New insights in bacillus subtillis levansucrase mechanism and applications

B. subtilis levansucrase (SacB) is a widely studied glycoside hydrolase from Family 68 family. Although reports on SacB properties date back to the 70’s (Chambert & Gonzy-Tréboul, 1976), questions regarding levan synthesis mechanism are still open. These questions refer to the factors influencing reaction specificity, including the effect of sucrose and levan hydrolysis, product structure and levan molecular weight. In this conference we review recent findings regarding the modulating effect of SacB concentration on levan molecular weight distribution (Porras-Domínguez et al., 2015; Raga-Carbajal et al., 2016). In effect, we demonstrated that high enzyme concentrations (\u3e1.0 µM), direct levan synthesis exclusively to low molecular weight products (av 7.6 KDa), while low enzyme concentrations (\u3c 0.1µM) favor the synthesis of a high molecular weight levan fraction (\u3e2000 kDa). From a detailed HPAEC-PAD analysis of product evolution, a shift from a clear non-processive elongation mechanism at high protein concentrations to a -most likely- processive mechanism when low protein concentrations are used in the reaction. Trough calorimetric experiments we demonstrate that these changes in enzyme performance do not involve protein-protein interactions (Raga-Carbajal et al., 2016). We demonstrated, through an extensive characterization of the levan hydrolysis reaction by SacB, that the wide diversity of products derives also from fructosyl transfer to free sugars available from sucrose and levan hydrolysis. Actually, levan is an efficient fructosyl donor for fructosylation reactions, in which FOS such as levanbiose, inulobiose, blastose, …, are formed (Méndez-Lorenzo et al., 2015). The efficiency of SacB fructosylation with levan as donor was applied for the synthesis of blastose, a sucrose analogue with potential prebiotic properties. For this reaction, fructose was transferred to trehalose to produce a (2-6) fructosylated trehalose, which was later hydrolysed by trehalase to yield blastose (Miranda-Molina et al, 2017). Up to now there is not an efficient enzyme for the synthesis of levan-type FOS, in spite of intensive efforts to modify SacB or other levansucrases specificity by site directed mutagenesis. For this purpose, after a complete characterization of a combined bi-enzymatic reaction between SacB and an endolevanase produced by B.licheniformis. (LevB1) (Porras-Domínguez et al., 2014) we designed a fusion enzyme containing both activities. This fusion enzyme is able to produce levan-type FOS from sucrose, with molecular weights in the range of DP2 to DP10 including mainly 1-kestose, 6-kestose, neokestose, levanbiose and blastose, with 40% w/w yields. Chambert, R., & Gonzy-Tréboul, G. (1976). European Journal of Biochemistry / FEBS, 62(1), 55–64. Méndez-Lorenzo, L., Porras-Domínguez, J. R., Raga-Carbajal, E., Olvera, C., Rodríguez-Alegría, M. E., Carrillo-Nava, E.. López Munguía, A. (2015). PLoS ONE, 10(11), 1–15. Miranda-Molina, A., Castillo, E., & Lopez Munguia, A. (2017). Food Chemistry, 227, 202–210. Porras-Domínguez, J. R., Ávila-Fernández, Á., Miranda-Molina, A., Rodríguez-Alegría, M. E., & Munguía, A. L. (2015). Carbohydrate Polymers, 132(October), 338–344. Porras-Domínguez, J. R., Ávila-Fernández, Á., Rodríguez-Alegría, M. E., Miranda-Molina, A., Escalante, A., González-Cervantes, R., López Munguía, A. (2014). Process Biochemistry, 49(5), 783–790. Raga-Carbajal, E., Carrillo-Nava, E., Costas, M., Porras-Dominguez, J., López-Munguía, A., & Olvera, C. (2016). Glycobiology, 26(4), 377–385

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

The European Reference Genome Atlas: piloting a decentralised approach to equitable biodiversity genomics

A global genome database of all of Earth’s species diversity could be a treasure trove of scientific discoveries. However, regardless of the major advances in genome sequencing technologies, only a tiny fraction of species have genomic information available. To contribute to a more complete planetary genomic database, scientists and institutions across the world have united under the Earth BioGenome Project (EBP), which plans to sequence and assemble high-quality reference genomes for all ∼1.5 million recognized eukaryotic species through a stepwise phased approach. As the initiative transitions into Phase II, where 150,000 species are to be sequenced in just four years, worldwide participation in the project will be fundamental to success. As the European node of the EBP, the European Reference Genome Atlas (ERGA) seeks to implement a new decentralised, accessible, equitable and inclusive model for producing high-quality reference genomes, which will inform EBP as it scales. To embark on this mission, ERGA launched a Pilot Project to establish a network across Europe to develop and test the first infrastructure of its kind for the coordinated and distributed reference genome production on 98 European eukaryotic species from sample providers across 33 European countries. Here we outline the process and challenges faced during the development of a pilot infrastructure for the production of reference genome resources, and explore the effectiveness of this approach in terms of high-quality reference genome production, considering also equity and inclusion. The outcomes and lessons learned during this pilot provide a solid foundation for ERGA while offering key learnings to other transnational and national genomic resource projects

Reduction of cardiac imaging tests during the COVID-19 pandemic: The case of Italy. Findings from the IAEA Non-invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Background: In early 2020, COVID-19 massively hit Italy, earlier and harder than any other European country. This caused a series of strict containment measures, aimed at blocking the spread of the pandemic. Healthcare delivery was also affected when resources were diverted towards care of COVID-19 patients, including intensive care wards. Aim of the study: The aim is assessing the impact of COVID-19 on cardiac imaging in Italy, compare to the Rest of Europe (RoE) and the World (RoW). Methods: A global survey was conducted in May–June 2020 worldwide, through a questionnaire distributed online. The survey covered three periods: March and April 2020, and March 2019. Data from 52 Italian centres, a subset of the 909 participating centres from 108 countries, were analyzed. Results: In Italy, volumes decreased by 67% in March 2020, compared to March 2019, as opposed to a significantly lower decrease (p &lt; 0.001) in RoE and RoW (41% and 40%, respectively). A further decrease from March 2020 to April 2020 summed up to 76% for the North, 77% for the Centre and 86% for the South. When compared to the RoE and RoW, this further decrease from March 2020 to April 2020 in Italy was significantly less (p = 0.005), most likely reflecting the earlier effects of the containment measures in Italy, taken earlier than anywhere else in the West. Conclusions: The COVID-19 pandemic massively hit Italy and caused a disruption of healthcare services, including cardiac imaging studies. This raises concern about the medium- and long-term consequences for the high number of patients who were denied timely diagnoses and the subsequent lifesaving therapies and procedures

Impact of COVID-19 on Diagnostic Cardiac Procedural Volume in Oceania: The IAEA Non-Invasive Cardiology Protocol Survey on COVID-19 (INCAPS COVID)

Objectives: The INCAPS COVID Oceania study aimed to assess the impact caused by the COVID-19 pandemic on cardiac procedure volume provided in the Oceania region. Methods: A retrospective survey was performed comparing procedure volumes within March 2019 (pre-COVID-19) with April 2020 (during first wave of COVID-19 pandemic). Sixty-three (63) health care facilities within Oceania that perform cardiac diagnostic procedures were surveyed, including a mixture of metropolitan and regional, hospital and outpatient, public and private sites, and 846 facilities outside of Oceania. The percentage change in procedure volume was measured between March 2019 and April 2020, compared by test type and by facility. Results: In Oceania, the total cardiac diagnostic procedure volume was reduced by 52.2% from March 2019 to April 2020, compared to a reduction of 75.9% seen in the rest of the world (p&lt;0.001). Within Oceania sites, this reduction varied significantly between procedure types, but not between types of health care facility. All procedure types (other than stress cardiac magnetic resonance [CMR] and positron emission tomography [PET]) saw significant reductions in volume over this time period (p&lt;0.001). In Oceania, transthoracic echocardiography (TTE) decreased by 51.6%, transoesophageal echocardiography (TOE) by 74.0%, and stress tests by 65% overall, which was more pronounced for stress electrocardiograph (ECG) (81.8%) and stress echocardiography (76.7%) compared to stress single-photon emission computerised tomography (SPECT) (44.3%). Invasive coronary angiography decreased by 36.7% in Oceania. Conclusion: A significant reduction in cardiac diagnostic procedure volume was seen across all facility types in Oceania and was likely a function of recommendations from cardiac societies and directives from government to minimise spread of COVID-19 amongst patients and staff. Longer term evaluation is important to assess for negative patient outcomes which may relate to deferral of usual models of care within cardiology

International Impact of COVID-19 on the Diagnosis of Heart Disease

Background: The coronavirus disease 2019 (COVID-19) pandemic has adversely affected diagnosis and treatment of noncommunicable diseases. Its effects on delivery of diagnostic care for cardiovascular disease, which remains the leading cause of death worldwide, have not been quantified. Objectives: The study sought to assess COVID-19's impact on global cardiovascular diagnostic procedural volumes and safety practices. Methods: The International Atomic Energy Agency conducted a worldwide survey assessing alterations in cardiovascular procedure volumes and safety practices resulting from COVID-19. Noninvasive and invasive cardiac testing volumes were obtained from participating sites for March and April 2020 and compared with those from March 2019. Availability of personal protective equipment and pandemic-related testing practice changes were ascertained. Results: Surveys were submitted from 909 inpatient and outpatient centers performing cardiac diagnostic procedures, in 108 countries. Procedure volumes decreased 42% from March 2019 to March 2020, and 64% from March 2019 to April 2020. Transthoracic echocardiography decreased by 59%, transesophageal echocardiography 76%, and stress tests 78%, which varied between stress modalities. Coronary angiography (invasive or computed tomography) decreased 55% (p &lt; 0.001 for each procedure). In multivariable regression, significantly greater reduction in procedures occurred for centers in countries with lower gross domestic product. Location in a low-income and lower–middle-income country was associated with an additional 22% reduction in cardiac procedures and less availability of personal protective equipment and telehealth. Conclusions: COVID-19 was associated with a significant and abrupt reduction in cardiovascular diagnostic testing across the globe, especially affecting the world's economically challenged. Further study of cardiovascular outcomes and COVID-19–related changes in care delivery is warranted