Biology subjects

Lo, L. K.

Publications and source records attributed to Lo, L. K..

4 recordsLinked to original sources

bioRxiv2025

Covert infections with a honeybee virus induce fitness costs in ant colonies

Acute Bee Paralysis Virus (ABPV) is a key driver of honey bee colony losses that has been increasingly reported in non-bee hosts in the past decades. Ants have long been hypothesised to act as viral reservoirs, but most evidence comes from field surveys, and experimental tests are still scarce. Here, we combined survival and transmission assays, viral load measurements, viral replication assays, and host immune gene expression analyses to test whether the clonal raider ant Ooceraea biroi can harbour and transmit ABPV. ABPV-injected ants showed delayed development and elevated mortality. Although we found no evidence of viral replication, the virus was able to spread among colony members and viral particles persisted in colonies for several days. These results show that ants can acquire ABPV, incur fitness costs, and pass the virus within their colonies, suggesting that they may act as incidental viral reservoirs. By maintaining and disseminating honey bee viruses, even without supporting replication, ants could contribute to their environmental persistence and spillover across species.

pathology↗

bioRxiv2025

Experimental Removal of Niche Construction Alters the Pace and Mechanisms of Resistance Evolution

Niche construction, a central eco-evolutionary process in which organisms modify their environment, is hypothesised to enhance evolutionary adaptability through feedback between genetic inheritance and the lasting effects of environmental change--known as ecological inheritance. However, while theoretically intriguing, direct empirical support for the effect of niche construction on adaptation is lacking. Red flour beetles modify their environment by releasing quinone-rich stink gland secretions, a form of external immunity. Here, we test in an evolution experiment how experimental removal of niche construction--using RNAi of a key gene needed to produce stink gland secretions--affects the beetles adaptation to the bacterial entomopathogen Bacillus thuringiensis. In each generation, beetles inhabited conditioned flour either with regular or drastically reduced stink gland secretion content. Compared to the non-exposed control, all bacteria-exposed regimes rapidly evolved bacterial resistance within only six generations. However, beetles evolving with intact niche construction acquired resistance as soon as after three generations, indicating that adaptation was initially facilitated by niche construction. RNAseq of evolved beetles showed that gene expression differed strongly between the selection regimes, revealing that the mechanisms underlying resistance were dependent on niche construction. Thus, our findings provide urgently needed empirical evidence on the role of niche construction for resistance evolution and its potential genetic basis.

evolutionary biology↗

bioRxiv2021

Immune stimulation alters chemical profiles of Tribolium castaneum

Group-living individuals experience immerse risk of disease transmission and parasite infection. Especially in social, but also in some non-social insects, disease control with immunomodulation takes place not only via individual immune defenses, but also via infochemicals such as contact cues and (defensive) volatiles to mount a group level immunity. However, little is known about whether an activation of the immune system leads to changes in chemical phenotypes, which may mediate these responses. We here asked whether individual immune experience resulting from wounding or injection of heat-killed Bacillus thuringiensis leads to changes in the chemical profiles of female and male adult red flour beetles (Tribolium castaneum), which are non-social but gregarious. We analyzed insect extracts using GC-FID to study the chemical composition of (1) cuticular hydrocarbons (CHCs) as candidates for the transfer of immunity-related information between individuals via contact, and (2) stink gland secretions, with target analysis of benzoquinones as main active compounds regulating external immunity. Despite a pronounced sexual dimorphism in CHC profiles, wounding stimulation led to similar profile changes in males and females with increases in the proportion of methyl-branched alkanes compared to naive beetles. While changes in the overall secretion profiles were less pronounced, absolute amounts of benzoquinones were transiently elevated in wounded compared to naive females. We suggest that the changes in different infochemicals may mediate immune status signaling in the context of both internal and external immune responses in groups of this non-social insect, thus showing parallels to social immunity.

evolutionary biology↗

bioRxiv2019

Zinc can counteract selection for ciprofloxacin resistance

Antimicrobial resistance (AMR) has emerged as one of the most pressing global threats to public health. AMR evolution occurs in the clinic but also in the environment, where low concentrations of antibiotics and heavy metals can respectively select and co-select for resistance. While the selective potential for AMR of both antibiotics and metals is increasingly well-characterized, studies exploring the combined effect of both types of selective agents are rare. It has previously been demonstrated that fluoroquinolone antibiotics such as ciprofloxacin can chelate metal ions. To investigate how ciprofloxacin resistance is affected by the presence of metals, we quantified selection dynamics between a ciprofloxacin-susceptible and an isogenic ciprofloxacin-resistant Escherichia coli MG1655 strain across a gradient of ciprofloxacin concentrations in the presence and absence of Zinc cations (Zn2+). The minimal selective concentration (MSC) for ciprofloxacin resistance significantly increased up to 5-fold in the presence of Zn2+. No such effect on the MSC was found for gentamicin, an antibiotic not known to chelate zinc cations. Environmental pollution usually consists of complex mixtures of antimicrobial agents. Our findings highlight the importance of taking antagonistic as well as additive or synergistic interactions between different chemical compounds into account when considering their effect on bacterial resistance evolution.\n\nGraphical abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=150 SRC=\"FIGDIR/small/780981v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (23K):\norg.highwire.dtl.DTLVardef@9abc9eorg.highwire.dtl.DTLVardef@d54d48org.highwire.dtl.DTLVardef@1c4df88org.highwire.dtl.DTLVardef@2f67f6_HPS_FORMAT_FIGEXP M_FIG C_FIG One sentence summaryThe minimal selective concentration for a ciprofloxacin resistant E. coli strain increases up to 5-fold in the presence of Zinc cations.

microbiology↗