10 research outputs found
Exploring Metabolic Pathway Reconstruction and Genome-Wide Expression Profiling in Lactobacillus reuteri to Define Functional Probiotic Features
The genomes of four Lactobacillus reuteri strains isolated from human breast milk and the gastrointestinal tract have been recently sequenced as part of the Human Microbiome Project. Preliminary genome comparisons suggested that these strains belong to two different clades, previously shown to differ with respect to antimicrobial production, biofilm formation, and immunomodulation. To explain possible mechanisms of survival in the host and probiosis, we completed a detailed genomic comparison of two breast milk–derived isolates representative of each group: an established probiotic strain (L. reuteri ATCC 55730) and a strain with promising probiotic features (L. reuteri ATCC PTA 6475). Transcriptomes of L. reuteri strains in different growth phases were monitored using strain-specific microarrays, and compared using a pan-metabolic model representing all known metabolic reactions present in these strains. Both strains contained candidate genes involved in the survival and persistence in the gut such as mucus-binding proteins and enzymes scavenging reactive oxygen species. A large operon predicted to encode the synthesis of an exopolysaccharide was identified in strain 55730. Both strains were predicted to produce health-promoting factors, including antimicrobial agents and vitamins (folate, vitamin B12). Additionally, a complete pathway for thiamine biosynthesis was predicted in strain 55730 for the first time in this species. Candidate genes responsible for immunomodulatory properties of each strain were identified by transcriptomic comparisons. The production of bioactive metabolites by human-derived probiotics may be predicted using metabolic modeling and transcriptomics. Such strategies may facilitate selection and optimization of probiotics for health promotion, disease prevention and amelioration
Role of 5-HT 1A receptors in antidepressant-like effect of dichloromethane fraction of Kielmeyera coriacea in rats subjected to the forced swim test
Objective : We examined the involvement of 5-HT neurotransmission on
the antidepressant-like effect of the dichloromethane (DcM) fraction of
an extract from Kielmeyera coriacea stems. Materials and Methods :
Male Wistar rats treated chronically (45 days, gavage) with the DcM
fraction received an intradorsal raphe nucleus (DRN) microinjection of
saline or 5-HT 1A receptor ligands and were evaluated in the forced
swimming test (FST) and in the open-field test (OFT). Results : The
DcM fraction (5.0 mg/kg) reduced immobility time in the FST without
altering locomotion in the OFT. IntraDRN microinjection of the 5-HT 1A
receptor agonist, (+)-8-OH-DPAT (0.10; 0.20 or 0.33 μg) increased
immobility time and reduced locomotion at the higher dose whereas the
5-HT1A antagonists, (-)-pindolol (0.10; 0.20 or 0.40 μg) or
WAY100635 (0.11; 0.22 or 0.43 μg) did not produce any effect in
the behavioral tests. IntraDRN (+)-8-OH-DPAT (0.20 or 0.33 μg) in
rats treated with the DcM fraction (5.0 mg/kg) blocked the changes in
the immobility time or in locomotion produced by each drug. Intra-DRN
(-)-pindolol (0.10 μg) or WAY100635 (0.43 μg) in rats treated
with a subactive dose of the DcM fraction (4.0 mg/kg) synergistically
reduced immobility time in the FST. Conclusion : The DcM fraction of
Kielmeyera coriacea produced an antidepressant-like effect in the FST
and interacted with 5-HT 1A receptor ligands. Activation of 5-HT 1A
receptors into DRN by (+) 8-OH-DPAT produced detectable changes in the
FST or in the OFT
1-Oleoyl Lysophosphatidic Acid: A New Mediator of Emotional Behavior in Rats
The role of lysophosphatidic acid (LPA) in the control of emotional behavior remains to be determined. We analyzed the effects of the central administration of 1-oleoyl-LPA (LPA 18∶1) in rats tested for food consumption and anxiety-like and depression-like behaviors. For this purpose, the elevated plus-maze, open field, Y maze, forced swimming and food intake tests were performed. In addition, c-Fos expression in the dorsal periaqueductal gray matter (DPAG) was also determined. The results revealed that the administration of LPA 18∶1 reduced the time in the open arms of the elevated plus-maze and induced hypolocomotion in the open field, suggesting an anxiogenic-like phenotype. Interestingly, these effects were present following LPA 18∶1 infusion under conditions of novelty but not under habituation conditions. In the forced swimming test, the administration of LPA 18∶1 dose-dependently increased depression-like behavior, as evaluated according to immobility time. LPA treatment induced no effects on feeding. However, the immunohistochemical analysis revealed that LPA 18∶1 increased c-Fos expression in the DPAG. The abundant expression of the LPA(1) receptor, one of the main targets for LPA 18∶1, was detected in this brain area, which participates in the control of emotional behavior, using immunocytochemistry. These findings indicate that LPA is a relevant transmitter potentially involved in normal and pathological emotional responses, including anxiety and depression