AIM:Long-term anchorage of foreign material in vital bone has proven to be the main problem in hip arthroplasty. Bone cement, a material for filling and fitting, allows an excellent solution for older people. Many failures have been blamed on the use of polymethylmethacrylate in younger patients. In our opinion, modelling a stem to the individual anatomic needs of younger patients and to implant it without cement but with a stable press-fit is a good way to transmit stress harmoniously from the prosthesis to the bone and to obtain a long-lasting function. This individual hip stem is now available in the third generation under the name Adaptiva(R). We would like to present our first results.METHOD:Between October 1993 and September 1995 150 individual hip prosthesis of the Adaptiva(R) type have been implanted. In the average the patients were 53,2 years old. The average time of follow-up was 19.9 (12 to 44) months.RESULTS:The Merle d'Aubigné score showed excellent absolute and relative results for pain, mobility and ability to walk. No aseptic loosening of the stem occurred.CONCLUSION:Our early results are promising, but we have to wait for the long-term results, which are part of a current study.

Aim: Long-term anchorage of foreign material in vital bone has proven to be the main problem in hip arthroplasty. Bone cement, a material for filling and fitting, allows an excellent solution for older people. Many failures have been blamed on the use of polymethylmethacrylate in younger patients. In our opinion, modelling a stem to the individual anatomic needs of younger patients and to implant it without cement but with a stable press-fit is a good way to transmit stress harmoniously from the prosthesis to the bone and to obtain a long-lasting function. This individual hip stem is now available in the third generation under the name Adaptiva. We would like to present our first results. Method: Between October 1993 and September 1995 150 individual hip prosthesis of the Adaptiva type have been implanted. In the average the patients were 53,2 years old. The average time of followup was 19.9 (12 to 44) months. Results: The Merle d'Aubigne score showed excellent absolute and relative results for pain, mobility and ability to walk. No aseptic loosening of the stem occurred. Conclusion: Our early results are promising, but we have to wait for the long-term results, which are part of a current study.

SF21 was originally described as a pollen- and pistil-expressed protein from sunflower and tobacco. In pistils excised from these species, transcripts were detected in the stigma and in the transmitting tissue where they accumulated in an ovary-oriented increasing concentration gradient. We studied the cellular localization of the SF21 protein during various stages of pistil development as well as in pollen grains of tobacco and sunflower. Here we demonstrate that in young tobacco pistils (from stage 2 onwards) this protein is expressed exclusively in the papillae and secretory cells of the stigma where it is located first in the nucleus and subsequently also in the cytoplasm. Only several stages later (stage 10) does it appear in the transmitting tissue cells of the style where it exhibits a similar, but temporally-delayed, dual nuclear and cytoplasmic localization pattern. SF21 is no longer present in either the stigma or style at the time of pollination, indicating that it is not directly involved in the pollination process. In tobacco pollen grains, SF21 appears just prior to pollen germination and localizes to the apical region of growing pollen tubes, suggesting a possible role in pollen tube growth. This temporal and spatial expression pattern as well as the dual nuclear/cytoplasmic localization suggest that SF21 could be involved in several molecular functions during pistil development and pollen tube growth.

The Arabidopsis genome contains three distinct genes encoding sterol-C24-methyltransferases (SMTs) involved in sterol biosynthesis. The expression of one of them, STEROL METHYLTRANSFERASE 2;1, was modulated in 35S::SMT2;1 Arabidopsis in order to study its physiological function. Plants overexpressing the transgene accumulate sitosterol, a 24-ethylsterol which is thought to be the typical plant membrane reinforcer, at the expense of campesterol. These plants displayed a reduced stature and growth that could be restored by brassinosteroid treatment. Plants showing co-suppression of SMT2;1 were characterized by a predominant 24-methylsterol biosynthetic pathway leading to a high campesterol content and a depletion in sitosterol. Pleiotropic effects on development such as reduced growth, increased branching, and low fertility of high-campesterol plants were not modified by exogenous brassinosteroids, indicating specific sterol requirements to promote normal development. Thus SMT2;? has a crucial role in balancing the ratio of campesterol to sitosterol in order to fit both growth requirements and membrane integrity.

Biology of the CellVolume 90, Issue 3 p. 282-282 Spatial regulation of helianthinin gene expression in the sunflower embryo J. Molinier, J. Molinier Institut de Biologie Moléculaire des Plantes, CNRS et Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg cedex, FranceSearch for more papers by this authorF. Charrière, F. Charrière Institut de Biologie Moléculaire des Plantes, CNRS et Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg cedex, FranceSearch for more papers by this authorR. Bronner, R. Bronner Institut de Biologie Moléculaire des Plantes, CNRS et Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg cedex, FranceSearch for more papers by this authorG. Hane, G. Hane Institut de Biologie Moléculaire des Plantes, CNRS et Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg cedex, FranceSearch for more papers by this author J. Molinier, J. Molinier Institut de Biologie Moléculaire des Plantes, CNRS et Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg cedex, FranceSearch for more papers by this authorF. Charrière, F. Charrière Institut de Biologie Moléculaire des Plantes, CNRS et Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg cedex, FranceSearch for more papers by this authorR. Bronner, R. Bronner Institut de Biologie Moléculaire des Plantes, CNRS et Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg cedex, FranceSearch for more papers by this authorG. Hane, G. Hane Institut de Biologie Moléculaire des Plantes, CNRS et Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg cedex, FranceSearch for more papers by this author First published: 01 February 2012 https://doi.org/10.1016/S0248-4900(98)80053-1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume90, Issue3June 1998Pages 282-282 RelatedInformation

Abstract: Somatic embryos and adventitious shoots can be induced simultaneously on immature zygotic embryos of sunflower, their relative distribution on the explant being constant but their relative number depending on the sucrose concentration of the culture medium. We show here that the cells at the origin of both types of structures are competent for either development and express this potential as a function of their position relative to the medium. Two zones, inductive for somatic embryos or adventitious shoots, have been established under the influence of the culture medium. The precision of their localisation is demonstrated by the existence of tissue chimeras which also indicate the presence of diffusible signal(s) responsible for the determination of cellular identity. We have further determined that commitment to the organogenic pathway occurred very rapidly, i.e. within 12 h after the onset of the culture. A synthetic model is presented in which we suggest a possible sequence of key events involved in the morphogenic processes.

Epiphyllous buds developed on leaves of shoots derived from in vitro cultured apices of sunflower (Helianthus annuus L.) seedlings. This phenomenon was shown to be cytokinin-dependent but only occurred when the cytokinin was supplied via the cultured apices producing the leaf-bearing shoots. A 1-day exposure of apices to cytokinin was sufficient for epiphyllous bud induction, although an exposure of more than 4 days yielded maximal shoot development frequencies from these buds. Preculture of complete donor seedlings on cytokinin-supplemented media and subsequent culture of excised leaves on hormone-free medium was insufficient to induce epiphyllous bud formation. Buds became macroscopically visible after 9–11 days. At this time, epiphyllous buds consisted of a functional meristem producing true shoots which were capable of seed production. The meristems were formed by a multicellular process originating from subepidermal layers on the adaxial leaf side. The role of cytokinin and other potential factors in the induction of epiphyllous buds on sunflower leaves is discussed.

According to the hormonal conditions, after one month of culture shoots or somatic embryos could be obtained from leaf explants ofHelianthus smithii. Well-shaped embryos developed on media containing a combination of auxin and cytokinin, while on media containing only cytokinin shoots were observed. The primary leaves of these shoots resembled cotyledons. A detailed histological study of the regeneration process on three media, containing only cytokinin or auxin, or a combination of both, allowed the origin and development of the observed structures to be determined. All three conditions induced somatic embryos, which then developed differently and, within one month, finally gave rise to the two types of structures which were initially observed.

Sunflower plants (inbred line 47 302 bcd) can be regenerated from hypocotyl protoplasts. During the regeneration process, we have observed two kinds of calli differing by their cell types. Morphogenic calli, from which regeneration of shoots was possible, were characterized by the presence of starch granules, and clusters of small meristematic-like cells. Non-morphogenic calli did not contain either meristematic-like cells or starch, but a varying proportion of the typical callus cells at more or less advanced stages of degeneration. We have analyzed samples from each step of protoplast culture for the presence of starch, i.e. the initial protoplast population, micro- and macro-colonies and calli. On each step, only a small percentage of the structures contained starch. These results are discussed in view of a possible origin of these morphogenic calli from particular cell types existing in the donor tissue, i.e. stomatal guard cells and endodermis cells.

A novel pistil- and pollen-expressed gene (sf21) encoding a 352 amino acid long polypeptide was isolated by differential screening of a floral cDNA library from sunflower (Helianthus annuus L.) and characterized. The deduced polypeptide is structurally related to the human protein RTP and the mouse protein Ndr1. It also shares significant sequence homology with an unidentified polypeptide from human cerebellum (N-terminus) and with the ligand binding region of the vertebrate inositol 1,4,5 trisphosphate (IP3) receptor (C-terminus). The sf21 gene is expressed in young and mature florets of an open inflorescence but not at the floral bud stage. In the sunflower pistil, expression is restricted to the transmitting tissue and the phloem cells. The same location of expression, with an increasing concentration gradient of SF21 transcripts towards the ovule, is observed during specific stages in tobacco pistils. The transcripts gradually disappear as the pollen tubes grow through the transmitting tissue. These observations suggest that the protein acts in pollen-pistil interactions.

One genomic (SF15G) and four different cDNA clones (SF15-49, SF15-2, SF15-3 and SF15-45) expressed in the young green closed sunflower (Helianthus annuus L.) inflorescence were isolated and characterized. Northern blot analysis revealed temporal regulation of the sf15 gene family: the transcripts accumulate transiently between stage 1 and 4 of floret development and disappear before the florets reach maturity. The SF15 mRNAs were undetectable in male-sterile sunflower plants. In situ hybridization experiments showed that expression of the SF15 transcripts occurs in the anther epidermal cell layer as well as in immature pollen, in the corollar tissue, and in the papillar cells of the stigma. The sf15 gene encodes a putative polypeptide of 280 amino acids with a molecular weight of 31.7 kDa. The five sunflower SF15 proteins are highly homologous to each other (82–99% nucleotide and amino acid sequence identity). They are basic (isoelectric point of 9.6) and have a potential N-terminal signal peptide, indicating that they may enter the secretory pathway. The presence of a short hydrophobic C-terminal domain in the protein encoded by the genomic sequence but not in the proteins encoded by the cDNAs suggests an extracellular as well as a vacuolar location for this family of proteins. Southern blot analysis shows that in sunflower the sf15 gene exists as a family of genes with approximately six to eight family members. The sf15 gene is also present in the maize, tomato and cabbage genomes.

Both organogenesis and somatic embryogenesis can be induced in 6-mm immature zygotic embryos of sunflower, depending on the sucrose concentration of the induction medium; shoots were induced at a concentration of 3%, while embryos were formed at 12%. Both morphogenic events were direct, without intervening callus formation, and occurred in the lower third of the hypocotyl. Shoots and somatic embryos had a multicellular origin. They were initiated by periclinal cell divisions in the epidermis and the outer cell layers of the hypocotyl cortex within the 1st day of culture. The two types of morphogenic events could already be distinguished on the 2nd day of culture, in that proteins and lipids started to accumulate in the somatic embryogenic tissues but not in the shoot tissues. This system provides a model that can be used to study early biochemical and molecular events taking place in explants at the onset of organogenesis and somatic embryogenesis, as these two processes occur in a predictable manner and location. Key words: cytology, organogenesis, somatic embryogenesis, storage products, sucrose concentration, sunflower.

The study of sterol overproduction in tissues of LAB 1-4 mutant tobacco (Nicotiana tabacum L. cv Xanthi) (P. Maillot-Vernier, H. Schaller, P. Benveniste, G. Belliard [1989] Biochem Biophys Res Commun 165: 125-130) over several generations showed that the overproduction phenotype is stable in calli, with a 10-fold stimulation of sterol content when compared with wild-type calli. However, leaves of LAB 1-4 plants obtained after two steps of self-fertilization were characterized by a mere 3-fold stimulation, whereas calli obtained from these plants retained a typical sterol-overproducing mutant phenotype (i.e. a 10-fold increase of sterol content). These results suggest that the expression of the LAB 1-4 phenotype is dependent on the differentiation state of cells. Most of the sterols accumulating in the mutant tissues were present as steryl-esters, which were minor species in wild-type tissues. Subcellular fractionation showed that in both mutant and wild-type tissues, free sterols were associated mainly with microsomal membranes. In contrast, the bulk of steryl-esters present in mutant tissues was found in the soluble fraction of cells. Numerous lipid droplets were detected in the hyaloplasm of LAB 1-4 cells by cytochemical and cytological techniques. After isolation, these lipid granules were shown to contain steryl-esters. These results show that the overproduced sterols of mutant tissues accumulate as steryl-esters in hyaloplasmic bodies. The esterification process thus allows regulation of the amount of free sterols in membranes by subcellular compartmentation.

Tungsten and gold particles, coated with plasmid DNA harboring the beta-glucuronidase (GUS) and neomycin phosphotransferase II (npt-II) genes, were delivered into tobacco primary leaves and suspension-cultured cells of maize using the helium particle inflow gun. Cell viability and particle localization were determined 1 and 2 days after bombardment. Of the counted particles, 7-10% penetrated into or through the epidermis. Blue spots on tobacco leaves appeared as a blue area around a single, densely stained particle-containing central cell. DNA-coated gold particles provoked smaller spots with less diffusion and gave rise to more individual events than tungsten particles. In more than 90% of the GUS-positive epidermal and mesophyll cells, a particle was detectable within their nucleus. Two days after bombardment, viability had decreased to 1-2% in particle-containing cells.Penetration of a cell by a particle was accompanied by callose formation in the wound area. Dead suspension culture cells of maize without callose formation but containing particles were detected just 1 h postbombardment. Living cells with callose spots appeared more frequently after bombardment with tungsten than gold. As in tobacco, GUS expression was limited to those cells containing a particle in their nucleus, and the number of particle-containing, viable cells was low after 48 h.The frequency of stable expression events was compared to the number of surviving tobacco leaf cells. On average, four kanamycin-resistant calli or plantlets were recovered per bombarded dish, of which approximately 50% were also GUS-positive. This corresponds to a stable-to-transient ratio of approximately 0.8%, and is similar to the number of particle-containing cells surviving after 48 h.

Transient expression of the uidA gene, coding for β-glucuronidase (GUS) and driven by different promoters, has been induced in sunflower cotyledonary explants and immature zygotic embryos of different developmental stages using two particle delivery systems. Explants were evaluated for expression of β-glucuronidase activity 3 days, 2, and 4 weeks post bombardment. Immature embryos were more suitable for transformation than cotyledons derived from mature seeds. The highest level of transient GUS expression after 3 and 14 days was obtained with embryos (≤1.5 mm) precultured for 3 days in the presence of NAA and BAP. After 2 and 4 weeks of culture, increased GUS activities were determined following bombardment with plasmids harboring a doubled CaMV 35S and a stress inducible promoter, respectively. In cotyledons, GUS-expressing cells were mostly observed in the epidermal layer, while in immature embryos they were located between the epidermis and the fourth mesophyll layer. The performance of the two biolistic equipments was comparable. Under any condition, GUS expression declined with increasing culture time.

ABSTRACTThe regeneration process in order to locate cells competent for morphogenesis was studied. This information should be valuable also for the production of transgenic plants. In several plant species, cotyledons exhibit a very high morphogenic potential and fertile plants can be recovered at high frequencies. Such systems are useful to produce transgenic plants, provided that the cells involved in regeneration can be stably transformed. Knittel et. al. (1) have developed a protocol for plant regeneration based on in vitro culture of cotyledons of young seedlings. ABSTRACTThe regeneration process in order to locale cells competent for morphogenesis was studied. This information should be valuable also for the production of transgenic plants. In several plant species, cotyledons exhibit a very high morphogenic potential and fertile plants can he recovered at high frequencies. Such systems are useful to produce transgenic plants, provided that the cells involved in regeneration can be stably transforme...