High Bile Concentrations Research Articles

Probiotic evaluation, adherence capability and safety assessment of Lactococcus lactis strain isolated from an important herb “Murraya koenigii”

Lactic acid bacteria (LAB) isolated from medicinal herb Murraya koenigii, commonly known as curry leaf, which promotes the growth and maintenance of gut microbiota, were studied for their probiotic potential. The key objective of this research was to isolate and evaluate probiotic characteristics, test adherence capabilities, and confirm their safety. Lactococcus lactis (MKL8), isolated from Murraya koenigii, was subjected to in vitro analysis to assess its resistance to the gastric environment, ability to adhere Caco-2 cells, anti-microbial activity, hydrophobicity, auto-aggregation, and safety profiling through MTT assay and hemolytic. MKL8 exhibited growth at 0.5% phenol concentrations (> 80%) and was able to survive in conditions with high bile concentrations (> 79%) and a relatively low pH (72%-91%). It shows high tolerance to high osmotic conditions (> 73%) and simulated gastric juice (> 72%). Additionally, MKL8 demonstrated strong hydrophobicity (85%), auto-aggregation (87.3%-91.7%), and adherence to Caco-2 cells. Moreover, it had an inhibitory effect against pathogens too. By performing the hemolytic and MTT assays, the non-toxicity of MKL8 isolate was examined, and it exhibited no harmful characteristics. Considering MKL8's resistance to gastrointestinal tract conditions, high surface hydrophobicity, non-toxicity, and ability to inhibit the tested pathogens, it can be concluded that MKL8 demonstrated promising probiotic properties and has potential for use in the food industry.

Recovery of Potential Starter Cultures and Probiotics from Fermented Sorghum (Ting) Slurries.

Fermented foods are thought to provide a source of probiotics that promote gut health. Consequently, isolation and characterization of fermented food strains and their applications in a controlled fermentation process or as probiotics present a new facet in this area of research. Therefore, the current study sought to identify dominant strains in sorghum-fermented foods (ting) and characterize their probiotic potential in vitro. Recovered isolates were identified as Lactobacillus helveticus, Lactobacillus amylolyticus, Lacticaseibacillus paracasei, Lacticaseibacillus paracasei subsp paracasei, Lactiplantibacillus plantarum, Levilactobacillus brevis, Loigolactobacillus coryniformis and Loigolactobacillus coryniformis subsp torquens based on the their 16S rRNA sequences. Increased biomass was noted in seven out of nine under a low pH of 3 and a high bile concentration of 2% in vitro. Bactericidal activities of isolated LABs presented varying degrees of resistance against selected pathogenic bacteria ranging between (1.57 to 41 mm), (10 to 41 mm), and (11.26 to 42 mm) for Salmonella typhimurium ATTC 14028, Staphylococcus aureus ATTC 6538 and Escherichia coli ATTC8739, respectively. Ampicillin, erythromycin, mupirocin, tetracycline and chloramphenicol were able to inhibit growth of all selected LABs. Thus, isolates recovered from ting partially satisfy the potential candidacy for probiotics by virtue of being more tolerant to acid and bile, antibacterial activity and antibiotic resistance.

Bile acid predicts congenital portosystemic venous shunt in patients with pulmonary arterial hypertension

The etiology of pulmonary arterial hypertension (PAH) is complex, especially the investigation of rare pathogeny is difficult. Congenital portosystemic venous shunt (CPSS) is a rare congenital anomaly in which the portal blood completely or partially bypasses the liver through a congenital portosystemic shunt, and drains directly into the inferior vena cava (IVC) (Howard and Davenport in J Pediatr Surg 32:494–497, 1997).CPSS is an uncommon cause of PAH (Christiane et al. in J Pediatr Gastroenterol Nutr 56:675–681, 2013), and often covered by other pathogenic factors. The clinical manifestations of CPSS-associated PAH are not specific, thus making it difficult to distinguish from PAH caused by other pathogenetic factors based on clinical presentations alone. This is a retrospective analysis of data from six patients with CPSS at a single center. Of these, five were diagnosed as PAH: four were also associated with other predisposing factors of pulmonary hypertension (PH). All patients had high serum bile concentration and high cardiac output. The aim of this retrospective study was to investigate the clinical recognition of PAH secondary to CPSS. The concentration of serum bile acid and cardiac output can be used as two important non-invasive indicators in clinical practice. Thus far, few studies have reported the clinical outcomes of CPSS-associated PAH specifically (Anna et al. in Hepatology 71:658–669, 2020;Franchi-Abella et al. in J Pediatr Gastroenterol Nutr 51:322–330, 2010;Uike et al. in Pediatr Pulmonol 53:505–511, 2018;). In the current study, such patients carried a poor prognosis if left untreated, or treated with pulmonary vasodilators alone.

PROBIOTIC CHARACTERIZATION OF SACCHAROMYCES CEREVISIAE Y196 AND Y197 ISOLATED FROM RICE CHHANG- A FERMENTED BEVERAGE OF LAHAUL SPITI

Fermented foods and beverages are rich source of probiotic microorganisms and yeasts are the most common microorganisms found in these fermented products. Fermented beverages are less explored for probiotics, therefore; the present study was focused on isolation, screening and characterization of probiotic yeast from rice Chhang, a fermented beverage of Lahaul Spiti. Ten yeast isolates were initially isolated from rice Chhang and out of which two isolates Saccharomyces cerevisiae Y196 and Saccharomyces cerevisiae Y197 were selected based on their antimicrobial activity. These two yeast isolates were examined for various probiotic properties such as survival at low pH, bile tolerance, microbial adhesion to hydrocarbons, cholesterol assimilation, exopolysaccharide production and haemolytic activity. Both isolates showed antimicrobial activity against all the tested pathogens used in this study, also showed high acid tolerance at pH 2 and pH 3 and can withstand high bile concentration as compared to control. Percentage of hydrophobicity was found to be 57 % and 41 % in Saccharomyces cerevisiae Y196 and Saccharomyces cerevisiae Y197, respectively. Both isolates were able to show high cholesterol assimilation with a maximum of 90 % in case of Saccharomyces cerevisiae Y197 with taurocholate. They were also found to be positive for exopolysaccharide production and showed no haemolytic activity. Hence, keeping in view the results of present study, these isolates can be proposed for preparation of various probiotic food products.

Identification of Lactobacillus strains from human mother milk and cottage cheese revealed potential probiotic properties with enzymatic activity

The main attempt of this study is to isolate, determine potential probiotic properties and enzyme production of some lactic acid bacteria (LAB). Among all isolates, two LAB strains isolated from human mother milk and cottage cheese revealed antimicrobial activity against some tested pathogenic strains. Both isolates inhibited all the tested pathogens except Escherichia coli. The two isolates were identified by morphological, biochemical properties and then by 16S rRNA gene sequencing technique as Lactobacillus acidophilus SAM1 and Lactiplantibacillus plantarum SAM2. Potential probiotic characters were investigated. Both strains survived in relatively low pH and high bile concentrations and were able to grow at 0.5% of pancreatin concentrations. Their growth decreased by increasing phenol from 0.2% till 0.5%. Both strains did not show hemolytic activity. Coaggregation potential was exhibited by the two strains against Staphylococcus aureus and Candida albicans. Hydrophobicity of Lactobacillus acidophilus SAM1 and Lactiplantibacillus plantarum SAM2, with ethyl acetate; were 88.1% and 82.8%, respectively. Lactobacillus acidophilus SAM1 was susceptible to Ampicillin, Penicillin, Erythromycin, Ciprofloxacin and Tetracycline; on the contrary, it resists Vancomycin and Cefoxitin; while Lactiplantibacillus plantarum SAM2 resists all tested antibiotics. Maximum growth was achieved using glucose as a carbon source and yeast extract as nitrogen source for both strains; however, glucose is the most preferred carbon source for microorganisms and it prevents the uptake of carbon from other sources like yeast by catabolite repression mechanism. Lactobacillus acidophilus SAM1 produces lipase enzyme, while Lactiplantibacillus plantarum SAM2 produces amylase and protease.

Risk Factors of Cholangiocarcinogenesis in Parasitization of a Natural Focal Ecopathogen Helminth <i>Opisthorchis felineus</i>

Epidemiological researches, carried out by professor A.A. Shain in Ob-Irtysh basin of Tyumen region, have allowed to consider chronic opisthorchiasis as facultative liver precancer and develop the original concept of cholangiocarcinogenesis on the background of long-term invasion by trematode Opisthorchis felineus of hepatobiliary system of the body. According to this concept, the initiating role in cholangiocyte transformation belongs to endogenous factors secondary bile acids, having mutagenic/carcinogenic properties, which formation is mediated by helminthosis-related exogenous intestinal microflora in intrahepatic bile ducts. Obtained data confirmed content of endogenous carcinogenic factors secondary bile acids in duct bile of chronic opistorchosis patients. Cholestasis, caused by long-term parasitization of helminth Opisthorchis felineus in hepatobiliary system of the body, mediates formation of the host promoter factors, contributing to cholangiocarcinoma progression. These include: high concentration in duct bile of bile acids, products of helminths activity and lipid peroxidation of somatic cell membranes. Promoter factors of cholangiocanerogenesis are also disorders of cholangiocyte membranes structure, tissue regulation of their regeneration, DNA repair and anti-tumorigenic protection of the body. The results of the study confirm the concept of occurrence and development of the process of cholangiocarcinogenesis in chronic opistorchosis infestation, proposed by Professor A.A. Shain and allow to reasonably develop approaches to the correction of homeostasis regulation systems of the organism in the specified helminthiasis. Which also determines the secondary prevention of malignant process in ductal epithelium of hepatobiliary system in posthelminthic period.

In vitro evaluation of probiotic potential and enzymatic profiling of Pichia kudriavzevii Y33 isolated from traditional home-made mango pickle

BackgroundFermented foods are the results of metabolic activities of various microorganisms. People have traditionally known how to culture desirable microorganisms, primarily lactic acid bacteria, yeasts, and filamentous molds, for the manufacture of edible foods. Yeast isolated from home-made mango pickle from Hamirpur, Himachal Pradesh, was assessed for probiotic properties and their enzymatic profiling. ResultsFour yeast isolates were isolated out of which P. kudriavzevii Y33 was selected on the basis of high acid tolerance as well as broadest antimicrobial activity. The selected isolate was observed to have high acid tolerance at pH 2 and show strong antimicrobial activity against all the pathogens examined. P. kudriavzevii Y33 can also withstand high bile concentration and showed high viability index, i.e., 95% at concentration of 2% of bile. The isolate was able to demonstrate high cholesterol assimilation in medium containing ox bile and taurocholate, at 88.58 and 86.83%, respectively. The autoaggregation ability of isolate increases with increasing the time of incubation and showed 87% of autoaggregation after 24 h of incubation. P. kudriavzevii Y33 exhibited resistance towards different antibiotics, found to be positive for exopolysaccharide production and showed no hemolytic activity. The isolate was observed to produce several enzymes such as β-galactosidase, protease, amylase, phytase, and lipase. ConclusionsThe results of the current study revealed that P. kudriavzevii Y33 has various beneficial qualities that suggest it could be used as probiotics. Enzymes produced by yeast isolate help in improving flavor and mineral availability in the fermented products.

Risk Factors for Bile Aspiration and its Impact on Clinical Outcomes.

INTRODUCTION:Bile reflux may cause for lung allograft rejection, yet there are no studies that determine (i) the relationship between gastric and lung bile concentrations, (ii) whether bile is present in lungs of nontransplant patients, (iii) the relationship between gastric dysmotility and lung bile, (iv) the impact of reflux therapies on lung bile, and (v) whether lung bile worsens outcomes in nontransplant patients. This study will address these gaps in the literature.METHODS:We prospectively recruited lung transplant (LTX) patients and nontransplant patients with respiratory symptoms (RP) and collected paired gastric and lung samples. Bile concentration and composition of samples was assessed using liquid chromatography–mass spectrometry. Bile results were compared with clinical parameters, including the presence of esophagitis, gastric dysmotility, and/or pathologic gastroesophageal reflux.RESULTS:Seventy patients (48 RP and 22 LTX) were recruited. Overall, 100% of gastric and 98% of bronchoalveolar lavage samples contained bile. The mean gastric bile concentrations in RP and LTX patients were 280 ± 703 nmol/L and 1,004 ± 1721 nmol/L, respectively (P = 0.02). There was no difference in lung bile concentrations between RP (9 ± 30 nmol/L) and LTX (11 ± 15 nmol/L, P = 0.7). Patients with delayed gastric emptying had higher lung bile concentrations (15.5 ± 18.8 nmol/L) than patients with normal gastric emptying (4.8 ± 5.7 nmol/L, P = 0.05) independently of reflux burden. Proton pump inhibitor use increased the proportion of unconjugated gastric bile acids. High lung bile concentrations were associated with an increased risk of hospitalization and longer hospital stays in RP patients (P < 0.05).DISCUSSION:Lung bile is almost universally present in symptomatic patients, and higher concentrations are associated with poorer respiratory outcomes.

Purification and characterization of phytase from Bacillus subtilis P6: Evaluation for probiotic potential for possible application in animal feed

AbstractThe antinutritional property of phytate is the main problem associated with food animals, but phytase‐producing probiotic strain could be the best alternative for resolving this problem. In the present study, phytase from probiotic strain Bacillus subtilis P6 was purified to homogeneity, which showed a relative molecular mass of 40 kDa on native and SDS‐PAGE. The purification fold of purified phytase was 86.99, with a specific activity of 104.39 U/mg protein. The purified enzyme showed optimum activity at 40°C and pH 6.0. Semi‐metal ions, such as K+ and Ca2+, slightly enhance the enzyme activity while Cu2+, Co2+, and Zn2+ prominently inhibited phytase activity. Purified phytase showed the highest substrate specificity toward its natural substrate phytate and did not hydrolyze other substrates having a phosphate bond. The purified enzyme exhibited strong proteolytic tolerance against trypsin and pepsin. Further, we evaluated the probiotic potential of B. subtilis and noted that it showed excellent resistance toward high acidic and bile concentrations. Subsequently, it revealed exceptional antimicrobial activity, good hydrophobicity, autoaggregation ability, nonhemolytic, and nonlecithinase activity. Additionally, B. subtilis P6 displayed susceptibility against major antibiotics. Owing to the excellent biochemical properties of phytase with notable probiotic characteristics, B. subtilis P6 may offer the possibility of being a promising candidate for the application in animal feed and food supplements. However, the in vivo use of strain secreting phytase needs to be studied in animals for its intended benefits

Structural Studies on the Shapeshifting Murine Norovirus.

Noroviruses are responsible for almost a fifth of all cases of gastroenteritis worldwide. The calicivirus capsid is composed of 180 copies of VP1 with a molecular weight of ~58 kDa. This coat protein is divided into the N-terminus (N), the shell (S) and C-terminal protruding (P) domains. The S domain forms a shell around the viral RNA genome, while the P domains dimerize to form protrusions on the capsid surface. The P domain is subdivided into P1 and P2 subdomains, with the latter containing the binding sites for cellular receptors and neutralizing antibodies. Reviewed here are studies on murine norovirus (MNV) showing that the capsid responds to several physiologically relevant cues; bile, pH, Mg2+, and Ca2+. In the initial site of infection, the intestinal tract, high bile and metal concentrations and low pH cause two significant conformational changes: (1) the P domain contracts onto the shell domain and (2) several conformational changes within the P domain lead to enhanced receptor binding while blocking antibody neutralization. In contrast, the pH is neutral, and the concentrations of bile and metals are low in the serum. Under these conditions, the loops at the tip of the P domain are in the open conformation with the P domain floating on a linker or tether above the shell. This conformational state favors antibody binding but reduces interactions with the receptor. In this way, MNV uses metabolites and environmental cues in the intestine to optimize cellular attachment and escape antibody binding but presents a wholly different structure to the immune system in the serum. To our knowledge, this is the first example of a virus shapeshifting in this manner to escape the immune response.

High presepsin concentrations in bile and its marked elevation in biliary tract diseases: A retrospective analysis

BackgroundPresepsin is a diagnostic and prognostic biomarker of both bacterial infection and sepsis; however, elevated presepsin levels have also been observed without sepsis. We conducted several analyses to evaluate the clinical laboratory parameters affecting presepsin levels. MethodWe analyzed the association between sequential organ failure assessment (SOFA) scores and plasma presepsin levels and then analyzed clinical laboratory parameters in 567 patients with univariate and multivariate regression analysis and analysis of covariance (ANCOVA). We also determined presepsin in the bile of 11 patients and examined the presepsin immunostaining in liver. ResultsSpearman’s rank correlation analysis with loge change revealed that presepsin levels were closely associated with loge-transformed SOFA score (ρ = 0.541), alkaline phosphatase (ALP); (ρ = 0.454) and gamma-glutamyl transferase; (ρ = 0.505). Multivariate regression analysis revealed that loge-transformed SOFA score (β-coefficient = 0.316), ALP level (β-coefficient = 0.380), and creatinine level (β-coefficient = 0.290) independently and significantly affected loge presepsin levels. ANCOVA revealed that presepsin levels were significantly higher in patients with hepatobiliary disease. Patients who presented with dilatation of the bile ducts and elevated ALP levels or total bilirubin levels exhibited high presepsin levels in the bile. Presepsin production in liver Kupffer cells was also confirmed by immunostaining. ConclusionPresepsin levels is correlated with the elevation of biliary enzymes in patients without renal dysfunction or sepsis. Additionally, presepsin exists with high concentrations in the bile and is positive in Kupffer cells.

The role of legume peptides released during different digestion stages in modulating the bioaccessibility of exogenous iron and zinc: An in-vitro study

The effects of legume protein fractions on Fe and Zn bioaccessibility remain equivocal to date, largely due to the protein’s structure and the presence of anti-nutritional compounds. We administered Fe and Zn salts with legume concentrates consisting mainly of albumin or globulin from lupin, pea and faba to in vitro gastrointestinal digestion. Under the fasted intestinal state, faba globulins were found to enhance Fe2+ and Zn solubility compared to control salts without legume proteins. Meanwhile, other fractions had no effect or significantly lowered Fe and Zn solubility. Under the fed intestinal state, the presence globulins enhanced Fe solubility versus the control, where protein solubilization due to high bile concentration likely played a role in circumventing precipitation. The lupin albumin fraction significantly enhanced Fe2+ and Zn solubility, whilst other fractions generally reduced Zn solubility under fed state. Our results highlight the complex role of legume proteins towards Fe and Zn solubility.

The influence of the ph and various concentrations of salt and bile on the growth of enterococci isolated from natural ecosystems

The article presents the results of the studies on ability of four un explored strains of enterococci isolated from the traditional Carpathian cheese to survive at different pH values under high concentrations of salt (sodium chloride) and bile. The lowp Hin the stomach and bileacid swhichen tering to the small in testine reduce the survival of bacteria, so the effectiveness of probiotics trains dependson a large extent on the irresistance to the sefactors. Saltisone of the maincomponents in the production of brinecheeses, asit influence on the enzymes activity during cheeseri pening and the formation of flavoring compounds, on the hydration of casein, and also on the shelf life of cheese. However, high concentrations of salt exhibit a bacterio staticeffect, sotheres istance of microbial cultures to saltcon centrations, which a repredicted by the technological process for brinecheeses, is really important. The results o fthe studyes tablished, that the tested strains of enterococci are not abletosurvive and exhibit growth properties at the value of pH 3 units. At the value of pH 4 units, only two strains E. durans SB18 and E. durans SB20 were ableto survive and exhibit good growth properties, as indicated by the increase in the optical density of the culture medium. At the value of pH 5, all the tested strains of enterococci showed growth properties, however, E. durans SB18 andE durans SB20 strains showed more significant growth than the control samples, in particular, the optical density of the medium increased, respectively, 9,8 and 10,8 times (p&lt;0.001). During the studying the resistance of enterococci to different concentrations of bile, it was found out that at 20% concentration the highest growth was shown by two strains of enterococci - E. durans SB18 andE. durans SB20, the optical density of the culture medium of the sestrains were higher compared to the control on 61,9 and 58,9% (p&lt;0.001), respectively. All the tested strains of enterococci were abletosurvive at the concentration of 3-6,5% sodium chloride for 21 days, indicating their suitability in using the minthe production of brinecheeses. Key words: Enterococcusdurans, E. faecium, optical density, bile, pH.

Bifidobacterial biofilm formation is a multifactorial adaptive phenomenon in response to bile exposure

In the current study, we show that biofilm formation by various strains and species belonging to Bifidobacterium, a genus that includes gut commensals with reported health-promoting activities, is induced by high concentrations of bile (0.5% (w/v) or higher) and individual bile salts (20 mM or higher), rather than by acid or osmotic stress. The transcriptomic response of a bifidobacterial prototype Bifidobacterium breve UCC2003 to such high bile concentrations was investigated and a random transposon bank of B. breve UCC2003 was screened for mutants that affect biofilm formation in order to identify genes involved in this adaptive process. Eleven mutants affected in their ability to form a biofilm were identified, while biofilm formation capacity of an insertional mutation in luxS and an exopolysaccharide (EPS) negative B. breve UCC2003 was also studied. Reduced capacity to form biofilm also caused reduced viability when exposed to porcine bile. We propose that bifidobacterial biofilm formation is an adaptive response to high concentrations of bile in order to avoid bactericidal effects of high bile concentrations in the gastrointestinal environment. Biofilm formation appears to be a multi-factorial process involving EPS production, proteins and extracellular DNA release, representing a crucial strategy in response to bile stress in order to enhance fitness in the gut environment.

Characterization, screening, and application of bacteria with probiotic properties isolated from the gut of Labeo calbasu (Hamilton)

Abstract Labeo calbasu is not reared in aquaculture because of the unavailability of proper feed and the risk of infection. The ability of probiotics to promote growth and immunological defense barriers in the gut has led to the use of autochthonous probiotic bacteria. Hence, the present study was conducted to screen potential probiotic bacteria from the gut of L. calbasu and to supplement the same to study the effect on growth and immunity. Strains with probiotic properties were assayed for exogenous enzyme production and identified based on phylogenetic analysis and nucleotide homology. Four of nine isolates showed promising antibacterial activity against Aeromonas hydrophila. The strains survived in relatively low pH and high bile concentrations and were investigated for hydrophobicity, autoaggregation, and coaggregation. Based on the positive results of this study, the LC1 and LC4 strains (analysed with 16S rRNA gene sequencing and showing similarity with Aneurinibacillus aneurinilyticus and Stenotrophomonas sp.) were further incorporated into diets to explore their probiotic effects on the growth performance and immunity of the fish. Administering the probiotics elevated growth parameters and benefitted the immune system by increasing the phagocytic index and decreasing the mortality rate with exposure to A. hydrophila.

Probiotic Bifunctionality of Bacillus subtilis-Rescuing Lactic Acid Bacteria from Desiccation and Antagonizing Pathogenic Staphylococcus aureus.

Live probiotic bacteria obtained with food are thought to have beneficial effects on a mammalian host, including their ability to reduce intestinal colonization by pathogens. To ensure the beneficial effects, the probiotic cells must survive processing and storage of food, its passage through the upper gastrointestinal tract (GIT), and subsequent chemical ingestion processes until they reach their target organ. However, there is considerable loss of viability of the probiotic bacteria during the drying process, in the acidic conditions of the stomach, and in the high bile concentration in the small intestine. Bacillus subtilis, a spore-forming probiotic bacterium, can effectively maintain a favorable balance of microflora in the GIT. B. subtilis produces a protective extracellular matrix (ECM), which is shared with other probiotic bacteria; thus, it was suggested that this ECM could potentially protect an entire community of probiotic cells against unfavorable environmental conditions. Consequently, a biofilm-based bio-coating system was developed that would enable a mutual growth of B. subtilis with different lactic acid bacteria (LAB) through increasing the ECM production. Results of the study demonstrate a significant increase in the survivability of the bio-coated LAB cells during the desiccation process and passage through the acidic environment. Thus, it provides evidence about the ability of B. subtilis in rescuing the desiccation-sensitive LAB, for instance, Lactobacillus rhamnosus, from complete eradication. Furthermore, this study demonstrates the antagonistic potential of the mutual probiotic system against pathogenic bacteria such as Staphylococcus aureus. The data show that the cells of B. subtilis possess robust anti-biofilm activity against S. aureus through activating the antimicrobial lipopeptide production pathway.

Investigation of bile tolerance and deconjugation ability of various Lactobacillus Casei group strains

Lactobacillus casei group is commonly used as probiotics. Various factors affect their viability in gastrointestinal tract. Twenty two strains of Lactobacillus casei group were assessed for bile tolerance and deconjugation attribute. All strains had shown moderate activity at 0% bile concentration. At 1% bile concentration CSCC 2607 has shown highest growth while remaining Lactobacillus strains have shown fair growth. At 1.5% bile concentration only seven Lactobacillus strains showed growth and ASCC 1521 showed highest activity. All seven strains were able to deconjugate both sodium glycocholate and sodium taurocholate at varying levels. ASCC 1520 showed lowest deconjugation activity for sodium glycocholate. All seven strains showed lower deconjugation of sodium taurocholate compared to sodium glycocholate. ASCC 290 was least capable of deconjugation of sodium taurocholate. When mixture of sodium glycocholate and sodium taurocholate having the similar molar ratio in human bile, was taken, all seven strains showed consistent cholic acid secretion. ASCC 1521 also showed highest cholic acid liberation while ASCC 1520 showed lowest deconjugation ability. This study suggests the importance to identify all the useful Lactobacillus strains which are able to tolerate and deconjugate, high bile concentration in order to study further for their therapeutic benefits.

In vitro evaluation of the probiotic candidates isolated from the gut of Clarias gariepinus with special reference to the in vivo assessment of live and heat-inactivated Leuconostoc mesenteroides and Edwardsiella sp.

Fish gut microbiota contains many potential probiotics that can be used in aquaculture. The aim of this study was to isolate beneficial probiotic bacteria from the gut of African catfish, Clarias gariepinus, and to evaluate the most suitable in vivo probiotic candidates. Eighty-nine gut bacterial isolates were screened for in vitro antibacterial activities against five common isolated fish pathogens, Aeromonas sobria, A. hydrophila, Pseudomonas aeruginosa, P. putida, and Staphylococcus aureus. Results found that nine out of 89 isolates had antibacterial activities with at least one pathogen. Two out of nine isolates demonstrated pathogenic effects following intraperitoneal injection. The remaining non-pathogenic seven strains were able to survive in high bile concentration (10%) and at different acidic pH values. Three out of seven strains were sensitive to all selected antibiotics. Four out of seven strains had amylase and protease activities. Based on 16S rRNA gene analysis, the isolated strains were identified as follows: Bacillus subtilis (6HN), B. amyloliquefaciens (7HN), B. cereus (29HN), Leuconostoc mesenteroides (13HN), Edwardsiella sp. (34HN), and Citrobacter freundii (24HN and 31HN). Comparative in vivo study of dietary supplementations of heat-inactivated and live L. mesenteroides (13HN) and Edwardsiella sp. (34HN) showed better improvements in growth, immunity, and the expression of myostatin (MSTN) and pituitary adenylate cyclase-activating polypeptide (PACAP) in the spleen of C. gariepinus of heat-inactivated probiotics than live one.

Encapsulation of beneficial probiotic bacteria in extracellular matrix from biofilm-forming Bacillus subtilis

Probiotics, live microbial supplements, are often incorporated into foods and beverages to provide putative health benefits. To ensure their beneficial effects, these organisms must survive processing and storage of food, its passage through the upper gastrointestinal tract (GIT), and subsequent chemical ingestion processes until they reach their target organ. However, there is considerable loss of viability of probiotic bacteria in the acidic conditions of the stomach and the high bile concentration in the small intestine. Bacillus subtilis, a spore-forming non-pathogenic bacterium, recently has gained interest in its probiotic properties; it can effectively maintain a favorable balance of microflora in the GIT. In addition, B. subtilis produces an extracellular matrix that protects it from stressful environments. We suggested that the extracellular matrix produced by B. subtilis could protect other probiotic bacteria and therefore potentially could be used as a vehicle for delivering viable probiotic cells to humans. Therefore, we developed a novel cultivation system that enables co-culturing of B. subtilis along with probiotic lactic acid bacteria (LAB) by increasing production of the extracellular matrix by B. subtilis cells. Moreover, we showed that B. subtilis improved survivability of LAB during food preparation, storage and ingestion. Therefore, we believe that the results of our study will provide a novel technique of using a natural system for preservation and delivery of probiotics to humans.

In Vitro Selection and Identification of Potential Probiotics Isolated from the Gastrointestinal Tract of Nile Tilapia, Oreochromis niloticus.

Fish gut bacteria can be used as probiotics for aquaculture. The aim of this study is to screen and identify beneficial probiotic bacteria from the gut of Nile tilapia, Oreochromis niloticus. Nine out of one hundred thirty-five isolates were non-pathogenic through intraperitoneal injection and had antibacterial activities with at least a strain from the five isolated fish pathogens, Aeromonas sobria, Aeromonas hydrophila, Pseudomonas aeruginosa, Pseudomonas putida, and Staphylococcus aureus. Further tests showed that such isolates can survive in the presence of high bile concentration (10%) and at different acidic pH values. A strains (14HT) was sensitive to all selected antibiotics, two strains were (9HT and 11HT) resistant to streptomycin and three strains (9HT, 11HT and 38HT) had resistance to two antibiotics. Four isolates (11HT, 33HT, 38HT and 41HT) had an amylase and a protease activities and one strain (47HT) showed only amylase activity. Based on 16S rRNA gene analysis, the isolated strains were identified as follows: Lactococcus lactis (8HT, 9HT, 11HT and 33HT); Enterococcus faecalis (14HT), Lysinibacillus sp. (38HT) and Citrobacter freundii (39HT, 41HT and 47HT).