Root branching Dotaz Zobrazit nápovědu
Natural cytokinins as well as the majority of their synthetic derivatives show negative effects on root growth and development. Changes in morphology, primarily linked to the inhibition of the cell division in the meristematic zone, are manifested as thickening and shortening of the primary root and impaired lateral root branching. Rational design of cytokinin derivatives can partially overcome these drawbacks and reduce the negative effects. Using our database of cytokinin derivatives, we selected several aromatic cytokinin analogs with modifications at the N9 atom of the adenine moiety. We found that tetrahydropyranyl and tetrahydrofuranyl substitutions at the N9 atom led to enhanced acropetal transport of the modified cytokinin, and both derivatives also showed weak anticytokinin activity. Consequently, changes in the distribution of the active cytokinin pool together with gradual metabolic conversion of the modified cytokinin to its free form prevent root growth inhibition that limits cytokinin utilization in micropropagation techniques.
Efficient soil exploration by roots represents an important target for crop improvement and food security [1, 2]. Lateral root (LR) formation is a key trait for optimizing soil foraging for crucial resources such as water and nutrients. Here, we report an adaptive response termed xerobranching, exhibited by cereal roots, that represses branching when root tips are not in contact with wet soil. Non-invasive X-ray microCT imaging revealed that cereal roots rapidly repress LR formation as they enter an air space within a soil profile and are no longer in contact with water. Transcript profiling of cereal root tips revealed that transient water deficit triggers the abscisic acid (ABA) response pathway. In agreement with this, exogenous ABA treatment can mimic repression of LR formation under transient water deficit. Genetic analysis in Arabidopsis revealed that ABA repression of LR formation requires the PYR/PYL/RCAR-dependent signaling pathway. Our findings suggest that ABA acts as the key signal regulating xerobranching. We conclude that this new ABA-dependent adaptive mechanism allows roots to rapidly respond to changes in water availability in their local micro-environment and to use internal resources efficiently.
- MeSH
- adaptace psychologická fyziologie MeSH
- Arabidopsis genetika MeSH
- geneticky modifikované rostliny MeSH
- jedlá semena růst a vývoj metabolismus MeSH
- kořeny rostlin metabolismus MeSH
- kyselina abscisová metabolismus MeSH
- meristém metabolismus MeSH
- organogeneze rostlin MeSH
- proteiny huseníčku genetika metabolismus MeSH
- regulace genové exprese u rostlin genetika MeSH
- regulátory růstu rostlin metabolismus MeSH
- signální transdukce MeSH
- transkripční faktory metabolismus MeSH
- voda metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: When applied to a nutrition solution or agar media, the non-substituted aromatic cytokinins caused thickening and shortening of the primary root, had an inhibitory effect on lateral root branching, and even showed some negative effects on development of the aerial part at as low as a 10 nanomolar concentration. Novel analogues of aromatic cytokinins ranking among topolins substituted on N9-atom of adenine by tetrahydropyranyl or 4-chlorobutyl group have been prepared and tested in standardized cytokinin bioassays [1]. Those showing comparable activities with N(6)-benzylaminopurine were further tested in planta. METHODOLOGY/PRINCIPAL FINDINGS: The main aim of the study was to explain molecular mechanism of function of novel cytokinin derivatives on plant development. Precise quantification of cytokinin content and profiling of genes involved in cytokinin metabolism and perception in treated plants revealed several aspects of different action of m-methoxytopolin base and its substituted derivative on plant development. In contrast to standard cytokinins, N9- tetrahydropyranyl derivative of m-topolin and its methoxy-counterpart showed the negative effects on root development only at three orders of magnitude higher concentrations. Moreover, the methoxy-derivative demonstrates a positive effect on lateral root branching and leaf emerging in a nanomolar range of concentrations, in comparison with untreated plants. CONCLUSIONS/SIGNIFICANCE: Tetrahydropyranyl substitution at N9-position of cytokinin purine ring significantly enhances acropetal transport of a given cytokinins. Together with the methoxy-substitution, impedes accumulation of non-active cytokinin glucoside forms in roots, allows gradual release of the active base, and has a significant effect on the distribution and amount of endogenous isoprenoid cytokinins in different plant tissues. The utilization of novel aromatic cytokinin derivatives can distinctively improve expected hormonal effects in plant propagation techniques in the future.
- MeSH
- aktivace enzymů MeSH
- Arabidopsis účinky léků genetika růst a vývoj metabolismus MeSH
- biomasa MeSH
- cytokininy chemie farmakologie MeSH
- kořeny rostlin chemie účinky léků růst a vývoj MeSH
- kukuřice setá účinky léků genetika růst a vývoj metabolismus MeSH
- listy rostlin chemie účinky léků růst a vývoj MeSH
- oxidoreduktasy metabolismus MeSH
- proliferace buněk účinky léků MeSH
- regulace genové exprese u rostlin MeSH
- regulátory růstu rostlin chemie farmakologie MeSH
- semenáček účinky léků MeSH
- stanovení celkové genové exprese MeSH
- xylém chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Formins are evolutionarily conserved eukaryotic proteins engaged in actin nucleation and other aspects of cytoskeletal organization. Angiosperms have two formin clades with multiple paralogs; typical plant Class I formins are integral membrane proteins that can anchor cytoskeletal structures to membranes. For the main Arabidopsis housekeeping Class I formin, FH1 (At3g25500), plasmalemma localization was documented in heterologous expression and overexpression studies. We previously showed that loss of FH1 function increases cotyledon epidermal pavement cell shape complexity via modification of actin and microtubule organization and dynamics. Here, we employ transgenic Arabidopsis expressing green fluorescent protein-tagged FH1 (FH1-GFP) from its native promoter to investigate in vivo behavior of this formin using advanced microscopy techniques. The fusion protein is functional, since its expression complements the fh1 loss-of-function mutant phenotype. Accidental overexpression of FH1-GFP results in a decrease in trichome branch number, while fh1 mutation has the opposite effect, indicating a general role of this formin in controlling cell shape complexity. Consistent with previous reports, FH1-GFP associates with membranes. However, the protein exhibits surprising actin- and secretory pathway-dependent dynamic localization and relocates between cellular endomembranes and the plasmalemma during cell division and differentiation in root tissues, with transient tonoplast localization at the transition/elongation zones border. FH1-GFP also accumulates in actin-rich regions of cortical cytoplasm and associates with plasmodesmata in both the cotyledon epidermis and root tissues. Together with previous reports from metazoan systems, this suggests that formins might have a shared (ancestral or convergent) role at cell-cell junctions.
OBJECTIVE: The aortic arch (AA) is the main conduit of the left side of the heart, providing a blood supply to the head, neck, and upper limbs. As it travels through the thorax, the pattern in which it gives off the branches to supply these structures can vary. Variations of these branching patterns have been studied; however, a study providing a comprehensive incidence of these variations has not yet been conducted. The objective of this study was to perform a meta-analysis of all the studies that report prevalence data on AA variants and to provide incidence data on the most common variants. METHODS: A systematic search of online databases including PubMed, Embase, Scopus, ScienceDirect, Web of Science, SciELO, BIOSIS, and CNKI was performed for literature describing incidence of AA variations in adults. Studies including prevalence data on adult patients or cadavers were collected and their data analyzed. RESULTS: A total of 51 articles were included (N = 23,882 arches). Seven of the most common variants were analyzed. The most common variants found included the classic branching pattern, defined as a brachiocephalic trunk, a left common carotid, and a left subclavian artery (80.9%); the bovine arch variant (13.6%); and the left vertebral artery variant (2.8%). Compared by geographic data, bovine arch variants were noted to have a prevalence as high as 26.8% in African populations. CONCLUSIONS: Although patients who have an AA variant are often asymptomatic, they compose a significant portion of the population of patients and pose a greater risk of hemorrhage and ischemia during surgery in the thorax. Because of the possibility of encountering such variants, it is prudent for surgeons to consider potential variations in planning procedures, especially of an endovascular nature, in the thorax.
- MeSH
- aneurysma diagnostické zobrazování epidemiologie MeSH
- aorta thoracica abnormality diagnostické zobrazování MeSH
- arteria subclavia abnormality diagnostické zobrazování MeSH
- arteria vertebralis abnormality diagnostické zobrazování MeSH
- arteriae carotides abnormality diagnostické zobrazování MeSH
- černoši MeSH
- incidence MeSH
- kardiovaskulární abnormality diagnostické zobrazování epidemiologie MeSH
- lidé MeSH
- prevalence MeSH
- prognóza MeSH
- truncus brachiocephalicus abnormality diagnostické zobrazování MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
An alteration in the structural arrangement of blood vessels identified by RECA immunohistochemistry was studied in a rat L4 dorsal root ganglia (L4-DRG) neuropathic pain model. We compared a three-dimensional (3-D) reconstruction of the vascular architecture surrounding bodies of the primary sensory neurons in the L4-DRG of naïve rats with that of rats that had surgically undergone unilateral sciatic nerve ligature. Rhodamine-conjugated dextran (Fluoro-Ruby) was used for retrograde labelling of neurons, the axons of which had been injured by nerve ligature. In contrast to DRG from naïve rats and contralateral DRG from operated rats, an increased proportion of RECA+ vascular area and the appearance of nest-like arrangements of blood vessels around neuronal bodies with injured axons were observed in L4-DRG ipsilateral to the sciatic nerve ligature. Fractal analysis confirmed a higher degree of vascular branching, irregularity, and tortuosity in L4-DRG related with sciatic nerve injury. The results suggest that nerve injury induces changes in vascular architecture in associated DRG.
- MeSH
- cévy inervace patofyziologie MeSH
- funkční lateralita MeSH
- hyperalgezie patofyziologie MeSH
- krysa rodu rattus MeSH
- nemoci periferního nervového systému patofyziologie MeSH
- nervové receptory cytologie patologie fyziologie MeSH
- nervus ischiadicus patofyziologie MeSH
- neurony fyziologie MeSH
- počítačové zpracování obrazu MeSH
- potkani Wistar MeSH
- spinální ganglia anatomie a histologie krevní zásobení MeSH
- Wallerova degenerace patofyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Uncontrolled bleeding post root, ascending aorta and aortic arch operations can occur. Various techniques for getting bleeding under control have already been published in the literature. This life-threatening complication happens especially during acute aortic dissection and acute endocarditis operations, the former sometimes requiring complex mobilization of the aortic arch and the use of branched prosthetic grafts. In this report we describe the simple innovation of the technique which creates a relatively small space surrounding the aortic graft by its wrapping with use of the pericardium. Decompression of this space is maintained to a low-pressure system.
- MeSH
- aorta thoracica chirurgie MeSH
- aorta chirurgie MeSH
- aortální aneurysma chirurgie radiografie MeSH
- cévy - implantace protéz škodlivé účinky MeSH
- chirurgická dekomprese MeSH
- disekce aorty chirurgie radiografie MeSH
- endokarditida chirurgie radiografie MeSH
- hemostáza chirurgická metody MeSH
- lidé MeSH
- perikard chirurgie MeSH
- počítačová rentgenová tomografie MeSH
- pooperační krvácení etiologie prevence a kontrola MeSH
- tlak MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
Ericaceae (the heath family) are widely distributed calcifuges inhabiting soils with inherently poor nutrient status. Ericaceae overcome nutrient limitation through symbiosis with ericoid mycorrhizal (ErM) fungi that mobilize nutrients complexed in recalcitrant organic matter. At present, recognized ErM fungi include a narrow taxonomic range within the Ascomycota, and the Sebacinales, basal Hymenomycetes with unclamped hyphae and imperforate parenthesomes. Here we describe a novel type of basidiomycetous ErM symbiosis, termed 'sheathed ericoid mycorrhiza', discovered in two habitats in mid-Norway as a co-dominant mycorrhizal symbiosis in Vaccinium spp. The basidiomycete forming sheathed ErM possesses clamped hyphae with perforate parenthesomes, produces 1- to 3-layer sheaths around terminal parts of hair roots and colonizes their rhizodermis intracellularly forming hyphal coils typical for ErM symbiosis. Two basidiomycetous isolates were obtained from sheathed ErM and molecular and phylogenetic tools were used to determine their identity; they were also examined for the ability to form sheathed ErM and lignocellulolytic potential. Surprisingly, ITS rDNA of both conspecific isolates failed to amplify with the most commonly used primer pairs, including ITS1 and ITS1F + ITS4. Phylogenetic analysis of nuclear LSU, SSU and 5.8S rDNA indicates that the basidiomycete occupies a long branch residing in the proximity of Trechisporales and Hymenochaetales, but lacks a clear sequence relationship (>90% similarity) to fungi currently placed in these orders. The basidiomycete formed the characteristic sheathed ErM symbiosis and enhanced growth of Vaccinium spp. in vitro, and degraded a recalcitrant aromatic substrate that was left unaltered by common ErM ascomycetes. Our findings provide coherent evidence that this hitherto undescribed basidiomycete forms a morphologically distinct ErM symbiosis that may occur at significant levels under natural conditions, yet remain undetected when subject to amplification by 'universal' primers. The lignocellulolytic assay suggests the basidiomycete may confer host adaptations distinct from those provisioned by the so far investigated ascomycetous ErM fungi.
- MeSH
- Basidiomycota genetika MeSH
- Ericaceae mikrobiologie MeSH
- fylogeneze MeSH
- kořeny rostlin mikrobiologie MeSH
- mykorhiza klasifikace genetika MeSH
- symbióza genetika MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Norsko MeSH
Background and Aims: Root absorptive characteristics rely on the presence of apoplastic barriers. However, little is known about the establishment of these barriers within a complex root system, particularly in a major portion of them - the lateral roots. In Zea mays L., the exodermis differentiates under the influence of growth conditions. Therefore, the species presents a suitable model to elucidate the cross-talk among environmental conditions, branching pattern and the maturation of barriers within a complex root system involved in the definition of the plant-soil interface. The study describes the extent to which lateral roots differentiate apoplastic barriers in response to changeable environmental conditions. Methods: The branching, permeability of the outer cell layers and differentiation of the endo- and exodermis were studied in primary roots and various laterals under different types of stress of agronomic importance (salinity, heavy metal toxicity, hypoxia, etc.). Histochemical methods, image analysis and apoplastic tracer assays were utilized. Key Results: The results show that the impact of growth conditions on the differentiation of both the endodermis and exodermis is modulated according to the type/diameter of the root. Fine laterals clearly represent that portion of a complex root system with a less advanced state of barrier differentiation, but with substantial ability to modify exodermis differentiation in response to environmental conditions. In addition, some degree of autonomy in exodermal establishment of Casparian bands (CBs) vs. suberin lamellae (SLs) was observed, as the absence of lignified exodermal CBs did not always fit with the lack of SLs. Conclusions: This study highlights the importance of lateral roots, and provides a first look into the developmental variations of apoplastic barriers within a complex root system. It emphasizes that branching and differentiation of barriers in fine laterals may substantially modulate the root system-rhizosphere interaction.
INTRODUCTION: The anatomy of the brachial plexus has been a subject of interest to many researchers over time resulting in an inconsistent amount of data. Previously, our team had published two evidence-based studies on the anatomical variations involving the brachial plexus, therefore the aim of this study was to analyze the findings regarding the infraclavicular part of the brachial plexus with the use of meta-analytic techniques to complete the comprehensive series. MATERIAL AND METHODS: Major scientific databases were extensively searched to compile anatomical studies investigating the morphology of the infraclavicular part of the brachial plexus. Extracted data were classified based on our proposed classification system and subsequently analyzed with the use of random effects meta-analysis to state the pooled prevalence estimates of the distinct variation patterns. RESULTS: A total of 75 studies (4772 upper limbs) were selected for the meta-analysis. The branches of the lateral cord, including the lateral pectoral nerve and musculocutaneous nerve, resembled their usual origin in 76.8% (95% CI 50-96%) and 98.8% (95% CI 98-100%), respectively. The medial pectoral nerve, medial brachial cutaneous nerves, medial antebrachial cutaneous nerve and ulnar nerve emerging from the medial cord were observed originating from their usual origins in 90.9% (95% CI 68-100%), 90.7% (95% CI 73-100%), 87.9% (95% CI 67-99%) and 97.7% (95% CI 94-100%), respectively. Lastly, nerves branching from the posterior cord, including the superior and inferior subscapular nerves, thoracodorsal nerve, axillary nerve and radial nerve, originated as per textbook description in 90.7% (95% CI 80-98%), 76.1% (95% CI 61-89%), 90.1% (95% CI 84-95%), 79.8% (95% CI 68-90%) and 99.0% (95% CI 96-100%), respectively. Moreover, the usual origin of the median nerve from the lateral and medial cord via the corresponding roots was encountered in 89.7% (95% CI 84-95%) of cases. CONCLUSIONS: The nerves originating from the infraclavicular part of the brachial plexus exhibit a wide spectrum of possible origins. However, the usual patterns were significantly the most common types present in more than three quarters of cases. Especially clinicians might profit from the enhanced understanding of the brachial plexus anatomy presented herein, since we offer a strong guide for handling the anatomically challenging pathologies in this specific area.
