Partial purification and properties of γ-glutamyltranspeptidase from mycelia of Morchella esculenta

Three -glutamyltranspeptidase (enzymes I, II and III) were partially purified from the cell free extracts of the cultured mycelia of Morchella esculenta Fr. The molecular masses of enzymes were 155,000 (I), 219,000 (II) and 102,000 (III). All of them catalyzed both hydrolysis and transpeptidation of various -glutamyl compounds. -l-Glutamyl-cis-3-amino-l-proline occurring in the cultured mycelia of this fungus was a good substrate for both reactions. K _m values for hydrolysis were in the order of 10^-4 to 10^-5 M, and those for transpeptidation were in the order of 10^-2 to 10^-4 M. The enzymes were inhibited by a -glutamyltranspeptidase inhibitor, l-serine plus borate.Abbreviations -GTP -glutamyltranspeptidase - HPLC High-performance liquid chromatography     

Differentiation of Secondary Spermatogonia to Primary Spermatocytes by Mammalian Follicle-Stimulating Hormone in Organ Culture of Testes Fragments from the Newt, Cynops pyrrhogaster

In order to elucidate essential factors responsible for the initiation and promotion of spermatogenesis, we developed an organ culture system with a chemically defined medium. When newt testes fragments, consisting of somatic cells and germ cells almost exclusively secondary spermatogonia, were cultured in control medium for three weeks, most of the testicular cysts still contained only secondary spermatogonia. On the other hand, in the medium supplemented with various kinds of hormones and vitamins primary spermatocytes (zygotene-pachytene) appeared in about 60% of the cysts by the second week. Selective removal of specific hormones and vitamins revealed that follicle-stimulating hormone (FSH) alone was indispensable and sufficient for the differentiation of secondary spermatogonia to primary spermatocytes. Neither the addition of luteinizing hormone (LH) nor androgens (testosterone and 5α-dihydrotestosterone) to the control medium stimulated differentiation. Consistent with these findings was the fact that radioreceptor assays revealed high affinity specific binding sites for FSH but none for LH. Since our ultrastructural studies revealed a major loss of contact between spermatogonia and Sertoli cells following exposure to FSH, we suggest that FSH triggers differentiation of spermatogonia by acting on Sertoli cells which in turn act on spermatogonia.     

Distribution of isoasparagine among different characean species

Thirteen species of Characeae were analyzed for their free amino acid contents. Large amounts of isoasparagine, accounting for 10 to 50% of the total free amino acids, were found in extracts fromChara (5 species including one unidentified),Nitellopsis (1 species), andLamprothamnium (1 species). In contrast, no isoasparagine was detected inNitella (5 species) andTolypella (1 species), except forN. flexilis in which as much as 40% of the free amino acids was isoasparagine. Other major amino acids found in the tested materials were Ala, Asp, Glu and Gln.     

Differentiation of Primary Spermatocytes to Elongated Spermatids by Mammalian FSH in Organ Culture of Testes Fragments from the Newt, Cynops pyrrhogaster

Our previous studies (10, 11) showed that mammalian follicle-stimulating hormone (FSH) alone was indispensable and sufficient for the initiation and promotion of spermatogenesis from secondary spermatogonia to primary spermatocytes in organ culture of testes fragments from the newt, Cynops pyrrhogaster. The present study demonstrated that FSH promoted in the same model system the differentiation of primary spermatocytes even further: to the stage of elongated spermatids. When testes fragments, consisting of somatic cells and germ cells (mostly primary spermatocytes), were cultured in a control medium for three weeks, only round spermatids and spermatogonia were observed; both the diameter of the cysts and the viability of the germ cells decreased to about 10–15% of the original level. On the other hand, when the medium was supplemented with FSH, elongated spermatids appeared by the second week; both the diameter of the cysts and the viability of the germ cells were maintained at a higher level than in the control medium. The effect of FSH was dose-dependent. However, neither transferrin, androgens (testosterone and 5α-dihydrotestosterone) nor luteinizing hormone (LH) was effective. The addition of cyanoketone, a specific inhibitor of 3β-hydroxy-Δ⁵-steroid dehydrogenase (3β-HSD) (32), to the FSH-containing medium did not prevent the differentiation promoted by FSH, indicating that it is unlikely that Δ⁴-steroid metabolites produced in fragments by FSH acted directly on germ cells. Insulin was found to improve the viability of germ cells during a 2 week of culture period. In the presence of FSH, the cells in various differentiative stages had morphological characteristics very similar to those in vivo, whereas in the absence of FSH primary spermatocytes showed abnormal features in their nuclei and cytoplasm, indicating that they were deteriorating. These results and our previous results (1–3) suggest that FSH promotes primary spermatocytes to differentiate into elongated spermatids probably by stimulating Sertoli cells to secrete factors which then act on the germ cells.     

Sleep Apnea Syndrome (SAS) Clinical Practice Guidelines 2020

Sleep and Biological Rhythms - The prevalence of sleep-disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously...     

Distribution and genetic structure of the Japanese wood pigeon (Columba janthina) endemic to the islands of East Asia

The Japanese wood pigeon (Columba janthina) is endemic to the islands of East Asia and it is included in the Japanese and Asian Red Lists because of its narrow habitat range that is restricted to mature forests on small islands and because of the destruction of these habitats. We examined the genetic structure of Columba janthina by studying 463 base pairs of the mitochondrial control region sequences. We analyzed 154 samples from eight populations and identified 27 haplotypes. Three population groups were identified based on the pairwise Φ_ST values. A substantial gene flow, as reflected by the low and non-significant Φ_ST values, is maintained among the northern group that includes six populations found on the Okinawa, Tokara, Goto, Setouchi, Oki, and Izu islands. In contrast, the southeastern group found on the Ogasawara Islands had large Φ_ST values with every population from other regions (0.910 < Φ_ST < 0.962). The southwestern group found on the Sakishima Islands also had significant but small Φ_ST values with every population from the northern group (0.081 < Φ_ST < 0.205). The Mantel test showed a highly significant correlation between the Φ_ST values and the route length of the habitat network, as well as the linear distance with correction of the habitat gap effect, indicating the importance of the closely connected structure of the habitats. The three groups mentioned above could be considered as independent management units, and the southeastern group has the highest conservation priority due to its narrow distribution range and small population size. Electronic Supplementary Material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

Baculovirus-encoded protein BV/ODV-E26 determines tissue tropism and virulence in lepidopteran insects

Lepidopteran nucleopolyhedroviruses (NPVs) show distinct tissue tropism in host insect larvae. However, the molecular mechanism of this tropism is largely unknown. We quantitatively investigated NPV tissue tropism by measuring mRNA levels of viral genes in 16 tissues from Bombyx mori NPV (BmNPV)-infected B. mori larvae and found clear tissue tropism, i.e., BmNPV replicates poorly in the silk glands, midgut, and Malpighian tubule compared with other larval tissues. We next identified the viral genes determining tissue tropism in NPV infection by investigating the phenotypes of larvae infected with 44 BmNPV mutants in which one gene was functionally disrupted by a LacZ cassette insertion. We found that occlusion body (OB) production was markedly enhanced compared with that of the wild type in the middle silk glands (MSGs) of larvae infected with three mutants in which one of three tandemly arrayed genes (Bm7, Bm8, and Bm9) was disrupted. We generated additional mutants in which one or two genes of this gene cluster were partially deleted and showed that Bm8, also known as BV/ODV-E26, was solely required for the suppression of OB production in the MSGs of BmNPV-infected B. mori larvae. Western blotting showed that a LacZ cassette insertion in Bm7 or Bm9 resulted in aberrant expression of Bm8, presumably leading to abnormal OB production in the MSGs. Larval bioassays also revealed that disruption of Bm8 accelerated the death of B. mori larvae. These results suggest that the group I NPV-specific protein BV/ODV-E26 determines tissue tropism and virulence in host lepidopteran insects.     

The E1 protein of human papillomavirus type 16 is dispensable for maintenance replication of the viral genome

Papillomavirus genomes are thought to be amplified to about 100 copies per cell soon after infection, maintained constant at this level in basal cells, and amplified for viral production upon keratinocyte differentiation. To determine the requirement for E1 in viral DNA replication at different stages, an E1-defective mutant of the human papillomavirus 16 (HPV16) genome featuring a translation termination mutation in the E1 gene was used. The ability of the mutant HPV16 genome to replicate as nuclear episomes was monitored with or without exogenous expression of E1. Unlike the wild-type genome, the E1-defective HPV16 genome became established in human keratinocytes only as episomes in the presence of exogenous E1 expression. Once established, it could replicate with the same efficiency as the wild-type genome, even after the exogenous E1 was removed. However, upon calcium-induced keratinocyte differentiation, once again amplification was dependent on exogenous E1. These results demonstrate that the E1 protein is dispensable for maintenance replication but not for initial and productive replication of HPV16.