Cloning of the gene for the thyrotropin beta subunit in the Japanese crested ibis,Nipponia nippon

We isolated a putative gene for the thyrotropin beta subunit (TSHbeta) from two types of genomic libraries of the Japanese crested ibis, Nipponia nippon. Exon-intron structure was deduced by comparing the determined sequence with those of TSH beta cDNA of other birds. The deduced amino acid sequence shows extensive similarities to those of the other birds, which assures our assumption that the acquired nucleotide sequence represents the TSHbeta gene. The assembled genomic fragment is 4192 bp in size and consists of 1937 bp of putative 5' flanking region followed by exon-intron structure with three exons and two introns, similar to those observed in rat, human and goldfish counterparts. Locations of introns are also similar to those in mammals and goldfish. Comparison of the 5' flanking region of the ibis TSHbeta gene with those of mammals reveals that several regulatory sequences, such as negative thyroid hormone responsive element (nTRE), Pit-1 responsive element, and AP-1 responsive element, which were characterized in mammalian TSHbeta genes, are also found in the promoter region. This is the first report on the exon-intron structure and 5' flanking region of the TSHbeta gene in an avian species.     

Phylogenetic Position of the Subgenus Lordiphosa of the Genus Drosophila (Diptera: Drosophilidae) Inferred from Alcohol Dehydrogenase (Adh) Gene Sequences

We analyzed the phylogenetic relationship between the species of Lordiphosa and other Drosophilidae using alcohol dehydrogenase (Adh) gene sequences. The phylogenetic trees consistently show that the four species Drosophila kurokawai, D. collinella, D. stackelbergi, and D. clarofinis, which include three species groups of Lordiphosa, form a monophyletic clade. This clade is placed as a sister group to the willistoni and saltans groups of Sophophora. On the other hand, three species of Lordiphosa, D. tenuicauda, D. pseudotenuicauda, and D. acutissima, all of which belong to the tenuicauda group, are not shown to be related to the major Lordiphosa lineage. In the phylogenetic trees, these species are included into the clade comprised of Drosophila and Hirtodrosophila, although it remains uncertain whether the tenuicauda group is a monophyletic group or not. These results indicate that Lordiphosa is polyphyletic and that most of the members of the subgenus have a close relationship to the neotropical groups of Sophophora. The above conclusion is compatible with the hypothesis of Okada (Mushi [1963] 37:79–100) and Lastovka and Máca (Acta Ent Bohemoslov [1978] 75:404–420) that Lordiphosa is most closely related to Sophophora; in contrast, our results contradict the hypothesis of Grimaldi (Bull Am Mus Nat Hist [1990] 197:1–139) that Lordiphosa is a sister group to the genus Scaptomyza. Received: 12 May 1999 / Accepted: 14 April 2000     

Sexual dimorphism and courtship behavior in Drosophila prolongata

Sexual dimorphism is often derived from sexual selection. In sexually dimorphic Drosophila species, exaggerated male structures are used for specific behaviors in male-to-male competition or courtship toward females. In Drosophila prolongata, a member of the melanogaster species group, males have enlarged forelegs whereas females do not. However, the adaptive role of the enlarged forelegs is unclear because little is known about the behavior of D. prolongata. In this study, the courtship behavior of D. prolongata was investigated in comparison with closely related species. Males of D. prolongata use their forelegs in a specific behavior, “leg vibration”, in which the male vigorously vibrates the female’s abdomen by extending his forelegs from in front of her. Leg vibration was observed immediately before “attempting copulation”, indicating that it has an adaptive role in the mating process. In contrast, leg vibration was not observed in closely related species. Because the large forelegs are necessary to accomplish leg vibration, it was suggested that the sexual dimorphism of D. prolongata forelegs is currently under the influence of sexual selection in courtship behavior.     

Suppression of lipoprotein lipase in 3T3-L1 cells by a mediator produced by SEKI melanoma, a cachexia-inducing human melanoma cell line

Production of a cachexia-inducing factor(s) by the SEKI melanoma cell line, established from a human melanoma, has been well documented. Conditioned medium from cultures of this melanoma cell line contains a factor(s) that inhibits the activity of lipoprotein lipase (LPL) in fully differentiated 3T3-L1 adipocytes. The mode of inhibition of this enzyme by the factor, i.e. its dose-dependency and time course, is very similar to that of LPL-inhibition by a macrophage-derived cachexia-inducing factor, cachectin/tumor necrosis factor (cachectin/TNF). However, the conditioned medium of SEKI melanoma cells does not contain any immuno-reactive substances reactive in enzyme-linked immunosorbent assay (ELISA) with anti-cachectin/TNF antibody, or with anti-interleukin 1 alpha or beta antibodies. This LPL-suppression factor present in the conditioned medium seems to be a peptide because of its heat-lability and apparent molecular weight of more than 25,000. The conditioned media from cultures of four other different cell lines were found to show no significant suppression of LPL activity. These results imply that SEKI melanoma cells produce a cachexia-inducing factor(s) similar to cachectin/TNF but that the molecule involved is different.     

The Drosophila obscura species-group (Diptera,Drosophilidae) from Yunnan Province,Southern China

Three new and two known species of the Drosophila (Sophophora) obscura species-group are reported from Yunnan Province, southern China. The sinobscura species-subgroup is newly established by D. sinobscura, D. hubeiensis and D. luguensis sp. nov. Geographic distribution of the obscura group in and around China is discussed, and a key to 10 Chinese species of the obscura group is provided.     

Cloning of the genes for the pituitary glycoprotein hormone alpha and follicle-stimulating hormone beta subunits in the Japanese crested ibis,Nipponia nippon

We have isolated a part of the gene for the pituitary glycoprotein hormone common alpha subunit (PGHalpha) and the whole gene for the follicle-stimulating hormone beta subunit (FSHbeta) in the Japanese crested ibis (Nipponia nippon), a critically endangered bird species in East Asia. The nucleotide sequence of a part of the PGHalpha gene (5026 bp) contained three exons holding the whole coding and 3' untranslated regions, but lacked a 5' untranslated region. Its exon-intron structure was similar to that in mammals, but different from that in teleosts in the location of the second intron. For the FSHbeta gene, the nucleotide sequence of 7633 bp was assembled from two phage clones. The exon-intron structure of three exons and two introns was similar to that observed in mammals and teleosts. In the putative promoter region of the ibis FSHbeta gene, a progesterone responsive element (PRE)-like sequence and two AP-1 responsive element-like sequences reported in the ovine FSHbeta gene were not conserved in complete form. The increased number of ATTTA motifs in the putative 3' untranslated region in comparison with those in Japanese quail and chicken FSHbeta cDNA suggested that more rapid degradation of FSHbeta mRNA occurs in this species. Deduced amino acid sequences of the ibis PGHalpha and FSHbeta showed high similarities with those of the corresponding subunits of other avian species. This is the first report on the genomic sequences of the PGHalpha and FSHbeta in an avian species.     

Isolation of a cotton CAP gene: a homologue of adenylyl cyclase-associated protein highly expressed during fiber elongation

The cDNA encoding CAP (adenylyl cyclase-associated protein) was isolated from a cotton (Gossypium hirsutum) fiber cDNA library. The cDNA (GhCAP) contained an open reading frame that encoded 471 amino acid residues. RNA blot analysis showed that the cotton CAP gene was expressed mainly in young fibers.     

Replication origin of mitochondrial DNA in insects

The precise position of the replication origin (O(R)) of mtDNA was determined for insect species belonging to four different orders (four species of Drosophila, Bombyx mori, Triborium castaneum, and Locusta migratoria, which belong to Diptera, Lepidoptera, Coleoptera, and Orthoptera, respectively). Since the free 5' ends of the DNA strands of mtDNA are interpreted as the O(R), their positions were mapped at 1-nucleotide resolution within the A + T-rich region by using the ligation-mediated PCR method. In all species examined, the free 5' ends were found within a very narrow range of several nucleotides in the A + T-rich region. For four species of Drosophila, B. mori, and T. castaneum, which belong to holometabolous insects, although the O(R)'s were located at different positions, they were located immediately downstream of a series of thymine nucleotides, the so-called T-stretch. These results strongly indicate that the T-stretch is involved in the recognition of the O(R) of mtDNA at least among holometabolous insects. For L. migratoria (hemimetabolous insect), on the other hand, none of the long stretches of T's was found in the upstream portion of the O(R), suggesting that the regulatory sequences involved in the replication initiation process have changed through insect evolution.