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At least 181 records · Page 10Linked to original sources
PubMed1998

Spatial specificity of H2O2-generating oxalate oxidase gene expression during wheat embryo germination.

Germin, a molecular marker of wheat embryo germination, is a protease-resistant, apoplastic, homopentameric glycoprotein with peroxide-generating oxalate oxidase activity. The spatial specificity of germin-like oxalate oxidase (gl-OXO) gene expression has been determined in tissues of germinating wheat embryos by a combination of histochemical, immunocytochemical and in situ hybridization techniques. The synthesis and accumulation of gl-OXO mRNA and protein is localised within the enveloping tissues of the embryonic axis (particularly the coleorhiza) during the first 24 h of imbibition. By 48 h germination, gl-OXO accumulation is detected throughout the root, with the exception of the postmitotic zone of cell elongation, where accumulation of its transcript is restricted to outer cell layers. At this time in the elongating shoot, gl-OXO is restricted to the coleoptile where it is detected only in the epidermal cell layer, the vascular bundles and bundle sheath cells. In older seedlings (approximately 9 days post-imbibition) gl-OXO activity is detected in leaves, but only within the vascular bundles. These patterns of expression are consistent with the hypothesis that the biological function of gl-OXO is to restrict cell growth by participating in cell-wall restructuring through the local provision of hydrogen peroxide for cross-linking of wall components.

Gene Expression Regulation, Developmental↗
PubMed2000

Identification of a new glucosinolate-rich cell type in Arabidopsis flower stalk.

Distribution of K, Ca, Cl, S, and P in freeze-dried sections of Arabidopsis flower stalk was analyzed by energy dispersive x-ray imaging. Concentrations of these elements in different cell types were quantified by microanalysis of single-cell samples and phloem exudates. Results showed a differential pattern of distribution for all five elements. K concentration was found to be highest in the parenchymatous tissue around vascular bundles. Ca and Cl were present mainly in the central part of the flower stalk. P was largely located in the bundles and in the parenchyma surrounding them. S signal was extraordinary high in groups of cells (S-cells) situated between the phloem of every vascular bundle and the endodermis. Enzymatic hydrolysis by thioglucosidase of cell sap collected from S-cells using a glass microcapillary resulted in the release of glucose, indicating that these cells contain glucosinolates at high (> 100 mM) concentration, which is consistent with the concentration of S (> 200 mM) estimated by x-ray analysis of cell sap samples. Since their position outside of the phloem is ideally suited for protecting the long-distance transport system from feeding insects, the possible roles of these cells as components of a plant defense system are discussed.

Arabidopsis↗
PubMed1997

The Spatial Distribution of Sucrose Synthase Isozymes in Barley.

The sucrose (Suc) synthase enzyme purified from barley (Hordeum vulgare L.) roots is a homotetramer that is composed of 90-kD type 1 Suc synthase (SS1) subunits. Km values for Suc and UDP were 30 mM and 5 [mu]M, respectively. This enzyme can also utilize ADP at 25% of the UDP rate. Anti-SS1 polyclonal antibodies, which recognized both SS1 and type 2 Suc synthase (SS2) (88-kD) subunits, and antibodies raised against a synthetic peptide, LANGSTDNNFV, which were specific for SS2, were used to study the spatial distribution of these subunits by immunoblot analysis and immunolocalization. Both SS1 and SS2 were abundantly expressed in endosperm, where they polymerize to form the five possible homo- and heterotetramers. Only SS1 homotetramers were detected in young leaves, where they appeared exclusively in phloem cells, and in roots, where expression was associated with cap cells and the vascular bundle. In the seed both SS1 and SS2 were present in endosperm, but only SS1 was apparent in the chalazal region, the nucellar projection, and the vascular bundle. The physiological implications for the difference in expression patterns observed are discussed with respect to the maize (Zea mays L.) model.

Journal Article↗
PubMedDate not supplied

[Method of surgical treatment of inferior alveolar nerve neuralgia].

It was established in experiments on dogs that after resection of a part of the neuro-vascular bundle of the mandibular canal with removal of its peripheral segment the inferior alveolar nerve does not regenerate. Resection of a part of the neuro-vascular bundle of the mandibular canal with resection of its peripheral segment caused satisfactory immediate and late results in 86 patients with neuralgia of the inferior alveolar nerve. The operative techniques are described.

Adult↗
PubMed2001

[The morphological and histological identification of Boschniakia rossica].

In this paper the descriptions and microscopic characters of Boschniakia rossica were recounted. The evidences of the identication were presented. The differences between Boschniakia rossica and its similar species Cistanche deserticola and Cynomrium songaricum were also summed up. Boschniakia rossica: Stem thin. Cross section hollow, brittle in texture, with cortex. Stele vascular bundles arranged in ring, pith obvious. Cistanche deserticola and Cynomrium songaricum: Stem thick and strong. Cross section solid, without cortex. Hard in texture. Pith unobvious. The stele vascular bundle of Cistanche deserticola arranged in wavy ring. That of Cynomrium songaricum irregularly arranged.

Cistanche↗
PubMedDate not supplied

Root, stem and leaf anatomy of Geranium palustre Torner Cent. (Geraniaceae).

An anatomical study on the root, stem and leaf of Geranium palustre Torner Cent. has been performed in order to continue our previous researches on this species. Technique of inclusion into paraffin and optical microscope have been used. Root, stem and leaf transverse sections were studied. They contain calcium oxalate crystals as inclusions. The root presents elements of secondary structure (suber, secondary cortex, secondary xylem and phloem). The vascular bundles in the stem can be classified as internal or external and differ in the presence or absence of an own sclerenchyma sheet depending on their age. The vascular bundles of stem are collateral. Leaf structure is bi-facial. Stem and leaf surface have no glandular hairs.

Calcium Oxalate↗
PubMed1994

Reconstruction of blood flow distribution in the rat kidney during postischemic renal failure.

Inner medullary blood flow has been found to remain nearly unchanged during postischemic renal failure, despite a severely disturbed perfusion in the outer medulla. In order to elucidate this discrepancy, rats were subjected to 1 h left renal artery occlusion and 1 h reflow. The blood plasma was then labeled by dye-conjugated globulin for 1 min. The in vivo indicator distribution was histologically analyzed, especially in the medullary vascular bundles. The filling there was observed along a section plane positioned through the inner stripe along the long and the short axis of the organ. Vessels centrally located within the bundles were more labeled than those in the periphery of the bundles. In addition, the degree of filling on the whole was almost twice as high in the tissue near the renal sinus as in the central area. At the same time, filling defects in the renal papilla were restricted mostly to the center of that tissue. The observations support the assumption that differences in blood flow obstruction exist within each bundle. They also show that perfusion defects of the outer medulla occur more readily in the center of the organ, thus allowing blood to enter the inner medulla via vascular bundles located marginally, adjacent to the renal sinus of the kidney.

Animals↗
PubMed2002

Epifluorescent and histochemical aspects of shoot anatomy of Typha latifolia L., Typha angustifolia L. and Typha glauca Godr.

Using epifluorescent and histochemical techniques, we examined anatomical differences in the shoot organs of Typha latifolia, T. angustifolia and T. glauca. The leaf lamina of T. latifolia and T. glauca had enlarged epidermal cells and a thickened cuticle above the subepidermal vascular bundles; that of T. angustifolia lacked these characteristics. Leaf sheaths were similar among the species and all lacked the epidermal thickenings found in the lamina. The fertile stems had typical scattered vascular bundles with a band of fibres that was most prominent in T. glauca. The sterile stems were only 1 cm in length and contained a multiseriate hypodermis and a uniseriate endodermis over part of their length. The rhizomes were similar except for a pronounced band of fibres surrounding the central core in T. angustifolia. The rhizome was also characterized by an outer cortical region with a large multiseriate hypodermis/exodermis and a uniseriate endodermis with Casparian bands, suberin lamellae and secondarily thickened walls.

Fluorescent Dyes↗
PubMed1975

Histochemical and biochemical observations on storage protein metabolism and protein body autolysis in cotyledons of germinating mung beans.

Storage protein hydrolysis in the cotyledons of germinating mung beans (Phaseolus aureus Roxb.) was examined by histochemical techniques, and the autolytic capacity of isolated protein bodies was studied with biochemical methods. The localization of endopeptidase activity within the cotyledons was studied using an India ink-gelatin film technique. After 24 hours of imbibition, a low level of endopeptidase activity was found throughout the storage tissues of the cotyledons. A marked increase in activity was noted in cells farthest from the vascular bundles 48 to 60 hours after the start of imbibition. The decrease in storage protein followed the same spatial distribution starting in the cells farthest from the bundles. The cotyledons contain a population of cells in various stages of endopeptidase activity enhancement and storage protein degradation. A wave of endopeptidase activity moves progressively through the cotyledons towards the vascular bundles leaving behind areas devoid of stored reserves and low in endopeptidase activity. Observations on the morphology of protein bodies during germination indicate that the membrane surrounding them remains intact, while the reserves disappear. This result suggests that the protein bodies may be undergoing autolysis. To determine whether this may indeed be the case, protein bodies were isolated from the meal of mung bean seeds using an aqueous medium containing 80% glycerol. The protein body preparations and the cytoplasm were assayed for the presence of a number of enzymes which may be involved in the breakdown of the storage proteins. The protein bodies contained all, or nearly all, of the carboxypeptidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, and caseolytic activity. The cytoplasm contained all, or most, of the leucine aminopeptidase and the trypsin-like activity (benzoyl arginine-p-nitroanalide as substrate). Incubation of the isolated protein bodies resulted in the release of amino acids. An analysis of the products of hydrolysis indicated that very little, if any, storage protein was being hydrolyzed during the incubation. Hydrolysis of the storage proteins present in the protein bodies was greatly accelerated by the addition of extracts from the cotyledons of 4-day-old seedlings. The results suggest that new enzymic activities not present in the protein bodies isolated from dry seeds must either be activated or synthesized and possibly added to the protein bodies before storage protein breakdown can begin.

Journal Article↗
PubMed2002

Lotus japonicus gene Ljsbp is highly conserved among plants and animals and encodes a homologue to the mammalian selenium-binding proteins.

We have isolated and characterized a Lotus japonicus gene (Ljsbp) encoding a putative polypeptide with striking homology to the mammalian 56-kDa selenium-binding protein (SBP). cDNA clones homologous to LjSBP were also isolated from soybean, Medicago sativa, and Arabidopsis thaliana. Comparative expression studies in L japonicus and A. thaliana showed that sbp transcripts are present in various tissues and at different levels. Especially in L japonicus nodules and seedpods and A. thaliana siliques, sbp expression appears to be developmentally up-regulated. sbp Gene transcripts were localized by in situ hybridization in the infected cells and vascular bundles of young nodules, while in mature nodules, low levels of expression were only detected in the parenchymatous cells. Expression of sbp transcripts in young seedpods and siliques was clearly visible in vascular tissues and embryos, while in embryos, low levels of expression were detected in the root epidermis and the vascular bundles. Polyclonal antibodies raised against a truncated LjSBP recombinant protein recognized a polypeptide of about 60 kDa in nodule extracts. Immunohistochemical experiments showed that accumulation of LjSBP occurred in root hairs, in the root epidermis above the nodule primordium, in the phloem of the vasculature, and abundantly in the infected cells of young nodules. Irrespective of the presence of rhizobia, expression of SBP was also observed in root tips, where it was confined in the root epidermis and protophloem cells. We hypothesize that LjSBP may have more than one physiological role and can be implicated in controlling the oxidation/reduction status of target proteins, in vesicular Golgi transport, or both.

Amino Acid Sequence↗
PubMed2006

Newly featured infection events in a supernodulating soybean mutant SS2-2 by Bradyrhizobium japonicum.

Supernodulating soybean (Glycine max L. Merr.) mutant SS2-2 and its wild-type counterpart, Sinpaldalkong 2, were examined for the microstructural events associated with nodule formation and development. SS2-2 produced a substantially higher percentage of curled root hairs than the wild type, especially at 14 days after inoculation with Bradyrhizobium japonicum. In addition, there was new evidence that in SS2-2, B. japonicum also entered through fissures created by the emerging adventitious root primordia. Early steps of nodule ontogeny were faster in SS2-2, and continued development of initiated nodules was more frequent and occurred at a higher frequency than in the wild type. These data suggest that the early expression of autoregulation is facilitated by decreasing the speed of cortical cell development, leading to the subsequent termination of less-developed nodules. The nodules of SS2-2 developed into spherical nodules like those formed on the wild type. In both the wild type and supernodulating mutant, vascular bundles bifurcate from root stele and branch off in the nodule cortex to surround the central infected zone. These findings indicate that SS2-2 has complete endosymbiosis and forms completely developed nodule vascular bundles like the wild type, but that the speed of nodule ontogeny differs between the wild type and SS2-2. Thus, SS2-2 has a novel symbiotic phenotype with regard to nodule organogenesis.

Bradyrhizobium↗
PubMed1995

Prostaglandin E2 abrogates endothelin-induced vasoconstriction in renal outer medullary descending vasa recta of the rat.

Endothelins (ET) and prostaglandin E2 are synthesized in the inner medulla by collecting duct epithelium and interstitial cells, respectively. All ascending vasa recta (AVR) blood returns from the inner medulla to the cortex in outer medullary vascular bundles. We reasoned that hormones might influence medullary blood flow by diffusing across AVR fenestrations to modulate vasoconstriction of outer medullary descending vasa recta (OMDVR). To investigate this possibility, OMDVR dissected from vascular bundles were exposed to ET-1, 2, or 3. Each endothelin isoform induced stable vasoconstriction with potency, ET-1 > ET-2 > ET-3 (EC50, 1.8 x 10(-15), 5.9 x 10(-12), and 8.8 x 10(-10) M, respectively). The ETA receptor antagonist BQ-123 and BQ-610 (10(-6) M), as well as an ETA and ETB receptor antagonist combination, attenuated vasoconstriction due to ET-1 (10(-12) M). BQ-123 had no effect on the response to ET-3 (10(-8) M). The ETB receptor antagonist BQ-788 (10(-6) M) attenuated the response to ET-3 (10(-10) M), but not that to ET-1 (10(-12) M). Finally, PGE2 (10(-6) M) reversibly dilated OMDVR preconstricted with ET-1 (10(-12) M) or ET-3 (10(-8) M) but not ET-1 (10(-10) M). We conclude that ET-1,2, and 3 are potent constrictors of OMDVR and the response to ET-1 is mainly ETA receptor subtype mediated, while ET-3 acts via the ETB. PGE2 modulates ET induced constriction. These findings are consistent with interactive feedback and control of medullary perfusion by locally synthesized hormones.

Animals↗
PubMed1998

Transplantation of vascularized allogeneic skeletal muscle for scalp reconstruction in a renal transplant patient.

BACKGROUND: We report the case of a vascularized allogeneic skeletal muscle transplant (VASM) and autologous skin grafting as rescue therapy for refractory squamous cell carcinoma of the scalp. METHODS: A renal transplant recipient with recurrent squamous carcinoma of the scalp underwent an excision that resulted in a 11 x 14 cm2 scalp defect with exposed cranium. At the time of multiorgan procurement, a section of rectus abdominis and external oblique muscle and fascia with its independent vascular bundle was isolated and stored in cold University of Wisconsin solution. The patient received methylprednisolone and rabbit antithymocyte globulin intravenously during scalp preparation, before single-vessel anastomosis of the deep inferior epigastric vascular bundle from the donor muscle to the recipient neck vessels. An autologous split-thickness skin graft was secured to the surface of the allogeneic muscle. RESULTS: Immunosuppression was maintained with prednisone and cyclosporine. Serial VASM biopsies were used to evaluate acute rejection. Perivascular lymphocytic infiltrates and rare focal myonecrosis were evident on biopsy at 2 weeks postoperatively, and mycophenolate mofetil was added. Subsequent VASM biopsies showed predominately interstitial and perivascular T-cell lymphocytic infiltrates interpreted as consistent with mild rejection, but the allograft appeared intact without clinical evidence of rejection. On postoperative week 18, the mycophenolate mofetil was discontinued. There has been no evidence of recurrence or metastasis. The patient remains ambulatory with a healed scalp 12 months after the VASM. CONCLUSION: The success of this first allogeneic skeletal muscle transplant is encouraging and provides another reconstruction option for wounds in transplant patients on chronic immunosuppression.

Animals↗
PubMed1996

[Studies on Cnidium fruits by stereological method and computer image analysis].

The fruits, pollen grains, vascular bundles, stomata and endosperm cells of 4 Cnidium species were studied and determined by stereological method and computer image analysis technique. Statistical data were presented. In the volume of fruit and the area of vascular bundle, Cnidium dahuricum is the biggest, then C. salinum, C. japonicum and C. monnieri successively. In the volume of pollen grain,C. salinum is the biggest, followed by C. dahuricum, C. japonicum and C. monnieri in succession. In the volume of endosperm cell, C. dahuricum is also the biggest, and then C. japonicum, C. salinum and C. monnieri in order.

Fruit↗
PubMed1996

The expression pattern of alfalfa flavanone 3-hydroxylase promoter-gus fusion in Nicotiana benthamiana correlates with the presence of flavonoids detected in situ.

Flavanone 3-hydroxylase is an enzyme acting in the central part of the flavonoid biosynthesis pathway. It is generally encoded by a single gene and seems to have a key position for the regulation in this pathway. These two features make a single f3h promoter-gus fusion a suitable tool to study both the f3h expression and the regulation of this pathway. We present here the spatial and temporal analysis of the expression of an alfalfa flavanone 3-hydroxylase (f3h) promoter-gus fusion introduced into Nicotiana benthamiana. The Medicago sativa (alfalfa) f3h promoter directed gus expression in flowers, stems, leaves and roots. In flowers, GUS activity was observed in pollen grains, in ovules, in ovary placenta and in the epidermis, medullary parenchyma, trichomes and second cortical cellular layer surrounding the vascular bundles of the peduncle. In stems, GUS activity was detected at the same places as in the peduncle except for the medullary parenchyma. In roots, we found GUS staining in root hairs, epidermis and in the vascular bundles of the elongated zone. Finally, in leaves, the f3h promoter expressed essentially in the stalk cells of the multicellular trichomes. The expression pattern of the f3h-gus fusion was correlated to the presence of flavonoids in situ. These data indicate that this construct can be very useful to study factors controlling the production of flavonoids.

Base Sequence↗
PubMed1966

Sites of accumulation in excised Phloem and vascular tissues.

Excised pieces of vascular bundle and phloem tissue were allowed to accumulate radioactive phosphate and sulfate, and were then sectioned and autoradiographed so as to detect the sites of accumulation. Special methods were needed to prevent any diffusion of the radioisotope. Some autoradiographs obtained are presented. In excised celery vascular bundles, the most radioactive area and hence the most actively accumulating tissue was the young secondary phloem at the sides of the bundle. In intact plants, the same tissue was the most active in translocating. In excised apple phloem there was some variation in behavior, but again the young secondary phloem was generally the most actively accumulating tissue. Accumulation activities of individual cells in the phloem and vascular tissue were compared. It appeared that all cell types, ray, phloem and xylem parenchyma, cambial cells and sieve tubes, accumulated at least 5 times more actively than did the cortical parenchyma cells. The sieve tubes were among the most actively accumulating cells present, accumulating 20 times more actively than the cortical parenchyma cells. It is concluded that accumulation processes have a primary role to play in the mechanism of phloem transport.

Journal Article↗
PubMed2001

Botrytis cinerea induces the formation of free radicals in fruits of Capsicum annuum at positions remote from the site of infection.

Free radical adducts of the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone have been observed by electron paramagnetic resonance spectroscopy in detached fruits of Capsicum annuum investigated 5 days after infection with Botrytis cinerea. The spectra of these adducts were at a maximum within the soft rot lesion, but they could also be detected at distances up to 50 mm from the edge of the lesion in samples following main vascular bundles. At distances greater than 40 mm, the spectrum of the ascorbate radical was also seen, and at greater distances from the lesion it was the only radical detected. With samples taken from parenchyma tissue adjacent to the vascular bundles there was little adduct formation and the ascorbate radical could be detected, albeit with reduced intensity compared to healthy tissue, at distances as small as 10 mm from the edge of the lesion. This observation of chemical changes at considerable distances from the infected tissue is in contrast to previous observations on the behaviour of other markers of oxidative stress (e.g., 4-hydroxynonenal, malondialdehyde, single-peak free radical, and Fe(III) (g = 4.27) electron paramagnetic resonance signals), where their levels decreased rapidly outside of the soft rot.

Botrytis↗
PubMed1995

Phloem Loading by the PmSUC2 Sucrose Carrier from Plantago major Occurs into Companion Cells.

High levels of mRNA for the sucrose-H+ symporter PmSUC2 have been found in the vascular bundles of petioles from Plantago major. The possible role of PmSUC2 in phloem loading was studied with antiserum raised against the recombinant PmSUC2 protein. This antiserum labeled a single 35-kD protein band in detergent extracts of P. major vascular bundles. It showed no cross-reaction with the P. major sucrose carrier PmSUC1, which was tested with detergent extracts from plasma membranes of transgenic yeast strains containing either the P. major sucrose transporter PmSUC1 or PmSUC2. The antiserum was used to determine the site of PmSUC2 expression in leaves, petioles, and roots of P. major. In cross-sections and longitudinal sections, the PmSUC2 protein was found in only one single cell type. These cells were identified as companion cells because they are nucleated, contain a dense cytoplasm, and are always adjacent to a sieve element. The labeled cells had the same longitudinal extension as did their sister sieve elements and always ended next to the sieve plates, which were characterized by specific staining. PmSUC2 mRNA and PmSUC2 protein were also detected in P. major roots. The function of PmSUC2 in the different organs and its role in phloem loading are discussed.

Journal Article↗