Fucoidans inhibited tau interaction and cellular uptake.

Tau spreading in Alzheimer's disease is mediated by cell surface heparan sulfate (HS). As a class of sulfated polysaccharides, fucoidans might compete with HS to bind tau, resulting in the cessation of tau spreading. The structural determinants of fucoidans for competition with HS binding to tau are not well understood. Sixty previously prepared fucoidans/glycans with different structural determinants were used to determine their binding abilities to tau using SPR and AlphaLISA. Finally, it was found that fucoidans had two fractions (sulfated galactofucan (SJ-I) and sulfated heteropolysaccharide (SJ-GX-3)), which exhibited strong binding abilities than heparin. Tau cellular uptake assays using wild type mouse lung endothelial cell lines were performed. It was shown SJ-I and SJ-GX-3 inhibited tau-cell interaction and tau cellular uptake, suggesting that fucoidans might be good candidates for inhibiting tau spreading. NMR titration mapped fucoidans binding sites, which could provide the theoretical basis for the design of tau spreading inhibitors.

Bio-inspired synthesis of amino acids modified sulfated cellulose nanofibrils into multivalent viral inhibitors via the Mannich reaction.

Virus cross-infection via surfaces poses a serious threat to public health. Inspired by natural sulfated polysaccharides and antiviral peptides, we prepared multivalent virus blocking nanomaterials by introducing amino acids to sulfated cellulose nanofibrils (SCNFs) via the Mannich reaction. The antiviral activity of the resulting amino acid-modified sulfated nanocellulose was significantly improved. Specifically, 1 h treatment with arginine modified SCNFs at a concentration of 0.1 g/mL led to a complete inactivation of the phage-X174 (reduction by more than three orders of magnitude). Atomic force microscope showed that amino acid-modified sulfated nanofibrils can bind phage-X174 to form linear clusters, thus preventing the virus from infecting the host. When we coated wrapping paper and the inside of a face-mask with our amino acid-modified SCNFs, phage-X174 was completely deactivated on the coated surfaces, demonstrating the potential of our approach for use in the packaging and personal protective equipment industries. This work provides an environmentally friendly and cost-efficient approach to fabricating multivalent nanomaterials for antiviral applications.

Unravelling the role of sulphate in reed development in urban freshwater lakes.

Many European lakes have suffered from reed die-back since the 1950s. Previous studies have concluded that this is due to a combination of several interacting factors, but possibly also a single threat with high impact might be responsible for the phenomenon. In this study, we investigated 14 lakes in the Berlin area differing in reed development and sulphate concentration from 2000 to 2020. To unravel the decline of reed beds in some of the lakes with coal mining activities in the upper watershed, we compiled a comprehensive data set. Thus, the littoral zone of the lakes was divided into 1302 segments considering the reed ratio relative to segment area, water quality parameters, littoral characteristics and bank usage of the lakes which all have been monitored for 20 years. We ran two-way panel regressions with a within estimator to consider the spatial variation between and within the segments over time. The regression results revealed a strong negative relationship between reed ratio and sulphate concentrations (p<0.001) as well as tree shading (p<0.001) and a strong positive relationship with brushwood fascines (p<0.001). Taking only sulphate into account, reeds would have covered an additional area of 5.5 ha or 22.6% in 2020 (total reed area: 24.3 ha) in the absence of increased sulphate concentrations. In conclusion, changes in water quality upstream the catchment cannot be ignored in the development of management plans for downstream lakes.

Antiviral and Antibacterial Sulfated Polysaccharide-Chitosan Nanocomposite Particles as a Drug Carrier.

Drug delivery system (DDS) refers to the method of delivering drugs to the targeted sites with minimal risk. One popular strategy of DDS is using nanoparticles as a drug carrier, which are made from biocompatible and degradable polymers. Here, nanoparticles composed of Arthrospira-derived sulfated polysaccharide (AP) and chitosan were developed and expected to possess the capabilities of antiviral, antibacterial, and pH-sensitive properties. The composite nanoparticles, abbreviated as APC, were optimized for stability of morphology and size (~160 nm) in the physiological environment (pH = 7.4). Potent antibacterial (over 2 µg/mL) and antiviral (over 6.596 µg/mL) properties were verified in vitro. The pH-sensitive release behavior and release kinetics of drug-loaded APC nanoparticles were examined for various categories of drugs, including hydrophilic, hydrophobic, and protein drugs, under different pH values of the surroundings. Effects of APC nanoparticles were also evaluated in lung cancer cells and neural stem cells. The use of APC nanoparticles as a drug delivery system maintained the bioactivity of the drug to inhibit the proliferation of lung cancer cells (with ~40% reduction) and to relieve the growth inhibitory effect on neural stem cells. These findings indicate that the pH-sensitive and biocompatible composite nanoparticles of sulfated polysaccharide and chitosan well keep the antiviral and antibacterial properties and may serve as a promising multifunctional drug carrier for further biomedical applications.

Protein interactors of 3-O sulfated heparan sulfates in human MCI and age-matched control cerebrospinal fluid.

Heparan sulfates (HS) proteoglycans are commonly found on the cell surface and mediate many processes. Binding of HS ligands is determined by the sulfation code on the HS chain that can be N-/2-O/6-O- or 3-O-sulfated, generating heterogenous sulfation patterns. 3-O sulfated HS (3S-HS) play a role in several (patho)physiological processes such as blood coagulation, viral pathogenesis and binding and internalization of tau in Alzheimer's disease. However, few 3S-HS-specific interactors are known. Thus, our insight into the role of 3S-HS in health and disease is limited, especially in the central nervous system. Using human CSF, we determined the interactome of synthetic HS with defined sulfation patterns. Our affinity-enrichment mass spectrometry studies expand the repertoire of proteins that may interact with (3S-)HS. Validating our approach, ATIII, a known 3S-HS interactor, was found to require GlcA-GlcNS6S3S for binding, similar to what has been reported. Our dataset holds novel, potential HS and 3S-HS protein ligands, that can be explored in future studies focusing on molecular mechanisms that depend on 3S-HS in (patho)physiological conditions.

Atmospheric Deposition around the Industrial Areas of Milazzo and Priolo Gargallo (Sicily-Italy)-Part A: Major Ions.

The chemical composition of rainwater was studied in two highly-industrialised areas in Sicily (southern Italy), between June 2018 and July 2019. The study areas were characterised by large oil refining plants and other industrial hubs whose processes contribute to the release of large amounts of gaseous species that can affect the chemical composition of atmospheric deposition As in most of the Mediterranean area, rainwater acidity (ranging in the study area between 3.9 and 8.3) was buffered by the dissolution of abundant geogenic carbonate aerosol. In particular, calcium and magnesium cations showed the highest pH-neutralizing factor, with ~92% of the acidity brought by SO42- and NO3- neutralized by alkaline dust. The lowest pH values were observed in samples collected after abundant rain periods, characterised by a less significant dry deposition of alkaline materials. Electrical Conductivity (ranging between 7 µS cm-1 and 396 µS cm-1) was inversely correlated with the amount of rainfall measured in the two areas. Concentrations of major ionic species followed the sequence Cl- > Na+ > SO42- ≃ HCO3- > ≃ Ca2+ > NO3- > Mg2+ > K+ > F-. High loads of Na+ and Cl- (with a calculated R2 = 0.99) reflected proximity to the sea. Calcium, potassium, and non-sea-salt magnesium had a prevalent crustal origin. Non-sea salt sulphate, nitrate, and fluoride can be attributed mainly to anthropogenic sources. Mt. Etna, during eruptive periods, may be also considered, on a regional scale, a significant source for fluoride, non-sea salt sulphate, and even chloride.

Inhibitory activity of a sulfated oligo-porphyran from Pyropia yezoensis against SARS-CoV-2.

COVID-19 caused by SARS-CoV-2 has spread around the world at an unprecedented rate. A more homogeneous oligo-porphyran with mean molecular weight of 2.1 kD, named OP145, was separated from Pyropia yezoensis. NMR analysis showed OP145 was mainly composed of →3)-ß-d-Gal-(1 â†’ 4)-α-l-Gal (6S) repeating units with few replacement of 3,6-anhydride, and the molar ratio was 1:0.85:0.11. MALDI-TOF MS revealed OP145 contained mainly tetrasulfate-oligogalactan with Dp range from 4 to 10 and with no more than two 3,6-anhydro-α-l-Gal replacement. The inhibitory activity of OP145 against SARS-CoV-2 was investigated in vitro and in silico. OP145 could bind to Spike glycoprotein (S-protein) through SPR result, and pseudovirus tests confirmed that OP145 could inhibite the infection with an EC50 of 37.52 µg/mL. Molecular docking simulated the interaction between the main component of OP145 and S-protein. All the results indicated that OP145 had the potency to treat and prevent COVID-19.

The diverse role of heparan sulfate and other GAGs in SARS-CoV-2 infections and therapeutics.

In December 2019, the global coronavirus disease 2019 (COVID-19) pandemic began in Wuhan, China. COVID-19 is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which infects host cells primarily through the angiotensin-converting enzyme 2 (ACE2) receptor. In addition to ACE2, several studies have shown the importance of heparan sulfate (HS) on the host cell surface as a co-receptor for SARS-CoV-2-binding. This insight has driven research into antiviral therapies, aimed at inhibiting the HS co-receptor-binding, e.g., by glycosaminoglycans (GAGs), a family of sulfated polysaccharides that includes HS. Several GAGs, such as heparin (a highly sulfated analog of HS), are used to treat various health indications, including COVID-19. This review is focused on current research on the involvement of HS in SARS-CoV-2 infection, implications of viral mutations, as well as the use of GAGs and other sulfated polysaccharides as antiviral agents.

Oxidation of the nitrogen-free phosphonate antiscalants HEDP and PBTC in reverse osmosis concentrates: Reaction kinetics and degradation rate.

Reverse osmosis (RO) is an advanced technology used to produce potable water from a variety of water sources, including surface water, seawater and wastewater. The yield of the product water from the RO systems is increased by the addition of antiscalants which prevent scaling from calcium and other ions. Removal of antiscalants from RO concentrate can induce the precipitation of oversaturated scale-forming substances, enable additional water recovery from RO concentrates, and reduce the risk of eutrophication after concentrate disposal into the receiving water (e.g., river water). This study aims to provide a better insight into oxidation reactions of the N-free phosphonate antiscalants 1-hydroxyethane-1,1-diphosphonic acid (HEDP) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) with ozone, hydroxyl radical (•OH) and sulfate radicals (SO4•-). Ozone barely reacts with HEDP and PBTC at pH 7 (k < 10 M-1s - 1), while second order reaction rates of SO4•- and •OH were determined to be in the range 107-108M - 1s - 1. Sulfate, silicate and chloride matrices increased HEDP ozone degradation rate possibly due to metal complexation effect. Whereas carbonate and chloride hindered PBTC ozone degradation, and natural organic matter (NOM) inhibited both HEDP and PBTC degradation through scavenging of •OH. The SO4•-- radical based oxidation process of HEDP and PBTC is mainly inhibited by carbonate and NOM, interestingly only HEDP degradation is inhibited by chloride whereby the PBTC could not be fully degraded (degradation < 60%). The oxidation of PBTC is in real RO concentrates in both processes limited to 10% degradation, whereas HEDP could be degraded up to 60% with ozone and UV/persulfate application.

Remediation of Acid Mine Drainage (AMD) Using Steel Slag: Mechanism of the Alkalinity Decayed Process.

Steel slag has been proven to be an effective environment remediation media for acid neutralization, and a potential aid to mitigate acid mine drainage (AMD). Yet its acid neutralization capacity (ANC) is frequently inhibited by precipitate after a period of time, while the characteristics of the precipitate formation process are unclear yet. In this study, ANC for basic oxygen steel slag was conducted by neutralization experiments with dilute sulfuric acid (0.1 M) and real AMD. Some partially neutralized steel slag samples were determined by X-ray diffraction (XRD), scanning electron microscopy combined with an energy dispersive spectrometer (SEM-EDS), and N2 adsorption tests to investigate the potential formation process of the precipitate. The results indicated that Ca-bearing constitutes leaching and sulfate formation were two main reactions throughout the neutralization process. A prominent transition turning point from leaching to precipitate was at about 40% of the neutralization process. Tricalcium silicate (Ca3SiO5) played a dominant role in the alkalinity-releasing stage among Ca-bearing components, while the new-formed well crystalline CaSO4 changed the microstructure of steel slag and further hindered alkaline components releasing. For steel slag of 200 mesh size, the ANC value for the steel slag sample was 8.23 mmol H+/g when dilute sulfate acid was used. Neutralization experiments conducted by real AMD confirmed that the steel slag ANC was also influenced by the high contaminants, such as Fe2+, due to the hydroxides precipitate reactions except for sulfate formation reactions.

Partial characterization and anticoagulant activity of sulfated galactan from the green seaweed Halimeda opuntia.

The number of deaths associated with cardiovascular diseases (CVD) increases every year, leading to an intense search for new compounds that may be employed as anticoagulants. One of the classes of bioprospected molecules comprises sulfated polysaccharides (SP) from seaweed, as heparin displays many adverse effects associated with its use. The present study aimed to characterize and evaluate the anticoagulant potential of SP extracted from the green algae Halimeda opuntia. Four PS-rich fractions, F23, F44, F60 and F75, were obtained by proteolytic digestion in papain followed by ethanol precipitation. The presence of SP was confirmed by agarose gel electrophoresis, revealing different populations in each fraction. The F44 fraction is noteworthy compared to the other fractions, presenting a 5% yield compared to the initial algae weight and anticoagulant activity revealed by the activated partial thromboplastin time (APTT) assay (intrinsic/common coagulation pathway). Surprisingly, F44 purification (SP peak P1F44) resulted in prothrombin time (PT) activity (extrinsic coagulation pathway) at a 160 µg/mL, in addition to enhanced APTT activity. The P1F44 anticoagulant activity mechanism was shown to be dependent on two coagulations factors, IIa and Xa, more potent via IIa. Future assessments will be performed to assess this fraction in the medical clinic.

Chilensosides E, F, and G-New Tetrasulfated Triterpene Glycosides from the Sea Cucumber Paracaudina chilensis (Caudinidae, Molpadida): Structures, Activity, and Biogenesis.

Three new tetrasulfated triterpene glycosides, chilensosides E (1), F (2), and G (3), have been isolated from the Far-Eastern sea cucumber Paracaudina chilensis (Caudinidae, Molpadida). The structures were established based on extensive analysis of 1D and 2D NMR spectra and confirmed by HR-ESI-MS data. The compounds differ in their carbohydrate chains, namely in the number of monosaccharide residues (five or six) and in the positions of sulfate groups. Chilensosides E (1) and F (2) are tetrasulfated pentaosides with the position of one of the sulfate groups at C-3 Glc3, and chilensoside G (3) is a tetrasulfated hexaoside. The biogenetic analysis of the glycosides of P. chilensis has revealed that the structures form a network due to the attachment of sulfate groups to almost all possible positions. The upper semi-chain is sulfated earlier in the biosynthetic process than the lower one. Noticeably, the presence of a sulfate group at C-3 Glc3-a terminal monosaccharide residue in the bottom semi-chain of compounds 1 and 2-excludes the possibility of this sugar chain's further elongation. Presumably, the processes of glycosylation and sulfation are concurrent biosynthetic stages. They can be shifted in time in relation to each other, which is a characteristic feature of the mosaic type of biosynthesis. The hemolytic action of compounds 1-3 against human erythrocytes and cytotoxic activities against five human cancer cell lines were tested. The compounds showed moderate hemolytic activity but were inactive against cancer cells, probably because of their structural peculiarities, such as the combination of positions of four sulfate groups.

Fucoidan from Fucus vesiculosus: Evaluation of the Impact of the Sulphate Content on Nanoparticle Production and Cell Toxicity.

The composition of seaweeds is complex, with vitamins, phenolic compounds, minerals, and polysaccharides being some of the factions comprising their structure. The main polysaccharide in brown seaweeds is fucoidan, and several biological activities have been associated with its structure. Chitosan is another marine biopolymer that is very popular in the biomedical field, owing to its suitable features for formulating drug delivery systems and, particularly, particulate systems. In this work, the ability of fucoidan to produce nanoparticles was evaluated, testing different amounts of a polymer and using chitosan as a counterion. Nanoparticles of 200-300 nm were obtained when fucoidan prevailed in the formulation, which also resulted in negatively charged nanoparticles. Adjusting the pH of the reaction media to 4 did not affect the physicochemical characteristics of the nanoparticles. The IC50 of fucoidan was determined, in both HCT-116 and A549 cells, to be around 160 µg/mL, whereas it raised to 675-100 µg/mL when nanoparticles (fucoidan/chitosan = 2/1, w/w) were tested. These marine materials (fucoidan and chitosan) provided features suitable to formulate polymeric nanoparticles to use in biomedical applications.

Reactive oxygen species affect the potential for mineralization processes in permeable intertidal flats.

Intertidal permeable sediments are crucial sites of organic matter remineralization. These sediments likely have a large capacity to produce reactive oxygen species (ROS) because of shifting oxic-anoxic interfaces and intense iron-sulfur cycling. Here, we show that high concentrations of the ROS hydrogen peroxide are present in intertidal sediments using microsensors, and chemiluminescent analysis on extracted porewater. We furthermore investigate the effect of ROS on potential rates of microbial degradation processes in intertidal surface sediments after transient oxygenation, using slurries that transitioned from oxic to anoxic conditions. Enzymatic removal of ROS strongly increases rates of aerobic respiration, sulfate reduction and hydrogen accumulation. We conclude that ROS are formed in sediments, and subsequently moderate microbial mineralization process rates. Although sulfate reduction is completely inhibited in the oxic period, it resumes immediately upon anoxia. This study demonstrates the strong effects of ROS and transient oxygenation on the biogeochemistry of intertidal sediments.

Molecular Dynamics-Based Comparative Analysis of Chondroitin and Dermatan Sulfates.

Glycosaminoglycans (GAGs) are a class of linear anionic periodic polysaccharides containing disaccharide repetitive units. These molecules interact with a variety of proteins in the extracellular matrix and so participate in biochemically crucial processes such as cell signalling affecting tissue regeneration as well as the onset of cancer, Alzheimer's or Parkinson's diseases. Due to their flexibility, periodicity and chemical heterogeneity, often termed "sulfation code", GAGs are challenging molecules both for experiments and computation. One of the key questions in the GAG research is the specificity of their intermolecular interactions. In this study, we make a step forward to deciphering the "sulfation code" of chondroitin sulfates-4,6 (CS4, CS6, where the numbers correspond to the position of sulfation in NAcGal residue) and dermatan sulfate (DS), which is different from CSs by the presence of IdoA acid instead of GlcA. We rigorously investigate two sets of these GAGs in dimeric, tetrameric and hexameric forms with molecular dynamics-based descriptors. Our data clearly suggest that CS4, CS6 and DS are substantially different in terms of their structural, conformational and dynamic properties, which contributes to the understanding of how these molecules can be different when they bind proteins, which could have practical implications for the GAG-based drug design strategies in the regenerative medicine.

Evolutionary ecology of microbial populations inhabiting deep sea sediments associated with cold seeps.

Deep sea cold seep sediments host abundant and diverse microbial populations that significantly influence biogeochemical cycles. While numerous studies have revealed their community structure and functional capabilities, little is known about genetic heterogeneity within species. Here, we examine intraspecies diversity patterns of 39 abundant species identified in sediment layers down to 430 cm below the sea floor across six cold seep sites. These populations are grouped as aerobic methane-oxidizing bacteria, anaerobic methanotrophic archaea and sulfate-reducing bacteria. Different evolutionary trajectories are observed at the genomic level among these physiologically and phylogenetically diverse populations, with generally low rates of homologous recombination and strong purifying selection. Functional genes related to methane (pmoA and mcrA) and sulfate (dsrA) metabolisms are under strong purifying selection in most species investigated. These genes differ in evolutionary trajectories across phylogenetic clades but are functionally conserved across sites. Intrapopulation diversification of genomes and their mcrA and dsrA genes is depth-dependent and subject to different selection pressure throughout the sediment column redox zones at different sites. These results highlight the interplay between ecological processes and the evolution of key bacteria and archaea in deep sea cold seep extreme environments, shedding light on microbial adaptation in the subseafloor biosphere.

Four decades of regional wet deposition, local bulk deposition, and stream-water chemistry show the influence of nearby land use on forested streams in Central Appalachia.

Hydrologic monitoring began on two headwater streams (<1 km2) on the University of Kentucky's Robinson Forest in 1971. We evaluated stream-water (1974-2013) and bulk-deposition (wet + dust) (1984-2013) chemistry in the context of regional wet-deposition patterns that showed decreases in both sulfate and nitrate concentrations as well as proximal surface-mine expansion. Decadal time steps (1974-83, 1984-93, 1994-2003, 2004-2013) were used to quantify change. Comparison of the first two decades showed similarly decreased sulfate (minimum flow-adjusted annual-mean concentration of ≈13.5 mg/L in 1982 to 8.8 mg/L in 1992) and increased pH (6.6-6.8) in both streams, reflecting contemporaneous changes in both bulk and wet deposition. In contrast, concentrations of nitrate (0.14 to >0.25 mg/L) and base cations increased between these two decades, coinciding with expansion of surface mining between 1985 and 1995. In 2004, stream-water pH (6.7 in 2004), sulfate (9.2 mg/L), and nitrate (>0.11 mg/L) were similar to 1982, despite wet-deposition concentrations being lower. Base-cation concentrations were higher in the stream adjacent to ongoing surface mining relative to the stream situated near the middle of the experimental forest. However, pH decreased to approximately 5.7 by 2013 for both streams, which, combined with a shift in dominant cations from calcium to magnesium and potassium, indicates that the soil-buffering capacity of this landscape has been exceeded. Ratios of bulk deposition and stream-water concentrations indicate enrichment of sulfate (1.7-25.2) and cations (0.5-64.8), but not nitrogen (0.1-5.6), indicating that the Forest is not nitrogen saturated and that ongoing changes in water-quality are sulfate driven. When concentrations were adjusted to account for changes in streamflow (climate) over the 4 decades, external influences (land management/regulation) explained most change. The amount and direction of change differed among constituents, both between consecutive decades and between the first and last decades, reflecting the influence of localized surface mining even as regional wet deposition continued to improve due to the Clean Air Act. The implication is that localized stressors have the potential to out-pace the benefits of national environmental policies for communities that depend on local water-resources in similar environments.

A novel autotrophic denitrification and nitrification integrated constructed wetland process for marine aquaculture wastewater treatment.

We undertook a lab-scale evaluation of a novel autotrophic denitrification and nitrification integrated constructed wetland (ADNI-CW) for improved carbon (C), nitrogen (N), and sulfur (S) cycling to treat mariculture wastewater. The process involved an up-flow autotrophic denitrification constructed wetland unit (AD-CW) for sulfate reduction and autotrophic denitrification, and an autotrophic nitrification constructed wetland unit (AN-CW) for nitrification. The 400-day experiment investigated the performance of the AD-CW, AN-CW, and entire ADNI-CW processes under various hydraulic retention times (HRTs), nitrate concentrations, dissolved oxygen levels, and recirculation ratios. Under various HRTs, the AN-CW achieved a nitrification performance exceeding 92%. Correlation analysis of the chemical oxygen demand (COD) revealed that, on average, approximately 96% of COD was removed by sulfate reduction. Under different HRTs, increases in influent NO3--N concentrations caused the amount of sulfide to gradually decrease from sufficient to deficient, and the autotrophic denitrification rate also decreased from 62.18 to 40.93%. In addition, when the NO3--N load rate was above 21.53 g N/m2·d, the transformation of organic N by mangrove roots may have increased NO3--N in the top effluent of the AD-CW. The coupling of N and S metabolic processes mediated by various functional microorganisms (Proteobacteria, Chloroflexi, Actinobacteria, Bacteroidetes, and unclassified_d__Bacteria) enhanced N removal. We intensively explored the effects of changing inputs as culture species developed on the physical, chemical, and microbial changes of CW to ensure a consistent and effective management of C, N, and S. This study lays the foundation for green and sustainable mariculture development.

Study on Synthesizing Isobornyl Acetate/Isoborneol from Camphene Using α-Hydroxyl Carboxylic Acid Composite Catalyst.

This study examined the preparation of isobornyl acetate/isoborneol from camphene using an α-hydroxyl carboxylic acid (HCA) composite catalyst. Through the study of the influencing factors, it was found that HCA and boric acid exhibited significant synergistic catalysis. Under optimal conditions, when tartaric acid-boric acid was used as the catalyst, the conversion of camphene and the gas chromatography (GC) content and selectivity of isobornyl acetate were 92.9%, 88.5%, and 95.3%, respectively. With the increase in the ratio of water to acetic acid, the GC content and selectivity of isobornol in the product increased, but the conversion of camphene decreased. The yield of isobornol was increased by adding ethyl acetate or titanium sulfate/zirconium sulfate to form a ternary composite catalyst. When a ternary complex of titanium sulfate, tartaric acid, and boric acid was used as the catalyst, the GC content of isobornol in the product reached 55.6%. Under solvent-free conditions, mandelic acid-boric acid could catalyze the hydration reaction of camphene, the GC content of isoborneol in the product reached 26.1%, and the selectivity of isoborneol was 55.9%. The HCA-boric acid composite catalyst can use aqueous acetic acid as a raw material, which is also beneficial for the reuse of the catalyst.

Microbial sensitivity to temperature and sulfate deposition modulates greenhouse gas emissions from peat soils.

Peatlands are among the largest natural sources of atmospheric methane (CH4 ) worldwide. Microbial processes play a key role in regulating CH4 emissions from peatland ecosystems, yet the complex interplay between soil substrates and microbial communities in controlling CH4 emissions as a function of global change remains unclear. Herein, we performed an integrated analysis of multi-omics data sets to provide a comprehensive understanding of the molecular processes driving changes in greenhouse gas (GHG) emissions in peatland ecosystems with increasing temperature and sulfate deposition in a laboratory incubation study. We sought to first investigate how increasing temperatures (4, 21, and 35°C) impact soil microbiome-metabolome interactions; then explore the competition between methanogens and sulfate-reducing bacteria (SRBs) with increasing sulfate concentrations at the optimum temperature for methanogenesis. Our results revealed that peat soil organic matter degradation, mediated by biotic and potentially abiotic processes, is the main driver of the increase in CO2 production with temperature. In contrast, the decrease in CH4 production at 35°C was linked to the absence of syntrophic communities and the potential inhibitory effect of phenols on methanogens. Elevated temperatures further induced the microbial communities to develop high growth yield and stress tolerator trait-based strategies leading to a shift in their composition and function. On the other hand, SRBs were able to outcompete methanogens in the presence of non-limiting sulfate concentrations at 21°C, thereby reducing CH4 emissions. At higher sulfate concentrations, however, the prevalence of communities capable of producing sufficient low-molecular-weight carbon substrates for the coexistence of SRBs and methanogens was translated into elevated CH4 emissions. The use of omics in this study enhanced our understanding of the structure and interactions among microbes with the abiotic components of the system that can be useful for mitigating GHG emissions from peatland ecosystems in the face of global change.