Effects Of Environmental pH Research Articles

Combined transcriptomic and metabolomic analysis revealed that pH changes affected the expression of carbohydrate and ribosome biogenesis-related genes in Aspergillus niger SICU-33.

The process of carbohydrate metabolism and genetic information transfer is an important part of the study on the effects of the external environment on microbial growth and development. As one of the most significant environmental parameters, pH has an important effect on mycelial growth. In this study, the effects of environmental pH on the growth and nutrient composition of Aspergillus niger (A. niger) filaments were determined. The pH values of the medium were 5, 7, and 9, respectively, and the molecular mechanism was further investigated by transcriptomics and metabolomics methods. The results showed that pH 5 and 9 significantly inhibited filament growth and polysaccharide accumulation of A. niger. Further, the mycelium biomass of A. niger and the crude polysaccharide content was higher when the medium's pH was 7. The DEGs related to ribosome biogenesis were the most abundant, and the downregulated expression of genes encoding XRN1, RRM, and RIO1 affected protein translation, modification, and carbohydrate metabolism in fungi. The dynamic changes of pargyline and choline were in response to the oxidative metabolism of A. niger SICU-33. The ribophorin_I enzymes and DL-lactate may be important substances related to pH changes during carbohydrate metabolism of A.niger SICU-33. The results of this study provide useful transcriptomic and metabolomic information for further analyzing the bioinformatic characteristics of A. niger and improving the application in ecological agricultural fermentation.

Effects of environmental pH on protein properties and flavor factors of hairtail (Trichiurus haumela) in thermal processing

The flavor and texture of hairtail (Trichiurus haumela) products easily change depending on the processing conditions including the programed temperature, environmental pH, and so on. In the present study, we aimed to explore the differences in the overall texture and flavor of hairtail under heat treatment with varied environmental pH. The results indicated that the secondary structure of the myofibrillar protein in thermal processed hairtail meat presented a transformation from α-helix to β-sheet structure with the decrease of solution pH. Moreover, heat treatment in an acidic solution environment effectively improved the sensory and flavor properties of hairtail. In addition, pH-mediated changes on protein characteristics of cooked hairtail meat showed significant correlation with the texture properties, while weakly correlated with the flavor.

Effect of Oral Environmental pH on the Dynamic Characterization of Bioactive Restorative Materials

The objective of this study was to investigate the effects of oral environmental pH on the viscoelastic properties of bioactive restorative materials (BRMs) by using dynamic mechanical analysis. Stainless steel molds were used to fabricate 40 beam-shaped specimens (12 × 2 × 2 mm) for each material. The specimens were finished, measured, randomly divided into four groups (n = 10), and immersed in aqueous solutions of pH 3.0, 5.0, 6.8, and 10.0 at 37 °C for seven days. The specimens were then subjected to dynamic mechanical analysis with a 5 N load and frequency range of 0.1-10.0 Hz. Data were analyzed using one-way ANOVA/Dunnet T3’s test (α = 0.05). Mean elastic modulus spanned from 2.68 ± 0.17 to 6.49 ± 0.71 GPa, while viscous modulus ranged from 0.43 ± 0.03 to 0.62 ± 0.12 GPa. Loss tangent differed from 77.30 ± 4.90 to 164.50 ± 9.12. Significant differences among pH were discerned for (i) Elastic modulus: Cention N - pH 3.0, 5.0, 10.0 > 6.8; Activa Bioactive - pH 3.0, 6.8, 10.0 > 5.0, (ii) Viscous modulus: Cention N - pH 3.0, 5.0, 10.0 > 6.8, and (iii) Loss tangent: Activa Bioactive - pH 5.0 > 3.0, 6.8, 10.0. Significant differences in viscoelastic properties were noted among the BRMs with Activa Bioactive presenting the lowest elastic modulus for all pH. Immersion of all materials in pH 6.8 yielded the highest elastic modulus, except for Activa Bioactive. The effects of environmental pH on viscoelastic properties of BRMs are material-dependent.

Effects of Environmental pH on the Growth of Gastric Cancer Cells.

Background Proton pump inhibitor (PPI) and other acid-suppressing drugs are widely used in the treatment of gastrointestinal ulcer, upper gastrointestinal bleeding, gastritis, and gastric cancer (GC). About 80% of GC patients receive acid suppression treatment. PPI suppresses the production of gastric acid by inhibiting the function of H+/K+-ATPase in gastric parietal cells and raises the pH value to achieve therapeutic purposes. Some studies have found that PPI had a certain antitumor effect in the proliferation and apoptosis of tumor cells. But the effects of environmental pH on the growth of GC cells and its mechanism are unknown. Therefore, we hoped to find the effects of culture medium pH on the biological behavior of GC cells by in vitro experiments and provide guidance for the use of acid-suppressing drugs in GC patients. Aims We aimed to observe the effects of pH changes in GC cell culture medium on the cell biological behavior of cancer cells and to analyze the potential mechanisms. We hoped to find out the effect of acid suppression on the growth of GC cells. Methods The GC cell lines (SGC-7901 and MKN45) were used as the research object. We adjusted the pH value in the cell culture medium to observe the changes in cell viability (MTT), apoptosis (flow cytometry), and invasion (Transwell) at pH 6, pH 7, and pH 8. qRT-PCR and western blot (WB) assays were used to determine the expression changes of genes and proteins (mTOR, AKT, Wnt, Glut, and HIF-1α) at pH 6, pH 7, and pH 8. Results The results of MTT showed that the viability of SGC-7901 and MKN45 in the pH 8.0 group was significantly weaker than that in the pH 6.0 or pH 7.0 group (P < 0.001). Flow cytometry results showed that the apoptosis of SGC-7901 and MKN45 in the pH 8.0 group was more obvious than that in the pH 6.0 or pH 7.0 group (P < 0.001). Flow cytometry results showed that the apoptosis of SGC-7901 and MKN45 in the pH 8.0 group was more obvious than that in the pH 6.0 or pH 7.0 group (P < 0.001). Flow cytometry results showed that the apoptosis of SGC-7901 and MKN45 in the pH 8.0 group was more obvious than that in the pH 6.0 or pH 7.0 group (α) at pH 6, pH 7, and pH 8. P < 0.001). Flow cytometry results showed that the apoptosis of SGC-7901 and MKN45 in the pH 8.0 group was more obvious than that in the pH 6.0 or pH 7.0 group (Conclusions Compared with the microacid environment, the microalkaline environment inhibited the viability, invasion, and expression of genes and proteins (mTOR, AKT, Wnt, Glut, and HIF-1α) but promoted the apoptosis of GC cells and thus inhibited the growth of GC.α) at pH 6, pH 7, and pH 8.

Effects of Environmental pH on Macrophage Polarization and Osteoimmunomodulation.

Biodegradable bone materials can degrade gradually in response to physiological environment and simultaneously promote bone regeneration, thus avoiding the demand of secondary surgery. With the continuous degradation, the environmental pH around the materials could be significantly changed. In the current work, the effects of environmental pH on macrophage polarization and osteoimmunomodulation were investigated. The results showed that the viability of macrophages was inhibited when pH decreased from 7.4 to 6.2 while remained unchanged when pH increased to 8.6. The morphology of macrophages was sensitive to environmental pH changes. The roundish macrophages (pH 7.4) transformed fusiform and polygon-shaped cells at pH 6.6 and 8.2, respectively. The polarization state of macrophages was also found to be pH-dependent. The acidic environment (pH 6.6) tended to polarize macrophages to M2 phenotype, evidenced by the enhanced secretion of arginase-1 (Arg-1), downregulated expressions of M1-related genes such as CD86, tumor necrosis factor-α (TNF-α), interleukin-27 (IL-27), and IL-1β as well as upregulated gene expression of M2 surface marker CD206. The alkaline environment (pH 8.2) led to M1 polarization of macrophages, evidenced by the enhanced production of inducible nitric oxide synthase and upregulated expressions of M1-related genes such as CD11c, TNF-α, IL-1β, and IL-6. Moreover, the gene expressions of growth factors including bone morphogenetic protein-2 (BMP-2), BMP-6, and oncostatin-M (OSM) as well as toll-like receptor (TLR) pathways (TLR-3, TLR-4, and MyD88) were also upregulated at pH 8.2. In addition, the alkaline environment (pH 8.2) was found to exhibit a positive osteoimmunomodulatory effect because the microenvironment created by culturing macrophages in the culture medium with a pH value of 8.2 promoted the alkaline phosphatase (ALP) activity, collagen (Col) production, mineralization, as well as the gene expressions of ALP, Col-I, and osteocalcin (OCN) in osteoblasts. It is considered to be attributed to the enhanced productions of BMP-6 and OSM by macrophages in response to the alkaline environment (pH 8.2). The osteoimmunomodulatory effect of acidic environment (pH 6.6) was found to be weaker. Together, the results indicate that the behaviors of macrophages such as viability, morphology, and polarization state could be modulated by extracellular pH change. The development of novel biomaterials that can create a proper alkaline microenvironment at the materials/bone interface could be beneficial for enhanced bone regeneration.

Effects of environmental pH and ionic strength on the physical stability of cinnamaldehyde-loaded liposomes

The physical stability of cinnamaldehyde-loaded liposomes was investigated under various conditions including different storage time, storage temperature, pH and ionic strength of external environment, as well as variations in hydration media. Results showed that the average diameter of liposomes increased first and remained constant, the retention rate (RR) decreased while the liposomes stored at higher temperature exhibited a lower RR during the storage period of 9 days. Furthermore, liposomes under acidic conditions (pH ≤ 6) exhibited a decreased particle size with an increased RR. As for the ionic strength of the external environment and hydration media, the particle size of liposomes increased, whereas the RR and encapsulation efficiency (EE) decreased as ionic strength increased. Atomic force microscopy (AFM) further proved that high ionic strength could result in instability of liposomes. However, the particle size of liposomes in the external environment composed of ion solution were far more than those in the hydration media, which indicated that the liposomes prepared in ion solution could resist instability caused by changes in external ionic strength. These results also provided a guidance for the application of liposomes in different environments and selectively preparing desired liposomes by modulating the pH and ionic strength of environment.

Effects of Environmental pH on Antioxidant Interactions between Rosmarinic Acid and α-Tocopherol in Oil-in-Water (O/W) Emulsions.

Antioxidant regeneration could be influenced by various factors such as antioxidant locations and pH conditions. The effects of environmental pH on the antioxidant interaction between rosmarinic acid and α-tocopherol in oil-in-water (O/W) emulsions were investigated. Results showed that the combined antioxidants at pH 7 exhibited the strongest synergistic antioxidant activity in comparison with the combinations at other pH conditions as indicated by the interaction index. A drop in pH from 7 to 3 resulted in a reduction in the synergistic effect. However, in the case of pH 3, an additive effect was obtained. Moreover, the effect of the pH on the regeneration of α-tocopherol by rosmarinic acid in heterogeneous Tween 20 solutions was studied using EPR spectrometer. The same was true for the regeneration efficiency, where the reaction at pH 7 exhibited the highest regeneration efficiency of 0.3 mol of α-tocopheroxyl radicals reduced/mol of phenolics. However, the study on depletions of rosmarinic acid and α-tocopherol revealed that the formation of caffeic acid, an oxidative degradation product of rosmarinic acid, could be involved in enhancing the antioxidant activity observed at pH 7 rather than the antioxidant regeneration. This study has highlighted that the importance of pH-dependent antioxidant interactions does not solely rely on antioxidant regeneration. In addition, the formation of other oxidative products from an antioxidant should be taken into account.

Potential transbuccal delivery of l-DOPA methylester prodrug: stability in the environment of the oral cavity and ability to cross the mucosal tissue

Levodopa (l-DOPA) is the most effective pharmacologic agent in Parkinson’s disease and remains the “gold standard”. Nevertheless, in long-term treatments, dyskinesias and motor complications can emerge. In this work, the combined use of l-DOPA methylester hydrochloride prodrug (LDME) with transbuccal drug delivery was supposed as a good alternative method to optimize the bioavailability of l-DOPA, to maintain constant plasma levels and to decrease the drug unwanted effects. The effects of environmental pH on buccal delivery of LDME were evaluated ex vivo. The increase of pH value from 5.8 to 6.2 implies an improvement of drug permeation. Since the pH increase causes the raising of hydrolytic conversion of LDME to l-DOPA, the pH value 6.2 was considered as a good compromise between drug stability and permeation rate. It was found that during the passage through the biological tissue, LDME undergoes a primary conversion to l-DOPA catalyzed by membrane’s enzymes. Supplementation of delivery with Tween 80® produces substantial enhancement of LDME passage through the membrane. The drug could be loaded in the IntelliDrug mechatronic device, released close to the buccal mucosa, so achieving and maintaining constant therapeutic blood levels for extensive time.

Effects of environmental pH on ammonia excretion, blood pH, and oxygen uptake in fresh water crustaceans

1. In Procambarus clarki and Procambarus fallax, ammonia excretion increases in response to low ambient water pH. These findings do not differentiate between the alternative hypotheses that the reduction in ambient water pH (a) stimulates the passive diffusion of ammonia, and/or (b) inhibits Na +/NH 4 + ATPase activity. 2. The ammonia excretory rate of Orconectes rusticus remains constant with changes in water pH. 3. In normoxic water, oxygen uptake in P. clarki and O. rusticus is maintained in response to changes of ambient water pH.

Influence du pH du milieu au cours de la fécondation sur la survie embryonnaire de la carpe commune (Cyprinus carpio)

The effects of environmental pH during fertilization in carp eggs were studied by measuring the percentage of prehatching embryonic survival. These effects, which may be delayed beyond epiboly, were the same when the treatments lasted 15 and 30 min after insemination, and they were not modified either by the addition of a physiological salt solution to the medium or by exposure of the eggs for 10 s before insemination. Among the six types of buffer used, phosphate buffers were particularly toxic which may indicate the role played by calcium during fertilization. Normal fertilization requires that the osmolarity of the medium be lower than or equal to 200 mosmol/kg. Beyond the limits of favorable pH values (7.2 and 9.6), egg tolerance decreased less rapidly in a weakly buffered medium than in a strongly buffered one. In such a medium, there was no resistance at pH 6.2 or 9.9.

Effects of environmental pH and temperature on embryonic survival capacity and metabolic rates in the smallmouth salamander, Ambystoma texanum.

Although the deleterious effects of acid precipitation on forest ecosystems and fisheries have been documented, relatively little information is available on the effects of environmental pH in combination with temperature on the survival capacity and/or physiology of amphibians. Increased acidity resulting from acid precipitation common to the northwestern United States, can lead to increased mortality in the spotted salamander, Ambystoma maculatum. In view of the potentially significant deleterious effects of stressful pH conditions on amphibian survivorship and the relative paucity of data on this subject, the present study was conducted in order to ascertain the combined effects of temperature and pH on embryonic metabolic rates and survival capacity in the smallmouth salamander, Ambystoma texanum Mathes. No previous data on these parameters are available for this species.

Effects of Environmental pH and Calcium on Ammonia Toxicity in Channel Catfish

Abstract The twenty-four-hour median lethal concentrations (24-hour LC50) of total ammonia nitrogen (TA-N) to channel catfish (Ictalurus punctatus) at pH 7, 8, and 9 (total hardness, 40 mg/liter; temperature, 21–25 C) were 263.6 ± 11.3 (SE), 38.8 ± 1.8, and 4.5 ± 0.2 mg/liter, respectively. The 24-hour LC50 of un-ionized ammonia nitrogen (UIA-N) concentration at pH 8 was significantly higher (1.82 ± 0.06 mg/liter) than at pH 7 or 9 (1.39 ± 0.06 and 1.49 ± 0.12 mg/liter). Enrichment of the water to 440 mg/liter total hardness at pH 7 significantly increased the 24-hour LC50 of TA-N and UIA-N (356.3 ± 16.4 and 1.79 ± 0.07). Fish exposed to 25 mg/liter TA-N for 12 hours at pH 7 and 8 showed no differences from control fish in hematocrit, percent total plasma protein, or plasma and muscle chloride. Plasma sodium showed no difference between control and experimental groups at pH 7; however, a significant decrease occurred in fish exposed to 25 mg/liter TA-N at pH 8. No differences in blood pH were found betwee...

Environmental pH and the recovery of H-1 parvovirus during single cycle infection

The effects of environmental pH on the production and release of H-1 parvovirus were examined in a one-cycle infection of synchronized NB cells (SV40 transformed newborn human kidney cells). Using standard hemagglutination and plaque assay methods the total amount of virus detected in cultures incubated at different pH's was found to increase with decreasing proton concentration from pH 7.0 to 8.0, by 2000 times for HA and 22-fold for infectious virus. However, when the pH's of the infected cell lysates were all adjusted to pH 8.0 before assay the differences were reduced or eliminated. Reconstruction experiments using cell sonicates treated with DNAse or nonionic detergents showed that the adsorption and release of virus from membranous material in the cell homogenates was strongly pH dependent. Electron microscopic studies indicated an extensive H-1 virus adsorption to cell membranes at relatively low environmental pH. The apparent effects of pH on H-1 replication were thus attributable to the potentiation or inhibition of release of virus from cell receptors rather than to the influencing of the intermediate steps of virus production.

Effects of environmental pH, sodium concentration, and temperature on the spontaneous motility of isolated human uterine muscle

Effects of environmental pH, sodium concentration, and temperature on the spontaneous motility of isolated human uterine muscle