Similar hypotensive responses to resistance exercise with and without blood flow restriction

Low intensity resistance exercise (RE) with blood flow restriction (BFR) has gained attention in the literature due to the beneficial effects on functional and morphological variables, similar to those observed during traditional RE without BFR, while the effects of BFR on post-exercise hypotension remain unclear. The aim of the present study was to compare the blood pressure (BP) response of trained normotensive individuals to RE with and without BFR. In this cross-over randomized trial, eight male subjects (23.8 ± 4 years, 74 ± 3 kg, 174 ± 4 cm) completed two exercise protocols: traditional RE (3 x 10 repetitions at 70% one-repetition maximum [1-RM]) and low intensity RE (3 x 15 repetitions at 20% 1-RM) with BFR. Blood pressure measurements were performed after 15 min of seated rest (0), immediately after and 10 min, 20 min, 30 min, 40 min, 50 min and 60 min after the experimental sessions. Similar hypotensive effects for systolic BP (SBP) were observed for both protocols (P < 0.05) after exercise, with no differences between groups (P > 0.05) and no statistically significant difference for diastolic BP (P > 0.05). These results suggest that in normotensive trained individuals, both traditional RE and RE with BFR induce hypotension for SBP, which is important to prevent cardiovascular disturbances.     

Mycobacterial ecology of the Rio Grande

This is the first study to characterize the environmental conditions which contribute to the presence and proliferation of environmental mycobacteria in a major freshwater river. Over 20 different species of environmental mycobacteria were isolated, including the pathogenic M. avium and M. kansasii. Species of the rapidly growing M. fortuitum complex were the most commonly isolated mycobacteria, and one-third of all isolates were not identified at the species level, even by 16S sequencing. PCR restriction analysis of the hsp65 gene was more accurate and rapid than biochemical tests and as accurate as yet less expensive than 16S sequencing, showing great promise as a new tool for species identification of environmentally isolated mycobacteria. Total environmental mycobacteria counts positively correlated with coliform and Escherichia coli counts and negatively correlated with chemical toxicity and water temperature. Environmental mycobacteria can survive in the alkaline conditions of the river despite previous reports that especially acidic conditions favor their presence. A representative river isolate (M. fortuitum) survived better than E. coli O157:H7 at pHs below 7 and above 8 in nutrient broth. The river strain also retained viability at 8 ppm of free chlorine, while E. coli was eliminated at 2 ppm and above. Thus, in vitro studies support environmental observations that a variety of extreme conditions favor the hardy environmental mycobacteria.     

Characterization and kinetics of isoenzymes of pyruvate kinase from developing castor bean endosperm

Isozymes of pyruvate kinase (PK) have been isolated from developing castor bean endosperm. One isozyme, PK_c, is localized in the cytosol, and the other, PK_p, is in the plastid. Both isozymes need monovalent and divalent cations for activity, requirements which can be filled by K⁺ and Mg²⁺. Both isozymes are inhibited by citrate, pyruvate, and ATP. PK_c has a much broader pH profile than PK_p and is also more stable. Both have the same K_m (0.05 millimolar) for PEP, but PK_p has a 10-fold higher K_m (0.3 millimolar) for ADP than PK_c (0.03 millimolar). PK_c also has a higher affinity for alternate nucleotide substrates than PK_p. The two isozymes have different kinetic mechanisms. Both have an ordered sequential mechanism and bind phosphoenolpyruvate before ADP. However, the plastid isozyme releases ATP first, whereas pyruvate is the first product released from the cytosolic enzyme. The properties of the two isozymes are similar to those of their counterparts in green tissue.     

Lactate dehydrogenase (LDH) gene duplication during chordate evolution: the cDNA sequence of the LDH of the tunicate Styela plicata

L-Lactate dehydrogenase (L-LDH, E.C. 1.1.1.27) is encoded by two or three loci in all vertebrates examined, with the exception of lampreys, which have a single LDH locus. Biochemical characterizations of LDH proteins have suggested that a gene duplication early in vertebrate evolution gave rise to Ldh-A and Ldh-B and that an additional locus, Ldh-C arose in a number of lineages more recently. Although some phylogenetic studies of LDH protein sequences have supported this pattern of gene duplication, others have contradicted it. In particular, a number of studies have suggested that Ldh-C represents the earliest divergence among vertebrate LDHs and that it may have diverged from the other loci well before the origin of vertebrates. Such hypotheses make explicit statements about the relationship of vertebrate and invertebrate LDHs, but to date, no closely related invertebrate LDH sequences have been available for comparison. We have attempted to provide further data on the timing of gene duplications leading to multiple vertebrate LDHs by determining the cDNA sequence of the LDH of the tunicate Styela plicata. Phylogenetic analyses of this and other LDH sequences provide strong support for the duplications giving rise to multiple vertebrate LDHs having occurred after vertebrates diverged from tunicates. The timing of these LDH duplications is consistent with data from a number of other gene families suggesting widespread gene duplication near the origin of vertebrates. With respect to the relationships among vertebrate LDHs, our data are not consistent with previous claims that Ldh-C represented the earliest divergence. However, the precise relationships among some of the main lineages of vertebrate LDHs were not resolved in our analyses.      

Modelling the Health Impact of an English Sugary Drinks Duty at National and Local Levels

Background

Increasing evidence associates excess refined sugar intakes with obesity, Type 2 diabetes and heart disease. Worryingly, the estimated volume of sugary drinks purchased in the UK has more than doubled between 1975 and 2007, from 510ml to 1140ml per person per week. We aimed to estimate the potential impact of a duty on sugar sweetened beverages (SSBs) at a local level in England, hypothesising that a duty could reduce obesity and related diseases.

Methods and Findings

We modelled the potential impact of a 20% sugary drinks duty on local authorities in England between 2010 and 2030. We synthesised data obtained from the British National Diet and Nutrition Survey (NDNS), drinks manufacturers, Office for National Statistics, and from previous studies. This produced a modelled population of 41 million adults in 326 lower tier local authorities in England. This analysis suggests that a 20% SSB duty could result in approximately 2,400 fewer diabetes cases, 1,700 fewer stroke and coronary heart disease cases, 400 fewer cancer cases, and gain some 41,000 Quality Adjusted Life Years (QALYs) per year across England. The duty might have the biggest impact in urban areas with young populations.

Conclusions

This study adds to the growing body of evidence suggesting health benefits for a duty on sugary drinks. It might also usefully provide results at an area level to inform local price interventions in England.     

Plastid development in primary leaves of Phaseolus vulgaris

Summary The development of increased activities of ribulosediphosphate carboxylase (EC 4.1.1.39) and of phosphoribulokinase (EC 2.7.1.19) in greening bean leaves was completely inhibited by D-threo chloramphenicol but unaffected by L-threo chloramphenicol. This indicates that these enzymes are synthesized by the ribosomes of the developing plastids. A different mechanism appears to be responsible for the development of activity of NADP-dependent triosephosphate dehydrogenase (EC 1.2.1.13) where the D-threo isomer gave 45% inhibition and the L-threo isomer gave 18% inhibition. Thus both specific (D-threo isomer) and unspecific (both isomers) inhibition occurred. It is suggested that the development of NADP-dependent triosephosphate dehydrogenase activity may result from the allosteric activation, in the plastids, of the NAD-dependent enzyme (Müller et al., 1969) which has been synthesized by cytoplasmic ribosomes. Neither isomer inhibited the development of five other enzymes of the photosynthetic carbon cycle namely ribosephosphate isomerase (EC 5.3.1.6), phosphoglycerate kinase (EC 2.7.2.3), triosephosphate isomerase (EC 5.3.1.1), tructosediphosphate aldolase (EC 4.1.2.13) and transketolase (EC 2.2.1.1), but there was a significant stimulation of the activity of transketolase by D-threo chloramphenicol.     

Analysis of molecular inversion probe performance for allele copy number determination

We have developed a new protocol for using molecular inversion probes to accurately and specifically measure allele copy number. The new protocol provides for significant improvements, including the reduction of input DNA (from 2 μg) by more than 25-fold (to 75 ng total genomic DNA), higher overall precision resulting in one order of magnitude lower false positive rate, and greater dynamic range with accurate absolute copy number up to 60 copies.     

Caspase-mediated cleavage of the exosome subunit PM/Scl-75 during apoptosis

Recent studies have implicated the dying cell as a potential reservoir of modified autoantigens that might initiate and drive systemic autoimmunity in susceptible hosts. A number of subunits of the exosome, a complex of 3'→5' exoribonucleases that functions in a variety of cellular processes, are recognized by the so-called anti-PM/Scl autoantibodies, found predominantly in patients suffering from an overlap syndrome of myositis and scleroderma. Here we show that one of these subunits, PM/Scl-75, is cleaved during apoptosis. PM/Scl-75 cleavage is inhibited by several different caspase inhibitors. The analysis of PM/Scl-75 cleavage by recombinant caspase proteins shows that PM/Scl-75 is efficiently cleaved by caspase-1, to a smaller extent by caspase-8, and relatively inefficiently by caspase-3 and caspase-7. Cleavage of the PM/Scl-75 protein occurs in the C-terminal part of the protein at Asp369 (IILD³⁶⁹↓G), and at least a fraction of the resulting N-terminal fragments of PM/Scl-75 remains associated with the exosome. Finally, the implications of PM/Scl-75 cleavage for exosome function and the generation of anti-PM/Scl-75 autoantibodies are discussed.