Metabolic Activity Research Articles

Exploring the Diversity of Some Microorganisms from Lake Al-Asfar, KSA: The Good, the Bad, and the Pathogenic

Background: Lake Al-Asfar in KSA was used as a sink for wastewater for decades and suffered from pollution. The lake is a habitat to different microbial species that play important ecological roles, some of which are good, and some are bad and even pathogenic. In a previous investigation, algal-bacteria consortia have proven to be beneficial in bioremediating heavy metals and hydrocarbons in Lake Al-Asfar. The identity of algae was revealed to be Chlorella sp. and Geitlernema sp. in the consortia. The identity of the heterotrophic bacterial partners, on the other hand, awaits investigation and is addressed in the present research. On the other hand, investigating the diversity of Protozoa and parasites is also tackled as they represent indicators of pollution. Some pose serious health risks, but some of them also contribute to reducing some of the pollution levels. Methods: Bacteria associated with algae were isolated in pure form. The polyphasic approach was used to identify bacterial samples, including staining procedures, the use of Vitek technology, and scanning electron microscopy. This information was integrated with structure information such as capsule presence, endospore formation, and wall characteristics indicated by Gram stain. With regard to protists including Protozoa and parasites, Light microscopy and taxonomic books of identification were used to reveal their identity. Results: three main bacterial strains belonging to the following genera were identified: Sphingomonas, Rhizobium, and Enterbacter. The last is potentially pathogenic and poses health risks to Lake goers. Rhizobium, on the other hand, is most likely found in the lake from agricultural wastewater and is a nitrogen fixer that increases the fertility of crops. The first bacterium is associated with special lipid metabolism and is hardly pathogenic. Several diverse microscopic forms of protists, mainly Protozoa and parasites, were identified, which included Entamoeba histolytica, Balantidium coli, Ascaris lumbricoides, Amoeba, Paramecium, Euglena, and Gymnodinium sp. Discussion: The three types of bacteria identified have metabolic activities that are associated with bioremediation. On the other hand, protists, including Protozoa and parasites, are regular members of wastewater communities and help in scavenging solid wastes, but they cause hazards such as secreting toxins, causing disease, and impacting the bioremediation potential by feeding on beneficial bioremediating algae and bacteria. This is part of the wastewater ecosystem dynamics, but efforts must be exerted to minimize, if not completely eliminate, pathogenic parasites in order to maximize the growth of algal consortia. Conclusions: Vitek technology is an emerging less time- and effort-consuming fast technology for identifying bacteria. Bacteria identified have significant ecological bioremediating roles, together with their algal partners, but some pose pathogenic risks. Identifying co-inhabitants like protists and parasites helps to shed light on their impact on one another and pave the way for restoration efforts that minimize the biological hazards and maximize the use of beneficial local microorganisms.

Tuning Surface Chemistry Impacts on Cardiac Endothelial and Smooth Muscle Cell Development.

Cardiovascular diseases (CVDs) are the leading causes of death worldwide, with approx. Twenty million deaths in 2021. Cardiovascular implants are among the most used biomaterials in the clinical world. However, poor endothelialisation and rapid thrombosis remains a challenge. Simple chemical surface modification techniques can be used to steer biological interactions without affecting the bioimplants' overall bulk characteristics such as radiopacity and flexibility. Although silanes are well studied for protein and cell interactions, the methodical investigation of cardiac endothelial cell (EC) alongside smooth muscle cell (SMC) to mimic natural arterial environments has been limited. In this study, these cells have been investigated on surfaces functionalized with methyl, amine, thiol, methacrylate, and fluorine organosilane groups. Cardiac EC and SMC growth was investigated with metabolic activity, time lapse imaging, and immunofluorescent staining techniques. The results demonstrated that the surfaces tested are able to selectively regulate the viability and growth of the cells. Aminosilane modified surfaces displayed 2-fold higher metabolic activity with HUVEC and 2-fold less metabolic activity with HCASMC cell lines, compared to tissue culture plastic controls. The amino-modification outperformed all other chemistries tested in terms of ability to promote the proliferation of ECs, while importantly reducing the activity of SMCs. This report demonstrates that aminosilane modified surfaces have the potential to be utilized in novel cardiovascular implants, which could improve biological integration in the short and possibly longer-term. The findings of this study suggest that specific chemical modifications of the surface can enhance endothelial cell activity while minimizing the proliferation of smooth muscle cells, which are often associated with thrombosis. This highlights the potential of carefully engineered surface chemistries to improve the clinical outcomes of cardiovascular implants.

The role of acetylation and deacetylation in cancer metabolism.

As a hallmark of cancer, metabolic reprogramming adjusts macromolecular synthesis, energy metabolism and redox homeostasis processes to adapt to and promote the complex biological processes of abnormal growth and proliferation. The complexity of metabolic reprogramming lies in its precise regulation by multiple levels and factors, including the interplay of multiple signalling pathways, precise regulation of transcription factors and dynamic adjustments in metabolic enzyme activity. In this complex regulatory network, acetylation and deacetylation, which are important post-translational modifications, regulate key molecules and processes related to metabolic reprogramming by affecting protein function and stability. Dysregulation of acetylation and deacetylation may alter cancer cell metabolic patterns by affecting signalling pathways, transcription factors and metabolic enzyme activity related to metabolic reprogramming, increasing the susceptibility to rapid proliferation and survival. In this review, we focus on discussing how acetylation and deacetylation regulate cancer metabolism, thereby highlighting the central role of these post-translational modifications in metabolic reprogramming, and hoping to provide strong support for the development of novel cancer treatment strategies. KEY POINTS: Protein acetylation and deacetylation are key regulators of metabolic reprogramming in tumour cells. These modifications influence signalling pathways critical for tumour metabolism. They modulate the activity of transcription factors that drive gene expression changes. Metabolic enzymes are also affected, altering cellular metabolism to support tumour growth.

Meso-Substituted AB3-type phenothiazinyl porphyrins and their indium and zinc complexes photosensitising properties, cytotoxicity and phototoxicity on ovarian cancer cells.

New meso-substituted AB3-type phenothiazinyl porphyrins and ferrocenylvinyl phenothiazinyl porphyrin were synthesised by Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions, respectively. The free porphyrins were further used in the synthesis of new indium(iii) or zinc(ii) porphyrin complexes. All porphyrins exhibit red fluorescence emission in solution, a property that remains unimpaired following internalisation in ovarian A2780 cancer cells, as evidenced by fluorescence microscopy images. The In(iii) phenothiazinyl porphyrin complexes show a higher quantum yield of fluorescence emission (2aΦ F = 30%, 4aΦ F = 29%, 5aΦ F = 28%) compared to the free base porphyrin precursors, or Zn(ii) complex 4b (Φ F = 10%). The potential of novel phenothiazinyl porphyrins to act as photosensitisers was evaluated using two distinct approaches. The first was through the measurement of the singlet oxygen quantum yield Φ Δ(1O2), while the second employed in vitro measurements of metabolic activity, oxidative stress, nuclear factor-erythroid 2 related factor 2 (Nrf-2) activation and tumour necrosis factor-alpha (TNF-α) under both dark and light irradiation conditions. As reflected by the IC50 values, the most potent cytotoxicity of the phenothiazinyl porphyrins against the A2780 cells was observed for In(iii) ferrocenylvinyl phenothiazinyl porphyrin 4a (36.38 μM), the remaining compounds are less cytotoxic. The reduction in metabolic activity was observed in A2780 ovarian tumour cells treated with 4a and 6a and exposed to light compared to treatment in the absence of light. The oxidative stress, TNF-α and Nrf-2 transcription factor were particularly notable when A2780 cells were treated with 4a and subsequently photoirradiated, the oxidative stress was linked to the highest value of Φ Δ(1O2) recorded for 4a (60%).

Assessing the effects of drought stress on photosynthetic performance and physiological resistance in camphor seedling leaves.

The impact of seasonal short-term drought on plant physiology and resilience is crucial for conservation and management strategies. This study investigated drought stress effects on growth, photosynthetic capacity, and physiological responses of Camphor (Cinnamomum camphora) seedlings in Guangxi province, China. Fertilized potted plants underwent continuous drought treatments to assess varying water supply effects. Treatments included normal water supply (CK), light drought (D1), moderate drought (D2), and severe drought (D3). Physiological indicators including net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and intercellular CO2 concentration (Ci) were measured. Additionally, the stomatal limitation value (Ls) was calculated using the formula Ls = 1-Ci/Ca, and water use efficiency (WUE) was computed as Pn/Tr. Furthermore, parameters such as PIABS (Performance Index based on absorbed light energy), WK (the ratio of variable fluorescence FK at the K point to the amplitude FO-FJ), VJ (the ratio of variable fluorescence FJ at the J point to the amplitude FO-FP), ΔI/I0 (the relative amplitude of the 820 nm light absorption curve), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) were measured to evaluate the impact of drought stress on various physiological processes and antioxidant enzyme activities. Results showed significant decreases in base diameter growth (GD) and seedling height growth (GH) with increasing drought stress. Notably, moderate (D2) and severe (D3) drought treatments led to negative GD values. GD decreased by 23.79%, 114.85%, and 175.50% for D1, D2, and D3 treatments, respectively, while reductions of 40.00%, 73.33%, and 90.00% in GD were observed compared to the control (CK). Pn decreased significantly across treatments, with D1<CK<D2<D3 in Ci. Stomatal limit value (Ls) and water use efficiency (WUE) followed the order: D1>CK>D2>D3. Light energy transmission to PSI by the unit reaction center (REo/RC) initially increased then decreased, significantly smaller in D3 compared to D1. Conversely, heat dissipation absorbed by the unit reaction center (DIo/RC) increased notably in D3 compared to D1 and CK. PIABS, WK, VJ, and ΔI/I0 decreased over time, while Rubisco enzyme activity decreased, while proline (Pro) levels increased. Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) levels significantly increased during D1 treatment but decreased with D2 and D3 treatments. Overall, drought severity had varying impacts on Cinnamomum camphora growth and photosynthetic structure, with D1 treatment maintaining normal growth and metabolic activities, while D2 and D3 treatments resulted in severe membrane damage, rendering seedlings essentially unable to survive. These findings provide a theoretical basis for implementing water management practices and conservation strategies for camphor seedlings.

Nanostructured lipid carriers as a strategy to enhance oral levosulpiride delivery: An in vitro and ex vivo assessment.

Oral absorption is limited for many small-molecule drugs due to their poor aqueous solubility as well as, for some, poor membrane permeation. One such is levosulpiride (LSP), used to treat psychotic and other conditions. The present study aims to explore the effect of nanostructured lipid carriers (NLCs) for the delivery of LSP. The permeation of LSP in vitro and ex vivo as well as effects on the epithelium and mucosa was monitored. In vitro and ex vivo permeation studies exhibited an 8-fold and 1.6-fold increase in the Papp of LSP respectively, as compared to unformulated LSP applied as a suspension. Transepithelial electrical resistance (TEER) measured in real-time by impedance spectroscopy decreased during exposure yet recovered upon removal of the NLCs. Together with the increased passage of the paracellular markers [14C]-mannitol and FD4 applied together with blank NLCs, but not the transcellular marker [3H]-metoprolol, this indicates permeation of LSP via the paracellular pathway. The reversible effect on integrity was associated with altered cell morphology confirmed by occludin and f-actin localization with insignificant effect on metabolic activity. These results suggest that the NLCs and/or components thereof can mediate improved absorption of drugs by increasing the permeability of the intestinal epithelial membrane, further facilitated by increased drug solubilization.

The impact of fermentation length and dough composition on the stability of liquid sourdough starters

Sourdough breadmaking on an industrial scale requires robust, well-performing starters that bring attractive characteristics to the product. The active nature of liquid starters provides a faster fermentation process compared to their dehydrated counterparts. However, liquid sourdough starters require meticulous management in order to maintain stability and functionality during cold storage at 4 °C.This study investigated the stability of three liquid sourdough starters during storage and also the impact of prolonged fermentation, the addition of diastatic malted wheat flour, and a neutralising agent (CaCO3).The sourdough starters were evaluated for their microbial viability and metabolic activity at three individual time points during 16 weeks of cold storage. The microbial composition was analysed using culture-dependent and culture-independent methods, and metabolic changes were investigated using chromatographic methods.Two types of sourdough starter showed satisfying viability of lactic acid bacteria (> 7 log CFU/g) and metabolic stability throughout 16 weeks of cold storage. The introduction of malted wheat flour and CaCO3 caused a decline in viability to <7 log CFU/g within 8 weeks in the third sourdough starter type and additionally revealed an ongoing metabolic activity of this sourdough starter during cold storage.Prolonged fermentation influenced the free amino acid profile, whereas adjusting the sourdough starter formula resulted in a different fungal microbiota and increased levels of fermentable substrates (maltose), organic acids (lactic acid), and aromatic compounds (alcohol and aldehydes).These findings provide stakeholders and researchers in sourdough fermentation technology with new insights concerning the stability of cold-stored liquid sourdough starters.

Rapid microfluidic perfusion system enables controlling dynamics of intracellular pH regulated by Na+/H+ exchanger NHE1.

pH regulation of eukaryotic cells is of crucial importance and influences different mechanisms including chemical kinetics, buffer effects, metabolic activity, membrane transport and cell shape parameters. In this study, we develop a microfluidic system to rapidly and precisely control a continuous flow of ionic chemical species to acutely challenge the intracellular pH regulation mechanisms and confront predictive models. We monitor the intracellular pH dynamics in real-time using pH-sensitive fluorescence imaging and establish a robust mathematical tool to translate the fluorescence signals to pH values. By varying flow rate across the cells and duration for the rinsing process, we manage to tweak the dynamics of intracellular pH from a smooth recovery to either an overshooting state, where the pH goes excitedly to a maximum value before decreasing to a plateau, or an undershooting state, where the pH is unable to recover to ∼7. We believe our findings will provide more insight into intracellular regulatory mechanisms and promote the possibility of exploring cellular behavior in the presence of strong gradients or fast changes in homogeneous conditions.

Enhanced secretion of growth factors from ADSCs using an enzymatic antioxidant hydrogel in inflammatory environments and its therapeutic effect

A catalytic ROS-scavenging hydrogel (HGel) was developed to enhance the growth factor secretion and the therapeutic efficacy of human adipose-derived stem cells (hADSCs) in inflammatory environments. The HGel is composed of heparin and hyaluronic acid, further functionalized with hemin to endow superoxide dismutase and catalase activities. The functionalization of hemin enables the HGel to effectively scavenge ROS (superoxide and H2O2), thereby protecting encapsulated hADSCs from oxidative stress and maintaining their metabolic activities. As a result, the HGel enhanced growth factor secretion of hADSCs in inflammatory conditions compared to non-functionalized, bare heparin/hyaluronic acid hydrogel (Gel). The therapeutic efficacy of the hADSC-encapsulated HGel (C/HGel) was evaluated in a diabetic wound model. The C/HGel significantly accelerated wound closure, reduced ROS levels, mitigated inflammation, and promoted angiogenesis compared to the hADSC-encapsulated Gel (C/Gel) as well as the HGel itself. The HGel has the potential to be utilized as an excellent cell carrier for stem cell therapy in various inflammatory diseases. Overall, this study demonstrated a strategy of enhancing growth factor secretion from stem cells using catalytic antioxidant hydrogels for superior regenerative effects in cell therapy.

ZnO-Rutin nanostructure as a potent antibiofilm agent against Pseudomonas aeruginosa

Pseudomonas aeruginosa is a common human pathogen that is resistant to multiple antibiotics due to its ability to form biofilms. Developing novel nanoformulations capable of inhibiting and removing biofilms offers a promising solution for controlling biofilm-related infections. In this study, we investigated the anti-biofilm activity of rutin-conjugated ZnO nanoparticles (ZnO-Rutin NPs) in pathogenic strains of P. aeruginosa. The synthesized ZnO-Rutin NPs had amorphous shapes with sizes ranging from 14 to 100 nm. The broth microdilution assay revealed that ZnO-Rutin NPs, with an MIC value of 2 mg/mL, exhibit greater antimicrobial activity than ZnO NPs and rutin alone. Based on crystal violet staining, the biofilm inhibition rate by ½ MIC of the conjugated nanoparticles was recorded at above 90%. The significant reduction in exopolysaccharide (62.75–66.37%) and alginate (38.3–57.61%) levels, as well as the formation of thin biofilms in the ZnO-Rutin NP-treated group, confirmed the anti-biofilm potential of these nanoparticles. Additionally, a significant decrease in the metabolic activity and viable cells of mature biofilms was observed after exposure to the conjugated nanoparticles. Furthermore, ZnO-Rutin NPs considerably attenuated the expression of the Las-Rhl quorum-sensing transcriptional regulator genes (lasR and rhlR) in P. aeruginosa by 0.39–0.40 and 0.25–0.42 folds, respectively. This work demonstrated that ZnO-Rutin NPs are remarkably capable of inhibiting the initial stage of biofilm formation and eradicating mature biofilms, suggesting they could be a useful agent for treating P. aeruginosa biofilm-related infections.

Relationship between physicochemical properties, non-volatile substances, and microbial diversity during the processing of dry-cured Spanish mackerel.

To meet the demand of consumers for high-quality dry-cured fish. This study investigates the relationship between microbial diversity and the changes in physicochemical properties and non-volatile flavor compounds of dry-cured Spanish mackerel (DCSM) throughout the curing process. Our findings demonstrate that moisture content significantly decreased during curing, while NaCl generally increased. The nitrite level of 1.52mg/kg, meeting national safety standards. Additionally, there was a significant increase in hardness and chewiness. The synergistic effect of glutamic acid (Glu), alanine (Ala), and histidine (His) with inosine monophosphate (IMP), adenosine monophosphate (AMP) and guanosine monophosphate (GMP) enhanced the umami taste. Proteobacteria and Photobacteria are the main microorganisms of DCSM at the phylum and genus levels. Proteobacteria and Photobacteria are the main microorganisms of DCSM at the phylum and genus levels. Photobacterium, Moritella, and Pseudomonas were positively correlated with AMP, GMP, Ala, and Glu. And negatively correlated with nitrite and TBARS. These findings suggest that specific microorganisms positively influence the quality of DCSM through their metabolic activities. This research enhances our understanding of flavor formation mechanisms and provides critical insights for optimizing DCSM processing and quality control.

Combined application of earthworms and plant growth promoting rhizobacteria improve metal uptake, photosynthetic efficiency and modulate secondary metabolites levels under chromium metal toxicity in Brassica juncea L

Chromium (Cr) toxicity impairs essential morphological and metabolic activities in plants. The present investigation was carried out to evaluate the beneficial role of plant growth promoting rhizobacterial strains namely Pseudomonas aeruginosa (M1), Burkholderia gladioli (M2) and earthworms (Eisenia fetida) in alleviating Cr toxicity in 10 days old Brassica juncea L. The findings delineated that addition of earthworms and PGPR restored growth, boosted Cr uptake and showed upregulation of metal transporter genes (SULTR 1-4). Supplementation of rhizospheric amendments reinstated Cr induced impairment in photosynthetic attributes. Gaseous exchange attributes, the efficiency of PS II, the content of total phenols, anthocyanin and flavonoids was enhanced with application of earthworms along with PGPR. Confocal imaging of primary photosynthetic pigment (chlorophyll), accessory photosynthetic pigment (carotenoids) and total phenols showed maximum fluorescence with combined inoculation of earthworms and both microbial strains (M1M2). The gene expression analysis revealed that Phyotene synthase (PSY), Photosystem II core protein psb A, psb B were down regulated in Cr stressed seedlings which upon supplementation with earthworms and PGPR were upregulated. Further, Phenylalanine ammonialyase (PAL), chalcone synthase (CHS) were upregulated with addition of earthworms and PGPR. Increased nitric oxide content, enhanced activity and upregulation of nitrate reductase (NR) gene was observed with addition of PGPR and earthworms

Thermal Management and Biocompatibility in Dry Machining: An Experimental Study of ZrO2-Based Cutting Tool for Bone Machining

This paper aims to assess the thermal properties and biocompatibility of zirconia-based bio ceramic cutting tools for bone surgery compared to stainless steel (SS316L) tools. Because of their biocompatibility, materials such as zirconia (ZrO2) are now widely utilized to reconstruct and replace bone tissue. The study compares wet and dry machining to analyze the effects of temperature and cell behaviour. By performing a quantitative MTT (yellow 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide) proliferation assay, the current study showed that ZrO2 had higher cell viability and metabolic activity than SS316L. The experiments included primary chondrocyte cells from chicken femoral condyles incubated at 37°C and 5% CO2 with increased cell survival and proliferation in the presence of ZrO2. Thermal performance was evaluated on a CNC vertical milling machine with the help of K-type thermocouples to measure the maximum (Tmax) and average (Tmean) temperature. ZrO2-based tools had resulted in lower Tmax and Tmean throughout the experiment regardless of the cutting parameters, which minimize the thermal injury and improve surgical results. Saline irrigation in wet machining helped in reducing temperature peaks, while dry machining had the advantages of not polluting the environment and being cheaper. Due to its low thermal conductivity and hardness, ZrO2 can be used as an effective material for metal tools in surgical operations to minimize thermal effect and increase the tool lifespan.

Critical considerations for co-administering rivaroxaban and vonoprazan: unveiling potential pharmacokinetic interactions

To study the effects of metabolic enzyme activity inhibition and genetic polymorphisms on the pharmacokinetics and pharmacodynamics of rivaroxaban, we established an in vitro enzymatic reaction system to screen for inhibitors, and used the UPLC-MS/MS method to detect the levels of rivaroxaban and its metabolite M2-1. Additionally, in vivo pharmacokinetic-pharmacodynamic studies were conducted using Sprague-Dawley rats. Human recombinant CYP2J2 baculosomes were prepared using a baculovirus-insect expression system to investigate the impact of genetic polymorphisms on rivaroxaban metabolism through enzyme kinetics methods. The results demonstrated that acid-suppressing drugs strongly inhibited the metabolism of rivaroxaban in vitro. Among them, vonoprazan significantly increased the systemic exposure of rivaroxaban in vivo, while also prolonging prothrombin time, likely due to the competitive binding of vonoprazan and rivaroxaban to CYP2J2. Moreover, the genetic polymorphisms of CYP2J2 determined the metabolic characteristics of rivaroxaban and the inhibitory potency of vonoprazan. Overall, our findings suggest that vonoprazan-induced inhibition of CYP2J2 activity can affect the pharmacokinetics and pharmacodynamics of rivaroxaban, with the extent of inhibition determined by the genetic polymorphism of CYP2J2. These insights have important implications for the precise management of rivaroxaban in humans.

Effect of dietary incorporation of defatted yellow mealworm larvae as an alternative protein source on growth, digestive, antioxidant, metabolic enzyme activities, hepatic histomorphology and immunity in pangasius (Pangasianodon hypophthalmus)

Effect of dietary incorporation of defatted yellow mealworm larvae as an alternative protein source on growth, digestive, antioxidant, metabolic enzyme activities, hepatic histomorphology and immunity in pangasius (Pangasianodon hypophthalmus)

Uncovering the Heterogeneity of Signaling Pathways in Skin Cutaneous Melanoma: Insights into Prognostic Values and Immune Interactions.

Signaling pathways play crucial roles in tumor cells. However, functional heterogeneity of signaling pathways in skin cutaneous melanoma (SKCM) has not been established. Based on a recent computational pipeline, pathway activities between SKCM and normal samples were identified. The results showed that high activities in 12 pathways were associated with poor prognoses, while high activities in 17 pathways were associated with favorable prognoses. Interestingly, elevated metabolic pathway activity was unfavorable, whereas elevated immune activity was favorable for SKCM. Unfavorably elevated metabolic pathways strongly correlated with Wnt/beta-catenin signaling. Conversely, favorable pathways, such as glycosaminoglycan biosynthesis and keratan sulfate, were strongly correlated with anti-tumor pathways. Moreover, the activities of favorable pathways were strongly positively correlated with infiltrating CD8+ T cells, macrophages M1, immune score, and stromal score, all of which were favorable for SKCM. Taken together, our study provides insights into the characteristics of several pathways in SKCM.

Complexation of starch and konjac glucomannan during screw extrusion exhibits obesity-reducing effects by modulating the intestinal microbiome and its metabolites.

Dietary interventions have been shown to improve gut health by altering the gut flora, preventing obesity, and mitigating inflammatory disorders. This study investigated the benefits of a rice starch-konjac glucomannan (ERS-KGM) complex, produced via screw extrusion, for gut health and obesity prevention. Analyzed through in vitro starch digestion, scanning electron microscopy, and structural analysis, the ERS-KGM complex exhibited a notable increase in resistant starch content due to its well-ordered structure. When administered to mice on a high-fat diet for 8 weeks, the ERS-KGM complex significantly reduced body weight, white adipose tissue mass, adipocyte size, and food intake while increasing water consumption. It also improved glucose metabolism, insulin sensitivity, and lipid profiles by lowering serum triglycerides and total glycerol content. Enhanced metabolic biomarkers and enzyme activities were observed, specifically involving glycerophospholipid metabolism. It decreased the activities of aldehyde dehydrogenase, lactate dehydrogenase, and amino acid transaminase while increasing antioxidant enzymes like glutathione peroxidase and superoxide dismutase. Additionally, it elevated glycogen and positively altered gut microbiota by enriching Firmicutes, Desulfobacterota, and Bifidobacterium. This change enhanced the ability to degrade specific compounds and elevated the concentrations of short-chain fatty acids in feces. These findings suggest that the ERS-KGM complex could serve as a dietary supplement for obesity prevention.

Phase partitioning of the neutrophil oxidative burst is coordinated by accessory pathways of glucose metabolism and mitochondrial activity.

Neutrophils are a part of the innate immune system and produce reactive oxygen species (ROS) to extinguish pathogens. The major source of ROS in neutrophils is NADPH oxidase, which is fueled by NADPH generated via the pentose phosphate pathway; however, it is unclear how other accessory glucose metabolism pathways and mitochondrial activity influence the respiratory burst. We examined the temporal dynamics of the respiratory burst and delineated how metabolism changes over time after neutrophil activation. Bone marrow-derived neutrophils were stimulated with phorbol 12-myristate 13-acetate, and the respiratory burst was measured via extracellular flux analysis. Metabolomics experiments utilizing 13C6-glucose highlighted the activation of glycolysis as well as ancillary pathways of glucose metabolism in activated neutrophils. Phorbol 12-myristate 13-acetate stimulation acutely increased 13C enrichment into glycerol 3-phosphate (G3P) and citrate, whereas increases in 13C enrichment in the glycogen intermediate, UDP-hexose, and end products of the hexosamine and serine biosynthetic pathways occurred only during the late phase of the oxidative burst. Targeted inhibition of the G3P shuttle, glycogenolysis, serine biosynthesis, and mitochondrial respiration demonstrated that the G3P shuttle contributes to the general magnitude of ROS production; that glycogen contributes solely to the early respiratory burst; and that the serine biosynthetic pathway activity and complex III-driven mitochondrial activity influence respiratory burst duration. Collectively, these results show that the neutrophil oxidative burst is highly dynamic, with coordinated changes in metabolism that control the initiation, magnitude, and duration of ROS production.

Creating Physiological Cell Environments In Vitro: Adjusting Cell Culture Media Composition and Oxygen Levels to Investigate Mitochondrial Function and Cancer Metabolism.

In vitro and ex vivo studies are crucial for mitochondrial research, offering valuable insights into cellular mechanisms and aiding in diagnostic and therapeutic strategies. Accurate in vitro models rely on adequate cell culture conditions, such as the composition of culture media and oxygenation levels. These conditions can influence energy metabolism and mitochondrial activities, thus impacting studies involving mitochondrial components, such as the effectiveness of anticancer drugs. This chapter focuses on practical guidance for creating setups that replicate in vivo microenvironments, capturing the original metabolic context of cells. We explore protocols to better mimic the physiological cell environment, promote cellular reconfiguration, and prime cells according to the modeled context. The first part is dedicated to the use of human dermal fibroblasts, which are a promising model for pre-clinical mitochondrial research due to their adaptability and relevance to human mitochondrial physiology. We present an optimized protocol for gradually adjusting extracellular glucose levels, which demonstrated significant mitochondrial, metabolic, and redox remodeling in normal adult dermal fibroblasts. The second part is dedicated to replication of tumor microenvironments, which are relevant for studies targeting cellular energy metabolism to inhibit tumor growth. Currently available physiological media can mimic blood plasma metabolome but not the specific tumor microenvironment. To address this, we describe optimized media formulation and oxygenation protocols, which can simulate the tumor microenvironment in cell culture experiments. Replicating in vivo microenvironments in in vitro and ex vivo studies can enhance our understanding of cellular processes, facilitate drug development, and advance personalized therapeutics in mitochondrial medicine.

Enzymatic browning of button mushrooms during postharvest cold chain circulation

This study aimed to investigate the molecular mechanism of browning of postharvest button mushrooms during cold chain circulation. Transcriptomic techniques based on RNA-seq sequencing data were used on the basis of sensory evaluation and determination of physiological and biochemical indexes. The differentially expressed genes (DEGs) related to quality deterioration and enzymatic browning of mushrooms in different stages of the postharvest precooling, cold chain shipping, and simulated cold shelf life were identified by GO functional annotation and KEGG pathway metabolic pathway analysis. These were subsequently verified by quantitative real-time polymerase chain reaction (RT-PCR). The results indicated that the quality changes were not significant during precooling and cold chain shipping (4–8 h) but were pronounced during the simulated cold shelf life (12°C ± 1°C) due to accelerated primary metabolic pathways involving glycolysis and organic acid utilization, leading to noticeable quality degradation. The analysis of selected DEGs through GO and KEGG pathway annotations revealed that the main genes related to browning included polyphenol oxidase (AGABI2DRAFT_194055), tyrosinase (AGABI2DRAFT_191532), peroxidases (AGABI2DRAFT_115586, AGABI2DRAFT_239410586, and AGABI2DRAFT_200291), and superoxide dismutase (AGABI2DRAFT_194955 and AGABI2DRAFT_207393), all of which were either significantly upregulated or downregulated. The validation by RT-PCR confirmed that these findings were consistent with the transcriptomic data. The combination of sensory scores, changes in physiological and biochemical indicators, and bioinformatics analysis revealed the effect of the modulation of energy metabolism and related enzymatic activities on the quality degradation and enzymatic browning of button mushrooms during the postharvest cold chain circulation.