Interactions betweenKalmia and black spruce: Isolation and identification of allelopathic compounds

Aqueous extracts of fresh leaves and organic soil of northern sheep laurel (Kalmia angustifolia var.angustifolia) were found to be inhibitory to the growth of black spruce (Picea mariana) germinants. Primary root growth of black spruce was more affected by the extracts than was shoot growth. The growth inhibition caused by the leaf extract was most pronounced under acidic conditions (pH 3–4). The aqueous extract ofKalmia leaves contained ferulic, vanillic, syringic, gentisic,m-coumaric,p-coumaric,o-hydroxyphenylacetic, andp-hydroxybenzoic acids as well as some other unknown compounds. These compounds were isolated from the aqueous extract ofKalmia leaves by ethyl acetate extraction and identified using thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). Bioassay indicated that the overall toxicity of the phenolic compounds to black spruce appeared to increase in the order ofo-hydroxyphenylacetic,p-hydroxybenzoic, vanillic,p-coumaric, gentisic, syringic, ferulic, andm-coumaric acids.     

Computer-assisted stereology: point fraction of lung parenchyma and alveolar surface density in fetal and newborn sheep

The aim of this study was to determine the accuracy of a new computer-assisted stereological technique in obtaining structural information of the lung. We compared the point fraction of lung parenchyma (Pp) and alveolar surface density (Sv) obtained by established manual point/intercept counting methods and compared them with those obtained using a computer-assisted method. Lung tissues obtained from normally grown fetal sheep (n = 6) and from newborn lambs with severe lung hypoplasia (n = 5) were inflation fixed via the trachea and processed for light microscopy. In verification-of-technique experiments, Pp and Sv correlated well with known values. There was a significant linear correlation between manual and computer-assisted stereological measurements for values of Pp (r2 = 0.92) and Sv (r2 = 0.98). Our data lead us to believe that the computer-assisted stereological technique described in this study provides accurate estimates of Pp and Sv and hence may be a valuable tool for evaluating the effects of factors upon structural development of the lung.     

Modifications in chromatin morphology and organization during sheep oogenesis

This research has been designed to study the major events of nuclear remodeling that characterize sheep oocytes during the early stage of folliculogenesis (transition from preantral to antral stage). In particular, the modifications in large-scale chromatin configuration, the global DNA methylation, and the process of telomere elongation have been investigated as crucial events of oocyte nuclear maturity. In addition, the spatio-temporal distribution of the major enzymes involved in DNA methylation, the DNA methyltransferase 1 (Dnmt1), and in telomere elongation, telomerase catalytic subunit (TERT), have been described. To these aims, the nuclei of isolated oocytes were investigated using immunocytochemistry and Q-FISH analyses. In absence of preliminary information, these nuclear determinants were compared with those of fully competent germ cells obtained from medium and preovulatory antral follicles. The nuclei of sheep oocytes acquired a condensed chromatin configuration, stable high levels of global DNA methylation, and a definitive telomere length already in the majority of late growing stage oocytes (110 microm) derived from early antral follicles. In addition, while the process of methylation resulted strictly related to oocyte diameter, the telomeric program appeared to be highly chromatin configuration-dependent. The translocation of Dnmt1 and TERT from the nucleus to the cytoplasm in the oocytes derived from early antral follicles seems to confirm the definitive chromatin asset of these germ cells. In conclusion, changes in large-scale chromatin structure, epigenesis, and telomere size in the sheep are established prior to oocyte acquires the ability to resume meiosis.     

Effects of predator fecal odors on feed selection by sheep and cattle

The effectiveness of predator fecal odors in modifying feeding selection by sheep and cattle was investigated in two trials. In trial 1, animals could select from feed bins contaminated with coyote, fox, cougar, or bear fecal odor, and oil of wintergreen, or select the control feed. All odors were rejected (P<0.01) by sheep and cattle, except bear odors by sheep. In trial 2, animals could select feed during 10-min periods in an open 11-m × 16-m arena. Fecal odor did not influence approaches to feed bins, or head entries into bins. Only coyote fecal odor reduced (P<0.05) the time spent feeding in the contaminated bin, and increased (P<0.05) consumption from the control bin by both cattle and sheep. Some animals on some test days refused to feed from either feed bin, although cattle and sheep closely inspected bins. Results suggest that fecal odors may not prevent livestock from entering a treated area but may reduce the time spent grazing in such an area.This research was supported in part by the Utah Agric. Exper. Sta., Utah State University, Logan, Utah 84322. Approved as journal article no. 3721     

Appraisal process in sheep (Ovis aries): Interactive effect of suddenness and unfamiliarity on cardiac and behavioral responses.

Appraisal theories state that an emotion results from an individual's evaluation of a stimulating event, which is based on a set of criteria. Each criterion triggers specific expressions that can be modulated by the outcome of other criteria. The authors analyzed the effects of the criteria of suddenness, unfamiliarity, and their combination on behavioral and cardiac responses in lambs (Ovis aries). Lambs were exposed to a visual stimulus that appeared either rapidly or slowly and was either unfamiliar or familiar. Suddenness induced a startle response and an increase in heart rate. Unfamiliarity induced an orientation response. The combination of suddenness and unfamiliarity enhanced both the heart rate increase and the behavioral orientation response. These results support the hypotheses of specificity and modulation of emotional expressions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How herbivores track variable environments: Response to variability of phytotoxins

The concentration of toxins in plants can vary with plant phenology and environmental factors. Changes in toxicity may or may not be associated with changes in plant flavor. These factors may make it difficult for herbivores to avoid toxic plants. We conducted three experiments concerning animals' ability to detect toxins. In experiment 1, we examined whether animals familiar with a tastable toxin on food would adjust intake when toxin concentrations changed. Lambs were initially offered oats with either a low, medium, or high concentration of lithium chloride (LiCl; a salty-tasting toxin). Later, when all lambs were offered oats with the medium concentration of LiCl, lambs that were conditioned with the low LiCl concentration decreased intake while lambs conditioned with the high LiCl concentration increased intake. In experiment 2, we examined flavor aversions formed when animals sampled food with two flavor levels prior to illness. Lambs initially ate the same amount of barley with a low and with a high concentration of either sodium saccharin (a sweet flavor) or aluminum sulfate (a bitter flavor). Lambs then received a mild dose of LiCl. Later, when lambs were offered a choice between barley with either a low or high flavor concentration, lambs preferred the barley with the low flavor concentration. Experiment 3 examined how variable toxicity affected intake when the flavor remained constant. Lambs were initially offered oregano-flavored barley and then received a dose of LiCl. Lambs received either a medium dose, a high dose, or a dose that varied randomly among low, medium, or high amounts of LiCl. Lambs in the medium dose group ate more oregano-flavored barley at the end of the trial than did lambs in either of the other groups.This research was supported by the Utah Agricultural Experiment Station, Utah State University, Logan, Utah 84322. Approved as journal paper No. 4337. The research methods were approved by the Animal Care and Use Committee at Utah State University.     

铬鞣绵羊皮辐射接枝丙烯酸丁酯的成革性能

脱灰裸皮和铬鞣绵羊皮在~(60)Co-γ射线引发下,能与丙烯酸及丙烯酸丁酯发生接技共聚反应,我们曾报道过通过测定氮含量、茚三酮显色试验和红外光谱分析得以确证。本文报道云贵路绵羊皮辐射接技丙烯酸丁酯的成革性能。 云贵路绵羊皮皮板瘦薄,痘疔、癣癞及伤残较多,毛孔大,粒面粗糙,部位差异大,是国内最次的原料皮。用这种低档原料皮来生产中、高档服装手套革显然是困难的。成革等级     

Analytical characterisation and production of wool wax from Akkaraman and Morkaraman sheep's wool

The analytical characterisation and production of wool wax from Akkaraman and Morkaraman sheep in the East Anatolien region of Turkey have been investigated. It was shown that the analytical characteristics of Akkaraman and Morkaraman wool waxes differ only slightly from other wool waxes. Therefore, from a quality point of view, wool waxes obtained from this work can be used for the same purposes as wool waxes produced from different varieties of sheep.     

Effects of nitrogen and sulphur fertilization on oats yield, quality and digestibility and nitrogen and sulphur metabolism of sheep in the Inner Mongolia Steppes of China

The influence of nitrogen (N) and sulphur (S) fertilizer on yield and quality of spring oats and the N and S metabolism of sheep was determined. Eighteen crossbred wether lambs (about 30 kg) were fed oats fertilized with N (0, 138 kg N/ha as of urea) and S (0, 30 and 60 kg S/ha as gypsum) assigned randomly to six treatments in an experiment of 2×3 factorial design. On S-deficient soils, S and N fertilization increased dry matter (DM) by 10.5 and 71.9%, and crude protein (CP) yield of oats by 11–13 and 94.5%, but there was no interaction between N and S fertilizer. S fertilization increased S content of oats from 0.14 to 0.29% and significantly reduced the N:S ratio from 14.4 to 7.22. There was a significant interaction between N and S on N content. N and S fertilization significantly increased apparent DM digestibility of oats by about 4%, but did not affect intake (g/kg BW^0.75), DM intake being almost 60 g/kg BW^0.75 for all treatments. N increased average daily gain of lambs by 62.4–78.6% if S was supplied, being twice the gain without S supply but no interaction between N and S was observed. N retention was affected by interaction between N and S fertilization. N retention and N utilization were positively correlated with S intake. N:S ratio in oats was positively correlated with N metabolism. S fertilization increased N utilization efficiency and vice versa. The critical levels of total S in oats were 0.20 and 0.23%, and the critical levels of N:S ratio were 17.0 and 15.7 for maximum DM and CP yield, respectively. The critical levels of S content and N:S ratio for maximum average daily gain of lambs were 0.26% and 10.5, respectively. Therefore, in the diagnosis of S status in soil–forage–animal systems, the use of total S and N:S ratio in the forage tops for the maximum CP yield is preferable to that for the maximum DM yield because the values are more closely related to the requirements for maximum daily gain of lambs; similarly, the use of a combination of total S and N:S ratio is preferable to the use of N:S ratio alone.     

羊脾脏提取液抗氧化作用的研究

在卵黄脂蛋白过不饱和脂肪酸过氧化体系、亚油酸过氧化体系中研究了羊脾脏提取液的抗氧化活性。实验表明；羊脾脏提取液在以上体系中均表现出抗氧化活性，但其活性与实验体系密切相关；脾脏提取液中主要抗氧化活性物质的分子量在10万以上，推测可能是蛋白质或酶；所表现的抗氧化活性是多种成分协同作用的结果。