Impact of protozoan cell death on parasite-host interactions and pathogenesis

PCD in protozoan parasites has emerged as a fascinating field of parasite biology. This not only relates to the underlying mechanisms and their evolutionary implications but also to the impact on the parasite-host interactions within mammalian hosts and arthropod vectors. During recent years, common functions of apoptosis and autophagy in protozoa and during parasitic infections have emerged. Here, we review how distinct cell death pathways in Trypanosoma, Leishmania, Plasmodium or Toxoplasma may contribute to regulation of parasite cell densities in vectors and mammalian hosts, to differentiation of parasites, to stress responses, and to modulation of the host immunity. The examples provided indicate crucial roles of PCD in parasite biology. The existence of PCD pathways in these organisms and the identification as being critical for parasite biology and parasite-host interactions could serve as a basis for developing new anti-parasitic drugs that take advantage of these pathways

Neuronal nitric oxide synthase is heterogeneously distributed in equine myofibers and highly expressed in endurance trained horses

Mammalian skeletal muscle expresses splice variants of neuronal nitric oxide synthase (nNOS). Skeletal muscles have a metabolically heterogeneous population of myofibers, and fiber composition in equine skeletal muscle is correlated with athletic ability in endurance events. In this study, we investigated whether nNOS expression in equine skeletal muscle is related to fiber type and endurance training. Biopsy samples obtained from the gluteus medius of sedentary- (SH) and endurance-trained (TH) horses were examined for the electrophoretic mobility of myosin heavy chain (MHC) and NOS activity. Serial tissue cross-sections were stained for myosin ATPase and nicotinamide adenine dinucleotide (NADH) reductase, and also immunostained for nNOS. The gluteus medius of TH had higher levels of nNOS expression and activity when compared to muscle from SH. In SH, nNOS was restricted to the subsarcolemmal area while in TH nNOS was also present at cytoplasmic sites. A splice variant of nNOS was heterogeneously distributed among the different myofibers, its expression being higher in fast-oxidative-glycolytic type IIA fibers than in fast-glycolytic type IIX fibers and absent in slow-twitch type I fibers. Trained horses had a significantly higher relative content of type IIA fibers, a greater oxidative capacity, and a lower percentage of type IIX fibers when compared with SH. The differences in muscle fiber typing between the 2 groups of horses reflected alterations that probably resulted from the endurance-training program. Overall, these results show that nNOS is differentially expressed and localized in the gluteus medius according to the fiber type and the athletic conditioning of the horses.691465

Effects of Anabolic Steroids and High-Intensity Aerobic Exercise on Skeletal Muscle of Transgenic Mice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)In an attempt to shorten recovery time and improve performance, strength and endurance athletes occasionally turn to the illicit use of anabolic-androgenic steroids (AAS). This study evaluated the effects of AAS treatment on the muscle mass and phenotypic characteristics of transgenic mice subjected to a high-intensity, aerobic training program (5d/wk for 6 weeks). The transgenic mice (CETP+/-LDLr-/+) were engineered to exhibit a lipid profile closer to humans. Animals were divided into groups of sedentary (Sed) and/or training (Ex) mice (each treated orally with AAS or gum arabic/vehicle: Sed-C, Sed-M, ex-C, ex-M). The effects of AAS (mesterolone: M) on specific phenotypic adaptations (muscle wet weight, cross-sectional area, and fiber type composition) in three hindlimb muscles (soleus: SOL, tibialis anterior: TA and gastrocnemius: GAS) were assessed. In order to detect subtle changes in fiber type profile, the entire range of fiber types (I, IC, IIAC, IIA, IIAD, IID, IIDB, IIB) was delineated using mATPase histochemistry. Body weight gain occurred throughout the study for all groups. However, the body weight gain was significantly minimized with exercise. This effect was blunted with mesterolone treatment. Both AAS treatment (Sed-M) and high-intensity, aerobic training (ex-C) increased the wet weights of all three muscles and induced differential hypertrophy of pure and hybrid fibers. Combination of AAS and training (ex-M) resulted in enhanced hypertrophy. In the SOL, mesterolone treatment (Sed-M and ex-M) caused dramatic increases in the percentages of fiber types IC, IIAC, IIAD, IID, with concomitant decrease in IIA, but had minimal impact on fiber type percentages in the predominantly fast muscles. Overall, the AAS-induced differential adaptive changes amounted to significant fiber type transformations in the fast-to-slow direction in SOL. AAS treatment had a significant effect on muscle weights and fiber type composition in SOL, TA and GAS which was even maximized in animals subjected to metabolically high-intensity aerobic exercise.811Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [Proc. 04/13767-9]CNPq [Proc. 522131/95-6]FAPESP [04/13768-5

Manejo diversificado del bosque: aprovechamiento de bienes y servicios de la biodiversidad del bosque neotropical

2 ilus. 2 tab. 29 ref

Fiber Type Composition of the Sternomastoid and Diaphragm Muscles of Dystrophin-Deficient mdx Mice

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The muscle fiber phenotype is mainly determined by motoneuron innervation and changes in neuromuscular interaction alter the muscle fiber type. In dystrophin-deficient mdx mice, changes in the molecular assembly of the neuromuscular junction and in nerve terminal sprouting occur in the sternomastoid (STN) muscle during early stages of the disease. In this study, we were interested to see whether early changes in neuromuscular assembly are correlated with alterations in fiber type in dystrophic STN at 2 months of age. A predominance of hybrid fast myo-fibers (about 52% type IIDB) was observed in control (C57B1/10) STN. In mdx muscle, the lack of dystrophin did not change this profile (about 54% hybrid type IIDB). Pure fast type HD fibers predominated in normal and dystrophic diaphragm (DIA; about 39% in control and 30% in mdx muscle) and a population of slow Type I fibers was also present (about 10% in control and 13% in mdx muscle). In conclusion, early changes in neuromuscular assembly do not affect the fiber type composition of dystrophic STN. In contrast to the pure fast fibers of the more affected DIA, the hybrid phenotype of the STN may permit dynamic adaptations during progression of the disease. Anat Rec, 293:1722-1728, 2010. (C) 2010 Wiley-Liss, Inc.2931017221728Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [04/15526-9, 07/50189-1, 08/58491-1, 08/50731-3]CNPq [302006/09-5, 301386/07-2

Impact of protozoan cell death on parasite-host interactions and pathogenesis

Abstract PCD in protozoan parasites has emerged as a fascinating field of parasite biology. This not only relates to the underlying mechanisms and their evolutionary implications but also to the impact on the parasite-host interactions within mammalian hosts and arthropod vectors. During recent years, common functions of apoptosis and autophagy in protozoa and during parasitic infections have emerged. Here, we review how distinct cell death pathways in Trypanosoma, Leishmania, Plasmodium or Toxoplasma may contribute to regulation of parasite cell densities in vectors and mammalian hosts, to differentiation of parasites, to stress responses, and to modulation of the host immunity. The examples provided indicate crucial roles of PCD in parasite biology. The existence of PCD pathways in these organisms and the identification as being critical for parasite biology and parasite-host interactions could serve as a basis for developing new anti-parasitic drugs that take advantage of these pathways.</p

Lineamientos para la planificaci?n del Bosque Modelo Reventaz?n,Costa Rica

Ilus. 1 tab. 22 ref.Este estudio tiene como prop?sito aportar lineamientos para la planificaci?n del Bosque Modelo Reventaz?n (BMR), en la cuenca del r?o Reventaz?n, Costa Rica. Se identificaron estrategias y mecanismos para facilitar la participaci?n de actores, detectar los principales problemas, potencialidades y las principales tendencias de cambio de los recursos naturales a largo plazo, definir los objetivos y la priorizaci?n de acciones del BMR. De la propuesta se resalta la importanc ia de la educaci?n, tema que sobresali? en varias etapas del estudio y debe pasar a ser uno de los pilares de la iniciativa del BMR, as? como la participaci?n de la sociedad. The present study aimed at developing planning guidelines for the establishment of the Reventaz?n Model Forest (RMF) in the Reventaz?n River watershed, Costa Rica. Strategies and mechanisms for the stakeholder?s participation were identified as well as the main problems and potentialities, the main trends of change for natural resources in the long term, and the objectives and actions prioritization for the RMF. During the process, education stood out as a leading issue, therefore it should become a priority of the RMF initiative, as well as mechanisms to foster the stakeholder participation

Uso de productos forestales en la Reserva Ind?gena Cab?car de Alto Chirrip?, Costa Rica

Ilus. 1 tab.El presente trabajo aporta una aproximaci?n al conocimiento de los productos forestales y sus usos por parte de los ind?genas cab?cares de cinco comunidades: Nimar?, Quetzal, Xuquebachari, Simiri?ac y Sharabata, describiendo las oportunidades y limitaciones para la conservaci?n, producci?n y comercializaci?n de los recursos del bosque. Por otro lado, la carencia de infraesructura b?sica como carreteras y medios de comunicaci?n se constituy? en la principal limitante identificada para el transporte y comercio de los productos provenientes de las comunidades ind?genas. This research is a contribution to the knowledge of forest products and there uses by five Cabecar comunities: Nimar?, Quetzal, Xuquebachari, Simiri?ac y Sharabata, describing the opportunities and limitations for the commercialization of forest resources. Nowadays, the deficiency of basic infrastructure such as roads and media constitute the main limitation for transport and commercialization of products of indigenous comunities