Ah-receptor-independent stimulation of hepatoma 27 culture cell proliferation by polycyclic aromatic hydrocarbons.

The proliferative effect of some compounds that are aryl hydrocarbon (Ah) receptor ligands was studied on hepatoma 27 cells with absent expression of Ah receptor. Compounds of the polycyclic aromatic hydrocarbon (PAH) class benzo/a/pyrene, 3-methylcholanthrene, 7,12-dimethylbenz/a/anthracene, and benzo/e/pyrene as well as ß-naphthoflavone (ß-NF) and chlorinated hydrocarbon Aroclor 1254 were studied. It was found that carcinogenic PAH and ß-NF stimulate cell proliferation both under conditions of standard serum content and in a medium with low serum content. More efficient stimulation of proliferation was observed in the case of low serum content. Aroclor 1254 and benzo/e/pyrene did not stimulate cell proliferation. Stimulation of proliferation was accompanied by activation of the ERK1/2-dependent MAP-kinase cascade. Benzo/a/pyrene caused a decrease in the number of cells in G1 phase of the cell cycle and increase in number of cells in G2/M phases under conditions of cell growth in media with low serum content. Carcinogenic PAH and ß-NF activated transcription factor AP-1, and in this case activation was more pronounced in cells grown in medium with low serum content. A possible mechanism of activation of proliferation by an Ah receptor-independent pathway is discussed.

[Activation of transcription factor NF-kappaB by carcinogenic polycyclic aromatic hydricarbons].

Effect of carcinogenic polycyclic aromatic hydrocarbons (PAH) benzo(a)pyrene (BP) and 3-methylcholanthrene (MC) on transcription factor NF-kappaB activation was studied. The determination of NF-kappaB activity was performed by two different methods: determination of mRNA expression of NF-kappaB-dependent I-kappaB gene, and determination of transcription activity of co-transfected with the plasmid containing the luciferase reporter gene under the NF-kappaB-sensitive promoter. As a subject of inquiry the hepatoma cell cultures HepG2 expressed Ah receptor and G27 not expressed Ah receptor were used. BP and MC weekly enhanced NF-kappaB activity in proliferating HepG2 cells. The enhance of NF-kappaB activity was significantly higher in resting cells. NF-kappaB activation by BP and MC in hepatoma G27 cells was significantly higher in hepatima G27 cells than in HepG2 cells both in proliferating and resting cells. The role of Ah receptor in PAH action on NF-kappaB activation is discussed.

Development of a duplex real-time TaqMan PCR assay with an internal control for the detection of Mycoplasma gallisepticum and Mycoplasma synoviae in clinical samples from commercial and backyard poultry.

In this study, we report the development and validation of a duplex real-time polymerase chain reaction (PCR) assay with an internal control using TaqMan-labelled probes for the detection of Mycoplasma gallisepticum and Mycoplasma synoviae (duplex MGMS PCR). The MGMS PCR was highly specific with a sensitivity of 7 and 1 colony-forming units/ml for M. gallisepticum and M. synoviae, respectively, using dilution of pure culture that corresponds to 34 and 29 DNA copies per reaction. Validation of the assay was completed with 260 and 27 pooled samples (tracheal swabs) from commercial chickens and turkeys, respectively, with potential M. gallisepticum and M. synoviae involvement and 42 samples (palatine cleft swabs) from backyard geese and ducks. Using isolation as the gold standard, the MGMS PCR was more sensitive than isolation and the analytical sensitivity was 0.944 and 0.958 for M. gallisepticum and M. synoviae, respectively. In comparison with a gapA-based assay (gapA PCR) and a 16S rRNA-based assay (16S PCR) for M. gallisepticum and M. synoviae, respectively, the results agreed for 94.5% and 96.6%, respectively. The use of the internal control allowed monitoring of proper extraction and inhibition of amplification that was detected in 12 samples. The duplex MGMS PCR was shown to be superior to the presently reported real-time PCR assays in terms of combination of sensitivity, specificity and capacity of detection of more than one target in a single tube. In conclusion, the duplex MGMS PCR was highly specific, sensitive, and reproducible and could be used on clinical samples from commercial chickens, turkeys and backyard poultry including ducks and geese.

[Digestion of raw and culinarily treated meat from cattle of Ural breeds]. / Perevarivanie belkov syrogo i kulinarnoobrabotannogo miasa korov ural'skikh porod.

One of the basic indicators specifying the quality of food products in general and culinary ones in particular is the extent of their assimilation in the gastrointestinal tract. Three culinary portions (sirloin, the outer part of the hind leg and the streak) of the beef of the Urals varieties horned cattle (black-mottled and Tagil) were investigated by the method of pepsin and trypsin digestion. The meat was analysed in the raw, cooked and fried state. The progress of the proteins proteolysis was controlled with reference to the tyrosine accretion. The raw meat was found to undergo digestion at a rather slow rate. The sirloin gets hydrolysed better than the other culinary portions. The meat of the Tagil variety is digested significantly in a more complete fashion than do the corresponding culinary parts of the black-mottle cattle. After heat treatment of the meat in all cases is demonstrable a material acceleration of the proteins proteolysis process, frying yielding a higher degree of splitting the meat proteins by comparison with cooking. Of the culinary portions under study it is the sirloin that shows the highest rate of digestion in its culinarily treated form, the outer part of the hind leg and the streak coming next. The fried and cooked meat of the most culinary portions of the Tagil variety undergo a more complete hydrolysis by comparison with black-mottled cattle meat. All this justifies recommending the meat of the Tagil variety horned cattle for obtaining the highest quality culinary products.