Population Structure and Genetic Diversity in Sweet Cassava Accessions in Paraná and Santa Catarina,Brazil

Plant Molecular Biology Reporter - Manihot esculenta Crantz is originally from the Amazon region of Brazil, which has the highest genetic diversity. Due to the wide adaptation of cassava to the...     

The interplay between local and landscape scales on the density of pond-dwelling anurans in subtropical grasslands

We investigated the role of local and landscape environmental variables on anurans density classified as habitat specialists and generalists in grassland landscapes, known as South Brazilian grasslands (SBG). In this region, we surveyed 187 ponds distributed over 40 landscape sampling units. For each pond, 31 local environmental variables were measured. Each landscape sampling unit was embedded within a larger regional sampling unit with different landscape properties. For each landscape and regional sampling units, 16 landscape metrics were extracted from a land cover and use map. We recorded 35 species, eleven of which are specialists in the SBG. The specialists were affected by 11 local and 2 landscape environmental variables, while generalists were affected by 14 local and one landscape environmental variable. Thus, specialists and generalists presented different relationships with local and landscape variables, but in general local variables had a greater influence on the density of anurans than the landscape variables. However, the landscape indirectly influenced local variables because higher quality ponds were in landscapes with higher percentages of natural habitat. In conclusion, reproductive sites with higher local quality and located within landscapes with higher percentages of natural grasslands are essential to conserve anurans in this habitat. Effective conservation of such sites would benefit from further studies that assess effects of land use and biotic integrity of ponds, which can help to determine (a) the relative effects of local habitat quality of ponds and (b) the effectiveness of protecting ponds and their local surroundings for anuran conservation in SBG. Abstract in Portuguese is available with online material.     

Experimental evidence of habitat selection and territoriality in the Amazonian whip spider Heterophrynus longicornis (Arachnida, Amblypygi)

Animals that select and defend suitable habitats against conspecifics may be favored by maximizing prey encounter rate, gaining protection, or securing matings. However, the identification of habitat selection and territoriality may be hindered in observational studies in sedentary species with low-density populations, such as the whip spider Heterophrynus longicornis. To circumvent such difficulties, we adopted an experimental field approach to evaluate if H. longicornis selects and defends habitat in Central Amazon. To evaluate whether individuals perform habitat selection, we monitored the permanence of 29 experimentally released individuals in buttressed trees with a wide variation in diameter at breast height (DBH), with and without burrows at their bases. To evaluate whether individuals are territorial, we experimentally removed 21 individuals from their previously occupied trees and monitored the recolonization of these trees. If H. longicornis were territorial, we predicted that the recolonizers would be smaller than the removed individuals. We found 12 individuals in the trees where they were released on subsequent days, none of them in trees without burrows. The individual permanence was related to the presence of burrows, and not to DBH. There was recolonization by smaller males and females on ten trees from which the amblypygids were removed. In combination, the permanence of individuals in trees with burrows, the rapid recolonization of experimentally vacated trees by smaller individuals, and the preponderance of one individual per tree, suggest that both male and female H. longicornis perform habitat selection and also that after selecting a site, they defend it against conspecifics.     

Ewing Sarcoma: influence of TP53 Arg72Pro and MDM2 T309G SNPs

The Ewing Sarcoma is an important tumor of bone and soft tissue. The SNPs Arg72Pro of TP53 and T309G of MDM2 have been associated with many cancer types and have been differently distributed among populations worldwide. Based on a case–control design, this study aimed to assess the role of these SNPs in 24 Ewing Sarcoma patients, compared to 91 control individuals. DNA samples were extracted from blood and genotyped for both SNPs by PCR–RFLP and confirmed by DNA sequencing. The results showed an association between the G allele of the T309G and Ewing Sarcoma (P = 0.02). Comparing to the TT carriers, the risk of G allele carriers was 3.35 (95 % CI = 1.22–9.21) with P = 0.02. At the genotypic level, an association of the TT genotype with the control group (P = 0.03) was found. Comparing to the TT genotype, the risk of TG and GG was 2.97 (95 % CI = 1.03–8.58) with P = 0.04 and 5.00 (95 % CI = 1.23–20.34) with P = 0.02, respectively. No associations regarding the Arg72Pro SNP were found. Considering that the T309G has been associated with several types of cancer, including sarcomas, our results indicate that this SNP may also be important to Ewing Sarcoma predisposition.     

Assessing the Subcellular Dynamics of Alpha-synuclein Using Photoactivation Microscopy

Alpha-synuclein (aSyn) is implicated in Parkinson’s disease and several other neurodegenerative disorders. To date, the function and intracellular dynamics of aSyn are still unclear. Here, we tracked the dynamics of aSyn using photoactivatable green fluorescent protein as a reporter. We found that the availability of the aSyn N terminus modulates its shuttling into the nucleus. Interestingly, familial aSyn mutations altered the dynamics at which the protein distributes throughout the cell. Both the A30P and A53T aSyn mutations increase the speed at which the protein moves between the nucleus and cytoplasm, respectively. We also found that specific kinases potentiate the shuttling of aSyn between nucleus and cytoplasm. A mutant aSyn form that blocks S129 phosphorylation, S129A, results in the formation of cytoplasmic inclusions, suggesting phosphorylation modulates aggregation in addition to modulating aSyn intracellular dynamics. Finally, we found that the molecular chaperone HSP70 accelerates the entry of aSyn into the nuclear compartment.     

Forward head posture is associated with pressure pain threshold and neck pain duration in university students with subclinical neck pain

Abstract

Objective: The aims of this study are to investigate the association between: (i) forward head posture (FHP) and pressure pain thresholds (PPTs); (ii) FHP and maladaptive cognitive processes; and (iii) FHP and neck pain characteristics in university students with subclinical neck pain.

Materials/methods: A total of 140 university students, 90 asymptomatic and 50 with subclinical neck pain, entered the study. Demographic data, anthropometric data, FHP, and PPTs were collected for both groups. In addition, pain characteristics, pain catastrophizing, and fear of movement were assessed for participants with neck pain. FHP was characterized by the angle between C7, the tragus of the ear, and the horizontal line. Correlation analysis and multivariate regression analysis were conducted.

Results: Participants with subclinical neck pain showed significantly lower PPTs than participants without neck pain (p?<?.05), but similar FHP (p?>?.05). No significant association was found between FHP and PPTs in the asymptomatic group. In the group of participants with subclinical neck pain, PPTs at the right trapezius and neck pain duration explained 19% of the variance of FHP (R²?=?0.23; adjusted R²?=?0.19; p?<?.05).

Conclusion: This study suggests that FHP is not associated with PPTs in asymptomatic university students. In university students with subclinical neck pain, increased FHP was associated with right trapezius hypoalgesia and with neck pain of shorter duration. These findings are in contrast with current assumptions on the association between neck pain and FHP.     

A predictive framework to assess spatio‐temporal variability of infestations by the European spruce bark beetle

Natural disturbances are key factors for the development of forest ecosystems. In forests of central Europe and Scandinavia, the European spruce bark beetle Ips typographus is the most devastating biotic disturbance agent in Norway spruce Picea abies, but our understanding of the factors determining its spatio‐temporal dynamics is still quite limited. To quantify the drivers of bark beetle dynamics, we analyzed a survey dataset with annual resolution that covers 17 yr and 469 forest districts (10 860 km² of forest area) all over Switzerland. We used Poisson log‐normal models in a Bayesian framework to analyze the spatio‐temporal dynamics of bark beetle infestation spots at the forest district level. Bark beetle infestations increased with increasing heat sum (> 8.3°C), volume of standing Norway spruce stock, and the number of infestation spots of the previous year. Precipitation tended to slightly affect the risk of bark beetle infestations. Two major storm events further increased the spatio‐temporal variability of bark beetle infestations. Spruce abundance, storm damage and temperature are known to be important factors influencing the population dynamics of the European spruce bark beetle. Our study is the first to quantify the combined effects of spruce abundance and heat sum, whereby the heat sum turned out to be the most important and consistent predictor. Because our study area encompasses large ecological and climatological gradients, our model is likely to be applicable to Norway spruce forests in other regions of central Europe and Scandinavia.     

Laminin‐γ1 chain and stress inducible protein 1 synergistically mediate PrPC‐dependent axonal growth via Ca2+ mobilization in dorsal root ganglia neurons

Prion protein (PrP^C) is a cell surface glycoprotein that is abundantly expressed in nervous system. The elucidation of the PrP^C interactome network and its significance on neural physiology is crucial to understanding neurodegenerative events associated with prion and Alzheimer's diseases. PrP^C co‐opts stress inducible protein 1/alpha7 nicotinic acetylcholine receptor (STI1/α7nAChR) or laminin/Type I metabotropic glutamate receptors (mGluR1/5) to modulate hippocampal neuronal survival and differentiation. However, potential cross‐talk between these protein complexes and their role in peripheral neurons has never been addressed. To explore this issue, we investigated PrP^C‐mediated axonogenesis in peripheral neurons in response to STI1 and laminin‐γ1 chain‐derived peptide (Ln‐γ1). STI1 and Ln‐γ1 promoted robust axonogenesis in wild‐type neurons, whereas no effect was observed in neurons from PrP^C‐null mice. PrP^C binding to Ln‐γ1 or STI1 led to an increase in intracellular Ca²⁺ levels via distinct mechanisms: STI1 promoted extracellular Ca²⁺ influx, and Ln‐γ1 released calcium from intracellular stores. Both effects depend on phospholipase C activation, which is modulated by mGluR1/5 for Ln‐γ1, but depends on, C‐type transient receptor potential (TRPC) channels rather than α7nAChR for STI1. Treatment of neurons with suboptimal concentrations of both ligands led to synergistic actions on PrP^C‐mediated calcium response and axonogenesis. This effect was likely mediated by simultaneous binding of the two ligands to PrP^C. These results suggest a role for PrP^C as an organizer of diverse multiprotein complexes, triggering specific signaling pathways and promoting axonogenesis in the peripheral nervous system.