pmar1/phb homeobox genes and the evolution of the double-negative gate for endomesoderm specification in echinoderms.

In several model animals, the earliest phases of embryogenesis are regulated by lineage-specific genes, such as Drosophila bicoid Sea urchin (echinoid) embryogenesis is initiated by zygotic expression of pmar1, a paired-class homeobox gene that has been considered to be present only in the lineage of modern urchins (euechinoids). In euechinoids, Pmar1 promotes endomesoderm specification by repressing the hairy and enhancer of split C (hesC) gene. Here, we have identified the basal echinoid (cidaroid) pmar1 gene, which also promotes endomesoderm specification but not by repressing hesC A further search for related genes demonstrated that other echinoderms have pmar1-related genes named phb Functional analyses of starfish Phb proteins indicated that, similar to cidaroid Pmar1, they promote activation of endomesoderm regulatory gene orthologs via an unknown repressor that is not HesC. Based on these results, we propose that Pmar1 may have recapitulated the regulatory function of Phb during the early diversification of echinoids and that the additional repressor HesC was placed under the control of Pmar1 in the euechinoid lineage. This case provides an exceptional model for understanding how early developmental processes diverge.

Dual role of Jam3b in early hematopoietic and vascular development.

In order to efficiently derive hematopoietic stem cells (HSCs) from pluripotent precursors, it is crucial to understand how mesodermal cells acquire hematopoietic and endothelial identities: two divergent, but closely related, cell fates. Although Npas4 has been recently identified as a conserved master regulator of hemato-vascular development, the molecular mechanisms underlying cell fate divergence between hematopoietic and vascular endothelial cells are still unclear. Here, we show in zebrafish that mesodermal cell differentiation into hematopoietic and vascular endothelial cells is regulated by Junctional adhesion molecule 3b (Jam3b) via two independent signaling pathways. Mutation of jam3b led to a reduction in npas4l expression in the posterior lateral plate mesoderm and defects in both hematopoietic and vascular development. Mechanistically, we show that Jam3b promotes endothelial specification by regulating npas4l expression through repression of the Rap1a-Erk signaling cascade. Jam3b subsequently promotes hematopoietic development, including HSCs, by regulating lrrc15 expression in endothelial precursors through the activation of an integrin-dependent signaling cascade. Our data provide insight into the divergent mechanisms for instructing hematopoietic or vascular fates from mesodermal cells.

Melatonin suppresses both osteoblast and osteoclast differentiation through repression of epidermal Erk signaling in the zebrafish scale.

Melatonin has been implicated in the regulation of bone metabolism; however, the molecular mechanisms underlying its involvement in fracture healing are still obscure. We previously developed an in vivo fracture healing model using the scale of a double-transgenic zebrafish, trap:GFP; osterix:mCherry, which labels osteoclasts and osteoblasts with GFP and mCherry, respectively. Here we show using this model that melatonin inhibits both osteoblast and osteoclast differentiation under fracture stress through the repression of Erk signaling in epidermal cells of the scale. Melatonin treatment resulted in reduced numbers of both osteoblasts and osteoclasts in the fractured scale. Immunochemistry analysis revealed that Erk signals in epidermal cells, which express melatonin receptors, were greatly enhanced in response to fracture stress, but this enhancement was blocked by melatonin treatment. Moreover, inhibition of Erk signaling phenocopied the effects of melatonin treatment in the fractured scale. Collectively, these data suggest that the activation of epidermal Erk signaling is required for both osteoblast and osteoclast differentiation in the early stage of fracture healing, and melatonin suppresses epidermal Erk signaling, leading to impaired fracture healing.

A CRISPR/Cas9-mediated gene knockout system in Aspergillus luchuensis mut. kawachii.

We developed an approach to genome editing of the white koji fungus, Aspergillus luchuensis mut. kawachii using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system. Co-transformation of AMA1-based Cas9 and gRNA expression plasmids achieved efficient gene knockout in A. kawachii. The plasmids were easily lost when selective pressure was removed, allowing for successive rounds of genome editing.

Anteroposterior molecular registries in ectoderm of the echinus rudiment.

BACKGROUND: Echinoderms and hemichordates are sister taxa that both have larvae with tripartite coeloms. Hemichordates inherit the coelom plan and ectoderm from larvae, whereas echinoderms form the adult rudiment comprising rearranged coeloms and a vestibule that then develops into adult oral ectoderm. Molecular networks that control patterns of the ectoderm and the central nervous system along the anteroposterior (AP) axis are highly conserved between hemichordates and chordates, respectively. In echinoderms, however, little is known about the AP registry in the ectoderm. RESULTS: We isolated ectodermal AP map genes from the sand dollar Peronella japonica and examined their expression. Comparative expression analyses showed that (1) P. japonica orthologs of hemichordate anterior markers are expressed in the larval apical plate, which degenerates during metamorphosis; (2) P. japonica orthologs of the medial markers are expressed in the ambulacral ectoderm of the rudiment; and (3) few P. japonica orthologs of the posterior markers are expressed in ectoderm. CONCLUSIONS: We suggest that echinoids only inherit the ambulacral ectoderm from a common ambulacrarian ancestor, which largely corresponds to the collar ectoderm in hemichordates. The ectodermal AP registry provides insights into the AP axis and evolutionary processes of echinoderms from a common ambulacrarian ancestor. Developmental Dynamics 247:1297-1307, 2018. © 2018 Wiley Periodicals, Inc.

Larval mesenchyme cell specification in the primitive echinoid occurs independently of the double-negative gate.

Echinoids (sea urchins) are divided into two major groups - cidaroids (a 'primitive' group) and euechinoids (a 'derived' group). The cidaroids are a promising model species for understanding the ancestral developmental mechanisms in echinoids, but little is known about the molecular mechanisms of cidaroid development. In euechinoids, skeletogenic mesenchyme cell specification is regulated by the double-negative gate (DNG), in which hesC represses the transcription of the downstream mesenchyme specification genes (alx1, tbr and ets1), thereby defining the prospective mesenchyme region. To estimate the ancestral mechanism of larval mesenchyme cell specification in echinoids, the expression patterns and roles of mesenchyme specification genes in the cidaroid Prionocidaris baculosa were examined. The present study reveals that the expression pattern and function of hesC in P. baculosa were inconsistent with the DNG model, suggesting that the euechinoid-type DNG is not utilized during cidaroid mesenchyme specification. In contrast with hesC, the expression patterns and functions of alx1, tbr and ets1 were similar between P. baculosa and euechinoids. Based on these results, we propose that the roles of alx1, tbr and ets1 in mesenchyme specification were established in the common ancestor of echinoids, and that the DNG system was acquired in the euechinoid lineage after divergence from the cidaroid ancestor. The evolutionary timing of the establishment of the DNG suggests that the DNG was originally related to micromere and/or primary mesenchyme cell formation but not to skeletogenic cell differentiation.

Hox expression in the direct-type developing sand dollar Peronella japonica.

BACKGROUND: Echinoderms are a curious group of deuterostomes that forms a clade with hemichordates but has a pentameral body plan. Hox complex plays a pivotal role in axial patterning in bilaterians and often occurs in a cluster on the chromosome. In contrast to hemichordates with an organized Hox cluster, the sea urchin Strongylocentrotus purpuratus has a Hox cluster with an atypical organization. However, the current data on hox expression in sea urchin rudiments are fragmentary. RESULTS: We report a comprehensive examination of hox expression in a sand dollar echinoid. Nine hox genes are expressed in the adult rudiment, which are classified into two groups, but hox11/13b belongs to both: one with linear expression in the coelomic mesoderm and another with radial expression around the adult mouth. The linear genes may endow the coelom/mesentery with axial information to direct postmetamorphic transformation of the digestive tract, whereas the radial genes developmentally correlate with the morphological novelties of echinoderms and/or sea urchins. Recruitment of the radial genes except hox11/13b appears to be accompanied by the loss of ancestral/axial roles. CONCLUSIONS: This in toto co-option of the hox genes provides insight into the molecular mechanisms underlying the evolution of echinoderms from a bilateral ancestor.

Development of the swimming acorn worm Glandiceps hacksi: similarity to holothuroids.

Spawnings of Glandiceps hacksi (Hemichordata: Enteropneusta) were stimulated in the laboratory by a brief increase in temperature, and the development from fertilization through metamorphosis is described for the first time for a member of the family Spengelidae. When fertilized, the spawned female gametes, which are primary oocytes, rapidly raise a fertilization membrane and undergo two maturation divisions. Holoblastic, radial cleavage produces a blastula; a gastrula then forms by invagination from the vegetal pole, and the blastopore closes soon thereafter. In previously described enteropneust embryos, the archenteron buds off the protocoel before the latter connects to the exterior via the proboscis pore. By contrast, in G. hacksi the archenteron precociously connects with the exterior before the protocoel forms. Soon thereafter, the embryo becomes uniformly ciliated and then hatches from the fertilization envelope at approximately 32 h (15°C culture temperature). At day 3 of development, the protocoel separates from the gut, which establishes a mouth opening to the exterior; by this time, the gut has differentiated into an esophagus, a stomach, and an intestine that opens posteriorly as an anus. The larva grows to form a tornaria with distinctive pigment patches along its ciliary bands.

Morphological and metabolomics profiling of intraspecific Arabidopsis hybrids in relation to biomass heterosis.

Heterosis contributes greatly to the worldwide agricultural yield. However, the molecular mechanism underlying heterosis remains unclear. This study took advantage of Arabidopsis intraspecific hybrids to identify heterosis-related metabolites. Forty-six intraspecific hybrids were used to examine parental effects on seed area and germination time. The degree of heterosis was evaluated based on biomass: combinations showing high heterosis of F1 hybrids exhibited a biomass increase from 6.1 to 44% over the better parent value (BPV), whereas that of the low- and no-heterosis hybrids ranged from - 19.8 to 9.8% over the BPV. Metabolomics analyses of F1 hybrids with high heterosis and those with low one suggested that changes in TCA cycle intermediates are key factors that control growth. Notably, higher fumarate/malate ratios were observed in the high heterosis F1 hybrids, suggesting they provide metabolic support associated with the increased biomass. These hybrids may produce more energy-intensive biomass by speeding up the efficiency of TCA fluxes. However, the expression levels of TCA-process-related genes in F1 hybrids were not associated with the intensity of heterosis, suggesting that the post-transcriptional or post-translational regulation of these genes may affect the productivity of the intermediates in the TCA cycle.

Par6 regulates skeletogenesis and gut differentiation in sea urchin larvae.

Partitioning-defective (par) genes were originally identified as genes that are essential for the asymmetric division of the Caenorhabditis elegans zygote. Studies have since revealed that the gene products are part of an evolutionarily conserved PAR-atypical protein kinase C system involved in cell polarity in various biological contexts. In this study, we analyzed the function of par6 during sea urchin morphogenesis by morpholino-mediated knockdown and by manipulation swapping of the primary mesenchyme cells (PMCs). Loss of Par6 resulted in defects in skeletogenesis and gut differentiation in larvae. Phenotypic analyses of chimeras constructed by PMC swapping showed that Par6 in non-PMCs is required for differentiation of archenteron into functional gut. In contrast, Par6 in both PMCs and ectodermal cells cooperatively regulates skeletogenesis. We suggest that Par6 in PMCs plays an immediate role in the deposition of biomineral in the syncytial cable, whereas Par6 in ectoderm may stabilize skeletal rods via an unknown signal(s).

Unusual coelom formation in the direct-type developing sand dollar Peronella japonica.

Peronella japonica is a sand dollar with a zygote that develops into an abbreviated pluteus but then metamorphoses on day three. The adult rudiment formation is unique; it uses a median position of the hydrocoel and a stomodeum-like invagination of vestibule that covers the dorsal side of the hydrocoel. However, the developmental processes underlying coelom formation remain unclear. In this study, we examined this process by reconstructing three-dimensional images from serial sections of larvae. We show that the left coelom developed by both schizocoely and enterocoely from the archenteron tip, whereas the hydrocoel and right coelom formed by enterocoely from the archenteron. This coelom formation arranged the coelomic compartments directly along the adult oral-aboral axis by skipping the initial bilateral phases. Furthermore, our data indicate P. japonica retains ancestral asymmetry along the left-right axis in the location of the adult rudiment.

Unique histopathological features of graft biopsies with liver function abnormalities in living donor liver transplant patients receiving basiliximab induction therapy.

Induction with basiliximab (BXM) has been confirmed as an effective treatment regimen for prophylaxis of acute cellular rejection (ACR). From 1991 to 2008, 116 living donor liver transplantations (LDLTs) were performed. Among these, 50 were included in this study. We compared calcineurin inhibitor plus steroid treatment without BXM (n = 14, control group) and with BXM (n = 36, BXM group). Although the rates of biopsied patients with abnormal serum biochemical tests (SBTs) were similar in the control (10/14, 71.4%) and BXM (21/36, 58.3%) groups, ACR was diagnosed in 9/10 (90.0%) patients in the control group compared with 4/21 (19.0%) patients in the BXM group. In accordance with the histopathological diagnosis, there was a significant difference in the ratios of peripheral CD4(+) CD25(+) T cells at five wk after LDLT between patients with and without ACR in the BXM group. Next, we divided the 32 patients without ACR in the BXM group into two groups: biopsied patients with abnormal SBTs and non-biopsied patients. The donor age of the biopsied patients was significantly higher than that of the non-biopsied patients. Induction with BXM reduced the incidence of ACR, and unique pathological phenomena responsible for graft dysfunction after LDLT with an increased incidence of abnormal SBTs were observed.

Conserved early expression patterns of micromere specification genes in two echinoid species belonging to the orders clypeasteroida and echinoida.

The micromere gene regulatory network (GRN) has been extensively examined using sea urchins belonging to the order Echinoida. To examine whether the network of Echinoida species is conserved in Scaphechinus mirabilis, an irregular echinoid of the order Clypeasteroida, the genes micro1, hesC, alx1, ets1, and delta were isolated from S. mirabilis and their expression patterns were compared with those from Hemicentrotus pulcherrimus, a species belonging to the order Echinoida. Data from this study suggest that the early GRN architecture had been largely established in a common ancestor of these two species. On the other hand, we found vegetal shifts in expression domains of some GRN members in H. pulcherrimus embryos compared to S. mirabilis embryos.

Synthesis and formation mechanism of hydrogenated boron clusters B(12)H(n) with controlled hydrogen content.

We present the formation of hydrogen-content-controlled B(12)H(n) (+) clusters through the decomposition and ion-molecule reactions of the decaborane (B(10)H(14)) and diborane (B(2)H(6)) molecules in an external quadrupole static attraction ion trap. The hydrogen- and boron-contents of the B(10-y)H(x) (+) cluster are controlled by charge transfer from ambient gas ions. In the process of ionization, a certain number of hydrogen and boron atoms are detached from decaborane ions by the energy caused by charge transfer. The energy caused by the ion-molecule reactions also induces H atom detachment. Ambient gas of Ar leads to the selective generation of B(10)H(6) (+). The B(10)H(6) (+) clusters react with B(2)H(6) molecules, resulting in the selective formation of B(12)H(8) (+) clusters. Ambient gas of Ne (He) leads to the generation of B(10-y)H(x) (+) clusters with x=4-10 and y=0-1 (with x=2-10 and y=0-2), resulting in the formation of B(12)H(n) (+) clusters with n=4-8 (n=2,4-8). The introduction of ambient gas also increases the production of clusters. PBE0/6-311+G(d)//B3LYP/6-31G(d)-level density functional theory calculations are conducted to investigate the structure and the mechanism of formation of B(10-y)H(x) (+) and B(12)H(n) (+) clusters.

[A case of triple malignant tumors consisting of esophagus, stomach and malignant lymphoma with a histopathological feature of collision between gastric cancer and malignant lymphoma--a case report].

We report a rare case of a collision between a gastric cancer and a malignant lymphoma with a wide systemic metastasis, combined with esophagus cancer, stomach cancer and malignant lymphoma. A 73-year-old man complained of gross hematuria and swelling of the right testis. Magnetic resonance imaging (MRI) revealed that both testes were swollen with unequal contrast and there were numerous tumors in the retroperitoneal space and pelvis. He was diagnosed with malignant diffuse large B cell lymphoma by immunostaining from the extirpated right testis. He received six cycles of R-CHOP therapy. After the second cycle, partial remission was recognized, but the tumors spread again by the fourth cycle. Thereafter, we performed MTX-HOPE therapy as a salvage therapy for four cycles. During this chemotherapy, he felt epigastralgia; esophagus cancer (squamous cell carcinoma) and stomach cancer (highly-differentiated adenocarcinoma) were found by upper endoscopy. However, the gastrointestinal cancer was inoperable, since the malignant lymphoma was progressive. His general status had been exacerbated, and he died about one year after he was diagnosed with malignant lymphoma. Pathological examination revealed that the adenocarcinoma had partly collided with the malignant lymphoma.

Uptake of osteoblast-derived extracellular vesicles promotes the differentiation of osteoclasts in the zebrafish scale.

Differentiation of osteoclasts (OCs) from hematopoietic cells requires cellular interaction with osteoblasts (OBs). Due to the difficulty of live-imaging in the bone, however, the cellular and molecular mechanisms underlying intercellular communication involved in OC differentiation are still elusive. Here, we develop a fracture healing model using the scale of trap:GFP; osterix:mCherry transgenic zebrafish to visualize the interaction between OCs and OBs. Transplantation assays followed by flow cytometric analysis reveal that most trap:GFPhigh OCs in the fractured scale are detected in the osterix:mCherry+ fraction because of uptake of OB-derived extracellular vesicles (EVs). In vivo live-imaging shows that immature OCs actively interact with osterix:mCherry+ OBs and engulf EVs prior to convergence at the fracture site. In vitro cell culture assays show that OB-derived EVs promote OC differentiation via Rankl signaling. Collectively, these data suggest that EV-mediated intercellular communication with OBs plays an important role in the differentiation of OCs in bone tissue.

Krüppel-like is required for nonskeletogenic mesoderm specification in the sea urchin embryo.

The canonical Wnt pathway plays a central role in specifying vegetal cell fate in sea urchin embryos. SpKrl has been cloned as a direct target of nuclear beta-catenin. Using Hemicentrotus pulcherrimus embryos, here we show that HpKrl controls the specification of secondary mesenchyme cells (SMCs) through both cell-autonomous and non-autonomous means. Like SpKrl, HpKrl was activated in both micromere and macromere progenies. To examine the functions of HpKrl in each blastomere, we constructed chimeric embryos composed of blastomeres from control and morpholino-mediated HpKrl-knockdown embryos and analyzed the phenotypes of the chimeras. Micromere-swapping experiments showed that HpKrl is not involved in micromere specification, while micromere-deprivation assays indicated that macromeres require HpKrl for cell-autonomous specification. Transplantation of normal micromeres into a micromere-less host with morpholino revealed that macromeres are able to receive at least some micromere signals regardless of HpKrl function. From these observations, we propose that two distinct pathways of endomesoderm formation exist in macromeres, a Krl-dependent pathway and a Krl-independent pathway. The Krl-independent pathway may correspond to the Delta/Notch signaling pathway via GataE and Gcm. We suggest that Krl may be a downstream component of nuclear beta-catenin required by macromeres for formation of more vegetal tissues, not as a member of the Delta/Notch pathway, but as a parallel effector of the signaling (Krl-dependent pathway).

The Hox8 of the hemichordate Balanoglossus misakiensis.

Deuterostomes comprise a monophyletic group of animals that include chordates, xenoturbellids, and the Ambulacraria, which consists of echinoderms and hemichordates. The ancestral chordate probably had 14 Hox genes aligned linearly along the chromosome, with the posterior six genes showing an independent duplication compared to protostomes. In contrast, ambulacrarians are characterized by a duplication of the posterior Hox genes, resulting in three genes known as Hox11/13a, Hox11/13b, and Hox11/13c. Here, we isolated 12 Hox genes from the hemichordate Balanoglossus misakiensis and found an extra Hox gene that has not been reported in hemichordates. The extra B. misakiensis gene was suggested to be Hox8 from paralog-characteristic residues in its hexapepetide motif and homeodomain and a comparison with Strongylocentrotus purpuratus Hox genes. Our data suggest that the ancestor of echinoderms and hemichordates may have had a full complement of 12 Hox genes.

Expression patterns of three Par-related genes in sea urchin embryos.

Partitioning-defective (Par) genes were originally identified in Caenorhabditis elegans and are involved in asymmetric divisions of the egg. Recently, the expression and function of Par orthologs have been elucidated in deuterostomes, including vertebrates. In this study, we isolated three Par-related genes, Par-1, Par-6, and atypical protein kinase C (aPKC), from the sea urchin Hemicentrotus pulcherrimus and examined their temporal and spatial expression patterns during embryogenesis up to the pluteus stage. All three transcripts existed maternally in eggs and were uniformly expressed in cleavage-stage embryos. From the blastula to early gastrula stages, HpPar-1 expression was transiently restricted to the vegetal plate, including the primary mesenchyme cells (PMCs); this transient reduction was followed by uniform expression. HpPar-6 was expressed uniformly throughout development. In contrast, HpaPKC expression changed dramatically during development. At the blastula stage, HpaPKC expression was restricted to the vegetal region, including PMCs and the vegetal plate. During gastrulation, expression was maintained in PMCs and the archenteron tip, but expression declined at the late gastrula stage. From the prism stage, two cell types started to express HpaPKC: ectoderm cells interspersed in the ciliary band and skeletogenic cells at the posterior end of the larva. At the pluteus stage, the stomach began to express HpaPKC, in addition to the interspersed ciliary band and skeletogenic cells.

Development of ciliary bands in larvae of the living isocrinid sea lily Metacrinus rotundus.

Embryos and larvae of an isocrinid sea lily, Metacrinus rotundus, are described by scanning electron microscopy. Around hatching (35 h after fertilization), the outer surface of the gastrula becomes ubiquitously covered with short cilia. At 40 h, the hatched swimming embryo develops a cilia-free zone of ectoderm on the ventral side. By 3 days, the very early dipleurula larva develops a cilia-free zone ventrally, densely ciliated regions laterally, and a sparsely ciliated region dorsally. At this stage, the posterior and anterior ciliary bands first appear: the former runs along a low ridge separating the densely from the sparsely ciliated epidermal regions, while the latter is visible, at first discontinuously, along the boundary between the densely ciliated lateral regions and the cilia-free ventral zone. In the late dipleurula larva (5 days after fertilization), the anterior and posterior loops of ciliary bands are well defined. The transition from the dipleurula to the semidoliolaria larva occurs at 6 days as the posterior loop becomes rearranged to form incompletely circumferential ciliary bands. The larva becomes competent to settle at this stage. The arrangement of the ciliary bands on the semidoliolaria is maintained during the second week of development, while the larva retains its competence to settle. The larval ciliary patterns described here are compared with those of stalkless crinoids and eleutherozoan echinoderms. The closest morphological similarities are between M. rotundus and the basal eleutherozoan class Asteroidea.