The effect of fibronectin and substratum-attached material on the spreading of chick embryo mesoderm cells in vitro

1980 ◽  
Vol 44 (1) ◽  
pp. 225-242
Author(s):  
E.J. Sanders
Keyword(s):  
Dorsal Surface ◽  
The Other ◽  
Plasma Fibronectin ◽  
Normal Medium ◽  
Attachment Sites ◽  
Epithelial Sheet ◽  
Low Levels ◽  
Epithelial Sheets ◽  
Scanning Electron

Endoblast and hypoblast tissue, dissected from early chick embryos, was explanted and cultured on glass or plastic substrata. These tissues grew rapidly to form epithelial sheets. Under the same conditions, mesoderm, dissected without the aid of dissociating agents, grew poorly. After 24 h in culture, the mesoderm explants consisted of a sparse outgrowth of fibroblast-like cells. When pieces of mesoderm were seeded onto the dorsal surface of the epithelia, however, the cells penetrated the sheet and rapidly spread on the substratum within 4 h. If the epithelial sheet was detached from the substratum and the mesoderm then seeded onto areas of substratum previously occupied by epithelium, similar rapid spreading occurred. This effect could be produced in the absence of serum. The method used to remove the epithelium (EDTA, detergent or manual dissection) did not influence the result. When the substratum-attached material (SAM) was examined by scanning electron microscopy, 2 types of material were seen. One type appeared to be the remains of detached filopodia and cytoplasmic lamellae, while the other appeared to be of extracellular origin. Both these types reacted positively by immunofluorescence using anti-fibronectin serum. SAM derived from mesoderm reacted negatively. When mesoderm was cultured in the presence of plasma fibronectin on unmodified plastic or glass, spreading was complete in 4–5 h and thus was similar to mesoderm seeded onto SAM. The morphology of mesoderm explants on SAM or in the presence of plasma fibronectin was more epithelial than on untreated substratum in normal medium. Hypoblast and endoblast cultured in the presence of anti-fibronectin serum failed to spread normally, apparently being unable to attach to the substratum. Mesoderm did not spread rapidly on SAM in the presence of this antiserum. Cycloheximide reversibly inhibited the spreading of hypoblast and endoblast, and this effect could be eliminated, at least for hypoblast, by the addition of plasma fibronectin. Covering attachment sites on the substratum with bovine serum albumin, thereby preventing the attachment of SAM or fibronectin, also inhibited spreading. It is proposed that mesoderm cells have low levels of surface fibronectin in comparison with endoblast and hypoblast, and that this results in a comparatively low adhesiveness, which is important for its morphogenetic activity within the embryo.

scholarly journals Specificity and Regulation of Interaction between the PII and AmtB1 Proteins in Rhodospirillum rubrum

2007 ◽  
Vol 189 (19) ◽  
pp. 6861-6869 ◽  
Author(s):  
David M. Wolfe ◽  
Yaoping Zhang ◽  
Gary P. Roberts
Keyword(s):  
Rhodospirillum Rubrum ◽  
Regulatory Protein ◽  
The Other ◽  
Ammonia Gas ◽  
Gas Channel ◽  
Energy Sensor ◽  
Low Levels

ABSTRACT The nitrogen regulatory protein PII and the ammonia gas channel AmtB are both found in most prokaryotes. Interaction between these two proteins has been observed in several organisms and may regulate the activities of both proteins. The regulation of their interaction is only partially understood, and we show that in Rhodospirillum rubrum one PII homolog, GlnJ, has higher affinity for an AmtB1-containing membrane than the other two PII homologs, GlnB and GlnK. This interaction strongly favors the nonuridylylated form of GlnJ and is disrupted by high levels of 2-ketoglutarate (2-KG) in the absence of ATP or low levels of 2-KG in the presence of ATP. ADP inhibits the destabilization of the GlnJ-AmtB1 complex in the presence of ATP and 2-KG, supporting a role for PII as an energy sensor measuring the ratio of ATP to ADP. In the presence of saturating levels of ATP, the estimated Kd of 2-KG for GlnJ bound to AmtB1 is 340 μM, which is higher than that required for uridylylation of GlnJ in vitro, about 5 μM. This supports a model where multiple 2-KG and ATP molecules must bind a PII trimer to stimulate release of PII from AmtB1, in contrast to the lower 2-KG requirement for productive uridylylation of PII by GlnD.

scholarly journals In VitroAdherence of Oral Bacteria to Different Types of Tongue Piercings

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Lucas Pereira Borges ◽  
Julio Cesar Campos Ferreira-Filho ◽  
Julia Medeiros Martins ◽  
Caroline Vieira Alves ◽  
Bianca Marques Santiago ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Adhesion ◽  
Oral Bacteria ◽  
The Other ◽  
Control Group ◽  
Colony Forming Units ◽  
Different Types ◽  
Scanning Electron

The purpose of this work was to verifyin vitroadherence ofE. corrodensandS. oralisto the surface of tongue piercings made of surgical steel, titanium, Bioplast, and Teflon. For this, 160 piercings were used for the count of Colony Forming Units (CFU) and 32 piercings for analysis under scanning electron microscopy. Of these, 96 (24 of each type) were individually incubated in 5 mL of BHI broth and 50 μL of inoculum at 37°C/24 h. The other 96 piercings formed the control group and were individually incubated in 5 mL of BHI broth at 37°C/24 h. Plates were incubated at 37°C/48 h for counting of CFU/mL and data were submitted to statistical analysis (pvalue<0.05). ForE. corrodens, difference among types of material was observed (p<0.001) and titanium and surgical steel showed lower bacterial adherence. The adherence ofS. oralisdiffered among piercings, showing lower colonization (p<0.007) in titanium and surgical steel piercings. The four types of piercings were susceptible to colonization byE. corrodensandS. oralis, and bacterial adhesion was more significant in those made of Bioplast and Teflon. The piercings presented bacterial colonies on their surface, being higher in plastic piercings probably due to their uneven and rough surface.

scholarly journals Evaluation of biofilm accumulation on and deactivation force of orthodontic Ni-Ti archwires before and after exposure to an oral medium: A prospective clinical study

2020 ◽  
Vol 14 (1) ◽  
pp. 41-47
Author(s):  
Diogo M. Sapata ◽  
Adilson L. Ramos ◽  
Sérgio Sábio ◽  
David Normando ◽  
Renata C. Pascotto
Keyword(s):  
Repeated Measures ◽  
In Vitro Study ◽  
The Other ◽  
Prospective Clinical Study ◽  
Test Machine ◽  
Before And After ◽  
Post Test ◽  
Spearman Test ◽  
Scanning Electron

Background . This in vitro study aimed to evaluate biofilm accumulation on and deactivation force of orthodontic nickeltitanium (NiTi) archwires before and after exposure to an oral medium. Methods. Four commercial brands of orthodontic NiTi 0.016" archwires were examined before and after exposure to the oral medium for 4 weeks. Six archwire segments, 30 mm in length, from each manufacturer were tested in a device with four selfligating brackets, channel 0.022", adapted to a universal test machine to evaluate the deactivation force between 0.5 and 3 mm of deflection. The presence of biofilm on the archwire surfaces was evaluated by scanning electron microscopy, before and after exposure to the oral medium. The Wilcoxon and kappa tests were applied to the biofilm scores, three-way ANOVA for repeated measures (Bonferroni post-test), and linear regression between biofilm and deactivation force. Results. The exposure to the oral medium promoted moderate to severe presence of debris on the archwire surfaces and caused a reduction in deactivation force for the Ormco and GAC brands, while maintaining them with adequate force levels. The MORELLI and ORTHOMETRIC archwires underwent no significant reduction in deactivation force; moreover, these maintained elevated levels of force after exposure to the oral medium. The Spearman test indicated a low correlation between biofilm accumulation and deflection force for the Morelli (R2=0.132 and P=0.683) and Orthometric (R2=0.308 and P=0.330) brands. On the other hand, the GAC (R=0.767 and P=0.004) and ORMCO (R=0.725 and P=0.008) brands exhibited statistically significant correlation between these variables. Conclusion. Exposure to the oral medium for one month might give rise to significant changes in the dissipation of forces of orthodontic NiTi archwires, resulting from biofilm accumulation.

scholarly journals In Vitro and In Vivo Activities of CS-758 (R-120758), a New Triazole Antifungal Agent

2002 ◽  
Vol 46 (2) ◽  
pp. 367-370 ◽  
Author(s):  
Yasuki Kamai ◽  
Tamako Harasaki ◽  
Takashi Fukuoka ◽  
Satoshi Ohya ◽  
Katsuhisa Uchida ◽  
...  
Keyword(s):  
Body Weight ◽  
Amphotericin B ◽  
Antifungal Agent ◽  
The Other ◽  
In Vitro Activity ◽  
Effective Doses ◽  
Low Levels ◽  
Systemic Infections

ABSTRACT The activity of CS-758 (R-120758), a new triazole antifungal agent, was evaluated and compared with those of fluconazole, itraconazole, and amphotericin B in vitro and with those of fluconazole and itraconazole in vivo. CS-758 exhibited potent in vitro activity against clinically important fungi. The activity of CS-758 against Candida spp. was superior to that of fluconazole and comparable or superior to those of itraconazole and amphotericin B. CS-758 retained potent activity against Candida albicans strains with low levels of susceptibility to fluconazole (fluconazole MIC, 4 to 32 μg/ml). Against Aspergillus spp. and Cryptococcus neoformans, the activity of CS-758 was at least fourfold superior to those of the other drugs tested. CS-758 also exhibited potent in vivo activity against murine systemic infections caused by C. albicans, C. neoformans, Aspergillus fumigatus, and Aspergillus flavus. The 50% effective doses against these infections were 0.41 to 5.0 mg/kg of body weight. These results suggest that CS-758 may be useful in the treatment of candidiasis, cryptococcosis, and aspergillosis.

THE RELATIONSHIP BETWEEN THE GLUTATHIONE CONTENT OF RAT ERYTHROCYTES AND THEIR HEMOLYSIS BY VARIOUS AGENTS IN VITRO

1960 ◽  
Vol 38 (1) ◽  
pp. 981-987 ◽  
Author(s):  
C. C. Tsen ◽  
H. B. Collier
Keyword(s):  
Heavy Metal ◽  
Silver Nitrate ◽  
Mercuric Chloride ◽  
Direct Action ◽  
The Other ◽  
Rat Erythrocytes ◽  
Experimental Conditions ◽  
Low Levels ◽  
The Relationship

Erythrocytes from rats on tocopherol-deficient diets are susceptible to hemolysis by dialuric acid or by shaking in an atmosphere of oxygen, whereas the erythrocytes from rats on tocopherol-supplemented diets are relatively insusceptible. The erythrocytes from the tocopherol-deficient and tocopherol-supplemented rats initially showed identical levels of free glutathione as determined by the alloxan "305" method; treatment with dialuric acid or exposure to oxygen reduced the glutathione levels in both groups of cells, yet in no case did the extent of hemolysis parallel the decrease in glutathione.Treatment of rat erythrocytes with selenite or iodoacetate or N-ethylmaleimide decreased the glutathione content of the cells to very low levels, yet there was little hemolysis. Silver nitrate, mercuric chloride, or p-chloromercuribenzoate, on the other hand, could cause complete hemolysis with little or no decrease in the levels of erythrocyte free glutathione. There were no significant differences between the erythrocytes from tocopherol-deficient and tocopherol-supplemented animals in these experiments.It is concluded that the susceptibility to hemolysis, under our experimental conditions, is not related to the level of erythrocyte glutathione. The heavy-metal sulphydryl reagents probably cause hemolysis by a direct action upon the erythrocyte membrane.

Effect of Vital Bleaching on Micromorphology of Enamel Surface: an in Vitro Study

2021 ◽  
Vol 10 (1) ◽  
pp. 126-131
Author(s):  
Zakaria Karimi ◽  
Houda Saoui ◽  
Majid Sakout ◽  
Faiza Abdallaoui
Keyword(s):  
In Vitro Study ◽  
Sem Analysis ◽  
Vitro Study ◽  
Enamel Surface ◽  
The Other ◽  
Bleaching Agent ◽  
Surface Porosity ◽  
Scanning Electron ◽  
At Home

Objectives: The aims of this in vitro study was to investigate the effects of bleaching agents commonly used in micromorphology of the enamel surface and to assess the effect of concentration and of adding fluoride in the bleaching agents. Methods: Sixty freshly extracted intact teeth were stored in distilled water. One half of each tooth was served as control, the other part was treated with bleaching agent. Samples were randomly divided into six groups of ten, according to the bleaching agents: G1- at-home-CP10; G2- at-home-CP16; G3- at-home-CP22; G4- in-office-CP35; G5- in-office-HP40 with fluoride; G6- in-office-HP40 without fluoride. Enamel specimens for each group were then submitted to a quantitative scanning electron microscopy. Number of pores and their diameter were measured to assess porosity of enamel surface. Results: SEM analysis revealed enamel surface porosity after bleaching. Significant increase in number and major diameter of pores in bleached samples (p<0.001) were observed. The comparison between samples treated with 10% PC and samples treated with 22% PC showed significant increase in number of pores (p=0.006) and major diameter (p=0.001) from samples treated with 22% PC. Statistical analyses showed significant increase in the number of pores (p=0.006) from samples treated with 40% HP without fluoride compared to samples treated with 40% HP containing fluoride. Conclusions: Bleaching products with low concentration cause less porosity at surface of the enamel compared to concentrated products. Adding fluoride in the bleaching agent appears to reduce porosity of enamel surface.

THE RELATIONSHIP BETWEEN THE GLUTATHIONE CONTENT OF RAT ERYTHROCYTES AND THEIR HEMOLYSIS BY VARIOUS AGENTS IN VITRO

1960 ◽  
Vol 38 (9) ◽  
pp. 981-987 ◽  
Author(s):  
C. C. Tsen ◽  
H. B. Collier
Keyword(s):  
Heavy Metal ◽  
Silver Nitrate ◽  
Mercuric Chloride ◽  
Direct Action ◽  
The Other ◽  
Rat Erythrocytes ◽  
Experimental Conditions ◽  
Low Levels ◽  
The Relationship

Erythrocytes from rats on tocopherol-deficient diets are susceptible to hemolysis by dialuric acid or by shaking in an atmosphere of oxygen, whereas the erythrocytes from rats on tocopherol-supplemented diets are relatively insusceptible. The erythrocytes from the tocopherol-deficient and tocopherol-supplemented rats initially showed identical levels of free glutathione as determined by the alloxan "305" method; treatment with dialuric acid or exposure to oxygen reduced the glutathione levels in both groups of cells, yet in no case did the extent of hemolysis parallel the decrease in glutathione.Treatment of rat erythrocytes with selenite or iodoacetate or N-ethylmaleimide decreased the glutathione content of the cells to very low levels, yet there was little hemolysis. Silver nitrate, mercuric chloride, or p-chloromercuribenzoate, on the other hand, could cause complete hemolysis with little or no decrease in the levels of erythrocyte free glutathione. There were no significant differences between the erythrocytes from tocopherol-deficient and tocopherol-supplemented animals in these experiments.It is concluded that the susceptibility to hemolysis, under our experimental conditions, is not related to the level of erythrocyte glutathione. The heavy-metal sulphydryl reagents probably cause hemolysis by a direct action upon the erythrocyte membrane.

Behavioural transformation in chick yolk-sac cells

Development ◽  
1974 ◽  
Vol 31 (3) ◽  
pp. 599-610
Author(s):  
J. Roger Downie
Keyword(s):  
Large Scale ◽  
Culture Conditions ◽  
Yolk Sac ◽  
Vitelline Membrane ◽  
In Ovo ◽  
Epithelial Sheet ◽  
Epithelial Sheets ◽  
Yolk Sac Cells

During the first 3 to 4 days of development in the chick, the extraembryonic part, the yolk-sac, expands to encompass the yolk mass. The yolk-sac, initially a two-layered epithelial sheet, is pulled out by the action of a specialized band of cells at its periphery. These attach to the overlying vitelline membrane and move out over it. However, unincubated blastoderms are not attached to the vitelline membrane, and each comprises a loose assemblage of rounded cells, not an epithelial sheet. The transformation of the unincubated blastoderm into an actively expanding epithelial sheet has been followed in culture, using hanging-drop cultures of fragments to observe large-scale behaviour, and disaggregated blastoderms to observe individual cell behaviour. The timing of events in culture accords well with related events in ovo, and the possibility that in vitro changes are merely a response to culture conditions has been largely excluded. 0−6 h in ovo. No cells attached to the vitelline membrane. All cells loosely attached to one another. 0−6 h in vitro. Cells do not attach to the glass. The cells of disaggregated blastoderms are rounded and stationary. 6−10 h in ovo. Cells at the blastoderm periphery attach to the vitelline membrane inner surface, but expansion does not start. The cells remain loosely attached to one another. 6−10 h in vitro. Cells begin to stick to the glass surface. Cells from disaggregated cultures move around as individuals. They remain rounded with long, narrow filopodia. If two cells collide, the adhesion tends to be brief. 10 + h in ovo. The blastoderm starts to expand rapidly as a cohesive epithelial sheet, pulled by its specialized ‘edge’ cells. All yolk-sac cells become tightly attached to one another. 10 + h in vitro. Blastoderm fragments start to spread rapidly as flattened epithelial sheets. There is no sign of specialized ‘edge’ cells. Cells at the periphery of any fragment take on the role of the edge. Cells from disaggregated cultures flatten out on the glass with wide lamellae all round. When two cells collide, they now tend to stick permanently together. The role of these changes in the mechanics of blastoderm expansion is briefly discussed.

Fungitoxic Activity of 12 Essential Oils against Four Postharvest Citrus Pathogens: Chemical Analysis of Thymus capitatus Oil and its Effect in Subatmospheric Pressure Conditions

2001 ◽  
Vol 64 (7) ◽  
pp. 1025-1029 ◽  
Author(s):  
GIOVANNI ARRAS ◽  
MARIANNA USAI
Keyword(s):  
Electron Microscope ◽  
Medicinal Plants ◽  
Chemical Analysis ◽  
Essential Oils ◽  
Atmospheric Pressure ◽  
The Other ◽  
Penicillium Italicum ◽  
Thymus Capitatus ◽  
Scanning Electron

The fungitoxic activity against Penicillium digitatum, Penicillium italicum, Botrytis cinerea, and Alternaria citri of 12 essential oils (EOs) distilled from medicinal plants is reported. The results of the in vitro trials show strong fungitoxic activity of Thymus capitatus (L.) Hofmgg EOs, which inhibited the growth of the four fungi at a concentration of 250 ppm (vol/vol). The other 11 essences reduced the development of the fungi from 95 to 9% at 250 ppm (vol/vol). The fungitoxic activity of T. capitatus EOs (75, 150, and 250 ppm) on healthy orange fruits, inoculated with P. digitatum (108 conidia ml−1) by spraying and placed in 10-liter desiccators, was weak at atmospheric pressure (3 to 10% inhibition at all three concentrations), while in vacuum conditions (0.5 bar), conidial mortality on the exocarp was high (90 to 97% at all three concentrations).These data proved not to be statistically different from treatments with thiabendazole-TBZ (2,000 ppm). Scanning electron microscope observations showed that T. capitatus EO vapors altered the morphology of P. digitatum hyphae and conidia. The gas-chromatographic analyses of thyme EO indicated that carvacrol was present at 81 to 83%, p-cymene at 4.5 to 5%, γ-terpinene at 2.6 to 3.3%, caryophyllene at 1.5 to 1.6%, β-myrcene at 1.6%, and linalool at 1.1 to 1.2%. Carvacrol proved to be the most important fungitoxic compound among the thyme EO constituents, but, unlike thyme EO, it caused alterations to the fruit at the concentration of 75 ppm.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

Sign in / Sign up

Export Citation Format

Share Document