A quantitative assessment of site-level factors in influencing Chukar (Alectoris chukar) introduction outcomes.

Chukar partridges (Alectoris chukar) are popular game birds that have been introduced throughout the world. Propagules of varying magnitudes have been used to try and establish populations into novel locations, though the relationship between propagule size and species establishment remains speculative. Previous qualitative studies argue that site-level factors are of importance when determining where to release Chukar. We utilized machine learning ensembles to evaluate bioclimatic and topographic data from native and naturalized regions to produce predictive species distribution models (SDMs) and evaluate the relationship between establishment and site-level factors for the conterminous United States. Predictions were then compared to a distribution map based on recorded occurrences to determine model prediction performance. SDM predictions scored an average of 88% accuracy and suitability favored states where Chukars were successfully introduced and are present. Our study shows that the use of quantitative models in evaluating environmental variables and that site-level factors are strong indicators of habitat suitability and species establishment.

Use of Biosimilar Granulocyte Colony-Stimulating Factor for Mobilization in Autologous and Allogeneic Hematopoietic Stem Cell Transplantation.

The biologic medication filgrastim is approved by the Food and Drug Administration (FDA) to mobilize hematopoietic progenitor cells (HPCs) for collection by leukapheresis for autologous hematopoietic stem cell transplant (HSCT). The FDA-approved biologic tbo-filgrastim is currently used off-label for this indication in both autologous and allogeneic HSCT at the Tennessee Valley Healthcare System. The purpose of this review is to compare the efficacy of filgrastim and tbo-filgrastim for this indication. The primary outcomes were the proportion of autologous patients and allogeneic donors with a CD34+ count ≥15 × 103 cells/uL on day 4 of filgrastim or tbo-filgrastim mobilization. The secondary outcome was the use of plerixafor in the autologous population. A total of 469 subjects were identified for inclusion; 367 underwent mobilization for autologous HSCT and 102 for allogeneic HSCT donation. The primary outcome was achieved in 47.5% of patients who received filgrastim compared to 50.2% who received tbo-filgrastim in the autologous population (p = 0.67). Among donors for allogeneic HSCT, there was no difference between those eligible for collection on day 4 of filgrastim or tbo-filgrastim administration (97.6% vs. 100%, p = 0.41). No significant difference was identified in the number of patients requiring plerixafor use in the autologous HSCT population. The use of the biosimilar tbo-filgrastim for mobilization in either autologous HSCT patients or allogeneic HSCT donors has comparable outcomes to that of the biotherapeutic reference product filgrastim at a reduced cost to the healthcare system.

"Living" dynamics of filamentous bacteria on an adherent surface under hydrodynamic exposure.

The potential advantages of cell-based biohybrid devices over conventional nonliving systems drive the interest to control the behavior of the underlying biological cells in microdevices. Here, the authors studied how shear influenced the geometry and elongation of fimbriated filaments on affinity substrates. The cells were engineered to express FimH, which binds to mannose with a high affinity. A microfluidic channel was functionalized with RNAse B, which is rich in mannose residues, and the device was used to control the hydrodynamic force on live Escherichia coli under filamentous growth. It was discovered that filamentous E. coli cells adopt buckled geometry when the shear rate is low, but assume an extended geometry at high shear and align with the flow direction. The extension moves from bidirectional to preferentially downstream as the shear rate increases. Furthermore, living filaments slide easily on the substrate, and detach from the substrates at a rate nearly ten times greater than unfilamented live E. coli at high shear conditions (1000-4000 s-1). The hydrodynamic force and binding force experienced by the cells are further analyzed by COMSOL simulation and atomic force microscopy measurements, respectively, to explore the mechanism behind the living cell dynamics. Knowledge from this work helps guide design of interfacial properties and shear environments to control the geometry of living filamentous bacteria.

Influences of Adhesion Variability on the "Living" Dynamics of Filamentous Bacteria in Microfluidic Channels.

Microfabricated devices have increasingly incorporated bacterial cells for microscale studies and exploiting cell-based functions in situ. However, the role of surface interactions in controlling the bacterial cell behavior is not well understood. In this study, microfluidic substrates of varied bacterial-binding affinity were used to probe the interaction-driven behavior of filamentous Escherichia coli. In particular, cell alignment under controlled shear flow as well as subsequent orientation and filamentation were compared between cells presenting distinct outer membrane phenotypes. We demonstrated that filaments retained position under flow, which allowed for dynamic single-cell monitoring with in situ elongation of over 100 µm for adherent cells. This maximum was not reached by planktonic cells and was, therefore, adhesion-dependent. The bound filaments initially aligned with flow under a range of flow rates and their continual elongation was traced in terms of length and growth path; analysis demonstrated that fimbriae-mediated adhesion increased growth rate, increased terminal length, as well as dramatically changed the adherent geometry, particularly buckling behavior. The effects to filament length and buckling were further exaggerated by the strongest, specificity-driven adhesion tested. Such surface-guided control of the elongation process may be valuable to yield interesting "living" filamentous structures in microdevices. In addition, this work may offer a biomedically relevant platform for further elucidation of filamentation as an immune-resistant morphology. Overall, this work should inspire broader exploration of microfabricated devices for the study and application of single bacterial cells.