Improving in-season wheat yield prediction using remote sensing and additional agronomic traits as predictors

The development of accurate grain yield (GY) multivariate models using normalized difference vegetation index (NDVI) assessments obtained from aerial vehicles and additional agronomic traits is a promising option to assist, or even substitute, laborious agronomic in-field evaluations for wheat variety trials. This study proposed improved GY prediction models for wheat experimental trials. Calibration models were developed using all possible combinations of aerial NDVI, plant height, phenology, and ear density from experimental trials of three crop seasons. First, models were developed using 20, 50 and 100 plots in training sets and GY predictions were only moderately improved by increasing the size of the training set. Then, the best models predicting GY were defined in terms of the lowest Bayesian information criterion (BIC) and the inclusion of days to heading, ear density or plant height together with NDVI in most cases were better (lower BIC) than NDVI alone. This was particularly evident when NDVI saturates (with yields above 8 t ha-1) with models including NDVI and days to heading providing a 50% increase in the prediction accuracy and a 10% decrease in the root mean square error. These results showed an improvement of NDVI prediction models by the addition of other agronomic traits. Moreover, NDVI and additional agronomic traits were unreliable predictors of grain yield in wheat landraces and conventional yield quantification methods must be used in this case. Saturation and underestimation of productivity may be explained by differences in other yield components that NDVI alone cannot detect (e.g. differences in grain size and number).This study was funded by the projects AGL2015-65351-R, PID2019-109089RB-C31 and TED2021-131606B-C21 of the Spanish Ministry of Economy and Competitiveness. AG-R was funded by a Margarita Salas post-doctoral contract from the Spanish Ministry of Universities affiliated to the Research Vice-Rector of the University of Barcelona. VRRY was funded by a pre-doctoral contract from the Spanish Ministry of Economy and Competitiveness (PRE2020-092369). The funders had no role in the study design, data collection and analysis, decision to publish, or manuscript preparation.The authors acknowledge the contribution of the CERCA Program (Generalitat de Catalunya). The authors acknowledge Andrea Lopez, Ezequiel Arqué, Jordi Companys, and Josep Millera for their technical contributions to the experimental setup of field trials.info:eu-repo/semantics/publishedVersio

Long Term Immune Responses to Pandemic Influenza A/H1N1 Infection in Solid Organ Transplant Recipients

In solid organ transplant (SOT) recipients it is unknown if natural infection with influenza confers protection from re-infection with the same strain during the next influenza season. The purpose of this study was to determine if infection with pandemic influenza A/H1N1 (pH1N1) resulted in a long-term immunologic response. Transplant recipients with microbiologically proven pH1N1 infection in 2009/2010 underwent humoral and cell-mediated immunity (CMI) testing for pH1N1 just prior to the next influenza season. Concurrent testing for A/Brisbane/59/2007 was done to rule-out cross-reacting antibody. We enrolled 22 adult transplant patients after pH1N1 infection. Follow up testing was done at a median of 7.4 months (range 5.8–15.4) after infection. After excluding those with cross-reactive antibody, 7/19 (36.8%) patients were seroprotected. Detectable pH1N1-specific CD4+ and CD8+ interferon-γ producing T-cells were found in 11/22 (50%) and 8/22 (36.4%) patients respectively. Humoral immunity had a significant correlation with a CD4 response. This is the first study in transplant patients to evaluate long-term humoral and cellular response after natural influenza infection. We show that a substantial proportion of SOT recipients with previous pH1N1 infection lack long-term humoral and cellular immune responses to pH1N1. These patients most likely are at risk for re-infection

Contribution of TAT System Translocated PhoX to Campylobacter jejuni Phosphate Metabolism and Resilience to Environmental Stresses

Campylobacter jejuni is a common gastrointestinal pathogen that colonizes food animals; it is transmitted via fecal contamination of food, and infections in immune-compromised people are more likely to result in serious long-term illness. Environmental phosphate is likely an important sensor of environmental fitness and the ability to obtain extracellular phosphate is central to the bacteria's core metabolic responses. PhoX is the sole alkaline phosphatase in C. jejuni, a substrate of the TAT transport system. Alkaline phosphatases mediate the hydrolytic removal of inorganic phosphate (Pi) from phospho-organic compounds and thereby contribute significantly to the polyphosphate kinase 1 (ppk1) mediated formation of poly P, a molecule that regulates bacterial response to stresses and virulence. Similarly, deletion of the tatC gene, a key component of the TAT system, results in diverse phenotypes in C. jejuni including reduced stress tolerance and in vivo colonization. Therefore, here we investigated the contribution of phoX in poly P synthesis and in TAT-system mediated responses. The phoX deletion mutant showed significant decrease (P<0.05) in poly P accumulation in stationary phase compared to the wild-type, suggesting that PhoX is a major contributor to the inorganic phosphate pool in the cell which is essential for poly P synthesis. The phoX deletion is sufficient for a nutrient stress defect similar to the defect previously described for the ΔtatC mutant. Additionally, the phoX deletion mutant has increased resistance to certain antimicrobials. The ΔphoX mutant was also moderately defective in invasion and intracellular survival within human intestinal epithelial cells as well as in chicken colonization. Further, the ΔphoX mutant produced increased biofilm that can be rescued with 1 mM inorganic phosphate. The qRT-PCR of the ΔphoX mutant revealed transcriptional changes that suggest potential mechanisms for the increased biofilm phenotype

Campylobacter jejuni transcriptome changes during loss of culturability in water

Background: Water serves as a potential reservoir for Campylobacter, the leading cause of bacterial gastroenteritis in humans. However, little is understood about the mechanisms underlying variations in survival characteristics between different strains of C. jejuni in natural environments, including water. Results: We identified three Campylobacter jejuni strains that exhibited variability in their ability to retain culturability after suspension in tap water at two different temperatures (4°C and 25°C). Of the three strains C. jejuni M1 exhibited the most rapid loss of culturability whilst retaining viability. Using RNAseq transcriptomics, we characterised C. jejuni M1 gene expression in response to suspension in water by analyzing bacterial suspensions recovered immediately after introduction into water (Time 0), and from two sampling time/temperature combinations where considerable loss of culturability was evident, namely (i) after 24 h at 25°C, and (ii) after 72 h at 4°C. Transcript data were compared with a culture-grown control. Some gene expression characteristics were shared amongst the three populations recovered from water, with more genes being up-regulated than down. Many of the up-regulated genes were identified in the Time 0 sample, whereas the majority of down-regulated genes occurred in the 25°C (24 h) sample. Conclusions: Variations in expression were found amongst genes associated with oxygen tolerance, starvation and osmotic stress. However, we also found upregulation of flagellar assembly genes, accompanied by down-regulation of genes involved in chemotaxis. Our data also suggested a switch from secretion via the sec system to via the tat system, and that the quorum sensing gene luxS may be implicated in the survival of strain M1 in water. Variations in gene expression also occurred in accessory genome regions. Our data suggest that despite the loss of culturability, C. jejuni M1 remains viable and adapts via specific changes in gene expression

Influenza vaccination for immunocompromised patients: systematic review and meta-analysis from a public health policy perspective.

Immunocompromised patients are vulnerable to severe or complicated influenza infection. Vaccination is widely recommended for this group. This systematic review and meta-analysis assesses influenza vaccination for immunocompromised patients in terms of preventing influenza-like illness and laboratory confirmed influenza, serological response and adverse events

Pre-Transplant HLA Immunization in Kidney Transplant Recipients Is Characterized by an Activated Peripheral B Cell Phenotype and High Serum Levels of BAFF

Transplantation and autoimmunit