Atypical protein kinase Ciota plays a critical role in human lung cancer cell growth and tumorigenicity

Atypical protein kinase C (aPKC) isozymes function in epithelial cell polarity, proliferation, and survival and have been implicated in cellular transformation. However, the role of these enzymes in human cancer is largely unexplored. Here, we report that aPKCiota is highly expressed in human non-small cell lung cancer cell lines, whereas the closely related aPKC isozyme PKCzeta is undetectable in these cells. Disruption of PKCiota signaling reveals that PKCiota is dispensable for adherent growth of non-small cell lung cancer cells but is required for transformed growth in soft agar in vitro and for tumorigenicity in vivo. Molecular dissection of signaling down-stream of PKCiota demonstrates that Rac1 is a critical molecular target for PKCiota-dependent transformation, whereas PKCiota is not necessary for NFkappaB activation in vitro or in vivo. Expression of the PB1 domain of PKCiota (PKCiota-(1-113)) blocks PKCiota-dependent Rac1 activity and inhibits cellular transformation indicating a role for this domain in the transforming activity of PKCiota. Taken together, our data demonstrate that PKCiota is a critical lung cancer gene that activates a Rac1-->Pak-->Mek1,2-->Erk1,2 signaling pathway required for transformed growth. Our data indicate that PKCiota may be an attractive molecular target for mechanism-based therapies for treatment of lung cancer.     

Specific inhibition of the plasmodial surface anion channel by dantrolene

The plasmodial surface anion channel (PSAC), induced on human erythrocytes by the malaria parasite Plasmodium falciparum, is an important target for antimalarial drug development because it may contribute to parasite nutrient acquisition. However, known antagonists of this channel are quite nonspecific, inhibiting many other channels and carriers. This lack of specificity not only complicates drug development but also raises doubts about the exact role of PSAC in the well-known parasite-induced permeability changes. We recently identified a family of new PSAC antagonists structurally related to dantrolene, an antagonist of muscle Ca++ release channels. Here, we explored the mechanism of dantrolene's actions on parasite-induced permeability changes. We found that dantrolene inhibits the increased permeabilities of sorbitol, two amino acids, an organic cation, and hypoxanthine, suggesting a common pathway shared by these diverse solutes. It also produced parallel reductions in PSAC single-channel and whole-cell Cl- currents. In contrast to its effect on parasite-induced permeabilities, dantrolene had no measurable effect on five other classes of anion channels, allaying concerns of poor specificity inherent to other known antagonists. Our studies indicate that dantrolene binds PSAC at an extracellular site distinct from the pore, where it inhibits the conformational changes required for channel gating. Its affinity for this site depends on ionic strength, implicating electrostatic interactions in dantrolene binding. In addition to the potential therapeutic applications of its derivatives, dantrolene's specificity and its defined mechanism of action on PSAC make it a useful tool for transport studies of infected erythrocytes.     

Equivalence of multibreed animal models and hierarchical Bayes analysis for maternally influenced traits

Background

It has been argued that multibreed animal models should include a heterogeneous covariance structure. However, the estimation of the (co)variance components is not an easy task, because these parameters can not be factored out from the inverse of the additive genetic covariance matrix. An alternative model, based on the decomposition of the genetic covariance matrix by source of variability, provides a much simpler formulation. In this study, we formalize the equivalence between this alternative model and the one derived from the quantitative genetic theory. Further, we extend the model to include maternal effects and, in order to estimate the (co)variance components, we describe a hierarchical Bayes implementation. Finally, we implement the model to weaning weight data from an Angus × Hereford crossbred experiment.

Methods

Our argument is based on redefining the vectors of breeding values by breed origin such that they do not include individuals with null contributions. Next, we define matrices that retrieve the null-row and the null-column pattern and, by means of appropriate algebraic operations, we demonstrate the equivalence. The extension to include maternal effects and the estimation of the (co)variance components through the hierarchical Bayes analysis are then straightforward. A FORTRAN 90 Gibbs sampler was specifically programmed and executed to estimate the (co)variance components of the Angus × Hereford population.

Results

In general, genetic (co)variance components showed marginal posterior densities with a high degree of symmetry, except for the segregation components. Angus and Hereford breeds contributed with 50.26% and 41.73% of the total direct additive variance, and with 23.59% and 59.65% of the total maternal additive variance. In turn, the contribution of the segregation variance was not significant in either case, which suggests that the allelic frequencies in the two parental breeds were similar.

Conclusion

The multibreed maternal animal model introduced in this study simplifies the problem of estimating (co)variance components in the framework of a hierarchical Bayes analysis. Using this approach, we obtained for the first time estimates of the full set of genetic (co)variance components. It would be interesting to assess the performance of the procedure with field data, especially when interbreed information is limited.     

Recovery and Characterization of a 30.7-kDa Protein from Bacillus licheniformis Associated with Inhibitory Activity Against Methicillin-Resistant Staphylococcus aureus, Vancomycin-Resistant Enterococci, and Listeria monocytogenes

Of 131 bacterial isolates from seaweed, a culture of Bacillus licheniformis produced a novel protein with antibacterial activity against methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and Listeria monocytogenes. The antibacterial activity was maximal in cultures prepared in Columbia broth containing pieces of synthetic polyurethane sponge and shaken at 210 to 230 rpm. Antibacterial activity was not found in cultures grown statically or with different speeds of rotary shaking. Reduced activity was apparent in supernatants prepared from marine 2216E broth and tryptone soya broth with or without 1% (wt/vol) sodium chloride. The antibacterial compound was sensitive to proteinase K, pronase, and trypsin, but was not affected by Tween−20, −40, −60, or −80, or α− or β-amylase. Activity was not adversely affected by heating up to 40°C or treatment at pH 5 to 14. The bioactive compound was determined to be associated with a protein of 30.7 kDa, which had homology to the YbdN protein of B. licheniformis ATCC 14580.     

Preparation and characterization of polyaniline/chitosan blend film

Films consisting of a blend of a chitosan hydrogel and a conductive polymer, polyaniline (PANI), were prepared and characterized for their electrical and mechanical properties. Polyaniline in emeraldine base (EB) form was dispersed in chitosan solution and blend films were obtained by solution casting. The PANI particles in the blend films were then doped with HCl where we observed reductions in the film tensile strength and Young's modulus by about 30%, but the films electrical conductivity increased by 6 orders of magnitude. The highest electrical conductivity of the blend films was of the order 10⁻⁴ S/cm. The electrical and mechanical properties of the films varied with polyaniline content, acid dopant type, acid dopant concentration, and doping time.     

Phylogenetic analysis of the tenascin gene family: evidence of origin early in the chordate lineage

Background  

Tenascins are a family of glycoproteins found primarily in the extracellular matrix of embryos where they help to regulate cell proliferation, adhesion and migration. In order to learn more about their origins and relationships to each other, as well as to clarify the nomenclature used to describe them, the tenascin genes of the urochordate Ciona intestinalis, the pufferfish Tetraodon nigroviridis and Takifugu rubripes and the frog Xenopus tropicalis were identified and their gene organization and predicted protein products compared with the previously characterized tenascins of amniotes.     

Early HLA-B*57-Restricted CD8+ T Lymphocyte Responses Predict HIV-1 Disease Progression

Although HLA-B*57 (B57) is associated with slow progression to disease following HIV-1 infection, B57 heterozygotes display a wide spectrum of outcomes, including rapid progression, viremic slow progression, and elite control. Efforts to identify differences between B57-positive (B57(+)) slow progressors and B57(+) rapid progressors have largely focused on cytotoxic T lymphocyte (CTL) phenotypes and specificities during chronic stages of infection. Although CTL responses in the early months of infection are likely to be the most important for the long-term rate of HIV-1 disease progression, few data on the early CTL responses of eventual slow progressors have been available. Utilizing the Multicenter AIDS Cohort Study (MACS), we retrospectively examined the early HIV-1-specific CTL responses of 14 B57(+) individuals whose time to development of disease ranged from 3.5 years to longer than 25 years after infection. In general, a greater breadth of targeting of epitopes from structural proteins, especially Gag, as well as of highly conserved epitopes from any HIV-1 protein, correlated with longer times until disease. The single elite controller in the cohort was an outlier on several correlations of CTL targeting and time until disease, consistent with reports that elite control is typically not achieved solely by protective HLA-mediated CTLs. When targeting of individual epitopes was analyzed, we found that early CTL responses to the IW9 (ISPRTLNAW) epitope of Gag, while generally subdominant, correlated with delayed progression to disease. This is the first study to identify early CTL responses to IW9 as a correlate of protection in persons with HLA-B*57.