scholarly journals Characterization of the purified Chlamydomonas minus agglutinin.

1985 ◽  
Vol 101 (3) ◽  
pp. 1144-1152 ◽  
Author(s):  
P Collin-Osdoby ◽  
W S Adair
Keyword(s):  
Molecular Weight ◽  
Apparent Molecular Weight ◽  
Agarose Beads ◽  
Sds Page ◽  
Sexual Agglutinins ◽  
Molecular Morphology ◽  
High Degree

Chlamydomonas flagellar sexual agglutinins are responsible for the adhesion of opposite mating-type (plus and minus) gametes during the first stages of mating. Purification and partial characterization of the plus agglutinin was previously reported (Adair, W. S., C. J. Hwang, and U. W. Goodenough, 1983, Cell, 33:183-193). Here we characterize the purified minus molecule. We show it to be a high molecular weight, hydroxyproline-rich glycoprotein that migrates in the 3% stacking region of an SDS-polyacrylamide gel and is absent from two nonagglutinating minus mutants. Plus and minus agglutinins are remarkably similar, although nonidentical, in amino acid composition, molecular morphology, and reactivity in vivo and in vitro with monoclonal antibodies raised against the plus agglutinin. Moreover, the adhesiveness of both plus and minus agglutinins, when coupled to agarose beads, is abolished by thermolysin, trypsin, periodate, alkaline borohydride, reducing agents, or heat, but unaffected by exo- or endoglycosidases. The minus agglutinin, however, migrates just ahead of the plus molecule on SDS PAGE, is excluded from an anion-exchange (Mono Q) column, elutes earlier during hydrophobic interaction (Bio-gel TSK Phenyl 5PW) chromatography, and is sensitive to chymotrypsin digestion (unlike the plus agglutinin); therefore, it differs from the plus agglutinin in apparent molecular weight, net charge, relative hydrophobicity and proteolytic susceptibility. Nevertheless, our results generally demonstrate a high degree of homology between these complementary cell-cell recognition/adhesion molecules, which suggests that they are specified by genes that have a common evolutionary origin.

Processing of the precursor to a chloroplast ribosomal protein made in the cytosol occurs in two steps, one of which depends on a protein made in the chloroplast

1985 ◽  
Vol 5 (5) ◽  
pp. 1093-1099
Author(s):  
R J Schmidt ◽  
N W Gillham ◽  
J E Boynton
Keyword(s):  
Molecular Weight ◽  
Protein Synthesis ◽  
Ribosomal Protein ◽  
Apparent Molecular Weight ◽  
Protein L ◽  
Mature Form ◽  
Chloroplast Protein Synthesis ◽  
Made In

In pulse-chase experiments in which log-phase cells of Chlamydomonas reinhardtii were labeled in vivo for 5 min with H2(35)SO4, fluorographs of immunoprecipitates from whole cell extracts revealed that chloroplast ribosomal proteins L-2, L-6, L-21, and L-29, which are made in the cytosol and imported, appeared in their mature forms. However, in the case of chloroplast ribosomal protein L-18, which is also made in the cytoplasm and imported, a prominent precursor with an apparent molecular weight of 17,000 was found at the end of a 5-min pulse. This precursor was processed to its mature size (apparent molecular weight of 15,500) within the first 5 min of the subsequent chase. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the precursor to L-18 formed in vivo was 1.5 kilodaltons smaller than the primary product detected in translations of Chlamydomonas polyadenylated RNA in vitro. Upon a 10-min incubation with a postribosomal supernatant from Chlamydomonas, the 18,500-dalton precursor detected in vitro could be partially converted into a polypeptide that comigrated with the 17,000-dalton precursor detected in extracts of cells labeled in vivo. Under conditions in which the total amounts of chloroplast proteins had been reduced and cells were made to synthesize ribosomes rapidly, the apparent half-life of the 17,000-dalton precursor was extended over that seen in log-phase cells. When chloroplast protein synthesis was inhibited with lincomycin for 3 h before labeling under these conditions, the 17,000-dalton L-18 precursor but not the mature form was found, and the precursor was slowly degraded during a 60-min chase. When cells were placed in the dark for 3 h before labeling, processing of this precursor to the mature form appeared unaffected, but the chloroplast-synthesized ribosomal protein L-26 was detected, indicating that chloroplast protein synthesis was still occurring. We interpret these results to indicate that the maturation of protein L-18 in vivo involves at least two processing steps, one of which depends on a protein made on chloroplast ribosomes.

scholarly journals Isolation and characterization of adrenocortical progenitors involved in the adaptation to stress

2018 ◽  
Vol 115 (51) ◽  
pp. 12997-13002 ◽  
Author(s):  
Charlotte Steenblock ◽  
Maria F. Rubin de Celis ◽  
Luis F. Delgadillo Silva ◽  
Verena Pawolski ◽  
Ana Brennand ◽  
...  
Keyword(s):  
Lineage Tracing ◽  
Differentiated Cells ◽  
Isolation And Characterization ◽  
Proliferation And Differentiation ◽  
Response To Stress ◽  
Steroidogenic Cells ◽  
High Degree

The adrenal gland is a master regulator of the human body during response to stress. This organ shows constant replacement of senescent cells by newly differentiated cells. A high degree of plasticity is critical to sustain homeostasis under different physiological demands. This is achieved in part through proliferation and differentiation of adult adrenal progenitors. Here, we report the isolation and characterization of a Nestin+ population of adrenocortical progenitors located under the adrenal capsule and scattered throughout the cortex. These cells are interconnected with progenitors in the medulla. In vivo lineage tracing revealed that, under basal conditions, this population is noncommitted and slowly migrates centripetally. Under stress, this migration is greatly enhanced, and the cells differentiate into steroidogenic cells. Nestin+ cells cultured in vitro also show multipotency, as they differentiate into mineralocorticoid and glucocorticoid-producing cells, which can be further influenced by the exposure to Angiotensin II, adrenocorticotropic hormone, and the agonist of luteinizing hormone-releasing hormone, triptorelin. Taken together, Nestin+ cells in the adult adrenal cortex exhibit the features of adrenocortical progenitor cells. Our study provides evidence for a role of Nestin+ cells in organ homeostasis and emphasizes their role under stress. This cell population might be a potential source of cell replacement for the treatment of adrenal insufficiency.

scholarly journals Isolation and Characterization of Two Proteins fromMoraxella catarrhalis That Bear a Common Epitope

1998 ◽  
Vol 66 (9) ◽  
pp. 4374-4381 ◽  
Author(s):  
John C. McMichael ◽  
Michael J. Fiske ◽  
Ross A. Fredenburg ◽  
Deb N. Chakravarti ◽  
Karl R. VanDerMeid ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Bacterial Attachment ◽  
Vaccine Candidates ◽  
Isolation And Characterization ◽  
Sds Page

ABSTRACT The UspA1 and UspA2 proteins of Moraxella catarrhalisare potential vaccine candidates for preventing disease caused by this organism. We have characterized both proteins and evaluated their vaccine potential using both in vitro and in vivo assays. Both proteins were purified from the O35E isolate by Triton X-100 extraction, followed by ion-exchange and hydroxyapatite chromatography. Analysis of the sequences of internal peptides, prepared by enzymatic and chemical cleavage of the proteins, revealed that UspA1 and UspA2 exhibited distinct structural differences but shared a common sequence including an epitope recognized by the monoclonal antibody 17C7. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), purified UspA1 exhibited a molecular weight of approximately 350,000 when unheated and a molecular weight of 100,000 after being heated for 10 min at 100°C. In contrast, purified UspA2 exhibited an apparent molecular weight of 240,000 by SDS-PAGE that did not change with the length of time of heating. Their sizes as determined by gel filtration were 1,150,000 and 830,000 for UspA1 and UspA2, respectively. Preliminary results indicate the proteins have separate functions in bacterial pathogenesis. Purified UspA1 was found to bind HEp-2 cells, and sera against UspA1, but not against UspA2, blocked binding of the O35E isolate to the HEp-2 cells. UspA1 also bound fibronectin and appears to have a role in bacterial attachment. Purified UspA2, however, did not bind fibronectin but had an affinity for vitronectin. Both proteins elicited bactericidal antibodies in mice to homologous and heterologous disease isolates. Finally, mice immunized with each of the proteins, followed by pulmonary challenge with either the homologous or a heterologous isolate, cleared the bacteria more rapidly than mock-immunized mice. These results suggest that UspA1 and UspA2 serve different virulence functions and that both are promising vaccine candidates.

Characterization Of The ADP-Induced Fibrinogen Btnd1Ng Sites On Human Platelets Using Photoaffinity Techniques: Some Preliminary Findings

1981 ◽  
Author(s):  
Ellinor I Peerschke ◽  
Mariorie B Zucker ◽  
Avner Rotman
Keyword(s):  
Molecular Weight ◽  
Apparent Molecular Weight ◽  
Human Platelets ◽  
Platelet Membrane ◽  
Membrane Fragment ◽  
Fibrinogen Receptor ◽  
Congenital Deficiency ◽  
Sds Page ◽  
Platelet Membrane Receptor

The interaction of fibrinogen with its, platelet membrane receptor was investigated using 125-labeled fibrinogen which was photoaffinity labeled with a light-sensitive azide. This photoreactive material (125I-NPA-fibr) was indistinguishable from unlabeled fibrinogen as well as from iodinated fibrinogen on SDS-PAGE. It bound specifically to platelets stimulated with ADP and was crosslinked to the platelet membrane after exposure to light ( λ >300 nm) for 4 min. No crosslinking was observed in the presence of EDTA or with platelets that failed to aggregate with ADP either due to the congenital deficiency thrombasthenia or following incubation with EDTA for 8 min at 37° , pH 7.8 and recalcification. SDS-PAGE of platelets bearing crosslinked 125I-NPA-fibr revealed a radiolabeled band of about 450,000 daltons in addition to the 340,000 dalton radioactive band of fibrinogen, suggesting that fibrinogen had been covalently bound to a platelet membrane component with an intact apparent molecular weight of approximately 110,000 daltons. Following reduction, an extra radioactive band was noted at 80,000 daltons. As the A∝-chains of fibrinogen were too weakly labeled to be detected by autoradiography, this indicated that either the Bβ or γchain of fibrinogen was attached to a 25,000-35,000 molecular weight platelet membrane fragment. We conclude that the additional radioactive bands observed after electrophoresis of platelets bearing specifically bound-photoaffinity labeled 125I-fibrinogen most likely represent the binding of the B β or γ chains of fibrinogen to the platelet fibrinogen receptor which may be GPIIb.

Isolation and Partial Characterization of Equine Antithrombin III.

1979 ◽  
Author(s):  
D.W. Estry ◽  
T.G. Bell ◽  
G.H. Tishkoff ◽  
J.C. Mattson ◽  
S.C. Estry
Keyword(s):  
Molecular Weight ◽  
Antithrombin Iii ◽  
Stable Complex ◽  
Sds Page ◽  
At Iii ◽  
Human Thrombin ◽  
Horse Plasma ◽  
Stoichiometric Complex

A protein analogous to human antithrombin III was isolated from fresh horse plasma. The procedure for purification was a modification of Thaler and Schmer’s two-step isolation procedure. The horse protein was homogeneous on 7.5% SDS-PAGE gels and had a molecular weight of 62,000 to 64,000 daltons in both reducing and non-reducing systems (human; 62,300). Rabbit anti-human antithrombin III was used to demonstrate a line of partial identity by Immunoelectrophoresis between the horse and human protein. The horse protein rapidly neutralizes human thrombin (34,000 daltons) and the reaction appears to be greatly potentiated by heparin. In order to establish the formation of 1:1 covalent stoichiometric complex between horse AT III and thrombin (IIa), time studies were run in the presence and absence of heparin. AT III (62,000) at 15 seconds, 2, 5, 10 and 60 minutes formed a stable complex with thrombin (32,000) having a molecular weight of 86,000 daltons. Additional bands developing with time are due to the autolytic capabilities of the uncomplexed IIa. The major autolytic band had a molecular weight of 70,000 daltons. Addition of heparin potentiated the interaction although it did not change the stoichio-metry of the complexes formed. The data accumulated to date demonstrates the similarities between the human and horse protein and the possibilities of using the horse as a model system for the evaluation of AT III replacement therapy in vivo.

scholarly journals Processing of the precursor to a chloroplast ribosomal protein made in the cytosol occurs in two steps, one of which depends on a protein made in the chloroplast.

1985 ◽  
Vol 5 (5) ◽  
pp. 1093-1099 ◽  
Author(s):  
R J Schmidt ◽  
N W Gillham ◽  
J E Boynton
Keyword(s):  
Molecular Weight ◽  
Protein Synthesis ◽  
Ribosomal Protein ◽  
Apparent Molecular Weight ◽  
Protein L ◽  
Mature Form ◽  
Chloroplast Protein Synthesis ◽  
Made In

In pulse-chase experiments in which log-phase cells of Chlamydomonas reinhardtii were labeled in vivo for 5 min with H2(35)SO4, fluorographs of immunoprecipitates from whole cell extracts revealed that chloroplast ribosomal proteins L-2, L-6, L-21, and L-29, which are made in the cytosol and imported, appeared in their mature forms. However, in the case of chloroplast ribosomal protein L-18, which is also made in the cytoplasm and imported, a prominent precursor with an apparent molecular weight of 17,000 was found at the end of a 5-min pulse. This precursor was processed to its mature size (apparent molecular weight of 15,500) within the first 5 min of the subsequent chase. As determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the precursor to L-18 formed in vivo was 1.5 kilodaltons smaller than the primary product detected in translations of Chlamydomonas polyadenylated RNA in vitro. Upon a 10-min incubation with a postribosomal supernatant from Chlamydomonas, the 18,500-dalton precursor detected in vitro could be partially converted into a polypeptide that comigrated with the 17,000-dalton precursor detected in extracts of cells labeled in vivo. Under conditions in which the total amounts of chloroplast proteins had been reduced and cells were made to synthesize ribosomes rapidly, the apparent half-life of the 17,000-dalton precursor was extended over that seen in log-phase cells. When chloroplast protein synthesis was inhibited with lincomycin for 3 h before labeling under these conditions, the 17,000-dalton L-18 precursor but not the mature form was found, and the precursor was slowly degraded during a 60-min chase. When cells were placed in the dark for 3 h before labeling, processing of this precursor to the mature form appeared unaffected, but the chloroplast-synthesized ribosomal protein L-26 was detected, indicating that chloroplast protein synthesis was still occurring. We interpret these results to indicate that the maturation of protein L-18 in vivo involves at least two processing steps, one of which depends on a protein made on chloroplast ribosomes.

Construction and Characterization of a Novel Ribonuclease Immunotoxin Consisting of Two Ranpirnase (Rap) Molecules Fused to an Internalizing Anti-CD74 Humanized IgG4 Antibody.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3289-3289
Author(s):  
Sailaja S. Vanama ◽  
Puja Sapra ◽  
Hans J. Hansen ◽  
Ivan D. Horak ◽  
David M. Goldenberg ◽  
...  
Keyword(s):  
Hodgkin’S Lymphoma ◽  
Xenograft Model ◽  
Hodgkin's Lymphoma ◽  
Light Chains ◽  
Non Hodgkin’S Lymphoma ◽  
Non Hodgkin's Lymphoma ◽  
Sds Page

Abstract Ranpirnase (Rap), isolated from frog (Rana pipiens) oocytes, is a monomeric ribonuclease (MW 11800) that kills cells by degrading t-RNA upon internalization. Previous studies indicated that the cytotoxicity of Rap could be enhanced more than 10,000-fold when the enzyme is chemically conjugated to an internalizing antibody. Here we describe the construction and characterization of 2L-Rap-hLL1-γ4P, composed of two Rap molecules fused to hLL1, an internalizing anti-CD74 humanized monoclonal antibody. To reduce unwanted cytotoxicity, the IgG1 constant region of hLL1 was replaced with an IgG4 that contains a proline mutation in the hinge region. The Rap gene was inserted at the N-terminus of the light chain in the expression vector of hLL1 and expressed in NS0 mouse myeloma cells. The fusion protein was characterized by a variety of techniques, including SE-HPLC, SDS-PAGE, in vitro transcription translation (IVTT) assay using luciferase reporter system, and competition ELISA to measure the binding affinity for CD74. The in vitro potency was determined in non-Hodgkin’s lymphoma (Daudi) and multiple myeloma (MC/CAR) cell lines by MTS tetrazolium dye reduction assay. In vivo pharmacokinetics and biodistribution of radiolabeled 2L-Rap-hLL1- γ4P was compared to radiolabeled hLL1 mAb in naïve mice and in vivo therapeutic efficacy of 2L-Rap-hLL1- γ4P was determined in a xenograft model of Burkitt’s non-Hodgkin’s lymphoma (Daudi). Purified 2L-Rap-hLL1- γ4P was shown to be a single peak by SE-HPLC and its MW determined by MALDI-TOF to be 177,150, which is in agreement with the MW of one IgG (150,000) plus two Rap molecules (24,000). Reducing-SDS-PAGE of 2L-Rap-hLL1- γ4P revealed the presence of 3 bands, one corresponding to the heavy chain and the other two appearing to be derived from the Rap-fused light chains (38,526 and 36,700 by MS). Occurrence of the 2 light chains was shown to be due to glycosylation of Rap at the N69 residue. The binding affinity of 2L-Rap-hLL1- γ4P for CD74 was indistinguishable from that of hLL1. Both 2L-Rap-hLL1- γ4P and hLL1 bound to CD74 with subnanomolar affinity. The EC50 of RNase activity, as measured by the IVTT assay, was 300 pM for 2L-Rap-hLL1- γ4P and 30 pM for recombinant Rap (expressed in E. coil). In in vitro cytotoxicity assays, 2L-Rap-hLL1- γ4P was significantly cytotoxic against Daudi (EC50 280 pM) and the myeloma cell line, MC/CAR (EC50 50 nM). In contrast, free Rap or naked hLL1 did not demonstrate significant cytotoxicity at the concentrations tested. In vivo, the pharmacokinetic profile of 2L-Rap-hLL1- γ4P was almost identical to that of naked hLL1. Both 2L-Rap-hLL1- γ4P and hLL1 showed biphasic clearance from the circulation; the α and β half-life (t1/2) of 2L-Rap-hLL1- γ4P were 5 h and 119 h, respectively, and those of hLL1 were 4 h and 125 h, respectively. In tissue biodistribution studies, no significant difference was observed between 2L-Rap-hLL1- γ4P and hLL1 with regards to normal tissue uptake. Early efficacy results in the Daudi Burkitt’s non-Hodgkin’s lymphoma xenograft model demonstrate that treatment with a single dose of 2L-Rap-hLL1- γ4P as low as 1 μg/mouse significantly improves survival in comparison to untreated control mice (P<0.0001).

scholarly journals MR imaging of model drug distribution in simulated vitreous

2015 ◽  
Vol 1 (1) ◽  
pp. 236-239 ◽  
Author(s):  
Sandra Stein ◽  
Christian Simroth-Loch ◽  
Sönke Langner ◽  
Stefan Hadlich ◽  
Oliver Stachs ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ex Vivo ◽  
Drug Distribution ◽  
Injection Technique ◽  
Innovative Therapy ◽  
Age Related ◽  
The Impact

AbstractThe in vitro and in vivo characterization of intravitreal injections plays an important role in developing innovative therapy approaches. Using the established vitreous model (VM) and eye movement system (EyeMoS) the distribution of contrast agents with different molecular weight was studied in vitro. The impact of the simulated age-related vitreal liquefaction (VL) on drug distribution in VM was examined either with injection through the gel phase or through the liquid phase. For comparison the distribution was studied ex vivo in the porcine vitreous. The studies were performed in a magnetic resonance (MR) scanner. As expected, with increasing molecular weight the diffusion velocity and the visual distribution of the injected substances decreased. Similar drug distribution was observed in VM and in porcine eye. VL causes enhanced convective flow and faster distribution in VM. Confirming the importance of the injection technique in progress of VL, injection through gelatinous phase caused faster distribution into peripheral regions of the VM than following injection through liquefied phase. VM and MR scanner in combination present a new approach for the in vitro characterization of drug release and distribution of intravitreal dosage forms.

scholarly journals Characterization of ornithine decarboxylase of tobacco cells and tomato ovaries.

1982 ◽  
Vol 201 (2) ◽  
pp. 373-376 ◽  
Author(s):  
Y M Heimer ◽  
Y Mizrahi
Keyword(s):  
Molecular Weight ◽  
Ornithine Decarboxylase ◽  
Pyridoxal Phosphate ◽  
Apparent Molecular Weight ◽  
Ph Optimum ◽  
Tobacco Cells ◽  
Thiol Reagent ◽  
Mammalian Origin

Some characteristics of L-ornithine decarboxylase of tomato ovaries and tobacco cells are described. The enzyme has a pH optimum of 8.0. It requires pyridoxal phosphate and thiol reagent (dithiothreitol) for activity. It is specific for L-ornithine and has an apparent Km of 1.4 × 10-4 M. It has an apparent molecular weight of 107000. Putrescine inhibited the activity in vitro. Spermidine and spermine also inhibit the enzyme, but less effectively. It is concluded that the enzyme is similar to that of mammalian origin and likewise fulfils a function related to cell proliferation.

Complexing of Low Mr-Weight Human Urokinase In Rat Serum And Its Degradation Into Fragments Of Very Small Molecular Weight In Vivo But Not In Vitro

1981 ◽  
Author(s):  
Ph Schneider ◽  
M Ruegg ◽  
F Bachmann
Keyword(s):  
Molecular Weight ◽  
Inferior Vena ◽  
Vena Cava ◽  
Albino Rats ◽  
Small Molecular Weight ◽  
Rat Serum ◽  
Blood Samples ◽  
Sds Page

Highly purified lew molecular weight urokinase (LMR-UK), moving on SDS-PAGE (reduced and nan-reduced) as a single band of 32 kdalton, was labelled with 125I by the chlora- mine-T method. 106 cpn of this 125I-LMr-UK (94% TCA preci- pitable) were injected into the inferior vena cava of la- par atomized albino rats, which were maintained at 37°C. Blood samples were collected by cardiac puncture 5, 30 and 90 min respectively after the injection. Serun, obtained from these samples, was fractionated on a Sephadex G-100 column, calibrated with proteins of known Mr. Radioactivity was measured in the collected fractions.In the 5 min sample, the radioactivity was distributed in 2 peaks, corresponding to 32 kdalton and to < 70 kdalton respectively. In the 30 min sample, the distribution was characterized by a diminution of the 32 kdalton peak and the appearance of a third peak corresponding to a Mr of < 4 kdalton. In the 90 min sample, the LMr-UK peak had disappeared almost completely. About 40% of the 125I-activity was present in a skewed high Mr peak with a broad maximum in the 85-100 kdalton region; ≥ 60% of the 125I-activity was recovered in late fractions corresponding to < 4 kdalton. In control experiments, pooled rat serum was incubated in vitro with 125I-LMr-UK for 5, 30 and 90 min respectively and samples were fractionated on the same column. The radioactivity distribution shewed only the 32 and > 70 kdalton peaks, but no < 4 kdalton peak.These results suggest that LMr-UK is complexed to a carrier protein, both in vivo and in vitro, but that it is degraded into small fragments in vivo only. Attempts to characterize the nature of these complexes are in progress.

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