Induction of blastogenesis in bovine peripheral blood lymphocytes by oxidation with sodium periodate

Suitable treatment and culture conditions are defined for the induction of blast transformation in bovine peripheral blood lymphocytes by oxidation with sodium metaperiodate (NaIO4). Stimulation with NaIO4 required slight modification of techniques used routinely for activation of lymphocytes in vitro with lectins and antigens. Gradient-separated mononuclear leukocytes responded with maximal [3H]TdR incorporation after oxidation with 0.50 to 1.0 mM NaIO4 for 30 minutes at 25 C. Oxidized cells cultured at 1 to 2 X 10(6)/ml responded better than cells cultured at any other concentration, when compared with untreated cells. Blastogenesis in response to oxidation reached its maximum rate within 48 hours of treatment, after which it declined rapidly. Partial removal of glass wool-adherent cells reduced periodate-triggered blastogenesis by 95%, but did not significantly affect activation with phytohemagglutinin, concanavalin A, pokeweed mitogen, or purified protein derivative. Reintroduction of macrophages restored responses to their precolumn level. Oxidation with NaIO4 provided a simple, rapid means of inducing blastogenesis in bovine lymphocytes. Manipulation of the well-defined triggering conditions may help to explain the mechanisms involved in lymphocyte activation.     

Long-term storage of blood prior to whole-blood lymphocyte culturing

Studies were conducted to investigate the effect on blastogenesis of long-term storage of blood prior to whole-blood lymphocyte culturing. Peripheral blood from normal cattle was utilized. Blood from each animal was divided into 2 parts, A and B, following collection. Part A was left intact while RPMI-1640 culture medium was added to part B immediately following collection. Both parts were then kept at room temperature for a total of 7 days and a portion of each blood was tested every day. The cultures were incubated and assayed for [³H] thymidine incorporation into their DNA. It was observed that intact blood (A) was good for 4 days but deteriorated thereafter. Addition of RPMI-1640 to B prolonged the keeping quality of blood for 7 days prior to culturing. The possible application of these findings are discussed.     

The effect of breed of sire and age at feeding on muscle tenderness in the beef chuck

Steers (n = 59) produced from the mating of Braford, Simbrah, Senepol, and Simmental bulls to Brahman- and Romana Red-sired cows and Brahman bulls to Angus cows were used in this study. Effects of sire breed and age at feeding on muscle tenderness in the major muscles of the chuck when steers were fed to 1.0 cm 12th rib fat were determined. There were no muscle tenderness effects due to sire breed group, with the exception of the serratus ventralis muscle, which was more tender in Brahman- and Braford-sired steers than in Simmental-sired steers. Additionally, the supraspinatus muscle from the yearlings was lower in shear value than that from the calves. The Brahman-sired steers had serratus ventralis muscles with higher percentages (P less than .05) of intramuscular fat than those of Braford-, Simbrah-, and Simmental-sired steers. Fat deposited within the muscle or between muscles in the chuck was not related to muscle tenderness as measured by Warner-Bratzler shear values. Also, percentages of intramuscular fat of the triceps brachii, serratus ventralis, or supraspinatus muscles were not influenced (P greater than .05) by age at feeding.     

Involvement of calcium in mitogenic and immunoglobulin responses in bovine lymphocytes

Removal of calcium from cultures of bovine splenic lymphoid cells with ethyleneglycol-bis-(2-amino ethylether)-N,N'-tetraacetic acid (EGTA) caused significant suppression of pokeweed mitogen-induced immunoglobulin (Ig) biosynthesis. It was found that removal of calcium for 48 hours of a 5-day culture significantly altered Ig biosynthesis. Re-addition of calcium after 48 hours did not restore Ig synthesis. The EGTA caused significant (P < 0.05) suppression of DNA synthesis when calcium was removed from concanavalin A- and purified protein derivative-stimulated peripheral blood lymphocyte cultures. Further, removal of calcium for 48 hours of 4-day cultures significantly altered the DNA synthesis in mitogen- and antigen-stimulated cultures.     

Analyzing spatial and temporal phenomena using geographical information systems

In ecological studies the recent emphasis on larger study areas over longer time spans has coincided with the development of geographical information systems (GIS). GISs are a set of computer hardware and software for analyzing and displaying spatially referenced features (i.e., points, lines, polygons) with non-geographic attributes (i.e., species, age). In the fields of natural resources management and ecology the GIS has been used most frequently for 1) derivation of area or length measures, 2) spatial intersection functions such as file merging, analysis of spatial coincidence and detection of temporal change, 3) proximity analyses, and 4) derivation of data for input in simulation or growth models or calculation of specific metrics. Several current applications of GISs in ecology and natural resources are reviewed.     

Estimates of genetic parameters for direct and maternal effects on embryonic survival in swine.

Survival of 16,838 potential embryos was determined by counting corpora lutea and fetuses at 50 d of gestation for 1,081 litters by 225 sires. These data, coded as 1 or 0 depending on whether an ovulation was represented by a fetus, were used to estimate direct and maternal additive genetic variances and their covariance for embryonic survival. Data were from first-parity gilts of a Large White-Landrace composite population subdivided into two lines, one selected for an index of ovulation rate and embryonic survival for seven generations and a contemporary control line. Variance components were obtained by ANOVA and expectations of covariances among relatives and by derivative-free restricted maximum likelihood (DFREML) in an animal model. As a trait of the embryo, heritability of direct effects obtained with ANOVA was 3.8%, heritability of maternal effects was 1.5%, and the genetic correlation between them was -.51. After adjustment of embryonic survival for ovulation rate, lower estimates of each parameter were obtained with ANOVA. Heritability of embryonic survival as a trait of the dam was 9 to 10%. Estimates of heritability of both direct and maternal effects obtained with DFREML were less than 1% and the genetic correlation between them was -.64. When survival of embryos from only those dams with 15 or more ovulations was analyzed, heritability of maternal effects was 4.4%. Estimates of common environmental effects on embryonic survival ranged from 5 to 7%.     

Increased transport of antarctic bottom water in the vema channel during the last ice age

Particle size analyses of surface sediments in the Vema Channel reveal a spatial variation related to the present hydrography. Similar analyses of sediment deposited during the last ice age (18,000 years before the present) indicate a maximum shallowing of the upper limit of Antarctic Bottom Water (AABW) of about 100 meters, coupled with an increase in velocity, which resulted in an increase in AABW transport.     

The long-term influence of past land use on the Walker Branch forest

Forest structure and composition influence patterns of insect outbreaks and can be explained on the Walker Branch watershed by past land use (timber harvest and agriculture), soils, aspect, and slope. In particular, pine bark beetles caused large losses of pine on sites that had been used for agriculture, on Fullerton silt loam soils, and on north-to-northeast and east-to-southeast exposures. Hickory bark beetles had a high impact on hickory biomass on Bodine soil areas that were forested in 1935 and sloped greater than 11%. Thus, prior land use can have an indirect effect on future disturbances.Because forest disturbances can affect nutrient distribution, land use can also indirectly affect nutrient availability. For example, locations of hickory bark beetle outbreaks experience a large flux of calcium from dead wood to soil because hickory accumulates large amounts of calcium in woody tissue. The research demonstrates a link between past land use, insect outbreaks, and calcium cycling.