This study aimed to investigate the changes in intestinal homeostasis and metabolism in mice after methamphetamine (MA) administration and exercise intervention. In this study, male C57BL/B6J mice were selected to establish a model of methamphetamine-induced addiction, and the gut microbiota composition, short-chain fatty acids (SCFAs), and amino acid levels were assessed by 16S rRNA, liquid chromatography-tandem mass spectrometry, and gas chromatography-tandem mass spectrometry, respectively. The results showed that 23 dominant microbiota, 12 amino acids, and 1 SCFA were remarkably higher and 9 amino acids and 6 SCFAs were remarkably lower in the exercise model group than in the control group. Among the top 10 markers with opposite trends between the exercise intervention group and model group, the differential microbiomes included Oscillibacter, Alloprevotella, Colidextribacter, Faecalibaculum, Uncultured, Muribaculaceae, and Negativibacillus; amino acids included proline; and SCFAs included isovaleric acid and pentanoic acid. Proline was negatively correlated with Negativibacillus and positively correlated with pentanoic acid. The results suggested that moderate-intensity aerobic exercise may modulate changes in the composition of the gut microbiota and the levels of amino acids and SCFAs induced by MA administration.

Mounting evidence suggests that gut microbiota can play an important role in pathophysiology of depression, but its specific molecular mechanisms are still unclear. This study was conducted to explore the associations between changes in neurotransmitters and short-chain fatty acids (SCFAs) and altered gut microbiota in depressed mice. Here, the chronic restraint stress (CRS) model of depression was built. The classical behavioral tests were conducted to assess the depressive-like behaviors of mice. The 16S rRNA gene sequence extracted from fecal samples was used to assess the gut microbial composition. Liquid and gas chromatography mass spectroscopy were used to identify neurotransmitters in hypothalamus and SCFAs in fecal samples, respectively. Finally, 29 differential bacteria taxa between depressed mice and control mice were identified, and the most differentially abundant bacteria taxa were genus Allobaculum and family Ruminococcaceae between the two groups. The acetic acid, propionic acid, pentanoic acid, norepinephrine, 5-HIAA and 5-HT were significantly decreased in depressed mice compared to control mice. Genus Allobaculum was found to be significantly positively correlated with acetic acid and 5-HT. Taken together, these results provided novel microbial and metabolic frameworks for understanding the role of microbiota-gut-brain axis in depression, and suggested new insights to pave the way for novel therapeutic methods.

Bile acids are steroids with a pentanoic acid substituent at C-17. They are the terminal products of cholesterol excretion, and play critical physiological roles in human and animals. Bile acids are easy to detect but difficult to identify by using mass spectrometry due to their poly-ring structure and various hydroxylation patterns. In this study, fragmentation pathways of 18 free and conjugated bile acids were interpreted by using tandem mass spectrometry. The analyses were conducted on ion trap and triple quadrupole mass spectrometers. Upon collision-induced dissociation, the conjugated bile acids could cleave into glycine or taurine related fragments, together with the steroid skeleton. Fragmentations of free bile acids were further elucidated, especially by atmospheric pressure chemical ionization mass spectrometry in positive ion mode. Aside from universally observed neutral losses, eliminations occurred on bile acid carbon rings were proposed for the first time. Moreover, four isomeric 5β-cholanic acid hydroxyl derivatives (3α,6α-, 3α,7β-, 3α,7α-, and 3α,12α-) were differentiated using electrospray ionization in negative ion mode: 3α,7β-OH substituent inclined to eliminate H(2)O and CH(2)O(2) groups; 3α,6α-OH substituent preferred neutral loss of two H(2)O molecules; 3α,12α-OH substituent apt to lose the carboxyl in the form of CO(2) molecule; and 3α,7α-OH substituent exhibited no further fragmentation after dehydration. This study provided specific interpretation for mass spectra of bile acids. The results could contribute to bile acid analyses, especially in clinical assays and metabonomic studies.

Background: The production of intestinal gases and fecal short-chain fatty acids (SCFAs) by infant gut microbiota may have a significant impact on their health, but information about the composition and volume of intestinal gases and SCFA profiles in preterm infants is scarce. Objective: This study examined the change of the composition and volume of intestinal gases and SCFA profiles produced by preterm infant gut microbiota in vitro during the first 4 weeks of life. Methods: Fecal samples were obtained at five time points (within 3 days, 1 week, 2 weeks, 3 weeks, and 4 weeks) from 19 preterm infants hospitalized in the neonatal intensive care unit (NICU) of Shanghai Children's Hospital, Shanghai Jiao Tong University between May and July 2020. These samples were initially inoculated into four different media containing lactose (LAT), fructooligosaccharide (FOS), 2'-fucosyllactose (FL-2), and galactooligosaccharide (GOS) and thereafter fermented for 24 h under conditions mimicking those of the large intestine at 37.8°C under anaerobic conditions. The volume of total intestinal gases and the concentrations of individual carbon dioxide (CO2), hydrogen (H2), methane (CH4), and hydrogen sulfide (H2S) were measured by a gas analyzer. The concentrations of total SCFAs, individual acetic acid, propanoic acid, butyric acid, isobutyric acid, pentanoic acid, and valeric acid were measured by gas chromatography (GC). Results: The total volume of intestinal gases (ranging from 0.01 to 1.64 ml in medium with LAT; 0-1.42 ml with GOS; 0-0.91 ml with FOS; and 0-0.44 ml with FL-2) and the concentrations of CO2, H2, H2S, and all six fecal SCFAs increased with age (p-trends < 0.05). Among them, CO2 was usually the predominant intestinal gas, and acetic acid was usually the predominant SCFA. When stratified by birth weight (<1,500 and ≥1,500 g), gender, and delivery mode, the concentration of CO2 was more pronounced among infants whose weight was ≥1,500 g than among those whose weight was <1,500 g (p-trends < 0.05). Conclusions: Our findings suggested that the intestinal gases and SCFAs produced by preterm infant gut microbiota in vitro increased with age during the first 4 weeks of life.

Concentrated cream (CC) is a dairy product containing more than 60% milk fat. CC has a very short shelf life because it is made from unripe cream. The present study aims to determine how packaging with reducing gas (H2) and nitrogen (N2) affects the quality properties and shelf life of CC. For this purpose, lipolysis, oxidation, color, microbiological, and free fatty acid development and the fatty acid composition of modified atmosphere packaged (MAP) CC samples were studied for 28 days. For MAP1, 96% N2 + 4% H2 was used, and for MAP2, 100% N2 and air was used for the control group. During storage, MAP1 samples remained at lower lipolysis (ADV and FFA) and oxidation levels than MAP2 and the control group. The MAP1 and MAP2 methods preserved the color of the samples and reduced the microbial growth rate. A lower formation of free fatty acids was observed in the samples packed with MAP1 and MAP2 than in the control group. The results showed that hydrogen gas positively affected the quality and storage time of samples.

Scent emitted from anal sac secretions provides important signals for most Carnivora. Their secretions emit a variety of volatile compounds, some of which function as chemical signals with information about the scent owners. The domestic cat has a pair of anal sac glands to secrete a pungent liquid. Their anal sac secretions may give information about sex, reproductive state, and recognition of individuals. However, little is known about the volatile compounds emitted from anal sac secretions and their biological functions in cats. In this study, we examined the volatile chemical profiles of anal sac secretions in cats and their olfactory ability to discriminate intraspecific anal sac secretions. Analysis with gas chromatography-mass spectrometry showed that the major volatile compounds were short-chain free fatty acids, whose contents varied among individuals, as well as other carnivores. There was no sex difference in the volatile profiles. In temporal analyses of individual anal sac secretions performed 2 months apart, the profiles were highly conserved within individuals. Habituation-dishabituation tests showed that cats can distinguish individual differences in the odor of anal sac secretions. These results suggest that cats utilize short-chain free fatty acids emitted from anal sac secretions to obtain scent information for individual recognition rather than species or sex recognition.

Novel polymeric nanoparticles (NPs) with uniform sizes were prepared from peptide-vinyl polymer diblock hybrids by the self-organized precipitation method. Hybrid polymers of polystyrene (PSt) and tetrapeptide (cell-binding epitope RGDS, reverse SDGR, cationic KKKK, and anionic DDDD) were successfully synthesized by combining solid-phase peptide synthesis and reversible addition fragmentation chain transfer polymerization methods. Narrowly dispersed hybrid polymers (polydispersity index < 1.25, M n 14 000-17 000) were obtained. Altering the preparation conditions easily tuned the size and size distribution of the NPs. When the ζ-potentials for the NP suspensions were measured at pH 6.0, the obtained values corresponded to the net charge of each peptide segment. More importantly, the NPs could encapsulate fluorescent Nile red (NR) and magnetic iron oxide NP (MNP), which might be suitable for fluorescent imaging and magnet-induced patterning of cells, respectively. The interactions of NPs with cells (NIH/3T3 fibroblast) and the magnetic effects were examined for NR/MNP-loaded PSt-RGDS and -SDGR NPs. Both NPs were readily incorporated into cells, but only NR/MNP-loaded PSt-RGDS NP showed magnetic responsiveness in cell adhesion and cultures.

Recently, bioinspired material such as nanoparticle has been successfully applied in the cancer therapy. However, how to precisely control the drug release from nanomedicine in tumor tissue and overcome the hypoxic microenvironment of tumor tissue is still an important challenge in the development of nanomedicine. In this work, a new type of drug-loaded nanoparticles P(AAm-co-AN)-AuNRs@CeO2-DOX (PA-DOX) was prepared by combining high-efficiency photothermal reagents, critical up-conversion temperature polymer layer and anti-cancer drug doxorubicin (DOX) for the treatment of hepatocellular carcinoma (HCC). In this system, CeO2 can decompose hydrogen peroxide to H2O and O2 alleviate the anaerobic microenvironment of liver cancer cells. As a photothermal reagent, AuNRs@CeO2 can convert near-infrared light into heat energy to achieve local heat to kill cancer cells and ablate solid tumors. In addition, the elevated temperature would enable the polymer layer to undergo a phase transition to release more DOX to achieve a controlled release mechanism, which will open up a new horizon for clinical cancer treatment.

Ionization of volatile organic compounds (VOCs) by coinage metal ions (Cu+, Ag+, and Au+) generated by laser desorption and ionization (LDI) of a metal nanolayer in subatmospheric conditions is explored. The study was performed in a commercial subatmospheric dual MALDI/ESI ion source. Five compounds representing different VOC classes were chosen for a detailed study of the metal ionization mechanism: ethanol, acetone, acetic acid, xylene, and cyclohexane. In the gas phase, ion molecular complexes of all three metal ions were formed, typically with two ligand molecules. The successful detection of the metal complexes with VOCs strongly depended on the applied voltages across the ion source, minimizing the in-source fragmentation. The employed orbital trap with ultrahigh resolving power and sub-parts-per-million mass accuracy allowed unambiguous identification of the formed complexes based on their molecular formulas. The detection limits of the studied compounds in the gas were in the range 0.1-1.4 nmol/L. Compared to Cu+ and Ag+ ions, Au+ ions exhibited the highest reactivity, often complicating spectra by side products of reactions. On the other hand, they also allowed detecting saturated hydrocarbons, which did not produce any signals with Ag+ and Cu+.

In this work, we present the synthesis and evaluation of magnetic resonance (MR) properties of novel phosphorus/iron-containing probes for dual 31P and 1H MR imaging and spectroscopy (MRI and MRS). The presented probes are composed of biocompatible semitelechelic and multivalent phospho-polymers based on poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC) coordinated with small paramagnetic Fe3+ ions or superparamagnetic maghemite (γ-Fe2O3) nanoparticles via deferoxamine group linked to the end or along the polymer chains. All probes provided very short 1H T1 and T2 relaxation times even at low iron concentrations. The presence of iron had a significant impact on the shortening of 31P relaxation, with the effect being more pronounced for probes based on γ-Fe2O3 and multivalent polymer. While the water-soluble probe having one Fe3+ ion per polymer chain was satisfactorily visualized by both 31P-MRS and 31P-MRI, the probe with multiple Fe3+ ions could only be detected by 31P-MRS, and the probes consisting of γ-Fe2O3 nanoparticles could not be imaged by either technique due to their ultra-short 31P relaxations. In this proof-of-principle study performed on phantoms at a clinically relevant magnetic fields, we demonstrated how the different forms and concentrations of iron affect both the 1H MR signal of the surrounding water molecules and the 31P MR signal of the phospho-polymer probe. Thus, this double contrast can be exploited to simultaneously visualize body anatomy and monitor probe biodistribution.

Randomness is perceived in two different extremes, in macroscopic homogeneity and local heterogeneity, but apparently far away from order. Here we show that a periodic order spontaneously arises from a binary random copolymer when self-assembly occurs in an ensemble containing > 1015 possible chain sequences. A Bernoullian distribution of hydrophilic and hydrophobic side chains grafted onto a linear backbone was constructed by random copolymerization. When the polymer chains associate in water, a sequence matching problem occurs because of the drastic heterogeneity in sequence: this is believed to generate local curvature mismatches which deviate from the ensemble-averaged interfacial curvature. Periodic folding of the self-assembled bilayer stabilizes the curvature instability as recurring hinges. Reminiscent of chain-folded lamellae found in polymer crystallization, this new liquid crystalline mesophase, characterized as bilayer-folded lamellae, manifests itself as an anisotropically alignable birefringent hydrogel with structural hierarchy across multiple length scales.

Chemical oscillatory reactions have attracted intensive attention due to their autonomous, continuous, and periodic features. Herein, the radicals generated in Belousov-Zhabotinsky (BZ) oscillator was used to initiate RAFT (reversible addition-fragmentation chain transfer) polymerization of 2-methoxyethyl acrylate (MEA) extending from hydrophilic poly(ethylene glycol) chain transfer agent (PEG-CTA) to give amphiphilic block copolymer, which self-assembled into collective objects with a size ranging from sub-micron to micron. Small-to-giant polymer vesicles could be generated using the above-mentioned BZ-PISA technology, the encapsulation of active BZ recipe into the vesicles also endorses the vesicles with growing features with potential for drug delivery and biomedical applications.

Superparamagnetic iron oxide nanoparticles (SPION) with a "non-fouling" surface represent a versatile group of biocompatible nanomaterials valuable for medical diagnostics, including oncology. In our study we present a synthesis of novel maghemite (γ-Fe2O3) nanoparticles with positive and negative overall surface charge and their coating by copolymer P(HPMA-co-HAO) prepared by RAFT (reversible addition-fragmentation chain-transfer) copolymerization of N-(2-hydroxypropyl)methacrylamide (HPMA) with N-[2-(hydroxyamino)-2-oxo-ethyl]-2-methyl-prop-2-enamide (HAO). Coating was realized via hydroxamic acid groups of the HAO comonomer units with a strong affinity to maghemite. Dynamic light scattering (DLS) demonstrated high colloidal stability of the coated particles in a wide pH range, high ionic strength, and the presence of phosphate buffer (PBS) and serum albumin (BSE). Transmission electron microscopy (TEM) images show a narrow size distribution and spheroid shape. Alternative coatings were prepared by copolymerization of HPMA with methyl 2-(2-methylprop-2-enoylamino)acetate (MMA) and further post-polymerization modification with hydroxamic acid groups, carboxylic acid and primary-amino functionalities. Nevertheless, their colloidal stability was worse in comparison with P(HPMA-co-HAO). Additionally, P(HPMA-co-HAO)-coated nanoparticles were subjected to a bio-distribution study in mice. They were cleared from the blood stream by the liver relatively slowly, and their half-life in the liver depended on their charge; nevertheless, both cationic and anionic particles revealed a much shorter metabolic clearance rate than that of commercially available ferucarbotran.

Sensory assessment of virgin olive oil ("panel test") is the only sensory method included in international regulations of edible oils and its application is compulsory. Even if its application has been a success in quality control, improving the quality of virgin olive oils over the last 30 years, at present, there is no reference material (RM), in the strict sense of the term, to be used as a validated standard for sensory defects of virgin olive oil with which tasters can be trained. Usually, real samples of virgin olive oils assessed by many panels for the International Olive Council (IOC) ring tests are used as materials of reference in panel training and control. The latter are highly representative of the main perceived defects, but availability is limited, samples are not homogeneous year after year, and other secondary defects can be present. Thus, in order to provide solutions, this work describes an analytical procedure for implementing olfactory formulations that emulate rancid and winey-vinegary defects found in virgin olive oils with the aim of providing reproducible RMs that can be prepared on demand. A strategy for designing RMs for aroma is presented and the optimization process to obtain the best formulation is described. Under the criteria of representativeness, verified with the advice of the IOC, aroma persistence, and simplicity in formulation, two RMs for winey-vinegary and rancid were obtained by diluting acetic acid and ethanol (winey-vinegary defect) and hexanal (rancid defect) together with other compounds that are used to modify aroma and avoid non-natural sensory notes.

We report new dual acidic pH/reduction-responsive degradable amphiphilic block copolymers featured with dual acidic pH-labile acetal linkage and a reductively-cleavable disulfide bond at the hydrophilic/hydrophobic block junction as well as pendant disulfide bonds in the hydrophobic block. Centered on the use of a macroinitiator approach, three strategies utilize the combination of atom transfer radical polymerization and reversible addition fragmentation chain transfer polymerization in a sequential or concurrent mechanism, along with facile coupling reactions. Combined structural analysis with dual-stimuli-responsive degradation investigation allows better understanding of the architectures and orthogonalities of the formed block copolymers as a diblock or a triblock copolymer. Our study presents the development of effective synthetic strategies to well-defined multifunctional amphiphilic block copolymers that exhibit dual-stimuli-responsive degradation at dual location (called the DL-DSRD strategy), thus potentially promising as nanoassemblies for effective drug delivery.

Biomolecular condensates are emerging as an efficient strategy developed by cells to control biochemical reactions in space and time by locally modifying composition and environment. Yet, local increase in protein concentration within these compartments could promote aberrant aggregation events, including the nucleation and growth of amyloid fibrils. Understanding protein stability within the crowded and heterogeneous environment of biological condensates is therefore crucial, not only when the aggregation-prone protein is the scaffold element of the condensates but also when proteins are recruited as client molecules within the compartments. Here, we investigate the partitioning and aggregation kinetics of the amyloidogenic peptide Abeta42 (Aβ-42), the peptide strongly associated with Alzheimer's disease, recruited into condensates based on low complexity domains (LCDs) derived from the DEAD-box proteins Laf1, Dbp1 and Ddx4, which are associated with biological membraneless organelles. We show that interactions between Aβ-42 and the scaffold proteins promote sequestration and local increase of the peptide concentration within the condensates. Yet, heterotypic interactions within the condensates inhibit the formation of amyloid fibrils. These results demonstrate that biomolecular condensates could sequester aggregation-prone proteins and prevent aberrant aggregation events, despite the local increase in their concentration. Biomolecular condensates could therefore work not only as hot-spots of protein aggregation but also as protective reservoirs, since the heterogenous composition of the condensates could prevent the formation of ordered fibrillar aggregates.

In this work, dihydro-5-hydroxyl furan-2-one (2H-HBO), a renewable-sourced chemical containing the hydroxyl functionality, is converted into its acrylic counterpart for the first time through a green chemical procedure using methacrylic anhydride. This newly synthesized acrylic monomer is able to be polymerized using different techniques such as bulk, solution, and emulsion polymerization. The ability of this monomer to copolymerize with other commercially available acrylates is studied using emulsion polymerization techniques. The pendent lactone ring remains unopened during polymerization and the new monomer is able to copolymerize with other acrylates such as methyl methacrylate and styrene. Reversible addition-fragmentation chain transfer reaction emulsion polymerization is also studied with the same monomer, leading to a steady conversion (∼60%) with a low polydispersity of 1.06. The homopolymer produced from such an emulsion polymerization shows a higher molecular weight than that produced from other methods, with a glass transition temperature of around 105 °C. This demonstrates the potential of this monomer as an interesting, green replacement for methyl methacrylate in certain fields of application.

In the chemical investigation of marine unicellular bacteria, a new peptide, thalassospiramide G (1), along with thalassospiramides A and D (2-3), was discovered from a large culture of Thalassospira sp. The structure of thalassospiramide G, bearing γ-amino acids, such as 4-amino-5-hydroxy-penta-2-enoic acid (AHPEA), 4-amino-3,5-dihydroxy-pentanoic acid (ADPA), and unique 2-amino-1-(1H-indol-3-yl) ethanone (AIEN), was determined via extensive spectroscopic analysis. The absolute configuration of thalassospiramide D (3), including 4-amino-3-hydroxy-5-phenylpentanoic acid (AHPPA), was rigorously determined by 1H-1H coupling constant analysis and chemical derivatization. Thalassospiramides A and D (2-3) inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated mouse macrophage RAW 264.7 cells, with IC(50) values of 16.4 and 4.8 μM, respectively.

The controlled folding of synthetic polymer chains into single-chain polymeric nanoparticles (SCPNs) of defined size and shape in water is a viable way to create compartmentalized, nanometer-sized structures for a range of biological applications. Understanding the relationship between the polymer's microstructure and the stability of folded structures is crucial to achieving desired applications. Here, we introduce the solvatochromic dye Nile red into SCPNs and apply a combination of spectroscopic and microscopic techniques to relate polymer microstructure to nanoparticle stability in complex biological media and cellular environments. Our experimental data show that the polymer's microstructure has little effect on the stability of SCPNs in biological media and cytoplasm of living cells, but only SCPNs comprising supramolecular benzene-1,3,5-tricarboxamide (BTA) motifs showed good stability in lysosomes. The results indicate that the polymer's microstructure is vital to ensure nanoparticle stability in highly competitive environments: both hydrophobic collapse and a structured interior are required. Our study provides an accessible way of probing the stability of SCPNs in cellular environments and paves the way for designing highly stable SCPNs for efficient bio-orthogonal catalysis and sensing applications.

Metal Organic Frameworks (MOFs) present high surface areas, various pore topology as well as good stabilities. The functionalities and porosity can be tuned by using different linkers with various functional groups and a wide range of linker lengths. These properties make them good candidates in membrane separation applications. In this work, we propose a simple UiO-66 MOF-based membrane fabrication method following two steps. First, the α-alumina tubular membrane support was dip-coated with MOF-polymer hybrid nanoparticles (NPs). These NPs were prepared via one-pot synthesis by adding poly (methacrylic acid)-b-poly (methyl methacrylate) (PMAA-b-PMMA) NPs to the classical acetic acid-modulated UiO-66 or UiO-66-NH2 synthesis formulation. Second, secondary membrane growth was applied to give rise to a continuous and homogeneous crystalline MOF membrane layer. The gas permeances (He, N2, CO2 and SF6) tests confirmed high membrane permeability with no macro-defects. The as-prepared membranes that were used for dye separation (Rhodamine B) showed relatively good separation capacity.