scholarly journals Zic1 advances epaxial myotome morphogenesis to cover the neural tube via Wnt11r

2021 ◽  
Author(s):  
Ann Kathrin Heilig ◽  
Ryohei Nakamura ◽  
Atsuko Shimada ◽  
Yuka Hashimoto ◽  
Yuta Nakamura ◽  
...  
Keyword(s):  
Neural Tube ◽  
Proliferative Activity ◽  
Cell Communication ◽  
Wild Type ◽  
Chip Sequencing ◽  
Axial Muscles ◽  
Incomplete Coverage ◽  
High Proliferative Activity ◽  
Matrix Organization ◽  
Epaxial Muscles

The dorsal axial muscles, or epaxial muscles, are a fundamental structure covering the spinal cord and vertebrae, as well as mobilizing the vertebrate trunk. To date, mechanisms underlying the morphogenetic process shaping the epaxial myotome are largely unknown. To address this, we used the medaka zic1/zic4-enhancer mutant Double anal fin (Da), which exhibits ventralized dorsal trunk structures resulting in impaired epaxial myotome morphology and incomplete coverage over the neural tube. In wild type, dorsal dermomyotome (DM) cells, progenitors of myotomal cells, reduce their proliferative activity after somitogenesis and subsequently form unique large protrusions extending dorsally, potentially guiding the epaxial myotome dorsally. In Da, by contrast, DM cells maintain the high proliferative activity and form mainly small protrusions. By combining RNA- and ChIP-sequencing analyses, we revealed direct targets of Zic1 which are specifically expressed in dorsal somites and involved in various aspects of development, such as cell migration, extracellular matrix organization and cell-cell communication. Among these, we identified wnt11r as a crucial factor regulating both cell proliferation and protrusive activity of DM cells. We propose that the dorsal movement of the epaxial myotome is guided by DM cells and that Zic1 empowers this activity via Wnt11r to achieve the neural tube coverage.

scholarly journals N-3-Hydroxy Dodecanoyl-DL-homoserine Lactone (OH-dDHL) Triggers Apoptosis of Bone Marrow-Derived Macrophages through the ER- and Mitochondria-Mediated Pathways

2021 ◽  
Vol 22 (14) ◽  
pp. 7565
Author(s):  
Kyungho Woo ◽  
Dong Ho Kim ◽  
Man Hwan Oh ◽  
Ho Sung Park ◽  
Chul Hee Choi
Keyword(s):  
Bone Marrow ◽  
Quorum Sensing ◽  
Deletion Mutant ◽  
Transmembrane Protein ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Host Responses ◽  
Wild Type ◽  
Mutant Strains

Quorum sensing of Acinetobacter nosocomialis for cell-to-cell communication produces N-3-hydroxy dodecanoyl-DL-homoserine lactone (OH-dDHL) by an AnoR/I two-component system. However, OH-dDHL-driven apoptotic mechanisms in hosts have not been clearly defined. Here, we investigated the induction of apoptosis signaling pathways in bone marrow-derived macrophages treated with synthetic OH-dDHL. Moreover, the quorum-sensing system for virulence regulation was evaluated in vivo using wild-type and anoI-deletion mutant strains. OH-dDHL decreased the viability of macrophage and epithelial cells in dose- and time-dependent manners. OH-dDHL induced Ca2+ efflux and caspase-12 activation by ER stress transmembrane protein (IRE1 and ATF6a p50) aggregation and induced mitochondrial dysfunction through reactive oxygen species (ROS) production, which caused cytochrome c to leak. Pretreatment with a pan-caspase inhibitor reduced caspase-3, -8, and -9, which were activated by OH-dDHL. Pro-inflammatory cytokine and paraoxonase-2 (PON2) gene expression were increased by OH-dDHL. We showed that the anoI-deletion mutant strains have less intracellular invasion compared to the wild-type strain, and their virulence, such as colonization and dissemination, was decreased in vivo. Consequently, these findings revealed that OH-dDHL, as a virulence factor, contributes to bacterial infection and survival as well as the modification of host responses in the early stages of infection.

All-or-none craniorachischisis in Loop-tail mutant mouse chimeras

Development ◽  
1990 ◽  
Vol 110 (1) ◽  
pp. 229-237 ◽  
Author(s):  
T.S. Musci ◽  
R.J. Mullen
Keyword(s):  
Neural Tube ◽  
Mutant Gene ◽  
Mutant Phenotype ◽  
Progeny Testing ◽  
Wild Type ◽  
Glucose Phosphate ◽  
Threshold Mechanism ◽  
Mutant Cells ◽  
Intermediate Expression ◽  
Gross Examination

Mouse embryos homozygous for the mutant gene Loop-tail (Lp) are characterized by craniorachischisis, an open neural tube extending from the midbrain to the tail. In the present study, experimental chimeric mice containing mixtures of genetically mutant (from Lp/+ × Lp/+ matings) and genetically normal cells were produced. Our aim was to determine whether a ‘rescue,’ phenotypic gradient, or intermediate expression (i.e. alternating areas of open and closed neural tube) would be observed in these chimeras. We report our analyses of Loop-tail mutant chimeras (n = 82) by gross examination, progeny testing and quantitative analysis of glucose phosphate isomerase (GPI) isozyme levels. An all-or-none craniorachischisis in Loop-tail mutant chimeras was observed. Two multicolored adult chimeras, without any gross evidence of a neural tube defect, were shown to be homozygous Loop-tail chimeras (Lp/Lp in equilibrium +/+) by progeny testing. These results indicate that the normal phenotype can be expressed in the presence of mutant cells. Conversely, six neonates with craniorachischisis were shown to be chimeras by GPI analyses. These results show that the full mutant phenotype can be expressed even when one-third to one-half of the cells are genotypically wild-type. This study did not determine which tissue is primarily responsible for the defective neurulation in this mutant, but suggests that a ‘threshold’ mechanism underlies the Loop-tail mutant phenotype. In some chimeras that threshold is not reached and the neural tube remains open, whereas in other chimeras the threshold is reached and the neural tube closes completely.

Cell-autonomous shift from axial to paraxial mesodermal development in zebrafish floating head mutants

Development ◽  
1995 ◽  
Vol 121 (12) ◽  
pp. 4257-4264 ◽  
Author(s):  
M.E. Halpern ◽  
C. Thisse ◽  
R.K. Ho ◽  
B. Thisse ◽  
B. Riggleman ◽  
...  
Keyword(s):  
Neural Tube ◽  
Single Cells ◽  
Floor Plate ◽  
Paraxial Mesoderm ◽  
Wild Type ◽  
Genetic Mosaics ◽  
Essential Step ◽  
Ventral Neural Tube ◽  
Mesodermal Development

Zebrafish floating head mutant embryos lack notochord and develop somitic muscle in its place. This may result from incorrect specification of the notochord domain at gastrulation, or from respecification of notochord progenitors to form muscle. In genetic mosaics, floating head acts cell autonomously. Transplanted wild-type cells differentiate into notochord in mutant hosts; however, cells from floating head mutant donors produce muscle rather than notochord in wild-type hosts. Consistent with respecification, markers of axial mesoderm are initially expressed in floating head mutant gastrulas, but expression does not persist. Axial cells also inappropriately express markers of paraxial mesoderm. Thus, single cells in the mutant midline transiently co-express genes that are normally specific to either axial or paraxial mesoderm. Since floating head mutants produce some floor plate in the ventral neural tube, midline mesoderm may also retain early signaling capabilities. Our results suggest that wild-type floating head provides an essential step in maintaining, rather than initiating, development of notochord-forming axial mesoderm.

scholarly journals Two groups of Arabidopsis receptor kinases preferentially regulate the growth of intraspecies pollen tubes in the female reproductive tract

2020 ◽  
Author(s):  
Hyun Kyung Lee ◽  
Daphne R. Goring
Keyword(s):  
Pollen Tube ◽  
Reproductive Tract ◽  
Cell Communication ◽  
Pollen Grains ◽  
Pollen Tubes ◽  
Female Reproductive Tract ◽  
Wild Type ◽  
Knockout Mutant ◽  
Receptor Kinases ◽  
Compatible Pollen

SummaryIn flowering plants, continuous cell-cell communication between the compatible male pollen grain/growing pollen tube and the female pistil is required for successful sexual reproduction. In Arabidopsis thaliana, the later stages of this dialogue are mediated by several peptide ligands and receptor kinases that guide pollen tubes to the ovules for the release of sperm cells. Despite a detailed understanding of these processes, a key gap remains on the nature of the regulators that function at the earlier stages. Here, we report on two groups of A. thaliana receptor kinases, the LRR-VIII-2 RK subclass and the SERKs, that function in the female reproductive tract to regulate the compatible pollen grains and early pollen tube growth, both essential steps for the downstream processes leading to fertilization. Multiple A. thaliana LRR-VIII-2 RK and SERK knockout mutant combinations were created, and several phenotypes were observed such as reduced wild-type pollen hydration and reduced pollen tube travel distances. As these mutant pistils displayed a wild-type morphology, the observed altered responses of the wild-type pollen are proposed to result from the loss of these receptor kinases leading to an impaired pollen-pistil dialogue at these early stages. Furthermore, using pollen from related Brassicaceae species, we also discovered that these receptor kinases are required in the female reproductive tract to establish a reproductive barrier to interspecies pollen. Thus, we propose that the LRR-VIII-2 RKs and the SERKs play a dual role in the preferential selection and promotion of intraspecies pollen over interspecies pollen.

scholarly journals Flow environment and matrix structure interact to determine spatial competition in Pseudomonas aeruginosa biofilms

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Carey D Nadell ◽  
Deirdre Ricaurte ◽  
Jing Yan ◽  
Knut Drescher ◽  
Bonnie L Bassler
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Spatial Competition ◽  
Evolutionary Stability ◽  
Competitive Dynamics ◽  
Natural Environments ◽  
Wild Type ◽  
Surrounding Environment ◽  
Matrix Organization ◽  
Matrix Production ◽  
Simple Flow

Bacteria often live in biofilms, which are microbial communities surrounded by a secreted extracellular matrix. Here, we demonstrate that hydrodynamic flow and matrix organization interact to shape competitive dynamics in Pseudomonas aeruginosa biofilms. Irrespective of initial frequency, in competition with matrix mutants, wild-type cells always increase in relative abundance in planar microfluidic devices under simple flow regimes. By contrast, in microenvironments with complex, irregular flow profiles – which are common in natural environments – wild-type matrix-producing and isogenic non-producing strains can coexist. This result stems from local obstruction of flow by wild-type matrix producers, which generates regions of near-zero shear that allow matrix mutants to locally accumulate. Our findings connect the evolutionary stability of matrix production with the hydrodynamics and spatial structure of the surrounding environment, providing a potential explanation for the variation in biofilm matrix secretion observed among bacteria in natural environments.

The zebrafish T-box genesno tailandspadetailare required for development of trunk and tail mesoderm and medial floor plate

Development ◽  
2002 ◽  
Vol 129 (14) ◽  
pp. 3311-3323 ◽  
Author(s):  
Sharon L. Amacher ◽  
Bruce W. Draper ◽  
Brian R. Summers ◽  
Charles B. Kimmel
Keyword(s):  
Embryonic Development ◽  
Neural Tube ◽  
Transcriptional Regulators ◽  
Floor Plate ◽  
Wild Type ◽  
T Box ◽  
No Tail ◽  
Ventral Neural Tube ◽  
Plate Formation ◽  
In Cells

T-box genes encode transcriptional regulators that control many aspects of embryonic development. Here, we demonstrate that the mesodermally expressed zebrafish spadetail (spt)/VegT and no tail (ntl)/Brachyury T-box genes are semi-redundantly and cell-autonomously required for formation of all trunk and tail mesoderm. Despite the lack of posterior mesoderm in spt–;ntl– embryos, dorsal-ventral neural tube patterning is relatively normal, with the notable exception that posterior medial floor plate is completely absent. This contrasts sharply with observations in single mutants, as mutations singly in ntl or spt enhance posterior medial floor plate development. We find that ntl function is required to repress medial floor plate and promote notochord fate in cells of the wild-type notochord domain and that spt and ntl together are required non cell-autonomously for medial floor plate formation, suggesting that an inducing signal present in wild-type mesoderm is lacking in spt–;ntl– embryos.

Differential regulation of the chick dorsal thoracic dermal progenitors from the medial dermomyotome

Development ◽  
2002 ◽  
Vol 129 (20) ◽  
pp. 4763-4772 ◽  
Author(s):  
Isabel Olivera-Martinez ◽  
Sylvain Missier ◽  
Sandrine Fraboulet ◽  
Jacques Thélu ◽  
Danielle Dhouailly
Keyword(s):  
Neural Tube ◽  
Central Region ◽  
Differential Regulation ◽  
Dorsal Neural Tube ◽  
The Right ◽  
Dermal Cells ◽  
Epaxial Muscles ◽  
Two Populations ◽  
Axial Organs

The chick dorsal feather-forming dermis originates from the dorsomedial somite and its formation depends primarily on Wnt1 from the dorsal neural tube. We investigate further the origin and specification of dermal progenitors from the medial dermomyotome. This comprises two distinct domains: the dorsomedial lip and a more central region (or intervening zone) that derives from it. We confirm that Wnt1 induces Wnt11 expression in the dorsomedial lip as previously shown, and show using DiI injections that some of these cells, which continue to express Wnt11 migrate under the ectoderm, towards the midline, to form most of the dorsal dermis. Transplantation of left somites to the right side to reverse the mediolateral axis confirms this finding and moreover suggests the presence of an attractive or permissive environment produced by the midline tissues or/and a repellent or inadequate environment by the lateral tissues. By contrast, the dorsolateral dermal cells just delaminate from the surface of the intervening space, which expresses En1. Excision of the axial organs or the ectoderm, and grafting of Wnt1-secreting cells, shows that, although the two populations of dermal progenitors both requires Wnt1 for their survival, the signalling required for their specification differs. Indeed Wnt11 expression relies on dorsal neural tube-derived Wnt1, while En1 expression depends on the presence of the ectoderm. The dorsal feather-forming dermal progenitors thus appear to be differentially regulated by dorsal signals from the neural tube and the ectoderm, and derive directly and indirectly from the dorsomedial lip. As these two dermomyotomal populations are well known to also give rise to epaxial muscles, an isolated domain of the dermomyotome that contains only dermal precursors does not exist and none of the dermomyotomal domains can be considered uniquely as a dermatome.

scholarly journals Fishes can use axial muscles as anchors or motors for powerful suction feeding

2020 ◽  
Vol 223 (18) ◽  
pp. jeb225649 ◽  
Author(s):  
Ariel L. Camp ◽  
Aaron M. Olsen ◽  
L. Patricia Hernandez ◽  
Elizabeth L. Brainerd
Keyword(s):  
Ictalurus Punctatus ◽  
Micropterus Salmoides ◽  
The Body ◽  
Pectoral Girdle ◽  
Suction Feeding ◽  
Axial Muscles ◽  
X Ray Imaging ◽  
Oral Pressure ◽  
Volume Measurements ◽  
Epaxial Muscles

ABSTRACTSome fishes rely on large regions of the dorsal (epaxial) and ventral (hypaxial) body muscles to power suction feeding. Epaxial and hypaxial muscles are known to act as motors, powering rapid mouth expansion by shortening to elevate the neurocranium and retract the pectoral girdle, respectively. However, some species, like catfishes, use little cranial elevation. Are these fishes instead using the epaxial muscles to forcefully anchor the head, and if so, are they limited to lower-power strikes? We used X-ray imaging to measure epaxial and hypaxial length dynamics (fluoromicrometry) and associated skeletal motions (XROMM) during 24 suction feeding strikes from three channel catfish (Ictalurus punctatus). We also estimated the power required for suction feeding from oral pressure and dynamic endocast volume measurements. Cranial elevation relative to the body was small (<5 deg) and the epaxial muscles did not shorten during peak expansion power. In contrast, the hypaxial muscles consistently shortened by 4–8% to rotate the pectoral girdle 6–11 deg relative to the body. Despite only the hypaxial muscles generating power, catfish strikes were similar in power to those of other species, such as largemouth bass (Micropterus salmoides), that use epaxial and hypaxial muscles to power mouth expansion. These results show that the epaxial muscles are not used as motors in catfish, but suggest they position and stabilize the cranium while the hypaxial muscles power mouth expansion ventrally. Thus, axial muscles can serve fundamentally different mechanical roles in generating and controlling cranial motion during suction feeding in fishes.

Cell Kinetics and Tumor-Associated Antigen Expression in Human Mammary Carcinomas

1991 ◽  
Vol 6 (3) ◽  
pp. 159-166 ◽  
Author(s):  
A. Contegiacomo ◽  
R. Mariani Costantini ◽  
R. Muraro ◽  
P. Battista ◽  
C. Valli ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Proliferative Activity ◽  
Antigen Expression ◽  
Breast Carcinomas ◽  
Cellular Kinetics ◽  
Tumor Associated Antigen ◽  
Antigenic Expression ◽  
High Proliferative Activity ◽  
Antigenic Phenotype ◽  
Intense Immunoreactivity

Twenty-six primary breast carcinomas were studied to evaluate cell proliferation as assessed by thymidine labeling index (TLI), and antigenic phenotype, as defined by immunohistochemistry using eight monoclonal antibodies (MAbs) to tumor-associated antigens (TAAs). The majority of tumors had low TLI values. Reactivity to MAbs B72.3, CC49, CC83 (anti TAG 72), COL-12 (anti CEA) and MOv2 (against a tumor-associated mucoprotein) was restricted to < 50% of the tumors studied, while MAbs B1.1 (anti CEA), MBrl and MBr8 (to tumor-associated carbohydrates) reacted with > 50% of the cases. Correlations between expression of TAAs and proliferative activity showed that the tumors could be divided into three groups, two characterized by either high proliferative activity and absence of antigenic expression or low proliferative activity and strong antigenic expression, and the third showing no relation between these two biological features. We defined two antigenic phenotypes associated with specific cellular kinetics: one characterized by negative immunoreaction with MAbs, CC49, CC83 and COL-12 and high proliferative activity; the other characterized by intense immunoreactivity with these antibodies and low proliferative activity. The data suggest that cell proliferation and antigenic phenotype may define biologic subsets of breast carcinomas

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