Bile Salt Tolerance Research Articles

Extending Viability of Bifidobacterium longum in Chitosan-Coated Alginate Microcapsules Using Emulsification and Internal Gelation Encapsulation Technology.

Bifidobacteria are considered one of the most important intestinal probiotics because of their significant health impact. However, this ability is usually limited by gastrointestinal fluid and temperature sensitivity. Emulsification and internal gelation is an encapsulation technique with great potential for probiotic protection during storage and the gastrointestinal transit process. This study prepared microcapsules using an emulsification and internal gelation encapsulation method with sodium alginate, chitosan, and Bifidobacterium longum as wall material, coating material, and experimental strain, respectively. Optical, scanning electron, and focal microscopes were used to observe the microcapsule surface morphology and internal viable cell distribution, and a laser particle size analyzer and zeta potentiometer were used to evaluate the chitosan-coating characteristics. In addition, microcapsule probiotic viability after storage, heat treatment, and simulated gastrointestinal fluid treatment were examined. Alginate microcapsules and chitosan-coated alginate microcapsules both had balling properties and uniform bacterial distribution. The latter kept its balling properties after freeze-drying, verified by scanning electronic microscopy (SEM), and had a clear external coating, observed by an optical microscope. The particle size of chitosan-coated alginate microcapsules was slightly larger than the uncoated microcapsules. The zeta potential of alginate and chitosan-coated alginate microcapsules was negative and positive, respectively. Heat, acid and bile salt tolerance, and stability tests revealed that the decrease of viable cells in the chitosan-coated alginate microcapsule group was significantly lower than that in uncoated microcapsules. These experimental results indicate that the chitosan-coated alginate microcapsules protect B. longum from gastrointestinal fluid and high-temperature conditions.

Genomic Comparison of Lactobacillus helveticus Strains Highlights Probiotic Potential.

Lactobacillus helveticus belongs to the large group of lactic acid bacteria (LAB), which are the major players in the fermentation of a wide range of foods. LAB are also present in the human gut, which has often been exploited as a reservoir of potential novel probiotic strains, but several parameters need to be assessed before establishing their safety and potential use for human consumption. In the present study, six L. helveticus strains isolated from natural whey cultures were analyzed for their phenotype and genotype in exopolysaccharide (EPS) production, low pH and bile salt tolerance, bile salt hydrolase (BSH) activity, and antibiotic resistance profile. In addition, a comparative genomic investigation was performed between the six newly sequenced strains and the 51 publicly available genomes of L. helveticus to define the pangenome structure. The results indicate that the newly sequenced strain UC1267 and the deposited strain DSM 20075 can be considered good candidates for gut-adapted strains due to their ability to survive in the presence of 0.2% glycocholic acid (GCA) and 1% taurocholic and taurodeoxycholic acid (TDCA). Moreover, these strains had the highest bile salt deconjugation activity among the tested L. helveticus strains. Considering the safety profile, none of these strains presented antibiotic resistance phenotypically and/or at the genome level. The pangenome analysis revealed genes specific to the new isolates, such as enzymes related to folate biosynthesis in strains UC1266 and UC1267 and an integrated phage in strain UC1035. Finally, the presence of maltose-degrading enzymes and multiple copies of 6-phospho-β-glucosidase genes in our strains indicates the capability to metabolize sugars other than lactose, which is related solely to dairy niches.

Investigating the probiotic characteristics of four microbial strains with potential application in feed industry.

The present study aimed to evaluate the probiotic characteristics of certain microbial strains for potential use as feed additives. Three bacterial strains and a yeast previously isolated from different environments were investigated. The strains were subjected to molecular identification and established as Lactobacillus paracasei CP133, Lactobacillus plantarum CP134, Bacillus subtilis CP350 and Saccharomyces cerevisiae CP605. Lactobacillus sp. CP133 and CP134 exhibited antibiosis, antibiotic activity, and relative odor reduction ability. Bacillus subtilis CP350 was thermotolerant, reduced hydrogen sulfide gas and showed significant proteolytic activity, whereas Saccharomyces cerevisiae CP605 exhibited high acid and bile salt tolerance. In general, the isolates in this study demonstrated improved functional characteristics, particularly acid and bile tolerance and relative cell adhesion to HT-29 monolayer cell line. Results in this work provides multifunctional probiotic characteristics of the strains for potential development of probiotics and cleaning of the environment.

Evaluation of Probiotic Potential of Lactic Acid Bacteria Isolated from Raphia Palm Wine (Raffia mambillensis)

Aim: The present study was undertaken to assess the probiotic potential of lactic acid bacteria strains isolated from raphia palm wine (Raffia mambillensis O.) of the South West region of Cameroon.
 Study Design: The study site and sample were randomly chosen and the responses assessed were submitted to analyses of variance.
 Place and Duration of Study: The study was carried out in Ekona in the South West region of Cameroon, between February 2017 and October 2018.
 Methodology: Physicochemical analyses were performed to characterize the Raphia palm wine samples. Lactic acid bacteria were isolated from these samples using pour plate method, and the isolates were tested for their antimicrobial activity, low pH and bile salts tolerance, antibiotic sensitivity, hemolytic activity and enzymes production. The active isolates were identified phenotypically using API 50 CHL.
 Results: The results revealed that among the nine isolates, only three were active against Escherichia coli BL21, Escherichia coli, Salmonella typhi, Salmonella enterica and Staphylococcus aureus with inhibition diameters ranging from 10 to 25 mm. The three isolates which exhibited antimicrobial activity were able to survive at simulated stomach pH (pH 3.0) with survival rate above 80% and in the presence of bile salts at 1% with survival rates above 50%. All three isolates gave negative results for hemolytic activity and were resistant to most antibiotic treatments. These three isolates produced β-galactosidase, which is beneficial for lactose intolerance. They also produced some non-carcinogenic enzymes including leucine arylamidase, crystine arylamidase, acid phosphatase, α-galactosidase, α-glucosidase, β-glucosidase, and N-acetyl-β-glucosamidase. Identification of these three isolates with API kit 50 CHL reveals that they are Lactobacillus lactis, Lactobacillus plantarum and Lactobacillus brevis.
 Conclusion: Our findings revealed that raphia palm wine can be an excellent source of probiotic lactic acid bacteria.

Evaluation of potentially probiotic attributes of certain dairy yeast isolated from buffalo sweetened Karish cheese

Egyptian traditional cheese has a long history and still represent an important part of the Egyptian diet. A lot of scientific studies in probiotic topic is usually related to bacteria, in particular lactic acid bacteria, and there is lack of information about potentially probiotic yeasts, except Saccharomyces boulardii. In the current study, 50 samples of traditional Egyptian buffalo sweetened cheese randomly were collected from five local Egyptian markets for yeast isolation. Isolated yeast species were identified using API20 kits techniques and the most frequently isolates were genotypically confirmed identified using the variability in the ITS rDNA. Appropriate in vitro assays have been conducted to examine their probiotic potentiality counting acid and bile salts tolerance, stimulated gastrointestinal tract tolerance, cell adhesion/hydrophobic characteristics, killer toxin productivity and antimicrobial activity against some clinical and food borne pathogens. The incidence of the obtained yeast taxa was found to be; S. cerevisiae (25%), Wickerhamomyces anomalus (23%), Pichia kudriavzevii (19%), Kluyveromyces lactis (17%), Geotrichum candidum (6%), Debaryomyces hansenii (4%), Candida tropicalis (3%), Cryptococcus neoformans (1%), Rhodotorula glabrata (1%) and Trichosporon cutaneum (1%). The most frequently isolates (S. cerevisiae, W. anomalus and P. kudriavzevii) exhibited high tolerance to bile salts elevated concentrations up to 2.0 %. W. anomalus could withstand the elevated bile salts concentrations and it was the most tolerable yeast isolate to intestinal juice environment. W. anomalus showed the lowest eradication from intestinal mucosa as indicated by the hydrophobicity average percentage 11.891% to xylene comparing to the P. kudriavzevii which showed the highest hydrophobicity average percentage of 46.185% to chloroform. Yeast isolates S. cerevisiae, W. anomalus and P. kudriavzevii (particularly W. anomalus) were recognized as ideal potentially probiotic model having in vitro properties that make them favorable candidates for probiotic applications.

Antimicrobial Activity of Lactobacillus Species Against Carbapenem-Resistant Enterobacteriaceae.

ObjectiveThis study aims to identify suitable lactobacilli that have anti-carbapenem-resistant Enterobacteriaceae (CRE) activity with in vitro tolerance to pepsin and bile salts.MethodsFifty-seven Lactobacillus spp. strains encompassing nine species were collected for investigation. Their viabilities in the presence of pepsin and bile salts were tested using tolerance tests. Their anti-CRE effects were assessed by agar well diffusion and broth microdilution assay, as well as time-kill test.ResultsOf the 57 Lactobacillus isolates collected, 31 had a less than 2-log reduction in their viability in both pepsin and bile salt tolerance tests. Of these 31 isolates, 5 (LUC0180, LUC0219, LYC0289, LYC0413, and LYC1031) displayed the greatest anti-CRE activity with a CRE zone of inhibition greater than 15 mm in agar well diffusion assays. The minimal inhibitory percentages of supernatants from these five strains against CREs ranged from 10 to 30%. With the exception of LUC0180, which had a minimal bactericidal percentage ≥ 40%, the bactericidal percentage of all the strains ranged from 20 to 40%. The inhibitory effect of the cell-free culture supernatants from these Lactobacillus strains did not change after heating but was abolished as the pH changed to 7.0. After a 24-h incubation, five of the Lactobacillus strains at a concentration of 108 CFU/ml totally inhibited the growth of carbapenem-resistant Escherichia coli (CRE316) and Klebsiella pneumoniae (CRE632). After a 48-h incubation, the growth of CRE316 was completely inhibited under each concentration of lactobacilli based on time-kill test. Furthermore, when the concentration of lactobacilli was at 108 CFU/ml, the decline in pH was faster than at other concentrations.ConclusionSome Lactobacillus strains exhibit anti-CRE activity, which suggests potential applications for controlling or preventing CRE colonization or infection.

Functional probiotic attributes and gene encoding plantaracin among variant Lactobacillus Plantarum strains

Fourteen Lactobacillus plantarum strains isolated from various food sources and two different climatic regions, Ireland and Pakistan were analyzed for their probiotic functions. RecA gene based multiplex PCR amplifications and pulsed-field gel electrophoresis (PFGE) were performed to genetically characterize these strains at subspecies level. All the strains were tested for bacteriocin activity against major food borne pathogens (L. innocua and L. monocytogenes). Bacteriocin was further purified using HPLC and identified with MALDI TOF MS analysis. Identification of gene encoding plantaracin 423 along with its enzyme sensitivity assays to protinease K and pepsin were also performed. Probiotic properties of bacteriocin producing strains were also analyzed by acid tolerance, bile salt tolerance, survival in simulated gastric juice and antibiotic resistance tests. Ten distinctly different strains of PFGE patterns were identified following ApaI digestion. Antimicrobial screening showed five L. plantarum strains as the potential producers of bacteriocin, expressing GIZ (Growth inhibition zone) up to 12, 12, 14, 11 and 13 mm, respectively against L. innocua. Molecular characterization of these strains further exhibited that plantaracin gene was present in the genome of L. plantarum strains AS-4, AS-6, AS-7, AS-13 and AS-14. All strains presented significant in vitro functional probiotic potential. Current study therefore, not only highlights bacteriocin regulated probiotic potential of L. plantarum strains isolated from different sources and climatic regions but also designates high heterogeneity in functional properties of the L. plantarum strains.

Streptococcus macedonicus strains isolated from traditional fermented milks: resistance to gastrointestinal environment and adhesion ability.

In this study, Streptococcus macedonicus (S. macedonicus) strains were identified from Algerian traditional fermented milks (Lben and Rayeb). Important prerequisites of probiotic interest such as acidity, bile salts tolerance, and adhesion ability to epithelial cells were investigated. A combination of phenotypic (ability to grow on Bile Esculin Azide medium, BEA; on high salt content medium NaCl 6.5%; on alkaline medium pH9.6) and genotypic approaches (16S rRNA, ITS genes sequencing and MLST technique) allowed to identify four genetically distinct strains of S. macedonicus. These four strains and two references, Streptococcus thermophilus LMD-9 and Lactobacillus rhamnosus GG (LGG), were tested for their capacity to survive at low pH values, and at different concentrations of an equimolar bile salts mixture (BSM). Two different cell lines, Caco-2 TC7 and HT29-MTX, were used for the adhesion study. The results show that S. macedonicus strains selected constitute a distinct genetic entity from the Greek strain S. macedonicus ACA-DC-198. They were able to survive up to pH3 and could tolerate high concentrations of bile salts (10mM), unlike LMD-9 and LGG strains. Our strains also display in vitro adhesion similar to the LGG strain on Caco-2 TC7 and higher adhesion than the LMD-9 strain to Caco-2 TC7 and HT29-MTX cell models. This first characterization allows considering S. macedonicus as a potential candidate for possible probiotic effects that need to be investigated.

Phân lập, sàng lọc và khảo sát hoạt tính sinh học của vi khuẩn keo tụ sinh học trong ao nuôi tôm thẻ chân trắng tại tỉnh Trà Vinh

Aquaculture industry has been developing in Vietnam, however, the water pollution in ponds caused many difficult problems for aquaculture, especially shrimp farming. The use of microbial products to stabilize water quality, reduce the amount of suspended organic matter in the water and reduce the toxic gas in water is essential and bacterial strains with bio-flocculant activity are as solution. From 13 water samples collected from shrimp ponds at Tra Vinh province, 59 isolates were isolated including 39 isolates of Gram positive bacteria and 18 isolates of Gram negative bacteria. After screening these bacteria by Gram staining and spore staining methods, 22 isolates that were Gram positive and spore bacteria were identified. The flocculating rate of 22 Gram positive isolates with kaolin suspension showed that MS 9.4 had the strongest flocculating rate (75,83%). MS 9.4 isolate was identified by the 16S-rRNA sequencing and biological test. Some biological activities including salinity tolerance, acid tolerance, bile salt tolerance were identified. The biochemical characteristics of MS 9.4 were similar to Bacillus subtilis, while 16S-rRNA gene sequence of MS 9.4 strain was 100% similar to Bacillus subtilis IAM12118, so MS 9.4 was identified as Bacillus subtilis. This strain is resistant to salt (7%), tolerate with low pH (pH = 2), bile salt tolerant (2%) but it did not inhibit Vibrio spp.

인체 및 다양한 발효식품 유래 유산균의 충치유발 세균에 대한 항균활성 및 프로바이오틱스 기능성 연구

The occurrence of dental caries is mainly associated with oral pathogens, especially cariogenic Streptococcus mutans and Porphyromonas gingivalis. The objective of this study was to investigate antimicrobial activity against cariogenic associated pathogens, acid tolerance, bile salt tolerance, and autoaggregation of 12 presumptive Lactobacillus spp. isolated from human and fermented foods. Five strains were selected after qualitatively identifying high levels of antimicrobial activity against bacteria including S. mutans. Results show that selected strains survivability was tested in bile salt and acidic conditions to show their potential use as probiotics in the gastrointestinal tract. Indirect adhesion activity of selected strains measured by autoaggregation assay showed more than 60% autoaggregation after 5 h standing. Further studies are underway to demonstrate that the selected strains can be applied as potential probiotics for recovering oral ecosystem.

Probiotic properties of lactic acid bacteria isolated from faeces of Pongo abelli and Macaca fascicularis

Sumatran Orangutan (Pongo abelii) and Long-tailed Macaque (Macaca fascicularis) population are both facing a decline in the wild. Despite of the well-known cause of decline, which is habitat degradation, several issues like disease and infection are common in ex-situ conservation site. The study aimed to evaluate antimicrobial properties of lactic acid bacteria (LAB) isolated from faeces of Pongo abelli and Macaca fascicularis, as potential antagonist against common gut pathogens based on in vitro study. Following parameters were examined such as: antagonistic activity against Salmonella typhii, Escherichia coli, and Shigella sp. using disk-diffusion method; acid and bile-salt tolerance using simulated gastrointestinal fluids (SIF) and co-aggregation ability. The study obtained ten isolates in which six of them exhibited antagonist properties namely isolate OU1, OU2, OU5, MEP1, MEP3 and MEP5. Two isolates, namely OU5 and MEP5 showed good results in terms of acid and bile-salt tolerance and co-aggregation ability. The results then may imply the promising use of potential LAB as probiotics in the future study.

Screening and safety evaluation of lactic acid bacteria with selenium adsorption capacity

Selenium, one of the essential trace elements in humans and animals, is involved in various biochemical and physiological functions, such as improving immunity and antioxidant properties. Lactic acid bacteria, recognized as generally recognized as safe (GRAS) in the world, have the ability to convert inorganic selenium into organic form and have plenty of outstanding probiotic properties, including regulation of gut microbiota, increase of antioxidant capacity, and decrease of intestinal inflammation and so on. Therefore, using them as a safe and efficient selenium supplementation carrier is increasingly becoming a hotspot in recent research. In order to obtain a strain of lactic acid bacteria with good selenium adsorption capacity, 43 strains of Lactobacillus of different species were screened by determining the adsorption rate of selenium in vitro . The adsorption conditions were as follows: The initial selenium concentration was 50 mg/L, the initial cell concentration was 1 g/L, and the adsorption time was 1 h. The selenium adsorption rate and selenium adsorption capacity of the strains were determined by measuring the selenium content of the dried bacteria after nitrolysis. The selenium levels were determinated by inductively coupled plasma mass spectrometer (ICP-MS). At the same time, the adsorption characteristics of the strain were studied by changing the initial pH, initial cell concentration, initial selenium concentration and adsorption time, and acid and bile salt tolerance were determined to confirm whether it can still maintain high activity in the gastrointestinal tract. Then the safety of the strain was evaluate by the acute toxicity test and the 30-d feeding experiment, as well as antibiotic resistance of the strain. The results showed that the Lactobacillus plantarum RS7-1 had the most excellent selenium adsorption ability among the 43 strains, and its adsorption rate for selenium was up to 40.79%±1.27%. The optimum pH of the strain was 5.0, and the optimal initial bacterial concentration was 2 g/L. The maximum adsorption capacity was reached when the initial selenium concentration was 20 mg/L. The adsorption of selenium can be divided into two stages, rapid adsorption stage and adsorption equilibrium stage. The equilibrium time was reached when the adsorption time was 60 min. At the same time, the strain has outstanding acid and bile salt tolerance, without species-specific antibiotic tolerance, and after safety evaluation, the mice fed with the strain shows no significant difference in the food consumption, body weight, biochemical index, hematological indexes of blood compared with mice in blank group, and no organ and tissue lesions were detected. In conclusion, Lactobacillus plantarum RS7-1 is a strain of lactic acid bacteria with superb selenium adsorption capacity, great acid and bile salt tolerance, without toxicity and side effect. This study provides an idea for the selenium supplement with probiotics as the carrier, and the selenium adsorption capacity can be further improved by optimization of adsorption conditions, mutation breeding and genetic engineering, thereby increasing the application value of selenium-enriched probiotic products in the future.

Probiotic effects of <italic>Lactobacillus casei</italic> Zhang: From single strain omics to metagenomics

Lactobacillus casei Zhang (LCZ) is a well-studied probiotic bacterium that was inspired by traditional Mongolian medicine and isolated from naturally fermented koumiss in Inner Mongolia. There are three major stages of LCZ research and development. It contains single strain omics and in vitro evaluation stage (Stage 1), gut dominated microbes and in vivo evaluation stage (Stage 2) as well as metagenomics and clinical evaluation stage (Stage 3). LCZ was screened out from acid resistance, bile salt tolerance and processed favorable effects of in vitro cell adhesion characteristics and regulation of macrophage activity. And then, the whole genome of LCZ was determined and analyzed, which is the first identified Lactobacillus genome in China at 2008. Antibiotics resistance experiments showed a strong stability of LCZ genome under amoxicillin or gentamycin exposure through 2000 generations of laboratory evolution. A set of functional proteins such as NagA and NagB were identified from LCZ proteomics of growth process, acid stress or bile salt tolerance. Furthermore in vivo tests, LCZ has been demonstrated to process several beneficial effects including regulating microbiota abundance and ratios, lipid peroxidation inhibition and increasing antioxidant enzymes activities, regulating cellular and humoral immunity and tumor associated immune function, hepatoprotective effect and inhibition of liver transplanted tumor growth. Researchers have long appreciated the benefits of the gut microbiota to health. Moreover, LCZ was confirmed to promote the intestinal Bacteroides abundance and thereby alleviating impaired glucose tolerance and preventing type 2 diabetes mellitus by Q-PCR methods. Using the third generation PacBio sequencing technology, LCZ could delay the colon cancer progression in mice via altered gut microbiota composition and microbial acetic acid production. Detailedly, Alloprevotella rava and Parabacteroides merdae are the precise potential health-promoting species increased by LCZ intake. In addition to modulate gut microbiota composition, probiotic LCZ also manipulate bile acids, affects its conversation and induced tissue influx of chloride ion, which can impact the expression of chloride ion related proteins (eg.CLCN3 and CFTR). Small-scale human trial indicated that LCZ could maintain the abundance of gut microbiota, increase the number of beneficial bacteria and reduce potential harmful bacteria via 454 pyrosequencing. In 2018, a large-scale, randomized, double-blind and placebo-controlled study was conducted by LCZ administration in Malaysian population. In adult subjects, it confirmed that LCZ could prevent upper respiratory tract infection including reducing the number of days for pharyngeal and general flu symptoms as well as nasal symptoms. In elderly populations, LCZ not only reduced nasal symptoms but also alleviated aged index including improving the mean corpuscular hemoglobin concentration and erythrocyte sedimentation rate. These are attributing to microbiota modulation and its mediated immunity such as increased anti-inflammatory IL-4. It is suggested that LCZ will exert more benefits in microbiota regulation and became a promising health food / special medical food for preventive or therapeutic effects.

Screening of lactic acid bacteria isolated from fermented Cornus officinalis fruits for probiotic potential

AbstractThe objective of this study was to screen probiotic lactic acid bacteria (LAB) with beneficial properties such as acid and bile salt tolerance, antibacterial activity, autoaggregation ability, and cholesterol‐lowering capacity from fermented Cornus officinalis fruits. Eleven probiotic LAB strains, identified as ten Lactobacillus plantarum and one Lactobacillus casei, were screened out and evaluated by in vitro tests. The results of principal component analysis (PCA) based on probiotic characteristics suggested that L. plantarum 2519, 3725, and 3735 were promising probiotic candidates, which were better than the probiotic reference strain, Lactobacillus rhamnosus GG. Among them, L. plantarum 2519 showed the hightest autoaggregation value of 94.62%, and L. plantarum 3725 showed a cholesterol assimilation percentage of 47.83% and remarkable antimicrobial activity against five foodborne pathogens with the cell number decrease from 3.68 to 4.60 log cfu/mL. These results indicate that these three LAB strains are good candidates as probiotic starters.Practical applicationsCornus officinalis is known as a kind of medicinal plant with fruits having many pharmacological activities, such as improving liver and kidney function, potent hpyerglycemic and antioxidant effect. C. officinalis is rich in endophytes, and its pharmacological activities may be associated with the metabolic products of endophytic bacteria. Therefore, the exploitation of microbial resources in spontaneous fermented C. officinalis fruits is beneficial to select probiotics. Moreover, the fruits from a natural reserve should be an excellent resource, attributing to the low impact of antimicrobial contamination may guarantee non or low intensity of antibiotic activity of their endophytic bacteria.

Probiotic properties of Bifidobacterium species isolated from mother’s milk and infant feces

Probiotics are live microorganisms that provide health benefits when consumed. Bifidobacteria are one of the major genera of bacteria that make up the colon flora in mammals and have great beneficial impact on health. This study was performed to culture and characterize some potential Bifidobacterium sp. isolated from mother's milk and infant feces. Eleven isolates were presumptively identified as Bifidobacteriums sp. based on morphological characteristic and biochemical properties such as catalase, oxidase, Esculin test, Gelatinase activities and production of gas from glucose. Probiotic potentials of the isolates were investigated through probiotic potentiality tests e.g. pH tolerance test, NaCl tolerance test, bile salt tolerance test, antimicrobial activity, growth rate in gastric juice, antimicrobial susceptibility (Antibiogram). Four of the isolates BI-3, BI-5, BI-9, and BI-14 were observed as potential probiotic based on their probiotic activities. These isolates showed resistance to stomach pH (pH 3.0), tolerance against 0.3% bile concentration and gastric juice tolerance. Most of the isolates were able to grow at 1- 6% NaCl concentration and the growth declined with the increase of the salt concentration. Proteolytic activity was measured to estimate the probable role of probiotics in protein digestion. For this purpose milk protein digestion was tested and these isolates had showed better proteolytic activity than others. Antimicrobial activity against pathogens showed better probiotic properties. These isolates were found to have moderately antibiotic susceptible to common antibiotics. This experiment revealed that these four isolates BI-3, BI-5, BI-9, and BI-14 have good probiotic properties and can be used as probiotics after successful molecular identification and completion of animal trial.
 Asian Australas. J. Biosci. Biotechnol. 2018, 3 (2), 122-135

In vitro selection of potential immunomodulatory multispecies lactic acid bacteria in broilers

Modulation of host immunity is one of the proposed benefits of the consumption of probiotics.In this study a total of 26 lactic acid bacteria belonging to eight different species were isolated from chicken gut. These twenty six probiotic organisms were characterized by Gram’s staining, biochemical methods using 21 sugars, pH tolerance and bile salt tolerance test. These probiotic organisms were identified using PCR amplification of 16S-23S spacer region and sequencing analysis. Based on the sequencing data, 6 different species were found to exist namely Enterococcus faecalis; Enterococcus faecium, Enterococcus hirae, Weissella cibaria, Lactobacillus salivarius, Pediococcus acidilactici. To select the immunomodulatory probiotic bacteria, the scoring index was established based on different chicken cytokine expression and B and T cell receptor expression studies. According to scoring index, Pediococcus acidilactici, Lactobacillus salivarius and Weissellacibaria showed highest levels of fold increase in the expression of Th1 cytokines viz. IL2, IL 12p40, IL1b and TNF a. Enterococcus faecalis and Enterococcus faecium showed highest levels of fold increase in the expression of Th2 cytokines viz. IL 4, IL10, TGF b and IL6.

The effects of inulin and fructo-oligosaccharide on the probiotic properties of Lactobacillus spp. isolated from human milk.

Abstract This study aims to determine the effects of inulin and fructo-oligosaccharide (FOS) on the probiotic properties of five Lactobacillus spp. isolated from human milk. Lactobacillus spp. were isolated and identified, and the growth characteristics, acid and bile salt tolerance, antagonistic effects, and cholesterol assimilation of Lactobacillus strains were investigated in the presence of inulin and FOS. Lactobacillus casei L1 was able to utilize inulin and FOS as carbon source as well as glucose even other strains were able to use, including Lactobacillus rhamnosus GG. This strain also showed high tolerance to acid and bile salt, even at pH 2.5 and 0.5% bile salt levels, respectively. Inulin and FOS promoted the antimicrobial activity of L. casei L1 against pathogenic bacteria. Cholesterol assimilation was higher than in the other and control probiotic strains in the presence inulin and FOS, which were measured as 14 and 25 mg/dL, respectively. In conclusion, L. casei L1 can use both inulin and FOS to maintain its viability both at digestive conditions and also the relevant prebiotics, and show broad antagonistic activity and cholesterol assimilation.

Lactobacillus plantarum YS-3 Prevents Activated Carbon-Induced Constipation in Mice.

The aim of this study was to determine the effects of Lactobacillus plantarum YS-3 (LP-YS3) on activated carbon-induced constipation in Kunming mice. The results of the experiment show that the antigastric acid activity and bile salt tolerance of LP-YS3 were stronger than those of Lactobacillus bulgaricus (LB). LP-YS3 inhibited loss of body weight caused by constipation and further reductions in fecal weight, particle number, and water content in mice. Moreover, LP-YS3 elevated the gastrointestinal transit rate and reduced the time required for initial black stool defecation. LP-YS3 also elevated motilin (MTL), endothelin (ET), acetylcholinesterase (AChE), substance P (SP), and VIP serum levels and reduced somatostatin (SS) levels in constipated mice. Hematoxylin-eosin (H&E) staining revealed that high concentration of LP-YS3 reduced the incidence of injuries to small intestine villi and the intestinal wall compared to carbon-induced constipation groups. Reverse transcription-polymerase chain reaction and western blot experiments demonstrated that LP-YS3 upregulated c-Kit, stem cell factor, and glial cell line-derived neurotrophic factor mRNA and protein expression and downregulated transient receptor potential vanilloid 1 and nitric oxide synthase expression in small intestine tissue from constipated mice. In conclusion, high concentrations of LP-YS3 had stronger and more beneficial effects than LB. Based on these results, we conclude that LP-YS3 can effectively inhibit constipation.

Antibacterial Activity of Lactic Acid Bacteria Isolated from Gastrointestinal Tract of “Ayam Kampung” Chicken Against Food Pathogens

Food borne disease results from ingestion of water and wide variety of food contaminated with pathogenic organisms. The main causes of food borne diseases are bacteria, such as Escherichia coli and Staphylococcus aureus. The objective of this study was to determine antimicrobial activity of lactic acid bacteria (LAB) isolated from local chicken gastrointestinal tract with an emphasis on their probiotic properties. The colonies of bacteria that producing clear zone on MRSA plus 0.5% CaCO3, Gram-positive and catalase-negative were isolated as lactic acid bacteria. Some of the strains (10 isolates) were tested for their ability to inhibit growth of Escherichia coli and Staphylococcus aureus, and for acid pH and bile salt tolerance. The results showed that the all selected isolates producing antimicrobial compounds inhibits the growth of Escherichia coli and Staphylococcus aureus, both in the supernatant and supernatant plus 2M NaOH, and still growing in medium condition with pH 2.0 and 0.1% bile salt. It revealing the potential use of the lactic acid bacteria from chicken gastrointestinal tract for probiotics in food.

Safety assessment and functional properties of four enterococci strains isolated from regional Argentinean cheese

The members of the Enterococcus genus are widely distributed in nature. Its strains have been extensively reported to be present in plant surfaces, soil, water and food. In an attempt to assess their potential application in food industry, four Enterococcus faecium group-strains recently isolated from Argentinean regional cheese products were evaluated using a combination of whole genome analyses and in vivo assays. In order to identify these microorganisms at species level, in silico analyses using their newly reported sequences were conducted. The average nucleotide identity (ANI), in silico DNA-DNA hybridization, and phylogenomic trees constructed using core genome data allowed IQ110, GM70 and GM75 strains to be classified as E. faecium while IQ23 strain was identified as E. durans. Besides their common origin, the strains showed differences in their genetic structure and mobile genetic element content. Furthermore, it was possible to determine the absence or presence of specific features related to growth in milk, cheese ripening, probiotic capability and gut adaptation including sugar, amino acid, and peptides utilization, flavor compound production, bile salt tolerance as well as biogenic amine production. Remarkably, all strains encoded for peptide permeases, maltose utilization, bile salt tolerance, diacetyl and tyramine production genes. On the other hand, some variability was observed regarding citrate and lactose utilization, esterase, and cell wall-associated proteinase. In addition, while strains were predicted to be non-human pathogens by the in silico inspection of pathogenicity and virulence factors, only the GM70 strain proved to be non-virulent in Galleria mellonella model. In conclusion, we propose that, in order to improve the rational selection of strains for industrial applications, a holistic approach involving a comparative genomic analysis of positive and negative features as well as in vivo evaluation of virulence behavior should be performed.