RESUMO
The present investigationwas carried out to determine the effect of germination on pasting, rheological, morphological properties of Kodo millet flour and in-vitroantioxidant characteristics of its phenolic and γ-amino butyric acid extracts. Rheological analysis depicted complex flour viscosity decreased with an improvement in shear intensity, symbolizing the shear-thinning action of flour upon germination. The frequency and temperature sweep demonstrated a decrease in visco-elasticity as a result of germination wherein, SEM revealed destruction in the continuous composite structure of starch which got entangled in dense protein matrix following germination. The in-vitroantioxidant activities such as total antioxidant capacity, DPPH*, FRAP, metal chelating ability and hydrogen peroxide scavenging activities of both the extracts increased significantly. There was a decrease in pasting properties and gelatinization behaviour whereas, visco-elastic solid behaviour changed to visco-elastic fluid. This research explores the potential of germinated Kodo millet flour for valuable bioactive compounds extraction and its utilization in product development.
Assuntos
Antioxidantes/metabolismo , Farinha/análise , Germinação , Paspalum/química , Compostos Fitoquímicos/isolamento & purificação , Extratos Vegetais/química , Elasticidade , Paspalum/fisiologia , Fenóis/análise , Reologia , Amido/química , Temperatura , ViscosidadeRESUMO
Salinity is a growing issue worldwide, with nearly 30% of arable land predicted to be lost due to soil salinity in the next 30 years. Many grass crops that are vital to sustain the world's caloric intake are salt sensitive. Studying mechanisms of salt tolerance in halophytic grasses, plants that thrive in salt conditions, may be an effective approach to ultimately improve salt-sensitive grass crops. Seashore paspalum (Paspalum vaginatum) is a halophytic Panicoid grass able to grow in salt concentrations near that of seawater. Despite its widespread cultivation as a sustainable turfgrass, the mechanism underlying its ability to retain high Na+ concentrations in photosynthetic tissue while maintaining growth remains unknown. We examined the leaf structure and ion content in P. vaginatum 'HI10', which shows increased growth under saline conditions, and Paspalum distichum 'Spence', which shows reduced growth under salt, to better understand the superior salt tolerance of cv HI10. A striking difference between cv HI10 and cv Spence was the high steady-state level of K+ in cv HI10. Imaging further showed that the adaxial surface of both cv HI10 and cv Spence contained dense costal ridges of papillae. However, these unicellular extensions of the epidermis were significantly larger in cv HI10 than in cv Spence. The cv HI10 papillae were shown to act as Na+ sinks when plants were grown under saline conditions. We provide evidence that leaf papillae function as specialized structures for Na+ sequestration in P. vaginatum, illustrating a possible path for biotechnological improvement of salt-sensitive Panicoid crops with analogous leaf structures.
Assuntos
Paspalum/química , Paspalum/metabolismo , Folhas de Planta/metabolismo , Tolerância ao Sal/fisiologia , Plantas Tolerantes a Sal/química , Plantas Tolerantes a Sal/metabolismo , Sódio/metabolismo , Variação Genética , Paspalum/genética , Plantas Tolerantes a Sal/genéticaRESUMO
A low-cost Kodo millet bran residue was utilized as feedstock for the production of D (-) lactic acid (DLA) using Lactobacillus delbrueckii NBRC3202 under anaerobic condition. Data culled from a series of batch fermentation processes with different initial Kodo millet bran residue hydrolysate (KMBRH) and DLA concentrations were used for kinetic model development. Both simulated and experimental data were in good agreement for cell growth, KMBRH utilization, and DLA formation. The values of kinetic constants specific growth rate, (µm = 0.17 h-1); growth (αP = 0.96 g.g-1) and non-growth (ßP = 1.19 g.g-1.h-1) associated constant for DLA production and the maximum specific KMBRH utilization rate, (qG, max = 1.18 g.g-1.h-1) were in good agreement with the literature reports. Kinetic analysis elucidated that L. delbrueckii growth was predominantly influenced by KMBRH limitation and highly sensitive to DLA inhibition. Fed-batch fermentation studies demonstrated the existence of substrate and product inhibition paving the scope for process intensification.
Assuntos
Fermentação , Ácido Láctico/metabolismo , Paspalum/química , Sementes/química , Hidrólise , Cinética , Ácido Láctico/química , Lactobacillus delbrueckii/metabolismoRESUMO
Climate change has become a real threat, and its impacts are being felt throughout the world. Temperature is considered one of the significant elements by the recent consequences of climate change and global warming, specially the salinity which is increased at higher temperature. Turfgrasses are adversely affected due to an increasing trend in salinity. The main aim of this investigation was to find out salt-tolerant ecotypes from native species of UAE to mitigate the salinity problem. Performance of a native grass, Aeluropus lagopoides, was investigated under high saline conditions during the year 2014 under the UAE climatic conditions. The experiment was planned under randomised complete block design (RCBD) with two factors and four replications. During the experiment, 50 ecotypes of Aeluropus lagopoides, alongside Paspalum vaginatum (as control), were tested at different salt levels, i.e. 0, 15, 30, 45, 60 and 75 dSm-1. Significant differences were found among various ecotypes as well as salinity levels for different agronomic traits including green cover, canopy stiffness, leaf colour and salinity of leaf rinseates. Most of the ecotypes tolerated salinity up to 30 dSm-1, maintaining the quality, but beyond this level the quality declined. However, some of the ecotypes survived under high salinity, even beyond sea level (75 dSm-1). All the ecotypes, except RUA2, RUA3 and RUA1, showed better performance than P. vaginatum, the prevailing commercial turfgrass in the UAE. Based on their performance, the ecotypes RUDA7, FA5, RA3, RUDA2 and RA2 could be used for turf purposes under saline conditions.
Assuntos
Paspalum/química , Folhas de Planta/química , Ecótipo , Salinidade , TemperaturaRESUMO
ß-glucan extracted from raw and germinated foxtail and kodo millets were evaluated for its functional, rheological and in vitro antioxidant characteristics. The in vitro activity determined in terms of diphenyl-p-picryl hydrazy (DPPH) radical scavenging activity and Ferric reducing antioxidant power (FRAP) activity was found higher in germinated kodo millet (78.74%, 48.98%) compared to foxtail millet (34.96%, 38.67%), respectively. Water binding capacity and swelling power of ß-glucan extract of foxtail millet increased from 2.88â¯g/g to 3.06â¯g/g and 1.32â¯g/g to 1.67â¯g/g and that of kodo millet from 3.45 to 3.99â¯g/g and 2.54 to 2.99â¯g/g, respectively, after germination. There was a significant improvement in foaming capacity and stability of ß-glucan after germination. The 'n' values were less than unity indicated that ß-glucan extracts behaved pseudo-plastic like material. The storage modus (G') of ß-glucan extracts of germinated kodo millet was higher than foxtail millets, as well as overall higher than the loss modulus (Gâ³) indicating a dominantly viscoelastic behaviour and stability. Peak tanδ was lower for germinated foxtail millet compared to kodo millet indicating more stable gel of the former. Therefore, improvements in the functional as well rheological properties of ß-glucan could be exploited in food and pharmaceutical industries.
Assuntos
Antioxidantes/química , Germinação/efeitos dos fármacos , beta-Glucanas/química , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Paspalum/química , Setaria (Planta)/química , beta-Glucanas/isolamento & purificação , beta-Glucanas/farmacologiaRESUMO
This study was initiated to evaluate performance and patterns of cow traits and blood metabolites of 3 breeds of cows grazing bahiagrass (Paspalum notatum Flügge) pastures in central Florida. Purebred cows (n = 411) of either Angus (Bos taurus), Brahman (Bos indicus), or Romosinuano (Bos taurus) breeding, rotationally grazed (moved twice weekly) bahiagrass pastures year-round, and received bahiagrass hay supplemented with molasses and soyhulls or legume hay supplemented with unfortified molasses from October to June each production year. At monthly intervals, all cows were weighed, measured at the hip (HH), scored for BCS, and blood samples collected by jugular puncture from 10 cows per cow breed/block group for plasma urea N (PUN), glucose and non-esterified fatty acids (NEFA). Data were analyzed on cows that calved with a statistical model that included fixed effects of year, cowage, cow breed, month, block, supplement group (n = 2, but not presented), and whether the cow weaned a calf the previous year. Cow was a repeated observation over mo. Three-way interactions involving monthly patterns for cowage x year, year x lactation status the previous year, cowage × cow breed, year × cow breed, and cow breed × lactation status the previous year were significant (P < 0.001) for BW and BCS. The interaction for cowage × month was also significant (P < 0.05) for glucose, and cow breed × month was important (P < 0.01) for PUN, glucose, and NEFA. Important differences included: 1) greater BW and BCS for older cows compared to 3-yr old cows; 2) greater BW and BCS before calving for cows that did not lactate the previous year; 3) PUN levels were above 11 mg/dl except for February, August and September, and was generally greater in tropically adapted breeds; 4) GLU was greatest in Brahman, lowest in Angus, and intermediate in Romosinuano cows; and 5) plasma levels of NEFA escalated at calving and then declined, but Brahman cows maintained greater (P < 0.05) levels from calving until weaning than the other breeds. Cows that lactated the previous year had less NEFA than those that did not lactate. Brahman cows were less fertile than Bos taurus breeds, and weaned heavier calves.
Assuntos
Peso Corporal/fisiologia , Bovinos/fisiologia , Paspalum/química , Aumento de Peso/fisiologia , Envelhecimento , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Composição Corporal , Bovinos/sangue , Dieta/veterinária , Feminino , Florida , Lactação , Masculino , Gravidez , Aumento de Peso/genéticaRESUMO
In south-western Japan, centipedegrass (Eremochloa ophiuroides; CG) offers a novel option for a warm-season perennial for grazing use in areas where bahiagrass (Paspalum notatum; BG) can be grown. However, the potential of CG as a forage has not been fully explored because of the short history as a forage crop. We conducted four experiments to evaluate CG (cv. TifBlair) in comparison with BG (cv. Pensacola) in terms of sward characteristics, nutritive value and choice by animals. In each experiment, four Japanese Black cows (Bos taurus) were individually allowed to graze conterminous monocultures of CG and BG (5 × 10 m each) for 30 min. Irrespective of regrowth durations and fertilizer rates, CG was consistently shorter, leafier and denser, contained lower acid detergent fiber and cellulose, and was preferred or equally selected by cows, as compared with BG. Furthermore, CG maintained sufficient levels of crude protein (80-89 g/kg DM) to ensure voluntary intake of ruminant animals under extended regrowth() and without fertilizer, whereas BG failed to do so (65 g/kg DM). CG provided higher digestible dry matter than BG when crude protein concentration exceeded 86 g/kg DM. The results indicate advantages of CG as a forage.
Assuntos
Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Bovinos/fisiologia , Bovinos/psicologia , Comportamento de Escolha/fisiologia , Herbivoria , Valor Nutritivo , Paspalum , Poaceae , Animais , Celulose/análise , Digestão , Ingestão de Alimentos , Feminino , Paspalum/química , Paspalum/crescimento & desenvolvimento , Proteínas de Plantas/análise , Poaceae/química , Poaceae/crescimento & desenvolvimentoRESUMO
The objective of this study was to evaluate the effects of monensin supplementation on animals receiving warm-season grass with limited supplementation. In Exp. 1, treatments were a factorial combination of 2 stocking rates (1.2 and 1.7 animal unit [AU] [500 kg BW]/ha) and supplementation with monensin (200 mg/d) or control (no monensin) distributed in a complete randomized design with 3 replicates. Thirty Angus × Brahman crossbred heifers (Bos taurus × Bos indicus) with initial BW of 343 ± 8 kg were randomly allocated into 12 bahiagrass (Paspalum notatum) pastures and supplemented with 0.4 kg DM of concentrate (14% CP and 78% TDN) daily for 86 d. Herbage mass (HM) and nutritive value evaluations were conducted every 14 d, and heifers were weighed every 28 d. There was no effect (P ≥ 0.97) of monensin on HM, herbage allowance (HA), and ADG; however, animals receiving monensin had greater (P = 0.03) plasma urea nitrogen (PUN) concentrations. The stocking rate treatments had similar HM in June (P = 0.20) and July (P = 0.18), but the higher stocking rate decreased (P < 0.01) HM and HA during August and September. Average daily gain was greater (P < 0.01) for the pastures with the lower stocking rate in August but not different in July and September (P ≥ 0.15). Gain per hectare tended to be greater on pastures with the higher stocking rate (P ≤ 0.06). In Exp. 2, treatments were 3 levels of monensin (125, 250, and 375 mg/animal per day) and control (no monensin) tested in a 4 × 4 Latin square with a 10-d adaptation period followed by 5 d of rumen fluid collection and total DMI evaluation. Blood samples were collected on d 4 and 5 of the collection period. Ground stargrass (Cynodon nlemfuensis) hay (11.0% CP and 52% in vitro digestible organic matter) was offered daily. The steers received the same supplementation regimen as in Exp. 1. Total DMI was not different among treatments (P = 0.64). There was a linear increase (P ≤ 0.01) in propionate and a tendency for decreased acetate (P ≤ 0.09) concentrations in the rumen with increasing levels of monensin; however, there was no effect (P ≥ 0.19) of monensin levels on ruminal pH and ruminal concentrations of butyrate and ammonia. In addition, there was no effect (P ≥ 0.73) of monensin levels on plasma concentrations of glucose, insulin, IGF-1, and PUN. In summary, monensin supplementation effects were not detected at either stocking rate and may not be effective in increasing performance of beef cattle grazing low-quality warm-season grasses with limited supplementation.
Assuntos
Ração Animal/análise , Bovinos/fisiologia , Cynodon/química , Abrigo para Animais , Monensin/farmacologia , Paspalum/química , Animais , Nitrogênio da Ureia Sanguínea , Feminino , Insulina/sangue , Fator de Crescimento Insulin-Like I , Valor Nutritivo , Ionóforos de Próton/farmacologia , Estações do AnoRESUMO
A meso-scale pilot plant was set up to test the efficiency of a bioremediation scheme applied to marine sediments contaminated by heavy metals and hydrocarbons. The experiment was implemented for three years in two stages using two remediation agents: plants (Paspalum vaginatum and Tamarix gallica) and earthworms (Eisenia fetida). DNA and RNA-based methodologies were applied to elucidate the dynamics of the bacterial population and were related to improving biological and chemical conditions of the sediments. Bioremediation strategies were successful in removing pollutants from the contaminated sediments and specialization within the bacterial community related to the type of contamination present was detected in the different stages of the process. The highest response of Gram-positive PAH-degraders to the contamination was detected at the beginning and after the first stage of the experiment, corresponding to the uppermost values of degradation.
Assuntos
Recuperação e Remediação Ambiental/métodos , Sedimentos Geológicos/química , Oligoquetos/química , Plantas/química , Poluentes Químicos da Água/química , Animais , Biodegradação Ambiental , DNA/química , Monitoramento Ambiental , Bactérias Gram-Positivas/metabolismo , Oligoquetos/metabolismo , Paspalum/química , Paspalum/metabolismo , Plantas/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Reação em Cadeia da Polimerase , Poluentes do Solo/análise , Tamaricaceae/química , Tamaricaceae/metabolismo , Microbiologia da Água , Poluentes Químicos da Água/metabolismoRESUMO
Determination of gene expression is an important tool to study biological processes and relies on the quality of the extracted RNA. Changes in gene expression profiles may be directly related to mutations in regulatory DNA sequences or alterations in DNA cytosine methylation, which is an epigenetic mark. Correlation of gene expression with DNA sequence or epigenetic mark polymorphism is often desirable; for this, a robust protocol to isolate high-quality RNA and DNA simultaneously from the same sample is required. Although commercial kits and protocols are available, they are mainly optimized for animal tissues and, in general, restricted to RNA or DNA extraction, not both. In the present study, we describe an efficient and accessible method to extract both RNA and DNA simultaneously from the same sample of various plant tissues, using small amounts of starting material. The protocol was efficient in the extraction of high-quality nucleic acids from several Arabidopsis thaliana tissues (e.g., leaf, inflorescence stem, flower, fruit, cotyledon, seedlings, root, and embryo) and from other tissues of non-model plants, such as Avicennia schaueriana (Acanthaceae), Theobroma cacao (Malvaceae), Paspalum notatum (Poaceae), and Sorghum bicolor (Poaceae). The obtained nucleic acids were used as templates for downstream analyses, such as mRNA sequencing, quantitative real time-polymerase chain reaction, bisulfite treatment, and others; the results were comparable to those obtained with commercial kits. We believe that this protocol could be applied to a broad range of plant species, help avoid technical and sampling biases, and facilitate several RNA- and DNA-dependent analyses.
Assuntos
DNA de Plantas/isolamento & purificação , Extração Líquido-Líquido/métodos , RNA de Plantas/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/normas , Arabidopsis/química , Arabidopsis/genética , Avicennia/química , Avicennia/genética , Cacau/química , Cacau/genética , Clorofórmio/química , DNA de Plantas/química , DNA de Plantas/genética , Epigênese Genética , Frutas/química , Frutas/genética , Cloreto de Lítio/química , Paspalum/química , Paspalum/genética , Fenol/química , Folhas de Planta/química , Folhas de Planta/genética , Raízes de Plantas/química , Raízes de Plantas/genética , Caules de Planta/química , Caules de Planta/genética , RNA de Plantas/química , RNA de Plantas/genética , Plântula/química , Plântula/genética , Sorghum/química , Sorghum/genéticaRESUMO
BACKGROUND: Bahia grass pollen (BaGP) is a major cause of allergic rhinitis. Subcutaneous allergen-specific immunotherapy is effective for grass pollen allergy, but is unsuitable for patients with moderate to severe asthma due to the risk of anaphylaxis. T cell-reactive but IgE nonreactive peptides provide a safer treatment option. This study aimed to identify and characterize dominant CD4(+) T cell epitope peptides of the major BaGP allergen, Pas n 1. METHODS: Pas n 1-specific T cell lines generated from the peripheral blood of BaGP-allergic subjects were tested for proliferative and cytokine response to overlapping 20-mer Pas n 1 peptides. Cross-reactivity to homologous peptides from Lol p 1 and Cyn d 1 of Ryegrass and Bermuda grass pollen, respectively, was assessed using Pas n 1 peptide-specific T cell clones. MHC class II restriction of Pas n 1 peptide T cell recognition was determined by HLA blocking assays and peptide IgE reactivity tested by dot blotting. RESULTS: Three Pas n 1 peptides showed dominant T cell reactivity; 15 of 18 (83%) patients responded to one or more of these peptides. T cell clones specific for dominant Pas n 1 peptides showed evidence of species-specific T cell reactivity as well as cross-reactivity with other group 1 grass pollen allergens. The dominant Pas n 1 T cell epitope peptides showed HLA binding diversity and were non-IgE reactive. CONCLUSIONS: The immunodominant T cell-reactive Pas n 1 peptides are candidates for safe immunotherapy for individuals, including those with asthma, who are allergic to Bahia and possibly other grass pollens.
Assuntos
Alérgenos/imunologia , Linfócitos T CD4-Positivos/imunologia , Epitopos de Linfócito T/imunologia , Oligopeptídeos/imunologia , Paspalum/imunologia , Proteínas de Plantas/imunologia , Pólen/imunologia , Adulto , Alérgenos/química , Sequência de Aminoácidos , Antígenos de Plantas/química , Antígenos de Plantas/imunologia , Asma/complicações , Asma/tratamento farmacológico , Asma/imunologia , Linfócitos T CD4-Positivos/química , Células Clonais , Reações Cruzadas , Cynodon/química , Cynodon/imunologia , Dessensibilização Imunológica , Epitopos de Linfócito T/química , Feminino , Humanos , Imunoglobulina E/imunologia , Lolium/química , Lolium/imunologia , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Oligopeptídeos/química , Oligopeptídeos/uso terapêutico , Paspalum/química , Proteínas de Plantas/química , Pólen/química , Rinite Alérgica Sazonal/complicações , Rinite Alérgica Sazonal/tratamento farmacológico , Rinite Alérgica Sazonal/imunologiaRESUMO
This study was designed to identify physiological responses and differential proteomic responses to salinity stress in roots of a salt-tolerant grass species, seashore paspalum (Paspalum vaginatum), and a salt-sensitive grass species, centipedegrass (Eremochloa ophiuroides). Plants of both species were exposed to salinity stress by watering the soil with 300 mM NaCl solution for 20 d in a growth chamber. The 2-DE analysis revealed that the abundance of 8 protein spots significantly increased and 14 significantly decreased in seashore paspalum, while 19 and 16 protein spots exhibited increase and decrease in abundance in centipedegrass, respectively. Eight protein spots that exhibited enhanced abundance in seashore paspalum under salinity stress were subjected to mass spectrometry analysis. Seven protein spots were successfully identified, they are peroxidase (POD, 2.36-fold), cytoplasmic malate dehydrogenase (cMDH, 5.84-fold), asorbate peroxidase (APX, 4.03-fold), two mitochondrial ATPSδ chain (2.26-fold and 4.78-fold), hypothetical protein LOC100274119 (5.01-fold) and flavoprotein wrbA (2.20-fold), respectively. Immunblotting analysis indicated that POD and ATPSδ chain were significantly up-regulated in seashore paspalum at 20 d of salinity treatment while almost no expression in both control and salt treatment of centipedegrass. These results indicated that the superior salinity tolerance in seashore paspalum, compared to centipedegrass, could be associated with a high abundance of proteins involved in ROS detoxification and energy metabolism.
Assuntos
Paspalum/metabolismo , Raízes de Plantas/metabolismo , Poaceae/metabolismo , Cloreto de Sódio/farmacologia , Adaptação Fisiológica , China , Paspalum/química , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Raízes de Plantas/química , Poaceae/química , Espécies Reativas de Oxigênio/metabolismo , Salinidade , Tolerância ao Sal/fisiologia , Estresse FisiológicoRESUMO
BACKGROUND: Group 1 grass pollen allergens are glycoproteins of the ß-expansin family. They are a predominant component of pollen and are potent allergens with a high frequency of serum IgE reactivity in grass pollen-allergic patients. Bahia grass is distinct from temperate grasses and has a prolonged pollination period and wide distribution in warmer climates. Here we describe the purification of the group 1 pollen allergen, Pas n 1, from Bahia grass (Paspalum notatum), an important subtropical aeroallergen source. METHODS: Pas n 1 was purified from an aqueous Bahia grass pollen extract by ammonium sulphate precipitation, hydrophobic interaction and size exclusion chromatography, and assessed by one- and two-dimensional gel electrophoresis, immunoblotting and ELISA. RESULTS: Pas n 1 was purified to a single 29-kDa protein band containing two dominant isoforms detected by an allergen-specific monoclonal antibody and serum IgE of a Bahia grass pollen-allergic donor. The frequency of serum IgE reactivity with purified Pas n 1 in 51 Bahia grass pollen-allergic patients was 90.6%. Serum IgE reactivity with purified Pas n 1 was highly correlated with serum IgE reactivity with Bahia grass pollen extract and recombinant Pas n 1 (r = 0.821 and 0.913, respectively). CONCLUSIONS: Pas n 1 is a major allergen reactive at high frequency with serum IgE of Bahia grass pollen-allergic patients. Purified natural Pas n 1 has utility for improved specific diagnosis and immunotherapy for Bahia grass pollen allergy.
Assuntos
Alérgenos/isolamento & purificação , Antígenos de Plantas/isolamento & purificação , Paspalum/imunologia , Pólen/química , Pólen/imunologia , Alérgenos/química , Alérgenos/imunologia , Antígenos de Plantas/química , Antígenos de Plantas/imunologia , Eletroforese em Gel Bidimensional , Ensaio de Imunoadsorção Enzimática , Humanos , Immunoblotting , Imunoglobulina E/imunologia , Paspalum/química , Proteínas de Plantas/química , Proteínas de Plantas/imunologia , Proteínas de Plantas/isolamento & purificação , Rinite Alérgica Sazonal/imunologiaRESUMO
The effects of dark chilling on the leaf-side-specific regulation of photosynthesis were characterized in the C(4) grass Paspalum dilatatum. CO(2)- and light-response curves for photosynthesis and associated parameters were measured on whole leaves and on each leaf side independently under adaxial and abaxial illumination before and after plants were exposed to dark chilling for one or two consecutive nights. The stomata closed on the adaxial sides of the leaves under abaxial illumination and no CO(2) uptake could be detected on this surface. However, high rates of whole leaf photosynthesis were still observed because CO(2) assimilation rates were increased on the abaxial sides of the leaves under abaxial illumination. Under adaxial illumination both leaf surfaces contributed to the inhibition of whole leaf photosynthesis observed after one night of chilling. After two nights of chilling photosynthesis remained inhibited on the abaxial side of the leaf but the adaxial side had recovered, an effect related to increased maximal ribulose-1,5-bisphosphate carboxylation rates (V(cmax)) and enhanced maximal electron transport rates (J(max)). Under abaxial illumination, whole leaf photosynthesis was decreased only after the second night of chilling. The chilling-dependent inhibition of photosynthesis was located largely on the abaxial side of the leaf and was related to decreased V(cmax) and J(max), but not to the maximal phosphoenolpyruvate carboxylase carboxylation rate (V(pmax)). Each side of the leaf therefore exhibits a unique sensitivity to stress and recovery. Side-specific responses to stress are related to differences in the control of enzyme and photosynthetic electron transport activities.
Assuntos
Paspalum/metabolismo , Paspalum/efeitos da radiação , Fotossíntese , Estômatos de Plantas/metabolismo , Dióxido de Carbono/metabolismo , Temperatura Baixa , Escuridão , Cinética , Paspalum/química , Paspalum/enzimologia , Fosfoenolpiruvato Carboxilase/metabolismo , Folhas de Planta/química , Folhas de Planta/enzimologia , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Proteínas de Plantas/metabolismo , Estômatos de Plantas/química , Estômatos de Plantas/efeitos da radiação , Ribulosefosfatos/metabolismoRESUMO
Kodo millet (Paspalum scrobiculatum L.) is a staple food of some sections of people of North India. Consumption of Kodo millet is often found to cause intoxication and poisoning. The grains are frequently infested with Aspergillus tamarii Kita, which produced substantial amount of a mycotoxin, cyclopiazonic acid (CPA). Investigations were carried out to evaluate the hepatotoxic/preneoplastic changes in rat liver following single and multiple dose administration of CPA. Results showed a marked increase in the activity of glutamate pyruvate transaminase (GPT) and glutamate oxaloacetate transaminase (GOT) following CPA exposures, suggesting acute hepatotoxicity. Significant increase was also observed in gamma glutamyl transpeptidase (GGT) activity following CPA exposures, indicating preneoplastic changes in the liver. The results reveal that Kodo poisoning might cause acute hepatotoxicity in men and animals. The findings thus suggest that the consumption of contaminated Kodo millet is a serious health hazard due to exposure to CPA produced by Aspergillus tamarii associated with the millet.
Assuntos
Doença Hepática Induzida por Substâncias e Drogas/etiologia , Indóis/intoxicação , Paspalum/intoxicação , Intoxicação por Plantas/etiologia , Animais , Aspergillus , Relação Dose-Resposta a Droga , Contaminação de Alimentos , Humanos , Indóis/administração & dosagem , Indóis/química , Masculino , Paspalum/química , Paspalum/microbiologia , Ratos , Ratos WistarRESUMO
Fatty acid synthase (FAS) has been identified as a potential antifungal target. FAS prepared from Saccharomyces cerevisiae was employed for bioactivity-guided fractionation of Chlorophora tinctoria,Paspalum conjugatum, Symphonia globulifera, Buchenavia parviflora, and Miconia pilgeriana. Thirteen compounds (1-13), including three new natural products (1, 4, 12), were isolated and their structures identified by spectroscopic interpretation. They represented five chemotypes, namely, isoflavones, flavones, biflavonoids, hydrolyzable tannin-related derivatives, and triterpenoids. 3'-Formylgenistein (1) and ellagic acid 4-O-alpha-l-rhamnopyranoside (9) were the most potent compounds against FAS, with IC(50) values of 2.3 and 7.5 microg/mL, respectively. Furthermore, 43 (14-56) analogues of the five chemotypes from our natural product repository and commercial sources were tested for their FAS inhibitory activity. Structure-activity relationships for some chemotypes were investigated. All these compounds were further evaluated for antifungal activity against Candida albicans and Cryptococcus neoformans. Although there were several antifungal compounds in the set, correlation between the FAS inhibitory activity and antifungal activity could not be defined.
Assuntos
Antifúngicos/isolamento & purificação , Inibidores Enzimáticos/isolamento & purificação , Ácido Graxo Sintases/antagonistas & inibidores , Isoflavonas/isolamento & purificação , Plantas Medicinais/química , Saccharomyces cerevisiae/enzimologia , Taninos/isolamento & purificação , Triterpenos/isolamento & purificação , Antifúngicos/química , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Combretaceae/química , Cryptococcus neoformans/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Concentração Inibidora 50 , Isoflavonas/química , Isoflavonas/farmacologia , Melastomataceae/química , Estrutura Molecular , Moraceae/química , Paspalum/química , Relação Estrutura-Atividade , Taninos/química , Taninos/farmacologia , Triterpenos/química , Triterpenos/farmacologiaRESUMO
Both Fankou and Lechang lead/zinc (Pb/Zn) mine tailings located at Guangdong Province contained high levels of total and DTPA-extractable Pb, Zn and Cu. Paspalum distichum and Cynodon dactylon were dominant species colonized naturally on the tailings. Lead, zinc and copper accumulation and tolerance of different populations of the two grasses growing on the tailings were investigated. Tillers of these populations including those from an uncontaminated area were subjected to the following concentrations: 5, 10, 20, 30 and 40 mg l(-1) Pb, 2.5, 5, 10, 20 and 30 mg (l-1) Zn, or 0.25, 0.50, 1 and 2 mg l(-1) Cu for 14 days, respectively, then tolerance index (TI) and EC50 (the concentrations of metals in solutions which reduce 50% of normal root growth) were calculated. The results indicated that both Lechang and Fankou populations of the two grasses showed a greater tolerance to the three metals than those growing on the uncontaminated area, which suggested that co-tolerant ecotypes have evolved in the two grasses. P. distichum collected from Fankou tailings had the highest tolerance to Cu while Lechang population the highest tolerance to Pb and Zn among the tested populations, and tolerance levels in P. distichum were related to metal concentrations in the plants. P. distichum had a better growth performance than C. dactylon when both of them were grown on the tailings sites. Tolerant populations of these species would serve as potential candidates for re-vegetation of wastelands contaminated with Pb, Zn and Cu.