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PubMed1993

Changes in nuclear 3,5,3'-triiodothyronine receptor expression in rat dorsal root ganglia and sciatic nerve during development: comparison with regeneration.

The action of the thyroid hormones on responsive cells in the peripheral nervous system requires the presence of nuclear triiodothyronine receptors (NT3R). These nuclear receptors, including both the alpha and beta subtypes of NT3R, were visualized by immunocytochemistry with the specific 2B3 monoclonal antibody. In the dorsal root ganglia (DRG) of rat embryos, NT3R immunoreactivity was first discretely revealed in a few neurons at embryonic day 14 (E14), then strongly expressed by all neurons at E17 and during the first postnatal week; all DRG neurons continued to possess clear NT3R immunostaining, which faded slightly with age. The peripheral glial cells in the DRG displayed a short-lived NT3R immunoreaction, starting at E17 and disappearing from the satellite and Schwann cells by postnatal days 3 and 7 respectively. In the developing sciatic nerve, Schwann cells also exhibited transient NT3R immunoreactivity restricted to a short period ranging from E17 to postnatal day 10; the NT3R immunostaining of the Schwann cells vanished proximodistally along the sciatic nerve, so that the Schwann cells rapidly became free of detectable NT3R immunostaining. However, after the transection or crushing of an adult sciatic nerve, the NT3R immunoreactivity reappeared in the Schwann cells adjacent to the lesion by 2 days, then along the distal segment in which the axons were degenerating, and finally disappeared by 45 days, when the regenerating axons were allowed to re-occupy the distal segment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Nodule-specific repression of yellow lupin protein R18.

It was found, using immunochemical techniques, that protein R18 presumably specifically repressed during development of lupin root nodules (Sikorski et al., 1989, Acta Biochim. Polon., 36, 63-72) is present in various tissues of this plant. Protein R18 was also detected in roots of four other legumes but was absent from the bacteroid-containing cells of root nodules. The data support our earlier view (Sikorski et al., op. cit.) that expression of protein R18 is regulated by the coupled mechanism of induction and repression of specific plant genes during development of lupin root nodule.

Fabaceae↗
PubMed2002

Structure and development of stomata on the primary root of Ceratonia siliqua L.

Stomata of various sizes are produced on the primary root of Ceratonia siliqua L. Most are generated during embryogenesis, prior to seed desiccation. They can be detected on the dry embryo in a wide zone just above the root tip. Initially, large stomata are formed. These have the ability to induce divisions of their neighbouring cells, creating particular cell patterns around them. Later, small perigenous stomata are generated. As the root grows following seed germination, the stomatal zone overlaps with that of the root hairs. Although root stomata of C. siliqua undergo a structural differentiation that seems almost identical to that of the elliptical stomata formed on leaves, they are unable to move and remain permanently open. Polarizing microscopy of fully differentiated stomata and young stomata at the stage of stomatal pore formation revealed deposition of radial cellulose microfibril systems on their periclinal walls. However, these systems were less developed than those on leaf stomata, a feature that might be responsible for their inactivity. Besides, plastids of the root guard cells (GCs) do not differentiate into chloroplasts but function solely as amyloplasts. Root stomata have a short life span. During rapid and intense root growth, GCs cannot keep pace with the elongation of their neighbouring rhizodermal cells. They therefore split in their mid-region, transversely to the stoma axis. The two parts of the transversely torn stoma are dragged apart and a large opening is formed on the root surface, just above the substomatal cavity. The root stomata, together with these openings, may facilitate increased gaseous exchange during respiration and/or an increased transfer of some nutrients and water in the rapidly growing primary root.

Cell Wall↗
PubMed1999

Antisense repression of vacuolar and cell wall invertase in transgenic carrot alters early plant development and sucrose partitioning.

To unravel the functions of cell wall and vacuolar invertases in carrot, we used an antisense technique to generate transgenic carrot plants with reduced enzyme activity. Phenotypic alterations appeared at very early stages of development; indeed, the morphology of cotyledon-stage embryos was markedly changed. At the stage at which control plantlets had two to three leaves and one primary root, shoots of transgenic plantlets did not separate into individual leaves but consisted of stunted, interconnected green structures. When transgenic plantlets were grown on media containing a mixture of sucrose, glucose, and fructose rather than sucrose alone, the malformation was alleviated, and plantlets looked normal. Plantlets from hexose-containing media produced mature plants when transferred to soil. Plants expressing antisense mRNA for cell wall invertase had a bushy appearance due to the development of extra leaves, which accumulated elevated levels of sucrose and starch. Simultaneously, tap root development was markedly reduced, and the resulting smaller organs contained lower levels of carbohydrates. Compared with control plants, the dry weight leaf-to-root ratio of cell wall invertase antisense plants was shifted from 1:3 to 17:1. Plants expressing antisense mRNA for vacuolar invertase also had more leaves than did control plants, but tap roots developed normally, although they were smaller, and the leaf-to-root ratio was 1.5:1. Again, the carbohydrate content of leaves was elevated, and that of roots was reduced. Our data suggest that acid invertases play an important role in early plant development, most likely via control of sugar composition and metabolic fluxes. Later in plant development, both isoenzymes seem to have important functions in sucrose partitioning.

Cell Wall↗
PubMed2000

Rnf4, a RING protein expressed in the developing nervous and reproductive systems, interacts with Gscl, a gene within the DiGeorge critical region.

A yeast 2-hybrid screen was performed to identify possible transcriptional modulators interactive with goosecoid-like (gscl), a transcription factor with suppressive activity, expressed during early brain and gonad development. The screen resulted in the identification of a RING protein known as rnf4 or snrf. Gscl/rnf4 interactions were confirmed by affinity chromatography and by immunoprecipitation. Northern analysis confirmed earlier reports of ubiquitous rnf4 expression in adult tissues. Immunohistochemical analysis of mouse embryos revealed expression primarily in the developing nervous system, with strong expression in the dorsal root ganglia and developing gonads. In contrast to previous reports, both cytoplasmic and nuclear expression of rnf4 was documented. The results reported here confirm and extend earlier reports of rnf4 expression. They suggest for the first time, that in addition to acting as a modulator of transcriptional activity, rnf4 may function, as do other RING proteins, to promote the formation of intracytoplasmic complexes involved in shuttling information between the cytoplasm and the nucleus.

Animals↗
PubMed2004

Quantitative analysis of phytoestrogens in kudzu-root, soy and spiked serum samples by high-pressure liquid chromatography.

A sensitive and reliable HPLC method that allows simultaneous quantification of phytoestrogens extracted from kudzu-root and soy preparations, and serum samples has been developed. Kudzu-root and soy preparations were mixed with 5 microg flavone and 15 microg rutin (internal standards) and the phytoestrogens were extracted by using solid-phase (C18) extraction cartridges. Blank or spiked serum samples were extracted by using either C18 cartridges or trichloroacetic acid-methanol extraction. The extracts were analyzed by the HPLC equipped with a reverse-phase (250 x 4 mm, C18) column and UV, diode-array or MS detector. A linear gradient of acetic acid and acetonitrile provided excellent separation of glycoside and aglycone-phytoestrogens from kudzu root and soy preparations. The C18 cartridge extraction of serum yielded excellent recovery of both glycoside- and aglycone-phytoestrogens, while the trichloroacetic acid-methanol extraction yielded excellent recovery of glycoside but poor recovery of aglycone compounds. UV and MS detectors were suitable for phytoestrogen analysis in plant and serum samples, while the diode-array detector was suitable for generating the UV absorbance curve for phytoestrogens.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Two validated HPLC methods for the quantification of alizarin and other anthraquinones in Rubia tinctorum cultivars.

Direct and indirect HPLC-UV methods for the quantitative determination of anthraquinones in dried madder root have been developed, validated and compared. In the direct method, madder root was extracted twice with refluxing ethanol-water. This method allowed the determination of the two major native anthraquinone glycosides lucidin primeveroside and ruberythric acid. In the indirect extraction method, the anthraquinone glycosides were first converted into aglycones by endogenous enzymes and the aglycones were subsequently extracted with tetrahydrofuran-water and then analysed. In this case the anthraquinones alizarin, purpurin and nordamnacanthal may be determined. The content of nordamnacanthal is proportional to the amount of lucidin primeveroside originally present. The indirect extraction method is easier to apply. Different madder cultivars were screened for their anthraquinone content.

Anthraquinones↗
PubMed1995

Endocarditis with multiple intracardiac shunts: identification and repair.

An 8-year-old boy who suffered from Hirschsprung's disease had development of tricuspid valve endocarditis that progressed to aortic root abscess formation, development of a fistulous communication between aorta and right atrium, atrial and ventricular septal defects, and a left ventricle to right atrium defect. Several surgical procedures were required. Operation consisted initially of closure of the septal defects and aortic valve repair. This was followed by homograft replacement of the aortic valve for persistent infection, and further closure of a left ventricle to right atrium fistula.

Abscess↗
PubMed1999

Neuroendocrine dysplasia in mice lacking protein tyrosine phosphatase sigma.

Protein tyrosine phosphatase sigma (PTP-sigma, encoded by the Ptprs gene) is a member of the LAR subfamily of receptor-like protein tyrosine phosphatases that is highly expressed during mammalian embryonic development in the germinal cell layer lining the lateral ventricles of the developing brain, dorsal root ganglia, Rathke's pouch, olfactory epithelium, retina and developing lung and heart. On the basis of its expression and homology with the Drosophila melanogasterorthologues DPTP99 and DPTP100A (refs 5,6), which have roles in the targeting of axonal growth cones, we hypothesized that PTP-sigma may also have a modulating function in cell-cell interactions, as well as in axon guidance during mammalian embryogenesis. To investigate its function in vivo, we generated Ptprs-deficient mice. The resulting Ptprs-/-animals display retarded growth, increased neonatal mortality, hyposmia and hypofecundity. Anatomical and histological analyses showed a decrease in overall brain size with a severe depletion of luteinizing hormone-releasing hormone (LHRH)-immunoreactive cells in Ptprs-/- hypothalamus. Ptprs-/- mice have an enlarged intermediate pituitary lobe, but smaller anterior and posterior lobes. These results suggest that tyrosine phosphorylation-dependent signalling pathways regulated by PTP-sigma influence the proliferation and/or adhesiveness of various cell types in the developing hypothalamo-pituitary axis.

Animals↗
PubMed2003

Modelling cereal root systems for water and nitrogen capture: towards an economic optimum.

A quantitative model of wheat root systems is developed that links the size and distribution of the root system to the capture of water and nitrogen (which are assumed to be evenly distributed with depth) during grain filling, and allows estimates of the economic consequences of this capture to be assessed. A particular feature of the model is its use of summarizing concepts, and reliance on only the minimum number of parameters (each with a clear biological meaning). The model is then used to provide an economic sensitivity analysis of possible target characteristics for manipulating root systems. These characteristics were: root distribution with depth, proportional dry matter partitioning to roots, resource capture coefficients, shoot dry weight at anthesis, specific root weight and water use efficiency. From the current estimates of parameters it is concluded that a larger investment by the crop in fine roots at depth in the soil, and less proliferation of roots in surface layers, would improve yields by accessing extra resources. The economic return on investment in roots for water capture was twice that of the same amount invested for nitrogen capture.

Models, Theoretical↗
PubMed2002

Autoregulation of root nodule formation: signals of both symbiotic partners studied in a split-root system of Vicia sativa subsp. nigra.

Inhibition of root nodule formation on leguminous plants by already induced or existing root nodules is called autoregulation of root nodule formation (AUT). Optimal conditions for AUT were determined using a split-root technique newly developed for Vicia sativa subsp. nigra. Infection of a root A with nodulating Rhizobium leguminosarum bv. viciae bacteria systemically inhibited nodulation of a spatially separated root B inoculated 2 days later with the same bacteria. This treatment gives complete AUT (total absence of nodules on root B). Only partial AUT of root B was obtained by incubation of root A with mitogenic nodulation (Nod) factors or with a noninfective strain producing normal mitogenic Nod factors. Nonmitogenic Nod factors did not evoke AUT. We identified two systemic plant signals induced by Rhizobium bacteria. Signal 1 (at weak buffering) was correlated with sink formation in root A and induced acidification of B-root medium. This signal is induced by treatment of root A with (i) nodulating rhizobia, (ii) mitogenic Nod factors, (iii) nonmitogenic Nod factors, or (iv) the cytokinin zeatin. Signal 2 (at strong buffering) could only be evoked by treatment with nodulating rhizobia or with mitogenic Nod factors. Most probably, this signal represents the specific AUT signal. Induction of complete AUT appears to require actively dividing nodule cells in nodule primordia, nodule meristems, or both of root A.

Culture Media↗
PubMed1992

A Developmental Analysis of the Enolase Isozymes from Ricinus communis.

Enolase activity was measured in clarified homogenates of various tissues during the life cycle of the castor oil plant (Ricinus communis L. cv Baker 296). The proportions of total activity due to the plastid and cytosolic isozymes were determined after separation by ion-exchange chromatography. The contribution of the plastid isozyme varied from more than 30% of the total at the midpoint of endosperm development to less than 1% in mature leaves and roots. During endosperm development, enolase activity increased to a peak coincident with the maximum rate of storage lipid accumulation, then decreased to nearly undetectable levels in the mature seed. Plastid enolase protein, measured using an enzyme-linked immunosorbent assay, increased in parallel with the increase in activity but decreased less rapidly and was still easily detectable in mature seeds.

Journal Article↗
PubMed2005

Classification, reproducibility and prevalence of root proximity in periodontal patients.

AIM: The primary aim of this study is to define and classify root proximity. The secondary aim is to examine the reproducibility of the measurement tools, to study the prevalence per inter-dental area and to examine whether the distance from the cemento-enamel junction (CEJ) to the bone crest (BC) differs between sites with root proximity and their contra-lateral sites without root proximity. MATERIAL AND METHODS: In order to indicate the location of root proximity, a modification of the Shei ruler was developed, dividing the roots into three equal parts. A radiographic template was used to measure the distance between the roots, in this way determining the severity of the root proximity. The reproducibility of the measurement tool was tested, the prevalence was calculated and the distances CEJ-BC for root proximity sites and contra-lateral sites were recorded. RESULTS: A two-digit classification was obtained dividing the root into three locations [apical (A), between (B) and coronal (C)], with each location having the possibility of three different severities of root proximity. The described modification of the Shei ruler and the measurement tool for the severities can be considered as reproducible measurement tools. Root proximity was most prevalent in maxillary molars and between central and lateral incisors in the maxilla and mandible. There was no difference in CEJ-BC distance between the root proximity sites and their contra-lateral sites. CONCLUSION: We can conclude that a two-digit classification for root proximity was established. Root proximity in untreated periodontal patients has no influence on the distance CEJ-BC. However, the location of root proximity becomes important from the moment that periodontal disease has been established at that site. The severity of root proximity is important for choosing treatment options. There is a striking similarity between bone loss patterns and tooth loss and the location of inter-dental spaces where root proximity is most prevalent.

Adolescent↗
PubMed1984

Effects of relative humidity and root temperature on calcium concentration and tipburn development in lettuce.

Growth chamber studies were undertaken with a tipburn-sensitive cultivar of romaine lettuce (Lactuca sativa L. cv. Lobjoits Green Cos) grown under a photosynthetic photon flux density of 320 micromoles s-1 m-2 for 16 hours; light and dark temperatures were 26.0 degrees and 12.5 degrees C, respectively. As the relative humidity (RH) during the light period was decreased from 74% to 51%, growth was retarded, Ca concentration increased, and the onset of tipburn delayed. Decreasing RH during the dark period from 95% to 90% reduced growth and resulted in lower Ca concentrations and earlier tipburn development. Further decreases from 90% to 65% caused no additional change in growth or tipburn response. Root temperatures of 23.5 degrees, compared with 15.0 degrees, slightly increased Ca concentration but induced earlier tipburn development. Ca concentrations were increased and tipburn delayed by humidity conditions which provided large diurnal fluctuations in water potential in the plant and which encouraged root pressure flow during the dark period. Elevated root temperatures did not provide expected increases in Ca accumulation in young leaves.

Calcium↗
PubMed2004

[Mechanism of stomatal regulation by root sourced signaling and its agricultural signficance].

Under soil drought condition, root sourced signal abcisic acid (ABA) plays an important role in the long distance signaling process, and can be a measurement of soil water availability. ABA is also an effective stomatal closing agent, and acts to reduce transpiration and canopy water loss. This paper briefly introduced the physiological mechanism and theoretical model about the stomatal regulation by root sourced signaling, and indicated that the combination of this model with root water absorption model and stomatal conductance model could be more effective in depicting the response of plant to soil drying and atmospheric drought. In addition, some effective irrigation approaches, such as regulated deficit irrigation (RDI), partial root-zone drying (PRD) and controlled alternative irrigation (CAI) were profited from the mechanism of plant water use regulation by the root sourced signaling. These irrigation measures favored to reasonably distribute available soil water in root-zone. Root signaling system also played important role in regulating root growth and its development, retarding shoot growth to adjusting root shoot ratio, and optimizing assimilation allocation to favor to improve reproductive development. These processes hold substantial promise for enhancing crop water use efficiency.

Abscisic Acid↗
PubMed2005

Induction of a homeodomain-leucine zipper gene by auxin is inhibited by cytokinin in Arabidopsis roots.

Homeobox genes are essential regulators of the development of plants as well as other organisms. We chose eight putative Arabidopsis homeobox genes not previously characterized and examined their expression in response to treatment with auxin/cytokinin. One of them, ATHB53, was further studied because it was auxin-inducible and its induction was inhibited by cytokinin. Its full-length cDNA was cloned and found to encode a protein of the HD-Zip superfamily. Whole-mount in situ hybridization and RT-PCR showed that it was expressed in the root meristem, and auxin treatment increased its expression, especially in a region from 0.3 to 0.6mm from the root tip. These results suggest that ATHB53 plays a regulatory role in auxin/cytokinin signaling during root development.

Arabidopsis↗
PubMed2006

Drawing from Freirian empowerment methods to develop and use innovative learning maps: increasing enrollment of uninsured children on Detroit's eastside.

In 2001, virtually every child on Detroit's eastside was eligible for health coverage, yet approximately 3,000 children remained uninsured. The primary aim of the Eastside Access Partnership (EAP), a community-based participatory research collaboration, was to increase enrollment of uninsured children in state programs. To achieve this aim, one of the approaches that EAP is using is the innovative Learning Map titled Choosing the Healthy Path, which was developed in collaboration with Root Learning, Inc. Although Learning Maps were originally developed to assist corporations in implementing strategic change, their integration of visualization and interactive dialogue incorporates Freirian principles of empowerment education, making them a viable option for providing meaningful learning opportunities for community residents. This article presents the collaborative process involving the University of Michigan, local community-based organizations, community members, and Root Learning consultants to develop a visual map that enables community residents to understand and overcome the barriers that prevent them from obtaining health insurance for their children.

Adolescent↗
PubMed2004

The function of the superficial root mat in the biogeochemical cycles of nutrients in congolese eucalyptus plantations.

BACKGROUND AND AIMS: The importance of superficial root mats inside the forest floor for the nutrition of Amazonian rain forests has been extensively investigated. The present study was aimed at assessing the function of a root mat adherent to decomposing organic material observed in Eucalyptus plantations. METHODS: The development of the root mat was studied through micromorphological observations of thin litter sections, and the influence of soil microtopography and soil water repellency on root mat biomass was assessed in situ on an area of 5 m2. In addition, input-output budgets of nutrients within the forest floor were established from measurements of litterfall, dissolved nutrients in gravitational solutions, and forest floor nutrient contents. KEY FINDINGS: The amounts of nutrients released during litter decay in this ecosystem during the period of study were, on average, 46, 3, 4, 19 and 17 kg ha-1 year-1 for N, P, K, Ca and Mg, respectively. The simultaneous measurements of the chemical composition of throughfall solutions and leachates beneath the forest floor showed a very quick uptake of nutrients by the root mat during the decomposition processes. Indeed, the solutions did not become noticeably enriched in nutrients during their passage through the holorganic layer, despite large amounts of elements being released during litter decay. The root mat biomass decreased significantly during the dry season, and a preferential development in microdepressions at the soil surface was observed. A strong water repellency observed in these depressions might enhance the ability of the roots to take up water and nutrients during the dry periods. CONCLUSIONS: The root mat was active throughout the year to catch the flux of nutrients from the biodegradation of the forest floor, preventing the transfer of dissolved nutrients toward deeper soil horizons. This mechanism is involved in the successful adaptation of this Eucalyptus hybrid in areas covered by 'climacic' savannas in Congo.

Biodegradation, Environmental↗