Tissue-specific expression of tomato Ribonuclease LX during phosphate starvation-induced root growth.

Ribonuclease LX (RNaseLX) from tomato (Solanum lycopersicum L.) belongs to the RNase T2/S-RNase superfamily of plant endoribonucleases and this is a report on the characterization of the RNaseLX gene and its encoded protein as a member of the phosphate starvation response in tomato. RNaseLX gene sequences were cloned by a PCR-assisted approach. RNaseLX promoter sequences contained the conserved binding motif of the transcription factor PHR1 known to mediate phosphate starvation-dependent gene expression. The increase of RNaseLX transcript levels in roots during phosphate starvation correlated with high promoter activity in transgenic plants carrying a PromLX::uidA gene construct and pointed to transcriptional control of RNaseLX expression. Histochemical staining for beta-glucuronidase activity and immunodetection of RNaseLX protein revealed striking RNaseLX expression in main and lateral root tips of phosphate-starved transgenic plants, specifically in epidermal cells, as well as in lateral and adventitious root primordia. Induced RNaseLX expression in roots correlated with stimulated growth and elongation of primary and lateral roots during phosphate deprivation. Phosphate-starvation-induced RNaseLX transcript levels in roots were not modulated by auxin or ethylene. These data indicate that the role of intracellular RNaseLX in the phosphate starvation response is connected with specific RNA turnover processes at the root tip.

Jasmonate biosynthesis in Arabidopsis thaliana--enzymes, products, regulation.

Among the plant hormones jasmonic acid and related derivatives are known to mediate stress responses and several developmental processes. Biosynthesis, regulation, and metabolism of jasmonic acid in Arabidopsis thaliana are reviewed, including properties of mutants of jasmonate biosynthesis. The individual signalling properties of several jasmonates are described.

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.

Molecular cloning of allene oxide cyclase. The enzyme establishing the stereochemistry of octadecanoids and jasmonates.

Allene oxide cyclase (EC ) catalyzes the stereospecific cyclization of an unstable allene oxide to (9S,13S)-12-oxo-(10,15Z)-phytodienoic acid, the ultimate precursor of jasmonic acid. This dimeric enzyme has previously been purified, and two almost identical N-terminal peptides were found, suggesting allene oxide cyclase to be a homodimeric protein. Furthermore, the native protein was N-terminally processed. Using degenerate primers, a polymerase chain reaction fragment could be generated from tomato, which was further used to isolate a full-length cDNA clone of 1 kilobase pair coding for a protein of 245 amino acids with a molecular mass of 26 kDa. Whereas expression of the whole coding region failed to detect allene oxide cyclase activity, a 5'-truncated protein showed high activity, suggesting that additional amino acids impair the enzymatic function. Steric analysis of the 12-oxophytodienoic acid formed by the recombinant enzyme revealed exclusive (>99%) formation of the 9S,13S enantiomer. Exclusive formation of this enantiomer was also found in wounded tomato leaves. Southern analysis and genetic mapping revealed the existence of a single gene for allene oxide cyclase located on chromosome 2 of tomato. Inspection of the N terminus revealed the presence of a chloroplastic transit peptide, and the location of allene oxide cyclase protein in that compartment could be shown by immunohistochemical methods. Concomitant with the jasmonate levels, the accumulation of allene oxide cyclase mRNA was transiently induced after wounding of tomato leaves.

Metabolic profiling of oxylipins upon salicylate treatment in barley leaves--preferential induction of the reductase pathway by salicylate(1).

In barley leaves, 13-lipoxygenases (13-LOXs) are induced by salicylate (SA) and jasmonate. Here, we show by metabolic profiling that upon SA treatment, free linolenic acid and linoleic acid accumulate in a 10:1 ratio reflecting their relative occurrence in leaf tissues. Furthermore, 13-LOX-derived products are formed and specifically directed into the reductase branch of the LOX pathway leading mainly to the accumulation of (13S,9Z,11E,15Z)-13-hydroxy-9, 11,15-octadecatrienoic acid (13-HOT). Under these conditions, no accumulation of other products of the LOX pathway has been found. Moreover, exogenously applied 13-HOT led to PR1b expression suggesting for the time a role of hydroxy polyenoic fatty acid derivatives in plant defense reactions.

Magnetic resonance imaging of Achilles tendon in patients with rheumatoid arthritis.

RATIONALE AND OBJECTIVES: The authors characterize the appearance of the Achilles tendon in patients with rheumatoid arthritis and differentiate this appearance from degenerative tendinopathy in patients with chronic pain of the heel using magnetic resonance (MR) imaging. METHODS: Thirty patients with rheumatoid arthritis and 28 patients with chronic pain of the heel underwent MR imaging of the ankle and foot. Three radiologists independently assessed the MR images with respect to size, shape, and intratendinal signal characteristics of the Achilles tendon. The Achilles tendon was considered abnormal on MR imaging when intratendinous signal alterations or an anteroposterior measurement greater than 8 mm was seen. Physical examination of the Achilles tendons was accomplished in both groups. Operation confirmed the diagnosis of 13 patients in the second group with chronic pain of the heel. RESULTS: The Achilles tendon of 83% of patients with rheumatoid arthritis demonstrated various intratendinous patterns (longitudinal, reticular, nodular) of intermediate signal intensity on all pulse sequences on MR imaging. Ninety percent of patients with rheumatoid tendinopathy showed no enlargement of the anteroposterior diameter of the Achilles tendon. In addition, all patients with rheumatoid arthritis had findings compatible with an inflammation of the retrocalcaneal bursa on MR imaging, whereas none of the patients with tendinopathy associated with chronic heel pain had retrocalcaneal bursitis. All patients, however, had enlargement of the anteroposterior diameter of the Achilles tendon. Seventy-nine percent showed various intratendinous lesions of intermediate signal intensity on all pulse sequences. Twenty-one percent of patients had an enlargement of the Achilles tendon without intratendinous changes. CONCLUSIONS: Rheumatoid tendinopathy can be distinguished from degenerative tendinopathy in patients with chronic pain of the heel with MR imaging. Inflammation of the retrocalcaneal bursa and the absence of enlargement of the tendon combined with the presence of intratendinous signal alterations are characteristic findings of rheumatoid tendinopathy.

[Morphologic characteristics of chondroblastoma. A retrospective study of 56 cases of the Hamburg bone tumor register]. / Morphologische Charakteristika des Chondroblastoms. Eine retrospektive Untersuchung an 56 Fällen des Hamburger Knochentumorregisters.

Representing only about 1% of all primary bone tumors, chondroblastoma constitutes a very rare bone tumor entity. 56 cases of chondroblastoma, that had been collected by the Hamburg Bone Tumor Registry from 1972 to 1995, were examined histologically together with the radiological and clinical findings. In addition immunohistochemistry with antibodies against S 100, PGM1, LCA and the proliferationmarker MIB 1 was performed. The mean age was 20.4 years and male patients being the majority with a gender ratio of 2.7:1. Predominant localisation was the epiphyses of the long bones, although almost 40% of the tumors were located at untypical sites. Usually a well-circumscribed lysis could be seen on plain X-Ray examination, however partial cortical destruction could be observed in one third of the cases. Histologically characteristic was a polygonal cell component with a weblike chonroid matrix, sometimes with a plane-like appearance. 5 cases showed a distinct nuclear polymorphism making a distinction from osteosarcoma difficult. Using immunohistochemistry all tumors except for one showed positive reaction for S 100 protein. Although the histogenesis of chondroblastoma is not completely understood, morphological findings as well as the observed reactivity with the S 100 protein indicate the chondroid origin. No reactivity for PGM 1 (CD 68) or LCA could be detected. All chondroblastoma showed a low rate of proliferation, thereby being distinguishable from high malignant bone tumors. In general chondroblastoma show a benign biological behavior. Different behavior was observed in 2 cases. One relapse located in the pelvis revealed local aggressive growth while in another case in the humerus a malignant transformation had taken place.

[P-glycoprotein expression in osteosarcoma]. / P-Glykoproteinexpression beim Osteosarkom.

One of the mechanisms by which multidrug resistance is mediated, is the mdr1 gene product, P-glycooprotein. Immunohistochemistry was performed for 63 osteosarcomas of 54 patients to investigate P-glycoprotein expression using the monoclonal antibody JSB-1. Most of the patients were children or adolescents who had received treatment under the framework of the Cooperative Osteosarcoma Study Group. In addition P-glycoprotein expression was assayed in five growth plates. Of all cases 68.5% stained positive for P-glycoprotein. Cases that had received chemotherapy showed a higher incidence (80.9%) of positive P-glycoprotein immunostaining than cases that had not received chemotherapy (66.6%). No relation could be established between P-glycoprotein expression and the response to chemotherapy, since the majority of P-glycoprotein positive biopsies showed a good response in the surgical specimen after chemotherapy. Furthermore, 42.9% of P-glycoprotein negative biopsies were classified as non-responders in the later surgical specimen. In addition to P-glycoprotein expression in osteosarcomas positive immunostaining was also detected in osteoblasts, osteocytes, osteoclasts as well as in some chondroblasts. The results indicate that P-glycoprotein expression in osteosarcomas also exists prior to chemotherapy and resembles the phenotype of normal bone tissue. However, the determination of P-glycoprotein by using immunohistochemistry in biopsies of osteosarcomas cannot predict the response to chemotherapy.

[Cell proliferation in bone tumors. Immunohistologic study of Ki-67 protein expression]. / Zellproliferation bei Knochentumoren.

Bone tumors represent a group of tumors of various dignity. In spite of this single tumor entities may display strong morphological resemblance to each other which can in turn result in profound difficulties in differential diagnosis. The biological behaviour of a tumor is mainly determined by its rate of proliferation. In this study the rate of proliferation of 64 bone tumors (30 high-grade central osteosarcomas, 6 low-grade osteosarcomas, 8 giant cell tumors, 8 aneurysmatic bone cysts, 5 osteoidosteomas/osteoblastomas, 7 fibrous dysplasias and 5 cases of a myositis ossificans) were analysed. Immunohistochemistry was performed on paraffin-embedded tissue sections using the MIB-1 monoclonal antibody. MIB-1 recognizes the proliferation-associated Ki-67 protein which is expressed during the active phases of the cell cycle but cannot be detected in senescent cells. Among high-grade central osteosarcomas a significantly higher rate of proliferation (average value 30%) was found in comparison with low-grade osteosarcomas and other benign intraosseous bone tumors. This approach proved to be very useful in the distinction between high-grade and low-grade osteosarcomas as well as bone-forming intraosseous tumors. However distinguishing low-grade osteosarcomas from benign bone tumors by determining only the rate of proliferation was not possible, although interestingly, the proliferative rate of myositis ossificans, a purely reactive lesion, was in the range of the values determined for high-grade osteosarcoma.

[Radiographic changes of the calcaneus in the framework of chronic polyarthritis]. / Radiographische Veränderungen am Fersenbein im Rahmen der chronischen Polyarthritis.

Plain films of the calcaneus of 768 patients with confirmed rheumatoid arthritis were examined retrospectively with reference to inflammatory rheumatic changes. 42 patients (5.5%) showed an erosion of the posterior upper calcaneal margin related to an Achilles bursitis. In three patients there were additional plantar erosions. The Achilles bursitis was bilateral in 50% of cases, particularly in patients in stages 2 and 3 according to Steinbrocker. In the majority of bilateral cases (62%) the size or shape of the lesions was asymmetrical. Our observations indicate that involvement of the os calcis is not uncommon in rheumatoid arthritis; routine examination of this bone would appear to be indicated even in patients without symptoms. Since the defect is unilateral in half the patients, unilateral occurrence of an erosive lesion cannot be regarded as a criterion for a bacterial-inflammatory bursitis. Contrary to the symmetrical involvement of joints in the hands in rheumatoid arthritis, defects in the calcaneus are often unilateral or asymmetrical.

[Sonography of the testes with a new 5 MHz transducer (author's transl)]. / Die Sonographie des Hodens mit einem neuen 5-MHz-Schallkopf.

The article reports on sonography of the testicles with a 5 MHz transducer. Attention is drawn to the outstanding image quality even without a water flowpipe. Sonography offers a diagnostically wide scope in diseases of the testicle, varicocele being the only field where thermography continues to be the method of choice.

[Copper-7 intrauterine device (Gravigard). Report of experience]. / Das Kupfer-7-Intrauterinpessar (Gravigard). Ein Erfahrungsbericht

Within 2 years 258 women aged 16 to 42 years were fitted with a copper-7-IUD (Gravigard, Searle). 45% of these patients were nulliparous women. Follow-up studies were provided in 236 cases in a total of 2717 women-months according to an average time of observation of 11.5 women-months per patient. Altogether there occurred 5 unwanted pregnancies with a Pearl-Index of 2.3. Partial or total expulsion occurred in 27 cases (11%). Fourteen out of 27 expulsions were noticed within the first 2 months after insertion. Removals for medical reasons were requested in 36 cases-in the majority (26 cases) because of bleeding and pain. Thirteen women desired removal of the IUD in order to get either pregnant or sterilized. The continuation rate after 2 years was 73%. The highest number of drop-outs occurred within the first year after insertion (60 cases = 23%) whereas only 4% drop-outs occurred in the 2nd year. It was suggested that the low continuation rate might be partially due to the high number of physicians (19) participating in this study. The most important side effects of the copper-7-IUD in situ were irregular bleeding, intermenstrual pain and discharge. Irregular bleeding and pain decreased markedly after the first year, while slightly prolonged periods persisted in 30 to 50% of all patients. Compared with oral contraceptives copper IUDs hav less severe side effects but less safety at the same time-especially for the younger fertile age group. Therefore they should be offered to young nulliparous women only for a limited period of time.

PIP: Clinical experiences with the copper-7-IUD (Gravigard) in 258 women aged 16-42 years are reported. 45% of the patients were nulliparous women. Follow-up was possible in 236 cases, a total of 2717 women-months ( average of 11.5 woman-months per patient). 5 unwanted pregnancies (Pear l-Index of 2.3) were seen. Partial or total expulsion occurred in 27 cases (11%). 14 of 27 expulsions were noticed within the first 2 months after insertion. Removals for medical reasons were requested in 36 cases; in the majority (26 cases) because of bleeding and pain. 13 women desired removal of the IUD in order to get either pregnant or sterilized. The continuation rate after 2 years was 73%. The highest number of dropouts occurred within the 1st year after insertion (60 cases=23%) whereas only 4% dropouts occurred in the 2nd year. The low continuation rate might be partially due to the high number of physicians (19) participating in this study. The most important side effects of the copper-7-IUD in situ were irregular bleeding, intermenstr ual pain, and discharge. Irregular bleeding and pain decreased markedly after the 1st year, while slightly prolonged periods persisted in 30-50% of all patients. Compared with oral contraceptives, copper IUDs have less severe side effects but also less safety - especially for the younger fertile age group. Therefore they should be offered to young nulliparous women only for a limited period of time.