11-cis-retinal and Eye-Abnormalities

Pesticide stress is one of the important factors for global bee declines. Apart from physiological and developmental anomalies, pesticides also impose cognitive damages on bees. The present study investigates the visual acuity of wild populations of honey bees, in an agricultural intensification landscape, and corroborates the findings with controlled laboratory experiments. Even though overall morphometric examinations revealed no significant differences between the populations, correct color choices by bees in pesticide exposed populations were significantly reduced. The study reports, for the first time, the significant reduction in ommatidia facet diameter in these populations, as viewed under scanning electron microscope, along with the molecular underpinnings to these findings. Western blot studies revealed a significant reduction in expression of two visual proteins - blue-sensitive opsin and rhodopsin - in the pesticide exposed populations in both field and laboratory conditions. The novel findings from this study form the basis for further investigations into the effects of field realistic doses of multiple pesticide exposures on wild populations of honey bees.

Topics: Agriculture; Animals; Bees; Eye; Eye Abnormalities; Microscopy, Electron, Scanning; Opsins; Pesticides; Rhodopsin; Visual Acuity

Topics: Adult; Child; Eye Abnormalities; Female; Fluorescence; Humans; Lipofuscin; Macula Lutea; Male; Optic Disk; Photography; Photoreceptor Cells, Vertebrate; Pigment Epithelium of Eye; Pyridinium Compounds; Retinal Detachment; Retinoids; Rhodopsin; Tomography, Optical Coherence

The period (per) and timeless (tim) genes are required for circadian behavioral rhythms in Drosophila. The current model for how these rhythms entrain to light is based upon the light induced decrease in timeless protein (TIM) levels. We show here that the TIM response to light correlates with the effect of light on the behavioral rhythm. To identify components of the entrainment pathway, we also assayed the TIM response in flies with mutant visual systems. Flies that lacked eyes displayed a normal response in lateral neurons. The TIM response to a light pulse was attenuated in flies that were mutant for the transient receptor potential (trp) and trp-like (trpl) genes, which are required for calcium conductance in the visual transduction cascade. The reduced TIM response was accompanied by a reduced phase shift in the behavioral rhythm, but neither response was completely eliminated, and the trpl;trp flies entrain to light-dark cycles, suggesting that these genes perturb some aspect of circadian entrainment when mutated but are not essential for it. The TIM response was also unaffected in ninaE flies that lack the rhodopsin protein (rh1). These results support the hypothesis that circadian entrainment does not rely on the visual system and likely involves a dedicated pathway for photoreception.

Topics: Animals; Behavior, Animal; Calcium Channels; Circadian Rhythm; Dose-Response Relationship, Radiation; Drosophila; Drosophila Proteins; Eye Abnormalities; Eye Proteins; Insect Proteins; Light; Mutation; Neurons; Photoreceptor Cells, Invertebrate; Reference Values; Rhodopsin; TRPC Cation Channels