Myxomycetes in soil

The myxomycetes are a group of protists that form a monophyletic taxon in the phylum Amoebozoa. Evidence of their evolutionary success is the fact that they account for more species (ca. 900 are currently recognized) than the combined total for the rest of the Amoebozoa. Moreover, myxomycetes are present in every terrestrial environment investigated to date and also, as amoebae or flagellated cells, in aquatic environments where they cannot form fruiting bodies. Even if culture-based methods tend to underestimate their occurrence in soil, myxomycetes probably account for ∼50% of soil amoebae. The emergence of molecular-based methods has revolutionized our concepts of biodiversity, but myxomycetes are conspicuously absent from all environmental surveys. Herein we show that this is due to their highly diverging SSU rRNA gene sequences, which contain numerous Group I introns.Further proof comes from a recent study that used a massive sequencing approach without primer bias to amplify RNAs. The results obtained show that the mycetozoans (myxomycetes along with dictyostelids and protostelids) are indeed a dominant group of soil protozoans.     

Intracellular acidosis enhances the excitability of working muscle

Intracellular acidification of skeletal muscles is commonly thought to contribute to muscle fatigue. However, intracellular acidosis also acts to preserve muscle excitability when muscles become depolarized, which occurs with working muscles. Here, we show that this process may be mediated by decreased chloride permeability, which enables action potentials to still be propagated along the internal network of tubules in a muscle fiber (the T system) despite muscle depolarization. These results implicate chloride ion channels in muscle function and emphasize that intracellular acidosis of muscle has protective effects during muscle fatigue.     

L-dihydroxyphenylalanine: effect on S-adenosylmethionine in brain

Forty-five minutes after intraperitoneal injection of a single dose (100 milligrams per kilogram) of L-dihydroxyphenylalanine, the concentration of S-adenosylmethionine in rat brain was lowered by 76 percent. As little as 10 milligrams of L-dihydroxyphenylalanine per kilogram decreased content of S-adenosylmethionine in the adrenal medulla by 51 percent, whereas 100 milligrams per kilogram did not significantly depress concentration of S-adenosylmethionine in the liver in this time interval. Concentration of S-adenosylmethionine in the brain varied diurnally; L-dihydroxyphenylalanine lowered this concentration whether administered at the daily peak or at the nadir.     

Radioisotope dating with an accelerator: a blind measurement

The age of a sample of carbon dioxide has been determined by accelerating the carbon with a cyclotron and detecting the carbon-14 ions in the beam. Nitrogen-14 was eliminated as a background through the use of a range-separation technique. To avoid all possibility of experimenter bias, the measurement was conducted in a blind fashion.     

Grazing Method Effect on Topographical Vegetation Characteristics and Livestock Performance in the Nebraska Sandhills

A study was conducted on upland range in the Nebraska Sandhills to determine differences in plant species frequency of occurrence and standing crop at various topographic positions on pastures grazed with short-duration grazing (SDG) and deferred-rotation grazing (DRG). Pastures within each grazing treatment were grazed at comparable stocking rates (SDG = 1.84 animal unit months (AUM) · ha^?1; DRG = 1.94 AUM · ha^?1) by cow–calf pairs from 1999 to 2005 and cow–calf pairs and spayed heifers from 2006 to 2008. Plant frequency of occurrence data were collected from permanently marked transects prior to, midway through, and at the conclusion of the study (1998, 2003, and 2008, respectively) and standing crop data were collected annually from 2001 to 2008 at four topographic positions (dune top, interdune, north slope, and south slope). Livestock performance data were collected during the last 3 yr of the study (2006 to 2008). Positive change in frequency of occurrence of prairie sandreed (Calamovilfa longifolia [Hook.] Scribn.) was 42% greater on DRG pastures than SDG after 10 yr. Total live standing crop did not differ between DRG and SDG except in 2001 when standing crop was 23% greater on DRG pastures. Standing crop of forbs and sedge was variable between grazing methods on interdune topographic positions depending on year. Average daily gain of spayed heifers (0.84 ±  kg · d^?1 SE) did not differ between SDG and DRG. Overall, SDG was not superior to a less intensively managed grazing method (i.e., DRG) in terms of vegetation characteristics and livestock performance.     

Retrospective evaluation of the use of amiodarone in dogs with arrhythmias (from 2003 to 2010)

Objectives : To evaluate the efficacy of amiodarone in dogs with refractory supraventricular and ventricular arrhythmias and to document the side effects in treated dogs. Methods : Records of 28 dogs were retrospectively searched to document indication for amiodarone administration, heart rate, alkaline phosphatase, alanine aminotransferase, thyroxine (T4) and thyroid stimulating hormone values before and after starting treatment and during follow‐up periods. Results : Sixteen dogs with supraventricular and 12 dogs with ventricular arrhythmias were treated with amiodarone. Amiodarone treatment significantly reduced the heart rate (P<0.001) and resulted in improvement in the severity of the arrhythmia and clinical signs in 26 dogs. There were no significant differences in alkaline phosphatase (P=0.596), alanine aminotransferase (P=0.842), T4 (P=0.789) and thyroid stimulating hormone (P=0.064) before and after starting amiodarone. On maintenance therapy, median amiodarone blood levels were within the accepted reference range (0.5 to 2.0 mg/L) at 0.8 mg/L (range 0.2 to 11.6 mg/L), but the majority of the desethylamiodarone levels were below normal at 0.1 mg/L (range 0.1 to 0.9 mg/L), based on human reference intervals (0.5 to 2.0 mg/L). Clinical Significance : Amiodarone may be an effective and safe alternative to treat supraventricular and ventricular arrhythmias in dogs, when common anti‐arrhythmic drugs are not effective or contraindicated.