Complex Substrates Research Articles

Importance of lysosomal storage diseases in rheumatology

Lysosomal storage diseases are agroup of rare hereditary metabolic diseases. Due to adeficiency of lysosomal enzymes, complex substrates accumulate in the lysosomes of various organs. Depending on the affected enzyme, this results in clinically variable and chronic progressive multiorgan diseases. Diagnosis is often delayed. As clinical symptoms include the musculoskeletal system, an awareness of lysosomal storage diseases is of relevance to (pediatric) rheumatologists. This article is focused on Mucopolysaccharidosis typeI‑S, Mucolipidosis typeIII, Gaucher disease and Fabry disease. When suspecting alysosomal storage disease, enzyme activity should be determined in dried blood spots or leukocytes. For some diseases, specific biomarkers can additionally be analyzed. Diagnosis should be confirmed by genetic testing. As causal treatment options are available for three of the presented diseases, a timely diagnosis is very important.

Molecular dynamics simulations shed light into the donor substrate specificity of vertebrate poly-alpha-2,8-sialyltransferases ST8Sia IV

BackgroundSialic acids are essential monosaccharides influencing several biological processes and disease states. The sialyltransferases catalyze the transfer of Sia residues to glycoconjugates playing critical roles in cellular recognition and signaling. Despite their importance, the molecular mechanisms underlying their substrate specificity, especially between different organisms, remain poorly understood. Recently, the human ST8Sia IV, a key enzyme in the synthesis of polysialic acids, was found to accept only CMP-Neu5Ac as a sugar-donor, whereas the whitefish Coregonus maraena enzyme showed a wider donor substrate specificity, accepting CMP-Neu5Ac, CMP-Neu5Gc, and CMP-Kdn. However, what causes these differences in donor substrate specificity is unknown. MethodsComputational approaches were used to investigate the structural and biochemical determinants of the donor substrate specificity in ST8Sia IV. Accurate structural models of the human and fish ST8Sia IV catalytic domains and their complexes with three sialic acid donors (CMP-Neu5Ac, CMP-Neu5Gc, and CMP-Kdn) were generated. Subsequently, molecular dynamics simulations were conducted to analyze the stability and interactions within these complexes and identify differences in complex stability and substrate binding sites between the two ST8Sia IV. ResultsOur MD simulations revealed that the human enzyme effectively stabilizes CMP-Neu5Ac, whereas CMP-Neu5Gc and CMP-Kdn are unstable and explore different conformations. In contrast, the fish ST8Sia IV stabilizes all three donor substrates. Based on these data, we identified the key interacting residues for the different Sias parts of the substrate donors. General significanceThis work advances our knowledge of the enzymatic mechanisms governing sialic acid transfer, shedding light on the evolutionary adaptations of sialyltransferases.

First experiences with protected VT ablation using surgical Impella 5.5

Abstract Introduction Ablation of ventricular arrhythmias (VA) is still challenging due to the complex substrate of the underlying heart disease. Depending on specific risk factors acute hemodynamic decompensation during or after VT ablation procedures may occur and hemodynamic support may be required. Protected VA ablation with different devices has been evaluated but associated complications like bleeding, vascular closure or weaning from the device have been restrictive. We present data on a dedicated approach to patients with anticipated hemodynamic deterioration using preventive surgical Impella support. Method 5 patients (2 female) underwent protected VT ablation under our standardized protocol. Indication for Impella support was severely impaired left ventricular function and multiple medical therapy refractory ventricular arrhythmias. 4 patients had conventional VT ablation before. Mean age was 66,8 years, mean CHADSVASC 4,4, 1 patient with non-ischemic cardiomyopathy (CMP), 1 with hypertrophic non-obstructive CMP, 3 patients with ischemic CMP. Mean EF was 20%, mean mixed venous saturation was 36 %, mean PAINESD score 27. In all patients a 5.5. Impella was implanted surgically 1 day before planned VT ablation via the right subclavian artery. VT ablation procedure started with substrate mapping, VT induction and activation mapping of the inducible VT to identify the critical VT isthmus. Ablation was directed to dissection of the critical isthmus of inducible VAs and elimination of all late potentials within low voltage areas. The Impella device was explanted after weaning off the hemodynamic support. Results Implantation of Impella 5.5 was successfully performed in all patients in general anesthesia without any complication via surgical approach. Specifically, no access site vascular complications were noted. In 4 patients the VT ablation procedure was performed in analgosedation, 1 patient in GA as this patient was intubated due to recurrent VA requiring defibrillation. Mean procedure time was 125 min, radiation time 1,3 min, inducible VTs 1,3 , median 2 morphologies. In all patients all inducible VTs could be eliminated, in 1 patient polymorphic VA was still inducible at the end of the procedure. Impella was explanted after mean 5,2 days (3-11 days). No complications occurred. All patients were discharged alive on heart failure medication and in 2 patients with amiodaron. At a mean follow up of 3.5 months, all patients are alive without VA recurrence and heart failure decompensation. Conclusion Surgical Impella implantation for protected VT ablation in severe heart failure patients is feasible and allows for effective VT mapping and ablation. Access site safety and protection for heart failure decompensation in addition to the possibility of individually mobilisation and weaning after the procedure make this protocol an attractive option. Prospective evaluation of standardized indication is needed.

High selectivity and anti-interference molecularly imprinted polymer based on spheroidal carbonized polymer dots for effective sulfadiazine sodium removal

Although several methods for enhancing the selectivity of molecularly imprinted polymers (MIPs) have been reported, their effects on complex substrates remain unsatisfactory. In this study, a customised 1-vinyl-3-hydroxyethylimidazolium tetrafluoroborate ionic liquid with a vinyl double bond polymerizable unit and an F-atom recognition unit was employed as a precursor carbon source to prepare unique spherical carbonised polymer dots (CPDs-F) through an incomplete carbonisation process using the one-step hydrothermal method. Then used it as a novel functional monomer, sulfadiazine sodium (SDS), as a template to synthesize the SDS-imprinted material CPDs-F@MIP in aqueous media. The results indicated that the obtained CPDs-F@MIP exhibited excellent selectivity for the template, with an imprinting factor of up to 6.39, surpassing that of the MIPs prepared with chain functional monomers 2.12–4.76 times. The selective adsorption of the template molecule, SDS (selectivity coefficient: approximately 2.615–43.149), was not significantly influenced by the coexistence of contaminants with various structural characteristics. The maximum adsorption capacity reached 61.06 mg g−1. After at least twenty applications, the adsorption capability of CPDs-F@MIP did not decrease significantly. Finally, the prepared CPDs-F@MIP were used as solid-phase extraction adsorbents in combination with high-performance liquid chromatography, and the anti-interference ability and selective adsorption performance of CPDs-F@MIP in six actual water samples were investigated. Additionally, an accurate, reliable method for detecting SDS in environmental water was established (limit of detection of 0.2 μg L−1, and the recoveries ranged from 91.79% to 111.32%). Imprinting materials prepared using spherical functional monomers significantly enhance their selective recognition ability in complex media and provide new ideas for the preparation and application of novelty imprinting materials with superior performance.

Improved uniformity of atomic-layer-deposited HfO2 film along the length of glass monocapillary with high length-diameter ratio

It has been a difficult to deposit a uniform film on the inner surface of monocapillary due to the high length-diameter ratio. Atomic layer deposition (ALD) shows great potential to coat conformal film on complex substrates. However, it is still a challenge to coat uniform film along the length of the capillary for regular deposition parameters. In this work, HfO2 film was deposited inside monocapillary via ALD. The film uniformity along the monocapillary was investigated by cross-section scanning electron microscope (SEM) images and the bond states of one of the HfO2 films were studied via X-ray photoelectron spectroscopy (XPS). Using the routine deposition parameters, the gas flowing through the monocapillary is controlled to be small, large and medium qualitatively by covering some of the inlets or outlets, changing the connection between monocapillary and outlets simply. SEM results demonstrate that smooth HfO2 film with uniform thickness can be acquired on the inner surface of monocapillary with length-diameter ratio 200 (length 10 cm and inner diameter 0.5 mm). XPS results show that Hf hydroxide is generated when the gas flowing through the monocapillary is large.

Research progress of persulfate activation technology.

Persulfate-based advanced oxidation processes (PS-AOPs) have been widely investigated by academia and industry due to their high efficiency and selectivity for the removal of trace organic pollutants from complex water substrates. PS-AOPs have been extensively studied for the degradation of pesticides, drugs, halogen compounds, dyes, and other pollutants. Utilizing bibliometric statistics, this review presents a comprehensive overview of persulfate-based advanced oxidation technology research over the past decade. The number of published articles about persulfate activation has steadily increased during this time, reflecting extensive international collaboration. Furthermore, this review introduces the most widely employed strategies for persulfate activation reported in the past 10years, including carbon material activation, photocatalysis, transition metal activation, electrochemical activation, ultrasonic activation, thermal activation, and alkali activation. Next, the potential activation mechanisms and influencing factors, such as persulfate dosage during activation, are discussed. Finally, the application of PS-AOPs in wastewater treatment and in situ groundwater treatment is examined. This review summarizes the previously reported experiences of persulfate-based advanced oxidation technology and presents the current application status of PS-AOPs in organic pollution removal, with the aim of avoiding misunderstandings and providing a solid foundation for future research on the removal of organic pollutants.

Air‐Stable Bis‐Cyclometallated Iridium Catalysts for Ortho‐Directed C(sp2)−H Borylation

AbstractWe report a class of isolable bis‐cyclometallated iridium precatalysts (ImIr) and their use in regioselective ortho−C−H borylation of aromatic, heteroaromatic, acrylic, and aliphatic systems. The catalysts consist of two imine ligands and an acetate coordinated to an iridium (III) center. The isolable character of ImIr warrants its compatibility with high‐throughput experimentation, a prerequisite for applications in late‐stage functionalization (LSF) of complex substrates. Initial mechanistic studies point towards an inner‐sphere mechanism involving bis‐cyclometallated species shedding light on the general mechanistic understanding of ortho‐selective C−H borylations.

Electrochemical Benzylic C(sp3)-H Imidation Enabled by Benzoic Acid Derived Radicals.

We developed an electrochemical approach for benzylic C(sp3)-H imidation by virtue of the in situ generated oxygen-centered radicals (OCRs). The electrochemical imidation provides a complementary approach to giving distinct imide products compared with previous acyloxylation products. This protocol exhibits good site selectivity and broad substrate generality. Moreover, the utility of the OCR-mediated protocol was extended to the electrochemical oxidation of silane, and its robustness was also highlighted by the imidation of complex substrates, which would otherwise be inaccessible for previous approaches. A plausible reaction mechanism was proposed to rationalize the experimental observations.

Advances in the Homogeneously Catalyzed Hydrogen Production from Biomass Derived Feedstocks: a Review.

Biomass‐derived feedstocks for hydrogen production are crucial as an alternative to fossil fuel especially in those areas where green electricity and clean water are scarce. In this framework the transformation of simple (formic acid, alcohols) and more complex (polyalcohols, sugars and cellulose) bio‐derivatives in pure hydrogen is recognized as a promising approach. Parallel to great effort in heterogeneous catalysis, milder molecular systems represent a more selective eye for alternative solutions and mechanistic insights. In the present review the introduction summarizes the challenges in the catalytic utilization of biomass‐derived feedstocks, followed by the advances in homogeneously catalyzed hydrogen production from different substrates which will cover formic acid, with oustanding efficiency with noble metals and promising results with earth abundant ones and alcohols and polyalcohols, with particular emphasis to the development of heterogenized systems, ligand assisted catalysts and bi‐catalytic synergistic solutions which allow to avoid base and to promote catalyst stability and recyclability. In the last part, description of hydrogen production from more complex substrates, such as sugars and cellulose, will show the role of molecular complexes in main and side reactions. Critical comments on the reported advances are provided along the whole discussion.

Crystal structure of activating sulfotransferase SgdX2 involved in biosynthesis of secondary metabolite sungeidine

Microorganisms synthesize a plethora of complex secondary metabolites, many of which are beneficial to human health, such as anticancer agents and antibiotics. Among these, the Sungeidines are a distinct class of secondary metabolites known for their bulky and intricate structures. They are produced by a specific biosynthetic gene cluster within the genome of the soil-dwelling actinomycete Micromonospora sp. MD118. A notable enzyme in the Sungeidine biosynthetic pathway is the activating sulfotransferase SgdX2. In this pathway, SgdX2 mediates a key sulfation step, after which the product undergoes spontaneous dehydration to yield a Sungeidine compound. To delineate the structural basis for SgdX2's substrate recognition and catalytic action, we have determined the crystal structure of SgdX2 in complex with its sulfate donor product, 3′-phosphoadenosine 5′-phosphate (PAP), at a resolution of 1.6 Å. Although SgdX2 presents a compact overall structure, its core elements are conserved among other activating sulfotransferases. Our structural analysis reveals a unique substrate-binding pocket that accommodates bulky, complex substrates, suggesting a specialized adaptation for Sungeidine synthesis. Moreover, we have constructed a substrate docking model that provides insights into the molecular interactions between SgdX2 and Sungeidine F, enhancing our understanding of the enzyme's specificity and catalytic mechanism. The model supports a general acid-base catalysis mechanism, akin to other sulfotransferases, and underscores the minor role of disordered regions in substrate recognition. This integrative study of crystallography and computational modeling advances our knowledge of microbial secondary metabolite biosynthesis and may facilitate the development of novel biotechnological applications.

Molecular imprinting-based triple-emission ratiometric fluorescence sensor with aggregation-induced emission effect for visual detection of doxycycline

The development of high-performance sensors for doxycycline (DOX) detection is necessary because its residue accumulation will cause serious harm to human health and the environment. Here, a novel tri-emission ratiometric fluorescence sensor was proposed by using “post-mixing” strategy of different emissions fluorescence molecularly imprinted polymers with salicylamide as dummy template (DMIPs). BSA was chosen as assistant functional monomer, and also acted as sensitizers for the aggregation-induced emission (AIE) effect of DOX. The blue-emitting carbon dots and the red-emitting CdTe quantum dots were separately introduced into DMIPs as the response signals. Upon DOX recognition within 2 min, blue and red fluorescence of the tri-emission DMIPs sensor were quenched while green fluorescence of DOX was enhanced, resulting in a wide range of color variations observed over bluish violet-rosered-light pink-orange-yellow-green with a detection limit of 0.061 μM. The sensor possessed highly selective recognition and was successfully applied to detect DOX in complicated real samples. Moreover, with the fluorescent color collection and data processing, the smartphone-assisted visual detection of the sensors showed satisfied sensitivity with low detection limit. This work provides great potential applications for rapid and visual detection of antibiotics in complex substrates.

Photocatalytic Synthesis of β-Keto Primary Chlorides by Selective Chlorocarbonylation of Olefins.

Functionalized primary alkyl chlorides are precursors to a plethora of scaffolds but their access from chemical feedstocks remains challenging. Herein, we report a concise dual Ni/photoredox catalytic protocol for regioselective chlorocarbonylation of unactivated alkenes that enables rapid access to β-keto primary chlorides. The catalytic process features an extensive substrate scope, scalability and functional group tolerance. The Ni/photocatalytic Cl⋅ generation and subsequent cross-coupling is implicated for the process based on the control experiments and DFT study. The synthetic utility of the protocol has been further corroborated through functionalization of complex substrates and modifications of the product.

Photocatalytic Synthesis of β‐Keto Primary Chlorides by Selective Chlorocarbonylation of Olefins

AbstractFunctionalized primary alkyl chlorides are precursors to a plethora of scaffolds but their access from chemical feedstocks remains challenging. Herein, we report a concise dual Ni/photoredox catalytic protocol for regioselective chlorocarbonylation of unactivated alkenes that enables rapid access to β‐keto primary chlorides. The catalytic process features an extensive substrate scope, scalability and functional group tolerance. The Ni/photocatalytic Cl⋅ generation and subsequent cross‐coupling is implicated for the process based on the control experiments and DFT study. The synthetic utility of the protocol has been further corroborated through functionalization of complex substrates and modifications of the product.

Sustainable production of biofuels using different microbial consortia: the state of the art

AbstractPopulation growth has generated an enormous increase in demand for energy and chemicals to supply goods and services and to maintain quality of life. Oil, coal, and natural gas are the primary sources of the chemicals and energy that directly impact the economy. However, the reserves of these resources are continuously reducing. New alternatives have emerged, including biotechnological tools such as microbial consortia (MC) to produce biofuels, chemicals such as organic acids, and processed foods. The diversity of MC as a biotechnological tool allows it to be used in complex substrates, opening the possibility of using other solid waste to implement consolidated bioprocesses (CPs). This review presents an overview of the uses of MC and CP for producing biofuels using different feedstocks.

Preparation of limonin monoclonal antibody and establishment of a sensitive icELISA for analyzing limonin in citrus and herbal samples

Limonin is an intensely bitter and highly oxidized tetracyclic triterpenoid secondary metabolite, which is abundant in the Rutaceae and Meliaceae, especially in Citrus. In order to detect limonin content in complex substrates such as citrus and traditional Chinese medicine, monoclonal antibodies specifically recognizing limonin were prepared and an indirect competitive enzyme-linked immunosorbent assay (icELISA) was established. The median inhibition concentration (IC50) was 5.40 ng/mL and the linear range was 1.25–23.84 ng/mL. The average recoveries from citrus peel and pulp samples were 95.9%–118.8% and 77.5%–113.1%, respectively. Moreover, the contents of limonin in 6 citrus samples and 4 herbal samples were analyzed by icELISA and UPLC-MS, and the results of the two methods were consistent. This validation is sufficient to demonstrate that the developed immunoassay is applicable for the detection of limonin in citrus and herbal samples and has the advantage of high efficiency, sensitivity, and convenience.

Habitat‐setting affects biodiversity while predation determines oyster survival on experimental oyster reefs

Foundation species are being restored into inherently variable landscapes with multiple, interspersed habitats. However, understanding of the influence of different neighbouring habitats on community assembly and the survival of restored species is limited, despite their significant potential to affect restoration outcomes. We tested how habitat‐setting (being next to seagrass, seagrass and mangroves, or unvegetated sediments) and predation (by meso‐ and/or large predators) influenced macroinvertebrate community assembly and the survival of juvenile Sydney rock oysters (Saccostrea glomerata) on experimental oyster reef units in the Port Hacking estuary, New South Wales, Australia. Each habitat‐setting produced a distinct macroinvertebrate community on experimental reefs, whereas predation had limited effects on community structure. Juvenile oysters were instead highly predated everywhere, and oyster predation was dominated by the large, transient fish Acanthropagrus australis. Our findings allow practitioners to predict and tailor the communities which establish on restored oyster reefs by strategically placing them next to different habitats. If sites have a high predation risk but require seeding for reefs to establish, then caging or complex substrates must be used to increase seeded oyster survival.

Assessing anaerobic microbial degradation rates of crude light oil with reverse stable isotope labelling and community analysis

Oil reservoirs represent extreme environments where anaerobic degradation profoundly influences oil composition and quality. Despite the common observation of biodegraded oil, the microbial degradation rates remain largely unknown. To address this knowledge gap, we conducted microcosm incubations with light oil as carbon source, original formation water and sulfate as electron acceptor, closely mimicking in situ conditions to assess oil degradation rates. Samples were taken from a newly drilled oil well to exclude contamination with injection water and allochthonous microorganisms. At the end of the incubations, microbial community analyses with 16S rRNA gene amplicon sequencing revealed the most prominent phyla as Desulfobacterota, Thermotogota, Bacteroidota, Bacillota (formerly Firmicutes), and Synergistota, collectively accounting for up to 44% of relative abundance. Ion chromatography and reverse stable isotope labeling were used to monitor sulfate reduction and CO2 evolution respectively. We calculated an average degradation rate of 0.35 mmol CO2 per year corresponding to 15.2 mmol CO2/mol CH2(oil) per year. This resembles to approximately 200 years to degrade one gram of oil under the applied, presumably ideal conditions. Factoring in the available oil-water-contact (OWC) zone within the incubations yielded a degradation rate of 120 g CH2 m−2 OWC per year, closely aligning with the modeled degradation rates typically observed in oil reservoirs. Moreover, our study highlighted the utility of the reverse stable isotope labeling (RSIL) approach for measuring complex substrate degradation at minute rates.

Evaporation-driven interfacial restructuring induces highly efficient methanogenesis of waste biomass

Methanogenesis of waste biomass (WB) is a promising method for global sustainable development, reduction of pollution and carbon emission levels, and recovering bioenergy. Unlike in the methanogenesis of organic wastewater, in which microbial cells come into direct contact with the dissolved substrate, the ‘solid–liquid–solid’ modes in WB and between WB and microbial cells, which involve numerous solid–liquid interfaces, greatly hinder the methanogenesis efficiency of WB. Amongst all WB, waste activated sludge is the most complex, poorly biodegradable and representative. Herein, we highlight the role of water evaporation-driven solid-liquid interfacial restructuring of sludge in determining its methanogenesis efficiency. Non-free water evaporation increased surface roughness and adhesion, and compressed pore structure with numerous capillaries in sludge, resulting in a new solid-liquid interface of sludge with great capillary force and highly ordered interfacial water molecules, which provides an extremely favourable condition for high mass transfer and proton-coupled electron transfer (PCET) in sludge. This restructuring was confirmed to induce the enhancement of solid–liquid interfacial noncovalent interactions and electron transfer efficiency in the subsequent methanogenesis process (P < 0.05), promoting the effective contact between the sludge substrate and microbial cells, thereby enriching the methanogenic consortia (i.e., Clostridia and Methanosarcina were increased by 290.0 % and 239.7 %, respectively) and improving the activities of key enzymes. Stable isotope tracing and metagenomic analysis further reveal that this restructuring promoted the participation of water molecules in the methane formation by PCET-driven release of protons from water, and enhanced main methanogenesis metabolic pathways, especially the metabolic pathway of CO2-reduction methanogenesis (+65.2 %), thereby resulting in a great advance in methane generation (+147 %, P < 0.001). The findings can provide a reference for regulating directional anaerobic biotransformation of water-rich multiphase complex substrates by interfacial restructuring inducement.

Transition-Metal-Free C-N Cross-Coupling Enabled by a Multifunctional Reagent.

We report the design and development of a transition-metal-free cross-coupling reaction of phenols and primary amines using a simple and readily available multifunctional reagent. The reactions work by induced proximity and electronic activation of both the nucleophile and the electrophile for net dehydrative C-N coupling reactions. Notably, the reactions do not involve the use of a transition metal for C-N bond formation, preactivation of the phenol electrophile, or exclusion of air or moisture. The mild conditions tolerate a broad range of functional groups and allow for this to be applied to the late-stage functionalization of complex substrates with a wide scope of coupling partners.

Recent Developments and Applications of Biocatalytic and Chemoenzymatic Synthesis for the Generation of Diverse Classes of Drugs.

Biocatalytic and chemoenzymatic biosynthesis are powerful methods of organic chemistry that use enzymes to execute selective reactions and allow the efficient production of organic compounds. The advantages of these approaches include high selectivity, mild reaction conditions, and the ability to work with complex substrates. The utilization of chemoenzymatic techniques for the synthesis of complicated compounds has lately increased dramatically in the area of organic chemistry. Biocatalytic technologies and modern synthetic methods are utilized synergistically in a multi-step approach to a target molecule under this paradigm. Chemoenzymatic techniques are promising for simplifying access to essential bioactive compounds because of the remarkable regio- and stereoselectivity of enzymatic transformations and the reaction diversity of modern organic chemistry. Enzyme kits may include ready-to-use, reproducible biocatalysts. Its use opens up new avenues for the synthesis of active therapeutic compounds and aids in drug development by synthesizing active components to construct scaffolds in a targeted and preparative manner. This study summarizes current breakthroughs as well as notable instances of biocatalytic and chemoenzymatic synthesis. To assist organic chemists in the use of enzymes for synthetic applications, it also provides some basic guidelines for selecting the most appropriate enzyme for a targeted reaction while keeping aspects like cofactor requirement, solvent tolerance, use of whole cell or isolated enzymes, and commercial availability in mind.