Mechanisms and development of self–other distinction in dyads and groups

This opinion piece offers a commentary on the four papers that address the theme of the development of self and other understanding with a view to highlighting the important contribution of developmental research to understanding of mechanisms of social cognition. We discuss potential mechanisms linking self–other distinction and empathy, implications for grouping motor, affective and cognitive domains under a single mechanism, applications of these accounts for joint action and finally consider self–other distinction in group versus dyadic settings.     

Body Size,Growth and Life Span: Implications for the Polewards Range Shift of Octopus tetricus in South-Eastern Australia

Understanding the response of any species to climate change can be challenging. However, in short-lived species the faster turnover of generations may facilitate the examination of responses associated with longer-term environmental change. Octopus tetricus, a commercially important species, has undergone a recent polewards range shift in the coastal waters of south-eastern Australia, thought to be associated with the southerly extension of the warm East Australian Current. At the cooler temperatures of a polewards distribution limit, growth of a species could be slower, potentially leading to a bigger body size and resulting in a slower population turnover, affecting population viability at the extreme of the distribution. Growth rates, body size, and life span of O. tetricus were examined at the leading edge of a polewards range shift in Tasmanian waters (40°S and 147°E) throughout 2011. Octopus tetricus had a relatively small body size and short lifespan of approximately 11 months that, despite cooler temperatures, would allow a high rate of population turnover and may facilitate the population increase necessary for successful establishment in the new extended area of the range. Temperature, food availability and gender appear to influence growth rate. Individuals that hatched during cooler and more productive conditions, but grew during warming conditions, exhibited faster growth rates and reached smaller body sizes than individuals that hatched into warmer waters but grew during cooling conditions. This study suggests that fast growth, small body size and associated rapid population turnover may facilitate the range shift of O. tetricus into Tasmanian waters.     

Glycans from Fasciola hepatica Modulate the Host Immune Response and TLR-Induced Maturation of Dendritic Cells

Helminths express various carbohydrate-containing glycoconjugates on their surface, and they release glycan-rich excretion/secretion products that can be very important in their life cycles, infection and pathology. Recent evidence suggests that parasite glycoconjugates could play a role in the evasion of the immune response, leading to a modified Th2-polarized immune response that favors parasite survival in the host. Nevertheless, there is limited information about the nature or function of glycans produced by the trematode Fasciola hepatica, the causative agent of fasciolosis. In this paper, we investigate whether glycosylated molecules from F. hepatica participate in the modulation of host immunity. We also focus on dendritic cells, since they are an important target of immune-modulation by helminths, affecting their activity or function. Our results indicate that glycans from F. hepatica promote the production of IL-4 and IL-10, suppressing IFNγ production. During infection, this parasite is able to induce a semi-mature phenotype of DCs expressing low levels of MHCII and secrete IL-10. Furthermore, we show that parasite glycoconjugates mediate the modulation of LPS-induced maturation of DCs since their oxidation restores the capacity of LPS-treated DCs to secrete high levels of the pro-inflammatory cytokines IL-6 and IL-12/23p40 and low levels of the anti-inflammatory cytokine IL-10. Inhibition assays using carbohydrates suggest that the immune-modulation is mediated, at least in part, by the recognition of a mannose specific-CLR that signals by recruiting the phosphatase Php2. The results presented here contribute to the understanding of the role of parasite glycosylated molecules in the modulation of the host immunity and might be useful in the design of vaccines against fasciolosis.     

Transient expression of simple epithelial keratins by mesenchymal cells of regenerating newt limb

Structural proteins of the intermediate filament family are an early indicator of differentiation before organogenesis becomes apparent. Keratin intermediate filaments are characteristically expressed only by epithelial and not by mesenchymal cells. Here we show, using monoclonal antibodies, a transient expression of the keratin pair 8 and 18 in a population of mesenchymal cells in the regenerating newt limb, specifically in the undifferentiated progenitor cells (blastemal cells) which give rise to the new tissues. These keratins are also expressed in cultured limb cells that can differentiate into muscle. In contrast no reactivity with anti-keratin 8 and 18 antibodies was observed in the newt limb bud at an early stage of development, indicating a molecular difference between the developing and regenerating limb. The molecular weights of the newt proteins detected by these antibodies are very similar to those of human keratins 8 and 18, further supporting the immunocytochemical evidence that the newt homologs of these keratins are expressed in blastemal cells. This is the first demonstration of keratin expression in mesenchymal progenitor cells in an adult animal.     

The combined effects of dopamine (DA) and the DA antagonists EGYT-2509, chlorpromazine and haloperidol on the kidney function

In anaesthetized dogs renal function was investigated in four successive 20-min periods in four experimental series. (1) In the first series following the first period (serving as control) 2.5 micrograms/kg/min of dopamine (DA) dissolved in 0.5 ml/min of Ringer's solution was infused into the left renal artery (period 2), than during periods 3 and 4. It was found that first (period 2) and second (period 3) doses of DA induced a significant decrease of about 20-30% in renal vascular resistance, and an increase of about 15-25% in renal blood flow. At the same time, systemic arterial blood pressure fell by 10%. The other investigated parameters of the left kidney (Cinulin, CPAH, sodium, potassium and water excretion) did not differ from the respective parameters of the intact right kidney. (2) In the second experimental series following the first period (prior to period 2) 1.0 mg/kg of the DA antagonist EGYT 2509 was administered intravenously. Prior to the period 3 again 1.0 mg/kg of EGYT 2509 and prior to period 4 2.0 mg/kg of EGYT 2509 was given intravenously. During periods 2 through 4 2.5 micrograms/kg/min of DA was infused into the left renal artery. It could be ascertained that EGYT 2509 abolished the renal effects of DA while not inducing any decrease in arterial blood pressure. (3) In the third experimental series, following the control period, prior to periods 2,3 and 4, 1.0 mg/kg, 1.0 mg/kg and 2.0 mg/kg chlorpromazine respectively, was administered i.v. followed by the infusion of DA into the left renal artery. After the administration of chlorpromazine arterial blood pressure and renal vascular resistance fell concomitantly and DA failed to induce any further changes in these parameters. According to our experiments chlorpromazine abolishes the effect of DA on kidney function. (4) In the fourth series, prior to DA infusion the dogs were given 0.5 mg/kg (period 2) then again 0.5 mg/kg and finally 1.0 mg/kg of haloperidol intravenously. Haloperidol decreased arterial blood pressure as well as renal vascular resistance, thus renal blood flow did not change. Renal blood flow could then be increased by DA infused into the left renal artery. It seems that haloperidol could not abolish the vascular effects of DA in the kidney. Our experiments indicate that substance EGYT 2509 possesses the most marked dopaminergic antagonistic effect, chlorpromazine had also been effective, while haloperidol had proved to be practically ineffective.     

Evidence that the nerve controls molecular identity of progenitor cells for limb regeneration

Adult urodele amphibians can regenerate their limbs after amputation by a process that requires the presence of axons at the amputation plane. Paradoxically, if the limb develops in the near absence of nerves (the 'aneurogenic' limb) it can subsequently regenerate in a nerve-independent fashion. The growth zone (blastema) of regenerating limbs normally contains progenitor cells whose division is nerve-dependent. A monoclonal antibody that marks these nerve-dependent cells in the normal blastema does not stain the mesenchymal cells of developing limb buds and only stains the amputated limb bud when axons have reached the plane of amputation. This report shows that the blastemal cells of the regenerating aneurogenic limb also fail to react with the antibody in situ. These data suggest that the blastemal cells arising during normal regeneration have been altered by the nerve. This regulation may occur either at the time of amputation (when the antigen is expressed) or during development (when the limb is first innervated).     

The isolation and immunolocalization of iron-binding compounds produced by Gloeophyllum trabeum

Summary Low molecular weight iron-binding compounds are produced by the brown-rot fungus Gloeophyllum trabeum. These chelators may function in scavenging transition metals for fungal metabolism and extracellular enzyme production. Because of the low molecular mass of the chelate-metal complex (below 1000 Da), and the oxidizing potential of the bound transition metals, certain chelating compounds could also play a role in the early stages of cellulose depolymerization by brown-rot fungi. High-affinity iron-binding compounds were isolated and partially purified from both liquid cultures of the brown-rot Gloeophyllum trabeum and from infected wood. Chelating compounds purified by thin-layer chromatography were used to prepare specific antibodies. These antibodies were shown to detect the chelator in infected wood and liquid fungal cultures by enzyme-linked immunosorbent assay and could be used in immunotransmission electron microscopy to visualize the high-affinity iron-binding compounds in situ. Elucidating the physiological roles of fungal chelate-metal complexes and determining their function in lignocellulose depolymerization will help us to better understand the mechanism of wood biodegradation.Publication no. 1549 Maine Agricultural Experiment Station Offprint requests to: J. Jellison     

Prevention of anaphylactic death by macrophage blockade.

Data in the literature concerning the role of macrophages in anaphylaxis are contradictory. In the present study the effect of macrophage blockade induced by gadolinium chloride (GdCl3) on anaphylactic shock was investigated. Our observations show that GdCl3 prevents the lethal anaphylactic shock of mice sensitized to ovalbumin. GdCl3 given i.v. in a dose of 1 mg/100 g body weight 24 or 48 h before the elicitation of anaphylactic shock resulted in 90% survival, compared to the 43% survival in the control group. The same dose of this rare earth metal salt also greatly reduced the mortality in mice sensitized with ovalbumin containing Bordetella pertussis vaccine, and the symptoms of anaphylaxis including the accumulation of 5-hydroxytryptamine in the liver. Our results suggest that macrophages play an important role in anaphylaxis.