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  • sediment  (29)
  • Drosophila  (23)
  • Springer  (52)
  • Blackwell Publishing Ltd
  • 1980-1984  (52)
  • 1925-1929
  • 1982  (52)
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Keywords
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  • 1980-1984  (52)
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    On the relation between genetic and environmental variability in animals (1982)
    Springer
    Journal of molecular evolution 18 (1982), S. 310-314 
    Details
    ISSN: 1432-1432
    Keywords: Neutral mutation theory ; Natural selection ; Protein evolution ; Levene model ; Environmental variability ; Genetic variability ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary If a phenotypic character is under stabilizing selection, the selective disadvantage of a nonoptimal genotype will decrease exponentially to zero as the proportion of phenotypic variation that is environmental in origin -V e /V p - increases. Under the modified mutation-drift hypothesis of genetic polymorphism, the proportion of mutations that are effectively neutral and average heterozygosity should increase with this ratio. Invertebrates, because of their small size, fast development, and low degree of homeostasis (relative to vertebrates), are expected to show a larger environmental component of phenotypic variation than vertebrates. This may help explain why invertebrates are in general more genetically variable than vertebrates and why, when laboratory populations ofDrosophila are maintained in heterogeneous environments, genetic variability is lost less rapidly than when they are kept in constant conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01733897
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  • 2
    Electronic Resource
    Electronic Resource
    Correlation between adult transformation and aldehyde oxidase staining pattern in wing discs ofApterous genotypes inDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 285-288 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; homoeosis ; Compartments ; Aldehyde oxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The aldehyde oxidase staining pattern in wing discs ofDrosophila melanogaster bearing the genotypesap blt /ap blt andap blt andap blt /ap 73n showns changes from the wild-type pattern. Extensive areas of the presumptive dorsal posterior wing blade, which are normally unstained, have enzyme activity in these mutants. In wings of these genotypes, dorsal posterior structures are replaced by dorsal anterior wing structures. A strong correlation has been found between the frequencies of various staining patterns in the discs and the extent of transformation in the cuticular structures of the wing, which is consistent with the idea that aldehyde oxidase activity can be used as an indicator in the wing disc of this transformation. Unlike the homoeotic mutationengrailed, apterous has not been interpreted as a selector gene yet the work reported here shows thatapterous alleles can cause changes resembling those of theengrailed phenotype both in aldehyde oxidase staining behaviour and in the cuticular transformation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848418
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of the “sexcombless” chromosome (In(1)sx) on males and females ofDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 264-269 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Sexcombless ; Foreleg basitarsus ; Genital disc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The chromosome which carries the mutationsexcombless (In(1)sx) affects males and females ofD. melanogaster. In the male foreleg basitarsi the number of sexcomb teeth is dramatically reduced from 10 to 0.7 and the number of transverse rows of bristles is increased from 6 to 8. Females homozygous forIn(1)sx show a normal bristle pattern in the foreleg basitarsus. The genital disc derivatives of both male and femaleIn(1)sx flies are strongly affected. While the external genitalia show a duplicated or a reduced bristle pattern, the internal genitalia are mostly absent. However, the sexually dimorphic tergites and sternites of the abdomen remain unaffected. The male-specific effect on the basitarsus and the general effects on the genital disc derivatives are proposed to represent two different phenotypic effects ofIn(1)sx which may derive from mutations at different gene loci in the inverted chromosome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848414
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  • 4
    Electronic Resource
    Electronic Resource
    Growth is required for cell competition in the imaginal discs ofDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 289-291 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Cell competition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Imaginal wing discs from late third-instar larvae were gammairradiated to induce clones of rapidly growingMinute − cells in a background of slowly growingMinute cells and culturedin vivo for periods up to 18 days. Clones in discs cultured for 16 to 18 days did not grow significantly larger than clones in uncultured controls, indicating that competition between populations of cells having potentially different mitotic rates does not occur in imaginal discs after their growth is completed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848419
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  • 5
    Electronic Resource
    Electronic Resource
    Sequential gene activation by ecdysteroids in polytene chromosomes ofDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 103-111 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Polytene Chromosomes ; Ecdysteroids ; Fat Body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Changes in polytene chromosome 3 L puffing patterns in the fat body ofDrosophila melanogaster larvae and prepupae are compared to those in the salivary gland. While some general features are common to the two tissues, there are differences which reflect their different developmental roles. In vitro experiments with fat body chromosomes show that they have a distinct response to ecdysteroids which is different from that of salivary gland chromosomes, and which does not,in this culture system, reproduce the changes observed in normal development. In short term culture experiments, the fat body chromosomes appear more sensitive to ecdysteroids than the salivary gland chromosomes and, although 20-OH ecdysone is more active than ecdysone in these assays, the possibility is not excluded that ecdysone has a role in normal development as it appears to alter gene activity at physiological levels in these cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848447
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  • 6
    Electronic Resource
    Electronic Resource
    Homologies of positional information in thoracic imaginal discs ofDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 293-300 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Imaginal discs ; Positional information ; Homology ; Intercalary regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The regulative behavior of fragments of the imaginal discs of the wing and first leg was studied when these fragments were combined with fragments of other thoracic imaginal discs. A fragment of the wing disc which does not normally regenerate when cultured could be stimulated to regenerate by combination with certain fragments of the haltere disc. When combined with a haltere disc fragment thought to be homologous by the criteria of morphology and the pattern of homoeotic transformation, such stimulated intercalary regeneration was not observed. Combinations of first and second leg disc fragments showed that a lateral first leg fragment could be stimulated to regenerate medial structures when combined with a medial second leg disc fragment but not when combined with a lateral second leg disc fragment. Combinations of wing and second leg disc fragments showed that one fragment of the second leg disc is capable of stimulating regeneration from a wing disc fragment while another second leg disc fragment fails to stimulate such regeneration. It is suggested that absence of intercalary regeneration in combinations of fragments of different thoracic imaginal discs is a result of homology or identity of the positional information residing in the cells of the fragments. The pattern of correspondence of positional information revealed by this analysis is consistant with the pattern of homology determined by morphological observation and by analysis of the positional specificity of homoeotic transformation among serially homologous appendages. The implications of the existence of homologous positional information in wing and second leg discs which share a common cell lineage early in development are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848488
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  • 7
    Electronic Resource
    Electronic Resource
    Gap junctions are non-randomly distributed inDrosophila wing discs (1982)
    Springer
    Development genes and evolution 191 (1982), S. 335-339 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Gap junction ; Wing disc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The distribution of gap junctions in mature larvalDrosophila melanogaster wing discs was analyzed by means of quantitative electron microscopy. Gap junctions are non-randomly distributed in the proximal-distal disc axis and in the apical-basal cell axis of the epithelium. In the epithelial cells, the surface density, number and length of gap junctions are greatest in the apical cell region and distal disc region. The average gap junction surface density is 0.0572 μm−1 and 2.77% of the lateral cell surface is composed of gap junctions. In the adepithelial cells, the gap junction surface density is 0.0005 μm−1 and 0.06% of the cell surface is composed of gap junctions. No gap junctions were observed between epithelial cells and adepithelial cells. The absolute area of gap junctions was estimated in a proximal-distal strip of cells in the disc and is considerably less in the folded regions of the epithelium compared to the flat notum and wing pouch regions. The results are discussed with respect to pattern formation and growth control in imaginal discs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848494
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  • 8
    Electronic Resource
    Electronic Resource
    Dicephalic — ADrosophila mutant affecting polarity in follicle organization and embryonic patterning (1982)
    Springer
    Development genes and evolution 191 (1982), S. 28-36 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Polarity ; Maternal effect ; Nurse cells ; Embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationdicephalic (dic) affects follicle development and thereby alters the antero-posterior polarity of embryonic patterning. It maps at a single locus (3–46.0±1.0) and can be characterized as a semi-dominant maternal effect mutation with low penetrance. Indic follicles, the 15 nurse cells form two clusters located at opposite poles of the oocyte; the numerical distribution of the nurse cells among the clusters varies from 7:8 to 1:14. Thedic egg shell carries a micropyle (anterior marker) at either pole, but the misshapen respiratory appendages are restricted to one of the two poles in most eggs. The malformed eggs rarely yield larvae and these are always abnormal anteriorly and/or posteriorly. The segment pattern expressed in their cuticle may represent two anterior parts of opposite polarities (double head type), two posterior parts of opposite polarities (double abdomen type, rare) or show uniform polarity. Lability of organization at the cystocyte stage appears as the primary developmental defect of the mutant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848543
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  • 9
    Electronic Resource
    Electronic Resource
    A clonal analysis of cell lineage and growth in the male and female genital disc ofDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 42-55 
    Details
    ISSN: 1432-041X
    Keywords: Clonal analysis ; Growth ; Cell lineage ; Genital disc ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary InDrosophila, the terminalia (i.e. internal and external analia and genitalia, except the gonads) are formed by the genital disc. Comparative studies suggested that this disc may have evolved through fusion of the imaginal primordia of the last 3 or 4 abdominal segments. The present report describes the clonal relationships within the complex genital disc. Genetically marked cell clones were induced in male and female embryos and larvae heterozygous for cell marker mutations. 1) Frequencies and sizes of clones suggest that the embryonic disc anlage consists of 14–17 precursor cells: 4–6 for the analia, some 7 for the male genitalia, and 3–4 for the female genitalia. These cells grow exponentially during larval development. 2) In both sexes, the clones were confined to either analia or genitalia, suggesting two separate cell lineages already established at blastoderm. 3) Internal and external genitalia remain in the same compartment at least up to 60 h (end of first instar). 4) A clonal restriction appeared around 84 h (mid second instar), separating a dorsal from a ventral part in the male genitalia. The ventral compartment comprises the ventral part of the lateral plate and clasper, hypandrium, and all internal genitalia. No such boundary was detected in the female. 5) In the female, analia and parovaria originate from the same precursors; another cell lineage forms eighth tergites, vaginal plates, oviduct, receptacle, and spermathecae. 6) In female analia, dorsal and ventral plate share common precursors at least up to 84 h. A medio-lateral boundary may appear at 84 h in the ventral anal plate. No clonal restriction was found in the male analia. 7) At all times, clones could cross between left and right sides of the symmetrical terminalia; they consistently did so via ventral structures. 8) The results are discussed in a phylogenetic context, and we propose that the clonal relations reflect the evolution of the complex genital disc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848545
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  • 10
    Electronic Resource
    Electronic Resource
    Maternal effects of zygotic mutants affecting early neurogenesis inDrosophila (1982)
    Springer
    Development genes and evolution 191 (1982), S. 191-201 
    Details
    ISSN: 1432-041X
    Keywords: Neurogenic mutants ; Maternal effects ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The size of the neurogenic region ofDrosophila melanogaster is under the control of several genes of zygotic expression. Lack of function from any of those genes produces an increase of the size of the neurogenic region at the expense of the epidermal anlage. However, differences exist in the extent of neuralisation achieved by each of the genetic loci upon mutation. The present results show that in the case ofN andmam phenotype differences are due to different contributions of maternal gene expression. This could be shown by studying the phenotype which appeared in mutant embryos when the oocytes developed from homozygous mutant precursor cells. Clones of mutant cells were induced in the germ line of females heterozygous for the neurogenic mutationin trans over germ line dependent, dominant female sterile mutations. After removing maternal information the phenotype ofN andmam mutants became identical in both cases. Furthermore maternal information fromN + was found to be necessary for viability of the wildtype.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848335
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  • 11
    Electronic Resource
    Electronic Resource
    Clonal analysis ofsex-lethal, a gene needed for female sexual development inDrosophila melanogaster (1982)
    Springer
    Development genes and evolution 191 (1982), S. 211-214 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Clonal analysis ; Sex determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mutationSxl f , located on the X-chromosome, is a sex-limited recessive lethal that specifically kills 2X; 2A flies while it does not affect X; 2A flies (Cline 1978). We have analyzed the role ofSxl f on sex determination by a clonal analysis of a new spontaneous allele,Sxl fLS . Female embryos and larvae heterozygous forSxl fLS were irradiated at different times of development to generate homozygousSxl fLS clones which were recognized by linked marker mutations. We have studied the phenotype of such clones on sexually dimorphic regions of the fly (foreleg basitarsus, 5th, 6th and 7th tergites, analia and external genitalia). Despite their female (2X; 2A) chromosomal constitution, clones homozygous forSxl fLS differentiated male structures. These results confirm and extend the preliminary report of Cline (1979). They show that the wildtype product ofSxl f is required for female development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848339
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  • 12
    Electronic Resource
    Electronic Resource
    Tissue-specific and substrate-specific detection of aldehyde and pyridoxal oxidase in larval and imaginal tissues of Drosophila melanogaster (1982)
    Springer
    Biochemical genetics 20 (1982), S. 315-332 
    Details
    ISSN: 1573-4927
    Keywords: aldehyde oxidase ; pyridoxal oxidase ; tissue specificity ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The substrate specificities of aldehyde and pyridoxal oxidases in Drosophila melanogaster have been determined with a variety of aliphatic and aromatic aldehydes. This analysis has led to the discovery that 2,4,5-trimethoxy-benzaldehyde is a specific substrate for pyridoxal oxidase, as based on the histochemical distribution of oxidase activity, the absence of enzymatic activity in the lpo 1strains, and the dosage dependence on the number of lpo +genes present. The tissue-specific localization of aldehyde oxidase (AO) and pyridoxal oxidase (PO) in the larval and adult structures showed that AO was present in all the major internal organs of the larvae and adults, including brain, imaginal discs, Malpighian tubules, digestive system, and reproductive structures. Pyridoxal oxidase is present in many of the same structures which possess AO, but is missing from the cardia, crop, imaginal discs, ovarian follicle cells, paragonia, pericardial cells, and wreath cells. The only structure which possesses PO but lacks AO is the larval salivary gland. These histochemical differences in AO and PO distribution were also confirmed by enzymatic analysis of the activities present in homogenates of ovaries, paragonia, and salivary glands. The general pattern of enzyme expression appears to be established during embryogenesis and maintained throughout the life of the individual.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484427
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  • 13
    Electronic Resource
    Electronic Resource
    Selection at the α-Gpdh locus in experimental populations of Drosophila melanogaster (1982)
    Springer
    Biochemical genetics 20 (1982), S. 461-474 
    Details
    ISSN: 1573-4927
    Keywords: Drosophila ; allozymes ; α-Gpdh ; selection ; genetic background
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three sets of experiments have been conducted in order to evaluate the role of natural selection at the α-Gpdh locus in Drosophila melanogaster. (1) The evolution of the F-allele frequency has been followed for many generations in 13 experimental populations having different genetic backgrounds. (2) Egg-to-adult viability has been measured in synthetic populations derived from one locality (Brouilly) and the results have been compared with those of a previous experiment involving a different local population (Tostes). (3) The effects of sodium octanoate on egg-to-adult viability have been measured on the genotypes FF, FS, SF, and SS. The results demonstrate that selection operates on a small block of genes which includes the α-Gpdh locus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484697
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  • 14
    Electronic Resource
    Electronic Resource
    An esterase duplication in Drosophila: Differences in expression of duplicate loci within and among related species (1982)
    Springer
    Biochemical genetics 20 (1982), S. 929-942 
    Details
    ISSN: 1573-4927
    Keywords: esterase ; duplication ; gene expression ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An esterase duplication is described in the sibling species pair Drosophila mojavensis and Drosophila arizonensis. We present evidence for two separate structural loci mapping at a distance of less than 0.16 recombination units from each other. Alleles at the two loci have the same substrate specificities and form small amounts of interlocus heterodimers. One locus (Est-5) is functioning throughout the insect's life cycle and appears at high concentrations in the hemolymph and the fat body. Its duplicate (Est-4) functions only during the late larval stage and is concentrated mainly in the carcass. No null alleles at either locus were observed in population surveys. An examination of 12 other species from the repleta group, to which D. mojavensis and D. arizonesis belong, suggests that Est-5 is universally present, but the activity levels of Est-4 vary among species and may be totally absent in some species. Variation in the level of Est-4 activity does not closely follow the phylogenetic relationship.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484070
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  • 15
    Electronic Resource
    Electronic Resource
    The association between malathion resistance and acetylcholinesterase in Drosophila melanogaster (1982)
    Springer
    Biochemical genetics 20 (1982), S. 179-198 
    Details
    ISSN: 1573-4927
    Keywords: acetylcholinesterase ; Drosophila ; malathion ; insecticide resistance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The relationship between the 50% survival time for flies feeding on a malathion-containing medium and the activity of acetylcholinesterase (AChE) was determined for 15 isofemale lines of Drosophila melanogaster. A significant correlation was found (r=0.28, P〈0.05), with more resistant lines tending to have a lower level of AChE activity. An association between AChE and malathion resistance was also observed in a selection experiment. The AChE activity decreased in two of two populations selected for malathion resistance. AChE from these populations was altered in kinetic parameters (measured in crude head extracts) and electrophoretic mobility. Although the “resistant” AChE had a lower activity (V m) on either a per milligram protein or a per individual basis, its apparent K m for acetylthiocholine was lower than that of “susceptible” AChE. Recombination mapping of both low activity and fast electrophoretic mobility localized these traits to the region of the structural locus (Ace) on the third chromosome. The AChE activity of flies heterozygous for a variety of Ace lesions (kindly provided by Dr. W. M. Gelbart) was consistent with this location. The changes in AChE were suggested to have been caused by selection of alleles at the Ace locus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484945
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  • 16
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    Electronic Resource
    Genetic, ontogenetic, and tissue-specific variation of dipeptidases in Drosophila melanogaster (1982)
    Springer
    Biochemical genetics 20 (1982), S. 407-424 
    Details
    ISSN: 1573-4927
    Keywords: dipeptidases ; Drosophila ; variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Three dipeptidases in Drosophila melanogaster are under independent genetic control and their structural genes have been localized, Dip-A to 2R and Dip-B and Dip-C to 3R (Voelker and Langley, 1978; Ohnishi and Voelker, 1981). These enzymes were characterized with respect to their substrate specificities, genetic variability (electrophoretic mobility and quantitative activity level), ontogeny (activity and isozyme pattern), and tissue localization. The dipeptide substrate specificities of DIP-A and DIP-B overlap each other considerably, but do not overlap with DIP-C. In natural populations, DIP-B and DIP-C are essentially monomorphic electrophoretically whereas DIP-A is polymorphic for three allozymes. Both DIP-A and DIP-B show quantitative genetic variation of activity level within an allozyme class. All three enzymes are expressed at all stages in the life cycle, but DIP-A and DIP-B activities vary considerably according to developmental stage and sex of adult. The tissue localizations of DIP-A and DIP-B activities show similar patterns and a nearly ubiquitous occurrence of both enzymes, but with particularly high values in larval and adult midguts and in the adult female reproductive system. These results suggest a general metabolic role for the enzymes, such as regulation of the concentrated pools of amino acids and oligopeptides found in Drosophila tissues.
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    URL: http://dx.doi.org/10.1007/BF00484692
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  • 17
    Electronic Resource
    Electronic Resource
    Selection at the alcohol dehydrogenase locus of Drosophila melanogaster: Effects of ethanol and temperature (1982)
    Springer
    Biochemical genetics 20 (1982), S. 681-688 
    Details
    ISSN: 1573-4927
    Keywords: alcohol dehydrogenase ; Drosophila ; selection ; ethanol ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Drosophila melanogaster larvae were subjected to 10 generations of selection on 6% ethanol at 17, 25, and 30°C. For each temperature there was a significant (P〈0.01) increase in the frequency of the Adh isoallele. Controls with no ethanol showed no change in the frequency of the Adh F isoallele. Larvae subjected to stronger selection on 8% ethanol confirmed the results. When adults of various ages were subjected to 16 and 32°C, the ADHF isoenzyme retained its twofold advantage in activity over ADHS regardless of the temperature. The same result was obtained with larvae at 16 and 35°C. Although some effect of temperature was demonstrated, it was concluded that the effect was not strong enough for temperature to be a selective factor under the conditions studied. However, ethanol is a strong selective factor for laboratory populations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00483965
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  • 18
    Electronic Resource
    Electronic Resource
    Underreplication during polytenization? (1982)
    Springer
    Theoretical and applied genetics 63 (1982), S. 193-199 
    Details
    ISSN: 1432-2242
    Keywords: Drosophila ; Polytene nuclei ; Underreplication ; Polytenization ; Cytophotometry ; Heterochromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Recent cytophotometric DNA determinations and results of labeling experiments are compared with results of biochemical experiments concerning larval polytene salivary gland nuclei of Drosophila melanogaster. Recent publications (Dennhöfer 1981; 1982 a, b) demonstrate that methodological errors both in hydrolysis of the DNA before Feulgen reaction and in interpretation of the cytophotometric values give raise to the hypothesis of heterochromatic underreplication during polytenization. It is concluded also that methodological difficulties cause the absence of polytene SAT-DNA in biochemical centrifugation experiments since, because of different solubilities of eu- and heterochromatic DNA, the latter is not resolved in DNA isolation procedures from polytene nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303991
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  • 19
    Electronic Resource
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    Genetic variation for anemotaxis (wind-directed movement) in laboratory and wild-caught populations ofDrosophilia (1982)
    Springer
    Behavior genetics 12 (1982), S. 281-293 
    Details
    ISSN: 1573-3297
    Keywords: anemotaxis ; Drosophila ; habitat selection ; heritability ; wind-directed movement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract Two strains ofDrosophila melanogaster were selected for anemotactic response for six generations—one line for upwind response and one line for downwind response. A realized heritability estimate ofh 2=0.131 ±0.029 was obtained for the upwind response, and a realized heritability estimate ofh 2=0.012±0.014 was obtained for the downwind response. The divergent selection estimate wash 2=0.031±0.013. These values are consistent with previously reported heritability estimates for phototaxis and geotaxis, and serve to suggest that wind-oriented movement can be rapidly modified by selection under different habitat conditions. A comparison of wind response among wild-caught individuals of 11 species shows significant response differences between closely related species. Evaluation of these differences in light of the ecology of the flies suggests that upwind movement occurs among the monophagous species, which must move long distances to find their specific feeding sites, while downwind movement is more typical of polyphagous species. Species which are found in riparian or montane forest conditions showed a general reluctance to move under windy conditions. This corresponds to previous observations on these species and reflects the absence of wind generally encountered by these species during their natural periods of activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01067848
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  • 20
    Electronic Resource
    Electronic Resource
    Diurnal variation in the oxygen uptake of river sedimentsin vitro by use of continuous flow-through systems (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 189-195 
    Details
    ISSN: 1573-5117
    Keywords: sediment ; rivers ; oxygen uptake ; continuous flow-through
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The diurnal exchange of oxygen, over the sediment-water interface, was measured on ‘undisturbed’ sediment cores incubated on the river bank of three reaches in the river Susaa, Denmark. The incubation chambers were equipped with a double pumping system, driving an internal and an external flow, respectively. The internal flow created a unidirectional flow over the sediment surface, with the same velocity as the natural river flow. River water was continuously pumped through the incubation chambers (external flow). Magnetic valves alternately shifted the inlet and outlet water through a registration chamber equipped with an oxygen probe and a temperature transducer (A/D 540, integrated circuit). The potential was amplified and registered every minute on a tape recorder. The rate of exchange of oxygen in the chambers was described by the following equation: $${\text{r - exch(t) = }}\frac{{{\text{flow(t)}}}}{{{\text{volume}}}}{\text{[inlet(t) - outlet(t)] - }}\frac{{{\text{d[outlet(t)}}}}{{{\text{dt}}}}$$ Various methods for the numerical solution of the differential equation were used. Due to a small amount of ‘noise’ on the probes, the cubic spline method gave an unrealistically high variation in the oxygen uptake. A better description was obtained, when a Fourier transformation of the inlet and outlet concentrations of oxygen was made. When 15 Fourier coefficients were used, the r-value of the model was better than 0.996. On permanently dark sediment samples, a hysteresis effect between the oxygen exchange rate and the oxygen concentration and temperature appeared. The exchange rates were lower in periods with increasing oxygen concentration. A minimum in the exchange rate was obtained, before the minimum in the concentration of oxygen and temperature was found. This type of hysteresis could be explained by equilibration in connection with the transient state conditions. The hysteresis was probably enlarged by shifts in the size of the aerobic layer in the sediment. The importance of the hysteresis in oxygen balance models for rivers is discussed.
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  • 21
    Electronic Resource
    Electronic Resource
    The rates of sediment-water exchange of oxygen and sediment bioturbation in Lough Neagh, Northern Ireland (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 377-382 
    Details
    ISSN: 1573-5117
    Keywords: bioturbation ; oxygen ; sediment ; Lough Neagh
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oxygen is transported 30 mm into the sediment at an 8 m depth site in eutrophic Lough Neagh by the irrigational activities of the benthic fauna. Faunal activity also mixes the upper 20 mm of sediment. Sediment oxygen uptake rate, redox potential-depth profile and the chlorophylla concentration were measured in the upper sediment layers from February to November 1979. Chlorophylla input to the sediment, following the Spring phytoplankton maximum, remained in the 0–1 cm sediment layer but did cause the redox potential profile to change from one with potentials around 400 mV in the upper 50 mm to one with a strong gradient over the 0–30 mm region. The start of benthic faunal activity in May caused the chlorophylla to be mixed into the 1–2 cm layer and also caused oxygen to be transported into the sediment at a rate sufficient to change the redox potential back to its initial state. The biodiffusion coefficient for solids in the upper 20 mm was estimated to be 6 × 10−8 cm2 s−1. Oxygen transport in the pore, waters of the upper sediment layers was considered to be best described as advection, caused by the irrigational activities of the benthic fauna.
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    URL: http://dx.doi.org/10.1007/BF00940127
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  • 22
    Electronic Resource
    Electronic Resource
    Available phosphorus in lake sediments in The Netherlands (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 491-500 
    Details
    ISSN: 1573-5117
    Keywords: phosphate ; sediment ; bioassay ; algae ; phosphate fractionation ; NTA extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The amount of phosphorus available to algae in the sediments of four lakes in the western part of the Netherlands has been assessed by means of chemical extraction and bioassay techniques. In addition to direct chemical sediment analyses, extractions were carried out with an NTA column method and a stepwise NH4 Cl-NaOH-HCI shaking method, the latter supposedly separating the weakly bound, the Fe- and Al-bound and the Ca-bound phosphates in the sediments. Bioassays, with sediment as the sole source of P, were made with Scenedesmus quadricauda in modified Skulberg's 28 medium to determine the amount of phosphates available to algae. The average total P concentration of the sediments varied from 0.8 to 3.6 mg P g−1 dry wt and correlated well with the net external P loading of the lakes. Uptake of P by algae in the bioassays varied from 0.4 to 36% — while NTA extracted 36–69% of the total P. The ratio NH4Cl extracted/ NaOH extracted/ HCI extracted phosphates is different from lake to lake, although in all lakes the highest extractions (27–62% of total P) are found in the NaOH fraction. However, in the peaty sediments of these lakes, the NaOH step extracted not only the Fe- and Al-bound phosphates but, also, large amounts of humus compounds. Hence, this fraction also contains non-available organic P. The results are related to soil type and chemical characteristics of the sediments, and compared with data from other authors. A positive correlation was found between phosphate available to algae and NTA- and NaOH-extractable P, but the correlation with total phosphorus was higher. Moreover, algal-extractable P proved to be positively correlated with total iron and clay content and negatively with the amount of organic matter. It is concluded that the sediments in the investigated lakes show great variability and that the chemical extraction techniques cannot replace the bioassays to assess the amount of phosphorus available to algae.
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    URL: http://dx.doi.org/10.1007/BF00000047
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  • 23
    Electronic Resource
    Electronic Resource
    Entrainment, deposition, and transport of fine-grained sediments in lakes (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 31-40 
    Details
    ISSN: 1573-5117
    Keywords: sediment ; entrainment ; deposition ; transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent work on the settling, diffusion, entrainment, and deposition of fine-grained sediments in fresh water is reviewed and synthesized. Particular attention is given to the dependence of these processes on sediment properties such as particle size. The application of this knowledge to the analysis and numerical modeling of sediment transport is also discussed. Much of the work is concerned with the Great Lakes and, more specifically, with the Western Basin of Lake Erie.
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    URL: http://dx.doi.org/10.1007/BF00940094
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  • 24
    Electronic Resource
    Electronic Resource
    Availability of dissolved oxygen in interstitial waters of a sandy creek (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 651-658 
    Details
    ISSN: 1573-5117
    Keywords: stream ; sediment ; sand ; hyporheal ; oxygen ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dissolved oxygen, pH, conductivity and alkalinity of surface and subsurface interstitial waters were investigated at Mill Creek (a small, rural, predominantly sandy stream in east Texas). Dissolved oxygen concentration tended to decrease with sediment depth, while conductivity and alkalinity did not significantly change with substrate depth. Surface water pH was significantly higher than interstitial water (p = 0.05). Chemical analyses of subsurface water from a pre- to post-storm event showed a depression in dissolved oxygen concentration in moderate and deep interstitial waters, immediately following the return of stream base flow, with the deeper strata returning to pre-storm oxygen levels four days later. A thermal convective current mechanism is proposed which would serve to transport surface water downward into these deeper interstices.
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    URL: http://dx.doi.org/10.1007/BF02391980
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  • 25
    Electronic Resource
    Electronic Resource
    Available phosphorus in lake sediments in The Netherlands (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 491-500 
    Details
    ISSN: 1573-5117
    Keywords: phosphate ; sediment ; bioassay ; algae ; phosphate fractionation ; NTA extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The amount of phosphorus available to algae in the sediments of four lakes in the western part of the Netherlands has been assessed by means of chemical extraction and bioassay techniques. In addition to direct chemical sediment analyses, extractions were carried out with an NTA column method and a stepwise NH4 Cl-NaOH-HCI shaking method, the latter supposedly separating the weakly bound, the Fe- and Al-bound and the Ca-bound phosphates in the sediments. Bioassays, with sediment as the sole source of P, were made withScenedesmus quadricauda in modified Skulberg's 28 medium to determine the amount of phosphates available to algae. The average total P concentration of the sediments varied from 0.8 to 3.6 mg P g−1 dry wt and correlated well with the net external P loading of the lakes. Uptake of P by algae in the bioassays varied from 0.4 to 36% — while NTA extracted 36–69% of the total P. The ratio NH4Cl extracted/ NaOH extracted/ HCI extracted phosphates is different from lake to lake, although in all lakes the highest extractions (27–62% of total P) are found in the NaOH fraction. However, in the peaty sediments of these lakes, the NaOH step extracted not only the Fe- and Al-bound phosphates but, also, large amounts of humus compounds. Hence, this fraction also contains non-available organic P. The results are related to soil type and chemical characteristics of the sediments, and compared with data from other authors. A positive correlation was found between phosphate available to algae and NTA- and NaOH-extractable P, but the correlation with total phosphorus was higher. Moreover, algal-extractable P proved to be positively correlated with total iron and clay content and negatively with the amount of organic matter. It is concluded that the sediments in the investigated lakes show great variability and that the chemical extraction techniques cannot replace the bioassays to assess the amount of phosphorus available to algae.
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    URL: http://dx.doi.org/10.1007/BF02391963
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  • 26
    Electronic Resource
    Electronic Resource
    The effect of land use on the diatom communities in lakes (1982)
    Springer
    Hydrobiologia 86 (1982), S. 99-103 
    Details
    ISSN: 1573-5117
    Keywords: diatoms ; lakes ; land use ; sediment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Data on recenr diatom community structure and relevant environmental characteristics from the lakes and their catchments have been collected from 151 oligotrophic lakes in eastern Finland. The pattern of frequency distribution of diatoms as a function of environmental variables, including land use in the catchment, differs between diatom taxa and indicates the optimum conditions and amplitude of occurrence for particular species. This kind of study should lead to increased understanding of the environmental requirements of diatom species and will be useful in the interpretation of historical changes in lakes as well as in forecasting possible future changes.
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    URL: http://dx.doi.org/10.1007/BF00005794
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  • 27
    Electronic Resource
    Electronic Resource
    The rates of sediment-water exchange of oxygen and sediment bioturbation in Lough Neagh, Northern Ireland (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 377-382 
    Details
    ISSN: 1573-5117
    Keywords: bioturbation ; oxygen ; sediment ; Lough Neagh
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oxygen is transported 30 mm into the sediment at an 8 m depth site in eutrophic Lough Neagh by the irrigational activities of the benthic fauna. Faunal activity also mixes the upper 20 mm of sediment. Sediment oxygen uptake rate, redox potential-depth profile and the chlorophylla concentration were measured in the upper sediment layers from February to November 1979. Chlorophylla input to the sediment, following the Spring phytoplankton maximum, remained in the 0–1 cm sediment layer but did cause the redox potential profile to change from one with potentials around 400 mV in the upper 50 mm to one with a strong gradient over the 0–30 mm region. The start of benthic faunal activity in May caused the chlorophylla to be mixed into the 1–2 cm layer and also caused oxygen to be transported into the sediment at a rate sufficient to change the redox potential back to its initial state. The biodiffusion coefficient for solids in the upper 20 mm was estimated to be 6 × 10−8 cm2 s−1. Oxygen transport in the pore, waters of the upper sediment layers was considered to be best described as advection, caused by the irrigational activities of the benthic fauna.
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    URL: http://dx.doi.org/10.1007/BF02391953
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  • 28
    Electronic Resource
    Electronic Resource
    Different patterns of phosphorus release from lake sediments in laboratory experiments (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 415-429 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus release ; sediment ; nitrate ; redox-potential ; sorption ; fractionation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phosphorus release from surface sediments of eight lakes, mainly shallow lakes in agricultural areas, was studied in laboratory batch experiments with additions of acetate and/ or nitrate. The lake sediments could be separated into three categories. Some sediments did not release phosphorus under any conditions. The second category showed a high phosphorus release rate when acetate was added, in order to stimulate bacterial activity and oxygen consumption. The addition of nitrate, only, stabilized the redox conditions and prevented phosphorus release. This pattern followed the classical theories of Einsele and Mortimer. The third sediment category released phosphorus up to some level which remained constant throughout the experiment, and was independent of acetate and/or nitrate additions. Several extraction procedures and adsorption-desorption experiments were performed in order to characterize the sediment phosphorus and thus explain the different behaviours of the three sediment categories.
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    URL: http://dx.doi.org/10.1007/BF02391957
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  • 29
    Electronic Resource
    Electronic Resource
    Hydrocarbon accumulation in freshwater sediments of an urban catchment (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 285-292 
    Details
    ISSN: 1573-5117
    Keywords: PAH ; aliphatic hydrocarbons ; sediment ; stormwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The top and bottom of two sediment cores collected from an urban receiving basin in NW London, and stormwater samples from the attendant catchment, have been analysed for their hydrocarbon content. In surface sediments, basal sediments and stormwater, total aliphatic hydrocarbon levels are 445–690 µg g−1 dry wt., 43–224 µg g−1 and 0.36–1.10 mg l−1, respectively; and total levels of polyaromatic hydrocarbons (PAHs) are 780–1 100 µg g−1, 310–640 µg g1 and 5.83–18.21 mg l−1, respectively. Biodegradation of aliphatics is assessed by phytane:n-C18 and pristane: n-C17 ratios. Hydrocarbon sources are determined from phytane: pristane ratios, odd: even carbon chain length ratios, the presence of an unresolved complex mixture, and by comparison of the amount of methyl-substituted PAH s with that of the parent compounds. Comparison of total levels between surface and basal sediments shows a 1 to 3 fold increase in total PAHs and a 3 to 10 fold increase in aliphatic hydrocarbons over a 120 year period.
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    URL: http://dx.doi.org/10.1007/BF02391945
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    Electronic Resource
    Electronic Resource
    Physical and geochemical characteristics of suspended solids, Wilton Creek, Ontario (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 41-57 
    Details
    ISSN: 1573-5117
    Keywords: biogeochemistry ; rivers ; sediment ; water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To understand the nature of sediment-associated nutrient and contaminant transport dynamics in fluvial systems, a stormflow sampling program of suspended solids is reported for one water year in a representative rural diffuse source catchment of southeastern Ontario. Bulk samples of subsieve suspended solids were obtained using field-portable continuous-flow centrifuge apparatus. The physical and geochemical properties of suspended solids show no significant intersite differences over reaches of 1 500–2 000 m, yet display distinctive seasonal trends. Systematic seasonal changes in particle size, organic content, and Ca, P, Mn, Al, Ti, Fe, and K appear to reflect the changing role of partial area hydrology. Ca, P, and Mn are bioaccumulated by stream algae. Mineral signature is relatively constant over the year.
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    URL: http://dx.doi.org/10.1007/BF00940095
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    Electronic Resource
    Electronic Resource
    Effects of sediment releases from a reservoir on stream macroinvertebrates (1982)
    Springer
    Hydrobiologia 96 (1982), S. 177-184 
    Details
    ISSN: 1573-5117
    Keywords: sediment ; reservoir ; stream ; macroinvertebrates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effects of sediment release from Guernsey Reservoir on macroinvertebrates of the North Platte River, Wyoming, were investigated during summer 1981. Suspended solids concentrations during sediment release increased from 〈20 mg l−1 to 〉300 mg l−1. Because fine particulates remained in suspension, mean particle size of substrates was unaltered. Densities of chironomids decreased 90% + during sediment release but recovered to initial levels in 3 weeks after the release ended. Densities of mayflies and oligochaetes increased. Changes in benthic populations were highly correlated with increases in suspended solids.
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    URL: http://dx.doi.org/10.1007/BF02185433
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  • 32
    Electronic Resource
    Electronic Resource
    Different patterns of phosphorus release from lake sediments in laboratory experiments (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 415-429 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus release ; sediment ; nitrate ; redox-potential ; sorption ; fractionation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phosphorus release from surface sediments of eight lakes, mainly shallow lakes in agricultural areas, was studied in laboratory batch experiments with additions of acetate and/ or nitrate. The lake sediments could be separated into three categories. Some sediments did not release phosphorus under any conditions. The second category showed a high phosphorus release rate when acetate was added, in order to stimulate bacterial activity and oxygen consumption. The addition of nitrate, only, stabilized the redox conditions and prevented phosphorus release. This pattern followed the classical theories of Einsele and Mortimer. The third sediment category released phosphorus up to some level which remained constant throughout the experiment, and was independent of acetate and/or nitrate additions. Several extraction procedures and adsorption-desorption experiments were performed in order to characterize the sediment phosphorus and thus explain the different behaviours of the three sediment categories.
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    URL: http://dx.doi.org/10.1007/BF00000041
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  • 33
    Electronic Resource
    Electronic Resource
    Availability of dissolved oxygen in interstitial waters of a sandy creek (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 651-658 
    Details
    ISSN: 1573-5117
    Keywords: stream ; sediment ; sand ; hyporheal ; oxygen ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dissolved oxygen, pH, conductivity and alkalinity of surface and subsurface interstitial waters were investigated at Mill Creek (a small, rural, predominantly sandy stream in east Texas). Dissolved oxygen concentration tended to decrease with sediment depth, while conductivity and alkalinity did not significantly change with substrate depth. Surface water pH was significantly higher than interstitial water (p = 0.05). Chemical analyses of subsurface water from a pre- to post-storm event showed a depression in dissolved oxygen concentration in moderate and deep interstitial waters, immediately following the return of stream base flow, with the deeper strata returning to pre-storm oxygen levels four days later. A thermal convective current mechanism is proposed which would serve to transport surface water downward into these deeper interstices.
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    URL: http://dx.doi.org/10.1007/BF00000064
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  • 34
    Electronic Resource
    Electronic Resource
    Available phosphorus in lake sediments in The Netherlands (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 491-500 
    Details
    ISSN: 1573-5117
    Keywords: phosphate ; sediment ; bioassay ; algae ; phosphate fractionation ; NTA extraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The amount of phosphorus available to algae in the sediments of four lakes in the western part of the Netherlands has been assessed by means of chemical extraction and bioassay techniques. In addition to direct chemical sediment analyses, extractions were carried out with an NTA column method and a stepwise NH4 Cl-NaOH-HCI shaking method, the latter supposedly separating the weakly bound, the Fe- and Al-bound and the Ca-bound phosphates in the sediments. Bioassays, with sediment as the sole source of P, were made withScenedesmus quadricauda in modified Skulberg's 28 medium to determine the amount of phosphates available to algae. The average total P concentration of the sediments varied from 0.8 to 3.6 mg P g−1 dry wt and correlated well with the net external P loading of the lakes. Uptake of P by algae in the bioassays varied from 0.4 to 36% — while NTA extracted 36–69% of the total P. The ratio NH4Cl extracted/ NaOH extracted/ HCI extracted phosphates is different from lake to lake, although in all lakes the highest extractions (27–62% of total P) are found in the NaOH fraction. However, in the peaty sediments of these lakes, the NaOH step extracted not only the Fe- and Al-bound phosphates but, also, large amounts of humus compounds. Hence, this fraction also contains non-available organic P. The results are related to soil type and chemical characteristics of the sediments, and compared with data from other authors. A positive correlation was found between phosphate available to algae and NTA- and NaOH-extractable P, but the correlation with total phosphorus was higher. Moreover, algal-extractable P proved to be positively correlated with total iron and clay content and negatively with the amount of organic matter. It is concluded that the sediments in the investigated lakes show great variability and that the chemical extraction techniques cannot replace the bioassays to assess the amount of phosphorus available to algae.
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    URL: http://dx.doi.org/10.1007/BF00940137
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  • 35
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    Modelling the influence of bioturbation on the vertical distribution of sedimentary phosphorus in L. Esrom (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 197-206 
    Details
    ISSN: 1573-5117
    Keywords: bioturbation ; modelling ; sediment ; phosphorus ; Chironomus anthracinus ; Potamothrix hammoniensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A multilayer sediment-water exchange model was used to evaluate the importance of bioturbation in the profundal sediments of L. Esrom. The temporal variation of the vertical distribution of sedimentary phosphorus fractions was modelled with an objective function of 1.50. Deviations between measured and simulated values occurred in the spring, where the measured pool of sedimentary phosphorus sharply declined in the surface sediments. The application of a model for the activity ofChironomus anthracinus based on biomass, oxygen consumption and temperature improved the model in the spring period. The downwards transport of easy-degradable surface sediments reduced the average release of sedimentary phosphorus from 12 mg P · m−2 · day−1 to 11 mg P · M−2 · day−1. The introduction of a similar model for the other important burrowing species in L. Esrom,Potamothrix hammoniensis, lowered the objective function to 1.37 and increased the average release to 12.5 mg P · m−2 · day−1. The minor role of bioturbation in sediment processes is discussed.
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    URL: http://dx.doi.org/10.1007/BF00940110
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    Electronic Resource
    Electronic Resource
    Hydrocarbon accumulation in freshwater sediments of an urban catchment (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 285-292 
    Details
    ISSN: 1573-5117
    Keywords: PAH ; aliphatic hydrocarbons ; sediment ; stormwater
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The top and bottom of two sediment cores collected from an urban receiving basin in NW London, and stormwater samples from the attendant catchment, have been analysed for their hydrocarbon content. In surface sediments, basal sediments and stormwater, total aliphatic hydrocarbon levels are 445–690 µg g−1 dry wt., 43–224 µg g−1 and 0.36–1.10 mg l−1, respectively; and total levels of polyaromatic hydrocarbons (PAHs) are 780–1 100 µg g−1, 310–640 µg g1 and 5.83–18.21 mg l−1, respectively. Biodegradation of aliphatics is assessed by phytane:n-C18 and pristane: n-C17 ratios. Hydrocarbon sources are determined from phytane: pristane ratios, odd: even carbon chain length ratios, the presence of an unresolved complex mixture, and by comparison of the amount of methyl-substituted PAH s with that of the parent compounds. Comparison of total levels between surface and basal sediments shows a 1 to 3 fold increase in total PAHs and a 3 to 10 fold increase in aliphatic hydrocarbons over a 120 year period.
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    URL: http://dx.doi.org/10.1007/BF00940119
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  • 37
    Electronic Resource
    Electronic Resource
    Physical and geochemical characteristics of suspended solids, Wilton Creek, Ontario (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 41-57 
    Details
    ISSN: 1573-5117
    Keywords: biogeochemistry ; rivers ; sediment ; water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To understand the nature of sediment-associated nutrient and contaminant transport dynamics in fluvial systems, a stormflow sampling program of suspended solids is reported for one water year in a representative rural diffuse source catchment of southeastern Ontario. Bulk samples of subsieve suspended solids were obtained using field-portable continuous-flow centrifuge apparatus. The physical and geochemical properties of suspended solids show no significant intersite differences over reaches of 1 500–2 000 m, yet display distinctive seasonal trends. Systematic seasonal changes in particle size, organic content, and Ca, P, Mn, Al, Ti, Fe, and K appear to reflect the changing role of partial area hydrology. Ca, P, and Mn are bioaccumulated by stream algae. Mineral signature is relatively constant over the year.
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    URL: http://dx.doi.org/10.1007/BF02391921
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  • 38
    Electronic Resource
    Electronic Resource
    Modelling the influence of bioturbation on the vertical distribution of sedimentary phosphorus in L. Esrom (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 197-206 
    Details
    ISSN: 1573-5117
    Keywords: bioturbation ; modelling ; sediment ; phosphorus ; Chironomus anthracinus ; Potamothrix hammoniensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A multilayer sediment-water exchange model was used to evaluate the importance of bioturbation in the profundal sediments of L. Esrom. The temporal variation of the vertical distribution of sedimentary phosphorus fractions was modelled with an objective function of 1.50. Deviations between measured and simulated values occurred in the spring, where the measured pool of sedimentary phosphorus sharply declined in the surface sediments. The application of a model for the activity ofChironomus anthracinus based on biomass, oxygen consumption and temperature improved the model in the spring period. The downwards transport of easy-degradable surface sediments reduced the average release of sedimentary phosphorus from 12 mg P · m−2 · day−1 to 11 mg P · M−2 · day−1. The introduction of a similar model for the other important burrowing species in L. Esrom,Potamothrix hammoniensis, lowered the objective function to 1.37 and increased the average release to 12.5 mg P · m−2 · day−1. The minor role of bioturbation in sediment processes is discussed.
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    URL: http://dx.doi.org/10.1007/BF02391936
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    Convection in bottom sediments and its role in material exchange between water and sediments (1982)
    Springer
    Hydrobiologia 86 (1982), S. 105-108 
    Details
    ISSN: 1573-5117
    Keywords: convection ; sediment ; temperature ; convectional diffusion ; material exchange
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In two Finnish lakes, in winter and summer, a constant temperature in the sediment was not reached until a depth of 1.5–2 m. The thermal stratification pattern in the sediment was similar to that in water. However, the lack of turbulent mixing in the sediment resulted in a thin ‘episediment’. This stratification was caused by convection. Convection currents in the sediment were most prevalent during spring and autumn overturn when the density of overlying water was greater than that of the interstitial water. Convection was also possible in winter. The duration and magnitude of convection was dependent on warming and cooling rates. Such convection currents may be important in material exchange between sediment and water since material concentrations in interstitial water are 5–100 times greater than in overlying water.
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    URL: http://dx.doi.org/10.1007/BF00005795
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  • 40
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    Effects of the burrowing mayfly, Hexagenia, on nitrogen and sulfur fractions in lake sediment microcosms (1982)
    Springer
    Hydrobiologia 87 (1982), S. 273-283 
    Details
    ISSN: 1573-5117
    Keywords: Hexagenia ; sediment ; sulfur ; nitrogen ; bioturbation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Effects of the burrowing mayfly, Hexagenia, on nitrogen and sulfur fractions of sediment, and overlying water were determined. Laboratory microcosms were used to reproduce the benthic environment. The activities of Hexagenia increased sediment Eh (1.98 ± 0.486 (22) mV · day −1), and decreased pH in sediment (−0.007 ± 0.001 (22) day −1) and overlying water(-0.024 ± 0.004 (10) day−1). In the control, Eh decreased and pH did not change. The presence of Hexagenia also markedly increased ammonia in sediment (5.46 ± 0.14 (22) ppm N · day−1) and overlying water (0.792 ± 0.154 (10) ppm N · day−1), while the control did not change. In addition, the sulfate fraction of sediment (0.177 ± 0.006 (17)% dry mass) and water (50.0 ± 4.9 (5) mg · I−1) in microcosms with Hexagenia was greater than that of the control (0.151 ± 0.005 (16)% dry mass; 14.7 ± 1.71 (3) mg · 1−1) at the termination of the experiment. Hexagenia may also stimulate the mineralization of carbon-bonded sulfur. The general role of Hexagenia in altering sediment chemistry is discussed.
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    URL: http://dx.doi.org/10.1007/BF00007235
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  • 41
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    The rates of sediment-water exchange of oxygen and sediment bioturbation in Lough Neagh, Northern Ireland (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 377-382 
    Details
    ISSN: 1573-5117
    Keywords: bioturbation ; oxygen ; sediment ; Lough Neagh
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Oxygen is transported 30 mm into the sediment at an 8 m depth site in eutrophic Lough Neagh by the irrigational activities of the benthic fauna. Faunal activity also mixes the upper 20 mm of sediment. Sediment oxygen uptake rate, redox potential-depth profile and the chlorophyll a concentration were measured in the upper sediment layers from February to November 1979. Chlorophyll a input to the sediment, following the Spring phytoplankton maximum, remained in the 0–1 cm sediment layer but did cause the redox potential profile to change from one with potentials around 400 mV in the upper 50 mm to one with a strong gradient over the 0–30 mm region. The start of benthic faunal activity in May caused the chlorophyll a to be mixed into the 1–2 cm layer and also caused oxygen to be transported into the sediment at a rate sufficient to change the redox potential back to its initial state. The biodiffusion coefficient for solids in the upper 20 mm was estimated to be 6 × 10−8 cm2 s−1. Oxygen transport in the pore, waters of the upper sediment layers was considered to be best described as advection, caused by the irrigational activities of the benthic fauna.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000037
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  • 42
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    Accumulative phases for heavy metals in limnic sediments (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 269-284 
    Details
    ISSN: 1573-5117
    Keywords: heavy metals ; sediment ; concentrates ; extraction ; availability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Data from mechanical concentrates of recent sediments indicate that clay minerals, clay-rich aggregates and heavy minerals are the major carriers of heavy metals in detrital sediment fractions. Hydrous Fe/Mn oxides and carbonates and sulfides, in their specific environments, are the predominant accumulative phases for heavy metals in autochthonous fractions. Sequential chemical extraction techniques permit the estimation of characteristic heavy metal bonding forms: exchangeable metal cations, easily reducible, moderately reducible, organic and residual metal fractions, whereby both diagenetic processes and the potential availability of toxic compounds can be studied. The data from lakes affected by acid precipitation indicate that zinc, cobalt and nickel are mainly released from the easily reducible sediment fractions and cadmium from organic phases. In contrast at pH 4.4, neither lead nor copper seem to be remobilized to any significant extent. Immobilization by carbonate precipitation seems to provide an effective mechanism for the reduction of dissolved inputs 9f metals such as zinc and cadmium in pH-buffered, hard water systems.
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    URL: http://dx.doi.org/10.1007/BF00940118
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  • 43
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    Availability of dissolved oxygen in interstitial waters of a sandy creek (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 651-658 
    Details
    ISSN: 1573-5117
    Keywords: stream ; sediment ; sand ; hyporheal ; oxygen ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Dissolved oxygen, pH, conductivity and alkalinity of surface and subsurface interstitial waters were investigated at Mill Creek (a small, rural, predominantly sandy stream in east Texas). Dissolved oxygen concentration tended to decrease with sediment depth, while conductivity and alkalinity did not significantly change with substrate depth. Surface water pH was significantly higher than interstitial water (p = 0.05). Chemical analyses of subsurface water from a pre- to post-storm event showed a depression in dissolved oxygen concentration in moderate and deep interstitial waters, immediately following the return of stream base flow, with the deeper strata returning to pre-storm oxygen levels four days later. A thermal convective current mechanism is proposed which would serve to transport surface water downward into these deeper interstices.
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    URL: http://dx.doi.org/10.1007/BF00940154
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  • 44
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    Entrainment, deposition, and transport of fine-grained sediments in lakes (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 31-40 
    Details
    ISSN: 1573-5117
    Keywords: sediment ; entrainment ; deposition ; transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent work on the settling, diffusion, entrainment, and deposition of fine-grained sediments in fresh water is reviewed and synthesized. Particular attention is given to the dependence of these processes on sediment properties such as particle size. The application of this knowledge to the analysis and numerical modeling of sediment transport is also discussed. Much of the work is concerned with the Great Lakes and, more specifically, with the Western Basin of Lake Erie.
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    URL: http://dx.doi.org/10.1007/BF02391920
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  • 45
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    Diurnal variation in the oxygen uptake of river sedimentsin vitro by use of continuous flow-through systems (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 189-195 
    Details
    ISSN: 1573-5117
    Keywords: sediment ; rivers ; oxygen uptake ; continuous flow-through
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The diurnal exchange of oxygen, over the sediment-water interface, was measured on ‘undisturbed’ sediment cores incubated on the river bank of three reaches in the river Susaa, Denmark. The incubation chambers were equipped with a double pumping system, driving an internal and an external flow, respectively. The internal flow created a unidirectional flow over the sediment surface, with the same velocity as the natural river flow. River water was continuously pumped through the incubation chambers (external flow). Magnetic valves alternately shifted the inlet and outlet water through a registration chamber equipped with an oxygen probe and a temperature transducer (A/D 540, integrated circuit). The potential was amplified and registered every minute on a tape recorder. The rate of exchange of oxygen in the chambers was described by the following equation: $${\text{r - exch(t) = }}\frac{{{\text{flow(t)}}}}{{{\text{volume}}}}{\text{[inlet(t) - outlet(t)] - }}\frac{{{\text{d[outlet(t)}}}}{{{\text{dt}}}}$$ Various methods for the numerical solution of the differential equation were used. Due to a small amount of ‘noise’ on the probes, the cubic spline method gave an unrealistically high variation in the oxygen uptake. A better description was obtained, when a Fourier transformation of the inlet and outlet concentrations of oxygen was made. When 15 Fourier coefficients were used, the r-value of the model was better than 0.996. On permanently dark sediment samples, a hysteresis effect between the oxygen exchange rate and the oxygen concentration and temperature appeared. The exchange rates were lower in periods with increasing oxygen concentration. A minimum in the exchange rate was obtained, before the minimum in the concentration of oxygen and temperature was found. This type of hysteresis could be explained by equilibration in connection with the transient state conditions. The hysteresis was probably enlarged by shifts in the size of the aerobic layer in the sediment. The importance of the hysteresis in oxygen balance models for rivers is discussed.
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    URL: http://dx.doi.org/10.1007/BF02391935
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  • 46
    Electronic Resource
    Electronic Resource
    Accumulative phases for heavy metals in limnic sediments (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 269-284 
    Details
    ISSN: 1573-5117
    Keywords: heavy metals ; sediment ; concentrates ; extraction ; availability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Data from mechanical concentrates of recent sediments indicate that clay minerals, clay-rich aggregates and heavy minerals are the major carriers of heavy metals in detrital sediment fractions. Hydrous Fe/Mn oxides and carbonates and sulfides, in their specific environments, are the predominant accumulative phases for heavy metals in autochthonous fractions. Sequential chemical extraction techniques permit the estimation of characteristic heavy metal bonding forms: exchangeable metal cations, easily reducible, moderately reducible, organic and residual metal fractions, whereby both diagenetic processes and the potential availability of toxic compounds can be studied. The data from lakes affected by acid precipitation indicate that zinc, cobalt and nickel are mainly released from the easily reducible sediment fractions and cadmium from organic phases. In contrast at pH 4.4, neither lead nor copper seem to be remobilized to any significant extent. Immobilization by carbonate precipitation seems to provide an effective mechanism for the reduction of dissolved inputs 9f metals such as zinc and cadmium in pH-buffered, hard water systems.
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    URL: http://dx.doi.org/10.1007/BF02391944
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  • 47
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    Different patterns of phosphorus release from lake sediments in laboratory experiments (1982)
    Springer
    Hydrobiologia 91-92 (1982), S. 415-429 
    Details
    ISSN: 1573-5117
    Keywords: phosphorus release ; sediment ; nitrate ; redox-potential ; sorption ; fractionation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phosphorus release from surface sediments of eight lakes, mainly shallow lakes in agricultural areas, was studied in laboratory batch experiments with additions of acetate and/ or nitrate. The lake sediments could be separated into three categories. Some sediments did not release phosphorus under any conditions. The second category showed a high phosphorus release rate when acetate was added, in order to stimulate bacterial activity and oxygen consumption. The addition of nitrate, only, stabilized the redox conditions and prevented phosphorus release. This pattern followed the classical theories of Einsele and Mortimer. The third sediment category released phosphorus up to some level which remained constant throughout the experiment, and was independent of acetate and/or nitrate additions. Several extraction procedures and adsorption-desorption experiments were performed in order to characterize the sediment phosphorus and thus explain the different behaviours of the three sediment categories.
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    URL: http://dx.doi.org/10.1007/BF00940131
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  • 48
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    Structural and functional characteristics of epiphyton and epipelon in relation to their distribution in Lake Vechten (1982)
    Springer
    Hydrobiologia 95 (1982), S. 79-114 
    Details
    ISSN: 1573-5117
    Keywords: periphyton ; submerged macrophytes ; sediment ; artificial substrates ; oxygen exchange ; production ; decomposition ; sedimentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Epiphyton and epipelon were quantitatively collected, respectively, from the submerged macrophytes and the sandy lake bottom of Lake Vechten (The Netherlands). On a weight basis, epiphyton was maximal in autumn and epipelon in summer. In winter the chemical composition of epiphyton and epipelon was similar. In summer the epiphyton had on a unit weight basis more organic matter and carbonate, and had per unit organic matter a higher algal number, nitrogen and energy content than the epipelon. Algae predominating the epiphyton were filamentous greens and pennate diatoms; those in the epipelon were pennate diatoms and blue-green algae. In both cases, species known to frequent the phytoplankton were abundant. The diatoms were quantified using paper chromatographic pigment analyses. Both the epiphyton and the epipelon exhibited maximal photosynthesis in mid summer. That light was generally the limiting factor was evident from periphyton developed on artificial substrates. This periphyton differed widely in its composition from that on the natural substrates, mainly because the latter collected much more sedimenting matter. In dense Ceratophyllum stands light was severely attenuated and the significant gradients in oxygen and pH were caused by the differences with depth in the proportions of photosynthesis and respiration. The oxygen content and pH at the bottom decreased owing to epipelic respiration. The epiphytic composition depended greatly on the degree of light attenuation. The epiphytic and epipelic respiration, except during part of the early summer, exceeded photosynthesis on a 24 h basis; this included the macrophytic photosynthesis during the time the vegetation was maximally developed. During the growing season import of organic matter, i.e. deposited seston, greatly exceeded that due to the photosynthetic production. After the summer maximum, the epipelon decreased faster than predicted from its oxygen exchange. It was concluded that sedimentation and resuspension determined mainly the changes in epiphyton and epipelon. Especially when covered with vegetation, the lower littoral of Lake Vechten plays a large part in the aerobic decomposition of sestonic organic matter.
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    URL: http://dx.doi.org/10.1007/BF00044478
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  • 49
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    The effects of cytochalasin B and colchicine on the morphogenesis of mitochondria in Drosophila hydei during meiosis and early spermiogenesis (1982)
    Springer
    Cell & tissue research 224 (1982), S. 161-168 
    Details
    ISSN: 1432-0878
    Keywords: Mitochondria ; Meiosis ; Spermiogenesis ; Drosophila ; Organ culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Morphogenesis of mitochondria in male germ cells in cultivated cytocysts begins in early prophase I at which time mitochondria thicken and become ordered along the spindle apparatus during meiosis. At the end of the second meiotic division they aggregate to form the Nebenkern. In the presence of colchicine or cytochalasin B mitochondria are able to begin differentiation, although the correct course of meiosis is not guaranteed. In medium supplemented with colchicine they undergo normal thickening but do not aggregate, in a pattern known from untreated cultures. This may indicate that microtubules are involved in the aggregation process of mitochondria as colchicine is known to inhibit microtubule formation. Moreover, in cell cultures treated with cytochalasin B mitochondrial aggregation does occur; it is concluded that microfilaments, which are sensitive to cytochalasin B, do not play a detectable role in the aggregation of mitochondria.
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    URL: http://dx.doi.org/10.1007/BF00217275
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  • 50
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    Ultrastructural pathology of the compound eye and optic neuropiles of the retinal degeneration mutant (w rdgB KS222) Drosophila melanogaster (1982)
    Springer
    Cell & tissue research 225 (1982), S. 11-22 
    Details
    ISSN: 1432-0878
    Keywords: Transmission and high voltage electron microscopy ; Drosophila ; Degeneration ; Retinular cells ; Optic neuropiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The compound eye and the two most distal optic neuropils (lamina ganglionaris and medulla externa) of the Drosophila mutant w rdgB KS222were examined with transmission electron microscopes at conventional (60 kV) and high (0.8–1 MV) voltages. Eye tissue was sampled in the newly emerged and at 3, 7, and 21 days following eclosion. This mutant is known to show a light-induced degeneration of the peripheral retinular cells (R 1–6); the spectral sensitivity is altered and the threshold is increased reflecting the function of the central cells (R7, 8) which do not degenerate. A totally normal appearing visual system (peripheral retina and optic neuropiles) was found in newly emerged adults. After 3 days the somata of some of the peripheral retinal cells are affected and all of their axons show degeneration. At one week the R 1–6 pathology is well advanced in both somal and axonal regions. In affected cells the cytoplasm is more or less uniformly electron dense and contains liposomes, lysosome-like bodies, myeloid figures and vacuoles suggesting autophagy. Such cytoplasm (noted at 3 and 7 days post-eclosion) exhibits an electron dense reticulum and degenerate mitochondria. Microvilli become more electron dense. Retinular axon terminals are electron opaque and lack synaptic vesicles with few if any presynaptic structures. Mitochondrial remains are barely recognizable. Transsynaptic degeneration was not found. After 3 weeks, the structure of R 1–6 in the peripheral retina (somata and rhabdomeres) is greatly reduced or lost while R7 and R8 and higher order neurons are not affected. The debris from cell bodies and axon terminals of R 1–6 seems diminished, so that some phagocytosis probably takes place along with gliosis in the lamina.
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    URL: http://dx.doi.org/10.1007/BF00216214
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    Comparative study of structure and function of blood cells from two Drosophila species (1982)
    Springer
    Cell & tissue research 221 (1982), S. 607-615 
    Details
    ISSN: 1432-0878
    Keywords: Hemocytes ; Drosophila ; Ultrastructure ; Phagocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hemocytes of Drosophila melanogaster and Drosophila yakuba larvae have been defined in terms of their ultrastructure and functions in “coagulation”, wound healing, encapsulation, phenol-oxydase activity, and phagocytosis. The position of these cells among the classical hemocyte types of insects is determined. We distinguish two plasmatocyte types (macrophage plasmatocytes and lamellocytes) which do not seem to belong to the same lineage, and oenocytoids which are the crystal cells of the literature.
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    URL: http://dx.doi.org/10.1007/BF00215704
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    Autoradiographic studies of protein and polysaccharide synthesis during vitellogenesis in Drosophila (1982)
    Springer
    Cell & tissue research 224 (1982), S. 315-333 
    Details
    ISSN: 1432-0878
    Keywords: Oogenesis ; Vitellogenesis ; Radiolabelling ; Metabolism ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative light- and electron-microscopic autoradiography was used to evaluate metabolic processes that occur during late developmental stages (10–14) of oogenesis in Drosophila melanogaster. Major differences in radiolabelling patterns were found after in vivo (10–45 min) uptake of [3H]-monosaccharides and [3H]-L-lysine. Several different methods of data analysis were required to facilitate interpretation of these patterns. [3H]-L-lysine produced extensive cytoplasmic labelling at all developmental stages. In addition, about 15% of alpha yolk spheres were intensely labelled at stage 10, reflecting the incorporation of radiolabelled vitellogenins synthesized during the incubation period. Subsequent stages showed low silver grain density over alpha yolk spheres until stage 14, when a burst of [3H]-L-lysine incorporation by most alpha spheres was observed, possibly indicative of a maturation process for embryogenesis. [3H]-D-glucose and [3H]-D-galactose (10 min, in vivo) both induced intense labelling of the beta yolk spheres in a manner suggesting in situ assembly beginning at early stage 13. Inasmuch as the polysaccharide of beta yolk spheres has the properties of glycogen (e.g., rosette structure digested by α-amylase) and the radiolabelled monosaccharides were introduced intraabdominally, it is evident that transport systems as well as enzymes utilizing glucose and galactose for glycogenesis must be readily available. It is notable that wide-spread labelling of egg chambers was elicited by [3H]-D-glucose and [3H]-D-galactose (e.g., nurse cells, follicle cells, chorion, vitelline membrane), but the labelling induced by [3H]-N-acetylmannosamine was restricted mainly to the endochorion. A possible role of microtubules in distribution and assembly of yolk spheres was inferred when colchicine, admixed to the culture medium (2–5 ppm), produced abnormal distribution and diminution in number of both alpha and beta yolk spheres. In addition to revealing previously unknown metabolic events of vitellogenesis, the results provide additional criteria for stage characterization as well as a means to specifically label certain macromolecules for purposes of isolation.
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    URL: http://dx.doi.org/10.1007/BF00216876
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