日粮添加LA和DHA对乳脂脂肪酸含量及比值的影响

本试验选用带有永久性瘤胃、十二指肠和回肠瘘管的泌乳荷斯坦奶牛4头,采用4×4拉丁方试验设计,研究日粮添加亚油酸(LA)和二十二碳六烯酸(DHA)对乳常规组成、消化道各段食糜pH以及乳脂脂肪酸构成的影响.试验结果表明:添加LA和DHA不影响乳蛋白和乳糖含量(P>0.05),而添加DHA有显著降低乳脂含量的趋势(P>0.05);日粮共同添加LA与DHA能提高十二指肠前消化道的pH,但差异不显著(P>0.05),而单独添加DHA显著降低了回肠的pH(P<0.05);日粮单独添加DHA增加乳脂中C23:0脂肪酸的含量,但并不降低乳脂中总饱和脂肪酸量.与对照组相比,LA与DHA共同添加使乳脂中总多不饱和脂肪酸增加了100%(P<0.05).LA与DHA共同添加使乳脂中饱和脂肪酸/不饱和脂肪酸由3.18降低至1.24(P<0.05).添加DFIA使乳脂中总单不饱和脂肪酸/多不饱和脂肪酸由5.94降低至3.00(P<0.05).上述研究结果表明,日粮添加LA和DHA可改变乳脂中脂肪酸的组成和比例,有利于人体健康,但DHA使产奶量有一定程度的降低.     

膜上移栽机械研究进展及与分析

地膜覆盖技术与育苗移栽的结合能最大限度地提高部分经济作物蔬菜、烟草、中草药和棉花的品质和经济效益,而膜上移栽机械是实现上述农艺要求的核心装备。由于膜上移栽机械作业效率和稳定性问题,制约了膜上移栽机械的发展和推广。分别对国内和国外膜上移栽机械的结构、工作原理和特性进行了分析,探讨了国内膜上移栽机械发展的主要问题,指出膜上移栽机械的研制工作应着重实际应用,在农机与农艺结合的基础上,优化现有半自动移栽机的结构和性能,同时提高育苗技术,研制适合我国国情的、能够推广应用的全自动移栽机。     

Role and regulation of calcineurin in angiotensin Ⅱ-stimulated cardiac myocyte hypertrophy of rats

AIM: To study the role and regulation of calcineurin(CaN) in angiotensin II(AngⅡ)-stimulated cardiacmyocyte hypertrophy of rats. METHODS: Using AngⅡ to induce the cultured cardiac myocyte hypertrophy of rats, and investigating the effect of CaN inhibitor on [³H]-leucine incorporation of AngⅡ-stimulated cardiomyocytes and the regulation of various factors on CaN activity in cardiomyocytes.RESULTS: AngⅡ can stimulate the CaN activity in cultured neonatal rat cardiomyocytes in a dose- and time-dependent manner. In cardiac myocytes incubated with 10, 100, 1000 nmol·L^-1 of AngⅡ for 12h, the CaN activities increased respectively by 13%,57%(P＜0.05) and 228%(P＜0.01) compared with that in non-stimulated cardiomyocytes. The CaN activities in AngⅡ-stimulated cardiomyocytes were significantly inhibited by losartan(50 μmol·L^-1), H₇(50 μmol·L^-1)and Fura-2/AM(4 μmol·L^-1),while no effect was observed with PD98059(50 μmol·L^-1).The [³H]-leucine incorporation in AngⅡ-stimulated cardiomyocytes increased by 46%(P＜0.01) compared with that in control group, which was dramatically inhibited by cyclosporin A(0.5~5μg/mL). CONCLUSIONS: Calcineurin, a Ca²⁺/calmodulin-dependent protein phosphatase, may play an important role in AngⅡ-induced cardiac myocyte hypertrophy. The activation of CaN may dependent on the sustained increases of [Ca²⁺]i and be regulated by some protein kinases (such as PKC,etc.).     

Thermal and spectrophotometric analysis of some fungal melanins and soil humic compounds

Seven types of fungal melanins were compared with humic compounds from chernozem and podzol soils and with commercial humic acid. The results indicate some similarities but also distinct differences between the melanins and humic substances in spectral characteristics in the UV and visible regions and in their resistance to thermal degradation.     

Zur pedochemie des berylliums — untersuchungen einer bodengesellschaft im gebiet des bärhaldegranits (südschwarzwald)

The profile distribution of Be is given for a toposequence of podzols, brown earths, stagnogley, forest bog and “Ockererde” (slope gley with infiltrated Al, Mn and Fe). Analysed were the parent rock, fine earth, four fractions of mineral soil (fine skeleton, sand, silt, clay) and the needles of spruce trees.Beryllium is involved in selective weathering processes of elements. Accordingly, the Be-content increases from the fine skeleton to sand, rock, silt and clay, progressively. Through pedogenetic enrichment, Be accumulates in the mica-rich silt fraction.Uptake of Be by spruce is very low even from these acid soils. The accumulation in the needles becomes greater with increasing age.The pedochemical behaviour of Be is very similar to that of Al.Be is incorporated very little in the organic matter cycle, and is therefore not enriched in the soil humus.The brown earth has lost Be, especially in the A_h-horizon.In the A_e-horizon of the podzol, loss of Be is even greater; the loss is partly offset by Be-enrichment in the B-horizon.In the profiles of depressions, the Be-content is high and is ascribed to lateral flow from the slopes. Be-enrichment is especially high in horizons with a pH of about 5.The Be-balance of the watershed indicates an export of about 10% of the original amount.     

藜科杂草诱杀甜菜大龟甲初报

在甜菜田内利用灰藜等藜科杂草引诱发甜菜大龟甲成虫取食产物,然后集中消灭,减轻其对甜菜的危害,是一项可行措施。     

Habitat utilization and vertical movements of white marlin (Tetrapturus albidus) released from commercial and recreational fishing gears in the western North Atlantic Ocean: inferences from short duration pop-up archival satellite tags

Researchers have applied numerous techniques to improve billfish stock assessments, including habitat‐based models that incorporate behavioral and oceanographic parameters to standardize historical catch‐per‐unit‐effort time‐series data. These methods have allowed researchers to account for significant changes in the depths of pelagic longline (PLL) gear deployments over time. This study presents habitat‐use data recovered from high‐resolution 5‐ and 10‐day pop‐up satellite archival tags (PSATs) attached to 47 surviving white marlin released from commercial and recreational fishing gears offshore of the U.S. East Coast, the northern Caribbean, and Venezuela between 2002 and 2004. Data recovered from transmitting tags indicated that white marlin spent nearly half of their time associated with warm, near‐surface waters (<10 m). All fish displayed frequent short duration (mean: 39.8 min) vertical excursions from surface waters to depths averaging 51 m. Qualitative and multivariate classifications of data from completely transmitted movements of surviving white marlin revealed two major types of descents: one pattern was characterized by deep ‘V’‐shaped excursions of relatively short duration (mean: 23.4 min) while the other featured descents that were more broadly ‘U’‐shaped and confined to a specific depth range for an extended period of time (mean: 75.8 min). Based on the frequency, persistence, and patterns of these vertical movements, white marlin appear to direct a considerable proportion of foraging effort well below surface waters, a behavior that may account for relatively high catch rates of white marlin on some deep‐set PLL deployments.