Secondary Metabolic Profile as a Tool for Distinction and Characterization of Cultivars of Black Pepper (Piper nigrum L.) Cultivated in Pará State,Brazil

This study evaluated the chemical compositions of the leaves and fruits of eight black pepper cultivars cultivated in Pará State (Amazon, Brazil). Hydrodistillation and gas chromatography–mass spectrometry were employed to extract and analyze the volatile compounds, respectively. Sesquiterpene hydrocarbons were predominant (58.5–90.9%) in the cultivars “Cingapura”, “Equador”, “Guajarina”, “Iaçará”, and “Kottanadan”, and “Bragantina”, “Clonada”, and “Uthirankota” displayed oxygenated sesquiterpenoids (50.6–75.0%). The multivariate statistical analysis applied using volatile composition grouped the samples into four groups: γ-Elemene, curzerene, and δ-elemene (“Equador”/“Guajarina”, I); δ-elemene (“Iaçará”/“Kottanadan”/“Cingapura”, II); elemol (“Clonada”/“Uthirankota”, III) and α-muurolol, bicyclogermacrene, and cubebol (“Bragantina”, IV). The major compounds in all fruit samples were monoterpene hydrocarbons such as α-pinene, β-pinene, and limonene. Among the cultivar leaves, phenolics content (44.75–140.53 mg GAE·g⁻¹ FW), the enzymatic activity of phenylalanine-ammonia lyase (20.19–57.22 µU·mL⁻¹), and carotenoids (0.21–2.31 µg·mL⁻¹) displayed significant variations. Due to black pepper’s susceptibility to Fusarium infection, a molecular docking analysis was carried out on Fusarium protein targets using each cultivar’s volatile components. F. oxysporum endoglucanase was identified as the preferential protein target of the compounds. These results can be used to identify chemical markers related to the susceptibility degree of black pepper cultivars to plant diseases prevalent in Pará State.     

Biflavonoid-Induced Disruption of Hydrogen Bonds Leads to Amyloid-β Disaggregation

Deposition of amyloid β (Aβ) fibrils in the brain is a key pathologic hallmark of Alzheimer’s disease. A class of polyphenolic biflavonoids is known to have anti-amyloidogenic effects by inhibiting aggregation of Aβ and promoting disaggregation of Aβ fibrils. In the present study, we further sought to investigate the structural basis of the Aβ disaggregating activity of biflavonoids and their interactions at the atomic level. A thioflavin T (ThT) fluorescence assay revealed that amentoflavone-type biflavonoids promote disaggregation of Aβ fibrils with varying potency due to specific structural differences. The computational analysis herein provides the first atomistic details for the mechanism of Aβ disaggregation by biflavonoids. Molecular docking analysis showed that biflavonoids preferentially bind to the aromatic-rich, partially ordered N-termini of Aβ fibril via the π–π interactions. Moreover, docking scores correlate well with the ThT EC₅₀ values. Molecular dynamic simulations revealed that biflavonoids decrease the content of β-sheet in Aβ fibril in a structure-dependent manner. Hydrogen bond analysis further supported that the substitution of hydroxyl groups capable of hydrogen bond formation at two positions on the biflavonoid scaffold leads to significantly disaggregation of Aβ fibrils. Taken together, our data indicate that biflavonoids promote disaggregation of Aβ fibrils due to their ability to disrupt the fibril structure, suggesting biflavonoids as a lead class of compounds to develop a therapeutic agent for Alzheimer’s disease.     

锆基激光熔覆涂层组织结构及性能

在纯钛(TA2)基体上激光熔覆了Zr65Al75Ni10Cu17.5合金粉末，对涂层进行了XRD，SEM和TEM分析。研究发现，涂层由金属间化合物 少量的非晶组成。这种具有高比强度、高硬度和高抗氧化性的金属间化合物与非晶相的复合组织，具有较好的力学性能。在Zr65Al75Ni10Cu17.5合金粉末中添加w(B)2％和w(Si)2．75％，发现涂层中非晶含量增加，硬度升高。两种涂层的最高硬度分别达到HK909．6和HK1444．8。     

Selective preparation of light aromatic hydrocarbons from catalytic fast pyrolysis vapors of coal tar asphaltene over transition metal ion modified zeolites

The catalytic cracking of coal tar asphaltene (CTA) pyrolysis vapors was carried out over transition met-alion modified zeolites to promote the generation of light aromatic hydrocarbons (L-ArHs) in a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) micro-reactor system.The effects of ultra stable Y(USY),Co/USY and Mo/USY on the selectivity and yield of L-ArHs products and the extent of deoxygena-tion (Edeoxygenation),lightweight (Elightweight) from CTA pyrolysis volatiles were investigated.Results showed that the yields of L-ArHs are mainly controlled by the acid sites and specific surface area of the catalysts,while the deoxygenation effect is determined by theirs pore size.The Elightweight of CTA pyrolysis volatiles over USY is 9.65％,while the Edeoxygenation of CTA pyrolysis volatiles over Mo/USY reaches 20.85％.Additionally,the modified zeolites (Mo/USY and Co/USY) exhibit better performance than USY on L-ArHs production,owing to the synergistic effect of metal ions (Mo,Co) and acid sites of USY.Compared with the non-catalytic fast pyrolysis of CTA,the total yield of L-ArHs obtained over USY (4032 mg·kg-1),Co/USY (4363 mg·kg-1) and Mo/USY (4953 mg·kg-1) were increased by 27.03％,38.19％ and 54.78％,respectively.Furthermore,the possible catalytic conversion mechanism of transition metal ion (Co and Mo) modified zeolites was proposed based on the distribution of products and the characterizations of catalysts.     

ZrO2制备方法研究进展

以ZrO₂为活性组分或载体的催化剂,在酚类定向催化转化中具有较高的研究价值。总结了ZrO₂的各种制备方法,包括溶胶-凝胶法、共沉淀法、水热法、表面活性剂辅助法、静电纺丝法、热解法、多元醇还原法、反相微乳法和超临界合成法等。阐述了各种方法的反应原理,详细比较了不同制备方法的优劣,并具体分析了制备方法对催化剂结构及性能的影响。     

Structural Investigation and Molecular Modeling Studies of Strobilurin-Based Fungicides Active against the Rice Blast Pathogen Pyricularia oryzae

The increasing emergence of fungicide-resistant pathogens requires urgent solutions for crop disease management. Here, we describe a structural investigation of new fungicides obtained by combining strobilurin and succinate dehydrogenase inhibitor pharmacophores. We identified compounds endowed with very good activity against wild-type Pyricularia oryzae, combined in some cases with promising activity against strobilurin-resistant strains. The first three-dimensional model of P. oryzae cytochrome bc1 complex containing azoxystrobin as a ligand was developed. The model was validated with a set of commercially available strobilurins, and it well explains both the resistance mechanism to strobilurins mediated by the mutation G143A and the activity of metyltetraprole against strobilurin-resistant strains. The obtained results shed light on the key recognition determinants of strobilurin-like derivatives in the cytochrome bc1 active site and will guide the further rational design of new fungicides able to overcome resistance caused by G143A mutation in the rice blast pathogen.     

Engineering of Janus-Like Dendrimers with Peptides Derived from Glycoproteins of Herpes Simplex Virus Type 1: Toward a Versatile and Novel Antiviral Platform

Novel antiviral nanotherapeutics, which may inactivate the virus and block it from entering host cells, represent an important challenge to face viral global health emergencies around the world. Using a combination of bioorthogonal copper-catalyzed 1,3-dipolar alkyne/azide cycloaddition (CuAAC) and photoinitiated thiol–ene coupling, monofunctional and bifunctional peptidodendrimer conjugates were obtained. The conjugates are biocompatible and demonstrate no toxicity to cells at biologically relevant concentrations. Furthermore, the orthogonal addition of multiple copies of two different antiviral peptides on the surface of a single dendrimer allowed the resulting bioconjugates to inhibit Herpes simplex virus type 1 at both the early and the late stages of the infection process. The presented work builds on further improving this attractive design to obtain a new class of therapeutics.     

Gurum Seeds: A Potential Source of Edible Oil

Cucurbitaceae family seeds are mostly discarded as agro-industrial wastes. Gurum (Citrullus lanatus var. colocynthoide) is an underutilized wild cucurbit plant, closely related to desert watermelon, which is grown abundantly in some African countries. Gurum seeds can play a significant role in health and nutrition due to their high oil content. This review describes the nutritional composition of gurum seeds and their oil profile. Gurum seeds are a good source of oil (27–35.5%), fiber (26–31%), crude protein (15–18%), and carbohydrates (14–17%). Gurum seeds oil is extracted by supercritical CO₂ (SFE), screw press, and solvent extraction techniques. The gurum seeds oil is composed of unsaturated fatty acids with a high proportion of linoleic acid (C18:2) and oleic acid (C18:1). Gurum seeds oil contains various bioactive compounds, such as tocopherols, phytosterols, and polyphenols. It is reported that solvent extraction gives a higher yield than the screw press and SFE, but the SFE is preferred due to safety issues. More studies are required for producing better quality gurum seeds oil by using novel extraction techniques that can increase oil yield.