BACKGROUND: Granuloca cells have a key role during estroeidogenesis. OBJECTIVES: The purpose of this study was to determine the effect of number of culture medium granulosa cells on estradiol concentrations and mRNA codding estrogenic and progestagenic enzyme. METHODS: Briefly, follicles between 2 and 5 mm diameter were dissected from the ovaries of adult cows and were collected by rinsing the follicle walls with Dulbecco Modified Eagle medium/F12 (DMEM/F12). The number of cells was counted with a haemocytometer and the viable cells were assessed by the dye exclusion method using 0.4% Trypan Blue. Treatments were 1) 500,000 cell/500 ml, 2) 250,000 cell/500 ml, 3) 500,000 cell/200 ml 4) 250,000 cell/ 200 ml.  All data were analyzed by JMP (SAS). RESULTS: Low plating density increased E2 secretion and mRNA encoding LHR, FSHR and estrogenic enzymes (17βHSD, CYP19), whereas decreased mRNA encoding GADD45β. There were no differences among treatments for RNA and protein concentration. Low plating density also decreased protein amount but there was no difference among treatments for RNA amount. In conclusion, decreased cell density cause increase in mRNA encoding codding estrogenic enzyme gene expression and decrease in mRNA encoding progestagenic enzyme gene expression. CONCLUSIONS: Protein concentrations did not changed with decreased cell density therefore we can save cells against harmful effect of increasing cell density.

Bovine pulmonary artery cells in cell culture were exposed to lipopolysaccharide (LPS) purified from Pasteurella haemolytica serotype A1. This resulted in severe membrane damage, which caused a time- and dose-dependent release of lactate dehydrogenase that was first detected 4 hours after exposure and reached a maximal mean release of 67% after 24 hours of exposure to 1 microgram of LPS/ml. Mean release of 51chromium followed by a similar pattern and reached a maximum of 61% following 24 hours of exposure to 10 micrograms of LPS/ml. Morphologically, endothelial cells responded to LPS by marked cell membrane retraction, the formation of numerous cytoplasmic blebs, and ruffling of the cell membrane. Subsequently, the cells became round and detached. Cell detachment reached a mean of 95% following 8 hours of exposure to 1 microgram of LPS/ml. These studies demonstrated that P haemolytica LPS is capable of causing direct damage to bovine pulmonary arterial endothelial cells, which may be important in the pathogenesis of bovine pneumonic pasteurellosis.

Growth of Pasteurella haemolytica A1 in RPMI 1640 medium containing 0.5% bovine serum albumin (BSA) for 2.5 hours enhanced culture supernatant leukotoxic activity [30,700 +/- 12,900 toxic units/ml, compared with leukotoxic activity of culture supernatants produced in RPMI 1640 medium alone (120 +/- 40 toxic units/ml)]. Gel filtration chromatography of the leukotoxic activity from RPMI 1640 medium supernatants in buffer containing 50 mM NaCl indicated a single leukotoxic activity peak (peak I) eluting near the gel resin molecular mass exclusion limit (estimated molecular mass of approx 8,000 kd). In contrast, culture supernatants produced in RPMI 1640 plus bovine serum albumin medium (RPMI + BSA) had peak I and 2 additional leukotoxic activity peaks (peaks II and III) with estimated molecular mass of approximately 80 and < 30 kd, respectively. All leukotoxic activity peaks were composed of approximately 100-kd molecular mass leukotoxin protomer, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with a monoclonal antibody against leukotoxin. Subjecting culture supernatant leukotoxic activity produced in RPMI + BSA to gel filtration chromatography in buffer containing 500 mM NaCl or 6M urea resulted in detection of only a single leukotoxic activity peak with estimated approximate molecular mass of 250 and 800 kd, respectively. These findings suggest that P haemolytica exists as a high molecular mass aggregate with low leukotoxic activity which, in the presence of BSA, partially disaggregates to multiple toxin forms with enhanced leukotoxic activity. Some of these leukotoxin forms interact with dextran-based gel resins at low ionic strength.

The antibiotic polymyxin B sulfate is a cationic polypeptide with a unique cyclical configuration and distinct cationic characteristics. In this investigation, polymyxin B was evaluated to determine its ability to prevent synthesis of lactic acid and tumor necrosis factor-alpha (TNF-alpha) by lipopolysaccharide-stimulated strain RAW 2647 macrophage-like cell populations. In this context, gradient concentrations of polymyxin B were formulated in the presence of fixed concentrations of lipopolysaccharide fractions from Escherichia coli (B4:0111), E. coli (J5), Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella minnesota, and S. typhimurium (Re). Quantitation of TNF-alpha was established by the application of a tissue culture-based biological assay system, using the WEHI 164 clone 13 indicator cell line. Investigations also included evaluation of the ability of gradient concentrations of lipopolysaccharide fractions from E. coli (B4:0111), E. coli (J5), K. pneumoniae, P. aeruginosa, S. minnesota, and S. typhimurium (Re) to form a complex with polymyxin B. This was established through application of high-performance thin-layer chromatography techniques. On the basis of the known molecular characteristics of lipopolysaccharide, its lipid A-core subfractions, and polymyxin B, these results imply that cytoprotective properties of polymyxin B are attributable to direct interaction and subsequent complex formation. More specifically, the mechanism by which polymyxin B exerts affinity for lipopolysaccharide fractions is proposed to occur through attractive ionic interactions established between the cationic diaminobutyric acid residues of polymyxin B and the mono- or diphosphate group(s) of the lipid A-core moiety. It is highly probable that this molecular phenomenon is accompanied by hydrophobic interactions established between the terminal methyloctanoyl or methylheptanoyl groups of polymyxin B and the saturated carbon chains of the lipid A-core subfraction of lipopolysaccharide fractions.

The amphotropic murine leukemia virus (MLV) has been shown to infect mammalian species other than mice. If this virus infects and expresses genes in cells of livestock species (cattle, sheep, and pigs) it has potential for use as a vector to produce transgenic livestock. Because the gene-injection technique for producing transgenic animals is inherently inefficient, our laboratory was interested in identifying or constructing retroviral vectors capable of infecting livestock embryos. The infectivity of an amphotropic MLV-based vector for ovine, bovine, and porcine cells was tested. Experiments were also conducted to test the ability of the amphotropic MLV promoter, compared with known strong promoters, to express genes in cells from these species. Results indicated that amphotropic MLV infects and expresses genes efficiently in porcine cells and is, therefore, a potential vector for producing transgenic pigs. Infection was not detected in cells from adult bovine and ovine species; however, low levels of infection, with subsequent gene expression, were detected in cells derived from bovine embryos.

A penta-dog inactivated cell culture vaccine was prepared to protect dogs againstcanine distemper virus, canine parvovirus, canine adenovirus1, 2 and rabies virus.The potency of this vaccine was compared with that of single inactivated vaccinesprepared against each disease, in different groups of susceptible dogs. It was foundthat the protective dose of penta-dog vaccine (2ml) including the protective amounts of the five viral proteins resulted in full protection of vaccinated dogs against the challenge with virulent strain of the used viruses showing no antagonizing effect between each other with and no adverse postvaccinal reaction. So, the prepared inactivated cell culture penta-dog vaccine is a safe and potent vaccine for dogs which resulted in saving time, cost, and effort stress factors on animals and providing good immune statues.

The present study was designed in a trial to use serum replacement instead of thenewborn calf serum in propagation of BHK-21 cell cultures with subsequent reducingthe cost of foot and mouth disease (FMD) vaccine production. Two batches of BHK-21 cell culture were prepared where the medium of the first batch was supplemented with newborn calf serum while the medium of the second batch was supplemented with serum replacement. FMD virus was propagated 7 passages using BHK-21 cell culture. Both virus titration and complement fixation titer (CF) revealed that propagation of FMD virus in cell cultures supplemented with newborn calf serum yields a titre higher than that in case of cells supplemented with serum replacement. Also two batches of FMD inactivated vaccine were prepared from the virus propagated in the two-mentioned cell culture batches. Two groups of susceptible calves were vaccinated with these vaccines. Both of virus neutralization test (VNT) and enzyme linked immunosorbent assay (ELISA) revealed that higher antibody levels were induced in calves vaccinated with the vaccine prepared from cells supplemented with calf serum than those vaccinated with vaccine prepared from cells grown with serum replacement. BHK-21 cell culture supplement with newborn calf serum is most susceptible for FMD virus propagation yielding higher titer of the virus. Moreover, the growth pattern of the used cell culture was much better when the newborn calf serum was used.

Avian coronavirus (AvCoV) infects a range of tissues in chickens and several other avian species. Although the virus can be isolated in chicken embryos, only a few strains of the 6 genotypes/33 lineages can grow in cell lines, with the Beaudette strain (GI-1 lineage) being the most used for in vitro studies. Considering the differences between cell lines and chicken embryos as habitats for AvCoV, this study aimed to assess the diversity of the genes coding for the nonstructural protein 3 (nsp3) and spike envelope protein (S) after serial passages in BHK-21 and Vero cells. After 14 passages of an embryo-adapted Beaudette strain, the virus loads fluctuated in both cell lines, with the highest loads being 8.72 log genome copies/µL for Vero and 6.36 log genome copies/µL for BHK-21 cells. No polymorphisms were found for nsp3; regarding S, not only aa substitutions (Vero: 8th passage A150S, and 14th S150A; BHK-21: 4th S53F, 8th F53Y, and 8th S95R), but also minor variants could be detected on chromatograms with fluctuating intensities. As the regions of these aa substitutions are within the receptor-binding domain of S, it can be speculated that differences in cell receptors between Vero and BHK-21 cells and the speed of cell death led to the selection of different dominant strains, while the stability of nsp3 supports its function as a protease involved in AvCoV replication. In conclusion, AvCoV quasispecies evolution is influenced by the biological model under consideration, and a gradual transition is seen for minor and major variants.