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Mitochondrial dysfunction is a hypothesized component in the multifactorial pathogenesis of migraine without aura (MoA, 'common migraine') and the related condition of cyclic vomiting syndrome (CVS). In this study, the entire mitochondrial genome was sequenced in 20 haplogroup-H CVS patients, a subject group studied because of greater genotypic and phenotypic homogeneity. Sequences were compared against haplogroup-H controls. Polymorphisms of interest were tested in 10 additional CVS subjects and in 112 haplogroup-H adults with MoA. The 16519C-->T polymorphism was found to be highly disease associated: 21/30 CVS subjects [70%, odds ratio (OR) 6.2] and 58/112 migraineurs (52%, OR 3.6) vs. 63/231 controls (27%). A second polymorphism, 3010G-->A, was found to be highly disease associated in those subjects with 16519T: 6/21 CVS subjects (29%, OR 17) and 15/58 migraineurs (26%, OR 15) vs. 1/63 controls (1.6%). Our data suggest that these polymorphisms constitute a substantial proportion of the genetic factor in migraine pathogenesis, and strengthen the hypothesis that there is a component of mitochondrial dysfunction in migraine.

The mechanisms and the functional importance of G-protein-coupled receptor dimerization are poorly understood. We therefore analyzed dimerization of the bradykinin B 2 receptor. The binding of the agonist bradykinin to the B 2 receptor endogenously expressed on PC-12 cells led to the formation of receptor dimers, whereas the B 2 antagonist HOE140 did not induce dimerization, suggesting that B 2 receptor dimerization was linked to receptor activation. Addition of a peptide corresponding to the amino terminus of the receptor reduced the amount of detected B 2 receptor dimers, whereas peptides derived from the extracellular loops had The mechanism and the function of agonist-induced receptor dimerization of G-protein-coupled receptors is still a matter of debate. For a variety of G-protein-coupled receptors, receptor dimers have been detected recently, e.g. for the ␤ 2 -adrenergic receptor (1), the dopamine D 2 receptor (2), the metabotropic glutamate receptor 5 (3), or the calcium sensing receptor (4). G-protein-coupled receptors seem to dimerize via two different mechanisms. Whereas dimerization of the dopamine D 2 and the ␤ 2 -adrenergic receptor occurs via transmembrane regions, the metabotropic glutamate receptor and the calcium sensing receptor dimerize via their large amino terminus and, to a lesser extent, via their transmembrane regions (1-4). G-protein-coupled receptors are classified into three main families according to the structure and length of their amino terminus and the localization of the agonist binding site (5). The metabotropic glutamate receptor and the calcium sensing receptor are members of family 3 receptors. In family 3 receptors, the amino terminus is not only involved in dimerization but also essential for agonist binding. In contrast, adrenaline and dopamine, which are agonists on family 1 receptors, bind within the seven transmembrane helices (5). The transmembrane regions are also involved in dimerization of these receptors (1, 2). Thus, the mechanism of receptor dimerization seems to be related to agonist binding. To further investigate this hypothesis, we analyzed dimerization of the bradykinin B 2 receptor. The B 2 receptor belongs also to family 1. However, receptors for catecholamines or dopamine belong to the 1a subfamily, whereas receptors for peptides like bradykinin are classified into the subfamily 1b (5). In contrast to family 1a receptors, 1b-type receptors are characterized by an agonist binding site within the amino terminus of the receptor and the extracellular loops (5). In accordance with its classification as a family 1b receptor, a binding site(s) for the agonist bradykinin was identified within the extracellular loop regions, e.g. the connecting loops between membrane domains IV and V and domains VI and VII (6 -9). Because the agonist binding site of 1b receptors differs from that of 1a family receptors, we asked whether the sites necessary for receptor dimerization were also different between members of these two subfamilies. Here, we report that binding of brady...

Pediatric cyclic vomiting syndrome (CVS) is associated with a high prevalence of co-morbid migraine and other functional disorders, and with two adult migraine-associated mitochondrial DNA (mtDNA) polymorphisms: 16519T and 3010A. These potential associations have not been studied in adult CVS. The objective of this study is to determine the prevalence of 16519T and 3010A mtDNA polymorphisms and other functional disorders in adult CVS patients. Adults with CVS recruited from the University of Kansas meeting Rome III criteria and a population control group completed a self-reported survey that included questions relating to the diagnostic criteria for several functional disorders. DNA was isolated from blood or saliva and genotyping was performed by standard methodologies. Adult CVS subjects, compared to controls, had significantly more symptoms consistent with several other functional disorders. 16519T was present in 22/31 cases (71%) of child-onset (<12 years) and 9/31 (29%) cases of adult-onset (18+ years) CVS (P = 0.01), vs 27% of controls. Among subjects with 16519T, 3010A was present in 30% of child-onset vs 0% of adult-onset CVS (P = 0.05) and 2% of controls. The conclusions drawn were: (i) unlike pediatric CVS, adult CVS is not associated with the 16519T and 3010A mtDNA polymorphisms, suggesting a degree of genetic distinction and (ii) similar to the pediatric setting, adult CVS is associated with a substantial burden of co-morbid functional disorders.

Twelve selected phenol-degrading bacterial isolates were obtained on phenol agar plates using culture enrichment technique. Molecular identification of the isolates was performed using eubacterial 16S rRNA PCR specific primers. Based on 16S rDNA sequence analysis, the results revealed that the majority of the isolates (8 out of 12) are affiliated to the g-subdivision of Proteobacteria. Four out of the eight isolates are closely related to the genus Acinetobacter. Molecular heterogeneity among the phenol-degrading isolates was further investigated by using rep-PCR chromosomal fingerprinting and correlated with plasmid and antibiotic profile analysis. Rep-PCR results strongly confirmed that the bacterial isolates from different environmental sites produced different fingerprinting patterns. The mineralization of phenol by all isolates was evaluated using 14C-labeled phenol assay. Phenol mineralization ranged from 55% (W-17) to 0.4% (Sea-9). This was further confirmed by the detection of several monoaromatic and polyaromatic degrading genes, e.g., pheA, MopR, XylE, and NahA. In addition, catalytic enzymes such as catalase and dioxygenase were also monitored.