Sterile soil from Antarctica: organic analysis

Soils from the dry-valley region of Antarctica can be sterile by the usual microbiological criteria and yet contain significant amounts of organic carbon. Examination of one such soil shows that the organic material is finely divided anthracite coal. These findings have significant implications for the biological exploration of Mars.     

Preliminary Study in Immature Canine Oocytes Stained with Brilliant Cresyl Blue and Obtained From Bitches with Low and High Progesterone Serum Profiles

This study was conducted: (i) to observe the features and levels of blue colour impregnation in morphologically selected immature canine cumulus oocyte complexes (COCs) stained with the brilliant cresyl blue (BCB) dye, as indicators of quality, and integrity of nuclear oocyte chromatin configuration before in vitro maturation (IVM); (ii) to observe the relationship between the influence of serum progesterone (SP) concentrations from ovary donors and BCB staining of immature dog oocytes. The results showed that out of 138 canine COCs, germinal vesicle (GV) stage prevailed in BCB+ oocytes at percentages of 67.4% (60/89), which were statistically higher than those observed in BCB+/− (52.2%; 23/44) and BCB− (20%; 1/5) oocytes (p = 0.023). Oocytes BCB+ were interpreted as those having completed their growth and therefore possessing the capacity to mature and develop in vitro . Ooplasm and cumulus cells (CCs) of canine oocytes were BCB staining independent. Ooplasm blue colour staining reaction varied between grown oocytes, revealing different levels of glucose-6-phosphate dehydrogenase activity among and within oocytes. Additionally, SP profile of ovary donors was not a relevant indicator for selection of oocytes screened with the BCB stain. Similar numbers of high quality oocytes were observed to be BCB+, BCB+/− and BCB− between groups of females with SP varying from 0 to 2.5 ng/ml (n = 5), and those with SP varying from 2.6 to 16.7 ng/ml (n = 4) (p = 0.680). It may be inferred that bitches with low and high SP profiles have grown oocytes in their ovaries, as determined by the BCB absorbance in their ooplasms.     

Effect of porcine somatotropin on in vivo glucose kinetics and lipogenesis in growing pigs.

Crossbred barrows were used for in vivo studies investigating hormonal regulation of lipogenesis. The first experiment examined an in vivo method for determining rates of lipogenesis. Three barrows were infused with [U-14C]glucose and incorporation of radioactivity into triglycerides was determined in up to five biopsies of subcutaneous adipose tissue obtained over 7 h. Incorporation was linear after blood glucose specific radioactivity had reached a plateau and was constant over the entire infusion. For the second experiment, eight pigs (71 +/- 2.5 kg) were allocated to one of two treatments involving daily injections of excipient (control) or porcine somatotropin (pST; 120 micrograms/kg of BW). On d 10, beginning 15 h after injection, glucose incorporation into adipose tissue lipid was determined under both basal and hyperinsulinemic/euglycemic conditions. Basal glucose incorporation into lipid, particularly fatty acids, was markedly reduced (greater than 90%) during pST treatment. Although glucose incorporation was increased to a similar extent in both groups by hyperinsulinemia, the pST-treated pigs still exhibited markedly lower rates. Based on kinetic data, the decrease in lipid accretion of pST-treated pigs was primarily the result of a decrease in the rate of de novo synthesis. Furthermore, the reductions in glucose incorporation into fatty acids, glucose irreversible loss rate, and feed intake that occur with pST treatment were quantitatively similar.     

Effect of extruded full-fat soybeans on conjugated linoleic acid content of intramuscular,intermuscular, and subcutaneous fat in beef steers

Crossbred Angus steers (n = 30) were used to determine whether the conjugated linoleic acid (CLA) content of beef fat could be increased by feeding varying levels of extruded full-fat soybeans as a source of polyunsaturated fatty acids for rumen biohydrogenation. Diets were as follows: 1) control, 2) 12.7% extruded full-fat soybeans (LESB), and 3) 25.6% extruded full-fat soybeans (HE SB). Steers were individually housed and fed the diets for 111 d during the finishing period. Over the experimental period, treatment groups were similar in ADG (1.7 +/- 0.1 kg/d) and had a similar slaughter weight (603 +/- 11.6 kg). Dressing percentage averaged 61.6% and carcass composition averaged 14.3% protein, 30.9% lipid, and 54.8% water. At slaughter, the intramuscular, intermuscular, and subcutaneous fat depots were sampled from the rib longissimus, eye of round, and chuck tender muscles. Across all fat depots, the CLA content differed (P < 0.05), averaging 6.6, 6.7, and 7.7 mg/g of fatty acids for the control, LESB, and HESB diets, respectively. There were significant differences in CLA content between fat depots within a cut, but differences were relatively small and the hierarchy in fat depots was not consistent among cuts. The cis-9, trans-11 isomer was the predominant CLA isomer and its content in fat was related to trans-11 C18:1 content (r = 0.53; P < 0.001). There was substantial individual variation in CLA content and this varied from 2.6 to 17.0 mg/g fatty acids across all treatments and fat depots. Overall, results demonstrated that including extruded full-fat soybeans in the diet of finishing steers increased the CLA content of beef fat. Differences were relatively small and the relationship of this to rumen fermentation and endogenous synthesis of CLA is considered.     

Effect of nutrient intake on the development of the somatotropic axis and its responsiveness to GH in Holstein bull calves

We investigated the effect of increasing nutrient intake on the responsiveness of the GH/IGF-I system in calves fed a high-protein milk replacer. Fifty-four Holstein bull calves were fed one of three levels (low, medium, and high; n = 18 per treatment) of a 30% crude protein, 20% fat milk replacer to achieve target rates of gain of 0.50, 0.95, or 1.40 kg/d, respectively, for low, medium, and high. Six calves per treatment were slaughtered at approximately 65, 85, and 105 kg BW. Additionally, six calves were slaughtered at 1 d of age to provide baseline data. Plasma aliquots from blood samples collected weekly were analyzed for IGF-I, insulin, glucose, NEFA, and plasma urea nitrogen (PUN). Plasma IGF-I and insulin, measured weekly, increased (P < 0.001) with greater nutrient intake from wk 2 of life to slaughter. Plasma glucose and NEFA also increased (P < 0.05) with nutrient intake. In addition, each calf underwent a GH challenge beginning 4 d before the scheduled slaughter. Plasma from blood collected before the first GH injection and 14 and 24 h after the third injection was analyzed for IGF-I and PUN. Response to challenge, calculated as the absolute difference between the prechallenge and 14-h postchallenge plasma IGF-I concentrations, was significant in calves on all three treatments. Plasma urea nitrogen was not different among treatments as measured weekly but decreased (P < 0.001) following GH challenge in all calves. Results of ribonuclease protection assays showed increased expression of hepatic mRNA for GH receptor 1A and IGF-I with increased intake. The amounts of GH receptor and IGF-I mRNA in muscle and adipose, however, were not affected by intake. In summary, plasma IGF-I was elevated in calves with increased nutrient intake, and the elevations in plasma IGF-I following short-term administration of GH were significant in all calves by 65 kg BW. Data demonstrate that in well-managed milk-fed calves the somatotropic (GH/IGF-I) axis is functionally coordinated and sensitive to nutrient intake and GH.     

Paratuberculosis on small ruminant dairy farms in Ontario,Canada: A survey of management practices

A cross-sectional study was undertaken (October 2010 to August 2011) to determine the risk factors for dairy goat herds and dairy sheep flocks testing positive for paratuberculosis (PTB) in Ontario, Canada. A questionnaire was administered to 50 producers during a farm visit in which concurrently, 20 randomly selected, lactating animals over the age of 2 years underwent sampling for paratuberculosis testing. Only 1 of 50 farms (2.0%) was closed to animal movement, whereas 96.6% of dairy goat farms and 94.1% of sheep farms purchased livestock from other producers. Only 10.3% of dairy goat, and no dairy sheep farms used artificial insemination. Manure was spread on grazing pastures by 65.5% and 70.6% of dairy goat and dairy sheep farms, respectively. Because of the high true-prevalence of paratuberculosis infection detected, no risk factor analysis could be performed. This study demonstrates that biosecurity practices conducive to transmission of PTB are highly prevalent in Ontario small ruminant dairy farms.     

C, N, and noble gas isotopes in grain size separates of presolar diamonds from efremovka

Nanometer-size presolar diamonds from the Efremovka CV3 chondrite were physically separated into several grain size fractions by ultracentrifugation. The coarsest size fraction is the most enriched in carbon-12; the others have broadly similar carbon isotopic compositions. Measurement of noble gases shows that their concentration decreases with decreasing grain size. This effect is attributed to ion implantation. Such an episode could occur in the envelope of a supernova that produced the diamonds, or in interstellar space; in either case, ions with energies above a certain threshold pass completely through the smaller diamond grains without being captured. Concentrations of nitrogen show only minor variations with grain size, indicating a different mechanism of incorporation into the diamonds.     

Principles for the use of macrocyclic lactones to minimise selection for resistance

OBJECTIVE: To provide principles for the appropriate use of avermectin/milbemycin or macrocyclic lactone (ML) anthelmintics in sheep, to ensure effective worm control and to minimise selection for ML resistance. STRATEGY: The principles were based on an assessment of the information currently available. The MLs were categorised into three groups (ivermectin [IVM], abamectin [ABA] and moxidectin [MOX]) based on structural differences, persistence and efficacy against ML resistant strains. The reported order of activity or efficacy against ML resistant worm strains was IVM相似文献