Publications by authors named "Maria Fatima das Gracas Fernandes da Silva"

Greening, or Huanglongbing (HLB), poses a severe threat to global citrus cultivation, affecting various citrus species and compromising fruit production. Primarily transmitted by psyllids during phloem feeding, the bacterium Liberibacter induces detrimental symptoms, including leaf yellowing and reduced fruit quality. Given the limitations of conventional control strategies, the search for innovative approaches, such as resistant genotypes and early diagnostic methods, becomes essential for the sustainability of citrus cultivation.

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The aim of the study was to evaluate the effects of the seeds, exocarp and aril extracts from A. Juss. (Meliaceae) against and present the phytochemical study carried out with the aril extract of .

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Citrus canker, caused by the bacterium subsp. (), is a disease that causes serious problems to the global citrus industry. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry (MS) has been used in human medicine to diagnose various diseases caused by both fungi and bacteria.

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Soybean crop is regulated by abiotic and biotic stresses with great potential in reducing grain yield and quality. The selection of resistant cultivars is a promising approach for mitigating these damages. We evaluated the chemical profile of leaves from different cultivars in order to explore their defense mechanisms against caterpillars.

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Glyphosate excessive use is reported in Brazilian citrus orchards, whereas there is speculation about its consequences and the published studies are contradictory and inconclusive. This study aimed to describe the possible harmful effects by simulating glyphosate drift directly to the leaves of ∼4-yr-old citrus plants. As major results, glyphosate doses >360 g ae ha increased the shikimate accumulation in leaves (up to 2.

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Citrus black spot (CBS) is a disease caused by the fungus that affects citrus plants, causing fruit blemish and premature drop that result in severe economic losses in commercial citrus orchards. However, CBS symptoms and effects may vary depending on the citrus species: (lemon) is susceptible and highly affected by the disease, while no CBS-related damage has ever been observed for (Tahiti lime), implying that it must be resistant to the disease. The difference in the response to this disease provided the opportunity to gain insight into the metabolites responsible for the resistance by comparison of the metabolomic profiles of these two citrus species.

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The fungus is widely used for pest control; however, biostability and dispersion for broth pulverization are limiting factors for its application in the field. In this context, formulation techniques such as microencapsulation are viable alternatives. The aim of this work is to optimize formulations by spray dryer and evaluate its stability and biological activity against compared to ionic gelatinization formulations.

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Although many copper-based antimicrobial compounds have been developed to control pathogenic bacteria and fungi in plants and applied for crop protection, there is evidence that several plant pathogens have developed resistance to copper-based antimicrobial compounds, including some Xanthomonas species. Xylella is a bacterial genus belonging to the Xanthomonas family; and X. fastidiosa, which is responsible for citrus variegated chlorosis (CVC) in sweet orange, may develop resistance to one or more copper-based antimicrobials.

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In this work, we describe the insecticidal activity against of flavanone derivatives (naringin, naringenin and hesperidin) complexed to copper (II). For the assays, the compounds were incorporated into an artificial diet and offered to during its larval period. The duration of larval and pupal phases, the weight of pupae and the percentage of dead insects at the end of the larval phase were evaluated.

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Fruit processing waste, such as kernels (endocarp + seed) of avocado [Persea americana Mill. (Lauraceae)], could be used as raw material in the preparation of botanical insecticides. In light of this potential, this study assessed the insecticidal action of extracts and fractions from kernels of two avocado cultivars (Breda and Margarida) on Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype B, an important pest species in tropical conditions.

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Essential oils are volatile compounds commonly used by several industries, easily degradable, which restrains their applications. Therefore, we developed and validated a methodology for producing microcapsules loaded with orange essential oil, using a spray-drying process. The experimental design results showed that the combination between a low flow transfer rate (0.

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Article Synopsis
  • Tahiti lemon juice (TLJ) is being explored as a natural alternative to anti-inflammatory drugs for treating menstrual issues like dysmenorrhea by influencing prostaglandin levels.
  • The study analyzed TLJ's effects on specific pro-inflammatory cytokines and prostaglandins (PGF2α and PGE2) by using advanced analytical techniques and in vitro muscle contractions.
  • Results indicated that TLJ increases myoblast contractions and PGF2α levels during menstruation while reducing TNF-α levels, suggesting it may help regulate menstrual events through a PGF2α-mediated response.
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Papain-like cysteine proteases (PLCPs) in plants are essential to prevent phytopathogen invasion. In order to search for cysteine protease inhibitors and to investigate compounds that could be associated to pineapple Fusarium disease, a chemistry investigation was performed on Fusarium proliferatum isolated from Ananas comosus (pineapple) and cultivated in Czapek medium. From F.

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Rationale: Xylella fastidiosa causes citrus variegated chlorosis (CVC) in sweet orange trees. A diagnostic method for detecting CVC before the symptoms appear, which would inform citrus producers in advance about when the plant should be removed from the orchard, is essential for reducing pesticide application costs.

Methods: Chemometrics was applied to high-performance liquid chromatography diode array detector (HPLC-DAD) data to evaluate the similarities and differences between the chromatographic profiles.

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In natural product studies, the purification of metabolites is an important challenge. To accelerate this step, alternatives such as integrated analytical tools should be employed. Based on this, the chemical study of (Rutaceae) was performed using two rapid dereplication strategies: (Bruker Daltonics, Bremen, Germany) MS data analysis combined with MS/MS data obtained from the GNPS platform.

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Two highly oxygenated nortriterpenes, picraviane A and B, were isolated from the ethanolic extract of Picramnia glazioviana Engl. The structures were determined by analysis of HRMS and 2D NMR spectroscopic data. Single-crystal X-ray diffraction data was also obtained for picraviane B.

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A high performance liquid chromatography (HPLC) method was developed for the simultaneous isolation, on a semi-preparative scale, of chavibetol and methyleugenol from the crude essential oil of leaves. The purity of the isolated compounds and their quantifications were developed using GC/FID. Chavibetol was isolated with high purity (98.

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Eight alkaloids (⁻) were isolated from , and their herbicide activities were evaluated through in vitro, semivivo, and in vivo assays. The most relevant results were observed for Compounds and ⁻ at 150 μM, which decreased dry biomass by 20% and 23%, respectively. These are significant results since they presented similar values with the positive control, commercial herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU).

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Sclerotinia sclerotiorum is responsible for the white mold of soybeans, and the difficulty to control the disease in Brazil is causing million-dollar damages. Stachybotrys levispora has shown activity against S. sclerotiorum.

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The treatment of diseases using enzymes as targets has called for the development of new and reliable methods for screening. The protease cathepsin D is one such target involved in several diseases such as tumors, degenerative processes, and vital processes of parasites causing schistosomiasis. Herein, we describe the preparation of a fused silica capillary, cathepsin D (CatD)-immobilized enzyme reactor (IMER) using in a multidimensional High Performance Liquid Chromatography-based method (2D-HPLC) and zonal affinity chromatography as an alternative in the search for new ligands.

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Water scarcity can elicit drastic changes in plant metabolic and hormonal regulation, which may be of fundamental importance to stress tolerance. The study of plant the metabolic alterations in response to water deficit, especially the effects of the rootstocks level, is important to elucidate the mechanisms associated to drought tolerance. To verify the influence of rootstock and grafting on the tolerance to drought in citrus plants, we analyzed the growth, phytohormone levels and flavonoid profiles in grafted and ungrafted citrus plants subjected to different soil water regimes on plant status (well-watered, moderate drought and severe drought and rehydrated) under field conditions.

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Diketopiperazines can be generated by non-enzymatic cyclization of linear dipeptides at extreme temperature or pH, and the complex medium used to culture bacteria and fungi including phytone peptone and trypticase peptone, can also produce cyclic peptides by heat sterilization. As a result, it is not always clear if many diketopiperazines reported in the literature are artifacts formed by the different complex media used in microorganism growth. An ideal method for analysis of these compounds should identify whether they are either synthesized de novo from the products of primary metabolism and deliver true diketopiperazines.

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Antidesmone, isolated from Waltheria brachypetala Turcz., owns special structural features as two α,β-unsaturated carbonyl groups and a side alkyl chain that can compete with the quinones involved in the pool of plastoquinones at photosystem II (PSII). In this work, we showed that the alkaloid is an inhibitor of Hill reaction and its target was located at the acceptor side of PSII.

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