Photoinactivation of phage phi6 as a SARS-CoV-2 model in wastewater: evidence of efficacy and safety

The last two years have been marked by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. This virus is found in the intestinal tract; it reaches wastewater systems and, consequently, the natural receiving water bodies. As such, inefficiently treated wastewater (WW) can be a means of contamination. The currently used methods for the disinfection of WW can lead to the formation of toxic compounds and can be expensive or inefficient. As such, new and alternative approaches must be considered, namely, photodynamic inactivation (PDI). In this work, the bacteriophage ϕ6 (or, simply, phage ϕ6), which has been used as a suitable model for enveloped RNA viruses, such as coronaviruses (CoVs), was used as a model of SARS-CoV-2. Firstly, to understand the virus’s survival in the environment, phage ϕ6 was subjected to different laboratory-controlled environmental conditions (temperature, pH, salinity, and solar and UV-B irradiation), and its persistence over time was assessed. Second, to assess the efficiency of PDI towards the virus, assays were performed in both phosphate-buffered saline (PBS), a commonly used aqueous matrix, and a secondarily treated WW (a real WW matrix). Third, as WW is generally discharged into the marine environment after treatment, the safety of PDI-treated WW was assessed through the determination of the viability of native marine water microorganisms after their contact with the PDI-treated effluent. Overall, the results showed that, when used as a surrogate for SARS-CoV-2, phage ϕ6 remains viable in different environmental conditions for a considerable period. Moreover, PDI proved to be an efficient approach in the inactivation of the viruses, and the PDI-treated effluent showed no toxicity to native aquatic microorganisms under realistic dilution conditions, thus endorsing PDI as an efficient and safe tertiary WW disinfection method. Although all studies were performed with phage ϕ6, which is considered a suitable model of SARS-CoV-2, further studies using SARS-CoV-2 are necessary; nevertheless, the findings show the potential of PDI for controlling SARS-CoV-2 in WW.info:eu-repo/semantics/publishedVersio

Photodynamic inactivation of phage Phi6 as SARS-CoV-2 model in wastewater disinfection: effectivity and safety

The past 2 years have been marked by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. This virus is found in the intestinal tract and reaches the wastewater system, and, consequently, the natural receiving water bodies, and inappropriate or/and inefficient WW treatment is a means of contamination. In the present work, we used a SARS-CoV-2 model—the phage Phi6—to evaluate its survival under different environmental conditions (pH, temperature, salinity, solar, and UV-B irradiation). Then, we tested the efficiency of photodynamic inactivation (PDI) as a WW disinfection alternative method, and, additionally, the impact on the cultivable native marine microorganisms of the PDI-treated WW was evaluated.info:eu-repo/semantics/publishedVersio

Bioprocess integration for human mesenchymal stem cells: from up to downstream processing scale-up to cell proteome characterization

Human mesenchymal stem cells (hMSC) are relevant cell-based products for autologous and allogeneic therapies. To deliver the required cell numbers and doses to therapy, scaling up production and purification processes (at least to the liter-scale) while ensuring high purity, viability and maintaining cells’ critical quality attributes (CQA) and functionality is essential [1]. Therefore, the aim of this work was to prove scalability of an integrated streamlined bioprocess compatible with current good manufacturing practices (cGMP) comprised by cell expansion, harvesting and volume reduction unit operations using human mesenchymal stem cells (hMSC) isolated from bone marrow (BM-MSC) and adipose tissues (AT-MSC). BM-MSC and AT-MSC expansion and harvesting steps were scaled-up from spinner flasks to 2 L scale stirred tank single-use bioreactor using synthetic microcarriers and xeno-free medium, ensuring high cellular volumetric productivities (50 x 106 cell.L-1.day-1), expansion factors (14 - 16 fold) and cell recovery yields (80%). For the concentration step, flat sheet cassettes (FSC) and hollow fiber cartridges (HF) were compared showing a fairly linear scale-up, with a need to slightly decrease the permeate flux (30 - 50 LMH, respectively) to maximize cell recovery yield. Nonetheless, FSC allowed to recover 18% more cells after a volume reduction factor of 50. Overall, at the end of the entire bioprocess more than 65% of viable (\u3e 95%) hMSC could be recovered without compromising cell’s CQA of viability, identity and differentiation potential. “Omic” tools in combination with standard analytical assays allow for a better cell characterization, increasing product and process understanding [2] and are thus fundamental for process development. Thus, alongside the standard quality assays for evaluating hMSC’s CQA, a proteomics workflow based on mass spectrometry tools was established to characterize the impact of processing on hMSC’ CQA. Overall, through sensitivity, robustness and throughput, this type of workflow provided the identification of specific signatures of the final product. Therefore, it proves to be essential to understand the cells’ final quality as well as to evaluate the impact of manufacturing at different stages of processing. References: [1] Pattasseril J et al, BioProcess Int. 2013, 3, 38–46. [2] Campbell A et al, Stem Cells Transl. Med. 2015, 4, 1155–1163. The authors acknowledge UniMS – Mass Spectrometry Unit team (ITQB-NOVA/iBET, Oeiras, Portugal), iNOVA4Health Research Unit (LISBOA-01-0145-FEDER-007344), and Fundação para a Ciência e Tecnologia (FCT, Portugal) for funding the project CARDIOSTEM (MITP-TB/ECE/0013/2013), and the grants SFRH/BD/51940/2012 (MIT-Portugal), SFRH/BD/52302/2013, SFRH/BD/52481/2014, SFRH/BPD/86513/201

Engineering scalable manufacturing of high-quality human MSC for cell therapy: From up to downstream processing integration to cell proteome characterization

Human mesenchymal stem cells (hMSC) are relevant cell therapy products for autologous and allogeneic therapies. To deliver the required cell numbers and doses to therapy, scaling up production and purification processes (at least to the liter-scale) while ensuring high purity, viability and maintaining cells’ critical quality attributes (CQA) and functionality is essential. Therefore, the aim of this work was to prove scalability of an integrated streamlined bioprocess compatible with current good manufacturing practices (cGMP) comprised by cell expansion, harvesting, volume reduction and washing unit operations using human mesenchymal stem cells (hMSC) isolated from bone marrow (BM-MSC) and adipose tissues (AT-MSC). Single-use technologies were adopted at different steps of the manufacturing workflow to support process integration and scale-up. BM-MSC and AT-MSC expansion and harvesting steps were scaled-up from spinner flasks to 2 L single-use stirred tank bioreactor using synthetic microcarriers and xeno-free medium, ensuring high cellular volumetric productivities (50 x 106 cell.L-1.day-1), expansion factors (14 - 16 fold) and cell recovery yields (\u3e80%). For the volume reduction and washing steps, flat sheet cassettes (FSC) and hollow fiber cartridges (HF) were compared showing a fairly linear scale-up, with a need to slightly decrease the permeate flux (30 - 50 LMH, respectively) to maximize cell recovery yield. Nonetheless, FSC performed better allowing recovering 18% more cells after a volume reduction factor of 50 without compromising cell’s CQA of viability, identity and differentiation potential. “Omic” tools in combination with standard analytical assays allow for a better cell characterization, increasing product and process understanding and are thus fundamental for process development. Thus, alongside the standard quality assays for evaluating hMSC’s CQA, a proteomics workflow based on mass spectrometry tools was established to characterize the impact of processing on hMSC’ CQA. Overall, through sensitivity, robustness and throughput, this type of workflow provided the identification of specific signatures of the final product. Therefore, it proves to be essential to understand the cells’ final quality as well as to evaluate the impact of manufacturing at different stages of processing. The authors acknowledge UniMS – Mass Spectrometry Unit team (ITQB-NOVA/iBET, Oeiras, Portugal), iNOVA4Health Research Unit (LISBOA-01-0145-FEDER-007344), and Fundação para a Ciência e Tecnologia (FCT, Portugal) for funding the project CARDIOSTEM (MITP-TB/ECE/0013/2013), and the grants SFRH/BD/51940/2012 (MIT-Portugal), SFRH/BD/52302/2013, SFRH/BD/52481/2014, SFRH/BPD/86513/2012

The CO2 record at the Amazon Tall Tower Observatory : A new opportunity to study processes on seasonal and inter-annual scales

High-quality atmospheric CO2 measurements are sparse in Amazonia, but can provide critical insights into the spatial and temporal variability of sources and sinks of CO2. In this study, we present the first 6 years (2014-2019) of continuous, high-precision measurements of atmospheric CO2 at the Amazon Tall Tower Observatory (ATTO, 2.1 degrees S, 58.9 degrees W). After subtracting the simulated background concentrations from our observational record, we define a CO2 regional signal (Delta CO2obs) that has a marked seasonal cycle with an amplitude of about 4 ppm. At both seasonal and inter-annual scales, we find differences in phase between Delta CO2obs and the local eddy covariance net ecosystem exchange (EC-NEE), which is interpreted as an indicator of a decoupling between local and non-local drivers of Delta CO2obs. In addition, we present how the 2015-2016 El Nino-induced drought was captured by our atmospheric record as a positive 2 sigma anomaly in both the wet and dry season of 2016. Furthermore, we analyzed the observed seasonal cycle and inter-annual variability of Delta CO2obs together with net ecosystem exchange (NEE) using a suite of modeled flux products representing biospheric and aquatic CO2 exchange. We use both non-optimized and optimized (i.e., resulting from atmospheric inverse modeling) NEE fluxes as input in an atmospheric transport model (STILT). The observed shape and amplitude of the seasonal cycle was captured neither by the simulations using the optimized fluxes nor by those using the diagnostic Vegetation and Photosynthesis Respiration Model (VPRM). We show that including the contribution of CO2 from river evasion improves the simulated shape (not the magnitude) of the seasonal cycle when using a data-driven non-optimized NEE product (FLUXCOM). The simulated contribution from river evasion was found to be 25% of the seasonal cycle amplitude. Our study demonstrates the importance of the ATTO record to better understand the Amazon carbon cycle at various spatial and temporal scales.Peer reviewe