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Abstract Acellular dermal matrix (ADM) is one of the most promising scaffold materials due to its ability to retain natural extracellular matrix structure. Micronized acellular dermal matrix (mADM) was prepared with no intact cell nuclei and preserved growth factors by High Hydrostatic Pressure (HHP) approach. And mADM-collagen wound dressings were developed with different proportion of type I collagen and recombinant humanized type III collagen. The porous structure of the mADM-collagen wound dressings made them a good candidate for preventing excessive fluid accumulation, while the collagens with gel-like texture combined with mADM powder to form pasty texture wound dressing, which preserving the moisture at the wound site. Moreover, the paste texture of the mADM-collagen wound dressing was easy to reshape to conform any wound shapes and body contours. Furthermore, the resulted mADM-collagen wound dressings showed good biocompatibility by supporting fibroblasts adhesion and proliferation in vitro. Subsequently, a murine model of full-thickness skin wounds was employed to assess its effects on wound healing. Notably, mADM-75% Col-I exhibited superior effects throughout the wound healing process, specifically it promoted neovascularization, skin appendage growth and new skin regeneration. This formulation closely mimicked the collagen ratio found in healthy skin, facilitating the favorable wound repair. These results indicated the superior performance of this mADM-collagen wound dressing providing an optimal environment for wound healing. Graphical Abstract

Summary: Spatial transcriptomics enables a single-cell resolution view of gene expression patterns in tissues, providing insight into their biological functions. However, applying this approach to the skin presents inherent challenges. Here, we present a protocol for preparing mammalian skin samples encompassing hair follicles for spatial transcriptomics. We describe steps for sample preparation, embedding, acquisition of frozen slices, RNA quality control, tissue mounting, fixation, staining, and imaging. We then detail procedures for permeabilization, reverse transcription, and cDNA collection.For complete details on the use and execution of this protocol, please refer to Chen et al.1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Tetanus toxin (TeNT) is one of the most toxic proteins. Neutralizing antibodies against TeNT are effective in prevention and treatment. In this study, 14 anti-tetanus nanobodies were obtained from a phage display nanobody library by immunizing a camel with the C-terminal receptor-binding domain of TeNT (TeNT-Hc) as the antigen. After fusion with the human Fc fragment, 11 chimeric heavy-chain antibodies demonstrated nanomolar binding toward TeNT-Hc. The results of toxin neutralization experiments showed that T83–7, T83–8, and T83–13 completely protected mice against 20 × the median lethal dose (LD50) at a low concentration. The neutralizing potency of T83–7, T83–8, and T83–13 against TeNT is 0.4 IU/mg, 0.4 IU/mg and 0.2 IU/mg, respectively. In the prophylactic setting, we found that 5 mg/kg of T83–13 provided the mice with full protection from tetanus, even when they were injected 14 days before exposure to 20 × LD50 TeNT. T83–7 and T83–8 were less effective, being fully protective only when challenged 7 or 10 days before exposure, respectively. In the therapeutic setting, 12 h after exposure to TeNT, 1 ~ 5 mg/kg of T83–7, and T83–8 could provide complete protection for mice against 5 × LD50 TeNT, while 1 mg/kg T83–13 could provide complete protection 24 h after exposure to 5 × LD50 TeNT. Our results suggested that these antibodies represent prophylactic and therapeutic activities against TeNT in a mouse model. The T83–7, T83–8, and T83–13 could form the basis for the subsequent development of drugs to treat TeNT toxicity.

Among all natural and synthetic toxins, botulinum neurotoxins (BoNTs), produced by Clostridium botulinum in an anaerobic environment, are the most toxic polymer proteins. Currently, the most effective modalities for botulism prevention and treatment are vaccination and antitoxin use, respectively. However, these modalities are associated with long response time for active immunization, side effects, and donor limitations. As such, the development of more promising botulism prevention and treatment modalities is warranted. Here, we designed an mRNA encoding B9-hFc – a heavy-chain antibody fused to VHH and human Fc that can neutralize BoNT serotype B (BoNT/B) effectively – and assessed its expression in vitro and in vivo. The results confirmed that our mRNA demonstrates good expression in vitro and in vivo. Moreover, a single mRNA lipid nanoparticle injection effectively prevents BoNT/B intoxication in vivo, with effects comparable to those of protein antibodies. In conclusion, we explored and clarified whether mRNA drugs encoding neutralizing antibodies prevent BoNT/B intoxication. Our results provide an efficient strategy for further research on the prevention and treatment of intoxication by botulinum toxin.

Senecavirus A (SVA) is an emerging virus that causes the vesicular disease in pigs, clinically indistinguishable from other high consequence vesicular diseases. This virus belongs to the genus Senecavirus in the family Picornaviridae. Its genome is a positive-sense, single-stranded RNA, approximately 7,300 nt in length, with a 3′ poly(A) tail but without 5′-end capped structure. SVA can efficiently propagate in different cells, including some non-pig-derived cell lines. A wild-type SVA was previously rescued from its cDNA clone using reverse genetics in our laboratory. In the present study, the BSR-T7/5 cell line was inoculated with the passage-5 SVA. At 12 h post-inoculation, SVA-infected and non-infected cells were independently collected for the analysis on comparative transcriptomics. The results totally showed 628 differentially expressed genes, including 565 upregulated and 63 downregulated ones, suggesting that SVA infection significantly stimulated the transcription initiation in cells. GO and KEGG enrichment analyses demonstrated that SVA exerted multiple effects on immunity-related pathways in cells. Furthermore, the RNA sequencing data were subjected to other in-depth analyses, such as the single-nucleotide polymorphism, transcription factors, and protein–protein interactions. The present study, along with our previous proteomics and metabolomics researches, provides a multi-omics insight into the interaction between SVA and its hosts.

Artificial multi-enzyme cascades bear great potential for bioconversion of C1 compounds to value-added chemicals. Over the past decade, massive efforts have been devoted to constructing multi-enzyme cascades to produce glycolic acid, rare functional sugars and even starch from C1 compounds. However, in contrast to traditional fermentation utilizing C1 compounds with the expectation of competitive economic performance in future industrialization, multi-enzyme cascades systems in the proof-of-concept phase are facing the challenges of upscaling. Here, we offered an overview of the recent advances in the construction of in vitro multi-enzyme cascades and whole-cell transformation using C1 compounds as substrate. In addition, the existing challenges and possible solutions were also discussed aiming to combine the strengths of in vitro and in vivo multi-enzyme cascades systems for upscaling.

BackgroundBotulinum neurotoxin (BoNT) produced by Clostridium botulinum is one of the most potent known toxins. Moreover, BoNT is classified as one of the most important biological warfare agents that threatens the biosafety of the world. Currently, the approved treatment for botulism in humans is the use of polyvalent horse serum antitoxins. However, they are greatly limited because of insufficient supply and adverse reactions. Thus, treatment of human botulism requires the development of effective toxin-neutralizing antibodies. Considering their advantages, neutralizing nanobodies will play an increasing role as BoNTs therapeutics.MethodsHerein, neutralizing nanobodies binding to the heavy chain (Hc) domain of BoNT/B (BHc) were screened from a phage display library. Then, BoNT/B-specific clones were identified and fused with the human Fc fragment (hFc) to form chimeric heavy chain antibodies. Finally, the affinity, specificity, and neutralizing activity of antibodies against BoNT/B in vivo were evaluated.ResultsThe B5-hFc, B9-hFc and B12-hFc antibodies demonstrated high affinity for BHc in the nanomolar range. The three antibodies were proven to have potent neutralizing activity against BoNT/B in vivo.ConclusionThe results demonstrate that inhibiting toxin binding to the host receptor is an efficient strategy and the three antibodies could be used as candidates for the further development of drugs to prevent and treat botulism.

Summary: Spatial transcriptomics analysis allows the examination of the biological characteristics and spatial distribution of individual lung cells at a single-cell resolution. However, due to the presence of cavities in the alveoli of the lungs, it is challenging to section them for spatial transcriptomics experiments. Here, we present a protocol for acquiring high-quality fresh mouse lung spatial transcriptomics data. We describe steps for lung perfusion, acquiring frozen slices, collecting cDNA from lung sections, and data analysis.For complete details on the use and execution of this protocol, please refer to Jiang et al.1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Abstract Botulinum neurotoxin (BoNT) shows high lethality and toxicity, marking it as an important biological threat. The only effective post-exposure therapy is botulinum antitoxin; however, such products have great potential for improvement. To prevent or treat BoNT, monoclonal antibodies (mAbs) are promising agents. Herein, we aimed to construct a bispecific antibody (termed LUZ-A1-A3) based on the anti-BoNT/A human monoclonal antibodies (HMAb) A1 and A3. LUZ-A1-A3 binds to the Hc and L-HN domains of BoNT/A, displaying potent neutralization activity against BoNT/A (124 × higher than that of HMAb A1 or HMAb A3 alone and 15 × higher than that of the A1 + A3 combination). LUZ-A1-A3 provided effective protection against BoNT/A in an in vivo mouse model. Mice were protected from infection with 500 × LD50 of BoNT/A by LUZ-A1-A3 from up to 7 days before intraperitoneal administration of BoNT/A. We also demonstrated the effective therapeutic capacity of LUZ-A1-A3 against BoNT/A in a mouse model. LUZ-A1-A3 (5 μg/mouse) neutralized 20 × LD50 of BoNT/A at 3 h after intraperitoneal BoNT/A administration and complete neutralized 20 × LD50 of BoNT/A at 0.5 h after intraperitoneal BoNT/A administration. Thus, LUZ-A1-A3 is a promising agent for the pre-exposure prophylaxis and post-exposure treatment of BoNT/A.

The remarkable regenerative ability of the skin, governed by complex molecular mechanisms, offers profound insights into the skin repair processes and the pathogenesis of various dermatological conditions. This understanding, derived from studies in human skin and various model systems, has not only deepened our knowledge of skin regeneration but also facilitated the development of skin substitutes in clinical practice. Recent research highlights the crucial role of lymphatic vessels in skin regeneration. Traditionally associated with fluid dynamics and immune modulation, these vessels are now recognized for interacting with skin stem cells and coordinating regeneration. This Mini Review provides an overview of recent advancements in basic and translational research related to skin regeneration, focusing on the dynamic interplay between lymphatic vessels and skin biology. Key highlights include the critical role of stem cell-lymphatic vessel crosstalk in orchestrating skin regeneration, emerging translational approaches, and their implications for skin diseases. Additionally, the review identifies research gaps and proposes potential future directions, underscoring the significance of this rapidly evolving research arena.

The pretreatment of lignocellulosic biomass with acid generates phenolic and furanyl compounds that function as toxins by inhibiting microbial growth and metabolism. Therefore, it is necessary to detoxify acid-pretreated lignocellulosic biomass for better utilization. Among the various detoxification methods that are available, biodetoxification offers advantages that include mild reaction conditions and low energy consumption. In this study, a newly isolated Rhodococcus aetherivorans strain, N1, was found to effectively degrade various lignin-derived aromatic compounds, such as p-coumarate, ferulate, syringaldehyde, furfural, and 5-hydroxymethylfurfural. Furthermore, the metabolic pathway and genes responsible for this degradation were also identified. In addition, the overexpression of a demethylase (DesA) and 3,4-dioxygenase (DesZ) in strain N1 generated a recombinant strain, N1-S, which showed an enhanced ability to degrade syringaldehyde and 80.5% furfural, 50.7% 5-hydroxymethylfurfural, and 71.5% phenolic compounds in corn cob hydrolysate. The resulting detoxified hydrolysate was used directly as a feedstock for succinate production by Escherichia coli suc260. This afforded 35.3 g/l succinate, which was 6.5 times greater than the concentration afforded when nondetoxified hydrolysate was used. Overall, the results of this study demonstrate that strain N1-S is a valuable microbe for the biodetoxification of lignocellulosic biomass.

From the perspective of institutional change of IPO regulation, this paper discusses the relationship between IPO pricing regulation and audit fees in China. This paper finds that the audit fees of IPO companies are higher in the stage of pricing regulation in comparison to the stage of pricing marketization. We also find auditors charge higher audit fees for the private companies than state-owned companies during the IPO pricing regulation period. Furthermore in regions with tighten legislation, IPO audit fees are higher in the IPO pricing regulation period.

Abstract Background 1,3-Propanediol (1,3-PDO) is a platform compound, which has been widely used in food, pharmaceutical and cosmetic industries. Compared with chemical methods, the biological synthesis of 1,3-PDO has shown promising applications owing to its mild conditions and environmental friendliness. However, the biological synthesis of 1,3-PDO still has the problem of low titer and yield due to the shortage of reducing powers. Results In this study, Klebsiella sp. strain YT7 was successfully isolated, which can synthesize 11.30 g/L of 1,3-PDO from glycerol in flasks. The intracellular redox regulation strategy based on the addition of electron mediators can increase the 1,3-PDO titer to 28.01 g/L. Furthermore, a co-culturing system consisting of strain YT7 and Shewanella oneidensis MR-1 was established, which can eliminate the supplementation of exogenous electron mediators and reduce the by-products accumulation. The 1,3-PDO yield reached 0.44 g/g and the final titer reached 62.90 g/L. The increased titer and yield were attributed to the increased redox levels and the consumption of by-products. Conclusions A two-bacterium co-culture system with Klebsiella sp. strain YT7 and S. oneidensis strain MR-1 was established, which realized the substitution of exogenous electron mediators and the reduction of by-product accumulation. Results provided theoretical basis for the high titer of 1,3-PDO production with low by-product concentration.

Familial non-medullary thyroid carcinoma (FNMTC) accounts for 3% to 9% of all thyroid cancer cases, yet its genetic mechanisms remain unknown. Our study aimed to screen and identify novel susceptibility genes for FNMTC. Whole-exome sequencing (WES) was conducted on a confirmed FNMTC pedigree, comprising four affected individuals across two generations. Variants were filtered and analyzed using ExAC and 1000 Genomes Project, with candidate gene pathogenicity predicted using SIFT, PolyPhen, and MutationTaster. Validation was performed through Sanger sequencing in affected pedigree members and sporadic patients (TCGA database) as well as general population data (gnomAD database). Ultimately, we identified the mutant PPP4R3A (NC_000014.8:g.91942196C>T, or NM_001366432.2(NP_001353361.1):p.(Asp409Asn), based on GRCH37) as an FNMTC susceptibility gene. Subsequently, a series of functional experiments were conducted to investigate the impact of PPP4R3A and its Asp409Asn missense variant in thyroid cancer. Our findings demonstrated that wild-type PPP4R3A exerted tumor-suppressive effects via the Akt-mTOR-P70 S6K/4E-BP1 axis. However, overexpression of the PPP4R3A Asp409Asn mutant resulted in loss of tumor-suppressive function, ineffective inhibition of cell invasion, and even promotion of cell proliferation and migration by activating the Akt/mTOR signaling pathway. These results indicated that the missense variant PPP4R3A Asp409Asn is a candidate susceptibility gene for FNMTC, providing new insights into the diagnosis and intervention of FNMTC.

BackgroundHuman adenovirus type 55 (HAdV55) has a re-emerged as pathogen causing an acute respiratory disease presenting as a severe lower respiratory illness that can cause death. To date, there is no HAdV55 vaccine or treatment available for general use.MethodsHerein, a monoclonal antibody specific for HAdV55, mAb 9-8, was isolated from an scFv-phage display library derived from mice immunized with the purified inactived-HAdV55 virions. By using ELISA and a virus micro-neutralization assay, we evaluated the binding and neutralizing activity of mAb 9-8 following humanization. Western blotting analysis and antigen-antibody molecular docking analysis were used to identify the antigenic epitopes that the humanized monoclonal antibody 9-8-h2 recognized. After that, their thermal stability was determined.ResultsMAb 9-8 showed potent neutralization activity against HAdV55. After humanization, the humanized neutralizing monoclonal antibody (9-8-h2) was identified to neutralize HAdV55 infection with an IC50 of 0.6050 nM. The mAb 9-8-h2 recognized HAdV55 and HAdV7 virus particles, but not HAdV4 particles. Although mAb 9-8-h2 could recognize HAdV7, it could not neutralize HAdV7. Furthermore, mAb 9-8-h2 recognized a conformational neutralization epitope of the fiber protein and the crucial amino acid residues (Arg 288, Asp 157, and Asn 200) were identified. MAb 9-8-h2 also showed favorable general physicochemical properties, including good thermostability and pH stability.ConclusionsOverall, mAb 9-8-h2 might be a promising molecule for the prevention and treatment of HAdV55.

Abstract Synthetic biology has boosted the rapid development on using non-methylotrophy as chassis for value added chemicals production from one-carbon feedstocks, such as methanol and formic acid. The one-carbon dissimilation pathway can provide more NADH than monosaccharides including glucose, which is conducive for reductive chemicals production, such as succinic acid. In this study, the one-carbon dissimilation pathway was introduced in E. coli Suc260 to enhance the succinic acid production capability. Through the rational construction of methanol dissimilation pathway, the succinic acid yield was increased from 0.91 to 0.95 g/g with methanol and sodium formate as auxiliary substrates in anaerobic fed-batch fermentation. Furthermore, the metabolic flux of by-product pyruvate was redirected to succinic acid together with the CO2 fixation. Finally, through the immobilization on a specially designed glycosylated membrane, E. coli cells are more resistant to adverse environments, and the final yield of succinic acid was improved to 0.98 g/g. This study proved the feasibility of endowing producers with methanol dissimilation pathway to enhance the production of reductive metabolites. Graphical Abstract

Abstract Background Butyl acetate has shown wide applications in food, cosmetics, medicine, and biofuel sectors. These short-chain fatty acid esters can be produced by either chemical or biological synthetic process with corresponding alcohols and acids. Currently, biosynthesis of short chain fatty acid esters, such as butyl butyrate, through microbial fermentation systems has been achieved; however, few studies regarding biosynthesis of butyl acetate were reported. Results In this study, three proof-of-principle strategies for the one-pot butyl acetate production from glucose through microbial fermentation were designed and evaluated. (1) 7.3 g/L of butyl acetate was synthesized by butanol-producing Clostridium acetobutylicum NJ4 with the supplementation of exogenous acetic acid; (2) With the addition of butanol, 5.76 g/L of butyl acetate can be synthesized by acetate-producing Actinobacillus succinogenes130z (ΔpflA); (3) Microbial co-culture of C. acetobutylicum NJ4 and A. succinogenes130z (ΔpflA) can directly produce 2.2 g/L of butyl acetate from glucose by using microbial co-culture system with the elimination of precursors. Through the further immobilization of A. succinogenes130z (ΔpflA), butyl acetate production was improved to 2.86 g/L. Conclusion Different microbial mono- and co-culture systems for butyl acetate biosynthesis were successfully constructed. These strategies may be extended to the biosynthesis of a wide range of esters, especially to some longer chain ones.

Canine distemper virus (CDV) is classified into the genus Morbillivirus in the family Paramyxoviridae. This virus has a single-stranded genomic RNA with negative polarity. The wild-type CDV genome is generally composed of 15 690 nucleotides. We previously rescued an enhanced green fluorescence protein (eGFP)-tagged recombinant CDV (rCDV-eGFP) using reverse genetics. In this study, the rCDV-eGFP at passage-7 was subjected to 38 serial plaque-to-plaque transfers (or bottleneck passages) and two extra common passages in cells. In theory, the effect of Muller’s ratchet may fix deleterious mutations in a single viral population after consecutive plaque-to-plaque transfers. In order to uncover a mutated landscape of the rCDV-eGFP under the circumstances of bottleneck passages, the passage-47 progeny was collected for the in-depth analysis via next-generation sequencing. The result revealed a total of nine single-nucleotide mutations (SNMs) in the viral antigenome. Out of them, SNMs at nt 1832, 5022, 5536, 5580, 5746, 6913 and 8803 were identified as total single-nucleotide substitution, i.e., 100% of mutation frequency. The result suggested no notable formation of viral quasispecies in the rCDV-eGFP population after consecutive plaque-to-plaque transfers.

Vanillin has been widely used as a flavoring agent in the food industry and as a precursor in the medicine and polymer industries. However, the use of chemically synthesized vanillin is prohibited in food and some other industries. Additionally, the harsh conditions and toxic substrates in chemically synthesized vanillin lead to some environmental challenges and energy waste. With the rapid development of synthetic biology, the biological production of vanillin from renewable resources through microbial fermentation has gained great attention owing to its high selectivity and environmentally friendly properties. Accordingly, this article will discuss the vanillin biosynthesis technology from the aspects of chassis cell types and substrate types. The key enzymes involved in metabolic pathways are also discussed. Then, we summarize some improvements in the process of vanillin production to increase its production and reduce the toxicity of vanillin in microorganisms, and the possible future directions for vanillin biosynthesis will also be outlined.

Abstract Clostridium sp. strain CT7 is a new emerging microbial cell factory with high butanol production ratio owing to its non-traditional butanol fermentation mode with uncoupled acetone and 1,3-propanediol formation. Significant changes of metabolic products profile were shown in glycerol- and glucose-fed strain CT7, especially higher butanol and lower volatile fatty acids (VFAs) production occurred from glycerol-fed one. However, the mechanism of this interesting phenomenon was still unclear. To better elaborate the bacterial response towards glycerol and glucose, the quantitative proteomic analysis through iTRAQ strategy was performed to reveal the regulated proteomic expression levels under different substrates. Proteomics data showed that proteomic expression levels related with carbon metabolism and solvent generation under glycerol media were highly increased. In addition, the up-regulation of hydrogenases, ferredoxins and electron-transferring proteins may attribute to the internal redox balance, while the earlier triggered sporulation response in glycerol-fed media may be associated with the higher butanol production. This study will pave the way for metabolic engineering of other industrial microorganisms to obtain efficient butanol production from glycerol.

Abstract Spatial transcriptomics is considered as an important part of spatiotemporal molecular images to bridge molecular information with clinical images. Of those potentials and opportunities, the excellent quality of human sample preparation and handling will ensure the precise and reliable information generated from clinical spatial transcriptome. The present study aims at defining potential factors that might influence the quality of spatial transcriptomics in lung cancer, para‐cancer, or normal tissues, pathological images of sections and the RNA integrity before spatial transcriptome sequencing. We categorised potential influencing factors from clinical aspects, including patient selection, pathological definition, surgical types, sample harvest, temporary preservation conditions and solutions, frozen approaches, transport and storage conditions and duration. We emphasis on the relationship between the combination of histological scores with RNA integrity number (RIN) and the unique molecular identifier (UMI), which is determines the quality of of spatial transcriptomics; however, we did not find significantly relevance between them. Our results showed that isolated times and dry conditions of sample are critical for the UMI and the quality of spatial transcriptomic samples. Thus, clinical procedures of sample preparation should be furthermore optimised and standardised as new standards of operation performance for clinical spatial transcriptome. Our data suggested that the temporary preservation time and condition of samples at operation room should be within 30 min and in ‘dry’ status. The direct cryo‐preservation within OCT media for human lung sample is recommended. Thus, we believe that clinical spatial transcriptome will be a decisive approach and bridge in the development of spatiotemporal molecular images and provide new insights for understanding molecular mechanisms of diseases at multi‐orientations.

At present, research in the field of college students' entrepreneurship has proliferated, but these studies tend to analyze the net benefits of various factors on entrepreneurial activities, which are affected by the configuration effects of multiple factors; hence, it remains unclear whether entrepreneurial education can make graduates more efficient to started their own companies. To fill this gap in the literature, drawing on general systems theory and using fuzzy-set qualitative comparative analysis (fsQCA), we take 1,87,914 undergraduate and junior college students from 1,231 colleges and universities in China as a sample to explore the relationships among the five conditions in the entrepreneurship education environment and cognitive level (i.e., the quality of staff, subject curriculum, entrepreneurial competition, intentions, and opportunity identifications) and entrepreneurial activities. The fsQCA results show that none of these factors are sufficient for entrepreneurial activity. In contrast, three combinations of the five conditions (i.e., co-creation type, competition-oriented environment, and entrepreneurship education that fits under the guidance of entrepreneurial intention) can produce high entrepreneurial activity, as well as substitution and complementarity among the various elements within the configuration. These results show that the combined effect of the five conditions is more conducive to the entrepreneurial activities of college students. Finally, after a discussion of the study's findings, theoretical, and practical contributions are analyzed with regard to the field of entrepreneurship in Chinese colleges, and alternative options indicate that college students are more likely to become entrepreneurs in the future.

Abstract Microbial communities are ubiquitous in nature and exhibit several attractive features, such as sophisticated metabolic capabilities and strong environment robustness. Inspired by the advantages of natural microbial consortia, diverse artificial co-cultivation systems have been metabolically constructed for biofuels, chemicals and natural products production. In these co-cultivation systems, especially genetic engineering ones can reduce the metabolic burden caused by the complex of metabolic pathway through labor division, and improve the target product production significantly. This review summarized the most up-to-dated co-cultivation systems used for biofuels, chemicals and nature products production. In addition, major challenges associated with co-cultivation systems are also presented and discussed for meeting further industrial demands.

Abstract Background Cyclodextrin glucanotransferase (CGTase) can transform L-ascorbic acid (L-AA, vitamin C) to 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G), which shows diverse applications in food, cosmetic and pharmaceutical industries. Results In this study, the cgt gene encoding α-CGTase from Paenibacillus macerans was codon-optimized (opt-cgt) and cloned into pET-28a (+) for intracellular expression in E. coli BL21 (DE3). The Opt-CGT was purified by Ni2+-NTA resin with a 55% recovery, and specific activity was increased significantly from 1.17 to 190.75 U·mg− 1. In addition, the enzyme was adopted to transform L-AA into 9.1 g/L of AA-2G. Finally, more economic substrates, including β-cyclodextrin, soluble starch, corn starch and cassava starch could also be used as glycosyl donors, and 4.9, 3.5, 1.3 and 1.5 g/L of AA-2G were obtained, respectively. Conclusions N-terminal amino acid is critical to the activity of CGTase suggested by its truncation study. Furthermore, when the Opt-CGT was flanked by His6-tags on the C- and N-terminal, the recovery of purification by Ni2+-NTA resin is appreciably enhanced. α-cyclodextrin was the ideal glycosyl donor for AA-2G production. In addition, the selection of low cost glycosyl donors would make the process of AA-2G production more economically competitive.

Abstract Background Consolidated bioprocessing (CBP) has attracted increasing attention since it can accomplish hydrolytic enzymes production, lignocellulose degradation and microbial fermentation in one single step. Currently, biobutanol is mainly produced by mesophilic and solventogenic clostridia, such as Clostridium beijerinckii and C. acetobutylicum, which cannot directly utilize lignocellulose, an abundant, renewable and economic feedstock. Hence, metabolic construction or isolation of novel cellulolytic/hemicellulolytic and solventogenic bacteria to achieve direct butanol production from lignocellulose offers a promising alternative. Results In this study, a newly isolated Thermoanaerobacterium sp. M5 could directly produce butanol from xylan through CBP at 55 °C via the butanol–ethanol pathway. Further genomic and proteomic analysis showed that the capabilities of efficient xylan degradation and butanol synthesis were attributed to the efficient expression of xylanase, β-xylosidase and the bifunctional alcohol/aldehyde dehydrogenase (AdhE). Process optimization based on the characteristic of AdhE could further improve the final butanol titer to 1.17 g/L from xylan through CBP. Furthermore, a new co-cultivation system consisting of Thermoanaerobacterium sp. M5 which could release xylose from xylan efficiently and C. acetobutylicum NJ4 which possesses the capacity of high butanol production was established. This microbial co-cultivation system could improve the butanol titer to 8.34 g/L, representing the highest butanol titer from xylan through CBP. Conclusions A newly thermophilic and butanogenic bacterium Thermoanaerobacterium sp. M5 was isolated and key enzymes responsible for butanol production were characterized in this study. High butanol titer was obtained from xylan through process optimization. In addition, the newly set up microbial co-cultivation system, consisting of Thermoanaerobacterium sp. M5 and C. acetobutylicum NJ4, achieved the highest butanol production from xylan compared with the reported co-cultivation systems.

Lignocellulose is a kind of renewable bioresource containing abundant polysaccharides, which can be used for biochemicals and biofuels production. However, the complex structure hinders the final efficiency of lignocellulosic biorefinery. This review comprehensively summarizes the hydrolases and typical microorganisms for lignocellulosic degradation. Moreover, the commonly used bioprocesses for lignocellulosic biorefinery are also discussed, including separated hydrolysis and fermentation, simultaneous saccharification and fermentation and consolidated bioprocessing. Among these methods, construction of microbial co-culturing systems via consolidated bioprocessing is regarded as a potential strategy to efficiently produce biochemicals and biofuels, providing theoretical direction for constructing efficient and stable biorefinery process system in the future.

Fingerprint recognition schemas are widely used in our daily life, such as Door Security, Identification, and Phone Verification. However, the existing problem is that fingerprint recognition systems are easily tricked by fake fingerprints for collaboration. Therefore, designing a fingerprint liveness detection module in fingerprint recognition systems is necessary. To solve the above problem and discriminate true fingerprint from fake ones, a novel software-based liveness detection approach using uniform local binary pattern (ULBP) in spatial pyramid is applied to recognize fingerprint liveness in this paper. Firstly, preprocessing operation for each fingerprint is necessary. Then, to solve image rotation and scale invariance, three-layer spatial pyramids of fingerprints are introduced in this paper. Next, texture information for three layers spatial pyramids is described by using uniform local binary pattern to extract features of given fingerprints. The accuracy of our proposed method has been compared with several state-of-the-art methods in fingerprint liveness detection. Experiments based on standard databases, taken from Liveness Detection Competition 2013 composed of four different fingerprint sensors, have been carried out. Finally, classifier model based on extracted features is trained using SVM classifier. Experimental results present that our proposed method can achieve high recognition accuracy compared with other methods.

RN and SSR approaches are designed to detect NLOS propagation paths in this paper. When the NLOS propagation paths are detected, an estimation approach for the NLOS range errors is proposed by using residual-error decomposition. The approach can estimate the NLOS range errors quickly and effectively, even if there are multiple NLOS propagation paths. Combining the movement equation with observation position, the position of mobile target node can be tracked precisely with Kalman filter algorithm. Using the estimated NLOS range errors, we correct the localization result and modify Kalman filter to mitigate the NLOS propagations. The simulations demonstrate the validity with RN and SSR detection methods and analyze the impacts of NLOS range errors and number of NLOS anchor nodes. The estimated NLOS range errors are proved to be close to the true especially when the NLOS range errors are much bigger than LOS range errors. The simulation results show that the position of target node can be tracked precisely and effectively, when the NLOS mitigation is used to track the target node position with modified Kalman filter.

Wireless sensor networks for environment monitoring are usually deployed in the fields where electric or manual intervention cannot be accessed easily. Therefore, we hope to minimize the times of sampling to reduce energy consuming. Energy-efficient sampling scheduling can be realized using compressive sensing theory on the basis of temporal correlation of the physical process. However, the degree of correlation of neighboring data varies over time, which may lead to different reconstructive quality for different parts of data if constant duty cycle is used. We proposed SDDC, a segmental dynamic duty cycle control method, for sampling scheduling in wireless sensor networks based on compressive sensing. Using a priori knowledge obtained by means of analysis on earlier sensing data, dynamic duty cycle is determined according to the linear degree of data in each segment. The experimental results using data from soil respiration monitoring sensor networks show that the proposed SDDC method can lead to better reconstructive quality compared to constant duty cycle of the same average sampling rate. That is to say, the SDDC method needs smaller sampling rate if the reconstructive error threshold is given and consequently saves more energy.