Cu+ -chaperones are a diverse group of proteins that allocate Cu+ ions to specific copper proteins, creating different copper pools targeted to specific physiological processes. Symbiotic nitrogen fixation carried out in legume root nodules indirectly requires relatively large amounts of copper, for example for energy delivery via respiration, for which targeted copper deliver systems would be required. MtNCC1 is a nodule-specific Cu+ -chaperone encoded in the Medicago truncatula genome, with a N-terminus Atx1-like domain that can bind Cu+ with picomolar affinities. MtNCC1 is able to interact with nodule-specific Cu+ -importer MtCOPT1. MtNCC1 is expressed primarily from the late infection zone to the early fixation zone and is located in the cytosol, associated with plasma and symbiosome membranes, and within nuclei. Consistent with its key role in nitrogen fixation, ncc1 mutants have a severe reduction in nitrogenase activity and a 50% reduction in copper-dependent cytochrome c oxidase activity. A subset of the copper proteome is also affected in the ncc1 mutant nodules. Many of these proteins can be pulled down when using a Cu+ -loaded N-terminal MtNCC1 moiety as a bait, indicating a role in nodule copper homeostasis and in copper-dependent physiological processes. Overall, these data suggest a pleiotropic role of MtNCC1 in copper delivery for symbiotic nitrogen fixation.

• Klíčová slova
• copper, copper transport, metallochaperone, nitrogen fixation, nodulation,
• MeSH
• fixace dusíku * genetika   MeSH
• kořenové hlízky rostlin metabolismus   MeSH
• měď metabolismus   MeSH
• Medicago truncatula * genetika   metabolismus   MeSH
• rostlinné proteiny genetika   metabolismus   MeSH
• symbióza fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• měď MeSH
• rostlinné proteiny MeSH

INTRODUCTION: The study compares the results of open reduction using volar locking plates with ligamentotaxis by external fixation in fractures of distal radius type 2R3C according to AO classification. METHODS: A retrospective study evaluating the results of osteosynthesis in patients with distal radius fractures type 2R3C according to AO classification, operated until December 2018. The ORIF method with volar locking plates (LCP) was used in 54 patients, and closed reduction with ligamentotaxis using external fixation (EF) was used in 33 patients. The mean age of the patients was 46.7 years in the LCP group and 59.6 years in the EF group. All were evaluated for their X-ray and functional outcomes and according to the Green and OBrien score at 6 and 12 months after surgery. Results: According to X-rays at 12 months in the LCP group, the mean sagittal tilt was 10.13°, the mean radial inclination was 23.89°, and the mean radial length was 11.84 mm. In the EF group, the mean sagittal tilt was 6.32°, the mean radial inclination was 24.78°, and the mean radial length was 9.89 mm. According to the Green and OBrien score, we recorded a mean score of 84.44 points in the LCP group at 12 month; we achieved good and excellent results in 83.33% of the patients and no poor result was observed. In the EF group the final mean score was 77.27; good and excellent results were achieved in 45.46% of the patients and a poor result in one patient. CONCLUSION: Based on the results in our group of patients, the internal type osteosynthesis using LCP implants can be recommended as a first-choice technique in the treatment of 2R3C fractures according to AO classification.

• Klíčová slova
• distal radius fracture − external fixation − open reduction − internal fixation − volar locking plate,
• MeSH
• fixace fraktury MeSH
• fraktury vřetenní kosti * diagnostické zobrazování   chirurgie   MeSH
• kostní destičky MeSH
• lidé středního věku MeSH
• lidé MeSH
• radius * diagnostické zobrazování   chirurgie   MeSH
• retrospektivní studie MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Biological nitrogen fixation is a key driver of global primary production and climate. Decades of effort have repeatedly updated nitrogen fixation estimates for terrestrial and open ocean systems, yet other aquatic systems in between have largely been ignored. Here we present an evaluation of nitrogen fixation for inland and coastal waters. We demonstrate that water column and sediment nitrogen fixation is ubiquitous across these diverse aquatic habitats, with rates ranging six orders of magnitude. We conservatively estimate that, despite accounting for less than 10% of the global surface area, inland and coastal aquatic systems fix 40 (30 to 54) teragrams of nitrogen per year, equivalent to 15% of the nitrogen fixed on land and in the open ocean. Inland systems contribute more than half of this biological nitrogen fixation.

• MeSH
• dusík metabolismus   MeSH
• ekosystém * MeSH
• fixace dusíku * MeSH
• geologické sedimenty chemie   mikrobiologie   MeSH
• mořská voda * mikrobiologie   chemie   MeSH
• oceány a moře MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• oceány a moře MeSH
• Názvy látek
• dusík MeSH

Crocosphaera is a major dinitrogen (N2)-fixing microorganism, providing bioavailable nitrogen (N) to marine ecosystems. The N2-fixing enzyme nitrogenase is deactivated by oxygen (O2), which is abundant in marine environments. Using a cellular scale model of Crocosphaera sp. and laboratory data, we quantify the role of three O2 management strategies by Crocosphaera sp.: size adjustment, reduced O2 diffusivity, and respiratory protection. Our model predicts that Crocosphaera cells increase their size under high O2 Using transmission electron microscopy, we show that starch granules and thylakoid membranes are located near the cytoplasmic membranes, forming a barrier for O2 The model indicates a critical role for respiration in protecting the rate of N2 fixation. Moreover, the rise in respiration rates and the decline in ambient O2 with temperature strengthen this mechanism in warmer water, providing a physiological rationale for the observed niche of Crocosphaera at temperatures exceeding 20°C. Our new measurements of the sensitivity to light intensity show that the rate of N2 fixation reaches saturation at a lower light intensity (∼100 μmol m-2 s-1) than photosynthesis and that both are similarly inhibited by light intensities of >500 μmol m-2 s-1 This suggests an explanation for the maximum population of Crocosphaera occurring slightly below the ocean surface.IMPORTANCECrocosphaera is one of the major N2-fixing microorganisms in the open ocean. On a global scale, the process of N2 fixation is important in balancing the N budget, but the factors governing the rate of N2 fixation remain poorly resolved. Here, we combine a mechanistic model and both previous and present laboratory studies of Crocosphaera to quantify how chemical factors such as C, N, Fe, and O2 and physical factors such as temperature and light affect N2 fixation. Our study shows that Crocosphaera combines multiple mechanisms to reduce intracellular O2 to protect the O2-sensitive N2-fixing enzyme. Our model, however, indicates that these protections are insufficient at low temperature due to reduced respiration and the rate of N2 fixation becomes severely limited. This provides a physiological explanation for why the geographic distribution of Crocosphaera is confined to the warm low-latitude ocean.

• Klíčová slova
• Crocosphaera, carbon, cell flux model, daily cycle, iron, light, nitrogen, nitrogen fixation, oxygen, photosynthesis, temperature,
• MeSH
• fixace dusíku * MeSH
• kyslík metabolismus   MeSH
• sinice cytologie   metabolismus   účinky záření   MeSH
• škrob metabolismus   MeSH
• světlo * MeSH
• teplota * MeSH
• transmisní elektronová mikroskopie MeSH
• tylakoidy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• kyslík MeSH
• škrob MeSH

The experience is summarized in using the method of external fixation (Stuhler-Heise from Aesculap, Poldi 7, Ilizarov's compressory distractive devices) in the traumatology of extremities within 5-year lasting period. Starting from june 1985 to July 1990, the amount of 90 open fractures of long bones has been managed (10.2% of all fractures admitted). Open fractures related to III. grade by Gustilo's classification were 20 in number, i.e. 22.0% of all open fractures admitted with anatomical distribution as follows: 50% crural, 25% humeral, 15% forearm and 10% femoral locations. The EF device was applied in 11 cases, i.e. 55%. Primary amputations were done in 4 cases, i.e. 20%. The EF application period averaged for 64 days. One case showed primary healing of EF treated fractures. The remaining cases attributed an exchange of the type of osteosynthesis or were supplemented with plastic surgery on the soft tissues and bone. Another group of 36 pseudoarthroses of long bones were operated on within the mentioned period, from them 9 cases as infected ones were treated with EF method. Once the infection has been healed, the authors proceeded with surgery and EF exchange in all cases when treating pseudoarthroses. Third--the group of 18 nonstabile intraarticular fractures of distal radius treated by means of EF is presented. The advantages of individual EF methods are discussed, and the comprehensive care approaches are presented in documental groups of injuries as illustrated with the short case-reports.

• MeSH
• externí fixátory * MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND AND AIMS: Rootless carnivorous plants of the genus Utricularia are important components of many standing waters worldwide, as well as suitable model organisms for studying plant-microbe interactions. In this study, an investigation was made of the importance of microbial dinitrogen (N2) fixation in the N acquisition of four aquatic Utricularia species and another aquatic carnivorous plant, Aldrovanda vesiculosa. METHODS: 16S rRNA amplicon sequencing was used to assess the presence of micro-organisms with known ability to fix N2. Next-generation sequencing provided information on the expression of N2 fixation-associated genes. N2 fixation rates were measured following (15)N2-labelling and were used to calculate the plant assimilation rate of microbially fixed N2. KEY RESULTS: Utricularia traps were confirmed as primary sites of N2 fixation, with up to 16 % of the plant-associated microbial community consisting of bacteria capable of fixing N2. Of these, rhizobia were the most abundant group. Nitrogen fixation rates increased with increasing shoot age, but never exceeded 1·3 μmol N g(-1) d. mass d(-1). Plant assimilation rates of fixed N2 were detectable and significant, but this fraction formed less than 1 % of daily plant N gain. Although trap fluid provides conditions favourable for microbial N2 fixation, levels of nif gene transcription comprised <0·01 % of the total prokaryotic transcripts. CONCLUSIONS: It is hypothesized that the reason for limited N2 fixation in aquatic Utricularia, despite the large potential capacity, is the high concentration of NH4-N (2·0-4·3 mg L(-1)) in the trap fluid. Resulting from fast turnover of organic detritus, it probably inhibits N2 fixation in most of the microorganisms present. Nitrogen fixation is not expected to contribute significantly to N nutrition of aquatic carnivorous plants under their typical growth conditions; however, on an annual basis the plant-microbe system can supply nitrogen in the order of hundreds of mg m(-2) into the nutrient-limited littoral zone, where it may thus represent an important N source.

• Klíčová slova
• 15N2 labelling, Aldrovanda vesiculosa, N nutrition, U. australis, U. intermedia, U. reflexa, Utricularia vulgaris, aquatic carnivorous plants, daily nitrogen gain, nitrogen fixation, periphyton, traps,
• MeSH
• amoniové sloučeniny analýza   MeSH
• Bacteria genetika   izolace a purifikace   metabolismus   MeSH
• bakteriální RNA chemie   genetika   MeSH
• Droseraceae metabolismus   mikrobiologie   MeSH
• dusík metabolismus   MeSH
• ekologie MeSH
• ekosystém MeSH
• fixace dusíku * MeSH
• izotopy dusíku MeSH
• Magnoliopsida metabolismus   mikrobiologie   MeSH
• molekulární sekvence - údaje MeSH
• RNA ribozomální 16S chemie   genetika   MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza RNA MeSH
• voda metabolismus   MeSH
• výhonky rostlin metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• amoniové sloučeniny MeSH
• bakteriální RNA MeSH
• dusík MeSH
• izotopy dusíku MeSH
• RNA ribozomální 16S MeSH
• voda MeSH

High-resolution analysis of tubulin structure and docking the structure of tubulin dimer into a map of microtubules led to a prediction that sites for tubulin acetylation are in the interior of microtubules. This is somehow difficult to reconcile with their susceptibility to proteases and acetylation in assembled microtubules. To assess the availability of acetylated alpha-tubulin for antibodies, immunofluorescence on detergent-extracted cells, on cells fixed under various conditions and in microinjected cells was performed with monoclonal antibodies of known epitope locations. The presented data indicate that acetylated alpha:Lys40 is not exposed on unfixed microtubules but that this region of lumenal microtubule surface becomes easily exposed under mild fixation conditions.

• MeSH
• acetylace MeSH
• buňky 3T3 MeSH
• fixace tkání MeSH
• mikrotubuly metabolismus   MeSH
• myši MeSH
• tubulin metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• tubulin MeSH

Osteoradionecrosis of the jaw can be treated using both conservative treatment and surgery. External fixation may be used to bridge large resection defects after sequestrectomy for stabilisation and before secondary mandibular reconstruction. We designed a retrospective analysis of 70 patients with osteoradionecrosis treated between the years 2014 and 2018, and found that the use of external fixation greatly improves their outcomes. Patients were grouped according to Notani's classification: those who had Notani I disease were treated surgically but without external fixation; and those with Notani II and Notani III disease were eligible for external fixation. In those with Notani II disease, there was a significant reduction in the number of pathological fractures that occurred with external fixation. In those with Notani III disease, the success rate of primary sequestrectomy was only 1:14; however, those treated with external fixation all successfully healed after their first operation. It was hypothesised that although external fixation would improve outcome, it would come at a detriment to their quality of life (QoL). However, in a subset of these patients, we showed that in addition to increasing successful healing, patients' QoL with the external fixator was no worse than when they had an active osteonecrotic lesion. The treatment of osteoradionecrosis is cumbersome and advanced stages are associated with more complications. The use of an external fixator significantly reduces the probability of pathological fractures and increases the rate of successful healing in patients after mandibular resection. It does this without greatly interfering with patients' lives, while improving their condition sufficiently to allow for subsequent mandibular reconstruction.

• Klíčová slova
• Notani classification, Osteoradionecrosis, external fixation, head and neck cancer, healing, lesion, necrosis of the jaw, pathological fractures, quality of life, reconstruction, sequestrectomy,
• MeSH
• externí fixátory MeSH
• fixace fraktury MeSH
• kvalita života * MeSH
• lidé MeSH
• osteoradionekróza * chirurgie   MeSH
• retrospektivní studie MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVES: To recommend appropriate immobilization after the initial reduction of acetabular displaced fractures in order to minimize the risk of heterotopic ossification formation. DESIGN: Retrospective study of patients treated in our surgical department during the years 2005-2018. MATERIALS AND METHODS: There were 94 patients included in statistical analysis. The factors of injury severity, course of surgery and hospitalization and incidence of complications were recorded. The functional and X-ray results were evaluated at least one year after surgery. RESULTS: The patients were divided into the two groups according to the type of fixation after closed reduction, the external fixation (EF) and the skeletal traction (ST) group. According to the type of fracture there were 33 patients with central displacement and 61 patients with posterior displacement. Ossification grade III. And IV. Occur in 20% of our sample. There was greater incidence of Brooker grade III. And IV. Ossification in the ST group, but statistically insignificant, p = 0.57. There was no statistically significant difference in the occurrence of ossifications regarding the severity of the head injury, p = 0.11, or to the severity of the injury p = 0.54. The combination of posterior displacement and ST results in higher risk for ossifications, specifically in our group at 11.48% compared to the combination of posterior displacement and EF where it is 8.2%. CONCLUSION: Skeletal traction for posterior displaced acetabular fracture appears to be a more risky procedure for the development of ossifications than external fixation.

• MeSH
• acetabulum zranění   chirurgie   MeSH
• externí fixátory * škodlivé účinky   MeSH
• fixace fraktury škodlivé účinky   MeSH
• heterotopická osifikace * epidemiologie   etiologie   prevence a kontrola   MeSH
• lidé MeSH
• retrospektivní studie MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

In situ nitrogen fixation was investigated in a cyanobacterial mat growing on the bed of rocks of the Muga River, Spain. The filamentous non-heterocystous cyanobacterium Schizothrix dominated the mat, showing nitrogenase activity in the light at similar rates to those found in nearby heterocystous Rivularia colonies. N2 fixation in the light was significantly increased by an inhibitor of PSII and oxygen evolution, DCMU (3-[3,4-dichlorophenyl]-1,1-dimethylurea), and anaerobic conditions. However, no nitrogenase activity was found in the dark. Addition of fructose as a respiratory substrate induced nitrogenase activity in samples incubated under aerobic conditions in the dark but not in anaerobic conditions. Microelectrode oxygen profiles showed internal microaerobic microzones where nitrogen fixation might concentrate. Analyses of the 16S rRNA gene revealed only the presence of sequences belonging to filamentous non-heterocystous cyanobacteria. nifH gene diversity showed that the major phylotypes also belonged to this group. One of the three strains isolated from the Schizothrix mat was capable of fixing N2 and growing in the absence of combined N. This was consistent with the nifH gene analysis. These results suggest a relevant contribution of non-heterocystous cyanobacteria to nitrogen fixation in these mats.

• MeSH
• DNA bakterií genetika   MeSH
• fixace dusíku fyziologie   MeSH
• fylogeneze MeSH
• nitrogenasa metabolismus   MeSH
• řeky MeSH
• RNA ribozomální 16S genetika   MeSH
• sinice genetika   izolace a purifikace   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA bakterií MeSH
• nitrogenasa MeSH
• RNA ribozomální 16S MeSH