Purification and inflammatory edema induced by two PLA2 (Anch TX-I and Anch TX-II) from sea anemone Anthothoe chilensis (Actiniaria: Sagartiidae)

The Anch TX-I and II PLA₂ were purified from Anthothoe chilensis (Lesson, 1830) from the extract of the anemone after only two chromatographic step using molecular exclusion chromatography (Sephadex G-75) and reverse phase HPLC on μ-Bondapak C18 column. Both PLA₂ showed a molecular mass of ~ 14 kDa determined by MALDI-TOF mass spectrometry and showed a high catalytic activity (data not showed). Although homologous with mammalian or snake venom group I PLA₂s, Anch TX-I and II is sufficiently structurally different for the question of its placement into the existing PLA₂ classification scheme to arise. In addition, Anch TX-I and II, despite possessing many common structural features, also differ in some important structural properties. The amino acid sequence of both PLA₂ (Anch TX-I and III) showed high amino acid sequence identity with PLA₂Rhopilema nomadica and Bunodosoma caissarum Cnidaria and PLA₂ of group III protein isolated from the Mexican lizard Heloderma horridum horridum and Heloderma suspectum. In addition, Anch TX-I and Anch TX-II showed high amino acid sequence identity with PLA₂ from group III also showed significant overall homology to bee Apis dorsata, Bombus terrestris and Bombus pennsylvanicus and PLA₂. We also investigated the in vivo edematogenic activity of Anch TX-I and Anch TX-II in a model of paw and skin edema in rats and observed that both are able to induce dose-dependent edema.     

Overexpression of inducible 70-kDa heat shock protein in mouse attenuates skeletal muscle damage induced by cryolesioning

Heat shock protein expression is elevated upon exposure to a variety of stresses and limits the extent of stress-induced damage. To investigate the putative role of inducible 70-kDa heat shock protein (HSP70) in skeletal muscle damage and regeneration, soleus and tibialis anterior (TA) muscles from HSP70-overexpressing transgenic mice were subjected to cryolesioning and analyzed after 1, 10, and 21 days. Histological analysis showed that the muscles from both HSP70 and wild-type mice treated with radicicol (a HSP inducer) had decreased necrosis after cryolesioning compared with controls. The decrease in muscle fiber cross-sectional area in both soleus and TA muscles in 10 days postlesioning was attenuated in HSP70 mice compared with wild-type mice. Glutathione peroxidase activity was increased 1 day after cryolesioning in both HSP70 and control mice and remained elevated for up to 21 days. Immunodetection of neuronal cell adhesion molecule (a satellite cell marker) and developmental/neonatal MHC were significantly lower in cryolesioned HSP70-overexpressing mice than in cryolesioned controls. These results suggest that HSP70 protects skeletal muscle against injury and radicicol might be useful as a skeletal muscle protective agent. regeneration; radicicol; transgenic mouse; myoprotection     

Faunistic analysis of fruit flies (Diptera: Tephritidae) in the Northern and Northwestern Regions of Rio de Janeiro State, Brazil

This study aimed to characterize the fruit fly populations in three municipalities of the Northern region and two municipalities of the Northwestern region of Rio de Janeiro State, Brazil, and to evaluate the similarity among their populations. A faunistic analysis was performed from the fruit fly specimens captured in plastic McPhail traps with an aqueous solution of hydrolyzed protein to 5% placed in orchards of guava (Psidium guajava L.) and/or other fruits during 26 months. The total of 3,952 females of 15 species of Anastrepha Schiner and 277 females of Ceratitis capitata (Wied.) was captured. The species richness differed among the municipalities, with the highest value in S?o Francisco do Itabapoana (S = 14), resulting on the highest Shannon-Wiener index (H = 1.27). The equitability was low in the five municipalities due to the dominance of one unique fruit fly species. The predominant species (more frequent, constant and dominant) were Anastrepha obliqua (Macquart) in Campos dos Goytacazes and S?o Francisco do Itabapoana, Anastrepha fraterculus (Wied.) in Cambuci and Itaocara, and Anastrepha sororcula Zucchi in S?o Jo?o da Barra. Fruit fly populations had low diversity index of Margalef (alpha = 0.58 to 1.82). Regarding to fruit fly species composition, the populations in S?o Jo?o da Barra and Cambuci were more similar between each other, composing a distinct group from the populations in Campos dos Goytacazes and Itaocara. These two groups differed quite a lot from the population in S?o Francisco do Itabapoana.     

Deconstructing tick saliva: non-protein molecules with potent immunomodulatory properties

Dendritic cells (DCs) are powerful initiators of innate and adaptive immune responses. Ticks are blood-sucking ectoparasite arthropods that suppress host immunity by secreting immunomodulatory molecules in their saliva. Here, compounds present in Rhipicephalus sanguineus tick saliva with immunomodulatory effects on DC differentiation, cytokine production, and costimulatory molecule expression were identified. R. sanguineus tick saliva inhibited IL-12p40 and TNF-α while potentiating IL-10 cytokine production by bone marrow-derived DCs stimulated by Toll-like receptor-2, -4, and -9 agonists. To identify the molecules responsible for these effects, we fractionated the saliva through microcon filtration and reversed-phase HPLC and tested each fraction for DC maturation. Fractions with proven effects were analyzed by micro-HPLC tandem mass spectrometry or competition ELISA. Thus, we identified for the first time in tick saliva the purine nucleoside adenosine (concentration of ～110 pmol/μl) as a potent anti-inflammatory salivary inhibitor of DC cytokine production. We also found prostaglandin E(2) (PGE(2) ～100 nM) with comparable effects in modulating cytokine production by DCs. Both Ado and PGE(2) inhibited cytokine production by inducing cAMP-PKA signaling in DCs. Additionally, both Ado and PGE(2) were able to inhibit expression of CD40 in mature DCs. Finally, flow cytometry analysis revealed that PGE(2), but not Ado, is the differentiation inhibitor of bone marrow-derived DCs. The presence of non-protein molecules adenosine and PGE(2) in tick saliva indicates an important evolutionary mechanism used by ticks to subvert host immune cells and allow them to successfully complete their blood meal and life cycle.     

Testing for biogeographic mechanisms promoting divergence in Caribbean crickets (genus Amphiacusta)

Aim This work examines whether the history of diversification of Amphiacusta (Orthoptera, Gryllidae) in the Caribbean corresponds to a vicariant or a dispersalist model. Location The Greater Antillean islands of the Caribbean region. Methods The phylogenetic relationships among species were estimated using a procedure that directly estimates the underlying species tree from independent loci (in this case, one mitochondrial and one nuclear locus). This tree was then used to test for topological congruence with a vicariant model, and to estimate divergence times. Results The analyses based on the expected pattern of species divergence (i.e. species‐tree topology) support a vicariant model. With the notable exception of a dispersal event marking the colonization of Jamaica, the timing of the events are generally consistent with a vicariant scenario, given the current taxon sampling and potential errors with dating the divergence events. Main conclusions The tendency of species to co‐segregate by island suggests that intra‐island diversification is common. Despite their flightlessness, species of Amphiacusta are apparently capable of long‐distance dispersal, such as colonization from the Puerto Rican/Virgin Island bank to Jamaica. The topology of the species tree is consistent with a vicariant model of divergence, and the dates of divergence between island groups are generally consistent with an island–island vicariance model. A strict island–island vicariance scenario can, however, be rejected because of inferred dispersal events such as the colonization of Jamaica. Nevertheless, the biogeographic tests suggest that most of the diversity was generated under a combination of intra‐island diversification and island–island vicariance. Additional sampling of taxa will be needed to verify this hypothesized scenario. Our findings indicate that Amphiacusta presents an ideal opportunity for examining the role of sexual selection in promoting diversification, which would complement the large number of studies focused on adaptive divergence of Caribbean taxa.     

Characterization, chromosomal assignment, and role of LIFR in early embryogenesis and stem cell establishment of rabbits

Leukemia inhibitory factor (LIF) is a multifunctional cytokine with an important role during early embryonic development, implantation, and as an inhibitor of murine embryonic stem cell differentiation. It exerts its effects by binding to the leukemia inhibitory factor receptor, a heterodimer of two transmembrane proteins, the specific leukemia inhibitory factor receptor subunit, and the common gp130. A partial cDNA clone coding for the membrane-bound form of the specific rabbit leukemia inhibitory factor receptor was isolated from the genital ridge of 13.5 days postcoitum fetus. Fluorescent in situ hybridization analysis revealed that the rabbit leukemia inhibitory factor receptor gene is located on chromosome OCU11p11.1. It has been shown that the membrane-bound rabbit leukemia inhibitory factor receptor mRNA is expressed during embryo implantation but not at earlier developmental stages. Rabbit embryonic stem cell-like line establishment is improved in the presence of LIF, and those cells express both leukemia inhibitory factor and its receptor. The withdrawal of leukemia inhibitory factor results the differentiation of embryonic stem cell-like cells to beating myocardial-like cells. Our findings suggest that the self-renewal mechanism is similar in mouse and rabbit embryonic stem cells, and expands our knowledge on the role of the LIF-LIFR signal pathway in early rabbit embryogenesis and rabbit embryonic stem cell establishment.     

Acute Chagas Disease Induces Cerebral Microvasculopathy in Mice

Cardiomyopathy is the main clinical form of Chagas disease (CD); however, cerebral manifestations, such as meningoencephalitis, ischemic stroke and cognitive impairment, can also occur. The aim of the present study was to investigate functional microvascular alterations and oxidative stress in the brain of mice in acute CD. Acute CD was induced in Swiss Webster mice (SWM) with the Y strain of Trypanosoma cruzi (T. cruzi). Cerebral functional capillary density (the number of spontaneously perfused capillaries), leukocyte rolling and adhesion and the microvascular endothelial-dependent response were analyzed over a period of fifteen days using intravital video-microscopy. We also evaluated cerebral oxidative stress with the thiobarbituric acid reactive species TBARS method. Compared with the non-infected group, acute CD significantly induced cerebral functional microvascular alterations, including (i) functional capillary rarefaction, (ii) increased leukocyte rolling and adhesion, (iii) the formation of microvascular platelet-leukocyte aggregates, and (iv) alteration of the endothelial response to acetylcholine. Moreover, cerebral oxidative stress increased in infected animals. We concluded that acute CD in mice induced cerebral microvasculopathy, characterized by a reduced incidence of perfused capillaries, a high number of microvascular platelet-leukocyte aggregates, a marked increase in leukocyte-endothelium interactions and brain arteriolar endothelial dysfunction associated with oxidative stress. These results suggest the involvement of cerebral microcirculation alterations in the neurological manifestations of CD.