1,721,266 research outputs found
Yogurt, living cultures, and gut health
No full textBacteria used to ferment milk to obtain yogurt belong to thermophilic, bile-sensitive species of lactic acid bacteria, which are not ideally suited for survival into the human gut. However, assessing the viability of these bacteria through the digestive tract may be relevant to evaluate their potential to deliver some beneficial effects for the well-being of the consumer. The well-known reduction in the symptoms caused by lactose maldigestion is not the only benefit provided by yogurt starter cultures; some additional effects will be reviewed here, with special attention paid to data that may suggest a strain-dependent effect, features that are not present with lactose hydrolysis
Million et al "Comparative meta-analysis of the effect of Lactobacillus species on weight gain in humans and animals." Letter to editors.
No full textCertain strains of Lactobacillus appear to have a reproducible effect on weight as a weight-gain effect in lean humans and animals or a weight-loss effect in overweight/obese humans and animals. These results are completely sufficient to capture the attention of the scientific community to assess the effect on the weight of Lactobacillus-containing probiotics sold for human consumption
FAO/WHO Guidelines on Probiotics 10 Years Later
No full textOctober 1 to 4, 2001, Cordoba, Argentina: on this date (and not in 2006, as incorrectly reported in several documents!)a group of experts convened that in that beautiful town for an Expert Consultation held jointly by the FAO and WHO to provide a scientific opinion on the matter of "probiotica". The FAO/WHO collaboration stemmed from a request made by the Argentinian Government to solve an international trade litigation on a powdered milk containing lactic acid bacteria defined as "probiotics"
Probiotics and Health Claims: Hurdles for New Applications?
No full textINTRODUCTION: The initial outcomes of regulation (EC) No. 1924/2006 are in some cases encouraging but in others of some concern to microbiologists, and there are now both new and old hurdles for the research community to consider in the future. The positive aspects of this evolution include the introduction of a regulatory framework within which research and development activities can operate more safely in order to generate new knowledge and products. The negative aspects are that the scenario is not yet fully developed and there is concern that excessive regulation could hinder innovative research. This chapter reviews some of the hurdles posed by the first EFSA opinions on probiotic claims and some perspectives for future basic and applied research and to overcome these hurdles are presented
Lactobacillus crispatus M247: azioni immuno - modulanti e interazioni molecolari con l' epitelio intestinale
No full textCon il primo lavoro è stato identificato un tratto fenotipico di un ceppo di L.crispatus associato alla capacità di persistere e colonizzare il colon dell’ospite e di modificarene la composizione microbica, tale L.crispatus M247 è in grado di modificare, nell’epitelio del colon, il livello di espressione dei TLR2 dei TLR4 sia in vitro che in vivo. Con il secondo studio si identifica un meccanismo antinfiammatorio, prima sconosciuto, indotto da un ceppo probiotico che coinvolge l’attivazione di PPAR-γ e fornisce una nuova visuale sui meccanismi molecolari coinvolti nel dialogo tra epitelio intestinale e microbiota simbionte.The colonic microbiota is a major modulator of the mucosal immune system; therefore, its manipulation through
supplementation with probiotics may significantly affect the host’s immune responses. Since different probiotics
seem to exert various effects in vivo, we tested the relevance of the autoaggregation phenotype on the intestinal
persistence of lactobacilli and their ability to modulate the host’s innate immune responses. After 14 days of diet
supplementation, the aggregating strain Lactobacillus crispatus M247 but not aggregation-deficient isogenic mutant
MU5 was recovered from the feces and colonic mucosa of mice. This observation was confirmed by strain-specific
PCR amplification and by Lactobacillus-specific denaturing gradient gel electrophoresis analysis. Indeed, L. crispatus
M247 increased Toll-like receptor 2 (TLR2) mRNA levels, while it reduced TLR4 mRNA and protein levels in
the colonic mucosa, whereas MU5 was ineffective. In colonic epithelial cells (CMT-93 cells) L. crispatus M247 but
not MU5 induced time-dependent extracellular signal-regulated kinase-1 (ERK1) tyrosine phosphorylation and
TLR modulation, which were abolished in the presence of PD98059 (an ERK1 inhibitor). To assess the functional
relevance of probiotic-induced TLR modulation, we determined the consequences of L. crispatus preexposure on
TLR4 (lipopolysaccharide [LPS]) and TLR2 [Pam3Cys-Ser-(Lys)4] ligand-mediated effects in intestinal epithelial
cells. Preexposure to L. crispatus M247 blunted LPS-induced interleukin-6 (IL-6) release and inhibition of CMT-93
migration over a wound edge, whereas it enhanced TLR2-mediated IL-10 up-regulation. In summary, the aggregation
phenotype is required for L. crispatus persistence in the colon and for modulation of TLR2/TLR4 expression
through an ERK-dependent pathway. We speculate that the aggregation phenotype in L. crispatus M247 is required
to temper epithelial cell responsiveness to bacterial endotoxins, which thus affects the evolution of intestinal
inflammatory processes. Accumulating evidence indicates
that the peroxisome proliferator activated receptor
(PPAR)- is a major player in maintaining intestinal
mucosa homeostasis, but whether PPAR- is
directly involved in probiotic-mediated effects and
the molecular events involved in its activation are not
known. Methods: We investigated the role of PPAR-
in the immunomodulatory effects of Lactobacillus
crispatus M247 on intestinal epithelial cells (IEC) and
the role of probiotic-derived H2O2 on PPAR- activity.
Results: L crispatus M247 supplementation in
mice significantly increased PPAR- levels and transcriptional
activity in the colonic mucosa. L crispatus
M247 induced PPAR- nuclear translocation and enhanced
transcriptional activity in epithelial (CMT-93)
cells, as demonstrated by the increased luciferase activity
of a PPAR- –responsive element, PPAR- –
responsive gene up-regulation, and reduced activity
of an nuclear factor- B–responsive element. Pharmacologic
PPAR- inhibition or silencing by small interfering
RNA cancelled the L crispatus M247–mediated
effects in CMT-93 cells. Because Lactobacillus
strains producing little H2O2 failed to activate
PPAR- , we investigated the role of L crispatus M247–
derived H2O2 in PPAR- activation. L crispatus M247
induced a transient rise in intracellular H2O2 and
PPAR- transcriptional activity was cancelled by
antioxidant or H2O2 scavenger. Toll-like receptor
(TLR)-2 was not required for PPAR- up-regulation
mediated by L crispatus M247 in mice, although the
protective effects of L crispatus M247 on dextran sodium
sulfate-induced colitis were less pronounced in
TLR-2 / mice. Conclusions: L crispatus M247 uses
H2O2 as a signal transducing molecule to induce
PPAR- activation in IEC, directly modulating epithelial
cell responsiveness to inflammatory stimuli
Mammomics in sus scrofa: uncovering adaptation underlylng mammary development during pregnancy and lactation
No full textLa comprensione dei geni che controllano la crescita, lo sviluppo, e il metabolismo della ghiandola mammaria suina può rivelare potenziali vie metaboliche o di segnale per migliorare l'efficienza di sintesi del latte. Un microarray suino costituito da 13.263 oligonucleotidi (mer 70) è stato utilizzato per lo studio del profilo di trascrizione del tessuto mammario da 4.5 scrofe a -34, -14, -4, 0, 7, 14, 21, e 28 giorni rispetto alla data del parto. ANOVA (FDR ≤ 0.10) ha individuato 2664 geni differenzialmente espressi (DEG) in relazione allo stato fisiologico. L’analisi dei network e delle vie metaboliche ha identificato come funzioni molecolari più affette dallo stato fisiologico: crescita e proliferazione cellulare (548 geni) cellule di segnale(612 geni).La qPCR rimane il metodo migliore per la misurazione dell’ abbondanza mRNA ad alta precisione e per la validazione di dati array. Essenziale per assicurare l'affidabilità della qPCR è la normalizzazione dei dati con l’utilizzo di geni di controllo interno (ICG). Un analisi sulla stabilità dei geni ha identificato, tra i 19 potenziali ICG, API5, VABP, e MRPL39 come i più stabili ICG nel tessuto mammario suini e ha inoltre stabilito che l'uso di tali 3 geni è il più appropriato per il calcolo di un fattore di normalizzazione. I risultati sottolineano l'importanza di una corretta validazione dei controlli interni per qPCR ed evidenziano le limitazioni di utilizzo dell’assenza dell’effetto tempo come unico criterio per la selezione di CIG.Elucidating genes controlling growth, development, and metabolism of swine mammary glands can reveal potential metabolic or signalling pathways that might help improve efficiency of milk synthesis. A swine microarray consisting of 13,263 oligonucleotides (70 mer) was used for transcript profiling of mammary tissue from 4-5 sows at -34, -14, -4, 0, 7, 14, 21, and 28 d relative to parturition. ANOVA (FDR ≤ 0.10) identified 2,664 differentially expressed genes (DEG) dueto physiological state. Gene network/pathway analysis revealed that cell growth and proliferation (548 genes) and cell signaling (612 genes) were among the most affected molecular functions due to physiological state in DEG. QPCR remains the chosen method for high-precision mRNA abundance analysis and for array data validation. Essential for reliability of qPCR data is normalization using appropriate internal control genes (ICG). Gene stability analysis identified , among 19 potential ICG, API5, VABP, and MRPL39 as the most stable ICG in porcine mammary tissue and indicated that the use of those 3 genes was most appropriate for calculating a normalization factor. Results underscore the importance of proper validation of internal controls for qPCR and highlight the limitations of using absence of time effects as the criteria for selection of appropriate ICG
Molecular Characterization of Antibiotic Resistant Genes in Streptococcus Thermophilus
No full textObiettivo di questo lavoro è stato valutare la diffusione di AR in differenti ceppi di S. thermophilus isolati tra il 1947 e il 2004 e provenienti da differenti ambienti, in modo da avere un chiaro andamento del fenomeno; questo è stato possibile analizzando un numero significativo di ceppi isolati in un periodo di tempo che va da prima dell'utilizzo degli antibiotici fino ai giorni nostri. L'espressione fenotipica è stata valutata con tre differenti metodi (microdiluizioni in brodo, E-test e Disk Diffusion), in accordo con gli standard NCCLS, per la determinazione delle MICs (Minimum Inhibitory Concentration, ovvero Concentrazioni Minime Inibenti). Per la valutazione genetica è stata impiegata la tecnica dei microarrays a DNA utilizzando oligonucleotidi da 50 e 60-mer, per un totale di 300, appartenenti a 10 diverse classi di antibiotici. La conferma dei risultati è stata ottenuta mediante PCR e sequenziamento. In 9 ceppi di S. thermophilus è stato possibile mettere in evidenza la presenza di almeno uno dei geni tetS ed ermB responsabili della resistenza agli antibiotici Tetraciclina e Eritromicina rispettivamente.The aim of the present work was to assess the AR diffusion in a total of 70 different strains of Streptococcus thermophilus, collected between 1950 and 2004 and from different environments; in this way we had the possibility to obtain a clear overview of the response of these bacteria to a large variety of antibiotics, having been able to analyze a significant number of different strains, originated from different areas and distributed over a wide time period, since before the use of antibiotics up to the present day. The phenotypic expression has been evaluated by using three different methods: microdilution, E-test and disk diffusion. The genetic analysis was performed using 50 and 60-mer oligonucleotides DNA based micro array for the identification of AR genes; the AR genes represented by the oligonucleotides on the micro array belong to: Aminoglycoside, Extended Spectrum ?-lactamase (ESBL), Chloramphenicol, Macrolide Lincosamides and Streptogramin (MLS) group, Sulfonamide, Tetracycline, Trimethoprim and Vancomycin.
tetS and ermB genes were found and sequenced in 4 out of the total of the S. thermophilus investigated. Furthermore we have wanted to establish the genetic location of above-mentioned genes and assess their transfer intra and inter species adopting the conjugation technique in plate
TECNICHE AVANZATE NELLA MESSA A PUNTO DI TECNOLOGIE TRANSGENICHE E NON NELLA SPECIE MURINA
No full textL’osteopetrosi autosomale recessiva (ARO) è un gruppo di malattie dovute a un difettoso funzionamento degli osteoclasti che preclude un rimodellamento osseo corretto. Nel 50% dei casi umani il difetto è dovuto ad una delezione nel gene Tcirg1. Il modello murino mutante oc/oc porta lo stesso difetto genetico e fenotipico umano. Nel lavoro di tesi si è dimostrato che gli epatociti fetali di 12.5 giorni di gestazione trapiantati in utero in feti mutati di 13.5 giorni di gestazione sono in grado di curare il fenotipo malato. Si è inoltre derivata una sottolinea di cellule staminali embrionali murine transgeniche per il costrutto plasmidico GOF18eGFP. Si vuole utilizzare la GFP sotto il controllo del promotore del gene Oct-4 come marcatore del livello di staminalità cellulare per microiniettare le ESC in blastocisti murine mutate oc/oc.Autosomal recessive osteopetrosis (ARO) is a group of genetic disorders due to defects that preclude normal function of osteoclasts. In half the cases, human ARO is due to mutations in the Tcirg1 gene. The oc/oc mutant mouse closely recapitulates human Tcirg1-dependent ARO. In ths work we demonstrate that in utero injection of allogenic fetal liver cells on 12.5 days into oc/oc fetuses at 13.5 day post coitum completely rescue the osteopetrotic phenotype. Moreover, an embryonic stem cells line transgenic for GOF18eGFP was produced. The goal is to use the GFP under the transcriptional control of the Oct-4 promoter as a marker of pluripotency of the ESC that are to microinject into oc/oc blastocysts
Messa a punto di tecniche molecolari per lo studio della microflora intestinale di soggetti in età pediatrica
No full textLa DGGE ha messo in evidenza le modificazioni indotte da un prebiotico sul genere Bacteroides mentre non ha evidenziato variazioni a carico dei bifidobatteri. Ha messo in risalto come, durante lo svezzamento, i generi batterici dominanti subiscano variazioni correlate alla variabilità individuale mentre, in soggetti affetti dal morbo di Crohn, sia la TGGE che la DGGE evidenziano i drastici cambiamenti prodotti dalla nutrizione enterale. La quantificazione mediante Real-time PCR non ha messo in risalto variazioni statisticamente significative per Bifidobacterium, Bacteroides e C. difficile tra i soggetti trattati e quelli non trattati con prebiotico. Per i soggetti in svezzamento Enterococcus, Bifidobacterium, C. perfringens, E. coli e i membri della famiglia delle Enterobacteriaceae non subiscono variazioni statisticamente significative.DGGE analysis put in evidence that prebiotic treatment induces modification of Bacteroides population while any modifications have not been underlined for Bifidobacterium. During weaning modifications of the dominant bacterial genera are correlated to the individual variability and not to dietary changes. TGGE and DGGE techniques also underlined important changes of the intestinal microflora composition due to the enterale nutrition. Quantification of the most important genera and species shows that Bifidobacterium, Bacteoides and C. difficile are not characterised by statistically significant modifications during prebiotic treatment. More over Enterococcus, Bifidobacterium, Enterobacteriaceae, E. coli and C. perfringens did not show any statistically significant changes during weaning
THE GENETICS OF LEAF RUST RESISTANCE IN THE MODEL GRASS BRACHYPODIUM DISTACHYON
No full textBrachypodium distachyon è stato recentemente proposto come pianta modello per le Triticeae che includono frumento e orzo. L’obbiettivo del presente studio è stato quello di identificare regioni genomiche associate con la resistenza quantitativa alla ruggine fogliare in Brachypodium. Le malattie causate dalle ruggini fogliari causano ingenti perdite in termini di produzione delle specie cerealicole. Una popolazione di 110 individui F2 è stata sviluppata incrociando due linee inbred di Brachypodium e una mappa di linkage di marcatori AFLP è stata create. La mappa di linkage consiste di 192 loci AFLP in dieci gruppi di linkage, e copre una lunghezza pari a 1,231 Kosambi cM. Allo scopo di identificare loci coinvolti nella resistenza quantitativa sulla mappa, i 110 individui F2 sono stati valutati per la loro reazione alla ruggine fogliare allo stadio di plantula e a quello adulto. Per confermare i risultati delle piante F2, le rispettive famiglie F3 sono state studiate per la loro resistenza alla ruggine fogliare in due esperimenti indipendenti. Due loci genomici sembrano essere maggiormente coinvolti nella resistenza.Brachypodium distachyon has been proposed as a model species for the tribe of the Triticeae, which includes wheat and barley. The objective of our study was to identify the genomic regions associated with quantitative resistance to leaf rust in Brachypodium. Leaf rust diseases cause significant reductions annually in yield of cereal crops worldwide. An F2 mapping population of 110 individuals was generated between two Brachypodium inbred lines and a AFLP-based linkage map was developed. The linkage map consists of 192 AFLP loci in ten linkage groups, and spans a total genetic length of 1,231 Kosambi cM. To locate quantitative resistance loci on the map, the 110 F2 plants were evaluated for their reaction to the leaf rust at both seedling and adult plant stages. To improve QTL identification, F2-derived F3 families were studied for resistance to leaf rust in two independent experiments. Two major genomic regions involved in resistance to leaf rust were detected
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