5′-Nucleotidase activity in the pineal organ of the pike

Summary To date, it is still unknown whether the metabolism of purine nucleotides and nucleosides plays an important role in the pineal organ of lower vertebrates. We have therefore investigated the sites of 5-nucleotidase activity in the pineal organ of the pike (Esox lucius L.). Various ultracytochemical procedures were used. An intense ecto-5-nucleotidase activity was characteristic of the entire plasma membrane of the phototransducers (cone-like and modified photoreceptor elements) and the interstitial cells, with exception of the portions facing the basal lamina of the pericapillary spaces. Additionally, intracellular sites of activity were also visualized in the inner segment and the pedicle of the phototransducers. Most of the intracellular deposits were apparently cytosolic and only few seemed to be associated with the membrane of the clear synaptic vesicles of the pedicle. Phagocytotic cells in the pineal lumen also showed a strong enzymatic activity on the outer surface of their plasmalemma (in ectoposition). This was apparently not the case for the cell types of the tissues surrounding the pineal vesicle. The present study emphasizes the importance of the occurrence and metabolism of purine nucleotides and nucleosides in a photoreceptive pineal organ.     

Running demands and activity profile of men’s rugby sevens: a tournament scenario

This study profiled the changes in running performances and collisions within a Rugby sevens tournament. Sixteen male players were equipped with global positioning system units while competing at the 2015 and 2016 Asia Rugby Sevens series held in Colombo and Hong Kong, respectively. Both tournaments consisted of 4 matches each, and were played over 2 days (i.e., 2 matches/day). Total distance (TD) covered increased in match 3 compared with matches 1 (19 ± 19%; p < 0.001) and 2 (16 ± 11%; p = 0.001), whilst a decrease in TD in match 4 compared with match 3 (8 ± 9%; p = 0.019) was observed. Distances covered within 6.1–12 km·h^-1 and 12.1–14 km·h^-1 speed bands were generally higher in matches 3 and/or 4 when compared with match 1 and/or 2 (p < 0.05). Frequency of entries into 14.1–18 km·h^-1 speed zone was decreased in match 4 compared with match 3 (45 ± 41%; p = 0.009), whilst incidences of heavy, very heavy and severe collisions were generally higher in matches 3 or 4 compared with matches 1 or 2 (p < 0.05). In conclusion, while some decrements in the final match were evident, running performance were generally maintained throughout despite the competitive and congested nature of Rugby Sevens tournaments     

Biomechanical remodeling of the microenvironment by stromal caveolin-1 favors tumor invasion and metastasis

Mechanotransduction is a key determinant of tissue homeostasis and tumor progression. It is driven by intercellular adhesions, cell contractility, and forces generated within the microenvironment and is dependent on extracellular matrix composition, organization, and compliance. We show that caveolin-1 (Cav1) favors cell elongation in three-dimensional cultures and promotes Rho- and force-dependent contraction, matrix alignment, and microenvironment stiffening through regulation of p190RhoGAP. In turn, microenvironment remodeling by Cav1 fibroblasts forces cell elongation. Cav1-deficient mice have disorganized stromal tissue architecture. Stroma associated with human carcinomas and melanoma metastases is enriched in Cav1-expressing carcinoma-associated fibroblasts (CAFs). Cav1 expression in breast CAFs correlates with low survival, and Cav1 depletion in CAFs decreases CAF contractility. Consistently, fibroblast expression of Cav1, through p190RhoGAP regulation, favors directional migration and invasiveness of carcinoma cells in vitro. In vivo, stromal Cav1 remodels peri- and intratumoral microenvironments to facilitate tumor invasion, correlating with increased metastatic potency. Thus, Cav1 modulates tissue responses through force-dependent architectural regulation of the microenvironment.     

Assessment of organochlorine pesticides and metals in ring‐tailed lemurs (Lemur catta) at Beza Mahafaly Special Reserve,Madagascar

Like most of Madagascar's endemic primates, ring‐tailed lemurs (Lemur catta) face a number of threats to their survival. Although habitat loss is of greatest concern, other anthropogenic factors including environmental contamination may also affect lemur health and survival. In this study, we examined ring‐tailed lemurs from the Beza Mahafaly Special Reserve (BMSR), southern Madagascar for exposure to organochlorine (OC) pesticides and metals and examined differences in contaminant concentrations between sexes and among age groups, troops, and habitats. A total of 14 pesticides and 13 metals was detected in lemur blood (24 individuals) and hair (65 individuals) samples, respectively. p,p′‐DDT, heptachlor, aldrin, heptachlor epoxide, endrin aldehyde, and endrin were among the most prevalent pesticides detected. Surprisingly, the persistent metabolite of p,p′‐DDT, p,p′‐DDE, was not detected. The most commonly detected metals were aluminum, zinc, boron, phosphorus, silicon, and copper, whereas metals considered more hazardous to wildlife (e.g. arsenic, cadmium, lead, selenium, vanadium) were not found above detection limits. Overall, concentrations of OC pesticides and metals were low and similar to those considered to be background concentrations in other studies examining the ecotoxicology of wild mammals. Few inter‐sex, ‐age, ‐troop, and ‐habitat differences in contaminant concentrations were observed, suggesting a uniform distribution of contaminants within the reserve. Several statistically significant relationships between lemur body size and contaminant concentrations were observed, but owing to the lack of supportive data regarding contaminant exposure in wild primates, the biological significance of these findings remains uncertain. Results of this study document exposure of ring‐tailed lemurs at BMSR to multiple OC pesticides and metals and provide essential baseline data for future health and toxicological evaluations of lemurs and other wild primates, especially those in regions with expanding agricultural and mining operations. Am. J. Primatol. 71:998–1010, 2009. © 2009 Wiley‐Liss, Inc.     

Crystallization and prelilminary X-ray investigation of barster,the intracellular inhibitor of barnase

Crystals of barstar, the intracellular inhibitor of the extracellular ribonuclease produced by Bacillus amyloliquefaciens (barnase), were obtained through vapor phase equilibration using the hanging drop technique. Three crystal forms have been characterized. Forms I and II, crystallized eithr in potetragonal; they exhibit a superstructure along the c-axis. Form III crystals, suitable for a high resolution structure determination, were grown from 55-65% ammomnium sulfate. This crystal form is hexagonal and diffracts to at least 2 Å resolution at a synchrotron radiation source. It belongs to the hexagonal space group P6, with unit cell dimensions a = b = 143.6 Å, c = 35.6 Å. There are four molecules of barstar in the asymmetric unit. X-ray data have been collected to 2.2 Å Bragg sapcing. The structure determination is underway in order to analyze conformational changes of barstar upon complexation with barnas. © 1993 Wiley-Liss, Inc.