Showing papers by "Jagiellonian University published in 1987"
TL;DR: Evidence for metal‐ion dependent formation of hydroxyl radicals during photooxidation of melanin pigments was obtained using electron spin resonance‐spin trapping procedures and superoxide dismutase increased the rate of formation of hydroxy radicals in the system.
Abstract: The hydrogen peroxide produced during photolysis of melanin pigments has been measured using an oxidase electrode. The photooxidation has been shown to occur via the superoxide intermediate. In the presence of superoxide dismutase the rate of photo-induced production of hydrogen peroxide is increased, reflecting the ability of melanin to scavenge superoxide radicals. Evidence for metal-ion dependent formation of hydroxyl radicals during photooxidation of melanin pigments was obtained using electron spin resonance-spin trapping procedures. Superoxide dismutase increased the rate of formation of hydroxyl radicals in the system. Mechanisms of metal ion-induced production of hydroxyl radicals during photolysis of melanin pigments are discussed.
179 citations
TL;DR: In this article, it is shown that the ability of workers to perceive multiple mating allows the queen to prevent them from producing their own male progeny is an adaptive function of the queen.
167 citations
TL;DR: A model predicting optimal timing of growth and reproduction in perennial species with indeterminate growth living in a seasonal environment, is presented and shows that the optimal fraction of growing season devoted to growth decreases with increasing individual age and size, which leads to S-shaped growth curves.
Abstract: A model predicting optimal timing of growth and reproduction in perennial species with indeterminate growth living in a seasonal environment, is presented. According to the model, the optimal fraction of growing season devoted to growth decreases with increasing individual age and size, which leads to S-shaped growth curves. Winter mortality seems to be a crucial factor affecting the timing of growth and reproduction, under the same function describing the dependence of growth rate and reproductive rate on body size. When winter mortality is heavy, it is often optimal to start reproducing in the first year, and to devote a large proportion of the subsequent years to reproduction, thus leading to small adult body sizes. The model has been applied to two species of mollusc and one species of fish. The model predictions fit well to the field data for these three species.
159 citations
TL;DR: A model predicting optimal age and size at maturity is presented, exploring the conflict between growth and energy allocation to reproduction and sexual size dimorphism, resulting from different optimal age at maturity for either sex.
Abstract: A model predicting optimal age and size at maturity is presented, exploring the conflict between growth and energy allocation to reproduction. According to the model, the factors promoting delayed maturity and large adult body size are as follows: (1) high rate of somatic growth, (2) high percentage increase in reproductive rate with body size increase, (3) long life expectancy at maturity for annuals or large number of expected productive days (when either growth or reproduction is possible) for perennials with growth ceasing at maturity, (4) life expectancy increasing with body size. All these factors are combined in the mathematical formula predicting optimal age and size at maturity, which allows for quantitative predictions. The optimal schedule of growth and reproduction may be achieved by natural selection, developmental plasticity, or when one species replaces another. Sexual size dimorphism is also discussed, resulting from different optimal age at maturity for either sex.
143 citations
TL;DR: The results favour a presynaptic location of the mechanisms of the paired-pulse facilitation and suggest increases in the average of transmitter quanta released by presyaptic volley as well as increases inThe amount of transmitter in each quantum.
130 citations
TL;DR: An electron paramagnetic resonance image was measured for the first time from in vivo field gradient spectra of a living murine tumor using the paramagnetic nitroxide imaging agent 3‐carboxamido‐2,2,5,5‐tetramethylpyrroline‐l‐oxyl injected into the tail vein.
Abstract: An electron paramagnetic resonance image was measured for the first time from in vivo field gradient spectra of a living murine tumor (Cloudman S-91 melanoma in the tail of a DBA-2J mouse) using the paramagnetic nitroxide imaging agent 3-carboxamido-2,2,5,5-tetramethylpyrroline-1-oxyl injected into the tail vein. The experiments were accomplished at L-band frequency (1.55 GHz) with a single-turn flat-loop coil. A cross-sectional image was obtained perpendicular to the tail axis, which clearly distinguished features to the submillimeter resolution level.
115 citations
TL;DR: Results do not support the 'aerobic capacity' model of the origin of endothermy, and the mass exponent of the allometric regression equation for maximum metabolic rate is significantly higher than that for BMR.
77 citations
Journal Article•
TL;DR: The results suggest that interleukin 1 or tumour necrosis factor are not likely the principal mediators responsible for the direct stimulation of normal rat hepatocytes to acute phase protein synthesis.
Abstract: Albumin, fibrinogen, alpha 1-acid glycoprotein and cysteine proteinase inhibitor were determined by electroimmunoassay in the media of primary cultures of rat hepatocytes exposed to dialysed supernatants of rat, mouse and human macrophages or to recombinant human and murine interleukin 1 and tumour necrosis factor Recombinant cytokines in the range of 1 to 1000 ng/ml caused only reduction of albumin synthesis and slight stimulation of alpha 1 acid glycoprotein production while crude preparations of macrophage cytokines elicited typical acute phase response The results suggest that interleukin 1 or tumour necrosis factor are not likely the principal mediators responsible for the direct stimulation of normal rat hepatocytes to acute phase protein synthesis
60 citations
TL;DR: A stable distribution of pinnings did not develop during play fights in pairs of early weaned animals (Group 15S), and the rats with the higher pinning scores on the first day also had the higher frequency of pinning on the second and third day of the test.
45 citations
TL;DR: In several small limestone tunnels near Cracow it was found that on average Rhinolophus hipposideros awaken every 17.8 days, and Myotis myotis 41.2 days.
Abstract: In several small limestone tunnels near Cracow (50°02'N, 19°52'E) it was found that on average Rhinolophus hipposideros awaken every 17.8 days, and Myotis myotis 41.2 days.
42 citations
TL;DR: Dynamic quenching of ANS fluorescence by lipid-type spin labels is a useful new monitor of membrane fluidity that reports on various lipid mobilities in the membrane; a class of motion can be preferentially observed over others by selecting a proper spin label.
TL;DR: In this paper, the reactions of β-keto acid derivatives with trifluoromethylsulphenyl chloride were carried out to give the α-SCF 3 substituted esters, anilides, and their Schiff bases of acetyl- and benzoylacetic acids.
TL;DR: Data is reported for the quenching by acrylamide and succinimide of the fluorescence of a number of simple aromatic fluorophores in aqueous solution and these studies are consistent with an electron transfer quenched mechanism for the two quenchers.
Abstract: Abstract Here we report data for the quenching by acrylamide and succinimide of the fluorescence of a number of simple aromatic fluorophores in aqueous solution. Acrylamide is an efficient quencher of the fluorescence of most of these aromatic fluorophores, but succinimide is less efficient for all fluorophores and shows a very crude dependence on the ionization potential of the fluorophore. When the solvent is ethanol, the quenching efficiency by acrylamide and succinimide is found to decrease for the fluorophores, indole, naphthalene, and carbazole. These studies are consistent with an electron transfer quenching mechanism for the two quenchers. Quenching parameters (by acrylamide, succinimide, and iodide) are also reported for a number of fluorescent probes commonly used in biochemical studies. In general, the efficiency of acrylamide and succinimide quenching of these probes is low in aqueous solution.
TL;DR: In this article, the reaction of [Bzo 2 Me 4 [14]hexaenato(2−)N 4 ]Ni(II) with glutaryl chloride leads to new γ,γ′-disubstituted derivatives having γ and δ-unsaturated-δ-lactonic rings as substituents.
01 Jan 1987
TL;DR: Pulse radiolysis studies of anisyl-3,4-semiquinone, formed in the metabolic activation of 4-hydroxyanisole, a possible melanocytotoxic drug under current assessment as a treatment for malignant melanoma, have shown it to be unreactive towards oxygen, suggesting the cytotoxicity mechanism does not involve the generation of O2- and possible subsequent production of H2O2 and/or OH.
Abstract: Pulse radiolysis studies of anisyl-3,4-semiquinone, formed in the metabolic activation of 4-hydroxyanisole, a possible melanocytotoxic drug under current assessment as a treatment for malignant melanoma, have shown this semiquinone to be unreactive towards oxygen (k ≤ 105 M-1 s-1), although the reverse reaction of O2−− with anisyl-3,4-quinone is very rapid (k = 8.7 × 108M-1s-1). Since 1,4 benzoquinone is also unreactive towards anisyl-3,4-serniquinone (k ≤ 105M-1s-1), the one-electron reduction potential, E1/7 (anisyl-3,4-quinone/anisyl-3,4-semiquinone), is likely to be considerably more positive than 0.1V. This suggests that the cytotoxicity mechanism does not involve the generation of O2−− and possible subsequent production of H2O2 and/or OH·, leading to lipid peroxidation, as previously proposed, but rather involves as yet unknown reactions of anisyl-3,4-quinone. This quinone is unstable in water and its absorption spectrum was measured immediately (< 0.1s) following disproportionation of anisyl-3,4-se...
TL;DR: In Isohypsibius granulifer, yolk is autosynthesized and develops in the vesicles of the rough endoplasmic reticulum, associated with the outer membrane of the nuclear envelope, which forms blebs intensively during previtesllogenesis and early vitellogenesis.
Abstract: In Isohypsibius granulifer, yolk is autosynthesized. The Golgi apparatus is mainly responsible for the formation of yolk, which consists of irregular platelets with heterogeneous contents and a diameter of about 1 μm. Dense globules, 300 nm in diameter, are visible among yolk platelets. These develop in the vesicles of the rough endoplasmic reticulum. The genesis of these vesicles is associated with the outer membrane of the nuclear envelope, which forms blebs intensively during previtellogenesis and early vitellogenesis. The developing oocytes are assisted by nurse cells, to which they are jointed by cytoplasmic bridges. For every oocyte, there are a number nurse cells, which are sister cells of the oocyte. In addition to rRNA, nurse cells transfer to the oocyte lipids, platelets of yolk formed in their cytoplasm, mitochondria and cortical granules.
TL;DR: The ovulatory cycle of the domestic hen is approximately 26 h in length and the ovulates an egg each day at a progressively later time until she finally skips a day, resets her "clock" and a new sequence is started.
Abstract: The ovulatory cycle of the domestic hen is approximately 26 h in length. The hen ovulates an egg each day at a progressively later time until she finally skips a day, resets her "clock" and a new sequence is started. The ovarian component of this unique timing mechanism is the focus of this report. In Experiment 1, we asked whether there was a difference in luteinizing hormone (LH)-stimulated progesterone (P4) secretion by the granulosa layer removed from the largest follicle (F1) that had been the F1 follicle for 8, 12, or 32 h. In Experiment 2, our objective was to determine whether the theca layer of an F1 follicle influenced P4 secretion by the granulosa layer of that follicle and whether such an interaction depended on the maturity of the F1 follicle (had been a F1 follicle for 8 h or 32 h). Results from Experiment 1 revealed that there was no significant difference in LH-stimulated P4 secretion by the granulosa layer in a perifusion system regardless of the length of time the follicle had been the largest follicle. In contrast, in Experiment 2, when granulosa and theca layers from the same follicle were co-incubated in a perifusion system, P4 secretion from the more mature F1 follicle (32 h) increased in response to LH, whereas P4 secretion from the less mature F1 follicle (8 h) was not elevated by LH.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: The angioarchitecture of the superficial vascular hyaloid system (membrana vasculosa retinae) of the frog eye was studied by means of scanning electron microscopy of vascular corrosion casts as mentioned in this paper.
Abstract: The angioarchitecture of the superficial vascular hyaloid system (membrana vasculosa retinae) of the frog eye was studied by means of scanning electron microscopy of vascular corrosion casts. The terminal vessels form a single-layered sheath intimately adjacent to the vitreal side of the avascular retina. The hyaloid system is subdivided by the ventral venous trunk into three central areas: the dorsal, the temporo-ventral, and the naso-ventral area. Toward the ora serrata, the hyaloid system is bordered by an arterial ring, and by nasal and temporal venous branches forming more or less complete hemicircles. A vascular zone composed of several tongue-like sectors establishes an inter-connection between the peripheral vascular rings and the central areas of the fundus. The arterial blood is supplied from the arterial ring. The drainage of the hyaloid system is provided via two routes: (1) the Y-shaped ventral trunk collects blood from the central areas, (2) the two peripheral venous branches drain the tongue-like sectors. The vessels within the dorsal area follow preferentially a dorso-ventral meridional direction. This densely capillarized territory corresponds in localization to the area centralis retinae. The ultrastructure of microvessels of the hyaloid system is characterized by features typical for capillaries of the central nervous system.
TL;DR: The problem of chaotic behavior in multidimensional mixmaster models is discussed in this paper, where the authors classify n -dimensional homogeneous spaces possessing the structure of the product M 3 ×B, where M 3 is a threedimensional homogenous space.
TL;DR: Simultaneous and continuous irradiation with polarized green light, regardless of its plane of polarization, together with unpolarized far-red light, however, does lead to chloroplast reorientation, indicating that, in addition to the red-absorbing form of phytochrome, there exists in Mougeotia another sensory pigment absorbing green light.
Abstract: Continuous irradiation of Mougeotia with linearly polarized green light (550 nanometers, 0.2 watt per square meter) induces a change in the orientation of its chloroplast from profile to face position, if the electrical vector of the green light is vibrating normal to the cell axis. This change is complete within 25 minutes of the onset of irradiation. In contrast, if the electrical vector of the green light is parallel to the cell axis, no chloroplast reorientation is induced, even with a fluence rate as high as 3 watts per square meter. Furthermore, unpolarized far-red light (727 nanometers, 2 watts per square meter) given alone has no effect on chloroplast reorientation. Simultaneous and continuous irradiation with polarized green light, regardless of its plane of polarization, together with unpolarized far-red light, however, does lead to chloroplast reorientation. These data indicate that, in addition to the red-absorbing form of phytochrome, there exists in Mougeotia another sensory pigment absorbing green light.
TL;DR: In this paper, an expansive homeomorphism with the pseudo-orbit tracing property on a compact metric space is considered and stable and unstable "manifolds" with similar properties as in the hyperbolic case are observed near periodic points.
Abstract: Let f be an expansive homeomorphism with the pseudo orbits tracing property on a compact metric space. There are stable and unstable “manifolds” with similar properties as in the hyperbolic case, and similar behavior near periodic points is observed. Per ( f ) = Ω( f ) = CR(f) . Mappings Ω and CR are continuous at f .
TL;DR: The winged stages of Rhithrogena diaphana Navâs, 1917 are redescribed and drawn on the basis of fresh material collected not far from the type‐locality and the features distinguishing male adults and nymphs of these species from the other known species of the diaphanas‐group are keyed.
Abstract: The winged stages of Rhithrogena diaphana Navâs, 1917 are redescribed and drawn on the basis of fresh material collected not far from the type‐locality. The winged stages, the eggs and nymphs of three new species of the diaphana‐group are also described and illustrated: R. beskidensis sp.n., R. marcosi sp.n. and R. savoiensis sp.n. General remarks on the distribution and the biology are presented and the features distinguishing male adults and nymphs of these species from the other known species of the diaphana‐group are keyed.
01 Jan 1987
TL;DR: In this paper, the Raman spectra of MoO 3 -MeO/SiO 2 catalysts (Me = Co, Ni, Mn) revealed the presence of molybdate phases and the EPR spectra indicated changes in the oxidation state occurring on interaction with reaction mixtures containing various C 3 H 6 /O 2 ratios.
TL;DR: In this article, the authors show that the chaotic regime disappears in the full class of homogeneous arbitrarily dimensional cosmological models if the dimension of space is n ≠ 3, where n is the number of vertices in the model.
TL;DR: These fluorescence studies indicate that the binding of the substrates to phosphoglycerate kinase may influence the conformational dynamics around the two tryptophan residues located on one of the protein's domains.
Abstract: A frequency domain fluorescence study of yeast phosphoglycerate kinase has been performed to observe the effect of substrates on the structure and dynamics of the enzyme. At 20°C and pH 7.2, a biexponential decay is observed for tryptophanyl emission. The short fluorescence lifetime (0.4 ns) component is associated with a spectrum having a 329-nm maximum and a 18.4-kJ/mol activation energy, Ea, for thermal quenching. The long-lifetime (3.5 ns) component has a 338-nm maximum and an Ea of only 7.9 kJ/mol. Tentatively we assign the short and long-lifetime components to Trp-333 and Trp-308. Binding of the substrates ATP and 3-phosphoglycerate leads to a significant increase in the fluorescence lifetime, the red shift of the emission spectrum and in the decrease in the Ea for both components. Acrylamide-quenching studies indicate that the two tryptophan residues have about the same degree of kinetic exposure to the quencher and that the binding of the substrates causes a very slight change in the quenching pattern. These fluorescence studies indicate that the binding of the substrates to phosphoglycerate kinase may influence the conformational dynamics around the two tryptophan residues located on one of the protein's domains.
TL;DR: The pattern of the vascular supply to the choroid of the frog eye was studied in toto with the use of the injection-replication-SEM technique as mentioned in this paper.
Abstract: The pattern of the vascular supply to the choroid of the frog eye was studied in toto with the use of the injection-replication-SEM technique. The choroid of anuran amphibians is composed mainly of the choriocapillaris. In both species studied (Rana temporaria, Rana esculenta), an independent arterial supply to the choriocapillaris supplemented that from the ciliary arteries. This additional vascular route arises from the optic artery, a separate branch of the arteria infundibularis superficialis. The optic artery, accompanied by its vein within the vascular sheath of the optic nerve, joins the rich arterial capillary network of the choriocapillaris and supplies the posterior pole of the ocular bulb. The superficial capillary network displays a dense collar around the entrance of the optic nerve into the eye and is composed of a circular meshwork of small capillaries, several layers deep. More peripherally, however, it becomes single layered. This capillary network, as a whole, establishes numerous connections with the adjacent choriocapillaris at the posterior pole of the ocular bulb. In anuran amphibians the complex arrangement of both arterial systems supporting the choriocapillaris may be regarded as a more complete equivalent of the short posterior ciliary arteries of mammals.
TL;DR: The porphyrin accumulation pattern in this parasite can best be explained by postulating a deficiency of coproporphyr inogen oxidase activity, similar to that in human patients with hereditary coproporphyria.
TL;DR: In this article, the perturbed angular correlation was measured for 99Rh probe in dilute silver alloys with Cd, In, Sn and Sb impurities, and the attractive interaction between 99Rh and impurities was found and the binding energy of the probe-impurity pairs was determined.
Abstract: The perturbed angular correlation was measured for99Rh probe in dilute silver alloys with Cd, In, Sn and Sb impurities. The attractive interaction between99Rh and impurities was found and the binding energy of the probe-impurity pairs was determined.