Lack of correlation between TBARS production and PUFA degradation during incubation of membrane erythrocytes in an OH⋅ (Fe2+/H2O2) generator system

We investigated the effects of an OH^⋅ (Fe²⁺/H₂O₂) generator system of erythrocyte membrane, particularly the time-course of lipid peroxidation as estimated by measurement of conjugated dienes, thiobarbituric reactive substances (TBARS), lipofuscin-like pigments, and α-tocopherol. Polyunsaturated fatty acids (PUFAs), especially arachidonic acid (20∶4 ω 6) and docosahexenoic acid (22∶6 ω 3), were also measured. Erythrocyte membranes were suspended in phosphate buffer containing Fe²⁺ (200 μM) and H₂O₂ (1.42 mM), and incubated in a shaking water bath at 37°C. Initially, there was an increase in TBARS and lipofuscin-like pigments, two well-known end products of PUFA oxidative degradation, whereas PUFAs remained unchanged (incubation time: 1 h). After two or more hours of incubation, marked lipid peroxidation was noted, with the appearance of conjugated dienes and a decrease of PUFAs, indicating that lipid peroxidation had occurred after a lag phase during which TBARS were not produced from PUFAs. This suggests that another OH^⋅ target was involved.     

Evolution of the WANCY region in amniote mitochondrial DNA

In most vertebrate mitochondrial genomes, the site for initiation of light-strand replication, OL, is found within a cluster of five transfer RNA (tRNA) genes (tRNA(Trp), tRNA(Ala), tRNA(Asn), tRNA(Cys), and tRNA(Tyr)). This region and part of the adjacent cytochrome c oxydase subunit I (COI) gene were sequenced for two crocodilian, two turtle, and one snake species and for Sphenodon punctatus; part of the adjacent nicotinamide adenine dinucleotide dehydrogenase subunit 2 (ND2) gene was also sequenced for the crocodilian and turtle species. All had the typical vertebrate gene order. The turtles and the snake have a lengthy noncoding sequence between the tRNA(Asn) and tRNA(Cys) genes that we assumed to be homologous to the mammalian OL. The crocodilians and Sphenodon lack such a sequence, a condition they share with birds. Most proposed phylogenies for the amniotes require that OL at this position was lost at least twice during their diversification or was evolved independently more than once. Within the five tRNA genes, frequencies of substitutions are much higher in loops than in stems. Many loops vary dramatically in size among the species; in the most extreme case, the D-arm of the Sphenodon tRNA(Cys) is a "D-arm replacement" loop of seven nucleotides. Frequency of transitions in stems is relatively uniform across tRNAs, but frequency of transversions varies greatly. Mismatches in stems are infrequent, and their relative frequency in a specific tRNA is unrelated to the frequency of substitution in the corresponding gene. Several features of mammalian mitochondrial tRNAs are conserved in WANCY tRNAs throughout amniotes. The inferred initiation codon for COI is GTG in crocodilians, turtles, and the snake, a condition they share with fishes, certain amphibians, and birds. TTG appears to be the initiation codon for COI in Sphenodon; if correct, this would be a novel initiation codon for vertebrate mitochondrial DNA. Phylogenetic analyses of the inferred amino acid sequences of ND2 and COI support the sister-group relationship of birds and crocodilians and suggest that mammals are an early derived lineage within the amniotes.      

Inflammatory and Immunological parameters in adults with Down syndrome

Background  

The increase in life expectancy within the general population has resulted in an increasing number of elderly adults, including patients with Down syndrome (DS), with a current life expectancy of about 50 years. We evaluate the parameters of humoral and cellular immune response, the quantitative expression of the regulator of calcineurin1 gene (RCAN1) and the production of cytokines. The study group consisted of adults DS (n = 24) and a control group with intellectual disability without Down syndrome (ID) (n = 21) and living in a similar environmental background. It was evaluated serology, immunophenotyping, the quantitative gene expression of RCAN1 and the production of cytokines.     

Sulfatide and GM1 ganglioside modulate the high-affinity dopamine uptake in rat striatal synaptosomes: evidence for the involvement of their ionic charges

The present study was undertaken to examine the effects of the anionic glycolipids GM1 ganglioside and sulfatide on the high-affinity dopamine (DA) uptake in rat striatal synaptosomes.After 1h of incubation, GM1 stably bound to synaptosomes and modified the activity of the neuronal dopamine transporter (DAT). With 1.2 and 12 microM GM1, V(max) decreased by 13 and 23%, respectively, reflecting a slight reduction of the number of functional uptake sites and K(m) was lowered by 21 and 33%, thus showing an increase of the affinity. Treatment of synaptosomes with 1.2 microM of sulfatide, which possesses an anionic sulfated group, led to a similar decrease of V(max) (19%) than GM1, but to a significantly higher reduction of K(m) (35%). In fact, sulfatide associated to synaptosomes in a 3.5-fold higher extent than GM1. Conversely, when GM1 and sulfatide were replaced by GM1 alcohol and galactosylceramide, respectively, no modification of the DA uptake occurred, although these neutral glycolipids incorporated into the synaptosomes to the same extent as the related anionic compounds.Altogether, these results demonstrate the key role of negative charges linked to the oligosaccharide chains of glycolipids in the modulation of DA transport across the synaptosomal membrane.     

The oxindole/imidazole derivative C16 reduces in vivo brain PKR activation

Inhibition of double-stranded RNA-dependent protein kinase (PKR) represents an interesting strategy for neuroprotection. However, inhibiting this kinase which triggers the apoptotic process could favour in counterpart cell proliferation and tumorigenesis. Here, we use an in vivo model of 7-day-old rat displaying a high activation of brain PKR to investigate the effects of a new PKR inhibitor identified as an oxindole/imidazole derivative (C16). We show for the first time that acute systemic injection of C16 specifically inhibits the apoptotic PKR/eIF2alpha signaling pathway without stimulating the proliferative mTOR/p70S6K signaling mechanism.     

Satellog: A database for the identification and prioritization of satellite repeats in disease association studies

Background  

To date, 35 human diseases, some of which also exhibit anticipation, have been associated with unstable repeats. Anticipation has been reported in a number of diseases in which repeat expansion may have a role in etiology. Despite the growing importance of unstable repeats in disease, currently no resource exists for the prioritization of repeats. Here we present Satellog, a database that catalogs all pure 1–16 repeat unit satellite repeats in the human genome along with supplementary data. Satellog analyzes each pure repeat in UniGene clusters for evidence of repeat polymorphism.