Efeitos da intoxicação etanólica durante a gestação e a lactação sobre o citoesqueleto de células neurais do hipocampo de ratos em desenvolvimento

O consumo de bebidas alcoólicas durante a gestação e lactação pode provocar uma série de efeitos adversos no feto. Por exemplo, a síndrome alcoólica fetal (SAF) causada pelo consumo de bebidas alcoólicas durante a gestação e é caracterizada por déficits de crescimento, dismorfia facial e evidências de anormalidades no sistema nervoso central (SNC). No presente estudo, nós investigamos os efeitos da exposição ao etanol administrado cronicamente em ratas durante a gestação e lactação sobre a homeostase do citoesqueleto de neurônios e astrócitos das progenitoras, no final da lactação, e da prole aos 9 e aos 21 dias de idade. Nossos resultados mostraram que os filhotes de ratas expostas ao etanol durante a gestação e lactação apresentaram, aos 21 dias de idade no hipocampo, um aumento na fosforilação das subunidades de baixo e médio peso molecular dos neurofilamentos (NF-L e NF-M) e da proteína glial fibrilar ácida (GFAP) de neurônios e astrócitos, respectivamente. Este efeito foi mediado pela proteína quinase ativada por sinal extracelular (ERK1/2) que pertence à família das proteínas quinases ativadas por mitógenos (MAPK). No entanto, esse mesmo efeito não ocorreu no córtex e hipocampo dos filhotes dessa idade. Nas progenitoras, no final do período de amamentação, e na prole aos 9 dias pós-natal não houve uma alteração na homeostase dos filamentos intermediários (FIs) do córtex, hipocampo e cerebelo. Esses dados reforçam a idéia que algumas regiões cerebrais são mais susceptíveis aos efeitos danosos do álcool e, também, que há uma janela de vulnerabilidade para esses danos. Sabendo-se que as crianças com SAF possuem déficits de aprendizado e memória e que o hipocampo está relacionado com essas funções, nossos resultados sugerem que uma alteração no citoesqueleto pode contribuir com os danos hipocampais relacionados à SAF.Maternal drinking during pregnancy and lactation can cause a number of adverse effects on the fetus. For example, the fetal alcohol syndrome (FAS) caused by prenatal exposure to alcohol is characterized by growth deficiency, facial dysmorphology and central nervous system (CNS) disorders. In the present study we investigated the effects of exposure to alcohol chronically administered to rats during pregnancy and lactation on the homeostasis of the cytoskeleton of neurons and astrocytes from dams at the end of lactation, and the offspring at 9 and at 21 days postpartum. Results showed that exposure to ethanol during pregnancy and lactation lead to increased phosphorylation of low and medium molecular weight neurofilament subunits (NF-L and NF-M) and of glial fibrillary acidic protein (GFAP) in astrocytes and neurons in the hippocampus of 21-day-old pups. This effect was mediated by extracellular signal regulated protein kinases (ERK1/2) which belongs to the family of mitogen-activated protein kinases (MAPK). However, this effect was not observed in the cerebral cortex and hippocampus of these animals. In dams at the end of the nursing period, and in 9-day-old pups the homeostasis of the intermediate filaments (IFs) of the cerebral cortex, hippocampus and cerebellum was not altered. These data reinforce the idea that some brain regions are more susceptible to the harmful effects of alcohol and reinforces the window of vulnerability of the hippocampus of immature brain. The children with FAS have deficits in learning and memory and the hippocampus is related to these functions, therefore it is feasible that an disruption of the homeostasis of the cytoskeleton can contribute to hippocampal damage related to ethanol exposure during pregnancy and lactation

Associação entre o ácido valpróico e o fator de crescimento de fibroblastos em matrizes produzidas por eletrofiação coaxial no tratamento da lesão da medula espinal em ratos

Diversos estudos têm sido realizados em busca de tratamentos para a lesão da medula espinal (LME) e o uso de estratégias da medicina regenerativa mostra-se promissor para promover o reparo no local da lesão. Os scaffolds de microfibras, produzidos por eletrofiação coaxial podem fornecer uma ponte para conectar as áreas de tecidos lesados na LME e desempenhar papéis ativos quando associados a moléculas bioativas. O fator de crescimento de fibroblastos 2 (FGF-2) e o ácido valpróico (VPA) têm sido descritos na literatura como importantes agentes que promovem neuroproteção e neuroregeneração. No presente trabalho, dois tipos de scaffolds foram produzidos pela técnica de eletrofiação coaxial, um deles contendo FGF-2 e o outro contendo VPA, no interior das microfibras. O potencial biológico desses biomaterias foi analisado em testes in vivo e in vitro. As fibras foram caracterizadas por microscopia eletrônica de varredura, de transmissão e confocal, bem como pela medida do ângulo de contato e das propriedades mecânicas. Além disso, estudos in vitro foram realizados para avaliar a liberação dessas substâncias dos scaffolds. A bioatividade do FGF-2 e do VPA foi analisada através de testes com células PC12, uma linhagem celular derivada de feocromocitomas de ratos geralmente utilizadas para estudos de scaffolds que visam a regeneração neural. As microfibras foram implantadas em um modelo de LME por hemisecção em ratos e, posteriormente, foram realizadas análises da recuperação motora, histologia e a quantificação da expressão de marcadores neurais. Os scaffolds produzidos por eletrofiação coaxial apresentaram microfibras uniformes com estrutura núcleo-casca e características morfológicas e mecânicas compatíveis para aplicação na LME. Os testes de liberação indicaram uma liberação rápida das duas substâncias nas primeiras oito horas de incubação e o FGF-2 foi detectado no meio por pelo menos 30 dias. As fibras coaxiais contendo tanto FGF como VPA suportaram a adesão, viabilidade e proliferação das células PC12. Além disso, o FGF-2 liberado induziu a diferenciação desse tipo celular. Enquanto o VPA provocou a redução da viabilidade dessas células como já descrito na literatura. A análise histológica do tecido da medula demonstrou que os scaffolds implantados in vivo foram integrados ao local da lesão. Os scaffolds com FGF-2 promoveram melhora locomotora dos animais aos 28 dias após a lesão e também reduziram a expressão de GFAP no local da lesão, indicando diminuição da cicatriz glial. Esses resultados indicam o excelente potencial dos scaffolds produzidos para o tratamento da LME.Several studies have been performed in search of treatments for spinal cord injury (SCI) and the use of regenerative medicine strategies is promising for promoting repair at the site of injury. Microfiber scaffolds, producing by coaxial electrospinning, can provide a bridge to connect the injured tissue areas in the SCI and play active roles when associated with bioactive molecules. The basic fibroblast growth factor (FGF-2) and valproic acid (VPA) have been described in the literature as important agents that promote neuroprotection and neuroregeneration. In this work, two types of biomaterials were produced by the coaxial electrospinning technique, one of them containing FGF-2 and the other containing VPA inside the microfibers. The biological potential of these scaffolds was analyzed using in vitro and in vivo tests. The fibers were characterized by scanning electron microscopy, transmission electron microscopy, laser confocal scanning microscopy, water contact angle and mechanical properties. In vitro studies were conducted to evaluate the release of these substances from the scaffolds . The bioactivity of FGF-2 and VPA was analyzed by tests with PC12 cells, a cell line derived from pheochromocytomas of rats commonly used for studies of scaffolds when the aim is neural regeneration. The microfibers were implanted in a hemisection SCI rat model and after 6 weeks the behavioral and histological analyses were performed; the expression of neural markers was quantified. The scaffolds produced by coaxial electrospinning presented uniform microfibers with core-shell structure and compatible morphological and mechanical characteristics for application in the SCI. Release tests indicated a rapid release of the two substances within the first hours of incubation and the FGF-2 was detected in the medium for at least 30 days. Coaxial fibers containing both FGF and VPA supported adhesion, viability and proliferation of PC12 cells. In addition, FGF-2 released by the fibers showed that its bioactivity was inducing the differentiation of this cell type, while VPA caused the reduction of PC12 cell viability, as already described in the literature. Histological analysis of the spinal cord tissue demonstrated that scaffolds implanted in vivo were integrated at the lesion site. PLGA and FGF- 2/PLGA scaffolds promoted locomotor improvement at 28 days post-injury and also reduced GFAP expression at the site of the lesion, indicating a decrease in glial scarring. These results indicate the excellent potential of the scaffolds produced for the treatment of SCI

Cacao breeding in Bahia, Brazil - strategies and results

Cacao was introduced in Bahia in 1756, becoming later the largest producer state in the country. In order to supportthe planting of cacao in the region, a breeding program was established by CEPEC at the beginning of the 1970s. For a long time,the program consisted in testing new hybrids (full-sibs) and releasing a mixture of the best ones to farmers. Lately, particularly afterthe witches´ broom arrival in the region, in 1989, recurrent breeding strategies were implemented, aiming mainly the developmentof clones. From 1993 to 2010, more than 500 progenies, accumulating 30 thousand trees, were developed by crossing many parentswith resistance to witches´ broom, high yield and other traits. In this period, more than 500 clones were put in trials and 39 clonesand 3 hybrids were released to farmers. In this paper the strategies and results achieved by the program are reviewed. Overall theprogram has good interface with pathology and genomic programs

VPA/PLGA microfibers produced by coaxial electrospinning for the treatment of central nervous system injury

The central nervous system shows limited regenerative capacity after injury. Spinal cord injury (SCI) is a devastating traumatic injury resulting in loss of sensory, motor, and autonomic function distal from the level of injury. An appropriate combination of biomaterials and bioactive substances is currently thought to be a promising approach to treat this condition. Systemic administration of valproic acid (VPA) has been previously shown to promote functional recovery in animal models of SCI. In this study, VPA was encapsulated in poly(lactic-co-glycolic acid) (PLGA) microfibers by the coaxial electrospinning technique. Fibers showed continuous and cylindrical morphology, randomly oriented fibers, and compatible morphological and mechanical characteristics for application in SCI. Drug-release analysis indicated a rapid release of VPA during the first day of the in vitro test. The coaxial fibers containing VPA supported adhesion, viability, and proliferation of PC12 cells. In addition, the VPA/PLGA microfibers induced the reduction of PC12 cell viability, as has already been described in the literature. The biomaterials were implanted in rats after SCI. The groups that received the implants did not show increased functional recovery or tissue regeneration compared to the control. These results indicated the cytocompatibility of the VPA/PLGA core-shell microfibers and that it may be a promising approach to treat SCI when combined with other strategies

Exposure of young rats to diphenyl ditelluride during lactation affects the homeostasis of the cytoskeleton in neural cells from striatum and cerebellum

AbstractIn the present report we examined the effect of maternal exposure to diphenyl ditelluride (PhTe)2 (0.01mg/kg body weight) during the first 14 days of lactational period on the activity of some protein kinases targeting the cytoskeleton of striatum and cerebellum of their offspring. We analyzed the phosphorylating system associated with glial fibrillary acidic protein (GFAP), and neurofilament of low, medium and high molecular weight (NF-L, NF-M and NF-H, respectively) of pups on PND 15, 21, 30 and 45. We found that (PhTe)2 induced hyperphosphorylation of all the proteins studied on PND 15 and 21, recovering control values on PND 30 and 45. The immunocontent of GFAP, NF-L, NF-M and NF-H in the cerebellum of 15-day-old pups was increased. Western blot assays showed activation/phosphorylation of Erk1/2 on PND 21 and activation/phosphorylation of JNK on PND 15. Otherwise, p38MAPK was not activated in the striatum of (PhTe)2 exposed pups. On the other hand, the cerebellum of pups exposed to (PhTe)2 presented activated/phosphorylated Erk1/2 on PND 15 and 21 as well as activated/phosphorylated p38MAPK on PND 21, while JNK was not activated. Western blot assays showed that both in the striatum and in the cerebellum of (PhTe)2 exposed pups, the immunocontent of the catalytic subunit of PKA (PKAcα) was increased on PND 15. Western blot showed that the phosphorylation level of NF-L Ser55 and NF-M/NF-H KSP repeats was increased in the striatum and cerebellum of both 15- and 21-day-old pups exposed to (PhTe)2. Diphenyl diselenide (PhSe)2, the selenium analog of (PhTe)2, prevented (PhTe)2-induced hyperphosphorylation of striatal intermediate filament (IF) proteins but it failed to prevent the action of (PhTe)2 in cerebellum. Western blot assay showed that the (PhSe)2 prevented activation/phosphorylation of Erk1/2, JNK and PKAcα but did not prevent the stimulatory effect of (PhTe)2 on p38MAPK in cerebellum at PND 21. In conclusion, this study demonstrated that dam exposure to low doses of (PhTe)2 can alter cellular signaling targeting the cytoskeleton of striatum and cerebellum in the offspring in a spatiotemporal manner, which can be related to the neurotoxic effects of (PhTe)2

Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

Unidad de excelencia María de Maeztu CEX2019-000940-MAim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types