[Some problems of the evolutionary adaptatiogenesis].

Evolution of organisms is adaptive process as a whole, but its adaptiveness is fully revealed in long periods of phylogenesis. To form the complex adaptations, the phyletic evolution is more favourable than relatively short-term processes of speciation. Selection can influence on a given character of organism only after achievement of some minimal selectable degree of its development, that is specific for each adaptation. For some complex adaptations, the minimal selectable value of the character can be essentially higher than the initial degree of its expression. In such cases the corresponding adaptations evolve either on the basis of the morpho-functional preadaptations or using some relatively large hereditary changes ("saltations") as the elementary evolutionary material for selection. The negative consequences of such saltations can be mitigated by the compensatory ontogenetic modifications. Elucidation of the minimal selectable value of characters seems to be useful also to evaluate probability of the hypotheses explaining adaptive causes of corresponding evolutionary transformations. The notions of the ecto- and endosomatic organs (after A.N. Severtzov, 1939) are relative ones. The primary evolutionary changes (protallaxes) can arise in any organism system and cause the arising of secondary alterations (deutallaxes, or internal adaptations) in other system.

[Phenogenetic variability and population meronomy].

In accordance with M.A. Shishkin's epigenetic evolutionary theory and S.V. Meyen's concept of meron, N.P. Krenke's "phenogenetic variability" can be considered as a realization of developmentally determined laws of possible transformations of particular characters (morphogenetic realization of meron). It includes two components: deterministic (organizing) one and stochastic (random) one. Organizing includes (epigenetic variability) represents a canalized component of morphogenesis determined by creode structure and arrangement of epigenetic thresholds, which alows to speak about morphogenetic rule of meronomic transformations. Random (realized) variability corresponds with stochastic component of morphogenesis, which makes it possible a spontaneous shifting of available developmental programs and selection of alternative subcreodes. Concepts of "population epigenetic landscape", "population ontogenesis" and "population meronomy" are introduced. Population ontogenesis (PO) can be considered as a peculiar deformation of species developmental program common to all individuals in particular population. This deformation is historically adjusted to concrete environmental conditions by natural selection. PO reflects general set of potential developmental patterns in concrete population, and it should be peculiar and unique one in respect to the whole species. It may be assumed that each individual contains information about invariant population epigenetic landscape (PEL), and thereby discrete individual phenotypes represent a probabilistic copy of general population epigenetic pattern. Analysis of bilateral structures among members of the same generation permits to visualize the principal pattern of PEL. Epigenetic thresholds and constructional bans constrain probable morphogenetic transformations and creates PEL, which is a general rule-cliché that formats total disparity of character states and theirs stochastic manifestation in taxonomic units, populations and individuals. Based on Waddington's ideas of creode, S.V. Meyen introduced concepts of intracreode and extracreode. Population meronomy allows to characterize peculiarities of extracreode of a population or a taxonomic unit while studying intracreodes as intraindividual variability by means of phenetical analysis (reductional stage) and phenogenetic synthesis (compositional stage). In this case we estimate not individual variability (plasticity) proper but generalized population or taxonomic epigenetic diversity of intracreode, which in actually becomes an extracreode. Population-meronomic analysis of bilateral compositions of antimere structure elements allows to construct a natural system of structure transformations and thereby to visualize meronomic diversity and transformation paths of meron.

The effect of size-dependent growth and environmental factors on animal size variability.

The origin of variation in animal growth rate and body size is not well understood but central to ecological and evolutionary processes. We develop a relationship that predicts the change in relative body size variation within a cohort will be approximately equal to the relative change in mean per unit size growth rate, when only size-dependent factors affect growth. When modeling cohort growth, relative size variation decreased, remained unchanged, or increased, as a function of growth rate-size scaling relationships, in a predictable manner. We use the approximation to predict how environmental factors (e.g., resource level) affect body size variation, and verified these predictions numerically for a flexible growth model using a wide range of parameter values. We also explore and discuss the assumptions underlying the approximation. We find that factors that similarly affect mean growth rate may differently affect size variation, and competition may increase body size variation without changing size-independent relationships. We discuss implications of our results to the choice of growth equations used in models where body size variation is an important variable or output.

Unexpected discontinuities in life-history evolution under size-dependent mortality.

In many organisms survival depends on body size. We investigate the implications of size-selective mortality on life-history evolution by introducing and analysing a new and particularly flexible life-history model with the following key features: the lengths of growth and reproductive periods in successive reproductive cycles can vary evolutionarily, the model does not constrain evolution to patterns of either determinate or indeterminate growth, and lifetime number and sizes of broods are the outcomes of evolutionarily optimal life-history decisions. We find that small changes in environmental conditions can lead to abrupt transitions in optimal life histories when size-dependent mortality is sufficiently strong. Such discontinuous switching results from antagonistic selection pressures and occurs between strategies of early maturation with short reproductive periods and late maturation with long reproductive cycles. When mortality is size-selective and the size-independent component is not too high, selection favours prolonged juvenile growth, thereby allowing individuals to reach a mortality refuge at large body size before the onset of reproduction. When either component of mortality is then increased, the mortality refuge first becomes unattractive and eventually closes up altogether, resulting in short juvenile growth and frequent reproduction. Our results suggest a new mechanism for the evolution of life-history dimorphisms.

Developmental constraints in a comparative framework: a test case using variations in phalanx number during amniote evolution.

Constraints are factors that limit evolutionary change. A subset of constraints is developmental, and acts during embryonic development. There is some uncertainty about how to define developmental constraints, and how to formulate them as testable hypotheses. Furthermore, concepts such as constraint-breaking, universal constraints, and forbidden morphologies present some conceptual difficulties. One of our aims is to clarify these issues. After briefly reviewing current classifications of constraint, we define developmental constraints as those affecting morphogenetic processes in ontogeny. They may be generative or selective, although a clear distinction cannot always be drawn. We support the idea that statements about constraints are in fact statements about the relative frequency of particular transformations (where 'transformation' indicates a change from the ancestral condition). An important consequence of this is that the same transformation may be constrained in one developmental or phylogenetic context, but evolutionarily plastic in another. In this paper, we analyse developmental constraints within a phylogenetic framework, building on similar work by previous authors. Our approach is based on the following assumptions from the literature: (1) constraints are identified when there is a discrepancy between the observed frequency of a transformation, and its expected frequency; (2) the 'expected' distribution is derived by examining the phylogenetic distribution of the transformation and its associated selection pressures. Thus, by looking for congruence between these various phylogenetic distribution patterns, we can test hypotheses about constraint. We critically examine this approach using a test case: variation in phalanx-number in the amniote limb.

Insulin/IGF and target of rapamycin signaling: a TOR de force in growth control.

'They come in all sizes.' Apart from its origin and use in the clothing industry, this saying reflects the fact that the size of organisms spans an enormous range. Whether destined to be large or small, species grow in an organized fashion to reach their final specified size. For growth to proceed, food must be metabolized to liberate energy in the form of adenosine triphosphate (ATP) and protein building blocks in the form of amino acids. One major orchestrator of this complex growth process in diverse metazoan species is the insulin/insulin-like growth factor (IGF) system. This review summarizes current studies primarily from Drosophila regarding the function of the insulin/IGF system in the control of growth.

Anandamide activity and degradation are regulated by early postnatal aging and follicle-stimulating hormone in mouse Sertoli cells.

Anandamide (AEA), a prominent member of the endogenous ligands of cannabinoid receptors (endocannabinoids), is known to adversely affect female fertility. However, a potential role of AEA in male reproductive functions is unknown. Here we report evidence that immature mouse Sertoli cells have the biochemical tools to bind and inactivate AEA, i.e. a functional type-2 cannabinoid receptor (CB2R), a selective AEA membrane transporter, and an AEA-degrading enzyme fatty acid amide hydrolase. We show that, unlike CB2R, the activity of AEA membrane transporter and the activity and expression of FAAH decrease, whereas the apoptosis-inducing activity of AEA increases with age during the neonatal period. We also show that FSH reduces the apoptotic potential of AEA, but not that of its nonhydrolyzable analog methanandamide. Concomitantly, FSH enhances FAAH activity in a manner dependent on mRNA transcription and protein synthesis and apparently involving cAMP. These data demonstrate that Sertoli cells partake in the peripheral endocannabinoid system, and that FSH reduces the apoptotic potential of AEA by activating FAAH. Taken together, it can be suggested that the endocannabinoid network plays a role in the hormonal regulation of male fertility.

[Advance in studies on compensatory growth of aquatic animals after starvation or undernutrition].

This paper reviewed the studies on the compensatory growth of aquatic animals after starvation or undernourisment. The extent of compensatory growth, its affecting factors, physiological mechanisms, changes in chemical composition and dynamics of growth rate were discussed. The experimental design problems and the application prospects of related studied were also analyzed.

The molecular evolution of development.

Morphological differences between species, from simple single-character differences to large-scale variation in body plans, can be traced to changes in the timing and location of developmental events. This has led to a growing interest in understanding the genetic basis behind the evolution of developmental systems. Molecular evolutionary genetics provides one of several approaches to dissecting the evolution of developmental systems, by allowing us to reconstruct the history of developmental genetic pathways, infer the origin and diversification of developmental gene functions, and assess the relative contributions of various evolutionary forces in shaping regulatory gene evolution.

[Life cycle strategies: a synthesis of empirical and theoretical approaches]. / Strategii zhiznennogo tsikla: sintez émpiricheskogo i teoreticheskogo podkhodov.

A scheme of relationships among life-history characters is developed on assumptions of determinate growth and dependence of juvenile mortality on the specific growth rate. It is shown that constraints on the relative neonate size, (W0/W infinity), and minimum value of the biotic potential, (rmax), lead to "triangular" shape of life history set on the plain defined by juvenile and adult mortality. This completely coincides with the Ramenskii++--Grime (C-S-R) classification of life-history strategies. Phylogenetic constraints can reduce this set to a relatively narrow r/K-continuum specifically oriented for a certain taxon. Similar restrictions generate models of life history optimization which predict interspecific allometries between life-history traits.

Cardiovascular measurements in animals in the milligram range.

The study of microscopic animals should be intensified because: most of the world's animal biomass consists of very small animals; life as a small animal is both qualitatively and quantitatively very different from that of a large animal; and almost all animals are very small as they begin their development. Fortunately, developing technology now allows us to make quantitative measurements in microscopic animals. This paper describes new techniques for measuring cardiovascular variables such as blood pressure, stroke volume, heart rate and cardiac output in animals weighing as little as a few mg. Non-invasive techniques such as videomicroscopy can be used for determining heart stroke volume in small animals. Impedance measurement is another non-invasive or minor invasive technique for determining rates of heart beat, gill or lung ventilation and limb movement as well as giving qualitative information on changes in blood flow. Pulsed Doppler technology can be used to obtain blood flow velocity in small vessels. Invasive techniques depend on servo-null micropressure systems that record pressure through glass microelectrodes that are implanted into the vessel or heart lumen. This allows stable pressure recordings for up to 5-6 h in animals weighing as little as a few mg. Microinjectors can be used for intravascular injections of vasoactive drugs (or blood withdrawals). Newly emerging techniques for in vivo cardiovascular measurements allow us to understand the function of the cardiovascular system in a larger portion of the world's animal biomass, as well as in the immature and as yet poorly understood early developmental stages of animals.

As time goes by: children's early understanding of growth in animals.

Beliefs about naturally occurring transformations were examined in children aged 3 to 6 years in 4 experiments. Experiment 1 tested children's understanding that animals (but not artifacts) predictably get larger over time. Experiment 1a examined whether the results obtained in the first experiment could be attributed to an added memory component on the artifact task. Experiment 2 further examined beliefs about the aging of artifacts. In Experiment 3, color and shape (metamorphosis) changes of animals were investigated. At all ages, children appeared to understand that animals get larger and not smaller with age. While older children and adults allowed for rather dramatic changes in the size and shape of animals over the life span if the alternative involved decreasing in size with age, preschool children were less willing to accept these changes. Taken together, the results of these studies suggest that even young preschool children have 2 conceptual insights about natural transformations: that they are lawful and nonrandom, and that they are domain and mechanism specific. Further, children as young as age 3 are able to go beyond the perceptual appearance of animals in making judgments about transformations caused by growth. Implications for children's understanding of personal and species identity are discussed.

[Temporal patterns of animal development]. / Izuchenie vremennýkh zakonomernostei razvitiia zhivotnykh.

A summary of studies on temporal characteristics of animal development performed during last 30 years using dimensionless unit as a parameter of development duration is presented. This approach allowed to introduce time as a parameter in comparative embryological studies. Thus the time of development became a subject of the embryological studies. Perspectives for the future work are defined.

Castration method and progesterone-estradiol implant effects on growth rate of suckling calves.

Eighty male calves nursing their dams and averaging 15 d of age were used to evaluate a method of nonsurgical castration and a growth implant in a 196-d experiment. On the 1st d of the experiment, 40 calves were castrated chemically using Chem-Cast (active ingredient: lactic acid 88% wt/wt), and 40 were castrated surgically. Twenty calves on each castration treatment were implanted with STEER-oid on d 1 and reimplanted on d 121 while 20 calves on each treatment were not implanted on either date. Chemical castration resulted in significantly lower scrotal edema and a trend toward increased rate of gain at d 28. Castration treatment did not affect 196-d rate of gain and weaning weights of calves. On d 121, bilateral castration was determined in 30 of 40 chemically castrated calves, a condition that persisted on d 196, resulting in a 75% castration rate. Implanted calves had rates of gain that were 14, 6, and 4% higher, respectively, on d 28, 121, and 196 compared with unimplanted calves.

Ontogenesis of intestinal transport of 5-methyltetrahydrofolate in the rat.

Developmental aspects of the intestinal transport of 5-methyltetrahydrofolate (5-CH3H4-PteGlu) were studied in suckling (14-day-old), weanling (22-day-old), and adult (90-day-old) rats by use of the intestinal everted-sac technique. Mucosal-to-serosal transport of 0.5 microM 5-CH3H4PteGlu was linear with time for 40-min incubation and occurred at a rate of 0.035, 0.032, and 0.010 nmol X g initial tissue wet wt-1 X min-1 for suckling, weanling, and adult rats, respectively. The transport of 5-CH3H4PteGlu in all age groups was pH dependent (maximal at pH 6) and was higher in the jejunum than in the ileum. In all age groups the transport of 5-CH3H4PteGlu occurred by an active carrier-mediated system. The system was saturable; energy, temperature, and Na dependent; inhibited by structural analogues; and capable of accumulating the substrate against a concentration gradient. Kinetic parameters of the transport process, however, showed some difference. A progressive decrease in Vmax was observed from suckling to weanling to adult rats (5.1, 3.7, and 0.8 nmol X g initial tissue wet wt-1 X 30 min-1, respectively), while apparent Kt was similar (2.2, 1.73, and 1.79 microM, respectively). This study demonstrates that the transport system of 5-CH3H4PteGlu in the rat is fully developed at the suckling age. The results also suggest that the activity and/or the number, but not the affinity, of the transport carriers decrease with maturation.

Correlation between mammary prolactin receptors of lactating mice and litter weight.

Correlations between numbers and dissociation constants of mammary prolactin receptors of lactating mice and litter weight were examined. The apparent numbers and dissociation constants of mammary prolactin receptors were obtained from Scatchard plots with inhibition of iodine-125 prolactin binding by various concentrations of unlabeled prolactin. Litter weight measured 5 h after separation from the mother showed a nearly quadruple, almost linear increase during the first 15 d after birth. The dissociation constant for prolactin binding was fairly constant through lactation and did not correlate with either number of prolactin receptors or litter weight. The number of prolactin receptors in mammary cells increased rapidly in early lactation, reached a maximum at mid-lactation, began to decrease thereafter, and was correlated closely with litter weights on d 5 (.70) and 10 (.64) postpartum, suggesting that number of prolactin receptors represents the lactational potential of the lactating mouse.