Anti-plasmodial and anti-trypanosomal activity of synthetic naphtho[2,3-b]thiophen-4,9-quinones

Naphtho[2,3-b]thiophen-4,9-quinone and five derivatives were prepared using the Friedel-Crafts reaction and tandem-lithiation of aromatic diethylamides. These quinones were evaluated for their trypanocidal and anti-plasmodial activities by their effects on: (1) growth of epimastigote forms of Trypanosoma cruzi in vitro, (2) lysis of trypomastigote forms of T. cruzi in murine blood, (3) growth of Plasmodium falciparum in vitro, and (4) inhibition of the recombinant enzyme trypanothione reductase. The parent compound, naphtho[2,3-b]thiophen-4,9-quinone (3a), was among the most active quinone tested in vitro against P. falciparum at 0.2 μM. However, it was inactive against P. berghei-infected mice treated with 2.3 mmol/kg daily for 5 days. Most of the quinones prepared were active against T. cruzi epimastigotes in culture but exhibited weak activity at 4 °C against trypomastigotes in murine blood as well against the enzyme trypanothione reductase. Further structural modifications will be necessary to improve the in vivo activity of the naphthothiophenquinones.     

Isolation of Trypanosoma cruzi samples by xenodiagnosis and hemoculture from patients with chronic Chagas' disease

Fifty nine chronic chagasic patients were simultaneously submitted to xenodiagnosis and hemoculture for Trypanosoma cruzi samples isolations. The xenodiagnosis was done with 40 Panstrongylus megistus, Triatoma infestans and Dipetalogaster maximus nymphs, performing 120 triatomines. Groups of 10 insects per specie were dissecated and the intestinal content pooled and examined, after previous trituration and homogenization. The microscopically negative material was seed into LIT medium and examined after 20 days. Twenty nine patients were parasitologically proved, being 15 only by xenodiagnosis, 4 only by hemoculture and 10 by both methods. It was discussed the parasitological comprovation difficulties in chronic chagasic patients, the value of the simultaneous utilization of different triatomine species in xenodiagnosis and the hemoculture, in a favorable positive association to the sensitivity increase in the diagnosis' disease. The 49.2% of positivity obtained in this group, visualize approaches like clinic-therapeutic assay and or epidemiological (case-control) with the purpose to investigate a possible association with T. cruzi samples and different clinic forms in Chagas' disease.     

Natural infection of the anal glands of the opossum (Didelphis albiventris) by Trypanosoma cruzi in the municipality of Bambuí--MG, Brazil

Out of 87 opossums, Didelphis albiventris, captured in the Bambuí area (Minas Gerais State), 32 (36.7%) were found infected by Trypanosoma cruzi; the rates varied according to whether the specimens originated from sylvan, rural peridomiciliar or urban surroundings, being 34.9, 81.8 and 7.7 respectively. From 20 of the infected opossums the anal glands were repeatedly examined and found positive in only one (5%) specimen (GA 9), with 7 positive examinations out of 17 performed through an 18-months periods. Material from these glands produced patent parasitemia in opossums and sub-patent infections in mice. Isolates from the opossum GA 9, obtained through xenodiagnoses and hemocultures and from cultures of the infected anal glands fitted into zymodeme Z1.     

Comparative biological characterization of Berenice and Berenice-78 strains of Trypanosoma cruzi isolated from the same patient at different times

The Berenice-78 strain of T. cruzi is very different from the Berenice strain isolated 16 years earlier from the same patient. The authors verified its high infectivity and low virulence for C3H inbred mice that survived the acute phase of infection. In these animals, it was verified that the tropism of parasites was more accentuated for cardiac and skeletal musculature and the parasitaemic level progressively increased with successive blood passages with posterior stability. In relation to Berenice strain the same characteristics were observed as described by Brener, Chiari & Alvarenga (1974). The increase in its virulence for albino mice was again demonstrated. The authors discussed the possibility of reinfection of the patient called Berenice and the importance of knowledge about T. cruzi strains of low virulence for laboratory animals.     

Tissue culture response in various wild and cultivated Solanum germplasm accessions for exploitation in potato breeding

The response to different in vitro methods for use in potato breeding has been evaluated in 11 genotypes of 5 Solanum species, S. etuberosum, S. lycopersicoides, S. maglia, S. rickii, and S. tuberosum. Callus induction and growth, and shoot regeneration were strongly influenced by the genotype, explant source, and medium utilized. Furthermore, considerable differences among the 11 genotypes were found both in plating efficiency and shoot regeneration from protoplast culture. Some interesting correlations were found between different tissue culture responses, suggesting linkage and/or pleiotropic effect of genes. The potential application to potato breeding of the in vitro techniques analyzed is discussed.Abbreviations BA 6-benzylaminopurine - GA₃ gibberellic acid - NAA naphthaleneacetic acid - MS Murashige & Skoog (1962) - 2,4-d dichlorophenoxyacetic acid     

Detection of allergen specific immunoglobulins by microarrays coupled to microfluidics

Allergen microarrays are under development for a component‐resolved diagnosis of Type I (IgE‐mediated) allergies. Here we report an improved microarray coupled to microfluidics for the detection of allergen specific immunoglobulin E (IgE). The signal intensity for IgE detection in serum has been improved by using glass slides coated with a novel poly[DMA‐co‐NAS] brush copolymer which is able to immobilize allergens in their native conformation and by carrying out the incubation step in dynamic conditions. The assay, fully automated, was performed in a microcell, using a software‐controlled fluidic processor, to bring assay reagents on the surface of the array. Microfluidics turns the binding between serum immunoglobulins and immobilized allergens from a diffusion‐limited to a kinetic‐limited process by ensuring an efficient mixing of serum samples on the surface of the microarray. As a result of this, the binding of high affinity IgE antibodies is enhanced whereas that of low affinity IgG antibodies, which are present at higher concentration, is impaired paving the way to more accurate and sensitive results.