琵琶湖におけるヒガイ属魚類の起源と生態・形態分化

京都大学0048新制・課程博士博士(理学)甲第17774号理博第3897号新制||理||1562(附属図書館)30581京都大学大学院理学研究科生物科学専攻(主査)准教授 渡辺 勝敏, 教授 曽田 貞滋, 教授 疋田 努学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDGA

Phylogeny and historical demography of endemic fishes in Lake Biwa: the ancient lake as a promoter of evolution and diversification of freshwater fishes in western Japan

To elucidate the origins of the endemic fish of Lake Biwa, an ancient lake in Japan, and the role of the lake in the diversification of freshwater fish in western Japan, we established a molecular phylogenetic framework with an absolute time scale and inferred the historical demography of a large set of fish species in and around the lake. We used mtDNA sequences obtained from a total of 190 specimens, including 11 endemic species of Lake Biwa and their related species, for phylogenetic analyses with divergence time estimations and from a total of 2319 specimens of 42 species (including 14 endemics) occurring in the lake for population genetic analyses. Phylogenetic analysis suggested that some of the endemic species diverged from their closest relatives earlier (1.3-13.0 Ma) than the period in which the present environmental characteristics of the lake started to develop (ca. 0.4 Ma), whereas others diverged more recently (after 0.4 Ma). In contrast, historical demographic parameters suggested that almost all species, including endemic and nonendemic ones, expanded their populations after the development of the present lake environment. In phylogeographic analyses, common or very close haplotypes of some species were obtained from Lake Biwa and other regions of western Japan. The phylogenetic and historical demographic evidence suggests that there was a time lag between phylogenetic divergence and population establishment and that phenotypic adaptation of some endemic species to the limnetic environment occurred much later than the divergences of those endemic lineages. Population structure and phylogeographic patterns suggest that Lake Biwa has functioned not only as the center of adaptive evolution but also as a reservoir for fish diversity in western Japan

Updates in the Clinical Development of Epacadostat and Other Indoleamine 2,3-Dioxygenase 1 Inhibitors (IDO1) for Human Cancers

Recent application of immunotherapy in clinical oncology revolutionized our management of advanced human cancers. Check point inhibitors targeting CTLA4 and PD-1/PD-L1 axis are immunotherapeutic agents currently available to treat a variety of cancers. However, a novel therapeutic approach is needed to further improve patient outcome with these agents. Indoleamine 2,3-dioxygenase 1 (IDO1) is a rate-limiting enzyme in the metabolism of essential amino acid tryptophan in the peripheral tissue. IDO1 is overexpressed in human cancer cells and suppresses effector T cell function and promotes regulatory T cells (Tregs). Overexpression of IDO1 is associated with poor patient survival in several types of human cancer. These findings indicate that IDO1 is a promising target that can improve the treatment outcome in the field of Immuno-oncology. Several orally available IDO1 inhibitors including Epacadostat have entered human clinical trials over the last few years without a major safety concern. Although there is no objective response in single-agent trials, combination regimens with PD-1 inhibitors appear to exceed the activity of PD-1 inhibitors alone. Recent phase III ECHO 301 trial testing the combination of Epacadostat with Pembrolizumab in melanoma did not show superior outcome compared to Pembrolizumab alone. This lead to halting of other phase III trials using IDO1 inhibitors. In this minireview, we will discuss the recent clinical development of Epacadostat and other IDO1 inhibitors

A Novel Resource Polymorphism in Fish, Driven by Differential Bottom Environments: An Example from an Ancient Lake in Japan

Divergent natural selection rooted in differential resource use can generate and maintain intraspecific eco-morphological divergence (i.e., resource polymorphism), ultimately leading to population splitting and speciation. Differing bottom environments create lake habitats with different benthos communities, which may cause selection in benthivorous fishes. Here, we document the nature of eco-morphological and genetic divergence among local populations of the Japanese gudgeon Sarcocheilichthys (Cyprinidae), which inhabits contrasting habitats in the littoral zones (rocky vs. pebbly habitats) in Lake Biwa, a representative ancient lake in East Asia. Eco-morphological analyses revealed that Sarcocheilichthys variegatus microoculus from rocky and pebbly zones differed in morphology and diet, and that populations from rocky environments had longer heads and deeper bodies, which are expected to be advantageous for capturing cryptic and/or attached prey in structurally complex, rocky habitats. Sarcocheilichthys biwaensis, a rock-dwelling specialist, exhibited similar morphologies to the sympatric congener, S. v. microoculus, except for body/fin coloration. Genetic analyses based on mitochondrial and nuclear microsatellite DNA data revealed no clear genetic differentiation among local populations within/between the gudgeon species. Although the morphogenetic factors that contribute to morphological divergence remain unclear, our results suggest that the gudgeon populations in Lake Biwa show a state of resource polymorphism associated with differences in the bottom environment. This is a novel example of resource polymorphism in fish within an Asian ancient lake, emphasizing the importance and generality of feeding adaptation as an evolutionary mechanism that generates morphological diversification

Multiple colonizations of Lake Biwa by Sarcocheilichthys fishes and their population history

Rapid adaptation and speciation have not been well documented for organisms in Lake Biwa, Japan, the oldest ancient lake in East Asia. To examine these processes, we focused on the divergence of Sarcocheilichthys gudgeons and conducted phylogeographic and population genetic analyses using mitochondrial DNA sequences and microsatellite data. No remarkable genetic differentiation was found between two species, S. biwaensis and S. variegatus microoculus, both endemic to Lake Biwa, whereas this species group, including S. v. variegatus, was genetically divided into three major regional groups: the Lake Biwa, Ise Bay, and western groups. Divergent mtDNA haplotypes were included within the Lake Biwa and western groups, strongly suggesting secondary contacts among allopatrically isolated populations. Dating for mtDNA phylogeny using a geological constraint suggested the colonization of Lake Biwa by multiple Sarcocheilichthys lineages that diverged from each other in the early–middle Pleistocene. Coalescent-based population analyses indicated that the local populations colonized the rocky bottom habitat in Lake Biwa from other habitats after the Last Glacial Maximum, likely reflecting past environmental changes in the lake, including the disappearance of rocky areas during the glacial climate. Divergent morphological adaptation in Sarcocheilichthys associated with substrate type may have rapidly proceeded along with environmental changes

Image_3_Clinical impact of number of lymph nodes dissected on postoperative survival in node-negative small cell lung cancer.tif

ObjectivesSmall cell lung cancer (SCLC) is a lethal histologic subtype of lung cancer. Although the Commission on Cancer recommends pathological examination of at least 10 lymph nodes dissected (LNDs) for resected early-stage non-small cell lung cancer, its survival benefit of LNDs in patients with early-stage SCLC is unknown.MethodsThe National Cancer Database was queried for SCLC patients with clinical stage I-II and clinical N0, NX disease per AJCC 7th edition who had undergone lobectomy between 2004 and 2017. Overall survival of SCLC patients by the number of LNDs was compared using Log-rank tests. Univariate and multivariable Cox proportional hazards analyses were performed.ResultsIn total, 688 (42%), 311 (20%), 247 (16%), 196 (12%), 126 (8%), and 36 (2%) of 1,584 patients with early-stage SCLC had ≥10, 7-9, 5-6, 3-4, 1-2, and 0 LNDs, respectively. The sequential improvement in the HRs was no longer evident if the number of LNDs exceeds 4. Patients with ≥3 LNDs (n = 1,422) had a significantly longer overall survival than those with ConclusionsAlthough we are reluctant to recommend a definitive “optimal number” of LNDs, our findings suggest the prognostic and therapeutic roles for performing ≥3 LNDs in patients with early-stage SCLC who undergo lobectomy.</p

Image_4_Clinical impact of number of lymph nodes dissected on postoperative survival in node-negative small cell lung cancer.tif

ObjectivesSmall cell lung cancer (SCLC) is a lethal histologic subtype of lung cancer. Although the Commission on Cancer recommends pathological examination of at least 10 lymph nodes dissected (LNDs) for resected early-stage non-small cell lung cancer, its survival benefit of LNDs in patients with early-stage SCLC is unknown.MethodsThe National Cancer Database was queried for SCLC patients with clinical stage I-II and clinical N0, NX disease per AJCC 7th edition who had undergone lobectomy between 2004 and 2017. Overall survival of SCLC patients by the number of LNDs was compared using Log-rank tests. Univariate and multivariable Cox proportional hazards analyses were performed.ResultsIn total, 688 (42%), 311 (20%), 247 (16%), 196 (12%), 126 (8%), and 36 (2%) of 1,584 patients with early-stage SCLC had ≥10, 7-9, 5-6, 3-4, 1-2, and 0 LNDs, respectively. The sequential improvement in the HRs was no longer evident if the number of LNDs exceeds 4. Patients with ≥3 LNDs (n = 1,422) had a significantly longer overall survival than those with ConclusionsAlthough we are reluctant to recommend a definitive “optimal number” of LNDs, our findings suggest the prognostic and therapeutic roles for performing ≥3 LNDs in patients with early-stage SCLC who undergo lobectomy.</p

Image_2_Clinical impact of number of lymph nodes dissected on postoperative survival in node-negative small cell lung cancer.tif

ObjectivesSmall cell lung cancer (SCLC) is a lethal histologic subtype of lung cancer. Although the Commission on Cancer recommends pathological examination of at least 10 lymph nodes dissected (LNDs) for resected early-stage non-small cell lung cancer, its survival benefit of LNDs in patients with early-stage SCLC is unknown.MethodsThe National Cancer Database was queried for SCLC patients with clinical stage I-II and clinical N0, NX disease per AJCC 7th edition who had undergone lobectomy between 2004 and 2017. Overall survival of SCLC patients by the number of LNDs was compared using Log-rank tests. Univariate and multivariable Cox proportional hazards analyses were performed.ResultsIn total, 688 (42%), 311 (20%), 247 (16%), 196 (12%), 126 (8%), and 36 (2%) of 1,584 patients with early-stage SCLC had ≥10, 7-9, 5-6, 3-4, 1-2, and 0 LNDs, respectively. The sequential improvement in the HRs was no longer evident if the number of LNDs exceeds 4. Patients with ≥3 LNDs (n = 1,422) had a significantly longer overall survival than those with ConclusionsAlthough we are reluctant to recommend a definitive “optimal number” of LNDs, our findings suggest the prognostic and therapeutic roles for performing ≥3 LNDs in patients with early-stage SCLC who undergo lobectomy.</p

Image_5_Clinical impact of number of lymph nodes dissected on postoperative survival in node-negative small cell lung cancer.tif

ObjectivesSmall cell lung cancer (SCLC) is a lethal histologic subtype of lung cancer. Although the Commission on Cancer recommends pathological examination of at least 10 lymph nodes dissected (LNDs) for resected early-stage non-small cell lung cancer, its survival benefit of LNDs in patients with early-stage SCLC is unknown.MethodsThe National Cancer Database was queried for SCLC patients with clinical stage I-II and clinical N0, NX disease per AJCC 7th edition who had undergone lobectomy between 2004 and 2017. Overall survival of SCLC patients by the number of LNDs was compared using Log-rank tests. Univariate and multivariable Cox proportional hazards analyses were performed.ResultsIn total, 688 (42%), 311 (20%), 247 (16%), 196 (12%), 126 (8%), and 36 (2%) of 1,584 patients with early-stage SCLC had ≥10, 7-9, 5-6, 3-4, 1-2, and 0 LNDs, respectively. The sequential improvement in the HRs was no longer evident if the number of LNDs exceeds 4. Patients with ≥3 LNDs (n = 1,422) had a significantly longer overall survival than those with ConclusionsAlthough we are reluctant to recommend a definitive “optimal number” of LNDs, our findings suggest the prognostic and therapeutic roles for performing ≥3 LNDs in patients with early-stage SCLC who undergo lobectomy.</p