3,4-Dehydro-L-proline Induces Programmed Cell Death in the Roots of Brachypodium distachyon

As cell wall proteins, the hydroxyproline-rich glycoproteins (HRGPs) take part in plant growth and various developmental processes. To fulfil their functions, HRGPs, extensins (EXTs) in particular, undergo the hydroxylation of proline by the prolyl-4-hydroxylases. The activity of these enzymes can be inhibited with 3,4-dehydro-L-proline (3,4-DHP), which enables its application to reveal the functions of the HRGPs. Thus, to study the involvement of HRGPs in the development of root hairs and roots, we treated seedlings of Brachypodium distachyon with 250 µM, 500 µM, and 750 µM of 3,4-DHP. The histological observations showed that the root epidermis cells and the cortex cells beneath them ruptured. The immunostaining experiments using the JIM20 antibody, which recognizes the EXT epitopes, demonstrated the higher abundance of this epitope in the control compared to the treated samples. The transmission electron microscopy analyses revealed morphological and ultrastructural features that are typical for the vacuolar-type of cell death. Using the TUNEL test (terminal deoxynucleotidyl transferase dUTP nick end labelling), we showed an increase in the number of nuclei with damaged DNA in the roots that had been treated with 3,4-DHP compared to the control. Finally, an analysis of two metacaspases’ gene activity revealed an increase in their expression in the treated roots. Altogether, our results show that inhibiting the prolyl-4-hydroxylases with 3,4-DHP results in a vacuolar-type of cell death in roots, thereby highlighting the important role of HRGPs in root hair development and root growth.     

Chloroquine-Induced Accumulation of Autophagosomes and Lipids in the Endothelium

Chloroquine (CQ) is an antimalarial drug known to inhibit autophagy flux by impairing autophagosome–lysosome fusion. We hypothesized that autophagy flux altered by CQ has a considerable influence on the lipid composition of endothelial cells. Thus, we investigated endothelial responses induced by CQ on human microvascular endothelial cells (HMEC-1). HMEC-1 cells after CQ exposure were measured using a combined methodology based on label-free Raman and fluorescence imaging. Raman spectroscopy was applied to characterize subtle chemical changes in lipid contents and their distribution in the cells, while the fluorescence staining (LipidTox, LysoTracker and LC3) was used as a reference method. The results showed that CQ was not toxic to endothelial cells and did not result in the endothelial inflammation at concentrations of 1–30 µM. Notwithstanding, it yielded an increased intensity of LipidTox, LysoTracker, and LC3 staining, suggesting changes in the content of neutral lipids, lysosomotropism, and autophagy inhibition, respectively. The CQ-induced endothelial response was associated with lipid accumulation and was characterized by Raman spectroscopy. CQ-induced autophagosome accumulation in the endothelium is featured by a pronounced alteration in the lipid profile, but not in the endothelial inflammation. Raman-based assessment of CQ-induced biochemical changes offers a better understanding of the autophagy mechanism in the endothelial cells.     

FastFabric: Scaling hyperledger fabric to 20 000 transactions per second

Blockchain technologies are expected to make a significant impact on a variety of industries. However, one issue holding them back is their limited transaction throughput, especially compared to established solutions such as distributed database systems. In this paper, we rearchitect a modern permissioned blockchain system, Hyperledger Fabric, to increase transaction throughput from 3000 to 20 000 transactions per second. We focus on performance bottlenecks beyond the consensus mechanism, and we propose architectural changes that reduce computation and I/O overhead during transaction ordering and validation to greatly improve throughput. Notably, our optimizations are fully plug‐and‐play and do not require any interface changes to Hyperledger Fabric.     

Disruption of Vector Host Preference with Plant Volatiles May Reduce Spread of Insect-Transmitted Plant Pathogens

Plant pathogens can manipulate the odor of their host; the odor of an infected plant is often attractive to the plant pathogen vector. It has been suggested that this odor-mediated manipulation attracts vectors and may contribute to spread of disease; however, this requires further broad demonstration among vector-pathogen systems. In addition, disruption of this indirect chemical communication between the pathogen and the vector has not been attempted. We present a model that demonstrates how a phytophathogen (Candidatus Liberibacter asiaticus) can increase its spread by indirectly manipulating the behavior of its vector (Asian citrus psyllid, Diaphorina citri Kuwayama). The model indicates that when vectors are attracted to pathogen-infected hosts, the proportion of infected vectors increases, as well as, the proportion of infected hosts. Additionally, the peak of infected host populations occurs earlier as compared with controls. These changes in disease dynamics were more important during scenarios with higher vector mortality. Subsequently, we conducted a series of experiments to disrupt the behavior of the Asian citrus psyllid. To do so, we exposed the vector to methyl salicylate, the major compound released following host infection with the pathogen. We observed that during exposure or after pre-exposure to methyl salicylate, the host preference can be altered; indeed, the Asian citrus psyllids were unable to select infected hosts over uninfected counterparts. We suggest mechanisms to explain these interactions and potential applications of disrupting herbivore host preference with plant volatiles for sustainable management of insect vectors.     

PD-L1 Inhibitors: Different Classes,Activities, and Mechanisms of Action

Targeting the programmed cell death protein 1/programmed cell death 1 ligand 1 (PD-1/PD-L1) interaction has become an established strategy for cancer immunotherapy. Although hundreds of small-molecule, peptide, and peptidomimetic inhibitors have been proposed in recent years, only a limited number of drug candidates show good PD-1/PD-L1 blocking activity in cell-based assays. In this article, we compare representative molecules from different classes in terms of their PD-1/PD-L1 dissociation capacity measured by HTRF and in vitro bioactivity determined by the immune checkpoint blockade (ICB) co-culture assay. We point to recent discoveries that underscore important differences in the mechanisms of action of these molecules and also indicate one principal feature that needs to be considered, which is the eventual human PD-L1 specificity.     

[ecosistema urbano]

Polish architecture tutors and critics Roman Rutkowski and Lukasz Wojciechowski identify a new kind of architecture in [ecosistema urbano]'s ingenious temporary tower pavilions for a sterile new housing estate in Madrid. Contributing power to the local electricity grid, these towers are explicitly designed to provide shelter from the unmediated heat of the harsh external environment through their cooling effect and in so doing to stimulate communal activities and events. Copyright © 2009 John Wiley & Sons, Ltd.