scholarly journals Processing of semen by density gradient centrifugation selects spermatozoa with longer telomeres for assisted reproduction techniques

2015 ◽  
Vol 31 (1) ◽  
pp. 44-50 ◽  
Author(s):  
Qingling Yang ◽  
Nan Zhang ◽  
Feifei Zhao ◽  
Wanli Zhao ◽  
Shanjun Dai ◽  
...  
Keyword(s):  
Density Gradient ◽  
Assisted Reproduction ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Assisted Reproduction Techniques

scholarly journals Effect of Osmolarity and Density of Colloid Formulations on the Outcome of SLC-Selection of Stallion Spermatozoa

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
J. M. Morrell ◽  
A. Johannisson ◽  
H. Rodriguez-Martinez
Keyword(s):  
Density Gradient ◽  
Assisted Reproduction ◽  
Density Gradient Centrifugation ◽  
Sperm Quality ◽  
Gradient Centrifugation ◽  
Single Layer ◽  
Normal Density ◽  
High Osmolarity ◽  
Sperm Survival ◽  
Selection Of

The osmolarity and density of colloids used to prepare spermatozoa for assisted reproduction may affect sperm quality in the resultant preparation. In this study, two osmolarities of Androcoll-E for single-layer or density gradient centrifugation of stallion spermatozoa were compared: “normal” (320 mOsm) or “high” (345 mOsm). Mean yields for the two centrifugation techniques did not differ between treatments or osmolarities (single layer centrifugation: 30.19±16.9×106 and 25.8±18.5×106 spermatozoa; density gradient centrifugation: 31.84±19.7×106 and 26.46±20.0×106 spermatozoa respectively for the two osmolarities). However, use of the high osmolarity colloid for single layer centrifugation increased the proportion of morphologically normal spermatozoa (P<.05). Therefore, increasing the osmolarity of the colloid formulation may be beneficial for processing ejaculates containing a high proportion of abnormal spermatozoa by SLC. Reducing the density of the colloid used for the SLC substantially increased the yield of motile spermatozoa compared to the normal density colloid (mean ± SD: 72.6±28.9×106 versus 28.9±24.7×106), while also prolonging sperm survival by 24 hours compared to the uncentrifuged ejaculate. This increased yield may render Single Layer Centrifugation practical for use in the field.

Uranyl Acetate and Rotary Shadowing to Increase the Contrast of Small Aggregated Virus Particles

1969 ◽  
Vol 27 ◽  
pp. 424-425
Author(s):  
Lee F. Ellis ◽  
Richard M. Van Frank ◽  
Walter J. Kleinschmidt
Keyword(s):  
Electron Microscopy ◽  
Tissue Culture ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Uranyl Acetate ◽  
Interferon Inducer ◽  
Virus Particles ◽  
Staining Methods ◽  
Rotary Shadowing

The extract from Penicillum stoliniferum, known as statolon, has been purified by density gradient centrifugation. These centrifuge fractions contained virus particles that are an interferon inducer in mice or in tissue culture. Highly purified preparations of these particles are difficult to enumerate by electron microscopy because of aggregation. Therefore a study of staining methods was undertaken.

The Combining Ability of Glycoproteins IIb, IIIa and Ca2+ in EDTA-Treated Nonaggregable Platelets

1983 ◽  
Vol 50 (04) ◽  
pp. 848-851 ◽  
Author(s):  
Marjorie B Zucker ◽  
David Varon ◽  
Nicholas C Masiello ◽  
Simon Karpatkin
Keyword(s):  
Density Gradient ◽  
Combining Ability ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Electrophoretic Pattern ◽  
Sucrose Density Gradient ◽  
Irreversible Loss ◽  
Sucrose Density Gradient Centrifugation ◽  
Crossed Immunoelectrophoresis ◽  
Triton X

SummaryPlatelets deprived of calcium and incubated at 37° C for 10 min lose their ability to bind fibrinogen or aggregate with ADP when adequate concentrations of calcium are restored. Since the calcium complex of glycoproteins (GP) IIb and IIIa is the presumed receptor for fibrinogen, it seemed appropriate to examine the behavior of these glycoproteins in incubated non-aggregable platelets. No differences were noted in the electrophoretic pattern of nonaggregable EDTA-treated and aggregable control CaEDTA-treated platelets when SDS gels of Triton X- 114 fractions were stained with silver. GP IIb and IIIa were extracted from either nonaggregable EDTA-treated platelets or aggregable control platelets with calcium-Tris-Triton buffer and subjected to sucrose density gradient centrifugation or crossed immunoelectrophoresis. With both types of platelets, these glycoproteins formed a complex in the presence of calcium. If the glycoproteins were extracted with EDTA-Tris-Triton buffer, or if Triton-solubilized platelet membranes were incubated with EGTA at 37° C for 30 min, GP IIb and IIIa were unable to form a complex in the presence of calcium. We conclude that inability of extracted GP IIb and IIIa to combine in the presence of calcium is not responsible for the irreversible loss of aggregability that occurs when whole platelets are incubated with EDTA at 37° C.

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