Neuronal NOS Inhibitor and Conventional Antidepressant Drugs Attenuate Stress-induced Fos Expression in Overlapping Brain Regions

Recent evidence indicates that the administration of inhibitors of neuronal nitric oxide synthase (nNOS) induces antidepressant-like effects in animal models such as the forced swimming test (FST). However, the neural circuits involved in these effects are not yet known. Therefore, this study investigated the expression of Fos protein, a marker of neuronal activity, in the brain of rats submitted to FST and treated with the preferential nNOS inhibitor, 7-nitroindazole (7-NI), or with classical antidepressant drugs (Venlafaxine and Fluoxetine). Male Wistar rats were submitted to a forced swimming pretest (PT) and, immediately after, started receiving a sequence of three ip injections (0, 5, and 23 h after PT) of Fluoxetine (10 mg/kg), Venlafaxine (10 mg/kg), 7-NI (30 mg/kg) or respective vehicles. One hour after the last drug injection the animals were submitted to the test session, when immobility time was recorded. After the FST they were sacrificed and had their brains removed and processed for Fos immunohistochemistry. Independent group of non-stressed animals received the same drug treatments, or no treatment (naïve). 7-NI, Venlafaxine or Fluoxetine reduced immobility time in the FST, an antidepressant-like effect. None of the treatments induce significant changes in Fos expression per se. However, swimming stress induced significant increases in Fos expression in the following brain regions: medial prefrontal cortex, nucleus accumbens, locus coeruleus, raphe nuclei, striatum, hypothalamic nucleus, periaqueductal grey, amygdala, habenula, paraventricular nucleus of hypothalamus, and bed nucleus of stria terminalis. This effect was attenuated by 7-NI, Venlafaxine or Fluoxetine. These results show that 7-NI produces similar behavioral and neuronal activation effects to those of typical antidepressants, suggesting that these drugs share common neurobiological substrates.     

MyD88 Signaling Pathway Is Involved in Renal Fibrosis by Favoring a TH2 Immune Response and Activating Alternative M2 Macrophages

Inflammation contributes to the pathogenesis of chronic kidney disease (CKD). Molecules released by the inflamed injured tissue can activate toll-like receptors (TLRs), thereby modulating macrophage and CD4⁺ T-cell activity. We propose that in renal fibrogenesis, M2 macrophages are recruited and activated in a T helper subset 2 cell (T_H2)-prone inflammatory milieu in a MyD88-dependent manner. Mice submitted to unilateral ureteral ligation (UUO) demonstrated an increase in macrophage infiltration with collagen deposition after 7 d. Conversely, TLR2, TLR4 and MyD88 knockout (KO) mice had an improved renal function together with diminished T_H2 cytokine production and decreased fibrosis formation. Moreover, TLR2, TLR4 and MyD88 KO animals exhibited less M2 macrophage infiltration, namely interleukin (IL)-10⁺ and CD206⁺ CD11b^high cells, at 7 d after surgery. We evaluated the role of a T_H2 cytokine in this context, and observed that the absence of IL-4 was associated with better renal function, decreased IL-13 and TGF-β levels, reduced arginase activity and a decrease in fibrosis formation when compared with IL-12 KO and wild-type (WT) animals. Indeed, the better renal outcomes and the decreased fibrosis formation were restricted to the deficiency of IL-4 in the hematopoietic compartment. Finally, macrophage depletion, rather than the absence of T cells, led to reduced lesions of the glomerular filtration barrier and decreased collagen deposition. These results provide evidence that future therapeutic strategies against renal fibrosis should be accompanied by the modulation of the M1:M2 and T_H1:T_H2 balance, as T_H2 and M2 cells are predictive of fibrosis toward mechanisms that are sensed by innate immune response and triggered in a MyD88-dependent pathway.     

Grassland management intensification affects the soil fauna in a subtropical highland

The conversion of natural grasslands to cultivated pastures can have a significant impact on the composition and structure of soil macro- and mesofauna groups, compromising the resilience of these organisms and the ecosystem services they provide. We studied the responses of these groups to increasing levels of soil disturbance across a gradient of four land management practices: Natural grassland (NG), Improved-natural grassland (IG), Perennial-cultivated pasture (PP), and Annual-cultivated pasture (AP). The NG area had a higher abundance of macrofauna, greater dominance of certain groups, particularly Isoptera, and a lower abundance of mesofauna. On the other hand, the IG area had a higher abundance and diversity of macro- and mesofauna, with a lower dominance of specific groups. The PP area had a higher abundance of Coleoptera, Oligochaeta, and Hemiptera, whereas the AP area, despite soil disturbance, showed a higher abundance of mesofauna, particularly mites, Collembola, and Enchytraeidae, but lower diversity. Different grassland management practices have significantly altered the composition and structure of macro- and mesofauna groups, resulting in high dissimilarity between communities. We recommend IG as a more productive and sustainable alternative to the total replacement of natural vegetation (NG) with intensified converted pastures (PP and AP), as it maintains soil fauna diversity and ecosystem services.     

A worldwide phylogenetic classification of the Poaceae (Gramineae) III: An update

We present an updated worldwide phylogenetic classification of Poaceae with 11 783 species in 12 subfamilies, 7 supertribes, 54 tribes, 5 super subtribes, 109 subtribes, and 789 accepted genera. The subfamilies (in descending order based on the number of species) are Pooideae with 4126 species in 219 genera, 15 tribes, and 34 subtribes; Panicoideae with 3325 species in 242 genera, 14 tribes, and 24 subtribes; Bambusoideae with 1698 species in 136 genera, 3 tribes, and 19 subtribes; Chloridoideae with 1603 species in 121 genera, 5 tribes, and 30 subtribes; Aristidoideae with 367 species in three generaand one tribe; Danthonioideae with 292 species in 19 generaand 1 tribe; Micrairoideae with 192 species in nine generaand three tribes; Oryzoideae with 117 species in 19 genera, 4 tribes, and 2 subtribes; Arundinoideae with 36 species in 14 genera and 3 tribes; Pharoideae with 12 species in three generaand one tribe; Puelioideae with 11 species in two generaand two tribes; and the Anomochlooideae with four species in two generaand two tribes. Two new tribes and 22 new or resurrected subtribes are recognized. Forty-five new (28) and resurrected (17) genera are accepted, and 24 previously accepted genera are placed in synonymy. We also provide an updated list of all accepted genera including common synonyms, genus authors, number of species in each accepted genus, and subfamily affiliation. We propose Locajonoa, a new name and rank with a new combination, L. coerulescens. The following seven new combinations are made in Lorenzochloa: L. bomanii, L. henrardiana, L. mucronata, L. obtusa, L. orurensis, L. rigidiseta, and L. venusta.     

Disulfide bridge formation influences ligand recognition by the ATAD2 bromodomain

The ATPase family, AAA domain-containing protein 2 (ATAD2) has a C-terminal bromodomain, which functions as a chromatin reader domain recognizing acetylated lysine on the histone tails within the nucleosome. ATAD2 is overexpressed in many cancers and its expression is correlated with poor patient outcomes, making it an attractive therapeutic target and potential biomarker. We solved the crystal structure of the ATAD2 bromodomain and found that it contains a disulfide bridge near the base of the acetyllysine binding pocket (Cys1057-Cys1079). Site-directed mutagenesis revealed that removal of a free C-terminal cysteine (C1101) residue greatly improved the solubility of the ATAD2 bromodomain in vitro. Isothermal titration calorimetry experiments in combination with the Ellman's assay demonstrated that formation of an intramolecular disulfide bridge negatively impacts the ligand binding affinities and alters the thermodynamic parameters of the ATAD2 bromodomain interaction with a histone H4K5ac peptide as well as a small molecule bromodomain ligand. Molecular dynamics simulations indicate that the formation of the disulfide bridge in the ATAD2 bromodomain does not alter the structure of the folded state or flexibility of the acetyllysine binding pocket. However, consideration of this unique structural feature should be taken into account when examining ligand-binding affinity, or in the design of new bromodomain inhibitor compounds that interact with this acetyllysine reader module.     

Aggregation of Cricket Activity in Response to Resource Addition Increases Local Diversity

Crickets are often found feeding on fallen fruits among forest litter. Fruits and other sugar-rich resources are not homogeneously distributed, nor are they always available. We therefore expect that crickets dwelling in forest litter have a limited supply of sugar-rich resource, and will perceive this and displace towards resource-supplemented sites. Here we evaluate how sugar availability affects cricket species richness and abundance in old-growth Atlantic forest by spraying sugarcane syrup on leaf litter, simulating increasing availability, and collecting crickets via pitfall trapping. We found an asymptotic positive association between resource addition and species richness, and an interaction between resource addition and species identity on cricket abundance, which indicates differential effects of resource addition among cricket species. Our results indicate that 12 of the 13 cricket species present in forest litter are maintained at low densities by resource scarcity; this highlights sugar-rich resource as a short-term driver of litter cricket community structure in tropical forests. When resource was experimentally increased, species richness increased due to behavioral displacement. We present evidence that the density of many species is limited by resource scarcity and, when resources are added, behavioral displacement promotes increased species packing and alters species composition. Further, our findings have technical applicability for increasing sampling efficiency of local cricket diversity in studies aiming to estimate species richness, but with no regard to local environmental drivers or species-abundance characteristics.     

Delimitation of the genus Schizachyrium (Poaceae,Andropogoneae) based on molecular and morphological data

Schizachyrium (Poaceae, Andropogoneae) includes about 60 species distributed in tropical and subtropical regions of the world. In all recent molecular phylogenies of Andropogoneae, representatives of Schizachyrium appear closely related to Andropogon species. The objective of this study was to contribute to the delimitation of Schizachyrium. We performed a phylogenetic study including 38 taxa (>63%) of Schizachyrium, along with representatives of related genera, mainly of Andropogon, yielding a total of 49 taxa. This is the first phylogenetic analysis to include the type species of Schizachyrium, S. condensatum. DNA sequences of two plastid markers (ndhF and trnL-F) were analyzed under Bayesian methods. The results indicate that Schizachyrium is not monophyletic: 26 of the 38 Schizachyrium taxa analyzed are placed in a Schizachyrium s.s. clade that includes the type species of the genus, while 10 taxa are related to Andropogon species and two other species, S. delavayi (from China and India) and S. jeffreysii (from Africa), appear clearly separated. Additionally, 58 morphological characters (41 qualitative and 17 quantitative) were scored for the same 49 taxa and analyzed under the parsimony criterion. Character optimizations showed that (i) the reduced pedicellate spikelets, (ii) with lower glume less than or equal to 0.5 mm wide, (iii) awned, and (iv) without lemma and palea support the Schizachyrium s.s. clade. We propose these four characters as diagnostic features for the delimitation of Schizachyrium s.s.