A field evaluation using the 15N isotope dilution method of lines of Phaseolus vulgaris L. bred for increased nitrogen fixation

N₂ fixation in lines of Phaseolus vulgaris was measured by ¹⁵N-isotope dilution to determine whether a programme of crossing and recurrent selection had resulted in enhanced nitrogen fixation. In field experiments on an isohyperthermic Aquic Hapludoll soil the amount of N₂ fixed by the different lines ranged from 18 to 36 kg ha^–1 (32 to 47% of plant N) in 56 days. The quantity of N₂ fixed and the proportion of plant N derived from fixation was not significantly greater in the lines selected for N₂ fixation (RIZ lines) than parental lines. Total shoot N ranged from 53 to 77 kg ha^–1 and partitioning of N to pods differed from 28 to 52% among the lines which all had similar growth habit and duration. Nodulation patterns were also distinct. Nodules formed early (10 to 15 plant^–1 at 13 days) in many lines, and smallest amounts of fixation were observed in those lines which nodulated slowly and did not form substantial nodule mass until after 40 days. The screening criteria used in the selection of the RIZ lines had been largely indirect with other factors such as disease resistance also being included. Progress for increasing N₂ fixation over good-fixing parental lines such as BAT76 was not significant and it is recommended that more attention be paid to early nodulation, to the use of soils with lower available N and to inter-crossing of lines having different good N₂ fixation traits in order to further enhance the potential for N₂ fixation in beans.     

Incorporation of atmospheric 15NO2-nitrogen into free amino acids by Norway spruce Picea abies (L.) Karst.

During spring and autumn 1991, potted 6-yearold spruce trees (Picea abies (L.) Karst.) were fumigated with 60 nl·1^{–1 15}NO₂ for 4 days under controlled conditions in constant light. Current and previous flush needles, the bark and the fine roots were analysed for total ¹⁵N content and incorporation of ¹⁵N into the -amino nitrogen of free amino acids. In addition, in vitro nitrate reductase activity and stomatal conductance of the needles were measured. Nitrate reductase activity was significantly higher in the needles of fumigated trees compared to control trees exposed to filtered air. With an average of 9.1% ¹⁵N, free glutamate was the pool with the most label. Taking into account the time-course of the labelling of this pool, this figure can be taken as an estimate of the minimum contribution of NO₂ to the N nutrition of the needles. ¹⁵N-labelled amino acids were also detected in the bark and the roots, indicating export from the needles.     

Overview of growth differentiation factor 15 in metabolic syndrome

Growth and differentiation factor 15 (GDF15) is a member of the transforming growth factor-β (TGF-β) superfamily. GDF15 has been linked with several metabolic syndrome pathologies such as obesity and cardiovascular diseases. GDF15 is considered to be a metabolic regulator, although its precise mechanisms of action remain to be determined. Glial cell-derived neurotrophic factor family receptor alpha-like (GRAL), located in the hindbrain, has been identified as the receptor for GDF15 and signals through the coreceptor receptor tyrosine kinase (RET). Administration of GDF15 analogues in preclinical studies using various animal models has consistently been shown to induce weight loss through a reduction in food intake. GDF15, therefore, represents an attractive target to combat the current global obesity epidemic. In this article, we review current knowledge on GDF15 and its involvement in metabolic syndrome.     

Production of trichothecene mycotoxins byFusarium graminearum andFusarium culmorum on barley and wheat

Wheat cultivars (Stoa, MN87150, SuMai-3, YMI-6, Wheaton) and barley cultivars (Robust, Excel, Chevron, M69) were inoculated in the field with isolates ofFusarium graminearum andF. culmorum. The diseased (Fusarium head blight) kernels were analyzed for deoxynivalenol (DON), 15-acetyldeoxynivalenol (15-ADON) and nivalenol (NIV).F. culmorum produced all three trichothecenes on all cultivars tested whereasF. graminearum only produced DON and 15-ADON. There was no well defined correlation between DON production in the host and resistance although the data tended to favor SuMai-3 as having definitive resistance to bothF. graminearum andF. culmorum.Minnesota Agricultural Experiment Station, Paper No. 20 279.     

15N abundance of soils and plants along an experimentally induced forest nitrogen supply gradient

¹⁵N abundances of soils and a grass species (Deschampsia flexuosa (L.) Trin.) were analysed in a forest fertilization experiment 10 years after the last fertilization. Nitrogen had been given as urea, at seven doses, ranging from 0 to 2400 kg N ha^-1. Previously, we have shown that plants in systems experiencing large losses of N become enriched with ¹⁵N. This was explained by the fact that processes leading to loss of N, e.g. ammonia volatilization, nitrification followed by leaching or denitrification and denitrification itself, tend to fractionate against ¹⁵N. In this experiment, ¹⁵N abundance increased with dose of N applied in both grass and soil total-N, but more so in the grass. This was interpreted to be due to the grass sampling small but active pools of N subject to losses. In contrast, soil total-N largely consists of inactive N that does not immediately exchange with pools of N from which fractionating losses occur. Hence, soil total-N shows a large pretreatment ¹⁵N memory effect, and is, therefore, and integrator of the long-term N balance. When short-term changes (years, decades) in N balances are monitored using variations in ¹⁵N abundance, plants are more suitable indicators of such change than is soil total-N.     

稻田土壤－作物－家畜系统中氮的循环研究

本文用Ｎ＾１５标记水稻和绿肥研究了稻田土壤－作物－家畜系统中氮的循环。Ｎ＾１５标记稻草喂羊,羊体回收饲料稻草Ｎ３１．１６％,羊粪２８．２６％,羊尿５．７２％,总回收６５．１４％,损失３４．８６％。将羊粪尿单施,稻谷回收饲料稻草Ｎ３．１９％,水稻全株回收４．８２％,水稻全株回收４．８２％,土壤残留１９．００％,损失１０．１４％。故羊体,水稻及土壤残留共回收饲料稻草Ｎ５４．９８％。将羊粪与尿素配施,则     

Gdf15对酒精性脂肪肝代谢异常的影响

摘要 目的：探讨生长分化因子15（Growth and Differentiation Factor 15, GDF15）对于酒精性脂肪肝(alcoholic fatty liver, AFL)代谢异常的影响。方法：用白酒构建酒精性脂肪肝小鼠模型然后分别给对照组和模型组尾静脉注射AAV8-GDF15过表达肝脏的GDF15分子,将小鼠共分为四组：正常+尾静脉注射对照AAV8-NC组(Con+AAV8-NC)、模型(酒精)+尾静脉注射AAV8对照病毒组(AFL+AAV8-NC)、正常+尾静脉注射过表达AAV8-Gdf15组(Con+AAV8-Gdf15)、酒精+尾静脉注射过表达AAV8-Gdf15组(AFL+AAV8-Gdf15)。对其体重、空腹血糖、葡萄糖耐量、胰岛素释放、血清脂、肝脏脂、谷丙转氨酶、谷草转氨酶含量的测定;其肝脏活组织切片使用苏木精-伊红染色法染色检测肝脏结构异常;q-PCR检测脂代谢相关分子RNA水平等观察过表达GDF15对酒精性脂肪肝的影响。结果：与Con+AAV8-N组相比,AFL+AAV8-NC组的体重下降,而过表达GDF15后AFL+AAV8-Gdf15组体重比AFL+AAV8-NC组的体重下降减少。与Con+AAV8-NC组相比,AFL+AAV8-NC组的空腹血糖升高、糖耐量及胰岛素耐量下降,过表达GDF15后AFL+AAV8-Gdf15组与AFL+AAV8-NC相比空腹血糖显著下降、糖耐量及胰岛素耐量显著升高。AFL+AAV8-NC组与Con+AAV8-NC组相比血脂TG明显升高,过表达GDF15后AFL+AAV8-Gdf15组血脂与AFL+AAV8-NC的血脂相比显著下降。与Con+AAV8-NC组相比,AFL+AAV8-NC组的肝脏重量增加,肝功能损伤程度更严重,肝脏脂肪含量增加,而过表达GDF15后AFL+AAV8-Gdf15与AFL+AAV8-NC组相比,肝脏重量、损伤程度及肝脏的脂肪含量均有显著性下降。结论：酒精性脂肪肝增加GDF15的表达,而GDF15的表达增加会改善酒精性脂肪肝的损伤及代谢异常。     

Evaluation and control of the nutritional status of cereals

Summary A quantitative therapy method was developed for predicting and controlling grain yields of oats and spring wheat based on methods of diagnosis and yield pronosis and on effects of supplementary applications of nutrients on the chemical composition of the young plant at a fixed Dry Matter weight-level.The characteristic interactions integrated in the models of therapy and depending on kind, source, amount and combination of the nutrient applications on the chemical composition of the young plant allow selection of the best possible nutrient therapy under the given circumstances.The therapy method, tested by comparing predicted with experimentally obtained nutrient concentrations in the young plant, was proved reliable by the high and highly significant correlation coefficients (r>0.9;p<0.001). The correctness of the basic concepts underlying the therapy method, was thus indirectly confirmed and the possibility to use the method in agricultural practice would appear promising.     

Proliferating cells in histiocytic necrotizing lymphadenitis

The phenotypes of proliferating cells in histiocytic necrotizing lymphadenitis (HNL) were examined. The affected areas consisted mainly of CD 8-positive (suppressor/cytotoxic T-cells) and CD 4-positive (helper/inducer T-cells) in association with some CD 15-positive cells (monocytes). A marker of proliferating cells (Ki-67) and monoclonal antibodies for determining the phenotypes of cells (CD 4, CD 8, CD 15) in the affected areas were applied using a double-staining method. Ki-67-positive proliferating cells were mainly CD 8-positive. A few CD 4-positive cells and rare CD 15-positive cells were also Ki-67-positive. The percentage of CD 8-positive cells increased gradually over time and the ratio of CD 8-positive to proliferating cells did not decrease throughout the observation period of 6 weeks. These results suggest that the proliferation of CD 8-positive T-cells together with the accumulation of CD 4- and CD 15-positive cells is the main phenomenon occurring in HNL.     

Opiate-Dependent Changes in the Sensitivity of Adenylate Cyclase to Stimulatory Agonists and 5''-Guanylylimidodiphosphate Are Independent of G Protein Abundance and Eukaryotic ADP-Ribosyltransferase Activity in NG108-15 Cells

NG108-15 cells were exposed in culture to 1 microM [D-Ala2,D-Leu5]enkaphalin (DADLE) for 17 h. This treatment increased the maximum iloprost- and 5'-(N-ethylcarboxamido)adenosine-dependent activation of adenylate cyclase, as well as basal enzyme activity. In addition, there was an increase in the capacity of 5'-guanylylimidodiphosphate [Gpp(NH)p] to inhibit adenylate cyclase activity by direct interaction with the alpha-subunit of the Gi regulatory protein. A similar effect was observed if the cells were exposed to 10 microM carbachol. These treatments of NG108-15 cells did not alter the capacity of NaF to activate adenylate cyclase by direct interaction with Gs alpha. Exposure of NG108-15 cells to DADLE alone or DADLE plus carbachol had no effect on the capacity of pertussis toxin to ADP-ribosylate membrane proteins in these cells; neither was there any change in the activity of eukaryotic ADP-ribosyltransferase expressed in these cells. Under these conditions, the endogenous enzyme did not label any protein with a molecular mass similar to Gi alpha, 41 kDa. Treatment of the cells with DADLE or carbachol had no effect on the abundance of Gs alpha, Gi alpha, or G beta. The underlying mechanism for the changes in agonist-dependent stimulatory responses or Gpp(NH)p-dependent inhibition of adenylate cyclase remains obscure, but appears not to be mediated by eukaryotic ADP-ribosyltransferase activity or a change in the abundance of G proteins known to regulate adenylate cyclase.