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  • Analytical Chemistry and Spectroscopy  (1,518)
  • Cell & Developmental Biology  (1,408)
  • General Chemistry  (1,210)
  • Chemical Engineering  (638)
  • GEOPHYSICS  (606)
  • 1990-1994  (5,380)
  • 1970-1974
  • 1910-1914
  • 1993  (5,380)
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  • 1990-1994  (5,380)
  • 1970-1974
  • 1910-1914
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  • 101
    Electronic Resource
    Electronic Resource
    Distribution and morphology of motoneurons innervating different muscle fiber types in an amphibian muscle complex (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 327-338 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution and morphology of motoneurons innervating specific types of muscle fibers in the levator scapulae superior (LSS) muscle complex of the bullfrog (Rana catesbeiana) and tiger salamander (Ambystoma tigrinum) were studied by retrograde labelling with cholera toxin-conjugated horseradish peroxidase (CT-HRP). The LSS muscle complex in both of these amphibians has a segregated pattern of muscle-fiber types (tonic; fast oxidative-glycolytic twitch [FOG]; fast glycolytic twitch [FG]) along an anteroposterior axis. The entire motor pool was labelled by injection of CT-HRP into the whole LSS muscle complex. The motoneurons innervating specific fiber types were labelled by injection of CT-HRP into certain muscle regions. The organization of the motoneuron pool of the LSS complex of both species was arranged in two columns - one ventrolateral and one medial. In bullfrogs, the ventrolateral column contains motoneurons innervating FG and tonic fiber types and the medial column contains motoneurons innervating FOG fiber types. In tiger salamanders, the ventrolateral column contains motoneurons innervating FG fiber types and the medial column contains motoneurons innervating FOG and tonic fiber types. The different motoneuron types also have different soma sizes and patterns of dendritic arborization. In both species, FG motoneurons are the largest, whereas FOG motoneurons are intermediate in size and tonic motoneurons are the smallest. In bullfrogs, the main dendrites of FG motoneurons extend into the dorsolateral and the ventrolateral gray matter of the spinal cord, whereas the dendrites of FOG motoneurons extend into the ventral and medial cord. In the tiger salamander, dendrites of FG motoneurons extend into the ventrolateral spinal cord and dendrites of the FOG motoneurons extend more generally into the ventral cord. Dendrites of tonic motoneurons in both amphibians were small and short, and difficult to observe. These results establish that motoneurons innervating different types of muscle fibers in the LSS muscle complex are segregated spatially and display consistent morphological differences. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052160308
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  • 102
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    Ultrastructure of the cardiac and pyloric glands of the gastric mucosa of the South African hedgehog, Atelerix frontalis (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 216 (1993), S. 351-359 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cardiac and pyloric glands in the gastric mucosa of the South African hedgehog, Atelerix frontalis, are described. The cardiac area of the stomach contains proper cardiac glands and lacks undifferentiated fundic glands. The cardiac glands are simple tubular, coiled, and lined with columnar cells ultrastructurally similar to those of the gastric surface epithelium. Secretory granules with varying electron densities fill the apical cytoplasm of these cells. In contrast to other mammals, these glands lack mucous neck cells. The neck of the pyloric glands contains only a single cell type, whereas the basal regions of these glands contain “light” and “dark” cells. The secretory granules in the “dark” cells and the pyloric neck cells have a moderate electron density and often contain an electron dense core. An electron-lucent cytoplasm with numerous polysomes is characteristic of the “light” cells. Some “light” cells contain electron-dense granules in the apical cytoplasm. The presence of only neutral mucins in the cardiac gland cells denotes the absence of mucous neck cells. The acidic mucins within the pyloric neck cells seem to indicate that these cells are mucous neck cells, whereas the neutral mucins within the basally located pyloric gland cells show at least a partial functional difference from the pyloric neck cells. © 1993 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052160310
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  • 103
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    Jaws and teeth of american cichlids (Pisces: Labroidei) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 1-36 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The morphology of the upper, lower, and pharyngeal jaws is very similar among American cichlids. Common conditions are: (1) the presence of a premaxillary dentigerous arm shorter than the ascending arm (exceptions are Astronotus, Cichla, and Crenicichla semifasciata), (2) a narrow coulter area; in contrast, a broad coulter area is found in the Crenicichline Group, in certain chaetobranchines, and in Apistogramma, (3) the mandibular sensory canal exists to the skin through five or six simple pores; in contrast, it exits through numerous small pores that increase in number during ontogeny in the Chaetobranchine Group, certain crenicichlines, such as Cichla, Crenicichla lepidota, Crenicichla proteus, and Crenicichla vittata, and certain genera of the Cichlasomine Group A, such as Caquetaia, Petenia, Neetroplus, and “Cichlasoma,” and (4) the premaxilla and dentary of American cichlids commonly bear unicuspid, conical teeth with a few exceptions such as Neetroplus (with scraping blade teeth) and “Cichlasoma” facetum, “C.” cyanoguttatum, “C.” guttulatum, and “C.” spilurum (with bicuspid [hooked] teeth). In contrast to the near uniformity of the upper and lower jaws, the upper and lower pharyngeal jaws present a great diversity of tooth shapes. At least seven types are found in American cichlids; usually, several types exist on a single tooth plate, but the combination of tooth types differs among some genera.The pharyngobranchial 4 tooth plate has significant evolutionary transformations in labroids. The caudal margin of the pharyngobranchial 4 tooth plate bears the frayed zone in cichlids and embiotocids. The presence of a broad frayed zone bearing one to seven concavities represents a synapomorphy for the family Cichlidae, whereas a deep, narrow frayed zone is a synapomorphy of Embiotocidae. The absence of the frayed zone is a synapomorphy of Pomacentridae, whereas the loss of the pharyngobranchial 4 is a synapomorphy of Labridae. © 1993 Wiley-Liss, Inc.
    Additional Material: 20 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170102
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  • 104
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    Fine structure of the nephridial muscle layer cells of Phascolosoma granulatum (Sipuncula) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 45-54 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The nephridial muscle layer of Phascolosoma granulatum consists of a network of longitudinal and circular cells separated by connective tissue matrix. The muscle fibers are densely packed with thick and thin myofilaments, among which are scattered cytoplasmic dense bodies. The nucleus and noncontractile cytoplasmic organelles occupy a lateral projection from the contractile portion of the fiber. Cytoplasmic dense bodies are the result of a clustering of an indeterminate number of the thin actin filaments that fill the cytoplasm between thick filaments. Attached to the cytoplasmic face of the cell membrane are membrane-associated electron-dense plaques. These sites are linked to the contractile myofilaments by narrow filamentous bridges. Extracellular narrow filaments extend from these plaques to collagen fibers of the connective tissue matrix. Differences in length of the dense plaques may be related to differences in thick myofilament diameter in three types of muscle fiber, types A, B and C, statistically distinguished by mean fiber size differences. The plaques may serve as connecting links for the transmission of tension from contractile units to the connective tissue of the muscle layer. © 1993 Wiley-Liss, Inc.
    Additional Material: 19 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170104
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  • 105
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    Muco-follicle cells of the jelly coat in the oocyte envelope of the sheatfish (Silurus glanis L.) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 37-43 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During early vitellogenesis of the oocytes of Silurus glanis, the follicular cells proliferate, their epithelial organization becomes disrupted, and they transform into an irregularly structured large mass of cells engaged in intensive secretory activity. They contain nuclei, rough endoplasmic reticulum, Golgi bodies, and secretory inclusions termed “acorn bodies,” which are synthesized in the cytoplasm. The acorn bodies have two components: an electron-dense cap and a moderately electron-dense body. As development proceeds, the acorn bodies become modified into spherules of mucous material, the mucosomes. The electron-dense part persists as a small calotte or crescent often irregularly structured at the periphery of the mucosome, and fragments of it are dispersed into the interior of the mucosomal body. The mucosomes are membrane-bound and contain small granules, 55 nm in diameter.At the end of vitellogenesis, the follicle cells are filled with mucosomes, and cytoplasmic residua can only sparingly be observed among them. Oocytic microvilli extend through the zona radiata and intermingle with follicular cell processes in the cleft between the zona radiata and the belt of mucosomes during growth of the oocyte. Capillaries develop in connective tissue of the theca layer as vitellogenesis proceeds. © 1993 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170103
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  • 106
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    Scaling of cursoriality in mammals (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 55-63 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Data on limb bone lengths from 64 mammalian species were combined with data on 114 bovid species (Scott, '79) to assess the scaling of limb lengths and proportions in mammals ranging from 0.002 to 364 kg. We analyzed log-transformed data using both reduced major axis and least-squares regression to focus on the distribution across mammals of two key traits - limb length and metatarsal/femur ratio - associated with cursorial adaptation. The total lengths of both fore and hindlimbs scale in a manner very close to the M0.33 predicted by geometric similarity. Thus the relative limb lengths of large mammals, including bovids, generally regarded among the most cursorial of mammals, are very similar to those of the rodents and insectivores in this sample. Metatarsal/femur ratio also shows little change with changing mass, although bovids tend to have relatively longer metapodials than do other families in the sample. We argue that many of the remaining morphological traits associated with cursoriality (e.g., reduction in joint mobility and number of distal limb bone elements) promote cursoriality only at large body sizes. These results lead us to question the general perception that cursoriality is most widespread among large mammals. We also suggest that discussions of cursoriality should focus explicitly on the two partially independent aspects of performance that are otherwise confounded under this general term - speed and the ability to cover substantial distance. © 1993 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170105
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  • 107
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    Histomorphometry of immature rat testis after heating (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 65-74 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The scrotal testes of albino rats aged 35 and 45 days were immersed in water at constant temperatures of 43°C, 44°C, or 45°C for periods of 15-45 min in a special heating device. At an age of 60 days, the rats were mated in individual cages with two primiparous rats each. At an age of 90 days, they were killed and their testes were histologically processed. Rats with testes that had been subjected to heating when the animals were 45 days old showed both alterations of the seminiferous tubules and a decrease in fertilizing capacity. The effect of heat was greater in animals at 45 than at 35 days of age. In heat-treated testes, tubules contained PAS-positive concretion, sometimes engulfed by macrophage-derived giant cells and multinucleate cells derived from spermatids that failed to separate during spermiogenesis. The decrease in testicular volume observed after heat treatment was due mainly to reduced parenchymal volume. Thermic lability of seminiferous stem cells increases with age until adulthood, and recovery from heat injury declines. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170106
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  • 108
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    Electromyographic and kinematic studies of tail movements in dogs during treadmill locomotion (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 105-113 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electromyographic (EMG) activities of three tail muscles, the extensor caudae lateralis (ECL), abductor caudae externus (ACE), and flexor caudae longus (FCL), were recorded bilaterally in seven adult dogs during walking, trotting, and galloping on a treadmill. Each dog's movements were recorded with a 16 mm high-speed camera system, and angular movements of the tail were analyzed. During walking and trotting, reciprocal EMG bursts were observed between right and left tail muscles and corresponded with lateral movements of the tail.The tonic discharges that were observed in ECL and FCL seemed to maintain the position of the tail. During galloping, synchronized EMG activity of all tail muscles produced reactive torques to counter those generated by cyclic limb movements and kept the tail in a stable position. These results suggest that tail movements are important in maintaining body balance during locomotion in the dog. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170109
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  • 109
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    Ultrastructural study of the mental body of Hydromantes genei (Amphibia: Plethodontidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 75-86 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mental glands of Hydromantes genei are considered a specialized form of the urodele serous cutaneous glands. Use of a variety of techniques of maceration and digestion as well as transmission electron microscopy (TEM) and scanning electron microscopy (SEM) has shown the three-dimensional morphology of secretory and myoepithelial cells. Secretory cells are pyramidal and rest on an almost continuous layer of myoepithelial cells. The latter have a long ribbon-like body from which branch off transversal and longitudinal processes with swallow-tailed ends. Cytoplasmic processes of secretory cells, containing irregular dense vesicles, squeeze through clefts between myoepithelial cells and may reach, at some points, the basal lamina. The interstices between myoepithelium and secretory cells are extraordinarily rich in nerve endings with clear vesicles. The glandular outlets appear as elliptical stomata in the superficial layer of the epidermis and are lined by horny cells, which invaginate to circumscribe the excretory duct. The morphological results indicate that the myoepithelium of Plethodontidae mental glands differ in some respects from that of amphibian serous cutaneous glands. A double polarity for the secretory cells is also suggested. © 1993 Wiley-Liss, Inc.
    Additional Material: 17 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170107
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    Differentiation of cytoplasmic organelles and storage of yolk during vitellogenesis in Hemidiaptomus ingens and Mixodiaptomus kupelwieseri (Copepoda, Calanoida) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 87-103 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: These investigations concern two freshwater calanoid copepods Hemidiaptomus ingens and Mixodiaptomus kupelwieseri. The first aspect of the research relates to the processes involved in the formation and the differentiation of the ooplasmic organelles at the time of primary vitellogenesis. During this phase, a number of complex associations develop in the ooplasm. They consist chiefly of nuage-like structures, corresponding to extruded nuclear material, and vesicular formations, some arising from the nuclear envelope and the others neoformed in the ooplasm. These associations represent centers of maturation for ribosomes and synthesis for reticulum membranes. Annulate lamellae may be observed near these associations. Biogenesis of the reticulum always precedes the differentiation of the Golgi apparatus. Indeed, the dictyo-somes develop in characteristic complexes including endoplasmic reticulum cisternae and numerous vesicles resulting from intensive blebbing from cisternae. The second aspect of this research concerns yolk synthesis and accumulation of hyaloplasmic inclusions. A preliminary synthesis of yolk occurs early in these complexes and becomes more important after achievement of Golgi apparatus biogenesis. However, the most important yolk storage results from exogenous molecules and consists of complex globules, which develop into the ooplasm during secondary vitellogenesis. Formation of these globules is associated with the accumulation of two categories of inclusions in the hyaloplasm, i.e., lipid droplets and clusters of glycogen particles. At the end of vitellogenesis, a new type of endogenous material develops into small cisternae localized in the cortical ooplasm. © 1993 Wiley-Liss, Inc.
    Additional Material: 31 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170108
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052170201
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  • 112
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    Spermathecal cytology of Ambystoma opacum (Amphibia: Ambystomatidae) and the phylogeny of sperm storage organs in female salamanders (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 115-127 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sperm storage glands, spermathecae, were examined from mated female Ambystoma opacum during the breeding season. No differences occur in the spermathecal ultrastructure of individuals sacrificed prior to oviposition and those sacrificed within 3 days of removal from tended clutches of recently oviposited eggs. The simple tubuloalveolar glands produce two types of secretory vacuoles. Apical secretory vacuoles contain glycosaminoglycans for export into the lumen to bathe stored sperm, perhaps providing the chemical/osmotic environment necessary for sperm quiescence. The other type of secretory vacuole contains an unsaturated lipid that is produced for export into the connective tissue surrounding the spermathecae. The role of this secretion may involve the contraction of myoepithelial cells, resulting in sperm expulsion. Some sperm undergo degradation in the spermathecal epithelium, and an interepithelial leukocyte was observed in one specimen. Apical secretory vacuoles and sperm are absent from the spermathecae of a specimen sacrificed 62 days after removal from a tended egg clutch. This is the first report on the spermathecal cytology of a salamander from the Ambystomatidae, and comparisons with salamanders from other families provide a morphological basis for considering spermathecae polyphyletic within the Caudata. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1052170110
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  • 113
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    Central projections of cheliceral mechanoreceptors in the spider Cupiennius salei (Arachnida, Araneae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 129-136 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Central projections of lyriform organs and tactile hairs on the chelicerae of the wandering spider Cupiennius salei were traced using anterograde cobalt fills. Different fibers arising from both mechanoreceptor types arborize in the cheliceral ganglia, which are part of the tritocerebrum, and in sensory longitudinal tracts in the center of the suboesophageal nerve mass together with afferent fibers arising from mechanoreceptors on the walking legs and the pedipalps. This convergence of sensory projections in the sensory longitudinal tracts might provide the anatomical basis for the coordination of the movements of different extremities during prey capture and feeding. The findings also support the hypothesis that the tritocerebrum originally was a preoral ganglion in spiders. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052170202
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  • 114
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    Trigeminal primary afferent projections to the spinal cord of the frog, Rana ridibunda (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 137-146 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution in the spinal cord of the trigeminal primary projections in the frog Rana ridibunda was studied by means of the anterograde transport of horseradish peroxidase (HRP). Upon entering the medulla via the single trigeminal root, a conspicuous descending tract that reaches the cervical spinal cord segments is established. This projection arises in the ophthalmic (V1), maxillary (V2), and mandibular (V3) trigeminal nerve subdivisions. In the spinal cord, only a minor somatotopic arrangement of the trigeminal fibers was observed, with the fibers arising in V3 terminating somewhat more medially than those from V1 and V2. A dense projection to the medial aspect of the spinal cord, above the central canal, primarily involves V3. Each trigeminal branch sends projections at cervical levels to the contralateral dorsal field, and those from V2 are most abundant. Bilateral experiments with HRP application show convergence of primary trigeminal and spinal afferents within the dorsal field of the spinal cord.The pattern of arrangement of the trigeminal primary afferent fibers in the spinal cord of this frog largely resembles that of amniotes. However, the organization seems simpler and the slight somatotopic distribution of V1, V2, and V3 fibers is similar to the condition in other anamniotes. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052170203
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  • 115
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    Internal micromorphology of the frons plate in females of the oriental hornet (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 217 (1993), S. 147-159 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scanning electron microscopy and energy dispersive x-ray analysis (SEM/EDS) have been used to study the internal micromorphology of the frons plate in the Oriental hornet, Vespa orientalis. A conical shaped organ was described which is recessed into the frons plate and projects toward the interior of the acoustic box. The latter is located on the inner side of the frons plate. On the exterior of the conical region are observed aggregates containing Ca and Si, and a thin transparent membrane bearing a hole in its center. The innermost surface of the conical structure terminates bluntly as a convex lentiform tip, bearing a transparent oval-shaped window in its center. The conical organ, excepting the window, is enclosed in several layers of epithelium.The structure of this many-layered conical organ is highly complex; its numerous sub-structures and the possible role as a gravity sense organ are discussed. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052170204
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    Ultrastructure of the light organ and immunocytochemical localization of luciferase in luminescent marine ostracods (Crustacea: Ostracoda: Cypridinidae) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 181-193 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the upper lip, which is the location of the light organ in luminescent ostracods, is described for two species of marine ostracods (Vargula graminicola, and V. tsujii). The light organ contains four primary cell types (here designated A-D) readily identified both by the types of vesicles that they contain and their location. Cell type A, restricted to the center of the light organ, has vesicles that are homogeneous throughout. Cell type B has vesicles with a single electron-dense central area. This cell is most common in the lateral regions but is also found in the tusks. Immunocytochemical experiments revealed that luciferase is found in B cells, but not in any other cells or in control specimens. Cell type C has vesicles containing many electrondense microstructures; this cell type is the least common and is found along with B cells within the lateral margins of the light organ. Cell type D has granulated vesicles and is restricted to the tusks. Metachromatic staining with toluidine blue suggests that the vesicles contain acidic mucosubstances. The cells of the light organ are very long (360-460 μm) and extend through its entire length. The cells found exclusively in the tusks are shorter (ea. 150 μm). All cells possess similar polarity: proximal synthesis, middle transitional, and distal secretory regions. These cells terminate ventrally at nozzles on the anterior portion of the upper lip, and on the tusks. The upper lip and light organ possess two large longitudinal muscles, a central muscle, and several smaller “bridle” muscles that attach onto sclerotized ridges. Various hypotheses for the storage and secretion of light organ materials are suggested relative to these morphological data. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/jmor.1052180207
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    Stages of oocyte development in the zebrafish, Brachydanio rerio (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 203-224 
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    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oocyte development has been divided into five stages in the zebrafish Brachydanio rerio, based on morphological criteria and on physiological and biochemical events. In stage I (primary growth stage), oocytes reside in nests with other oocytes (Stage IA) and then within a definitive follicle (Stage IB), where they greatly increase in size. In stage II (cortical alveolus stage), oocytes are distinguished by the appearance of variably sized cortical alveoli and the vitelline envelope becomes prominent. In stage III (vitellogenesis), yolk proteins appear in oocytes and yolk bodies with crystalline yolk accrue during this major growth stage. Ooctes develop the capacity to respond in vitro to the steroid 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) by undergoing oocyte maturation. In stage IV (oocyte maturation), oocytes increase slightly in size, become translucent, and their yolk becomes non-crystalline as they undergo final meiotic maturation in vivo (and in response to DHP in vitro). In stage V (mature egg), eggs (approx. 0.75 mm) are ovulated into the ovarian lumen and are capable of fertilization. This staging series lays the foundation for future studies on the cellular processes occurring during oocyte development in zebrafish and should be useful for experimentation that requires an understanding of stage-specific events. © 1993 Wiley-Liss, Inc.
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    Quantitative investigations of spinal motoneurons and their synaptic structures in a teleost: A morphometrical analysis with special reference to axosomatic synapses (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 281-300 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructural and morphometrical synaptology of the spinal motoneurons in Carassius auratus (goldfish) was analyzed based on profiles of 23 photomontages of large motoneurons and 25 putative small motoneurons with a semiautomatic digitizing system connected with a computer. In the 23 large motoneurons (mean circumference, 142.45 ± 39.76 μm) the total linear perikaryal circumference was 3,276.28 μm, of which 1,548.9 μm (46.1 ± 13.9%) was covered by terminal boutons. In contrast, a total linear perikaryal circumference of 1,375.24 μm (55.01 ± 14.34 μm) of the 25 putative small motoneurons was covered with terminal boutons only occupying a length of 287.45 μm (19.8 ± 11.9%). There were a total of 1,045 boutons on the large motoneurons and 204 on the small ones. The distribution of S- and F-type boutons may reflect excitatory and inhibitory synapses. The relative number of S-type boutons (58%) was larger than that of F-type boutons (42%) in the large neurons and showed similar values (S-type, 57%; F type, 43%) in the small ones. This is in contrast to mammalian spinal motoneurons in which F-type boutons are more prevalent than the S-type. The total numbers of the axosomatic boutons in large and small neurons were estimated, based on geometrical assumptions and found to differ substantially (840 vs. 59). This indicates large quantitative differences in the total number of synaptic inputs with the large motoneurons having a greater more axo-somatic bouton density. No large M- and C-type boutons occur on the spinal motoneurons of goldfish, suggesting a synaptic organization which is simple compared to that of terrestrial vertebrates. © 1993 Wiley-Liss, Inc.
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    Distribution of calcium-ATPase in developing teeth of embryonic American alligators (Alligator mississippiensis) (1993)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 218 (1993), S. 249-256 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Light microscopic and ultrastructural observations were carried out to evaluate the cell morphology and histochemistry (calcium-ATPase activity) of developing teeth in embryonic American alligators (Alligator mississippiensis). Ca-ATPase activity was observed in the distal and lateral cell membranes, rough endoplasmic reticulum (rER), mitochondria, vacuoles, and other organelles of the ameloblast, but only in the distal cell membrane and process of the odontoblast. Enzyme activity in the ameloblasts increased gradually during development. These sites of enzyme activity are related to mineralization of the enamel layer, similar to that in mammalian tooth development. Alligator teeth are heavily mineralized like mammalian teeth; however, alligator ameloblasts have undeveloped distal processes during mineralization in contrast to mammalian ameloblasts in which Tomes' processes are found near the distal portion of ameloblasts at maturation stage. The localization of intense enzyme activity in the distal and lateral ameloblast cell membrane suggests that these regions are the site of accumulation of calcium as enamel differentiates in the developing tooth. © 1993 Wiley-Liss, Inc.
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    Action of tolytoxin on cell morphology, cytoskeletal organization, and actin polymerization (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 39-48 
    Details
    ISSN: 0886-1544
    Keywords: actin ; microfilament ; stress fiber ; cytochalasin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tolytoxin, a cytostatic, antifungal macrolide produced by blue-green algae of the genus Scytonema, is a potent, reversible inhibitor of cytokinesis in cultured mammalian cells. Treatment of KB cells with 2-16 nM tolytoxin results in profound morphological changes, beginning with the formation of zeiotic processes and culminating in nuclear protrusion. In L1210 cells, cytokinesis is inhibited by as little as 2 nM tolytoxin, while karyokinesis proceeds normally, resulting in polynucleation. Tolytoxin specifically disrupts microfilament organization in A10 cells, while having no apparent effect on microtubules or intermediate filaments. Tolytoxin inhibited actin polymerization in vitro and also caused the depolymerization or fragmentation of F-actin in vitro. Tolytoxin exhibits effects that closely resemble those of cytochalasin B but is effective at concentrations 1/50-1/1,000 that of cytochalasin B. © 1993 Wiley-Liss, Inc.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240201
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    Native microtubules with a variable number of protofilaments (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 49-53 
    Details
    ISSN: 0886-1544
    Keywords: insect sperm tail ; trichopteran axoneme ; computer image analysis ; axonemal ultrastructure ; accessory tubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Insect spermatozoa are characterized by having a set of accessory tubules that surrounds the microtubular doublets of the axoneme and that are formed from the B-subtubules of the doublets. In trichopteran species, the accessory tubules have an unusually large diameter. Those of one species, Odontocerum albicorne, were seen to have a number of protofilaments that is 19 in the main part of the axoneme, but gradually decreasing to 18, 17, and 16 near the distal tip. The accessory tubule of the trichopteran axoneme has an asymmetrical shape and a skewed orientation, which makes it easy to distinguish a tubule that is viewed from its plus-end from one viewed from the minus-end. The shape of a cross-sectioned protofilament in the trichopteran accessory tubules differs from that of microtubules in general, including accessory tubules of other insects, by being polygonal with the most acute angle pointing centripetally. © 1993 Wiley-Liss, Inc.
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    Molecular cloning and expression of the chicken smooth muscle γ-actin mRNA (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 67-81 
    Details
    ISSN: 0886-1544
    Keywords: development ; cDNA ; actin isoform ; enteric ; myogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have investigated the expression of chicken smooth muscle γ-actin mRNA by isolation and characterization of cDNAs representing this actin isoform and utilizing the cDNA to probe RNA from adult and developing cells. Nucleotide sequence elucidated from an apparent full length smooth muscle γ-actin cDNA revealed that it contained 94 bp of 5′ non-translated sequence, an open reading frame of 1131 bp, and 97 bp of 3′ non-translated sequence. Within the 376 amino acid sequence deduced from the chicken cDNA were diagnostic amino acids at the NH2- and COOH-terminal regions which provided unequivocal identification of the γ-enteric smooth muscle actin isoform. In addition, the chicken γ-enteric actin deduced from our cDNA clones was found to differ from the sequence reported in earlier protein studies [J. Vandekerckhove and K. Weber, FEBS Lett. 102:219, 1979] by containing a proline rather than a glutamine at position 359 of the protein, indicating that the avian γ-enteric actin isoform is identical to its mammalian counterpart. Comparison of the 5′ and 3′ non-translated sequence determined from the chicken cDNA to that elucidated for rat, mouse, and human showed that there is not a high degree of cross-species sequence conservation outside of the coding regions among these mRNAs. Northern hybridization analyses demonstrated that the γ-enteric actin mRNA is expressed in adult aorta and oviduct tissues but not in adult skeletal muscle, cardiac muscle, liver, brain, and spleen tissues. The γ-enteric actin mRNA was first observed in measurable quantities in gizzard tissue from 4-5 day embryos and increased in content in developing smooth muscle cells through 16-17 embryonic days. Following this initial increase during embryonic development, the γ-enteric actin mRNA exhibits a decline in content until ∼7 days posthatching, after which there is an increase in content to maximal levels found in adult gizzard tissue. In general, the developmental appearance of the γ-enteric mRNA parallels that observed for this protein in previous studies indicating that the developmental expression of smooth muscle γ-actin is regulated, in part, by an increased content of mRNA in chicken visceral smooth muscle cells during myogenesis. © 1993 Wiley-Liss, Inc.
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    URL: http://dx.doi.org/10.1002/cm.970240108
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    Protein kinases are required for embryonic neural crest cell galvanotaxis (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 54-66 
    Details
    ISSN: 0886-1544
    Keywords: protein kinase ; galvanotaxis ; motility ; phorbol ester ; neural crest ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Embryonic quail neural crest cells migrate towards the negative pole of an imposed dc electric field as small as 7 mV/mm (0.4 mV per average cell length). The involvement of protein kinases in the mechanism utilized by these cells to detect and respond to such imposed fields was tested through the use of several kinase inhibitors. Evidence for the involvement of protein kinase C (PKC) included: (1) inhibition of the directed motility by 1 μM sphingosine that was reversed by the addition of the phorbol ester, PMA; (2) stimulation of a faster response to the imposed field by PMA; and (3) inhibition of the directed translocation by 5 μM H-7. However, another PKC inhibitor, staurosporin, did not inhibit the directed translocation (1 nM-1 μM). We also found evidence for the involvement of either cAMP- or cGMP-dependent protein kinase. The galvanotactic response was partially inhibited by the addition of 10 μM H-9 and the response was enhanced in the presence of the phosphodiesterase inhibitor, IBMX. However, the adenylate cyclase stimulant, forskolin, had no significant influence on the directed motility, although it reduced the average cell velocity. While these experiments suggest that cAMP- or cGMP-dependent protein kinase or PKC may be involved in the galvanotaxis response, two other protein kinases appeared not to be required. The myosin light chain kinase inhibitor, ML-7, had no effect on the directed motility in an imposed field, so myosin light chain kinase may not be required for galvanotaxis. Similarly, 5 μM W-7 had no significant effect on the directed translocation, suggesting that calmodulin-dependent protein kinase is not involved.Interestingly, the continuous activity of a protein kinase is apparently not required for the directed translocation response. The addition of the PKC and cAMP-dependent protein kinase inhibitor, H-7, after the cells had been exposed to the field for 1 hour, had no effect on the subsequent directed translocation. Thus, for these inhibitors to block the directed translocation, they must be present at the same time as the initial field application. This implies that an integral step in the cellular response mechanism for galvanotaxis involves the stimulation of a protein kinase whose effect is long lasting. © 1993 Wiley-Liss, Inc.
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    Actin-binding protein is a component of bovine erythrocytes (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 100-108 
    Details
    ISSN: 0886-1544
    Keywords: actin-binding protein ; filamin ; erythrocytes ; membrane skeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Actin-binding protein (ABP) is a well-characterized polypeptide capable of crosslinking filamentous actin. To date, this polypeptide has been shown to exist in a number of tissues and cultured cell lines. This report shows that by using a panel of three monoclonal antibodies for immunoblotting and immunofluorescence analysis, that ABP is present in bovine erythrocytes. Moreover, the data obtained suggest that this protein is a component of the erythrocyte membrane skeleton. Additionally, bovine erythrocyte ABP is shown to possess both an apparent molecular weight and an isoelectric point identical to that of bovine smooth muscle filamin, implying that these two polypeptides are identical. © 1993 Wiley-Liss, Inc.
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    Cytoskeletal sheets of mammalian eggs and embryos: A lattice-like network of intermediate filaments (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 85-99 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeletal sheets ; intermediate filaments ; blastomere - blastomere contact ; cross-bridges ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mammalian eggs and embryos possess a major cytoskeletal network composed of large planar “sheets” distributed throughout the cytoplasm. Cytoskeletal sheets are found neither in mammalian somatic cells nor in eggs or embryos of non-mammals. In this study, we have investigated the structural composition of the sheets in eggs and embryos of the golden Syrian hamster by (1) analysis of replicas from quick-frozen, deep-etched specimens, (2) analysis of thick, resinembedded specimens using an intermediate voltage electron microscope (IVEM), (3) laser diffraction of EM images, (4) differential extraction with detergents, and (5) immunocytochemistry. Our results indicate that each sheet is composed of two closely apposed arrays of 10-nm filaments. Each filament within an array is held in register with its neighbor by lateral cross-bridges and the two parallel arrays of filaments are interconnected by periodic cross-bridges about 20 nm in length. Laser diffraction of negatives from IVEM images indicates that each array is composed of fibers that form a square lattice, and the two arrays are positioned in register by cross-bridges forming a single sheet. This lattice forms the skeleton of the sheets which is covered with a tightly packed layer of particulate material. By incubation in media containing different ratios of mixed-micelle detergents, it is possible to remove components sequentially from the sheets and to extract the particulate material. Immunocytochemical localization demonstrates that the sheets bind antibodies to keratin, and to a small extent actin, but do not bind antibodies to vimentin or tubulin. Examination of sheets within embryos at the time of embryonic compaction demonstrates that the sheets begin to fragment and disassemble in regions of blastomeres where desmosomes form, but undergo no structural alterations in interior and basal surfaces of the blastomeres. In regions of blastomere - blastomere contact the sheets fragment and associate with granules resembling keratohyalin granules found in keratinocytes. © 1993 Wiley-Liss, Inc.
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    Morphology of nexin links in relation to interdoublet sliding in the sperm flagellum (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 109-118 
    Details
    ISSN: 0886-1544
    Keywords: motility ; flagellum ; spermatozoon ; nexin ; freeze-etch ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this work, we examine whether the “nexin” linkages of the flagellum can extend in length to accommodate interdoublet sliding. Flagellar bends of large angle were induced in bull spermatozoa by hypotonic treatment. It is argued that this produces large interdoublet displacements that are, nevertheless, still within physiological limits. Such flagella were examined by the rapid-freeze, deep-etch techique and the nexin linkages identified by their position in relation to the inner dynein arms and by their straplike, bipartite, morphology. They were found to bridge perpendicularly (or occasionally at an angle) between the A- and B-tubules of adjacent doublets. The nexin linkages were no more than ∼20 nm in length, even in regions in which ∼200 nm of sliding could be inferred. Variable registration between adjacent nexin rows gave some further support to the assumption that sliding had indeed taken place. From this, it is concluded that elastic deformation of the links, such as would accommodate interdoublet sliding, does not occur; some form of displacement must occur between nexin and the adjacent B-tubule. © 1993 Wiley-Liss, Inc.
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    Incorporation of microinjected mutant and wildtype recombinant tropomyosins into stress fibers in fibroblasts (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 119-128 
    Details
    ISSN: 0886-1544
    Keywords: actin ; actin filament assembly ; actin binding sites ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The structural requirements for assembly of tropomyosin into stress fibers were investigated by microinjecting wildtype and four mutant striated chicken muscle α-tropomyosins expressed in E. coli as fusion and nonfusion proteins into cultured rat embryo fibroblasts, followed by localization of tropomyosin using indirect immunofluorescence. The results show that the determinants for stress fiber incorporation in living cells correlate with the in vitro actin affinity of these tropomyosins. Wildtype recombinant protein incorporated into stress fibers both when the amino terminus was unacetylated and when it was blocked with an 80-residue fusion protein [Hitchcock-DeGregori, S.E., and Heald, R.W. (1987): J. Biol. Chem. 262:9730-9735]. The pattern of incorporation was indistinguishable from that of tropomyosin isolated from chicken pectoral muscle. The striated α-tropomyosin incorporated into stress fibers, even though this isoform is not found in nonmuscle cells. Three recombinant mutant tropomyosins in which one-half, two-thirds, or one actin binding site was deleted were tested [Hitchcock-DeGregori, S.E., and Varnell, T.A. (1990): J. Mol. Biol. 214:885-896]. Only the fusion protein with a full actin binding site deleted incorporated into stress fibers. However, the unacetylated, nonfusion proteins with one half and one actin binding site deleted incorporated into stress fibers, consistent with the ability of troponin to promote the actin binding in vitro. A fourth mutant, in which the conserved amino-terminal nine residues were deleted, did not incorporate into stress fibers, consistent with the complete loss of function of this mutant [Cho, Y.J., Liu, J., and Hitchcock-DeGregori, S.E. (1990): J. Biol. Chem. 265:538-545]. © 1993 Wiley-Liss, Inc.
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    Effects of taxol and taxol/hyperthermia treatments on the functional polarization of cytotoxic T lymphocytes (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 129-138 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; MTOC ; centrosome ; pericentriolar material ; cytolytic activity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Immunofluorescence staining, electron microscopy, and (51Cr) cytolytic release assays are used to investigate the effects of taxol and taxol/hyperthermia treatments on the microtubule organization and cytolytic activity of cytotoxic T lymphocytes (CTLs). A 4 h treatment of CTLs with 1 μM taxol results in an extensive reorganization of the microtubule system to form one to a few large microtubule bundles that extend from the centrosome. The Golgi apparatus is not disrupted by this treatment and remains associated with the microtubule organizing centre (MTOC). This microtubule reorganization has no effect on the ability of CTLs to orient their MTOC towards a bound target cell, nor on their cytolytic activity. In control CTLs, not treated with taxol, a mild hyperthermia treatment (42°C, 30 min) results in an aggregation of the pericentriolar material, a loss of MTOC orientation, an inhibition of cytolytic activity, and a disorganization of the microtubule system [Knox et al.: Exp. Cell Res. 194:275-283, 1991]. In contrast, in taxol-treated CTLs the stabilized microtubule bundles are unaffected by such hyperthermia treatment; however, the other effects of hyperthermia appear identical in control and taxol-treated CTLs. These results indicate that a dynamic, radially arranged microtubule array is not required for the functional polarization of CTLs and suggest that a component of the pericentriolar material may play a key role in effecting MTOC orientation. © 1993 Wiley-Liss, Inc.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240301
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    PDGF and neomycin induce similar changes in the actin cytoskeleton in human fibroblasts (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 139-149 
    Details
    ISSN: 0886-1544
    Keywords: growth factor ; phosphatidylinositol cycle ; actin polymerization ; fluorescence microscopy ; cytochalasin D ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The addition of platelet-derived growth factor (PDGF) to serum-starved fibroblasts induces increased motility, formation of lamellipodia, increased ruffling activity, and actin ring structures associated with dorsal ruffles. Involvement of the phosphatidylinositol cycle (PI-cycle) in these morphological changes was investigated by observing the effects of neomycin, an inhibitor of the PI-cycle, on cultured human foreskin fibroblasts. The role of actin in the changes was investigated by using cytochalasin D (CD). Actin in detergent-extracted cells was labelled with TRITC-phalloidin and examined with fluorescence microscopy. Using PDGF and neomycin simultaneously potentiated lamellipodia formation, ruffling activity, as well as the number of cells with actin rings. Furthermore, neomycin by itself induced morphological changes similar to those induced by PDGF. Quantitation of actin rings showed dose and time dependency for PDGF and neomycin respectively, with a maximal number of cells containing rings after 15 min of exposure to either 3.5 mM neomycin or 10 ng PDGF/ml. Comparing the two substances, PDGF induced ring formation in a greater number of cells. These processes were inhibited by the presence of CD. PDGF- and neomycin-induced changes in the actin cytoskeleton were also observed in human embryonic lung fibroblasts, human glial cells, and embryonic mouse fibroblasts, all of which are known to express PDGF-receptors. In conclusion, the present study indicates that an increased turnover of the PI-cycle is not essential for the changes in actin organization induced by PDGF. © 1993 Wiley-Liss, Inc.
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    Divergent neural β tubulin from the antarctic fish notothenia coriiceps neglecta: Potential sequence contributions to cold adaptation of microtubule assembly (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 156-166 
    Details
    ISSN: 0886-1544
    Keywords: tubulin isotypes ; tubulin cDNA sequence ; Antarctic nototheniid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cytoplasmic microtubules of the cold-adapted Antarctic fishes, unlike those of homeotherms and temperate poikilotherms, assemble and function at body temperatures in the range -1.8 to +2°C. To determine whether alterations to the primary sequence of β tubulin may contribute to enhancement of microtubule assembly at cold temperatures, we have cloned and sequenced a 1.8-kilobase neural β-chain cDNA, Ncnβ1, from an Antarctic rockcod, Notothenia coriiceps neglecta. Based on nucleotide sequence homology, Ncnβ1 probably corresponds to a class-II β-tubulin gene. The 446-residue β chain encoded by Ncnβ1 is closely related (sequence homology ∼95%) both to the neural class-I/II isotypes and to the neural/testicular class-IV variants of higher vertebrates, but the sequence of its carboxy-terminal isotype-defining region (residues 431-446) has diverged markedly (≥ 25% change relative to the I/II/IV referents). Furthermore, the NcnβsZ1 polypeptide contains six unique amino-acid substitutions (five conservative, one nonconservative) not found in other vertebrate brain isotypes, and the carboxyterminal region possesses a unique tyrosine inserted at position 442. We conclude that Ncnβ1 encodes a class-II β tubulin that contains sequence modifications, located largely in its interdimer contact domain, that may contribute to cold adaptation of microtubule assembly. © 1993 Wiley-Liss, Inc.
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    Dynamics of microfilaments are similar, but distinct from microtubules during cytokinesis in living, dividing plant cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 151-155 
    Details
    ISSN: 0886-1544
    Keywords: carboxyfluorescein tubulin ; cell plate formation ; confocal microscopy ; phragmoplast ; rhodamine phalloidin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development and dynamics of the phragmoplast cytoskeleton have been analyzed in living stamen hair cells of Tradescantia. Microtubules and actin microfilaments have been identified by microinjecting either carboxyfluorescein labeled brain tubulin or rhodamine phalloidin. Examination with the confocal laser scanning microscope has permitted sequential imaging of the fluorescent cytoskeletal elements in single living cells progressing through division. Phragmoplast microtubules initially emerge through the lateral coalescence of preexisting interzone microtubules. As cytokinesis progresses, these tightly clustered microtubules shorten in length and expand centrifugally toward the cell periphery. By contrast, the phragmoplast microfilaments appear to arise de novo in late anaphase in close association with the proximal surfaces of the reconstituting daughter nuclei. The microfilaments are oriented parallel to the microtubules but conspicuously do not occupy the equatorial region where microtubules interdigitate and where the cell plate vesicles aggregate and fuse. As development proceeds the microfilaments shorten in length and expand in girth, similar to microtubules, although they remain excluded from the cell plate region. In terminal phases of cell plate formation, microtubules degrade first in the central regions of the phragmoplast and later toward the edges, whereas microfilaments break down more uniformly throughout the phragmoplast. © 1993 Wiley-Liss, Inc.
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    Microtubule-associated motility in cytoplasmic extracts of sea urchin eggs (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 167-178 
    Details
    ISSN: 0886-1544
    Keywords: cytoplasmic dynein ; kinesin ; bundling ; crosslinking ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have developed a method for producing sea urchin egg cytoplasmic extracts which support substantial microtubule-associated motility, particularly minus end-directed motility characteristic of cytoplasmic dynein. Particles translocated along microtubules and axonemes predominantly in the minus end direction; microtubules and axonemes glided across the coverslip surface only in the plus end direction (as expected for a minus-end directed motor bound to the coverslip surface); and microtubules crosslinked into bundles in an antiparallel orientation. Velocities of particle and microtubule translocation were in the range of 0.5-1.8 μm/sec. Vanadate at 10 μM inhibited all gliding of the microtubules and axonemes, yet bidirectional particle transport persisted. Vanadate at concentrations of 25 μM and higher inhibited nearly all microtubule-based motility in the preparation and produced parallel bundling of the microtubules. Motility was slowed but not stopped in the presence of 5 mM AMP-PNP.Usually when a particle bound to a microtubule wall, it moved to the microtubule minus end. These particles often remained attached to the minus end. When a microtubule plus end in the shortening phase of dynamic instability reached a stationary particle on the microtubule, sometimes normal minus enddirected motility was activated, or at other times the particle remained attached to the shortening plus end. © 1993 Wiley-Liss, Inc.
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    Control of profilin and actin expression in muscle and nonmuscle cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 179-188 
    Details
    ISSN: 0886-1544
    Keywords: protein synthesis ; northern analysis ; BC3H1 cells ; HepG-2 cells ; C2C12 cells ; profilactin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Profilin is a small G-actin binding protein implicated in sequestering actin monomers in vivo. We have quantitated profilin and actin expression in human hepatoma HepG-2 cells and in two mouse myogenic cell lines, BC3H1 and C2C12, to determine whether the expression of profilin and the expression of nonmuscle isoactin or total actin are co-regulated. During differentiation of both muscle cell types, profilin and nonmuscle actin expression decrease in a coordinate manner as shown by measurements of steady state mRNA and newly synthesized protein. In human hepatoma HepG-2 cells, the twofold increase in actin synthesis observed after 24 hours of exposure to cytochalasin D did not result in an increase in profilin synthesis. Thus, profilin and actin expression are not coregulated in all cells. To determine if there is sufficient profilin to sequester a large portion of cellular G-actin, we measured total profilin and G-actin levels in the three cell types. In each case, profilin accounted for less than 10% of the total G-actin on a molar basis. Thus, profilin is not responsible for total G-actin sequestration in these cells. Finally, using poly-L-proline affinity chromatography, we showed that, in the cell types tested, less than 20% of the poly-L-proline purified profilin existed as a complex with G-actin. The profilin in these cells may be interacting with cellular components other than actin. © 1993 Wiley-Liss, Inc.
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    Microinjection of fluorescent brain tubulin reveals dynamic properties of cortical microtubules in living plant cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 205-213 
    Details
    ISSN: 0886-1544
    Keywords: microtubule dynamics ; cell morphogenesis ; Nitella pseudoflabelatta ; plant cytoskeleton ; Tradescantia virginiana ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescent brain tubulin, injected into living cells of the green alga Nitella pseudoflabellata and the higher plant Tradescantia virginiana, incorporates into the cortical microtubules, allowing these structures to be observed. With confocal laser scanning microscopy, clear images of microtubules were recorded and changes in microtubule patterns documented. After injection, fluorescent lengths of microtubules appeared within a few minutes and their number and length increased rapidly to a “steady state” over the first 15 min. In many instances, fluorescent microtubules could still be detected several hours after injection. In the cells examined, microtubules are arranged as an array of separate units only occasionally displaying close association or accurate co-alignment with neighboring microtubules. In what we perceive to be the steady state condition, some microtubules remain relatively static, while others undergo rapid changes in length or small translocations. We also document what appears to be bidirectional microtubule elongation during postdepolymerization assembly. © 1993 Wiley-Liss, Inc.
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    Myosin-I in mammalian liver (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 189-199 
    Details
    ISSN: 0886-1544
    Keywords: myosin-I ; liver ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Myosin-I refers to a class of proteins with a molecular weight of approximately 110-kDa, which have characteristics of conventional myosin but are unable to form filaments. Previous studies have implicated myosin-I in motile cellular processes including cell migration and phagocytosis. Although the first example of myosin-I in higher eukaryotes was the intestinal 110K-calmodulin complex, which forms in microvilli the lateral links connecting the core bundle of actin filaments to the membrane, myosin-I has now been shown to be a component of rat kidney and to be present in bovine adrenal gland and brain. We have now purified and characterized two polypeptides from rat liver which have several characteristics of the intestinal 110K-calmodulin complex. Both liver polypeptides are solubilized with ATP and co-elute on gel filtration with calmodulin. The polypeptides, of 110-kDa and 130-kDa, bind calmodulin in 1 mM EGTA. Both polypeptides bind to F-actin in an ATP reversible fashion, and crosslink actin filaments. The purified polypeptides possess an actin-activated Mg2+-ATPase activity typical of brush border myosin-I. A polyclonal antiserum directed against the chicken intestinal 110-kDa polypeptide recognizes both rat liver polypeptides, whereas another serum recognizes the 130-kDa but not the 110-kDa rat liver polypeptide. Controlled proteolysis of the purified polypeptides with α-chymotrypsin indicates that the two polypeptides are distinct but related. Immunofluorescence microscopy on isolated hepatocytes shows distribution of myosin-I to be vesicular, distributed throughout the cytoplasm, but more concentrated near the nucleus. These data contribute new evidence by several functional criteria that multiple myosin-I molecules are present in higher organisms and may coexist in a single cell type. © 1993 Wiley-Liss, Inc.
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    Centripetal movement of homologs occurs at the onset of anaphase A in primary oocytes of Ephestia kuehniella Z. (Pyralidae, Lepidoptera) (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 200-204 
    Details
    ISSN: 0886-1544
    Keywords: metaphase ; anaphase ; spindle ; oogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The transition from metaphase to anaphase was examined in primary oocytes of the Mediterranean mealmoth, Ephestia kuehniella. Isolated spindles were analysed using phase-contrast microscopy and antitubulin immunofluorescence. Metaphase I bivalents in female Lepidoptera contain material derived from the synaptonemal complexes, the elimination chromatin, which is located between the homologs. Upon the onset of anaphase I, the homologs detach from the elimination chromatin. The present observations revealed that prior to the start of anaphase A, the homologs move centripetally, i.e., toward the central spindle axis, while the elimination chromatin remains stationary. This type of movement is not directly comparable with conventional chromosome movements such as prometaphase congression, anaphase A, and anaphase B, since it occurs at right angles to the preferential orientation of the spindle MTs. A MT-based mechanism may nevertheless account for the centripetal shift of homologs in meiosis I of the moth: bundling of kinetochore MTs of different chromosomes could transfer the chromosomes toward the spindle axis. Since the homologs move along the poleward surfaces of the plate of elimination chromatin, a MT-independent force producer could exist as well at the interface between the chromosomes and the plate of elimination chromatin. © 1993 Wiley-Liss, Inc.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240401
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    Fimbrin localized to an insoluble cytoskeletal fraction is constitutively phosphorylated on its headpiece domain in adherent macrophages (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 223-233 
    Details
    ISSN: 0886-1544
    Keywords: actin-bundling protein ; phosphorylation ; macrophage fractions ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The actin-bundling protein fimbrin is homologous to l-plastin, a 65kD phosphoprotein expressed in leukocytes and transformed cells [de Arruda et al., J. Cell Biol. 111, 1069-1080]. Because fimbrin is present in cell adhesion sites, we studied the phosphorylation state of fimbrin and its distribution in macrophages sequentially extracted with Triton-X-100 (soluble fraction), Tween 40-deoxy-cholate (cytoskeletal fraction), and SDS (insoluble cytoskeletal fraction). The approximate distribution of fimbrin and actin among these fractions was found to be: 65% fimbrin/55% actin in the soluble fraction, 30% fimbrin/20% actin in the cytoskeletal fraction, and 5% fimbrin/25% actin in the insoluble cytoskeletal fraction. PMA did not alter this distribution. Fluorescence microscopy of acetone-extracted macrophages showed that actin is concentrated in podosomes at the substratum interface and is diffusely distributed throughout the remainder of the cell. Fimbrin colocalizes with actin in podosomes and also exhibits a punctate distribution in the cytoplasm that overlaps with actin. In Tween 40/DOC-extracted cells, podosomes remain, and fimbrin also exhibits a punctate distribution along actin filaments. Metabolic 32PO4 labeling revealed that fimbrin is constitutively phosphorylated and that phosphorylated fimbrin is concentrated in the insoluble cytoskeletal fraction. PMA increased the relative levels of fimbrin phosphorylation twofold but did not alter the pattern of fimbrin fluorescence or the distribution of phosphorylated fimbrin. Limited trypsin digestion and phosphoamino acid analysis demonstrated that phosphorylation occurs specifically on serine residues within the 10kD headpiece domain of fimbrin. Phosphorylation of the headpiece domain could regulate the actin binding and bundling properties of fimbrin, or it could regulate the interaction of fimbrin with other proteins. © 1993 Wiley-Liss, Inc.
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    Motility of intracellular particles in rat fibroblasts is greatly enhanced by phorbol ester and by over-expression of normal p21N-ras (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 254-266 
    Details
    ISSN: 0886-1544
    Keywords: phorbol 12-myristate 13-actate (PMA) ; signal transduction ; sphingosine ; colcemid ; organelles ; video-enhanced microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Particle motility in cultured rat fibroblasts was studied using video-enhanced differential interference contrast microscopy. The average velocity of large bright particles (apparent diameter about 0.5-0.7 μm) was measured in control cells and in cells treated with agents which affected targets related to signal transduction pathways. A Rat-2-derived fibroblast line transfected with a construct containing multiple copies of the N-ras proto-oncogene under the control of dexamethasonesensitive promoter was used as a main experimental model. Dexamethasone treatment was shown to induce high levels of N-ras expression in these cells. This treatment greatly increased the average particle velocity. At the same time dexamethasone did not influence the particle motility in the non-transfected parent cells and in the cells transfected with a construct which did not contain N-ras. Phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC), also induced an approximate eightfold increase in the particle rate after several hours of incubation, while sphingosine, an inhibitor of PKC, prevented this activation. Sphingosine alone reduced the particle motility after a 20 min incubation. The particle movements were inhibited also by colcemid. These data show that the activation of N-ras and PKC produced dramatic activation of microtubule-dependent particle motility. A possible role of this activation in signal-induced alterations of cell morphology is discussed. © 1993 Wiley-Liss, Inc.
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    Localization of CapZ during myofibrillogenesis in cultured chicken muscle (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 317-335 
    Details
    ISSN: 0886-1544
    Keywords: actin ; actin-binding protein ; capping protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Actin filaments undergo dramatic changes in their organization during myofibrilloenesis. In mature skeletal muscle, both CapZ and the barbed end of the actin filaments are located at Z-discs. In vitro, CapZ binds the barbed end of actin filaments and prevents actin subunit addition and loss; CapZ also nucleates actin polymerization in vitro. Taken together, these properties suggest that CapZ may function to organize actin filaments during myofibrillogenesis. We report here that the amount of CapZ in myofibrils from adult chicken pectoral muscle is sufficient to “cap” each actin filament of the sacromere. Double inmmunofluorescence microscopy of skeletal muscle cells in culture was used to determine the spatial and temporal distributions of CapZ relative to actin, α-actinin, titin, and myosin during myofibrilloenesis. Of particular interest was the assembly of CapZ at nascent Z-discs in relation to the organization of actin filaments in nascent myofibrils. In myoblasts and young myotubes, CapZ was diffusely distributed in the cytoplasm. As myotubes matured, CapZ was initially observed in a uniform distribution along non-striated actin filaments called stress fiber-like structures (SFLS). CapZ was observed in a periodic pattern characteristic of mature Z-discs along the SFLS prior to the appearance of a striated staining pattern for actin. In older myotubes, when actin was observed in a pattern characteristic of I-bands, CapZ was distributed in a periodic pattern characteristic of mature Z-discs. The finding that CapZ was assembled at nascent Z-discs before actin was observed in a striated pattern is consistent with the hypothesis that CapZ directs the location and polarity of actin filaments during I-band formation in skeletal muscle cells. The assembly of CapZ at nascent Z-disc structures also was observed relative to the assembly of sarcomeric α-actinin, titin, and thick filaments. Titin and myosin were observed in structures having the organization of mature sarcomeres prior to the appearance of CapZ at nascent Z-discs. The distribution of CapZ and sarcomeric α-actinin in young myotubes was not coincident; in older myotubes, both CapZ and α-actinin were co-localized at Z-discs. In cardiac myocytes, CapZ was detected at Z-discs and was distributed in a punctate pattern throughout the cytoplasm. CapZ also was co-localized with A-CAM and vinculin at cell-cell junctions formed by the myocytes. © 1993 Wiley-Liss, Inc.
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    Microtubule behavior in PC12 neurites: Variable results obtained with photobleach technology (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 345-357 
    Details
    ISSN: 0886-1544
    Keywords: fluorescent analogue cytochemistry ; cytoskeletal transport ; photobleach technology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have examined the effects of various means of photobleaching on the recovery of fluorescene, movement, and morphology of the microtubules in the neurites of rhodamine-tubulin-injected PC12 cells. We find that, depending on power of and time of exposure to the bleaching beam, we can generate at least three different patterns of fluorescence recovery in regenerating PC12 neurites. If bleaching is performed with a relatively low-power beam for an extended period, fluorescence in polymer recovers very little after 1 hours. Under these conditions, however, tubulin immunostaining is seen extending through the bleach zone, and microtubules are present through the bleached zone in thin section electron micrographs. If bleaching is performed with a high-power laster, for 0.5-5 seconds, fluorescence recovery also is quite slow, but electron microscopic observations reveal that no microtubules extend through the bleached region of the neurite, and the uranyl acetate-stained cytoplasm appears more electron lucent than in the unbleached neurite. Finally, if bleaching is performed by very brief exposure to a high-intensity laser beam, resulting in an incomplete reduction of fluorescence intensity through the bleach zone, fluorescence recovery occurs within 20-30 minutes, and immunostained microtubules appear intact through the bleach zone; electron microscopy confirms that microtubules extended through the bleached zone of such neurites. In all three cases, movement of the bleach zone is observed in approximately half of the experimental neurites. These results indicate that highly variable microtubule behaviors can be obtained with photobleach technology, presumably due to different levels and pathways of photodamage generated by different bleach protocols. Nevertheless, it is clear that both turnover and movement of microtubules occur in FC12 neurites, and both are likely to be involved in neurite maintenance and growth. © 1993 Wiley-Liss, Inc.
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    Data fitting in the chemical sciences, Peter Gans, Wiley, Chichester, 1992, ISBN 0471934127, 258 pp., £29.95 (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 75-76 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070106
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    Chemical structure systems, Computational Techniques for Representation, Searching and Processing of Structural Information, ed. by Janet E. Ash, Wendy A. Warr and Peter Willett, Ellis Horwood, Chichester, 1991, ISBN 0-13-12669-3, 351 pp., £39.50 (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 223-224 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070308
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    Application of orthogonal expansion to mapping and modelling (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 243-253 
    Details
    ISSN: 0886-9383
    Keywords: Orthogonal expansion ; Mapping ; Modelling ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper we discuss the orthogonal expansion of data matrices and its application to mapping and modelling. Two new methods, modified optimal discriminant plane (MODP) for mapping and order Gram-Schmidt orthogonalization (OGSO) for modelling, are proposed and examples are given.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070501
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    Assessment of the effective rank of a (co)variance matrix: A non-parametric goodness-of-fit test (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 381-392 
    Details
    ISSN: 0886-9383
    Keywords: Factor analysis ; Kolmogorov-Smirnov test ; Non-parametric tests in factor analysis ; Non-parametric test for principal components ; Principal component analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Each eigenvector of the dispersion matrix [X]T [X] was shown to be a partial predictor of the original data matrix [X], the sum of the predictions from the individual principal components being equal to the expectance of [X]. By comparing the distributions of the members of two neighbouring predicted matrices, [X̃]1…i and [X̃]1…i+1 (i.e. the sums of the first i and i + 1 individual predictions respectively), it was shown that they should be indistinguishable provided that i is equal to or greater than the effective rank of [X], and significantly different otherwise. This was confirmed by analysing the visible absorption spectra of methyl orange and methyl red solutions as well as the Raman spectra of Na2SO4 and MgSO4 solutions. On the grounds of these findings, a non-parametric goodness-of-fit test for assessing the effective rank of [X] was proposed which proved to be comparatively conservative and more robust than most currently used tests.
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    Constrained background bilinearization with a generalized simulated annealing algorithm (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 369-379 
    Details
    ISSN: 0886-9383
    Keywords: Simulated annealing ; Constrained background bilinearization ; Calibration ; Two-way bilinear data ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Generalized simulated annealing (GSA) is an optimization technique for locating the global optimum. In this paper GSA was used as the optimization procedure in the constrained background bilinearization (CBBL) of two-way bilinear data in order to reduce the possibility of sinking into local optima. The behaviour of the algorithm and its comparison with the modified Powell algorithm were studied by simulations and real fluorescence excitation-emission data for organic dye mixtures.
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    Comments on the residual bilinearization method (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 439-445 
    Details
    ISSN: 0886-9383
    Keywords: Calibration ; Rank annihilation ; Residual bilinearization ; Three-way ; Trilinear ; Net analyte rank ; Second-order ; Generalized rank annihilation method (GRAM) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Through theoretical analysis and computer simulation, this short communication comments on the residual bilinearization (RBL) method and compares it with non-bilinear rank annihilation (NBRA) for the treatment of second-order calibration with non-bilinear data. It is found that these two methods are mathematically equivalent but have different noise propagation properties. The second-order advantage, namely quantitation in the presence of unknown interferences, can be carried over to non-bilinear data only if there exists a net analyte rank (NAR) for the analyte of interest.
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    URL: http://dx.doi.org/10.1002/cem.1180070508
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    Standard errors in the eigenvalues of a cross-product matrix: Theory and applications (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 495-526 
    Details
    ISSN: 0886-9383
    Keywords: Standard errors ; Eigenvalues ; PCA ; MLR ; GRAM ; Rank estimation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New expressions are derived for the standard errors in the eigenvalues of a cross-product matrix by the method of error propagation. Cross-product matrices frequently arise in multivariate data analysis, especially in principal component analysis (PCA). The derived standard errors account for the variability in the data as a result of measurement noise and are therefore essentially different from the standard errors developed in multivariate statistics. Those standard errors were derived in order to account for the finite number of observations on a fixed number of variables, the so-called sampling error. They can be used for making inferences about the population eigenvalues. Making inferences about the population eigenvalues is often not the purposes of PCA in physical sciences. This is particularly true if the measurements are performed on an analytical instrument that produces two-dimensional arrays for one chemical sample: the rows and columns of such a data matrix cannot be identified with observations on variables at all. However, PCA can still be used as a general data reduction technique, but now the effect of measurement noise on the standard errors in the eigenvalues has to be considered. The consequences for significance testing of the eigenvalues as well as the usefulness for error estimates for scores and loadings of PCA, multiple linear regression (MLR) and the generalized rank annihilation method (GRAM) are discussed. The adequacy of the derived expressions is tested by Monte Carlo simulations.
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    Software Review (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 559-566 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070101
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    Compression of nth-order data arrays by B-splines. Part 1: Theory (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 61-73 
    Details
    ISSN: 0886-9383
    Keywords: Compression ; Multivariate analysis ; B-splines ; Maximum entropy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For efficient handling of very large data arrays, pretreatment by compression is mandatory. In the present paper B-spline methods are described as good candidates for such data array compression. The mathematical relation between the maximum entropy method for compression of data tables and the B-spline of zeroth degree is described together with the generalization of B-spline compression to nth-order data array tables in matrix and tensor algebra.
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    Investigation of copper(II)-Ethylenediaminetetraacetate complexation by window factor analysis of ultraviolet spectraPresented at the Eastern Analytical Symposium in Somerset, NJ on 14 November 1992 (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 89-98 
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    ISSN: 0886-9383
    Keywords: Factor analysis ; Window factor analysis ; Multicomponent analysis ; Ultraviolet spectroscopy ; Cu(II) complexes ; Ethylenediaminetetraacetic acid ; EDTA ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Window factor analysis (WFA) is a self-modeling chemometric technique for obtaining the concentration profiles of components from evolutionary processes such as chromotography, titration and reaction kinetics. By specifying the ‘window’, i.e. the region along the evolutionary axis indigenous to a component, the concentration profile of the component can be obtained without recourse to any information concerning the other components. Mathematical expressions required to perform such computations are derived. The method is applied to the investigation of copper(II) complexation with ethylenediaminetetraacetate (EDTA) by recording and factor analyzing the ultraviolet spectra of aqueous solutions containing a fixed amount of the disodium salt of EDTA and varying amounts of CuCl2. Evidence for four different species of EDTA is obtained. Clues concerning the stoichiometry of the species are garnered from the concentration profiles.
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    Short communication Classification methods for multivariate quality parameters (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 131-142 
    Details
    ISSN: 0886-9383
    Keywords: Classification ; Discriminant analysis ; Class modeling ; Specification limits ; Cross-validation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: There are many chemical products where product conformity is decided upon by qualitative human judgements of overall product quality. Nowadays, quantitative instrumentally determined quality parameters become available which are intended to replace such qualitative judgements by means of automatic decision rules using multivariate specification limits. Six classification methods to derive such limits are compared in terms of their power to predict corresponding human judgemets on overall color conformity of 17 dyestuffs based on historical quality data. Standard statistical classification methods turned out to be unacceptable for the routine generation of decision rules because of the frequent distinct suboptimality of their predictive power. Instead, a simple non-statistical classification method utilizing a priori knowledge about the underlying data structure yielded uniformly satisfactory decision rules.
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    A global perspective on multivariate calibration methods (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 153-163 
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    ISSN: 0886-9383
    Keywords: Generalized inverse ; K-matrix analysis ; P-matrix analysis ; Least squares ; Principal component regression ; Partial least squares ; Continuum regression ; Beer's law ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper consists of two distinct but related parts. In the first part a geometric theory of generalized inverses is presented and a methodology based on this theory is developed and applied to solve the K-matrix and P-matrix forms of Beer's law. It is shown that most currently accepted and practiced methods for solving these forms of Beer's law are just special cases of this geometric theory of generalized inverses. In addition, this geometric theory is used to explain why the current methods work and why they fail.In the second part a general methodology that includes as special cases least squares, principal component regression, partial least squares 1 and 2, continuum regression plus a variety of other described and undescribed methodologies is presented and then applied to solve the P-matrix formulation of Beer's law. This general methodology, like the first, is also geometric in nature and relies on an understanding of projections.The main emphasis of this paper is one of perspective, which, if understood, provides the proper foundation for answering the general but extremely hard and possibly unanswerable question “what is the best method?”.
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    Detecting and adjusting for non-linearities in calibration of near-infrared data using principal components (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 195-212 
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    ISSN: 0886-9383
    Keywords: Calibration ; Non-linearity ; Principal components ; Stein estimate ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new regression method for non-linear near-infrared spectroscopic data is proposed. The technique is based on a model which is linear in the principal components and simple functions (squares and products) of them. Added variable plots are used to determine which squares and products to incorporate into the model. The regression coefficients are estimated by a Stein estimate which shrinks towards the estimate determined by the first several principal components and the selected non-linear terms. The technique is not computationally intensive and is appropriate for routine predictions of chemical concentrations. The method is tested on three data sets and in all cases gives more accurate predictions than does linear principal components regression.
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    URL: http://dx.doi.org/10.1002/cem.1180070306
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    Non-linear mapping for structure-activity and structure-property modelling (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 227-242 
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    ISSN: 0886-9383
    Keywords: Non-linear mapping ; Graphical methods ; SAR ; SPR ; Quality of representation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: From a review of the theoretical aspects of non-linear mapping and the different algorithms available in the literature, the methodological and practical problems linked to the use of this multivariate method in structure-activity and structure-property relationship studies are underlined. Useful tools for the graphical display of the outputs and the interpretation of the obtained clusters are presented. Statistical parameters estimating the quality of the graphical representation of each individual are also introduced. An example of application on a data matrix of 37 acaricides described by four physicochemical descriptors (π, F, R, MR) is presented.
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    A test of significance for partial least squares regression (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 291-304 
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    ISSN: 0886-9383
    Keywords: Partial least squares ; Monte Carlo methods ; Cross validation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Partial least squares (PLS) regression is a commonly used statistical technique for performing multivariate calibration, especially in situations where there are more variables than samples. Choosing the number of factors to include in a model is a decision that all users of PLS must make, but is complicated by the large number of empirical tests available. In most instances predictive ability is the most desired property of a PLS model and so interest has centred on making this choice based on an internal validation process. A popular approach is the calculation of a cross-validated r2 to gauge how much variance in the dependent variable can be explained from leave-one-out predictions. Using Monte Carlo simulations for different sizes of data set, the influence of chance effects on the cross-validation process is investigated. The results are presented as tables of critical values which are compared against the values of cross-validated r2 obtained from the user's own data set. This gives a formal test for predictive ability of a PLS model with a given number of dimensions.
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    Optimization in organic synthesis. An approach to obtaining kinetic information by sequential response surface modelling. Outline of the principles (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 341-367 
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    ISSN: 0886-9383
    Keywords: Reaction kinetics ; Initial rate ; Kinetic order ; Response surface modelling ; Canonical analysis ; Organic synthesis ; Optimization ; Reaction mechanisms ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is presented by which it is possible to estimate the initial rate of chemical reactions when the experimental conditions are varied according to a response surface design. The method is intended as a complementary method for analysing data obtained from experiments in synthetic chemistry when the objective is to optimize the yield of the reaction.Data obtained by simulations have been used to develop the method. From the simulated reactions it is shown that sequential analysis of the chemical yield of the reaction makes it possible to estimate models which describe how the parameters of the response surface of the yield vary over time. The derivatives of these time functions of the response surface parameters can be used to define a rate function which describes how the variations in the experimental conditions influence the rate of the reaction.It is shown how such rate functions can be used to afford reasonable estimates of the initial rates of the reaction. The initial reaction rates thus estimated can be used to determine the kinetic order of the reactants and also to provide estimates of the activation energy of the reaction.A thorough discussion of how canonical analysis of the rate function may assist in the elucidation of reaction mechanisms is given.
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    Multivariate selection of variables in industrial quality control: Optimizing aviation fuel final control (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 427-438 
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    ISSN: 0886-9383
    Keywords: Quality control ; Kerosene ; Variable reduction ; Cross-validation ; Variable selection ; Procrustes rotation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper deals with a typical question encountered in all industrial analytical laboratories: are all the tests performed in the laboratory to characterize the final product really necessary? In this work the cross-validation technique, Procrustes rotation techniques and statistical variable selection have been used to reduce the 26 initial British Petroleum and ASTM kerosene specification test to ten ‘essential’ ones. Statistical as well as chemical considerations were used to select the optimum subset of original variables to be retained from all the possible ones.
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    EDITORIAL (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 453-454 
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    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070602
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    Robust principal component analysis by projection pursuit (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 527-541 
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    ISSN: 0886-9383
    Keywords: Principal component analysis ; Projection pursuit ; Simulated annealing algorithm ; Robust statistics ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Principal component analysis (PCA) is a widely used technique in chemometrics. The classical PCA method is, unfortunately, non-robust, since the variance is adopted as the objective function. In this paper, projection pursuit (PP) is used to carry out PCA with a criterion which is more robust than the variance. In addition, the generalized simulated annealing (GSA) algorithm is introduced as an optimization procedure in the process of PP calculation to guarantee the global optimum. The results for simulated data sets show that PCA via PP is resistant to the deviation of the error distribution from the normal one. The method is especially recommended for use in cases with possible outlier(s) existing in the data.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240101
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    Immunological comparison of 22S, 19S, and 12S dyneins from Paramecium cilia (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 17-28 
    Details
    ISSN: 0886-1544
    Keywords: antibody ; motility ; axoneme ; ATPase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Three forms of dynein (22S, 19S, and 12S) were purified from Paramecium cilia. Two classes of monoclonal antibodies against purified 22S dynein were generated. One class reacted on immunoblots with the heavy chains of 22S, 19S, and 12S dyneins; the second class reacted with an 88 kD intermediate chain of 22S dynein. Polyclonal antiserum to the heavy chains of 22S dynein reacted with the γ-heavy chain of 22S and 19S dyneins. A previously described antiserum raised against 22S dynein [Travis et al.: Biochim. Biophys. Acta 966:73-83, 1988] recognized the γ-heavy chain of 22S dynein which was also present in 19S and 12S dyneins, along with the 88 and 76 kD intermediate chains of 22S dynein. This antiserum was also able to immunoprecipitate dynein from crude extracts of cilia.Electron microscopy revealed that the 22S dynein consisted mainly of two-headed particles with some three-headed particles present. The 12S dynein was mainly one-headed particles. The 19S dynein was a mixture of three-, two-, and one-headed particles. The immunological and electron microscopic studies showed that 19S dynein arises from 22S dynein, and that 12S dynein is heterogeneous, composed of the γ-heavy chain of 22S dynein and a unique dynein ATPase.The polyclonal antibodies were also used to detect cross-reactive proteins in other organisms. Both the anti-heavy chain and the anti-22S dynein sera reacted strongly with 22S outer arm dynein of Tetrahymena, but not with the 14S dynein of this organism. © 1993 Wiley-Liss, Inc.
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    Ciliary dynein of Paramecium tetraurelia: Photolytic maps of the three heavy chains (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 29-38 
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    ISSN: 0886-1544
    Keywords: vanadate ; vanadate-mediated photolysis of dynein ; ATP-binding domain of dynein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ciliate Paramecium tetraurelia presents a powerful system to define the structural basis for dynein functional diversity within a single cell. This analysis will depend on the biochemical resolution of the dynein proteins. As an important first step, the three heavy chains of the ciliary outer arm dynein of paramecium were characterized. Sucrose density gradient centrifugation in a high salt buffer separated the dynein into a 22S species, which contained the α and β heavy chains, and a 12S species, which contained the α chain as well as the inner arm dynein heavy chains. Both the 22S and 12S species retained enzymatic latency as indicated by stimulation of MgATPase activity by 0.1% Triton X-100. An unusual ATP-independent V1-like photolysis of only the β chain provided the basis for estimating that the β chain contributes almost half of the 22S MgATPase activity that is susceptible to V1 photolysis. The combination of the density gradient separation of the partially dissociated dynein and the ATP-independent V1-like photolysis of only the β chain led to the unambiguous assignment of the V1 photolytic products to the appropriate parent heavy chains. An estimate of the molecular sizes of the three heavy chains was obtained. The photolytic peptide maps, which define the ATP-binding domains, were determined for the three heavy chains. © 1993 Wiley-Liss, Inc.
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    Steric inhibition of cytoplasmic dynein and kinesin motility by MAP2 (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 1-16 
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    ISSN: 0886-1544
    Keywords: cytoplasmic dynein ; kinesin ; microtubules ; motility ; MAPs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using several in vitro motility assays, we found that motility driven by the microtubule (MT) motors, kinesin and cytoplasmic dynein, could be inhibited by MAP2 but not by tau protein or the MT-binding proteolytic fragment of MAP2.In MT gliding assays, even the presence of one MAP2 molecule per sixty-nine tubulin dimers caused an inhibition of about 75% of MT motility at low concentrations of both motors. The percent inhibition of motility decreased with increasing concentration of either motor, suggesting that the inhibition was the result of competition for access to the MT surface. The decrease in the number of moving MTs with MAP2 was correlated with an increase in the frequency of release of moving MTs from the motor-coated glass. In assays of in vitro vesicular organelle motility and formation of ER networks, the presence of MAP2 inhibited small vesicle movements and to a lesser extent ER network formation.To determine if competition for specific sites on the MT or coating of the MT surface inhibited motility, we used tau protein and the chymotryptic MT-binding fragments of MAP2 to coat MTs. No inhibition was observed and there was even an increase in the number of attached and moving MTs in the gliding assay with tau-coated MTs. Because MAP2, tau and the chymotryptic MT-binding fragments of MAP2 bind to the same domain on tubulin, masking of the MT surface sites does not appear responsible for the inhibition of motility by MAP2. Rather, we suggest that the sidearm of MAP2 interfered with the interaction of motors with MTs and caused a dramatic increase in the rate of MT release. In vivo, MAP2 could play a major role in the generation of cellular polarity even at substoichiometric levels by inhibiting transport on microtubules in specific domains of the cytoplasm. © 1993 Wiley-Liss, Inc.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993) 
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    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    Site-directed antibodies to tubulin (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 1-6 
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    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    Myosin heavy chain dephosphorylation during cytokinesis in dividing sea urchin embryos (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 369-380 
    Details
    ISSN: 0886-1544
    Keywords: myosin heavy chain ; cytokinesis ; dephosphorylation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Myosin heavy chain (MHC) phosphorylation was examined throughout the period of first cleavage in developing sea urchin embryos. MHC was found to be phosphorylated in these cells and, furthermore, the relative state of myosin phosphorylation was found to decrease as cells progressed through cytokinesis. Following the completion of cytokinesis, the relative state of MHC phosphorylation returned to levels observed in precytokinesis cells. The above results were obtained with myosin immunoprecipitated from whole cell lysates. In order to specifically examine the phosphorylation, state of MHC in the cleavage furrow, a protocol was developed for the isolation of intact contractile rings from dividing sea urchin embryos. MHC was immunoprecipitated from isolated contractile rings and the relative phosphorylation state of this MHC was compared with that of MHC isolated from whole cell lysates prepared at the same time. MHC from isolated contractile rings was found to be significantly less phosphorylated than total cellular MHC, suggesting a role for MHC dephosphorylation during cytokinesis. © 1993 Wiley-Liss, Inc.
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    Dynamics of organelles in the mitotic spindles of living cells: Membrane and microtubule interactions (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 19-39 
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    ISSN: 0886-1544
    Keywords: endoplasmic reticulum ; carbocyanine dyes ; mitosis ; cell division ; membranous organelles ; confocal microscopy ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution and dynamics of the membranous organelles in two cell types were investigated during cell division. Live cells (either PtK2 or LLC-PK1) labeled with the vital dye 3,3′-dihexyloxacarbocyanine iodide [DiOC6(3)] were observed via serial optical sectioning with the laser-scanning confocal microscope. Z-series of labeled, dividing cells were collected every 1-2 minutes throughout mitosis, beginning at prophase and extending to the spreading of the daughter cells. Membrane distribution began to change from the onset of prophase in both cell types. When the mitotic spindle formed in prometaphase, fine tubular membranes, similar to those extending out to the edges of interphase cells aligned along the kinetochore spindle fibers. The lacy polygonal network typical of interphase cells persisted beneath the spindle, and a membrane network was also associated with the dorsal layer of the cell. As PtK2 cells reached metaphse, their spindles were nearly devoid of membrane staining, whereas the spindles of LLC-PK1 cells contained many tubular and small vesicular membranous structures. X-Z series of the LLC-PK1 metaphase spindle revealed a small cone of membranes that was separated from the rest of the cytoplasm by kinetochore MTs. In both cell types, as chromosome separation proceeded, the interzone remained nearly devoid of membranes until the onset of anaphase B. At this time the elongating interzonal microtubules were closely associated with the polygonal network of endoplasmic reticulum. Cytokinesis caused a compression, and then an exclusion of organelles from the midbody. Immunofluorescence staining with anti-tubulin antibodies suggested that spindle membranes were associated with microtubules throughout mitosis. In addition, taxol induced a dense and extensive collection of small vesicles to collect at the spindle poles of both cell types. Nocodazole treatment induced a distinct loss of organization of the membranous components of the spindles. Together these results suggest that microtubules organize the membrane distribution in mitotic cells, and that this organization may vary in different cell types depending on the quantity of microtubules within the spindle. © 1993 Wiley-Liss, Inc.
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    Computerized analysis of tumor cells flowing in a parallel plate chamber to determine their adhesion stabilization lag time (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 88-98 
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    ISSN: 0886-1544
    Keywords: transglutaminase ; melanoma ; digital image analysis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The importance of cell adhesion in a variety of physiological phenomena requires development of an understanding of the factors and molecular mechanisms underlying these behaviors. Cell adhesion is a multistep process involving primary receptor-ligand interactions followed by secondary events that may lead to the formation of focal contacts. Due to the lack of well-defined assays to study adhesion stabilization, little is known about this process, except that it may involve signaling events, receptor recruitment, and, as we have demonstrated, covalent peptide cross-linking by cell membrane-associated transglutaminase [Menter et al.: Cell Biophys. 18:123-143, 1992]. To study the stabilization process we have developed a dynamic assay employing a parallel plate flow chamber coupled with video microscopy and digital image processing. Our studies utilize wheat germ agglutinin-selected human metastatic melanoma cell variants that exhibit differences in their experimental metastatic potential and expression of transglutaminase. Using this assay, quantifying cell-substrate stabilization was found to be quick, reliable, reproducible, and useful in evaluating agents that block this process. © 1993 Wiley-Liss, Inc.
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    Rat liver fat-storing cell lines express sarcomeric myosin heavy chain mRNA and protein (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 125-132 
    Details
    ISSN: 0886-1544
    Keywords: lipocytes ; liver cirrhosis ; myofibroblasts ; myosin gene ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fat-storing cells (FSC, lipocytes, or Ito cells) of liver store vitamin A and are the main producers of extracellular matrix in normal and cirrhotic liver. During liver injury, FSC undergo an activation process characterized by a decrease in vitamin A storage and an increase in cell proliferation and extracellular matrix deposition. This activation process also occurs upon culturing FSC from normal liver. In contrast to most cells of nonmuscle origin, activated FSC express two cytoskeletal proteins normally found in muscle, desmin, and smooth muscle α-actin. Based on their strategic perisinusoidal location, it has been hypothesized that FSC play a role in regulating blood flow. However, the nature of the contractile elements involved in this process remains to be determined. In this communication we demonstrate the presence of a sarcomeric myosin in proteins solubilized from liver biomatrix. In addition we demonstrate the expression of sarcomeric myosin heavy chain (MHC) mRNA and protein in two FSC clones derived from a CCl4-cirrhotic rat liver (CFSC). Through cloning the cDNA corresponding to the MHC gene expressed in these cells we demonstrate that it encodes fast IId skeletal MHC and thus represents a marker normally seen in adult muscle. The unexpected expression of an adult stage skeletal muscle molecular motor in FSC from cirrhotic liver is consistent with the proposed specialized contractile capacity of these cells. © 1993 Wiley-Liss, Inc.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260301
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    Disorganization of microfilaments and intermediate filaments interferes with the assembly and stability of desmosomes in MDCK epithelial cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 163-180 
    Details
    ISSN: 0886-1544
    Keywords: intercellular junctions ; desmosome ; assembly ; MDCK ; epithelia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To investigate the possible role(s) of cytoskeletal elements in desmosome assembly we have studied the effects of cytostatic drugs on the assembly of desmosomes in MDCK epithelial cells. We showed previously [Pasdar et al.: Cell Motil. Cytoskeleton 23:201-213, 1992] that selective disruption of microtubules has no effect on desmosome assembly. Here, we have treated MDCK cells with cytochalasin B and a combination of cytochalasin B and nocodazole and analysed the effects on desmosome assembly. Immunofluorescence analysis of MDCK cultures following drug treatment indicated complete disruption of actin microfilaments and disorganization of cytokeratin intermediate filaments. Biochemical analysis of newly synthesized desmosomal membrane core glycoproteins as well as the cell adhesion proteir. E-cadherin revealed no effect of these drugs on the kinetics of synthesis, intracellular processing, or transport to the plasma membrane either in the presence or absence of cell-cell contact. However, morphological analyses revealed a significant disruption in the spatial organization of desmosomal proteins and E-cadherin. Drug treatment in the absence of cell-cell contact resulted in the disruption of the normally observed homogenous punctate staining pattern and appearance of aggregate staining. Induction of cell-cell contact in these cultures resulted in redistribution of some of the aggregate staining to the plasma membrane. In contrast to control cultures, significant amount of intracellular staining was retained for all desmosomal proteins. Biochemical analyses of turnover rates of newly synthesized desmosomal proteins indicated a significant decrease in metabolic stability of these proteins while the turnover rate of E-cadherin was not significantly different among control and drug-treated cultures. Taken together, these results suggest that intact actin and cytokeratin filaments are necessary for the stability, efficient assembly, and spatial organization of the junctional components at the membrane. The regulatory role of cytokeratins and actin filaments in assembly and stability of desmosomes on the plasma membrane is discussed. © 1993 Wiley-Liss, Inc.
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    gCap39 is a nuclear and cytoplasmic protein (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 227-238 
    Details
    ISSN: 0886-1544
    Keywords: gelsolin ; actin binding proteins ; filament end capping ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: gCap39 is a newly identified member of the Ca2+- and polyphosphoinositidemodulated gelsolin family of actin binding proteins which is different from gelsolin in several important respects: it caps filament ends, it does not sever filaments, it binds reversibly to actin, it is phosphorylated in vivo, and it is also present in the nucleus. gCap39 and gelsolin coexist in a variety of cells. To better understand the roles of gCap39 and gelsolin, we have compared their relative amounts and intracellular distributions. We found that gCap39 is very abundant in macrophages (accounting for 0.6% of total macrophage proteins), and is present in 12-fold molar excess to gelsolin. Both proteins are highly induced during differentiation of the promyelocytic leukemia cell line into macrophages. gCap39 is less abundant in fibroblasts (0.04% total proteins) and is present in equal molar ratio to gelsolin. The two proteins are colocalized in the cytoplasm, but gCap39 is also found in the nucleus while gelsolin is not. Nuclear gCap39 redistributes throughout the cytoplasm during mitosis and is excluded from regions containing chromosomes. Our results demonstrate that gCap39 is a nuclear and cytoplasmic protein which has unique as well as common functions compared with gelsolin. © 1993 Wiley-Liss, Inc.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260401
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    Unambiguous classification of microtubule-ends in vitro: Dynamic properties of the plus- and minus-ends (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 282-290 
    Details
    ISSN: 0886-1544
    Keywords: DIC microscopy ; dynamic instability ; kinesin ; microspheres ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To understand the mechanism of dynamic instability of microtubule growth and shortening, one needs a means of reliably determining the polarity of the microtubules under investigation. Sea urchin sperm-tail axonemal fragments nucleate the growth of both plus-ended and minus-ended microtubules, but their polarity is not apparent by video-enhanced DIC microscopy. The polarity of a microtubule is usually assessed by observing differences between the rates and lengths of growth and shortening excursions of the two ends. In practice, though, a significant fraction of the population of microtubules displays characteristics intermediate between the average characteristics of either end, thereby escaping classification. Excluding these “intermediate” microtubules from the measured populations introduces bias into the understanding of microtubule dynamic instability. We circumvent this problem by making use of the plus-end directed movement of the microtubule-dependent molecular motor kinesin to determine the polarity of any given microtubule unambiguously. Carboxylated-microspheres coated with kinesin, which are clearly visible by DIC microscopy, were used to determine the polarity of a microtubule. The dynamics were then observed. Kinesin was found to have no marked effect on dynamic instability. By this technique, we show that the distributions of properties that describe microtubule dynamic instability (rates and lengths of growth and shortening as well as frequencies of interconversion between these phases) of plus-ends overlap to a significant extent with those of minus-ends. It is this overlap that obscures the usual classification of the ends. Therefore, models describing microtubule dynamic instability need to incorporate the broad and overlapping range of properties of the two ends. © 1993 Wiley-Liss, Inc.
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    CENP-F is a ca 400 kDa kinetochore protein that exhibits a cell-cycle dependent localization (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 214-226 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; autoantibodies ; kinetochore ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have identified a novel .ca 400 kDa cell-cycle dependent kinetochore associated protein in human cells, designated CENP-F, using human autoimmune serum. Immunofluorescence staining using the native serum, affinity purified antibodies, or antibodies raised against a cloned portion of CENP-F first reveals CENP-F homogeneously distributed throughout the nucleus of HeLa cells in the G2 stage of the cell cycle. Progression into prophase is accompanied by the localization of CENP-F to all the kinetochore regions of the karyotype. Kinetochore association is maintained throughout metaphase, but at the onset of anaphase CENP-F is no longer detected in association with the kinetochore but is found at the spindle mid-zone. By telophase, it is concentrated into a narrow band on either side of the midbody. Studies of the interaction of CENP-F with the kinetochore indicate that this protein associates with the kinetochore independent of tubulin and dissociation is dependent on events connected with the onset of anaphase. Nuclease digestion studies and immunoelectron-microscopy indicate that CENP-F is localized to the kinetochore plates and specifically to the outer surface of the outer kinetochore plate. The distribution of CENP-F closely parallels that of another high molecular weight kinetochore associated protein, CENP-E. Comparative studies indicate that there are antibodies in the CENP-F reactive autoimmune serum that recognize determinants present in the central helical rod domain of CENP-E. Immune depletion experiments confirm that CENP-F exhibits the distribution pattern in cells that was seen with the native autoimmune serum. © 1993 Wiley-Liss, Inc.
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    Regulation of microtubule dynamic instability (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 275-281 
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    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250101
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    Microtubules, ribosomes, and RNA: Evidence for cytoplasmic localization and translational regulation (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 1-9 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1002/cm.970250102
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    Elastic properties of titin filaments demonstrated using a “freeze-break” technique (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 274-283 
    Details
    ISSN: 0886-1544
    Keywords: immunoelectron microscopy ; rabbit psoas ; elasticity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A “freeze-break” technique (Trombitás, K.: Acta Biochim. Biophys. Hung. 6:419-427, 1971) and immunoelectron microscopy were used to study the elastic properties of titin filaments. Small bundles of freshly prepared rabbit psoas muscle fibers were quickly frozen and broken under liquid nitrogen to fracture sarcomeres in planes perpendicular to the filament axis, in each of various regions along the sarcomere. The still-frozen specimens were thawed during fixation to allow elastic filaments to retract. The broken specimens were then labelled with monoclonal anti-titin antibodies against an unique epitope in the I-band.The titin epitopes were normally positioned symmetrically about the Z-line. However, in sarcomeres broken at the A-I junction, the epitopes no longer remained symmetrical: the titin filaments in the broken half-sarcomere retracted, independently of the thin filaments, forming a dense band just near the Z-line. The retracted density apparently did not reach the Z-line; retraction stopped at the level of the so-called N1-line. In sarcomeres broken at the Z-line level, the titin filaments retracted in the opposite direction. In this case the titin epitope retracted all the way to the ends of the thick filaments.It appears then that titin molecules form elastic filaments that are independent of thin filaments in most of the I-band. Near the Z-line, however, the titin filaments either have an inelastic domain or associate firmly with the thin filaments at the N1-line level. © 1993 Wiley-Liss, Inc.
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    Ultrastructure and immunocytochemistry of the isolated human erythrocyte membrane skeleton (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 30-42 
    Details
    ISSN: 0886-1544
    Keywords: spectrin ; cytoskeleton ; erythrocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Isolated skeletons from human erythrocyte ghosts were studied using immunogold labeling; negative staining; and quick-freeze, deep-etch, rotary replication with Pt/C (QFDERR). Isolated skeletons visualized by QFDERR were similar to the negatively stained skeletons in that the proteins spectrin, actin, and ankyrin could be easily distinguished. However, the quick-frozen skeletons had two fewer filaments (4.2 ± 0.7) at an actin junction. Immunogold labeling of skeletons with site-specific spectrin antibodies not only confirmed the designation of these filaments as spectrin molecules, but indicated that about 30% of spectrin filaments form non-actin junctions consistent with the hexameric organization of these filaments. Many of the filaments displayed a striking banding pattern indicative of underlying substructure. Isolated skeletons prepared by QFDERR also showed evidence of laterally associated spectrin filaments. These associations, as well as many hexamer junctions, are lost during negative staining. Negative staining also apparently caused ∼21% of the spectrin filaments to separate into their monomeric subunits. These results indicate that the surface tension imposed during negative staining of isolated skeletons can cause a loss of interactions normally present in the intact membrane skeleton. © 1993 Wiley-Liss, Inc.
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    βIV is the major β-tubulin isotype in bovine cilia (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 19-29 
    Details
    ISSN: 0886-1544
    Keywords: photoreceptor ; retina ; cilium ; trachea ; microtubules ; immunocytochemistry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Four different isotypes of β-tubulin are known to be expressed in mammalian brain. Monoclonal antibodies against βII, βIII, and βIV were used to characterize the β-tubulin isotypes in two ciliated bovine tissues: non-motile sensory cilia of retinal rod cells and motile cilia of tracheal epithelium. Retinal rod outer segment (ROS) connecting cilia and cytoskeletons were purified by density gradient centrifugation. This preparation contained more than 20 major protein protein components, as shown by dodecyl sulfate polyacrylamide gel electrophoresis. Electroblots were used to quantitate the relative amounts of βII, βIII, and βIV. The connecting cilium and cytoskeleton of the rod outer segment has less type III β-tubulin than brain and more type IV. The ratio of βIV to βII in the ROS is nearly a factor of 8 larger than in brain. Electron microscopic immunocytochemistry showed extensive labeling of cilia by anti-type IV in thin sections of retinas and trachea, and also in purified ROS cilia and cyoskeletons. Labeling of cilia by anti-βII was also observed, although in the purified ROS cilia and cytoskeleton, the anti-βII labeling was primarily on amorphous non-ciliary material. The results suggest that both motile and non-motile cilia are enriched in the type IV β-tubulin subunit. © 1993 Wiley-Liss, Inc.
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    Colchicine-induced stimulation of PMN motility related to cytoskeletal changes in actin, α-actinin, and myosin (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 10-18 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; blebs ; locomotion ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Colchicine-induced stimulation of polymorphonuclear leukocyte (PMN) locomotion is an interesting model because extension of blebs at the front occurs at a rate (about 2.4 μm/s) which is far above that reported for growth of actin filaments. The following cytoskeletal changes were observed in colchicine-treated PMNs: (1)a small increase in cytoskeleton-associated actin was noted, as well as a somewhate more pronounced increase in cytoskeleton-associated α-actinin, as compared with untreated or DMSO-treated controls. There was, however, no measurable increase in F-actin as determined by NBD-phallacidin blinding; (2)the values for the ratio (α-actinin/actin) are lower in PMNs treated with colchicine for 30 min, as compared with PMNs stimulated with fNLPNTL for 1 minute (non-polar ruffling cells) or 30 min (polarized locomoting cells); thus, this ratio may depend on the type of PMN motility; (3) in polarized PMNs F-actin was mainly located linearly all along the cell membrane; there was more intense staining at the front of the cells; (4) α-actining appeared to colocalize with F-actin at the leading front, but not with F-actin at the tail of polarized cells; (5) myosin was preferentially found at the rear part of polarized cells but not or only to a small extent at the front. Our data indicate a close functional correlation between microtubules and microfilaments. We speculate that F-actin in combination with α-actinin promotes expansion of pseudopods, whereas myosin combined with F-actin promotes contraction. In more general terms we suggest that different forms of PMN motility are generated by differential selective interaction of cytoskeletal compnents and variations in the composition of the cytoskeleton in different sites of the same cells. © 1993 Wiley-Liss, Inc.
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    Actin in the merozoite of the malaria parasite, Plasmodium falciparum (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 43-48 
    Details
    ISSN: 0886-1544
    Keywords: malaria ; Plasmodium falciparum ; merozoite ; actin ; ubiquitin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Merozoites of the human malaria parasite, Plasmodium falciparum, when treated with cytochalasin B, will attach irreversibly to red cells with formation of a vestigial internal (parasitophorous) vacuole, but they are inhibited from moving into the cell. The existence of an actin-based motile mechanism is implied. Immunoblotting, peptide mapping and the DNase inhibition assay have been used to show that the merozoite contains actin. It makes up an estimated 0.3% of the total parasite protein and is partitioned in the ratio of about 1:2 between the cytosolic and particulate protein fractions. In the former it is unpolymerised and in the latter filamentous. Most of the anti-actin-reactive protein in the soluble fraction and about 20% of that in the pellet has an apparent molecular weight of 55,000 and reacts with an anti-ubiquitin antibody; it is thus evidently ubiquitinyl actin, or arthrin, which has so far been detected only in insect flight muscle. © 1993 Wiley-Liss, Inc.
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    FRAP analysis of the stability of the microtubule population along the neurites of chick sensory neurons (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 59-72 
    Details
    ISSN: 0886-1544
    Keywords: microtubule dynamics ; photobleaching ; neurite elongation ; microtubule stability ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In order to study microtubule turnover in elongating neurites, chick embryo sensory neurons were microinjected with x-rhodamine tubulin, and after 6-12 hours, short segments along chosen neurites were photobleached at multiple sites. Previous studies [Lim et al., 1989; 1990] indicated that recovery of fluorescence (FRAP) in neurites occurs by the dynamic turnover of stationary microtubules. In all cases, distal bleached zones recovered fluorescence faster than bleached zones more proximally located along the same neurites. Bleached zones at growth cones completely recovered in 30-40 minutes, while bleached zones located more proximally usually recovered in 50-120 minutes. In the most proximal regions of long neurites, recovery of fluorescence was often incomplete, indicating that a significant fraction of the microtubules in these regions were very stable. These studies indicate that there are differences in microtubule stability along the lenght of growing neurites. These differences may arise from the combined effects of (1) modifications that stabilize and lengthen microtubules in maturing neurites and (2) the dynamic instability of the distally oriented microtubule plus ends. © 1993 Wiley-Liss, Inc.
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    Cellular automaton model of the actin cytoskeleton (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 87-104 
    Details
    ISSN: 0886-1544
    Keywords: polymerization ; solation ; gelation ; α-actinin ; gelsolin ; calcium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe a cellular automaton model of the actin cytoskeleton. The model incorporates spatial and temporal behavior at the macomolecular level and is relevant to the viscous nonequilibrium conditions suspected to occur in vivo. The model include cation and nucleotide binding to actin monomers, actin nucleation and polymerization into filaments, coss-linking with α-actinin, monomer sequestration with pfilin, filament severing, capping and nucleation with gelsolin, binding of profilin and gelsolin to membrane-bound phosphatidylinositide biphosphate (PIP2), and regulation of coss-linking and severing by changing calcium levels. We derive (1) equations for the molecular trnslation and rotation probabilities required for the cellular automaton simulation in terms of molecular size, shape, cytoplasmic viscosity, and temperature; and (2) equations for the binding probabilities of adjacent molecules in terms of experimentally determined reaction rate constants. The model accurately captures the known characteristics of actin polymerization and subsequent ATP hydrolysis under different cation and nucleotide conditions. An examination of gelation and sol-gel transitions resulting from calcium regulation of α-actinin and gelsolin predicts an inhomogeneous distribution of bound α-actinin and F-actin. The double-bound α-actinin (both ends bound to F-actin) is tightly bunched, while single-bound α-actinin is moderately bunched and unbound α-actinin is homogeneously distributed. The spatial organization of the α-actinin is quantified using estimates of fractal dimension. The simulation results also suggest that actin/α-actinin gels may shift from an isotropic to an amorphous phase after shortening of filaments. The gel-sol transition of the model shows excellent agreement with the present theory of polymer gels. The close correspondence of the model's predictions with previous experimental and theoretical results suggests that the model may be pertinent to better understanding the spatial and temporal properties of complex cytoskeletal processes. © 1993 Wiley-Liss, Inc.
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993) 
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    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250201
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    Video microscopy of organelle inheritance and motility in budding yeast (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 129-142 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; mitochondria ; vacuole ; kinesin ; myosin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: By adapting the time-lapse video microscopy techniques that were developed for larger, more complex cells, to living Saccharomyces cerevisiae cells, intracellular organelle movements were observed. Differential interference contrast optics revealed an organelle transport process in cells treated with mating pheromone. Small particles were observed to travel distances of up to 6 μm at rates of 0.11-0.17 (and in one case 0.80) μm/sec. Overall, the frequency of these motile events was quite low compared to what is observed in cell types traditionally studied by video microscopy. The ability to discern clearly the vacuole and nucleus in budding yeast revealed the dynamics of these organelles and the fact that their movements are carefully orchestrated during the cell cycle. Two types of vacuolar dynamics were observed: (1) interconversion between one large organelle and numerous smaller organelles and (2) the formation of projections that extend from the mother cell's vacuole into the bub. When applied to the study of the many available cytoskeletal and cell cycle mutants, the application of video microscopy to the study of organelle movements in living yeast cells will provide a unique opportunity to determine the molecular mechanisms of intracellular motility and to elucidate the temporal controls over these processes. © 1993 Wiley-Liss, Inc.
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    The kernel algorithm for PLS (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 45-59 
    Details
    ISSN: 0886-9383
    Keywords: Partial least squares ; PLS algorithm ; Kernel ; Multivariate image analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A fast and memory-saving PLS regression algorithm for matrices with large numbers of objects is presented. It is called the kernel algorithm for PLS. Long (meaning having many objects, N) matrices X (N × K) and Y (N × M) are condensed into a small (K × K) square ‘kernel’ matrix XTYYTX of size equal to the number of X-variables. Using this kernel matrix XTYYTX together with the small covariance matrices XTX (K × K), XTY (K × M) and YTY (M × M), it is possible to estimate all necessary parameters for a complete PLS regression solution with some statistical diagnostics. The new developments are presented in equation form. A comparison of consumed floating point operations is given for the kernel and the classical PLS algorithm. As appendices, a condensed matrix algebra version of the kernel algorithm is given together with the MATLAB code.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070104
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  • 194
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    Eliminating complex eigenvectors and eigenvalues in multiway analyses using the direct trilinear decomposition method (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 77-88 
    Details
    ISSN: 0886-9383
    Keywords: Direct trilinear decomposition method ; Curve resolution ; Trilinear data ; Similarity transformation ; Generalized rank annihilation method ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The direct trilinear decomposition method (DTDM) is an algorithm for performing quantitative curve resolution of three-dimensional data that follow the so-called trilinear model, e.g. chromatography-spectroscopy or emission-excitation fluorescence. Under certain coditions complex eigenvalues and eigenvectors emerge when the generalized eigenproblem is solved in DTDM. Previous publications never treated those cases. In this paper we show how similarity transformations can be used to eliminate the imaginary part of the complex eigenvalues and eigenvectors, thereby increasing the usefulness of DTDM in practical applications. The similarity transformation technique was first used by our laboratory to solve the similar problem in the generalized rank annihilation method (GRAM). Because unique elution profiles and spectra can be derived by using data matrices from three or more samples simultaneously, DTDM with similarity transformations is more efficient than GRAM in the case where there are many samples to be investigated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070202
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  • 195
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    The Laboratory for Analytical Chemistry, University of Nijmegen, Nijmegen, The Netherlands (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 143-148 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070207
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  • 196
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    Editorial (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 151-151 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070302
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  • 197
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    The chemometrics activities at Eastman Kodak, Rochester, New York (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 213-222 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070307
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  • 198
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    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993) 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070401
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  • 199
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    Determination of a multivariate detection limit and local chemical rank by designing a non-parametric test from the zero-component regions (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 277-289 
    Details
    ISSN: 0886-9383
    Keywords: Multicomponent analysis ; Factor analysis ; Detection limit ; Local rank ; Zero-component region ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In this paper we redefine the term detection limit to embrace the inherent multivariate nature of samples, instrumental measurements and chemometrics resolution procedures. The so-called zero-component regions, i.e. parts with no chemical components eluting, are used as repeated analytical blanks to estimate a statistical multivariate detection limit for determining the number of chemical species in local regions of a single two-way chromatogram or a collection of synchronized one-way chromatograms. For two-way chromatography the detection limit is determined from the distribution of the first eigenvalues obtained from all possible combinations of spectra in the zero-component regions. The number of spectra in each calculation should correspond to the number included in the later examination of the local retention time regions. For one-way chromatography on a collection of samples with similar chemical components at varying concentrations the same procedure is used, with the samples taking the role of the spectra in two-way chromatography. The detection limit can be chosen at various confidence levels depending on whether false positive or negative detection of minor components is most critical. The results obtained from the zero-eigenvalue distribution are more robust than those obtained by a previously developed F-test.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070406
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  • 200
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    Istituto di analisi E Tecnologie farmaceutiche ed alimentari, University of Genoa, Italy (1993)
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 7 (1993), S. 447-452 
    Details
    ISSN: 0886-9383
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cem.1180070509
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