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Transient receptor potential melastatin 3 (TRPM3) is a nonselective cation channel that is inhibited by Gβγ subunits liberated following activation of Gαi/oprotein-coupled receptors. Here, we demonstrate that TRPM3 channels are also inhibited by Gβγ released from Gαsand Gαq. Activation of the Gs-coupled adenosine 2B receptor and the Gq-coupled muscarinic acetylcholine M1 receptor inhibited the activity of TRPM3 heterologously expressed in HEK293 cells. This inhibition was prevented when the Gβγ sink βARK1-ct (C terminus of β-adrenergic receptor kinase-1) was coexpressed with TRPM3. In neurons isolated from mouse dorsal root ganglion (DRG), native TRPM3 channels were inhibited by activating Gs-coupled prostaglandin-EP2 and Gq-coupled bradykinin B2 (BK2) receptors. The Gi/oinhibitor pertussis toxin and inhibitors of PKA and PKC had no effect on EP2- and BK2-mediated inhibition of TRPM3, demonstrating that the receptors did not act through Gαi/oor through the major protein kinases activated downstream of G-protein-coupled receptor (GPCR) activation. When DRG neurons were dialyzed with GRK2i, which sequesters free Gβγ protein, TRPM3 inhibition by EP2 and BK2 was significantly reduced. Intraplantar injections of EP2 or BK2 agonists inhibited both the nocifensive response evoked by TRPM3 agonists, and the heat hypersensitivity produced by Freund's Complete Adjuvant (FCA). Furthermore, FCA-induced heat hypersensitivity was completely reversed by the selective TRPM3 antagonist ononetin in WT mice and did not develop inTrpm3−/−mice. Our results demonstrate that TRPM3 is subject to promiscuous inhibition by Gβγ protein in heterologous expression systems, primary neurons andin vivo, and suggest a critical role for this ion channel in inflammatory heat hypersensitivity.SIGNIFICANCE STATEMENTThe ion channel TRPM3 is widely expressed in the nervous system. Recent studies showed that Gαi/o-coupled GPCRs inhibit TRPM3 through a direct interaction between Gβγ subunits and TRPM3. Since Gβγ proteins can be liberated from other Gα subunits than Gαi/o, we examined whether activation of Gs- and Gq-coupled receptors also influence TRPM3 via Gβγ. Our results demonstrate that activation of Gs- and Gq-coupled GPCRs in recombinant cells and sensory neurons inhibits TRPM3 via Gβγ liberation. We also demonstrated that Gs- and Gq-coupled receptors inhibit TRPM3in vivo, thereby reducing pain produced by activation of TRPM3, and inflammatory heat hypersensitivity. Our results identify Gβγ inhibition of TRPM3 as an effector mechanism shared by the major Gα subunits.

Rickettsioses are re-emerging vector-borne zoonoses with a global distribution. Recently, Rickettsia sp. strain Atlantic rainforest has been associated with new human spotted-fever (SF) cases in Brazil, featuring particular clinical signs: eschar formation and lymphadenopathy. These cases have been associated with the tick species, Amblyomma ovale From 2010 until 2015, the Brazilian Health Department confirmed 11 human SF cases in the Maciço de Baturité region, Ceará, Brazil. The present study reports the circulation of Rickettsia spp. in vectors from this entirely new endemic area for SF. A total of 1,727 ectoparasites were collected in this area from the environment, humans, and wild and domestic animals. Samples (n = 887) were screened by polymerase chain reaction (PCR), targeting the gltA and ompA rickettsial genes. Sequencing and phylogenetic analyses of gltA gene amplicons were carried out for 13 samples positive for both screening PCRs. Fragments of gltA and ompA from three samples were cloned, sequenced, and analyzed further. A. ovale and Rhipicephalus sanguineus specimens, collected from dogs, were found to be infected with Rickettsia sp. str. Atlantic rainforest, suggesting the importance of dogs in the epidemic cycle. Candidatus Rickettsia andeanae, Rickettsia felis, and Rickettsia bellii were also found infecting ticks and fleas in five municipalities, demonstrating the broad diversity of rickettsiae in circulation in the studied area. This study reports, for the first time, evidence of infection with Rickettsia sp. strain Atlantic rainforest in A. ovale and R. sanguineus in Ceará, and Ca. R. andeanae in an Atlantic rainforest environment of Brazil.

Amblyomma nodosum ticks were collected from one collared anteater ( Tamandua tetradactyla) in the Caatinga biome, Brazil. From one sample, we isolated a Rickettsia sp. that was phylogenetically close to Rickettsia sp. strain NOD, with 99.9, 100.0, and 99.8% identity for gltA, htrA, and ompA genes, respectively.

In Brazil, Spotted Fever (SF) is caused by Rickettsia rickettsii and Rickettsia parkeri strain Atlantic Forest. In recent years, several human cases of a milder SF have been reported from the Macico de Baturite region of Ceara State. Previous studies in this region found R. parkeri strain Atlantic Forest to be present in Rhipicephalus sanguineus sensu lato and Amblyomma ovale ticks. The present study isolated and identified the Rickettsia spp. present in this new endemic area in Brazil. In March 2015, R. sanguineus s.l. and A. ovale were collected in rural areas of the Macico de Baturite region, and subjected to the isolation technique. A bacterium was isolated from one R. sanguineus s.l., which phylogenetic analysis clustered to the R. rickettsii group. In conclusion, R. rickettsii bacteria is circulating in the studied area and may in future have an impact on the clinical diagnoses and consequently cause changes in the profile of the disease in the region. In addition, we suggest the increase of epidemiological and environmental surveillance in the area, in order to prevent Brazilian Spotted Fever cases.

Among the several factors that may influence nodulation and the efficiency of biological nitrogen fixation for soybean plants, nutrient availability is among the most important. This study aimed to evaluate the inoculation with Bradyrhizobium japonicum and doses of phosphorus on the development of soybean in a Vertisol, in Tocantins. The experimental design was completely randomized in a 4 × 2 factorial scheme, with four replications. Four doses of phosphate fertilization (0, 100, 200, and 300 kg ha-1 P2O5) were studied, combined with two inoculation treatments with Bradyrhizobium japonicum (inoculated and not inoculated). The following variables were evaluated: plant height, stem diameter, nodules per plant, dry mass of nodules, dry mass of plant, dry mass of root, number of pods and number of grains per pod. Under greenhouse conditions and soil with good availability of phosphorus, there is no influence of the doses on the inoculation with Bradyrhizobium japonicum. Soils with good availability of phosphorus have low response to the application of phosphate fertilizer.

Despite the benefits of no-till practices, soil compaction is a problem that can cause, among other things, mechanical impediment to root growth and less response to soil fertilization. The objective of this study was to evaluate the effect of subsoiling and doses of phosphate fertilization on soybean that have been cultivated over ten years under no-till systems in the Brazilian Cerrado. The experiment consisted of a randomized complete block design in a 2 × 4 factorial arrangement. Two managements in consolidated no-tillage area were considered: with and without subsoiling, along with four levels of phosphate fertilization: 0, 100, 300 and 400 kg ha-1 of P2O5. The practice of subsoiling in an area with ten years of no-till system provided an increase of 124.38 kg ha-1 in soybean productivity. Soybean plants grown under no-tillage system, with subsoil management, showed better development and pod production. The maximum phosphorus efficiency, with subsoiling, was achieved with the dose of 172 kg ha-1 of P2O5, yielding 5,693.4 kg ha-1. In the no-tillage system, the maximum efficiency dose and crop yield were 159 kg ha-1 of P2O5 and 5434.2 kg ha-1, respectively.