scholarly journals Dynein-like Mg2+-ATPase in mitotic spindles isolated from sea urchin embryos (Strongylocentrotus droebachiensis).

1980 ◽  
Vol 86 (3) ◽  
pp. 738-745 ◽  
Author(s):  
M M Pratt ◽  
T Otter ◽  
E D Salmon

Two distinctly different ATPases have been reported to be endogenous to the mitotic apparatus: a Mg2+-ATPase resembling axonemal dynein, and a Ca2+-ATPase postulated to be bound in membranes. To examine the nature of the Mg2+-ATPase, we isolated membrane-free mitotic spindles from Stronglylocentrotus droebachiensis embryos by rapidly lysing these in a calcium-chelating, low-ionic-strength buffer (5 mM EGTA, 0.5 mM MgCl2, 10 mM PIPES, pH 6.8) that contained 1% Nonidet P-40. The fibrous isolated mitotic spindles closely resembled spindles in living cells, both in general morphology and in birefringence. In electron micrographs, the spindles were composed primarily of microtubules, free from membranes and highly extracted of intermicrotubular cytoplasmic ground substance. As analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), the pelleted spindles contain 18% tubulin, variable amounts of actin (2-8%), and an unidentified protein of 55 kdaltons in a constant weight ratio to tubulin (1:2.5). The isolated spindles also contained two polypeptides, larger than 300 kdaltons, that comigrated with egg dynein polypeptides, and ATPase activity (0.02 mumol Pi/mg . min) that closely resembled both flagellar and egg dynein. The spindle Mg2+-ATPase showed a ratio of Ca2+-/Mg2+-ATPase = 0.85, had minimal activity in KCl and EDTA, and cleaved GTP at 35% of the rate of ATP. The Mg2+-ATPase was insensitive to ouabain or oligomycin. The spindle Mg2+-ATPase was inhibited by sodium vanadate but, like egg dynein, was less sensitive to vanadate than flagellar dynein. The spindle Mg2+-ATPase does not resemble the mitotic Ca2+-ATPase described by others. We propose that the spindle Mg2+-ATPase is egg dynein. Bound carbohydrate on the two high-molecular-weight polypeptides of both egg dynein and the spindle enzyme suggest that these proteins may normally associate with membranes in the living cell.

1984 ◽  
Vol 30 (7) ◽  
pp. 905-915
Author(s):  
M. Egídia Carvalho ◽  
M. Helena Gonçalves ◽  
M. T. Silva

The lytic effect of lysozyme on Streptococcus faecalis ATCC 9790 was studied by spectrophotometry and electron microscopy and it was found to be highly dependent on the ionic strength of the suspending media and on the ratio lysozyme to bacterial cell mass. When 7.2 × 108 bacteria/mL are exposed to 0.4 mg/mL of lysozyme in media with low ionic strength, the enzyme is bound in great amounts, as deduced from protein determinations and sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS–PAGE); the binding prevents bacteriolysis in spite of the removal of the cell wall. Extensive lysis of S. faecalis could be obtained by reducing the ratio of lysozyme to bacterial cell mass. Stabilization of S. faecalis by lysozyme was also observed when exponential phase cells incubated under conditions that promote spontaneous autolysis (incubation in 0.05 M tris(hydroxymethyl)aminomethane buffer, pH 8.0, ionic strength = 0.01675) do not lyse and do not leak material which absorbs at 260 nm when lysozyme was present at the highest concentration.


1980 ◽  
Vol 86 (2) ◽  
pp. 355-365 ◽  
Author(s):  
E D Salmon ◽  
R R Segall

We isolated calcium-labile mitotic spindles from eggs of the sea urchin Lytechinus variegatus, using a low ionic strength, EGTA lysis buffer that contined 5.0 mM EGTA, 0.5 mM MgCl2, 10-50 mM PIPES, pH 6.8, with 1% Nonidet P-40 (detergent) and 20-25% glycerol. Isolated spindles were stored in EGTA buffer with 50% glycerol for 5-6 wk without deterioration. The isolated spindles were composed primarily of microtubules with the chromosomes attached. No membranes were seen. Isolated spindles, perfused with EGTA buffer to remove the detergent and glycerol, had essentially the same birefringent retardation (BR) as spindles in vivo at the same mitotic stage. Even in the absence of glycerol and exogenous tubulin, the isolated spindles were relatively stable in the EGTA buffer: BR decayed slowly to about half the initial value within 30-45 min. However, both the rate and extent of BR decay increased with concentrations of Ca2+ above 0.2-0.5 muM as assayed using Ca-EGTA buffers (0.2 mM EGTA, 0.5 mM MgCl2, 50 mM PIPES, pH 6.8, plus various amounts of CaCl2). Microtubules depolymerized almost completely in < 6 min at Ca2+ concentrations of 2 muM and within several seconds at 10 muM Ca2+. Of several divalent cations tested, only Sr2+ caused comparable changes in BR. The absence of membranes in the isolated spindles appeared to be associated with a lack of calcium-sequestering ability. Our results suggest that calcium ions play an important role in the depolymerization of spindle microtubules and that membrane components may function within the mitotic apparatus of living cells to sequester and release calcium ions during mitosis.


Author(s):  
K.R. Porter

Most types of cells are known from their structure and overall form to possess a characteristic organization. In some instances this is evident in the non-random disposition of organelles and such system subunits as cisternae of the endoplasmic reticulum or the Golgi complex. In others it appears in the distribution and orientation of cytoplasmic fibrils. And in yet others the organization finds expression in the non-random distribution and orientation of microtubules, especially as found in highly anisometric cells and cell processes. The impression is unavoidable that in none of these cases is the organization achieved without the involvement of the cytoplasmic ground substance (CGS) or matrix. This impression is based on the fact that a matrix is present and that in all instances these formed structures, whether membranelimited or filamentous, are suspended in it. In some well-known instances, as in arrays of microtubules which make up axonemes and axostyles, the matrix resolves itself into bridges (and spokes) between the microtubules, bridges which are in some cases very regularly disposed and uniform in size (Mcintosh, 1973; Bloodgood and Miller, 1974; Warner and Satir, 1974).


1992 ◽  
Vol 68 (05) ◽  
pp. 534-538 ◽  
Author(s):  
Nobuhiko Yoshida ◽  
Shingi Imaoka ◽  
Hajime Hirata ◽  
Michio Matsuda ◽  
Shinji Asakura

SummaryCongenitally abnormal fibrinogen Osaka III with the replacement of γ Arg-275 by His was found in a 38-year-old female with no bleeding or thrombotic tendency. Release of fibrinopeptide(s) by thrombin or reptilase was normal, but her thrombin or reptilase time in the absence of calcium was markedly prolonged and the polymerization of preformed fibrin monomer which was prepared by the treatment of fibrinogen with thrombin or reptilase was also markedly defective. Propositus' fibrinogen had normal crosslinking abilities of α- and γ-chains. Analysis of fibrinogen chains on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the system of Laemmli only revealed the presence of abnormal γ-chain with an apparently higher molecular weight, the presence of which was more clearly detected with SDS-PAGE of fibrin monomer obtained by thrombin treatment. Purified fragment D1 of fibrinogen Osaka III also seemed to contain an apparently higher molecular weight fragment D1 γ remnant on Laemmli gels, which was digested faster than the normal control by plasmin in the presence of [ethy-lenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA).


1994 ◽  
Vol 72 (06) ◽  
pp. 906-911 ◽  
Author(s):  
D C Rijken ◽  
E Groeneveld ◽  
M M Barrett-Bergshoeff

SummaryBM 06.022 is a non-glycosylated mutant of human tissue-type plasminogen activator (t-PA) comprising only the kringle-2 and proteinase domains. The in vivo half-life of BM 06.022 antigen is 4- to 5-fold longer than that of t-PA antigen. The in vitro half-life of the activity of BM 06.022 at therapeutic concentrations in plasma is shorter than that of t-PA. In this study the inactivation of BM 06.022 in plasma was further investigated.Varying concentrations of BM 06.022 were incubated in plasma for 0-150 min. Activity assays on serial samples showed a dose-dependent decline of BM 06.022 activity with a half-life from 72 min at 0.3 μg/ml to 38 min at 10 μg/ml. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by fibrin autography showed the generation of several BM 06.022-complexes. These complexes could be completely precipitated with antibodies against Cl-inactivator, α2-antiplasmin and α1-antitrypsin.During the incubation of BM 06.022 in plasma, plasmin was generated dose-dependently as revealed by varying degrees of a2-anti-plasmin consumption and fibrinogen degradation. SDS-PAGE and immunoblotting showed that single-chain BM 06.022 was rapidly (i. e. within 45 min) converted into its two-chain form at concentrations of 5 μg/ml BM 06.022 and higher.In conclusion, BM 06.022 at therapeutic concentrations in plasma was inactivated by Cl-inactivator, a2-antiplasmin and a j-antitrypsin. The half-life of the activity decreased at increasing BM 06.022 concentrations, probably as a result of the generation of two-chain BM 06.022 which may be inactivated faster than the single-chain form.


2018 ◽  
Vol 26 (2) ◽  
pp. 058
Author(s):  
Anna P. Roswiem ◽  
Triayu Septiani

<em>Bahan<strong> </strong>baku untuk membuat baso adalah daging hewan, pada umumnya dari daging sapi, ayam, ikan dan babi. Di beberapa daerah di Indonesia terjadi kasus baso tikus. Tujuan penelitian ini adalah menguji ada tidaknya kandungan daging tikus pada produk baso yang dijual di pasar Cempaka Putih-Kecamatan Kramat Jakarta Pusat dan di pedagang baso atau mie baso di sekitar kampus Universitas YARSI Jakarta. Daging adalah protein salah satu metode untuk mengidentifikasi protein adalah metode Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE).<strong> </strong>Hasil penelitian menunjukkan bahwa dari 6 sampel baso terindikasi ada 2 sampel baso dengan nomor 1 dan 5 yang dibuat dari campuran daging sapi dan tikus; ada 1 sampel baso dengan nomor 6 yang terbuat dari daging tikus; dan 2 sampel baso dengan nomor 2 dan 3 yang terbuat dari campuran sapi  dan babi, dan hanya 1 sampel baso dengan nomor sampel 4 yang benar-benar terbuat dari daging sapi.</em>


2020 ◽  
Vol 20 (8) ◽  
pp. 970-981
Author(s):  
Hamed A. Ghramh ◽  
Essam H. Ibrahim ◽  
Mona Kilnay

Background: Juniperus procera and Majra honey are well-known as a folk medicine in many countries. Objectives: This work aimed to study the immunomodulatory effects after mixing Majra honey, J. procera water leaves extract and silver Nanoparticles (AgNPs) on immune or cancer cells. Methods: Juniperus procera water leaves extract and 20% Majra honey were prepared. Both the extract and honey were used separately to synthesize AgNPs. AgNPs were characterized using UV/Vis spectrophotometry and electron microscopy. Bioactive molecules in honey and the extract were explored using Fourier Transform Infrared (FT-IR) spectroscopy. Protein profile of honey was explored using Sodium Dodecyl Sulfate- Polyacrylamide Gel Electrophoresis (SDS-PAGE) and honey sugar content was determined using High- Performance Liquid Chromatography (HPLC). Biological activities of honey and the extract were tested. Results: The results demonstrated the ability of the extract/honey to produce AgNPs in a spherical shape. The extract/honey contained many functional groups. SDS-PAGE of Majra honey showed many protein bands. HPLC revealed honey is of good quality and no external additives are added to it. The extract and extract+ AgNPs inhibited the growth of normal rat splenic cells while honey stimulated it. The extract+honey turned stimulatory to the splenic cells’ growth and significantly diminished the inhibitory potential of the extract containing AgNPs. Both the extract and honey have antimicrobial activities, this potential increased in the presence of AgNPs. Honey and Honey+AgNPs inhibited HepG2 cancer cell proliferation while Hela cell growth inhibited only with honey+AgNPs. Conclusion: Both honey and the extract have antibacterial and immunomodulatory potentials as well as the power to produce AgNPs. Majra honey alone showed anticancer activity against HepGe2 cells, but not against Hela cells, and when contained AgNPs had anticancer activity on both cell lines. Mixing of Majra honey with J. procera extract showed characterized immunomodulatory potentials that can be described as immunostimulant.


Author(s):  
Preeti Anand ◽  
Jay Prakash Pandey ◽  
Dev Mani Pandey

Abstract Background Cocoonase is a proteolytic enzyme that helps in dissolving the silk cocoon shell and exit of silk moth. Chemicals like anhydrous Na2CO3, Marseille soap, soda, ethylene diamine and tartaric acid-based degumming of silk cocoon shell have been in practice. During this process, solubility of sericin protein increased resulting in the release of sericin from the fibroin protein of the silk. However, this process diminishes natural color and softness of the silk. Cocoonase enzyme digests the sericin protein of silk at the anterior portion of the cocoon without disturbing the silk fibroin. However, no thorough characterization of cocoonase and sericin protein as well as imaging analysis of chemical- and enzyme-treated silk sheets has been carried out so far. Therefore, present study aimed for detailed characterization of cocoonase and sericin proteins, phylogenetic analysis, secondary and tertiary structure prediction, and computational validation as well as their interaction with other proteins. Further, identification of tasar silkworm (Antheraea mylitta) pupa stage for cocoonase collection, its purification and effect on silk sheet degumming, scanning electron microscope (SEM)-based comparison of chemical- and enzyme-treated cocoon sheets, and its optical coherence tomography (OCT)-based imaging analysis have been investigated. Various computational tools like Molecular Evolutionary Genetics Analysis (MEGA) X and Figtree, Iterative Threading Assembly Refinement (I-TASSER), self-optimized predicted method with alignment (SOPMA), PROCHECK, University of California, San Francisco (UCSF) Chimera, and Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) were used for characterization of cocoonase and sericin proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), protein purification using Sephadex G 25-column, degumming of cocoon sheet using cocoonase enzyme and chemical Na2CO3, and SEM and OCT analysis of degummed cocoon sheet were performed. Results Predicted normalized B-factors of cocoonase and sericin with respect to α and β regions showed that these regions are structurally more stable in cocoonase while less stable in sericin. Conserved domain analysis revealed that B. mori cocoonase contains a trypsin-like serine protease with active site range 45 to 180 query sequences while substrate binding site from 175 to 200 query sequences. SDS-PAGE analysis of cocoonase indicated its molecular weight of 25–26 kDa. Na2CO3 treatment showed more degumming effect (i.e., cocoon sheet weight loss) as compared to degumming with cocoonase. However, cocoonase-treated silk cocoon sheet holds the natural color of tasar silk, smoothness, and luster compared with the cocoon sheet treated with Na2CO3. SEM-based analysis showed the noticeable variation on the surface of silk fiber treated with cocoonase and Na2CO3. OCT analysis also exemplified the variations in the cross-sectional view of the cocoonase and Na2CO3-treated silk sheets. Conclusions Present study enlightens on the detailed characteristics of cocoonase and sericin proteins, comparative degumming activity, and image analysis of cocoonase enzyme and Na2CO3 chemical-treated silk sheets. Obtained findings illustrated about use of cocoonase enzyme in the degumming of silk cocoon at larger scale that will be a boon to the silk industry.


2003 ◽  
Vol 49 (10) ◽  
pp. 625-632 ◽  
Author(s):  
Claudia Masini d'Avila-Levy ◽  
Rodrigo F Souza ◽  
Rosana C Gomes ◽  
Alane B Vermelho ◽  
Marta H Branquinha

Actively motile cells from a cured strain of Crithidia deanei released proteins in phosphate buffer (pH 7.4). The molecular mass of the released polypeptides, which included some proteinases, ranged from 19 to 116 kDa. One of the major protein bands was purified to homogeneity by a combination of anion-exchange and gel filtration chromatographs. The apparent molecular mass of this protein was estimated to be 62 kDa by sodium dodecyl sulfate – polyacrylamide gel electrophoresis (SDS–PAGE). The incorporation of gelatin into SDS–PAGE showed that the purified protein presented proteolytic activity in a position corresponding to a molecular mass of 60 kDa. The enzyme was optimally active at 37 °C and pH 6.0 and showed 25% of residual activity at 28 °C for 30 min. The proteinase was inhibited by 1,10-phenanthroline and EDTA, showing that it belonged to the metalloproteinase class. A polyclonal antibody to the leishmanial gp63 reacted strongly with the released C. deanei protease. After Triton X-114 extraction, an enzyme similar to the purified metalloproteinase was detected in aqueous and detergent-rich phases. The detection of an extracellular metalloproteinase produced by C. deanei and some other Crithidia species suggests a potential role of this released enzyme in substrate degradation that may be relevant to the survival of trypanosomatids in the host.Key words: endosymbiont, trypanosomatid, extracellular, proteinase.


2000 ◽  
Vol 83 (01) ◽  
pp. 60-64 ◽  
Author(s):  
Seiji Miyamoto ◽  
Atsushi Iwasa ◽  
Masao Ishii ◽  
Kenji Okajima ◽  
Yu-ichi Kamikubo

SummaryWe recently observed a patient with acquired inhibitor-induced F.VII deficiency whose plasma level of F.VII was < 1.0%. However, the biochemical nature of the inhibitor has not yet been clarified. In the present study, we purified the F.VII inhibitor from the patient’s plasma by using activated F.VII (F.VIIa)-conjugated gel and characterized the inhibitor. The results showed that the inhibitor comprised two kinds of antibodies: one was eluted with EDTA (antibody 1) and the other with glycine-HCl buffer (pH 2.3) (antibody 2) from the F.VIIa affinity gel. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting analysis of these inhibitors demonstrated that both antibodies had features of immunoglobulin G1 (IgG1) with κ and λ-light chains. Antibody 1 bound to the immobilized F.VIIa with a high affinity in the presence of calcium ion, while antibody 2 bound to the F.VIIa very weakly and the binding was independent of calcium ion. Immunoblotting analysis demonstrated that antibody 1 bound to the light chain of F.VIIa after reduction with 2-mercaptoethanol, while it did not react with either the γ carboxyglutamic acid (Gla)-domainless light chain of F.VIIa or the heavy chain with the protease domain. Antibody 1 markedly inhibited the activity of tissue factor-F.VIIa complex. Based on these observations, it is suggested that F.VIIa autoantibody (antibody 1) recognizes the calcium-dependent conformation within or near the Gla domain and inhibits F.VIIa activity by interacting with the light chain.


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