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- Linninge, Caroline, et al.
(författare)
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Pre-treatment with antibiotics and Escherichia coli to equalize the gut microbiota in conventional mice.
- 2015
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Ingår i: Antonie van Leeuwenhoek. - : Springer Science and Business Media LLC. - 1572-9699 .- 0003-6072. ; 107:1, s. 149-156
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Tidskriftsartikel (refereegranskat)abstract
- The composition of the gut microbiota can vary widely between individual mice of the same batch and thereby affect the resulting outcome in experimental studies. Therefore, an efficient method is needed to equalize the gut microbiota prior to the start of critical experiments. In order to minimize variations in gut microbiota between animals and provide the animals with a Gram-negative flora exposing lipopolysaccharides in the cell-walls, C57BL/6 mice were given a mixture of ampicillin, metronidazole and clindamycin in the drinking water for 3 days and then Escherichia coli for two additional days. Treatment with antibiotics alone or with antibiotics in combination with E. coli was well tolerated by all animals. Body weight and liver weight were not affected, although higher hepatic fat content was found in treated animals (p < 0.05). The diversity of the gut microbiota was strongly reduced in animals treated with antibiotics and antibiotics in combination with E. coli (p < 0.01), without affecting the total amount of bacteria. Cloned and sequenced 16S rRNA genes showed high presence of Enterobacteriaceae and Porphymonadaceae in the treated animals. Analysis with Principal Component Analysis gave a clear separation of the composition in microbiota between different treatment groups. The described treatment efficiently equalized the gut microbiota and provided the animals with a strong abundance of Enterobacteriaceae without changing the total load of bacteria. This is a straightforward, lenient and efficient method of pre-treatment to equalize the gut microbiota of mice as a starting procedure of animal studies.
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| 2. |
- Linninge, Caroline
(författare)
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The Gut Bacterial Flora - Focus on Early Life and Physiological Traits
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The gastrointestinal tract of the foetus is considered sterile but during vaginal birth the neonate comes into contact with bacteria from the maternal vaginal and intestinal microbiota. The main focus of this doctoral thesis was to elucidate the initial bacterial ecosystem in newborns and to relate microbial perturbations to physiological traits. The bacterial flora was mainly studied with molecular-genetic methods. When the microbiota was assessed in one-week-old infants, reduced faecal bacterial diversity was found in infants developing atopic eczema at the age of 18 months compared to those infants not developing eczema. To further elucidate the pioneer microbiota, stool samples from healthy full-term vaginally-born neonates was studied. Lactobacillus was found in all newborns within 48 hours after birth. Species commonly found in the vaginal microbiota were to some extent detected among the babies. Other bacterial groups were found in varying prevalence. Interestingly, a subgroup of neonates born large for gestational age had significantly more Proteobacteria compared to neonates born appropriate for gestational age. Maternal microbiota and dietary habits are known to impact offspring physiology. Results presented in this thesis show impaired physiology in suckling rat pups to dams of the outbred Sprague-Dawley stock when these were treated with high-energy dense diet during the gestation and lactation period. Offspring body weight, adiposity, gut permeability and systemic inflammation were further accentuated if the Gram-negative Escherichia coli was given to the dams in combination with the high-energy dense feed. In a similar experimental design, the pups were monitored in a longitudinal study. E. coli exposure from foetal life until six months of age decreased the diversity of the caecal microbiota along with enhanced adiposity. In contrast, when the Gram-positive Lactobacillus plantarum was given instead of E. coli, body weight gain and fat accumulation were lower in addition to a more favourable gut microbiota, implying the prospect of effect on health homeostasis by bacterial consumption. This thesis suggests that a high load of E. coli should be avoided in pregnant mothers and in children, and treatment with L. plantarum may be a therapeutic option. However, more extensive research is needed to establish the relationship between inflammation, obesity and the bacterial flora of the gut. A general conclusion concerning the microbiota is that the intestinal ecosystem should be studied at least at the hierarchical level of genus or family, but preferably on the species level since looking at the phylum level can give superficial information.
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