Uptake Process Research Articles

Cage Architecture and Reactivity are Preserved in Cysteine‐mutated Ferritin

The role of solvent‐exposed cysteines as reactive sites for bioconjugation with a variety of metal drugs or fluorescent probes is emerging in the use of human H‐ferritin (HuHf) as a nanocarrier for targeting various tumor cell lines. Here, we have investigated the role of these residues in controlling the structural stability and ferroxidase activity by analyzing the properties of three variants: C90A, C90AC102A, and C130A. Protein folding and cage assembly were unchanged. Ferroxidase activity was also unaffected, indicating that these cysteines are not involved in either the catalytic activity or the overall iron(II) uptake process. For comparison, activity measurements were also performed on two derivatives containing the solvent‐exposed cysteine residues.

The efflux system CdfX exports zinc that cannot be transported by ZntA in Cupriavidus metallidurans.

Cupriavidus metallidurans is able to survive exposure to high concentrations of transition metals, but is also able to grow under metal starvation conditions. A prerequisite of cellular zinc homeostasis is a flow equilibrium combining zinc uptake and efflux processes. The mutant strain ∆e4 of the parental plasmid-free strain AE104 with a deletion of all four chromosomally encoded genes of previously known efflux systems ZntA, CadA, DmeF, and FieF was still able to efflux zinc in a pulse-chase experiment, indicating the existence of a fifth efflux system. The gene cdfX, encoding a protein of the cation diffusion facilitator (CDF) family, is located in proximity to the cadA gene, encoding a P-type ATPase. Deletion of cdfX in the ∆e4 mutant resulted in a further decrease in zinc resistance. Pulse-chase experiments with radioactive 65Zn(II) and stable-isotope-enriched 67Zn(II) provided evidence that CdfX was responsible for the residual zinc efflux activity of the mutant strain ∆e4. Reporter gene fusions with cdfX-lacZ indicated that the MerR-type regulator ZntR, the main regulator of zntA expression, was responsible for zinc- and cadmium-dependent upregulation of cdfX expression, especially in mutant cells lacking one or both of the previously characterized efflux systems, ZntA and CadA. Expression of zntR also proved to be controlled by ZntR itself as well as by zinc and cadmium availability. These data indicate that the cdfX-cadA region provides C. metallidurans with a backup system for the zinc-cadmium-exporting P-type ATPase ZntA, with CdfX exporting zinc and CadA cadmium.IMPORTANCEBacteria have evolved the ability to supply the important trace element zinc to zinc-dependent proteins, despite external zinc concentrations varying over a wide range. Zinc homeostasis can be understood as adaptive layering of homeostatic systems, allowing coverage from extreme starvation to extreme resistance. Central to zinc homeostasis is a flow equilibrium of zinc comprising uptake and efflux reactions, which adjusts the cytoplasmic zinc content. This report describes what happens when an imbalance in zinc and cadmium concentrations impairs the central inner-membrane zinc efflux system for zinc by competitive inhibition for this exporter. The problem is solved by activation of Cd-exporting CadA or Zn-exporting CdfX as additional efflux systems.

Understanding the crucial role of phosphate and iron availability in regulating root nodule symbiosis.

The symbiosis between legumes and nitrogen-fixing bacteria (rhizobia) is instrumental in sustaining the nitrogen cycle and providing fixed nitrogen to the food chain. Both partners must maintain an efficient nutrient exchange to ensure a successful symbiosis. This mini-review highlights the intricate phosphate and iron uptake and homeostasis processes taking place in legumes during their interactions with rhizobia. The coordination of transport and homeostasis of these nutrients in host plants and rhizobia ensures an efficient nitrogen fixation process and nutrient use. We discuss the genetic machinery controlling the uptake and homeostasis of these nutrients in the absence of rhizobia and in symbiotic conditions with this soil bacteria. We also highlight the genetic impact of the availability of phosphate and iron to coordinate the activation of the genetic programs that allow legumes to engage in symbiosis with rhizobia. Finally, we discuss how the transcription factor Phosphate Starvation Response (PHR) might be a crucial genetic element to integrate the nitrogen, iron, and phosphate plant's needs while interacting with rhizobia. Understanding the coordination of the iron and phosphate uptake and homeostasis can lead us to better harness the ecological benefits of the legume-rhizobia symbiosis, even under adverse environmental conditions.

Exosomal miRNA as biomarker in cancer diagnosis and prognosis: A review.

Exosomes, which are extracellular vesicles with a diameter ranging from 40 to 160 nm, are abundantly present in various body fluids. Exosomal microRNA (ex-miR), due to its exceptional sensitivity and specificity, has garnered significant attention. Notably, ex-miR is consistently detected in almost all bodily fluids, highlighting its potential as a reliable biomarker. This attribute of ex-miR has piqued considerable interest in its application as a diagnostic tool for the early detection, continuous monitoring, and prognosis evaluation of cancer. Given the critical role of exosomes and their cargo in cancer biology, this review explores the intricate processes of exosome biogenesis and uptake, their multifaceted roles in cancer development and progression, and the potential of ex-miRs as biomarkers for tumor diagnosis and prognosis.

Modular Nano-Antigen Display Platform for Pigs Induces Potent Immune Responses.

Multivalent presentation of antigens using nanoparticles (NPs) as a platform is an effective strategy to enhance the immunogenicity of subunit vaccines and thus induce a high level of organismal immune response. Our previous results showed that pre-existing porcine circovirus type 2 (PCV2) antibodies could increase the antibody levels of nanoparticle vaccines carried in PCV2 VLPs. Here, we have established a generalized nanoantigen display platform, Cap-Cat virus-like particles (VLPs). By combining PCV2 VLPs with the modular linker element SpyTag003/SpyCatcher003 system, four porcine-derived viral protective antigens with different sizes and multimeric structures: the PRRSV B-cell epitope, the PEDV COE monomer, the CSFV E2 dimer, and the SIV HA trimer were efficiently demonstrated to elicit a strong immune response in mice. Crucially, the modification of antigens by the Cap-Cat VLPs platform enhanced the Th2 response and improved the Th1 response. The use of the platform demonstrates that HA antigen protects against lethal attacks by influenza viruses and reduces viral load in the lungs. We have demonstrated that the Cap-Cat VLPs platform demonstrates that antigens enhance the immune response by improving the processes of DC uptake, transport, lymph node (LN) localization, and immune cell activation. This "plug-and-display" assembly strategy facilitates the use of the Cap-Cat VLPs nanoantigen display platform for more applications and thus facilitates the development of more efficient, general-purpose porcine subunit vaccines.

Amine-functionalized soy protein/graphene oxide aerogel for efficient removal of multiple sugar-derived contaminants (SDCs): Full life cycle exploration and interaction simulation

Sugar-derived contaminants (SDCs) pose significant environmental hazards and safety concerns, emerging as urgent issue. Using amine-modified soy protein (SPI) and graphene oxide (GO), an environment-friendly aerogel (PSPI/PGO) was synthesized to efficiently remove multiple SDCs. The equilibrium adsorption capacities of PSPI/PGO for melanoidins, caramels, and saccharin were 1124.2, 291.1, and 399.3 mg/g, respectively, surpassing those of previously proposed materials. A series of characterizations and experiments demonstrated that the porous PSPI/PGO exhibited high hydrophilicity, nontoxicity, excellent thermal stability, and sustainable capture properties. Emerging dynamic models (i.e., AOAS, EXT-INT, and LF-PC-AS) and multiple quantum chemical theory calculations (ESPL, ALIE, FMO, IGMH, and HSA) further revealed the capture of each SDC onto PSPI/PGO was driven predominantly by charge interactions, followed by H-bonding and intermolecular interactions. PSPI/PGO acts as an H-bonding acceptor in a diverse range of uptake processes for each SDC. The applicability of PSPI/PGO for treating real wastewater has been validated. The full lifecycle exploration of PSPI/PGO (including soil burial degradation tests, wastewater treatment, and garlic hydroponic experiments using depleted PSPI/PGO) underscores its considerable biocompatibility and potential for industrial applications.

A Synopsis on CO2 Capture by Synthetic Hydrogen Bonding Receptors.

Carbon dioxide (CO2) is one of the most abundant greenhouse gases in Earth's atmosphere and responsible for global warming. Therefore, aerial CO2 capture and sequestration has become a major task for human community. Though several adsorbents for CO2 including activated carbon, zeolites, metal-organic frameworks (MOFs), and other surface-modified porous materials are well developed, the supramolecular approaches using synthetic hydrogen-bonding receptors are less explored. This review article highlights the synthetic development of various artificial receptors and their properties toward fixation of aerial CO2 as carbonate (CO3 2-), bicarbonate (HCO3 -), or carbamate (-NHCOO-/>NCOO-) ions, induced by excess fluoride (F-) or hydroxide (OH-) ions as their tetrabutylammonium salts. The utilization of encapsulated carbonate/bicarbonate/carbamate complexes in anion exchange metathesis for separation of oxyanions from aqueous solutions are also discussed. In addition, the release of CO2 and regeneration of receptor molecules are described in a number of occasions. Most importantly, the formation of anion complexes as crystalline materials in solid-state is described in terms of supramolecular chemistry and correlated with their solution-state properties. Finally, the types of receptors containing various functional groups are scrutinized in CO2 uptake, storage, and release processes and hints of endeavours for future research are delineated.

Preparation and characterization of chitosan graphene oxide nanocomposite for the removal of 17-β-estradiol sulfate from water: kinetics, thermodynamics and simulation studies

The presence of 17-β-estradiol sulfate residue in water is of great concern due to its hazardous nature (endocrine disruptor and carcinogen). For this, chitosan was used with graphene oxide to prepare chitosan graphene oxide nanocomposite. This material was characterized and used as an adsorbent for the removal of 17-β-estradiol sulfate residue in water. This adsorbent showed a rapid, efficient, and environmentally friendly method of 17-β-estradiol sulfate removal from water. The optimal conditions for maximum removal were 93.6% (4.68 mg/g) with 2500 µg/L of 17-β-estradiol sulfate, 30 min of agitation, 0.50 g/L of graphene oxide chitosan nanocomposite, a pH of 7.0, and temperature of 25 °C. The thermodynamic parameters confirmed the spontaneity and exothermic nature of the 17-β-estradiol sulfate uptake process. The kinetic study revealed a first-order reaction, with the mechanism of uptake attributed to liquid film diffusion. The supra-molecular interaction between β-estradiol and graphene oxide chitosan nanocomposite was elucidated, highlighting the pivotal role of two hydrogen bonds with binding affinities of −6.80 and −7.03 kcal/mole for the first and second hydrogen bonds. This method is speedy, efficacy, and environmentally friendly; making it applicable for the removal of β-estradiol from water in diverse water systems.

Process optimization of victoria blue dye removal using polypyrrole-encapsulated zirconium oxide: Mechanistic pathway and economic assessment

In this study, an organometallic composite, namely a polypyrrole-encapsulated zirconium oxide (ZrO2/PPy) nanocomposite, was developed and used to eliminate Victoria blue dye (VB) from water system. Specific surface area of the ZrO2/PPy obtained from BET study was observed to be 61.822 m2/g. Solution pH of 7.0, ZrO2/PPy nanocomposite dose of 0.8 g/L, sonication period of 40 min and initial VB dye concentration of 50 mg/L were chosen as optimal test parameters, at which 86.23 (±1.15) % of VB dye elimination was observed. The VB dye uptake process follows pseudo-second-order kinetic model and Langmuir isotherm model, with the later providing the maximum VB dye adsorption capacity of ZrO2/PPy nanocomposite as 238.09 mg/g. Thermodynamics study suggests the spontaneous (ΔGo< 0) and endothermic (ΔHo> 0) nature of the adsorption study. Food processing wastewater causes maximum hindrance (∼20 (±0.90) % −25 (±1.03) %) in the VB dye uptake process while the presence of phosphate (PO43−) ions can create highest interference (∼17 (±0.93) % −19 (±1.08) %) in the VB dye uptake process. At the optimum test parameter values (adsorbent dose: 1.3 g/L, initial VB dye concentration: 20 mg/L, sonication period: 70 min) as suggested by response surface methodology (RSM), maximum VB dye elimination of ∼96 % was observed. Electrostatic attraction, π–π interaction and hydrogen bond formation are amongst the major uptake mechanisms. Regeneration study indicates ∼19 (±1.36) % of decrease in VB dye elimination (%) after fifth cycle of reuse. The lab scale and industrial scale fabrication expense of 1.0 kg of ZrO2/PPy nanocomposite were obtained as 75.74 and 22.20 USD, respectively. The findings of this study suggest the potential of ZrO2/PPy nanocomposite as an effective and economically viable adsorbent to eliminate VB dye from wastewater.

Insoluble Acyclic Cucurbit[n]uril-Type Receptors Capture Iodine from the Vapor Phase.

Nuclear energy makes large contributions toward meeting global energy needs, but societal concerns remain high given the impacts of the intended release of radioactive materials including 129I and 131I. In this paper we explore the use of a homologous series of acyclic CB[n] type hosts (H1 - H4) as adsorbents of iodine from the vapor phase. We find that H2 - H4, but not H1 - perform well in this application with uptake capacities of 2.2 g g-1, 1.5g g-1, and 1.9g g-1, respectively. The chemisorptive uptake process involves partial oxidation of catechol walled H2 to quinone walled host and capture of I3- and I5-. Solid H2 can be regenerated by treatment with Na2S2O4 and reused at least five times. The x-ray crystal structure of H2 is also reported.

Structural changes of Natronomonas pharaonis halorhodopsin in its late photocycle revealed by solid-state NMR spectroscopy

Natronomonas pharaonis halorhodopsin (NpHR) is a light-driven Cl− inward pump that is widely used as an optogenetic tool. Although NpHR is previously extensively studied, its Cl− uptake process is not well understood from the protein structure perspective, mainly because in crystalline lattice, it has been difficult to analyze the structural changes associated with the Cl− uptake process. In this study, we used solid-state NMR to analyze NpHR both in the Cl−-bound and -free states under near-physiological transmembrane condition. Chemical shift perturbation analysis suggested that while the structural change caused by the Cl− depletion is widespread over the NpHR molecule, residues in the extracellular (EC) part of helix D exhibited significant conformational changes that may be related to the Cl− uptake process. By combining photochemical analysis and dynamic nuclear polarization (DNP)-enhanced solid-state NMR measurement on NpHR point mutants for the suggested residues, we confirmed their importance in the Cl− uptake process. In particular, we found the mutation at Ala165 position, located at the trimer interface, to an amino acid with bulky sidechain (A165V) significantly perturbs the late photocycle and disrupts its trimeric assembly in the Cl−-free state as well as during the ion-pumping cycle under the photo-irradiated condition. This strongly suggested an outward movement of helix D at EC part, disrupting the trimer integrity. Together with the spectroscopic data and known NpHR crystal structures, we proposed a model that this helix movement is required for creating the Cl− entrance path on the extracellular surface of the protein and is crucial to the Cl− uptake process.

Removal of Pb2+ and Cu2+ from artificial geothermal brine by zeolite at various salinity and temperature conditions

Natural zeolite (predominantly clinoptilolite - Ca) was tested for application in geothermal facilities to remove copper (Cu2+) and lead (Pb2+) from formation fluids. Batch and dynamic flow-through (only for lead ions) experiments were performed at different salinities (I = 0.1 and 1 mol/L) in NaCl or CaCl2 solutions at up to 115 °C (batch experiments) and up to 130 °C (flow-through experiments), respectively. The batch experiments resulted in an uptake of up to 24 % at an initial concentration of 0.3 g/L and up to 93 % at 0.03 g/L of Pb2+ and 115 °C. For Cu2+, the uptake reached 100 % from initial 0.004 g/L. The presence of CaCl2 in the solution matrix reduced the uptake of the heavy metals as compared to the NaCl matrix. The Pb2+ uptake by zeolite granulates at dynamic flow-through conditions at 130 °C was 52 % of the initial value of 20.7 mg/L during the 180 min experimental time. Based on the results from batch experiments the data fitting indicated a site density of monovalent exchange sites of 3.0 ± 2.6 mmol/g solid and a cation exchange capacity (CEC) of 295 ± 26 meq/100 g zeolite. The Pb2+ uptake process by zeolite gave a KD value of log K = 1.53. These calculations were not possible for Cu2+ uptake indicating that the uptake mechanisms of Cu2+ at high salinities are too complex to be simulated.To explain the uptake processes at given conditions various structural analysis were performed. Infrared spectroscopy indicated a cation exchange of lighter ions in the crystal structure of zeolite by the heavier ions Cu2+ and Pb2+ at 650 to 750 cm−1. After the treatment with heavy metals, two new bands were detected at 2902 and 2982 cm−1, which were not observed in the natural zeolite. With X-ray diffraction (XRD) new crystalline phases were detected in the treated zeolite samples that could be attributed in case of Pb2+ uptake to cottunite (PbCl2) and laurionite (PbOHCl) and in the case of Cu2+ uptake to Cu2Cl(OH)3 and CuCl2. The simulated G(r)s supported these observations regarding Pb2+ uptake. Using electron microscopy methods, both mechanisms (ion exchange and mineral precipitation) were confirmed: the formation of new Pb2+ and Cu2+ containing mineral phases on the surface of the zeolite granules and the uniform distribution of chloro-coordinated complexes of Cu2+ and Pb2+ on the pore surfaces inside the zeolite.

Soil Water Flow Affected by Vegetation Root Water Uptake in the Semiarid Region of Mu Us Sandy Land, China

ABSTRACTVegetation plays an important role in the management of water resources and of the terrestrial vegetation degradation in semiarid regions of China. Detailed descriptions of the actual hydrological process of vegetation root water uptake (RWU) are lacking, and the dynamics of interfaces involved in the process of RWU have not received enough attention. A field in situ experiment with bare land and vegetated land was implemented to investigate soil water flow in vadose zones affected by vegetation RWU. The results revealed that, with the influence of RWU, the soil moisture content was redistributed and impacted evaporation and infiltration; therefore, even the roots were driven to utilize groundwater under intense potential evapotranspiration and water stress. Notably, the thicker vadose zones were beneficial for preserving water resources for bare land, but Salix reduced soil water storage by 1191.13 L compared with bare land, which was adverse for water resource development in semiarid regions. The results provide the basis for the protection of the vegetation environment and water resource management in arid regions.

Accounting for the mechanical response of the cell membrane during the uptake of random nanoparticles

In order to improve the efficiency of the delivery of cancer treatments to cancer cells, the cellular uptake of nanoparticles (NPs), used as drug delivery systems, is numerically investigated through a mechanical approach. The objective is to optimize the NP's mechanical and geometrical properties to enhance their entry into cancer cells while avoiding benign ones. In previous studies, these properties are modeled as constant during the process of cellular uptake. However, recent observations of the displacement of the membrane's constituents towards the region in the cell membrane where the uptake of the NPs takes place show that the mechanical properties of the membrane vary during this process. Reason for writing The important contribution of adhesion to the wrapping process is already well documented in literature. It is therefore crucial to model this parameter properly as the conclusions made with a constant adhesion model may not be accurate compared to reality. Methodology Based on the existing knowledge on the reaction of membrane constituents to interaction with NPs, a 3-parameter sigmoidal function, accounting for the delay, amplitude, and speed of the reaction, has been used to model the evolution of adhesion. A variance-based sensitivity analysis has then been performed in order to quantify the influence of these parameters on the outputs of the model. Results It was found that the introduction of a variable adhesion tends to alter the predictions of endocytosis of NPs. The contribution of the amplitude and delay is respectively 0.32 and 0.43 times as important as that of the NP's aspect ratio, which is the prominent parameter. The influence of the slope of the transition is the least important parameter and does not appear to contribute to endocytosis. Implications Hence, models of the cellular uptake of NPs should use a variable, instead of constant, adhesion in order a representative as possible of the behavior of the cell membrane. The predictions are different from those obtained using a model with constant adhesion.

Searching for Protein Off-Targets of Prostate-Specific Membrane Antigen-Targeting Radioligands in the Salivary Glands.

Background: Prostate specific membrane antigen (PSMA)-targeted radioligand therapies represent a highly effective treatment for metastatic prostate cancer. However, high and sustain uptake of PSMA-ligands in the salivary glands led to dose limiting dry mouth (xerostomia), especially with α-emitters. The expression of PSMA and histologic analysis couldn't directly explain the toxicity, suggesting a potential off-target mediator for uptake. In this study, we set out to search for possible off-target non-PSMA protein(s) in the salivary glands. Methods: A machine-learning based quantitative structure activity relationship (QSAR) model was built for seeking the possible off-target(s). The resulting target candidates from the model prediction were subjected to further analysis for salivary protein expression and structural homology at key regions required for PSMA-ligand binding. Furthermore, cellular binding assays were performed utilizing multiple cell lines with high expression of the candidate proteins and low expression of PSMA. Finally, PSMA knockout (PSMA-/-) mice were scanned by small animal PET/MR using [68Ga]Ga-PSMA-11 for in-vivo validation. Results: The screening of the trained QSAR model did not yield a solid off-target protein, which was corroborated in part by cellular binding assays. Imaging using PSMA-/- mice further demonstrated markedly reduced PSMA-radioligand uptake in the salivary glands. Conclusion: Uptake of the PSMA-targeted radioligands in the salivary glands remains primarily PSMA-mediated. Further investigations are needed to illustrate a seemingly different process of uptake and retention in the salivary glands than that in prostate cancer.

189 Association of the liver phosphoproteome with divergent dry matter intake in finishing beef steers

Abstract As the need for improving the sustainability of the beef industry increases, optimizing feed efficiency is of the utmost importance. The liver has a central role in nutrient metabolism, and for ruminants particularly, it is essential for providing glucose through gluconeogenesis via substrates such as propionate, lactate, and glycerol. Further, through cell signaling and vagal afferent signals, the liver acts to stimulate and inhibit dry matter intake (DMI). Thus, the objective of this study was to investigate alterations in the phosphoproteome of finishing beef steers in relation to divergent DMI to identify changes in the abundance of signaling proteins. Angus steers [n = 57; initial body weight (BW) = 518 ± 27 kg] underwent a 63-d intake trial utilizing an Insentec Roughage Intake Control System (Hokofarm Group, Emmeloord, The Netherlands). Prior to beginning the trial, liver biopsy samples were collected from all steers. Samples from steers with the greatest and least DMI (n = 8 each) were utilized for phosphoproteomic analysis. Liver protein was isolated and labeled with isobaric tandem mass tagging reagents. Samples were enriched for phosphopeptides using immobilized metal affinity chromatography and subsequently analyzed using high-performance liquid chromatography tandem mass spectrometry. Spectral data were searched in the National Center for Biotechnology Information Bos taurus protein database using MaxQuant (version 2.2.0.0; Max Planck Inst., Munich, Germany), and the data were analyzed using Perseus (version 2.0.10.0; Max Planck Inst.). Two sample t-tests were conducted to determine the difference in phosphopeptide abundance between steers with high and low DMI. A total of 16,365 phosphopeptides were identified, and 287 were differentially expressed (False Discovery Rate &amp;lt; 0.05). In addition, 2,777 phosphopeptides were differentially expressed based on an unadjusted P &amp;lt; 0.05 which were used for enrichment analysis of Gene Ontology processes and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways using the Database for Annotation, Visualization, and Integrated Discovery. The background for this analysis was all identified phosphopeptides. Gene ontology terms enriched included processes related to phosphorylation activity, intracellular signal transduction, response to insulin, kinase activity, and signaling protein binding. Enriched KEGG pathways included pathways related to insulin signaling, such as AMPK signaling, mTOR signaling, and MAPK signaling. Further, pathways related to glycolysis and gluconeogenesis, glucagon signaling, insulin resistance, carbon metabolism, and various other signaling pathways were also enriched. These results suggest a link between the liver phosphoproteome and DMI, indicating that divergent DMI is associated with alterations in signaling pathways related to nutrient uptake and metabolic processes.

Bacterial lipopolysaccharide inhibits free thiamin uptake along the intestinal tract via interference with membrane expression of thiamin transporters 1 and 2.

This study examined the effect of exposure of small and large intestinal epithelial cells to the bacterial lipopolysaccharide (LPS) on uptake of free form of vitamin B1, i.e., thiamin. The intestinal tract encounters two sources of thiamin: diet and the gut microbiota. Absorption of thiamin in both the small and large intestine occurs via a carrier-mediated process that involves thiamin transporters 1 and 2 (THTR-1 and -2). Complementary in vitro (human duodenal epithelial HuTu-80 cells and human colonic epithelial NCM460 cells), in vivo (mice), and ex vivo (human primary differentiated enteroid and colonoid monolayers) models were used. The results showed that exposure to LPS causes a significant inhibition in carrier-mediated [3H]-thiamin uptake by small and large intestinal epithelia, with no change in the levels of expression of THTR-1 and -2 mRNAs and their total cellular proteins. However, a significant decrease in the fractions of the THTR-1 and -2 proteins that are expressed at the cell membranes of these epithelial cells was observed. These effects of LPS appeared to involve a protein kinase A (PKA) signaling pathway as activating this pathway caused a reversal in the inhibition of thiamin uptake and level of expression of its transporters at the cell membrane. These findings demonstrate that exposure of gut epithelia to LPS (a situation that occurs under different pathological conditions) leads to inhibition in thiamin uptake due to a decrease in level of expression of its transporters at the cell membrane that is likely mediated via a PKA signaling pathway. NEW & NOTEWORTHY This study shows that the exposure of gut epithelial cells to bacterial LPS negatively impact the uptake process of the free form of vitamin B1 (i.e., thiamin). This appears to be mediated via suppression in the level of thiamin transporters 1 and 2 (THTR-1 and -2) expression at the cell membrane and involves a protein kinase A (PKA) signaling pathway.

Raman imaging unveils heme uptake in endothelial cells

Heme released from damaged and senescent red blood cells (RBCs) may contribute to oxidant-mediated cell injury. One of the recently investigated physiological processes, essential in preventing the inflammatory impact of labile heme, is its uptake from the bloodstream by endothelial cells (ECs). In this study, we investigated heme uptake by ECs starting from the model studies on the in vitro cellular level, through the endothelium layer on the ex vivo murine aortic tissues. As the cellular model, Human Aortic Endothelial Cells (HAECs) were chosen, and the concentration of labile heme was adjusted so to avoid the excessive toxic effect of the labile heme. We utilized label-free Raman imaging with two different excitation wavelengths to capture the uptake process in situ and characterize the oxidation state of the iron ion in the intercalated heme. The phenomenon of heme uptake was demonstrated in both, the healthy control C57Bl/6J and FVB animals, as well as in mice with developed atherosclerosis (ApoE/LDLR−/− mice). In the presented work, we presented for the first time Raman-based evidence on the heme uptake process by endothelial cells in both, in vitro and ex vivo systems.

A Novel Bi-Directional Channel for Nutrient Uptake across Mycobacterial Outer Envelope.

Nutrients are absorbed by special transport proteins on the cell membrane; however, there is less information regarding transporters across the mycobacterial outer envelope, which comprises dense and intricate structures. In this study, we focus on the model organism Mycolicibacterium smegmatis, which has a cell envelope similar to that of Mycobacterium tuberculosis, as well as on the TiME protein secretion tube across the mycobacterial outer envelope. We present transcriptome results and analyze the protein compositions of a mycobacterial surface envelope, determining that more transporters and porins are induced to complement the deletion of the time gene in Mycolicibacterium smegmatis. The TiME protein is essential for nutrient utilization, as demonstrated in the uptake experiments and growth on various monosaccharides or with amino acids as the sole carbon source. Its deletion caused bacteria to be more sensitive to anti-TB drugs and to show a growth defect at an acid pH level, indicating that TiME promotes the survival of M. smegmatis in antibiotic-containing and acidic environments. These results suggest that TiME tubes facilitate bi-directional processes for both protein secretion and nutrient uptake across the mycobacterial outer envelope.

The novel performance and adsorption mechanism of synthesized modified zirconium-based metal-organic frameworks for resource recovery from wastewater

Phosphorous (P) is an indispensable nutrient popularly employed to fertilize agricultural farms. However, its overuse in farming leads to excessive discharge in agricultural runoff, causing eutrophication. To prevent harm to the environment, it is necessary to remove P from wastewater. Adsorption is one of the ways to achieve this goal. In this study, using a solvothermal process, UiO-66-NH2 was successfully modified/codoped with aluminum (Al) and magnesium (Mg). The Al/Mg-codoped UiO-66-NH2 was characterized using scanning electron microscopy, X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The study also investigated various adsorption factors, including temperature, pH, initial phosphate concentration, sorbent dosage, reaction time, and coexisting components. The findings demonstrated that the sorption process was predominantly based on chemical interactions, as evidenced by the Langmuir model (R2 > 0.99) and pseudo-second order (R2 > 0.99) analyses that fit well with experimental findings. The sorption capacity value was determined to be 117.6 mg P/g or 360.73 mg PO4/g. Thermodynamic results suggested the spontaneous and endothermic nature of P uptake process. Additionally, this research demonstrated the effective utilization of adsorbent for up to six regeneration cycles and recovery of adsorbed P using sodium hydroxide.