Biological activity of the non-microbial fraction of kefir: antagonism against intestinal pathogens

2017 ◽  
Vol 84 (3) ◽  
pp. 339-345 ◽  
Author(s):  
Carolina Iraporda ◽  
Mário Abatemarco Júnior ◽  
Elisabeth Neumann ◽  
Álvaro Cantini Nunes ◽  
Jacques R Nicoli ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Biological Activity ◽  
Cell Model ◽  
Acetic Acid Bacteria ◽  
Fermented Milk ◽  
In Vitro Assays ◽  
Intestinal Epithelial ◽  
Milk Fermentation ◽  
Intestinal Pathogens

Kefir is a fermented milk obtained by the activity of kefir grains which are composed of lactic and acetic acid bacteria, and yeasts. Many beneficial health effects have been associated with kefir consumption such as stimulation of the immune system and inhibition of pathogenic microorganisms. The biological activity of kefir may be attributed to the presence of a complex microbiota as well as the microbial metabolites that are released during fermentation. The aim of this work was to characterise the non-microbial fraction of kefir and to study its antagonism againstEscherichia coli,Salmonellaspp. andBacillus cereus.During milk fermentation there was a production of organic acids, mainly lactic and acetic acid, with a consequent decrease in pH and lactose content. The non-microbial fraction of kefir added to nutrient broth at concentrations above 75% v/v induced a complete inhibition of pathogenic growth that could be ascribed to the presence of un-dissociated lactic acid. In vitro assays using an intestinal epithelial cell model indicated that pre-incubation of cells with the non-microbial fraction of kefir did not modify the association/invasion ofSalmonellawhereas pre-incubation ofSalmonellawith this fraction under conditions that did not affect their viability significantly decreased the pathogen's ability to invade epithelial cells. Lactate exerted a protective effect againstSalmonellain a mouse model, demonstrating the relevance of metabolites present in the non-microbial fraction of kefir produced during milk fermentation.

scholarly journals Characterization of Plant Growth-Promoting Traits and Inoculation Effects on Triticum durum of Actinomycetes Isolates under Salt Stress Conditions

Soil Systems ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 26
Author(s):  
Rihab Djebaili ◽  
Marika Pellegrini ◽  
Massimiliano Rossi ◽  
Cinzia Forni ◽  
Maria Smati ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Salt Stress ◽  
Plant Growth ◽  
Durum Wheat ◽  
Growth And Development ◽  
Indole Acetic Acid ◽  
Greenhouse Experiment ◽  
Hydrocyanic Acid ◽  
In Vitro Assays

This study aimed to characterize the halotolerant capability, in vitro, of selected actinomycetes strains and to evaluate their competence in promoting halo stress tolerance in durum wheat in a greenhouse experiment. Fourteen isolates were tested for phosphate solubilization, indole acetic acid, hydrocyanic acid, and ammonia production under different salt concentrations (i.e., 0, 0.25, 0.5, 0.75, 1, 1.25, and 1.5 M NaCl). The presence of 1-aminocyclopropane-1-carboxylate deaminase activity was also investigated. Salinity tolerance was evaluated in durum wheat through plant growth and development parameters: shoot and root length, dry and ash-free dry weight, and the total chlorophyll content, as well as proline accumulation. In vitro assays have shown that the strains can solubilize inorganic phosphate and produce indole acetic acid, hydrocyanic acid, and ammonia under different salt concentrations. Most of the strains (86%) had 1-aminocyclopropane-1-carboxylate deaminase activity, with significant amounts of α-ketobutyric acid. In the greenhouse experiment, inoculation with actinomycetes strains improved the morpho-biochemical parameters of durum wheat plants, which also recorded significantly higher content of chlorophylls and proline than those uninoculated, both under normal and stressed conditions. Our results suggest that inoculation of halotolerant actinomycetes can mitigate the negative effects of salt stress and allow normal growth and development of durum wheat plants.

scholarly journals Kefiran Ekstraktının Bazı Bitki Patojeni Bakterilerine Karşı Antimikrobiyal Etkisinin Değerlendirilmesi

2020 ◽  
Vol 8 (4) ◽  
pp. 889-894
Author(s):  
Bilgin Taşkın
Keyword(s):  
Antibacterial Effect ◽  
Antimicrobial Effect ◽  
Acetic Acid Bacteria ◽  
Fermented Milk ◽  
Diffusion Method ◽  
Milk Product ◽  
Bacterial Strains ◽  
Private Households ◽  
Different Temperatures

Kefir; is a fermented milk product which is produced by granules containing a wide variety of microorganisms such as lactic acid bacteria, acetic acid bacteria and yeasts. It is traditionally consumed in many countries. It has been shown in many studies that the polysaccharide structure surrounding the granules which is composed mainly of kefiran molecule has antimicrobial effect against various pathogens as well as many health promoting effects. In this study, 24 h fermented kefir was used with two types of kefir granules for production of kefiran extract. One of them is being sold commercially and the other was collected from private households in a different region of Turkey. Kefiran extraction was carried out from matured kefir granules using three different temperatures, 80°C, 90°C and 100°C. Also, the protein contents of the extracted solutions were determined by Bradford method. Protein content of the extract solutions obtained were measured as 0.001 g/ml. The antibacterial effect of 0.05, 0.1, 1 and 2 mg of this extract against several plant pathogenic bacterial strains belonging to genus Pseudomonas, Xanthomonas, Erwinia ve Clavibacter was investigated in vitro for the first time. For this purpose, two methods, disc diffusion method and spreading method were used. The AN and SD kefir supernatants used as the positive controls in the experiments showed an average of 13-17 mm and 10-14 mm inhibition zones on the isolates, respectively, but the antibacterial effect of kefiran extracts was not observed.

scholarly journals Growth Inhibition of Cronobacter sakazakii in Experimentally Contaminated Powdered Infant Formula by Kefir Supernatant

2015 ◽  
Vol 78 (9) ◽  
pp. 1651-1655 ◽  
Author(s):  
DONG-HYEON KIM ◽  
JUNG-WHAN CHON ◽  
IL-BYEONG KANG ◽  
HYUNSOOK KIM ◽  
HONG-SEOK KIM ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Acetic Acid ◽  
Infant Formula ◽  
Acetic Acid Bacteria ◽  
Fermented Milk ◽  
Food Samples ◽  
Powdered Infant Formula ◽  
Cronobacter Sakazakii ◽  
Lactobacillus Kefiri ◽  
Culture Supernatants

Kefir is a type of fermented milk containing lactic and acetic acid bacteria and yeast. In this study, we evaluated the antimicrobial activity of kefir supernatant against Cronobacter sakazakii in powdered infant formula (PIF). In a spot-on-lawn test, the growth of 20 C. sakazakii strains, including 10 clinical and 10 food isolates, was completely inhibited in the presence of kefir supernatant. Significant differences in the diameters of inhibition zones were observed upon treatment with kefir compared with the results for Lactobacillus kefiri and Candida kefyr culture supernatants or solutions of lactic and acetic acid and ethyl alcohol in the agar well diffusion test (P < 0.05). The addition of 100 μl of kefir supernatant to 1 ml of nutrient broth completely inhibited the growth of C. sakazakii, as evaluated by spectrophotometry. The antimicrobial activity of kefir supernatant in experimentally contaminated PIF was also tested; we found no viable C. sakazakii cells remaining in PIF rehydrated with 30% kefir supernatant solution for 1 h, demonstrating that the antimicrobial activity of kefir supernatant against C. sakazakii could be applied in real food samples.

Evaluation of the Biological Activity of Panamanian Plants through a Series of In vitro Assays

Planta Medica ◽  
2011 ◽  
Vol 77 (05) ◽  
Author(s):  
Y Vasquez ◽  
SI Khan ◽  
MP Gupta ◽  
IA Khan
Keyword(s):  
Biological Activity ◽  
In Vitro Assays

scholarly journals Structure-Activity Relationship Analysis of Benzotriazine Analogues as HIV-1 Latency-Reversing Agents

2020 ◽  
Vol 64 (8) ◽  
Author(s):  
Eric S. Sorensen ◽  
Amanda B. Macedo ◽  
Rachel S. Resop ◽  
J. Natalie Howard ◽  
Racheal Nell ◽  
...  
Keyword(s):  
Biological Activity ◽  
Transcriptional Activation ◽  
Transcriptional Activity ◽  
Cell Model ◽  
Systematic Analysis ◽  
Immune Effector ◽  
Relationship Analysis ◽  
Latent Hiv

ABSTRACT “Shock and kill” therapeutic strategies toward HIV eradication are based on the transcriptional activation of latent HIV with a latency-reversing agent (LRA) and the consequent killing of the reactivated cell by either the cytopathic effect of HIV or an arm of the immune system. We have recently found several benzotriazole and benzotriazine analogues that have the ability to reactivate latent HIV by inhibiting signal transducer and activator of transcription 5 (STAT5) SUMOylation and promoting STAT5 binding to the HIV long terminal repeat and increasing its transcriptional activity. To understand the essential structural groups required for biological activity of these molecules, we performed a systematic analysis of >40 analogues. First, we characterized the essential motifs within these molecules that are required for their biological activity. Second, we identified three benzotriazine analogues with similar activity. We demonstrated that these three compounds are able to increase STAT5 phosphorylation and transcriptional activity. All active analogues reactivate latent HIV in a primary cell model of latency and enhance the ability of interleukin-15 to reactivate latent HIV in cells isolated from aviremic participants. Third, this family of compounds also promote immune effector functions in vitro in the absence of toxicity or global immune activation. Finally, initial studies in mice suggest lack of acute toxicity in vivo. A better understanding of the biological activity of these compounds will help in the design of improved LRAs that work via inhibition of STAT5 SUMOylation.

DUSP16 IS A NOVEL IBD GENE IMPLICATED IN THE REGULATION OF DIFFERENTIATION AND HOMEOSTASIS OF INTESTINAL EPITHELIAL CELLS

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S29-S30
Author(s):  
Jessy Ntunzwenimana ◽  
Azadeh Alikashani ◽  
Claudine Beauchamp ◽  
Jean Paquette ◽  
Gabrielle Boucher ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Map Kinases ◽  
Intestinal Epithelial Cells ◽  
Cell Model ◽  
Basolateral Membrane ◽  
Intestinal Lumen ◽  
Interleukin 17 ◽  
Intestinal Epithelial ◽  
Intestinal Pathogens ◽  
Ht 29

Abstract Inflammatory bowel disease (IBD) are chronic inflammatory diseases including Crohn’s disease (CD) and ulcerative colitis (UC). More than 200 genomic regions have been identified and validated (association values〈 5x10-8) to be associated with CD, UC or IBD. These regions may contain multiple genes and the current challenge lies in identifying the causal gene in each of these. To address this problem, we performed a functional genomic screen of 145 genes from validated IBD loci, in a relevant intestinal epithelial cell model (HT-29). The results of this transcriptome-based screening revealed that the candidate IBD gene DUSP16 (a dual specificity phosphatase targeting MAP kinases (MAPKs) phosphorylation) as well as the known IBD gene KSR1 (a scaffold protein regulating the spatiotemporal activation of the ERK) regulate the expression of genes involved in intestinal differentiation and homeostasis. They induce, among others, the expression of the PIGR gene that encodes the polymeric immunoglobulin receptor. PIGR plays a role in transporting dimeric IgA molecules from the basolateral membrane of epithelial cells to the intestinal lumen, via transcytosis, where they play an essential role in protecting the epithelium against intestinal pathogens. Our hypothesis is that DUSP16 and KSR1 modulate the activity of MAPKs in intestinal epithelial cells to induce PIGR expression, thus participating in the maintenance of homeostasis of the intestinal barrier. To better understand how DUSP16 modulates the expression of PIGR, we used an approach of over- expression (cDNA) and knockdown (shRNA) of DUSP16 in HT-29 cells. Our results confirmed that DUSP16 induction increases the expression of PIGR, whereas a knockdown of DUSP16 reduces the basal level of PIGR. Next we confirmed by Western Blot that the induction of DUSP16 was accompanied by a decrease in MAPK phosphorylation. The involvement of MAPKs was also confirmed through the use of chemical inhibitors specific for each MAPK, with inhibition of ERK and p38 showing the strongest induction of PIGR expression. We are currently analyzing known functional mutants of DUSP16 and KSR1 to determine their impact on MAPK activity and on PIGR expression. This work supports a role for PIGR in disease pathogenesis, adding to two recent studies that documented that patients suffering from UC accumulated somatic mutations in a group of genes regulating the expression of PIGR by Interleukin 17. The mutated genes, including PIGR, were positively selected in inflamed tissues, indicating the importance of the biological function occupied by this gene in the maintenance of homeostasis. In conclusion, our study successfully identified functional links between two genes from independent IBD loci, and suggests that these DUSP16 and KSR1 play a role in the process of epithelial transcytosis and the development of IBD.

scholarly journals oxyR, a LysR-Type Regulator Involved in Klebsiella pneumoniae Mucosal and Abiotic Colonization

2009 ◽  
Vol 77 (12) ◽  
pp. 5449-5457 ◽  
Author(s):  
Claire Hennequin ◽  
Christiane Forestier
Keyword(s):  
Gastrointestinal Tract ◽  
Klebsiella Pneumoniae ◽  
Biofilm Formation ◽  
Defense Mechanisms ◽  
In Vitro Assays ◽  
Intestinal Epithelial ◽  
Bacterial Transcription ◽  
Host Interaction

ABSTRACT Colonization of the gastrointestinal tract is the first event in Klebsiella pneumoniae nosocomial infections, followed by colonization of the bladder or respiratory tract or entry into the bloodstream. To survive in the host, bacteria must harbor specific traits and overcome multiple stresses. OxyR is a conserved bacterial transcription factor with a key role both in the upregulation of defense mechanisms against oxidative stress and in pathogenesis by enhancing biofilm formation, fimbrial expression, and mucosal colonization. A homolog of oxyR was detected in silico in the K. pneumoniae sequenced genome and amplified from the LM21 wild-type strain. To determine the role of oxyR in K. pneumoniae host-interaction processes, an oxyR isogenic mutant was constructed, and its behavior was assessed. At concentrations lower than 107 ml−1, oxyR-deficient organisms were easily killed by micromolar concentrations of H2O2 and exhibited typical aerobic phenotypes. The oxyR mutant was impaired in biofilm formation and types 1 and 3 fimbrial gene expression. In addition, the oxyR mutant was unable to colonize the murine gastrointestinal tract, and in vitro assays showed that it was defective in adhesion to Int-407 and HT-29 intestinal epithelial cells. The behavior of the oxyR mutant was also determined under hostile conditions, reproducing stresses encountered in the gastrointestinal environment: deletion of oxyR resulted in higher sensitivity to bile and acid stresses but not to osmotic stress. These results show the pleiotropic role of oxyR in K. pneumoniae gastrointestinal colonization.

scholarly journals Shortened derivatives from native antimicrobial peptide LyeTx I: In vitro and in vivo biological activity assessment

2020 ◽  
pp. 153537022096696
Author(s):  
Leonardo Lima Fuscaldi ◽  
Joaquim Teixeira de Avelar Júnior ◽  
Daniel Moreira dos Santos ◽  
Daiane Boff ◽  
Vívian Louise Soares de Oliveira ◽  
...  
Keyword(s):  
Biological Activity ◽  
Antimicrobial Peptide ◽  
Mammalian Cells ◽  
Antimicrobial Agents ◽  
Sodium Dodecyl ◽  
Alpha Helix ◽  
In Vitro Assays ◽  
Control Group

In the continuing search for novel antibiotics, antimicrobial peptides are promising molecules, due to different mechanisms of action compared to classic antibiotics and to their selectivity for interaction with microorganism cells rather than with mammalian cells. Previously, our research group has isolated the antimicrobial peptide LyeTx I from the venom of the spider Lycosa erythrognatha. Here, we proposed to synthesize three novel shortened derivatives from LyeTx I (LyeTx I mn; LyeTx I mnΔK; LyeTx I mnΔKAc) and to evaluate their toxicity and biological activity as potential antimicrobial agents. Peptides were synthetized by Fmoc strategy and circular dichroism analysis was performed, showing that the three novel shortened derivatives may present membranolytic activity, like the original LyeTx I, once they folded as an alpha helix in 2.2.2-trifluorethanol and sodium dodecyl sulfate. In vitro assays revealed that the shortened derivative LyeTx I mnΔK presents the best score between antimicrobial (↓ MIC) and hemolytic (↑ EC50) activities among the synthetized shortened derivatives, and LUHMES cell-based NeuriTox test showed that it is less neurotoxic than the original LyeTx I (EC50 [LyeTx I mnΔK] ⋙ EC50 [LyeTx I]). In vivo data, obtained in a mouse model of septic arthritis induced by Staphylococcus aureus, showed that LyeTx I mnΔK is able to reduce infection, as demonstrated by bacterial recovery assay (∼10-fold reduction) and scintigraphic imaging (less technetium-99m labeled-Ceftizoxime uptake by infectious site). Infection reduction led to inflammatory process and pain decreases, as shown by immune cells recruitment reduction and threshold nociception increment, when compared to positive control group. Therefore, among the three shortened peptide derivatives, LyeTx I mnΔK is the best candidate as antimicrobial agent, due to its smaller amino acid sequence and toxicity, and its greater biological activity.

Cellular Alterations Induced by Candida albicans RC Nosodes: an in vitro Study

2021 ◽  
Vol 11 (40) ◽  
pp. 209-210
Author(s):  
Fortune Homsani ◽  
Gleyce Moreno ◽  
Camila Siqueira ◽  
Juliana Grechi ◽  
André Luis Santos ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Cell Viability ◽  
Cell Model ◽  
Etiologic Agent ◽  
Yeast Cells ◽  
In Vitro Assays ◽  
Mitochondrial Activity ◽  
No Production ◽  
Cellular Alterations

Introduction: Candidiasis is an opportunist infection, caused by yeast of the genus Candida, which emerges as one of the main causes of systemic infections in hospitalized patients. Candida albicans is the most common causing agent of these infections. According to the Brazilian Homeopathic Pharmacopeia[1], nosodes are medicines compounded from chemically undefined biological products. Living nosodes are prepared using the etiologic agent of an illness in its infective form, were first developed by Brazilian physician Roberto Costa (RC). Roberto Costa’s research indicated that living nosodes present a higher capability to stimulate the host’s immunological system [2]. Aim: This study aims to evaluate cellular alterations induced in C. albicans yeasts and RAW 264-7 macrophages by Candida albicans RC. Methodology: To prepare Candida albicans RC, one part of C. albicans infective yeast suspension (108 cell/ml) was diluted in 9 parts of sterile distilled water and submitted to 100 mechanical succussions. This process was successively repeated to the potencies of 12x and 30x1. Water 30x was prepared by the same technique, as control. The cell viability of C. albicans previously treated with nosodes in both potencies and respective controls was evaluated using the samples at the concentration of 10% (V/V), in a volume of 1ml, distributed in 1-3 days. The viability of the yeast cells was analyzed by MTT (3-(4,5-dimetiltiazol-2-il)-2,5-difeniltetrazolic) (5mg/ml) assay [3] and by Propidium Iodide (PI) incorporation methods. Additionally, using macrophages RAW 264-7 as a cell model, Nitric Oxide (NO) production and cell viability were also evaluated. For this, the following protocol of cell treatment was employed: on each experimental day, RAW 264-7 cells were treated 4 times (4 stimuli) with RC nosode 30x at the concentration of 10% (V/V). Results: The nosodes (12x and 30x) did not present cytotoxic effects on macrophage cells (n=1), or on C. albicans yeasts (n=2), as detected by MTT and PI methods. Moreover, no statistically significant differences on NO production were detected among the experimental groups (n=6). Conclusion: Preliminary results of in vitro assays indicate that nosodes (12x and 30x) do not alter mitochondrial activity or cell viability of C. albicans. Similarly, treatment by RC nosodes does not seem to alter NO release and mitochondrial activity of RAW macrophages. New experiments are being performed to confirm these preliminary data.

Transport of thiamine in human intestine: mechanism and regulation in intestinal epithelial cell model Caco-2

1999 ◽  
Vol 277 (4) ◽  
pp. C645-C651 ◽  
Author(s):  
Hamid M. Said ◽  
Alvaro Ortiz ◽  
Chandira K. Kumar ◽  
Nabendu Chatterjee ◽  
Pradeep K. Dudeja ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Epithelial Cells ◽  
Protein Tyrosine Kinase ◽  
Intestinal Epithelial Cells ◽  
Cell Model ◽  
Transport Systems ◽  
Organic Cations ◽  
Maximal Velocity ◽  
Intestinal Epithelial

The present study examined the intestinal uptake of thiamine (vitamin B1) using the human-derived intestinal epithelial cells Caco-2 as an in vitro model system. Thiamine uptake was found to be 1) temperature and energy dependent and occurred with minimal metabolic alteration; 2) pH sensitive; 3) Na+independent; 4) saturable as a function of concentration with an apparent Michaelis-Menten constant of 3.18 ± 0.56 μM and maximal velocity of 13.37 ± 0.94 pmol ⋅ mg protein−1⋅ 3 min−1; 5) inhibited by the thiamine structural analogs amprolium and oxythiamine, but not by unrelated organic cations tetraethylammonium, N-methylnicotinamide, and choline; and 6) inhibited in a competitive manner by amiloride with an inhibition constant of 0.2 mM. The role of specific protein kinase-mediated pathways in the regulation of thiamine uptake by Caco-2 cells was also examined using specific modulators of these pathways. The results showed possible involvement of a Ca2+/calmodulin (CaM)-mediated pathway in the regulation of thiamine uptake. No role for protein kinase C- and protein tyrosine kinase-mediated pathways in the regulation of thiamine uptake was evident. These results demonstrate the involvement of a carrier-mediated system for thiamine uptake by Caco-2 intestinal epithelial cells. This system is Na+independent and is different from the transport systems of organic cations. Furthermore, a CaM-mediated pathway appears to play a role in regulating thiamine uptake in these cells.

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