Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “root development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,765 records · Page 98Linked to original sources
PubMed2000

[Changes in composition and appropriate nutrition of family diet in the metropolitan areas of Brazil (1988-1996)].

OBJECTIVE: A new family budget survey carried out in the mid-nineties in Brazil allows an update of the secular trends (1962-1988) of dietary patterns of Brazilian population living in metropolitan areas. METHODS: Data sources are IBGE Institute of Statistics family budget surveys carried out from March 1987 to February 1988 (13,611 households) and from October 1995 to September 1996 (16,014 households) in all metropolitan areas of Brazil. The daily food availability per capita for each household was calculated dividing the total food acquired in a month by the number of individuals living in a household and the month's number of days. Dietary patterns were characterized according to the amount of selected food groups and nutrients relative to the diet caloric input. Comparisons between the two surveys included the metropolitan area population as a whole and subgroups from less (North and Northeast) and more developed (Mid-west, Southeast and South) regions. RESULTS: It was observed an increase in consumption of meat and dairy products (except for butter) and a reduction in eggs consumption in both less and more developed regions. Beans, roots and tubers consumption showed a steady decline in the whole country while cereals consumption remained the same (higher in developed regions) or had a slight increase (in less developed regions). The proportional consumption of vegetal oils and margarine remained constant in the less developed regions but their consumption was greatly reduced in the more developed ones. CONCLUSIONS: An increase in the diet's lipid content in less developed regions and of saturated fat in the country as a whole, associated with a decrease or even no consumption of beans, vegetables, fruits and complex carbohydrates, and a further increase in the excessive sugar consumption are the negative aspects of the trend observed from 1988 to 1996. Changes that may indicate a growing awareness of the population toward a healthier diet, such as a decline in egg intake and a slight reduction in diets with a high total lipid content, were found only in more developed regions.

Brazil↗
PubMed2006

Relationship between circulating plasma matrix metalloproteinase-9 (gelatinase-B) concentration and aortic root dilatation.

BACKGROUND: Expression of matrix metalloproteinase (MMP) has been shown in aortic dissection and aneurysms indicating increased proteolysis compared with the normal aorta. However, its role in the development of aortic root dilatation has not been studied. We therefore attempted to determine the relationship between aortic root diameter and MMP-9 concentration in a hypertensive population. METHODS: The 53 hypertensive patients with (n = 27) and without aortic dilatation (n = 26) were included in the study. All participants underwent a complete transthoracic echocardiographic examination including aortic root measurement. Plasma concentration of MMP-9 were determined by the one-step sandwich enzyme immunoassay method and compared in both groups. RESULTS: Baseline demographic properties were similar in both groups. No subject had significant valvular disorder and wall motion abnormality on echocardiographic evaluation. On echocardiographic examination only five patients had bicuspid aortic valve. In patients with aortic root dilatation, 21 patients were using an antihypertensive agent, whereas in patients without aortic root dilatation, 19 patients were using an antihypertensive agent. Plasma MMP-9 level was significantly higher in patients with aortic root dilatation than in those without dilatation (2.5 +/- 1.0 v 1.6 +/- 0.9 ng/mL; P = .003). On correlation analysis, we found a positive correlation between aortic diameter and plasma MMM-9 levels (r = 0.43, P = .001). CONCLUSIONS: Aortic root dilatation is associated with higher MMP release, which may indicate the role of increased collagenolytic and elastolytic activities in hypertension-induced aortic root dilatation.

Aged↗
PubMed2005

Genetic transformation of Tylophora indica with Agrobacterium rhizogenes A4: growth and tylophorine productivity in different transformed root clones.

We have developed an efficient transformation system for Tylophora indica, an important medicinal plant in India, using Agrobacterium rhizogenes strains LBA9402 and A4 to infect excised leaf and stem explants and intact shoots at different sites. The induction of callus and transformed roots was dependent on the bacterial strain, explant type and inoculation site used. Transformed roots were induced only in explants infected with A. rhizogenes strain A4, while an optimal transformation frequency of up to 60% was obtained with intact shoots inoculated at the nodes. The presence of the left-hand transferred DNA (T(L)-DNA) in the genome of T. indica roots induced by A. rhizogenes was confirmed by PCR amplification of the rooting locus genes of A. rhizogenes. Root growth and the production of tylophorine, the major alkaloid of the plant, varied substantially among the nine root clones studied. Both parameters increased over time in liquid cultures, with maximum biomass and tylophorine accumulation occurring within 4-6 weeks of growth in fresh medium. Interestingly, in liquid culture, the culture medium also accumulated tylophorine up to concentrations of 9.78+/-0.21 mg l(-1).

Alkaloids↗
PubMed1996

Differential proton secretion in the apical elongation zone caused by gravistimulation is induced by a signal from the root cap.

The extracellular proton activity along primary roots of Phleum pratense L. was measured using proton-selective microelectrodes. Removal of the root cap caused a reduction of the proton influx in the transitional region between the meristem and the apical elongation zone of the vertical root and inhibited the development of pH differences between the physically upper and lower flanks of the gravistimulated root. Disruption of the actin filament system of the root with 5 mmol m-3 cytochalasin D did not result in an altered proton flux and pH pattern compared with untreated vertical control roots, but inhibited the gravity-induced development of pH differences between the physically upper and lower root flanks as well as gravitropic curvature. These results provide evidence that pH changes following gravistimulation are induced by a signal transmitted from the root cap and that the actin filament system is involved in the gravity perception/transduction mechanism.

Cytochalasin D↗
PubMed1997

Expression of cell cycle genes during Sesbania rostrata stem nodule development.

Upon infection of Sesbania rostrata with Azorhizobium caulinodans, nodules are formed on roots and stems. Stem nodules develop from abundantly distributed dormant root primordia. To acquire more insight into the meristem organization during stem nodule development, the expression patterns of a mitotic B1-type cyclin gene (Sesro; CycB1;1), a cyclin-dependent kinase gene (Cdc-2-1Sr), and a histone H4 gene (H4-1Sr) of S. rostrata were followed by in situ hybridization. Cdc2-1Sr transcripts were found in all cells of uninfected and infected root primordia. In uninfected root primordia, Sesro;CycB1;1 transcripts were detected in a few cells of the apical root meristem whereas H4-1Sr transcripts were abundant in this region. Interestingly, after inoculation with A. caulinodans, H4-1Sr transcripts disappeared in the root meristem and a patchy pattern of Sesro;CycB1;1 and H4-1Sr expression appeared in the cortex of the root primordium, reflecting the formation of globular nodule primordia. When bacterial invasion started, a distal nodule meristem was delimited wherein Sesro;CycB1;1 and H4-1Sr expression was concentrated. Approximately 1 week after inoculation, meristem activity ceased, indicated by the loss of Sesro;CycB1;1 and H4-1Sr expression.

Amino Acid Sequence↗
PubMed1991

Quantitative autoradiographic localisation of [125I]endothelin-1 binding sites in spinal cord and dorsal root ganglia of the rat.

The autoradiographic distribution of [125I] endothelin (ET)-1 binding sites was studied in the spinal cord and dorsal root ganglia of developing and adult rat. In the spinal cord, high density of [125I]ET-1 binding sites were diffusely distributed throughout the grey matter whereas in the ganglia discrete silver grains were localised primarily on the satellite cells. A variation in the density of binding sites was evident, particularly in the spinal cord, during development. These data, in conjunction with other reports, suggest a possible neuromodulatory role for ET-1 in spinal cord and dorsal root ganglia of the rat.

Animals↗
PubMed2005

Partial flooding enhances aeration in adventitious roots of black willow (Salix nigra) cuttings.

Black willow (Salix nigra) cuttings are used for streambank stabilization where they are subjected to a range of soil moisture conditions including flooding. Flooding has been shown to adversely impact cutting performance, and improved understanding of natural adaptations to flooding might suggest handling and planting techniques to enhance success. However, data assessing the root aeration in adventitious roots that are developed on cuttings of woody species are scant. In addition, it appears that no data are available regarding aeration of the root system under partially flooded conditions. This experiment was designed to examine the effects of continuous flooding (CF) and partial flooding (PF) on aerenchyma formation and radial oxygen loss (ROL) in black willow cuttings. Photosynthetic and growth responses to these conditions were also investigated. Under laboratory condition, replicated potted cuttings were subjected to three treatments: no flooding (control, C), CF, and PF. Water was maintained above the soil surface in CF and at 10 cm depth in PF. Results indicated that after the 28-d treatments, root porosity ranged between 28.6% and 33.0% for the CF and C plants but was greater for the PF plants (39.2% for the drained and 37.2% for the flooded portions). A similar response pattern was found for ROL. In addition, CF treatment led to decreases in final root biomass and root/shoot ratio. Neither CF nor PF had any detectable adverse effects on plant gas exchange or photosystem II functioning. Our results indicated that S. nigra cuttings exhibited avoidance mechanisms in response to flooding, especially the partially flooded condition which is the most common occurrence in riparian systems.

Oxygen↗
PubMed1991

Histological characterization of bleaching-induced external root resorption in dogs.

External root resorption occasionally develops after intracoronal bleaching with hydrogen peroxide. In this study, an experimental model was established to study thermocatalytic bleaching-induced root resorption in dogs. Histological examination after 6 months revealed that 18% of the teeth had root resorption lesions. The lesions could be divided into three types. In type I, root excavations were associated with a dense inflammatory cell infiltrate. Type II lesions were characterized by granulation tissue formation. In type III, the lesions were filled with reparative cementum. The three types probably represent different phases of one process. Calcium hydroxide had no effect on the occurrence or type of resorption. The instability of hydrogen peroxide and the presence of inflammatory resorption lesions 6 months postoperatively suggest hydrogen peroxide-induced toxic radicals or denaturants as potential irritants.

Animals↗
PubMed1985

Peroxidase Activity in Relation to Suberization and Respiration in White Spruce (Picea glauca [Moench] Voss) Seedling Roots.

Peroxidase (EC 1.11.1.7) activity is associated with suberization during endodermal development and metacutization in roots of white spruce (Picea glauca [Moench] Voss) seedlings. Histochemical analysis indicates a relationship between suberization and peroxidase activity, but peroxidase is ubiquitous. Increased peroxidase activity results from the induction of four anodic peroxidase isozymes in addition to quantitative increases in two anodic peroxidase isozymes. Four of these polymerized eugenol. Cold temperatures induce formation of two anodic isozymes and result in suberization. The increased peroxidase activity associated with suberization is correlated to residual respiration. In an attempt to elucidate this relationship, the effect of respiratory inhibitors on respiration and peroxidase activity are compared.

Journal Article↗
PubMed2003

Comparative characterization of peanuts grown by aquatic floating cultivation and field cultivation for seed and resveratrol production.

Peanut pods (Tainan 12, a Spanish cultivar, Arachis hypogaea L.) have been obtained from peanuts grown in a newly developed aquatic floating cultivation system without artificial aeration or periodic renewal of the solution. The system provided a convenient status for examination of root and pod development. Compared to field-grown peanuts of the same cultivar, the aquatic-cultivated peanut pods and seeds were smaller, whereas seed/pod weight ratios, crude fat and protein contents, and SDS-PAGE protein patterns varied within similar ranges. During cultivation, the highest detected temperature of the aquatic solution was higher than the field-soil temperature. After gas chromatographic analysis of the fatty acid compositions, the oleic acid/linoleic acid ratio of the aquatic-cultivated seeds was higher than that of field-cultivated ones. When the peanut roots were collected, cleaned, dried, weighed, pulverized, and subjected to resveratrol analysis, dry root weights were 4.2 +/- 0.1 and 2.2 +/- 1.1 g/plant and resveratrol contents were 0.074 +/- 0.009 and 0.114 +/- 0.212 mg/g for the aquatic- and field-cultivated peanut roots, respectively. This indicates that the aquatic-cultivated peanut roots could be a potent and consistent source of resveratrol.

Agriculture↗
PubMed2004

Microtubule-associated protein 1B controls directionality of growth cone migration and axonal branching in regeneration of adult dorsal root ganglia neurons.

During development, microtubule-associated protein 1B (MAP1B) is one of the earliest MAPs, preferentially localized in axons and growth cones, and plays a role in axonal outgrowth. Although generally downregulated in the adult, we have shown that MAP1B is constitutively highly expressed in adult dorsal root ganglia (DRGs) and associated with central sprouting and peripheral regeneration of these neurons. Mutant mice with a complete MAP1B null allele that survive until adulthood exhibit a reduced myelin sheath diameter and conductance velocity of peripheral axons and lack of the corpus callosum. Here, to determine the function of MAP1B in axonal regeneration, we used cultures of adult DRG explants and/or dissociated neurons derived from this map1b-/- mouse line. Whereas the overall length of regenerating neurites lacking MAP1B was similar to wild-type controls, our analysis revealed two main defects. First, map1b-/- neurites exhibited significantly (twofold) higher terminal and collateral branching. Second, the turning capacity of growth cones (i.e., "choice" of a proper orientation) was impaired. In addition, lack of MAP1B may affect the post-translational modification of tubulin polymers: quantitative analysis showed a reduced amount of acetylated microtubules within growth cones, whereas the distribution of tyrosinated or detyrosinated microtubules was normal. Both growth cone turning and axonal branch formation are known to involve local regulation of the microtubule network. Our results demonstrate that MAP1B plays a role in these processes during plastic changes in the adult. In particular, the data suggest MAP1B implication in the locally coordinated assembly of cytoskeletal components required for branching and straight directional axon growth.

Animals↗
PubMed1996

cDNA cloning and characterisation of a maize homologue of the MCM proteins required for the initiation of DNA replication.

A central question in cell cycle regulation is how DNA replication is initiated and executed only once in each cell cycle. The cell cycle-regulated assembly of specific initiation protein complexes at chromosomal origins appears to specify the initial sites and timing of DNA replication, and to restrict this process to only one round in the somatic cell cycle. Among the enzymes involved in origin activation, the MCM proteins play a conserved key role. In particular, MCM3 homologues have been shown to be components of the DNA replication licensing activity in yeast and vertebrates. In spite of our detailed knowledge of the regulation of the initiation of DNA synthesis in yeast, there is virtually no information available on the molecules involved in origin activation in higher plants. We have isolated a cDNA from maize root apices, termed ROA (Replication Origin Activator), encoding a protein which shares a high degree of homology with the MCM3 subfamily of MCM proteins. Analysis of gene organisation by Southern blotting shows 2-4 copies per haploid genome of closely related ROA sequences and the presence of further less related sequences in a multigene family. The steady-state levels of ROA mRNA are under developmental control, being relatively high in proliferative tissues such as the root apex, the developing cob and the coleoptile, and are strongly correlated with that of the histone H4 transcript. In situ hybridisation analysis in the root apex reveals that ROA mRNA expression is limited to specific subpopulations of cycling cells, which is typical of cell cycle-regulated expression. The isolation of nearly identical sequences from barley and Arabidopsis by the polymerase chain reaction indicates that MCM-related proteins are conserved in higher plants.

Amino Acid Sequence↗
PubMed1985

Development of sensory and reflex responses to tooth-pulp stimulation in children.

Electric stimulation was applied to the tooth-pulp and tongue in 12 children divided into 3 groups according to the development of the roots of the upper first incisors, i.e. 1/2, 3/4 and fully formed. The masseter inhibitory periods (MIP) could be evoked by electric stimulation of the tongue at sensory threshold current levels in all children, but only for incisors with fully-formed roots. Stimulation of incisors with 3/4 formed roots at detection-threshold currents produced sensation 56 per cent of the time and detectable MIP on 65 per cent of stimuli. No sensation was obtained with stimuli up to 100 microA in incisors with 1/2-formed roots, but MIP was recorded with 31 per cent of stimuli. The findings indicate that reflex activity precedes sensation in the normal development of teeth, and that segmental, reflex, connections appear to be established before the cortical, sensory, projections are fully functional.

Child↗
PubMed2004

Recognition events in AM symbiosis: analysis of fungal gene expression at the early appressorium stage.

Arbuscular mycorrhizal symbiosis is induced upon a series of recognition events involving the reorganization of both plant and fungal cellular programs culminating in the formation of appressoria on the epidermal root cells. In this work we monitored for the first time the genetic changes occurring in the fungal partner during early appressorium development. We established an in vitro system of Glomus mosseae and Petroselinum crispum for studying appressorium formation and found that after 120 h first appressoria developed in the root epidermis. We have constructed a fungal subtractive suppressive library enriched in genes up-regulated at this stage. Our aim was to identify early signaling events during plant recognition leading to appressoria formation. The library contains 375 clones with an average size of 500 bp. From these, 200 clones were sequenced and most of them represent gene fragments with no known homologues (63%) and therefore putative new genes specific to the mycorrhiza symbiosis. Reverse-Northern blot and RT-PCR analyses confirmed that ca. 30% of the genes present in the library were up-regulated upon plant induction after 120 h. Among the genes with homologues in other organisms we found several genes common to other plant-microbe interactions including some genes related to Ca2+-dependent signaling. The up-regulation of these genes opens the possibility that Ca2+ plays a role in the early stages of mycorrhiza formation as it has been found in other plant-microbe interactions such as the Rhizobium symbiosis or the Magnaporthe grisea/rice pathogenic interaction.

Blotting, Northern↗
PubMed2002

Phosphate availability alters architecture and causes changes in hormone sensitivity in the Arabidopsis root system.

The postembryonic developmental program of the plant root system is plastic and allows changes in root architecture to adapt to environmental conditions such as water and nutrient availability. Among essential nutrients, phosphorus (P) often limits plant productivity because of its low mobility in soil. Therefore, the architecture of the root system may determine the capacity of the plant to acquire this nutrient. We studied the effect of P availability on the development of the root system in Arabidopsis. We found that at P-limiting conditions (<50 microM), the Arabidopsis root system undergoes major architectural changes in terms of lateral root number, lateral root density, and primary root length. Treatment with auxins and auxin antagonists indicate that these changes are related to an increase in auxin sensitivity in the roots of P-deprived Arabidopsis seedlings. It was also found that the axr1-3, axr2-1, and axr4-1 Arabidopsis mutants have normal responses to low P availability conditions, whereas the iaa28-1 mutant shows resistance to the stimulatory effects of low P on root hair and lateral root formation. Analysis of ethylene signaling mutants and treatments with 1-aminocyclopropane-1-carboxylic acid showed that ethylene does not promote lateral root formation under P deprivation. These results suggest that in Arabidopsis, auxin sensitivity may play a fundamental role in the modifications of root architecture by P availability.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1992

Nodules Initiated by Rhizobium meliloti Exopolysaccharide Mutants Lack a Discrete, Persistent Nodule Meristem.

Infection of alfalfa with Rhizobium meliloti exo mutants deficient in exopolysaccharide results in abnormal root nodules that are devoid of bacteria and fail to fix nitrogen. Here we report further characterization of these abnormal nodules. Tightly curled root hairs or shepherd's crooks were found after inoculation with Rm 1021-derived exo mutants, but curling was delayed compared with wild-type Rm 1021. Infection threads were initiated in curled root hairs by mutants as well as by wild-type R. meliloti, but the exo mutant-induced threads aborted within the peripheral cells of the developing nodule. Also, nodules elicited by Rm 1021-derived exo mutants were more likely to develop on secondary roots than on the primary root. In contrast with wild-type R. meliloti-induced nodules, the exo mutant-induced nodules lacked a well defined apical meristem, presumably due to the abortion of the infection threads. The relationship of these findings to the physiology of nodule development is discussed.

Journal Article↗
PubMed2003

The effect of plants on the degradation and toxicity of petroleum contaminants in soil: a field assessment.

A field project located at the US Naval Base at Port Hueneme, California was designed to evaluate changes in contaminant concentrations and toxicity during phytoremediation. Vegetated plots were established in petroleum (diesel and heavy oil) contaminated soil and were evaluated over a two-year period. Plant species were chosen based on initial germination studies and included native California grasses. The toxicity of the impacted soil in vegetated and unvegetated plots was evaluated using Microtox, earthworm, and seed germination assays. The reduction of toxicity was affected more by contaminant aging than the establishment of plants. However, total petroleum hydrocarbon concentrations were lower by the end of the study in the vegetated plots when compared to the unvegetated soil. Although phytoremediation is an effective approach for cleaning-up of petroleum contaminated soil, a long-term management plan is required for significant reductions in contaminant concentrations.

Bacteria↗
PubMed2003

The promoter of the asi gene directs expression in the maternal tissues of the seed in transgenic barley.

The bifunctional alpha-amylase/subtilisin inhibitor (BASI) is an abundant protein in barley seeds, proposed to play multiple and apparently diverse roles in regulation of starch hydrolysis and in seed defence against pathogens. In the Triticeae, the protein has evolved the ability to specifically inhibit the main group of alpha-amylases expressed during germination of barley and encoded by the amyl gene family found only in the Triticeae. The expression of the asi gene that encodes BASI has been reported to be controlled by the hormones abscisic acid (ABA) and gibberellic acid (GA). Despite many studies at the gene and protein level, the function of this gene in the plant remains unclear. In this study, the 5'-flanking region (1033 bp, 1033-asi promoter) and the 3'-flanking region (655 bp) of the asi gene were isolated and characterised. The 1033-asi promoter sequence showed homology to a number of ciselements that play a role in ABA and GA regulated expression of other genes. With a green fluorescent protein gene (gfp) as reporter, the 1033-asi promoter was studied for spatial, temporal and hormonal control of gene expression. The 1033-asi promoter and its deletions direct transient gfp expression in the pericarp and at low levels in mature aleurone cells, and this expression is not regulated by ABA or GA. In transgenic barley plants, the 1033-asi promoter directed tissue-specific expression of the gfp gene in developing grain and germinating grain but not in roots or leaves. In developing grain, expression of gfp was observed specifically in the pericarp, the vascular tissue, the nucellar projection cells and the endosperm transfer cells and the hormones ABA or GA did not regulate this expression. In mature germinating grain gfp expression was observed in the embryo but not in aleurone or starchy endosperm. However, GA induced gfp expression in the aleurone of mature imbibed seeds from which the embryo had been removed. Expression in maternal rather than endosperm tissues of the grain suggests that earlier widespread assumptions that the protein is expressed largely in the endosperm may have been largely based on analysis of mixed grain tissues. This novel pattern of expression suggests that both activities of the protein may be primarily involved in seed defence in the peripheral tissues of the seed.

3' Flanking Region↗