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.

SourceResearch connectionFrom yearThrough year

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

At least 1,801 records · Page 100Linked to original sources

PubMed2003

Homeobox gene expression in adult dorsal root ganglia during sciatic nerve regeneration: is regeneration a recapitulation of development?

After damage of the sciatic nerve, a regeneration process is initiated. Neurons in the dorsal root ganglion regrow their axons and functional connections. The molecular mechanisms of this neuronal regenerative process have remained elusive, but a relationship with developmental processes has been conceived. This chapter discusses the applicability of the developmental hypothesis of regeneration to the dorsal root ganglion; this hypothesis states that regeneration of dorsal root ganglion neurons is a recapitulation of development. We present data on changes in gene expression upon sciatic nerve damage, and the expression and function of homeobox genes. This class of transcription factors plays a role in neuronal development. Based on these data, it is concluded that the hypothesis does not hold for dorsal root ganglion neurons, and that regeneration-specific mechanisms exist. Cytokines and the associated Jak/STAT (janus kinase/signal transducer and activator of transcription) signal transduction pathway emerge as constituents of a regeneration-specific mechanism. This mechanism may be the basis of pharmacological strategies to stimulate regeneration.

Animals↗

PubMed1996

New Zealand health care financing 'reforms' perceived ideological context.

Health sector financing reforms that have been ongoing over the last decade in most developed countries are rooted in philosophical terms in the ideology of economic rationalism. The ideology suggests that it is possible to artificially create markets for activities in contexts where markets do not develop naturally, and that the creation of these artificial markets leads to resource allocations that are both more efficient and more equitable than historical arrangements. The application of the ideology to New Zealand's health sector has generated some benefit--for example, a more rational approach to influencing the decisions of self-interest health care providers; but it has also generated some costs--for example, on ideological grounds it has brought into question the non-market rationales for maintaining a national health service system.

Financing, Government↗

PubMed2002

Closing diastemas and creating artificial gingiva with polymer ceramics.

A 40-year-old male patient elected orthodontic correction of his crowded anterior teeth, leaving multiple root exposures and spacing in the papilla areas. Connective tissue surgery did not satisfy the patient's expectations and led him to seek alternative treatments. An innovative technique was developed to achieve root coverage and fill-in spaces in the papilla areas. This noninvasive technique used a polymer ceramic material that was bonded to the crown and root surface of the individual teeth. The veneer restorations were inserted on the teeth as a solid unit, then separated into individual units. Clinically, the hygiene, which has been monitored since the placement of the restorations 24 months ago, has been satisfactory. This case illustrates an attenuation of a previously described noninvasive laboratory technique to close spaces between teeth. This conservative method can be used to cover denuded root surfaces that may exhibit sensitivity. Although the treatment has been successful for the short-term, the results are promising and deserve further case-controlled clinical assessment.

Adult↗

PubMed2006

The hpa1 mutant of Arabidopsis reveals a crucial role of histidine homeostasis in root meristem maintenance.

Histidine (His) is an essential ingredient for protein synthesis and is required by all living organisms. In higher plants, although there is considerable evidence that His is essential for plant growth and survival, there is very little information as to whether it plays any specific role in plant development. Here, we present evidence for such a role of this amino acid in root development in Arabidopsis (Arabidopsis thaliana) from the characterization of a novel Arabidopsis mutant, hpa1, which has a very short root system and carries a mutation in one of the two Arabidopsis histidinol-phosphate aminotransferase (HPA) genes, AtHPA1. We have established that AtHPA1 encodes a functional HPA and that its complete knockout is embryo lethal. Biochemical analysis shows that the mutation in hpa1 only resulted in a 30% reduction in free His content and had no significant impact on the total His content. It did not cause any known symptoms of His starvation. However, the mutant displayed a specific developmental defect in root meristem maintenance and was unable to sustain primary root growth 2 d after germination. We have demonstrated that the root meristem failure in the mutant is tightly linked to the reduction in free His content and could be rescued by either exogenous His supplementation or AtHPA1 overexpression. Our results therefore reveal an important role of His homeostasis in plant development.

Amino Acid Sequence↗

PubMed2000

Expression of alpha-expansin genes in young seedlings of rice (Oryza sativa L.).

Rice is the only cereal in which germination and coleoptile elongation occur in hypoxia or anoxia. Little is known of the molecular basis directly underlying coleoptile cell extension. In this paper, we describe the expression of alpha-expansin genes in embryos during seed development and young seedlings grown under various oxygen concentrations. The genes Os-EXP2 and Os-EXP1 were predominantly expressed in the developing seeds, mainly in newly developed leaves, coleoptiles, and seminal roots. These expansins expressed in the developing seeds may give cells the potential to expand after seed imbibition begins. In coleoptiles, Os-EXP4 and Os-EXP2 mRNAs were greatly induced by submergence, while they were weakly detected in aerobic or anoxic conditions. Under submerged soil conditions, the signals hybridized with probes Os-EXP4 and Os-EXP2 in coleoptiles were strongest when coleoptiles elongated in the water layer. These data show that expansin gene expression is highly correlated with coleoptile elongation in response to oxygen concentrations. The Os-EXP4 gene was also expressed in leaves, mesocotyls, and coleorhizas of young seedlings. The growth of these tissues was also correlated with the presence of expansins. Therefore, the evidence derived from this study clearly demonstrates that expansins are indispensable for the growing tissues of rice seedlings.

Gene Expression Regulation, Developmental↗

PubMed1997

Dental calculus: recent insights into occurrence, formation, prevention, removal and oral health effects of supragingival and subgingival deposits.

Dental calculus, both supra- and subgingival occurs in the majority of adults worldwide. Dental calculus is calcified dental plaque, composed primarily of calcium phosphate mineral salts deposited between and within remnants of formerly viable microorganisms. A viable dental plaque covers mineralized calculus deposits. Levels of calculus and location of formation are population specific and are affected by oral hygiene habits, access to professional care, diet, age, ethnic origin, time since last dental cleaning, systemic disease and the use of prescription medications. In populations that practice regular oral hygiene and with access to regular professional care, supragingival dental calculus formation is restricted to tooth surfaces adjacent to the salivary ducts. Levels of supragingival calculus in these populations is minor and the calculus has little if any impact on oral-health. Subgingival calculus formation in these populations occurs coincident with periodontal disease (although the calculus itself appears to have little impact on attachment loss), the latter being correlated with dental plaque. In populations that do not practice regular hygiene and that do not have access to professional care, supragingival calculus occurs throughout the dentition and the extent of calculus formation can be extreme. In these populations, supragingival calculus is associated with the promotion of gingival recession. Subgingival calculus, in "low hygiene" populations, is extensive and is directly correlated with enhanced periodontal attachment loss. Despite extensive research, a complete understanding of the etiologic significance of subgingival calculus to periodontal disease remains elusive, due to inability to clearly differentiate effects of calculus versus "plaque on calculus". As a result, we are not entirely sure whether subgingival calculus is the cause or result of periodontal inflammation. Research suggests that subgingival calculus, at a minimum, may expand the radius of plaque induced periodontal injury. Removal of subgingival plaque and calculus remains the cornerstone of periodontal therapy. Calculus formation is the result of petrification of dental plaque biofilm, with mineral ions provided by bathing saliva or crevicular fluids. Supragingival calculus formation can be controlled by chemical mineralization inhibitors, applied in toothpastes or mouthrinses. These agents act to delay plaque calcification, keeping deposits in an amorphous non-hardened state to facilitate removal with regular hygiene. Clinical efficacy for these agents is typically assessed as the reduction in tartar area coverage on the teeth between dental cleaning. Research shows that topically applied mineralization inhibitors can also influence adhesion and hardness of calculus deposits on the tooth surface, facilitating removal. Future research in calculus may include the development of improved supragingival tartar control formulations, the development of treatments for the prevention of subgingival calculus formation, the development of improved methods for root detoxification and debridement and the development and application of sensitive diagnostic methods to assess subgingival debridement efficacy.

Adult↗

PubMedDate not supplied

Supernumerary roots.

Supernumerary roots are one of the development anomalies pertaining to the tooth root morphology. It is generally well known that the deciduous and permanent anterior teeth have a single root. Maxillary molars have three roots and mandibular molars have two roots. Pertaining to the premolars, except for the maxillary first premolars all other premolars have a single roots. These supernumerary roots may be due to the disturbances of the Hertwig's epithelial root sheath forming the root. Cases have been reported where in both the deciduous and permanent dentition exhibiting supernumerary roots. Here with we are presenting cases of supernumerary roots in permanent teeth involving maxillary third molars, mandibular first, second molars and mandibular second premolars.

Adolescent↗

PubMed1979

The U.S. hospice movement: issues in development.

A grass-roots hospice care movement is underway in the United States modeled after recently popularized British hospice programs. Hospice care is intended to help the terminally ill maintain a personally acceptable quality of life until death. Attention should be given to ensuring the future viability of this service option by allowing for experimentation with and adaptation of existing models, and by integrating it with the overall health care system. Issues to be considered in integrating hospice care include utilization of existing resources, regional planning, standards and licensure, and reimbursement opportunities. Although hospice care may not have an immediate cost savings impact on the health care system, it could develop this capacity in the future. Such impact would not only assure a stable financial base for hospice care but would also affect bed use generally. Continuing dialogue among providers, consumers, and policy makers of various backgrounds is necessary to the effective and appropriate development of hospice care in the U.S.

Health Resources↗

PubMed1997

Serial gadolinium-enhanced MR imaging after lumbar disc resection: observation of the affected root.

A prospective study was undertaken to clarify the relationship between postoperative morphological/pathological changes in the affected root and the clinical developments after disc resection. Gadolinium-enhanced magnetic resonance (MR) imaging was performed at 1 week, 5 weeks, 3 months, and 6 months after surgery for 28 patients of 34 consecutive patients who underwent single-level disc resection. Enhancement/thickening of the affected root was found to be 100%/89% at 1 week, 50%/57% at 3 months, and 32%/37% at 6 months after surgery. Patients with root enhancement and thickening at 3 and 6 months after surgery had less clinical improvement than patients without it. There was consistent correlation between postoperative clinical developments and nerve root enhancement/thickening in enhanced MR imaging. To use enhanced MR imaging as an evaluation tool after disc surgery might increase the diagnostic accuracy and reduce failed back surgery syndrome.

Adolescent↗

PubMed2005

Microcystin-RR uptake and its effects on the growth of submerged macrophyte Vallisneria natans (lour.) hara.

Microcystins are hepatotoxins produced by many species of several cyanobacterial genera. Their toxic effects on animals and some terrestrial higher plants have been well studied, but their potential effects on the development of aquatic plant seedlings are not well known, and their uptake by aquatic plants is seldom reported. In our research the seeds and seedlings of the submerged macrophyte Vallisneria natans were exposed to different concentrations of microcystin-RR, which was purified with high-performance liquid chromatography (HPLC). The results indicated that microcystin-RR could accumulate differentially in the roots and leaves of V. natans seedlings. Toxin accumulation in the roots and leaves was time- and dose-dependent, with higher uptake detected in the roots. Growth and development detection revealed that V. natans was relatively insensitive to microcystin-RR at concentrations ranging from 0.0001 to 0.01 mg/L. However, when the toxin concentration was more than 0.01 mg/L, both the fresh weight and the longest leaf length of seedlings were significantly reduced after a 30-day treatment. The root and leaf numbers were significantly decreased when 10 mg/L of toxin was used. These results suggest that microcystin-RR can be taken up by V. natans, which subsequently will retard its development.

Enzyme Inhibitors↗

PubMed1983

Circumstances favoring jaw tumors in Burkitt's lymphoma.

In Burkitt's lymphoma, dental structures may provide the route for Epstein-Barr virus (EBV) in saliva to penetrate the jaws, thereby promoting tumor formation. In children, EBV could enter tooth sockets exposed following deciduous tooth loss and thereby contact jaw marrow lymphocytes stimulating neoplastic transformation. Marrow contact by EBV probably also occurs through carious teeth. Jaw tumors are rare in adults because their jaw marrow is no longer hematopoietic and so lacks the lymphoid substrate for the virus. In adults, jaw marrow lymphocytosis, as accompanies infectious mononucleosis and perhaps malaria, or which could develop around the roots of carious teeth having chronic periapical infection, could provide the substrate for EBV. EBV could then contact the jaw marrow lymphocytes when teeth are extracted and so favor jaw tumor development. Therefore, prevention of dental caries might reduce jaw tumor prevalence in Burkitt's lymphoma except among children ages 6-13 whose jaw marrow would unavoidably become infected by salivary EBV when the latter is present at the time of deciduous tooth loss.

Burkitt Lymphoma↗

PubMed1999

Effects of copper exposure in tissue cultured Vitis vinifera.

The present study determined the effects of copper treatment on some biochemical parameters in a closed system. Sauvignon grapevines were cultured in agar and exposed to copper levels ranging from 0.07 to 10 microg Cu/g medium. Chlorophylls, carotenoids, lipids, sucrose, soluble sugars, starch, cellulose, and minerals in root, leaves, and sap were determined. Copper levels over 5 microg Cu/g inhibit root and plantlet development. Copper-exposed plants have higher levels of chlorophylls and carotenoids as well as total lipids. Soluble sugars decrease without changes in starch or sucrose. Copper concentration increases dramatically in roots and leaves. Iron concentrations are lower in leaves, although they increase in roots, with respect to control plants. Sap flow and translocation of essential elements are reduced. Reduction of K translocation can be related to limited use of water by the plant and, thus, reduction in growth and physiological activity.

Carbohydrates↗

PubMed1989

Adventitious roots, leaf abscission and nutrient status of flooded Gmelina and Tectona seedlings.

When flooded, seedlings of Gmelina arborea Roxb. produced more adventitious roots, had lower foliar Mn concentrations and lost fewer leaves than seedlings of Tectona grandis L.f. Severing the adventitious roots produced by flooded Gmelina seedlings increased leaf Mn concentration and leaf abscission and reduced whole-plant dry matter production. Flooded Gmelina cuttings, which do not produce adventitious roots, abscised few leaves until foliar concentrations of Mn and Fe had risen substantially above those of unflooded cuttings, at which time most leaves were shed. The results indicate that the development of adventitious roots in flooded seedlings of Gmelina suppressed uptake of Mn thereby minimizing leaf abscission.

Journal Article↗

PubMed2003

Isolation and characterization of a rice WUSCHEL-type homeobox gene that is specifically expressed in the central cells of a quiescent center in the root apical meristem.

The Arabidopsis WUSCHEL (WUS) protein, which plays an important role in the specification of the stem cells in the shoot apical meristem (SAM), contains an 'atypical' homeodomain (HD) with extra residues in its loop and turn regions. We speculated that a WUS-type atypical HD protein might also be involved in the specification and maintenance of the root apical meristem (RAM) stem cells of rice. To investigate this possibility, we isolated and characterized a rice WUS-type homeobox gene designated quiescent-center-specific homeobox (QHB) gene. Using transformants carrying the QHB promoter-GUS and in situ hybridization, we found that QHB was specifically expressed in the central cells of a quiescent center (QC) of the root. During embryogenesis and crown root formation, QHB expression was observed prior to the morphological differentiation of the root. However, we detected different QHB expression patterns in the process of the RAM development, specifically between radicle and crown root formation, suggesting that the cell-fate determination of the QC may be controlled by different mechanisms. We also produced transformants that overexpress QHB or Arabidopsis WUS. These transformants did not form crown roots, but developed multiple shoots from ectopic SAMs with malformed leaves. On the basis of these observations, we propose that the WUS-type homeobox gene is involved in the specification and maintenance of the stem cells (QC cells) in the RAM, by a mechanism similar to that for WUS in the SAM.

Amino Acid Sequence↗

PubMedDate not supplied

Neoaortic root dilation associated with left coronary artery stenosis following arterial switch procedure.

We describe a patient who was diagnosed with d-transposition of the great arteries, with intact ventricular septum, who underwent arterial switch procedure on day 5 of life. Over the subsequent years, he developed progressive neoaortic root dilation with a Z score of up to 7.2. At 5 years of age, he presented with myocardial infarction. Cardiac catheterization demonstrated a markedly dilated aortic root with kinking and stenosis of the left main coronary artery into the left anterior descending coronary artery. He underwent emergency left internal mammary artery bypass grafting to the left anterior descending coronary artery. Although he required left ventricular assist device (LVAD) support in the early post-operative period, he recovered with a left ventricular ejection fraction of 52% on the most recent follow-up.

Aorta, Thoracic↗

PubMed2006

The Arabidopsis major intrinsic protein NIP5;1 is essential for efficient boron uptake and plant development under boron limitation.

Boron (B) is essential in plants but often present at low concentrations in the environment. To investigate how plants survive under conditions of B limitation, we conducted a transcriptome analysis and identified NIP5;1, a member of the major intrinsic protein family, as a gene upregulated in B-deficient roots of Arabidopsis thaliana. Promoter-beta-glucuronidase fusions indicated that NIP5;1 is strongly upregulated in the root elongation zone and the root hair zone under B limitation, and green fluorescent protein-tagged NIP5;1 proteins localized to the plasma membrane. Expression in Xenopus laevis oocytes demonstrated that NIP5;1 facilitated the transport of boric acid in addition to water. Importantly, two T-DNA insertion lines of NIP5;1 displayed lower boric acid uptake into roots, lower biomass production, and increased sensitivity of root and shoot development to B deficiency. These results identify NIP5;1 as a major plasma membrane boric acid channel crucial for the B uptake required for plant growth and development under B limitation.

Animals↗

PubMedDate not supplied

Accumulation of transcripts encoding a lipid transfer-like protein during deformation of nodulation-competent Vigna unguiculata root hairs.

A cDNA library was constructed from RNA of Vigna unguiculata root hairs harvested 1 day and 4 days after inoculation with Rhizobium sp. NGR234. A heterologous probe was used to identify a cDNA clone, the predicted 99-amino-acid sequence of which shares homology with a nonspecific lipid transfer protein (LTP) of Hordeum vulgare. Other characteristics, including an estimated molecular weight of 10.4 kD, an isoelectric point of 8.6, and a signal peptide with a hydrophobic region at the amino-terminal end, are shared by most LTPs. A transcript of 630 nt was found in all tissues tested, except nodules. Levels of mRNA increased in root hairs 24 hr after treatment with Rhizobium sp. NGR234, with different hormones, or with Nod factors. Amounts of transcripts were dependent on the concentration of Nod factors. Accumulation of transcripts during nodule development correlated with root hair deformation, the first visible step in the Rhizobium-legume symbiosis.

Amino Acid Sequence↗

PubMedDate not supplied

Chemical restrictions of roots in Ultisol subsoils lessened by long-term management.

Exchangeable Al in subsoils of Ultisols in the southeastern USA can restrict rooting depth. Downward movement of basic cations (Ca, Mg, and K), applied as lime and fertilizer, may diminish that restriction over time. Materials from the argillic horizon were collected from three paired sites, having managed (long-term cropping) and nonmanaged topsoils (Typic Paleudults and Hapludults). One managed site was cropped continuously for 15 yr while the others were cultivated for more than 30 yr. Concentrations of extractable cations and other nutrients from the paired sites were compared to determine the magnitude of change due to management. The ability of the subsoils to support plant growth was evaluated in a missing-nutrient greenhouse experiment with sorghum [Sorghum bicolor (L.) Moench]. Subsoils of managed sites had greater effective cation-exchange capacity (CEC) and base saturation than those of non-managed sites. While availabilities of Ca, Mg, and K in subsoils of nonmanaged sites were inadequate to support maximal plant growth, they were adequate in subsoils of managed sites. Compared with nonmanaged sites, KCl-exchangeable Al in subsoils of managed sites was 23% lower at the 15-yr location and 65 and 100% lower at the two other locations. In the absence of lime, sorghum growth was almost totally inhibited on nonmanaged subsoils amended with optimum nutrients. On the managed subsoils, where 100, 65, and 23% of the nonmanaged exchangeable Al had been neutralized by topsoil fertilization and liming, growth reductions under the same conditions were 0, 50, and 100%, respectively. Thus, relatively long-term management had improved these Ultisol subsoils for root growth and development.

Aluminum↗

Refine your search to explore more results.