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Kisan B. Jadhav Padmanabhan Sharda Rajini 《Journal of biochemical and molecular toxicology》2009,23(1):9-17
The primary objective of this study was to examine a possible correlation among the three endpoints of toxicity, namely, stress gene expression (hsp16), feeding, and acetylcholinesterase (AChE) activity in transgenic C. elegans (hsp16‐lacZ) exposed to sublethal concentrations of dichlorvos, an organophosphorus insecticide. Worms exposed to dichlorvos (at 5, 40, and 80 μM) exhibited a concentration‐dependent inhibition in feeding with total cessation in feeding occurring beyond 4 h of exposure. Concomitantly, marked and dose‐dependent inhibition (69%–90%) of AChE was also evident after 4 h of exposure. Induction of heat shock protein (Hsp) was evident after 4 h of exposure (as seen from quantitative analysis), although maximum expression of Hsp was evident only after 24 h of exposure (as evident from qualitative analysis). Interestingly, the Hsp induction was restricted only to the pharyngeal region. Significant correlation was discernible between the three evaluated end points suggesting their possible interrelated role in the physiological dysfunctions evoked by sublethal concentrations of dichlorvos. © 2009 Wiley Periodicals, Inc. J Biochem Mol Toxicol 23:9–17, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jbt.20258 相似文献
2.
Rui Xie Xiao Dong Chase Wong Volker Vallon Bo Tang Jun Sun Shiming Yang Hui Dong 《The Journal of biological chemistry》2014,289(50):34642-34653
Epithelial ion transport is mainly under the control of intracellular cAMP and Ca2+ signaling. Although the molecular mechanisms of cAMP-induced epithelial ion secretion are well defined, those induced by Ca2+ signaling remain poorly understood. Because calcium-sensing receptor (CaSR) activation results in an increase in cytosolic Ca2+ ([Ca2+]cyt) but a decrease in cAMP levels, it is a suitable receptor for elucidating the mechanisms of [Ca2+]cyt-mediated epithelial ion transport and duodenal bicarbonate secretion (DBS). CaSR proteins have been detected in mouse duodenal mucosae and human intestinal epithelial cells. Spermine and Gd3+, two CaSR activators, markedly stimulated DBS without altering duodenal short circuit currents in wild-type mice but did not affect DBS and duodenal short circuit currents in cystic fibrosis transmembrane conductance regulator (CFTR) knockout mice. Clotrimazole, a selective blocker of intermediate conductance Ca2+-activated K+ channels but not chromanol 293B, a selective blocker of cAMP-activated K+ channels (KCNQ1), significantly inhibited CaSR activator-induced DBS, which was similar in wild-type and KCNQ1 knockout mice. HCO3− fluxes across epithelial cells were activated by a CFTR activator, but blocked by a CFTR inhibitor. CaSR activators induced HCO3− fluxes, which were inhibited by a receptor-operated channel (ROC) blocker. Moreover, CaSR activators dose-dependently raised cellular [Ca2+]cyt, which was abolished in Ca2+-free solutions and inhibited markedly by selective CaSR antagonist calhex 231, and ROC blocker in both animal and human intestinal epithelial cells. Taken together, CaSR activation triggers Ca2+-dependent DBS, likely through the ROC, intermediate conductance Ca2+-activated K+ channels, and CFTR channels. This study not only reveals that [Ca2+]cyt signaling is critical to modulate DBS but also provides novel insights into the molecular mechanisms of CaSR-mediated Ca2+-induced DBS. 相似文献
3.
Dalal M. Aljedani 《Saudi Journal of Biological Sciences》2022,29(3):1477-1486
Honey bees are important for ecological health, biodiversity preservation, and crop output. Antimicrobials, like Tetracyclines, are commonly used in agriculture, medicine, and beekeeping, bees might be exposed to Tetracycline residues in the environment either directly or indirectly. This study aimed to determine the effect of antibiotic treatment (Tetracycline) effect on the Bio-efficiency of the larvae honey bee (Apis mellifera jemenatica), when larvae honeybee workers were exposed to different concentrations of it, to see how long they survived after being exposed to it and affected this antibiotic to the histological structure of the midgut. The results demonstrated that the concentration (LC50 = 125.25 μg/ml) of antibiotics Tetracycline leads to kills half of the individuals. Our data indicate that the high concentrations of Tetracycline have a significant effect on the histological composition of the cells of the midgut of honeybee larvae. Antibiotic exposure can negatively impact the health of honey bees, especially Tetracycline because it is the most used antibiotic in apiculture. 相似文献
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A screen-house experiment with 0, 25, 50 and 75 ppm S was conducted to study the effect of S on the yield and, Mn, Cu, Fe and Mo concentrations of berseem (Trifolium alexandrinum) at three stages of growth in a normal and reclaimed soil. Higher levels of S decreased the yield in both the soils. Yield in normal soil was much higher than in reclaimed soil. Application of S increased Cu, Mn, and Fe concentrations in all cuts in both soils. Molybdenum concentration was lowered following S application in both the soils in all the cuts. Molybdenum content increased with the stage of plant growth. 相似文献
5.
Growth Inhibition Occurs Independently of Cell Mortality in Tomato (Solanum lycopersicum) Exposed to High Cadmium Concentrations 总被引:1,自引:0,他引:1
In order to analyze the adaptation potential of tomato shoots to a sudden increase in Cd concentration, tomato plants (Solanum lycopersicum L. var. Ailsa Craig) were exposed under controlled environmental conditions to a high dose of this heavy metal (250 μM CdCl2>) in nutrient solution for 7 and 14 d. Both root and shoot growth was completely inhibited but all plants remained alive until the end of the treatment. Cell viability remained unaffected but the activity of the mitochondrial alternative pathway was stimulated by Cd stress at the expense of the cytochrome pathway. Cadmium concentration was higher in roots than in shoots and a decrease In the rate of net Cd translocation was noticed during the second week of stress. Cadmium decreased both leaf conductance (g1>) and chlorophyll concentration. However, the effect on net CO2 assimilation remained limited and soluble sugars accumulated in leaves. Photochemical efficiency of PSll (FvlFm) was not affected despite a decrease in the number of reaction centers and an inhibition of electron transfer to acceptors of PSII. It is concluded that tomato shoot may sustain short term exposure to high doses of cadmium despite growth inhibition. This property implies several physiological strategies linked to both avoidance and tolerance mechanisms. 相似文献
6.
Jiménez S Ollat N Deborde C Maucourt M Rellán-Álvarez R Moreno MÁ Gogorcena Y 《Journal of plant physiology》2011,168(5):415-423
Iron deficiency induces several responses to iron shortage in plants. Metabolic changes occur to sustain the increased iron uptake capacity of Fe-deficient plants. We evaluated the metabolic changes of three Prunus rootstocks submitted to iron chlorosis and their different responses for tolerance using measurements of metabolites and enzymatic activities. The more tolerant rootstocks Adesoto (Prunus insititia) and GF 677 (Prunus amygdalus × Prunus persica), and the more sensitive Barrier (P. persica × Prunus davidiana) were grown hydroponically in iron-sufficient and -deficient conditions over two weeks. Sugar, organic and amino acid concentrations of root tips were determined after two weeks of iron shortage by proton nuclear magnetic resonance spectroscopy of extracts. Complementary analyses of organic acids were performed by liquid chromatography coupled to mass spectrometry. The major soluble sugars found were glucose and sucrose. The major organic acids were malic and citric acids, and the major amino acid was asparagine. Iron deficiency increased root sucrose, total organic and amino acid concentrations and phosphoenolpyruvate carboxylase activity. After two weeks of iron deficiency, the malic, citric and succinic acid concentrations increased in the three rootstocks, although no significant differences were found among genotypes with different tolerance to iron chlorosis. The tolerant rootstock Adesoto showed higher total organic and amino acid concentrations. In contrast, the susceptible rootstock Barrier showed lower total amino acid concentration and phosphoenolpyruvate carboxylase activity values. These results suggest that the induction of this enzyme activity under iron deficiency, as previously shown in herbaceous plants, indicates the tolerance level of rootstocks to iron chlorosis. The analysis of other metabolic parameters, such as organic and amino acid concentrations, provides complementary information for selection of genotypes tolerant to iron chlorosis. 相似文献
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Seven small artificial lakes in West Virginia were sampled in the spring and fall. Water taken during these isothermal periods was used for the EPA Algal Assay with Selenastrum capricornutum as the test alga. In all cases the limiting nutrient was phosphorus. However in every case the water was fertile enough for the alga to grow well without the addition of nutrients. Each lake was sampled several times during the summer and nutrient analysis and chlorophyll concentrations indicated that each lake is probably eutrophic. These conclusions were borne out by the algal assays. The assays also indicated that there were probably no toxic elements in any of the seven lakes. 相似文献
8.
Summary This report presents the results of taphofacies analyses of shelly cheniers (mollusk-dominated lag-concentrations) from the
tidal flats of northeastern Baja California, Mexico. The three generations of moderm (formed during last 70 years), submodem
(younger than 1,500 BP), and subfossil (5,000–2,000 BP) cheniers can be distinguished by their position relative to the shoreline,
their topography, and the radiocarbon-age of their shells. The generations differ in the duration and complexity of their
taphonomic history. Sixty-one samples from nine localities were collected to test the utility of the taphofacies approach
for studying chenier-type shell deposits. The three chenier generations, although all dominated by the bivalve molluskMulinia coloradoensis, differ significantly in their taxonomic composition due to taphonomic and/or biologic factors. The taphofacies analysis
included 4,334 specimens ofM. coloradoensis described by nine taphonomic variables. Univariate analysis of those variables indicated that the shells that accumulated
in the cheniers are little-affected by biological processes (bioerosion, encrustation), and moderately affected by physical
processes (fragmetation, cracking, peeling, edge preservation). Only the luster features of shells (external luster, internal
luster, and internal features) vary substantially and consistently with chenier age —a result of subaerial weathering. Multivariate
taphofacies analysis discriminates the three generations of cheniers even when the poorly preservable luster variables are
excluded from the analysis. This suggests that taphofacies discrimination is possible for fossil cheniers. The shells collected
from the chenier surface have substantially poorer preservation than shells from the subsurface, indicating that taphonomic
degradation in the chenier plain environment is a surface phenomenon. Chenier plain shelly assemblages are taphonomically
distinct from assemblages formed in other marine environments: they have a very low frequency of macroscopically recognizable
bioerosion and encrustation. The existence of preservable taphonomic differences between the cheniers that differ in their
age (i.e., duration of preburial history), suggests that fossil lag concentrations may be useful in detecting incompleteness
gradients along stratigraphic boundaries. A ‘taphonomic clock’—a correlation between a ‘time-sincedeath’ and shell preservation—was
found only for luster features, taphonomic attributes that are unlikely to be preserved in the fossil record. 相似文献
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