Search

The experiment aimed to establish a method for quantitatively measuring the concentration of bacterial endotoxins in cat food using the dynamic turbidity method. Bacterial endotoxins in cat food samples were extracted with water, centrifuged, filtered, and the filtrate was appropriately diluted. Quantitative determination was carried out using the dynamic turbidity method on a bacterial endotoxin measuring instrument. The results showed good linearity of bacterial endotoxin within the range of 0.040 to 5.000 EU/mL (correlation coefficient r=-0.995 3, >0.980). The standard curve was effective, and the relative standard deviation (RSD) of repeated measurements ranged from 8.9% to 14.0% ( n=6). The recovery rates of interference tests were between 50% and 200% when the dilution factor was ≥1 000. The limit of quantification (LOQ) of the method was determined as 0.04 EU/mg. The study indicates that the method is simple, reliable, accurate, and exhibits good reproducibility, making it effective for detecting bacterial endotoxin content in cat food samples, with promising application prospects. [ABSTRACT FROM AUTHOR]

The unique thermogenic capacity of brown adipocyte makes it an attractive target for antiobesity treatments. Several epigenetic regulators can control brown adipocyte development. In this study, we show that SIRT5, a member of the sirtuins, is required for brown adipocyte differentiation and essential for brown adipogenic gene activation in vitro. Furthermore, we find out that knockdown of SIRT5 reduces intracellular α-ketoglutarate concentration, which leads to elevated H3K9me2 and H3K9me3 levels at promoter regions of Pparγ and Prdm16 loci. Finally, we discover that SIRT5 knockout mice on the Sv129 background exhibit less browning capacity in subcutaneous white adipose tissue compared with controls and show apparent cold intolerance, suggesting that SIRT5 can modulate the browning process in vivo. Thus, our study uncovers a new biological function of SIRT5 in brown adipocyte differentiation and a mechanism by which SIRT5 regulates brown adipogenic gene activation at least partly through an indirect effect on histone modifications. Our study extends the linkage between epigenetics and cell differentiation. [ABSTRACT FROM AUTHOR]

AMP-activated protein kinase (AMPK) is an energy sensor of metabolism that is an attractive therapeutic target for type 2 diabetes mellitus and metabolic syndrome. Using a homogeneous scintillation proximity assay (SPA), we identified a new small-molecule AMPK activator, ZLN024, which allosterically stimulated active AMPK heterotrimers and the inactive α1 subunit truncations α1 (1–394) and α1 (1–335) but not α1 (1–312). AMPK activation by ZLN024 requires the pre-phosphorylation of Thr-172 by at least one upstream kinase and protects AMPK Thr-172 against dephosphorylation by PP2Cα. ZLN024 activated AMPK in L6 myotubes and stimulated glucose uptake and fatty acid oxidation without increasing the ADP/ATP ratio. ZLN024 also activated AMPK in primary hepatocytes, decreased fatty acid synthesis and glucose output. Treatment of db/db mice with 15 mg/kg/day ZLN024 improved glucose tolerance; liver tissue weight, triacylglycerol and the total cholesterol content were decreased. The hepatic transcriptional level of G6Pase, FAS and mtGPAT were reduced. The transcription of genes involved in fatty acid oxidation and the mitochondrial biogenesis of muscle tissue were elevated. The ACC phosphorylation was increased in muscle and liver. This study provides a novel allosteric AMPK activator for functional study in vitro and in vivo and demonstrates that AMPK allosteric activators could be a promising therapeutic approach for type 2 diabetes mellitus and metabolic syndrome. [ABSTRACT FROM AUTHOR]

Heterogeneousreactions on mineral aerosols remain an importantsubject in atmospheric chemistry because of their role in alteringthe properties of particles and the budget of trace gases. Yet, therole of coadsorption of trace gases onto mineral aerosols and potentialsynergistic effects are largely uncertain, especially synergisticeffects between inorganic and organic gas-phase pollutants. In thisstudy, synergistic effects between HCOOH and SO2were investigatedfor the first time using in situ diffuse-reflectance infrared Fouriertransform spectroscopy (DRIFTS). It was found that the heterogeneousreaction of HCOOH is hindered significantly by coexisting SO2. The total amount of formate decreased, whereas the total amountof sulfate was not affected during coadsorption on the surface ofα-Fe2O3. Futhermore, part of the formateon the surface was catalytically decomposed to CO2by α-Fe2O3with the help of SO2. These resultssuggest a possible mechanism for the observed correlations betweensulfate and carboxylate in the atmosphere. [ABSTRACT FROM AUTHOR]

Despite increased awareness of the role played by heterogeneousreactions of formic acid on mineral aerosol, the experimental determinationof how these atmospheric reaction rates vary with temperature remaina crucially important part of atmosphere science. Here we report thefirst measurement of heterogeneous uptake of formic acid on α-Al2O3as a function of temperature (T= 240–298 K) at ambient pressure using diffuse reflectanceinfrared Fourier transform spectroscopy (DRIFTS). From the analysisof the spectral features, crystalline HCOOH was identified at lowtemperature besides common product (formate ions) on the surface.It was also interesting to find that crystalline HCOOH can continueto react with α-Al2O3. The reaction mechanismsat both room and low temperature were discussed. Furthermore, thereactive uptake coefficients were acquired and found to increase withdecreasing temperature. Finally, the atmospheric lifetime of formicacid because of heterogeneous loss on mineral aerosol was estimatedat temperatures related to the upper troposphere. [ABSTRACT FROM AUTHOR]

Abstract: Two novel adsorbents to remove excess arsenate and arsenite in the drinking water were prepared for the first time by grafting monoamine and diamine, respectively, and then coordinating Fe3+ on silica gel that was obtained using sol–gel method with two-step acid-base catalysis. It was found that both adsorbents had mesoporous structure, large specific surface, and high amino and iron content according to N2 adsorption isotherms, FTIR, XPS, and NMR analysis. The removal ability and adsorption rate of the adsorbents were very high for both As(V) and As(III). Langmuir and Freundlich models were used to fit the adsorption isotherm and investigate the adsorption mechanism. The effects of chloride and sulfate anion on the removal of arsenate and arsenite for the two adsorbents were also studied. [Copyright &y& Elsevier]