Biology subjects

Barnea, A.

Publications and source records attributed to Barnea, A..

3 recordsLinked to original sources

bioRxiv2023

When Night Becomes Day: Artificial Light at Night Alters Insect Behavior under Semi-Natural Conditions

Light is the most important Zeitgeber for temporal synchronization in nature. Artificial light at night (ALAN) disrupts the natural light-dark rhythmicity and thus negatively affects animal behavior. However, to date, ALAN research has been mostly conducted under laboratory conditions in this context. Here, we used the field cricket, Gryllus bimaculatus, to investigate the effect of ALAN on insect behavior under semi-natural conditions, i.e., under shaded natural lighting conditions, natural temperature and soundscape. Male crickets were placed individually in outdoor enclosures and exposed to ALAN conditions ranging from <0.01 to 1,500 lx intensity. The crickets stridulation behavior was recorded for 14 consecutive days and nights and their daily activity patterns were analysed. ALAN impaired the crickets stridulation rhythm, evoking a change in the crickets naturally synchronized daily activity period. This was manifested by a light-intensity-dependent increase in the proportion of insects demonstrating an intrinsic circadian rhythm (free-run behavior). This also resulted in a change in the populations median activity cycle period. These ALAN-induced effects occurred despite the crickets exposure to almost natural conditions. Our findings provide further validity to our previous studies on ALAN conducted under lab conditions and establish the deleterious impacts of ALAN on animal behavioral patterns. HighlightsO_LIALAN presents a threat for insect populations and biodiversity C_LIO_LIThe impact of ALAN on insect behavior is mostly studied under laboratory conditions C_LIO_LIWe studied the effects of ALAN on cricket stridulation in semi-natural conditions C_LIO_LIALAN clearly affected the crickets behavior in a light-intensity dependent manner C_LIO_LIThe behavioral effects of ALAN were revealed despite the semi-natural environment C_LIO_LIALAN represents a threat for cricket populations fitness C_LI

animal behavior and cognition↗

bioRxiv2022

Transcriptional response of circadian clock genes to an 'artificial light at night' pulse in the cricket Gryllus bimaculatus

Light is the major signal entraining the circadian clock that regulates physiological and behavioral rhythms in most organisms, including insects. Artificial Light at Night (ALAN) disrupts the natural light-dark cycle and negatively impacts animals at various levels. We simulated ALAN using dim light stimuli and tested their impact on gene expression in the cricket Gryllus bimaculatus, a model of insect physiology and chronobiology. At night, adult LD crickets were exposed for 30 minutes to a light pulse of 2-40 lx. The relative expression of five circadian clock associated genes was compared using qPCR. A dim ALAN pulse elicited tissue-dependent differential expression in some of these genes. The strongest effect was observed in the brain and in the optic lobe, the crickets circadian pacemaker. Expression of opsin-Long Wave (opLW) was upregulated, as well as cryptochrome1-2 (cry), and period (per). Our findings demonstrate that even a dim ALAN exposure may affect insects at the molecular level, underscoring the detrimental impact of ALAN on the circadian clock system.

animal behavior and cognition↗

bioRxiv2021

Isolation and characterization of a highly specific monoclonal antibody targeting the botulinum neurotoxin type E exposed SNAP-25 neoepitope

Botulinum neurotoxin type E (BoNT/E), the fastest acting toxin of all BoNTs, cleaves the 25 kDa synaptosomal associated protein (SNAP-25) in motor neurons, leading to flaccid paralysis. Specific detection and quantification of BoNT/E-cleaved SNAP-25 neoepitope is essential for diagnosis of BoNT/E intoxication as well as for characterization of anti-BoNT/E antibody preparations. In order to isolate highly specific monoclonal antibodies suitable for in vitro immuno-detection of the exposed neoepitope, mice and rabbits were immunized with an eight amino acid peptide composed of the C-terminus of the cleaved SNAP-25. Immunized rabbits developed a specific and robust polyclonal antibody response, whereas immunized mice mostly demonstrated a weak antibody response that could not discriminate between the two forms of SNAP-25. An immune scFv phage-display library was constructed from the immunized rabbits and a panel of antibodies was isolated. Sequence alignment of the isolated clones revealed high similarity between both heavy and light chains, with exceptionally short HCDR3 sequences. A chimeric scFv-Fc antibody was further expressed and characterized, exhibiting a selective, ultra-high affinity (pM) towards the SNAP-25 neoepitope. Moreover, this antibody enabled sensitive detection of the cleaved SNAP-25 in BoNT/E treated SiMa cells with no cross reactivity with the intact SNAP-25. This novel antibody can be further used to develop an in vitro cell-based assay to diagnose BoNT/E intoxication and to characterize antitoxin preparations, thus eliminating the use of animals in the standard mouse bioassay.

biochemistry↗