ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Drosophila
  • calcium
  • Springer  (629)
  • Alfred Wegener Institute for Polar and Marine Research & German Society of Polar Research
  • 2005-2009
  • 1995-1999  (332)
  • 1985-1989  (297)
  • 1950-1954
Collection
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 175-181 
    ISSN: 1570-7458
    Keywords: Olfactory response ; Drosophila ; menthol ; bioassay ; trap assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A modification of the trap assay (Woodard et al., 1989) was used to evaluate the response of Drosophila melanogaster (Meigen) to food media containing menthol. Dose-response curves for flies to mentholic foods were produced for flies that had been pre-exposed to menthol, during development and adult life, and flies that had not been exposed to menthol before the assay. Mentholic food media were less attractive to Drosophila than plain food medium. Rearing flies on a medium containing menthol reduced their aversion to some concentrations of menthol. The rearing effect was not simply due to lowered general activity levels resulting from developing in a medium containing menthol. There was a threshold concentration of menthol in the rearing medium below which we found no induced behavioural change.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1573-0867
    Keywords: calcium ; compost ; irradiation ; magnesium ; manure ; sewage sludge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Application of organic waste influences crop uptake of Ca and Mg and soil extractability, depending on the nature of the crop and the waste. Four organic wastes: (i) digested sewage sludge (DSS), (ii) irradiated sludge (DISS), (iii) composted sludge (DICSS), and (iv) composted livestock manure (CLM) were applied for two years at rates of 10, 20, 30, and 40 Mg solid ha-1 year-1. Fertilizers N and K were applied to the control treatment (CT), as well as to the waste treatments to supplement crop growth across all treatments, so that these nutrients were not treatment variables. Calcium and Mg concentrations in the tissue of lettuce, bean pods and petunias in 1990 and two cuts of lettuce in 1991, and the CH3COONH4-extractable soil Ca and Mg were determined. Concentration of Ca and Mg in bean pods did not change to the waste application. Calcium concentration in bean pods was less than half of that in other crops. Magnesium concentration in bean pods and petunias was same, but was much lower than in lettuce. Application of DSS, in general, increased Ca concentration in the crops more than did other wastes. The extractable soil Ca was positively correlated with Ca applied with DISS (r=0.453, P〈0.05). Although only a limited amount of Ca was supplied with CLM at the rate of 10 Mg solid ha-1(40 kg Ca ha-1), Ca concentration in petunias increased significantly, then, decreased with increased Ca application (r=0.453, P〈0.05). A similar pattern with CLM was found in the extractable soil Ca. The waste application from all the sources had no influence on crop Mg concentration in 1990, possibly due to low Mg concentration in the wastes. While continuously applied DSS and DISS in 1991 linearly increased Mg concentration in both cuts of lettuce (r=0.867, P〈0.01; r=0.670, P〈0.01 and r=0.671, P〈0.01; r=0.665, P〈0.01 for first cut and second cut of lettuce with DSS and DISS application respectively), application of CLM decreased Mg concentration in first cut lettuce. The patterns of extractable soil Mg were opposite to crop Mg concentration, as the extractable soil Mg linearly increased with CLM, and decreased with the high rate of DSS application. The ability of wastes to supply N was an important factor influencing crop Σ cations (K, Ca and Mg) uptake.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-041X
    Keywords: Key words bHLH genes ; Drosophila ; Embryogenesis ; Enhancer of split ; Notch pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  E(spl) bHLH genes are targets of the Notch pathway: they are transcriptionally activated in response to the Notch signal. Yet, during imaginal development, additional regulatory factors appear to modulate transcription resulting in different expression patterns. During early embryogenesis all E(spl) bHLH genes are expressed in roughly the same domain, namely the neurogenic ectoderm. Within this region these seven genes show a highly dynamic, yet distinct transcriptional activity. Our analysis further detected tissue specific expression of some E(spl) genes at later embryonic stages. Prominent differences were observed in the dorsolateral and procephalic neuroectodermal regions as well as in the mesoderm. These observations indicate that other factors in addition to the Notch signal participate in the regulation of the individual E(spl) genes not only in imaginal tissues but also during neuroblast specification and other cell fate determination events in the embryo.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1432-041X
    Keywords: Key words Delta ; Notch ; Follicle cells ; Oogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  During Drosophila oogenesis the body axes are determined by signaling between the oocyte and the somatic follicle cells that surround the egg chamber. A key event in the establishment of oocyte anterior-posterior polarity is the differential patterning of the follicle cell epithelium along the anterior-posterior axis. Both the Notch and epithelial growth factor (EGF) receptor pathways are required for this patterning. To understand how these pathways act in the process we have analyzed markers for anterior and posterior follicle cells accompanying constitutive activation of the EGF receptor, loss of Notch function, and ectopic expression of Delta. We find that a constitutively active EGF receptor can induce posterior fate in anterior but not in lateral follicle cells, showing that the EGF receptor pathway can act only on predetermined terminal cells. Furthermore, Notch function is required at both termini for appropriate expression of anterior and posterior markers, while loss of both the EGF receptor and Notch pathways mimic the Notch loss-of-function phenotype. Ectopic expression of the Notch ligand, Delta, disturbs EGF receptor dependent posterior follicle cell differentiation and anterior-posterior polarity of the oocyte. Our data are consistent with a model in which the Notch pathway is required for early follicle cell differentiation at both termini, but is then repressed at the posterior for proper determination of the posterior follicle cells by the EGF receptor pathway.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-041X
    Keywords: Key words Synapse ; Drosophila ; Immunoglobulin superfamily ; Axonal transport ; Neurosecretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Hikaru genki (HIG) is a putative secreted protein of Drosophila that belongs to immunoglobulin and complement-binding protein superfamilies. Previous studies reported that, during pupal and adult stages, HIG protein is synthesized in subsets of neurons and appears to be secreted to the synaptic clefts of neuron-neuron synapses in the central nervous system (CNS). Here we report the analyses of distribution patterns of HIG protein at embryonic and larval stages. In embryos, HIG was mainly observed in subsets of neurons of the CNS that include pCC interneurons and RP5 motorneurons. At third instar larval stage, this protein was detected in a limited number of cells in the brain and ventral nerve cord. Among them are the motorneurons that extend their axons to make neuromuscular junctions on body wall muscle 8. Immunoelectron microscopy showed that these axonal processes as well as the neuromuscular terminals contain numerous vesicles with HIG staining, suggesting that HIG is in a pathway of secretion at this stage. Some neurosecretory cells were also found to express this protein. These data suggest that HIG functions in the nervous system through most developmental stages and may serve as a secreted signalling molecule to modulate the property of synapses or the physiology of the postsynaptic cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 209 (1999), S. 218-225 
    ISSN: 1432-041X
    Keywords: Key words α-catenin ; Drosophila ; Green fluorescent protein (GFP) ; Adherens junction ; Epithelial morphogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Cell-cell adherens junctions (AJs), comprised of the cadherin-catenin adhesion system, contribute to cell shape changes and cell movements in epithelial morphogenesis. However, little is known about the dynamic features of AJs in cells of the developing embryo. In this study, we constructed Dα-catenin fused with a green fluorescent protein (Dα-catenin-GFP), and found that it targeted apically located AJ-based contacts but not other lateral contacts in epithelial cells of living Drosophila embryos. Using time-lapse fluorescence microscopy, we examined the dynamic performance of AJs containing Dα-catenin-GFP in epithelial morphogenetic movements. In the ventral ectoderm of stage 11 embryos, concentration and deconcentration of Dα-catenin-GFP occurred concomitantly with changes in length of AJ contacts. In the lateral ectoderm of embryos at the same stage, dynamic behaviour of AJs was concerted with division and delamination of sensory organ precursor (SOP) cells. Moreover, changes in patterns of AJ networks during tracheal extension could be followed. Finally, we utilized Dα-catenin-GFP to precisely observe the defects in tracheal fusion in shotgun mutants. Thus, the Dα-catenin-GFP fusion protein is a helpful tool to simultaneously observe morphogenetic movements and AJ dynamics at high spatio-temporal resolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1432-041X
    Keywords: Key words Deformed ; Drosophila ; Embryogenesis ; Tribolium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We have analyzed the Tribolium castaneum ortholog of the Drosophila homeotic gene Deformed (Dfd) and determined its expression pattern during embryogenesis in this beetle. Tc Deformed (Tc Dfd) is expressed in the blastoderm and the condensing germ rudiment in a region that gives rise to gnathal segments. During germ band extension Tc Dfd is expressed in the mandibular and maxillary segments, their appendages, and the dorsal ridge. Comparison of insect Dfd protein sequences reveals several highly conserved regions. To determine whether common molecular features reflect conserved regulatory functions we used the Gal4 system to express the Tribolium protein in Drosophila embryos. When Tc Dfd is expressed throughout embryonic ectoderm under the control of P69B, the beetle protein autoregulates the endogenous Dfd gene. In addition, the Drosophila proboscipedia gene (a normal target of Dfd) is ectopically activated in the antennal and thoracic segments. We also compared the ability of the beetle and fly proteins to rescue defects in Dfd – mutants by expressing each throughout the embryonic during embryogenesis. Both proteins rescued Dfd – defects to the same extent in that they each restore the development of mouth hooks and cirri, as well as cause gain-of-function abnormalities of posterior mouth parts. As before, pb was ectopically activated in the antennal segment. This is the first demonstration of the ability of a heterologous homeotic selector protein to directly regulate a target gene independent of an endogenous Drosophila autoregulatory loop.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 190 (1999), S. 185-190 
    ISSN: 1573-4919
    Keywords: calcium ; calcium wave ; calcium oscillation ; inositol 1,4,5-trisphosphate receptor ; ryanodine receptor ; excitation-concentration coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract After the seminal work of Ebashi and coworkers which established the essential role of the intracellular Ca2+ concentration ([Ca2+]i) in the regulation of skeletal muscle contraction, we have witnessed an explosive elongation of the list of cell functions that are controlled by the [Ca2+]i. In numerous instances, release of intracellular Ca2+ stores plays important roles in Ca2+ signalling which displays significant variation in spatio-temporal pattern. There are two families of Ca2+ release channels, ryanodine receptors and inositol 1,4,5-trisphosphate (IP3) receptors. These Ca2+ release channels are structurally and functionally similar. In particular, the activity of both types of channels is regulated by the [Ca2+]i. The [Ca2+]i dependence of the Ca2+ release channel activity provides both types of channels with properties of a Ca2+ signal amplifier. This function of the ryanodine receptor is important in striated muscle excitation-contraction coupling, whereas that of the IP3 receptor seems to be the basis of the generation of Ca2+ waves. Thus the wide variety of Ca2+ signalling patterns seem to be critically dependent on the [Ca2+]i dependence of the Ca2+ release channels.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 190 (1999), S. 39-45 
    ISSN: 1573-4919
    Keywords: microcalorimetry ; calcium ; troponin C ; calmodulin ; parvalbumin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Results of microcalorimetric titrations of calcium-binding proteins with calcium or magnesium have been reviewed and evaluated. Results were analyzed mostly in terms of heat capacity changes, which is most closely related to the structural changes of the molecule on metal binding. Two high-affinity sites of rabbit skeletal troponin C are distinguishable in terms of their affinity to calcium and associated enthalpy changes. Heat capacity changes on calcium binding to one of the two high-affinity sites is negative and is in the range ascribed to the ligand binding. In contrast, that to the other of the high-affinity sites is large and positive, indicating that a substantial area of hydrophobic groups become exposed to the solvent. In frog skeletal troponin C, the anomalous positive heat capacity changes occur in one of the low-affinity calcium-specific sites, so that this may be involved in the regulation of contraction. Unlike skeletal troponin C, both of the two high-affinity sites of cardiac troponin C show negative heat capacity changes. In calmodulin, heat capacity changes are positive but small, indicating that calcium binding may induce clustering of the hydrophobic residues on the surface of the molecule. In parvalbumins, heat capacity changes are negative, characteristic of most ligand binding.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1573-4919
    Keywords: CGRP-1 receptor ; HEK-293 cells ; calcium ; cholera toxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse biological properties including potent vasodilating activity. Recently, we reported the cloning of complementary DNAs (cDNAs) encoding the human and porcine CGRP receptors which share significant amino acid sequence homology with the human calcitonin receptor, a member of the recently described novel subfamily of G-protein-coupled 7TM receptors. Activation of this family of receptors has been shown to result in an increase in intracellular cAMP accumulation and calcium release. In this study, we demonstrate that HEK-293 cells expressing recombinant CGRP receptors (HEK-293HR or PR) respond to CGRP with increased intracellular calcium release (EC50 = 1.6 nM) in addition to the activation of adenylyl cyclase (EC50 = 1.4 nM). The effect of CGRP on adenylyl cyclase activation and calcium release was inhibited by CGRP (8-37), a CGRP receptor antagonist. Both effects were mediated by cholera toxin-sensitive G-proteins, but these two signal transduction pathways were independent of each other. While cholera toxin pretreatment of HEK-293PR cells resulted in permanent activation of adenylyl cyclase, the same pretreatment resulted in an inhibition of CGRP-mediated [Ca2+]i release. Pertussis toxin was without effect on CGRP-mediated responses. In addition, CGRP-mediated calcium release appears to be due to release from a thapsigargin-sensitive intracellular calcium pool. These results show that the recombinant human as well as porcine CGRP receptor can independently increase both cAMP production and intracellular calcium release when stably expressed in the HEK-293 cell line.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 194 (1999), S. 159-164 
    ISSN: 1573-4919
    Keywords: free radicals ; ischemia-reperfusion ; sarcoplasmic reticulum ; Ca2+-Mg2+-ATPase ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Reactive oxygen species (ROS, free radicals) produced during cardiac ischemia and reperfusion can damage the contractile functions of arteries. The sarcoplasmic reticulum (SR) Ca2+ pump in coronary artery smooth muscle is very sensitive to ROS. Here we show that contractions of de-endothelialized rings from porcine left coronary artery produced by the hormone Angiotensin II and by the SR Ca2+ pump inhibitors cyclopiazonic acid and thapsigargin correlate negatively with the tissue weight. In contrast, the contractions due to membrane depolarization by high KCl correlate positively. Peroxide also produces a small contraction which correlates negatively with the tissue weight. When artery rings are treated with peroxide and washed, their ability to contract with Angiotensin II, cyclopiazonic acid and thapsigargin decreases. Thus, the SR Ca2+ pump may play a more important role in the contractility of the smaller segments of the coronary artery than in the larger segments. These results are consistent with the hypothesis that ROS which damage the SR Ca2+ pump affect the contractile function of the distal segments more adversely than of the proximal segments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 194 (1999), S. 173-177 
    ISSN: 1573-4919
    Keywords: calcium ; ATPase ; central nervous system ; phencyclidine ; inhibition ; in vitro ; in vivo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Phencyclidine (PCP) is a potent psychotomimetic drug of abuse and has profound effect on the functioning of the central nervous system (CNS). Many of the CNS functions are known to be mediated by calcium (Ca2+). In the present study we have investigated the effects of PCP on Ca2+ ATPase activity in rat brain both in vitro and in vivo. For in vitro studies, synaptic membrane fractions prepared from normal rat brain were incubated with PCP at different concentrations (25-100 μM) before the addition of substrate. For n vivo studies, rats were treated with a single moderate dose of PCP (10 mg/kg, IP) and animals were sacrificed at 1,2, 6 and 12 h after treatment. Ca2+ ATPase activity in synaptic membrane fractions was assayed by estimation of inorganic phosphate. PCP inhibited the Ca2+ ATPase in vitro in a concentration dependent manner with significant effect at 50 and 100 μM. A significant time-dependent reduction of the Ca2+ ATPase activity was evident in vivo. As early as 2 h after the treatment of rats with PCP the ATPase activity was significantly reduced. The reduction of Ca2+ ATPase observed even at 12 h after treatment suggesting a prolonged presence of the drug in the brain tissue. Further, kinetic studies in vitro indicated PCP to be a competitive inhibitor of Ca2+ ATPase with respect to the substrate, ATP. The present findings indicate that PCP inhibits synaptic membrane Ca2+ ATPase thus altering cellular Ca2+ homeostasis in CNS which may partially explain the pharmacological effects of the drug and/or its neurotoxicity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    ISSN: 1573-4919
    Keywords: ultraviolet radiation ; oxidative stress ; calcium ; phospholipase A2 ; thrombin ; V79 fibroblast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract V79 fibroblasts were treated with ultraviolet (UV) C radiation alone as well as in conjunction with chronic oxidative stress. The effects of these treatments on calcium signaling were observed at 30 min post-irradiation. In the absence of extracellular calcium, thrombin released calcium from internal stores of UVC-irradiated V79 fibroblasts even after exposure to neomycin. In neomycin-treated control and chronic oxidative stress cells, no calcium release by thrombin was observed after chelation of external calcium. Calcium release by thrombin from internal stores of UV-irradiated and neomycin-treated cells was completely abolished by pretreatment with N-acetyl cysteine and dexamethasone. Cellular total soluble thiol content which is a good indicator of cellular reduced glutathione (GSH) level was significantly elevated 30 min after ultraviolet radiation, indicating an adaptive response after oxidative stress. Chronic oxidative stress alone resulted in a much smaller increase in GSH but chronic oxidative stress in conjunction with UVC produced a very prominent elevation in GSH levels. Our data suggest that thrombin can cause calcium release from internal stores of ultraviolet-irradiated fibroblasts which is independent of phosphatidylinositol bisphosphate hydrolysis and is directly related to the level of oxidative stress. Involvement of phopholipase A2 and a role for its products as possible mediators of calcium release from intracellular stores, is strongly indicated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 197 (1999), S. 25-29 
    ISSN: 1573-4919
    Keywords: regucalcin ; anti-regucalcin antibody ; protein phosphatase ; calcium ; rat liver cytosol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of anti-regucalcin monoclonal antibody on neutral phoshatase activity in rat liver cytosol was investigated. Phosphotyrosine, phosphoserine, and phosphothreonine were used as the substrate toward phosphatase asssy. Liver cytosolic phosphatase activity with three phosphoaminoacids was significantly increased in the presence of anti-regucalcin antibody (100 and 200 ng/ml) in the enzyme reaction mixture with calcium chloride (0.1 mM) or EGTA (1.0 mM). The effect of anti-regucalcin antibody was completely abolished in the presence of exogenous regucalcin (1.0 μM), indicating the involvement of endogenous regucalcin. The anti-regucalcin anti body- increased phosphatase activity was not significantly altered in the presence of trifluoperazine (20 μM), an antagonist of calmodulin, or akadaic acid (10 μM), an inhibitor of protein phosphatase, although these inihibitors caused a slight decrease in liver cytosolic phosphatase activity. The effect of endogenous regucalcin might be not related to calmodulin, and it was insensitive to okadaic acid. The present findings suggest that endogenous regucalcin is involved in the regulation of protein phasphatase in rat liver cytoplasm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    ISSN: 1573-4919
    Keywords: isolated cardiac mitochondria ; cyclosporin A ; calcium ; magnesium ; oxidative phosphorylation ; high energy phosphate production ; Krebs cycle intermediates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract This study was designed to determine the effect of calcium and ADP-Mg on the oxidative phosphorylation in isolated cardiac mitochondria. The influence of cyclosporin A was also evaluated. The mitochondria were extracted from rat ventricles. Their oxidative phosphorylations were determined in two respiration media with different free Ca2+ concentrations. Respiration was determined with palmitoylcarnitine and either ADP- or ADP-Mg. With elevated free Ca2+concentrations and ADP-Mg, the transition state III to state IV respiration did not occurred. The ADP:O ratio was reduced. The phenomenon was not observed in the other experimental conditions (low free Ca2+ concentration with either ADP- or ADP-Mg or elevated free Ca2+ concentration with ADP-). Uncoupling was allied with a constant AMP production, which maintained an elevated ADP level in the respiration medium and prevented the return to state IV respiration. It was also observed in a respiration medium devoid of free Ca2+ when the mitochondria were pre-loaded with Ca2+. Uncoupling was inhibited by cyclosporin A. Furthermore, the Krebs cycle intermediates released from14C-palmitoylcarnitine oxidation revealed that succinate was increased by elevated free Ca2+ and ADP-Mg. Succinate is a FAD-linked substrate with low respiration efficiency. Its accumulation could account for the decreased ADP:O ratio. The Ca2+- and ADP-Mg-induced uncoupling might be partly responsible for the mechanical abnormalities observed during low-flow ischemia. (Mol Cell Biochem 000: 000-000, 1999)
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    ISSN: 1573-4919
    Keywords: Salmonella typhimurium ; diarrhoea ; porins ; calcium ; protein kinase C ; free radicals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Attachment of Salmonella typhimurium to epithelial surfaces elicit significant alterations in different cell signalling events which lead to the development of disease. The present investigation was conducted to evaluate the effect of immunization of rats with porins, on gut physiologic markers following challenge with S. typhimurium. Male albino Wistar rats were immunized with purified porins and challenged by intragastric infection with S. typhimurium. Electrolyte transport, levels of different second messengers and inflammatory mediators were studied. A net absorption of transepithelial fluxes of Na+ and Cl- in immunized-challenged group and secretion in infected group was found. Ca2+ and 3-O-methyl-D-glucose fluxes did not show any change. Significant increase in the levels of [Ca+]i, cAMP, membrane form of protein kinase C, prostaglandins, NADPH oxidase, Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, total oxygen free radicals, reactive nitrogen intermediates, citrulline and lipid peroxidation was found in the infected group. However, in the immunized-challenged group, the values of all the parameters were found to be almost the same as that of control as well as immunized groups. Na+, K+-ATPase and calmodulin levels were unaltered in all the groups of animals. The results of this study thus suggest that immunization of rats with purified Salmonella porins followed by subsequent challenge with the organism might be helpful for the prevention of multiple physiologic derangements in isolated ideal cells.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 201 (1999), S. 159-167 
    ISSN: 1573-4919
    Keywords: phospholipases A1, A2 and C ; Ureaplasma urealyticum ; calcium ; plasma membrane ; phospholipids ; pH ; detergents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The presence of endogenous phospholipase A (PL-A) activity of U. urealyticum hydrolyzing the acyl ester bond and phospholipase C (PL-C) activity hydrolyzing the phosphodiester bond is primarily localized in the membranes of ureaplasmas. Characterization of the membrane PL-A and PL-C activity in exponential growing cells of serovars 3, 4, and 8 was investigated. The pH optimum was about 8.5-9 for phospholipase A1 (PL-A1) in the three serovars. A more acidic pH optimum of 6 was observed for phospholipase A2 (PL-A2) enzymes in serovars 3 and 4. However, a very significant stimulation of PL-A2 activity in serovar 8 occurred around pH 7. The specific activity of PL-A2 was always 50-100 fold higher than PL-A1 activity in the pH range studied. Ca2+ ions only slightly stimulated PL-A1 activity in all 3 serovars. PL-A2 activity was stimulated about 6-fold from 0.5-0.8 mM Ca2+ ion concentrations for serovar 3 and 12-fold for serovar 8. Only lower concentrations (0.2-0.4 mM) of calcium stimulated PL-A2 activity in serovar 4. EDTA inhibition corresponded to Ca2+ stimulation for PL-A2 activity for serovars 3 and 8. A general stimulation of PL-A2 activity by diethyl ether was evident but the degree of stimulation varied with the serovar. Sodium deoxycholate enhanced PL-A activity of serovars 4 and 3, but partially inhibited that of serovar 8. PL-A activity in the three serovars were not significantly affected by p-hydroxymercuribenzoate, a marker of -SH groups in the enzyme. All 3 serovars were inactivated by heat. A broad pH optimum for PL-C activity was evident around 7-8. Diethyl ether enhanced PL-C activity of serovar 8. Sodium deoxycholate and heat were inhibitory to PL-C activity. The results demonstrate that the major characteristics of ureaplasma membrane bound PL-A and PL-C are basically similar to those of other mollicutes and bacteria. However, the major differences in the specific characteristics of specially PL-A1 and PL-A2 suggest that the ureaplasma phospholipases are unique enzymes different from the phospholipases of bacteria. Both the PL-A and PL-C enzymes function over the broad range at which ureaplasma can grow, pH 5-9 essential for survival. The ureaplasma PL-As are also markedly different from one serovar to another. This variation in specific activity could contribute significantly to differences in virulence among serovars in specific host milieus. There is significant variation from acidic pH of the vagina and alveolar surface of the lung to a more neutral pH of the endometrium and placenta. There are marked differences in calcium concentrations under specific circumstances in various host tissues. Thus the differences in specific activity among the phospholipases of the serovars of U. urealyticum may be of physiological importance in interactions with host tissues and pathogenesis of disease.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Molecular biology reports 26 (1999), S. 103-111 
    ISSN: 1573-4978
    Keywords: arthropod ; crustacean ; Drosophila ; insect ; lobster ; multicatalyic proteinase ; proteasome ; ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recent work on structural/functional relationships in arthropod proteasomes is reviewed. Taking advantage of our ability to induce a stable, proteolytically-active conformation of the lobster proteasome, the structures of basal and heat-activated complexes were probed with exogenous proteases. Increased sensitivity to chymotrypsin and trypsin showed that heat activation induced a more ‘open’ conformation, allowing entry of large substrates into the catalytic chamber. In Drosophila, the effects of two developmental mutant alleles (DTS-7 and DTS-5) encoding proteasome subunits (Z and C5, respectively) on the subunit composition and catalytic activities of the enzyme were examined. Both qualitative and quantitative differences in compositions between wild-type (+/+) and heterozygotes (+/DTS) indicated that incorporation of mutant subunits alters post-translational modifications of the complex. Catalytic activities, however, were similar, which suggests that the developmental defect involves other proteasome properties, such as intracellular localization and/or interactions with endogenous regulators. A hypothetical model in which DTS subunits act as poison subunits is presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Molecular biology reports 26 (1999), S. 147-157 
    ISSN: 1573-4978
    Keywords: Drosophila ; jun ; fos ; AP-1 ; transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mammalian proto-oncogenes c-jun and c-fos are situated at the end of multiple signal transduction pathways and activation of their products Jun and Fos, components of the transcription factor AP-1, are able to regulate gene transcription in response to extracellular stimuli. Djun and Dfos, the products of the Drosophila proto-oncongenes Djun and Dfos, are similar in size and sequence to their mammalian counterparts c-Jun and c-Fos and are related to their mammalian counterparts by their antigenic properties. However, very little is known about how they are regulated through signal transduction pathways. This paper has investigated the response of their mRNA abundance levels to three signal transduction pathways in Drosophila cultured cells. Various agonists and anagonists that stimulate and inhibit specific enzymes in the pathways have been tested. The results suggest that Djun and Dfos mRNA are continuously expressed and their abundance levels are transiently regulated by multiple signaling pathways, the peak response coming at 1–2 hours after perturbation. Dfos is more highly regulated than Djun which is only modulated. The receptor tyrosine kinase pathways positively regulate Dfos and Djun. The cAMP-mediated pathway positively regulates Dfos but negatively regulates Djun. The protein kinase C-activated pathway does not affect Djun whereas it negatively regulates Dfos.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    ISSN: 1617-4623
    Keywords: Key words Molybdenum cofactor biosynthesis ; Drosophila ; cinnamon ; cnx1 ; GEPHYRIN
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Molybdoenzymes are involved in a variety of essential pathways including nitrate assimilation, sulfur and/or purine metabolism and abscisic acid biosynthesis. Most organisms produce several such enzymes requiring a molybdopterin cofactor for catalytic function. Mutations that result in a lack of the molybdopterin cofactor display a pleiotropic loss of molybdoenzyme activities, and this phenotype has been used to identify genes involved in cofactor biosynthesis or utilization. Although several cofactor genes have been analyzed in prokaryotes, much less is known concerning eukaryotic molybdenum cofactor (MoCF) genes. This work is focused on the Drosophila MoCF gene cinnamon (cin) which encodes a multidomain protein, CIN, that shows significant similarity to three proteins encoded by separate prokaryotic MoCF genes. These domains are also present in the product of cnx1, an Arabidopsis MoCF gene, and in GEPHYRIN, a rat protein thought to organize the glycine receptor, GlyR, within the postsynaptic membrane. Since this apparent consolidation of separate prokaryotic genes into a single eukaryotic gene is a feature of other conserved metabolic pathways, we wished to determine whether the protein's function is also conserved. This report shows that the plant gene cnx1 can rescue both enzymatic and physiological defects of Drosophila carrying cin mutations, indicating that the two genes serve similar or identical functions. In addition, we have investigated the relationship between CINNAMON and GEPHYRIN, using immunohistochemical methods to localize the CIN protein in Drosophila embryos. Most of the CIN protein, like GEPHYRIN in the rat CNS, is localized to the cell borders and shows a tissue-specific pattern of expression. In a parallel study, antibody to GEPHYRIN revealed the same tissue-specific expression pattern in fly embryos. Both antibodies show altered staining patterns in cin mutants. Taken together, these results suggest that GEPHYRIN may also carry out a MoCF-related function.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 262 (1999), S. 618-622 
    ISSN: 1617-4623
    Keywords: Key words Telomeric retrotransposons ; HeT-A elements ; Centric heterochromatin ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have isolated two yeast artificial chromosome (YAC) clones from Drosophila melanogaster that contain a small amount of dodeca satellite (a satellite DNA located in the centromeric region of chromosome 3) and sequences homologous to the telomeric retrotransposon HeT-A. Using these YACs as probes for fluorescence in situ hybridization to mitotic chromosomes, we have localized these HeT-A elements to the centric heterochromatin of chromosome 3, at region h55. The possible origin of these telomeric elements in a centromeric position is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    International journal of salt lake research 8 (1999), S. 99-112 
    ISSN: 1573-8590
    Keywords: demineralization ; saline lake ; Central Asia ; Lake Balkhash ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Lake Balkhash is one of the many closed lakes in Central Asia. Mechanisms of demineralization in Lake Balkhash were considered from results of surveys undertaken on the lake and along the Ili River. Electrical conductivity (EC) values at the eastern coast in south-western Lake Balkhash were higher than those of the western coast. The Ili River enters at the south-western corner of the lake, so that EC values of this area are low. This water flows westwards. The distribution of Ca2+ concentrations showed that these were lower value in Lake Balkhash than along the Ili River, implying Ca2+ removal by the lake. Amongst suspended mineral matter in the lake occur calcite and dolomite. Thus, a possible mechanism of calcium removal is that it is removed as crystals of calcite or dolomite. SO 4 2− concentration within the lake has increased for the past 37 years. This may be caused by the discharge into the lake from the city of Balkhash of waste water from a copper smelter.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    International journal of salt lake research 8 (1999), S. 99-112 
    ISSN: 1573-8590
    Keywords: demineralization ; saline lake ; Central Asia ; Lake Balkhash ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geography
    Notes: Abstract Lake Balkhash is one of the many closed lakes in Central Asia. Mechanisms of demineralization in Lake Balkhash were considered from results of surveys undertaken on the lake and along the Ili River. Electrical conductivity (EC) values at the eastern coast in south-western Lake Balkhash were higher than those of the western coast. The Ili River enters at the south-western corner of the lake, so that EC values of this area are low. This water flows westwards. The distribution of Ca2+ concentrations showed that these were lower value in Lake Balkhash than along the Ili River, implying Ca2+ removal by the lake. Amongst suspended mineral matter in the lake occur calcite and dolomite. Thus, a possible mechanism of calcium removal is that it is removed as crystals of calcite or dolomite. SO 4 2− concentration within the lake has increased for the past 37 years. This may be caused by the discharge into the lake from the city of Balkhash of waste water from a copper smelter.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    ISSN: 1573-4935
    Keywords: Mitochondrial permeability transition ; acid pH ; protein sulfhydryl oxidation ; calcium ; reactive oxygen species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ca2+ and inorganic phosphate-induced mitochondrial swelling and membrane protein thiol oxidation, which are associated with mitochondrial permeability transition, are inhibited by progressively decreasing the incubation medium pH between 7.2 and 6.0. Nevertheless, the detection of mitochondrial H2O2 production under these conditions is increased. Permeability transition induced by phenylarsine oxide, which promotes membrane protein thiol cross-linkage in a process independent of Ca2+ or reactive oxygen species, is also strongly inhibited in acidic incubation media. In addition, we observed that the decreased protein thiol reactivity with phenylarsine oxide or phenylarsine oxide-induced swelling at pH 6.0 is reversed by diethyl pyrocarbonate, in a hydroxylamine-sensitive manner. These results provide evidence that the inhibition of mitrochondrial permeability transition observed at lower incubation medium pH is mediated by a decrease in membrane protein thiol reactivity, related to the protonation of protein histidyl residues.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Apoptosis 4 (1999), S. 239-243 
    ISSN: 1573-675X
    Keywords: Apoptosis ; cell survival ; differentiation ; Drosophila ; EGFR ; hid ; ras.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The Drosophila epidermal growth factor receptor (EGFR), functioning through the Ras/Raf/MAPK pathway, promotes cell proliferation and differentiation. Recent work has demonstrated that EGFR functions via the same Ras/Raf/MAPK pathway to promote cell survival. This review summarizes the role of EGFR in differentiation and survival during Drosophila eye development.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    ISSN: 1573-6857
    Keywords: P element ; repressor ; maternal effect ; Drosophila ; population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract As part of our effort to monitor changes in the clinal pattern of P element-associated traits in eastern Australian Drosophila melanogaster, we investigated the genomic P elements of 293 isofemale lines collected in the period 1991–1994 from 45 localities. P elements were present in many copies in all genomes examined, with full-size P and KP element size classes accounting for the large majority. SR elements were not present in at least 92% of the lines tested. South of about 26° south Latitude (°SLat), the ratio of KP to full-size P elements (KP/P ratio) increased, correlating weakly with the P-M phenotypes of the populations, from moderately P populations (26–29°SLat) to M populations (37–38°SLat) North of 26°SLat, in weak P populations, the KP/P ratio was higher than between 26 and 29°Slat. The KP/P ratio appears to be higher in the northern populations than it was when previous studies were done. Overall, a high KP/P ratio among lines correlated roughly with a lack of P activity, but it also correlated with reduced repressor function. In a sample of 30 lines, a maternal effect of repressor function did not show a pattern with latitude, nor with KP/P ratio, nor with presence or absence of P activity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 105 (1999), S. 43-62 
    ISSN: 1573-6857
    Keywords: distribution ; Drosophila ; retrotransposon ; transposable element
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We present a global analysis of the distribution of 43 transposable elements (TEs) in 228 species of the Drosophila genus from our data and data from the literature. Data on chromosome localization come from in situ hybridization and presence/absence of the elements from southern analyses. This analysis shows great differences between TE distributions, even among closely related species. Some TEs are distributed according to the phylogeny of their host specie; others do not entirely follow the phylogeny, suggesting horizontal transfers. A higher number of insertion sites for most TEs in the genome of D. melanogaster is observed when compared with that in D. simulans. This suggests either intrinsic differences in genomic characteristics between the two species, or the influence of differing effective population sizes, although biases due to the use of TE probes coming mostly from D. melanogaster and to the way TEs are initially detected in species cannot be ruled out. Data on TEs more specific to the species under consideration are necessary for a better understanding of their distribution in organisms and populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    ISSN: 1573-6857
    Keywords: Drosophila ; hobo ; hot spot ; integration specificity ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We analyzed the integration specificity of the hobo transposable element of Drosophila melanogaster. Our results indicate that hobo is similar to other transposable elements in that it can integrate into a large number of sites, but that some sites are preferred over others, with a few sites acting as integration hot spots. A comparison of DNA sequences from 112 hobo integration sites identified a consensus sequence of NTNNNNAC, but this consensus was insufficient to account for the observed integration specificity. To begin to define the parameters affecting hobo integration preferences, we analyzed sequences flanking a donor hobo element, as well as sequences flanking a hobo integration hot spot for their relative influence on hobo integration specificity. We demonstrate experimentally that sequences flanking a hobo donor element do not influence subsequent integration site preference, whereas, sequences contained within 31 base pairs flanking an integration hot spot have a significant effect on the frequency of integration into that site. However, sequence analysis of the DNA flanking several hot spots failed to identify any common sequence motif shared by these sites. This lack of primary sequence information suggests that higher order DNA structural characteristics of the DNA and/or chromatin may influence integration site selection by the hobo element.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 105 (1999), S. 239-248 
    ISSN: 1573-6857
    Keywords: transposable elements ; LTR-retroelements ; rearrangements ; population genetics ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 297 element Southern pattern modifications previously detected in mutation accumulation lines of Drosophila melanogaster were further investigated by in situ hybridisation, Southern blotting with different combinations of genomic digest-probe, and PCR. Only one out of the nine pattern modifications studied could be interpreted as an excision and was detectable by in situ hybridisation to polytene chromosomes. Results were consistent with most pattern modifications being small rearrangements within the body of the element. In agreement with the existence of spontaneous rearrangements of this kind is the observation that many genomic copies of element 297 are defective and these are not limited to heterochromatin. These findings have important implications for the models of transposable element (TE) number regulation as well as for the study of genome evolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    ISSN: 1573-6857
    Keywords: colonization ; Drosophila ; dynamic ; natural populations ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Drosophila simulans presents a large variation in copy number among various transposable elements (TEs) and among natural populations for a given element. Some elements such as HMS beagle, blood, flea, tirant, coral, prygun jockey, F, nomade and mariner are absent in most populations, except in one or two which have copies on their chromosome arms. This suggests that some TEs are being awakened in D. simulans and are in the process of invading the species while it is colonizing the world. The elements 412 and roo/B104 present a wide insertion polymorphism among D. simulans populations, but only the 412 copy number follows a temperature cline. One population (Canberra from Australia) has a very high copy number for the 412 element and for many other TEs as well, indicating that some populations may have lost control of some of their TEs. While the 412 transposition rate is similar in all populations, its transcription level throughout developmental stages varies with populations, depending on copy number. Populations with 412 copy number higher than 10–12 exhibit co-suppression, while the expression in populations with lower numbers depends on the insertion location. All these results suggest genomic invasions by 412 and other TEs during the worldwide spread of the D. simulans species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    ISSN: 1573-6857
    Keywords: Drosophila ; genome evolution ; molecular domestication ; P element ; transposable elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transposable elements are short but complex pieces of DNA or RNA containing a streamlined minimal-genome with the capacity for its selfish replication in a foreign genomic environment. Cis-regulatory sections within the elements orchestrate tempo and mode of TE expression. Proteins encoded by TEs mainly direct their own propagation within the genome by recruitment of host-encoded factors. On the other hand, TE-encoded proteins harbor a very attractive repertoire of functional abilities for a cell. These proteins mediate excision, replication and integration of defined DNA fragments. Furthermore, some of these proteins are able to manipulate important host factors by altering their original function. Thus, if the host genome succeeds in domesticating such TE-encoded proteins by taming their ‘anarchistic behavior,’ such an event can be considered as an important evolutionary innovation for its own benefit. In fact, the domestication of TE-derived cis-regulatory modules and protein coding sections took place repeatedly in the course of genome evolution. We will present prominent cases that impressively demonstrate the beneficial impact of TEs on host biology over evolutionary time. Furthermore, we will propose that molecular domestication might be considered as a resumption of the same evolutionary process that drove the transition from ‘primitive genomes’ to ‘modern’ ones at the early dawn of life, that is, the adaptive integration of a short piece of autonomous DNA into a complex regulatory network.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    ISSN: 1617-4623
    Keywords: Key words Mitochondrial proteins ; Nuclear genes ; Drosophila ; Evolutionary conservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract As a first step towards using cross-species comparison to complete the inventory of the nuclear genes that encode mitochondrial polypeptides, and ultimately to understand their function through systematic molecular and genetic analysis in a model organism of choice, we report here the characterization of 41 Drosophila melanogaster cDNAs. These cDNAs were isolated by screening an ovarian expression library with antibodies against mitochondrial proteins and identify 17 novel Drosophila genes. The deduced amino acid sequences encoded by the majority of these cDNAs turned out to show significant homology to mitochondrial proteins previously identified in other species. Among others, ORFs putatively encoding six different subunits of ATP synthase and three NADH:ubiquinone reductase subunits were detected. By in situ hybridization, all cDNAs were mapped to single bands on polytene chromosomes, thus identifying candidate Drosophila genes required for mitochondrial biogenesis and maintenance. A search of the Human Gene Index database made it possible in most cases to align the entire Drosophila coding sequence with a human consensus sequence, suggesting that the cDNAs originate from insect counterparts of expressed mammalian genes. Our experimental strategy represents an efficient approach to the identification and interspecies comparison of genes encoding products targeted to the mitochondrion.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    ISSN: 1573-5036
    Keywords: calcium ; magnesium ; nutrient flux ; osmotic hydraulic conductance ; phosphorus nutrition ; xylem exudate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Previous studies have found that P nutrition of plants is an important factor in the uptake and translocation of Mg and Ca, and increasing root osmotic hydraulic conductance (Lo) and osmotically driven xylem exudate flow (Jv). Experiments were designed to determine if the observed changes in Mg and Ca uptake and translocation, Jv, and Lo from altered P nutrition are related or are separate functions. When six-week old squash (Cucurbita pepo L.) plants grown in perlite were treated with P levels ranging from 50 to 400 μM P for seven days, Jv and Lo increased as P treatment level increased. Xylem exudate concentrations of Mg and Ca were maintained as Jv increased, resulting in an increase in total flux of these mineral elements. The increase in Mg and Ca flux in the xylem exudate correlated with increased shoot Mg and Ca levels as P nutritional level was raised. Further studies with greenhouse grown plants indicated that the increases in Jv, Lo, and Mg and Ca flux were more responsive to changes in P nutritional level than to similar changes in levels of other anions. In hydroponically grown squash plants, xylem exudate was collected for a 20 min period after 0, 2 and 4 h in treatments of 50 and 500 μM P or after P treatment was increased from 50 to 500 μM. Immediately after nutrient solution P was increased (time 0), there was a 33% increase in Jv and a 22% increase in Lo when compared to the 50 μM P treatment. The Jv and Lo of the 50–500 μM P treatment did not equal levels of the continuous 500 μM control at time 0, but were similar after 2 and 4 h. Flux of Mg and Ca did not increase as rapidly as Jv in the 50–500 treatment indicating that regulation of Mg and Ca uptake and xylem loading by P may lag behind that of water movement.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Plant molecular biology 40 (1999), S. 921-933 
    ISSN: 1573-5028
    Keywords: A23187 ; calcium ; elicitor ; MAP kinase ; Typhula ishikariensis ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Wheat cultured cells were used to study the role of Ca2+ in regulating protein kinases during the induction of defense-related genes by fungal elicitor treatments. Manipulation of intracellular Ca2+ concentrations by treatment with calcium ionophore A23187 in the presence of high extracellular Ca2+ resulted in the induction of mRNA expression of WCK-1, a gene encoding mitogen-activated protein (MAP) kinase. The induction of WCK-1 mRNA by A23187 did not occur when extracellular Ca2+ was chelated by 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA). The WCK-1 mRNA was also induced by Typhula ishikariensis-derived elicitors, suggesting a possible involvement of WCK-1 in the plant defense response against pathogens. BAPTA and a calcium channel blocker, La3+, inhibited the elicitor-induced expression of the WCK-1 mRNA. A recombinant fusion protein of WCK-1 (GST-WCK-1) autophosphorylated at the Tyr residue and exhibited an autophosphorylation-dependent protein kinase activity towards myelin basic protein. Alteration of Tyr-196 in the conserved ‘TEY’ motif in GST-WCK-1 to Phe by site-directed mutagenesis abolished the autophosphorylation. The GST-WCK-1 protein was activated by elicitor-treated wheat cell extracts but not by the control extract. These results suggest that fungal elicitors activate WCK-1, a specific MAP kinase in wheat. Furthermore, the results suggest a possible involvement of Ca2+ in enhancing the MAP kinase signaling cascade in plants by controlling the levels of the MAP kinase transcripts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    ISSN: 1573-5036
    Keywords: Atlantic white cedar ; calcium ; magnesium ; potassium ; nutrient resorption ; nutrient use efficiency ; wood chemical composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nutrient resorption from senescing tissues increases plant nutrient-use efficiency, and may be an adaptation to nutrient limitation. In some tree species, retranslocation of nutrients from sapwood during heartwood formation is a comparable process. We measured Ca, Mg and K concentrations in Atlantic white cedar (Chamaecyparis thyoides) stemwood samples taken from two swamps in the northeastern United States and compared them to soil mineral nutrient availability at each site. We found that Ca, Mg and K concentrations were 60–700% higher in sapwood than in the immediately adjacent heartwood, indicating retranslocation of these nutrients from senescing sapwood. Sapwood nutrient concentrations were similar between the two sites. However, nutrient concentrations in the heartwood differed significantly between the sites, as did the relative degree of Ca and Mg retranslocation from senescing sapwood. We found these differences between sites to be inversely related to significant differences in exchangeable Ca, Mg and K as well as Al concentrations in the soil. These findings suggest that the degree of nutrient retranslocation from senescing sapwood may be influenced by soil nutrient availability.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    ISSN: 1573-5117
    Keywords: shallow lake ; sediment ; dy ; phosphorus ; calcium ; metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A chemical characterization of the surficial sediment (0–20 cm) of type `dy' (org-Cpart/TNpart〉10) of the anthropogenically polluted shallow Lake Petersdorf is presented. Eighty samples were analyzed for a set of parameters, i.e. dry weight, loss on ignition (LOI), total inorganic carbon (TIC), N, S, P, Ca, Si, As, Fe, Al, Mn, Zn, Cd, and Pb. LOI, TIC, N, S, Ca, P, and Zn tend to accumulate at a water depth 〉2 m (70.6% of the lake surface) in contrast to Mn and Fe which are more widely distributed, and Cd and Pb which are accumulated in the lake part close to a road. The enrichment factors of certain elements, e.g. Al (23.9%), Si (31.5%), P (12.2%), and Ca (68.7%) from 20 cm sediment depth up to the surface, are attributed to incisive changes in the immediate catchment. Erosion, fertilization, amelioration, and separation of the peatland north of the lake by a dam within the last 60 yrs resulted in the change of Lake Petersdorf from a dystrophic to a eutrophic stage. This enhanced the mineralization of its meso-humic (LOI/TNpart=20.6) sediment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Biogeochemistry 47 (1999), S. 333-351 
    ISSN: 1573-515X
    Keywords: base cations ; calcium ; forest ecosystem ; mobile anions ; soil acidification ; surface-water acidification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Anion fluxes from a forest soil are usually correlated with those of base cations (BC). Declines in base cation deposition or long-term depletion from the soil may change these relationships. We used multiple regression to identify biogeochemical variables predicting annual volume-weighted concentrations of BC in streamwater draining a forested watershed, and analysis of variance to compare the effects of Ca and Cl inputs on BC fluxes out of soil horizons in irrigated plots. For the watershed, anion concentrations in streamwater predicted BC export most precisely (R2 = 0.84). The best two-variable model (adjusted R2 = 0.91) also included BC concentration in bulk deposition. Consistent with predictions from equations governing exchange chemistry, the proportion of charge contributed by Ca2+ increased with increasing total anion concentration, while that of Na+ decreased. At the plot scale, Cl- concentrations in treatment solutions had a stronger effect (p = 0.06) on BC concentration in Oa-horizon solutions than did Ca2+ concentrations (p = 0.33). In individual horizons of individual plots, BC and total ion concentrations were correlated, but cation composition was not consistent within horizons from different plots. This study detected no evidence of long-term cation depletion in the soils controlling streamwater, but did detect extremely base-poor plots. Because acid deposition affects surface horizons first, streamwater chemistry may not be an adequate way to assess nutrient supply of forest soils.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Biogeochemistry 47 (1999), S. 335-353 
    ISSN: 1573-515X
    Keywords: base cations ; calcium ; forest ecosystem ; mobile anions ; soil acidification ; surfacewater acidification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Anion fluxes from a forest soil are usually correlated with those of base cations (BC). Declines in base cation deposition or long-term depletion from the soil may change these relationships. We used multiple regression to identify biogeochemical variables predicting annual volume-weighted concentrations of BC in streamwater draining a forested watershed, and analysis of variance to compare the effects of Ca and Cl inputs on BC fluxes out of soil horizons in irrigated plots. For the watershed, anion concentrations in streamwater predicted BC export most precisely (R 2=0.84). The best two-variable model (adjustedR 2=0.91) also included BC concentration in bulk deposition. Consistent with predictions from equations governing exchange chemistry, the proportion of charge contributed by Ca2+ increased with increasing total anion concentration, while that of Na+ decreased. At the plot scale, Cl− concentrations in treatment solutions had a stronger effect (p=0.06) on BC concentration in Oa-horizon solutions than did Ca2+ concentrations (p=0.33). In individual horizons of individual plots, BC and total ion concentrations were correlated, but cation composition was not consistent within horizons from different plots. This study detected no evidence of longterm cation depletion in the soils controlling streamwater, but did detect extremely base-poor plots. Because acid deposition affects surface horizons first, streamwater chemistry may not be an adequate way to assess nutrient supply of forest soils.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    ISSN: 1573-6857
    Keywords: alcoholic resources ; Drosophila ; habitat selection ; Indian subcontinent ; short range variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In five Indian localities, it was possible to collect D. melanogaster in two different types of habitats, namely ordinary domestic and alcohol rich ones. Tolerance and utilization capacity of several alcohols and of acetic acid were analyzed in a total of 10 local populations. Results on two other species (D. repleta and D. immigrans) were also available from one place. In each locality, the population from alcohol rich habitat proved to be more tolerant to all the investigated products and also to be more capable of using them as a resource. Alcohols toxicity increased with increasing carbon chain length and secondary alcohols were more toxic than primary ones. Utilization capacity of all products was relatively independent of their toxicity. Especially acetic acid, the toxicity of which was low and similar to that of ethanol, was always a fairly poor resource. From a genetic point of view, tolerance and utilization capacity appeared as two relatively independent traits. Natural selection, which is responsible for the genetic differentiation of local populations, is likely to act simultaneously on both traits.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 107 (1999), S. 103-111 
    ISSN: 1573-6857
    Keywords: Drosophila ; genome evolution ; model organisms ; transposons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Model organisms have proved to be highly informative for many types of genetic studies involving ‘conventional’ genes. The results have often been successfully generalized to other closely related organisms and also, perhaps surprisingly frequently, to more distantly related organisms. Because of the wealth of previous knowledge and their availability and convenience, model organisms were often the species of choice for many of the earlier studies of transposable elements. The question arises whether the results of genetic studies of transposable elements in model organisms can be extrapolated in the same ways as those of conventional genes? A number of observations suggest that special care needs to be taken in generalizing the results from model organisms to other species. A hallmark of many transposable elements is their ability to amplify rapidly in species genomes. Rapid spread of a newly invaded element throughout a species range has also been demonstrated. The types and genomic copy numbers of transposable elements have been shown to differ greatly between some closely related species. Horizontal transfer of transposable elements appears to be more frequent than for nonmobile genes. Furthermore, the population structure of some model organisms has been subject to drastic recent changes that may have some bearing on their transposable element genomic complements. In order to initiate discussion of this question, several case studies of transposable elements in well-studied Drosophila species are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 107 (1999), S. 95-102 
    ISSN: 1573-6857
    Keywords: Drosophila ; genomic regulation ; telomeric activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The structural integrity of TART elements has been used as reporter of instability at chromosomal ends in numerous Drosophila stocks and over time in an unstable stock. The results show that telomeric activity is a regulated process that may differ between the stocks as well as over time within a stock.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    Springer
    Chromosome research 7 (1999), S. 449-460 
    ISSN: 1573-6849
    Keywords: Apis ; Bombyx ; Drosophila ; Ephestia ; fluorescence in-situ hybridization (FISH) ; Galleria ; Gammarus ; insect phylogeny ; Ips ; Locusta ; Megaselia ; Pyrrhocoris ; Southern hybridization ; Tegenaria ; telomere ; Tenebrio
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied the occurrence of the TTAGG telomere repeats by fluorescence in-situ hybridization (FISH) and Southern hybridization in ten insect species and two other arthropods. (TTAGG)n-containing telomeres were found in three Lepidoptera species, the silkworm Bombyx mori (in which the telomeric sequence was recently discovered), the flour moth Ephestia kuehniella, and the wax moth Galleria mellonella, in one species of Hymenoptera, the honey bee Apis mellifera, in one species of Coleoptera, the bark beetle Ips typographus, in one species of Orthoptera, the locust Locusta migratoria, and in a crustacean, the amphipod Gammarus pulex. They were absent in another species of Coleoptera, the mealworm Tenebrio molitor, two representatives of Diptera, Drosophila melanogaster and Megaselia scalaris, a species of Heteroptera, the bug Pyrrhocoris apterus and a spider, Tegenaria ferruginea. Our results, which confirm and extend earlier observations, suggest that (TTAGG)n was a phylogenetically ancestral telomere motif in the insect lineage but was lost independently in different groups, being replaced probably by other telomere motifs. In the Coleoptera this must have happened rather recently as even members of the same family, Curculionidae, differ with respect to the telomeric DNA.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 581-590 
    ISSN: 1573-6881
    Keywords: Mitochondria ; triarylmethane dyes ; photodynamic therapy ; respiration ; mitochondrial permeability transition ; cyclosporin A ; calcium ; proton transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The mitochondrial effects of submicromolar concentrations of six triarylmethane dyes, withpotential applications in antioncotic photodynamic therapy, were studied. All dyes promotedan inhibition of glutamate or succinate-supported respiration in uncoupled mitochondria, in amanner stimulated photodynamically. No inhibition of N,N,N′,N′-tetramethyl-p-phenylenediamine(TMPD) supported respiration was observed, indicating that these dyes do not affectmitochondrial complex IV. When mitochondria were energized with TMPD in the absence ofan uncoupler, treatment with victoria blue R, B, or BO, promoted a dissipation of mitochondrialmembrane potential and increase of respiratory rates, compatible with mitochondrialuncoupling. This effect was observed even in the dark, and was not prevented by EGTA, Mg2+ orcyclosporin A, suggesting that it is promoted by a direct effect of the dye on inner mitochondrialmembrane permeability to protons. Indeed, victoria blue R, B, and BO promoted swellingof valinomycin-treated mitochondria incubated in a hyposmotic K+-acetate-based medium,confirming that these dyes act as classic protonophores such as FCCP. On the other hand, ethylviolet, crystal violet, and malachite green promoted a dissipation of mitochondrial membranepotential, accompanied by mitochondrial swelling, which was prevented by EGTA, Mg2+, andcyclosporin A, demonstrating that these drugs induce mitochondrial permeability transition.This mitochondrial permeabilization was followed by respiratory inhibition, attributable tocytochrome c release, and was caused by the oxidation of NAD(P)H promoted by these drugs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    ISSN: 1573-6857
    Keywords: Drosophila ; nasuta-albomicans ; complex ; cytoraces ; body size ; fertility ; ovariole number ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Our long range interracial hybridization experiments between a pair of cross fertile races, Drosophila nasuta (2n = 8) and D.albomicans (2n = 6) have resulted in the evolution of two new karyotypic strains under laboratory conditions, which are named as Cytorace 1 and Cytorace 2. These Cytoraces harbor chromosomes from both parents. Here, we compare the body size of the parental races and newly evolved Cytoraces and the relationship between the body size and fitness. Analysis reveals that the parental races have reduced fertility and are larger in body size than newly evolved Cytoraces. Thus, the newly evolved Cytoraces show reduced body size and better fitness in the course of their evolution.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Photosynthesis research 60 (1999), S. 111-150 
    ISSN: 1573-5079
    Keywords: calcium ; copper ; iron ; manganese ; oxygen evolution ; phylogeny ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Iron is the quantitatively most important trace metal involved in thylakoid reactions of all oxygenic organisms since linear (= non-cyclic) electron flow from H2O to NADP+ involves PS II (2–3 Fe), cytochrome b6-f (5 Fe), PS I (12 Fe), and ferredoxin (2 Fe); (replaceable by metal-free flavodoxin in certain cyanobacteria and algae under iron deficiency). Cytochrome c6 (1 Fe) is the only redox catalyst linking the cytochrome b6-f complex to PS I in most algae; in many cyanobacteria and Chlorophyta cytochrome c6 and the copper-containing plastocyanin are alternatives, with the availability of iron and copper regulating their relative expression, while higher plants only have plastocyanin. Iron, copper and zinc occur in enzymes that remove active oxygen species and that are in part bound to the thylakoid membrane. These enzymes are ascorbate peroxidase (Fe) and iron-(cyanobacteria, and most al gae) and copper-zinc- (some algae; higher plants) superoxide dismutase. Iron-containing NAD(P)H-PQ oxidoreductase in thylakoids of cyanobacteria and many eukaryotes may be involved in cyclic electron transport around PS I and in chlororespiration. Manganese is second to iron in its quantitative role in the thylakoids, with four Mn (and 1 Ca) per PS II involved in O2 evolution. The roles of the transition metals in redox catalysts can in broad terms be related to their redox chemistry and to their availability to organisms at the time when the pathways evolved. The quantitative roles of these trace metals varies genotypically (e.g. the greater need for iron in thylakoid reactions of cyanobacteria and rhodophytes than in other O2-evolvers as a result of their lower PS II:PS I ratio) and phenotypically (e.g. as a result of variations in PS II:PS I ratio with the spectral quality of incident radiation).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 415 (1999), S. 319-322 
    ISSN: 1573-5117
    Keywords: calcium ; plasmalemma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cladophora glomerata (L.) Kz. was grown in Jaworski's algal culture medium and exposed to a fluctuating electromagnetic field which induced development of dark colouration, increased density and brittleness. After 4 weeks exposure, algae were unable to grow when transferred to unexposed culture medium. In addition, algal growth in culture medium exposed to a fluctuating magnetic field before the algae were introduced, was inhibited significantly compared with an appropriate control after 4 days, indicating a transfer of effect from the brief exposure to a magnetic field of less than 1 second to the 4-day period when growth was active.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    ISSN: 1573-6822
    Keywords: ATP ; energy metabolism ; calcium ; diltiazem ; rat liver perfusion ; ATP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Diltiazem causes vasoconstriction in the liver when present at high concentrations, an action that is strictly Ca2+-dependent. Diltiazem is also active on energy metabolism. This toxic action could be partly a consequence of hemodynamic effects. In the absence of Ca2+, the hemodynamic effects are no longer present and, consequently, Ca2+-free experiments are useful for distinguishing between hemodynamics-dependent and hemodynamics-independent effects. The experimental system used was the hemoglobin-free perfused rat liver from fed and fasted rats. Diltiazem was infused at various concentrations in the presence and absence of Ca2+. Several metabolic parameters were measured: lactate and pyruvate production (glycolysis), glycogenolysis, oxygen uptake, gluconeogenesis, and the cellular levels of lactate, pyruvate, glucose, AMP, ADP, and ATP. The effects of diltiazem can be divided into three groups: (1) Effects that are strictly dependent on the Ca2+-mediated hemodynamic action. This group comprises inhibition of oxygen uptake at all concentrations (50–500 μmol/L) inhibition of lactate, pyruvate, and glucose release at high concentrations; the decrease in cellular ATP; the increase in cellular AMP; and the cellular accumulation of glucose and lactate. (2) Effects that are independent of the hemodynamic action. The most relevant effect of this type is inhibition of gluconeogenesis. (3) Effects that are influenced by Ca2+ but are independent of the hemodynamic effects. This is the typical case of lactate and glucose release from endogenous glycogen, whose stimulation by low diltiazem concentrations is more pronounced in the presence of Ca2+ than in its absence.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    Electronic Resource
    Electronic Resource
    Springer
    Chromosome research 7 (1999), S. 445-448 
    ISSN: 1573-6849
    Keywords: chromosomes ; cytological technique ; Drosophila ; embryos ; mitosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    ISSN: 1573-6857
    Keywords: Drosophila ; heritability ; principal component analysis ; shape ; size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract ‘Traditional morphometrics’ allows us to decompose morphological variation into its major independent sources, identifying them usually as size and shape. To compare and investigate the properties of size and shape in natural populations of Drosophila mediopunctata, estimating their heritabilities and analysing their temporal and microgeographic changes, we carried out collections on seven occasions in Parque Nacional do Itatiaia, Brazil. In one of these collections, we took samples from five different altitudes. Measurements were taken from wild caught inseminated females and up to three of their laboratory‐reared daughters. Through a principal component analysis, three major sources of variation were identified as due to size (the first one) and shape (the remaining two). The overall amount of variation among laboratory flies was about half of that observed among wild flies and this reduction was primarily due to size. Shape variation was about the same under natural and artificial conditions. A genetic altitudinal cline was detected for size and shape, although altitude explained only a small part of their variation. Differences among collections were detected both for size and shape in wild and laboratory flies, but no simple pattern emerged. Shape variation had high heritability in nature, close to or above 40% and did not vary significantly temporally. Although on the overall size heritability (18 ± 6%)was significant its estimates were not consistent along months – they were non‐significant in all but one month, when it reached a value of 51 ± 11%. Overall, this suggests that size and shape have different genetic properties.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    ISSN: 1573-2932
    Keywords: acidification ; Brown trout ; calcium ; density ; juveniles ; streams
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract We examined the relationship between young brown trout ( Salmo trutta) density in lake tributaries, and water chemistry and habitat variables. The study was carried out during the autumn in three acidic, softwater river systems in western and southwestern Norway; Gaular and Vikedal (1987–1993) and Bjerkreim (1988–1993). The streams had mean calcium concentrations of 0.35 mg L-1 (Gaular), 0.52 mg L-1 (Vikedal) and 0.84 mg L-1 (Bjerkreim). The concentration of inorganic Al was generally low, with mean values of 8.40 (Gaular), 22.22 (Vikedal) and 43.36 μg L-1 (Bjerkreim). In multiple regressions that involved different water chemistry variables, brown trout density correlated best with calcium concentration and with a combination of calcium and pH; the Ca2+:H+ ratio. In Vikedal and Gaular, calcium explained 51 and 57%, respectively, of the variability in brown trout densities. Althoug alkalinity exhibited the best correlation with brown trout density in Bjerkreim ( r2=0.33), it was similar to that of the model that included all major ions plus pH. The Ca2+:H+ ratio had a larger effect for variability in brown trout density in Gaular (r2=0.66) than calcium alone. In Vikedal and Bjerkreim, the Ca2+:H+ ratio also correlated with brown trout density, but considerably less than in Gaular. The predictive power of habitat variables was much lower than that of water chemistry; the single most important factors were altitude in Gaular (r2=0.22), mean water temperature in Vikedal (r2=0.11) and depth SD (index of heterogeneity) in Bjerkreim (r2=0.07). Models that included both habitat and water chemistry variables showed that the density of young brown trout was predicted primarily by calcium concentrations in Gaular (r2=0.75) and Vikedal (r2=0.54), as opposed to pH in Bjerkreim (r2=0.25). Habitat had low effect in all three river systems (r2=0.01–0.04). The final model explained 86, 68 and 32%, respectively, of the variability in brown trout density in the three catchments. Thus, water chemistry variables seem to be factors that limit the density of young brown trout in acidic softwater streams.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 16 (1999), S. 1483-1486 
    ISSN: 1573-904X
    Keywords: calcium ; responsive ; α-amylase ; starch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 110 (1999), S. 421-432 
    ISSN: 1573-2932
    Keywords: calcium ; coal fly ash ; gypsum ; pH ; selenium ; soil ; sulfur ; trace element
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Selenium, a potentially toxic trace element, is present in coal fly ash and is accumulated by plants growing on ash landfills. Application of gypsum (CaSO4·2H2O) can reduce Se accumulation. The persistence of this effect and the efficacy of repeated gypsum applications were investigated in forbs and grasses on a soil-capped, fly ash landfill near Lansing, New York. Gypsum was applied as a top-dressing at a rate of 0 or 11.2 t ha-1 in 1990 to three plots, and one-half of each of these plots received an additional top dressing of gypsum at 11.2 t ha-1 in 1991, producing four treatments – no gypsum, gypsum only in 1990, gypsum only in 1991, and gypsum in both years. Vegetation was harvested in July and October of 1991 and in July of 1992 and analyzed for Se, S, and Ca. Application of gypsum: (1) decreased Se accumulation by forbs and grasses harvested later in the season; (2) decreased Se accumulation in a subsequent year; (3) produced no further decrease when reapplied in a second year; and (4) did not decrease Se accumulation two years after a single application. The decrease in Se accumulation was not due to dilution caused by S fertilization. Variation in Se accumulation was not explained by variation in the pH and Se concentration of the soil and ash.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 116 (1999), S. 461-477 
    ISSN: 1573-2932
    Keywords: calcium ; exchangeable base cations ; nitrogen ; potential acid ; Schoenus nigricans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The atmospheric input of nitrogen and potantial acid, and the composition of the leachate from the topsoil layer are quantified for eight dune slack sites differing in plant composition, on the Frisian islands of Terschelling and Schiermonnikoog. Basiphilous mesotrophic communities with many rare plant species grow in one site on Terschelling and two sites on Schiermonnikoog. Samples were taken in the period mid May 1992 – mid May 1993. Bulk atmospheric nitrogen deposition measured in an open collector was between 15–20 kg ha−1 yr−1 for the eight sites. On Terschelling, the deposition was slightly higher than on Schiermonnikoog. Ammonium was a third of the total amount of nitrogen deposited on Terschelling and half the amount of nitrogen deposited on Schiermonnikoog. The deposition of potential acid varied from 490 to 810 mol ha−1 yr−1. On Terschelling, the amount of potential acid was highest and around 800 mol ha−1 yr−1 for both sites. On Schiermonnikoog, the amount of potential acid was lowest for the dune slacks in the north-western part of the island and it showed an increase for slacks towards the eastern part of the island. Calcium is the main cation leached from the topsoil followed by sodium, magnesium and potassium. Nitrogen or ammonium hardly leached from the topsoil layer. The shift from basiphilous pioneer communities toward older and more acid stages of dune slack succession appears to be caused primarily by leaching of base cations rather than eutrophication.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    World journal of microbiology and biotechnology 15 (1999), S. 647-649 
    ISSN: 1573-0972
    Keywords: Aspergillus niger ; calcium ; citric acid ; fungal morphology ; molasses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The effect of CaCl2 on the growth, morphology and citric acid production from sugarcane molasses by Aspergillus niger 419 was studied. The addition of 0.5g CaCl2/l to the fermentation medium induced a loose pelleted form of growth, reduced the biomass concentration and increased the volumetric productivity (g citric acid/h) and the specific production (g citric acid/g biomass dw) from 0.02 and 0.37 to 0.13 and 3.72, respectively.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    International journal of peptide research and therapeutics 6 (1999), S. 349-352 
    ISSN: 1573-3904
    Keywords: calcium ; endothelial cells ; metalloendopeptidase EC 3.4.24.16 ; secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The two closely related soluble zinc metalloendopeptidases EC 3.4.24.15 (EP24.15) and EC 3.4.24.16 (EP24.16) readily hydrolyze the vasocative peptide bradykinin in vitro, and therefore may play a role in cardiovascular regulation. Although primarily soluble cytosolic enzymes, both secreted and membrane-associated forms of both peptidases have been reported. However, these enzymes have neither a transmembrane domain nor a signal sequence; thus, the mechanisms of membrane anchoring and secretion are unknown. In the present study, secreted/released EP24.15 and EP24.16 activity from aortic endothelial cells in culture was assessed by the cleavage of a specific quenched fluorescent substrate. An increase in enzyme activity released from endothelial cells, which express both peptidases, was seen following incubation with calcium-free media. In the AtT-20 endocrine cell (mouse pituitary corticotrope), which predominantly expresses EP24.15, the release of activity into media was unaffected by calcium removal. The release of enzyme activity from endothelial cells was inversely proportional to calcium concentrations ranging between 0.01 mM (activity equivalent to calcium-free media) and 0.5 mM (activity equivalent to normal media). Cleavage of the EP24.16-specific substrate AcNT8–13 indicated that the increase in enzyme activity released upon incubation with calcium-free medium was due at least in part to the release of EP24.16. These results suggest that EP24.15 and EP24.16 are secreted from endothelial cells, and that removal of calcium selectively enhances the release of EP24.16 by an as yet unknown mechanism.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    International journal of peptide research and therapeutics 6 (1999), S. 349-352 
    ISSN: 1573-3904
    Keywords: calcium ; endothelial cells ; metalloendopeptidase EC 3.4.24.16 ; secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The two closely related soluble zinc metalloendopeptidases EC 3.4.24.15 (EP24.15) and EC 3.4.24.16 (EP24.16) readily hydrolyze the vasoactive peptide bradykinin in vitro, and therefore may play a role in cardiovascular regulation. Although primarily soluble cytosolic enzymes, both secreted and membrane-associated forms of both peptidases have been reported. However, these enzymes have neither a transmembrane domain nor a signal sequence; thus, the mechanisms of membrane anchoring and secretion are unknown. In the present study, secreted/released EP24.15 and EP24.16 activity from aortic endothelial cells in culture was assessed by the cleavage of a specific quenched fluorescent substrate. An increase in enzyme activity released from endothelial cells, which express both peptidases, was seen following incubation with calcium-free media. In the AtT-20 endocrine cell (mouse pituitary corticotrope), which predominantly expresses EP24.15, the release of activity into media was unaffected by calcium removal. The release of enzyme activity from endothelial cells was inversely proportional to calcium concentrations ranging between 0.01 mM (activity equivalent to calcium-free media) and 0.5 mM (activity equivalent to normal media). Cleavage of the EP24.16-specific substrate AcNT8-13 indicated that the increase in enzyme activity released upon incubation with calcium-free medium was due at least in part to the release of EP24.16. These results suggest that EP24.15 and EP24.16 are secreted from endothelial cells, and that removal of calcium selectively enhances the release of EP24.16 by an as yet unknown mechanism.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Behavior genetics 29 (1999), S. 65-73 
    ISSN: 1573-3297
    Keywords: Mating behavior ; reproductive isolation ; sexual isolation ; sibling species ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract In an investigation into the effects of developmental isolation from all conspecifics, the Drosophila willistoni group of six sibling species responded to differing degrees: all six are reproductively isolated from D. paulistorum, the tester species. Drosophila pavlovskiana, a narrow endemic, proved the most vulnerable, responding by reducing its adult sexual isolation, if eggs, any instar, and sometimes even pupae were socially isolated. To lesser degrees, D. tropicalis and D. willistoni both produced similar results only when their eggs were isolated, i.e., when from the moment of egg deposition on, there was absolutely no contact with other flies until testing for mating behavior. The remaining siblings, D. equinoxialis and D. insularis, were immovable.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    ISSN: 1573-3297
    Keywords: Drosophila ; oviposition-site preference ; alcohol dehydrogenase ; transgene coplacement ; ethanol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Psychology
    Notes: Abstract The preference of Drosophila females to lay eggs on substrates that do or do not contain alcohol is an excellent system to study the evolutionary genetics of behavior, because (1) there is variation in this behavior within and among species, (2) the behavior is amenable to laboratory investigation, and (3) the behavior presumably has a direct relationship to reproductive fitness. Moreover, a key genetic component of the system, the Alcohol dehydrogenase (Adh) locus, is arguably the most well characterized gene known. However, because the Adh gene and its genetic background are inseparable in reproductively isolated species, it is difficult to establish its role in behavioral divergence. By transgene coplacement, we created pairs of strains of D. melanogaster expressing an Adh allele from either D. melanogaster or D. affinidisjuncta, a Hawaiian species with very low levels of ADH in adults. When raised on ethanol-containing medium, the affinidisjuncta–Adh strains experience high mortality relative to the melanogaster–Adh strains. However, affinidisjuncta–Adh females show the same preference for oviposition on ethanol-containing medium as melanogaster–Adh females. Thus, preference for ethanol in these strains is not determined primarily by Adh genotype.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Evolutionary ecology 13 (1999), S. 211-220 
    ISSN: 1573-8477
    Keywords: Drosophila ; evolutionary genetics ; host specificity ; parasitoid ; virulence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The developmental success of Leptopilina boulardi parasitoids within host species of the melanogaster subgroup is determined mainly by their ability to suppress the host immune reaction (virulence). Host resistance and parasitoid virulence are genetically variable in both partners. A gene for specific resistance against L. boulardi (Rlb) has been identified in Drosophila melanogaster, and a gene for the immune suppression (IS) of D. melanogaster has been identified in L. boulardi. To understand the evolution of the IS gene, we determined its specificity regarding potential hosts of the melanogaster subgroup. It did not affect the virulence against any other species of the melanogaster subgroup and was called ISm for immune suppression of D. melanogaster. Another gene (ISy), non-linked to the gene ISm, was characterized for the specific immune suppression of D. yakuba. These results suggesting that natural selection for virulence against one host species does not influence the evolution of virulence against another will allow us to develop pertinent hypotheses concerning the evolution of this character which is expected to drive the evolution of the parasitoid toward narrow host specialization.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    ISSN: 1573-8221
    Keywords: magnesium ; dringking water ; arterial pressure ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Magnesium deficiency in drinking water increases calcium-accumulating capacity of the aortic and myocardial walls in normotensive WKY rats, induces Ca resorption from bones, and impairs compartmentalization of membrane-bound Ca in platelets, resulting in accumulation of Ca in the external plasma membrane without changing blood pressure. Increased systolic blood pressure was characteristic of rats in Ca-deficient groups.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 13-24 
    ISSN: 1570-7458
    Keywords: Drosophila ; cytoplasmic incompatibility ; Wolbachia ; temperature ; antibiotics ; density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of high temperatures, antibiotics, nutrition and larval density on cytoplasmic incompatibility caused by a Wolbachia infection were investigated in Drosophila simulans. Exposure of larvae from an infected stock to moderate doses of tetracycline led to complete incompatibility when treated females were crossed to infected males; the same doses only caused a partial restoration of compatibility when treated males were crossed to uninfected females. In crosses with treated females, there was a strong correlation between dose effects on hatch rates and infection levels in embryos produced by these females. Ageing and rearing males at a high temperature led to increased compatibility. However, exposing infected females to a high temperature did not influence their compatibility with infected males. Male temperature effects depended on conditions experienced at the larval stage but not the pupal stage. Exposure to 25 °C reduced the density of Wolbachia in embryos compared with a 19 °C treatment. Low levels of nutrition led to increased compatibility, but no effect of larval crowding was detected. These findings show the ways environmental factors can influence the expression of cytoplasmic incompatibility and suggest that environmental effects may be mediated by bacterial density.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    Springer
    Journal of insect behavior 11 (1998), S. 691-712 
    ISSN: 1572-8889
    Keywords: cactus ; Drosophila ; geographic variation ; host preference behavior ; Sonoran Desert ; volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous studies have suggested that all populations of cactophilic Drosophila mojavensis prefer pitaya agria cactus, Stenocereus gummosus, over all other potential hosts for feeding and breeding, including populations that inhabit areas where no agria grows. We sampled five geographically isolated populations of D. mojavensis from nature to assess host choice within and between populations. Host choice tests were performed in a laboratory “olfactometer” by allowing adult D. mojavensis to choose between plumes of synthetic volatile cocktails of two widespread host cacti. Overall, each population showed significant preference for agria volatiles with one exception: a mainland Sonora population that uses organ pipe cactus in nature exhibited preference for organ pipe volatiles, suggesting a possible shift in host preference. The degree of preference for agria volatiles was greatest in a population from southern California that use California barrel cactus as a host. Since southern Californian populations of D. mojavensis are thought to be derived from those in Baja California, preference for agria volatiles is considered a retained ancestral trait. Three populations from Baja California and mainland Mexico that use agria in the wild expressed lower, but similar preferences for agria volatiles. Because populations of D. mojavensis are ancestral to those in mainland Mexico, Arizona, and California, the shift from agria to alternate hosts has not been accompanied by strong changes in host preference behavior.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    ISSN: 1572-8889
    Keywords: courtship behavior ; songs ; sexual isolation ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four species of the Drosophila virilis group, D. montana, D. littoralis, D. lummei, and D. ezoana, occur sympatrically in several locations in northern Europe. Courtship interactions between the flies of the three first-mentioned species were observed at malt baits in Kemi, northern Finland, to find out how the flies of different species recognize conspecific individuals and how interspecific courtships differ from intraspecific ones in the wild. Intraspecific courtships (including females of different reproductive stages) and interspecific courtships were also videotaped and analyzed in laboratory. In the wild the males courted both conspecific and allospecific females, even though the species varied in how much the males were attracted to females of different species. Interspecific courtships usually broke off when the male touched the female or when the male and/or the female vibrated his/her wings, producing acoustic cues. In the laboratory males courted conspecific females irrespective of the reproductive stage of the female, even though the courtships directed toward immature and fertilized females usually included only orienting and touching (no licking and singing). D. littoralis, and very rarely D. montana and D. lummei, males courted also allospecific females. In the few interspecific courtships between these three species, where the male proceeded to singing, females responded to male singing by vibrating their wings. This ended the courtship. It is suggested that both the chemical cues affecting female attractivity and the acoustic signals of males and females, which are produced by wing vibration, function in maintaining sexual isolation between these three species.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 11 (1998), S. 359-372 
    ISSN: 1572-8773
    Keywords: calcium ; EGF-domains ; cadherins ; integrins ; calmodulin ; cytoskeleton ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The known roles for calcium-binding proteins in developmental signaling pathways are reviewed. Current information on the calcium-binding characteristics of three classes of cell-surface developmental signaling proteins (EGF-domain proteins, cadherins and integrins) is presented together with an overview of the intra-cellular pathways downstream of these surface receptors. The developmental roles delineated to date for the universal intracellular calcium sensor, calmodulin, and its targets, and for calcium-binding regulators of the cytoskeleton are also reviewed.© Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 27 (1998), S. 435-454 
    ISSN: 1572-8927
    Keywords: EDTA ; HEDTA ; NTA ; IDA ; solubility ; strontium ; calcium ; waste processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The effects of calcium, hydroxide, and carbonate on the displacement of Sr from four organic chelates: ethylenedinitrilotetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenedinitrilotriacetic acid (HEDTA) nitrilotriacetic acid (NTA), and iminidiacetic acid (IDA) was studied in solutions with high base and carbonate concentration. Comparison of solutions with and without added chelators allowed the speciation changes in solution to be directly determined. Increases in both carbonate and calcium concentration were effective in displacing Sr from the chelators even under high carbonate concentration. Increases in hydroxide were ineffective in removal of Sr from the chelators, even at base concentrations as high as 6M. Under certain specific conditions, most notably when both CaCO3(s) and SrCO3(s) are present in solution, chemical equilibrium constraints result in cancelation of activity coefficient changes for aqueous Sr and Ca organic chelate complexes. Under such conditions the predicted ratios of chelated Ca and Sr become independent of the ionic media and predictive relations using known equilibrium constants give very good representations of the experimental data. These results indicate that manipulation of metal ion displacement reactions during chemical processing of Sr–chelate solutions can result in the displacement of Sr from organic chelators. The implications of such strategies in processing high level waste supernatants stored at Department of Energy (DOE) sites is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    ISSN: 1572-8889
    Keywords: Drosophila ; courtship song ; behavior ; female choice ; sexual isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The courtship behavior and the effects of courtship song in inter- and intraspecific crosses were studied in the four sympatric species of the Drosophila auraria complex: D. auraria, D. biauraria, D. subauraria, and D. triauraria. Orientation, tapping, and vibration (the repertoires of male courtship) were observed in both inter- and intraspecific crosses, suggesting that signals from heterospecific females were enough to elicit such male behaviors. The crossability tests with wingless or winged heterospecific males (tests for wing effects) revealed that winged heterospecific males copulated less than wingless ones in all four species but not all the pairwise cases. Since the crossability tests with aristaless females (deaf) or normal females showed essentially the same results as the tests for wing effects, we concluded that the sound produced by wing vibration plays an important role and that the wing movement itself is less important. These findings suggest that courtship songs are of great importance in mate discrimination and the sexual isolation between the species of this complex.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 11 (1998), S. 375-382 
    ISSN: 1572-8773
    Keywords: apoptosis ; programmed cell death (PCD) ; calcium ; DAP-Kinase ; calcineurin ; ALG-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract In this chapter various aspects of apoptosis or programmed cell death (PCD) influenced by calcium as a mediator of signal transduction have been reviewed. Attention has been focused on recently described calcium-binding proteins such as ALG-2 or on a new calcium/calmodulin-dependent kinase, the death asso-ciated protein kinase or DAP-kinase. Both play a central role in apoptotic processes. Calcineurin, which normally is involved in the regulation of T-cell proliferation, is reported to interact with the apoptosis protec-tion protein bcl-2. Its possible involvement in the decision process whether T-cell activation leads to prolif-eration or apoptosis is discussed.© Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 11 (1998), S. 399-404 
    ISSN: 1572-8773
    Keywords: calcium ; membrane ; phospholipids ; annexin ; exocytosis ; anticoagulation ; ion channel ; secretion ; cytoskeleton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The annexins are a family of proteins that bind anionic phospholipid surfaces in a Ca 2+ -dependent manner (general reviews include Raynal & Pollard 1994, Swairjo & Seaton 1994, Seaton 1996, Mollenhauer, 1997). Due to this functional property, individual annexins have been discovered independently by numerous labo-ratories with diverse experimental goals. Ca 2+ characteristically causes the annexins to shift from a soluble to membrane associated state. This shift is believed to be the mechanism that underlies annexin cellular function.© Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 11 (1998), S. 345-358 
    ISSN: 1572-8773
    Keywords: calcium ; CREB ; gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Through the evolution of multicellular organisms, calcium has emerged as the preferred ion for intracel-lular signalling. It now occupies a pivotal role in many cell types and nowhere is it more important than in neurons, where it mediates both the relaying and long-term storage of information. The latter is a process that enables learning and memory to be formed and requires the activation of gene expression by calcium signals. Evidence from a number of diverse organisms shows that transcription mediated by the transcrip-tion factor CREB is critical for learning and memory. Here we review the features of CREB activation by calcium signals in mammalian cells. In contrast to other transcription factors, its regulation is dependent on an elevation of nuclear calcium concentration, potentially placing this spatially distinct pool of calcium as an important mediator of information storage.© Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 11 (1998), S. 331-343 
    ISSN: 1572-8773
    Keywords: Ca 2+ /calmodulin-dependent protein kinase IV ; calcium ; calmodulin ; CREB ; T lymphocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ca 2+ /calmodulin dependent protein kinase IV (CaMKIV) is a multifunctional, serine-threonine protein kinase that is activated in the presence of increased intracellular calcium ( Ca 2+ ).CaMKIV is a potent medi-ator of Ca 2+ induced gene expression, primarily through its ability to phosphorylate and activate transcrip-tion factors such as CREB. CaMKIV-dependent activation of CREB is a key event in the expression of genes involved in the processes of T-cell activation and neuronal long term potentiation. The focus of this review is to describe the biochemical regulation of CaMKIV and examine how CaMKIV activates tran-scription in response to calcium in both cell and animal models.© Kluwer Academic Publishers
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    Biodegradation 9 (1998), S. 369-379 
    ISSN: 1572-9729
    Keywords: calcium ; fluoranthene fluoranthene ; membrane permeabilization ; polycyclic aromatic hydrocarbons ; Sphingomonas paucimobilis ; surfactant-enhanced biodegradation ; Triton X-100
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Surfactants are known to increase the apparent aqueous solubility of polycyclic aromatic hydrocarbons (PAHs) and may thus be used to enhance the bioavailability and thereby to stimulate the biodegradation of these hydrophobic compounds. However, surfactants may in some cases reduce or inhibit biodegradation because of toxicity to the bacteria. In this study, toxicity of surfactants on Sphingomonas paucimobilis strain EPA505 and the effect on fluoranthene mineralization were investigated using Triton X-100 as model surfactant. The data showed that amendment with 0.48 mM (0.3 g l-1) of Triton X-100 completely inhibited fluoranthene and glucose mineralization and reduced cell culturability by 100% in 24 h. Electron micrographs indicate that Triton X-100 adversely affects the functioning of the cytoplasmic membrane. However, in the presence of 4.13 mM Ca2+-ions, Triton X-100 more than doubled the maximum fluoranthene mineralization rate and cell culturability was reduced by only 10%. In liquid cultures divalent ions, Ca2+ in particular and Mg2+ to a lesser extent, were thus shown to be essential for the surfactant-enhanced biodegradation of fluoranthene. Most likely the Ca2+-ions stabilized the cell membrane, making the cell less sensitive to Triton X-100. This is the first report on a specific factor which is important for successful surfactant-enhanced biodegradation of PAHs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 208 (1998), S. 37-45 
    ISSN: 1432-041X
    Keywords: Key words wingless ; Wnt ; Drosophila ; Brain development ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We have studied the role of the wingless gene in embryonic brain development of Drosophila. wingless is expressed in a large domain in the anlage of the protocerebrum and also transiently in smaller domains in the anlagen of the deutocerebrum and tritocerebrum. Elimination of the wingless gene in null mutants has dramatic effects on the developing protocerebrum; although initially generated, approximately one half of the protocerebrum is deleted in wingless null mutants by apoptotic cell death at late embryonic stages. Using temperature sensitive mutants, a rescue of the mutant phenotype can be achieved by stage-specific expression of functional wingless protein during embryonic stages 9–10. This time period correlates with that of neuroblast specification but preceeds the generation and subsequent loss of protocerebral neurons. Ectopic wingless over-expression in gain-of-function mutants results in dramatically oversized CNS. We conclude that wingless is required for the development of the anterior protocerebral brain region in Drosophila. We propose that an important role of wingless in this part of the developing brain is the determination of neural cell fate.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 207 (1998), S. 535-541 
    ISSN: 1432-041X
    Keywords: Key words Histones ; Oogenesis ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A genomic fragment was cloned from a DNA library constructed from a Drosophila enhancer trap line in which reporter gene expression was observed at the anterior-most tip of the ovaries and testes. This genomic clone was identified as the L-repeat of the Drosophila melanogaster histone gene cluster. Northern blotting and in situ hybridisation to RNA in tissues with individual cDNAs and PCR-generated probes for each histone confirmed that gene expression was greatest at the anterior portion of each ovariole, in the germarium, and was also elevated in a few individual nurse cells and somatic follicle cells within the egg chamber during early developmental stages. Histone H1 and each of the core histones had a similar expression pattern which was correlated to cell division. Maternal stores of histone transcripts were also transported to the mature oocyte from the nurse cells at a later stage of oogenesis (stage 10), when virtually all the nurse cells contained high levels of histone transcripts. The results are consistent with expression of the somatic histone gene cluster during oogenesis as a co-ordinate unit. There does not seem to be a reduced level of somatic type H1 in the germ-line, as is observed in some other species. The relationship between the P[lacZ] expression pattern in the germarium and the overall expression of the histone cluster suggests there are specific regulatory elements for germ-line expression.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 207 (1998), S. 462-470 
    ISSN: 1432-041X
    Keywords: Key words Genetic variation ; Sevenless ; EGF receptor ; Drosophila ; Photoreceptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The signal transduction pathway controlling determination of the identity of the R7 photoreceptor in the Drosophila eye is shown to harbor high levels of naturally occurring genetic variation. The number of ectopic R7 cells induced by the dosage-sensitive Sev S11.1 transgene that encodes a mildly activated form of the Sevenless tyrosine kinase receptor is highly sensitive to the wild-type genetic background. Phenotypes range from complete suppression to massive overproduction of photoreceptors that exceeds reported effects of known single gene modifiers, and are to some extent sex-dependent. Signaling from the dominant gain-of-function Drosophila Epidermal Growth Factor Receptor (DER-Ellipse) mutations is also sensitive to the genetic backgrounds, but there is no correlation with the effects on Sev S11.1 . This implies that different genes and/or alleles modify the two activated receptor genotypes. The evolutionary significance of the existence of high levels of genetic variation in the absence of normal phenotypic variation is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 179 (1998), S. 99-110 
    ISSN: 1573-4919
    Keywords: diaphragm ; oxygen-derived free radicals ; respiratory muscle fatigue ; nitric oxide ; sarcoplasmic reticulum ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract It is now recognized that respiratory muscle fatigue contributes to the development of respiratory failure in some patients with lung disease. This observation has prompted an examination into the mechanisms of development of muscle fatigue, with the understanding that an elucidation of these processes may lead to new therapeutic approaches to the treatment of these patients. A series of recent studies examining this issue have, moreover, discovered that oxygen-derived free radicals generated during strenuous contraction may modulate respiratory muscle contractile function and contribute to the development of muscle fatigue. The data supporting this concept include: (a) direct (e.g. EPR, ESR studies) and indirect (evidence of lipid peroxidation, protein carbonyl formation, glutathione oxidation) evidence that there is heightened free radical production in contracting muscle, (b) evidence that pharmacologic depletion of muscle antioxidant stores increases degree of muscle fatigue present after a period of exercise, and (c) evidence that administration of agents that act as free radical scavengers retard the development muscle fatigue. Free radicals may produce these changes in muscle force generating capacity by interacting with and altering the function of a number of intracellular-biophysical processes (i.e. sarcolemmal action potential propagation, sarcoplasmic reticulum calcium handling, mitochondrial function, contractile protein interactions).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    ISSN: 1573-4919
    Keywords: heart cells ; taurine ; β-alanine ; taurine-Na+ cotransport ; CBDMB ; Na+-Ca2+ exchanger ; calcium ; nucleus ; confocal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Recent studies in heart cells have shown taurine to induce a sustained increase of both intracellular Ca2+ and Na+. These results led us to believe that the increase in Na+ by taurine could be due to Na+ entry through the taurine-Na+ cotransporter which in turn favours transarcolemmal Ca2+ influx through Na+-Ca2+ exchange. Therefore, we investigated the effect of β-alanine, a blocker of the taurine-Na+ cotransporter and low concentrations of CBDMB (a pyrazine derivative, 5-(N-4chlorobenzyl)-2′,4′-dimethylbenzamil), a Na+-Ca2+ exchanger blocker on taurine-induced [Ca]i increase in embryonic chick heart cells. Using Fura-2 Ca2+ imaging and Fluo-3 Ca2+ confocal microscopy techniques, taurine (20 mM) as expected, induced a sustained increase in [Ca]i at both the cytosolic and the nuclear levels. Preexposure to 500 μM of the blocker of the taurine-Na+ cotransporter, β-alanine, prevented the amino acid-induced increase of total [Ca]i. On the other hand, application of β-alanine did not reverse the action of taurine on total [Ca]i. However, low concentrations of the Na+-Ca2+ exchanger blocker, CBDMB, reversed the taurine-induced sustained increase of cytosolic and nuclear free calcium (in presence or absence of β-alanine). Thus, the effect of taurine on [Ca]i in heart cells appears to be due to Na+ entry through the taurine-Na+ cotransporter which in turn favours transarcolemmal Ca2+ influx through the Na+-Ca2+ exchanger.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 180 (1998), S. 53-57 
    ISSN: 1573-4919
    Keywords: diabetes ; cardiomyopathy ; lipids ; lipoprotein lipase ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract It has been established that diabetes results in a cardiomyopathy, and increasing evidence suggests that an altered substrate supply and utilization by cardiac myocytes could be the primary injury in the pathogenesis of this specific heart muscle disease. For example, in diabetes, glucose utilization is insignificant, and energy production is shifted almost exclusively towards β-oxidation of free fatty acids (FFA). FFA's are supplied to cardiac cells from two sources: lipolysis of endogenous cardiac triglyceride (TG) stores, or from exogenous sources in the blood (as free acid bound to albumin or as TG in lipoproteins). The approximate contribution of FFA from exogenous or endogenous sources towards β-oxidation in the diabetic heart is unknown. In an insulin-deficient state, adipose tissue lipolysis is enhanced, resulting in an elevated circulating FFA. In addition, hydrolysis of the augmented myocardial TG stores could also lead to high tissue FFA. Whatever the source of FFA, their increased utilization may have deleterious effects on myocardial function and includes the abnormally high oxygen requirement during FFA metabolism, the intracellular accumulation of potentially toxic intermediates of FFA, a FFA-induced inhibition of glucose oxidation, and severe morphological changes. Therapies that target these metabolic aberrations in the heart during the early stages of diabetes could potentially delay or impede the progression of more permanent sequelae that could ensue from otherwise uncontrolled derangements in cardiac metabolism.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 179 (1998), S. 135-145 
    ISSN: 1573-4919
    Keywords: calcium ; non-lysosomal proteases ; muscle damage ; neutrophils ; muscle regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract It is well established that periods of increased contractile activity result in significant changes in muscle structure and function. Such morphological changes as sarcomeric Z-line disruption and sarcoplasmic reticulum vacuolization are characteristic of exercise-induced muscle injury. While the precise mechanism(s) underlying the perturbations to muscle following exercise remains to be elucidated, it is clear that disturbances in Ca2+ homeostasis and changes in the rate of protein degradation occur. The resulting elevation in intracellular [Ca2+] activates the non-lysosomal cysteine protease, calpain. Because calpain cleaves a variety of protein substrates including cytoskeletal and myofibrillar proteins, calpain-mediated degradation is thought to contribute to the changes in muscle structure and function that occur immediately following exercise. In addition, calpain activation may trigger the adaptation response to muscle injury. The purpose of this paper is to: (i) review the chemistry of the calpain-calpastatin system; (ii) provide evidence for the involvement of the non-lysosomal, calcium-activated neutral protease (calpain) in the response of skeletal muscle protein breakdown to exercise (calpain hypothesis); and (iii) describe the possible involvement of calpain in the inflammatory and regeneration response to exercise.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    ISSN: 1573-4919
    Keywords: aortic cells ; steady state R-type Ca2+ channel ; ET-1 ; insulin ; calcium ; G-protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract In single rabbit aortic smooth muscle cells, and at a concentration known to induce a maximum sustained increase of intracellular Ca2+ via activation of the steady-state voltage dependent R-type Ca2+ channels, endothelin-1 (10-7 M) and insulin (80 μU/ml) were found to induce a sustained increase in cytosolic free Ca2+ ([Ca]i) levels that was significantly attenuated by pre-treatment with either pertussis toxin (PTX), cholera toxin (CTX) or removal of extracellular Ca2+. However, both PTX and CTX failed to inhibit the sustained depolarization-evoked sustained Ca2+ influx and [Ca]i elevation via activation of the R-type Ca2+ channels. Moreover, ET-1 and insulin-evoked sustained increases in Ca2+ influx were not attenuated by the selective PKC inhibitor, bisindolylmaleimide (BIS), or the specific L-type Ca2+ channel blocker, nifedipine, but were completely reversed by the R-type Ca2+ channel blocker, (-) PN 200-110 (isradipine). These data suggest that both insulin and ET-1 activate the nifedipine-insensitive but isradipine-sensitive steady state voltage dependent R-type Ca2+ channels present on rabbit VSMCs and these channels are directly coupled to PTX and CTX sensitive G protein(s).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    ISSN: 1573-4919
    Keywords: hyperosmolality ; hyperglycemia ; calcium ; smooth muscle cells ; diabetes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Hyperglycemia and/or hyperosmolality may disturb calcium homeostasis in vascular smooth muscle cells (SMCs), leading to altered vascular contractility in diabetes. To test this hypothesis, the KCl induced increases in [Ca2+]i in primarily cultured vascular SMCs exposed to different concentrations of glucose were examined. With glucose concentration in solutions kept at 5.5 mM, KCl induced a fast increase in [Ca2+]i which then slowly declined (type 1 response) in 83% of SMCs from non-diabetic rats. In 9% of non-diabetic SMCs KCl induced a slow increase in [Ca2+]i (type 2 response). Interestingly, under the same culture conditions KCl induced type 1 and type 2 responses in 47 and 35% of SMCs from diabetic rats. When SMCs from non-diabetic or diabetic rats were cultured in 36 mM glucose, KCl induced a fast increase in [Ca2+]i which, however, maintained at a high level (type 3 response). The sustained level of [Ca2+]i in the presence of KCl was significantly higher in cells cultured with 36 mM glucose than that in non-diabetic cells cultured with 5.5 mM glucose. Furthermore, the hyperglycemia-induced alterations in calcium mobilization were similarly observed in cells cultured in high concentration of mannitol (30.5 mM) or L-glucose, indicating that hyperosmolality was mainly responsible for the abnormal calcium mobilization in diabetic SMCs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 187 (1998), S. 47-55 
    ISSN: 1573-4919
    Keywords: Mimosa pudica ; apyrase ; arabinogalactan ; calcium ; circular dichroism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Mimosa pudica Linn leaves with pulvini contain unique isoforms (I and II) of apyrase enzyme (EC 3.6.1.5). The activity of isoform I depends on divalent cation Mn2+. This isoform is associated noncovalently with the polysaccharide, containing mainly of galactose and arabinose sugars. The apparent molecular mass of these 2 isoforms are 36 and 34 Kd respectively. The association of the polysaccharide with the isoform I has been found to be Ca2+ dependent which is endogenously present in this isoform. Removal of Ca2+ and polysaccharide from the enzyme (isoform I) leads to an inactivation. The enzyme activity can be restored when both Ca2+ and endogenous polysaccharide fraction were added at an optimal molar ratio of Ca2+:protein of 7:1. The endogenous polysaccharide can be replaced by the standard arabinogalactan. No other sugar or polysaccharide except the arabinogalactan can restore the apyrase activity. Calcium mediates a conformational change in the protein which helps in association of polysaccharide as evidenced from fluorometric and far UV-CD studies to restore the enzymic activity. Neither any interaction of the polysaccharide with the protein is detected in absence of Ca2+ nor the enzyme activity could be recovered under such condition.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 187 (1998), S. 1-10 
    ISSN: 1573-4919
    Keywords: oxidant ; cardiovascular system ; signal transduction ; calcium ; mitogen activated protein kinases ; nuclear transcription factors ; tyrosine kinase ; protein kinase C ; superoxide ; hydrogen peroxide ; ischemia-reperfusion ; atherosclerosis ; phospholipases ; apoptosis ; antioxidant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Although oxidants such as superoxide (O2.-) and hydrogen peroxide (H2O2) play a role in host-mediated destruction of foreign pathogens yet excessive generation of oxidants may lead to a variety of pathological complications in the cardiovascular system. An important mechanism by which oxidants cause dysfunction of the cardiovascular system appears to be due to the increase in intracellular free Ca2+ concentration. Oxidants cause cellular Ca2+ mobilization by modulating activities of a variety of regulators such as Na+/H+ and Na+/Ca2+ exchangers, Na+/K+ ATPase and Ca2+ ATPase and Ca2+ channels that are associated with Ca2+ transport in the plasma membrane and the sarco(endo)plasmic reticular membrane of myocardial cells. Recent research have suggested that the increase in Ca2+ level by oxidants plays a pivotal role in indicing several protein kinases such as protein kinase C, tyrosine kinase and mitogen activated protein kinases. Oxindant-mediated alteration of different signal transduction systems and their interations eventually regulate a variety of pathological conditoins such as atherosclerosis, apoptosis and necrosis in the myocardium
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    ISSN: 1573-4919
    Keywords: diabetes ; Ca2+-Mg2+-ATPase ; calcium ; liver plasma membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The alteration in calcium transport in the liver of rats with streptozocin(STZ)-diabetic state was investigated. STZ (6 mg/100 g body weight) was subcutaneously administered in rats, and 1 or 2 weeks later they were sacrificed by bleeding. STZ administration caused a remarkable elevation of serum glucose concentration. Liver calcium content was significantly increased by STZ administration. Hepatic plasma membrane (Ca2+-Mg2+)-ATPase activity was markedly elevated by STZ administration. This increase was completely abolished by the presence of staurosporine (10-7-10-5 M), an inhibitor of protein kinase C, in the enzyme reaction mixture, suggesting an involvement of protein kinase C signalling. Moreover, the STZ-induced increase in liver plasma membrane (Ca2+-Mg2+)-ATPase activity was significantly raised by the presence of okadaic acid (10-5 and 10-4 M). Meanwhile, the STZ-increased (Ca2+-Mg2+)-ATPase activity was not appreciably altered by the presence of anti-regucalcin IgG in the reaction mixture, indicating that the activatory protein regucalcin does not participate in the elevation of the enzyme activity. The present study demonstrates that STZ-induced diabetes causes the increase in hepatic plasma membrane (Ca2+-Mg2+)-ATPase activity of rats.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 184 (1998), S. 393-400 
    ISSN: 1573-4919
    Keywords: ATP synthase ; phosphorylation potential ; cytosolic pH ; reperfusion damage ; calcium ; free radicals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A short period of ischemia followed by reperfusion produces a state of affairs in which the cells' potential for surviving longer ischemia is enhanced. This is called ischemic preconditioning. The effects of preconditioning are also related to the reperfusion damage which ensues upon tissue oxygenation. The role of the cellular energy state in reperfusion damage remains an enigma, although ischemic preconditioning is known to trigger mechanisms which contribute to the prevention of unnecessary ATP waste. In some species up to 80% of ATP hydrolysis in ischemia can be attributed to mitochondrial F1-F0-ATPase (ATP synthase), and a role for its inhibitor protein (IF1) in ATP preservation has been proposed. Although originally regarded as limited to large animals with a slow heart beat, inhibition by IF1 is probably a universal phenomenon. Coincidentally with ATPase inhibition, the decline in cellular ATP slows down, but even so the difference in ATP concentration between preconditioned and non-conditioned hearts is still small at the final stages of a long ischemia, when the beneficial effect of preconditioning is observable, although the energy state during reperfusion remains low in hearts which do not recover.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    ISSN: 1573-4919
    Keywords: calcium ; Ca2+-ATPase ; DNA fragmentation ; liver nuclei ; liver injury ; carbon tetrachloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The alteration in calcium transport in the liver nuclei of rats orally administered carbon tetrachloride (CCl4) was investigated. Rats received a single oral administration of CCl4(5, 10, and 25%, 1.0ml/100 g body weight), and 5, 24 and 48 h later the animals were sacrificed. The administration of CCl4 (25%) caused a remarkable elevetion of calcium content in the liver tissues and the nuclei of rats. Liver nuclear Ca2+-ATPase activity was markedly decreased by CCl4 (25%) administration. The presence of dibutyryl cyclic AMP(10-4 and 10-3 M) or inositol 1,4,5-trisphosphate (10-6 and 10-5 M) in the enzyme reaction mixture caused a significant decrease in Ca2+-ATPase activity in the liver nuclei obtained from normal rat, while the enzyme activity was significantly increased by calmodulin (1.0 and 2.0 μg/ml). These signaling factor's effects were completely impaired in the liver nuclei obtained from CCl4 (25%)-administered rats. DNA fragmentation in the liver nuclei obtained from CCl4 -administered rats was significantly decreased by the presence of EGTA (2 mM) in the reaction mixture, suggesting that the endogenous calcium activates nuclear DNA fragmentation. The present study demonstrates that calcium transport system in the liver nuclei is impaired by liver injury with CCl4 administration in rats.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    ISSN: 1573-4978
    Keywords: mitochondria ; Drosophila ; sea urchin ; ATP synthase ; embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Complementary DNAs encoding nuclear-coded mitochondrial ATP synthase subunit α of Drosophila melanogaster and Strongylocentrotus purpuratus were obtained by a combination of library screening and redundant PCR. The entire coding sequence of the precursor polypeptide was inferred for both species. Southern blots to genomic DNA indicated that the gene is almost certainly single-copy in both organisms. Northern blots to RNA from staged developmental series showed that ATP synthase subunit α mRNA is represented in the egg, declines in abundance during cleavage, and is replenished by zygotic transcription in both species. However, the extent and timing of these changes differ significantly in the two species studied. Nuclear-coded and mitochondrially encoded ATP synthase genes appear to be temporally co-regulated in Drosophila, but not sea urchin development.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    Springer
    Behavioral ecology and sociobiology 42 (1998), S. 163-169 
    ISSN: 1432-0762
    Keywords: Key words Lek behavior ; Mating ecology ; Ideal free distribution ; Body size ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Male costs and benefits associated with male display size in field populations of an Australian lekking Drosophila species were examined. Results suggested that male mating success increased with display size, since matings appeared to be more common in large displays, and since the probability of males encountering a female increased as displays contained more males. Female encounter probabilities did not increase once about 20 males or more were present on a display. Male size and fighting costs tended to increase with display size. The distribution of males among displays did not follow the ideal free distribution in the sense that each male did not have equal mating opportunity per unit time. Deviation from an ideal free distribution may have been due to female preference for mating in aggregations rather than with solitary males, since in a field experiment females were more willing for mating in an aggregation of five males than with solitary males.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 258 (1998), S. 571-579 
    ISSN: 1617-4623
    Keywords: Key words Tetracycline repressor ; Inducible promoter ; Drosophila ; Aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The “reverse” tetracycline repressor (rtR) binds a specific DNA element, the tetracycline operator (tetO), only in the presence of tetracycline, or derivatives such as doxycycline (dox). Fusion of rtR to the transcriptional activation domain of herpes virus protein VP16 produces a eukaryotic transactivator protein (rtTA). rtTA has previously been shown to allow dox-dependent transcription of transgenes linked to tetO sequences in mammals. To adapt this system to Drosophila, the Actin5C promoter was used to drive constitutive expression of rtTA in transgenic flies. Three reporter constructs, each encoding E. coli β-galactosidase (β-gal), were also introduced into transgenic flies. In one reporter seven tetO sequences were fused to the Adh core promoter. The other two reporter constructs contain seven tetO sequences fused to the hsp70 core promoter. Feeding of transgenic Drosophila containing the rtTA construct and any one of the three reporter constructs with dox caused up to 100-fold induction of β-gal. Dox induced β-gal expression in all tissues, in larvae and in young and senescent adults. Induction of β-gal in adults had no detectable effect on life span. These results suggest the potential usefulness of this system for testing specific genes for effects on Drosophila development and aging.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    ISSN: 1573-5028
    Keywords: calcium ; in situ hybridization ; multigene family ; polyploid ; signal transduction ; Triticum aestivum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Recently, we reported on the characterization of the calmodulin (CaM) gene family in wheat [44]. We classified wheat CaM genes into four subfamilies (SFs) designated SF-1 to SF-4, each representing a series of homoeoallelic loci on the homoeologous chromosomes of the three genomes of common wheat. Here we studied the expression of these wheat CaM genes in the course of wheat development. Northern blot analysis using SF-specific probes revealed differences in SF expression levels in different organs and stages of development. Subsequently, cell-specific expression of CaM SFs was investigated by in situ RNA hybridization. In developing seeds, all CaM SFs showed highest expression in the embryo and less in the aleurone and in the starchy endosperm. In primary roots, all four CaM SFs were expressed in the root cap, meristematic regions and in differentiating cells. During development of the roots, expression gradually decreased. The wheat glutenin gene, which was used as a control throughout our experiments, was found to be expressed in the starchy endosperm but not in the aleurone, embryos or vegetative tissues. In stems, at advanced stages of growth, differences in cell-specific expression of CaM SFs were found. For example, SF-2 was highly expressed in differentiating phloem fibers. Thus, CaM genes in common wheat exhibit a developmentally regulated organ-, tissue-, cell- and SF-specific expression patterns.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 1617-4623
    Keywords: Key words Cytochrome P450 ; Toxin resistance ; Multigene family ; Induction ; Drosophila
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In vertebrates, cytochrome P450s of the CYP2 and CYP3 families play a dominant role in drug metabolism, while in insects members of the CYP6 and CYP28 families have been implicated in metabolism of insecticides and toxic natural plant compounds. A degenerate 3′ RACE strategy resulted in the identification of fifteen novel P450s from an alkaloid-resistant species of Drosophila. The strong (17.4-fold) and highly specific induction of a single gene (CYP4D10) by the toxic isoquinoline alkaloids of a commonly utilized host-plant (saguaro cactus) provides the first indication that members of the CYP4 family in insects may play an important role in the maintenance of specific insect-host plant relationships. Strong barbiturate inducibility of CYP4D10 and two other D. mettleri P450 sequences of the CYP4 family was also observed, suggesting a pattern of xenobiotic responsiveness more similar to those of several vertebrate drug-metabolizing enzymes than to putative vertebrate CYP4 homologs.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    ISSN: 1573-5028
    Keywords: baculovirus ; calcium ; calmodulin ; GABA (γ-aminobutyric acid) ; Sf9 insect cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The nucleotide sequences of cDNAs encoding two isoforms of Arabidopsis glutamate decarboxylase, designated GAD1 (57.1 kDa) and GAD2 (56.1 kDa) and sharing 82% identical amino acid sequences, were determined. The recombinant proteins bound [35S] calmodulin (CaM) in the presence of calcium, and a region of 30–32 amino acids from the C-terminal of each isoform was sufficient for CaM binding when fused to glutathione S-transferase. Full-length GAD1 and GAD2 were expressed in Sf9 insect cells infected with recombinant baculovirus vectors. Recombinant proteins were partially purified by CaM affinity chromatography and were found to exhibit glutamate decarboxylase activity, which was dependent on the presence of Ca2+/CaM at pH 7.3. Southern hybridizations with GAD gene-specific probes suggest that Arabidopsis possesses one gene related to GAD1 and one to GAD2. Northern hybridization and western blot analysis revealed that GAD1 was expressed only in roots and GAD2 in roots, leaves, inflorescence stems and flowers. Our study provides the first evidence for the occurrence of multiple functional Ca2+/CaM-regulated GAD gene products in a single plant, suggesting that regulation of Arabidopsis GAD activity involves modulation of isoform-specific gene expression and stimulation of the catalytic activity of GAD by calcium signalling via CaM.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    ISSN: 1573-5044
    Keywords: calcium ; cobalt ; copper ; magnesium ; sapogenin steroid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The simultaneous effect of calcium, cobalt, copper and magnesium ions and their interactions on growth and sapogenin steroids accumulation in callus cultures of Agave amaniensis was studied by using a central composite second-order rotatable design. The absence of calcium ions in media increased the sapogenin steroid content, while relatively high concentration of magnesium, cobalt and copper ions simultaneously inhibited the sapogenin steroid formation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 199 (1998), S. 23-27 
    ISSN: 1573-5036
    Keywords: aluminium ; calcium ; magnesium ; Picea abies ; root content
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The longterm effect of acid irrigation and liming (dolomitic limestone) on the mineral element content of roots of Norway spruce (Picea abies [L.] Karst.) was investigated in an 80-year-old Norway spruce stand in South Germany (Bavaria). Soil cores of four soil depths (humic layer, 0–10, 10–20 and 20–30 cm) were taken over 2 years (August 1991 and August 1992) from six plots with different treatments (control, normal irrigation, acid irrigation solely or in combination with liming) and living short roots selected and analysed for calcium (Ca), magnesium (Mg), manganese (Mn) and aluminium (Al). On the acid irrigated plot, the Ca and Mg contents of roots were decreased in 1991, but by 1992, 2 years after the irrigation had been terminated, no difference could be found. The Al content of the roots was not increased by acid irrigation but rose with increasing soil depth, regardless of treatment. Liming increased root contents of Ca and Mg and reduced contents of Mn and Al. This effect was especially distinct in the humic layer and decreased with increasing soil depth. Even though the molar Ca/Al-ratio in the roots in the mineral soil was generally low (0.09–0.52), no evidence of Al toxicity could be found. The formation of Al complexes is discussed as a reason for this behaviour.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    ISSN: 1573-5168
    Keywords: cobalt ; calcium ; uptake ; inhibition ; calcium injection ; blockers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Using tracer-uptake studies we investigated whether the branchial uptakeof cobalt occurs via selective, inhibitable, calcium uptake routes.Modulation of the calcium transport system was performed using generalcalcium channel blockers (Cd2+, La3+,Mg2+), a voltage-dependent calcium channel blocker (diltiazem)and an intraperitoneal CaCl2 injection. Adding Cd2+ orMg2+ to thewater or injecting the fish with theCa2+-solution resulted in decreased Co2+ andCa2+ uptake rates. Addition of La3+ reducedCa2+ and Co2+ uptake rates except forCo2+ uptake in the gills. Diltiazem displayed only aninconsistent, concentration-independent blocking of the uptake of bothCo2+ and Ca2+. All inhibitors which inhibitCa2+ uptake also inhibit Co2+ uptake. However, aclear difference in the degree of inhibition of uptake of both elements isobserved. Two possible explanations are suggested (1) Co2+ andCa2+ are both transported through the gills via the sametransport system or (2) the calcium transport system is not the only systeminvolved in the transport of Co2+.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Springer
    Fish physiology and biochemistry 18 (1998), S. 135-147 
    ISSN: 1573-5168
    Keywords: group I phospholipase A2 ; isoforms ; calcium ; hepatopancreas ; marine fish ; Pagrus major
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two phospholipase A2 (PLA2) isoforms, tentatively denoted as DE-1 and DE-2 PLA2s, were purified from the hepatopancreas of red sea bream (Pagrus major) to near homogeneity by sequential column chromatography on S-Sepharose fast flow, DEAE-Sepharose fast flow and butyl-Cellulofine, and by ion-exchange, gel-filtration and reversed-phase HPLC. The purified DE-1 and DE-2 PLA2s both showed a single band with the apparent molecular mass of approx. 13.5 kDa by SDS-polyacrylamide gel electrophoresis, and were found to be both related to group I PLA2 based on the N-terminal amino acid sequences. DE-1 PLA2 had a pH optimum in the alkaline region at around pH 10 and required approximately 10 mM of Ca2+ and 4-10 mM of sodium deoxycholate for its maximal activity, using 2 mM of phosphatidylcholine and phosphatidylethanolamine as substrates. DE-2 PLA2 also had a pH optimum in the alkaline region at around pH 8-9 and required 〉10 mM of Ca2+ and approximately 6 mM of sodium deoxycholate for its maximum activity with 2 mM of phosphatidylcholine as a substrate; its enzymatic activity towards phosphatidylethanolamine was greatly inhibited by the addition of sodium deoxycholate. The results demonstrate that red sea bream hepatopancreas contains two enzymatically distinct group I PLA2 isoforms.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    ISSN: 1573-6857
    Keywords: protein evolution ; Drosophila ; synonymous ; nonsynonymous ; Index of Dispersion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of synonymous and nonsynonymous substitution were investigated for 24 genes in three Drosophila species, D. pseudoobscura, D. subobscura, and D. melanogaster. D. pseudoobscura and D. subobscura, two distantly related members of the obscura clade, differ on average by 0.29 synonymous nucleotide substitutions per site. D. melanogaster differs from the two obscura species by an average of 0.81 synonymous substitutions per site. Using a method developed by Gillespie, we investigated the variance to mean ratio, or Index of Dispersion, R, of substitutions along the three species' branches to test the fundamental prediction of the neutral theory of molecular evolution, E(R) = 1. For nonsynonymous substitutions, the average R, Ra is 1.6, which is not significantly different from the neutral theory prediction. Only 5 of the 24 genes had significantly large Ra valves, and 12 of the genes had Ra estimates of less than one. In contrast, the Index of Dispersion for synonymous substitutions was significantly large for 12 of the 24 genes, with an average of Rs = 4.4, also statistically significant. These findings contrast with results for mammals, which showed overdispersion of nonsynonymous substitutions, but not of synonymous substitutions. Weak selection acting to maintain codon bias in Drosophila, but not in mammals, may be important in explaining the high variance in the rate of synonymous substitutions in this group of organisms.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    ISSN: 1573-6857
    Keywords: Drosophila ; evolution ; sex chromosomes ; Y chromosome degeneration ; Y chromosome mutations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Y chromosome degeneration is characterized by structural changes in the chromosome architecture and expansion of genetic inertness along the Y chromosome. It is generally assumed that the heteromorphic sex chromosome pair has developed from a pair of homologues. Several models have been suggested. We use the unique situation of the secondary sex chromosome pair, neo-Y and neo-X (X2), in Drosophila miranda to analyze molecular mechanisms involved in the evolutionary processes of Y chromosome degeneration. Due to the fusion of one of the autosomes to the Y chromosome (about 2 Mya), a neo-Y chromosome and a neo-X chromosome, designated X2, were formed. Thus, formerly autosomal genes are inherited now on a pair of sex chromosomes in D. miranda. Analyzing DNA sequences from the X2 and neo-Y region, we observed a massive accumulation of DNA insertions on the neo-Y chromosome. From the analysis of several insertion elements, we present compelling evidence that the first step in Y chromosome degeneration is driven by the accumulation of transposable elements, especially retrotransposons. An enrichment of these elements along an evolving Y chromosome could account for the switch from a euchromatic into a heterochromatic chromatin structure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    ISSN: 1573-6830
    Keywords: Growth hormone ; growth hormone releasing hormone ; somatostatin ; neuropeptides ; thyroid hormones ; steroid hormones ; calcium ; acromegaly ; dwarfism ; diabetes ; neuroimmune interactions ; pacemaker activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    ISSN: 1573-6830
    Keywords: substance P ; pain ; signal transduction ; phospholipase C ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. We developed a simple and sensitive peripheral analgesic test in mice. 2. Substance P (SP) given into the planta (i.pl.) of the mouse hind limb produced a flexor response. The flexor response was dependent on SP doses (0.1–100 pmol, i.pl.). When SP (10 pmol) was given every 5 min, there were stable flexor responses. These nociceptive responses were completely abolished by CP-96,345, a neurokinin 1 receptor antagonist. 3. SP-induced responses were also blocked by several signal transduction-related compounds, such as tetrodotoxin, EGTA, and U73122, a selective phospholipase C inhibitor. 4. These findings suggest that SP depolarizes peripheral nerve endings, possibly through inositol trisphosphate (Ins P3)-gated Ca2+ influx, followed by induction of action potentials in the peripheral axons of primary afferent neurons.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Genetica 102-103 (1998), S. 3-19 
    ISSN: 1573-6857
    Keywords: mutation rate ; selection ; self-fertilization ; Y chromosomes ; genetic recombination ; Drosophila ; flowering plants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Most mutations with observable phenotypic effects are deleterious. Studies of Drosophila and inbred plant populations suggest that a new individual may have a mean number of new deleterious mutations that exceeds one-half. Most of these have relatively small homozygous effects and reduce fitness by 1–2% when heterozygous. Several striking features of present-day organisms have apparently evolved in response to the constant input of deleterious alleles by recurrent mutation. For example, the adaptations of hermaphroditic organisms for outcrossing have been widely interpreted in terms of the benefits of avoiding the reduced fitness of inbred progeny, which is partly due to deleterious mutations. Population genetic models of modifiers of the breeding system in the presence of genome-wide deleterious mutation are reviewed and their predictions related to genetic and comparative data. The evolution of degenerate Y chromosomes is a phenomenon that may be caused by the accumulation of deleterious mutations. The population genetic mechanisms that can drive this degeneration are reviewed and their significance assessed in the light of available data.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...