Activation of 5-hydroxytryptamine type 3 receptor-expressing c-fiber vagal afferents inhibits retrotrapezoid nucleus chemoreceptors in rats

Retrotrapezoid nucleus (RTN) chemoreceptors are regulated by inputs from the carotid bodies (CB) and from pulmonary mechanoreceptors. Here we tested whether RTN neurons are influenced by 5-hydroxytryptamine type 3 receptor-expressing C-fiber vagal afferents. in urethan-anesthetized rats, selective activation of vagal C-fiber afferents by phenylbiguanide (PBG) eliminated the phrenic nerve discharge (PND) and inhibited RTN neurons (n = 24). PBG had no inhibitory effect in vagotomized rats. Muscimol injection into the solitary tract nucleus, commissural part, reduced inhibition of PND and RTN by PBG (73%), blocked activation of PND and RTN by CB stimulation (cyanide) but had no effect on inhibition of PND and RTN by lung inflation. Bilateral injections of muscimol into interstitial solitary tract nucleus (NTS) reduced the inhibition of PND and RTN by PBG (53%), blocked the inhibitory effects of lung inflation but did not change the activation of PND and RTN neurons by CB stimulation. PBG and lung inflation activated postinspiratory neurons located within the rostral ventral respiratory group (rVRG) and inhibited inspiratory and expiratory neurons. Bilateral injections of muscimol into rVRG eliminated PND and partially decreased RTN neuron inhibition by PBG (32%). in conclusion, activation of cardiopulmonary C-fiber afferents inhibits the activity of RTN chemoreceptors. the pathway relays within a broad medial region of the NTS and involves the rVRG to a limited degree. the apnea triggered by activation of cardiopulmonary C-fiber afferents may be due in part to a reduction of the activity of RTN chemoreceptors.Univ Virginia Hlth Syst, Dept Pharmacol, Charlottesville, VA 22908 USAUniversidade Federal de São Paulo, Escola Paulista Med, Dept Physiol, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Physiol, São Paulo, BrazilWeb of Scienc

Effects of the inoculation with soil microbiota onmaize grown in saline soils

food and energetic needs will thus increase dramatically, while conventional agriculture is, even actually, facing drastic reductions in production yields and/or severe increases in cost to compensate losses in productivity due to lower soil fertility

Heavy metal accumulation in plant species indigenous to a contaminated portuguese site: prospects for phytoremediation

Phytoremediation is a promising alternative to conventional soil clean-up methods; however, up to date, there is still not enough information on plant species suitable for application in this field of science. Therefore, plant screening on contaminated sites can lead to the identification of further species of interest. In the present study, pedological and botanical characteristics of an industrialised area known for its metal contamination, in special with Zn—Esteiro de Estarreja, in Portugal—were examined in a 1-year screening. Twenty-seven species were found, with a higher occurrence and variability in the summer/spring season. Zinc levels in the tissues of the collected plant samples ranged from 34 mg kg−1 in shoots to 2,440 mg kg−1 in roots of different species. Species as Verbascum virgatum, Hypochoeris radicata, Phalaris arundinacea, Conyza bilbaoana, Paspalum urvillei and Aster squamatus have shown high Zn shoot accumulation and bioconcentration factors (BCFshoots > 1) and high metal translocation factors (TF > 1). Others, namely Spergularia capillacea, excluded Zn from the shoot tissues and stored the metal at the root zone (BCFroots > 1), behaving as tolerant plants. Plants were also screened for arbuscular mycorrhizal fungi colonisation, and only few species showed mycorrhizal presence, namely C. bilbaoana, Hirschfeldia incana, Epilobium tetragonum, Conyza sumatrensis, Pteridium aquilinum, P. urvillei and A. squamatus. The present work showed important indigenous species that can cope with installed harsh conditions and with potential for utilisation in phytoremediation strategies, either through metal removal to aerial parts or through its immobilisation in the root zone.info:eu-repo/semantics/acceptedVersio

Application of maize and efficient rhizospheric microorganisms for the remediation of saline soils

Soil salinity is a serious problem causing loss of fertility, as plants facing salt stress suffer alterations in physiology that adversely affects its growth. This work aimed to evaluate the effectiveness of combinations of microorganisms for the recovery of crop productivity in soils affected by different levels of salinity (0, 2.5 and 5 gNaCl.kg-1). The strategy relied on the culture in greenhouse conditions of a high value food and energetic crop (maize) inoculated with soil plant growth promoting microbiota – an arbuscular mychorrizal fungi (Rhizophagus irregularis), a rhizobacteria (Pseudomonas reactans) and a bacterial endophyte (Pantoea ananatis). Plant biomass was assessed at harvest and differences between treatments were analysed. As the work also aimed to relate the effects of bioinoculation to alterations in plant response to salt stress, further parameters were assessed. Elevated salt levels induce ionic stress, with consequent nutrient imbalance; therefore, levels of Na, K and Ca were determined in plant tissues. As salt is also a major stress to soil organisms, rhizosphere samples were analysed to follow up of microbiota survival by molecular biology techniques (DGGE), assessing the effect of soil salinity at the different tested levels on the inoculated soil microorganisms persistence and relationship with the existing community. The collected information allowed understanding the effects of the applied biologically based treatments in the quality of the tested saline soils, on the dynamics of the present microbiota and on maize growth, focusing on the further development of cropping strategies for saline soils, grounded on sustainable agriculture practices.info:eu-repo/semantics/publishedVersio

Paper-based platform with an in situ molecularly imprinted polymer for ß-amyloid

Alzheimers disease (AD) is one of the most common forms of dementia affecting millions of people worldwide. Currently, an easy and effective form of diagnosis is missing, which significantly hinders a possible improvement of the patients quality of life. In this context, biosensors emerge as a future solution, opening the doors for preventive medicine and allowing the premature diagnosis of numerous pathologies. This work presents a pioneering biosensor that combines a bottom-up design approach using paper as a platform for the electrochemical recognition of peptide amyloid -42 (A-42), a biomarker for AD present in blood, associated with visible differences in the brain tissue and responsible for the formation of senile plaques. The sensor layer relies on a molecularly imprinted polymer as a biorecognition element, created on the carbon ink electrodes surface by electropolymerizing a mixture of the target analyte (A-42) and a monomer (O-phenylenediamine) at neutral pH 7.2. Next, the template molecule was removed from the polymeric network by enzymatic and acidic treatments. The vacant sites so obtained preserved the shape of the imprinted protein and were able to rebind the target analyte. Morphological and chemical analyses were performed in order to control the surface modification of the materials. The analytical performance of the biosensor was evaluated by an electroanalytical technique, namely, square wave voltammetry. For this purpose, the analytical response of the biosensor was tested with standard solutions ranging from 0.1 ng/mL to 1 g/mL of A-42. The linear response of the biosensor went down to 0.1 ng/mL. Overall, the developed biosensor offered numerous benefits, such as simplicity, low cost, reproducibility, fast response, and repeatability less than 10%. All together, these features may have a strong impact in the early detection of AD.The authors acknowledge funding from project PTDC/AAGTEC/5400/2014, POCI-01-0145-FEDER-016637, POCI-01-0145-FEDER-007688, and UID/CTM/50025/2019 funded by European funds through FEDER (European Funding or Regional Development) via COMPETE2020 - POCI (operational program for internationalization and competitively) by national funding through the National Foundation for Science and Technology, I.P. (FCT-MCTES). Additionally, they are grateful to the project IBEROS, Instituto de Bioingenieria en Red para el Envejecimiento Saludable, POCTEP/0245-BEROS-1-E, PROGRAMA INTERREG 2014-2020 funded through FEDER within the cooperation region of Galiza/Spain and North of Portugal. A.C.M. and F.T.C.M. gratefully acknowledges FCT-MCTES for the financial support (PhD grant reference SFRH/BD/115173/2016 intituled “Nanobiosensing platform based on MIP-SERS for breast cancer exosome characterization and detection” and Post-Doc grant reference SFRH/BPD/97891/2013 intituled “Biomedical devices for easier and quicker screening procedures of the Alzheimer’s). This work is part of the Master Thesis in Micro and Nanotechnology Engineering defended by Marta V. Pereira. at FCT NOVA titled “Fabrication of 3D electrodes for biosensor applications” in December 2018.info:eu-repo/semantics/publishedVersio

Assessment of the plant growth promotion abilities of six bacterial isolates using Zea mays as indicator plant

Zea mays, one of the most important cereals worldwide, is a plant not only with food and energy value, but also with phytoremediation potential. The use of plant growth promoting (PGP) rhizobacteria may constitute a biological alternative to increase crop yield and plant resistance to degraded environments. In search for PGP rhizobacteria strains, 6 bacterial isolates were isolated from a metal contaminated site, screened in vitro for their PGP characteristics and their effects on the growth of Z. mays were assessed. Isolates were identified as 3A10T, ECP37T, corresponding to Chryseobacterium palustre and Chryseobacterium humi, and 1ZP4, EC15, EC30 and 1C2, corresponding to strains within the genera Sphingobacterium, Bacillus, Achromobacter, and Ralstonia, respectively. All the bacterial isolates were shown to produce indole acetic acid, hydrogen cyanide and ammonia when tested in vitro for their plant growth promoting abilities, but only isolates 1C2, 1ZP4 and ECP37T have shown siderophore production. Their further application in a greenhouse experiment using Z. mays indicated that plant traits such as root and shoot elongation and biomass production, and nutrient status, namely N and P levels, were influenced by the inoculation, with plants inoculated with 1C2 generally outperforming the other treatments. Two other bacterial isolates, 1ZP4 and ECP37T also led to increased plant growth in the greenhouse. These 3 species, corresponding to strains within the genera Ralstonia (1C2), Sphingobacterium (1ZP4), and to a strain identified as C. humi (ECP37T) can thus be potential agents to increase crop yield in maize plants.info:eu-repo/semantics/acceptedVersio