Publications by authors named "Xing Guo"

268 Publications

Unprecedented Electrochromic Stability of a-WO Thin Films Achieved by Using a Hybrid-Cationic Electrolyte.

ACS Appl Mater Interfaces 2021 Mar 1. Epub 2021 Mar 1.

Division of Solid-State Electronics, Ågströmlaboratoriet, Uppsala University, Sweden 75121, Uppsala.

With large interstitial space volumes and fast ion diffusion pathways, amorphous metal oxides as cathodic intercalation materials for electrochromic devices have attracted attention. However, these incompact thin films normally suffer from two inevitable imperfections: self-deintercalation of guest ions and poor stability of the structure, which constitute a big obstacle toward the development of high-stable commercial applications. Here, we present a low-cost, eco-friendly hybrid cation 1,2-PG-AlCl·6HO electrolyte, in which the sputter-deposited a-WO thin film can exhibit both the long-desired excellent open-circuit memory (>100 h, with zero optical loss) and super-long cycling lifetime (∼20,000 cycles, with 80% optical modulation), benefiting from the formation of unique Al-hydroxide-based solid electrolyte interphase during electrochromic operations. In addition, the optical absorption behaviors in a-WO caused by host-guest interactions were elaborated. We demonstrated that the intervalence transfers are primarily via the "corner-sharing" related path (W ↔ W) but not the "edge-sharing" related paths (W ↔ W and/or W ↔ W), and the small polaron/electron transfers taking place at the W-O bond-breaking positions are not allowed. Our findings might provide in-depth insights into the nature of electrochromism and provide a significant step in the realization of more stable, more excellent electrochromic applications based on amorphous metal oxides.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.0c22921DOI Listing
March 2021

The genome of Magnolia biondii Pamp. provides insights into the evolution of Magnoliales and biosynthesis of terpenoids.

Hortic Res 2021 Mar 1;8(1):38. Epub 2021 Mar 1.

Laboratory of Southern Subtropical Plant Diversity, Fairy Lake Botanical Garden, Shenzhen & Chinese Academy of Sciences, Shenzhen, 518004, China.

Magnolia biondii Pamp. (Magnoliaceae, magnoliids) is a phylogenetically, economically, and medicinally important ornamental tree species widely grown and cultivated in the north-temperate regions of China. Determining the genome sequence of M. biondii would help resolve the phylogenetic uncertainty of magnoliids and improve the understanding of individual trait evolution within the Magnolia genus. We assembled a chromosome-level reference genome of M. biondii using ~67, ~175, and ~154 Gb of raw DNA sequences generated via Pacific Biosciences single-molecule real-time sequencing, 10X Genomics Chromium, and Hi-C scaffolding strategies, respectively. The final genome assembly was ~2.22 Gb, with a contig N50 value of 269.11 kb and a BUSCO complete gene percentage of 91.90%. Approximately 89.17% of the genome was organized into 19 chromosomes, resulting in a scaffold N50 of 92.86 Mb. The genome contained 47,547 protein-coding genes, accounting for 23.47% of the genome length, whereas 66.48% of the genome length consisted of repetitive elements. We confirmed a WGD event that occurred very close to the time of the split between the Magnoliales and Laurales. Functional enrichment of the Magnolia-specific and expanded gene families highlighted genes involved in the biosynthesis of secondary metabolites, plant-pathogen interactions, and responses to stimuli, which may improve the ecological fitness and biological adaptability of the lineage. Phylogenomic analyses revealed a sister relationship of magnoliids and Chloranthaceae, which are sister to a clade comprising monocots and eudicots. The genome sequence of M. biondii could lead to trait improvement, germplasm conservation, and evolutionary studies on the rapid radiation of early angiosperms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41438-021-00471-9DOI Listing
March 2021

Long Noncoding RNA ANPODRT Overexpression Protects Nucleus Pulposus Cells from Oxidative Stress and Apoptosis by Activating Keap1-Nrf2 Signaling.

Oxid Med Cell Longev 2021 2;2021:6645005. Epub 2021 Feb 2.

Department of Orthopedics, Tianjin Medical University General Hospital, Tianjin 300052, China.

Oxidative stress and subsequent nucleus pulposus (NP) cell apoptosis are important contributors to the development of intervertebral disc degeneration (IDD). Emerging evidences show that long noncoding RNAs (lncRNAs) play a role in the pathogenesis of IDD. In this study, we investigated the role of lncRNA ANPODRT (anti-NP cell oxidative damage-related transcript) in oxidative stress and apoptosis in human NP cells. We found that ANPODRT was downregulated in degenerative NP tissues and in NP cells treated with tert-butyl hydroperoxide (TBHP, the oxidative stress inducer). ANPODRT overexpression alleviated oxidative stress and apoptosis in NP cells exposed to TBHP, while ANPODRT knockdown exerted opposing effects. Mechanistically, ANPODRT facilitated nuclear factor E2-related factor 2 (Nrf2) accumulation and nuclear translocation and activated its target genes by disrupting the kelch-like ECH-associated protein 1- (Keap1-) Nrf2 association in NP cells. Nrf2 knockdown abolished the antioxidative stress and antiapoptotic effects of ANPODRT in NP cells treated with TBHP. Collectively, our findings suggest that ANPODRT protects NP cells from oxidative stress and apoptosis, at least partially, by activating Nrf2 signaling, implying that ANPODRT may be a potential therapeutic target for IDD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2021/6645005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7872767PMC
February 2021

Proteasome regulation by reversible tyrosine phosphorylation at the membrane.

Oncogene 2021 Feb 18. Epub 2021 Feb 18.

Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China.

Reversible phosphorylation has emerged as an important mechanism for regulating 26S proteasome function in health and disease. Over 100 phospho-tyrosine sites of the human proteasome have been detected, and yet their function and regulation remain poorly understood. Here we show that the 19S subunit Rpt2 is phosphorylated at Tyr439, a strictly conserved residue within the C-terminal HbYX motif of Rpt2 that is essential for 26S proteasome assembly. Unexpectedly, we found that Y439 phosphorylation depends on Rpt2 membrane localization mediated by its N-myristoylation. Multiple receptors tyrosine kinases can trigger Rpt2-Y439 phosphorylation by activating Src, a N-myristoylated tyrosine kinase. Src directly phosphorylates Rpt2-Y439 in vitro and negatively regulates 26S proteasome activity at cellular membranes, which can be reversed by the membrane-associated isoform of protein tyrosine phosphatase nonreceptor type 2 (PTPN2). In H1975 lung cancer cells with activated Src, blocking Rpt2-Y439 phosphorylation by the Y439F mutation conferred partial resistance to the Src inhibitor saracatinib both in vitro and in a mouse xenograft tumor model, and caused significant changes of cellular responses to saracatinib at the proteome level. Our study has defined a novel mechanism involved in the spatial regulation of proteasome function and provided new insights into tyrosine kinase inhibitor-based anticancer therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41388-021-01674-zDOI Listing
February 2021

Structural Insights into the -Acting Enoyl Reductase in the Biosynthesis of Long-Chain Polyunsaturated Fatty Acids in .

J Agric Food Chem 2021 Feb 15;69(7):2316-2324. Epub 2021 Feb 15.

Engineering Research Center of Industrial Microbiology, Ministry of Education; Collaborative Innovation Center of Haixi Green Bio-Manufacturing Technology, Ministry of Education; National & Local Joint Engineering Research Center of Industrial Microbiology and Fermentation Technology, National Development and Reform Commission; College of Life Sciences, Fujian Normal University, Fuzhou, 350117, P. R. China.

Two long-chain polyunsaturated fatty acids (LC-PUFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), play vital roles in human health. Similarly, two biosynthetic pathways, based on desaturase/elongase and polyketide synthase, have been implicated in the synthesis of microbial LC-PUFA. Up to now, only several microalgae, no bacteria, have been used in the commercial production of oils rich in DHA and/or EPA. Fully understanding the enzymatic mechanism in the biosynthesis of LC-PUFA would contribute significantly to produce EPA and/or DHA by the bacteria. In this study, we report a 1.998 Å-resolution crystal structure of -acting enoyl reductase (ER), SpPfaD, from . The SpPfaD model consists of one homodimer in the asymmetric unit, and each subunit contains three domains. These include an N-terminal, a central domain forming a classic TIM barrel with a single FMN cofactor molecule bound atop the barrel, and a C-terminal domain with a lid above the TIM barrel. Furthermore, we docked oxidized nicotinamide adenine dinucleotide phosphate (NADP) and an inhibitor 2-(4-(2-((3-(5-(pyridin-2-ylthio)thiazol-2-yl)ureido)methyl)-1-imidazole-4-yl)phenoxy)acetic acid (TUI) molecule into the active site and analyzed the inhibition and catalytic mechanisms of the enoyl reductase SpPfaD. To the best of our knowledge, this is the first crystal structure of -ER in the biosynthesis of bacterial polyketides.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jafc.0c07386DOI Listing
February 2021

Organocatalytic enantioselective [2 + 4]-annulation of γ-substituted allenoates with -acyldiazenes for the synthesis of optically active 1,3,4-oxadiazines.

Org Biomol Chem 2021 Feb 4. Epub 2021 Feb 4.

Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, College of Science, Southern University of Science and Technology, Shenzhen 518055, China.

An enantioselective [2 + 4]-annulation of γ-substituted allenoates with N-acyldiazenes has been developed for the first time. In the presence of an l-proline-derived DMAP analogue, the annulation proceeded smoothly to afford a broad range of 1,3,4-oxadiazine derivatives in good to excellent yields with high stereoselectivities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0ob02508aDOI Listing
February 2021

MicroRNA-29a-3p delivery via exosomes derived from engineered human mesenchymal stem cells exerts tumour suppressive effects by inhibiting migration and vasculogenic mimicry in glioma.

Aging (Albany NY) 2021 Feb 1;12. Epub 2021 Feb 1.

Department of Neurosurgery, Qilu Hospital, Cheeloo College of Medicine and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan 250012, Shandong, China.

Vasculogenic mimicry (VM), the formation of an alternative microvascular circulation independent of VEGF-driven angiogenesis, is reluctant to anti-angiogenesis therapy for glioma patients. However, treatments targeting VM are lacking due to the poor understanding of the molecular mechanism involved in VM formation. By analysing the TCGA database, microRNA-29a-3p (miR-29a-3p) was found to be highly expressed in normal brain tissue compared with glioma. An study revealed an inhibitory role for miR-29a-3p in glioma cell migration and VM formation, and further study confirmed that ROBO1 is a direct target of miR-29a-3p. Based on this, we engineered human mesenchymal stem cells (MSCs) to produce miR-29a-3p-overexpressing exosomes. Treatment with these exosomes attenuated migration and VM formation in glioma cells. Moreover, the anti-glioma role of miR-29a-3p and miR-29a-3p-overexpressing exosomes were confirmed . Overall, the present study demonstrates that MSCs can be used to produce miR-29a-3p-overexpressing exosomes, which have great potential for anti-VM therapy and may act as supplements to anti-angiogenetic therapy in the clinic.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/aging.202424DOI Listing
February 2021

Exercise profile and effect on growth traits, carcass yield, meat quality, and tibial strength in Chinese Wannan chickens.

Poult Sci 2021 Feb 28;100(2):721-727. Epub 2020 Nov 28.

College of Animal Science and Technology, Anhui Agricultural University, Hefei, China. Electronic address:

The aim of the study was to understand the dynamic changes in daily step counts (DSC) during the development of chickens and to further explore the effects of exercise on the growth performance, carcass yield, meat quality, and tibial strength of cocks. A total of 600 (half male and half female) 1-day-old Wannan chickens with similar hatching weights were raised under the same rearing conditions. All birds were wing banded and housed in identical cages for from 1 to 8 wk in the experimental poultry house. The dimensions of the cages were 70 × 70 × 40 cm (length × width × height). At the age of 9 to 16 wk, these birds were reared in indoor pens (2 m × 2 m, 1,000 cm per bird). In addition, they also had a free-range grass paddock (20 m × 30 m, 1 m per bird). The DSC of male and female Wannan chicks were recorded from 70 to 112 d by using a pedometer. At 112 d of age, based on the average DSC, birds were divided into groups representing the highest (HS), medium, and lowest (LS) number of step groups. Fifteen cocks from each group were selected for subsequent experiments. Compared with the LS group, the HS group displayed higher tibial strength (P = 0.025) and lower BW, cooking loss (P = 0.014), shear force (P = 0.023), and drip loss (P = 0.008). The DSC had no effects on the female BW or male carcass parameters. There was no significant change in the DSC of all birds from 70 to 112 d. However, male chickens took more steps than females at 15 (P = 0.025) and 16 (P = 0.012) week of age. In conclusion, the effects of the DSC on the BW of Wannan chickens depend on sex, and enhanced exercise could improve the meat quality and tibial strength of cocks.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.psj.2020.11.044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7858180PMC
February 2021

Direct C-H alkoxylation of BODIPY dyes via cation radical accelerated oxidative nucleophilic hydrogen substitution: a new route to building blocks for functionalized BODIPYs.

Chem Commun (Camb) 2021 Feb 19;57(13):1647-1650. Epub 2021 Jan 19.

Key Laboratory of Functional Molecular Solids, Ministry of Education, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, 241002, China.

Oxidative nucleophilic α-hydrogen substitution is a direct method for BODIPY functionalization. However, it was hampered by the low reactivity of BODIPYs toward weak nucleophiles. Herein, we develop a cation radical accelerated oxidative nucleophilic α-hydrogen substitution reaction between BODIPY dyes and a variety of alcohols. This direct C-H alkoxylation presented a wide substrate scope and high site selectivity, providing a series of α-alkoxylated BODIPYs with diverse functional groups. Moreover, a BODIPY derivative with a pyridinium ion was developed as a new mitochondria-targeting fluorescent probe with favorable photophysical properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0cc07961hDOI Listing
February 2021

A near-infrared light-responsive extracellular vesicle as a "Trojan horse" for tumor deep penetration and imaging-guided therapy.

Biomaterials 2021 Feb 2;269:120647. Epub 2021 Jan 2.

Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, PR China. Electronic address:

How to make the nanoparticles evade immune surveillance and deeply penetrate the tumor tissues is of great importance to maximize the therapeutic efficacy of nanomedicines. Here, a near-infrared (NIR) light-responsive extracellular vesicle as a nanoplatform is developed to realize long circulation in blood, deep penetration in tumor tissues and rapid body elimination after the treatment. Like a "Trojan horse", the nanoplatform is obtained by hiding the anti-tumor soldiers (DOX and 4.2 nm AgS quantum dots (QDs)) into the macrophage cell-secreted vesicle through electroporation. The natural composition and tumor targeting activity of the extracellular vesicles enable the nanoplatform to achieve a high accumulation in tumor and the in vivo biodistribution can be monitored by NIR fluorescence imaging of the AgS QDs. After the nanomedicines accumulate at the tumor sites, the soldiers will be released from the "Trojan horse" by utilizing the NIR photothermal effect of the AgS QDs. The released ultrasmall QDs and DOX can penetrate the whole tumor with a diameter of about 9 mm and effectively kill the tumor cells. Moreover, the inorganic QDs can be rapidly excreted from the body through renal clearance after the treatment to avoid the potential toxicity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.biomaterials.2020.120647DOI Listing
February 2021

Wrist tuberculosis-experience from eighteen cases: a retrospective study.

J Orthop Surg Res 2021 Jan 9;16(1):37. Epub 2021 Jan 9.

Department of Orthopedic Surgery, The Affiliated Hospital of Southwest Medical University, No. 25 Taiping Road, Luzhou, 646000, Sichuan, People's Republic of China.

Background: Wrist tuberculosis is a rare disease, which is easy to be misdiagnosed, leading to delayed treatment and poor prognosis. In this study, the clinical manifestations, diagnosis, treatment, and prognosis of 18 cases of wrist tuberculosis were analyzed retrospectively.

Methods: A retrospective study was conducted, investigating tuberculosis of the wrist, diagnosed in 18 patients from August 2013 to November 2018. Puncture biopsy confirmed the diagnosis. The study includes 11 males and 7 females, and 8 left and 10 right wrists. The average age was 53.5 ± 18.3 years and ranged from 15 to 81 years. The disease course was 1 to 42 months, with an average of 15.1 ± 11.3 months. Eighteen patients were underwent surgery and chemotherapy, 3 patients with severe bone defects were treated with wrist fusion, and 15 patients were underwent focus removal. The Gartland and Werley score, DASH score, the range of motion (ROM), grip strength, and imaging examinations were used to evaluate the postoperative recovery of the patients.

Results: Eighteen patients were followed up for 15 to 77 months, with an average follow up of 39.7 ± 15.3 months. The ESR and CRP levels were normal for all patients after chemotherapy. No recurrence of tuberculosis was observed in any of the patients. Among the 15 focus removals, the Gartland and Werley scores at admission, two weeks of chemotherapy, 1 month after surgery, and the last follow-up were 21.73 ± 4.33, 18.60 ± 3.16,11.27 ± 2.79, and 5.07 ± 2.28, respectively; and the DASH scores were 45.87 ± 5.58, 39.47 ± 4.72, 22.67 ± 6.54, and 6.73 ± 2.94, respectively. The range of motion (ROM) of the wrist and grip strength improved significantly when compared to those at admission. Among the three cases of wrist fusion, 2 were fixed with a steel plate and the fixation position of wrist joint was good. One case was fixed with Kirschner wire and resulted in a slightly deformed wrist joint.

Conclusion: For patients with wrist tuberculosis, early diagnosis, preoperative and postoperative chemotherapy, thorough focus removal, and appropriate fixation of the affected limb can help restore the function of the affected wrist, reduce the recurrence rate, and improve the quality of life.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13018-020-02198-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7797126PMC
January 2021

Cell surface GRP78 regulates BACE2 via lysosome-dependent manner to maintain mesenchymal phenotype of glioma stem cells.

J Exp Clin Cancer Res 2021 Jan 7;40(1):20. Epub 2021 Jan 7.

Department of Neurosurgery, Qilu Hospital, Cheeloo College of Medicine and Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, Shandong, China.

Background: Glioma stem cells (GSCs) are considered the initial cells of gliomas, contributing to therapeutic resistance. Patient-derived GSCs well recapitulate the heterogeneity of their parent glioma tissues, which can be classified into different subtypes. Likewise, previous works identified GSCs as two distinct subtypes, mesenchymal (MES) and proneural (PN) subtypes, and with general recognition, the MES subtype is considered a more malignant phenotype characterized by high invasion and radioresistance. Therefore, understanding the mechanisms involved in the MES phenotype is necessary for glioblastoma treatment.

Methods: Data for bioinformatic analysis were obtained from The Cancer Genome Atlas (TCGA) and The Gene Expression Omnibus (GEO) database. An antibody was used to block cell surface glucose-regulated protein 78 (csGRP78). Apoptosis and cell cycle analyses were performed to evaluate radiation damage. Immunofluorescence staining was applied to assess protein expression and distribution. Mass spectrometry combined with bioinformatic analysis was used to screen downstream molecules. Intracranial GSC-derived xenografts were established for in vivo experiments.

Results: Total GRP78 expression was associated with MES GSC stemness, and csGRP78 was highly expressed in MES GSCs. Targeting csGRP78 suppressed the self-renewal and radioresistance of MES GSCs in vitro and in vivo, accompanied by downregulation of the STAT3, NF-κB and C/EBPβ pathways. Mass spectrometry revealed the potential downstream β-site APP-cleaving enzyme 2 (BACE2), which was regulated by csGRP78 via lysosomal degradation. Knockdown of BACE2 inactivated NF-κB and C/EBPβ and significantly suppressed the tumorigenesis and radioresistance of MES GSCs in vitro and in vivo.

Conclusions: Cell surface GRP78 was preferentially expressed in MES GSCs and played a pivotal role in MES phenotype maintenance. Thus, blocking csGRP78 in MES GSCs with a high-specificity antibody might be a promising novel therapeutic strategy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13046-020-01807-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7791784PMC
January 2021

Revisiting the evolutionary history of domestic and wild ducks based on genomic analyses.

Zool Res 2021 Jan;42(1):43-50

Anhui Province Key Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Bio-breeding, Anhui Agricultural University, Hefei, Anhui 230036, China.

Although domestic ducks have been important poultry species throughout human history, their origin remains enigmatic, with mallards and/or Chinese spot-billed ducks being proposed as the direct wild ancestor(s) of domestic ducks. Here, we analyzed 118 whole genomes from mallard, Chinese spot-billed, and domestic ducks to reconstruct their evolutionary history. We found pervasive introgression patterns among these duck populations. Furthermore, we showed that domestic ducks separated from mallard and Chinese spot-billed ducks nearly 38 thousand years ago (kya) and 54 kya, respectively, which is considerably outside the time period of presumed duck domestication. Thus, our results suggest that domestic ducks may have originated from another wild duck population that is currently undefined or unsampled, rather than from present-day mallard and/or Chinese spot-billed ducks, as previously thought. Overall, this study provides new insight into the complex evolution of ducks.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.24272/j.issn.2095-8137.2020.133DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7840458PMC
January 2021

Effects of plastic antipecking devices on the production performance, beak length, and behavior in Chinese Wannan chickens.

Poult Sci 2020 Dec 18;99(12):6715-6722. Epub 2020 Sep 18.

College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui 230036, China. Electronic address:

This study examined the effects of plastic antipecking devices (PAD) on the production performance, upper beak length, behavior, and plumage condition of a local Chinese chicken breed. Three hundred sixty 63-d-old Wannan chickens with intact beaks were randomly allocated into 3 groups. Birds were fitted with the PAD at 63 d (PAD63d) and at 77 d of age (PAD77d). Control birds were not fitted with PAD. The results showed that there were no significant effects of PAD on the BW, carcass traits, and meat quality (P > 0.05). The mortality in the PAD63d and PAD77d groups was lower than that in the control group. Compared with those in the PAD77d and control groups, the feed conversion ratio (FCR) from 63 to 112 d of age was lower in the PAD63d group. The ADFI of birds from 63 to 112 d of age was lowest in birds in the PAD63d group, intermediate in birds in the PAD77d group, and highest in control birds (P < 0.05). Birds in the PAD63d and PAD77d groups showed a lower frequency of walking and running, a higher frequency of sleeping, and higher plumage scores of the back and tail than those of control birds (P < 0.05). Birds' daily walking steps in the PAD77d group decreased compared with that of birds in the control group (P < 0.05). The upper beak length at 91 d and 112 d of age was longest in birds in the PAD63d group and shortest in control birds (P < 0.05). Overall, PAD appeared to be effective at reducing mortality, FCR, overall activity, and plumage damage and increasing the upper beak length.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.psj.2020.09.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7704998PMC
December 2020

Direct sulfonylation of BODIPY dyes with sodium sulfinates through oxidative radical hydrogen substitution at the α-position.

Chem Commun (Camb) 2020 Dec 27;56(99):15577-15580. Epub 2020 Nov 27.

The Key Laboratory of Functional Molecular Solids, Ministry of Education, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, China.

An efficient and convenient protocol for the direct sulfonylation of BODIPY dyes with sodium sulfinates via a radical process is described for the first time. This transformation presented wide substrate scope and high regioselectivity, providing a series of α-sulfonylated BODIPYs. Meaningfully, the sulfonyl group, as a good leaving group, allowed the facile introduction of a variety of functionalities on the BODIPY core. Moreover, a 2,4-dinitrobenzenesulfonyl (DBS) group substituted BODIPY showed dramatically quenched fluorescence via the photoinduced electron transfer (PET) pathway, and was demonstrated as a new fluorescent probe for selective biothiol detection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0cc07259aDOI Listing
December 2020

G-CSF shifts erythropoiesis from bone marrow into spleen in the setting of systemic inflammation.

Life Sci Alliance 2021 01 24;4(1). Epub 2020 Nov 24.

Department of Pharmacology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China

The anemia of inflammation is related in part to abnormal erythropoiesis in bone marrow. G-CSF regulates granulopoiesis and is increased during systemic inflammation. Here, we have showed that high levels of G-CSF are associated with repression of bone marrow erythropoiesis and expansion of splenic erythropoiesis in -infected mice and lipopolysaccharide-treated mice. Under lipopolysaccharide-induced systemic inflammatory conditions in mice, G-CSF neutralization with antibody alleviated the blockage of bone marrow erythropoiesis, prevented the enhancement of splenic erythropoiesis, ameliorated splenomegaly, and reduced the brittleness of spleen. We further demonstrated that after lipopolysaccharide treatment, -knockout mice display low levels of G-CSF, healthy bone marrow erythropoiesis, almost no stress erythropoiesis in the spleen, and normal size and toughness of spleen. In addition, we found HIF-mediated erythropoietin production is essential for splenic erythropoiesis in the setting of G-CSF-induced suppression of bone marrow erythropoiesis. Our findings identify G-CSF as a critical mediator of inflammation-associated erythropoiesis dysfunction in bone marrow and offer insight into the mechanism of G-CSF-induced splenic erythropoiesis. We provide experimentally significant dimension to the biology of G-CSF.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.26508/lsa.202000737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7723243PMC
January 2021

Conformationally Restricted α, α Directly Linked BisBODIPYs as Highly Fluorescent Near-Infrared Absorbing Dyes.

Org Lett 2020 12 23;22(23):9239-9243. Epub 2020 Nov 23.

Key Laboratory of Functional Molecular Solids, Ministry of Education, School of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China.

A new family of α, α directly linked bisBODIPYs was developed through a MoCl-mediated intramolecular oxidative reaction. Due to the coplanar structure of the two conformationally locked BODIPY units, these bisBODIPYs showed well-extended conjugations and gave strong near-infrared absorptions and emissions with maxima around 760 and 780 nm, respectively, with high fluorescence quantum yields of ≤0.84. These dyes were successfully applied for and fluorescence imaging by taking advantage of their beneficial photophysical properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.orglett.0c03441DOI Listing
December 2020

A small natural molecule CADPE kills residual colorectal cancer cells by inhibiting key transcription factors and translation initiation factors.

Cell Death Dis 2020 11 15;11(11):982. Epub 2020 Nov 15.

College of Pharmaceutical Sciences, Zhejiang University, 310058, Hangzhou, Zhejiang, China.

Residual disease is the major cause for colorectal cancer (CRC) relapse. Herein, we explore whether and how a natural molecule CADPE killed heterogenic populations in a panel of CRC cell lines with KRAS/BRAF mutations that are natively resistant to EGFR- or VEGFR-targeted therapy, without sparing persistent cells, a reservoir of the disease relapse. Results showed that CADPE killed the tumor bulk and residual cells in the panel of CRC cell lines, rapidly inactivated c-Myc, STAT3, and NF-κB, and then decreased the protein levels of key signaling molecules for CRC, such as β-catenin, Notch1, and the nodes of mTOR pathways; eukaryotic translation initiation factors (eIF4F); anti-apoptotic proteins (Bcl-xl, Mcl-1, and survivin); and stemness-supporting molecules (CD133, Bim-1, and VEGF). In terms of mechanism of action, concurrent downregulation of Mcl-1, Bcl-xl, and survivin was necessary for CADPE to kill CRC bulk cells, while additional depletion of CD133 and VEGF proteins was required for killing the residual CRC cells. Moreover, the disabled c-Myc, STAT3, NF-κB, and eIF4F were associated with the broadly decreased levels of anti-apoptosis proteins and pro-stemness proteins. Consistently, CADPE suppressed CRC tumor growth associated with robust apoptosis and depleted levels of c-Myc, STAT3, NF-κB, eIF4F, anti-apoptotic proteins, and pro-stemness proteins. Our findings showed the promise of CADPE for treating CRC and suggested a rational polytherapy that disables c-Myc, STAT3, NF-κB, and eIF4F for killing CRC residual disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41419-020-03191-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7667164PMC
November 2020

Near-IR absorbing J-aggregates of a phenanthrene-fused BODIPY as a highly efficient photothermal nanoagent.

Chem Commun (Camb) 2020 Nov;56(93):14709-14712

The Key Laboratory of Functional Molecular Solids, Ministry of Education, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, China.

A phenanthrene-[b]-fused BODIPY exhibited well-defined J-aggregation behavior in both pure hydrocarbon solution and aqueous solution. The highly stable J-aggregates showed narrowed and largely red-shifted absorption with λmax of 840 nm and enhanced molar absorption coefficients (271 000 M-1 cm-1). Encapsulation of J-aggregates within a micellar nanocapsule resulted in nanoparticles that demonstrated good biocompatibility, excellent photothermal stability, high photothermal conversion ability (η ∼ 46.9%) and an effective phototoxicity (IC50 ∼ 2 μg mL-1 in HeLa cells) under 808 nm laser irradiation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0cc06014cDOI Listing
November 2020

Isolation and identification of microorganisms in Kazakhstan koumiss and their application in preparing cow-milk koumiss.

J Dairy Sci 2021 Jan 6;104(1):151-166. Epub 2020 Nov 6.

College of Food Science and Engineering, Northwest A & F University, Yangling, Shaanxi Province, China 712100. Electronic address:

Koumiss is a type of famous fermented mare milk and considered an important nutritious beverage in central Asian countries. However, the production of koumiss cannot meet public demand in the market due to availability of mare milk. In the present study, 52 lactic acid bacteria and 20 yeast strains from traditional homemade Kazakhstan koumiss were isolated and identified. The isolates were used in a trial that included fermented cow milk, and the flavor profiles, color, and taste to determine their contribution in the co-fermentation of cow milk. Based on the sensory evaluation, KZLAB13 and KZY10 strains were selected as the best cofermentation combinations. The optimal fermentation conditions were confirmed as the ratio of the starter culture 2.4:1.6 % (vol/vol) KZLAB13 strain to KZY10 strain and a temperature of 36°C for 16 h using response surface methodology. After evaluating the quality of the optimized cow-milk koumiss compared with the Kazakhstan koumiss, results suggested that cow milk fermented by these 2 strains possessed a promising taste, flavor, and physicochemical and rheological properties. Altogether, our results showed that cow milk fermented with a combination of KZLAB13 and KZY10 strains can simulate the taste, flavor, and quality of traditional koumiss. Our study provided a novel alternative to mare-milk koumiss and could be used in dairy programs to fulfill the needs of people.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3168/jds.2020-18527DOI Listing
January 2021

An improved multivariate model that distinguishes COVID-19 from seasonal flu and other respiratory diseases.

Aging (Albany NY) 2020 10 21;12(20):19938-19944. Epub 2020 Oct 21.

School of Medicine, University of California, San Diego, CA 92093, USA.

COVID-19 shared many symptoms with seasonal flu, and community-acquired pneumonia (CAP) Since the responses to COVID-19 are dramatically different, this multicenter study aimed to develop and validate a multivariate model to accurately discriminate COVID-19 from influenza and CAP. Three independent cohorts from two hospitals (50 in discovery and internal validation sets, and 55 in the external validation cohorts) were included, and 12 variables such as symptoms, blood tests, first reverse transcription-polymerase chain reaction (RT-PCR) results, and chest CT images were collected. An integrated multi-feature model (RT-PCR, CT features, and blood lymphocyte percentage) established with random forest algorism showed the diagnostic accuracy of 92.0% (95% CI: 73.9 - 99.1) in the training set, and 96. 6% (95% CI: 79.6 - 99.9) in the internal validation cohort. The model also performed well in the external validation cohort with an area under the receiver operating characteristic curve of 0.93 (95% CI: 0.79 - 1.00), an F1 score of 0.80, and a Matthews correlation coefficient (MCC) of 0.76. In conclusion, the developed multivariate model based on machine learning techniques could be an efficient tool for COVID-19 screening in nonendemic regions with a high rate of influenza and CAP in the post-COVID-19 era.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.18632/aging.104132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7655178PMC
October 2020

Selective usage of ANP32 proteins by influenza B virus polymerase: Implications in determination of host range.

PLoS Pathog 2020 10 12;16(10):e1008989. Epub 2020 Oct 12.

State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin, P. R. China.

The influenza B virus (IBV) causes seasonal influenza and has accounted for an increasing proportion of influenza outbreaks. IBV mainly causes human infections and has not been found to spread in poultry. The replication mechanism and the determinants of interspecies transmission of IBV are largely unknown. In this study, we found that the host ANP32 proteins are required for the function of the IBV polymerase. Human ANP32A/B strongly supports IBV replication, while ANP32E has a limited role. Unlike human ANP32A/B, chicken ANP32A has low support activity to IBV polymerase because of a unique 33-amino-acid insert, which, in contrast, exhibits species specific support to avian influenza A virus (IAV) replication. Chicken ANP32B and ANP32E have even lower activity compared with human ANP32B/E due to specific amino acid substitutions at sites 129-130. We further revealed that the sites 129-130 affect the binding ability of ANP32B/E to IBV polymerase, while the 33-amino-acid insert of chicken ANP32A reduces its binding stability and affinity. Taken together, the features of avian ANP32 proteins limited their abilities to support IBV polymerase, which could prevent efficient replication of IBV in chicken cells. Our results illustrate roles of ANP32 proteins in supporting IBV replication and may help to understand the ineffective replication of IBV in birds.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1371/journal.ppat.1008989DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7580981PMC
October 2020

Enhanced Cadaverine Production by Engineered Escherichia coli Using Soybean Residue Hydrolysate (SRH) as a Sole Nitrogen Source.

Appl Biochem Biotechnol 2021 Feb 10;193(2):533-543. Epub 2020 Oct 10.

State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical, Nanjing Tech University, Nanjing, 210009, China.

An economical source of nitrogen is one of the major limiting factors for sustainable cadaverine production. The utilization potential of soybean residue for enhanced cadaverine production by engineered Escherichia coli DFC1001 was investigated in this study. The SRH from soybean residue could get the protein extraction rate (PE) of 67.51% and the degree of protein hydrolysis (DH) of 22.49%. The protein molecular weights in SRH were mainly distributed in 565 Da (72.28%) and 1252 Da (17.11%). These proteins with small molecular weights and concentrated molecular weight distribution were favorable to be transformed by engineered E. coli DFC1001, and then SRH replaced completely yeast powder as an only nitrogen source for cadaverine production. The maximum cadaverine productivity was 0.52 g/L/h, achieved with a constant speed feeding strategy in the optimized SRH fermentation medium containing an initial total sugar concentration of 30 g/L and exogenous added minerals, which indicated that soybean residue could be a potential feedstock for economic cadaverine production.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12010-020-03444-1DOI Listing
February 2021

Strategic Construction of Ethene-Bridged BODIPY Arrays with Absorption Bands Reaching the Near-Infrared II Region.

Org Lett 2020 10 24;22(19):7513-7517. Epub 2020 Sep 24.

The Key Laboratory of Functional Molecular Solids, Ministry of Education, School of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China.

An efficient strategy for the controllable synthesis of BODIPY arrays based on the Stille cross-coupling reaction has been developed, from which a family of well-defined ethene-bridged BODIPY arrays from dimer to hexamer was synthesized. These arrays showed strong absorptions reaching the near-infrared II (NIR II, 1000-1700 nm) region with maxima tunable from 702 nm (dimer) to 1114 nm (hexamer) and possessed efficient light-harvesting capabilities, excellent photostability, and good photothermal conversion abilities under NIR light irradiation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.orglett.0c02704DOI Listing
October 2020

N-Substituted Phenothiazines as Environmentally Friendly Hole-Transporting Materials for Low-Cost and Highly Stable Halide Perovskite Solar Cells.

ACS Omega 2020 Sep 1;5(36):23334-23342. Epub 2020 Sep 1.

Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, FI-33014 Tampere, Finland.

Most of the high-performing halide perovskite solar cells (PSCs) leverage toxic chlorinated solvents (e.g., -dichlorobenzene or chlorobenzene) for the hole-transporting material (HTM) processing and/or antisolvents in the perovskite film fabrication. To minimize the environmental and health-related hazards, it is highly desirable, yet at the same time demanding, to develop HTMs and perovskite deposition processes relying on nonhalogenated solvents. In this work, we designed two small molecules, and , and synthesized them via simple and environmentally friendly Schiff base chemistry, by condensation of electron-donating triarylamine and phenothiazine moieties connected through an azomethine bridge. The molecules are implemented as HTMs in PSCs upon processing in a nonchlorinated (toluene) solvent, rendering their synthesis and film preparation eco-friendly. The enhancement in the power conversion efficiency (PCE) was achieved when switching from (9.77%) to (11.62%), in which the thioethyl group is introduced in the 2-position of the phenothiazine ring. Additionally, unencapsulated PSCs based on displayed excellent stabilities (75% of the initial PCEs is retained after 6 months of air exposure for to be compared with a 48% decrease of the initial PCE for Spiro-OMeTAD-based devices). The outstanding stability and the extremely low production cost ( = 9.23 $/g and = 9.03 $/g), together with the environmentally friendly synthesis, purification, and processing, make these materials attractive candidates as HTMs for cost-effective, stable, and eco-friendly PSCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsomega.0c03184DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7496006PMC
September 2020

A Novel NiFeO/Paper-Based Magnetoelastic Biosensor to Detect Human Serum Albumin.

Sensors (Basel) 2020 Sep 16;20(18). Epub 2020 Sep 16.

MicroNano System Research Center, Key Lab of Advanced Transducers and Intelligent Control System of the Ministry of Education and College of Information and Computer, Taiyuan University of Technology, Jinzhong 030600, China.

For the first time, a novel NiFeO/paper-based magnetoelastic (ME) biosensor was developed for rapid, sensitive, and portable detection of human serum albumin (HSA). Due to the uniquely magnetoelastic effect of NiFeO nanoparticles and the excellent mechanical properties of the paper, the paper-based ME biosensor transforms the surface stress signal induced by the specific binding of HSA and antibody modified on the paper into the electromagnetic signal. The accumulated binding complex generates a compressive stress on the biosensor surface, resulting in a decrease in the biosensor's static magnetic permeability, which correlates to the HSA concentrations. To improve the sensitivity of the biosensor, the concentration of NiFeO nanofluid and the impregnated numbers of the NiFeO nanofluid-impregnated papers were optimized. The experimental results demonstrated that the biosensor exhibited a linear response to HSA concentrations ranging from 10 μg∙mL to 200 μg∙mL, with a detection limit of 0.43 μg∙mL, which is significantly lower than the minimal diagnosis limit of microalbuminuria. The NiFeO/paper-based ME biosensor is easy to fabricate, and allows the rapid, highly-sensitive, and selective detection of HSA, providing a valuable analytical device for early monitoring and clinical diagnosis of microalbuminuria and nephropathy. This study shows the successful integration of the paper-based biosensor and the ME sensing analytical method will be a highly-sensitive, easy-to-use, disposable, and portable alternative for point-of-care monitoring.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/s20185286DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7570998PMC
September 2020

A Biomimetic Polymer Magnetic Nanocarrier Polarizing Tumor-Associated Macrophages for Potentiating Immunotherapy.

Small 2020 09 18;16(38):e2003543. Epub 2020 Aug 18.

Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China.

The progress of antitumor immunotherapy is usually limited by tumor-associated macrophages (TAMs) that account for the highest proportion of immunosuppressive cells in the tumor microenvironment, and the TAMs can also be reversed by modulating the M2-like phenotype. Herein, a biomimetic polymer magnetic nanocarrier is developed with selectively targeting and polarizing TAMs for potentiating immunotherapy of breast cancer. This nanocarrier PLGA-ION-R837 @ M (PIR @ M) is achieved, first, by the fabrication of magnetic polymer nanoparticles (NPs) encapsulating Fe O NPs and Toll-like receptor 7 (TLR7) agonist imiquimod (R837) and, second, by the coating of the lipopolysaccharide (LPS)- treated macrophage membranes on the surface of the NPs for targeting TAMs. The intracellular uptake of the PIR @ M can greatly polarize TAMs from M2 to antitumor M1 phenotype with the synergy of Fe O NPs and R837. The relevant mechanism of the polarization is deeply studied through analyzing the mRNA expression of the signaling pathways. Different from previous reports, the polarization is ascribed to the fact that Fe O NPs mainly activate the IRF5 signaling pathway via iron ions instead of the reactive oxygen species-induced NF-κB signaling pathway. The anticancer effect can be effectively enhanced through potentiating immunotherapy by the polarization of the TAMs in the combination of Fe O NPs and R837.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.202003543DOI Listing
September 2020

Single-molecule enzymatic reaction dynamics and mechanisms of GPX3 and TRXh9 from Arabidopsis thaliana.

Spectrochim Acta A Mol Biomol Spectrosc 2020 Dec 4;243:118778. Epub 2020 Aug 4.

State Key Laboratory of Crop Stress Adaptation and Improvement, Henan University, Kaifeng 475004, China; School of Physics and Electronics, International Joint Research Laboratory of New Energy Materials and Devices of Henan Province, Henan University, Kaifeng 475004, China. Electronic address:

Glutathione peroxidases (GPXs) regulate the levels of reactive oxygen species in cells and tissues. During the redox cycling, the plant GPX is regenerated by thioredoxins (TRXs) as reductant rather than glutathione as the electron donor. However, the direct experimental observation on the interaction dynamics between GPXs and TRXs has not been reported, and the redox mechanism is unclear. In this work, the protein interactions between oxidized AtGPX3 and reduced AtTRXh9 have been studied using single-molecule fluorescence resonance energy transfer (smFRET). The obtained results indicate there are four processes in these two protein interaction, including biological recognition, binding, intermediate and unbinding state. Two enzymatic reaction intermediate states have been identified in the dissociation of AtGPX3-AtTRXh9 complex from binding to unbinding state, suggesting two types of interaction pathways and intermediate complexes. In particular, the dynamical study reveals that the redox reaction between oxidized AtGPX3 and reduced AtTRXh9 is realized through the forming and breaking of disulfide bonds via the active sites of Cys4 and Cys57 in AtTRXh9. These findings are of significant for deep understanding the redox reaction and mechanism between GPXs and TRXs enzymes, and studying other protein dynamics at single-molecule level.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.saa.2020.118778DOI Listing
December 2020

Methylation in combination with temperature programming enables rapid identification of polysaccharides by ambient micro-fabrication glow discharge plasma (MFGDP) desorption ionization mass spectrometry.

Talanta 2020 Oct 15;218:121156. Epub 2020 May 15.

Research Center of Analytical Instrumentation, Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, Shaanxi, 710069, China. Electronic address:

Obtaining the fingerprints of polysaccharides was known to be notoriously difficult by ambient mass spectrometry due to their resistance for desorption and ionization. Ambient mass spectrometry technology has recently been recognized as a quick analysis tool for obtaining fingerprints, which is attributed to its characteristics of no sample pretreatment and easy operation under atmospheric pressure. However, it still remains a challenge for accurate identification of the fingerprints of macromolecular polysaccharides by ambient micro-fabrication glow discharge plasma (MFGDP). In this study, a simplified methylation method was introduced to realize rapid analysis of polysaccharide mixture by MFGDP with the assistance of a temperature-programmed system (TPS). At the optimal temperature of TPS, oligosaccharides, plant polysaccharides and polysaccharide mixtures were all well characterized by TPS-MFGDP. In the proposed method, the characteristic [M + NH] adduct ions of oligosaccharides ions of oligosaccharides that are difficult for other ambient mass spectrometric methods were abundantly produced, making it possible to simultaneously identify a mixture of five or more polysaccharides. In addition, a supervised classification model which based on MS spectra, was used to classify seven typical hypoglycemic polysaccharides with excellent sensitivity, specificity and accuracy, indicating the good classification performance of the RF model constructed. Thus, the proposed mass spectroscopic method provides a cost effective, accurate and high throughput tool for identification and classification of polysaccharides, which is beneficial for studying the biological activity of polysaccharides.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.talanta.2020.121156DOI Listing
October 2020

Mining, heterologous expression, purification and characterization of 14 novel bacteriocins from Lactobacillus rhamnosus LS-8.

Int J Biol Macromol 2020 Dec 10;164:2162-2176. Epub 2020 Aug 10.

College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi Province 712100, China. Electronic address:

Bacteriocins are a subclass of antibacterial peptides considered to be the most promising alternative to antibiotics. A large number of unknown bacteriocins are hidden in lactic acid bacteria. In this study, by combining the genome with LC-MS/MS, 14 novel bacteriocins produced by Lactobacillus rhamnosus LS-8 were detected. Moreover, these bacteriocins were successfully cloned via plasmid pET-28a(+) and pET-30a(+) and heterologously expressed in Escherichia coli BL21. Escherichia coli ATCC25922 and Staphylococcus aureus ATCC25923 were used to confirm their antibacterial activity. Subsequently, the four bacteriocins (pH 25, S68, S81, and S137) with the strongest antibacterial ability were selected, and their expression conditions were optimized. Purification was performed by cation exchange chromatography and high performance liquid chromatography, and the active parts were collected and analyzed by mass spectrometry. The mass spectrometry analysis revealed that peptide coverage was >71.39%. The MICs of the four bacteriocins against four pathogenic bacteria ranged from 5.38 to 19.84 μg/mL. In addition, these bacteriocins significantly inhibited the growth of four standard pathogenic bacteria. They also exhibited broad-spectrum bacteriostasis on Gram-positive and Gram-negative bacteria. Therefore, these new bacteriocins have great potential in the study of alternative antibiotics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ijbiomac.2020.08.067DOI Listing
December 2020