Role of the gp85/Trans-Sialidases in Trypanosoma cruzi Tissue Tropism: Preferential Binding of a Conserved Peptide Motif to the Vasculature In Vivo

Background: Transmitted by blood-sucking insects, the unicellular parasite Trypanosoma cruzi is the causative agent of Chagas' disease, a malady manifested in a variety of symptoms from heart disease to digestive and urinary tract dysfunctions. The reasons for such organ preference have been a matter of great interest in the field, particularly because the parasite can invade nearly every cell line and it can be found in most tissues following an infection. Among the molecular factors that contribute to virulence is a large multigene family of proteins known as gp85/trans-sialidase, which participates in cell attachment and invasion. But whether these proteins also contribute to tissue homing had not yet been investigated. Here, a combination of endothelial cell immortalization and phage display techniques has been used to investigate the role of gp85/trans-sialidase in binding to the vasculature. Methods: Bacteriophage expressing an important peptide motif (denominated FLY) common to all gp85/trans-sialidase proteins was used as a surrogate to investigate the interaction of this motif with the endothelium compartment. For that purpose phage particles were incubated with endothelial cells obtained from different organs or injected into mice intravenously and the number of phage particles bound to cells or tissues was determined. Binding of phages to intermediate filament proteins has also been studied. Findings and Conclusions: Our data indicate that FLY interacts with the endothelium in an organ-dependent manner with significantly higher avidity for the heart vasculature. Phage display results also show that FLY interaction with intermediate filament proteins is not limited to cytokeratin 18 (CK18), which may explain the wide variety of cells infected by the parasite. This is the first time that members of the intermediate filaments in general, constituted by a large group of ubiquitously expressed proteins, have been implicated in T. cruzi cell invasion and tissue homing.

Environmental stresses inhibit splicing in the aquatic fungus Blastocladiella emersonii

Background: Exposure of cells to environmental stress conditions can lead to the interruption of several intracellular processes, in particular those performed by macromolecular complexes such as the spliceosome. Results: During nucleotide sequencing of cDNA libraries constructed using RNA isolated from B. emersonii cells submitted to heat shock and cadmium stress, a large number of ESTs with retained introns was observed. Among the 6,350 ESTs obtained through sequencing of stress cDNA libraries, 181 ESTs presented putative introns (2.9%), while sequencing of cDNA libraries from unstressed B. emersonii cells revealed only 0.2% of ESTs containing introns. These data indicate an enrichment of ESTs with introns in B. emersonii stress cDNA libraries. Among the 85 genes corresponding to the ESTs that retained introns, 19 showed more than one intron and three showed three introns, with intron length ranging from 55 to 333 nucleotides. Canonical splicing junctions were observed in most of these introns, junction sequences being very similar to those found in introns from genes previously characterized in B. emersonii, suggesting that inhibition of splicing during stress is apparently a random process. Confirming our observations, analyses of gpx3 and hsp70 mRNAs by Northern blot and S1 protection assays revealed a strong inhibition of intron splicing in cells submitted to cadmium stress. Conclusion: In conclusion, data indicate that environmental stresses, particularly cadmium treatment, inhibit intron processing in B. emersonii, revealing a new adaptive response to cellular exposure to this heavy metal.

Correlation between MMPs and their inhibitors in breast cancer tumor tissue specimens and in cell lines with different metastatic potential

Background: The metastatic disease rather than the primary tumor itself is responsible for death in most solid tumors, including breast cancer. The role of matrix metalloproteinases ( MMPs), tissue inhibitors of MMPs (TIMPs) and Reversion-inducing cysteine-rich protein with Kazal motifs ( RECK) in the metastatic process has previously been established. However, in all published studies only a limited number of MMPs/MMP inhibitors was analyzed in a limited number of cell lines. Here, we propose a more comprehensive approach by analyzing the expression levels of several MMPs (MMP-2, MMP-9 and MMP-14) and MMP inhibitors (TIMP-1, TIMP-2 and RECK) in different models ( five human breast cancer cell lines, 72 primary breast tumors and 30 adjacent normal tissues). Methods: We analyzed the expression levels of MMP-2, MMP-9 and MMP-14 and their inhibitors (TIMP-1, TIMP-2 and RECK) by quantitative RT-PCR (qRT-PCR) in five human breast cancer cell lines presenting increased invasiveness and metastatic potential, 72 primary breast tumors and 30 adjacent normal tissues. Moreover, the role of cell-extracellular matrix elements interactions in the regulation of expression and activity of MMPs and their inhibitors was analyzed by culturing these cell lines on plastic or on artificial ECM (Matrigel). Results: The results demonstrated that MMPs mRNA expression levels displayed a positive and statistically significant correlation with the transcriptional expression levels of their inhibitors both in the cell line models and in the tumor tissue samples. Furthermore, the expression of all MMP inhibitors was modulated by cell-Matrigel contact only in highly invasive and metastatic cell lines. The enzyme/inhibitor balance at the transcriptional level significantly favors the enzyme which is more evident in tumor than in adjacent non-tumor tissue samples. Conclusion: Our results suggest that the expression of MMPs and their inhibitors, at least at the transcriptional level, might be regulated by common factors and signaling pathways. Therefore, the multi-factorial analysis of these molecules could provide new and independent prognostic information contributing to the determination of more adequate therapy strategies for each patient.`

The role of exon shuffling in shaping protein-protein interaction networks

Background: Physical protein-protein interaction (PPI) is a critical phenomenon for the function of most proteins in living organisms and a significant fraction of PPIs are the result of domain-domain interactions. Exon shuffling, intron-mediated recombination of exons from existing genes, is known to have been a major mechanism of domain shuffling in metazoans. Thus, we hypothesized that exon shuffling could have a significant influence in shaping the topology of PPI networks. Results: We tested our hypothesis by compiling exon shuffling and PPI data from six eukaryotic species: Homo sapiens, Mus musculus, Drosophila melanogaster, Caenorhabditis elegans, Cryptococcus neoformans and Arabidopsis thaliana. For all four metazoan species, genes enriched in exon shuffling events presented on average higher vertex degree (number of interacting partners) in PPI networks. Furthermore, we verified that a set of protein domains that are simultaneously promiscuous (known to interact to multiple types of other domains), self-interacting (able to interact with another copy of themselves) and abundant in the genomes presents a stronger signal for exon shuffling. Conclusions: Exon shuffling appears to have been a recurrent mechanism for the emergence of new PPIs along metazoan evolution. In metazoan genomes, exon shuffling also promoted the expansion of some protein domains. We speculate that their promiscuous and self-interacting properties may have been decisive for that expansion.

Synopsis and annotated checklist of Recent marine Bryozoa from Brazil

We present here a checklist of recent marine bryozoans recorded in the literature from Brazil. The total number of species recorded is 346. The most diverse group is the order Cheilostomata with 271 species, followed by the order Ctenostomata, with 42 species, and the order Cyclostomata, with 33 species. Included in the checklist are records by state and citations for species with synonyms utilized in Brazilian works.

The Influence of Different Land Uses on the Structure of Archaeal Communities in Amazonian Anthrosols Based on 16S rRNA and amoA Genes

Soil from the Amazonian region is usually regarded as unsuitable for agriculture because of its low organic matter content and low pH; however, this region also contains extremely rich soil, the Terra Preta Anthrosol. A diverse archaeal community usually inhabits acidic soils, such as those found in the Amazon. Therefore, we hypothesized that this community should be sensitive to changes in the environment. Here, the archaeal community composition of Terra Preta and adjacent soil was examined in four different sites in the Brazilian Amazon under different anthropic activities. The canonical correspondence analysis of terminal restriction fragment length polymorphisms has shown that the archaeal community structure was mostly influenced by soil attributes that differentiate the Terra Preta from the adjacent soil (i.e., pH, sulfur, and organic matter). Archaeal 16S rRNA gene clone libraries indicated that the two most abundant genera in both soils were Candidatus nitrosphaera and Canditatus nitrosocaldus. An ammonia monoxygenase gene (amoA) clone library analysis indicated that, within each site, there was no significant difference between the clone libraries of Terra Preta and adjacent soils. However, these clone libraries indicated there were significant differences between sites. Quantitative PCR has shown that Terra Preta soils subjected to agriculture displayed a higher number of amoA gene copy numbers than in adjacent soils. On the other hand, soils that were not subjected to agriculture did not display significant differences on amoA gene copy numbers between Terra Preta and adjacent soils. Taken together, our findings indicate that the overall archaeal community structure in these Amazonian soils is determined by the soil type and the current land use.

Diversity and identification of methanogenic archaea and sulphate-reducing bacteria in sediments from a pristine tropical mangrove

Mangrove sediments are anaerobic ecosystems rich in organic matter. This environment is optimal for anaerobic microorganisms, such as sulphate-reducing bacteria and methanogenic archaea, which are responsible for nutrient cycling. In this study, the diversity of these two functional guilds was evaluated in a pristine mangrove forest using denaturing gradient gel electrophoresis (DGGE) and clone library sequencing in a 50 cm vertical profile sampled every 5.0 cm. DGGE profiles indicated that both groups presented higher richness in shallow samples (0-30 cm) with a steep decrease in richness beyond that depth. According to redundancy analysis, this alteration significantly correlated with a decrease in the amount of organic matter. Clone library sequencing indicated that depth had a strong effect on the selection of dissimilatory sulphate reductase (dsrB) operational taxonomic units (OTUs), as indicated by the small number of shared OTUs found in shallow (0.0 cm) and deep (40.0 cm) libraries. On the other hand, methyl coenzyme-M reductase (mcrA) libraries indicated that most of the OTUs found in the shallow library were present in the deep library. These results show that these two guilds co-exist in these mangrove sediments and indicate important roles for these organisms in nutrient cycling within this ecosystem.

Extremal problems on sum-free sets and coverings in tridimensional spaces

Given a prime power q, define c (q) as the minimum cardinality of a subset H of F 3 q which satisfies the following property: every vector in this space di ff ers in at most 1 coordinate from a multiple of a vector in H. In this work, we introduce two extremal problems in combinatorial number theory aiming to discuss a known connection between the corresponding coverings and sum-free sets. Also, we provide several bounds on these maps which yield new classes of coverings, improving the previous upper bound on c (q)

Skewness, splitting number and vertex deletion of some toroidal meshes

The skewness sk(G) of a graph G = (V, E) is the smallest integer sk(G) >= 0 such that a planar graph can be obtained from G by the removal of sk(C) edges. The splitting number sp(G) of C is the smallest integer sp(G) >= 0 such that a planar graph can be obtained from G by sp(G) vertex splitting operations. The vertex deletion vd(G) of G is the smallest integer vd(G) >= 0 such that a planar graph can be obtained from G by the removal of vd(G) vertices. Regular toroidal meshes are popular topologies for the connection networks of SIMD parallel machines. The best known of these meshes is the rectangular toroidal mesh C(m) x C(n) for which is known the skewness, the splitting number and the vertex deletion. In this work we consider two related families: a triangulation Tc(m) x c(n) of C(m) x C(n) in the torus, and an hexagonal mesh Hc(m) x c(n), the dual of Tc(m) x c(n) in the torus. It is established that sp(Tc(m) x c(n)) = vd(Tc(m) x c(n) = sk(Hc(m) x c(n)) = sp(Hc(m) x c(n)) = vd(Hc(m) x c(n)) = min{m, n} and that sk(Tc(m) x c(n)) = 2 min {m, n}.

Understanding Pain and Quality of Life for Patients With Chronic Venous Ulcers

Aim. To identify the impact of pain on quality of life (QOL) of patients with chronic venous ulcers. Methods. A cross-sectional study was performed on 40 outpatients with chronic venous ulcers who were recruited at one outpatient care center in Sao Paulo, Brazil. WHOQOL-Bref was used to assess QOL, the McGill Pain Questionnarie-Short Form (MPQ) to identify pain characteristics, and an 11-point numerical pain rating scale to measure pain intensity. Kruskall-Wallis or ANOVA test, with post-hoc correction (Tukey test) was applied to compare groups. Multiple linear regression models were used. Results. The mean age of the patients was 67 +/- 11 years (range, 39-95 years), and 26 (65%) were women. The prevalence of pain was 90%, with worst pain mean intensity of 6.2 +/- 3.5. Severe pain was the most prevalent (21 patients, 52.5%). Pain most frequently reported was sensory-discriminative and evaluate in quality. Pain was significantly and negatively correlated with physical (PY), environmental (EV), and overall QOL. Compared to a no-pain group, those with pain had lower overall QOL. On multiple analyses, pain remained as a predictor of overall QOL (beta = -0.73, P = 0.03) and was also predictive of social QOL, whereas pain did not have any impact on physical, emotional, or social relationships QOL (beta = -3.85, P = 0.00) when adjusted for age, number, duration and frequency of wounds, pain dimension (MPQ), partnership, and economic status. Conclusion. To improve QOL of out-patients with chronic venous ulcers, the qualities and the intensity of pain must be considered differently.

Pressure Ulcer Knowledge Among Nurses in a Brazilian University Hospital

To facilitate the implementation of evidence-based skin and pressure ulcer (PU) care practices and related staff education programs in a university hospital in Brazil, a cross-sectional study was conducted to evaluate nurses` knowledge about PU prevention, wound assessment, and staging. Of the 141 baccalaureate nurses (BSN) employed by the hospital at the time of the study, 106 consented to participate. Using a Portuguese version of Pieper`s Pressure Ulcer Knowledge Test (PUKT), participants were asked to indicate whether 33 statements about PU prevention and eight about PU assessment and staging were true or false. For the 33 prevention statements, the average number answered correctly was 26.07 (SD 4.93) and for the eight assessment statements the average was 4.59 (SD 1.62). Nurses working on inpatient clinical nursing units had significantly better scores (P = 0.000). Years of nursing experience had a weak and negative correlation with correct PUKT scores (r = -0.21, P = 0.033) as did years of experience working in the university hospital (r = -.179, P <071). Incorrect responses were most common for statements related to patient positioning, massage, PU assessment, and staging definitions. The results of this study confirm that nurses have an overall understanding of PU prevention and assessment principles but important knowledge deficits exist. Focused continuing education efforts are needed to facilitate the implementation of evidence-based care.

Comparison between constant and decreasing rest intervals: influence on maximal strength and hypertrophy

de Souza Jr, TP, Fleck, SJ, Simao, R, Dubas, JP, Pereira, B, de Brito Pacheco, EM, da Silva, AC, and de Oliveira, PR. Comparison between constant and decreasing rest intervals: influence on maximal strength and hypertrophy. J Strength Cond Res 24(7): 1843-1850, 2010-Most resistance training programs use constant rest period lengths between sets and exercises, but some programs use decreasing rest period lengths as training progresses. The aim of this study was to compare the effect on strength and hypertrophy of 8 weeks of resistance training using constant rest intervals (CIs) and decreasing rest intervals (DIs) between sets and exercises. Twenty young men recreationally trained in strength training were randomly assigned to either a CI or DI training group. During the first 2 weeks of training, 3 sets of 10-12 repetition maximum (RM) with 2-minute rest intervals between sets and exercises were performed by both groups. During the next 6 weeks of training, the CI group trained using 2 minutes between sets and exercises (4 sets of 8-10RM), and the DI group trained with DIs (2 minutes decreasing to 30 seconds) as the 6 weeks of training progressed (4 sets of 8-10RM). Total training volume of the bench press and squat were significantly lower for the DI compared to the CI group (bench press 9.4%, squat 13.9%) and weekly training volume of these same exercises was lower in the DI group from weeks 6 to 8 of training. Strength (1RM) in the bench press and squat, knee extensor and flexor isokinetic measures of peak torque, and muscle cross-sectional area (CSA) using magnetic resonance imaging were assessed pretraining and posttraining. No significant differences (p <= 0.05) were shown between the CI and DI training protocols for CSA (arm 13.8 vs. 14.5%, thigh 16.6 vs. 16.3%), 1RM (bench press 28 vs. 37%, squat 34 vs. 34%), and isokinetic peak torque. In conclusion, the results indicate that a training protocol with DI is just as effective as a CI protocol over short training periods (6 weeks) for increasing maximal strength and muscle CSA; thus, either type of program can be used over a short training period to cause strength and hypertrophy.

Prevalence, magnitude, and methods of rapid weight loss among judo competitors

ARTIOLI, G. G., B. GUALANO, E. FRANCHINI, F. B. SCAGLIUSI, M. TAKESIAN, M. FUCHS, and A. H. LANCHA. Prevalence, Magnitude, and Methods of Rapid Weight Loss among Judo Competitors. Med. Sci. Sports Exerc., Vol. 42, No. 3, pp. 436-442, 2010. Purpose: To identify the prevalence, magnitude, and methods of rapid weight loss among judo competitors. Methods: Athletes (607 males and 215 females; age = 19.3 +/- 5.3 yr, weight = 70 +/- 7.5 kg, height = 170.6 +/- 9.8 cm) completed a previously validated questionnaire developed to evaluate rapid weight loss in judo athletes, which provides a score. The higher the score obtained, the more aggressive the weight loss behaviors. Data were analyzed using descriptive statistics and frequency analyses. Mean scores obtained in the questionnaire were used to compare specific groups of athletes using, when appropriate, Mann-Whitney U-test or general linear model one-way ANOVA followed by Tamhane post hoc test. Results: Eighty-six percent of athletes reported that have already lost weight to compete. When heavyweights are excluded, this percentage rises to 89%. Most athletes reported reductions of up to 5% of body weight (mean +/- SD: 2.5 +/- 2.3%). The most weight ever lost was 2%-5%, whereas a great part of athletes reported reductions of 5%-10% (mean +/- SD: 6 +/- 4%). The number of reductions underwent in a season was 3 +/- 5. The reductions usually occurred within 7 +/- 7 d. Athletes began cutting weight at 12.6 +/- 6.1 yr. No significant differences were found in the score obtained by male versus female athletes as well as by athletes from different weight classes. Elite athletes scored significantly higher in the questionnaire than nonelite. Athletes who began cutting weight earlier also scored higher than those who began later. Conclusions: Rapid weight loss is highly prevalent in judo competitors. The level of aggressiveness in weight management behaviors seems to not be influenced by the gender or by the weight class, but it seems to be influenced by competitive level and by the age at which athletes began cutting weight.

A comparative study of speed expressed by the number of throws between heavier and lighter categories in judo

Objective. - The objective of this work was to verify if there was a difference in throwing speed performance between heavier and lighter weight categories in judo. Methods and subjects. - Sixteen (16) judoists 18 +/- 3 years old, eight considered in the lightweight category (< 66 kg) and eight considered in the heavyweight (> 73 kg) category, participated in the study after signing a term of informed consent. A force-velocity test was used to determine the anaerobic power, strength, and pedal speed for each subject. In addition, three trials of Nage-komi exercise, each comprised of a set of Osoto-gari (15s), Uchi-mata (15s) and Seoi-nage (15s) throws were performed by each subject to ascertain throwing speed. Throws within the sets were intersected by one period of three minutes passive rest, while the trials were separated by one period of 10 minutes passive rest. Heart rate and the greatest number of throws within each set were measured for three trials. One-way analysis of variance (Anova) was used to compare the number of throws between the two weight categories and a ""Student"" test when the difference was significant. A correlation was used to examine the link between the different parameters. Results. - The force-velocity test did not show a significant difference in pedal speed between the two categories. However, there was a significant difference between the two categories when throwing speed was measured by the number of throws (p < 0.05) executed during the Seoi-nage (p < 0.01) and Uchi-mata (p <0.05) techniques. There was however, no significant difference between the two categories in Osoto-gari technique. Conclusion. - The throwing speed of judoists represented by the number of throws is significantly different between the two categories. The lighter category has more speed than the heavier category using the arm technique (Seoi-nage), while the heavier category has more speed using the leg technique with half turn of the attacker`s body (Uchi-mata). As a result, throwing speed is related to the type of technique used and not weight category. (C) 2007 Elsevier Masson SAS. All rights reserved.

A review of time-motion analysis and combat development in mixed martial arts matches at regional level tournaments

Mixed martial arts (MMA) have become a fast-growing worldwide expansion of martial arts competition, requiring high level of skill, physical conditioning, and strategy, and involving a synthesis of combat while standing or on the ground. This study quantified the effort-pause ratio (EP), and classified effort segments of stand-up or groundwork development to identify the number of actions performed per round in MMA matches. 52 MMA athletes participated in the study (M age = 24 yr., SD = 5; average experience in MMA = 5 yr., SD = 3). A one-way analysis of variance with repeated measurements was conducted to compare the type of action across the rounds. A chi-squared test was applied across the percentages to compare proportions of different events. Only one significant difference (p < .05) was observed among rounds: time in groundwork of low intensity was longer in the second compared to the third round. When the interval between rounds was not considered, the EP ratio (between high-intensity effort to low-intensity effort plus pauses) WE S 1:2 to 1:4. This ratio is between ratios typical for judo, wrestling, karate, and taekwondo and reflects the combination of ground and standup techniques. Most of the matches ended in the third round, involving high-intensity actions, predominantly executed during groundwork combat.