Sacciform cells in the skin of teleost fish

The fine structure of sacciform gland cells of the epidermis is described in the number of species of teleost fish. In some of these the cell type had either not been found, or not recognized as such, before. Some histological and histochemical results are also reported. Despite considerable differences in the histochemistry and in the morphology of the sacciform cells over the range of species studied, some features of the fine structure are constant and can be used as diagnostic characters. The nucleus is peripheral, and there is a large membrane-limited lumen, into which the secretion is released from membrane-bounded vacuoles at the margin of the cytoplasm. It is probable that the secretion originates mainly in channels of endoplasmic reticulum which become swollen to form the vacuoles. Most sacciform cells open at the surface of the skin by an apical pore, but some have not been seen to open. The classification of the various unicellular glands of teleosts is discussed and it is concluded that attempts to categorise them by the nature of the secretion alone are unsatisfactory.     

Development of various nephron populations in birds during ontogenesis

Microanatomy of nephrons during ontogenesis has been studied in domestic hens. In the bird kidneys, as well as in mammalian kidneys, three populations of nephrons can be detected: juxtamedullary, or deep nephrons, superficial and situating between them intracortical nephrons. In formation of the bird renal medulla only loops of the juxtamedullary nephrons participate. During ontogenesis in the kidneys of birds, like in mammalians, juxtamedullary nephrons are the first to be formed; they can be obtained from kidneys of 14-day-old chicken embryos, however, a complete formation of the nephron structure is terminated after hatching. During development the length of the juxtamedullary nephrons increases nearly by one order, while the length of the superficial and intracortical nephrons increases no more than twice. The diameter of the glomeruli in the juxtamedullary nephrons during development increases nearly twice, in the superficial and intracortical nephrons only a slight increase is noted. A relative length of the proximal canaliculus of the intracortical and superficial nephrons gradually increases during ontogenesis and practically does not change in the juxtamedullary nephrons, in them the nephron loop becomes longer. The developmental pattern in various parts of the superficial, intracortical and juxtamedullary nephrons in general features is similar in mammalians and birds.     

Development of sex and protective behavior of female crickets Gryllus argentinus Sauss. at preproductive and reproductive periods of adult ontogenesis

The work presents data on reproductive and protective behavior of non-copulative female crickets Gryllus argentinus Sauss. at the beginning of adult ontogenesis. There is studied character of interaction of females with "virtual" males (the method of "trackball". The forms of female motor reactions are described and characterized in the model of male intraspecies signals--the call and aggressive ones. The character of development of female acoustic behavior is described by a change in the motor reaction forms in the course of adult ontogenesis. It is shown that at once after moulting the reproductive behavior on adults has not yet been formed, but is maturing gradually for several days. The passive protective behavior was established to be the most expressed at the initial stages of adult ontogenesis.     

被子植物胚珠研究进展

胚珠作为被子植物的有性生殖器官一直为植物学家所关注。19世纪以来, 人们从形态结构、发生发育、起源及分子生物学等方面对胚珠进行了大量的研究。近年来, 随着研究手段的不断改进, 研究者对许多关键性的问题, 如胚珠的起源、胚珠发生发育的分子机制已经有了一定的认识, 但是这些问题并未得到圆满的解决。对此, 本文对前人的研究内容进行了回顾,并综述了最新研究进展, 在此基础上提出了今后对胚珠研究的建议。     

Development of the ductule system of the epididymis in the prenatal period of human ontogeny

In 285 human embryos, prefetuses, fetuses and newborns by means of a complex of morphological methods, development of the epididymal canalicular system has been studied. The anlage of the epididymal canalicular system is stated to appear in embryos 13.0-17.0 mm long (the 6th week of development) and is presented as an accumulation of epithelial cells and primary germ cells between reducing glomeruli and mesonephric canaliculi. The canalization process of the cellular accumulations and their transformation into real canaliculi takes place during the first half of the prefetal period (the 8th week of development). Further growth and development of the epididymal canaliculi takes place in the craniocaudal direction and by the end of the prefetal period (the 12th week) the canaliculi of the head are already formed, they have a twisted course; within the limits of the body and tail they are yet poorly differentiated and their course is nearly straight. During the fetal period of ontogenesis, further differentiation of the epididymal parts occurs and structure of their canaliculi becomes more complex. They acquire a twisted course in all the parts of the organ; by the end of the fetal period the form and structure of the epididymal canaliculi resemble those of the definitive organ.     

Morphology of leaves of cyanus segetum LAM (Centaurea cyanus L.) after photoperiodic inhibition at different stages of ontogeny of the shoot apex

Cyanus segetum LAM. was transferred from a long to a short photoperiodic regime at various stages of ontogenesis and the development of the plant investigated. The morphology of the leaves ofCyanus segetum was dependent on the photoperiodic regime. On a short photoperiodic regime, pinnately sected leaves were formed, but only if development was inhibited while the shoot apex still had a structure characteristic for the vegetative plant. The ability to influence the shape of the leaves by a short day ends before the morphological differentiation of the inflorescence at the time of the disappearance of the vegetative structure and the formation of the meristematic mantle. After this time all leaves were smooth-edged like those of the controls on a long day. Although the ability to influence leaves was limited to the period of initiation of the leaf primordia, it was not restricted to the primordia then being initiated. The conditions of development also affected leaves whose primordia had already been initiated. This was evidently due to the action of photoperiodic conditions via ontogenesis. The position of the axils was also changed in dependence on the photoperiodic regime.     

Circadian molecular clocks tick along ontogenesis

The circadian system controls the timing of behavioral and physiological functions in most organisms studied. The review addresses the question of when and how the molecular clockwork underlying circadian oscillations within the central circadian clock in the suprachiasmatic nuclei of the hypothalamus (SCN) and the peripheral circadian clocks develops during ontogenesis. The current model of the molecular clockwork is summarized. The central SCN clock is viewed as a complex structure composed of a web of mutually synchronized individual oscillators. The importance of development of both the intracellular molecular clockwork as well as intercellular coupling for development of the formal properties of the circadian SCN clock is also highlighted. Recently, data has accumulated to demonstrate that synchronized molecular oscillations in the central and peripheral clocks develop gradually during ontogenesis and development extends into postnatal period. Synchronized molecular oscillations develop earlier in the SCN than in the peripheral clocks. A hypothesis is suggested that the immature clocks might be first driven by external entraining cues, and therefore, serve as "slave" oscillators. During ontogenesis, the clocks may gradually develop a complete set of molecular interlocked oscillations, i.e., the molecular clockwork, and become self-sustained clocks.     

The immune system and age

Basing on numerous facts, obtained during last years at investigation of the immune system organs, a definite idea has been formed on peculiarities of their structure during certain stages of human ontogenesis. The immune organs appear early in embryogenesis and by birth they have reached their morphological maturation. This is evident as formation of diffuse lymphoid tissue in lymphoid noduli, that can have germinative centers, where young cells of the lymphoid line are formed. The immune system organs develop especially quickly after birth during first years of the postnatal ontogenesis. The peak in development of the organs of immunogenesis, amount and size of the lymphoid noduli occurs during the childhood and adolescent age. Each immune organ has its peculiarities that are determined by their place in the organism, value and intensity of antigenic effect. Beginning from the adolescence and youth amount of the lymphoid tissue and lymphoid noduli in the organs decreases, in their place connective and adipose tissue grows out.     

Analysis of the embryonic development of Pogonophora in connection with the problems of phylogenetics

The development of the mesoderm in the Pogonophora being a point of argument, some stages of their ontogenesis are analyzed. The cleavage of Siboglinum caulleryi is considered as a modified spiral cleavage with the demonstration of the prospective significance of blastomeres. All mesoderm in Pogonophora is formed in enterocoelic mode from the anterior quadrant B. The spiral cleavage of pogonophores is compared to that of the Polychaeta and other animals. Some aspects of the formation and structure of the telosoma in the larva and adults are analyzed with a discussion of the nature of its segmentation. Some general problems of the evolution of the spiral cleavage are considered. The division of the Coelomata into 5 superphyla is confirmed, the Pogonophora being one of them.     

The autonomic division of oculomotor nerve nuclei in mammals and during human development]

Development of the vegetative component of the oculomotor nerve nuclei was studied in the main mammalia orders and in human ontogenesis. In phylogenesis parasympathetic nuclei of Jakubovitch--Edinger--Westphal and those of Perlia are formed later than somatic nuclei of the oculomotor nerve. The animals studied have, together with well developed somatic components of the oculomotor nerve nuclei, gomologues of parasympathetic nuclei, which are rather well developed in carnivores and monkeys. In human prenatal ontogenesis, somatic nuclei are formed first and then parasympathetic ones. Both parts of the oculomotor nerve nuclei are fully developed in adult man.     

Formation and reduction of provisional ventral foregut diverticulum in the embryos of Anguilliformes as the recapitulation of lungs

We described the development and subsequent reduction of ventral foregut diverticulum in the early ontogenesis of Anguilliformes in plankton samples collected in the coastal waters of central Vietnam. The diverticulum is a provisional structure derived from the ventral-lateral area of the caudal esophagus. It develops as a protrusion from the esophagus wall and consists of one cell layer. An increase in the volume of the diverticulum results from the proliferation of these cells and transformation of their shape. It was found that the development of the ventral diverticulum in eels is similar to the early stages of lungs formation in other vertebrates. The formation of ventral diverticulum of the esophagus was recorded in all studied embryos. The time and the extent of its development differs between species and can serve as an additional morphological character in the taxonomic identification of eels at early stages of their ontogeny.     

Development of the uterine microcirculatory bed in postnatal ontogeny

Age peculiarities of common structure of the microcirculatory pathways, specific volumes and amount of microvessels, zonal parameters of pericapillary microcirculation of metabolites, glycosamine glycans and glycoproteins contents, phosphatase and ATPase activity, collagen and elastic fibers of the microcirculatory bed vessels have been studied in 190 unchanged uteri, beginning from 36-week-old fetuses up to 35 years of age. The microcirculatory bed of myometrium during the period of postnatal ontogenesis investigated possesses a polymer-homonomous structural organization; its base make myoangiomas, including the terminal arteriole with precapillaries and collecting venule, that run from it. Similar structure of the myometrium microcirculatory pathways is already observed in fetuses of late antenatal period. In endometrium formed glanduloangionomas are revealed in the prepubertal age. Increase in glycosamine glycans contents is stated in the microvessel walls and in the uterine stroma during the process of its development. Compensatory-adaptive changes in the uterine microcirculatory bed are described during the newborn period up to the puberty. Functionally mature structures of the microcirculatory pathways in the submucosal and vascular layers of myometrium, endometrium and in the cervix uteri are found to be formed earlier than in other areas of the organ.     

Morphology of the inner ear of mammals in ontogeny

In both phylogenesis and ontogenesis, the inner ear is formed first as a core, which, phylogenetically, is the most ancient part of the peripheral region of the auditory system. Along with the development of the inner ear, other links of different evolutionary ages (the auricle is a phylogenetically young link) begin to form in the peripheral auditory system.     

Formation of heat-sensitivity in the ontogenesis of a heat-resistant Drosophila strain and the relation between this property and the mutation process

In the experiments with a heat-resistant line of Drosophila melanogaster, it has been shown that organismal heat-resistance is formed during ontogenesis, prior to hatching, though it can be changed, in accordance with the temperature conditions after hatching (acclimation). Heat-resistance of germ cells is formed during the pupal stage; it depends on the development temperature and remains unchanged thereafter. The mutation rate (the frequency of dominant lethals) in oocytes depends on the development temperature and not on the temperature life conditions of imago. Therefore, it may be concluded that heat-resistance of germ cells as well as their reaction on extreme temperatures are autonomous, meaning their independence of this property in the organism.     

被子植物胚珠研究进展

胚珠作为被子植物的有性生殖器官一直为植物学家所关注。19世纪以来,人们从形态结构、发生发育、起源及分子生物学等方面对胚珠进行了大量的研究。近年来,随着研究手段的不断改进,研究者对许多关键性的问题,如胚珠的起源、胚珠发生发育的分子机制已经有了一定的认识,但是这些问题并未得到圆满的解决。对此,本文对前人的研究内容进行了回顾,并综述了最新研究进展,在此基础上提出了今后对胚珠研究的建议。     

Structure and development of nephridia in Annelida and related taxa

Two different kinds of filtration nephridia, protonephridia and metanephridia, are described in Polychaeta. During ontogenesis protonephridia generally precede metanephridia. While the latter are segmentally arranged, protonephridia are characteristic for the larva and are the first nephridial structure formed during ontogenesis. There is strong evidence that both organs depend on the same information and that their specific structure depends on the way in which the coelom is formed and which final expansion it gains. While metanephridia are regarded to be homologous throughout the polychaetes, protonephridia seem to have evolved in several lineages. Some of the protonephridia closely resemble less differentiated stages of metanephridial development, so that protonephridial evolution can be explained by truncation of the metanephridial development. Nevertheless, structural details are large enough to allow us to expect information on the polychaete evolution if the database on polychaete nephridia increases. A comparison of the polychaete metanephridia with those of the Clitellata and Sipuncula reveals some surprising details. In Clitellata the structure of the funnel is quite uniform in microdrilid oligochaetous Clitellata and resembles that of the aeolosomatids. Like the nephridia in the polychaete taxa Sabellida and Terebellida, those of the Sipunucla possess podocytes covering the coelomic side of the duct.     

5-Hydroxytryptamine immunoreactivity in the epidermal sacciform gland cells of the clingfish Lepadogaster candollei Risso

Summary Serotonin has been demonstrated in the epidermal sacciform glandular cells of the clingfish Lepadogaster candollei by use of immunocytochemistry.Serotonin immunoreactivity is found both in the peripheral cytoplasm of the glandular cells and their luminal secretion. The presence of serotonin in the sacciform glandular cells parallels that located by both biochemical and immunocytochemical procedures in the cutaneous glands of many amphibian species.     

Development of the caudate nucleus of rats in postnatal ontogenesis and formation of cholinergic mediation in it]

Morphological maturation of the rat's caudate nucleus and formation of cholinergic system in it were studied in postnatal ontogenesis. Under investigation were newborn rats, 7, 14, 21 day old rats and adult animals. The growth and maturation of the caudate nucleys were most intesne during the first two postnatal weeks, it was somewhat descreased by the beginning of the third week and continued in later terms as well. The structure of dendrites and axons became complicated during the first two weeks, the axo-dendritic contacts being also formed. The neuron structure in 14 days old rats was similar to that of adult animals. The activity of acetylcholinesterase in the caudate nucleus of 7 and 14 days rats was not great. It sharply increased by the 17th day and reached the level of adults with 3 weeks after birth. Possible correlations of the morpho-chemical maturation of the caudate nucleus and formation of motor activity in rats is discussed.     

Neuronal Organization of Mammalian Stellate Ganglion in Postnatal Ontogenesis

The paper considers the problem of peculiarities of maturation of the stellate ganglion nerve elements in mammals of different species. This process differs in precocious and altricial animals. It has been shown that in spite of some individual peculiarities, the neurons, fibers, and conducting pathways in altricial animals are not, on the whole, completely formed morphologically and functionally. In the course of postnatal ontogenesis, not only an increase of cell sizes and development of dendrite tree, but also reorganization of nerve connections with target organ occur. The postnatal ontogenesis is also accompanied by an increase of the excitation transmission rate along the fibers and by their myelination. The asymmetry of the right and left stellate ganglia (SG) by their sizes and functional peculiarities, which exists in adult animals appears as soon as at early stages of postnatal development. The neural elements of precocious animals are changed to a lesser extent in postnatal ontogenesis and are, in many aspects, similar to those of adult organisms as early as at birth.     

Neuroblast differentiation and migration in the developing human spinal cord in the 1st half of prenatal ontogenesis]

The processes of neuroblasts differentiation and migration in the developing human spinal cord in the first half of antenatal ontogenesis were studied by the Golgi method. The neuron development was traced from the neuroepithelial matrix cells to the maturing neurons. A possible role of a special neuroblast outgrowth as a channel for its nucleus migration to the definite typological position of the mature neuron is suggested.