Acid Generation Research Articles

Thermophilic Dark Fermentation for Simultaneous Mixed Volatile Fatty Acids and Biohydrogen Production from Food Waste

Food waste is categorized as organic solid waste, which has a negative impact on environmental sustainability. Food waste was simultaneously used for the feasible generation of mixed volatile fatty acids (VFAs) and bio-hydrogen by deploying dark fermentation. Original anaerobic digested sludge was prepared via the shock technique with 50 g/L glucose under thermophilic temperature (55 °C). The pretreated inoculum was found capable of converting 10 g VS/L food waste to hydrogen with a rather high yield of 135.2 ± 7 mL H2/VSadded. The effect of various concentrations of food waste, including 10.2, 16.3, 20.3, and 26.4 g VS/L, on mixed VFAs production was subsequently carried out in batch dark fermentation. The highest butyric acid concentration (5.26 ± 0.22 g/L) in soluble metabolites was obtained from batch dark fermentation with 26.4 g VS/L of food waste. The dominant Clostridium thermobutyricum, Clostridium sporogenes, and Octadecobacter sp. found in the batch of dark fermentation of food waste could confirm the effectiveness of the load shock pretreatment method for inoculum preparation. The continuous stirred tank reactor (CSTR) inoculated with mixed cultures, also prepared via the load shock pretreatment method and without the addition of external nutrients, was operated by feeding 26.4 g VS/L food waste at the kinetically designed HRT for 4 days, corresponding to an organic loading rate (OLR) of 7.6 g VS/L·d. Under steady state conditions, promising butyric acid (5.65 ± 0.51 g/L)-rich mixed VFAs were achieved along with the hydrogen yield of 104.9 ± 11.0 mL-H2/g VSadded, which is similar to the upper side of the previously reported yields (8.8 ± 0.6–103.6 ± 0.6 mL-H2/g VS).

Estimation of Caffeine and Vitamin B-Complex (Vitamin B2, B3, B5 and B6) Constituents of Selected Energy Drinks

Vitamins are important nutrients that are contained in food and carry out distinct and important bodily tasks that are required for sustaining good health. A xanthine alkaloid known as caffeine is widely distributed in natural plant sources such as coffee, cocoa beans, cola nuts, and tea leaves. Additionally, it is a raw material in several drinks. Its usage increases blood pressure, diuresis, blood sugar, generation of stomach acid and pepsin, plasma levels of fatty acids, cortisol, and epinephrine, intraocular pressure, and calcium loss, which causes bone loss. The phrase "energy drinks" refers to beverages that advertise that they will give you an energy boost, which has led to an increase in the popularity of "energy drinks" that include caffeine. The caffeine and vitamin B-complex concentrations of a few different energy drinks were tested and compared in this study project. Samples of ten (10) different energy drink brands were chosen at random from Nkwo Ogbe Market in Ihiala, and their caffeine and vitamin B1, B2, B6, and B12 concentrations were determined using a spectrophotometric technique. The findings revealed that caffeine concentrations varied from 1.11 mg/L to 2.13 mg/L, and that vitamin B1 in energy drinks had the lowest value (0.014 mg/kg). All samples of energy drinks had caffeine levels below the 400 mg/L benchmark set by the National Agency for Food and Drug Administration and Control (NAFDAC). In order to avoid negative consequences, it is important to monitor any decrease in intake of these beverages because other criteria, such as aspartame and sugar, were also often below the established levels.

Biorecovery of rare earth elements from fluorescent lamp powder using the fungus Aspergillus niger in batch and semicontinuous systems

Rare earth elements (REE) are essential in the manufacture of high-technology goods. Tons of wastes containing REE are yearly accumulated; however, environmentally friendly recycling methods are poorly studied. The use of heterotrophic microorganisms could be particularly relevant in the bioleaching of wastes transforming insoluble REE-bearing compounds into more soluble forms which are directly and/or indirectly involved in their metabolism. In this study, bioleaching of rare earth elements from fluorescent phosphor powder in fluorescent tubes using Aspergillus niger CECT2807 was investigated. Bioleaching experiments were performed in batch cultures at 1% pulp density. The concentrations in solution reached 122 mg/l of Y, 8.50 mg/l of Eu, 0.95 mg/l of Ce, 0.40 mg/l of Tb and 1.11 mg/l of La, after 7 days. Then, REE precipitated due to the generation of oxalic acid by the fungus. The residues generated were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) and the lamp powder biotransformation was evidenced. Additionally, semicontinuous experiments were conducted and evidenced significant increase of REE dissolution rate in static conditions. The amount of extracted REE under static conditions reached 16.5 mg of Y and 0.75 mg of Eu per gram of fluorescent lamp powder.

Review of the clinical development of fexuprazan for gastroesophageal reflux-related disease.

Proton pump inhibitors (PPIs) are a mainstay treatment for acid peptic disorders such as gastroesophageal reflux disease (GERD). Although PPIs are considered first-line medications for acid suppression, they have notable limitations such as requiring acid-mediated activation, short half-life and duration of action, and metabolic variability. Fexuprazan is a newly developed potassium-competitive acid blocker (P-CAB), which inhibits acid generation and secretion in a competitive and reversible manner. Fexuprazan, like other P-CABs, has significantly different pharmacodynamic and pharmacokinetic properties than PPIs with potential advantages including rapid, robust, and durable acid suppression, lack of CYP2C19 metabolism, independence from food intake, and no requirement for activation into an active form. Completed clinical trials of fexuprazan have demonstrated comparable efficacy to PPIs for the healing of erosive esophagitis and relief of GERD-related esophageal symptoms without concerning safety signals. Ongoing clinical trials are evaluating fexuprazan for the prevention of NSAID-induced peptic ulcer disease, non-erosive GERD, and acute and chronic gastritis, as well as healing efficacy and maintenance of erosive esophagitis (EE). Fexuprazan is approved in South Korea for the treatment of EE and at the time of this writing is being considered for regulatory approval in several other countries. In this article, we summarize and discuss the pharmacology, efficacy, and safety of fexuprazan.

PREVALENCE RATE OF ESBL AMONG ENTEROBACTERIACEAE ISOLATED FROM UTI PATIENTS IN SULAIMANI PROVINCE

Background Extended-Spectrum β-Lactamase are enzymes that provide resistance against third-and fourth generation Cephalosporins and Monobactams, and they are distributed among the Enterobacteriaceae family.
 Objectives To describe the prevalence of Extended-Spectrum β-Lactamase among Enterobacteriaceae causing urinary tract infections in Sulaimani province.
 Patients and MethodsOne hundred bacterial isolates of Enterobacteriaceae from patients with urinary tract infections attending Smart Hospital (inpatients and outpatients). Urine samples were inoculated onto different culture media. Colony morphology, gram staining, and BD Phoenix™ system were used for bacterial identification. Antibiotic profile and Extended-Spectrum β-Lactamase were observed phenotypically by antibiotic profile results, double disk synergy test, and confirmed by combined disk test methods and BD Phoenix™ system.
 ResultsOut of one hundred isolates of Enterobacteriaceae, Escherichia coli was the commonest isolate (89), followed by Klebsiella pneumoniae (10) and one isolate of Proteus mirabilis. According to the antibiotic profile, the most effective antibiotic among all three isolates was Imipenem and Nitrofurantoin, while the most resistant antibiotic was Nalidixic acid and third generation Cephalosporin. The prevalence rate of Extended-Spectrum β-Lactamase -producing Enterobacteriaceae was 69% by the screening tests and 48% by the confirmatory tests.
 ConclusionIn this study, Extended-Spectrum β-Lactamase prevalence was shown to be at an alarming rate that must be considered. The high priority of public health justifies further investigation to properly establish annual surveillance systems that can aid in selecting an appropriate antibiotic upon ESBL detection.

Short-Term Changes in Aroma-Related Volatiles in Meat Model: Effect of Fat and D. hansenii Inoculation.

This study assessed the effect of replacing pork lard with coconut oil and Debaryomyces hansenii inoculation on the biotransformation of amino acids into volatile compounds in a meat model system. Yeast counts, solid-phase microextraction, and gas chromatography/mass spectrometry were used to assess yeast growth and volatile production, respectively. Yeast growth was confirmed until 28 d, although the volatile profile changed until 39 d. Forty-three volatiles were quantified, and their odor activity values (OAVs) were calculated. The presence of fat and yeasts contributed to differences in volatiles. In pork lard models, a delayed formation of lipid-derived aldehyde compounds was observed, whereas in coconut oil models, the generation of acid compounds and their respective esters was enhanced. Yeast activity affected amino acid degradation, which produced an increase in branched-chain aldehydes and alcohols. The aroma profile in the coconut models was influenced by hexanal, acid compounds, and their respective esters, whereas in pork lard models, aroma was affected by methional (musty, potato) and 3-methylbutanal (green, cocoa). The yeast inoculation contributed to the generation of 3-methylbutanoic acid (cheesy) and phenylethyl alcohol (floral). The type of fat and yeast inoculation produced a differential effect on the aroma.

Outstanding productions of peroxymonosulfuric acid combining tailored electrode coating and 3D printing

In this work, the combination of a tailored design of electrode and electrochemical cell to produce peroxymonosulfuric acid (PMSA), also known as Caro's acid, is evaluated. For the electrode, a customized coating of BDD was deposited onto a niobium substrate. This electrode exhibited a good reproducibility and efficiency in the production of PMSA, thus promoting direct oxidation of sulfuric acid into Caro's acid and preventing the action of scavengers. The electrochemical cell was manufactured after the application of computer-aided design (CAD) combined with computational fluid-dynamics (CFD) simulation and 3D printing. The prototype, with an area of 25sqcm and a designed flowrate of 48 L/h, has been characterized with the evaluation of mass transfer coefficients and RDT curves, which demonstrate an outstanding performance with mass transport coefficients over 3·10−5 m s−1 without turbulence promoter. The cell equipped with the electrodes was tested in the production of Caro's acid enabling a remarkable production of 200 mM of peroxymonosulfuric acid in discontinuous operation mode with a coulombic efficiency (57.2 %) and energy Efficiency (10.67 mmolA−1 h−1). These values outperform the previous state-of-the-art works done in the field for undivided cells operated in discontinuous mode. The results obtained were successfully fitted to a phenomenological model for the generation of Caro's acid.

Pd-M (M = Ni, Co) Bimetallic Catalysts with Tunable Composition for Highly Efficient Electrochemical Formic Acid Oxidation

Bimetallic Pd-based catalysts for formic acid oxidation (FAO) are one of the most promising anode materials for the next generation of direct formic acid fuel cells (DFAFC). It is imperative to develop a simple strategy for preparing efficient, stable, and clean nanoparticle catalysts. Herein, we prepared a series of Pd, PdNi, and PdCo nanoparticle catalysts using the nanoparticle beam composite deposition system, which revealed good catalytic activity and stability in the process of FAO. The incorporation of Ni or Co prevents the adsorption of active intermediates and the accumulation of toxic intermediates in the process of FAO. Therefore, more Pd active centers can be used to decompose formic acid directly by dehydrogenation. The results indicate that PdNi-2 (Pd0.9Ni0.1) and PdCo-3 (Pd0.89Co0.11) catalysts exhibit the optimal catalytic performance, with the mass activity of 1491.5 A g−1Pd and 1401.7 A g−1Pd, respectively, which is 2.1 and 2 times that of the pure Pd sample. By optimizing the rate of Pd to transition metal M (Ni, Co), a high-performance Pd-based catalyst was obtained through their synergistic effect, which provides a new approach for designing efficient anode catalysts for DFAFCs.

The role of hydrochloric acid pretreated activated carbon in chain elongation of D-lactate to caproate: Adsorption and facilitation

Medium chain fatty acids (MCFA) generation is attracting growing interest due to fossil fuel depletion. To promote the production of MCFA, especially caproate, hydrochloric acid pretreated activated carbon (AC) was introduced into chain elongation fermentation. In this study, the role of pretreated AC on caproate production was investigated using lactate and butyrate as electron donor and electron acceptor, respectively. The results showed that AC did not improve the chain elongation reaction at beginning but promoted the caproate production at later stage. The addition of 15 g/L AC facilitated reactor reaching the peak of caproate concentration (78.92 mM), caproate electron efficiency (63.13%), and butyrate utilization rate (51.88%). The adsorption experiment revealed a positive correlation between the adsorption capacity of pretreated AC and the concentration as well as the carbon chain length of carboxylic acids. Moreover, the adsorption of undissociated caproate by pretreated AC contributed to a mitigated toxicity towards microorganisms, thereby facilitating the production of MCFA. Microbial community analysis revealed an increasing enrichment of key functional chain elongation bacteria, including Eubacterium, Megasphaera, Caproiciproducens, and Pseudoramibacter, but a suppression on acrylate pathway microorganism Veillonella, as the dosage of pretreated AC increasing. The findings of this study demonstrated the substantial impact of the adsorption effect of acid-pretreated AC on promoting caproate production, which would aid to the development of more efficient caproate production process.

Reagentless Dissolution and Quantification of Particulate Lead in Tap Water via Membrane Electrolysis.

The presence of particulate Pb in tap water has been a limiting factor in the design of accurate and portable platforms for quantifying this toxic metal. Convenient and affordable electrochemical techniques are blind toward particulate species and thus require addition of reagents and additional chemical processing such as sample acidification. This study describes the fundamentals and the first use of membrane electrolysis for the reagentless sample preparation of tap water for the detection of particulate Pb contaminants. Membrane electrolysis allows for the in-situ generation of nitric acid, which, in combination with anodic stripping voltammetry, provides a powerful tool for the accurate and reagent-free detection of Pb2+. The configuration of the setup allows for its semi-autonomous operation and requires minimal attention, making electrochemical methods more suitable and accessible for continuous measurements of particulate contaminants in tap-water. The voltammetric response is linear in the range of 24.1-398 nM of Pb, which covers the action level of 48 nM suggested by the World Health Organization.

Multi‐emitting fluorescent system–assisted lab‐in‐a‐syringe device for on‐site and background‐free detection of 2,4‐dichlorophenoxyacetic acid

AbstractHerbicide residuals have posed severe threat to food safety and public health; thus, the development of smart, portable, efficient, and accurate on‐site detection system is in urgent demand. Here, a multi‐emitting fluorescent system‐assisted lab‐in‐a‐syringe (LIS) device was developed for the on‐site and background‐free determination of 2,4‐dichlorophenoxyacetic acid (2,4‐D). 2,4‐D‐responsive cascade reactions were constructed: 2,4‐D could specifically suppress alkaline phosphatase (ALP) activity and restrain the generation of ascorbic acid (AA), MnO2 nanosheets would oxidize AA into dehydroascorbic acid that subsequently reacts with o‐phenylenediamine (OPD) to generate blue‐emission product (λem, 435 nm), whereas remained MnO2 nanosheets and OPD further produced yellow‐emission product (λem, 570 nm). Red‐emission carbon dots (RCDs, λem, 680 nm), synthesized via the solvothermal treatment of cilantro, were introduced to construct a multi‐emitting fluorescent system. Then, four paper pads, respectively, dropped with ALP, sodium l‐ascorbyl‐2‐phosphate, MnO2 nanosheets + RCDs, and OPD were held into reusable plastic filters and assembled paper‐based LIS device to trigger cascade reactions (total analysis time, 65 min) and eliminate background interference. As a result, with the support of color recognizer application in smartphone, fluorescent color on detection pads from blue–purple to red to yellow was achieved for the sensitive and visual detection of 2,4‐D with LOD of 5.0 μg L−1, recoveries of 94.6%–106.8%, and relative standard deviations of 2.3%–6.8%. Obviously, this strategy provides a robust, visual, and background‐free platform for 2,4‐D detection, which expands application prospects in the field of herbicide analysis.

Coordination environment tuning of Ni-Sn catalysts by glu-carbon to optimize cellulose hydrogenolysis to oxygenated chemicals

Bimetallic alloys are currently being developed as promising catalysts for the utilization of biomass. However, further study is required to understand their multifunctionality and to conduct computational screening. In this work, we synthesized Ni-Sn alloy-rich catalysts using glucose molecules to assist in cellulose hydrogenolysis. Our experimental findings demonstrated successful synthesis of Ni-Sn alloys (Ni3Sn2 and Ni3Sn4) with strong interactions and Lewis acid generation. Upon closer inspection, we discovered that glucose not only released reducing gas but also facilitates the formation of glu-carbon during calcination, which enhanced metal dispersion and modified the surface amphipathy. The multifunctional Ni-Sn catalyst directly converted to polyols and ketols in one-pot reaction, yielding a remarkable 54.6% of C2,3 polyols and 12.3% of C3,4 ketols. Density functional theory (DFT) provided the insight into the role of Ni3Sn2 and Ni3Sn4 alloys in producing C2-4 oxygenated chemicals. Specially, the Ni3Sn4 (20-1) facet enhanced the adsorption of key C2 intermediate through Ni-O bond formation via electrons transformation, while Ni3Sn2 (1-10) contributed to the catalytic activity for C3 intermediate. Furthermore, these alloy-rich catalysts exhibited superior thermal stability, effectively by preventing metal etching. This work presented a novel fabrication strategy for alloy-rich catalysts and provided an understanding of intrinsic mechanism underlying the catalytic roles of NixSny alloys in the hydrothermal conversion.

Antimicrobial susceptibility and integrons detection among extended-spectrum β-lactamase producing Enterobacteriaceae isolates in patients with urinary tract infection.

Integrons are bacterial mobile genetic components responsible for mediating the antibiotic resistance process by carrying and spreading antimicrobial resistance genes among bacteria through horizontal gene transfer. This cross-sectional hospital-based study aimed to find the prevalence of antibiotic resistance patterns and to detect integrons classes (I, II, and III) among bacterial isolates in patients with urinary tract infections (UTI) in Sulaimani, Iraq. Mid-stream urine samples (no. = 400) were collected from patients with UTI at three different Hospitals from Sulaimani, Iraq, between September 2021 to January 2022. Urine samples were cultured on various agar media, and grown bacteria were isolated. Antibiotic susceptibility test (AST) and an extended-spectrum β-lactamase (ESBL) screen were done for isolated bacteria. Then, integrons classes were screened using conventional PCR with gene sequencing and uploaded to the National Center for Biotechnology Information (NCBI). The frequency rate of Enterobacteriaceae was 67.03% among positive urine cultures. E. coli (no. = 86) and Klebsiella pneumoniae (no. = 32) isolates were identified. The most sensitive antibiotics were the carbapenem group (85.3%) and nitrofurantoin (NFN) (64.2%), while the most resistant antibiotics were nalidixic acid (NA) and 3rd generation cephalosporin. The occurrence rate of ESBL was 56.6% with a predominance of class I integron (54.2%), then class II (15.8%) and no positive record for class III integron were observed. Most bacterial isolates from patients with UTI produced class I and II integrons genes with favourable ESBL properties.

Electro-acupuncture promotes gut motility and alleviates functional constipation by regulating gut microbiota and increasing butyric acid generation in mice

ObjectiveAbnormalities in the gut microbiota and intestinal short-chain fatty acid (SCFA) levels are implicated in the pathogenesis of functional constipation (FC). Electro-acupuncture (EA) has been shown to improve constipation-related symptoms and rebalance the gut microbiota. However, it is currently unknown whether the gut microbiota is a key mechanistic target for EA or how EA promotes gut motility by regulating the gut microbiota and SCFAs. Therefore, we assessed the effects of EA in FC mice and pseudo-germfree (PGF) mice to address these questions. MethodsForty female Kunming mice were randomly separated into a normal control group (n = 8), an FC group (n = 8), an FC + EA group (n = 8), a PGF group (n = 8) and a PGF + EA group (n = 8). The FC group and FC + EA group were treated with diphenoxylate to establish the FC model; the PGF group and PGF + EA group were given an antibiotic cocktail to initiate the PGF model. After maintaining the model for 14 d, mice in the FC + EA and PGF + EA groups received EA stimulation at the ST25 and ST37 acupoints, once a day, 5 times per week, for 2 weeks. Fecal parameters and intestinal transit rate were calculated to assess the efficacy of EA on constipation and gastrointestinal motility. Colonic contents were used to quantify gut microbial diversity using 16S rRNA sequencing, and measure SCFA concentrations using gas chromatography-mass spectrometry. ResultsEA significantly shortened the first black stool defecation time (P < 0.05) and increased the intestinal transit rate (P < 0.01), and fecal pellet number (P < 0.05), wet weight (P < 0.05) and water content (P < 0.01) over 8 h, compared with the FC group, showing that EA promoted gut motility and alleviated constipation. However, EA treatment did not reverse slow-transit colonic motility in PGF mice (P > 0.05), demonstrating that the gut microbiota may play a mechanistic role in the EA treatment of constipation. In addition, EA treatment restored the Firmicutes to Bacteroidetes ratio and significantly increased butyric acid generation in FC mice (P < 0.05), most likely due to the upregulation of Staphylococcaceae microorganisms (P < 0.01). ConclusionEA-mediated resolution of constipation occurs through rebalancing the gut microbiota and promoting butyric acid generation.Please cite this article as: Xu MM, Guo Y, Chen Y, Zhang W, Wang L, Li Y. Electro-acupuncture promotes gut motility and alleviates functional constipation by regulating gut microbiota and increasing butyric acid generation in mice. J Integr Med. 2023; Epub ahead of print.

Plasmon-Enhanced Photocatalytic CO2 Reduction for Higher-Order Hydrocarbon Generation Using Plasmonic Nano-Finger Arrays.

The carbon dioxide reduction reaction (CO2RR) is a promising method to both reduce greenhouse gas carbon dioxide (CO2) concentrations and provide an alternative to fossil fuel by converting water and CO2 into high-energy-density chemicals. Nevertheless, the CO2RR suffers from high chemical reaction barriers and low selectivity. Here we demonstrate that 4 nm gap plasmonic nano-finger arrays provide a reliable and repeatable plasmon-resonant photocatalyst for multiple-electrons reactions: the CO2RR to generate higher-order hydrocarbons. Electromagnetics simulation shows that hot spots with 10,000 light intensity enhancement can be achieved using nano-gap fingers under a resonant wavelength of 638 nm. From cryogenic 1H-NMR spectra, formic acid and acetic acid productions are observed with a nano-fingers array sample. After 1 h laser irradiation, we only observe the generation of formic acid in the liquid solution. While increasing the laser irradiation period, we observe both formic and acetic acid in the liquid solution. We also observe that laser irradiation at different wavelengths significantly affected the generation of formic acid and acetic acid. The ratio, 2.29, of the product concentration generated at the resonant wavelength 638 nm and the non-resonant wavelength 405 nm is close to the ratio, 4.93, of the generated hot electrons inside the TiO2 layer at different wavelengths from the electromagnetics simulation. This shows that product generation is related to the strength of localized electric fields.

MINERALOGICAL AND GEOCHEMICAL STUDY OF ANDESITE ALTERATION ZONE IN BUKIT MANTRI GOLD MINE, BALUNG, SABAH

This paper highlights the geochemical compositions and mineralogy of the alteration zone of the andesitic host rock and volcanic breccia in Bukit Mantri area near Balung, Tawau, Sabah, where a gold mining project is now taking place. Minerals identified by XRD analysis include quartz, pyrite, K-feldspar, muscovite, chlorite, kaolinite, hematite, and goethite, while thin section analysis confirms the abundance of pyrite. XRF and ICP-OES analyses suggest a significant concentration of SO3, Cu, Pb, Zn and As, with average values of 2.68wt%, 254μg/g, 236.9μg/g, 232.9μg/g, and 30.6μg/g, respectively, in the hydrothermally altered andesite. The widespread presence of pyrite and higher concentration of SO3 provide insights for environmental control for its higher acidity generation potential. Meanwhile, secondary minerals such as iron and aluminium oxides and silicate minerals may provide acid buffers and reduce the dispersion of constituents.

In vitro simulated fecal fermentation of mixed grains on short-chain fatty acid generation and its metabolized mechanism

In vitro simulated digestion and fecal fermentation were performed to investigate the influence of mixed grains on gut microbes. In addition, the key metabolic pathways and enzymes associated with short-chain fatty acids (SCFAs) were explored. The mixed grains exhibited an observable regulatory effect on the composition and metabolism of intestinal microorganisms, especially in probiotics, such as Bifidobacterium spp., Lactobacillus spp., and Faecalibacterium spp. WR (wheat + rye), WB (wheat + highland barley) and WO (wheat + oats) tended to generate lactate and acetate, which are related to Sutterella, Staphylococcus, etc. WQ (wheat + quinoa) induced high propionate and butyrate accumulation by consuming lactate and acetate, mainly through Roseburia inulinivorans, Coprococcus catus and Anaerostipes sp., etc. Moreover, bacteria enriched in different mixed grain groups regulated the expression of pivotal enzymes in metabolic pathways and then affected the generation of SCFAs. These results provide new knowledge on the characteristics of intestinal microbial metabolism in different mixed grain substrates.

Gentamicin alleviates cholestatic liver injury by decreasing gut microbiota-associated bile salt hydrolase activity in rats

Intrahepatic cholestasis lacks effective therapeutic drugs. The gut microbiota-associated bile salt hydrolases (BSH) may be a potential therapeutic target. In this study, oral administration of gentamicin (GEN) decreased the serum and hepatic levels of total bile acid in 17α-ethynylestradiol (EE)-induced cholestatic male rats, significantly improved the serum levels of hepatic biomarkers and reversed the histopathological changes in the liver. In healthy male rats, the serum and hepatic levels of total bile acid were also decreased by GEN, the ratio of primary to secondary bile acids, and conjugated to unconjugated bile acids was significantly increased, and the urinary excretion of total bile acid was elevated. 16S rDNA sequencing of the ileal contents revealed that GEN treatment substantially reduced the abundance of Lactobacillus and Bacteroides both of which expressed BSH. Consistently, BSH activity analysis by the generation of d5-chenodeoxycholic acid from d5-taurochenodeoxycholic acid in situ showed BSH was significantly inhibited in the ileal contents of rats treated with GEN. This finding led to an increased proportion of hydrophilic conjugated bile acids and facilitated the urinary excretion of total bile acids, thereby decreasing serum and hepatic total bile acids and reversing liver injury related to cholestasis. Our results provide important evidence that BSH can be a potential drug target for treating cholestasis.

Vitamin B6 Deficiency Induces Autism-Like Behaviors in Rats by Regulating mTOR-Mediated Autophagy in the Hippocampus.

Vitamin B6 (VB6) exhibits therapeutic effects towards autism spectrum disorder (ASD), but its specific mechanism is poorly understood. Rat dams were treated with VB6 standard, VB6 deficiency, or VB6 supplementary diet, and the same treatment was provided to their offspring, with their body weights monitored. Three-chambered social test and open field test were employed to evaluate the effect of VB6 on autism-like behaviors. Gamma-aminobutyric acid (GABA) generation and synaptic inhibition of neurons in the hippocampus of rat were detected via immunofluorescence staining, followed by the measurement of GABA concentration through high-performance liquid chromatography (HPLC). The role of VB6 in the autophagy and apoptosis of cells was determined via Western blot and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). In order to conduct rescue experiments, the inhibition of mammalian target of rapamycin (mTOR) or the activation of GABA was achieved by drug administration to the offspring rats with VB6 deficiency. As a result, no evident difference in weight was observed in the offspring with varied VB6 treatments. VB6 deficiency impaired social interaction; aggravated self-grooming and bowel frequency; decreased GABA concentration, VIAAT, GAD67, vGAT expressions, and LC3 II/LC3 I ratio; increased p62 level and p-mTOR/mTOR ratio; and promoted cell apoptosis. Inhibition of mTOR reversed the effect of VB6 deficiency on cell autophagy. GABA activation or mTOR inhibition offset the role of VB6 deficiency in autism-like behaviors and hippocampal GABA expression. Collectively, VB6 deficiency induces autism-like behaviors in rats by regulating mTOR-mediated autophagy in the hippocampus.

Pd(II)-based coordination polymer nanosheets for ratiometric colorimetric and photothermal dual-mode assay of serum alkaline phosphatase

Fabrication of a multi-signal readout assay with high sensitivity and selectivity is highly desirable for clinical and biochemical analysis, but remains a challenge due to laborious procedures, large-scale instruments, and inadequate accuracy. Herein, a straightforward, rapid, and portable detection platform based on palladium(II) methylene blue (MB) coordination polymer nanosheets (PdMBCP NSs) was unveiled for the ratiometric dual-mode detection of alkaline phosphatase (ALP) with temperature and colorimetric signal readout properties. The sensing mechanism is the ALP-catalyzed generation of ascorbic acid for competitive binding and etching PdMBCP NSs to release free MB in a quantitive means for detection. Specifically, ALP addition led to the decrease of temperature signal readout from the decomposed PdMBCP NSs under 808 nm laser excitation, and simultaneous increase of the temperature from the generated MB with a 660 nm laser, together with the corresponding absorbance changes at both wavelengths. Notably, this ratiometric nanosensor exhibited a detection limit of 0.013 U/L (colorimetric) and 0.095 U/L (photothermal) within 10 min, respectively. The reliability and satisfactory sensing performance of the developed method were further confirmed by clinic serum samples. Therefore, this study provides a new insight for the development of dual-signal sensing platforms for convenient, universal, and accurate detection of ALP.