Compartmentation of glutamate metabolism in brain. Evidence for the existence of two different tricarboxylic acid cycles in brain

1. (14)C from [1-(14)C]glucose injected intraperitoneally into mice is incorporated into glutamate, aspartate and glutamine in the brain to a much greater extent than (14)C from [2-(14)C]glucose. This difference for [1-(14)C]glucose and [2-(14)C]glucose increases with time. The amount of (14)C in C-1 of glutamate increases steadily with time with both precursors. It is suggested that a large part of the glutamate and aspartate pools in brain are in close contact with intermediates of a fast-turning tricarboxylic acid cycle. 2. (14)C from [1-(14)C]acetate and [2-(14)C]acetate is incorporated to a much larger extent into glutamine than into glutamate. An examination of the time-course of (14)C incorporated into glutamine and glutamate reveals that glutamine is not formed from the glutamate pool, labelled extensively by glucose, but from a small glutamate pool. This small glutamate pool is not derived from an intermediate of a fast-turning tricarboxylic acid cycle. 3. It is proposed that two different tricarboxylic acid cycles exist in brain.     

Molecular imaging of amyloid beta peptides in mouse brain sections using mass spectrometry

In this paper, a reverse-phase high-performance liquid chromatographic method using a chemically modified electrode coupled with microdialysis was developed to study the effect of electromagnetic impulse (EMI) on monoamine neurotransmitter metabolism in nerve cells. To detect the monoamines and their metabolites, a poly (para-aminobenzoic acid) (P-pABA)-modified electrode was prepared. The modified electrode exhibited efficiently electrocatalytic oxidation for monoamines and their metabolites with relatively high sensitivity, stability, and long life. Nerve cells were primarily cultured. EMI was radiated to three experimental model nerve cells: (i) on mature nerve cells, (ii) on the culture medium, and (iii) on juvenile nerve cells for various periods of time. Then the levels of monoamines in the culture medium were detected by high-performance liquid chromatography-electrochemical detection. The data indicated that electromagnetic fields could influence neurotransmitter metabolism by direct effect on nerve cells or effect on the nutrient medium and that the effect was not only relevant with the length of radiation time, but also with the growing state of the nerve cells.     

Endophilin is required for synaptic vesicle endocytosis by localizing synaptojanin

Endophilin is a membrane-associated protein required for endocytosis of synaptic vesicles. Two models have been proposed for endophilin: that it alters lipid composition in order to shape membranes during endocytosis, or that it binds the polyphosphoinositide phosphatase synaptojanin and recruits this phosphatase to membranes. In this study, we demonstrate that the unc-57 gene encodes the Caenorhabditis elegans ortholog of endophilin A. We demonstrate that endophilin is required in C. elegans for synaptic vesicle recycling. Furthermore, the defects observed in endophilin mutants closely resemble those observed in synaptojanin mutants. The electrophysiological phenotype of endophilin and synaptojanin double mutants are virtually identical to the single mutants, demonstrating that endophilin and synaptojanin function in the same pathway. Finally, endophilin is required to stabilize expression of synaptojanin at the synapse. These data suggest that endophilin is an adaptor protein required to localize and stabilize synaptojanin at membranes during synaptic vesicle recycling.     

<Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> inhibits <Emphasis Type="Italic">in-vitro Candida</Emphasis> biofilm development

Background  

Elucidation of the communal behavior of microbes in mixed species biofilms may have a major impact on understanding infectious diseases and for the therapeutics. Although, the structure and the properties of monospecies biofilms and their role in disease have been extensively studied during the last decade, the interactions within mixed biofilms consisting of bacteria and fungi such as Candida spp. have not been illustrated in depth. Hence, the aim of this study was to evaluate the interspecies interactions of Pseudomonas aeruginosa and six different species of Candida comprising C. albicans, C. glabrata, C. krusei, C. tropicalis, C. parapsilosis, and C. dubliniensis in dual species biofilm development.     

Association of 25-Hydroxyvitamin D status and genetic variation in the vitamin D metabolic pathway with FEV1 in the Framingham Heart Study

Background

Vitamin D is associated with lung function in cross-sectional studies, and vitamin D inadequacy is hypothesized to play a role in the pathogenesis of chronic obstructive pulmonary disease. Further data are needed to clarify the relation between vitamin D status, genetic variation in vitamin D metabolic genes, and cross-sectional and longitudinal changes in lung function in healthy adults.

Methods

We estimated the association between serum 25-hydroxyvitamin D [25(OH)D] and cross-sectional forced expiratory volume in the first second (FEV₁) in Framingham Heart Study (FHS) Offspring and Third Generation participants and the association between serum 25(OH)D and longitudinal change in FEV₁ in Third Generation participants using linear mixed-effects models. Using a gene-based approach, we investigated the association between 241 SNPs in 6 select vitamin D metabolic genes in relation to longitudinal change in FEV₁ in Offspring participants and pursued replication of these findings in a meta-analyzed set of 4 independent cohorts.

Results

We found a positive cross-sectional association between 25(OH)D and FEV₁ in FHS Offspring and Third Generation participants (P = 0.004). There was little or no association between 25(OH)D and longitudinal change in FEV₁ in Third Generation participants (P = 0.97). In Offspring participants, the CYP2R1 gene, hypothesized to influence usual serum 25(OH)D status, was associated with longitudinal change in FEV₁ (gene-based P < 0.05). The most significantly associated SNP from CYP2R1 had a consistent direction of association with FEV₁ in the meta-analyzed set of replication cohorts, but the association did not reach statistical significance thresholds (P = 0.09).

Conclusions

Serum 25(OH)D status was associated with cross-sectional FEV₁, but not longitudinal change in FEV₁. The inconsistent associations may be driven by differences in the groups studied. CYP2R1 demonstrated a gene-based association with longitudinal change in FEV₁ and is a promising candidate gene for further studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0238-y) contains supplementary material, which is available to authorized users.