Ações farmacológicas do acido tânico. III. Análise em outros modelos experimentais

Estudos de nosso laboratório surgerem que o ácido tânico (AT) exerce diversos efeitos "in vitro" ou "in vivo", podendo ser responsável por várias ações inespecíficas freqüentemente observadas com extratos brutos de plantas medicinais. O presente trabalho amplia estes estudos em outos modelos biológicos. A administração crônica ou aguda, por vida oral (v.o.), de AT em ratos não produziu alterações gástricas ou no processo inflamatório. Em ratos não-diabéticos observou-se modificações variáveis na glicemia de acordo com a metodologia empregada. O AT, cronicamente (v.o.), não interferiu na reprodução de fêmeas, embora constatou-se redução do número de filhotes de machos tratados. O AT (3mg/kg, v.o.) provocou aumento da diurese, porém doses mais elevadas não modificaram o volume urinário. Os testes hematológicos demonstraram que o AT possui efeito anticoagulante "in vitro", sem modificar a fragilidade de hemácias ou na homeastase sanguínea "in vivo". No músculo esquelético, o AT reduziu a resposta contrátil à acetilcolina, enquanto no músculo cardíaco (átrio esquerdo) observou-se efeito inotrópico positivo ou negativo. Estes resultados estendem os estudos anteriores e reforçam a sugestão de que parte significativa dos efeitos inespecíficos observados com extratos brutos de plantas medicinais podem estar relacionados com a presença de taninos nos mesmos.

Poderá o carrapato transmitir a lepra?: isolamento e cultura dum bacilo acido-álcool resistente de sedimento de "Amblyomma cajennense" capturado em leproso: 2ª nota

In this 2nd note upon the possibility of transmission of human leprosy by ticks, the A. relates his stepps to obtain the collaboration of his colleagues working in leprosaria in various States of Brazil, Argentina and Paraguay in such studies. Firstly the A. describes the positive results of examination of sediment of ticks, the cattle tick Boophilus microplus (Canestrini, 1888), received from Paraná (Leprosário São Roque) , which were put on active lepers, two of them sucking during 9 days and one during 7 days. Two out of three were killed for examination and were very strongly positive for acid-fast bacilli. A series of tubes of Loewenstein medium was smeared with the sediment of such ticks. Secondly the A. relates his personnal experiment, carried out in Rio de Janeiro, trying to infect normal ticks in lepers. The experiment with Boophilus microplus was negative and was twicely positive the experiment with Amblyomma cajennense Fabricius, 1794. The experiment is being in progress and will be continued in other places of Brazil. Finally, after being given the general characteristics of Boophilus microplus, the A. describes the non-chromogenic culture of a acid-fast bacillus isolated by him from sediment of ticks (Amblyomma cajennense) captured in lepers from Colônia Santa Isabel (Minas gerais), which parasitism was spontaneous. The first isolation was obtained in Loewenstein medium after 62 days incubation at 37°C. The culture is pure and the bacillus is permanent acid-fast. The plate1, in full color, represents this culture in its four generations. The colonies are pearl-white in color, dry, elevated and rough, developing slowly and beginning as white pinhead points scattered upon the surface of the medium. The culture is not yet rich enough to be inoculated into laboratory animals, which will be done when possible.

Poderá o carrapato transmitir a lepra?: mais quatro amostras de culturas de bacilos acido-alcool resistentes obtidas de carrapatos (2 de "Amblyomma cajennense"e 2 de "Boophilus microplus") infectados em leprosos do Paraná: 3ª nota

The AA. carried out experiments in the leprosarium São Roque, State of Paraná, South Brazil, to verify if the cattle tick Boophilus microplus could be experimentally infected in lepers, which was true. The AA. Tried also to be ascertained if Boophilus microplus and Amblyomma cajennense could change of hosts during their feedings which was true, both ticks continue feeding, the last species for many days, after being transferred from one to another leper. The junior A. describes in full their experiments and also a dermatites caused by tick bites. The senior A. brought to Rio de Janeiro most of the infected ticks for examination, which revealed a very high positivity. He smeared the sediments of lots of both species of ticks in Loewenstein medium and after a variable periode of incubation at 37° C. he obtained four new samples of cultures of acid-fast organisms, two from Amblyomma cajennense and two from Boophilus microplus. These cultures are being studied and will be inoculated into laboratory animals. The senior A. inoculated new batches of white rats with sediments of many ticks infected in lepers. Various hypotheses of both previous notes upon the subject now are verified facts. The A. is accumulating facts to draw the conclusions in the future. He also suggested the leprosy workers in the interior of the country to cooperate with him in such important studies, specially in the habitat of lepers in the rural zones of various States.

Ação do acido pteroílglutâmico sobre o peso e a fosfatase alcalina do rim

O APG ministrado subcutaneamente a camondongos normais em injeção unica após 24 hs produz um aumento do peso total dos rins e uma baixa da fosfatase alcalina destes orgãos. Os valores normais foram baseados em experiencias feitas em 54 camondongos e comparados com outros obtidos com 88 camondongos injetados com doses crescentes de APG (0,5~500mg/k). A fosfatase alcalina foi determinada por uma modificação do metodo colorimetro de King & Armstrong. A retenção e precipitação do APG nos estudosrenais parece ser responsavel pelo aumento de peso e a abaixa das fosfatase dos rins.

Distribuição temporal de perfis eletrofocéticos de Acido nucleico de rotavírus em fezes de crianças em Belém, Pará

Amostras de rotavírus provenientes de crianças habitantes na periferia de Belém, Pará, foram analisadas por eletroforese em gel de policrilamida (PAGE). As bandas correspondentes aos 11 segmentos de ARN foram detectadas em 46 (76,7%) das 60 amostras de rotavírus. Das amostras classificadas 5 (109%) foram relativas ao subgrupo I, 41 (89,1%) ao subgrupo II e, em 23,3%) não foi possível classificação face a ausência das bandas 10 e 11. As amostras de rotavírus sub-grupo II e codificadas como "1N2L" foram as mais freqüentes, ocorrendo em 30 (65,2%) das 46 classificadas.

A new approach for potential drug target discovery through in silico metabolic pathway analysis using Trypanosoma cruzi genome information

The current drug options for the treatment of chronic Chagas disease have not been sufficient and high hopes have been placed on the use of genomic data from the human parasite Trypanosoma cruzi to identify new drug targets and develop appropriate treatments for both acute and chronic Chagas disease. However, the lack of a complete assembly of the genomic sequence and the presence of many predicted proteins with unknown or unsure functions has hampered our complete view of the parasite's metabolic pathways. Moreover, pinpointing new drug targets has proven to be more complex than anticipated and has revealed large holes in our understanding of metabolic pathways and their integrated regulation, not only for this parasite, but for many other similar pathogens. Using an in silicocomparative study on pathway annotation and searching for analogous and specific enzymes, we have been able to predict a considerable number of additional enzymatic functions in T. cruzi. Here we focus on the energetic pathways, such as glycolysis, the pentose phosphate shunt, the Krebs cycle and lipid metabolism. We point out many enzymes that are analogous to those of the human host, which could be potential new therapeutic targets.

Megazol and its bioisostere 4H-1,2,4-triazole: comparing the trypanocidal, cytotoxic and genotoxic activities and their in vitro and in silico interactions with the Trypanosoma brucei nitroreductase enzyme

Megazol (7) is a 5-nitroimidazole that is highly active against Trypanosoma cruzi and Trypanosoma brucei, as well as drug-resistant forms of trypanosomiasis. Compound 7 is not used clinically due to its mutagenic and genotoxic properties, but has been largely used as a lead compound. Here, we compared the activity of 7 with its 4H-1,2,4-triazole bioisostere (8) in bloodstream forms of T. brucei and T. cruzi and evaluated their activation by T. brucei type I nitroreductase (TbNTR) enzyme. We also analysed the cytotoxic and genotoxic effects of these compounds in whole human blood using Comet and fluorescein diacetate/ethidium bromide assays. Although the only difference between 7 and 8 is the substitution of sulphur (in the thiadiazole in 7) for nitrogen (in the triazole in 8), the results indicated that 8 had poorer antiparasitic activity than 7 and was not genotoxic, whereas 7 presented this effect. The determination of Vmax indicated that although 8 was metabolised more rapidly than 7, it bounds to the TbNTR with better affinity, resulting in equivalent kcat/KM values. Docking assays of 7 and 8 performed within the active site of a homology model of the TbNTR indicating that 8 had greater affinity than 7.

Interferência do acido ascórbico na determinação de açúcares redutores pelo método de Lane e Eynon

Two studies, both set up as completely randomized design, in a 5x5 and 7x5 factorial schemes, evaluated the interference of 5 and 7 ascorbic acid concentrations and 5 glucose or 5 sucrose concentrations, respectively, on the determination of total and reducing sugars by Lane and Eynon method. The ascorbic acid reducing power (AARP) over the Fehling liquor interfered in the results of total and reducing sugars. On average the AARP was equivalent to 74.83 and 69.71% of the reducing power of glucose and of hydrolyzed sucrose, respectively. The ascorbic acid was stable in all study conditions.

ESTIRIL-LACTONAS DE Cryptocarya aschersoniana Mez. (Lauraceae Juss.) COM ATIVIDADE CONTRA Meloidogyne spp. E INTERAÇÃO IN SILICO COM PROVÁVEL FUMARASE DEMeloidogyne hapla

In a previous study, substances with nematicidal properties were detected in the bark of Cryptocarya aschersoniana. Continuing such study, the methanol extract from this plant underwent fractionation guided by in vitro assays with the plant-parasitic nematode Meloidogyne exigua. Two active compounds were isolated and identified by spectroscopic methods as (E)-6-styrylpyran-2-one and (R)-goniothalamin. The latter compound was also active againstMeloidogyne incognita. In silico studies carried out with (R)-goniothalamin and the enzyme fumarate hydratase, which was extracted from the genome of Meloidogyne hapla and modeled using computational methods, suggested that this substance acts against nematodes by binding to a cavity close to the active site of the enzyme.

In silico phylogenetic and virulence gene profile analyses of avian pathogenic Escherichia coli genome sequences

Avian pathogenic Escherichia coli (APEC) infections are responsible for significant losses in the poultry industry worldwide. A zoonotic risk has been attributed to APEC strains because they present similarities to extraintestinal pathogenic E. coli (ExPEC) associated with illness in humans, mainly urinary tract infections and neonatal meningitis. Here, we present in silico analyses with pathogenic E. coli genome sequences, including recently available APEC genomes. The phylogenetic tree, based on multi-locus sequence typing (MLST) of seven housekeeping genes, revealed high diversity in the allelic composition. Nevertheless, despite this diversity, the phylogenetic tree was able to cluster the different pathotypes together. An in silico virulence gene profile was also determined for each of these strains, through the presence or absence of 83 well-known virulence genes/traits described in pathogenic E. coli strains. The MLST phylogeny and the virulence gene profiles demonstrated a certain genetic similarity between Brazilian APEC strains, APEC isolated in the United States, UPEC (uropathogenic E. coli) and diarrheagenic strains isolated from humans. This correlation corroborates and reinforces the zoonotic potential hypothesis proposed to APEC.

Efeitos do acido giberélico (GA) e do cloreto de clorocolina (CCC) sobre o crescimento inicial de Brachiaria plantaginea (Link) Hitch

Com o objetivo de verificar os efeitos do ácido giberélico (GA) e do cloreto de clorocolina (CCC) sobre o crescimento e desenvolvimento inicial de Brachiaria plantaginea, instalou-se a presente pesquisa em local com alta infestação dessa espécie, utilizando-se dos seguintes tratamentos: CCC nas concentrações de 1000 e 2000 ppm, GA na de 50 e 100 ppm e uma testemunha sem aplicação dos fitoreguladores. Na época de aplicação dos produtos as plantas apresentavam, em média, sete folhas e idade em torno de 25 dias. Os parâmetros avaliados foram altura do dossel, altura média das plantas, número médio de perfilhos por planta, biomassa seca da parte aérea total e por indivíduo. Os resultados foram avaliados 22 dias após a aplicação, quando se verificou que a biomassa total das plantas não foi alterada significativamente pelos tratamentos. Não ocorreram efeitos de doses e nem de interações entre fitoreguladores com dose em quaisquer dos parâmetros avaliados. Não se verificaram efeitos do CCC nos dados obtidos e todas as alterações ocorridas foram devidas à aplicação do GA que aumentou, significativamente, a altura de dossel e dos indivíduos de Brachiaria plantaginea e reduziu o perfilhamento da planta daninha.

In silico analysis identifies a C3HC4-RING finger domain of a putative E3 ubiquitin-protein ligase located at the C-terminus of a polyglutamine-containing protein

Almost identical polyglutamine-containing proteins with unknown structures have been found in human, mouse and rat genomes (GenBank AJ277365, AF525300, AY879229). We infer that an identical new gene (RING) finger domain of real interest is located in each C-terminal segment. A three-dimensional (3-D) model was generated by remote homology modeling and the functional implications are discussed. The model consists of 65 residues from terminal position 707 to 772 of the human protein with a total length of 796 residues. The 3-D model predicts a ubiquitin-protein ligase (E3) as a binding site for ubiquitin-conjugating enzyme (E2). Both enzymes are part of the ubiquitin pathway to label unwanted proteins for subsequent enzymatic degradation. The molecular contact specificities are suggested for both the substrate recognition and the residues at the possible E2-binding surface. The predicted structure, of a ubiquitin-protein ligase (E3, enzyme class number 6.3.2.19, CATH code 3.30.40.10.4) may contribute to explain the process of ubiquitination. The 3-D model supports the idea of a C3HC4-RING finger with a partially new pattern. The putative E2-binding site is formed by a shallow hydrophobic groove on the surface adjacent to the helix and one zinc finger (L722, C739, P740, P741, R744). Solvent-exposed hydrophobic amino acids lie around both zinc fingers (I717, L722, F738, or P765, L766, V767, V733, P734). The 3-D structure was deposited in the protein databank theoretical model repository (2B9G, RCSB Protein Data Bank, NJ).