membrane characteristic
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2019 ◽  
Author(s):  
Honoree Fleming

This paper describes the amitotic proliferation of nuclei that fill the envelope of Ishikawa hollow spheroids. The presence of hollow spheroids in malignant ascites fluid has intrigued cancer researchers, but little is understood about how they form. Observations in Ishikawa endometrial cell cultures demonstrate that nuclei filling the spheroid envelope are generated amitotically by the same mechanism responsible for cell formation in domes. Transient structures of aggregated chromatin surrounded by fused giant mitochondria, the initiating structure for dome formation, are also the starting point for the differentiation of unicellular polyploid hollow spheroids. Nuclei from monolayer cells are aggregated in a single enlarged cell where they become surrounding by giant fused mitochondria. A gaseous vacuole forms inside the mitonucleon extending it so that all of the cell material, including nuclei is pressed against the cell membrane. The resulting unicellular hollow spheroid detaches from the colony, capable of migration from the site of its formation. Ultimately, pressure on the aggregated chromatin results in the release of streams of chromatin granules that initially travel as if guided by microtubules through the shell of the hollow spheroid. Granules dissolve into filaments and, as initially described in dome formation, this material self-assembles into clusters of nuclei. Nuclei move out of these clusters into a regular array within the spheroid envelope, with formation of cell membranes as the final step in the creation of multicellular hollow spheroids. The curved membrane characteristic of domes and spheroids, as well as colonies of nuclei produced by amitosis have been identified in tumor tissue that survives chemotherapy, suggesting that amitotic cell proliferation may at least partially explain the population of cancer tumor cells in humans that are resistant to chemotherapy.



2019 ◽  
Author(s):  
Honoree Fleming

This paper describes the amitotic proliferation of nuclei that fill the envelope of Ishikawa hollow spheroids. The presence of hollow spheroids in malignant ascites fluid has intrigued cancer researchers, but little is understood about how they form. Observations in Ishikawa endometrial cell cultures demonstrate that nuclei filling the spheroid envelope are generated amitotically by the same mechanism responsible for cell formation in domes. Transient structures of aggregated chromatin surrounded by fused giant mitochondria, the initiating structure for dome formation, are also the starting point for the differentiation of unicellular polyploid hollow spheroids. Nuclei from monolayer cells are aggregated in a single enlarged cell where they become surrounding by giant fused mitochondria. A gaseous vacuole forms inside the mitonucleon extending it so that all of the cell material, including nuclei is pressed against the cell membrane. The resulting unicellular hollow spheroid detaches from the colony, capable of migration from the site of its formation. Ultimately, pressure on the aggregated chromatin results in the release of streams of chromatin granules that initially travel as if guided by microtubules through the shell of the hollow spheroid. Granules dissolve into filaments and, as initially described in dome formation, this material self-assembles into clusters of nuclei. Nuclei move out of these clusters into a regular array within the spheroid envelope, with formation of cell membranes as the final step in the creation of multicellular hollow spheroids. The curved membrane characteristic of domes and spheroids, as well as colonies of nuclei produced by amitosis have been identified in tumor tissue that survives chemotherapy, suggesting that amitotic cell proliferation may at least partially explain the population of cancer tumor cells in humans that are resistant to chemotherapy.



2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Ni Putu Sri Ayuni ◽  
Ni Wayan Yuningrat ◽  
Ketut Yesi Andriani

Abstrak Sekitar 2-50% dari zat warna azo yang digunakan selama proses pencelupan ini tidak mengikat serat dan langsung dilepaskan ke lingkungan melalui instalasi pengolahan limbah. Hal ini perlu dilakukan pengolahan limbah cair yang mengandung zat warna azo jenis Remazol Black B sebelum dibuang ke lingkungan. Penelitian ini bertujuan untuk mengetahui kondisi optimum membran PEC kitosan-pektin yang dapat digunakan untuk mengadsorpsi zat warna azo jenis Remazol Black B .Untuk memperoleh kondisi optimum akan dilakukan adsorpsi zat warna azo jenis Remazol Black B dengan variasi waktu kontak (5-150 menit), pH (5-9) dan konsentrasi larutan zat warna azo jenis Remazol Black B (5, 10, 15, 20, dan 25 mg/L). Untuk mengetahui karakteristik zat warna jenis Remazol Black B oleh membran PEC kitosan-pektin di analisis dengan persamaan isoterm adsorpsi Langmuir dan isoterm adsorpsi Freundlich sedangkan daya adsorpsi maksimum dari membran PEC kitosan pektin ditentukan dari kurva berdasarkan karakteristik membran yang diperoleh. Hasil penelitian menunjukkan bahwa adsorpsi zat warna azo jenis Remazol Black B terjadi pada kondisi optimum dengan pH 5, waktu 120 menit dan konsentrasi larutan zat warna azo jenis Remazol Black B 10 mg/L (62,75 %). Pola adsorpsi mengikuti pola adsorpsi isoterm Freundlich dengan daya adsorpsi maksimum 0,02 (mg/g). Untuk efisiensi desorpsi maksimal diperoleh pada larutan NaCl 1 M (11,17 %) Kata Kunci: adsorpsi, membran polielektrolit kitosan pektin, Remazol Black B Abstract Azo dyes produced approximately 2-50% from dying process were thrown through effluent to the environment without any treatment. The objective of this research were to know the optimum condition of PEC chitosan pectin membrane using to adsorp Remazol Black B with various contact time (5-150 min), pH (5-9) and Remazol Black B concentration (5, 10, 15, 20, dan 25 mg/L). Adsorption charactheristic of Remazol Black B by PEC chitosan pectin membrane were determined by Langmuir and Freundlich isotherm equation. Maximum capacity adsorption was determined by the graph of membrane characteristic. The results show that optimum condition of Remazol Black B adsorption by PEC chitosan pectin membrane at pH 5, 10 mg/L remazol black B for 120 minutes (62,75 %). The adsorption pattern is Freundlich isoterm with maximum capacity 0,02 (mg/g).Maximal Desorption efisiency at NaCl 1 M (11,17 %) Keywords : adsorption, PEC chitosan pectin membrane, Remazol Black B







1994 ◽  
Vol 49 (9-10) ◽  
pp. 615-618
Author(s):  
J. Benavente ◽  
A. Muñoz ◽  
A. Heredia

Abstract Membrane potential and electrical resistance for two isolated fruit cuticular membranes (tomato and pepper cuticles) were measured for different NaCl solutions (10-3 ᴍ < C < 5 × 10-2 ᴍ). From these experimental results some membrane characteristic parameters were obtained such as cation transport number, t+, which represents the fraction of the electric current transported by the cation, l+ , with respect to the total current, lT (t+ = l+/lT) , and ionic permeabilities, P+ and P-, for both membranes. Concentration dependence of these parameters was also considered. A comparative study between both types of fruit cuticles is also made. It was found that cation transport number, ionic permeabilities and electrical resistances are quite similar for both membranes.



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