Unraveling brain fog in post-COVID syndrome: Relationship between subjective cognitive complaints and cognitive function, fatigue, and neuropsychiatric symptoms.

BACKGROUND AND PURPOSE: "Brain fog" is a frequent and disabling symptom that can occur after SARS-CoV-2 infection. However, its clinical characteristics and the relationships among brain fog and objective cognitive function, fatigue, and neuropsychiatric symptoms (depression, anxiety) are still unclear. In this study, we aimed to examine the characteristics of brain fog and to understand how fatigue, cognitive performance, and neuropsychiatric symptoms and the mutual relationships among these variables influence subjective cognitive complaints. METHODS: A total of 170 patients with cognitive complaints in the context of post-COVID syndrome were evaluated using a comprehensive neuropsychological protocol. The FLEI scale was used to characterize subjective cognitive complaints. Correlation analysis, regression machine-learning algorithms, and mediation analysis were calculated. RESULTS: Cognitive complaints were mainly attention and episodic memory symptoms, while executive functions (planning) issues were less often reported. The FLEI scale, a mental ability questionnaire, showed high correlations with a fatigue scale and moderate correlations with the Stroop test, and anxiety and depressive symptoms. Random forest algorithms showed an R2 value of 0.409 for the prediction of FLEI score, with several cognitive tests, fatigue and depression being the best variables used in the prediction. Mediation analysis showed that fatigue was the main mediator between objective and subjective cognition, while the effect of depression was indirect and mediated through fatigue. CONCLUSIONS: Brain fog associated with COVID-19 is mainly characterized by attention and episodic memory, and fatigue, which is the main mediator between objective and subjective cognition. Our findings contribute to understanding the pathophysiology of brain fog and emphasize the need to unravel the main mechanisms underlying brain fog, considering several aspects.

Spatial Variation in Yield, Chemical Composition, and Phytotoxic Activity of Cistus ladanifer Essential Oils.

Cistus ladanifer L. (rockrose) is a widespread shrub species of the Mediterranean region with products highly valued by the perfume and cosmetics industry. In this research, the variability in yield, chemical composition and phytotoxic activity of C. ladanifer essential oils collected from 12 plots belonging to four natural populations and settled on two different types of edaphic substrates were evaluated. The essential oils were analyzed by GC-MS. The essential oil content ranged from 0.19 to 0.42 mL/100 g. The volatile profiles were found to be rich in oxygenated sesquiterpenes and oxygenated monoterpenes. PCA analysis clustered the samples into two groups that were mainly attributed to the type of substrate on which the plants grow. Furthermore, CCA and correlation analysis revealed that soil organic matter was the most effective edaphoclimatic driver accounting for these high levels of variation in essential oil yield and composition. Finally, C. ladanifer essential oils showed strong phytotoxic activity on R. sativus seedlings, indicating its potential use as a natural bio-herbicide in agriculture. The results showed that the effect associated to local edaphoclimatic conditions not only impacted on the quality and quantity of the essential oil, but also on the industrial uses derived from its biological activities.

Examining Association of Personality Characteristics and Neuropsychiatric Symptoms in Post-COVID Syndrome.

BACKGROUND: We aimed to evaluate personality traits in patients with post-COVID syndrome, as well as the association with neuropsychiatric symptoms present in this disorder. METHODS: The Big Five Structure Inventory was administered to 93 consecutive patients with a diagnosis of post-COVID syndrome as defined by the WHO and to demographically matched controls. We also performed a comprehensive evaluation of depression, anxiety, fatigue, sleep quality, cognitive function, and olfactory function. RESULTS: Patients with post-COVID syndrome scored lower for emotional stability, equanimity, positive mood, and self-control. Extraversion, emotional stability, and openness correlated negatively with anxiety and depression levels. Conscientiousness correlated negatively with anxiety. No statistically significant correlations were observed between personality traits and cognitive function, sleep quality, olfactory function, or fatigue. Personality scores explained 36.3% and 41% of the variance in scores on the anxiety and depression scales, respectively. Two personality profiles with lower levels of emotional stability were associated with depression and anxiety. CONCLUSIONS: Our study shows higher levels of neuroticism in patients with post-COVID syndrome. Personality traits were predictive of the presence of depression and anxiety, but not cognitive function, sleep quality, or fatigue, in the context of post-COVID syndrome. These findings may have implications for the detection of patients at risk of depression and anxiety in post-COVID syndrome, and for the development of preventive and therapeutic interventions.

DNA Barcoding and geographical scale effect: The problems of undersampling genetic diversity hotspots.

DNA barcoding identification needs a good characterization of intraspecific genetic divergence to establish the limits between species. Yet, the number of barcodes per species is many times low and geographically restricted. A poor coverage of the species distribution range may hamper identification, especially when undersampled areas host genetically distinct lineages. If so, the genetic distance between some query sequences and reference barcodes may exceed the maximum intraspecific threshold for unequivocal species assignation. Taking a group of Quercus herbivores (moths) in Europe as model system, we found that the number of DNA barcodes from southern Europe is proportionally very low in the Barcoding of Life Data Systems. This geographical bias complicates the identification of southern query sequences, due to their high intraspecific genetic distance with respect to barcodes from higher latitudes. Pairwise intraspecific genetic divergence increased along with spatial distance, but was higher when at least one of the sampling sites was in southern Europe. Accordingly, GMYC (General Mixed Yule Coalescent) single-threshold model retrieved clusters constituted exclusively by Iberian haplotypes, some of which could correspond to cryptic species. The number of putative species retrieved was more reliable than that of multiple-threshold GMYC but very similar to results from ABGD and jMOTU. Our results support GMYC as a key resource for species delimitation within poorly inventoried biogeographic regions in Europe, where historical factors (e.g., glaciations) have promoted genetic diversity and singularity. Future European DNA barcoding initiatives should be preferentially performed along latitudinal gradients, with special focus on southern peninsulas.

Flowering synchrony drives reproductive success in a wind-pollinated tree.

Synchronised and quasi-periodic production of seeds by plant populations, known as masting, is implicated in many ecological processes, but how it arises remains poorly understood. Flowering and pollination dynamics are hypothesised to provide the mechanistic link for the observed relationship between weather and population-level seed production. We report the first experimental test of the phenological synchrony hypotheses as a driver of pollen limitation in mast seeding oaks (Quercus ilex). Higher flowering synchrony yielded greater pollination efficiency, which resulted in 2-fold greater seed set in highly synchronised oaks compared to asynchronous individuals. Pollen addition removed the negative effect of asynchronous flowering on seed set. Because phenological synchrony operates through environmental variation, this result suggests that oak masting is synchronised by exogenous rather than endogenous factors. It also points to a mechanism by which changes in flowering phenology can affect plant reproduction of mast-seeding plants, with subsequent implications for community dynamics.