Differences between ranamargarin and other tachykinins in the stimulation of ion transport in frog skin

In frog skin, tachykinins stimulate ion transport by interaction with NK1-like receptors. The structural requirements of the peptide are the presence of the C-terminal sequence Phe-X-Gly-Leu-Met-NH₂ and at least one Pro residue in the N-terminal sequence. In this paper, we demonstrate that the C-terminal amino acid must be amidated but it can be different from Met, and that the sequence cannot be longer or shorter than 11–12 amino acids. Unexpectedly, Ranamargarin (14 amino acids, no Pro residue) increased the short circuit current value by 48 ± 0.3%. On the basis of considerable experimental evidence, we suggest that Ranamargarin interacts with a receptor different from those of other tachykinins.     

Donepezil structure-based hybrids as potential multifunctional anti-Alzheimer’s drug candidates

A new series of multifunctional hybrids, based on the structure of the donepezil (DNP) drug, have been developed and evaluated as potential anti Alzheimer’s disease (AD) agents. The rationale of this study was the conjugation of a benzylpiperidine/benzylpiperazine moiety with derivatives of bioactive heterocyclics (benzimidazole or benzofuran), to mimic the main structure of DNP and to endow the hybrids with additional relevant properties such as inhibition of amyloid beta (Aβ) peptide aggregation, antioxidant activity and metal chelation. Overall, they showed good activity for AChE inhibition (IC₅₀=4.0–30.0 μΜ) and moderate ability for inhibition of Aβ_1–42 self-mediated aggregation. The hybrids containing chelating groups showed improvement in the inhibition of Cu-induced Aβ₄₂ aggregation and the antioxidant capacity. Moreover, neuroprotective effects of these compounds were evidenced in neuroblastoma cells after Aβ_1–42 induced toxicity. Structure–activity relationship allowed the identification of some promising compounds and the main determinant structural features for the targeted properties.     

Kilogrid: a novel experimental environment for the Kilobot robot

We present the Kilogrid, an open-source virtualization environment and data logging manager for the Kilobot robot, Kilobot for short. The Kilogrid has been designed to extend the sensory-motor abilities of the Kilobot, to simplify the task of collecting data during experiments, and to provide researchers with a tool to fine-control the experimental setup and its parameters. Based on the design of the Kilobot and compatible with existing hardware, the Kilogrid is a modular system composed of a grid of computing nodes, or modules that provides a bidirectional communication channel between the Kilobots and a remote workstation. In this paper, we describe the hardware and software architecture of the Kilogrid system as well as its functioning to accompany its release as a new open hardware tool for the swarm robotics community. We demonstrate the capabilities of the Kilogrid using a 200-module Kilogrid, swarms of up to 100 Kilobots, and four different case studies: exploration and obstacle avoidance, site selection based on multiple gradients, plant watering, and pheromone-based foraging. Through this set of case studies, we show how the Kilogrid allows the experimenter to virtualize sensors and actuators not available to the Kilobot and to automatize the collection of data essential for the analysis of the experiments.     

Balancing exploitation of renewable resources by a robot swarm

Renewable resources like fish stock or forests should be exploited at a rate that supports regeneration and sustainability—a complex problem that requires adaptive approaches to maintain a sufficiently high exploitation while avoiding depletion. In the presence of oblivious agents that cannot keep track of all available resources—a frequent condition in swarm robotics—ensuring that the exploitation effort is correctly balanced is particularly challenging. Additionally, the possibility to exploit resources by multiple robots opens the way to focusing the effort either on a single or on multiple resources in parallel. This means that the swarm needs to collectively decide whether to remain cohesive or split among multiple resources, as a function of the ability of the available resources to replenish after exploitation. In this paper, we propose a decentralised strategy for a swarm of robots that adapts to the available resources and balances the effort among them, hence allowing to maximise the exploitation rate while avoiding to completely deplete the resources. A detailed analysis of the strategy parameters provides insights into the working principles and expected performance of the robot swarm.     

STAMINATE BLOOM DATE AND TEMPERATURE RESPONSES OF POLLEN GERMINATION AND TUBE GROWTH IN TWO WALNUT (JUGLANS) SPECIES

Pollen was collected from ten cultivars of Juglans regia and three cultivars of the later-blooming species, J. nigra. Extensive phenological data were available for these cultivars. Cultivars were chosen on the basis of staminate bloom date to include the earliest and latest blooming individuals available and a representative range throughout the bloom season. Mean staminate bloom dates for the cultivars examined covered a period of 46 days over which time mean daily temperatures rose 6 C. In order to determine if adaptations to temperature were expressed by the gametophyte generation, pollen was subjected to controlled temperatures from 5 to 40 C in 2 to 4 C increments and analyzed for germination percentages and pollen tube elongation. A positive relationship was found for pollen germination percentage and mean staminate bloom date such that earlier blooming individuals showed lower minimum temperature thresholds for germination, and optimum temperature for pollen germination was positively correlated with mean staminate bloom date. Differences in pollen tube growth, determined separately from hydration and germination responses, were less clear. Most J. regia clones had lower minium temperature thresholds for growth than the J. nigra clones, but there was no clear relationship to earliness of bloom within the species. No differences were discerned in optimum temperatures for pollen tube growth either between the two species or within species.     

Alteration of monocytic cell oxidative burst caused by methacrylic monomers present in dental materials: a chemiluminescence study.

Methacrylates are present in dental composite resins used in clinical practice. Methacrylates are photo-polymerized, but this reaction is never complete, so release of uncured monomers in the periapical tissues and in biological fluids may happen and, potentially, alter the repair of pulpal and of periapical lesions by interfering with local phagocytes. The aim of this study was the evaluation of the functional activity of the monocyte-macrophage system after incubation with methacrylic monomers. The oxidative burst of two cellular systems was analysed using the chemiluminescence technique. Data were collected and statistically analysed. Monomers were found to reduce the in vitro oxidative burst of phagocytes independently from their cytotoxicity. These findings demand further evaluation of the effects of oxidative burst alteration in monocyte-macrophage function and may prompt the inclusion of the described chemiluminescence test in biocompatibility preliminary studies of dental materials.     

Post-translational modifications of VDAC1 and VDAC2 cysteines from rat liver mitochondria

VDACs three isoforms (VDAC1, VDAC2, VDAC3) are integral proteins of the outer mitochondrial membrane whose primary function is to permit the communication and exchange of molecules related to the mitochondrial functions. We have recently reported about the peculiar over-oxidation of VDAC3 cysteines. In this work we have extended our analysis, performed by tryptic and chymotryptic proteolysis and UHPLC/High Resolution ESI-MS/MS, to the other two isoforms VDAC1 and VDAC2 from rat liver mitochondria, and we have been able to find also in these proteins over-oxidation of cysteines. Further PTM of cysteines as succination has been found, while the presence of selenocysteine was not detected. Unfortunately, a short sequence stretch containing one genetically encoded cysteine was not covered both in VDAC2 and in VDAC3, raising the suspect that more, unknown modifications of these proteins exist. Interestingly, cysteine over-oxidation appears to be an exclusive feature of VDACs, since it is not present in other transmembrane mitochondrial proteins eluted by hydroxyapatite. The assignment of a functional role to these modifications of VDACs will be a further step towards the full understanding of the roles of these proteins in the cell.