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L K Obukhova

Publications and source records attributed to L K Obukhova.

At least 19 recordsLinked to original sources
PubMed2004

Correlations of life-span variation parameters in 128 successive generations of Drosophila melanogaster with changes in atmospheric pressure and geomagnetic activity.

Correlations between the parameters of life-span (LS) distribution of Drosophila melanogaster, including mean LS (MLS) and the time of 10 and 90% population mortality, and some geophysical parameters that are usually beyond the control of researchers dealing with laboratory cultures, including atmospheric pressure, solar activity indices (Wolf's sunspot numbers and 2,800-MHz radio flux), and geomagnetic activity (planetary index, K(p)), were studied. Geophysical data were obtained from free-access official web sites of the National Oceanic & Atmospheric Administration of the US Department of Commerce and the Institute of Terrestrial Magnetism and Radiowave Propagation of the Russian Academy of Sciences. The geophysical parameters were calculated only for the period corresponding to 10 days of preimaginal development of the flies from egg to imago. Canonical correlation analysis, calculation of the non-parametric Spearman rank-order correlation coefficients, and graphical data analysis were used. Highly significant correlations between parameters of LS distribution in males and females and environmental factors, such as the atmospheric pressure on the 4th and 5th day of development and geomagnetic activity indices (K(p)) on the 6th and 10th day of development were found, with correlation coefficients varying from 0.31 to 0.37 (P<0.02). Assuming a causal relationship between geophysical factors and LS, it may be hypothesized that energetically weak environmental factors determine the formation of LS oscillatory dynamics in laboratory populations. The possible mechanisms underlying the contribution of these environmental factors to the LS variation in successive generations are discussed.

Animals↗
PubMed2004

[Analysis of the life span distribution mode in 128 successive generations of D. melanogaster].

A large body of experimental data consisting of 116 samples (sets) of individual life span (LS) values of D. melanogaster from the same laboratory strain Canton-S was analyzed. In total, 10180 Drosophila flies (5100 females and 5080 males) were studied. Each of 58 pairs of samples belonged to a definite generation in a continuous succession where every next generation was an offspring of the preceding one. Mathematical simulation made it possible to demonstrate that both the normal (Gaussian) and Gompertz distributions were equally good approximations of the experimental data. Both of them adequately described the LS distributions in laboratory populations of D. melanogaster. The confidence intervals for absolute deviations of the theoretical distributions from experimental ones were small (4-5%). In other words, the approximation error was no more than 5% in either case. The estimation of the dependence of approximation quality on the LS in the original (experimental) population showed that the normal distribution was preferable, because, in this case the absolute deviation from the experimental distribution was independent of the LS in the original population.

Age Distribution↗
PubMed2003

Life span variations in 128 successive generations of D. melanogaster. I. Evidence that the phenomenon exists and analysis of the variations mode.

Survival of Drosophila melanogaster was estimated in 128 successive generations for 5 years. The resultant 116 samples (58 for females and 58 for males) containing series of individual values of life span (LS; 50-90 values in each series) were analyzed. Each of 58 pairs of samples belonged to a definite generation in a continuous succession where every next generation was an offspring of the preceding one. In total, 10180 Drosophila flies (5100 females and 5080 males) were studied. The mean life span (MLS) was found to be considerably heterogeneous in the series of generations: in many pairs of consecutive generations, MLSs significantly differed within two errors of the mean (P<0.05), and the minimum and maximum MLSs in the series differed from each other almost twofold. The use of the nonparametric Kruskal-Wallis test made it possible to conclusively demonstrate highly significant (P<0.001) differences between LS distributions and their medians in the series of successive generations of D. melanogaster. Highly significant (P<0.0001) positive correlations (from 0.61 to 0.91) between the parameters characterizing the minimum (t(10)), mean, and maximum (t(90)) LSs were found. This indicates considerable consistency of the LS variations in successive generations of the same population, with the proportions of individuals with low and high LSs remaining about the same irrespective of the MLS. It was demonstrated with the use of mathematical simulation that the MLS changes in successive generations may be regarded as an oscillatory process and described as a sum of several (three to five) harmonic components. The calculated determination coefficients were high (93.51 and 88.93% for females and males, respectively). This indicates that the mathematical model used for simulation adequately described the observed variations in MLS. The results are discussed in terms of population gerontology and the problem of geroprotector effectiveness.

Aging↗
PubMed2003

[Analysis of nonlinear dynamics of aging (experimental study)].

The research is devoted to the analysis of individual dependencies of weight of a body, rectal temperature and functional motor asymmetry of behavior of mice female CBA from age received in longitudinal research. Both individual, and the average age dependencies of the above named parameters have an extreme (nonlinear) kind. It is revealed, that by the age of achievement of the maximal weight (Tm) and greatest asymmetry of behavior (Tn) are connected with each other (r = 0.6, p < 0.001). The difference (Tm-Tn) is linearly connected to life expectancy (r = 0.62, p < 0.001), that is this parameter can be used for the forecast of individual life expectancy.

Aging↗
PubMed2001

[The aging of the brain: relationship of difference between left and right cerebral hemisphere potential and motor asymmetry of mice].

Difference between left and right cerebral hemisphere potential (mV) is biophysical reflection of brain asymmetry. Cymbate changes of constant potential run during the life in both hemisphere of brain of mice. Number turning on the right of 10 attempt in T maze is a quantitative criteria of functional motor asymmetry. Manifest right asymmetry of behavior of mice observe only from 12 to 17 month old. Ambylateral behavior is character to animals younger and older this period. Thus, as difference between left and right cerebral hemisphere potential both motor asymmetry have nonlinear change with age. Coefficient of correlation between this parameters equal -0.42 for young (3-7 month) mice, +0.53 for old (21-28 month) mice. But this coefficient is near zero for mice from 11 to 19 month old. Results of our research show, that quality change in brain run in middle age.

Age Factors↗
PubMed2000

Effect of epitalon on the lifespan increase in Drosophila melanogaster.

The geroprotector activity of epitalon, a synthetic tetrapeptide Ala-Glu-Asp-Gly, was studied on the Drosophila melanogaster wild strain Canton-S. The substance was added to the culture medium only at the developmental stage (from egg to larva). Epitalon significantly increased the lifespan (LS) of imagoes by 11-16% when applied at unprecedented low concentrations-from 0.001 x 10(-6) to 5 x 10(-6) wt.% of culture medium for males and from 0.01 x 10(-6) to 0.1 x 10(-6) wt.% of culture medium for females. The increase in LS did not depend on the substance dose. Effective concentrations of epitalon were 16,000-80,000,000 times lower than those of melatonin. The possible mechanisms of the antioxidant and regulatory effects of epitalon are discussed.

Animals↗
PubMed1999

Geroprotector effectiveness of melatonin: investigation of lifespan of Drosophila melanogaster.

The lifespan (LS) of Drosophila melanogaster was studied under the effect of melatonin at a concentration of 0.08% selected in preliminary experiments. The compound was introduced into a culture medium only at the stage of development. An inverse relationship was observed between the change in LS after the impact of the preparation and the value of LS in the corresponding control group (Spearman's rank correlation coefficient R = -0.83, P < 0.02). For a relatively low LS in a population from which the control and experimental groups were formed, the geroprotector effect of melatonin is the most distinct; for a relatively high LS, the effect of the hormone is either not detected or appears as a toxic reduction in LS (up to 10%) in the experimental group. Such nonuniform effects of melatonin are connected with fluctuating changes in viability in successive generations of D. melanogaster. The antioxidant mechanism of the geroprotector effect is also discussed.

Aging↗
PubMed1996

Geroprotector efficiency depends on viability of control population: life span investigation in D. melanogaster.

Ability of the radical spin trap 4-hydroxy-2,2,6,6,-tetramethyl-l-piperidine-N-oxyl (4-hydroxy-TemPO, (4HT)), to delay senescence in D. melanogaster has been studied. The spin trap, at a concentration of 0.2%, was added to the culture medium at the flies development stage. Reliable correlation (r = 0.76, P < 0.05) has been found between the viability of a control population, assessed by the mean life span (LS) value, and the level of LS alteration after geroprotector treatment in a corresponding experimental population. Thereby the local minimum values and local decreases in the mean LS in successive generations of the control line are associated most likely with LS extension effects in the corresponding experimental groups after 4HT treatment, and on the contrary, the local maximum values and local increases in the mean LS of the control line are associated more probably either with LS decreasing effects in the corresponding experimental groups or with the lack of significant differences between the control and experimental groups. A possible mechanism of the discovered phenomenon is discussed, based on the concept about free-radical activity variations. A probability approach to the evaluation of geroprotector efficiency in serial studies is proposed.

Aging↗