Conserved dimeric subunit stoichiometry of SLC26 multifunctional anion exchangers

The SLC26 gene family encodes multifunctional transport proteins in numerous tissues and organs. Some paralogs function as anion exchangers, others as anion channels, and one, prestin (SLC26A5), represents a membrane-bound motor protein in outer hair cells of the inner ear. At present, little is known about the molecular basis of this functional diversity. We studied the subunit stoichiometry of one bacterial, one teleost, and two mammalian SLC26 isoforms expressed in Xenopus laevis oocytes or in mammalian cells using blue native PAGE and chemical cross-linking. All tested SLC26s are assembled as dimers composed of two identical subunits. Co-expression of two mutant prestins with distinct voltage-dependent capacitances results in motor proteins with novel electrical properties, indicating that the two subunits do not function independently. Our results indicate that an evolutionarily conserved dimeric quaternary structure represents the native and functional state of SLC26 transporters.     

Genetic mapping of glutaric aciduria, type 3, to chromosome 7 and identification of mutations in c7orf10

While screening Old Order Amish children for glutaric aciduria type 1 (GA1) between 1989 and 1993, we found three healthy children who excreted abnormal quantities of glutaric acid but low 3-hydroxyglutaric acid, a pattern consistent with glutaric aciduria type 3 (GA3). None of these children had the GCDH c.1262C→T mutation that causes GA1 among the Amish. Using single-nucleotide polymorphism (SNP) genotypes, we identified a shared homozygous 4.7 Mb region on chromosome 7. This region contained 25 genes including C7orf10, an open reading frame with a putative mitochondrial targeting sequence and coenzyme-A transferase domain. Direct sequencing of C7orf10 revealed that the three Amish individuals were homozygous for a nonsynonymous sequence variant (c.895C→T, Arg299Trp). We then sequenced three non-Amish children with GA3 and discovered two nonsense mutations (c.322C→T, Arg108Ter, and c.424C→T, Arg142Ter) in addition to the Amish mutation. Two pathogenic alleles were identified in each of the six patients. There was no consistent clinical phenotype associated with GA3. In affected individuals, urine molar ratios of glutarate to its derivatives (3-hydroxyglutarate, glutarylcarnitine, and glutarylglycine) were elevated, suggesting impaired formation of glutaryl-CoA. These observations refine our understanding of the lysine-tryptophan degradation pathway and have important implications for the pathophysiology of GA1.     

Synthesis and structure of [bis(pyrazol-1-yl)acetato]trioxorhenium(VII) and [bis(3,5-dimethylpyrazol-1-yl)acetato]trioxorhenium(VII)

The coordination of the ligands bis(pyrazol-1-yl)acetate (bpza) and bis(3,5-dimethylpyrazol-1-yl)acetate (bdmpza) to rhenium(VII) was investigated. The compounds [(bpza)ReO₃] and [(bdmpza)ReO₃] were synthesised by reaction of bpza and bdmpza with perrhenic acid with the loss of one water molecule. The new complex [(bdmpza)ReO₃] was characterised by single-crystal X-ray analysis. It has a monomeric structure with a distorted octahedron for the [N,N,O]ReO₃ central core.     

The uptake of dental services by elderly Germans

Objective: The aim of the study was to assess the uptake of dental services by the old and very old population within the scope of the Berlin Aging Study (Berliner Altersstudie BASE ). Design: A multi‐disciplinary structured interview was performed on 928 subjects, aged from 70 to 103 years of whom 516 persons volunteered to take part in a 14‐session intensive protocol. Six representative study groups were matched for age and gender. Subjects were asked to recall the timing of their most recent dental visit. Data were validated by sending for dental records and compared with all study participants from the multi‐disciplinary intake assessment. Data were related to age group, dental state, dementia and education. Results: Reported last contact with dental services ranged from 2 weeks to 52 years (median 18 months) with a higher time lapse in the study groups aged 85 and older. Dentate subjects had seen their dentist more recently than edentate subjects. Higher education correlated with an increased dental utilisation. Subjective memory on the time lapse since the last dental appointment coincided in 13% of the subjects with available dental records (n=84), was misjudged between one and six months in 55%, and by more than six months in the remainder. Moderately or severely demented subjects who remembered their last dental appointment (n=48 of 70) showed no consistently different utilisation to healthy or mildly demented studs participants. Conclusion: Edentate old and very old subjects show the least frequent utilisation of dental services. Data on motivation and barriers to care are needed to develop strategies to improve the use of dental services and thus promote oral health in late life.     

Molecular evolution of human T-cell leukemia virus

Summary In light of previous data, which suggested thatAc-like sequences might have undergone a significant radiation in the recent past, I examined the copy number ofAc-like sequences in representatives of all theZea taxa, both maize and teosinte. The maize and teosinte samples contained approximately equal numbers ofAc-like sequences. FewAc-like sequences were in unmethylated regions of DNA. Unmethylated elements were distributed randomly among both maize and teosinte lines. The appearance in a line of a discrete band resulting from digestion with one methylation-sensitive restriction enzyme was correlated with the appearance of discrete bands with other methylation-sensitive bands. This suggests that individualAc-like elements are occasionally demethylated in many sites. No unmethylated element having restriction fragments of the lengths predicted from the publishedAc sequence was seen in the approximately 326 elements examined.     

Vitamin D deficiency is associated with higher disease activity and the risk for uveitis in juvenile idiopathic arthritis - data from a German inception cohort

Objective

The objective was to evaluate the 25(OH) vitamin D (25(OH)D) status of patients with juvenile idiopathic arthritis (JIA) and determine whether the 25(OH)D level is associated with disease activity and the course of JIA.

Methods

Patients ≤?16?years of age with recently diagnosed JIA (<?12?months) were enrolled in the inception cohort of patients with newly diagnosed JIA (ICON), an ongoing prospective observational, controlled multicenter study started in 2010. Clinical and laboratory parameters were ascertained quarterly during the first year and half-yearly thereafter.Of the 954 enrolled patients, 360 patients with two blood samples taken during the first 2?years after inclusion and with follow up of 3?years were selected. The serum 25(OH)D levels were determined and compared with those of subjects from the general population after matching for age, sex, migration status and the month of blood-drawing.

Results

Nearly half of the patients had a deficient 25(OH)D level (<?20?ng/ml) in the first serum sample and a quarter had a deficient level in both samples. Disease activity and the risk of developing JIA-associated uveitis were inversely correlated with the 25(OH)D level (β?=???0.20, 95% CI ??0.37; 0.03, hazard ratio 0.95, 95% CI 0.91; 0.99, respectively).

Conclusion

In this study, 25(OH)D deficiency was common and associated with higher disease activity and risk of developing JIA-associated uveitis. Further studies are needed to substantiate these results and determine whether correcting 25(OH)D deficiency is beneficial in JIA.

     

On the presence and localization of glycogen accumulations inside coronet cells of the saccus vasculosus of the dogfish (Scylliorhinus caniculus)

Summary In several coronet cells of the saccus vasculosus of Scylliorhinus large quantities of glycogen occur, as shown by light and electron microscopy. The significance of glycogen as an energy storage necessary for a transcellular ion transport process taking place in the coronet cells is discussed.The authors thank Dr. F.C.G. van de Veerdonk, W. F. Jansen and W. F. G. Flight for reading the manuscipt and for their critical remarks. They are also indebted to Mr. H. van Kooten and his staff for their valuable photographic assistance.