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  • 1
    Electronic Resource
    Electronic Resource
    Operation of contractile vacuoles in the euryhaline green flagellate Chlamydomonas pulsatilla (Chlorophyceae) as a function of salinity (1989)
    Springer
    Marine biology 100 (1989), S. 373-379 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chlamydomonas pulsatilla Wollenweber, a euryhaline, marine flagellate (isolated from rockpool at St. Andrew's, New Brunswick, Canada in 1980 by J. A. Hellebust), shows decreasing rates of activity of its four contractile vacuoles in the salinity range of 0 to 15% artificial seawater (ASW). Electron microscopy shows that the contractile vacuole complex persists as a spongiome (collection of small vesicles or tubules) in cells grown at salinities above the range for operation of contractile vacuoles. From calculations of rates of water expulsion, based on size and frequency of contraction of individual vacuoles determined by light microscopy, the time necessary to empty one cell volume increased from ca 20 min at 1% ASW to ca 600 min at 15% ASW. Analysis of inorganic and organic solute contents of cells grown at 1 and 5% ASW allowed the calculation of internal osmotic pressures. Estimates of hydraulic conductivities based on rates of water expulsion via contractile vacuoles and differences in internal and external osmotic pressures resulted in values ranging from 1.1 to 1.4×10-14 m s-1 Pa-1 for individual cells. Growth experiments at low photon flux densities over a salinity range of 1 to 15% ASW, over which contractile vacuole activity varied by a factor of 30, showed little difference in growth rates. This indicates that the cost for operation of contractile vacuoles must be very low. The secretion of large molecular weight organic substances does not appear to be associated with the functioning of contractile vacuoles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391153
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of methionine sulfoximine on growth and nitrogen assimilation of the marine microalga Chlorella autotrophica (1985)
    Springer
    Marine biology 86 (1985), S. 85-91 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chlorella autotrophica Shihira and Krauss (clone 580), a euryhaline microalga from the marine coastal environment is subject to large fluctuations in external salinity and nitrogen supply. The alga exhibits maximum growth at salinities lower than 100% ASW (artificial seawater). Cells divide faster and show higher cell yields when the supply of either NH 4 + or NO 3 - is increased above 0.2 mM. Cells growing on NH 4 + show high levels of NADPH-glutamate dehydrogenase (GDH) activity, and the levels of glutamine synthetase (GS) are decreased to very low levels under these conditions. Methionine sulfoximine (MSX), an inhibitor of GS, has little effect on cell division and nitrogen assimilation of cells growing on NH 4 + . Cells growing on NO 3 - , however, show marked inhibition (65%) in nitrogen assimilation in the presence of 5 mM MSX. This MSX concentration also causes growth retardation and a progressive decrease in cell protein and nitrogen content. GS is almost completely inhibited by 5 mM MSX in both NH 4 + and NO 3 - -grown cells. Cells growing on NH 4 + maintain high levels of NADPH-GDH activity in the presence of MSX. NADPH-GDH activity in MSX-treated NO 3 - -grown cells increases, and, in the presence of 5 mM MSX, reaches 40% of the level found in NH 4 + -grown cells. These results are consistent with NADPH-GDH providing an alternate pathway for NH 4 + assimilation by this marine Chlorella species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392582
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  • 3
    Electronic Resource
    Electronic Resource
    Osmoregulation in the euryhaline flagellate Brachiomonas submarina (Chlorophyceae) (1985)
    Springer
    Marine biology 87 (1985), S. 245-250 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Brachiomonas submarina Bohlin (Chlorophyceae), a euryhaline marine flagellate, can osmoregulate over a wide range of external salinity. The alga exhibits maximum water content at 100% artificial seawater (ASW), and shows only a small water loss (〈15%) when salinity is increased to 300% ASW. The non-aqueous volume of the cells is increased at salinities higher than 100% ASW. This is partially attributable to the accumulation of glycerol. Glycerol is the major osmoregulatory organic solute in this flagellate. The alga also shows an accumulation of amino acids in response to increased salinity. The contribution of glycerol and amino acids to intracellular osmolarity is only 9% at 10% ASW, but accounts for 49% at 300% ASW. The remainder of the osmotic balance is due to uptake and accumulation of inorganic ions, particularly sodium, potassium and chloride.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00397801
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  • 4
    Electronic Resource
    Electronic Resource
    Parasites and predators of pyrrhocoroidea [Hemiptera], and possible control of cotton stainers byPhonoctonus spp. [Themiptera: Reduviidae]] (1987)
    Springer
    BioControl 32 (1987), S. 269-275 
    Details
    ISSN: 1573-8248
    Keywords: Pyrrhocoridae ; Largidae ; cotton insects ; mimicry ; aposematicism ; Pyrrhocoridae ; Largidae ; insectes du coton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Les parasites et prédateurs de la super famille desPyrrhocoroidea ont été inventoriés d'après la bibliographie et leurs relations avec leurs hôtes sont discutées. L'impact des punaises prédatrices,Phonoctonus spp., sur les populations de punaises du coton (Dysdercus spp.) est évalué; un élevage et un programme de lâchers sont recommandés.
    Notes: Abstract Parasites and predators of the hemipteran superfamily Pyrrhocoroidea are compiled from the literature, and their relationship with their hosts discussed. The impact of the predacious bugs,Phonoctonus spp., on populations of cotton stainers (Dysdercus spp.) is evaluated; a rearing and release program is recommended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02373250
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  • 5
    Electronic Resource
    Electronic Resource
    On the electrodeposition and characterization of niobium from fused fluoride electrolytes (1987)
    Springer
    Journal of applied electrochemistry 17 (1987), S. 253-260 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The electrodeposition of niobium from a binary electrolyte consisting of KF and NaF was characterized and compared with that from the ternary electrolyte of LiF, NaF and KF. The deposition experiments were conducted at current densities between 5 and 35 mA cm−2 and electrolyte temperatures between 725 and 800°C. DTA measurements indicated the melting points to be 450 and 710°C for the ternary and binary electrolytes with added K2NbF7; however, it was necessary to operate both electrolytes above 725°C to obtain dense coherent deposits. Coating morphology was described by optical and scanning electron microscopy studies, while coating structure and properties were characterized by X-ray diffraction analysis. In particular, a series of diffraction measurements were reported to describe the changes in the microstructure of the deposited material as a function of the preparation conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01023291
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  • 6
    Electronic Resource
    Electronic Resource
    Design of liposomes to improve delivery of amphotericin-B in the treatment of aspergillosis (1989)
    Springer
    Molecular and cellular biochemistry 91 (1989), S. 85-90 
    Details
    ISSN: 1573-4919
    Keywords: liposome ; aspergillosis ; mannose ; amphotericin-B
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The efficacy and toxicity of free and liposome intercalated amphotericin-B (Amp-B) in controlling Aspergillosis, caused byAspergillus fumigatus in BALB/c mice were studied. Liposomal Amp-B had higher LD50 (8.1 mg/kg) as compared to that of the free drug (1.2 mg/kg). An improvement in the therapeutic index of the drug was observed with liposomal formulation of the drug. We also focussed on the effect of lipid composition and surface sugar in modulating the therapeutic potency of Amp-B. The most effective liposomal preparation was composed of egg phosphatidylcholine (EPC) : L-α-phosphatidylethanolamine, dipalmitoyl (DPPE): cholesterol (Chol) in the molar ratio of 6:1:3. Amp-B intercalated into mannose grafted liposomes (LD50 = 9.3 mg/kg) was more effective as compared to the other formulation tested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228082
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  • 7
    Electronic Resource
    Electronic Resource
    Iodine determination in water samples from endemic goitrous areas using MAA (1988)
    Springer
    Journal of radioanalytical and nuclear chemistry 120 (1988), S. 89-95 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A rapid and simple method for the determination of iodine from water has been described which is based on preconcentration of iodine with 0.1M solution of 4-(5-nonylpyridine) in benzene or carbon tetrachloride from 1–2M HNO3 followed by neutron irradiation and gamma-ray activity measurements. A clinical survey of endemic goitrous area has also been made to find a possible correlation between the endemic goiter and iodine deficiency in water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02037854
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