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Soil bacterial diversity responses to root colonization by an ectomycorrhizal fungus are not root-growth-dependent.

The hypothesis tested in this present study was that the ectomycorrhizosphere effect on the bacterial community was not root-growth-dependent. The impacts of ectomycorrhizal infection (Pisolithus albus COI007) and a chemical fertilization to reproduce the fungal effect on root growth were examined on (1) the structure of bacterial community and (2) fluorescent pseudomonad and actinomycete populations in the mycorrhizosphere of Acacia auriculiformis using both culture-independent and culture-dependent methods. A. auriculiformis plants were grown in disinfested soil in pots with or without addition of the ectomycorrhizal fungus or N/P/K fertilization (to reproduce the fungal effect on root growth) for 4 months and then transferred to 20-L pots filled with nondisinfested sandy soil. The fungal and fertilizer applications significantly improved the plant growth after 4-month culture in the disinfested soil. In the nondisinfested cultural substrate, these positive effects on plant growth were maintained. The total soil microbiota was significantly different within the treatments as revealed from DNA analysis [denaturing gradient gel electrophoresis (DGGE)]. The structure of fluorescent pseudomonad populations was also affected by fungal and fertilizer applications. In contrast, no qualitative effect was observed for the actinomycete communities within each treatment, but fungal inoculation significantly decreased the number of actinomycetes compared to the fertilizer application treatment. These results show that the mycorrhizosphere effect is not root-growth-dependent but is mainly due to the presence of the ectomycorrhizal fungus and more particularly to the extramatrical mycelium.

Acacia↗

Root cooperation in a clonal plant: connected strawberries segregate roots.

The ability to selectively avoid competition with members of the same clone should be highly advantageous but has not been demonstrated in plants. We found that physical connection between plants in a clone of the wild strawberry Fragaria chiloensis induced them to segregate their roots, significantly increasing clonal performance. Such increase in performance was not found when plants were grown in containers that artificially divided their rooting zones. There was no effect of connection in a different clone of F. chiloensis with a lower degree of carbon transport between connected plants, suggesting that the mechanism for root segregation depended upon transport of a signal through the strawberry runners. We suggest that clonal integration allows some clones to coordinate below-ground resource foraging with other clone members, thus exhibiting a type of root cooperation.

Biomass↗

Formation of structures resembling ericoid mycorrhizas by the root endophytic fungus Heteroconium chaetospira within roots of Rhododendron obtusum var. kaempferi.

A resynthesis study was conducted to clarify the relationship between the root endophyte, Heteroconium chaetospira and the ericaceous plant, Rhododendron obtusum var. kaempferi. The host plant roots were recovered 2 months after inoculation, and the infection process and colonization pattern of the fungus were observed under a microscope. The hyphae of H. chaetospira developed structures resembling ericoid mycorrhizas, such as hyphal coils within the host epidermal cells. These structures were morphologically the same as previously reported ericoid mycorrhizal structures. The frequencies of hyphal coils within the epidermal cells of host roots ranged from 13 to 20%. H. chaetospira did not promote or reduce host plant growth. This is the first reported study that H. chaetospira is able to form structures resembling mycorrhizas within the roots of ericaceous plants.

Mitosporic Fungi↗

Root exudates of mycorrhizal tomato plants exhibit a different effect on microconidia germination of Fusarium oxysporum f. sp. lycopersici than root exudates from non-mycorrhizal tomato plants.

The effect of root exudates from mycorrhizal and non-mycorrhizal tomato plants on microconidia germination of the tomato pathogen Fusarium oxysporum f. sp. lycopersici was tested. Microconidia germination was enhanced in the presence of root exudates from mycorrhizal tomato plants. The more tomato plants were colonized by the arbuscular mycorrhizal fungus Glomus mosseae, the more microconidia germination was increased, indicating that alterations of the exudation pattern depended on the degree of root AM colonization. Moreover, alterations of the exudation pattern of mycorrhizal plants are not only local, but also systemic. Testing the exudates from plants with a high and a low P level revealed that the alterations of the root exudates from mycorrhizal plants, resulting in a changed effect on microconidia germination, are not due to an improved P status of mycorrhizal plants.

Fusarium↗

Functional and morphological changes of lumbar nerve roots induced by mechanical compression or the nucleus pulposus in contact with the root: analysis of fiber size-dependent vulnerability in rabbits.

The variation in symptoms of spinal nerve root damage may be caused by the difference of the size of damaged nerve fiber or difference between the mechanical influence and some chemical factors. We studied the relative vulnerability of small versus large myelinated fibers to a focal compression and/or an application of nucleus pulposus. We prepared the mechanical compression model by clipping the nerve root and the nucleus pulposus model by applying autologous nucleus pulposus on the nerve root in a rabbit and evaluated nerve root damage with respect to its fiber diameter. Nerve conduction velocity (NCV) of large myelinated nerve fiber was reduced significantly in every group compared with a sham operation group (sham) after 1 day in compression, but in the nucleus pulposus group (NP) the velocity was reduced significantly compared with sham only after 7 days. Histologic examination revealed that the number of damaged large fibers increased significantly in the compression group compared with sham after 3 days, but there was no difference in NP. NCV of small myelinated nerve fibers was reduced significantly in both the compression and NP groups compared with sham after 7 days. Histologic study showed the number of damaged small fibers increased significantly in the compression group compared with sham after 7 days. However, in the NP group the number of damaged fibers did not increase compared with sham. In conclusion, large myelinated nerve fiber was damaged earlier than small myelinated nerve fiber by compression, while nerve fiber damage caused by only the nucleus pulposus had no relation to nerve fiber size.

Action Potentials↗

Hairy roots induced by Agrobacterium rhizogenes and production of regenerative plants in hairy root cultures in maize.

Hairy roots of maize were induced by infecting 15-d calli with Agrobacterium rhizogenes. The hairy roots cultured in hormone-free media showed the vigorous growth and typical hairy root features. The regenerated plants were produced from hairy roots in MS media supplemented with 1.6 mg/L ZT and 0.4 mg/L NAA. The PCR-Southern hybridization demonstrated that T-DNA had been integrated into the chromosome of regenerated plants.

Blotting, Southern↗

Regional distribution of substance P in the spinal cord and nerve roots of the cat and the effect of dorsal root section.

Chemical properties of substance P in the spinal cord and dorsal roots of the cat were examined by gel chromatography and paper electrophoresis. The results suggest that the substance is identical with the undecapeptide, hypothalamic substance P, recently isolated from bovine hypothalamus. Distribution of substance P in the cat spinal cord (L5-S1) was investigated. Substance P was highly concentrated in the dorsal horn, where the highest level was found in the dorsal part. After the unilateral ligation and/or section of the dorsal roots, the level of substance P in the dorsal horn, particularly in its dorsal part, was markedly lowered. In the ligated and sectioned dorsal root, substance P was highly accumulated on the ganglion side, whereas its level was lowered on the central side of the ligature. These results suggest that hypothalamic substance P synthesized in the spinal ganglia is transported in the dorsal root toward their intraspinal axon terminals, where the substance is concentrated and serves as a neurotransmitter.

Animals↗

Dorsal root ganglion neurons with central processes in both dorsal and ventral roots in rats.

Axonal transport of fluorescent dyes, Diamidino yellow dihydrochloride (DY) and Fast blue (FB), applied to the cut distal ends of dorsal and ventral roots, respectively, was studied in order to determine whether any dorsal root ganglion (DRG) neurons have processes in both dorsal and ventral roots. A total of 359 DRG neurons are double labeled in 14 ganglia (L6 and S1) from 6 different animals, thus suggesting a possibility of many DRG neurons having multiple central processes. The somata of the double-labeled DRG neurons are small to medium in size with a mean diameter of 29 microns. These data are consistent with findings that the majority of ventral root afferent fibers are unmyelinated or small myelinated axons.

Amidines↗

Physical properties of root cementum: Part 9. Effect of systemic fluoride intake on root resorption in rats.

INTRODUCTION: Orthodontically induced inflammatory root resorption is a common complication in orthodontic treatment. Fluoride has been reported to have a beneficial effect against root resorption in dental traumatology. The effect of fluoride on orthodontically induced inflammatory root resorption has not been investigated. This study was undertaken to investigate the effect of fluoride on the incidence of root resorption. METHODS: Thirty-two female 8-week-old Wistar rats were separated into 4 groups. Two groups (6 rats per group) were controls; they did not undergo orthodontic tooth movement. The other 2 groups (10 rats per group) had orthodontic tooth movement consisting of activated 100-g closing nickel-titanium coils (NiTi 10-000-06, GAC International, Bohemia, NY) connecting the mandibular first molar to the incisors. Fluoridated water (100 ppm) was given ad libitum to 1 control and 1 experimental group. The other 2 groups received deionized water. After 2 weeks, the animals were killed, and the samples were harvested. Resorption craters were scanned with a Micro CT (SkyScan 1072, Aartselaar, Belgium). Software analysis of the scanned samples provided a volumetric measurement of the resorption craters on the mandibular molar cementum surface. RESULTS: Resorption sites were found in the control samples, especially on the distal surfaces; this could be attributed to normal physiological tooth drift. Resorption sites were significantly (P <.05) increased in the groups receiving orthodontic tooth movement. CONCLUSIONS: Fluoride reduces the size of resorption craters, but the effect is variable and not statistically significant (P >.05).

Administration, Oral↗

Production and metabolism of indole acetic acid in roots and root nodules of Phaseolus mungo.

The mature root nodules of Phaseolus mungo (L.), a leguminous pulse, contain higher amount of indole acetic acid (IAA) than non-nodulated roots. The tryptophan pool present in the mature nodule and young roots might serve as a precursor for the IAA production. Presence of IAA metabolising enzymes - IAA oxidase and peroxidase - indicate the metabolism of IAA in the nodules and roots. In culture, the symbiont, isolated from the nodules, produced a high amount of IAA, when tryptophan was supplied in the medium as a precursor. The symbiont preferred l-isomer over the dl- or d-isomer of tryptophan for IAA production. The important physiological implication of the IAA production in the legume-Rhizobium symbiosis is discussed.

Indoleacetic Acids↗

Flavonoids from shoots, roots and roots exudates of Brassica alba.

Analysis of extracts obtained from shoots, roots and exudates of Brassica alba revealed the presence of 3,5,6,7,8-pentahydroxy-4'-methoxy flavone in shoots, as well as 2',3',4',5',6'-pentahydroxy chalcone and 3,5,6,7,8-pentahydroxy flavone in roots and exudates. Apigenin was also found in the shoots and roots, but not in the root exudates.

Chalcones↗

Effects of ultrasonic root end preparation on resected root surfaces: SEM evaluation.

OBJECTIVE: The purpose of this study was to investigate the in vitro effect of ultrasonic retrotips on root end surfaces. STUDY DESIGN: Root end resection was performed on 45 single-root teeth endodontically treated after extraction. Setting the ultrasonic device at full power, a retrograde cavity was made by a stainless steel tip in 9 specimens (SS-FP). In another 9 samples a diamond tip was used (D-FP). Setting the intensity of the ultrasonic device at half power, 9 specimens were treated using stainless steel tips (SS-HP) and 9 using diamond tip (D-HP). Nine teeth were only apically resected and used as controls. Histologic serial sections were examined by scanning electron microsope to assess the number of root-face cracking, the marginal quality, and the crack type. RESULTS: No significant difference between diamond and stainless steel groups was found at a given power setting. Significant differences were found between SS-FP and SS-HP group for both the number of cracks and the marginal quality.

Adolescent↗

Bladder compliance after posterior sacral root rhizotomies and anterior sacral root stimulation.

To evaluate the effects of central detrusor denervation on bladder compliance, we studied 27 patients with complete suprasacral spinal cord injury in whom intradural posterior sacral root rhizotomies from S2 to S5 in combination with implantation of an intradural Finetech-Brindley bladder stimulator were performed. All patients initially presented with detrusor hyperreflexia. A majority of these patients had a decreased bladder compliance 5 days postoperatively followed by a rapid increase in bladder compliance thereafter. All patients showed persistent detrusor areflexia after long-term followup. In 2 patients incomplete posterior sacral rhizotomies appeared to be performed. These patients had low bladder compliance, so that secondary posterior sacral root rhizotomies at the level of the conus medullaris were done. Intradural rhizotomies of all posterior sacral root components from S2 to S5 in combination with implantation of an anterior sacral root stimulator is a safe and effective procedure in spinal cord injury patients.

Adolescent↗

A novel root-specific gene, MIC-3, with increased expression in nematode-resistant cotton (Gossypium hirsutum L.) after root-knot nematode infection.

A full-length cDNA, MIC-3, has been identified from a lambda ZAPII cDNA library constructed from the mRNA of nematode-resistant cotton (Gossypium hirsutum L.) roots after infection with root-knot nematode (Meloidogyne incognita). The putative open reading frame of MIC-3 encoded a protein of 141 amino acids with a calculated molecular mass of 15.3 kDa. Seven alternative polyadenylation sites have been identified for the MIC-3 transcripts, and the major transcripts are the longest ones. The MIC-3 gene contains a single intron within its coding region and belongs to a novel, multi-gene family containing up to six members. Expression of MIC-3 is root localized and specifically enhanced in the nematode induced, immature galls of resistant cotton line M-249, suggesting that MIC-3 may play a critical role in the resistance response to root-knot nematode.

Adhesins, Bacterial↗

Seventh cervical nerve root transfer from the contralateral healthy side for treatment of brachial plexus root avulsion.

Cervical root nerve transfer from the contralateral side has been used for the treatment of brachial plexus root avulsion in 49 patients. Resection of C7 root from the healthy side has produced no long-term symptoms or signs. Nine patients with ten recipient nerves have been followed up for more than two years and seven have obtained a functional recovery. This operation offers a new approach for the treatment of brachial plexus root avulsion.

Adolescent↗

Fatigue root fracture: a spontaneous root fracture in non-endodontically treated teeth.

A series of 46 cases of root fracture with four different patterns occurring in 51 non-endodontically treated teeth were studied. All of the patients had chewing habits which induced a unique root fracture. The results of this study suggest an additional cause of root fracture that has not been described previously. Here, the new term 'fatigue root fracture' is used to describe a fracture that results from an excessive, repetitive, heavy masticatory stress applied to a tooth. The majority (80%) of cases of this kind of fracture are vertical and occur mainly (96%) in persons over the age of 40. In addition, all the teeth affected were posterior teeth, and the majority (51%) were mandibular first molars.

Adult↗

Neuromodulation through sacral nerve roots 2 to 4 with a Finetech-Brindley sacral posterior and anterior root stimulator.

STUDY DESIGN: Investigation of five patients receiving an implant, using laboratory cystometry and self-catheterisation at home. OBJECTIVES: To use the established Finetech-Brindley sacral root stimulator to increase bladder capacity by neuromodulation, eliminating the need for posterior rhizotomy, as well as achieving bladder emptying by neurostimulation. SETTING: Spinal Injuries Unit, Royal National Orthopaedic Hospital, Stanmore, Middlesex, UK. METHODS: Five patients underwent implantation of a Finetech-Brindley stimulator without rhizotomy of the posterior roots. This was either a two channel extradural device (four cases) or a three channel intrathecal device (one case). In each patient, the implant was configured as a Sacral Posterior and Anterior Root Stimulator (SPARS). Postoperatively, repeated provocations using rapid instillation of 60 ml saline were used to determine the relative thresholds for neuromodulation using each channel. The effect of continuous neuromodulation was examined in the laboratory using slow fill cystometrograms, and conditional stimulation was also studied (neuromodulation for 1 min to suppress hyperreflexic contractions as they occurred). In one patient, neuromodulation was applied continuously at home, and volumes at self catheterisation recorded in a diary. RESULTS: Reflex erections were preserved in each patient. In three patients, detrusor hyperreflexia persisted postoperatively and neuromodulation via the implant was studied. In these three patients, the configuration was: S2 mixed roots bilaterally (channel B), and S34 bilaterally (channel A). Both channels could be used to suppress provoked hyperreflexic contractions, with the S2 channel effective at a shorter pulse width than S34 in a majority of cases. Continuous stimulation more than doubled bladder capacity in two out of three patients during slow fill cystometry. Conditional stimulation was highly effective. In the one patient who used continuous stimulation at home, bladder capacity was more than doubled and the effect was comparable with anticholinergic medication. Bladder pressures >70 cm water could be achieved with intense stimulation in three patients, but detrusor-external urethral sphincter dyssynergia (DSD) prevented complete emptying. CONCLUSIONS: Neuromodulation via a SPARS was effective and may replace the need for posterior rhizotomy. However, persisting DSD may prevent complete bladder emptying and warrants further investigation.

Adult↗