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  • Animals  (2,869)
  • Cell & Developmental Biology  (2,509)
  • 1995-1999  (5,378)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Machine vision and applications 8 (1995), S. 187-193 
    ISSN: 1432-1769
    Keywords: Tracking ; Segmentation ; Pigs ; Animals ; Computer vision
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract An algorithm was developed for the segmentation and tracking of piglets and tested on a 200-image sequence of 10 piglets moving on a straw background. The image-capture rate was 1 image/140 ms. The segmentation method was a combination of image differencing with respect to a median background and a Laplacian operator. The features tracked were blob edges in the segmented image. During tracking, the piglets were modelled as ellipses initialised on the blobs. Each piglet was tracked by searching for blob edges in an elliptical window about the piglet's position, which was predicted from its previous two positions.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 41 (1995), S. 238-246 
    ISSN: 1432-1432
    Keywords: Cellular slime molds ; Animals ; Fungi ; Plantae ; Maximum-likelihood method ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phylogenetic position of Dictyostelium inferred from 18S rRNA data contradicts that from protein data. Protein trees always show the close affinity of Dictyostelium with animals, fungi, and plants, whereas in 18S rRNA trees the branching of Dictyostelium is placed at a position before the massive radiation of protist groups including the divergence of the three kingdoms. To settle this controversial issue and to determine the correct position of Dictyostelium, we inferred the phylogenetic relationship among Dictyostelium and the three kingdoms Animalia, Fungi, and Plantae by a maximum-likelihood method using 19 different protein data sets. It was shown at the significance level of 1 SE that the branching of Dictyostelium antedates the divergence of Animalia and Fungi, and Plantae is an outgroup of the Animalia-Fungi-Dictyostelium clade.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 42 (1996), S. 183-193 
    ISSN: 1432-1432
    Keywords: Small-subunit ribosomal RNA ; Phylogeny ; Animals ; Fungi ; Plants ; Alveolates ; Heterokonts ; Stramenopiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The evolutionary relationships of four eukaryotic kingdoms—Animalia, Plantae, Fungi, and Protista—remain unclear. In particular, statistical support for the closeness of animals to fungi rather than to plants is lacking, and a preferred branching order of these and other eukaryotic lineages is still controversial even though molecular sequences from diverse eukaryotic taxa have been analyzed. We report a statistical analysis of 214 sequences of nuclear small-subunit ribosomal RNA (srRNA) gene undertaken to clarify these evolutionary relationships. We have considered the variability of substitution rates and the nonindependence of nucleotide substitution across sites in the srRNA gene in testing alternative hypotheses regarding the branching patterns of eukaryote phylogeny. We find that the rates of evolution among sites in the srRNA sequences vary substantially and are approximately gamma distributed with size and shape parameter equal to 0.76. Our results suggest that (1) the animals and true fungi are indeed closer to each other than to any other “crown” group in the eukaryote tree, (2) red algae are the closest relatives of animals, true fungi, and green plants, and (3) the heterokonts and alveolates probably evolved prior to the divergence of red algae and animal-fungus-green-plant lineages. Furthermore, our analyses indicate that the branching order of the eukaryotic lineages that diverged prior to the evolution of alveolates may be generally difficult to resolve with the srRNA sequence data.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of agricultural and environmental ethics 10 (1997), S. 249-267 
    ISSN: 1573-322X
    Keywords: Animals ; Asia ; consciousness ; Australia ; Hong Kong ; India ; Israel ; Japan ; New Zealand ; The Philippines ; Russia ; Singapore ; Thailand
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Philosophy
    Notes: Abstract The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals, and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan, New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand. Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness to be, and whether this relates to human ethics of the relationships.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 1-7 
    ISSN: 0886-1544
    Keywords: actin ; cytoskeleton ; contractile ring ; microinjection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cofilin is a small actin-binding protein which reguiates actin polymerization in a pH-dependent manner. Immunofluorescence microscopy with a monoclonal antibody for cofilin revealed that this protein is temporarily concentrated at the contractile ring during cytokinesis. Cofilin appeared to accumulate rapidly at the contractile ring during late stages of furrowing, and was finally enriched at the midbody. The concentration of cofilin at the contractile ring was observed in several kinds of cultured cells. Furthermore, cofilin introduced into living cells by a microinjection method was also concentrated at the contractile ring. These results suggest that cofilin is involved in actin reorganization during cytokinesis. © 1995 Wiley-Liss, Inc.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 38-49 
    ISSN: 0886-1544
    Keywords: Listeria monocytogenes ; actin ; profilin ; DNase I ; vitamin D-binding protein ; phalloidin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Infection of host cells by Listeria monocytogenes results in the recruitment of cytoplasmic actin into a tail-like appendage that projects from one end of the bacterium. Each filamentous actin tail progressively lengthenes, providing the force which drives the bacterium in a forward direction through the cytoplasm and later results in Listeria cell-to-cell spread. Host cell actin monomers are incorporated into the filamentous actin tail at a discrete site, the bacterial-actin tail interface. We have studied the consequences of microinjecting three different actin monomer-binding proteins on the actin tail assembly and Listeria intracellular movement. Introduction of high concentrations of profilin (estimated injected intracellular concentration 11-22 m̈M) into infected PtK2 cells causes a marked slowing of actin tail elongation and bacterial migration. Lower intracellular concentrations of two other injected higher affinity monomer-sequenstering proteins, Vitamin D-binding protein (DBP; 1-2 m̈M) and DNase I (6-7 m̈M) completely block bacterial-induced actin assembly and bacterial migration. The onset of inhibition by each protein is gradual (10-20 min) indicating that the mechanisms by which these proteins interfere with Listeria-induced actin assembly are likely to be complex. To exclude the possibility that Listeria recruits preformed actin filaments to generate the tails and that these monomer-binding proteins act by depolymerizing such performed actin filaments, living infected cells have been injected with fluorescently labeled phalloidin (3 m̈M). Although the stress fibers are labeled, no fluorescent phalloidin is found in the tails of the moving bacteria. These results demonstrate that Listeria-induced actin assembly in PtK2 cells is the result of assembly of actin monomers into new filaments and that Listeria's ability to recruit polymerization competent monomeric actin is very sensitive to the introduction of exogenous actin monomer-binding proteins. © 1995 Wiley-Liss, Inc.
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  • 7
    ISSN: 0886-1544
    Keywords: microfilamentous cytoskeleton ; actin binding proteins ; actin polymerization ; annealing ; non-muscle cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gelsolin, a Ca++ activated, 90 kd actin binding protein, can regulate actin polymerization in polymorphonuclear leukocytes (PMNs) via severing of filaments to dissolve gels or by capping of filament ends to limit polymerization. In Triton-lysed PMNs, 30% of gelsolin is bound to the Triton-soluble F-actin (TSF) pool and none is bound to the Triton-insoluble F-actin (TIF) pool. Calcium-activated PMNs exhibit concurrent temporal and quantitative TIF growth and TSF and total F-actin loss. To determine if gelsolin plays a role in regulating TSF pool size, we monitored gelsolin-actin interactions and TIF, TSF and G-actin content at 5 second intervals in PMNs activated with the calcium ionophore, ionomycin. Actin pools were measured by NBDphallacidin binding and by gel scans and expressed relative to basal; gelsolin-actin interactions were measured as change in the amount of EGTA-resistant gelsolin:actin (G:A) complexes and by immunoblot quantification of gelsolin in actin pools. In basal PMNs, 33% of PMN gelsolin is bound in 1:1 EGTA-resistant G:A complexes and TSF and TIF retain 30% and 0% of PMN gelsolin, respectively. By 20 seconds after ionomycin addition, TSF decreases, TIF increases and a fraction of gelsolin repartitions from the TSF to the TIF pool. At maximum change (60 seconds), total F-actin (TIF + TSF) and TSF decrease and TIF increases by 25%; gelsolin is bound to both TSF and TIF (35% of total gelsolin in each pool), and 1:1 EGTA-resistant G:A complexes increase from 33% to 70%. No changes occur in cells activated by ionomycin in the absence of Ca++. The data show Ca++ activated TIF growth and TSF loss are temporally and quantitatively associated with an increase in the percent of gelsolin bound to actin and the translocation of gelsolin from TSF to TIF. This is unique, since no other PMN activator is known to repartition gelsolin into TIF actin. Further, the Ca++ activated initial increase in TIF concurrent with a fall in TSF without a change in total F-actin or G-actin content suggest that TIF grows initially only by TSF annealing/cross-linking to TIF. Gelsolin may regulate these events. © 1995 Wiley-Liss, Inc.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 153-163 
    ISSN: 0886-1544
    Keywords: colchicine binding site ; MTC ; cod microtubules ; bovine microtubules ; MAPs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Isolated microtubules from cod (Gadus morhua) are apparently more stable to colchicine than bovine microtubules. In order to further characterize this difference, the effect of the colchicine analogue 2-methoxy-5-(2,3,4-trimethoxyphenyl)-2,4,6-cyclo heptatrien-1-one (MTC) was studied on assembly, as measured by turbidity and sedimentation analysis, and on polymer morphology. MTC has the advantage to bind fast and reversible to the colchicine binding site of tubulin even at low temperatures. It was found to bind to one site in cod brain tubulin, with affinity (6.5 ± 1.5) × 105M 1at both low or high temperature, similarly to bovine brain tubulin. However, the effect of the binding differed. At substoichiometric concentrations of MTC bovine brain microtubule assembly was almost completely inhibited, while less effect was seen on the mass of polymerized cod microtubule proteins. A preformed bovine tubulin-colchicine complex inhibited the assembly of both cod and bovine microtubules at substoichiometric concentrations, but the effect on the assembly of cod microtubules was less. At higher concentrations (5 × 10-5 to 1 × 10-3M), MTC induced a large amount of cold-stable spirals of cod proteins, whereas abnormal polymers without any defined structure were formed from bovine proteins. Spirals of cod microtubule proteins were only formed in the presence of microtubule associated proteins (MAPs), indicating that the morphological effect of MTC can be modulated by MAPs. The effects of colchicine and MTC differed. At 10-5M colchicine no spirals were formed, while at 10-4M and 10-3M, a mixture of spirals and aggregates was found. The morphology of the spirals differed both from vinblastine spirals and from the spirals previously found when cod microtubule proteins polymerize in the presence of high Ca2concentrations. The present data show that even if the colchicine binding site is conserved between many different species, the bindings have different effects which seem to depend on intrinsic properties of the different tubulins. © 1995 Wiley-Liss, Inc.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 34-44 
    ISSN: 0886-1544
    Keywords: microtubule ; MTOC ; mitosis ; MPM-2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In diverse cell types, monoclonal antibody MPM-2 recognizes a class of phosphorylated proteins related to microtubule organizing centers and abundant during mitosis. We have used this antibody in an attempt to identify the spatial and temporal localization of putative microtubule organizing centers in endosperm cells of the higher plant Haemanthus. Our results show that MPM-2 recognized epitope is present in interphase cells and enriched in mitotic cells. In interphase the antibody usually stains cytoplasmic granules. During the interphase-prophase transition immunoreactive material appears in the nucleus, at the nuclear envelope, and in association with microtubules. Concomitantly, we observed an increase of immunoreactivity of the cytoplasm. During mitosis the phosphorproteins recognized by MPM-2 are detected in the cytoplasm, in association with microtubules of the spindle, the phragmoplast, and in the newly-formed cell plate. After completion of mitosis, only the cell plate and cytoplasmic granules are MPM-2 positive. Extraction of the cells with Triton X-100 prior to fixation removes staining of the cytoplasm by MPM-2. The detergent resistant immunoreactive material remains associated with surrounding the nucleus microtubules of the prophase spindle, the core of kinetochore fibers, and the phragmoplast. In the phragmoplast, however, segments of microtubules which are distal to the cell plate are depleted of MPM-2.These data demonstrate that microtubule arrays of endosperm cells are phosphorylated during mitosis. Thus, similar to animal cells, interphase and mitotic microtubules of higher plants have different properties. Additionally, the localization of detergent resistant MPM-2 antigen points to the difference in microtubule nucleation/organization between higher plant and animal cells.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 59-65 
    ISSN: 0886-1544
    Keywords: flagella ; cane-shaped bend ; principal bend ; calcium ; membrane depolarization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To investigate the mechanism of the flagellar quiescence in sperm, we examined the effect of electric stimulation of individual spermatozoa of the sea urchin, Hemicentrotus pulcherrimus. Stimulation with a suction electrode attached to the sperm head elicited a flagellar quiescence response, in which the sperm showed a typical cane-shaped bend in the proximal region of the flagellum when the electrode was used as anode. Cathodic stimulation also induced quiescence, but was much less effective than anodic stimulation. During the quiescence response, which lasted for 1-3 s, no new bend was initiated, and subsequently the flagellum resumed normal beating. The quiescence response required the presence of Ca2+ (〉2 mM) in sea water, and was inhibited by Co2+ and La3+. At low Ca2+ concentrations (2-5 mM), the angle of the cane-shaped bend was smaller than that at 10 mM Ca2+; thus the angle of the cane-shaped bend, characteristic of the quiescence response is dependent on Ca2+ concentration. These results suggest membrane, followed by an influx of Ca2+ into the flagellum through Ca2+ channels. The increase in Ca2+ concentration within the flagellum affects the amount of sliding and thus produces a cane-shaped proximal bend of various angles, white inhibiting both the propagation of the proximal bend (principal bend) and the formation of a new reverse bend.
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