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- The Expression of Three Opsin Genes from the Compound Eye of Helicoverpa armigera (Lepidoptera: Noctuidae) Is Regulated by a Circadian Clock, Light Conditions and Nutritional Status. [JOURNAL ARTICLE]
- PLoS One 2014; 9(10):e111683.
Visual genes may become inactive in species that inhabit poor light environments, and the function and regulation of opsin components in nocturnal moths are interesting topics. In this study, we cloned the ultraviolet (UV), blue (BL) and long-wavelength-sensitive (LW) opsin genes from the compound eye of the cotton bollworm and then measured their mRNA levels using quantitative real-time PCR. The mRNA levels fluctuated over a daily cycle, which might be an adaptation of a nocturnal lifestyle, and were dependent on a circadian clock. Cycling of opsin mRNA levels was disturbed by constant light or constant darkness, and the UV opsin gene was up-regulated after light exposure. Furthermore, the opsin genes tended to be down-regulated upon starvation. Thus, this study illustrates that opsin gene expression is determined by multiple endogenous and exogenous factors and is adapted to the need for nocturnal vision, suggesting that color vision may play an important role in the sensory ecology of nocturnal moths.
- The colorful language of Australian flowers. [Journal Article]
- Commun Integr Biol 2014.:e28940.
The enormous increase in phylogenetic information in recent years has allowed many old questions to be reexamined from a macroevolutionary perspective. We have recently considered evolutionary convergence in floral colors within pollination syndromes, using bird-pollinated species in Australia. We combined quantitative measurements of floral reflectance spectra, models of avian color vision, and a phylogenetic tree of 234 Australian species to show that bird-pollinated flowers as a group do not have colors that are significantly different from the colors of insect-pollinated flowers. However, about half the bird-pollinated flowers have convergently evolved a narrow range of colors with dominant long-wavelength reflection far more often than would be expected by chance. These convergent colors would be seen as distinctly different from other floral colors in our sample when viewed by honeyeaters (family Meliphagidae), birds with a phylogenetically ancestral type of color vision and the dominant avian pollinators in Australia. Our analysis shows how qualitative ideas in natural history, like the concept of pollination syndromes, can be given more precise definition and rigorous statistical testing that takes into account phylogenetic information.
- Quantifying the watercolor effect: from stimulus properties to neural models. [Journal Article]
- Front Hum Neurosci 2014.:805.
- Nutritional optic neuropathy. [Journal Article]
- Klin Oczna 2014; 116(2):104-10.
Nutritional optic neuropathy (aka deficiency optic neuropathy) is a dysfunction of the optic nerve resulting from improper dietary content of certain nutrients essential for normal functioning of the nerve fibers. Most commonly, it results from folic acid and vitamin B complex deficiency associated with malnutrition or poor dietary habits, incorrectly applied vegetarian diet, or chronic alcohol abuse. Obese patients after bariatric surgery constitute another risk group of optic neuropathy. Nutritional optic neuropathy is characterized by painless, gradually progressing, bilateral and symmetrical decrease in visual acuity, which can be accompanied by the color vision dysfunction. Progression of the neuropathy is associated with optic nerve atrophy, manifesting as complete disc pallor. Treatment of nutritional neuropathy includes dietary supplementation, aimed at compensating for the deficient nutrients. The treatment is mostly based on folic acid, vitamin B complex, and protein replacement, as well as eliminating risk factors of neuropathy. Early treatment commencement, prior to irreversible optic nerve atrophy, is a prerequisite of effective treatment. We would like to highlight this problem by presenting the case of a young woman in whom chronic use "water-based" diet resulted in anemia and bilateral nutritional optic neuropathy.
- Colour vision in ADHD: Part 1 - Testing the retinal dopaminergic hypothesis. [JOURNAL ARTICLE]
- Behav Brain Funct 2014 Oct 24; 10(1):38.
Objectives To test the retinal dopaminergic hypothesis, which posits deficient blue color perception in ADHD, resulting from hypofunctioning CNS and retinal dopamine, to which blue cones are exquisitely sensitive. Also, purported sex differences in red color perception were explored.30 young adults diagnosed with ADHD and 30 healthy young adults, matched on age and gender, performed a psychophysical task to measure blue and red color saturation and contrast discrimination ability. Visual function measures, such as the Visual Activities Questionnaire (VAQ) and Farnsworth-Munsell 100 hue test (FMT), were also administered.Females with ADHD were less accurate in discriminating blue and red color saturation relative to controls but did not differ in contrast sensitivity. Female control participants were better at discriminating red saturation than males, but no sex difference was present within the ADHD group.Poorer discrimination of red as well as blue color saturation in the female ADHD group may be partly attributable to a hypo-dopaminergic state in the retina, given that color perception (blue-yellow and red-green) is based on input from S-cones (short wavelength cone system) early in the visual pathway. The origin of female superiority in red perception may be rooted in sex-specific functional specialization in hunter-gather societies. The absence of this sexual dimorphism for red colour perception in ADHD females warrants further investigation.
- Color vision in ADHD: Part 2 - Does Attention influence Color Perception? [JOURNAL ARTICLE]
- Behav Brain Funct 2014 Oct 24; 10(1):39.
To investigate the impact of exogenous covert attention on chromatic (blue and red) and achromatic visual perception in adults with and without Attention Deficit Hyperactivity Disorder (ADHD). Exogenous covert attention, which is a transient, automatic, stimulus-driven form of attention, is a key mechanism for selecting relevant information in visual arrays.30 adults diagnosed with ADHD and 30 healthy adults, matched on age and gender, performed a psychophysical task designed to measure the effects of exogenous covert attention on perceived color saturation (blue, red) and contrast sensitivity.The effects of exogenous covert attention on perceived blue and red saturation levels and contrast sensitivity were similar in both groups, with no differences between males and females. Specifically, exogenous covert attention enhanced the perception of blue saturation and contrast sensitivity, but it had no effect on the perception of red saturation.The findings suggest that exogenous covert attention is intact in adults with ADHD and does not account for the observed impairments in the perception of chromatic (blue and red) saturation.
- Pathogenic Mitochondrial DNA Mutations and Associated Clinical Features in Korean Patients with Leber's Hereditary Optic Neuropathy. [JOURNAL ARTICLE]
- Invest Ophthalmol Vis Sci 2014 Oct 23.
Purpose:To identify the spectrum of pathogenic mitochondrial DNA (mtDNA) mutations and clinical features in Korean patients with genetically confirmed Leber's hereditary optic neuropathy (LHON). Methods:The medical records of 34 unrelated genetically confirmed LHON patients were reviewed. Total genomic DNA was isolated from the peripheral blood leukocytes of the patients with suspected LHON, and primary or secondary mtDNA mutations were identified by direct sequencing. We analyzed the visual acuity (VA), color vision, RNFL thickness, and visual field at the final visit from 20 patients who were followed up for more than 6 months after the onset of LHON. Results:Among 34 patients, 21 (61.8%) had the homoplasmic primary mutation, 11 (32.4%) had the homoplasmic secondary mutation and 2 (5.9%) had the heteroplasmic primary mutation along with the homoplasmic secondary mutation. Analysis of mtDNA sequences revealed six different types of LHON-associated mutations: two primary LHON-associated primary mutations, m.11778G>A (20 patients, 58.8%) and m.14484T>C (3 patients, 8.8%), and four secondary LHON-associated mutations, which were m.3394T>C (3 patients, 8.8%), m.3497C>T (4 patients, 11.8%), m.11696G>A (4 patients, 11.8%), and m.14502T>C (2 patients, 5.9%). Secondary mutation-carrying patients demonstrated a decreased in RNFL thickness, similar to those in primary mutation-carrying LHON patients. These patients had a higher female ratio (p=0.019), better VA (p=0.043) and color vision (p=0.005), as well as better visual field. Conclusions:In addition to common primary LHON-associated mutations, our study identified secondary mtDNA mutations which should be considered when evaluating patients with optic atrophy.
- POEMS syndrome as an uncommon cause of papilledema. [Journal Article]
- Nepal J Ophthalmol 2014 Jan; 6(11):105-8.
Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome is an uncommon condition related to a paraneoplastic syndrome secondary to an underlying plasma cell disorder. Among the myriad of manifestations of the disease, ocular signs and symptoms are relatively prevalent, affecting about half of all patients with the disease.To report the ocular manifestations of POEMS syndrome.A 47-year-old lady diagnosed to have POEMS syndrome presented with painless progressive visual diminution. Her color vision was impaired. There was bilateral papilloedema.POEMS syndrome should be considered among the differential diagnoses of all patients with a bilateral papilledema in which no other cause can be readily elucidated.
- Evans blue as a simple method to discriminate mosquitoes' feeding choice on small laboratory animals. [Journal Article]
- PLoS One 2014; 9(10):e110551.
Temperature, humidity, vision, and particularly odor, are external cues that play essential roles to mosquito blood feeding and oviposition. Entomological and behavioral studies employ well-established methods to evaluate mosquito attraction or repellency and to identify the source of the blood meal. Despite the efficacy of such methods, the costs involved in the production or acquisition of all parts, components and the chemical reagents involved are unaffordable for most researchers from poor countries. Thus, a simple and relatively low-cost method capable of evaluating mosquito preferences and the blood volume ingested is desirable.By using Evans blue (EB) vital dye and few standard laboratory supplies, we developed and validated a system capable of evaluating mosquito's choice between two different host sources of blood. EB-injected and PBS-injected mice submitted to a number of situations were placed side by side on the top of a rounded recipient covered with tulle fabric and containing Aedes aegypti mosquitoes. Homogenates from engorged mosquitoes clearly revealed the blood source (EB- or PBS-injected host), either visually or spectrometrically. This method was able to estimate the number of engorded mosquitoes, the volume of blood ingested, the efficacy of a commercial repellent and the attractant effects of black color and human sweat.Despite the obvious limitations due to its simplicity and to the dependence of a live source of blood, the present method can be used to assess a number of host variables (diet, aging, immunity, etc) and optimized for several aspects of mosquito blood feeding and vector-host interactions. Thus, it is proposed as an alternative to field studies, and it could be used for initial screenings of chemical compound candidates for repellents or attractants, since it replicates natural conditions of exposure to mosquitoes in a laboratory environment.
- Protan response times to red lights in a mildly hypoxic environment. [Journal Article]
- Aviat Space Environ Med 2014 Nov; 85(11):1078-85.
Hovis JK, Milburn NJ, Nesthus TE. Protan response times to red lights in a mildly hypoxic environment. Aviat Space Environ Med 2014; 85:1078-85.This study was conducted to determine whether protans have slower reaction times to red lights than individuals with normal color vision and to identify whether protan reaction times increase differentially in a mildly hypoxic environment.Simple reaction times (SRT) to a red light-emitting diode (LED) display were measured using the Psychomotor Vigilance Task (PVT) at ground (1293 ft/394 m), simulated 12,400-ft (3780-m) altitude, and 20 min after returning to ground. Subjects were 13 individuals with normal color vision (NCV), 12 with a deutan color vision defect, and 4 with a protan color vision defect.The mean reaction times increased by 8% with altitude and decreased after returning to ground for all groups. However, the reaction times of the protans were often faster than the NCV mean and never below the NCV 10(th) percentile. The only significant difference between color vision groups was the slowest mean reaction time of the NCV group was slower than both the pooled dichromats and pooled anomalous trichromats across all conditions by 23%. The number of lapses did not vary with altitude, but the dichromatic subjects had significantly fewer lapses than the trichromatic subjects across all conditions.Although protans may be slower to respond to some red warning lights, this decrement in performance could not be demonstrated under the conditions of our experiment. Furthermore, the protan group's simple reaction times were not differentially affected by mild hypoxia. These results suggest that the red LEDs were sufficiently bright for these protan observers.