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- Fallani, M, et al.
(författare)
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Determinants of the human infant intestinal microbiota after the introduction of first complementary foods in infant samples from five European centres
- 2011
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Ingår i: Microbiology (Reading, England). - : Microbiology Society. - 1465-2080 .- 1350-0872. ; 157:Pt 5, s. 1385-1392
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Tidskriftsartikel (refereegranskat)abstract
- Although it is well established that early infant feeding has a major influence on the establishment of the gut microbiota, very little is understood about how the introduction of first solid food influences the colonization process. This study aimed to determine the impact of weaning on the faecal microbiota composition of infants from five European countries (Sweden, Scotland, Germany, Italy and Spain) which have different lifestyle characteristics and infant feeding practices. Faecal samples were collected from 605 infants approximately 4 weeks after the introduction of first solid foods and the results were compared with the same infants before weaning (6 weeks of age) to investigate the association with determining factors such as geographical origin, mode of delivery, previous feeding method and age of weaning. Samples were analysed by fluorescence in situ hybridization and flow cytometry using a panel of 10 rRNA targeted group- and species-specific oligonucleotide probes. The genus Bifidobacterium (36.5 % average proportion of total detectable bacteria), Clostridium coccoides group (14 %) and Bacteroides (13.6 %) were predominant after weaning. Similar to pre-weaning, northern European countries were associated with a higher proportion of bifidobacteria in the infant gut microbiota while higher levels of Bacteroides and lactobacilli characterized southern European countries. As before weaning, the initial feeding method influenced the Clostridium leptum group and Clostridium difficile+Clostridium perfringens species, and bifidobacteria still dominated the faeces of initially breast-fed infants. Formula-fed babies presented significantly higher proportions of Bacteroides and the C. coccoides group. The mode of birth influenced changes in the proportions of bacteroides and atopobium. Although there were significant differences in the mean weaning age between countries, this was not related to the populations of bifidobacteria or bacteroides. Thus, although the faecal microbiota of infants after first complementary foods was different to that before weaning commenced, many of the initial influences on microbiota composition were still evident.
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- Vellosillo, T, et al.
(författare)
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Defense activated by 9-lipoxygenase-derived oxylipins requires specific mitochondrial proteins
- 2013
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Ingår i: Plant physiology. - : Oxford University Press (OUP). - 1532-2548. ; 161:2, s. 617-627
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Tidskriftsartikel (refereegranskat)abstract
- 9-Lipoxygenases (9-LOXs) initiate fatty acid oxygenation, resulting in the formation of oxylipins activating plant defense against hemibiotrophic pathogenic bacteria. Previous studies using nonresponding to oxylipins (noxy), a series of Arabidopsis (Arabidopsis thaliana) mutants insensitive to the 9-LOX product 9-hydroxy-10,12,15-octadecatrienoic acid (9-HOT), have demonstrated the importance of cell wall modifications as a component of 9-LOX-induced defense. Here, we show that a majority (71%) of 41 studied noxy mutants have an added insensitivity to isoxaben, an herbicide inhibiting cellulose synthesis and altering the cell wall. The specific mutants noxy2, noxy15, and noxy38, insensitive to both 9-HOT and isoxaben, displayed enhanced susceptibility to Pseudomonas syringae DC3000 as well as reduced activation of salicylic acid-responding genes. Map-based cloning identified the mutation in noxy2 as At5g11630 encoding an uncharacterized mitochondrial protein, designated NOXY2. Moreover, noxy15 and noxy38 were mapped at the DYNAMIN RELATED PROTEIN3A and FRIENDLY MITOCHONDRIA loci, respectively. Fluorescence microscopy and molecular analyses revealed that the three noxy mutants characterized exhibit mitochondrial dysfunction and that 9-HOT added to wild-type Arabidopsis causes mitochondrial aggregation and loss of mitochondrial membrane potential. The results suggest that the defensive responses and cell wall modifications caused by 9-HOT are under mitochondrial retrograde control and that mitochondria play a fundamental role in innate immunity signaling.
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