Active Surveillance of Hansen's Disease (Leprosy): Importance for Case Finding among Extra-domiciliary Contacts

Hansen''s disease (leprosy) remains an important health problem in Brazil, where 34,894 new cases were diagnosed in 2010, corresponding to 15.3% of the world''s new cases detected in that year. The purpose of this study was to use home visits as a tool for surveillance of Hansen''s disease in a hyperendemic area in Brazil. A total of 258 residences were visited with 719 individuals examined. Of these, 82 individuals had had a previous history of Hansen''s disease, 209 were their household contacts and 428 lived in neighboring residences. Fifteen new Hansen''s disease cases were confirmed, yielding a detection rate of 2.0% of people examined. There was no difference in the detection rate between household and neighbor contacts (p = 0.615). The two groups had the same background in relation to education (p = 0.510), household income (p = 0.582), and the number of people living in the residence (p = 0.188). Spatial analysis showed clustering of newly diagnosed cases and association with residential coordinates of previously diagnosed multibacillary cases. Active case finding is an important tool for Hansen''s disease control in hyperendemic areas, enabling earlier diagnosis, treatment, decrease in disability from Hansen''s disease and potentially less spread of Mycobacterium leprae.     

B Cell Deficient Mice Are Protected from Biliary Obstruction in the Rotavirus-Induced Mouse Model of Biliary Atresia

A leading theory regarding the pathogenesis of biliary atresia (BA) is that bile duct injury is initiated by a virus infection, followed by an autoimmune response targeting bile ducts. In experimental models of autoimmune diseases, B cells have been shown to play an important role. The aim of this study was to determine the role of B cells in the development of biliary obstruction in the Rhesus rotavirus (RRV)-induced mouse model of BA. Wild-type (WT) and B cell-deficient (Ig-α^-/-) mice received RRV shortly after birth. Ig-α^-/- RRV-infected mice had significantly increased disease-free survival rate compared to WT RRV-infected BA mice (76.8% vs. 17.5%). In stark contrast to the RRV-infected BA mice, the RRV-infected Ig-α^-/- mice did not have hyperbilirubinemia or bile duct obstruction. The RRV-infected Ig-α^-/- mice had significantly less liver inflammation and Th1 cytokine production compared to RRV-infected WT mice. In addition, Ig-α^-/- mice had significantly increased numbers of regulatory T cells (Tregs) at baseline and after RRV infection compared to WT mice. However, depletion of Tregs in Ig-α^-/- mice did not induce biliary obstruction, indicating that the expanded Tregs in the Ig-α^-/- mice were not the sole reason for protection from disease. Conclusion: B cell deficient Ig-α^-/- mice are protected from biliary obstruction in the RRV-induced mouse model of BA, indicating a primary role of B cells in mediating disease pathology. The mechanism of protection may involve lack of B cell antigen presentation, which impairs T-cell activation and Th1 inflammation. Immune modulators that inhibit B cell function may be a new strategy for treatment of BA.     

Preconditioning involves selective mitophagy mediated by Parkin and p62/SQSTM1

Autophagy-dependent mitochondrial turnover in response to cellular stress is necessary for maintaining cellular homeostasis. However, the mechanisms that govern the selective targeting of damaged mitochondria are poorly understood. Parkin, an E3 ubiquitin ligase, has been shown to be essential for the selective clearance of damaged mitochondria. Parkin is expressed in the heart, yet its function has not been investigated in the context of cardioprotection. We previously reported that autophagy is required for cardioprotection by ischemic preconditioning (IPC). In the present study, we used simulated ischemia (sI) in vitro and IPC of hearts to investigate the role of Parkin in mediating cardioprotection ex vivo and in vivo. In HL-1 cells, sI induced Parkin translocation to mitochondria and mitochondrial elimination. IPC induced Parkin translocation to mitochondria in Langendorff-perfused rat hearts and in vivo in mice subjected to regional IPC. Mitochondrial depolarization with an uncoupling agent similarly induced Parkin translocation to mitochondria in cells and Langendorff-perfused rat hearts. Mitochondrial loss was blunted in Atg5-deficient cells, revealing the requirement for autophagy in mitochondrial elimination. Consistent with previous reports indicating a role for p62/SQSTM1 in mitophagy, we found that depletion of p62 attenuated mitophagy and exacerbated cell death in HL-1 cardiomyocytes subjected to sI. While wild type mice showed p62 translocation to mitochondria and an increase in ubiquitination, Parkin knockout mice exhibited attenuated IPC-induced p62 translocation to the mitochondria. Importantly, ablation of Parkin in mice abolished the cardioprotective effects of IPC. These results reveal for the first time the crucial role of Parkin and mitophagy in cardioprotection.     

Three different forms of hexokinase are identified during Tuber Borchii mycelium growth

Truffles are ectomycorrhizal fungi which have a great dependence on carbohydrates supplied by their host plants. The catabolism of hexoses in the mycobiont is important for the production of energy, and the first enzyme in the hexose assimilation pathways is hexokinase. This study reports differences in the expression of this enzyme during the growth of Tuber borchii Vittad. mycelium (strain ATCC 96540). Three hexokinase activities (HKM1, HKM2 and HKM3) were isolated by anion-exchange chromatography and partially purified. HKM1 and HKM2 were present in the linear phase at 15-50 days of growth. Two remarkable differences were found in the sugar-phosphorylating activity and stability of HKM1 and HKM2. HKM2 did not phosphorylate the fructose and it was present in the chromatographic profile only when substrates such as glucose, glucosamine or mannose were added to the extraction buffer. On the contrary, HKM1 utilized also fructose and was detected under all the experimental conditions used. HKM3 was the only molecular form observed after 70 days, when the fungus growth had reached a plateau. To our knowledge these results represent the first evidence for the presence in T. borchii mycelium of three distinct enzymatic forms of hexokinase which are differently expressed during growth of the fungus.     

Palmitate acutely raises glycogen synthesis in rat soleus muscle by a mechanism that requires its metabolization (Randle cycle)

The acute effect of palmitate on glucose metabolism in rat skeletal muscle was examined. Soleus muscles from Wistar male rats were incubated in Krebs-Ringer bicarbonate buffer, for 1 h, in the absence or presence of 10 mU/ml insulin and 0, 50 or 100 microM palmitate. Palmitate increased the insulin-stimulated [(14)C]glycogen synthesis, decreased lactate production, and did not alter D-[U-(14)C]glucose decarboxylation and 2-deoxy-D-[2,6-(3)H]glucose uptake. This fatty acid decreased the conversion of pyruvate to lactate and [1-(14)C]pyruvate decarboxylation and increased (14)CO(2) produced from [2-(14)C]pyruvate. Palmitate reduced insulin-stimulated phosphorylation of insulin receptor substrate-1/2, Akt, and p44/42 mitogen-activated protein kinases. Bromopalmitate, a non-metabolizable analogue of palmitate, reduced [(14)C]glycogen synthesis. A strong correlation was found between [U-(14)C]palmitate decarboxylation and [(14)C]glycogen synthesis (r=0.99). Also, palmitate increased intracellular content of glucose 6-phosphate in the presence of insulin. These results led us to postulate that palmitate acutely potentiates insulin-stimulated glycogen synthesis by a mechanism that requires its metabolization (Randle cycle). The inhibitory effect of palmitate on insulin-stimulated protein phosphorylation might play an important role for the development of insulin resistance in conditions of chronic exposure to high levels of fatty acids.     

Phylogeny and classification of Leptophlebiidae (Ephemeroptera) with an emphasis on Neotropical fauna

Mayflies from the family Leptophlebiidae are cosmopolitan and highly diverse morphologically; they are also the largest family in numbers of genera and the second in number of species in the order Ephemeroptera. In spite of their broad diversity and the efforts employed to understand the evolution of this group, the internal classification of Leptophlebiidae remains controversial at all levels. More recently, important changes have been incorporated into the systematics of the family, increasing the number of subfamilies (from two to six) and recognizing several tribes. We present a phylogeny of the family based on 153 taxa (53 genera) and two molecular markers, representing 1655 bp, and verify the taxonomic status of the subfamilies, tribes and complexes. Based on these results, the number of subfamilies has been increased from six to eight and one new tribes and two new subtribes have been added. In addition, new ranks are proposed and the concept of Atalophlebiinae revised, including genera with distributions in the Australasian and Neotropical regions.     

Distinctive binding of three antagonistic peptides to the ephrin-binding pocket of the EphA4 receptor

The EphA4 receptor tyrosine kinase interacts with ephrin ligands to regulate many processes, ranging from axon guidance and nerve regeneration to cancer malignancy. Thus antagonists that inhibit ephrin binding to EphA4 could be useful for a variety of research and therapeutic applications. In the present study we characterize the binding features of three antagonistic peptides (KYL, APY and VTM) that selectively target EphA4 among the Eph receptors. Isothermal titration calorimetry analysis demonstrated that all three peptides bind to the ephrin-binding domain of EphA4 with low micromolar affinity. Furthermore, the effects of a series of EphA4 mutations suggest that the peptides interact in different ways with the ephrin-binding pocket of EphA4. Chemical-shift changes observed by NMR spectroscopy upon binding of the KYL peptide involve many EphA4 residues, consistent with extensive interactions and possibly receptor conformational changes. Additionally, systematic replacement of each of the 12 amino acids of KYL and VTM identify the residues critical for EphA4, binding. The peptides exhibit a long half-life in cell culture medium which, with their substantial binding affinity and selectivity for EphA4, makes them excellent research tools to modulate EphA4 function.     

A Modular Flat Panel Photobioreactor (MFPP) for indoor mass cultivation of Nannochloropsis sp. under artificial illumination

Nannochloropsis sp. was grown in a Modular FlatPanel Photobioreactor (MFPP) consisting of sixalveolar panels each with 20.5 L culture volume and3.4 m² illuminated surface area. The panelsformed a closely-packed unit with illuminationprovided by banks of fluorescent tubes placed betweenthe panels. The whole unit was contained in athermoregulated cabinet. Continuous illumination ofone side of the panels with 115 molphoton m^-2 s^-1 attained a mean volumetricproductivity of 0.61 g (d. wt) L^-1 24 h^-1,increasing to 0.97 g (d. wt) L^-1 24 h^-1 whenthe same irradiance was provided on both sides of thepanels. With 230 mol photon m^-2 s^-1 onone side of the panel, a mean productivity of 0.85 g(d. wt) L^-1 24 h^-1 was achieved, whichreached 1.45 g (d. wt) L^-1 24 h^-1 when bothsides were illuminated. Increasing the amount of lightprovided to the culture (either by increasingirradiance or the illuminated surface area) decreasedpigment and enhanced the total fatty acid content, butdid not change significantly the content ofeicosapentaenoic acid. A MFPP of the presentdimensions could produce sufficient microalgae tosupport a hatchery producing 6 million sea breamfingerlings annually.