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  • 1
    Digitale Medien
    Digitale Medien
    A sample holder for decomposing and processing delicate biological materials for scanning electron microscopy (1979)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 9 (1979), S. 0 
    Details
    ISSN: 1365-2427
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: SUMMARY. A simple, inexpensive sample holder was developed to permit delicate biological materials (faecal pellets) to be decomposed in aquatic environments and thereafter to be processed by dehydration and critical point drying procedures. Part of the holder itself is used to mount the sample onto specimen studs. Delicate materials are therefore never subjected to physical damage during handling at any stage of their processing for scanning electron microscopy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2427.1979.tb01509.x
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  • 2
    Digitale Medien
    Digitale Medien
    The peritrophic membrane and faecal pellets of Gammarus lacustris limnaeus Smith (1978)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 8 (1978), S. 0 
    Details
    ISSN: 1365-2427
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: SUMMARY. Gammarus lacustris limnaeus Smith was fed decomposed autumnshed leaves of maple (Acer saccharum Marsh.) and poplar (Populus tremuloides Michx.). Faecal pellets were collected at various time intervals after egestion and examined under a light and a scanning electron microscope. Nearly all the faecal pellets collected up to a period of about 7 h after egestion possessed a thin, tightly-fitting peritrophic membrane while those that had been outside the gut of the animal for a longer time lacked a peritrophic membrane. Presumably, after egestion faecal pellets swell because of absorption of water leading to eventual rupture and loss of the membrane. The surface of newly extruded pellets is devoid of microbes and microbes seem to play a very insignificant role in the loss of peritrophic membrane from the pellets.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2427.1978.tb01441.x
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  • 3
    Digitale Medien
    Digitale Medien
    Laboratory experiments on factors affecting the activity of Gammarus pseudolimnaeus Bousfield (1975)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 5 (1975), S. 0 
    Details
    ISSN: 1365-2427
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Factors such as current, light, food, substrate and time of year were found to influence the activity of specimens of Gammarus pseudolimnaeus maintained in stream tanks in the laboratory. Although there was seasonal variation, levels of diurnal and nocturnal activity were generally much higher when there was no current than when the water was running. Diurnal periodicity occurred but was not as pronounced as had been indicated in the field studies of previous workers. Although there was activity during the day, nocturnal levels were higher especially in specimens collected during the summer. When there was no current, and the lights were left on for 24 h, peak activity occurred at precisely the times when the lights normally would have been off. This strongly suggests that there is an endogenous component in the activity. The nocturnal activity showed a bigeminus pattern, and there was a seasonal change, with the general activity at its highest levels in summer. Activity was significantly greater during daylight both with and without current when there was no substrate present in the tanks. The behaviour of Gammarus appears to be complex and greatly influenced by combinations of the various factors.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2427.1975.tb00154.x
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  • 4
    Digitale Medien
    Digitale Medien
    Bis(indenyl)zirconium(IV) complexes of monofunctional bidentate salicylidimines (1983)
    Springer
    Monatshefte für Chemie 114 (1983), S. 907-913 
    Details
    ISSN: 1434-4475
    Schlagwort(e): Bis(indenyl)zirconium(IV) complexes ; Schiff base ; Conductance ; IR ; 1H NMR ; UV-VIS
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wurde eine Reihe von (C9H7)2Zr(SB)Cl-Komplexen synthetisiert, wobeiSB − für das Anion einer zweizähnigenSchiff-Base steht. DieSchiff-Basen sind von Salicylaldehyd und 4-substituierten Anilinen hergeleitet: Salicyliden-4-anisidin,-4-phenetidin, -4-Cl-, -4-Br-, -4-I-anilin und -4-Nitroanilin. Die Synthese erfolgte über die Reaktion von Bis(indenyl)zirkonium(IV)-dichlorid mit derSchiff-Base (SBH) in einem molaren Verhältnis von 1:1 am Rückfluß in Gegenwart von Triethylamin undTHF als Lösungsmittel. Zur Charakterisierung der neuen Derivate wurden Elementaranalysen, Leitfähigkeitsmessungen und spektroskopische Daten (IR,1H-NMR, UV-VIS) herangezogen.
    Notizen: Abstract A series of (C9H7)2Zr(SB)Cl complexes whereSB − is the anion of bidentateSchiff base derived from salicylaldehyde and 4-substituted anilines, viz. salicylidene-4-ansidine, salicylidene-4-phenetidine, salicylidene-4-chloroaniline, salicylidene-4-bromoaniline, salicylidene-4-iodoaniline and salicylidene-4-nitroaniline, have been synthesized by the reaction of bis(indenyl)zirconium(IV) dichloride andSchiff base (SBH) in 1:1 molar ratio in refluxingTHF in the presence of triethylamine. The new derivatives have been characterized on the basis of their elemental analyses, conductance measurements and spectral (IR,1H-NMR, UV-VIS) studies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00799951
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Thin-layer chromatographic separation of copper (II), nickel (II) and cobalt (II) as thiocarbonato-complexes and determination by ring colorimetry (1972)
    Springer
    Chromatographia 5 (1972), S. 326-327 
    Details
    ISSN: 1612-1112
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02310752
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  • 6
    Digitale Medien
    Digitale Medien
    The Toxicity of Margosan-O, a Product of Neem Seeds, to Selected Target and Nontarget Aquatic Invertebrates (1998)
    Springer
    Archives of environmental contamination and toxicology 35 (1998), S. 426-431 
    Details
    ISSN: 1432-0703
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik , Medizin
    Notizen: Abstract. Margosan-O, an insecticide formulated from extracts of neem tree (Azadirachta indica) seed kernels, besides being toxic, also has feeding, oviposition-deterring, and growth-inhibitory effects on insects. This product, registered in the United States for ornamental plants, has been proposed for food crop use. However, little information exists on its effects on aquatic organisms. This study investigated toxicity of Margosan-O to the mosquito Culex spp., a possible target species, and to nontarget species—two crustaceans, Daphnia magna, Hyalella azteca, and a dipteran, Chironomus riparius. The 48-h EC50 value of 105 mg L−1 for Culex spp. was significantly more toxic than for C. riparius (281 mg L−1), not significantly different from D. magna (125 mg L−1) but was significantly less toxic than for H. azteca (71 mg L−1). A concentration of 20–30 mg L−1 caused growth inhibitory effects in Culex spp. and C. riparius larvae and 40 and 84 mg L−1 affected growth and reproduction in H. azteca and D. magna, respectively. Margosan-O may not be suitable for mosquito control since the concentrations required to control emergence may have some nontarget effects. Alternatively, the agricultural application of Margosan-O is also not expected to reduce the survival or produce growth and reproductive effects in nontarget aquatic organisms. However, based on estimated concentrations of less than 10 mg L−1 in adjacent shallow bodies of water and recommendations for repeated applications, there should be concern that the threshold for chronic toxicity is too narrow.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002449900398
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  • 7
    Digitale Medien
    Digitale Medien
    Structural variations in Vicia faba mitochondrial genome (1988)
    Springer
    Theoretical and applied genetics 76 (1988), S. 587-592 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Mitochondrial DNA of plants ; Minicircular ; DNA copy number ; Molecular rearrangements ; Vicia faba
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary A comparative analysis of the presence of minicircular DNA CCCIB in 16 different lines and cultivars of fertile Vicia faba L. plants was conducted. It was found that copy number of CCCIB ranged from several copies per mitochondrial genome to — probably — zero, depending on cultivar or line. Fertility of plants in these cases was not altered. We chose 10 cultivars and lines among 16 analysed. Mitochondria of five cultivars and lines contained about two CCCIB molecules per one CCCIA. The sixth cultivar contained CCCIB at copy number several times lower. In the last four cultivars CCCIB could not be identified. Copy number analysis of CCC2 in ten chosen cultivars and lines revealed that in eight cases the quantitiy of CCC2 was equal to CCCIA. However, two other cultivars contained about two times lower quantity of CCC2. Parallel to that we observed an increase in quantity of one sequence homologous to CCC2, which in the first eight cultivars and lines could be found only in minor quantities. Comparative restriction analysis revealed notable rearrangement events in mitochondrial DNAs of ten cultivars and lines being investigated. We did not find any correlations between patterns of restriction fragments and copy number of CCCIB. In some cases, rearrangements in Vicia faba mitochondrial genomes caused a duplication of sequences homologous to the Zea mays coxII gene.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00260913
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  • 8
    Digitale Medien
    Digitale Medien
    The Toxicity of a Neem Insecticide to Populations of Culicidae and Other Aquatic Invertebrates as Assessed in In Situ Microcosms (2000)
    Springer
    Archives of environmental contamination and toxicology 39 (2000), S. 329-336 
    Details
    ISSN: 1432-0703
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik , Medizin
    Notizen: Abstract Microcosm trials were conducted with the botanical insecticide Margosan-O® to assess the potential hazards of the product to aquatic organisms. Laboratory chronic bioassays with water from the treated microcosms were conducted to provide an estimate of the residual effect of Margosan-O. Results from chronic tests showed Margosan-O toxicity to be greater in the laboratory exposures than in situ with Culicidae larvae exposed to the same concentrations. Residue analyses of the active ingredient, azadirachtin, determined that it had a half-life of 36 to 48 h in water exposed to natural sunlight. Two applications of Margosan-O at the recommended application rate for pests did not harm aquatic invertebrates that are categorized as planktonic and filter feeding (Culex sp. and Daphnia sp.). However, the benthic invertebrate (Chironomus riparius) was affected by multiple applications of neem. These results show that the use of Margosan-O and possibly other neem extracts in or near aquatic environments could lead to disturbances in benthic populations and may cause decreases in numbers of organisms that are important in food web and nutrient cycling processes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s002440010112
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  • 9
    Digitale Medien
    Digitale Medien
    Short-term exposure of zooplankton to the synthetic pyrethroid, fenvalerate, and its effects on rates of filtration and assimilation of the alga,Chlamydomonas reinhardii (1987)
    Springer
    Archives of environmental contamination and toxicology 16 (1987), S. 423-432 
    Details
    ISSN: 1432-0703
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik , Medizin
    Notizen: Abstract In acute tests of toxicity, two cladocerans,Daphnia galeata mendotae andCeriodaphnia lacustris, and the calanoid,Diaptomus oregonensis, were more sensitive to fenvalerate thanDaphnia magna, the organism used in standard laboratory bioassays. The 48-hr EC50s for each species/stage in order of increasing sensitivity were adultD. magna — 2.52 μg/L;D. magna (≤48-hr old) — 0.83 μg/L; adultD. galeata mendotae — 0.29 μg/L; adultC. lacustris — 0.21 μg/L;D. galeata mendotae (≤48-hr old) — 0.16 μg/L; adultDiaptomus oregonensis — −0.12 μg/L. No toxicity was observed when these organisms were exposed to a range of concentrations of the emulsifiable concentrate without fenvalerate (the EC blank). Rates of filtration of the14C-labelled alga,Chlamydomonas reinhardii byD. galeata mendotae, C. lacustris andD. oregonensis were decreased significantly at sublethal concentrations of fenvalerate after only 24-hr exposure.Ceriodaphnia lacustris showed the greatest sensitivity with rates of filtration significantly decreased at 0.01 μg fenvalerate/ L. Concentrations of fenvalerate ≥0.05 μg/L resulted in decreased rates of filtration byD. galeata mendotae. A concentration of 0.10 μg fenvalerate/ L caused rates of filtration to increase inD. oregonensis. whereas 0.05 and 0.5 μg/L resulted in a decrease in these rates. Rates of assimilation of algae byD. galeata mendotae, C. lacustris andD. oregonensis exposed to similar concentrations of fenvalerate were decreased at concentrations ≥0.05 μg fenvalerate/L. Changes in rates of assimilation were not as sensitive a parameter of toxicity as changes in rates of filtration. The EC blank had no significant effects on rates of filtration or assimilation for all three species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01055263
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  • 10
    Digitale Medien
    Digitale Medien
    Acute toxicity of pure pentachlorophenol and a technical formulation to three species ofDaphnia (1991)
    Springer
    Archives of environmental contamination and toxicology 20 (1991), S. 73-80 
    Details
    ISSN: 1432-0703
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Energietechnik , Medizin
    Notizen: Abstract The acute toxicity of a technical formulation of pentachlorophenol (PCP) and pure pentachlorophenol to three age classes ofDaphnia magna, and adultD. pulex andD. galeata mendotae was determined by static toxicity tests. The influence of a number of factors on toxicity of PCP was also examined. The 48-hr LC50 estimates for adult daphnids of the three species exposed to pure PCP were 1.78, 4.59 and 0.51 mg/L, respectively, while those for the technical formulation were 2.57, 3.66 and 0.33 mg/L, respectively. There was little difference in toxicity between the technical and pure PCP; however, toxicity of both forms of PCP was influenced by duration of exposure, age (and/or size) and species of test organism and pH of the test solution. Pentachlorophenol caused a toxic response over a very narrow range of concentrations, with the greatest response occurring immediately between 0 and 24 hr. Pure PCP was equally toxic to all age classes ofD. magna but susceptibility to technical PCP decreased with maturation.D. g. mendotae was ten times more sensitive thanD. pulex to PCP. Pure PCP was significantly more toxic toD. magna at pH 5.5 than 7.0 with mean 48-hr LC50 values of 0.082 and 1.78 mg PCP/L, respectively. At 12°C, the toxicity of both forms of PCP toD. g. mendotae andD. pulex did not differ significantly from that at 20°C; however, technical PCP was significantly more toxic toD. magna at 12°C for an exposure duration of 48 hr. There was no effect of test container size (100, 250, 600 and 1,000 mL) on the toxicity of PCP toD. magna at 20°C with the lower pH of 5.5, suggesting that adsorption to glassware was not a factor in availability of PCP to test organisms. Beaker size had no effect on the toxicity of PCP toD. pulex at 20°C with test solutions having a pH of 7.0-8.0.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01065331
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