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At least 523 records · Page 29Linked to original sources
PubMed2005

Expression of allene oxide cyclase and accumulation of jasmonates during organogenic nodule formation from hop (Humulus lupulus var. Nugget) internodes.

A crucial step in the biosynthesis of jasmonic acid (JA) is the formation of its stereoisomeric precursor, cis-(+)-12-oxophytodienoic acid (OPDA), which is catalyzed by allene oxide cyclase (AOC, EC 5.3.99.6). A cDNA of AOC was isolated from Humulus lupulus var. Nugget. The ORF of 765 bp encodes a 255 amino acid protein, which carries a putative chloroplast targeting sequence. The recombinant protein without its putative chloroplast target sequence showed significant AOC activity. Previously we demonstrated that wounding induces organogenic nodule formation in hop. Here we show that the AOC transcript level increases in response to wounding of internodes, peaking between 2 and 4 h after wounding. In addition, Western blot analysis showed elevated levels of AOC peaking 24 h after internode inoculation. The AOC increase was accompanied by increased JA levels 24 h after wounding, whereas OPDA had already reached its highest level after 12 h. AOC is mostly present in the vascular bundles of inoculated internodes. During prenodule and nodule formation, AOC levels were still high. JA and OPDA levels decreased down to 10 and 118 pmol (g FW)(-1), respectively, during nodule formation, but increased during plantlet regeneration. Double immunolocalization analysis of AOC and Rubisco in connection with lugol staining showed that AOC is present in amyloplasts of prenodular cells and in the chloroplasts of vacuolated nodular cells, whereas meristematic cells accumulated little AOC. These data suggest a role of AOC and jasmonates in organogenic nodule formation and plantlet regeneration from these nodules.

Amino Acid Sequence↗
PubMed2005

Expression of the vacuolar Ca2+/H+ exchanger, OsCAX1a, in rice: cell and age specificity of expression, and enhancement by Ca2+.

Calcium is an essential macronutrient for plants and functions in signal transduction. Regulation of the cytosolic calcium concentration is required for normal cell growth. In calcium homeostasis in plant cells, Ca(2+)/H(+) exchangers are involved in Ca(2+) compartmentalization into intracellular compartments. Here, we examine the intracellular localization of a rice Ca(2+)/H(+) exchanger, OsCAX1a, fused to a green fluorescent protein and transiently expressed in onion epidermis and rice protoplasts. Green fluorescence was observed in the vacuolar membrane. After sucrose gradient centrifugation of the homogenate of rice plants, OsCAX1a was detected in the same fraction as the vacuolar membrane aquaporin gamma-TIP. We then quantified the mRNA and protein of OsCAX1a in plants grown with metal ions. OsCAX1a mRNA was induced in roots by high concentrations of Ca(2+). The protein level in shoots was also increased in the presence of high concentrations of Ca(2+). Furthermore, transgenic rice plants transformed with the OsCAX1a promoter fused to beta-glucuronidase showed reporter expression in vascular bundles, stomata, trichomes, steles, flowers, embryos and aleurone layers. In the case of stomata and trichomes, transcription of OsCAX1a was particularly high in aged organs. These results suggest that OsCAX1a transports Ca(2+) into vacuoles and is involved in Ca(2+) homeostasis in cells that suffer from high concentrations of Ca(2+).

Antiporters↗
PubMed2006

ACT domain repeat protein 7, ACR7, interacts with a chaperone HSP18.0-CII in rice nuclei.

The regulatory ACT domains serve as amino acid-binding sites in some amino acid metabolic enzymes and transcriptional regulators in bacteria. To elucidate the molecular roles of the glutamine (Gln)-sensing system in nitrogen (N) metabolism in plants, we isolated six genes encoding ACT domain repeat proteins (ACR1, and ACR5-ACR9) from rice (Oryza sativa L.) using genomic information on the primary structure composed of four copies of the domain homologous to those of bacterial Gln sensor GLND. Since expression of ACR7 was the most abundant of the six ACR orthologous genes, we focused on this ACR in the current study. Gene products of ACR7 were most abundant in young developing leaf blades of rice, and ACR7 protein is specifically localized in the nucleus of the parenchyma cells of phloem and xylem in the vascular bundles. A yeast two-hybrid screen identified a small heat stress protein (HSP18.0-CII) as a protein interacting with ACR7. Transient expression analysis of HSP18.0-CII:sGFP in cultured rice cells, followed by co-immunoprecipitation, suggests that the nuclear ACR7 indeed interacted with nucleocytoplasmic HSP18.0-CII in vivo. The potential ability of nuclear protein ACR7 to bind Gln and the possibility of the protein acting as a Gln sensor in rice leaves is discussed.

Amino Acid Sequence↗
PubMed1997

Histology of magnesium-deficient Norway spruce needles influenced by nitrogen source.

Effects of magnesium deficiency and variation in nitrate to ammonium ratio on needle histology and chlorophyll concentration were investigated in current-year and one-year-old needles of clonal Norway spruce trees (Picea abies (L.) Karst.). Six-year-old trees were grown for one year in sand culture with circulating nutrient solutions containing a sufficient (0.2 mM) or a limiting (0.04 mM) concentration of Mg. The nitrogen concentration was not varied (5 mM), but the NO(3) (-)/NH(4) (+)-ratio was adjusted to 0.76 in Mg-sufficient and to 1.86, 0.76 or 0.035 in Mg-limited plants. Visible symptoms of Mg deficiency occurred only in current-year needles, indicating adequate Mg nutrition before the experiment. Under conditions of Mg limitation, chlorophyll and Mg concentrations were lowest in needles of trees supplied with NH(4) (+) as the major nitrogen source and highest in needles of trees supplied with NO(3) (-) as the major nitrogen source. In current-year and one-year-old needles, starch accumulation induced by Mg deficiency was increased when NH(4) (+) was the major nitrogen source. The accumulation of tannin spherules in current-year needles, which occurred in response to Mg deficiency, also increased with decreasing NO(3) (-)/NH(4) (+)-ratios. Deficient Mg supply caused premature aging in tissues of the vascular bundle, as indicated by modifications of the cambium and increased amounts of collapsed sieve cells. The number of collapsed sieve cells was slightly lower in needles grown in a NH(4) (+)-dominated nutrient regime than in needles grown in a NO(3) (-)-dominated nutrient regime. We conclude that was not directly toxic to Norway spruce trees at the applied concentrations. However, effects of Mg deficiency were considerably greater in an NH(4) (+)-dominated nutrient regime than in a NO(3) (-)-dominated nutrient regime.

Journal Article↗
PubMed2002

Growth strain in coconut palm trees.

Until recently, growth stress studies have been made only on coniferous and dicotyledonous trees. Growth stress of trees is thought to be initiated in newly formed secondary xylem cells. This stress can accumulate for years and is distributed inside the trunk. Major characteristics of the trunk of monocotyledonous trees include numerous vascular bundles scattered inside the ground tissue and the lack of secondary growth for enlarging the diameter of the trunk. We used the strain gauge method to measure the released growth strain of the monocotyledonous woody palm, coconut (Cocos nucifera L.), and to investigate the surface growth strain of the trunk and central cylinder at different trunk heights. The internal strains of both vertical and leaning trunks were measured and compared with those of coniferous and dicotyledonous trees. We found that tensile stress existed longitudinally on the surface of vertically growing trunks, whereas compression stress was found at the bending position of leaning trunks. Compression stress was found in the outer part of the central cylinder, whereas tensile stress is generally found in the outer part of the trunk in coniferous and dicotyledonous trees. The distribution of strain in the palm trunk is similar to that of compression wood of the leaning trunk of a conifer. Specific gravity was greater in the outer part of the trunk than in the inner part of the trunk. This difference may be related to the distribution of growth stress.

Cocos↗
PubMed1998

A metalloprotease from Xanthomonas campestris that specifically degrades proline/hydroxyproline-rich glycoproteins of the plant extracellular matrix.

Culture supernatants of Xanthomonas campestris pv. campestris contain an enzymic activity capable of degrading gp120, a proline-rich glycoprotein associated with the extracellular matrix of the vascular bundles in petioles of turnip (Brassica campestris). This activity did not reside in any of the three previously characterized proteases of X. campestris pv. campestris that were identified by their action against the model substrate beta-casein. The novel enzyme was purified by ion-exchange and size-exclusion high-performance liquid chromatography (HPLC). The enzyme, which has no activity against beta-casein, is active against some plant glycoproteins of the hydroxyproline-rich class such as extensin from potato and tomato and gpS-3, a glycoprotein induced in B. campestris petioles by wounding. Other hydroxyproline-rich glycoproteins, such as the solanaceous lectins, were not substrates however. Studies of the products released upon degradation of tomato extensin suggested that the degradative mechanism was proteolysis. Inhibitor studies suggested that the enzyme was a zinc-requiring metalloprotease. Extracellular matrix glycoproteins of the proline-rich and hydroxyproline-rich classes have been implicated in plant resistance to microbial attack, hence their degradation by X. campestris pv. campestris may have considerable significance for black rot pathogenesis.

Amino Acid Sequence↗
PubMed2000

Both induction and morphogenesis of cyst nematode feeding cells are mediated by auxin.

Various lines of evidence show that local changes in the auxin concentration are involved in the initiation and directional expansion of syncytia induced by cyst nematodes. Analysis of nematode infections on auxin-insensitive tomato and Arabidopsis mutants revealed various phenotypes ranging from complete inhibition of syncytium development to a decrease in hypertrophy and lateral root formation at the infection site. Specific activation of an auxin-responsive promoter confirmed the role of auxin and pointed at a local accumulation of auxin in developing syncytia Disturbance of auxin gradients by inhibiting polar auxin transport with N-(1-naphthyl)phtalamic acid (NPA) resulted in abnormal feeding cells, which were characterized by extreme galling, massive disordered cell divisions in the cortex, and absence of radial expansion of the syncytium initial toward the vascular bundle. The role of auxin gradients in guiding feeding cell morphogenesis and the cross-talk between auxin and ethylene resulting in a local activation of cell wall degrading enzymes are discussed.

Animals↗
PubMed2000

Structural and expression analysis of uricase mRNA from Lotus japonicus.

Uricase (nodulin-35) cDNA, LjUr, was isolated from nodules of a model legume, Lotus japonicus. LjUr expression was most abundant in nodules, although it was detected in nonsymbiotic tissues as well, particularly in roots. Expression in nodules was detected in uninfected cells, nodule parenchyma, and, more intensely, in vascular bundles. Phylogenetic analysis of uricase sequences from various legumes indicated that uricases of amide- and ureide-transporting legumes form two distinct clades. LjUr is in the cluster of amide-transport legumes even though L. japonicus bears determinate nodules.

Amino Acid Sequence↗
PubMed2000

Regulation of tomato leaf curl viral gene expression in host tissues.

The regulation of expression of the two virion-sense (V1 and V2) and four complementary-sense (C1, C2, C3, and C4) open reading frames (ORFs) of Tomato leaf curl virus (TLCV) was studied in both stably and transiently transformed Nicotiana tabacum tissues with fusions with the beta-glucuronidase (GUS) reporter gene. GUS-expressing transgenic lines were obtained with each of the four complementary-sense gene-GUS fusion constructs and with truncated versions of the virion-sense gene-GUS fusion constructs (V1GUSdeltaC and V2GUSdeltaC) lacking complementary-sense sequences encoding the C1, C2, and C3 ORFs. However, little or no GUS expression was observed in kanamycin-resistant plants transformed with full-length, virion-sense gene constructs (V1GUS and V2GUS) constituting the complete viral genome. In contrast, V1GUS and V2GUS were found to direct high-level GUS expression in transient assays with tobacco protoplasts, suggesting that integration of viral constructs containing functional, complementary-sense genes may lead to repression or deletion of the introduced constructs in transgenic tissues. V2GUS expression in the transient protoplast assay was found to be severely curtailed by specific mutation of the C2 ORF, supporting a role for the C2 protein in transactivation of TLCV virion-sense gene expression. TLCV ORF-GUS constructs displayed distinctive tissue expression patterns in transgenic tobacco plants that could be divided into constitutive (C1, C4, and V2GUSdeltaC), predominantly vascular (C2, C3), or reduced expression in cells associated with the vascular bundles (V1GUSdeltaC). The significance of these results is discussed in terms of current models of gene function and regulation in geminiviruses.

Geminiviridae↗
PubMed2003

Expression of peroxidase-like genes, H2O2 production, and peroxidase activity during the hypersensitive response to Xanthomonas campestris pv. vesicatoria in Capsicum annuum.

Pepper ascorbate peroxidase-like (CAPOA1), thioredoxin peroxidase-like (CAPOT1), and peroxidase-like (CAPO1) clones were isolated from pepper leaves inoculated with avirulent strain Bv5-4a of Xanthomonas campestris pv. vesicatoria. CAPOA1, CAPOT1, and CAPO1 mRNA disappeared 18 to 30 h after the bacterial infection when the hypersensitive response (HR) was visible. In contrast, peroxidase activity reached a peak at 18 h after infection and then declined at 24 and 30 h when H2O2 accumulation level was maximal. These results suggest that the striking accumulation of H2O2 and strong decrease in peroxidase activity during the programmed cell death may be due to the strong suppression of CAPOA1, CAPOT1, and CAPO1 gene expression. Infection by Phytophthora capsici or Colletotricum gloeosporioides also induced the expression of the three putative peroxidase genes in pepper tissues. CAPOA1 mRNAs were in situ localized in phloem areas of vascular bundles in pepper tissues infected by Colletotricum. coccodes, P. capsici, or C. gloeosporioides. Exogenous treatment with H2O2 strongly induced the CAPOA1 and CAPOT1 transcription 1 h after treatment, while the CAPO1 transcripts accumulated 12 h after H2O2 treatment. We suggest that pepper ascorbate peroxidase and thioredoxin peroxidase genes may function as regulators of H2O2 level and total peroxidase activity in the oxidative burst during the HR to incompatible pathogen interaction in pepper plant.

Amino Acid Sequence↗
PubMed2004

cDNA macroarray analysis of gene expression in ineffective nodules induced on the Lotus japonicus sen1 mutant.

The Lotus japonicus sen1 mutant forms ineffective nodules in which development is arrested at the stage of bacterial differentiation into nitrogen-fixing bacteroids. Here, we used cDNA macroarray systems to compare gene expression in ineffective nodules induced on the sen1 mutant with gene expression in wild-type nodules, in order to identify the host plant genes that are involved in nitrogen fixation. Macroarray analysis coupled with Northern blot analysis revealed that the expression of 18 genes was significantly enhanced in ineffective sen1 nodules, whereas the expression of 30 genes was repressed. Many of the enhanced genes encoded hydrolase enzymes, such as cysteine proteinase and asparaginase, that might function in the early senescence of sen1 nodules. By contrast, the repressed genes encoded nodulins, enzymes that are involved in carbon and nitrogen metabolism, membrane transporters, enzymes involved in phytohormone metabolism and secondary metabolism, and regulatory proteins. These proteins might have a role in the establishment of nitrogen fixation. In addition, we discovered two novel genes that encoded glutamate-rich proteins and were localized in the vascular bundles of the nodules. The expression of these genes was repressed in the ineffective nodules, which had lower levels of nitrogenase activity.

Amino Acid Sequence↗
PubMed2001

Fibrous umbilical polyp: a distinct fasciitis-like proliferation of early childhood with a marked male predominance.

Benign fibrous lesions of the umbilicus have not been previously studied in a formal series. Clinical and pathologic findings were reviewed in all patients under age 19 with lesions resected from the umbilical region at Children's Hospital (Boston, MA, USA) during an 8-year period. Fourteen lesions were characterized by a well-circumscribed dome-shaped or pedunculated dermal proliferation of moderately cellular fibrous tissue without significant inflammation. Fibroblastic cells were plump to elongate with abundant pale pink cytoplasm. In a subset of lesions, some cells showed atypia or ganglion cell-like morphology. Collagen ranged from sparse to long narrow bundles. Vascularity was sparse and the lesions were nonencapsulated. Loss of rete ridges and basket-weave hyperkeratosis was common in the overlying epidermis. Immunostaining showed focal staining for muscle-specific actin and desmin in a subset of cases and no staining for cytokeratin, epithelial membrane antigen, CD34, or S-100. Age ranged from 3 to 18 months (mean 9 months, median 8 months). Thirteen (93%) patients were boys. Recurrence was not observed. In conclusion, the "fibrous umbilical polyp" is a distinctive lesion of early childhood with an uncertain pathogenesis. It shows a marked predilection for boys, is not rare, and appears to represent a clinicopathologic entity. Perhaps the umbilicus, a midline defect that is normally filled by dense scar tissue after birth, contains unique fibrogenic factors responsible for the development of this distinct lesion.

Abdominal Neoplasms↗
PubMed1987

Use of computer analysis in flap research.

A computer based analysis of survival of experimental rat skin flaps is presented. The two commonly used experimental flaps, the modified McFarlane dorsal skin flap and the ventral skin flap, are compared. The analysis of the data showed that although the McFarlane flap is random, and the ventral flap based on one epigastric vascular bundle is both axial and random, there was no statistically significant difference in the percent of survival of these flaps. The advantages of the computer based method are discussed.

Animals↗
PubMed1990

Axial flaps for treatment of penis lesions due to granulomas.

Granulomas can result from subcutaneous injection of ointment into the penis to augment its bulk. Rigid, infiltrated granulomatous and scar tissue prevents coitus, often ulcerates, and must be excised. Large segmental or circumferential defects of the penile integument must be covered with soft, pliable skin. We describe our experience with axial skin-fat flaps taken for this purpose from the groin region. There are two well-known vascular bundles, the arteria circumflexa ilium superficialis (ACIS) and arteria epigastrica superficialis (AES). Both were used successfully (the ACIS in 3 patients and the AES in 1) to provide island skin territories sufficient for resurfacing even a completely degloved penis (1 patient) with primary donor wound closure and rapid healing. In addition, a new flap, based on the arteria pudenda externa, was designed and implemented in 1 patient. The donor potential of the groin and lower abdominal region amply meets the requirements for penis reconstruction. Therefore, it is surprising that axial flaps have not yet become broadly accepted.

Adult↗
PubMed1991

The fasciovascular pedicle for revascularization of other tissues.

A fasciovascular pedicle based on the epigastric vessels was developed in a rat model to determine if it could be used as a "universal carrier" to revascularize a new composite flap. The effects of time course, carrier size, and flap ischemia on the revascularization process were studied. A 2.5 x 4-cm or 1 x 4-cm fascial patch pedicled on the vessels was transferred under bipedicled 2.5 x 4-, 6-, or 8-cm abdominal panniculocutaneous flaps. At different time intervals, the flap was raised as an island flap connected only by it vascular bundle and then sutured back in place. The skin perfusion by dermofluorometry and flap survival were both markedly increased on day 5 (p less than 0.001). The wide carrier had a 93% survival area, whereas the narrow carrier had only 71%. The wide carrier induced relatively faster and better revascularization (p less than 0.05). Moderate ischemia promoted revascularization (p less than 0.01). An india ink injection study and histological examination provided visual evidence of revascularization. This fasciovascular pedicle is a promising model for prefabrication of complex new composite flaps and for studying the process of revascularization between the layers. Based on these findings and further investigations, a thin, prefabricated abdominal free flap was successfully transferred for facial resurfacing in humans.

Abdomen↗
PubMed1996

Quantitative analysis of In-111 satumomab pendetide immunoscintigraphy. An aid to visual interpretation of images in patients with suspected carcinomatosis.

The diagnosis of the diffuse intrapertioneal spread of ovarian or colorectal carcinoma (carcinomatosis) can be difficult when based on visual interpretation of immunoscintigraphic images alone. Twenty-nine patients with either colorectal or ovarian cancer were retrospectively evaluated by three technologists for carcinomatosis employing a quantitative analysis technique that compares uptake of In-111 satumomab pendetide (Oncoscint CR/ OV, Cytogen Corp., Princeton, NJ) in a region of interest in the femoral vascular bundle to the uptake in two regions of interest in the lower abdomen, resulting in an uptake ratio (UR). All 29 patients underwent laparotomy after immunoscintigraphy. Of the 29 patients evaluated, 7 had histologically proven carcinomatosis obtained from the laparotomy. Using quantitative analysis, patients who did not have carcinomatosis had a mean uptake ratio of 1.12, and patients with carcinomatosis had a mean uptake ratio of 2.12. The differences between the means of these two groups of patients was statistically significant for all three technologists (P < .05). The results of this study indicate that there is a significant difference in uptake ratios between patients with carcinomatosis and those without it, and that quantitative analysis can be a useful adjunct to visual interpretation.

Abdomen↗
PubMedDate not supplied

Comparative evaluation between external phased array coil at 3 T and endorectal coil at 1.5 T: preliminary results.

OBJECTIVE: The aim of this study was to compare the image quality and the diagnostic accuracy of endorectal coil 1.5 T MRI (erMRI) and phased-array coil 3 T MRI (3-T MRI) in the pretherapeutic staging of prostate cancer. METHODS: Twenty-nine consecutive patients, with pathological proven prostate cancer, have been examined in the same week with both erMRI and 3-T MRI. Two radiologists independently evaluated the image quality focusing on the following points: cancer tissue conspicuity, capsular infiltration and tumor involvement of seminal vesicles, neuro-vascular bundles, and apex. The radiologists assigned to each one of the above findings an image-quality score ranging from 1 to 5 (with 1 meaning "not visible," 2 "poorly visible," 3 "fairly visible," 4 "well visible with some artifacts," and 5 "clearly visible without artifacts".) Afterwards a comparative evaluation of the mean score obtained respectively by erMRI and 3 T MRI was done. Twenty-two of these 29 patients underwent radical prostatectomy. Assuming as gold standard the pathological report from the resected specimen, we compared the diagnostic accuracy of 3TMRI and erMRI in differentiating between tumors confined within the prostate gland (stage<or=T2) and tumors extending through the prostatic capsule (stages T3 and T4). RESULTS: erMRI's image quality was found to be statistically significantly better than 3 T MRI's in evaluating tumor conspicuity, capsular infiltration, and seminal vesicles involvement. On the other hand, considering apex and NVB involvement no statistically significant difference was found between the 2 techniques. On the diagnosis of intracapsular or extracapsular tumor spread 3 T MRI and erMRI showed a comparable performance of sensitivity (75% vs. 83%), specificity (90% vs. 90%), positive predictive value (90% vs. 90%), and negative predictive value (75% vs. 81%). CONCLUSIONS: During preoperative prostate cancer staging, 3 T MRI, despite a slightly worse image quality, can provide comparable diagnostic information to erMRI.

Aged↗
PubMed2001

The fatal wound of Hector, according to a drawing by Peter Paul Rubens designed for tapestry weaving.

According to the Iliad(Chapter XXII, Verses 322-329), Hector, while fighting his last duel, was almost entirely protected by bronze armor, with only a small area "where the clavicle marks the boundary between neck and thorax" exposed. It was precisely into this area, "the shorter way to death," that Achilles thrust his lance. This fatal wound, although covering Hector with blood, allowed the victim to pronounce a few words. In designing the Story of Achilles, his fourth and last series of drawings especially designed for tapestry weaving, Rubens depicted Achilles stabbing Hector near the midline of his neck. There is evidence that Rubens was always well acquainted with the literary sources of his pictures. It is also likely that he became familiar with contemporary editions of the Iliad that were enhanced with commentaries. Realizing that the wound depicted in his original drawing should have prevented Hector from speaking, Rubens altered the scene, then showing the lance piercing the cervical vascular bundle. The careful scrutiny for literary accuracy that was typical of Rubens' artistic behavior did not prevent an additional minor imprecision in the final tapestry. Nevertheless, his outstanding expressive power enabled him to give form to a gigantic baroque representation of the death of Hector in masterly fashion.

Art↗