Plant regeneration from protoplasts of sugar beet (Beta vulgaris)

Mesophyll protoplasts from two of five sugar beet lines tested were regenerated into plants. Mesophyll protoplasts of all lines showed high plating efficiencies up to 4.0% developed hard compact callus, and two of the lines also developed white, soft and friable callus consisting of starch grain-containing cells. Whereas the compact callus never regenerated into plants, the white friable ones frequently developed globular structures, which became green in the light and formed adventitious shoots after cytokinin (BAP or thidiazuron) treatment. Genetic analysis by PCR-fingerprinting and flow cytometry showed uniformity and unchanged ploidy levels in 15 independently regenerated plantlets in line NF. but altered ploidy level (from diploid to triploid) in a regenerated plantlet of clone VRB.     

Somatic hybrids of Datura innoxia Mill.+Datura discolor bernh. and of Datura innoxia Mill.+Datura stramonium L. var. tatula L.

Summary Three sexual generations of the somatic hybrids from Datura innoxia+Datura stramonium (Datura straubii) and from Datura innoxia+Datura discolor (Datura hybrida) were investigated (Schieder, 1978). Self fertility of the somatic hybrids proved to be comparable to that of the parental plant species. The good fertility is attributed to the low number of quadrivalents formed in meiosis I. The growth rate of the somatic hybrids is superior to the parental plant species and also to the autotetraploid somatic hybrids of Datura innoxia. Datura innoxia is the species showing the best growth rate of all species used for the hybridization experiments. In addition, some irregularities in the sexual generations are described.Dedicated to my teacher, Prof. Dr. J. Straub, on the occasion of his 70^th birthday.     

CD34(+)-selected stem cell boost for delayed or insufficient engraftment after allogeneic stem cell transplantation

BACKGROUND: Poor graft function without rejection may occur after stem cell transplantation (SCT). CD34(+) stem cell boost (SCB) can restore marrow function but may induce or exacerbate GvHD. We therefore investigated the feasibility and efficacy of CD34(+)-selected SCB in some patients with poor graft function. We present the results for eight patients (median age 46 years) transplanted initially for myelofibrosis, acute leukemia, myeloma and NHL. Six patients had received HLA-matched and two mismatched grafts (PB, BM; n=5, 3). After a median of 128 days post-transplant, the median leukocyte and platelet counts were, respectively, 2.05/nL and 18/nL. None had achieved platelet counts >50/nL even though donor chimerism was >95% in seven recipients. METHODS: Positive selection of CD34(+) stem cells was performed on a CliniMACS device, observing GMP and achieving a median of 98.5% purity. The patients received a median of 1.7 x 10(6)/kg CD34(+) cells and 2.5 x 10(3)/kg CD3(+) T lymphocytes. RESULTS: Hemograms at days +30, +60 and +90, respectively, showed steadily increasing median leukocyte (2.55, 3.15 and 4.20/nL) and platelet (29, 39 and 95/nL) counts. After a median follow-up of 144 days, five patients remained alive. No patient had developed acute or chronic GvHD. One patient died of leukemic relapse and two others of systemic mycosis. DISCUSSION: These preliminary results point to the possibility of safely improving graft function using CD34(+) positively selected stem cells without necessarily increasing the incidence of GvHD in patients with poor graft function post-SCT. Experience with more patients and longer follow-up should clarify the optimal role for this procedure.     

Comparison of single cell culture derived Solanum tuberosum L. plants and a model for their application in breeding programs

Summary The techniques of microspore and protoplast regeneration starting from dihaploid Solanum tuberosum plants has been improved to such an extent that the production of more than 2000 microspore derived A₁ plant lines and of several hundred protoplast derived plantlets has become possible. Further, from the dihaploid Solanum species S. phureja the regeneration of microspores to plants, and from the species S. infundibuliforme, S. sparsipilum and S. tarijense the regeneration of protoplasts to calluses, has been achieved. The plants descending from the two single cell culture systems are compared with reference to phenotypic markers and economic qualities. Some principles characteristic for either microspore or protoplast derived plants are examined and their significance is discussed. The results are compiled into an extended analytical synthetic breeding scheme based on a stepwise reduction of the autotetraploid to the monohaploid level and a subsequent controlled combination to a new synthetic completely heterozygous tetraploid potato.     

Community Life and Discourses among Fiji Islanders in Kantō, Japan

This article examines how Fiji Islanders of diverse ethnic backgrounds living in Japan's Kantō area reflect on and constitute community life in the diaspora. While they occasionally refer to the ‘community’ and speak about its social value, get-togethers of significant numbers occur infrequently. Ultimately, a Fijian-centred community is virtually absent in the everyday lives of Japan-based Fiji Islanders. Based on twelve months of ethnographic fieldwork in the Tokyo Metropolis and its neighbouring prefectures, this contribution suggests that for Fiji Islanders in Kantō, talking about ‘community’ serves two particular purposes: on the one hand community discourses create an emotional bond, both among the migrants and between the migrants and their place of origin. At the same time, discourses on the relevance of the community without undergoing efforts to maintain it, serve as strategies of navigating self and belonging in a critical and reflexive way. As migrants’ social lives are complex and shaped by numerous economic, spatial, and individual disjunctures, Kantō Fiji Islanders contextually configure and extend their social relations with regard to their socio-cultural heritage, their place of residence in Japan, their gaikokujin (foreigner) status, and their life-work cycles.     

Thidiazuron-induced plant regeneration from protoplasts of Vicia faba cv. Mythos

Summary Protoplasts of 10 cultivars of V. faba were isolated from etiolated shoot-tips and tested for their regeneration capacity. After purification, protoplasts were embedded in sodium alginate and cultivated in the medium of Kao and Michayluk (1975) containing 0.5 mg·1^–1 of each 2,4-dichlorophenoxyacetic acid, naphthylacetic acid and 6-benzylaminopurine. Depending on cultivar, division frequencies of up to 40% were obtained. Six weeks after embedding, protoplast-derived calluses were transferred to Gelrite-solidified media with different combinations of growth regulators. A two step protocol (auxin high/low) was tested for its ability to induce somatic embryogenesis. The formation of globular structures was observed, but no embryo formation could be achieved. In contrast, cultivation of protocalluses on medium supplemented with thidiazuron resulted in shoot development in cultivar Mythos. To generate mature plants, the shoots were grafted onto young seedlings. In order to optimize the in vitro-conditions, different concentrations of thidiazuron alone or in combination with naphthylacetic acid were tested, showing that an increase of thidiazuron and the addition of naphthylacetic acid positively affects both the viability of protocalluses and the regeneration frequency.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - BA 5-benzylaminopurine - GA₃ gibberellic acid - IBA indole-3-butyric acid - Kin kinetin - KM Kao and Michayluk - MS Murashige and Skoog - NAA naphthylacetic acid - TDZ thidiazuron - Zea zeatin     

Novel 'homeotic' CMS patterns generated in Nicotiana via cybridization with Hyoscyamus and Scopolia

Cytoplasmic hybrids (cybrids) that contain nuclear genetic materialfrom Nicotiana tabacum and cytoplasms from Hyoscyamus nigeror Scopolia carniolica were constructed by protoplast fusions.Both types of hybrids exhibited cytoplasmic male sterility (CMS).Furthermore, unusual floral morphogenesis marked by ‘greenflowers’ deprived of corolla and stamens occurred in themajority of the lines. Backcrosses of these plants with wild-typetobacco demonstrated a maternal inheritance of the ‘greenflower’ trait. After repeated transfer of cytoplasm (‘donor-recipientfusion’) from cytoplasmic hybrid N. tabacum (+H. niger)to albino plastome mutant N. tabacum DSR A15, male sterile tobaccoplants with two types of flowers were recovered (‘greenflowers’ and corolla-containing flowers with transformedstamens). RFLP analysis confirmed that N. tabacum (+ H. niger)and N. tabacum (+S. carniollca) as well as their sexual progeniescontained plastids from H. niger and S. carniolica, respectively.Mitochondrial DNA within the hybrids N. tabacum (+H. niger)originated from H. niger, but was obviously altered. Repeatedparasexual transmission, cybrids in the combination of N. tabacum+N.tabacum (+H. niger), reflected similar characteristics. Cybrids,N. tabacum (+S. carniolica) and their sexual progeny, whichresulted after pollination with wild-type tobacco, containeda modified mtDNA generally originating from tobacco. Furtherhistological analysis established the dramatic difference inthe composition of ‘green flowers’ and flowers ofwild-type tobacco. Therefore, the construction of tobacco cybridswith foreign cytoplasms provides a functional method for thede nova generation of alternative CMS types. Key words: Nicotiana, Hyoscyamus, Scopolia, cybrids, CMS, homeotic patterns     

Induced mutants from dihaploid potatoes after pollen mother cell treatment

Summary Microspore mother cells of dihaploid Solanum tuberosum plants were mutagenically treated during the stage of meiosis. Mutagenesis was performed either by irradiation with x- or -rays or by the application of nitrosomethylurethane or methylnitronitrosoguanidine. Then, by use of the anther culture technique, 913 functional plants and 442 untreated control plants were regenerated. From the exposed plants seven distinct mutants could be isolated, predominantly chlorophyll deficient lines, while from the controls no clear-cut mutants arose. One mutant turned out to be photomorphogenetic in addition to having a chlorophyll defect. In addition to the production of mutants the treatments significantly increased the frequency of multicellular structure formation from microspores.     

Transient and stable expression of marker genes in cotransformedPetunia protoplasts in relation to X-ray and UV-irradiation

Irradiation of protoplasts with X-rays or ultraviolet light does not seem to influence the level of transient expression of foreign DNA inPetunia protoplasts, whereas the number of stably transformed colonies is significantly raised. This may indicate that irradiation influences integration and/or the expression of marker genes and does not result in enhanced uptake rates of plasmids into protoplasts and cell nuclei. Co-transformation with plasmids carrying a gene for kanamycin resistance (neomycin phosphotransferase II) and a gene for hygromycin resistance (hygromycin phosphotransferase) revealed that the cotransformation rates were not stimulated by irradiation when measuring expression. Twenty-five kanamycin resistant but hygromycin sensitive colonies were examined with Southern or slot blotting and all were found to contain the coding sequence for the hygromycinphosphotransferase gene in their genomes. No obvious differences regarding copy number of integrated genes were observed when comparing transformed colonies derived from irradiated and non-irradiated protoplasts.