Alex-alan Almeida - Academia.edu (original) (raw)

Papers by Alex-alan Almeida

PLOS ONE

Galactinol synthase (GolS) catalyzes the first and rate-limiting step in the synthesis of raffino... more Galactinol synthase (GolS) catalyzes the first and rate-limiting step in the synthesis of raffinose family of oligosaccharides (RFOs), which serve as storage and transport sugars, signal transducers, compatible solutes and antioxidants in higher plants. The present work aimed to assess the potential functions of citrus GolS in mechanisms of stress response and tolerance. By homology searches, eight GolS genes were found in the genomes of Citrus sinensis and C. clementina. Phylogenetic analysis showed that there is a GolS ortholog in C. clementina for each C. sinensis GolS, which have evolved differently from those of Arabidopsis thaliana. Transcriptional analysis indicated that most C. sinensis GolS (CsGolS) genes show a low-level tissue-specific and stress-inducible expression in response to drought and salt stress treatments, as well as to ‘Candidatus Liberibacter asiaticus’ infection. CsGolS6 overexpression resulted in improved tobacco tolerance to drought and salt stresses, cont...

Environmental science and pollution research international, Jan 17, 2017

Cadmium (Cd) is a metal known for its genotoxicity and cytotoxicity, much concerned for its poten... more Cadmium (Cd) is a metal known for its genotoxicity and cytotoxicity, much concerned for its potential environmental and human health impacts. This study evaluates the toxic effect of Cd in Calophyllum brasiliense plants. The plants were cultivated for 30 days in full nutrient solution in order to adapt, and for 15 days in nutrient solution without Cd or with 4, 8, 16, and 32 μmol Cd L(-1). Anatomical analysis of the leaf showed no significant effects of Cd on epidermal thickness in abaxial and adaxial sides, palisade, and spongy parenchyma. Contrastingly, changes were noticed in the ultrastructural level in the leaf mesophyll cells as rupture of the membrane of chloroplasts and disorganization of the thylakoid membranes, in starch grains and in mitochondria with rupture of the membrane and invagination of the nuclear membrane. Electron dense materials into cells of the cortex and vascular bundle were also observed. In the cells of the root system, the observed ultrastructural change...

Physiologia plantarum, 2012

In ecological setting, sodium (Na(+)) can be beneficial or toxic, depending on plant species and ... more In ecological setting, sodium (Na(+)) can be beneficial or toxic, depending on plant species and the Na(+) level in the soil. While its effects are more frequently studied at high saline levels, Na(+) has also been shown to be of potential benefit to some species at lower levels of supply, especially in C4 species. Here, clonal plants of the major tropical C3 crop Theobroma cacao (cacao) were grown in soil where potassium (K(+)) was partially replaced (at six levels, up to 50% replacement) by Na(+), at two concentrations (2.5 and 4.0 mmol(c) dm(-3)). At both concentrations, net photosynthesis per unit leaf area (A) increased more than twofold with increasing substitution of K(+) by Na(+). Concomitantly, instantaneous (A/E) and intrinsic (A/g(s)) water-use efficiency (WUE) more than doubled. Stomatal conductance (g(s)) and transpiration rate (E) exhibited a decline at 2.5 mmol dm(-3), but remained unchanged at 4 mmol dm(-3). Leaf nitrogen content was not impacted by Na(+) supplementa...

Ecotoxicology and Environmental Safety, 2015

Seeds from Theobroma cacao progenies derived from the self-pollination of 'Catongo' Â 'Catongo' a... more Seeds from Theobroma cacao progenies derived from the self-pollination of 'Catongo' Â 'Catongo' and the crossing between CCN-10 Â SCA-6 were immersed for 24 h in different Cd solutions (2; 4; 8; 16 and 32 mg L À 1) along with the control treatment (without Cd). Shortly after, the seeds were sown in plastic tubes containing organic substrate and were grown in a greenhouse for 60 days. The treatment with Cd was observed to cause morphological, biochemical, molecular and ultrastructural changes in both progenies of T. cacao. There has been deformation in chloroplasts, nuclear chromatin condensation, and reduction in thickness of the mesophyll. As for 'Catongo' Â 'Catongo', a decrease in thickness of the epidermis was noted on the abaxial face. There has been increased guaiacol peroxidase activity in the roots of CCN-10 Â SCA-6, as well as in the''Catongo' Â 'Catongo' leaves. In the presence of Cd, CCN-10 Â SCA-6 showed increased expression of the genes associated with the biosynthesis of phytochelatin (PCS-1) and class III peroxidases (PER-1) in leaves, and metallothionein (MT2b), in roots. In 'Catongo' Â 'Catongo', there has been an increase in the expression of genes associated with the biosynthesis of PER-1 and cytosolic superoxide dismutase dependent on copper and zinc (Cu-Zn SOD Cyt) in leaves and from MT2b and PCS-1 and roots. There was higher accumulation of Cd in the aerial parts of seedlings from both progenies, whereas the most pronounced accumulation was seen in''Catongo' Â 'Catongo'. The increase in Cd concentration has led to lower Zn and Fe levels in both progenies. Hence, one may conclude that the different survival strategies used by CCN-10 Â SCA-6 made such progeny more tolerant to Cd stress when compared to''Catongo' Â 'Catongo'.

HortScience, 2018

Passiflora are ornamental plants that are appreciated as part of outdoor decor, composing pergola... more Passiflora are ornamental plants that are appreciated as part of outdoor decor, composing pergolas and gardens, as well as in interior ornamentation where species tolerant to environments with less light availability are used. The objective of this study was to evaluate the influence of different levels of light and pot types on morphological and reproductive characteristics in Passiflora subrotunda and to support genetic breeding programs of ornamental passifloras. The conditions of 75% and 100% light favored vegetative morphological characteristics through the time (105 days). Floral characteristics also presented higher values along increasing light levels. All qualitative characters related to flower and plant coloration did not vary among genotypes. The species possesses diurnal anthesis and flowers throughout the year. Plants cultivated in concrete pots showed greater growth and flower production. Pollen grains (PGs) are large, with an isopolar form, a small polar area, and a ...

Crop Breeding and Applied Biotechnology, 2019

Journal of Experimental Agriculture International, 2019

Aims: This study evaluated carbon assimilation, water relations, intrinsic and instantaneous wate... more Aims: This study evaluated carbon assimilation, water relations, intrinsic and instantaneous water use efficiency, and water consumption of two cultivars of Ricinus communis L. cv. BRS 188 Paraguaçu and BRS Energia, subjected to regulated-deficit irrigation. Study Design: The experiment was arranged in a completely randomized scheme in a factorial arrangement of 5 x 2, with five replicates. Place and Duration of Study: The experiment was conducted in a greenhouse at the Universidade Estadual de Santa Cruz, Ilhéus, Brazil from December 2008 to February 2009. Methodology: The growing plants were subjected to different water conditions by predefined quantities of water, so as to maintain the substrate under the following matric potential (Ψm) during Original Research Article

Brazilian Journal of Plant Physiology

High concentrations of Cd, Pb, Cu and Cr can cause harmful effects to the environment. These high... more High concentrations of Cd, Pb, Cu and Cr can cause harmful effects to the environment. These highly toxic pollutants constitute a risk for aquatic and terrestrial life. They are associated with diverse bioavailable geochemical fractions, like the water-soluble fraction and the exchangeable fraction, and non-available fractions like those associated with the crystalline net of clays and silica minerals. Depending upon their chemical and physical properties we can distinguish different mechanisms of metal toxicity in plants, such as production of reactive oxygen species from auto-oxidation, blocking and/or displacement of essential functional groups or metallic ions of biomolecules, changes in the permeability of cellular membranes, reactions of sulphydryl groups with cations, affinity for reactions with phosphate groups and active groups of ADP or ATP, substitution of essential ions, induction of chromosomal anomalies and decrease of the cellular division rate. However, some plant sp...

PloS one, 2015

The phytocystatins regulate various physiological processes in plants, including responses to bio... more The phytocystatins regulate various physiological processes in plants, including responses to biotic and abiotic stresses, mainly because they act as inhibitors of cysteine proteases. In this study, we have analyzed four cystatins from Theobroma cacao L. previously identified in ESTs libraries of the interaction with the fungus Moniliophthora perniciosa and named TcCYS1, TcCYS2, TcCYS3 and TcCYS4. The recombinant cystatins were purified and subjected to the heat treatment, at different temperatures, and their thermostabilities were monitored using their ability to inhibit papain protease. TcCYS1 was sensitive to temperatures above 50°C, while TcCYS2, TcCYS3, and TcCYS4 were thermostable. TcCYS4 presented a decrease of inhibitory activity when it was treated at temperatures between 60 and 70°C, with the greater decrease occurring at 65°C. Analyses by native gel electrophoresis and size-exclusion chromatography showed that TcCYS4 forms oligomers at temperatures between 60 and 70°C, co...

Genetics and molecular research : GMR, 2014

Theobroma cacao is a woody and recalcitrant plant with a very high level of interfering compounds... more Theobroma cacao is a woody and recalcitrant plant with a very high level of interfering compounds. Standard protocols for protein extraction were proposed for various types of samples, but the presence of interfering compounds in many samples prevented the isolation of proteins suitable for two-dimensional gel electrophoresis (2-DE). An efficient method to extract root proteins for 2-DE was established to overcome these problems. The main features of this protocol are: i) precipitation with trichloroacetic acid/acetone overnight to prepare the acetone dry powder (ADP), ii) several additional steps of sonication in the ADP preparation and extractions with dense sodium dodecyl sulfate and phenol, and iii) adding two stages of phenol extractions. Proteins were extracted from roots using this new protocol (Method B) and a protocol described in the literature for T. cacao leaves and meristems (Method A). Using these methods, we obtained a protein yield of about 0.7 and 2.5 mg per 1.0 g l...

Cell Metabolism - Cell Homeostasis and Stress Response, 2012

Acta Physiologiae Plantarum, 2015

AbstractAl3+ toxicity is the main limiting factor of T. cacao sustainability in highly weathered ... more AbstractAl3+ toxicity is the main limiting factor of T. cacao sustainability in highly weathered acidic soils in Brazil. However, there is insufficient information on the effects of Al3+ toxicity in cacao. Results showed that, with the increase in Al3+ concentration, ‘Catongo’ × ‘Catongo’ had higher guaiacol peroxidase activity in the leaves, while CCN-10 × SCA-6 had the highest activity in the roots. This resulted in an accumulation of P and K in the stems and K in the roots of ‘Catongo’ × ‘Catongo’, while CCN-10 × SCA-6 accumulated Mg, P and S in the leaves, K in the stems and Fe in the roots. Anatomical analysis of leaf mesophyll showed that CCN-10 × SCA-6 presented increased thickness of the upper epidermis, palisade parenchyma, spongy parenchyma and leaf mesophyll compared to ‘Catongo’ × ‘Catongo’. The increment of Al3+ promotes disruption of leaf cell nuclear membranes, deformity of root epidermis cells, and electrodense material deposits in xylem parenchyma and endodermis cells. Furthermore, rupture of the plasma membrane and vacuole retraction of cortical parenchyma cells (PC) were observed in ‘Catongo’ × ‘Catongo’, while CCN-10 × SCA-6 only experienced rupture of PC cell walls. Furthermore, increased SODcyt expression contributed to the tolerance of CCN-10 × SCA-6 to increased oxidative stress promoted by Al3+. Although an increase in PER-1 gene expression was detected only with the 30 mg Al3+ L−1 dose in ‘Catongo’ × ‘Catongo’ leaves, the increase in GPX activity may have been due to the expression of this gene at a time prior to the collection of plant material for analysis.

Genetics and Molecular Research, 2010

Genetics and Molecular Research, 2012

Sibipiruna (Caesalpinia peltophoroides Benth) is a tree of the Brazilian Atlantic Forest. It is a... more Sibipiruna (Caesalpinia peltophoroides Benth) is a tree of the Brazilian Atlantic Forest. It is a flowering ornamental tree widely planted throughout Brazil and indicated for restoration of degraded areas. We examined protein profile changes in leaves of seedlings of C. peltophoroides grown in nutrient solution under greenhouse conditions, after exposure to cadmium (Cd; 32 mg/L). A two-dimensional gel was used to analyze proteins expressed in response to stress 24 and 72 h after initiation of treatment with Cd. Various protein bands were identified that were related to stress response and/or metabolic adjustments, including proteins involved with resistance to stress, including detoxification, degradation, antioxidant, transport, signal transduction, photosynthesis, electron transport, biosynthesis reactions, and

Acta Botanica Brasilica, 2005

An experiment was conducted with the aim to analyze the effects of soil flooding and leaf positio... more An experiment was conducted with the aim to analyze the effects of soil flooding and leaf position on net primary productivity and whole plant carbon balance of Annona glabra L. (Annonaceae) seedlings, a highly flood-tolerant tree, native to the tropical Americas. All seedlings survived a period of 56 days of flooding without symptoms of stress. Flooding induced significant increments in root, stem and whole-plant biomass (P <0.01), and in the root:shoot mass ratio (P <0.05). Measurements of leaf gas exchange were conducted at days four, 11, 18 and 56 after flooding, on the first (L1), fourth (L4) and seventh (L7) fully expanded leaves from the apex of each seedling. The mean values of stomatal conductance to water vapour (g s) and net photosynthetic rate (A) in the control seedlings were around 0.26 mol m-2s-1 and 8.8 µmol m-2s-1, respectively. Significant reductions (P <0.05) in A were observed from L1 to L7 in controls at all four days of measurements. Reductions in A wi...

New Forests, 2007

... Alyne Oliveira Lavinsky Æ Cristiano De Souza Sant'Ana Æ Marcelo Schramm Mielke ÆAlex-Ala... more ... Alyne Oliveira Lavinsky Æ Cristiano De Souza Sant'Ana Æ Marcelo Schramm Mielke ÆAlex-Alan Furtado De Almeida Æ Fábio Pinto Gomes Æ ... IPEF 33:7378 Hardt E, Pereira-Silva EFL, Zakia MJB, Lima WP (2006) Plantios de restauraçao de Matas ciliares em mineraçoes ...

The Theobroma lethal character Luteus-Pa segregates in a 3:1 ratio, expresses in recessive homozy... more The Theobroma lethal character Luteus-Pa segregates in a 3:1 ratio, expresses in recessive homozygosis, initially inducing leaf chlorosis and finally provoking seedlings death. The objective of this work was to evaluate gas exchange, chlorophyll fluorescence emission, chemical composition and oxidative stress of wild and mutant seedlings resulting from the crosses Pa 30 × Pa 169 and its reciprocal, aiming to elucidate the seedlings death induced by Luteus-Pa. At 15 day after emergence (DAE) differences began to appear between the wild type and mutant. Mutant seedlings showed: (1) lack of photosynthesis and alterations in chloroplast morphology; (2) lower level of three abundant groups of proteins in leaves; (3) decrease in the content of chloroplastidic pigments (4) decrease in peroxidases activities and increase in leaf polyphenol oxidase activity; (5) decrease in carbohydrate and concentration of some nutrients and low dry mass in all plant parts. In leaves of mutant seedlings of both crosses damages occurred in the system responsible for the photochemical phase of photosynthesis. Variations in growth parameters and subsequent seedling death up to 60 DAE were related to exhaustion of cotyledonary reserves, inactive photosynthetic apparatus and oxidative stress.