Low protein

About: Low protein is a research topic. Over the lifetime, 8139 publications have been published within this topic receiving 213225 citations.

Performance of growing pullets and laying hens fed low protein amino acid supplemented diets

Abstract: An experiment was conducted to determine the effect of feeding low-protein, amino acid-supplemented diets during growing and laying periods on performance of a commercial strain of White Leghorn chickens. The birds of the positive control were fed diets in a sequence of 20, 16, and 14% protein during 0 to 6, 6 to 12, and 12 to 18 wk (growing period) and of 18, 16.5, and 15% protein during 18 to 34, 34 to 50, and 50 to 66 wk of age (laying period). The birds of the negative control were fed protein levels of 16, 13.5, and 11.5% in the growing period and 14, 13, and 12% in the laying period. Other groups were fed the negative control series supplemented with methionine, methionine plus lysine, or methionine plus lysine plus other deficient essential amino acids. An additional group was fed the negative control supplemented with methionine plus lysine during the growing period and a protein sequence of 15, 14, and 13% supplemented with methionine and lysine during the laying period. At 18 wk of age, birds fed the negative control supplemented with methionine plus lysine or methionine plus lysine plus other deficient essential amino acids had comparable body weight to those fed the positive control despite significantly lower protein and lysine intake. Overall egg production and egg weight of birds fed the sequence of 14, 13, and 12% protein supplemented with combination of methionine, lysine, and extra levels of tryptophan and isoleucine or of the birds fed the sequence of 15, 14, and 13% protein supplemented with methionine and lysine were not different from those fed the positive control. However, egg mass and body weight were inferior to those of birds fed the positive control.

Pulsed electron-electron double-resonance determination of spin-label distances and orientations on the tetrameric potassium ion channel KcsA.

Abstract: Pulsed electron-electron double-resonance (PELDOR) measurements are presented from the potassium ion channel KcsA both solubilized in detergent and reconstituted in lipids. Site-directed spin-labeling using (1-oxyl-2,2,5,5-tetramethyl-3-pyrrolin-3-yl)methyl methanethiosulfonate was performed with a R64C mutant of the protein. The orientations of the spin-labels in the tetramer were determined by PELDOR experiments performed at two magnetic field strengths (0.3 T/X-band and 1.2 T/Q-band) and variable probe frequency. Quantitative simulation of the PELDOR data supports a strongly restricted nitroxide, oriented at an angle of 65 degrees relative to the central channel axis. In general, poorer quality PELDOR data were obtained from membrane-reconstituted preparations compared to soluble proteins or detergent-solubilized samples. One reason for this is the reduced transverse spin relaxation time T(2) of nitroxides due to crowding of tetramers within the membrane that occurs even at low protein to lipid ratios. This reduced T(2) can be overcome by reconstituting mixtures of unlabeled and labeled proteins, yielding high-quality PELDOR data. Identical PELDOR oscillation frequencies and their dependencies on the probe frequency were observed in the detergent and membrane-reconstituted preparations, indicating that the position and orientation of the spin-labels are the same in both environments.

Expression of cyclin D1, D3, E, and p27 in human renal cell carcinoma analysed by tissue microarray.

Abstract: Aberrations in the G1/S transition of the cell cycle have been observed in many malignancies and seem to be critical in the transformation process. Few studies have delineated the presence of G1/S regulatory defects and their clinical relevance in renal cell carcinoma (RCC). Therefore, we have examined the protein contents of cyclin D1, D3, E, and p27 in 218 RCCs, using tissue microarray and immunohistochemistry. The results from a subset of tumours were confirmed by Western blotting and immunohistochemical staining of regular tissue sections. Interestingly, low protein contents of cyclin D1 and p27 were associated with high nuclear grade, large tumour size, and poor prognosis for patients with conventional tumours. We further observed substantial differences in the pattern of G1/S regulatory defects between the different RCC subtypes. The majority of both conventional and papillary cases expressed p27; however, chromophobe tumours generally lacked p27 staining. In addition, conventional RCCs often expressed high cyclin D1 protein levels, while papillary RCCs exhibited high cyclin E. In summary, we have shown that G1/S regulatory defects are present in RCC and are associated with clinico-pathological parameters. The pattern of cell cycle regulatory defects also differed between RCC subtypes.