Fusarium solani Upregulated Sesquiterpene Synthase Expression,Sesquiterpene Production and Allelopathic Activity in Piper betle L.

Activators of sesquiterpene synthase (STS) gene expression and sesquiterpene production in Piper betle L. were examined using quantitative real time PCR and gas chromatography mass spectrometry methods, and the allelopathic activity of untreated and Fusarium solani-treated betel extracts was tested on seed germination and on the shoot and root growth of Thai rice variety PSL2 (Oryza sativa cv. Phitsanulok 2) and three dominant paddy weeds (Eclipta prostrata, Echinochloa crus-galli and Chloris barbata). The results demonstrated that F. solani dramatically upregulated STS expression and productions of β-cubebene, β-caryophyllene and germacrene D sesquiterpene when compared with the untreated control, and that betel extracts had a greater inhibitory effect on weeds than on rice. The effects were more clearly detected on seed germination and root growth than on shoot growth, and they were found to be dose-dependent. It is also noted that F. solani-treated extract had stronger effects than the untreated extract. The species most sensitive to the allelopathic effects was C. barbata, germination of which was completely inhibited even at a dose of 0.1 mg/mL untreated extract. With regards to rice, although betel extract at 1.0 mg/mL showed no inhibition on germination, it affected the elongation of rice roots, in addition to those of the tested weeds. The obtained data suggested that F. solani has potential as an activator of sesquiterpene allelochemical production via STS expression, the latter leading to the treated betel extract having a stronger phytotoxic effect. These results were beneficial in the promotion of natural herbicide production using biotechnology.     

Effects of N-methyl-D, L-aspartate on secretion of growth hormone-releasing hormone from the boar hypothalamic-preoptic area and median eminence in vitro

N-methyl-D, L-aspartate (NMA) elicited secretion of growth hormone (GH)-releasing hormone from both the hypothalamic-preoptic area and the median eminence that were collected from boars. We suggest that the previously described increase in GH secretion that follows peripheral treatment of swine with NMA is attributable, at least in part, to NMA-stimulated secretion of GH-releasing hormone from the central nervous system.     

Frozen bread dough: Effects of freezing storage and dough improvers

This review focuses on the effects of freezing storage on the microstructure and baking performance of frozen doughs, and provides an overview of the activities of dough improvers, including emulsifiers, hydrocolloids and other improvers used in frozen dough applications. The overall quality of bread baked from frozen dough deteriorates as the storage of the dough at sub-zero temperatures increases due to several factors which are discussed. Lipid-related emulsifiers such as diacetyl tartaric acid esters of mono and diglycerides and sucrose esters employed as anti-staling agents, dough modifiers, shortening sparing agents, and as improvers for the production of high-protein bread have also been employed in frozen doughs. Hydrocolloids are gaining importance in the baking industry as dough improvers due to their ability to induce structural changes in the main components of wheat flour systems during breadmaking steps and bread storage Their effects in frozen doughs is discussed. Other dough improvers, such as ascorbic acid, honey and green tea extract, are also reviewed in the context of frozen doughs.     

Stimulation of ROS-scavenging systems in squash (Cucurbita pepo L.) plants by compost supplementation under normal and low temperature conditions

The beneficial effect of compost, the final product of aerobic biodegradation of organic matter, on growth, lipid peroxidation [as malondialdehyde (MDA], hydrogen peroxide (H₂O₂) and superoxide anion (O₂^•−), activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), as well as reduced ascorbate (ASC) and glutathione (GSH) and their oxidized forms was investigated in squash (Cucurbita pepo L. cv. Eskandarany) plants exposed to normal and low temperature (LT) conditions. LT stress of 8 °C significantly reduced the plant growth of untreated plants, but compost alleviated the adverse effect of stress and significantly increased the fresh and dry weights under normal and stress conditions. LT also induced accumulation of H₂O₂ and O₂^•− and resulted in increased lipid peroxidation, pointing out to cellular oxidative stress. Under compost application, such reactive oxygen species (ROS) and peroxidized lipids were markedly reduced, but SOD, CAT, APX and GR activities, key enzymes of ROS-scavenging systems, were significantly increased. Data also indicated that there were general reductions in total ascorbate and glutathione pool in LT control plants, but compost-treated ones considerably have maintained higher levels of such redox metabolites. Significantly higher ratios of ASC/DHA (dehydroascorbate) and GSH/GSSG (glutathione disulfide) were generally found in compost-treated plants than in untreated-ones. It is evident that compost induced enhancement of LT tolerance was related to up-regulation of enzymatic and non-enzymatic antioxidant systems. Such enhancement would eventually protect plant cells from LT-induced oxidative stress reactions via scavenging ROS.     

Prolonged elevated atmospheric CO2 does not affect decomposition of plant material

Prolonged elevated atmospheric CO₂ might alter decomposition. In a 90-day incubation study, we determined the long-term (9 years) impact of elevated CO₂ on N mineralization of Lolium perenne and Trifolium repens plant material grown at ambient and elevated CO₂ and low- and high-¹⁵N fertilizer additions. No significant differences were observed in http://ars.els-cdn.com/content/image/1-s2.0-S0038071705001859-si4.gif"> recovery rates between any of the treatments, except an N addition effect was observed for L. perenne (0.4 versus 0.5% http://ars.els-cdn.com/content/image/1-s2.0-S0038071705001859-si5.gif"> day⁻¹ in high versus low N). The results suggest that elevated CO₂ did not change plant N mineralization in any of the soils, because of a surplus of available N in the fertilized and leguminous systems, and because of insignificant plant responses to elevated CO₂ in the low soil N availability systems.     

Nitrate uptake by Eriophorum vaginatum controls N2O production in a restored peatland

The clear dependence of N₂O production through denitrification on available nitrate http://ars.els-cdn.com/content/image/1-s2.0-S0038071705000350-si23.gif"> in soil has been shown in many studies. Since N availability similarly limits the growth of plants, the resource competition with vegetation limits the activity of denitrifying microbes and may consequently moderate the N₂O emissions from peatlands. We used http://ars.els-cdn.com/content/image/1-s2.0-S0038071705000350-si24.gif"> uptake by Eriophorum vaginatum L. as a vegetation competition factor for microbes. The species was selected for the experiment because it has high nutrient use efficiency in low-nutrient conditions and high nutrient uptake efficiency in luxuriant nutrient conditions. We measured gaseous N flux as N₂O (end product of denitrifier activity) in a restored peatland in central Finland with acetylene inhibition technique over a growing season from sample plots with varying http://ars.els-cdn.com/content/image/1-s2.0-S0038071705000350-si25.gif"> addition levels and E. vaginatum cover. The resource competition effects were analysed with a model that used exponential decay dependence of N₂O flux on the leaf area of E. vaginatum, and saturating response of N₂O flux to http://ars.els-cdn.com/content/image/1-s2.0-S0038071705000350-si26.gif"> addition level. The model explained the variation in N₂O fluxes well (R²=0.86). The model simulation showed that the increasing nutrient uptake of E. vaginatum decreased the N₂O fluxes exponentially. Simultaneously, denitrification appeared to saturate even in conditions with high availability of http://ars.els-cdn.com/content/image/1-s2.0-S0038071705000350-si27.gif"> and low level of competition by vegetation. Thus, E. vaginatum is an effective competitor for http://ars.els-cdn.com/content/image/1-s2.0-S0038071705000350-si28.gif"> in sedge-dominated peatlands that controls the availability of http://ars.els-cdn.com/content/image/1-s2.0-S0038071705000350-si29.gif"> for denitrification, and consequently moderates the N₂O emissions from peatlands.     

发挥第二课堂的作用培养学生创新素质和能力

笔者通过对创新能力和创新素质内涵的各种研究观点的总结分析,初步论述了大学生第二课堂目标的核心和实质。通过对高校大学生创新素质和能力以及创新实践活动的现状分析,提出了提升大学生第二课堂主阵地效能培养学生创新素质和能力的措施。     

Beyond electronic feeding: The implementation of call feeding for pregnant sows

Call feeding for pregnant sows is a novel modular extension of a conventional electronic feeder (PigTek INTEC MAC) communicating via ISOagriNET. The call feeding module (CFM) assigns individual calls to each animal of a group supplied by one feeder and trains them to associate that call with feed access. Afterwards it actively calls sows to the feeder in a variable sequence in order to minimize queuing and thereby reducing aggression, stress and injuries associated with feeding. In this paper, we describe the automatic training procedures, the principal technical design and implementation details that make call feeding applicable in practice. The automatic training consists of an initial Pavlovian conditioning during standard electronic feeding and a subsequent operant conditioning. During Pavlovian conditioning the sows may enter the feeder whenever they have remaining feed allowance. An individual acoustic signal is then played immediately before the feed is dispensed. In the operant training the sow learns by experience that she can enter the feeder only after the individual acoustic signal has been presented. The training modes and their durations are individual to each sow’s learning success. Undersupply with feed due to incomplete learning is prevented by the training routines without manual intervention by controlling automatically the proportion of operant and Pavlovian conditioning. Thus, introducing call feeding in an existing herd is possible. The implementation is further able to estimate roughly the social hierarchy and incorporates this in the calculation of the call sequence in order to attenuate feeding associated aggressions. It helps to provide the animals with a positive anticipation of safe feeding and thereby offers a suitable way to improve welfare and health of pregnant sows. Being automatically controlled, it is easy to apply and has the potential to become a promising future element of precision livestock farming.     

Nitrite production by Nitrosomonas europaea and Nitrosospira sp. AV in soils at different solution concentrations of ammonium

Although it remains unclear why NH₃-oxidizing bacteria (AOB) of the genus Nitrosospira dominate soil environments, and why Nitrosomonas spp. are less common, virtually no studies have compared their behavior in soil. In this study, the NH₃ oxidation rates of Nitrosomonas europaea (ATCC 19718) and Nitrosospira sp. AV were compared in three differently textured soils containing a range of extractable http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si32.gif"> contents (2-11 μg http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si33.gif"> soil). Soils were adjusted to pH 7.0-7.4 with CaCO₃ and sterilized with γ-radiation. Cell suspensions of each bacterium were inoculated into the soils to bring them to two-third of water-holding capacity and cell densities ∼2.5×10⁶ g⁻¹ soil. In virtually all cases, rates of http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si34.gif"> production for both N. europaea and Nitrosospira sp. AV were linear over 48 h, and represented between 13 and 75%, respectively, of the maximum rates achieved in soil-free bacterial suspensions. Soil solution http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si35.gif"> concentrations that supported these rates ranged between 0.2 and 1.5 mM. Addition of 21-36 μg http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si36.gif"> soil raised soil solution http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si37.gif"> levels to 1.8-2.5 mM and stimulated http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si38.gif"> production to a greater extent in N. europaea (3.3-6.6-fold) than in Nitrosospira sp. AV (1-2.1-fold). Maximum rates of http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si39.gif"> production were obtained by raising soil solution http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si40.gif"> levels to 3-4 mM with a supplement of ∼80-90 μg http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si41.gif"> soil. K_s values in soil for Nitrosospira sp. AV and N. europaea were estimated as 0.14 and 1.9 mM http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si42.gif">, respectively, and estimates of V_max were about 3.5-times higher for N. europaea (0.007 pmol h⁻¹ cell⁻¹) than for Nitrosospira sp. AV (0.002 pmol h⁻¹ cell⁻¹). The cell density of N. europaea increased in sterile Steiwer soil independent of supplemental http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si43.gif">. In the case of treatments receiving supplemental http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si44.gif">, growth yields of N. europaea calculated from either http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si45.gif"> produced or http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si46.gif"> consumed were similar to those reported in literature (3.5×10⁶-6×10⁶ cells μmol⁻¹http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si47.gif">). A higher growth yield was measured in the case of zero added http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si48.gif"> (2.7×10⁷ cells μmol⁻¹http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si49.gif">), indicating that use of organic carbon compounds might have occurred and resulted in some energy sparing. Our results suggest that Nitrosospira spp. with a K_s similar to Nitrosospira sp. AV may have an advantage for survival in soil environments where soil solution http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si50.gif"> levels are less than 1 mM. However, it is apparent that AOB like N. europaea are poised to take advantages of modest increases in extractable http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si51.gif"> that raise soil solution http://ars.els-cdn.com/content/image/1-s2.0-S003807170500297X-si52.gif"> levels to about 2.0-2.5 mM.