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PubMed1984

Circulation, bone scans, and tetracycline labeling in microvascularized and vascular bundle implanted rib grafts.

The circulation in microvascularized rib grafts has been compared with that in conventional rib grafts and in those augmented by a direct vascular bundle implantation into the bone grafts. A new experimental model has been designed to correlate vascular perfusion, bone scan patterns, tetracycline labeling, and histological findings in these bone grafts. Posterior microvascularized rib grafts were found to have a circulatory pattern identical to that of the normal rib. Failed microvascularized rib grafts were revascularized more slowly than conventional rib grafts. Vascular bundles implanted into rib grafts remained patent and increased the rate of revascularization. The stripping or preservation of periosteum had no observable effects on the rate or pattern of conventional rib graft revascularization. The circulation in rib grafts was accurately reflected in technetium 99 bone scans, as was the patency of the anastomoses of microvascularized rib grafts and of implanted vascular bundles. In contrast, tetracycline labeling was repeatedly observed in avascular areas of bone grafts and, therefore, is not a reliable indicator of bone graft circulation.

Animals↗
PubMed2005

Metabolic profiling of laser microdissected vascular bundles of Arabidopsis thaliana.

BACKGROUND: Laser microdissection is a useful tool for collecting tissue-specific samples or even single cells from animal and plant tissue sections. This technique has been successfully employed to study cell type-specific expression at the RNA, and more recently also at the protein level. However, metabolites were not amenable to analysis after laser microdissection, due to the procedures routinely applied for sample preparation. Using standard tissue fixation and embedding protocols to prepare histological sections, metabolites are either efficiently extracted by dehydrating solvents, or washed out by embedding agents. RESULTS: In this study, we used cryosectioning as an alternative method that preserves sufficient cellular structure while minimizing metabolite loss by excluding any solute exchange steps. Using this pre-treatment procedure, Arabidopsis thaliana stem sections were prepared for laser microdissection of vascular bundles. Collected samples were subsequently analyzed by gas chromatography-time of flight mass spectrometry (GC-TOF MS) to obtain metabolite profiles. From 100 collected vascular bundles (approximately 5,000 cells), 68 metabolites could be identified. More than half of the identified metabolites could be shown to be enriched or depleted in vascular bundles as compared to the surrounding tissues. CONCLUSION: This study uses the example of vascular bundles to demonstrate for the first time that it is possible to analyze a comprehensive set of metabolites from laser microdissected samples at a tissue-specific level, given that a suitable sample preparation procedure is used.

Journal Article↗
PubMed2006

Structural changes in the vascular bundles of light-exposed and shaded spruce needles suffering from Mg deficiency and ozone pollution.

The correlation between structural changes of the vascular bundles and needle yellowing was examined for needles of damaged spruce (Picea abies (L.) Karst.) growing at a Mg-deficient and ozone polluted mountain site in the Central Black Forest (840m a.s.l.). In the previous year's sun-exposed needles, the following sequence of events was observed: (1) rapid needle yellowing, (2) hypertrophy and anomalous divisions of cambium cells, (3) phloem collapse, and, (4) production of atypical xylem tracheids. Under defined shade (reduction of the photosynthetically active photon flux density of the ambient light by 85-90%), the needles remained green, while the phloem collapsed completely within the first 6 weeks of shading; subsequently, a reversal of the collapse was observed. Under both light conditions, the content of Mg not bound to chlorophyll (Mg(free)) was in the range of 0.1 mg g(-1) needle dry matter, and hardly changed throughout the investigation period. After Mg fertilization, the Mg(free) level of the previous year's needles increased to 0.2 mg g(-1) dry matter, the light-exposed needles remained green, and the vascular bundles developed no anomalies. The data show that the rapid needle yellowing of ozone-exposed Mg-deficient needles did not depend on the collapse of the phloem. Mg deficiency played a key role in the development of anomalous vascular bundles under light, and also appears to explain the transient changes in sieve cell structure under shade. The role of Mg deficiency, rather than ozone pollution, in the damage of the sieve cells was confirmed in a long-term ozone exposure experiment with young clonal spruce growing under defined conditions.

Air Pollutants↗
PubMed2005

Phytochrome B in the mesophyll delays flowering by suppressing FLOWERING LOCUS T expression in Arabidopsis vascular bundles.

Light is one of the most important environmental factors that determine the timing of a plant's transition from the vegetative to reproductive, or flowering, phase. Not only daylength but also the spectrum of light greatly affect flowering. The shade of nearby vegetation reduces the ratio of red to far-red light and can trigger shade avoidance responses, including stem elongation and the acceleration of flowering. Phytochrome B (phyB) acts as a photoreceptor for this response. Physiological studies have suggested that leaves can perceive and respond to shade. However, little is known about the mechanisms involved in the processing of light signals within leaves. In this study, we used an enhancer-trap system to establish Arabidopsis thaliana transgenic lines that express phyB-green fluorescent protein (GFP) fusion protein in tissue-specific manners. The analysis of these lines demonstrated that phyB-GFP in mesophyll cells affected flowering, whereas phyB-GFP in vascular bundles did not. Furthermore, mesophyll phyB-GFP suppressed the expression of a key flowering regulator, FLOWERING LOCUS T, in the vascular bundles of cotyledons. Hence, a novel intertissue signaling from mesophyll to vascular bundles is revealed as a critical step for the regulation of flowering by phyB.

Arabidopsis↗
PubMed2005

Colonization of the Arabidopsis rhizosphere by fluorescent Pseudomonas spp. activates a root-specific, ethylene-responsive PR-5 gene in the vascular bundle.

Plants of which the roots are colonized by selected strains of non-pathogenic, fluorescent Pseudomonas spp. develop an enhanced defensive capacity against a broad spectrum of foliar pathogens. In Arabidopsis thaliana, this rhizobacteria-induced systemic resistance (ISR) functions independently of salicylic acid but requires responsiveness to jasmonic acid and ethylene. In contrast to pathogen-induced systemic acquired resistance (SAR), ISR is not associated with systemic changes in the expression of genes encoding pathogenesis-related (PR) proteins. To identify genes that are specifically expressed in response to colonization of the roots by ISR-inducing Pseudomonas fluorescens WCS417r bacteria, we screened a collection of Arabidopsis enhancer trap and gene trap lines containing a transposable element of the Ac/Ds system and the GUS reporter gene. We identified an enhancer trap line (WET121) that specifically showed GUS activity in the root vascular bundle upon colonization of the roots by WCS417r. Fluorescent Pseudomonas spp. strains P. fluorescens WCS374r and P. putida WCS358r triggered a similar expression pattern, whereas ISR-non-inducing Escherichia coli bacteria did not. Exogenous application of the ethylene precursor 1-aminocyclopropane-1-carboxylate (ACC) mimicked the rhizobacteria-induced GUS expression pattern in the root vascular bundle, whereas methyl jasmonic acid and salicylic acid did not, indicating that the Ds element in WET121 is inserted in the vicinity of an ethylene-responsive gene. Analysis of the expression of the genes in the close vicinity of the Ds element revealed AtTLP1 as the gene responsible for the in cis activation of the GUS reporter gene in the root vascular bundle. AtTLP1 encodes a thaumatin-like protein that belongs to the PR-5 family of PR proteins, some of which possess antimicrobial properties. AtTLP1 knockout mutant plants showed normal levels of WCS417r-mediated ISR against the bacterial leaf pathogen Pseudomonas syringae pv. tomato DC3000, suggesting that expression of AtTLP1 in the roots is not required for systemic expression of ISR in the leaves. Together, these results indicate that induction of AtTLP1 is a local response of Arabidopsis roots to colonization by non-pathogenic fluorescent Pseudomonas spp. and is unlikely to play a role in systemic resistance.

Amino Acid Sequence↗
PubMed1970

The relation of carbon dioxide compensation and chlorenchymatous vascular bundle sheaths in leaves of dicots.

Low CO(2) compensation points have been found to be associated with several unusual characteristics related to photosynthesis. One such characteristic is a prominent, chlorenchymatous vascular bundle sheath in the leaves. It has been suggested that the presence of this sheath in dicotyledons can serve as a means of detecting low CO(2)-compensating species. We collected 88 dicotyledon species from 22 families reported to have chlorenchymatous sheaths. Of the 88, only three, Tribulus terrestris, L., Boerhaavia paniculata, L. C. Rich, and Trianthema portulacastrum L., had low CO(2) compensation points. Cross sections of the leaves of the other species revealed that they did have chlorenchymatous vascular bundle sheaths. However, these sheath cells contained chloroplasts which were not specialized for starch formation as were the bundle sheath chloroplasts of the low CO(2)-compensating species.

Journal Article↗
PubMed2001

A Ca(2+)-dependent protein kinase that endows rice plants with cold- and salt-stress tolerance functions in vascular bundles.

A rice Ca(2+)-dependent protein kinase, OsCDPK7, is a positive regulator commonly involved in the tolerance to cold and salt/drought. We carried out in situ detection of the transcript and immunolocalization of the protein. In the wild-type rice plants under both stress conditions, OsCDPK7 was expressed predominantly in vascular tissues of crowns and roots, vascular bundles and central cylinder, respectively, where water stress occurs most severely. This enzyme was also expressed in the peripheral cylinder of crown vascular bundles and root sclerenchyma. Similar localization patterns with stronger signals were observed in stress-tolerant OsCDPK7 over-expressing transformants with the cauliflower mosaic virus 35S promoter. The transcript of a putative target gene of the OsCDPK7 signaling pathway, rab16A, was also detected essentially in the same tissues upon salt stress, suggesting that the OsCDPK7 pathway operates predominantly in these regions. We propose that the use of the 35S promoter fortuitously strengthened the localized expression of OsCDPK7, resulting in enhancement of the stress signaling in the inherently operating regions leading to improved stress tolerance.

Adaptation, Physiological↗
PubMed2002

Genes from the APETALA3 and PISTILLATA lineages are expressed in developing vascular bundles of the tuberous rhizome, flowering stem and flower Primordia of Eranthis hyemalis.

In Arabidopsis thaliana expression of the B-class MADS-box genes APETALA3 (AP3) and PISTILLATA (PI) is confined to petals and stamens but in other plant species these genes are also transcribed in non-flower tissues; in Solanum tuberosum they are transcribed specifically in vascular bundles leading to petals and stamens. Transcription analysis of B-class genes in Eranthis hyemalis using reverse transcribed in situ PCR revealed that both AP3 and PI are expressed in developing vascular bundles in the tuberous rhizome, flowering stem and floral primordia. In addition, AP3 and PI transcripts are also found in stems and leaves. These results suggest a more complex role of B-class genes in Eranthis and possible involvement in the development of vascular tissue.

Gene Expression Regulation, Plant↗
PubMed1989

Vascular bundles and wickerworks in childhood brain tumors.

We reviewed 114 childhood brain tumors and brain sections from 30 children with no nervous system lesions to determine the incidence of vascular bundles (VB) and vascular wickerworks (VW). VB consist of a group of small blood vessels running parallel to each other. VW denote spiralling or twisting of two or more small blood vessels around one another, resembling vines. By light microscopy, VB cannot be differentiated from VW; both appear as a group of small blood vessels oriented in the same direction. VB and VW have been described in normal and abnormal brains at all ages, in association with aging, in neovascularization following necrosis, and in brain tumors. They occur rarely in normal brains, but are a common histological feature of cerebellar pilocytic astrocytomas in contrast to diencephalic pilocytic astrocytomas, anaplastic astrocytomas of cerebrum and cerebellum, and meningiomas.

Adolescent↗
PubMed2002

A xylanase, AtXyn1, is predominantly expressed in vascular bundles, and four putative xylanase genes were identified in the Arabidopsis thaliana genome.

The cDNA clone RXF12, which encodes a xylanase (EC 3.2.1.8), was isolated from Arabidopsis thaliana. The C-terminal half of the amino acid sequence of the deduced protein, named AtXyn1, showed similarity with the catalytic domain of barley xylanase X-1. The N-terminal half of AtXyn1 also contained three regions with sequences similar to cellulose-binding domains (CBDs). A xylanase assay revealed that transgenic A. thaliana plants expressing exogenous AtXyn1 fused with enhanced green fluorescent protein (EGFP) possessed approximately twice as much xylanase activity as wild-type plants. Observation by fluorescence microscopy of transgenic A. thaliana plants expressing a fusion protein of AtXyn1 and EGFP suggested that AtXyn1 is a cell wall protein. Analysis of the localization of beta-glucuronidase (GUS) activity in transgenic A. thaliana plants containing a chimeric gene with the upstream sequence of the AtXyn1 gene and the GUS gene demonstrated that the AtXyn1 gene is predominantly expressed in vascular bundles, but not in vessel cells. These data suggest that AtXyn1 is involved in the secondary cell wall metabolism of vascular bundle cells. A database search revealed that four putative xylanase genes exist in the A. thaliana genome, besides the AtXyn1 gene. Of these, two also contain several regions with sequences similar to CBDs in their N-terminal regions. Comparison of the amino acid sequences of the five xylanases suggests a possible process for their molecular evolution.

Amino Acid Sequence↗
PubMed2000

Tissue-specific oxylipin signature of tomato flowers: allene oxide cyclase is highly expressed in distinct flower organs and vascular bundles.

A crucial step in the biosynthesis of jasmonic acid (JA) is the formation of its correct stereoisomeric precursor, cis(+)12-oxophytodienoic acid (OPDA). This step is catalysed by allene oxide cyclase (AOC), which has been recently cloned from tomato. In stems, young leaves and young flowers, AOC mRNA accumulates to a low level, contrasting with a high accumulation in flower buds, flower stalks and roots. The high levels of AOC mRNA and AOC protein in distinct flower organs correlate with high AOC activity, and with elevated levels of JA, OPDA and JA isoleucine conjugate. These compounds accumulate in flowers to levels of about 20 nmol g-1 fresh weight, which is two orders of magnitude higher than in leaves. In pistils, the level of OPDA is much higher than that of JA, whereas in flower stalks, the level of JA exceeds that of OPDA. In other flower tissues, the ratios among JA, OPDA and JA isoleucine conjugate differ remarkably, suggesting a tissue-specific oxylipin signature. Immunocytochemical analysis revealed the specific occurrence of the AOC protein in ovules, the transmission tissue of the style and in vascular bundles of receptacles, flower stalks, stems, petioles and roots. Based on the tissue-specific AOC expression and formation of JA, OPDA and JA amino acid conjugates, a possible role for these compounds in flower development is discussed in terms of their effect on sink-source relationships and plant defence reactions. Furthermore, the AOC expression in vascular bundles might play a role in the systemin-mediated wound response of tomato.

Cyclopentanes↗
PubMed1996

[Experimental study on vascularized area of the prefabricated axial skin flap after implantation of vascular bundles].

Thirty-eight New Zealand white male rabbits were used to study vascularized area of the prefabricated axial skin flaps (PASFs) after implantation of vascular bundles (VBs) into subcutaneous tissues of the animal's abdomen. Influential factors were investigated including the interval after implantation, the size of VBs, the subcutaneous layer where VBs were implanted and simultaneous skin expansion. The results indicated that the suitable time for PASFs transferring was 3-4 weeks after implantation of VBs. The VBs of larger diameter prefabricated larger area of PASFs. Larger areas of PASFs were created by implanting VBs into the subcutaneous layers that possessed rich vascular plexuses. It was possible that the expanded PASFs could be transferred.

Animals↗
PubMed1999

[Vascular bundle specific expression of iaaL gene affects the generation frequencies of transgenic tobacco].

A vascular bundles specific expressing vector pBAL1 with a promoter AQ630 from rice phenylalanine ammonialyase gene and a gene encoding indoleacetic-lysine synthytase from Pseudomonas syringae subsp. savastanoi was constructed. Affirmed by Southern blotting and RTPCR analysis, the AQ630-iaaL transgenic plants show increasing shoots-regeneration frequency of young stem explants on hormone-free 1/2 MS medium and lower sensibility to IAA when roots were induced from the root explants on the media containing different concentrations of IAA compared to untransformed plants.

Culture Techniques↗
PubMed1995

Transposition of the ulnar nerve and its vascular bundle for the entrapment syndrome at the elbow.

Surgical findings show important alterations of the extrinsic and intrinsic vascularity of the ulnar nerve in the epitroclear groove. Current procedures are only able to solve the mechanical aspect of nerve compression. Transposition may cause additional iatrogenic ischaemic damage of endoneural vascularity if the nerve is separated from the ulnar collateral artery to achieve anterior mobilization. Our technique of transposition of the ulnar nerve with its vascular bundle maintains the advantages of anterior transposition currently in use, but is able to preserve the whole vascularity of the nerve, thus solving the biological aspect of nerve compression. This allows quicker recovery of axonal activity that was chronically compromised by the entrapment neuropathy. The technique and the results in 30 patients (90% excellent and good, 10% fair) treated since 1987 are presented.

Adult↗
PubMed1996

Vascular bundle implantation into bone for aseptic necrosis of the lunate.

Since April 1986, implantation of a vascular bundle containing the ramus carpeus dorsalis of the interosseal anterior artery and vein into the lunate has been undertaken for aseptic necrosis of the lunate bone. A series of 11 cases were performed in East-South Hospital with satisfactory results. The average follow-up period was 36 months. A series of follow-up roentgenograms reveal that necrosis of the lunate bone is being continuously repaired. Fourteen months postoperative, the following results are obtained: (1) the sclerosis of the lunate bone has completely disappeared on the roentgenograms, (2) the architecture and density of the lunate bone have returned to normal on the roentgenograms, (3) technically colorized X-ray films show that lunate bone density decreases after the operation (the decreasing range is 20 to 44 Gray scale [mean, 30.3 +/- 2.4 Gray scale]) and that the cyst formations on the lunate bone have completely disappeared postoperatively, and (4) pain in the affected wrists disappeared and patients have returned to their former work, including manual labor. The necrotized lunate bones are healed. Anatomic study shows that the presence of the ramus carpeus dorsalis of the interosseal anterior artery and vein on the wrist is 100%, and the structure as well as location of the ramus carpeus dorsalis has little anatomic variation and is long enough to be transplanted into the lunate bone.

Adult↗
PubMed2000

Sequence-specific and methylation-dependent and -independent binding of rice nuclear proteins to a rice tungro bacilliform virus vascular bundle expression element.

Nuclear proteins from rice (Oryza sativa) were identified that bind specifically to a rice tungro bacilliform virus promoter region containing a vascular bundle expression element (VBE). One set of proteins of 29, 33, and 37 kDa, present in shoot and cell suspension extracts but hardly detectable in root extracts, bound to a site containing the sequence AGAAGGACCAGA within the VBE, which also contains two CpG and one CpNpG potential methylation motifs. Binding by these proteins was determined to be cytosine methylation-independent. However, a novel protein present in all analyzed extracts bound specifically to the methylated VBE. A region of at least 49 nucleotides overlapping the VBE and complete cytosine methylation of the three Cp(Np)G motifs was required for efficient binding of this methylated VBE-binding protein (MVBP).

5-Methylcytosine↗
PubMed2000

[An experimental study of transplantation of prefabricated axial flap with an vascular bundle].

OBJECTIVE: To study the prognostic results of different prefabricated axial flaps with different operative methods. METHODS: Eighteen New Zealand rabbits and two operative patterns were utilized in this study. In group A, the vascular bundles of the left ear were transferred through tube flaps to the left neck. In group B, the central artery and veins of the right ear were transposed through skin tunnel to the right neck. After 4 weeks of operation, transplantation and vessel perfusion were made. RESULTS: Group A: The flaps of 10 cases were 100% survival, while there were 2 cases with 85% survival, and 2 flaps with necrosis. Group B: The flaps of 8 cases were 100% survival, while there were 5 sides with 50%-85% survival and 1 necrotic flap. The vessel perfusion demonstrated that there was no difference between the density values of the direct sprouting vessels from the transplanted vascular pedicles. There was no statistical difference between the two groups in flap survival and vessel perfusion. CONCLUSION: There is no obvious difference between the above two methods of prefabricated axial flap.

Animals↗