SEARCH · Search PubMed

Results for “salinity tolerance”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources

PubMed2006

[Tolerance of Craspedacusta sowerbyi xinyangensis to the stresses of some ecological factors].

This paper studied the tolerance of Craspedacusta sowerbyi xinyangensis to the stresses of temperature, salinity, and pH from the aspects of its living status, morphology and survival, and measured its oxygen consumption rate and oxygen tolerance at different temperatures. The results indicated that the suitable temperature and pH of C. sowerbyi xinyangensis were 15 degrees C - 25 degrees C and 6.0 - 8.2, respectively. C. sowerbyi xinyangensi had a low tolerance to salinity, and it could only survive for 96 h when the salinity was 2. C. sowerbyi xinyangensi could bear low DO, and its lethal DO was 0.26 mg x L(-1) at 20 degrees C. The average oxygen consumption amount and rate of C. sowerbyi xinyangensi increased with increasing temperature.

Adaptation, Physiological↗

PubMedDate not supplied

Tolerance of soil flagellates to increased NaCl levels.

The ability of heterotrophic flagellates to survive and adapt to increasing salinities was investigated in this study. Whole soil samples were subjected to salinities corresponding to marine conditions and clonal cultures were used to perform growth and adaptation experiments at a wide range of different salinities (0-50 ppm). More morphotypes tolerant to elevated NaCl levels were found in road verge soil that was heavily exposed to de-icing salt than in less exposed soils, though there were fewer tolerant than intolerant morphotypes in all soils examined. Heterotrophic flagellates isolated on a freshwater medium from a non-exposed soil were unable to thrive at salinities above 15 ppt, and showed reduced growth rates even at low salt salinities (1-5 ppt). The findings suggest that heterotrophic soil flagellates are less tolerant to NaCl than their aquatic relatives, possibly due to their long evolutionary history in soil, and support the idea that identical morphospecies may differ considerably with respect to physiology

Adaptation, Physiological↗

PubMed2002

Inhibition of spinal protein kinase Calpha expression by an antisense oligonucleotide attenuates morphine infusion-induced tolerance.

Protein kinase C isoforms including the alpha isozyme have been implicated in morphine tolerance. In the present study, we examined the effect of intrathecal delivery of an antisense oligonucleotide targeting rat protein kinase Calpha mRNA on the expression of spinal protein kinase Calpha isozyme and spinal morphine tolerance. Continuous intrathecal infusion of rats with morphine produced an increase in paw withdrawal threshold to thermal stimulation on day 1, which disappeared by day 5. On day 6, a bolus intrathecal injection of morphine (a probe dose) produced significantly less analgesia in morphine-infused rats than in saline-infused rats, suggesting tolerance. Intrathecal treatment with the protein kinase Calpha antisense concurrent with spinal morphine infusion not only maintained the analgesic effect of morphine during the 5-day infusion, it also significantly increased responsiveness to the probe morphine dose on day 6. In comparison, the missense used in the same treatment paradigm had no effect. The inhibitory effect of protein kinase Calpha antisense on spinal morphine tolerance was dose-dependent, and reversible. Intrathecal treatment with the antisense, but not the missense, in rats decreased expression of spinal protein kinase Calpha mRNA and protein, as revealed by real-time quantitative reverse transcription-polymerase chain reaction and western blots. Expression of the gamma isozyme was not affected by the oligonucleotides. The antisense also attenuated protein kinase C-mediated phosphorylation in spinal cord. These results demonstrate that selective reduction in the expression of the spinal protein kinase Calpha isozyme followed by a decrease of local protein kinase C-mediated phosphorylation will reverse spinal morphine infusion-induced tolerance. This finding is consistent with the view that tolerance produced by morphine infusion is dependent upon an increase in phosphorylation by protein kinase C, and also it emphasizes that the protein kinase Calpha isozyme and its activation in spinal cord may specifically participate in the phenomenon of opiate tolerance.

Animals↗

PubMed2001

Molecular characterization of V-type H(+)-ATPase (B-subunit) in gills of euryhaline crabs and its physiological role in osmoregulatory ion uptake.

The vacuolar-type H(+)-ATPase (V-ATPase) has been implicated in osmoregulatory ion uptake across external epithelia of a growing variety of species adapted to life in fresh water. In the present study, we investigated whether the V-ATPase may also function in a euryhaline species that tolerates brackish water (8 salinity) but not fresh water, the shore crab Carcinus maenas. cDNA coding for the regulatory B-subunit of the V-ATPase was amplified and sequenced from C. maenas gills and partially sequenced from four other crab species. Two isoforms differing in the 3'-untranslated region were found in C. maenas. In this species, the abundance of B-subunit mRNA was greater in the respiratory anterior gills than the ion-transporting posterior gills and was not increased by acclimation to dilute salinity. Immunocytochemical analysis showed that the B-subunit protein is not targeted to the apical membrane but is distributed throughout the cytoplasmic compartment. Physiological studies of isolated perfused gills indicated that the V-ATPase inhibitor bafilomycin had no effect on transepithelial potential difference. Thus, in contrast to the freshwater-tolerant Chinese crab Eriocheir sinensis, in which the V-ATPase appears to play an important osmoregulatory role, the V-ATPase in C. maenas probably functions in acidification of intracellular organelles but not in transbranchial NaCl uptake.

3' Untranslated Regions↗

PubMed2006

Is endogenous opioid system involved in non-opioid analgesics tolerance?

Recent investigations using metamizol and lysine-acetylsalicylate have shown that these non-opioid analgesics produce central anti-nociceptive effects probably through neural substrates that also support the analgesic effects of opiates. The aim of this study was to examine whether a clinically relevant approach, e.g. systemic administration of analgine, ketorolac and xefocam causes tolerance to them, and cross-tolerance to morphine. The experiments were carried out on experimental and control rats with saline by the model of tail-flick reflex to the stimulation of focusing light. Latency increase of this reflex indicates the degree of antinociception. This study of non-opioid analgesic effects on the latency of tail-flick reflex in rats has shown that systemic injections of analgine, ketorolac and xefocam result in significant antinociception as compared with the control group of rats with saline. Repeated administrations of these drugs revealed tolerance to them and cross-tolerance to morphine. Intraperitoneal injections of naloxone did not significantly decrease the morphine analgesic effect in analgine- and ketorolac-tolerant rats, whereas in saline-treated animals morphine analgesic effect was reverted. Taken together the present and previous findings support the notion that the contribution of the CNS, particularly of downstream pain-control structures, to the analgesic effects of NSAIDs involves endogenous opioidergic mechanisms. Thus, obtained data support the suggestion about a close relation between non-opioid tolerance and endogenous opioid system.

Analgesics, Non-Narcotic↗

PubMed1991

Effects of Salinity on Stomatal Conductance, Photosynthetic Capacity, and Carbon Isotope Discrimination of Salt-Tolerant (Gossypium hirsutum L.) and Salt-Sensitive (Phaseolus vulgaris L.) C(3) Non-Halophytes.

The effects of salinity on growth, stomatal conductance, photosynthetic capacity, and carbon isotope discrimination (Delta) of Gossypium hirsutum L. and Phaseolus vulgaris L. were evaluated. Plants were grown at different NaCl concentrations from 10 days old until mature reproductive structures were formed. Plant growth and leaf area development were strongly reduced by salinity, in both cotton and bean. Stomatal conductance also was reduced by salinity. The Delta always declined with increasing external salinity concentration, indicating that stomatal limitation of photosynthesis was increased. In cotton plant dry matter, Delta correlated with the ratio of intercellular to atmospheric CO(2) partial pressures (p(l)/p(a)) calculated by gas exchange. This correlation was not clear in bean plants, although Delta showed a more pronounced salt induced decline in bean than in cotton. Possible effects of heterogeneity of stomatal aperture and consequent overestimation of p(l) as determined from gas exchange could explain these results. Significant differences of Delta between leaf and seed material were observed in cotton and bean. This suggests different patterns of carbon allocation between leaves and seeds. The photon yield of O(2) evolution determined at rate-limiting photosynthetic photon flux density was insensitive to salinity in both species analyzed. The light- and CO(2)-saturated rate of CO(2) uptake and O(2) evolution showed a salt induced decline in both species. Possible explanations of this observation are discussed. O(2) hypersensitivity was observed in salt stressed cotton plants. These results clearly demonstrate that the effect of salinity on assimilation rate was mostly due to the reduction of stomatal conductance, and that calculation of p(l) may be overestimated in salt stressed plants, because of heterogeneity of stomatal aperture over the leaf surface.

Journal Article↗

PubMed2002

Protective role of exogenous polyamines on salinity-stressed rice (Oryza sativa) plants.

Salt-tolerant Pokkali rice plants accumulate higher polyamines (PAs) such as spermidine (Spd) and spermine (Spm) in response to salinity stress, while the sensitive cultivarM-1-48 is unable to maintain high titres of these PAs under similar conditions. The effects of the triamine Spd and the tetramine Spm on physiological and biochemical changes in 12-day-old rice seedlings were investigated during salinity stress to determine whether they could protect the sensitive plants from stress effects. At physiological concentrations Spd and Spm significantly prevented the leakage of electrolytes and amino acids from roots and shoots induced by salinity stress. To different degrees they also prevented chlorophyll loss, inhibition of photochemical reactions of photosynthesis as well as downregulation of chloroplast-encoded genes like psbA, psbB, psbE and rbcL, indicating a positive correlation between salt tolerance and accumulation of higher PAs in rice. The inhibitory effect of salinity stress and its reversal by exogenous PAs were more pronounced in the salt-sensitiveM-1-48 plants than in the tolerant Pokkali plants.

Journal Article↗

PubMed1998

Hypertonic saline test for the investigation of posterior pituitary function.

The hypertonic saline test is a useful technique for distinguishing partial diabetes insipidus from psychogenic polydipsia, and for the diagnosis of complex disorders of osmoreceptor and posterior pituitary function. However, there is little information concerning its use in childhood. The experience of using this test in five children (11 months to 18 years) who presented diagnostic problems is reported. In two patients, in whom water deprivation tests were equivocal or impractical, an inappropriately low antidiuretic hormone (ADH) concentration (< 1 pmol/l) was demonstrated in the presence of an adequate osmotic stimulus (plasma osmolality > 295 mosmol/kg). In two children--one presenting with adipsic hypernatraemia and the other with hyponatraemia complicating desmopressin treatment of partial diabetes insipidus--defects of osmoreceptor function were identified. Confirming a diagnosis of idiopathic syndrome of inappropriate ADH secretion (SIADH) was possible in a patient with no other evidence of pituitary dysfunction. The hypertonic saline test was well tolerated, easy to perform, and diagnostic in all cases.

Adolescent↗

PubMed2003

Photosystem II photochemistry and photosynthetic pigment composition in salt-adapted halophyte Artimisia anethifolia grown under outdoor conditions.

The effects of high salinity (0-400 mmol/L NaCl) on photosystem II (PSII) photochemistry and photosynthetic pigment composition were investigated in the halophyte Artimisia anethifolia grown under outdoor conditions and exposed to full sunlight. High salinity resulted in an inhibition in plant growth and a significant accumulation of sodium and chloride in leaves. However, high salinity induced no effects on the actual PSII efficiency, the efficiency of excitation energy capture by open PSII reaction centres, photochemical quenching, and non-photochemical quenching at midday. High salinity also induced neither changes in the maximum efficiency of PSII photochemistry, the efficiency with which a trapped exciton can move an electron into the electron transport chain further than QA and the quantum yield of electron transport beyond QA, nor changes in absorption, trapping and electron transport fluxes per PSII reaction centre. No significant changes were observed in the levels of neoxanthin, lutein, beta-carotene, violaxanthin, antheraxanthin, and zeaxanthin expressed on a total chlorophyll basis in salt-adapted plants. Our results suggest that Artimisia anethifolia showed high resistance not only to high salinity, but also to photoinhibition even if it was treated with high salinity as high as 400 mmol/L NaCl and exposed to full sunlight. The results indicate that tolerance of PSII to high salinity and photoinhibition can be viewed as an important strategy for Artimisia anethifolia, a halophyte plant, to grow in very high saline soil.

Adaptation, Physiological↗

PubMed1997

N-acetylcysteine administration alters the response to inspiratory loading in oxygen-supplemented rats.

Based on recent studies, it has been suggested that free radicals are elaborated in the respiratory muscles during strenuous contractions and contribute to the development of muscle fatigue. If this theory is correct, then it should be possible to attenuate the development of diaphragm fatigue and/or delay the onset of respiratory failure during loaded breathing by administering a free radical scavenger. The purpose of the present experiment was, therefore, to examine the effect of N-acetylcysteine (NAC), a free radical scavenger and glutathione precursor, on the evolution of respiratory failure in decerebrate unanesthetized rats breathing against a large inspiratory resistive load. We compared the inspiratory volume and pressure generation over time in animals pretreated with either saline or NAC (150 mg/kg) and then loaded until respiratory arrest. After arrest, the diaphragm was excised, and samples were assayed for reduced (GSH) and oxidized glutathione. As a control, we also assessed respiratory function and glutathione concentrations in groups of nonloaded saline- and NAC-treated animals. We found that NAC-treated animals were able to tolerate loading better than the saline-treated group, maintaining higher inspiratory pressures and sustaining higher inspired volumes. Administration of NAC also increased the time that animals could tolerate loading before the development of respiratory arrest. In addition, although saline-treated loaded animals had significant reductions in diaphragmatic GSH levels compared with unloaded controls, the magnitude of this reduction was blunted by NAC administration (i.e., GSH averaged 965 +/- 113, 568 +/- 83, 907 +/- 39, and 784 +/- 61 nmol/g for unloaded-saline, loaded-saline, unloaded-NAC, and loaded-NAC groups, P < 0.05, with the value for the loaded-saline group lower than the values for the two unloaded groups; GSH for the loaded-NAC group was not different, however, from unloaded controls). These data demonstrate that administration of NAC, a free radical scavenger, slows the rate of development of respiratory failure during inspiratory resistive loading.

Acetylcysteine↗

PubMed1985

Morphometric changes of the lung induced by inhaled bacterial endotoxin.

Due to the ubiquitous nature of airborne endotoxin, an understanding of pulmonary alterations which follow inhalation of environmentally realistic concentrations of purified bacteria derived lipopolysaccharide (LPS) is important. Using LPS derived from Enterobacter agglomerans, a bacterium found in cotton and cotton mill dust, aqueous aerosols (effective LPS concentration 4 micrograms/m3) were generated and used to expose either normal hamsters (N = 6) or those rendered endotoxin tolerant by pre-ip injection of 0.1 LD50 LPS. Control groups (normal--N = 6; tolerant--N = 6) received saline aerosol only. At 6 hr after 5-hr aerosol exposure, lungs of all animals were fixed, processed for light and transmission electron microscopy, and subject to qualitative and to multitiered morphometric analysis using standard point counting techniques. Qualitative evaluation of TEM micrographs from LPS aerosolized-nontolerant hamsters showed endothelial alteration (focal disruption, subendothelial space formation, and cytoplasmic blebbing) but volume and number of endothelial cells were not changed indicating only slight, focal endothelial damage. Quantitatively, septal capillary blood space in nontolerant, LPS aerosolized hamsters showed increased Vv of PMNs and platelets. These changes were not seen in tolerant induced-LPS aerosolized hamsters. Independent of tolerization treatment, LPS inhalation led to a decrease in fixed lung volume and an increase in numerical density of endothelial pinocytotic vesicles. It is concluded that the inhalation of realistic, environmental levels of bacterial endotoxin may induce significant changes in distal lung and may be important in the pathogenesis of byssinosis and adult respiratory distress syndrome.

Aerosols↗

PubMed1989

Morphine-induced place conditioning is not confounded by drug-induced alterations in locomotor activity.

The influence of locomotor activity and environmental familiarity upon the reinforcing effects of morphine was examined in an unbiased place preference conditioning procedure. Groups of rats were trained to associate one distinctive environment with morphine and another with saline. One group was made tolerant to the locomotor activity effects of morphine by the SC administration of morphine (5.0 mg/kg/12 hr) for four days prior to conditioning. The other group received injections of saline. Administration of morphine, at doses which decreased locomotor activity, resulted in marked preferences for the drug-associated place in saline-treated rats. In contrast, chronic morphine treatment resulted in tolerance to the sedative effects of morphine and an abolition of the morphine-induced place preference. These results indicate that in the place conditioning procedure, measures of reinforcement are not confounded by drug-induced increases in activity.

Animals↗

PubMed1999

Catecholaminergic activity and 3',5'-cyclic adenosine monophosphate concentrations in the right ventricle after acute and chronic morphine administration in the rat.

We have examined possible regulation of norepinephrine and dopamine concentrations and turnover in the right ventricle of the rat after acute administration of saline i.p. or morphine 30 mg kg-1 i.p. to placebo (naïve) or morphine (tolerant) pretreated rats. We also assessed concentrations of 3',5'-cyclic adenosine monophosphate (cAMP) in the right ventricle after the same treatments. Concentrations of catecholamines and their metabolites in the heart were measured by high-pressure liquid chromatography with electrochemical detection (HPLC/DE). Concentrations of cAMP in the heart were measured by radioimmunoassay (RIA). Administration of morphine to naïve rats did not modify concentrations of norepinephrine (NE), normetanephrine (NMN) or NMN/NE ratio in the right ventricle. However, dopamine concentrations increased whereas dopamine turnover decreased. In addition, cAMP concentrations decreased after acute administration morphine to naïve rats. In rats pretreated with morphine chronically, there was an increase in norepinephrine concentrations with no change in normetanephrine concentrations or norepinephrine turnover after acute injection of morphine. In contrast, dopamine turnover increased in the tolerant groups after acute injection of saline or morphine compared with the nave group given morphine, indicating that tolerance develops to the acute effects of the opioid. Concentrations of cAMP increased after chronic morphine administration. Our results demonstrate that chronic morphine pretreatment leads to up-regulation of the cAMP system in the heart and suggest that this up-regulation may be involved in the cellular mechanisms implicated in the adaptive changes of dopaminergic neurones in the heart observed during chronic treatment with morphine.

Analgesics, Opioid↗

PubMed1996

Expression of a Late Embryogenesis Abundant Protein Gene, HVA1, from Barley Confers Tolerance to Water Deficit and Salt Stress in Transgenic Rice.

A late embryogenesis abundant (LEA) protein gene, HVA1, from barley (Hordeum vulgare L.) was introduced into rice suspension cells using the Biolistic-mediated transformation method, and a large number of independent transgenic rice (Oryza sativa L.) plants were generated. Expression of the barley HVA1 gene regulated by the rice actin 1 gene promoter led to high-level, constitutive accumulation of the HVA1 protein in both leaves and roots of transgenic rice plants. Second-generation transgenic rice plants showed significantly increased tolerance to water deficit and salinity. Transgenic rice plants maintained higher growth rates than nontransformed control plants under stress conditions. The increased tolerance was also reflected by delayed development of damage symptoms caused by stress and by improved recovery upon the removal of stress conditions. We also found that the extent of increased stress tolerance correlated with the level of the HVA1 protein accumulated in the transgenic rice plants. Using a transgenic approach, this study provides direct evidence supporting the hypothesis that LEA proteins play an important role in the protection of plants under water-or salt-stress conditions. Thus, LEA genes hold considerable potential for use as molecular tools for genetic crop improvement toward stress tolerance.

Journal Article↗

PubMed2004

Transcriptome changes in foxtail millet genotypes at high salinity: identification and characterization of a PHGPX gene specifically upregulated by NaCl in a salt-tolerant line.

Using a macro array filter with 711 cDNA inserts representing 620 unigenes selected from a barley EST collection, we identified transcripts differentially expressed in salt (NaCl)-treated tolerant (cv. Prasad) and sensitive (cv. Lepakshi) seedlings of foxtail millet (Setaria italica L.). Transcripts of hydrogen peroxide scavenging enzymes such as phospholipid hydroperoxide glutathione peroxidase (PHGPX), ascorbate peroxidase (APX) and catalase 1 (CAT1) in addition to some genes of cellular metabolism were found to be especially up-regulated at high salinity in the tolerant line. To analyse this process at the protein level we examined protein expression patterns under various stress conditions. A 25 kD protein with a pI of 4.8 was found to be induced prominently under high salt concentrations (250 mmol/L). This salt-induced 25 kD protein has been purified and identified by peptide sequencing as PHGPX protein. The increase of the PHGPX protein level under salt stress in the tolerant line parallels the PHGPX mRNA results of array analysis but was more pronounced. We cloned and characterized the foxtail millet PHGPX cDNA, which shows 85% and 95% homology at the DNA and protein level, respectively, to one stress-induced member of the small barley PHGPX gene family encoding non-selenium glutathione peroxidases. As shown by Southern blot analysis, a small family of PHGPX genes exists in foxtail millet, too. The specific expression pattern of the PHGPX gene in salt-induced tolerant millet seedlings suggests that its product plays an important role in the defense reaction against salt-induced oxidative damage and that the characterized glutathione peroxidase is one of the components conferring resistance against salt to the tolerant foxtail millet cultivar.

Adaptation, Physiological↗

PubMed1997

Characterization of neonatal rat fentanyl tolerance and dependence.

Fentanyl and morphine are administered to human neonates and infants to provide analgesia and sedation during painful and stressful procedures. These opioids have often been shown to produce tolerance and dependence during continuous intravenous infusion. In neonatal animals, morphine produces tolerance and dependence, yet little is known about fentanyl. This report describes the first model for studying opioid tolerance and dependence in neonatal animals with use of osmotic minipumps. Postnatal day 6 rat pups were anesthetized and then remained naive or were surgically implanted subcutaneously with Alzet osmotic minipumps containing either saline or fentanyl (100 microg/kg/hr). Tolerance and dependence were assessed 72 hr after implantation. The ED50 values for fentanyl antinociception in the tail-flick test were not different between naive and saline pump-implanted animals. However, the fentanyl pump-implanted animals were tolerant to fentanyl. The tolerance observed was not the result of gender, developmental changes, fentanyl distribution or changes in fentanyl metabolism. These results indicate that continuous administration of fentanyl via osmotic minipump can render normal neonatal rats tolerant and physically dependent on fentanyl in 72 hr. Withdrawal precipitated by naloxone (5 mg/kg s.c.) in the fentanyl pump-implanted animals was characterized by increased spontaneous activity, micturition/defecation, wall climbing, abdominal stretching, tremors, scream on touch and spontaneous vocalization. This new model may provide a tool for studying the long-term consequences of neonatal opioid exposure in juvenile and adult animals.

Age Factors↗

PubMed2000

Genomic approaches to plant stress tolerance.

Past efforts to improve plant tolerance to drought, high salinity and low-temperature through breeding and genetic engineering have had limited success owing to the genetic complexity of stress responses. Progress is now anticipated through comparative genomics studies of an evolutionarily diverse set of model organisms, and through the use of techniques such as high-throughput analysis of expressed sequence tags, large-scale parallel analysis of gene expression, targeted or random mutagenesis, and gain-of-function or mutant complementation. The discovery of novel genes, determination of their expression patterns in response to abiotic stress, and an improved understanding of their roles in stress adaptation (obtained by the use of functional genomics) will provide the basis of effective engineering strategies leading to greater stress tolerance.

Disasters↗

PubMed1992

Tolerance to the anticonvulsant effects of carbamazepine, diazepam, and sodium valproate in kindled rats.

We assessed the development of tolerance to the anticonvulsant effects of carbamazepine (CBZ), diazepam (DZP), and sodium valproate (VPA) on convulsions elicited by amygdala stimulation in kindled rats in three similar experiments. In each experiment, amygdala-kindled rats were assigned to a drug group or to a corresponding vehicle control group. The rats in the three drug groups received a total of 10 bidaily (one every 48 h) IP injections of CBZ (70 mg/kg), DZP (2 mg/kg) or VPA (250 mg/kg) at a dose that initially blocked the forelimb clonus elicited by an amygdala stimulation (400 microA, 60 Hz, 1 s) administered 1 h after the injection. The rats in the three vehicle control groups were similarly treated except that they received injections of the saline vehicle. The drug tolerance test occurred 48 h after the final tolerance-development trial; the rats from each drug group and the corresponding vehicle control group received an injection of the appropriate drug followed 1 h later by the administration of a convulsive stimulation. The drug tolerance test revealed almost total tolerance in each of the three drug groups but no tolerance in any of the three vehicle control groups. Such large tolerance effects are inconsistent with the less dramatic effects reported in previous studies; possible reasons for this inconsistency were considered.

Amygdala↗