Color Zone Map in Peripheral Vision at Various Illuminance Levels

We measured the entire region of mesopic and photopic vision to determine the color zone covering the visual field with unique red, yellow, green, and blue hue components. Eight kinds of test stimuli in the natural color system (NCS) color notation system were used. These stimuli were presented at horizontal and vertical meridians, and at meridians inclined at 45° angles. The illuminance level was set at six levels: 0.01 lx-1000 lx. The evaluation method measured chromatic, white, and black components as well as the hue component of the stimuli. Results show that the color zone of the retina extended further into the periphery with increasing illuminance; the response of opponent colors y-b was shown to be greater than that of the opponent colors r-g.     

PHOTOREACTIVATION ASSOCIATED WITH CHROMOSOMAL ABNORMALITY IN SEA URCHIN EGGS FERTILIZED WITH ULTRAVIOLET-IRRADIATED SPERM

Abstract— As a model for studies involving biologic systems, rates of hematoporphyrin and protopor-phyrin-sensitized photooxidation of tryptophan were measured in water-methanol mixtures. Absorption and fluorescence-emission spectra associated with solutions of porphyrins in different water-methano! mixtures were also examined. The optimal rate of photooxidation by hematoporphyrin occurred in 30% methanol; by protoporphyrin, in 60% methanol. Absorption spectra were examined to characterize dispersion of hematoporphyrin into monomeric form in 90% methanol, and the dimer formation which predominates in 30% methanol. With the more hydrophobic protoporphyrin, an absorption spectrum characteristic of drug monomer was seen in 100% methanol, a dimer spectrum was observed in 60% methanol. At methanol concentrations < 60%, we observed impaired photooxidation and another alteration in the absorption pattern apparently reflecting drug aggregation beyond the dimer stage. Fluorescence emission maxima of both porphyrins were blue-shifted with increasing solvent dielectric constant, but an additional blue shift was detected in an aqueous environment which was apparently related to porphyrin aggregation. Absorption and fluorescence-emission spectra appear helpful for characterizing environmental determinants of porphyrin-sensitized photooxidation.     

Spacer effect of appended moieties for molecular recognition in doubly-sodium anthranilate modified γ-cyclodextrin

-Cyclodextrin with two sodium anthranilate moieties (1) has been prepared as a sensor for detecting organic compounds including terpenoids and steroids. Compound1 shows a pure monomer fluorescence whose intensity is increased or decreased upon addition of the guest species examined. In this system, the sodium anthranilate moieties act either as a spacer, which enables the cyclodextrin to form a 1:1 host-guest complex by narrowing the -cyclodextrin cavity, or as a hydrophobic cap.1 recognizes steroids with much higher sensitivity than terpenoids, in which the appended moieties act as a hydrophobic cap for terpenoids and a spacer for steroids, respectively.     

Identification and determination of sulphamethazine and N4-acetylsulphamethazine in meat by high-performance liquid chromatography with photodiode-array detection

A simple and selective method for the determination of sulphamethazine (SMT) and its metabolite, N4-acetylsulphamethazine (N4-AcSMT), in meat by high-performance liquid chromatography (HPLC) with photodiode-array detection was developed. The drugs were extracted from meat with 0.2% metaphosphoric acid-methanol (6:4), followed by a Bond-Elut C18 clean-up procedure. The HPLC separation was carried out on a Supersphere RP-18e column (125 X 4.0 mm I.D.) using 0.05 M sodium dihydrogenphosphate (pH 4.5)-acetonitrile (8:2) as the mobile phase at a flow-rate of 0.5 ml/min, and monitored with a photodiode-array detector. The recoveries of SMT and N4-AcSMT from meat fortified at 0.5 micrograms/g were 90.1-93.3 and 93.0-94.4%, respectively, with coefficients of variation of 1.9-3.2 and 1.5-2.7%. The limits of detection were 0.02 micrograms/g for each drug. SMT was found in ten samples of imported meat (12.5%) at levels ranging from 0.05 to 1.05 micrograms/g.     

Spectrofluorimetric assay for acyl CoA-cholesterol acyltransferase

A sensitive assay for acyl CoA-cholesterol acyltransferase (EC 2.3.1.26) in rat liver microsomal and mitochondrial preparations is described. The lowered cholesterol concentration in the enzyme reaction with oleoyl CoA is determined spectrofluorimetrically by using the cholesterol oxidase/peroxidase/p-hydroxyphenylpropionic acid system. The assay requires as little as 20 μg of protein in the enzyme preparation.     

Dansyl-Modified γ-Cyclodextrin as a fluorescent sensor for molecular recognition

The crystal structure of thiamine iodide sesquihydrate has been determined by X-ray diffraction methods as a host-guest model for coenzyme-substrate interactions. The asymmetric unit contains two chemical units. Both the thiamine molecules A and B, which are crystallographically independent, assume the usualF conformation and have a disordered hydroxyethyl side chain. An iodide anion (or a water molecule) bridges the pyrimidine and thiazolium rings of molecule A (or B) by forming a hydrogen bond with the amino group and an electrostatic contact with the thiazolium ring to stabilize the molecular conformation. In the crystal the thiamine molecules self-associate to form a pipe-like polymeric structure, in which four thiamine hosts surround an iodide guest and hold it through C(2)-H...I hydrogen bonds and thiazolium...I electrostatic interactions. Crystal data: C₁₂H₁₇N₄OS⁺·I^– · 1.5 H₂O, monoclinic,P2₁/c, a=12.585(2), b=25.303(5), c=12.030(2) Å, =115.15(1)°,V=3468(1) ų,Z=8,D _c=1.606 g cm^–3,R=0.045 for 3328 observed reflections. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP. 82156 (13 pages).     

Negative ion mass spectra of chlorine-containing molecules

The negative ion mass spectra of chlorine-containing molecules have been measured using a double focusing mass spectrometer with a photographic plate detector. The formulae of the negative ions not previously assigned using an electron multiplier detector have now been assigned.     

Stimulatory effect of red light on starch accumulation in a marine green alga,chlamydomonas sp. strain MGA161

A marine green alga,Chlamydomonas sp. strain MGA161 was cultivated under illumination of red and white lights. The growth rate under red light illumination was almost the same as that in the basic conditions under white light illumination, but red light-grown cells accumulated almost twice as much starch as white light-grown cells. Although there was a slight decrease in carbonic anhydrase activity, red light-illuminated cells had almost 2.3 times the fructose-l,6-diphos-phatase activity of white light-illuminated cells. Red light might stimulate starch accumulation by increasing the amounts of enzymes related to carbon fixation through the phytochrome system. Cells grown under red light degraded 1.6 times as much starch and produced 1.7 times as much hydrogen and 1.6 times as much ethanol compared with cells grown under white light during 12 h of dark anaerobic fermentation.