Development of the ultrastructural organization of the rat neurohypophysis during postnatal ontogenesis

The development of structural components of the posterior hypopysis lobe of rats, the development of the neurosecretory activity of the hypothalamo-hypophyseal nervous system and the establishment of its function as a single system within the first three weeks after birth (1, 7, 14 and 21 days) as well as embryos of the 20th and 21st days of development were studied electron-microscopically. It has been established that the pituicytes of the posterior lobe of the hypophysis of newborn rats are represented by a single type of cells and are completely differentiated. On the 21st day they are in different morpho-functional states and consist of dark and light cells. By the 14th day of development a considerably increased amount of the neurosecretion is observed. By the 21st day the density of neurosecretion granules per a preparation unit does not change. The basal layer of the capillaries is formed not definitely by the birth time; on the 14th day the organization of the vessel wall is almost similar to that of mature animals. The Herring bodies make their appearance on the 21st day after birth. The hypothalamus and neurohypophysis of rats are functionally active before birth. After birth their neurosecretion activity is well pronounced while the hypothalamo-hypophyseal nervous system is not mature yet. By the time of getting sight this system is almost formed and sufficiently active.     

Adverse effects on offspring of maternal alcohol abuse during pregnancy

To evaluate the risk of offspring of heavy drinking during pregnancy, we administered a questionnaire to 633 women at the first prenatal visit. Nutritional status, smoking, drug and alcohol use were determined. Women were classified into three groups: abstinent and rare drinkers; moderate drinkers; and heavy drinkers. After delivery, detailed pediatric, neurologic and developmental examinations were administered by a physician without prior knowledge of any history. Infants born to heavy drinkers had twice the risk of abnormality of those born to abstinent or moderate drinkers (P less than 0.001). Thirty-two per cent of infants born to heavy drinkers demonstrated congenital anomalies, as compared to 9 per cent in the abstinent and 14 per cent in the moderate group (P less than 0.001). Microcephaly and multiple congenital anomalies were much more frequent in this group (P less than 0.001). Heavy drinking during pregnancy increases the risk to offspring.     

Dissociation of prelycopersene pyrophosphate synthetase from phytoene synthetase complex of tomato fruit plastids

The partially purified phytoene synthetase enzyme complex obtained from tomato fruit plastids dissociates into two or more subunit species on chromatography in low ionic strength buffer on DEAE-cellulose. One of these subunits prelycopersene pyrophosphate synthetase, has a molecular weight of approximately 40,000, whereas the phytoene synthetase complex has a molecular weight of 200,000. The prelycopersene pyrophosphate synthetase catalyzes the conversion of isopentenyl pyrophosphate to geranylgeranyl and prelycopersene pyrophosphates. The identities of these substances were established by thin layer chromatography in several solvent systems. The formation of both geranylgeranyl and prelycopersene pyrophosphates by this enzyme supports earlier results with cruder enzyme systems which suggested that these compounds are intermediates in the synthesis of phytoene.     

Secretory immunoglobulin A in the blood sera of healthy and ill persons

Sera of healthy and sick persons were tested for the presence of secretory IgA (SIgA) and free secretory component (SC) SIgA was present in the blood of healthy persons in low concentrations (1.07 mg/100 mg), and free SC was absent. Infectious and somatic diseases, in which damage of the epithelial covering of the gastrointestinal and respriatory tracts was possible, were accompanied by increased blood SIgA content. There was also noted a distinct relationship between the blood SIgA concentration and the severity of infectious diseases and pneumonia supervention. In these cases the SIgA level proved to rise.     

Evidence for dosage compensation in parthenogenetic Hymenoptera

Amounts of DNA-Feulgen staining in individual somatic nuclei and mature sperm of the parthenogenetic wasps, Habrobracon juglandis, H. serinopae, and Mormoniella vitripennis, were determined with a scanning microdensitometer. The haploid genome for both species of Habrobracon was estimated to be 0.15-0.16 X 10-(12) gDNA, corresponding to a molecular weight of roughly 10 X10(10) daltons. The haploid genome of M. vitripennis is approximately twice this value, 0.33-0.34 X 10-(12) g, or about 20X10(10) daltons. Measurements made on dividing nuclei from syncytial preblastoderm embryos of H. juglandis and M. viripennis showed that the chromosomes of impaternate males were present in the haploid number and contained the C amount of DNA; whereas nuclei from female preblastoderm embryos contained the diploid number of chromosomes and the 2C amount of DNA. However, hemocyte and brain cell nuclei from either male or female adult wasps contained 2C and 4C amounts of DNA. Both sexes also showed equivalent levels of polyploidy (8C, 16C, or 32C) in Malpighian tubule nuclei. Therefore, in these parthenogenetic species,, a mechanism must exist the compensates during later development for the initial two-fold difference in the chromatin content of somatic nuclei in haploid male and diploid female embryos. Hemocytes from impaternate Mormoniella diploid males and triploid females contain the 2C and 3C amounts of DNA, respectively Therefore dosage compensation involves an additional cycle of DNA replication only in hapoid cells, and it insures that a certain minimum quantity of DNA is received by each somatic cell.