Biology subjects

Bernhardt, P.

Publications and source records attributed to Bernhardt, P..

4 recordsLinked to original sources

bioRxiv2026

A Deformulating Multi-Attribute SEC Method for Simultaneous Quantification of Total RNA, Conjugated Antibody, and Free Antibody in Targeted Lipid Nanoparticles

Targeted lipid nanoparticles (tLNPs) hold promise for improving cell- and tissue-selective delivery of therapeutic payloads but introduce analytical challenges associated with characterizing both encapsulated cargo and surface-associated targeting ligands within the same formulation. Conventional nucleic acid and protein assays can be affected by nanoparticle scattering, matrix interference, or a limited ability to distinguish conjugated antibody from free antibody. Here, we report an online deformulating size-exclusion high-performance liquid chromatography (SE-HPLC) method that enables simultaneous quantification of total RNA, conjugated antibody, and free antibody from 5 L of tLNP sample. Following injection, exposure to a mobile phase containing sodium dodecyl sulfate and isopropanol disrupts the nanoparticles, enabling chromatographic separation of RNA, conjugated antibody, and free (unconjugated) antibody while minimizing sample handling prior to analysis. RNA was quantified by UV260 detection, whereas antibody was quantified by UV280 or intrinsic fluorescence detection to maximize sensitivity. The method demonstrated linear response over the evaluated concentration ranges, spike recoveries of 88-122%, and precision below 5% relative standard deviation. Application to purified tLNP formulations demonstrated simultaneous assessment of total RNA and conjugated antibody content, while confirming the absence of detectable free antibody following purification. Together, these results establish online deformulating SE-HPLC as a practical multi-attribute analytical method for characterization of tLNPs, enabling concurrent assessment of total RNA concentration, conjugated antibody concentration, and free antibody concentration using standard HPLC instrumentation.

biophysics↗

bioRxiv2024

Comparison of the tolerability of terbium-161 and lutetium-177 in combination with somatostatin analogues in the preclinical setting

Purpose[177Lu]Lu-DOTATATE is an established somatostatin receptor (SSTR) agonist for the treatment of metastasized neuroendocrine neoplasms, while the SSTR antagonist [177Lu]Lu-DOTA-LM3 has only scarcely been employed in clinics. Impressive preclinical data obtained with [161Tb]Tb-DOTA-LM3 in tumor-bearing mice indicated the potential of terbium-161 as an alternative to lutetium-177. The aim of the present study was to compare the tolerability of 161Tb- and 177Lu-based DOTA-LM3 and DOTATATE in immunocompetent mice. MethodsDosimetry calculations were performed based on biodistribution data of the radiopeptides in immunocompetent mice. Treatment-related effects on blood cell counts were assessed on Days 10, 28 and 56 after application of [161Tb]Tb-DOTA-LM3 or [161Tb]Tb-DOTATATE at 20 MBq per mouse. These radiopeptides were also applied at 100 MBq per mouse and the effects compared to those observed after application of the 177Lu-labeled counterparts. Bone marrow smears, blood plasma parameters and organ histology were assessed at the end of the study. ResultsThe absorbed organ dose was commonly higher for the SSTR antagonist than for the SSTR agonist and for terbium-161 over lutetium-177. Application of a therapeutic activity level of 20 MBq [161Tb]Tb-DOTA-LM3 or [161Tb]Tb-DOTATATE was well tolerated without major hematological changes. The injection of 100 MBq of the 161Tb- and 177Lu-based somatostatin analogues affected the blood cell counts, however. The lymphocytes were 40-50% lower in treated mice compared to the untreated controls on Day 10 irrespective of the radionuclide employed. At the same timepoint, thrombocyte and erythrocyte counts were 30-50% and 6-12% lower, respectively, after administration of the SSTR antagonist (p<0.05) while changes were less pronounced in mice injected with the SSTR agonist. All blood cell counts were in the normal range on Day 56. Histological analyses revealed minimal abnormalities in the kidneys, liver and spleen of treated mice. No correlation was observed between the organ dose and frequency of the occurrence of abnormalities. ConclusionHematologic changes were more pronounced in mice treated with the SSTR antagonist than in those treated with the SSTR agonist. Despite the increased absorbed dose delivered by terbium-161 over lutetium-177, [161Tb]Tb-DOTA-LM3 and [161Tb]Tb-DOTATATE should be safe at activity levels that are recommended for their respective 177Lu-based analogues.

cancer biology↗

bioRxiv2021

Temporal and Spatial Niche Partitioning of Bumblebee Species (Apidae: Bombus) on a Himalayan Mountain

BackgroundBumblebees are essential pollinators in many ecosystems. To maintain such ecosystem functions, bumblebee diversity remains an important concern. We measured abundance and diversity of bumblebee species along an elevational gradient over three flowering seasons. We hypothesized that co-occurring bumblebees partition niches over time and space. MethodsWe sampled bumblebees at six different meadows along Yulong Snow Mountain (Yunnan, SW China), a region known for high bumblebee diversity, over summer months (2017 - 2019). We analyzed the standardized abundances of the workers from different bumblebee species over 11 weeklong periods. We also analyzed the standardized abundances of the workers of each species at each of the six different meadows. ResultsClear patterns of temporal niche partitioning were most apparent for the two, dominant species, B. friseanus and B. lepidus. Spatial niche partitioning was evident for rarer species which tended to be most abundant at lower elevations. ConclusionsTemporal and spatial niche partitioning are among two of the ways that bumblebee diversity is maintained on Yulong Snow Mountain. This has future implications if changing climate conditions disrupt partitioning leading to increased interspecific competition.

ecology↗

bioRxiv2021

Cypripedium wardii (Orchidaceae) employs pseudopollen with both reward and deception to attract both flis and bees as pollinators

O_LIFlowering plants always attract animals providing rewards or deceptive signals to gain reproductive success. However, there is no well-documented reporting about a pollination mechanism with both rewards and deceptive signals by a same object. We found Cypripedium wardii flowers seem to attract visitors by the white pseudopollenlike trichomes on labella in our preliminary field observation. C_LIO_LITo explore the pollination mechanism of Cypripedium wardii, especially, the ecological function of the pseudopollen-like trichomes, we conducted field observations, analyses of the traits of visitors and flowers, and breeding system experiments. C_LIO_LIThe white trichomes composed by multicellular moniliform hairs on the floral labella played a crucial role to attract pollinators, causing a high natural fruit set ratio in C. wardii. We established the direct connection of the white trichomes and real pollen. C_LIO_LIWe propose that flowers of C. wardii provide pseudopollen to attract suitable bees and hoverflies as pollinators. And our evidence indicate that the pseudopollen owns both deceptive and rewarding ecological functions. Our study provide a clear pollination mechanism with both rewards and deceptive signals by a same object in angiosperm for the first time. However, an inbreeding depression seem to be caused by this strategy. And we speculated that the pollen mimicry strategy with both rewarding and deceptive functions in C. wardii may be an adaptation to the habitat fragmentation of this species to gain a reproductive assurance. C_LI

plant biology↗