NEW BACTERIAL AGGREGATE-FORMING PRODUCER OF POLY-3-HYDROXYBUTYRATE

2020 ◽  
pp. 422-423
Author(s):  
A. Pshenichnikova
Keyword(s):  
Suspension Culture ◽  
Cell Aggregation ◽  
Methylotrophic Bacterium ◽  
Carotenoid Pigment ◽  
Cell Aggregates ◽  
Bacterial Aggregate

The growth and accumulation of carotenoid pigment and poly-3-hydroxybutyrate by a new strain of pink-colored facultative methylotrophic bacterium Methylorubrum extorquens LP in suspension culture and in cell aggregates were studied. The parameters that promote cell aggregation and the formation of poly-3-hydroxybutyrate have been determined.

Effects on Erythrocyte Aggregation and Blood Coagulation from Iohexol Solutions with and without Sodium Chloride

1995 ◽  
Vol 36 (2) ◽  
pp. 204-209
Author(s):  
C.-M. Chai ◽  
T. Almén ◽  
P. Aspelin ◽  
L. Bååth
Keyword(s):  
Sodium Chloride ◽  
Blood Coagulation ◽  
Glucose Solution ◽  
Cell Aggregation ◽  
Test Solution ◽  
Erythrocyte Aggregation ◽  
Cell Aggregates ◽  
Red Cell ◽  
Red Blood Cell Aggregation ◽  
Osmotic Effects

Solutions of the nonionic monomeric contrast medium iohexol (300 mg I/ml) with and without added NaCl were investigated for effects on red blood cell aggregation and blood coagulation. Three volumes of a test solution were mixed in test tubes with one volume of human blood. During 30 min samples of the mixture were taken for investigation. Six test solutions were used: 1) iohexol, 2) iohexol+glucose 280 mM, 3) iohexol+NaCl 150 mM, 4) glucose 280 mM, 5) glucose 140 mM+NaCl 75 mM, 6) NaCl 150 mM. Test solutions with NaCl caused no aggregation. Test solutions without NaCl always caused macroscopic red cell aggregates. These aggregates always disappeared when saline was added to the sample. The macroscopic red cell aggregates could be dispersed to microscopic aggregates by shaking the test tubes. During the next 30 min macroscopic aggregates returned in the glucose solution but not in the iohexol solutions. In 30 min, blood mixed with iohexol solutions never coagulated while blood layered on top of the same iohexol solutions always coagulated. Blood mixed with solutions 5 and 6, both without iohexol, always coagulated. It is concluded that adding 150 mM NaCl to iohexol did not eliminate its ability to antico-agulate whole blood, but inhibited its ability to aggregate red cells. This inhibition was not caused by the osmotic effects of the added NaCl.

Modulation by Heparin of the Interaction of the A1 Domain of von Willebrand Factor With Glycoprotein Ib

Blood ◽  
1999 ◽  
Vol 94 (12) ◽  
pp. 4186-4194 ◽  
Author(s):  
Christelle Perrault ◽  
Nadine Ajzenberg ◽  
Paulette Legendre ◽  
Ghassem Rastegar-Lari ◽  
Dominique Meyer ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Cell Aggregation ◽  
Cell Aggregates ◽  
Critical Determinant ◽  
Amino Terminal ◽  
A Cell ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Amino Terminal Fragment

Abstract The conformation of the A1 domain of von Willebrand factor (vWF) is a critical determinant of its interaction with the glycoprotein (GP) Ib/V/IX complex. To better define the regulatory mechanisms of vWF A1 domain binding to the GPIb/V/IX complex, we studied vWF-dependent aggregation properties of a cell line overexpressing the GPIb, GPIbβ, and GPIX subunits (CHO-GPIbβ/IX cells). We found that CHO-GPIbβ/IX cell aggregation required the presence of both soluble vWF and ristocetin. Ristocetin-induced CHO-GPIbβ/IX cell aggregation was completely inhibited by the recombinant VCL fragment of vWF that contains the A1 domain. Surprisingly, the substitution of heparin for ristocetin resulted in the formation of CHO-GPIbβ/IX cell aggregates. Using monoclonal antibodies blocking vWF interaction with GPIb/V/IX or mocarhagin, a venom metalloproteinase that removes the amino-terminal fragment of GPIb extending from aa 1 to 282, we demonstrated that both ristocetin- and heparin-induced aggregations involved an interaction between the A1 domain of vWF and the GPIb subunit of the GPIb/V/IX complex. The involvement of heparin in cell aggregation was also demonstrated after treatment of heparin with heparinase that abolished CHO-GPIbβ/IX cell aggregation. These results indicated that heparin was able to induce vWF-dependent CHO-GPIbβ/IX cell aggregation. In conclusion, we demonstrated that heparin is capable of positively modulating the vWF interaction with the GPIb/V/IX complex.

scholarly journals Initiation of coconut cell suspension culture from shoot meristem derived embryogenic calli: A preliminary study

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
U. Bhavyashree ◽  
K. Lakshmi Jayaraj ◽  
K. S. Muralikrishna ◽  
K. K. Sajini ◽  
M. K. Rajesh ◽  
...  
Keyword(s):  
Suspension Culture ◽  
Cell Suspension ◽  
Cell Suspension Culture ◽  
Fluorescent Microscopy ◽  
Cell Aggregation ◽  
Shoot Meristem ◽  
Malt Extract ◽  
Embryogenic Calli ◽  
Embryogenic Cell

<p>An attempt was made to establish highly competent embryogenic cell suspension culture in coconut, a species recalcitrant to in vitro culture. Embryogenic calli were initiated from shoot meristem explants of coconut. Y3 medium supplemented with 2.4-D (4.5 μM) and glutamine (34.2 μM) was found to be the best medium to initiate cell suspension. Growth evaluation was done by packed cell volume (PCV) and it was found that maximum growth volume of 9.9% was reached at 200 days of culture initiation. About 52% of viable cells were detected through fluorescent microscopy. Cell aggregation was noticed in Y3 medium supplemented with glutamine (34.2 μM), malt extract (100mg/l), biotin (40.9 μM) and kinetin (9.3 μM), but further progress could not be achieved. It was also observed that embryogenic calli were not of a friable type, but were associated with densely aggregated cells. Because of its hard nature, we were unsuccessful to obtain high quality cell suspension.</p>

Influence of fibrinogen on flow properties of erythrocyte suspensions

1964 ◽  
Vol 207 (5) ◽  
pp. 1035-1040 ◽  
Author(s):  
Roe E. Wells ◽  
Thomas H. Gawronski ◽  
Paul J. Cox ◽  
Richard D. Perera
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Cell Aggregation ◽  
Cell Suspensions ◽  
Fibrinogen Concentration ◽  
Sedimentation Rates ◽  
Cell Aggregates ◽  
Red Cell ◽  
Flow Properties ◽  
Yield Value

The influence of fibrinogen on the flow properties of red cell suspensions (hematocrit 41) was studied by viscometry at low rates of shear (0.1–20 sec–1). These findings were correlated with sedimentation rates and photomicrographical studies of cell aggregation. Fibrinogen concentration was varied from 0.3 to 2.0 g/100 ml. The viscosity of the pure solutions of fibrinogen was independent of shear rate, ranging from 0.87 to 1.7 centipoise (cp) at 37 C. The viscosity of the cell suspensions at 10 sec–1 varied from 4.3 cp in 0.3 g/100 ml fibrinogen to 14 cp in 2 g/100 ml fibrinogen. All suspensions were markedly dependent on shear rate, viscosity increasing in exponential-like fashion as shear rate decreased. Extrapolation of plots of shear stress1/2 versus shear rate1/2 revealed the suspensions to sustain a finite stress without deformation or flow, the "yield value" increasing as fibrinogen concentration increased. Photomicrographs of dilute cell suspensions revealed the formation of cell aggregates and rouleaux, increasing in size and descent velocity as fibrinogen concentration increased.

CD43 Interacts With Moesin and Ezrin and Regulates Its Redistribution to the Uropods of T Lymphocytes at the Cell-Cell Contacts

Blood ◽  
1998 ◽  
Vol 91 (12) ◽  
pp. 4632-4644 ◽  
Author(s):  
Juan M. Serrador ◽  
Marta Nieto ◽  
José L. Alonso-Lebrero ◽  
Miguel A. del Pozo ◽  
Javier Calvo ◽  
...  
Keyword(s):  
T Cell ◽  
T Lymphocytes ◽  
Binding Proteins ◽  
Cell Aggregation ◽  
Actin Binding ◽  
Cell Aggregates ◽  
Actin Binding Proteins ◽  
Cell Contacts ◽  
T Lymphoblasts ◽  
Cell Cell

Abstract Chemokines as well as the signaling through the adhesion molecules intercellular adhesion molecule (ICAM)-3 and CD43 are able to induce in T lymphocytes their switching from a spherical to a polarized motile morphology, with the formation of a uropod at the rear of the cell. We investigated here the role of CD43 in the regulation of T-cell polarity, CD43-cytoskeletal interactions, and lymphocyte aggregation. Pro-activatory anti-CD43 monoclonal antibody (MoAb) induced polarization of T lymphocytes with redistribution of CD43 to the uropod and the CCR2 chemokine receptor to the leading edge of the cell. Immunofluorescence analysis showed that all three ezrin-radixin-moesin (ERM) actin-binding proteins localized in the uropod of both human T lymphoblasts stimulated with anti-CD43 MoAb and tumor-infiltrating T lymphocytes. Radixin localized at the uropod neck, whereas ezrin and moesin colocalized with CD43 in the uropod. Biochemical analyses showed that ezrin and moesin coimmunoprecipitated with CD43 in T lymphoblasts. Furthermore, in these cells, the CD43-associated moesin increased after stimulation through CD43. The interaction of moesin and ezrin with CD43 was specifically mediated by the cytoplasmic domain of CD43, as shown by precipitation of both ERM proteins with a GST-fusion protein containing the CD43 cytoplasmic tail. Videomicroscopy analysis of homotypic cell aggregation induced through CD43 showed that cellular uropods mediate cell-cell contacts and lymphocyte recruitment. Immunofluorescence microscopy performed in parallel showed that uropods enriched in CD43 and moesin localized at the cell-cell contact areas of cell aggregates. The polarization and homotypic cell aggregation induced through CD43 was prevented by butanedione monoxime, indicating the involvement of myosin cytoskeleton in these phenomena. Altogether, these data indicate that CD43 plays an important regulatory role in remodeling T-cell morphology, likely through its interaction with actin-binding proteins ezrin and moesin. In addition, the redistribution of CD43 to the uropod region of migrating lymphocytes and during the formation of cell aggregates together with the enhancing effect of anti-CD43 antibodies on lymphocyte cell recruitment suggest that CD43 plays a key role in the regulation of cell-cell interactions during lymphocyte traffic.

Modulation by Heparin of the Interaction of the A1 Domain of von Willebrand Factor With Glycoprotein Ib

Blood ◽  
1999 ◽  
Vol 94 (12) ◽  
pp. 4186-4194
Author(s):  
Christelle Perrault ◽  
Nadine Ajzenberg ◽  
Paulette Legendre ◽  
Ghassem Rastegar-Lari ◽  
Dominique Meyer ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Cell Aggregation ◽  
Cell Aggregates ◽  
Critical Determinant ◽  
Amino Terminal ◽  
A Cell ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Amino Terminal Fragment

The conformation of the A1 domain of von Willebrand factor (vWF) is a critical determinant of its interaction with the glycoprotein (GP) Ib/V/IX complex. To better define the regulatory mechanisms of vWF A1 domain binding to the GPIb/V/IX complex, we studied vWF-dependent aggregation properties of a cell line overexpressing the GPIb, GPIbβ, and GPIX subunits (CHO-GPIbβ/IX cells). We found that CHO-GPIbβ/IX cell aggregation required the presence of both soluble vWF and ristocetin. Ristocetin-induced CHO-GPIbβ/IX cell aggregation was completely inhibited by the recombinant VCL fragment of vWF that contains the A1 domain. Surprisingly, the substitution of heparin for ristocetin resulted in the formation of CHO-GPIbβ/IX cell aggregates. Using monoclonal antibodies blocking vWF interaction with GPIb/V/IX or mocarhagin, a venom metalloproteinase that removes the amino-terminal fragment of GPIb extending from aa 1 to 282, we demonstrated that both ristocetin- and heparin-induced aggregations involved an interaction between the A1 domain of vWF and the GPIb subunit of the GPIb/V/IX complex. The involvement of heparin in cell aggregation was also demonstrated after treatment of heparin with heparinase that abolished CHO-GPIbβ/IX cell aggregation. These results indicated that heparin was able to induce vWF-dependent CHO-GPIbβ/IX cell aggregation. In conclusion, we demonstrated that heparin is capable of positively modulating the vWF interaction with the GPIb/V/IX complex.

scholarly journals The Grb2/Mek Pathway Represses Nanog in Murine Embryonic Stem Cells

2006 ◽  
Vol 26 (20) ◽  
pp. 7539-7549 ◽  
Author(s):  
Takashi Hamazaki ◽  
Sarah M. Kehoe ◽  
Toru Nakano ◽  
Naohiro Terada
Keyword(s):  
Es Cells ◽  
Tyrosine Phosphatase ◽  
Embryonic Stem ◽  
Homeobox Gene ◽  
Cell Aggregation ◽  
Cell Aggregates ◽  
Es Cell ◽  
Sodium Vanadate ◽  
Primitive Endoderm ◽  
Endoderm Differentiation

ABSTRACT The homeobox gene Nanog is a key intrinsic determinant of self renewal in embryonic stem (ES) cells, and its repression leads ES cells to selectively differentiate into primitive endoderm. Although Nanog repression occurs at the outermost layer of ES cell aggregates independent of the leukemia inhibitory factor (LIF)/STAT3 pathway, it is largely undetermined what external cues and intracellular signals cause the event. Of interest, addition of the tyrosine phosphatase inhibitor, sodium vanadate, selectively repressed Nanog transcription without any detectable changes in upstream transcriptional regulators Oct3/4 and Sox2. Furthermore, sodium vanadate induced primitive endoderm differentiation, even in the inner cells of ES cell aggregates. Expression of Gata6 and Zfp42, two putative downstream Nanog effectors, was also increased and decreased by the addition of sodium vanadate, respectively, but these changes were eliminated by exogenous Nanog expression. The effects of sodium vanadate were abrogated by Grb2 deficiency or by the addition of the Mek inhibitor, PD98059. Indeed, PD98059 prevented Nanog repression induced by ES cell aggregation as well. Furthermore, transfection of a constitutive active Mek mutant into ES cells induced Nanog repression and primitive endoderm differentiation. These data indicate that the Grb2/Mek pathway primarily mediates Nanog gene repression upon ES cell differentiation into primitive endoderm.

scholarly journals Human iPS Cell-Derived Cell Aggregates Exhibited Dermal Papilla Cell Properties in in vitro Three-Dimensional Assemblage Mimicking Hair Follicle Structures

2021 ◽  
Vol 9 ◽  
Author(s):  
Masahiro Fukuyama ◽  
Aki Tsukashima ◽  
Momoko Kimishima ◽  
Yoshimi Yamazaki ◽  
Hideyuki Okano ◽  
...  
Keyword(s):  
Hair Follicle ◽  
Expression Pattern ◽  
Cell Subset ◽  
Dermal Papilla ◽  
Cell Aggregation ◽  
Biological Properties ◽  
Main Body ◽  
Cell Aggregates ◽  
Ips Cell

Current approaches for human hair follicle (HF) regeneration mostly adopt cell-autonomous tissue reassembly in a permissive murine intracorporeal environment. This, together with the limitation in human-derived trichogenic starting materials, potentially hinders the bioengineering of human HF structures, especially for the drug discovery and treatment of hair loss disorders. In this study, we attempted to reproduce the anatomical relationship between an epithelial main body and the dermal papilla (DP) within HF in vitro by three-dimensionally assembling columnarly molded human keratinocytes (KCs) and the aggregates of DP cells and evaluated how HF characteristics were reproduced in the constructs. The replaceability of human-induced pluripotent stem cell (hiPSC)-derived DP substitutes was assessed using the aforementioned reconstruction assay. Human DP cell aggregates were embedded into Matrigel as a cluster. Subsequently, highly condensed human KCs were cylindrically injected onto DP spheroids. After 2-week culture, the structures visually mimicking HFs were obtained. KC-DP constructs partially reproduced HF microanatomy and demonstrated differential keratin (KRT) expression pattern in HFs: KRT14 in the outermost part and KRT13, KRT17, and KRT40, respectively, in the inner portion of the main body. KC-DP constructs tended to upregulate HF-related genes, KRT25, KRT33A, KRT82, WNT5A, and LEF1. Next, DP substitutes were prepared by exposing hiPSC-derived mesenchymal cells to retinoic acid and subsequently to WNT, BMP, and FGF signal activators, followed by cell aggregation. The resultant hiPSC-derived DP substitutes (iDPs) were combined with KCs in the invented assay. KC-iDP constructs morphologically resemble KC-DP constructs and analogously mimicked KRT expression pattern in HF. iDP in the constructs expressed DP-related markers, such as vimentin and versican. Intriguingly, KC-iDP constructs more intensely expressed KRT33A, KRT82, and LEF1, which were stepwisely upregulated by the addition of WNT ligand and the mixture of WNT, SHH, and EDA signaling activators, supporting the idea that iDP exhibited biological properties analogous to DP cell aggregates in the constructs in vitro. These preliminary findings suggested the possibility of regenerating DP equivalents with in vitro hair-inductive capacity using hiPSC-derived cell composites, which potentially reduce the necessity of human tissue-derived trichogenic cell subset and eventually allow xeno-free bioengineering of human HFs.

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