A hybrid photocatalytic system enables direct glucose utilization for methanogenesis.

Integration of methanogenic archaea with photocatalysts presents a sustainable solution for solar-driven methanogenesis. However, maximizing CH4 conversion efficiency remains challenging due to the intrinsic energy conservation and strictly restricted substrates of methanogenic archaea. Here, we report a solar-driven biotic-abiotic hybrid (biohybrid) system by incorporating cadmium sulfide (CdS) nanoparticles with a rationally designed methanogenic archaeon Methanosarcina acetivorans C2A, in which the glucose synergist protein and glucose kinase, an energy-efficient route for glucose transport and phosphorylation from Zymomonas mobilis, were implemented to facilitate nonnative substrate glucose for methanogenesis. We demonstrate that the photo-excited electrons facilitate membrane-bound electron transport chain, thereby augmenting the Na+ and H+ ion gradients across membrane to enhance adenosine triphosphate (ATP) synthesis. Additionally, this biohybrid system promotes the metabolism of pyruvate to acetyl coenzyme A (AcCoA) and inhibits the flow of AcCoA to the tricarboxylic acid (TCA) cycle, resulting in a 1.26-fold augmentation in CH4 production from glucose-derived carbon. Our results provide a unique strategy for enhancing methanogenesis through rational biohybrid design and reprogramming, which gives a promising avenue for sustainably manufacturing value-added chemicals.

Magnetite nanoparticle coating chemistry regulates root uptake pathways and iron chlorosis in plants.

Understanding the fundamental interaction of nanoparticles at plant interfaces is critical for reaching field-scale applications of nanotechnology-enabled plant agriculture, as the processes between nanoparticles and root interfaces such as root compartments and root exudates remain largely unclear. Here, using iron deficiency-induced plant chlorosis as an indicator phenotype, we evaluated the iron transport capacity of Fe3O4 nanoparticles coated with citrate (CA) or polyacrylic acid (PAA) in the plant rhizosphere. Both nanoparticles can be used as a regulator of plant hormones to promote root elongation, but they regulate iron deficiency in plant in distinctive ways. In acidic root exudates secreted by iron-deficient Arabidopsis thaliana, CA-coated particles released fivefold more soluble iron by binding to acidic exudates mainly through hydrogen bonds and van der Waals forces and thus, prevented iron chlorosis more effectively than PAA-coated particles. We demonstrate through roots of mutants and visualization of pH changes that acidification of root exudates primarily originates from root tips and the synergistic mode of nanoparticle uptake and transformation in different root compartments. The nanoparticles entered the roots mainly through the epidermis but were not affected by lateral roots or root hairs. Our results show that magnetic nanoparticles can be a sustainable source of iron for preventing leaf chlorosis and that nanoparticle surface coating regulates this process in distinctive ways. This information also serves as an urgently needed theoretical basis for guiding the application of nanomaterials in agriculture.

Probing the Surface Layer Modulation on Archaeal Mechanics and Adhesion at the Single-Cell Level.

Addressing the challenge of understanding how cellular interfaces dictate the mechanical resilience and adhesion of archaeal cells, this study demonstrates the role of the surface layer (S-layer) in methanogenic archaea. Using a combination of atomic force microscopy and single-cell force spectroscopy, we quantified the impact of S-layer disruption on cell morphology, mechanical properties, and adhesion capabilities. We demonstrate that the S-layer is crucial for maintaining cell morphology, where its removal induces significant cellular enlargement and deformation. Mechanical stability of the cell surface is substantially compromised upon S-layer disruption, as evidenced by decreased Young's modulus values. Adhesion experiments revealed that the S-layer primarily facilitates hydrophobic interactions, which are significantly reduced after its removal, affecting both cell-cell and cell-bubble interactions. Our findings illuminate the S-layer's fundamental role in methanogen architecture and provide a chemical understanding of archaeal cell surfaces, with implications for enhancing methane production in biotechnological applications.

In Situ Probing of the Intrinsic Adhesion Strength of Single Anaerobic Microbial Cells.

Probing the single-cell mechanobiology in situ is imperative for microbial processes in the medical, industrial, and agricultural realms, but it remains a challenge. Herein, we present a single-cell force microscopy method that can be used to measure microbial adhesion strength under anaerobic conditions in situ. This method integrates atomic force microscopy with an anaerobic liquid cell and inverted fluorescence microscopy. We obtained the nanomechanical measurements of the single anaerobic bacterium Ethanoligenens harbinense YUAN-3 and the methanogenic archaeon Methanosarcina acetivorans C2A and their nanoscale adhesion forces in the presence of sulfoxaflor, a successor of neonicotinoid pesticides. This study presents a new tool for in situ single-cell force measurements of various anoxic and anaerobic species and provides new perspectives for evaluating the potential environmental risk of neonicotinoid applications in ecosystems.

Bubbles Expand the Dissemination of Antibiotic Resistance in the Aquatic Environment.

Antibiotic resistance is a global health challenge, and the COVID-19 pandemic has amplified the urgency to understand its airborne transmission. The bursting of bubbles is a fundamental phenomenon in natural and industrial processes, with the potential to encapsulate or adsorb antibiotic-resistant bacteria (ARB). However, there is no evidence to date for bubble-mediated antibiotic resistance dissemination. Here, we show that bubbles can eject abundant bacteria to the air, form stable biofilms over the air-water interface, and provide opportunities for cell-cell contact that facilitates horizontal gene transfer at and over the air-liquid interface. The extracellular matrix (ECM) on bacteria can increase bubble attachment on biofilms, increase bubble lifetime, and, thus, produce abundant small droplets. We show through single-bubble probe atomic force microscopy and molecular dynamics simulations that hydrophobic interactions with polysaccharides control how the bubble interacts with the ECM. These results highlight the importance of bubbles and its physicochemical interaction with ECM in facilitating antibiotic resistance dissemination and fulfill the framework on antibiotic resistance dissemination.

'Redeemed' or 'isolated': A systematic review of the experiences of older adults receiving a mild cognitive impairment diagnosis.

BACKGROUND: Understanding the experiences of older adults living with MCI can benefit healthcare professionals in diagnosing and implementing early interventions to delay cognitive decline. OBJECTIVE: To assess and synthesize qualitative research exploring the experience of older adults diagnosed with MCI. METHODS: PubMed, Embase, CINAHL, Web of Science, and PsycINFO databases were searched. Studies involving the experience of being diagnosed with MCI in older adults were included. Thomas and Harden's methodology of synthesizing qualitative studies was used. RESULTS: Eleven studies were included. Three themes were identified: perceived reality of the MCI diagnosis; emotional and psychological responses to the MCI label; coping engaged in parallel processing. Older adults had confusing perspectives on the MCI diagnosis, leading to complicated and diverse emotional reactions and coping measures. CONCLUSIONS: The relationship between perspectives, emotional reactions, and coping methods might be the key for healthcare professionals to break through the early diagnosis and intervention of MCI.

Model-based mid-infrared spectroscopy for on-line monitoring of volatile fatty acids in the anaerobic digester.

The performance of anaerobic digestion is significantly governed by the concentration of volatile fatty acids (VFAs). Though the titration and near-infrared spectroscopy have been used to measure the VFAs in the digester, there is still lack of the establishment of on-line monitoring of VFAs in practical application. An effective quantification method based on mid-infrared (MIR) spectroscopy was developed, and used to measure the concentrations of VFAs in the anaerobic bioreactor nondestructively in parallel. The wavelet denoising (WD) spectra were used as the spectral preprocessing option. Compared with other pretreatment methods, the established calibration model built by WD spectra showed satisfactory results. Further, the model was verified using high performance liquid chromatography (HPLC), and predictions were made using real reactor effluent samples. Based on this theoretical work, a set of equipment for the in-situ online monitoring of VFAs was designed, which has high feasibility and effectively solves the problems with the current VFAs online monitoring process. These results provide a new solution for on-line monitoring of the anaerobic digestion, and have great potential for practical application.

Understanding help-seeking decisions in people with subjective cognitive decline: A systematic review of qualitative studies.

OBJECTIVE: To synthesize the findings of qualitative research on help-seeking in people with subjective cognitive decline. METHODS: Relevant qualitative studies were identified by searching the PubMed, CINAHL, Ovid Medline, PsycInfo, Embase, and Web of Science databases. Studies that investigated help-seeking behavior in older adults with subjective cognitive decline were retrieved. The systematic review was conducted in line with JBI methodology for systematic reviews of qualitative evidence. RESULTS: 11 studies were included and three themes related to the process of help-seeking for cognitive problems emerged. These themes included: detected changes, challenges in identifying the need for help and decision to seek professional help. CONCLUSION: Making decisions to seek help for people with subjective cognitive decline is a multi-stage process. A better understanding of the complex psychological responses to subjective cognitive decline among older adults may help health care professionals to develop strategies to improve help-seeking in clinical practice.

Systematic review of physical exercise for patients with idiopathic inflammatory myopathies.

Idiopathic inflammatory myopathies (IIM) are systemic autoimmune connective tissue diseases. The safety and effectiveness of exercise for patients with idiopathic inflammatory myopathies remains unclear. This study aimed to systematically review the evidence for physical exercise among patients with idiopathic inflammatory myopathies. Relevant experimental studies were identified through searching the PubMed, Cochrane, Embase, Scopus, and CINAHL databases, and studies involving any type of physical exercise for ≥1 month were considered. The primary outcome was muscle strength, and the secondary outcomes included aerobic fitness, functional performance, health status, quality of life, activities of daily living, pain, and fatigue. Eight randomized controlled trials and thirteen nonrandomized uncontrolled trials were reviewed. Physical exercise appeared safe, with several positive effects. However, selection or allocation biases and small sample sizes affected the certainty of the evidence. While physical exercise appeared safe for patients with idiopathic inflammatory myopathies with several positive effects, studies of a higher methodological quality and involving patients with active disease are needed. Furthermore, to design optimal exercise programs, consistent and sensitive outcome measures are needed to facilitate comparisons of results from different studies.

Evaluation of nine active components of Lu-Jiao Fang in normal and hypertrophic rat myocardia via LC-MS/MS.

Lu-Jiao Fang (LJF), a traditional Chinese medicine prescription, can improve the cardiac function of chronic heart failure (CHF) patients; however, knowledge about the cardiac distribution of LJF, especially in CHF animal models, is rather limited. This work aimed to explore the cardiac distribution of LJF in pressure overload-induced CHF rats at the last gavage administration of LJF after 30 weeks of treatment. LC-MS/MS methods for analyzing nine active components (i.e. loganin, hesperidin, epimedin C, icariin, psoralen, isopsoralen, baohuoside I, morroniside and specnuezhenide) of LJF in cardiac tissue samples were established, and the components were then analyzed in left ventricular wall (LVW) and right ventricular wall (RVW) in parallel at same time point postdose for three dose groups. The results showed that most analytical component levels in LVW (hypertrophic myocardium) were only 39-74% of those in RVW (normal myocardium); however, psoralen and isopsoralen levels in LVW were equal to or even greater than the levels in RVW, suggesting that the hypertrophic myocardium tissue affinity of psoralen and isopsoralen might overcome the negative effect of decreased blood flow on distribution. This study indicated that the pathological state may influence drug distribution, and the efficacy of psoralen and isopsoralen for improving CHF deserves further investigation.

Antibody-free detection of cellular neddylation dynamics of Cullin1.

Neddylation is a posttranslational modification that regulates protein stability, activity, and subcellular localization. Here, we describe a new tool for exploring the neddylation cycle of cullin1 (Cul1) directly in a cellular context. This assay utilizes the NanoLuc® Binary Technology (NanoBiT) to monitor the covalent neddylation status of Cul1. A stable clonal cell line derived from HEK293 was developed that expressed a C-terminus LgBiT tagged-Cul1 and N-terminus SmBiT tagged-Nedd8. Using this cell line, we screened inhibitors that are known to disrupt Nedd8 biology and demonstrated that both inhibitors of Nedd8-activating enzyme (NAE) and Constitutive photomorphogenesis 9 signalosome (CSN) complex produce concentration and time dependent signal decreases and increases, respectively. The kinetics of both responses could be monitored in real time and demonstrated that modulation of the Nedd8 pathway occurs rapidly. Further characterization of the cellular components of this cell line was performed in order to quantify the various levels of Cul1, Nedd8 and NAE and determined to be near endogenous levels. There was no difference between control and stably transfected cell lines in viability studies of NAE and CSN inhibitors. Taken together, these results suggest that the NanoBiT assay can be used to monitor Cul1 neddylation specifically and in real time.

Substrate-assisted inhibition of ubiquitin-like protein-activating enzymes: the NEDD8 E1 inhibitor MLN4924 forms a NEDD8-AMP mimetic in situ.

The NEDD8-activating enzyme (NAE) initiates a protein homeostatic pathway essential for cancer cell growth and survival. MLN4924 is a selective inhibitor of NAE currently in clinical trials for the treatment of cancer. Here, we show that MLN4924 is a mechanism-based inhibitor of NAE and creates a covalent NEDD8-MLN4924 adduct catalyzed by the enzyme. The NEDD8-MLN4924 adduct resembles NEDD8 adenylate, the first intermediate in the NAE reaction cycle, but cannot be further utilized in subsequent intraenzyme reactions. The stability of the NEDD8-MLN4924 adduct within the NAE active site blocks enzyme activity, thereby accounting for the potent inhibition of the NEDD8 pathway by MLN4924. Importantly, we have determined that compounds resembling MLN4924 demonstrate the ability to form analogous adducts with other ubiquitin-like proteins (UBLs) catalyzed by their cognate-activating enzymes. These findings reveal insights into the mechanism of E1s and suggest a general strategy for selective inhibition of UBL conjugation pathways.

Improved Scheduling Mechanisms for Synchronous Information and Energy Transmission.

Wireless energy collecting technology can effectively reduce the network time overhead and prolong the wireless sensor network (WSN) lifetime. However, the traditional energy collecting technology cannot achieve the balance between ergodic channel capacity and average collected energy. In order to solve the problem of the network transmission efficiency and the limited energy of wireless devices, three improved scheduling mechanisms are proposed: improved signal noise ratio (SNR) scheduling mechanism (IS2M), improved N-SNR scheduling mechanism (INS2M) and an improved Equal Throughput scheduling mechanism (IETSM) for different channel conditions to improve the whole network performance. Meanwhile, the average collected energy of single users and the ergodic channel capacity of three scheduling mechanisms can be obtained through the order statistical theory in Rayleig, Ricean, Nakagami-m and Weibull fading channels. It is concluded that the proposed scheduling mechanisms can achieve better balance between energy collection and data transmission, so as to provide a new solution to realize synchronous information and energy transmission for WSNs.

Mechanistic study of Uba5 enzyme and the Ufm1 conjugation pathway.

E1 enzymes activate ubiquitin or ubiquitin-like proteins (Ubl) via an adenylate intermediate and initiate the enzymatic cascade of Ubl conjugation to target proteins or lipids. Ubiquitin-fold modifier 1 (Ufm1) is activated by the E1 enzyme Uba5, and this pathway is proposed to play an important role in the endoplasmic reticulum (ER) stress response. However, the mechanisms of Ufm1 activation by Uba5 and subsequent transfer to the conjugating enzyme (E2), Ufc1, have not been studied in detail. In this work, we found that Uba5 activated Ufm1 via a two-step mechanism and formed a binary covalent complex of Uba5∼Ufm1 thioester. This feature contrasts with the three-step mechanism and ternary complex formation in ubiquitin-activating enzyme Uba1. Uba5 displayed random ordered binding with Ufm1 and ATP, and its ATP-pyrophosphate (PPi) exchange activity was inhibited by both AMP and PPi. Ufm1 activation and Uba5∼Ufm1 thioester formation were stimulated in the presence of Ufc1. Furthermore, binding of ATP to Uba5∼Ufm1 thioester was required for efficient transfer of Ufm1 from Uba5 to Ufc1 via transthiolation. Consistent with the two-step activation mechanism, the mechanism-based pan-E1 inhibitor, adenosine 5'-sulfamate (ADS), reacted with the Uba5∼Ufm1 thioester and formed a covalent, tight-binding Ufm1-ADS adduct in the active site of Uba5, which prevented further substrate binding or catalysis. ADS was also shown to inhibit the Uba5 conjugation pathway in the HCT116 cells through formation of the Ufm1-ADS adduct. This suggests that further development of more selective Uba5 inhibitors could be useful in interrogating the roles of the Uba5 pathway in cells.

Chemical Dynamics of Selenium Nanoparticles in Archaeal Systems.

Methanogenic archaea, characterized by their cell membrane lipid molecules consisting of isoprenoid chains linked to glycerol-1-phosphate via ether bonds, exhibit exceptional adaptability to extreme environments. However, this distinct lipid architecture also complicates the interactions between methanogenic archaea and nanoparticles. This study addresses this challenge by exploring the interaction and transformation of selenium nanoparticles (SeNPs) within archaeal Methanosarcina acetivorans C2A. We demonstrated that the effects of SeNPs are highly concentration-dependent, with chemical stimulation of cellular processes at lower SeNPs concentrations as well as oxidative stress and metabolic disruption at higher concentrations. Notably, we observed the formation of a protein corona on SeNPs, characterized by the selective adsorption of enzymes critical for methylotrophic methanogenesis and those involved in selenium methylation, suggesting potential alterations in protein function and metabolic pathways. Furthermore, the intracellular transformation of SeNPs into both inorganic and organic selenium species highlighted their bioavailability and dynamic transformation within archaea. These findings provide vital insights into the nano-bio interface in archaeal systems, contributing to our understanding of archaeal catalysis and its broader applications.

Nitrogen Forms Regulate the Response of Microcystis aeruginosa to Nanoplastics at Environmentally Relevant Nitrogen Concentrations.

As essential primary producers, cyanobacteria play a major role in global carbon and nitrogen cycles. Though the influence of nanoplastics on the carbon metabolism of cyanobacteria is well-studied, little is known about how nanoplastics affect their nitrogen metabolism, especially under environmentally relevant nitrogen concentrations. Here, we show that nitrogen forms regulated growth inhibition, nitrogen consumption, and the synthesis and release of microcystin (MC) in Microcystis aeruginosa exposed to 10 µg/mL amino-modified polystyrene nanoplastics (PS-NH2) with a particle size of 50 nm under environmentally relevant nitrogen concentrations of nitrate, ammonium, and urea. We demonstrate that PS-NH2 inhibit M. aeruginosa differently in nitrate, urea, and ammonium, with inhibition rates of 51.87, 39.70, and 36.69%, respectively. It is caused through the differences in impairing cell membrane integrity, disrupting redox homeostasis, and varying nitrogen transport pathways under different nitrogen forms. M. aeruginosa respond to exposure of PS-NH2 by utilizing additional nitrogen to boost the production of amino acids, thereby enhancing the synthesis of MC, extracellular polymeric substances, and membrane phospholipids. Our results found that the threat of nanoplastics on primary producers can be regulated by the nitrogen forms in freshwater ecosystems, contributing to a better understanding of nanoplastic risks under environmentally relevant conditions.

Mechanistic studies on activation of ubiquitin and di-ubiquitin-like protein, FAT10, by ubiquitin-like modifier activating enzyme 6, Uba6.

Uba6 is a homolog of the ubiquitin-activating enzyme, Uba1, and activates two ubiquitin-like proteins (UBLs), ubiquitin and FAT10. In this study, biochemical and biophysical experiments were performed to understand the mechanisms of how Uba6 recognizes two distinct UBLs and catalyzes their activation and transfer. Uba6 is shown to undergo a three-step activation process and form a ternary complex with both UBLs, similar to what has been observed for Uba1. The catalytic mechanism of Uba6 is further supported by inhibition studies using a mechanism-based E1 inhibitor, Compound 1, which forms covalent adducts with both ubiquitin and FAT10. In addition, pre-steady state kinetic analysis revealed that the rates of UBL-adenylate (step 1) and thioester (step 2) formation are similar between ubiquitin and FAT10. However, distinct kinetic behaviors were also observed for ubiquitin and FAT10. FAT10 binds Uba6 with much higher affinity than ubiquitin while demonstrating lower catalytic activity in both ATP-PP(i) exchange and E1-E2 transthiolation assays. Also, Compound 1 is less potent with FAT10 as the UBL compared with ubiquitin in ATP-PP(i) exchange assays, and both a slow rate of covalent adduct formation and weak adduct binding to Uba6 contribute to the diminished potency observed for FAT10. Together with expression level analysis in IM-9 cells, this study sheds light on the potential role of cytokine-induced FAT10 expression in regulating Uba6 pathways.

Quantifiable analysis of cellular pathway inhibition of a Nedd8-activating enzyme inhibitor, MLN4924, using AlphaScreen.

Cellular effects of a Nedd8-activating enzyme (NAE) inhibitor, MLN4924, using the AlphaScreen format were explored. MLN4924 acts as a substrate-assisted inhibitor of NAE by forming a tight binding Nedd8-MLN4924 adduct. The inhibited enzyme can no longer transfer Nedd8 downstream to modify and activate the E3 cullin-RING ligases. This results in the stabilization of proteins regulated by the proteasome, leading to cell death. These studies monitored the endogenous cellular changes to NAE∼Nedd8 thioester, the formation of the Nedd8-MLN4924 adduct, and the reduction in the Cul1-Nedd8. Lysates derived from MLN4924-treated HCT116 cells showed that whereas the ß-subunit of NAE remained constant, reductions of both NAE∼Nedd8 thioester and Cul1-Nedd8 levels occurred with a concomitant rise of the adduct. Moreover, the formation of the Nedd8-MLN4924 adduct was approximately stoichiometric with the concentration of NAEß. Higher density 384-well cell-based assays illustrated the kinetics of enzyme inactivation across a wider range of MLN4924 concentrations, showing a rapid loss of NAE∼Nedd8 thioester and Cul1-Nedd8. The reduction of NAE∼Nedd8 thioester precedes the loss of Cul1-Nedd8 at twice the rate. Finally, these results clearly demonstrate the utility of the homogeneous assay for quantitative assessment of these endogenous cellular components in a 384-well plate in response to inhibition of NAE by MLN4924.

Using colloidal AFM probe technique and XDLVO theory to predict the transport of nanoplastics in porous media.

The plastic concentration in terrestrial systems is orders of magnitude higher than that found in marine ecosystems, which has raised global concerns about their potential risk to agricultural sustainability. Previous research on the transport of nanoplastics in soil relied heavily on the qualitative prediction of the mean-field extended Derjaguin-Landau-Verwey-Overbeek theory (XDLVO), but direct and quantitative measurements of the interfacial forces between single nanoplastics and porous media are lacking. In this study, we conducted multiscale investigations ranging from column transport experiments to single particle measurements. The maximum effluent concentration (C/C0) of amino-modified nanoplastics (PS-NH2) was 0.94, whereas that of the carboxyl-modified nanoplastics (PS-COOH) was only 0.33, indicating PS-NH2 were more mobile than PS-COOH at different ionic strengths (1-50 mM) and pH values (5-9). This phenomenon was mainly attributed to the homogeneous aggregation of PS-COOH. In addition, the transport of PS-NH2 in the quartz sand column was inhibited with the increase of ionic strength and pH, and pH was the major factor governing their mobility. The transport of PS-COOH was inhibited with increasing ionic strength and decreasing pH. Hydrophilicity/hydrophobicity-mediated interactions and particle heterogeneity strongly interfered with interfacial forces, leading to the qualitative prediction of XDLVO, contrary to experimental observations. Through the combination of XDLVO and colloidal atomic force microscopy, accurate and quantitative interfacial forces can provide compelling insight into the fate of nanoparticles in the soil environment.

Single bubble probe atomic force microscope and impinging-jet technique unravel the interfacial interactions controlled by long chain fatty acid in anaerobic digestion.

Anaerobic digestion of lipid-rich wastewater generally suffers from foaming induced by long chain fatty acid (LCFA). However, a systematic understanding of LCFA inhibition, especially the physical inhibition on interfacial interaction still remains unclear. Here, we combined bubble probe atomic force microscope and impinging-jet technique to unravel the interfacial interactions controlled by long chain fatty acids in anaerobic digestion. We showed that LCFA had a significant inhibition on methane production in anaerobic reactors for the inhibition of the conversion of VFAs to methane. By measuring the LCFA influence on methanogenic archaea Methanosarcina acetivorans C2A, the results demonstrated that methanogenesis was limited for substrates utilization but not metabolic pathways. The impinging-jet technique results indicated that LCFA enhanced bubble separation from anaerobic granules and reduced the bubble-bubble coalescence probability. In addition, the bubble probe atomic force microscope (AFM) revealed that LCFA enhanced the adhesion force between bubbles by enhancing electrical double layer (EDL) repulsion and decreasing hydrophobic interactions. Overall, these results complement framework of LCFA inhibition in anerobic digestion and provide a nanomechanical insight into the fundamental interfacial interactions related to bubbles in anaerobic reactors.