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.     

PI3K-dependent lysosome exocytosis in nitric oxide-preconditioned hepatocytes

We investigated the signal mediators and the cellular events involved in the nitric oxide (NO)-induced hepatocyte resistance to oxygen deprivation in isolated hepatocytes treated with the NO donor (Z)-1-(N-methyl-N-[6-(N-methylammoniohexyl)amino])diazen-1-ium-1,2-diolate (NOC-9). NOC-9 greatly induced PI3K activation, as tested by phosphorylation of PKB/Akt. This effect was prevented by either 1H-(1,2,4)-oxadiazolo-(4,3)-quinoxalin-1-one, an inhibitor of the soluble guanylate cyclase (sGC), or KT5823, an inhibitor of cGMP-dependent kinase (cGK), as well as by farnesyl protein transferase inhibitor, which blocks the function of Ras GTPase. Bafilomycin A, an inhibitor of the lysosome-type vacuolar H+-ATPase, cytochalasin D, which disrupts the cytoskeleton-dependent organelle traffic, and wortmannin, which inhibits the PI3K-dependent traffic of lysosomes, all abolished the NOC-9-induced hepatocyte protection. The treatment with NOC-9 was associated with the PI3K-dependent peripheral translocation and fusion with the plasma membrane of lysosomes and the appearance at the cell surface of the vacuolar H+-ATPase. Inhibition of sGC, cGK, and Ras, as well as the inhibition of PI3K by wortmannin, prevented the exocytosis of lysosomes and concomitantly abolished the protective effect of NOC-9 on hypoxia-induced pHi and [Na+]i alterations and cell death. These data indicate that NO increases hepatocyte resistance to hypoxic injury by activating a pathway involving Ras, sGC, and cGK that determines PI3K-dependent exocytosis of lysosomes.     

Folding, activity and targeting of mutated human cathepsin D that cannot be processed into the double-chain form

The precursor of human cathepsin D (CD) is converted into the single-chain and the double-chain active polypeptides by subsequent proteolysis reactions taking place in the endosomal-lysosomal compartment and involving specific aminoacid sequences. We have mutagenized the region of aminoacids (comprising the beta-hairpin loop) involved in the latter proteolytic maturation step and generated a mutant CD that cannot be converted into the mature double-chain form. This mutant CD expressed in rodent cells reaches the lysosome and is stable as single-chain polypeptide, bears high-mannose type sugars, binds to pepstatin A and is enzymatically active, indicating that it is correctly folded. The present work provides new insights on the aminoacid region involved in the terminal processing of human CD and on the function of the processing beta-hairpin loop.     

On separation and identity of fern antheridiogens

Chromatographic studies show that the hormones controlling antheridiuminduction in the fern species Pteridium aquilinum (Polypodiaceae),Anemia phyllitidis and Lygodium japonicum (Schizaeaceae) aredifferent molecular entities. SCHRAUDOLF's report that gibberellic acid induces antheridiain A. phyllitidis and L. japonicum was confirmed. The activityspectrum of GAs towards species of different fern families stronglyresembles that of the native Anemia antheridiogen. However,the native antheridiogens of A. phyllitidis, and of Lygodiumjaponicum, are more species-selective in their action than isGA₃. Preliminary studies have yielded no conclusive evidenceon whether the native antheridiogens are gibberellins. (Received August 21, 1967; )     

Lumbar muscle electromyographic dynamic topography during flexion-extension

The objective of this study is to introduce dynamic topography of surface electromyography (SEMG) to visualize lumbar muscle myoelectric activity and provides a new view to analyze muscle activity in vivo. A total of 20 healthy male subjects and 15 males LBP were enrolled. An electrode-array was applied to the lumbar region to collect SEMG. The root mean square (RMS) value was calculated for each channel, and then a 160×120 matrix was constructed using a linear cubic spline interpolation of each scan to create a 2-D color topographic image. Along a definite interval of action, a series of RMS topography matrices was concatenated as a function of position and time, to form a dynamic topographical video of lumbar muscle activity. Relative area (RA), relative width (RW), relative height (RH) and Width-to-Height Ratio (W/H) were chosen as the four quantitative parameters in measuring topographic features. Normal RMS dynamic topography was found to have a consistent, symmetric pattern with a high intensity area in the paraspinal area. LBP patients had a different RMS dynamic topography, with an asymmetric, broad, or disorganized distribution. Quantitative SEMG features were found significantly different between normal control and LBP. After physiotherapy rehabilitation, the dynamic topography images of LBP tended towards the normal pattern.There are obvious differences in lumbar muscle coordination between healthy subjects and LBP patients. The dynamic topography allows the continuous visualization of the distribution of surface EMG signals and the coordination of muscular contractions.     

Chemotherapy drug response in ovarian cancer cells strictly depends on a cathepsin D-Bax activation loop

The ovarian cancer cell lines A2780 (wild-type p53) and NIHOVCAR3 (mutated p53) showed, respectively, sensitivity and resistance towards several chemotherapy drugs. We hypothesized that the two cell lines differ in their ability to activate the intrinsic death pathway and have, therefore, dissected the lysosome-mitochondrion signalling pathway by pharmacological inhibition or genetic manipulation of key regulators and executioners. Biochemical and morphological confocal fluorescence studies showed that: (1) In A2780 cells bcl-2 is expressed at an undetectable level, whereas Bax is expressed at a rather high level; by contrast, bcl-2 is highly expressed and Bax is expressed at extremely low levels in NIHOVCAR3 cells; (2) Chemotherapy treatment reduced the expression of bcl-2 in NIHOVCAR3 cells, yet these cells resisted to drug toxicity; (3) Cathepsin D (CD), not cathepsin B or L, mediates the activation of the mitochondrial intrinsic death pathway in A2780 cells; (4) Lysosome leakage and cytosolic relocation of CD occurs in the chemosensitive A2780 cells, not in the chemoresistant NIHOVCAR3 cells; (5) Bax is essential for the permeabilization of both lysosomes and mitochondria in A2780 cells exposed to chemotherapy drugs; (6) CD activity is mandatory for the oligomerization of Bax on both mitochondrial and lysosomal membranes; (7) Bax activation did not occur in the resistant NIHOVCAR3 cells despite their high content in CD. The present data are consistent with a model in which on treatment with a cytotoxic drug the activation of a CD-Bax loop leads to the generalized permeabilization of lysosomes and eventually of mitochondria, thus reaching the point of no return, and culminates with the activation of the caspase cascade. Our data also imply that dysfunctional permeabilization of lysosomes contributes to the development of chemoresistance.     

A microbiological assay for sterigmatocystin,T-2 toxin and zearalenone

A survey was done to find microorganisms useful for assaying sterigmatocystin; T-2 toxin and zearalenone.Staphylococcus aureus was found to be sensitive to T-2 toxin and zearalenone;Bacillus cereus was found to be sensitive to T-2 toxin only; andEscherichia coli was sensitive to sterigmatocystin. The response of the organisms to sterigmatocystin; T-2 toxin and zearalenone was found to be linear between 4 and 100 μg with sterigmatocystin toE. coli; between 2 and 25 μg with T-2 toxin toStaph, aureus andB. cereus; and between 4 and 100 μg with zearalenone toStaph, aureus. The lower limits of sensitivity of the test were 2 μg T-2 toxin and zearalenone, and 4 μg sterigmatocystin. The assay is rapid (15–17 hrs); simple and inexpensive; and can be used to verify the toxicity of samples and to confirm thin layer chromatographic results.     

The Deuterator: software for the determination of backbone amide deuterium levels from H/D exchange MS data

Background  

The combination of mass spectrometry and solution phase amide hydrogen/deuterium exchange (H/D exchange) experiments is an effective method for characterizing protein dynamics, and protein-protein or protein-ligand interactions. Despite methodological advancements and improvements in instrumentation and automation, data analysis and display remains a tedious process. The factors that contribute to this bottleneck are the large number of data points produced in a typical experiment, each requiring manual curation and validation, and then calculation of the level of backbone amide exchange. Tools have become available that address some of these issues, but lack sufficient integration, functionality, and accessibility required to address the needs of the H/D exchange community. To date there is no software for the analysis of H/D exchange data that comprehensively addresses these issues.     

Cathepsin D-Bax death pathway in oxidative stressed neuroblastoma cells

Hydrogen peroxide, the major oxidoradical species in the central nervous system, has been involved in neuronal cell death and associated neurodegenerative diseases. In this study, we have investigated the involvement of the lysosomal pathway in the cytotoxic mechanism of hydrogen peroxide in human neuroblastoma cells. Alteration of lysosomal and mitochondrial membrane integrity was shown to be an early event in the lethal cascade triggered by oxidative stress. Desferrioxamine (DFO), an iron chelator that abolishes the formation of reactive oxygen species within lysosomes, prevented lysosome leakage, mitochondrial permeabilization and caspase-dependent apoptosis in hydrogen peroxide-treated cells. Inhibition of cathepsin D, not of cathepsin B, as well as small-interference RNA-mediated silencing of the cathepsin D gene prevented hydrogen peroxide-induced injury of mitochondria, caspase activation, and TUNEL-positive cell death. Cathepsin D activity was shown indispensable for translocation of Bax onto mitochondrial membrane associated with oxidative stress. DFO abolished both the cytosolic relocation of Cathepsin D and the mitochondrial relocation of Bax in hydrogen peroxide-treated cells. siRNA-mediated down-regulation of Bax expression protected the cells from oxidoradical injury. The present study identifies the lysosome as the primary target and the axis cathepsin D-Bax as the effective pathway of hydrogen peroxide lethal activity in neuroblastoma cells.     

Benthic freshwater nematode community dynamics under conditions of Tilapia aquaculture in Egypt

Studies of the influence of fish aquaculture on benthic freshwater nematode assemblages are scarce, but could provide a way of gauging environmental effects. The abundance and diversity of nematode assemblages in response to Oreochromis niloticus aquaculture were investigated in Kafr El-Sheikh Governorate, Egypt, from July to November 2014 under conditions of irrigation (reference), fish farm pond with high Tilapia density, and fish farm pond effluent canal without fish. The nematode genera Adoncholaimus, Punctodora, Labronema, Oncholaimus and Odontolaimus were present at all sites. Environmental factors were not related to nematode distribution patterns. Tilapia predation and/or disturbance may explain reduced nematode abundance, especially of the largest genera, Adoncholaimus, Punctodora and Labronema at the fish farm site. The absence of fish from the drainage site allowed intergeneric nematode competitive exclusion, benefitting the largest nematodes and reducing diversity indices.