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1.
Paraphysomonas faveolata sp. nov. (Chrysophyceae), a fourth marine species with meshwork body-scales
Paraphysomonas faveolata sp. nov., the eighth described species of this genus of colourless chrysophycean flagellates, has heterokont flagellation, parabasal nucleus and silicified body-scales. It is the fourth known species with meshwork scales, these being of two types: flat “cobweb” scales and scales with a planar “honeycombed” extension arising from a “cobweb” base. The organism is compared with the other species of the genus and the case considered for placing forms with meshwork scales in a new genus, separate from forms with spined scales. This step is not taken and the taxonomic status of the genus is discussed in relation to the Ochromonadaceae and other genera of the Synuraceae. 相似文献
2.
Impact of the invasion of the imported fire ant 总被引:1,自引:0,他引:1
S. Bradleigh Vinson 《Insect Science》2013,20(4):439-455
The impact of the imported fire ant (IFA) is complex, in large part, because several very different species of “Fire Ants” have invaded and one of these has two forms, all of which are hard to separate by the public, as well as, some investigators not focused on the ant. Each of these different “IFA” species and forms differ in their impact. Further, these ants impact a number of “things” ranging from the environment and wildlife (plants and animals) as well as people, their environment and infrastructure. In addition, they can not only lead to death of living things (including people), but they can destroy many aspects of our environment and infrastructure at the cost of millions of dollars. But there are some beneficial aspects and some people can make many thousands of dollars due to their presence. This is an attempt to look at these issues. 相似文献
3.
A new term, “trophon”, has been introduced for the feeding and sexually propagating unit in the stolonate ctenostomes; the “stolon” and the “trophon” represent “sukzooids”, because they are homologous only to parts of the autozooids in the uniserially arranged ctenostomes. – The ontogeny of the muscles, especially the parietal muscles, has been studied in 17 species of ctenostomatous bryozoans belonging to different sub-groups of this order; the main effort was directed toward the details of the differentiations in living animals (14 of the investigated species). In various species of the Ctenostomata two separate sets of parietal muscles develop – probably as a consequence of the elongation of the cystid; the functional parietal muscles in the trophons of the stolonial forms are homologous to the secondary parietal muscles found in several uniserial ctenostomes. Contrary to the supposition by Soule (1954) in the different families of the serially arranged forms the muscles appear in different sequences during the development of the zooid and partly have different ontogenetical fates. Neither the “Carnosa” nor the “Paludicellea” (s. 1.) nor the “Stolonifera” can be maintained as taxa with the argument of a similar ontogeny of the muscles. A detailed comparison regarding the fate of the parietal muscles (and the polypide anlage) showed similarities between certain of the uniserial to either some of the stolonial, the sheet like, or the cystid-fusing forms suggesting a separate evolutionary origin of the advanced forms in those groups of the serially growing forms. – A new family, Pottsiellidae fam. nov., has been introduced and defined. 相似文献
4.
Two forms of the equation for expression of the rate constant for electron transfer through a Marcus-type treatment are discussed. In the first (exergonic) form, the Arrhenius exponential term was replaced by its classical Marcus term; in the second (endergonic) form, the forward rate constant was replaced by the reverse rate constant (the forward rate constant in the exergonic direction), which was expanded to an equivalent Marcus term and multiplied by the equilibrium constant. When the classical Marcus treatment was used, these two forms of the rate equation give identical curves relating the logarithm of the rate constant to the driving force. The Marcus term for the relation between activation free-energy, DeltaG#, reorganization energy, lambda, and driving force, DeltaG(o), derived from parabolas for the reactant and product states, was identical when starting from exergonic or endergonic parabolas. Moser and colleagues introduced a quantum mechanical correction factor to the Marcus term in order to fit experimental data. When the same correction factor was applied in the treatment for the endergonic direction by Page and colleagues, a different curve was obtained from that found with the exergonic form. We show that the difference resulted from an algebraic error in development of the endergonic equation. 相似文献
5.
J J de Pont J H Vreeswijk H G Swarts S L Bonting 《Archives internationales de physiologie et de biochimie》1977,85(2):351-366
1. The relative permeabilities for sodium, potassium and chloride in guinea pig mammary gland slices are determined by means of ion flux studies with radioisotopes. 2. Assuming that there are no significant electrogenic potential components, we calculate permeability ratios PNa/PK = 0.97 and Pc1/PK = 1.25. 3. Substitution of these values in the Goldman equation yields membrane potentials of--15 mV before and--13 mV after ouabain treatment. 4. This small change in membrane potential explains the absence of a significant change in chloride content upon ouabain application, which leads to large changes in intracellular sodium and potassium concentrations. 相似文献
6.
O. Yagci 《Ecological Engineering》2010,36(1):36-46
Today, natural rivers are increasingly fragmented by human-made obstacles such as dams. Due to these structures fish populations in natural rivers rapidly diminish. In this context, fishways are a useful hydraulic structure in the creation of ecosystem for fish migration. Three dimensional mean flow and turbulence structure of pool-weir fishways were experimentally explored. During the experiments, three different notch sizes were applied while the size of the orifice was kept constant. Two acoustic Doppler velocimeters were employed throughout the velocity measurements. Three-dimensional mean velocity and normalized turbulent kinetic energy patterns in the pool were experimentally analyzed considering the swimming ability of different fish species to check whether the given design conditions provide suitable flow patterns. Based on the data, a linear relationship between the parameters “the discharge” and “the average depth in a pool” was generated. An equation was derived which gives the “energy dissipation rate per unit pool volume” in terms of the parameters “geometrical characteristics of the fishway”, “head difference between pools”, “slope”, and “acceleration due to gravity”. The discharge ratios between “flow through orifice” and “flow over notch” were expressed based on the data. 相似文献
7.
Boris I. Bespalov 《Journal of Russian & East European Psychology》2013,51(5-6):13-44
Based on an analysis of L.S. Vygotsky's concepts of “units” and “elements” of psychological systems, this article highlights five of their attributes. It shows that these attributes are logically symmetrical, since in their wording they can be converted into one another by negation or by replacing some words with their opposites. This suggests that the concepts of the “unit” and “element” of a system are different poles of one theoretical construct of the activity of human psychology. Thus methods for the study of psychological systems by breaking them down into elements or by separating them into units can be seen as complementary. The article describes differences among the concepts of “unit,” “minimal unit,” and “cell” of a psychological system. It reviews several problems that are solvable using the “method of units,” as well as some concepts of the theory of psychological systems that are understood as holistic, conceptual, and active processes and/or results of human interaction with the world. Among the examples of such systems are “systems of psychological functions” (according to Vygotsky), as well as separate activities (according to A.N. Leontiev), human actions and operations (interactions with the world on the level of objects and mental or physical means). The “component” of a psychological system is defined as any “something” that in some sense belongs to or is included in human interaction with the world. A component that belongs to the system is called an “element” of it, but a component that is included in the functioning and development of the system is called a “part” of it. The article presents the mathematical and psychological foundation of these definitions. It identifies and discusses the substantial (independently existing) components of psychological systems and their attributes (properties and conditions). It describes the relationships between them using the bipolar theoretical constructs “part-element” and “substantial-attributive” component of a system. 相似文献
8.
《Journal of insect physiology》1986,32(3):199-206
The effect of photoperiod on the calling behaviour of Pseudaletia unipuncta virgin females was examined under five different photoperiodic regimes at 25°C, 65% r.h. The age at which females called for the first time following emergence varied with photoperiod; generally calling was later under long-scotophase conditions. However under a 6 h scotophase there was also a delay in calling and >63% of the females tested never called. There was a considerable variability in the daily calling patterns between the different photoperiods, and the mean onset time of calling was not constant with either “lights on” or “light off”. There was however a constancy of the mean onset time of calling relative to the mid-point of both the photo- and scotophase at all photoperiods tested, indicating that females could measure the absolute duration of either the photo- or scotophase. Transferring females from one photoperiodic condition to another once calling had been initiated, determined that it was the “lights off” signal that P. unipuncta females used to phase set the clock governing circadian calling behaviour.Females subjected to a decrease of 4 or 6 h in the length of the scotophase following the initiation of calling required several days to adjust to the new photoperiodic regime and a high proportion of females did not call during the night following the transfer. A 4 or 6 h increase in the scotophase did not inhibit calling on the night following the transfer but females still required several days to adjust completely. However, females experiencing a 2 h increase or decrease in the duration of the scotophase were able to maintain normal calling behaviour. The results of these experiments are discussed in relation to the seasonal biology of the true armyworm and the hypothesis that this is a migrant species. 相似文献
9.
Basing on the pollen morphology of 22 Asian species, 17 from China, of PhylIanthus, 10 pollen types are recognized and described. Transformations of pollen type in this genus from a tricolporate one to a peripor(or) ste one are in succession and through 3 different pathways. It is interesting enough that the “successiformy” and “spiralizaton” pattern are all occurred. 相似文献
10.
Franklin F. Offner 《The Journal of membrane biology》1991,123(2):171-182
Summary A knowledge of the relationship between ion flow, both passive and active, ionic concentration, and membrane potential is essential to the understanding of cellular function. The problem has been analyzed on the basis of elementary physical and biophysical principles, providing a theoretical model of current flow and resting potential of cells, including those in epithelia. The model assumes that the permeability of the ion channets is not voltage dependent, but applies to gated channels when the gates are open. Two sources of nonlinearity of the current-voltage relationship are included in the analysis: ionic depletion and accumulation at the channels' mouths, and channel saturation at higher concentrations. The predictions of the model have been quantitative, validated by comparison with experiment, which has been limited to the only two cases in which adequate data was found. Application of the theory to the scala media of the mammalian cochlea has explained the source of its high positive potential and provided estimates of the Na+ and K+ permeabilities of the membranes of its marginel cess. This analysis provides a theoretically sound alternative to the widely used Goldman equation, the limited validity of which was emphasized by Goldman (D.E. Goldman, 1943,J. Gen. Physiol.27:37–60), as well as its derivatives, including the Goldman-Hodgkin-Katz equation for resting potentials. 相似文献
11.
Three new blood group systems, called “T,” “U,” and “V,” have been identified in the rhesus monkey (Macaca mulatta). Each system consists of a single antigenic factor (blood group) detected by a monospecific alloimmune reagent that agglutinates erythrocytes. The antisera that detect these blood groups were obtained following a series of alloimmunizations and absorption fractionizations of the resulting antisera to produce operationally monospecific typing reagents. Analyses of family data indicated that each blood group was controlled by an autosomal dominant gene and that each system was independent of previously defined systems. With the addition of these new blood groups, we can identify 16 different blood group systems and well over one hundred million possible phenotypes in this species. 相似文献
12.
Kinetic Theory Model for Ion Movement through Biological Membranes: III. Steady-State Electrical Properties with Solution Asymmetry
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An electrodiffusion model for plasma membrane ion transport, which takes into account the influence of high electric field strengths and ion-membrane molecule interactions, is presented and analyzed. A generalized Nernst-Planck equation for steady-state situations is derived which has electric field-dependent mobility and diffusion coefficients. Under the assumption of a constant electric field within the membrane, this equation is integrated to give a more general form of the Goldman equation. Based on this equation numerical computations of ionic chord conductance as a function of applied electric field strength were carried out for several permeant ion concentration ratios. The model is capable of yielding significantly larger rectification ratios than is the Goldman equation. Further, high field asymptotes to the current vs. electric field strength curve do not generally intersect at the origin. 相似文献
13.
Pollen grains of 990 species were examined and measured to test four predictions: (1) “Primitive” angiosperms will have starch-containing pollen; more advanced families will have starchless pollen. (2) Where Hymenoptera and Diptera use pollen nutritionally, there will be selection of starchless (oilcontaining) pollen, particularly where pollen is the only reward for visitors. (3) Conversely, in autogamous species, anemophilous species, and those pollinated by Lepidoptera or birds, the energetically more economical accumulation of starch will be seen. (4) Small pollen grains will be more likely to be starchless (oil-rich); starch-containing grains will tend to be larger. Prediction 1 is only partially supported by the results; contemporary representatives of primitive families often show starchless grains, and so do most “advanced” families. Strong intra-familial resemblances are found (and some between groups of families), but other families show mixtures of “starchy” and “starchless” species. The latter are more likely to show a fit between food reserve and pollination system. Prediction 2 is well supported. Prediction 3 is supported in that autogamous and anemophilous species show relatively high proportions of starchy grains, but the picture is complicated for them by apparent selection for starchlessness (oil-richness) in small pollen grains (prediction 4), and for the lepidopteran- and bird-pollinated species by selection for large starchless (or very large starchy grains) in species whose pollen tubes must traverse long styles. 相似文献
14.
The Bacillariophyta dominated over the other phyla and were mainly recorded in high densities during summer and autumn. The Chlorophyta and Myxophyta (Cyanobacteria) were represented by coccoid forms and by non-heterocystous, filamentous forms, respectively. Both were mainly recorded during summer and mostly absent during winter. Other phyla were occasionally recorded in low densities; the Chrysophyta being found in the River Elan and at one site on the River Wye during June 1980. Their members were considered as “contaminants” or “fall-out” from other communities. Pennate diatoms were the most “constant” species and either showed a general upstream or downstream increase or a general distribution throughout the study area. Populations of the same species colonising both sediments and stones were not correlated or insignificantly correlated with each other at most stations. It was concluded that sediments were unsuitable for algal colonisation. The River Elan and upper Wye were rated as oligosaprobic, the River Ithon and lower Wye as β-mesosaprobic and the River Lugg as α-mesosaprobic. 相似文献
15.
Colin Groves 《Evolutionary anthropology》2014,23(1):2-4
Biologists of the late eighteenth and early nineteenth centuries all bandied about the term “species,” but very rarely actually said what they meant by it. Often, however, one can get inside their thinking by piecing together some of their remarks. One of the most nearly explicit‐appropriately, for the man who wrote a book called The Origin of Species – was Charles Darwin 1 : “Practically, when a naturalist can unite two forms together by others having intermediate characters, he treats the one as a variety of the other… He later translated this into evolutionary terms: “Hereafter, we shall be compelled to acknowledge that the only distinction between species and well‐marked varieties is, that the latter are known, or believed, to be connected at the present day by intermediate gradations, whereas species were formerly thus connected”1:484‐5 相似文献
16.
Two forms of the equation for expression of the rate constant for electron transfer through a Marcus-type treatment are discussed. In the first (exergonic) form, the Arrhenius exponential term was replaced by its classical Marcus term; in the second (endergonic) form, the forward rate constant was replaced by the reverse rate constant (the forward rate constant in the exergonic direction), which was expanded to an equivalent Marcus term and multiplied by the equilibrium constant. When the classical Marcus treatment was used, these two forms of the rate equation give identical curves relating the logarithm of the rate constant to the driving force. The Marcus term for the relation between activation free-energy, ΔG#, reorganization energy, λ, and driving force, ΔGo, derived from parabolas for the reactant and product states, was identical when starting from exergonic or endergonic parabolas. Moser and colleagues introduced a quantum mechanical correction factor to the Marcus term in order to fit experimental data. When the same correction factor was applied in the treatment for the endergonic direction by Page and colleagues, a different curve was obtained from that found with the exergonic form. We show that the difference resulted from an algebraic error in development of the endergonic equation. 相似文献
17.
Jean‐François Ponge Dario Zuccon Marianne Elias Sandrine Pavoine Pierre‐Yves Henry Marc Théry Éric Guilbert 《Ecology and evolution》2017,7(23):9935-9953
Species traits have been hypothesized by one of us (Ponge, 2013) to evolve in a correlated manner as species colonize stable, undisturbed habitats, shifting from “ancestral” to “derived” strategies. We predicted that generalism, r‐selection, sexual monomorphism, and migration/gregariousness are the ancestral states (collectively called strategy A) and evolved correlatively toward specialism, K‐selection, sexual dimorphism, and residence/territoriality as habitat stabilized (collectively called B strategy). We analyzed the correlated evolution of four syndromes, summarizing the covariation between 53 traits, respectively, involved in ecological specialization, r‐K gradient, sexual selection, and dispersal/social behaviors in 81 species representative of Fringillidae, a bird family with available natural history information and that shows variability for all these traits. The ancestrality of strategy A was supported for three of the four syndromes, the ancestrality of generalism having a weaker support, except for the core group Carduelinae (69 species). It appeared that two different B‐strategies evolved from the ancestral state A, both associated with highly predictable environments: one in poorly seasonal environments, called B1, with species living permanently in lowland tropics, with “slow pace of life” and weak sexual dimorphism, and one in highly seasonal environments, called B2, with species breeding out‐of‐the‐tropics, migratory, with a “fast pace of life” and high sexual dimorphism. 相似文献
18.
No species is an island: testing the effects of biotic interactions on models of avian niche occupation
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Traditionally, the niche of a species is described as a hypothetical 3D space, constituted by well‐known biotic interactions (e.g. predation, competition, trophic relationships, resource–consumer interactions, etc.) and various abiotic environmental factors. Species distribution models (SDMs), also called “niche models” and often used to predict wildlife distribution at landscape scale, are typically constructed using abiotic factors with biotic interactions generally been ignored. Here, we compared the goodness of fit of SDMs for red‐backed shrike Lanius collurio in farmlands of Western Poland, using both the classical approach (modeled only on environmental variables) and the approach which included also other potentially associated bird species. The potential associations among species were derived from the relevant ecological literature and by a correlation matrix of occurrences. Our findings highlight the importance of including heterospecific interactions in improving our understanding of niche occupation for bird species. We suggest that suite of measures currently used to quantify realized species niches could be improved by also considering the occurrence of certain associated species. Then, an hypothetical “species 1” can use the occurrence of a successfully established individual of “species 2” as indicator or “trace” of the location of available suitable habitat to breed. We hypothesize this kind of biotic interaction as the “heterospecific trace effect” (HTE): an interaction based on the availability and use of “public information” provided by individuals from different species. Finally, we discuss about the incomes of biotic interactions for enhancing the predictive capacities on species distribution models. 相似文献
19.
Morphological Identities of Two Different Marine Stramenopile Environmental Sequence Clades: Bicosoeca kenaiensis (Hilliard, 1971) and Cantina marsupialis (Larsen and Patterson, 1990) gen. nov., comb. nov.
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Naoji Yubuki Tomáš Pánek Akinori Yabuki Ivan Čepička Kiyotaka Takishita Yuji Inagaki Brian S. Leander 《The Journal of eukaryotic microbiology》2015,62(4):532-542
Although environmental DNA surveys improve our understanding of biodiversity, interpretation of unidentified lineages is limited by the absence of associated morphological traits and living cultures. Unidentified lineages of marine stramenopiles are called “MAST clades”. Twenty‐five MAST clades have been recognized: MAST‐1 through MAST‐25; seven of these have been subsequently discarded because the sequences representing those clades were found to either (1) be chimeric or (2) affiliate within previously described taxonomic groups. Eighteen MAST clades remain without a cellular identity. Moreover, the discarded “MAST‐13” has been used in different studies to refer to two different environmental sequence clades. After establishing four cultures representing two different species of heterotrophic stramenopiles and then characterizing their morphology and molecular phylogenetic positions, we determined that the two different species represented the two different MAST‐13 clades: (1) a lorica‐bearing Bicosoeca kenaiensis and (2) a microaerophilic flagellate previously named “Cafeteria marsupialis”. Both species were previously described with only light microscopy; no cultures, ultrastructural data or DNA sequences were available from these species prior to this study. The molecular phylogenetic position of three different “C. marsupialis” isolates was not closely related to the type species of Cafeteria; therefore, we established a new genus for these isolates, Cantina gen. nov. 相似文献
20.
Lung health and normal mucus clearance depend on adequate hydration of airway surfaces. Because transepithelial osmotic gradients drive water flows, sufficient hydration of the airway surface liquid depends on a balance between ion secretion and absorption by respiratory epithelia. In vitro experiments using cultures of primary human nasal epithelia and human bronchial epithelia have established many of the biophysical processes involved in airway surface liquid homeostasis. Most experimental studies, however, have focused on the apical membrane, despite the fact that ion transport across respiratory epithelia involves both cellular and paracellular pathways. In fact, the ion permeabilities of the basolateral membrane and paracellular pathway remain largely unknown. Here we use a biophysical model for water and ion transport to quantify ion permeabilities of all pathways (apical, basolateral, paracellular) in human nasal epithelia cultures using experimental (Ussing Chamber and microelectrode) data reported in the literature. We derive analytical formulas for the steady-state short-circuit current and membrane potential, which are for polarized epithelia the equivalent of the Goldman-Hodgkin-Katz equation for single isolated cells. These relations allow parameter estimation to be performed efficiently. By providing a method to quantify all the ion permeabilities of respiratory epithelia, the model may aid us in understanding the physiology that regulates normal airway surface hydration. 相似文献