Virulence of Pyrenophora tritici-repentis: a minireview

Pyrenophora tritici-repentis is a major wheat pathogen in all wheat (Triticum spp.) growing areas worldwide. Up to date, eight P. tritici-repentis races have been described based on chlorosis, necrosis, or both symptoms caused on race differential wheat genotypes: ‘Glenlea’, 6B662, 6B365, and ‘Salamouni’. Symptom development on differential genotypes depends on the interaction of the pathogen’s necrotrophic effectors named Ptr ToxA, Ptr ToxB, and Ptr ToxC with host susceptibility genes. Ptr ToxA is encoded by the single copy gene ToxA and induces necrosis on sensitive wheat cultivars. Ptr ToxB causes chlorosis and is encoded by the multicopy gene ToxB. The Ptr ToxC is the non-proteinaceous, polar, low molecular mass molecule that also induces chlorosis, but up to date, the gene encoding this toxin is unknown. Races producing Ptr ToxA are predominant in the global Ptr population. There are several reports about new putative races of P. tritici-repentis that do not conform with the current race system, so further research is required. This study aims to collect and systematise available information about the virulence and races of P. tritici-repentis.

High-Resolution Polar Low Winds Obtained from Unsupervised SAR Wind Retrieval

High-resolution sea surface observations by spaceborne synthetic aperture radar (SAR) instruments are sorely neglected resources for meteorological applications in polar regions. Such radar observations provide information about wind speed and direction based on wind-induced roughness of the sea surface. The increasing coverage of SAR observations in polar regions calls for the development of SAR-specific applications that make use of the full information content of this valuable resource. Here we provide examples of the potential of SAR observations to provide details of the complex, mesoscale wind structure during polar low events, and examine the performance of two current wind retrieval methods. Furthermore, we suggest a new approach towards accurate wind vector retrieval of complex wind fields from SAR observations that does not require a priori wind direction input that the most common retrieval methods are dependent on. This approach has the potential to be particularly beneficial for numerical forecasting of weather systems with strong wind gradients, such as polar lows.

A global climatology of polar lows investigated for local differences and wind-shear environments

Polar lows are intense mesoscale cyclones developing in marine polar air masses. This study presents a new global climatology of polar lows based on the ERA-5 reanalysis for the years 1979–2020. Criteria for the detection of polar lows are derived based on a comparison of six polar-low archives with cyclones derived by a mesoscale tracking algorithm. The characteristics associated with polar lows are considered by the criteria: (i) intense cyclone: large relative vorticity, (ii) mesoscale: small vortex diameter, and (iii) development in the marine polar air masses: combination of low dry-static stability and low potential temperature at the tropopause. Polar lows develop in all marine areas adjacent to sea ice or cold landmasses, mainly in the winter half-year. The length and intensity of the season are regionally dependent. The highest density appears in the Nordic Seas. For all ocean sub-basins, forward-shear polar lows are the most common, whereas weak shear and those propagating towards warmer environments are second and third most frequent, depending on the area. Reverse-shear polar lows and those propagating towards colder environments are rather seldom, especially in the Southern Ocean. Generally, PLs share many characteristics across ocean basins and wind-shear categories. The most remarkable difference is that forward-shear polar lows are often occurring in stronger vertical wind shear, whereas reverse-shear polar lows feature lower static stability. Hence, the contribution to a fast baroclinic growth rate is slightly different for the shear categories.

Generalizable Compositional Features Influencing the Proteostatic Fates of Polar Low-Complexity Domains

Protein aggregation is associated with a growing list of human diseases. A substantial fraction of proteins in eukaryotic proteomes constitutes a proteostasis network—a collection of proteins that work together to maintain properly folded proteins. One of the overarching functions of the proteostasis network is the prevention or reversal of protein aggregation. How proteins aggregate in spite of the anti-aggregation activity of the proteostasis machinery is incompletely understood. Exposed hydrophobic patches can trigger degradation by the ubiquitin-proteasome system, a key branch of the proteostasis network. However, in a recent study, we found that model glycine (G)-rich or glutamine/asparagine (Q/N)-rich prion-like domains differ in their susceptibility to detection and degradation by this system. Here, we expand upon this work by examining whether the features controlling the degradation of our model prion-like domains generalize broadly to G-rich and Q/N-rich domains. Experimentally, native yeast G-rich domains in isolation are sensitive to the degradation-promoting effects of hydrophobic residues, whereas native Q/N-rich domains completely resist these effects and tend to aggregate instead. Bioinformatic analyses indicate that native G-rich domains from yeast and humans tend to avoid degradation-promoting features, suggesting that the proteostasis network may act as a form of selection at the molecular level that constrains the sequence space accessible to G-rich domains. However, the sensitivity or resistance of G-rich and Q/N-rich domains, respectively, was not always preserved in their native protein contexts, highlighting that proteins can evolve other sequence features to overcome the intrinsic sensitivity of some LCDs to degradation.

Discovery and validation of a genomic signature to identify women with early-stage invasive breast cancer who may safely omit adjuvant radiotherapy after breast-conserving surgery.

512 Background: Adjuvant radiotherapy (RT) is currently the standard of care for women with early-stage invasive breast cancer (BC) treated with breast conserving surgery (BCS). However, some women may have very low risk of recurrence and could safely be spared RT. This study aimed to identify these women using a molecularly-based approach. Methods: We performed an analysis of the SweBCG91-RT cohort, a trial randomizing women with node-negative stage I-II invasive BC +/- RT following breast conserving surgery, with sparse use of adjuvant systemic therapy. Only patients with ER+, HER2- tumors, and not treated with adjuvant systemic therapy, were included in this analysis. Transcriptome-wide profiling of tumors was performed using the Affymetrix Human Exon 1.0 ST microarray. The SweBCG91-RT cohort was divided into a training cohort of 243 patients and a validation cohort of 354 patients. Biological gene sets and individual genes related to locoregional recurrence in patients not receiving RT of the training set were identified, and a 16-gene signature was trained using elastic net regression. The signature, named Profile for the Omission of Local Adjuvant Radiation (POLAR), was locked prior to validation. Results: In the validation cohort, POLAR was prognostic for locoregional recurrence (LRR) in patients not treated with RT (multivariable Cox model adjusting for age, grade, tumor size, and luminal A vs luminal B: HR = 1.7 [1.2,2.3], p < 0.001). Patients categorized as POLAR low-risk had a 10-year locoregional recurrence rate of 7% in the absence of RT. Notably, there was no significant benefit from RT for these POLAR low-risk patients (HR = 1.1 [0.38,3.3], p = 0.83), whereas patients categorized as POLAR high-risk had a significant decreased risk of locoregional recurrence when treated with RT (recurrence rate without RT at 10-years 19%, HR = 0.43 [0.24,0.78], p = 0.0053). Conclusions: These data suggest that the novel POLAR genomic signature based on LRR biology can not only identify patients who have a low risk of LRR without adjuvant RT after BCS but who also would not benefit from RT, thus being prime candidates for RT omission.

Polar Lows - Moist Baroclinic Cyclones Developing in Four Different Vertical Wind Shear Environments

&lt;p&gt;Polar lows are intense mesoscale cyclones that develop in polar marine air masses. Motivated by the large variety of their proposed intensification mechanisms, cloud structure, and ambient sub-synoptic environment, we use self-organising maps to classify polar lows. &lt;/p&gt;&lt;p&gt;We identify five different polar-low configurations which are characterised by the vertical wind shear vector, the change of the horizontal-wind vector with height, relative to the propagation direction. Four categories feature a strong shear with different orientations of the shear vector, whereas the fifth category contains conditions with weak shear. This confirms the relevance of a previously identified categorisation into forward and reverse-shear polar lows. We expand the categorisation with right and left-shear polar lows that propagate towards colder and warmer environments, respectively.&lt;/p&gt;&lt;p&gt;For the strong-shear categories, the shear vector organises the moist-baroclinic dynamics of the systems. This is apparent in the low-pressure anomaly tilting with height against the shear vector, and the main updrafts occurring along the warm front located in the forward-left direction relative to the shear vector. These main updrafts contribute to the intensification through latent-heat release and are typically associated with comma-shaped clouds.&lt;/p&gt;&lt;p&gt;Polar low situations with a weak shear, that often feature spirali-form clouds, occur mainly at decaying stages of the development. We thus find no evidence for hurricane-like intensification of polar lows and propose instead that spirali-form clouds are associated with a warm seclusion process.&lt;/p&gt;

Methods of modeling the polar low development

&lt;p&gt;The ice cover decrease in the Arctic in the past decade has led to polar hurricanes (polar lows) occurring along the entire Northern Sea Route. Wind speeds of these hurricanes reach 35-40 m / s. Over the past 20 years, significant progress in predicting storm trajectories has been achieved, while the quality of forecasting their intensity is still poor. This is due to the fact that the intensity (maximum wind speed and minimum pressure) is determined by the interaction of the atmosphere and the ocean, and at high wind speeds it has significant uncertainty, especially for the smallest-scale processes: splashes, wave collapses and foam bubbles [1].&lt;/p&gt;&lt;p&gt;Numerical modeling of the polar low development was carried out within the framework of the WRF model [2] in order to develop methods for modeling such extreme events. The water area of the Barents Sea was considered, where a large number of polar hurricanes were observed. Among the identified polar hurricanes [3], a hurricane that took place on 02/05/2009 and was observed at coordinates 69&amp;#186; N, 40&amp;#186; E was chosen. Several approaches were considered to simulate the weather conditions in the studied area of the Barents Sea in the presence of a polar hurricane. The WRF model simulation with the CFSR reanalysis was carried out. The configuration of the model consisted in using, first, the well-proven technique of Large Eddy Simulation (LES) modeling of the planetary boundary layer (PBL). Secondly, the simulation was performed using the WRF add-in for the polar region, Polar WRF [4]. The comparison of the approaches is made. The mechanism of intensification of the atmospheric vortex is considered whether it is baroclinic shear, heat fluxes on the surface or outcome of latent heat during condensation.&lt;/p&gt;&lt;p&gt;This work was supported by a RFBR grant &amp;#8470; 18-05-60299.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;1. Troitskaya, Yu, et al. &quot;Bag-breakup fragmentation as the dominant mechanism of sea-spray production in high winds.&quot; Scientific reports7.1 (2017): 1-4.&lt;br&gt;2. A Description of the Advanced Research WRF Version 3 / W. C. Skamarock, J. B. Klemp, J. Dudhia, D. O. Gill, D. M. Barker, M. G. Duda, X.-Y. Huang, W. Wang, J. G. Powers // NCAR TECHNICAL NOTE. - 2008. - &amp;#8470;NCAR/TN&amp;#8211;475+STR. - &amp;#1057;. 113 pp.&lt;br&gt;3. Noer, G., &amp; Lien, T. (2010). Dates and Positions of Polar lows over the Nordic Seas between 2000 and 2010. Norwegian Meteorological Institute Rep.&lt;br&gt;4. Hines, Keith M., et al. &quot;Development and testing of Polar WRF. Part III: Arctic land.&quot; Journal of Climate24.1 (2011): 26-48.&lt;/p&gt;

Satellite-Derived Spatio-Temporal Distribution and Parameters of North Atlantic Polar Lows for 2015–2017

A list of North Atlantic polar lows was compiled for 2015–2017. A total of 131 polar lows were found by analyzing the Moderate Resolution Imaging Spectroradiometer (MODIS) infrared imagery and auxiliary information. The study region was additionally divided by the 20° W meridian to assess possible differences in the polar lows occurring in the western and eastern parts of the region. The highest polar low activity was found over the Barents Sea and the northern Norwegian Sea. A large number of polar lows over this region were dual or multiple. When considering such systems as a single event, more polar lows were found in 2015 over the Labrador Sea and southern Davis Strait, which is the region with the second highest number of polar lows. High interannual variability of polar low frequency was noted, which was more pronounced in the western part of the region. During the analyzed period, the largest number of polar lows occurred in January for the western part of the region and in February for the eastern part. The main polar low parameters were similar within the region, with the mean values slightly higher in the western part of the region, but all extreme high values were observed in the eastern part.