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Species differentiation and the appearance of novel diversity on Earth is a major issue to understand the past and future of microbial evolution. Herein, we propose the analysis of a singular evolutive example, the case of microorganisms carrying out the process of anammox (anaerobic ammonium oxidation). Anammox represents a singular physiology active on Earth from ancient times and, at present, this group is still represented by a relatively limited number of species carrying out a specific metabolism within the Phylum Planctomycetota. The key enzyme on the anammox pathway is hydrazine dehydrogenase (HDH) which has been used as a model in this study. HDH and rRNA (16S subunit) phylogenies are in agreement suggesting a monophyletic origin. The diversity of this singular phylogenetic group is represented by a few enriched bacterial consortia awaiting to be cultured as monospecific taxa. The apparent evolution of the HDH genes in these anammox bacteria is highly related to the diversification of the anammox clades and their genomes as pointed by phylogenomics, their GC content and codon usage profile. This study represents a clear case where bacterial evolution presents a paralleled genome, gene and species diversification through time from a common ancestor; a scenario that most times is masked by a web-like phylogeny and the huge complexity within the prokaryotes. Besides, this contribution suggests that microbial evolution of the anammox bacteria has followed an ordered, vertical diversification through Earth history and will present a potentially similar speciation fate in the future.

This article proposes a methodology for the optimal selection of the control strategy for two-axis solar tracking systems, that simultaneously reduces tracking error and energy consumption in existing solar tracking systems, improving their overall performance. Begins with the characterization of the tracking system, then the constraint definition helps to pre-select the possible controllers. Subsequently, a selection stage is carried out from a heuristic approach, based on a multibody simulation analysis and an experimental analysis, and the feasible controllers for the application of the tracker are defined. Finally, a comparative analysis is carried out to find the best control strategy for the existing tracker and the solar application. The optimal selection approach was implemented in a solar tracking system for low-power photovoltaic applications. Based on the defined constraints, six control strategies were pre-selected, which were simulated and implemented in the physical system. The multibody simulation process allows the designer to know the dynamics of each controller, and in turn determine an approximation of the best configuration of the elements that compose it. This, with the aim of validating that each proposal is compatible with the application of the solar tracker, and that it can be taken to the real experimental environment. From the experimental results, the MPC controller shows the best performance. Well, although it has a greater error than other alternatives, its value is still below the permissible precision level (less than 2°) and in turn has the lowest energy consumption 0.7867 Wh. That is, a reduction ranging from 34 to 76% with respect to each performance of the alternatives considered. In addition, the dynamics of the control actions it performs are smoother, thus reducing wear on the actuators.Thus, the results obtained to support that with the proposed methodology the overall performance of solar tracking systems can be increased, significantly reducing tracking error and energy consumption.

Abstract To test the feasibility of using profilometers to extract information about IOL surfaces design. A standard monofocal IOL (Tecnis 1), a monofocal IOL that provided some depth of focus (Eyhance), an extended depth of focus IOL based on refractive optics (Mini Well) and a trifocal IOL based on diffractive optics were used in this study (Tecnis Synergy). The surface topography of the IOLs was measured by using a multimode optical profilometer. Posterior surface of Tecnis 1 IOL was spherical and the anterior surface aspherical. In the Eyhance IOL, posterior surface was spherical and anterior surface did not fit to any of our reference surfaces, indicating a higher order aspheric surface design. In the Mini Well Ready IOL, a best-fit sphere surface was obtained for the second surface and a high order aspherical surface design was deduced for the first surface. The anterior surface of the Synergy IOL was aspherical and the base curve of the diffractive structure fitted very well to a spherical surface. To consider an aspheric surface as possible best-fit surface provided more information than if only best-fit spherical surface was considered. The high order aspheric surface designs employed in the IOLs studied presented differences, regarding best-fit asphere surface, higher than 1 micron. These differences were correlated with the generation of spherical aberration complex profiles (with Zernike terms higher than 4th order) and with the production of distinct amounts of depth of focus. This method was also useful to deduce the base curve of diffractive surfaces.

Abstract Aims The aims of the Asthma Academy study were to (1) evaluate the telehealth performance of DNP students, (2) evaluate the perceived learning experience of DNP students and (3) investigate whether an association exists related to student performance and family caregiver outcomes. Design A descriptive study was conducted with doctor of nursing practice students. Methods Students conducted telehealth visits to help family caregivers of children with asthma and were rated on their performance by two faculty members using a rubric. Student perception data were gathered via survey. Results Out of a total possible score of 15 points, the mean telehealth performance score of students was 13.38 points. Students indicated the telehealth experience was valuable and that they were satisfied with their learning. This model of leveraging telehealth to bridge nursing students to the community may be adapted to help family caregivers of children with various disease foci.

Objective: Pregnancy requires a complex physiological adaptation of the maternal cardiovascular system, which is disrupted in women with pregnancies complicated by preeclampsia, putting them at higher risk of future cardiovascular events. The measurement of body movements in response to cardiac ejection via ballistocardiogram (BCG) can be used to assess cardiovascular hemodynamics noninvasively in women with preeclampsia. Methods: Using a previously validated, modified weighing scale for assessment of cardiovascular hemodynamics through measurement of BCG and electrocardiogram (ECG) signals, we collected serial measurements throughout pregnancy and postpartum and analyzed data in 30 women with preeclampsia and 23 normotensive controls. Using BCG and ECG signals, we extracted measures of cardiac output, J-wave amplitude???heart rate (J-amp???HR). Mixed-effect models with repeated measures were used to compare J-amp???HRs between groups at different time points in pregnancy and postpartum. Results: In normotensive controls, the J-amp???HR was significantly lower early postpartum (E-PP) compared with the second trimester (T2; p?=?0.016) and third trimester (T3; p?=?0.001). Women with preeclampsia had a significantly lower J-amp???HR compared with normotensive controls during the first trimester (T1; p?=?0.026). In the preeclampsia group, there was a trend toward an increase in J-amp???HR from T1 to T2 and then a drop in J-amp???HR at T3 and further drop at E-PP. Conclusions: We observe cardiac hemodynamic changes consistent with those reported using well-validated tools. In pregnancies complicated by preeclampsia, the maximal force of contraction is lower, suggesting lower cardiac output and a trend in hemodynamics consistent with the hyperdynamic disease model of preeclampsia.

Microorganisms rule the functioning of our planet and each one of the individual macroscopic living creature. Nevertheless, microbial activity and growth status have always been challenging tasks to determine both in situ and in vivo. Microbial activity is generally related to growth, and the growth rate is a result of the availability of nutrients under adequate or adverse conditions faced by microbial cells in a changing environment. Most studies on microorganisms have been carried out under optimum or near-optimum growth conditions, but scarce information is available about microorganisms at slow-growing states (i.e., near-zero growth and maintenance metabolism). This study aims to better understand microorganisms under growth-limiting conditions. This is expected to provide new perspectives on the functions and relevance of the microbial world. This is because (i) microorganisms in nature frequently face conditions of severe growth limitation, (ii) microorganisms activate singular pathways (mostly genes remaining to be functionally annotated), resulting in a broad range of secondary metabolites, and (iii) the response of microorganisms to slow-growth conditions remains to be understood, including persistence strategies, gene expression, and cell differentiation both within clonal populations and due to the complexity of the environment.

During this century, a number of reports have described the potential roles of thermophiles in the upper soil layers during high-temperature periods. This study evaluates the capabilities of these microorganisms and proposes some potential consequences and risks associated with the activity of soil thermophiles. They are active in organic matter mineralization, releasing inorganic nutrients (C, S, N, P) that otherwise remain trapped in the organic complexity of soil. To process complex organic compounds in soils, these thermophiles require extracellular enzymes to break down large polymers into simple compounds, which can be incorporated into the cells and processed. Soil thermophiles are able to adapt their extracellular enzyme activities to environmental conditions. These enzymes can present optimum activity under high temperatures and reduced water content. Consequently, these microorganisms have been shown to actively process and decompose substances (including pollutants) under extreme conditions (i.e., desiccation and heat) in soils. While nutrient cycling is a highly beneficial process to maintain soil service quality, progressive warming can lead to excessive activity of soil thermophiles and their extracellular enzymes. If this activity is too high, it may lead to reduction in soil organic matter, nutrient impoverishment and to an increased risk of aridity. This is a clear example of a potential effect of future predicted climate warming directly caused by soil microorganisms with major consequences for our understanding of ecosystem functioning, soil health and the risk of soil aridity.

Sweet corn is one of the most important vegetables in North America and has undergone different selection pressures than non-sweet cultivars. Here, the authors report its genome assembly and reveal the evolutionary history of modern sweet corn through population genomic analyses.

Abstract Microorganisms govern soil carbon cycling with critical effects at local and global scales. The activity of microbial extracellular enzymes is generally the limiting step for soil organic matter mineralization. Nevertheless, the influence of soil characteristics and climate parameters on microbial extracellular enzyme activity (EEA) performance at different water availabilities and temperatures remains to be detailed. Different soils from the Iberian Peninsula presenting distinctive climatic scenarios were sampled for these analyses. Results showed that microbial EEA in the mesophilic temperature range presents optimal rates under wet conditions (high water availability) while activity at the thermophilic temperature range (60°C) could present maximum EEA rates under dry conditions if the soil is frequently exposed to high temperatures. Optimum water availability conditions for maximum soil microbial EEA were influenced mainly by soil texture. Soil properties and climatic parameters are major environmental components ruling soil water availability and temperature which were decisive factors regulating soil microbial EEA. This study contributes decisively to the understanding of environmental factors on the microbial EEA in soils, specifically on the decisive influence of water availability and temperature on EEA. Unlike previous belief, optimum EEA in high temperature exposed soil upper layers can occur at low water availability (i.e., dryness) and high temperatures. This study shows the potential for a significant response by soil microbial EEA under conditions of high temperature and dryness due to a progressive environmental warming which will influence organic carbon decomposition at local and global scenarios.

Abstract Fresh market sweet corn (Zea mays L.) is a row crop commercialized as a vegetable, resulting in strict expectations for ear size, color, and shape. Ear phenotyping in breeding programs is typically done manually and can be subjective, time consuming, and unreliable. Computer vision tools have enabled an inexpensive, high‐throughput, and quantitative alternative to phenotyping in agriculture. Here we present a computer vision tool using open‐source Python and OpenCV to measure yield component and quality traits relevant to sweet corn from photographs. This tool increases accuracy and efficiency in phenotyping through high‐throughput, quantitative feature extraction of traits typically measured qualitatively. EarCV worked in variable lighting and background conditions, such as under full sun and shade and against grass and dirt backgrounds. The package compares ears in images taken at varying distances and accurately measures ear length and ear width. It can measure traits that were previously difficult to quantify such as color, tip fill, taper, and curvature. EarCV allows users to phenotype any number of ears, dried or fresh, in any orientation while tolerating some debris and silk noise. The tool can categorize husked ears according to the predefined USDA quality grades based on length and tip fill. We show that the information generated from this computer vision approach can be incorporated into breeding programs by analyzing hybrid ears, capturing heritability of yield component traits, and detecting phenotypic differences between cultivars that conventional yield measurements cannot. Ultimately, computer vision can reduce the cost and resources dedicated to phenotyping in breeding programs.

Today, it is definitively accepted that microorganisms play a central role in the functioning and maintenance of our planet and the organisms thriving on it [...]

Plants have evolved a two-layered immune system consisting of pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). PTI and ETI are functionally linked, but also have distinct characteristics. Unraveling how these immune systems coordinate plant responses against pathogens is crucial for understanding the regulatory mechanisms underlying plant defense. Here we report integrative proteomic and phosphoproteomic analyses of the tomato-Pseudomonas syringae (Pst) pathosystem with different Pst mutants that allow the dissection of PTI and ETI. A total of 225 proteins and 79 phosphopeptides differentially accumulated in tomato leaves during Pst infection. The abundances of many proteins and phosphoproteins changed during PTI or ETI, and some responses were triggered by both PTI and ETI. For most proteins, the ETI response was more robust than the PTI response. The patterns of protein abundance and phosphorylation changes revealed key regulators involved in Ca2+ signaling, mitogen-activated protein kinase cascades, reversible protein phosphorylation, reactive oxygen species (ROS) and redox homeostasis, transcription and protein turnover, transport and trafficking, cell wall remodeling, hormone biosynthesis and signaling, suggesting their common or specific roles in PTI and/or ETI. A NAC (NAM, ATAF, and CUC family) domain protein and lipid particle serine esterase, two PTI-specific genes identified from previous transcriptomic work, were not detected as differentially regulated at the protein level and were not induced by PTI. Based on integrative transcriptomics and proteomics data, as well as qRT-PCR analysis, several potential PTI and ETI-specific markers are proposed. These results provide insights into the regulatory mechanisms underlying PTI and ETI in the tomato-Pst pathosystem, and will promote future validation and application of the disease biomarkers in plant defense.

Background: Caregivers of children with asthma demonstrate higher levels of anxious and depressive symptoms when compared to caregivers of healthy children.Objectives: The objectives of this study were to: 1) Evaluate feasibility and acceptability of two nurse-led, remotely offered interventions for caregivers of children with asthma; 2) Compare effectiveness of two interventions (a virtual education session and a virtual education session supplemented with a telehealth visit) in relation to caregiver outcomes, and 3) Assess the preliminary effect of the interventions on caregivers’ knowledge of asthma, sleep, anxiety and depressive symptoms.Methods: A mixed methods approach was used inclusive of a qualitative, descriptive design and randomized controlled trial design. Caregivers were provided virtual education and telehealth visits and evaluated from pre-posttest.Results: The intervention was found to be feasible and acceptable. Both the virtual education session and telehealth visit were effective. The intervention had a significant effect on caregiver's asthma knowledge and depressive symptoms (p

Soils are highly heterogeneous and support highly diverse microbial communities. Microbial extracellular enzymes breakdown complex polymers into small assimilable molecules representing the limiting step of soil organic matter mineralization. This process occurs on to soil particles although currently it is typically estimated in laboratory aqueous solutions. Herein, estimates of microbial extracellular enzyme activity were obtained over a broad range of temperatures and water availabilities frequently observed at soil upper layers. A Pseudomonas strain presented optimum extracellular enzyme activities at high water activity whereas a desiccation resistant bacterium (Deinococcus) and a soil thermophilic isolate (Parageobacillus) showed optimum extracellular enzyme activity under dried (i.e., water activities ranging 0.5–0.8) rather that wet conditions. Different unamended soils presented a distinctive response of extracellular enzyme activity as a function of temperature and water availability. This study presents a procedure to obtain realistic estimates of microbial extracellular enzyme activity under natural soil conditions of extreme water availability and temperature. Improving estimates of microbial extracellular enzyme activity contribute to better understand the role of microorganisms in soils.

Clavulanic acid (CLV) and amoxicillin, frequently administered in combination, can be independently involved in allergic reactions. Protein haptenation with β-lactams is considered necessary to activate the immune system. The aim of this study was to assess the suitability of biotinylated analogues of CLV as probes to study protein haptenation by this β-lactam. Two synthetic approaches afforded the labeling of CLV through esterification of its carboxylic group with a biotin moiety, via either direct binding (CLV-B) or tetraethylenglycol linker (CLV-TEG-B). The second analogue offered advantages as solubility in aqueous solution and potential lower steric hindrance for both intended interactions, with the protein and with avidin. NMR reactivity studies showed that both CLV and CLV-TEG-B reacts through β-lactam ring opening by aliphatic amino nitrogen, however with different stability of resulting conjugates. Unlike CLV conjugates, that promoted the decomposition of clavulanate fragment, the conjugates obtained with the CLV-TEG-B remained linked, as a whole structure including biotin, to nucleophile and showed a better stability. This was a desired key feature to allow CLV-TEG-B conjugated protein detection at great sensitivity. We have used biotin detection and mass spectrometry (MS) to detect the haptenation of human serum albumin (HSA) and human serum proteins. MS of conjugates showed that HSA could be modified by CLV-TEG-B. Remarkably, HSA preincubation with CLV excess only reduced moderately the incorporation of CLV-TEG-B, which could be attributed to different protein interferences. The CLV-TEG-B fragment with opened β-lactam was detected bound to the 404–430HSA peptide of the treated protein. Incubation of human serum with CLV-TEG-B resulted in the haptenation of several proteins that were identified by 2D-electrophoresis and peptide mass fingerprinting as HSA, haptoglobin, and heavy and light chains of immunoglobulins. Taken together, our results show that tagged-CLV keeps some of the CLV features. Moreover, although we observe a different behavior in the conjugate stability and in the site of protein modification, the similar reactivity indicates that it could constitute a valuable tool to identify protein targets for haptenation by CLV with high sensitivity to get insights into the activation of the immune system by CLV and mechanisms involved in β-lactams allergy.

Research Infrastructures (RIs) are large-scale facilities encompassing instruments, resources, data and services used by the scientific community to conduct high-level research in their respective fields. The development and integration of marine environmental RIs as European Research Vessel Operators [ERVO] (2020) is the response of the European Commission (EC) to global marine challenges through research, technological development and innovation. These infrastructures (EMSO ERIC, Euro-Argo ERIC, ICOS-ERIC Marine, LifeWatch ERIC, and EMBRC-ERIC) include specialized vessels, fixed-point monitoring systems, Lagrangian floats, test facilities, genomics observatories, bio-sensing, and Virtual Research Environments (VREs), among others. Marine ecosystems are vital for life on Earth. Global climate change is progressing rapidly, and geo-hazards, such as earthquakes, volcanic eruptions, and tsunamis, cause large losses of human life and have massive worldwide socio-economic impacts. Enhancing our marine environmental monitoring and prediction capabilities will increase our ability to respond adequately to major challenges and efficiently. Collaboration among European marine RIs aligns with and has contributed to the OceanObs’19 Conference statement and the objectives of the UN Decade of Ocean Science for Sustainable Development (2021–2030). This collaboration actively participates and supports concrete actions to increase the quality and quantity of more integrated and sustained observations in the ocean worldwide. From an innovation perspective, the next decade will increasingly count on marine RIs to support the development of new technologies and their validation in the field, increasing market uptake and produce a shift in observing capabilities and strategies.

Objective Although preterm delivery (PTD) before 34 weeks for severe hypertensive disease is a diagnostic criterion for antiphospholipid syndrome (APS), there is no consensus regarding testing for antiphospholipid antibodies (aPL) in this setting. We aim to describe the frequency of and the characteristics associated with inpatient aPL testing in this population. Study Design In this retrospective study of PTD before 34 weeks for severe hypertensive disease, charts were reviewed for aPL testing, gestational age at delivery, fetal complications, and severity of maternal disease. Wilcoxon rank-sum test, Fisher's exact, and chi-squared tests were used for analyses of continuous and categorical variables, and multivariate logistic regression for adjusted odds ratios. Results Among 133 cases, 14.3% had APS screening via aPL testing. Screened patients delivered earlier than unscreened patients (28.9 vs. 31.7 weeks, p

A report on 16S rRNA gene sequence re-analysis and digitalization is presented using Lysinibacillus species (one example) deposited in National Microbial Repositories in India. Lysinibacillus species 16S rRNA gene sequences were digitalized to provide quick response (QR) codes, Chaose Game Representation (CGR) and Frequency of Chaose Game Representation (FCGR). GC percentage, phylogenetic analysis, and principal component analysis (PCA) are tools used for the differentiation and reclassification of the strains under investigation. The seven reasons supporting the statements made by us as misclassified Lysinibacillus species deposited in National Microbial Depositories are given in this paper. Based on seven reasons, bacteria deposited in National Microbial Repositories such as Lysinibacillus and many other needs reanalyses for their exact identity. Leaves of identity with type strains of related species shows difference 2 to 8 % suggesting that reclassification is needed to correctly assign species names to the analyzed Lysinibacillus strains available in National Microbial Repositories. Keywords: 16S rRNA, Bacteria, Culture collection, DDH, Digitalization

Halogenated compounds are environmental pollutants toxic to humans and wildlife. Certain microorganisms degrade these halogenated compounds. However, little is known about the potential of microorganisms in bioremediation under extreme conditions, specifically in arid and semi-arid soils frequently exposed to high temperatures and desiccation periods. Arid and semi-arid environments and deserts make up vast areas of Earth's landmass. To investigate the degradation of 2-chlorophenol (2-CP) in soils as a function of temperature and water availability, three bacterial species were tested, two soil mesophiles of the genus Rhodococcus, R. opacus and R. erythropolis, and a soil thermophilic isolate, Parageobacillus thermoglucosidasius. Degradation trials in soil samples with these species were performed over a range of water activity from 1 to 0.4. At their optimum growth temperature, R. opacus showed maximum 2-CP degradation at water activity 0.9 sharply decreasing when lowering water activity. Nevertheless, the Parageobacillus isolate (optimum growth temperature 60°C) showed maximum 2-CP degradation rates at water activity 0.5 which represented highly desiccating conditions. Parageobacillus degradation of 2-CP was very low at water activity above 0.9. Thus, biodegradation of 2-CP in soils is possible even under arid conditions although different microbial species might be involved in this task depending on the interactions of abiotic factors and the diversity of microbial communities in soils. These results contribute to understand the potential biodegradation of specific halogenated compounds in the environment which is of great relevance to comprehend the fate of halogenated pollutants (i.e., 2-CP) in deserts, arid and semi-arid soils.

Lupus nephritis is a common manifestation of systemic lupus erythematosus (SLE). IgA nephropathy is a common type of primary glomerulonephritis. Renal manifestations in SLE patients are often due to lupus nephritis; however, renal diseases unrelated to lupus nephritis are rarely reported. While crescentic IgA nephropathy with rapid clinical progression is rare, its development in patients with SLE in the absence of lupus nephritis is even more unusual. A 74-year-old woman with a history of SLE without known renal involvement, chronic kidney disease stage IIIa, congestive heart failure, hypertension, and type 2 diabetes mellitus presented with acute kidney injury. Her creatinine continued to rise rapidly. Renal biopsy revealed mesangial proliferative glomerulonephritis with crescent formation. Immunofluorescent staining showed IgA and C3 mesangial deposition and absence of C4 and C1q, consistent with IgA nephropathy. She received a course of methylprednisolone and plasmapheresis. Unfortunately, her renal function continued to deteriorate, and she was started on hemodialysis which was continued after hospital discharge. This case illustrates crescentic IgA nephropathy without lupus nephritis as the cause of acute kidney injury in a patient with SLE. It highlights the observation that renal diseases other than lupus nephritis can develop in SLE patients.

Hydrolysis of polymers is a first and often limiting step during the degradation of plant residues. Plant biomass is generally a major component of waste residues and a major renewable resource to obtain a variety of secondary products including biofuels. Improving the performance of enzymatic hydrolysis of plant material with minimum costs and limiting the use of additional microbial biomass or hydrolytic enzymes directly influences competitiveness of these green biotechnological processes. In this study, we cloned and expressed a cellulase and two esterases recovered from environmental thermophilic soil bacterial communities and characterize their optimum activity conditions including the effect of several metal ions. Results showed that supplementing these hydrolytic reactions with Barium increases the activity of these extracellular hydrolytic enzymes. This observation represents a simple but major improvement to enhance the efficiency and competitiveness of this process within an increasingly important biotechnological sector.

The taxonomic concept of species has received continuous attention. A microbial species as a discrete box contains a limited number of highly similar microorganisms assigned to that taxon, following a polyphasic approach. In the 21st Century, with the advancements of sequencing technologies and genomics, the existence of a huge prokaryotic diversity has become well known. At present, the prokaryotic species might no longer have to be understood as discrete values (such as 1 or 2, by homology to Natural numbers); rather, it is expected that some microorganisms could be potentially distributed (according to their genome features and phenotypes) in between others (such as decimal numbers between 1 and 2; real numbers). We propose a continuous species concept for microorganisms, which adapts to the current knowledge on the huge diversity, variability and heterogeneity existing among bacteria and archaea. Likely, this concept could be extended to eukaryotic microorganisms. The continuous species concept considers a species to be delimited by the distance between a range of variable features following a Gaussian-type distribution around a reference organism (i.e., its type strain). Some potential pros and cons of a continuous concept are commented on, offering novel perspectives on our understanding of the highly diversified prokaryotic world, thus promoting discussion and further investigation in the field.

Many publications highlight the importance of nitric oxide (NO) in plant–bacteria interactions, either in the promotion of health and plant growth or in pathogenesis. However, the role of NO in the signaling between bacteria and plants and in the fate of their interaction, as well as the reconstruction of their interactive evolution, remains largely unknown. Despite the complexity of the evolution of life on Earth, we explore the hypothesis that denitrification and aerobic respiration were responsible for local NO accumulation, which triggered primordial antagonistic biotic interactions, namely the first phytopathogenic interactions. N-oxides, including NO, could globally accumulate via lightning synthesis in the early anoxic ocean and constitute pools for the evolution of denitrification, considered an early step of the biological nitrogen cycle. Interestingly, a common evolution may be proposed for components of denitrification and aerobic respiration pathways, namely for NO and oxygen reductases, a theory compatible with the presence of low amounts of oxygen before the great oxygenation event (GOE), which was generated by Cyanobacteria. During GOE, the increase in oxygen caused the decrease of Earth’s temperature and the consequent increase of oxygen dissolution and availability, making aerobic respiration an increasingly dominant trait of the expanding mesophilic lifestyle. Horizontal gene transfer was certainly important in the joint expansion of mesophily and aerobic respiration. First denitrification steps lead to NO formation through nitrite reductase activity, and NO may further accumulate when oxygen binds NO reductase, resulting in denitrification blockage. The consequent transient NO surplus in an oxic niche could have been a key factor for a successful outcome of an early denitrifying prokaryote able to scavenge oxygen by NO/oxygen reductase or by an independent heterotrophic aerobic respiration pathway. In fact, NO surplus could result in toxicity causing “the first disease” in oxygen-producing Cyanobacteria. We inspected in bacteria the presence of sequences similar to the NO-producing nitrite reductase nirS gene of Thermus thermophilus, an extreme thermophilic aerobe of the Thermus/Deinococcus group, which constitutes an ancient lineage related to Cyanobacteria. In silico analysis revealed the relationship between the presence of nirS genes and phytopathogenicity in Gram-negative bacteria.