Publications by authors named "Lanhua Yi"

14 Publications

  • Page 1 of 1

Investigation of antibiofilm activity, antibacterial activity, and mechanistic studies of an amphiphilic peptide against Acinetobacter baumannii.

Biochim Biophys Acta Biomembr 2021 Jun 3;1863(6):183600. Epub 2021 Mar 3.

State Key Laboratory of Chemical Biology and Drug Discovery and Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. Electronic address:

Biofilm-producing pathogens, such as Acinetobacter baumannii, have aroused escalating attention. Because these bacteria could secrete mixture with close-knit architecture and complicated components to resist traditional antibiotics. Here, we reported an amphiphilic peptide denoted as zp3 (GIIAGIIIKIKK-NH), which showed favorable bioactivity against Acinetobacter baumannii ATCC 19606 (minimal inhibitory concentration, MIC = 4 μM) and low cytotoxicity to mammalian cells Vero (half maximal inhibitory concentration, IC > 100 μM). Importantly, zp3 could inhibit the formation of biofilm at micromole level and eliminate around 50% preformed biofilm at 32 μM after 6 h treatment. This peptide was able to bind with biofilm while maintaining a helical structure in a mimic biofilm-rich environment. In vivo test demonstrated that zp3 rescued 33.3% of larvae after 48 h infection and reduced 1 log live bacteria inside the animal body after 6 h treatment. The bactericidal mode for zp3 was attributed to the combination of influencing ions balance at low concentration and inducing permeability alteration and pore formation on the Acinetobacter baumannii membrane at high concentration. Application on medical textiles also proved that zp3 could perform a good antibacterial activity in practice.
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http://dx.doi.org/10.1016/j.bbamem.2021.183600DOI Listing
June 2021

Induces Resistance in Postharvest Citrus by Activating the Phenylpropanoid Biosynthesis Pathway.

J Agric Food Chem 2021 Mar 17;69(8):2619-2631. Epub 2021 Feb 17.

College of Food Science, Southwest University, Chongqing 400715, PR China.

This study aimed to investigate the effect of on disease resistance and elucidate the changes in phenylpropane biosynthesis treated by in postharvest citrus. The results showed that reduced the disease incidence and lesion diameters without direct contact with the pathogen . Transcriptome analysis revealed that phenylpropanoid biosynthesis was triggered by . Genes encoding phenylpropanoid biosynthesis were upregulated, including phenylalanine ammonia-lyase (PAL), 4-coumaroyl-CoA ligase (4CL), cinnamate-4-hydroxylase (C4H), peroxidase (POD), cinnamyl alcohol dehydrogenase (CAD), O-methyltransferase, and hydroxyl cinnamoyl transferase. Moreover, increased the activity of PAL, 4CL, C4H, POD, polyphenol oxidase, and CAD in citrus pericarp. In addition, treated citrus displayed higher levels of total phenolic compounds, flavonoid, and lignin and higher amounts of ferulic and sinapic acid. In conclusion, these results suggested that could induce resistance through modulating the pathway of phenylpropanoid biosynthesis in postharvest citrus.
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http://dx.doi.org/10.1021/acs.jafc.0c06283DOI Listing
March 2021

Exfoliated graphdiyne for the electroless deposition of Au nanoparticles with high catalytic activity.

Analyst 2021 Jan 12;146(2):444-449. Epub 2020 Nov 12.

Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, School of Chemistry, Xiangtan University, Xiangtan 411105, P. R. China.

Graphdiyne (GDY), a novel two-dimensional (2D) carbon material with sp- and sp-hybridized carbon atoms, has earned a lot of attention in recent years. Owing to its low reduction potential and highly conjugated electronic structure, it can be used as a reducing agent and stabilizer for the electroless deposition of highly dispersed Au nanoparticles. In this paper, we observe that exfoliated GDY (eGDY), the exfoliation of bulk GDY into single- or few-layered GDY in aqueous solution, can be used as an excellent substrate for the electroless deposition of very small Au nanoparticles to form a Au/eGDY nanocomposite that exhibits higher catalytic performance for the reduction of 4-nitrophenol. The higher catalytic performance is considered to arise from the high specific surface area of eGDY and the electroless deposition of active metal catalysts with eGDY as the support. Our results inspired the present investigation into the use of eGDY for the development of highly efficient catalysts.
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http://dx.doi.org/10.1039/d0an01814gDOI Listing
January 2021

Effects of Peptide C-OOWW-NH on Transcriptome and Cell Wall of the Postharvest Fungal Pathogen .

Front Microbiol 2020 17;11:574882. Epub 2020 Sep 17.

College of Food Science, Southwest University, Chongqing, China.

In this study, the transcriptional profiling of after COTR treatment was analyzed by RNA-Seq technology. A total of 2562 and 667 genes in were differentially expressed after 2 and 12 h treatment, respectively. These genes were respectively mapped to 91 and 79 KEGG pathways. The expression patterns of differentially expressed genes (DEGs) at 2 and 12 h were similar, mainly were the metabolic processes in cell wall, cell membrane, genetic information and energy. Particularly, the main metabolic process which was affected by COTR stress for 2 and 12 h was cell integrity, including cell wall and cell membrane. The changes of chitin in cell wall was observed by Calcofluor White (CFW) staining assay. The weaker blue fluorescence in the cell wall septa, the decrease of β-1, 3-glucan synthase activity and the increase of chitinase and AKP activity showed that COTR could damage the cell wall integrity. In conclusion, these results suggested that COTR could inhibit the growth of through various mechanisms at transcriptional level, and could influence the cell wall permeability and integrity.
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http://dx.doi.org/10.3389/fmicb.2020.574882DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527529PMC
September 2020

Characterization and antibacterial action mode of bacteriocin BMP32r and its application as antimicrobial agent for the therapy of multidrug-resistant bacterial infection.

Int J Biol Macromol 2020 Dec 20;164:845-854. Epub 2020 Jul 20.

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

Multidrug-resistant (MDR) bacterial infection still poses a serious threat to public health, therefore, effective and safe antimicrobial agents are urgently needed. In this study, recombinant bacteriocin BMP32 (BMP32r) prepared by the Escherichia coli expression system had a broad-spectrum antibacterial activity even against some MDR bacteria and its minimum inhibitory concentration ranged from 9.2 to 36.8 mg/L. Furthermore, BMP32r showed good stable performance in heat, pH and storage. Moreover, the scanning electron microscope and transmission electron microscope revealed that BMP32r killed indicator strains through cell wall destruction, pore formation, and the membrane permeability increasing which was proved by propidium iodide uptake investigation. The wound healing of an animal MDR S. aureus infected model was promoted by BMP32r, and the safety was verified by the cytotoxicity assay that the viability of HFF cells remained 87.3% in even when the concentration of BMP32r was as high as 147.2 mg/L. In addition, no abnormalities or damages to major organs was found in vivo assessments after treatment with BMP32r. In conclusion, BMP32r has great potential to be developed as a safe antimicrobial agent to treat MDR bacterial infections.
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http://dx.doi.org/10.1016/j.ijbiomac.2020.07.192DOI Listing
December 2020

Screening antagonistic yeasts against citrus green mold and the possible biocontrol mechanisms of Pichia galeiformis (BAF03).

J Sci Food Agric 2020 Aug 28;100(10):3812-3821. Epub 2020 May 28.

College of Food Science, Southwest University, Chongqing, China.

Background: Penicillium digitatum is one of the most important pathogens causing citrus green mold, leading to significant economic losses. Traditionally, synthetic fungicides are used to control diseases. However, the side effects of fungicides should not be ignored. Thus, antagonistic yeasts were proposed to be safe and effective alternatives for managing diseases. Orchards are excellent sources of naturally occurring antagonists against pathogens. Therefore, in the present study, antagonistic yeasts obtained from orchards were screened, and the possible biocontrol mechanisms of the most promising yeast were investigated.

Results: Seventy-eight isolates of yeasts (15 species of 10 genera) were obtained from citrus orchards. In in vitro assays, 16 strains showed antifungal activity against Pichia digitatum and 15 strains showed biocontrol potential against green mold on Olinda oranges. Pichia galeiformis (BAF03) exhibited the best antagonistic activity against P. digitatum during 6 days storage at 25 °C and a good antagonistic activity during 29 days at 4 °C. Pichia galeiformis (BAF03) could colonize and amplify quickly in wounded citrus. Scanning electron microscopy results showed that the citrus wound was colonised by the yeast. A total of eight volatile organic compounds (VOCs) were identified by gas chromatography-mass spectrometry The VOCs produced by P. galeiformis (BAF03) efficiently inhibited P. digitatum.

Conclusion: Pichia galeiformis (BAF03) isolated from a citrus orchard showed potential to control postharvest green mold of citrus. The possible mechanisms of action likely include competition for space and nutrients as well as production of VOCs.
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http://dx.doi.org/10.1002/jsfa.10407DOI Listing
August 2020

Biocontrol ability and action mechanism of Metschnikowia citriensis against Geotrichum citri-aurantii causing sour rot of postharvest citrus fruit.

Food Microbiol 2020 May 8;87:103375. Epub 2019 Nov 8.

College of Food Science, Southwest University, Chongqing, 400715, PR China; Food Storage and Logistics Research Center, Southwest University, Chongqing, 400715, PR China. Electronic address:

This study investigated the biocontrol efficiency of Metschnikowia citriensis strain FL01 against Geotrichum citri-aurantii, and evaluated possible mechanisms. The results showed that M. citriensis could effectively control the development of sour rot, and significantly inhibit the mycelial growth and spore germination of G. citri-aurantii. The population dynamics results and Scanning electron microscopy (SEM) analysis indicated that M. citriensis could rapidly colonize wounds and tightly adhere to the surface of the wounds to compete with G. citri-aurantii for nutrition and space. M. citriensis also showed the biofilm formation action in vitro. The response of G. citri-aurantii to different components of M. citriensis culture showed that only the yeast cells but not the extracellular metabolites and the volatile organic compounds (VOCs) exhibited inhibitory effect on the growth of G. citri-aurantii. M. citriensis adhered to the hyphae of G. citri-aurantii loosely and sparsely, and the production of lytic enzymes β-1, 3-glucanase (GLU) and Chitinase (CHI) could not be induced by G. citri-auranti. Iron affected the pulcherrimin pigment production and antagonism of M. citriensis indicating iron depletion as the most important antagonistic mechanism. Besides, M. citriensis also induced resistance of fruit against sour rot. These results suggested that M. citriensis could be used as the potential alternative of fungicides to control postharvest pathogens on citrus fruit.
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http://dx.doi.org/10.1016/j.fm.2019.103375DOI Listing
May 2020

Proline Increases Pigment Production to Improve Oxidative Stress Tolerance and Biocontrol Ability of .

Front Microbiol 2019 11;10:1273. Epub 2019 Jun 11.

College of Food Science, Southwest University, Chongqing, China.

Utilizing antagonistic yeasts is a promising approach for managing postharvest decay of fruits. However, it is well established that various severe stresses encountered in the environment and production process cause the intracellular reactive oxygen species (ROS) accumulation in yeast cells, resulting in cell damage and loss of vitality. Here, proline has been shown to function as a cell protectant and inducer of biofilm formation able to increase the oxidative stress tolerance and the biocontrol ability of the antagonistic yeast . Addition of proline to cells induced a significant rise in superoxide dismutase (SOD) and catalase (CAT) activity in the early and late stages of oxidative stress, respectively, and increased the maroon pigment production that directly reduced intracellular iron content and indirectly diminished intracellular ROS levels and thus inhibited ROS- and iron-induced apoptosis. Treating cells with iron chelator tropolone yielded similar results. Pigment production induced by proline also enhanced the capability of biofilm formation of . These results suggested an important role for pigment of in response to oxidative stress. The abilities of proline to scavenge intracellular ROS and inhibit apoptosis, increase pigment production, and promote biofilm formation contribute to the improvements in oxidative stress tolerance and biocontrol efficacy of .
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http://dx.doi.org/10.3389/fmicb.2019.01273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6580863PMC
June 2019

A rhodamine-deoxylactam based fluorescent probe for fast and selective detection of nitric oxide in living cells.

Talanta 2019 May 17;197:436-443. Epub 2019 Jan 17.

Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, PR China. Electronic address:

Nitric oxide (NO) plays vital roles in many physiological process and is closely related to many diseases. So far, a number of fluorescent probes have been constructed for the detection of NO successfully. However, the probes still suffer from long-time reaction and limited selectivity. Herein, a fluorescent probe named dRB-OPD is synthesized and used to recognize NO. The probe contains a deoxy-rhodamine B as fluorophore and o-phenylenediamino as reaction site. dRB-OPD shows fast response to NO within 40 s with 170-fold fluorescence enhancement. Moreover, the probe shows high selectivity towards NO over dehydroascorbic acid (DHA), ascorbic acid (AA), and methylglyoxal (MGO). Particularly, the probe can avoid the serious interference from cysteine (Cys) found in the rhodamine lactam-based fluorescent NO probes (RB-OPD). In addition, the probe is applied for the detection of exogenous and endogenous NO in the HepG2 and RAW 264.7 cells with satisfactory results.
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http://dx.doi.org/10.1016/j.talanta.2019.01.061DOI Listing
May 2019

Efficient Exploitation of Multiple Novel Bacteriocins by Combination of Complete Genome and Peptidome.

Front Microbiol 2018 13;9:1567. Epub 2018 Jul 13.

Department of Food Nutrition and Safety, College of Food Science and Engineering, Northwest A&F University, Yangling, China.

The growing emergence of antibiotic-resistant pathogens including the most dangerous superbugs requires quick discovery of novel antibiotics/biopreservatives for human health and food safety. Bacteriocins, a subgroup of antimicrobial peptides, have been considered as promising alternatives to antibiotics. Abundant novel bacteriocins are stored in genome sequences of lactic acid bacteria. However, discovery of novel bacteriocins still mainly relies on dubious traditional purification with low efficiency. Moreover, sequence alignment is invalid for novel bacteriocins which have no homology to known bacteriocins in databases. Therefore, an efficient, simple, universal, and time-saving method was needed to discover novel bacteriocins. Crude bacteriocins from both cell-related and culture supernatant of MN047 fermentation were applied to LC-MS/MS for peptidome assay, by which 131 extracellular peptides or proteins were identified in the complete genome sequence of MN047. Further, the genes of suspected bacteriocins were verified by expressed in BL21 (DE3) pLysS. Thereafter, eight novel bacteriocins and two nonribosomal antimicrobial peptides were identified to be broad-spectrum activity against both Gram-positive and Gram-negative bacteria, including some multidrug-resistant strains. Among them, BM1556 located within predicted bacteriocin gene cluster. The most active bacteriocin BM1122 had low MIC values of 13.7 mg/L against both ATCC29213 and ATCC25922. The BM1122 had bactericidal action mode by biofilm-destruction, pore-formation, and membrane permeability change. The combination of complete genome and peptidome is a valid approach for quick discovery of novel bacteriocins without/with-low homology to known ones. This method will contribute to deep exploitation of novel bacteriocins in genome of bacteria submitted to GenBank.
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http://dx.doi.org/10.3389/fmicb.2018.01567DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6053492PMC
July 2018

New Strategy on Antimicrobial-resistance: Inhibitors of DNA Replication Enzymes.

Authors:
Lanhua Yi Xin Lü

Curr Med Chem 2019 ;26(10):1761-1787

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

Background: Antimicrobial resistance is found in all microorganisms and has become one of the biggest threats to global health. New antimicrobials with different action mechanisms are effective weapons to fight against antibiotic-resistance.

Objective: This review aims to find potential drugs which can be further developed into clinic practice and provide clues for developing more effective antimicrobials.

Methods: DNA replication universally exists in all living organisms and is a complicated process in which multiple enzymes are involved in. Enzymes in bacterial DNA replication of initiation and elongation phases bring abundant targets for antimicrobial development as they are conserved and indispensable. In this review, enzyme inhibitors of DNA helicase, DNA primase, topoisomerases, DNA polymerase and DNA ligase were discussed. Special attentions were paid to structures, activities and action modes of these enzyme inhibitors.

Results: Among these enzymes, type II topoisomerase is the most validated target with abundant inhibitors. For type II topoisomerase inhibitors (excluding quinolones), NBTIs and benzimidazole urea derivatives are the most promising inhibitors because of their good antimicrobial activity and physicochemical properties. Simultaneously, DNA gyrase targeted drugs are particularly attractive in the treatment of tuberculosis as DNA gyrase is the sole type II topoisomerase in Mycobacterium tuberculosis. Relatively, exploitation of antimicrobial inhibitors of the other DNA replication enzymes are primeval, in which inhibitors of topo III are even blank so far.

Conclusion: This review demonstrates that inhibitors of DNA replication enzymes are abundant, diverse and promising, many of which can be developed into antimicrobials to deal with antibioticresistance.
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http://dx.doi.org/10.2174/0929867324666171106160326DOI Listing
July 2019

First Report on the Complete Genome Sequence of MN047, a Potent Probiotic Strain Isolated from Koumiss in China.

Genome Announc 2017 Mar 23;5(12). Epub 2017 Mar 23.

College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi Province, China

The complete genome sequence of deciphered by PacBio RS II and Illumina HiSeq 4000 sequencing was first reported with one chromosome and two plasmids. Sequence analysis of MN047 showed probiotic characteristics.
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http://dx.doi.org/10.1128/genomeA.00048-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5364219PMC
March 2017

Purification and characterization of a novel bacteriocin produced by Lactobacillus crustorum MN047 isolated from koumiss from Xinjiang, China.

J Dairy Sci 2016 Sep 8;99(9):7002-7015. Epub 2016 Aug 8.

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

The growing emergence of antibiotic-resistant bacteria in the food industry needs to be controlled with effective antimicrobials. In this study, bacteriocin MN047 A (BMA) was found to have antibacterial activity against multidrug-resistant bacteria. It was produced by Lactobacillus crustorum MN047, which was first isolated from koumiss, a traditional fermented dairy product from Xinjiang Autonomous Region, China. It was purified by ammonium sulfate precipitation, ion-exchange chromatography, and reversed-phase chromatography. It had a low molecular mass of 1,770.89 Da according to matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and the sequence was identified as QLPWQILGIVAGMFQA by liquid chromatography-tandem mass spectrometry analysis and MASCOT searching. It was proteinaceous in nature: the bacteriocin was digested by protease but not by α-amylase or lipase. It showed broad pH toleration (pH 2-11), good thermostability, and good storage stability. It had a broad inhibitory spectrum, including both gram-positive and gram-negative bacteria. Growth curve and time-kill kinetics indicated that it was bactericidal to the indicator strains, and this finding was verified by scanning electron microscope and transmission electron microscope after treatment with BMA. As well, BMA halted the growth of Staphylococcus aureus and Escherichia coli in the G1 and G2/M phases according to cell-cycle analysis by flow cytometry, indicating that BMA had comprehensive inhibitory effects against foodborne pathogens.
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http://dx.doi.org/10.3168/jds.2016-11166DOI Listing
September 2016

Electrochemical analysis of trifluralin using a nanostructuring electrode with multi-walled carbon nanotubes.

Environ Pollut 2008 Dec 9;156(3):1015-20. Epub 2008 Jun 9.

Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, PR China.

The electroanalytical behaviors of the endocrine-disrupting chemical trifluralin have been studied at a nanostructuring electrode. The nanostructuring electrode was fabricated by coating a uniform multi-wall carbon nanotubes/dihexadecyl hydrogen phosphate (MWNTs/DHP) film on glassy carbon electrode (GCE). The reduction peak currents of trifluralin increased remarkably and the reduction peak potential shifted positively at the nanostructuring electrode, compared with that at a bare GCE. The results showed that this nanostructuring electrode exhibited excellent enhancement effects on the electrochemical reduction of trifluralin. Consequently, a simple and sensitive electroanalytical method was developed for the determination of trifluralin. Under optimal conditions, a linear response of trifluralin was obtained in the range from 5.0 x 10(-9) to 6.0 x 10(-6) mol L(-1) (r=0.998) and with a limit of detect (LOD) of 2.0 x 10(-9) mol L(-1). The proposed procedure was successfully applied to determine trifluralin in soil samples with satisfactory results.
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http://dx.doi.org/10.1016/j.envpol.2008.05.002DOI Listing
December 2008