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Molecular Medicine Reports Aug 2024Chronic low‑grade inflammation defines obesity as a metabolic disorder. Alterations in the structure of gut flora are strongly associated with obesity. Lactoferrin...
Chronic low‑grade inflammation defines obesity as a metabolic disorder. Alterations in the structure of gut flora are strongly associated with obesity. Lactoferrin (LF) has a biological function in regulating intestinal flora. The present study aimed to investigate the therapeutic and anti‑-inflammatory effects of LF in obese mice based on intestinal flora. A total of 30 C57BL/6 mice were divided into three groups consisting of 10 mice each. Subsequently, one group was fed a normal diet (Group K), another group was fed a high‑fat diet (Group M) and the remaining group switched from regular drinking to drinking 2% LF water (Group Z2) after 2 weeks of high‑fat diet; all mice were fed for 12 weeks. After the experiment, the mouse blood lipid and lipopolysaccharide levels, levels of inflammatory factors and intestinal tight junction proteins were assessed. Mouse stool samples were analyzed using 16S ribosomal RNA sequencing. The results showed that LF reduced serum total cholesterol, triglycerides and low‑density lipoprotein levels, elevated high‑density lipoprotein levels, suppressed metabolic endotoxemia and attenuated chronic low‑grade inflammatory responses in obese mice. In addition, LF upregulated zonula occludens‑1 and occludin protein expression levels in the intestine, thereby improving intestinal barrier integrity. LF altered the intestinal microbial structure of obese mice, reduced the ratio of and an elevated ratio of , modifying the bacterial population to the increased relative abundance of and .
Topics: Animals; Lactoferrin; Gastrointestinal Microbiome; Mice; Obesity; Male; Inflammation; Mice, Inbred C57BL; Diet, High-Fat; Mice, Obese; Occludin; Lipopolysaccharides
PubMed: 38873986
DOI: 10.3892/mmr.2024.13262 -
Dalton Transactions (Cambridge, England... Jun 2024Physiological or pathophysiological changes lead to posttranslational changes in the sialic acid content of human serum transferrin (hTf), an essential mediator of iron...
Physiological or pathophysiological changes lead to posttranslational changes in the sialic acid content of human serum transferrin (hTf), an essential mediator of iron transport in the human body, resulting in a significantly increased concentration of desialylated hTf. The intrinsic fluorescence quenching upon binding of iron to hTf was successfully modeled using the binding polynomial for two iron-binding sites, allowing measurements in a high-throughput format. Removal of sialic acid residues resulted in a 3-fold increase in iron binding affinity for both sites of hTf at pH 7.4. The pH-dependence of iron binding showed significant differences in equilibrium constants, resulting in a 10-fold increase in binding affinity for desialylated hTf at pH 5.9. The changes in hTf sialylation apparently result in tuning of the stability of the conformational state, which in turn contributes to the stability of the diferric hTf. The observed differences in the conditional thermodynamic equilibrium constants suggest that the desialylated protein has a higher preference for diferric hTf over monoferric hTf species down to pH 6.5, which may also influence the interaction with transferrin receptors that preferentially bind to diferric hTf. The results suggest a link between changes in hTf glycan structure and alterations in iron binding equilibrium associated with tissue acidosis.
Topics: Transferrin; Humans; Hydrogen-Ion Concentration; Protein Binding; Iron; N-Acetylneuraminic Acid; Ferric Compounds; Binding Sites; Thermodynamics
PubMed: 38873789
DOI: 10.1039/d4dt01311e -
Science (New York, N.Y.) Jun 2024Respiratory complex I is an efficient driver for oxidative phosphorylation in mammalian mitochondria, but its uncontrolled catalysis under challenging conditions leads...
Respiratory complex I is an efficient driver for oxidative phosphorylation in mammalian mitochondria, but its uncontrolled catalysis under challenging conditions leads to oxidative stress and cellular damage. Ischemic conditions switch complex I from rapid, reversible catalysis into a dormant state that protects upon reoxygenation, but the molecular basis for the switch is unknown. We combined precise biochemical definition of complex I catalysis with high-resolution cryo-electron microscopy structures in the phospholipid bilayer of coupled vesicles to reveal the mechanism of the transition into the dormant state, modulated by membrane interactions. By implementing a versatile membrane system to unite structure and function, attributing catalytic and regulatory properties to specific structural states, we define how a conformational switch in complex I controls its physiological roles.
Topics: Animals; Cryoelectron Microscopy; Electron Transport Complex I; Ischemia; Lipid Bilayers; Mitochondria; Oxidative Phosphorylation; Cattle; Ubiquinone; Protein Conformation, alpha-Helical
PubMed: 38870289
DOI: 10.1126/science.ado2075 -
Physical Chemistry Chemical Physics :... Jun 2024Transition metal ions play crucial roles in the structure and function of numerous proteins, contributing to essential biological processes such as catalysis, electron... (Review)
Review
Transition metal ions play crucial roles in the structure and function of numerous proteins, contributing to essential biological processes such as catalysis, electron transfer, and oxygen binding. However, accurately modeling the electronic structure and properties of metalloproteins poses significant challenges due to the complex nature of their electronic configurations and strong correlation effects. Multiconfigurational quantum chemistry methods are, in principle, the most appropriate tools for addressing these challenges, offering the capability to capture the inherent multi-reference character and strong electron correlation present in bio-inorganic systems. Yet their computational cost has long hindered wider adoption, making methods such as density functional theory (DFT) the method of choice. However, advancements over the past decade have substantially alleviated this limitation, rendering multiconfigurational quantum chemistry methods more accessible and applicable to a wider range of bio-inorganic systems. In this perspective, we discuss some of these developments and how they have already been used to answer some of the most important questions in bio-inorganic chemistry. We also comment on ongoing developments in the field and how the future of the field may evolve.
Topics: Metalloproteins; Density Functional Theory; Transition Elements; Chemistry, Bioinorganic; Quantum Theory
PubMed: 38868993
DOI: 10.1039/d4cp01297f -
Journal of Agricultural and Food... Jun 2024Thymol has efficient bactericidal activity against a variety of pathogenic bacteria, but the bactericidal mechanism against () has rarely been reported. In the current...
Thymol has efficient bactericidal activity against a variety of pathogenic bacteria, but the bactericidal mechanism against () has rarely been reported. In the current study, we investigated the bactericidal mechanism of thymol against . The Results revealed that 150 μg/mL of thymol had 99.9% bactericidal activity on . Intracellular bursts of reactive oxygen species (ROS), Feaccumulation, lipid peroxidation, and DNA breakage were checked by cell staining. The exogenous addition of HO and catalase promoted and alleviated thymol-induced cell death to a certain extent, respectively, and the addition of the ferroptosis inhibitor Liproxstatin-1 also alleviated thymol-induced cell death, confirming that thymol induced Fenton-reaction-dependent ferroptosis in . Proteomic analysis revealed that relevant proteins involved in ROS production, lipid peroxidation accumulation, and DNA repair were significantly upregulated after thymol treatment. Molecular docking revealed two potential binding sites (amino acids 46H and 42F) between thymol and ferritin, and thymol could promote the release of Fe from ferritin proteins through in vitro interactions analyzed. Therefore, we hypothesized that ferritin as a potential target may mediate thymol-induced ferroptosis in . This study provides new ideas for the development of natural inhibitors for controlling in aquatic products.
Topics: Ferroptosis; Thymol; Reactive Oxygen Species; Vibrio parahaemolyticus; Hydrogen Peroxide; Anti-Bacterial Agents; Lipid Peroxidation; Iron; Molecular Docking Simulation; Ferritins; Bacterial Proteins
PubMed: 38867141
DOI: 10.1021/acs.jafc.4c01584 -
Cell Jun 2024Microbial hydrogen (H) cycling underpins the diversity and functionality of diverse anoxic ecosystems. Among the three evolutionarily distinct hydrogenase superfamilies...
Microbial hydrogen (H) cycling underpins the diversity and functionality of diverse anoxic ecosystems. Among the three evolutionarily distinct hydrogenase superfamilies responsible, [FeFe] hydrogenases were thought to be restricted to bacteria and eukaryotes. Here, we show that anaerobic archaea encode diverse, active, and ancient lineages of [FeFe] hydrogenases through combining analysis of existing and new genomes with extensive biochemical experiments. [FeFe] hydrogenases are encoded by genomes of nine archaeal phyla and expressed by H-producing Asgard archaeon cultures. We report an ultraminimal hydrogenase in DPANN archaea that binds the catalytic H-cluster and produces H. Moreover, we identify and characterize remarkable hybrid complexes formed through the fusion of [FeFe] and [NiFe] hydrogenases in ten other archaeal orders. Phylogenetic analysis and structural modeling suggest a deep evolutionary history of hybrid hydrogenases. These findings reveal new metabolic adaptations of archaea, streamlined H catalysts for biotechnological development, and a surprisingly intertwined evolutionary history between the two major H-metabolizing enzymes.
Topics: Hydrogenase; Phylogeny; Hydrogen; Archaea; Models, Molecular; Iron-Sulfur Proteins; Genome, Archaeal; Archaeal Proteins
PubMed: 38866018
DOI: 10.1016/j.cell.2024.05.032 -
Redox Biology Aug 2024Hydrogen sulfide (HS) has recently been recognized as an important gaseous transmitter with multiple physiological effects in various species. Previous studies have...
Hydrogen sulfide (HS) has recently been recognized as an important gaseous transmitter with multiple physiological effects in various species. Previous studies have shown that HS alleviated heat-induced ganoderic acids (GAs) biosynthesis, an important quality index of Ganoderma lucidum. However, a comprehensive understanding of the physiological effects and molecular mechanisms of HS in G. lucidum remains unexplored. In this study, we found that heat treatment reduced the mitochondrial membrane potential (MMP) and mitochondrial DNA copy number (mtDNAcn) in G. lucidum. Increasing the intracellular HS concentration through pharmacological and genetic means increased the MMP level, mtDNAcn, oxygen consumption rate level and ATP content under heat treatment, suggesting a role for HS in mitigating heat-caused mitochondrial damage in G. lucidum. Further results indicated that HS activates sulfide-quinone oxidoreductase (SQR) and complex III (Com III), thereby maintaining mitochondrial homeostasis under heat stress in G. lucidum. Moreover, SQR also mediated the negative regulation of HS to GAs biosynthesis under heat stress. Furthermore, SQR might be persulfidated under heat stress in G. lucidum. Thus, our study reveals a novel physiological function and molecular mechanism of HS signalling under heat stress in G. lucidum with broad implications for research on the environmental response of microorganisms.
Topics: Hydrogen Sulfide; Reishi; Triterpenes; Mitochondria; Homeostasis; Heat-Shock Response; Membrane Potential, Mitochondrial; Quinone Reductases; DNA, Mitochondrial; Electron Transport Complex III
PubMed: 38865903
DOI: 10.1016/j.redox.2024.103227 -
Journal of Agricultural and Food... Jun 2024In this work, lactoferrin (LF)-chitosan (CS) composite hydrogels with good loading capacity of thermosensitive bioactive substances were successfully obtained by...
In this work, lactoferrin (LF)-chitosan (CS) composite hydrogels with good loading capacity of thermosensitive bioactive substances were successfully obtained by microbial transglutaminase (MTG)-induced cross-linking. We evaluated the rheological, textural, and microstructural characteristics of the composite hydrogels under different conditions. The results demonstrated that the concentrations of LF and CS as well as the amount of MTG could regulate the textural properties, rheological properties, and water holding capability. The results of FTIR and fluorescence spectroscopy indicated that the main interactions within the composite gel were hydrogen and isopeptide bonds. Additionally, in vitro digestion simulation results verified that riboflavin kept stable in stomach due to the protection of LF-CS composite hydrogels and was released in small intestine. These results suggested that thermosensitive bioactive substance could be encapsulated and delivered by the LF-CS composite hydrogel, which could be applied in lots of potential applications in functional food as a new material.
Topics: Transglutaminases; Hydrogels; Chitosan; Lactoferrin; Rheology; Bacterial Proteins; Drug Delivery Systems; Drug Carriers; Digestion
PubMed: 38865607
DOI: 10.1021/acs.jafc.4c01551 -
Science Advances Jun 2024Nitrogenase plays a key role in the global nitrogen cycle; yet, the evolutionary history of nitrogenase and, particularly, the sequence of appearance between the...
Nitrogenase plays a key role in the global nitrogen cycle; yet, the evolutionary history of nitrogenase and, particularly, the sequence of appearance between the homologous, yet distinct NifDK (the catalytic component) and NifEN (the cofactor maturase) of the extant molybdenum nitrogenase, remains elusive. Here, we report the ability of NifEN to reduce N at its surface-exposed L-cluster ([FeSC]), a structural/functional homolog of the M-cluster (or cofactor; [(-homocitrate)MoFeSC]) of NifDK. Furthermore, we demonstrate the ability of the L-cluster-bound NifDK to mimic its NifEN counterpart and enable N reduction. These observations, coupled with phylogenetic, ecological, and mechanistic considerations, lead to the proposal of a NifEN-like, L-cluster-carrying protein as an ancient nitrogenase, the exploration of which could shed crucial light on the evolutionary origin of nitrogenase and related enzymes.
Topics: Nitrogenase; Phylogeny; Nitrogen; Molybdoferredoxin; Models, Molecular; Bacterial Proteins; Nitrogen Fixation
PubMed: 38865457
DOI: 10.1126/sciadv.ado6169 -
Nan Fang Yi Ke Da Xue Xue Bao = Journal... May 2024To investigate the mechanisms that mediate the neuroprotective effect of the intestinal microbial metabolite sodium butyrate (NaB) in a mouse model of Parkinson's...
OBJECTIVE
To investigate the mechanisms that mediate the neuroprotective effect of the intestinal microbial metabolite sodium butyrate (NaB) in a mouse model of Parkinson's disease (PD) the gut-brain axis.
METHODS
Thirty-nine 7-week-old male C57BL/6J mice were randomized equally into control group, PD model group, and NaB treatment group. In the latter two groups, PD models were established by intraperitoneal injection of 30 mg/kg 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) once daily for 5 consecutive days, and normal saline was injected in the control group. After modeling, the mice received daily gavage of NaB (300 mg/kg) or an equal volume of saline for 14 days. Behavioral tests were carried out to assess the changes in motor function of the mice, and Western blotting was performed to detect the expressions of tyrosine hydroxylase (TH) and -synuclein (-syn) in the striatum and nuclear factor-κB (NF-κB), tumor necrosis factor (TNF-), interleukin 6 (IL-6), and the tight junction proteins ZO-1, Occludin, and Claudinin the colon. HE staining was used to observe inflammatory cell infiltration in the colon of the mice. RNA sequencing analysis was performed to identify the differentially expressed genes in mouse colon tissues, and their expressions were verified using qRT-PCR and Western blotting.
RESULTS
The mouse models of PD with NaB treatment showed significantly increased movement speed and pulling strength of the limbs with obviously upregulated expressions of TH, Occludin, and Claudin and downregulated expressions of -syn, NF-κB, TNF-, and IL-6 (all < 0.05). HE staining showed that NaB treatment significantly ameliorated inflammatory cell infiltration in the colon of the PD mice. RNA sequencing suggested that Bmal1 gene probably mediated the neuroprotective effect of NaB in PD mice ( < 0.05).
CONCLUSION
NaB can improve motor dysfunction, reduce dopaminergic neuron loss in the striatum, and ameliorate colonic inflammation in PD mice possibly through a mechanism involving Bmal1.
Topics: Animals; Mice; Butyric Acid; Male; Mice, Inbred C57BL; Neuroprotective Agents; Disease Models, Animal; Parkinson Disease; alpha-Synuclein; Tumor Necrosis Factor-alpha; NF-kappa B; Interleukin-6; Tyrosine 3-Monooxygenase; 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Corpus Striatum; Occludin; Brain-Gut Axis
PubMed: 38862445
DOI: 10.12122/j.issn.1673-4254.2024.05.09