Bacteriocin Concentration Research Articles

Purification Of Bacteriocin Produced By Staphylococcus Aureus And Its Effect On Some Candida Spp.

Candida is the most implicated fungal pathogen in the clinical setting. Virulence factors, such as biofilms play important roles in its pathogenesis. Hence, this study aimed to investigate role of staphylococcal bacteriocin in inhibit biofilm and viability of Candida spp. Seventy-two isolates were collected from abscess, wounds and burns . All isolates were reidentified using different examinations. In addition, eight species of previously isolated clinical Candida species, from oral and vaginal cavities of patients with candidiasis, including C. albicans, C. glabrata, C. parasilosis, C. krusei, C. lusitaniae, C. kefyr, C. tropicalis and C. ciferrii, were utilized to check the antimicrobial activity of S. aureus on Candida spp. Agar well diffusion method were used to detect bacteriocin production by S. aureus, whereas only 5 isolates were selected. The antibacterial effect of selected S. aureus isolates were tested against indicators (Pseudomonas aeruginosa, Escherichia coli and Candida albicans). Isolate of S. aureus no.2 was showed the best bacteriocin production. Bacteriocin was purified using ammonium sulfate and dialysis. Different concentrations was utilized to determine sub-minimal inhibitory concentration (sub-MIC) of bacteriocin. Sub-MIC of bacteriocin was utilized to estimate its inhibitory effect on viability of Candida spp. Bacteriocin showed the maximal inhibition percentage against C. parapsilosis CV26 with 85.42%, followed by C. tropicalis CO49 with 80.49%. The viability of C. kefyr CO45, C. krusei CO41, C. glabrata CO38, C. albicans CV5 and C. lusitaniae was inhibited by 77.78, 75.41, 74.67, 71.43 and 70.18%, respectively. In addition, 69.84 and 64.62% of C. albicans CV1 and C. ciferrii. Using microtiter plate, sub-MIC of bacteriocin showed maximal inhibitory effect against C. ciferrii with 82.26%, followed by C. lusitaniae with 80.4%, the biofilm formation of C. parapsilosis CV26 and C. tropicalis CO49 was inhibited by 80.49% and 79.82%, respectively.

Discovery and Characterization of a Novel Bacteriocin That Strongly Inhibits Staphylococcus aureus

Drug resistance in Staphylococcus aureus is a serious problem, and the development of new antimicrobial drugs to circumvent drug resistance has become a trend. In this study, we isolated a strain of Bacillus subtilis with high tolerance to alcohol, pH, NaCl, bile salt, surfactants, temperature, and simulated intestinal fluids. We optimized culture parameters to obtain the best fermentation conditions for the production of inhibitory compounds in cell-free culture media. The crude extract showed excellent stability when exposed to temperature, pH, and ultraviolet radiation, with almost no loss of bacteriostatic activity after treatment. After isolation and purification, the peptide sequences were identified using ultraperformance liquid chromatography–mass spectrometry (UPLC–MS), and the antibacterial sequences were analyzed using bioinformatics. The results of the identification showed that there was one novel bacteriocin (NSGGSYGSGGGGGGGNSHGY) with a molecular weight of 1513.58 Da. The minimum inhibitory concentration (MIC) of the B5 bacteriocin was 31.25 μg/mL against S. aureus, and it is noteworthy that bacteriocin B5 also showed weak antibacterial activity against Vibrio parahaemolyticus. In conclusion, this study developed a novel bacteriocin that has the potential to be used as an alternative to S. aureus antibiotics.

Potential biological active bacteriocin production by Bifidobacterium via eco‐friendly, low‐cost solid state fermentation principle

AbstractThe present study is undertaken to evaluate the potential biological activities of bacteriocin produced by the Lactic acid bacteria Bifidobacterium sp. adopting solid state fermentation. Bifidobacterium was isolated from cooked fermented rice water. Isolated bacterial strain was identified by morphological, biochemical, and molecular characteristics. Sterilized cooked rice was inoculated with bacterial inoculum followed by extraction of bacteriocin under aseptic condition. Extracted bacteriocin was screened for antibacterial, antioxidant, and anti‐inflammatory activities under invitro condition. Cooked fermentation rice medium used for solid state fermentation (SSF) supported growth and bacteriocin production by Bifidobacterium longum. Potential antibacterial activity of the extracted bacteriocin was confirmed by growth inhibition of Bacillus subtilis, and Escherichia coli strain. Notable free radical scavenging activity at 120 μg/mL concentration of bacteriocin clearly indicated antioxidant activity. Anti‐inflammatory activity of the bacteriocin was determined which showed maximum inhibition at 120 μg/mL concentration. All these finding suggest the possible utilization of bacteriocin extraction from Bifidobacterium as an effective, safe bioactive agent.

Sensitivity of Salmonella Typhimurium to nisin in vitro and in orange juice under refrigeration.

The influence of environmental factors on Salmonella sensitivity to nisin in vitro and in refrigerated orange juice were investigated. Nisin activity was observed in the different conditions, but the highest efficiency was achieved at lower pH (4.0) and with higher bacteriocin concentration (174µM). Moreover, the bactericidal action was directly proportional to the incubation period. When tested in orange juice, nisin caused a reduction of up to 4.05 logarithm cycles in the Salmonella population. So, environmental factors such as low pH and low temperature favored the sensitization of Salmonella cells to the bactericidal action of nisin. Therefore, this may represent an alternative to control Salmonella in refrigerated foods.

Effect of adding bacteriocin from Lactobacillus pentosus strain MIL 195 on the quality of chicken sausage as an alternative natural preservative

One of the preservatives often used in processed meat, such as sausages, is nitrite; however, bacteriocins produced by lactic acid bacteria (LAB) offer a natural concentration of bacteriocin from Lactobacillus pentosus st MIL 195 to use as a natural preservative for chicken sausages. A completely randomized design was employed with five bacteriocin concentrations (0.0%, 0.2%, 0.3%, 0.4%, and 0.5% v/w) and three replications. Parameters analyzed included water content, ash, fat, protein, total LAB count, and sensory characteristics. The results indicated that 0.4% bacteriocin provided the most effective preservation. After nine days, these sausages met SNI-01-3820-2015 quality standards, exhibiting 57.52% water content, 2.54% ash, 15.40% protein, 5.55% fat, and a total microbial count of 5.23 log cfu.g-1. Sensory analysis revealed a grayish-white color, a slightly chicken aroma, a slightly meaty taste, and a chewy texture. Importantly, consumer preference was highest for sausages treated with 0.4% bacteriocin. Bacteriocins can inhibit the growth of spoilage bacteria; therefore, the effect can extend the shelf life of food goods and improve food security.

Complete Genome Sequencing and Bacteriocin Functional Characterization of Pediococcus ethanolidurans CP201 from Daqu.

This study aims to sequence the whole genome of Pediococcus ethanolidurans CP201 isolated from Daqu and determine the anti-corrosion ability of bacteriocins on chicken breast. The whole genome sequence information of P. ethanolidurans CP201 was analyzed, and its gene structure and function were explored. It was found that gene1164 had annotations in the NR, Pfam, and Swiss-Prot databases, and was related to bacteriocins. The exogenous expression of the bacteriocin gene Pediocin PE-201 was analyzed based on the pET-21b vector and the host BL21, and the corresponding bacteriocin was successfully expressed under the induction of IPTG. After purification by NI-NTA column, enterokinase treatment, membrane dialysis concentration treatment, and SDS-PAGE electrophoresis, the molecular weight was about 6.5kDa and the purity was above 90%. By applying different concentrations of bacteriocin to chicken breast with different levels of contamination, the control of pathogenic bacteria, the ordinary contamination level (OC) group, and the high contamination level (MC) group could be completely achieved with 25mg/L bacteriocin. In conclusion, the bacteriocin produced by the newly isolated CP201 can be applied to the preservation of meat products to prevent the risk of food-borne diseases.

Electrospun plant protein-based nanofibers loaded with sakacin as a promising bacteriocin source for active packaging against Listeria monocytogenes in quail breast

The main objective of this study was to fabricate nanofibers from zein incorporated with two concentrations of sakacin (9 and 18 AU/mL) with anti-Listeria properties by electrospinning technique. The efficacies of the resulting active nanofibers against L. innocua, in quail breast during 24 days of refrigerated storage (4 ± 1 °C) were evaluated. The minimum inhibitory concentration (MIC) of bacteriocin against L. innocua was approximate 9 AU/mL. Fourier-transform infrared spectra of bacteriocin-loaded nanofibers indicated characteristic peaks of zein and sakacin and that the nanofibers showed an encapsulation efficiency close to 91.5 %. The thermal stability of sakacin increased by electrospinning. Scanning electron microscopy images showed that nanofibers prepared from electrospinning zein/sakacin solutions exhibited smooth and continuous nanofibers with no defects with an average diameter between 236 and 275 nm. The presence of sakacin led to decreased contact angle properties. Nanofibers with 18 AU/mL sakacin exhibited the highest zone of inhibition of 226.14 ± 8.05 mm. The lowest L. innocua (6.1 logs CFU/cm2) growth after 24 days at 4 °C were obtained in quail breast wrapped with zein containing 18 AU/mL sakacin. The results demonstrate an outlook for the potential use of zein nanofibers containing sakacin to reduce L. innocua contamination in ready-to-eat (RTE) products.

Bacteriocin production by Lactococcus lactis LL‐HSTU‐FPP strain isolated from fermented rice and evaluation of the biopreservation potentiality of bacteriocin on shrimp

AbstractLactococcus lactis LL‐HSTU‐FPP was isolated from fermented rice and bacteriocin produced by this strain was used to investigate the antagonistic properties against foodborne pathogens. Subsequently, different concentrations (7.5 and 10%, v/v) of bacteriocin were applied to shrimp to analyze the spoilage rates during refrigerated storage. The isolate LL‐HSTU‐FPP was characterized using different biochemical tests (Catalase, bile esculin) and identified by 16S rRNA gene sequencing. Fourier transform infrared spectroscopy (FTIR) was conducted to assess the amide group in the bacteriocin produced by the strain LL‐HSTU‐FPP. The bacteriocin exhibited better inhibitory effect than the antibiotic ciprofloxacin against Escherichia coli, Vibrio cholera, and Staphylococcus aureus strains. Furthermore, the bacteriocin retained its activity after treatment with high temperatures ranging from 40 to 121°C, in a wide pH range (2–9), and after treatment with different enzymes. However, the tendency to reduce spoilage microorganisms in shrimp as a consequence of the bacteriocin effect was significant compared to the control and the sample treated with 1% acetic acid after storage. As a result, the 10% concentration of bacteriocin used for the treatment of shrimps was shown to be more effective and suitable for use as a bio‐preservative in seafood.

Effect of Bile on Campylobacter species isolated from stool samples in Osogbo

Background: Campylobacter jejuni is a prevalent human pathogen and a major cause of bacterial gastroenteritis worldwide. In humans, C. jejuni colonises the intestinal tract, and its tolerance to bile is crucial for bacteria to survive and establish infection. Campylobacter jejuni and C. coli have the highest rate of foodborne-related clinical Campylobacteriosis. The study aims to determine the effect of bile salts, acid, and bacteriocin on campylobacter isolates obtained from stool samples. Methods: Campylobacters were identified phenotypically in this study using biochemical tests and genotypically using 16S rRNA species-specific gene amplification by PCR. The confirmed twenty-five Campylobacter isolates comprising18 C. jejuni and 7 C. coli were tested for physiological factors such as bile tolerance, bacteriocin tolerance and ability to synthesise proteolytic enzymes on a solid medium. Results: Campylobacter isolates survived at different concentrations of bile (2.1 -6.8%), low pH (7.1- 3.2) and in the presence of bacteriocin (3.8-6.8 AU/mL) with the production of proteolytic enzymes in the range of 16.2-15.2 mm. Conclusion: The ability of Campylobacter spp to survive in the presence of bacteriocin and different concentrations of acid and bile salt indicates the strains’ virulence

Characterization and Control of Antibiotic-Resistant Camalti Saltern's Isolates with Bacteriocins

Camalti Saltern is the largest solar saltern in Izmir, Turkey. The salt obtained from Camalti Saltern is used in food and leather industries to prevent bacterial growth. In this saltern, seawater is pumped into shallow ponds. Then, the sun and wind cause evaporation and crystallization, finally sea salt is produced. Due to the fact that Camalti Saltern contains various halophilic bacteria, the goals of the present study were to isolate and identify haloversatile bacteria from Camalti Saltern’s brine samples, to examine their antibiotic resistance profiles, to determine antimicrobial activities under optimum environmental conditions, to determine bacteriocin concentration by Bradford Method, to detect Minimum Inhibitory Concentrations (MIC) and Minimum Bactericidal Concentrations (MBC) of bacteriocins against multidrug-resistant isolates, and to observe the cell structure of bacteriocin-treated bacteria under SEM. Sixteen bacterial isolates were recovered from Camalti Saltern’s brine samples and were identified as 14 different species (Bacillus haynesii, Bacillus simplex, Bacillus subtilis subsp. stercoris, Bacillus pumilus,Staphylococcus petrasii subsp. jettensis, Staphylococcus saprophyticus subsp. saprophyticus, Kocuria sediminis, Rhodococcus enclensis, Marinobacter hydrocarbonoclasticus, Vibrio olivae, Marinomonas communis, Pseudomonas psychrotolerans, Salinivibrio costicola subsp. vallismortis, Vibrio neocaledonicus). Percentages of antibiotic resistance of isolates were 63% to aztreonam, 50% to amoxicillin/clavulanic acid, 44% to ampicillin, 44% to cefadroxil, 31% to imipenem, 19% to ampicillin/sulbactam, 6% to chloramphenicol, 6% to tetracycline, 6% to mupirocin, 6% to meropenem. The bacteriocin concentrations of Rhodococcus enclensis and Salinivibrio costicola subsp. vallismortis were measured as 1.02 mg/mL and 1.25 mg/mL, respectively. Bacteriocins of Rhodococcus enclensis and Salinivibrio costicola subsp. vallismortis, which were not resistant to any antibiotics tested,exhibited the inhibitory effect against Kocuria sediminis resistant to ten antibiotics and Bacillus pumilus resistant to four antibiotics. Bacteriocin of Salinivibrio costicola subsp. vallismortis also demonstrated the inhibitory effect against Pseudomonas psychrotolerans resistant to five antibiotics. Scanning electron micrographs showed that cell morphologies of bacteriocin-treated isolates (Kocuria sediminis, Bacillus pumilus, Pseudomonas psychrotolerans) were damaged. In conclusion, bacteriocins produced from the haloversatile Camalti saltern isolates may be used in the leather industry to prevent the growth of antibiotic-resistant haloversatile bacteria.

Characteristics Salivaricins producing Streptococcus salivarius isolated from gingiva

The bacteriocins study (Salivaricins) produced by Streptococcus salivarius. S. salivarius strains were isolated from healthy gingiva , The bacteriocin production under anaerobic conditions at 37°C for 24 hrs and inoculum (1.5 ˟ 109 CFU/ml) and Salivaricins was purified by precipitation ammonium sulphate, (75)% chromatofocusing by using column Sephadex G-50 the antibacterial activity against streptococci oral and other bacterial oral species was detection positive and ngative strain showed a different activity. The molecular weight of Salivaricins to be 8 kDa. The cells viability was decreased with increasing the concentration of Bacteriocin and the IC50 values of the HdFn cells (2.5 µg/mL).In conclusion, S. salivarius bacteriocin could be a good antibacteral agent and acivity against other types of species isolation gingiva.

Modeling the effects of pH variation and bacteriocin synthesis on bacterial growth

Bacteriocin secretion and the modification of extracellular pH are some competitive adaptations that bacteria have acquired to persist against adverse environmental conditions. Thus, its permanence in a microbial network is determined by the adaptation that the bacterium has, therefore, directly affecting the rate of bacterial growth and its population balance. In this regard, it should be noted that bacterial secretion plays an important role in bacterial control, both intra and inter-specific, by modifying the amount of bacteria in equilibrium, while the pH determines the maximum rate of bacterial growth and the effectiveness and degradation of bacteriocins release. From the point of view of mathematical modeling, these attributes favor extending the logistic growth model as a base system for bacterial growth by incorporating a bacteriocin-bacteria association term. On the other hand, bacteriocin secretion and pH variation are based on the Luedeking-Piret function, where pH levels influence each mathematical term of bacterial growth and bacteriocin concentration. Taking all of this into account, the ordinary differential equation model emerges, which, through Lyapunov’s theory, demonstrates the stability and absence of chaos in the proposed model, while the simulations confirm it. The modeling proposed in this work has the capacity to replicate diverse scenarios of great interest, such as microbial contamination in medical supplies and the food industry.

Isolation and Molecular Identification Of Lactobacillus Bacteria and Evaluation of Their Efficacy In Inhibiting The Pathogenic Fungus Pythium aphanidermatum

Twenty-eight isolates of Lactobacillus were isolated from the rhizosphere of pea cultivated in the fields of five districts in Salah al-Din, which included: Tikrit, Al-Alam, Al-Sharqat, Samarra and Al-Baiji. The isolates identified according to molecular diagnosis using the analysis of the 16S rRNA sequences and were divided into five species: 7 Isolates of L. fermentum, 3 isolates of L. casei, 9 isolates of L. plantarum, 4 isolates of L. herbarum and 5 isolates of L. paralimentarius. Antagonism tests were conducted for these isolates against the pathogen Pythium aphanidermatum, the highest rate of inhibition was by isolates of bacteria L. paralimentarius 1981 reached 2.7 mm, followed by isolate L.plantarum 1982 with an inhibition rate of 2.5 mm. In the antagonism test using bacterial filtrate of L. paralimentarius 1981, the concentration of 30% was the highest in inhibiting the pathogenic fungus, as the fungus colony diameter reached 3.22 cm, followed by the concentration of 20 and 25%, as the colony diameter reached 4.47 and 3.68 cm, respectively. L. paralimentarius 1081 was recorded in the databases of the World Genetic Bank within the accession number MW149434.1. This is the first record of this bacteria in Iraq. L. paralimentarius 1081 showed the highest production of the antibacterial active substances including siderophores, total phenols and bacteriocin reached to 61.24%, 1.05 mg/ml and 18.02 mg/ml, respectively, as well as pH decreased to 4.5. The results also showed there are a strong correlation of pathogenic fungus inhibition with high concentrations of siderophores, total phenols, bacteriocin and low pH in the bacterial filtrate.

Transcriptomic analysis of bacteriocin synthesis and stress response in Lactobacillus paracasei HD1.7 under acetic acid stress

Bacteriocins from lactic acid bacteria are natural preservatives that inhibit foodborne pathogenic microorganisms and have recently attracted much attention. Acetic acid metabolism is part of the core of central metabolism. To elucidate the acetic acid stress response of L. paracasei HD1.7, we performed high-throughput RNA-seq to compare gene expression under different concentrations of acetic acid stress. The results showed that with increasing acetic acid stress, the concentration of bacteriocin was increased, its production rate was accelerated, and the number of differentially expressed genes also increased. The continuously upregulated and downregulated KEGG pathways adjusted to the increase in acetic acid stress. The late-stage regulatory system of bacteriocin synthesis was related to ABC transporters (OppABCDF system). Purine and pyrimidine metabolism may provide ATP for ABC transporters. Acetic acid stress reduced glutamate biosynthesis, but arginine biosynthesis increased to attenuate acid stress. In addition, the KEGG enrichment analysis results of different environmental stresses (acetic acid, HCl, citric acid and ethanol stress) indicated that ABC transporters and fatty acid metabolism were the keys to bacteria adapting to environmental stress. This experiment lays the foundation for further research on bacteriocins.

The Effect of Bacteriocin Isolated From Lactobacillus rhamnosus on Pseudomonas aeruginosa Lipopolysaccharides

Background: Bacteriocins are heterogeneous inhibitory substances that could affect the bacteria belonging to the same genus. Both gram-positive and gram-negative bacteria produce bacteriocins. One of the best sources of producing bacteriocins is Lactobacillus. The aim of this study was to isolate and purify bacteriocin from Lactobacillus rhamnosus and assess its effects on Pseudomonas aeruginosa and synthesis of its lipopolysaccharide. Methods: L. rhamnosus was prepared and cultured at MRS broth and incubated at 37ºC for 24 hours. Then, the medium was centrifuged for the isolation of bacteriocin and the supernatant was considered as bacteriocin. Antibacterial properties of different concentrations of bacteriocin (50, 100, 200, and 400 μg/mL) against P. aeruginosa were assayed by using agar diffusion and broth micro dilution methods. Also, the effect of bacteriocin against lipopolysaccharide synthesis in P. aeruginosa was analyzed by using one unit of minimum inhibitory concentration (MIC) for bacteriocin. Results: The results showed that all bacteriocin concentrations had antibacterial activity against P. aeruginosa. The MIC value was 31.25 μg/mL and minimal bactericidal concentration (MBC) was 62.5 μg/mL. Also, the synthesis of lipopolysaccharide decreased during P. aeruginosa growth period, and it reached zero after 5 hours. Conclusions: The results of this study showed the antibacterial effect of bacteriocin isolated from L. rhamnosus against P. aeruginosa. In addition, this bacteriocin prevented the lipopolysaccharide synthesis in P. aeruginosa.

Purification and antimicrobial mechanism of a novel bacteriocin produced by Lactobacillus rhamnosus 1.0320

For a long time, the abuse of antibiotics and the excessive use of synthetic preservatives have caused harm to human health. Bacteriocins produced by lactic acid bacteria (LAB) are nontoxic and exhibit potential as natural preservatives. In this experiment, the bacteriocin 1.0320 produced by Lactobacillus rhamnosus 1.0320 screened from traditional koumiss was used as the research object. The main purpose of the experiment was to purify bacteriocin 1.0320 and study its antimicrobial mechanism. Bacteriocin 1.0320 exhibited antimicrobial activity against gram-positive and gram-negative bacteria. Bacteriocin 1.0320 in cell-free fermentation supernatant (CFS) was purified by ethyl acetate extraction and anion exchange chromatography. The molecular mass of bacteriocin 1.0320 was 1–3.3 KDa as assessed by dialysis and Tricine sodium dodecyl sulphate-polyacrylamide gel electrophoresis (Tricine-SDS-PAGE). The minimum inhibitory concentration of bacteriocin 1.0320 on Escherichiacoli UB1005 was 0.072 mg/mL. Bacteriocin 1.0320 can form pores on the surface of cell membrane, increase the permeability of cell membrane, dissipate the cytoplasmic membrane potential and transmembrane pH gradient, and destroy the integrity of cell membrane, causing cell content to flow out and cell death. The effect is related to the concentration of bacteriocin 1.0320. This information provides the theoretical basis for the antimicrobial mechanism of L. rhamnosus bacteriocin.

Physical and microbiological properties of sausage with addition of crude bacteriocin supernatant Lactobacillus fermentum L23 in cold storage

The purpose of this study was to determine the physical and microbiological properties of sausages with the addition of crude bacteriocin supernatant Lactobacillus fermentum L23 stored at cold temperatures. Research used a completely randomized design (CRD) 4x3 factorial pattern with 2 replications as a group. Factor A was application of bacteriocin concentration which consists of 4 levels, namely A1: 0%, A2: 3%, A3: 6%, A4: 9%. Factor B was the storage time at cold temperatures, namely B1: 0 days, B2: 6 days, B3: 12 days. The results showed that there was a significant interaction (P<0.05) on differences in the addition of bacteriocin supernatant concentration and storage time in cold temperatures, against total aerobic bacterial colonies, but there was no interaction (P>0.05) on moisture content and the pH value of sausages. Factor A can have a significant effect on the pH of the sausage, while factor B can have a significant effect on the moisture content of sausage. The conclusion of this study is that the best bacteriocin supernatant concentration for sausages is 6% and storage time in cold temperatures for 6 days with 62.52% moisture content, pH 5.75 and total plate count 4 x 103 CFU/g.

Growth promoting activity of Penaeus indicus by secondary metabolite producing probiotic bacterium Bacillus subtilis isolated from the shrimp gut

In this study, 104 bacteria were isolated from the gut of Penaeus indicus. The morphologically different bacterial isolates were screened for probiotic properties. The strain D5 showed potent activity against various bacteria. The isolated strain Bacillus subtilis showed 17 mm zone of inhibition against Bacillus sp., 19 mm against Pseudomonas sp., 22 mm against Vibrio sp., and 22 mm against Micrococcus sp. The bacterial growth and bacterocin production in relation with incubation time was evaluated. Bacteriocin production was found to be high at the stationary phase and reduced considerably after fifth day. Bacterial growth and bacterocin production was maximum at pH 7.0 and optimum between pH 6.0 and 8.0. Incubation temperature is one of the important factors which significantly influences on the growth and production of bacteriocin. Bacterial growth and bacterocin production (17 ± 2 mm) were maximum at 30 °C. Glucose stimulated growth and bacterocin production (21 ± 3 mm). Among the supplemented nitrogen sources, glycine positively influenced on growth and metabolite production. In this study, bacteriocin supplemented diet enhanced the growth than control shrimp Bacteriocin was administered at various doses ranged between 10 and 50 mg/100 gm level. Shrimp length was 3.3 ± 0.13 cm and shrimp weight was 9.7 ± 0.12 g in 100 mg. The present finding revealed enhanced growth at high bacteriocin concentration. At 2 × 102 CFU/100 g probiotics in feed, the juvenile shrimp attained 16.8 ± 0.11 g after 40 days. The weight gain was 16.8 ± 0.11 CFU/100 g at 10 × 102 CFU/100 g probiotic concentration.

Nisin reduces the Staphylococcus aureus count without changing the characteristics of artisanal Minas cheese from Araxá

O queijo tradicional de Araxá é produzido com leite cru, o que representa um risco para a saúde dos consumidores. A ação da nisina (100 UI/g e 400 UI/g) contra Staphylococcus aureus durante a maturação de Queijos Minas Artesanais de Araxá foi avaliada e a nisina reduziu a contagem de S. aureus para menos de 1 log UFC/g do começo ao fim da maturação. A nisina aumentou ligeiramente o pH e o teor de umidade e diminuiu o teor de gordura do Queijo Minas Artesanal de Araxá; no entanto, com a menor concentração de bacteriocina, essas mudanças não alteraram os índices de maturação, cor ou textura do queijo, que variaram apenas em função da maturação. A nisina tem o potencial de limitar o crescimento de S. aureus em Queijo Minas Artesanal de Araxá, sem alterar as características essenciais deste produto artesanal.

Migration of Bacteriocins Across Gastrointestinal Epithelial and Vascular Endothelial Cells, as Determined Using In Vitro Simulations

Little is known about the migration of bacteriocins across human cells. In this study, we report on migration of three bacteriocins nisin, plantaricin 423 and bacST4SA across colonic adenocarcinoma (Caco-2) cells and human umbilical vein endothelial cells (HUVECs). Bacteriocins were fluorescently labelled while still maintaining antimicrobial activity. Migration of fluorescently labelled bacteriocins across monolayers was assessed in vitro using transmigration well inserts. After 3 h, 75% of nisin, 85% of plantaricin 423 and 82% of bacST4SA migrated across the Caco-2 cell monolayer. Over the same time span, 88% nisin, 93% plantaricin 423 and 91% bacST4SA migrated across the HUVEC monolayer. The viability of both cell types remained unchanged when exposed to 50 µM of nisin, plantaricin 423 or bacST4SA. The effect of human plasma on bacteriocin activity was also assessed. Activity loss was dependent on bacteriocin type and concentration, with the class-IIa bacteriocins retaining more activity compared to nisin. This is the first report of bacteriocins migrating across simulated gastrointestinal- and vascular-barriers. This study provides some of the first evidence that bacteriocins are capable of crossing the gut-blood-barrier. However, in vivo studies need to be performed to confirm these findings and expand on the role of bacteriocin migration across cell barriers.