scholarly journals Enantioselective Regulation of Lactate Racemization by LarR in Lactobacillus plantarum

2014 ◽  
Vol 197 (1) ◽  
pp. 219-230 ◽  
Author(s):  
Benoît Desguin ◽  
Philippe Goffin ◽  
Nordine Bakouche ◽  
Aurélie Diman ◽  
Eric Viaene ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactobacillus Plantarum ◽  
Point Mutations ◽  
Racemic Mixture ◽  
Content Type ◽  
Sugar Fermentation ◽  
Gel Retardation ◽  
Positive Effect

Lactobacillus plantarumis a lactic acid bacterium that produces a racemic mixture ofl- andd-lactate from sugar fermentation. The interconversion of lactate isomers is performed by a lactate racemase (Lar) that is transcriptionally controlled by thel-/d-lactate ratio and maximally induced in the presence ofl-lactate. We previously reported that the Lar activity depends on the expression of two divergently oriented operons: (i) thelarABCDEoperon encodes the nickel-dependent lactate racemase (LarA), its maturases (LarBCE), and a lactic acid channel (LarD), and (ii) thelarR(MN)QOoperon encodes a transcriptional regulator (LarR) and a four-component ABC-type nickel transporter [Lar(MN), in which the M and N components are fused, LarQ, and LarO]. LarR is a novel regulator of the Crp-Fnr family (PrfA group). Here, the role of LarR was further characterizedin vivoandin vitro. We show that LarR is a positive regulator that is absolutely required for the expression of Lar activity. Using gel retardation experiments, we demonstrate that LarR binds to a 16-bp palindromic sequence (Lar box motif) that is present in thelarR-larAintergenic region. Mutations in the Lar box strongly affect LarR binding and completely abolish transcription from thelarApromoter (PlarA). Two half-Lar boxes located between the Lar box and the −35 box of PlarApromote LarR multimerization on DNA, and point mutations within one or both half-Lar boxes inhibit PlarAinduction byl-lactate. Gel retardation and footprinting experiments indicate thatl-lactate has a positive effect on the binding and multimerization of LarR, whiled-lactate antagonizes the positive effect ofl-lactate. A possible mechanism of LarR regulation by lactate enantiomers is proposed.

Protective effects of Lactobacillus plantarum strain P1 against toxicity of the environmental oestrogen di-n-butyl phthalate in rats

2020 ◽  
Vol 11 (8) ◽  
pp. 803-813
Author(s):  
X. Shi ◽  
C. Hu ◽  
S. Cai ◽  
X. Tao ◽  
Y. Zhou ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactobacillus Plantarum ◽  
Therapeutic Strategy ◽  
Male Rats ◽  
Protective Effects ◽  
Oral Gavage ◽  
Butyl Phthalate ◽  
Maize Oil

Phthalates are contaminants widely distributed in the food-chain, and they are considered as important environmental oestrogens in our lives. In the present study, eight strains of lactic acid bacteria were isolated for their ability to adsorb di-n-butyl-phthalate (DBP), and one of the strains, Lactobacillus plantarum strain P1, was selected for more detailed analyses of its phthalate adsorption capacity in vitro. This study also evaluated the in vivo protective effects of strain P1 against DBP toxicity in rats. Sixteen rats were divided into four groups, and animals received by oral gavage every other day for a period of one month saline with or without strain P1 at 2×1011 cfu/kg followed by maize oil with or without DBP (50 mg/kg). Strain P1 could adsorb more DBP than saline alone, and the concentration of mono-n-butyl phthalate in urine was decreased in animals receiving P1. Furthermore, oestrogenic effects of the different treatments were assessed through counting of sperm and observation of testis, and strain P1 could protect the sexual organs of male rats. Our results suggested that P1 is effective against phthalate toxicity due to its ability to adsorb DBP in vivo and could be considered as a new dietary therapeutic strategy against environmental phtalate toxicity.

scholarly journals Enantiomers of Nifurtimox Do Not Exhibit Stereoselective Anti-Trypanosoma cruzi Activity, Toxicity, or Pharmacokinetic Properties

2015 ◽  
Vol 59 (6) ◽  
pp. 3645-3647 ◽  
Author(s):  
Carolina B. Moraes ◽  
Karen L. White ◽  
Stéphanie Braillard ◽  
Catherine Perez ◽  
Junghyun Goo ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Murine Model ◽  
Therapeutic Benefit ◽  
Racemic Mixture ◽  
Content Type ◽  
Pharmacokinetic Properties

ABSTRACTWith the aim of improving the available drugs for the treatment of Chagas disease, individual enantiomers of nifurtimox were characterized. The results indicate that the enantiomers are equivalent in theirin vitroactivity against a panel ofTrypanosoma cruzistrains;in vivoefficacy in a murine model of Chagas disease;in vitrotoxicity and absorption, distribution, metabolism, and excretion characteristics; andin vivopharmacokinetic properties. There is unlikely to be any therapeutic benefit of an individual nifurtimox enantiomer over the racemic mixture.

scholarly journals Elevated Cell Wall Chitin in Candida albicans Confers Echinocandin ResistanceIn Vivo

2011 ◽  
Vol 56 (1) ◽  
pp. 208-217 ◽  
Author(s):  
Keunsook K. Lee ◽  
Donna M. MacCallum ◽  
Mette D. Jacobsen ◽  
Louise A. Walker ◽  
Frank C. Odds ◽  
...  
Keyword(s):  
Weight Loss ◽  
Cell Wall ◽  
Candida Albicans ◽  
Point Mutations ◽  
Low Frequency ◽  
Normal Cells ◽  
Content Type ◽  
Echinocandin Resistance

ABSTRACTCandida albicanscells with increased cell wall chitin have reduced echinocandin susceptibilityin vitro. The aim of this study was to investigate whetherC. albicanscells with elevated chitin levels have reduced echinocandin susceptibilityin vivo. BALB/c mice were infected withC. albicanscells with normal chitin levels and compared to mice infected with high-chitin cells. Caspofungin therapy was initiated at 24 h postinfection. Mice infected with chitin-normal cells were successfully treated with caspofungin, as indicated by reduced kidney fungal burdens, reduced weight loss, and decreasedC. albicansdensity in kidney lesions. In contrast, mice infected with high-chitinC. albicanscells were less susceptible to caspofungin, as they had higher kidney fungal burdens and greater weight loss during early infection. Cells recovered from mouse kidneys at 24 h postinfection with high-chitin cells had 1.6-fold higher chitin levels than cells from mice infected with chitin-normal cells and maintained a significantly reduced susceptibility to caspofungin when testedin vitro. At 48 h postinfection, caspofungin treatment induced a further increase in chitin content ofC. albicanscells harvested from kidneys compared to saline treatment. Some of the recovered clones had acquired, at a low frequency, a point mutation inFKS1resulting in a S645Y amino acid substitution, a mutation known to confer echinocandin resistance. This occurred even in cells that had not been exposed to caspofungin. Our results suggest that the efficacy of caspofungin againstC. albicanswas reducedin vivodue to either elevation of chitin levels in the cell wall or acquisition ofFKS1point mutations.

scholarly journals Activity of Praziquantel Enantiomers and Main Metabolites against Schistosoma mansoni

2014 ◽  
Vol 58 (9) ◽  
pp. 5466-5472 ◽  
Author(s):  
Isabel Meister ◽  
Katrin Ingram-Sieber ◽  
Noemi Cowan ◽  
Matthew Todd ◽  
Murray N. Robertson ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Significant Role ◽  
Worm Burden ◽  
Racemic Mixture ◽  
Content Type ◽  
Effector Molecule ◽  
Oral Doses ◽  
Newly Transformed Schistosomula

ABSTRACTA racemic mixture ofRandSenantiomers of praziquantel (PZQ) is currently the treatment of choice for schistosomiasis. Though theSenantiomer and the metabolites are presumed to contribute only a little to the activity of the drug, in-depth side-by-side studies are lacking. The aim of this study was to investigate thein vitroactivities of PZQ and its main metabolites, namely,R- andS-cis- andR- andS-trans-4′-hydroxypraziquantel, against adult worms and newly transformed schistosomula (NTS). Additionally, we explored thein vivoactivity and hepatic shift (i.e., the migration of the worms to the liver) produced by each PZQ enantiomer in mice. Fifty percent inhibitory concentrations ofR-PZQ,S-PZQ, andR-trans- andR-cis-4′-hydroxypraziquantel of 0.02, 5.85, 4.08, and 2.42 μg/ml, respectively, for adultS. mansoniwere determinedin vitro. S-trans- andS-cis-4′-hydroxypraziquantel were not active at 100 μg/ml. These results are consistent with microcalorimetry data and studies with NTS.In vivo, single 400-mg/kg oral doses ofR-PZQ andS-PZQ achieved worm burden reductions of 100 and 19%, respectively. Moreover, worms treatedin vivowithS-PZQ displayed an only transient hepatic shift and returned to the mesenteric veins within 24 h. Our data confirm thatR-PZQ is the main effector molecule, whileS-PZQ and the metabolites do not play a significant role in the antischistosomal properties of PZQ.

scholarly journals Unravelling the Reduction Pathway as an Alternative Metabolic Route to Hydroxycinnamate Decarboxylation in Lactobacillus plantarum

2018 ◽  
Vol 84 (15) ◽  
Author(s):  
Laura Santamaría ◽  
Inés Reverón ◽  
Félix López de Felipe ◽  
Blanca de las Rivas ◽  
Rosario Muñoz
Keyword(s):  
Lactic Acid ◽  
Lactobacillus Plantarum ◽  
Metabolic Response ◽  
Reductase Activity ◽  
Bacterial Species ◽  
Hydroxycinnamic Acids ◽  
Hydroxyl Group ◽  
Transcriptomic Response ◽  
Content Type

ABSTRACT Lactobacillus plantarum is the lactic acid bacterial species most frequently found in plant-food fermentations where hydroxycinnamic acids are abundant. L. plantarum efficiently decarboxylates these compounds and also reduces them, yielding substituted phenylpropionic acids. Although the reduction step is known to be induced by a hydroxycinnamic acid, the enzymatic machinery responsible for this reduction pathway has not been yet identified and characterized. A previous study on the transcriptomic response of L. plantarum to p-coumaric acid revealed a marked induction of two contiguous genes, lp_1424 and lp_1425, encoding putative reductases. In this work, the disruption of these genes abolished the hydroxycinnamate reductase activity of L. plantarum, supporting their involvement in such chemical activity. Functional in vitro studies revealed that Lp_1425 (HcrB) exhibits hydroxycinnamate reductase activity but was unstable in solution. In contrast, Lp_1424 (HcrA) was inactive but showed high stability. When the hcrAB genes were co-overexpressed, the formation of an active heterodimer (HcrAB) was observed. Since L. plantarum reductase activity was only observed on hydroxycinnamic acids (o-coumaric, m-coumaric, p-coumaric, caffeic, ferulic, and sinapic acids), the presence of a hydroxyl group substituent on the benzene ring appears to be required for activity. In addition, hydroxycinnamate reductase activity was not widely present among lactic acid bacteria, and it was associated with the presence of hcrAB genes. This study revealed that L. plantarum hydroxycinnamate reductase is a heterodimeric NADH-dependent coumarate reductase acting on a carbon-carbon double bond. IMPORTANCE Lactobacillus plantarum is a bacterial species frequently found in the fermentation of vegetables where hydroxycinnamic acids are present. The bacterial metabolism on these compounds during fermentation plays a fundamental role in the biological activity of hydroxycinnamates. L. plantarum strains exhibit an as yet unknown reducing activity, transforming hydroxycinnamates to substituted phenylpropionic acids, which possess higher antioxidant activity than their precursors. The protein machinery involved in hydroxycinnamate reduction, HcrAB, was genetically identified and characterized. The heterodimeric NADH-dependent coumarate reductase HcrAB described in this work provides new insights on the L. plantarum metabolic response to counteract the stressful conditions generated by food phenolics.

scholarly journals MSH2Gene Point Mutations Are Not Antifungal Resistance Markers inCandida glabrata

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
María Ángeles Bordallo-Cardona ◽  
Caroline Agnelli ◽  
Ana Gómez-Nuñez ◽  
Carlos Sánchez-Carrillo ◽  
Emilio Bouza ◽  
...  
Keyword(s):  
Point Mutations ◽  
Gene Mutations ◽  
Housekeeping Genes ◽  
Antifungal Resistance ◽  
Content Type ◽  
Fluconazole Resistant ◽  
Patient Prognosis ◽  
Antifungal Use

ABSTRACTThe high rates of antifungal resistance inCandida glabratamay be facilitated by the presence of alterations in theMSH2gene. We aimed to study the sequence of theMSH2gene in 124 invasiveC. glabrataisolates causing incident episodes of candidemia (n= 81), subsequent candidemia episodes (n= 9), endocarditis (n= 2), andin vitro-generated echinocandin-resistant isolates (n= 32) and assessed its relationship with genotypes, acquisition of antifungal resistancein vivoandin vitro, and patient prognosis. TheMSH2gene was sequenced, and isolates were genotyped using six microsatellite markers and multilocus sequence typing (MLST) based on six housekeeping genes. According to EUCAST, isolates causing candidemia (n= 90) were echinocandin susceptible, and four of them were fluconazole resistant (MIC ≥64 mg/liter). One isolate obtained from a heart valve was resistant to micafungin and anidulafungin (MICs, 2 mg/liter and 1 mg/liter, respectively).MSH2gene mutations were present in 44.4% of the incident isolates, the most common being V239L. The presence ofMSH2mutations was not correlated within vitroorin vivoantifungal resistance. Microsatellite and MLST revealed 27 genotypes and 17 sequence types, respectively. Fluconazole-resistant isolates were unrelated. MostMSH2mutations were found in cluster isolates; conversely, some mutations were found in more than one genotype. No clinical differences, including previous antifungal use, were found between patients infected by wild-typeMSH2gene isolates and isolates with any point mutation. The presence ofMSH2gene mutations inC. glabrataisolates causing candidemia is not correlated with specific genotypes, the promotion of antifungal resistance, or the clinical outcome.

scholarly journals In VivoandIn VitroAntimalarial Properties of Azithromycin-Chloroquine Combinations That Include the Resistance Reversal Agent Amlodipine

2011 ◽  
Vol 55 (7) ◽  
pp. 3115-3124 ◽  
Author(s):  
Marcus R. Pereira ◽  
Philipp P. Henrich ◽  
Amar bir Singh Sidhu ◽  
David Johnson ◽  
Joel Hardink ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Inhibitory Concentration ◽  
Similar Efficacy ◽  
Racemic Mixture ◽  
Combination Therapies ◽  
Reversal Agent ◽  
Content Type ◽  
Resistance Reversal

ABSTRACTEvidence of emergingPlasmodium falciparumresistance to artemisinin-based combination therapies, documented in western Cambodia, underscores the continuing need to identify new antimalarial combinations. Given recent reports of the resurgence of chloroquine-sensitiveP. falciparumparasites in Malawi, after the enforced and prolonged withdrawal of this drug, and indications of a possible synergistic interaction with the macrolide azithromycin, we sought to further characterize chloroquine-azithromycin combinations for theirin vitroandin vivoantimalarial properties.In vitro96-h susceptibility testing of chloroquine-azithromycin combinations showed mostly additive interactions against freshly culturedP. falciparumfield isolates obtained from Mali. Some evidence of synergy, however, was apparent at the fractional 90% inhibitory concentration level. Additionalin vitrotesting highlighted the resistance reversal properties of amlodipine for both chloroquine and quinine.In vivoexperiments, using the Peters 4-day suppressive test in aP. yoeliimouse model, revealed up to 99.9% suppression of parasitemia following treatment with chloroquine-azithromycin plus theRenantiomer of amlodipine. This enantiomer was chosen because it does not manifest the cardiac toxicities observed with the racemic mixture. Pharmacokinetic/pharmacodynamic analyses in this rodent model and subsequent extrapolation to a 65-kg adult led to the estimation that 1.8 g daily ofR-amlodipine would be required to achieve similar efficacy in humans, for whom this is likely an unsafe dose. While these data discount amlodipine as an additional partner for chloroquine-based combination therapy, our studies continue to support azithromycin as a safe and effective addition to antimalarial combination therapies.

scholarly journals Mycobacterium tuberculosis embBCodon 306 Mutations Confer Moderately Increased Resistance to Ethambutol In Vitro and In Vivo

2011 ◽  
Vol 55 (6) ◽  
pp. 2891-2896 ◽  
Author(s):  
Claudia Plinke ◽  
Kerstin Walter ◽  
Sahar Aly ◽  
Stefan Ehlers ◽  
Stefan Niemann
Keyword(s):  
Resistance Mechanism ◽  
Point Mutations ◽  
Fold Increase ◽  
Wild Type ◽  
Content Type ◽  
First Line Therapy ◽  
The One ◽  
The Impact

ABSTRACTEthambutol (EMB) is a major component of the first-line therapy of tuberculosis. Mutations in codon 306 ofembB(embB306) were suggested as a major resistance mechanism in clinical isolates. To directly analyze the impact of individualembB306 mutations on EMB resistance, we used allelic exchange experiments to generateembB306 mutants ofM. tuberculosisH37Rv. The level of EMB resistance conferred by particular mutations was measuredin vitroandin vivoafter EMB therapy by daily gavage in a mouse model of aerogenic tuberculosis. The wild-typeembB306 ATG codon was replaced byembB306 ATC, ATA, or GTG, respectively. All of the obtainedembB306 mutants exhibited a 2- to 4-fold increase in EMB MIC compared to the wild-type H37Rv.In vivo, the one selectedembB306 GTG mutant required a higher dose of ethambutol to restrict its growth in the lung compared to wild-type H37Rv. These experiments demonstrate thatembB306 point mutations enhance the EMB MICin vitroto a moderate, but significant extent, and reduce the efficacy of EMB treatment in the animal model. We propose that conventional EMB susceptibility testing, in combination withembB306 genotyping, may guide dose adjustment to avoid clinical treatment failure in these low-level resistant strains.

scholarly journals Bioluminescence Imaging Study of Spatial and Temporal Persistence of Lactobacillus plantarum and Lactococcus lactis in Living Mice

2012 ◽  
Vol 79 (4) ◽  
pp. 1086-1094 ◽  
Author(s):  
Catherine Daniel ◽  
Sabine Poiret ◽  
Véronique Dennin ◽  
Denise Boutillier ◽  
Bruno Pot
Keyword(s):  
Lactic Acid ◽  
Gastrointestinal Tract ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Plantarum ◽  
Lactococcus Lactis ◽  
Bioluminescence Imaging ◽  
Ex Vivo ◽  
Mammalian Host ◽  
Content Type

ABSTRACTLactic acid bacteria, especially lactobacilli, are common inhabitants of the gastrointestinal tract of mammals, for which they have received considerable attention due to their putative health-promoting properties. In this study, we describe the development and application of luciferase-expressingLactobacillus plantarumandLactococcus lactisstrains for noninvasivein vivomonitoring in the digestive tract of mice. We report for the first time the functionalin vitroexpression inLactobacillus plantarumNCIMB8826 and inLactococcus lactisMG1363 of the click beetle luciferase (CBluc), as well asGaussiaand bacterial luciferases, using a combination of vectors, promoters, and codon-optimized genes. We demonstrate that a CBluc construction is the best-performing luciferase system for the noninvasivein vivodetection of lactic acid bacteria after oral administration. The persistence and viability of both strains was studied by bioluminescence imaging in anesthetized mice and in mouse feces.In vivobioluminescence imaging confirmed that after a single or multiple oral administrations,L. lactishas shorter survival times in the mouse gastrointestinal tract thanL. plantarum, and it also revealed the precise gut compartments where both strains persisted. The application of luciferase-labeled bacteria has significant potential to allow thein vivoandex vivostudy of the interactions of lactic acid bacteria with their mammalian host.

The depressing (negative) effect of oestradiol benzoate on the in vitro secretion of LH and FSH by the pituitary gland of the LRH-pretreated long-term ovariectomized rat changes into the augmentative (positive) effect after discontinuation of the LRH-pretreatment

1985 ◽  
Vol 110 (3) ◽  
pp. 329-337 ◽  
Author(s):  
G. A. Schuiling ◽  
H. Moes ◽  
T. R. Koiter
Keyword(s):  
Depressing Effect ◽  
Ovx Rats ◽  
Gonadotrophin Secretion ◽  
Oestradiol Benzoate ◽  
Negative Effect ◽  
Positive Effect ◽  
Perifusion System

Abstract. The effect of pretreatment in vivo with oestradiol benzoate on in vitro secretion of LH and FSH was studied in long-term ovariectomized (OVX) rats both at the end of a 5-day continuous in vivo pretreatment with LRH and 4-days after cessation of such LRH pretreatment. Rats were on day 0 sc implanted with osmotic minipumps which released LRH at the rate of 250 ng/h. Control rats were implanted with a piece of silicone elastomer with the dimensions of a minipump. On days 2 and 4 the rats were injected with either 3 μg EB or with oil. On day 5 part of the rats were decapitated and the in vitro autonomous (i.e. non-LRH-stimulated) and 'supra-maximally' LRHstimulated release of LH and FSH was studied using a perifusion system. From other rats the minipumps were removed on day 5 and perifusion was performed on day 9. On the 5th day of the in vivo LRH pretreatment the pituitary LH/FSH stores were partially depleted; the pituitaries of the EB-treated rats more so than those of the oil-injected rats. EB alone had no significant effect on the content of the pituitary LH- and FSH stores. On day 9, i.e. 4 days after removal of the minipumps, the pituitary LH and FSH contents had increased in both the oil- and the EB injected rats, but had not yet recovered to control values. In rats not subjected to the 5-days pretreatment with LRH EB had a positive effect on the supra-maximally LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. EB had no effect on the non-stimulated secretion of FSH. After 5 days of in vivo pretreatment with LRH only, the in vitro non-stimulated and supra-maximally LRH-stimulated secretion of both LH and FSH were strongly impaired, the effect correlating well with the LRH-induced depletion of the pituitary LH/FSH stores. In such LRH-pretreated rats EB had on day 5 a negative effect on the (already depressed) LRH-stimulated secretion of LH (not on that of FSH). EB had no effect on the non-stimulated LH/FSH secretion. It could be demonstrated that the negative effect of the combined LRH/EB pretreatment was mainly due to the depressing effect of this treatment on the pituitary LH and FSH stores: the effect of oestradiol on the pituitary LRH-responsiveness (release as related to pituitary gonadotrophin content) remained positive. In LRH-pretreated rats, however, this positive effect of EB was smaller than in rats not pretreated with LRH. Four days after removal of the minipumps there was again a positive effect of EB on the LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. The positive effect of EB on the pituitary LRH-responsiveness was as strong as in rats which had not been exposed to exogenous LRH. The non-stimulated secretion of FSH was again not affected by EB. The results demonstrate that the effect of EB on the oestrogen-sensitive components of gonadotrophin secretion consists of two components: an effect on the pituitary LRH-responsiveness proper, and an effect on the pituitary LH/FSH stores. The magnitude of the effect of EB on the LRH-responsiveness is LRH dependent: it is very weak (almost zero) in LRH-pretreated rats, but strong in rats not exposed to LRH as well as in rats of which the LRH-pretreatment was stopped 4 days previously. Similarly, the effect of EB on the pituitary LH and FSH stores is LRH-dependent: in the absence of LRH, EB has no influence on the contents of these stores, but EB can potentiate the depleting effect of LRH on the LH/FSH-stores. Also this effect disappear after cessation of the LRH-pretreatment.

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