Mechanisms underlying the responses of microbial carbon and nitrogen use efficiencies to nitrogen addition are mediated by topography in a subtropical forest.

Microbial carbon use efficiency (CUE) and nitrogen use efficiency (NUE) are key parameters determining the fate of C and N in soils. Atmospheric N deposition has been found to heavily impact multiple soil C and N transformations, but we lack understanding of the responses of CUE and NUE to N deposition, and it remains uncertain whether responses may be mediated by topography. Here, a N addition experiment with three treatment levels (0, 50 and 100 kg N ha-1 yr-1) was conducted in the valley and on the slope of a subtropical karst forest. Nitrogen addition increased microbial CUE and NUE at both topographic positions, but the underlying mechanisms differed. In the valley, the increase in CUE was associated with an increase in soil fungal richness:biomass and lower litter C:N, whereas on the slope, the response was linked with a reduced ratio of dissolved soil organic C (DOC) to available phosphorus (AVP) which reduced respiration, and increased root N:P stoichiometry. In the valley, the increase in NUE was explained by stimulated microbial N growth relative to gross N mineralization, which was associated with increased ratios of soil total dissolved N:AVP and fungal richness:biomass. In contrast, on the slope, the increase in NUE was attributed to reduced gross N mineralization, linked to increased DOC:AVP. Overall, our results highlight how topography-driven soil substrate availability and microbial properties can regulate microbial CUE and NUE.

Polysaccharide of Atractylodes macrocephala Koidz(PAMK) protects against DEHP-induced apoptosis in grass carp hepatocytes.

Di(2-ethylhexyl) phthalate (DEHP) is a new environmental pollutant, which is widely used in plastic additives. DEHP and its metabolites pollute surface water and threaten the survival of fish. In order to investigate the mechanism of DEHP-induced apoptosis on grass carp hepatocytes, we treated grass carp hepatocytes with DEHP, and selected Atractylodes macrocephala Koidz (PAMK) to study its inhibitory effect on DEHP. The results showed that after DEHP exposure, apoptosis related proteins expression were increased significantly, leading to hepatocytes apoptosis. Moreover, AO/EB staining and Hoechst staining also showed that the number of apoptotic cells increased after DEHP exposure. It should be noted that PAMK simultaneous treatment could alleviate apoptosis induced by DEHP. The innovation of this study is that the application of Chinese herbal medicine (PAMK) to antagonize the damage of DEHP in fish was investigated for the first time. This study indicated that traditional Chinese medicine can also be used in fish production to reduce the accumulation of food-derived drugs.

Variation in Volatile Compounds of Raw Pu-Erh Tea upon Steeping Process by Gas Chromatography-Ion Mobility Spectrometry and Characterization of the Aroma-Active Compounds in Tea Infusion Using Gas Chromatography-Olfactometry-Mass Spectrometry.

Steeping process is an important factor for aroma release of tea, which has rarely been investigated for the aroma changes of raw Pu-erh tea (RAPT). In addition, the comprehensive aroma characteristics identification of RAPT infusion is necessary. In this study, GC-IMS coupled with principal component analysis (PCA) was used to clarify the difference of volatile profiles during the steeping process of RAPT. Furthermore, the volatiles contained in the RAPT infusion were extracted by three pretreatment methods (HS-SPME, SBSE, and SAFE) and identified using GC-O-MS. According to the odor activity value, 28 of 66 compounds were categorized as aroma-active compounds. Aroma recombination and omission experiments showed that "fatty", "green", "fruity", and "floral" are considered to be the main aroma attributes of RAPT infusion with a strong relationship with 1-octen-3-one, 1-octen-3-ol, (E)-2-octenal, ß-ionone, linalool, etc. This study will contribute a better understanding of the mechanism of the RAPT steeping process and volatile generation.

Elucidation of aroma compounds in passion fruit (Passiflora alata Ait) using a molecular sensory approach.

In this experiment, Guangxi passion fruit was used as the raw material for natural aroma extraction using the spinning cone column (Spinning Cone Column, SCC) technique. In combination with the semi-quantitative method, the aroma characteristics of the raw pulp (raw whole-fruit puree, PU) before SCC processing, residue (Residue, RS) and extract (Extract, EX) after SCC processing, and passion fruit juice (Juice, JU) were evaluated for their aroma characteristics using headspace gas chromatography-mass spectrometry (HS-SPME-GC-MS), gas chromatography-ion mobility spectrometry (GC-IMS), electronic nose, and sensory evaluation. As a result, a total of 110 aroma substances were detected in four samples, and 33, 38, 73, and 28 aroma components were detected from PU, RS, EX, and JU, respectively. There are 50 compounds in EX with concentrations greater than 10 µg/kg, and 19 of them had OAV values greater than 1, including ß-Ionone and linalool, which contributed significantly to the aroma. The aroma profiles and characteristics were further analyzed for JU and EX using the e-nose sensor, and it was found that both showed similar aroma profiles. The sensory evaluation results were also in general agreement with the results obtained from the electronic nose, with EX having mainly "floral", "fruity," and "sweet" aromas. The results demonstrated that the spinning cone column technique can increase the fresh and natural fruity aroma of passion fruit in the extract, which has the effect of enriching the aroma and improving the aftertaste. This study will make a foundation for passion fruit SCC extract application in drinks. PRACTICAL APPLICATIONS: Compared with traditional extraction technology, spinning cone column technology has the advantages of high mass transfer efficiency, short extraction time, a wide range of temperature control, and the most complete extracted flavor substances, which greatly reduces the damage degree of heat-sensitive flavor substances and condense aroma. It is widely used in beverages, wine, dairy products, fruit and vegetable, spice essential oil, and other industries. Passion fruit flavor prepared by SCC technology has the advantages of high purity and high concentration, which can be used in solid drinks, baked food, convenience food, tobacco, perfume, and other products. Besides, GC-IMS is an efficient and rapid new analytical technique, which has been widely used in the flavor analysis of volatile organic compounds in food and traditional Chinese medicine samples.

Coexistence of multiple leaf nutrient resorption strategies in a single ecosystem.

Leaf resorption is critical for considerations of how plants use and recycle nutrients, but fundamental unknowns remain regarding the controls over plant nutrient resorption. Empirical studies suggest at least three basic types of resorption control, including (i) stoichiometric control, (ii) nutrient limitation control, and (iii) nutrient concentration control strategies. However, which strategies are adopted in given conditions and whether multiple strategies coexist in an ecosystem are still open questions. To address these unknowns, leaf nitrogen (N) and phosphorus (P) resorption efficiency (NRE and PRE) and proficiency were measured for seven woody species at a nutrient-rich but potentially N-limited secondary forest and a nutrient-poor and potentially P-limited secondary forest. NRE was higher in the N-limited forest while PRE was higher in the P-limited forest, suggesting that plants responded to nutrient limitation with preferential resorption of the more limiting nutrient. NRE:PRE was positively related to leaf N:P ratios within each forest, demonstrating a role for stoichiometric control. Nutrient concentration controls were also found, with higher nutrient resorption proficiency in the nutrient-poor forest than in the nutrient-rich forest. The controls of stoichiometry and nutrient concentration were community-wide, but the nutrient limitation control was species-specific. Our results highlight the coexistence of multiple nutrient resorption strategies in a single ecosystem, and suggest these strategies are scale-dependent.

Substrate stoichiometry determines nitrogen fixation throughout succession in southern Chinese forests.

The traditional view holds that biological nitrogen (N) fixation often peaks in early- or mid-successional ecosystems and declines throughout succession based on the hypothesis that soil N richness and/or phosphorus (P) depletion become disadvantageous to N fixers. This view, however, fails to support the observation that N fixers can remain active in many old-growth forests despite the presence of N-rich and/or P-limiting soils. Here, we found unexpected increases in N fixation rates in the soil, forest floor, and moss throughout three successional forests and along six age-gradient forests in southern China. We further found that the variation in N fixation was controlled by substrate carbon(C) : N and C : (N : P) stoichiometry rather than by substrate N or P. Our findings highlight the utility of ecological stoichiometry in illuminating the mechanisms that couple forest succession and N cycling.

Impact of land use/land cover change on the topsoil selenium concentration and its potential bioavailability in a karst area of southwest China.

Selenium (Se) is an essential micronutrient for human health, and its abundance and potential bioavailability in the soil are of increasing concern worldwide. To date, how total soil Se and its bioavailability would respond to human disturbance or future environmental change is not yet clear, and associated controlling factors remain incompletely understood. Here, we collected soil samples (0-15 cm) from different land use/land cover types, including active cropland, grassland, shrubland, and secondary forest, in a Se-enriched area of Guangxi, southwest China. Total Se concentration and its potential bioavailability, as estimated by phosphate extractability, were investigated. Total soil Se concentration (Setotal) for all samples ranged from 220 to 1820 µg kg-1, with an arithmetic average value of 676 ± 24 µg kg-1 (Mean ± SE, the same below). The concentration of phosphate extractable Se (Sephosphate) varied between 1 and 257 µg kg-1, with an arithmetic mean value of 79 ± 5 µg kg-1, accounting for on average 13 ± 1% of the Setotal. Among the four land use/land cover types, Setotal and Sephosphate were generally more enriched in the secondary forest than those in the grassland and cropland. The content of soil organic carbon (SOC) was the overriding edaphic factor controlling the abundance and potential bioavailability of Se in topsoils. In addition, climatic variables such as mean annual precipitation and mean annual temperature were also key factors affecting the abundance and potential bioavailability of soil Se. Our results suggest that changes in land use/land cover types may deeply influence Se biogeochemistry likely via alterations in soil properties, particularly SOC content.

Resource limitation of soil microbes in karst ecosystems.

Knowledge about resource limitation to soil microbes is crucial for understanding ecosystem functions and processes, and for predicting ecosystem responses to global changes as well. Karst ecosystems are widespread in the world, and play a key role in regulating the global climate, however, the patterns of and mechanisms underlying microbial resource limitation in karst ecosystems remain poorly known. Here we investigated the microbial resource limitation in a karst region, by selecting four main land-use types, i.e. cropland, grassland, shrubland and secondary forest, in areas underlain by two lithology types, i.e. dolomite and limestone, in southwest China. Ecoenzymatic stoichiometry was used as an indicator of microbial resource limitation. Overall, soil microbes in karst ecosystems were more limited by carbon and phosphorus, rather than by nitrogen. Further analyses revealed that the patterns of carbon and phosphorus limitation were different among land-use or lithology types. Microbial carbon limitation was greatest in cropland and forest but lowest in grassland, and was greater under dolomite than under limestone. Microbial phosphorus limitation decreased from secondary forest to cropland under dolomite areas, but showed no difference among ecosystem types under limestone areas, indicating that lithology controls the pattern of microbial phosphorus limitation along the post-agriculture succession. Our study describes a general pattern of microbial resource limitation in karst ecosystems, and we suggest that lithology may provide a new mechanism for explaining the variations of microbial resource limitation along the post-agriculture succession in different regions.

Differences in the bioaccumulation of selenium by two earthworm species (Pheretima guillemi and Eisenia fetida).

Information on the bioaccumulation of selenium (Se) in soil invertebrates (e.g. earthworms) is rather scarce. In the present study, bioaccumulation of Se in two eco-physiologically different earthworms, namely anecic Pheretima guillemi and epigeic Eisenia fetida, was determined after 28 days exposure to a successive doses of Se-spiked soil, specifically 0.5, 5, 50, and 200 µg Se g-1 soil. The results showed that Se concentration in earthworms elevated with increasing exposure levels, and maximums were up to 54.6 and 83.0 µg g-1 dry weight in Pheretima guillemi and Eisenia fetida, respectively, after 4 weeks exposure to 200 µg Se g-1 soil. Exposure to Se caused significant inhibition on earthworm growth, with the fresh weight loss ranging from 8.9% to 80.5%. Bioaccumulation factors (BAFs), empirically-derived and non-steady state, ranged from 0.12 to 4.17 and generally declined at higher exposure levels. Moreover, BAFs of Pheretima guillemi were higher than those of Eisenia fetida in low-dose Se-spiked soils, but the opposite was true in high-dose soils, indicating there is a species-specific response to exposure of Se between different earthworms. Further research is thus needed to reveal the accumulation pattern of Se in a wider range of earthworm species other than Eisenia fetida, which allows a better risk assessment of excessive Se to soil invertebrates and higher order organisms.

Therapeutic effect of ulinastatin on pulmonary fibrosis via downregulation of TGF­ß1, TNF­α and NF­κB.

Pulmonary fibrosis is a chronic, progressive, lethal lung disease characterized by alveolar cell necrosis and dysplasia of interstitial fibrotic tissue, resulting in loss of lung function and eventual respiratory failure. Previously, glucocorticoid drugs were used to treat this lung disorder. However, positive responses were recorded in less than half of treated patients and the cytotoxicity caused by high dosage treatment is still a concern. The present study investigated whether ulinastatin, a typical urinary trypsin inhibitor that mitigates numerous inflammatory responses, could be a treatment option for lung fibrosis. The results demonstrated that ulinastatin had the ability to ameliorate interstitial fibrosis and alveolar exudates and to protect against lung diseases induced by smoke, irradiation or silica particles. The mechanism of ulinastatin resulted in the downregulation of inflammatory cascades: Transforming growth factor­ß1, tumor necrosis factor­α and nuclear factor­κB, as demonstrated by western blotting and ELISA. Ulinastatin treatment with a high dose (100,000 U/kg body weight/day) resulted in an attenuated inflammatory response, and inhibited fibrosis formation in lungs, suggesting that ulinastatin may become a part of a clinical therapeutic strategy.

[The Interaction of Oil Microcapsule Wall Materials between Whey Protein and Acacia].

The interaction between whey protein and acacia which were used as wall material was studied on the formation of the oils microcapsules by the FTIR Spectroscopy and Computer Aided Analysis. The results indicated that whey protein changed obviously in amide A and amide I by high pressured homogenization and spray-drying. The amide A moved from 3 406.5 cm(-1) to 3 425.4 cm(-1) which was possibly due to covalent cross-linking between whey protein and acacia. Furthermore the amide I moved from 1 648.6 cm(-1) to 1 654.7 cm(-1) for intramolecular hydrogen bonding of protein had been weaken. After Gaussian fitting on amide I , it was found that the content of secondary structure of α-helix content and ß-folding in whey protein reduced from 19.55% to 17.50% and from 30.59% to 25.63%, respectively. This suggests that protein intramolecular hydrogen bonding force was abated, resulting in abating the rigid structure of the protein molecules and enhancing of the toughness structure. The protein molecules showed some flexibility. The result of SDS-PAGE electrophoresis showed that whey protein--gum Arabic complexes produced covalent products in larger molecular weight. During the spray-drying process, covalent cross-linking produced between whey protein and gum Arabic which improved emulsifying activity of the complex whey protein and gum Arabic produced covalent cross-linking and improved the complex emulsifying activity. Observing the surface structure of the fish oil microcapsule by SEM, the compound of whey protein and acacia as wall material was proved better toughness, less micropore, and more compact structure.

Molecular cloning, expression profiles and characterization of a novel translationally controlled tumor protein in rubber tree (Hevea brasiliensis).

The translationally controlled tumor protein (TCTP) is a multi-functioning protein that carries out vital roles in various life processes. In this study, a new TCTP gene, designated as HbTCTP1, was isolated in Hevea brasiliensis. The full-length complementary DNA (cDNA) of HbTCTP1 contained a maximum open reading frame (ORF) of 507base pair (bp) encoding 168 amino acids. The sequence comparison showed that the deduced HbTCTP1 indicated high identities to plant TCTP proteins, and clustered in the dicot cluster of plant TCTPs. Although HbTCTP1 and human TCTP proteins did not parallel in overall sequence similarity, they indicated highly similar 3D structures with a nearly identical spatial organization of α-helices, ß-sheets, and coil regions. Real time reverse-transcription PCR (RT-PCR) analyses showed that HbTCTP1 was expressed throughout different tissues and developmental stages of leaves. Besides being related to tapping panel dryness (TPD), the HbTCTP1 transcripts were regulated by various treatments, including drought, low temperature, high salt, ethrel (ET), wounding, H2O2, and methyl jasmonate (Me-JA) treatments. The recombinant HbTCTP1 fusion protein was shown to protect supercoiled plasmid DNA from damages induced by metal-catalyzed generation of reactive oxygen species. The (45)Ca(2+)-overlay assay showed that HbTCTP1 was a calcium-binding protein. Our results are greatly helpful in understanding the molecular characterization and expression profiles of HbTCTP1, and lay the foundation for further analyzing the function of HbTCTP1 in rubber tree.

Identification of Yin Yang 1-interacting partners at -1026C/A in the human iNOS promoter.

Previously we demonstrated the association between human iNOS -1026C/A variant and susceptibility to hypertension, and found that -1026C/A altered the Yin Yang 1 (YY1)-binding pattern. In the current study, we verified that -1026C/A was located in a vital regulatory region of the iNOS promoter, wherein existed a DNA-binding complex composed of YY1, nuclear factor I (NFI) and activator protein-1 (AP-1). We also observed that YY1 bound dominantly to -1026C, and NFI bound dominantly to -1026A. Furthermore, the repressive effect of YY1 was more evident than NFI on the iNOS promoter activity, resulting in a more marked reduction of iNOS expression via YY1/AP-1 than via NFI/AP-1 under the stimulation of cytomix. In conclusion, diverse binding affinities of YY1 and its interacting partners to iNOS -1026C/A resulted in differential promoter activity, and potent inhibition of iNOS expression by YY1/AP-1 complex with -1026C may contribute to an enhanced risk for hypertension.

Functional characterization of rice OsDof12.

DNA-binding with one finger (Dof) proteins are a large family of transcription factors involved in a variety of biological processes in plants. In rice, 30 different Dof genes have been identified through genome analysis. Here we report the functional characteristics of a rice Dof gene, OsDof12, which encodes a predicted Dof protein. The nuclear localization of OsDof12 was investigated by the transient expression assays of the OsDof12-GFP fusion protein in onion epidermal cells. Trans-activation assays in a yeast one-hybrid system indicated that OsDof12 had transcriptional activity. RNA expression analyses showed that the expression of OsDof12 was not tissue-specific in general and fluctuated at different development stages in rice. In addition, OsDof12 was strongly inhibited by dark treatments. The transgenic lines overexpressing OsDof12 showed early flowering under long-day (LD) conditions, whereas OsDof12 overexpression had no effect on flowering time under short-day (SD) conditions. In transgenic lines overexpressing OsDof12, the transcription levels of Hd3a and OsMADS14 were up-regulated under LD conditions but not SD conditions, whereas the expression of Hd1, OsMADS51, Ehd1 and OsGI did not change under LD and SD conditions. These results suggested that OsDof12 might regulate flowering by controlling the expression of Hd3a and OsMADS14.

[A nimodipine interventional study of patients with mild cognitive impairment].

OBJECTIVE: To observe the effect of nimodipine on the cognition status and the changes of metabolites in brain tissue in the patients with mild cognitive impairment (MCI) in order to evaluate the significance of intervening MCI with medication. METHODS: 31 patients with MCI were selected 16 cases were in a treatment group taking nimodipine for 3 months besides taking basic internal medication and 15 cases in a control group taking only basic internal medication. Before and after treatment, multiple cognition tests were carried out in both groups and magnetic resonance spectroscopy (MRS) in Hippocampus region was carried out in 5 patients of the treatment group. RESULTS: Verbal instant recall scores, symbol digit modalities test (SDMT) scores and mini-mental state examination (MMSE) total scores in the treatment group were improved significantly after treatment as compared with those in the control group (P < 0.05). CONCLUSION: Nimodipine can improve memory ability as well as attention ability of the patients with MCI to a certain extent and make the general cognition function improved.

A pilot study of functional magnetic resonance imaging of the brain during manual and electroacupuncture stimulation of acupuncture point (LI-4 Hegu) in normal subjects reveals differential brain activation between methods.

OBJECTIVES: To characterize the brain activation patterns evoked by manual and electroacupuncture on normal human subjects. DESIGN: We used functional magnetic resonance imaging (fMRI) to investigate the brain regions involved in electroacupuncture and manual acupuncture needle stimulation. A block design was adopted for the study. Each functional run consists of 5 minutes, starting with 1-minute baseline and two 1-minute stimulation, the interval between the two stimuli was 1 minute. Four functional runs were performed on each subject, two runs for electroacupuncture and two runs for manual acupuncture. The order of the two modalities was randomized among subjects. During the experiment, acupuncture needle manipulation was performed at Large Intestine 4 (LI4, Hegu) on the left hand. For each subject, before scanning started, the needle was inserted perpendicular to the skin surface to a depth of approximately 1.0 cm. Electroacupuncture stimulation was delivered using a continuous rectangular wave form (pulse width 30 ms) at a frequency of 3 Hz. For manual acupuncture, the needle was rotated manually clockwise and counterclockwise at a rate of about 180 times per minute (3 Hz). SUBJECTS: Eleven right-handed, normal, healthy volunteer adults, 6 male and 5 female, ages 21-64 participated in the experiment. RESULTS: Results showed that electroacupuncture mainly produced fMRI signal increases in precentral gyrus, postcentral gyrus/inferior parietal lobule, and putamen/insula; in contrast, manual needle manipulation produced prominent decreases of fMRI signals in posterior cingulate, superior temporal gyrus, putamen/insula. CONCLUSION: These results indicate that different brain networks are involved during manual and electroacupuncture stimulation. It suggests that different brain mechanisms may be recruited during manual and electroacupuncture.