The Nature of Growth Inhibitory Material from Crowded Rana Pipiens Tadpoles

1960 ◽  
Vol 33 (3) ◽  
pp. 232-239 ◽  
Author(s):  
Lorna B. West
Author(s):  
J. R. Ruby ◽  
R. F. Dyer ◽  
R. G. Skalko ◽  
R. F. Gasser ◽  
E. P. Volpe

An electron microscope examination of fetal ovaries has revealed that developing germ cells are connected by intercellular bridges. In this investigation several species have been studied including human, mouse, chicken, and tadpole (Rana pipiens). These studies demonstrate that intercellular connections are similar in morphology regardless of the species.Basically, all bridges are characterized by a band of electron-dense material on the cytoplasmic side of the tri-laminar membrane surrounding the connection (Fig.l). This membrane is continuous with the plasma membrane of the conjoined cells. The dense material, however, never extends beyond the limits of the bridge. Variations in the configuration of intercellular connections were noted in all ovaries studied. However, the bridges in each individual species usually exhibits one structural characteristic seldom found in the others. For example, bridges in the human ovary very often have large blebs projecting from the lateral borders whereas the sides of the connections in the mouse gonad merely demonstrate a slight convexity.


Author(s):  
J. H. Hayden

In a previous study, Allen video-enhanced constrast/differential interference constrast (AVEC-DIC) microscopy was used in conjunction with immunofluorescence microscopy to demonstrate that organelles and vesicle move in either direction along linear elements composed of microtubules. However, this study was limited in that the number of microtubules making up a linear element could not be determined. To overcome this limitation, we have used AVEC-DIC microscopy in conjunction with whole mount electron microscopy.Keratocytes from Rana pipiens were grown on glass coverslips as described elsewhere. Gold London Finder grids were Formvar- and carbon coated, and sterilized by exposure to ultraviolet light. It is important to select a Formvar film that gives a grey reflection when it is floated on water. A silver film is too thick and will detract from the image in the light microscope.


Planta Medica ◽  
2012 ◽  
Vol 78 (11) ◽  
Author(s):  
F Epifano ◽  
S Genovese ◽  
P Lullo ◽  
S Fiorito ◽  
G Trivisonno ◽  
...  

2020 ◽  
Vol 20 (14) ◽  
pp. 1264-1273 ◽  
Author(s):  
Bruno Casciaro ◽  
Floriana Cappiello ◽  
Walter Verrusio ◽  
Mauro Cacciafesta ◽  
Maria Luisa Mangoni

The frequent occurrence of multidrug-resistant strains to conventional antimicrobials has led to a clear decline in antibiotic therapies. Therefore, new molecules with different mechanisms of action are extremely necessary. Due to their unique properties, antimicrobial peptides (AMPs) represent a valid alternative to conventional antibiotics and many of them have been characterized for their activity and cytotoxicity. However, the effects that these peptides cause at concentrations below the minimum growth inhibitory concentration (MIC) have yet to be fully analyzed along with the underlying molecular mechanism. In this mini-review, the ability of AMPs to synergize with different antibiotic classes or different natural compounds is examined. Furthermore, data on microbial resistance induction are reported to highlight the importance of antibiotic resistance in the fight against infections. Finally, the effects that sub-MIC levels of AMPs can have on the bacterial pathogenicity are summarized while showing how signaling pathways can be valid therapeutic targets for the treatment of infectious diseases. All these aspects support the high potential of AMPs as lead compounds for the development of new drugs with antibacterial and immunomodulatory activities.


2021 ◽  
Vol 14 (1) ◽  
pp. 49
Author(s):  
David Méndez-Luna ◽  
Loreley Araceli Morelos-Garnica ◽  
Juan Benjamín García-Vázquez ◽  
Martiniano Bello ◽  
Itzia Irene Padilla-Martínez ◽  
...  

The implementation of chemo- and bioinformatics tools is a crucial step in the design of structure-based drugs, enabling the identification of more specific and effective molecules against cancer without side effects. In this study, three new compounds were designed and synthesized with suitable absorption, distribution, metabolism, excretion and toxicity (ADME-tox) properties and high affinity for the G protein-coupled estrogen receptor (GPER) binding site by in silico methods, which correlated with the growth inhibitory activity tested in a cluster of cancer cell lines. Docking and molecular dynamics (MD) simulations accompanied by a molecular mechanics/generalized Born surface area (MMGBSA) approach yielded the binding modes and energetic features of the proposed compounds on GPER. These in silico studies showed that the compounds reached the GPER binding site, establishing interactions with a phenylalanine cluster (F206, F208 and F278) required for GPER molecular recognition of its agonist and antagonist ligands. Finally, a 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay showed growth inhibitory activity of compounds 4, 5 and 7 in three different cancer cell lines—MIA Paca-2, RCC4-VA and Hep G2—at micromolar concentrations. These new molecules with specific chemical modifications of the GPER pharmacophore open up the possibility of generating new compounds capable of reaching the GPER binding site with potential growth inhibitory activities against nonconventional GPER cell models.


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