Glenda Quaresma Ramos

Surface architecture plays a fundamental role in governing the interaction between biological interfaces and their surrounding environment. In this study, we present a comprehensive multiscale surface metrology analysis of the adaxial and abaxial leaf interfaces of Couepia bracteosa a combination of optical microscopy, scanning electron microscopy, and three-dimensional confocal profilometry. Quantitative characterization was performed according to ISO 25178-2 areal surface texture parameters complemented by power spectral density (PSD) analysis, Hurst exponent estimation, fractal dimension (FD) evaluation, and Hough transform-based structural mapping. The results reveal two distinct surface regimes. The adaxial interface exhibits a comparatively smooth and spatially coherent topography, with low roughness amplitude ( S _q = 1.0 ± 0.2 µ m) and near-Gaussian height distribution. In contrast, the abaxial interface presents a highly heterogeneous and hierarchically structured surface, characterized by a significant increase in roughness ( S _q = 10 ± 1 µ m), broader height distributions, and reduced spatial persistence. PSD analysis demonstrated a decrease in the Hurst exponent (from 0.66 to 0.38) and a corresponding increase in the FD (from 2.34 to 2.62), indicating enhanced multiscale irregularity. Hough transform analysis further revealed an increased orientational dispersion on the abaxial surface. These findings demonstrate that dorsiventral leaf asymmetry corresponds to a transition between two distinct topographic regimes, governed by differences in amplitude, spatial organization, and hierarchical complexity. This study highlights the relevance of advanced surface metrology tools for the quantitative description of biological interfaces and provides a framework for linking multiscale surface architecture to functional interactions in natural systems.

Background/Objectives: In the Brazilian Amazon, which accounts for over 99% of national malaria cases, 34,260 cases were reported as of August 2025, predominantly caused by Plasmodium vivax, responsible for 86.69% of the infections. The increasing resistance of the parasite to conventional therapies highlights the urgent need for novel control strategies, with essential oils and plant-derived substances emerging as promising alternatives. Methods: In this context, we evaluated the anti-Plasmodium potential of Piper alatipetiolatum essential oil and its major constituent 6-ishwarone against P. vivax, including cytotoxicity in Vero and PBMCs, molecular docking on dihydrofolate reductase (DHFR) and lactate dehydrogenase (LDH), and in silico pharmacokinetic profiling. Results: Both the oil and 6-ishwarone inhibited P. vivax dose-dependently (2.1 ± 1 to 100%), with IC₅₀ values of 9.25 µg/mL and 3.93 µg/mL, respectively. Importantly, no cytotoxic effects were observed at 24 h, with cell viability ranging from 94.7% to 98.3%, highlighting the selectivity of these compounds towards the parasite over mammalian cells. Docking studies indicated selective binding of 6-ishwarone to DHFR (−7.7 kcal/mol; Ki = 2.27 µM) with key interactions (Trp816, Lys820, Tyr819, Asn823, Thr865), whereas binding to LDH was weaker (−6.2 kcal/mol; Ki = 28.10 µM), suggesting DHFR as the primary molecular target. In silico ADMET predictions and experimental data indicated favorable drug-like properties: TPSA = 20.23 Ų, moderate lipophilicity (LogP = 3.37), soluble (ESOL Log S = −3.58; Ali Log S = −3.89; Silicos-IT Log S = −2.84), high gastrointestinal absorption, BBB permeability (0.985), not a P-glycoprotein substrate (0.11), and low likelihood of CYP inhibition. Toxicity predictions showed non-mutagenic and non-hepatotoxic effects, low cardiotoxicity (hERG inhibition risk 0.08–0.32), low reproductive toxicity (0.03), moderate neurotoxicity (0.28), low acute toxicity (oral LD₅₀ = 2.061 mol/kg), and low chronic toxicity (LOAEL = 1.995 log mg/kg/day). Conclusions: Together, these findings demonstrate that essential oil and 6-ishwarone of P. alatipetiolatum are selective, bioavailable, and promising natural leads for antimalarial drug development.

Deciphering the nanoscale architecture of mosquito wings is crucial for understanding species-specific flight adaptations and vectorial behaviors. In this study, we present a comprehensive quantitative analysis of the wing surface morphology of Anopheles darlingi and Anopheles aquasalis. By integrating high-resolution microscopy with Minkowski functionals and multifractal formalism, we reveal pronounced interspecific and dorso-ventral asymmetries in mosquito wing surfaces at both micro- and nanoscales. Atomic force microscopic topographies revealed distinct differences in dorsal versus ventral surface roughness, with An. aquasalis displaying higher elevation variance and denser nanomorphological heterogeneity. Minkowski volume and boundary descriptors showed slower decay and broader distribution for An. aquasalis, especially on its dorsal side, indicative of complex topographic relief. Multifractal spectra, derived from the box-counting method across q = −10 to +10, exhibited larger width (Δα ≈ 1.073) and stronger left-symmetry (H ≈ −0.852) in An. aquasalis, compared to narrower and more symmetric spectra in An. darlingi (Δα ≈ 1.009; H ≈ −0.532). Generalized fractal dimensions (D0 ≈ 2.00; D2 range: 1.951–1.982) and singularity spectra asymmetry (Δf up to −1.732) further differentiated species and wing sides. These multiscale descriptors demonstrate that An. aquasalis, particularly its ventral surface, harbors higher degrees of nanomorphological complexity and textural irregularity.

This study presents a detailed analysis of the thermal degradation and kinetic behavior of two Amazonian wood species, Goupia glabra (cupiúba) and Manilkara huberi (maçaranduba), using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR-ATR), and direct infusion mass spectrometry (DIMS). Wood samples were subjected to controlled heating rates of 20, 40, and 60 °C/min from 25 to 800 °C under an argon atmosphere. TGA revealed moisture evaporation below 120 °C, with hemicellulose degradation occurring between 220 and 315 °C, cellulose decomposition between 315 and 400 °C, and lignin breakdown over a broader range from 180 to 900 °C. The highest rate of mass loss occurred at 363.99 °C for G. glabra and 360.27 °C for M. huberi at a heating rate of 20 °C/min, with shifts to higher temperatures at faster heating rates. Activation energies were calculated using Arrhenius and Kissinger models, yielding values between 53.46–61.45 kJ/mol for G. glabra and 58.18–62.77 kJ/mol for M. huberi, confirming their stable thermal profiles. DSC analysis identified a significant endothermic peak related to moisture evaporation below 100 °C, followed by two exothermic peaks. For G. glabra, the first exothermic peak appeared at 331.45 °C and the second at 466.08 °C, while for M. huberi, these occurred at 366.41 °C and 466.08 °C, indicating the decomposition of hemicellulose, cellulose, and lignin. Enthalpy values for G. glabra were 12,633.37 mJ and 18,652.66 mJ for the first and second peaks, respectively, while M. huberi showed lower enthalpies of 9648.04 mJ and 14,417.68 mJ, suggesting a higher energy release in G. glabra. FTIR-ATR analysis highlighted the presence of key functional groups in both species, with strong absorption bands in the 3330–3500 cm⁻¹ region corresponding to O-H stretching vibrations, indicative of hydroxyl groups in cellulose and hemicellulose. The 1500–1600 cm⁻¹ region, representing aromatic C=C vibrations, confirmed the presence of lignin. Quantitatively, these results suggest a high content of cellulose and lignin in both species. DIMS analysis further identified polyphenolic compounds and triterpenoids in M. huberi, with major ions at m/z 289 and 409, while G. glabra showed steroidal and polyphenolic compounds with a base peak at m/z 395. These findings indicate the significant presence of bioactive compounds, contributing to the wood’s resistance to microbial degradation. This comprehensive thermal and chemical characterization suggests that both species have potential industrial applications in environments requiring high thermal stability.

Plant leaf surfaces can contain interesting, reproducible spatial patterns that can be used for several industrial purposes. In this paper, the main goal was to analyze the surface microtexture of Amazon Anacardium occidentale L. using multifractal theory. AFM images were used to evaluate the multifractal spatial surface patterns of the adaxial and abaxial sides of the leaf. The 3D maps revealed that the abaxial side is dominated by stomach cells, while striated structures were observed on the adaxial side. The surface of the abaxial side is rougher than the adaxial side. The autocorrelation function calculations showed that the abaxial side has an isotropic surface compared to the adaxial side. Despite this, Minkowski functionals demonstrated that the morphological spatial patterns have robust statistical similarity. Both sides exhibit multifractal behavior, which was verified by the trend observed in the mass exponent and generalized dimension. However, the adaxial side exhibits stronger multifractality and increased vertical complexity compared to the abaxial side. Our findings show that the multifractal spatial patterns of the leaf surface depend on the rough dynamics of the topographic profile. The identification of the multifractal patterns of the structures present on the surface of plant leaves is useful for the fabrication of leaf-architecture-based materials.

Anais do Simpósio SBMM de Ciências da Vida (978-85-5722-486-5) - Acidocalcisome Of Plasmodium Vivax Sporozoites