Fecal microbiota profiles of growing pigs and their relation to growth performance.

The early gut microbiota composition is fundamentally important for piglet health, affecting long-term microbiome development and immunity. In this study, the gut microbiota of postparturient dams was compared with that of their offspring in three Finnish pig farms at three growth phases. The differences in fecal microbiota of three study development groups (Good, Poorly, and PrematureDeath) were analyzed at birth (initial exposure phase), weaning (transitional phase), and before slaughter (stable phase). Dam Lactobacillaceae abundance was lower than in piglets at birth. Limosilactobacillus reuteri and Lactobacillus amylovorus were dominantly expressed in dams and their offspring. Altogether 17 piglets (68%) were identified with Lactobacillaceae at the initial exposure phase, divided unevenly among the development groups: 85% of Good, 37.5% of Poorly, and 75% of PrematureDeath pigs. The development group Good was identified with the highest microbial diversity, whereas the development group PrematureDeath had the lowest diversity. After weaning, the abundance and versatility of Lactobacillaceae in piglets diminished, shifting towards the microbiome of the dam. In conclusion, the fecal microbiota of pigs tends to develop towards a similar alpha and beta diversity despite development group and rearing environment.

Production of Bioactive Substances to Alleviates Hangover and Ethanol-Induced Liver Damage through Fermentation of Oenanthe javanica Using Lactiplantibacillus plantarum.

The purpose of this study is to evaluate the effect of the bioconversion products of Oenanthe javanica extract fermented by Lactiplantibacillus plantarum (OEFL) on relieving hangovers and improving liver function. In addition, the bioactive substance of the OEFL, which alleviates hangover and ethanol-induced liver damage, was identified and its bioactive property was verified through in vivo experiments. In major substances analysis using high-performance liquid chromatography, OEFL produced 9.5-fold higher p-coumaric acid than the O. Javanica extract (OE). In addition, considering that quinic acid, which is not present in the OE, was produced in the OEFL it was confirmed that chlorogenic acid was decomposed into quinic acid by bioconversion. In the in vivo experiment using Sprague-Dawley rats, the OEFL and p-coumaric acid diets reduced blood ethanol, acetaldehyde, GPT, and ALP concentrations, increasing blood albumin concentrations compared to ethanol-administered groups, demonstrating that OEFL and p-coumaric acid, the main substance in the OEFL, improved ethanol-induced liver damage. Furthermore, the OEFL and its main bioactive substance, p-coumaric acid, alleviated liver fibrosis by downregulating TGF-ß, SMAD-2, SMAD-4, α-SMA, and upregulating MMP-1. Therefore, OEFL is expected to be used as a functional food or pharmaceutical material as it has been confirmed to effectively relieve hangovers, prevent liver damage, and delay liver fibrosis in ethanol-induced liver damages.

The impact of cell-free supernatants of Lactococcus lactis subsp. lactis strains on the tyramine formation of Lactobacillus and Lactiplantibacillus strains isolated from cheese and beer.

Tyramine is one of the most toxic biogenic amines and it is produced commonly by lactic acid bacteria in fermented food products. In present study, we investigated the influence of selected nisin-producing Lactococcus lactis subsp. lactis strains and their cell-free supernatants (CFSs) on tyramine production by four Lactobacillus and two Lactiplantibacillus strains isolated from cheese and beer. Firstly, we examined the antimicrobial effect of the CFSs from twelve Lactococcus strains against tested tyramine producers by agar-well diffusion assay. Six Lactococcus strains whose CFSs showed the highest antimicrobial effect on tyramine producers were further studied. Secondly, we investigated the influence of the selected six Lactococcus strains and their respective CFSs on tyramine production by tested Lactobacillus and Lactiplantibacillus strains in MRS broth supplemented with 2 g.L-1 of l-tyrosine. Tyramine production was monitored by HPLC-UV. The tyramine formation of all tested Lactobacillus and Lactiplantibacillus strains was not detected in the presence of Lc. lactis subsp. lactis CCDM 71 and CCDM 702, and their CFSs. Moreover, the remainder of the investigated Lactococcus strains (CCDM 670, CCDM 686, CCDM 689 and CCDM 731) and their CFSs decreased tyramine production significantly (P < 0.05) - even suppressing it completely in some cases - in four of the six tested tyramine producing strains.

Inhibition of a spoilage exopolysaccharide producer by bioprotective extracts from Lactobacillus acidophilus CRL641 and Latilactobacillus curvatus CRL705 in vacuum-packaged refrigerated meat discs.

The effect of bioprotective extracts (BEs) from Lactobacillus acidophilus CRL641 (BE-1) and Latilactobacillus curvatus CRL705 (BE-2) against the exopolysaccharide producer Latilactobacillus sakei CRL1407 in vacuum-packaged meat discs at 4 °C was evaluated. Lat. sakei CRL1407 was able to grow in control samples from 2.80 to 7.77 log CFU/g after 38 days. BE-1 and BE-2 reduced bacterial growth by 2.11 and 1.35 log CFU/g, respectively, but their combination led to a greater growth reduction (3.31 log CFU/g). The antimicrobial activity was detected in treated samples with BE-1 and BE-1 + BE-2 until day 16, while with BE-2 only at the initial time. The pH values remained constant in the discs treated with the BEs combination, whereas the greatest drop in pH was observed in control samples. The minor lipid oxidation without perceptible color changes was detected in the presence of BE-1 and BE-1 + BE-2. The combination of BEs as biocontrol agent plus conventional preservation barriers could extend the fresh meat shelf-life without quality loss.

A refined medium to enhance the antimicrobial activity of postbiotic produced by Lactiplantibacillus plantarum RS5.

Postbiotic RS5, produced by Lactiplantibacillus plantarum RS5, has been identified as a promising alternative feed supplement for various livestock. This study aimed to lower the production cost by enhancing the antimicrobial activity of the postbiotic RS5 by improving the culture density of L. plantarum RS5 and reducing the cost of growth medium. A combination of conventional and statistical-based approaches (Fractional Factorial Design and Central Composite Design of Response Surface Methodology) was employed to develop a refined medium for the enhancement of the antimicrobial activity of postbiotic RS5. A refined medium containing 20 g/L of glucose, 27.84 g/L of yeast extract, 5.75 g/L of sodium acetate, 1.12 g/L of Tween 80 and 0.05 g/L of manganese sulphate enhanced the antimicrobial activity of postbiotic RS5 by 108%. The cost of the production medium was reduced by 85% as compared to the commercially available de Man, Rogosa and Sharpe medium that is typically used for Lactobacillus cultivation. Hence, the refined medium has made the postbiotic RS5 more feasible and cost-effective to be adopted as a feed supplement for various livestock industries.

3-Hydroxypropionic acid contributes to the antibacterial activity of glycerol metabolism by the food microbe Limosilactobacillus reuteri.

Strains of Limosilactobacillus reuteri are used as starter and bioprotective cultures and contribute to the preservation of food through the production of fermentation metabolites lactic and acetic acid, and of the antimicrobial reuterin. Reuterin consists of acrolein and 3-hydroxypropionaldehyde (3-HPA), which can be further metabolized to 1,3-propanediol and 3-hydroxypropionic acid (3-HP). While reuterin has been the focus of many investigations, the contribution of 3-HP to the antimicrobial activity of food related reuterin-producers is unknown. We show that the antibacterial activity of 3-HP was stronger at pH 4.8 compared to pH 5.5 and 6.6. Gram-positive bacteria were in general more resistant against 3-HP and propionic acid than Gram-negative indicator strains including common food pathogens, while spoilage yeast and molds were not inhibited by ≤ 640 mM 3-HP. The presence of acrolein decreased the minimal inhibitory activity of 3-HP against E. coli indicating synergistic antibacterial activity. 3-HP was formed during the growth of the reuterin-producers, and by resting cells of L. reuteri DSM 20016. Taken together, this study shows that food-related reuterin producers strains synthesize a second antibacterial compound, which might be of relevance when strains are added as starter or bioprotective cultures to food products.

Bioprotective extracts from Lactobacillus acidophilus CRL641 and Latilactobacillus curvatus CRL705 inhibit a spoilage exopolysaccharide producer in a refrigerated meat system.

The effect of bioprotective extracts (BEs) from Latilactobacillus curvatus CRL705 and Lactobacillus acidophilus CRL641 against Latilactobacillus sakei CRL1407 was evaluated in a refrigerated meat model system under vacuum and aerobic conditions at 4 and 10 °C. As shown by culturing, the BE-1 from L. acidophilus completely inhibited the spoilage strain, while that from Lat. Curvatus CRL705 (BE-2) and its combination with BE-1 exerted a bacteriostatic effect. The antimicrobial activity and exopolysaccharide production correlated with the efficacy of inhibitory treatment while final pH decrease was higher in control samples. When flow cytometry was applied, a lack of correlation with plate counting was found; counts under the detection limit for BE-1 at 21 and 28 days at 4 and 10 °C represented between 64.15 and 73.70% of dead cells. Thus, the concurrence of lactic acid bacteria as biocontrol agents and the use of more accurate tools to prevent the growth of deteriorating species will contribute to the extension of fresh meat shelf-life without quality loss.

ß-glucan formation is a selective advantage for beer-spoiling Levilactobacillus brevis TMW 1.2112 during planktonic growth.

Some lactic acid bacteria (LAB) isolated from beer or wine produce capsular ß-glucans from UDP-glucose via the membrane-anchored glycosyltransferase GTF-2. This phenomenon is feared in breweries, because the viscosity of the affected liquids drastically increases due to the ß-glucan and concomitant pellicle formation of these LAB. Currently it is unknown if this type of polysaccharide formation provides any advantage for the producing LAB during the colonization of (ethanol-containing) liquids. We thus used the ß-glucan producer Levilactobacillus (L.) brevis TMW 1.2112 and its ß-glucan-deficient transposon mutant (Δ gtf-2), and compared their growth at different ethanol concentrations and their competitiveness during co-cultivation. No significant inhibition in growth and differences in acidification were observed for both strains up to ethanol concentrations of 8% (v/v). At 10 % ethanol, the ß-glucan forming wildtype increased its cell number and produced more acid in comparison to the mutant strain, which settled at the bottom of the fermentation tubes at any tested condition. At higher ethanol concentrations (12-18 % v/v) both strains failed to grow, while a higher viability of the wildtype strain was observed. After co-cultivation of both strains for up to 72 h in liquid nutrient medium (without ethanol), significantly more ropy wildtype colonies were detected, if the wildtype had been initially applied in similar cell counts or in excess. By contrast, the number of smooth mutant colonies was solely significantly higher after 24 h of growth, if the mutant strain had been initially inoculated in excess. These results indicate that the ß-glucan-mediated pellicle formation by L. brevis TMW 1.2112 is its dominant phenotype and a selective advantage during colonization of liquids.

Microencapsulation of probiotic lactobacilli with shellac as moisture barrier and to allow controlled release.

BACKGROUND: Rapid dissolution in digestive tract and moisture sorption during ambient storage are the two challenges of dry probiotic preparations. To solve these problems, microcapsules with shellac (LAC) addition containing Limosilactobacillus reuteri TMW 1.656 were designed in this work to provide a good moisture barrier and to provide controlled release in digestive tract, based on the hydrophobicity and acid-resistance of LAC. Four microcapsules were prepared using the method of emulsification/external gelation based on the crosslinking reaction between alginate or LAC with calcium ion, including alginate/sucrose (ALG), alginate/shellac/sucrose (ALG/LAC), alginate/whey protein isolate/sucrose (ALG/WPI) and alginate/whey protein isolate/shellac/sucrose (ALG/WPI/LAC). RESULTS: Measurements of physical properties showed that microcapsules with LAC addition (ALG/WPI/LAC and ALG/LAC) had larger particle size, much denser structure, lower hygroscopicity and slower solubilization in water, which agreed with the primary microcapsule design. Probiotic survivals in digestive juices followed the order of ALG/WPI/LAC ≥ ALG/WPI ≥ ALG/LAC > ALG. Probiotic stability after heating and ambient storage both exhibited the order of ALG/WPI/LAC > ALG/LAC ≈ ALG/WPI > ALG, which can be explained by the decreased hygroscopicity with adding LAC. CONCLUSION: LAC addition contributed to better probiotic survivals after freeze drying, simulated digestion, heating and ambient storage, and whey protein isolate (WPI) addition had a synergistic effect. Microcapsule hygroscopicity was closely related with probiotic survivals after heating and ambient storage, while microcapsule solubilization was closely related with probiotic survivals in simulated juices. Within our knowledge, this is the first report to improve probiotic stability during ambient storage based on LAC hydrophobicity. © 2020 Society of Chemical Industry.

Morphological and physiological changes in Lentilactobacillus hilgardii cells after cold plasma treatment.

Atmospheric cold plasma (ACP) inactivation of Lentilactobacillus hilgardii was investigated. Bacteria were exposed to ACP dielectric barrier discharge with helium and oxygen as working gases for 5, 10, and 15 min. The innovative approach in our work for evaluation of bacterial survival was the use in addition to the classical plate culture method also flow cytometry which allowed the cells to be sorted and revealed different physiological states after the plasma treatment. Results showed total inhibition of bacterial growth after 10-min of ACP exposure. However, the analysis of flow cytometry demonstrated the presence of 14.4% of active cells 77.5% of cells in the mid-active state and 8.1% of dead cells after 10 min. In addition, some of the cells in the mid-active state showed the ability to grow again on culture medium, thus confirming the hypothesis of induction of VBNC state in L .hilgardii cells by cold plasma. In turn, atomic force microscopy (AFM) which was used to study morphological changes in L. hilgardii after plasma treatment at particular physiological states (active, mid-active, dead), showed that the surface roughness of the mid-active cell (2.70 ± 0.75 nm) was similar to that of the control sample (2.04 ± 0.55 nm). The lack of considerable changes on the cell surface additionally explains the effective cell resuscitation. To the best of our knowledge, AFM was used for the first time in this work to analyze cells which have been sorted into subpopulations after cold plasma treatment and this is the first work indicating the induction of VBNC state in L. hilgardii cells after exposure to cold plasma.

Growth and survival characteristics of Paucilactobacillus wasatchensis WDCO4.

Understanding characteristics that permit survival and growth of Paucilactobacillus wasatchensis as part of the nonstarter microbiota of cheese is important for minimizing unwanted gas formation in cheese that can cause downgrading because of slits and cracks. The ability of Plb. wasatchensis WDC04 to survive pasteurization was studied by inoculating raw milk with 108 cfu/mL and measuring survival after processing through a high-temperature, short-time pasteurizer. Extent and rate of growth of Plb. wasatchensis WDC04 as a function of pH, salt concentration, and presence of various organic acids were studied using 48-well microplates in an automated spectrophotometer measuring optical density at 600 nm. Better growth in the 1-mL wells was obtained when a micro-anaerobic environment (similar to that which occurs in cheese) was created by enzymically removing the oxygen. Faster growth occurred around neutral pH (pH 6 to 8) than at pH 5 (cheese pH), whereas only marginal growth occurred at pH 4. Adding sodium chloride retarded growth of Plb. wasatchensis WDC04, but slow growth occurred even at salt concentrations up to 6%. At salt-in-moisture (S/M) concentrations found in cheese, the rate of growth at 3.5% S/M >4.5% S/M >5.5% S/M. Thus, low salt level in cheese is a risk factor for Plb. wasatchensis growth during cheese storage and unwanted slits and cracks. Some of the organic acids tested (propionic, formic, and citric) tended to suppress growth of Plb. wasatchensis WDC04 more than would be expected from their effect on pH. No survival of Plb. wasatchensis WDC04 after pasteurization was observed with the reduction in numbers being 8 logs or more. Even subpasteurization heating at 69°C for 15 s was sufficient to inactivate Plb. wasatchensis WDC04, so its presence as part of the nonstarter microbiota of cheese should be considered as a postpasteurization environmental contamination.

Inactivation kinetics of beer spoilage bacteria (Lactobacillus brevis, Lactobacillus casei, and Pediococcus damnosus) during acid washing of brewing yeast.

This work aimed to estimate the inactivation kinetic parameters of four potential beer spoilage bacteria (Lactobacillus brevis DSM 6235, Lactobacillus casei ATCC 334, Pediococcus damnosus DSM 20289 and Pediococcus damnosus ATCC 29358) inoculated in brewing yeast submitted to acid washing with purposes of yeast recycle. The experiments were conducted at 4 °C in solutions with pH 1.5, pH 2, and pH 3 adjusted employing 85% phosphoric acid. The acid washing treatment of brewing yeasts in the most common pH used (pH 2.0) demanded almost 50 min for the first decimal reduction (δ) of L. brevis DSM 6235. Sensible strains to acid washing such as P. damnosus DSM 20289 demanded almost 70 min for 4 log reductions to be achieved. On the other hand, pH reduction of the acid washing from 2.0 to 1.5 allowed 4 log reduction of L. brevis DSM 6235) to be obtained in less than 50 min, without ruining brewer's yeast viability. Acid washing in pH 1.5 is a viable method for the inactivation of bacterial contaminants of brewing yeasts. Recycling of brewing yeasts through this approach may contribute to a more sustainable and environmental-friendly industry.

Metagenomic insights into the changes in microbial community and antimicrobial resistance genes associated with different salt content of red pepper (Capsicum annuum L.) sauce.

Fermented red pepper (FRP) sauce has been eaten in worldwide for many years. The salt content and resident microbial community influences the quality of the FRP sauce and may confer health (e.g., probiotics) or harm (e.g., antibiotic resistance genes) to the consumers in some circumstances; however, the salt-mediated alteration of microbial community and antibiotic resistance genes are little known. In this study, a combination of whole genome sequencing and amplicon analysis was used to investigate the changes in microbial community and antimicrobial resistance genes in response to different salt content during red pepper fermentation. While the family Enterobacteriaceae dominated in high-salt (15-25%) samples, Lactobacillaceae quickly became the dominant population in place of Enterobacteriaceae after 24 days in 10% salt samples. Compared to 0.05 antibiotic resistance genes (ARGs) per cell number on average in 10% salt sample, 16.6 ARGs were present in high-salt samples, wherein the bacterial hosts were major assigned to Enterobacteriaceae including genera Enterobacter, Citrobacter, Escherichia, Salmonella and Klebsiella. Multidrug resistance genes were the predominant ARG type. Functional profiling showed that histidine kinase functions were of much higher abundance in high-salt samples and included several osmotic stress-related two-component systems that simultaneously encoded ARGs. These results give first metagenomic insights into the salt-mediated changes in microbial community composition and a broad view of associated antibiotic resistance genes in the process of food fermentation.

Effects of sialylated lactulose on the mouse intestinal microbiome using Illumina high-throughput sequencing.

Sialylated oligosaccharides are known to have beneficial effects, such as increasing the level of bifidobacteria, reducing the levels of blood endotoxin and blood ammonia, and enhancing the body's immune system. However, it is unknown whether sialylated lactuloses have modulatory effects on the intestinal microbiota. In this study, 60 healthy mice were randomly divided into six groups, namely, a normal control group, a lactulose group, a Kdn-α2,3-lactulose group, a Kdn-α2,6-lactulose group, a Neu5Ac-α2,3-lactulose group, and a Neu5Ac-α2,6-lactulose group. After 14 days of lactulose administration, the feces of three mice from each group were collected, and the intestinal microbiota were detected by Illumina MiSeq high-throughput sequencing targeting the V3-V4 region of the 16S rDNA gene. At the phylum level, the relative abundance of Firmicutes was increased in the sialylated lactulose groups, while the abundance of Bacteroidetes was decreased. At the family level, sialylated lactulose intervention decreased the relative abundance of Bacteroidales S24-7 group and Helicobacteraceae and enhanced the abundance of Lactobacillaceae, which reflects the modulatory effect of sialylated lactulose on intestinal microbiota. Diversity analysis indicated that the index of Chao was higher in the sialylated lactulose groups than in the normal control group, and the Shannon and Simpson diversity indices were higher in the Kdnα-2,6-lactulose group and the Neu5Ac-α2,3-lactulose group than in the normal control group. The results of the intestinal microbiota sample composition indicated that there were differences between the sialylated lactulose groups and the normal control group. Thus, sialylated lactulose could be used as a functional food component with potential therapeutic applications in manipulating intestinal microbiota to exert beneficial effects on the host's health.

Sexual Dimorphism in the Response to Broad-spectrum Antibiotics During T Cell-mediated Colitis.

BACKGROUND: Broad-spectrum antibiotics [Abx], including combination therapy with ciprofloxacin and metronidazole, are often prescribed during the treatment of inflammatory bowel disease [IBD] to alleviate symptoms, but with varying success. In this pilot study, we studied the effects of Abx on the course of experimental colitis, with a particular focus on sex as a determinant of the microbial and inflammatory responses. METHODS: The effects of Abx were tested on colonic inflammation and microbiome in male and female Rag-/- mice, using adoptive transfer of naïve T cells to induce colitis in a short-term [2-week] and long-term [9-week] study. RESULTS: We observed disparities between the sexes in both the response to adoptive T cell transfer and the effects of Abx. At baseline without Abx, female mice displayed a trend toward a more severe colitis than males. In both the short- and the long-term experiments, gut microbiota of some female mice exposed to Abx showed weak, delayed, or negligible shifts. Caecum weight was significantly lower in Abx-treated females. Abx exposure favoured a quick and persistent rise in Enterococcaceae exclusively in females. Males had higher relative abundance of Lactobacillaceae following Abx exposure relative to females. Abx-treated females trended toward higher colitis scores than Abx-treated males, and towards higher levels of IL-17A, NOS2, and IL-22. CONCLUSIONS: Although preliminary, our results suggest a differential response to both inflammation and Abx between male and female mice, The findings may be relevant to current practice and also as the basis for further studies on the differential gender effects during long-term antibiotic exposure in IBD.

Reduced-Particle-Size Wheat Bran Is Efficiently Colonized by a Lactic Acid-Producing Community and Reduces Levels of Enterobacteriaceae in the Cecal Microbiota of Broilers.

In the present study, we investigated whether reducing the particle size of wheat bran affects the colonizing microbial community using batch fermentations with cecal inocula from seven different chickens. We also investigated the effect of in-feed administration of regular wheat bran (WB; 1,690 µm) and wheat bran with reduced particle size (WB280; 280 µm) on the cecal microbial community composition of broilers. During batch fermentation, WB280 was colonized by a lactic acid-producing community (Bifidobacteriaceae and Lactobacillaceae) and by Lachnospiraceae that contain lactic acid-consuming butyric acid-producing species. The relative abundances of the Enterobacteriaceae decreased in the particle-associated communities for both WB and WB280 compared to that of the control. In addition, the community attached to wheat bran was enriched in xylan-degrading bacteria. When administered as a feed additive to broilers, WB280 significantly increased the richness of the cecal microbiota and the abundance of bacteria containing the butyryl-coenzyme A (CoA):acetate CoA-transferase gene, a key gene involved in bacterial butyrate production, while decreasing the abundances of Enterobacteriaceae family members in the ceca. Particle size reduction of wheat bran thus resulted in the colonization of the bran particles by a very specific lactic acid- and butyric acid-producing community and can be used to steer toward beneficial microbial shifts. This can potentially increase the resilience against pathogens and increase animal performance when the reduced-particle-size wheat bran is administered as a feed additive to broilers.IMPORTANCE Prebiotic dietary fibers are known to improve the gastrointestinal health of both humans and animals in many different ways. They can increase the bulking capacity, improve transit times, and, depending on the fiber, even stimulate the growth and activity of resident beneficial bacteria. Wheat bran is a readily available by-product of flour processing and is a highly concentrated source of (in)soluble dietary fiber. The intake of fiber-rich diets has been associated with increased Firmicutes and decreased Proteobacteria numbers. Here, we show that applying only 1% of a relatively simple substrate which was technically modified using relatively simple techniques reduces the concentration of Enterobacteriaceae This could imply that in future intervention studies, one should take the particle size of dietary fibers into account.

Prebiotic Potential and Chemical Composition of Seven Culinary Spice Extracts.

The objective of this study was to investigate prebiotic potential, chemical composition, and antioxidant capacity of spice extracts. Seven culinary spices including black pepper, cayenne pepper, cinnamon, ginger, Mediterranean oregano, rosemary, and turmeric were extracted with boiling water. Major chemical constituents were characterized by RP-HPLC-DAD method and antioxidant capacity was determined by measuring colorimetrically the extent to scavenge ABTS radical cations. Effects of spice extracts on the viability of 88 anaerobic and facultative isolates from intestinal microbiota were determined by using Brucella agar plates containing serial dilutions of extracts. A total of 14 phenolic compounds, a piperine, cinnamic acid, and cinnamaldehyde were identified and quantitated. Spice extracts exhibited high antioxidant capacity that correlated with the total amount of major chemicals. All spice extracts, with the exception of turmeric, enhanced the growth of Bifidobacterium spp. and Lactobacillus spp. All spices exhibited inhibitory activity against selected Ruminococcus species. Cinnamon, oregano, and rosemary were active against selected Fusobacterium strains and cinnamon, rosemary, and turmeric were active against selected Clostridium spp. Some spices displayed prebiotic-like activity by promoting the growth of beneficial bacteria and suppressing the growth of pathogenic bacteria, suggesting their potential role in the regulation of intestinal microbiota and the enhancement of gastrointestinal health. The identification and quantification of spice-specific phytochemicals provided insight into the potential influence of these chemicals on the gut microbial communities and activities. Future research on the connections between spice-induced changes in gut microbiota and host metabolism and disease preventive effect in animal models and humans is needed.

The Efficient Clade: Lactic Acid Bacteria for Industrial Chemical Production.

Lactic acid bacteria are well known to be beneficial for food production and, as probiotics, they are relevant for many aspects of health. However, their potential as cell factories for the chemical industry is only emerging. Many physiological traits of these microorganisms, evolved for optimal growth in their niche, are also valuable in an industrial context. Here, we illuminate these features and describe why the distinctive adaptation of lactic acid bacteria is particularly useful when developing a microbial process for chemical production from renewable resources. High carbon uptake rates with low biomass formation combined with strictly regulated simple metabolic pathways, leading to a limited number of metabolites, are among the key factors defining their success in both nature and industry.

Changes in Environmental Conditions Modify Infection Kinetics of Dairy Phages.

Latent period, burst time, and burst size, kinetic parameters of phage infection characteristic of a given phage/host system, have been measured for a wide variety of lactic acid bacteria. However, most studies to date were conducted in optimal growth conditions of host bacteria and did not consider variations due to changes in external factors. In this work, we determined the effect of temperature, pH, and starvation on kinetic parameters of phages infecting Lactobacillus paracasei, Lactobacillus plantarum, and Leuconostoc mesenteroides. For kinetics assessment, one-step growth curves were carried out in MRS broth at optimal conditions (control), lower temperature, pH 6.0 and 5.0 (MRS6 and MRS5, respectively), or in medium lacking carbon (MRSN) or nitrogen (MRSC) sources. Phage infection was progressively impaired as environmental conditions were modified from optimal. At lower temperature or pH, infection was delayed, as perceived by longer latent and burst times. Burst size, however, was lower, equal or higher than for controls, but this effect was highly dependent on the particular phage-host system studied. Phage infection was strongly inhibited in MRSC, but only mildly impaired in MRSN. Nevertheless, growth of all the bacterial strains tested was severely compromised by starvation, without significant differences between MRSC and MRSN, indicating that nitrogen compounds are specifically required for a successful phage infection, beyond their influence on bacterial growth.

Autochthonous lactic acid bacteria with probiotic aptitudes as starter cultures for fish-based products.

This study focused on the selection of lactic starters with probiotic properties for the production of fermented fish-products by the use of a multivariate approach (Cluster Analysis and Principal Component Analysis). Seventy-five isolates were recovered from fish intestinal microbiota and characterized by evaluating phenotypical, technological and probiotic traits; the most promising isolates were molecularly identified and then used into fish fermented sausage production. Namely, data from technological characterization were modelled through Growth Index and used as input to run a preliminary selection. Thus, 15 promising strains were selected and subjected to probiotic characterization; considering the results from probiotic tests, 3 promising strains were finally chosen (11, 68 and 69), identified as members of the genus Lactobacillus and used for the validation at laboratory level through the assessment of their performances for the production of fermented fish sausages. The results were promising as the use of the selected strains reduced the fermentation time (2 days) ensuring a good microbiological quality of the final product.