Synthesis of 6-Sulfur Analogues of Oxanosine and Closely Related Derivatives Thereof

Abstract

Novel β-D-ribofuranosides having a 5-substituted imidazo [4,5-d] [1,3]thiazine ring, including the S⁶-congener 3 of oxanosine 2, were synthesized for screening their anticancer and antiviral activities.     

Comparative studies on immunochemical properties of female-specific serum protein and egg yolk proteins in rainbow trout (Salmo gairdneri).

1. Female-specific serum protein (FS) and egg yolk proteins of mature female rainbow trout (Salmo gairdneri) were studied comparatively with reference to their immunological and some physicochemical properties. 2. FS was considered to be composed of two egg proteins, E1 and E2, which were isolated from the egg yolk by gel filtration. 3. The molecular weights of FS, E1 and E2 were estimated by gel filtration to be approx 600,000, 300,000 and 35,000, respectively. 4. The analysis with sodium dodecyl sulphate electrophoresis indicated that E1 consisted of two subunits with molecular weights of 90,000 and 15,000, and E2 was estimated to be a dimer of a molecule of 15,000. 5. Male and immature female trout were injected with estradiol-17 beta, and the production of proteins with the same antigenicity with FS was demonstrated.     

Comparative study on amino acid sequences of Kunitz-type soybean trypsin inhibitors, Tia, Tib, and Tic

The amino acid sequences of three variants of the Kunitz-type trypsin inhibitors, Tia, Tib, and Tic, obtained from some cultivars of soybean were determined by conventional methods. All three inhibitors consisted of 181 amino acid residues. The differences in the amino acid sequences are as follows: Tia E12 G55 Y62 H71 S74 M114 L120 P137 L176; Tib S F N R V I T V; Tic E. The amino acid sequences of Pro(60)-Ser(61) and Asp(154)-Asp(155)-Gly(156)-His(157) of Tia reported previously (Koide & Ikenaka (1973) Eur. J. Biochem. 32, 417-431) were amended to Ser(60)-Pro(61) and His(154)-Asp-Asp-Gly(157), respectively.     

Histoenzymatic and ultrastructural changes in the hepatocytes of gamma-irradiated rabbits.

Ultrastructural changes and intracellular enzyme activities in the hepatocytes were studied in rabbits irradiated with 550 rads of gamma rays at 1,3,6,9,15 and 30 days after irradiation. Swelling and marked rarefaction of the mitochondrial matrix observed on the first day were followed by gradual condensation of the matrix between the 6th and 9th day. This state was accompanied by marked reduction in the succinate dehydrogenase activity, ehich gradually returned to the normal by the 30th day of observation. In the hyaloplasm, the most intense changes developed between the third and sixth day and were manifested by clearing of the cytoplasm and marked fragmentation of the endoplasmic membranes, with concurrent negligible decline of the lactate dehydrogenase activity and unchanged glucose-6-phosphatase activity. In the Golgi apparatus, vacuolization of the cytoplasm and fragmentation of smooth membranes were most pronounced on the 6th day and were correlated with a weakened and diffuse reaction for thiamine pyrophosphatase. The alkaline phosphatase activity was irregularly distributed in the lobule. The activities of lysosomal hydrolases, i.e. acid phosphatase, beta-glucuronidase and non-specific esterase, had various localizations within the lobules. The strongest deviations from the normal and of longest duration. (up to 9 days) were seen in the Browicz-Kupffer cells. Complex studies on the same material conducted concurrently with the use of different methods showed that radiation damages structure and function in unequal degrees. Moreover, within the same organ the cellular response to ionizing radiation varies according to the character, localization and functional state of the cells. Deviations from the normal state occur between the first and ninth days, most of the structural and functional elements showing sings of return to the normal about the 15th day after irradiation.     

Physiological polyspermy: Selection of a sperm nucleus for the development of diploid genomes in amphibians

The union between a sperm and an egg nucleus in egg fertilization is necessary to mix genetic materials to create a new diploid genome for the next generation. In most animals, only one sperm is incorporated into the egg (monospermy), but several animals exhibit physiological polyspermy in which several sperms enter the egg during normal fertilization. However, only one sperm nucleus forms the zygote nucleus with the egg nucleus, even in a polyspermic egg. The cellular and molecular mechanisms involved in the selection of sperm nuclei in the egg cytoplasm have been well investigated in urodele amphibians. The principal sperm nucleus develops a larger sperm aster and contacts the egg nucleus to form a zygote nucleus, whereas other accessory sperm nuclei are unable to approach the egg nucleus. The diploid zygote nucleus induces cleavage and participates in embryonic development, whereas the accessory sperm nuclei undergo pyknosis and degenerate. We propose several models to account for the mechanisms of the selection of one sperm nucleus and the degeneration of accessory sperm nuclei. The roles of physiological polyspermy in animal reproduction are discussed by comparison with other polyspermic species.     

DNA content contributes to nuclear size control in Xenopus laevis

Cells adapt to drastic changes in genome quantity during evolution and cell division by adjusting the nuclear size to exert genomic functions. However, the mechanism by which DNA content within the nucleus contributes to controlling the nuclear size remains unclear. Here, we experimentally evaluated the effects of DNA content by utilizing cell-free Xenopus egg extracts and imaging of in vivo embryos. Upon manipulation of DNA content while maintaining cytoplasmic effects constant, both plateau size and expansion speed of the nucleus correlated highly with DNA content. We also found that nuclear expansion dynamics was altered when chromatin interaction with the nuclear envelope or chromatin condensation was manipulated while maintaining DNA content constant. Furthermore, excess membrane accumulated on the nuclear surface when the DNA content was low. These results clearly demonstrate that nuclear expansion is determined not only by cytoplasmic membrane supply but also by the physical properties of chromatin, including DNA quantity and chromatin structure within the nucleus, rather than the coding sequences themselves. In controlling the dynamics of nuclear expansion, we propose that chromatin interaction with the nuclear envelope plays a role in transmitting chromatin repulsion forces to the nuclear membrane.     

Caring for US Children: Barriers to Effective Treatment in Children with the Disease of Obesity

In 2020, impediments to pediatric obesity (PO) treatment remain pervasive, even though these barriers are clearly documented in medical literature. Providers must invest considerable resources to overcome these barriers to care. Notable barriers include gaps in medical education, misperceptions of the disease, weight bias and stigma, exclusion of coverage in health plans, and thus an unsustainable financial framework. Hence, this review offers an updated social‐ecological framework of accessibility to care, wherein each barrier to care or variable is interdependent on the other and each is critical to creating forward momentum. The sum of all these variables is instrumental to overall smooth function, configured as a wheel. To treat PO effectively, all variables must be adequately addressed by stakeholders throughout the health care system in order to holistically comprehend and appreciate undertakings to advance the burgeoning field of PO medicine.     

Phylogeography of Fischer’s blue,Tongeia fischeri,in Japan: Evidence for introgressive hybridization

The widespread lycaenid butterfly Tongeia fischeri is distributed from eastern Europe to northeastern Asia and represented by three geographically isolated populations in Japan. In order to clarify the phylogeographic history of the species, we used sequences of three mitochondrial (COI, Cyt b and ND5) and two nuclear (Rpl5 and Ldh) genes of 207 individuals collected from 55 sites throughout Japan and five sites on the Asian continent. Phylogenetic trees and the median-joining network revealed six evolutionary mitochondrial haplotype clades, which corresponded to the geographic distribution of the species. Common ancestors of Japanese T. fischeri might have come to Japan during the mid-Pleistocene by multiple dispersals of continental populations, probably via a land bridge or narrow channel between western Japan and the Korean Peninsula. The geographical patterns of variation of mitochondrial and nuclear markers are discordant in northeastern Kyushu, possibly as a result of introgressive hybridization during the ancient contact between the Kyushu and Shikoku populations in the last glacial maximum. The phylogeographic pattern of T. fischeri in Japan are probably related to the geological history, Pleistocene climatic oscillations and distribution of the host plant.