Homology among Escherichia coli K1 and K92 polysialytransferases.

The neuS-encoded polysialytransferase (polyST) in Escherichia coli K1 catalyzes synthesis of polysialic acid homopolymers composed of unbranched sialyl alpha 2,8 linkages. Subcloning and complementation experiments showed that the K1 neuS was functionally interchangeable with the neuS from E. coli K92 (S. M. Steenbergen, T. J. Wrona, and E. R. Vimr, J. Bacteriol. 174:1099-1108, 1992), which synthesizes polysialic acid capsules with alternating sialyl alpha 2,8-2,9 linkages. To better understand the relationship between these polySTs, the complete K92 neuS sequence was determined. The results demonstrated that K1 and K92 neuS genes are homologous and indicated that the K92 copy may have evolved from its K1 homolog. Both K1 and K92 structural genes comprised 1,227 bp. There were 156 (12.7%) differences between the two sequences; among these mutations, 55 did not affect the derived primary structure of K92 polyST and hence were synonymous with the K1 sequence. Assuming maximum parsimony, another estimated 17 synonymous mutations plus 84 nonsynonymous mutations could account for the 70 amino acid replacements in K92 polyST; 36 of these replacements were judged to be conservative when compared with those of K1 polyST. There were no changes detected in the first 146 5' or last 129 3' bp of either gene, suggesting, in addition to the observed mutational differences, the possibility of a past recombination event between neuS loci of two different kps clusters. The results indicate that relatively few amino acid changes can account for the evolution of a glycosyltransferase with novel linkage specificity.     

Effects of Oenothera biennis L. and Hypericum perforatum L. extracts on some central nervous system myelin proteins,brain histopathology and oxidative stress in mice with experimental autoimmune encephalomyelitis

We investigated the effects of Oenothera biennis L. and Hypericum perforatum L. extracts on brain tissue histopathology, myelin oligodendrocyte glycoprotein (MOG), myelin basic protein (MBP), total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) in mice with experimental autoimmune encephalomyelitis (EAE). Forty-seven C57BL/6J mice were divided into the following groups: multiple sclerosis (MS), control (healthy mice), MS + H. perforatum treated (MS + HP), MS + O. biennis treated (MS + OB). All groups except the control group were immunized by EAE methods. Two weeks after the immunization, the mice in the MS + HP group were fed normal food containing 18 ? 21 g/kg H. perforatum extract, the mice in MS + OB group were fed normal food containing 18 ? 21 g/kg O. biennis extract, and the mice in control and MS groups were fed normal food for six weeks. Brain tissue samples were collected from all mice for histopathological and biochemical analysis. Clinical signs of the disease were scored using functional systems scores (FSS) daily. The H. perforatum and O. biennis extracts ameliorated the increased brain tissue MOG and MBP values for animals with MS. H. perforatum and O. biennis extract decreased the TOS and OSI values for brain tissue and increased TAS levels in brain tissue of animals with MS. In addition, H. perforatum and O. biennis extracts decreased the clinical signs at the end of the experiment compared to the beginning of extract administration. We found that myelin was lost in MS group vs. control group. H. perforatum and O. biennis extract treatments decreased the amount of myelin loss in the MS + HP and MS + OB groups. We also observed amyloid deposition on vascular walls, in the cytoplasm of the neurons and in the intercellular space in the MS group. O. biennis and H. perforatum treated groups exhibited neither abnormal amyloid deposition nor obvious cell infiltration. The beneficial effects of O. biennis and H. perforatum for attenuating myelin loss and amyloid deposition suggest their therapeutic utility for treatment of MS.     

Ginger and alpha lipoic acid ameliorate age-related ultrastructural changes in rat liver

Because of the important role that oxidative stress is thought to play in the aging process, antioxidants could be candidates for preventing its related pathologies. We investigated the ameliorative effects of two antioxidant supplements, ginger and alpha lipoic acid (ALA), on hepatic ultrastructural alterations in old rats. Livers of young (4 months) and old (24 months) Wistar rats were studied using transmission electron microscopy. Livers of old rats showed sinusoidal collapse and congestion, endothelial thickening and defenestration, and inconsistent perisinusoidal extracellular matrix deposition. Aged hepatocytes were characterized by hypertrophy, cytoplasmic vacuolization and a significant increase in the volume densities of the nuclei, mitochondria and dense bodies. Lipofuscin accumulation and decreased microvilli in bile canaliculi and space of Disse also were observed. The adverse alterations were ameliorated significantly by both ginger and ALA supplementation; ALA was more effective than ginger. Ginger and ALA appear to be promising anti-aging agents based on their amelioration of ultrastructural alterations in livers of old rats.     

Alterations in apoptotic signaling in human idiopathic cardiomyopathic hearts in failure

Dilated cardiomyopathy, a disease of unknown etiology and pathogenesis, is associated with heart failure and compensatory hypertrophy. Although cell and animal models suggest a role for altered gene expression in the transition to heart failure, there is a paucity of data derived from the study of human heart tissue. In this study, we used DNA microarray profiling to investigate changes in the expression of genes involved in apoptosis that occur in human idiopathic dilated cardiomyopathic hearts that had progressed to heart failure. We observed altered gene expression consistent with a proapoptotic shift in the TNF-alpha signaling pathway. Specifically, we found decreased expression of TNF-alpha- and NF-kappaB-induced antiapoptotic genes such as growth arrest and DNA damage-inducible (GADD)45beta, Flice inhibitory protein (FLIP), and TNF-induced protein 3 (A20). Consistent with a role for apoptosis in heart failure, we also observed a significant decrease in phosphorylation of BAD at Ser-112. This study identifies several pathways that are altered in human heart failure and provides new targets for therapy.     

Unravelling developmental disregard in children with unilateral cerebral palsy by measuring event-related potentials during a simple and complex task

Background

In a subset of children with unilateral Cerebral Palsy (CP) a discrepancy between capacity and performance of the affected upper limb can be observed. This discrepancy is known as Developmental Disregard (DD). Though the phenomenon of DD has been well documented, its underlying cause is still under debate. DD has originally been explained based on principles of operant conditioning. Alternatively, it has been proposed that DD results from a diminished automaticity of movements, resulting in an increased cognitive load when using the affected hand. To investigate the amount of involved cognitive load we studied Event-Related Potentials (ERPs) preceding task-related motor responses during a single-hand capacity and a dual-hand performance task. It was hypothesised that children with DD show alterations related to long-latency ERP components when selecting a response with the affected upper limb, reflecting increased cognitive load in order to generate an adequate response and especially so within the dual-hand task.

Methods

Fifteen children with unilateral CP participated in the study. One of the participants was excluded due to major visual impairments. Seven of the remaining participants displayed DD. The other seven children served as a control group. All participants performed two versions of a cue-target paradigm, a single-hand capacity and a dual-hand performance task. The ERP components linked to target presentation were inspected: the mid-latency P2 component and the consecutive long-latency N2b component.

Results

In the dual-hand performance task children with DD showed an enhancement in mean amplitude of the long-latency N2b component when selecting a response with their affected hand. No differences were found regarding the amplitude of the mid-latency P2 component. No differences were observed regarding the single-hand capacity task. The control group did not display any differences in ERPs linked to target evaluation processes between both hands.

Conclusion

These electrophysiological findings show that DD is associated with increased cognitive load when movements are prepared with the affected hand during a dual-hand performance task. These findings confirm behavioural observations, advance our insights on the neural substrate of DD and have implications for therapy.     

Algorithmic approaches to aid species' delimitation in multidimensional morphospace

Background  

The species is a fundamental unit of biological pattern and process, but its delimitation has proven a ready source of argument and disagreement. Here, we discuss four key steps that utilize statistical thresholds to describe the morphological variability within a sample and hence assess whether there is evidence for one or multiple species. Once the initial set of biologically relevant traits on comparable individuals has been identified, there is no need for the investigator to hypothesise how specimens might be divided among groups, nor the traits on which groups might be separated.     

Ciliopathies with skeletal anomalies and renal insufficiency due to mutations in the IFT-A gene WDR19

A subset of ciliopathies, including Sensenbrenner, Jeune, and short-rib polydactyly syndromes are characterized by skeletal anomalies accompanied by multiorgan defects such as chronic renal failure and retinitis pigmentosa. Through exome sequencing we identified compound heterozygous mutations in WDR19 in a Norwegian family with Sensenbrenner syndrome. In a Dutch family with the clinically overlapping Jeune syndrome, a homozygous missense mutation in the same gene was found. Both families displayed a nephronophthisis-like nephropathy. Independently, we also identified compound heterozygous WDR19 mutations by exome sequencing in a Moroccan family with isolated nephronophthisis. WDR19 encodes IFT144, a member of the intraflagellar transport (IFT) complex A that drives retrograde ciliary transport. We show that IFT144 is absent from the cilia of fibroblasts from one of the Sensenbrenner patients and that ciliary abundance and morphology is perturbed, demonstrating the ciliary pathogenesis. Our results suggest that isolated nephronophthisis, Jeune, and Sensenbrenner syndromes are clinically overlapping disorders that can result from a similar molecular cause.