Adenine nucleotide levels and adenylate energy charge in Zostera marina (eelgrass): determination and application

An analytical technique was developed to measure adenine nucleotide levels (ATP, ADP, AMP) and adenylate energy charge (EC) in Zostera marina (eelgrass), a submerged marine angiosperm. A tissue comparison and seasonal survey provide baseline information on natural adenylate variability. The methodology developed can be suitably adapted to other macrophyte species as well. Plants were frozen, lyophilized, scraped free of epiphytes, and homogenized. Adenylates were extracted with boiling 1 mM EDTA + 5% (w/v) PVPP (pH 7.6), and assayed by enzymic conversion of AMP and ADP to ATP, followed by quantitative analysis of ATP via the firefly bioluminescent reaction. ATP, ADP, total adenylates (AT), and EC were highest in leaf tissue (photophosphorylating source), while all adenylates were lowest in root plus rhizome. Monthly time series with aboveground tissue show ATP concentration highest in August and lowest in April, corresponding to periods of senescence (decreased ATP utilization) and growth (increased ATP utilization), respectively. Response of adenine nucleotides and EC in Z. marina to nutrient enrichment, light reduction, and herbicide (atrazine) exposure was evaluated as a monitor of metabolic state. Nutrient enrichment over 2 weeks increased epiphyte colonization, which in turn, appeared to negatively impact Z. marina adenylate content, net productivity, and growth. Z. marina ATP, AT, and EC were weakly and positively correlated with nutrients and light, but decreased over time. Short-term (6 hr) atrazine stress reduced ATP and AT at both 10 and 100 ppb, but EC remained constant. Net productivity decreased at 100, but not at 10 ppb atrazine over 6 hrs. Long-term (21 day) atrazine stress was evident from growth inhibition and 50% mortality near 100 ppb. EC was reduced at 0.1, 1.0, and 10 ppb atrazine, but ATP and EC increased with physiological adaptation to severe stress (100 ppb) after 21 days. Apparently, ATP and AT decrease over the short-term but rebound over the long-term with severe atrazine stress, increasing beyond control levels before plant death results. Supplementing adenine nucleotide and EC results with more conventional quantitative analyses would afford greater knowledge of physiological response to environmental variation

Laboratory-based ergometry for swimmers: a narrative review

INTRODUCTION: First widely available dry-land training machines for swimmers were introduced about 40 years ago. They were designed so that swimmers could perform resistance exercise whilst more-closely replicating the movements of swimming, than when using other gymnasium-based resistance training machines. This narrative review categorises and summarises what has been shown by the studies that have utilised laboratory-based ergometry for swimmers. EVIDENCE ACQUISITION: A systematic search was conducted in PubMed, Web of Science, ScienceDirect and Scopus (1970-2018) and relevant publications were included. Publications were grouped into 4 main areas of research: (i) physiological responses to exercise, (ii) functional evaluation of swimmers, (iii) monitoring of training, and (iv) muscular work output of swimmers. EVIDENCE SYNTHESIS: Significant differences were showed between swim bench exercise and real swimming, especially in regard to the muscles involved. The difficulties of accurate reproduction of the movements and coordinated dynamic actions of swimming have not been overcome. Nevertheless, the literature shows that the use of these devices has provided a valuablecontribution to swimming physiology, while overcoming difficulties presented by attempting to make physiological measurements in the water. CONCLUSIONS: In spite of its limitations, laboratory-based ergometry has allowed a valuable contribution to the understanding of the physiology, effects of training and efficiency of swimming

Комбинированная антигипертензивная терапия у больных артериальной гипертензией, перенесших острую респираторную вирусную инфекцию

ГИПЕРТЕНЗИЯ /ЛЕК ТЕРКРОВЕНОСНЫХ СОСУДОВ БОЛЕЗНИКОМБИНИРОВАННОЕ ЛЕЧЕБНОЕ ВОЗДЕЙСТВИЕАНТИГИПЕРТЕНЗИВНЫЕ СРЕДСТВА /ТЕР ПРИМРЕСПИРАТОРНЫЕ ИНФЕКЦИИ /ОСЛВИРУСНЫЕ БОЛЕЗНИ /ОС

Polychlorinated Biphenyl Congener Patterns in Fish near the Hanford Site (Washington State, USA)

It is well-known that absorption, distribution, metabolism, and excretion (ADME) processes in fish can alter polychlorinated biphenyl (PCB) congener patterns in fish, but these patterns have never been investigated using an advanced source-apportionment tool. In this work, PCB congener patterns in freshwater fish were examined with positive matrix factorization (PMF). PCB congeners were quantified via EPA Method 1668 in fillet and carcass of six species in four study areas in the Columbia River near the Hanford Site. Six factors were resolved with PMF2 software. Depletion and enhancement of PCB congeners in factors, relative to Aroclor 1254, suggested biotransformation (via cytochrome P450) and bioaccumulation in fish, respectively. Notable differences were observed among species and across study locations. For example, sturgeon and whitefish exhibited congener patterns consistent with Aroclor weathering, suggesting potential PCB metabolism in these species. In terms of location, average concentration of total PCBs for all species combined was significantly higher (<i>P</i> < 0.05) at Hanford 100 and 300 areas, relative to upriver and downriver study sites. Furthermore, a distinct PCB signature in sturgeon and whitefish, collected at Hanford study areas, suggests that Hanford is a unique PCB source