The IUCN Green Status of Species: A Call for Mediterranean Botanists to Contribute to This New Ambitious Effort

In the Mediterranean Basin, a critical focal point for the conservation of plant diversity, there has been a large increase in practical conservation actions for many plant species to prevent extinction and to improve their conservation status; quantifying the effectiveness of these initiatives in reversing species declines is urgently important. In 2021, the International Union for Conservation of Nature (IUCN) launched a new tool that allows the impact of conservation actions on plant species to be assessed. The Green Status of Species is a new set of metrics under the Red List of Threatened Species that assigns species to recovery categories, complementary to the classic extinction risk categories. Crucially, the Green Status of Species provides methods to evaluate the impact of past conservation, and the potential for future conservation impact, on species status and recovery in a standardized way. Considering the efforts made so far for the conservation of Mediterranean threatened plants, using the Green Status of Species would be highly useful to direct future conservation policies. We, therefore, encourage botanists and practitioners working on threatened plants in the Mediterranean area to use this new assessment tool to inform conservation and recovery programs

Structure-Based Optimization of a Non-\u3b2-lactam Lead Results in Inhibitors That Do Not Up-Regulate \u3b2-Lactamase Expression in Cell Culture

Bacterial expression of \u3b2-lactamases is the most widespread resistance mechanism to \u3b2 -lactam antibiotics. There is a pressing need for novel, non-\u3b2-lactam inhibitors of these enzymes. Our lead, compound 1, is chemically dissimilar to \u3b2 -lactams and is a noncovalent, competitive inhibitor of the enzyme. However, at 26 \u3bcM its activity is modest (Figure 1). Using the X-ray structure of the AmpC/1 complex as a template, 14 analogues were designed and synthesized. Among these, compound 10, had a Ki of 1 \u3bcM, 26-fold better than the lead. The structures of AmpC in complex with compound 10 and an analogue, compound 11, were determined by X-ray crystallography to 1.97 and 1.96 \uc5, respectively. Compound 10 was active in cell culture, reversing resistance to the third generation cephalosporin ceftazidime in bacterial pathogens expressing AmpC. In contrast to \u3b2-lactam-based inhibitors compound 10 did not up-regulate \u3b2-lactamase expression in cell culture but simply inhibited the enzyme expressed by the resistant bacteria. Its escape from this resistance mechanism derives from its dissimilarity to \u3b2 -lactam antibiotics

Structure-based discovery and in-parallel optimization of novelcompetitive inhibitors of thymidylate synthase

AbstractBackground:The substrate sites of enzymes are attractive targets for structurebased inhibitor design. Two difficulties hinder efforts to discover and elaborate new (nonsubstrate-like) inhibitors for these sites. First, novel inhibitors often bind at nonsubstrate sites. Second, a novel scaffold introduces chemistry that is frequently unfamiliar, making synthetic elaboration challenging.Results:In an effort to discover and elaborate a novel scaffold for a substrate site, we combined structure-based screening with in-parallel synthetic elaboration. These techniques were used to find new inhibitors that bound to the folate site of Lactobacillus casei thymidylate synthase (LcTS), an enzyme that is a potential target for proliferative diseases, and is highly studied. The available chemicals directory was screened, using a molecular-docking computer program, for molecules that complemented the three-dimensional structure of this site. Five high-ranking compounds were selected for testing. Activity and clocking studies led to a derivative of one of these, dansyltyrosine (Ki 65 μM. Using solid-phase in-parallel techniques 33 derivatives of this lead were synthesized and tested. These analogs are dissimilar to the substrate but bind competitively with it. The most active analog had a Ki of 1.3 μM. The tighter binding inhibitors were also the most specific for LcTS versus related enzymes.Conclusions:TS can recognize inhibitors that are dissimilar to, but that bind competitively with, the folate substrate. Combining structure-based discovery with in-parallel synthetic techniques allowed the rapid elaboration of this series of compounds. More automated versions of this approach can be envisaged

A tetrameric iron superoxide dismutase from the eucaryote Tetrahymena pyriformis.

Abstract An iron-containing superoxide dismutase has been purified from the protozoan Tetrahymena pyriformis. It has a molecular weight of 85,000 and is composed of four subunits of equal size. The tetramer contains 2.5 g atoms of ferric iron. Visible absorption and electron spin resonance spectra closely resemble those of other iron-containing superoxide dismutases. The amino acid sequence of the iron superoxide dismutase was determined. Each subunit is made up of 196 residues, corresponding to a molecular weight of 22,711. Comparison of the primary structure with the known sequences of other iron-containing superoxide dismutases reveals a relatively low degree of identity (33-34%). However, a higher percentage identity is found with mammalian manganese-containing superoxide dismutases (41-42%). The amino acid sequence is discussed in consideration of residues that may distinguish iron from manganese or dimeric from tetrameric superoxide dismutases

Enhancement of the Intermolecular Magnetic Exchange through Halogen···Halogen interactions in Bisadeninium Rhenium(IV) Salts

Two novel Re^IV salts of general formula [H₂ade]₂[Re^IVX₆]­X₂·4H₂O [H₂ade²⁺ = 9<i>H</i>-adenine-1,7-diium; X = Cl­(<b>1</b>) and Br­(<b>2</b>)] have been synthesized and magnetostructurally characterized. <b>1</b> and <b>2</b> are isostructural salts that crystallize in the orthorhombic system with space group <i>Fdd</i>2. Both compounds are made up of discrete mononuclear [Re^IVX₆]^2– and X^– anions and doubly protonated adenine cations. The six-coordinate rhenium­(IV) ion is bonded to six halide ligands [X = Cl (<b>1</b>) and Br (<b>2</b>)] in an octahedral geometry. Short intermolecular Re^IV–X···X–Re^IV interactions, as well as Re^IV–X···H–N­(H₂ade) and Re^IV–X···H–O_w hydrogen bonds, are present in the crystal lattice of <b>1</b> and <b>2</b>. Magnetic susceptibility measurements on polycrystalline samples of <b>1</b> and <b>2</b> in the temperature range 2.0–300 K show the occurrence of significant intermolecular antiferromagnetic interactions in both compounds, resulting in the observation of maxima in χ_M at ca. 6.0 (<b>1</b>) and 12.0 K (<b>2</b>). The larger spin delocalization from the Re^IV ion onto the peripheral bromide ligands when compared to the chloride ligands accounts for the enhancement of the magnetic exchange observed in <b>2</b>

The mass surface density in the local disk and the chemical evolution of the Galaxy

We have studied the effect of adopting different values of the total baryonic mass surface density in the local disk at the present time in a model for the chemical evolution of the Galaxy. We have compared our model results with the G-dwarf metallicity distribution, the amounts of gas, stars, stellar remnants, infall rate and SN rate in the solar vicinity, and with the radial abundance gradients and gas distribution in the disk. This comparison strongly suggests that the value of the total baryonic mass surface density in the local disk which best fits the observational properties should lie in the range 50-75 Msun pc-2, and that values outside this range should be ruled out.Comment: 6 pages, LaTeX, 3 figures, accepted for publication in the Astrophysical Journal, uses emulateapj.st

Hermetia illucens (L.) (Diptera: Stratiomyidae) Odorant Binding Proteins and Their Interactions with Selected Volatile Organic Compounds: An In Silico Approach

The black soldier fly (BSF), Hermetia illucens (Diptera: Stratiomyidae), has considerable global interest due to its outstanding capacity in bioconverting organic waste to insect biomass, which can be used for livestock, poultry, and aquaculture feed. Mass production of this insect in colonies requires the development of methods concentrating oviposition in specific collection devices, while the mass production of larvae and disposing of waste may require substrates that are more palatable and more attractive to the insects. In insects, chemoreception plays an essential role throughout their life cycle, responding to an array of chemical, biological and environmental signals to locate and select food, mates, oviposition sites and avoid predators. To interpret these signals, insects use an arsenal of molecular components, including small proteins called odorant binding proteins (OBPs). Next generation sequencing was used to identify genes involved in chemoreception during the larval and adult stage of BSF, with particular attention to OBPs. The analysis of the de novo adult and larval transcriptome led to the identification of 27 and 31 OBPs for adults and larvae, respectively. Among these OBPs, 15 were common in larval and adult transcriptomes and the tertiary structures of 8 selected OBPs were modelled. In silico docking of ligands confirms the potential interaction with VOCs of interest. Starting from the information about the growth performance of H. illucens on different organic substrates from the agri-food sector, the present work demonstrates a possible correlation between a pool of selected VOCs, emitted by those substrates that are attractive for H. illucens females when searching for oviposition sites, as well as phagostimulants for larvae. The binding affinities between OBPs and selected ligands calculated by in silico modelling may indicate a correlation among OBPs, VOCs and behavioural preferences that will be the basis for further analysis

High-fidelity quantum driving

The ability to accurately control a quantum system is a fundamental requirement in many areas of modern science such as quantum information processing and the coherent manipulation of molecular systems. It is usually necessary to realize these quantum manipulations in the shortest possible time in order to minimize decoherence, and with a large stability against fluctuations of the control parameters. While optimizing a protocol for speed leads to a natural lower bound in the form of the quantum speed limit rooted in the Heisenberg uncertainty principle, stability against parameter variations typically requires adiabatic following of the system. The ultimate goal in quantum control is to prepare a desired state with 100% fidelity. Here we experimentally implement optimal control schemes that achieve nearly perfect fidelity for a two-level quantum system realized with Bose-Einstein condensates in optical lattices. By suitably tailoring the time-dependence of the system's parameters, we transform an initial quantum state into a desired final state through a short-cut protocol reaching the maximum speed compatible with the laws of quantum mechanics. In the opposite limit we implement the recently proposed transitionless superadiabatic protocols, in which the system perfectly follows the instantaneous adiabatic ground state. We demonstrate that superadiabatic protocols are extremely robust against parameter variations, making them useful for practical applications.Comment: 17 pages, 4 figure

The electronic structure and dynamics of the excited triplet state of octaethylaluminum(III)-porphyrin investigated with advanced EPR methods

The photoexcited triplet state of octaethylaluminum(III)-porphyrin (AlOEP) was investigated by time-resolved Electron Paramagnetic Resonance, Electron Nuclear Double Resonance and Electron Spin Echo Envelope Modulation in an organic glass at 10 and 80 K. This main group element porphyrin is unusual because the metal has a small ionic radius and is six-coordinate with axial covalent and coordination bonds. It is not known whether triplet state dynamics influence its magnetic resonance properties as has been observed for some transition metal porphyrins. Together with density functional theory modelling, the magnetic resonance data of AlOEP allow the temperature dependence of the zero-field splitting (ZFS) parameters, D and E, and the proton AZZ hyperfine coupling (hfc) tensor components of the methine protons, in the zero-field splitting frame to be determined. The results provide evidence that the ZFS, hfc and spin–lattice relaxation are indeed influenced by the presence of a dynamic process that is discussed in terms of Jahn-Teller dynamic effects. Thus, these effects should be taken into account when interpreting EPR data from larger complexes containing AlOEP

Heart rate variability analysis during head-up tilt test predicts nitroglycerine-induced syncope

OBJECTIVE: The aim of this study was to determine whether or not heart rate variability (HRV) analysis during the first 20\u2005min of head-up tilt testing could predict whether patients will develop syncope after nitroglycerine administration. DESIGN: 64 patients with previous loss of consciousness underwent head-up tilt testing with the Italian protocol, which involves the administration of nitroglycerine after 20\u2005min of tilt. HRV parameters were analysed from 5\u2005min intervals selected during pretest supine rest (phase 1), the first 5\u2005min (phase 2) and the last 5\u2005min (phase 3) of passive 20\u2005min of tilting, prior to the administration of nitroglycerine. Differences in power (ms(2)) of the spectral components between the various phases of tilting were calculated for each patient and expressed as \u394. RESULTS: 20 patients (group 1, 9 women, mean age 43.2\ub124.5\u2005years) had a syncope during tilt testing after nitroglycerine, while the other 44 (group 2, 24 women, mean age 41\ub120.5\u2005years) did not. In group 1, the HRV spectral parameters high frequency (HF) and total power (TP) had a significant decrement from phases 2 to 3 (p=0.012 and 0.027, respectively), while in group 2 the average HF and TP values did not change. The \u394 of spectral parameters between phases 2 and 3 were able to differentiate between the two groups and to predict syncope after nitroglycerine administration (p<0.05). CONCLUSIONS: HRV analysis within the first 20\u2005min of passive tilting demonstrated that patients with nitroglycerine-induced syncope are characterised by a progressive decrement of parasympathetic activity, which does not occur in patients with a negative response to nitroglycerine. If confirmed on a wider population, HRV analysis could replace nitroglycerine administration and shorten the duration of the tilt test