Print versus website physical activity programs: A randomized trial

Mediated physical activity interventions can reach large numbers of people at low cost. Programs delivered through the mail that target the stage of motivational readiness have been shown to increase activity. Communication technology (websites and e-mail) might provide a means for delivering similar programs. Randomized trial conducted between August and October 2001. Participants included staff at an Australian university (n=655; mean AGE=43, standard deviation, 10 years). Participants were randomized to either an 8-week, stage-targeted print program (Print) or 8-week, stage-targeted website (Web) program. The main outcome was change in self-reported physical activity.

Chronic ethanol treatment leads to increased ornithine decarboxylase activity: Implications for a role of polyamines in ethanol dependence and withdrawal

Recent research has focused on the N-methyl-D-aspartate receptor system as a major site of ethanol action in the brain and specifically on compensatory changes in the expression of the polyamine-sensitive NR2B subunit. Therefore, we examined the effects of chronic ethanol treatment on polyamine homeostasis in the rat brain. Wistar rats were made dependent by ethanol vapor inhalation. This caused a rise in hippocampal ornithine decarboxylase (ODC) activity that was correlated with the appearance of physiological dependence. ODC activity returned to control levels within 3 days of ethanol withdrawal. Enzyme activity also increased in the cerebral cortex, striatum, and cerebellum of the ethanol-dependent rats. The concentration of the polyamines (putrescine, spermidine, and spermine) in the hippocampus was increased in ethanol-dependent rats. Injection of the ODC inhibitor, gamma-difluoromethylornithine (500 mg/kg) at the onset of withdrawal resulted in a significant reduction in the severity of withdrawal behaviors. The level of ODC activity and the severity of withdrawal behaviors were positively correlated. Perturbed polyamine homeostasis may represent an important molecular component in the initiation of ethanol withdrawal behaviors in the ethanol-dependent rat.

Role of the 6-20 disulfide bridge in the structure and activity of epidermal growth factor

Two synthetic analogues of murine epidermal. growth factor, [Abu6, 20] mEGF4-48 (where Abu denotes amino-butyric acid) and [G1, M3, K21, H40] mEGF1-48, have been investigated by NMR spectroscopy. [Abu6, 20] mEGF4-48 was designed to determine the contribution of the 6-20 disulfide bridge to the structure and function of mEGF The overall structure of this analogue was similar to that of native mEGF, indicating that the loss of the 6-20 disulfide bridge did not affect the global fold of the molecule. Significant structural differences were observed near the N-terminus, however, with the direction of the polypeptide chain between residues four and nine being altered such that these residues were now located on the opposite face of the main beta-sheet from their position in native mEGF Thermal denaturation experiments also showed that the structure of [Abu6, 20] mEGF4-48 was less stable than that of mEGF. Removal of this disulfide bridge resulted in a significant loss of both mitogenic activity in Balb/c 3T3 cells and receptor binding on A431 cells compared with native mEGF and mEGF4-48, implying that the structural changes in [Abu6, 20] mEGF4-48, although limited to the N-terminus, were sufficient to interfere with receptor binding. The loss of binding affinity probably arose mainly from steric interactions of the dislocated N-terminal region with part of the receptor binding surface of EGF [G1, M3, K21, H40] mEGF1-48 was also synthesized in order to compare the synthetic polypeptide with the corresponding product of recombinant expression. Its mitogenic activity in Balb/c 3T3 cells was similar to that of native mEGF and analysis of its H-1 chemical shifts suggested that its structure was also very similar to native.

Crystal and molecular structure of 2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone (NIH) and its iron(III) complex: an iron chelator with anti-tumour activity

Previous studies have demonstrated that 2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone (NIH) and several other aroylhydrazone chelators possess anti-neoplastic activity due to their ability to bind intracellular iron. In this study we have examined the structure and properties of NIH and its Fe-III complex in order to obtain further insight into its anti-tumour activity. Two tridentate NIH ligands deprotonate upon coordination to Fe-III in a meridional fashion to form a distorted octahedral, high-spin complex. Solution electrochemistry of [Fe(NIH-H)(2)](+) shows that the trivalent oxidation state is dominant over a wide potential range and that the Fe-II analogue is not a stable form of this complex. The fact that [Fe(NIH-H)(2)](+) cannot-cycle between the Fe-II and Fe-III states suggests that the production of toxic free- radical species, e.g. OH. or O2(.-),is not part of this ligand's cytotoxic action. This suggestion is supported by cell culture experiments demonstrating that the addition of Fe-III to NIH prevents its anti-proliferative effect. The chemistry of this chelator and its Fe-III complex are discussed in the context of understanding its anti-tumour activity.

A six-year longitudinal study of the relationship of physical activity to bone mineral accrual in growing children: The University of Saskatchewan bone mineral accrual study

To investigate the influence of physical activity on bone mineral accrual during the adolescent years, we analyzed 6 years of data from 53 girls and 60 boys. Physical activity, dietary intakes, and anthropometry were measured every 6 months and dual-energy X-ray absorptiometry scans of the total body (TB), lumbar spine (LS), and proximal femur (Hologic 2000, array mode) were collected annually. Distance and velocity curves for height and bone mineral content (BMC) were fitted for each child at several skeletal sites using a cubic spline procedure, from which ages at peak height velocity (PHV) and peak BMC velocity (PBMCV) were identified. A mean age- and gender-specific standardized activity (Z) score was calculated for each subject based on multiple yearly activity assessments collected up until age of PHV. This score was used to identify active (top quartile), average (middle 2 quartiles), or inactive (bottom quartile) groups. Two-way analysis of covariance, with height and weight at PHV controlled for, demonstrated significant physical activity and gender main effects (but no interaction) for PBMCV, for BMC accrued for 2 years around peak velocity, and for BMC at 1 year post-PBMCV for the TB and femoral neck and for physical activity but not gender at the LS (all p < 0.05). Controlling for maturational and size differences between groups, we noted a 9% and 17% greater TB BMC for active boys and girls, respectively, over their inactive peers 1 year after the age of PBMCV. We also estimated that, on average, 26% of adult TB bone mineral was accrued during the 2 years around PBMCV.

Chemical synthesis, antibacterial activity and conformation of diptericin, an 82-mer peptide originally isolated from insects

The small amounts of antibacterial peptides that can be isolated from insects do not allow detailed studies of their range of activity, side-chain sugar requirements, or their conformation, factors that frequently play roles in the mode of action. In this paper, we report the solid-phase step-by-step synthesis of diptericin, an 82-mer peptide, originally isolated from Phormia terranovae. The unglycosylated peptide was purified to homogeneity by conventional reversed-phase high performance liquid chromatography, and its activity spectrum was compared to that Of synthetic unglycosylated drosocin, which shares strong sequence homology with diptericin's N-terminal domain. Diptericin appeared to have antibacterial activity:for only a limited number of Gram-negative bacteria. Diptericin's submicromolar potency against Escherichia coli strains indicated that, in a manner similar to drosocin, the presence of the carbohydrate side chain is not,necessary to kill bacteria. Neither the N-terminal, drosocin-analog fragment, nor the C-terminal, glycine-rich attacin-analog region was active against any of the bacterial strains studied, regardless of whether the Gal-GalNAc disaccharide units were attached. This suggested that the active site of diptericin fell outside the drosocin or attacin homology domains. In addition, the conformation of diptericin did not seem to play a role in the antibacterial activity, as was demonstrated by the complete lack of ordered structure by two-dimensional nuclear magnetic resonance spectroscopy and circular dichroism. Diptericin completely killed bacteria within I h, considerably faster than drosocin and the attacins; unlike some other, fast-acting antibacterial peptides, diptericin did not lyse normal mammalian cells. Taken together, these data suggest diptericin does not belong to any known class of antibacterial peptides.

Chemical synthesis, characterization and activity of RK-1, a novel alpha-defensin-related peptide

The 32-residue peptide, RK-1, a novel kidney-derived three disulfide-bonded member of the antimicrobial alpha-defensin family, was synthesized by the continuous now Fmoc-solid phase method. The crude, cleaved and S-reduced Linear peptide was both efficiently folded and oxidized in an acidic solution of aqueous dimethyl sulfoxide. Following purification of the resulting product, it was shown by a variety of analytical techniques, including matrix assisted laser desorption time of flight mass spectrometry, to possess a very high degree of purity. The disulfide bond pairing of the synthetic peptide was determined by H-1-NMR spectroscopy and confirmed to be a Cys(1)-Cys(6), Cys(2)-Cys(4), Cys(3)-Cys(5) arrangement similar to other mammalian alpha-defensin peptides. The synthetic RK-1 was also shown to inhibit the growth of Escherichia coli type strain NCTC 10418, Copyright (C) 2000 European Peptide Society and John Wiley & Sons, Ltd.

Sequential increase in Egr-1 and AP-1 DNA binding activity in the dentate gyrus following the induction of long-term potentiation

Establishment of long-term potentiation (LTP) at perforant path synapses is highly correlated with increased expression of Egr and AP-1 transcription factors in rat dentate gyrus granule cells. We have investigated whether increased transcription factor levels are reflected in increased transcription factor activity by assessing Egr and AP-I DNA binding activity using gel shift assays. LTP produced an increase in binding to the Egr element, which was NMDA receptor-dependent and correlated closely with our previously reported increase in Egr-1 (zif/268) protein levels. Supershift analysis confirmed involvement of Egr-1, but not Egr-2 in the DNA binding activity. AP-1 DNA binding was also rapidly elevated in parallel with protein levels, however, the peak increase in activity was delayed until 4 h, a time point when we have previously shown that only jun-D protein was elevated. These data indicate that binding of Egr-1 and AP-1 to their response elements is increased in two phases. This may result in activation of distinct banks of target genes which contribute to the establishment of persistent LTP. (C) 2000 Elsevier Science B.V. All rights reserved.

Larval activity levels and delayed metamorphosis affect post-larval performance in the colonial, ascidian Diplosoma listerianum

It is becoming widely recognized that extending the larval period of marine invertebrates, especially of species with non-feeding larvae, can affect post-larval performance. As these carry-over effects are presumed to be caused by the depletion of larval energy reserves, we predicted that the level of larval activity would also affect post-larval performance. This prediction was tested with the cosmopolitan colonial ascidian Diplosoma listerianum in field experiments in southern Australia. Diplosoma larvae, brooded in the parent colony, are competent to settle immediately after spawning, and they remain competent to metamorphose for > 15 h. Some larvae were induced to metamorphose 0 to 6 h after release, whilst others were induced to swim actively by alternating light and dark periods for up to 3 h prior to metamorphosis. Juvenile colonies were then transplanted to a subtidal field site in Port Phillip Bay and left to grow for up to 3 wk. Extending the larval period and increasing the amount of swimming both produced carry-over effects on post-larval performance. Colonies survived at different rates among experiments, but larval experience did not affect survival rates. Delays in metamorphosis and increased swimming activity did, however, reduce colony growth rates dramatically, resulting in 50% fewer zooids per colony. Moreover, such colonies produced initial zooids with smaller feeding structures, with the width of branchial baskets reduced by 10 to 15%. These differences in branchial basket size persisted and were still apparent in newly budded zooids 3 wk after metamorphosis. Our results suggest that, for D. listerianum, larval maintenance, swimming, and metamorphosis all use energy from a common pool, and increases in the allocation to maintenance or swimming come at the expense of post-larval performance.

Structure-activity relationships of alpha-conotoxins targeting neuronal nicotinic acetylcholine receptors

alpha-Conotoxins that target the neuronal nicotinic acetylcholine receptor have a range of potential therapeutic applications and are valuable probes for examining receptor subtype selectivity. The three-dimensional structures of about half of the known neuronal specific alpha-conotoxins have now been determined and have a consensus fold containing a helical region braced by two conserved disulfide bonds. These disulfide bonds define the two-loop framework characteristic for alpha-conotoxins, CCXmCXnC, where loop 1 comprises four residues (m = 4) and loop 2 between three and seven residues (n = 3, 6 or 7). Structural studies, particularly using NMR spectroscopy have provided an insight into the role and spatial location of residues implicated in receptor binding and biological activity.

Short- and long-term, salinity-induced modulation of V-ATPase activity in the posterior gills of the true freshwater crab, Dilocarcinus pagei (Brachyura, Trichodactylidae)

To better understand the biochemical mechanisms underlying anisosmotic extracellular regulation in the freshwater Brachyura, we kinetically characterized the V-ATPase from the posterior gills of Dilocarcinus pagei, acclimated for 10 days to salinities up to 21%.. Specific activity was highest in fresh water (26.5 +/- 2.1 U mg(-1)), decreasing in 5 parts per thousand to 21 parts per thousand, attaining 3-fold less at 15 parts per thousand. Apparent affinities for ATP and Mg(2+) respectively increased 3.2- and 2-fold at 10 parts per thousand, suggesting expression of different isoenzymes. In a 240-h time-course study of exposure to 21%., maximum specific activity decreased 2.5- to 4-fold within 1 to 24 h while apparent affinities for ATP and Mg(2+) respectively increased by 12-fold within 24 h and 2.4-fold after 1 h, unchanged thereafter. K(I) for bafilomycin A(1) decreased 150-fold after 1 h, remaining constant up to 120 h. This is the first kinetic analysis of V-ATPase specific activity in crustacean gills during salinity acclimation. Our findings indicate active gill Cl(-) uptake by D. pagei in fresh water, and short- and long-term down-regulation of V-ATPase-driven ion uptake processes during salinity exposure, aiding in comprehension of the biochemical adaptations underpinning the establishment of the Brachyura in fresh water. (C) 2011 Elsevier Inc. All rights reserved.

Purification and Biochemical Properties of a Glucose-Stimulated beta-D-Glucosidase Produced by Humicola grisea var. thermoidea Grown on Sugarcane Bagasse

The effect of several carbon sources on the production of mycelial-bound beta-glucosidase by Humicola grisea var. thermoidea in submerged fermentation was investigated. Maximum production occurred when cellulose was present in the culture medium, but higher specific activities were achieved with cellobiose or sugarcane bagasse. Xylose or glucose (1%) in the reaction medium stimulated beta-glucosidase activity by about 2-fold in crude extracts from mycelia grown in sugarcane bagasse. The enzyme was purified by ammonium sulfate precipitation, followed by Sephadex G-200 and DEAE-cellulose chromatography, showing a single band in PAGE and SDS-PAGE. The beta-glucosidase had a carbohydrate content of 43% and showed apparent molecular masses of 57 and 60 kDa, as estimated by SDS-PAGE and gel filtration, respectively. The optimal pH and temperature were 6.0 and 50 degrees C, respectively. The purified enzyme was thermostable up to 60 min in water at 55 degrees C and showed half-lives of 7 and 14 min when incubated in the absence or presence of 50 mM glucose, respectively, at 60 degrees C. The enzyme hydrolyzed p-nitrophenyl-beta-D-glucopyranoside, p-nitrophenyl-beta-D-galactopyranoside, p-nitrophenyl-beta-D-fucopyranoside, p-nitrophenyl-beta-D-xylopyranoside, o-nitrophenyl-beta-D-galactopyranoside, lactose, and cellobiose. The best synthetic and natural substrates were p-nitrophenyl-beta-D-fucopyranoside and cellobiose, respectively. Purified enzyme activity was stimulated up to 2-fold by glucose or xylose at concentrations from 25 to 200 mM. The addition of purified or crude beta-glucosidase to a reaction medium containing Trichoderma reesei cellulases increased the saccharification of sugarcane bagasse by about 50%. These findings suggest that H. grisea var. thermoidea beta-glucosidase has a potential for biotechnological applications in the bioconversion of lignocellulosic materials.

Na,K-ATPase activity and epithelial interfaces in gills of the freshwater shrimp Macrobrachium amazonicum (Decapoda, Palaemonidae)

Diadromous freshwater shrimps are exposed to brackish water both as an obligatory part of their larval life cycle and during adult reproductive migration; their well-developed osmoregulatory ability is crucial to survival in such habitats. This study examines gill microsomal Na,K-ATPase (K-phosphatase activity) kinetics and protein profiles in the freshwater shrimp Macrobrachium amazonicum when in fresh water and after 10-days of acclimation to brackish water (21 parts per thousand salinity), as well as potential routes of Na(+) uptake across the gill epithelium in fresh water. On acclimation, K-phosphatase activity decreases 2.5-fold, Na,K-ATPase alpha-subunit expression declines, total protein expression pattern is markedly altered, and enzyme activity becomes redistributed into different density membrane fractions, possibly reflecting altered vesicle trafficking between the plasma membrane and intracellular compartments. Ultrastructural analysis reveals an intimately coupled pillar cell-septal cell architecture and shows that the cell membrane interfaces between the external medium and the hemolymph are greatly augmented by apical pillar cell evaginations and septal cell inviginations, respectively. These findings ire discussed regarding the putative movement of Na(+) across the pillar cell interfaces and into the hemolymph via the septal cells, powered by the Na,K-ATPase located in their invaginations. (C) 2008 Elsevier Inc. All rights reserved.

Regulation by the exogenous polyamine spermidine of Na,K-ATPase activity from the gills of the euryhaline swimming crab Callinectes danae (Brachyura, Portunidae)

Euryhaline crustaceans rarely hyporegulates and employ the driving force of the Na,K-ATPase, located at the basal surface of the gill epithelium, to maintain their hemolymph osmolality within a range compatible with cell function during hyper-regulation. Since polyamine levels increase during the adaptation of crustaceans to hyperosmotic media, we investigate the effect of exogenous polyamines on Na,K-ATPase activity in the posterior gills of Callinectes danae, a euryhaline swimming crab. Polyamine inhibition was dependent on cation concentration, charge and size in the following order: spermine > spermidine > putrescine. Spermidine affected K-0.5 values for Na+ with minor alterations in K-0.5 values for K+ and N-H-4(+), causing a decrease in maximal velocities under saturating Na+, K+ and NH4+ concentrations. Phosphorylation measurements in the presence of 20 mu M ATP revealed that the Na,K-ATPase possesses a high affinity site for this substrate. In the presence of 10 mM Na+, both spermidine and spermine inhibited formation of the phosphoenzyme; however, in the presence of 100 mM Na+, the addition of these polyamines allowed accumulation of the phosphoenzyme. The polyamines inhibited pumping activity, both by competing with Na+ at the Na+-binding site, and by inhibiting enzyme dephosphorylation. These findings suggest that polyamine-induced inhibition of Na,K-ATPase activity may be physiologically relevant during migration to fully marine environments. (c) 2008 Elsevier Inc. All rights reserved.