SEARCH · Search PubMed

Results for “ALKALIES”

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 199 records · Page 11Linked to original sources

PubMed1988

Enhancement of the detection of alkali-resistant phosphoproteins in polyacrylamide gels.

Following their separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, labeled proteins obtained from cultured canine prostatic epithelial cells incubated with [35S]-methionine and [32P]phosphate were subjected to alkali treatment, a method that is currently used to detect phosphotyrosine-containing proteins. Significant amounts of 35S-labeled material were lost during the alkali treatment. The crosslinking of proteins within the gels by glutaraldehyde treatment eliminated protein losses and did not alter the efficiency of phosphoester bond hydrolysis by alkali treatment. Consequently, the time required to detect alkali-resistant phosphoproteins by autoradiography was greatly reduced. Prostatic phosphoproteins were also shown to contain phosphotyrosine, indicating the presence of tyrosine protein kinase activity in these proliferating epithelial cells.

Alkalies↗

PubMed1994

Alkali-labile sites are prevalent in kidney tissue DNA.

Inherent DNA damage in the form of single strand breaks and alkali labile sites is generated by essential intracellular processes, such as DNA replication and repair. Utilizing the in situ DNA unwinding assay and the comet assay (single cell gel), we have observed high levels of alkali induced DNA strand breaks in cells isolated from mouse kidney tissue homogenate. Kidney cell DNA demonstrated a 7.4 x increase in nucleoid expansion and a 7 x increase in comet length compared to negative control cells (thymocytes and splenocytes) in the two assay systems, comparable to epididymal sperm cells which have previously been demonstrated to contain abundant alkali-labile sites. These results argue for the existence of prevalent alkali-labile sites in kidney cell DNA.

Alkalies↗

PubMed2006

Alkali pH directly activates ATP-sensitive K+ channels and inhibits insulin secretion in beta-cells.

Glucose stimulation of pancreatic beta-cells is reported to lead to sustained alkalization, while extracellular application of weak bases is reported to inhibit electrical activity and decrease insulin secretion. We hypothesize that beta-cell K(ATP) channel activity is modulated by alkaline pH. Using the excised patch-clamp technique, we demonstrate a direct stimulatory action of alkali pH on recombinant SUR1/Kir6.2 channels due to increased open probability. Bath application of alkali pH similarly activates native islet beta-cell K(ATP) channels, leading to an inhibition of action potentials, and hyperpolarization of membrane potential. In situ pancreatic perfusion confirms that these cellular effects of alkali pH are observable at a functional level, resulting in decreases in both phase 1 and phase 2 glucose-stimulated insulin secretion. Our data are the first to report a stimulatory effect of a range of alkali pH on K(ATP) channel activity and link this to downstream effects on islet beta-cell function.

ATP-Binding Cassette Transporters↗

PubMed2005

Optical absorption and photoluminescence properties of Er3+ doped mixed alkali borate glasses.

An investigations of the optical absorption and fluorescence spectra of 0.2 mol% Er2O3 in mixed alkali borate glasses of the type 67.8B2O3 x xLi2O(32-x)Na2O, 67.8B2O3 x xLi2O(32-x)K2O and 67.8B2O3 x xNa2O(32-x)K2O (where x = 8, 12, 16, 20 and 24) are presented. The glasses were obtained by quenching melts consisting of H3BO3, Li2CO3, Na2CO3, K2CO3 and Er2O3 (950-1100 degrees C, 1.5-2 h) between two brass plates. Spectroscopic parameters like Racah (E1, E2 and E3), spin-orbit (xi(4f)) and configuration interaction (alpha) parameters are deduced as function of x. Using Judd-Ofelt theory, Judd-Ofelt intensity parameters (omega2, omega4 and omega6) are obtained. Radiative and non-radiative transition rates (A(T) and W(MPR)), radiative lifetimes (tauR), branching ratios (beta) and integrated absorption cross-sections (sigma) have been computed for certain excited states of Er3+ in these mixed alkali borate glasses. Emission spectra have been studied for all the three Er3+ doped mixed alkali borate glasses. The present paper throws light on the trends observed in the intensity parameters, radiative lifetimes, branching ratios and emission cross-sections as a function of x in these borate glasses, keeping in view the effect of mixed alkalies in borate glasses.

Absorption↗

PubMed2001

Analysis of alkali-lignin in a paper mill effluent decolourised with two Streptomyces strains by gas chromatography-mass spectrometry after cupric oxide degradation.

Alkali-lignin samples obtained from an untreated paper mill effluent and from the effluent decolourised by the strains Streptomyces avermitilis CECT 3339 and Streptomyces scabies UAH 51 were analysed by gas chromatography-mass spectrometry (GC-MS) after cupric oxide degradation. The analysis of the depolymerisation products of the alkali-lignin from the decolourised effluents showed a strain specific modification of the aromatic moiety of the alkali-lignin. Moreover, both strains were able to breakdown the aryl-alkyl ether linkages between the cinnamic acids and the lignin. Finally, GC-MS analysis showed that both strains oxidised the alkali-lignin regardless of its initial degree of oxidation.

Alkalies↗

PubMed2001

High frequency of constitutive alkali-labile sites in mouse major satellite DNA, detected by DNA breakage detection-fluorescence in situ hybridization.

DNA breakage detection-fluorescence in situ hybridization (DBD-FISH) is a new procedure for detecting and quantifying DNA breaks and alkali-labile sites in single cells. Cells trapped within an agarose matrix are deproteinized and treated with an alkaline unwinding solution that transforms DNA breaks and alkali-labile sites into single-strand DNA (ssDNA) motifs starting from the end of the break. These ssDNA motifs are susceptible to being hybridized with whole genome or specific DNA probes, and detected using current FISH procedures. As DNA breaks increase in a target region, more ssDNA is produced and more DNA probe hybridizes, thus increasing the FISH signal, which may be captured and analyzed using a digital image analysis system. This increase can be reflected in the surface area, mean and whole fluorescence intensity of the signal. When intact mouse splenocytes were processed with this technique using a whole genome probe, a very strong background signal was evident when compared with human blood leukocytes. In fact, when using 0.03M NaOH as the alkaline unwinding solution at 22 degrees C for 2.5min, the whole fluorescence intensity from mice cells was 50 times higher than that from human cells, thus suggesting the existence of a high frequency of constitutive alkali-labile sites in the DNA from mouse cells. Furthermore, when alkaline unwound mouse cells were simultaneously hybridized with the whole genome probe (FITC-revealed, green) and a major satellite DNA probe (Cy-3-labeled, red) both signals appeared co-localized. This result demonstrates that the high frequency of constitutive alkali-labile sites detected in the mouse genome is mainly located in the major satellite DNA sequences, resembling the findings from human 5bp classical satellite DNA sequences.

Alkalies↗

PubMed2001

Concentration of 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) in urine and alkali-hydrolyzed urine after consumption of charbroiled beef.

Heterocyclic amines (HAs) and polycyclic aromatic hydrocarbons are carcinogenic products formed during the cooking of meat at moderate to high temperatures. We have previously shown that the urinary concentration of 1-hydroxypyrene-glucuronide, a metabolite of pyrene, increased significantly in ten subjects who had ingested charbroiled ground beef. We now report the time course and interindividual variation of 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP) concentration in the urine samples from these ten subjects. PhIP concentration was determined in both untreated and alkali-hydrolyzed urine to obtain estimates of the proportion of conjugated PhIP metabolites in each subject. PhIP was measured by gas chromatography-negative ion chemical ionization-mass spectrometry after derivatization with pentafluorobenzyl bromide. Ten healthy non-smoking males consumed identical amounts of broiled beef on five consecutive days. The morning after the first day of broiled beef consumption, urinary concentration of PhIP increased 14-38 fold above mean pre-feed concentration of PhIP in individual alkali-hydrolyzed urine samples. Following cessation of broiled beef consumption, urinary PhIP concentration declined to near pre-feed levels within 48-72 hrs. The ratio of total alkali-labile PhIP metabolites to unmetabolized PhIP varied by about 2.7-fold among subjects, ranging from 18:1 to 48:1, suggesting that interindividual differences in PhIP metabolism occur and can be detected by this method. This study of urinary PhIP following ingestion of meat cooked by charbroiling, that contains both HAs and polycyclic aromatic hydrocarbons, extends previous studies of ingestion of pan-fried meat that contains primarily HAs. The results indicate that significant amounts of PhIP are bioavailable from ingestion of charbroiled ground beef and that measurement of proportions of alkali-labile PhIP metabolites and parent PhIP in human urine may yield information on individual metabolism of ingested PhIP.

Adult↗

PubMed2003

Identification and characterization of an intermediate in the alkali degradation of (6-4) photoproduct-containing DNA.

The (6-4) photoproduct formed by ultraviolet light is known as an alkali-labile DNA lesion. Strand breaks occur at (6-4) photoproducts when UV-irradiated DNA is treated with hot alkali. We have analyzed the degradation reaction of this photoproduct under alkaline conditions using synthetic oligonucleotides. A tetramer, d(GT(6-4)TC), was prepared, and its degradation in 50 mm KOH at 60 degrees C was monitored by high performance liquid chromatography. A single peak with a UV absorption spectrum similar to that of the starting material was detected after the reaction, and this compound was regarded as an intermediate before the strand break. The formation of this intermediate was compared with intermediates from the degradation of other alkali-labile lesions such as the abasic site, thymine glycol, and 5,6-dihydrothymine. The results strongly suggested that the first step of the alkali degradation of the (6-4) photoproduct was the hydrolysis between the N3 and C4 positions of the 5'-pyrimidine component. Analyses by NMR spectroscopy and mass spectrometry supported the chemical structure of this product. Assays of the complex formation with XPC.HR23B and the translesion synthesis by DNA polymerase eta revealed that the biochemical properties are indistinguishable between the intact and hydrolyzed photoproducts.

Alkalies↗

PubMed2005

Effect of alkali treatment on properties of native shellac and stability of hydrolyzed shellac.

The objective of this study was to investigate the effect of alkali treatment on properties of shellac. The native shellac was treated with sodium hydroxide for 15, 30, and 60 min to obtain hydrolyzed shellac. All types of shellac, namely native and hydrolyzed shellac at various times of treatment, were then prepared in films as free acid and ammonium salt forms by using ethanol and ammonium hydroxide solution, respectively. The results showed that alkali treatment caused an increase in acid value and a decrease in ester value. This is due to higher free carboxylic and hydroxyl groups caused by ester bond breaking. The longer the alkali treatment the higher impact of bond breaking, therefore, causing an increase in acid value, solubility at pH 7, strain, a decrease in ester value, water vapor permeability coefficient, and stress. The films were then kept at 40 degrees C, 75% RH for a period of three months. The aging effect led to an esterification of free carboxylic and hydroxyl groups, resulting in the significant change of acid value, ester value, and insoluble solid for both native and hydrolyzed shellac films in acid form. On the other hand, all types of shellac films in ammonium salt form exhibited a reasonable stability in physicochemical and mechanical properties as all films were protected from the esterification due to the formation of ammonium salt at the carboxylic binding site. It could be concluded that alkali treatment could produce hydrolyzed shellac with higher solubility in the intestine, the stability was yet in dilemma unless the shellac was in an ammonium salt form. The result obtained could, thus, provide a guideline in the use of shellac.

Alkalies↗

PubMed1966

Stimulation of the salt receptor of the blowfly. III. The alkali halides.

Application of solutions of each of the alkali halides to the tip of a labellar sensillum of the blowfly elicited a repetitive neural discharge from the salt receptor. The records were qualitatively similar to those for NaCl. For each of the alkali chlorides and sodium halides, the shapes of the curves of the response of the salt receptor as a function of concentration were similar to that for NaCl. The alkali halides exhibited a regular pattern of relative stimulating effectiveness for the salt receptor. The effectiveness of the anions increased monotonically with atomic number. The effectiveness of the cations was greatest for potassium and declined as the atomic number was increased or decreased. This hierarchy for stimulating effectiveness was maintained at all tested molarities. The response to a mixture of two salts appeared to be an average of those to the single salts at concentrations equal to the total concentration of the mixture. Cross-adaptation was observed between the alkali halides. The results indicate that an explanation of stimulation of the salt receptor must apply to all the salts tested and that both the anion and the cation affect a salt's stimulating effectiveness.

Action Potentials↗

PubMed1999

Alkali-treated collagen retained the triple helical conformation and the ligand activity for the cell adhesion via alpha2beta1 integrin.

Alkaline treatment is a good method for extracting collagen with high recovery even from an aged animal specimen. However, the properties of collagen treated under alkaline conditions have not been well established yet. By the treatment with a solution of 3% sodium hydroxide and 1.9% monomethylamine, the isoelectric point of type I collagen was lowered from 9.3 to 4.8 because of the conversions of Asn and Gln to Asp and Glu. With the acidification of the pI, the denaturation temperature of the collagen was decreased from 42 to 35 degrees C after 20 d treatment, but the collagen-specific triple helical conformation was maintained. Human keratinocytes and fibroblasts adhered to the alkali-treated collagen via the collagen receptor integrin alpha2beta1. This indicates that the alkali-treated collagen maintained its property as a biological adherent molecule. Unlike acid-soluble collagen, alkali-treated collagen lost the ability to form fibrils at neutral pH under physiological conditions. This ability was lost even after 4 h of alkaline treatment, when the denaturation temperature of the collagen did not change. On the other hand, the alkali-treated collagen formed a fibrous precipitate with a uniform diameter of 50-70 nm under acidic conditions at 30 degrees C.

Alkalies↗

PubMed1993

Ingestion of caustic alkali farm products.

Since the Poison Prevention Packaging Act took effect, the number of ingestions of caustic alkali from household products has been significantly reduced. Commercial caustic alkalis used on farms, however, were not included in this legislation. Fourteen children over a 5 year period were seen after ingestion of commercial caustic alkalis used on farms. Seven of the children had ingested liquid pipeline cleaners and seven had ingested solid agents used for a variety of reasons. Six of seven children ingesting liquid agents did so from nonoriginal containers into which the caustic had been transferred for convenience. All seven children ingesting solid agents did so from the original container. Eight of the 14 children were found to have second-degree or worse esophageal involvement. Both solid and liquid caustic agents used commercially on farms can cause significant morbidity. Development of a child-resistant container for daily transfer of liquid pipeline agents could be helpful in preventing injuries from liquid pipeline cleaners. Pediatric gastroenterologists as well as primary care physicians in rural areas should be familiar with this type of injury and should take an active role in instructing parents of children living on farms to prevent such injuries. Extension of the Poison Prevention Packaging Act to caustic alkalis used on farms needs to be considered.

Adolescent↗

PubMed1975

Membrane potential and conductance during pinocytosis induced in Amoeba proteus with alkali metal ions.

An investigation of the relationship between the polarized state of the membrane and the onset and the intensity of pinocytosis was made in Amoeba proteus. Membrane potential and input resistance was in all instances found to decrease in approximate proportion to the number of channels when pinocytosis was induced by a variety of alkali metal ions at varying pH. Channels began to appear when the membrane was depolarized to -30 mV by the inducer of pinocytosis. With all inducers the maximum pinocytosis was encountered at membrane potentials close to zero. No positive potentials were recorded when the chloride salts of the inducing cations were used. At high concentrations of alkali ions a transient increase of the chloride permeability caused short-lasting hyperolarizations of the membrane. Inhibition of pinocytosis by Ca++ was accompanied by an increase of input resistance and membrane potential. The selectivity of the membrane to different alkali metal ions observed as changes in pinocytosis intensity, membrane potential and input resistance was found to vary with the concentration of the inducer and with the Ca++ concentration of the extracellular solution. Displacement of membrane bound Ca++ appeared to decrease the field strength of charged groups in the membrane altering its selectivity among alkali cations. The formation of pinocytotic channels is suggested to require translocation of Ca++ from the membrane into the cell and would therefore be closely related to the electrical properties of the amoeba.

Alkalies↗

PubMed1979

Pepsin 5 in gastric juice: determination and relationship to the alkali-stable peptic activity.

Pure human pepsins 1 and 3 are inactivated by incubation at pH 7.1-7.3 for 30 minutes, losing 90% or more of activity. Pepsin 5 is alkali-stable, retaining 100% of activity. Mixtures of pure pepsins 1 and/or 3 with pepsin 5 were found to have greater alkali-stable activity than predicted. Two published methods for determining the alkali-stable fraction of the peptic activity of gastric juice gave, respectively, in our hands values of 45.4-80.0% and 27.5-43.9% of the total activity. These values seemed too high to be attributable only to pepsin 5 in gastric juice, as agar gel electrophoresis shows pepsin 3 to have the principal activity. Electrophoretograms of alkaline incubated gastric juice revealed that large amounts of pepsin 3 retained activity as well as pepsin 5, and a proteolytic zone "4" appeared between them. Alkali inactivation thus does not allow the estimation of pepsin 5 individually in gastric juice. Pepstatin, at a final concentration of 100 to 170 pmol/ml, may be used to estimate pepsin 5 in gastric juice and gave values of 18.0 to 27.6% of the total peptic activity. Pepsin 5, in gastric juice and in mixtures of pepsins, appears to protect pepsin 3 from alkaline-inactivation, and to a lesser extent from pepstatin inhibition.

Alkalies↗

PubMed2026

Characterization of oxidative status in maize protoplasts under temperature and saline-alkali stresses.

BACKGROUND: Protoplasts have emerged as a powerful model system in plant functional genomics, offering significant utility in functional gene analysis, protein interaction studies, and transient expression platforms for gene editing. Despite their versatility, inherent limitations restrict their broader application, highlighting the need for systematic investigations into their responses to abiotic stressors, such as temperature fluctuations and saline-alkali conditions (200 mM saline mixture: 170mM NaCl and 30mM Na2CO3, pH = 9.1). RESULTS: In this study, we comprehensively examined the effects of varying temperatures and saline-alkali stress on the integrity, viability, and reactive oxygen species (ROS) metabolism of maize protoplasts. Key markers of oxidative stress-including ROS accumulation, lipid peroxidation (measured as malondialdehyde, MDA), antioxidant enzyme activity (superoxide dismutase, SOD), and hydrogen peroxide (H2O2) levels-were quantified to assess the oxidative stress response. Protoplasts maintained at 4 °C demonstrated enhanced stability and antioxidant capacity, preserving cell viability and endogenous protein integrity for up to 16 h. Conversely, exposure to 37 °C significantly compromised protoplast viability, while incubation at 28 °C exerted minimal effects within 16 h. CONCLUSIONS: Our study investigated the effects of various temperature stresses and salt-alkali stress on maize protoplasts. The results demonstrated that both temperature and salt-alkali stress significantly impacted protoplast production, viability, and the expression of endogenous proteins. These findings not only characterize the redox response of maize protoplasts, but also provide guidance for protoplast isolation and other procedures: 4 °C is suitable for short-term maintenance, 25-28 °C for routine functional assays, and 37 °C should be avoided. These findings provide valuable insights into the stress responses of protoplasts and establish a foundation for future research aimed at improving plant stress tolerance through protoplast-based techniques.

Zea mays↗

PubMed2005

Extracellular sensors and extracellular alarmones, which permit cross-talk between organisms, determine the levels of alkali tolerance and trigger alkaliinduced acid sensitivity in Escherichia coli.

For several stress responses in Escherichia coli, switching on involves conversion by the stress of an extracellular stress sensor (an extracellular sensing component, ESC) to an extracellular induction component (EIC), the latter functioning as an alarmone and inducing the response. The aim of this study was to establish whether alkali tolerance induction at pH 9.0, alkali sensitisation induced at pH 5.5 and the acid sensitisation induced at pH 9.0 involve sensing of pH changes by ESCs. The techniques involved made use of studies with cell-free culture filtrates. With respect to the inducible responses under test, these filtrates were prepared either from induced or uninduced cultures and filtrates from uninduced cultures were also activated in vitro, by the pH stress, in the absence of bacteria. Tests were then made to examine whether EICs (known to be needed for all these systems) are formed by activation, at the appropriate pH values, of filtrates from pH 7.0-grown cultures (i.e. uninduced culture filtrates); appearance of an EIC on activation would indicate the presence in the uninduced culture filtrate of an ESC. The studies showed that all three systems use ESCs to detect pH changes. Tests involving attempted enzymic and physical inactivation of the ESCs, and attempted removal of the ESCs by dialysis, showed that the ESC involved in alkali sensitisation is a small very heat-resistant protein. Strikingly, protease only partially inactivated the ESCs needed for alkali tolerance induction and for acid sensitisation; each system may be complex, involving both protein and non-protein (RNA?) ESCs, although other explanations are possible. It was also established that appropriate killed cultures can induce all three responses when incubated with pH 7.0-grown living cultures. The occurrence of ESC/EIC pairs for these three responses has led to the evolution of early warning systems for each, the diffusibility of the EICs, and their interaction with non-producers, allowing them to act pheromonally, inducing sensitive organisms to stress tolerance, prior to exposure to stressor.

Acids↗

PubMed1992

Ingestion of strong corrosive alkalis: spectrum of injury to upper gastrointestinal tract and natural history.

We have prospectively studied 31 patients who ingested strong alkalis for location, extent, severity, and outcome of the injury to the upper gastrointestinal tract. Alkalis ingested were sodium hydroxide (n = 28) and potassium hydroxide (n = 3). The injury was assessed within 36 h of alkali intake by endoscopy or surgery, or at autopsy. Symptoms and signs did not give a reliable forecast of the extent and severity of injury. The corrosive burns were classified as grade 2a in six patients, grade 2b in eight, and grade 3 in 17. The esophagus was injured in all patients, the stomach in 93.5%, and the duodenum in 29.6%. Acute complications occurred in 32.3% of the patients and death in 12.9%; all but one of such patients had grade 3 burns. All patients with 2a injury recovered without sequelae. Four of the eight patients with grade 2b injury and all survivors of grade 3 injury developed esophageal or gastric cicatrization, or both, which needed endoscopic or surgical treatment. We find endoscopy is not only a safe and reliable tool for diagnosis in such patients, but also is of importance in treatment and prognosis. We conclude that ingestion of strong alkalis is a very serious condition that inflicts severe contiguous injury to the esophagus and stomach and results in high morbidity and mortality.

Adolescent↗

PubMed2006

[Adaptability of Litopenaeus vannamei to saline-alkali water in west Jilin Province].

By supplementing natural saline-alkali water into desalinated prawn-cultivating pond, this paper studied the survival ability of Litopenaeus vannamei under saline-alkali water environment. The results showed that the survival duration of untamed juvenile shrimp was more than 96 hours at the alkalinity of saline-alkali water from 5.15 to 19.24 mmol x L(-1), and less than 0.75 hours at the alkalinity from 23.41 to 38.78 mmol x L(-1). The survival duration of tamed juvenile shrimp was more than 24 hours at the alkalinity from 5.15 to 38.78 mmol x L(-1). The upper limit of alkalinity adapted by untamed juvenile shrimp was about 10 mmol x L(-1), and the adaptability to the increasing disparity in alkalinity was under 8 mmol x L(-1). The adaptability of juvenile shrimp could be increased by the increase of tamed standard, and that of tamed juvenile shrimp to the alkalinity of 30 mmol x L(-1) was from 2 to 4 mmol x L(-1) and from 3 to 25 mmol x L(-1) for the alkalinity disparity increase and decrease, respectively. Litopenaeus vannamei could be cultivated in the saline-alkali water with an alkalinity of 32 mmol x L(-1) in west Jilin Province.

Adaptation, Psychological↗