Draft Genome Sequences of Three Virulent Streptococcus thermophilus Bacteriophages Isolated from the Dairy Environment in the Veneto Region of Italy

ABSTRACT Streptococcus thermophilus , a very important dairy species, is constantly threatened by phage infection. We report the genome sequences of three S. thermophilus bacteriophages isolated from a dairy environment in the Veneto region of Italy. These sequences will be used for the development of new strategies to detect and control phages in dairy environments. </jats:p

Short communication: Comparison of growth kinetics at different temperatures of Streptococcus macedonicus and Streptococcus thermophilus strains of dairy origin

Within the genus Streptococcus, S. thermophilus and S. macedonicus are the 2 known species related to foods. Streptococci are widely used as starter cultures to rapidly lower milk pH. As S. macedonicus has been introduced quite recently, much less information is available on its technological potential. Because temperature is an important factor in fermented food production, we compared the growth kinetics over 24 h of 8 S. thermophilus and 7 S. macedonicus strains isolated from various dairy environments in Italy, at 4 temperatures, 30\ub0C, 34\ub0C, 37\ub0C and 42\ub0C. We used the Gompertz model to estimate the 3 main growth parameters; namely, lag phase duration (\u3bb), maximum growth rate (\ub5max), and maximum cell number at the stationary phase (Nmax). Our results showed significant differences in average growth kinetics between the 2 species. Among the strains tested, 37\ub0C appeared to be the optimal temperature for the growth of both species, particularly for S. macedonicus strains, which showed mean shorter lag phases and higher cell numbers compared with S. thermophilus. Overall, the growth curves of S. macedonicus strains were more similar to each other whereas S. thermophilus strains grew very differently. These results help to better define and compare technological characteristics of the 2 species, in view of the potential use of S. macedonicus in place of S. thermophilus in selected technological applications

X-SRAM: Enabling In-Memory Boolean Computations in CMOS Static Random Access Memories

Silicon-based Static Random Access Memories (SRAM) and digital Boolean logic have been the workhorse of the state-of-art computing platforms. Despite tremendous strides in scaling the ubiquitous metal-oxide-semiconductor transistor, the underlying \textit{von-Neumann} computing architecture has remained unchanged. The limited throughput and energy-efficiency of the state-of-art computing systems, to a large extent, results from the well-known \textit{von-Neumann bottleneck}. The energy and throughput inefficiency of the von-Neumann machines have been accentuated in recent times due to the present emphasis on data-intensive applications like artificial intelligence, machine learning \textit{etc}. A possible approach towards mitigating the overhead associated with the von-Neumann bottleneck is to enable \textit{in-memory} Boolean computations. In this manuscript, we present an augmented version of the conventional SRAM bit-cells, called \textit{the X-SRAM}, with the ability to perform in-memory, vector Boolean computations, in addition to the usual memory storage operations. We propose at least six different schemes for enabling in-memory vector computations including NAND, NOR, IMP (implication), XOR logic gates with respect to different bit-cell topologies $-$ the 8T cell and the 8$^+$T Differential cell. In addition, we also present a novel \textit{`read-compute-store'} scheme, wherein the computed Boolean function can be directly stored in the memory without the need of latching the data and carrying out a subsequent write operation. The feasibility of the proposed schemes has been verified using predictive transistor models and Monte-Carlo variation analysis.Comment: This article has been accepted in a future issue of IEEE Transactions on Circuits and Systems-I: Regular Paper

In vitro Probiotic Potential and Anti-cancer Activity of Newly Isolated Folate-Producing Streptococcus thermophilus Strains

Most probiotic strains commercially available today are lactic acid bacteria. Within this functional group, Streptococcus thermophilus is a thermophilic species widely used as starter culture for a huge number of dairy products. Besides being rapid acidifiers, many S. thermophilus strains are able to produce and release folate during growth but, unfortunately, they are seriously impaired during passage through the human gastrointestinal tract. In this work, we studied eight S. thermophilus strains isolated from dairy environments in Italy, which already had shown good technological properties, to evaluate their possible probiotic potential and cytotoxicity against cancer cells in vitro. All strains were also evaluated for some health-related properties such as susceptibility to most common antibiotics, hemolytic activity, resistance to simulated gastrointestinal conditions, bile salts hydrolytic activity, production of folate, adhesion to HT-29 human colorectal adenocarcinoma cells and cytotoxic activity against cancer cells and production of biogenic amines. Results revealed that two fast acidifying S. thermophilus strains were found to possess in vitro probiotic properties along with anticancer activity and production of folate. These properties resulted similar and, in some cases, superior to those of Lactobacillus rhamnosus GG, a well-known commercial probiotic strain. These findings encourage further in vivo studies to evaluate the actual health benefits of these strains on the human host

Comparative evaluation of cheese whey microbial composition from four Italian cheese factories by viable counts and 16S rRNA gene amplicon sequencing

The microbiota of cheese whey from four dairy companies located in the North-East of Italy was evaluated during winter and spring using both culture-dependent and culture-independent methods. Although no significant differences were observed (p > 0.05) for any of the six microbial categories analysed by plate counting among the dairy companies, significant differences at the family and genus level were revealed by linear discriminant analysis (LDA). In particular, variations in the abundance of the families Pseudomonadaceae and Enterobacteriaceae, as well as of the genus Acinetobacter were observed and positively correlated with plate count results (p < 0.05). The combined use of culture-dependent and culture-independent approaches gave a better description of the hygienic conditions and food safety aspects and could therefore be suggested as a useful integrated approach. \ua9 2020 Elsevier Lt

Characterization and Assessment of Health-related Probiotic Properties of Newly Isolated Lactic Acid Bacteria and Study of their Technological Potential by In-silico, In-vitro, and In-vivo Approaches

Lactic Acid Bacteria (LAB) are the most frequently probiotics used. Within this functional group, Streptococcus thermophilus is a thermophilic species widely used as a starter culture for a huge number of dairy products. Besides being rapid acidifiers, many S. thermophilus strains can produce and release folate during growth. S. macedonicus is another homofermentative lactic acid bacterium (LAB) which was first isolated from a typical Greek cheese obtained by natural fermentation in Macedonia. Some Streptococcus macedonicus strains have revealed some interesting properties, such as proteolytic activity, production of bacteriocins against food pathogens, production of exopolysaccharides and tolerance to stress associated with food processing. Lactobacilli also as a member of LAB identified as GRAS and used as a commercial starter in fermented dairy products or as probiotics related to human health. They can play significant roles in different ways such as inhibition of pathogens, anti-cancer activity and different vitamins production in human. Given this point, this thesis has aimed to identify and select some new potential probiotic-technological strains of LAB which recently were isolated from different sources through genomic and physiological studies to be used in human health and food industry. All the strains were evaluated for different technological aspects such as acidification activity and fermentation on different sugars. The genomes of strains were sequenced and applied for in-silico analysis to get enough information about their safety and application in technology and human health. On the other side, the interesting strains from technological part were selected to be evaluated for different in-vitro probiotic properties such as antibiotic susceptibility, hemolytic activity, resistance to simulated gastrointestinal conditions, bile salts hydrolysis activity, different vitamins production, adhesion to HT-29 human epithelial cell and anti-cancer activity against colorectal cancer cells (HT-29). Based on results from in-vitro probiotic characterization, strains Lactobacillus paracasei DTA81 and S. thermophilus TH982 were chosen for in-vivo experiments using the laboratory mice. The results of this study revealed that strain L. paracasei DTA81 was found to possess in-vitro and in-vivo probiotic properties besides lowering the blood cholesterol and Light Density Lipid (LDL) as well as Fasting Blood Sugar (FBS). Lactobacillus paracasei DTA81 had already indicated interesting technological traits such as growing on all different sugars including some prebiotics as well

Probiotics, Prebiotics, and Their Application in the Production of Functional Foods

Food biotechnology innovation and development reached an estimated growth tendency rate of 28% per year [...

Characterization and Assessment of Health-related Probiotic Properties of Newly Isolated Lactic Acid Bacteria and Study of their Technological Potential by In-silico, In-vitro, and In-vivo Approaches

Lactic Acid Bacteria (LAB) are the most frequently probiotics used. Within this functional group, Streptococcus thermophilus is a thermophilic species widely used as a starter culture for a huge number of dairy products. Besides being rapid acidifiers, many S. thermophilus strains can produce and release folate during growth. S. macedonicus is another homofermentative lactic acid bacterium (LAB) which was first isolated from a typical Greek cheese obtained by natural fermentation in Macedonia. Some Streptococcus macedonicus strains have revealed some interesting properties, such as proteolytic activity, production of bacteriocins against food pathogens, production of exopolysaccharides and tolerance to stress associated with food processing. Lactobacilli also as a member of LAB identified as GRAS and used as a commercial starter in fermented dairy products or as probiotics related to human health. They can play significant roles in different ways such as inhibition of pathogens, anti-cancer activity and different vitamins production in human. Given this point, this thesis has aimed to identify and select some new potential probiotic-technological strains of LAB which recently were isolated from different sources through genomic and physiological studies to be used in human health and food industry. All the strains were evaluated for different technological aspects such as acidification activity and fermentation on different sugars. The genomes of strains were sequenced and applied for in-silico analysis to get enough information about their safety and application in technology and human health. On the other side, the interesting strains from technological part were selected to be evaluated for different in-vitro probiotic properties such as antibiotic susceptibility, hemolytic activity, resistance to simulated gastrointestinal conditions, bile salts hydrolysis activity, different vitamins production, adhesion to HT-29 human epithelial cell and anti-cancer activity against colorectal cancer cells (HT-29). Based on results from in-vitro probiotic characterization, strains Lactobacillus paracasei DTA81 and S. thermophilus TH982 were chosen for in-vivo experiments using the laboratory mice. The results of this study revealed that strain L. paracasei DTA81 was found to possess in-vitro and in-vivo probiotic properties besides lowering the blood cholesterol and Light Density Lipid (LDL) as well as Fasting Blood Sugar (FBS). Lactobacillus paracasei DTA81 had already indicated interesting technological traits such as growing on all different sugars including some prebiotics as well

Whole-genome sequence and comparative genome analysis of Lactobacillus paracasei DTA93, a promising probiotic lactic acid bacterium

The complete genome sequence of Lactobacillus paracasei DTA93, isolated from healthy infant feces is reported, along with in silico genetic analyses of its main features. The 3.02\ua0Mb sequenced genome possesses 2990 protein-coding sequences distributed on 341 SEED subsystems. In previous in vitro studies, this strain demonstrated interesting probiotic properties, anti-cancer activity, and anti-bacterial activity. The whole-genome sequencing allowed to identify DTA93 as L. paracasei and to precisely place it within the L. casei group, since it shows the highest number of orthologous genes/proteins in common with the type strain L. paracasei ATCC 25302T. In silico analyses revealed the absence of potentially negative traits, such as presence of prophages, transmissible antibiotic resistance and virulence factors. The results provided here considerably increased the amount of information available on DTA93 in favor of its possible use in food products as health-promoting culture. The complete genome data have been deposited in GenBank under the accession number VTYT00000000

Identification and Transferability of Tetracycline Resistance in Streptococcus thermophilus during Milk Fermentation, Storage, and Gastrointestinal Transit

The existence of antibiotic-resistant bacteria in food products, particularly those carrying acquired resistance genes, has increased concerns about the transmission of these genes from beneficial microbes to human pathogens. In this study, we evaluated the antibiotic resistance-susceptibility patterns of 16 antibiotics in eight S. thermophilus strains, whose genome sequence is available, using phenotypic and genomic approaches. The minimal inhibitory concentration values collected revealed intermediate resistance to aminoglycosides, whereas susceptibility was detected for different classes of β-lactams, quinolones, glycopeptide, macrolides, and sulfonamides in all strains. A high tetracycline resistance level has been detected in strain M17PTZA496, whose genome analysis indicated the presence of the tet(S) gene and the multidrug and toxic compound extrusion (MATE) family efflux pump. Moreover, an in-depth genomic analysis revealed genomic islands and an integrative and mobilizable element (IME) in the proximity of the gene tet(S). However, despite the presence of a prophage, genomic islands, and IME, no horizontal gene transfer was detected to Lactobacillus delbrueckii subsp. lactis DSM 20355 and Lactobacillusrhamnosus GG during 24 h of skim milk fermentation, 2 weeks of refrigerated storage, and 4 h of simulated gastrointestinal transit