Change characteristics and influencing factors of grassland degradation in adjacent areas of the Qinghai-Tibet Plateau and suggestions for grassland restoration.

Natural grasslands are being progressively degraded around the world due to climate change and socioeconomic factors. Most of the drivers, processes, and consequences of grassland degradation are studied separately, and it is not yet clear whether the change characteristics and influence factors of adjacent areas of grassland are identical. We analyzed changes in grassland area and quality, and the influences of climate changes and socioeconomic factors from 1980-2018 in Maqu County, Xiahe County and Luqu County on the eastern Qinghai-Tibet Plateau (QTP). We found that areas with high and medium coverage grassland in Maqu County and Luqu County decreased continuously with time, while low coverage grassland areas increased in three counties. In Xiahe County, the medium coverage grassland area reduced with time (except for 2010), while the high and low coverage grassland areas increased. The actual net primary productivity of the three counties showed a downward trend. In Maqu County, the total grassland area had an extremely significant positive correlation with number of livestock going to market, commodity rate, gross domestic product (GDP), primary industry, tertiary industry, household density, and levels of junior middle school education and university education in the area. In Luqu County, the total grassland area high coverage grassland area were significantly negatively correlated with total number of livestock, secondary industry, levels of primary school education, and temperature. Ecological education was positively correlated with high coverage grassland, and negatively correlated with low coverage grassland in all three areas. The results of this study suggest that the best ways to restore the area and quality of grasslands in these areas would be to reduce the local cultivated land area and slow down the development of the primary and tertiary industries in Maqu County, and to control industry development and the total number of livestock in Luqu County. This study also suggests that improving education level and strengthening the level of ecological education are conducive to the restoration of grasslands.

The active synergetic microbiota with Aspergillus as the core dominates the metabolic network of ester synthesis in medium-high temperature Daqu.

The active ester-synthesis microorganisms in medium-high temperature Daqu (MHT-Daqu) largely impact the strong-flavor Baijiu quality, while their actual composition and metabolic mechanism remain unclear. Here, to explore how the active microbiota contributes to MHT-Daqu ester biosynthesis, metatranscriptomic and metaproteomic analyses coupled with experimental verification were performed. The results showed that the MHT-Daqu microbiota with the higher ester-forming ability exhibited a more active dynamic alteration from transcription to translation. The genera Aspergillus, Bacillus, Leuconostoc, and Pediococcus could transcribe and translate obviously more ester-forming enzymes. In the ester-synthesis metabolic network, the synergetic microbiota confirmed by interaction analysis, containing Eurotiales, Bacillales, and Saccharomycetales, played an essential role, in which the Eurotiales and its representative genus Aspergillus contributed the highest transcript and protein abundance in almost every metabolic process, respectively. The recombined fermentation verified that their corresponding genera could produce the ester and precursor profiles very close to that of the original MHT-Daqu active microbiota, while the microbiota without Aspergillus caused a polar separation. These results indicated that the synergetic microbiota with Aspergillus as the core dominated the metabolic network of ester synthesis in MHT-Daqu. Our study provides a detailed framework of the association between the active synergetic microbiota and ester synthesis in MHT-Daqu.

Integrating metabolomics and metatranscriptomics to explore the formation pathway of aroma-active volatile phenolics and metabolic profile during industrial radish paocai fermentation.

The aroma profile of industrial Sichuan paocai is formed and regulated by complex physiological and biochemical reactions and microbial metabolism, but little is known so far. In this study, we comprehensively analyzed the changes of metabolic profile and gene expression profile, mainly explored the formation pathways of two skeleton aroma-active compounds, 4-ethylphenol and 4-ethylguaiacol, and verified the pathways at multiple levels. The results showed that a total of 136 volatile metabolites and 560 non-volatile metabolites were identified in the whole fermentation process. The types and concentrations of metabolites in paocai were higher than those in brine, and gradually converged with fermentation. Differential analysis of metabolism and transcription levels were both enriched in three pathways: amino acid metabolism, phenylpropanoid metabolism and lipid metabolism. Among them, 4-ethylphenol and 4-ethylguaiacol, the products of the phenylpropanoid metabolism, were converted from p-coumaric acid and ferulic acid in plant cell walls, respectively. Under the action of decarboxylase produced by yeast (such as Debaryomyces Hansenii) and lactic acid bacteria (such as Lactobacillus versmoldensis), intermediate metabolites vinylphenols were produced, and the intermediate metabolites further produce the final products under the action of vinylphenol reductase. The key gene copy number, enzyme activity, and metabolite concentration in the pathways were detected to provide stronger evidence for the formation pathways. This study provided meaningful new insights for the development of aroma-producing enzymes and further guidance for the flavor improvement of industrial paocai.

Difference of microbial community and gene composition with saccharification function between Chinese nongxiangxing daqu and jiangxiangxing daqu.

BACKGROUND: The saccharification function of daqu is usually characterized by two indicators: saccharification power and liquefaction power. Daqu provides diverse microbial saccharifying enzymes for hydrolyzing carbohydrate in Baijiu fermenting grain. Obviously, the composition of microbial communities and enzymatic genes in different types of daqu cultured at varied temperatures is different. However, these differences in saccharification function are not fully understood. RESULTS: The findings suggested that the saccharification power and liquefaction power of jiangxiangxing daqu were lower than those of nongxiangxing daqu throughout the production process. We employed metagenomics to find evidence that a mode of multiple saccharifying enzymes involving amylase, cellulase and hemicellulase originating from various microbes exists in daqu. Moreover, a totality of 541 related differential genes were obtained, some of which, annotated to genera of Aspergillus, Lactobacillus and Weissella, were significantly enriched (P < 0.05) in nongxiangxing daqu, while others, annotated to thermophilic genera of Virgibacillus, Bacillus, Kroppenstedtia and Saccharopolyspora, showed a higher relative abundance in jiangxiangxing daqu (P < 0.05). CONCLUSION: Various microbial communities of daqu showed diverse saccharification capacity during cultivation of different parameters. These findings are helpful in comprehending the saccharification functional genes of daqu. © 2022 Society of Chemical Industry.

Temperature-dependent alcohol acyltransferase reactions as the main enzymatic way to produce short-chain (C4-C8) and medium-chain (C9-C13) esters over the whole Daqu-making process.

BACKGROUND: The ester-synthesis enzymes influenced by environmental factors during Daqu-making process largely determine the flavor of Chinese liquor, but the main ester-synthesis enzyme and its key influencer remain unclear. Here, the volatile ester profiles over the whole Daqu-making process, under different treatments, for at least 90 days, were carefully analyzed, and the potential ester-synthesis enzymes, as well as their dependently environmental factors, were explored. RESULTS: In the detected 46 volatile esters, only the short-chain (C4-C8) and medium-chain (C9-C13) ester content obviously changed, as the primary contributor discriminating different samples. Their trends were both consistent with that of the alcohols and the primary metabolism, which included alcohol acyltransferases (AATs) reaction with alcohols and acyl-CoAs as the substrates. Among the potential ester-synthesis enzymes, the typical AAT activity also exhibited the highest correlation with the short- and medium-chain esters (r > 0.78, P < 0.05). The Mantel test between environmental factors and ester production showed that temperature of Daqu was directly correlated with the short-chain esters (r = 0.58, P < 0.01) and AAT activity (r = 0.56, P < 0.01). Further, the short- and medium-chain ester content in Daqu under the treatment nearer to the reported optimal temperature of 40-50 °C of AATs reaction was overall higher than that of the other treatment Daqu. CONCLUSION: This study revealed that the temperature-dependent AATs reaction was the main enzymatic method producing the short- and medium-chain esters over the whole Daqu-making process. The results could contribute to the flavor improvement of Baijiu. © 2022 Society of Chemical Industry.

Prevalence of Helicobacter pylori Virulence Genes and Their Association with Chronic Gastritis in Beijing, China.

Helicobacter pylori is closely related to chronic gastritis. The aim of the study was to investigate the correlation between H. pylori virulence genes and chronic gastritis in order to determine the pathogenic role of H. pylori virulence genes in chronic gastritis. Gastric mucosal tissues were obtained from 142 patients with chronic gastritis at three Beijing hospitals. The presence of virulence genes was determined by polymerase chain reaction (PCR) from H. pylori DNA. Multilocus sequence typing (MLST) and a phylogenetic tree were performed to characterize the overall genetic diversity. 91 new sequence types were identified by MLST in this study, and all strains showed high genetic diversity. The H. pylori isolates were divided into three types: hspEAsia strains (61 strains), hpEurope strains (15 strains), and mixed strains (16 strains). Some virulence genes were found to be significantly different between strains. The highest positive rates were found for dupA in chronic atrophic gastritis (AG), iceA1 in chronic non-atrophic gastritis with erosions, and iceA2 in chronic non-atrophic gastritis. The presence of dupA was found to be inversely related to the risk of AG. The H. pylori strains display high genetic diversity. Some virulence genes were found to be significantly different between diseases. The detection of various virulence genes is critical for screening high-risk populations for precancerous lesions and for the early prevention and control of gastric cancer.

Development of nitrogen efficiency screening system in alfalfa (Medicago sativa L.) and analysis of alfalfa nitrogen efficiency types.

Screening high nitrogen (N) efficiency crops is crucial to utilize resources rationally and reduce N losses. In this research, the biomass, morphological and N-related parameters of 28 alfalfa (Medicago sativa L.) cultivars were assessed at seedling stage. Then, we selected representative materials to compare the changes in stem-leaf dry weight (SDW), total root length (RL) and plant N accumulation (PNA) during whole period. Lastly, we analyzed the expressions of NRT2 and AMT1 genes of alfalfa cultivars. The correlation coefficients between SDW, PDW, RL, RV, SNA, RNA, and PNA were all in the range of 0.522∼0.996. The coefficient of variations of SDW, PDW, RL, RV, SNA and PNA were all more than 20% under low and medium N levels. Though the comprehensive evaluation and cluster analysis, the comprehensive value of LW6010, Gannong NO.5, Longmu 806, Giant 2, Giant 601, Zhaodong, Crown were greater than 0.5 under low and medium N levels; the comprehensive value of Gannong NO.3, Gannong NO.4, Xinjiangdaye, Xinmu NO.1 were less than 0.5 under low N level, but were greater than 0.5 under medium N level. The comprehensive value of Gannong NO.7 Gannong NO.9, Longmu 801, Gongnong NO.3, Elite, Sadie 10, Giant 551 were greater than 0.5 under low N level, but were lesser than 0.5 under medium N level; and those of Longdong, Gannong NO.8, Gongnong NO.1, Reindee, Goldqueen, Weston, Tourists, Giant 6, Algonquin, Sadie 7 were lesser than 0.5 under low and medium N levels. Four N efficiency types of alfalfa cultivars were classified: (1) Very efficient; (2) Efficient; (3) Anti-efficient; and (4) Inefficient.The SDW, RL and PNA of LW6010 were higher than Longdong in each growth period. The expressions of NRT2 and AMT1 genes were highest for LW6010, and lowest for Longdong. So, N efficiency parameters assessed at seedling stage include: SDW, PDW, RL, RV, SNA and PNA. We developed new classification system of N efficiency types of alfalfa cultivars. It proved its effectiveness on 28 alfalfa in China.

Study on the Effect of Key Genes ME2 and adhE during Luzhou-Flavor Baijiu Brewing.

Luzhou-flavor baijiu (LFB) is brewed by the combined action of various microorganisms, and its flavor is affected by the microbial community and the genes they express, but which genes are the key ones during LFB brewing is less clear. Based on our previous studies the genes ME2 and adhE were identified as key genes, but which role they play was also unknown. In this study functional microorganisms were screened based on the key genes ME2 and adhE, and they were identified to be Rummeliibacillus suwonensis, Clostridium tyrobutyricum and Lactobacillus buchneri. Then simulated fermentation experiments were carried out with the functional microorganisms, and during the fermentation process expression of the key genes and the amounts of the main flavors were detected to analyze the role of the key genes. The results showed that the key gene ME2 was significantly positively correlated with the contents of the main acids, however the key gene adhE and the formation of the main esters in the LFB brewing process was a significant positive correlation. This study verified the two key genes ME2 and adhE complement each other in the LFB brewing process, playing an important role in promoting the formation of flavor substances, and are very beneficial to improve the quality of LFB.

Rapid detection of cagA-positive Helicobacter pylori based on duplex recombinase aided amplification combined with lateral flow dipstick assay.

Infection with cytotoxin-associated gene A (cagA)-positive Helicobacter pylori (H. pylori) is associated with severe gastrointestinal disease. A rapid, simple, and convenient detection method for cagA-positive H. pylori was an urgent need. We have developed and evaluated a duplex recombinase aided amplification combined with lateral flow dipstick (Duplex RAA-LFD) assay for detection of cagA-positive H. pylori strains. The Duplex RAA-LFD successfully detected DNA extracts in 25 min at 39°C, with visual detection limits of 1.2 × 102 CFU/mL and 10 pg, respectively. No positive amplification was observed in 6 non-H. pylori strains, indicating higher specificity. When testing 56 clinical isolates, the sensitivity and specificity of the Duplex RAA-LFD assay were 96% and 100%, respectively, with Duplex PCR serving as the reference method. Therefore, the Duplex RAA-LFD assay is a potential rapid and effective alternative to detect cagA-positive H. pylori strains in fresh gastric mucosal tissue.

Characterization of aroma and bacteria profiles of Sichuan industrial paocai by HS-SPME-GC-O-MS and 16S rRNA amplicon sequencing.

Sichuan industrial paocai and traditional home-made paocai have different aroma profiles due to different manufacturing techniques, but detailed information about the aroma profiles and aroma-producing microorganism of Sichuan industrial paocai remain largely elusive. For this reason, we established and validated an external standard method of headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with gas chromatography-olfactometry (GC-O) for identification and accurate quantitation of aroma-active compounds in Sichuan industrial paocai. This method was combined with 16S rRNA amplicon sequencing to comprehensively analyze the aroma and bacteria profiles of Sichuan industrial paocai. A total of 121 volatile compounds were identified, among which 36 odorants were identified as aroma-active compounds with aroma intensities (AIs) ranging from 0.67 to 5.00 by GC-O. The types of aroma-active compounds in Sichuan industrial paocai were variety-specific to some extent, but the aroma-active compounds shared by different varieties of Sichuan industrial paocai (i.e., skeleton aroma-active compounds) were phenylethyl alcohol, acetic acid, butanoic acid, 2-methylbutanoic acid, ethyl hexanoate, 4-ethylphenol and 4-ethylguaiacol. Moreover, 17 key aroma-active compounds of AI > 1 in radish paocai were quantitated by external standard method, and their odor activity values (OAVs) were calculated based on the odor thresholds. Further, 12 aroma-active compounds with OAV ≥ 1 in one of the radish paocai were selected to construct the recombination model, which revealed good agreement with the original sample. Furthermore, Lactobacillus, Pediococcus, Pseudomonas and Sphingomonas were the dominant bacteria in Sichuan industrial paocai. Correlation analysis between 16 dominant bacteria and 36 aroma-active compounds showed that Pediococcus, Arcobacter and Lactobacillus could be the core aroma-producing bacteria of Sichuan industrial paocai.

[Effects of Medicago sativa-Triticale wittmack intercropping system on rhizosphere soil nutrients and bacterial community in semi-arid region of NorthwestChina]. / 西北半干旱区紫花苜蓿-å°é»‘éº¦é—´ä½œå¯¹æ ¹é™ åœŸå£¤å »åˆ†å’Œç»†èŒç¾¤è½çš„å½±å“.

Semi-arid region of Northwest China is characterized by barren soil, with high pH and high carbonate content. Saline-alkali land is easily formed in this area, which inhibits soil microbial activity and results in soil nutrient loss. To improve soil health in this area, effects of intercropping alfalfa and triticale on rhizosphere soil nutrients and bacterial community structure were examined though a three-consecutive-year experiment. The results showed that soil organic matter (SOM) content of alfalfa rhizosphere in intercropping was significantly higher than that in monoculture, while pH and available potassium (AK) content were lower than that in monoculture. The concentrations of SOM, available nitrogen (AN), available phosphate (AP) and AK of triticale rhizosphere in intercropping were significantly higher than those in monoculture. The bacterial sequences, OTUs, richness, and diversity of alfalfa and triticale in rhizosphere soil were all higher than those in monoculture. At phylum level, Proteobacteria and Bacteroidetes were dominant, accounting for 31.1%-33.4% and 22.4%-32.2% of the total OTUs, respectively. The relative abundance of Bacteroidete was higher in intercropping than in monoculture. Actinomycetes in the monoculture were significantly higher. Acidobacteria in the intercropping triticale was significantly higher than that in monoculture triticale. Verrucomicrobia in intercropping alfalfa was significantly more abundant than that in monoculture of alfalfa. At genus level, Algoriphagus, Flavobacterium, Gp6, and Chryseolinea in monoculture were greater than those in intercropping, and Cellvibrio showed an opposite trend. Results of correlation analysis showed that the abundance of Proteobacteria and Bacteroidetes were negatively correlated with soil pH, while that of Bacteroidetes were positively correlated with SOM, TN and AN. However, the abundance of Chloroflexi, Planctomycetes, Acidobacteria, Verrucomicrobia, and Gemmatimonadetes was negatively correlated with SOM and AN. Overall, alfalfa-triticale intercropping is an effective strategy to improve soil health in semi-arid region of Northwest China.

Effect of root interaction on nodulation and nitrogen fixation ability of alfalfa in the simulated alfalfa/triticale intercropping in pots.

Cereal/legume intercropping is likely to achieve the optimal exploitation of soil and atmospheric nitrogen (N) sources to maintain high production and quality levels with low N inputs, as an attempt to eliminate underlying environmental effects. Nevertheless, the extent of the effect of cereal/legume intercropping on nodulation and N fixation of intercropped legumes in root interaction requires extensive verification. In the present study, root interaction of alfalfa/triticale intercropping was simulated in pots with the use of root separation types (pot with no barrier (A-T), pot with nylon mesh barrier (NA-T), pot with plastic barrier (PA-T), and alfalfa alone (SA)) in pots. Moreover, the experiment was measured at a range of N levels (N21, N210) and growing stages (branching, budding and initial flowering stages) in growth chamber. As alfalfa was growing, the total nodule number (TNN), effective nodule number (ENN) and nitrogenase activity (NA) of alfalfa with A-T and other cropping systems more noticeably differed from each other at higher N levels, whereas their diversification was reduced at lower N levels. As alfalfa was growing continuously, fresh nodule weight per plant (PNW) and single fresh nodule weight (SNW) with A-T and other cropping systems were amplified more significantly. The nodulation and N fixation ability under N21 were more significant than those under N210. Dry weight of plant per pot (TDW) and nitrogen accumulation of plant per pot (TNA) with A-T were obviously higher than those with other systems in the initial flowering stage, except for TNA under N21. The parameters regarding the nodulation and N fixation ability were significantly positively correlated on the whole. However, SNW and TNA were not significantly correlated, neither were SNW and TDW. According to the mentioned results, the closer root interaction, the better the nodulation form and N fixation ability of alfalfa will be, and the higher the biomass and N accumulation of all plants in pots will be. Interspecific facilitation in alfalfa/triticale intercropping system resulted in a greater yield and N accumulation; it also ultimately enhanced nodulation and N fixation ability, which can be applied in sustainable systems to avoid N loss to the environment and enhance N use efficiency.

Effects of endoplasmic reticulum stress on the expression of inflammatory cytokines in patients with ulcerative colitis.

AIM: To explore the changes of X-box binding protein 1 splicing (XBP1s) and inflammatory cytokine expression in patients with ulcerative colitis (UC) in response to endoplasmic reticulum stress (ERS). METHODS: Reverse transcription polymerase chain reaction and quantitative polymerase chain reaction were performed to detect the forms of XBP1s and the expression of interleukin (IL)-2, interferon (IFN)-γ, and IL-17α. Differences between patients with UC and normal subjects were then determined. RESULTS: Mononuclear cells of the peripheral blood of normal subjects and UC patients with were stimulated with no drugs (control), phytohemagglutinin (PHA), thapsigargin (TG), or both PHA and TG. XBP1s in patients with UC exhibited splicing, which was greater with co-stimulation than single stimulation. Co-stimulation increased the expression level of IL-2, IFN-γ, and IL-17α. CONCLUSION: The T lymphocytes of both normal subjects and patients with UC responded to ERS by activating the XBP1s-mediated signalling pathway, upregulating the expression of inflammatory cytokines, and increasing the occurrence of inflammation. The mononuclear cells in the peripheral blood of patients with UC were more sensitive to ERS than those in the peripheral blood of normal subjects.