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  • Ultrastructure  (52)
  • Coleoptera  (44)
  • Springer  (96)
  • American Association of Petroleum Geologists (AAPG)
  • Nature Publishing Group
  • 1995-1999  (28)
  • 1980-1984  (68)
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  • Springer  (96)
  • American Association of Petroleum Geologists (AAPG)
  • Nature Publishing Group
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructure of the sperms ofPlumbago zeylanica (1981)
    Springer
    Protoplasma 107 (1981), S. 85-107 
    Details
    ISSN: 1615-6102
    Keywords: Male cytoplasmic inheritance ; Plumbago ; Pollen grain ; Pollen tube ; Sperm ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Male gametes ofPlumbago zeylanica were examined in pollen grains and tubes using light and electron microscopy of chemically and physically fixed tissues, and Nomarski interference microscopy of isolated, living sperm cells. Male gametes are elongate, spindleshaped cells containing a nucleus, mitochondria, ER, ribosomes, vesicles, dictyosomes, probable microfilaments, and a variable number of plastids. In mature pollen grains ofP. zeylanica, the two sperm cells are directly linked; they share a transverse cell wall with plasmodesmata and are enclosed together by the inner vegetative cell plasma membrane. One of these two sperms is also associated with the vegetative nucleus as a consistent feature of pollen grain organization. The basis of this association appears to be a long, narrow projection of the sperm cell (averaging 〈 1 μm wide and about 30 μm long) which wraps around the periphery of the vegetative nucleus and occupies embayments of that nucleus. This association is maintained throughout pollen tube growth but becomes less extensive near the completion of tube growth and is severed following tube discharge. The consistent occurrence of the sperm-vegetative nucleus association in pollen grains, tubes and isolated pollen cytoplasm suggests that the two structures may be directly connected, but attempts to visualize this type of connection were unsuccessful. Possibly, the entwining nature and extent of complementary interfaces between vegetative nucleus and sperm may have a role in stabilizing their association. Functionally, the two sperms and vegetative nucleus appear to travel as a linked unit within the pollen tube, possibly increasing the effectiveness of gamete delivery and helping to ensure nearly simultaneous transmission of sperms into the receptive megagametophyte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01275610
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  • 2
    Electronic Resource
    Electronic Resource
    Physiology and costs of resistance to herbivory and disease in Brassica (1996)
    Springer
    Entomologia experimentalis et applicata 80 (1996), S. 231-237 
    Details
    ISSN: 1570-7458
    Keywords: Leptosphaeria maculans ; Peronospora parasitica ; fungal pathogens ; Phyllotreta cruciferae ; flea beetles ; Coleoptera ; Chrysomelidae ; Cruciferae ; chitinase ; myrosinase ; allocation costs ; plant defense mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We used artificial selection experiments to study genetic allocation costs and physiological mechanisms of resistance to herbivory and fungal disease. Genetic costs to resistance were present in some instances and absent in others. Genetic resistance to the fungal pathogen, Leptosphaeria maculans was cost-free, while resistance to Peronospora parasitica showed a negative genetic correlation between disease resistance and growth rate. Leptosphaeria resistant genotypes had 13% higher chitinase activity. Genetic increases in myrosinase activity were correlated with increased resistance to flea beetles (Phyllotreta cruciferae), but resulted in lower plant fecundity, presumably due to production costs of myrosinase. Genetic costs of resistance may maintain genetic variation in natural plant populations. These studies demonstrate the predictive and explanatory power of a functional approach to plant-herbivore and plant-pathogen interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194764
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  • 3
    Electronic Resource
    Electronic Resource
    Ecdysteroids during pupal development of female Xyleborus ferrugineus (1981)
    Springer
    Entomologia experimentalis et applicata 30 (1981), S. 151-156 
    Details
    ISSN: 1570-7458
    Keywords: Xyleborus ferrugineus ; pupae ; ecdysteroids ; pharate adult ; radioimmunoassay ; Coleoptera ; Scolytidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Der Ecdysteroidtiter weiblicher Puppen von Xyleborus ferrugineus (Fabr.) wurde geschätzt, indem ganze Tiere homogenisiert und radioimmunologisch untersucht wurden. Ein ausgeprägtes Maximum an Ecdysteroiden wurde bei 36 Stunden Puppenent-wicklung beobachtet (743 pg/mg Körpergewicht). Der Titer nahm ab auf 299 pg/mg im Pharatstadium und auf 193 pg/mg unmittelbar vor Schlüpfen der Adulten. Qualitative Studien mit HPLC ergaben in frischen Puppen ein Verhältnis von 3:1 Ecdyson zu 20-Hydrooxyecdyson. Pharatstadien enthielten vor allem 20-Hydrooxyecdyson. Das beobachtete einzige Maximum im Titer stimmt überein mit den Resultaten bei andern untersuchten Coleopteren.
    Notes: Abstract Ecdysteroid titers were estimated on the whole body homogenates of Xyleborus ferrugineus (Fabr.) female pupae during development by radioimmunoassay. A distinct peak of ecdysteroids was observed at 36-hr pupal development (743 pg/mg body wt). Titer declined to 299 pg/mg by the pharate adult stage and to 193 pg/mg body wt just before adult emergence. Qualitative studies by HPLC revealed a ratio of 3:1 ecdysone to 20-hydroxyecdysone in the initial pupal stage. Pharate adults had mainly 20-hydroxyecdysone. The observed single peak in ecdysteroid titer agrees with findings in other studied coleopteran species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300880
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  • 4
    Electronic Resource
    Electronic Resource
    Ultrastructure of the cyanobacterium,Mastigocladus laminosus (1982)
    Springer
    Archives of microbiology 133 (1982), S. 11-19 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Mastigocladus laminosus ; Fischerella ; True branching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology and ultrastructure of the thermophilic cyanobacteriumMastigocladus laminosus were examined by scanning and transmission electron microscopy. Mature cultures consisted of relatively old, wide filaments that branched frequently to form younger, thinner filaments. The cells of the younger filaments had a consistently cylindrical morphology, while those of older filaments were rounded and pleomorphic. The internal ultrastructure of the cells depended somewhat on their age. As young cells became larger and wider, their thylakoids underwent slight rearrangement and spread out toward the center of the cytoplasm. Polyphosphate bodies, carboxysomes (polyhedral bodies), and lipid-body-like structures increased in number as the cells aged, but ribosomes and cyanophycin granules were depleted. Cell division involved septum formation followed by ingrowth of the outer membrane and sheath. Cells in older filaments were separated from each other by a complete layer of sheath material. Septum formation in older cells was also seen to occur parallel to the long axis of the filament, thereby confirming that true branching took place.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00943762
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  • 5
    Electronic Resource
    Electronic Resource
    The effects of nitrogen limitation on the ultrastructure of the cyanobacterium Agmenellum quadruplicatum (1981)
    Springer
    Archives of microbiology 130 (1981), S. 204-212 
    Details
    ISSN: 1432-072X
    Keywords: Agmenellum quadruplicatum ; Nitrogen starvation ; Ultrastructure ; PATO poststain ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of nitrogen limitation on the ultrastructure of the unicellular cyanobacterium, Agmenellum quadruplicatum, were studied by thin sectioning transmission electron microscopy. Nitrogen became limiting for growth 14–15 h after transfer to nitrogen-limiting medium, but cultures retained full viability for at least 45 h. The c-phycocyanin: chlorophyll a ratio and cellular nitrogen content of the culture dropped rapidly after 14–15 h, as a progressive deterioration of major cell structures took place. Phycobilisomes were degraded first, followed by ribosomes and, then, thylakoid membranes. These structures were virtually depleted from the cells within 26 h. Intracellular polysaccharide accumulated in place of the normal cell structures throughout this period. Nitrogen limitation did not affect polyphosphate bodies, carboxysomes, lipid granules, the cell envelope, or the extra-cellular glycocalyx. All of the ultrastructural changes resulting from nitrogen limitation were reversed upon addition of nitrate to a starved culture. Most cell structures were restored within 3 h, and restoration was complete within 9 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00459520
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  • 6
    Electronic Resource
    Electronic Resource
    Geographic Variation in Response of Pine Engraver, Ips pini, and Associated Species to Pheromone, Lanierone (1997)
    Springer
    Journal of chemical ecology 23 (1997), S. 2013-2031 
    Details
    ISSN: 1573-1561
    Keywords: Ips pini ; Ips integer ; Coleoptera ; Scolytidae ; aggregation pheromone ; lanierone ; ipsdienol ; geographic variation ; synergism ; Enoclerus lecontei ; Cleridae ; kairomone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Lanierone strongly synergized the attraction of male and female Ips pini (Say) to ipsdienol in New York and Wisconsin. Synergy was only weakly significant in Montana and British Columbia and not significant in California. Catches of I. pini in ipsdienol-baited traps were increased 0% ( i.e., nonsignificant) to 9942% by lanierone, with the highest increases in eastern North America. Lanierone had the least effect in California. The effects of lanierone on sex ratios of I. pini in trap catches varied significantly between regions. The addition of lanierone to ipsdienol-baited traps resulted in a general increase in male representation at nine of 12 sites. Ips integer (Eichhoff) was attracted to lanierone alone. Ipsdienol reduced the response of I. integer to lanierone. Enoclerus lecontei (Wolcott) (Cleridae) preferred traps baited with the combination of ipsdienol and lanierone. (R)-(–)-Ipsdienol was attractive to E. sphegeus (F.), Thanasimus undatulus (Say) (Cleridae), and Temnochila chlorodia (Mannerheim) (Trogositidae), while racemic ipsdienol was attractive to E. nigrifrons var. gerhardi Wolc. and Thanasimus dubius (F.). Lanierone had no effect on these species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/B:JOEC.0000006486.39056.48
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  • 7
    Electronic Resource
    Electronic Resource
    Defensive adaptations of eggs and adults ofGastrophysa cyanea (Coleoptera: Chrysomelidae) (1982)
    Springer
    Journal of chemical ecology 8 (1982), S. 453-462 
    Details
    ISSN: 1573-1561
    Keywords: Defensive secretions ; oleic acid ; hydrocarbons ; terpenoids ; eggs ; deterrents ; ants ; predation ; Chrysomelidae ; Coleoptera ; Gastrophysa cyanea ; reflex bleeding ; elytral glands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Egg clusters and adults ofGastrophysa cyanea are conspicuous and, like their larvae, are chemically protected. The eggs owe their bright yellow color primarily to β-carotene and, in addition, contain substantial quantities of oleic acid. At natural concentrations oleic acid effectively deters many species of ants from feeding. The use of fatty acids as deterrents against ants is discussed as a possible widespread phenomenon among insects. During defensive confrontations, adults ofG. cyanea exhibit avoidance behavior and may also feign death. In addition, the adults may autohemmorhage or secrete a fluid from elytral or pronotal pores in response to traumatic stimuli. The secretions are effective against ants and contain a mixture of hydrocarbons as well as terpenoid components. The pattern of ontogenetic modification in the defensive chemical repertoire ofG. cyanea is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00987793
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructure of the prothoracic gland of variously aged female pupae of Xyleborus ferrugineus and associated ecdysteroid titers (1980)
    Springer
    Cell & tissue research 213 (1980), S. 1-8 
    Details
    ISSN: 1432-0878
    Keywords: Ecdysteroids ; Moulting hormones ; Xyleborus ferrugineus pupae ; Ultrastructure ; Prothoracic gland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The prothoracic glands of female pupae of Xyleborus ferrugineus at three ages (0-h, 48-h and 72-h-old) were examined for ultrastructural changes that correlate with high titers of ecdysteroids in the entire pupa. In all three ages, the prothoracic gland cells appear compact with a prominent nucleus. Lysosome-like structures with concentrically oriented internal membrane are observed in both 0-h and 72-h-old gland cells. Mitochondria are abundant in the glands of both ages, and rough endoplasmic reticulum is relatively sparse. Numerous microtubules are present in the prothoracic gland cells of 48-h-old female pupae that contain relatively high titers of ecdysteroids. Rough endoplasmic reticulum also is especially abundant at this age of the pupa. Ecdysone titers, estimated by the radioimmunoassay method (RIA), were 161.04±22.61 pg/mg, 704.25±69.02 pg/mg and 298.72±26.80pg/mg body weight in 0-h, 48-h and 72-h-old female pupae, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236915
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  • 9
    Electronic Resource
    Electronic Resource
    Stomatal pore and cuticle formation inFunaria (1983)
    Springer
    Protoplasma 116 (1983), S. 1-13 
    Details
    ISSN: 1615-6102
    Keywords: Cuticle ; Peristomatal transpiration ; Stomata ; Ultrastructure ; Funaria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cuticle and pore development in the guard cells ofFunaria were investigated with the electron microscope. Pore cuticle formation is simultaneous with the creation of the pore itself. The morphology of the pore cuticle is unlike that of any cuticle described in the literature. It has many lamellae which are penetrated by electron dense fibrils. Three different cuticular morphologies exist from the pore to the subsidiary cell walls. The cuticles on the pore and outer walls contain fibrils that sometimes reach to the surface. The subsidiary cell cuticle lacks fibrils altogether. It is hypothesized that (1) cuticularization of the middle lamella contributes to ventral wall separation and (2) differences in extent of cuticular fibrils are related to greater water loss from stomata than from subsidiary cells (peristomatal transpiration).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01294225
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  • 10
    Electronic Resource
    Electronic Resource
    Topography, ultrastructure and phagocytic capacity of avian lymph nodes (1983)
    Springer
    Cell & tissue research 228 (1983), S. 389-403 
    Details
    ISSN: 1432-0878
    Keywords: Lymph node, avian ; Ultrastructure ; Macrophages ; Phagocytic capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the avian lymph node (ALN) is characterized by a thin capsule, thin lymphoreticular cords, and an absence of trabeculae. It is not possible to subdivide the ALN into cortex, paracortex and medulla, or to subdivide the system of sinuses into marginal, trabecular and medullary divisions. The lymphoreticular cords contain avian germinal centers (AGC) with B-lymphocytes and the area of T-lymphocytes. Postcapillary venules are responsible for the recirculation of lymphocytes. Sinus reticular cells do not exist in the ALN, but free macrophages are present. The phagocytic capacity of the macrophages was determined by injection of vital dyes (India ink, Berlin blue) and inoculation with Candida cells. Macrophages filled with markers migrate from the lymph sinuses into the lymphoreticular cords and further into the AGC. The mobility of the macrophages is remarkably lower after phagocytosis of Candida cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00204887
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