Effect of CO2 on elemental composition and fatty acids of diatoms and concomitant effects on copepods

Since the beginning of the industrial revolution the atmospheric partial pressure of CO2 (pCO2) has increased exponentially, reaching 380 μatm nowadays, and is expected to rise to values up to 700 μatm by the end of this century. These changes affect marine plankton in various ways, positively as for cyanobacteria, or in most cases, negatively as for coccolithophores. However there is a lack in the understanding of the effect of this increase in carbon for some important organisms as diatoms, an important primary producer in the ocean. Diatoms have not been reported as affected by ocean acidification, although several studies have reported a change of the total lipid content in some diatoms when cultured at high CO2 conditions. With this perspective, a set of two experiments were designed; the first was intended to determine if the amount of different fatty acids (the building blocks of lipids) of the diatom Thalassiosira pseudonana is altered when cultures under diverse CO2 conditions; while the second experiment was intended to determine the possible effects of the change in the fatty acids of T. pseudonana on the life cycle of the copepod Acartia tonsa when feed with this diatom. The first experiment showed that the fatty acid content of T. pseudonana change toward high CO2 levels, with an increase in the amount of saturated fatty acids and a decrease of unsaturated fatty acids content. The second experiment showed that the growth rate, amount of egg produced per female, and fatty acid content per female are reduced when feed with T. pseudonana cultured at high CO2 conditions. Our results show that CO2 actually affects the fatty acid composition of T. pseudonana and that this fatty acid alteration in the diatom have a significant influence on the life cycle of A. tonsa. However, further studies are required to determine if the effects observed in this study also take place in the environment

Primary producers and future ocean scenarios : effect of environmental change on biomolecular composition of phytoplankton and transference to higher trophic levels: effect of environmental change on biomolecular composition of phytoplankton and transference to higher trophic levels

An increasing body of research emphasizes that various biological processes in marine organisms are affected due to the uptake of anthropogenic atmospheric CO2 by the ocean in a process termed as ocean acidification (OA). The magnitude and direction of OA effects varies greatly among species and genotypes, highlighting different capabilities to adapt to increasing CO2. Direct OA impacts can be expected in the biochemical and elemental composition of primary producers (PP), which may be transferred to higher trophic levels, while indirect impacts can derive from altered trophic interactions as OA can modify plankton community composition. Fatty acids (FA) are the main component of lipids and cell membranes, with polyunsaturated fatty acids (PUFA) having additional important physiological and metabolic roles. Phytoplankton is the main source of essential biomolecules for heterotrophs as they cannot synthesize them de novo. Transference of organic essential macromolecules, in particular PUFA from phytoplankton-to-zooplankton-to-fish is a key factor influencing the life cycle of many organisms including humans. In the present work was investigated how OA influences the food quality of primary producers in terms of their fatty acid makeup at specie and community level, and how these OA-driven changes in the algae affect the fatty acid profile and life cycle of consumers. A combination of short- and long-term experiments on individual algal species, interaction between a single primary producer and one consumer, and natural plankton communities encompassing several producers and consumers were conducted in laboratory and natural conditions. In the short-term experiments at species level, the first and second laboratory study showed that CO2 can affect the biochemical composition of the diatoms Thalassiosira pseudonana and Cylindrotheca fusiformis, reducing their PUFA content; additionally the second diatom showed a reduced amount of amino acids. The interaction between a single primary producer and one consumer showed that when T. pseudonana cultured under high CO2 was used to feed the copepod Acartia tonsa, it affected their FA composition, severely impaired development and egg production rates. This demonstrated that a direct OA-driven shift in algal food quality can influence the reproduction success of upper trophic levels. At the community level, the third study conducted in a North Sea natural plankton assemblage subjected to a CO2 gradient showed that OA can modify phytoplankton community structures by favoring small phytoplankton cells with a comparatively low PUFA content. This community shift reduced PUFA content in primary producers was linked to a gradual PUFA decline in the dominant copepod species Calanus finmarchicus. In contrary, the fourth study revealed that the natural plankton community of the Baltic Sea experienced small differences in the algal community composition between CO2 treatments. The PUFA profile of the PP was influenced by phosphorus availability in the mesocosms, which was reflected by the PUFA composition of the copepod Acartia tonsa and Eurytemora affinis, but showed no significant CO2-related changes. This indicates that OA can affect the plankton community composition and its associated PUFA content, however this effect is lower in environments where communities are exposed to natural occurring high CO2 fluctuations like in the Baltic Sea, and that other essential nutrients have a stronger influence in the algal FA profile when present in limited amounts. In the long term experiments at species level, the fourth study determined that the coccolithophore Emiliania huxleyi and the diazotrophic cyanobacterium Trichodesmium sp. cultured over a thousand generations at high CO2 conditions showed a change in their FA content and composition. The FA profile of both algae presented a differentiate adaptation to high CO2 and particularly PUFA, which have metabolic functions in the cells, displayed evidence of adaptive evolution in both algae. These results highlight the diversity of OA responses among single plankton species and communities and that changes in biomolecular composition at the base of the marine food web are transferred to primary consumers. The thesis also highlights that the magnitude and direction of CO2-effects likely depends on the CO2 conditions and fluctuations the organisms are adapted to.Immer mehr wissenschaftliche Studien zeigen, dass Ozeanversauerung, das heißt die Aufnahme des anthropogenen CO2 aus der Atmosphäre in den Ozean, viele biologische Prozesse in marinen Organismen beeinflusst. Sowohl Stärke als auch Richtung dieser Ozeanversauerungseffekte können sehr variieren, je nach Arten und Genotypen, und zeigen damit unterschiedliche Anpassungsfähigkeiten an steigende CO2-Konzentrationen. Es wird erwartet, dass Ozeanversauerung sich direkt auf die Biochemie und Elementarzusammensetzung von Primärproduzenten auswirkt und diese Effekte auf höhere trophische Ebenen übertragen werden. Weiterhin könnte Ozeanversauerung indirekt trophische Interaktionen beeinflussen, indem sie die Zusammensetzung der Planktongemeinschaft verändert. Fettsäuren sind die Hauptbestandteile von Lipiden und Zellmembranen. Mehrfach ungesättigte Fettsäuren (engl. Polyunsaturated fatty acids, PUFA) spielen außerdem eine zentrale physiologische und metabolische Rolle. Phytoplankton ist die wichtigste Quelle essentieller Biomoleküle für heterotrophe Organismen, die diese selbst nicht de novo synthetisieren können. Der Transfer dieser essentiellen, organischen Makromoleküle, speziell PUFA, von Phytoplankton auf Zooplankton und Fische ist ein Schlüsselfaktor für den Lebenszyklus vieler Organismen, auch für den des Menschen. Diese Arbeit untersucht den Einfluss der Ozeanversauerung auf die Zusammensetzung und Nahrungsqualität der Primärproduzenten bezogen auf den Aufbau und Transfer von Fettsäuren in höhere trophische Ebenen. Hierfür wurden Kurz- und Langzeitexperimente durchgeführt mit einzelnen Algenarten (Studien I, II und V), zu Interaktion zwischen einem Primärproduzenten und einem Konsumenten (Studie II) sowie mit natürlichen Planktongemeinschaften bestehend aus zahlreichen Produzenten und Konsumenten (Studien II und IV). Die ersten beiden Kurzzeitexperimente im Labor zeigen, dass eine Erhöhung des CO2 die biochemische Zusammensetzung der beiden Diatomeen Thalassiosira pseudonana und Cylindrotheca fusiformis verändert und ihren PUFA-Gehalt reduziert. Außerdem verringer sich der Anteil an Aminosäuren in C. fusiformis. Thalassiosira pseudonana, die unter erhöhten CO2-Konzentrationen kultiviert wurden, wurden anschließend an den Ruderfußkrebs Arcatia tonsa verfüttert. Infolgedessen veränderte sich die Fettsäurezusammensetzung der Konsumenten, was Entwicklung und Eiproduktionsraten erheblich beeinträchtigte. Diese Ergebnisse zeigen, dass eine direkte Veränderung der Nahrungsqualität von Algen aufgrund von Ozeanversauerung den Fortpflanzungserfolg höherer trophischer Ebenen beeinflussen kann. In der dritten Studie wurde eine natürliche Planktongemeinschaft der Nordsee einem CO2-Gradienten ausgesetzt. Aufgrund der Versauerung setzten sich vor allem Phytoplankton-Arten mit kleinen Zellgrößen und vergleichsweise geringem PUFA-Gehalt durch. Gleichzeitig mit der PUFA-Abnahme in den Primärproduzenten verringerte sich auch sukzessive der PUFA-Gehalt der dominanten Ruderfußkrebsart Calanus finmarchicus. Im Gegensatz dazu wies die Ostsee-Planktongemeinschaft der vierten Studie nur kleine CO2-bedingte Änderungen in ihrer Zusammensetzung auf. Das PUFA-Profil der Primärproduzenten wurde durch die Phosphorverfügbarkeit in den Mesokosmen, aber nicht signifikant durch die CO2-Konzentration beeinflusst. Dies zeigte sich auch in der PUFA-Zusammensetzung der Ruderfußkrebse Acartia tonsa und Eurytemora affinis. Diese Ergebnisse deuten darauf hin, dass Ozeanversauerung die Zusammensetzung der Planktongemeinschaft und deren PUFA-Gehalt verändern kann. Gleichzeitig wird aber auch deutlich, dass dieser Effekt schwächer ist in Regionen wie der Ostsee, die natürlichen hohen CO2-Schwankungen unterliegen. Essentielle Nährstoffe scheinen weitaus bedeutender zu sein für die Fettsäurezusammensetzung von Algen, sobald sie limitierend sind. Während der fünften Studie, einem Langzeitexperiment, wurden die Kalkalge Emiliania huxleyi und die stickstofffixierende Blaualge Trichodesmium sp. über mehr als 1000 Generationen unter erhöhten CO2-Konzentrationen kultiviert. Beide reagierten mit einer Veränderung von Fettsäuregehalt und -zusammensetzung und zeigten eine klare Adaptation an die hohen CO2-Bedingungen. Besonders die Veränderungen der PUFA, die eine wichtige Rolle im Zellmetabolismus spielen, zeigten deutlich erkennbar die adaptive Evolution beider Algen. Die Ergebnisse dieser Arbeit belegen die Vielfältigkeit der Reaktionen von einzelnen Planktonarten und -gemeinschaften auf Ozeanversauerung. Jede Änderung der biomolekular Zusammensetzung an der Basis des marinen Nahrungsnetzes überträgt sich auf Primärkonsumenten. Weiterhin zeigt diese Dissertation auf, dass Stärke und Richtung der CO2-Effekte je nach Art und Gemeinschaft sehr unterschiedlich sind und wahrscheinlich davon abhängen, an welche CO2-Bedingungen und -schwankungen die Organismen angepasst sind

Regeneración de plantas via embriogénesis somática en Phaseolus acutifolius A. Gray

Plant regeneration protocols are a requirement to develop plants transformation systems.The capacity of Phaseolus acutifolius A. Gray to regenerate plants from embryogenic callus formation was investigated. Two explants were used to form calli on a culture medium containing thidiazuron and indole-3-acetic acid. The embryonic axes showed better capacity than cotyledons to form embryos. Solar light was the most favourable to develop the in vitro plants. The 32% of somatic embryos with complete germination was achieved. These results indicate that somatic embryos formation and their germination in Phaseolus acutifolius A. Gray depended on the explant, culture medium and illumination conditions. In vitro-germinated plantlets were established in the greenhouse.Key words: bean, callus formation, plant regeneration, tissue culturePara desarrollar un sistema de transformación genética un requisito fundamental es contar con un protocolo de regeneración de plantas. En el trabajo se investigó la capacidad de Phaseolus acutifolius para regenerar plantas a partir de callos con estructuras embriogénicas. Se utilizaron dos tipos de explantes para la formación de callos en un medio de cultivo que contenía thidiazuron y ácido indol-acético. Los ejes embrionarios mostraron una mejor capacidad que los cotiledones para la formación de embriones somáticos. La luz solar resultó ser la más favorable para el desarrollo de las plantas in vitro. En estas condiciones se alcanzó el 32% de los embriones somáticos con germinación completa. Estos resultados indicanron que la formación de embriones somáticos y su germinación en Phaseolus acutifolius dependieron del explante, el medio de cultivo y las condiciones de iluminación. Las plantas germinadas in vitro, pudieron ser aclimatizadas en el invernadero.Palabras clave: cultivo de tejidos, formación de callos, frijol, regeneración de plantasAbbreviations: BAP 6- Benzylaminopurine, TDZ Thidiazuron, IAA indole-3-acetic acid, GA3 gibberellic acid, AgNO3 silver nitrat

Genotyping squamous cell lung carcinoma in Colombia (Geno1.1-CLICaP)

Background: Lung cancer is a public health problem, and squamous cell carcinoma (SCC) is the second most prevalent subtype of this neoplasm. Compared to other subtypes, including adenocarcinoma, SCC is less well understood in terms of molecular pathogenesis, limiting therapeutic options among targeted agents approved for other disease subgroups. In this study, we sought to characterize the SCC genomic profile using a validated Next Generation Sequencing (NGS) platform. Methods: The comprehensive NGS assay (TruSight Tumor 170) was used in order to target the full coding regions of 170 cancer-related genes on SCC samples. PD-L1 expression in tumor cells (TCs) was assessed using clone 22C3 (Dako). Clinical outcomes were correlated with molecular profile, including progression free survival (PFS), overall response rate (ORR), and overall survival (OS). Results: A total of 26 samples were included, median age was 67 years (r, 33–83) and 53.8% were men. Tobacco consumption was identified in all subjects (mean 34-year package). For first-line treatment 80.8% of patients received cisplatin or carboplatin plus gemcitabine. In terms of molecular profile, we identified a high prevalence of inactivating mutations in TP53 (61.5%), PIK3CA (34.6%), MLL2 (34.6%), KEAP1 (38.4%), and NOTCH1 (26.9%). PD-L1 expression ranged from negative, 1, 2–49, and ≥50% in 23.1, 38.5, 26.9, and 11.5%, respectively. Interestingly, the genetic alterations did not have an effect in PFS, OS or ORR in this study. However, PDL1 expression was higher among those who had mutations in TP53 (p = 0.037) and greater expression of PDL1 was related to PIK3CA alterations (p = 0.05). Conclusions: The genomic profile of SCC encompasses important genes including TP53, PIK3CA and KEAP1. TP53 mutations could be associated with PDL1 expression, generating hypothesis regarding specific treatment options

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe