Long-term feeding a high-fat diet causes histological and parasitological effects on murine schistosomiasis mansoni outcome

This study investigated whether long-term feeding a high-fat diet (HFC) has an effect on schistosomiasis mansoni outcome compared to standard chow diet (SC). Swiss Webster female mice (3 wk old) fed each diet over 5 months, and then were infected with 50 Schistosoma mansoni cercariae. Their nutritional status was assessed by monitoring growth rates twice a week and measuring serum levels of lipoproteins. Mice were euthanised 63 days after infection. Parasitological and liver histological analyses were performed. The levels of TC, HDL-C and LDL-C, fecal and tissue schistosome eggs were statistically different (p<0.05) between groups. Livers from HFC mice showed exudative, exudative/exudative-productive, exudative-productive and productive granulomas, some degree of hepatic steatosis and focal necrosis. Mice fed normal-chow did not present productive granulomas and hepatic steatosis. The morphometric evaluation of hepatic granulomas did not reach statistical significance (p>0.05) between diets assayed. The high-fat diet for long-term produces effects on schistosomiasis mansoni outcome.     

The lactate dehydrogenases encoded by the ldh and ldhB genes in Lactococcus lactis exhibit distinct regulation and catalytic properties - comparative modeling to probe the molecular basis

Lactococcus lactis FI9078, a construct carrying a disruption of the ldh gene, converted approximately 90% of glucose into lactic acid, like the parental strain MG1363. This unexpected lactate dehydrogenase activity was purified, and ldhB was identified as the gene encoding this protein. The activation of ldhB was explained by the insertion of an IS905-like element that created a hybrid promoter in the intergenic region upstream of ldhB. The biochemical and kinetic properties of this alternative lactate dehydrogenase (LDHB) were compared to those of the ldh-encoded enzyme (LDH), purified from the parental strain. In contrast to LDH, the affinity of LDHB for NADH and the activation constant for fructose 1,6-bisphosphate were strongly dependent on pH. The activation constant increased 700-fold, whereas the K(m) for NADH increased more than 10-fold, in the pH range 5.5-7.2. The two enzymes also exhibited different pH profiles for maximal activity. Moreover, inorganic phosphate acted as a strong activator of LDHB. The impact of replacing LDH by LDHB on the physiology of L. lactis was assessed by monitoring the evolution of the pools of glycolytic intermediates and cofactors during the metabolism of glucose by in vivo NMR. Structural analysis by comparative modeling of the two proteins showed that LDH has a slightly larger negative charge than LDHB and a greater concentration of positive charges at the interface between monomers. The calculated pH titration curves of the catalytic histidine residues explain why LDH maintains its activity at low pH as compared to LDHB, the histidines in LDH showing larger pH titration ranges.     

Follow-up assessment of patients with Pure Neural Leprosy in a reference center in Rio de Janeiro—Brazil

IntroductionPure Neural Leprosy (PNL) is a rare clinical form of leprosy in which patients do not present with the classical skin lesions but have a high burden of the disability associated with the disease. Clinical characteristics and follow up of patients in PNL are still poorly described in the literature.ObjectiveThis paper aims to describe the clinical, electrophysiological and histopathological characteristics of PNL patients, as well as their evolution after multidrug therapy (MDT).MethodsFifty-two PNL patients were selected. Clinical, nerve conduction studies (NCS), histopathological and anti-PGL-1serology were evaluated. Patients were also assessed monthly during the MDT. At the end of the MDT, all of the patients had a new neurological examination and 44 were submitted to another NCS.ResultsParesthesia was the complaint most frequently reported by patients, and in the neurological examination the most common pattern observed was impairment in sensory and motor examination and a mononeuropathy multiplex. Painful nerve enlargement, a classical symptom of leprosy neuropathy, was observed in a minority of patients and in the motor NCS axonal injuries, alone or in combination with demyelinating features, were the most commonly observed. 88% of the patients did not present any leprosy reaction during MDT. There was no statistically significant difference between the neurological examinations, nor the NCS pattern, performed before and after the MDT.DiscussionThe classical hallmarks of leprosy neuropathy are not always present in PNL making the diagnosis even more challenging. Nerve biopsy is an important tool for PNL diagnosis as it may guide therapeutic decisions. This paper highlights unique characteristics of PNL in the spectrum of leprosy in an attempt to facilitate the diagnosis and management of these patients.     

Double-antigen sandwich ELISA based on chimeric antigens for detection of antibodies to Trypanosoma cruzi in human sera

BackgroundEnzyme-linked immunosorbent assays (ELISA) are generally the chosen test for Chagas disease (CD) diagnosis; however, its performance depends on the antigen preparation adsorbed to the solid phase, which may lead to false-positive results and cross-reactions. The use of chimeric recombinant antigens can overcome this limitation. Four chimeric antigens from Trypanosoma cruzi (IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4) were developed and evaluated in phase I, II and III studies using indirect ELISA as diagnostic platform. However, peroxidase-labeled secondary anti-human IgG antibody, which is employed in indirect ELISAs, limits its use for the detection of species-specific and class-specific antibodies. To overcome this limitation, peroxidase-labeled antigens can be utilized, diagnosing both acute or chronic infection, in a species and immunoglobulin class-independent manner, through the use of a double-antigen sandwich ELISA (DAgS-ELISA). We aimed to evaluate and validate the diagnostic performance of the chimeric antigens IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4 in the DAgS-ELISA platform.Methodology/Principal findingsDAgS-ELISA was optimized by checkerboard titration. In phase I study, 207 positive and 205 negative samples were evaluated. Cross-reactivity to other infections was also assessed using 68 samples. The selected conditions for the tests utilized 25 ng of antigen per well and the conjugate diluted at 1:2,000 for all molecules. In the phase I study, the areas under the curve of IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4 were 98.7%, 99.5%, 98.6% and 98.8%, respectively. Among the positive samples, IBMP-8.1 antigen classified 53 (25.6%) as false negative, IBMP-8.2, 27 (13%), IBMP-8.3, 24 (11.6%) and IBMP-8.4, 43 (20.8%), giving sensitivities of 74.4%, 87%, 88.4% and 79.2%, respectively. The only antigen that did not reach 100% specificity was IBMP-8.3, with 96.6%. IBMP-8.3 was also the only molecule to show cross-reactivity with HTLV.Conclusions/SignificanceDAgS-ELISA is a promising tool for immunodiagnosis, and despite the high AUC values, the performance of this assay was different from the values obtained by our group when using these antigens in the indirect ELISA, for this reason, improvements are being considered to increase the sensitivity of the DAgS-ELISA.     

Arrest of oogenesis in the bug Rhodnius prolixus challenged with the fungus Aspergillus niger is mediated by immune response-derived PGE2

In this work we characterized the immune response of the insect Rhodnius prolixus to a direct injection into the hemocoel of the non-entomopathogenic fungus Aspergillus niger, and evaluated its consequences on host oogenesis. These animals were able to respond by mounting effective cellular and humoral responses to this fungus; these responses were shown, however, to have reproductive fitness costs, as the number of eggs laid per female was significantly reduced. The disturbance of egg formation during infectious process correlated with an elevation in the titer of hemolymph prostaglandin E₂ 48 h post-challenge. Administration of Zymosan A as an immunogenic non-infectious challenge produced similar effects on phenoloxidase and prophenoloxidase activities, oocyte development and prostaglandin E₂ titer, precluding the hypothesis of an effect mediated by fungal metabolites in animals challenged with fungus. Ovaries at 48 h post-challenge showed absence of vitellogenic ovarian follicles, and the in vivo administration of prostaglandin E₂ or its receptor agonist misoprostol, partially reproduced this phenotype. Together these data led us to hypothesize that immune-derived prostaglandin E₂ raised from the insect response to the fungal challenge is involved in disturbing follicle development, contributing to a reduction in host reproductive output and acting as a host-derived adaptive effector to infection.     

New imidazolidinic bioisosters: potential candidates for antischistosomal drugs

The emergence of strains of Schistosoma resistant to praziquantel has drawn attention to the search for new schistosomacide drugs. Imidazolidinic derivatives have performed outstandingly against adult S. mansoni worms when evaluated in vitro. The molecular modification of imidazolidine by way of bioisosteric replacement gives rise to variations in its biological response. This study verifies the potential of substituent groups in the derivatives (Z)3-benzyl-5-(2-fluoro-benzylidene)-imidazolidine-2,4-dione NE4, 3-benzyl-5-(4-chloro-arylazo)-4-thioxo-imidazolidin -2-ona PT5, 3-benzyl-5-(3-fluoro-benzylidene)-1-methyl-2-thioxo-imidazolidin-4-one JT53; 3-benzyl-1-methyl-5-(4-methyl-benzylidene)-2-thioxo-imidazolidin-4-one JT63; 3-benzyl-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo -imidazolidin-4-one JT68; 3-(4-chloro-benzyl)-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo-imidazolidin-4-one JT69; 3-(4-phenyl-benzyl)-1-methyl-5-(4-methoxi-benzylidene)-2-thioxo-imidazolidin-4-one JT72 by determining the viability in vitro of adult S. mansoni worms in the presence of these derivatives. The susceptibility of the worms obtained from mice and kept in culture in the presence of different concentrations was determined by way of schistosomacide kinetic, observed every 24 h over a period of eight days. The results show that the worms were more sensitive to the PT5 derivative at a concentration of 58 microM which killed 100% of the worms after 24 h of contact, also giving rise to alterations in the tegument surface of the worms with the formation of bubbles and peeling. These observations suggest a strong electronic contribution of the arylazo grouping in the biological response.     

Copper(II) complexes with (2-hydroxybenzyl-2-pyridylmethyl)amine–Hbpa: syntheses, characterization and crystal structures of the ligand and [Cu(II)(Hbpa)2](ClO4)2·2H2O

Copper(II) complexes were synthesized and characterized by means of elemental analysis, IR and visible spectroscopies, EPR and electrochemistry, as well as X-ray structure crystallography. The group consists of discrete mononuclear units with the general formula [Cu(II)(Hbpa)₂](A)₂·nH₂O, where Hbpa=(2-hydroxybenzyl-2-pyridylmethyl)amine and A=ClO₄ ⁻, n=2 (1), CH₃COO⁻, n=3 (2), NO₃ ⁻, n=2 (3) and SO₄ ²⁻, n=3 (4). The structures of the ligand Hbpa and complex 1 have been determined by X-ray crystallography. Complexes 1–4 have had their UV–Vis spectra measured in both MeCN and DMF. It was observed that the compounds interact with basic solvents, such that molecules coordinate to the metal in axial positions in which phenol oxygen atoms are coordinated in the protonated forms. The values were all less than 1000 M⁻¹ cm⁻¹. EPR measurements on powdered samples of 1–3 gave g/A values between 105 and 135 cm⁻¹, typical for square planar coordination environments. Complex 4·3H₂O exhibits a behaviour typical for tetrahedral coordination. The electrochemical behaviour for complexes 1 and 2 was studied showing irreversible redox waves for both compounds.     

Neurolysin Knockout Mice Generation and Initial Phenotype Characterization

The oligopeptidase neurolysin (EC 3.4.24.16; Nln) was first identified in rat brain synaptic membranes and shown to ubiquitously participate in the catabolism of bioactive peptides such as neurotensin and bradykinin. Recently, it was suggested that Nln reduction could improve insulin sensitivity. Here, we have shown that Nln KO mice have increased glucose tolerance, insulin sensitivity, and gluconeogenesis. KO mice have increased liver mRNA for several genes related to gluconeogenesis. Isotopic label semiquantitative peptidomic analysis suggests an increase in specific intracellular peptides in gastrocnemius and epididymal adipose tissue, which likely is involved with the increased glucose tolerance and insulin sensitivity in the KO mice. These results suggest the exciting new possibility that Nln is a key enzyme for energy metabolism and could be a novel therapeutic target to improve glucose uptake and insulin sensitivity.