Horizontal biosedimentary gradients across the Sado estuary,W. Portugal

The topography of the Sado estuary, the second largest of Portugal, comprises the outer estuary inside the entrance channel and the inner estuary, on the inward side of which begins the tidal mudflats. The outer estuary subtidal area covers approximately 70 km² and presents a series of longitudinal intertidal sandbanks, separating a northern and a southern channel. A benthic survey was undertaken in the outer estuary during June 1986, in which superficial sediments and macrofauna were sampled at 133 locations. The environmental variables measured in the superficial sediments were the temperature, the granulometric structure, the silt, sand and the gravel content, and the total organic matter content. The primary macrofauna biological variables studied were the species composition, abundance and biomass, calculated on wet, dry and ash-free dry weight. The granulometry and the organic content of superficial sediments agreed with the transient and the residual currents velocity field, simulated in a 2-D hydrodynamic model previously elaborated for the outer estuary. The northern channel superficial sediments showed higher silt and total organic matter content, while the model also suggested lower transient and residual velocities, water flow and shear stress in this channel. The distribution patterns of the subtidal macrofauna were separated into two main groups of species, one comprising taxa essentially settled near the estuarine mouth and the other inwards. Biological primary variables also showed consistent patterns, comparable to other Portuguese estuaries. The major subtidal benthic biotopes were obtained through classification analysis and related to the prevailing hydrophysical and sedimentary conditions in the outer estuary.     

Design and preclinical testing of an anti-CD41 CAR T cell for the treatment of acute megakaryoblastic leukaemia

Acute megakaryoblastic leukaemia (AMkL) is a rare subtype of acute myeloid leukaemia (AML) representing 5% of all reported cases, and frequently diagnosed in children with Down syndrome. Patients diagnosed with AMkL have low overall survival and have poor outcome to treatment, thus novel therapies such as CAR T cell therapy could represent an alternative in treating AMkL. We investigated the effect of a new CAR T cell which targets CD41, a specific surface antigen for M7-AMkL, against an in vitro model for AMkL, DAMI Luc2 cell line. The performed flow cytometry evaluation highlighted a percentage of 93.8% CAR T cells eGFP-positive and a limited acute effect on lowering the target cell population. However, the interaction between effector and target (E:T) cells, at a low ratio, lowered the cell membrane integrity, and reduced the M7-AMkL cell population after 24 h of co-culture, while the cytotoxic effect was not significant in groups with higher E:T ratio. Our findings suggest that the anti-CD41 CAR T cells are efficient for a limited time spawn and the cytotoxic effect is visible in all experimental groups with low E:T ratio.     

COVID-19 plasma proteome reveals novel temporal and cell-specific signatures for disease severity and high-precision disease management

Coronavirus disease 2019 (COVID-19) is a systemic inflammatory condition with high mortality that may benefit from personalized medicine and high-precision approaches. COVID-19 patient plasma was analysed with targeted proteomics of 1161 proteins. Patients were monitored from Days 1 to 10 of their intensive care unit (ICU) stay. Age- and gender-matched COVID-19-negative sepsis ICU patients and healthy subjects were examined as controls. Proteomic data were resolved using both cell-specific annotation and deep-analysis for functional enrichment. COVID-19 caused extensive remodelling of the plasma microenvironment associated with a relative immunosuppressive milieu between ICU Days 3–7, and characterized by extensive organ damage. COVID-19 resulted in (1) reduced antigen presentation and B/T-cell function, (2) increased repurposed neutrophils and M1-type macrophages, (3) relatively immature or disrupted endothelia and fibroblasts with a defined secretome, and (4) reactive myeloid lines. Extracellular matrix changes identified in COVID-19 plasma could represent impaired immune cell homing and programmed cell death. The major functional modules disrupted in COVID-19 were exaggerated in patients with fatal outcome. Taken together, these findings provide systems-level insight into the mechanisms of COVID-19 inflammation and identify potential prognostic biomarkers. Therapeutic strategies could be tailored to the immune response of severely ill patients.     

Einiges vom Verhalten der Nebelkr?he(Corvus corone cornix)

Zusammenfassung Ein Strandwald bei Danzig diente im Winter Zehntausenden von Nebelkrähen als Schlafplatz. Jeden Morgen flogen die Krähen nach allen Richtungen zu ihren Nahrungsplätzen, die zum Teil 50 und mehr Kilometer entfernt waren. Es wird ein Fall geschildert, aus dem hervorgeht, wodurch die Entdeckung einer besonders ergiebigen Nahrungsquelle den Artgenossen in weitem Umkreis bekannt wird.Das Raubvogel-Schema der Krähen ist sehr weit und schließt nur den Seeadler aus, der (wenigstens im Winter) von ihnen nicht angegriffen, sondern als Nahrungsspender betrachtet wird. Besonders heftig reagieren sie auf den Habicht. 150–200 Nebelkrähen belagerten einen Habicht, der vor ihnen in ein Kiefernstangenholz geflüchtet war. Der Baummarder löst bei Nebelkrähen dieselbe starke Reaktion aus wie der Habicht. Kolkraben scheinen im Winter von Krähen nicht angegriffen zu werden.     

Studies on the catalytic mechanism of H2-forming methylenetetrahydromethanopterin dehydrogenase: para-ortho H2 conversion rates in H2O and D2O

H₂–forming N ⁵,N ¹⁰ –methylenetetrahydromethanopterin dehydrogenase is a novel type of hydrogenase that contains neither nickel nor iron-sulfur clusters. Evidence has been presented that the reaction mechanism catalyzed by the enzyme is very similar to that of the formation of carbocations and H₂ from alkanes under superacidic conditions. We present here further results in support of this mechanism. It was found that the purified enzyme per se did not catalyze the conversion of para H₂ to ortho H₂, a reaction catalyzed by all other hydrogenases known to date. However, it catalyzed the conversion in the presence of the substrate N ⁵,N ¹⁰ –methenyltetrahydromethanopterin (CH≡H₄MPT⁺), indicating that for heterolytic cleavage of H₂ the enzyme-CH≡H₄MPT⁺ complex is required. In D₂O, the formation of HD and D₂ from H₂ rather than a para–ortho H₂ conversion was observed, indicating that after heterolytic cleavage of H₂ the dissociation of the proton from the enzyme-substrate complex is fast relative to the re-formation of free H₂.     

Different roles of CheY1 and CheY2 in the chemotaxis of Rhizobium meliloti

Cells of Rhizobium meliloti swim by the unidirectional, clockwise rotation of their right-handed helical flagella and respond to tactic stimuli by modulating the flagellar rotary speed. We have shown that wild-type cells respond to the addition of proline, a strong chemoattractant, by a sustained increase in free-swimming speed (chemokinesis). We have examined the role of two response regulators, CheY1 and CheY2, and of CheA autokinase in the chemotaxis and chemokinesis of R. meliloti by comparing wild-type and mutant strains that carry deletions in the corresponding genes. Swarm tests, capillary assays, and computerized motion analysis revealed that (i) CheY2 alone mediates 60 to 70% of wild-type taxis, whereas CheY1 alone mediates no taxis, but is needed for the full tactic response; (ii) CheY2 is the main response regulator directing chemokinesis and smooth swimming in response to attractant, whereas CheY1 contributes little to chemokinesis, but interferes with smooth swimming; (iii) in a CheY2-overproducing strain, flagellar rotary speed increases upon addition and decreases upon removal of attractant; (iv) both CheY2 and CheY1 require phosphorylation by CheA for activity. We conclude that addition of attractant causes inhibition of CheA kinase and removal causes activation, and that consequent production of CheY1-P and CheY2-P acts to slow the flagellar motor. The action of the chief regulator, CheY2-P, on flagellar rotation is modulated by CheY1, probably by competition for phosphate from CheA.