Obligatory Interactions Research Articles

The role of connectivity in conservation planning for species with obligatory interactions: Prospects for future climate scenarios

AbstractClimate change may lead to range shifts, and barriers to such displacements may result in extirpations from previously suitable habitats. This may be particularly important in freshwater ecosystems that are highly fragmented by anthropogenic obstacles, such as dams and other smaller in‐stream barriers. Conservation planning in freshwaters should consider the dynamic effects of climate change and the ability of species to cope with it. In this study, we developed a framework for incorporating climate‐driven dispersal barriers into conservation planning taking into account the medium and long‐term impacts of climate change and species with obligatory interactions. Given that freshwater mussels (Bivalvia: Unionida) are a group of highly threatened organisms dependent on fish hosts to complete their larval development and dispersal, we used Marxan to prioritize areas for their joint conservation in the Iberian Peninsula as a case study. We tested two connectivity scenarios between current and future habitats, (i) unlimited dispersal capacity and (ii) dispersal constrained by artificial barriers, and also identified priority translocation areas for species that were unable to disperse. Accounting for the effects of climate change on species distributions allowed the identification of long‐term conservation areas, but disregarding artificial barriers to dispersal may lead to unrealistic solutions. Integrating the location of barriers allowed the identification of priority areas that are more likely to be colonized in the future following climatic shifts, although this resulted in an additional loss of six to eight features (~5%–7%) compared to solutions without dispersal constraints. Between 173 and 357 artificial barriers (~1.6%–3.3%) will potentially block species dispersal to irreplaceable planning units. Where removal of artificial barriers is unfeasible, conservation translocations may additionally cover up to eight additional features that do not meet conservation targets due to dispersal constraints. This study highlights the challenge of identifying protected areas to safeguard biodiversity under climate change.

Influence of Climate Change on Obligatory Interactions in the Ecosystem: Predicting the Future

Influence of Climate Change on Obligatory Interactions in the Ecosystem: Predicting the Future

“Lepidoptera Flies”, but Not Always…Interactions of Caterpillars and Chrysalis with Soil

Lepidoptera, an order of insects traditionally linked to the aerial habitat, are much more diverse in their living environment than the clichéd image we may have of them. The imago stage, which is the most visible in these insects, is not the one that has the most interaction with the environment (usually caterpillars) nor the one that lasts the longest (very often chrysalises). These two stages are often directly related to litter and soil, although only the interaction at the pupal stage seems to follow a phylogenetic logic with two independent evolutionary events for the preference with soil: Use of litter and the upper “O” horizon as protection against predation for the evolutionarily oldest Lepidoptera families, pupation at greater depths (up to 60 centimetres in extreme cases) for the most derived Lepidoptera families; this probably to take advantage of the thermal and moisture buffer provided by the soil. An estimate suggests that about 25% of lepidopteran species worldwide have more or less obligatory interactions with soil.

Features of the Supramolecular Cell-Genetic Organization of E. Coli in Engineering Aspects of Biotechnology

Recently, there has been a keen interest in the physicochemical features of self-organizing spatio-temporal, heteropolymer-supramolecular assemblies, in which the system of components of the fluctuation dynamics of surface protein groups is evolutionarily selected for the implementation of morphogenetic processes of ontogenesis.That is, evolution created chemical compounds, the exceptional organization of which ensured the fulfillment of the most complex and precise tasks.In this research, the bacterial cell ofE. coli was considered in the concept of supramolecular science, where, in accordance with the informational development program based on the principles of molecular recognition, phase ensembles appear, which are characterized by a certain organization, depending on the phase growth of the population culture. In this respect, proteomic super-molecular physicochemistry can be considered as physicochemical or molecular informatics.Arginine is of interest because almost all of its molecule is active and undergoes obligatory interactions both with DNA and with other histones and non-histones. The results of this study demonstrated the super-protein surface of supramolecular assemblies, the flexible system PPCС-E.coli, active zones, dynamics of continuity, positioning topologicalspatio-temporal Arg-protease-processing, local areas of the nucleoid system, and interrelations at the level of: Bp-liquid crystal-bacterioplasma; NsCo-fragile, PsCo-tightly bound to the cell remainder; and in the Co-cell remainder itself. These data may be of practical interest in various engineering aspects of biotechnology.
 Keywords: arginine protease processing, supramolecules, E.coli, phase protein, super-molecules.

Mechanotransduction in trabecular meshwork cells requires obligatory interactions between TRPV4 channels, Rho signaling and focal adhesions

PurposeSustained exposure to mechanical forces triggers cellular remodeling that is essential to protect cells against mechanical stress. While this process is adaptive in the short term, chronic increases in cellular stiffness are paradigmatic of heart, lung, brain and eye diseases, however, the molecular mechanisms are not well understood. Here, we investigate the reciprocal interactions between cellular mechanotransducers (mechanosensitive ion channels and integrin‐based focal adhesions), calcium signaling, Rho signaling and actin remodeling in trabecular meshwork (TM) cells, which control intraocular pressure (IOP) via a feedback loop between IOP‐induced tensile stretch, cell stiffness and contractility. This process drives vision loss in glaucoma but the mechanisms are unknown.MethodsJuxtacanalicular and corneoscleral human TM cells were stimulated with biaxial strain (6–12%) for 1–24 hours in the presence of agonists/blockers of mechanosensitive channels, calcium chelators and/or Rho kinase inhibitors. [Ca2+] levels in TM cells were measured using optical imaging or electrophysiology. Live imaging cells were transfected mApple:actin or mCherry:actin. mRNA and protein levels of cytoskeletal, ECM and focal adhesion molecules were determined with qRT‐PCR, Western blot and immunostaining.ResultsExposure to strain and targeted activation of TRPV4 resulted in dramatic increase in F‐actin polymerization, which required calcium influx via TRPV4 channels. Stretch time‐dependently upregulated the transcript and protein levels of multiple focal adhesion (FA) proteins that included paxillin, focal adhesion kinase (FAK) and zyxin, an effect that was associated with phosphorylation of FA adapter/anchoring proteins and their translocation between cytoskeletal and membrane locations. Stretch‐induced, Rho‐dependent actin polymerization was downstream from TRPV4 channel activation and visualized as increased formation of stress fibers, however, not all of the intermediary steps were Ca2+‐dependent. Moreover, mechanical stress increased the size of FAs, facilitated vinculin colocalization with pFAK, and triggered zyxin relocation in a Ca2+‐dependent manner. Suppression of mechanotransduction mechanisms reduced actin polymerization, decreased cell contractility and increased fluid outflow.Summary/conclusionWe identified TRPV4 channels as key drivers of strain‐dependent cellular remodeling in the TM, and showed that this process plays a fundamental role in IOP regulation. TRPV4‐mediated Ca2+ influx was required to drive mechanoreciprocity – force‐dependent remodeling of FA and actin – to adapt the cells to mechanical stress. This time‐dependent mechanism appears to be required for the dynamic sensing of membrane strain and its role in adjusting steady‐state IOP. In glaucoma, this process is derailed by chronic increases in actin polymerization and TM stiffness that compromise fluid outflow from the anterior eye.Support or Funding InformationAcknowledgmentsFunding sourceThis work was supported by NIH (RO1EY027920, RO1EY022076, P30EY014800), Glaucoma Research Foundation and unrestricted grants from Research to Prevent Blindness to the Moran Eye Institute at the University of Utah.

A qualitative research on organizational peace in schools

The concept of organisational peace is a dynamic situation that can develop through open communication, whose main elements are justice, trust and goodwill, and affect the peace and happiness of individuals. Organisational peace consists of two dimensions such as ‘internal organisational peace’ and ‘external organisational peace’. ‘Internal organisational peace’, which is formed by relations and conditions within the organisation itself, is influenced by four factors such as individual, organisational, managerial and job characteristics. The ‘external organisational peace’, which is formed by the organisation's relations with others, stems from the direct–indirect, optional or obligatory interactions of the organisation. External organisational peace is influenced by five factors such as hierarchical relations, close environment, other organisations, society and global relations. This research is the first study that provides a conceptual framework for the concept of organisational peace and examines the concept of organisational peace empirically. The aim of this study is to determine the views of teachers in the ‘internal organisational peace’ dimension in schools. The research was carried out in the phenomenological design of qualitative research methods. The study group consisted of 10 teachers selected by the criterion sampling method. Teachers explain the concept of organisational peace with happiness, common goals, cooperation, justice, comfort, democratic values, harmony, respect and healthy communication. Factors that promote ‘internal organisational peace’ are positive personality, job satisfaction, fair practices, effective organisational communication, competencies of managers and good physical conditions of the job. Factors that prevent ‘internal organisational peace’ are negative personality, violent behaviour, unfair management, closed communication and bad physical conditions of the job.
 Keywords: Organisational peace, school, Turkey.

Incorporating biotic interactions in the distribution models of African wild silk moths (Gonometa species, Lasiocampidae) using different representations of modelled host tree distributions

AbstractBiotic interactions influence species niches and may thus shape distributions. Nevertheless, species distribution modelling has traditionally relied exclusively on environmental factors to predict species distributions, while biotic interactions have only seldom been incorporated into models. This study tested the ability of incorporating biotic interactions, in the form of host plant distributions, to increase model performance for two host‐dependent lepidopterans of economic interest, namely the African silk moth species, Gonometa postica and Gonometa rufobrunnea (Lasiocampidae). Both species are dependent on a small number of host tree species for the completion of their life cycle. We thus expected the host plant distribution to be an important predictor of Gonometa distributions. Model performance of a species distribution model trained only on abiotic predictors was compared to four species distribution models that additionally incorporated biotic interactions in the form of four different representations of host plant distributions as predictors. We found that incorporating the moth–host plant interactions improved G. rufobrunnea model performance for all representations of host plant distribution, while for G. postica model performance only improved for one representation of host plant distribution. The best performing representation of host plant distribution differed for the two Gonometa species. While these results suggest that incorporating biotic interactions into species distribution models can improve model performance, there is inconsistency in which representation of the host tree distribution best improves predictions. Therefore, the ability of biotic interactions to improve species distribution models may be context‐specific, even for species which have obligatory interactions with other organisms.

Indirect reciprocity with optional interactions.

Indirect reciprocity is a mechanism for the evolution of cooperation that is relevant for prosocial behavior among humans. Indirect reciprocity means that my behavior towards you also depends on what you have done to others. Indirect reciprocity is associated with the evolution of social intelligence and human language. Most approaches to indirect reciprocity assume obligatory interactions, but here we explore optional interactions. In any one round a game between two players is offered. A cooperator accepts a game unless the reputation of the other player indicates a defector. For a game to take place, both players must accept. In a game between a cooperator and a defector, the reputation of the defector is revealed to all players with probability Q. After a sufficiently large number of rounds the identity of all defectors is known and cooperators are no longer exploited. The crucial condition for evolution of cooperation can be written as hQB>1, where h is the average number of rounds per person and B=(b/c)-1 specifies the benefit-to-cost ratio. We analyze both stochastic and deterministic evolutionary game dynamics. We study two extensions that deal with uncertainty: hesitation and malicious gossip.

Audiovisual Temporal Integration of Speech and Gesture

The relation between speech and gestures is a topic of vigorous research in language comprehension and production. Recent studies indicate that speech and gestures are integrated in language comprehension (Kelly, Özyürek, & Maris, 2010) with mutual and obligatory interactions (Kita & Özyürek, 2003). This hypothesis is also supported by neurophysiological findings on the integration of speech and gestures (Willems, Özyürek, & Hagoort, 2007). In the present study, using two behavioral tasks, we further investigated the integration of speech and gesture by focusing on the ‘unity effect’ (the perception of two or more sensory signals with spatiotemporal contiguity and semantic/informational relatedness is unified into a multisensory whole; e.g., Vatakis & Spence, 2007) from the multisensory literature. In particular, we manipulated the levels of semantic relatedness between speech and gestures. In Experiment 1, we presented a series of dynamic iconic gestures (i.e., “cut”, “saw”, “write”) with the respective auditory speech. We manipulated semantic congruency through three conditions: congruent, weakly incongruent (e.g., “cut” with “saw”), and strongly incongruent (e.g., “cut” or “saw” with “write”). Participants performed a speeded discrimination task of unimodal (audio or visual) and multimodal conditions by detection of two target gestures (e.g., respond when you see, hear, or both “cut” and “saw”; all stimulus combinations where tested in a blocked format). Analysis of the reaction times (RTs) revealed shorter RTs, as expected, for the multimodal congruent cases as compared to the unimodal and incongruent conditions presented. In Experiment 2, participants performed an unspeeded temporal order judgment task (TOJ). For the TOJ task the above mentioned conditions were presented with a set of stimulus onset ansynchronies (±541, ±333, ±208, ±125, and 0ms). Analysis of the just noticeable difference (JND) showed higher JNDs and, thus, worse performance for the congruent as compared to the incongruent condition. Both experiments, therefore, confirmed, for the first time, the unity effect in speech-gesture pairings, as well as the facilitation effect of semantic relatedness on the integration of speech and gestures. Overall, the present study confirms the hypothesis of integration between speech and iconic gestures, opening new pathways to research on multisensory and temporal relationships between the two communicative signals.

Consequences of past climate change for species engaged in obligatory interactions

Obligatory interactions between species are fundamental to ecosystem functioning and are expected to be particularly sensitive to climate change. Although the effect of past and current climate changes on individual species has been thoroughly investigated, their effect on obligatory interactions has been overlooked. In this review, we present predictions about the effects of climate change on obligatory interactions and illustrate these predictions with examples from the literature. We focus on abrupt past climate change, especially during the Quaternary, because knowing past responses is useful for understanding and predicting the response of organisms and ecosystems to the current climate change. We also pinpoint the need for better time calibration of demographic events from genetic data, and for more studies focused on particularly suitable biological models. We hope that this review will stimulate interaction between the earth sciences and the life sciences on this timely topic.

Coevolution of partners and integrity of symbiotic systems

Symbioses are very beneficial models for studying the integrity of biosystems, which characterizes their structure-function orderliness and allows the partners to adequately respond to environmental changes. An analysis of various types of the plant-microbe and animal-microbe symbioses suggests that their integrity qualitatively increases during facultative and ecologically obligatory interactions of the partners, reaching its climax in the case of genetically obligatory interactions. Mathematical models enabled us to demonstrate that the functional integrity of N2-fixing legume-rhizobium symbiosis (concordance of the changes in the genotypic frequencies of the partners induced by environmental fluctuations) correlates with its ecological efficiency, which is increased by natural selection. The result is the establishment of tight regulatory feedbacks between the partners, leading to their genetic integration, which is referred to as “symbiogenome.” The genetic integrity of symbiosis determines its high evolutionary potential based on (a) the epigenetic inheritance of symbiotic characters by the host, implemented as a vertical transfer of either microsymbionts themselves or their genes and (b) interspecific altruism, which is associated with positive feedbacks between the partners and determines the ecological efficiency of mutualistic interactions. Realization of this potential leads to the deep genetic integration of initially independent partners, including their fusion into novel integral organisms.

Ant aggression and evolutionary stability in plant-ant and plant-pollinator mutualistic interactions

Mutualistic partners derive a benefit from their interaction, but this benefit can come at a cost. This is the case for plant-ant and plant-pollinator mutualistic associations. In exchange for protection from herbivores provided by the resident ants, plants supply various kinds of resources or nests to the ants. Most ant-myrmecophyte mutualisms are horizontally transmitted, and therefore, partners share an interest in growth but not in reproduction. This lack of alignment in fitness interests between plants and ants drives a conflict between them: ants can attack pollinators that cross-fertilize the host plants. Using a mathematical model, we define a threshold in ant aggressiveness determining pollinator survival or elimination on the host plant. In our model we observed that, all else being equal, facultative interactions result in pollinator extinction for lower levels of ant aggressiveness than obligatory interactions. We propose that the capacity to discriminate pollinators from herbivores should not often evolve in ants, and when it does it will be when the plants exhibit limited dispersal in an environment that is not seed saturated so that each seed produced can effectively generate a new offspring or if ants acquire an extra benefit from pollination (e.g. if ants eat fruit). We suggest specific mutualism examples where these hypotheses can be tested empirically.

Two Sides of the Same Coin

Gesture and speech are assumed to form an integrated system during language production. Based on this view, we propose the integrated-systems hypothesis, which explains two ways in which gesture and speech are integrated—through mutual and obligatory interactions—in language comprehension. Experiment 1 presented participants with action primes (e.g., someone chopping vegetables) and bimodal speech and gesture targets. Participants related primes to targets more quickly and accurately when they contained congruent information (speech: “chop”; gesture: chop) than when they contained incongruent information (speech: “chop”; gesture: twist). Moreover, the strength of the incongruence affected processing, with fewer errors for weak incongruities (speech: “chop”; gesture: cut) than for strong incongruities (speech: “chop”; gesture: twist). Crucial for the integrated-systems hypothesis, this influence was bidirectional. Experiment 2 demonstrated that gesture’s influence on speech was obligatory. The results confirm the integrated-systems hypothesis and demonstrate that gesture and speech form an integrated system in language comprehension.

Detection of transient protein–protein interactions by bimolecular fluorescence complementation: The Abl‐SH3 case

Protein-protein interactions are essential in most biological processes. Many proteomic approaches have succeeded in the identification of strong and obligatory interactions but the study of weak and transient protein-protein interactions is still a challenge. The aim of the present study was to test the ability of bimolecular fluorescence complementation to detect and discriminate in vivo weak intracellular protein interactions. As a test case, the interaction of the SH3 domain from the c-Abl tyrosine kinase with both natural and designed targets has been chosen. The reassociation of functional yellow fluorescent protein (YFP) from its fragments requires previous binding between the SH3 domain and its partners; but once this occurs, the complex is trapped, turning transient SH3 interactions into stable, easily detectable ones. The method is very sensitive and can be implemented for proteomic analysis of weak protein interactions using flow cytometry. The fluorescence emission is dependent on the strength of the interaction, in such a way that it can be used, at least qualitatively, to screen for best binding candidates among similar proline-rich peptides. In addition, it is illustrated how this method can be used to gain structural insights into particular c-Abl SH3 interactions.

Effects of Teaching Early Interventionists to Use Discrete Trials During Ongoing Classroom Activities

This study evaluated the effects of a teacher-training package that included sequential components (activity-based intervention [ABI] and ABI with discrete trials) on the rate of instructional opportunities presented to young children with disabilities. Three teachers and three children participated. A multiple-probe design was used with four conditions: classroom baseline, ABI, ABI with discrete trials, and generalization. Although the rate of instruction increased during the ABI condition, substantial increases were not seen until teachers received instruction on how to organize and conduct instructional trials using a discrete trials format. Concurrent observations revealed that the percentage of intervals in which teachers engaged in obligatory interactions (those that required a response) and nonobligatory interactions (those that did not require a response) increased as the rate of instruction increased and that the amount of time teachers engaged children in interactions that were nondirective remained unchanged following the introduction of the discrete trials format. As the rate of instruction increased, child engagement either increased or stayed the same, and all three children showed a higher rate of independent correct responses to target learning objectives in the ABI with discrete trials condition. These findings suggest that an important ingredient in the successful application of systematic instructional procedures in classroom settings may be related to how proficient early interventionists are at organizing and conducting an instructional trial.

Analysis of finger extensor mechanism strains

Strains in the extensor mechanism of the finger were measured in a cadaver model using Hall-effect transducers. Several components of the mechanism were evaluated at different joint positions, with different intrinsic and extrinsic tendon loading conditions, and after creating a boutonnière deformity. Landsmeer's theory that predictable and obligatory interactions occur within the extensor mechanism during finger movement is strongly supported by our results. The concept of the Bunnell intrinsic-tightness test was confirmed. Results were consistent with clinical observations and current theories on the pathomechanics of claw and boutonnière deformities. Based on our experimental findings, we conclude that strain analysis is an effective method of evaluation of the extensor mechanism with potential for in vivo surgical applications.

Effects of cooperation on competitive systems

A persistence-extinction theory of coupled cooperative-competitive systems is developed for three dimension Lotka-Volterra systems. Model conclusions indicate, as intuitively expected, that protocooperation can be beneficial for all species in the community. An outcome that is, perhaps, unexpected is that a protocooperative species can drive a stable competitive community to extinction. The models are successively modified to include a hierarchy of obligatory interactions. Obligatory cooperation generally leads to an increased degree of extinction from the perspective that it is generally attained under weaker conditions and generally involves more species.