Testes of DAZL null neonatal sheep lack prospermatogonia but maintain normal somatic cell morphology and marker expression

2020 ◽  
Author(s):  
Zachariah L. McLean ◽  
Sarah J. Appleby ◽  
Jingwei Wei ◽  
Russell G. Snell ◽  
Björn Oback
Keyword(s):  
Somatic Cell ◽  
Cell Morphology ◽  
Marker Expression ◽  
Normal Somatic Cell

Frequency of subclinical mastitis and observations on somatic cell counts in ewes' milk in northern Greece

1995 ◽  
Vol 61 (1) ◽  
pp. 69-76 ◽  
Author(s):  
A. Stefanakis ◽  
C. Boscos ◽  
C. Alexopoulos ◽  
F. Samartzi
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Somatic Cell Count ◽  
Subclinical Mastitis ◽  
Coulter Counter ◽  
Coagulase Negative Staphylococci ◽  
Northern Greece ◽  
Milk Samples ◽  
Ewe's Milk ◽  
Normal Somatic Cell

AbstractSomatic cell counting by the Coulter Counter method, California mastitis test and bacteriological examination were performed on milk samples taken at fortnightly intervals throughout lactation from healthy primiparous and iniiltiparous ewes of the Chios and Karagouniki breeds and from healthy ewes in five grazing flocks in northern Greece.The proportion of the bacteriologically positive milk samples was 0·22. The prevalence of subclinical mastitis ranged, between the flocks, from 29 to 43% of the ewes. Subclinical mastitis occurred more frequently in Karagouniki than in Chios eives and in multiparous than in primiparous ewes of both breeds. Coagulase-negative staphylococci and S. aureus were isolated in 44 and 33% of the bacteriologically postive samples, respectively. No parity, breed or flock differences in normal somatic cell count were noticed, but stage of lactation influenced normal somatic cell count both in primiparous and multiparous ewes. The results of this investigation also suggest that (a) ovine milk samples with somatic cell count more than 1000 × 103 cells per ml, should be tested bacteriologically, (b) somatic cell count values between 1000 and 2000 × 103 cells per ml should cause suspicion about the presence of coagulase-negative staphylococci in the milk, and (c) the presence of S. aureus in ewe's milk results in a significant increase in somatic cell count, but the wide range of the values does not permit us to suggest any threshold value. The significant correlation between the results of the Coulter Counter somatic cell count method and the Califortiia mastitis test, indicates that the latter can be used for the determination of somatic cell count in ewe's milk.

Cell morphology, volume, and surface area determinations from multilevel contouring within HVEM micrographs of serial sections and whole-cell mounts

1987 ◽  
Vol 45 ◽  
pp. 588-589
Author(s):  
M. Marko ◽  
A. Leith ◽  
D. Parsons
Keyword(s):  
Surface Area ◽  
Electron Micrographs ◽  
Cell Morphology ◽  
Individual Variation ◽  
Serial Section ◽  
Stereo Pair ◽  
Complex Structures ◽  
Serial Sections ◽  
Surface Areas ◽  
Computer Based

The use of serial sections and computer-based 3-D reconstruction techniques affords an opportunity not only to visualize the shape and distribution of the structures being studied, but also to determine their volumes and surface areas. Up until now, this has been done using serial ultrathin sections.The serial-section approach differs from the stereo logical methods of Weibel in that it is based on the Information from a set of single, complete cells (or organelles) rather than on a random 2-dimensional sampling of a population of cells. Because of this, it can more easily provide absolute values of volume and surface area, especially for highly-complex structures. It also allows study of individual variation among the cells, and study of structures which occur only infrequently.We have developed a system for 3-D reconstruction of objects from stereo-pair electron micrographs of thick specimens.

Sign in / Sign up

Export Citation Format

Share Document