Induction of androgenesis and production of haploid embryos in anther cultures of borage (Borago officinalis L.)

[EN] Borage (Borago officinalis L.) is an important medicinal plant with different culinary, pharmaceutical and industrial properties. Unfortunately, there are no published reports on the establishment of protocols to produce DHs in this species up to now. In this work, we show for the first time the induction of borage microspores to become embryogenic calli, from which haploid embryos are produced. In addition, we evaluated the effect of using different flower bud sizes, carbon sources, concentrations of 2,4-D and BAP, cold (4 A degrees C) pretreatments and heat shock treatments. Production of total calli, embryogenic calli and callus-derived embryos was differently affected by the different parameters studied. Our results showed that the use of 5-7 mm-long flower buds, a cold (4 A degrees C) pretreatment during 4 days, a 32 A degrees C heat shock for 3 days, and the addition of 3 % maltose and 2 mgl(-1) 2,4-D and 1 mgl(-1) BAP to the culture medium, was beneficial for embryo production. Overall, this work demonstrates that DH technology is possible in borage, and opens the door for future improvements needed to finally obtain borage DH plants.Eshaghi, ZC.; Abdollahi, MR.; Moosavi, SS.; Deljou, A.; Seguí-Simarro, JM. (2015). Induction of androgenesis and production of haploid embryos in anther cultures of borage (Borago officinalis L.). Plant Cell, Tissue and Organ Culture. 122:321-329. doi:10.1007/s11240-015-0768-5S321329122Abdollahi MR, Moieni A, Javaran MJ (2004) Interactive effects of shock and culture density on embryo induction in isolated microspore culture of Brassica napus L. cv. 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In: Mazza G (ed) Functional foods, biochemical and processing aspects. Technomic Publ Co. Inc, Lancaster, pp 265–291Ozkum D, Tipirdamaz R (2002) The effects of cold treatment and charcoal on the in vitro androgenesis of pepper (Capsicum annuum L.). Turk J Bot 26:131–139Parra-Vega V, González-García B, Seguí-Simarro JM (2013a) Morphological markers to correlate bud and anther development with microsporogenesis and microgametogenesis in pepper (Capsicum annuum L.). Acta Physiol Plant 35:627–633Parra-Vega V, Renau-Morata B, Sifres A, Seguí-Simarro JM (2013b) Stress treatments and in vitro culture conditions influence microspore embryogenesis and growth of callus from anther walls of sweet pepper (Capsicum annuum L.). Plant Cell Tissue Organ Cult 112:353–360Raquin C (1983) Utilization of different sugars as carbon sources for in vitro cultures of Petuina. 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Archon Books, Hamden, CTSkrzypek E, Czyczyło-Mysza I, Marcińska I, Wędzony M (2008) Prospects of androgenetic induction in Lupinus spp. Plant Cell Tissue Organ Cult 94(2):131–137Snape JW (1989) Doubled haploid breeding: theoretical basis and practical applications. In: Mujeeb-Kazi A, Sitch LA (eds) Review of advances in plant biotechnology, 1985–1988: 2nd international symposium genetic manipulation in crops. Mexico and Manila, CIMMYT and IRRI, pp 19–30Tipirdamaz R, Ellialtioğlu Ş (1998) The effects of cold treatments and activated charcoal on ABA contents of anthers and in vitro androgenesis in eggplant (Solanum melongena L.). In: Tsekos I, Moustakas M (eds) Progress in botanical research, Proceedings of the 1st Balkan botanical congress. Kluwer Academic Publishers, The NetherlandsVagera J, Havranek P (1985) In vitro induction of androgenesis in Capsicum annuum L. and its genetic aspests. 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Using Classical Population Genetics Tools with Heterochroneous Data: Time Matters!

BACKGROUND:New polymorphism datasets from heterochroneous data have arisen thanks to recent advances in experimental and microbial molecular evolution, and the sequencing of ancient DNA (aDNA). However, classical tools for population genetics analyses do not take into account heterochrony between subsets, despite potential bias on neutrality and population structure tests. Here, we characterize the extent of such possible biases using serial coalescent simulations. METHODOLOGY/PRINCIPAL FINDINGS:We first use a coalescent framework to generate datasets assuming no or different levels of heterochrony and contrast most classical population genetic statistics. We show that even weak levels of heterochrony ( approximately 10% of the average depth of a standard population tree) affect the distribution of polymorphism substantially, leading to overestimate the level of polymorphism theta, to star like trees, with an excess of rare mutations and a deficit of linkage disequilibrium, which are the hallmark of e.g. population expansion (possibly after a drastic bottleneck). Substantial departures of the tests are detected in the opposite direction for more heterochroneous and equilibrated datasets, with balanced trees mimicking in particular population contraction, balancing selection, and population differentiation. We therefore introduce simple corrections to classical estimators of polymorphism and of the genetic distance between populations, in order to remove heterochrony-driven bias. Finally, we show that these effects do occur on real aDNA datasets, taking advantage of the currently available sequence data for Cave Bears (Ursus spelaeus), for which large mtDNA haplotypes have been reported over a substantial time period (22-130 thousand years ago (KYA)). CONCLUSIONS/SIGNIFICANCE:Considering serial sampling changed the conclusion of several tests, indicating that neglecting heterochrony could provide significant support for false past history of populations and inappropriate conservation decisions. We therefore argue for systematically considering heterochroneous models when analyzing heterochroneous samples covering a large time scale

Second malignant neoplasms after a first cancer in childhood: temporal pattern of risk according to type of treatment

The variation in the risk of solid second malignant neoplasms (SMN) with time since first cancer during childhood has been previously reported. However, no study has been performed that controls for the distribution of radiation dose and the aggressiveness of past chemotherapy, which could be responsible for the observed temporal variation of the risk. The purpose of this study was to investigate the influence of the treatment on the long-term pattern of the incidence of solid SMN after a first cancer in childhood. We studied a cohort of 4400 patients from eight centres in France and the UK. Patients had to be alive 3 years or more after a first cancer treated before the age of 17 years and before the end of 1985. For each patient in the cohort, the complete clinical, chemotherapy and radiotherapy history was recorded. For each patient who had received external radiotherapy, the dose of radiation received by 151 sites of the body were estimated. After a mean follow-up of 15 years, 113 children developed a solid SMN, compared to 12.3 expected from general population rates. A similar distribution pattern was observed among the 1045 patients treated with radiotherapy alone and the 2064 patients treated with radiotherapy plus chemotherapy; the relative risk, but not the excess absolute risk, of solid SMN decreased with time after first treatment; the excess absolute risk increased during a period of at least 30 years after the first cancer. This pattern remained after controlling for chemotherapy and for the average dose of radiation to the major sites of SMN. It also remained when excluding patients with a first cancer type or an associated syndrome known to predispose to SMN. When compared with radiotherapy alone, the addition of chemotherapy increases the risk of solid SMN after a first cancer in childhood, but does not significantly modify the variation of this risk during the time after the first cancer. © 1999 Cancer Research Campaig

Dose finding and O6-alkylguanine-DNA alkyltransferase study of cisplatin combined with temozolomide in paediatric solid malignancies

Cisplatin may have additive activity with temozolomide due to ablation of the DNA repair protein O6-alkylguanine-DNA alkyltransferase (MGMT). This phase I/II study determined recommended combination doses using the Continual Reassessment Method, toxicities and antitumour activity in paediatric patients, and evaluated MGMT in peripheral blood mononuclear cells (PBMCs) in order to correlate with haematological toxicity. In total, 39 patients with refractory or recurrent solid tumours (median age ∼13 years; 14 pretreated with high-dose chemotherapy, craniospinal irradiation, or having bone marrow involvement) were treated with cisplatin, followed the next day by oral temozolomide for 5 days every 4 weeks at dose levels 80 mg m−2/150 mg m−2 day−1, 80/200, and 100/200, respectively. A total of 38 patients receiving 113 cycles (median 2, range 1–7) were evaluable for toxicity. Dose-limiting toxicity was haematological in all but one case. Treatment-related toxicities were thrombocytopenia, neutropenia, nausea-vomiting, asthenia. Hearing loss was experienced in five patients with prior irradiation to the brain stem or posterior fossa. Partial responses were observed in two malignant glioma, one brain stem glioma, and two neuroblastoma. Median MGMT activity in PBMCs decreased after 5 days of temozolomide treatment: low MGMT activity correlated with increased severity of thrombocytopenia. Cisplatin–temozolomide combinations are well tolerated without additional toxicity to single-agent treatments; the recommended phase II dosage is 80 mg m−2 cisplatin and 150 mg m−2 × 5 temozolomide in heavily treated, and 200 mg m−2 × 5 temozolomide in less-heavily pretreated children

An improved method for resquing zygotic embryos of Pelargonium X hortorum Bayley

International audienc

Air like 38Ar/36Ar in the mantle: implications for the nature of the parent bodies of the Earth

International audienceThe `'stable'' 20Ne/22Ne ratios in mantle-derived samples clearly differ from the atmospheric ratio. 20Ne/22Ne in oceanic basalts show obviously a solar origin (>12). Nevertheless, the mantle ratio (e.g. not contaminated by air) is not precisely determined. No mantle-derived samples have precise 20Ne/22Ne ratios above 13.0±0.2 (1σ). Two models are generally discussed to explain this solar origin. One is to dissolve solar wind gases in a previously degassed magma ocean. The other is that the mantle value is similar to the so-called Neon B (12.5 ± 0.2; (1σ)), which corresponds to mixing between the `'normal'' solar wind and solar energetic particles (SEP). This ratio is notably observed in gas rich meteorites, which are breccias irradiated in an early phase of the planetary accretion. The knowledge of the isotopic composition of rare gases in the mantle has important implications for the model of volatile acquisition on Earth. Some mantle-derived samples show 38Ar/36Ar ratios different from the atmosphere ratio and trend to the solar-wind isotopic composition. These results were challenged and an air like argon composition in the mantle has been suggested. As 40Ar signal is up to one million times higher than the 38Ar, we can suspect an influence of the 40Ar signal on the 38Ar base line (tail effect) during mass spectrometer analyses, giving low 38Ar/36Ar. Moreover, step heating appears to fractionate argon isotopes. We have performed a complete study of He, Ne and Ar in MORB and OIB in order to constrain the argon isotopic composition of the mantle. Using samples that have suffered only little air contamination and degassing, analyzed by crushing with a new analytical procedure, we show that the mantle 38Ar/36Ar is not different from the atmospheric ratio even for 20Ne/22Ne higher than 12.5. Starting from isotopic compositions close to the solar wind for both Ne and Ar, one may suppose than atmospheric argon was recycled within the mantle without neon during subduction. However, the 129Xe anomalies observed in mantle-derived sample suggest that the subduction of argon is probably not the source of the atmospheric 38Ar/36Ar in the mantle. The simplest explanation is that the parent bodies of the Earth were irradiated by a solar wind during the planetary accretion (T Tauri ?), giving these specific neon and argon isotopic compositions to the Earth (gas rich meteorite show air-like argon associated to neon B)

Rare gas systematics in the Indian Ocean mantle: the DUPAL anomaly

International audienceThe "DUPAL" anomaly, defined by S. Hart, located in the Indian Ocean and in a part of the South Atlantic is considered to result from the injection in a Atlantic-like mantle of a component with a low 206Pb/204Pb ratio, and relatively high 87Sr/86Sr, 207Pb/204Pb and 208Pb/204Pb ratios. This component has been associated to a plume (Kerguelen), to a thermally delaminated subcontinental lithosphere, to lower crust or to subduction of a mixture of sediments and old oceanic crust. In order to constrain the different hypothesis, we have performed a complete rare gas study (He, Ne, Ar, Kr and Xe) in basalts both from mid oceanic ridges and some oceanic islands from Indian ocean. The helium isotopic ratios of the most DUPAL-like samples are more radiogenic than in Pacific and Atlantic MORB (4He/3He >120,000). The 21Ne/22Ne ratio is also more nucleogenic and correlates with the helium. The significance of these characteristics is that the component injected in the Indian mantle is a material with high (U+Th)/3He and (U+Th)/22Ne and may be low 40Ar/36Ar. This kind of material is consistent with subcontinental mantle or lower crust, isolated from the mantle convection for more than 1.5Ga, previously enriched by fluids coming from dehydration of subducted slabs

Postmeiotic cytokinesis and pollen aperture number determination in eudicots: effect of the cleavage wall number

International audienceIn eudicot postmeiotic tetrads, apertures are usually joined in pairs in highly conserved areas. These appear to be located at the last points of contact persisting at the end of cytokinesis between the cytoplasm of the future microspores. In order to investigate the relationship between cytokinesis and aperture formation, aperture distribution within postmeiotic tetrads and the progression of meiosis were studied in Nicotiana tabacum cv. Ambalema. This variety (inbred line) produces about 85% tricolporate pollen and 15% tetracolporate pollen grains. In addition, about 7% of tetrads are composed of four equal-sized microspores and a supernumerary pseudomicrospore of small size and an equal proportion of tetrads exhibit unpaired apertures (these apertures are not joined in pairs within tetrads). Observation of cytokinesis indicates that both unpaired apertures and pseudomicrospores could result from the persistence of late communications between microsporocytes. Observations of tetrads indicate that an increase in the number of elements that are separated during cytokinesis is correlated with an increase in microspore aperture number. All data converge to support the hypothesis that aperture site determination is partly controlled by the number of walls formed to separate the different elements of the tetrad