Distribution of stem-end rot on the canopy in ‘Hass’ avocado trees in two coastal areas in Peru

Stem-end rot (SER) of avocado is caused by several fungal species, and it is presented worldwide. This plant disease currently affects several avocado producer regions in Peru, causing fruit rot, impacting the industry negatively. Research about SER distribution in the canopy of avocado trees is limited. Thus, the present study aimed to compare which areas in the canopy are prone to have more SER in ‘Hass’ avocado harvested fruit in two different coastal areas in Peru. The experiment was conducted in the northern (Barranca) and southern (Cañete) of Lima. ‘Hass’Avocado fruits from both producer areas were collected to identify the causal agent; Lasiodiplodia theobromae was isolated from infected fruits. Identification was conducted based on morphological features and a partial DNA sequence of the translation elongation factor 1-α gene (tef1-α). The results showed that fruits inside the tree canopy were prone to have a higher disease incidence than the fruits located in the external site (P<0.001). Besides, internal-site fruits displayed a higher percentage of infected fruit for each grade disease (P<0.001) than external-site fruits, except for grade 0 (fruits without symptoms) and grade 1. Finally, the results suggested that the altitude where the fruit is positioned on the canopy could influence the incidence of SER, where fruits located in the high part revealed less incidence than the low section. The results are valuable for enhancing management strategies and avoiding postharvest loss of avocado fruits in our region.

NAD(H) Regulates the Permeability Transition Pore in Mitochondria through an External Site

The opening of the permeability transition pore (mPTP) in mitochondria initiates cell death in numerous diseases. The regulation of mPTP by NAD(H) in the mitochondrial matrix is well established; however, the role of extramitochondrial (cytosolic) NAD(H) is still unclear. We studied the effect of added NADH and NAD+ on: (1) the Ca2+-retention capacity (CRC) of isolated rat liver, heart, and brain mitochondria; (2) the Ca2+-dependent mitochondrial swelling in media whose particles can (KCl) or cannot (sucrose) be extruded from the matrix by mitochondrial carriers; (3) the Ca2+-dependent mitochondrial depolarization and the release of entrapped calcein from mitochondria of permeabilized hepatocytes; and (4) the Ca2+-dependent mitochondrial depolarization and subsequent repolarization. NADH and NAD+ increased the CRC of liver, heart, and brain mitochondria 1.5–2.5 times, insignificantly affecting the rate of Ca2+-uptake and the free Ca2+ concentration in the medium. NAD(H) suppressed the Ca2+-dependent mitochondrial swelling both in KCl- and sucrose-based media but did not induce the contraction and repolarization of swollen mitochondria. By contrast, EGTA caused mitochondrial repolarization in both media and the contraction in KCl-based medium only. NAD(H) delayed the Ca2+-dependent depolarization and the release of calcein from individual mitochondria in hepatocytes. These data unambiguously demonstrate the existence of an external NAD(H)-dependent site of mPTP regulation.

COVID-19

Diffuse pulmonary inflammation, endothelial inflammation, and enhanced thrombosis are cardinal features of coronavirus disease 2019 (COVID-19), the disease caused by the severe acute respiratory syndrome coronavirus 2. These features are reminiscent of several adverse reactions triggered by angiotensin II and opposed by angiotensin 1-7 , in many experimental models. Severe acute respiratory syndrome coronavirus 2 binds to ACE2 (angiotensin-converting enzyme 2) receptors and entries into the cell through the fusion of its membrane with that of the cell. Hence, it downregulates these receptors. The loss of ACE2 receptor activity from the external site of the membrane will lead to less angiotensin II inactivation and less generation of antiotensin 1-7 . In various experimental models of lung injury, the imbalance between angiotensin II overactivity and of antiotensin 1-7 deficiency triggered inflammation, thrombosis, and other adverse reactions. In COVID-19, such imbalance could play an important role in influencing the clinical picture and outcome of the disease. According to this line of thinking, some therapeutic approaches including recombinant ACE2, exogenous angiotensin 1-7 , and angiotensin receptor blockers seem particularly promising and are being actively tested.

Calcium and hydroxyapatite binding site of human vitronectin provides insights to abnormal deposit formation

The human blood protein vitronectin (Vn) is a major component of the abnormal deposits associated with age-related macular degeneration, Alzheimer’s disease, and many other age-related disorders. Its accumulation with lipids and hydroxyapatite (HAP) has been demonstrated, but the precise mechanism for deposit formation remains unknown. Using a combination of solution and solid-state NMR experiments, cosedimentation assays, differential scanning fluorimetry (DSF), and binding energy calculations, we demonstrate that Vn is capable of binding both soluble ionic calcium and crystalline HAP, with high affinity and chemical specificity. Calcium ions bind preferentially at an external site, at the top of the hemopexin-like (HX) domain, with a group of four Asp carboxylate groups. The same external site is also implicated in HAP binding. Moreover, Vn acquires thermal stability upon association with either calcium ions or crystalline HAP. The data point to a mechanism whereby Vn plays an active role in orchestrating calcified deposit formation. They provide a platform for understanding the pathogenesis of macular degeneration and other related degenerative disorders, and the normal functions of Vn, especially those related to bone resorption.

The effect of heteroatoms in carbonaceous surfaces: computational analysis of H chemisorption on to a PANH and Si-doped PAH

ABSTRACT In this work, we studied the effect of a heteroatom (nitrogen and silicon) inside the main skeleton of the carbonaceous surface in the H chemisorption reaction. The process taking place on to an N-doped polycyclic aromatic hydrocarbon (PAH), known as PANHs, shows differences in the energetic parameters only when the process is carried out on to the N atom. When N is located in an external site of the surface, the process is barrierless, whereas if N is in an internal position of the surface the activation energy drastically increases. The aromaticity of these N-doped systems does not change much concerning pristine coronene. In a Si-doped PAHs, the chemisorption on to the Si atom takes place in the absence of activation energy, regardless the position of Si on the surface. Moreover, the adsorption on to their neighbour carbon atoms is carried out with lower activation energies than those found in the reaction on to pristine PAH, indicating that the presence of silicon atoms in the surface favours H chemisorption. This might be due to a loss of aromaticity on the surface. In both cases, the reactions become significantly more exoenergetic. Finally, the presence of heteroatoms favours kinetically the reaction, where the rate coefficient of H2 formation process, calculated considering all of the sites of every PAH studied in this work, reaches a close value to the reported for diffuse interstellar medium and photodissociation regions ($R_{_{\mathrm{ H}\mathrm{ }_2}} = 1 \times 10^{-17}$ cm3 s−1 at 40 K).

World-Ecological Satire: Peat, Brian O'Nolan, and the Irish Free State's Energy Regime

A world-ecological perspective of cultural production refuses a dualist conception of nature and society – which imagines nature as an external site of static outputs – and instead foregrounds the fact that human and extra-human natures are completely intertwined. This essay seeks to reinterpret the satirical writing of a canonical figure within the Irish literary tradition, Brian O'Nolan, in light of the energy history of Ireland, understood as co-produced by both human actors and biophysical nature. How does the energy imaginary of O'Nolan's work refract and mediate the Irish environment and the socio-ecological relations shaping the fuel supply-chains that power the Irish energy regime dominant under the Irish Free State? I discuss the relationship between peat as fuel and Brian O'Nolan's pseudonymous newspaper columns, and indicate how questions about energy regimes and ecology can lead us to read his Irish language novel An Béal Bocht [The Poor Mouth] (1941) in a new light. The moments I select and analyze from O'Nolan's output feature a kind of satire that exposes the folly of separating society from nature, by presenting an exaggerated form of the myth of nature as an infinite resource.

Equilibrium geometries, electronic structure and magnetic properties of ConSn (n = 1–12) clusters from density functional calculations

Equilibrium geometries, relative stabilities, electronic stabilities and magnetic properties of Co[Formula: see text]Sn ([Formula: see text] = 1–12) clusters have been systematically investigated by using relativistic all-electron density functional theory with generalized gradient approximation. The results indicated that the lowest-energy structures of Co[Formula: see text]Sn ([Formula: see text] = 1–5, 7, 9 and 10) clusters are similar to those of corresponding Co[Formula: see text] clusters. As for Co6Sn, Co8Sn, Co[Formula: see text]Sn and Co[Formula: see text]Sn clusters, the most stable structures give rise to a geometry reconstruction. In the low-lying structures of Co[Formula: see text]Sn ([Formula: see text] = 1–12) clusters, tin impurity prefers to occupy the external site. The second-order difference energy of the ground-state Co[Formula: see text]Sn ([Formula: see text] = 1–12) clusters shows a pronounced odd–even oscillation with the number of Co atoms, and the clusters exhibit higher stability at [Formula: see text] = 5. Compared with corresponding pure Co[Formula: see text] clusters, the total magnetic moment of the Co[Formula: see text]Sn clusters reduces with 1, 3 and 5 [Formula: see text], respectively. The different magnetic changes of the tin doped Co clusters are analyzed in detail based on the magnetism coupling, density of state and hybridization between cobalt and tin atoms.

Hydroisomerization of Biomass Derived n-Hexadecane Towards Diesel Pool: Effect of Selective Removal External Surface Sites from Pt/ZSM-22

Influence of dealumination of zeolite ZSM-22 (Si/Al ratio of 45) by treating it with oxalic acid on its catalytic performance in n-hexadecane hydroisomerization reaction was studied. This reaction is an attempt in the direction of green and sustainable source of diesel via improving the cold-flow properties of deoxygenated vegetable oils. Pt (0.5 wt%) on ZSM-22 treated with 1 M oxalic acid afforded highest yields of the mono-branched paraffins. This improved is attributed to selective removal of active sites on external surface of zeolite crystals (responsible for undesired cracking reactions) using the bulkier dealuminating agent, oxalic acid. Thus, pore-mouth key-lock mechanism was brought to play the role to cause high selectivity to mono-branched isomers. Preferential external site deactivation was inferred from mesitylene cracking results. Effects of operating parameters such as temperature, and space velocity on product distribution also were studied. Also, kinetics of the reactions involved too has been in brief reported.

Noncompetitive blocking of human GLUT1 hexose transporter by methylxanthines reveals an exofacial regulatory binding site

Glucose transporter (GLUT)1 has become an attractive target to block glucose uptake in malignant cells since most cancer cells overexpress GLUT1 and are sensitive to glucose deprivation. Methylxanthines are natural compounds that inhibit glucose uptake; however, the mechanism of inhibition remains unknown. Here, we used a combination of binding and glucose transport kinetic assays to analyze in detail the effects of caffeine, pentoxifylline, and theophylline on hexose transport in human erythrocytes. The displacement of previously bound cytochalasin B revealed a direct interaction between the methylxanthines and GLUT1. Methylxanthines behave as noncompetitive blockers (inhibition constant values of 2–3 mM) in exchange and zero- trans efflux assays, whereas mixed inhibition with a notable uncompetitive component is observed in zero- trans influx assays (inhibition constant values of 5–12 mM). These results indicate that methylxanthines do not bind to either exofacial or endofacial d-glucose-binding sites but instead interact at a different site accessible by the external face of the transporter. Additionally, infinite- cis exit assays (Sen-Widdas assays) showed that only pentoxifylline disturbed d-glucose for binding to the exofacial substrate site. Interestingly, coinhibition assays showed that methylxanthines bind to a common site on the transporter. We concluded that there is a methylxanthine regulatory site on the external surface of the transporter, which is close but distinguishable from the d-glucose external site. Therefore, the methylxanthine moiety may become an attractive framework for the design of novel specific noncompetitive facilitative GLUT inhibitors.

XQuery Injection

We all know (and worry) about SQL injection, but should we also worry about XQuery injection? With the power of extension functions and the implementation of XQuery update features, the answer is clearly yes! We will see how an attacker can send information to an external site or erase a collection through XQuery injection on a naive and unprotected application using the eXist-db REST API. That's the bad news... The good news is that it's quite easy to protect your application from XQuery injection after this word of warning. We'll discuss a number of simple techniques (literal string escaping, wrapping values into elements or moving them out of queries in HTTP parameters) and see how to implement them in different environments covering traditional programming languages, XSLT, XForms and pipeline languages.