An Acid-loading Chloride Transport Pathway in the Intraerythrocytic Malaria Parasite,Plasmodium falciparum

The intraerythrocytic malaria parasite exerts tight control over its ionic composition. In this study, a combination of fluorescent ion indicators and ³⁶Cl⁻ flux measurements was used to investigate the transport of Cl⁻ and the Cl⁻-dependent transport of “H⁺-equivalents” in mature (trophozoite stage) parasites, isolated from their host erythrocytes. Removal of extracellular Cl⁻, resulting in an outward [Cl⁻] gradient, gave rise to a cytosolic alkalinization (i.e. a net efflux of H⁺-equivalents). This was reversed on restoration of extracellular Cl⁻. The flux of H⁺-equivalents was inhibited by 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid and, when measured in ATP-depleted parasites, showed a pronounced dependence on the pH of the parasite cytosol; the flux was low at cytosolic pH values < 7.2 but increased steeply with cytosolic pH at values > 7.2. ³⁶Cl⁻ influx measurements revealed the presence of a Cl⁻ uptake mechanism with characteristics similar to those of the Cl⁻-dependent H⁺-equivalent flux. The intracellular concentration of Cl⁻ in the parasite was estimated to be ∼48 mm in situ. The data are consistent with the intraerythrocytic parasite having in its plasma membrane a 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid-sensitive transporter that, under physiological conditions, imports Cl⁻ together with H⁺-equivalents, resulting in an intracellular Cl⁻ concentration well above that which would occur if Cl⁻ ions were distributed passively in accordance with the parasite''s large, inwardly negative membrane potential.     

Leishmania exosomes modulate innate and adaptive immune responses through effects on monocytes and dendritic cells

We investigated the properties of leishmania exosomes with respect to influencing innate and adaptive immune responses. Exosomes from Leishmania donovani modulated human monocyte cytokine responses to IFN-γ in a bimodal fashion by promoting IL-10 production and inhibiting that of TNF-α. Moreover, these vesicles were inhibitory with respect to cytokine responses (IL-12p70, TNF-α, and IL-10) by human monocyte-derived dendritic cells. Exosomes from wild-type (WT) L. donovani failed to prime monocyte-derived dendritic cells to drive the differentiation of naive CD4 T cells into IFN-γ-producing Th1 cells. In contrast, vesicles from heat shock protein (HSP)100(-/-) L. donovani showed a gain-of-function and proinflammatory phenotype and promoted the differentiation of naive CD4 lymphocytes into Th1 cells. Proteomic analysis showed that exosomes from WT and HSP100(-/-) leishmania had distinct protein cargo, suggesting that packaging of proteins into exosomes is dependent in part on HSP100. Treatment of C57BL/6 mice with WT L. donovani exosomes prior to challenge with WT organisms exacerbated infection and promoted IL-10 production in the spleen. In contrast, HSP100(-/-) exosomes promoted spleen cell production of IFN-γ and did not adversely affect hepatic parasite burdens. Furthermore, the proparasitic properties of WT exosomes were not species specific because BALB/c mice exposed to Leishmania major exosomes showed increased Th2 polarization and exacerbation of disease in response to infection with L. major. These findings demonstrate that leishmania exosomes are predominantly immunosuppressive. Moreover, to our knowledge, this is the first evidence to suggest that changes in the protein cargo of exosomes may influence the impact of these vesicles on myeloid cell function.     

Exotic vascular plant invasiveness and forest invasibility in urban boreal forest types

The riverine forests of the northern city of Edmonton, Alberta, Canada display strong resilience to disturbance and are similar in species composition to southern boreal mixedwood forest types. This study addressed questions such as, how easily do exotic species become established in urban boreal forests (species invasiveness) and do urban boreal forest structural characteristics such as, native species richness, abundance, and vertical vegetation layers, confer resistance to exotic species establishment and spread (community invasibility)? Eighty-four forest stands were sampled and species composition and mean percent cover analyzed using ordination methods. Results showed that exotic tree/shrub types were of the most concern for invasion to urban boreal forests and that exotic species type, native habitat and propagule supply may be good indicators of invasive potential. Native forest structure appeared to confer a level of resistance to exotic species and medium to high disturbance intensity was associated with exotic species growth and spread without a corresponding loss in native species richness. Results provided large-scale evidence that diverse communities are less vulnerable to exotic species invasion, and that intermediate disturbance intensity supports species coexistence. From a management perspective, the retention of native species and native forest structure in urban forests is favored to minimize the impact of exotic species introductions, protect natural succession patterns, and minimize the spread of exotic species.     

Crotalic and emarginellic acids: two triterpenes from Crotalaria emarginella and anti-inflammatory and anti-hepatotoxic activity of crotalic acid

The aerial parts of Crotalaria emarginella Vatke (Leguminosae) has afforded two triterpenes, characterized as 3alpha-hydroxy-arbor-12-ene-28-carboxylic acid, designated as crotalic acid (1), and 2beta,3beta,21-trihydroxy-arbor-12-ene-29-carboxylic acid, designated as emarginellic acid (2). The structures of the isolated products were elucidated on the basis of spectral and chemical studies. On screening the biological activity, the crotalic acid (1) exhibited a significant anti-inflammatory activity (dose: 10mg/kg), which showed 53% inhibitory effect. Whereas, the standard oxyphenyl butazone (100mg/kg) exhibited 69% inhibition with respect to carrageenan (0.05ml, 1%) used to cause inflammation in rat paw method. In addition, it also showed anti-hepatotoxic activity by 13-30% with respect to standard silybon-70 (35-57%) against CCl(4) induced toxicity in Wistar rats.     

The adaptive significance of sexually dimorphic scale rugosity in sea snakes

In terrestrial snakes, rugose scales are uncommon and (if they occur) generally are found on both sexes. In contrast, rugose scales are seen in most sea snakes, especially in males. Why has marine life favored this sex-specific elaboration of scale rugosity? We pose and test alternative hypotheses about the function of rugose scales in males of the turtle-headed sea snake (Emydocephalus annulatus) and conclude that multiple selective forces have been involved. First, rugosities may aid male positioning during courtship, because histology shows that tubercles are more highly innervated than adjacent flat areas of each scale and hence are presumably more sensitive to tactile cues, and because biomechanical tests show that rugosities enhance friction between the bodies of males and females. Second, the occurrence of rugosities over the entire body of males and (albeit less well developed) in females as well suggests that rugosities also play a hydrodynamic role by modifying water flow across the snake's surface. Flow tank tests show that rugosities reduce the thickness of the boundary layer by almost 50% and create turbulent flow that should massively enhance rates of cutaneous oxygen uptake and hence prolong maximal courtship duration by males.     

Expression profiling of metalloproteinases and their inhibitors in synovium and cartilage

Cartilage destruction in osteoarthritis (OA) is thought to be mediated by two main enzyme families; the matrix metalloproteinases (MMPs) are responsible for cartilage collagen breakdown, whereas enzymes from the 'a disintegrin and metalloproteinase domain with thrombospondin motifs' (ADAMTS) family mediate cartilage aggrecan loss. Tissue inhibitors of metalloproteinases (TIMPs) regulate the activity of these enzymes. Although cartilage destruction in OA might be driven by the chondrocyte, low-grade synovitis is reported in patients with all grades of this disease.     

Increase of autophagy and attenuation of apoptosis by Salvigenin promote survival of SH-SY5Y cells following treatment with H2O2

Oxidative stress is a major component of harmful cascades activated in neurodegenerative disorders. Here, we tried to elucidate the possible neuroprotective effect of Salvigenin, a natural polyphenolic compound, on oxidative stress-induced apoptosis and autophagy in human neuroblastoma SH-SY5Y cells. We measured cell viability by MTT test and found that 25?μM is the best protective concentration of Salvigenin. GSH and SOD assays suggested that Salvigenin activates antioxidant factors. At the same time, measurement of ER stress-associated proteins including calpain and caspase-12 showed the ability of Salvigenin to decrease ER stress. We found that Salvigenin could decrease the apoptotic factors. Salvigenin inhibited H₂O₂-induced caspase-3 which is a hallmark of apoptosis in addition to reducing Bax\Bcl-2 ratio by 1.45 fold. Additionally, Salvigenin increased the levels of autophagic factors. Our results showed an increase in LC3-II/LC3-I ratio, Atg7, and Atg12 in the presence of 25?μM of Salvigenin by about 1.28, 1.25, and 1.54 folds, respectively, compared to H₂O₂-treated cells. So it seems that H₂O₂ cytotoxicity mainly results from apoptosis. Besides, Salvigenin helps cells to survive by inhibiting apoptosis and enhancing autophagy that opens a new horizon for the future experiments.     

Regional inequalities in cancer care persist in Italy and can influence survival

BackgroundPopulation-based cancer registry studies of care patterns can help elucidate reasons for the marked geographic variation in cancer survival across Italy. The article provides a snapshot of the care delivered to cancer patients in Italy.MethodsRandom samples of adult patients with skin melanoma, breast, colon and non-small cell lung cancers diagnosed in 2003–2005 were selected from 14 Italian cancer registries. Logistic models estimated odds of receiving standard care (conservative surgery plus radiotherapy for early breast cancer; surgery plus chemotherapy for Dukes C colon cancer; surgery for lung cancer; sentinel node biopsy for >1 mm melanoma, vs. other treatment) in each registry compared to the entire sample (reference).ResultsStage at diagnosis for breast, colon and melanoma was earlier in north/central than southern registries. Odds of receiving standard care were lower than reference in Sassari (0.68, 95%CI 0.51–0.90) and Napoli (0.48, 95%CI 0.35–0.67) for breast cancer; did not differ across registries for Dukes C colon cancer; were higher in Romagna (3.77, 95%CI 1.67–8.50) and lower in Biella (0.38, 95%CI 0.18–0.82) for lung cancer; and were higher in Reggio Emilia (2.37, 95%CI 1.12–5.02) and lower in Ragusa (0.27, 95%CI 0.14–0.54) for melanoma.ConclusionsNotwithstanding limitations due to variations in the availability of clinical information and differences in stage distribution between north/central and southern registries, our study shows that important disparities in cancer care persist across Italy. Thus the public health priority of reducing cancer survival disparities will not be achieved in the immediate future.