Coupling of gene regulation and carrier modification manipulates bacterial biofilms as robust living catalysts

The biofilm of an engineered strain is limited by slow growth and low yield, resulting in an unsatisfactory ability to resist external stress and promote catalytic efficiency. Here, biofilms used as robust living catalysts were manipulated through dual functionalized gene regulation and carrier modification strategies. The results showed that gene overexpression regulates the autoinducer-2 activity, extracellular polymeric substance content and colony behavior of Escherichia coli, and the biofilm yield of csgD overexpressed strains increased by 79.35 % compared to that of the wild type strains (p < 0.05). In addition, the hydrophilicity of polyurethane fibres modified with potassium dichromate increased significantly, and biofilm adhesion increased by 105.80 %. Finally, the isoquercitrin yield in the catalytic reaction of the biofilm reinforced by the csgD overexpression strain and the modified carrier was 247.85 % higher than that of the untreated group. Overall, this study has developed engineered strains biofilm with special functions, providing possibilities for catalytic applications.

Molecular modification and biotechnological applications of microbial aspartic proteases

The growing preference for incorporating microbial aspartic proteases in industries is due to their high catalytic function and high degree of substrate selectivity. These properties, however, are attributable to molecular alterations in their structure and a variety of other characteristics. Molecular tools, functional genomics, and genome editing technologies coupled with other biotechnological approaches have aided in improving the potential of industrially important microbial proteases by addressing some of their major limitations, such as: low catalytic efficiency, low conversion rates, low thermostability, and less enzyme yield. However, the native folding within their full domain is dependent on a surrounding structure which challenges their functionality in substrate conversion, mainly due to their mutual interactions in the context of complex systems. Hence, manipulating their structure and controlling their expression systems could potentially produce enzymes with high selectivity and catalytic functions. The proteins produced by microbial aspartic proteases are industrially capable and far-reaching in regulating certain harmful distinctive industrial processes and the benefits of being eco-friendly. This review provides: an update on current trends and gaps in microbial protease biotechnology, exploring the relevant recombinant strategies and molecular technologies widely used in expression platforms for engineering microbial aspartic proteases, as well as their potential industrial and biotechnological applications.

Single Crystal Seed Induced Epitaxial Growth Stabilizes α-FAPbI3 in Perovskite Solar Cells

FAPbI3 stands out as an ideal candidate for the photoabsorbing layer of perovskite solar cells (PSCs), showcasing outstanding photovoltaic properties. Nonetheless, stabilizing photoactive α-FAPbI3 remains a challenge due to the lower formation energy of the competitive photoinactive δ-phase. In this study, we employ tetraethylphosphonium lead tribromide (TEPPbBr3) single crystals as templates for the epitaxial growth of PbI2. The strategic use of TEPPbBr3 optimizes the evolution of intermediates and the crystallization kinetics of perovskites, leading to high-quality and phase-stable α-FAPbI3 films. The TEPPbBr3-modified perovskite exhibits optimized carrier dynamics, yielding a champion efficiency of 25.13% with a small voltage loss of 0.34 V. Furthermore, the target device maintains 90% of its initial PCE under maximum power point (MPP) tracking over 1000 h. This work establishes a promising pathway through single crystal seed based epitaxial growth for achieving satisfactory crystallization regulation and phase stabilization of α-FAPbI3 perovskites toward high-efficiency and stable PSCs.

Longitudinal Study of Paralytic Shellfish Toxins along Canada's Coast

Paralytic shellfish toxins (PST) in shellfish products have led to severe risks to human health. To monitor the risk, the Canadian Shellfish Sanitation Program has been collecting longitudinal PST measurements in blue mussel (Mytilus edulis) and soft-shell clam (Mya arenaria) samples in six coastal provinces of Canada. The spatial distributions of major temporal variation patterns were studied via Functional Principal Component Analysis. Seasonal increases in PST contamination were found to vary the most in terms of magnitude along the coastlines, which provides support for location-specific management of the time-sensitive PST contamination. In British Columbia, the first functional principal component (FPC1) indicated the variance among the magnitudes, while FPC2 indicated the seasonality of the PST levels, which tended to be positively correlated with the abundance of dianoflagellates Alexandrium spp., and negatively with precipitation and inorganic nutrients. These findings indicate the underlying mechanism of PST variation in various geographical settings. In New Brunswick, Prince Edward, and Nova Scotia, the top FPCs indicated that the PST contamination differed mostly in the seasonal increase of the PST level during summer.

Biochemical and protein nutritional potential of mulberry (Morus alba L.) leaf: partial substitution improves the nutrition of conventional protein

BACKGROUND

With the requirements of environmental, cost and economic sustainability, new sources of alternative proteins in the livestock industry are receiving increasing attention. Mulberry (Morus alba L.) leaves are a unique feed resource because of their high protein content and large availability. Therefore, mining sustainable protein suitable for the animal husbandry industry in sericulture resources could achieve a win-win situation.

RESULTS

The protein content in mulberry leaves is 232.10-386.16 g kg-1 , and the mean value of crude fat content is 43.76 ± 8.48 g kg-1 , which has the advantages of protein content and energy. In addition, the average content of phytic acid in mulberry leaves is only 1.88 ± 0.56 g kg-1 , which means that it is not inhibited in terms of nutrient absorption. Meanwhile, the digestibility of protein was Bean pulp > Sample 8 ≈ Alfalfa ≈ Sample 13 ≈ Cottonseed meal > Fish meal, and the β-turn and particle size of mulberry leaf protein are more conducive to digestion in vitro. Furthermore, the protein of Sample 13 had the richest essential amino acids (252.00 g kg-1 ) and the highest essential amino acid index (EAAI), which was superior to conventional feed protein. In addition, the partial substitution of mulberry leaf protein (15%) significantly increased the EAAI value of conventional feed protein. However, to balance nutrition, it is necessary to combine mulberry leaf protein with other proteins to further broaden its application field.

CONCLUSION

Mulberry leaves are a new source of feed protein, which helps to alleviate the two major problems of mulberry resource surplus and feed protein resource shortage. © 2023 Society of Chemical Industry.

Silkworm pupae protein co-degradation by magnetic nanoparticles immobilized proteinase K and Mucor circinelloides aspartic protease for further utilization of sericulture by-products

Silkworm pupae, by-product of sericulture industry, is massively discarded. The degradation rate of silkworm pupae protein is critical to further employment, which reduces the impact of waste on the environment. Herein, magnetic Janus mesoporous silica nanoparticles immobilized proteinase K mutant T206M and Mucor circinelloides aspartic protease were employed in the co-degradation. The thermostability of T206M improved by enhancing structural rigidity (t1/2 by 30 min and T50 by 5 °C), prompting the degradation efficiency. At 65 °C and pH 7, degradation rate reached the highest of 61.7%, which improved by 26% compared with single free protease degradation. Besides, the immobilized protease is easy to separate and reuse, which maintains 50% activity after 10 recycles. Therefore, immobilized protease co-degradation was first applied to the development and utilization of silkworm pupae resulting in the release of promising antioxidant properties and reduces the environmental impact by utilizing a natural and renewable resource.

Effect of noise isolation using noise-cancelling headphones during laparoscopic surgery for postoperative pain reduction: A randomized clinical trial

STUDY OBJECTIVE

Most laparoscopic surgeries under general anesthesia are performed in noisy environments, although the effect of intraoperative noise reduction on postoperative pain remains uncertain. This study aimed to explore whether postoperative pain could be reduced through the intraoperative use of noise-cancelling headphones.

DESIGN

This study was conducted as a prospective parallel-group randomized clinical trial.

SETTING

Operating room and surgery room.

PATIENTS

Ninety patients who underwent laparoscopic surgery under general anesthesia.

INTERVENTIONS

In the intervention group, noise-cancelling headphones were used to reduce noise intensity during laparoscopic surgery under general anesthesia.

MEASUREMENTS

The primary outcome was the maximum movement-evoked pain intensity within 24 h post-surgery, measured using a 10-point numeric rating scale. Secondary outcomes included the maximum resting pain score and total opioid consumption during the 24-h period post-surgery. Mean intraoperative noise and the proportion of intraoperative time with noise intensity ≥70 dB were recorded.

MAIN RESULTS

The maximum movement-evoked pain score was significantly lower in the intervention group than in the control group (mean score [SD], 2.7 [1.0] and 4.0[1.0], respectively; P < 0.001). The intervention group required significantly fewer opioids than the control group (mean [SD], 44.2 [12.8] and 51.3[17.5] mg, respectively; P = 0.032). In the control group, but not the intervention group, all postoperative pain scores were significantly associated with the proportion of intraoperative time with noise intensity ≥70 dB, which was an independent risk factor for postoperative pain.

CONCLUSION

During laparoscopic surgery under general anesthesia, intraoperative noise isolation using noise-cancelling headphones is a safe and effective strategy for relieving postoperative pain and decreasing total opioid analgesic consumption.

Effect of intraoperative noise on postoperative pain in surgery patients under general anesthesia: evidence from a prospective study and mouse model

BACKGROUND

Most patients are in a noisy environment during abdominal surgery under general anesthesia. This study included patients who underwent abdominal surgery under general anesthesia and established an animal model to determine whether intraoperative noise affects postoperative pain.

MATERIALS AND METHODS

This prospective study included 200 patients who underwent abdominal surgery under general anesthesia. Intraoperative noise and electroencephalograms were continuously recorded, and the mean level and time proportion of noise intensity of greater than 70 dB were calculated. Maximum postoperative pain was assessed using a numerical rating scale at 0-12 h and 12-24 h after surgery, and postoperative analgesia consumption in patients receiving patient-controlled intravenous analgesia was recorded. Postoperative pain intensity and electroencephalogram amplitude were compared between patients with high-noise exposure (time proportion of noise intensity greater than 70 dB ≥40%) and low-noise exposure (<40%). Mechanical pain sensitivity was tested in two groups of mice with plantar incisions exposed to 40 dB or 70-100 dB.

RESULTS

The time proportion of noise intensity greater than 70 dB was identified as an independent risk factor for postoperative pain intensity ( P <0.001). P ain numerical rating scale 0-12 h (4.5±1.5 vs. 3.7±1.3, P =0.001) and 12-24 h (3.9±1.5 vs. 3.2±1.1, P =0.004) after surgery in patients with high-noise exposure was significantly higher than in patients with low-noise exposure. The electroencephalogram amplitude of patients with high-noise exposure was significantly lower than that of patients with low-noise exposure ( P <0.05). In the mouse model, mechanical hyperalgesia in the 70-100 dB group was significantly greater than that in the 40 dB group ( P <0.001).

CONCLUSION

High-level intraoperative noise exposure aggravates the degree of postoperative pain and analgesic needs of patients undergoing abdominal surgery, which may be related to the impact of noise on the neurophysiological activity of the brain and postoperative hyperalgesia.

Dynamics of fecal coliform bacteria along Canada's coast

The vast coastline provides Canada with a flourishing seafood industry including bivalve shellfish production. To sustain a healthy bivalve molluscan shellfish production, the Canadian Shellfish Sanitation Program was established to monitor the health of shellfish harvesting habitats, and fecal coliform bacteria data have been collected at nearly 15,000 marine sample sites across six coastal provinces in Canada since 1979. We applied Functional Principal Component Analysis and subsequent correlation analyses to find annual variation patterns of bacteria levels at sites in each province. The overall magnitude and the seasonality of fecal contamination were modelled by functional principal component one and two, respectively. The amplitude was related to human and warm-blooded animal activities; the seasonality was strongly correlated with river discharge driven by precipitation and snow melt in British Columbia, but such correlation in provinces along the Atlantic coast could not be properly evaluated due to lack of data during winter.

Odorant-Binding Protein 6 Contributes High Binding Affinity to Insecticides in a Parasitic Wasp Meteorus pulchricornis (Hymenoptera: Braconidae)

Meteorus pulchricornis is a preponderant parasitic wasp of various lepidopteran pests. The extensive application of broad-spectrum insecticides usually causes serious threats to the olfactory recognition of nontarget insects such as parasitoid wasps. However, the binding mechanism of odorant-binding proteins (OBPs) to insecticides in parasitoid wasps remains unknown. Herein, we find that the MpulOBP6 protein had a strong binding affinity to three insecticides (phoxim, chlorpyrifos, and chlorfenapyr). Results of computational simulations revealed that the hydrophobic interaction contributed by a mass of nonpolar amino acid residues was the primary driving force in the formation and stabilization of MpulOBP6-insecticide complexes. Among them, four residues (Met75, Val84, Phe121, and Pro122) and two residues (Val84 and Phe111) play an essential role in the binding of MpulOBP6 to phoxim and chlorfenapyr, respectively. Our findings could be instrumental to elucidate the effects of insecticide application toward the olfactory recognition of nontarget insects in the processes of agricultural production.

Radical polymeric p-doping and grain modulation for stable, efficient perovskite solar modules

High-quality perovskite light harvesters and robust organic hole extraction layers are essential for achieving high-performing perovskite solar cells (PSCs). We introduce a phosphonic acid-functionalized fullerene derivative in mixed-cation perovskites as a grain boundary modulator to consolidate the crystal structure, which enhances the tolerance of the film against illumination, heat, and moisture. We also developed a redox-active radical polymer, poly(oxoammonium salt), that can effectively p-dope the hole-transporting material by hole injection and that also mitigates lithium ion diffusion. Power conversion efficiencies of 23.5% for 1-square-centimeter mixed-cation-anion PSCs and 21.4% for 17.1-square-centimeter minimodules were achieved. The PSCs retained 95.5% of their initial efficiencies after 3265 hours at maximum power point tracking under continuous 1-sun illumination at 70° ± 5°C.

Asn57 N-glycosylation promotes the degradation of hemicellulose by β-1,3-1,4-glucanase from Rhizopus homothallicus

N-glycosylation alters the properties of different enzymes in different ways. Rhizopus homothallicus was first described as an environmental isolate from desert soil in Guatemala. A new gene encoding glucanase RhGlu16B was identified in R. homothallicus. It had high specific activity (9673 U/mg) when barley glucan was used as a substrate, and β-glucan is hemicellulose that is abundant in nature. RhGlu16B has only one N-glycosylation site in its Ala55-Gly64 loop. It was found that N-glycosylation increased its T_m value and catalytic efficiency by 5.1 °C and 59%, respectively. Adding N-glycosylation to the same region of GH16 family glucanases TlGlu16A (from Talaromyces leycettanus) increased its thermostability and catalytic efficiency by 6.4 °C and 38%, respectively. In a verification experiment using GH16 family glucanases BisGlu16B (from Bisporus) in which N-glycosylation was removed, N-glycosylation also appeared to promote thermostability and catalytic efficiency. N-glycosylation reduced the overall root mean square deviation of the enzyme structure, creating rigidity and increasing overall thermostability. This study provided a reference for the molecular modification of GH16 family glucanases and guided the utilization of β-glucan in hemicellulose.

[Research advances on burn blister fluid]

Burns often cause the damaged tissue to produce a large amount of exudate and the formation of blisters on the wound. The burn blister fluid contains a large number of molecules related to wound healing, which can reflect the state of local tissue microenvironment of the burn wound. Analyzing relevant information such as cellular components, signal mediators, and protein molecules in burn blister fluid is helpful to understand the local reaction and tissue microenvironment of burn wounds, and then help clinical burn treatment. In this article, by understanding the production mechanism of burn blister fluid, discussing its role in wound evaluation, and integrating the research progress of burn blister fluid in proteomics, metabolomics, cellular components, and pharmacokinetics, we propose our thoughts and prospects on the research of burn blister fluid, in order to provide assistance for clinical evaluation and treatment of burn wounds, and also provide idea for the follow-up study of burn blister fluid.

A Thermal Infrared Pedestrian-Detection Method for Edge Computing Devices

The thermal imaging pedestrian-detection system has excellent performance in different lighting scenarios, but there are problems regarding weak texture, object occlusion, and small objects. Meanwhile, large high-performance models have higher latency on edge devices with limited computing power. To solve the above problems, in this paper, we propose a real-time thermal imaging pedestrian-detection method for edge computing devices. Firstly, we utilize multi-scale mosaic data augmentation to enhance the diversity and texture of objects, which alleviates the impact of complex environments. Then, the parameter-free attention mechanism is introduced into the network to enhance features, which barely increases the computing cost of the network. Finally, we accelerate multi-channel video detection through quantization and multi-threading techniques on edge computing devices. Additionally, we create a high-quality thermal infrared dataset to facilitate the research. The comparative experiments on the self-built dataset, YDTIP, and three public datasets, with other methods show that our method also has certain advantages.

[Chaihu Guizhi Decoction plus or minus formula combined with capecitabine inhibits IL-6/STAT3 signaling to suppress triple-negative breast cancer xenografts in nude mice]

OBJECTIVE

To investigate the effect of Chaihu Guizhi Decoction (CHGZD) combined with capecitabine on growth and apoptosis of subcutaneous triple-negative breast cancer xenografts in nude mice and explore the possible mechanism.

METHODS

Nude mouse models bearing subcutaneous triple-negative breast cancer xenografts were randomized into 6 groups (n=10) for treatment with distilled water (model group), low (10.62 g/kg), medium (21.23 g/kg) and high (42.46 g/kg) doses of CHGZD, capecitabine (0.2 mg/kg), or the combination of CHGZD (42.46 g/kg) and capecitabine (0.2 mg/k) once daily for 21 consecutive days. The general condition of mice was observed, and after 21-day treatments, the tumors were dissected for measurement of tumor volume and weight and histopathological examination with HE staining. Serum IL-6 levels of the mice were determined with enzyme-linked immunosorbent assay (ELISA), and the expression levels of IL-6, STAT3, p-STAT3, Bax, Bcl-2 and cyclin D1 in the tumor tissues were detected using real-time PCR and Western blotting.

RESULTS

Compared with those in the model group, the tumor-bearing mice receiving treatments with CHGZD showed significantly increased food intake with good general condition, sensitive responses, increased body weight, and lower tumor mass (P < 0.01). Compared with capecitabine treatment alone, treatment with CHGZD alone at the medium and high doses and the combined treatment all resulted in significantly higher tumor inhibition rates (P < 0.01), induced obvious tumor tissue degeneration and reduced the tumor cell density. Treatments with CHGZD, both alone and in combination with capecitabine, significantly decreased serum IL-6 level, lowered the mRNA expression levels of IL-6 and STAT3, the protein expressions of IL-6, STAT3 and P-STAT3 (P < 0.05), and the mRNA and protein expressions of Bcl-2 and cyclin D1 (P < 0.05), and increased the mRNA and protein expressions of Bax in the tumor tissues (P < 0.05).

CONCLUSION

CHGZD combined with capecitabine can significantly inhibit tumor growth in nude mice bearing triple-negative breast cancer xenografts, the mechanism of which may involve the inhibition of IL-6/STAT3 signaling pathway and regulation of Bax, Bcl-2 and cyclin D1 expressions to suppress tumor cell proliferation and differentiation and induce cell apoptosis.

Lowering energy consumption for fermentable sugar production from Ramulus mori: Engineered xylanase synergy and improved pretreatment strategy

Biorefinery of Ramulus mori with lower energy consumption through improved enzyme and pretreatment strategies was reported. Directed evolution and saturation mutagenesis were used for the modification of xylanase, the yield of fermentable sugars and the degree of synergy (DS) were determined for different pretreatment (seawater/non-seawater) and enzyme treatment groups (xylanase/cellulase/co-treatment). The dominant mutant I133A/Q143Y of Bispora sp. xylanase XYL10C_ΔN was obtained with improved specific activity (1860 U/mg), catalytic efficiency (1150 mL/s∙mg) at 40 °C, and thermostability (T₅₀ increased by 7 °C). With the pretreatment of seawater immersion, the highest yield of fermentable sugars for Ramulus mori at 40 °C reached 199 μmol/g when hydrolyzed with cellulase and I133A/Q143Y, with the highest DS of 2.6; this was 4.5-fold that of the group hydrolyzed by cellulase alone with non-seawater pretreatment. Thus, bioconversion of reducing sugar from Ramulus mori was improved significantly at lower temperatures, which provides an efficient and energy-saving wayfor biofuel production.

Correction: Nutritional targeting modification of silkworm pupae oil catalyzed by a smart hydrogel immobilized lipase

Correction for 'Nutritional targeting modification of silkworm pupae oil catalyzed by a smart hydrogel immobilized lipase' by Jin-Zheng Wang et al., Food Funct., 2021, 12, 6240-6253, DOI: 10.1039/D1FO00913C.

Loop engineering of a thermostable GH10 xylanase to improve low-temperature catalytic performance for better synergistic biomass-degrading abilities

Lignocellulosic biorefining for producing biofuels poses technical challenges. It is usually conducted over a long time using heat, making it energy intensive. In this study, we lowered the energy consumption of this process through an optimized enzyme and pretreatment strategy. First, the dominant mutant M137E/N269G of Bispora sp. MEY-1XYL10C_ΔN was obtained by directed evolution with highcatalytic efficiency (970 mL/s∙mg)and specific activity (2090 U/mg)at 37 °C, and thermostability was improved (T₅₀ increased by5 °C). After pretreatment with seawater immersionfollowing steam explosion,bagasse was co-treated with cellulase and M137E/N269G under mild conditions (37 °C), the resulting highest yield of fermentable sugars reached 219 µmol/g of bagasse,46% higher than that of the non-seawater treatment group, with the highest degree of synergy of 2.0. Pretreatment with seawater following steam explosion and synergistic hydrolysis through high activity xylanase and cellulase helped to achieve low energy degradation of lignocellulosic biomass.

Improvement of XYL10C_∆N catalytic performance through loop engineering for lignocellulosic biomass utilization in feed and fuel industries

BACKGROUND

Xylanase, an important accessory enzyme that acts in synergy with cellulase, is widely used to degrade lignocellulosic biomass. Thermostable enzymes with good catalytic activity at lower temperatures have great potential for future applications in the feed and fuel industries, which have distinct demands; however, the potential of the enzymes is yet to be researched.

RESULTS

In this study, a structure-based semi-rational design strategy was applied to enhance the low-temperature catalytic performance of Bispora sp. MEY-1 XYL10C_∆N wild-type (WT). Screening and comparisons were performed for the WT and mutant strains. Compared to the WT, the mutant M53S/F54L/N207G exhibited higher specific activity (2.9-fold; 2090 vs. 710 U/mg) and catalytic efficiency (2.8-fold; 1530 vs. 550 mL/s mg) at 40 °C, and also showed higher thermostability (the melting temperature and temperature of 50% activity loss after 30 min treatment increased by 7.7 °C and 3.5 °C, respectively). Compared with the cellulase-only treatment, combined treatment with M53S/F54L/N207G and cellulase increased the reducing sugar contents from corn stalk, wheat bran, and corn cob by 1.6-, 1.2-, and 1.4-folds, with 1.9, 1.2, and 1.6 as the highest degrees of synergy, respectively.

CONCLUSIONS

This study provides useful insights into the underlying mechanism and methods of xylanase modification for industrial utilization. We identified loop2 as a key functional area affecting the low-temperature catalytic efficiency of GH10 xylanase. The thermostable mutant M53S/F54L/N207G was selected for the highest low-temperature catalytic efficiency and reducing sugar yield in synergy with cellulase in the degradation of different types of lignocellulosic biomass.

Sweet-flavored peptides with biological activities from mulberry seed protein treated by multifrequency countercurrent ultrasonic technology

To increase the reuse of food residues, multifrequency countercurrent ultrasonic treatment was used to enhance the extraction yield of defatted mulberry seed protein (DMSP), and sweet-flavored peptides from DMSP hydrolysates (DMSPHs) were obtained for the first time. Here, the DMSP yield was increased by 16.2% (p < 0.05) while the power density was halved compared with single-frequency ultrasonic treatment. According to Fick's second law, a molecular diffusion dynamics model was developed to be suitable for predicting the pretreatment conditions (R² = 0.9785). After that, the sweet-flavored peptides were purified and the main amino acid sequences were identified, i.e., FEGGSIE, KDFPEAHSQAT, and GSQPAEGAK. Moreover, the antioxidant activities of DMSPHs prepared with tri-frequency treatment was higher than 60%. The DMSPHs retarded the growth of HepG2 cells in vitro, increased the necrotic quadrant (Q1-UL), and extended the S phase. Therefore, the sweet-flavored peptides prepared from DMSPHs using the multifrequency-ultrasonic treatment have significant biological activities.

Nutritional targeting modification of silkworm pupae oil catalyzed by a smart hydrogel immobilized lipase

To prepare a nutritional supplement using silkworm pupae oil (SPO) as a feedstock, a microfluidic reactor with a smart hydrogel immobilized lipase was first constructed to reduce the relative content of palmitic acid at sn-1,3 and improve the nutritional function. The effects of flow rate, reaction temperature, and substrate molar ratio were investigated. In vitro digestion and pH-stat models were employed to analyze the digestion feature after the modification of SPO, while HPLC-ELSD, zeta potential, DSC, and TGA were used to evaluate the nutritional function. The relative content of "OOO" and "OPO" type triglycerides was increased by 49.48% and 107.67%, and that of palmitic acid at sn-1,3 was decreased by 49.61% in 10 s. After the verification of the in vitro digestion model, the fatty acid release rate of the modified SPO was significantly improved by 22.07%, indicating the nutritional function improvement of SPO. Therefore, the nutritional function of SPO has been improved successfully by the application of a microchannel reactor with photo-immobilized lipase, which could set a reference for the utilization of insect oil resources.

Enrichment and purification of red pigments from defective mulberry fruits using biotransformation in a liquid-liquid-solid three-phase system

A large number of defective mulberries are discarded each year because mulberries are easy to break. The red pigments from defective mulberries are recognized as the sustainable sources of anthocyanins extracted from nature. Cyanidin-3-O-rutinoside and cyanidin-3-O-glucoside are the main components of mulberry red pigments, accounting for 50% and 40% of the total, respectively. Cyanidin-3-O-glucoside exhibits anticancer, hypoglycemic, and liver and visceral protection properties. Cyanidin-3-O-glucoside can be prepared by enzymatically hydrolyzing the rhamnosidase bond of cyanidin-3-O-rutinoside. To obtain mulberry red pigment with a high purity of cyanidin-3-O-glucoside, immobilized α-L-rhamnosidase was added to the aqueous two-phase system to construct a liquid-liquid-solid three-phase enzyme catalytic system. After optimization, the three-phase system was composed of 27.12% (w/w) ethanol, 18.10% (w/w) ammonium sulfate, 15% (w/w) mulberry juice, 4.24% (w/w) immobilized α-L-rhamnosidase, and 35.54% (w/w) pure water. The three-phase system was employed to enrich and purify cyanidin-3-O-glucoside at pH 5 and 45 °C for 1 h. The purity of cyanidin-3-O-glucoside was increased from 40 to 82.42% with cyanidin-3-O-rutinoside conversion of 60.68%. The immobilized α-L-rhamnosidase could be reused seven times, maintaining a relative activity of over 50%. Overall, the developed system provided an efficient and simple approach for high purity mulberry red pigment production and recycling in the field of sustainable agriculture. Graphical abstract.

An alternative solution for α-linolenic acid supplements: in vitro digestive properties of silkworm pupae oil in a pH-stat system

α-Linolenic acid (ALA) is recognised to have a regulatory effect on cardiovascular diseases. Due to the low bioavailability of linseed oil (LINO), which is the most common ALA supplement, it is necessary to find a replacement for ALA supplements that is more easily accepted by the human body. The content of ALA in silkworm pupae oil (SPO) is 32.60 ± 0.67%, and SPO can be substituted as a dietary lipid to meet the demand of the human body. In the present study, a pH-stat system was used to investigate the release degree of free fatty acids (FFAs) from SPO and construct a first-order kinetic model. Digestion experiments in vitro with different lipids showed that the maximum release FFA levels were SPO > SO (soybean oil) > LO (lard oil) > MSO (mulberry seed oil) > LINO, and the first-order kinetic apparent rate constants were LINO > SPO > LO > SO > MSO. Triacylglycerol (TAG) and fatty acid composition are the decisive factors in determining the level of lipid digestion. Therefore, the maximum level of FFAs released from SPO (84.34 ± 1.37%) was much higher than that of LINO (49.78 ± 0.52%) when the hydrolysis rates were 0.2114 s^-1 and 0.2249 s^-1, respectively. In addition, the smaller emulsion droplet size (609.24 ± 43.46 nm) and weaker surface charge (-17.93 ± 0.42 mV) also resulted in higher levels of SPO under in vitro digestion conditions. Meanwhile, due to low melting and crystallisation temperature, SPO is quickly absorbed by the human body. Overall, SPO can be used as a new alternative for ALA supplements based on its superior digestive properties.

Multifunctional Polymer-Regulated SnO2 Nanocrystals Enhance Interface Contact for Efficient and Stable Planar Perovskite Solar Cells

Perovskite solar cells (PSCs) have rapidly developed and achieved power conversion efficiencies of over 20% with diverse technical routes. Particularly, planar-structured PSCs can be fabricated with low-temperature (≤150 °C) solution-based processes, which is energy efficient and compatible with flexible substrates. Here, the efficiency and stability of planar PSCs are enhanced by improving the interface contact between the SnO₂ electron-transport layer (ETL) and the perovskite layer. A biological polymer (heparin potassium, HP) is introduced to regulate the arrangement of SnO₂ nanocrystals, and induce vertically aligned crystal growth of perovskites on top. Correspondingly, SnO₂ -HP-based devices can demonstrate an average efficiency of 23.03% on rigid substrates with enhanced open-circuit voltage (V_OC ) of 1.162 V and high reproducibility. Attributed to the strengthened interface binding, the devices obtain high operational stability, retaining 97% of their initial performance (power conversion efficiency, PCE > 22%) after 1000 h operation at their maximum power point under 1 sun illumination. Besides, the HP-modified SnO₂ ETL exhibits promising potential for application in flexible and large-area devices.

Radical Molecular Modulator for High-Performance Perovskite Solar Cells

The long-term stability of perovskite solar cells (PSCs) remains an issue impeding their commercialization. Generally, polycrystalline perovskite thin films have many defects on the grain boundaries, which affect the optoelectronic performance and stability of the devices under moisture, heat, illumination, and the presence of an electric field condition. The O-donor Lewis base is often employed to regulate the performance of PSCs such as carbonyl and carboxyl compounds. Herein, we have developed a concept of radical molecular modulation using the O-donor group for high-performance perovskite photovoltaic devices. The judiciously designed radical modulators 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), which located at the perovskite grain boundary through interaction with the perovskite surface sites, effectively passivated the surface defects while templating the formation of large grain crystal and high-quality perovskite thin films. Accordingly, the optimized TEMPO-modulated PSCs achieved a power conversion efficiency of 20.73% with superior stability. This work makes an important contribution for exploring the effect of radical in perovskites to improve the performance of PSCs and other optoelectronic devices.

Dual promoter strategy enhances co-expression of α-L-rhamnosidase and enhanced fluorescent protein for whole-cell catalysis and bioresource valorization

Developing circular economy is the only way to improve the efficiency of resource utilization. Whole-cell catalysis is an effective method to recycle enzymes, improve catalytic efficiency, and reduce production costs. The enzyme, α-L-rhamnosidase has considerable application prospects in the field of biocatalysis as it can hydrolyze a variety of α-L rhamnoses. In the present study, the genes for α-L-rhamnosidase (rhaB1) and enhanced fluorescent protein (EGFP) were co-expressed using a bi-promoter expression vector pRSFDuet1 and their enzymatic properties were evaluated. To our knowledge, this study has established an effective rhamnosidase-fluorescent indicator and whole-cell catalytic system for the first time. Moreover, we analyzed the change in the activity of the crude rhaB1-EGFP as well as its whole-cell during the biocatalysis process using fluorescence intensity. Recombinant rhaB1-EGFP as a product which contains rhaB1 and EGFP showed higher thermal stability, pH stability, and conversion efficiency than rhaB1, and its optimum temperature for rutin catalysis was ideal for industrial applications. Moreover, under the optimal conditions of a rutin concentration of 0.05 g/L, pH of 6.0, temperature of 40 °C, a yield of 92.5% was obtained. Furthermore, we demonstrated the relationship between the fluorescence intensity and enzyme activity. This study established a highly efficient whole-cell catalytic system whose activity can be evaluated by fluorescence intensity, providing a reference for enzyme recycling.

Improvement in catalytic activity and thermostability of a GH10 xylanase and its synergistic degradation of biomass with cellulase

BACKGROUND

Xylanase is one of the most extensively used biocatalysts for biomass degradation. However, its low catalytic efficiency and poor thermostability limit its applications. Therefore, improving the properties of xylanases to enable synergistic degradation of lignocellulosic biomass with cellulase is of considerable significance in the field of bioenergy.

RESULTS

Using fragment replacement, we improved the catalytic performance and thermostability of a GH10 xylanase, XylE. Of the ten hybrid enzymes obtained, seven showed xylanase activity. Substitution of fragments, M3, M6, M9, and their combinations enhanced the catalytic efficiency (by 2.4- to fourfold) as well as the specific activity (by 1.2- to 3.3-fold) of XylE. The hybrids, XylE-M3, XylE-M3/M6, XylE-M3/M9, and XylE-M3/M6/M9, showed enhanced thermostability, as observed by the increase in the T ₅₀ (3-4.7 °C) and T _m (1.1-4.7 °C), and extended t _1/2 (by 1.8-2.3 h). In addition, the synergistic effect of the mutant xylanase and cellulase on the degradation of mulberry bark showed that treatment with both XylE-M3/M6 and cellulase exhibited the highest synergistic effect. In this case, the degree of synergy reached 1.3, and the reducing sugar production and dry matter reduction increased by 148% and 185%, respectively, compared to treatment with only cellulase.

CONCLUSIONS

This study provides a successful strategy to improve the catalytic properties and thermostability of enzymes. We identified several xylanase candidates for applications in bioenergy and biorefinery. Synergistic degradation experiments elucidated a possible mechanism of cellulase inhibition by xylan and xylo-oligomers.

Inositol as a new enhancer for improving lipid production and accumulation in Schizochytrium sp. SR21

Lipids produced from agricultural and industrial residues using oleaginous microorganisms for use as biofuels are attracting the attention of researchers due to their environmental benefits. However, low efficiencies and high costs limit their application to a certain extent. The present study is the first to use inositol as an enhancer to improve the production and accumulation of lipids during fermentation by the microalga Schizochytrium sp. SR21. The study aimed to maximize the production of lipids and docosahexaenoic acid (DHA) by optimizing the conditions of inositol addition into the fermentation medium. The corresponding key enzyme and metabolite profiles of SR21 were evaluated. The results indicated that the addition of 120 mg L^-1 of inositol to the medium at 48 h improved lipid and DHA production by 13.90 and 20.82%, resulting in total concentrations of 22.86 and 8.53 g/L, respectively. Moreover, the ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs) increased by 23.38% and is consistent with the results of the metabolomic analysis. The activity of enzymes (i.e., PC, G6PDH, NADPH-ME, and ACL) related to fatty acid synthesis in strain SR21 also increased significantly (43.38%, 28.68%, 37.47%, and 19.87%, respectively). Metabolomic analysis also showed that inositol promoted lipid synthesis in SR21 and significantly increased the relative proportion of UFAs by affecting the citrate cycle and SFA and UFA metabolic pathways. Thus, inositol is an ideal enhancer of lipid production and accumulation by oleaginous microorganisms. Graphical abstract.

Plasma C-type lectin-like receptor 2 as a predictor of death and vascular events in patients with acute ischemic stroke

BACKGROUND AND PURPOSE

C-type lectin-like receptor 2 (CLEC-2) has prominent involvement in platelet activation, which is increased in coronary heart disease and acute ischaemic stroke (AIS) and is associated with stroke progression and stroke prognosis. Here, the aim was to examine the prognostic value of CLEC-2 in death and vascular event recurrence in AIS patients.

METHODS

In all, 352 patients with AIS were studied prospectively. All patients were followed up for 1 year. Death for all vascular events and a combination of death and vascular diseases (recurrent stroke, myocardial infarction, hospitalized and treated angina, hospitalized and treated peripheral arterial disease) were recorded.

RESULTS

During 1 year of follow-up, 46 patients (14.2%) experienced death or combined end-points (23 death and 46 combined end-points). Plasma CLEC-2 (pCLEC-2) was significantly associated with an increased risk of death and combined events of death and vascular diseases after adjusting for age, sex, history of hypertension, diabetes mellitus and coronary artery disease, and National Institutes of Health Stroke Scale scores. Each 1 SD higher log-transformed pCLEC-2 was associated with a 4.27-fold (hazard ratio 4.27, 95% confidence interval 1.71-10.65) increased risk for death and a 2.42-fold increased risk for combined end-points (hazard ratio 2.42, 95% confidence interval 1.52-3.86). The optimal cut-off point of pCLEC-2 for predicting death was 184.38 pg/ml.

CONCLUSIONS

Higher pCLEC-2 levels at admission were associated with increased risk of death and combined events of death and vascular diseases in patients with AIS, which indicated that pCLEC-2 is an important prognostic factor for AIS.

Functional Analysis of a Highly Active β-Glucanase from Bispora sp. MEY-1 Using Its C-terminally Truncated Mutant

A β-1,3-1,4-glucanase-encoding gene, Bisglu16B, was identified in Bispora sp. MEY-1. The deduced BisGlu16B consists of an N-terminal signal peptide, a catalytic module of glycoside hydrolase family 16 (GH16), and a C-terminal serine/proline-rich module. After expression in Pichia pastoris GS115, the purified recombinant BisGlu16B showed maximal activity at pH 4.0 and 55 °C and had broad substrate specificity (β-1,3-/β-1,4-mixed, β-1,3-, β-1,4-, and β-1,6-linked glucan, and β-1,4-mannan). The enzyme possessed high specific activities toward barley β-glucan (34 700 U·mg^-1), lichenan (23 900 U·mg^-1), and laminarin (9 000 U·mg^-1). After removing the C-terminal module, the truncated mutant, BisGlu16B-ΔC, retained similar enzymatic properties to the wild type but displayed significantly enhanced activities (up to 2.5-fold). Functional and structural analyses indicated that the C-terminal module plays a key role in the substrate binding of BisGlu16B. This study provided an excellent candidate glucanase for industrial purposes and revealed the functions of a C-terminal serine/proline-rich region.

A Biopolymer Heparin Sodium Interlayer Anchoring TiO2 and MAPbI3 Enhances Trap Passivation and Device Stability in Perovskite Solar Cells

Traps in the photoactive layer or interface can critically influence photovoltaic device characteristics and stabilities. Here, traps passivation and retardation on device degradation for methylammonium lead trihalide (MAPbI₃ ) perovskite solar cells enabled by a biopolymer heparin sodium (HS) interfacial layer is investigated. The incorporated HS boosts the power conversion efficiency from 17.2 to 20.1% with suppressed hysteresis and Shockley-Read-Hall recombination, which originates primarily from the passivation of traps near the interface between the perovskites and the TiO₂ cathode. The incorporation of an HS interfacial layer also leads to a considerable retardation of device degradation, by which 85% of the initial performance is maintained after 70 d storage in ambient environment. Aided by density functional theory calculations, it is found that the passivation of MAPbI₃ and TiO₂ surfaces by HS occurs through the interactions of the functional groups (COO^- , SO₃^- , or Na⁺ ) in HS with undersaturated Pb and I ions in MAPbI₃ and Ti⁴⁺ in TiO₂ . This work demonstrates a highly viable and facile interface strategy using biomaterials to afford high-performance and stable perovskite solar cells.

Insight into the functional roles of Glu175 in the hyperthermostable xylanase XYL10C-ΔN through structural analysis and site-saturation mutagenesis

BACKGROUND

Improving the hydrolytic performance of hemicellulases to degrade lignocellulosic biomass is of considerable importance for second-generation biorefinery. Xylanase, as the crucial hemicellulase, must be thermostable and have high activity for its potential use in the bioethanol industry. To obtain excellent xylanase candidates, it is necessary to understand the structure-function relationships to provide a meaningful reference to improve the enzyme properties. This study aimed to investigate the catalytic mechanism of a highly active hyperthermophilic xylanase variant, XYL10C-ΔN, for hemicellulose degradation.

RESULTS

By removing the N-terminal 66 amino acids, the variant XYL10C-ΔN showed a 1.8-fold improvement in catalytic efficiency and could hydrolyze corn stover more efficiently in hydrolysis of corn stover; however, it retained similar thermostability to the wild-type XYL10C. Based on the crystal structures of XYL10C-ΔN and its complex with xylobiose, Glu175 located on loop 3 was found to be specific to GH10 xylanases and probably accounts for the excellent enzyme properties by interacting with Lys135 and Met137 on loop 2. Site-saturation mutagenesis confirmed that XYL10C-ΔN with glutamate acid at position 175 had the highest catalytic efficiency, specific activity, and the broadest pH-activity profile. The functional roles of Glu175 were also verified in the mutants of another two GH10 xylanases, XylE and XynE2, which showed increased catalytic efficiencies and wider pH-activity profiles.

CONCLUSIONS

XYL10C-ΔN, with excellent thermostability, high catalytic efficiency, and great lignocellulose-degrading capability, is a valuable candidate xylanase for the biofuel industry. The mechanism underlying improved activity of XYN10C-ΔN was thus investigated through structural analysis and functional verification, and Glu175 was identified to play the key role in the improved catalytic efficiency. This study revealed the importance of a key residue (Glu175) in XYN10C-ΔN and provides a reference to modify GH10 xylanases for improved catalytic performance.

Genetic analysis of a hybrid sterility gene that causes both pollen and embryo sac sterility in hybrids between Oryza sativa L. and Oryza longistaminata

Oryza longistaminata originates from African wild rice and contains valuable traits conferring tolerance to biotic and abiotic stress. However, interspecific crosses between O. longistaminata and Oryza sativa cultivars are hindered by reproductive barriers. To dissect the mechanism of interspecific hybrid sterility, we developed a near-isogenic line (NIL) using indica variety RD23 as the recipient parent and O. longistaminata as the donor parent. Both pollen and embryo sac semi-sterility were observed in F₁ hybrids between RD23 and NIL. Cytological analysis demonstrated that pollen abortion in F₁ hybrids occurred at the early bi-nucleate stage due to a failure of the first mitosis in microspores. Partial embryo sacs in the F₁ hybrids were defective during the functional megaspore formation stage. Most notably, nearly half of the male or female gametes were aborted in heterozygotes S40ⁱS40^l, regardless of their genotypes. Thus, S40 was indicated as a one-locus sporophytic sterility gene controlling both male and female fertility in hybrids between RD23 and O. longistaminata. A population of 16 802 plants derived from the hybrid RD23/NIL-S40 was developed to fine-map S40. Finally, the S40 locus was delimited to an 80-kb region on the short arm of chromosome 1 in terms with reference sequences of cv. 93-11. Eight open reading frames (ORFs) were localized in this region. On the basis of gene expression and genomic sequence analysis, ORF5 and ORF8 were identified as candidate genes for the S40 locus. These results are helpful in cloning the S40 gene and marker-assisted transferring of the corresponding neutral allele in rice breeding programs.