Populations of doubled haploids for genetic mapping in hexaploid winter triticale.

To create a framework for genetic dissection of hexaploid triticale, six populations of doubled haploid (DH) lines were developed from pairwise hybrids of high-yielding winter triticale cultivars. The six populations comprise between 97 and 231 genotyped DH lines each, totaling 957 DH lines. A consensus genetic map spans 4593.9 cM is composed of 1576 unique DArT markers. The maps reveal several structural rearrangements in triticale genomes. In preliminary tests of the populations and maps, markers specific to wheat segments of the engineered rye chromosome 1R (RM1B) were identified. Example QTL mapping of days to heading in cv. Krakowiak revealed loci on chromosomes 2BL and 2R responsible for extended vernalization requirement, and candidate genes were identified. The material is available to all parties interested in triticale genetics

Gametophytic development of Brassica napus pollen in vitroenables examination of cytoskeleton and nuclear movements

Isolated microspores and pollen suspension of Brassica napus “Topas” cultured in NLN-13 medium at 18°C follow gametophytic pathway and develop into pollen grains closely resembling pollen formed in planta. This culture system complemented with whole-mount immunocytochemical technology and novel confocal laser scanning optical technique enables detailed studies of male gametophyte including asymmetric division, cytoskeleton, and nuclear movements. Microtubular cytoskeleton configurationally changed in successive stages of pollen development. The most prominent role of microtubules (MTs) was observed just before and during nuclear migration at the early and mid-bi-cellular stage. At the early bi-cellular stage, parallel arrangement of cortical and endoplasmic MTs to the long axis of the generative cell (GC) as well as MTs within GC under the plasmalemma bordering vegetative cell (VC) were responsible for GC lens shape. At the beginning of the GC migration, endoplasmic microtubules (EMTs) of the VC radiated from the nuclear envelope. Most cortical and EMTs of the VC were found near the sporoderm. At the same time, pattern of MTs observed in GC was considerably different. Multiple EMTs of the GC, previously parallel aligned, reorganized, and start to surround GC, forming a basket-like structure. These results suggest that EMTs of GC provoke changes in GC shape, its detachment from the sporoderm, and play an important role in GC migration to the vegetative nucleus (VN). During the process of migration of the GC to the VC, multiple and thick bundles of MTs, radiating from the cytoplasm near GC plasma membrane, arranged perpendicular to the narrow end of the GC and organized into a “comet-tail” form. These GC “tail” MTs became shortened and the generative nucleus (GN) took a ball shape. The dynamic changes of MTs accompanied polarized distribution pattern of mitochondria and endoplasmic reticulum. In order to confirm the role of MTs in pollen development, a “whole-mount” immunodetection technique and confocal laser-scanning microscopy was essential

In vitro embryo rescue and plant regeneration following self-pollination with irradiated pollen in cassava (Manihot esculenta Crantz)

Cassava is a highly heterozygous species; hence, current methods used in classical cassava breedingcannot match the urgent need to high yielding varieties. Recently, progress was made through androgenesis and gynogenesis as pathways for raising doubled cassava haploid lines to overcome problems associated with cassava’s inherent reproductive biology, but these efforts were limited (nocandidate cassava plantlets were regenerated). For the first time, this study shows that pollen irradiation coupled with self-pollination and embryo rescue regenerated 62 candidate cassava plantlets. Plants of an elite cassava variety, Nase14, served as a mother plant and as the pollen donor for the irradiation. Irradiation dosages of 50 to 250 Gray studied across five pollination events and 300 or 500 Gray in one pollination event caused a reduction in pollen germination up to 67.0%. By 15 days after pollination (DAP) with irradiated pollen, up to 89.7% of the pollinated flowers had aborted. By embryo rescue time (42 DAP), significant differences were observed in number of fruits, seeds and embryos generated, with the non-irradiated pollen treatments having significantly higher numbers. Sixteen (16) heterozygous SSR markers in the parent and ploidy analysis showed that none of the regenerated plants was haploid or homozygous. However, the plantlets resulting from pollination with non-irradiated pollen had 56.2% homozygous loci, while progeny derived from irradiated treatments had frequencies of homozygous loci between 28.1 and 55.0%. This is the first time to use irradiated pollen in cassava as a pathway to generate candidate plantlets as an initial step in double haploid production.Key words: Cassava, doubled haploids, embryo rescue, plant regeneration, pollen germination, pollenirradiation

A comparison of low-dose risperidone to paroxetine in the treatment of panic attacks: a randomized, single-blind study

<p>Abstract</p> <p>Background</p> <p>Because a large proportion of patients with panic attacks receiving approved pharmacotherapy do not respond or respond poorly to medication, it is important to identify additional therapeutic strategies for the management of panic symptoms. This article describes a randomized, rater-blind study comparing low-dose risperidone to standard-of-care paroxetine for the treatment of panic attacks.</p> <p>Methods</p> <p>Fifty six subjects with a history of panic attacks were randomized to receive either risperidone or paroxetine. The subjects were then followed for eight weeks. Outcome measures included the Panic Disorder Severity Scale (PDSS), the Hamilton Anxiety Scale (Ham-A), the Hamilton Depression Rating Scale (Ham-D), the Sheehan Panic Anxiety Scale-Patient (SPAS-P), and the Clinical Global Impression scale (CGI).</p> <p>Results</p> <p>All subjects demonstrated a reduction in both the frequency and severity of panic attacks regardless of treatment received. Statistically significant improvements in rating scale scores for both groups were identified for the PDSS, the Ham-A, the Ham-D, and the CGI. There was no difference between treatment groups in the improvement in scores on the measures PDSS, Ham-A, Ham-D, and CGI. Post hoc tests suggest that subjects receiving risperidone may have a quicker clinical response than subjects receiving paroxetine.</p> <p>Conclusion</p> <p>We can identify no difference in the efficacy of paroxetine and low-dose risperidone in the treatment of panic attacks. Low-dose risperidone appears to be tolerated equally well as paroxetine. Low-dose risperidone may be an effective treatment for anxiety disorders in which panic attacks are a significant component.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov Identifier: NCT100457106</p

Wpływ substancji chemicznych aktywujących i hamujących program selektywnej śmierci komórek na przebieg androgenezy w kulturach izolowanych mikrospor tytoniu (Nicotiana tabacum L.) - badania wstępne

Developmental pathway of isolated microspores in in vitro cultures of tobacco (Nicotiana tabacum L.), treated with chemical agents known as inducers or inhibitors of various forms of PCD was under the study. Microspores at unicellular stage of development were isolated and cultured according to the method described by Touraev and Heberle-Bors (1999). Chemical agents known as an inducer (tunikamycin, Tun) and inhibitor (leupeptin, Leu) of apoptosis, and inducer of autophagy (rapamycin, Rap) were applied to cultures continuing gamethopytic or inducing sporophytic developmental pathway and its effect on microspore development was observed. All chemicals were tested at several concentrations and several lengths of the treatment period, which were selected on the basis of literature data. Microspores treated with Rap continued its gametophytic development: majority of microspores divided asymmetrically and no significant influence of Rap could be detected. The effect of Tun was strongly depended on the duration of the Tun treatment. A short Tun treatment (1-5 h) increased slightly the number of symmetrically dividing microspores. A prolonged period of Tun treatment (12 h) resulted in a significant increase in the number of symmetrically dividing microspores (from 3% to 33%). Further prolongation of Tun treatment (24 h) had lethal influence: the number of symmetrically dividing microspores increased from 1 to 14% but the viability of cultures decreased from 57% to 20%. However, in any case further embryogenic development of dividing structures was observed - a subsequent culture resulted in its progressive degeneration and death. In cultures induced towards sporophytic development a clear evidence of Leu influence on the microspore development was found. The effect of Leu application was strongly correlated with the concentration and the time of treatment. In Leu treated cultures a significant decrease in the number of embryogenic microspores and stimulation of starch accumulation was noted. Also in this case an accumulative effect of DMSO could be observed. Longer than 2 day DMSO treatment had lethal influence and increased the number of degenerated microspores by about 18-32%. This effect was strengthened when higher concentrations of Leu were applied (30 versus 10 µmol·dm⁻³). The received results indicates that the application of autophagy inhibiting agent was essential for surviving the sucrose/nitrogen starvation period - the trigger of androgenesis in isolated microspore cultures of tobacco, and that inducer of apoptosis can inhibit gametophytic pathway but was not sufficient for a successful induction of sporophytic microspore development. These experiments are the introduction to further, more detailed examination.Przeprowadzone badania miały na celu zbadanie wpływu, jaki na przebieg procesu androgenezy w kulturach izolowanych mikrospor tytoniu (Nicotiana tabacum L. cv. 'Petit Havana’ SR1) wywierać mogą substancje znane jako aktywatory i inhibitory poszczególnych form programowanej śmierci komórek. Mikrospory w fazie jednojądrowej izolowano i hodowano metodą opisaną przez Touraeva i Heberle-Borsa (1999). W doświadczeniach wykorzystano: tunikamycynę (Tun), rapamycynę (Rap), oraz leupetynę (Leu), znane jako aktywatory i inhibitory procesów apoptozy i autofagii, odpowiednio w kulturach kontynuujących rozwój gametofityczny oraz w kulturach androgenicznych. Każdą z testowanych substancji stosowano w określonym zakresie stężeń oraz przedziale czasowym, które dobrane zostały na podstawie dostępnych w literaturze danych. W kulturach izolowanych mikrospor tytoniu nie stwierdzono istotnego wpływu Rap na kierunek rozwoju mikrospor - przeważająca część populacji inicjowała asymetryczne podziały komórkowe świadczące o kontynuacji rozwoju gametofitycznego. Obecność Tun stymulowała inicjację symetrycznych podziałów komórkowych, co mogłoby sugerować indukcję androgenezy. Efekt oddziaływania Tun uzależniony był od czasu traktowania: krótkotrwała obecność (1-5 h) Tun nieznacznie podniosła częstotliwość symetrycznych podziałów komórkowych, wydłużona do 12 h - wywołała istotny wzrost (z 3% do 33%) liczby symetrycznie dzielących się mikrospor, w kulturach traktowanych Tun przez 24 h oprócz stymulacji podziałów symetrycznych (z 1 do 14%) obserwowano istotny spadek żywotności kultur (prawie dwukrotny wzrost liczby zdegenerowanych komórek z ok. 40% do 80%). Jednakże w żadnym przypadku nie obserwowano dalszego rozwoju uzyskanych struktur, w trakcie dalszej hodowli stopniowo ulegały one degeneracji i obumieraniu. Obserwowano również istotny wpływ Leu w kulturach inicjujących proces androgenezy pod wpływem kombinacji stresu wysokotemperaturowego i „głodzenia”. W kulturach traktowanych 10 µmol Leu·dm⁻³ przez 2 dni obserwowano istotny spadek liczby embriogennych mikrospor oraz stymulację akumulacji skrobi sugerujące zahamowanie procesu androgenezy. Dłuższe traktowanie Leu (4-6 dni) oraz wyższe stężenie (30 µmol·dm⁻³ ) miały niekorzystny wpływ na żywotność traktowanych kultur. Uzyskane wyniki sugerują, że wpływ substancji indukującej apoptozę (Tun) może prowadzić do zahamowania rozwoju generatywnego mikrospor, nie jest jednak czynnikiem decydującym o uruchomieniu wydajnego sporofitycznego programu rozwoju. Natomiast Leu (inhibitor autofagi) uniemożliwia przebieg androgenezy nawet w warunkach optymalnych dla efektywnej inicjacji procesu. Wyniki te stanowią podstawę do dalszych bardziej szczegółowych badań