Optimum Reaction Temperature Research Articles

Dual detection of Bupleurum scorzonerifolium Willd. and Bupleurum chinense DC. using proofman–LMTIA method

A new rapid dual detection method was established to distinguish Bupleurum scorzonerifolium Willd. (BS) and Bupleurum chinense DC. (BC) simultaneously using the proofreading enzyme-mediated probe cleavage coupled with ladder-shape melting temperature isothermal amplification (proofman–LMTIA). The internal transcribed spacer (ITS) sequences of BS and BC were selected as targets for designs of proofman–LMTIA primers and proofman fluorescence probes labeled with FAM or JOE. The reaction temperature optimization, repeatability and reliability assessment, specificity assessment and sensitivity assessment of the proofman–LMTIA performed for dual detection of BS and BC and its application. The results showed that the optimal reaction temperature of the proofman–LMTIA method was at 63℃, which had strongly specificity, repeatability and reliability, as well as sensitivity, and the detection was completed within 20 min with a detection sensitivity of 1 pg/μL. The proofman–LMTIA method realized dual rapid detection of BS and BC, which showed a strong practical value. The 4 kinds were BC, 1 kind was BS, and 2 kinds were counterfeit in the detection of 7 kinds of BS or BC samples from different habitats. Our study successfully established a new approach for dual rapid detection of BS and BC using the proofman–LMTIA, which will provide an effective technique or method for the authenticity detection of authentic Chinese medicinal materials and present a very important practical significance.Graphical

L-arabinose isomerase from Lactobacillus fermentum C6: Enzymatic characteristics and its recombinant Bacillus subtilis whole cells achieving a significantly increased production of D-tagatose

L-arabinose isomerase (L-AI) is a functional enzyme for the isomerizing of D-galactose to produce D-tagatose. In this study, L-AI-C6-encoding gene from the probiotic Lactobacillus fermentum C6 was cloned and expressed in Bacillus subtilis WB600 for investigating enzymatic characteristics and bioconverting D-tagatose by means of whole-cell catalysis. Results showed that the engineered B. subtilis WB600-pMA5-LAI achieved a maximum specific activity of L-AI-C6 (232.65 ± 15.54 U/mg protein) under cultivation in LB medium at 28 °C for 40 h. The recombinant L-AI-C6 was purified, and enzymatic characteristics test showed its optimum reaction temperature and pH at 60 °C and 8.0, respectively. In addition, L-AI-C6 exhibited good stability within the pH range of 5.5–9.0. By using B. subtilis WB600-pMA5-LAI cells as whole-cell catalyst, the highest D-tagatose yield reached 42.91 ± 0.28 % with D-galactose as substrate, which was 2.41 times that of L. fermentum C6 (17.79 ± 0.11 %). This suggested that the cloning and heterologous expression of L-AI-C6 was an effective strategy for improving D-tagatose conversion by whole-cell catalysis. In brief, the present study demonstrated that the reaction temperature, pH, and stability of L-AI-C6 from L. fermentum C6 meet the demands of industrial application, and the constructed B. subtilis WB600-pMA5-LAI shows promising potential for the whole-cell biotransformation of D-tagatose.

Efficient removal and reusage of acid soluble oil in waste H2SO4 of isobutane alkylation by low-temperature carbonization process

Waste H2SO4 from industrial isobutane alkylation, a hazardous thick liquid with a high concentration of acid soluble oil (ASO) impurities, poses challenges in the regeneration process. Herein, an innovative low-temperature carbonization process was proposed to convert waste H2SO4 into the regenerated concentrated H2SO4 and sulfonated activated carbon materials (SACMs) under mild reaction conditions. The optimal reaction temperature is identified at 423.15 K with the highest TOC removal of 90.57%. The high-purity regenerated H2SO4 with a concentration of 95% as a catalyst for isobutane alkylation exhibits excellent catalytic performance with 94.54 research octane number (RON) of the alkylate. SACMs, characterized as a novel porous carbon material with plentiful hydroxyl, carboxylic acid, and sulfonic acid functional groups, demonstrate an efficient catalytic activity in the dimerization of lactic acid to produce lactide with a yield of 46.95%. Hopefully, the novel recovery process provides a promising application to optimize the regeneration process of waste H2SO4 from industrial isobutane alkylation.

A Rapid, Equipment-Free Method for Detecting Avirulence Genes of Pyricularia oryzae Using a Lateral Flow Strip-Based RPA Assay.

Rice blast, caused by Pyricularia oryzae, is one of the most destructive rice diseases worldwide. Using resistant rice varieties is the most cost-effective way to control rice blast. Consequently, it is critical to monitor the distribution frequency of avirulence (Avr) genes in rice planting fields to facilitate the breeding of resistant rice varieties. In this study, we established a rapid recombinase polymerase amplification-lateral flow dipstick (RPA-LFD) detection system for the identification of AvrPik, Avr-Piz-t, and Avr-Pi9. The optimized reaction temperature and duration were 37°C and 20 min, indicating that the reaction system could be initiated by body temperature without relying on any precision instruments. Specificity analysis showed that the primer and probe combinations targeting the three Avr genes exhibited a remarkable specificity at genus-level detection. Under the optimized condition, the lower detected thresholds of AvrPik, Avr-Piz-t, and Avr-Pi9 were 10 fg/μl, 100 fg/μl, and 10 pg/μl, respectively. Notably, the detection sensitivity of the three Avr genes was much higher than that of PCR. In addition, we also successfully detected the presence of AvrPik, Avr-Piz-t, and Avr-Pi9 in the leaf and panicle blast lesions with the RPA-LFD detection system. In particular, the genomic DNA was extracted using the simpler PEG-NaOH rapid extraction method. In summary, we developed an RPA detection system for AvrPik, Avr-Pi9, and Avr-Piz-t, combined with the PEG-NaOH rapid DNA extraction method. The innovative approach achieved rapid, real-time, and accurate detection of the three Avr genes in the field, which is helpful to understand the distribution frequency of the three Avr genes in the field and provide theoretical reference for the scientific layout of resistant rice varieties.

Characterization and application of Bacillus velezensis D6 co-producing α-amylase and protease.

Research on the co-production of multiple enzymes by Bacillus velezensis as a novel species is still a topic that needs to be studied. This study aimed to investigate the fermentation characteristics of B. velezensis D6 co-producing α-amylase and protease and to explore their enzymatic properties and applications in fermentation. The maximum co-production of α-amylase and protease reached 13.13 ± 0.72 and 2106.63 ± 64.42 U mL-1, respectively, under the optimal fermented conditions (nutrients: 20.0 g L-1 urea, 20.0 g L-1 glucose, 0.7 g L-1 MnCl2; incubation conditions: initial pH 7.0, temperature 41 °C, 8% inoculation size and 30% working volume). Moreover, the genetic co-expression of α-amylase and protease increased from 0 to 24 h and then decreased after 36 h at the transcriptional level, which coincided with the growth trend of B. velezensis D6. The optimal reaction temperature of α-amylase was 55-60 °C, while that of protease was 35-40 °C. The activities of α-amylase and protease were retained by over 80% after thermal treatment (90 °C, 1 h), which indicated that two enzymes co-produced by B. velezensis D6 demonstrated excellent thermal stability. Moreover, the two enzymes were stable over a wide pH range (pH 4.0-8.0 for α-amylase; pH 4.0-9.0 for protease). Finally, the degrees of hydrolysis of corn, rice, sorghum and soybeans by α-amylase from B. velezensis D6 reached 44.95 ± 2.95%, 57.16 ± 2.75%, 52.53 ± 4.01% and 20.53 ± 2.42%, respectively, suggesting an excellent hydrolysis effect on starchy raw materials. The hydrolysis degrees of mackerel heads and soybeans by protease were 43.93 ± 2.19% and 26.38 ± 1.72%, respectively, which suggested that the protease from B. velezensis D6 preferentially hydrolyzed animal-based protein. This is a systematic study on the co-production of α-amylase and protease by B. velezensis D6, which is crucial in widening the understanding of this species co-producing multi-enzymes and in exploring its potential application. © 2024 Society of Chemical Industry.

RT-RPA Assay Combined with a Lateral Flow Strip to Detect Soybean Mosaic Virus.

Soybean (Glycine max L.) is one of the most widely planted and used legumes in the world, being used for food, animal feed products, and industrial production. The soybean mosaic virus (SMV) is the most prevalent virus infecting soybean plants. This study developed a diagnostic method for the rapid and sensitive detection of SMV using a reverse transcription-recombinase polymerase amplification (RT-RPA) technique combined with a lateral flow strip (LFS). The RT-RPA and RT-RPA-LFS conditions to detect the SMV were optimized using the selected primer set that amplified part of the VPg protein gene. The optimized reaction temperature for the RT-RPA primer and RT-RPA-LFS primer used in this study was 38℃ for both, and the minimum reaction time was 10 min and 5 min, respectively. The RT-RPA-LFS was as sensitive as RT-PCR to detect SMV with 10 pg/μl of total RNA. The reliability of the developed RT-RPA-LFS assay was evaluated using leaves collected from soybean fields. The RT-RPA-LFS diagnostic method developed in this study will be useful as a diagnostic method that can quickly and precisely detect SMV in the epidemiological investigation of SMV, in the selection process of SMV-resistant varieties, on local farms with limited resources.

Temperature-assisted crystallization and morphology for CH3NH3PbI3 perovskite solar cells using laser-induced heat treatment

In this study, perovskite solar cells (PSCs) were fabricated using a two-step solution deposition method. A laser beam was applied at the interface between lead iodide (PbI2) and methylammonium iodide to change the reaction temperature and stimulate the growth of perovskite crystals. A notable enhancement was observed in the power conversion efficiency of PSCs. The laser scanning speed was investigated to control the reaction temperature and further control the crystallization and morphology of the perovskite film. Based on the optimized laser scanning speed, the best and average PCEs obtained were 14.33 % and 13.92 ± 0.52 %, respectively, which were higher than those achieved using the conventional technique (12.18 % and 11.37 ± 0.74 %, respectively) and the conventional heating methods (14.09 % and 13.28 ± 0.56 %, respectively). The optimal reaction temperature at the interface was predicted to be 80 °C under optimized conditions using the COMSOL software. This study will help in scaling this technique for large–area PSCs, optimizing the laser parameters for different perovskite compositions, and investigating the long-term stability of enhanced PSCs, boosting their commercial viability.

Determination of extracellular proteinase in L. helveticus Lh191404 based on whole genome sequencing and proteomics analysis

Lactobacillus helveticus exhibits a remarkable proteolytic system. However, the etiology of these protein hydrolysis characteristics, whether caused by extracellular proteinases (EP) or cell envelope proteinases (CEP), has been puzzling researchers. In this study, third-generation Nanopore whole genome sequencing and proteomics analysis were used to unravel the root cause of the aforementioned confusion. The genome of L. helveticus Lh191404 was 2,117,643 bp in length, with 67 secreted proteins were found. Combined with proteomic analysis, it was found that the protein composition of extraction from CEP and EP were indeed the same substance. Bioinformatics analysis indicated that the CEP belonged to the PrtH1 Variant (PrtH1_V) genotype by phylogenetic analysis. The three-dimensional structures of various domains within the PrtH1_V-191404 had been characterized, providing a comprehensive understanding of its structural features. Results of proteinase activity showed that the optimal reaction temperature was 40 °C, with a pH of 6.50. These findings suggested that the origin of EP in L. helveticus Lh191404 may be due to CEP being released into the substrate after detaching from the cell wall. This research is of guiding significance for further understanding the operational mechanism of the protein hydrolysis system in lactic acid bacteria.

Decorated gelatin polymer onto copper aluminum layered double hydroxides for superior removal of Congo red: Optimization and adsorption evaluation of kinetics, isotherms, and thermodynamics

Azo-dyes are highly soluble in water and well documented by their toxic and nonbiodegradable characters and the removal of such dye pollutants from wastewater is aimed to control environmental pollution. Therefore, the current study is designed and executed to efficiently remove Congo Red dye pollutant (CRDP) as an example of azo-dye coloring materials by using a newly synthesized nanobiosorbent. The aimed Cu/Al-LDHs@Gltn nanobiosorbent was prepared by the direct combination and binding of gelatin as a sustainable biopolymeric material with copper aluminum layered double hydroxides (Cu/Al-LDHs) by using a green microwave synthesis approach. Several characterization techniques were applied to confirm the morphology and structure of Cu/Al-LDHs@Gltn. The particle size range was identified by using the SEM analysis from 16.54 nm to 30.68 nm and the EDX investigation confirmed the elemental existence of C (25.1%), O (41.9%), and N (13.5%), Al (3.2%), Cu (11.9%) and Cl (4.4%) elements. The FT-IR analysis referred to the incorporation of several surface functionalizations as –OH, COOH, metal-O and others, while the BET-surface area configuration was detected (41.35 m2 g−1). Zero-charge point of Cu/Al-LDHs@Gltn was also measured to provide (pHzpc = 6.0). The significant controlling parameters were testified to optimize the pollutant adsorption onto the aimed Cu/Al-LDHs@Gltn via batch removal experiments by using 5-15 mg/L CRDP concentrations. The optimum pH (2.0), reaction duration (35 min), dosage (15 mg) and reaction temperature (25°C) conditions were concluded. Several related models to adsorption isotherm and kinetic studies were explored. The thermodynamic parameters additionally estimated the spontaneity and the exothermal adsorptive reaction of CRDP onto Cu/Al-LDHs@Gltn. This was confirmed to afford high stability and sustainability providing successive efficiency up to 94.6%, 84.1% and 78.8% (1st cycle) and yielded 83.3%, 70.1% and 64.5% (3rd cycle) upon testifying 5, 10 and 15 mg/L CRDP concentrations, correspondingly. Cu/Al-LDHs@Gltn was finally characterized by excellent CRDP removal efficiency up to 92.1-95.1% (5 mg/L CRDP), 91.9-92.3% (10 mg/L CRDP) and 90.4-91.7% (15 mg/L CRDP) from drinking, sea and wastewaters, correspondingly.

Diols production from pyrolysis oil water‐soluble fraction

AbstractBACKGROUNDThe production of value‐added chemicals from pyrolysis oil or its fractions is of great significance for the valorization of biomass. Diols, including ethylene glycol (EG) and 1,2‐propylene glycol (1,2‐PG), are important bulk chemicals with widespread industrial applications. Here we investigated the production of diols from pyrolysis oil water‐soluble fraction (WS) using a hybrid catalyst (Ni + H2WO4).RESULTSFirstly, levoglucosan, glycolaldehyde and acetol, three main components in WS, were respectively selected as the single model compound, and their respective conversions into diols were investigated at different temperatures for different reaction times. The result showed the optimum reaction temperature and time were 180 °C and 2 h respectively, under which a EG yield of 53.8% and 1,2‐PG yield of 5.2% were obtained from levoglucosan conversion, a EG yield of 98.6% was obtained from glycolaldehyde conversion, and a 1,2‐PG yield of 98.5% was obtained from acetol conversion. The reaction pathway of levoglucosan conversion was analyzed. Secondly, the model mixture of levoglucosan, glycolaldehyde and acetol was used to simulate the real WS, and their conversion was investigated at different ratios of H2WO4 to Ni. The result showed the optimum catalyst composition was 0.15 g H2WO4 and 0.3 g Ni, under which a EG yield of 76.4% and 1,2‐PG yield of 38.4% were obtained. Thirdly, the real original WS was converted under the optimum reaction conditions and the result only gave a EG yield of 19.1% and 1,2‐PG yield of 25.8% (based on the carbon moles of main substrates), which were much less than the two yields of model mixture. That was related to the presences of other types of chemicals in original WS. After the original WS being adsorbed by activated carbon, the yields of EG and 1,2‐PG could be increased to 39.2% and 37.9%, respectively.CONCLUSIONThe presences of certain other types of chemicals (such as acids, furans, phenolics and cyclopentanones) in original WS inhibited the production of diols. The activated carbon adsorption could efficiently remove most of furans, phenolics and cyclopentanones in original WS and increased significantly the diols yields. © 2024 Society of Chemical Industry (SCI).

A Loop-Mediated Isothermal Amplification Assay for the Rapid Detection of Didymella segeticola Causing Tea Leaf Spot.

Tea leaf spot caused by Didymella segeticola is an important disease that threatens the healthy growth of tea plants (Camellia sinensis) and results in reductions in the productivity and quality of tea leaves. Early diagnosis of the disease is particularly important for managing the infection. Loop-mediated isothermal amplification (LAMP) assay is an efficient diagnostic technique with the advantages of simplicity, specificity, and sensitivity. In this study, we developed a rapid, visual, and high-sensitivity LAMP assay for D. segeticola detection based on sequence-characterized amplified regions. Two pairs of amplification primers (external primers F3 and B3 and internal primers FIP and BIP) were designed based on a specific sequence in D. segeticola (NCBI accession number: OR987684). Compared to common pathogens of other genera in tea plants and other species in the Didymella genus (Didymella coffeae-arabicae, Didymella pomorum, and Didymella sinensis), the LAMP method is specific for detecting the species D. segeticola. The assay was able to detect D. segeticola at a minimal concentration of 1 fg/μL genomic DNA at an optimal reaction temperature of 65 °C for 60 min. When healthy leaves were inoculated with D. segeticola in the laboratory, the LAMP method successfully detected D. segeticola in diseased tea leaves at 72 h post inoculation. The LAMP assays were negative when the DNA samples were extracted from healthy leaves. Leaf tissues with necrotic lesions from 18 germplasms of tea plants tested positive for the pathogen by the LAMP assay. In summary, this study established a specific, sensitive, and simple LAMP method to detect D. segeticola, which provides reliable technical support for estimating disease prevalence and facilitates sustainable management of tea leaf spot.

Modified sodium alginate-based three-dimensional network hydrogel dust suppressant: Preparation, characterization, and performance

Chemical dust suppression is typically associated with high economic costs, unclear efficacy, and poor degradability. In this study, sodium alginate (SA) was extracted from kelp and cross-linked with polyvinyl alcohol (PVA) and polyacrylamide (PAM). Sulfonated castor oil (CAS) was subsequently added to generate a three-dimensional network hydrogel dust suppressant (PVA-SA-PAM/CAS). Using single-factor experiments, the optimal reaction temperature (60 °C) and dosages of PVA, PAM, and the cross-linking agent (2.5, 4.5, and 0.1 g, respectively) were determined. The viscosity and compressive strength of the prepared hydrogel were 86 mPa·s and 218 kPa, respectively, which meet the requirements for mine dust suppression. Various analyses revealed the hydrogel's reaction process and microstructure changes. Additionally, thermogravimetric experiments proved that the hydrogel had good thermal stability. The specific surface area and pore size of the hydrogel were 0.0278 m2/g and 11.8 nm, respectively, improving its adsorption capacity. Additionally, PVA-SA-PAM/CAS exhibited a good water retention rate. The dust suppression efficiency of PVA-SA-PAM/CAS was >98 % under strong winds (12 m/s). Moreover, the degradation rate of PVA-SA-PAM/CAS was 37 % after eight cycles (56 d) under environmental conditions. Therefore, PVA-SA-PAM/CAS exhibits good wetting, dust suppression, and degradation properties, which can effectively alleviate mine dust pollution.

Optimizing removal of elemental mercury from flue gas using halide‐impregnated red mud

AbstractMercury (Hg0) emission from coal‐fired industrial plants poses severe threats to ecosystem sustainability and human health, urging the development of novel and cost‐effective adsorbents to treat industrial flue gas. Herein, the modification of industrial residual red mud (RM) through the impregnation of hydrogen halides (HH) and its adsorption characteristics for removing elemental mercury from combustion flue gas was reported. Experimental investigation of HH‐modified RM reveals that the hydrogen iodide (HI)‐modified RM with a concentration of 1.5 M had a maximum Hg0 removal efficiency of 98%, whereas hydrogen bromide (HBr) 1.5 M modified RM had a maximum Hg0 removal efficiency of 90%. The effect of various parameters, such as reaction temperature and halide concentrations, were also found to be influential for the adsorption efficiency of the modified RM. Moreover, it is important to highlight the chemisorption characteristics of HI‐modified RM, which significantly enhances the efficiency of the removal process. The Hg0 removal efficiency increases with the increase in HI concentration (1.5 M @ 93%) with an optimal reaction temperature of 140°C. Furthermore, the maximum Hg0 removal attained with a change in NO concentration was 98% at 200 ppm. However, increasing the SO2 concentration reduces the efficiency of RM for removing Hg0 in simulated coal combustion flue gas. The pseudo‐second‐order model (R2 = 0.98) accurately describes the adsorption of in kinetic investigations, indicating a chemisorption mechanism. This analysis of the chemisorption mechanism highlights the efficiency of halide‐modified industrial solid waste, which has the potential to be used in the design of economical and innovative adsorbents for reducing environmental pollution. The present study employed specific reaction parameters such as reaction temperature, halide loading contents, and different flue gas compositions, which had not been extensively explored.

The treatment strategies of autoimmune hemolytic anemia

Autoimmune hemolytic anemia (AIHA) is characterized by the accelerated destruction of erythrocytes due to the presence of antibodies and/or complement that bind to antigens on erythrocytes. It can be subdivided into warm, cold or mixed AIHA based on the type of autoantibody and the optimal temperature of antigen-antibody reaction. Glucocorticoid with or without rituximab is the first-line treatment of warm AIHA (wAIHA), and splenectomy was once the preferred second-line treatment for relapsed or refractory wAIHA. However, due to the various complications of splenectomy, rituximab has gradually become the preferred treatment for patients who have failed glucocorticoid therapy. Other available treatments including immunosuppressants and plasma exchange can be chosen. Rituximab with or without bendamustine is generally taken as the first-line regimen for cold autoimmune hemolytic anemia (cAIHA), while glucocorticoid and splenectomy are ineffective. Sutimlimab, a kind of complement inhibitor, has been approved for the treatment of cold agglutinin disease (CAD). In recent years, many new drugs have emerged as treatment options for AIHA. Emerging therapies, including B-cell-directed therapies, plasma cell-directed therapies, complement inhibitors, and phagocytosis inhibition, provide a new perspective for AIHA therapy, showing great potential for clinical applications.

Dual Gene Detection of H5N1 Avian Influenza Virus Based on Dual RT-RPA.

The H5N1 avian influenza virus seriously affects the health of poultry and humans. Once infected, the mortality rate is very high. Therefore, accurate and timely detection of the H5N1 avian influenza virus is beneficial for controlling its spread. This article establishes a dual gene detection method based on dual RPA for simultaneously detecting the HA and M2 genes of H5N1 avian influenza virus, for the detection of H5N1 avian influenza virus. Design specific primers for the conserved regions of the HA and M2 genes. The sensitivity of the dual RT-RPA detection method for HA and M2 genes is 1 × 10-7 ng/μL. The optimal primer ratio is 1:1, the optimal reaction temperature is 40 °C, and the optimal reaction time is 20 min. Dual RT-RPA was used to detect 72 samples, and compared with RT-qPCR detection, the Kappa value was 1 (p value < 0.05), and the clinical sample detection sensitivity and specificity were both 100%. The dual RT-RPA method is used for the first time to simultaneously detect two genes of the H5N1 avian influenza virus. As an accurate and convenient diagnostic tool, it can be used to diagnose the H5N1 avian influenza virus.

The types of metal M and crystal surface in the PtM (M = Co, Ni, Zn) IMCs catalysts to regulate catalytic performance of ethane direct dehydrogenation

PtM IMCs have improved catalytic performance of ethane dehydrogenation (EDH), however, identifying the functions of the types of metal M and crystal surface for the PtM IMCs catalysts in regulating EDH catalytic performance are still a challenge in experiment. This work fully investigated catalytic performance of EDH over three crystal surfaces (110), (111) and (200) of PtM IMCs (M = Co, Ni, Zn) by using density functional theory (DFT) calculations and kinetic Monte Carlo (kMC) simulations. The results show that the catalytic performance of EDH over PtM IMCs strongly depend on the types of metal M and crystal surfaces, the PtZn(111) catalyst is screened out as the most promising in EDH reaction with the optimal reaction temperature of 773.15 K. The geometrically isolated Pt site in the [PtM3] assembly of PtZn(111) could catalyze the CH cleavage, and C2H4* exhibits weak π-adsorption model at the individual Pt sites, promoting C2H4* desorption. Compared to (110) and (200) surfaces, the (111) surface with moderate Bader charge transfer showed the highest C2H4(g) production activity, and Zn atoms transferred more electrons to Pt atoms, which greatly weakened the charge transfer between C2H4* and the catalyst surface, favoring C2H4* desorption to inhibit C2H4* deep dehydrogenation. Moreover, the catalytic performance of PtZn(111) catalyst is superior to the industrially used PtSn catalyst. This work provides valuable structure clue for the design of high-performance catalyst in alkane direct dehydrogenation.

Organoborane Se and Te Precursors for Controlled Modulation of Reactivity in Nanomaterial Synthesis.

To exploit the distinctive optoelectrical properties of nanomaterials, precise control over the size, morphology, and interface structure is essential. Achieving a controlled synthesis demands precursors with tailored reactivity and optimal reaction temperatures. Here, we introduce organoborane-based selenium and tellurium precursors borabicyclononane-selenol (BBN-SeH) and tellurol (BBN-TeH). The reactivity of these precursors can be modified by commercially available additives, covering a wide range of intermediate reactivity and filling significant reactivity gaps in existing options. By allowing systematic adjustment of growth conditions, they achieve the controlled growth of quantum dots of various sizes and materials. Operating via a surface-assisted conversion mechanism, these precursors rely on surface coordination for activation and undergo quantitative deposition on coordinating surfaces. These properties allow precise control over the radial distribution and density of different chalcogenide atoms within the nanoparticles. Diborabicyclononanyl selane ((BBN)2Se), an intermediate from the BBN-SeH synthesis, can also serve as a selenium precursor. While BBN-SeH suppresses nucleation, (BBN)2Se exhibits efficient nucleation under specific conditions. By leveraging these distinct activation behaviors, we achieved a controlled synthesis of thermally stable nanoplates with different thicknesses. This study not only bridges critical reactivity gaps but also provides a systematic methodology for precise nanomaterial synthesis.

Identification of a Novel Chitinase from Bacillus paralicheniformis: Gene Mining, Sequence Analysis, and Enzymatic Characterization.

In this study, a novel strain for degrading chitin was identified as Bacillus paralicheniformis HL37, and the key chitinase CH1 was firstly mined through recombinant expression in Bacillus amyloliquefaciens HZ12. Subsequently, the sequence composition and catalytic mechanism of CH1 protein were analyzed. The molecular docking indicated that the triplet of Asp526, Asp528, and Glu530 was a catalytic active center. The enzymatic properties analysis revealed that the optimal reaction temperature and pH was 65 °C and 6.0, respectively. Especially, the chitinase activity showed no significant change below 55 °C and it could maintain over 60% activity after exposure to 85 °C for 30 min. Moreover, the optimal host strain and signal peptide were obtained to enhance the expression of chitinase CH1 significantly. As far as we know, it was the first time finding the highly efficient chitin-degrading enzymes in B. paralicheniformis, and detailed explanations were provided on the catalytic mechanism and enzymatic properties on CH1.

Molecular engineering of PETase for efficient PET biodegradation

The widespread utilization of polyethylene terephthalate (PET) has caused a variety of environmental and health problems. Compared with traditional thermomechanical or chemical PET cycling, the biodegradation of PET may offer a more feasible solution. Though the PETase from Ideonalla sakaiensis (IsPETase) displays interesting PET degrading performance under mild conditions; the relatively low thermal stability of IsPETase limits its practical application. In this study, enzyme-catalysed PET degradation was investigated with the promising IsPETase mutant HotPETase (HP). On this basis, a carbohydrate-binding module from Bacillus anthracis (BaCBM) was fused to the C-terminus of HP to construct the PETase mutant (HLCB) for increased PET degradation. Furthermore, to effectively improve PET accessibility and PET-degrading activity, the truncated outer membrane hybrid protein (FadL) was used to expose PETase and BaCBM on the surface of E. coli (BL21with) to develop regenerable whole-cell biocatalysts (D-HLCB). Results showed that, among the tested small-molecular weight ester compounds (p-nitrophenyl phosphate (pNPP), p-Nitrophenyl acetate (pNPA), 4-Nitrophenyl butyrate (pNPB)), PETase displayed the highest hydrolysing activity against pNPP. HP displayed the highest catalytic activity (1.94 μM(p-NP)/min) at 50 °C and increased longevity at 40 °C. The fused BaCBM could clearly improve the catalytic performance of PETase by increasing the optimal reaction temperature and improving the thermostability. When HLCB was used for PET degradation, the yield of monomeric products (255.7 μM) was ∼25.5 % greater than that obtained after 50 h of HP-catalysed PET degradation. Moreover, the highest yield of monomeric products from the D-HLCB-mediated system reached 1.03 mM. The whole-cell catalyst D-HLCB displayed good reusability and stability and could maintain more than 54.6 % of its initial activity for nine cycles. Finally, molecular docking simulations were utilized to investigate the binding mechanism and the reaction mechanism of HLCB, which may provide theoretical evidence to further increase the PET-degrading activities of PETases through rational design. The proposed strategy and developed variants show potential for achieving complete biodegradation of PET under mild conditions.

Establishment and evaluation of a new fluorescent probe method based on loop-mediated isothermal amplification for the detection of Mycobacterium tuberculosis complex.

We aimed to develop a novel diagnostic method called multiplex fluorescence of loop primer upon self-dequenching loop-mediated isothermal amplification (mFLOS-LAMP) for the rapid detection of Mycobacterium tuberculosis complex (MTBC). A set of specific primers was designed to target the detection of IS1081 and IS6110 genes, which are insertion sequences within the MTBC. The 110 sputum specimens collected were assessed using the established mFLOS-LAMP method, multiplex polymerase chain reaction, Xpert MTB/RIF, and smear microscopy. The optimal reaction temperature and duration for mFLOS-LAMP were determined to be 65°C and 30 min, respectively, by optimizing the entire system. The detection sensitivity of mFLOS-LAMP was 6.0 × 101 CFU/mL, by Bacillus Calmette-Guerin, and the mFLOS-LAMP sensitivity of M. tuberculosis H37Rv genomic DNA was 500 fg, and the specificity was 100%. The sensitivity of mFLOS-LAMP was 94.2% and the specificity was 96.6%, when Xpert MTB/RIF was used as the reference method. There was no statistically significant difference in their detection rate (χ2 = 0, P = 1.000), and the consistency was good (kappa = 0.909, P < 0.001). The receiver operating characteristic analysis yielded the maximum area under the curve of 0.954. The mFLOS-LAMP method demonstrated high sensitivity and specificity, allowing for swift and accurate detection of MTBC.