Molecular cytogenetic characterization of Roegneria ciliaris chromosome additions in common wheat

The development of alien addition lines is important both for transferring useful genes from related species into common wheat and for studying the relationship between alien chromosomes and those of wheat. Roegneria ciliaris (2n=4x=28, S^cS^cY^cY^c) is reported to be a potential source of resistance to wheat scab, which may be useful in wheat improvement. The amphiploid common wheat-R. ciliaris and BC₁F₇ or BC₂F₆ derivatives were screened by C-banding, genomic in situ hybridization (GISH), fluorescent in situ hybridization (FISH) and restriction fragment length polymorphism (RFLP) for the presence of R. ciliaris chromatin introgressed into wheat. Six lines were identified as disomic chromosome additions (DA), one as a ditelosomic addition (Dt), two as double disomic additions (dDA) and one as a monosomic chromosome addition (MA). RFLP analysis using wheat homoeologous group-specific clones indicated that the R. ciliaris chromosomes involved in these lines belong to groups 1, 2, 3, 5 and 7. The genomic affinities of the added R. ciliaris chromosomes were determined by FISH analysis using the repetitive sequence pCbTaq4.14 as a probe. These data suggest that the R. ciliaris chromosomes in five lines belong to the S^c genome. Based on the molecular cytogenetic data, the lines are designated as DA2S^c#1, Dt2S^c#1L, DA3S^c#1, dDA1S^c#2+5Y^c#1, DA5Y^c#1, DA7S^c#1, DA7Y^c#1 and MA?Y^c#1. Based on the present and previous work, 8 of the 14 chromosomes of R. ciliaris have been transferred into wheat.     

Development and characterization of a compensating wheat-Thinopyrum intermedium Robertsonian translocation with Sr44 resistance to stem rust (Ug99)

The emergence of the highly virulent Ug99 race complex of the stem rust fungus (Puccinia graminis Pers. f. sp. tritici Eriks. and Henn.) threatens wheat (Triticum aestivum L.) production worldwide. One of the effective genes against the Ug99 race complex is Sr44, which was derived from Thinopyrum intermedium (Host) Barkworth and D.R. Dewey and mapped to the short arm of 7J (designated 7J#1S) present in the noncompensating T7DS-7J#1L?7J#1S translocation. Noncompensating wheat-alien translocations are known to cause genomic duplications and deficiencies leading to poor agronomic performance, precluding their direct use in wheat improvement. The present study was initiated to produce compensating wheat-Th. intermedium Robertsonian translocations with Sr44 resistance. One compensating RobT was identified consisting of the wheat 7DL arm translocated to the Th. intermedium 7J#1S arm resulting in T7DL?7J#1S. The T7DL?7J#1S stock was designated as TA5657. The 7DL?7J#1S stock carries Sr44 and has resistance to the Ug99 race complex. This compensating RobT with Sr44 resistance may be useful in wheat improvement. In addition, we identified an unnamed stem rust resistance gene located on the 7J#1L arm that confers resistance not only to Ug99, but also to race TRTTF, which is virulent to Sr44. However, the action of the second gene can be modified by the presence of suppressors in the recipient wheat cultivars.     

Modelling expected trout ranges under current and future water temperature regimes in the Eastern Cape,South Africa

Different values have resulted in conflicts between anglers and conservation lobbies in the management of trout in South Africa. Key to the conflict is the demarcation of boundaries to areas in which brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss currently occur, or are likely to establish following stocking for angling. To provide a longer-term perspective on these areas, we developed models to link salmonid biological thermal thresholds to elevation. These, when applied spatially using a digital elevation model with a probability of occurrence model, provided the basis for estimating potentially available thermal habitat for these two cold water species. Here, we acknowledge that other variables (stocking history; river connectivity) also play a role in understanding trout distributions. Using a simple scenario of an increase in mean daily water temperatures of 2 °C, we demonstrated that both brown and rainbow trout are likely to exhibit considerable range reductions in the future. Because it is possible that these range restrictions will result in an increasing desire to introduce trout into areas above their current distribution limits for the maintenance of angling opportunities, conservation managers should prioritise these areas, with management interventions seeking to understand what will help to limit introductions.     

Selecting representative model micro-organisms

Background  

Micro-biological research relies on the use of model organisms that act as representatives of their species or subspecies, these are frequently well-characterized laboratory strains. However, it has often become apparent that the model strain initially chosen does not represent important features of the species. For micro-organisms, the diversity of their genomes is such that even the best possible choice of initial strain for sequencing may not assure that the genome obtained adequately represents the species. To acquire information about a species' genome as efficiently as possible, we require a method to choose strains for analysis on the basis of how well they represent the species.     

Bronchoabsorption; a novel bronchoscopic technique to improve biomarker sampling of the airway

Background

Current techniques used to obtain lung samples have significant limitations and do not provide reproducible biomarkers of inflammation. We have developed a novel technique that allows multiple sampling methods from the same area (or multiple areas) of the lung under direct bronchoscopic vision. It allows collection of mucosal lining fluid and bronchial brushing from the same site; biopsy samples may also be taken. The novel technique takes the same time as standard procedures and can be conducted safely.

Methods

Eight healthy smokers aged 40–65 years were included in this study. An absorptive filter paper was applied to the bronchial mucosa under direct vision using standard bronchoscopic techniques. Further samples were obtained from the same site using bronchial brushings. Bronchoalveolar lavage (BAL) was obtained using standard techniques. Chemokine (C-C Motif) Ligand 20 (CCL20), CCL4, CCL5, Chemokine (C-X-C Motif) Ligand 1 (CXCL1), CXCL8, CXCL9, CXCL10, CXCL11, Interleukin 1 beta (IL-1β), IL-6, Vascular endothelial growth factor (VEGF), Matrix metalloproteinase 8 (MMP-8) and MMP-9 were measured in exudate and BAL. mRNA was collected from the bronchial brushings for gene expression analysis.

Results

A greater than 10 fold concentration of all the biomarkers was detected in lung exudate in comparison to BAL. High yield of good quality RNA with RNA integrity numbers (RIN) between 7.6 and 9.3 were extracted from the bronchial brushings. The subset of genes measured were reproducible across the samples and corresponded to the inflammatory markers measured in exudate and BAL.

Conclusions

The bronchoabsorption technique as described offers the ability to sample lung fluid direct from the site of interest without the dilution effects caused by BAL. Using this method we were able to successfully measure the concentrations of biomarkers present in the lungs as well as collect high yield mRNA samples for gene expression analysis from the same site. This technique demonstrates superior sensitivity to standard BAL for the measurement of biomarkers of inflammation. It could replace BAL as the method of choice for these measurements. This method provides a systems biology approach to studying the inflammatory markers of respiratory disease progression.

Trial registration

NHS Health Research Authority (13/LO/0256).     

Terrigenous sediment-dominated reef platform infilling: an unexpected precursor to reef island formation and a test of the reef platform size–island age model in the Pacific

Low-lying coral reef islands are considered highly vulnerable to climate change, necessitating an improved understanding of when and why they form, and how the timing of formation varies within and among regions. Several testable models have been proposed that explain inter-regional variability as a function of sea-level history and, more recently, a reef platform size model has been proposed from the Maldives (central Indian Ocean) to explain intra-regional (intra-atoll) variability. Here we present chronostratigraphic data from Pipon Island, northern Great Barrier Reef (GBR), enabling us to test the applicability of existing regional island evolution models, and the platform size control hypothesis in a Pacific context. We show that reef platform infilling occurred rapidly (~4–5 mm yr⁻¹) under a “bucket-fill” type scenario. Unusually, this infilling was dominated by terrigenous sedimentation, with platform filling and subsequent reef flat formation complete by ~5000 calibrated years BP (cal BP). Reef flat exposure as sea levels slowly fell post highstand facilitated a shift towards intertidal and subaerial-dominated sedimentation. Our data suggest, however, a lag of ~1500 yr before island initiation (at ~3200 cal BP), i.e. later than that reported from smaller and more evolutionarily mature reef platforms in the region. Our data thus support: (1) the hypothesis that platform size acts to influence the timing of platform filling and subsequent island development at intra-regional scales; and (2) the hypothesis that the low wooded islands of the northern GBR conform to a model of island formation above an elevated reef flat under falling sea levels.

     

Production of Autopolyploid Lowland Switchgrass Lines Through In Vitro Chromosome Doubling

Switchgrass is considered one of the most promising energy crops. However, breeding of elite switchgrass cultivars is required to meet the challenges of large scale and sustainable biomass production. As a native perennial adapted to North America, switchgrass has lowland and upland ecotypes, where most lowland ecotypes are tetraploid (2n?=?4x?=?36), and most upland ecotypes are predominantly octoploid (2n?=?8x?=?72). Hybridization between lowland and upland switchgrass plants could identify new cultivars with heterosis. However, crossing between tetraploid and octoploid switchgrass is rare in nature. Therefore, in order to break down the cross incompatibility barrier between tetraploid lowland and octoploid upland switchgrass lines, we developed autoployploid switchgrass lines from an anueploid lowland cv. Alamo. In this study, colchicine was used in liquid and solid mediums to chemically induce chromosome doubling in embryogenic calli derived from cv. Alamo. Thirteen autopolyploid switchgrass lines were regenerated from seedlings and identified using flow cytometry. The autoplyploid switchgrass plants exhibited increased stomata aperture and stem size in comparison with the cv. Alamo. The most autooplyploid plants were regenerated from switchgrass calli that were treated with 0.04 % colchicine in liquid medium for 13 days. One autopolyploid switchgrass line, VT8-1, was successfully crossed to the octoploid upland cv. Blackwell. The autoployploid and the derived inter-ecotype hybrids were confirmed by in situ hybridization and molecular marker analysis. Therefore, the results of this study show that an autopolyploid, generated by chemically induced chromosome doubling of lowland cv. Alamo, is cross compatible with upland octoploid switchgrass cultivars. The outcome of this study may have significant applications in switchgrass hybrid breeding.     

Combinatorial Screening of Polymer:Fullerene Blends for Organic Solar Cells by Inkjet Printing

Polymer:fullerene blends were screened in a combinatorial approach using inkjet printing thin film libraries for photovoltaic devices. The application of inkjet printing enabled a fast and simple experimental workflow from film preparation to the study of structure‐property‐relationships with a very high material efficiency. Inkjet printing requires less material for the preparation of thin film libraries in comparison to other dispensing techniques, like spin‐coating. Two polymers (PCPDTBT, PSBTBT) and two fullerene derivatives (mono‐PCBM, bis‐PCBM) were investigated in various blend ratios, concentrations, solvent ratios, and film thicknesses. Morphological and optical properties of the inkjet printed films were investigated and compared with spin‐coated films. This study shows the principle of an experimental setup from solution preparation to film characterization for the combinatorial investigation of large polymer:fullerene libraries.