Instrumental Analysis of bacterial cells growth under incubation with Crocus sativus L. extracts using FT-IR spectroscopy

Foodborne illness is a threat to public health and challenge for food industry. Very young children, pregnant women, people with compromised immune systems and the elderly are at the most risk. Foodborne illness also known as food poisoning usually arises from improper handling, preparation, or food storage and is associated with microbial pathogens. Bacteria are a common cause of foodborne illness and especially Salmonella and Escherichia coli. At present food industry uses chemical additives in several processes in order to prevent bacterial growth and extend the shelf life of foods. However, these substances have adverse effects. In the current study, Crocus sativus L. extracts were tested as potential natural antimicrobial agents. The antimicrobial activity of plants extracts was studied towards Gram-negative strains belonging to the above species. Fourier transform infrared spectroscopy (FT-IR) was applied in order to evaluate the changes in the cellular composition of target bacterial cells after their exposure to extracts

Antimicrobial activity of plant extracts against oral pathogens. Detection of cellular structural changes by FT-IR.

Periodontal diseases and dental caries are common oral disorders in human population with a multifactorial etiology closely related with the development of dental plaque. The latter is composed of native oral microbiota and it is accumulated on teeth surfaces. Several antiseptic agents are used widely to inhibit bacterial growth [1,2]. However, these substances have adverse effects. In the current study, six plants extracts namely, chamomile, dittany, lemon balm, rosemary, saffron and sage, were tested as potential natural antimicrobial agents. The antimicrobial activity of plants extracts was studied towards Gram-positive strains belonging to Streptococcus species related to the oral health. Fourier transform infrared spectroscopy (FT-IR) was applied in order to evaluate the changes in the cellular composition of target bacterial cells after their exposure to extracts of both plants

Comparative study of biological activities of Crocus sativus L. extracts and Lamiaceae plants’ extracts

In the current study, different extracts of Origanum dictamnus L. leaves (dittany), Melissa officinalis L. leaves (lemon balm) and Crocus sativus L. stigmas (saffron) were tested as potential natural antoxidant and antimicrobial agents

Antimicrobial activity of Melissa officinalis L. and Crocus sativus L. against oral pathogens: Detection of cellular structural changes by FT-IR.

Periodontal diseases and dental caries are common oral disorders in human population with a multifactorial etiology closely related with the development of dental plaque. The latter is composed of native oral microbiota and it is accumulated on teeth surfaces. Several antiseptic agents are used widely to inhibit bacterial growth [1,2]. However, these substances have adverse effects. In the current study, Melissa officinalis L. and Crocus sativus L. extracts were tested as potential natural antimicrobial agents. The antimicrobial activity of plants extracts was studied towards Gram-positive strains belonging to Streptococcus species related to the oral health. Fourier transform infrared spectroscopy (FT-IR) was applied in order to evaluate the changes in the cellular composition of target bacterial cells after their exposure to extracts of both plants

A Key Role of Dendritic Cells in Probiotic Functionality

BACKGROUND: Disruption of the intestinal homeostasis and tolerance towards the resident microbiota is a major mechanism involved in the development of inflammatory bowel disease. While some bacteria are inducers of disease, others, known as probiotics, are able to reduce inflammation. Because dendritic cells (DCs) play a central role in regulating immune responses and in inducing tolerance, we investigated their role in the anti-inflammatory potential of probiotic lactic acid bacteria. METHODOLOGY/PRINCIPAL FINDINGS: Selected LAB strains, while efficiently taken up by DCs in vitro, induced a partial maturation of the cells. Transfer of probiotic-treated DCs conferred protection against 2, 4, 6-trinitrobenzenesulfonic acid (TNBS)-induced colitis. Protection was associated with a reduction of inflammatory scores and colonic expression of pro-inflammatory genes, while a high local expression of the immunoregulatory enzyme indolamine 2, 3 dioxgenase (IDO) was observed. The preventive effect of probiotic-pulsed DCs required not only MyD88-, TLR2- and NOD2-dependent signaling but also the induction of CD4+ CD25+ regulatory cells in an IL-10-independent pathway. CONCLUSIONS/SIGNIFICANCE: Altogether, these results suggest that selected probiotics can stimulate DC regulatory functions by targeting specific pattern-recognition receptors and pathways. The results not only emphasize the role of DCs in probiotic immune interactions, but indicate a possible role in immune-intervention therapy for IBD

RNA arbitrarily primed PCR and fourier transform infrared spectroscopy reveal plasticity in the acid tolerance response of Streptococcus macedonicus

We have previously reported that an acid tolerance response (ATR) can be induced in Streptococcus macedonicus cells at mid-log phase after autoacidification, transient exposure to acidic pH, or acid habituation, as well as at stationary phase. Here, we compared the transcriptional profiles of these epigenetic phenotypes, by RNA arbitrarily primed PCR (RAP-PCR), and their whole-cell chemical compositions, by Fourier transform infrared spectroscopy (FT-IR). RAP-PCR fingerprints revealed significant differences among the phenotypes, indicating that gene expression during the ATR is influenced not only by the growth phase but also by the treatments employed to induce the response. The genes coding for the mannose-specific IID component, the 1,2-diacylglycerol 3-glucosyltransferase, the 3-oxoacyl-acyl carrier protein, the large subunit of carbamoylphosphate synthase, and a hypothetical protein were found to be induced at least under some of the acid-adapting conditions. Furthermore, principal component analysis of the second-derivative-transformed FT-IR spectra segregated S. macedonicus phenotypes individually in all spectral regions that are characteristic for major cellular constituents like the polysaccharides of the cell wall, fatty acids of the cell membrane, proteins, and other compounds that absorb in these regions. These findings provide evidence for major changes in cellular composition due to acid adaptation that were clearly different to some extent among the phenotypes. Overall, our data demonstrate the plasticity in the ATR of S. macedonicus, which reflects the inherent ability of the bacterium to adjust the response to the distinctiveness of the imposed stress condition, probably to maximize its adaptability. Copyright © 2008, American Society for Microbiology. All Rights Reserved

Incidence of bacteriocins produced by food-related lactic acid bacteria active towards oral pathogens

In the present study we investigated the incidence of bacteriocins produced by 236 lactic acid bacteria (LAB) food isolates against pathogenic or opportunistic pathogenic oral bacteria. This set of LAB contained several strains (≥17%) producing bacteriocins active against food-related bacteria. Interestingly only Streptococcus macedonicus ACA-DC 198 was able to inhibit the growth of Streptococcus oralis, Streptococcus sanguinis and Streptococcus gordonii, while Lactobacillus fermentum ACA-DC 179 and Lactobacillus plantarun ACA-DC 269 produced bacteriocins solely against Streptococcus oralis. Thus, the percentage of strains that were found to produce bacteriocins against oral bacteria was ~1.3%. The rarity of bacteriocins active against oral LAB pathogens produced by food-related LAB was unexpected given their close phylogenetic relationship. Nevertheless, when tested in inhibition assays, the potency of the bacteriocin(s) of S. macedonicus ACA-DC 198 against the three oral streptococci was high. Fourier-transform infrared spectroscopy combined with principal component analysis revealed that exposure of the target cells to the antimicrobial compounds caused major alterations of key cellular constituents. Our findings indicate that bacteriocins produced by food-related LAB against oral LAB may be rare, but deserve further investigation since, when discovered, they can be effective antimicrobials. © 2013 by the authors; licensee MDPI, Basel, Switzerland

Antimicrobial potential of probiotic or potentially probiotic lactic acid bacteria, the first results of the international European research project PROPATH of the PROEUHEALTH cluster

The EU-funded PROPATH project addresses the important health issue of prevention of gastrointestinal disorders through probiotics and prebiotics. Seven European laboratories are co-operating in this project, which aims to isolate and characterize the relevant antimicrobial agents to combat Gram-negative bacteria including Helicobacter pylori and Salmonella enterica serovar Typhimurium. In this paper, the first results on the screening for probiotic or potentially probiotic lactobacilli that exhibit antimicrobial activity towards these Gram-negative pathogenic bacteria are presented. Spot-on-lawn assays, well-diffusion assays and time-kill studies were performed among the lactic acid bacteria strains that were either collected from fermented foods and faeces (breast-fed babies, infants and animals) or isolated from commercial products to investigate whether any of the collected strains were inhibiting growth of or were killing certain indicator bacteria. Strains inhibiting the gastrointestinal pathogens mentioned above were found. Evidence has been obtained that compounds different from organic acids are produced