Physiological, Biochemical, and Transcriptomic Responses of Neolamarckia cadamba to Aluminum Stress.

Aluminum is the most abundant metal of the Earth's crust accounting for 7% of its mass, and release of toxic Al3+ in acid soils restricts plant growth. Neolamarckia cadamba, a fast-growing tree, only grows in tropical regions with acidic soils. In this study, N. cadamba was treated with high concentrations of aluminum under acidic condition (pH 4.5) to study its physiological, biochemical, and molecular response mechanisms against high aluminum stress. High aluminum concentration resulted in significant inhibition of root growth with time in N. cadamba. The concentration of Al3+ ions in the root tip increased significantly and the distribution of absorbed Al3+ was observed in the root tip after Al stress. Meanwhile, the concentration of Ca, Mg, Mn, and Fe was significantly decreased, but P concentration increased. Aluminum stress increased activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase from micrococcus lysodeiktic (CAT), and peroxidase (POD) in the root tip, while the content of MDA was decreased. Transcriptome analysis showed 37,478 differential expression genes (DEGs) and 4096 GOs terms significantly associated with treatments. The expression of genes regulating aluminum transport and abscisic acid synthesis was significantly upregulated; however, the genes involved in auxin synthesis were downregulated. Of note, the transcripts of several key enzymes affecting lignin monomer synthesis in phenylalanine pathway were upregulated. Our results shed light on the physiological and molecular mechanisms of aluminum stress tolerance in N. cadamba.

Optimization and Characterization of Palm Oil-based Nanoemulsion Loaded with Parthenium hysterophorus Crude Extract for Natural Herbicide Formulation.

The present study revealed the optimization of nanoemulsion containing palm oil derivatives and Parthenium hysterophorus L. crude extract (PHCE) as pre-emergence herbicide formulation against Diodia ocimifolia. The nanoemulsion formulation was prepared by high energy emulsification method, and it was optimized by mixture experimental design (MED). From the optimization process, analysis of variance (ANOVA) showed a fit quadratic polynomial model with an optimal formulation composition containing 30.91% of palm kernel oil ester (PKOE), 28.48% of mixed surfactants (Tensiofix and Tween 80, 8:2), 28.32% of water and 12.29% of PHCE. The reading of both experimental and predicted particle size in the verification experiment were acceptable with a residual standard error (RSE) was less than 2%. Under the optimal condition, the smallest particle size obtained was 140.10 nm, and the particle was shown by morphology analysis to be spherical and demonstrated good stability (no phase separation) under centrifugation and different storage conditions (25 ± 5°C and 45°C). Nanoemulsion stored for 60 days exhibits monodisperse emulsion with a slight increase of particle size. The increase in particle size over time might have contributed by Ostwald ripening phenomenon which is shown by a linear graph from Ostwald ripening rate analysis. In the in vitro germination test, P. hysterophorus nanoemulsion (PHNE) was shown to cause total inhibition of D. ocimifolia seed at lower concentration (5 g L-1) as compared to PHCE (10 g L-1). The finding of the research could potentially serve as a platform for the development of palm oil based formulation containing plant crude extract for green weed management.

Drying and reduction in sensitivity to desiccation of seeds of Alibertia edulis: the influence of fruit ripening stage.

The intense environmental degradation in tropical regions suitable for agriculture has decreased native forest populations of plants with important fruits and medicinal properties. Alibertia edulis is a native tree from the Brazilian Cerrado. Knowledge about the effects of drying and storage on the physiological behavior of its seeds may aid in its sustainable exploitation and conservation. The goal of the present study was to determine which fruit ripening stage results in A. edulis seeds with higher tolerance to desiccation, and to investigate the effectiveness of polyethylene glycol (PEG) induced osmotic stress in combination with abscisic acid (ABA) in increasing seed desiccation tolerance during storage. Seeds were dried in activated silica gel (fast) or under ambient conditions (slow). Seeds originating from mid-ripe or fully ripe fruits exhibited better physiological performance than those obtained from green fruits. Slow drying resulted in seeds with high physiological potential. Seeds may be stored for up to 180 days without losing viability when treated with -0.73 MPa PEG without ABA.

Biologic propensities and phytochemical profile of Vangueria madagascariensis J. F. Gmelin (Rubiaceae): an underutilized native medicinal food plant from Africa.

Vangueria madagascariensis (VM), consumed for its sweet-sour fruits, is used as a biomedicine for the management of diabetes and bacterial infections in Africa. The study aims to assess the potential of VM on α -amylase, α -glucosidase, glucose movement, and antimicrobial activity. The antioxidant properties were determined by measuring the FRAP, iron chelating activity, and abilities to scavenge DPPH, HOCl, (∙) OH, and NO radicals. Leaf decoction, leaf methanol, and unripe fruit methanol extracts were observed to significantly inhibit α -amylase. Active extracts against α -glucosidase were unripe fruit methanol, unripe fruit decoction, leaf decoction, and ripe fruit methanol, which were significantly lower than acarbose. Kinetic studies revealed a mixed noncompetitive type of inhibition. Leaf methanolic extract was active against S. aureus and E. coli. Total phenolic content showed a strong significant positive correlation (r = 0.88) with FRAP. Methanolic leaf extract showed a more efficient NO scavenging potential and was significantly lower than ascorbic acid. Concerning (∙) OH-mediated DNA degradation, only the methanol extracts of leaf, unripe fruit, and ripe fruit had IC50 values which were significantly lower than α -tocopherol. Given the dearth of information on the biologic propensities of VM, this study has established valuable primary information which has opened new perspectives for further pharmacological research.

Evaluación de la actividad antioxidante de extractos de Palicourea guianensis (Rubiaceae) / Evaluation of antioxidant activity of Palicourea guianensis (Rubiaceae) extracts

Introducción: la proliferación de radicales libres en el cuerpo humano induce daños oxidativos a las biomoléculas que provocan daños a nivel celular y generan diversas anomalías en el organismo, como arterosclerosis, envejecimiento y cáncer. Actualmente, la búsqueda por moléculas con características antioxidantes es cada vez mayor, donde las plantas representan una de las principales fuentes de compuestos. Objetivo: determinar la actividad antioxidante y el contenido de fenoles de los extractos de diferentes polaridades de la parte aérea de la especie Palicourea guianensis (Rubiaceae). Métodos: para la evaluación de la actividad biológica, se calcularon los valores de concentración media inhibitoria (IC50) de los extractos más activos mediante los métodos de captura de electrones DPPH (2,2-difenil-1-picrilhidracilo) y ABTS (ácido 2,2'azinobis-(3-etilbenzotiazolina)-6-sulfónico). Adicionalmente, se determinó la concentración de fenoles totales presentes en los extractos a través del método de Folin-Ciocalteu. Resultados: los extractos en acetato de etilo (PgAEF) y en agua (PgAF) presentaron mayor actividad antioxidante con valores de IC50 de 5 207 y 3 912 mg/L respectivamente. Asimismo, se observó una relación directamente proporcional entre la concentración de fenoles totales presentes en los extractos y la actividad antioxidante exhibida. Conclusiones: las especies de la familia Rubiaceae, especialmente P. guianensis, son una fuente promisoria e importante de metabolitos secundarios con capacidad antioxidante, por lo cual se requieren de mayores estudios que permitan identificar dichas sustancias e integrarlas a programas de terapia antioxidante en el área de la salud(AU)

Introduction: the proliferation of free radicals in the human body induces oxidative damage to biomolecules that cause damage at the cellular level and can generate various abnormalities in the body, such as atherosclerosis, aging and cancer. Currently, the search for molecules with antioxidant properties is increasing, where the plants are a major source of compounds. Objective: to determine the antioxidant activity and phenolic content of extracts of different polarities from the aerial part of Palicourea guianensis (Rubiaceae) species. Methods: for evaluation of the biological activity, the values of the mean inhibitory concentration (IC50) of the most active extracts were estimated by the methods of electron capture DPPH (2,2-diphenyl-1-picrylhidracyl) and ABTS (2,2'azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid). Additionally, the total phenol concentration present in the extracts was determined using the Folin-Ciocalteu reagent. Results: the extracts in ethyl acetate (PgAEF) and in water (PgAF) showed higher antioxidant activity with IC50 values of 5 207 and 3 912 mg/L respectively. Furthermore, there was direct relationship between the concentration of total phenols present in the extracts and the antioxidant activity. Conclusions: Rubiaceae family species, especially P. guianensis are a promising and important source of secondary metabolites with antioxidant capacity, so further studies are required to identify these substances and integrate them to the antioxidant therapy programs of the health areas(AU)

Green nanoemulsion-laden glyphosate isopropylamine formulation in suppressing creeping foxglove (A. gangetica), slender button weed (D. ocimifolia) and buffalo grass (P. conjugatum).

BACKGROUND: Pesticides are developed with carriers to improve their physicochemical properties and, accordingly, the bioefficacy of the applied formulation. For foliar-applied herbicide, generally less than 0.1% of the active ingredient reaching the target site could reduce pesticide performance. Recently, a carrier of nanoemulsion consisting of oil, surfactant and water, with a particle size of less than 200 nm, has been shown to enhance drug permeability for skin penetration in pharmaceutical delivery systems. In the present work, the aim was to formulate a water-soluble herbicide, glyphosate isopropylamine (IPA), using a green nanoemulsion system for a biological activity study against the weeds creeping foxglove, slender button weed and buffalo grass. RESULTS: The nanoemulsion formulations displayed a significantly lower spray deposition on creeping foxglove (2.9-3.5 ng cm(-2) ), slender button weed (2.6-2.9 ng cm(-2) ) and buffalo grass (1.8-2.4 ng cm(-2) ) than Roundup(®) (3.7-5.1 ng cm(-2) ). The visible injury rates of weeds treated with the nanoemulsion formulations were statistically equivalent to those relating to Roundup(®) at 14 days after treatment, with a control range of 86.67-96.67%. CONCLUSION: It was hypothesised that the significant difference in spray deposition with equal injury rates can be attributed to enhanced bioactivity of the nanoemulsion formulations. This initial discovery could be the platform for developing better penetration of agrochemical formulations in the future.

Compartmentalization and ultrastructural alterations induced by chromium in aquatic macrophytes.

The aim of the present study was to identify the sites of accumulation of Cr in the species of macrophytes that are abundant in the Cachoeira river, namely, Alternanthera philoxeroides, Borreria scabiosoides, Polygonum ferrugineum and Eichhornia crassipes. Plants were grown in nutritive solution supplemented with 0.25 and 50 mg l(-1) of CrCl(3)·6H(2)O. Samples of plant tissues were digested with HNO(3)/HCl in a closed-vessel microwave system and the concentrations of Cr determined using inductively-coupled plasma mass spectrometry (ICP-MS). The ultrastructure of root, stem and leaf tissue was examined using transmission electron microscopy (TEM) and secondary ion mass spectrometry (SIMS) in order to determine the sites of accumulation of Cr and to detect possible alterations in cell organelles induced by the presence of the metal. Chromium accumulated principally in the roots of the four macrophytes (8.6-30 mg kg(-1) dw), with much lower concentrations present in the stems and leaves (3.8-8.6 and 0.01-9.0 mg kg(-1) dw, respectively). Within root tissue, Cr was present mainly in the vacuoles of parenchyma cells and cell walls of xylem and parenchyma. Alterations in the shape of the chloroplasts and nuclei were detected in A. philoxeroides and B. scabiosoides, suggesting a possible application of these aquatic plants as biomarkers from Cr contamination.

Morphophysiological responses and programmed cell death induced by cadmium in Genipa americana L. (Rubiaceae).

Cadmium (Cd) originating from atmospheric deposits, from industrial residues and from the application of phosphate fertilizers may accumulate in high concentrations in soil, water and food, thus becoming highly toxic to plants, animals and human beings. Once accumulated in an organism, Cd discharges and sets off a sequence of biochemical reactions and morphophysiological changes which may cause cell death in several tissues and organs. In order to test the hypothesis that Cd interferes in the metabolism of G. americana, a greenhouse experiment was conducted to measure eventual morphophysiological responses and cell death induced by Cd in this species. The plants were exposed to Cd concentrations ranging from 0 to 16 mg l(-1), in a nutritive solution. In TUNEL reaction, it was shown that Cd caused morphological changes in the cell nucleus of root tip and leaf tissues, which are typical for apoptosis. Cadmium induced anatomical changes in roots and leaves, such as the lignification of cell walls in root tissues and leaf main vein. In addition, the leaf mesophyll showed increase of the intercellular spaces. On the other hand, Cd caused reductions in the net photosynthetic rate, stomatal conductance and leaf transpiration, while the maximum potential quantum efficiency of PS2 (Fv/Fm) was unchanged. Cadmium accumulated in the root system in high concentrations, with low translocation for the shoot, and promoted an increase of Ca and Zn levels in the roots and a decrease of K level in the leaves. High concentrations of Cd promoted morphophysiological changes and caused cell death in roots and leaves tissues of G. americana.

Anti-diarrhoeal activity of crude aqueous extract of Rubia tinctorum L. roots in rodents.

The anti-diarrhoeal effect of aqueous extract of Rubia tinctorum L. (Rubiaceae) roots in rodents was examined. At doses 300, 600 and 800 mg/kg aqueous extract protected rats, in a dose-dependent fashion, against castor oil-induced diarrhoeal dropping by 37, 59 and 64% respectively. Furthermore, it has significantly inhibited by 41% the gastrointestinal transit of charcoal in mice at 800 mg/kg dose of extract. These data suggest that Rubia tinctorum showed antidiarrhoeal activity by inhibiting intestinal motility which was concordant with its use in traditional medicine.

Vertebrate pesticide risk assessment by indigenous communities in New Zealand.

In New Zealand, the vertebrate pesticide sodium fluoroacetate (Compound 1080) is aerially applied in baits for control of the brush-tailed possum Trichosurus vulpecula (Kerr, 1792). Maori, the indigenous people of New Zealand, have raised concerns about 1080 impacts on culturally-important species. Here, we outline two steps taken to help Maori assess 1080 risk. First, field research was undertaken to determine if naturally-occurring plants utilized by a Maori community for food and medicine would take up 1080 from baits. Single baits were placed at the base of individual plants of two species, pikopiko (Asplenium bulbiferum) and karamuramu (Coprosma robusta). Plants were sampled at various times up to 56 days, and samples were analyzed for 1080 content. No 1080 was detected in any of the pikopiko samples, whereas 1080 was detected in karamuramu, at a maximum concentration of 5 ppb after seven days, and 2.5 ppb after 14 days. This concentration decreased to 0 at 28 days, indicating that 1080 was not persistent. The results of the present study suggest there is negligible risk of humans being poisoned by consuming plants that have taken up 1080 from baits. To allay community concerns that minute concentrations of 1080 might influence the medicinal properties of plants, it is suggested that a withholding period of 30 days after 1080 control operations could be adopted. Second, after further consultation we undertook a review of the scientific literature relating to 1080 impacts on additional non-target species of cultural importance to Maori. The information was presented on an interactive foodweb database that allowed the collection and presentation of a large volume of complex information about 1080 in a holistic and pictorial fashion. This database was presented to many Maori communities throughout New Zealand, and feedback was overwhelmingly positive. The database is likely to play a key role in informing these communities about 1080, and is seen as an important new tool to help these communities make their own risk assessments.

Molecular characterization and expression analysis of a new cDNA encoding strictosidine synthase from Ophiorrhiza japonica.

A new full-length cDNA encoding strictosidine synthase (designated as OjSTR, GenBank Accession No. 1087598), which catalyzes a committed step in camptothecin biosynthetic pathway, was isolated from young leaves of Ophiorrhiza japonica for the first time. OjSTR was 1,258 bp and contained a 1,062 bp open reading frame encoding a deduced protein of 353 amino acid residues. Sequence analyses showed that OjSTR had high homology with other STRs from some TIA-producing plants. Phylogenetic tree analysis showed that OjSTR had closest relationship with STR from O. pumila. Tissue expression pattern analysis revealed that OjSTR constitutively expressed in all the tested tissues at different levels, which was high in flower, moderate in leaf and root, low in stem. Expression profiles under plant defense signals such as methyl jasmonate and salicylic acid were investigated, and the results revealed that expression of OjSTR was all induced, implying that OjSTR was high elicitor responsive.

Camptothecin biosynthetic genes in hairy roots of Ophiorrhiza pumila: cloning, characterization and differential expression in tissues and by stress compounds.

Camptothecin derivatives are clinically used anti-tumor compounds that biogenetically belong to a group of monoterpenoid indole alkaloids (TIA). We have already established a hairy root culture of Ophiorrhiza pumila (Rubiaceae) that produces camptothecin. The present study describes the cloning and characterization of cDNAs encoding strictosidine synthase (OpSTR; EC 4.3.3.2) and tryptophan decarboxylase (OpTDC; EC 4.1.1.28), two key enzymes in the biosynthesis of TIA from hairy roots of O. pumila. We also isolated the cDNA coding for NADPH:cytochrome P450 reductase (OpCPR; EC 1.6.2.4) that is presumed to be indirectly involved in camptothecin synthesis. The recombinant OpSTR and OpTDC proteins exhibit STR and TDC activities, respectively, when expressed in Escherichia coli. The tissue-specific and stress-inducible expression patterns of OpSTR and OpTDC were quite similar, unlike those of OpCPR. The high expression of OpSTR and OpTDC observed in hairy roots, roots and stems were closely correlated with STR protein accumulation as observed by immunoblot analysis. Plant stress compounds like salicylic acid repressed expression of OpSTR and OpTDC, suggesting coordinate regulation of these genes for camptothecin biosynthesis.

Effect of salicylic acid, methyl jasmonate, ethephon and cantharidin on anthraquinone production by Rubia cordifolia callus cultures transformed with the rolB and rolC genes.

It has been suggested that the rol genes of Agrobacterium rhizogenes could play an essential role in the activation of secondary metabolite production in plant transformed cultures. This study investigated whether the content of anthraquinone phytoalexins was changed in callus cultures of Rubia cordifolia transgenic for the 35S-rolB and 35S-rolC genes in comparison with a non-transformed callus culture. The anthraquinone content was shown to be significantly increased in transgenic cultures, thus providing further evidence that the rol-gene transformation can be used for the activation of secondary metabolism in plant cells. Methyl jasmonate and salicylic acid strongly increased anthraquinone accumulation in both transgenic and non-transgenic R. cordifolia calluses, whereas ethephon did not. A treatment of the cultures by cantharidin, the protein phosphatase 2A inhibitor, resulted in massive induction of anthraquinone accumulation in the transgenic cultures only. We suggest the involvement of a cantharidin-sensitive protein phosphorylation mechanism in anthraquinone biosynthesis in transgenic cultures.

Auxin herbicides induce H(2)O(2) overproduction and tissue damage in cleavers (Galium aparine L.).

The phytotoxic effects of auxin herbicides, including the quinoline carboxylic acids quinmerac and quinclorac, the benzoic acid dicamba and the pyridine carboxylic acid picloram, were studied in relation to changes in phytohormonal ethylene and abscisic acid (ABA) levels and the production of H(2)O(2) in cleavers (Galium aparine). When plants were root-treated with 10 microM quinmerac, ethylene synthesis was stimulated in the shoot tissue, accompanied by increases in immunoreactive levels of ABA and its precursor xanthoxal. It has been demonstrated that auxin herbicide-stimulated ethylene triggers ABA biosynthesis. The time-course and dose-response of ABA accumulation closely correlated with reductions in stomatal aperture and CO(2) assimilation and increased levels of hydrogen peroxide (H(2)O(2)), deoxyribonuclease (DNase) activity and chlorophyll loss. The latter parameters were used as sensitive indicators for the progression of tissue damage. On a shoot dry weight basis, DNase activity and H(2)O(2) levels increased up to 3-fold, relative to the control. Corresponding effects were obtained using auxin herbicides from the other chemical classes or when ABA was applied exogenously. It is hypothesized, that auxin herbicides stimulate H(2)O(2) generation which contributes to the induction of cell death in Galium leaves. This overproduction of H(2)O(2) could be triggered by the decline of photosynthetic activity, due to ABA-mediated stomatal closure.