Gotowa bibliografia na temat „Lactobacillus”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Zobacz listy aktualnych artykułów, książek, rozpraw, streszczeń i innych źródeł naukowych na temat „Lactobacillus”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Artykuły w czasopismach na temat "Lactobacillus"
1
Chen, Chunfei, Leilei Yu, Fengwei Tian, Jianxin Zhao i Qixiao Zhai. "Identification of Novel Bile Salt-Tolerant Genes in Lactobacillus Using Comparative Genomics and Its Application in the Rapid Screening of Tolerant Strains". Microorganisms 10, nr 12 (30.11.2022): 2371. http://dx.doi.org/10.3390/microorganisms10122371.
Pełny tekst źródłaStreszczenie:
Under bile salt treatment, strains display significant differences in their tolerance ability, suggesting the existence of diverse resistance mechanisms in Lactobacillus; however, the genes involved in this protective process are not fully understood. In this study, novel target genes associated with bile salt tolerance in Lactobacillus were identified using comparative genomics for PCR detection and the rapid screening of tolerant strains. The bile salt tolerance of 107 lactobacilli isolated from different origins was assessed, and 26 strains with comparatively large differences were selected for further comparative genomic analysis. Tolerant strains had 112 specific genes that were enriched in the phosphotransferase system, the two-component system, carbohydrate metabolism, and the ATP-binding cassette transporter. Six genes from Lactobacillus were cloned into the inducible lactobacillal expression vector pSIP403. Overexpression in the host strain increased its tolerance ability by 11.86–18.08%. The novel genes identified here can be used as targets to design primers for the rapid screening of bile salt-tolerant lactobacilli. Altogether, these results deepen our understanding of bile salt tolerance mechanisms in Lactobacillus and provide a basis for further rapid assessments of tolerant strains.
2
Výrostková, Jana, Ivana Regecová, Mariana Kováčová, Slavomír Marcinčák, Eva Dudriková i Jana Maľová. "Antimicrobial Resistance of Lactobacillus johnsonii and Lactobacillus zeae in Raw Milk". Processes 8, nr 12 (10.12.2020): 1627. http://dx.doi.org/10.3390/pr8121627.
Pełny tekst źródłaStreszczenie:
Lactobacillus johnsonii and Lactobacillus zeae are among the lactobacilli with probiotic properties, which occur in sour milk products, cheeses, and to a lesser extent in raw milk. Recently, resistant strains have been detected in various species of lactobacilli. The aim of the study was to determine the incidence of resistant Lactobacillus johnsonii and Lactobacillus zeae strains in various types of raw milk. A total of 245 isolates were identified by matrix-assisted laser desorption/ionization mass spectrometry and polymerase chain reaction methods as Lactobacillus sp., of which 23 isolates of Lactobacillus johnsonii and 18 isolates of Lactobacillus zeae were confirmed. Determination of susceptibility to selected antibiotics was performed using the E-test and broth dilution method, where 7.3% of lactobacilli strains were evaluated as ampicillin-resistant, 14.7% of isolates as erythromycin-resistant, and 4.9% of isolates as clindamycin-resistant. The genus Lactobacillus johnsonii had the highest resistance to erythromycin (34.8%), similar to Lactobacillus zeae (33.3%). Of the 41 isolates, the presence of the gene was confirmed in five Lactobacillus johnsonii strains and in two strains of Lactobacillus zeae. The presence of resistant strains of Lactobacillus johnsonii and Lactobacillus zeae is a potential risk in terms of spreading antimicrobial resistance through the food chain.
3
Bilkova, A., H. Kinova Sepova, M. Bukovsky i L. Bezakova. "Antibacterial potential of lactobacilli isolated from a lamb". Veterinární Medicína 56, No. 7 (11.08.2011): 319–24. http://dx.doi.org/10.17221/1583-vetmed.
Pełny tekst źródłaStreszczenie:
The antimicrobial properties of three potential probiotic strains of lactobacilli isolated from a lamb (Lactobacillus murinus C, Lactobacillus mucosae D and Lactobacillus reuteri E) were studied using the streak line method and the agar well diffusion assay. The probiotic lactobacilli strains Lactobacillus rhamnosus ATCC 53103, Lactobacillus reuteri ATCC 55730, Lactobacillus reuteri ATCC 55845 and Lactobacillus plantarum DSM 9843 were used for comparison. Using the streak line method the inhibitory activity of lactobacilli products towards ten Gram-positive and Gram-negative potential pathogenic bacteria under different cultivation conditions (anaeorobic or microaerobic preincubation of lactobacilli for 24 h or 48 h) was tested. The strongest inhibitory activity was demonstrated by the Lactobacillus reuteri E strain. The most sensitive strains to the antimicrobial activity of lactobacilli were Yersinia enterocolitica clinical isolate (19.9 ± 6.8 mm) and Listeria monocytogenes ATCC 51774 (17.7 ± 6.0 mm) after microaerobic and anaerobic preincubation, respectively. Generally, microaerobic conditions and longer preincubation of lactobacilli resulted in stronger inhibition of target bacteria. The inhibitory activity of lactobacilli towards selected lactobacilli strains was also tested. Only low inhibition of growth was observed. In the agar well diffusion assay the inhibitory effect of natural and modified lactobacilli culture cell-free supernatants, obtained from MRS broth cultures, on Staphylococcus aureus ATCC 6538 growth was determined. Supernatants were modified by heat (10 min/60 °C; 60 min/100 °C) and protease treatment and neutralization of pH. Neutralization elicited the most significant impact on the activity of supernatants and resulted in total loss of activity. After all other modifications supernatants retained some residual activity. The highest inhibitory activity was observed for the cell-free supernatant produced by Lactobacillus mucosae D.
4
Bobcek, B., Ľ. Gajdosová, M. Kacániová, J. Lejková, L. Hleba i V. Kmeť. "Antibacterial susceptibility of lactobacilli isolated from pork meat of conventional breeding". Biotehnologija u stocarstvu 27, nr 3 (2011): 799–807. http://dx.doi.org/10.2298/bah1103799b.
Pełny tekst źródłaStreszczenie:
The aim of this study was monitoring of antibiotic resistance of Enterobacteriaceae genera isolated from musculus longissimus at thoracis and musculus semimembranosus of pork. The pigs was feeding in two groups (control and experimental wit selenium application). For the antibiotic susceptibility testing disk diffusion method was used. Lactobacillus species were tested against two antibiotics: ampiciline, tetracycline. For the detection and identification of lactobacilli we used MRS and Rogose agar. For identification of lactobacilli MALDI-TOF-MS were used. The higher resistance of isolated bacteria were found on ampicillin (29%) and on tetracycline (46%) in experimental group. The lower resistance of isolated bacteria were found on ampicillin (25%) and on tetracycline (35%) in control group. The most resistance bacteria of Lactobacillus genus was Lactobacillus plantarum in control and experimental group, too. From MLT and MSM pork meat Lactobacillus species Lactobacillus reuteri, L. crispatus, L.paracasei, L. farcimins and L curvatus and from non-lactobacilli Lactococcus lastis, Pediococcus pentosaceus were isolated (Table 2). The higher isolated species from lactobacilli genera was Lactobacillus paracasei in control group with 35.63 % and Lactobacillus reuteri in experimental group with 25.83%.
5
Kabir, SM Lutful, SM Mushfiqur Rahman, Sucharit Basu Neogi, Mohummad Muklesur Rahman i M. Shahidur Rahman Khan. "Isolation, identification, molecular characterization and screening of probiotic activities of Lactobacillus species from poultry sources at live bird markets in Mymensingh, Bangladesh". Asian-Australasian Journal of Bioscience and Biotechnology 1, nr 1 (30.04.2016): 54–65. http://dx.doi.org/10.3329/aajbb.v1i1.61531.
Pełny tekst źródłaStreszczenie:
A study was conducted to isolate and characterize Lactobacilli from the gastrointestinal (GI) tract of broiler chickens in different markets along with evaluation of probiotic ability and antibiotic sensitivity of Lactobacillus isolates during the period of July, 2014 to December, 2014. The caecum and cloacal contents of 100 broiler chickens from different markets were collected and cultured on Man Rogosa and Sharp (MRS) broth and agar. Lactobacilli were isolated and characterized by using phenotypic (cell morphology, Gram’s staining, physiological and biochemical tests which are specific for Lactobacillus genus) and genotypic methods (PCR and RAPD). The identified Lactobacilli species were screened for probiotic properties by in vitro tests like acid tolerance and bile tolerance. Total eighty two isolates were identified as Lactobacillus based on morphological, physiological and biochemical tests which are specific for Lactobacillus genus. All of the Lactobacillus isolates were further identified at species level as Lactobacillus acidophilus, Lactobacillus crispatus, Lactobacillus galinarum and other unclassified Lactobacillus species based on sugar fermentation tests. The prevalence of Lactobacillus crispatus, Lactobacillus acidophilus and Lactobacillus gallinarum species found in the chickens were 21.95%, 18.29% and 17.07% respectively. A total of 10 Lactobacillus isolates were amplified by using 16S rRNA gene-based universal primers. Furthermore, out of 10 Lactobacillus isolates 4 molecular patterns were detected and 6 Lactobacillus isolates were clonal by randomly amplified ploymorphic DNA (RAPD) method in this study. Out of 15 Lactobacillus isolates, 10 isolates demonstrated probiotic ability as determined by bile tolerance test and acid tolerance test. Moreover, the results of antibiotic sensitivity showed that all of the isolates tested were sensitive to tetracycline and gentamicin. However, most of the isolates tested were resistant to ampicillin and cefradine. Potential probiotic bacterial strains from poultry sources were identified as well as characterized in this study. Asian Australas. J. Biosci. Biotechnol. 2016, 1 (1), 54-65
6
Henri-Dubernet, Ségolène, Nathalie Desmasures i Micheline Guéguen. "Diversity and dynamics of lactobacilli populations during ripening of RDO Camembert cheese". Canadian Journal of Microbiology 54, nr 3 (marzec 2008): 218–28. http://dx.doi.org/10.1139/w07-137.
Pełny tekst źródłaStreszczenie:
The diversity and dynamics of Lactobacillus populations in traditional raw milk Camembert cheese were monitored throughout the manufacturing process in 3 dairies. Culture-dependent analysis was carried out on isolates grown on acidified de Man – Rogosa – Sharpe agar and Lactobacillus anaerobic de Man Rogosa Sharpe agar supplemented with vancomycin and bromocresol green media. The isolates were identified by polymerase chain reaction – temperature gradient gel electrophoresis (PCR–TGGE) and (or) species-specific PCR and (or) sequencing, and Lactobacillus paracasei and Lactobacillus plantarum isolates were characterized by pulsed field gel electrophoresis (PFGE). Milk and cheese were subjected to culture-independent analysis by PCR–TGGE. Presumed lactobacilli were detected by plate counts throughout the ripening process. However, molecular analysis of total DNA and DNA of isolates failed to detect Lactobacillus spp. in certain cases. The dominant species in the 3 dairies was L. paracasei. PFGE analysis revealed 21 different profiles among 39 L. paracasei isolates. Lactobacillus plantarum was the second most isolated species, but it occurred nearly exclusively in one dairy. The other species isolated were Lactobacillus parabuchneri , Lactobacillus fermentum , Lactobacillus acidophilus , Lactobacillus helveticus , a Lactobacillus psittaci/delbrueckii subsp. bulgaricus/gallinarum/crispatus group, Lactobacillus rhamnosus , Lactobacillus delbrueckii subsp. bulgaricus, L. delbrueckii subsp. lactis, Lactobacillus brevis , Lactobacillus kefiri , and Lactobacillus perolens. Lactobacilli diversity at the strain level was high. Dynamics varied among dairies, and each cheese exhibited a specific picture of species and strains.
7
Dong, Jie, Yun Sheng Jiang, Hai Yu, Wen Juan Zhang i Yu Feng Liu. "Study on Lactobacillus Isolation from Rabbit Meat Sausage and its Fermentation Property". Applied Mechanics and Materials 140 (listopad 2011): 431–40. http://dx.doi.org/10.4028/www.scientific.net/amm.140.431.
Pełny tekst źródłaStreszczenie:
Three lactobacilli (L26, L34 , L106) isolated from naturally fermented rabbit sausage in a traditional way are identified as lactobacillus plantarum, lactobacillus sake and lactobacillus fructosus. Further study of its fermentation property shows that three lactobacilli are effective in acid production, alkali resistant, nitrite resistant and bacteriostatic, and are antagonisticaction free, which can be used as combined rabbit meat starter.
8
Stojanov, Spase, Tina Vida Plavec, Julijana Kristl, Špela Zupančič i Aleš Berlec. "Engineering of Vaginal Lactobacilli to Express Fluorescent Proteins Enables the Analysis of Their Mixture in Nanofibers". International Journal of Molecular Sciences 22, nr 24 (20.12.2021): 13631. http://dx.doi.org/10.3390/ijms222413631.
Pełny tekst źródłaStreszczenie:
Lactobacilli are a promising natural tool against vaginal dysbiosis and infections. However, new local delivery systems and additional knowledge about their distribution and mechanism of action would contribute to the development of effective medicine. This will be facilitated by the introduction of the techniques for effective, inexpensive, and real-time tracking of these probiotics following their release. Here, we engineered three model vaginal lactobacilli (Lactobacillus crispatus ATCC 33820, Lactobacillus gasseri ATCC 33323, and Lactobacillus jensenii ATCC 25258) and a control Lactobacillus plantarum ATCC 8014 to express fluorescent proteins with different spectral properties, including infrared fluorescent protein (IRFP), green fluorescent protein (GFP), red fluorescent protein (mCherry), and blue fluorescent protein (mTagBFP2). The expression of these fluorescent proteins differed between the Lactobacillus species and enabled quantification and discrimination between lactobacilli, with the longer wavelength fluorescent proteins showing superior resolving power. Each Lactobacillus strain was labeled with an individual fluorescent protein and incorporated into poly (ethylene oxide) nanofibers using electrospinning, as confirmed by fluorescence and scanning electron microscopy. The lactobacilli retained their fluorescence in nanofibers, as well as after nanofiber dissolution. To summarize, vaginal lactobacilli were incorporated into electrospun nanofibers to provide a potential solid vaginal delivery system, and the fluorescent proteins were introduced to distinguish between them and allow their tracking in the future probiotic-delivery studies.
9
Haarman, Monique, i Jan Knol. "Quantitative Real-Time PCR Analysis of Fecal Lactobacillus Species in Infants Receiving a Prebiotic Infant Formula". Applied and Environmental Microbiology 72, nr 4 (kwiecień 2006): 2359–65. http://dx.doi.org/10.1128/aem.72.4.2359-2365.2006.
Pełny tekst źródłaStreszczenie:
ABSTRACT The developing intestinal microbiota of breast-fed infants is considered to play an important role in the priming of the infants' mucosal and systemic immunity. Generally, Bifidobacterium and Lactobacillus predominate the microbiota of breast-fed infants. In intervention trials it has been shown that lactobacilli can exert beneficial effects on, for example, diarrhea and atopy. However, the Lactobacillus species distribution in breast-fed or formula-fed infants has not yet been determined in great detail. For accurate enumeration of different lactobacilli, duplex 5′ nuclease assays, targeted on rRNA intergenic spacer regions, were developed for Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus delbrueckii, Lactobacillus fermentum, Lactobacillus paracasei, Lactobacillus plantarum, Lactobacillus reuteri, and Lactobacillus rhamnosus. The designed and validated assays were used to determine the amounts of different Lactobacillus species in fecal samples of infants receiving a standard formula (SF) or a standard formula supplemented with galacto- and fructo-oligosaccharides in a 9:1 ratio (OSF). A breast-fed group (BF) was studied in parallel as a reference. During the 6-week intervention period a significant increase was shown in total percentage of fecal lactobacilli in the BF group (0.8% ± 0.3% versus 4.1% ± 1.5%) and the OSF group (0.8% ± 0.3% versus 4.4% ± 1.4%). The Lactobacillus species distribution in the OSF group was comparable to breast-fed infants, with relatively high levels of L. acidophilus, L. paracasei, and L. casei. The SF-fed infants, on the other hand, contained more L. delbrueckii and less L. paracasei compared to breast-fed infants and OSF-fed infants. An infant milk formula containing a specific mixture of prebiotics is able to induce a microbiota that closely resembles the microbiota of BF infants.
10
Ghazaei, Ciamak. "Isolation and Characterization of Lactic Acid Bacteria From Milk and Their Effects on the Pathogenic Bacteria". Research in Molecular Medicine 8, nr 4 (26.10.2020): 189–200. http://dx.doi.org/10.32598/rmm.8.4.4.
Pełny tekst źródłaStreszczenie:
Background: Probiotics are “live microbial cells” that are beneficial for human and animal health. Lactobacilli are such a diverse group of bacteria with similar metabolic and physiological characteristics, and constitute important and beneficial gut microflora. During carbohydrate fermentation, lactobacilli produce lactic acid as an end product in metabolism. Hence, lactobacilli have high significance to be used as probiotics in the food industry, because of their acidifying properties. Also, lactobacilli are considered “safe”, owing to their ubiquitous presence in the food. Many researchers provided evidence for the presence of lactobacilli in milk sources. Thus, the present study aimed to isolate and characterize different lactobacilli strains from milk sources and analyze their “probiotic potential”. Materials and methods: Forty-one lactobacilli isolates were obtained from raw cow milk. Then, the strains were characterized by morphological identification and biochemical tests. Besides, probiotic potentials were evaluated with the bile tolerance test, antibiotic susceptibility test, and determining suitable pH for the optimal growth of lactobacilli. The lactobacilli isolates were also analyzed for their probiotic characteristics and the release of antimicrobial substances. Their antimicrobial activities against pathogenic strains were assessed by determining the minimum inhibitory concentration, with the help of agar diffusion methods. Results: From 50 milk samples, 41 lactobacilli isolates were obtained, out of which five lactobacilli strains were identified as Lactobacillus casei, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus acidophilus, and Lactobacillus lactis. Moreover, 35 isolates showed an inhibitory effect. These strains were able to survive and grow in 0.5% to 2.5% bile salt concentrations. Lactic acid bacteria were susceptible to antibiotics, and 35 isolates obtained from raw milk showed an inhibitory effect against pathogenic bacteria. The observed minimum inhibitory concentration ranged from 50 to 100 µL and varied between the different pathogens. Conclusion: Out of 41 Lactobacillus isolates obtained from cow milk samples, 35 were identified with probiotic characteristics. Hence, this study highlighted the novel probiotic bacteria and validated the antimicrobial properties of the Lactobacillus spp against pathogenic bacteria.
Rozprawy doktorskie na temat "Lactobacillus"
1
Jin, Su. "Physiological characteristics and applications of Lactobacillus pentosus strains in selected dairy products". AgroParisTech, 2010. http://pastel.archives-ouvertes.fr/docs/00/55/22/70/PDF/These_Su_JIN.pdf.
Pełny tekst źródłaStreszczenie:
Deux souches de Lactobacillus pentosus, Ind1 et Ind3, ont été isolées à partir de « Naigeda », un fromage traditionnel Chinois produit dans la région du Xinjiang. Les propriétés probiotiques de L. Pentosus étant peu connues, la présente étude a été conduite afin de déterminer si ces 2 souches, Ind1 et Ind3, sont susceptibles d’être utilisées comme probiotiques. Les propriétés physiologiques de L. Pentosus Ind1 et Ind3 ont fait l’objet d’essais in vitro afin de déterminer leur tolérance à l’environnement gastro-intestinal et leur adhérence à l’épithélium intestinal. Leurs propriétés de dégradation de 3 substances carcinogènes (phénol, p-crésol et indole ; concentrations comprises entre 50 et 150 µg/mL) ainsi que leur inhibition éventuelle par ces mêmes substances ont été étudiées. Les effets des 2 souches de L. Pentosus sur la microflore intestinale de souris, après administration orale de 109cfu/mL dans 0. 5mL de lait écrémé, ont été analysés. A cet effet, les populations de Lactobacilles, Bifidobactéries, Entérobacilles, Entérocoques et Clostridium perfringens, contenues dans les fèces des souris, avant, pendant et après leur alimentation en probiotiques, ont été considérées. Enfin, les capacités des 2 souches de L. Pentosus à produire de l’acide -amino butyrique ont été étudiées, et les conditions de milieu et de culture assurant la meilleure production définies. Les résultats montrent que les 2 souches de L. Pentosus, Ind1 et Ind3, présentent des taux de survie élevés : plus de 90 % en milieu acide et de 80% dans une solution de bile. Les aptitudes à l’adhérence sont souches dépendantes, avec pour Ind3 un potentiel similaire à celui de souches probiotiques reconnues (NCFM et Lp115). Ind1 et Ind3 ont également montré une bonne résistance aux substances carcinogènes (phénol, p-crésol, indole à 150 μg/mL). Enfin, ces 2 souches permettent un accroissement des concentrations de Lactobacilles et de bifidobactéries, dans le tractus intestinal des souris, tout en inhibant la croissance des Entérobacilles et de C. Perfringens. Ces résultats démontrent les aptitudes potentielles des deux souches de L. Pentosus étudiées pour une utilisation comme souches probiotiques au sein de régimes diététiques ou pour l’élaboration de produits laitiers fermentésTwo Lactobacillus pentosus strains, Ind1 and Ind3, were isolated from a traditional Chinese cheese product called Naigeda, collected from Xinjiang region of China. Since there is little information regarding the probiotic properties of L. Pentosus strains, this study was designed to provide more supporting data for L. Pentosus as a potential probiotic strain application. The physiological properties of the two L. Pentosus strains, Ind1 and Ind3, such as the in vitro test on the intolerance under the gastro-intestinal environment, the ability of adherence on the intestinal epithelium were studied. Their intolerance as well as inhibition and degradation ability under presence of pre-carcinogenic substances existing in human gut such as phenol, p-cresol and indole at different concentrations were also determined. The effects of the two L. Pentosus strains on modulation of the mice intestinal micro flora, by oral administration of 109cfu/ml of strains in 0. 5ml of skim milk, were investigated: the amounts of Lactobacillus spp. , Bifidobacterium spp. , Enterobacilli, Enterococcus and Clostridium perfringens in the feces of mice during and after the feeding of probiotic strains were counted. Furthermore, the technological properties of the two L. Pentosus strains on their GABA producing ability were studied: the medium and process parameters optimization was carried out in order to try to obtain the highest GABA content in the fermented dairy products. Results showed that the two L. Pentosus strains had high survival rates (higher than 90% in acid and 80% in bile solution). The adhesive ability is strain independent: Ind3 adherence was comparable with those of two commercial probiotic strains (NCFM and Lp115). Ind1 and Ind3 showed good resistance mutagenic substances phenol, p-cresol, indole at concentration below 150 μg/mL). Ind1 and Ind3 also showed certain effect on promoting the increase of Lactobacillus and Bifidobacteria counts, and inhibiting the growth of Enterobacilli and Clostridium in mice gut. These results displayed positive properties that the two L. Pentosus strains can be good candidates to be used as probiotic strains potentially used in dietary supplement application or Chinese-style dairy products
2
Harris, Lyle Keenan. "Comparison of plasmids from clinical Lactobacillus strains". University of the Western Cape, 2018. http://hdl.handle.net/11394/6439.
Pełny tekst źródłaStreszczenie:
Magister Scientiae - MSc (Biotechnology)The vaginal mucosa is dominated by Gram positive, rod shaped lactobacilli which serve as a natural barrier against infection. In both healthy and BV infected women Lactobacillus crispatus and Lactobacillus jensennii has been found to be the predominant Lactobacillus species. Many studies have been conducted to assess factors influencing lactobacilli dominance in the vaginal microbiome. However, no study has evaluated the impact of plasmids on the vaginal lactobacilli. In the present study two plasmids, pLc17 and pLc4, isolated from vaginal Lactobacillus species of both healthy and BV infected women were characterized. pLc4 was present in both Lactobacillus crispatus and Lactobacillus jensennii while pLc17 was only present in Lactobacillus crispatus. pLc17 (16663 bp in size) encoded a ribonucleotide diphosphate reductase (RNR), a filamentation induced by cAMP-like (FIC-like) protein and numerous mobile elements.
3
Regulski, Krzysztof. "Influence of peptidoglycan metabolism on immunomodulatory properties of Lactobacillus casei". Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112313.
Pełny tekst źródłaStreszczenie:
Le peptidoglycane (PG) est le composant majeur de la paroi des bactéries à Gram positif. Il assure la forme et l’intégrité de la cellule bactérienne. Le PG ou des fragments dérivés sont connus pour être des inducteurs du système d’immunité innée de l’hôte, en particulier au travers des récepteurs Nod2. Au cours de ce travail, nous avons étudié l’influence du métabolisme du PG sur les propriétés immunomodulatrices de Lactobacillus casei BL23, en étudiant principalement sa capacité à moduler la réponse des cellules dendritiques humaines. Nous avons tout d’abord caractérisé les hydrolases du PG (PGHs) majeures de L. casei BL23. Une recherche in silico a révélé que L. casei possède un système de PGHs relativement complexe comprenant treize enzymes putatives avec des domaines catalytiques variés. Une analyse protéomique d’extraits de paroi de L. casei BL23 a permis de détecter la production de sept d’entre elles pendant la croissance bactérienne. Quatre d’entre elles ont été étudié plus en détails. La PGH la plus fortement exprimée, Lc-p75, a une activité de -D-glutamyl-L-lysyl-endopeptidase et est responsable de la séparation des cellules après division. De plus, Lc-p75 associée à la paroi est localisée au niveau des septa cellulaires. Il s’agit également de l’une des protéines majeures secrétée dans le surnageant de culture de L. casei BL23. Lc-p75 possède la particularité d’être une glycoprotéine. La PGH Lc-p40 possède un domaine CHAP doué d’une activité endopeptidase avec un site de clivage situé au niveau des ponts interpeptidiques du PG. Lc-p40 parait localisée au niveau de la paroi latérale des cellules de L. casei. Lc-p45 est une deuxième -D-glutamyl-L-lysyl-endopeptidase avec un rôle dans le maintien de la forme de la bactérie. Enfin nous avons caractérisé deux enzymes de prophages, Lc-Lys et Lc-Lys2, codée par le génome de L. casei BL23, qui possède toute deux un domaine de liaison au PG d’un nouveau type qui possède la particularité de lier spécifiquement le D-Asp amidé présent dans les ponts interpeptidiques du PG de L. casei BL23. La délétion des deux gènes qui codent pour les endopeptidases Lc-p75 et Lc-p45 chez L. casei BL23 conduit à l’absence de disaccharide dipeptide dans la structure du PG du mutant, tandis que la délétion de Lc-p75 seulement conduit à une réduction de la quantité du disaccharide-dipeptide. Ce disaccharide dipeptide est un ligand des récepteurs Nod2. Les deux mutants obtenus par délétion de Lc-p75 ou bien par délétion des deux endopeptidases ont été comparés avec la souche sauvage BL23 pour leur capacité à activer in vitro des cellules dendritiques humaines dérivées de monocytes sanguins. Suite à l’activation des cellules dendritiques par les souches de L. casei, quatre cytokines pro-inflammatoires, les interleukines IL-6, IL-8, IL-12 et le TNF- ont été produites. La quantité de chaque cytokine sécrétée en réponse aux mutants simple Lc-p75 et double Lc-p75/Lc-p45 était diminuée par rapport à celle induite par la souche sauvage L. casei BL23.En conclusion, L. casei BL23 est doté d’un équipement complexe en PGHs. Les PGHs caractérisées au cours de ce travail présentent des caractéristiques uniques et jouent un rôle important dans la division des bactéries ainsi que dans le maintien de leur morphologie. Nos résultats indiquent que la souche sauvage de L. casei Bl23 et les mutants dérivés obtenus par inactivation d’enzymes à activité endopeptidase, qui diffèrent à la fois au niveau de leur contenu enzymatique ainsi qu’au niveau de la structure de leur PG, ont des effets différents sur les cellules dendritiques humaines, avec un caractère anti-inflammatoire plus élevé pour les mutantsPeptidoglycan (PG) is the major component of the Gram-positive bacteria cell wall. It ensures bacterial cell shape and integrity. PG or PG-derived fragments have been shown to stimulate the host innate immune system, through Nod-2 receptors. In this work, we studied the influence of PG metabolism on immunomodulatory properties of Lactobacillus casei BL23, mainly its ability to modulate the response of human dendritic cells (DCs).We have first characterized the main peptidoglycan hydrolases (PGHs) of L. casei BL23. In silico search revealed that L. casei BL23 has a rather complex PGH complement including thirteen predicted PGHs with various catalytic domains. Proteomic analysis of bacterial cell wall extracts revealed the expression of seven of them during bacterial growth. We characterized four of them in details. Lc-p75 is the major PGH with a γ-D-glutamyl-L-lysyl-endopeptidase specificity and is responsible for daughter cell separation. Lc-p75 associated to the cell wall localizes at the cell septa. It is also one of the major secreted proteins of L. casei found in culture supernatant. Besides, we showed that L. casei Lc-p75 is a glycosylated protein. Lc-p40 is a PGH with a CHAP-domain endowed with endopeptidase hydrolytic specificity toward peptidoglycan cross-bridges and appears to localize on lateral cell wall. Lc-p45 is a second γ-D-glutamyl-L-lysyl endopeptidase with a role in cell shape maintenance. We further demonstrated that two prophage endolysins Lc-Lys and Lc-Lys2, encoded in L. casei BL23 genome, share a common novel type peptidoglycan-binding domain that recognizes specifically D-Asn cross-bridge, present in L. casei BL23 peptidoglycan.Deletion of the two endopeptidases, Lc-75 and Lc-p45, resulted in a complete loss ofdisaccharide-dipeptide, which is a ligand of Nod-2 receptor, in the muropeptide structure of L. casei BL23, whereas deletion of Lc-p75 gene led only to a reduction of disaccharide dipeptide. The two PGH-mutants, obtained by deletion of Lc-p75 gene alone or both Lc-p75 and Lc-p45 endopeptidase genes were compared with wild type L. casei BL23 for their capacity to stimulate signaling pathways in vitro in DCs derived from human monocytes. As a consequence of DC activation by L. casei strains, four pro-inflammatory cytokines IL-6, IL-8, IL-12 and TNF-α were produced. The concentrations of secreted cytokines in response to the single Lc-p75 and Lc-p75/p45 double mutant were lower than those induced by wild type L. casei BL23.In conclusion, L. casei BL23 has a complex PGH complement. The PGHs described in this work present unique features and play important role in cell division and morphology of L. casei. Our results indicate that wild type L. casei and endopeptidase-negative mutants, which differ in their PGH content and in their PG structure, have distinct effects on human DCs, with a higher anti-inflammatory character of the endopeptidase-negative mutants
4
Egervärn, Maria. "Antibiotic resistance in Lactobacillus reuteri and Lactobacillus plantarum /". Uppsala : Swedish University of Agricultural Sciences, 2009. http://diss-epsilon.slu.se/archive/00002017/01/Acta_Thesis%2C_Egerv%C3%A4rn_090508.pdf.
Pełny tekst źródła
5
Lönnermark, Elisabet. "Lactobacilli in the normal microbiota and probiotic effects of Lactobacillus plantarum /". Göteborg : Department of Infectious Medicine, Sahlgrenska Academy, University of Gothenburg, 2010. http://hdl.handle.net/2077/21480.
Pełny tekst źródła
6
Allain, Thibault. "Rôle des Bile Salt Hydrolases (BSH) des lactobacilles probiotiques dans le contrôle de la giardiose". Thesis, Paris, AgroParisTech, 2016. http://www.theses.fr/2016AGPT0018.
Pełny tekst źródłaStreszczenie:
Giardia duodenalis est le protozoaire responsable de la giardiose, la parasitose intestinale la plus répandue dans le monde. Cette infection se caractérise par une malabsorption intestinale, des diarrhées, une perte de poids et des douleurs abdominales intenses chez l’Homme et de nombreux mammifères. Par ailleurs, cette maladie dont l’impact en santé publique et vétérinaire est reconnu, peut entraîner d’importantes déficiences nutritionnelles en particulier chez les sujets jeunes. L’infection est causée par l’ingestion de kystes de Giardia duodenalis (syn. G. lamblia, G. intestinalis) présents dans les aliments ou l’eau contaminée. Infectieux à très faibles doses, ces kystes survivent pendant plusieurs semaines dans l’environnement et sont résistants aux différents désinfectants. Suite au dékystement, la forme végétative de Giardia, le trophozoïte, adhère à l’épithélium intestinal au niveau des parties supérieures de l’intestin grêle et se multiplie, causant les symptômes. Cette phase se termine par un nouvel enkystement et l’excrétion de kystes par les fèces. Le nombre croissant d’infections liées à la contamination de l’eau potable, à l’émergence de souches résistantes aux médicaments disponibles, à la fréquence des échecs thérapeutiques et à l’importance des effets secondaires associés aux traitements font de cette maladie un sujet d’actualité de plus en plus préoccupant qui nécessite le développement de traitements alternatifs. Il est désormais bien établi que le microbiote et/ou certaines souches de bactéries probiotiques ont un impact bénéfique dans la giardiose. En particulier, la bactérie probiotique Lactobacillus johnsonii La1 (LjLa1) a un rôle protecteur contre la croissance de Giardia in vitro et in vivo. Nous avons cherché dans ce travail de Thèse à décrypter les mécanismes moléculaires associés à l’effet inhibiteur des facteurs sécrétés par LjLa1. Nous avons montré qu’in vitro, LjLa1 agissait en libérant des enzymes de type Bile Salt Hydrolases (BSH) qui modifient alors des composants de la bile non-toxiques pour le parasite (sels biliaires conjugués) en des composants toxiques (sels biliaires déconjugués). Les 3 gènes BSH codés dans le génome de LjLa1 ont été clonés chez Escherichia coli et les protéines taguées histidine purifiées pour étudier leurs propriétés biochimiques et biologiques. Obtenues sous forme active, nous avons pu en définir les spécificités de substrats et montrer qu’elles sont capables d’inhiber significativement la croissance de G. duodenalis in vitro et in vivo, dans un modèle murin de la giardiose (souriceaux OF1 non sevrés). En parallèle, nous avons identifié, à l’issue d’un large criblage de souches de lactobacilles selon leur activité anti-Giardia in vitro, une souche probiotique aux effets inhibiteurs comparables à ceux de LjLa1 : Lactobacillus gasseri CNCM-4884. Administrée in vivo dans le modèle murin de la giardiose, cette souche a réduit de 93% la charge parasitaire dans l'intestin grêle des nouveaux nés et a également réduit de façon significative le nombre de kystes libérés dans l’environnement, permettant ainsi de réduire la transmission de Giardia. Des travaux parallèles ont été réalisés au cours de ce projet de Thèse, notamment le développement d’outils de moléculaire pour l’expression hétérologue de molécules d’intérêt en santé animale chez divers lactobacilles. Le développement de ces « vecteurs mucosaux » permettra à terme de proposer une stratégie de surexpression de BSH par les lactobacilles afin d’accroitre l’activité BSH in vivo, et renforcer ainsi l’élimination du parasite. Ces résultats permettent de proposer de nouvelles pistes thérapeutiques originales contre les giardioses humaines et animales, basées sur l’utilisation de lactobacilles probiotiques ou sur les activités BSH qui en sont dérivées. Ces traitements offrent alors une alternative sérieuse aux antibiotiques et permettront de pallier aux actuels fréquents échecs thérapeutiquesGiardia duodenalis is a protozoan parasite responsible for giardiasis, the most common intestinal parasitic disease worldwide. This infection is characterized by intestinal malabsorption, diarrhea, weight loss and abdominal pain in humans and various mammalian species. Besides, this disease has a high veterinary and public health impact, leading to important nutritional deficiencies in young subjects. The infection is caused by the ingestion of food or water contaminated with infectious cysts of the parasite. Giardia cysts can survive for several weeks in the environment and are highly resistant to disinfectants. Giardia excysts in the intestinal tracts of its host and replicates under the trophozoite stage causing the symptoms. Trophozoites adhere to the intestinal epithelium of the small intestine and multiply, causing the symptoms. The cycle ends by a new encystment and infectious cysts are released in environments with feces. The increasing number of giardiasis cases, mainly due to water contaminations, the emergence of parasite strains resistant to drugs and therapeutic failures, make research on alternative therapeutic strategies and treatments highly needed. Nowadays, it is well known that the microbiota and probiotics play an important role in protection against this parasite. For instance, the probiotic strain Lactobacillus johnsonii La1 (LjLa1) prevents the establishment of Giardia in vitro and in vivo. In this thesis, we have tried to point out the molecular mechanism(s) involved in this inhibitory effect(s). We showed in vitro that LjLa1 was releasing "Bile Salt Hydrolases" (BSH) – like activities that modify some components of bile (conjugated bile salts) into toxic compounds (deconjugated bile salts) for Giardia. We have cloned and expressed each of the three bsh genes present in the genome of LjLa1 in Escherichia coli in order to study their enzymatic and biological properties. Two BSH were obtained as recombinant active enzymes and biochemical tests showed that they have distinct substrate specificities despite similar predicted 3D structures. Moreover, these two BSHs of LjLa1 exhibited anti-giardial effects in vitro and in vivo in a murine model of the giardiasis (OF1suckling mice), comforting the hypothesis of the biological role of active BSH, derived from probiotics, against Giardia. A wide collection of diverse lactobacilli strains was screened to assess their effectiveness to also display both anti-giardial and BSH activities. This screening allowed the identification of several strains exhibiting strong anti-giardial effects such as Lactobacillus gasseri CNCM I-4884. In a murine model of giardiasis, this strain dramatically reduced the parasite burden in the small intestine of treated animals and significantly reduced the number of cysts in the colon, which could contribute to blockage of parasite transmission in environments. Additional studies were realized in parallel in order to explore the potency of lactobacilli to exert beneficial effects on health. For this, molecular tools were successfully developed in various lactobacilli strains to express and deliver therapeutic molecules at mucosal surfaces. The development of these tools will further allow the overexpression of BSH by lactobacilli to increase their in vivo BSH-activity and strengthen the elimination of the parasite. Altogether, this thesis work proposes new original therapeutic strategies against human and animal giardiasis, based on the use of BSH-positive lactobacilli strains or recombinant BSH- derived from probiotic strains, to counteract the frequent therapeutic failures, offering a serious alternative to antibiotics
7
Aoudia, Nabil. "Caractérisation de l'impact de la croissance en biofilm sur l'activité probiotique de souches du genre Lactobacillus". Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOS017.
Pełny tekst źródłaStreszczenie:
Une approche in vitro a consisté à étudier la formation de biofilm de souches d’origine du genre Lactobacillus d’intérêt probiotique. Nous nous sommes également attachés à évaluer l’impact de conditions de stress mimant l’environnement intestinal sur la formation du biofilm pour l’ensemble de ces souches. Les effets antagonistes des surnageants de cultures en biofilm ou en planctonique contre des agents pathogènes alimentaires ont été appréhendés. Non seulement toutes les souches testées forment des biofilms mais ce mode de croissance génère un effet antagoniste accentué pour certaines d’entre elles. Parmi les critères de sélection des bactéries à intérêt probiotique, les effets immunomodulateurs des probiotiques sont souvent recherchés. L. casei ATCC334 connue pour ses effets anti-inflammatoires a été retenue pour notre étude. A l’aide du modèle de lignée cellulaire THP-1 et en présence de LPS, le surnageant de culture de L. casei ATCC334 cultivée en biofilm s’est avéré présenter un effet anti-inflammatoire bien supérieur à celui des cultures planctoniques. Une approche utilisant des techniques biochimique et immunologique a permis d’identifier un des principes actifs responsable de l’effet anti-inflammatoire de cette souche. L’utilisation du modèle poisson zèbre a permis de montrer la colonisation de l’intestin des larves et de confirmer le rôle anti-inflammatoire de L. casei ATCC334 avec une diminution de la production des interleukines pro-inflammatoires et une augmentation de la production d'IL-10. Le recrutement des macrophages fluorescents mesuré en cytométrie de flux est également atténué chez la larve nourrie auparavant par le probotique en présence d’un agent inflammatoire. Le résultat majeur de cette étude est l’identification de la protéine GroEL qui contribue de façon significative à l’effet anti-inflammatoire de la souche L. casei ATCC334 lorsque qu’elle est cultivée en biofilmAn in vitro approach was used to study biofilm formation by bacterial strains with probiotic properties and belonging to the Lactobacillus genus. We also evaluated the impact of stress conditions mimicking the intestinal environment on biofilm formation for all of these strains. The antagonistic effects of supernatants from cultures in biofilm or planktonic conditions against food-borne pathogens were apprehended. This growth mode generates an antagonistic effect accentuated for some of them. Among the selection criteria of interest probiotic bacteria, the immunomodulatory effects of probiotics are often sought. L. casei ATCC334 known for its anti-inflammatory effects was selected for our study. Using the model cell line THP-1 and in the presence of LPS, the culture supernatant of L. casei ATCC334 grown in biofilm was found to have an anti-inflammatory effect much greater than planktonic cultures. An approach using immunological and biochemical techniques has allowed the identification of the active substances responsible for the anti-inflammatory effect of this strain. Using the zebrafish model, we showed the colonization of the gut of the larvae and confirmed the anti-inflammatory role of L. casei ATCC334 with a decreased production of pro-inflammatory interleukins, and increased IL-10 production. Recruitment of fluorescent macrophages measured by flow cytometry was also mitigated in larvae fed previously by probotic in the presence of an inflammatory agent. The major result of this study is the identification of the GroEL protein that contributes significantly to anti-inflammatory effect of the strain L. casei ATCC334 when it is grown in biofilm
8
Storelli, Gilles. "Caractérisation de l’interaction mutualiste liant Drosophila melanogaster à son symbionte Lactobacillus plantarum". Thesis, Lyon, École normale supérieure, 2015. http://www.theses.fr/2015ENSL1041.
Pełny tekst źródłaStreszczenie:
Le microbiote a un impact majeur sur la physiologie de son hôte, cependant notre compréhension des mécanismes régulant la relation hôte/microbiote reste limitée. Nous utilisons un hôte modèle simple, la Drosophile, afin de répondre à ces questions. Durant mon doctorat, je me suis attaché à une étape particulière du cycle de vie de la Drosophile, sa phase larvaire. Celle-ci constitue sa phase de croissance et est influencée par le contexte nutritionnel. Le microbiote influence également cette étape: l’association avec la bactérie Lactobacillus plantarum tempère les effets de la carence alimentaire en soutenant un taux de croissance élevé et une maturation rapide, en modulant chez l’hôte l’activité de l’hormone Ecdysone et de l’insuline. En retour, L.plantarum bénéficie de l’association, les larvesassurant sa persistance dans la niche (la niche étant le substrat nutritif, les larves et les bactéries associées). Pour caractériser les mécanismes mis en jeu dans ce mutualisme nous avons décrit les réponses transcriptomiques et métaboliques de la larve et avons également étudié les perturbations métaboliques de la niche. Nos résultats mettent en avant l’optimisation de l’extraction des acides aminés du substrat comme facteur clef du mutualisme. L.plantarum active l’expression des protéases intestinales de l’hôte via la voie IMD/NF-κB, et bénéficierait en retour d’une quantité d’acides aminés plus importante assurant sa persistance. Ainsi, nos travaux contribuent à l’effort de compréhension desmécanismes régulant l’interaction hôte/microbiote et pourraient conduire à de nombreuses applications thérapeutiques, notamment dans le cadre de déséquilibres nutritionnelsSymbiotic bacterial populations (also called the “microbiota”) have a dramatic impact on their host’s physiology. However, our understanding of the mechanisms shaping host/microbes mutualism remains limited. We took advantage of Drosophila tractability to characterize the host’s and the microbial factors engaged in mutualism. During my PhD, I focused on the impact of the microbiota during the Drosophila larval phase, which constitutes its juvenile growth period. Drosophila larval phase is influenced by nutrition, but also by symbiotic microbes: specific association with the bacterium Lactobacillus plantarum buffers the deleterious effects of nutrient scarcity on the host’s juvenile growth, by sustaining greater growth rates and hastening maturation. L.plantarum mediate these effects by modulating the activity of the steroid hormone Ecdysone and the Insulin/Insulin-like Signaling pathway in its host. In return, L.plantarum benefits from Drosophila presence, as larvae ensure its long-term persistence in the niche (the niche being the nutritive substrate, the larvae and the bacteria dwelling on it). To characterize the mechanisms engaged in this mutualistic relationship, we described the host’s transcriptomic and metabolic responses to L.plantarum presence and characterized the metabolic perturbations occurring in the niche. Our results put forward the optimization of amino-acids extraction from the nutritive substrate as a cornerstone of mutualism. L.plantarum activates the expression of the host’s digestive proteases via IMD/NF-κB signaling and would benefit in return from an enhanced AA availability, which would help sustaining its long-term persistence. Altogether, our studies contribute to the understanding of the mechanisms regulating host/microbiota interaction and could lead to numerous therapeutic applications, notably aiming at counteracting the deleterious effects of nutritional imbalances
9
Lagrafeuille, Rosyne. "Activités anti-biofilm de Lactobacillus vis-à-vis de Klebsiella Pneumoniae". Thesis, Clermont-Ferrand 1, 2016. http://www.theses.fr/2016CLF1PP03/document.
Pełny tekst źródłaStreszczenie:
Dans la nature, les micro-organismes sont organisés en communautés agrégées dénommées biofilms, particulièrement adaptées à la survie en milieu hostile. Les difficultés pour prévenir la formation ou éliminer des biofilms matures par des stratégies conventionnelles ont encouragé le développement de nouvelles approches inspirées des mécanismes de compétition entre différents micro-organismes au sein de biofilms naturels. Au cours de ce travail, nous nous sommes intéressés à l'effet anti-biofilm de bactéries bénéfiques appartenant aux genres Lactobacillus et Bifidobacterium. Dans un premier temps, nous avons testé l'effet anti-biofilm de surnageants neutralisés vis-à-vis de deux pathogènes Klebsiella pneumoniae et Staphylococcus epidermidis dans un modèle expérimental statique. Si les extraits des quelques souches de Bifidobacterium testées stimulaient la formation de biofilm par K. pneumoniae sur surface abiotique, la majorité de ceux des 140 souches de Lactobacillus exerçait un effet inhibiteur et nous avons retenu une des souches dont le surnageant de culture entraînait une inhibition majeure (70%), Lactobacillus plantarum CIRM653. Cet extrait s'est également avéré capable de disperser des biofilms préformés à K. pneumoniae sur surface abiotique mais aussi d’inhiber la formation de biofilms sur surface biotique, et ce indépendamment d’un effet bactéricide. La formation de biofilms mixtes formés par L. plantarum et K. pneumoniae dans des modèles expérimentaux cinétiques a permis, comparativement à l'observation de biofilms mono-espèce à K. pneumoniae, de mettre en évidence des défauts de structuration du biofilm associés à une diminution de la biomasse de K. pneumoniae et une augmentation de celle de L. plantarum. Grâce à une approche transcriptionnelle ciblée, nous avons montré que L. plantarum induisait, par le biais de son surnageant, des modifications de l’expression de gènes impliqués dans la formation de biofilm chez K. pneumoniae. Quatre gènes impliqués dans le quorum-sensing (opérons lsr) étaient sous-exprimés et trois gènes de structure du pilus de type 3 étaient sur-exprimés. L'augmentation de la production de pili de type 3 fonctionnels a été validée par Western-blot et des tests d’hémagglutination. Cette surexpression est probablement responsable du niveau élevé des capacités d’adhésion sur surface abiotique d'agrégats de K. pneumoniae issus de la dispersion induite par L. plantarum.Le comportement des deux souches a également été testé in vivo, dans un modèle murin de colonisation intestinale par K. pneumoniae avec administration orale quotidienne de L. plantarum. Le dénombrement du pathogène dans les selles des animaux a montré qu'en présence de L. plantarum, K. pneumoniae maintient des niveaux de colonisation élevés, contrairement au contrôle (sans Lactobacillus) où une diminution graduelle est observée.Enfin, nous avons initié le développement d'un modèle expérimental tripartite permettant d'associer les deux partenaires bactériens avec des cellules épithéliales dans un système en flux continu. La réponse spécifique des cellules eucaryotes a également été abordée : nous avons pu mettre en évidence que L. plantarum exerçait un effet inhibiteur vis-à-vis de la réponse inflammatoire épithéliale pulmonaire induite par K. pneumoniae. En conclusion, la description d'une activité anti-biofilm in vitro ne serait pas synonyme d'une réduction in vivo de la colonisation de surfaces biotiques, mais à une plus grande capacité de dissémination. Ces observations démontrent l’importance d’une expertise précise de l’action des bactéries bénéfiques et de la maitrise du ratio bénéfice-risque pour leur utilisationIn the natural environment microorganisms are organized in aggregated communities called biofilms, which are particularly adapted to the survival in harsh conditions. The difficulties to prevent the formation or elimination of mature biofilms by conventional strategies have encouraged the development of new approaches inspired by competition mechanisms occurring between microorganisms within natural biofilms.In this work, we looked for anti-biofilm effects of beneficial bacteria belonging to Lactobacillus and Bifidobacterium genus. We first tested the anti-biofilm effect of neutralized supernatants against both pathogens Klebsiella pneumoniae and Staphylococcus epidermidis in a static experimental model. The few Bifidobacterium extracts tested led to an increase in biofilm formation by K. pneumoniae on abiotic surface, whereas the majority of the 140 strains of Lactobacillus exerted an inhibitory effect. Lactobacillus plantarum CIRM653 was selected for further experiments because its culture supernatant displayed major inhibition (70%). This extract was also capable of dispersing preformed biofilms of K. pneumoniae on abiotic surface, but also able to inhibit biofilm formation on biotic surface, independently of a bactericidal effect. The formation of mixed biofilm containing L. plantarum and K. pneumoniae in kinetic experimental models highlighted the biofilm structure defects associated with a decrease of K. pneumoniae biomass and an increase of that of L. plantarum, compared to a monospecies K. pneumoniae biofilm. Targeted transcriptional approach was used to assess changes in the expression of genes involved in biofilm formation by K. pneumoniae after contact with L. plantarum supernatant. Four genes involved in quorum-sensing (operons lsr) were under-expressed and three type 3 pili structural genes were over-expressed. The increase of functional surface located type 3 pili was validated by Western blotting and hemagglutination tests. This overexpression was probably responsible for the observed high level of adhesion capacity to abiotic surfaces of K. pneumoniae aggregates recovered after dispersion induced by L. plantarum.The behavior of the two strains was also tested in vivo in a K. pneumoniae murine intestinal colonization model with daily oral administration of L. plantarum. Viable cells counting of the pathogen in the animals’ feces showed that K. pneumoniae maintained high levels of colonization in the presence of L. plantarum, unlike the control (without Lactobacillus) where a gradual decrease was observed.Finally, we initiated the development of a tripartite experimental model allowing the combination of the two bacterial partners with epithelial cells in a continuous flow system. In parallel, the specific response of eukaryotic cells to these bacteria was addressed: L. plantarum exerted an inhibitory effect on the pulmonary epithelial inflammatory response induced by K. pneumoniae.In conclusion, these results highlight the discrepancy between in vitro anti-biofilm activity of L. plantarum and its in vivo behavior leading to increased dissemination of the pathogen. Substantial expertise of beneficial bacteria is therefore necessary to fully assess their benefit-risk ratio
10
Lamarque, Mauld. "Spécificité du transport et de l'hydrolyse des peptides chez les bactéries lactiques : aspects nutritionnel et moléculaire". Lyon 1, 2003. http://www.theses.fr/2003LYO10213.
Pełny tekst źródłaStreszczenie:
Pour se développér dans le lait, les bactéries lactiques possèdent un système protéolytique comprenant une protéiase de surface PrtP, un transporteur d'oligopeptides Opp et des peptidases cytoplasmiques. Pour mieux comprendre le contôle de ce système par des peptides du milieu extracellualire, nous avons étudié la spécificité du transport des peptides chez les lactocoques. Cette spécificité est différente selon les souches et ne repose pas exclusivement sur le système Opp. Elle pourrait dépendre d'un second transporteur, Opt, dont la spécificité recouvre partiellement celle d'Opp et dont la biosynthèse est variable selon les souches. La source de carbone joue aussi un rôle sur l'expression de certains composants du système protéolytique. En effet, chez Lactobacillus bulgaricus, l'expression du géne pepQ est soumise à un mécanisme d'activation catabolique, dépendant d'une protéine CcpA-like (PepR1) et de la séquence cre située en amont du promoteur du géne pepQ.
Książki na temat "Lactobacillus"
1
Linders, Leonie J. M. Drying of Lactobacillus plantarum. [s.l.]: [s.n.], 1996.
Znajdź pełny tekst źródła
2
Campos, Alba I. Perez, i Arturo Leon Mena. Lactobacillus: Classification, uses and health implications. Hauppauge, N.Y: Nova Science Publisher's, 2012.
Znajdź pełny tekst źródła
3
Ling, Wen-Hua. Effect of lactobacilli-containing vegan diet and Lactobacillus GG on colonic chemical loading in man. Kuopio: University of Kuopio, 1992.
Znajdź pełny tekst źródła
4
Åsa, Ljungh, i Wadström Torkel, red. Lactobacillus molecular biology: From genomics to probiotics. Norfolk, UK: Caister Academic, 2009.
Znajdź pełny tekst źródła
5
Wall, Torun. Environmental interactions of Lactobacillus reuteri: Signal transduction, gene expression and extracellular proteins of a lactic acid bacterium. Uppsala: Swedish University of Agricultural Sciences, 2005.
Znajdź pełny tekst źródła
6
Heath, Catherine M. The enzymology of N-deoxyribosyltransferase from Lactobacillus leichmannii. [s.l.]: typescript, 1991.
Znajdź pełny tekst źródła
7
G, Hoover Dallas, i Steenson Larry R, red. Bacteriocins of lactic acid bacteria. San Diego: Academic Press, 1993.
Znajdź pełny tekst źródła
8
Korpela, Riitta. Role of rye fibre and Lactobacillus GG in colonic metabolis. Kuopio: University of Kuopio, 1995.
Znajdź pełny tekst źródła
9
B, Wood Brian J., i Holzapfel W. H, red. The genera of lactic acid bacteria. London: Blackie Academic & Professional, 1995.
Znajdź pełny tekst źródła
10
Cardy, Susan Mary. Lactobacillus leichmannii as a probe for the quantitation of vitamin B-12. [s.l.]: typescript, 1989.
Znajdź pełny tekst źródłaCzęści książek na temat "Lactobacillus"
1
Bährle-Rapp, Marina. "Lactobacillus acidophilus". W Springer Lexikon Kosmetik und Körperpflege, 308. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5758.
Pełny tekst źródła
2
Bährle-Rapp, Marina. "Lactobacillus Ferment". W Springer Lexikon Kosmetik und Körperpflege, 308. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5761.
Pełny tekst źródła
3
Hammes, W. P., i R. F. Vogel. "The genus Lactobacillus". W The Genera of Lactic Acid Bacteria, 19–54. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-5817-0_3.
Pełny tekst źródła
4
Bährle-Rapp, Marina. "Lactobacillus/Algae Ferment". W Springer Lexikon Kosmetik und Körperpflege, 308. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5759.
Pełny tekst źródła
5
Bährle-Rapp, Marina. "Lactobacillus/Lac Ferment". W Springer Lexikon Kosmetik und Körperpflege, 309. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5764.
Pełny tekst źródła
6
Bährle-Rapp, Marina. "Lactobacillus/Phophyridium Ferment". W Springer Lexikon Kosmetik und Körperpflege, 309. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5766.
Pełny tekst źródła
7
Bährle-Rapp, Marina. "Lactobacillus/Skeletonema Ferment". W Springer Lexikon Kosmetik und Körperpflege, 309. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5767.
Pełny tekst źródła
8
Pot, Bruno, Giovanna E. Felis, Katrien De Bruyne, Effie Tsakalidou, Konstantinos Papadimitriou, Jørgen Leisner i Peter Vandamme. "The genus Lactobacillus". W Lactic Acid Bacteria, 249–353. Chichester, UK: John Wiley & Sons, Ltd, 2014. http://dx.doi.org/10.1002/9781118655252.ch19.
Pełny tekst źródła
9
Chassy, Bruce M., i Cynthia M. Murphy. "Lactococcus and Lactobacillus". W Bacillus subtilis and Other Gram-Positive Bacteria, 65–82. Washington, DC, USA: ASM Press, 2014. http://dx.doi.org/10.1128/9781555818388.ch5.
Pełny tekst źródła
10
Bährle-Rapp, Marina. "Lactobacillus/Eichornia Crassipes Ferment". W Springer Lexikon Kosmetik und Körperpflege, 308. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_5760.
Pełny tekst źródłaStreszczenia konferencji na temat "Lactobacillus"
1
Faskhutdinova, Elizaveta, Irina Milentyeva i Larisa Proskuryakova. "STUDY OF BIOCOMPATIBILITY OF PROBIOTIC STRAINS OF MICROORGANISMS IN ORDER TO CREATE A BIOLOGICALLY ACTIVE FOOD ADDITIVE". W I International Congress “The Latest Achievements of Medicine, Healthcare, and Health-Saving Technologies”. Kemerovo State University, 2023. http://dx.doi.org/10.21603/-i-ic-136.
Pełny tekst źródłaStreszczenie:
The purpose of this work is to study the biocompatibility of probiotic strains Lactobacillus
plantarum B-1615, Lactobacillus brevis B-2429, Bacillus subtilis B-7918, Enterococcus faecium B5000 and Lactobacillus paracasei B-2430 to create a biologically active supplement. A drip technique
was used to study biocompatibility. It was found that biocompatibility is possessed by combinations of
strains Lactobacillus plantarum B-1615 and Lactobacillus brevis B-2429; Lactobacillus plantarum B1615 and Bacillus subtilis 21 B-7918; Lactobacillus plantarum B-1615 and Lactobacillus paracasei B2430; Lactobacillus brevis B-2429 and Enterococcus faecium B -5000; Lactobacillus brevis B-2429 and
Lactobacillus paracasei B-2430; Bacillus subtilis 21 B-7918 and Enterococcus faecium B-5000.
2
DALCANTON, F., F. R. S. MACHADO JR, D. A. LONGHI, B. A. M. CARCIOFI, J. B. LAURINDO i G. M. F. ARAGÃO. "MATHEMATICAL MODELING OF LACTOBACILLUS VIRIDESCENS AND LACTOBACILLUS SAKEI GROWTH AT SIX DIFFERENT TEMPERATURES". W XX Congresso Brasileiro de Engenharia Química. São Paulo: Editora Edgard Blücher, 2015. http://dx.doi.org/10.5151/chemeng-cobeq2014-1407-19439-141560.
Pełny tekst źródła
3
Cvetković, Dragoljub, Aleksandra Ranitović, Tara Budimac i Olja Šovljanski. "EXAMINATION OF THE SURVIVAL OF Lactobacillus plantarum AND Lactobacillus rhamnosus DURING KOMBUCHA FERMENTATION". W 2nd International Symposium on Biotechnology. University of Kragujevac, Faculty of Agronomy, 2024. http://dx.doi.org/10.46793/sbt29.52dc.
Pełny tekst źródłaStreszczenie:
Kombucha is a traditional fermented beverage, which is usually prepared by fermenting sweetened black tea using a symbiotic consortium of acetic acid bacteria and yeasts. Kombucha exhibits several functional properties, it still can’t be labelled as a probiotic product. In this study, Lactobacillus plantarum and Lactobacillus rhamnosus were added separately at the start of the fermentation to examine their survival during fermentation conditions. Microbiological and chemical parameters were tested during 5 days of Kombucha fermentation. Sample inoculated with L. plantarum demonstrated better survivability, but number was not enough to label the beverage as probiotic.
4
Buyong, Muhamad Ramdzan, Farhad Larki, Norazreen Abd Aziz, Jumril Yunas, Azrul Azlan Hamzah i Burhanuddin Yeop Majlis. "Dielectrophoretic force response for Lactobacillus Casei". W 2016 IEEE International Conference on Semiconductor Electronics (ICSE). IEEE, 2016. http://dx.doi.org/10.1109/smelec.2016.7573585.
Pełny tekst źródła
5
Wu, Jain-Shing, Chien-Chang Wu i Chien-Sen Liao. "Lactobacillus Fermentation Prediciton Using Convolution Nerual Network". W 2022 IEEE International Conference on Consumer Electronics - Taiwan. IEEE, 2022. http://dx.doi.org/10.1109/icce-taiwan55306.2022.9869168.
Pełny tekst źródła
6
Wu, JainShing, Chien-Chang Wu i Chien-Sen Liao. "Novel Lactobacillus Fermentation Prediction Using Deep Learning". W 2021 7th International Conference on Applied System Innovation (ICASI). IEEE, 2021. http://dx.doi.org/10.1109/icasi52993.2021.9568412.
Pełny tekst źródła
7
Grebenshchikova, A. V., A. N. Irkitova i D. E. Dudnik. "Valuable biotechnological properties of Lactobacillus acidophilus strains". W ACTUAL PROBLEMS OF ORGANIC CHEMISTRY AND BIOTECHNOLOGY (OCBT2020): Proceedings of the International Scientific Conference. AIP Publishing, 2022. http://dx.doi.org/10.1063/5.0069214.
Pełny tekst źródła
8
Chen, He, Liyuan Ji, Guowei Shu, Zhe Ji, Tao Qin i Qi Ma. "Notice of Retraction: Effect of Steroidal Saponins from Fructus Tribuli on Growth of Lactobacillus casei and Lactobacillus reuteri". W 2011 5th International Conference on Bioinformatics and Biomedical Engineering. IEEE, 2011. http://dx.doi.org/10.1109/icbbe.2011.5780696.
Pełny tekst źródła
9
Erliana, Whiny, Tri Widjaja, Ali Altway, Maria Sandra i Daryl Susilo. "The effects of various pH and temperature to enhance lactic acid production using Lactobacillus casei and Lactobacillus rhamnosus". W PROCEEDINGS OF 2ND INTERNATIONAL CONFERENCE ON CHEMICAL PROCESS AND PRODUCT ENGINEERING (ICCPPE) 2019. AIP Publishing, 2020. http://dx.doi.org/10.1063/1.5140932.
Pełny tekst źródła
10
D.S., Chelombitskaya, Rudoy D.V., Olshevskaya A.V., Odabashyan M.Yu. i Vershinina A.V. "INFLUENCE OF PROBIOTIC BACTERIA LACTOBACILLUS RHAMNOSUS L108 ON HOST GENE EXPRESSION (IN THE CAENORHABDITIS ELEGANS MODEL)." W II INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE "DEVELOPMENT AND MODERN PROBLEMS OF AQUACULTURE" ("AQUACULTURE 2022" CONFERENCE). DSTU-Print, 2022. http://dx.doi.org/10.23947/aquaculture.2022.165-167.
Pełny tekst źródłaStreszczenie:
The article presents a study of the effect of the probiotic bacterium Lactobacillus rhamnosus L108 on the expression of host longevity genes in the Caenorhabditis elegans model. The study found that the Lactobacillus rhamnosus L108 strain increased the lifespan of Caenorhabditis elegans by 9.6%. Also, when analyzing longevity genes, an increase in the level of expression of the sir-2.1, skn-1, and daf-16 genes, which underlie the regulation of conservative signaling protective pathways of insulin/insulin-like factor-1 and p38 MAPK, was observed.
Raporty organizacyjne na temat "Lactobacillus"
1
Nemska, Veronica, Nelly Georgieva, Jeny Miteva-Staleva, Ekaterina Krumova i Svetla Danova. Antifungal Activity of Lactobacillus spp. from Traditional Bulgarian Dairy Products. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, grudzień 2019. http://dx.doi.org/10.7546/crabs.2019.12.10.
Pełny tekst źródła
2
Taylor, Craig. Physical and kinetic properties of dihydroorotate dehydrogenase from Lactobacillus bulgaricus. Portland State University Library, styczeń 2000. http://dx.doi.org/10.15760/etd.62.
Pełny tekst źródła
3
Barstad, Louise. Purification and characterization of NADH oxidase and peroxidase from Lactobacillus casei. Portland State University Library, styczeń 2000. http://dx.doi.org/10.15760/etd.2785.
Pełny tekst źródła
4
Indrio, Flavia. Beneficios de Lactobacillus reuteri DSM 17983 en los trastornos digestivos funcionales de la infancia. Buenos Aires: siicsalud.com, luty 2015. http://dx.doi.org/10.21840/siic/144143.
Pełny tekst źródła
5
Cheng, Yonglang, Peng Zeng, Zhiwei Huang, Hao Shi, Tianying Cai, Tongxi Li, Yifan Chen, Wenguang Fu i Qiu Li. Lactobacillus reuteri alleviates lipid levels in patients with hypercholesterolemia: a meta-analysis of randomized controlled trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, kwiecień 2022. http://dx.doi.org/10.37766/inplasy2022.4.0160.
Pełny tekst źródła
6
Osman, Mohamed, Judith Stabel, Jesse M. Hostetter, Daniel S. Nettleton i Donald C. Beitz. Probiotic Lactobacillus acidophilus strain NP51® Curtails the Progression of Mycobacterium avium Subspecies paratuberculosis (MAP) Infection in Balb/c mice. Ames (Iowa): Iowa State University, styczeń 2011. http://dx.doi.org/10.31274/ans_air-180814-66.
Pełny tekst źródła
7
Osman, Mohamed, Judith Stabel, Jesse M. Hostetter, Daniel S. Nettleton i Donald C. Beitz. Prevention of Mycobacterium avium Subspecies paratuberculosis (MAP) Infection in Balb/c mice by Feeding Lactobacillus acidophilus Strain NP-51®. Ames (Iowa): Iowa State University, styczeń 2010. http://dx.doi.org/10.31274/ans_air-180814-944.
Pełny tekst źródła
8
Weinberg, Zwi G., Adegbola Adesogan, Itzhak Mizrahi, Shlomo Sela, Kwnag Jeong i Diwakar Vyas. effect of selected lactic acid bacteria on the microbial composition and on the survival of pathogens in the rumen in context with their probiotic effects on ruminants. United States Department of Agriculture, styczeń 2014. http://dx.doi.org/10.32747/2014.7598162.bard.
Pełny tekst źródłaStreszczenie:
This research project was performed in context of the apparent probiotic effect of selected lactic acid bacteria (LAB) silage inoculants on the performance of ruminants (improved feed intake, faster live-weight gain, higher milk yields and improved feed efficiency). The overall objective was to find out how LAB affect ruminant performance. The project included several “chapters” as follows: 1. The effect of LAB silage inoculants on the survival of detrimental bacteria in rumen fluid, in vitro study (Weinberg et al., The Volcani Center). An in vitro model was developed to study the interaction between selected LAB and an E. coli strain tagged with green fluorescence protein (GFP) in buffered RF. Results indicated that both LAB inoculants and E. coli survived in the RF for several days; both LAB inoculants and LAB-treated silages did not affect survival of E. coli in rumen fluid in vitro. The effect of feeding baled wheat silages treated with or without three selected LAB silage inoculants on the performance of high-lactating cows (Weinberg et al., The Volcani Center). Treatments included control (no additive), Lacobacillusbuchneri40788 (LB), Lactobacillus plantarumMTD1 40027 (LP) and Pediococcuspentosaceus30168 (PP), each applied at 10⁶ cfu/g FM. The silages were included in the TMR of 32 high milking Holstein cows in a controlled feeding experiment. All baled silages were of good quality. The LB silage had the numerically highest acetic acid and were the most stable upon aerobic exposure. The cows fed the LB silages had the highest daily milk yields, percent milk fat and protein. The microbiome of baled wheat silages and changes during ensiling of wheat and corn (Sela et al., The Volcani Center). Bacterial community of the baled silages was dominated mainly of two genera in total, dominated by Lactobacillus and Clostridium_sensu_stricto_12 with 300 other genera at very low abundance. Fungal community was composed mainly of two genera in total, dominated by Candida and Monascuswith 20 other genera at very low abundance. In addition, changes in the microbiome during ensiling of wheat and corn with and without addition of L. plantarumMTD1 was studied in mini-silos. Overall 236 bacterial genera were identified in the fresh corn but after 3 months Lactobacillus outnumbered all other species by acquiring 95% of relative abundance. The wheat silage samples are still under analysis. The effect of applying LAB inoculants at ensiling on survival of E. coli O157:H7 in alfalfa and corn silages(Adesogan et al., University of Florida). E. coli (10⁵ cfu/g) was applied to fresh alfalfa and corn at ensiling with or without L. plantarumor L. buchneri. The pathogen was added again after about 3 moths at the beginning of an aerobic exposure period. The inoculants resulted in faster decrease in pH as compared with the control (no additives) or E. coli alone and therefore, the pathogen was eliminated faster from these silages. After aerobic exposure the pathogen was not detected in the LAB treated silages, whereas it was still present in the E. coli alone samples. 5. The effect of feeding corn silage treated with or without L. buchnerion shedding of E. coli O157:H7 by dairy cows (Adesogan et al., UFL). BARD Report - Project 4704 Page 2 of 12 Five hundred cows from the dairy herd of the University of Florida were screened for E. coli shedding, out of which 14 low and 13 high shedders were selected. These cows were fed a total mixed ration (TMR) which was inoculated with E. coli O157:H7 for 21 days. The TMR included corn silage treated with or without L. buchneri. The inoculated silages were more stable upon aerobic exposure than the control silages; the silage inoculant had no significant effect on any milk or cow blood parameters. However, the silage inoculant tended to reduce shedding of E. coli regardless of high or low shedders (p = 0.06). 6. The effect of feeding baled wheat silages treated with or without three selected LAB silage inoculants on the rumen microbiome (Mizrahi et al., BGU). Rumen fluid was sampled throughout the feeding experiment in which inoculated wheat silages were included in the rations. Microbial DNA was subsequently purified from each sample and the 16S rRNA was sequenced, thus obtaining an overview of the microbiome and its dynamic changes for each experimental treatment. We observed an increase in OTU richness in the group which received the baled silage inoculated with Lactobacillus Plantarum(LP). In contrast the group fed Lactobacillus buchneri(LB) inoculated silage resulted in a significant decrease in richness. Lower OTU richness was recently associated in lactating cows with higher performance (Ben Shabatet al., 2016). No significant clustering could be observed between the different inoculation treatments and the control in non metric multi-dimentional scaling, suggesting that the effect of the treatments is not the result of an overall modulation of the microbiome composition but possibly the result of more discrete interactions. Significant phylum level changes in composition also indicates that no broad changes in taxa identity and composition occurred under any treatment A more discrete modulation could be observed in the fold change of several taxonomic groups (genus level analysis), unique to each treatment, before and after the treatment. Of particular interest is the LB treated group, in which several taxa significantly decreased in abundance. BARD Report - Project 4704 Page 3 of 12
9
Weinberg, Zwi G., Richard E. Muck, Nathan Gollop, Gilad Ashbell, Paul J. Weimer i Limin Kung, Jr. effect of lactic acid bacteria silage inoculants on the ruminal ecosystem, fiber digestibility and animal performance. United States Department of Agriculture, wrzesień 2003. http://dx.doi.org/10.32747/2003.7587222.bard.
Pełny tekst źródłaStreszczenie:
The overall objective of the whole research was to elucidate the mechanisms by which LAB silage inoculants enhance ruminant performance. The results generated will permit the development of better silage inoculants that maximize both silage preservation and animal performance. For this one-year BARD feasibility study, the objectives were to: 1. determine whether lactic acid bacteria (LAB) used in inoculants for silage can survive in rumen fluid (RF) 2.select the inoculants that survived best, and 3. test whether LAB silage inoculants produce bacteriocins-like substances. The most promising strains will be used in the next steps of the research. Silage inoculants containing LAB are used in order to improve forage preservation efficiency. In addition, silage inoculants enhance animal performance in many cases. This includes improvements in feed intake, liveweight gain and milk production in 25-40% of studies reviewed. The cause for the improvement in animal performance is not clear but appears to be other than direct effect of LAB inoculants on silage fermentation. Results from various studies suggest a possible probiotic effect. Our hypothesis is that specific LAB strains interact with rumen microorganisms which results in enhanced rumen functionality and animal performance. The first step of the research is to determine whether LAB of silage inoculants survive in RF. Silage inoculants (12 in the U.S. and 10 in Israel) were added to clarified and strained RF. Inoculation rate was 10 ⁶ (clarified RF), 10⁷ (strained RF) (in the U.S.) and 10⁷, 10⁸ CFU ml⁻¹ in Israel (strained RF). The inoculated RF was incubated for 72 and 96 h at 39°C, with and without 5 g 1⁻¹ glucose. Changes in pH, LAB numbers and fermentation products were monitored throughout the incubation period. The results indicated that LAB silage inoculants can survive in RF. The inoculants with the highest counts after 72 h incubation in rumen fluid were Lactobacillus plantarum MTD1 and a L. plantarum/P. cerevisiae mixture (USA) and Enterococcus faecium strains and Lactobacillus buchneri (Israel). Incubation of rumen fluid with silage LAB inoculants resulted in higher pH values in most cases as compared with that of un-inoculated controls. The magnitude of the effect varied among inoculants and typically was enhanced with the inoculants that survived best. This might suggest the mode of action of LAB silage inoculants in the rumen as higher pH enhances fibrolytic microorganisms in the rumen. Volatile fatty acid (VFA) concentrations in the inoculated RF tended to be lower than in the control RF after incubation. However, L. plalltarull1 MTDI resulted in the highest concentrations of VFA in the RF relative to other inoculants. The implication of this result is not as yet clear. In previous research by others, feeding silages which were inoculated with this strain consistently enhanced animal performance. These finding were recently published in Weinberg et.al.. (2003), J. of Applied Microbiology 94:1066-1071 and in Weinberg et al.. (2003), Applied Biochemistry and Biotechnology (accepted). In addition, some strains in our studies have shown bacteriocins like activity. These included Pediococcus pentosaceus, Enterococcus faecium and Lactobacillus plantarum Mill 1. These results will enable us to continue the research with the LAB strains that survived best in the rumen fluid and have the highest potential to affect the rumen environment.
10
Asvapathanagul, Pitiporn, Leanne Deocampo i Nicholas Banuelos. Biological Hydrogen Gas Production from Food Waste as a Sustainable Fuel for Future Transportation. Mineta Transportation Institute, lipiec 2022. http://dx.doi.org/10.31979/mti.2021.2141.
Pełny tekst źródłaStreszczenie:
In the global search for the right alternative energy sources for a more sustainable future, hydrogen production has stood out as a strong contender. Hydrogen gas (H2) is well-known as one of the cleanest and most sustainable energy sources, one that mainly yields only water vapor as a byproduct. Additionally, H2 generates triple the amount of energy compared to hydrocarbon fuels. H2 can be synthesized from several technologies, but currently only 1% of H2 production is generated from biomass. Biological H2 production generated from anaerobic digestion is a fraction of the 1%. This study aims to enhance biological H2 production from anaerobic digesters by increasing H2 forming microbial abundance using batch experiments. Carbon substrate availability and conversion in the anaerobic processes were achieved by chemical oxygen demand and volatile fatty acids analysis. The capability of the matrix to neutralize acids in the reactors was assessed using alkalinity assay, and ammonium toxicity was monitored by ammonium measurements. H2 content was also investigated throughout the study. The study's results demonstrate two critical outcomes, (i) food waste as substrate yielded the highest H2 gas fraction in biogas compared to other substrates fed (primary sludge, waste activated sludge and mixed sludge with or without food waste), and (ii) under normal operating condition of anaerobic digesters, increasing hydrogen forming bacterial populations, including Clostridium spp., Lactococcus spp. and Lactobacillus spp. did not prolong biological H2 recovery due to H2 being taken up by other bacteria for methane (CH4) formation. Our experiment was operated under the most optimal condition for CH4 formation as suggested by wastewater operational manuals. Therefore, CH4-forming bacteria possessed more advantages than other microbial populations, including H2-forming groups, and rapidly utilized H2 prior to methane synthesis. This study demonstrates H2 energy renewed from food waste anaerobic digestion systems delivers opportunities to maximize California’s cap-and-trade program through zero carbon fuel production and utilization.