Age-related peculiarities of antioxidant system functioning in the blood of ostriches

The intensity of lipid peroxidation, activity of some enzymes antioxidant system - superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, amount of recovered glutathione and ceruloplasmin in the blood serum of ostriches in a period from 6- to 60-month age were first investigated. The increase of concentration of lipid peroxidation products is accompanied by the decline of amount of general lipids in the ostriches blood. Every life cycle period of ostriches is characterized by the indexes of functioning of the antioxidant system and intensity of accumulation intermediate lipid peroxidation products inherent in it. The pubescence period and intensive oviposition are characterized by the increase of products lipid peroxidation concentration and decrease of antioxidant enzymes activity, which can testify to the exhaustion of protective possibilities of enzymatic link of antioxidant defence.     

Age-related peculiarities of acetylation of rat liver nuclear histones]

The intensity of acetylation of different histone fraction is found to change in postnatal ontogenesis of albino rats. The intensity of acetylation of lisine-rich histone (F1) was maximal in 3-and 12-month old animals. The label incorporation into F3 (arginine-rich) histones considerably decreased in the time interval between 1st and 3d months while its incorporation increased into F2 histones furing all the period of postnatal development studied.     

Age-related peculiarities of dynamic structure of wave of the human arterial blood pressure

A decrease of elasticity of walls of aorta and large arteries in the process of human natural aging leads to a significant increment of pulse arterial pressure (AP) due to a reflected wave and accordingly to a rise of the load on myocardium and arterial walls. Therefore, an enhancement of the arterial wall stiffness is considered as a possible mechanism and at the same time as a prognostic factor of risk of development of diseases of the cardiovascular system (CVS). For detection and quantitative estimation of this factor, we applied method of arterial piezopulsometry that allows revealing characteristic age-related peculiarities of the dynamic structure of AP pulse waves, which were used at development of the way and algorithm of express-diagnostics of the functional state of the human CVS. The perspective use of this method for detection of signs of the age-related CVS readjustment as a factor of the organism aging is discussed.     

Age-related changes in the functioning of the mitochondrial potassium-transporting system

Changes in the rate of respiration and functioning of the ATP-dependent potassium channel in liver and heart mitochondria of one-, three-, eight-, and 24-month-old Wistar male rats have been investigated. It was shown that the activity of the channel in the mitochondria of both tissues in 24-month-old animals decreases more than three times, and the content of potassium, 1.5–2 times compared with young one-month-old rats. The changes occur against the background of age-related decrease of energy supply in mitochondria, the respiratory complex-I undergoing the greatest changes upon aging. The decrease of channel activity may be the result of changes in channel sensitivity to modulators and a decrease in the expression of mitochondrial K+-transporting channel-protein with a molecular mass of 5.5 kDa upon aging found in this work. As a result, the functioning of not only the mitoK_ATP but also the whole mitochondrial potassium cycle is impaired.     

Age-related peculiarities of glutathione content changes in the brain of rats during immobilization stress

The work is aimed at studying age-related peculiarities as regards glutathione content changes in the brain of rats under immobilization stress. It has been established that some changes in the content of reduced glutathione take place in the brain in the process of ontogenesis. During immobilization stress the content of this metabolite decreases in the brain of all age groups of rats under study. To a greater extent this shift manifests itself in 2- and 24-month-old rats which are characterized by more active stress-stimulated free-radical processes in the brain and by an initially higher level of reduced glutathione.     

Age-related peculiarities of change in content of free radical oxidation products in muscle during stress

The age-dependent peculiarities of stimulation of free radical processes in subcellular fractions of skeletal muscle of rats subjected to long-term immobilization stress were studied in order to improve knowledge about changes of muscular tissue during ontogenesis. It is found that adult animals do not show accumulation of proteins carbonyls, TBA-reactive substances, and Schiff bases in subcellular fractions of the thigh muscle when immobUized. Long-term immobilization causes apparent manifestation of oxidative stress only in mitochondrial fraction in pubertal rats. Mitochondrial oxidative stress defense systems are sufficiently effective, however, direction of pathways of free radical oxidation carbonyl products catabolism alters in the cytoplasm of myocytes in old rats under long-term immobilization conditions.     

Secondary rhythms of automatically functioning systems

In wakeful rats at the age from newborn to 3 weeks there were studied interrelations of rhythmical oscillations of heart rate, respiration rate, and periodic spontaneous motor activity. In all studied systems, these oscillations are coordinated and occur in several frequency diapasons. Frequencies in the near-minute diapason (the period from 30 to 90 s) are the most constant and do not change with age. Regular oscillations are the most stable in newborns. Bursts of motor activity usually are irregular, but episodically the distinct near-minute rhythm is traced. Studies of the character of interaction of the heart activity, respiration, and periodic somatomotor excitation allow stating that the main coordination pathway of spontaneous autorhythmic functions in early postnatal ontogenesis is formation of secondary rhythms. Possible ways of formation of the secondary rhythms are considered.     

Characteristics and peculiarities of cortical evoked potentials following stimulation of visceral afferent systems

A detailed characterization is given of the evoked potential of the cat cortex following stimulation of various visceral nerves. It is shown that the visceral analyzer has two kinds of projections: strictly local and diffuse. Its stimulation evokes in the cortex two types of potentials — primary and secondary. Primary responses (PR) of the projection zone show where the signal is addressed, indicating only that the focus of excitation arose at the periphery. Therefore, various attempts to increase the information value of PR are not prospective. The information value of secondary responses (SR) are apparently important for understanding cortical processes developing in it after the occurrence of PR. These reactions are diverse and appear at the same point of the cortex following stimulation of different modalities; at the same time their distribution is limited to four cortical areas: association, limbic, motor, and orbital. The convergence of sensory inputs observed in secondary regions probably reflects elementary integration accomplished in them.The material was reported at the All-Union symposium "Electrical Responses of the Cortex to Afferent Stimulation," Kiev. October, 1969.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 2, No. 2, pp. 113–125, March–April, 1970.     

Some peculiarities of functioning of H+-ATPase from the membranes of the anaerobic bacterium Lactobacillus casei

Radiation inactivation analysis gave the target sizes of 176 +/- 5 kDa and 275 +/- 33 kDa for ATPase from anaerobic Lactobacillus casei and aerobic Micrococcus luteus bacteria respectively. The values are close to the known molecular masses of the enzymes. Thus, to function the L. casei ATPase, like the F1-ATPases, requires a complete structure composed of all the enzyme subunits. L. casei ATPase is inhibited by 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole owing to modification of an amino acid residue(s) with pK greater than 8.5. L. casei ATPase consists of six identical subunits and differs from alpha 3 beta 3 gamma delta epsilon-type F1-ATPases in a number of catalytic properties. Namely, ATP hydrolysis under the 'unisite' conditions proceeds at a relatively high rate suggesting the absence of cooperative interactions between the catalytic sites. Contrary to mitochondrial F1-ATPase. L. casei ATPase does not form an inactive complex with ADP. These findings imply essential differences in the operating mechanism for L. casei ATPase and F1 ATPase.     

Age-related changes in the daily rhythm of photoreceptor functioning and circuitry in a melatonin-proficient mouse strain

Retinal melatonin is involved in the modulation of many important retinal functions. Our previous studies have shown that the viability of photoreceptors and ganglion cells is reduced during aging in mice that lack melatonin receptor type 1. This demonstrates that melatonin signaling is important for the survival of retinal neurons. In the present study, we investigate the effects of aging on photoreceptor physiology and retinal organization in CH3-f+/+ mice, a melatonin proficient mouse strain. Our data indicate that the amplitude of the a and b waves of the scotopic and photopic electroretinogram decreases with age. Moreover, the daily rhythm in the amplitude of the a- and b-waves is lost during the aging process. Similarly, the scotopic threshold response is significantly affected by aging, but only when it is measured during the night. Interestingly, the changes observed in the ERGs are not paralleled by relevant changes in retinal morphological features, and administration of exogenous melatonin does not affect the ERGs in C3H-f(+/+) at 12 months of age. This suggests that the responsiveness of the photoreceptors to exogenous melatonin is reduced during aging.     

Species loss and the structure and functioning of multitrophic aquatic systems

Experiments and theory in single trophic level systems dominate biodiversity and ecosystem functioning research and recent debates. All natural ecosystems contain communities with multiple trophic levels, however, and this can have important effects on ecosystem structure and functioning. Furthermore, many experiments compare assembled communities, rather than examining loss of species directly. We identify three questions around which to organise an investigation of how species loss affects the structure and functioning of multitrophic systems. 1) What is the distribution of species richness among trophic levels; 2) from which trophic levels are species most often lost; and 3) does loss of species from different trophic levels influence ecosystem functioning differently? Our analyses show that: 1) Relatively few high‐quality data are available concerning the distribution of species richness among trophic levels. A new data‐set provides evidence of a decrease in species richness as trophic height increases. 2) Multiple lines of evidence indicate that species are lost from higher trophic levels more frequently than lower trophic levels. 3) A theoretical model suggests that both the structure of food webs (occurrence of omnivory and the distribution of species richness among trophic levels) and the trophic level from which species are lost determines the impact of species loss on ecosystem functioning, which can even vary in the sign of the effect. These results indicate that, at least for aquatic systems, models of single trophic level ecosystems are insufficient for understanding the functional consequences of extinctions. Knowledge is required of food web structure, which species are likely to be lost, and also whether cascading extinctions will occur.     

Age-related dynamics of the parameters of somatosensory evoked potentials in healthy children

The purpose of this study was to evaluate the parameters of somatosensory evoked potentials (SSEPs) in healthy children of different age groups (n = 94). The amplitudes of the main cortical peaks and the central sensory conduction time (CSCT) from n. medianus and n. tibialis in children aged under 12 months, 1–12 years, and 12–17 years were estimated and compared. No significant cortical peaks were recorded from the tibial nerve in five children younger than 1 year (5 out of 23, 22%). Significant differences in CSCT were observed between the children younger than 1 year and two other groups. The amplitudes did not significantly differ between the groups. Thus, SSEPs may be used for the evaluation of somatosensory pathways in children aged one month to 17 years. CSCT differs significantly between children younger than 1 year and other age groups. Age-related reduction in CSCT and elevation of the cortical peak amplitudes may reflect the myelination of somatosensory pathways and the improvement in nervous system integration.     

Age-related changes in serum/plasma biochemical parameters of WHHLMI rabbits.

We developed myocardial infarction-prone rabbits (WHHLMI rabbits) by selectively breeding coronary atherosclerosis-prone WHHL rabbits. To examine the serum/plasma biochemical parameters of this animal model, we assayed the lipid and glucose levels, and enzyme activities of WHHLMI rabbits from 2 to 26 months of age using solid phase analysis. The results showed a good correlation with those measured with a conventional method. The serum enzyme activities and lipid levels varied with aging despite almost no change in the plasma glucose levels. Gender differences were observed in the total cholesterol, triglyceride, and lactate dehydrogenase activity levels. The data on these serum/plasma biochemical parameters will be useful in studies of myocardial infarction or pharmacological studies using this model.     

Population-related peculiarities of molecular stress-responsive systems of bivalve mollusk under the effect of tetrazine pesticide

Tetrazine pesticides are widely used for the treatment of crops in most EU countries and USA. However, data about the effect of environmentally realistic concentrations of biocides on the molecular stress response system in non-target organisms are absent. The aim of our study was the comparison of adaptive capability of bivalve mollusk Anodonta cygnea from two populations under the effects of commercial pesticide Apollo in terms of biochemical parameters of the digestive gland. The differences between parameters of oxidative stress and glutathione transferase activity in specimens of control groups from clean (I group) and polluted (B group) areas have been shown. Under the effect of Apollo, the level of protein carbonyls and microsomal oxidation processes increased, and the level of metallothioneins and oxyradical formation decreased in the specimens from both populations. However, the treatment provoked the activation of antioxidant processes in the I group and their inhibition in B group. Potentially the injury of cellular thiols, glutathione and metallothioneins, seems to be key point of tetrazine pesticides toxicity.     

Effects of semen fractionation and dilution ratio on equine spermatozoal motility parameters

Two experiments were conducted to examine the effects of semen fractionation and dilution ratio on motility parameters of stallion spermatozoa. In Experiment 1, three ejaculates from each of three stallions were divided into sperm-rich (SR) and sperm-poor (SP) fractions to determine the difference in sperm concentration. Mean sperm concentration in SR fractions (349.5 x 10(6)/ml) was greater (P < 0.001) than that of SP fractions (96.9 x 10(6)/ml). In Experiment 2, three ejaculates from each of two stallions were divided into SR and SP fractions. Fifty percent of the original volume of SR fractions was combined with 50% of the original volume of SP fractions for each ejaculate to represent total ejaculates. SR and total ejaculates were diluted with skim milk-glucose semen extender as follows: 1) no dilution, or dilution to 2) 100 x 10(6)sperm/ml, 3) 50 x 10(6)sperm/ml, or 4) 25 x 10(6)sperm/ml. Semen samples were evaluated at 0.5, 3, 6, 12, and 24 h postejaculation (25 degrees C storage temperature) for percentages of total spermatozoal motility (TSM) and progressive spermatozoal motility (PSM). Mean TSM was greater (P < 0.05) in SR ejaculates than total ejaculates at 12 and 24 h postejaculation. Mean TSM of undiluted semen was lower (P < 0.05) than other dilution ratios over all periods. Mean TSM was greater (P < 0.05) at a 25 x 10(6)sperm/ml dilution ratio than a 50 x 10(6)sperm/ml dilution ratio at 12 and 24 h postejaculation, and greater (P < 0.05) than a 100 x 10(6)sperm/ml dilution ratio from 3 to 24 h postejaculation. Similar patterns were found for PSM. Collection of SR ejaculates and dilution to 25 x 10(6)sperm/ml improved longevity of spermatozoal motility.     

Biodiversity effects on ecosystem functioning: insights from aquatic systems

Unprecedented rates of species extinctions have prompted extensive research into the consequences of biodiversity losses on ecosystem functioning. While aquatic species are most threatened, research with freshwater and marine model systems has lagged behind progress made in terrestrial environments. This editorial to a special feature summarizes the main outcomes of a conference aimed at setting the stage for exploring the potential of aquatic systems to assess the role of biodiversity in ecosystem functioning. This series of papers proposes fresh approaches to the study of biodiversity effects on ecosystem functioning, outlines a new way of analyzing experimental data, presents a model that considers scale as an important factor determining outcomes, explores the effects of multiple stressors on species richness and ecosystem processes, and develops a food-web perspective that relates ecosystem properties to biodiversity. An insightful synthesis of lessons learned from aquatic systems is premature at present, but the papers clearly demonstrate the role that marine and freshwater systems can play in resolving open questions. The implications go well beyond the biodiversity in, and functioning of, ecosystems shaped by free-flowing or standing water.