High Yield Research Articles

Transforming waste into valuables: Preparation and evaluation of dual-ligand hydrophobic charge-induction chromatography using two poor performing ligands

In conventional chromatographic ligand screening, underperforming ligands are often dismissed. However, this practice may inadvertently overlook potential opportunities. This study aims to investigate whether these underperforming ligands can be repurposed as valuable assets. Hydrophobic charge-induction chromatography (HCIC) is chosen as the validation target for its potential as an innovative chromatographic mode. A novel dual-ligand approach is employed, combining two suboptimal ligands (5-Aminobenzimidazole and Tryptamine) to explore enhanced performance and optimization prospects. Various dual-ligand HCIC resins with different ligand densities were synthesized by adjusting the ligand ratio and concentration. The resins were characterized to assess appearance, functional groups, and pore features using SEM, FTIR, and ISEC techniques. Performance assessments were conducted using single-ligand mode resins as controls, evaluating the selectivity against human immunoglobulin G and human serum albumin. Static adsorption experiments were performed to understand pH and salt influence on adsorption. Breakthrough experiments were conducted to assess dynamic adsorption capacity of the novel resin. Finally, chromatographic separation using human serum was performed to evaluate the purity and yield of the resin. Results indicated that the dual-ligand HCIC resin designed for human antibodies demonstrates exceptional selectivity, surpassing not only single ligand states but also outperforming certain high-performing ligand types, particularly under specific salt and pH conditions. Ultimately, a high yield of 83.9 % and purity of 96.7 % were achieved in the separation of hIgG from human serum with the dual-ligand HCIC, significantly superior to the single-ligand resins. In conclusion, through rational design and proper operational conditions, the dual-ligand mode can revitalize underutilized ligands, potentially introducing novel and promising chromatographic modes.

N-doped carbon nanotube arrays Encapsuled with cobalt‑nickel alloy as superior free-standing electrodes for ultrahigh-rate hydrogen peroxide production

Electrocatalytic oxygen reduction via the two-electron pathway (2e−-ORR) is an environmentally friendly and promising route for hydrogen peroxide (H2O2) production. Carbon-based catalysts with transition metal species have been widely investigated due to their high tunability. However, the H2O2 production performance of such catalysts is still far from the requirement of practical applications, owing to their contradiction between durability and ORR activity/selectivity. In this work, metal alloy is encapsulated within the free-standing N-doped carbon nanotube arrays, named NiCo-CNTs-x (x represents the duration of the cation substitution process in hours), to precisely regulate the activity and selectivity of nitrogen sites on the surface of the carbon layer, meanwhile hindering the dissolution of alloy inside the CNTs, thus realizing long-term stability and high-activity catalysis for 2e−-ORR. Therefore, the NiCo-CNTs-30 demonstrates high activity (onset potential around 0.7 V) and selectivity (greater than 85% within the range of 0–0.8 V), and delivers a high yield of 11.7 mg L−1 h−1 with no current decay or structural damage within 24 h, showcasing its exceptional long-term stability. The catalyst can also effectively degrade organic dyes, making it highly promising for industrial applications.

Biofortification of wheat in salt-affected soil through seed priming and soil application of zinc

ContextGiven the global significance of wheat production and consumption, it is imperative to achieve high yields of nutritious wheat grains. However, the inadequate availability of zinc (Zn) in salt-affected soils can aggravate salt stress, decrease wheat grain yield, and grain Zn concentration. This study compared the effectiveness of soil Zn application and seed Zn priming in increasing Zn biofortification and grain yield of Zn-biofortified wheat grown in alkaline-calcareous soil affected by salts. MethodsEighteen pots were filled with alkaline-calcareous soil containing elevated levels of soluble salts and exchangeable sodium (Na). The pots were subjected to soil Zn application (0 or 8 mg kg−1) and seed priming (control/non-, hydro-, or Zn-primed seeds) treatments, applied to a Zn-biofortified wheat (cv. Zincol-2016). Plant samples were collected at the heading and maturity stages to measure parameters related to plant growth and grain quality. FindingsSoil Zn application increased grain and straw yields across seed priming treatments by a maximum of 23 %, and seed Zn priming increased grain and straw yields across soil Zn rates by a maximum of 21 %. This yield response was accompanied by significant increases in grain potassium and Zn concentrations at maturity, as well as non-significant to significant increases in photosynthetic parameters (stomatal conductance, photosynthetic rate and transpiration rate) in flag leaves during heading. Additionally, compared to control, the combined treatment of soil Zn application and seed Zn priming decreased grain Na concentration by 14 %. Compared to control, both soil Zn application and seed Zn priming significantly increased grain Zn concentration. With the combined application treatment, the grain Zn concentration reached 27 mg kg−1, but it remained significantly below the desired level of >37 mg kg−1. Seed Zn priming decreased the phytate-to-Zn molar ratio in grains, while the treatments that received soil Zn application exhibited the lowest values of this ratio, potentially increasing Zn bioavailability to humans. ConclusionsThe findings suggest that soil Zn application is more effective in enhancing grain yield and Zn concentration, while seed Zn priming remains crucial in low-Zn and high-salt soils. Future research should optimize Zn application strategies for Zn-biofortified wheat cultivated in salt-affected fields.

4-Hydroxybenzoic Acid-Based Hydrazide–Hydrazones as Potent Growth Inhibition Agents of Laccase-Producing Phytopathogenic Fungi That Are Useful in the Protection of Oilseed Crops

The research on new compounds against plant pathogens is still socially and economically important. It results from the increasing resistance of pests to plant protection products and the need to maintain high yields of crops, particularly oilseed crops used to manufacture edible and industrial oils and biofuels. We tested thirty-five semi-synthetic hydrazide–hydrazones with aromatic fragments of natural origin against phytopathogenic laccase-producing fungi such as Botrytis cinerea, Sclerotinia sclerotiorum, and Cerrena unicolor. Among the investigated molecules previously identified as potent laccase inhibitors were also strong antifungal agents against the fungal species tested. The highest antifungal activity showed derivatives of 4-hydroxybenzoic acid and salicylic aldehydes with 3-tert-butyl, phenyl, or isopropyl substituents. S. sclerotiorum appeared to be the most susceptible to the tested compounds, with the lowest IC50 values between 0.5 and 1.8 µg/mL. We applied two variants of phytotoxicity tests for representative crop seeds and selected hydrazide–hydrazones. Most tested molecules show no or low phytotoxic effect for flax and sunflower seeds. Moreover, a positive impact on seed germination infected with fungi was observed. With the potential for application, the cytotoxicity of the hydrazide–hydrazones of choice toward MCF-10A and BALB/3T3 cell lines was lower than that of the azoxystrobin fungicide tested.

Enhancing root physiology for increased yield in water-saving and drought-resistance rice with optimal irrigation and nitrogen

ObjectivesWater-saving and drought-resistance rice (WDR) plays a vital role in the sustainable development of agriculture. Nevertheless, the impacts and processes of water and nitrogen on grain yield in WDR remain unclear.MethodsIn this study, Hanyou 73 (WDR) and Hyou 518 (rice) were used as materials. Three kinds of nitrogen fertilizer application rate (NFAR) were set in the pot experiment, including no NFAR (nitrogen as urea applied at 0 g/pot), medium NFAR (nitrogen as urea applied at 15.6 g/pot), and high NFAR (nitrogen as urea applied at 31.2 g/pot). Two irrigation regimes, continuous flooding cultivation and water stress, were set under each NFAR. The relationships between root and shoot morphophysiology and grain yield in WDR were explored.ResultsThe results demonstrated the following: 1) under the same irrigation regime, the grain yield of two varieties increased with the increase of NFAR. Under the same NFAR, the reduction of irrigation amount significantly reduced the grain yield in Hyou 518 (7.1%–15.1%) but had no substantial influence on the grain yield in Hanyou 73. 2) Under the same irrigation regime, increasing the NFAR could improve the root morphophysiology (root dry weight, root oxidation activity, root bleeding rate, root total absorbing surface area, root active absorbing surface area, and zeatin + zeatin riboside contents in roots) and aboveground physiological indexes (leaf photosynthetic rate, non-structural carbohydrate accumulation in stems, and nitrate reductase activity in leaves) in two varieties. Under the same NFAR, increasing the irrigation amount could significantly increase the above indexes in Hyou 518 (except root dry weight) but has little effect on Hanyou 73. 3) Analysis of correlations revealed that the grain yield of Hyou 518 and Hanyou 73 was basically positively correlated with aboveground physiology and root morphophysiology, respectively.ConclusionThe grain yield could be maintained by water stress under medium NFAR in WDR. The improvement of root morphophysiology is a major factor for high yield under the irrigation regime and NFAR treatments in WDR.

Occurrence of Stem Rot on Acacia mangium Caused by Amauroderma subresinosum.

Acacia mangium has the characteristics of developed root system, nitrogen fixation and soil improvement, fast growth and high yield, and improvement of soil fertility. It is often used as a windbreak tree species in rubber plantations, a highway shade tree, for coastal and mountain restoration in Hainan . In October 2021, a stem rot disease with an incidence of 3% was found in Baisha city(19°22'18″N,109°16'58″E), Hainan Province, China. In the early stage of the disease, the crown showed chlorotic leaves, followed by defoliation. In later stages, whole tree dieback was observed. The basal tissue of the stem of the diseased tree had white rot, and black-brown basidiocarps were observed about 1 m away from the ground. The basidiocarps surface of fresh was disinfected with 75 % ethanol, the epidermal tissue was removed, and the inner tissue blocks were transferred to PDA medium. After culturing in dark at 28°C for 3 days, a colony with white aerial mycelium was isolated and designated: HNBSMZXS20211011001. The basidiocarp was dark brown, sessile, mostly one-year-old, and the cap is nearly semi-circular, wooden, slightly shiny, with a size of 14.7 to 18.1cm × 9.5 to 10.1 cm. The base is thick (5 to 6.5 cm) and the edge is thin (0.3 to 0.7 cm). The basidiospores are oval, 10.7 to 13.65μm × 6.7 to 9.06μm in size, with a double-layer wall. The outer wall is transparent and the inner wall is light yellow. The basidiospores contain 1~2 oil droplets. The morphological features are consistent with those of Amauroderma subresinosum (Murrill) Corner (Zhang et al., 2000). The basidiocarps and type strain cultures were stored as accessions in the Laboratory of Plant Pathogen Fungus Biology, Hainan University. For pathogenicity tests, sawdust culture medium was used (soft sawdust 82%, wheat bran 15%, glucose 2%, gypsum 1%, mixed with water in proportion, sterilized at 121°C for 40min). The mycelium plug from a fresh culture (d=5mm) was taken from the edge of the colony of type strain, and transferred to the sterilized sawdust medium. When mycelium has colonized the media, it was used to inoculate plants. Media without mycelium was used as a control. Naturally growing seedlings (three year old) of A.mangium were selected from the teaching nurseries of Hainan University (20°6'25''N,110°32'24''E). First, 75 % alcohol was sprayed on the stem of the base of A.mangium for surface disinfection. After the surface was dried, a slight wound (about 4×2cm) was made on the surface with a sterilized scalpel. A inoculated and control sawdust media rods were tightly attached to the wound, moistened with cotton balls soaked in sterile water, and then fixed with plastic wrap, and the outer layer was wrapped with newsprint. Inoculation and controls were replicated three times. Two months after inoculated, the stems of the plants inoculated with the isolated fungus grew white hyphae and showed white rot symptoms, and the leaves became chlorotic and defoliated with complete tree decline in six months, which was consistent with the original symptoms observed. By comparison, white callus had grown on the edge of the stem wounds of the control plants. The same fungus was re-isolated from the inoculated plants and confirmed as A.subresinosum based on the internal transcribed spacer (ITS), the ribosomal large subunit(LSU), and the translation elongation factor 1-α(EF1-α) gene sequence, the fungus was not isolated from control plants thus fulfilling Koch's postulates. The ITS region of r-DNA, the ribosomal large subunit(LSU), the translation elongation factor 1-α gene(EF1-α) were amplified using ITS1/ITS4(White et al. 1990), LR0R/LR5(Hu et al. 2021), EF1-983F/EF1-1567R(Buckley et al. 2005) primers, respectively. The sequences of ITS (OQ674500), LSU (OQ674502) and EF1-α gene (OQ883944) were submitted to GenBank. Through with BLAST, the identities of the ITS, LSU and EF1-α sequences to A.subresinosum (GenBank Accession no. ITS: LC176755; LSU: MK119903 and EF1-α: MK121572) was 99.82%; 99.15% and 99.82%, respectively, the identities were more than 99 %. It was reported that A.subresinosum could infect Casuarina equisetifolia and Areca catechu(Chen et al., 2016; Cheng. 2017; Wu et al., 2019). However, this is the first report of Amauroderma subresinosum causing stem rot of Acacia mangiumin Hainan, China. This report will facilitate field diagnosis and provide scientific reference for further research on the disease.

Synthesis, In Silico Study, and In Vitro Antifungal Activity of New 5-(1,3-Diphenyl-1H-Pyrazol-4-yl)-4-Tosyl-4,5-Dihydrooxazoles

The increase in multi-drug resistant Candida strains has caused a sharp rise in life-threatening fungal infections in immunosuppressed patients, including those with SARS-CoV-2. Novel antifungal drugs are needed to combat multi-drug-resistant yeasts. This study aimed to synthesize a new series of 2-oxazolines and evaluate the ligands in vitro for the inhibition of six Candida species and in silico for affinity to the CYP51 enzymes (obtained with molecular modeling and protein homology) of the same species. The 5-(1,3-diphenyl-1H-pyrazol-4-yl)-4-tosyl-4,5-dihydrooxazoles 6a-j were synthesized using the Van Leusen reaction between 1,3-diphenyl-4-formylpyrazoles 4a-j and TosMIC 5 in the presence of K2CO3 or KOH without heating, resulting in short reaction times, high compound purity, and high yields. The docking studies revealed good affinity for the active site of the CYP51 enzymes of the Candida species in the following order: 6a-j > 4a-j > fluconazole (the reference drug). The in vitro testing of the compounds against the Candida species showed lower MIC values for 6a-j than 4a-j, and for 4a-j than fluconazole, thus correlating well with the in silico findings. According to growth rescue assays, 6a-j and 4a-j (like fluconazole) inhibit ergosterol synthesis. The in silico toxicity assessment evidenced the safety of compounds 6a-j, which merit further research as possible antifungal drugs.

Use of modelling tools to assess climate change impacts on smallholder oil seed yields in South Africa.

Oil seed crops are the second most important field crops after cereals in the agricultural economy globally. The use and demand for oilseed crops such as groundnut, soybean and sunflower have grown significantly, but climate change is expected to alter the agroecological conditions required for oilseed crop production. This study aims to present an approach that utilizes decision-making tools to assess the potential climate change impacts on groundnut, soybean and sunflower yields and the greenhouse gas emissions from the management of the crops. The Decision Support Tool for Agrotechnology Transfer (DSSAT v4.7), a dynamic crop model and the Cool Farm Tool, a GHG calculator, was used to simulate yields and estimate GHG emissions from these crops, respectively. Four representative concentration pathways (RCPs 2.6, 4.5, 6.0, and 8.5), three nitrogen (0, 75, and 150 kg/ha) and phosphorous (0, 30 and 60 P kg/ha) fertilizer rates at three sites in Limpopo, South Africa (Ofcolaco, Syferkuil and Punda Maria) were used in field trials for calibrating the models. The highest yield was achieved by sunflower across all crops, years and sites. Soybean yield is projected to decrease across all sites and scenarios by 2030 and 2050, except at Ofcolaco, where yield increases of at least 15.6% is projected under the RCP 4.5 scenario. Positive climate change impacts are predicted for groundnut at Ofcolaco and Syferkuil by 2030 and 2050, while negative impacts with losses of up to 50% are projected under RCP8.5 by 2050 at Punda Maria. Sunflower yield is projected to decrease across all sites and scenarios by 2030 and 2050. A comparison of the climate change impacts across sites shows that groundnut yield is projected to increase under climate change while notable yield losses are projected for sunflower and soybean. GHG emissions from the management of each crop showed that sunflower and groundnut production had the highest and lowest emissions across all sites respectively. With positive climate change impacts, a reduction of GHG emissions per ton per hectare was projected for groundnuts at Ofcolaco and Syferkuil and for sunflower in Ofcolaco in the future. However, the carbon footprint from groundnut is expected to increase by 40 to 107% in Punda Maria for the period up to 2030 and between 70-250% for 2050, with sunflower following a similar trend. We conclude that climate change will potentially reduce yield for oilseed crops while management will increase emissions. Therefore, in designing adaptation measures, there is a need to consider emission effects to gain a holistic understanding of how both climate change impacts on crops and mitigation efforts could be targeted.

Synthesis, characterization, and optical studies of lead-free perovskite, Cs3M2Br9 (M = Bi, Sb) nanocrystals

In recent years, there has been a surge in research interest surrounding all inorganic lead perovskite nanocrystals (NCs) owing to their exceptional performance in various optoelectronic devices. Nevertheless, the presence of lead and concerns regarding its toxicity and stability have cast a shadow over their potential wide-ranging applications. In this study, we present the synthesis of two lead-free all-inorganic perovskite materials, Cs3M2Br9 (where M = Bi or Sb), in bulk form, using an aqueous halide acid medium. Additionally, we describe a top-down approach for the fabrication of two lead-free all-inorganic perovskite, Cs3M2Br9 (M = Bi or Sb) NCs. The Cs3Sb2Br9 NCs display a sheet-like morphology, while Cs3Bi2Br9 NCs exhibit a cubic structure. The PL spectra of Cs3Sb2Br9 and Cs3Bi2Br9 NCs exhibit distinct emission peaks at 476 nm and 472 nm, respectively, with relatively narrow full width at half maximum (FWHM) of 44 nm and 38 nm, respectively. Cs3Sb2Br9 and Cs3Bi2Br9 NCs demonstrate excellent thermal stability up to 320 °C and 470 °C, respectively. Notably, the high photoluminescence quantum yield (PLQY) of these NCs, Cs3Sb2Br9 NCs (31 %) and Cs3Bi2Br9 NCs (36 %) are highly beneficial for optoelectronic applications is observed.

Emission behaviors from ZnO microwire pumped CsPbBr3 perovskite microwire.

Perovskite semiconductor materials have attracted significant attention in the fields of photovoltaics and luminescence due to their excellent photoelectric properties, such as high carrier mobility, high absorption coefficient, and high fluorescence quantum yield. In particular, low-dimensional metal-halide perovskite microcrystalline materials have been reported to exhibit low-dimensional lasing phenomena and laser devices due to their high gain and widely tunable bandgap. In this Letter, one-dimensional (1-D) ZnO microwires with their ultraviolet lasing emissions are utilized as an excitation source to pump CsPbBr3 microwire on hybrid ZnO-CsPbBr3 microscale structures. At higher excitation, the amplified spontaneous emission (ASE) behaviors from CsPbBr3 microwire are realized with ultralow threshold by indirect pumping from the ZnO lasing emission for the first time, to the best of our knowledge. In comparison, the ASE behaviors from the CsPbBr3 microwire directly pumped by Nd:YAG Q-switched laser and continuous wave laser are also performed at room temperature. There are also no multimode lasing behaviors observed. The paper provides a new method to achieve a low threshold on-chip microlaser by a high-quality perovskite micro-nano structure.

Responsive Organic Fluorescent Aggregates Based on Ion‐π Interactions Away from Fluorescent Conjugated Groups

Responsive organic luminescent aggregates have a wide range of application fields, but currently there is still a lack of reasonable molecular design strategies. Introducing ion‐π interactions into molecules can effectively alter their luminescent properties. However, current research typically focuses on ion localization at luminescent conjugated groups with the strong interaction forces. In this work, we introduce the flexible alkoxy chain spacers between fluorescent conjugated groups and ion‐π interaction sites, and then adjust the fluorescence performance of the molecule by changing the strength of ion‐π interactions. Bromine ion‐based molecules with strong ion‐π interactions exhibit high and stable fluorescence quantum yields in crystals and amorphous powders under the external stimuli. Hexafluorophosphate ion‐based molecules with weak ion‐π interactions have the high fluorescence quantum yield in crystals and very low fluorescence quantum yield in amorphous powders, showing variable fluorescence intensities under external stimuli. This demonstrates a new class of responsive organic luminescent solid‐state materials.

Improving the fluorescence brightness of naphthalimide and nitrobenzoxadiazole dyes with cycloalkylamine auxochromes

We have installed cycloalkylamino auxochromes on naphthalimide (5a-5e) and nitrobenzoxadiazole (6a-6e) dyes. Their photophysical characterization revealed that the cyclobutylamino auxochrome in both dyes (5b and 6b) demonstrated high quantum yield and fluorescence brightness compared to their azetidine counterparts (5 and 6) in aqueous solution. The computational studies were performed to substantiate the experimental photophysical results. Cytotoxicity assay in breast adenocarcinoma (MDA-MB-231) and non-cancerous human embryonic kidney 293 (HEK-293) cells indicated significant biocompatibility of cyclobutylamino auxochrome. Moreover, cellular imaging and photostability experiments demonstrated the practical application of cycloalkylamino auxochromes.

Responsive Organic Fluorescent Aggregates Based on Ion-π Interactions Away from Fluorescent Conjugated Groups.

Responsive organic luminescent aggregates have a wide range of application fields, but currently there is still a lack of reasonable molecular design strategies. Introducing ion-π interactions into molecules can effectively alter their luminescent properties. However, current research typically focuses on ion localization at luminescent conjugated groups with the strong interaction forces. In this work, we introduce the flexible alkoxy chain spacers between fluorescent conjugated groups and ion-π interaction sites, and then adjust the fluorescence performance of the molecule by changing the strength of ion-π interactions. Bromine ion-based molecules with strong ion-π interactions exhibit high and stable fluorescence quantum yields in crystals and amorphous powders under the external stimuli. Hexafluorophosphate ion-based molecules with weak ion-π interactions have the high fluorescence quantum yield in crystals and very low fluorescence quantum yield in amorphous powders, showing variable fluorescence intensities under external stimuli. This demonstrates a new class of responsive organic luminescent solid-state materials.

From Dopant to Host: Solution Synthesis and Light‐Emitting Applications of Organic‐Inorganic Lanthanide‐Based Metal Halides

The rich and unique energy level structure arising from 4fn inner shell configuration of trivalent lanthanide ions (Ln3+) renders them highly attractive for light‐emitting applications. Currently, research primarily focuses on Ln3+ doping in either traditional garnets or the recently developed perovskite phosphors. However, there have been few reports on stable phosphors crystallized with pure lanthanide elements. Herein, a universal solution‐based route to eight Ln3+‐based metal halides from the organic‐inorganic A4LnX7 family is described, where A+ = 4,4‐difluoropiperidinium (DFPD+), Ln3+ = Nd3+, Eu3+, Ho3+, Sm3+, Tm3+, Tb3+, Yb3+, Er3+, and X− = Cl−, Br−. Visible photoluminescence (PL) is observed from Tb3+‐, Eu3+‐, Ho3+‐, and Sm3+‐based compounds with Tb and Eu compositions exhibiting high PL quantum yields of 90–100%; Nd3+‐, Tm3+‐, Yb3+‐, and Er3+‐based crystals show fascinating near‐infrared emission. Light‐emitting diodes (LEDs) fabricated with (DFPD)4TbCl7 yield characteristic emission of Tb3+, representing the first demonstration of electroluminescence from these organic‐inorganic Ln3+‐based metal halides. Moreover, these materials exhibit distinct excitation wavelength‐dependent emission after alloying with different Ln3+ ions, making them interesting for multicolor display and multilevel information encryption applications. It is foreseen that this study will open up the way to a possible design of robust optoelectronic devices based on lanthanide metal halides.

Tillage and Straw Management Practices Influences Soil Nutrient Distribution: A Case Study from North-Eastern Romania

Tillage practices govern crop quality and quantity through soil nutrient availability and crop root systems. A deeper knowledge of the impact of conservation tillage on soil chemical characteristics (such as pH, soil organic carbon, macro and micronutrient storage and distribution) is required for both the promotion of agricultural sustainability and environmental preservation. This study assesses the changes in soil features and properties in the context of a long-field experiment with different tillage systems and straw management practices. Research findings revealed that compared with conventional tillage (CT) conservative tillage with partial straw retention (MT) and no-tillage with straw mulching (NT) substantially boosted the organic carbon (OC) (by 6–19%), total nitrogen (TN) (by 2–12%), and available potassium content (AK) (by 2–5%), in 0–30 cm soil depth. However, the stratification trend was observed for available macro and micronutrient content (Zn, Fe, Mn) in both conservative management practices. The concentration of Cu indicates a constant pattern through a 0–30 cm soil profile with a higher concentration under MT (1.41 mg kg−1) compared to NT (1.10 mg kg−1). In particular, the results failed to establish if conservation tillage can increase the total phosphorus (TP) and potassium content (TK), where only in surface 0–10 cm an increase was observed. This research also suggested that the X-ray fluorescence analysis (XRF) of total micronutrient content (Zn, Cu, Fe, Mn) is minimal or unpredictable with no substantial differences between the tillage systems and straw return management practices. These findings suggest that conservation tillage in north-eastern Romania might be optimal to maintain soil quality status and sustain high yields.

An improved expression and purification protocol enables the structural characterization of Mnt1, an antifungal target from Candida albicans

BackgroundCandida albicans is one of the most prevalent fungi causing infections in the world. Mnt1 is a mannosyltransferase that participates in both the cell wall biogenesis and biofilm growth of C. albicans. While the cell wall performs crucial functions in pathogenesis, biofilm growth is correlated with sequestration of drugs by the extracellular matrix. Therefore, antifungals targeting CaMnt1 can compromise fungal development and potentially also render Candida susceptible to drug therapy. Despite its importance, CaMnt1 has not yet been purified to high standards and its biophysical properties are lacking.ResultsWe describe a new protocol to obtain high yield of recombinant CaMnt1 in Komagataella phaffii using methanol induction. The purified protein’s identity was confirmed by MALDI-TOF/TOF mass spectroscopy. The Far-UV circular dichroism (CD) spectra demonstrate that the secondary structure of CaMnt1 is compatible with a protein formed by α-helices and β-sheets at pH 7.0. The fluorescence spectroscopy results show that the tertiary structure of CaMnt1 is pH-dependent, with a greater intensity of fluorescence emission at pH 7.0. Using our molecular modeling protocol, we depict for the first time the ternary complex of CaMnt1 bound to its two substrates, which has enabled the identification of residues involved in substrate specificity and catalytic reaction. Our results corroborate the hypothesis that Tyr209 stabilizes the formation of an oxocarbenium ion-like intermediate during nucleophilic attack of the acceptor sugar, opposing the double displacement mechanism proposed by other reports.ConclusionsThe methodology presented here can substantially improve the yield of recombinant CaMnt1 expressed in flask-grown yeasts. In addition, the structural characterization of the fungal mannosyltransferase presents novelties that can be exploited for new antifungal drug’s development.

Construction of stereogenic center beta to the N-Pyrrolidinyl moiety via diastereoselective reactions of tricyclic lactones and the synthesis of (−)-Indolizidine 195G

The Enolates of hexahydro-3,4-dioxa-8a-aza-as-indacen-2-ones can react with electrophiles in a substrate-controlled fashion to create a new stereogenic center positioned beta to the N-pyrrolidinyl moiety. Preferential diastereoselective reactions predominantly proceeded from the convex face of the enolates, yielding stereospecific alkylated or halo-substituted products with high yields and exceptional diastereoselectivities. Di-substituted compounds were obtained by the alkylation or halogenation of the enolates of the corresponding mono-substituted compounds. Total synthesis of (−)-indolizidine 195G was also accomplished. © 2024 Elsevier Science. All rights reserved.

Photoredox-Catalyzed Decarboxylative Cross-Coupling Reaction to Synthesis Unsymmetrical Diarylmethanes.

The photoredox-catalyzed decarboxylative cross-coupling reaction of aryl acetic acids and aryl nitriles has been achieved under an argon atmosphere in high yields. This method provides a fast way to obtain prevalent aryl acetic acids from an abundant natural source. A tentative radical mechanism has been proposed.

A Tape-Wrapping Strategy towards Electrochemical Fabrication of Water-Dispersible Graphene.

Graphene has achieved mass production via various preparative routes and demonstrated its uniqueness in many application fields for its intrinsically high electron mobility and thermal conductivity. However, graphene faces limitations in assembling macroscopic structures because of its hydrophobic property. Therefore, balancing high crystal quality and good aqueous dispersibility is of great importance in practical applications. Herein, we propose a tape-wrapping strategy to electrochemically fabricate water-dispersible graphene (w-Gr) with both excellent dispersibility (~4.5 mg/mL, stable over 2 months), and well-preserved crystalline structure. A large production rate (4.5 mg/min, six times faster than previous electrochemical methods), high yield (65.4% ≤5 atomic layers) and good processability are demonstrated. A mechanism investigation indicates that the rational design of anode configuration to ensure proper oxidation, deep exfoliation and unobstructed mass transfer is responsible for the high efficiency of this strategy. This simple yet efficient electrochemical method is expected to promote the scalable preparation and applications of graphene.

Development of a scalable recombinant system for cyclic beta-1,2-glucans production

BackgroundCyclic β-1,2-glucans (CβG) are bacterial cyclic homopolysaccharides with interesting biotechnological applications. These ring-shaped molecules have a hydrophilic surface that confers high solubility and a hydrophobic cavity able to include poorly soluble molecules. Several studies demonstrate that CβG and many derivatives can be applied in drug solubilization and stabilization, enantiomer separation, catalysis, synthesis of nanomaterials and even as immunomodulators, suggesting these molecules have great potential for their industrial and commercial exploitation. Nowadays, there is no method to produce CβG by chemical synthesis and bacteria that synthesize them are slow-growing or even pathogenic, which makes the scaling up of the process difficult and expensive. Therefore, scalable production and purification methods are needed to afford the demand and expand the repertoire of applications of CβG.ResultsWe present the production of CβG in specially designed E. coli strains by means of the deletion of intrinsic polysaccharide biosynthetic genes and the heterologous expression of enzymes involved in CβG synthesis, transport and succinilation. These strains produce different types of CβG: unsubstituted CβG, anionic CβG and CβG of high size. Unsubstituted CβG with a degree of polymerization of 17 to 24 glucoses were produced and secreted to the culture medium by one of the strains. Through high cell density culture (HCDC) of that strain we were able to produce 4,5 g of pure unsubstituted CβG /L in culture medium within 48 h culture.ConclusionsWe have developed a new recombinant bacterial system for the synthesis of cyclic β-1,2-glucans, expanding the use of bacteria as a platform for the production of new polysaccharides with biotechnological applications. This new approach allowed us to produce CβG in E. coli with high yields and the highest volumetric productivity reported to date. We expect this new highly scalable system facilitates CβG availability for further research and the widespread use of these promising molecules across many application fields.