Determination of immunoglobulin concentrations and genetic parameters for colostrum and calf serum in Charolais animals.

Colostrum samples from 366 Charolais primiparous cows, as well as serum from their calves at 24 to 48 h of age, were collected to gain an overview of the situation regarding passive immune transfer in beef cattle, from both the phenotypic and genetic points of view. All samples were analyzed to quantify their G1 immunoglobulins by radial immunodiffusion (RID) and their IgG, IgA, and IgM using ELISA. The average concentrations obtained in colostrum were 84 mg/mL for RID-IgG1, and 158 mg/mL, 4.5 mg/mL and 10.8 mg/mL for ELISA-IgG, -IgA, and -IgM, respectively. The corresponding values in calf serum were 19.9, 30.6, 1.0, and 1.9 mg/mL. Apart from the general environmental effect (farm-year combination and laboratory conditions), the characteristics of the dams tested did not reveal any influence on colostrum immunoglobulin concentrations. Calving difficulty, as well as the birth weight and sex of calves, were found to be associated with serum concentrations in some cases. Heritability estimates were low to moderate, with the highest being for RID-IgG1 in colostrum (h2 = 0.28, standard error = 0.14) and serum (h2 = 0.36, standard error = 0.18). Phenotypic correlations among the different immunoglobulins were generally positive or null, and none of the genetic correlations were significant due to large standard errors. The phenotypic correlation between dam colostrum and calf serum values was 0.2 for RID-IgG1 and null for the 3 ELISA measurements. The correlation between RID-IgG1 and ELISA-IgG was, unexpectedly, null for colostrum and 0.4 for serum. Increased RID-IgG1 levels in calf serum were associated with improved survival, as well as better early growth and fewer health problems. These results thus showed that despite generally higher concentrations in beef than in dairy cattle, passive transfer was unsuccessful in a considerable number of calves. This should be brought to the attention of breeders to avoid negative effects on survival and subsequent performance. The heritability estimates were encouraging; however, obtaining phenotypes on a large scale constitutes a real limitation regarding these traits.

Selectively 13C-enriched DNA: dynamics of the C1'-H1' vector in d(CGCAAATTTGCG)2.

In order to examine the internal dynamic processes of the dodecamer d(CGCAAATTTGCG)2, the 13C-enriched oligonucleotide has been synthesized. The three central thymines were selectively 13C-labeled at the C1' position and their spin-lattice relaxation parameters R(CZ), R(CX,Y), R(HZ-->CZ), R(2HZCZ), R(2HZCX,Y) and R(HZC) were measured. Density functions were computed for two models of internal motions. Comparisons of the experimental data were made with spin-lattice relaxation rates rather than with the density functions, whose values were altered by accumulation of the uncertainties of each relaxation rate measurement. The spin-lattice relaxation rates were computed with respect to the motions of the sugar around the C1'-N1 bond. A two-state jump model between the anti- and syn-conformations with P(anti)/P(syn) = 91/9 or a restricted rotation model with delta chi = 28 degrees and an internal diffusion coefficient of 30 x 10(7) s-1 gave a good fit with the experimental data. Twist, tilt or roll base motions have little effect on 13C1' NMR relaxation. Simulation of spin-relaxation rates with the data obtained at several temperatures between 7 and 32 degrees C, where the dodecamer is double stranded, shows that the internal motion amplitude is independent of the temperature within this range, as expected for internal motion. Using the strong correlation which exists in a B-DNA structure between the chi and delta angle, we suggest that the change in the glycosidic angle value should be indicative of a sugar puckering between the C1'-exo and C2'-endo conformations.

Selectively 13C-enriched DNA: 13C and 1H assignments of a triple helix by two-dimensional relayed HMQC experiments.

We present NMR studies of an intramolecular triple helix, the three strands of which have been linked by a hexaethylene glycol chain. To overcome the generally encountered difficulties of assignment in the homo-pyrimidine strands, the carbon Cl' of the pyrimidines were selectively 13C-enriched. Assignments of the aromatic and sugar protons were obtained from NOESY-HMQC and TOCSY-HMQC spectra. We show that the recognition of a DNA duplex by a third strand via triplex formation is easily carried out in solution by observing the changes of the 1Hl'-13Cl' connectivities as a function of pH. Furthermore, the conformation of the sugars has been found to be C2'-endo, on the basis of the coupling constant values directly measured in an HSQC spectrum.