Comparative Study of Bacillus-Based Plant Biofertilizers: A Proposed Index.

The market for bacteria as agricultural biofertilizers is growing rapidly, offering plant-growth stimulants; biofungicides; and, more recently, protectors against extreme environmental factors, such as drought. This abundance makes it challenging for the end user to decide on the product to use. In this work, we describe the isolation of a strain of Bacillus velezensis (belonging to the operational group Bacillus amyloliquefaciens) for use as a plant-growth-promoting rhizobacterium, a biofungicide, and a protector against drought. To compare its effectiveness with other commercial strains of the same operational group, Bacillus amyloliquefaciens, we analyzed its ability to promote the growth of pepper plants and protect them against drought, as well as its fungicidal activity through antibiosis and antagonism tests, its ability to solubilize potassium and phosphates, and its ability to produce siderophores. Finally, we used a probit function, a type of regression analysis used to model the outcomes of analyses, to quantify the biostimulatory effectiveness of the different plant-growth-promoting rhizobacteria, developing what we have called the Agricultural Protection Against Stress Index, which allowed us to numerically compare the four commercial strains of the operational group Bacillus amyloliquefaciens, based on a Delphi method-a type of regression analysis that can be used to model a cumulative normal distribution-and integrate the results from our panel of tests into a single value.

Design and proof of concept of a double-panel TOF-PET system.

OBJECTIVE: Positron Emission Tomography (PET) is a well-known imaging technology for the diagnosis, treatment, and monitoring of several diseases. Most PET scanners use a Ring-Shaped Detector Configuration (RSDC), which helps obtain homogeneous image quality but are restricted to an invariable Field-of-View (FOV), scarce spatial resolution, and low sensitivity. Alternatively, few PET systems use Open Detector Configurations (ODC) to permit an accessible FOV adaptable to different target sizes, thus optimizing sensitivity. Yet, to compensate the lack of angular coverage in ODC-PET, developing a detector with high-timing performance is mandatory to enable Time-of-Flight (TOF) techniques during reconstruction. The main goal of this work is to provide a proof of concept PET scanner appropriate for constructing the new generation of ODC-PET suitable for biopsy guidance and clinical intervention during acquisition. The designed detector has to be compact and robust, and its requirements in terms of performance are spatial and time resolutions < 2 mm and < 200 ps, respectively. METHODS: The present work includes a simulation study of an ODC-PET based on 2-panels with variable distance. The image quality (IQ) and Derenzo phantoms have been simulated and evaluated. The phantom simulations have also been performed using a ring-shaped PET for comparison purposes of the ODC approach with conventional systems. Then, an experimental evaluation of a prototype detector that has been designed following the simulation results is presented. This study focused on tuning the ASIC parameters and evaluating the scintillator surface treatment (ESR and TiO2), and configuration that yields the best Coincidence Time Resolution (CTR). Moreover, the scalability of the prototype to a module of 64 × 64mm2 and its preliminary evaluation regarding pixel identification are provided. RESULTS: The simulation results reported sensitivity (%) values at the center of the FOV of 1.96, 1.63, and 1.18 for panel distances of 200, 250, and 300 mm, respectively. The IQ reconstructed image reported good uniformity (87%) and optimal CRC values, and the Derenzo phantom reconstruction suggests a system resolution of 1.6-2 mm. The experimental results demonstrate that using TiO2 coating yielded better detector performance than ESR. Acquired data was filtered by applying an energy window of ± 30% at the photopeak level. After filtering, best CTR of 230 ± 2 ps was achieved for an 8 × 8 LYSO pixel block with 2 × 2 × 12mm3 each. The detector performance remained constant after scaling-up the prototype to a module of 64 × 64mm2, and the flood map demonstrates the module's capabilities to distinguish the small pixels; thus, a spatial resolution < 2 mm (pixel size) is achieved. CONCLUSIONS: The simulated results of this biplanar scanner show high performance in terms of image quality and sensitivity. These results are comparable to state-of-the-art PET technology and, demonstrate that including TOF information minimizes the image artifacts due to the lack of angular projections. The experimental results concluded that using TiO2 coating provide the best performance. The results suggest that this scanner may be suitable for organ study, breast, prostate, or cardiac applications, with good uniformity and CRC.

Pitting the olive seed microbiome.

BACKGROUND: The complex and co-evolved interplay between plants and their microbiota is crucial for the health and fitness of the plant holobiont. However, the microbiota of the seeds is still relatively unexplored and no studies have been conducted with olive trees so far. In this study, we aimed to characterize the bacterial, fungal and archaeal communities present in seeds of ten olive genotypes growing in the same orchard through amplicon sequencing to test whether the olive genotype is a major driver in shaping the seed microbial community, and to identify the origin of the latter. Therefore, we have developed a methodology for obtaining samples from the olive seed's endosphere under sterile conditions. RESULTS: A diverse microbiota was uncovered in olive seeds, the plant genotype being an important factor influencing the structure and composition of the microbial communities. The most abundant bacterial phylum was Actinobacteria, accounting for an average relative abundance of 41%. At genus level, Streptomyces stood out because of its potential influence on community structure. Within the fungal community, Basidiomycota and Ascomycota were the most abundant phyla, including the genera Malassezia, Cladosporium, and Mycosphaerella. The shared microbiome was composed of four bacterial (Stenotrophomonas, Streptomyces, Promicromonospora and Acidipropionibacterium) and three fungal (Malassezia, Cladosporium and Mycosphaerella) genera. Furthermore, a comparison between findings obtained here and earlier results from the root endosphere of the same trees indicated that genera such as Streptomyces and Malassezia were present in both olive compartments. CONCLUSIONS: This study provides the first insights into the composition of the olive seed microbiota. The highly abundant fungal genus Malassezia and the bacterial genus Streptomyces reflect a unique signature of the olive seed microbiota. The genotype clearly shaped the composition of the seed's microbial community, although a shared microbiome was found. We identified genera that may translocate from the roots to the seeds, as they were present in both organs of the same trees. These findings set the stage for future research into potential vertical transmission of olive endophytes and the role of specific microbial taxa in seed germination, development, and seedling survival.

Thriving beneath olive trees: The influence of organic farming on microbial communities.

Soil health and root-associated microbiome are interconnected factors involved in plant health. The use of manure amendment on agricultural fields exerts a direct benefit on soil nutrient content and water retention, among others. However, little is known about the impact of manure amendment on the root-associated microbiome, particularly in woody species. In this study, we aimed to evaluate the effects of ovine manure on the microbial communities of the olive rhizosphere and root endosphere. Two adjacent orchards subjected to conventional (CM) and organic (OM) management were selected. We used metabarcoding sequencing to assess the bacterial and fungal communities. Our results point out a clear effect of manure amendment on the microbial community. Fungal richness and diversity were increased in the rhizosphere. The fungal biomass in the rhizosphere was more than doubled, ranging from 1.72 × 106 ± 1.62 × 105 (CM) to 4.54 × 106 ± 8.07 × 105 (OM) copies of the 18 S rRNA gene g-1 soil. Soil nutrient content was also enhanced in the OM orchard. Specifically, oxidable organic matter, total nitrogen, nitrate, phosphorous, potassium and sulfate concentrations were significantly increased in the OM orchard. Moreover, we predicted a higher abundance of bacteria in OM with metabolic functions involved in pollutant degradation and defence against pathogens. Lastly, microbial co-occurrence network showed more positive interactions, complexity and shorter geodesic distance in the OM orchard. According to our results, manure amendment on olive orchards represents a promising tool for positively modulating the microbial community in direct contact with the plant.

Phytochemical Analysis and Anti-Inflammatory Potential of Acanthus mollis L. Rhizome Hexane Extract.

The rhizomes of Acanthus mollis have traditionally been used for the treatment of several ailments involving inflammation. However, to the best of our knowledge, their chemical composition and pharmacological properties have not been studied until now. As a first approach, this study analyses the A. mollis rhizome hexane extract phytochemistry and its anti-inflammatory and antioxidant capacities in HepG2 and RAW 264.7 cell culture assays. Chemical profiling was performed with gas chromatography mass spectrometry without the modification of native molecules. Free phytosterols (such as ß-sitosterol) account for 70% of detected compounds. The anti-inflammatory capacity of the rhizome extract of A. mollis is mediated by the decrease in the NO production in RAW 264.7 that has previously been stimulated with lipopolysaccharide in a dose-dependent manner. Furthermore, HepG2 pre-treatment with the rhizome extract prevents any damage being caused by oxidative stress, both through ROS scavenge and through the antioxidant cellular enzyme system. In this respect, the extract reduced the activity of glutathione peroxidase and reductase, which were stimulated under oxidative stress conditions. Our results suggest that the extract from the rhizomes of A. mollis may constitute a potential source of natural products with anti-inflammatory activity and could validate the traditional use of A. mollis.

Bacterial inoculation of Quercus pyrenaica trees alters co-occurrence patterns but not the composition of the rhizosphere bacteriome in wild conditions.

Quercus pyrenaica is a woody species of high landscape value, however, its forests show an advanced state of degradation in the Iberian Peninsula. Afforestation typically has low success, thus, it is necessary to improve the fitness of oaks plantlets to be transplanted, for instance, by inoculating beneficial microorganisms. In adding microorganisms to ecosystems, there must be balanced efficacy with potential effects on native microbial communities. We addressed changes in diversity, richness, composition and co-occurrence networks of prokaryotic communities in the rhizosphere of inoculated and control trees outplanted to three different sites located in the Sierra Nevada National and Natural Park (Spain). After 18 months in wild conditions, we did not detect changes due to the inoculation in the richness, diversity and structure in none of the sites. However, we observed an increase in the complexity of the co-occurrence networks in two experimental areas. Modularization of the networks changed as a result of the inoculation, although the sense of the change depended on the site. Although it was impossible to unravel the effect of bacterial inoculation, our results highlighted that inoculation alters the association of rhizosphere bacteria without entailing other changes, so networks should be analysed prior to inoculating the plantlets.

Primary somatosensory cortex bidirectionally modulates sensory gain and nociceptive behavior in a layer-specific manner.

The primary somatosensory cortex (S1) is a hub for body sensation of both innocuous and noxious signals, yet its role in somatosensation versus pain is debated. Despite known contributions of S1 to sensory gain modulation, its causal involvement in subjective sensory experiences remains elusive. Here, in mouse S1, we reveal the involvement of cortical output neurons in layers 5 (L5) and 6 (L6) in the perception of innocuous and noxious somatosensory signals. We find that L6 activation can drive aversive hypersensitivity and spontaneous nocifensive behavior. Linking behavior to neuronal mechanisms, we find that L6 enhances thalamic somatosensory responses, and in parallel, strongly suppresses L5 neurons. Directly suppressing L5 reproduced the pronociceptive phenotype induced by L6 activation, suggesting an anti-nociceptive function for L5 output. Indeed, L5 activation reduced sensory sensitivity and reversed inflammatory allodynia. Together, these findings reveal a layer-specific and bidirectional role for S1 in modulating subjective sensory experiences.

Co-occurrence network analysis unveils the actual differential impact on the olive root microbiota by two Verticillium wilt biocontrol rhizobacteria.

BACKGROUND: Verticillium wilt of olive (VWO), caused by Verticillium dahliae Kleb, is one of the most threatening diseases affecting olive cultivation. An integrated disease management strategy is recommended for the effective control of VWO. Within this framework, the use of biological control agents (BCAs) is a sustainable and environmentally friendly approach. No studies are available on the impact that the introduction of BCAs has on the resident microbiota of olive roots. Pseudomonas simiae PICF7 and Paenibacillus polymyxa PIC73 are two BCAs effective against VWO. We examined the effects of the introduction of these BCAs on the structure, composition and co-occurrence networks of the olive (cv. Picual) root-associated microbial communities. The consequences of the subsequent inoculation with V. dahliae on BCA-treated plants were also assessed. RESULTS: Inoculation with any of the BCAs did not produce significant changes in the structure or the taxonomic composition of the 'Picual' root-associated microbiota. However, significant and distinctive alterations were observed in the topologies of the co-occurrence networks. The introduction of PIC73 provoked a diminution of positive interactions within the 'Picual' microbial community; instead, PICF7 inoculation increased the microbiota's compartmentalization. Upon pathogen inoculation, the network of PIC73-treated plants decreased the number of interactions and showed a switch of keystone species, including taxa belonging to minor abundant phyla (Chloroflexi and Planctomycetes). Conversely, the inoculation of V. dahliae in PICF7-treated plants significantly increased the complexity of the network and the number of links among their modules, suggestive of a more stable network. No changes in their keystone taxa were detected. CONCLUSION: The absence of significant modifications on the structure and composition of the 'Picual' belowground microbiota due to the introduction of the tested BCAs underlines the low/null environmental impact of these rhizobacteria. These findings may have important practical consequences regarding future field applications of these BCAs. Furthermore, each BCA altered the interactions among the components of the olive belowground microbiota in idiosyncratic ways (i.e. PIC73 strongly modified the number of positive relations in the 'Picual' microbiota whereas PICF7 mostly affected the network stability). These modifications may provide clues on the biocontrol strategies used by these BCAs.

Bacteriome dataset from the rhizosphere of trees in a Pinus pinaster and Pinus halepensis dominated forest subjected to drought conditions.

The Mediterranean basin is drastically affected by intense and frequent droughts, which jeopardize the diversity and survival of its forest, for example, Pinus pinaster forests. The dynamics of the bacterial communities inhabiting the rhizosphere of Pinus pinaster and other plants from a pine dominated forest under contrasting hydric conditions was monitored. The forest was located in Sierra de Oria (southeast Spain), and it was mainly composed by P. pinaster, P. halepensis, woody shrub species and herbaceous plants. 18 trees visually belonging to P. pinaster located along the perimeter and across the forest were selected for the analysis. All the trees were separated at least 50 m each other. Although all of them belonged to P. pinaster morphologically according to visual identification, the genotyping of the roots confirmed that they corresponded to P. pinaster, P. halepensis, and other plant species different from genus Pinus, although in the last case it was not possible to identify the plant species. At a distance less than 50 cm from the trunk, the litter and topsoil were removed, and the soil closely attached to non-suberified roots (rhizosphere soil) was collected (depth of 5-25 cm). Sampling was carried out in two seasons with contrasting temperature and rainfall patterns: on July 18, 2017 (summer) and April 24, 2018 (spring). After rhizosphere soil DNA and RNA extraction (and cDNA synthesis), a metabarcoding approach was followed by sequencing the V3-V4 hypervariable regions of the 16S rRNA gene and its derived transcripts by Illumina MiSeq platform. Sequencing reads were bioinformatically processed; specifically, they were filtered, trimmed, clustered into ASV (Amplicon Sequence Variants), and taxonomically identified. As a result, a total of 1,123,209 and 1,089,359 quality sequences were obtained from DNA and RNA-derived libraries, which resulted in 5,241 and 5,231 ASVs, respectively. Total communities (DNA) were mainly dominated by phyla Proteobacteria, Acidobacteria, Actinobacteria, Verrucomicrobia and Bacteroidetes in summer and spring, while potentially active populations (RNA libraries) were rich in Proteobacteria, Acidobacteria, Candidate division WPS-1, Actinobacteria and Verrucomicrobia both in summer and spring. On the other hand, DNA libraries were mainly dominated by genera Sphingomonas and acidobacterial groups Gp4 and Gp6, while potentially active bacteria (RNA) were rich in acidobacterial Gp3, Gp4, Gp6 and Phenylobacterium, although their relative abundance depended on the considered season. This dataset can provide valuable information about bacterial candidates which could be used as bioindicators of drought conditions. In addition to shifts in the bacterial relative abundance due to seasonal changes, the ratio RNA-based cDNA:DNA could be calculated as proxy of the potential activity of bacterial taxa. Moreover, these data could aid in developing bioformulations based on microorganisms which could be resistant to desiccation and involved in the drought resistance mechanisms of the host plant.

Timing, Energy, and Spatial Characterization of Highly Sampled Monolithic PET Detectors with Different Thicknesses.

The HyPET project proposes a hybrid dedicated TOF-PET for prostate imaging, with pixelated detector blocks in the front layer and monolithic blocks in the back layer. In this work, four detector configurations have been experimentally evaluated for the rear detector layer. The detector configuration consists of LYSO monolithic blocks with the same size (25.4 mm × 25.4 mm) but different thicknesses (5, 7.5, 10, and 15 mm) coupled to the same SiPM array. Each detector configuration has been experimentally characterized in terms of time, energy and spatial resolution by scanning the crystal surface using a fan beam in steps of 0.25 mm. Regarding spatial resolution, the interaction position was estimated using a Neural Network technique. All resolutions except energy, which remains nearly constant at 17% for all cases, show better values for the 5 mm detector thickness. We have achieved spatial resolution values of FWHM of 1.02 ± 0.10, 1.19 ± 0.13, 1.53 ± 0.17, 2.33 ± 0.55 mm, for the 5, 7.5, 10, and 15 mm blocks, respectively. The detector time resolution obtained was 275 ± 26, 291 ± 21, 344 ± 48, and 433 ± 45 ps respectively, using the energy weighted average method for the time stamps.