Three Bacteriocin Peptides from a Lactic Acid Bacterium Weissella confusa MBF8-1 with Spermicidal Activity

Background:The development of antibiotic resistance amongst bacterial pathogens and a population explosion, e.g. in countries such as Indonesia, are two issues the world is facing today. These issues have stimulated interest in the development of new antimicrobial therapeutic agents and contraceptive strategies, such as novel spermicides. Bacteriocins, which are bacterially-derived antimicrobial peptides, may fulfill some of the criteria for these new agents.Methods:Weissella confusa MBF8-1, originally isolated from a homemade soy product, exhibits antibacterial activity that was subsequently found to be plasmid-encoded, presumably by three peptides Bac1, Bac2 and Bac3. In the present study, we tested cell-free MBF8-1 bacteriocin preparations and chemically-synthesized versions of Bac1, Bac2 and Bac3 peptides for (i) its antibacterial activity against the indicator bacterium Leuconostoc mesenteroides and (ii) its ability to affect the motility of spermatozoa. Nisin, a known lantibiotic bacteriocin, was used as the control.Results:Here, we demonstrate that synthetic Bac1, in combination with synthetic Bac2, was sufficient to inhibit the growth of L. mesenteroides and affect sperm motility. However, the presence of all three synthetic peptides, s-Bac1, s-Bac2 and s-Bac3, was required for full potency.Conclusion:In summary, the bacteriocin-like peptides of W. confusa MBF8-1 have the potential to be developed as a narrow-spectrum antimicrobial agent and a novel spermicidal agent.

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Selection and characterization of potential probiotic Lactobacilli spp isolated from chicken feces may be used as a potent antibacterial agent

Asian Journal of Dairy and Food Research ◽

10.18805/ajdfr.v35i1.9252 ◽

2016 ◽

Vol 35 (1) ◽

Author(s):

Nazila Aazami ◽

Enayatollah Kalantar ◽

Helen Poormazaheri ◽

Nassimeh Setayesh vali Pour ◽

Gholamreza Salehi Jouzan

Keyword(s):

Antibacterial Activity ◽

Antibiotic Resistance ◽

Lactic Acid ◽

Lactic Acid Bacteria ◽

Acid Tolerance ◽

Resistance Test ◽

Effect Of Temperature ◽

Rdna Sequencing

<italic>Lactobacillus</italic> strains commonly used as probiotics which possess some properties such as resistance to gastric acidity and bile salts, production of antimicrobial compounds, the ability to modulate immune responses, and adhesion to gut tissues. This study aimed to isolate, identify, production and characterization of the probiotic strains. Total of 10 digestive tracts of chickens fed without antibiotics for presence of <italic>Lactobacillus spp</italic> was evaluated. All isolates were grown with different conditions like effect of temperature, pH, pepsine, bile, sodium chloride tolerance, aggregation, adhesion and antibiotic resistance test tested and then antibacterial activity was determined.In this study, 34 lactic acid bacteria were investigated as putative probiotic candidates. Based on the molecular identification using 16S rDNA sequencing the isolates belonged to <italic>Lactobacillus</italic> species. The strains showed potent antibacterial activity. The results on acid tolerance showed that all the strains tested survived at pH 2.0 to 5.5. <italic>L. agilis</italic> strain M18, <italic>L. salivarius</italic> strain M10, <italic>L.vaginalis</italic> strains M8 and M19, and <italic>L. crispatus</italic> strains Or2 and M10 showed the lowest sensitivity to pepsine. All the studied Lactobacillus strains were able to grow at both 15 and 45°C . Five Lactobacillus strains adhered well to the Caco-2 cells. The result of antibiotic resistance test of 34 lactic acid bacteria showed that most of them were resistant or intermediate. Based on 34 <italic>Lactobacillus</italic> strains, <italic>L. vaginalis</italic> strain M8 and <italic>L. reuteri</italic> strain M6 were selected for the further in vivo assays and possible eventual use as prophylactic and therapeutic agent.

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Nanocomposites based on biocompatible polymers and graphene oxide for antibacterial coatings

Polymers and Polymer Composites ◽

10.1177/09673911211020601 ◽

2021 ◽

pp. 096739112110206

Author(s):

Fika Fauzi ◽

Muhammad Miqdam Musawwa ◽

Habibi Hidayat ◽

Ahmad Kusumaatmaja ◽

Wipsar Sunu Brams Dwandaru

Keyword(s):

Antibacterial Activity ◽

Graphene Oxide ◽

Lactic Acid ◽

Essential Oils ◽

Vinyl Alcohol ◽

Poly Lactic Acid ◽

Poly Vinyl Alcohol ◽

Biocompatible Polymers ◽

Antibacterial Coatings ◽

The World

Recently, antibacterial coatings based on graphene oxide (GO) nanocomposites have attracted many studies around the world. The use of polymers as the matrices of GO nanofillers in the nanocomposites has been explored to produce efficient coatings against bacteria. One of the most prospective applications is the incorporation of GO into biocompatible polymers, which can produce antibacterial coatings. Here, recent progresses on the antibacterial coatings of nanocomposites based on biocompatible polymers and GO are reviewed. The effect of GO filler concentrations, biocide materials, and biocompatibility are discussed to find the most efficient antibacterial activity and biocompatibility of nanocomposites. Among biocompatible polymers, chitosan (Cs), poly vinyl alcohol (PVA), and poly lactic acid (PLA) are the most popular matrices used for the nanocomposites. This review also elaborates challenges in the use of other biocompatible polymers. Future works on biocompatible antibacterial coatings should be conducted by considering the concentration of GO nanofillers or adding other materials such as essential oils to suppress the toxicity toward functional cells.

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Antibacterial Activity of Lactic Acid Producing Leuconostoc mesenteroides QZ1178 Against Pathogenic Gallibacterium anatis

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.630294 ◽

2021 ◽

Vol 8 ◽

Author(s):

Hua Zhang ◽

HePing HuangFu ◽

Xing Wang ◽

ShanShan Zhao ◽

Yuan Liu ◽

...

Keyword(s):

Electron Microscopy ◽

Antibacterial Activity ◽

Lactic Acid ◽

Leuconostoc Mesenteroides ◽

Cell Damage ◽

Fermented Food ◽

Economic Losses ◽

Transmission Electron ◽

Extensive Cell ◽

Different Origins

Lactic acid bacteria (LAB) convert carbohydrates into organic acids [mainly lactic acid (LA)], which reportedly have bactericidal activities. Gallibacterium anatis is a Gram-negative bacteria which infects birds, and causes significant economic losses. In this study, we investigated the antibacterial activity of the LA producing, Leuconostoc mesenteroides QZ1178 from Qula (fermented food), against G. anatis, using the Oxford cup method. Our data showed that L. mesenteroides QZ1178 inhibited G. anatis isolates from different origins; however, L. mesenteroides QZ1178 antibacterial activity dropped dramatically at pH 5.5–pH 6. The LA concentration and pH of the liquid broth containing L. mesenteroides QZ1178 after 24 h culture was 29 mg/mL and 3.6, respectively. This concentration (29 mg/mL at pH 3.6) and the antibiotic, cefotaxime (minimum inhibitory concentration (MIC) 2.5 μg/mL) effectively inhibited G. anatis (GAC026) growth as observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Gallibacterium anatis treated with LA exhibited extensive cell surface collapse, increased cell damage, cell membrane disruption, and cytoplasmic leakage, indicative of cell lysis. We suggest L. mesenteroides QZ1178 exerts potential antibacterial effects against the poultry pathogen, G. anatis via LA.

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Brewers’ spent grain as substrate for dextran biosynthesis by Leuconostoc pseudomesenteroides DSM20193 and Weissella confusa A16

Microbial Cell Factories ◽

10.1186/s12934-021-01515-4 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Prabin Koirala ◽

Ndegwa Henry Maina ◽

Hanna Nihtilä ◽

Kati Katina ◽

Rossana Coda

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Raw Materials ◽

Degree Of Polymerization ◽

Raw Material ◽

Fermentation Time ◽

Viscosity Increase ◽

Spent Grain ◽

Leuconostoc Pseudomesenteroides ◽

Weissella Confusa

Abstract Background Lactic acid bacteria can synthesize dextran and oligosaccharides with different functionality, depending on the strain and fermentation conditions. As natural structure-forming agent, dextran has proven useful as food additive, improving the properties of several raw materials with poor technological quality, such as cereal by-products, fiber-and protein-rich matrices, enabling their use in food applications. In this study, we assessed dextran biosynthesis in situ during fermentation of brewers´ spent grain (BSG), the main by-product of beer brewing industry, with Leuconostoc pseudomesenteroides DSM20193 and Weissella confusa A16. The starters performance and the primary metabolites formed during 24 h of fermentation with and without 4% sucrose (w/w) were followed. Results The starters showed similar growth and acidification kinetics, but different sugar utilization, especially in presence of sucrose. Viscosity increase in fermented BSG containing sucrose occurred first after 10 h, and it kept increasing until 24 h concomitantly with dextran formation. Dextran content after 24 h was approximately 1% on the total weight of the BSG. Oligosaccharides with different degree of polymerization were formed together with dextran from 10 to 24 h. Three dextransucrase genes were identified in L. pseudomesenteroides DSM20193, one of which was significantly upregulated and remained active throughout the fermentation time. One dextransucrase gene was identified in W. confusa A16 also showing a typical induction profile, with highest upregulation at 10 h. Conclusions Selected lactic acid bacteria starters produced significant amount of dextran in brewers’ spent grain while forming oligosaccharides with different degree of polymerization. Putative dextransucrase genes identified in the starters showed a typical induction profile. Formation of dextran and oligosaccharides in BSG during lactic acid bacteria fermentation can be tailored to achieve specific technological properties of this raw material, contributing to its reintegration into the food chain.

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Hardening Properties of Cheeses by Latilactobacillus curvatus PD1 Isolated from Hardened Cheese-Ddukbokki Rice Cake

Microorganisms ◽

10.3390/microorganisms9051044 ◽

2021 ◽

Vol 9 (5) ◽

pp. 1044

Author(s):

Jeong A Kim ◽

Geun Su Kim ◽

Se Mi Choi ◽

Myeong Seon Kim ◽

Do Young Kwon ◽

...

Keyword(s):

Lactic Acid ◽

Lactic Acid Bacteria ◽

Acid Production ◽

Lactobacillus Casei ◽

Leuconostoc Mesenteroides ◽

The Other ◽

Rice Cake ◽

Two Samples ◽

High Protease Activity

Hardening of cheese is one of major issues that degrade the quality of Home Meal Replacement (HMR) foods containing cheese such as Cheese-ddukbokki rice cake (CD, stir-fried rice cakes with shredded cheese). The quality of cheese, such as pH, proteolytic, and flavor properties, depends on various lactic acid bacteria (LAB) used in cheese fermentation. The hardening of cheese is also caused by LAB. In this study, various LAB strains were isolated from CD samples that showed rapid hardening. The correlation of LAB with the hardening of cheese was investigated. Seven of the CD samples with different manufacturing dates were collected and tested for hardening properties of cheese. Among them, strong-hardening of cheese was confirmed for two samples and weak-hardening was confirmed for one sample. All LAB in two strong-hardening samples and 40% of LAB in one weak-hardening sample were identified as Latilactobacillus curvatus. On the other hand, most LAB in normal cheese samples were identified as Leuconostoc mesenteroides and Lactobacillus casei. We prepared cheese samples in which L. curvatus (LC-CD) and L. mesenteroides (LM-CD) were most dominant, respectively. Each CD made of the prepared cheese was subjected to quality test for 50 days at 10 °C. Hardening of cheese with LC-CD dominant appeared at 30 days. However, hardening of cheese with LM-CD dominant did not appear until 50 days. The pH of the LC-CD was 5.18 ± 0.04 at 30 days, lower than that of LM-CD. The proteolytic activity of LC-CD sample was 2993.67 ± 246.17 units/g, higher than that of LM-CD sample (1421.67 ± 174.5 units/g). These results indicate that high acid production and high protease activity of L. curvatus might have caused hardening of cheese.

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Lactobacillus reuteri BM53-1 Produces a Compound That Inhibits Sticky Glucan Synthesis by Streptococcus mutans

Microorganisms ◽

10.3390/microorganisms9071390 ◽

2021 ◽

Vol 9 (7) ◽

pp. 1390

Author(s):

Masafumi Noda ◽

Naho Sugihara ◽

Yoshimi Sugimoto ◽

Ikue Hayashi ◽

Sachiko Sugimoto ◽

...

Keyword(s):

Antibacterial Activity ◽

Lactic Acid ◽

Dental Caries ◽

Lactobacillus Reuteri ◽

Early Stage ◽

Pcr Analysis ◽

Cariogenic Bacteria ◽

Qrt Pcr ◽

Actinidia Polygama ◽

Glucan Synthesis

Cariogenic bacteria, such as Streptococcus (S.) mutans and S. sobrinus, produce insoluble and sticky glucans as a biofilm material. The present study demonstrates that a lactic acid bacterium (LAB) named BM53-1 produces a substance that inhibits the sticky glucan synthesis. The BM53-1 strain was isolated from a flower of Actinidia polygama and identified as Lactobacillus reuteri. The substance that inhibits sticky glucan synthesis does not exhibit antibacterial activity against S. mutans. The cariogenic S. mutans produces glucans under the control of three glucosyltransferase (GTF) enzymes, named GtfB, GtfC, and GtfD. Although GtfB and GtfC produce insoluble glucans, GtfD forms soluble glucans. Through quantitative reverse-transcriptional (qRT)-PCR analysis, it was revealed that the BM53-1-derived glucan-production inhibitor (GI) enhances the transcriptions of gtfB and gtfC genes 2- to 7-fold at the early stage of cultivation. However, that of gtfD was not enhanced in the presence of the GI, indicating that the glucan stickiness produced by S. mutans was significantly weaker in the presence of the GI. Our result demonstrates that Lb. reuteri BM53-1 is useful to prevent dental caries.

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Potential impact of biocide adaptation on selection of antibiotic resistance in bacterial isolates

Future Journal of Pharmaceutical Sciences ◽

10.1186/s43094-020-00119-w ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Engy Elekhnawy ◽

Fatma Sonbol ◽

Ahmed Abdelaziz ◽

Tarek Elbanna

Keyword(s):

Antibiotic Resistance ◽

Cross Resistance ◽

Main Body ◽

Bacterial Isolates ◽

New Agents ◽

Biocidal Products ◽

Potential Impact ◽

Emergence Of Resistance ◽

Vital Factor ◽

Selection Of

Abstract Background Antibiotic resistance in pathogenic bacterial isolates has increased worldwide leading to treatment failures. Main body Many concerns are being raised about the usage of biocidal products (including disinfectants, antiseptics, and preservatives) as a vital factor that contributes to the risk of development of antimicrobial resistance which has many environmental and economic impacts. Conclusion Consequently, it is important to recognize the different types of currently used biocides, their mechanisms of action, and their potential impact to develop cross-resistance and co-resistance to various antibiotics. The use of biocides in medical or industrial purposes should be monitored and regulated. In addition, new agents with biocidal activity should be investigated from new sources like phytochemicals in order to decrease the emergence of resistance among bacterial isolates.

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Novel Seleno- and Thio-Urea Containing Dihydropyrrol-2-One Analogues as Antibacterial Agents

Antibiotics ◽

10.3390/antibiotics10030321 ◽

2021 ◽

Vol 10 (3) ◽

pp. 321

Author(s):

Shekh Sabir ◽

Tsz Tin Yu ◽

Rajesh Kuppusamy ◽

Basmah Almohaywi ◽

George Iskander ◽

...

Keyword(s):

Antibacterial Activity ◽

Antibiotic Resistance ◽

Quorum Sensing ◽

Antibacterial Agents ◽

Inhibitory Concentration ◽

Resistant Bacteria ◽

Drug Resistant ◽

Positive Bacterium ◽

Quorum Sensing Inhibition ◽

Drug Resistant Bacteria

The quorum sensing (QS) system in multi-drug-resistant bacteria such as P. aeruginosa is primarily responsible for the development of antibiotic resistance and is considered an attractive target for antimicrobial drug discovery. In this study, we synthesised a series of novel selenourea and thiourea-containing dihydropyrrol-2-one (DHP) analogues as LasR antagonists. The selenium DHP derivatives displayed significantly better quorum-sensing inhibition (QSI) activities than the corresponding sulphur analogues. The most potent analogue 3e efficiently inhibited the las QS system by 81% at 125 µM and 53% at 31 µM. Additionally, all the compounds were screened for their minimum inhibitory concentration (MIC) against the Gram-positive bacterium S. aureus, and interestingly, only the selenium analogues showed antibacterial activity, with 3c and 3e being the most potent with a MIC of 15.6 µM.

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