Selection of valine-resistance in callus calture of Arabidopsis thaliana (L.) Heynh. derived from leaf explants

The selection of valine-resistant mutants was carried out in leaf explant cultures of three Arabidopsis thaliana (L.) Heynh. ecotypes: C-24, RLD and Columbia. The valine concentration used for in vitro selection, lethal for seed-growing plants, has not affected callus formation and growth. However, strong inhibition of shoot regeneration ability of calli growing under selection pressure was noticed. In total, 1043 explants were cultured on valine medium and 18 shoots were regenerated with an average frequency of 1.7 shoots per 100 calli. Most R1 shoots were sterile and seeds were collected from 3 plants. The transmission of valine-resistance to the sexual progeny of these plants was scored and the increased level of valine-resistance was found in progeny of one line - 61C. This line originated from the culture of Columbia leaf explant and displayed tetraploid chromosome number

Effect of water chemistry on the planktonic communities and relationships among food web components across a freshwater ecotone

Most ecological research on the food web has been focused more on the pelagic zone than on the transitional zone - ecotones between lentic and lotic habitats. The specific goals of this study were to determine whether the contact zone of waters differs in hydrochemical and biological terms from the waters of the canal and the open water zone, and to evaluate the influence of particular macro-habitats on the interactions between components of the planktonic food web. The distribution of samples in ordination space led us to conclude that the studied habitats are distributed along the rising gradient of total organic carbon and nutrients. Assemblages of all investigated groups showed a strong compositional gradient correlated with conductivity and total phosphorus, while a second strong gradient in species composition was explained by nitrate nitrogen and/or phosphate concentrations. The analysis of trophic relationships in the system bacteriaciliates- crustaceans reveals a clear differentiation and strength of mutual relations between the analyzed zones. The highest number of significant correlations was determined in the contact zone. It can also be a place of very efficient matter and energy flow in freshwater ecosystems

Increased incidence of type 1 diabetes in children and no change in the age of diagnosis and BMI-SDS at the onset : is the accelerator hypothesis not working?

Objective: One of the hypothesized reasons for the observed increase in type 1 diabetes incidence in children is weight gain, causing accelerated disease development in predisposed individuals. This so-called accelerator hypothesis is, however, controversial. The aim was to analyze whether, in the ethnically homogeneous population of Lesser Poland, an increase in the number of cases of diabetes among children was associated with younger age and higher body mass index-standard deviation score (BMI-SDS) at the time of diagnosis. Methods: Retrospective data analysis from medical records of all patients <14 years (n=559; 50.6% male), with newly diagnosed type 1 diabetes, in Lesser Poland between 1st January 2006 and 31st December 2017 (11 years). Results: The incidence ratio ranged significantly (p<0.001) from the lowest in 2006 (11.2/100,000/year) to the highest in 2012 (21.9/100,000/year). The mean age of diagnosis was 8.2±3.5 years. There was no trend in decreasing diagnosis age (p=0.43). The mean BMI-SDS was -0.4±1.2. Almost all children (91.6%) presented with BMI-SDS within the normal range at the time of diagnosis, with only 2.7% of cases being obese and 5.7% underweight at the moment of diagnosis. There was no clear trend at all in BMI-SDS over the study period. Conclusion: These results do not corroborate an increase of type 1 incidence in paediatric population being associated with younger age of diagnosis and higher BMI-SDS. This implies that the accelerator hypothesis does not hold true in the study population

ATR, a DNA damage signaling kinase, is involved in aluminum response in barley

Ataxia Telangiectasia and Rad-3-related protein (ATR) is a DNA damage signaling kinase required for the monitoring of DNA integrity. Together with ATM and SOG1, it is a key player in the transcriptional regulation of DNA damage response (DDR) genes in plants. In this study, we describe the role of ATR in the DDR pathway in barley and the function of the HvATR gene in response to DNA damages induced by aluminum toxicity. Aluminum is the third most abundant element in the Earth’s crust. It becomes highly phytotoxic in acidic soils, which comprise more than 50% of arable lands worldwide. At low pH, Al is known to be a genotoxic agent causing DNA damage and cell cycle arrest. We present barley mutants, hvatr.g and hvatr.i, developed by TILLING strategy. The hvatr.g mutant carries a G6054A missense mutation in the ATR gene, leading to the substitution of a highly conserved amino acid in the protein (G1015S). The hvatr.g mutant showed the impaired DDR pathway. It accumulated DNA damages in the nuclei of root meristem cells when grown in control conditions. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) analysis revealed that 60% of mutant nuclei possessed DNA nicks and breaks, whereas in the wild type only 2% of the nuclei were TUNELpositive. The high frequency of DNA damages did not lead to the inhibition of the cell cycle progression, but the mutant showed an increased number of cells in the G2/M phase. In response to treatments with different Al doses, hvatr.g showed a high level of tolerance. The retention of root growth, which is the most evident symptom of Al toxicity, was not observed in the mutant, as it was in its parent variety. Furthermore, Al treatment increased the level of DNA damages, but did not affect the mitotic activity and the cell cycle profile in the hvatr.g mutant. A similar phenotype was observed for the hvatr.i mutant, carrying another missense mutation leading to G903E substitution in the HvATR protein. Our results demonstrate that the impaired mechanism of DNA damage response may lead to aluminum tolerance. They shed a new light on the role of the ATR-dependent DDR pathway in an agronomically important species

Stratification, Scarification and Application of Phytohormones Promote Dormancy Breaking and Germination of Pelleted Scots Pine (Pinus sylvestris L.) Seeds

Funding: This work was from a Subvention of the Ministry of Science and Higher Education in Poland SUB/2019-0419 000 000-D404.Peer reviewedPublisher PD

Creation of a TILLING population in barley after chemical mutagenesis with sodium azide and MNU

Since the development of the Targeting Induced Local Lesions in Genome (TILLING) strategy, it has been applied in both plants and animals in many studies. The creation of an appropriate population is the first and most crucial step of TILLING. The goal is to obtain a highly mutagenized population that allows many mutations in any gene of interest to be found. Therefore, an effective method of mutation induction should be developed. A high mutation density is associated with saving time, costs, and the labor required for the development of a TILLING platform. The proper handling of the mutated generations, the establishment of a seed bank, and the development of a DNA library are essential for creating a TILLING population. The database in which all of the data from the molecular and phenotypic analyses are collected is a very useful tool for maintaining such population. Once developed, a TILLING population can serve as a renewable resource of mutations for research that uses both forward and reverse genetic approaches. In this chapter, we describe the methods for the development and maintenance of a TILLING population in barley

Limfangioleiomiomatoza (LAM) : trudności diagnostyczne

Background: LAM is a rare idiopathic disorder found almost exclusively in premenopausal women. It is characterized by a proliferation of abnormal smooth muscle cell in the pulmonary interstitium, in the lymphatic system of the thorax, retroperitoneum and by the formation of pulmonary parenchymal cysts. The most common clinical manifestations of LAM are pulmonary symptoms including progressive dyspnoea, pneumothorax and chylous effusion. Case report: The authors describe a case of a 43-year-old woman with lymphangiomyomatosis (LAM) with initial manifestation of pneumothorax and retroperitoneal cystic mass. Conclusions: HRCT is the best method for cyst detection and is essential for diagnosis. A radiologist is often the first physician to suggest the diagnosis of LAM. However, misdiagnosis is common and may result in inappropriate therapeutic procedures that can further complicate the treatment. There are characteristic abdominal findings in patients with LAM, that in conjunction with the HRCT findings of pulmonary cysts, prove to be useful in establishing this diagnosis

Morphological, genetic and molecular characteristics of barley root hair mutants

Root hairs are tubular outgrowths of specialized epidermal cells called trichoblasts. They affect anchoring plants in soil, the uptake of water and nutrients and are the sites of the interaction between plants and microorganisms. Nineteen root hair mutants of barley representing different stages of root hair development were subjected to detailed morphological and genetic analyses. Each mutant was monogenic and recessive. An allelism test revealed that nine loci were responsible for the mutated root hair phenotypes in the collection and 1–4 mutated allelic forms were identified at each locus. Genetic relationships between the genes responsible for different stages of root hair formation were established. The linkage groups of four loci rhl1, rhp1, rhi1 and rhs1, which had previously been mapped on chromosomes 7H, 1H, 6H and 5H, respectively, were enriched with new markers that flank the genes at a distance of 0.16 cM to 4.6 cM. The chromosomal position of three new genes – two that are responsible for the development of short root hairs (rhs2 and rhs3) and the gene that controls an irregular root hair pattern (rhi2) – were mapped on chromosomes 6H, 2H and 1H, respectively. A comparative analysis of the agrobotanical parameters between some mutants and their respective parental lines showed that mutations in genes responsible for root hair development had no effect on the agrobotanical performance of plants that were grown under controlled conditions. The presented mutant collection is a valuable tool for further identification of genes controlling root hair development in barley