Publications by authors named "Meng Gui"

16 Publications

  • Page 1 of 1

Bioactive peptides identified from enzymatic hydrolysates of sturgeon skin.

J Sci Food Agric 2021 Sep 15. Epub 2021 Sep 15.

Beijing Fisheries Research Institute, Beijing Academy of Agricultural and Forestry Sciences, Beijing, China.

Background: Recent studies demonstrate that fish byproduct can be used as sources of bioactive peptides for functional foods. Sturgeon skin contains abundant proteins while it has commonly been discarded during sturgeon processing. The objective of the present work is to identify and characterize the bioactive peptides from protein hydrolysates of sturgeon skin.

Results: Sturgeon skin protein extract (SKPE) hydrolyzed by flavourzyme for 60 min exhibited high antioxidant activity, dipeptidyl peptidase IV (DPP-IV) and angiotensin converting enzyme (ACE) inhibitory activity. The sequences of peptides from flavourzyme hydrolysates were identified using HPLC-MS/MS. Gly-Asp-Arg-Gly-Glu-Ser-Gly-Pro-Ala (P1) showed the highest DPPH radical scavenging activity (DPPH IC50 = 1.93 mM). Gly-Pro-Ala-Gly-Glu-Arg-Gly-Glu-Gly-Gly-Pro-Arg (P11) (DPP-IV IC  = 2.14 mM) and Ser-Pro-Gly-Pro-Asp-Gly-Lys-Thr-Gly-Pro-Arg (P12) (DPP-IV IC  = 2.61 mM) exhibited the strongest DPP-IV inhibitory activity. Gly-Pro-Pro-Gly-Ala-Asp-Gly-Gln-Ala-Gly-Ala-Lys (P6) displayed the highest ACE inhibitory activity (ACE IC50 = 3.77 mM). The molecular docking analysis revealed that DPP-IV inhibition of P11 and P12 are mainly attributed to hydrogen bonds and hydrophobic interactions, whereas ACE inhibition of P6 is mainly attributed to strong hydrogen bonds.

Conclusions: These results indicated that SKPE hydrolysates generated by flavourzyme were potential sources of bioactive peptides that be uses in health food industry.
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http://dx.doi.org/10.1002/jsfa.11532DOI Listing
September 2021

Comparative Analysis of Chemical Constituents in Different Parts of Lotus by UPLC and QToF-MS.

Molecules 2021 Mar 25;26(7). Epub 2021 Mar 25.

School of Pharmaceutical Sciences, Jilin University, Fujin Road 1266, Changchun 130021, China.

Six parts of lotus (seeds, leaves, plumule, stamens, receptacles and rhizome nodes) are herbal medicines that are listed in the Chinese Pharmacopoeia. Their indications and functions have been confirmed by a long history of clinical practice. To fully understand the material basis of clinical applications, UPLC-QToF-MS combined with the UNIFI platform and multivariate statistical analysis was used in this study. As a result, a total of 171 compounds were detected and characterized from the six parts, and 23 robust biomarkers were discovered. The method can be used as a standard protocol for the direct identification and prediction of the six parts of lotus. Meanwhile, these discoveries are valuable for improving the quality control method of herbal medicines. Most importantly, this was the first time that alkaloids were detected in the stamen, and terpenoids were detected in the cored seed. The stamen is a noteworthy part because it contains the greatest diversity of flavonoids and terpenoids, but research on the stamen is rather limited.
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http://dx.doi.org/10.3390/molecules26071855DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8036816PMC
March 2021

[Prognostic Factors of Central Venous Catheter-related Bloodstream Infections].

Zhongguo Yi Xue Ke Xue Yuan Xue Bao 2020 Dec;42(6):789-794

Department of Laboratory,the Third Affiliated Hospital of Guizhou Medical University,Duyun,Guizhou 558000,China.

Objective To explore the prognostic factors of central venous catheter-related bloodstream infection(CR-BSI)and provide reference for clinical practice. Methods The clinical data of 346 CR-BSI patients from February 2014 to July 2019 were retrospectively reviewed,and the prognostic factors were analyzed. Results Of the 346 CR-BSI patients,62 died,yielding a case-fatality rate of 17.92%.Univariate analysis showed that 18 factors including age(=2.838,=0.006),history of diabetes(=5.966,=0.015),time to withdrawing the tube after infection(=5.026,=0.000),ICU stay(=6.885),=0.009),catheter placement(=5.468,=0.019),use of glucocorticoids(=4.731,=0.030),Acute Physiology and Chronic Health Score Ⅱ(APACHE Ⅱ)after CR-BSI(=3.556,=0.000),methicillin-resistant (MRSA)infection(=10.209,=0.001),multidrug-resistant (MDR-PA)infection(=22.668,=0.000),carbapenem-resistant (CRKP)infection(=16.758,=0.000),infection with extended-spectrum β-lactamase-producing enterobacteriaceae(=7.784,=0.005),fungal infection(=6.576,=0.010),use of antibacterial drugs before infection(=5.315,=0.021),combined use of antibacterial drugs before infection(=4.260,=0.039),time to start using antibacterial drugs(=2.805,=0.006),time to start using antibacterial drugs according to the results of susceptibility test(=2.877,=0.005),serum albumin concentration(=-2.976,=0.003),blood sugar(=2.632,=0.010)were associated with CR-BSI death.Multivariate logistic analysis showed that 6 factors including hyperglycemia(=5.047,95% =1.805-14.114,=0.002),MRSA infection(=18.278,95% =3.732-89.527,=0.000),MDR-PA infection(=42.380,95% =9.477-189.528, =0.000),CRKP infection(=72.834,95% =16.061-330.286,=0.000),increased APACHE Ⅱ score after CR-BSI(=6.615,95% =2.625-16.667, =0.000),time from infection to extubation(=4.071,95% =1.743-9.508, =0.001),and time from infection to use of antibiotics according to drug sensitivity test(=5.047,95% =1.805-14.114,=0.001)were independent risk factors for CR-BSI death.Serum albumin concentration(=0.365,95% =0.136-0.978,=0.045)was an independent protective factor for CR-BSI death. Conclusions Hyperglycemia,hypoproteinemia,critical illness,and multidrug-resistant bacterial infection are the risk factors for CR-BSI death.Early extubation,early bacterial culture,and early drug sensitivity test may help to reduce the mortality of CR-BSI.
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http://dx.doi.org/10.3881/j.issn.1000-503X.12266DOI Listing
December 2020

Sturgeon ()-Derived Chondroitin Sulfate Suppresses Human Colon Cancer HCT-116 Both In Vitro and In Vivo by Inhibiting Proliferation and Inducing Apoptosis.

Nutrients 2020 Apr 17;12(4). Epub 2020 Apr 17.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 10083, China.

Chondroitin sulfate (CS), mainly present in the cartilage and bone of animals, is known as a potential food-derived bioactive that has several biological functions, such as anti-arthritic and anti-inflammatory activity. Sturgeon (), an important fishery resource in China, contains an abundance of CS in their cartilage. In our previous study, we have extracted and purified CS from sturgeon cartilage. Herein, we further investigate the health benefits of sturgeon-derived chondroitin sulfate (SCS), especially for colorectal cancer treatment. The in vitro study indicated that SCS could inhibit the proliferation of the human colon cancer cell line HCT-116 in a dose-dependent manner, which was associated with cell cycle arrest. In addition, SCS also led to extensive cellular apoptosis in colon cancer cell HCT-116 cells. Meanwhile, an in vivo study showed that SCS treatment significantly inhibited the tumor development of xenograft HCT-116 in mice via proliferation suppression and apoptosis induction. Further, a mechanistic study demonstrated that the apoptosis induction was mainly due to the activation of the family-associated mitochondrial pathway. Overall, our results provided a basis for SCS as a promising agent against colon cancer.
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http://dx.doi.org/10.3390/nu12041130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7230714PMC
April 2020

[Risk Factors for Postoperative Recurrence of Chronic Suppurative Otitis Media].

Zhongguo Yi Xue Ke Xue Yuan Xue Bao 2020 Feb;42(1):62-66

Department of Clinical Laboratory,Third Affiliated Hospital of Guizhou Medical University,Duyun,Guizhou 558000,China.

To analyze the risk factors for postoperative recurrence of chronic suppurative otitis media(CSOM) and explore the intervention measures to prevent postoperative recurrence of CSOM. A total of 1066 patients with CSOM who underwent concurrent surgical treatment and achieved clinical cure in our hospital from January 2012 to December 2018 were enrolled.The clinical data and laboratory findings were reviewed by using an electronic medical record system and the patients were followed up for 1 year.The patients were divided into the non-recurrent group and the recurrent group.Chi-square test and multivariate logistic regression were used to compare the factors may contribute to the postoperative recurrence. The recurrence rate of CSOM was 6.38%.Multi-drug-resistant(MDR) infection before surgery(=16.338,=0.000),aged ≥60 years(=5.182,=0.023),frequency of occurrence ≥3 times/year(=4.388,=0.036),duration of active period>7 d(=4.729,=0.030),repeated upper respiratory tract infection>3 times/year(=11.913,=0.001),accompanied by chronic sinusitis(=11.077,=0.001),blood glucose>6.11 mmol/L(=15.327,=0.000),postoperative serum procalcitonin(PCT)>0.5 μg/L(=8.337,=0.004) were the risk factors for postoperative recurrence.The use of snorkel was a protective factor for postoperative recurrence(=5.308,=0.021).Multivariate analysis showed that MDR infection(=3.373,95%:1.825-6.234,=0.000),repeated upper respiratory tract infection>3 times/year(=2.727,95%:1.479-5.030,=0.001),accompanied by chronic sinusitis(=2.980,95%:1.654-5.369,=0.000),blood glucose>6.11 mmol/L(=3.219,95%:1.741-5.953,=0.000),and postoperative serum PCT>0.5 μg/L(=2.085,95%:1.106-3.931,=0.023) were independent risk factors for postoperative recurrence in CSOM patients. Effective prevention and control of MDR infection,control of blood sugar,prevention of upper respiratory tract infection,and lowering the recurrence of chronic sinusitis are the main measures to reduce postoperative recurrence of CSOM.Monitoring of the infection marker PCT can help to achieve early intervention.
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http://dx.doi.org/10.3881/j.issn.1000-503X.11203DOI Listing
February 2020

[Correlation between Asymptomatic Bacteriuria and Surgical Site Infection in Middle-aged and Elderly Patients Undergoing Open Hysterectomy].

Zhongguo Yi Xue Ke Xue Yuan Xue Bao 2019 Oct;41(5):630-635

Department of Infectious Diseases,the Third Affiliated Hospital of Guizhou Medical University,Duyun,Guizhou 558000,China.

Objective To explore the correlation between asymptomatic bacteriuria(AB)and surgical site infection(SSI)in middle-aged and elderly women undergoing open hysterectomy.Methods The clinical data of 1469 middle-aged and elderly women undergoing open hysterectomy in the Third Affiliated Hospital of Guizhou Medical University from June 2011 to August 2018 were retrospectively analyzed.Factors associated with SSI after operation were analyzed by univariate and multivariate regression models to identify the relationship of AB with SSI after open hysterectomy.Results Of these 1469 patients,101(6.88%)had SSI and 124 had AB[including 14 patients(11.29%)with infections].In addition,1345 patients had no AB,among whom 87(6.47%)had infections.Thus,the infection rate in patients with AB was significantly higher than that in patients without AB( =4.123,=0.042).Univariate analysis showed AB,history of diabetes mellitus,surgical procedure,length of stay(>15 d),season(summer and autumn),body mass index(≥25 kg/m ),nature of lesions(malignant tumors),ASA grade(>grade Ⅱ),incision length(≥10 cm),and operative time(≥3 h),bleeding volume(≥1000 ml),serum albumin concentration(<30 g/L),blood glucose(≥10 mmol/L),and hemoglobin concentration(<90 g/L)were associated with SSI(all <0.05).Multivariate analysis showed that AB,nature of lesions(malignant tumors),blood glucose(≥10 mmol/L),operative time(≥3 h),and ASA grade(>grade Ⅱ)were risk factors for SSI in these patients(all <0.05). Conclusions AB is one of the risk factors for SSI in middle-aged and elderly women undergoing open hysterectomy.Screening and treatment of AB before surgery can reduce the risk of SSI.ASA grading shall be performed before surgery before corresponding preparation was offered.Effective control of blood glucose,improved surgical skills,and shorter operative time are helpful for lowering postoperative SSI.
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http://dx.doi.org/10.3881/j.issn.1000-503X.10832DOI Listing
October 2019

Detection of New Quorum Sensing -Acyl Homoserine Lactones From .

Front Microbiol 2018 31;9:1712. Epub 2018 Jul 31.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.

Sturgeon is an important fresh water-culture fish in China. A problem with sturgeon is its high susceptibility to spoilage. Food spoilage is reported to be regulated by quorum sensing (QS). To identify the QS signals acetylated homoserine lactones (AHLs) in sturgeon and test whether QS plays a role in the spoilage of sturgeon, we investigated the specific spoilage organisms (SSOs) in vacuum packaged sturgeon stored at 4°C and the production of AHLs by sturgeon SSOs. 16S rDNA sequencing and spoilage capabilities analysis revealed that LP-11, LPJ-2, and LPC-3 were the SSOs in sturgeon. Among the three SSOs, only LP-11 induced the QS biosensors KYC55 and CV026, suggesting that it produced AHLs. Analysis by thin layer chromatography, high-performance liquid chromatography-triple quadrupole tandem mass spectrometry, and high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC/qTOF-MS) identified that the AHLs produced by were C6-SHL, C8-HSL, 3-oxo-C8-HSL, and 3-OH-C8-HSL. Our study revealed that QS system was probably involved in the regulation of sturgeon spoilage and for the first time reported the production of C8-HSL and 3-OH-C8-HSL by genus . As only HPLC/qTOF-MS effectively and accurately identified all the four AHLs produced by LP-11, this study also showed that HPLC/qTOF-MS was the most efficient method for rapid analysis of AHLs in complex microbial sample. The study provides new insight into the microbiology of sturgeon spoilage which may be helpful for better sturgeon preservation.
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http://dx.doi.org/10.3389/fmicb.2018.01712DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6079219PMC
July 2018

Effects of quorum quenching by AHL lactonase on AHLs, protease, motility and proteome patterns in Aeromonas veronii LP-11.

Int J Food Microbiol 2017 Jul 19;252:61-68. Epub 2017 Apr 19.

Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; Beijing Laboratory for Food Quality and Safety, China Agricultural University, Beijing 100083, China. Electronic address:

Food spoilage by some bacteria is reported to be regulated by quorum sensing (QS). In this study, a quorum quenching approach was used to investigate the QS regulated phenotypes (growth, protease and motility) and proteins expression in of Aeromonas veronii LP-11, which is a specific spoilage organism of sturgeon. AHL lactonase AiiA from Bacillus quenched the QS system, probably by enzymatically inactivating the AHLs produced by A. veronii LP-11. After AiiA treatment, the protease and motility activities of A. veronii LP-11 were reduced, but cell growth was not affected. Proteome analysis revealed thirty-two proteins that were differentially expressed within cells treated with AiiA at early stationary phase, and that are functionally involved in metabolite transport, amino acid metabolism, central metabolism, respiration, transcription and translation, suggesting that QS may globally coordinate the metabolic processes within A. veronii LP-11 cells. Some of these QS regulated proteins were identified to be potentially participated in nutrient acquirement from environment and spoilage behavior of the organism. Indeed, AiiA treatment inhibited the spoilage progress of vacuum-packaged sturgeon stored at 4°C. These results highlight that the QS is a major metabolism regulator within A. veronii LP-11 cells and participates in sturgeon spoilage.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2017.04.005DOI Listing
July 2017

Chemical characteristics and antithrombotic effect of chondroitin sulfates from sturgeon skull and sturgeon backbone.

Carbohydr Polym 2015 Jun 3;123:454-60. Epub 2015 Feb 3.

Beijing Laboratory of Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China. Electronic address:

Chondroitin sulfates (CSs) were extracted from sturgeon skull and backbone, and their chemical composition, anticoagulant, anti-platelet and thrombolysis activities were evaluated. The average molecular weights of CS from sturgeon skull and backbone were 38.5kDa and 49.2kDa, respectively. Disaccharide analysis indicated that the sturgeon backbone CS was primarily composed of disaccharide monosulfated in position four of the GalNAc (37.8%) and disaccharide monosulfated in position six of the GalNAc (59.6%) while sturgeon skull CS was primarily composed of nonsulfated disaccharide (74.2%). Sturgeon backbone CS showed stronger antithrombotic effect than sturgeon skull CS. Sturgeon backbone CS could significantly prolong activated partial thromboplastin time (APTT) and thrombin time (TT), inhibited ADP-induced platelet aggregation and dissolved platelet plasma clots in vitro. The results suggested that sturgeon backbone CS can be explored as a functional food with antithrombotic function.
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http://dx.doi.org/10.1016/j.carbpol.2015.01.046DOI Listing
June 2015

Rheological, emulsifying and thermostability properties of two exopolysaccharides produced by Bacillus amyloliquefaciens LPL061.

Carbohydr Polym 2015 Jan 27;115:230-7. Epub 2014 Aug 27.

Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, 17# Qinghua East Road, Beijing, China. Electronic address:

The rheological, emulsification, thermostability and certain physicochemical properties of two purified exopolysaccharides from Bacillus amyloliquefaciens LPL061 were studied. EPS1 showed entangled spider mesh structure that composed of dense rope with homogeneous hexagonal particles under scanning electron microscopy. EPS2 had a porous sponge structure with uniform cylindrical particles. The two exopolysaccharides showed higher intrinsic viscosity and better emulsification activity with sunflower seed oil, rice oil, olive oil and peanut oil compared to guar gum. EPS1 is the most promising one for applications in the industry, as it had high intrinsic viscosity, apparent viscosity and thermostablity in aqueous solution, dense entangled structure and good emulsification activity.
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http://dx.doi.org/10.1016/j.carbpol.2014.08.044DOI Listing
January 2015

Paraplantaricin L-ZB1, a novel bacteriocin and its application as a biopreservative agent on quality and shelf life of rainbow trout fillets stored at 4 °c.

Appl Biochem Biotechnol 2014 Nov 2;174(6):2295-306. Epub 2014 Sep 2.

College of Food Science and Nutritional Engineering, China Agricultural University, NO. 17 Qinghua East Road, East Campus, Haidian District, Beijing, 100083, China,

Paraplantaricin L-ZB1 was produced by Lactobacillus paraplantarum L-ZB1, which was isolated from the traditional China fermented sausage. In this work, paraplantaricin L-ZB1 was used to maintain quality of rainbow trout fillets at 4 °C. Rainbow trout fillets were left untreated (CK) or treated with 200 activity units (AU)/ml paraplantaricin L-ZB1 (P1), 400 AU/ml paraplantaricin L-ZB1 (P2) or 200 AU/ml Nisin (N). The treated samples were stored at 4 °C for up to 10 days, and the quality changes were determined by microbiological (total viable count [TVC], Enterobacteriaceae, Pseudomonas, spore-forming bacteria), sensory, chemical (pH, total volatile basic nitrogen [TVB-N]) and biochemical (biogenic amines, K value) methods. Results show that paraplantaricin L-ZB1 could inhibit the growth of microflora, especially Enterobacteriaceae, Pseudomonas and spore-forming bacteria during sample storage. Meanwhile, the increases of pH, TVB-N, K value and biogenic amine levels were significantly delayed in paraplantaricin L-ZB1-treated samples compared to the control group. Paraplantaricin L-ZB1 of 400 AU/ml extended the rainbow trout fillets' shelf life to 4-6 days, and the sample showed good sensory characteristics. Therefore, paraplantaricin L-ZB1 could be used as a suitable biological preservative for chilled rainbow trout fillets.
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http://dx.doi.org/10.1007/s12010-014-1160-3DOI Listing
November 2014

Biogenic amines formation, nucleotide degradation and TVB-N accumulation of vacuum-packed minced sturgeon (Acipenser schrencki) stored at 4 °C and their relation to microbiological attributes.

J Sci Food Agric 2014 Aug 29;94(10):2057-63. Epub 2014 Jan 29.

Beijing Laboratory for Food Quality and Safety, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing, 100083, China.

Background: Sturgeon (Acipenser schrencki) were filleted, minced, vacuum-packed and stored at 4 °C. Minced sturgeon muscles were analysed for 10 days to determine biochemical [eight biogenic amines, ATP and breakdown products, K value, total volatile basic nitrogen (TVB-N) and pH], microbiological (total viable counts, Enterobacteriaceae, Psychrotrophs, Pseudomonas, Aeromonas, Vibrio, Lactobacillus and Brochothrix thermosphacta) changes and their relationships.

Results: The shelf-life of sturgeon was found to be 3-4 days according to microbiological assessment. At the end of the storage, Psychrotrophs, Enterobacteriaceae and Aeromonas became the dominant bacteria, reaching 7.85, 7.98 and 8.02 log cfu g(-1), respectively. Biogenic amines, hypoxanthine and the K value increased significantly (P < 0.05) during the storage. Putrescine and cadaverine was the dominant biogenic amines while tryptamine was not detected during the storage. In addition, putrescine, cadaverine and hypoxanthine were highly related to storage time and total viable counts (r(2), 0.876-0.962), indicating that they can be good biomarkers for quality assessment of vacuum-packed minced sturgeon stored at 4 °C.

Conclusion: In this study, key biochemical and microbiological attributes were established to monitor the spoilage and shelf life of vacuum-packed sturgeon. These results could help to establish better cold storage management of minced sturgeon products under commercial conditions.
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http://dx.doi.org/10.1002/jsfa.6524DOI Listing
August 2014

Effect of combined function of temperature and water activity on the growth of Vibrio harveyi.

Braz J Microbiol 2012 Oct 1;43(4):1365-75. Epub 2012 Jun 1.

College of Food Science, Sichuan Agricultural University , Yaan, 625014 , China ; Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science & Nutritional Engineering, China Agricultural University , Beijing, 100083 , China.

Vibrio harveyi is considered as a causative agent of the systemic disease, vibriosis, which occurs in many biological fields. The effects of temperatures (12.9-27.1 °C) and water activity (NaCl% 0.6%-3.4%) on V. harveyi were investigated. The behavior and growth characteristics of V. harveyi was studied and modeled. Growth curves were fitted by using Gompertz and Baranyi models, and the Baranyi model showed a better fittness. Then, the maximum growth rates (μmax) and lag phase durations (LPD, λ) obtained from both Gompertz and Baranyi model were modeled as a combination function of temperature and water activity using the response surface and Arrhenius-Davey models for secondary model. The value of r(2), MSE, bias and accuracy factor suggest Baranyi model has better fitness than Gompertz model. Furthermore, validation of the developed models with independent data from ComBase also shown better interrelationship between observed and predicted growth parameter when using Baranyi model.
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http://dx.doi.org/10.1590/S1517-838220120004000018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3769047PMC
October 2012

Role of plnB gene in the regulation of bacteriocin production in Lactobacillus paraplantarum L-XM1.

Microbiol Res 2013 Jun 28;168(5):305-10. Epub 2012 Dec 28.

Key Lab of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.

Homologues of plnB gene have been shown to participate in regulation of bacteriocin production through quorum sensing system in other organisms, to investigate the possible role of plnB gene in Lactobacillus paraplantarum L-XM1, we cloned and insertionally inactivated the plnB gene. The plnB knockout mutant ΔplnB21 showed loss of bacteriocin production, its Bac⁺ phenotype could not be restored even after the addition of PlnA. Furthermore, reverse transcription-PCR analysis from total RNA preparations showed that the bacteriocin structural genes of the plnEF and plnJK were not transcribed in the plnB knockout mutant compared with the wild-type strain. It was therefore concluded that plnB is invovled in a quorum sensing based bacteriocin production. This is the first demonstration of a role for plnB by gene knockout in L. paraplantarum.
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http://dx.doi.org/10.1016/j.micres.2012.11.008DOI Listing
June 2013

[Researches on the effect of gas humidity on photoacoustic spectroscopy gas detection system].

Guang Pu Xue Yu Guang Pu Fen Xi 2011 Jul;31(7):1819-22

School of Information Engineering, Southwest University of Science and Technology, Mianyang 621000, China.

Environmental influence is the important factor in a photoacoustic spectroscopy gas detection (PASGD) system when it is applied in the industrial field. The experiments show that the sensitivity of condenser microphone is affected mostly by the humidity of the gas under test, leading to the PASGD's result drift. The present paper puts forward a method to eliminate the influence of gas humidity. A speaker is fixed in the photoacoustic cell, whose amplitude is regarded as the sensitivity self-adaption characterization of sound sensor, used to correct the photoacoustic signal amplitude. Thus the problem of sensitivity changing in sound detection with condenser microphone is solved. Based on this method, a photoacoustic experimental setup, equipped with a diode laser, a resonant photoacoustic cell and a lock-in amplifier, was applied to compare the test for different humidity samples. The results show that this method is useful to eliminating the gas humidity influence and enhancing environmental adaptability of PASGD system.
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July 2011

[Theoretical study on radial resonance coupling of cylindrical photoacoustic cells].

Guang Pu Xue Yu Guang Pu Fen Xi 2010 Apr;30(4):879-82

College of National Defense, Southwest University of Science and Technology, Mianyang 621000, China.

Photoacoustic detection of trace concentrations of gases is one of the most sensitive techniques of infrared absorption spectroscopy. High-sensitivity photoacoustic detectors apply an acoustic resonator for the amplification of the weak photoacoustic signal. If the modulation frequency coincides with one of the resonance frequencies of the chamber, a standing acoustic wave is excited and the system works as an acoustic amplifier. The amplification of the resonator relies on the acting mode, quality factor, nature of microphone, and the coupling between electromagnetic radiation and the stand wave resonance mode. With different incidence orientation of the modulated IR laser relative to acoustic chamber, the sound pressure magnitude of resonance mode varies. The influence of different laser incidence orientation on the coupling coefficients of radial resonance mode of cylindrical photoacoustic cells was investigated by both theoretical deduction and numerical computation method. It is concluded that the coupling coefficients have two zeros and two maximums when the laser incidence angle varies from 0 to pi/2. When the incidence angle is 0 or tan(-1) (0.859 2 X 2R/L), the coupling coefficients are zeros and the radial resonance is invalid. When the incidence angle is tan(-1) (0.556 8 X 2R/L) or tan(-1) (2R/L), the coupling coefficients are the maximums and the radial resonance is the strongest. Here R is the radius and L the length of the cell. The results therein before give some theoretical guidelines for photoacoustic cell designing, optimizing, installing and adjusting, and for improvement of detection sensitivity in trace gas detectors through maximal excitement of radial modes in cylindrical acoustic cells.
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April 2010
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