Plant growth and microbial activity in a tropical soil amended with faecal pellets from millipedes and woodlice

The effect of soil fauna-mediated leaf litter (faecal pellets) versus mechanically fragmented (finely ground) leaf litter on biomass production of rice (Oryza sativa, var. Primavera) was assessed in pot tests. Rice seedlings were either grown in soil samples amended with faecal pellets of diplopods and isopods fed on leaf litter of a legume cover crop (Pueraria phaseoloides (Roxb.) Benth) and a peach palm (Bactris gasipaes) or in soil amended with finely ground leaf litter. The addition of faecal pellets caused a significant and dose-related increase in plant biomass compared to pure soil. Ground leaf litter induced a significantly smaller positive effect on plant biomass development with Pueraria litter > Bactris litter > mixed primary forest litter. In contrast, soil microbial biomass development during the 4 weeks plant test was higher in the soil amended with ground litter as compared to soil amended with feacal pellets. The results show a clear positive effect of the soil fauna on soil fertility and indicate differences in the availability of nutrients from the organic substrates to higher plants and soil microorganisms.     

Synaptic plasticity in spinal lamina I projection neurons that mediate hyperalgesia

Inflammation, trauma, or nerve injury may cause enduring hyperalgesia, an enhanced sensitivity to painful stimuli. Neurons in lamina I of the spinal dorsal horn that express the neurokinin 1 receptor for substance P mediate this abnormal pain sensitivity by an unknown cellular mechanism. We report that in these, but not in other nociceptive lamina I cells, neurokinin 1 receptor-activated signal transduction pathways and activation of low-threshold (T-type) voltage-gated calcium channels synergistically facilitate activity- and calcium-dependent long-term potentiation at synapses from nociceptive nerve fibers. Thereby, memory traces of painful events are retained.     

生物有机垃圾厌氧消化制取甲烷的研究

[目的]倡导垃圾分类的新理念。[方法]在37℃条件下对沈阳市源分类后城市生物有机垃圾进行为期50 d批消化处理试验。[结果]结果表明:沈阳市皇姑区和东陵区示范小区城市生物有机垃圾厌氧消化沼气实验室产量为0.799和0.803 m3/kg VS,沼气中甲烷浓度分别为52.84 vol%和53.17 vol%,4个示范小区厌氧生物降解率分别为82.52%、73.76%5、9.53%及64.41%;消化过程中,pH值的调节方式对沼气的产量及厌氧最终生物降解率无显著影响,对沼气的产气时间有影响。一次大量投料可缩短pH值调节时间,提高产气效率;沈阳市示范小区城市生物有机垃圾产气量(G)关于TS(T)、VS(V)的一元线性回归关系为:G=2.33+0.29T和G=0.89+0.65V,相关系数分别为0.980 3和0.907 5。[结论]该研究为生物有机垃圾厌氧消化制取甲烷的进一步研究提供了依据。     

Ex situ NMR in highly homogeneous fields: 1H spectroscopy

Portable single-sided nuclear magnetic resonance (NMR) magnets used for nondestructive studies of large samples are believed to generate inherently inhomogeneous magnetic fields. We demonstrated experimentally that the field of an open magnet can be shimmed to high homogeneity in a large volume external to the sensor. This technique allowed us to measure localized high-resolution proton spectra outside a portable open magnet with a spectral resolution of 0.25 part per million. The generation of these experimental conditions also simplifies the implementation of such powerful methodologies as multidimensional NMR spectroscopy and imaging.     

Chlamydiaceae in cattle: commensals, trigger organisms, or pathogens?

Epidemiological data indicate that infection of cattle with chlamydiae such as Chlamydophila (C.) pecorum, C. abortus, C. psittaci and Chlamydia suis, is ubiquitous with mixed infections occurring frequently. The apparent lack of association between infection and clinical disease has resulted in debate as to the pathogenic significance of these organisms, and their tendency to sub-clinical and/or persistent infection presents a challenge to the study of their potential effects. However, recent evidence indicates that chlamydial infections have a substantial and quantifiable impact on livestock productivity with chronic, recurrent infections associated with pulmonary disease in calves and with infertility and sub-clinical mastitis in dairy cows. Data also suggest these infections manifest clinically when they coincide with a number of epidemiological risk factors. Future research should: (1) use relevant animal models to clarify the pathogenesis of bovine chlamydioses; (2) quantify the impact of chlamydial infection at a herd level and identify strategies for its control, including sub-unit vaccine development; and (3) evaluate the zoonotic risk of bovine chlamydial infections which will require the development of species-specific serodiagnostics.     

Effects of boric acid on various microbes,plants, and soil invertebrates

Purpose  

Terrestrial ecotoxicology includes the investigation of the impact of chemicals on soils and soil-inhabiting organisms, whereby ecotoxicological effects are mainly assessed using single-species laboratory tests. As part of laboratory testing, reference substances, with known toxicity, are regularly used to confirm the sensitivity of the cultivated test organisms over time. Furthermore, reference substances are also applied in ring test evaluations for the validation of new test methods. The present work evaluates boric acid for its suitability as a potential reference substance for tests with higher plants and soil organisms (e.g., invertebrates and microbial communities).     

Determining chondritic impactor size from the marine osmium isotope record

Decreases in the seawater 187Os/188Os ratio caused by the impact of a chondritic meteorite are indicative of projectile size, if the soluble fraction of osmium carried by the impacting body is known. Resulting diameter estimates of the Late Eocene and Cretaceous/Paleogene projectiles are within 50% of independent estimates derived from iridium data, assuming total vaporization and dissolution of osmium in seawater. The variations of 187Os/188Os and Os/Ir across the Late Eocene impact-event horizon support the main assumptions required to estimate the projectile diameter. Chondritic impacts as small as 2 kilometers in diameter should produce observable excursions in the marine osmium isotope record, suggesting that previously unrecognized impact events can be identified by this method.