Postnatal development of the rabbit pineal gland. A light- and electron-microscopic study.

The development of the rabbit pineal gland has been studied by light and electron microscopy from the 1st to the 120th postnatal day. After 24 h of postnatal life, the pineal parenchyma is highly cellular, showing two identifiable cell types: pinealocytes I and II. Immature type II pinealocytes arrange either in cellular cords or clusters or forme rosette-like structures. At the 5th postnatal day, corticomedullar differentiation is established. Rosette-like structures and cellular cords are absent from the cortex. Along the postnatal period, nuclei of pinealocytes are set apart due to cytoplasmic widening and development of cell processes. These structures pervade the cellular cords and rosette-like structures formed by immature type II pinealocytes. Rosette-like structures are no longer seen beyond the 30th postnatal day, and cords of type II pinealocytes from the 90th postnatal day on. At this time, the rabbit pineal gland is considered to be histologically mature.     

Cytological characteristics of the gonocytes in the course of their migration in early rat embryos]

The work was carried out in 23 rat embryos from 9,5 to the 11th day of development. In 9,5-day embryos the primary sex cells are localized in the mesenchyma of the allantois and in the intestinal entoderm. Later they migrate either with the blood flow or on the surface of cellular layers towards gonad germs which are reached by the 11th day of the intrauterine development. In the course of this process there occur structural and cytochemical changes in gonocyte nuclei. The nucleolus is replaced to the periphery of the nucleus, around it there appears a rim intensively stained with methylene green. Chromatin has a shape of thin threads. These changes of the nuclei seem to be associated with an increased synthesis of r-DNA and hence with the synthesis of substances having the role to prevent the somatic differentiation of primary sex cells in the course of migration.     

Effect of protein-energy deficiency on the composition of the glial population of the mouse neocortex

A quantitative analysis of the cellular elements composition of the neocortex has been performed in 40-day-old mice, that have been given full-bodied synthetic diet (10% of protein) and the diet with the half concentration of the nutritive substances (5% of protein) beginning from the 10th day of their life. The protein-energetic insufficiency during the postnatal period produces retardation in the formation and differentiation processes of oligodendrogliocytes, as well as results in decrease of gliocytesatellites in the neocortex.     

Purification and characterization of perchloric acid soluble protein from rat lung

We isolated a perchloric acid soluble protein from the post-mitochondria supernatant fraction of the rat lung and designated it as RLu-PSP1. The protein is soluble in 5% perchloric acid and was purified by ammonium sulfate fractionation and CM-Sephadex chromatography. The amino acid sequence of RLu-PSP was identical with that of rat liver PSP (RL-PSP). RLu-PSP inhibited protein synthesis in a rabbit reticulocyte lysate system. It was expressed mainly in cytoplasm of bronchioles and alveolar epithelial cells of the lung from 60-day-old rats. In 15-day-old rat embryos, the epithelial-lining of the terminal buds of the respiratory tree was immunopositive. The expression of RLu-PSP increased from the embryonic 15th day to the postnatal 40th day. This is the first report on the presence of a PSP in rat lung and on its involvement in the regulation of cellular growth and differentiation.     

Ultrastructural characteristics of the differentiation of glandular cells in the anterior pituitary gland of collared lemmings (Dicrostonyx) from the Vrangel Island

In 15.5-, 16-, 17.5-, 18.5-, 20-day-old fetuses and newborn lemmings, the ultrastructure of the anterior lobe of the hypophysis has been studied. In the parenchyma of the 15.5-day-old fetus gland, some cells containing secretory material are revealed, but they are difficult for identification, since differentiation of their organellas is not completed and polymorphism of their granules is strongly manifested. On the 17.5th day of the prenatal development TTH-, ACTH-, LH-, STH-secreting adenocytes are detected; they include secretory granules having diameters 70--100 nm, 80--150 nm, 60--140 nm and 200--400 nm, respectively. On the 18.5th day FSH-secreting cells are identified. Lactotropocytes appear on the 20th day. The anterior lobe of the hypophysis of 17.5--18.5-day-old fetuses are characterized by a high level of the secretory activity which decreases to some extent before birth. Ultrastructure of the cellular organellas in the newborn hypophysis is similar to that in a mature animal, nevertheless, the diameter of the secretory granules does not reach the size of these elements in mature individuals.     

Effects of maternal administration of diethylstilbestrol and estradiol on the newborn guinea pig

The subcutaneous injection of diethylstilbestrol (2.5 micrograms/day) into pregnant guinea pigs from the 28th or 40th day to term resulted in an accelerated tempo of differentiation of the genital tract of the female offspring at birth, as well as intense estrogenic stimulation. Estradiol (50 micrograms per day) injected over the same period caused insignificant estrogenic stimulation in the newborn. The normal embryogenesis of the genital tract is described and a pattern of caudocranial differentiation identified. The normal genital tract is described as a basis for the analysis of results in the newborn. Comparative studies in other animals are discussed.     

Development of the gigantocerebellum of the weakly electric fish Pollimyrus

The morphogenesis of the "hypertrophied" mormyrid cerebellum was investigated in Pollimyrus (Pisces). Two adults and 36 larvae and young fish raised in captivity were used. Two Gnathonemus petersii adults were taken for comparison. The ontogenetic development of the various cerebellar structures was analysed in inverse chronological order with the aid of serial sagittal and frontal brain sections. Special attention was given to the trilobed corpus cerebelli (C1, C2, C3), the lobi transitorii et caudales, the valvula, the crista cerebelli, the eminentia granularis and the lobus lineae lateralis. 1. The cerebellar structures are of bilateral origin; they develop from the cerebellar and acoustico-lateral "anlage" of the rhombencephalon behind the rhombomesencephalic fissure, either through budding or individualisation and appear between the 4th and 11th day after spawning. The midline fusion of the symmetrical structures is accomplished somewhat later, between the 8th and 23rd days. 2. The cerebellar structures acquire their definitive spatial organisation within 38 days, except for the valvula whose development takes much longer. Recognisable from the 11th day, the valvula upon which ridges are visible from the beginning continues to grow after the 38th day beyond the mesencephalic ventricle, finally overlying the telencephalon frontally and the different rhombencephalic structures caudally. This development, which includes a large antero-lateral folding of the valvula, takes 240 days. 3. Cytological differentiation is just as complex as the general development of the cerebellar structures. Cortical stratification first begins on the 8th to the 11th day in the corpus cerebelli and in the valvula from day 21 to 23 onwards. This differentiation is characterised throughout almost the entire cerebellum by a downward migration of the superficial undifferentiated cells which then constitute the granular layer. In the valvula, the majority of the undifferentiated cells leave the ridges to form a continuous granular layer at the base of the ridges. 4. A differentiation gradient was observed on the antero-posterior axis. 5. In spite of its complexity, the mormyrid cerebellum develops much more rapidly than the cerebellum of the trout.     

Tissue-specific antigen of chick adenohypophysis appearing at early stages of histotypic differentiation]

The tissue-specific water-soluble antigen characterized by alpha1-globulin electrophoretic mobility was revealed in chick adenohypophysis. The antigen was shown to appear in embryogenesis at early stages of histotypical differentiation of the adenohypophysis by indirect immunofluorescence. The first cells with specific fluorescence were found simultaneously in the cephalic and caudal lobes of 6-day embryo adenohypophysis. The bright patterned fluorescence was observed in all cellular cords of the adenohypophysis by the 8--10th day of the development. This antigen may be used as a common marker for pituitary cell differentiation.     

激动素在黄瓜子叶器官分化中的作用

采用在培养初期分阶段供应激动素 (KT)的方法 ,研究了其对黄瓜子叶器官分化的影响 ,并对全程供应和不供应KT下子叶中内源多胺和内源激素的变化进行了动态测定。结果表明 :1)供应KT使不定根分化率下降 ,不影响营养芽的分化 ,而对于花芽分化则是必需的。2 )供应KT使多胺中腐胺 (Put)含量变化最为显著 ,在培养第 2、 6d出现峰值 ,在第 4d呈低谷 ,对照则在第 4d出现峰值。 3)供应KT使培养 2d的子叶中吲哚乙酸 (IAA)和脱落酸(ABA)含量显著降低 ,4d时IAA含量显著升高。据上结果 ,就这些生理变化和花芽分化之间是否存在相关进行了充分讨论。     

Study of serotonin effects on histogenesis of embryonic rat neocortex on a model of ectopic neurotransplantation

A comparative study of dynamics of development of ectopic grafts of the embryonic (E14) neocortical anlagen obtained from intact rats, rats injected with serotonin inhibitor para-chlorophe-nylalanine (PCPA) on the 11th day of pregnancy as well as the same anlagen incubated before grafting in the serotonin-containing medium. The aim of the study was to reveal influence of serotonin on division and differentiation of the embryonic neocortical cells. Investigation of degeneration, mitotic activity and differentiation (using immunohistochemical revealing of the nuclear protein of nervous cells (NeuN)) of the grafted cells demonstrated contribution of serotonin to survival and differentiation of neuroepithelial cells of the grafts and also to regulation of their proliferation. Serotonin is supposed to have a stimulatory effect on the rate of cellular cycle of the grafted cells, thereby accelerating differentiation of neurons.     

维生素C通过调控脂肪形成相关基因的转录促进猪前体脂肪细胞的增殖与分化

探讨维生素C（Vit C）诱导猪前体脂肪细胞增殖分化最佳浓度及在分化过程中,5种脂肪形成相关基因peroxisome proliferator activated receptor gamma(PPARγ)和retinoid X receptor alpha(RXRα),脂肪细胞分化标志基因lipoprotein lipase (LPL),生脂基因phosphoenolpyruvate carboxykinase(PEPCK)、stearoyl CoA desaturase(SCD) mRNA表达时序性的变化. 以3　d龄猪前体脂肪细胞为实验对象,用Vit C诱导猪前体脂肪细胞增殖分化,分别在增殖分化第2、4、6和8 d收获细胞,利用MTT测定其增殖程度;油红O染色提取法检测其脂肪含量;采用SQ RT PCR法检测脂肪生成相关基因PPARγ、RXRα、LPL、PEPCK和SCD mRNA表达的变化. 结果显示,PPARγ mRNA在诱导分化第2 d时有低水平表达,在诱导分化过程中表达量逐步升高,在终末分化阶段仍保持高水平表达;RXRα mRNA在诱导分化第2和4 d表达量很低,诱导分化第6 d时表达增加.在诱导分化第8 d,RXRα mRNA表达与第6 d相比差异不显著,直至终末分化. 脂肪细胞分化标志基因LPL在第2 d开始表达,第4和6 d逐步升高,在终末分化阶段仍保持高水平的表达;生脂基因PEPCK和SCD mRNA在第2和4 d开始表达,第6和8 d仍保持高水平的表达. 研究结果表明,100 μmol/L的Vit C促进猪前体脂肪细胞增殖能力最强;250 μmol/L Vit C能显著促进猪前体脂肪细胞分化. 其作用机制可能是通过对转录因子PPARγ和RXRα及标志基因LPL mRNA时序性表达的调控来进行的,促进生脂基因的表达,从而诱导脂肪细胞的分化.     

Postnatal differentiation of the Golgi apparatus and the dendrites of Purkinje cells of the rat cerebellum

Summary The morphology of postnatal differentiation of the Golgi apparatus, the nucleus, the perikaryon, and the dendrites was studied in Purkinje cells of the rat cerebellum for 30 days after birth using histochemical, histological, and electron microscopic methods.The Golgi apparatus during differentiation undergoes morphological and positional changes. From the 1st to 7th postnatal day, the Golgi apparatus is found in a supranuclear position, and is connected with the axes of differentiating primary dendrites by beam-like processes. From days 8 to 11 this connection disappears, and most of the Golgi apparatus assumes a lateronuclear and infranuclear position. After the 11th or 12th day, the Golgi apparatus is found in perinuclear and peripheral cytoplasmic positions. The formation of granular endoplasmic reticulum occurs in the vicinity of the perinuclear Golgi apparatus. The differentiation of cell and nuclear forms requires approximately 20 days. The morphological changes of differentiation are discussed in relation to the participation of the Golgi apparatus in the differentiation of dendrites and in the formation of the granular endoplasmic reticulum.     

The action of the cells of hemopoietic organs in chick embryos on mouse CFUdc and CLFUdc]

The humoral influence of cells of hemopoietic organs of chicken embryos of different terms on the development of the colony and cluster formation of mononuclears of the bone marrow of mice was studied in joint cultivation in two-compartment cylindrical diffuse microchambers. The process of formation of colonies and clusters is inhibited by cells of the yolk sac on the 2nd-4th day of the development, by cells of the liver on the 8th-12th day, of the spleen on the 13th-18th day and of the bone marrow--on the 15th day. The yolk sac cells were found to have most considerable inhibiting influence on proliferation and differentiation of cells on the 2nd day of the development of chicken embryo. The yolk sac cells on the 6th day stimulate the formation of colonies and clusters. The yolk sac, beginning from the 4th day of the development, and the liver release humoral factors promoting the formation of erythroid colonies. The erythroid colonies are formed but when cultivated on the vascular membrane of the chicken embryo; the erythroid colonies are not formed when cultivated in the abdominal cavity of mice. Local erythropoietinoid factors are not synthetized by the spleen and bone marrow cells. A supposition is put forward that a combination of the local inhibiting and erythropoietic effects promotes the erythroid differentiation of cells.     

Features of the development of the pituitary-thyroid system of the Wrangel Island hoofed lemming Dicrostonyx torquatus at stages of growth and peak population

By means of morphometric techniques, peculiarities in formation of the hypophyseal-thyroid system during prenatal and early postnatal periods have been studied in lemmings (Dicrostonyx torquatus) from the Wrangel island at growth stages and at the peak of the population quantity. Folliculoformation rate, time when the organ reaches the definitive structure, periods for establishing connection with the regulating center--the anterior hypophyseal lobe, correlation of differentiation rates of histo- and ultrastructures of the organ distinctly react to changes in the density population of the animals. Periods of initiation of folliculoformation are early and comparable at both stages of the population cycles. However, further at the peak of the population quantity, an essential retardation in the development of both histo- and ultrastructures of the thyroid cells is observed; formation of the histostructure significantly overtakes differentiation of the ultrastructures composing its cellular elements. The follicular structure begins to form only in newborn animals, the folliculogenesis completes on the 1st-6th days of the postnatal period. At the stage of growth of the population quantity, the folliculogenesis lasts 2 days (the 15th-17th days of the prenatal development), the organ's structure becomes definitive on the 17th day, at the same period connections are established with the anterior hypophyseal lobe. The role of the thyroid hormones in formation of reprodactive and adaptive potencies of the organism at various stages of the population cycle is discussed.     

The nucleus of the posterior pallial commissure in Lacerta sicula (Rafinesque) and its ontogenetic connection to the thalamus]

The nucleus of the posterior pallial commissure of Lacerta sicula originates between the 11th and 18day of incubation. During this time, the developing nucleus shows a distinct and wellformed cellular connection with the rostral, dorsally lying ventral thalamus. The whole connecting nuclear mass lies close to the matrix of the diencephalic and telencephalic ventricle and the connecting foramen interventriculare. It is evident that cells which originate from the the ventral thalamus are possibly delivered to the telencephalic nucleus of the posterior pallial commissure. The cellular connection between thalamus and hemisphere ruptures between the 18th and 19th day of incubation as a result of growth displacement and is no longer visible in later stages.     

Microspectrophotometric study of the lipid content in regenerating connective tissue

An experimental quantitative histological investigation was performed to study lipids in cellular elements of the regenerated connective tissue. Flap wounds were cut on the back of white mice and granulation tissue dissected 1, 3, 7, 14 30 and 60 days after the operation was investigated. Lipids and cellular elements were revealed with Sudan III-IV black B and Nile blue. Lipid quantity was estimated by means of a modified scanning integrating microphotometer. The greatest amount of lipids in the cellular elements of the granulation tissue was revealed on the 3d day of the experiment, total optic density (TOD) of lipids in leucocytes was 0.83, TOD in histiocytes--0.6. On the 7th day the amount of lipids decreased, their TOD in leucocytes was 0.6, in histiocytes--0.4. By the 14th day only phospholipids were revealed, in histiocytes their TOD was 0.3. In subsequent days phospholipid contents continued decreasing and by the 30th day their TOD was 0.2. By the 60th day, when a scar was formed in the wound, in fact, there were no lipids in the cellular elements. The microphotometric investigation performed demonstrated qualitative and quantitative characteristics of lipids in the cellular elements of the granulation tissue in dynamics and their close dependence on the time of wound healing. It was also revealed that the regenerative process was accompanied by decreasing lipid amount in the cellular elements, and this phenomenon could be used as a peculiar test to prognosticate the process of wound healing.     

The development of components of the blood-brain barrier in the neocortex of the white rat

In formation and differentiation of the hematoencephalic barrier elements in white non-inbred rats of 14 age groups (55 animals) at the ultrastructural level certain regular phases of the process have been revealed. For example, morphological maturation of endotheliocytes and pericytes occurs on the 7th day of the postnatal life. Maximal decrease in permeability of the hematoencephalic barrier takes place on the 10th day, as a consequence of liquidation of the pericapillary space between the basal membrane and the glial tunic of the capillaries. Morphofunctional maturation of the hematoencephalic barrier (the 21st day) terminates in differentiation of the pericapillary astrocytic limbs, that surround up to 85% of the capillary perimeter.     

Proteins of Developing Rice Embryos As Characterized by Twodimensional Gel Electrophoresis

Developmental changes of rice (Oryza sativa, subsp, japonica) in embryonic proteins during embryogenesis were investigated by modified two-dimensionalpolyacrylamide gel electrophoresis. The results indicated that there were apparently differences in the embryonic proteins between the embryos at 7th and 13th day after anthesis. Some proteins only appeared in the embryos al 7th day, disappearing at 13th day. Then some new proteinsappeared at 21th day embryos, which were different from that disappeared during differentiation. In concomitant with the completion of embryo differentiation, the number of acidic proteins decreased, while the basic ones showed an increasing trend. Itwas also found that in the 7th day embryos, there were a higher relative percent ofembryonic protein spots in the region of higher molecular weight, while in the 13thday there were higher relative percent of ones in the region of lower molecular weight.The electrophoretic pattern of rice germ lectin (RGL) showed that the synthesis ofRGL was associated with embryo differentiation. According to these results, we propose that some of embryonic proteins which areonly found at early stage of embryogenesis may be important factors for the regulationof embryo differentiation. Although the function of these proteins is still an openquestion, these specific proteins, at least, represent an excellent mark for plant embryodifferentiation.     

Variable expression of some "housekeeping" genes during human keratinocyte differentiation

We investigated the expression levels of four cellular "housekeeping" genes during epithelial differentiation. Differentiation is a dynamic process and various cellular RNAs have been targeted for use as internal controls during differentiation of human keratinocytes, but the consistent expression of such standards has not been previously validated. We used the organotypic (raft) culture system to grow stratified and differentiated epithelium in vitro. We compared cellular RNAs from epithelial tissues of both normal human keratinocytes and keratinocytes whose differentiation scheme is altered by the replication of human papillomavirus. Using ribonuclease protection assays to quantify RNA expression levels, we found that beta-actin and glyceraldehyde-3-phosphate dehydrogenase levels fluctuated during epithelial differentiation, whereas cyclophilin RNA and 28S-ribosomal RNA were the most consistently expressed during epithelial differentiation. These stably expressed cellular RNAs can be targeted as controls to permit quantitative expression analyses of cellular and pathogen RNAs during epithelial differentiation under various experimental conditions.