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.

Cngsc, a homologue of goosecoid, participates in the patterning of the head, and is expressed in the organizer region of Hydra

Development ◽  
1999 ◽  
Vol 126 (23) ◽  
pp. 5245-5254 ◽  
Author(s):  
M. Broun ◽  
S. Sokol ◽  
H.R. Bode
Keyword(s):  
Sensory Neurons ◽  
Organizer Region ◽  
Ventral Side ◽  
Evolutionary Conservation ◽  
The Body ◽  
Secondary Axis ◽  
Head Formation ◽  
Per Se ◽  
Endodermal Cells ◽  
Body Column

We have isolated Cngsc, a hydra homologue of goosecoid gene. The homeodomain of Cngsc is identical to the vertebrate (65-72%) and Drosophila (70%) orthologues. When injected into the ventral side of an early Xenopus embryo, Cngsc induces a partial secondary axis. During head formation, Cngsc expression appears prior to, and directly above, the zone where the tentacles will emerge, but is not observed nearby when the single apical tentacle is formed. This observation indicates that the expression of the gene is not necessary for the formation of a tentacle per se. Rather, it may be involved in defining the border between the hypostome and the tentacle zone. When Cngsc(+) tip of an early bud is grafted into the body column, it induces a secondary axis, while the adjacent Cngsc(−) region has much weaker inductive capacities. Thus, Cngsc is expressed in a tissue that acts as an organizer. Cngsc is also expressed in the sensory neurons of the tip of the hypostome and in the epithelial endodermal cells of the upper part of the body column. The plausible roles of Cngsc in organizer function, head formation and anterior neuron differentiation are similar to roles goosecoid plays in vertebrates and Drosophila. It suggests widespread evolutionary conservation of the function of the gene.

scholarly journals A Wnt-specific astacin proteinase controls head formation in Hydra

2020 ◽  
Author(s):  
Berenice Ziegler ◽  
Irene Yiallouros ◽  
Benjamin Trageser ◽  
Sumit Kumar ◽  
Moritz Mercker ◽  
...  
Keyword(s):  
The Body ◽  
Regulatory Function ◽  
Beta Catenin ◽  
Processing Factor ◽  
Primary Body ◽  
Head Formation ◽  
Signaling Center ◽  
Sirna Knockdown ◽  
Body Column ◽  
Activator Inhibitor

AbstractThe Hydra head organizer acts as a signaling center that initiates and maintains the primary body axis in steady state polyps and during budding or regeneration. Wnt/beta-Catenin signaling functions as a primary cue controlling this process, but how Wnt ligand activity is locally restricted at the protein level is poorly understood.Here we report the identification of an astacin family proteinase as a Wnt processing factor. Hydra astacin-7 (HAS-7) is expressed from gland cells as an apical-distal gradient in the body column, peaking close beneath the tentacle zone. HAS-7 siRNA knockdown abrogates HyWnt3 proteolysis in the head tissue and induces a robust double axis phenotype, which is rescued by simultaneous HyWnt3 knockdown. Accordingly, double axes are also observed in conditions of increased Wnt levels as in transgenic actin::HyWnt3 and HyDkk1/2/4 siRNA treated animals. HyWnt3-induced double axes in Xenopus embryos could be rescued by co-injection of HAS-7 mRNA. Mathematical modelling combined with experimental promotor analysis indicate an indirect regulation of HAS-7 by beta-Catenin, expanding the classical Turing-type activator-inhibitor model.Our data suggest a negative regulatory function of Wnt processing astacin proteinases in the global patterning of the oral-aboral axis in Hydra.

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.

Genetic analysis of developmental mechanisms in Hydra. IV. Characterization of a nematocyst-deficient strain

1978 ◽  
Vol 30 (1) ◽  
pp. 175-185 ◽  
Author(s):  
T. Fujisawa ◽  
T. Sugiyama
Keyword(s):  
Genetic Analysis ◽  
Normal Level ◽  
The Body ◽  
Normal Rate ◽  
Wild Type ◽  
Head Region ◽  
Developmental Defects ◽  
Developmental Mechanisms ◽  
Body Column

The authors have previously found that mutant hydra strains showing various types of developmental defects can be isolated through sexual inbreeding of wild hydra. One such defective strain, called nem-4, contains virtually no stenoteles, one of the four types of nematocysts present in hydra, in its tentacles. However, stenoteles are present at a normal level in the body column of this strain, and they are turned over also at a normal rate. Grafting experiments between the head region of nem-4 hydra and the body column of wild type hydra (and vice versa) showed that wild type stenotele nematocytes can move into nem-4 tentacles but that nem-4 stenotele nematocytes can not move into the wild type tentacles. These observations suggest that the stenotele nematocytes are produced normally by differentiation from the interstitial cells in the body column of nem-4 hydra, but that they are somehow prevented from migrating into the tentacles in this strain.

Studies on the Characterization of Factor VIII and a Co-factor VIII

1974 ◽  
Vol 31 (02) ◽  
pp. 328-338
Author(s):  
M. M. P Paulssen ◽  
H. L. M. A Vandenbussche-Scheffers ◽  
P. B Spaan ◽  
T de Jong ◽  
M. C Planje
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
The Body ◽  
Haemophilia A ◽  
Von Willebrand's Disease ◽  
Von Willebrand’S Disease ◽  
Polysaccharide Content ◽  
Plasma Factor ◽  
Two Factors

SummaryFactor VIII occurs in the body in two different forms. In lymph factor VIII is bound to chylomicra. In plasma, factor VIII is bound to a protein.After delipidation of chylomicra we obtained a glycoprotein with a high polysaccharide content and a molecular weight of approx. 160,000.In plasma, factor VIII is attached to a protein which is present in normal concentrations in plasma of patients with haemophilia A and in serum (co-factor VIII).This factor is deficient in both the plasma and the serum of patients with von Willebrand’s disease.The binding between factor VIII and co-factor VIII is reversible.Some properties of these two factors are described.

The Sober Bacchae: Dance as Phenomenal Limitation in Nietzsche

2019 ◽  
Vol 37 (1) ◽  
pp. 59-76
Author(s):  
Monique Lyle
Keyword(s):  
World View ◽  
The Body ◽  
Specific Function ◽  
Alain Badiou ◽  
Classical Greece ◽  
Birth Of Tragedy

This essay seeks to dispel entrenched critical opinion regarding dance across Nietzsche's writings as representative of Dionysian intoxication alone. Taking as its prompt the riposte of Alain Badiou, ‘Nietzsche is miles away from any doctrine of dance as a primitive ecstasy’ and ‘dance is in no way the liberated bodily impulse, the wild energy of the body’, the essay uncovers the ties between dance and Apollo in the Nietzschean theory of art while qualifying dance's relation to Dionysus. Primarily through an analysis of The Dionysiac World View and The Birth of Tragedy, the essay seeks to illuminate enigmatic statements about dance in Nietzsche (‘in dance the greatest strength is only potential, although it is betrayed by the suppleness of movement’ and ‘dance is the preservation of orderly measure’). It does this through an elucidation of the specific function of dance in Nietzsche's interpretation of classical Greece; via an assessment of the difficulties associated with the Nietzschean understanding of the bacchanal; and lastly through an analysis of Nietzsche's characterization of dance as a symbol. The essay culminates in a discussion of dance's ties to Nietzschean life affirmation; here the themes of physico-phenomenal existence, joy and illusion in Nietzsche are surveyed.

Characterization of the glycoconjugates of boar testis and epididymis

Reproduction ◽  
2000 ◽  
pp. 325-335 ◽  
Author(s):  
A Calvo ◽  
LM Pastor ◽  
S Bonet ◽  
E Pinart ◽  
M Ventura
Keyword(s):  
Ricinus Communis ◽  
Lectin Histochemistry ◽  
Apical Part ◽  
Seminiferous Tubules ◽  
In Situ Characterization ◽  
Intense Staining ◽  
Terminal Galactose ◽  
Boar Spermatozoa

Lectin histochemistry was used to perform in situ characterization of the glycoconjugates present in boar testis and epididymis. Thirteen horseradish peroxidase- or digoxigenin-labelled lectins were used in samples obtained from healthy fertile boars. The acrosomes of the spermatids were stained intensely by lectins with affinity for galactose and N-acetyl-galactosamine residues, these being soybean, peanut and Ricinus communis agglutinins. Sertoli cells were stained selectively by Maackia ammurensis agglutinin. The lamina propria of seminiferous tubules showed the most intense staining with fucose-binding lectins. The Golgi area and the apical part of the principal cells of the epididymis were stained intensely with many lectins and their distribution was similar in the three zones of the epididymis. On the basis of lectin affinity, both testis and epididymis appear to have N- and O-linked glycoconjugates. Spermatozoa from different epididymal regions showed different expression of terminal galactose and N-acetyl-galactosamine. Sialic acid (specifically alpha2,3 neuraminic-5 acid) was probably incorporated into spermatozoa along the extratesticular ducts. These findings indicate that the development and maturation of boar spermatozoa are accompanied by changes in glycoconjugates. As some lectins stain cellular or extracellular compartments specifically, these lectins could be useful markers in histopathological evaluation of diseases of boar testis and epididymis.

In-vivo evaluation of cisplatin nanoparticles encompass natural polymer

2020 ◽  
Vol 6 (1) ◽  
pp. 1-7
Author(s):  
Bhavani J ◽  
Sunil Kumar Prajapati ◽  
Ravichandran S
Keyword(s):  
Tumor Volume ◽  
Nitrogen Mustard ◽  
Common Type ◽  
The Body ◽  
Nano Particles ◽  
Natural Polymer ◽  
Drinking Alcohol ◽  
In Vivo Evaluation

Cancer is assemblage diseases involving abnormal cell growth amid the potential of spread to other parts of the body due to tobacco use are the cause of about of cancer deaths. Another 10% is due to obesity, poor diet & drinking alcohol. In 2012 about 14.1 million new cases of cancer occurred globally. In females, the most common type is breast cancer. Cisplatin also known as cytophosphane is a nitrogen mustard alkylating agent from the oxazophosphinans groups were used to treat cancers & autoimmune disorders. Based on the above reasons I will fix the aim Preparation characterization of Cisplatin- nano particles  &  its anticancer activity. Solid tumor volume examination report showed that the assessment of different day indication 15,20,25 & 30th variations of different groups of tumor volumes were decreased CPG Nanoparticles (100 mg/kg)+ DAL(15th day 4.97±0.24↓), (20th day 0.6±0.13↓), (25th day 1.35±0.30↓) & (30th day 1.89±0.13↓).

scholarly journals Potential use of molecular and structural characterization of the gut bacterial community for postmortem interval estimation in Sprague Dawley rats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Huan Li ◽  
Siruo Zhang ◽  
Ruina Liu ◽  
Lu Yuan ◽  
Di Wu ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Interval Estimation ◽  
The Body ◽  
Taxon Richness ◽  
Time Since Death ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Level Data ◽  
Species Taxon

AbstractOnce the body dies, the indigenous microbes of the host begin to break down the body from the inside and play a key role thereafter. This study aimed to investigate the probable shift in the composition of the rectal microbiota at different time intervals up to 15 days after death and to explore bacterial taxa important for estimating the time since death. At the phylum level, Proteobacteria and Firmicutes showed major shifts when checked at 11 different intervals and emerged at most of the postmortem intervals. At the species level, Enterococcus faecalis and Proteus mirabilis showed a downward and upward trend, respectively, after day 5 postmortem. The phylum-, family-, genus-, and species-taxon richness decreased initially and then increased considerably. The turning point occurred on day 9, when the genus, rather than the phylum, family, or species, provided the most information for estimating the time since death. We constructed a prediction model using genus-level data from high-throughput sequencing, and seven bacterial taxa, namely, Enterococcus, Proteus, Lactobacillus, unidentified Clostridiales, Vagococcus, unidentified Corynebacteriaceae, and unidentified Enterobacteriaceae, were included in this model. The abovementioned bacteria showed potential for estimating the shortest time since death.

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