Linalool, a Piper aduncum essential oil component, has selective activity against Trypanosoma cruzi trypomastigote forms at 4°C

BACKGROUND Recent studies showed that essential oils from different pepper species (Piper spp.) have promising leishmanicidal and trypanocidal activities. OBJECTIVES In search for natural compounds against Trypanosoma cruzi, different forms of the parasite were incubated for 24 h at 28ºC or 4ºC with Piper aduncum essential oil (PaEO) or its main constituents linalool and nerolidol. METHODS PaEO chemical composition was obtained by GC-MS. Drug activity assays were based on cell counting, MTT data or infection index values. The effect of PaEO on the T. cruzi cell cycle and mitochondrial membrane potential was evaluated by flow cytometry. FINDINGS PaEO was effective against cell-derived (IC50/24 h: 2.8 μg/mL) and metacyclic (IC50/24 h: 12.1 μg/mL) trypomastigotes, as well as intracellular amastigotes (IC50/24 h: 9 μg/mL). At 4ºC - the temperature of red blood cells (RBCs) storage in blood banks - cell-derived trypomastigotes were more sensitive to PaEO (IC50/24 h = 3.8 μg/mL) than to gentian violet (IC50/24 h = 24.7 mg/mL). Cytotoxicity assays using Vero cells (37ºC) and RBCs (4ºC) showed that PaEO has increased selectivity for cell-derived trypomastigotes. Flow cytometry analysis showed that PaEO does not affect the cell cycle of T. cruzi epimastigotes, but decreases their mitochondrial membrane potential. GC-MS data identified nerolidol and linalool as major components of PaEO, and linalool had trypanocidal effect (IC50/24 h: 306 ng/mL) at 4ºC. MAIN CONCLUSION The trypanocidal effect of PaEO is likely due to the presence of linalool, which may represent an interesting candidate for use in the treatment of potentially contaminated RBCs bags at low temperature.

Agentes de limpeza terceirizados: entre o ressentimento e o reconhecimento / Outsourced cleaning workers: between resentment and the recognition

Resumo Objetivo: analisar a percepção sobre a atividade de trabalho dos agentes de limpeza terceirizados de uma faculdade pública e determinar seu índice de capacidade para o trabalho. Métodos: foram utilizadas três ferramentas - Análise Coletiva do Trabalho (ACT); Questionário Sociodemográfico de trabalho e de estilo de vida (QSD) e o Índice de Capacidade para o Trabalho (ICT). Resultados/discussão: das 22 agentes de limpeza, seis apresentaram ICT Baixo e Mode­rado, o que as coloca em posição de vulnerabilidade. Para além das demandas físicas de trabalho, as queixas das agentes de limpeza se concentraram nos riscos psicossociais, especialmente relacionados ao estresse e ao assédio moral. As trabalhadoras acreditam no valor de suas atividades, mas manifestaram ressentimento pela falta de reconhecimento por parte dos gestores e usuários da instituição. Conclusão: Fica evidente a necessidade de intervir nesse contexto para a manutenção da capacidade de trabalho e das condições para viver bem destes agentes de limpeza terceirizados.

Abstract Objective: to analyze the perception of the outsourced cleaning workers from a public university on their work activity and to determine their work ability index. Method: three tools were used - Collective Work Analysis; a social-demographic, occupational and lifestyle questionnaire; and Work Ability Index (WAI). Results/discussion: from the 22 cleaning workers, six presented low and moderated WAI, which shows that they are in a vulnerable position. Besides the physical demands, the workers’ complaints were about psychosocial risks, specially related to stress and workplace bullying. Discussion: The cleaning workers believe in the quality value that their activities add to the university and expressed resentment by the lack of recognition from the managers and users of the institution. It is clear that the university needs to intervene in those work conditions so that workers can maintain their work capacity and well being.

Biological activity of the essential oils from Cinnamodendron dinisii and Siparuna guianensis

This study had analyzed the antibacterial, antifungal and trypanocidal activity of the essential oils from Cinnamodendron dinisii Schwacke (Canellaceae) and Siparuna guianensis Aublet (Siparunaceae). The essential oils were obtained from fresh leaves by hydrodistillation, using a modified Clevenger apparatus. Chemical analysis by gas-liquid chromatography coupled to mass spectrometry (GC-MS) showed that these essential oils are rich in monoterpene and sesquiterpene hydrocarbons. Activity against the pathogenic bacteria Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella choleraesuis and Staphylococcus aureus was evaluated with the agar cavity diffusion method, while activity on the filamentous fungi Aspergillus flavus, Aspergillus niger, Aspergillus carbonarius and Penicillium commune was evaluated by the disk diffusion technique. Trypanocidal activity was tested against Trypanosoma cruzi epimastigotes, using the Tetrazolium salt (MTT) colorimetric assay. Both essential oils exhibited low inhibitory effect towards bacteria, showing high MIC values (125–500 μg mL−1), with Gram positive bacteria being more susceptible. Better inhibitory effect was obtained for the evaluated fungi, with lower MIC values (7.81–250 μg mL−1), being A. flavus the most susceptible species. Both essential oils presented low trypanocidal activity, with IC50/24 h values of 209.30 μg mL−1 for S. guianensis and 282.93 μg mL−1 for C. dinisii. Thus, the high values observed for the MIC of evaluated bacteria and for IC50/24 h of T. cruzi, suggest that the essential oils have a low inhibitory activity against these microorganisms. In addition, the low MIC values observed for the tested fungi species indicate good inhibitory activity on these microorganisms’s growth.

Actin expression in trypanosomatids (Euglenozoa: Kinetoplastea)

Heteroxenic and monoxenic trypanosomatids were screened for the presence of actin using a mouse polyclonal antibody produced against the entire sequence of the Trypanosoma cruzi actin gene, encoding a 41.9 kDa protein. Western blot analysis showed that this antibody reacted with a polypeptide of approximately 42 kDa in the whole-cell lysates of parasites targeting mammals (T. cruzi, Trypanosoma brucei and Leishmania major), insects (Angomonas deanei, Crithidia fasciculata, Herpetomonas samuelpessoai and Strigomonas culicis) and plants (Phytomonas serpens). A single polypeptide of approximately 42 kDa was detected in the whole-cell lysates of T. cruzi cultured epimastigotes, metacyclic trypomastigotes and amastigotes at similar protein expression levels. Confocal microscopy showed that actin was expressed throughout the cytoplasm of all the tested trypanosomatids. These data demonstrate that actin expression is widespread in trypanosomatids.

The zinc finger protein TcZFP2 binds target mRNAs enriched during Trypanosoma cruzi metacyclogenesis

Trypanosomes are parasitic protozoa in which gene expression is primarily controlled through the regulation of mRNA stability and translation. This post-transcriptional control is mediated by various families of RNA-binding proteins, including those with zinc finger CCCH motifs. CCCH zinc finger proteins have been shown to be essential to differentiation events in trypanosomatid parasites. Here, we functionally characterise TcZFP2 as a predicted post-transcriptional regulator of differentiation in Trypanosoma cruzi. This protein was detected in cell culture-derived amastigotes and trypomastigotes, but it was present in smaller amounts in metacyclic trypomastigote forms of T. cruzi. We use an optimised recombinant RNA immunopreciptation followed by microarray analysis assay to identify TcZFP2 target mRNAs. We further demonstrate that TcZFP2 binds an A-rich sequence in which the adenosine residue repeats are essential for high-affinity recognition. An analysis of the expression profiles of the genes encoding the TcZFP2-associated mRNAs throughout the parasite life cycle by microarray hybridisation showed that most of the associated mRNAs were upregulated in the metacyclic trypomastigote forms, also suggesting a role for TcZFP2 in metacyclic trypomastigote differentiation. Knockdown of the orthologous Trypanosoma brucei protein levels showed ZFP2 to be a positive regulator of specific target mRNA abundance.

Lanfrediella amphicirrus gen. nov. sp. nov. Nematotaeniidae (Cestoda: Cyclophyllidea), a tapeworm parasite of Rhinella marina (Linnaeus, 1758) (Amphibia: Bufonidae)

The family Nematotaeniidae, tapeworms commonly found in the small intestines of amphibians and reptiles, includes 27 recognised species distributed among four genera: Bitegmen Jones, Cylindrotaenia Jewell, Distoichometra Dickey and Nematotaenia Lühe. The taxonomy of these cestodes is poorly defined, due in part to the difficulties of observing many anatomical traits. This study presents and describes a new genus and species of nematotaeniid parasite found in cane toads (Rhinella marina) from eastern Brazilian Amazonia. The cestodes were collected during the necropsy of 20 hosts captured in the urban area of Belém, Pará. The specimens were fixed and processed for light microscopy, scanning electron microscopy (SEM) and three-dimensional (3D) reconstruction. Samples were also collected for molecular analyses. The specimens presented a cylindrical body, two testes and paruterine organs. However, they could not be allocated to any of the four existing nematotaeniid genera due to the presence of two each of dorsal compact medullary testes, cirri, cirrus pouches, genital pores, ovaries and vitelline glands per mature segment. Lanfrediella amphicirrus gen. nov. sp. nov. is the first nematotaeniid studied using Historesin analysis, SEM and 3D reconstruction, and it is the second taxon for which molecular data have been deposited in GenBank.

Gingko biloba leaves extract on growth and morphology of trypanosomatids / Efecto del extracto de las hojas de Gingko biloba en el crecimiento y la morfología de tripanosomátidos

Gingko biloba has been one of the most used medicinal plants all over the world in the past years. In this study, our group has studied the effect of a hydroethanolic extract from the aerial parts of this plant on the growth and morphological differentiation of trypanosomatids. Herpetomonas samuelpessoai and Herpetomonas sp were used in this study. The extract was obtained in a Soxhlet apparatus (50 oC, 2 hours). This extract was aseptically added to Roitman’s medium in different concentrations (4, 20, 40, 60, 80 and 100 mg/ml). The growth rate was determined using a Newbauer chamber to count numbers of cells after the extract inoculation (24 and 72 hours later). Smears stained by the Panotic method was used to determine the percentages of pro, para and opisthomastigote forms. The extract inhibited Herpetomonas sp growth in concentrations higher than 20 mg/ml. H. samuelpessoai has been inhibited in doses higher than 40 mg/ml. No morphological differentiation was observed in Herpetomonas sp cell. However, morphological differentiations could be noticed in H. samuelpessoai cell using doses higher than 40 mg/ml. These alterations are probably related to the cell division process, since cells with 3 or 4 nucleus were observed. Also, cytoplasmatic expansions, representing unsuccessful process of cell division were frequently found out. Further ultrastructural analysis using a transmission electron microscope showed cells with homogeneous nucleus or the absence of it. Protozoan protein profile was also analyzed. It was possible to notice changes in both trypanosomatids used in this study. H. samuelpessoai has shown over expression and accumulation of proteins which its degradation is essential to continue the cell differentiation. Also, it is possible to suggest that this extract acts through the modulation of the genetic expression and may be harmful to human cells if not purified.

Gingko biloba es una de las plantas medicinales más utilizadas en todo el mundo en los últimos años. En este estudio, nuestro grupo ha estudiado el efecto de un extracto hidroetanólico de la parte aérea de esta planta sobre el crecimiento y la diferenciación morfológica de tripanosomátidos. Herpetomonas samuelpessoai y Herpetomonas sp se utilizaron en este estudio. El extracto se obtuvo en un aparato Soxhlet (50° C/2 horas). Este extracto se agregó asépticamente a medio Roitman en diferentes concentraciones (4, 20, 40, 60, 80 y 100 mg /ml). La tasa de crecimiento se determinó utilizando una cámara de Newbauer para contar el número de células después de la inoculación de extracto (24 y 72 horas más tarde). Frotis teñidos por el método Panotic se utilizó para determinar los porcentajes de pro, para y las formas opistomastigota. El extracto inhibió el crecimiento Herpetomonas sp en concentraciones superiores a 20 mg /ml. H. samuelpessoai se ha inhibido en dosis superiores a 40 mg /ml. No se observó diferenciación morfológica en la celda Herpetomonas sp. Sin embargo, las diferenciaciones morfológicas se pudo observar en la celda H. samuelpessoai con dosis superiores a 40 mg /ml. Estas alteraciones son probablemente relacionado con el proceso de división celular, ya que las células con 3 o 4 núcleos se observaron. Además, las expansiones citoplasmáticas, lo que representa el proceso fallido de la división celular se encontraron con frecuencia hacia fuera. Un análisis más detallado ultraestructural usando microscopio electrónico de transmisión mostró células con núcleo homogéneo o la ausencia de ella. El perfil de proteínas por Protozoarios también se ha analizado. Fue posible notar cambios tanto en tripanosomátidos utilizados en este estudio. H. samuelpessoai ha demostrado a lo largo de expresión y la acumulación de proteínas que su degradación es esencial para continuar con la diferenciación celular. Además, es posible sugerir que este extracto...

In vitro effects of citral on Trypanosoma cruzi metacyclogenesis

Citral, the main constituent of lemongrass (Cymbopogon citratus) essential oil, was added to Trypanosoma cruzi cultures grown in TAU3AAG medium to observe the effect on the epimastigote-to-trypomastigote differentiation process (metacyclogenesis). Our results showed that citral (20 μg/mL) did not affect epimastigote viability or inhibit the differentiation process. Concentrations higher than 60 μg/mL, however, led to 100 percent cell death (both epimastigote and trypomastigote forms). Although epimastigotes incubated with 30 μg/mL citral were viable and able to adhere to the substrate, we observed around 50 percent inhibition in metacyclogenesis, with a calculated concentration that inhibited metacyclogenesis by 50 percent after 24 h (IC50/24 h) of about 31 μg/mL. Treatment with 30 μg/mL citral did not hinder epimastigote multiplication because epimastigote growth resumed when treated cells were transferred to a drug-free liver infusion tryptose culture medium. Metacyclogenesis was almost totally abolished at 40 μg/mL after 24 h of incubation. Furthermore, the metacyclic trypomastigotes obtained in vitro were similarly susceptible to citral, with an IC50/24 h, concentration that killed 50 percent of the cells after 24 h, of about 24.5 μg/mL. Therefore, citral appears to be a good candidate as an inhibitory drug for further studies analyzing the T. cruzi metacyclogenesis process.

Subcellular localization of an intracellular serine protease of 68 kDa in Leishmania (Leishmania) amazonensis promastigotes

Here we report the subcellular localization of an intracellular serine protease of 68 kDa in axenic promastigotes of Leishmania (Leishmania) amazonensis, using subcellular fractionation, enzymatic assays, immunoblotting, and immunocytochemistry. All fractions were evaluated by transmission electron microscopy and the serine protease activity was measured during the cell fractionation procedure using a-N-r-tosyl-L-arginine methyl ester (L-TAME) as substrate, phenylmethylsulphone fluoride (PMSF) and L-1-tosylamino-2-phenylethylchloromethylketone (TPCK) as specific inhibitors. The enzymatic activity was detected mainly in a membranous vesicular fraction (6.5-fold enrichment relative to the whole homogenate), but also in a crude plasma membrane fraction (2.0-fold). Analysis by SDS-PAGE gelatin under reducing conditions demonstrated that the major proteolytic activity was found in a 68 kDa protein in all fractions studied. A protein with identical molecular weight was also recognized in immunoblots by a polyclonal antibody against serine protease (anti-SP), with higher immunoreactivity in the vesicular fraction. Electron microscopic immunolocalization using the same polyclonal antibody showed the enzyme present at the cell surface, as well as in cytoplasmic membranous compartments of the parasite. Our findings indicate that the internal location of this serine protease in L. amazonensis is mainly restricted to the membranes of intracellular compartments resembling endocytic/exocytic elements.

Anopheles albitarsis embryogenesis: morphological identification of major events

Anopheles albitarsis embryogenesis was analyzed through confocal microscopy of clarified eggs. Using Drosophila melanogaster as reference system, the major morphogenetic events (blastoderm, gastrulation, germ band extension, germ band retraction, dorsal closure) were identified. The kinetics of early events is proportionally similar in both systems, but late movements (from germ band retraction on) progress slower in An. albitarsis. Major differences in An. albitarsis related to D. melanogaster were: (1) pole cells do not protrude from the blastoderm; (2) the mosquito embryo undergoes a 180º rotation movement, along its longitudinal axis; (3) the head remains individualized throughout embryogenesis; (4) extraembryonary membranes surround the whole embryo. A novel kind of malaria control is under development and is based on the use of genetically modified mosquitoes. Phenotypic analysis of the embryonic development of mutants will be imposed as part of the evaluation of effectiveness and risk of employment of this strategy in the field. In order to accomplish this, knowledge of the wild type embryo is a prerequisite. Morphological studies will also serve as basis for subsequent development biology approaches

Três novas espécies de tripanosomatídeos de insetos isolados em Alfenas, Minas Gerais, Brasil / Three new species of trypanosomatidae isolated in Alfenas, Minas Gerais, Brazil

Três novas espécies de tripanosomatídeos foram isoladas em Alfenas, MG, Brasil: Herpetomonas anglusteri sp. n., do intestino posterior de Liopygia ruficorins (Diptera: Sarcophagidae); Crithidia roitmani sp. e.e Crithidia de souzai sp. n., do intestino médio e o posterior de Ornidia obesa (Diptera: Syrphidae). O isolamento foi feito em meio complexo de roitmanmas os três isolados cresceram bem no meio definido do mesmo Autor. Os clones foram obtidos em ágar-sangue de carneiro, desfibrinado, em placas de Petri, a 28-C, por 2-7 dias. Um único clone de cada espécie foi utilizado neste trabalho. Dados morfológicos e morfométricos foram obtidos em câmara clara após coloraçäo dos flagelados. H. anglusteri cresceu em meio complexo tanto a 28 como a 37-C e, em meio definido, apenas a 28-C. Näo exige treonina e biotina para seu crescimento. C. roitmani apresenta tamanho médio maior que C. desouzai, näo cresce em água de coco e seu crescimento é mais lento comparativamente a C. desouzai, apesar de terem sido isoladas critídias exige hemina e adenina para seu crescimento. Alguns ácidos aminados e vitaminas componentes do meio definido utilizado no ensaio, também näo säo exigidos, o que sugere serem estes tripanosomatídeos portadores de endossimbiontes