Plant growth promoter collection of Gluconacetobacter diazotrophicus from northern coast of Peru

The application of plant growth promoting bacteria (PGPB) represents a friendly alternative to the environment, in contrast to the use of chemical fertilizers. Endophytic bacteria can develop inside the plant tissues and directly benefit the plant. Gluconacetobacter diazotrophicus is a versatile bacterium that has been isolated from different plants and possesses different physiological properties that would serve to improve plant development. In this research, five cultures of G. diazotrophicus were isolated from sugarcane samples from the northern coast of Peru. The isolates showed the ability to solubilize phosphates and zinc, produce IAA, and resist salt stress (NaCl 1%). Antagonism evaluations showed that they can inhibit up to 75%, 57%, 40%, 49% and 17% of the development of Fusarium sp., Alternaria sp., Roselinia sp., Lasiodiplodia sp., and Sclerotinia sp., respectively. Inoculation plant experiments were developed by inoculating individual and bacteria mixture. All treatments showed plant growth promotion in sugarcane, but mixture of G. diazotrophicus LASFB 1573, Klebsiella sp. LASFBP 086 and Enterobacter sp. LASFB 009 increased up to 84% and 89% in fresh and dry plant weight, respectively. The results show that the isolates have a high potential as PGPB and could be used later to improve the development of different crops

Computing the output distribution and selection probabilities of a stack filter from the DNF of its positive Boolean function

Many nonlinear filters used in practise are stack filters. An algorithm is presented which calculates the output distribution of an arbitrary stack filter S from the disjunctive normal form (DNF) of its underlying positive Boolean function. The so called selection probabilities can be computed along the way.Comment: This is the version published in Journal of Mathematical Imaging and Vision, online first, 1 august 201

Understanding and exploiting plant beneficial microbes

After a century of incremental research, technological advances, coupled with a need for sustainable crop yield increases, have reinvigorated the study of beneficial plant–microbe interactions with attention focused on how microbiomes alter plant phenotypes. We review recent advances in plant microbiome research, and describe potential applications for increasing crop productivity. The phylogenetic diversity of plant microbiomes is increasingly well characterized, and their functional diversity is becoming more accessible. Large culture collections are available for controlled experimentation, with more to come. Genetic resources are being brought to bear on questions of microbiome function. We expect that microbial amendments of varying complexities will expose rules governing beneficial plant–microbe interactions contributing to plant growth promotion and disease resistance, enabling more sustainable agriculture

Tomografía computarizada aplicada al estudio del esqueleto de los primeros vertebrados

Los conodontos son un grupo de vertebrados extintos que poseen unas piezas mineralizadas llamadas elementos conodontales. Aunque son importantes herramientas para datar y correlacionar, su importancia paleobiológica ha sido históricamente descuidada debido a su pequeño tamaño y las técnicas de estudio disponibles. El presente trabajo pretende hacer una revisión actualizada del conocimiento paleobiológico del grupo a la luz del uso de las nuevas técnicas tomográficas

Liquid antiferromagnets in two dimensions

It is shown that, for proper symmetry of the parent lattice, antiferromagnetic order can survive in two-dimensional liquid crystals and even isotropic liquids of point-like particles, in contradiction to what common sense might suggest. We discuss the requirements for antiferromagnetic order in the absence of translational and/or orientational lattice order. One example is the honeycomb lattice, which upon melting can form a liquid crystal with quasi-long-range orientational and antiferromagnetic order but short-range translational order. The critical properties of such systems are discussed. Finally, we draw conjectures for the three-dimensional case.Comment: 4 pages RevTeX, 4 figures include

Design of synthetic bacterial communities for predictable plant phenotypes

Specific members of complex microbiota can influence host phenotypes, depending on both the abiotic environment and the presence of other microorganisms. Therefore, it is challenging to define bacterial combinations that have predictable host phenotypic outputs. We demonstrate that plant–bacterium binary-association assays inform the design of small synthetic communities with predictable phenotypes in the host. Specifically, we constructed synthetic communities that modified phosphate accumulation in the shoot and induced phosphate starvation–responsive genes in a predictable fashion. We found that bacterial colonization of the plant is not a predictor of the plant phenotypes we analyzed. Finally, we demonstrated that characterizing a subset of all possible bacterial synthetic communities is sufficient to predict the outcome of untested bacterial consortia. Our results demonstrate that it is possible to infer causal relationships between microbiota membership and host phenotypes and to use these inferences to rationally design novel communities

LungBEAM: A prospective multicenter study to monitor stage IV NSCLC patients with EGFR mutations using BEAMing technology

Objectives: The aim of LungBEAM was to determine the value of a novel epidermal growth factor receptor (EGFR) mutation test in blood based on BEAMing technology to predict disease progression in advanced non-small cell lung cancer (NSCLC) patients treated with first- or second-generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs). Another goal was to monitor the dynamics of EGFR mutations, as well as to track EGFR exon 20 p.T790M (p.T790M) resistance during treatment, as critical indicators of therapeutic efficacy and patient survival. Methods: Stage IV NSCLC patients with locally confirmed EGFR-TKI sensitizing mutations (ex19del and/or L858R) in biopsy tissue who were candidates to receive first- or second-generation EGFR-TKI as first-line therapy were included. Plasma samples were obtained at baseline and every 4 weeks during treatment until a progression-free survival (PFS) event or until study completion (72-week follow-up). The mutant allele fraction (MAF) was determined for each identified mutation using BEAMing. Results: A total of 68 of the 110 (61.8%) patients experienced a PFS event. Twenty-six patients (23.6%) presented with an emergent p.T790M mutation in plasma at some point during follow-up, preceding radiologic progression with a median of 76 (interquartile ratio: 54–111) days. Disease progression correlated with the appearance of p.T790M in plasma with a hazard ratio (HR) of 1.94 (95% confidence interval [CI], 1.48–2.54; p < 0.001). The HR for progression in patients showing increasing plasma sensitizing mutation levels (positive MAF slope) versus patients showing either decreasing or unchanged plasma mutation levels (negative or null MAF slopes) was 3.85 (95% CI, 2.01–7.36; p < 0.001). Conclusion: Detection and quantification of EGFR mutations in circulating tumor DNA using the highly sensitive BEAMing method should greatly assist in optimizing treatment decisions for advanced NSCLC patients. © 2021 The Authors. Cancer Medicine published by John Wiley & Sons Ltd