Cartilage oligomeric matrix protein is overexpressed by scleroderma dermal fibroblasts.

Cartilage oligomeric matrix protein (COMP) is an extracellular glycoprotein that belongs to the thrombospondin gene family. It is found predominantly in cartilage, tendon, ligament, and bone. Mutations in the COMP gene have been linked to the development of pseudoachondroplasia and multiple epiphysial dysplasia. COMP influences the organization of collagen fibrils by interacting with collagens I, II and IX. Gene expression profiling of cultured skin fibroblasts suggested that COMP mRNA levels were elevated in scleroderma. We therefore examined COMP expression in SSc and normal skin biopsies. Immunohistochemistry confirmed that COMP protein accumulates in SSc but not normal skin, with SSc skin showing striking deposition in the papillary and deeper dermis. Significant staining was also seen in non-lesional skin from patients. Due to its involvement in the development of fibrosis, TGFbeta was examined for a possible role in regulating COMP expression. Cultured SSc fibroblasts demonstrated greater staining for COMP compared to normal controls prior to stimulation, and TGFbeta-1 induced a large increase in mRNA and protein. Murine fibroblasts engineered to overexpress human COMP demonstrated increased levels of fibronectin and collagen in the extracellular matrix. Taken together, these data demonstrate that COMP is overexpressed in SSc skin and cultured fibroblasts possibly due to autocrine TGFbeta stimulation, and COMP overexpression is sufficient to stimulate excess matrix deposition. By interactions with other matrix proteins and cells, COMP may play a role in pathogenic matrix deposition.     

The role of selection in the evolution of human mitochondrial genomes

High mutation rate in mammalian mitochondrial DNA generates a highly divergent pool of alleles even within species that have dispersed and expanded in size recently. Phylogenetic analysis of 277 human mitochondrial genomes revealed a significant (P < 0.01) excess of rRNA and nonsynonymous base substitutions among hotspots of recurrent mutation. Most hotspots involved transitions from guanine to adenine that, with thymine-to-cytosine transitions, illustrate the asymmetric bias in codon usage at synonymous sites on the heavy-strand DNA. The mitochondrion-encoded tRNAThr varied significantly more than any other tRNA gene. Threonine and valine codons were involved in 259 of the 414 amino acid replacements observed. The ratio of nonsynonymous changes from and to threonine and valine differed significantly (P = 0.003) between populations with neutral (22/58) and populations with significantly negative Tajima's D values (70/76), independent of their geographic location. In contrast to a recent suggestion that the excess of nonsilent mutations is characteristic of Arctic populations, implying their role in cold adaptation, we demonstrate that the surplus of nonsynonymous mutations is a general feature of the young branches of the phylogenetic tree, affecting also those that are found only in Africa. We introduce a new calibration method of the mutation rate of synonymous transitions to estimate the coalescent times of mtDNA haplogroups.     

Functional proteomics approach to investigate the biological activities of cDNAs implicated in breast cancer

Functional proteomics approaches that comprehensively evaluate the biological activities of human cDNAs may provide novel insights into disease pathogenesis. To systematically investigate the functional activity of cDNAs that have been implicated in breast carcinogenesis, we generated a collection of cDNAs relevant to breast cancer, the Breast Cancer 1000 (BC1000), and conducted screens to identify proteins that induce phenotypic changes that resemble events which occur during tumor initiation and progression. Genes were selected for this set using bioinformatics and data mining tools that identify genes associated with breast cancer. Greater than 1000 cDNAs were assembled and sequence verified with high-throughput recombination-based cloning. To our knowledge, the BC1000 represents the first publicly available sequence-validated human disease gene collection. The functional activity of a subset of the BC1000 collection was evaluated in cell-based assays that monitor changes in cell proliferation, migration, and morphogenesis in MCF-10A mammary epithelial cells expressing a variant of ErbB2 that can be inducibly activated through dimerization. Using this approach, we identified many cDNAs, encoding diverse classes of cellular proteins, that displayed activity in one or more of the assays, thus providing insights into a large set of cellular proteins capable of inducing functional alterations associated with breast cancer development.     

Effects of position and flock size on vigilance and foraging behaviour of the scaled dove Columbina squammata

Amongst the benefits of foraging in flocks are the enhancement of food finding and predation avoidance. Characteristics such as size, individual position, as well as position and distance between members are factors that may influence vigilance and foraging. In a study using scaled doves, Columbina squammata, I observed a negative correlation between group size and vigilance and a positive correlation with time spent foraging, which suggests a reduction of costs and an increase of benefits as a consequence of larger group sizes. Individual position in the flock appeared to be an important factor in this trade-off. Peripheral individuals were more vigilant and foraged less than central ones, suggesting an edge effect in flocks of this species. The clustering of conspecifics may be related with fast transmission of information. Overall, aggressive interactions were rarely observed; when registered, they occurred mostly in larger groups, suggesting an effect of interference competition. These results imply that predation may be a strong pressure on the scaled dove's flock formation and behaviour.     

Antitumorigenic effect of Wnt 7a and Fzd 9 in non-small cell lung cancer cells is mediated through ERK-5-dependent activation of peroxisome proliferator-activated receptor gamma

The Wnt pathway is critical for normal development, and mutation of specific components is seen in carcinomas of diverse origins. The role of this pathway in lung tumorigenesis has not been clearly established. Recent studies from our laboratory indicate that combined expression of the combination of Wnt 7a and Frizzled 9 (Fzd 9) in Non-small Cell Lung Cancer (NSCLC) cell lines inhibits transformed growth. We have also shown that increased expression of peroxisome proliferator-activated receptor gamma (PPARgamma) inhibits transformed growth of NSCLC and promotes epithelial differentiation of these cells. The goal of this study was to determine whether the effects of Wnt 7a/Fzd 9 were mediated through PPARgamma. We found that Wnt 7a and Fzd 9 expression led to increased PPARgamma activity. This effect was not mediated by altered expression of the protein. Wnt 7a and Fzd 9 expression resulted in activation of ERK5, which was required for PPARgamma activation in NSCLC. SR 202, a known PPARgamma inhibitor, blocked the increase in PPARgamma activity and restored anchorage-independent growth in NSCLC expressing Wnt 7a and Fzd 9. SR 202 also reversed the increase in E-cadherin expression mediated by Wnt 7a and Fzd 9. These data suggest that ERK5-dependent activation of PPARgamma represents a major effector pathway mediating the anti-tumorigenic effects of Wnt 7a and Fzd 9 in NSCLC.     

A magneto-optic route toward the in vivo diagnosis of malaria: preliminary results and preclinical trial data

We report the development of magneto-optic technology for the rapid quantitative diagnosis of malaria that may also be realizable in a noninvasive format. Hemozoin, the waste product of malarial parasitic action on hemoglobin, is produced in a form that under the action of an applied magnetic field gives rise to an induced optical dichroism characteristic of the hemozoin concentration. Here we show that precise measurement of this induced dichroism may be used to determine the level of malarial infection because this correlates, albeit in a complex manner throughout the infection cycle, with the concentration of hemozoin in the blood and tissues of infected patients. Under conservative assumptions for the production of hemozoin as a function of parasitemia, initial results indicate that the technique can match or exceed other current diagnostic techniques. The validity of the approach is confirmed by a small preliminary clinical trial on 13 patients, and measurements on live parasitized cells obtained from in vitro culture verify the possibility of producing in vivo diagnostic instrumentation.     

A songbird forebrain area potentially involved in auditory discrimination and memory formation

Songbirds rely on auditory processing of natural communication signals for a number of social behaviors,including mate selection,individual recognition and the rare behavior of vocal learning - the ability to learn vocalizations through imitation of an adult model,rather than by instinct.Like mammals,songbirds possess a set of interconnected ascending and descending auditory brain pathways that process acoustic information and that are presumably involved in the perceptual processing of vocal communication signals.Most auditory areas studied to date are located in the caudomedial forebrain of the songbird and include the thalamo-recipient field L (sub fields L1,L2 and L3),the caudomedial and caudolateral mesopallium (CMM and CLM,respectively) and the caudomedial nidopallium (NCM). This review focuses on NCM,an auditory area previously proposed to be analogous to parts of the primary auditory cortex in mammals.Stimulation of songbirds with auditory stimuli drives vigorous electrophysiological responses and the expression of several activity-regulated genes in NCM.Interestingly,NCM neurons are tuned to species-specific songs and undergo some forms of experience-dependent plasticity in-vivo .These activity-dependent changes may underlie long-term modifications in the functional performance of NCM and constitute a potential neural substrate for auditory discrimination.We end this review by discussing evidence that suggests that NCM may be a site of auditory memory formation and/or storage.     

Antifungal activity of ajoene on experimental murine paracoccidioidomycosis

The natural compound ajoene (4,5,9- trithiadodeca-1,6,11-triene 9-oxide) is capable of controlling infection by Paracoccidioides brasiliensis in experimental models. Swiss mice were inoculated with 5.0 x 10e6 cells of the fungus Paracoccidioides brasiliensis Pb18 by intraperitoneal route and treated with ajoene. In weeks 2, 6, 10 and 13 of treatment, levels of anti-Pb antibodies were measured by the ELISA test and the animals were put down and their lungs, livers and spleens removed for histopathological analysis and determination of the number of viable fungus. The results show that experimental murine paracoccidioidomycosis was well established and that ajoene was capable of controlling the evolution of the disease, as it significantly reduced the levels of antibodies from the 10th week of treatment.     

S-allele diversity suggests no mate limitation in small populations of a self-incompatible plant

Small populations of self-incompatible plants are assumed to be threatened by a limitation of compatible mating partners due to low genetic diversity at the self-incompatibility (S) locus. In contrast, we show by using a PCR-RFLP approach for S-genotype identification that 15 small populations (N = 8-88) of the rare wild pear (Pyrus pyraster) displayed no mate limitation. S-allele diversity within populations was high (N = 9-21) as was mate availability (92.9-100%). Although population size and S-allele diversity were strongly related, no relationship was found between population size and mate availability, gene diversity (He), or fixation index (F(IS)), based on five neutral microsatellite loci. As we determined the principal mate availability within populations based on the S-genotypes observed, the realized mate availability under natural conditions may differ from our estimates, for example, due to spatially limited pollen dispersal. We therefore urge studies on self-incompatible plants to proceed from the simple assessment of principal mate availability to the determination of realized mate availability in natural populations.