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To estimate the frequency of headache in patients with confirmed COVID-19 and characterize the phenotype of headache attributed to COVID-19, comparing patients depending on the need of hospitalization and sex, an observational study was done. We systematically screened all eligible patients from a reference population of 261,431 between March 8 (first case) and April 11, 2020. A physician administered a survey assessing demographic and clinical data and the phenotype of the headache. During the study period, 2194 patients out of the population at risk were diagnosed with COVID-19. Headache was described by 514/2194 patients (23.4%, 95% CI 21.7–25.3%), including 383/1614 (23.7%) outpatients and 131/580 (22.6%) inpatients. The headache phenotype was studied in detail in 458 patients (mean age, 51 years; 72% female; prior history of headache, 49%). Headache was the most frequent first symptom of COVID-19. Median headache onset was within 24 h, median duration was 7 days and persisted after 1 month in 13% of patients. Pain was bilateral (80%), predominantly frontal (71%), with pressing quality (75%), of severe intensity. Systemic symptoms were present in 98% of patients. Headache frequency and phenotype was similar in patients with and without need for hospitalization and when comparing male and female patients, being more intense in females.Trial registration: This study was supported by the Institute of Health Carlos III (ISCIII), code 07.04.467804.74011 and Regional Health Administration, Gerencia Regional de Salud, Castilla y Leon (GRS: 2289/A/2020).

Grassland ecosystems are evolutionarily linked to disturbances such as grazing and fire. These disturbances define grassland plant communities and habitat heterogeneity, which influence animal communities. We evaluated the influence of fire disturbance on plant and bird communities and on habitat structure by sampling grassland fragments with different time elapsed since the last fire event. Habitat structure was sampled using plant life forms and abiotic variables and birds were sampled through point counts. We recorded 862 bird individuals from 70 species. Intermediately-burnt sites harbor higher habitat heterogeneity and plant species richness in comparison with recently or long-burnt sites. Bird abundance and taxonomic diversity decreased linearly as time since fire increased. Finally, time since fire influenced the relative distribution of plant life forms and bird food guilds. Our results indicate that fire management should be included in the framework for conservation and sustainable use of grasslands, because it promotes habitat heterogeneity and diversity. To maintain habitat heterogeneity and the related habitat-specific bird species and functional groups, conservation efforts should maintain grassland patches under different management intensities and frequencies on a landscape level. However, studies focused on determining the periodicity with which fire management should be used are still lacking.

Persistence phenotype and small colony variants (SCVs) can be part of a bacterial bet-hedging strategy for survival under environmental stresses, such as antimicrobial exposure. These phenotypes are of particular concern in persistent and relapsing infections, since cells resume to normal growth after cessation of the stressful condition. In this context, we found persisters and unstable SCVs as phenotypic variants of Salmonella enterica that were able to survive ciprofloxacin exposure. A high heterogeneity in persister levels was observed among S. enterica isolates grown under planktonic and biofilm conditions and exposed to ciprofloxacin or ceftazidime, which may indicate persistence as a non-multidrug-tolerant phenotype. Nevertheless, a comparable variability was not found in the formation of SCVs among the isolates. Indeed, similar proportions of SCV in relation to normal colony phenotype (NCP) were maintained even after three successive cycles of ciprofloxacin exposure testing colonies from both origins (SCV or NCP). Additionally, we found filamentous and dividing cells in the same scanning electron microscopy images from both SCV and NCP. These findings lead us to hypothesize that besides variability among isolates, a single isolate may generate distinct populations of persisters, where cells growing under distinct conditions may adopt different and perhaps complementary survival strategies.

Prenylated proteins play key roles in several human diseases including cancer, atherosclerosis and Alzheimer’s disease. KRAS4b, which is frequently mutated in pancreatic, colon and lung cancers, is processed by farnesylation, proteolytic cleavage and carboxymethylation at the C-terminus. Plasma membrane localization of KRAS4b requires this processing as does KRAS4b-dependent RAF kinase activation. Previous attempts to produce modified KRAS have relied on protein engineering approaches or in vitro farnesylation of bacterially expressed KRAS protein. The proteins produced by these methods do not accurately replicate the mature KRAS protein found in mammalian cells and the protein yield is typically low. We describe a protocol that yields 5–10 mg/L highly purified, farnesylated and methylated KRAS4b from insect cells. Farnesylated and methylated KRAS4b is fully active in hydrolyzing GTP, binds RAF-RBD on lipid Nanodiscs and interacts with the known farnesyl-binding protein PDEδ.