A semi-empirical model of methane emission from flooded rice paddy soils

Reliable regional or global estimates of methane emissions from flooded rice paddy soils depend on an examination of methodologies by which the current high variability in the estimates might be reduced. One potential way to do this is the development of predictive models. With an understanding of the processes of methane production, oxidation and emission, a semi-empirical model, focused on the contributions of rice plants to the processes and also the influence of environmental factors, was developed to predict methane emission from flooded rice fields. A simplified version of the model was also derived to predict methane emission in a more practical manner. In this study, it was hypothesized that methanogenic substrates are primarily derived from rice plants and added organic matter. Rates of methane production in flooded rice soils are determined by the availability of methanogenic substrates and the influence of environmental factors. Rice growth and development control the fraction of methane emitted. The amount of methane transported from the soil to the atmosphere is determined by the rates of production and the emitted fraction. Model validation against observations from single rice growing seasons in Texas, USA demonstrated that the seasonal variation of methane emission is regulated by rice growth and development. A further validation of the model against measurements from irrigated rice paddy soils in various regions of the world, including Italy, China, Indonesia, Philippines and the United States, suggests that methane emission can be predicted from rice net productivity, cultivar character, soil texture and temperature, and organic matter amendments.     

扎龙芦苇湿地生长季的甲烷排放通量

为研究高寒地区天然淡水芦苇湿地的甲烷排放特征,采用静态箱-气相色谱法,测定了扎龙不同水位芦苇湿地生长季的甲烷排放通量.结果表明:观测期内,扎龙芦苇湿地甲烷排放通量平均为7.67 mg·m^-2·h^-1（-21.18～46.15 mg·m^-2·h^-1）,其中深水区(平均水深100 cm)和浅水区(平均水深25 cm)的平均甲烷排放通量分别为5.81和9.52 mg·m^-2·h^-1,排放峰值分别出现在8月和7月,最低值均出现在10月.深水区夏季(6-7月)的甲烷排放通量显著低于浅水区,而春(5月)、秋(8-10月)季节显著高于浅水区.生长季甲烷排放通量的变化为夏季>秋季>春季;昼夜排放量为12:00和14:00最高,0:00最低.温度和水位是高寒地区淡水芦苇湿地甲烷排放通量变化的主要影响因子.     

Atnoa1 mutant Arabidopsis plants induce compensation mechanisms to reduce the negative effects of the mutation

Alterations in temperature adaptation processes and changes in the content of stress-related compounds, polyamines and salicylic acid were evaluated in Atnoa1 (NO-associated 1) Arabidopsis mutant. The F_v/F_m chlorophyll-a fluorescence induction parameter and the actual quantum yield were significantly lower in the Atnoa1 mutant than in the wild-type. In the wild-type Col-0, the fastest increase in the non-photochemical quenching (NPQ) occurred in plants pre-treated at low temperature (4 °C), while the slowest was in those adapted to 30 °C. The NPQ showed not only a substantially increased level in the light-adapted state, but also more rapid light induction after the dark-adapted state in the Atnoa1 mutant than in the wild-type. The results of freezing tests indicated that both the wild-type and the mutant had better freezing tolerance after cold hardening, since no significant differences were found between the genotypes. The level of putrescine increased substantially, while that of spermine decreased by the end of the cold-hardening (4 °C, 4 d) period. The quantity of spermidine in Atnoa1 was significantly higher than in Col-0, at both control and cold-hardening temperatures. A similar trend was observed for spermine, but only under control conditions. The mutant plants showed substantially higher salicylic acid (SA) contents for both the free and bound forms. This difference was significant not only in the control, but also in the cold-hardened plants. These results suggest that there is a compensation mechanism in Atnoa1 mutant Arabidopsis plants to reduce the negative effects of the mutation. These adaptation processes include the stimulation of photoprotection and alterations in the SA and polyamine compositions.     

Photochemical processes, carbon assimilation and RNA accumulation of sucrose transporter genes in tomato arbuscular mycorrhiza

Arbuscular mycorrhizal fungi enhance CO₂ assimilation of their hosts which ensure the demand for carbohydrates of these obligate biotrophic microorganisms. Photosynthetic parameters were measured in tomato colonised or not by the arbuscular mycorrhizal fungus Glomus mosseae. In addition, carbohydrate contents and mRNA accumulation of three sucrose transporter genes were analysed. Mycorrhizal plants showed increased opening of stomata and assimilated significant more CO₂. A higher proportion of the absorbed light was used for photochemical processes, while non-photochemical quenching and the content of photoprotective pigments were lower. Analysis of sugar contents showed no significant differences in leaves but enhanced levels of sucrose and fructose in roots, while glucose amounts stayed constant. The three sucrose transporter encoding genes of tomato SlSUT1, SlSUT2 and SlSUT4 were up-regulated providing transport capacities to transfer sucrose into the roots. It is proposed that a significant proportion of sugars is used by the mycorrhizal fungus, because only amounts of fructose were increased, while levels of glucose, which is mainly transferred towards the fungus, were nearly constant.     

Similarity between γ-Casein and a Product of β-Casein Hydrolysis by Milk Protease

A γ-casein-like fraction (FIV) was isolated from the β-casein A hydrolyzate by milk protease and compared with γ-casein. The mobility in polyacrylamide gel electrophoresis, sedimentation coefficient, molecular weight, amino acid composition and terminal amino acids of FIV were almost coincided with those of γ-casein. It is suggested that γ-casein is possibly a product of β-casein hydrolysis by milk protease.     

Responses of epidermal cell turgor pressure and photosynthetic activity of leaves of the atmospheric epiphyte Tillandsia usneoides (Bromeliaceae) after exposure to high humidity

It has been well-established that many epiphytic bromeliads of the atmospheric-type morphology, i.e., with leaf surfaces completely covered by large, overlapping, multicellular trichomes, are capable of absorbing water vapor from the atmosphere when air humidity increases. It is much less clear, however, whether this absorption of water vapor can hydrate the living cells of the leaves and, as a consequence, enhance physiological processes in such cells. The goal of this research was to determine if the absorption of atmospheric water vapor by the atmospheric epiphyte Tillandsia usneoides results in an increase in turgor pressure in leaf epidermal cells that subtend the large trichomes, and, by using chlorophyll fluorescence techniques, to determine if the absorption of atmospheric water vapor by leaves of this epiphyte results in increased photosynthetic activity. Results of measurements on living cells of attached leaves of this epiphytic bromeliad, using a pressure probe and of whole-shoot fluorescence imaging analyses clearly illustrated that the turgor pressure of leaf epidermal cells did not increase, and the photosynthetic activity of leaves did not increase, following exposure of the leaves to high humidity air. These results experimentally demonstrate, for the first time, that the absorption of water vapor following increases in atmospheric humidity in atmospheric epiphytic bromeliads is mostly likely a physical phenomenon resulting from hydration of non-living leaf structures, e.g., trichomes, and has no physiological significance for the plant's living tissues.     

Spontaneous trait transference from dogs to owners

Abstract

This work found that participants attributed traits associated with breeds of dogs to their owners (indicating that a person may be perceived as more nervous if believed to own a Chihuahua, more heroic if believed to own a Collie, more aggressive if believed to own a Doberman, etc.). The findings further suggest that some people have folk theories that owners select breeds of dogs that resemble them dispositionally. When participants were unable to use this folk theory (when it was clear that the target people were not the dogs' owners and just randomly happened to share the same environment) those participants who owned dogs themselves still transferred traits; however those who did not own dogs themselves did not do so. These findings provide evidence of a novel associative effect in person impression and are discussed in terms of simple associative versus inferential processes.     

Cariprazine (RGH-188), a potent D3/D2 dopamine receptor partial agonist, binds to dopamine D3 receptors in vivo and shows antipsychotic-like and procognitive effects in rodents

We investigated the in vivo effects of orally administered cariprazine (RGH-188; trans-N-{4-[2-[4-(2,3-dichlorophenyl)-piperazin-1-yl]-ethyl]-cyclohexyl}-N′,N′-dimethyl-urea), a D₃/D₂ dopamine receptor partial agonist with ∼10-fold preference for the D₃ receptor. Oral bioavailability of cariprazine at a dose of 1 mg/kg in rats was 52% with peak plasma concentrations of 91 ng/mL. Cariprazine 10 mg/kg had good blood-brain barrier penetration, with a brain/plasma AUC ratio of 7.6:1. In rats, cariprazine showed dose-dependent in vivo displacement of [³H](+)-PHNO, a dopamine D₃ receptor-preferring radiotracer, in the D₃ receptor-rich region of cerebellar lobules 9 and 10. Its potent inhibition of apomorphine-induced climbing in mice (ED₅₀ = 0.27 mg/kg) was sustained for 8 h. Cariprazine blocked amphetamine-induced hyperactivity (ED₅₀ = 0.12 mg/kg) and conditioned avoidance response (CAR) (ED₅₀ = 0.84 mg/kg) in rats, and inhibited the locomotor-stimulating effects of the noncompetitive NMDA antagonists MK-801 (ED₅₀ = 0.049 mg/kg) and phencyclidine (ED₅₀ = 0.09 mg/kg) in mice and rats, respectively. It reduced novelty-induced motor activity of mice (ED₅₀ = 0.11 mg/kg) and rats (ED₅₀ = 0.18 mg/kg) with a maximal effect of 70% in both species. Cariprazine produced no catalepsy in rats at up to 100-fold dose of its CAR inhibitory ED₅₀ value. Cariprazine 0.02-0.08 mg/kg significantly improved the learning performance of scopolamine-treated rats in a water-labyrinth learning paradigm. Though risperidone, olanzapine, and aripiprazole showed antipsychotic-like activity in many of these assays, they were less active against phencyclidine and more cataleptogenic than cariprazine, and had no significant effect in the learning task. The distinct in vivo profile of cariprazine may be due to its higher affinity and in vivo binding to D₃ receptors versus currently marketed typical and atypical antipsychotics.     

Human amniotic epithelial cells inhibit activation and pro-inflammatory cytokines production of naive CD4+ T cells from women with unexplained recurrent spontaneous abortion

Unexplained recurrent spontaneous abortion (URSA) has been assumed to be caused by a defect in maternal immunological tolerance to the fetus. Human amniotic epithelial cells (hAECs) have stem cell-like features and the ability to modulate the innate and adoptive immune responses. This study aimed to investigate whether hAECs have immunomodulatory effects on naive CD4+ T cells from URSA patients. hAECs were obtained from 15 healthy pregnant women and phenotypic profile of hAECs was determined by flow cytometry. Naive CD4+ T cells were isolated from 25 URSA patients using an immunomagnetic separation method. Naive T cells were stimulated with anti-CD3/anti-CD28 antibodies and co-cultured with different numbers of hAECs for 3 and 6 days. Immunomodulatory effect of hAECs on activation of stimulated T cell was assessed by flow cytometry and Enzyme-linked immunoasorbent assay (ELISA). The hAECs effect on pro-inflammatory cytokines production of activated T cells was also measured by ELISA. Our results indicated that hAECs significantly inhibited the activation of naive T cells in a dose-dependent manner (p?<?0.0001–0.05). They significantly reduced the production of transforming growth factor-beta1 (TGF-β1) of stimulated CD4+T cells (p?<?0.0001–0.05). Moreover, hAECs had potent immunomodulatory effects on the production of interferon-gamma (IFN-γ) and interleukin-17A (IL-17A) of activated T cells (p?<?0.0001–0.01). These findings suggest that hAECs may be a suitable cell source to modulate abnormal immune responses in women with URSA.