Identification of a potential antimicrobial peptide derived from Haliotis midae haemocyanin

Haliotis midae aquaculture within South Africa remains afflicted by infectious diseases. Understanding of how the abalone’s innate immune response functions is one of the greatest hindrances to assisting with the defence or detection of pathogenic attacks on farms. The multifunctional oxygen transporter haemocyanin was previously found to be upregulated in response to bacterial infection (Beltran 2015), indicating it may play a role in the defence response of Haliotis midae. The current knowledge regarding haemocyanin’s role in the abalone innate immune response is incomplete. A number of studies have been published that investigated haemocyanin’s potential as a broad spectrum antimicrobial peptide in many arthropod species. There has been only one study conducted in molluscs, which utilised synthetic peptides derived from a haemocyanin consensus sequence. In most organisms the haemocyanin protein is comprised of a string of eight roughly 50 kDa functional units (FU) annotated a-h. The current study determined the nucleotide sequence of the final four functional units on the C-terminal end of H. midae haemocyanin and examined the potential antimicrobial activity of the peptide product. The haliotisin coding sequence identified by Zhuang et al. (2015) was detected in FU-e of the H. midae haemocyanin and subcloned into an Escherichia coli expression vector for recombinant production of the peptide. This peptide showed some activity against Staphylococcus aureus and E. coli, suggesting it may function as an antimicrobial peptide. This study provides the first evidence that an antimicrobial peptide derived from the H. midae haemocyanin could be functioning as a component of the abalone innate immune response

The influence of social comparisons on cooperation and fairness

Social comparisons, that is, people’s tendency to compare their own behavior to that of other people, are an important driver of human behavior. People want to ‘keep up with the Joneses’ and they want to think of their own group as positively distinct compared to other groups. Intriguingly, most social comparisons do not affect people’s monetary payoffs, but, nevertheless, they greatly affect people’s decisions. Many important social outcomes depend on people’s willingness to implement fair decisions and cooperate, and the provision of social information offers a promising tool for increasing socially desirable outcomes. While some studies have shown reductions in energy consumption, when providing people with information about their neighbors’ energy savings, others were less successful. Unfortunately, thus, the psychological mechanisms underlying the impact of social comparisons on people’s fairness and cooperation decisions are still poorly understood. In a series of controlled economic laboratory experiments, this dissertation sets out to test the relevance of psychological theories of social comparisons in order to better understand cooperation and fairness decisions. The first study reported here tests the effectiveness of social comparisons between teams as a means of increasing cooperation within teams, when teams are aware of different returns to cooperation, e.g., because teams being compared have different stakes in maintaining cooperation. We show that comparisons between groups make people more sensitive to their team member’s free-riding behavior. Here the provision of social information fires back by focusing people on their personal rather than their groups’ positive distinctiveness. The second study investigates how people acquire social comparison information about other people’s fairness decisions. Particularly when the acquired information is made public, people strategically avoid information suggesting fair decisions, thus identify the desire to appear prosocial as a key driver in information acquisition. In the third study, we investigate how children acquire social comparison information, if this information determines their relative evaluation. Here we demonstrate that even children from about 6-7 years are already able to strategically acquire social comparisons, thereby managing their social image and inhibiting their preference for desirable social comparisons. In the fourth study, I investigate whether and how people desire to set an example for others by affecting the social information available to others via their own cooperation decisions. I find that, even if there are no monetary incentives for setting an example, people desire to set an example for others, particularly when social norms are made salient. In sum, this dissertation presents converging evidence for the opportunities and risks involved in leveraging the power of social comparisons to increase cooperation and fairness

One-shot reciprocity under error management is unbiased and fragile

The error management model of altruism in one-shot interactions provides an influential explanation for one of the most controversial behaviors in evolutionary social science. The model posits that one-shot altruism arises from a domain-specific cognitive bias that avoids the error of mistaking a long-term relationship for a oneshot interaction. One-shot altruism is thus, in an intriguingly paradoxical way, a form of reciprocity. We examine the logic behind this idea in detail. In its most general form the error management model is exceedingly flexible, and restrictions about the psychology of agents are necessary for selection to be well-defined. Once these restrictions are in place, selection is well defined, but it leads to behavior that is perfectly consistent with an unbiased rational benchmark. Thus, the evolution of one-shot reciprocity does not require an evoked cognitive bias based on repeated interactions and reputation. Moreover, in spite of its flexibility in terms of psychology, the error management model assumes that behavior is exceedingly rigid when individuals face a new interaction partner. Reciprocity can only take the form of tit-for-tat, and individuals cannot adjust their behavior in response to new information about the duration of a relationship. Zefferman (2014) showed that one-shot reciprocity does not reliably evolve if one relaxes the first restriction, and we show that the behavior does not reliably evolve if one relaxes the second restriction. Altogether, these theoretical results on one-shot reciprocity do not square well with experiments showing increased altruism in the presence of payoff-irrelevant stimuli that suggest others are watching. (C) 2016 Elsevier Inc. All rights reserved

The Memory System Engaged During Acquisition Determines the Effectiveness of Different Extinction Protocols

Previous research indicates that extinction of rodent maze behavior may occur without explicit performance of the previously required response. In latent extinction, confining an animal to a previously rewarded goal location without reinforcement is typically sufficient to produce extinction of maze learning. However, previous studies have not determined whether latent extinction may be successfully employed to extinguish all types of memory acquired in the maze, or whether only specific types of memory may be vulnerable to latent extinction. The present study examined whether latent extinction may be effective across two plus-maze tasks that depend on anatomically distinct neural systems. Adult male Long-Evans rats were trained in a hippocampus-dependent place learning task (experiment 1), in which animals were trained to approach a consistent spatial location for food reward. A separate group of rats were trained in a dorsolateral striatum-dependent response learning task (experiment 2), in which animals were trained to make a consistent egocentric body-turn response for food reward. Following training, animals received response extinction or latent extinction. For response extinction, animals were given the opportunity to execute the original running approach response toward the empty food cup. For latent extinction, animals were confined to the original goal locations with the empty food cup, thus preventing them from making the original running approach response. Results indicate that, relative to no extinction, latent extinction was effective at extinguishing memory in the place learning task, but remained ineffective in the response learning task. In contrast, typical response extinction remained very effective at extinguishing memory in both place and response learning tasks. The present findings confirm that extinction of maze learning may occur with or without overt performance of the previously acquired response, but that the effectiveness of latent extinction may depend on the type of memory being extinguished. The findings suggest that behavioral treatments modeled after response extinction protocols may be especially useful in alleviating human psychopathologies involving striatum-dependent memory processes (i.e. drug addiction and relapse)

Emotional arousal and multiple memory systems in the mammalian brain

Emotional arousal induced by stress and/or anxiety can exert complex effects on learning and memory processes in mammals. Recent studies have begun to link study of the influence of emotional arousal on memory with earlier research indicating that memory is organized in multiple systems in the brain that differ in terms of the “type” of memory they mediate. Specifically, these studies have examined whether emotional arousal may have a differential effect on the “cognitive” and stimulus-response “habit” memory processes sub-served by the hippocampus and dorsal striatum, respectively. Evidence indicates that stress or the peripheral injection of anxiogenic drugs can bias animals and humans toward the use of striatal-dependent habit memory in dual-solution tasks in which both hippocampal and striatal-based strategies can provide an adequate solution. A bias toward the use of habit memory can also be produced by intra-basolateral amygdala (BLA) administration of anxiogenic drugs, consistent with the well documented role of efferent projections of this brain region in mediating the modulatory influence of emotional arousal on memory. In some learning situations, the bias toward the use of habit memory produced by emotional arousal appears to result from an impairing effect on hippocampus-dependent cognitive memory. Further research examining the neural mechanisms linking emotion and the relative use of multiple memory systems should prove useful in view of the potential role for maladaptive habitual behaviors in various human psychopathologies

Amygdala and Emotional Modulation of Multiple Memory Systems

Stress and anxiety can either enhance or impair memory, and the direction of the effect partially depends on the type of memory being affected. Behavioral or pharmacological stressors typically impair cognitive memory mediated by the hippocampus, but enhance stimulus-response habit memory mediated by the dorsolateral striatum. Evidence also indicates that the effect of emotion on different kinds of memory critically depends on a modulatory role of the basolateral amygdala (BLA). BLA modulation of multiple memory systems may be achieved through its glutamatergic projections to other brain regions, which may enhance stress hormone activity, modulate competition between memory systems, and alter synaptic plasticity. The neurobiology underlying the emotional modulation of multiple memory systems may be relevant to understand the impact of emotional arousal on the development and expression of human psychopathologies characterized by maladaptive habitual behaviors (e.g., drug addiction and relapse)

The Effect of Substitution and Polymerization of 2,7-Divinylcarbazole-benzo-bis-thiadiazole on Optoelectronic Properties: A DFT Study

In this work, we present the study of the conjugated copolymers 2,7-divinylcabazole and benzo-bis-thiadiazole, by the DFT method using the base B3LYP/6-31G (d, p). To evaluate the properties of these systems, we performed structural optimization without geometric restriction. The NBO analysis was obtained by an energy calculation of the DFT-B3LYP method under the atomic base 6-31G (d, p) from the optimized geometries. Calculations of vibratory frequencies of all the structures studied show that they have minima (all frequencies are positive) on the TPES. In order to study the electronic and optical properties, we calculated the HOMO and LUMO energy levels as well as the band gap (Gap energy). The absorption wavelengths of each system were calculated by the TD-DFT method at the functional level WB97XD under the atomic base 6-31G (d, p). DOI: http://dx.doi.org/10.17807/orbital.V13I4.158

There Is More Than One Kind of Extinction Learning

The view that different kinds of memory are mediated by dissociable neural systems has received extensive experimental support. Dissociations between memory systems are usually observed during initial acquisition, consolidation, and retrieval of memory, however increasing evidence also indicates a role for multiple memory systems in extinction behavior. The present article reviews a recent series of maze learning experiments that provide evidence for a multiple memory systems approach to extinction learning and memory. Evidence is described indicating that: (1) the hippocampus and dorsolateral striatum (DLS) mediate different kinds of extinction learning; (2) the effectiveness of different extinction protocols depends on the kind of memory being extinguished; and (3) whether a neural system is involved in extinction is also determined by the extinction protocol and kind of memory undergoing extinction. Based on these findings, a novel hypothetical model regarding the role of multiple memory systems in extinction is presented. In addition, the relevance of this multiple memory systems approach to other learning paradigms involving extinction (i.e., extinction of conditioned fear) and for treating human psychopathologies characterized by maladaptive memories (e.g., drug addiction and relapse) is briefly considered

Análisis de la situación económica del sector agropecuario en el Municipio de Condega, II semestre 2015

La presente investigación se denomina “Análisis de la situación económica del sector agropecuario en el municipio de Condega, II semestre 2015”, la cual se divide en ocho capítulos que marcan el camino para la correcta consecución de los objetivos propuestos. El primer capítulo aborda de manera general antecedentes, planteamiento del problema y justificación de la investigación; en el segundo, se plantean los objetivos que delimitan el alcance del estudio. En el municipio no se han realizado estudios específicos para determinar en qué situación se encuentra la actividad agropecuaria, por lo que en este trabajo se pretende analizar el sector antes mencionado, específicamente como fue el comportamiento que se presentó durante el segundo periodo del año 201