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

Molecular imaging in schizophrenia spectrum disorders

In this chapter, we aim to shed light on the schizophrenia spectrum disorders using molecular imaging. Schizophrenia spectrum disorders consist primarily of the disorders with full-blown psychosis in their course and are grouped in the DSM-V category of schizophrenia and other psychotic disorders. The treatment of psychosis has been very successful in the era of psychopharmacology, starting with the discovery of the "neuroleptic" drug chlorpromazine (Largactil). The notion that the so-called typical antipsychotics bind to dopamine D2 and D3 receptors is one of the cornerstones of the dopamine hypothesis of schizophrenia (Davis et al., Am J Psychiatry 148:1474-1486, 1991). For more than a decade, this hypothesis has been the most influential hypothesis in schizophrenia research. It postulates that schizophrenia is a manifestation of a "hyperdopaminergic" state in some regions of the brain. The binding of antipsychotics to D2/D3 receptors can be directly visualized and quantified with dopamine receptor PET and SPECT ligands, such as [11C]-raclopride or [123I]-IBZM, respectively (Laruelle, Q J Nucl Med 42:211-221, 1998). Typical antipsychotics bind to D2/D3 receptors and displace these radiotracers from the postsynaptic receptors in the dopamine projection areas, such as the striatum, providing a unique way to quantify occupancy of these compounds to the D2/D3 receptors. In one of the first human studies with [11C]-raclopride, described that an occupancy of 70-80% of the D2/D3 receptors was sufficient for its antipsychotic effects while parkinsonistic effects were associated with much higher occupancies. The anti-dopaminergic effects in the striatum explain the major side effect of typical antipsychotics, i.e., parkinsonism. Very efficacious second-line or "atypical" antipsychotics appear to be less dependent on D2 blockade for clinical effect. The major example of this line of drugs is clozapine. Clozapine acts partly by its affinity for the postsynaptic 5HT2A receptor but has "pleiotropic" effects by affecting many other neurotransmitter receptors, hormone receptors, and inflammatory mediators. However, it was found that the newer "atypical" antipsychotics marketed after clozapine still bind for a large proportion to dopamine D2/D3 receptors, which contributes significantly to their antipsychotic efficacy. Despite the enormous progress in the development of antipsychotics, and growth of choice for the clinician to treat schizophrenia, the effect remains limited to a suppressive effect on the positive psychotic symptoms, like delusions and hallucinations. Antipsychotics do not cure the disease and have major metabolic side effects, like weight gain, increasing the risk for diabetes enormously. Therefore, more knowledge on the working mechanism and the discovery of alternative molecular pathways of treatment are needed. It is the aim of this chapter to translate molecular imaging in experimental models of schizophrenia and patients to better understand the etiopathogenesis of the clinical syndrome of schizophrenia. The ultimate aim is to design better prevention, care, and cure for schizophrenia by pinpointing to the molecular focus of the disease process.</p

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

Resilience of rice (Oryza spp.) pollen germination and tube growth to temperature stress

Resilience of rice cropping systems to potential global climate change will partly depend on the temperature tolerance of pollen germination (PG) and tube growth (PTG). Pollen germination of high temperature-susceptible Oryza glaberrima Steud. (cv. CG14) and Oryza sativa L. ssp. indica (cv. IR64) and high temperature-tolerant O. sativa ssp. aus (cv. N22), was assessed on a 5.6–45.4 °C temperature gradient system. Mean maximum PG was 85% at 27 °C with 1488 µm PTG at 25 °C. The hypothesis that in each pollen grain, the minimum temperature requirements (Tn) and maximum temperature limits (Tx) for germination operate independently was accepted by comparing multiplicative and subtractive probability models. The maximum temperature limit for PG in 50% of grains (Tx(50)) was the lowest (29.8 °C) in IR64 compared with CG14 (34.3 °C) and N22 (35.6 °C). Standard deviation (sx) of Tx was also low in IR64 (2.3 °C) suggesting that the mechanism of IR64’s susceptibility to high temperatures may relate to PG. Optimum germination temperatures and thermal times for 1 mm PTG were not linked to tolerating high temperatures at anthesis. However, the parameters Tx(50) and sx in the germination model define new pragmatic criteria for successful and resilient PG, preferable to the more traditional cardinal (maximum and minimum) temperatures