Characterization of halophilic Archaea isolated from different hypersaline ecosystems

Halobacterial representatives were isolated from salted fish, naturally occurring salt pans as well as artificial saline poolsin the Mediterranean area. The isolation techniques experimented proved successful, allowing halophilic archaea to be retrieved iralmost 72% of analysed samples. About 65% of strains could be presumptively ascribed to the speciellaloarcula marismortui by RFLP (Restriction Fragment Length Polymorphism) grouping and 16S rRNA gene sequence comparison. Nevertheless, cluster analysis of RAPD-PCR patterns revealed a wide heterogeneity among isolated strains. Biochemical features of technological interest, such as proteclic, lipolytic and decarboxylase activity, were investigated in order to elucidate the role of archaea during ripening of salted anchovies. Proteolytic activity was only evidenced on the sarcoplasmic fraction extracted from fresh anchovies and for only 4 strains out of 2 No strain revealed either lipolytic capability on cod liver oil or proteolytic activity on fresh anchovies myofibrillar extract. Finally, only one strain exhibited decarboxylase activity, minimizing the potential responsibility of cultivable archaea microflora in the spoilage of salted anchovies.     

Nuclear translocation of insulin receptor substrate-1 by oncogenes and Igf-I. Effect on ribosomal RNA synthesis

The insulin receptor substrate-1 (IRS-1) is one of the major substrates of both the insulin and IGF-I receptors and is generally localized in the cytosol/membrane fraction of the cell. We show here that a substantial fraction of IRS-1 is translocated to the nucleus in mouse embryo fibroblasts (MEF) expressing the simian virus 40 T antigen. Nuclear translocation of IRS-1 occurs also in MEF stimulated with IGF-I or in MEF expressing the oncogene v-src. Nuclear translocation of IRS-1 can be demonstrated by confocal microscopy, immunohistochemistry, or subcellular fractionation. An antibody to IRS-1 immunoprecipitates from nuclear fractions (but not from cytosolic fractions) the upstream binding factor, which is a key regulator of RNA polymerase I activity and ribosomal RNA (rRNA) synthesis. In agreement with this finding, in 32D murine hemopoietic cells, nuclear translocation of IRS-1 correlates with a markedly increased rRNA synthesis. Our experiments suggest that nuclear IRS-1 may play a specialized role in rRNA synthesis and/or processing.     

The Continuum of Physiological Impairment during Treadmill Walking in Patients with Mild-to-Moderate COPD: Patient Characterization Phase of a Randomized Clinical Trial

Background

To have a better understanding of the mechanisms of exercise limitation in mild-to-moderate chronic obstructive pulmonary disease (COPD), we compared detailed respiratory physiology in patients with COPD and healthy age- and sex-matched controls.

Methods

Data were collected during the pre-treatment, patient characterization phase of a multicenter, randomized, double-blind, crossover study. Patients with COPD met Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 or 2 spirometric criteria, were symptomatic, and had evidence of gas trapping during exercise. All participants completed pulmonary function and symptom-limited incremental treadmill exercise tests.

Results

Chronic activity-related dyspnea measured by Baseline Dyspnea Index was similarly increased in patients with GOLD 1 (n = 41) and 2 (n = 63) COPD compared with controls (n = 104). Plethysmographic lung volumes were increased and lung diffusing capacity was decreased in both GOLD groups. Peak oxygen uptake and work rate were reduced in both GOLD groups compared with controls (p<0.001). Submaximal ventilation, dyspnea, and leg discomfort ratings were higher for a given work rate in both GOLD groups compared with controls. Resting inspiratory capacity, peak ventilation, and tidal volume were reduced in patients with GOLD 2 COPD compared with patients with GOLD 1 COPD and controls (p<0.001).

Conclusions

Lower exercise tolerance in patients with GOLD 1 and 2 COPD compared with controls was explained by greater mechanical abnormalities, greater ventilatory requirements, and increased subjective discomfort. Lower resting inspiratory capacity in patients with GOLD 2 COPD was associated with greater mechanical constraints and lower peak ventilation compared with patients with GOLD 1 COPD and controls.

Trial Registration

ClinicalTrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT01072396","term_id":"NCT01072396"}}NCT01072396     

Testosterone-induced increase in muscle size in healthy young men is associated with muscle fiber hypertrophy

Administration of replacement doses of testosterone to healthy hypogonadal men and supraphysiological doses to eugonadal men increases muscle size. To determine whether testosterone-induced increase in muscle size is due to muscle fiber hypertrophy, 61 healthy men, 18-35 yr of age, received monthly injections of a long-acting gonadotropin-releasing hormone (GnRH) agonist to suppress endogenous testosterone secretion and weekly injections of 25, 50, 125, 300, or 600 mg testosterone enanthate (TE) for 20 wk. Thigh muscle volume was measured by magnetic resonance imaging (MRI) scan, and muscle biopsies were obtained from vastus lateralis muscle in 39 men before and after 20 wk of combined treatment with GnRH agonist and testosterone. Administration of GnRH agonist plus TE resulted in mean nadir testosterone concentrations of 234, 289, 695, 1,344, and 2,435 ng/dl at the 25-, 50-, 125-, 300-, and 600-mg doses, respectively. Graded doses of testosterone administration were associated with testosterone dose and concentration-dependent increase in muscle volume measured by MRI (changes in vastus lateralis volume, -4, +7, +15, +32, and +48 ml at 25-, 50-, 125-, 300-, and 600-mg doses, respectively). Changes in cross-sectional areas of both type I and II fibers were dependent on testosterone dose and significantly correlated with total (r = 0.35, and 0.44, P < 0.0001 for type I and II fibers, respectively) and free (r = 0.34 and 0.35, P < 0.005) testosterone concentrations during treatment. The men receiving 300 and 600 mg of TE weekly experienced significant increases from baseline in areas of type I (baseline vs. 20 wk, 3,176 +/- 186 vs. 4,201 +/- 252 microm(2), P < 0.05 at 300-mg dose, and 3,347 +/- 253 vs. 4,984 +/- 374 microm(2), P = 0.006 at 600-mg dose) muscle fibers; the men in the 600-mg group also had significant increments in cross-sectional area of type II (4,060 +/- 401 vs. 5,526 +/- 544 microm(2), P = 0.03) fibers. The relative proportions of type I and type II fibers did not change significantly after treatment in any group. The myonuclear number per fiber increased significantly in men receiving the 300- and 600-mg doses of TE and was significantly correlated with testosterone concentration and muscle fiber cross-sectional area. In conclusion, the increases in muscle volume in healthy eugonadal men treated with graded doses of testosterone are associated with concentration-dependent increases in cross-sectional areas of both type I and type II muscle fibers and myonuclear number. We conclude that the testosterone induced increase in muscle volume is due to muscle fiber hypertrophy.     

Mechanism of the exercise hyperkalemia: an alternate hypothesis

Wasserman, Karlman, William W. Stringer, Richard Casaburi,and Yong-Yu Zhang. Mechanism of the exercisehyperkalemia: an alternate hypothesis. J. Appl.Physiol. 83(2): 631-643, 1997.A progressivehyperkalemia is observed as exercise intensity increases. The currentmost popular hypothesis for the hyperkalemia is that theNa⁺-K⁺pump cannot keep pace with the K⁺efflux from muscle during the depolarization-repolarization process ofthe sarcolemmal membrane during muscle contraction. In this report, wepresent data that suggest an alternate hypothesis to those previouslydescribed. Because phosphocreatine (PCr) is a highly dissociated acidand creatine is neutral at cell pH, the concentration of nondiffusibleanions decreases, and an alkaline reaction takes place when PCrhydrolyzes. This creates a state of cation(K⁺) excess andH⁺ depletion in the cell. Toexamine the balance of K⁺ andH⁺ for exercising muscle duringthe early period of exercise when PCr changes most rapidly, catheterswere inserted into the brachial artery and femoral vein (FV) in fivehealthy subjects who performed two 6-min cycle ergometer exercise testsat 40 and 85% of peak oxygen uptake. FV blood was sampled every 5 sduring the first 2 min, then every 30 s for the remaining 4 min ofexercise and the first 3 min of recovery, and then less frequently forthe next 12 min. Arterial sampling was every 30 s during exercise andsimultaneous with FV sampling during recovery. ArterialK⁺ concentration([K⁺]) increase laggedFV [K⁺]increase. The hyperkalemia observed during early exerciseresults from K⁺ release fromskeletal muscle. FV[K⁺] increased by 5 sof the start of exercise and followed the rate ofH⁺ loss from the FV blood for thefirst 30 s of exercise. FV lactate andNa⁺ kinetics differed fromK⁺ kinetics during exercise andrecovery. As predicted from the PCr hydrolysis reaction, the exercisinglimb took up H⁺ and releasedK⁺ at the start of exercise (first30 s) at both exercise intensities, resulting in a FV metabolicalkalosis. K⁺ release wasessentially complete by 3 min, the time at which oxygen uptake (and,presumably, PCr) reached its asymptote. These findings lead us tohypothesize that the early K⁺release by the cell takes place withH⁺ exchange and that the majormechanism for the exercise hyperkalemia is the reduction innondiffusible intracellular anions in the myocyte as PCr hydrolyzes.

     

Development of polythene films for food packaging activated with an antilisterial bacteriocin from Lactobacillus curvatus 32Y

AIMS: The aims of this work were to (i) use a bacteriocin produced by Lactobacillus curvatus 32Y active against Listeria monocytogenes to activate polythene films by different methods, (ii) implement a large-scale process for antilisterial polythene films production and (iii) verify the efficacy of the developed films in inhibiting the growth of L. monocytogenes during the storage of meat products. METHODS AND RESULTS: The film was made active by using the antilisterial bacteriocin 32Y by Lact. curvatus with three different procedures: soaking, spraying and coating. The antimicrobial activity of the activated films was tested in plate assays against the indicator strain L. monocytogenes V7. All the used procedures yielded active polythene films although the quality of the inhibition was different. The coating was therefore employed to develop active polythene films in an industrial plant. The antimicrobial activity of the industrially produced films was tested in experiments of food packaging involving pork steak and ground beef contaminated by L. monocytogenes V7 at roughly 10(3) CFU cm(-2) and gram respectively. The results of the challenge tests showed the highest antimicrobial activity after 24 h at 4 degrees C, with a decrease of about 1 log of the L. monocytogenes population. CONCLUSIONS: Antimicrobial packaging can play an important role in reducing the risk of pathogen development, as well as extending the shelf life of foods. SIGNIFICANCE AND IMPACT OF THE STUDY: Studies of new food-grade bacteriocins as preservatives and development of suitable systems of bacteriocin treatment of plastic films for food packaging are important issues in applied microbiology and biotechnology, both for implementing and improving effective hurdle technologies for a better preservation of food products.     

Cluster Analysis in Patients with GOLD 1 Chronic Obstructive Pulmonary Disease

Background

We hypothesized that heterogeneity exists within the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1 spirometric category and that different subgroups could be identified within this GOLD category.

Methods

Pre-randomization study participants from two clinical trials were symptomatic/asymptomatic GOLD 1 chronic obstructive pulmonary disease (COPD) patients and healthy controls. A hierarchical cluster analysis used pre-randomization demographics, symptom scores, lung function, peak exercise response and daily physical activity levels to derive population subgroups.

Results

Considerable heterogeneity existed for clinical variables among patients with GOLD 1 COPD. All parameters, except forced expiratory volume in 1 second (FEV₁)/forced vital capacity (FVC), had considerable overlap between GOLD 1 COPD and controls. Three-clusters were identified: cluster I (18 [15%] COPD patients; 105 [85%] controls); cluster II (45 [80%] COPD patients; 11 [20%] controls); and cluster III (22 [92%] COPD patients; 2 [8%] controls). Apart from reduced diffusion capacity and lower baseline dyspnea index versus controls, cluster I COPD patients had otherwise preserved lung volumes, exercise capacity and physical activity levels. Cluster II COPD patients had a higher smoking history and greater hyperinflation versus cluster I COPD patients. Cluster III COPD patients had reduced physical activity versus controls and clusters I and II COPD patients, and lower FEV₁/FVC versus clusters I and II COPD patients.

Conclusions

The results emphasize heterogeneity within GOLD 1 COPD, supporting an individualized therapeutic approach to patients.

Trial registration

www.clinicaltrials.gov. NCT01360788 and NCT01072396.