Effect of straw on the behaviour of growing pigs

The effects of straw on the behaviour of young growing pigs were studied in two experiments. In Experiment 1, groups of three pigs, aged about 7 weeks, were housed in raised decks with or without straw bedding. Time-lapse video recording showed no major differences between treatments in the amount or daily pattern of overall activity and feeding. Detailed observations showed that bedding reduced the incidence of rooting and chewing on pen-mates, but had little effect on other social activities such as mounting and aggressive biting. Experiment 2 compared groups of eight growing pigs aged about 10 weeks, housed in floor pens with or without a small amount of straw provided daily in a rack. Pigs with straw concentrated more of their daily activity into the period when straw was fresh, but the total amount of overall activity and time spent feeding were not affected. Rooting and chewing of pen-mates were the only social activities reduced by the provision of fresh straw. In these studies, where straw was not required to compensate for deficiencies such as low temperatures or hunger, the one major function of straw was to provide a stimulus and outlet for rooting and chewing, with a resulting reduction in such activities directed at pen-mates.     

Glucocorticoid, interleukin-2, and prostaglandin interactions in a clonal human leukemic T-cell line.

We have studied the growth effects of conditioned media, interleukin-2 and PGE prostaglandin analogs on the glucocorticoid-sensitive human leukemic T-cell clone, CEM-C7. After 4 days, the glucocorticoid dexamethasone at approximately 10 nM kills 50% of CEM-C7 cells. To test the hypothesis that glucocorticoid-mediated lymphocytolysis was due to suppression of lymphokine expression only, we attempted to protect CEM-C7 cells from lysis by provision of lymphokine(s). Conditioned media from interleukin-2 secreting Jurkat T-cells as well as the glucocorticoid-insensitive, but receptor positive clone, CEM-C1, failed to prevent lymphocytolysis; exogenous interleukin-2 also did not provide protection. There were complex, biphasic interactions between dexamethasone and the synthetic PGEs, enisoprost and enisoprost free acid. Low doses of enisoprost alone (0.01 to 1 microgram/ml) stimulated growth, and in combinations completely reversed the growth inhibitory effects of 10 nM dexamethasone. Higher concentrations of enisoprost were inherently lethal and were additive to the steroid effect. Thus the glucocorticoid-induced lymphocytolysis in this human leukemic T-cell line may be modified biphasically by PGE prostaglandins, depending on their concentration. However, interleukin-2 or components in the conditioned media assayed had no effect in ameliorating the lethal response to glucocorticoid.     

Effect of dexamethasone on nucleolar casein kinase II activity and phosphorylation of nucleolin in lymphosarcoma P1798 cells.

Ribosomal RNA (rRNA) synthesis in murine P1798 lymphosarcoma cells is reversibly inhibited by glucocorticoids. The effects of dexamethasone upon nucleolin phosphorylation and upon the amount and activity of casein kinase II have been examined. P1798 cells were exposed to 0.1 microM dexamethasone for 36 h. Cells were labeled in vivo with [32P]orthophosphate followed by immunoprecipitation with anti-nucleolin antibody. Nucleolin phosphorylation was reduced by 60% in dexamethasone-treated cells. Nucleoli were isolated and labeled with [gamma-32P]ATP in vitro. Nucleolin protein was reduced to 40% of control in nuclei from dexamethasone-treated cells. Nucleolin phosphorylation was reduced to 20% of control. Nucleolar casein kinase II activity and protein were also reduced (30-55% and 35-50% of control, respectively) by treatment with dexamethasone. Cycloheximide (10 micrograms/ml for 3 h) reduced the amount and activity of casein kinase II, but did not cause a decrease in nucleolin protein. These observations are discussed relative to the hypothesis that glucocorticoids regulate the amount or activity of proteins of short biological half-life that are involved in the regulation of rRNA synthesis.     

Molecular cloning in Lactobacillus helveticus by plasmid pSA3::pVA797 co-integrate formation and conjugal transfer

Summary A gene encoding -glucanase activity from Bacillus amyloliquefaciens was subcloned in both orientations into plasmid shuttle vector pSA3. In only one orientation could a co-integrate be generated with the conjugative plasmid pVA797. The plasmid co-integrate was conjugated into Lactobacillus helveticus strain CNRZ450, where it was stably maintained without antibiotic selection and exhibited -glucanase activity. This method of introducing cloned DNA into thermophilic lactobacilli will facilitate the study of heterologous gene expression in non-transformable species. Offprint requests to: J. K. Thompson     

EMG muscle scanning: comparison to attached surface electrodes.

Electromyographic (EMG) muscle scanning measures brief samples of integrated muscle action potentials from individual muscles using a hand-held scanner with post-style electrodes. This "scanning" technique is widely used by biofeedback practitioners to quickly assess muscle activity in the diagnosis of musculoskeletal disorders. In an effort to compare muscle scanning with the established technique using attached surface electrodes, ten healthy subjects (25-35 years old) were scanned using 2-second sampling at five bilateral muscle sites while simultaneously monitoring the same sites with surface electrodes. This was repeated using 10-second scanning samplings. Pearson's product-moment correlations between scanning for 2 seconds and prolonged surface recording at all sites were 0.54-0.89. Scanning for 10 seconds improved the correlations to 0.68-0.91. EMG scanning for 2 seconds compares favorably with attached surface electrode recording. Comparisons are further improved by 10-second scans.     

Human creatine kinase genes on chromosomes 15 and 19, and proximity of the gene for the muscle form to the genes for apolipoprotein C2 and excision repair.

The human chromosomal assignments of genes of the creatine kinase (CK) family--loci for brain (CKBB), muscle (CKMM), and mitochondrial (CKMT) forms--were studied by Southern filter hybridization analysis of DNAs isolated from a human x rodent somatic cell hybrid clone panel. Probes for the 3'-noncoding sequences of human CKBB and CKMM hybridized concordantly only to DNAs from somatic cell hybrids containing chromosomes 14 and 19, respectively. Thus the earlier assignment of the gene coding for the CKBB isozyme to chromosome 14 was confirmed by molecular means, as was the provisional assignment of CKMM to the long arm of chromosome 19. A probe containing canine sequences for CKMM cross-hybridized with human sequences on chromosomes 14 and 19, a result consistent with the assignments of CKBB and CKMM. A probe containing human sequences for CKMT enabled the provisional assignment of CKMT to human chromosome 15. Independent hybrids with portions of the long arm of chromosome 19 missing indicated the order of genes on the long arm of chromosome 19 as being cen-GPI-(TGFB, CYP1)-[CKMM, (APOC2-ERCC1)]-(CGB, FTL). The unexpectedly more distal location of APOC2 among the genes on the long arm--and APOC2's close association with CKMM--is discussed with respect to the close linkage relationship of APOC2 to myotonic muscular dystrophy.     

Regulation of carbon and electron flow in Propionispira arboris: relationship of catabolic enzyme levels to carbon substrates fermented during propionate formation via the methylmalonyl coenzyme A pathway.

A detailed study of the glucose fermentation pathway and the modulation of catabolic oxidoreductase activities by energy sources (i.e., glucose versus lactate or fumarate) in Propionispira arboris was performed. 14C radiotracer data show the CO2 produced from pyruvate oxidation comes exclusively from the C-3 and C-4 positions of glucose. Significant specific activities of glyceraldehyde-3-phosphate dehydrogenase and fructose-1,6-bisphosphate aldolase were detected, which substantiates the utilization of the Embden-Meyerhoff-Parnas path for glucose metabolism. The methylmalonyl coenzyme A pathway for pyruvate reduction to propionate was established by detection of significant activities (greater than 16 nmol/min per mg of protein) of methylmalonyl coenzyme A transcarboxylase, malate dehydrogenase, and fumarate reductase in cell-free extracts and by 13C nuclear magnetic resonance spectroscopic demonstration of randomization of label from [2-13C]pyruvate into positions 2 and 3 of propionate. The specific activity of pyruvate-ferredoxin oxidoreductase, malate dehydrogenase, fumarate reductase, and transcarboxylase varied significantly in cells grown on different energy sources. D-Lactate dehydrogenase (non-NADH linked) was present in cells of P. arboris grown on lactate but not in cells grown on glucose or fumarate. These results indicate that growth substrates regulate synthesis of enzymes specific for the methylmalonyl coenzyme A path and initial substrate transformation.     

Asymmetry of lysophosphatidylcholine/cholesterol vesicles is sensitive to cholesterol modulation

Sonication of lysophosphatidylcholine (lysoPC; 20 mumol/mL) and cholesterol (chol) in aqueous medium produces lamellar structures over a wide range of concentrations. From 25 to 47 mol % cholesterol, electron microscopy (EM) after negative staining showed extended stacklike lamellae about 40 A thick. From 50 to 60 mol % chol, freeze-fracture EM showed homogeneous populations of small unilamellar vesicles averaging 260-310 A in diameter. Phosphorus-31 nuclear magnetic resonance was used to characterize the stacklike lamellae and to measure the distribution of the lysophospholipid between the outer and inner leaflet of the vesicles as a function of sterol concentration. We found that in lysoPC/chol dispersions containing less than equimolar amounts of cholesterol (25-47 mol %), the entire phosphorus signal (40.5 ppm) was shifted downfield by 10.5 ppm upon addition of Pr3+ (2.4 mM), consistent with the stacklike lamellar structures in which all lysoPC head groups are accessible to the ions. By contrast, addition of Pr3+ to lysoPC/chol vesicles containing equimolar or higher amounts of cholesterol (up to 60 mol %) gave rise to two phosphorus peaks. The more intense downfield signal (51.0 ppm) responsive to paramagnetic ions was assigned to lysoPC located in the outer vesicle leaflet. The upfield signal (40.5 ppm), which was not affected by the ions, was assigned to inside lysoPC. For lysoPC/chol (1:1) vesicles, an outside to inside lysophospholipid ratio (Ro/i) of 6.5 was determined. Essentially the same Ro/i value (6.7) was obtained on lysoPC/chol (1:1) vesicles which after dialysis contained only entrapped Pr3+.(ABSTRACT TRUNCATED AT 250 WORDS)