4 results on '"Molbak, L."'
Search Results
2. Elective cesarean delivery affects gut maturation and delays microbial colonization but does not increase necrotizing enterocolitis in preterm pigs
- Author
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Siggers, R.H., Thymann, T., Jensen, B.B., Molbak, L., Heegaard, P.M.H., Schmidt, M., Buddington, R.K., and Sangild, P.T.
- Subjects
Cesarean section -- Physiological aspects ,Intestines -- Properties ,Microbial colonies -- Properties ,Enterocolitis, Neonatal necrotizing -- Physiological aspects ,Enterocolitis, Pseudomembranous -- Physiological aspects ,Swine -- Physiological aspects ,Swine -- Diseases ,Intestines -- Microbiology ,Intestines -- Research ,Biological sciences - Abstract
Although preterm birth and formula feeding increase the risk of necrotizing enterocolitis (NEC), the influences of cesarean section (CS) and vaginal delivery (VD) are unknown. Therefore, gut characteristics and NEC incidence and severity were evaluated in preterm pigs (92% gestation) delivered by CS or VD. An initial study showed that newborn CS pigs (n = 6) had decreased gastric acid secretion, absorption of intact proteins, activity of brush-border enzymes and pancreatic hydrolases, plasma cortisol, rectal temperature, and changes in blood chemistry, indicating impaired respiratory function, compared with VD littermates (n = 6). In a second experiment, preterm CS (n = 16) and VD (n = 16) pigs were given total parenteral nutrition (36 h) then fed porcine colostrum (VD-COL, n = 6; CS-COL, n = 6) or infant milk formula (VD-FORM, n = 10; CS-FORM, n = 10) for 2 days. Across delivery, FORM pigs showed significantly higher NEC incidence, tissue proinflammatory cytokines (IFN-7 and IL-6), Clostridium colonization, and impaired intestinal function, compared with COL pigs. NEC incidence was equal for CS (6/16) and VD (6/16) pigs, CS pigs had decreased bacterial diversity and density, higher villus heights, and increased brush-border enzyme activities (lactase, aminopeptidases) compared with VD pigs. In particular, VD-FORM pigs showed reduced mucosal proportions, reduced lactase and aminopeptidases, and increased proinflammatory cytokine IL-6 compared with CS-FORM (P < 0.06). Despite the initial improvement of intestinal and metabolic functions following VD, gut function, and inflammation were similar, or more negatively affected in VD neonates than CS neonates. Both delivery modes exhibited positive and negative influences on the preterm gut, which may explain the similar NEC incidence. vaginal; cesarean section; bacteria; birth; intestine
- Published
- 2008
3. The effect of a diet with fructan-rich chicory roots on intestinal helminths and microbiota with special focus on Bifidobacteria and Campylobacter in piglets around weaning
- Author
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Jensen, A. N., Mejer, H., Molbak, L., Langkjaer, M., Jensen, T. K., Angen, Øystein, Martinussen, T., Klitgaard, K., Baggesen, D. L., Thamsborg, S. M., Roepstorff, Andreas, and Roepstorff, A.
- Subjects
medicine.medical_treatment ,Ileum ,medicine.disease_cause ,SF1-1100 ,Microbiology ,Animal science ,fluids and secretions ,medicine ,Helminths ,Weaning ,Trichuris suis ,Ascaris suum ,Bifidobacterium ,biology ,Prebiotic ,Campylobacter ,weaning ,Lachnospiraceae ,chicory ,biology.organism_classification ,Animal culture ,medicine.anatomical_structure ,Animal Science and Zoology - Abstract
The restrictions on the use of antibiotic and anthelmintic treatments in organic pig farming necessitate alternative non-medical control strategies. Therefore, the antibiotic and parasite-reducing effect of a fructan-rich (prebiotic) diet of dried chicory was investigated in free-ranging piglets. Approximately half of 67 piglets from nine litters were experimentally infected with Ascaris suum and Trichuris suis in the suckling period (1 to 7 weeks of age) and 58 of the piglets were challenged daily with Eschericia coli O138:F8 for 9 days after weaning to induce weaning diarrhoea. The litters were fed either chicory (30% dry matter) or a control diet. The effect of chicory on intestinal helminths, intestinal microbiota, especially Bifidobacteria and Campylobacter spp. and E. coli post-weaning diarrhoea was assessed. The weight gain of the piglets was not impaired significantly by chicory. The intestinal A. suum worm burden was reduced by 64% (P = 0.034) in the chicory-fed piglets, whereas these same piglets had 63% more T. suis worms (P = 0.016). Feeding with chicory elicited no changes among the main bacterial groups in ileum according to terminal restriction fragment length polymorphism analysis. However, the terminal-restriction fragment (T-RF) 208 bp, which may belong to Lachnospiraceae, was stimulated by the chicory feed (P = 0.03), and T-RF 370 bp that matches Enterobacter belonging to the Enterobacteria was reduced (P = 0.004). In addition, chicory increased the level of Bifidobacteria (P = 0.001) and the faecal Campylobacter excretion level was transitorily reduced in chicory-fed piglets at 7 weeks of age (P = 0.029). Unfortunately, it was not possible to assess the effect of chicory on post-weaning diarrhoea as it did not develop. In conclusion, feeding piglets chicory around the time of weaning caused complex changes of the microbiota and parasite communities within the intestinal tract, and feeding piglets chicory may therefore serve as an animal-friendly strategy to control pathogens.
- Published
- 2011
4. Simultaneous monitoring of cell number and metabolic activity of specific bacterial populations with a dual gfp-luxAB marker system.
- Author
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Unge A, Tombolini R, Molbak L, and Jansson JK
- Subjects
- Colony Count, Microbial, Electroporation, Escherichia coli genetics, Escherichia coli growth & development, Escherichia coli metabolism, Flow Cytometry, Fluorescence, Green Fluorescent Proteins, Luminescent Proteins metabolism, Plasmids, Pseudomonas fluorescens genetics, Pseudomonas fluorescens growth & development, Pseudomonas fluorescens metabolism, Biomarkers, Environmental Monitoring, Luciferases genetics, Luciferases metabolism, Luminescent Proteins genetics, Soil Microbiology
- Abstract
A dual marker system was developed for simultaneous quantification of bacterial cell numbers and their activity with the luxAB and gfp genes, encoding bacterial luciferase and green fluorescent protein (GFP), respectively. The bioluminescence phenotype of the luxAB biomarker is dependent on cellular energy status. Since cellular metabolism requires energy, bioluminescence output is directly related to the metabolic activity of the cells. By contrast, GFP fluorescence has no energy requirement. Therefore, by combining these two biomarkers, total cell number and metabolic activity of a specific marked cell population could be monitored simultaneously. Two different bacterial strains, Escherichia coli DH5alpha and Pseudomonas fluorescens SBW25, were chromosomally tagged with the dual marker cassette, and the cells were monitored under different conditions by flow cytometry, plate counting, and luminometry. During log-phase growth, the luciferase activity was proportional to the number of GFP-fluorescent cells and culturable cells. Upon entrance into stationary phase or during starvation, luciferase activity decreased due to a decrease in cellular metabolic activity of the population, but the number of GFP-fluorescing cells and culturable cells remained relatively stable. In addition, we optimized a procedure for extraction of bacterial cells from soil, allowing GFP-tagged bacteria in soil samples to be quantitated by flow cytometry. After 30 days of incubation of P. fluorescens SBW25::gfp/lux in soil, the cells were still maintained at high population densities, as determined by GFP fluorescence, but there was a slow decline in luciferase activity, implicating nutrient limitation. In conclusion, the dual marker system allowed simultaneous monitoring of the metabolic activity and cell number of a specific bacterial population and is a promising tool for monitoring of specific bacteria in situ in environmental samples.
- Published
- 1999
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