Mitochondrial DNA variability detected in a single wheat regenerant involves a rare recombination event across a short repeat

The mitochondrial genome of the selfed progeny of a plant regenerated from long-term somatic tissue culture displays specific structural rearrangements characterized by the appearance of novel restriction fragments. A mitochondrial DNA library was constructed from this selfed progeny in the SalI site of cosmid pHC79 and the novel fragments were subsequently studied. They were shown to arise from reciprocal recombination events involving DNA sequences present in the parental plant. The regions of recombination were sequenced and the nucleotide sequences were aligned with those of the presumptive parental fragments. We characterized an imperfect short repeated DNA sequence, 242 bp long, within which a 7-bb DNA repeat could act as a region of recombination. The use of PCR technology allowed us to show that these fragments were present in both parental plants and tissue cultures as low-abundance sequence arrangements.     

Comparison of the in vitro toxicity of ancient Triticum monococcum varieties ID331 and Monlis

Abstract

Triticum monococcum L. is one of the oldest ancestors of wheat. There is some evidence that einkorn encloses forms of gliadin-deriving peptides which may potentially exert a reduced toxicity to consumers with gluten-related disorders. Accordingly, ID331 and Monlis lines were comparatively investigated in this study. The biological effects of gastro-resistant peptides deriving from an in vitro simulated digestion were evaluated on 21 d differentiated Caco-2 cells. Triticum aestivum digested gliadin was included as the positive control. ID331 neither enhanced cell permeability nor induced zonulin release in Caco-2 monolayers. Monlis exerted a detectable toxicity as confirmed by the reorganisation of enterocyte cytoskeleton, in addition to changes both in monolayers permeability and apical release of zonulin. Differences in patterns of gastro-resistant prolamins may account for the differences. Outcomes support the use of ID331 as a prospective candidate for the development of innovative approaches to reduce wheat flour toxicity.     

Lack of intestinal mucosal toxicity of Triticum monococcum in celiac disease patients

Objective. The treatment of celiac disease is based on lifelong withdrawal of foods containing gluten. Unfortunately, compliance with a gluten-free diet has proved poor in many patients (mainly due to its low palatability), emphasizing the need for cereal varieties that are not toxic for celiac patients. In evolutionary terms, Triticum monococcum is the oldest and most primitive cultivated wheat. The aim of this study was to evaluate the toxicity of T. monococcum on small intestinal mucosa, using an in vitro organ culture system.

Material and methods. Distal duodenum biopsies of 12 treated celiac patients and 17 control subjects were cultured for 24?h with T. aestivum (bread) gliadin (1?mg/ml) or with T. monococcum gliadin (1?mg/ml). Biopsies cultured with medium alone served as controls. Each biopsy was used for conventional histological examination and for immunohistochemical detection of CD3?+?intraepithelial lymphocytes (IELs) and HLA-DR. Secreted cytokine protein interferon-γ (IFN–γ) was measured in the culture supernatant using an enzyme-linked immunoadsorbent assay.

Results. Significant morphological changes, HLA-DR overexpression in the crypt epithelium and an increased number of CD3?+?IELs, found after bread gliadin exposure, were not observed in celiac biopsies cultured with T. monococcum gliadin. In contrast, with bread gliadin, there was no significant IFN-γ response after culture with monococcum gliadin. Similarly, biopsies from normal controls did not respond to bread or monococcum gliadin stimulation.

Conclusions. These data show a lack of toxicity of T. monococcum gliadin in an in vitro organ culture system, suggesting new dietary opportunities for celiac patients.     

Microwave pretreatment can enhance tolerance of wheat seedlings to CdCl2 stress

In order to determine the role of microwave in cadmium stress tolerance of wheat (Triticum aestivum L.), seeds were exposed to microwave radiation for 0, 5, 10 and 15 s (wavelength 125 mm, power density 126 mW cm⁻², 2450 MHz), and when the seedlings were 7 d old (with one fully expanded leaves), they were treated with 150 μM CdCl₂ solution for 10 d. Changes in a number of physiological and biochemical characteristics were measured and used as indicators of the protective capacity of microwave radiation in this experiment. Our results showed that 150 μM CdCl₂ treatment reduced plant height, root length, dry weight, AsA and GSH concentration and the activities of SOD, POD, CAT and APX, enhanced the concentration of MDA, H₂O₂ and the production rate of O₂⁻ when compared with the control. However, seeds with microwave pretreatment 5 or 10 s conferred tolerance to cadmium stress in wheat seedlings by decreasing the concentration of MDA and H₂O₂, the production rate of O₂⁻ and increasing the activities of SOD, POD, CAT, APX and AsA and GSH concentration. Therefore, antioxidative enzymes and antioxidative compounds may participate in tolerance of wheat seedlings to cadmium stress. The results also showed that the microwave radiation had a positive physiological effect on the growth and development of cadmium stressed seedlings. This is the first investigation reporting the use of microwave pretreatment to enhance cadmium stress tolerance of wheat.     

小麦过敏原Tri a Bd 27k蛋白抗原表位预测及三维结构模拟

目的 通过生物信息学方法了解小麦过敏原Tri a Bd 27k的结构特征,为小麦变态反应性疾病的诊断和预防提供依据.方法 在Uniprot数据库中获得Tri a Bd 27k蛋白序列,通过DNAStar预测B细胞抗原表位,NetMHCⅡ和Syfpeithi预测T细胞抗原表位;使用Swiss-Model软件预测其三维结构并用Ramachandran进行稳定性评估.在Uniport 数据库搜索Tria Bd 27k的同源蛋白,应用Clustalx 1.83及Mega 3.1构建同源进化树.结果 小麦过敏原Tri a Bd 27k的B/T细胞共同抗原表位优势区域为34-42、102-117,Ramachandran软件预测结果显示小麦Tri a Bd 27k蛋白的空间构象稳定.结论 通过对小麦过敏原Tria Bd 27k进行生物信息学分析获得了该过敏原优势区域及三维结构模型,为进一步了解和掌握小麦过敏原Tri a Bd 27k的结构功能打下理论基础.