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Yogurt and acidophilus milk that contain Lactobacillus acidophilus could promote human health because L. acidophilus can inhibit enteric and food-borne microbial pathogens. To evaluate the stability of diary L. acidophilus cultures, we studied whether some diary lactobacilli could be inhibited by phages or bacteriocins released by other dairy lacto...
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... and morphology of y8. The infection cycle of phage y8 was characterized by its one-step growth curve ki- netics (Fig. 3). Data obtained from two independent experi- ments indicated a latent period of 30 min and a rise period of 30 to 40 min. The burst size was about 100 phages per cell. Sensitivities of y8 to heat and chloroform were tested with the crude, bacterium-free broth lysate. The heat sensitivity of y8 was determined at 40 to 70C. The same phage ...
Citations
... Within the screening and of the tested concentrations, 5 μg/ml to 20 μg/ml mitomycin C often showed the best results, although these values are high, compared to other studies using mitomycin C as prophage inducer. Usually, mitomycin C is added, due to its toxicity at higher concentrations, in much smaller amounts (0.1 μg/ml to a maximum of 2 μg/ml (final concentration)) in similar experimental settings with different LAB like miscellaneous lactobacilli [15,30], Lactococcus lactis [13] and Streptococcus pyogenes [31]. ...
Background
Lactic acid bacteria (LAB) are used as starters in a wide variety of food fermentations. While the number of reports of phages infecting other LAB steadily increased over the years, information about phage associated with Latilactobacillus sakei, a frequently used meat starter, remains scarce.
Results
In this study, a predictive genomic analysis of 43 Latilactobacillus sakei genomes revealed the presence of 26 intact, eleven questionable and 52 incomplete prophage sequences across all analysed genomes with a range of one to five predicted prophage sequences per strain. Screening 24 sakei strains for inducible prophages by utilising UV light or mitomycin C, we identified seven lysogenic strains showing lysis after induction during subsequent growth monitoring.
Electron microscopic analysis revealed fully assembled virions in the purified lysates of four samples, thus confirming successful prophage induction. All virions featured icosahedral, isomeric heads and long, most likely non-contractile tails indicating siphoviruses. By performing phylogenetic analyses with various marker genes as well as full prophage sequences, we displayed a remarkably high diversity of prophages, that share a similar gene module organisation and six different chromosomal integration sites were identified. By sequencing viral DNA purified from lysates of Latilactobacillus sakei TMW 1.46, we demonstrate that simultaneous induction of multiple prophages is possible.
Conclusions
With this work, we not only provide data about the incidence of prophages harboured by the meat starter Latilactobacillus sakei, we also demonstrated their potential to impact growth of their host after induction, as well as forming seemingly fully assembled virions.
... Bacteriophage contents of LAB strains were determined according to the methods of Kılıç et al. and Trevors et al. [34,35]. Cultures incubated overnight (18 h) were passaged as 60 µl into 3 ml of MRS-C medium (2.5 ml of 10 mM CaCl 2 , 250 ml of MRSB). ...
This study aims to identify lactic acid bacteria (LAB) isolated from honeybees (Apis mellifera workers and larvae) in detail and to determine their functional probiotic properties. A total of 11 strains were classified based on morphological and biochemical characteristics. Preliminary probiotic properties of strains, that were molecularly identified using 16 S rRNA, such as antimicrobial activity, tolerance to digestive conditions, aggregation ability, were investigated. The antimicrobial properties of strains were tested against a wide range of human pathogens. All strains that showed γ-hemolysis and did not contain bacteriophages were considered safe. The strains’ survivability checked for 0.3% bile and 3.0-7.8 pH contents was promising. The highest autoaggregation ranged from 14.7 to 30.76% after 4 h. Tested LAB strains markedly exhibited coaggregation with Listeria monocytogenes and Escherichia coli. According to the results, tested bacteria showed significant antagonistic effects against pathogens, and positive probiotic characteristics compatible with in vitro gastrointestinal tract conditions. The results suggest that Apis mellifera LAB symbionts may have a probiotic potential, and be effective and safe candidates for human use. This study provides an addition to the development of the current knowledge by defining in detail honeybee-associated bacteria and determining their probiotic potential.
... For one, despite being a metabolic burden on the cell (Ramisetty & Sudhakari, 2019), the presence of a prophage in the host genome can confer an evolutionary advantage to this host -e.g., encoding genes for multi-drug resistant pumps, outer membrane proteases, or toxic membrane polypeptides (Ramisetty & Sudhakari, 2019;Wang & Wood, 2016). Secondly, the induction of a prophage can lead to rapid changes in microbial communities in a given environment, or to premature cell lysis and the subsequent loss of an entire production batch in industrial applications -a problem often encountered in the dairy industry (De Paepe et al., 2016;Kilic et al., 1996). ...
Methanotrophs are a unique class of bacteria with the ability to metabolize single-carbon compounds such as methane. They play an important role in the global methane cycle and have great potential as industrial platforms for the bioconversion of methane from industrial waste streams into valuable products, such as biofuels and bioplastics. However, many aspects of methanotroph biology have yet to be elucidated, including the prevalence and impact of lysogenized bacteriophages (phages), which can greatly affect both the ecology and the industrial performance of these bacteria. The present study investigates the presence of putative prophages in three gammaproteobacterial (Methylobacter marinus A45, Methylomicrobium album BG8, Methylomonas denitrificans FJG1) and two alphaproteobacterial (Methylosinus trichosporium OB3b, Methylocystis sp. Rockwell) methanotrophs using four programs predicting putative phage sequences (PhageBoost, PHASTER, Phigaro, and Island Viewer). Mitomycin C was used to trigger induction of prophages, which was monitored through infection dynamics. Successfully induced phages from M. marinus A45 (MirA1, MirA2), M. album BG8 (MirB1), and M. trichosporium OB3b (MirO1) were isolated and characterized using transmission electron microscopy. Subsequently, bioinformatic analyses (BLAST and phylogenetics) were performed on three induced phages to obtain a profile of their respective genetic makeup. Their broad diversity and differences from previously known phages, based on whole genome and structural gene sequences, suggest they each represent a new phage family, genus and species: "Britesideviridae Inducovirus miraone", "Patronusviridae Enigmavirus miratwo", and "Kainiviridae Tripudiumvirus miroone" represented by isolates MirA1, MirA2, and MirO1, respectively.
... It is one of the only two obligatory bacteria in association with the bacterial species Lactobacillus delbrueckii subsp. bulgaricus for the manufacture of yogurt [Kiliç et al. 1996]. ...
Currently, the identification from genomic sequences of strains of a bacterial species present in a sample remains a complex and time consuming process. This difficulty comes from the genomic similarity between these strains. However, being able to differentiate them quickly is crucial in many fields, whether in agri-food (such as Streptococcus thermophilus) or in public health.Recently, the third generation of sequencing technologies, and more specifically the Oxford Nanopore Technologies sequencers, make it possible to obtain long but erroneous sequences from samples containing bacterial strains. These reads contain more information than the short reads from the second generation. However, currently, there are still few bioinformatics softwares developed to identify bacterial strains from erroneous long reads.This thesis therefore proposes a new method of bacterial strain identification based on the assumption that a nanopore read is long enough to distinguish one strain (or group of strains) from others. This method uses a particularly compact indexing technique of a known genome database. It also relies on the use of a spaced seed in order to search for sequences in the index while being less sensitive to long reads errors. The method is implemented in a software called ORI (Oxford nanopore Reads Identification) which has shown robust bacterial identification results on real data of Streptococcus thermophilus.
... In addition, S. thermophilus is the most representative subspecies of Streptococcus and is difficult to observe in the stomach unless ingested as a probiotic [81][82][83][84]. It also acts synergistically with L. bulgaricus and has been shown to be the safest probiotic [85]. Therefore, based on the results of previous studies and this study, we suggest the therapeutic potential of probiotic formulations based on S. thermophilus and L. bulgaricus, focusing on S. salivarius, for subjects with type P enterotype [86]. ...
Probiotics can be used as a nutritional strategy to improve gut homeostasis. We aimed to evaluate the intestinal microbiota profile of 18 subjects after ingestion of probiotic yogurt powder (PYP) based on enterotype. The subjects were classified into three enterotypes according to their microbial community: Bacteroides (n = 9, type B), Prevotella (n = 3, type P), and Ruminococcus (n = 6, type R). We performed controlled termination in a transient series that included a control period of three weeks before probiotic intake, PYP intake for three weeks, and a three-week washout period. Fecal microbiota composition was analyzed by sequencing the V3–V4 super variable region of 16S rRNA. Based on the Bristol stool shape scale, abnormal stool shape improved with PYP intake, and bowel movements were activated. The abundance of Faecalibacterium, Eggerthella, and Leuconostoc, which ferment and metabolize glucose, showed a strong correlation with type B Bacteroides, and glucose metabolism improvement was observed in all type B subjects. Alkaline phosphatase was significantly improved only in type B. In addition, the abundance of type B Bacteroides showed a negative correlation with that of Lactobacillus. The abundance of Streptococcus, Agathobacter, and Christensenella, which are involved in lipid metabolism, showed a strong correlation with that of type P Prevotella, and triglyceride metabolism improvement was observed in all type P subjects. The gut microbiota showed only short-term changes after PYP intake and showed resilience by returning to its original state when PYP intake was interrupted. In summary, the different responses to PYP intake may result from the different enterotypes and associated strains; therefore, the probiotic composition should be adjusted based on the individual enterotype.
... There are many species in Streptococcus at genus level, among which S. thermophilus is a probiotic that is generally used in the production of yogurt. 49 However, it is unlikely that the increased Streptococcus seen in the AD group is S. thermophilus because almost all probiotics sold in Korea contain Lactobacillus and Bifidobacterium. We selected S. mitis for the in vitro study because previous study has reported that previous study have shown that it is present in not only the oral but also the intestines, 50 moreover S. mitis induces IL-6 production. ...
Purpose:
Interleukin (IL)-17 variants and perturbations in the gut microbiota may influence the development of atopic dermatitis (AD). However, unifying principles for variants of host and microbe interaction remains unclear. We sought to investigate whether IL-17 variants and gut microbiota affect the development of AD in infancy.
Methods:
Composition of the gut microbiota was analyzed in fecal samples from 99 normal healthy and 61 AD infants at 6 months of age. The associations between total immunoglobulin E (IgE), the scoring atopic dermatitis (SCORAD), short-chain fatty acids, transcriptome and functional profile of the gut measured in these subjects and Streptococcus were analyzed. IL-6 and IL-8 in the human intestinal epithelial cell line (HIEC-6) were measured after stimulation of IL-17 and Streptococcus mitis.
Results:
In this study, Streptococcus was enriched in infants with AD and was higher in those with the GA + AA of IL-17 (rs2275913) variant. Streptococcus was positively correlated with IgE and SCORAD in infants with AD and GA + AA of IL-17. Butyrate and valerate were negatively correlated with Streptococcus and were decreased in infants with AD and GA + AA. Bacterial genes for oxidative phosphorylation induced by reduced colonization of Clostridium were decreased compared with normal and GG. In transcriptome analysis, lactate dehydrogenase A-like 6B was higher in infants with AD compared with healthy infants. IL-6 and IL-8 were increased in IL-17 and/or S. mitis-stimulated HIEC-6 cells.
Conclusions:
These findings suggest that increased Streptococcus and A allele of IL-17 (rs2275913) may contribute to the pathogenesis of AD via modulation of the immune system in infancy.
... One representative strain (L. crispatus CRI4) was subjected to the induction of lysogenic bacteriophages according to previous studies (Kiliç et al., 1996;Raya & H'bert, 2009). A total of 200 µL of the culture was initially inoculated in 5 mL of Man-Rogosa-Sharpe medium. ...
Background
Lactobacillus crispatus is the dominant species in the vaginal microbiota associated with health and considered a homeostasis biomarker. Interestingly, some strains are even used as probiotics. However, the genetic mechanisms of L. crispatus involved in the control of the vaginal microbiome and protection against bacterial vaginosis (BV) are not entirely known. To further investigate these mechanisms, we sequenced and characterized the first four L. crispatus genomes from vaginal samples from Brazilian women and used genome-wide association study (GWAS) and comparative analyses to identify genetic mechanisms involved in healthy or BV conditions and selective pressures acting in the vaginal microbiome.
Methods
The four genomes were sequenced, assembled using ten different strategies and automatically annotated. The functional characterization was performed by bioinformatics tools comparing with known probiotic strains. Moreover, it was selected one representative strain ( L. crispatus CRI4) for in vitro detection of phages by electron microscopy. Evolutionary analysis, including phylogeny, GWAS and positive selection were performed using 46 public genomes strains representing health and BV conditions.
Results
Genes involved in probiotic effects such as lactic acid production, hydrogen peroxide, bacteriocins, and adhesin were identified. Three hemolysins and putrescine production were predicted, although these features are also present in other probiotic strains. The four genomes presented no plasmids, but 14 known families insertion sequences and several prophages were detected. However, none of the mobile genetic elements contained antimicrobial resistance genes. The genomes harbor a CRISPR-Cas subtype II-A system that is probably inactivated due to fragmentation of the genes csn2 and cas9 . No genomic feature was associated with a health condition, perhaps due to its multifactorial characteristic. Five genes were identified as under positive selection, but the selective pressure remains to be discovered. In conclusion, the Brazilian strains investigated in this study present potential protective properties, although in vitro and in vivo studies are required to confirm their efficacy and safety to be considered for human use.
... This constitutes a rich reservoir for the development of many microorganism-infecting viruses. Studies have reported the presence of viruses that infect bacteria (bacteriophages) and yeast in plenty of fermented food products, including wine, meat, cheese, yoghurt, sourdough, sauerkraut, kimchi, soybean, and cocoa (Auad et al., 1997;Barrangou et al., 2002;Foschino et al., 2005;Illeghems et al., 2012;Kiliç et al., 1996;Kleppen et al., 2012a;Pringsulaka et al., 2011;Umene et al., 2009). In general, bacteriophages are considered harmful by decreasing the fermentative capacity of lactic acid bacteria (LAB) and yeasts, occasionally resulting in complete fermentation failure. ...
... The first LAB phage report was published 85 years ago, a streptococci attack-phage in cheese (Whitehead and Hunter, 1947). Posteriorly, the presence of phage was widely reported during lactic fermentation (e.g., sauerkraut, yogurt, natto, and cucumber) (Barrangou et al., 2002;Brussow et al., 1994;Kiliç et al., 1996;Kleppen et al., 2012b;Lu et al., 2003b;McIntyre et al., 1991;Quiberoni et al., 2003;Saxelin et al., 1986;Umene and Shiraishi, 2013). Phage attack was frequently associated with fermentation failure until complete loss of the product batch due to unfeasibility of starter cultures (Quiberoni et al., 2003). ...
... Yoghurt Kiliç et al. (1996); Auad et al., (1997 Yoghurt (Bendadis et al., 1990); (Brussow et al., 1994); (Quiberoni et al., 2003); (Ishlimova et al., 2012); (Ma et al., 2014) Cheese (Whitehead and Hunter, 1947); (Brussow et al., 1994); (Quiberoni et al., 2006); (Zinno et al., 2010) markets in the city of Mariana, Brazil. This area suffered an environmental disaster in 2015 when a rupture of an ore dam adversely affected water, soil, and air quality. ...
The emergence of Coronavirus disease 2019 as a global pandemic has increased popular concerns about diseases caused by viruses. Fermented foods containing high loads of viable fungi and bacteria are potential sources for virus contamination. The most common include viruses that infect bacteria (bacteriophage) and yeasts reported in fermented milks, sausages, vegetables, wine, sourdough, and cocoa beans. Recent molecular studies have also associated fermented foods as vehicles for pathogenic human viruses. Human noroviruses, rotavirus, and hepatitis virus have been identified in different fermented foods through multiple routes. No severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) virus or close members were found in fermented foods to date. However, the occurrence/persistence of other pathogenic viruses reveals a potential vulnerability of fermented foods to SARS-CoV-2 contamination. On the other side of the coin, some bacteriophages are being suggested for improving the fermentation process and food safety, as well as owing potential probiotic properties in modern fermented foods. This review will address the diversity and characteristics of viruses associated with fermented foods and what has been changed after a short introduction to the most common next generation sequencing platforms. Also, the risk of SARS-CoV-2 transmission via fermented foods and preventive measures will be discussed.
... A culture of the bacterium was grown by inoculating 5 mL of MRS medium, supplemented with 0.1% TWEEN1 80 (Sigma-Aldrich). Inductions were performed following published protocols [53,54]. Briefly, cultures were grown overnight at 35˚C with 5% CO 2 . 1 mL of the overnight culture was centrifuged at 10,000g for two minutes. ...
Bacteriophages (phages) play a key role in shaping microbial communities, including those of the human body. Phages are abundant members of the urogenital tract, most often persisting through the lysogenic life cycle as prophages integrated within the genomes of their bacterial hosts. While numerous studies of the urogenital microbiota have focused on the most abundant bacterial member of this niche–Lactobacillus species–very little is known about Lactobacillus phages. Focusing on Lactobacillus jensenii strains from the urinary tract, we identified numerous prophages related to the previously characterized Lv-1 phage from a vaginal L. jensenii strain. Furthermore, we identified a new L. jensenii phage, Lu-1. Evidence suggests that both phages are abundant within the urogenital tract. CRISPR spacer sequences matching to Lv-1 and Lu-1 prophages were identified. While first detected in urinary isolates, the Lu-1 phage was also discovered in L. jensenii isolates from vaginal and perineal swabs, and both phages were found in metagenomic data sets. The prevalence of these phages in the isolates suggests that both phages are active members of the urogenital microbiota.
... Antimicrobial activity: Agar spot test method [16][17] and agar well diffusion method 18 were used to detect of inhibitory activity of Lactobacillus spp. These assays were performed in duplicate. ...
This research was carried out to isolate and identify thermotolerant lactobacilli from broiler chicken gastrointestinal tract from Dhaka, Bangladesh. Twenty five thermotolerant Lactobacillus strains were isolated and identified as Lactobacillus species based on cultural characteristics, biochemical tests, and sugar fermentation. The probiotic are a live microbial feed supplements which positively affects the health of the host animal by improving its intestinal balance.The results showed only four among twenty five isolates were highly responded to probiotic criteria such as low pH tolerance (2.5), bile salt tolerance (2%) and sodium chloride salt tolerance (5%) in vitro, and were identified strains as Lactobacillus plantarum img-02, Lactobacillus plantarum img-08, Lactobacillus plantarum img-10 and Lactobacillus acidophilus img-14 according to Bergey’s Manual of Systematic Bacteriology. Four isolates grow enough at 45°C and two isolates (Lactobacillus plantarum img-10 and Lactobacillus acidophilus img-14) heat stable at 60°C for 30 min. All the strains were showed protease activity on skim milk agar. These strains were resistance to commercial antibiotic ciprofloxacin, gentamycin, imipenem and penicillin G but sensitive to ampicillin, doxycycline, erythromycin and tetracycline; also have antimicrobial activity against common pathogen such as ATCC of Salmonella enteritidis, Staphylococcus aureus, Listeria monocytogenes, Shigella flexneri, Bacillus cereus, Klebsiella pneumonia, Escherichia coli (environmental isolates), Aspergillus flavus and Candida albicans. This study concludes that these isolates may be used as potential candidate as probiotic poultry feed. Bangladesh J Microbiol, Volume 36 Number 2 December 2019, pp 63-68
