The ₉₅RGD₉₇ sequence on the A alpha chain of fibrinogen is essential for binding to its erythrocyte receptor

Background: Erythrocyte aggregation, a cardiovascular risk factor, is increased by high plasma fibrinogen levels. Here, the effect of different fibrinogen mutations on binding to its human erythrocyte receptor was assessed in order to identify the interaction sites. Methods: Three fibrinogen variants were tested, specifically mutated in their putative integrin recognition sites on the Aα chain (mutants D97E, D574E and D97E/D574E) and compared with wild-type fibrinogen. Results: Atomic force microscopy-based force spectroscopy measurements showed a significant decrease both on the fibrinogen–erythrocyte binding force and on its frequency for fibrinogen with the D97E mutation, indicating that the corresponding arginine–glycine–aspartate sequence (residues 95–97) is involved in this interaction, and supporting that the fibrinogen receptor on erythrocytes has a β3 subunit. Changes in the fibrin clot network structure obtained with the D97E mutant were observed by scanning electron microscopy. Conclusion: These findings may lead to innovative perspectives on the development of new therapeutic approaches to overcome the risks of fibrinogen-driven erythrocyte hyperaggregation

RESPIRATORY ACTIVITY OF APICAL MERISTEMS OF PLAGIOTROPIC BRANCHES OF Araucaria angustifolia (Bertol.) Kuntze

Araucaria angustifolia apresenta redu\ue7\ue3o da taxa de crescimento durante o ano, podendo ser resposta \ue0s condi\ue7\uf5es ambientais desfavor\ue1veis, como ocorre nas fruteiras de clima temperado, que apresentam dorm\ueancia de gemas como forma de sobreviv\ueancia. O objetivo deste trabalho foi avaliar a din\ue2mica da atividade respirat\uf3ria de meristemas apicais de ramos plagiotr\uf3picos de Araucaria angustifolia. Foram coletadas amostras de 0,4 g de brota\ue7\uf5es terminais de ramos plagiotr\uf3picos de plantas jovens e adultas, as quais foram mantidas em 5 mL de solu\ue7\ue3o de cloreto de 2,3,5 trifeniltetraz\uf3lio (1,2%) em sala de crescimento a 25\ub0C. Em seguida, foram mantidas em 4 mL de \ue1lcool et\uedlico absoluto para leitura por espectrofotometria da absorb\ue2ncia a 560 nm. A atividade respirat\uf3ria de meristemas apicais de ramos plagiotr\uf3picos de Araucaria angustifolia \ue9 vari\ue1vel durante o ano. A maior atividade respirat\uf3ria ocorre na metade da primavera e a menor atividade respirat\uf3ria ocorre no inverno, em plantas jovens e adultas. Plantas adultas permanecem em alta atividade respirat\uf3ria por um per\uedodo maior, at\ue9 o in\uedcio do ver\ue3o.Araucaria angustifolia decreases its growth ratio during the fall and winter in response to adverse environmental conditions such as in temperate fruits where bud dormancy as a survival startegy. The aim of this study was to evaluate the dynamics of the respiratory activity of apical meristems of plagiotropic branches of Araucaria angustifolia. To determine the respiratory activity, samples with 0.4 g of apical buds of plagiotropic branches of young and adult plants were collected. These buds were maintained during two hours in 5 mL of 2,3,5-triphenyl tetrazolium chloride (1.2%) in a growth room at 25 \ub0C. Then, it was maintained during one hour in 4 mL of absolute ethyl alcohol and then the absorbance was determined by reading in spectrophotometer at 560 nm. The respiratory activity of apical meristems of plagiotropic branches of Araucaria angustifolia changed during the year, reducing in mid-spring and become lower in the winter in both young and adult plants. Adult plants remained with lower respiratory activity for a longer period, until the beginning of summer

Sensing adhesion forces between erythrocytes and γ’ fibrinogen, modulating fibrin clot architecture and function

Plasma fibrinogen includes an alternatively spliced γ-chain variant (γ’), which mainly exists as a heterodimer (γAγ’) and has been associated with thrombosis. We tested γAγ’ fibrinogen-red blood cells (RBCs) interaction using atomic force microscopy-based force spectroscopy, magnetic tweezers, fibrin clot permeability, scanning electron microscopy and laser scanning confocal microscopy. Data reveal higher work necessary for RBC-RBC detachment in the presence of γAγ’ rather than γAγA fibrinogen. γAγ’ fibrinogen–RBCs interaction is followed by changes in fibrin network structure, which forms an heterogeneous clot structure with areas of denser and highly branched fibrin fibers. The presence of RBCs also increased the stiffness of γAγ’ fibrin clots, which are less permeable and more resistant to lysis than γAγA clots. The modifications on clots promoted by RBCs-γAγ’ fibrinogen interaction could alter the risk of thrombotic disorders

Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura: Trichodactylidae) at La Plata basin

Background: In inland water systems, it is important to characterize the trophic links in order to identify the ‘trophic species’ and, from the studies of functional diversity, understand the dynamics of matter and energy in these environments. The aim of this study is to analyze the natural diet of Trichodactylus kensleyi of subtropical rainforest streams and corroborate the temporal variation in the trophic activity during day hours. Results: A total of 15 major taxonomic groups were recognized in gut contents. The index of relative importance identified the following main prey items in decreasing order of importance: vegetal remains, oligochaetes, chironomid larvae, and algae. A significant difference was found in the amount of full stomachs during day hours showing a less trophic activity at midday and afternoon. The index of relative importance values evidenced the consumption of different prey according to day moments. Results of the gut content indicate that T. kensleyi is an omnivorous crab like other trichodactylid species. Opportunistic behavior is revealed by the ingestion of organisms abundant in streams such as oligochaetes and chironomid larvae. The consumption of allochthonous plant debris shows the importance of this crab as shredder in subtropical streams. However, the effective assimilation of plant matter is yet unknown in trichodactylid crabs. Conclusions: This research provides knowledge that complements previous studies about trophic relationships of trichodactylid crabs and supported the importance of T. kensleyi in the transference of energy and matter from benthic community and riparian sources to superior trophic levels using both macro- and microfauna.Fil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: de Azevedo Carvalho, Debora. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentin

Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space

Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202

Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space

Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202

Analysis of the distortional buckling mode of perforated elements using the direct strength method.

Este trabalho apresenta um estudo te?rico e num?rico da influ?ncia de perfura??es no comportamento e capacidade resistente de pilares em perfis formados a frio submetidos a compress?o. Pilares com diferentes se??es transversais e perfura??es foram avaliados numericamente via ANSYS e GBTul, com ?nfase no modo de instabilidade distorcional. As for?as ?ltimas da an?lise num?rica foram comparadas ?s equa??es do M?todo da Resist?ncia Direta (MRD) da ABNT NBR 14762:2010. Finalmente, foram propostas adequa??es ?s equa??es do MRD para possibilitar o dimensionamento de pilares que apresentam se??es com a tipologia de perfura??es estudadas.This work presents a theoretical and numerical study on the influence of perforations on the behavior and strength of cold?formed steel columns subjected to compression. Members of different cross?sections and perforations were evaluated numerically via ANSYS and GBTul, with emphasis on distortional buckling mode. The ultimate loads of the numerical analysis were compared to the Direct Strength Method (DSM) equations of ABNT NBR 14762:2010. Finally, changes were proposed in the DSM equations so it is possible calculate the predicted compressive strengths of columns with perforated cross?sections studied