Biology subjects

Giardina, F.

Publications and source records attributed to Giardina, F..

4 recordsLinked to original sources

bioRxiv2021

Cooperative escape in ants and robots

The solution of complex problems by the collective action of simple agents in both biologically evolved and synthetically engineered systems involves cooperative action. Understanding the resulting emergent solutions requires integrating across the organismal behaviors of many individuals. Here we investigate an ecologically relevant collective task in black carpenter ants Camponotus pennsylvanicus: escape from a soft, erodible confining corral. Individual ants show a transition from individual exploratory excavation at random locations to spatially localized collective exploitative excavation and escape from the corral. A minimal continuum theory that coarse-grains over individual actions and considers their integrated influence on the environment leads to the emergence of an effective phase space of behaviors in terms of excavation strength and cooperation intensity. To test the theory over the range of predicted behaviors, we used custom-built robots (RAnts) that respond to stimuli and show the emergence (and failure) of cooperative excavation and escape. Overall, our approach shows how the cooperative completion of tasks can arise from relatively simple rules that involve the interaction of simple agents with a dynamically changing environment that serves as an enabler and modulator of behavior.

animal behavior and cognition↗

bioRxiv2021

Bispecific antibody prevents SARS-CoV-2 escape and protects mice from disease

Neutralizing antibodies targeting the receptor binding domain (RBD) of the SARS-CoV-2 Spike (S) are among the most promising approaches against coronavirus disease 2019 (COVID-19)1,2. We developed a bispecific, IgG1-like molecule (CoV-X2) based on two antibodies derived from COVID-19 convalescent donors, C121 and C1353. CoV-X2 simultaneously binds two independent sites on the RBD and, unlike its parental antibodies, prevents detectable S binding to Angiotensin-Converting Enzyme 2 (ACE2), the virus cellular receptor. Furthermore, CoV-X2 neutralizes SARS-CoV-2 and its variants of concern, as well as the escape mutants generated by the parental monoclonals. In a novel animal model of SARS-CoV-2 infection with lung inflammation, CoV-X2 protects mice from disease and suppresses viral escape. Thus, simultaneous targeting of non-overlapping RBD epitopes by IgG-like bispecific antibodies is feasible and effective, combining into a single molecule the advantages of antibody cocktails.

immunology↗

bioRxiv2020

Performance assessment of Respiratory Viral ELITe MGB(R) assay for the quantitative detection of influenza A/B and respiratory syncytial viruses

Influenza (Flu) and respiratory syncytial virus (RSV) are responsible for lower respiratory tract infections (LRTIs) associated with significant hospitalization among young children. In the present study, the performances of a triplex PCR assay detecting Flu A/B and RSV were compared with our in-house single-plex assays using 160 stored respiratory specimens previously tested using a panel of laboratory-developed real-time RT-PCR. Of them, 61 were positive for FluA, 41 for FluB, and 58 for RSV. All samples were retrospectively quantified with Respiratory Viral (RV) ELITe MGB(R) Panel (ELITechGroup Molecular Diagnostics, Puteaux, France) processed using ELITe InGenius(R) system. Overall, the total percentage agreement observed was 93.4% (57/61) for FluA, 92.7% (38/41) for FluB, and 86.2% (50/58) for RSV. A significant correlation of VL values was observed between the two methods for FluA and RSV ({rho}= 0.91 and 0.84). This finding was supported by the strength of agreement between the two methods, as showed by the linear regression analysis (R2 =0.84 and 0.80). FluB viral load values measured by RV Panel were less significantly correlated ({rho}= 0.77 and R2 =0.56). The bland-Altman analysis showed how 84.2% (48/57) of FluA and 86.0% of RSV (43/50) samples fell within {+/-}1.0 Log10 variation from our laboratory results, while only 21.1% (8/38) of FluB results fell within this range. The great majority of FluB samples (29/30) outside range had values higher than +1.0 Log10 (median +2.1 Log10 range +1.0 to +3.5 Log10). In conclusion, RV ELITe MGB(R) Panel constitutes a valid and robust system for simultaneous detection and quantification of Flu A/B and RSV.

microbiology↗

bioRxiv2018

Getting more from heterogeneous HIV-1 surveillance data in a high immigration country: estimation of incidence and undiagnosed population size using multiple biomarkers

BackgroundMost HIV infections originate from individuals who are undiagnosed and unaware of their infection. Estimation of this quantity from surveillance data is hard because there is incomplete knowledge about i) the time between infection and diagnosis (TI) for the general population and ii) the time between immigration and diagnosis for foreign-born persons.\n\nDevelopmentWe developed a new statistical method for estimating the number of undiagnosed people living with HIV (PLHIV) and the incidence of HIV-1 based on dynamic modeling of heterogenous HIV-1 surveillance data. We formulated a Bayesian non-linear mixed effects model using multiple biomarkers to estimate TI accounting for biomarker correlation and individual heterogeneities. We explicitly model the probability that an HIV-1 infected foreign-born person was infected either before or after immigration to distinguish between endogenous and exogeneous incidence. The incidence estimator allows for direct calculation of the number of undiagnosed persons.\n\nApplicationThe model was applied to surveillance data in Sweden. The dynamic biomarker model was trained on longitudinal data from 31 treatment-naive patients with well-defined TI, using CD4 counts, BED serology, polymorphisms in HIV-1 pol sequences, and testing history. The multiple-biomarker model was more accurate than single biomarkers (mean absolute error 1.01 vs [≥] 1.95). We estimate that 813 (95% CI 780-862) PLHIV were undiagnosed in 2015, representing a proportion of 10.8% (95% CI 10.4-11.3%) of all PLHIV.\n\nConclusionsThe proposed methodology will enhance the utility of standard surveillance data streams and will be useful to monitor progress towards and compliance with the 90-90-90 UNAIDS target.\n\nKey messagesO_LICombined heterogeneous HIV-1 surveillance data and biomarker data can be used to estimate both local incidence and the number of undiagnosed people living with HIV.\nC_LIO_LIExplicit modeling of the dynamics, heterogeneity, and correlation of multiple biomarkers over time improved estimation of time between infection and diagnosis.\nC_LIO_LIExplicit modeling of the probability that foreign-born persons were infected before or after immigration improves accuracy of estimates of endogenous incidence and undiagnosed persons living with HIV.\nC_LIO_LIThe endogenous incidence of HIV-1 in Sweden is declining, despite continued immigration of HIV-1 infected persons.\nC_LIO_LIThe proportion of undiagnosed PLHIV decreased over 2010-2015 and was estimated to be 10.8% (95% CI, 10.4-11.3%) in 2015.\nC_LI

epidemiology↗