Protein glycation:a wolf in sweet sheep’s clothing behind neurodegeneration

At the beginning of the 16th century,Paracelsus coined the maxim:“the dose makes the poison”.This principle can be applied to all living organisms,including organs and cells.The brain and its glial and neuronal cells are no exception.Even small compounds that are essential for the life of brain cells can become truly toxic when overdosed.

Computational Chemistry and Molecular Modeling Techniques for the Study of Micropeptin EI-964: Insights into Its Chemical Reactivity and Potential Pharmaceutical Properties

Micropeptin EI-964 is a cyclic peptide compound isolated from a marine cyanobacterium with potent inhibitory activity against serine proteases, particularly chymotrypsin and trypsin. It has shown promising activity against various cancer cell lines, making it a candidate for drug development. The unique structure and activity of Micropeptin EI-964 make it a promising lead compound for the development of novel serine protease inhibitors and anti-cancer drugs. Computational Chemistry and Molecular Modeling techniques can provide valuable insights into the chemical reactivity and pharmaceutical properties of Micropeptin EI-964, guiding the design and development of new compounds with enhanced bioactivity and improved drug-like properties.

Conceptual Density Functional Theory Study of the Chemical Reactivity Properties and Bioactivity Scores of the Leu-Enkephalin Opioid Peptide Neurotransmitter

The SMD solvation model (Solvation Model based on the Density) and eight density functionals, CAM-B3LYP, LC-ωPBE, M11, MN12SX, N12SX, ωB97, ωB97X, and ωB97XD, were assessed in link with the Def2TZVP basis set for the calculation of the structure of the Leu-Enkephalin Opioid Peptide Neurotransmitter as well as their molecular properties. Through the Conceptual Density Functional Theory (CDFT), the entire chemical descriptors for the system were calculated. The active regions of the molecules necessary for electrophilic, nucleophilic and radical attacks were chosen through linking them with the corresponding Fukui functions. Furthermore, the prediction of the pKa value for the peptide is done with great accuracy as well as the ability of the studied molecule in acting as an efficient inhibitor of the formation of Advanced Glycation Endproducts (AGEs), which comprises of a useful knowledge for the development of drugs for preventing Alzheimer, Diabetes and Parkinson diseases. Lastly, the bioactivity scores for the studied peptides are predicted via various methodologies.

Chemical Reactivity Properties, Drug-Likeness Features and Bioactivity Scores of the Cholecystokinin Peptide Hormone

Five density functionals, CAM-B3LYP, LC-ωPBE, MN12SX, N12SX and ωB97XD, in connection with the Def2TZVP basis set were assessed together with the SMD solvation model for the calculation of the molecular and chemical reactivity properties of the Cholecystokinin peptide hormone (CCK-8) in the presence of water. All the chemical reactivity descriptors for the systems were calculated via Conceptual Density Functional Theory (CDFT). The potential bioavailability and druggability as well as the bioactivity scoresfor CCK-8 were predicted through different methodologies already reported in the literature which have been previously validated during the study of different peptidic systems. The conclusion was that the CCK-8 peptide will be moderately bioactive regarding all the interactions.

Comparative Study of the Chemical Reactivity of Helical Peptide Models for Protein Glycation

Non-enzymatic glycation of proteins has been implicated as an important cause of the complications associated with diabetes and Alzheimer disease. It is well known that glycation involves the reactivity of, primarily, the ε-amino group of the lysines present in the protein. The immediate chemical environment of an amino group modulates the glycation reaction. In this work, several model helical peptides for protein glycation has been studied by resorting to QM:MM calculations through the ONIOM methodology. Some Conceptual DFT descriptors have been calculated that allowed the comparison of the chemical reactivity between the different model peptides in terms of the position of the Lys group and other spatially proximate amino acid residues.

Chemical Reactivity Theory (CRT) Study of the Melanoidin M8: Local Conceptual Density Functional Theory Descriptors

This study evaluated a fixed long-range corrected range-separated hybrid (RSH) density functional associated with the Def2TZVP basis set alongside the Solvation Model based on Density (SMD) for the computation of the structure, molecular properties and chemical reactivity of the M8 intermediate melanoidin pigment. The preference of the active sites pertinent to radical, nucleophilic and electrophilic attacks is made through linking them with the electrophilic and nucleophilic Parr functions, Fukui function indices, and condensed Dual Descriptor. This study showed that the MN12SX density functional is the most suitable one for predicting the chemical reactivity of this system.

Computational Study of the Chemical Reactivity and Bioactivity Rates of Marine Peptides Hemiasterlin and Its A and B Derivatives Used in the Cancer Treatment through Conceptual Density Functional Theory

This study involved the assessment of the MNI2SX/Def2TZVP/H2O model chemistry to enhance the understanding of the structural composition of the marine peptide Hemiasterlin and its derivatives A and B used in cancer treatment. The Conceptual Density Functional theory was used in the calculation of molecular properties of the system chemical descriptors during the study. Integration of the active molecular regions into their respective Fukui functions was used in the selection of electrophilic and nucleophilic attacks. Additionally, the proposed correlation between global hardness and the pKa was used as the basis of deriving accurate predictions for the pKa values while a homology technique was used in the prediction of bioactivity and bioavailability scores of the peptides under investigation.

Towards defining soil quality of Mediterranean calcareous agricultural soils:Reference values and potential core indicator set

To avoid soil degradation,adapt to climate change and comply with the Sustainable Development goals 2030(UN General Assembly),establishing the quality/fertility of the agricultural soils of the Mediterranean region and evaluate how these evolve with time is mandatory.This enables adequate management practices to be implemented.The Mediterranean calcareous region has received little attention in this sense,in spite its soil particularities.So,24 different representative calcareous agricultural soils of the Mediterranean region,including the main management strategies of agricultural soils(rainfed and irrigated),were sampled from the island of Mallorca;and their physical,chemical and biological properties determined.The values obtained for most of the soil characteristics allowed to establish an initial approach to the reference values for the type of calcareous agricultural soils considered,and to clearly distinguish the effect of rainfed or irrigation management practices on soils properties and dynamics.Some enzyme activities were not stimulated by the irrigation conditions assayed or they were only in dry conditions,suggesting optimum enzyme activities could be obtained when alternating dry and humid soil conditions.Soil organic carbon,calcium carbonate and active lime revealed of significant importance in the collection of soils.Finally,the results obtained clearly indicate the heterogeneity of the region and its implications on the different soil characteristics.Therefore,this study could serve as a starting point to adequately establish the quality(fertility)for Mediterranean calcareous agricultural soils and their reference values by conducting further research in this region and including more type of soils.

外源ABA和水分胁迫对不同基因型三叶草生长的影响(英文)

在室内研究了不同浓度外源ABA处理和不同水分胁迫对 6种不同基因型的三叶草 (TrifoliumsubterraneumL .)生长的影响。当三叶草的第四片叶完全展开时 ,向营养液中施加不同浓度的ABA时对盆栽土壤进行控水。在处理的 1,4 ,7和 11d ,测定植株鲜重、叶片数、最长根长 ,以表示三叶草的生长状况。各参试品种以上三项生长指标均受外源ABA和水分胁迫的影响而呈现下降的趋势。同时 ,叶片水势值随ABA浓度的增加和水分胁迫强度的增加而明显降低。在 10 -4mol/LABA处理 11d后 ,参试品种平均生长量的减少与水分胁迫 15d后其生长量的减少的结论一致。在不同浓度ABA处理下 ,不同基因型三叶草平均叶片数 ,完全展开叶面积和每株干物质重约降低了5 0 % ,而其根冠比却增加了 80 %。不同基因型三叶草生长参数间的变化及排序结果与盆栽相同品种获得的实验结果非常相似。品种Clare、Nuba和SeatonPark在对照和处理下均表现最好。由于三叶草对一定浓度范围的外源ABA的反应与其在盆栽水分胁迫下的反应结果十分相似 ,因此 ,利用外源ABA处理的方法来研究不同基因型三叶草的耐旱性将可能是一种行之有效的方法。

The Janus face of N-terminal lysines in α-synuclein

Parkinson’s disease(PD)is the second most prevalent progressive neurodegenerative disorder after Alzheimer’s disease.PD usually starts with a tremor in the extremities(usually in the hands)and gradually evolves with other symptoms such as bradykinesia,muscle stiffness,impaired posture,loss of automatic movements or speech changes.These symptoms worsen as the condition progresses and eventually lead to death.

DNA metabarcoding the diet of Podarcis lizards endemic to the Balearic Islands

Dietary studies are essential to unravel the functioning of ecosystems and ultimately to understand biodiversity.This task,which at first may seem simple,becomes especially complex in those cases of omnivorous species with highly variable diets.In this regard,the emergence of next-generation DNA sequencing methodologies represents a powerful tool to address the problem.Here we implement a high-throughput metabarcoding strategy based on the analysis of four molecular markers aimed at sequencing both mitochondrial(animal prey)and chloroplast(diet plants)genome fragments from fecal samples of two lizard species endemic to the Balearic Archipelago(Podarcis lilfordi and P.pityusensis)obtained through non-invasive methods.The results allowed for the characterization of their diets with a high degree of taxonomic detail and have contributed a large number of new trophic records.The reported diets are based mainly on the consumption of arthropods,mollusks and plants from a diversity of taxonomic orders,as well as carrion and marine subsidies.Our analyses also reveal inter-and intra-specific differences both in terms of seasonality and geographical distribution of the sampled lizard populations.These molecular findings provide new insights into the trophic interactions of these threatened endemic lizards in their unique and isolated ecosystems.

Size effect on the microstructure, phase transformation behavior, and mechanical properties of NiTi shape memory alloys fabricated by laser powder bed fusion

In this work,NiTi samples with different thicknesses(0.15-1.00 mm)were fabricated by laser powder bed fusion(LPBF)under variable scanning speeds(500-1200 mm s^(-1)).The densification behavior,phase transformation behavior,and mechanical properties of the sample with different thicknesses are studied.The results indicate a strong size effect in the LPBF-fabricated NiTi alloy.The decrease of the sample thickness results in(i)the increase of porosity,(ii)the decrease of the number of adhered NiTi powder particles at the surface,(iii)the monotonous decrease of the martensitic transformation temperatures(MTTs),and(iv)the decrease of the shape recovery temperature.The influence of sample thickness on the melt-pool behavior,and thus the microstructure and performance of NiTi alloys are discussed.It is suggested that the melt-pool is deeper and narrower in the thin samples than in the thick samples.We conclude that,apart from the LPBF process conditions,the sample dimensions have also to be considered to fabricate NiTi structures with predictable properties.

Altitudinal variation in the reproductive performance of the Mediterranean shrub Rhamnus lycioides L.

Aims Rhamnus lycioides L.subsp.Oleoides(Rhamnaceae)is a perennial shrub native to the Mediterranean Basin distributed along an altitudinal gradient,from sea level up to 1000 m a.s.l.The specific goals of our study were(i)to compare plant morphology between two contrasting populations,(ii)to determine the reproductive system of R.lycioides,quantifying the relative importance of insects and wind as pollen vectors,(iii)to test if pollen limitation differs between populations,(iv)to study the main factors influencing fruit set and(v)to compare plant reproductive performance(mass allocation to flowers,fruits and seeds)between the two habitats.Methods In the present study,we examined plant morphology and the reproductive performance of R.lycioides L.in contrasting environments in two populations located at the extremes of its altitudinal range in the island of Mallorca(Balearic Islands,Western Mediterranean Basin)along a 3-year period.Plant morphology,the relative importance of insects and wind as pollen vectors,the pollen limitation to seed production and the plant reproductive performance(mass allocation to flowers,fruits and seeds)were determined.Important Findings Rhamnus lycioides individuals showed a higher plant surface/plant height ratio at the mountain than at the coast.This species appeared to be ambophilous despite its inconspicuous flowers,although the relative importance of wind as a pollination vector was higher at the mountain than at the coastal site.Fruit set was much higher at the mountain,where pollen appeared to be a limiting factor.By contrast,fruit set was not limited by pollen availability at the coastal population,where resource(water and nutrients)limitation seemed to be more determining.Flower size was greater at the coast,in contrast to fresh fruit weight that was higher at the mountain.Despite the relatively few differences between sites in precipitation patterns along the study period,water availability appeared to be the key factor explaining not only fruit set but also the reproductive performance of this species in the study populations.

Subpicosecond pulses in a self-starting mode-locked semiconductor-based figure-of-eight fiber laser

We have experimentally studied the mode-locking dynamics of a polarization-maintaining figure-of-eight laser which has a semiconductor optical amplifier as gain medium. Self-starting mode-locking at the fundamental repetition rate of 18 MHz is obtained at the lasing threshold, and further increasing the bias current leads to the progressive emission of additional optical pulses in each round trip and eventually to mode-locked emission at increasingly high harmonics of the fundamental repetition rate, up to 2.45 GHz. The intensity autocorrelation of the amplified mode-locked pulses has a full width at half-maximum duration of 382 fs, which corresponds to a pulse duration of 247 fs.

Nestling sex ratio is unaffected by individual and population traits in the griffon vulture

Variation in offspring sex ratios is a central topic in animal demography and population dynamics.Most studies have focused on bird species with marked sexual dimorphism and multiple-nestling broods,where the offspring sex ratio is often biased due to different individual or environmental variables.However,biases in offspring sex ratios have been far less investigated in monomorphic and single-egg laying species,and few studies have evaluated long-term and large-scale variations in the sex ratio of nestling vultures.Here,we explore individual and environmental factors potentially affecting the secondary sex ratio of the monomorphic griffon vulture Gyps fulvus.We used information collected at three breeding nuclei from central Spain over a 30-year period(1990–2020)to analyse the effects of nestling age,parental age,breeding phenology,conspecific density,population reproductive parameters,and spatial and temporal variability on nestling sex.Sex ratio did not differ from parity either at the population or the nuclei level.No significant between-year differences were detected,even under highly changing conditions of food availability associated with the mad-cow crisis.We found that tree nesting breeders tend to have more sons than daughters,but as this nesting behavior is rare and we consequently have a small sample size,this issue would require additional examination.Whereas further research is needed to assess the potential effect of breeder identity on nestling sex ratio,this study contributes to understanding the basic ecology and population dynamics of Griffon Vultures,a long-lived species with deferred maturity and low fecundity,whose minor deviations in the offspring sex ratio might imply major changes at the population level.

Robust general N User authentication scheme in a centralized quantum communication network via generalized G HZ states

Quantum communication provides an enormous advantage over its classical counterpart： security of communications based on the very principles of quantum mechanics. Researchers have proposed several approaches for user identity authentication via entanglement. Unfortunately, these protocols fail because an attacker can capture some of the particles in a transmitted sequence and send what is left to the receiver through a quantum channel. Subsequently, the attacker can restore some of the confidential messages, giving rise to the possibility of information leakage. Here we present a new robust General N user authentication protocol based on N-particle Greenberger-Horne-Zeilinger （GHZ） states, which makes eavesdropping detection more effective and secure, as compared to some current authentication protocols. The security analysis of our protocol for various kinds of attacks verifies that it is unconditionally secure, and that an attacker will not obtain any information about the transmitted key. Moreover, as the number of transferred key bits N becomes larger, while the number of users for transmitting the information is increased, the probability of effectively obtaining the transmitted authentication keys is reduced to zero.

Multipartite quantum correlations among atoms in QED cavities

We study the nonlocality dynamics for two models of atoms in cavity quantum electrodynamics （QED）; the first model contains atoms in a single cavity undergoing nearest-neighbor interactions with no initial correlation, and tile second contains atoms confined in n different and noninteracting cavities, all of which were initially prepared in a maximally correlated state of n qubits corresponding to the atomic degrees of freedom. The nonlocality evolution of the states in the second model shows that the corresponding maximal violation of a multipartite Bell inequality exhibits revivals at precise times, defining, nonlocality sudden deaths and nonlocality sudden rebirths, in analogy with entanglement. These quantum correlations are provided analytically for the second model to make the study more thorough. Differences in the first model regarding whether the array of atoms inside the cavity is arranged in a periodic or open fashion are crucial to the generation or redistribution of quantum correlations. This contribution paves the way to using the nonlocality multipartite correlation measure for describing the collective complex behavior displayed by slightly interacting cavity QED arrays.

Central nucleus-nucleus collisions at relativistic energies with a new method based on Random Matrix Theory

Using the method based on Random Matrix Theory （RMT）, the results for the nearest-neighbor distributions obtained from the experimental data on ^12C-C collisions at 4.2 AGeV/c have been discussed and compared with the simulated data on ^12C-C collisions at 4.2 AGeV/c produced with the aid of the Dubna Cascade Model. The results show that the correlation of secondary particles decreases with an increasing number of charged particles Nch. These observed changes in the nearest-neighbor distributions of charged particles could be associated with the centrality variation of the collisions.