Tauroursodeoxycholic acid increases neural stem cell pool and neuronal conversion by regulating mitochondria-cell cycle retrograde signaling

The low survival and differentiation rates of stem cells after either transplantation or neural injury have been a major concern of stem cell-based therapy. Thus, further understanding long-term survival and differentiation of stem cells may uncover new targets for discovery and development of novel therapeutic approaches. We have previously described the impact of mitochondrial apoptosis-related events in modulating neural stem cell (NSC) fate. In addition, the endogenous bile acid, tauroursodeoxycholic acid (TUDCA) was shown to be neuroprotective in several animal models of neurodegenerative disorders by acting as an anti-apoptotic and anti-oxidant molecule at the mitochondrial level. Here, we hypothesize that TUDCA might also play a role on NSC fate decision. We found that TUDCA prevents mitochondrial apoptotic events typical of early-stage mouse NSC differentiation, preserves mitochondrial integrity and function, while enhancing self-renewal potential and accelerating cell cycle exit of NSCs. Interestingly, TUDCA prevention of mitochondrial alterations interfered with NSC differentiation potential by favoring neuronal rather than astroglial conversion. Finally, inhibition of mitochondrial reactive oxygen species (mtROS) scavenger and adenosine triphosphate (ATP) synthase revealed that the effect of TUDCA is dependent on mtROS and ATP regulation levels. Collectively, these data underline the importance of mitochondrial stress control of NSC fate decision and support a new role for TUDCA in this process.     

Artificial nest predation by brown howler monkeys (Alouatta guariba clamitans)

Howler monkeys (Alouatta spp.) have long been considered strongly vegetarian primates. Their occasional ingestion of invertebrates has largely been interpreted as unintentional. Recent observations of the consumption of bird eggs by Alouatta caraya living in small and resource-impoverished habitat patches in the state of Rio Grande do Sul (RS), Brazil help to confirm that such behavior by howler monkeys is at times intentional. We report the findings of an experimental study on artificial nest predation by free-ranging Alouatta guariba clamitans in RS and third-party unpublished observations of intentional feeding on animal matter by Alouatta arctoidea in Venezuela and Alouatta palliata in Mexico. A nest station composed of ten artificial nests baited daily with two quail eggs each was placed at six study sites. Each site was monitored from dawn to dusk during 10–12 consecutive days. Individuals (juvenile males and an adult female) from two of the six study groups inspected the nests and ate eggs once. Study subjects from these two groups were the only ones to be supplemented with food (basically fruit) by local inhabitants, a habit that may have decreased their level of neophobia and facilitated their visit to the artificial nests. We suggest that faunivory is an opportunistic and infrequent, but intentional howler monkey feeding behavior.     

Cell wall proteomics of sugarcane cell suspension cultures

The use of cell walls to produce cellulosic ethanol from sugarcane bagasse is a new challenge. A better knowledge of proteins involved in cell wall remodelling is essential to improve the saccharification processes. Cell suspension cultures were used for this first cell wall proteomics study of sugarcane. Proteins extracted from cell walls were identified using an adapted protocol. They were extracted using 0.2 M CaCl₂ and 2 M LiCl after purification of cell walls. The proteins were then identified by the innovative nanoACQUITY UPLC MS/MS technology and bioinformatics using the translated SUCEST EST cluster database of sugarcane. The experiments were reproduced three times. Since Sorghum bicolor is the closest plant with a fully sequenced genome, homologous proteins were searched for to complete the annotation of proteins, that is, prediction of subcellular localization and functional domains. Altogether, 69 different proteins predicted to be secreted were identified among 377 proteins. The reproducibility of the experiments is discussed. These proteins were distributed into eight functional classes. Oxidoreductases such as peroxidases were well represented, whereas glycoside hydrolases were scarce. This work provides information about the proteins that could be manipulated through genetic transformation, to increase second‐generation ethanol production.     

Links between plant and fungal communities across a deforestation chronosequence in the Amazon rainforest

Understanding the interactions among microbial communities, plant communities and soil properties following deforestation could provide insights into the long-term effects of land-use change on ecosystem functions, and may help identify approaches that promote the recovery of degraded sites. We combined high-throughput sequencing of fungal rDNA and molecular barcoding of plant roots to estimate fungal and plant community composition in soil sampled across a chronosequence of deforestation. We found significant effects of land-use change on fungal community composition, which was more closely correlated to plant community composition than to changes in soil properties or geographic distance, providing evidence for strong links between above- and below-ground communities in tropical forests.     

Quantitative analysis of race-specific resistance to Colletotrichum lindemuthianum in common bean

Molecular genetic maps continue to play a major role in breeding of crop species. The common bean genetic map of the recombinant inbred line population IAC-UNA × CAL 143 (UC) has been used to detect loci controlling important agronomic traits in common bean. In the current study, new microsatellite markers were added to the UC map and the linkage analysis was refined using current genomic resources of common bean, in order to identify quantitative resistance loci (QRL) associated with different races of the anthracnose pathogen. A single race inoculation was conducted in greenhouse using four plants per plot. Both race-specific and joint-adjusted disease severity means, obtained from linear-mixed model, were used to perform multiple interval mapping (MIM) and multi-trait MIM (MTMIM). In total, 13 and 11 QRL were identified by MIM and MTMIM analyses, respectively; with nine being observed in both analyses. ANT02.1^UC and ANT07.1^UC showed major effects on resistance both for MIM and MTMIM. Common major QRL for resistance to the three anthracnose races were expected, since high genetic pairwise-correlation was observed between the race-specific and joint-adjusted disease severity means. Therewith, both ANT02.1 and ANT07.1 can be regarded as valuable targets for marker-assisted selection; and so, putative genes potentially involved in the resistance response were identified in these QRL regions. Minor effect QRL were also observed, showing differential affects either on race-specific or multi-trait analyses and may play a role on durable horizontal resistance. These results contribute to a better understanding of the host-pathogen interaction and to breeding for enhancing resistance to Colletotrichum lindemuthianum in common bean.     

Field evaluation of (E)-2-hexenal efficacy for behavioral manipulation of egg parasitoids in soybean

We studied the influence of synthetic (E)-2-hexenal on the abundance of Telenominae aiming to attract parasitoids and enhance stink bug egg parasitism in treated areas. We conducted experiments in 2006, 2007 and 2008 soybean seasons with two short-term (one week) and one long-term (seven weeks) experiment, respectively. We evaluated the abundance of parasitoids with yellow sticky traps and estimated the incidence and intensity of parasitism with sentinel eggs of Euschistus heros Fabricius (Hemiptera: Pentatomidae) or with tulle bags, enclosing laboratory pregnant E. heros as an egg source. In short-term experiments, there was increased abundance of Trissolcus spp. (Hymenoptera: Platygastridae: Telenominae) in treated areas, associated with greater intensity of parasitism. In long-term experiments, treatment with (E)-2-hexenal did not influence the abundance of Telenominae or parasitism levels, but increased egg predation. Applications of (E)-2-hexenal can be used to increase recruitment of Trissolcus spp. in the early flowering stages of soybean and also to attract other natural enemies, but do not increase egg parasitism.     

Effects of artichoke (Cynara scolymus) leaf and bloom head extracts on chemically induced DNA lesions in Drosophila melanogaster

The genotoxicity of bloom head (BHE) and leaf (LE) extracts from artichoke (Cynara scolymus L.), and their ability to modulate the mutagenicity and recombinogenicity of two alkylating agents (ethyl methanesulfonate – EMS and mitomycin C – MMC) and the intercalating agent bleomycin (BLM), were examined using the somatic mutation and recombination test (SMART) in Drosophila melanogaster. Neither the mutagenicity nor the recombinogenicity of BLM or MMC was modified by co- or post-treatment with BHE or LE. In contrast, co-treatment with BHE significantly enhanced the EMS-induced genotoxicity involving mutagenic and/or recombinant events. Co-treatment with LE did not alter the genotoxicity of EMS whereas post-treatment with the highest dose of LE significantly increased this genotoxicity. This enhancement included a synergistic increase restricted to somatic recombination. These results show that artichoke extracts promote homologous recombination in proliferative cells of D. melanogaster.     

Pollen and stomata morphometrics and polyploidy in Eriotheca (Malvaceae‐Bombacoideae)

Approximately 70% of the angiosperm species are polyploid, an important phenomenon in the evolution of those plants. But ploidy estimates have often been hindered because of the small size and large number of chromosomes in many tropical groups. Since polyploidy affects cell size, morphometric analyses of pollen grains and stomata have been used to infer ploidy level. Polyploidy is present in many species of the Cerrado, the Neotropical savanna region in Central Brazil, and has been linked to apomixis in some taxa. Eriotheca gracilipes and Eriotheca pubescens are common tree species in this region, and present cytotypes that form reproductive mosaics. Hexaploid individuals (2n = 6x = 276) are polyembryonic and apomictic, while tetraploid and diploid individuals (2n = 2x = 92, 2n = 4x = 184) are sexual and monoembryonic. We tested whether morphometric analysis can be used to estimate ploidy levels in E. gracilipes and E. pubescens individuals. Pollen material from diploid and hexaploid individuals of E. gracilipes, and tetraploid and hexaploid individuals of E. pubescens, were fixed in 50% FAA, and expanded leaves were dried in silica gel. Pollen grains and stomata of at least five individuals from each population were measured. The results demonstrate that all measures were significantly different among cytotypes. Individuals with higher levels of ploidy (hexaploid) all presented measurements that were higher than those with lower levels (diploid and tetraploid). There was no overlap between ploidy levels in each species at 95% confidence interval. Thus, the size of the pollen grains and stomata are effective parameters for analysis of ploidy levels in E. gracilipes and E. pubescens.