Endogenous Production and Vibrational Analysis of Heavy-Isotope-Labeled Peptides from Cyanobacteria.

Stable isotope labeling is an extremely useful tool for characterizing the structure, tracing the metabolism, and imaging the distribution of natural products in living organisms using mass-sensitive measurement techniques. In this study, a cyanobacterium was cultured in 15 N/13 C-enriched media to endogenously produce labeled, bioactive oligopeptides. The extent of heavy isotope incorporation in these peptides was determined with LC-MS, while the overall extent of heavy isotope incorporation in whole cells was studied with nanoSIMS and AFM-IR. Up to 98 % heavy isotope incorporation was observed in labeled cells. Three of the most abundant peptides, microcystin-LR (MCLR), cyanopeptolin-A (CYPA), and aerucyclamide-A (ACAA), were isolated and further studied with Raman and FTIR spectroscopies and DFT calculations. This revealed several IR and Raman active vibrations associated with functional groups not common in ribosomal peptides, like diene, ester, thiazole, thiazoline, and oxazoline groups, which could be suitable for future vibrational imaging studies. More broadly, this study outlines a simple and relatively inexpensive method for producing heavy-labeled natural products. Manipulating the bacterial culture conditions by the addition of specific types and amounts of heavy-labeled nutrients provides an efficient means of producing heavy-labeled natural products for mass-sensitive imaging studies.

Phosphorus retention within a relic agricultural ditch in a constructed wetland.

Stormwater treatment areas (STAs) are constructed wetlands established to capture phosphorus (P) from agricultural runoff before reaching the Florida Everglades. Retained P is primarily stored in wetland soils and sediments generated through a collection of interrelated physical, chemical, and biological processes. The amount of P and other elements (Al, Ca, Cu, Fe, Mg, Mn, Pb, and Zn) retained in the flocculent (floc) and recently accreted soil (RAS) horizons from a relic agricultural ditch within Cell 4S of STA-1E were compared with the surrounding marsh soils (upstream and downstream sites of the ditch). The amount of P retained in the ditch was significantly greater than the surrounding marsh soils and for all the elements in the floc horizon and five of the nine elements in the RAS horizon, suggesting that different processes or process rates influenced accumulation. Phosphorus species in the floc and RAS sediment horizons were identified and quantified using 31 P nuclear magnetic resonance (NMR) spectroscopy and total P determined by microwave plasma-optical emission spectroscopy. In general, P forms were dominated by orthophosphate, sugar phosphates, nucleotides, DNA, and pyrophosphate, with varying relative abundances of species. Total P concentration significantly decreased from upstream to downstream of the ditch by an average of 28 and 35% for floc and RAS soils, respectively. The relatively high P accrual rate within the ditch suggested that relic ditches perpendicular to flow could reduce P transport to downstream soils and sediments and, in turn, help maintain low P levels in overlying water.

The role of rice (Oryza sativa L.) in sequestering phosphorus compounds and trace elements: Speciation and dynamics.

In southern Florida, the sequestering of nutrients through the cultivation of rice (Oryza sativa L.) in alternation with sugarcane (Saccharum spp.) crops is an essential step in minimizing downstream eutrophication of the Florida Everglades. Phosphorus (P) is known to be the leading cause of this eutrophication; however, the cultivation/harvesting of rice effectively reduces P and additional macro and micro-nutrients from agrarian soil and runoff through plant uptake. In this study, soil, water, sugarcane, and rice plants at two different stages (flooded and vegetative) were analyzed for twelve different elements (Al, As, Co, Cr, Cu, Fe, Ni, Zn, Ca, Mn, Mg, and P) by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). 31P Nuclear Magnetic Resonance (NMR) spectra of the rice plants confirmed ten different P compounds being transported and/or transformed throughout the entirety of the sugarcane and rice plants. On average, dried rice plants contained 1677 ± 14 mg-P, of which 1277 ± 3.0 mg-P was in the panicle at the vegetative stage. Harvesting of the rice panicle has the potential to remove about 14.7 kg-P/ha for the top 10 cm of the soil. This present study demonstrates that in rotations with sugarcane crops and with no added P fertilizer, rice cultivation can reduce considerable amounts of P that would otherwise leach into the Greater Everglades from the Everglades Agricultural Area.

[Complications after Revision Total Knee Arthroplasties]. / Komplikace po revizních operacích totálních endoprotéz kolena.

PURPOSE OF THE STUDY The failure of arthroplasties and above all the issue of infection and its detection have become an ever more frequently discussed problem. The purpose of our study was to determine the frequency and the type of complications after revision total knee arthroplasties and to compare them with the frequency of complications after primary implantations. MATERIAL AND METHODS In our group of patients followed up in the period from January 2007 to December 2016, in 50 patients the revision surgery was performed for aseptic loosening and in 24 patients for deep infection. In the case of revision surgery for aseptic loosening, in 18 patients original sterilised components were used as a spacer, in 6 patients an articulating cement spacer was applied. Only the complications resulting in the performance of further revision were included in the statistics. A total of 13 patients underwent a primary implantation at another centre. The number of revisions and the reason for implant failure were monitored. The results were compared with the frequency of revision surgeries after primary total knee arthroplasty, of which 2,436 were carried out in the referred to period. RESULTS Of 2,436 primary endoprostheses, altogether 3.1 % failed. In 50 (2.1 %) patients aseptic loosening was reported, 24 patients (1 %) suffered from infection. The median time from primary implantation to revision was 11 years for aseptic loosening, 2 years for infection. The most frequent cause of failure was aseptic loosening. In the group of patients who underwent a revision surgery for aseptic loosening, another revision was necessary in 6 cases (12 %), in the group of patients after the two-stage revision surgery for infection, in 9 cases (37.5 %). The most frequent reason for revision surgery was infection - in both the groups this was the reason for 67 % of revision surgeries. DISCUSSION Our results obtained with respect to primary as well as revision surgeries for aseptic loosening correspond with the results reported by other authors. In the case of two-stage revision implantation, the reported frequency of recurrent infections is the same, the frequency of revision surgeries for aseptic causes is slightly lower in our group. The most frequent causes of revision surgery are also in agreement. In the case of primary implantation, the patients most frequently suffer from aseptic loosening, after revision surgeries another revision surgery is most often performed due to infection. The literature refers to studies suggesting the potential use of original components as a spacer with the same success rate as that achieved with the cement spacer. The original components produced good results in two thirds of two-stage revision implantations, which is why we can agree with these studies. CONCLUSIONS The results clearly show a noticeable increase in the frequency of complications in revision surgeries compared to primary surgeries. In comparison with primary implantations, a subsequent revision after the revision implantation for aseptic loosening was necessary three times more frequently, after the two-stage revision implantation for infection it was ten times more frequently. As the most problematic complication can be considered the infection in case of primary as well as revision interventions. It is obvious that aseptic loosening of the primary implant usually occurs later (the median of 11 years) than the development of deep infection (the median of 2 years). Key words: total knee arthroplasty, revision, failure, complications, aseptic loosening, infection, spacer.

Brevetoxin (PbTx-2) influences the redox status and NPQ of Karenia brevis by way of thioredoxin reductase.

The Florida red tide dinoflagellate, Karenia brevis, is the major harmful algal bloom dinoflagellate of the Gulf of Mexico and plays a destructive role in the region. Blooms of K. brevis can produce brevetoxins: ladder-shaped polyether (LSP) compounds, which can lead to adverse human health effects, such as reduced respiratory function through inhalation exposure, or neurotoxic shellfish poisoning through consumption of contaminated shellfish. The endogenous role of the brevetoxins remains uncertain. Recent work has shown that some forms of NADPH dependent thioredoxin reductase (NTR) are inhibited by brevetoxin-2 (PbTx-2). The study presented herein reveals that high toxin and low toxin K. brevis, which have a ten-fold difference in toxin content, also show a significant difference in their ability, not only to produce brevetoxin, but also in their cellular redox status and distribution of xanthophyll cycle pigments. These differences are likely due to the inhibition of NTR by brevetoxin. The work could shed light on the physiological role that brevetoxin fills for K. brevis.

Pigment alterations in the brown mussel Perna perna.

Potential sex and/or gametogenic stage differences in the metabolism of chlorophyll-a and carotenoids in the brown mussel Perna perna of southern Brazil were studied using high performance liquid chromatography (HPLC). Carotenoids derived directly from diet (phytoplankton) were fucoxanthin plus diatoxanthin (diatoms), alloxanthin (cryptophytes) and zeaxanthin (mainly cyanobacteria). Females accumulated carotenoid-diols and epoxides (~3-4 mg/g-dry wt.) while males had much lower concentrations (~0.7 mg/g-dry wt.). An antioxidant/free radical scavenging role is proposed for carotenoids in females. Mean ratios of chlorophyll plus derivatives (Chlns-a) to carotenoids for male and female P. perna were 50:1 and 4:1, respectively. The higher ratio in males relates to both higher carotenoid contents in females plus higher total Chlns-a in males (~22 mg/g-dry wt.), relative to the females (~4 mg/g-dry wt.). Chlorophyll-a metabolism in both sexes followed two distinct pathways. First, cyclization of pyropheophorbide-a gave 13(2), 17(3)-cyclopheophorbide-a-enol (CPPaE) which was further oxidized to hydroxy-chlorophyllone. Second, chlorophyll-a derivatives retaining the 13(2)-carbomethoxy moiety were oxidized to purpurin-18 which was hydrolyzed to chlorin-p(6). In both cases, metabolism of dietary chlorophyll-a was oxidative and derivatives could either serve as antioxidants or merely be the results of non-specific digestive processes.

[Reconstruction of a crushed chest with HI-TEX PARP NT implant]. / Die Rekonstruktion eines zertrümmerten Brustskeletts mithilfe des Implantats HI-TEX PARP NT.

The authors present the case of a 57-year-old man with polytrauma, who was injured in a train accident. Together with other injuries, he also sustained multiple comminuted fractures on the left half of the rib cage. These subsequently required surgical intervention because of thoracic instability and impending lung injury. Extensive damage to the thoracic skeleton was treated by removal of the damaged tissues and replacement by the HI-TEX PARP NT implant. The presented procedure is being discussed as an alternative to metallic fixation in thoracic instability in cases of devastating injury or injury resulting in bone and tissue loss.

The post-Paleozoic chronology and mechanism of 13C depletion in primary marine organic matter.

Carbon-isotopic compositions of geoporphyrins have been measured from marine sediments of Mesozoic and Cenozoic age in order to elucidate the timing and extent of depletion of 13C in marine primary producers. These results indicate that the difference in isotopic composition of coeval marine carbonates and marine primary photosynthate was approximately 5 to 7 permil greater during the Mesozoic and early Cenozoic than at present. In contrast to the isotopic record of marine primary producers, isotopic compositions of terrestrial organic materials have remained approximately constant for this same interval of time. This difference in the isotopic records of marine and terrestrial organic matter is considered in terms of the mechanisms controlling the isotopic fractionation associated with photosynthetic fixation of carbon. We show that the decreased isotopic fractionation between marine carbonates and organic matter from the Early to mid-Cenozoic may record variations in the abundance of atmospheric CO2.