Biology subjects

Bol, S.

Publications and source records attributed to Bol, S..

3 recordsLinked to original sources

bioRxiv2022

Behavioral differences among domestic cats in the response to cat-attracting plants and their volatile compounds reveal a potential distinct mechanism of action for actinidine

It has been known for centuries that cats respond euphorically to Nepeta cataria (catnip). Recently, we have shown that Lonicera tatarica (Tatarian honeysuckle), Actinidia polygama (silver vine) and Valeriana officinalis (valerian) can also elicit this "catnip response". The aim of this study was to learn if the behavior seen in response to these plants is similar to the response to catnip. Furthermore, we studied if these responses are fixed or if there are differences between cats. While nepetalactone was identified decades ago as the molecule responsible for the "catnip response", we know that this volatile is found almost exclusively in catnip. Therefore, we also aimed to identify other compounds in these alternative plants that can elicit the blissful behavior in cats. Bioassays with 6 cats were performed in a stress-free environment, where 6 plants and 13 single compounds were each tested for at least 100 and 17 hours, respectively. All responses were video recorded and BORIS software was used to analyze the cats behavior. Both response duration and behavior differed significantly between the cats. While individual cats had preferences for particular plants, the behavior of individual cats was consistent among all plants. About half a dozen lactones similar in structure to nepetalactone were able to elicit the "catnip response", as were the structurally more distinct molecules actinidine and dihydroactinidiolide. Most cats did not respond to actinidine, whereas those who did, responded longer to this volatile than any of the other secondary plant metabolites, and different behavior was observed. Interestingly, dihydroactinidiolide was also found in excretions and secretions of the red fox, making this the first report of a compound produced by a mammal, that can elicit the "catnip response". A range of different cat-attracting compounds was detected by chemical analysis of plant materials but differences in cat behavior could not be directly related to differences in chemical composition of the plants. Together with among other results of habituation / dishabituation experiments, this indicates that additional cat-attracting compounds may be present in the plant materials that remain to be discovered. Collectively, these findings suggest that both the personality of the cat and genetic variation in the genes encoding olfactory receptors may play a role in how cats respond to cat-attracting plants. Furthermore, the data suggest a potential distinct mechanism of action for actinidine.

animal behavior and cognition↗

bioRxiv2021

A comparative analysis of memory B cell and antibody responses against Plasmodium falciparum merozoite surface protein 1 in children and adults from Uganda

Memory B cells (MBCs) and plasma antibodies against Plasmodium falciparum merozoite antigens are important components of the protective immune response against malaria. To gain understanding of how responses against P. falciparum develop in these two arms of the humoral immune system, we evaluated MBC and antibody responses against the most abundant merozoite antigen, merozoite surface protein 1 (MSP1), in individuals from a region in Uganda with high P. falciparum transmission. Our results showed that MSP1-specific B cells in adults with immunological protection against malaria were predominantly IgG+ classical MBCs, while children with incomplete protection mainly harbored IgM+ MSP1-specific classical MBCs. In contrast, anti-MSP1 plasma IgM reactivity was minimal in both children and adults. Instead, both groups showed high plasma IgG reactivity against MSP1 and whole merozoites, with broadening of the response against non-3D7 strains in adults. The antibodies encoded by MSP1-specific IgG+ MBCs carried high levels of amino acid substitutions and recognized relatively conserved epitopes on the highly variable MSP1 protein. Proteomics analysis of MSP119-specific IgG in plasma of an adult revealed a limited repertoire of anti-MSP1 antibodies, most of which were IgG1 or IgG3. Similar to MSP1- specific MBCs, anti-MSP1 IgGs had relatively high levels of amino acid substitutions and their sequences were predominantly found in classical MBCs, not atypical MBCs. Collectively, these results showed evolution of the MSP1-specific humoral immune response with cumulative P. falciparum exposure, with a shift from IgM+ to IgG+ B cell memory, diversification of B cells from germline, and stronger recognition of MSP1 variants by the plasma IgG repertoire.

immunology↗

bioRxiv2021

SARS-CoV-2 spike-specific memory B cells express markers of durable immunity after non-severe COVID-19 but not after severe disease

SARS-CoV-2 infection elicits a robust B cell response, resulting in the generation of long-lived plasma cells and memory B cells. Here, we aimed to determine the effect of COVID-19 severity on the memory B cell response and characterize changes in the memory B cell compartment between recovery and five months post-symptom onset. Using high-parameter spectral flow cytometry, we analyzed the phenotype of memory B cells with reactivity against the SARS-CoV-2 spike protein or the spike receptor binding domain (RBD) in recovered individuals who had been hospitalized with non-severe (n=8) or severe (n=5) COVID-19. One month after symptom onset, a substantial proportion of spike-specific IgG+ B cells showed an activated phenotype. In individuals who experienced non-severe disease, spike-specific IgG+ B cells showed increased expression of markers associated with durable B cell memory, including T-bet, FcRL5, and CD11c, which was not observed after severe disease. Five months post-symptom onset, the majority of spike-specific memory B cells had a resting phenotype and the percentage of spike-specific T-bet+ IgG+ memory B cells decreased to baseline levels. Collectively, our results suggest that the memory B cell response elicited during non-severe COVID-19 may be of higher quality than the response after severe disease.

immunology↗