Ontogenetic changes in the visual acuity of Sepia officinalis measured using the optomotor response

2005 ◽  
Vol 83 (2) ◽  
pp. 274-279 ◽  
Author(s):  
G Groeger ◽  
P A Cotton ◽  
R Williamson
Keyword(s):  
Visual Acuity ◽  
Light Intensity ◽  
Whole Body ◽  
Sepia Officinalis ◽  
Ontogenetic Changes ◽  
Optomotor Response ◽  
Minimum Width ◽  
Size Classes ◽  
Black And White ◽  
Light Intensities

For many organisms vision is of fundamental importance to many aspects of their lives. Here we present the first study to examine the effects of ontogeny and light intensity on the vision of a cephalopod. We measured the visual acuity of four size classes of Sepia officinalis L., 1758 (common cuttlefish) under four light intensities. We used an optomotor testing system in which we recorded the unconditioned whole-body movements exhibited by individuals when placed inside a rotating cylinder lined with vertical black and white stripes. By varying the width of these stripes to determine the minimum width associated with a positive response, we were able to estimate the visual acuity angle or minimum separable angle (MSA). We found a significant effect of both body size and light intensity; larger animals had greater visual acuity, while individuals of all size classes discriminated more detail at higher light intensities. The minimum recorded MSA for S. officinalis was 34' of arc (0.57°) for the largest animals (80 mm) at the highest light intensity used (15 µW·cm–2). Decreasing light intensity from 15 to 4.5 µW·cm–2 affected animals of all sizes to approximately the same degree, reducing their visual acuity by approximately 55%.

Influence of Whole-Body Vertical Vibration on Vision Performance

1996 ◽  
Vol 15 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Barbara Harazin ◽  
Ladislav Louda ◽  
Krystyna Pawlas ◽  
Zdenek Jandak
Keyword(s):  
Visual Acuity ◽  
Whole Body Vibration ◽  
Mean Amplitude ◽  
Vertical Vibration ◽  
Whole Body ◽  
Sinusoidal Vibration ◽  
Body Vibration ◽  
Black And White ◽  
Clear Vision ◽  
Iso 2631

A new method of studying effects of whole-body vibration on visual acuity was developed. Nine seated subjects were exposed to vertical (z-axis) sinusoidal vibration with mean amplitude in the range of 0.9 to 11.2 ms−-2 r.m.s. Frequency responses of vibration levels resulting in equal 10% decrease of the visual acuity were determined for each subject over the frequency of 6.3 Hz to 63 Hz. The visual acuity was ascertained by the maximum distance of clear vision of black and white square field contours having a 1 mm side and arranged in a chessboard with total area of 1 cm x 1 cm. In comparison with the vertical weighting curve recommended by the Standard ISO 2631-1985, the slightly different mean contour of whole-body vibration required to produce the same decrement in visual acuity was found to be below 12.5 Hz and above 31.5 Hz.

Effect of light intensity on feeding of striped trumpeter Latris lineata larvae

1998 ◽  
Vol 49 (5) ◽  
pp. 363 ◽  
Author(s):  
Patricia M. Pankhurst ◽  
Pollyanna E. Hilder
Keyword(s):  
Light Intensity ◽  
Feeding Response ◽  
Ontogenetic Changes ◽  
Fish Feeding ◽  
First Feeding ◽  
Light Intensities ◽  
Latris Lineata ◽  
Striped Trumpeter ◽  
Dependent Behaviour ◽  
Effect Of Light

This study investigates the influence of light intensity on feeding of striped trumpeter larvae, correlating feeding responses with changes in morphology of the retina during growth. A pigmented single-cone retina had differentiated one day before first feeding, and rod precursor cells and double cones were visible in the retina on the 23rd, and 25th day after hatching, respectively. Feeding performance at four light intensities (0, 1, 30, 150 and 700 lux), revealed that striped trumpeter larvae are primarily dependent on vision, a light-dependent behaviour, to feed. The youngest larvae tested (15, 18 and 19 days of age) showed a poor feeding response at 1 lux (range 2–10%), but a 98–100% feeding response at 30, 50 and 700 lux. By 28 days of age, feeding behaviour had changed significantly, with 52% of fish now feeding at 1 lux, 100% of fish feeding at the intermediate light intensities of 30 and 150 lux, and only 62% of fish feeding at 700 lux. The apparent increased photopic sensitivity in 28-day-old fish may reflect increased areas for photon capture provided by double cones, or may reflect ontogenetic changes in cone spectral sensitivity.

Laboratory analyses of vision in tsetse flies (Dipt., Glossinidae)

1973 ◽  
Vol 62 (3) ◽  
pp. 343-357 ◽  
Author(s):  
D. A. Turner ◽  
J. F. Invest
Keyword(s):  
Visual Acuity ◽  
Sex Differences ◽  
Tsetse Flies ◽  
Background Illumination ◽  
Optomotor Response ◽  
Glossina Morsitans ◽  
Movement Perception ◽  
Black And White ◽  
Optimum Response ◽  
Slight Movement

Histological examination of the eyes ofGlossina morsitansWestw. andG. austeniNewst. showed that visual acuity, as calculated from ommatidial size and interommatidial angle, varies in different zones and planes of the eye, being greatest in the forward-facing region. A study of optomotor responses to revolving black-and-white striped patterns indicated that the eyes could perceive both rapid and very slight movement: responses showed a unimodal distribution with frequency of ommatidial stimulation ranging from one flash/25 s to around 80 flashes/s, with an optimum response at 5 flashes/s. Movement perception was also enhanced by summation of ommatidia simultaneously stimulated, provided the stimulated ommatidia were not contiguous. Strong optomotor response was shown to the movement of black stripes so narrow as to cause merely a 7% reduction in the amount of light entering an ommatidium: from this it was inferred that the eye's contrast sensitivity is well developed. Visual acuity determinations from optomotor responses showed no species or sex differences, and the values corresponded closely with those obtained from anatomical measurements. Of the properties of selected figures examined for attractiveness to orienting flies, linearity of form and brightness contrast with background illumination were deduced to be the most important aspects.

scholarly journals Integumentary Colour Allocation in the Stork Family (Ciconiidae) Reveals Short-Range Visual Cues for Species Recognition

Birds ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 138-146
Author(s):  
Eduardo J. Rodríguez-Rodríguez ◽  
Juan J. Negro
Keyword(s):  
Short Range ◽  
Visual Cues ◽  
Species Recognition ◽  
The Body ◽  
Whole Body ◽  
Divergent Evolution ◽  
Black And White ◽  
Extant Species ◽  
Chromatic Spectrum ◽  
Mixed Species Flocks

The family Ciconiidae comprises 19 extant species which are highly social when nesting and foraging. All species share similar morphotypes, with long necks, a bill, and legs, and are mostly coloured in the achromatic spectrum (white, black, black, and white, or shades of grey). Storks may have, however, brightly coloured integumentary areas in, for instance, the bill, legs, or the eyes. These chromatic patches are small in surface compared with the whole body. We have analyzed the conservatism degree of colouration in 10 body areas along an all-species stork phylogeny derived from BirdTRee using Geiger models. We obtained low conservatism in frontal areas (head and neck), contrasting with a high conservatism in the rest of the body. The frontal areas tend to concentrate the chromatic spectrum whereas the rear areas, much larger in surface, are basically achromatic. These results lead us to suggest that the divergent evolution of the colouration of frontal areas is related to species recognition through visual cue assessment in the short-range, when storks form mixed-species flocks in foraging or resting areas.

scholarly journals Effect of chlorophyll biosynthesis-related genes on the leaf color in Hosta (Hosta plantaginea Aschers) and tobacco (Nicotiana tabacum L.)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jingying Zhang ◽  
Changhai Sui ◽  
Huimin Liu ◽  
Jinjiao Chen ◽  
Zhilin Han ◽  
...  
Keyword(s):  
Light Intensity ◽  
Antioxidant Capacity ◽  
Aminolevulinic Acid ◽  
Chlorophyll Biosynthesis ◽  
Expression Level ◽  
Virus Induced Gene Silencing ◽  
Leaf Color ◽  
Color Changes ◽  
Light Intensities ◽  
Structure Changes

Abstract Background ‘Regal Splendour’ (Hosta variety) is famous for its multi-color leaves, which are useful resources for exploring chloroplast development and color changes. The expressions of chlorophyll biosynthesis-related genes (HrHEMA, HrPOR and HrCAO) in Hosta have been demonstrated to be associated with leaf color. Herein, we isolated, sequenced, and analyzed HrHEMA, HrPOR and HrCAO genes. Subcellular localization was also performed to determine the location of the corresponding enzymes. After plasmid construction, virus-induced gene silencing (VIGS) was carried out to reduce the expressions of those genes. In addition, HrHEMA-, HrPOR- and HrCAO-overexpressing tobacco plants were made to verify the genes function. Changes of transgenic tobacco were recorded under 2000 lx, 6000 lx and 10,000 lx light intensity. Additionally, the contents of enzyme 5-aminolevulinic acid (5-ALA), porphobilinogen (PBG), chlorophyll a and b (Chla and Chlb), carotenoid (Cxc), superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA), proline (Pro) and catalase (CAT) under different light intensities were evaluated. Results The silencing of HrHEMA, HrPOR and HrCAO genes can induce leaf yellowing and chloroplast structure changes in Hosta. Specifically, leaves of Hosta with HrCAO silencing were the most affected, while those with HrPOR silencing were the least affected. Moreover, all three genes in tobacco were highly expressed, whereas no expression was detected in wild-type (WT). However, the sensitivities of the three genes to different light intensities were different. The highest expression level of HrHEMA and HrPOR was detected under 10,000 lx of illumination, while HrCAO showed the highest expression level under 6000 lx. Lastly, the 5-ALA, Chla, Cxc, SOD, POD, MDA, Pro and CAT contents in different transgenic tobaccos changed significantly under different light intensities. Conclusion The overexpression of these three genes in tobacco enhanced photosynthesis by accumulating chlorophyll content, but the influential level varied under different light intensities. Furthermore, HrHEMA-, HrPOR- and HrCAO- overexpressing in tobacco can enhance the antioxidant capacity of plants to cope with stress under higher light intensity. However, under lower light intensity, the antioxidant capacity was declined in HrHEMA-, HrPOR- and HrCAO- overexpressing tobaccos.

A laboratory study of vertical migration

1955 ◽  
Vol 144 (916) ◽  
pp. 329-354 ◽  
Keyword(s):  
Light Intensity ◽  
Vertical Migration ◽  
Time Course ◽  
Tap Water ◽  
Low Light ◽  
Overhead Light ◽  
Light Intensities ◽  
Orientation Response ◽  
Reduced Light ◽  
Characteristic Maximum

In a tank filled with a suspension of indian ink in tap water, a population of Daphnia magna will undergo a complete cycle of vertical migration when an overhead light source is cycli­cally varied in intensity. A ‘dawn rise’ to the surface at low intensity is followed by the descent of the animals to a characteristic maximum depth. The animals rise to the surface again as the light decreases, and finally show a typical midnight sinking. The light intensities at the level of the animals in this experiment are of the same order as those which have been reported in field observations; the time course of the movement also repeats the natural conditions in the field. The process is independent of the duration of the cycle and is related only to the variation in overhead light intensity. At low light intensity the movement of the animal is determined solely by positive photo-kinesis; the dawn rise is a manifestation of this, and is independent of the direction of the light. At high light intensities there is an orientation response which is superimposed upon an alternating positive (photokinetic) phase and a negative phase during which movement is inhibited. The fully oriented animal shows a special type of positive and negative phototaxis, moving towards the light at reduced light intensities and away from it when the light intensity is increased. In this condition it follows a zone of optimum light intensity with some exactness. Experiments show that an animal in this fully oriented condition will respond to the slow changes of intensity characteristic of the diurnal cycle, while being little affected by tran­sient changes of considerable magnitude.

Pycnidium production by Botryodiplodia theobromae. I. The relation of light to the induction of pycnidia

1969 ◽  
Vol 47 (7) ◽  
pp. 1153-1156 ◽  
Author(s):  
J. A. Ekundayo ◽  
R. H. Haskins
Keyword(s):  
Light Intensity ◽  
Ultraviolet Radiation ◽  
Exposure Period ◽  
Fluorescent Light ◽  
Botryodiplodia Theobromae ◽  
Continuous Irradiation ◽  
Long Wave ◽  
Light Intensities ◽  
Glass Color ◽  
Color Filters

Cultures of Botryodiplodia theobromae Pat. produced pycnidia abundantly on several media under continuous irradiation with fluorescent light. The fungus did not sporulate when grown in darkness. Irradiation of cultures with a light intensity of 15 foot-candles for 4 days was sufficient to stimulate pycnidial production, but for appreciable sporulation to occur over the same exposure period, higher light intensities are required. Irradiation of cultures through glass color filters showed that long-wave ultraviolet radiation stimulated sporulation.

Sensory Behaviour in Dictyostelium Discoideum Slugs: Phototaxis and Thermotaxis are not Mediated by a Change in Slug Speed

1982 ◽  
Vol 54 (1) ◽  
pp. 329-339
Author(s):  
ELIZABETH SMITH ◽  
PAUL R. FISHER ◽  
WARWICK N. GRANT ◽  
KEITH L. WILLIAMS
Keyword(s):  
Molecular Weight ◽  
Temperature Gradient ◽  
Light Intensity ◽  
Dictyostelium Discoideum ◽  
Low Molecular Weight ◽  
Light Intensities ◽  
Slug Movement

The speed of sustained migration of Dictyostelium discoideum slugs was similar in a temperature gradient and at different light intensities, including a light intensity sufficient to cause significant disorientation of slugs. No change was observed in slug speed in the presence of high levels of Slug Turning Factor (STF), a low molecular weight compound through which phototaxis and thermotaxis are mediated. Thus orientation of D. discoideum slugs is not mediated by a sustained changed in slug speed and we propose that slug movement is not directly coupled to tactic responses. Slug speed depended on the size, age and genotype of slugs as well as the nature of the substratum (charcoal-containing water agar versus water agar).

scholarly journals Effects of light intensity and temperature on Cylindrospermopsis raciborskii (Cyanobacteria) with straight and coiled trichomes: growth rate and morphology

2012 ◽  
Vol 72 (2) ◽  
pp. 343-351 ◽  
Author(s):  
MC. Bittencourt-Oliveira ◽  
B. Buch ◽  
TC. Hereman ◽  
JDT. Arruda-Neto ◽  
AN. Moura ◽  
...  
Keyword(s):  
Growth Rate ◽  
Light Intensity ◽  
Morphological Changes ◽  
Population Control ◽  
Distinct Species ◽  
Cylindrospermopsis Raciborskii ◽  
Climatic Chamber ◽  
Light Intensities ◽  
Different Temperatures ◽  
Lower Temperature

Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju (Ordem Nostocales) is one of the most troublesome bloom-forming species in Brazil. Understanding the population dynamics of the different morphotypes of C. raciborskii (straight and coiled) could assist in the prediction of favourable conditions for the proliferation of this potentially toxin-producing species. The aim of the present study was to assess the effects of two different light intensities and temperatures on the growth rate and morphology of the trichomes of the straight and coiled morphotypes. For such, two non-toxin producing strains of C. raciborskii were used - one with a coiled trichome (ITEP31) and another with a straight trichome (ITEP28). The strains were cultured in BG-11 medium in a climatic chamber under controlled conditions. Two light intensities (30 and 90 µmol.m-2.s-1 ) were combined at temperatures of 21 and 31 °C and the growth rate and morphological changes were analysed. The morphotypes responded differently to the different temperatures and light intensities. Both strains exhibited faster growth velocities when submitted to higher light intensity and temperature. The lower temperature and higher luminosity hampered the development of both strains. Variations in cellular morphology and an absence of akinetes in both strains were related to the lower temperature (21 °C). The coiled morphotype demonstrated considerable phenotype plasticity, changing the morphology of trichome throughout its growth curve. Although molecular analysis does not sustain the separation of the morphotypes as distinct species, their different eco-physiological responses should be considered further knowledge of extreme importance for the population control of these potentially toxic organisms.

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