Delineating Electrogenic Reactions during Lactose/H+ Symport†

Electrogenic reactions accompanying downhill lactose/H+ symport catalyzed by the lactose permease of Escherichia coli (LacY) have been assessed using solid-supported membrane-based electrophysiology with improved time resolution. Rates of charge translocation generated by purified LacY reconstituted into proteoliposomes were analyzed over a pH range from 5.2 to 8.5, which allows characterization of two electrogenic steps in the transport mechanism: (i) a weak electrogenic reaction triggered by sugar binding and observed under conditions where H+ translocation is abolished either by acidic pH or by a Glu325 -> Ala mutation in the H+ binding site (this step with a rate constant of ~200 s-1 for wildtype LacY leads to an intermediate proposed to represent an “occluded” state) and (ii) a major electrogenic reaction corresponding to 94% of the total charge translocated at pH 8, which is pH-dependent with a maximum rate of ~30 s-1 and a pK of 7.5. This partial reaction is assigned to rate-limiting H+ release on the cytoplasmic side of LacY during turnover. These findings together with previous electrophysiological results and biochemical-biophysical studies are included in an overall kinetic mechanism that allows delineation of the electrogenic steps in the reaction pathway

Muscle activation during gait in children with Duchenne muscular dystrophy

The aim of this prospective study was to investigate changes in muscle activity during gait in children with Duchenne muscular Dystrophy (DMD). Dynamic surface electromyography recordings (EMGs) of 16 children with DMD and pathological gait were compared with those of 15 control children. The activity of the rectus femoris (RF), vastus lateralis (VL), medial hamstrings (HS), tibialis anterior (TA) and gastrocnemius soleus (GAS) muscles was recorded and analysed quantitatively and qualitatively. The overall muscle activity in the children with DMD was significantly different from that of the control group. Percentage activation amplitudes of RF, HS and TA were greater throughout the gait cycle in the children with DMD and the timing of GAS activity differed from the control children. Significantly greater muscle coactivation was found in the children with DMD. There were no significant differences between sides. Since the motor command is normal in DMD, the hyper-activity and co-contractions likely compensate for gait instability and muscle weakness, however may have negative consequences on the muscles and may increase the energy cost of gait. Simple rehabilitative strategies such as targeted physical therapies may improve stability and thus the pattern of muscle activity

Pathway-Based Evaluation in Early Onset Colorectal Cancer Suggests Focal Adhesion and Immunosuppression along with Epithelial-Mesenchymal Transition

Colorectal cancer (CRC) has one of the highest incidences among all cancers. The majority of CRCs are sporadic cancers that occur in individuals without family histories of CRC or inherited mutations. Unfortunately, whole-genome expression studies of sporadic CRCs are limited. A recent study used microarray techniques to identify a predictor gene set indicative of susceptibility to early-onset CRC. However, the molecular mechanisms of the predictor gene set were not fully investigated in the previous study. To understand the functional roles of the predictor gene set, in the present study we applied a subpathway-based statistical model to the microarray data from the previous study and identified mechanisms that are reasonably associated with the predictor gene set. Interestingly, significant subpathways belonging to 2 KEGG pathways (focal adhesion; natural killer cell-mediated cytotoxicity) were found to be involved in the early-onset CRC patients. We also showed that the 2 pathways were functionally involved in the predictor gene set using a text-mining technique. Entry of a single member of the predictor gene set triggered a focal adhesion pathway, which confers anti-apoptosis in the early-onset CRC patients. Furthermore, intensive inspection of the predictor gene set in terms of the 2 pathways suggested that some entries of the predictor gene set were implicated in immunosuppression along with epithelial-mesenchymal transition (EMT) in the early-onset CRC patients. In addition, we compared our subpathway-based statistical model with a gene set-based statistical model, MIT Gene Set Enrichment Analysis (GSEA). Our method showed better performance than GSEA in the sense that our method was more consistent with a well-known cancer-related pathway set. Thus, the biological suggestion generated by our subpathway-based approach seems quite reasonable and warrants a further experimental study on early-onset CRC in terms of dedifferentiation or differentiation, which is underscored in EMT and immunosuppression

Heat and water stress induce unique transcriptional signatures of heat-shock proteins and transcription factors in grapevine

Grapevine is an extremely important crop worldwide. In southern Europe, post-flowering phases of the growth cycle can occur under high temperatures, excessive light, and drought conditions at soil and/or atmospheric level. In this study, we subjected greenhouse grown grapevine, variety Aragonez, to two individual abiotic stresses, water deficit stress (WDS), and heat stress (HS). The adaptation of plants to stress is a complex response triggered by cascades of molecular networks involved in stress perception, signal transduction, and the expression of specific stress-related genes and metabolites. Approaches such as array-based transcript profiling allow assessing the expression of thousands of genes in control and stress tissues. Using microarrays, we analyzed the leaf transcriptomic profile of the grapevine plants. Photosynthesis measurements verified that the plants were significantly affected by the stresses applied. Leaf gene expression was obtained using a high-throughput transcriptomic grapevine array, the 23K custom-made Affymetrix Vitis GeneChip. We identified 1,594 genes as differentially expressed between control and treatments and grouped them into ten major functional categories using MapMan software. The transcriptome of Aragonez was more significantly affected by HS when compared with WDS. The number of genes coding for heat-shock proteins and transcription factors expressed solely in response to HS suggesting their expression as unique signatures of HS. However, a cross-talk between the response pathways to both stresses was observed at the level of AP2/ERF transcription factors

Postulated Vasoactive Neuropeptide Autoimmunity in Fatigue-Related Conditions: A Brief Review and Hypothesis

Disorders such as chronic fatigue syndrome (CFS) and gulf war syndrome (GWS) are characterised by prolonged fatigue and a range of debilitating symptoms of pain, intellectual and emotional impairment, chemical sensitivities and immunological dysfunction. Sudden infant death syndrome (SIDS) surprisingly may have certain features in common with these conditions. Post-infection sequelae may be possible contributing factors although ongoing infection is unproven. Immunological aberration may prove to be associated with certain vasoactive neuropeptides (VN) in the context of molecular mimicry, inappropriate immunological memory and autoimmunity

Protective Intestinal Effects of Pituitary Adenylate Cyclase Activating Polypeptide

Pituitary adenylate cyclase activating polypeptide (PACAP) is an endogenous neuropeptide widely distributed throughout the body, including the gastrointestinal tract. Several effects have been described in human and animal intestines. Among others, PACAP infl uences secretion of intestinal glands, blood fl ow, and smooth muscle contraction. PACAP is a well-known cytoprotective peptide with strong anti-apoptotic, anti-infl ammatory, and antioxidant effects. The present review gives an overview of the intestinal protective actions of this neuropeptide. Exogenous PACAP treatment was protective in a rat model of small bowel autotransplantation. Radioimmunoassay (RIA) analysis of the intestinal tissue showed that endogenous PACAP levels gradually decreased with longer-lasting ischemic periods, prevented by PACAP addition. PACAP counteracted deleterious effects of ischemia on oxidative stress markers and cytokines. Another series of experiments investigated the role of endogenous PACAP in intestines in PACAP knockout (KO) mice. Warm ischemia–reperfusion injury and cold preservation models showed that the lack of PACAP caused a higher vulnerability against ischemic periods. Changes were more severe in PACAP KO mice at all examined time points. This fi nding was supported by increased levels of oxidative stress markers and decreased expression of antioxidant molecules. PACAP was proven to be protective not only in ischemic but also in infl ammatory bowel diseases. A recent study showed that PACAP treatment prolonged survival of Toxoplasma gondii infected mice suffering from acute ileitis and was able to reduce the ileal expression of proinfl ammatory cytokines. We completed the present review with recent clinical results obtained in patients suffering from infl ammatory bowel diseases. It was found that PACAP levels were altered depending on the activity, type of the disease, and antibiotic therapy, suggesting its probable role in infl ammatory events of the intestine

The effects of instrumental action on perceptual hand maps

Perceiving the external spatial location of body parts using position sense requires that immediate proprioceptive afferent signals be integrated with information about body size and shape. Longo and Haggard (Proc Natl Acad Sci USA 107:11727–11732, 2010) developed a method to measure perceptual hand maps reflecting this metric information about body size and shape. In this paradigm, participants indicate the perceived location of landmarks on their occluded hand by pointing with a long baton held in their other hand. By comparing the relative location of judgments of different hand landmarks, perceptual hand maps can be constructed and compared to actual hand structure. The maps show large and highly stereotyped distortions. Here, I investigated the potential effect of biases related to active motor control of the hand doing the pointing in these distortions. Participants localized the fingertip and knuckle of each finger on their occluded left hand either by actively pointing with a baton held in their right hand (pointing condition) or by giving verbal commands to an experimenter on how to move the baton (verbal condition). Similar distortions were clearly apparent in both conditions, suggesting that they are not an artifact of motor control biases related to the pointing hand

Artritele reactive și infecţiile urogenitale

Summary The objective of this investigation was to estimate the role of the urogenital infection for Reactive Arthritis (ReA), clinical features, the aspects of treatment, evolution and prognostic. Was demonstrated the prevalence of men for ReA. The most common cause were chlamydial, mycoplasmal and mixt infection. Early recognition and elimination of the triggering microbe seems important for the arthritis outcome in ReA