphosis in three species. The results confirm the equivalence of podocytes and solenocytes as suggested by the comparative analysis. They further indicate that which morph is expressed is a function of body design factors discussed in the model.(13) Protonephridia are believed to be primitive to metanephridia because they occur in presumably primitive animals and in ontogenetic stages of many animals with metanephridia as adults. It is suggested here that the distribution of protonephridia is related to small body size and the lack of blood vessels, regardless of phylogenetic status. The occurrence of protonephridia in the larvae of species with metanephridia as adults is explained similarly as a function of the small larval size and lack of blood vessels.
HISTOLOGICAL STAINING OF LIPIDS FOR THE LIGHT AND ELECTRON MICROSCOPE
Authors: WIGGLESWORTH V. B. 
Published: January 2008

Summary1. It is generally agreed that the blackening of osmium tetroxide by unsaturated lipid is too unpredictable to demonstrate lipid in tissues.2. At neutral pH osmium tetroxide combines with the double bonds in the lipoproteins of cellular membranes (mitochondria, etc.) and the deep colour reaction of ethyl gallate with this osmium provides good staining of lipid for the light microscope.3. Osmium taken up by tissue proteins at neutral pH is only a small fraction of that taken up by the lipid. (After acid fixatives osmium tetroxide is a general protein stain.)4. The uptake of Sudan black B by partition from dilute solution is a specific test for lipid, but in normally fixed tissue most of the structural lipid is ‘bound’ and is not accessible to the dye.5. Cautious treatment of fixed tissue with dilute sodium hypochlorite will unmask this lipid for viewing by the light microscope.6. Direct fixation with neutral osmium tetroxide is an effective method for visualizing lipid for the electron microscope (as in the ethyl gallate method for the light microscope). But the poor penetration of osmium limits its use in this way.7. After formol/glutaraldehyde fixation much of the lipid in the tissues is ‘bound’ and does not take up osmium. It can be unmasked by a saturated aqueous solution of thymol.8. The unmasked lipid can then be rendered more osmiophil by partition in a solution of the highly unsaturated terpene farnesol, thus increasing the uptake of osmium in a renewed application.9. Some of the novel observations on tissue lipids made by these methods are reviewed.