Communicative interactions improve visual detection of biological motion

Background

In the context of interacting activities requiring close-body contact such as fighting or dancing, the actions of one agent can be used to predict the actions of the second agent [1]. In the present study, we investigated whether interpersonal predictive coding extends to interactive activities – such as communicative interactions - in which no physical contingency is implied between the movements of the interacting individuals.

Methodology/Principal Findings

Participants observed point-light displays of two agents (A and B) performing separate actions. In the communicative condition, the action performed by agent B responded to a communicative gesture performed by agent A. In the individual condition, agent A''s communicative action was substituted with a non-communicative action. Using a simultaneous masking detection task, we demonstrate that observing the communicative gesture performed by agent A enhanced visual discrimination of agent B.

Conclusions/Significance

Our finding complements and extends previous evidence for interpersonal predictive coding, suggesting that the communicative gestures of one agent can serve as a predictor for the expected actions of the respondent, even if no physical contact between agents is implied.     

A Study of Glutathione <Emphasis Type="Italic">S</Emphasis>-transferase pi Expression in Central Nervous System of Subjects with Amyotrophic Lateral Sclerosis Using RNA Extraction from Formalin-Fixed,Paraffin-Embedded Material

The expression of glutathione S-transferase pi (GST pi), an enzyme responsible for inactivation of a large variety of toxic compounds was studied in spinal cord, motor and sensory brain cortex obtained from patients who died in the course of amyotrophic lateral sclerosis (ALS). The studies were performed on formalin-fixed, paraffin-embedded (FFPE) and freshly frozen tissues. The method of RNA isolation from FFPE was modified. A significant decrease of GST pi-mRNA expression was found in cervical spinal cord and motor brain cortex of ALS subjects comparing to analogue control tissues (P < 0.01), as well as in motor cortex of ALS subjects comparing to their sensory cortex (P < 0.05). In spinal cords the decrease in GST pi-mRNA expression was accompanied by a decrease of GST pi protein level. Results indicated lowered GST pi expression on both mRNA and protein levels in the regions of nervous system affected by ALS. The non-properly inactivated by GST toxic electrophiles and organic peroxides may thus contribute to motor neurons damage.     

P2 nucleotide receptors on C2C12 satellite cells

In developing muscle cells environmental stimuli transmitted by purines binding to the specific receptors are crucial proliferation regulators. C2C12 myoblasts express numerous purinergic receptors representing both main classes: P2X and P2Y. Among P2Y receptors we have found the expression of P2Y(1), P2Y(2), P2Y(4), P2Y(6) and P2Y(12) family members while among P2X receptors P2X(4), P2X(5) and P2X(7) were discovered. We have been able to show that activation of those receptors is responsible for ERK class kinase activity, responsible for regulation of cell proliferation pathway. We have also demonstrated that this activity is calcium dependent suggesting Ca(2+) ions as secondary messenger between receptor and kinase regulatory system. More specifically, we do suspect that in C2C12 myoblasts calcium channels of P2X receptors, particularly P2X(5) play the main role in proliferation regulation. In further development of myoblasts into myotubes, when proliferation is gradually inhibited, the pattern of P2 receptors is changed. This phenomenon is followed by diminishing of the P2Y(2)-dependent Ca(2+) signaling, while the mRNA expression of P2Y(2) receptor reminds still on the high level. Moreover, P2X(2) receptor mRNA, absent in myoblasts appears in myotubes. These data show that differentiation of C2C12 cell line satellite myoblasts is accompanied by changes in P2 receptors expression pattern.     

Gene conversion and crossing over along the 405-kb left arm of Saccharomyces cerevisiae chromosome VII

Gene conversions and crossing over were analyzed along 10 intervals in a 405-kb region comprising nearly all of the left arm of chromosome VII in Saccharomyces cerevisiae. Crossover interference was detected in all intervals as measured by a reduced number of nonparental ditypes. We have evaluated interference between crossovers in adjacent intervals by methods that retain the information contained in tetrads as opposed to single segregants. Interference was seen between intervals when the distance in the region adjacent to a crossover was < approximately 35 cM (90 kb). At the met13 locus, which exhibits approximately 9% gene conversions, those gene conversions accompanied by crossing over exerted interference in exchanges in an adjacent interval, whereas met13 gene conversions without an accompanying exchange did not show interference. The pattern of exchanges along this chromosome arm can be represented by a counting model in which there are three nonexchange events between adjacent exchanges; however, maximum-likelihood analysis suggests that approximately 8-12% of the crossovers on chromosome VII arise by a separate, noninterfering mechanism.     

Glutathione S-transferase pi as a target for tricyclic antidepressants in human brain

GST pi, the main glutathione S-transferase isoform present in the human brain, was isolated from various regions of the brain and the in vitro effect of tricyclic antidepressants on its activity was studied. The results indicated that amitripyline and doxepin - derivatives of dibenzcycloheptadiene, as well as imipramine and clomipramine - derivatives of dibenzazepine, inhibit the activity of GST pi from frontal and parietal cortex, hippocampus and brain stem. All these tricyclics are noncompetitive inhibitors of the enzyme with respect to reduced glutathione and noncompetitive (amitripyline, doxepin) or uncompetitive (imipramine, clomipramine) with respect to the electrophilic substrate. Their inhibitory effect is reversible and it depends on the chemical structure of the tricyclic antidepressants rather than on the brain localization of the enzyme. We conclude that the interaction between GST pi and the drugs may reduce their availability in the brain and thus affect their therapeutic activity. On the other hand, tricyclic antidepressants may decrease the efficiency of the enzymatic barrier formed by GST and increase the exposure of brain to toxic electrophiles. Reactive electrophiles not inactivated by GST may contribute in adverse effects caused by these drugs.     

Phylogeography of Y-chromosome haplogroup I reveals distinct domains of prehistoric gene flow in europe

To investigate which aspects of contemporary human Y-chromosome variation in Europe are characteristic of primary colonization, late-glacial expansions from refuge areas, Neolithic dispersals, or more recent events of gene flow, we have analyzed, in detail, haplogroup I (Hg I), the only major clade of the Y phylogeny that is widespread over Europe but virtually absent elsewhere. The analysis of 1,104 Hg I Y chromosomes, which were identified in the survey of 7,574 males from 60 population samples, revealed several subclades with distinct geographic distributions. Subclade I1a accounts for most of Hg I in Scandinavia, with a rapidly decreasing frequency toward both the East European Plain and the Atlantic fringe, but microsatellite diversity reveals that France could be the source region of the early spread of both I1a and the less common I1c. Also, I1b*, which extends from the eastern Adriatic to eastern Europe and declines noticeably toward the southern Balkans and abruptly toward the periphery of northern Italy, probably diffused after the Last Glacial Maximum from a homeland in eastern Europe or the Balkans. In contrast, I1b2 most likely arose in southern France/Iberia. Similarly to the other subclades, it underwent a postglacial expansion and marked the human colonization of Sardinia ~9,000 years ago.     

Effect of Rho-associated kinase inhibition on actin cytoskeleton structure and calcium response in glioma C6 cells

The role of actin cytoskeleton functional state in glioma C6 cell morphology and calcium signaling was investigated through modification of myosin II activity by blocking Rho-associated kinase with the specific inhibitor Y-27632. Treatment of glioma C6 cells with ROCK inhibitor resulted in actin cytoskeleton reorganization and also in the changed shape and distribution of mitochondria. Changes in the distribution of ER, the main calcium store in glioma C6 cells, were not visible. The inhibition of myosin II activity influences the first phase of calcium signaling evoked by agonist, and both phases of thapsigargin-evoked calcium response. We suggest that the observed increase in Ca2+ release from intracellular stores induced by IP3 formation as well as inhibition of SERCA ATPase is at least in part related to severely affected mitochondria. Enhancement of capacitative calcium entry evoked by thapsigargin is probably associated with the reorganization of the acto-myosin II system. ATP-induced calcium response presents no changes in the second phase. We observed that ATP stimulation of Y-27632 pretreated cells leads to immediate morphological rearrangement of glioma C6 cells. It is a consequence of actin cytoskeleton reorganization: formation of stress fibers and relocation of phosphorylated myosin II to actin filaments. It seems that the agonist-evoked strong calcium signal may be sufficient for myosin II activation and the stress fiber organization. This is the first work showing the dependence between the functional state of the acto-myosin II system and calcium signaling stressing the reversible character of this relationship.     

Arginase as a useful factor for the diagnosis of colorectal cancer liver metastases

The present work is a continuation of studies on arginase as a marker in the diagnosis of colorectal cancer liver metastases (CRCLM). The purpose of the study was the evaluation of the arginase test in comparison with other colorectal cancer tests such as CEA, CA 19-9 and biochemical markers of liver function such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The studies were conducted on blood serum from 85 patients with CRCLM obtained one to two days before tumor resection. The control group comprised 140 healthy blood donors and 81 patients with various non-malignant gastrointestinal diseases. Raised arginase activity was observed in serum of 85% of CRCLM patients, whereas elevated levels of CEA and CA 19-9 were found in 63% and 42% of patients, respectively. The combination of CEA or CA 19-9 with the arginase assay improved their sensitivity, but the sensitivity of the combined parameters was not higher than that of the arginase test itself. AST and ALT activities were increased in about 30% of CRCLM patients. The specificity of the arginase test calculated for 221 control subjects was 76%. It can thus be concluded that the determination of serum arginase activity can be helpful in the diagnosis of patients with colorectal cancer liver metastases.     

Different regulation of phospholipase D activity in glioma C6 cells by sphingosine, propranolol, imipramine and phorbol ester

In has been found that sphingosine, propranolol, imipramine and phorbol ester (12-O-tetradecanoylphorbol-13-acetate, TPA) have a stimulatory effect on phospholipase D activity in glioma C6 cells. The cells were prelabelled with [1-(14)C]palmitic acid and phospholipase D-mediated synthesis of [(14)C]phosphatidylethanol was measured. The enhancing effect of TPA was almost completely blocked by a specific protein kinase C inhibitor, GF 109203X. In contrast, GF 109203X failed to inhibit the sphingosine, imipramine and propranolol stimulatory effects, indicating that their stimulation was independent of protein kinase C. The effect of TPA on phospholipase D was also blocked by imipramine and propranolol, whereas sphingosine additively potentiated TPA-mediated phospholipase D activity, both at shorter and longer (2-60 min) times of incubation. These results suggest that in glioma C6 cells, sphingosine is not only involved in a different phospholipase D activation than the TPA regulatory system, but also that it operates in a different compartment of the cell.     

Large inverted repeats in the vicinity of a single double-strand break strongly affect repair in yeast diploids lacking Rad51

DNA double-strand breaks (DSBs) are critical lesions that can lead to cell death or chromosomal rearrangements. Rad51 is necessary for most mitotic and meiotic DSB repair events, although a number of RAD51-independent pathways exist. Previously, we described DSB repair in rad51Delta yeast diploids that was stimulated by a DNA region termed "facilitator of break-induced replication" (FBI) located approximately 30kb from the site of an HO-induced DSB. Here, we demonstrate that FBI is a large inverted DNA repeat that channels the repair of DSBs into the single-strand annealing-gross chromosomal rearrangements (SSA-GCR) pathway. Further, analysis of DSB repair in rad54Delta cells allowed us to propose that the SSA-GCR repair pathway is suppressed in the presence of Rad51p. Therefore, an additional role of Rad51 might be to protect eukaryotic genomes from instabilities by preventing chromosomal rearrangements.