HyAlx, an aristaless-related gene, is involved in tentacle formation in hydra

Development ◽  
2000 ◽  
Vol 127 (22) ◽  
pp. 4743-4752 ◽  
Author(s):  
K.M. Smith ◽  
L. Gee ◽  
H.R. Bode
Keyword(s):  
Expression Patterns ◽  
Reaction Diffusion ◽  
The Body ◽  
Related Gene ◽  
Axial Patterning ◽  
Bud Formation ◽  
Isolation And Characterization ◽  
Reaction Diffusion Model ◽  
Head Regeneration

Developmental gradients are known to play important roles in axial patterning in hydra. Current efforts are directed toward elucidating the molecular basis of these gradients. We report the isolation and characterization of HyAlx, an aristaless-related gene in hydra. The expression patterns of the gene in adult hydra, as well as during bud formation, head regeneration and the formation of ectopic head structures along the body column, indicate the gene plays a role in the specification of tissue for tentacle formation. The use of RNAi provides more direct evidence for this conclusion. The different patterns of HyAlx expression during head regeneration and bud formation also provide support for a recent version of a reaction-diffusion model for axial patterning in hydra.

Fragile skeletal muscle attachments in dystrophic mutants of Caenorhabditis elegans: isolation and characterization of the mua genes

Development ◽  
2000 ◽  
Vol 127 (6) ◽  
pp. 1197-1207 ◽  
Author(s):  
J.D. Plenefisch ◽  
X. Zhu ◽  
E.M. Hedgecock
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Wall ◽  
Local Strain ◽  
Muscle Differentiation ◽  
The Body ◽  
Tissue Separation ◽  
New Genes ◽  
Isolation And Characterization ◽  
Skin Fragility

Over 30 Caenorhabditis elegans mutants were identified with normal muscle differentiation and initial locomotion followed by catastrophic detachment of skeletal muscles from the body wall. Reducing the strength of muscle contraction in these mutants with a myosin gene mutation suppresses muscle detachment. These dystrophic mutants identify a novel class of genes required for growth and maintenance of functional muscle attachments, not exceptional alleles of genes required for muscle differentiation and contractility. Nine new genes, named mua, and two previously published loci, unc-23 and vab-10, cause fragile musscle attachments. The primary sites of muscle detachment, including the plane of tissue separation, are characteristic for each gene. We suggest these genes identify feedback mechanisms whereby local strain regulates the extent of myofibril contraction and the placement of new muscle attachments in functioning muscles. Finally, we draw some comparisons to vertebrate skin fragility diseases and muscular dystrophies.

scholarly journals Isolation and characterization of a low-molecular-weight substance activating head and bud formation in hydra

Development ◽  
1973 ◽  
Vol 29 (1) ◽  
pp. 27-38
Author(s):  
H. Chica Schaller
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Bud Formation ◽  
Isolation And Characterization ◽  
Crude Extracts ◽  
Head Formation ◽  
Weight Substance

From crude extracts of hydra, a substance activating head formation was isolated and enriched at least 100000-fold. The molecular weight was determined to be approximately 900. Sensitivity against proteases suggests that it is a peptide. The substance acts at a concentration equivalent to the extract of 1 hydra per ml or at a concentration of less than 10 10M. In its highly purified form the substance activates head and bud formation.

scholarly journals Correspondences between parameters in a reaction-diffusion model and connexin functions during zebrafish stripe formation

2021 ◽  
Author(s):  
Akiko Nakamasu
Keyword(s):  
Molecular Mechanisms ◽  
Reaction Diffusion ◽  
The Body ◽  
Pigment Cells ◽  
Turing Pattern ◽  
Reaction Diffusion Model ◽  
Spatial Periodicity ◽  
Pattern Formations ◽  
Mathematical Analyses ◽  
Spotted Pattern

Abstract Different diffusivities among interacting substances actualize the potential instability of a system. When these elicited instabilities manifested as forms of spatial periodicity, they are called Turing patterns. Simulations using general reaction-diffusion (RD) models have demonstrated that pigment patterns on the body trunk of growing fish follow a Turing pattern. Laser ablation experiments performed on zebrafish revealed apparent interactions among pigment cells, which allowed for a three-components RD model to be derived. However, the underlying molecular mechanisms responsible for Turing pattern formation in this system had been remained unknown. A zebrafish mutant with a spotted pattern was found to have a defect in Connexin41.8 (Cx41.8) which, together with Cx39.4, exists in pigment cells and controls pattern formations. Here, molecular-level evidence derived from connexin analyses was linked to the interactions among pigment cells described in previous RD modeling. Channels on pigment cells were generalized as “gates,” and the effects of respective gates were deduced. The model used partial differential equations (PDEs) to enable numerical and mathematical analyses of characteristics observed in the experiments. Furthermore, the improved PDE model included nonlinear reaction terms, enabled the consideration of the behavior of components.

Isolation and characterization of mRNAs accumulated during in-vitro flower bud formation

Planta ◽  
1994 ◽  
Vol 195 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Anton J. M. Peeters ◽  
Marcel Proveniers ◽  
Angela van Hoek ◽  
Max Schreuder ◽  
Will Gerards ◽  
...  
Keyword(s):  
Flower Bud ◽  
Bud Formation ◽  
Isolation And Characterization ◽  
Flower Bud Formation

Isolation and characterization of a novel mouse erythroid differentiation-denucleation related gene (MEDDF)

1999 ◽  
Vol 44 (15) ◽  
pp. 1375-1379
Author(s):  
Zhengyan Zhang ◽  
Shiguang Liu ◽  
Jingbo Zhang ◽  
Shepu Xue
Keyword(s):  
Erythroid Differentiation ◽  
Related Gene ◽  
Isolation And Characterization

scholarly journals SULFATION PATHWAYS: Expression of SULT2A1, SULT2B1 and HSD3B1 in the porcine testis and epididymis

2018 ◽  
Vol 61 (2) ◽  
pp. M41-M55 ◽  
Author(s):  
B Zimmer ◽  
L Tenbusch ◽  
M C Klymiuk ◽  
Y Dezhkam ◽  
G Schuler
Keyword(s):  
Western Blot ◽  
Real Time ◽  
Leydig Cells ◽  
Expression Patterns ◽  
The Body ◽  
High Expression ◽  
Activity Measurements ◽  
Tissue Homogenates ◽  
Porcine Testis

In the porcine testis, in addition to estrogen sulfates, the formation of numerous sulfonated neutral hydroxysteroids has been observed. However, their functions and the underlying synthetic pathways are still widely unclear. To obtain further information on their formation in postpubertal boars, the expression of sulfotransferases considered relevant for neutral hydroxysteroids (SULT2A1, SULT2B1) was investigated in the testis and defined segments of the epididymis applying real-time RT-qPCR, Western blot and immunohistochemistry (IHC). Sulfotransferase activities were assessed in tissue homogenates or cytosolic preparations applying dehydroepiandrosterone and pregnenolone as substrates. A high SULT2A1 expression was confirmed in the testis and localized in Leydig cells by IHC. In the epididymis, SULT2A1 expression was virtually confined to the body. SULT2B1 expression was absent or low in the testis but increased significantly along the epididymis. Immunohistochemical observations indicate that both enzymes are secreted into the ductal lumen via an apocrine mechanism. The results from the characterization of expression patterns and activity measurements suggest that SULT2A1 is the prevailing enzyme for the sulfonation of hydroxysteroids in the testis, whereas SULT2B1 may catalyze the formation of sterol sulfates in the epididymis. In order to obtain information on the overall steroidogenic capacity of the porcine epididymis, the expression of important steroidogenic enzymes (CYP11A1, CYP17A1, CYP19, HSD3B1, HSD17B3, SRD5A2) was monitored in the defined epididymal segments applying real-time RT-qPCR. Surprisingly, in addition to a high expression of SRD5A2 in the epididymal head, a substantial expression of HSD3B1 was detected, which increased along the organ.

Isolation and characterization of curcin genes with distinct expression patterns in leaves and seeds of Jatropha curcas L.

Plant Gene ◽  
2017 ◽  
Vol 9 ◽  
pp. 34-44 ◽  
Author(s):  
Lifang Wu ◽  
Mei Ling Goh ◽  
Dongsheng Tian ◽  
Keyu Gu ◽  
Yan Hong ◽  
...  
Keyword(s):  
Jatropha Curcas ◽  
Expression Patterns ◽  
Jatropha Curcas L ◽  
Isolation And Characterization

Characterization of the head organizer in hydra

Development ◽  
2002 ◽  
Vol 129 (4) ◽  
pp. 875-884 ◽  
Author(s):  
Mariya Broun ◽  
Hans R. Bode
Keyword(s):  
Organizer Region ◽  
Apical Part ◽  
The Body ◽  
Central Process ◽  
Axial Patterning ◽  
Secondary Axis ◽  
Head Formation ◽  
Body Column ◽  
Self Organizing

A central process in the maintenance of axial patterning in the adult hydra is the head activation gradient, i.e. the potential to form a secondary axis, which is maximal in the head and is graded down the body column. Earlier evidence suggested that this gradient was based on a single parameter. Using transplantation experiments, we provide evidence that the hypostome, the apical part of the head, has the characteristics of an organizer in that it has the capacity to induce host tissue to form most of the second axis. By contrast, tissue of the body column has a self-organizing capacity, but not an inductive capacity. That the inductive capacity is confined to the hypostome is supported by experiments involving a hypostome-contact graft. The hypostome, but not the body column, transmits a signal(s) leading to the formation of a second axis. In addition, variations of the transplantation grafts and hypostome-contact grafts provide evidence for several characteristics of the organizer. The inductive capacity of the head and the self-organizing capacity of the body column are based on different pathways. Head inhibition, yya signal produced in the head and transmitted to the body column to prevent head formation, represses the effect of the inducing signal by interfering with formation of the hypostome/organizer. These results indicate that the organizer characteristics of the hypostome of an adult hydra are similar to those of the organizer region of vertebrate embryos. They also indicate that the Gierer-Meinhardt model provides a reasonable framework for the mechanisms that underlie the organizer and its activities. In addition, the results suggest that a region of an embryo or adult with the characteristics of an organizer arose early in metazoan evolution.

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