Why do leaf-tying caterpillars abandon their leaf ties?

Leaf-tying caterpillars act as ecosystem engineers by building shelters between overlapping leaves, which are inhabited by other arthropods. Leaf-tiers have been observed to leave their ties and create new shelters (and thus additional microhabitats), but the ecological factors affecting shelter fidelity are poorly known. For this study, we explored the effects of resource limitation and occupant density on shelter fidelity and assessed the consequences of shelter abandonment. We first quantified the area of leaf material required for a caterpillar to fully develop for two of the most common leaf-tiers that feed on white oak, Quercus alba. On average, Psilocorsis spp. caterpillars consumed 21.65 ± 0.67 cm2 leaf material to complete development. We also measured the area of natural leaf ties found in a Maryland forest, to determine the distribution of resources available to caterpillars in situ. Of 158 natural leaf ties examined, 47% were too small to sustain an average Psilocorsis spp. caterpillar for the entirety of its development. We also manipulated caterpillar densities within experimental ties on potted trees to determine the effects of cohabitants on the likelihood of a caterpillar to leave its tie. We placed 1, 2, or 4 caterpillars in ties of a standard size and monitored the caterpillars twice daily to track their movement. In ties with more than one occupant, caterpillars showed a significantly greater propensity to leave their tie, and left sooner and at a faster rate than those in ties as single occupants. To understand the consequences of leaf tie abandonment, we observed caterpillars searching a tree for a site to build a shelter in the field. This is a risky behavior, as 17% of the caterpillars observed died while searching for a shelter site. Caterpillars that successfully built a shelter traveled 110 ± 20 cm and took 28 ± 7 min to find a suitable site to build a shelter. In conclusion, leaf-tying caterpillars must frequently abandon their leaf tie due to food limitation and interactions with other caterpillars, but this is a costly behavior

Evidence based or person centered? An ontological debate

Evidence based medicine (EBM) is under critical debate, and person centered healthcare (PCH) has been proposed as an improvement. But is PCH offered as a supplement or as a replacement of EBM? Prima facie PCH only concerns the practice of medicine, while the contended features of EBM also include methods and medical model. I here argue that there are good philosophical reasons to see PCH as a radical alternative to the existing medical paradigm of EBM, since the two seem committed to conflicting ontologies. This paper aims to make explicit some of the most fundamental assumptions that motivate EBM and PCH, respectively, in order to show that the choice between them ultimately comes down to ontological preference. While EBM has a solid foundation in positivism, or what I here call Humeanism, PCH is more consistent with causal dispositionalism. I conclude that if there is a paradigmatic revolution on the way in medicine, it is first of all one of ontology

Functional independence of the protein translocation machineries in mitochondrial outer and inner membranes

The protein translocation machineries of the outer and inner mitochondrial membranes usually act in concert during translocation of matrix and inner membrane proteins. We considered whether the two machineries can function independently of each other in a sequential reaction. Fusion proteins (pF-CCHL) were constructed which contained dual targeting information, one for the intermembrane space present in cytochrome c heme lyase (CCHL) and the other for the matrix space contained in the signal sequence of the precursor of F1-ATPase beta-subunit (pF1 beta). In the absence of a membrane potential, delta psi, the fusion proteins moved into the intermembrane space using the CCHL pathway. In contrast, in the presence of delta psi they followed the pF1 beta pathway and eventually were translocated into the matrix. The fusion protein pF51-CCHL containing 51 amino acids of pF1 beta, once transported into the intermembrane space in the absence of a membrane potential, could be further chased into the matrix upon re-establishing delta psi. The sequential and independent movement of the fusion protein across the two membranes demonstrates that the translocation machineries act as distinct entities. Our results support a model in which the two translocation machineries can function independently of each other, but generally interact in a dynamic fashion to achieve simultaneous translocation across both membranes. In addition, the results provide information about the targeting sequences within CCHL. The protein does not contain a signal for retention in the intermembrane space; rather, it lacks matrix targeting information, and therefore is unable to undergo delta psi-dependent interaction with the protein translocation apparatus in the inner membrane

Ideology behind ecological design

[Abstract] The aim of this article is to investigate the messages that are carried by ecological design. More precisely under review are ecological products and movements which advertise their usage. One of these movements is called «Bright Green Environmentalism» and its aim is to introduce already existing solutions to environmental problems. For this scope they have quite well known web-journal called «Worldchanging» which promotes the usage of ecological and sustainable products and they have published a book called «Worldchanging: a practical guide to 21 century». The message which this movement is communicating is that it is not necessary to renounce modern comforts and consumerism while being ecological. They believe that the solution to environmental problems can be found in sustainable design. The journal «Worldchanging» is supposed to be a combination of «socially conscious capitalism» and idealism. They declare that their approach is at the same time the one of activists and the consumerists. It is possible to analyze this interesting combination of ideas from the viewpoint of ideology. Italian semiotician Ferruccio Rossi-Landi has classified the conceptions of ideology under eleven headings. In this paper we are going to analyze the case of Bright Green Environmentalism and try to discover under which one of these eleven types of ideology we could place it. Below we are going to approach the phenomena of commercial green design from semioethic viewpoint. Semioethic theory suggests that human beings should be thought of not as «res cognitas» but as «semiotic animals» because humans hold immense responsibility towards the surrounding world as they are able to reflect over their actions, plan and suspend or change them. The ability of imagination that allows us to feel for the others puts us also in a position of no alibis. The scope of semioethics is to unmask the hidden ideologies that surround us and which we ourselves help to create

Translocation and insertion of precursor proteins into isolated outer membranes of mitochondria

Nuclear-encoded proteins destined for mitochondria must cross the outer or both outer and inner membranes to reach their final sub- mitochondrial locations. While the inner membrane can translocate preproteins by itself, it is not known whether the outer membrane also contains an endogenous protein translocation activity which can function independently of the inner membrane. To selectively study the protein transport into and across the outer membrane of Neurospora crassa mitochondria, outer membrane vesicles were isolated which were sealed, in a right-side-out orientation, and virtually free of inner membranes. The vesicles were functional in the insertion and assembly of various outer membrane proteins such as porin, MOM19, and MOM22. Like with intact mitochondria, import into isolated outer membranes was dependent on protease-sensitive surface receptors and led to correct folding and membrane integration. The vesicles were also capable of importing a peripheral component of the inner membrane, cytochrome c heme lyase (CCHL), in a receptor-dependent fashion. Thus, the protein translocation machinery of the outer mitochondrial membrane can function as an independent entity which recognizes, inserts, and translocates mitochondrial preproteins of the outer membrane and the intermembrane space. In contrast, proteins which have to be translocated into or across the inner membrane were only specifically bound to the vesicles, but not imported. This suggests that transport of such proteins involves the participation of components of the intermembrane space and/or the inner membrane, and that in these cases the outer membrane translocation machinery has to act in concert with that of the inner membrane

A Novel Peptide-Based SILAC Method to Identify the Posttranslational Modifications Provides Evidence for Unconventional Ubiquitination in the ER-Associated Degradation Pathway.

The endoplasmic reticulum-associated degradation (ERAD) pathway is responsible for disposing misfolded proteins from the endoplasmic reticulum by inducing their ubiquitination and degradation. Ubiquitination is conventionally observed on lysine residues and has been demonstrated on cysteine residues and protein N-termini. Ubiquitination is fundamental to the ERAD process; however, a mutant T-cell receptor α (TCRα) lacking lysine residues is targeted for the degradation by the ERAD pathway. We have shown that ubiquitination of lysine-less TCRα occurs on internal, non-lysine residues and that the same E3 ligase conjugates ubiquitin to TCRα in the presence or absence of lysine residues. Mass-spectrometry indicates that WT-TCRα is ubiquitinated on multiple lysine residues. Recent publications have provided indirect evidence that serine and threonine residues may be modified by ubiquitin. Using a novel peptide-based stable isotope labeling in cell culture (SILAC) approach, we show that specific lysine-less TCRα peptides become modified. In this study, we demonstrate that it is possible to detect both ester and thioester based ubiquitination events, although the exact linkage on lysine-less TCRα remains elusive. These findings demonstrate that SILAC can be used as a tool to identify modified peptides, even those with novel modifications that may not be detected using conventional proteomic work flows or informatics algorithms

The Paradox of Local Participation in Forced Displacement and Resettlement Caused by the Development Process

This article is an investigation of the theoretical and empirical concept of local participation, as it is used in the field of development-induced forced displacement and relocation (in short, DFDR). Local participation has repeatedly proved to be relevant with respect to the decrease of the negative impacts caused by DFDR on the people involved. Paradoxically, people who contribute to this process with their very culture and means of existence - including their land - often end up in chronic poverty, despite their participation in local decision-making. It appears that this concept, which was developed precisely in order to protect persons affected by poverty and supporting them in their attempt to overcome this poverty, contributes nevertheless to the destruction of their local culture, which shows signs of "inside cracking".Hence the necessity to answer two questions: is the concept of local participation deceitful or is it used erroneously? Do we need to reinterpret and rethink the way the project is conceived, planned and executed, taking into account its crucial elements with respect to risks and compensations? This approach seems to me to constitute a way to overcome blockages and avoid considering negotiations as an inflexible, univocal, hierarchical relation between two parties blocked into anasymmetrical power game without any possibility to escape from it. I have used the example of the hydroelectric dam project in Zimapán, Mexico, as a starting point for an ethnographic discussion of local participation2

Structural Forecasts for the Danish Economy Using the Dynamic-AAGE Model

We describe how an applied dynamic general equilibrium model of the Danish economy has been developed to generate structural forecasts. The forecasts provide a microeconomic picture that is consistent with a macroeconomic scenario and the other inputs. We provide an overview of the inputs required to generate the forecasts and of the forecast methodology. Finally, we present aspects of the forecasting results.Research and Development/Tech Change/Emerging Technologies,