The moduli space of hypersurfaces whose singular locus has high dimension

Let $k$ be an algebraically closed field and let $b$ and $n$ be integers with $n\geq 3$ and $1\leq b \leq n-1.$ Consider the moduli space $X$ of hypersurfaces in $\mathbb{P}^n_k$ of fixed degree $l$ whose singular locus is at least $b$-dimensional. We prove that for large $l$, $X$ has a unique irreducible component of maximal dimension, consisting of the hypersurfaces singular along a linear $b$-dimensional subspace of $\mathbb{P}^n$. The proof will involve a probabilistic counting argument over finite fields.Comment: Final version, including the incorporation of all comments by the refere

The S-layer protein DR_2577 binds deinoxanthin and under desiccation conditions protects against UV-radiation in Deinococcus radiodurans

Deinococcus radiodurans has the puzzling ability to withstand over a broad range of extreme conditions including high doses of ultraviolet radiation and deep desiccation. This bacterium is surrounded by a surface layer (S-layer) built of a regular repetition of several proteins, assembled to form a paracrystalline structure. Here we report that the deletion of a main constituent of this S-layer, the gene DR_2577, causes a decrease in the UVC resistance, especially in desiccated cells. Moreover, we show that the DR_2577 protein binds the carotenoid deinoxanthin, a strong protective antioxidant specific of this bacterium. A further spectroscopical characterization of the deinoxanthin-DR_2577 complex revealed features which could suggest a protective role of DR_2577. We propose that, especially under desiccation, the S-layer shields the bacterium from incident ultraviolet light and could behave as a first lane of defense against UV radiation

Population genomics of selectively neutral genetic structure and herbicide resistance in UK populations of Alopecurus myosuroides

BACKGROUND Alopecurus myosuroides (blackgrass) is a major weed in Europe with known resistance to multiple herbicide modes of action. In the UK, there is evidence that blackgrass has undergone a range expansion. In this paper, genotyping‐by‐sequencing and population‐level herbicide resistance phenotypes are used to explore spatial patterns of selectively neutral genetic variation and resistance. We also perform a preliminary genome‐wide association study and genomic prediction analysis to evaluate the potential of these approaches for investigating non‐target site herbicide resistance. RESULTS Blackgrass was collected from 47 fields across the British Isles and up to eight plants per field population (N = 369) were genotyped by RAD‐sequencing. 20,426 polymorphic loci were identified and used for population genetic analyses. Phenotypic assays revealed significant variation in herbicide resistance between populations. Population structure was weak (FST = 0.024‐0.048), but spatial patterns were consistent with an ongoing westward and northward range expansion. We detected strong and consistent Wahlund effects (FIS = 0.30). There were no spatial patterns of herbicide resistance or evidence for confounding with population structure. Using a combination of population‐level GWAS and genomic prediction we found that the top 20, 200, and 2,000 GWAS loci had higher predictive abilities for fenoxaprop resistance compared to all markers. CONCLUSION There is likely extensive human‐mediated gene flow between field populations of the weed, blackgrass at a national scale. The lack of confounding of adaptive and neutral genetic variation can enable future, more extensive GWAS analyses to identify the genetic architecture of evolved herbicide resistance

In vitro evaluation of combination effects of doxorubicin with methylxanthine fractions isolated from Bancha and Pu-erh teas against breast cancer cells

Background: In the present study we investigated the combination effects of anthracycline antibiotic, doxorubicin, with methylxanthine fractions isolated from Bancha and Pu-erh tea leaves, against MCF-7 and MDA-MB-231 breast cancer cell lines.Methods: Neutral red uptake assay was used for assessment of cytotoxicity effects and fractional effect analysis and combination index for evaluation of the combination effects.Results: Doxorubicin was used in varying concentrations by a double dilution method, whereas the methylxanthine fractions were in fixed concentrations – 100, 200, 400 or 600 μg/ml. Results have shown that methylxanthine fraction isolated from Bancha has synergic effects with doxorubicin, while methylxanthines from Pu-erh displayed antagonistic effects.Conclusions: Тhe obtained results lead us to suspect, that even minor differences in the composition of natural products can lead to significant differences in the biological activity of the product

IMMUNE RESPONSE IN MALIGNANT GLIOMA

Objective: Malignant gliomas are primary brain tumors with excessive mortality and high resistance to chemotherapy and radiotherapy. The survival time for glioblastoma multi­forme is about 6-12 months. As key pathogenetic mechanisms are recognized the massive necrosis, angiogenesis and hypoxia within the tumor, as well as the resistance to apoptosis. It is also suspected that altered immune response might contribute to the fatal clinical outcome.The aim of the present study was to determine the immune status of patients with malignant gliomas.Material and methods: Peripheral blood lymphocytes were collected preoperatively from 9 patients (aged 57-76) diagnosed as anaplastic astrocytoma grade III (n=4) and glioblastoma multiforme (n=5). The following lymphocyte populations were analyzed by flow cytometry: CD19+, CD3+, CD3+CD4+, CD3+CD8+, CD3-CD56+, CD3+CD56+, CD3+CD25+, CD8-CD11b+, CD8+CD11b+, CD8+CD11b-. The results obtained were compared to reference values for each cell population.Results: No significant alterations were detected in CD19+, CD3+, CD3+CD4+, CD3+CD8+ cells, but the CD4/CD8 ratio was below the reference range in some cases. No obvious decrease in (CD3-CD56+) NK cells and (CD3-CD56+) NKT cells was observed in most patients. A reproducible phenomenon of increased CD8+CD11b+ and decreased CD8+CD11b- cells was noticed. These preliminary results suggest that the immune response in patients with malignant glioma is seriously disregulated. The rapid clinical deterioration, relapses and high mortality could be at least partially explained with the suppressed activity of NK-cells which are the major cytotoxic antitumoral cells. The increase in the population of activated suppressor-effector cells also contributes to the unfavourable outcome in malignant brain tumors.Conclusion: This pilot study reveals the presence of altered immune response in malignant gliomas and opens possibilities for prospective investigations concerning immune status and clinical outcome

In vitro antiviral activities of fruit extract from Lycium barbarum and methylxanthines extracted from Pu-erh and Bancha tea leaves

Introduction: Based on traditional medicine, many countries use various plant products (fruits, leaves and other plant parts) as food supplements or in the form of tea. The use of these plant sources has been established through the years of use and the proven benefits of their ingredients to improve human health. Aim: In the present study, we have focused on the effect of Lycium barbarum fruit extract and methylxanthines isolated from Pu-erh (MXP) and Bancha (MXB) tea leaves on Herpes simplex virus type 1 (HSV-1), poliovirus 1 (PV1) and coxsackievirus B1 (CVB1) virus in vitro. Materials and methods: We used in vitro antiviral and virus attachment assays to determine the effects of the three extracts we studied. Results: None of the extracts showed significant inhibition of replication of the three treated viruses but a remarkable inhibitory effect on extracellular virions of HSV-1 was exhibited 30 minutes after exposure, especially by the Lycium barbarum extract. The inhibitory effect of the three extracts on the level of adsorption of the HSV-1 to sensitive cells (MDBK) was also significant, with the most pronounced effect of the MXP. The protective effect of the extracts against herpes infection on healthy cells was also determined, the MXP showing the most notable effect. Conclusions: The three studied extracts can be used effectively in the treatment of herpes infections, as well as in infections with other enveloped viruses

Functional QTL mapping and genomic prediction of canopy height in wheat measured using a robotic field phenotyping platform

Genetic studies increasingly rely on high-throughput phenotyping, but the resulting longitudinal data pose analytical challenges. We used canopy height data from an automated field phenotyping platform to compare several approaches to scanning for quantitative trait loci (QTLs) and performing genomic prediction in a wheat recombinant inbred line mapping population based on up to 26 sampled time points (TPs). We detected four persistent QTLs (i.e. expressed for most of the growing season), with both empirical and simulation analyses demonstrating superior statistical power of detecting such QTLs through functional mapping approaches compared with conventional individual TP analyses. In contrast, even very simple individual TP approaches (e.g. interval mapping) had superior detection power for transient QTLs (i.e. expressed during very short periods). Using spline-smoothed phenotypic data resulted in improved genomic predictive abilities (5–8% higher than individual TP prediction), while the effect of including significant QTLs in prediction models was relatively minor (<1–4% improvement). Finally, although QTL detection power and predictive ability generally increased with the number of TPs analysed, gains beyond five or 10 TPs chosen based on phenological information had little practical significance. These results will inform the development of an integrated, semi-automated analytical pipeline, which will be more broadly applicable to similar data sets in wheat and other crops