Age-related changes in the visual pigments of the white sturgeon (Acipenser transmontanus)

1993 ◽  
Vol 71 (8) ◽  
pp. 1552-1557 ◽  
Author(s):  
E. R. Loew ◽  
A. J. Sillman

Using in situ microspectrophotometry, the spectral absorbance characteristics of the photoreceptors in the retinas of larval, juvenile, and adult white sturgeon (Acipenser transmontanus) were determined. The adult has one type of rod, containing a visual pigment with maximum spectral absorbance (λmax) near 540 nm. There are three types of cones, morphologically identical but distinguished from one another by containing either a blue-sensitive (λmax 464 nm), green-sensitive (λmax 531 nm), or red-sensitive (λmax 605 nm) visual pigment. Juvenile sturgeon have visual pigments similar to those of the adult. However, no evidence could be found for the presence of either blue-sensitive or red-sensitive cones in larval white sturgeon through the age of 10 weeks. Larval sturgeon up to about 10 weeks yielded only green-sensitive rods and cones. The absence of red-sensitive cones in the larvae, and their presence in older fish, was confirmed by the use of 4,4′-diisothiocyanato-stilbene-2,2′-disulfonic acid, a fluorescent substance that binds selectively to photoreceptors sensitive to long-wavelength light. Regardless of age, all visual pigments are based on vitamin A2. Also regardless of age, white sturgeon retinas yielded no evidence for the presence of photoreceptors sensitive to ultraviolet light.

1990 ◽  
Vol 68 (7) ◽  
pp. 1544-1551 ◽  
Author(s):  
A. J. Sillman ◽  
M. D. Spanfelner ◽  
E. R. Loew

The photoreceptors in the retina of the white sturgeon, Acipenser transmontanus (Chondrostei), were studied by means of scanning electron microscopy, in situ microspectrophotometry, and spectrophotometric analysis of visual pigment extracts. The white sturgeon retina is simple in that it contains only two morphologically distinct photoreceptors. The retina is dominated by rods with large outer segments, but there is a substantial population (40%) of single cones. Evidence was found for only one rod visual pigment and one cone visual pigment. Peak spectral absorbance (λmax) of the rod pigment is near 539 nm, whereas λmax of the cone pigment is near 605 nm. Both visual pigments are porphyropsin types with chromophores based on vitamin A2. No detectable rhodopsin based on vitamin A1 is ever present, regardless of season or light regimen. The results are discussed in terms of the sturgeon's behavior, as well as the implications for the evolution of color vision.


2007 ◽  
Vol 85 (4) ◽  
pp. 584-587 ◽  
Author(s):  
A.J. Sillman ◽  
E.K. Ong ◽  
E.R. Loew

Lake sturgeon ( Acipenser fulvescens Rafinesque, 1817) photoreceptors were studied with scanning electron microscopy and microspectrophotometry. The retina contains both rods and cones, with cones estimated composing about 30% of the photoreceptor population. Only large single cones were identified and they are similar to those found in other species of the order Acipenseriformes. The rods are large, with long, broad outer segments, and are similar to the dominant rod found in other sturgeons and the North American paddlefish ( Polyodon spathula (Walbaum, 1792)). Mean (SD) rod packing density at 22 624 ± 3 509 rods/mm2 is low compared with those of other animals that function primarily in dim light. The visual pigment of the rods has a mean (SD) peak absorbance (λmax) at 541 ± 2 nm. Three different cone populations were identified: a long wavelength sensitive cone containing a visual pigment with λmax at 619 ± 3 nm; middle wavelength sensitive cone with λmax at 538 ± 1 nm; and short wavelength sensitive cone with λmax at 448 ± 1 nm. All the visual pigments are based on the vitamin A2 chromophore.


1995 ◽  
Vol 73 (4) ◽  
pp. 805-809 ◽  
Author(s):  
A. J. Sillman ◽  
M. E. Sorsky ◽  
E. R. Loew

The visual pigments of the anadromous white sturgeon (Acipenser transmontanus) taken from relatively saline estuarine water were characterized by means of in situ microspectrophotometry and partial bleaching analysis of a digitonin extract. The three cone pigments (λmax = 605, 539, and ca. 460 nm) and one rod pigment (λmax = 541 nm) of the wild sturgeon are the same as those of cultured sturgeon that spend their entire lives in fresh water. All the visual pigments incorporate a chromophore based on vitamin A2. Unlike other anadromous fishes during the "saline phase," the white sturgeon shows no evidence of the presence of any vitamin A1 based visual pigment in the retina.


2009 ◽  
Vol 26 (3) ◽  
pp. 267-274 ◽  
Author(s):  
TOMOKI ISAYAMA ◽  
S.L. McCABE ENGLAND ◽  
R.K. CROUCH ◽  
A.L. ZIMMERMAN ◽  
C.L. MAKINO

AbstractVision begins with photoisomerization of 11-cis retinal to the all-trans conformation within the chromophore-binding pocket of opsin, leading to activation of a biochemical cascade. Release of all-trans retinal from the binding pocket curtails but does not fully quench the ability of opsin to activate transducin. All-trans retinal and some other analogs, such as β-ionone, enhance opsin’s activity, presumably on binding the empty chromophore-binding pocket. By recording from isolated salamander photoreceptors and from patches of rod outer segment membrane, we now show that high concentrations of β-ionone suppressed circulating current in dark-adapted green-sensitive rods by inhibiting the cyclic nucleotide-gated channels. There were also decreases in circulating current and flash sensitivity, and accelerated flash response kinetics in dark-adapted blue-sensitive (BS) rods and cones, and in ultraviolet-sensitive cones, at concentrations too low to inhibit the channels. These effects persisted in BS rods even after incubation with 9-cis retinal to ensure complete regeneration of their visual pigment. After long exposures to high concentrations of β-ionone, recovery was incomplete unless 9-cis retinal was given, indicating that visual pigment had been bleached. Therefore, we propose that β-ionone activates and bleaches some types of visual pigments, mimicking the effects of light.


1985 ◽  
Vol 42 (7) ◽  
pp. 1321-1325 ◽  
Author(s):  
R. P. Hedrick ◽  
J. Speas ◽  
M. L. Kent ◽  
T. McDowell

Juvenile white sturgeon, Acipenser transmontanus, suffering from a chronic mortality had enlarged nuclei particularly in the epithelium of the straight intestine and spiral valve. These nuclei were often five times larger than those of uninfected cells and contained numerous virus particles with an average diameter of 74 nm. Although nuclear changes induced by the virus are similar to those described for certain members of the Herpesviridae, the virion morphology and absence of an envelope were, however, more characteristic of the Adenoviridae. Attempts to isolate the virus using established cell lines from selected freshwater fish and two lines recently developed from white sturgeon were unsuccessful. Nuclear enlargement indicating virus infection was, however, observed in juvenile sturgeon receiving intraperitoneal injections of homogenates of viscera from infected fish.


1999 ◽  
Vol 202 (14) ◽  
pp. 1931-1938 ◽  
Author(s):  
A.J. Sillman ◽  
J.K. Carver ◽  
E.R. Loew

The photoreceptors and visual pigments of Python regius were studied using microspectrophotometry and scanning electron microscopy. The retina contains rods and cones, with rods constituting at least 90 % of the photoreceptor population. The rods are of a single type with long, narrow outer segments and are tightly packed. The wavelength of maximum absorbance (λ max) of the visual pigment in the rods is in the region of 494 nm. Two distinct types of cone are present. The most common cone, with a stout but stubby outer segment, contains a visual pigment with λ max at approximately 551 nm. A relatively rare cone, with a long, slender outer segment, contains an ultraviolet-sensitive visual pigment with λ max at approximately 360 nm. All the visual pigments have chromophores based on vitamin A1. The results are discussed in relation to the behavior of P. regius.


2017 ◽  
Vol 124 (1) ◽  
pp. 11-20 ◽  
Author(s):  
E Soto ◽  
C Richey ◽  
B Stevens ◽  
S Yun ◽  
K Kenelty ◽  
...  

1998 ◽  
Vol 33 (1) ◽  
pp. 95-110 ◽  
Author(s):  
W.R. Bennett ◽  
A.P. Farrell

Abstract The primary goal of this study was to investigate the possibility of using early life stages of white sturgeon (Acipenser transmontanus) (eggs, larvae and fry) as a species relevant to the Fraser River, B.C., for the acute and sublethal toxico-logical testing of forest industry effluents. Here we report the first successful acute toxicity tests for 8-day-old larvae and 42-day-old fry exposed to several chemicals known to be released into the Fraser River (i.e., 6 monochlorovanillin [6 MVAN], 4,5 dichloroguaiacol [4,5 DCG], 4,5 dichlorocatechol [4,5 DCAT], pentachlorophenol [PCP], and didecyldimethylammonium chloride [DDAC]). In most cases, white sturgeon fry were at the lower end of the range for acute toxicity values for chlorinated phenolic compounds, when compared with other juvenile fish species, and they were extremely sensitive to DDAC. The larval stage was usually more sensitive than the fry stage. Acute toxicity tests with fertilized eggs were unsuccessful. A postexposure growth study was inconclusive because neither control nor toxicant-exposed larvae and fry withstood the additional handling used for measuring body mass. At 62-days-old, fry were more tolerant of handling. This allowed measurement of their swimming performance. Although we have concerns about the reliability of using larvae for acute toxicity testing at this time, 60-day-old white sturgeon fry would appear to be both a sensitive and relevant species for assessing environmental impacts relevant to the Fraser River.


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