Shifting abundances of communities associated with nitrogen cycling in soils promoted by sugarcane harvest systems.

Sugarcane cultivation supports Brazil as one of the largest world sugar and ethanol producer. In order to understand the impact of changing sugarcane harvest from manual to mechanized harvest, we studied the effect of machinery traffic on soil and consequently soil compaction upon soil microbial communities involved in nitrogen cycling. The impact of sugarcane harvest was dependent on soil depth and texture. At deeper soil layers, mechanized harvesting increases the abundance of nitrogen fixers and denitrifying communities (specifically nosZ clade I and II) while manual harvesting increases the abundance of ammonia oxidizers (specifically AOA) and increases denitrifying communities (nosZ clade I and II) on top and at intermediate depth. The effect of change on the harvest system is more evident on sandy soil than on clay soil, where soil indicators of compaction (bulk density and penetration resistance) were negatively correlated with soil microorganisms associated with the nitrogen cycle. Our results point to connections between soil compaction and N transformations in sugarcane fields, besides naming biological variables to be used as proxies for alterations in soil structure.

Correction to: G3BP1 knockdown sensitizes U87 glioblastoma cell line to Bortezomib by inhibiting stress granules assembly and potentializing apoptosis.

In the initial online version of the article, author F.M. Soriani was missing. The original article has been corrected.

G3BP1 knockdown sensitizes U87 glioblastoma cell line to Bortezomib by inhibiting stress granules assembly and potentializing apoptosis.

INTRODUCTION: Glioblastoma multiforme (GBM) is the most lethal form of gliomas. New therapies are currently in development to tackle treatment limitations such as chemotherapy resistance. One mechanism of resistance may be the stress granules (SG) assembly, a stress-related cellular response that allows cells to recruit and protect mRNAs during stress. SG are composed of various proteins, being G3BP1 a core element that enucleates and results in SG assembly. Here, we aimed to evaluate the effects of inhibiting the G3PB1 expression in the chemotherapeutical-induced cell death of the U87 glioblastoma cell line. MATERIALS AND METHODS: G3BP1 mRNA and protein expression were modulated with short-interference RNA (siRNA). The viability of U87 cells after Bortezomib (BZM), a proteasome inhibitor, and Temozolomide (TMZ), an alkylating agent, was assessed by MTT assay. Apoptosis was evaluated by staining cells with Annexin-V/7-AAD and analyzing by flow cytometry. Caspase-3 activation was evaluated by immunoblotting. The chorioallantoic membrane in vivo assay was used to evaluate angiogenesis. RESULTS: When G3BP1 was knocked-down, the SG assembly was reduced and the BZM-treated cells, but not TMZ-treated cells, had a significant increase in the apoptotic response. Corroborating this data, we observed increased Caspase-3 activation in the BZM-treated and G3BP1-knocked-down cells when compared to vehicle-treated and scramble-transfected cells. Worth mentioning, the conditioned culture medium of G3BP1-knocked-down BZM-treated cells inhibited angiogenesis when compared to controls. CONCLUSION: Our data suggest G3BP1 knockdown diminishes SG formation and stimulates BZM-induced apoptosis of U87 cells in vitro, in addition to inhibiting glioblastoma-induced angiogenesis in vivo.

Eucalyptus growth promotion by endophytic Bacillus spp.

Clonal eucalyptus plantings have increased in recent years; however, some clones with high production characteristics have vegetative propagation problems because of weak root and aerial development. Endophytic microorganisms live inside healthy plants without causing any damage to their hosts and can be beneficial, acting as plant growth promoters. We isolated endophytic bacteria from eucalyptus plants and evaluated their potential in plant growth promotion of clonal plantlets of Eucalyptus urophylla x E. grandis, known as the hybrid, E. urograndis. Eighteen isolates of E. urograndis, clone 4622, were tested for plant growth promotion using the same clone. These isolates were also evaluated for indole acetic acid production and their potential for nitrogen fixation and phosphate solubilization. The isolates were identified by partial sequencing of 16S rRNA. Bacillus subtilis was the most prevalent species. Several Bacillus species, including B. licheniformis and B. subtilis, were found for the first time as endophytes of eucalyptus. Bacillus sp strain EUCB 10 significantly increased the growth of the root and aerial parts of eucalyptus plantlets under greenhouse conditions, during the summer and winter seasons.