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  • Articles  (87)
  • Turbellaria  (35)
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  • Articles  (87)
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  • Springer  (87)
  • Annual Reviews
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  • Oxford University Press
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  • 2020-2022
  • 1980-1984  (87)
  • 1970-1974
  • 1950-1954
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  • 1
    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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  • 2
    Electronic Resource
    Electronic Resource
    Electron microscopical investigations of the intercellular contacts during the early cleavage stages ofLymnaea stagnalis (Mollusca, Gastropoda) (1981)
    Springer
    Development genes and evolution 190 (1981), S. 215-220 
    Details
    ISSN: 1432-041X
    Keywords: Mollusca ; Cleavage ; Junctions ; Interaction ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In early cleavage stages ofLymnaea stagnalis, three kinds of intercellular junctions could be distinguished up to the sixth cleavage: intermediate, septate and gap junctions. The first two form “junctional belts” located on the cell border at the periphery of the embryo. For the purpose of our study we were most interested in gap junctions as they are alleged to be structures that allow cell-to-cell communication. Gap junctions first appear at the four cell stage. Up to the sixth cleavage no difference in the distribution pattern could be found between and within each of the four quadrants of the embryo. Some of the cell tiers along the animal-vegetal axis lack gap junctions either between the blastomeres within the tier or between the blastomeres from adjacent tiers. All gap junctions observed in freeze fracture replicas show plaques with an irregular IMP pattern. The average IMP diameter measures 12 nm (SD±2 nm). In stages fixed after the fifth cleavage, gap junctions are found between micromeres at the animal pole and the central 3D macromere. This is in agreement with the presumed interaction between these cells at this stage. The possibility of a transition of non-functional into functional gap junctions after the fifth cleavage is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848305
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  • 3
    Electronic Resource
    Electronic Resource
    Major haemolymph proteins inCeratitis capitata: Biosynthesis and secretion during development (1981)
    Springer
    Development genes and evolution 190 (1981), S. 33-39 
    Details
    ISSN: 1432-041X
    Keywords: Ceratitis capitata ; Major haemolymph proteins ; Development ; Fat body ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The accumulation of major haemolymph proteins (a group of proteins immunologically related to Calliphorin) their biosynthesis in vivo and in organ culture as well as their secretion, has been studied during the late larval stages and white pupae of the Mediterranean fruit flyCeratitis capitata. The accumulation of major haemolymph proteins in the haemolymph, shows a twenty fold increase from the 4-day old larvae to the white pupae stage, while in the fat body there is only a seven fold increase. It is evident from the in vivo and organ culture studies, that the major haemolymph proteins are synthesized during the late larval stage and their synthesis declines abruptly during the stage of white pupae. It seems also that each polypeptide has its own characteristic developmental kinetics of synthesis. The major haemolymph proteins are synthesized in the fat body and are very quickly secreted into the haemolymph.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00868701
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  • 4
    Electronic Resource
    Electronic Resource
    Photosynthesis under osmotic stress (1981)
    Springer
    Planta 153 (1981), S. 430-435 
    Details
    ISSN: 1432-2048
    Keywords: Chloroplast ; Photosynthesis (stress recovery) ; Protoplast ; Spinacia ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The reversibility of the inhibition of photosynthetic reactions by water stress was examined with four systems of increasing complexity—stromal enzymes, intact chloroplasts, mesophyll protoplasts, and leaf slices. The inhibition of soluble chloroplast enzymes by high solute concentrations was instantly relieved when solutes were properly diluted. In contrast, photosynthesis was not restored but actually more inhibited when isolated chloroplasts exposed to hypertonic stress were transferred to conditions optimal for photosynthesis of unstressed chloroplasts. Upon transfer, chloroplast volumes increased beyond the volumes of unstressed chloroplasts, and partial envelope rupture occurred. In protoplasts and leaf slices, considerable and rapid, but incomplete restoration of photosynthesis was observed during transfer from hypertonic to isotonic conditions. Chloroplast envelopes did not rupture in situ during water uptake. It is concluded that inhibition of photosynthesis by severe water stress is at the biochemical level brought about in part by reversible inhibition of chloroplast enzymes and in part by membrane damage which requires repair mechanisms for reversibility. Both soluble enzymes and membranes appear to be affected by the increased concentration of internal solutes, which is caused by dehydration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00394981
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  • 5
    Electronic Resource
    Electronic Resource
    Secondary fluorescence kinetics of spinach leaves in relation to the onset of photosynthetic carbon assimilation (1981)
    Springer
    Planta 153 (1981), S. 273-278 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll fluorescence ; CO2 assimilation, photosynthetic ; Photosynthesis (induction) ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract When spinach leaves are re-illuminated, after dark periods of 90 s or less, an initial fluorescence peak is observed which rapidly gives way to a much lower terminal value. After 2 min or more in the dark, however, there is a secondary rise, at about 50–70 s, which then gives way, more slowly, to approximately the same low terminal value as before. The secondary rise is eliminated or disguised by feeding D,L-glyceraldehyde (a specific inhibitor of photosynthetic carbon assimilation) and by manose, 2-deoxyglucose and glucosamine, all of which are believed to sequester cytoplasmic orthophosphate. This secondary rise in fluorescence is discussed in relation to photosynthetic induction and the manner in which these compounds may modulate fluorescence by their effect on the availability of orthophosphate and their consequent impact on the adenylate status of the stroma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00383899
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  • 6
    Electronic Resource
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    On the compartmentation of isopentenyl diphosphate synthesis and utilization in plant cells (1981)
    Springer
    Planta 153 (1981), S. 578 
    Details
    ISSN: 1432-2048
    Keywords: Chloroplasts ; Chromoplasts ; Isopentenyl diphosphate ; Narcissus ; Polyprenoids ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Purified spinach chloroplast and daffodil chromoplast preparations do not use mevalonate, phosphomevalonate, and diphosphomevalonate for the synthesis of isopentenyl diphosphate. Isopentenyl diphosphate, on the other hand, is incorporated into plastidal polyprenoids in large amounts. In the presence of a cytoplasmic supernatant, however, mevalonate and the phosphomevalonates were incorporated into the plastidal polyprenoids in equally large amounts, which demonstrates that the enzymes mevalonate kinase (EC 2.7.1.36), phosphomevalonate kinase (EC 2.7.4.2), and diphosphomevalonate decarboxylase (EC 4.1.1.33) are soluble cytoplasmic enzymes and that they apparently do not occur as isoenzymes within the plastids. The concept is developed that isopentenyl diphosphate is a central intermediate in plant polyprenoid formation which is channeled into several compartment for different biosynthetic pathways.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385544
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis of acyl-CoAs by isolated spinach chloroplasts in relation to added CoA and ATP (1981)
    Springer
    Planta 153 (1981), S. 519-523 
    Details
    ISSN: 1432-2048
    Keywords: Acyl-CoA synthesis ; Chloroplast (isolated) ; Lipid synthesis ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The kinetics of incorporation of [2-14C] acetate into lipids and acyl-CoAs in relation to added CoA and ATP by isolated spinach chloroplasts have been examined. The effect of the concentration of these cofactors on lipid and acyl-CoA synthesis was also studied. In the absence of cofactors, or when only one was present, the incorporation was very low and went mainly into lipids. When both cofactors were present a strong stimulation of both activities occurred. After 25 min, acyl-CoAs were more strongly labeled than lipids and both activities continued linearly for at least 60 min.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385535
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  • 8
    Electronic Resource
    Electronic Resource
    Metabolism of hydroxylamine by spinach leaf discs and its relationship to nitrate reduction (1981)
    Springer
    Planta 151 (1981), S. 151-156 
    Details
    ISSN: 1432-2048
    Keywords: Hydroxylamine ; Nitrate reductase ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrate reduction in vivo by spinach leaf discs was shown to be inhibited by hydroxylamine when this was included in the nitrate reductase assay solutions or introduced to the tissue during a preincubation period. The sensitivity of nitrate reduction to hydroxylamine was not sufficient to suggest a natural process, considering the small endogenous concentrations of hydroxylamine in the leaves. Inhibition of nitrate reduction in vivo could be approximately related to rates of in vitro inhibition of nitrate reductase by this compound. There was no need to suppose conversion of hydroxylamine to cyanide to inhibit nitrate reduction. Some of the in vivo and in vitro characteristics of hydroxylamine inhibition of nitrate reductase are described. Hydroxylamine was metabolised by discs at rates comparable to nitrate reduction. Rates of metabolism of hydroxylamine, and its accumulation in the tissues from an external solution were both enhanced by light but little affected by anaerobiosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387817
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  • 9
    Electronic Resource
    Electronic Resource
    Light activation of fructose bisphosphatase in isolated spinach chloroplasts and deactivation by hydrogen peroxide (1981)
    Springer
    Planta 151 (1981), S. 242-246 
    Details
    ISSN: 1432-2048
    Keywords: Calvin cycle ; Chloroplast ; Fructose bisphosphatase ; Hydrogen peroxide ; Light (thioredoxin formation) ; Spinacia ; Thioredoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Spinach chloroplast fructose bisphosphatase (EC 3.1.3.11.) exists in both oxidised and reduced forms. Only the latter has the kinetic properties that allow it to function at physiological concentrations of fructose 1,6-bisphosphate and Mg2+. Illumination of freshly prepared type A chloroplasts causes a conversion of oxidised to reduced enzyme. The rate of this conversion does not limit the rate of CO2 fixation. In the dark the reduced enzyme partially reverts back to the oxidised form. If catalase is omitted from the reaction medium the rate of CO2 fixation by chloroplasts is decreased and seems to be limited by the rate of conversion of the enzyme to the reduced form. The physiological significance of the light dependent generation of dithiol compounds (such as thioredoxin) within chloroplasts is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395175
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  • 10
    Electronic Resource
    Electronic Resource
    Reversible heat-inactivation of the calvin cycle: A possible mechanism of the temperature regulation of photosynthesis (1981)
    Springer
    Planta 151 (1981), S. 33-39 
    Details
    ISSN: 1432-2048
    Keywords: Calvin cycle ; Electrochromic shift ; Light scattering ; Ribulose-1,5-bisphosphate carboxylase ; Spinacia ; Temperature regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Photosynthetic CO2 fixation rates in leaves and intact chloroplasts of spinach measured at 18°–20° C are substantially decreased by pretreatment at temperatures exceeding 20° C. Mild heating which causes 80% inhibition of CO2 fixation does not affect phosphoglyceroacid reduction and causes increases in the ATP/ADP ratio and the light-induced transthylakoid proton gradient. The inactivation of the CO2 fixation is completely reversible with half-times of recovery in the order of 15–20 min. Comparison of steady-state patterns of 14C labeled Calvin cycle intermediates of heat-treated and control samples reveals a large increase in the ribulose-1,5-bisphosphate/phosphoglyceroacid ratio and a large decrease in the phosphoglyceroacid/triosephosphate ratio. It is concluded that inactivation of CO2 fixation occurring at elevated temperatures is caused by inhibition of the ribulose-1,5-bisphosphate carboxylase (EC 4.1.1.39). Measurements of light-induced light scattering changes of thylakoids and of the light-induced electrochromic absorption shift show that these signals are affected by mild heating in a way which is strictly correlated with the inactivation of the CO2 fixation. It is proposed that the function of the ribulose-1,5-bisphosphate carboxylase in vivo requires a form of activation that involves properties of the thylakoid membrane which are affected by the heat treatment. The fact that these changes in thylakoid membrane properties and of ribulose-1,5-bisphosphate carboxylase activity are already affected at elevated temperatures which can still be considered physiological, and the reversible nature of these changes, suggest that they may play a role in temperature regulation of the overall photosynthetic process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00384234
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  • 11
    Electronic Resource
    Electronic Resource
    Foliar flavonoid distribution during Spinacia chloroplast isolation (1981)
    Springer
    Planta 151 (1981), S. 309-313 
    Details
    ISSN: 1432-2048
    Keywords: Chloroplasts ; Flavonoids ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The flavonoid glycoside accumulation level was compared in class A and in class C spinach chloroplast suspensions. Class A chloroplasts (up to 97% intact) contained about 0.4% of the total flavonoid glycosides present in leaves. Further purification of 97%-intact chloroplast suspensions, through a Percoll gradient, reduced the glycoside level to less than 0.15%. On the other hand, class C chloroplasts (100% broken plastids) contained between 10 to 30 times more flavonoids than intact Percoll purified chloroplasts. These results indicate that chloroplasts could bind vacuolar glycosides during their period of isolation. This hypothesis was confirmed by controlled contamination experiments using a cell-free supernatant as a source of vacuolar glycosides. Furthermore, the level of flavonoids in chloroplasts could be decreased to a level close to that obtained in intact Percoll purified chloroplasts by washing with soluble polyvinylpyrolidone. The results presented in this paper demonstrate the importance of maintaining the physiological integrity of plastids during the course of organelle isolation when investigating flavonic compartmentation in leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393283
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  • 12
    Electronic Resource
    Electronic Resource
    Freezing injury in cold-acclimated and unhardened spinach leaves (1981)
    Springer
    Planta 151 (1981), S. 339-346 
    Details
    ISSN: 1432-2048
    Keywords: Chloroplast and freezing ; Freezing injury ; Frost tolerance ; Photosynthesis and freezing ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Spinach plants (Spinacia oleracea L.) were frost-hardened by cold-acclimation to 1° C or kept in an unhardy state at 20°/14° C in phytotrons. Detached leaves were exposed to temperatures below 0°C. Rates of photosynthetic CO2 uptake by the leaves, recorded after frost treatment, served as a measure of freezing injury. Thylakoid membranes were isolated from frost-injured leaves and their photosynthetic activities tested. Ice formation occurred at about-4° to-5° C, both in unhardened and cold-acclimated leaves. After thawing, unhardened leaves appeared severely damaged when they had been exposed to-5° to-8° C. Acclimated leaves were damaged by freezing at temperatures between-10° to-14° C. The pattern of freezing damage was complex and appeared to be identical in hardened and unhardened leaves: 1. Inactivation of photosynthesis and respiration of the leaves occurred almost simultaneously. 2. When the leaves were partly damaged, the rates of photosynthetic electron transport and noncyclic photophosphorylation and the extent of light-induced H+ uptake by the isolated thylakoids were lowered at about the same degree. The dark decay of the proton gradient was, however, not stimulated, indicating that the permeability of the membrane to-ward protons and metal cations had not increased. 3. As shown by partial reactions of the electron transport system, freezing of leaves predominantly inhibited the oxygen evolution, but photosystem II and photosystem I-dependent electron transport were also impaired. 4. Damage of the chloroplast envelope was indicated by a decline in the percentage of intact chloroplasts found in preparations from injured leaves. The results are discussed in relation to earlier studies on freezing damage of thylakoid membranes occurring in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393288
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  • 13
    Electronic Resource
    Electronic Resource
    Freezing injury in cold-acclimated and unhardened spinach leaves (1981)
    Springer
    Planta 151 (1981), S. 347-352 
    Details
    ISSN: 1432-2048
    Keywords: Chlorophyll, fluorescence ; CO2 assimilation ; Freezing injury ; Light scattering (leaves) ; Membrane potential ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leaves from cold-acclimated and from unhardened spinach plants (Spinacia oleracea L.) were subjected to a freezing/thawing procedure in which varying minimum temperatures were reached. Subsequently, the chlorophyll fluorescence induction signal (Kautsky phenomenon) and the light-induced apparent absorbance changes at 535 nm (light-scattering changes indicative of the proton gradient, and absorbance changes induced by the membrane potential) of the leaves were studied to obtain information on the course and mechanism of frost damage to the photosynthetic apparatus. Membrane energization as indicated by these signals was related in a complex way to the inactivation of CO2 assimilation due to the progressing impact of freezing: In the absence of CO2, the maximum energization of the thylakoids was progressively decreased. According to altered fluorescence signals, the electron transport system was affected in parallel. In the presence of CO2, energization frequently appeared increased when the leaves had been partially damaged, i.e., when the CO2 assimilation rates were lowered. The results suggest that the primary frost injury in chloroplasts of intact leaves consists of an inhibition of the energy conserving photosynthetic processes and, in addition, of a partial inactivation of the carbon reduction cycle. The pattern of freezing injury was no different in frost-hardened and unhardened leaves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00393289
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  • 14
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    Photosynthesis of isolated chloroplasts and protoplasts under osmotic stress (1981)
    Springer
    Planta 151 (1981), S. 375-380 
    Details
    ISSN: 1432-2048
    Keywords: Chloroplast volume ; Photosynthesis and chloroplast volume ; Spinacia ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. Isolated intact spinach chloroplasts respond to changes of the sorbitol concentration of the suspending medium as near-perfect osmometers within a large range of osmotic potentials. Under isotonic conditions (π=9–10 bar), their average osmotic volume is 24 μm3 and the total volume 36 μm3. The osmotic volume can be increased to 63 μm3 by lowering the sorbitol concentration until a critical osmotic potential of π=4 bar is reached. Below that value chloroplasts rupture. Between 10 bar and 4 bar, volume changes are reversible. 2. Increasing the chloroplast volume above 24 μm3 causes inhibition of photosynthesis, with 50% inhibition occurring at an osmotic potential of π=5–6 bar. This corresponds to an osmotic volume of 45–55 μm3. Depending on the duration of hypotonic treatment, inhibition of photosynthesis is more or less reversible. 3. Between 4 and 10 bar, the chloroplast envelope exhibits a very low permeability for ferricyanide, many metabolites, and soluble stroma proteins. 4. Electron transport is not inhibited by swelling of chloroplasts. Also, the ATP/ADP-ratio remains unchanged. 5. The solute concentration in the chloroplasts appears to be optimal for photosynthesis at 10 bar. Increasing the chloroplast volume causes inhibition of photosynthesis by dilution effects.
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    URL: http://dx.doi.org/10.1007/BF00393294
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  • 15
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    Effects of freezing on isolated plant mitochondria (1981)
    Springer
    Planta 152 (1981), S. 242-247 
    Details
    ISSN: 1432-2048
    Keywords: Freezing injury ; Frost resistance ; Mitochondria ; Respiration ; Solanum ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mitochondria isolated from spinach leaves (Spinacia oleracea L.) and potato tubers (Solanum tuberosum L.) were partly injured when subjected to freezing for 2 to 4 h at-25°C in salt solutions in the absence of cryoprotectants. Damage was manifested by the inactivation of respiratory properties and increase in the permeability of the mitochondrial membranes. Decrease in respiratory control indicated that the control mechanism of the electron transport chain was influenced by freezing. Oxidative phosphorylation was only slightly more affected than electron transport. The inactivation of the membrane systems was caused by an increase in the concentration of membrane-toxic solutes. This was confirmed by treatment of the organelles at 0°C in solutions of high salt concentrations. When sugar was present in the course of freezing, mitochondria were partly or completely protected. On a molar basis, sucrose was more effective in membrane protection than glucose. Under certain conditions amino acids, e.g., proline and hydroxyproline, also stabilized isolated mitochondria during freezing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385151
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  • 16
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    An ultrastructural search for lectin-binding sites on surfaces of spinach leaf organelles (1981)
    Springer
    Planta 152 (1981), S. 145-152 
    Details
    ISSN: 1432-2048
    Keywords: Lectin binding ; Membranes (surfaces) ; Nicotiana ; Organelles (leaf) ; Protoplasts ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Organelles isolated from leaves of spinach (Spinacia oleracea L.) were prefixed in glutaraldehyde and then incubated with ferritin conjugates of four lectins — Concanavalin A (Con A), Ricinus communis L. agglutinin, MW 120,000 (RCA), soybean agglutinin (SBA), and wheat germ agglutinin (WGA) — in order to probe their cytoplasmic surfaces for saccharide residues. In each case the major leaf organelles, including microbodies, mitochondria and chloroplast derivatives, failed to exhibit labeling when examined with the electron microscope. Tobacco (Nicotiana tabacum L.) leaf protoplasts, incubated simultaneously with and under identical conditions to the spinach organelles, showed specific labeling of their plasma membranes with all four lectin conjugates, thus establishing the efficacy of the procedure for demonstrating the presence of binding sites when they exist. Further attempts to show binding of one of the lectins, Con A, by labeling with fluorescein-Con A and by organelle agglutination, yielded results consistent with the absence of ultrastructural labeling. It is concluded that no saccharide residues recognized by the four lectins are present on the cytoplasmic surfaces of organelles and that those residues reported to be constituents of intracellular membranes, therefore, are most likely exposed on the luminal (extracytoplasmic) surfaces.
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    URL: http://dx.doi.org/10.1007/BF00391186
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  • 17
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    Adenine nucleotides and energy charge evolution during the induction of flowering in spinach leaves (1981)
    Springer
    Planta 152 (1981), S. 189-194 
    Details
    ISSN: 1432-2048
    Keywords: Adenine nucleotide pool ; Energy charge ; Flower induction ; Leaves ; Photoperiodism ; Spinacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Changes in adenine nucleotides pool size levels have been investigated in spinach leaves (Spinacia oleracea. L. cv. Nobel) in order to characterize the transition from the vegetative to the reproductive development. The transient changes reported in this study are the earliest responses observed to date in leaves during photoperiodic induction. These results are discussed in relation to Prigogine's theory of systems far from equilibrium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385143
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  • 18
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    Viability of Rhizobium leguminosarum endosymbionts in different stages of development (1981)
    Springer
    Archives of microbiology 129 (1981), S. 349-352 
    Details
    ISSN: 1432-072X
    Keywords: Rhizobium ; Bacteroids ; Viability ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Viability of Rhizobium leguminosarum bacteroids isolated from Pisum sativum was determined after sucrose gradient centrifugation of the bacteroids resulting in separation according to developmental stage. The results suggest that past a critical stage of development bacteroids lose viability. Similar experiments with R. japonicum bacteroids having a lower degree of morphological differentiation showed an appreciably higher viability in all gradient fractions. The results support the hypothesis that bacteroid morphology and viability is dependent on the nature of—and length of exposure to—the host plant cytoplasm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406460
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  • 19
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    Insect feeding and oviposition deterrents from western red cedar foliage (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 39-48 
    Details
    ISSN: 1573-1561
    Keywords: Insect feeding deterrents ; antifeedants ; Pissodes strobi Peck ; Coleoptera ; Curculionidae ; Thuja plicata Donn
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The feeding deterrent activity of fractions from the foliage of western red cedar,Thujaplicata Donn, was studied in laboratory bioassays using the white pine weevil,Pissodes strobi Peck, as a test insect. The most active fraction was the volatile mixture that comprises the leaf oil of this tree species. Further fractionation of the leaf oil indicated feeding deterrent activity in the monoterpene hydrocarbon, thujone, and terpene alcohol fractions. When tested alone, both (−)-3-isothujone and (+)-3-thujone, which made up 75–88% and 5–10% of the leaf oil, respectively, deterred feeding by the weevils. Western red cedar leaf oil also showed antifeedant activity with the alder flea beetle,Altica ambiens (Le Conte), and served as an oviposition deterrent for the onion root maggot,Hylemya antiqua Meigen. The leaf oil, however, had no inhibitory effect on the feeding of the leaf roller,Epinotia solandriana L., and the red-backed sawfly,Eriocampa ovata L.
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    Photosynthesis under osmotic stress (1981)
    Springer
    Planta 153 (1981), S. 423-429 
    Details
    ISSN: 1432-2048
    Keywords: Chloroplast envelope (permeability) ; Chloroplast stroma enzymes ; Spinacia ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. Increasing the sorbitol concentration in a suspension of intact chloroplasts induced a fast, transient and not very specific efflux of metabolites from chloroplasts to the medium. Stroma proteins were retained by the chloroplasts. 2. Within the first 30 s following hypertonic stress, the chloroplast volume decreased according to the Boyle-Mariotte relation. A subsequent and transient increase suggested some influx of external solute. 3. Dark reactions of intact chloroplasts such as starch degradation and formation of labelled 3-phosphoglycerate from dihydroxyacetone phosphate or ribose-5-phosphate and 14CO2 were inhibited at low water potentials. After chloroplast rupture, the activity of stromal enzymes was decreased by high solute concentrations. Ribulose bisphosphate carboxylase exhibited a decrease of Vmax, while KmCO 2 remained unaltered. With sorbitol, sucrose, glycerol or glycinebetaine, 50% inhibition of enzymes was observed at osmotic potentials between 40 and 50 bar, with ethyleneglycol at about 70 bar. With salts such as KCl, 50% inhibition was found at 15 to 20 bar. 4. A comparison between inhibition of photosynthesis in intact chloroplasts and inhibition of enzymes in stroma extracts by solutes supports the notion that inhibition of photosynthesis at high osmotic potentials is mainly a solute effect. Another factor contributing to inhibition of photosynthesis in isolated chloroplasts is the loss of intermediates and cofactors which occurs during rapid osmotic dehydration.
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    Photosynthesis under osmotic stress (1981)
    Springer
    Planta 153 (1981), S. 416-422 
    Details
    ISSN: 1432-2048
    Keywords: Chloroplast ; Photosynthesis (under stress) ; Protoplast ; Spinacia ; Water stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. Photosynthesis of leaf slices, mesophyll protoplasts, and intact chloroplasts of spinach was inhibited in hypertonic sorbitol solutions. Sorbitol could be replaced by other nonpenetrating osmotica such as sucrose or glycinebetaine. As a penetrating solute, ethyleneglycol was also inhibitory, but osmolarities required for inhibition of photosynthesis were considerably higher than in the case of non-penetrating osmotica.-2. With leaf slices and protoplasts, 50% inhibition by sorbitol was usually observed at osmotic potentials between 25 and 40 bar. With isolated intact chloroplasts, the osmotic potentials producing 50% inhibition varied considerably. Depending on the growth conditions of the plant material, 50% inhibition occurred between 14 and 40 bar. The integrity of the chloroplast envelope as measured by the accessibility of the thylakoid system for ferricyanide was not affected by osmotic stress.-3. Quantum requirements for CO2 assimilation and reduction of 3-phosphoglycerate or nitrite by intact chloroplasts increased under osmotic stress. The increase was larger for CO2 reduction than for reduction of 3-phosphoglycerate or nitrite.-4. In intact chloroplasts, electron transport to methylviologen was not much affected by osmotic stress. Basal electron transport was not stimulated, suggesting absence of uncoupling.-5. The increase in ATP/ADP ratios on illumination of intact chloroplasts was slower at an osmotic potential of 36 bar than at 11 bar.-6. The results indicate that inhibition of photosynthesis is not caused by the sensitivity of a single photosynthetic reaction to increased osmotic potentials. Rather, several reactions are sensitive to water stress. Osmotic stress acts on the photosynthetic apparatus mainly at the level of dark reactions and ATP synthesis, and much less on primary photoreactions or electron transport, between water and the primary oxidant of photosystem I.-7. The different sensitivity of chloroplasts to penetrating and non-penetrating solutes and the observed variability of chloroplast sensitivity to stress suggests that the reduction in water potential is not directly responsible for damage to the photosynthetic apparatus during osmotic stress. Rather, the composition of the chloroplasts appears to be a decisive factor which determines sensitivity or resistance to osmotic stress.
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    Mode of glucan degradation by purified phosphorylase forms from spinach leaves (1981)
    Springer
    Planta 153 (1981), S. 351-361 
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    ISSN: 1432-2048
    Keywords: Amylopectin ; Amylose ; Glucan phosphorylase ; Glycogen ; Maltodextrin ; Spinacia ; Starch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The glucan specifity of the purified chloroplast and non-chloroplast forms of α-1,4-glucan phosphorylase (EC 2.4.1.1) from spinach leaves (Steup and E. Latzko (1979), Planta 145, 69–75) was investigated. Phosphorolysis by the two enzymes was studied using a series of linear maltodextrins (degree of polymerization ≦11), amylose, amylopectin, starch, and glycogen as substrates. For all unbranched glucans (amylose and maltodextrins G5–G11), the chloroplast phosphorylase had a 7–10-fold higher apparent affinity (determined by initial velocity measurements) than the non-chloroplast phosphorylase form. For both enzyme forms, the minimum chain length required for a significant rate of phosphorolysis was five glucose units. Likewise, phosphorolysis ceased when the maltodextrin was converted to maltotetraose. With the chloroplast phosphorylase, maltotetraose was a linear competitive inhibitor with respect to amylose or starch (K i-0.1 mmol 1-1); the inhibition by maltotetraose was less pronounced with the non-chloroplast enzyme. In contrast to unbranched glucans, the non-chloroplast phosphorylase exhibited a 40-, 50-, and 300-fold higher apparent affinity for amylopectin, starch, and glycogen, respectively, than the chloroplast enzyme. With respect to these kinetic properties the chloroplast phosphorylase resembled the type of “maltodextrin phosphorylase”.
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    The occluding junctions of mouse duodenal enterocytes during development (1981)
    Springer
    Cell & tissue research 217 (1981), S. 65-77 
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    ISSN: 1432-0878
    Keywords: Freeze-fracture ; Occluding junctions ; Enterocytes ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The architecture of occluding junctions during the differentiation of the mouse duodenum was studied in freeze-fractured material. Irregular zonulae occludentes (ZO) (Type I) are numerous during fetal life, and are characterized by their irregular width, and by the presence of basal open-ended extensions fused with the discontinuous basal strand of the ZO. Regular ZOs (Type II), typical of the adult villous epithelium, appear after Type I junctions by day 16 of gestation. Two patterns are distinguishable: in the first, parallel strands of ridges and furrows are found without crossing branches; in the second pattern, the junction zone is organized like a network of short branches forming various types of polygons. In fetal and adult mice fasciae occludentes (FO) (Type III) are present on the lateral cell membranes; in unfixed specimens particles are found in the furrows of the E-face and pits on the ridges of the P-face. In fixed tissues, the particles are aligned on the ridges of the P-face. These results indicate that fixation with glutaraldehyde modifies considerably the affinity of junctional particles toward the P-face during the fracture process. Moreover, the presence of numerous large FOs on the lateral cell membranes of enterocytes during late fetal life and in the adult, is possibly related to cell movement along the intestinal villi.
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    URL: http://dx.doi.org/10.1007/BF00233827
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    A Golgi-electron-microscopical study of the structure and development of the lamina ganglionaris of the locust optic lobe (1981)
    Springer
    Cell & tissue research 216 (1981), S. 377-401 
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    ISSN: 1432-0878
    Keywords: Lamina ganglionaris ; Locust ; Neurons ; Development ; Light and electron microscopy ; Golgi study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The gross structure as well as the neuronal and non-neuronal components of the lamina ganglionaris of the locust Schistocerca gregaria are described on the basis of light- and electron-microscopical preparations of Golgj (selective silver) and ordinary histological preparations. The array of optic cartridges within the lamina neuropile — their order and arrangement — and the composition of the cartridges are described. There are six types of monopolar neurons: three whose branches reach to other cartridges and three whose branches are confined to their own cartridges. Retinula axons terminate either in the lamina or the medulla neuropiles. There are three types of centrifugal neurons, two types of horizontal neuron, as well as glia and trachea in the lamina neuropile. The development of the lamina neuropile is described in terms of developing monopolar and centrifugal axons, growing retinula fibres, and composition of the developing optic cartridges.
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    Catecholamine-storing cells in the adrenal medulla of the pre- and postnatal rat (1981)
    Springer
    Cell & tissue research 217 (1981), S. 155-170 
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    ISSN: 1432-0878
    Keywords: Adrenal medulla ; Development ; Acetylcholinesterase ; Small granule cells ; Ultramorphology ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the rat adrenal medulla was studied at the ultrastructural level with particular emphasis placed on early discrimination of different catecholamine-storing cells. The first granule-containing cells, phaeochromoblasts, were seen at day 15 of gestation migrating into the anlage of the cortex. These cells were characterized by a few small granules (80–120 nm in diameter) and a high nuclear to cytoplasmic ratio. Presumably due to differentiation into chromaffin cells, they were no longer present after the eighth postnatal day. Maturation of phaeochromoblasts was indicated by an increase in number and size of their storage granules and a decrease in the nuclear to cytoplasmic ratio. Noradrenaline and adrenaline cell types were first clearly discernible at day 21 of gestation. Another cell type, a giant cell, was also recognized at this stage. In the adult animal, noradrenaline, two morphologically different types of adrenaline, and small granule-containing cells were observed. By applying acetylcholinesterase histochemistry, it was found that at day 17 of gestation a small population of granule-storing cells showed strong positive staining in the endoplasmic reticulum. In the adult animal this cell type was further characterized by small-storage granules. Other chromaffin cells began to show weak staining within the endoplasmic reticulum at day 19 of gestation. This staining appeared more frequently within adrenaline than noradrenaline cells. However, even in the adult animal many cells of both types were completely negative. It is concluded that acetylcholinesterase histochemistry is a useful method for early discrimination of small granule-containing cells in the developing rat adrenal medulla.
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    Postembryonic development of the antennal lobes in Periplaneta americana L. (1981)
    Springer
    Cell & tissue research 215 (1981), S. 563-575 
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    ISSN: 1432-0878
    Keywords: Antennal lobes ; Development ; Sexual dimorphism ; Periplaneta americana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The postembryonic development of the antennal lobes of Periplaneta americana L. was examined with light- and electron-microscopical methods. There is no difference in the number of glomeruli and neurons in the antennal lobes of larval and adult animals. At hatching, the first larva already possesses the adult number of approximately 125 glomeruli and 500 to 560 deutocerebral neurons in the dorsolateral cell group of each antennal lobe. During postembryonic development the volume of the deutocerebral neurons increases three- to fourfold. The glomeruli of the first larva have about 7 % of the volume of the corresponding adult glomeruli. Since number, pattern, and size ratio of glomeruli (with the exception of the macroglomerulus) are constant in all larval stages and adult animals, it is possible to identify individual glomeruli. During the whole postembryonic development the ordinary glomeruli show a continuous volume increase, which parallels the increase in antennal sensory input. The macroglomerulus develops by way of special growth of two to four neuropil units, but not before the last three to four larval stages and only in males. Its growth precedes the formation of antennal pheromone receptors during the final molt; these receptors are known to project into the macroglomerulus. The development of the macroglomerulus in the last larval stages of the male may be caused by a genetically fixed growth program of specific deutocerebral neurons.
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    Development and ageing of etioplast structures in dark grown leaves ofAvena sativa (L.) (1981)
    Springer
    Protoplasma 108 (1981), S. 83-98 
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    ISSN: 1615-6102
    Keywords: Development ; Etioplast ; Prolamellar body ; Protochlorophyll ; Saponin ; Thylakoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Etioplasts of dark grown plants contain a large paracrystalline prolamellar body (PLB) and, attached to this there are prothylakoid membranes (PTs). PLB-tubules inAvena are composed mainly of two saponins and include only a low percentage of other lipids, protochlorophyll(ide) and proteins. Following the development of etioplasts in darkness from the very beginning until plants loose turgescence one can observe marked changes in ultrastructure. In the early stage of development predominantly PTs are seen in small etioplasts. Wide-type PLBs are small. After eight days there is a well developed stage with the well-known big and highly crystalline PLBs, which are connected to many long PT-membranes. After 13 days the PLBs are not significantly changed, while number and length of PTs are strongly reduced. These morphological observations are quantified by measurements of PLB-area and PT-length per plastid section. Saponin content as a marker for PLB-tubules and protochlorophyll(ide)-content as a marker for PT-membranes were measured. Both methods of determination show in good agreement a peak of development for PTs around day 6–7, and for PLBs around 9–10. Beginning senescence affects PT-membranes and PChl(ide) strongly, while saponins resp. PLBs persist better. These results are presented in view of thylakoid formation during greening, starting from the different etioplast stages.
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    Calcium oxalate crystals inOpuntia ficusindica (L.) mill.: Development and relation to mucilage cells — A stereological analysis (1981)
    Springer
    Protoplasma 109 (1981), S. 271-283 
    Details
    ISSN: 1615-6102
    Keywords: Calcium-oxalate crystals ; Development ; Mucilage ; Opuntia ficus-indica ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the succulent tissue ofOpuntia ficusindica development of calcium oxalate crystals was followed from the shoot apex to its base, using stereological analysis. The stereological parameters relating to the crystal cells were compared with those of mucilage cells, of the same tissue. A fairly monotonic relation between the stereological parameters of the two populations was noted. The possible physiological relation between the two cell populations is discussed.
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    Anomalous sex-related inheritance of oviposition rate inCallosobruchus maculatus Fab. (Coleoptera: Bruchidae) (1981)
    Springer
    Behavior genetics 11 (1981), S. 145-151 
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    ISSN: 1573-3297
    Keywords: Bruchidae ; Callosobruchus ; Coleoptera ; nonadditive inheritance ; oviposition behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract As a result of different feeding regimens, two laboratory populations of the beetleCallosobruchus maculatus Fab. developed different rates of oviposition. The behavior of the F1 hybrids cannot be explained with an additive model of inheritance. The unusual pattern of inheritance suggests a sex-related factor(s) and a two-factor interaction.
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    The evolutionary significance of multigermicity in the genusSpinacia (Chenopodiaceae) (1981)
    Springer
    Plant systematics and evolution 137 (1981), S. 57-61 
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    ISSN: 1615-6110
    Keywords: Angiosperms ; Chenopodiaceae ; Spinacia ; S. turkestanica ; S. tetrandra ; Reproduction ; multigermicity ; seedball ; dioecy ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The presence of multigerm seedballs in the chenopodiacious genusSpinacia is noted. In the wild, colonising, and “weedy” dioecious species,S. turkestanica andS. tetrandra, the distribution of a multigerm seedball could effectively overcome the problem posed by isolation of the sexes. The hypothesis is tested assessing the extent of intra-seedball progeny hybridisations and seed production in the two wild species. The success in seed production by intra-seedball progeny crosses suggests that the distribution of such seedball progeny groups permits not only a percentage survival under isolation of these dioecious plants, but also the colonisation of areas outside that of the parent populations.
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    Ultrastructure of the epidermis of adult and embryonic Paravortex species (Turbellaria, Eulecithophora) (1981)
    Springer
    Hydrobiologia 84 (1981), S. 241-252 
    Details
    ISSN: 1573-5117
    Keywords: Turbellaria ; Eulecithophora ; Paravortex ; Cerastoderma ; parasites ; ultrastructure ; epidermis ; embryo capsule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The epidermis and associated structures of adult and embryonic Paravortex cardii and Paravortex karlingi, internal parasites of Cerastoderma edule, have been examined using scanning and transmission electron microscopy. The cellular epidermis of adult Paravortex bears cilia and microvilli which differ in number and distribution between P. karlingi and P. cardii. Cellular organelles include mitochondria, lipid bodies, Golgi bodies, and ultrarhabdites. Epidermal nuclei are located in the proximal portion of the cells. The development of the tegument of embryo Paravortex has been described and a possible origin for the embryo capsule is suggested. These findings are discussed in relation to the phylogenetic status of the Turbellaria in relation to other Platyhelminthes and in the functional adaptation of the epidermis for a parasitic mode of life.
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    The ultrastructure of the eyes in larval and adult polyclads (Turbellaria) (1981)
    Springer
    Hydrobiologia 84 (1981), S. 267-275 
    Details
    ISSN: 1573-5117
    Keywords: Turbellaria ; Polycladida ; epidermal eye ; cerebral eye ; ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Examination of the larvae of Thysanozoon brocchii and Stylochus mediterraneus shows that they have both epidermal and cerebral eyes, while the young worms of Notoplana alcinoi have only cerebral eyes. A description is given of the ultrastructure of both kinds of eyes. The epidermal eye consists of one cup-shaped pigmented cell, whose cavity is filled with lamellae of ciliary origin. A small covering cell is located over the cup-opening. The cerebral eye is made up of three cells: one pigmented cell with ciliary projections and two rhabdomeric-type photoreceptor cells. The cerebral eye in the adult is formed of a pigmented cup without cilia and at least three rhabdomeric-type photoreceptors. A number of remarks of a morpho-onthological nature are presented.
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    Observations on the ultrastructure of the copulatory organ of Archilopsis unipunctata (Fabricius, 1826) (Proseriata, Monocelididae) (1981)
    Springer
    Hydrobiologia 84 (1981), S. 277-285 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Proseriata ; Archilopsis unipunctata ; ultrastructure ; copulatory organ
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The copulatory organ in adult specimens of Archilopsis unipunctata has been studied by transmission electron microscopy. This copulatory organ is of the conjuncta-duplex type with eversible cirrus. The seminal vesicle, lined with a nucleate epithelium, is surrounded by spirally arranged muscles. The fibres are enclosed in a sheath that is continuous with the septum of the bulbus and the basement lamina of the male canal epithelium. Distally to the seminal vesicle the bulbus is filled with the secretory cell-necks of the prostate glands. The male canal shows three different parts: seminal duct, ejaculatory duct and eversible cirrus. At the transition of seminal duct and ejaculatory duct two prostate ducts open into the lumen. The structure of the epithelium lining the different parts of the canal is described. The transition into the cirrus may be recognized by an abrupt change in the thickness, the electron density and the stratification in the basement lamina and by the disappearance of the epithelium absent indeed in the cirrus. The material found inside the cirrus-lumen is different according to the zone considered. The origin of this material and of the cirrus teeth is discussed.
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    The karyotypes of Dugesia species from Spain (Turbellaria, Tricladida) (1981)
    Springer
    Hydrobiologia 84 (1981), S. 45-52 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Tricladida ; Dugesia ; karyology ; Spain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Some species of Planarians, new to Spain, are recorded. Dugesia polychroa, D. sicula, D. iberica and D. gonocephala s. 1. have been investigated karyologically. The former possesses a diploid complement characteristic of the biotype A (2n = 8); the second is diploid with 2n = 18; diploidy and triploidy were found in sexual populations of D. iberica with n = 8. Triploidy occurred in all the asexual strains of the D. gonocephala group with a basic number of either 8 or 9. In this latter case B-chromosomes were occasionally found.
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    The ecology of the Turbellaria with special reference to the freshwater triclads (1981)
    Springer
    Hydrobiologia 84 (1981), S. 87-90 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Tricladida ; ecology ; freshwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To attempt a complete review of turbellarian ecology in the time and space available would result in superficiality. Therefore, I have restricted this account to the four basic ecological processes which have and continue to determine flatworm distribution and abundance. These are: (1) historical or zoogeographical events which permit or prevent a species from reaching a habitat; (2) physiological limitations of the species vis à vis the habitat; (3) access to suitable energy sources and (4) the effects of competition, predation and parasitism, referred to collectively as bionomic processes.
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    Notes on the biology of some psammophile Turbellaria of the Black Sea (1981)
    Springer
    Hydrobiologia 84 (1981), S. 129-130 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Cercyra ; Pseudomonocelis ; ecology ; reproduction ; feeding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The biology of two marine turbellarians, Cercyra hastata (Tricladida) and Pseudomonocelis ophiocephala (Proseriata) has been studied over a period of five years. They are the main components of the biocoenosis of the saccocirrus sand of Sevastopol Bay. These species have a significant role in the processes of secondary production and transformation of the organic matter in the coastal zone.
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    Development of cilia in embryos of the turbellarian Macrostomum (1981)
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    Hydrobiologia 84 (1981), S. 231-239 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Macrostomum ; ultrastructure ; ciliogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Electron microscopy of Macrostomum hystricinum raised in culture shows that ciliogenesis in the worm's epidermal blastomeres begins in embryos 39–41 h old with kinetosomal and de novo genesis of presumptive basal bodies, which are morphologically distinguishable from centrioles of the mitotic apparatus, and proceeds by the migration of basal bodies to the apical plasma membrane of the cells and their production there of ciliary axonemes by an age of 51–53 h when the bastomeres emerge between yolk cells on the embryo's surface. Ciliogenesis continues throughout development with the addition of cilia virtually one by one to the expanding epidermal cells' surfaces. At no time in ciliogenesis are stages seen that might show derivation of these multiciliated cells from the primitive monociliated cell type presumably present in the ancestors of the Turbellaria.
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    Ultrastructural observations on paracnids. I: Coelogynopora axi Sopott (Turbellaria, Proseriata) (1981)
    Springer
    Hydrobiologia 84 (1981), S. 253-257 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Proseriata ; Coelogynoporidae ; ultrastructure ; paracnids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ‘Schlauchdrüsen’ or paracnids of Coelogynopora axi Sopott, 1972 consist of two components: a muscle cell and a secretory cell. The secretory cell is provided with a tube, which bears a border of microvilli. In the normal position the tube is situated in the interior of the secretory cell, and the microvilli stand at the inner side of the tube. After expulsion of the tube the microvilli are situated at its free surface. The evagination takes place in response to chemical stimuli and is effected by the contraction of the myofibrils of the muscle cell. The paracnids are supposed to be mechanisms of defense. However, conformities with nematocysts and spirocysts of the cnidarians do not exist. The paracnids in other species of the Coelogynoporidae, for example in Invenusta paracnida (Karling, 1966) and Carenscoilia bidentata Sopott, 1972 differ from those of C. axi in many details.
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    50 years of turbellarian research (1981)
    Springer
    Hydrobiologia 84 (1981), S. 1-5 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; T. G. Karling ; biography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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    URL: http://dx.doi.org/10.1007/BF00026155
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    Karyological observations on Polyclads (1981)
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    Hydrobiologia 84 (1981), S. 31-44 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Polycladida ; karyology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A karyological analysis of eight species of Polyclads has been carried out. A chromosome number of n = 10 for Stylochus alexandrinus and for Stylochus mediterraneus was ascertained on germinal lines. A chromosome number of 2n = 20 was ascertained from metaphasic plates from regenerative blastemas of Notoplana alcinoi and Leptoplana tremellaris. A karyometric analysis of this last species permitted the reconstruction of an idiogram. An idiogram was also prepared from metaphasic plates of Stylostomum ellipse obtained from early embryonic mitoses. The chromosome number of this species also was 2n = 20. Chromosome numbers of n = 8 and 2n = 16 were ascertained on germinal lines and metaphasic plates of blastemas in Echinoplana celerrima and on germinal lines and early embryonic mitoses of Stylochoplana maculata. Finally the diploid number 2n = 18 was ascertained on metaphasic plates from regenerative blastema of Yungia aurantiaca.
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    Karyological and taxonomic studies of Dugesia japonica Ichikawa et Kawakatsu in the Far East (1981)
    Springer
    Hydrobiologia 84 (1981), S. 53-68 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Tricladida ; Dugesia ; karyology ; taxonomy ; Japan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A review of previous studies on the taxonomy, karyology and chorology of a polymorphic species Dugesia japonica from the Far East is presented. Two subspecies are now known: D. j. japonica (n = 8, 2x = 16, 3x = 24) and D. j. ryukyuensis (n = 7, 2x = 14, 3x = 21). An attempt has also been made to determine the definition of the B-chromosome as LB and SB and the variation of the karyotypes of both subspecies is described. Every known karyotype of D. japonica is classified into six groups (see Table 2). D. japonica from many localities has a diploid karyotype (2x), a triploid karyotype (3x) and an orthoploidic mixoploid karyotype of 2x & 3x. The origin and the karyological significance of these karyotypes are discussed.
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    Physiological adaptations to entosymbiosis in three species of graffillid rhabdocoels (1981)
    Springer
    Hydrobiologia 84 (1981), S. 147-153 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Graffillidae ; entosymbionts ; physiology ; nutrition ; respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three entosymbiotic graffillid rhabdocoels (Paravortex scrobiculariae, P. cardii and Graffilla buccinicola) from marine bivalve and gastropod molluscs show several physiological adaptations to their life-style which are intimately related to the nutritional physiology and ecology of their respective hosts. All three species feed on their hosts' partially digested food plus the cellular debris released at the end of the hosts' own digestive cycle. G. buccinicola supplements this diet by actively removing intact cells from the host's digestive epithelium. Host enzymes, ingested with the food, are utilized for digestion within the flatworms' gut; there is concomitant reduction in the types and amounts of endogenous enzymes and the gastrodermal gland cells characteristically found in free-living species are absent. Food reserves in the three species consist mainly of glycogen, following the pattern seen in other entosymbiotic flatworms (Turbellaria, Digenea, Cestoda); in P. scrobiculariae this primary adaptation, believed to be linked in all entosymbiotes to the ready availability of food and to high fecundity, probably has a secondary function, in relation to anaerobic respiration, of the type found in cestodes. Other adaptive features, closely correlated with host ecology, are the occurrence of a physiologically active haemoglobin in the brain and pharynx of P. scrobiculariae and, in this species and P. cardii, the differential occurrence and distribution of dehydrogenase systems concerned with aerobic respiration (Krebs cycle), the pentose phosphate shunt and anaerobic respiration (glycolysis). P. scrobiculariae and P. cardii are viviparous and the normal provision of yolk for embryonic nutrition is supplemented by direct passage of materials to the later larvae from the parental gut, thus facilitating extended development of the larva until its birth as an immature miniature adult.
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    The phyletic status of the Paludicola (1981)
    Springer
    Hydrobiologia 84 (1981), S. 7-12 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Tricladida ; Paludicola
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Is the assumption of the monophyly of the Paludicola (freshwater triclads) justified? There seems little doubt on morphological grounds of the close relationship between the Planariidae and the Dendrocoelidae but it is difficult to connect, phylogenetically, the Dugesiidae with these groups. A connection between the former and some of the latter has been unknowingly implied by the author in previous papers, thus raising an anomaly since this would mean that the Dugesiidae are not monophyletic. Is it possible that the Dugesiidae and the Planariidae + Dendrocoelidae have arisen independently from marine ancestors? The implications of such a speculation are examined.
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    Japanese beetle (Coleoptera: Scarabaeidae) (1981)
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    Journal of chemical ecology 7 (1981), S. 1-7 
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    ISSN: 1573-1561
    Keywords: Japanese beetle ; Popillia japonica ; Coleoptera ; Scarabaeidae ; sex attractant ; survey lure ; phenethyl propionate ; eugenol ; synergism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A combination of the synthetic sex attractant (R,Z)-5-(1-decenyl) dihydro-2(3H)-furanone with a 3∶7 mixture of phenethyl propionate (PEP) and eugenol (4-allyl-2-methoxphenol) caught significantly morePopillia japonica Newman than either the sex attractant or the mixture did alone. Also, the synthetic sex attractant captured significantly more males than the PEP-eugenol did during the period of heavy adult emergence of the beetles. The two lures were not significantly different in their attractancy to males about a week later and thereafter. A combination of PEP-eugenol and virgin females in the same trap late in the season also significantly increased beetle captures.
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    Interspecific effects of pheromones on the attraction of the bark beetles,Dendroctonus brevicomis andIps paraconfusus in the laboratory (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 9-18 
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    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Ips paraconfusus ; Coleoptera ; Scolytidae ; Pinus ponderosa ; bark beetle ; exo-brevicomin ; frontalin ; myrcene ; verbenone ; ipsenol ; ipsdienol ; cis-verbenol ; attractants ; inhibition ; semiochemicals ; pheromones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Dendroctonus brevicomis was attracted to a mixture of theIps paraconfusus pheromones, ipsenol,cis-verbenol, and ipsdienol at 10−9 g each/μl but was not attracted to these pheromones at higher and lower release rates.I. paraconfusus was not attracted to theD. brevicomis pheromonesexo-brevicomin, frontalin, and myrcene at any release rate tested. Increased release rates of a mixture of the three pheromones ofI. paraconfusus inhibited the attraction ofD. brevicomis to its synthetic pheromones. A mixture of ipsenol + ipsdienol orcis-verbenol alone failed to cause inhibition indicating that at least two of theI. paraconfusus pheromones are required to inhibit the response ofD. brevicomis. The pheromones ofD. brevicomis did not inhibit the attraction ofI. paraconfusus to its pheromones; however, verbenone was a potent inhibitor.
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    Behavior of the lesser grain borerRhyzopertha dominica (Coleoptera: Bostrichidae) (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 33-38 
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    ISSN: 1573-1561
    Keywords: Coleoptera ; Bostrichidae ; Rhyzopertha dominica ; aggregation pheromone ; lesser grain borer ; grain insect pest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Adult males of the lesser grain borer,Rhyzopertha dominica (F.), produce a pheromone that attracts both sexes. The volatiles from males collected on filter paper or Porapak-Q were attractive in two laboratory bioassays. The mating behavior is described and the function of the phen infested with the borer.
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    Host selection behavior of bark beetles (Coleoptera: Scolytidae) attackingPinus ponderosa, with special emphasis on the western pine beetle,Dendroctonus brevicomis (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 49-83 
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    ISSN: 1573-1561
    Keywords: Primary attraction ; tree predisposition ; Dendroctonus ; Ips ; Gnathotrichus ; Pityophthorus ; Coleoptera ; Scolytidae ; Buprestidae ; Verticicladiella ; Pinus ponderosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Detection of weakened hosts from a distance by bark beetles through olfaction was investigated in field experiments. No significant numbers of Scolytidae were attracted to anaerobically treated pine bolts, stem disks, or sugar and ponderosa pine bark including phloem. Treatment of living trees with cacodylic acid induced attacks byDendroctonus brevicomis, D. ponderosae, Ips latidens, Gnathotrichus retusus, andPityophthorus scalptor, beginning two weeks after treatment. There was no significant difference between landing rates ofD. brevicomis andD. ponderosae on screened treated trees and screened controls. There was a significant increase in landing rates ofG. retusus andI. latidens, because both species had penetrated the screen and produced pheromones. Tree frilling alone did not increase the landing rate of bark beetles. Freezing of the lower trunk with dry ice did not increase significantly the landing rate ofD. brevicomis, D. ponderosae, G. retusus, orI. latidens on screened trees, whereas unscreened frozen trees were attacked by all four species. There was no significantly higher landing rate byD. brevicomis, D. ponderosae, I. paraconfusus, I. latidens, G. retusus, orHylurgops subcostulatus on screened trees evidencing symptoms of severe infection by the root pathogenVerticicladiella wagenerii, than on symptornless trees. These experiments show thatD. brevicomis, D. ponderosae, I. paraconfusus, I. latidens, andG. retusus land, apparently indiscriminately, on healthy and stressed hosts. Thus, in these species host discrimination must occur after landing and prior to sustained feeding.
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    An olfactometer for bark beetle parasites (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 359-366 
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    ISSN: 1573-1561
    Keywords: Parasites ; bioassay ; Dendroctonus frontalis ; Coleoptera ; Scolytidae ; olfactometer ; bark beetles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An “H”-type olfactometer was designed and built to test the response of bark beetle parasites to various beetle and tree host odors. The design has several advantages over other types of olfactometers. Strong air currents are not utilized, parasites have free movement in the test chamber, and a concentration gradient of test compound is maintained. Parasites tested in the olfactometer demonstrated strong positive responses to air drawn over logs infested with bark beetle larvae and varied responses to tree host odors.
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    Sexually dimorphic setiferous sex patch in the male red flour beetle,Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae): Site of aggregation pheromone production (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 465-480 
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    ISSN: 1573-1561
    Keywords: Sexual dimorphism ; Tribolium castaneum (Herbst) ; Coleoptera ; Tenebrionidae ; aggregation pheromone ; behavior ; bioassay ; red flour beetle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Evidence for the existence of a male-produced aggregation pheromone secreted from the prothoracic femoral setiferous sex patch ofTribolium castaneum is reported. Both sexes were attracted toca. 60 ng of crude secretion. Males and females perceive the pheromone on the day of emergence while perception differs between the sexes: male response reaches a maximum on day 1 posteclosion, when tested at 〈1, 1, and 30 days; females show a maximum response at 30 days posteclosion. Behavioral responses to pheromone odors and a complex Chromatographic profile are reported.
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    Defensive secretions of new zealand tenebrionids: (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 889-894 
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    ISSN: 1573-1561
    Keywords: α-Pinene ; defensive secretions ; interspecific variation ; limonene ; monoterpenes ; pentadecene ; Artystona sp. ; Coleoptera ; Tenebrionidae ; lichen ; Parmotrema reticulatum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The defensive secretions of four species of the genusArtystona endemic to New Zealand differ from those of other tenebrionids in that they contain α-pinene and limonene, as well as the more characteristic quinones and alkenes. Adults and larvae ofA. obscura, A. erichsoni, A. rugiceps, andArtystona sp. feed on the lichenParmotrema reticulatum (Taylor), but the terpenes are not sequestered from it. The defensive secretions of the four species show some interspecific variation.
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    Effect of mating on terminating aggregation during host colonization in the bark beetle,Ips paraconfusus (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 1135-1147 
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    ISSN: 1573-1561
    Keywords: Ips paraconfusus ; Coleoptera ; Scolytidae ; Pinus ponderosa ; pheromone biosynthesis ; bark beetle ; myrcene ; α-pinene ; ipsenol ; ipsdienol ; cis-verbenol ; myrtenol ; attractants ; pheromones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Attraction of maleIps paraconfusus to male-infested ponderosa pine logs was inhibited by volatiles from logs infested with mated males and females over an 8-day period in the field. The response of females during this time was not significantly inhibited by these volatiles. Synthesis of the male-specific pheromones, ipsenol and ipsdienol, appeared negligible after 8 days in males allowed to mate with 3 females in these logs while males alone contained levels of these pheromones at about half their maximum rate. The decline in pheromone production in mated males appears to result, at least in part, from a reduction in the activity of the biosynthetic system that converts the host monoterpene, myrcene, to ipsenol and ipsdienol. Mating and feeding have apparently no effect on the biosynthetic system that converts the host monoterpene, (−)-α-pinene, to the pheromone,cis-verbenol in either males or females. The reduced production and release of pheromones by males after mating appears to play a major function in the process of terminating the aggregation phase of host colonization.
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    Antifeedant action ofZ-dihydromatricaria acid from soldier beetles (Chauliognathus spp.) (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 1149-1158 
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    ISSN: 1573-1561
    Keywords: Dihydromatricaria acid ; antifeedant ; acetylenic acid ; Chauliognathus pennsylvanicus ; Coleoptera ; Cantharidae ; soldier beetles ; Phidippus ; jumping spider ; bioassay ; defensive secretion ; defensive behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The acetylenic acid,Z-dihydromatricaria acid (DHMA), previously isolated from the defensive secretion ofChauliognathus lecontei, and now shown to occur also inC. pennsylvanicus, is a potent feeding deterrent to jumping spiders (Phidippus spp.). A simple bioassay withPhidippus is described, which is generally applicable to studies dealing with the isolation and evaluation of feeding deterrency of natural products from insects. By use of this assay,Phidippus were shown to be sensitive to as little as 1 μg DHMA, an amount equivalent to less than 2% of the DHMA content ofC. pennsylvanicus.
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    Cuticular hydrocarbons of adults of the cowpea weevil,Callosobruchus maculatus (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 175-182 
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    ISSN: 1573-1561
    Keywords: Hydrocarbons ; n-alkanes ; branched-chain alkanes ; GC-MS ; cuticular wax ; insect ; cowpea weevil ; Callosobruchus maculatus ; Coleoptera ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The composition of the cuticular hydrocarbons of the cowpea weevil,Callosobruchus maculatus (F.), was determined by using combined gas chromatography-mass spectrometry. The hydrocarbons constituted 88% of the cuticular lipids and were composed of four homologous series of alkanes. Mono- and dimethyl branched-chain alkanes made up 83% of the hydrocarbon fraction.
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    Dominicalure 1 and 2: Components of aggregation pheromone from male lesser grain borerRhyzopertha dominica (F.) (Coleoptera: Bostrichidae) (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 759-780 
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    ISSN: 1573-1561
    Keywords: Pheromone ; Rhyzopertha dominica ; lesser grain borer ; Coleoptera ; Bostrichidae ; unsaturated ester ; dominicalure ; 1-methylbutyl (E)-2-methyl-2-pentenoate ; 1-methylbutyl (E)-2,4-dimethyl-2-pentenoate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Volatiles from lesser grain borers,Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae), were collected on Porapak Q, and those from the male beetles were shown to contain two compounds, that were attractive individually and in combination to both sexes. These compounds were identified as (S)-(+)-1-methylbutyl (E)-2-methyl-2-pentenoate and (S)-(+)-1-methylbutyl (E)-2,4-dimethyl-2-pentenoate by spectrometry and comparison with synthesized compounds. The two compounds have been assigned the trivial names dominicalure 1 and dominicalure 2, respectively. Synthesized samples of these compounds, individually and in combination, were effective in trapping both sexes in field studies.
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    Antennal olfactory response of boll weevil to grandlure and vicinal dimethyl analogs (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 919-926 
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    ISSN: 1573-1561
    Keywords: electroantennogram ; boll weevil ; grandlure ; pheromone ; Anthonomus grandis Boh. ; Coleoptera ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Electroantennogram techniques were used to elucidate antennal olfactory response of male and female boll weevils to a dilution series of grandlure, its components, and some vicinal dimethyl analogs. At higher concentrations, response to the mixture of the two aldehyde components of grandlure was significantly higher than to the two alcohol components. Only one vicinal dimethyl analog elicited a significantly higher response than the control. There were no significant differences in response due to sex over all compounds.
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    A comparative study of the food niches of lake-dwelling triclads and leeches (1981)
    Springer
    Hydrobiologia 84 (1981), S. 91-102 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Polycelis ; Dugesia ; Dendrocoelum ; Erpobdella ; Glossiphonia ; Helobdella ; serological technique ; diet ; British lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The food niches of four species of triclads and three species of non-parasitic leeches living in the littoral zone of British lakes of different trophic status were investigated, over one year, using a serological technique. Antisera against ten potential prey groups were employed. The basic data were adjusted to compensate for differences in predator size and seasonal changes in field temperatures. Data on two of the leech species have been presented elsewhere, but comparisons of the diet of all seven predator species are made in this paper. Much overlap in diet between the various predator species occurs, but, with one exception, each of the genera has a major food resource. The Polycelis spp. feed extensively on oligochaetes, Dugesia polychroa on molluscs, Dendrocoelum lacteum on Asellus, Erpobdella octoculata on chironomids and Glossiphonia complanata on molluscs. Helobdella stagnalis is a generalist feeder. Problems of coexistence of the leech species, and of the leech and triclad species are discussed.
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    Oxygen availability, redox and the distribution of some Turbellaria Schizorhynchidae and other forms (1981)
    Springer
    Hydrobiologia 84 (1981), S. 103-112 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; distribution ; oxygen availability ; redox ; phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Records from a considerable number of meiofaunal samples are reexamined in relation to the depth within sediment distribution of various taxa especially Schizorhynchidae and the main turbellarian orders. Frequency and density records in samples with particular oxygen flow rates and redox potentials confirm that the ranges of Schizochilus, Proschizorhynchus and Neoschizorhynchus spp. within these factors may help account for congeneric occurrence within cores. However, statistical analysis of the records is seldom able to confirm apparent differences. There is, for example, a statistically significant difference in distribution in relation to redox potential between the red schizorhynchians Pseudoschizorhynchides ruber, Diascorhynchus rubrus and the red acoelan Paratomella rubra but not in relation to oxygen availability and depth within sediment. On one beach Gnathostomula aff. paradoxa was found at Eh and O2 availability values under which it must be assumed to be living anaerobically. Contingency and other analyses are extended to differences between higher taxa and the results discussed in relation to habitat evolution of the Turbellaria. The suggestion that structural complexity of turbellarians has increased with increased oxygenation of the environment is tentatively supported.
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    The diet of three species of umagillid neorhabdocoel turbellarians inhabiting the intestine of echinoids (1981)
    Springer
    Hydrobiologia 84 (1981), S. 155-162 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Umagillidae ; symbiosis ; nutrition ; Syndisyrinx ; Syndesmis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three species of umagillid turbellarians were found to have different nutritional relationships with their echinoid hosts: Syndisyrinx franciscanus ingests host intestinal tissue and ciliates that are symbiotic in the intestine of the host; Syndesmis dendrastrorum consumes intestinal tissue and materials that have been ingested by the host; an umagillid that closely resembles Syndesmis echinorum subsists entirely on host intestinal tissue.
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    The problem of cell totipotency, dedifferentiation and transdifferentiation in Turbellaria (1981)
    Springer
    Hydrobiologia 84 (1981), S. 171-179 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Tricladida ; cell differentiation ; regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
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    URL: http://dx.doi.org/10.1007/BF00026178
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    Quantitative analysis of cell types during growth, degrowth and regeneration in the planarians Dugesia mediterranea and Dugesia tigrina (1981)
    Springer
    Hydrobiologia 84 (1981), S. 181-194 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Dugesia ; cell types ; growth ; degrowth ; regneration ; maceration-technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A method of tissue maceration (dissociation) of planarian tissues into single cells was used to characterize the basic cell types in the planarians Dugesia mediterranea and Dugesia tigrina, and to determine the total cell number and distribution of cell types during growth, degrowth and regeneration. Using this method, 13 basic cell types have been determined for both species. The total number of cells increases with body length and volume whereas the distribution of cell types is only slightly affected. Growth and degrowth occur mainly through changes in total cell number leaving cell distribution only moderately affected. During regeneration, an increase in neoblast density in the blastema followed later on by increases in nerve cells are the more significant changes detected. These results are discussed in relation to mechanisms of cell renewal, blastema formation and maintenance of tissue polarity.
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    On some commensal Turbellaria of the Canadian East Coast (1981)
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    Hydrobiologia 84 (1981), S. 131-137 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Crustacea ; Mollusca ; commensalism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The brachyurans Chionoecetes opilio and Hyas araneus collected from the east coast of Canada harbour two species of commensal turbellarians. Ectocotyla hirudo (Levinsen) and E. multitesticulata Fleming & Burt are found on the gills and branchial chambers of male and female crabs. The molluscs Crassostrea virginica and Mytilus edulis collected from several locations where they are cultured along the Northumberland strait carry two commensal eulecithophoran turbellarians, both on the gills, viz., Urasloma cyprinae (Graff) and Paravortex gemellipara (Linton), the latter being a new host record. Aspects of the biology and life-history of these turbellarians are discussed, especially in relationship to the biology of their hosts.
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    Reproductive biology of Dugesia sanchezi, a fresh-water planarian from Chile (1981)
    Springer
    Hydrobiologia 84 (1981), S. 163-165 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Dugesia ; karyology ; reproduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dugesia sanchezi reproduces in nature both sexually and by fission. Laboratory cultures have shown that fissioning is controlled by genetic factors. From sexual specimens randomly mated, 105 sexual and five fissiparous offspring were obtained. The former produced almost exclusively sexual descendents while the latter gave rise to fissiparous individuals, although successively many of them became sexual. These ex-fissiparous specimens show a high fertility and their offspring were almost all fissiparous, with the same characteristics displayed by the preceeding fissiparous generation. Some hypotheses are advanced in order to attempt a genetical interpretation of these results.
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    Relationship between variations of cAMP, neuromediators and the stimulation of nucleic acid synthesis during planarian (Polycelis tenuis) regeneration (1981)
    Springer
    Hydrobiologia 84 (1981), S. 195-201 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; regeneration ; cAMP ; neuromediators
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Regenerating planarians of the species Polycelis tenuis have been studied with respect to the two distinct phases which occur during regeneration, viz., the first 24 h involving cellular activation, and the following days when differentiation of the blastema occurs after a period of cellular proliferation. We have studied particularly the biochemical events that control regeneration with respect to the nature of the signals which induce cellular activation, the membrane receptors of these signals, and the consequences of these signals for the cellular metabolism of DNA, RNA and proteins. The roles of neurohormones such as serotonin, dopamine, and noradrenaline are assessed, and a provisional model of the process of cellular activation is proposed which takes account of all the information that is now available concerning planarian regeneration.
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    Morphology of the Turbellaria at the ultrastructural level (1981)
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    Hydrobiologia 84 (1981), S. 213-229 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; morphology ; ultrastructure ; body wall ; nervous system ; protonephridia ; parenchyma ; digestive system ; reproductive system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The paper reviews the following systems: body wall, nervous system, protonephridia, parenchyma, digestive system, reproductive system, and includes a summary of the literature. New information is presented for the catenulid and neoophoran body wall-construction, the kalyptorhynch proboscis, the catenulid and haplopharyngid protonephridial construction, and the prolecithophoran spermatozoon and female germ cell. Examples of new features, as well as examples of how electron microscopy has clarified the relative position of structures and their substructures are given from the subcellular level to the organization of whole organs. Fine structural features linking different turbellarian orders are summarized. They apparently support Karling's (1974) latest assessment of the affinities between the turbellarian orders which is based primarily on light histological data, they add the recognition of a special link between the Macrostomida and Haplopharyngida and they suggest the existence of three main evolutionary lines within the Turbellaria.
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    A new species of freshwater turbellarian from Africa, predatory on mosquitoes: Mesostoma zariae n. sp. (Typhloplanoida) (1981)
    Springer
    Hydrobiologia 84 (1981), S. 19-22 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Typhloplandoe ; Mesostoma zariae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new species of the genus Mesostoma Ehrenberg 1935, M. zariae n.sp. is described and its relationship discussed. The new species belongs to the M. lingua species-group and is characterised by the presence of two kinds of prostate secretions and a pear-shaped penis papilla. It occurs in small standing or slowly running waters at Zaria, Nigeria. It has previously been proven (Mead 1978) that this species is predatory on the aquatic stages of mosquitoes.
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    Contrasting power of the factors for fission and sexuality in a polyploid planarian (1981)
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    Hydrobiologia 84 (1981), S. 167-169 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Dugesia ; reproduction ; karyology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract One of the biotypes of the planarian Dugesia benazzii is triploid in the somatic line, hexaploid in the female line owing to a chromosome set doubling, and diploid in the male line due to a haploid set elimination. In a population of this biotype only 50% of the oocytes are hexaploid, the others being triploid as a results of the lack of set doubling; the male line is always diploid. After a long period of laboratory culture most of the individuals became asexual and fissiparous. Almost all the oocytes of the few specimens which have remained sexual showed triploid complement; B-chromosomes also appeared. These events represent the manifestation of a new genetic background which act upon the two germ lines in different ways and moments. These topics are discussed.
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    Studies on the speciation of Japanese freshwater planarian Polycelis auriculata based on the analysis of its karyotypes and constitutive proteins (1981)
    Springer
    Hydrobiologia 84 (1981), S. 69-77 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; karyology ; mixoploidy ; electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Various kinds of chromosomal polymorphisms or karyotypic variations are found in the Japanese freshwater planarian Polycelis auriculata. Within this species, there are found worms whose chromosome numbers are 2n = 6, 10, 11, 12 and others, and 3x = 6 and 9. There are some which have cells with triploidy and tetraploidy complements (3x = 6 & 4x = 8), and others which have cells with triploidy and hexaploidy complements (3x = 6 & 6x = 12). These worms with such varied karyotypes are usually found in separate habitats, though occasionally they occur together. Electrophoretic analysis of the proteins extracted from the karyotipically different worms which belong to three different local populations shows some dissimilarity in the constitutive proteins according to their karyotypic differences. The results obtained suggest that this species is still in the process of speciation or chromosomal evolution.
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    Cell activation during regeneration of planarians (1981)
    Springer
    Hydrobiologia 84 (1981), S. 203-207 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; regeneration ; neurohormones ; adenylate cyclase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Planarians are a good subject for studies of cell differentiation. Each multicellular organism is maintained by continuous production, differentiation and ageing of cellular elements. Each cell has a specific position defined by specific regional boundaries. After amputating a part of the body this positional information changes, involving, probably, the first range of cellular activation, the activation of membrane receptors. At the same time in an injured organism the level of neurohormones, which can be now coupled with activated receptors, increases. In the opinion of many authors neurohormones act on the regenerative cells through the medium of adenylate cyclase. This enzyme converts ATP to cAMP and by means of this cyclic nucleotide the second range of cellular activation is initiated i.e. changes of activation of cAMP dependent protein kinases. The sequence of these processes plays the principal role in the ensuing cell differentiation.
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    Studies on the speciation of the European freshwater planarians Polycelis nigra and Polycelis tenuis based on the analysis of enzyme variation by means of iso-electric focusing (1981)
    Springer
    Hydrobiologia 84 (1981), S. 79-86 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Tricladida ; Polycelis ; speciation ; Europe ; enzyme variation ; iso-electric focusing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Polycelis nigra Ehrenberg and Polycelis tenuis Ijima differ morphologically and karyologically. No difference, however, was found in the isozyme pattern of malate dehydrogenase and tetrazolium oxidase, indicating a close relationship. Most sibling species differ at half of the loci. It could be deduced that the reproductive behaviour of a single population of Polycelis nigra in a Dutch pond was not panmictic. Two genetically different strains retained their identities during two years of observation. If pseudogamy occurs in this diploid planarian, the presence of heterozygous specimens indicates the absence of a true meiosis. The iso-electrofocusing technique by which these population-genetical studies were carried out, also lends itself to a comparison of overall protein banding patterns. The membrane proteins especially are conservative. The sodium dodecyl sulphate extracted proteins of Polycelis nigra-tenuis, Planaria torva and Phagocata vitta were very similar, while their water soluble proteins were not. This technique may be of great help in taxonomic studies of the higher taxa.
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    Sand dwelling Turbellaria from the Netherlands Delta area (1981)
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    Hydrobiologia 84 (1981), S. 113-127 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; meiobenthos ; fauna composition ; taxonomy ; Netherlands Delta area
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sand dwelling Turbellaria from the Delta of the Rivers Rhine, Meuse and Scheldt have been investigated. Thirty-eight samples taken from littoral and sublittoral stations in the Grevelingen, Eastern and Western Scheldt have been analysed. Thirty-three species were recorded (Acoela were not considered); twenty-four of them are new for the area and seven new species are described. Density and diversity of Turbellaria were higher in the Eastern Scheldt than in the Western Scheldt or in the Lake Grevelingen. A maximum density of 82 ind./100 cm3 was noted. A tentative calculation on relative abundance of the representatives of the different Turbellaria orders is established. Proseriata seem to be dominant in the localities studied.
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    New England Coelogynoporidae (1981)
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    Hydrobiologia 84 (1981), S. 139-145 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Proseriata ; Coelogynoporidae ; taxonomy ; New England
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Eleven species of the proseriate turbellarian family Coelogynoporidae have been encountered between Cape Cod, Mass. and the southern shore-line of New Brunswick, Canada. The distributions of Coelogynopora schultzii, C. biarmata and Cirrifera cirrifera are reported. Four new species belonging to the genus Coelogynopora, one new species of Cirrifera and a species belonging to a new genus are described. Two species remain undescribed. Biological observations on a laboratory-reared colony of C. biarmata maintained since 1978 are reported.
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    Paravortex karlingi sp. nov. from Cerastoderma edule L., in Britain (1981)
    Springer
    Hydrobiologia 84 (1981), S. 23-30 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Neorhabdocoela ; Paravortex ; parasites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Paravortex karlingi sp. nov. collected from the intestine of the bivalve mollusc Cerastorderma edule from the Ythan Estuary, N. E. Scotland, and elsewhere, is distinguished from a closely related species, P. cardii, also occurring in this host, on the basis of differences in habitat occupied by the two species as well as behavioural and morphological differences. P. karlingi is smaller, has fewer embryos in the gravid adult and shows a different behaviour pattern when released from the host intestine. It is also negatively phototactic whereas P. cardii is initially positively phototactic, only later becoming negatively phototactic. The occurrence of both species in Britain is briefly described.
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    The geographical and bathymetrical distribution of the Fecampiidae (Turbellaria, Rhabdocoela) (1981)
    Springer
    Hydrobiologia 84 (1981), S. 13-16 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Rhabdocoela ; Fecampiidae ; parasites ; crustaceans ; distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract All members of the Fecampiidae are endoparasites. Since 1964 when only four species were known, four new species and 11 cocoon types, made by as many unknown species, have been described. The Fecampiidae are distributed in all major oceans from shallow waters to more than 5000 m depth.
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    Adenylate cyclase in regenerating tissues of the planarian Dugesia lugubris (O. Schmidt) (1981)
    Springer
    Hydrobiologia 84 (1981), S. 209-212 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Dugesia lugubris ; regeneration ; ultracytochemistry ; adenylate cyclase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adenylate cyclase (AC) was localized ultracytochemically in certain tissues of the regenerating planarian Dugesia lugubris. Studies were carried out from one hour after injury up to the 5th day of regeneration. It was found that the greatest amount of active AC appears during the initial hours of regeneration in the membranes of the muscle cells near the wound, in the epithelial cells surrounding the wound, and in rhabdite-forming cells and neoblasts.
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    The system of epidermal ciliary rootlets in Turbellaria (1981)
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    Hydrobiologia 84 (1981), S. 240-240 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; Acoela ; ultrastructure ; ciliary rootlets ; glycogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The rootlets of the kinetic cilia form patterns of different types in the different turbellarian subgroups (cf. Rieger 1981). In the Acoela a rather complex system of ciliary rootlets is found in the epidermis (Dorey 1965; Hendelberg & Hedlund 1973; Bedini & Papi 1974). In the acoel Childia groenlandica (Levinsen) the four rootlets of each cilium make contact with those of adjacent cilia at two levels (Hendelberg & Hedlund 1974). Distinct granules are found in the interior of the main rootlets (Hendelberg & Hedlund 1974; Bedini & Papi 1974, Fig. 16) and basal bodies (Silveira 1972; Hendelberg & Hedlund 1974) of the epidermal kinetic cilia of acoels. Similar granules, probably of identical structure, can be seen in nemertodermatids, in the same positions (Tyler & Rieger 1977, Figs. 3 & 6). Such granules were studied in C. groenlandica with histochemical methods adapted for electron microscopy. Like Silveira (1972) I found the granules of the basal bodies to be Thiéry-positive, and thus evidently to be made up of or at least to contain polysaccharide material. The granules of the main rootlets were also found to be Thiéry-positive (Hendelberg 1976). Digestion experiments (Hendelberg & Hellmén 1978 and unpublished results) strongly support the concept that the granules are glycogen beta-particles. We know that cilia can function as kinetic organelles without any rootlets. But we are still uncertain about the function of the rootlets when occurring. Most probably they form an anchorage, a function which may be favoured by branching rootlets making contact with each other. Another function which has been discussed is the transmittance of impulses regulating the ciliary beat. Glycogen granules represent an energy deposit. The functional implication of these granules in the interior of the ciliary rootlets and basal bodies is not clear. However, the observations raise the question of how energy is transmitted to the cilia. Are the ciliary rootlets, when occurring, involved? This question will be further discussed, with references, in a future full report on the digestion experiments (to be published elsewhere).
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    Ultrastructure of the eye of Urastoma cyprinae (Turbellaria, Alloeocoela) (1981)
    Springer
    Hydrobiologia 84 (1981), S. 276-276 
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    ISSN: 1573-5117
    Keywords: Turbellaria ; ultrastructure ; eye ; Urastoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Urastoma cyprinae (Graff) is a microturbellarian which has been recorded both as a free-living organism by Westblad (1955) and Marcus (1951) and as a commensal in various lamellibranch molluscs (see Burt & Drinnan 1968). The material used in this study came from oysters, Crassostroea virginica, collected off the coast of Prince Edward Island, in which hosts it occurs in large numbers especially during the summer months when the oysters are spawning (Fleming et al. 1981). When U. cyprinae is exposed to light as happens, for example, when an oyster is opened, it shows a marked negative phototactic response. Preliminary work on the fine structure of the photoreceptors in U. cyprinae shows that the two eyes each consists of: (1) a single cup cell full of relatively large, electron-dense pigment granules; (2) a tripartite conical lens system; and (3) what appear to be two photosensitive rhabdomes. The pigment cup cell has a single, well defined nucleus situated basally and close to the membrane of the pigment cell furthest away from the rhabdomeres. The lens system consists of a cone made up of three, separate but equal, parts. Each part has two, flat inner surfaces which join at an angle of 120°, an outer rounded surface, and a rounded upper surface. When these three parts fit together, the cone-shaped lens is formed with the apex of the lens within the ‘cup’ of the pigment cell and the rounded, convex, broad end of the cone lying more or less at the same level as the top of the pigment cup and below the epidermis layer. The rhabdomeres lie between the electron dense lenses and the inside of the pigment cup. They show connections to the visual cells which are bipolar: one extension joining the rhabdomeres; the other constituting the axon which extends into the centrally situated brain or into the longitudinal, lateral nerves. The axons that enter the brain, form connections with other axons from the other eye. The axons that extend posteriorly in a lateral position, presumably play a role in facilitating the avoidance reaction. The chemical nature of the unusual lens has not yet been determined. This is presently under investigation and will be reported later at which time our work will be discussed in relation to other types of rhabdomeric eyes in the Turbellaria.
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    Ethyl decanoate as a major component in the defensive secretion of two new zealand aleocharine (staphylinidae) beetles—Tramiathaea cornigera (broun) andThamiaraea fuscicornis (broun) (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 197-202 
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    ISSN: 1573-1561
    Keywords: Tramiathaea cornigera ; Thamiaraea fuscicornis ; Aleocharinae ; Coleoptera ; Staphylinidae ; defensive secretion ; ethyl decanoate ; esters ; undecane ; toluquinone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The defensive secretions of bothTramiathaea cornigera andThamiaraea fuscicornis contain undecane, toluquinone, ethyl decanoate and smaller amounts of other esters. The presence of esters particularly ethyl decanoate as a major component sets these two beetles apart chemically not only among the staphylinids but also within the subfamily Aleocharinae.
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    Interruption of response ofDendroctonus brevicomis to its attractive pheromone by components of the pheromone (1981)
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    Journal of chemical ecology 7 (1981), S. 183-196 
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    ISSN: 1573-1561
    Keywords: Pinus ponderosa ; Dendroctonus brevicomis ; western pine beetle ; attractant ; interruption ; behavior ; pheromone ; Coleoptera ; Scolytidae ; exo-brevicomin ; frontalin ; myrcene ; verbenone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The catch of the western pine beetle,Dendroctonus brevicomis, at an attractive source of racemicexo-brevicomin, racemic frontalin, and myrcene was reduced by surrounding the source with a grid of 48 stations releasing all three compounds together, orexo-brevicomin alone or myrcene alone. Each compound was released at the rate of 2 mg/24 hr/station. The catch at an attractive bolt cut from a tree being colonized byD. brevicomis was not reduced byexo-brevicomin, but was reduced by the combination ofexo-brevicomin, frontalin, and myrcene in one of two tests. When a transect of traps was placed across a 0.81-hectare plot at six of the 48 stations releasing all three compounds, more beetles were caught at outer than at inner traps. More beetles were caught at unbaited traps on trees in a plot when the three compounds were released than when onlyexo-brevicomin or no compounds were released. A few trees were attacked byD. brevicomis in some of the plots. The antiattractant verbenone released from 48 stations at the rate of 4 mg/24 hr/station did not reduce the catch at an attractive tree bolt.
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    Feeding and boring behavior of the bark beetle,Ips paraconfusus, in extracts of ponderosa pine phloem (1981)
    Springer
    Journal of chemical ecology 7 (1981), S. 209-220 
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    ISSN: 1573-1561
    Keywords: Ips paraconfusus ; Coleoptera ; Scolytidae ; phloem ; ponderosa pine ; host selection ; feeding stimulants ; extracts ; bark beetle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract MaleIps paraconfusus Lanier bored and fed in cellulose powder substrates treated with solvent extracts of ponderosa pine phloem in preference to cellulose powder alone. Stimuli that elicit boring and feeding behavior occurred in the water extracts and the combined solvent extracts. No significant boring or feeding occurred in the methanol extract. There was a preference for, but no significant feeding in, the water partition of the ether extract. Feeding, but no preferential boring, occurred in the ether extracts.
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    A scanning electron microscopic study of larval development in the marine polychaete, Galeolaria caespitosa Lamarck (Serpulidae) (1981)
    Springer
    Cell & tissue research 215 (1981), S. 171-179 
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    ISSN: 1432-0878
    Keywords: Polychaeta, Serpulidae ; Gamete ; Larva ; Development ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Gametes and developing larvae of the polychaete Galeolaria caespitosa were examined by scanning electron microscopy. The sperm display a primitive morphology. When treated with 0.33 M CaCl2, they release a branched acrosomal process. At spawning, the polygonal oocytes have a granular surface made up of spherules and the tips of microvilli. The oocyte coat develops a ridged appearance as the oocyte rounds up. At fertilization, the microvilli are withdrawn from the coat surface. Microvilli again appear on the coat surface during the trochophore stage, but the egg coat appears to be retained as the larval cuticle until the demersal stage. The surface of the larva now shows many microvilli. Details of the organization of several ciliary structures are clarified. Moreover, the present study shows rapid, sequential development of paired setal sacs, with the most anterior pair appearing first.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236257
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    The development of the stomach in Clarias lazera and the intestinal absorption of protein macromolecules (1981)
    Springer
    Cell & tissue research 215 (1981), S. 397-415 
    Details
    ISSN: 1432-0878
    Keywords: Stomach ; Epithelium ; Teleost ; Development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the stomach of the teleost, Clarias lazera, during the early posthatching period, is described, and the developing stomach is compared with that of adult Clarias. The stomach develops in two distinct parts: the corpus, which differentiates first, and the pylorus. The corpus contains a mucous surface epithelium, arranged in folds, and a tubular gland system containing only one type of gland cell, to which the secretion of pepsinogen and HCl is attributed. The pyloric region does not contain tubular glands. From the ultrastructure of the gland cells, the 3H-thymidine labeling index, and the onset of acid production (as determined with pH indicators) it is concluded that a functional stomach is present in juveniles with a standard length of ± 11 mm (approximately 12 days after fertilization at 23–24° C). The ultrastructure of the intestinal epithelium has also been studied. The intestine consists of three segments, similar to those described for stomachless teleosts and a number of fish larvae. In larvae as well as in juveniles, the enterocytes of the second segment show pinocytosis of horseradish peroxidase, although in the juveniles the stomach has already developed. This second segment has the same relative length in all studied larvae and juveniles and is also present in adult Clarias. It is therefore concluded that the capacity to absorb protein macromolecules is not specifically related to the absence of a functional stomach in this teleost species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239123
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  • 82
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    The nervous system of Microstomum lineare (Turbellaria, Macrostomida) (1981)
    Springer
    Cell & tissue research 218 (1981), S. 375-387 
    Details
    ISSN: 1432-0878
    Keywords: Nervous system ; Turbellaria ; Synaptic contacts ; Release of neurosecretory material
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of release sites of neurochemical messenger substances in the microturbellarian Microstomum lineare was examined. Aminergic neurites form conventional synapses and synapse-like structures (SLS). Variants of true synapses include: “single” synapses with symmetric pre- and postsynaptic densities, “shared” synapses, i.e., contacts between 1 pre- and 2 postsynaptic fibres, en passant synapses between parallel axonal membranes, and synapses without thickenings having only clustered vesicles in the presynaptic terminal. SLS on a nerve cell soma or facing an intercellular stromal channel near muscles are described. Peptidergic neurites containing large granular vesicles (LGV) form synaptoids and signs of putative neurosecretory release. Synaptoids between neurites and between neurite and muscle have lucent vacuoles (about 100nm) and dense material at the contact site. In en passage synaptoids dense-core vesicles are embedded in electron-dense material at the contact site. Putative signs of release of neurosecretory material other than “typical” exocytosis have been observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210351
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  • 83
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    The development of the diencephalic choroid plexus in the chick (1981)
    Springer
    Cell & tissue research 219 (1981), S. 297-311 
    Details
    ISSN: 1432-0878
    Keywords: Choroid plexus (chick) ; Third ventricle ; Ependyma ; Development ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The surface morphology of the diencephalic choroid plexus (Pl. ch. v. III) was investigated by light microscopy and scanning electron microscopy in chicks from the 7th embryonic day (ED) to the 8th week after hatching. Pl. ch. v. III develops on the anterior ventricular roof from a sagittally oriented fold and a few posteriorly located transverse folds. On the 7th ED no significant differences in the cell surface morphology between Pl. ch. v. III and the surrounding ependyma are observed: both are covered with cilia. During the next four days, long cell prolongations (one per cell) covered with microvilli develop first on the surface of the posterior ventricular roof and then on the posterior part of Pl. ch. v. III. These structures are transitory. On the 11th ED, round cell prolongations (one per cell) appear progressively on the entire plexus, also replacing the long ones. Now the plexus surface is distinct from the surface of the surrounding ependyma. During the last week before hatching and also after hatching, the round cell prolongations become less prominent. Simultaneously, the number of cilia per unit surface area diminishes. With consideration of earlier reports, this study suggests that the following factors are involved in the increase of the surface area of Pl. ch. v. III: (I) The pseudostratified epithelium changes into columnar epithelium. (2) Ependymal elements of the posterior roof of the 3rd ventricle contribute to the anlage of Pl. ch. v. III. In later stages, however, Pl. ch. v. III grows only by mitoses.
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    URL: http://dx.doi.org/10.1007/BF00210150
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  • 84
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    Morphologic development of neonatal rat pinealocytes in monolayer culture (1981)
    Springer
    Cell & tissue research 220 (1981), S. 337-347 
    Details
    ISSN: 1432-0878
    Keywords: Pineal ; Monolayer culture ; Development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological development of pinealocytes maintained in monolayer culture, without the neural and humoral effects present in the developing rat has been studied and compared with the development that occurs in vivo. Pinealocytes in 5 day cultures contained organelles that were similar to those present in the pineals of intact 5 day old rats. However, light and dark cells were not noted in culture, and the cultured cells did not have the dense granules noted in vivo. As pinealocytes developed in culture, cytoplasmic processes increased in length and number. By 21 days of culture age, synaptic ribbons were found to have decreased in number, the difference between light cell and dark cell cytoplasm had become more prominent, and dense-cored vesicles had become more numerous, just as in the developing gland in vivo. These results suggest that the complex neural and humoral factors impinging upon the developing neonatal pineal in the intact animal may not be necessary for some aspects of its ultrastructural differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210513
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  • 85
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    Development of blood-cerebrospinal fluid barrier to horseradish peroxidase in the avian choroidal epithelium (1981)
    Springer
    Cell & tissue research 214 (1981), S. 271-278 
    Details
    ISSN: 1432-0878
    Keywords: Blood-CSF barrier ; Blood-brain barrier ; Horseradish peroxidase ; Choroid plexus ; Development ; Chick embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The penetration of horseradish peroxidase (HRP) from blood into ventricle via the avian choroid plexus was examined by electron microscopy in order to study the development of the blood-cerebrospinal fluid barrier (BCSFB). 1–20 mg HRP was injected into the allantoic vein of chick embryos between the 7th and 21st day of incubation. Until the 8th day (stage 34) the reaction products of injected HRP were observed in the interepithelial clefts at both luminal (ventricular) and abluminal sides. At the 9th day (stage 35), their penetration was blocked at most apical junctional complexes of the choroidal epithelia. At the 10th day (stage 36) and at every subsequent stage, HRP molecules were completely impeded at the apical tight junctions. These results show that the BCSFB to HRP in the avian choroidal epithelium is completely established by the 10th day, when molecules of HRP are still able to permeate between the capillary endothelia in the cerebellum and the spinal cord (Wakai and Hirokawa 1978).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249211
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  • 86
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    Supraependymal cell clusters in the rat brain (1981)
    Springer
    Cell & tissue research 218 (1981), S. 41-58 
    Details
    ISSN: 1432-0878
    Keywords: Supraependymal cell clusters ; Ventricular system ; Development ; Hypothalamus rat ; Monosodium glutamate ; Androgenized rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The histological patterns of supraependymal cell clusters (CC) in rats of different ages (untreated, androgenized, and treated with monosodium glutamate) were investigated with light (LM)-, scanning-and transmission electron microscopy (SEM, TEM). These clusters were a frequent but not a constant finding. In 18 day-and older embryos, CC were always found in the recess of the olfactory bulb immediately prior to its obliteration. All other CC appear in the infundibular recess between the 3rd and the 6th postnatal day. Independent of age, all cell clusters exhibit small aggregates of subependymal tissue protruding through the ependyma. Both neurons (light cells) and neuroglia (dark cells) were found in the CC. By use of SEM, in the region of the infundibular recess it is possible to distinguish four forms of supraependymal cell clusters according to localization, size, number of cells, and presence of intraventricular axons. CC may be 1) receptors or have an additional secretory function; 2) manifestations of a pathological type of reaction of the ventricular wall; 3) possible excrescences of the neural matrix, or 4) modifications of the ventricular wall in relation to the obliteration of the ventricular recesses. The first two interpretations are not tenable based on the present observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210090
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  • 87
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    The mature mesonephric nephron of the rabbit embryo (1981)
    Springer
    Cell & tissue research 221 (1981), S. 431-442 
    Details
    ISSN: 1432-0878
    Keywords: Kidney (rabbit) ; Development ; Mesonephric nephron ; Freeze-fracture electron microscopy ; Intercellular junctions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In freeze-fracture replicas of the entire cross-fractured mesonephros of 18 day rabbit embryos the basolateral and luminal cell faces of the different nephron segments were studied and compared with their metanephric counterparts. In the proximal tubule, the shallow zonula occludens exhibited only 1–2 strands and resembled the corresponding metanephric zonula, a very “leaky” type, which was found with a considerable paracellular flow component in sites of isotonic reabsorption. Gap junctions were restricted to the proximal tubule and were seen more frequently in its terminal segment. The distal tubule harboured two types of tight junctions. The most common type, a band of 5–8 closely parallel strands, matched the zonula occludens of the metanephric straight distal tubule. The observed particle density of the basolateral membrane (2,500±328/μm2) was less than that of the proximal tubule (2,642±306). In addition, the collecting tubule exhibited a zonula occludens of the “tight” variety similar to that which occurred in the metanephric collecting duct. Rod-shaped particles of the luminal membrane were mainly concentrated in some of the intercalated cells but also had developed on principal cells, and occasionally, in the distal tubule. The Wolffian duct, with a deep “tight” zonula occludens, had an obviously rather inactive epithelium with no conspicuous transport-linked membrane specializations.
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    URL: http://dx.doi.org/10.1007/BF00216746
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