An Analysis of the Postgastrula Differentiation of the Hypomere

Development ◽  
1961 ◽  
Vol 9 (2) ◽  
pp. 294-309
Author(s):  
Cyril V. Finnegan
Keyword(s):  
Early Age ◽  
In Vitro Experiments ◽  
Experimental Conditions ◽  
Tissue Mass ◽  
Intimate Association ◽  
Insight Into

Since the publication of earlier papers (Finnegan, 1953, 1955) the investigation of the capacity of the salamander hypomeric mesoderm for histogenesis under a variety of experimental conditions has continued. It is perhaps prudent at this time to initiate a series of reports with results obtained from in vitro experiments which were designed to gain some insight into the roles of competence, tissue mass, and endodermal influence relative to hypomeric differentiation in Ambystoma. This portion of the mesoderm is destined to undergo its differentiation far removed from the dorsal axial influences of the chorda-mesoderm but with its inner (splanchnic) material in rather intimate association with the endoderm, a tissue known to be determined at an early age and metabolically active, two conditions which lead one to suspect it of inductor potentialities (Nieuwkoop, 1947; Copenhaver, 1955).

Trematodes and snails: an intimate association

2004 ◽  
Vol 82 (2) ◽  
pp. 251-269 ◽  
Author(s):  
Anne E Lockyer ◽  
Catherine S Jones ◽  
Leslie R Noble ◽  
David Rollinson
Keyword(s):  
Evolutionary History ◽  
Intermediate Hosts ◽  
Molecular Approaches ◽  
Complex Interactions ◽  
Intimate Association ◽  
In Vitro Cell Cultures ◽  
Medical Burden ◽  
Insight Into ◽  
Trematode Parasites

Trematode parasites share an intimate relationship with their gastropod intermediate hosts, which act as the vehicle for their development and transmission. They represent an enormous economic and medical burden in developing countries, stimulating much study of snail–trematode interactions. Laboratory-maintained snail–trematode systems and in vitro cell cultures are being used to investigate the molecular dialogue between host and parasite. These dynamic and finely balanced antagonistic relationships, in which parasites strongly influence the physiology of the host, are highly specific and may occasionally demonstrate co-speciation. We consider the mechanisms and responses deployed by trematodes and snails that result in compatibility or rejection of the parasite, and the macroevolutionary implications that they may effect. Although for gastropods the fossil record gives some insight into evolutionary history, elucidation of trematode evolution must rely largely upon molecular approaches, and for both, such techniques have provided fresh and often surprising evidence of their origins and dispersal over time. Co-evolution of snails and trematodes is becoming increasingly apparent at both cellular and population levels; the implications of which are only beginning to be understood for disease control. Untangling the complex interactions of trematodes and snails promise fresh opportunities for intervention to relieve the burden of parasitic disease.

In Vitro Models for Studying Renal Stone Formation: A Clear Alternative

1998 ◽  
Vol 26 (4) ◽  
pp. 481-503
Author(s):  
Felix Grases ◽  
Rafael M. Prieto ◽  
Antonia Costa-Bauzá
Keyword(s):  
Renal Stone ◽  
Stone Formation ◽  
Renal Stones ◽  
Renal Calculi ◽  
In Vitro Models ◽  
Laboratory Animals ◽  
In Vitro Experiments ◽  
Experimental Conditions

This paper discusses the limitations of using laboratory animals for direct in vivo observation of the development of renal stones. In fact, the majority of hypotheses related to mechanisms of stone formation have been based on the results of in vitro experiments. The relevance of in vitro experiments that allow the study of urolithiasis depends upon the degree of correspondence between the experimental conditions and those prevailing in the stone-forming kidney in vivo. For this reason, several in vitro experimental systems that attempt to reproduce the conditions found in vivo have been developed in order to study renal stone formation, which have been classified into two main groups: a) models to study papillary stone formation; and b) models to study “sedimentary” stone formation. These models are briefly described in this paper, and the information obtained was compared with that resulting from a study of the fine structure of real human renal calculi, in order to prove the validity of the models. It was concluded that the experimental in vitro models can closely reproduce the renal conditions under which human calculi are developed. This allows important data to be obtained about the aetiology of renal lithiasis, which is of great relevance to the development of effective treatments for this disease. Therefore, experimental in vitro models constitute a clear alternative to the use of laboratory animals.

A Simulator for the In Vitro Study of the Dynamics of the Aortic Valve: Design and Test

2009 ◽  
Author(s):  
Riccardo Vismara ◽  
Dario Comparolo ◽  
Andrea Mangini ◽  
Carlo Antona ◽  
Gianfranco B. Fiore
Keyword(s):  
Animal Models ◽  
Aortic Valve ◽  
Heart Valves ◽  
In Vitro Study ◽  
Vitro Study ◽  
Valve Design ◽  
Experimental Conditions ◽  
Insight Into ◽  
Physiological Complexity

The in vitro approach to the study of the hemodynamics of heart valves allows easier-to-control and well repeatable experimental conditions, if compared with studies on animal models. A deep, detailed insight into specific issues is possible, despite the unavoidable simplification of the physiological complexity.

scholarly journals Carbon Nanodots Synthesized from Dunaliella salina as Sun Protection Filters

2020 ◽  
Vol 6 (4) ◽  
pp. 69
Author(s):  
Theodoros G. Chatzimitakos ◽  
Athanasia Kasouni ◽  
Anastassios Troganis ◽  
Ioannis Leonardos ◽  
Ioannis Tzovenis ◽  
...  
Keyword(s):  
Wound Healing ◽  
Citric Acid ◽  
Dunaliella Salina ◽  
Sun Protection ◽  
Uv Protection ◽  
Carbon Nanodots ◽  
The Sun ◽  
In Vitro Experiments ◽  
Insight Into

Carbon nanodots (CNDs) are more and more being exploited for various applications including biological ones. To this end, they have been thoroughly studied for their potential as antibacterial, wound healing, and bioimaging agents. In this study, we examined the sun protection properties of CNDs. Dunaliella salina was selected as a promising precursor for the synthesis of CNDs which were compared with those produced by citric acid, a widely used precursor for such materials. The CNDs were examined spectrophotometrically, and the sun protection factors were calculated. Additionally, in vitro experiments were carried out to evaluate their UV protection properties and to obtain better insight into whether CNDs are suitable to be used as filters for the development of new sunscreens. The results were conclusive that both CNDs possess favorable properties that potentiate their use for the development of sunscreens. However, the CNDs from Dunaliella salina were found to be superior to those derived from citric acid. Therefore, they can further be exploited as sun protection filters.

scholarly journals Improving Phage-Biofilm In Vitro Experimentation

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1175
Author(s):  
Stephen T. Abedon ◽  
Katarzyna M. Danis-Wlodarczyk ◽  
Daniel J. Wozniak ◽  
Matthew B. Sullivan
Keyword(s):  
Viable Count ◽  
Bacterial Biofilms ◽  
In Vitro Experiments ◽  
Experimental Conditions ◽  
Biofilm Growth ◽  
Bacterial Ecology ◽  
End Point ◽  
Biofilm Disruption ◽  
Free Phage

Bacteriophages or phages, the viruses of bacteria, are abundant components of most ecosystems, including those where bacteria predominantly occupy biofilm niches. Understanding the phage impact on bacterial biofilms therefore can be crucial toward understanding both phage and bacterial ecology. Here, we take a critical look at the study of bacteriophage interactions with bacterial biofilms as carried out in vitro, since these studies serve as bases of our ecological and therapeutic understanding of phage impacts on biofilms. We suggest that phage-biofilm in vitro experiments often may be improved in terms of both design and interpretation. Specific issues discussed include (a) not distinguishing control of new biofilm growth from removal of existing biofilm, (b) inadequate descriptions of phage titers, (c) artificially small overlying fluid volumes, (d) limited explorations of treatment dosing and duration, (e) only end-point rather than kinetic analyses, (f) importance of distinguishing phage enzymatic from phage bacteriolytic anti-biofilm activities, (g) limitations of biofilm biomass determinations, (h) free-phage interference with viable-count determinations, and (i) importance of experimental conditions. Toward bettering understanding of the ecology of bacteriophage-biofilm interactions, and of phage-mediated biofilm disruption, we discuss here these various issues as well as provide tips toward improving experiments and their reporting.

Clonal propagation and the fast generation of karyotype diversity: anin vitro Leishmaniamodel

Parasitology ◽  
2006 ◽  
Vol 134 (1) ◽  
pp. 33-39 ◽  
Author(s):  
J.-C. DUJARDIN ◽  
S. DE DONCKER ◽  
D. JACQUET ◽  
A.-L. BAÑULS ◽  
M. BALAVOINE ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Incubation Temperature ◽  
Growth Behaviour ◽  
Experimental Conditions ◽  
Aberrant Chromosome ◽  
Homologous Chromosomes ◽  
Additional Chromosome ◽  
Insight Into

In the present work we studied the karyotype stability during long-termin vitromaintenance in 3 cloned strains ofLeishmania (Viannia) peruviana,Leishmania (Viannia) braziliensisand a hybrid between both species. Only theL. (V.) peruvianastrain showed an unstable karyotype, even after subcloning. Four chromosomes were studied in detail, each of them characterized by homologous chromosomes of different size (heteromorphy). Variations in chromosome patterns duringin vitromaintenance were rapid and discrete, involving loss of heteromorphy or appearance of additional chromosome size variants. The resulting pattern was not the same according to experimental conditions (subinoculation rate or incubation temperature), and interestingly, this was associated with differences in growth behaviour of the respective parasites. No change in total ploidy of the cells was observed by flow cytometry. We discuss several mechanisms that might account for this variation of chromosome patterns, but we favour the occurrence of aneuploidy, caused by aberrant chromosome segregation during mitosis. Our results provide insight into the generation of karyotype diversity in natural conditions and highlight the relativity of the clone concept in parasitology.

scholarly journals In Silico Experiments in Scientific Papers on Molecular Biology

2011 ◽  
Vol 24 (2) ◽  
pp. 23-42
Author(s):  
Sabrina Moretti
Keyword(s):  
Molecular Biology ◽  
In Silico ◽  
In Vitro Experiments ◽  
Technical Object ◽  
Experimental Conditions ◽  
Biological Phenomena ◽  
Scientific Papers

This article explores the role of the so-called in silico experiments used in molecular biology. It is based on the analysis of some papers that present scientific applications which rely on in silico experiments. By means of this study I found two basic ways of viewing them. According to the first view, the in silico experiment is a computer program that realizes some specific operations: it constitutes some particular experimental conditions, which allow us to investigate biological phenomena, and which complement those present in in vivo and in vitro experiments. According to the second view, in silico experimentation has a different meaning, which corresponds more closely to the meaning of “simulation”: its identity is linked to that of the “model” used to construct such simulation. The authors of the analysed papers never express an intention to standardize a model, so its meaning remains contingent, and cannot be turned into a technical object.

Humoral induction of pyloric rhythmic output in lobster stomatogastric ganglion: in vivo and in vitro studies

1992 ◽  
Vol 163 (1) ◽  
pp. 209-230
Author(s):  
E. Rezer ◽  
M. Moulins
Keyword(s):  
Blood Serum ◽  
Stomatogastric Ganglion ◽  
In Vitro Studies ◽  
In Vitro Experiments ◽  
Experimental Conditions ◽  
Pyloric Network ◽  
Pyloric Rhythm

In the lobster Jasus lalandii, 14 neurones of the stomatogastric ganglion (STG) are organized in a network that produces rhythmic pyloric outputs. In vitro experiments have shown that the STG neurones receive, via the stomatogastric nerve (stn), neuromodulatory inputs that influence the expression of the bursting properties of the neurones and the ability of the network to produce its rhythmic output. In contrast to these in vitro observations, in vivo transection of the stn does not abolish the pyloric rhythm. Rhythmic output can be recorded by electromyography immediately after stn transection and for up to 2 years afterwards. We have shown that, under these experimental conditions, the STG appears to be isolated from any neuronal input that might account for the maintenance of the rhythmic output. Experiments carried out in the 2 days after stn transection showed that an in vitro preparation of the isolated STG was unable to produce any rhythmic output, but blood serum added to the system could restore the pyloric output. These results suggest strongly that the pyloric network receives neural and humoral modulatory influences in parallel and that each type of influence alone is able to maintain the bursting capability of the pyloric neurones.

scholarly journals Revisiting the Non-Coding Nature of Pospiviroids

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 265
Author(s):  
Konstantina Katsarou ◽  
Charith Raj Adkar-Purushothama ◽  
Emilios Tassios ◽  
Martina Samiotaki ◽  
Christos Andronis ◽  
...  
Keyword(s):  
Unknown Function ◽  
Bioinformatic Analysis ◽  
Economic Losses ◽  
In Vitro Experiments ◽  
Experimental Conditions ◽  
Circular Form ◽  
Size And Structure

Viroids are small, circular, highly structured pathogens that infect a broad range of plants, causing economic losses. Since their discovery in the 1970s, they have been considered as non-coding pathogens. In the last few years, the discovery of other RNA entities, similar in terms of size and structure, that were shown to be translated (e.g., cirRNAs, precursors of miRNA, RNA satellites) as well as studies showing that some viroids are located in ribosomes, have reignited the idea that viroids may be translated. In this study, we used advanced bioinformatic analysis, in vitro experiments and LC-MS/MS to search for small viroid peptides of the PSTVd. Our results suggest that in our experimental conditions, even though the circular form of PSTVd is found in ribosomes, no produced peptides were identified. This indicates that the presence of PSTVd in ribosomes is most probably not related to peptide production but rather to another unknown function that requires further study.

Neurofilaments and Paired Helical Filaments

1985 ◽  
Vol 43 ◽  
pp. 740-743
Author(s):  
J. Metuzals
Keyword(s):  
Animal Model ◽  
Posttranslational Modifications ◽  
Posttranslational Modification ◽  
Giant Axon ◽  
Paired Helical Filaments ◽  
Squid Giant Axon ◽  
In Vitro Experiments ◽  
Thin Sections ◽  
Structural Relationships

It has been demonstrated that the neurofibrillary tangles in biopsies of Alzheimer patients, composed of typical paired helical filaments (PHF), consist also of typical neurofilaments (NF) and 15nm wide filaments. Close structural relationships, and even continuity between NF and PHF, have been observed. In this paper, such relationships are investigated from the standpoint that the PHF are formed through posttranslational modifications of NF. To investigate the validity of the posttranslational modification hypothesis of PHF formation, we have identified in thin sections from frontal lobe biopsies of Alzheimer patients all existing conformations of NF and PHF and ordered these conformations in a hypothetical sequence. However, only experiments with animal model preparations will prove or disprove the validity of the interpretations of static structural observations made on patients. For this purpose, the results of in vitro experiments with the squid giant axon preparations are compared with those obtained from human patients. This approach is essential in discovering etiological factors of Alzheimer's disease and its early diagnosis.

Sign in / Sign up

Export Citation Format

Share Document