An exceptional phytoplankton bloom in the southeast Madagascar Sea driven by African dust deposition.

Rising surface temperatures are projected to cause more frequent and intense droughts in the world's drylands. This can lead to land degradation, mobilization of soil particles, and an increase in dust aerosol emissions from arid and semi-arid regions. Dust aerosols are a key source of bio-essential nutrients, can be transported in the atmosphere over large distances, and ultimately deposited onto the ocean's surface, alleviating nutrient limitation and increasing oceanic primary productivity. Currently, the linkages between desertification, dust emissions and ocean fertilization remain poorly understood. Here, we show that dust emitted from Southern Africa was transported and deposited into the nutrient-limited surface waters southeast of Madagascar, which stimulated the strongest phytoplankton bloom of the last two decades during a period of the year when blooms are not expected. The conditions required for triggering blooms of this magnitude are anomalous, but current trends in air temperatures, aridity, and dust emissions in Southern Africa suggest that such events could become more probable in the future. Together with the recent findings on ocean fertilization by drought-induced megafires in Australia, our results point toward a potential link between global warming, drought, aerosol emissions, and ocean blooms.

Investigation of admission serum creatinine as a predictor of hospital length of stay in triple-vaccinated COVID-19 inpatients.

BACKGROUND: This study assessed the association between admission kidney function and the duration of hospitalization in triple-vaccinated coronavirus disease 2019 (COVID-19) inpatients during the omicron surge in Larissa, central Greece. METHODS: Regression analysis was used to estimate the effect of kidney function biomarkers on hospital length of stay (LoS) within a dataset from a cohort of 51 subjects. RESULTS: Sex- and age-adjusted admission serum creatinine was associated with hospital LoS (p=0.034). CONCLUSIONS: Serum creatinine concentration on admission should be further evaluated as a possible clinical predictor of hospital LoS among triple-vaccinated COVID-19 inpatients both at the country and global level.

The effect of cigarette smoke extract exposure on the size and sexual behaviour of Drosophila melanogaster.

Drosophila melanogaster is a widely used animal model in human diseases and to date it has not been applied to the study of the impact of tobacco use on human sexual function. Hence, this report examines the effects of different concentrations of cigarette smoke extract (CSE) exposure on the size and sexual behavior of D. melanogaster. Wild-type flies were held in vials containing CSE-infused culture media at concentrations of 10%, 25%, and 50% for three days, and their offspring were reared under the same conditions before measuring their body size and mating behavior. CSE exposure during development reduced the tibia length and body mass of emerging adult flies and prolonged the time required for successful courtship copulation success, while courtship behaviors (wing extension, tapping, abdomen bending, attempted copulation) remained largely unchanged. Our findings indicate that CSE exposure negatively affects the development of flies and their subsequent reproductive success. Future experiments should investigate the CSE effect on male female fertility.

Predictors of SARS-CoV-2 IgG Spike Antibody Responses on Admission and Clinical Outcomes of COVID-19 Disease in Fully Vaccinated Inpatients: The CoVax Study.

BACKGROUND: SARS-CoV-2 vaccines have shown high efficacy in protecting against COVID-19, although the determinants of vaccine effectiveness and breakthrough rates are yet to be determined. We aimed at investigating several factors affecting the SARS-CoV-2 IgG Spike (S) antibody responses on admission and clinical outcomes of COVID-19 disease in fully vaccinated, hospitalized patients. METHODS: 102 subjects were enrolled in the study. Blood serum samples were collected from each patient upon admission for the semiquantitative determination of the SARS-CoV-2 IgG S levels with lateral flow assays. Factors influencing vaccine responses were documented. RESULTS: 27 subjects had a negative antibody test upon hospital admission. Out of the 102 patients admitted to the hospital, 88 were discharged and 14 died. Both the absence of anti-S SARS-CoV-2 antibodies and poor clinical outcomes of COVID-19 disease were associated with older age, lower Ct values, and a shorter period between symptom onset and hospital admission. Ct values and time between symptom onset and hospitalization were independently associated with SARS-CoV-2 IgG S responses upon admission. The PaO2/FiO2 ratio was identified as an independent predictor of in-hospital mortality. CONCLUSIONS: Host- and disease-associated factors can predict SARS-CoV-2 IgG S responses and mortality in hospitalized patients with breakthrough SARS-CoV-2 Infection.

Grazing effect of flagellates on bacteria in response to phosphate addition in the oligotrophic Cretan Sea, NE Mediterranean.

The planktonic food web in the oligotrophic Mediterranean Sea is dominated by small-sized (<20 µm) microbes, with nanoflagellates being the major bacterial grazers and the main participants in nutrient cycling. Phosphate is a key nutrient in the P-limited Cretan Sea (NE Mediterranean) and P-availability can affect its trophic dynamics. Here, we examined the grazing potential of heterotrophic (HF) and pigmented (PF) nanoflagellates as a response mechanism to phosphate amendment. Flagellate grazing effect on bacteria was quantified in P-amended nutrient-depleted water from the Cretan Sea over the course of 4 days using microcosm experiments. P-addition positively affected HF abundance, while PF abundance remained unchanged. At the community level, P-addition had a negative effect on PF bacterial removal rates. In the control, PF-grazing rate was significantly higher than that of HF throughout the experiment. Pigment analysis showed no changes in phytoplankton community composition as a result of P-addition, indicating that PF grazing rate declined as a physiological response of the cells. The present study emphasizes the dominant grazing role of PF under P-depleted conditions and reveals that during the late stratified season PF respond to P-addition by lowering their grazing rates, enhancing the relative importance of bacterial removal by HF.