Browsing by Issue Date, starting with "2025-09-05"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Electrophysiological responses of the clam (Ruditapes decussatus) osphradium to amino acids and alarm cuesPublication . Rato, Ana Cláudia Nunes; Costa, Joana; Gonçalves, Diana; Matias, Domitília; Joaquim, Sandra; Hubbard, PeterChemical sensing of the surrounding environment is crucial for many aspects of bivalve biology, such as food detection and predator avoidance. Aquatic organisms strongly depend on chemosensory systems; however, little is known about chemosensory systems in bivalves. To understand how the carpet shell clam (Ruditapes decussatus) senses its surrounding chemical environment, we used an electrophysiological technique – the electro-osphradiogram – to assess the sensitivity of the osphradium to different putative odorants (amino acids, bile acids) and odours (predator-released cues and signals from con- and heterospecific bivalves). The clam osphradium was sensitive to most proteinogenic L-amino acids, evoking negative, tonic, and concentration-dependent responses. However, acidic amino acids (L-glutamic and L-aspartic acid), L-arginine and bile acids (cholic, taurocholic and taurolithocholic acid) failed to evoke any response. Surprisingly, while cues from injured bivalves (con- and heterospecific) evoked strong responses, predator-released cues (green crab, Carcinus maenas) failed to elicit any response, whether fed or unfed. That predator-released cues failed to evoke an electrophysiological response in the clam osphradium may indicate that they use cues released by injured prey – alarm cues – to avoid predation and/or that predators are detected by different sensory modalities. Indeed, the behavioural assays, performed to understand how clams make use of such sensory inputs, revealed that the activity index decreased after exposure to water conditioned with injured conspecifics, suggesting the origin of such alarm cues. Further research is needed to identify the chemical nature of these cues. We suggest that the electro-osphradiogram will be a useful tool in this endeavour.
- Association of acute COVID-19 severity and long COVID fatigue and quality of life: prospective cohort multicenter observational studyPublication . Pires, Ligia; Marreiros, Ana; Saraiva, Cátia; Reis, Cláudia; Neves, Djamila; Guerreiro, Cláudia; Tomé, José Boleo; Luz, Maria Inês; Pereira, Margarida Isabel; Barroso, Ana Sofia; Ferreira, Jorge; Gonzalez, Lucía Méndez; Moniri, Armin; Drummond, Marta; Berger-Estilita, JoanaLong COVID, or post-COVID-19 condition, is characterized by symptoms persisting beyond 12 weeks after severe acute respiratory syndrome coronavirus 2 infection, affecting individuals regardless of acute disease severity. Fatigue – often linked with depression and anxiety – is among its most debilitating manifestations. However, the associations between fatigue subtypes (physical vs mental), mental health symptoms, and acute disease severity on long-term health-related quality of life (HRQoL) remain unclear. This study examines the relationships between long COVID fatigue, depression, anxiety, acute disease severity, and HRQoL in a post-COVID-19 cohort. This prospective observational cohort study was conducted across 5 Portuguese hospitals between November 2020 and June 2022. Adults (≥18 years) with confirmed severe acute respiratory syndrome coronavirus 2 infection ≥6 months prior and fulfilling World Health Organization criteria for long COVID were included. Acute Coronavirus disease 2019 (COVID-19) severity was classified per World Health Organization definitions. The sampling strategy included patients across the severity spectrum. At 3 months postinfection (T1), patients received physician-led clinical assessments. At 6 months (T2), they attended in-person follow-up visits, completing standardized forms and validated questionnaires assessing post-acute sequelae. Fatigue was reported both binarily (yes/no) and via the chalder fatigue scale (11-item version). Anxiety and depression were assessed using the hospital anxiety and depression scale; post-traumatic stress disorder symptoms with the 14-item post-traumatic stress scale; and HRQoL with the EuroQol-5 dimensions. Descriptive statistics, analysis of variance, chi-square, and correlation analyses (Pearson’s or Spearman’s) were used to evaluate associations. Analyses were performed using SPSS (v27; IBM Corp., Amonk). Among 208 patients, fatigue was significantly associated with anxiety and depression (P < .001). Physical fatigue correlated more strongly with depression (r = 0.65, P < .001) and anxiety (r = 0.58, P < .001) than mental fatigue (r = 0.50 and R = 0.48, respectively; P < .001). Surprisingly, severe acute COVID-19 cases reported lower fatigue (CFQ: 13.3 ± 8.4) than mild (17.7 ± 7.2) or moderate (17.4 ± 8.0) cases (P < .005), and higher HRQoL (EuroQol visual analog scale: 74.3 ± 20.3, P = .002). Anxiety symptoms were more common in mild cases (P < .001); post-traumatic stress disorder symptoms did not differ by severity. Long COVID fatigue – especially physical – is strongly linked to depression and anxiety. Mild/moderate acute COVID-19 cases show greater fatigue and lower HRQoL than severe cases, highlighting the need for tailored long-term care regardless of initial severity.