Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Aquicultura, Florianópolis, 2011 / Made available in DSpace on 2012-10-26T04:18:02Z (GMT). No. of bitstreams: 1 294815.pdf: 393747 bytes, checksum: 54fd2a5da055c3d8d5184275a8d7caa8 (MD5) / O objetivo deste trabalho foi avaliar o uso de prebiótico (inulina), probiótico (Lactobacillus plantarum) e simbiótico (Lactobacillus plantarum + inulina) no crescimento, microbiota intestinal, reposta imune e resistência ao desafio experimental com Vibrio alginolyticus em camarões Litopenaeus vannamei. A concentração de Vibrio spp. no trato digestório foi significativamente menor em camarões alimentados com dieta suplementada com prebiótico, probiótico e simbiótico, enquanto que a concentração de bactérias ácido lácticas foi significativamente superior somente nos camarões alimentados com probiótico e simbiótico. O valor aglutinante do soro frente à Vibrio alginolyticus foi significativamente maior no grupo probiótico e simbiótico antes da infecção, e maior em todos os tratamentos após infecção em relação ao controle. O número de hemócitos, a atividade da fenolixidase e a atividade antibacteriana do soro dos camarões não apresentaram diferenças significativas nos tratamentos comparados com o controle. Igualmente, não houve diferença no crescimento ou na sobrevivência dos camarões ao desafio por V. alginolyticus. Conclui-se que dietas probióticas, prebióticas e simbióticas, alteram a microbiota intestinal aumentando o título aglutinante do soro contra V. alginolyticus, contudo sem alterar o crescimento dos camarões ou a sobrevivência ao desafio por V. alginolyticus.

1. Ištirtos registruotos Lactobacillus plantarum U-14, kuri išskirta iš sveikos karvės makšties ir Lactobacillus fermentum U-5, kuri išskirta iš sveiko veršelių fekalijų, padermės, nustatytos jų optimalios kultivavimo temperatūros, įvertintos jų probiotinės savybės, nustatytas antagonistinis aktyvumas, atsparumas antibiotikams bei įvertinta liofilizacijos įtaka šioms laktobacilų padermėms. 2. Liofilizacijos būdu pagamintas probiotikas, sudarytas iš Lactobacillus plantarum U-14 ir Lactobacillus fermentum U-5 padermių, nustatytas laktobacilų gyvybingumas preparate laikant vienus metus +4oC temperatūroje. 3. Nustatyta probiotiko profilaktinė dozė naujagimiams veršeliams girdant su krekenomis arba pienu pirmas 10 gyvenimo dienų, stebint veršelių klinikinius požymius, įvertinant paros priesvorį, įtaką bendram enterobakterijų ir laktobacilų kiekiui bei nustatant laktobacilų rūšinę sudėtį fekalijose įvertinant kraujo morfologinius ir biocheminius parametrus.4. Nustatyta probiotiko profilaktinė dozė veršeliams, kuri buvo – 4g/d. ir ji palyginta su probiotiko Yeasture profilaktine doze. / 1.The registered strains of Lactobacillus plantarum U-14 isolated from the vagina of healthy cow and Lactobacillus fermentum U-5 isolated from the faeces of healthy calve were studied, the optimal temperature for the cultivation was defined, were evaluated their probiotic properties, the antagonistic activity, resistance to antibiotics and the effect of lyophilization on these strains of lactobacillus were studied. 2.The probiotic preparation, consisting of Lactobacillus plantarum U-14 and Lactobacillus fermentum U-5 strains was produced by the method of lyophilization and the viability of lactobacillus during the period of 1 year storage at +4oC temperature was defined. 3.The preventive dose of probiotic preparation for neonate calves given with colostrum or milk was defined during the first 10 days, the clinical signs of calves, daily weight gain, effect on the total number of enterobacteria and lactobacillus were studied and the lactobacillus species composition in the faeces together evaluating morphological and biochemical indicators of blood was investigated. 4.The defined dose of probiotic preparation for calves was – 4g/d. and it was compared to the preventive dose of the preparation Yeasture.

Diss. (sammanfattning) Umeå : Univ., 2007. / Härtill 4 uppsatser.

Cyclopropanation of the unsaturated fatty acid moieties of membrane phospholipids is a commonly observed phenomenon in a number of bacterial systems. The cyclopropane fatty acids are usually synthesized during and after the transition from exponential growth to stationary phase, or under such environmental conditions as acidic culture pH, low oxygen tension or high salt concentrations. S-Adenosylmethionine, the ubiquitous methyl group donor, provides the methylene bridge carbon in the reaction catalyzed by cyclopropane fatty acid synthase. Also formed in the reaction is S-adenosylhomocysteine, a potent inhibitor of cyclopropane fatty acid synthase, which is degraded by S-adenosylhomocysteine nucleosidase. This work provides evidence for at least two modes of regulation of lactobacillic acid synthesis, the cyclopropane fatty acid formed from cis-vaccenic acid (cis-11,12-octadecenoic acid), in Lactobacillus piantarum.

Thesis (MSc (Microbiology))--Stellenbosch University, 2008. / Lactobacillus plantarum JW3BZ and Lactobacillus fermentum JW15BZ isolated from boza, a Bulgarian cereal based fermented beverage, produce bacteriocins JW3BZ and JW15BZ active against a wide range of food spoilage and pathogenic bacteria. Strains JW3BZ and JW15BZ are resistant to low pH (pH 2.0–4.0). Both strains grow well in MRS broth with an initial pH ranging from 5.0 to 10.0. Strain JW3BZ displayed intrinsic resistance to bile salts. Strain JW15BZ, on the other hand, is sensitive to bile salts exceeding concentrations of 0.3% (w/v). Both strains are weakly hydrophobic and are resistant to a wide range of antibiotics, antiinflammatory drugs and painkillers. Strains JW3BZ and JW15BZ adhered at 4% to Caco-2 cells and they did not compete with Listeria monocytogenes Scott A for adhesion. A homologue of MapA, a gene known to play a role in adhesion, was detected in L. plantarum JW3BZ. Both strains have high auto- and co-aggregation properties. Bacteriocin JW15BZ was partially purified with ammonium sulfate, followed by separation on Sep-Pak C18 and reverse phase High Pressure Liquid Chromatography (HPLC). Two separate peaks with antimicrobial activity were recorded for bacteriocin JW15BZ, suggesting that it consists of at least two antimicrobial peptides. Lactobacillus plantarum JW3BZ contains genes homologous to plnE, plnF and plnI of the plnEFI operon that encode for two small cationic bacteriocin-like peptides with double-glycine-type leader peptides and its respective immunity proteins. The antimicrobial activity displayed by strain JW3BZ may thus be ascribed to the production of plantaricins E and F. Bacteriocin JW3BZ and JW15BZ displayed activity against herpes simplex virus (HSV-1) (EC50=200 μg/ml). Both strains were identified in boza after 7 days at storage at 4 oC and repressed the growth of Lactobacillus sakei DSM 20017, indicating that the bacteriocins are produced in situ. The sensory attributes of boza prepared with different starter cultures did not vary considerably, although statistical differences were observed for acidity and yeasty aroma. Encapsulation of strain JW3BZ and JW15BZ in 2% sodium alginate protected the cells from low pH (1.6) and 2.0% (w/v) bile. The rate at which cells were released from the matrix varied, depending on the conditions. Better survival of strains JW3BZ and JW15BZ encapsulated in 2% (w/v) alginate was observed during 9 h in a gastro-intestinal model. Highest release of cells was observed at conditions simulating colonic pH (pH 7.4), starting from 56-65% during the first 30 min, followed by 87%. Complete (100%) release was recorded after 2.5 h at these conditions. Strains JW3BZ and JW15BZ could be used as starter cultures in boza. The broad spectrum of antimicrobial activity of bacteriocins JW3BZ and JW15BZ is an added advantage, rendering the cells additional probiotic properties. Encapsulation of the cells in alginate gel increased their resistance to harsh environmental conditions and may be the ideal method to deliver viable cells in vivo.

The endosymbiotic bacteria Wolbachia and the gut microbiome have independently been shown to affect several aspects of insect biology, including reproduction, development, lifespan, stem cell activity and resistance to human pathogens in insect vectors. This research shows that Wolbachia, which reside mainly in the fly germline, affect the microbial species present in the gut of a lab reared strain of Drosophila melanogaster. Fruit flies host two main genera of commensal bacteria – Acetobacter and Lactobacillus. Wolbachia-infected flies have significantly reduced titers of Acetobacter. Analysis of the microbiome of axenic flies fed with equal proportions of both bacteria shows that Wolbachia’s presence is a determinant in the microbiome composition throughout fly development. This effect of Wolbachia on the Drosophila microbiome is host genotype-dependent. To investigate the mechanism of microbiome modulation, the effect of Wolbachia on Imd and ROS pathways, the main regulators of immune response in the fly gut was measured. Wolbachia’s presence did not cause significant gene expression changes of the effector molecules in either pathway. It was also found that Wolbachia slightly reduce the relative length of the acidic region of the gut. However, this observation lacks the robustness necessary to provide a mechanism for the significantly reduced Acetobacter levels. Furthermore, microbiome modulation is not due to direct interaction between Wolbachia and the gut microbes,as confocal microscopy shows that Wolbachia is absent from the gut lumen. These results indicate that the mechanistic basis of the modulation of microbiome composition by Wolbachia is more complex than direct bacteria interaction or Wolbachia’s effect on fly immunity. The findings reported here highlight the importance of considering the gut microbiome composition and host genetic background during Wolbachia-induced phenotypic studies and microbial based-disease vector control strategies.

Lactic acid bacteria (LAB), a group of generally recognized as safe (GRAS) organisms that metabolize sugars into primarily lactic acid, have traditionally been used for the fermentation and preservation of various foods and beverages. There is increasing interest in the genetic manipulation of LAB to improve existing characteristics or introduce novel, industrially pertinent phenotypes. However, because these bacteria have food-related applications, their genetic modification requires the use of food-grade genetic engineering tools. LAB plasmids, self-replicating extrachromosomal DNA molecules, can be used to derive food-grade cloning vectors. The rationale of this research was to develop a food-grade cloning vector using a lactobacilli cryptic plasmid and to investigate its cloning and expression properties. The main objectives were to (i) screen Lactobacillus spp. for plasmids, (ii) isolate and characterize a plasmid, and (iii) use the plasmid replicon to construct a cloning vector and express heterologous genes in various hosts. This is the first step in the development of a new family of food-grade cloning vectors for the genetic modification of lactobacilli.

The purpose of this study was to investigate whether resistant maltodextrin is suitable as a fiber source in the probiotic fruit drink ProViva Mango without affecting the probiotic bacterium Lactobacillus plantarum 299v, viscosity or the sensory experience of the drink. Resistant maltodextrin is produced from hydrolyzed corn starch and is classified as a soluble dietary fiber. It is relatively resistant to digestion in the small intestine, where approximately 10% can be broken down, 50% can be fermented in the colon by the intestinal flora and 40 % is excreted in the faeces. Resistant maltodextrin has several important qualities when it comes to food processing. When added in a product, it does not affect the viscosity or taste and it is heat and acid stable. Three different fiber levels were added to ProViva Mango; 5 g, 10 g and 15 g/350 ml and they were compared against a reference beverage without added fiber. ProViva has a shelf life of 30 days and therefore analyses were planned to be performed at day 1 and after 15 and 32 days. Due to lack of time analyses were only performed at day 1 and 15. The study showed that resistant maltodextrin did not affect the viscosity or the probiotic bacteria L. plantarum 299v. The sensory analysis evaluated five different parameters: sweetness, fruitiness, grittiness, mouth feel and appearance. At day 1 and 15 there was no experienced significant difference between the fiber-enriched drinks and the reference drink in the evaluated sensory parameters. Brix test showed that the percentage of sugars increased with increasing fiber content. The conclusion of the study is that adding resistant maltodextrin to ProViva Mango doesn’t affect the physiological properties of ProViva. To obtain the same nutritional value as a standard ProViva Mango, the amount added sugar needs to be adjusted so that the amount of total sugars remain at the same level as the standard.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2005. / Thesis documentation sheet inserted. Appendix reprints four papers and manuscripts co-authored with others. Includes bibliographical references. Also partially issued electronically via World Wide Web in PDF format; online version lacks appendix.

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xvi, 231 p.; also includes graphics (some col.) Includes bibliographical references (p. 212-224). Available online via OhioLINK's ETD Center