Electroretinographic Determination of Spectral Sensitivity in Albino and Pigmented Brook Trout (Salvelinus fontinalis, Mitchill)

1971 ◽  
Vol 49 (12) ◽  
pp. 1030-1037 ◽  
Author(s):  
H. Kobayashi ◽  
M. A. Ali
Keyword(s):  
Absorption Spectrum ◽  
Spectral Sensitivity ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Narrow Band ◽  
Visible Spectrum ◽  
The Difference

A technique for recording electroretinograms from the unpunctured eyes in situ of living, anesthetized fish is described. This technique permits the use of the same fish in a number of experiments over a period of weeks, months, or years. Using this technique the spectral sensitivity of dark-adapted (scotopic) and light-adapted (photopic) fish was measured at 13 bands of the visible spectrum. The scotopic curves of albino and pigmented trout thus obtained in the winter have their maxima around 525 nm which differ from that of the absorption spectrum of the scotopic pigment in situ and in vitro of older fish obtained in the summer. The photopic curve of the pigmented fish is a broad one with humps around 425 nm, 545 nm, and 595 nm. The albino's curve has a relatively narrow band with a peak around 630 nm and a shoulder at about 550 nm. The difference between the shapes of the two curves may be ascribed to the increase in the intensity of light of longer wavelengths within the eyeball of the albino, due to reflection from blood vessels and sclera caused by the absence of pigmentation.

scholarly journals Analyzing Satellite Ocean Color Match-Up Protocols Using the Satellite Validation Navy Tool (SAVANT) at MOBY and Two AERONET-OC Sites

2021 ◽  
Vol 13 (14) ◽  
pp. 2673
Author(s):  
Adam Lawson ◽  
Jennifer Bowers ◽  
Sherwin Ladner ◽  
Richard Crout ◽  
Christopher Wood ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Ocean Color ◽  
Visible Spectrum ◽  
Ground Truth ◽  
Naval Research ◽  
Satellite Validation ◽  
The Difference ◽  
Stability And Accuracy ◽  
Satellite Ocean Color

The satellite validation navy tool (SAVANT) was developed by the Naval Research Laboratory to help facilitate the assessment of the stability and accuracy of ocean color satellites, using numerous ground truth (in situ) platforms around the globe and support methods for match-up protocols. The effects of varying spatial constraints with permissive and strict protocols on match-up uncertainty are evaluated, in an attempt to establish an optimal satellite ocean color calibration and validation (cal/val) match-up protocol. This allows users to evaluate the accuracy of ocean color sensors compared to specific ground truth sites that provide continuous data. Various match-up constraints may be adjusted, allowing for varied evaluations of their effects on match-up data. The results include the following: (a) the difference between aerosol robotic network ocean color (AERONET-OC) and marine optical Buoy (MOBY) evaluations; (b) the differences across the visible spectrum for various water types; (c) spatial differences and the size of satellite area chosen for comparison; and (d) temporal differences in optically complex water. The match-up uncertainty analysis was performed using Suomi National Polar-orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) SNPP data at the AERONET-OC sites and the MOBY site. It was found that the more permissive constraint sets allow for a higher number of match-ups and a more comprehensive representation of the conditions, while the restrictive constraints provide better statistical match-ups between in situ and satellite sensors.

Determination of mosquito bloodmeal pH in situ by ion-selective microelectrode measurement: implications for the regulation of malarial gametogenesis

Parasitology ◽  
2000 ◽  
Vol 120 (6) ◽  
pp. 547-551 ◽  
Author(s):  
O. BILLKER ◽  
A. J. MILLER ◽  
R. E. SINDEN
Keyword(s):  
Xanthurenic Acid ◽  
Mosquito Vector ◽  
Dependent Manner ◽  
Ph Increase ◽  
Ph Range ◽  
Dose Dependent

Malarial gametocytes circulate in the peripheral blood of the vertebrate host as developmentally arrested intra-erythrocytic cells, which only resume development into gametes when ingested into the bloodmeal of the female mosquito vector. The ensuing development encompasses sexual reproduction and mediates parasite transmission to the insect. In vitro the induction of gametogenesis requires a drop in temperature and either a pH increase from physiological blood pH (ca pH 7·4) to about pH 8·0, or the presence of a gametocyte-activating factor recently identified as xanthurenic acid (XA). However, it is unclear whether either the pH increase or XA act as natural triggers in the mosquito bloodmeal. We here use pH-sensitive microelectrodes to determine bloodmeal pH in intact mosquitoes. Measurements taken in the first 30 min after ingestion, when malarial gametogenesis is induced in vivo, revealed small pH increases from 7·40 (mouse blood) to 7·52 in Aedes aegypti and to 7·58 in Anophěles stephensi. However, bloodmeal pH was clearly suboptimal if compared to values required to induce gametogenesis in vitro. Xanthurenic acid is shown to extend the pH-range of exflagellation in vitro in a dose-dependent manner to values that we have observed in the bloodmeal, suggesting that in vivo malarial gametogenesis could be further regulated by both these factors.

Potential of solubility, enzymatic methods and NIRS to predict in situ rumen escape protein

1997 ◽  
Vol 45 (2) ◽  
pp. 291-306 ◽  
Author(s):  
J.L. De Boever ◽  
B.G. Cottyn ◽  
J.M. Vanacker ◽  
C.V. Boucque
Keyword(s):  
Phosphate Buffer ◽  
Near Infrared ◽  
Streptomyces Griseus ◽  
Maize Silage ◽  
Near Infrared Reflectance ◽  
In Vitro Method ◽  
Rumen Degradation ◽  
The Difference

The percentage of feed protein escaping rumen degradation was measured by the in situ method (%EPsitu) for 29 compound feeds, untreated and formaldehyde-treated soyabean meal and 12 forages: 3 grass silages, 2 maize silages, fresh grass, grass hay, fodder beets, fresh potatoes, ensiled beet pulp, chopped ear-maize silage and brewers' grains. Loss of particles through bag pores was determined by the difference between the washable fraction (W) and the fraction soluble in borate-phosphate buffer at pH 6.7 (S). W - S was most pronounced for compound feeds (on average 14.4 percentage units), for brewers' grains and maize silages. A correction of %EPsitu, assuming that W - S degrades like the potentially degradable fraction, was not appropriate. Solubility in borate-phosphate buffer after 1 h, enzymic degradability by protease from Streptomyces griseus or ficin after 1, 6 and 24 h and near infrared reflectance spectroscopy (NIRS) (for compound feeds alone) were examined as a routine method to predict %EPsitu. With the buffer and S. griseus the effect of pH (6.7 vs. 8.0) and at pH 8.0 the effect of amount of substrate (500-mg sample vs. 20 mg N) were tested. With ficin, 500-mg samples were incubated at pH 6.7. Predictions were better when compound feeds and forages were considered separately. However, the best in vitro method was different for the 2 feed categories, being solubility in buffer for the compound feeds and enzymic degradation of a constant amount of protein with S. griseus at pH 8.0 for forages. NIRS showed potential to predict %EPsitu of compound feeds, but needs more reference samples. The Dutch feed tables appeared more accurate than the best in vitro method for compound feeds, but was too inaccurate for some forages like fodder beets, maize silage and ear-maize silage.

Removal of Follicle Wall Components from Ovarian Oocytes of the Brook Trout, Salvelinus fontinalis

1985 ◽  
Vol 42 (12) ◽  
pp. 2053-2058 ◽  
Author(s):  
Charles A. Lessman ◽  
Soosamma Kavumpurath ◽  
Hamid R. Habibi
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Ovarian Tissue ◽  
Meiotic Maturation ◽  
Cell Surfaces ◽  
Maturation In Vitro ◽  
Free Media ◽  
Brook Trout Oocytes ◽  
Wall Components

Fully grown brook trout (Salvelinus fontinalis) ovarian follicles, preincubated in Ca2+-free media, were dissected from other ovarian tissue by use of watchmaker forceps. Manual defolliculation and further Ca2+-free treatments were used to obtain oocytes freed of one or more follicular investments. Combinations of these treatments ultimately resulted in oocytes denuded of somatic cells as demonstrated by scanning electron microscopy. Mechanically denuded brook trout oocytes maintained the ability to undergo progestogen-induced meiotic maturation in vitro. This technique, which avoids use of enzymes that may alter cell surfaces, provides a useful system for the study of interactions between follicle wall components and the oocyte during hormonally induced meiotic maturation in vitro.

In situ Bioassays of Brook Trout (Salvelinus fontinalis) and Blacknose Dace (Rhinichthys atratulus) in Adirondack Streams Affected by Episodic Acidification

1993 ◽  
Vol 50 (5) ◽  
pp. 902-912 ◽  
Author(s):  
Howard A. Simonin ◽  
Walter A. Kretser ◽  
Dale W. Bath ◽  
Mark Olson ◽  
James Gallagher
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Fish Mortality ◽  
Variable Model ◽  
Poor Water Quality ◽  
Rhinichthys Atratulus ◽  
Blacknose Dace ◽  
In Situ Bioassays ◽  
Precipitation Events

In situ bioassays were conducted using native Adirondack brook trout (Salvelinus fontinalis) and blacknose dace (Rhinichthys atratulus) in four headwater streams. Conductivity, pH, temperature, and stage height were monitored continuously, and water samples for laboratory analysis were collected during hydrologic episodes. Fish survived well during baseflow conditions, but during periods of spring snowmelt or large precipitation events, survival was poor. Blacknose dace were more sensitive than brook trout, and mortality was best correlated with the log of median inorganic monomeric aluminum (Alim) concentration. Brook trout mortality was best correlated with a two-variable model that included dissolved organic carbon (DOC) and a concentration–duration variable (median Alim during the episode times the duration of the episode). Brook trout mortality was inversely correlated with DOC. Bioassay fish that had been in the streams 15–24 d survived episodes better than fish that had either not become acclimatized or recovered from handling. Duration of exposure to acidic episodes was critical. Extended periods of poor water quality resulted in fish mortality and may be more important to native populations than short acidic episodes.

scholarly journals Regulation of platelet AMP deaminase activity in situ

1990 ◽  
Vol 265 (1) ◽  
pp. 267-275 ◽  
Author(s):  
A J M Verhoeven ◽  
J Marszalek ◽  
H Holmsen
Keyword(s):  
Human Platelets ◽  
Partial Purification ◽  
Amp Deaminase ◽  
H2o2 Treatment ◽  
Half Saturation Constant ◽  
Intracellular Phosphate ◽  
The Difference ◽  
Main Regulator

The regulation of platelet AMP deaminase activity by ATP, GTP and phosphate was studied in human platelets in situ, and in vitro after partial purification. In intact platelets, a similar 50% decrease in cytosolic ATP was induced by either glucose starvation or treatment with H2O2. During starvation, AMP deaminase was in the inhibited state, as ATP consumption was mostly balanced by the accumulation of AMP. During H2O2 treatment, however, the enzyme was in the stimulated state, as the AMP formed was almost completely deaminated to IMP. Cytosolic GTP fell by 40-50% in both starvation and H2O2 treatment. In contrast, intracellular phosphate was 4-5-fold higher in starved than in H2O2-treated cells. These data point to phosphate as the main regulator of AMP deaminase activity in situ. This conclusion was verified by kinetic analysis of partially purified AMP deaminase. At near-physiological concentrations of MgATP, MgGTP and phosphate, the S0.5 (substrate half-saturation constant) for AMP was 0.35 mM. Half-maximal stimulation by MgATP occurred at a concn. between 2 and 3 mM. This stimulation was antagonized by the inhibitory effects of phosphate (IC50 = 2.0 mM) and MgGTP (IC50 = 0.2-0.3 mM), which acted in synergism (IC50 is the concentration causing 50% inhibition). We conclude that the difference in adenylate catabolism between starved and H2O2-treated platelets is due to the distinct phosphate concentrations. During starvation, refeeding and H2O2 treatment, the values of the adenylate charge and the phosphorylation potential were kept closely co-ordinated, which may be effected by AMP deaminase.

Hard-tissue Substrates for Evaluation of Cariogenic and Anti-cariogenic Activity in situ

1992 ◽  
Vol 71 (3_suppl) ◽  
pp. 913-919 ◽  
Author(s):  
J.R. Mellberg
Keyword(s):  
Root Surface ◽  
Hard Tissue ◽  
Suitable Alternative ◽  
Human Enamel ◽  
Human Dentin ◽  
Bovine Enamel ◽  
Root Surface Caries

Hard-tissue substrates include primarily human and bovine enamel and human dentin. They have been used for in situ studies in a natural or sound condition, as well as flattened or containing an in vitro-formed caries-like lesion. Human enamel and dentin are generally the substrates of choice for studies of coronal and root-surface caries, respectively, but bovine enamel appears to offer a suitable alternative for many studies of enamel caries. Substrates with caries-like lesions will respond more rapidly to changes in the intra-oral mineral equilibrium and will allow both demineralization and remineralization to be determined. Findings from some studies suggest that caries-like lesions may respond somewhat differently, depending upon the degree of mineralization of the surface layer. Because in vitro findings with dentin show it to be significantly more soluble in acid than enamel, results from a study that used dentin may not be directly applicable to enamel. Both enamel and dentin substrates can be used in thin-section models. Hard-tissue substrates can also differ, depending upon their intra-oral location. Locations that result in the accumulation of plaque will behave differently from those that are plaque-free. So that plaque would accumulate, substrates have been placed approximally, beneath a fabric or steel mesh, in a protected trough, beneath a metal band or within a depression on the buccal surface. For studies requiring a determination of both demineralization and remineralization, human enamel or dentin containing a surface-softened caries-like lesion and covered with a uniform natural plaque are the substrates of choice.

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