Low pH Research Articles

Molecular Dynamics Simulation of Lipid Nanoparticles Encapsulating mRNA.

mRNA vaccines have shown great potential in responding to emerging infectious diseases, with their efficacy and stability largely dependent on the delivery vehicles-lipid nanoparticles (LNPs). This study aims to explore the mechanisms by which LNPs encapsulate mRNA, as well as the effects of different N/P ratios and acid types in nucleic acid solutions on the structure and properties of LNPs, using the ethanol solvent injection method as the encapsulation technique. Six systems were designed, based on the composition and proportions of the existing mRNA vaccine mRNA-1273, and molecular dynamics (MD) simulations were employed to investigate the self-assembly process of LNPs. Ethanol was used as a solvent instead of pure water to better mimic experimental conditions. The results indicate that lipid components self-assemble into nanoparticles under neutral conditions, with the ionizable lipid SM-102 predominantly concentrating in the core of the particles. Upon mixing with nucleic acids in acidic conditions, LNPs undergo disassembly, during which protonated SM-102 encapsulates mRNA through electrostatic interactions, forming stable hydrogen bonds. Cluster structure analysis revealed that the four lipid components of LNPs are distributed sequentially from the outside inwards as DMG-PEG 2000, DSPC, cholesterol, and protonated SM-102. Moreover, LNPs constructed under low pH or low N/P ratios using citric acid exhibited larger volumes and more uniform distribution. These findings provide a scientific basis for further designing and optimizing LNP components to enhance the efficacy of mRNA vaccine encapsulation.

Co-expression of endoglucanase and cellobiohydrolase from yak rumen in lactic acid bacteria and its preliminary application in whole-plant corn silage fermentation.

Endoglucanase (EG) and cellobiohydrolase (CBH) which produced by microorganisms, have been widely used in industrial applications. In order to construct recombinant bacteria that produce high activity EG and CBH, in this study, eg (endoglucanase) and cbh (cellobiohydrolase) were cloned from the rumen microbial genome of yak and subsequently expressed independently and co-expressed within Lactococcus lactis NZ9000 (L. lactis NZ9000). The recombinant strains L. lactis NZ9000/pMG36e-usp45-cbh (L. lactis-cbh), L. lactis NZ9000/pMG36e-usp45-eg (L. lactis-eg), and L. lactis NZ9000/pMG36e-usp45-eg-usp45-cbh (L. lactis-eg-cbh) were successfully constructed and demonstrated the ability to secrete EG, CBH, and EG-CBH. The sodium carboxymethyl cellulose activity of the recombinant enzyme EG was the highest, and the regenerated amorphous cellulose (RAC) was the specific substrate of the recombinant enzyme CBH, and EG-CBH. The optimum reaction temperature of the recombinant enzyme CBH was 60°C, while the recombinant enzymes EG and EG-CBH were tolerant to higher temperatures (80°C). The optimum reaction pH of EG, CBH, and EG-CBH was 6.0. Mn2+, Fe2+, Cu2+, and Co2+ could promote the activity of CBH. Similarly, Fe2+, Ba2+, and higher concentrations of Ca2+, Cu2+, and Co2+ could promote the activity of EG-CBH. The addition of engineered strains to whole-plant corn silage improved the nutritional quality of the feed, with the lowest pH, acid detergent fiber (ADF), and neutral detergent fiber (NDF) contents observed in silage from the L. lactis-eg group (p < 0.05), and the lowest ammonia nitrogen (NH3-N), and highest lactic acid (LA) and crude protein (CP) contents in silage from the L. lactis-eg + L. lactis-cbh group (p < 0.05), while the silage quality in the L. lactis-cbh group was not satisfactory. Consequently, the recombinant strains L. lactis-cbh, L. lactis-eg, and L. lactis-eg-cbh were successfully constructed, which could successfully expressed EG, CBH, and EG-CBH. L. lactis-eg promoted silage fermentation by degrading cellulose to produce sugar, enabling the secretory expression of EG, CBH, and EG-CBH for potential industrial applications in cellulose degradation.

Effective Removal of Selenium from Aqueous Solution using Iron-modified Dolochar: A Comprehensive Study and Machine Learning Predictive Analysis

Selenium (Se) is an essential micronutrient for human beings, but excess concentration can lead to many health issues and degrade the ecosystem. This study focuses on the removal of selenium from an aqueous solution using iron-doped dolochar. SEM, EDX, BET, XRD, FTIR, and Pzpc were conducted to determine the surface characteristics of iron-doped dolochar (FeD). The characterization of the adsorbent gave an insight into surface morphology, surface area (100 m2/g), average pore diameter (3.9 nm), and surface composition, which contributed to the Se adsorption. The pHzpc of the iron-doped adsorbent surface was found to be 7.02, which provided a broad range for effective Se adsorption. To detect the optimum parameters, the parametric influence on removal efficiency was conducted by varying pH, dosages, contact time, and initial concentration. The experiment achieved maximum selenium removal, ∼98 %, at low concentration, 10 g/L dosage, and low pH (2) within 90 min at room temperature. It fits the Langmuir better than the Freundlich isotherm (R2 = 0.99), indicating monolayer adsorption. It fitted well with pseudo-second-order kinetics. The experiment is a spontaneous, endothermic (ΔH0 = 9.22 kJ/mol) and high randomness (ΔS0 = 45.37 kJ/mol) suggested by thermodynamic study. The adsorption was influenced by competing ions as follows: phosphate > sulfate > nitrate > manganese > aluminum > zinc > iron. A regression learner tool was used to compare different models using the experimental data that showed the best fit with the Gaussian Process Regression with RMSE = 0.246, MSE = 0.061, and R2 = 0.99. Thus, it can be concluded that FeD is preferred as a better adsorbent for selenium removal from aqueous solutions and could produce 35.5% ROI, 21.5% IRR, and 24.59% BEP on FeD production.

Acidity suppresses CD8 + T-cell function by perturbing IL-2, mTORC1, and c-Myc signaling.

CD8 + T cells have critical roles in tumor control, but a range of factors in their microenvironment such as low pH can suppress their function. Here, we demonstrate that acidity restricts T-cell expansion mainly through impairing IL-2 responsiveness, lowers cytokine secretion upon re-activation, and reduces the cytolytic capacity of CD8 + T cells expressing low-affinity TCR. We further find decreased mTORC1 signaling activity and c-Myc levels at low pH. Mechanistically, nuclear/cytoplasmic acidification is linked to mTORC1 suppression in a Rheb-, Akt/TSC2/PRAS40-, GATOR1- and Lkb1/AMPK-independent manner, while c-Myc levels drop due to both decreased transcription and higher levels of proteasome-mediated degradation. In addition, lower intracellular levels of glutamine, glutamate, and aspartate, as well as elevated proline levels are observed with no apparent impact on mTORC1 signaling or c-Myc levels. Overall, we suggest that, due to the broad impact of acidity on CD8 + T cells, multiple interventions will be required to restore T-cell function unless intracellular pH is effectively controlled.

Extraction optimisation and characterisation of Artocarpus integer peel pectin by malonic acid-based deep eutectic solvents using response surface methodology

Traditional pectin extraction methods involve strong acids, which are environmentally harmful. This study explores an innovative approach using Malonic Acid (MA)-based Deep Eutectic Solvents (DES) to extract pectin from Artocarpus integer Peel (AIPP), optimised through Response Surface Methodology (RSM). The extracted AIPP-A and AIPP-B from ChCl-MA and ChDHCit-MA DES, respectively, were characterised for yield, pH, solubility, Degree of Esterification (DE), Water and Oil Holding Capacity (WHC and OHC). The experimental values aligned with RSM model predictions, with low standard deviations: 0.7300 for ChCl-MA and 0.1531 for ChDHCit-MA. Optimal extraction conditions for AIPP-A were 3.27 % ChCl-MA, 1.28 h extraction time, 50.44 °C temperature, and a 1:40 g/mL solid-to-liquid ratio. For AIPP-B, the conditions were 4.95 % ChDHCit-MA, 2.04 h extraction time, 79.65 °C temperature, and a 1:50 g/mL solid-to-liquid ratio. ChCl-MA yielded 30.97 % AIPP, which was higher than that of ChDHCit-MA (27.99 %). Both AIPP demonstrated desirable properties such as low pH, high solubility, and significant DE. AIPP-A exhibited a greater DE (58.40 %) compared to AIPP-B (32.4 %) contributed to its lower WHC and higher OHC. In conclusion, RSM-based optimisation of AIPP extraction with DES is effective in producing pectin that is suitable for use as a gelling agent, preservative, and stabiliser in the food industry.

Use of N-acetyl-cysteine in the Perioperative Period of Liver Transplantation: A Scoping Review

Objective: To !nd evidence on the use of N-acetyl-cysteine (NAC) in the perioperative period of liver transplantation, since NAC, as it is the acetylated precursor of L-cysteine and reduced glutathione, contributes to the hepatic supply of glutathione, helping the liver to recover from ischemia and reperfusion injury. Methodology: "is is a scoping review of the PubMed, VHL and Web of Science databases. "e descriptors “Liver transplantation”, “N-acetyl-cysteine” and “Reperfusion Ischemia” were used, with the Boolean operator “AND”, and articles relevant to the topic were selected. Initially, 60 articles were selected, all published in the last 24 years, in Portuguese and/or English. After analysis, eight articles corresponded to the proposed objective. Results:"e groups that received NAC during TxF showed post-reperfusion hypotension, lower intraoperative pH values, higher plasma concentrations of IL-4 and a signi!cant increase in IL-10 levels !ve minutes before reperfusion. Inhibition of α-glutathione S-transferase (α-GST) was also observed after reperfusion, unlike the control group, which showed a signi!cant increase in this enzyme. Furthermore, sVCAM-1 and sICAM-1 levels were signi!cantly lower in the NAC group 24 hours after reperfusion compared with the placebo group. "e maximum AST value during the !rst 72 postoperative hours was similar in both groups, although the peak ALT was lower in the NAC group than in the placebo group. In grafts that received NAC in the perfusion solution, survival rates at 3 and 12 months were 93% and 90%, respectively, and in the control group were 82% and 70%, respectively. "e incidence of postoperative complications was 23% in the NAC group and 51% in the control group. "e incidence of EPD was lower for the NAC group, which was 15% versus 32% in the control group. Regarding the administration of NAC during the intraoperative TxF, the one-year patient survival rate was 78.4% in the NAC group compared to 80.9% in the placebo group. Conclusion: Intraoperative administration of NAC during the anhepatic phase was associated with a protective effect against reperfusion injury, however in other studies limitations were observed in protection against liver injury, in biomarkers of oxidative stress, in in$ammation and in the functioning of liver enzymes.

IN VITRO AND IN VIVO INVESTIGATION OF PROBIOTICS ISOLATED FROM HUMAN MILK

People all over the world are embracing probiotics as a result of growing awareness of the health advantages connected to ingesting living bacteria. Proper administration of probiotics has been shown to provide numerous health advantages to the host. The Lactobacillus genus, which naturally resides in the mucosal linings of humans and animals, and it is essential for stabilizing the gastrointestinal tract and protecting intestinal health from infections. There has been a great deal of interest in their potential uses as probiotics, mucosal vaccine vectors, and agents regulating metabolic activities. The present study aimed at isolating and characterizing novel probiotics from human milk and functionally assessing them in vivo for their physiological, enzymatic and antimicrobial activity. Probiotic isolates from human milk were amylolytic, proteolytic and lipolytic and were found to be tolerant to low pH of 3.5, 10% salt and 0.3% bile salt. Primary method of cross streaking and secondary streaking by agar diffusion method revealed antagonistic activity of the isolates against tests pathogens of humans viz., S. aureus Newman, P. fluorescens, S. epidermis and S. aureus. Antibiofilm activity of probiotic isolates in vivo against P. fluorescens and S. aureus Newman indicated that the metabolites present in the Cell Free Supernatant (CFS) of the isolates may have the ability to inhibit the formation of biofilm of pathogenic strains. The most efficient probiotic isolates was identified as Weissella confusa and the NCBI GenBank accession number was obtained. The infected mice administered with probiotic isolate Weissella confusa PS17 showed reduced mortality rate than the mice infected with pathogenic strain S. aureus Newman, thus indicating that probiotic strain boosted the immune response of the mice. The Serum uric acid levels was normalised after the infected mice was treated with W. confusa PS17 and this in turn enhanced the survival rate of mice. The present study indicates that isolate W. confusa PS17 can be a promising candidate in improving the condition of health.

PSLBI-9 The growth performance and total tract starch digestibility of finishing Nelore bulls fed flint corn-based diets are improved by the corn processing method and urea source

Abstract The aim of this study was to evaluate the flint corn processing method (CPM) and urea source for finishing Nellore bulls fed corn-based diets. In this study, 80 Nellore bulls [initial body weight (BW) = 388 ± 45.7 kg] were allocated into 28 pens (7 pens/treatment; 6 pens with 3 bulls + 1 pen with 2 bulls). A completely randomized design with a 2 × 2 factorial arrangement of treatments was used to test two CPMs: dry ground corn (DGC) and reconstituted and ensiled corn (REC), and two US: feed-grade urea (FGU) and post-ruminal release urea (PRU). Dietary inclusion (% DM) of flint corn (vitreousness = 86.0%) was 61.3% (DGC or REC), and urea source addition was 0.5% as non-protein nitrogen (NPN; as FGU or PRU). The PRU source (Trouw Nutrition, Netherlands) contained 82% urea on a DM basis. In an in vitro assay, 27% of this urea was released into the rumen. Experimental period lasted 100 d (with 14 d of adaptation). Fecal samples from each bull were collected in two periods of three consecutive days (d 44 to 46 and 94 to 96) at different time (0600, 1200, and 1800 h). Samples were composited by pen and analyzed for fecal starch (FS) and indigestible NDF as markers for fecal excretion. At the end of the experiment, bulls were slaughtered and the jejunum and pancreas were sampled from one bull per pen. Interaction effects were not found (P ≥ 0.31) for any feedlot growth performance variables (Table 1). Final BW, average daily gain, and feed efficiency (gain to feed; G:F) were greater for bulls fed REC and PRU than for those fed DGC and FGU (P &amp;lt; 0.02), respectively. As a result, observed dietary net energy (NE) for maintenance and BW gain were about 7.0% and 9.0% greater for bulls fed REC diets, and 4.3% and 5.6% greater for bulls fed PRU diets, respectively. Bulls fed DGC had 2.2 times greater FS compared with bulls fed REC, resulting in lower fecal pH and total tract starch digestibility (TSD) for bulls fed DGC compared with those fed REC (P &amp;lt; 0.01). Interestingly, a similar trend was observed in bulls fed PRU compared with those fed diets with FGU (P &amp;lt; 0.06). Jejunal gene expression of SLC5A1 was not affected by treatments (P &amp;gt; 0.14). Nevertheless, bulls fed diets with PRU presented greater jejunal α-amylase activity (P = 0.02). Pancreatic α-amylase activity was less when bulls were fed DGC + PRU diet. In conclusion, REC markedly improved TSD and growth performance compared with DGC. Additionally, independent of CPM, PRU inclusion as NPN source increased G:F and dietary NE concentration due to the positive effects on jejunal amylase activity and TSD.

Mechanism and kinetics of scorodite formation in arsenic-bearing solutions using Fe(OH)3 as a solid iron source

Recently, solid iron sources have been used for scorodite synthesis in arsenic-bearing wastewater from nonferrous metallurgy. Immobilising arsenic-solution as scorodite via iron hydroxide (Fe(OH)3) solid iron source is an important method for controlling arsenic pollution. The evolution behavior of scorodite during its formation in high arsenic solution have been rarely investigated. In this paper, the mechanism and kinetics of scorodite formation using Fe(OH)3 in arsenic-bearing solution were investigated. This work was divided into three parts. Firstly, the influencing parameters were investigated, revealing that the dissolution of Fe(OH)3 and scorodite generation accelerated at lower initial pH and higher reaction temperature. Increasing Fe/As ratio delayed scorodite crystallisation, which was in turn enhanced by elevating arsenic concentration. Secondly, the mechanism of scorodite formation was investigated, revealing that Fe(OH)3 underwent acidic dissolution to form a precursor. Subsequent scorodite formation had a ΔrGmθ ranging from −69.39 kJ·mol−1 to −15.64 kJ·mol−1. Residual As was absorbed and converted into Fe(OH)3@scorodite. Thirdly, the chemical kinetics were investigated, showing that activation energy (Ea) for Fe(OH)3 dissolution was 72.54 and 105.37 kJ·mol−1 at Stages I and II, respectively, whereas it was 105.97 kJ·mol−1 for residual As absorption-conversion at Stage III outweighing the Ea of As-Fe coprecipitation. The restrictive steps were Fe(OH)3 dissolution and residual arsenic absorption-conversion. This proposed method can be applied for environment-friendly treatment of 10－40 g/L of arsenic-bearing industrial effluent for scorodite formation. Overall, this research confirmed the formation of scorodite via Fe(OH)3 and can potentially provide feasible schemes for eliminating arsenic-bearing acidic waste, dust, and anode slime from nonferrous metallurgical processes.

Synthesis and properties of oligopropylamines with photosensitive o-nitrobenzyl ester core

The o-nitrobenzyl ester group is known for more than 50 years as a convenient protecting group and fragment for the design of photosensitive systems, including drug delivery agents. Polymeric amines with these groups are promising systems for medical applications, but the lack of basic knowledge about the possible degradation of these compounds under physiological conditions restrains the development of real preparations. We synthesized five new polyamines with the insertion of the o-nitrobenzyl ester group into the chain, including an oligomeric mixture with a weight average number of amine groups equal to 21. The ester group in the polyamine chain was found to be sensitive to hydrolysis at neutral and alkaline pH values. The presence of an amine group near the ester group facilitates hydrolysis through coordination with a hydroxyl ion or water molecule. The catalytic action of the amine moieties is prevented by protonation of the amine at low pH values or by interaction with polymeric acid. The study of photodegradation of new polyamines by HPLC-MS showed the formation of a number of products, most of which were not considered in previous works with o-nitrobenzyl ester derivatives. The o-nitrobenzyl ester group is used in the design of gene delivery systems and other biomedical preparations as a fragment that can be degraded by light. Our results indicate that photodegradation of o-nitrobenzyl esters can produce a number of compounds whose structure and safety for living organisms must be evaluated before use. On the other hand, the discovered hydrolyzability of o-nitrobenzyl esters catalyzed by a neighboring amine group may find application in the development of drug delivery systems. We have shown that the lifetime of o-nitrobenzyl ester containing polyamines is sufficient for gene delivery. Self-degradation of the delivery agent after penetration into a living cell is a desirable case for the release of the delivered agent.

Better in the Near Infrared: Sulfonamide Perfluorinated-Phenyl Photosensitizers for Improved Simultaneous Targeted Photodynamic Therapy and Real-Time Fluorescence Imaging.

Tetraphenyloporphyrin derivatives are a useful scaffold for developing new pharmaceuticals for photodynamic therapy (PDT) and the photodiagnosis (PD) of cancer. We synthesized new sulfonamide fluorinated porphyrin derivatives and investigated their potential as photosensitizers and real-time bioimaging agents for cancer. We found that 5,10,15,20-tetrakis-[2',3',5',6'-tetrafluoro-4'-methanesulfamidyl)phenyl]bacteriochlorin (F4BMet) has intense absorption and fluorescence in the near-infrared, efficiently generates singlet oxygen and hydroxyl radicals, has low toxicity in the dark, and high phototoxicity. We increased its bioavailability with encapsulation in Pluronic-based micelles, which also improved the photodynamic effect. F4BMet exhibits pH-dependent properties (lower pH promoted its aggregation), and a GlyGly buffer was used to effectively solubilize the compound. In vitro findings with 2D cell culture were complemented with human-induced pluripotent stem cell (hiPSC)-derived organoids. F4BMet in P123 micelles showed enhanced efficacy compared to F4BMet in the GlyGly formulation. F4BMet was further evaluated in real-time bioimaging and PDT of BALB/c mice bearing CT26 tumors. After i.v. injection, the photosensitizer was visible in the tumor area 3 h after injection. The most successful therapeutic approach proved to be tumor-targeted PDT using P123-encapsulated F4BMet illuminated 24 h after administration with a light dose of 42 J/cm2, which led to a 30% long-term cure rate.

PSXI-12 Effects of Flint corn with or without high concentration of amylase and particle size on in vitro fermentation parameters, gas production and methane emission

Abstract The objective of this trial was to evaluate the fermentation parameters, gas production and dry matter (DM) disappearance in vitro of two corn hybrids with two particle sizes. A 2 × 2 factorial design study was carried out to evaluate two types of Flint corn with or without high amylase concentration (Enogen flint or Tropical Flint, respectively), and two particle sizes (1.5 or 2.5 mm). Incubations were carried out for a total period of 24 h using the automatic gas pressure system (ANKOM, RF). The ruminal liquid was combined with buffer in a 1:4 ratio respectively and each bottle received 150 mL of this mixture plus 1.5 g of DM corn sample. At the end of the 24-h period, a gas sample was taken for methane analysis, a sample was taken for short chain fatty acid (SCFA) analysis, and DM was performed on the final residue from the bottles to estimate the disappearance of DM. Data were analyzed using SAS Proc Mixed (9.4). There was no interaction effect between corn hybrid and particle size for the variables evaluated. Enogen Flint corn increased the proportion of propionate (30.7 vs. 28.1 mM/100 mM; P = 0.03) and reduced isovalerate (1.23 vs. 1.65 mM/100 mM; P = 0.01), and acetate:propionate ratio (1.85 vs. 2.11; P = 0.04), with no effect on the other fermentation variables evaluated. The particle size affected the pH of the fluid, with lower pH observed when using 1.5 mm particle size (6.64 vs. 6.70; P &amp;lt; 0.01). Regarding the disappearance of DM, Enogen Flint corn increased disappearance compared with Tropical Flint (80.8 vs. 77.5%; P &amp;lt; 0.01), and the 1.5 mm particle size also resulted in an increase in DM disappearance (81.9 vs. 76.4%; P &amp;lt; 0.01), with no interaction between the factors studied. (P = 0.80). Corn hybrids did not affect total gas production and methane production. However, the 1.5 mm particle size increased the total gas production (117.5 vs. 103.2 mL/24 h; P &amp;lt; 0.01), with no effect on methane production. In conclusion, Enogen technology optimizes the rumen fermentation process and increases corn dry matter degradability, and 1.5 mm particle size of the corn grain also increases degradability.

400 Effect of pH on in vitro ruminal metabolism of trans-10 18:1 and trans-11 18:1

Abstract Dietary C18 unsaturated fatty acids are extensively biohydrogenated by rumen microbiota into 18:0 and trans-18:1 isomers. Usually, the biohydrogenation (BH) pathways produce mostly 18:0 and trans-11 18:1 as the main intermediate. However, when fed low-forage diets that decrease the rumen pH, the main BH intermediate often is the trans-10 18:1 isomer. This change in BH, called the trans-10 shift, is associated with milk fat depression, but despite that, little is known about the triggers of the trans-10 shift and its ecological role in rumen microbiota. Microbiota stressed by low rumen pH may benefit from increased trans-18:1 availability favoring the production of the trans-18:1 isomer with a slower rate of BH. Thus, we hypothesize that at low rumen pH conditions, the BH of trans-10 18:1 will be slower than that of trans-11 18:1. We tested that with an in vitro experiment using batch incubation in Hungate tubes, replicated in 5 wk. In each run, 24 tubes were allocated at 6 treatments and 4 incubation times (0, 6, 24 and 48 h). The treatments resulted from the combination of 2 buffering solution pH (6.74 vs. 5.85) and 3 substrates: 1) Control (60 mg feed DM) 2) T10 (Control plus 1.2 mg of trans-10 18:1) and 3) T11 (Control plus 1.2 mg of trans-11 18:1). Volatile fatty acids (VFA) and long-chain fatty acids were analyzed by gas chromatography. Data were analyzed using the 2 × 3 factorial arrangement for each incubation time. Low pH resulted in less 30 to 37% DM disappearance than those with high pH at all incubation times (P &amp;lt; 0.05). The decrease in VFA with low pH was less expressive (≈17%) and only evident at 24 and 48 h incubation times. The low pH also decreased (P &amp;lt; 0.05) the BH of 18:1n-9 (less ≈47 to 53%), 18:2n-6 (less 30 to 34%) and 18:3n-3 (less 20 to 22%) at 24h and 48h incubation times, respectively. The disappearance of trans-11 18:1 was 14.6% at 6 h, 29.0% at 24 h and 32.8% at 48 h and was not affected by pH. The disappearance of trans-10 18:1 was dependent on pH. At 6 h and high pH the disappearance of both was similar, but at low pH the disappearance of trans-10 18:1 was much less (9.8%) than that of trans-11 18:1. However, at 48 h and low pH, the disappearance was similar between isomers and the disappearance of trans-10 18:1 was much greater (46.6%) than trans-11 18:1. In summary, the BH of trans-10 18:1 is less at low pH than at high pH, and this could in part explain its abundance in some practical ruminant feeding conditions. Acknowledgements: Fundação para a Ciência e a Tecnologia (FCT) funding through PTDC/CAL-ZOO/29654/2017(RumOmics), PTDC/CAL-ZOO/4515/2021(Gene2Rumen), UIDB/00276/2020 (CIISA), and LA/P/0059/2020 (AL4Animals) projects.

Influence of Eucalyptus globulus plantations on soil characteristics at different altitudinal levels

This study evaluated the influence of Eucalyptus globulus L. plantations on the physical, chemical and biological properties of the soil in three districts: Magdalena, Tingo and San Isidro del Maino. The evaluation was carried out in six plots, three with eucalyptus and three with natural forests. In each plot with eucalyptus, 10 specimens were selected to measure their dasometric characteristics. Ten soil samples were taken at the base of each specimen to evaluate the bulk density and soil characterization, replicating the sampling in the natural forest plots. Additionally, biological sampling was carried out in each plot using the Rapid Soil Sampling Protocol, with a total of five quadrats per plot. The results showed significant differences in diameter at breast height (DBH), tree height and dry biomass among the districts evaluated. Trees in Magdalena presented the highest DBH and height, with an average biomass of 934.22 kg/tree, while those in Tingo showed the lowest values, with an average biomass of 230.00 kg/tree. Diverse flora species associated with both eucalyptus and natural forests were identified, reflecting a rich biodiversity in each district. Soils with eucalyptus in Tingo showed a predominantly clay texture, while in Magdalena and San Isidro del Maino a sandy loam texture predominated. In the natural forests, the soils in Tingo were also clayey, with more varied textures in the other districts. Bulk density was higher in forest soils in Tingo and in eucalyptus soils in San Isidro del Maino. Soils under eucalyptus had lower pH and lower electrical conductivity compared to natural forest soils. In terms of nutrients, the eucalyptus soils in Tingo and Magdalena showed higher phosphorus and potassium contents, while in San Isidro del Maino, the forest soils had higher levels. In general, eucalyptus soils showed higher levels of organic carbon, organic matter and nitrogen in Tingo and Magdalena, but lower in San Isidro del Maino. Biologically, natural forest soils exhibited a higher diversity and quantity of organisms compared to eucalyptus soils, especially in San Isidro del Maino. Detritivore indices were higher in natural forests, suggesting greater soil biodiversity. This higher diversity could be associated with better soil quality in these systems, highlighting the importance of natural forests in maintaining healthy soils.

491 Processing and stomach pH influenced in vitro gastric protein solubilization kinetics in sunflower meal

Abstract The study aimed to evaluate the effect of processing and pH on gastric protein solubilization kinetics in sunflower meal (SFM) products using porcine digestion simulation model. The SFM samples were derived from diverse processing approaches: 1) dehulled-cold pressed (SFM_CP), 2) dehulled-solvent-extracted (SFM_SE), and 3) application of electrostatic separation technology on SFM_SE to generate high crude protein (CP) version (SFM_SEP). Soybean meal (SBM) was included for reference comparison (Table 1). Considering the complex factors influencing retention time, gastric pH, and pepsin secretion, the study employed multiple sampling times, and pH levels. A total of 500 mg CP equivalent of each sample (in triplicates) was mixed with 25 mL of 0.1 M phosphate buffer (pH 6.0) and 2 mL of pepsin (27 mg/mL). The pH was adjusted to either 1.5, 2.5, 3.5 or 4.5 using 1 M HCl and placed in incubator shaker (200 rpm) at 39°C. Samples were taken at 0, 30, 60, and 90 min, snap-frozen in liquid nitrogen, stored frozen, later thawed at 4°C, centrifuged (15,000 × g for 10 min) and supernatants analyzed for CP. The data were analyzed using Proc GLIMIXX in SAS while Gompertz equation was used to describe the gastric protein solubilization kinetics. The model included the fixed effects of protein source or processing, stomach pH and their interaction on the gastric CP solubility at 90 min and gastric protein solubility kinetics (A-maximum solubilized CP, Wo- initial CP solubility, Ku- solubilization rate, Ti- time to inflection). The analyzed CP SBM, SFM_CP, SFM_SE, and SFM_SEP, were 514.4, 524.4, 393.5, and 484.2 g/kg DM, respectively. Gastric CP solubility increased with lower pH and longer incubation time (P &amp;lt; 0.05), which corresponded well with the optimum pH of pepsin activity around 2. Compared with SFM, SBM had the least (P &amp;lt; 0.05) gastric CP solubility at pH 4.5 and 3.5, and the least predicted maximum gastric CP solubility (A) at pH 4.5, 3.5 and 2.5 (P &amp;lt; 0.05; Table 2). SFM_CP showed the greatest predicted initial gastric CP solubility at 0 h (Wo) and A (P &amp;lt; 0.05). Electrostatic fractionation of SFM_SE (SFM_SEP) enhanced gastric CP solubility at pH 3.5 and 2.5 and reduced the solubility time to inflection point (Ti; P &amp;lt; 0.05). In conclusion, data indicated that cold pressing SFM increased gastric CP solubility relative to solvent extraction. However, electrostatic fractionation of SFM_SE improved protein gastric solubility. While SBM remains a standard, incorporating the studied sunflower meals with their fast CP digestion kinetics in feed formulation could improve protein utilization in young animals with high stomach pH. In vivo studies, particularly on ileal amino acid digestibility, are crucial to validate these findings. Sunflower meal tables_FMN.pdf

193 Evaluation of in-dwelling pH monitoring technologies

Abstract We compared ruminal pH measurements determined using smaXtec bolus (SMAX; smaXtec Inc., Graf, Austria), Moonsyst bolus (MOON; Moonsyst International, Kinsale, Republic of Ireland), and handheld pH meter (METER; PH8500 pH/mV Meter, Apera, Columbus, OH) over time and during an ex vivo acidosis challenge. Ruminally cannulated heifers (n = 8) were used for 6 consecutive 21-d periods. On d 0, SMAX and MOON were placed in the reticulum of each heifer and continuously measured ruminal pH. On d 20 of each period, ruminal digesta samples were collected prior to feeding and again 2, 4, 6, 8, 12, 18, and 24 h post-feeding pH was measured with METER. MOON yielder lower (P &amp;lt; 0.01) pH measurements compared with SMAX and METER at all time points. From h 0 to 2 post-feeding measurements from SMAX were similar compared with METER (P = 0.54); however, measurements from SMAX tended to be greater 4 h post-feeding (P &amp;lt; 0.07) and differed at all subsequent timepoints (P &amp;lt; 0.05) compared with METER. On d 21 of each period, boli were removed and placed in a pH 4 and pH 7 solution, each for 3 h. In pH 4 solution, MOON pH measurements did not differ (P &amp;gt; 0.39) from 4 from periods 1 to 5; however, pH measured by MOON in period 6 was less (P &amp;lt; 0.01) than 4. Smaxtec pH measurements did not differ (P ≥ 0.39) from 4 during periods 2 to 5 but was greater (P &amp;lt; 0.01) than 4 in period 6. In pH 7 solution, pH measures with MOON did not differ (P &amp;gt; 0.26) from 7 for period 1 and 2 but declined in period 3 and were less than 7 from periods 4 to 6 (P &amp;lt; 0.05). In pH 7 solution, SMAX measurements varied over time and yielded greater (P &amp;lt; 0.05) than 7 for periods 2, 3, and 6. Subsequently, boli were placed in a container of strained ruminal fluid (6.5 L), and pH was measured for 1 h using SMAX, MOON, and METER. Following, 500 mL of vinegar was added to the ruminal fluid to simulate an acidosis challenge, pH was measured and change in pH detected by SMAX and MOON, relative to METER was determined. With change in pH detect by METER considered the true response, MOON provided a better measurement of the pH decrease than did SMAX, particularly during periods 1 to 3 (P &amp;lt; 0.01). Overall, pH measurements differed between SMAX, MOON, and METER. MOON and SMAX pH measurements began to drift after approximately 100 d. MOON was more accurate than SMAX in detecting a change in ruminal pH, whereas pH measurements over time were more precise for SMAX than for MOON.

Physiological resilience of intertidal chitons in a persistent upwelling coastal region

Current climate projections for mid-latitude regions globally indicate an intensification of wind-driven coastal upwelling due to warming conditions. The dynamics of mid-latitude coastal upwelling are marked by environmental variability across temporal scales, which affect key physiological processes in marine calcifying organisms and can impact their large-scale distribution patterns. In this context, marine invertebrates often exhibit phenotypic plasticity, enabling them to adapt to environmental change. In this study, we examined the physiological performance (i.e., metabolism, Thermal Performance Curves, and biomass and calcification rates) of individuals of the intertidal mollusk Chiton granosus, a chiton found from northern Peru to Cape Horn (5° to 55°S). Our spatial study design indicated a pattern of contrasting conditions among locations. The Talcaruca site, characterized by persistent upwelling and serving as a biogeographic break, exhibited lower pH and carbonate saturation states, along with higher pCO2, compared to the sites located to the north and south of this location (Huasco and Los Molles, respectively). In agreement with the spatial pattern in carbonate system parameters, long-term temperature records showed lower temperatures that changed faster over synoptic scales (1–15 days) at Talcaruca, in contrast to the more stable conditions at the sites outside the break. Physiological performance traits from individuals from the Talcaruca population exhibited higher values and more significant variability, along with significantly broader and greater warming tolerance than chitons from the Huasco and Los Molles populations. Moreover, marked changes in local abundance patterns over three years suggested population-level responses to the challenging environmental conditions at the biogeographic break. Thus, C. granosus from the Talcaruca upwelling zone represents a local population with wide tolerance ranges that may be capable of withstanding future upwelling intensification on the Southern Eastern Pacific coast and likely serving as a source of propagules for less adapted populations.

Pectin-Chitosan Hydrogel Beads for Delivery of Functional Food Ingredients.

A common challenge in hydrogel-based delivery systems is the premature release of low molecular weight encapsulates through diffusion or swelling and reduced cell viability caused by the low pH in gastric conditions. A second biopolymer, such as chitosan, can be incorporated to overcome this. Chitosan is usually associated with colonic drug delivery systems. We intended to formulate chitosan-coated pectin beads for use in delaying premature release of the encapsulate under gastric conditions but allowing release through disintegration under intestinal conditions. The latter is of utmost importance in delivering most functional food ingredients. Therefore, this study investigated the impact of formulation and process conditions on the size, sphericity, and dissolution behavior of chitosan-coated hydrogel beads prepared by interfacial coacervation. The size and sphericity of the beads depend on the formulation and range from approximately 3 to 5 mm and 0.82 to 0.95, respectively. Process conditions during electro-dripping may be modulated to tailor bead size. Depending on the voltage, bead size ranged from 1.5 to 4 mm. Confocal laser scanning microscopy and scanning electron microscopy confirmed chitosan shell formation around the pectin bead. Chitosan-coated beads maintained their size and shape in simulated gastric fluid but experienced structural damage in simulated intestinal fluid. Therefore, they represent a novel delivery system for functional food ingredients.

Temperature effects on the electrical conductivity of K‐feldspar

AbstractK‐feldspar, which constitutes about 60 of the Earth's crust, is crucial for understanding electrical conductivity in porous rocks. Its electrical properties are vital for applications in ceramics, electrical insulation and conductive polymers. In this work, we study the time evolution of electrical conductivity of K‐feldspar‐rich rocks with varying temperatures, at high and low pH, which has been studied through simulation using time domain random walk. Random walkers, mimicking ions in transport, move in accordance with appropriate hydrodynamic equations, dissolution and precipitation kinetics. Electrical conductivity has been calculated considering variations in the parameters of temperature, fluid pH and the abundance of K‐feldspar in rocks. Electrical conductivity is found to increase with temperature up to a critical value, after which it decreases. The sharpness of the rise and fall in electrical conductivity is quantified through a measure defined as the conductivity quality factor . We find that increases with a decrease in the availability of K‐feldspar mineral. Our simulated results of electrical conductivity show a good match with the experimental trends reported.

Deciphering the work function induced local charge regulation towards activating an octamolybdate cluster-based solid for acidic water oxidation.

The advancement of highly robust and efficient electrocatalysts for the oxygen evolution reaction (OER) under acidic conditions is imperative for the sustainable production of green hydrogen. In accomplishing sustainable and sturdy electrocatalysts for oxygen evolution at low pH, the challenge is tough for non-iridium/ruthenium-based electrocatalysts. This study elaborates on the intrinsic alterations in electronic arrangements and structural disorder upon the precise activation of an octamolybdate cluster-based solid [{Cu(pz)4}2Mo8O26]·2H2O through room temperature grinding with rGO (reduced graphene oxide), resulting in enhanced conductivity, stability, and activity of the electrocatalyst towards the acidic OER without employing any benchmark metal ion (Ru or Ir). Additionally, the work function of the composites was found to be low compared to that of pristine polyoxometalates (POMs), indicative of the improved conducive behavior, which is lacking in the POM structure. The catalyst displays a notably reduced overpotential of 185 mV to achieve a current density of 10 mA cm-2, coupled with significant stability lasting 24 hours at a higher current density of 100 mA cm-2. These findings propose the manipulation of crystalline POMs with highly conductive non-metallic elements to facilitate superior water oxidation at lower pH levels which can help in the production of green hydrogen.