Biology subjects

Stec, D.

Publications and source records attributed to Stec, D..

6 recordsLinked to original sources

bioRxiv2025

Do shifts in honeybee crop microbiota enable ethanol accumulation? A comparative analysis of caged and foraging bees

Honeybees encounter low environmental doses of ethanol, primarily through fermenting nectar, which can have both beneficial and detrimental effects on their functioning. Yet, ethanol traces can also be detected in the crop of caged bees with no access to environmental food sources. This raises the possibility that endogenous ethanol accumulation could occur under restricted conditions, with microbial contributions as a potential mechanism. The crop microbiota, although less diverse than that in other gut segments, plays important roles in food fermentation and pathogen defense. We hypothesized that captivity-induced shifts in crop microbiota may facilitate fermentation, resulting in measurable ethanol. To test this, we compared the crop contents of naturally foraging hive bees and caged bees reared without access to the natural environment. Ethanol levels were low in both groups and did not differ significantly, but non-zero measurements were more frequently observed in caged bees. Microbial community structure differed strongly in - and {beta}-diversity. Caged bees showed reduced abundance of nectar-associated genera (e.g., Apilactobacillus) and an increase in genera that include known ethanol-producing strains, such as Gilliamella and Bifidobacterium. While we did not directly assess metabolic activity, our results suggest that captivity alters microbial communities in ways that may influence ethanol levels. This raises broader questions about how microbe-host interactions modulate host phenotypes under different environmental conditions.

ecology↗

bioRxiv2025

Honeybees show an increased preference for dietary alcohol when parasitized

Parasitic infections often alter host behavior, including foraging and the consumption of bioactive substances. In honeybees (Apis mellifera), infection with the common gut parasite Nosema ceranae causes metabolic disruption and increased mortality. Ethanol is a naturally occurring bioactive compound found in nectar, and honeybees exhibit high tolerance and resilience to chronic exposure. However, whether bees actively use ethanol during infection remains unclear. Here, we investigated whether N. ceranae-infected honeybees alter their ethanol consumption. In a feeding experiment, infected and uninfected bees were given a choice between plain sucrose solution and ethanol-spiked food (0.5% or 1% ethanol). We measured food consumption, survival, and spore load. Although overall food intake did not differ between groups, infected bees consumed a significantly higher proportion of ethanol-spiked food. Survival analysis showed that a diet containing 1% ethanol caused higher mortality than a diet containing 0.5% ethanol; however, among bees on a 1% ethanol diet, this negative effect was less pronounced in infected individuals than in controls. Spore load did not differ between treatments. These results suggest that N. ceranae infection induces a shift in feeding behavior towards increased ethanol intake, which may benefit infected bees by reducing mortality. This may reflect a self-medication response, although alternative explanations - such as parasite-induced manipulation or ethanol-induced changes in host physiology and immunity - remain possible. Further research into ethanols effects on Nosema spores is needed. Nonetheless, our findings provide insights into honeybee interactions with bioactive compounds and suggest that ethanol may be a behaviorally relevant dietary substance.

pathology↗

bioRxiv2024

Honey bees are resilient to the long-term presence of alcohol in their diet

Previous studies on various organisms have suggested that low doses of ethanol can have stimulatory effects, while higher doses may lead to toxicity, a response known as hormesis. Low ethanol concentrations occur naturally in the environment, particularly in fermenting fruits and flower nectar, where pollinators such as honey bees may encounter it. This study aimed to investigate the potential hormetic effects of low-level ethanol consumption on honey bees. Bees were divided into three groups: one provided with only sucrose solution, one both with sucrose and 0.5% ethanol in sucrose, and one with only 1% ethanol in sucrose. The bees were exposed to these diets for 14 days, and their performance was assessed through survivorship, flight endurance, body mass, lipid content, and trehalose and ethanol levels in the haemolymph. The results showed no significant differences in most parameters between the groups. However, bees constantly exposed to 1% ethanol had slightly higher trehalose levels compared to the control group, suggesting a possible adaptive response to ethanol exposure. Ethanol levels in the haemolymph differed significantly between groups, with bees exposed to ethanol showing its detectable levels in their system. While no clear hormetic effects were observed in terms of improved performance, the elevated trehalose levels in bees constantly exposed to 1% ethanol may indicate adaptations protecting from ethanol-induced damage. The study provides insights into how honey bees tolerate low-level ethanol exposure and highlights the need for further research on the ecological implications of ethanol consumption in pollinators.

physiology↗

bioRxiv2024

Occasional and constant exposure to dietary ethanol shortens the lifespan of worker honey bees

Honey bees (Apis mellifera) are one of the most crucial pollinators, providing vital ecosystem services. Their development and functioning depend on essential nutrients and substances found in the environment. While collecting nectar as a vital carbohydrate source, bees routinely encounter low doses of ethanol from yeast fermentation. Yet, the effects of repeated ethanol exposure on bees survival and physiology remain poorly understood. Here, we investigate the impacts of constant and occasional consumption of food spiked with 1% ethanol on honey bee mortality and alcohol dehydrogenase (ADH) activity. This ethanol concentration might be tentatively judged close to that in natural conditions. We conducted an experiment in which bees were exposed to three types of long-term diets: constant sugar solution (control group that simulated conditions of no access to ethanol), sugar solution spiked with ethanol every third day (that simulated occasional, infrequent exposure to ethanol) and daily ethanol consumption (simulating constant, routine exposure to ethanol). The results revealed that both constant and occasional ethanol consumption increased the mortality of bees, but only after several days. These mortality rates rose with the frequency of ethanol intake. The ADH activity remained similar in bees from all groups. Our findings indicate that exposure of bees to ethanol carries harmful effects that accumulate over time. Further research is needed to pinpoint the exact ethanol doses ingested with food and exposure frequency in bees in natural conditions.

physiology↗

bioRxiv2024

Pinpointing the microbiota of tardigrades: what is really there?

Microbiota have been proposed as an important aspect of tardigrade biology, but little is known about their diversity and distribution. Here, we attempted to characterize the microbiota of 44 cultured species of tardigrades using 16S rRNA amplicon sequencing, using different specimen pooling strategies, various DNA extraction kits, and multiple types of controls. We also estimated the number of microbes in samples using synthetic DNA spike-ins. Additionally, we reanalyzed data from previous studies. Our results suggest that the microbial community profiles of cultured tardigrades are dominated by bacterial OTUs and genotypes originating from food, medium, or laboratory reagents. We found microbial strains consistently enriched in certain tardigrades (relative to the culture media and controls), which indicates likely symbiotic associations, but the reads representing putative true tardigrade-associated microbes rarely exceeded 20% of the datasets. Some of the identified tardigrade-associated microbes matched symbionts identified by other studies. However, we also identified serious contamination issues with previous studies of tardigrade microbiome, making some of their conclusions questionable. We conclude that tardigrades are not universally dependent on specialized microbes and highlight the necessary safeguards in future studies of the microbiota of microscopic organisms.

microbiology↗

bioRxiv2023

A Living Organoid Biobank of Crohn's Disease Patients Reveals Molecular Subtypes for Personalized Therapeutics

ABSTRACT (Structured)Crohns disease (CD) is a complex, clinically heterogeneous disease of multifactorial origin; there is no perfect pre-clinical model, little insight into the basis for such heterogeneity, and still no cure. To address these unmet needs, we sought to explore the translational potential of adult stem cell-derived organoids that not only retain their tissue identity, but also their genetic and epigenetic disease-driving traits. We prospectively created a biobank of CD patient-derived organoid cultures (PDOs) using biopsied tissues from colons of 34 consecutive subjects representing all clinical subtypes (Montreal Classification B1-B3 and perianal disease). PDOs were generated also from healthy subjects. Comparative gene expression analyses enabled benchmarking of PDOs as tools for modeling the colonic epithelium in active disease and revealed that despite the clinical heterogeneity there are two major molecular subtypes: immune-deficient infectious-CD [IDICD] and stress and senescence-induced fibrostenotic-CD [S2FCD]. The transcriptome, genome and phenome show a surprising degree of internal consistency within each molecular subtype. The spectrum of morphometric, phenotypic, and functional changes within the "living biobank" reveals distinct differences between the molecular subtypes. These insights enabled drug screens that reversed subtype-specific phenotypes, e.g., impaired microbial clearance in IDICD was reversed using agonists for nuclear receptors, and senescence in S2FCD was rectified using senotherapeutics, but not vice versa. Phenotyped-genotyped CD-PDOs may fill the gap between basic biology and patient trials by enabling pre-clinical Phase 0 human trials for personalized therapeutics. GRAPHIC ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/532245v1_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@1edcea0org.highwire.dtl.DTLVardef@198a3c8org.highwire.dtl.DTLVardef@28d394org.highwire.dtl.DTLVardef@5a9dbb_HPS_FORMAT_FIGEXP M_FIG C_FIG In BriefThis work creates a prospectively biobanked phenotyped-genotyped Crohns disease patient-derived organoids (CD-PDOs) as platforms for molecular subtyping of disease and for ushering personalized therapeutics. HIGHLIGHTSO_LIProspectively biobanked CD-organoids recapitulate the disease epithelium in patients C_LIO_LIThe phenome-transcriptome-genome of CD-organoids converge on two molecular subtypes C_LIO_LIOne subtype shows impaired microbial clearance, another increased cellular senescence C_LIO_LIPhenotyped-genotyped PDOs are then used for integrative and personalized therapeutics C_LI

immunology↗