p38 MAPK activation, JNK inhibition, neoplastic growth inhibition, and increased gap junction communication in human lung carcinoma and Ras-transformed cells by 4-phenyl-3-butenoic acid

Human lung neoplasms frequently express mutations that down‐regulate expression of various tumor suppressor molecules, including mitogen‐activated protein kinases such as p38 MAPK. Conversely, activation of p38 MAPK in tumor cells results in cancer cell cycle inhibition or apoptosis initiated by chemotherapeutic agents such as retinoids or cisplatin, and is therefore an attractive approach for experimental anti‐tumor therapies. We now report that 4‐phenyl‐3‐butenoic acid (PBA), an experimental compound that reverses the transformed phenotype at non‐cytotoxic concentrations, activates p38 MAPK in tumorigenic cells at concentrations and treatment times that correlate with decreased cell growth and increased cell‐cell communication. H2009 human lung carcinoma cells and ras‐transformed rat liver epithelial cells treated with PBA showed increased activation of p38 MAPK and its downstream effectors which occurred after 4 h and lasted beyond 48 h. Untransformed plasmid control cells showed low activation of p38 MAPK compared to ras‐transformed and H2009 carcinoma cells, which correlates with the reduced effect of PBA on untransformed cell growth. The p38 MAPK inhibitor, SB203580, negated PBA's activation of p38 MAPK downstream effectors. PBA also increased cell–cell communication and connexin 43 phosphorylation in ras‐transformed cells, which were prevented by SB203580. In addition, PBA decreased activation of JNK, which is upregulated in many cancers. Taken together, these results suggest that PBA exerts its growth regulatory effect in tumorigenic cells by concomitant up‐regulation of p38 MAPK activity, altered connexin 43 expression, and down‐regulation of JNK activity. PBA may therefore be an effective therapeutic agent in human cancers that exhibit down‐regulated p38 MAPK activity and/or activated JNK and altered cell–cell communication. J. Cell. Biochem. 113: 269–281, 2012. © 2011 Wiley Periodicals, Inc.     

Dietary fructose inhibits lactation-induced adaptations in rat 1,25-(OH)?D? synthesis and calcium transport

We recently showed that excessive fructose consumption, already associated with numerous metabolic abnormalities, reduces rates of intestinal Ca(2+) transport. Using a rat lactation model with increased Ca(2+) requirements, we tested the hypothesis that mechanisms underlying these inhibitory effects of fructose involve reductions in renal synthesis of 1,25-(OH)(2)D(3). Pregnant and virgin (control) rats were fed isocaloric fructose or, as controls, glucose, and starch diets from d 2 of gestation to the end of lactation. Compared to virgins, lactating dams fed glucose or starch had higher rates of intestinal transcellular Ca(2+) transport, elevated intestinal and renal expression of Ca(2+) channels, Ca(2+)-binding proteins, and CaATPases, as well as increased levels of 25-(OH)D(3) and 1,25-(OH)(2)D(3). Fructose consumption prevented almost all of these lactation-induced increases, and reduced vitamin D receptor binding to promoter regions of Ca(2+) channels and binding proteins. Changes in 1,25-(OH)(2)D(3) level were tightly correlated with alterations in expression of 1α-hydroxylase but not with levels of parathyroid hormone and of 24-hydroxylase. Bone mineral density, content, and mechanical strength each decreased with lactation, but then fructose exacerbated these effects. When Ca(2+) requirements increase during lactation or similar physiologically challenging conditions, excessive fructose consumption may perturb Ca(2+) homeostasis because of fructose-induced reductions in synthesis of 1,25-(OH)(2)D(3).     

Acute impact of intermittent pneumatic leg compression frequency on limb hemodynamics, vascular function, and skeletal muscle gene expression in humans

The mechanisms by which intermittent pneumatic leg compression (IPC) treatment effectively treats symptoms associated with peripheral artery disease remain speculative. With the aim of gaining mechanistic insight into IPC treatment, the purpose of this study was to investigate the effect of IPC frequency on limb hemodynamics, vascular function, and skeletal muscle gene expression. In this two study investigation, healthy male subjects underwent an hour of either high-frequency (HF; 2-s inflation/3-s deflation) or low-frequency (LF; 4-s inflation/16-s deflation) IPC treatment of the foot and calf. In study 1 (n = 11; 23.5 ± 4.7 yr), subjects underwent both HF and LF treatment on separate days. Doppler/ultrasonography was used to measure popliteal artery diameter and blood velocity at baseline and during IPC treatment. Flow-mediated dilation (FMD) and peak reactive hyperemia blood flow (RHBF) were determined before and after IPC treatment. In study 2 (n = 19; 22.0 ± 4.6 yr), skeletal muscle biopsies were taken from the lateral gastrocnemius of the treated and control limb at baseline and at 30- and 150-min posttreatment. Quantitative PCR was used to assess mRNA concentrations of genes associated with inflammation and vascular remodeling. No treatment effect on vascular function was observed. Cuff deflation resulted in increased blood flow (BF) and shear rate (SR) in both treatments at the onset of treatment compared with baseline (P < 0.01). BF and SR significantly diminished by 45 min of HF treatment only (P < 0.01). Both treatments reduced BF and SR and elevated oscillatory shear index compared with baseline (P < 0.01) during cuff inflation. IPC decreased the mRNA expression of cysteine-rich protein 61 from baseline and controls (P <0 .01) and connective tissue growth factor from baseline (P < 0.05) in a frequency-dependent manner. In conclusion, a single session of IPC acutely impacts limb hemodynamics and skeletal muscle gene expression in a frequency-dependent manner but does not impact vascular function.     

Role of rpoS in Escherichia coli O157:H7 Strain H32 Biofilm Development and Survival

The protein RpoS is responsible for mediating cell survival during the stationary phase by conferring cell resistance to various stressors and has been linked to biofilm formation. In this study, the role of the rpoS gene in Escherichia coli O157:H7 biofilm formation and survival in water was investigated. Confocal scanning laser microscopy of biofilms established on coverslips revealed a nutrient-dependent role of rpoS in biofilm formation, where the biofilm biomass volume of the rpoS mutant was 2.4- to 7.5-fold the size of its rpoS⁺ wild-type counterpart in minimal growth medium. The enhanced biofilm formation of the rpoS mutant did not, however, translate to increased survival in sterile double-distilled water (ddH₂O), filter-sterilized lake water, or unfiltered lake water. The rpoS mutant had an overall reduction of 3.10 and 5.30 log₁₀ in sterile ddH₂O and filter-sterilized lake water, respectively, while only minor reductions of 0.53 and 0.61 log₁₀ in viable counts were observed for the wild-type form in the two media over a 13-day period, respectively. However, the survival rates of the detached biofilm-derived rpoS⁺ and rpoS mutant cells were comparable. Under the competitive stress conditions of unfiltered lake water, the advantage conferred by the presence of rpoS was lost, and both the wild-type and knockout forms displayed similar declines in viable counts. These results suggest that rpoS does have an influence on both biofilm formation and survival of E. coli O157:H7 and that the advantage conferred by rpoS is contingent on the environmental conditions.     

Vitamins A & D inhibit the growth of mycobacteria in radiometric culture

Background

The role of vitamins in the combat of disease is usually conceptualized as acting by modulating the immune response of an infected, eukaryotic host. We hypothesized that some vitamins may directly influence the growth of prokaryotes, particularly mycobacteria.

Methods

The effect of four fat-soluble vitamins was studied in radiometric Bactec® culture. The vitamins were A (including a precursor and three metabolites,) D, E and K. We evaluated eight strains of three mycobacterial species (four of M. avium subspecies paratuberculosis (MAP), two of M. avium and two of M. tb. complex).

Principal Findings

Vitamins A and D cause dose-dependent inhibition of all three mycobacterial species studied. Vitamin A is consistently more inhibitory than vitamin D. The vitamin A precursor, β-carotene, is not inhibitory, whereas three vitamin A metabolites cause inhibition. Vitamin K has no effect. Vitamin E causes negligible inhibition in a single strain.

Significance

We show that vitamin A, its metabolites Retinyl acetate, Retinoic acid and 13-cis Retinoic acid and vitamin D directly inhibit mycobacterial growth in culture. These data are compatible with the hypothesis that complementing the immune response of multicellular organisms, vitamins A and D may have heretofore unproven, unrecognized, independent and probable synergistic, direct antimycobacterial inhibitory activity.     

Temporal Variation in Seed Predation by Insects in a Population of Syagrus romanzoffiana (Arecaceae) in Santa Catarina Island, SC, Brazil

Insect seed predation may vary depending on seed production. The present study considers the hypothesis that the rates of seed predation tend to be smaller in years of higher fruit production. Thus, we monitored the production of fruits and predation of seeds of the palm Syagrus romanzoffiana over 2?years in the Atlantic Forest (Parque Municipal da Lagoa do Peri, Florianópolis, SC, Brazil), between July 2006 and June 2008. Plots of 0.25?m² were fitted under 20 mother plants and fruits were monthly collected for assessment of abundance and seed predation. There was variation in fruit production between the 2?years and among reproductive plants. Predation rates were high and occurred in the predispersal phase by the Curculionidae Revena rubiginosa Boheman, Anchylorhynchus aegrotus Fahraeus, and Anchylorhynchus variabilis Gyllenhal. Seed predation by these species of Anchylorhynchus is first registered in the present study. In average, about 60% of the seeds monthly produced in the population tend to escape insect predation in year of high or low production, becoming available for recruitment. The predation rate was not related to the amount of fruits produced per reproductive plant. Also, different than expected, there was a positive relation between the rates of seed predation and the total of fruits produced monthly on the plots. Thus, no evidence for the satiation of insect seed predators was found in this study with S. romanzoffiana.     

Elevated summer temperatures delay spawning and reduce redd construction for resident brook trout (Salvelinus fontinalis)

Redd (nest) surveys for resident brook trout (Salvelinus fontinalis) were conducted annually in a mountain lake in northern New York for 11 years with multiple surveys conducted during the spawning season in eight of those years. Repeated surveys throughout the spawning season allowed us to fit an individually based parametric model and estimate the day of year on which spawning was initiated, reached its midpoint, and ended during each year. Spawning phenology was then assessed relative to (1) mean of maximum daily air temperature and (2) mean of maximum daily water temperature at the lake bottom during summer in each year using a linear model. Elevated temperatures in summer were correlated with a delay in spawning and a reduction in the total number of redds constructed. Increasing the summer mean of maximum daily air temperatures by 1 °C delayed spawning by approximately 1 week and decreased the total number of redds constructed by nearly 65. Lake spawning brook trout select redd sites based on the presence of discharging groundwater that is relatively constant in temperature within and across years, leading to relatively consistent egg incubation times. Therefore, delayed spawning is likely to delay fry emergence, which could influence emergence synchrony with prey items. This work highlights non‐lethal and sub‐lethal effects of elevated summer temperatures on native resident salmonids in aquatic environments with limited thermal refugia.     

Encapsulation of Pseudomonas sp. ADP cells in electrospun microtubes for atrazine bioremediation

Electrospun hollow polymeric microfibers (microtubes) were evaluated as an encapsulation method for the atrazine degrading bacterium Pseudomonas sp. ADP. Pseudomonas sp. ADP cells were successfully incorporated in a formulation containing a core solution of polyethylene oxide dissolved in water and spun with an outer shell solution made of polycaprolactone and polyethylene glycol dissolved in a chloroform and dimethylformamide. The resulting microtubes, collected as mats, were partially collapsed with a ribbon-like structure. Following encapsulation, the atrazine degradation rate was low (0.03?±?0.01?mg atrazine/h/g fiber) indicating that the electrospinning process negatively affected cell activity. Atrazine degradation was restored to 0.5?±?0.1?mg atrazine/h/g fiber by subjecting the microtubes to a period of growth. After 3 and 7?days growth periods, encapsulated cells were able to remove 20.6?±?3 and 47.6?±?5.9?mg atrazine/g mat, respectively, in successive batches under non-growth conditions (with no additional electron donor) until atrazine was detected in the medium. The loss of atrazine degrading capacity was regained following an additional cell-growth period.     

Species trees for the tree swallows (Genus Tachycineta): An alternative phylogenetic hypothesis to the mitochondrial gene tree

The New World swallow genus Tachycineta comprises nine species that collectively have a wide geographic distribution and remarkable variation both within- and among-species in ecologically important traits. Existing phylogenetic hypotheses for Tachycineta are based on mitochondrial DNA sequences, thus they provide estimates of a single gene tree. In this study we sequenced multiple individuals from each species at 16 nuclear intron loci. We used gene concatenated approaches (Bayesian and maximum likelihood) as well as coalescent-based species tree inference to reconstruct phylogenetic relationships of the genus. We examined the concordance and conflict between the nuclear and mitochondrial trees and between concatenated and coalescent-based inferences. Our results provide an alternative phylogenetic hypothesis to the existing mitochondrial DNA estimate of phylogeny. This new hypothesis provides a more accurate framework in which to explore trait evolution and examine the evolution of the mitochondrial genome in this group.