On the ecological approach to Information and control for roboticists

The ongoing and increasingly important trend in robotics to conceive designs that decentralize control is paralleled by currently active research paradigms in the study of perception and action. James Gibson’s ecological approach is one of these paradigms. Gibson’s approach emerged in part as a reaction to representationalist and computationalist approaches, which devote the bulk of their resources to the study of internal processes. The ecological approach instead focuses on constraints and ambient energy patterns in the animal‐environment coalition. The present article reviews how the emphasis on the environment by ecological psychologists has given rise to the concepts of direct perception, higher order information, active information pick up, informationbased control laws, prospective control, and direct learning. Examples are included to illustrate these concepts and to show how they can be applied to the construction of robots. Action is described as emergent and self‐organized. It is argued that knowledge about perception, action, and learning as it occurs in living organisms may facilitate the construction of robots, more obviously so if the aim is to construct (to some extent) biologically plausible robots.This material is based upon work supported by grant FFI2009‐13416‐C02‐02 of the Spanish Ministry of Science and Innovation

An improved method for the in vitro differentiation of Plasmodium falciparum gametocytes into ookinetes

<p>Abstract</p> <p>Background</p> <p>Ookinete is the form of the malaria parasite that invades the mosquito midgut epithelium to initiate sporogony. Differentiation of ingested gametocytes into ookinetes in the mosquito midgut lumen and subsequent interaction with the lumenal surface of the midgut epithelium in preparation for invasion is a complex and multi-stepped process. To facilitate the study of these events in detail it is necessary to produce sufficient numbers of pure, fully mature and functional ookinetes. However, production of even a small number of <it>Plasmodium </it><it>falciparum </it>ookinetes <it>in vitro </it>has proven to be a daunting task. Consequently, over the past four decades our collective understanding of the biology of this parasite form remains sorely deficient. This article reports on investigations of five different ookinete media, in an effort to improve the <it>in vitro </it>transformation efficiency of <it>P. falciparum </it>gametocytes into mature ookinetes and their infectivity of the mosquito midgut.</p> <p>Methods</p> <p>Five different ookinete media were evaluated for their ability to support the differentiation of gametocytes into gametes and further into mature stage V ookinetes. Moreover, infectivity of the <it>in vitro</it>-transformed ookinetes was evaluated by feeding them to vector mosquitoes and measuring their ability to traverse the midgut and form oocysts.</p> <p>Results</p> <p>One of the five media (medium E) was clearly superior in that the cultured ookinetes produced the largest number of oocysts when fed to mosquitoes. Key components were additions of human serum, human red blood cell lysate and mosquito pupal extract, resulting in the production of larger numbers of ookinetes able to develop into oocysts when fed to mosquitoes.</p> <p>Conclusion</p> <p>This simple and practical improvement over the prevailing methodology will facilitate the investigation of how this important human malaria parasite initiates its development in the mosquito and will contribute to the understanding of its transmission biology.</p

Dynamic Touch as Common Ground for Enactivism and Ecological Psychology

The main purpose of this article is to show that enactivism and ecological psychology share more aspects than is often recognized. Rather than debating about differences, commonalities between the approaches are illustrated with the example of dynamic touch. Dynamic touch is a form of touch that implies muscles and tendons and that allows the perception of hand-held objects that are wielded but not seen. Given that perceivers perform the wielding movements with effort, dynamic touch necessarily implies active exploration. The strength of dynamic touch as an example lies in the fact that it has been formalized and analyzed in detail at the level of the laws that govern the organism-environment system. The example provides empirically supported instantiations of sensorimotor contingencies, in enactivist terms, and of intentional exploration and information detection, in ecological terms. Moreover, dynamic touch is a practical example of the enactivist concepts of bringing-forth the world and sense-making. As a second purpose, we use the example of dynamic touch to clarify key concepts of the ecological approach. Specifically, we analyze the concepts of invariance and affordance, indicating the crucial difference between perceiving and actualizing affordances, and highlighting the importance of these concepts for the dialogue between enactivism and ecological psychology.2019-2

Hemolytic C-Type Lectin CEL-III from Sea Cucumber Expressed in Transgenic Mosquitoes Impairs Malaria Parasite Development

The midgut environment of anopheline mosquitoes plays an important role in the development of the malaria parasite. Using genetic manipulation of anopheline mosquitoes to change the environment in the mosquito midgut may inhibit development of the malaria parasite, thus blocking malaria transmission. Here we generate transgenic Anopheles stephensi mosquitoes that express the C-type lectin CEL-III from the sea cucumber, Cucumaria echinata, in a midgut-specific manner. CEL-III has strong and rapid hemolytic activity toward human and rat erythrocytes in the presence of serum. Importantly, CEL-III binds to ookinetes, leading to strong inhibition of ookinete formation in vitro with an IC50 of 15 nM. Thus, CEL-III exhibits not only hemolytic activity but also cytotoxicity toward ookinetes. In these transgenic mosquitoes, sporogonic development of Plasmodium berghei is severely impaired. Moderate, but significant inhibition was found against Plasmodium falciparum. To our knowledge, this is the first demonstration of stably engineered anophelines that affect the Plasmodium transmission dynamics of human malaria. Although our laboratory-based research does not have immediate applications to block natural malaria transmission, these findings have significant implications for the generation of refractory mosquitoes to all species of human Plasmodium and elucidation of mosquito–parasite interactions

Plasmodium sporozoite phospholipid scramblase interacts with mammalian carbamoyl-phosphate synthetase 1 to infect hepatocytes

After inoculation by the bite of an infected mosquito, Plasmodium sporozoites enter the blood stream and infect the liver, where each infected cell produces thousands of merozoites. These in turn, infect red blood cells and cause malaria symptoms. To initiate a productive infection, sporozoites must exit the circulation by traversing the blood lining of the liver vessels after which they infect hepatocytes with unique specificity. We screened a phage display library for peptides that structurally mimic (mimotope) a sporozoite ligand for hepatocyte recognition. We identified HP1 (hepatocyte-binding peptide 1) that mimics a ~50 kDa sporozoite ligand (identified as phospholipid scramblase). Further, we show that HP1 interacts with a ~160 kDa hepatocyte membrane putative receptor (identified as carbamoyl-phosphate synthetase 1). Importantly, immunization of mice with the HP1 peptide partially protects them from infection by the rodent parasite P. berghei. Moreover, an antibody to the HP1 mimotope inhibits human parasite P. falciparum infection of human hepatocytes in culture. The sporozoite ligand for hepatocyte invasion is a potential novel pre-erythrocytic vaccine candidate. © 2021, The Author(s).1

Performing oncological procedures during COVID-19 outbreak: a picture from an Italian cancer center

Aim: Since SARS-CoV-2 infection rapidly spread around the world, Italy has quickly become one of the most affected countries. Healthcare systems introduced strict infection control measures to ensure optimal care, especially in frail groups such as cancer patients (pts). This study investigated the efficacy of SARS-CoV-2 pre-procedure screening and whether COVID-19 influenced timely diagnosis and therapy. Methods: Data of oncological procedures of pts with confirmed or suspected cancer diagnosis, treated at Oncology Department or coming from Emergency Department of San Luigi Gonzaga Hospital between June 2020 and March 2021 were retrospectively collected. A nasopharyngeal swab (NPS) was performed in outpatients 24/48 h before procedures. Inpatients were tested by NPS before and after hospitalization. Results: Two hundred and twenty-one pts were included in this analysis. Median age was 73 years, males were 58%. Eastern Cooperative Oncology Group (ECOG) Performance Status was 0 or 1 in 88% of pts. The most frequent cancer type was lung cancer (57%). Stages IV were 77%. Two hundred and forty-three scheduled procedures were performed with diagnostic (n: 142; 58%), therapeutic (n: 55; 23%), and palliative (n: 46; 19%) intent. One hundred and four and 139 procedures were performed in out- and in-pts, respectively. Of the 234 NPS performed, 10 (4%) were positive. Two pts were infected during hospitalization, 8 in community. Most of them were asymptomatic, while only 2 had mild symptoms. Eight procedures (3%) were postponed, 1 cancelled, while 2 were performed in positive pts. Median time to resolution of the infection was 17 days (11–36). Median delay in the procedures was 25 days (14–55). Five pts started systemic treatment, after a median time of 37.5 days (13–57). Conclusions: SARS-CoV-2 infection led to the postponement of a small, but not negligible percentage of oncological procedures. However, the low infection rate observed suggests that structured screening for COVID-19 is critical for the best management of scheduled procedures during pandemic

Effect of marcaine, a myotoxic drug, on macromolecular synthesis in muscle

The effects of Marcaine (bupivacaine) on RNA and protein synthesis in skeletal muscle have been studied. The drug did not affect RNA synthesis by pieces of rat tibialis anterior at concentrations as high as 0.5% (w/v), nor did it affect cell-free transcription of calf thymus DNA by wheat germ RNA polymerase II. In contrast, Marcaine inhibited protein synthesis by muscle chunks, and also inhibited [3H]leucine incorporation by cell-free components prepared from muscle. Specifically, the drug significantly inhibited aminoacylation of muscle transfer RNA with the amino acids leucine, methionine, lysine and valine (50-90 per cent) at a concentration of 0.5% and also inhibited elongation of polypeptide chains at the same concentration. Marcaine (0.5%) also inhibited aminoacylation of tRNA in cell-free systems derived from rat liver and from murine myeloma RPC-20, but it did not inhibit as strongly as in skeletal muscle. Interestingly, 0.5% Marcaine had no effect on the acylation of tRNA with leucine, methionine, lysine or valine when cell-free components from Escherichia coli were used.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22783/1/0000338.pd

The glutathione biosynthetic pathway of Plasmodium is essential for mosquito transmission

1Infection of red blood cells (RBC) subjects the malaria parasite to oxidative stress. Therefore, efficient antioxidant and redox systems are required to prevent damage by reactive oxygen species. Plasmodium spp. have thioredoxin and glutathione (GSH) systems that are thought to play a major role as antioxidants during blood stage infection. In this report, we analyzed a critical component of the GSH biosynthesis pathway using reverse genetics. Plasmodium berghei parasites lacking expression of gamma-glutamylcysteine synthetase (γ-GCS), the rate limiting enzyme in de novo synthesis of GSH, were generated through targeted gene disruption thus demonstrating, quite unexpectedly, that γ-GCS is not essential for blood stage development. Despite a significant reduction in GSH levels, blood stage forms of pbggcs− parasites showed only a defect in growth as compared to wild type. In contrast, a dramatic effect on development of the parasites in the mosquito was observed. Infection of mosquitoes with pbggcs− parasites resulted in reduced numbers of stunted oocysts that did not produce sporozoites. These results have important implications for the design of drugs aiming at interfering with the GSH redox-system in blood stages and demonstrate that de novo synthesis of GSH is pivotal for development of Plasmodium in the mosquito