DNA-protection and antioxidant properties of fermentates from Bacillus amyloliquefaciens B-1895 and Bacillus subtilis KATMIRA1933

Probiotic Bacillus amyloliquefaciens B-1895 Improved Growth of Juvenile Trout

The aim of this study was to evaluate a new Bacillus amyloliquefaciens B-1895 probiotic as a feed additive for farmed trout. Final weight, absolute and average daily gain of fish, and average daily growth rate were higher in the group that received the probiotic than in the control group (p<0.05). Moreover, the probiotic-fed trout had more intense growth rates than the control group (higher by 15.7%; p<0.05). A decrease in feed ratio was also observed in the group that received probiotic (25% decrease; p<0.05), indicating more efficient digestion and assimilation of feed. In general, the introduction of probiotic in the feed did not adversely affect the functional status of the fish. In young trout of the control group, when assessing the general chemical composition of the organism in the muscle tissue revealed significantly (p≤0.001) higher level of moisture content by 5.1% and lower by 11.0% dry matter content. In muscle, the protein content was higher by 1.33% (p≤0.001) and fat content by 2.1% (p≤0.001) in experimental fish. Generally, Lactobacilli, Enterococcus, Vibrio, Bacillus, and coliform bacteria were found in the intestinal samples of rainbow trout. Significant reliable difference (p≤0.05) between the samples of experimental and control groups was noted in the content of Bacillus bacteria. In the control group, 5.0±0.4×103 CFU/g was detected, while in the experimental group 8.4±0.8×104 CFU/g. Overall, the data indicate that probiotic bacteria B. amyloliquefaciens B-1895 has no adverse effect on selected microorganisms in the study fish.

Synbiotics and Their Antioxidant Properties, Mechanisms, and Benefits on Human and Animal Health: A Narrative Review

Antioxidants are often associated with a variety of anti-aging compounds that can ensure human and animal health longevity. Foods and diet supplements from animals and plants are the common exogenous sources of antioxidants. However, microbial-based products, including probiotics and their derivatives, have been recognized for their antioxidant properties through numerous studies and clinical trials. While the number of publications on probiotic antioxidant capacities and action mechanisms is expanding, that of synbiotics combining probiotics with prebiotics is still emerging. Here, the antioxidant metabolites and properties of synbiotics, their modes of action, and their different effects on human and animal health are reviewed and discussed. Synbiotics can generate almost unlimited possibilities of antioxidant compounds, which may have superior performance compared to those of their components through additive or complementary effects, and especially by synergistic actions. Either combined with antioxidant prebiotics or not, probiotics can convert these substrates to generate antioxidant compounds with superior activities. Such synbiotic-based new routes for supplying natural antioxidants appear relevant and promising in human and animal health prevention and treatment. A better understanding of various component interactions within synbiotics is key to generating a higher quality, quantity, and bioavailability of antioxidants from these biotic sources.

Beneficial Effects of Spore-Forming Bacillus Probiotic Bacteria Isolated From Poultry Microbiota on Broilers' Health, Growth Performance, and Immune System

Probiotics are known for their beneficial effects on poultry health and wellbeing. One promising strategy for discovering Bacillus probiotics is selecting strains from the microbiota of healthy chickens and subsequent screening for potential biological activity. In this study, we focused on three probiotic strains isolated from the gastrointestinal tract of chickens bred in different housing types. In addition to the previously reported poultry probiotic Bacillus subtilis KATMIRA1933, three strains with antimutagenic and antioxidant properties Bacillus subtilis KB16, Bacillus subtilis KB41, and Bacillus amyloliquefaciens KB54, were investigated. Their potential effects on broiler health, growth performance, and the immune system were evaluated in vivo. Two hundred newly hatched Cobb500 broiler chickens were randomly divided into five groups (n = 40). Four groups received a standard diet supplemented with the studied bacilli for 42 days, and one group with no supplements was used as a control. Our data showed that all probiotics except Bacillus subtilis KATMIRA1933 colonized the intestines. Treatment with Bacillus subtilis KB54 showed a significant improvement in growth performance compared to other treated groups. When Bacillus subtilis KB41 and Bacillus amyloliquefaciens KB54 were applied, the most significant immune modulation was noticed through the promotion of IL-6 and IL-10. We concluded that Bacillus subtilis KB54 supplementation had the largest positive impact on broilers' health and growth performance.

Antioxidant and antimutagenic properties of probiotic Lactobacilli determined using LUX-biosensors

The initial screening of probiotic strains in vitro, carried out by different methods, may omit strains that are promising from the point of view of biotechnology or, conversely, mark as promising strains those that will lose activity when transferred in vivo. It is known that the release of metabolites by probiotic bacteria, in particular, lactobacilli, is highly dependent on the biochemical context. In this work, we modified the method that was previously successfully used for the selection of probiotics for poultry, based on their antioxidant and DNA-protective properties. A comparison was made of this activity on standard media and on an artificial intestinal medium that mimics the intestines of a bird. As a result, three Lactobacillus strains were selected, which not only exhibit antioxidant and DNA-protective properties but also do not lose these activities in an artificial intestinal medium.

Gut microbiota of bats: pro-mutagenic properties and possible frontiers in preventing emerging disease

Bats are potential natural reservoirs for emerging viruses, causing deadly human diseases, such as COVID-19, MERS, SARS, Nipah, Hendra, and Ebola infections. The fundamental mechanisms by which bats are considered “living bioreactors” for emerging viruses are not fully understood. Some studies suggest that tolerance to viruses is linked to suppressing antiviral immune and inflammatory responses due to DNA damage by energy generated to fly. Our study reveals that bats' gut bacteria could also be involved in the host and its microbiota's DNA damage. We performed screening of lactic acid bacteria and bacilli isolated from bats' feces for mutagenic and oxidative activity by lux-biosensors. The pro-mutagenic activity was determined when expression of recA increased with the appearance of double-strand breaks in the cell DNA, while an increase of katG expression in the presence of hydroxyl radicals indicated antioxidant activity. We identified that most of the isolated bacteria have pro-mutagenic and antioxidant properties at the same time. This study reveals new insights into bat gut microbiota's potential involvement in antiviral response and opens new frontiers in preventing emerging diseases originating from bats.

Antimicrobial Activity of Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 Against Staphylococcus aureus Biofilms Isolated from Wound Infection

Staphylococcal wound infections range from mild to severe with life-threatening complications. The challenge of controlling such infections is related to bacterial biofilm formation, which is a major factor contributing to antibiotic resistance and infection recurrence. In this study, four clinical isolates of staphylococci species; two isolates of methicillin-resistant Staphylococcus aureus (MRSA) and two methicillin-sensitive Staphylococcus aureus (MSSA) isolates. The identification of bacterial species based on cell morphology, initial biochemical tests, and the VITEK2 system were used to confirm the clinical microbiological diagnosis. Antibiotic sensitivity testing showed that the isolated staphylococci were highly resistant to the following antibiotics, amoxicillin, penicillin G, cefotaxime, and methicillin. Combinations of cefotaxime with the cell-free supernatants (CFS) of Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895, each one separately showed complementary activity against the tested staphylococci. The co-aggregation capability of the tested bacilli as beneficial bacteria against isolated staphylococci was also evaluated. The data showed a strong co-aggregation with scores (+ 3, + 4) which were reported between the bacilli strains and the isolated staphylococci. Furthermore, the CFS of bacilli strains showed an inhibitory effect against biofilm-associated MRSA and MSSA. These findings confirmed the ability of beneficial bacteria to compete with the pathogens at the site of colonization or for the source of nutrients and, eventually, lead to inhibition of the pathogens' capability of causing a wound infection. Such beneficial bacteria could play an important role in future pharmaceutical and industrial applications.

Fermented Duckweed as a Potential Feed Additive with Poultry Beneficial Bacilli Probiotics

In this study, the duckweed varieties Lemna minor, Spirodela polyrhiza, and a commercially processed duckweed food supplement were investigated as potential substrates for the propagation of two probiotic Bacillus strains, B. subtilis KATMIRA1933 and B. amyloliquefaciens B-1895. Both L. minor and S. polyrhiza were found to be suitable substrates for the propagation of both bacilli, with 8.47-9.48 Log CFU/g and 10.17-11.31 Log CFU/g after 24 and 48 h growth on the substrates, respectively. The commercial duckweed product was a less favorable substrate, with growth reaching a maximum of 7.89-8.91 CFU/g after 24 h with no further growth after 48 h. Growth and adherence of the bacilli to the three products were confirmed via electron microscopy. These strains have demonstrated health-promoting benefits for poultry and thereby have the potential to enhance duckweed as an animal feed through the process of fermentation. Duckweed has been shown to be a promising alternative resource for protein and has the opportunity to become a valuable resource in multiple industries as a potential means to increase sustainability, food security, and reduce environmental impact.

Probiotic effect of Bacillus subtilis B-2998D, B-3057D, and Bacillus licheniformis B-2999D complex on sheep and lambs

Objectives:

Probiotics are well documented for their health benefits by developing a balanced intestinal microbiota and boosting immunity. The present study was conducted to determine the effects of a probiotic preparation Enzimsporin^TM (consisting of spore-forming bacteria Bacillus subtilis B-2998D, B-3057D, and Bacillus licheniformis B-2999D) on the biochemical, hematological, immunological parameters, intestinal microbiota, and growth dynamics of sheep and lambs.

Materials and Methods:

Enzimsporin was fed to lambs and sheep at different doses to determine the bacteria’s probiotic effects. Sheep were divided into three groups (six each), which received 0, 1, and 3 gm of Enzimsporin/per head/day, respectively, and two groups of lambs (10 each), who received 0 gm and 1 gm of Enzimsporin/per head/day for 30 days in addition to their regular ration. On day 30, blood samples were collected, followed by the determination of biochemical, hematological, and natural resistance indicators. Fecal samples were examined to determine the intestinal microflora, and animals were weighed daily to determine their growth dynamics.

Results:

Supplementation of probiotics (Enzimsporin^TM) improved the lambs’ body weight gain by 18.8%. Analysis of the clinical parameters showed improvements in the levels of total protein, globulins, and urea by 5.3%, 10.8%, and 6.2%, respectively, in the blood of probiotic-supplemented lambs. Similarly, an increment in the total protein, albumins, and globulins was observed in the sheep with Enzimsporin^TM supplementation. The decrease in bilirubin and cholesterol levels in the blood and increased bactericidal and phagocytic index in the sheep and lambs with probiotic supplementation indicated a positive influence of Enzimsporin^TM on the liver function and natural resistance. Furthermore, an increase in Lactobacillus and Bifidobacterium and a decrease in the Escherichia coli, Enterococcus, and Yeast in the fecal contents of experimental sheep and lambs indicated the potentiality of Enzimsporin^TM on maintaining good gut health.

Conclusion:

Spore-forming bacteria B. subtilis B-2998D, B-3057D, and B. licheniformis B-2999D can be used in feeding sheep and lambs of 2 months of age to increase body weight gain, improve intestinal microbiota, strengthen the immune system, and maintain normal metabolic processes.

Prebiotic, Probiotic, Antimicrobial, and Functional Food Applications of Bacillus amyloliquefaciens

Bacillus amyloliquefaciens belongs to the genus Bacillus and family Baciliaceae. It is ubiquitously found in food, plants, animals, soil, and in different environments. In this review, the application of B. amyloliquefaciens in probiotic and prebiotic microbes in fermentation, synthesis, and hydrolysis of food compounds is discussed as well as further insights into its potential application and gaps. B. amyloliquefaciens is also a potential microbe in the synthesis of bioactive compounds including peptides and exopolysaccharides. In addition, it can synthesize antimicrobial compounds (e.g., Fengycin, and Bacillomycin Lb), which makes its novelty in the food sector greater. Moreover, it imparts and improves the functional, sensory, and shelf life of the end products. The hydrolysis of complex compounds including insoluble proteins, carbohydrates, fibers, hemicellulose, and lignans also shows that B. amyloliquefaciens is a multifunctional and potential microbe which can be applied in the food industry and in functional food processing.

Oxalate-Degrading Bacillus subtilis Mitigates Urolithiasis in a Drosophila melanogaster Model

Kidney stone disease is a morbid condition that is increasing in prevalence, with few nonsurgical treatment options. The majority of stones are composed of calcium oxalate. Unlike humans, some microbes can break down oxalate, suggesting that microbial therapeutics may provide a novel treatment for kidney stone patients. This study demonstrated that Bacillus subtilis 168 (BS168) decreased stone burden, improved health, and complemented the microbiota in a Drosophila melanogaster urolithiasis model, while not exacerbating calcium oxalate aggregation or adhesion to renal cells in vitro. These results identify this bacterium as a candidate for ameliorating stone formation; given that other strains of B. subtilis are components of fermented foods and are used as probiotics for digestive health, strain 168 warrants testing in humans. With the severe burden that recurrent kidney stone disease imposes on patients and the health care system, this microbial therapeutic approach could provide an inexpensive therapeutic adjunct.

Kidney stones affect nearly 10% of the population in North America and are associated with high morbidity and recurrence, yet novel prevention strategies are lacking. Recent evidence suggests that the human gut microbiota can influence the development of nephrolithiasis, although clinical trials have been limited and inconclusive in determining the potential for microbially based interventions. Here, we used an established Drosophila melanogaster model of urolithiasis as a high-throughput screening platform for evaluation of the therapeutic potential of oxalate-degrading bacteria in calcium oxalate (CaOx) nephrolithiasis. The results demonstrated that Bacillus subtilis 168 (BS168) is a promising candidate based on its preferential growth in high oxalate concentrations, its ability to stably colonize the D. melanogaster intestinal tract for as long as 5 days, and its prevention of oxalate-induced microbiota dysbiosis. Single-dose BS168 supplementation exerted beneficial effects on D. melanogaster for as long as 14 days, decreasing stone burden in dissected Malpighian tubules and fecal excreta while increasing survival and behavioral markers of health over those of nonsupplemented lithogenic controls. These findings were complemented by in vitro experiments using the established MDCK renal cell line, which demonstrated that BS168 pretreatment prevented increased CaOx crystal adhesion and aggregation. Taking our results together, this study supports the notion that BS168 can functionally reduce CaOx stone burden in vivo through its capacity for oxalate degradation. Given the favorable safety profile of many B. subtilis strains already used as digestive aids and in fermented foods, these findings suggest that BS168 could represent a novel therapeutic adjunct to reduce the incidence of recurrent CaOx nephrolithiasis in high-risk patients.

IMPORTANCE Kidney stone disease is a morbid condition that is increasing in prevalence, with few nonsurgical treatment options. The majority of stones are composed of calcium oxalate. Unlike humans, some microbes can break down oxalate, suggesting that microbial therapeutics may provide a novel treatment for kidney stone patients. This study demonstrated that Bacillus subtilis 168 (BS168) decreased stone burden, improved health, and complemented the microbiota in a Drosophila melanogaster urolithiasis model, while not exacerbating calcium oxalate aggregation or adhesion to renal cells in vitro. These results identify this bacterium as a candidate for ameliorating stone formation; given that other strains of B. subtilis are components of fermented foods and are used as probiotics for digestive health, strain 168 warrants testing in humans. With the severe burden that recurrent kidney stone disease imposes on patients and the health care system, this microbial therapeutic approach could provide an inexpensive therapeutic adjunct.

Evaluation of an Industrial Soybean Byproduct for the Potential Development of a Probiotic Animal Feed Additive with Bacillus Species

Probiotics are gaining public attention for their application in animal husbandry due to their ability to promote growth and prevent infections. Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 are two spore-forming probiotic microorganisms that have been demonstrated to provide health benefits for poultry when supplemented into their diet. These strains can be propagated on a wide range of substrates, including soybean-derived byproducts from the food processing industry. Soybean-derived byproducts are often incorporated into animal feeds, but the value of an additive could potentially be increased by the addition of probiotic microorganisms, which may decrease production costs and reduce environmental impact. In this study, a soybean byproduct and a desalted version of this byproduct were evaluated as potential substrates for the growth of two probiotic bacilli species. Chemical analysis of these byproducts showed favorable carbohydrate, fat, and amino acid profiles, which were not affected by the desalting process. The desalted byproduct was further evaluated as a substrate for the growth of B. subtilis KATMIRA1933 and B. amyloliquefaciens B-1895 under solid-state conditions, and samples from this experiment were visualized by scanning electron microscopy. The results of this study indicate that the desalted soybean byproduct is a suitable substrate for the propagation of the two Bacillus species, which grew to numbers sufficient for the formulation of a probiotic animal feed additive.

Probiotic Potential of Lactic Acid Starter Cultures Isolated from a Traditional Fermented Sorghum-Millet Beverage

The purpose of this study was to establish the probiotic potential of lactic acid bacteria (LAB) starter cultures, Lb. plantarum MNC 21, L. lactis MNC 24, and W. confusa MNC 20, isolated from a traditionally fermented sorghum-millet beverage from Uganda. The cultures were examined for tolerance to acid and bile salts, bile salt hydrolase (BSH) activity, antibiotic susceptibility, biogenic amine production, mucin degradation, hydrophobicity, auto-aggregation, adherence to the ileum, coaggregation, and antimicrobial properties against selected pathogenic species. Lb. rhamnosus yoba 2012, a known probiotic, was the reference. The isolates were tolerant to acid (pH = 3) and bile (1%). W. confusa MNC 20 and Lb. plantarum MNC 21 exhibited medium BSH activity (11-15 mm diameter of hydrolysis zone) while L. lactis and Lb. rhamnosus yoba 2012 exhibited low BSH activity (<10 mm diameter of hydrolysis zone). All isolates lacked mucolytic activity. Lb. plantarum MNC 21 and W. confusa MNC 20 produced agmatine. The candidate and reference microorganisms were resistant to 10 of 21 and 5 of 21 antibiotics, respectively. The isolates exhibited hydrophobic, auto-aggregation and coaggregation properties. These three properties were exhibited more (p < 0.05) by the reference than the potential probiotics. The ability of the potential probiotics to attach onto the goat ileum (7.3-8.0 log cfu/cm²) was comparable to that of Lb. rhamnosus yoba 2012 (7.6 log cfu/cm²). The four LAB inhibited E. coli, S. aureus, and S. enterica to the same extent (p < 0.05). The findings indicated potential probiotic activity of the starter cultures. However, further in vivo examination of these isolates is required to confirm their probiotic capabilities.

Nutritional modulation of fertility in male poultry

The increased consumption of protein derived from poultry demands greater poultry production, but increased poultry production (meat and eggs) is dependent on the fertility of the parent flocks. Clearly, the fertility of poultry flocks is associated with the fertility of both males and females, but the low numbers of males used for natural or artificial insemination mean that their role is more important. Thus, enhancing the semen volume, sperm concentration, viability, forward motility, and polyunsaturated fatty acids in sperm, as well as protecting against oxidative damage, could help to optimize the sperm membrane functionality, mitochondrial activity, and sperm-egg penetration, and thus fertility. Therefore, this review summarizes the nutritional factors that could improve the fertility of poultry males as well as their associated mechanisms to allow poultry producers to overcome low-fertility problems, especially in aging poultry males, thereby obtaining beneficial impacts on the poultry production industry.

Method of preparation, visualization and ultrastructural analysis of a formulation of probiotic Bacillus subtilis KATMIRA1933 produced by solid-phase fermentation

Probiotic preparations are used in medical treatment and in agricultural practice. They modulate numerous activities in eukaryotic hosts, such as: inhibition of pathogenic microbiota; stimulation of immunological responses; and production of antioxidants, anti-mutagens, and DNA protectors. Also, probiotic bacteria are used as a preventive measure to prevent bacterial diseases of the gastrointestinal tract. Solid-phase fermentation is reported as being used in the production of probiotic formulations where a solid substratum, such as soy and oil meal, is utilized for the growth of beneficial microorganisms. However, there are insufficient reports in the literature related to methodological approaches enabling evaluation of the final products of solid-phase fermentation. We suggest a novel method enabling evaluation of probiotic solid-state fermentation dry powders and observation of their morphology, ultrastructure, and elucidation of the quantitative distribution of probiotic microorganisms in solid substrates using electron microscopy. •The method is intended for ultrastructure microphotography of dry substances - for example, ultrastructure of solid-phase fermentation products.•The method allows preserving the ultrastructure of substrates that are damaged when soaking.•The method does not require additional equipment and reagents and can be used in all laboratories using electron microscopy.

Biological Effects of C60 Fullerene Revealed with Bacterial Biosensor-Toxic or Rather Antioxidant?

Nanoparticles have been attracting growing interest for both their antioxidant and toxic effects. Their exact action on cells strongly depends on many factors, including experimental conditions, preparation, and solvents used, which have contributed to the confusion regarding their safety and possible health benefits. In order to clarify the biological effects of the most abundant fullerene C₆₀, its impact on the Escherichia coli model has been studied. The main question was if C₆₀ would have any antioxidant influence on the cell and, if yes, whether and to which extent it would be concentration-dependent. An oxidative stress induced by adding hydrogen peroxide was measured with an E. coli MG1655 pKatG-lux strain sensor, with its time evolution being recorded in the presence of fullerene C₆₀ suspensions of different concentrations. Optimal conditions for the fullerene C₆₀ solubilization in TWEEN 80 2% aqueous solution, together with resulting aggregate sizes, were determined. Results obtained for the bacterial model can be extrapolated on eukaryote mitochondria. The ability of C₆₀ to penetrate through biological membranes, conduct protons, and interact with free radicals is likely responsible for its protective effect detected for E. coli. Thus, fullerene can be considered as a mitochondria-targeted antioxidant, worth further researching as a prospective component of novel medications.

Effect of Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 on the productivity, reproductive aging, and physiological characteristics of hens and roosters

The study aims at investigating the effect of preparations of two bacilli strains on laying hens and roosters. Preparations were based on the strains Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895. Several groups of roosters and hens received a preparation based on either strain, or a mixture of both, from the first day to the last day of poultry in production. These preparations improved egg production, quality of sperm production, quality/hatchery of eggs, and slowed down the reproductive aging of hens. These observations were confirmed by the mathematical model proposed herein. At the molecular level, the slowing down of aging was confirmed by a decrease in the amount of mitochondrial DNA damage. Monitoring the physiological parameters of the experimental and control groups of birds showed that live weight gain in all experimental groups was higher than in the control group, and the reproductive organs of hens were more developed. There was also an improvement in the biochemical parameters of blood, the quality of the sperm of roosters, the laying of laying hens, and the morphological and biochemical parameters of the eggs. One of the most significant results is an increase in egg fertilization and a decrease in embryo death during the first 7 days of incubation.

Methods to Assess the Antioxidative Properties of Probiotics

Probiotics prove useful in correcting and preventing numerous health conditions, including those having severe impact on society, e.g., obesity and cancer. Notably, these capabilities of probiotics appear to be associated with their antioxidant properties. The mechanisms of antioxidant action of probiotics range from immediate biochemical scavenging of reactive substances to induction of signaling events leading to increased capacity of the host's cytoprotective systems. Since the antioxidant effects of probiotics significantly vary in types and details, a broad selection of methods of assessment of these properties is required in order to identify, characterize, and develop novel probiotics for medical purposes, as well as to explain the mechanisms of action of probiotics already in use in healthcare. This review revises the versatile toolbox, which can be used to assess the antioxidant properties of probiotics.

Bacillus Probiotic Supplementations Improve Laying Performance, Egg Quality, Hatching of Laying Hens, and Sperm Quality of Roosters

The study aims at elucidating the effect of bacilli probiotic preparations on the physiology of laying hens and roosters. Probiotic formulations were prepared as soybean products fermented by Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895. In this study, groups of male and female chickens were used. These groups received a probiotic preparation based on either B. subtilis KATMIRA1933 or B. amyloliquefaciens B-1895, or of a mixture of strains, from the first day to the age of 39 weeks. These preparations positively affected egg production, quality of sperm production, and quality and hatchery of eggs. Considering the simplicity and cost effectiveness of the soy-based probiotic preparation, these formulations should be considered as advantageous in modern livestock production.

The Use of Biosensors to Explore the Potential of Probiotic Strains to Reduce the SOS Response and Mutagenesis in Bacteria

A model system based on the Escherichia coli MG1655 (pRecA-lux) Lux-biosensor was used to evaluate the ability of the fermentates of eight probiotic strains to reduce the SOS response stimulated by ciprofloxacin in bacteria and mutagenesis mediated by it. Preliminary attempts to estimate the chemical nature of active components of the fermentates were conducted.

A bioluminescent test system reveals valuable antioxidant properties of lactobacillus strains from human microbiota

Oxidative stress cause serious damages in human organism resulting in multiple diseases. Antioxidant therapy includes diet, the use of chemical agents or commensal bacteria such as lactobacilli. This study aims to evaluate the antioxidant (AO) activity of cell-free culture supernatants of lactobacilli, isolated from different parts of the human body. A test system based on Escherichia coli MG1655 strains carrying plasmids encoding luminescent biosensors pSoxS-lux and pKatG-lux inducible by superoxide anion and hydrogen peroxide, respectively, was used to analyze cell-free culture supernatants of lactobacilli. Bioluminescent detection systems are suitable for quick screening of AO activity of lactobacilli. The majority of strains (51 out of 81) belonging to six different species demonstrated various levels of antioxidant activity. This activity was confirmed using the trolox equivalent method. The genome of one of the strains showing high AO activity was sequenced, and the genes putatively involved in AO capacity were determined. Potencies of standard AO and CFS from the most active Lactobacillus strains. Percentages of decrease in the detected luminescence (IAO%) in the presence of AO or CFS are presented. L. br.-L. brevis, L. pl. -L. plantarum, L. rh.-L. rhamnosus.

Comparative Genomics of Bacillus amyloliquefaciens Strains Reveals a Core Genome with Traits for Habitat Adaptation and a Secondary Metabolites Rich Accessory Genome

The Gram positive, non-pathogenic endospore-forming soil inhabiting prokaryote Bacillus amyloliquefaciens is a plant growth-promoting rhizobacterium. Bacillus amyloliquefaciens processes wide biocontrol abilities and numerous strains have been reported to suppress diverse bacterial, fungal and fungal-like pathogens. Knowledge about strain level biocontrol abilities is warranted to translate this knowledge into developing more efficient biocontrol agents and bio-fertilizers. Ever-expanding genome studies of B. amyloliquefaciens are showing tremendous increase in strain-specific new secondary metabolite clusters which play key roles in the suppression of pathogens and plant growth promotion. In this report, we have used genome mining of all sequenced B. amyloliquefaciens genomes to highlight species boundaries, the diverse strategies used by different strains to promote plant growth and the diversity of their secondary metabolites. Genome composition of the targeted strains suggest regions of genomic plasticity that shape the structure and function of these genomes and govern strain adaptation to different niches. Our results indicated that B. amyloliquefaciens: (i) suffer taxonomic imprecision that blurs the debate over inter-strain genome diversity and dynamics, (ii) have diverse strategies to promote plant growth and development, (iii) have an unlocked, yet to be delimited impressive arsenal of secondary metabolites and products, (iv) have large number of so-called orphan gene clusters, i.e., biosynthetic clusters for which the corresponding metabolites are yet unknown, and (v) have a dynamic pan genome with a secondary metabolite rich accessory genome.