Federal University of Recôncavo da Bahia

This study presents a theoretical investigation of bidentate chelators for Pb2⁺ removal from aqueous systems using molecular dynamics simulations. Specifically, β-diketone- and dithiooxamide-based ligands, including a nanostructured derivative (LIG2), were evaluated to assess their coordination behavior, stability, and binding affinity toward lead ions. Simulations were conducted for 100 ns to ensure adequate conformational sampling, and key thermodynamic and structural parameters were analyzed, including potential energy, system density, and coordination stability. The results indicate that all ligands exhibit significant interaction with Pb2⁺ ions; however, differences in coordination persistence and structural stability were observed. The dithiooxamide-based systems, particularly the nanostructured ligand, demonstrated enhanced sequestration capacity, attributed to multiple active sites and a favorable coordination geometry. Despite relatively high RMSD values, the complexes remained stable throughout the simulation, with persistent metal–ligand interactions supporting effective chelation. Overall, this work establishes a predictive computational framework for screening chelating agents and highlights dithiooxamide-based ligands as promising candidates for Pb2⁺ removal. These findings provide a rational basis for future experimental validation and the development of efficient materials for wastewater remediation under realistic conditions.

Sorghum is a resilient crop of great agricultural importance, notable for its high efficiency in water and energy use. However, factors such as low soil nutrient availability and abiotic stresses can limit its productive potential. In this context, plant growth-promoting bacteria (PGPB) have proven to be sustainable alternatives as they can stimulate crop growth through biological nitrogen fixation (BNF) and tolerance to adverse stresses. This study aimed to conduct a bibliometric analysis with a narrative synthesis of scientific production on the use of PGPB in sorghum cultivation between 2014 and 2024. To this end, a search for scientific articles was conducted in the Scopus and Web of Science databases. The bibliographic data were refined and analyzed in the R software using the Bibliometrix package. It was possible to identify the main authors, institutions, journals, keywords, and scientific collaboration networks. An increase was observed in global scientific production, with Brazil and the United States of America standing out as leaders in publications. The research mainly addressed the effects of PGPB on sorghum growth, BNF, and mitigation of abiotic stresses, such as drought and heavy metal contamination. The use of PGPB was also related to phytoremediation, standing out as a strategy for environmental recovery and increased agricultural productivity. These results contribute to understanding trends and advances in the application of PGPB in sorghum cultivation, as well as providing subsidies for future research.

We report the discovery and delimitation of a new Manihot species, here named Manihot capsularis, from Serra de Grão Mogol, Minas Gerais, Brazil. Integrating morphological and molecular evidence, we distinguish this taxon from its sister species, M. caerulescens. Morphologically, M. capsularis is characterized by pubescent vegetative and reproductive structures, capsular fruits, seeds with a well-developed caruncle, and darker green leaves, whereas M. caerulescens typically has glabrous, lighter green leaves, baccate fruits, and seeds that are ecarunculate or have an inconspicuous caruncle. Phylogenetic analyses of three nuclear gene regions (ch_metE, g3pdh, and nia-i3) recovered two well-supported clades corresponding to the two species. A ch_metE haplotype network corroborated these lineages, with no haplotype sharing observed between them. Microsatellite data further supported species distinctiveness and population structure: Bayesian clustering identified three genetic groups, with all M. caerulescens specimens forming a single cluster, whereas M. capsularis specimens split into two distinct clusters with limited admixture. Genetic diversity metrics indicated private alleles in all M. capsularis populations and high observed heterozygosity. The new species is endemic to Campos rupestres on sandy soils and can be recognized in the field and in herbaria. Given its restricted distribution (extent of occurrence < 100 km2) and habitat specificity, M. capsularis is provisionally assessed as Critically Endangered. This study highlights the value of combining molecular and morphological data for robust species delimitation in taxonomically complex groups and underscores the need for conservation attention to narrowly endemic taxa within Manihot.

This work aims to review the monospecific Manihot anomala complex through an integrative approach that involves leaf morphometry, descriptive taxonomy, and ecological analysis. Four subspecies, as well as M. warmingii, are here synonymized under M. anomala as result of overlapping diagnostic characters and geographic distribution. Two leaf morphotypes stood out in the complex, but these could not be recognized at the species or subspecies level, as their morphological differences can likely be attributed to hybridization and recent adaptation to contrasting environmental conditions. Among the three tested environmental variables, precipitation was the most relevant, with statistically significant values for six of 12 morphological characters. We also found that the reproductive characters traditionally used to delimit subspecies of M. anomala are unreliable and of limited taxonomic value for infraspecific delimitation, due to their high variability, developmental instability, and extensive overlap among taxa. Finally, a treatment for M. anomala is provided, containing descriptive analysis, taxonomic decisions, and occurrence update, in addition to six lectotypifications. The present work helps to resolve the status of M. anomala, while providing tools for future studies involving both Manihot and other plant groups known for their high foliar plasticity.

The objective of this study was to isolate and select bacteria from soils with previous cassava wastewater deposition, aiming to identify strains capable of promoting vegetative growth of Vigna unguiculata L. Walp. Eight soil samples were collected near cassava flour processing facilities in Vitória da Conquista – Bahia and cultured on Burks and FAM media. Fifty-five bacterial isolates were obtained and evaluated for morphological characteristics, population density, calcium phosphate solubilization, sodium chloride tolerance, and ability to promote cowpea growth. Bacterial densities ranged from 2.31 × 10¹ to 2.15 × 10⁶ cells g⁻¹ soil in Burks medium and from 2.31 × 10¹ to 1.49 × 10⁵ cells g⁻¹ soil in FAM medium. Among the 55 isolates obtained, four were able to nodulate cowpea, and 27 tolerated NaCl concentrations up to 30 g L⁻¹. High bacterial densities were observed in both media, with most isolates showing rapid growth and low to moderate phosphate solubilization. Isolates tolerant to up to 30 g L⁻¹ NaCl were detected. Strains from the genera Bacillus and Paraburkholderia both widely reported as plant growth-promoting rhizobacteria (PGPR) were identified. Some non-nodulating isolates enhanced root length and dry weight, while nodulating strains UFRB BA72C2-1, UFRB FA34C2-2, UFRB FA51B1, and UFLA 03-164T were effective in nodulation and vegetative growth promotion.