The Occurrence of Peroxiredoxins and Changes in Redox State in Acer platanoides and Acer pseudoplatanus During Seed Development

Ratajczak E, Dietz K-J, Kalemba EM. The Occurrence of Peroxiredoxins and Changes in Redox State in Acer platanoides and Acer pseudoplatanus During Seed Development. JOURNAL OF PLANT GROWTH REGULATION. 2019;38(1):298-314.Norway maple (Acer platanoides L.) and sycamore (A. pseudoplatanus L.) are genetically closely related species that produce desiccation-tolerant (orthodox) and desiccation-sensitive (recalcitrant) seeds, respectively. Norway maple and sycamore seeds were analyzed during their development from the 14th to 24th weeks after flowering (WAF) and 11th to 21st WAF, respectively, to explore redox-related biochemical properties related to their contrasting physiology. Selected similar stages of seed development were characterized during the course of gradual decreasing water content in both seed types. The levels of protein and non-protein thiols peaked at the 18th WAF in Norway maple embryonic axes, whereas these levels constantly increased in maturing sycamore seeds. The glutathione half-cell reduction potential revealed that the cell environment adopted a more oxidized state in sycamore seeds. Peroxiredoxins (Prxs), including cytosolic/nuclear 1-Cys-Prx, cytosolic PrxIIC, mitochondrial PrxIIE, and plastidic PrxIIF, 2-Cys-Prx, and PrxQ, were detected in both species, but Norway maple embryonic axes contained higher levels of PrxIIC and PrxIIE, two Prxs with the highest peroxide detoxification potential in Arabidopsis. Redox proteomics revealed that 2-Cys-Prx was present in reduced form in both species, whereas 1-Cys-Prx was reduced uniquely in Norway maple seeds. Several enzymes, including glucose and ribitol dehydrogenase as well as fructose-bisphosphate aldolase, were oxidation-sensitive at all developmental stages in sycamore embryonic axes. Redox signaling as manifested by reactive oxygen species signals, and the oxidation of protein thiols to disulfides are discussed with respect to their significance in determining orthodox or recalcitrant seed characteristics

Clinical application of a rapid microbiological test based on capillary zone electrophoresis to assess local skin infection

<p>Abstract</p> <p>Background</p> <p>The basic clinical problem associated with infection treatment is the fact that classic, commonly and routinely used isolation and identification methods are based on long-term processes of a phenotypic analysis of microorganisms. Consequently sometimes, especially in small centres, rapid implementation of antibacterial treatment becomes delayed.</p> <p>The work presents the initial results of rapid microbiological identification based on an original method of capillary zone electrophoresis (CZE). The study involved the analysis of 78 biological samples from post-operative wounds and trophic ulcers.</p> <p>Results</p> <p>The attempt was made to identify individual bacterial species based on characteristic features of electropherograms achieved. Finally, G(+) cocci type bacteria and different G(-) rods were identified with sensitivity of 88.1% and specificity of 100%.</p> <p>Conclusions</p> <p>Based on the clinical trials using an electrophoretic technique in the field of microbiological diagnostics of infected exudate from a post-operative wound it can be concluded that it is a rapid and relatively sensitive method for initial identification of infectious pathogens.</p

Regulation of Gene Expression of Methionine Sulfoxide Reductases and Their New Putative Roles in Plants

Oxidation of methionine to methionine sulfoxide is a type of posttranslational modification reversed by methionine sulfoxide reductases (Msrs), which present an exceptionally high number of gene copies in plants. The side-form general antioxidant function-specific role of each Msr isoform has not been fully studied. Thirty homologous genes of Msr type A (MsrA) and type B (MsrB) that originate from the genomes of Arabidopsis thaliana, Populus trichocarpa, and Oryza sativa were analyzed in silico. From 109 to 201 transcription factors and responsive elements were predicted for each gene. Among the species, 220 and 190 common transcription factors and responsive elements were detected for the MsrA and MsrB isoforms, respectively. In a comparison of 14 MsrA and 16 MsrB genes, 424 transcription factors and responsive elements were reported in both types of genes, with almost ten times fewer unique elements. The transcription factors mainly comprised plant growth and development regulators, transcription factors important in stress responses with significant overrepresentation of the myeloblastosis viral oncogene homolog (MYB) and no apical meristem, Arabidopsis transcription activation factor and cup-shaped cotyledon (NAC) families and responsive elements sensitive to ethylene, jasmonate, sugar, and prolamine. Gene Ontology term-based functional classification revealed that cellular, metabolic, and developmental process terms and the response to stimulus term dominated in the biological process category. Available experimental transcriptomic and proteomic data, in combination with a set of predictions, gave coherent results validating this research. Thus, new manners Msr gene expression regulation, as well as new putative roles of Msrs, are proposed

Dehydration Sensitivity at the Early Seedling Establishment Stages of the European Beech (Fagus sylvatica L.)

Shortage of water is a limiting factor for the growth and development of plants, particularly at early developmental stages. We focused on the European beech (Fagus sylvatica L.), which produces seeds and further seedlings in large intervals of up to ten years. To explore the beech seedling establishment process, six stages referring to embryo expansion were studied to determine sensitivity to dehydration. The characterization of the response of elongating embryonic axes and cotyledons included a viability test before and after dehydration and measurement of the amounts of electrolyte leakage, concentration, and arrangement of storage materials, changes in chaperone proteins related to water deficit, and accumulation of hydrogen peroxide and superoxide anion radicals. Elongating embryonic axes and cotyledons differed in water content, dehydration rates, membrane permeability before and after dehydration, protein, and lipid decomposition pattern, and amount of 44-kDa dehydrin and 22-kDa small heat shock protein (sHSP). Protruding embryonic axes were more sensitive to dehydration than cotyledons, although dehydration caused transient reinduction of three dehydrin-like proteins and sHSP synthesis, which accompany desiccation tolerance. Extended deterioration, including overproduction of hydrogen peroxide and depletion of superoxide anion radicals, was reported in dehydrated embryonic axes longer than 10 mm characterized by highly elevated cellular leakage. The apical part elongating embryonic axes consisting of the radicles was the most sensitive part of the seed to dehydration, and the root apical meristem area was the first to become inviable. The effects of severe dehydration involving ROS imbalance and reduced viability in beech seedlings with embryonic axes longer than 10 mm might help to explain the difficulties in beech seedling establishment observed in drought-affected environments. The conversion of environmental drought into climate-originated oxidative stress affecting beech seedling performance is discussed in this report

Autophagy counteracts instantaneous cell death during seasonal senescence of the fine roots and leaves in Populus trichocarpa

Abstract Background Senescence, despite its destructive character, is a process that is precisely-regulated. The control of senescence is required to achieve remobilization of resources, a principle aspect of senescence. Remobilization allows plants to recapture valuable resources that would otherwise be lost to the environment with the senescing organ. Autophagy is one of the critical processes that is switched on during senescence. This evolutionarily conserved process plays dual, antagonistic roles. On the one hand, it counteracts instantaneous cell death and allows the process of remobilization to be set in motion, while on the other hand, it participates in the degradation of cellular components. Autophagy has been demonstrated to occur in many plant species during the senescence of leaves and flower petals. Little is known, however, about the senescence process in other ephemeral organs, such as fine roots, whose lifespan is also relatively short. We hypothesized that, like the case of seasonal leaf senescence, autophagy also plays a role in the senescence of fine roots, and that both processes are synchronized in their timing. Results We evaluated which morphological and cytological symptoms are universal or unique in the senescence of fine roots and leaves. The results of our study confirmed that autophagy plays a key role in the senescence of fine roots, and is associated also with the process of cellular components degradation. In both organs, structures related to autophagy were observed, such as autophagic bodies and autophagosomes. The role of autophagy in the senescence of these plant organs was further confirmed by an analysis of ATG gene expression and protein detection. Conclusions The present study is the first one to examine molecular mechanisms associated with the senescence of fine roots, and provide evidence that can be used to determine whether senescence of fine roots can be treated as another example of developmentally programmed cell death (dPCD). Our results indicate that there is a strong similarity between the senescence of fine roots and other ephemeral organs, suggesting that this process occurs by the same autophagy-related mechanisms in all plant ephemeral organs

The involvement of the mitochondrial peroxiredoxin PRXIIF in defining physiological differences between orthodox and recalcitrant seeds of two Acer species

Ratajczak E, Stroeher E, Oelze M-L, Kalemba EM, Pukacka S, Dietz K-J. The involvement of the mitochondrial peroxiredoxin PRXIIF in defining physiological differences between orthodox and recalcitrant seeds of two Acer species. Functional Plant Biology. 2013;40(10):1005-1017.Norway maple (Acer platanoides L., orthodox) and sycamore (Acer pseudoplatanus L., recalcitrant) belong to the same genus and grow under similar climatic conditions, but their seeds differ in their tolerance to desiccation. The initial water content (WC) of the seeds used in this study was 50%, and they were dried to 40, 20 and 7%. The mitochondrial peroxiredoxin IIF (PRXIIF) was identified in seeds of both species by immunoblotting. Semiquantitative RT-PCR analyses indicated that the transcript level of PRXIIF in both types of seeds increased during different stages of desiccation and was higher in seeds of Norway maple than in sycamore. General proteome analyses showed important differences between orthodox and recalcitrant seeds. In sycamore seeds that had been desiccated to a 7% WC, the number of protein spots and the levels of those spots were lower than in desiccation-tolerant Norway maple seeds. Post-translational modifications of PRXIIF in seeds at a 50% WC were detected via 2D electrophoresis and subsequent western blot analysis. The detected shift in the pI values (+/- 0.3) in A. pseudoplatanus was possibly caused by phosphorylation because several potential phosphorylation sites were predicted in silico for that protein. The gene and amino acid sequences were obtained and aligned with known sequences of other plant PRXIIF genes and proteins. High values of sequence identity were noted between the PRXIIF protein sequences of Acer species, Populus trichocarpa Torr. & A. Gray and Arabidopsis thaliana (L.) Heynh. The involvement of PRXIIF in defining the physiological differences between desiccation-tolerant and desiccation-sensitive Acer seeds is discussed in the context of its role in mitochondrial redox homeostasis