Ontogenetic Peculiarities Research Articles

Ontogenetic peculiarities of Scutellaria baicalensis Georgi under ex situ conditions

The paper refers to the study of the biological and ontogenetic peculiarities of the species Scutellaria baicalensis Georgi (Chinese skullcap) under ex situ conditions, specific to Republic of Moldova. Four life periods (latent, pregenerative, generative, postgenerative) and eight stages (plantlet, juvenile, immature, virginal, early generative, middle generative, late generative, senile) in the cycle of the development of plants were described. The ontogeny of S. baicalensis plants follows the type of monocentric biomorphs that partially disintegrate.

The specificity of cerebral lateralization in perception of emotional intonation of speech among children with special abilities

Much attention has been recently given to examination of developmental peculiarities of cognitive processes of children and adolescents with special abilities. The goal lies in comparative study of the ontogenetic peculiarities of cerebral mechanisms underlying the processing of emotional information in children who are engaged in extracurricular musical and mathematical activities. The sampling included the children engaged in additional activities and the control group, and consisted of the three age groups: 7-10 year, 10-13 years, and 14-17 years. In the conducted experimental studies, the respondents had to identify the emotional intonation of speech in the given phrase. The study revealed the significant ontogenetic differences in perception of emotional prosody of speech between the control group and the children engaged in additional activities. In the group of children of 7-13 years, who are engaged in additional classes, the predominant activity of left hemisphere testifies to the specificity of inter-hemispheric connections in the perception of emotional information. The dependence of the effects of cerebral lateralization on age was analogous in the groups of children engaged in mathematical and musical activities; and differed from the results of the control group, which allows claiming that the interinfluence of mathematical and musical skills is to a certain extent explained by the peculiarities of developmental age of cerebral lateralization in childhood and adolescence.

Morphology and ontogenesis of two new Hemiholosticha species (Ciliophora, Hypotrichia, Hemiholostichidae nov. fam.)

The morphology and ontogenesis of two new hypotrich ciliates, Hemiholosticha solitaria and Hemiholosticha germanica, were studied using live observation, protargol impregnation, and scanning electron microscopy. Both species share a medium-sized, almost globular body with a short anterior projection; two macronuclear nodules with a single micronucleus in between; a central contractile vacuole; three or four ventral, one postoral, one right and one left marginal cirral row; and three dorsal kineties extending along ribs. However, H. germanica is distinguished from congeners by a higher number of cirri in ventral rows R1 and R2 (3–6 vs. 2 cirri in each row). Hemiholosticha solitaria differs from congeners by having four (vs. three) ventral cirral rows and by the lack (vs. presence) of intracellular green algae. The ontogenesis of H. solitaria follows the H. pantanalensis mode in that (i) the oral primordium develops in a deep pouch and generates the first two cirral streaks in addition to adoral membranelles and undulating membranes, (ii) the undulating membrane anlage does not produce any cirri, and (iii) the longitudinal ventral cirral row R3 originates from two anlagen. The ontogenetic peculiarities along with the 18S rRNA gene phylogenies suggest classification of Hemiholosticha, Psilotrichides, and Urospinula into a new family, Hemiholostichidae.

Ontogenetic peculiarities of the effect of dantrolene and caffeine on the cardiac, respiratory and motor performance of intact and poisoned by physostigmine of rats

Activities of the somatomotor (MA), cardiovascular and respiratory systems were investigated in conditions of activation and blockade of ryanodine receptors (RyR) impaired cholinergic regulation in rat pups aged 3, 16 and 30 days. It was found that blockage of RyR by dantrolene has a negative chronotropic effect, the severity of which decreases with age, reduces the respiratory rate in rats on P3 and practically does not change in older animals. The amplitude of EMG and the power of motor bursts decreases in rats on P3-P16 and increases on P30. The duration of MA in the activity- rest cycle remains unchanged at P3 and decreases at P16-P30, which indicates a different change in the pattern of MA in rats of different ages after the blockade of RyR. Caffeine-induced activation of RyR is accompanied by an increase in heart rate and respiratory rate in rats on P30 and does not cause significant changes in these parameters on P3-P16. There has been an increase in all MA indices, especially in P3. Certain age-related regularities were revealed in the conditions of acetylcholinesterase inhibition by physostigmine, carried out against the background of RyR inhibition or activation. Maximum sensitivity to such effects was found in rats on P3. It was shown that in early postnatal ontogenesis of rats the sensitivity of RyR, including RyR2, to dantrolene is higher than in adult animals. Changes in RyR activity level do not prevent the development of pathological forms of heart rhythm that developing in rats after the physostigmine injection.

Ontogenetic peculiarities of autonomic regulation of the cardiovascular system of male rats by parameters of heart rate variability

Ontogenetic peculiarities of autonomic regulation of the cardiovascular system of male rats by parameters of heart rate variability

Features of Dictamnus albus (Rutaceae) in the pregenerative period of ontogeny in M. M. Gryshko National Botanical Garden in Ukraine

Investigation of plant ontogenetic peculiarities and establishment of boundaries of ontogenetic states of individuals is a necessary basis for studying their populations. The minimal amount of data on morphology of plants in the pregenerative period of ontogenesis complicates plant identification in natural and cultural populations. Such information is especially important for rare species of plants. Dictamnus albus L. is a perennial rare plant listed in the Red Book of Ukraine.The objective of this research is to analyze the peculiarities of ontomorphogenesis of D. albus, to establish diagnostic signs of age stages and the sequence of their passage for identification of the multivariance of development. The results of the study on D. albus ontomorphogeny in the latent and pregenerative period at the M. M. Gryshko National Botanical Garden оf the National Academy of Sciences of Ukraine are represented in this article. Diagnostic features of age stages: seeds, seedlings, juvenile, immature, virginile are established. The study shows a multivariate development that reveals different sequences of passing ontogenesis states by individuals and, accordingly, the rate of their aging and life expectancy. To describe the variation of the passage by individuals of ontogeny stages, we divided the stages into ontomorphs, which determined the degree of development-degradation of plants. The research showed that every age stage lasts for one growing season or longer. The first bloom in plants does not come earlier than the sixth year of vegetation. Seedlings and juvenile plants vary in leaf number and phyllotaxy. The development of immature plants takes place from the third year of vegetation. Seedlings, juvenile and young immature plants have a tap-root system. In individuals older than 4 years a root system forms which becomes similar to the fibrous root system due to the presence of several thickened roots. In immature and virginile plants, we observed the formation of adventitious roots on the caudex. It has been found that D. albus is characterized by heterophylly and morphological variability of leaves, which is developed during ontogeny and shoot formation. The variety of the architecture of individuals in the early stages of ontogenesis and the multi-variation of their development indicate the variation of the reaction rate.The data may be used for evaluate age (ontogenetic) structure of D. albus populations.

Catecholaminergic regulation of autorhythmical viscero- and somatomotor activity in early rat ontogenesis

Ontogenetic peculiarities of catecholaminergic regulation of three vitally important physiological processes are described: heart beating, respiration, and early somatomotor activity. They are subordinated to the autorhythmical regime and are submitted to modulating effects ofnoradrenergic and dopaminergic mechanisms. There are considered age-related changes of this effect whose peculiarity are polar changes of reactions in the process of their maturation from the predominantly excitatory at early stages to predominantly inhibitory ones.

Ontogeny of the Vertebral Column of Eleutherodactylus johnstonei (Anura: Eleutherodactylidae) Reveals Heterochronies Relative to Metamorphic Frogs

Over the last century, the morphogenesis of the vertebral column has been considered as a highly conserved process among anurans. This statement is based on the study of few metamorphic taxa, ignoring the role of developmental mechanisms underlying the evolution of specialized life-histories. Direct development in anurans has been regarded as evolutionarily derived and involves developmental recapitulation and repatterning at different levels in all amphibian taxa studied so far. Herein, we analyze the vertebral column morphogenesis of the direct-developing frog Eleutherodactylus johnstonei, describing the sequence of chondrification and ossification, based on cleared and double-stained specimens from early stage embryos to adults. In general, our results show that the morphogenesis of the vertebral column in E. johnstonei recapitulates the ancestral tadpole-like pattern of development. However, the analysis of the sequence of events using heterochrony plots shows important heterocronies relative to metamorphic species, such as a delay in the chondrification of the vertebral centra and in osteogenesis. These ontogenetic peculiarities may represent derived traits in direct-developing frogs and are possibly correlated with its unusual life history. In addition, several features of the vertebral column of E. johnstonei are highly variable from its typical morphology. We report some malformations and small deviations, which do not seem to affect the survival of individuals. These anomalies have also been found in other frogs, and include many vertebral defects, such as vertebral fusion, and vertebral preclusion and/or induction.

Ontogenetic peculiarities of regulation of apoptosis of hypothalamic neurosecretory cells in TNF-knockout mice

Tumor necrosis factor (TNF) participates in regulation of many processes including carcinogenesis and apoptosis. However, at present, there are practically absent the works on peculiarities of regulation of apoptosis in tnf-knockout (tnf-/-) mice. These mice develop without morphological abnormalities, but they seem to have disturbances of many biological processes, such as inflammation, programmed cell death, etc. Therefore, the goal of our work was to study possible pathways of regulation of apoptosis in the absence of TNF in neurosecretory cells (NSC) of young and old mice. For this purpose, we determined immunohistochemically expression of apoptosis markers caspase-8, -9. Bax, Bcl2, Mcl1, neuropeptide vasopressin, and the apoptosis level in hypothalamus in tnf-knockout mice of different ages as compared with mice with unchanged level of TNF synthesis. It was shown that the apoptosis activation observed during aging did not depend on the tnf gene, and apoptosis at aging was caspase-dependent. It has been revealed that at aging in mouse NSC the external cell death pathway with participation of caspase-8 is activated. The pathways mediating cell death in different neurosecretory centers at aging are different. Thus, in supraoptic nucleus (SON), in all studied animal groups, animal groups, an important cause of the NSC apoptosis is Bax. In paraventricular nucleus (PVN), of the greater importance is a decrease of the antiapoptotic protection. Hence, misbalance of synthesis of proteins of the Bcl-2 family plays an important role in development of senescent apoptosis.

Ontogenetic peculiarities of the effect of endothelin-1 on tissue homeostasis of various cell populations in albino rats.

The effects of endothelin-1 on tissue homeostasis in newborn and adult albino rats were studied by(3)H-thymidine autoradiography, staining with AgNO(3), computer-assisted morphometry, and biochemiluminescence. In adult rats the ability of endothelin-1 to activate DNA synthesis in epithelial cells decreased compared to that in newborn animals; inversion of the stimulatory effects of endothelin-1 on the nucleolar apparatus of cardiomyocytes and pronounced intensification of free radical oxidation in the heart were also seen in adult animals. These differences can be related to ontogenetic peculiarities of endothelin-1 reception.

Phylogeny, ontogeny and adaptive radiation in the superfamily Tydeoidea (Acari: Actinedida), with a reappraisal of morphological characters

The Tydeoidea as a whole (Tydeidae, Iolinidae and Ereynetidae) are analysed cladistically for the first time, based on a critical reappraisal of morphological characters. In addition to the chaetotaxy, solenidiotaxy and poroidotaxy, the following characters ale considered: form of dehiscence line; number of eyes; presence of a posterior trichobothrium; number of discs on genital acetabula; breadth of cis-acetabulal area; sexual dimorphism (indicative of true mating segmentation of legs and palps; presence and structure of ereynetal organ; shape of chelicerae and tarsus II and number of calyptostases. Special attention is paid to a comparative study of the segmentation and chaetotaxy of the palp within the superfamily. as well as to the presence of prodorsal eye-spots, variations of the posterior sensilla and the segmentation of femur IV during ontogeny. Three types of phylogenetic analyses are employed: phenetic, cladistic and ontogenetic. The phenetic approach reveals that the current classification relies heavily on overall similarity between taxa, especially in adults, supplemented by ontogenetic peculiarities, such as the calyptostatic nymphs of Speleognathinae. The cladistic analyses lead to a reorganization of the Tydeoidea into four families. The Meyerellidae, characterized by the presence of three prodorsal eye-spots, include the Meyerellinae and Triophytydeinae. while the Tydeidae are restricted to Australotydeinae, Pretydeinae and Tydeinae. The remaining two families, Iolinidae and Ereynetidae, form the informal group Procurvata, characterized by the procurved dehiscence line. The family Iolinidae is enlarged to encompass the subfamilies Tydaeolinae, Pronematinae and Iolininae. The Ereynetidae, characterized by the ereynetal organ and double genital discs, include the Ereynrtinae :senior synonym of Pseudotydeinae, transferred from the Tydeidae), Lawrencarinae and Speleognathinae. Minor discrepancies were found between the results for immatures and adults. These can be explained by ontogenetic trajectories that are not parallel and undergo a spectacular expansion into the character space as they extend. Within the Tydeoidea, diversification and adaptation have occurred through acceleration, with adult adaptations extending into earlier stases. Heterostasy is only expressed in the Speleognathinae, in which the nymphs are all calyptostatic. The monophyly of the Tydeoidea remains questionable, since the Meyerellidae might constitute a separate group, more closely related to the Eupodoidea. The Meyerellidae aside, the tydeoid mites seem to have originated from a group of free-living forms that colonized the soil and related habitats and underwent an early radiation, giving rise to three major lineages: the Tydeidae, Iolinidae and Ereynetidae. The Tydeidae are characterized by a low evolutionary rate combined with a high diversification indicative of a secondary adaptive radiation within the Tydeoidea. In contrast, the Iolinidae are characterized by a high evolutionary rate combined to a low diversification. The third lineage, the Ereynetidae, is highly diverse, showing high rates of evolution and speciation, linked to the adoption of endoparasitic habits. Different hypotheses to explain the success and diversification in Tydeidae and Ereynetidae are examined. (C) 2000 The Linnean Society of London.

Phylogeny, ontogeny and adaptive radiation in the superfamily Tydeoidea (Acari: Actinedida), with a reappraisal of morphological characters

The Tydeoidea as a whole (Tydeidae, Iolinidae and Ereynetidae) are analysed cladistically for the first time, based on a critical reappraisal of morphological characters. In addition to the chaetotaxy, solenidiotaxy and poroidotaxy, the following characters are considered: form of dehiscence line; number of eyes; presence of a posterior trichobothrium; number of discs on genital acetabula; breadth of cis-acetabulal area; sexual dimorphism (indicative of true mating); segmentation of legs and palps; presence and structure of ereynetal organ; shape of chelicerae and tarsus I; and number of calyptostases. Special attention is paid to a comparative study of the segmentation and chaetotaxy of the palp within the superfamily, as well as to the presence of prodorsal eye-spots, variations of the posterior sensilla and the segmentation of femur IV during ontogeny. Three types of phylogenetic analyses are employed: phenetic, cladistic and ontogenetic. The phenetic approach reveals that the current classification relies heavily on overall similarity between taxa, especially in adults, supplemented by ontogenetic peculiarities, such as the calyptostatic nymphs of Speleognathinae. The cladistic analyses lead to a reorganization of the Tydeoidea into four families. The Meyerellidae, characterized by the presence of three prodorsal eye-spots, include the Meyerellinae and Triophtydeinae, while the Tydeidae are restricted to Australotydeinae, Pretydeinae and Tydeinae. The remaining two families, Iolinidae and Ereynetidae, form the informal group Procurvata, characterized by the procurved dehiscence line. The family Iolinidae is enlarged to encompass the subfamilies Tydaeolinae, Pronematinae and Iolininae. The Ereynetidae, characterized by the ereynetal organ and double genital discs, include the Ereynetinae (senior synonym of Pseudotydeinae, transferred from the Tydeidae), Lawrencarinae and Speleognathinae. Minor discrepancies were found between the results for immatures and adults. These can be explained by ontogenetic trajectories that are not parallel and undergo a spectacular expansion into the character space as they extend. Within the Tydeoidea, diversification and adaptation have occurred through acceleration, with adult adaptations extending into earlier stases. Heterostasy is only expressed in the Speleognathinae, in which the nymphs are all calyptostatic. The monophyly of the Tydeoidea remains questionable, since the Meyerellidae might constitute a separate group, more closely related to the Eupodoidea. The Meyerellidae aside, the tydeoid mites seem to have originated from a group of free-living forms that colonized the soil and related habitats and underwent an early radiation, giving rise to three major lineages: the Tydeidae, Iolinidae and Ereynetidae. The Tydeidae are characterized by a low evolutionary rate combined with a high diversification indicative of a secondary adaptive radiation within the Tydeoidea. In contrast, the Iolinidae are characterized by a high evolutionary rate combined to a low diversification. The third lineage, the Ereynetidae, is highly diverse, showing high rates of evolution and speciation, linked to the adoption of endoparasitic habits. Different hypotheses to explain the success and diversification in Tydeidae and Ereynetidae are examined.

Morphogenesis and ultrastructure of the soil ciliate Engelmanniella mobilis (Ciliophora, Hypotrichida)

The morphogenetic pattern, freeze-fracture, transmission, and scanning electron-microscopy of interphasic cells were used to elucidate the enigmatic systematic position of Engelmanniella mobilis. Frontal, buccal, parabuccal, and marginal cirri are distinguishable during cortical development; transverse, frontoterminal (migratory), and caudal cirri are absent. Ontogenetic peculiarities include the conservation of parental and grandparental marginal cirri and the apokinetal origin of a dorsal kinety in the opisthe. Thus, interphasic cells of E. mobilis possess three generations of cirri. The pellicle is multilamellated. Prominent, undischargeable subpellicular granules consisting of a homogeneous osmiophilic mass develop from bundles of long fibers. Rhomboid crystal-like structures projecting from the lithosomes and regularly patterned mitoribosomes are additional remarkable ultrastructural characteristics. The somatic and frontal cirri comprise 2-10 kinetosomes. Very likely, all cirri are composed of closely adjacent "dikinetids" because their kinetosomes form pairs each possessing a transverse and a postciliary microtubular ribbon. The fourth row of kinetosomes of the adorai membranelies shows the usual transverse microtubular ribbons, while one or two transverse microtubules are closely adjacent to the third and the second row of its basal bodies. Our data suggest that Engelmanniella has descended from a kahliellid lineage. However, its placement in a well-founded (!) stichotrichid family is impossible at present.

Vers une Classification Phylogénétique des Espèces du Genre Riccia

Presently only about half of the species of the genus Riccia are well known, but the available data can be used to propose a phylogenetic classification. The following are discussed: The origin of Riccias by the late Paleozoic Era or the Triassic Period of the Mesozoic Era, the possible life conditions from the arid Mesozoic to the present, the interpretation as primitive of those general characteristics common to all species, the interpretation of unique features as adaptive or evolu- tionarily advanced and the phylogenetic interpretation of spore morphology and micromorphology. Spores retained in tetrads are considered archaic to dissociated spores. Spore surface ornamentation is indicative of the degree of evolution. Chemical, cytological and ontogenetic peculiarities are insufficiently known to aid in phylogenetic determinations. Certain taxa are more significant than others as evolutionary indicators: R. caroliniana, an archaic species, a kind of living fossil; R. membranacea with small, verrucose, spherical spores; R. perssonii with echinulate, undivided spores and Riccia sect. Pilifer, a recent taxon as shown by geographic distribution. A scheme is provided in an attempt to indicate the hypothetical phylogenetic relationships among species groups.