Total Amount Of Organic Acids Research Articles

Morphological and Physiological Mechanism of Activating Insoluble Inorganic Phosphorus of Different Peanut (Arachis hypogaea L.) Varieties under Low Phosphorus

To reduce the application of phosphorus fertilizer and improve phosphorus efficiency in peanut (Arachis hypogaea L.) production, six peanut varieties with different phosphorus activation efficiencies were selected, and the root morphology, physiological indexes, and types and content of organic acids secreted were measured via a hydroponic experiment for 20 days. We analyzed the difference in calcium phosphate activation between peanut seedlings cultivated under low-phosphorus (LP, 0.01 mmol/L KH2PO4) and normal phosphorus (NP, 0.6 mmol/L KH2PO4) conditions and explored the physiological mechanisms of different peanut varieties on the activation efficiency of insoluble inorganic phosphorus. The results showed that under LP conditions, the root length, root surface area, root volume, root tip number, and root activity of the efficient P activation varieties were 18.31%, 17.50%, 15.23%, 20.00%, and 50.90% higher than those of the inefficient P activation varieties respectively. The reduction range of the nutrient solution pH of the high-efficiency varieties was 74.48% higher than that of the low-efficiency varieties under LP conditions. The total amount of organic acid secreted by the efficient P activation varieties increased by 236.07% on average under LP conditions compared with that under NP conditions. In comparison, the average increase in inefficient P activation varieties was only 16.36%. Under low P stress, the peanut varieties with high-efficiency P activation could increase the activation of insoluble inorganic P in the environment mainly by changing the root architecture and increasing the root-shoot ratio, root activity, and root proton and organic acid secretion.

Type and Amount of Dietary Fiber Influence the Hindgut Synthesis of Organic Acids from Fermentable Material of Both Total and Nondietary Origin in a Pig Model of the Adult Human

BackgroundOrganic acid synthesis by the hindgut microbiota is commonly believed to be mainly of fermentable material of dietary origin. ObjectiveThis study aimed to determine the hindgut organic acid synthesis from fermentable material of dietary (mainly fiber) or nondietary origin for different types and amounts of dietary fiber in growing pigs used as a model for adult humans. MethodSeven fiber-containing diets were formulated: 4 fiber types (cellulose, gum acacia, oligofructose, and pectin) at 6% of the diet and 3 (gum acacia, oligofructose, and pectin) at 3% as the sole fiber source. Ileal cannulated female pigs (n = 14; Landrace/Large white) were fed the fiber-containing diets (n = 6 pigs/diet) for 11 days (fiber phase) followed by 3 days on a fiber-free diet (fiber-free phase), using a replicated Youden square. Ileal digesta for each phase were collected and fermented in vitro with a pooled fecal microbial inoculum prepared from feces collected during the fiber phase to determine the organic acids synthesized from fermentable material of dietary (fiber phase) and nondietary (fiber-free phase) origins. ResultsThe total amount of each individual organic acid synthesized during in vitro hindgut fermentation differed (P ≤ 0.05) across the types and amounts of dietary fiber intake. For example, the amount of acetate was 3.6-fold higher (P ≤ 0.05) for pigs fed the 6% pectin-containing diet than those fed the 6% oligofructose-containing diet. The nondietary substrate contributed between 36% (hexanoate) and 70% (succinate) to the total hindgut organic acid synthesis. The adaptation to the different fiber-containing diets led to different amounts of some organic acids of nondietary origin. ConclusionsThe total amount of organic acids synthesized in the hindgut by the resident microbes is influenced by the type and amount of dietary fiber consumed. This study quantifies the interaction between both dietary and nondietary fermentable materials in hindgut fermentation.

Environmental factors drive microbial succession and huangjiu flavor formation during raw wheat qu fermentation

As the core raw material of huangjiu (Chinese rice wine) production and brewing, changes of physichemical factors during the fermentation process significantly affect the succession of the microbial community of raw wheat qu (RWQ), also playing important role in huangjiu quality. In this report we analyzed the community structure and driving force RWQ microorganisms with different processes (manual qu, MAQ; mechanical qu, MEQ), and evaluating the flavor of huangjiu. The production procedure was divided into three stages. Dominant microorganisms were Aspergillus, Alternaria, Epicoccus, Bacillus, Pantoea, Saccharopolyspora and Staphylococcus. In early stage, microbial community of MAQ was significantly correlated with temperature and water content, oxygen in middle stage, while no significant driving force in the last stage. Water content and oxygen affected MEQ community significantly in early stage, while in the final stage, fungal community was affected by both temperature and water content, and bacterial community was significantly correlated with oxygen. Glucoamylase activity reached its maximum at 50 °C, while the α-amylase activity decreased with the rise of temperature. The highest amylase activity was obtained with 19% initial water addition. Amylase activity showed positive correlation with the thickness of RWQ. The total amount of organic acids was higher in mechanical huangjiu at the end of pre-fermentation. Contents of n-hexanol, ethyl isovalerate, ethyl hexanoate and guaiacol in manual huangjiu were significantly higher than those in mechanical one, while the content of 4-vinylguaiacol was lower.

METABOLIC ACTIVITY OF LACTIC ACID BACTERIAL STRAINS AFTER THEIR INTRODUCTION INTO ALFALFA HAYLAGE

Objective. Study the metabolic activity of strains of lactic acid bacterial strains after their introduction into alfalfa haylage as a component of preservatives. Methods. Microbiological (determining the number of microorganisms, obtaining antibiotic-resistant mutants of bacterial strains), zootechnical (pH level, accumulation and ratio of organic acids in the fermentation process), statistical. Results. Lactobacillus plantarum KT-L18/1str, L. plantarum 32str strains introduced into the haylage substrate are stored in the feed in an active state for a long time and at day 30 of fermentation take a dominant position among native lactic acid bacteria, retaining 80 % of the acid-forming capacity and antagonistic activity against Staphylococcus aureus. The best results of the action of the studied lactic acid bacteria (LAB) after introduction into alfalfa haylage were obtained when the mass was dry-cured to a moisture content of 60–61 %, while the share of lactic acid in the total amount of organic acids formed in the experimental variants of the haylage ranged from 85.5 % to 89.3 % versus the control, where the share of lactic acid reached only 42 %. Increasing the degree of feed acidification in experimental variants at a given alfalfa moisture content ensured a decrease in the butyric acid content to 1.12–1.7 % versus 26.3 % in the control variant. Treatment of alfalfa haylage dry-cured to a moisture content of 38–39 % with strains of lactic acid bacteria did not affect the increase in the proportion of lactic acid. Conclusion. The use of probiotic L. plantarum KT-L18/1str and L. plantarum 32str made it possible to establish their competitiveness and metabolic activity in the process of alfalfa haylage preparation. The use of LAB probiotic strains for alfalfa haylage preparation improved fermentation processes, in particular, when dry matter content was at the level of 39–40 %.

Novel chromatographic purification of succinic acid from whey fermentation broth by anionic exchange resins.

Replacement of the petroleum-based refineries with the biorefinery is regarded as an essential step towards a "zero" waste (circular) economy. Biobased succinic acid (SA) is listed by the United States Department of Energy among the top ten chemicals with the potential to replace chemicals from petroleum synthesis with renewable sources. Purification of bio-based succinic acid from fermentation by-products such as alcohols, formic acid, acetic acid and lactic is a major drawback of fermentative SA production. This study addresses this issue through a novel chromatographic separation using three distinct anionic resins: Amberlite IRA958 Cl (strong base anion exchange resin), Amberlite HPR 900 OH (strong base anion exchange resin) and Amberlyst A21 (week base anion exchange resin). The influence of process variables such as flow rate (0.18 BV/h, 0.42 BV/h and 0.84 BV/h), eluent concentration (1%, 5% and 10% HCl) and temperature (20, 30 and 40°C) were investigated. The results indicated SA separation efficiency of 76.1%, 69.3% and 81.2% for Amberlyst A21, Amberlite HPR 900 OH and Amberlite IRA958 Cl, respectively. As the regenerant HCl concentration increased from 1 to 10%, calculated succinic acid separation efficiencies decreased from 80.3 to 70.7%. Notably, as the regenerant strength increased from 1 to 10%, the total amount of organic acids desorbed from the resin sharply increased. At operation temperatures of 20, 30 and 40°C, SA separation efficacies were 81.2%, 73.9% and 76.4%, respectively. The insights from this study will be of great value in design of chromatographic separation systems for organic acids.

The quantitative content determination of main groups of biologically active substances in batches of Viburnum opulus fruits

Aim. To determine the quantitative content of the main groups of biologically active substances (BAS) in batches of Viburnum opulus fruits using pharmacopeial methods for their subsequent use in the standardization of the plant raw material.Materials and methods. For the study, 6 batches of air-dried Viburnum opulus fruits crushed to a particle size of 1 – 2 mm and harvested in different regions of Ukraine in the mass fruiting phase in October-November 2020 were used. The quantitative determination of polyphenols and tannins was performed using the spectrophotometric method at a wavelength of 760 nm calculated with reference to pyrogallol and dried substance. The total amount of hydroxycinnamic acids was determined according to the method of the SPhU (State Pharmacopoeia of Ukraine) 2.0 described in the monograph “Kidney TeaN” calculated with reference to rosemary acid. The total amount of organic acids was determined by the titrimetric method according to the method of the monograph of the SPhU 2.1 “Rose hipsN” calculated with reference to malic acid.Results and discussion. The quantitative content of polyphenols (calculated with reference to pyrogallol and dried substance) in batches of Viburnum opulus fruits varied by about 1.4 times from 1.74 ± 0.01 % to 2.36 ± 0.01 %. According to the results obtained, the quantitative content of tannins (calculated with reference to pyrogallol and dried substance) in batches of Viburnum opulus fruits varied by 1.7 times from 0.73 ± 0.01 % to 1.23 ± 0.01 %. The quantitative content of the total amount of hydroxycinnamic acids calculated with reference to rosemary acid in batches of Viburnum opulus fruits ranged by 1.2 times from 3.96 ± 0.01 % to 4.73 ± 0.01 %. The quantitative content of the total amount of organic acids calculated with reference to malic acid in batches of Viburnum opulus fruits fluctuated more than 1.3 times from 6.80 ± 0.01 % to 9.08 ± 0.01 %.Conclusions. The quantitative content of the main groups of biologically active substances has been determined in 6 batches of Viburnum opulus fruits harvested in different regions of Ukraine using pharmacopoeial methods: polyphenols (varied by 1.4 times), tannins (varied by 1.7 times), the total amount of hydroxycinnamic (varied by 1.2 times), and the total amount of organic acids (varied by 1.3 times) calculated with reference to dried substance. The content of the groups of biologically active substances in batches of Viburnum opulus fruits slightly correlates with the place of the raw material harvesting. Thus, the selected methods of the SPhU 2.0 are quite suitable for determining the quantitative content of polyphenols, tannins and of the total amount of hydroxycinnamic and organic acids in batches of Viburnum opulus fruits; they can be used in further studies to standardize the raw material.

Isolation, Mutagenesis, and Organic Acid Secretion of a Highly Efficient Phosphate-Solubilizing Fungus.

The highly effective phosphate-solubilizing microorganisms are significant for making full use of the potential phosphorus resources in the soil and alleviating the shortage of phosphorus resources. In this study, a phosphate-solubilizing fungus was isolated from wheat and cotton rhizosphere soils in the lower reaches of the Yellow River in China and was identified as Penicillium oxalicum by morphological and ITS sequencing analysis. In order to obtain a fungus with more efficient phosphorus solubilization ability, we tested three positive mutant strains (P1, P2, and P3) and three negative mutant strains (N1, N2, and N3) through low-energy nitrogen ion implantation mutagenesis. Compared with the parental strain, the phosphate-solubilizing capacity of P1, P2, and P3 was enhanced by 56.88%, 42.26%, and 32.15%, respectively, and that of N1, N2, and N3 was weakened by 47.53%, 35.27%, and 30.86%, respectively. Compared with the parental strain, the total amount of organic acids secreted significantly increased in the three positive mutant strains and decreased in the negative mutant strains; the pH of culture medium was significantly lower in the positive mutant strains and higher in the negative mutant strains. The capacity of phosphate-solubilizing fungus to secrete organic acids and reduce the growth-medium pH was closely related to its phosphate-solubilizing ability. The changes in the amount of organic acids secreted by mutants can alter their acidification and phosphate-solubilizing capacity. In conclusion, this study offers a theoretical basis and strain materials for the exploration and application of phosphate-solubilizing fungi.

Fermentation process optimization and chemical composition analysis on black tea wine

In this study, the fermentation process of black tea wine was optimized, and the changes in catechins, organic acids, and aroma components during fermentation were investigated. The optimal fermentation conditions for tea wine were determined as follows: the addition of 15% sucrose and 0.75% tea leaves, and a fermentation temperature of 25 ºC. Under the optimal conditions, the alcohol content and sensory evaluation score of tea wine were 8.9 %ABV and 88, respectively. The contents of catechins and organic acids in tea wine were 21.29 mg/L and 3.68 mg/mL, which were 1.32-fold and 10.51-fold higher than those of tea infusion, respectively. L-malic acid was the main organic acid in tea wine, which accounted for 56.3% of the total amount of organic acids. A total number of 34 and 33 kinds of aroma components were detected in tea wine and tea infusion, respectively. The main aroma components of tea wine were esters and alcohols, which accounted for 39.7% and 45.9% of the total amount of aroma components, respectively, while the main aroma components of tea infusion were esters and aldehydes, accounting for 34.6% and 33.2%, respectively.

Fermentation of high-salt liquid-state soy sauce without any additives by inoculation of lactic acid bacteria and yeast.

Food additives are artificial or natural substances that are added to food to improve the color, aroma, taste, and other qualities, and to meet processing requirements. For the concern of food health and safety, brewed soy sauce without additives has attracted consumers' attention. Here, only four necessary raw materials including soybean, wheat, salt, and water were added. High-salt soy sauce fermentation was conducted for six months by sequential inoculation of lactic acid bacteria and yeast under different brine content (18%, 20%, and 22%). By analyzing the physicochemical indicators during moromi, three soy sauces (No. 1: 18% salt, inoculated with Tetragenococcus halophilus and Zygosaccharomyces rouxii, No. 5: 20% salt, inoculated with T. halophilus and Z. rouxii, No. 11: 22% salt, inoculated with T. halophilus and Candida versatilis) were selected and sterilized to produce finished products for further comparative investigation. Results showed that the flavor components of these three soy sauces were richer in variety than the commercial soy sauces and No. 11 soy sauce was detected to have the largest total amount of organic acids. Plate count agar analysis revealed that the free amino acid differences of soy sauces were distinct, among which the No. 11 soy sauce had the highest glutamate content of 19.64 g L-1. Besides, it was found that the shelf life of these three soy sauces could reach two years at 4 ℃. This study suggests that the high-salt soy sauce made by rational application of lactic acid bacteria, yeast, and effective sterilization can have high quality and long shelf life without adding any additives.

Bioleaching of Major, Rare Earth, and Radioactive Elements from Red Mud by using Indigenous Chemoheterotrophic Bacterium Acetobacter sp.

The aim was to study the bioleaching performance of chemoheterotrophic bacterium involved in leaching of major, rare earth, and radioactive elements from red mud (RM), and to explore the underlying mechanism. An acid-producing bacterium, identified as Acetobacter sp., was isolated from RM impoundment and used in the bioleaching experiments under one-step, two-step and spent medium process at up to 10% pulp density. The results showed that the leaching ratios of Al, Lu, Y, Sc, and Th were 55%, 53%, 61%, 52%, and 53% respectively under one-step process at 2% pulp density. Under both one- and two-step processes at 2% pulp density, the radioactivity of bioleached RM can meet the relevant regulation in China. The total amount of organic acids excreted by Acetobacter sp. increased with an increase of RM pulp density. After bioleaching, contents of hematite and gibbsite decreased but perovskite increased in RM. Micromorphology analysis indicated that the cells of Acetobacter sp. adhered to RM particles and formed large-size aggregates, and a new crystal of weddellite emerged. In view of the shorter lag phase and smaller biomass comparing to fungi even under direct contact with RM, bacterium Acetobacter sp. is supposed to apply to in situ heap or dump bioleaching of RM.

РЕАЛИЗАЦИЯ ПРОДУКТИВНЫХ КАЧЕСТВ КОРОВ СИММЕНТАЛЬСКОЙ ПОРОДЫ ПРИ СБАЛАНСИРОВАННОМ КОРМЛЕНИИ

The realization of genetic potential of dairy cattle today is primarily associated with balanced feeding, which can be provided only with high quality bulky feed. In 2016, 2500 t of silage of corn fresh yield at the milk-wax stage of ripeness with a new biological preservative (based on lactic and propionic acid bacteria, 3 g/t) and 4000 t of preserved silage were tested at “Roshcha” LLC in Bazarno-Karabulaksky district of Saratov region. The silage with the new biological preservative significantly improved after storage, compared with the preserved silage: pH - 4.1; total amount of organic acids - 2.80%, content of lactic acid in the total amount of acids - 2.10%, acetic acid - 0.70%, no butyric acid, content of lactic and acetic acids in the total amount - 75 and 25% respectively. The test conducted on lactating cows during the first lactation phase showed that a diet with silage prepared with the biological preservative increased daily yield of 4 % milk by 6,7 % as compared with the control (p < 0.05). Biochemical blood parameters of the cows of the test group indicated the improvement of anabolic processes, it provided an increase in milk productivity. The additional profit after sales of milk obtained from the test group was 3325.5 rubles/animal. To balance the diet of cows in energy and nutrients and to fulfill the productive potential of cows, it is necessary to improve feed base, taking into account available technologies, and to improve quality of bulky feed by using new biological preservatives.

Bioactive compounds and antioxidant potential in tomato pastes as affected by hot and cold break process.

The effects of hot and cold break industrial tomato paste production steps on phenolic compounds, carotenoids, organic acids, hydroxy methyl furfural (HMF) and other quality parameters of tomato pastes were investigated in this study. Phenolic compounds, carotenoids, organic acids, and HMF analyses were performed with LC-DAD-ESI-MS/MS and LC-DAD-RID was used for the sugar analyses. Furthermore, the antioxidant capacities of tomato pastes were assessed via the DPPH and ABTS methods. The increase of phenol acids at the processing steps of cold break production method was higher than the hot break production method. According to PCA analyses, phenolic acids characterized cold break tomato pastes while hot break tomato pastes were characterized by flavanols and flavanones. The total amount of organic acids decreased with processing and the loss of organic acids was lower in cold break pastes. Heating and evaporation were determined as the most important processing steps in which the amount of different quality parameters change.

흑마늘의 첨가량과 초기 알코올 농도를 달리한 발효 식초의 품질특성

The quality characteristics of black garlic vinegar produced by acetic acid fermentation were analyzed over a 25 day period. Black garlic vinegar was produced using black garlic 3, 6, 9 and 12 folds with water, and initial alcohol concentrations of 6~12%. The pH values of the vinegar samples were in range of 3.85~4.46 after 25 days fermentation, and the sugar contents were highest after 9 days of fermentation (12.00~13.50 °Brix). The total polyphenol concents of vinegars were in the range of 20.65~52.04 mg/100 mL 25 days fermentation. Pyrogallol and vanillic acid were detected in the completely fermented vinegars, and their contents increased with black garlic content. Five organic acids (lactic acid, acetic acid, citric acid, succinic acid and propionic acid) were detected after 25 days of fermentation, with the total amount of organic acids being 5,327.34~6,307.64 mg/100 mL, and the total abetic acid contents beging the highest of the organic acids at 4208.90~5,570.29 mg/100 mL. After 25 days of fermentation, the total minerals contents were higher, and depending on the quantity of black garlic added. Of the minerals, the of potassium content was the highest (366.23~1,619.67 mg/L).

Study for quality and amount of carbonic acids in the leaves of Urtica dioica L.

Search and elaboration of plant-based drugs which stimulate physiological functions of organism are key trend of current scientific researches.Aim. The identification and analysis of organic and fatty acids amount by gas chromate-mass-spectrometry on the chromatograph Agilent Technology 6890N with mass-spectrometric detector 5973N, has been performed to assess the amount of some species of carbonic acids in the leaves of Urtica dioica.Methods and results. Components have been identified accordingly to the comparison results of mass-spectra substances separated within chromatography with the data in references for mass-spectra NIST02 and WILEY 2007. 14 Organic and 17 fatty acids have been identified. Citric acid predominated in organic acids (50.65%), palmitic (33.19%), linolenic (32.50%), linoleic (20.27%) were prevailing in fatty acids. The total amount of organic acids was 1776.6 mg/kg, fatty ones was 15731.9 mg/kg.Conclusion. The obtained results convinced that researches on raw materials from Urtica dioica as a source of natural biologic substances for manufacturing mono-and polycomponent phytodrugs are promising.

The quantitative content of the main groups of biologically active substances in the bay laurel raw materiaL

The study of the chemical composition of the bay laurel raw material has shown that the plant raw material contains such groups of biologically active substances (BAS) as carbohydrates, fatty and amino acids, phenolic compounds revealing a wide spectrum of the biological activity. The data concerning the chemical composition of the bay laurel raw material is not enough described in the literature sources. The content of the main BAS in different samples of bay laurel shoots and leaves has been determined. The content of the total amount of organic acids, the total amount of oxidizable phenols, the total amount of hydroxycinnamic acids and the total amount of flavonoids in the bay laurel leaves samples are slightly higher. The content of the total amount of organic acids in shoots is not less than 1.7%, in leaves – not less than 1.9%. The content of the total amount of oxidizable phenols in both types of the raw material is not less than 4.5%, the total amount of hydroxycinnamic acids – not less than 1.3%, the total amount of flavonoids – not less than 0.8%. The standardization parameters for the bay laurel raw material have been determined on the basis of the research conducted. The results obtained will be used for developing the project of quality control methods “Lauri Cormus”. The profound research of the medicinal plant raw material previously studied for the potential expansion of the aspects of its application is a topical task of modern pharmacy. Our attention was attracted to plants of the Lauraceae family, Laurus L. genus combining 3 species – Laurus azorica (Seub.) Franco, Laurus nobilis L., Laurus porrecta Roxb. (the latter species is related to Cinnamomum genus, Cinnamomum porrectum (Roxb.) Kosterm. species) [3]). The most wide-spread species is bay laurel – an evergreen tree or a shrub up to 10 m high. Bay laurel fruits were included into 6 pre-revolutionary editions of the Russian Pharmacopoeia, and the State Pharmacopoeia of the USSR, the 1 st ed. Its leaves are used in the treatment of throat cancer, psoriasis, arthritis, pain in joints, cramps, diabetes. The bay laurel oil obtained with flax or sunflower oil is used in the cases of paralysis, rheumatism, etc. The essential oil from leaves contains 1,8-cineol, terpinen-4-ol, α-pinene, β-pinene, linalool acetate [15], as well as β-cymene, β-longipirene, cadinene, α-terpinyl acetate, α-balnesene [12]. BAS of bay laurel are considered to reveal wound-healing [14], anti-inflammatory [10], antinociceptive [10], immune stimulating [5], neuroprotective [11, 14], anticholinergic [14], anti-oxidant [6, 8, 9, 13], anti-ulcer, anti-convulsant, antimutagenic [14], insecticidal [4], antibacterial [7, 14], antiviral, antifungal [14], larvicidal [15] activities. At the same time bay laurel is contraindicated in the cases of glomerulonephritis, pregnancy, tendency to bleedings, amyloidosis. Moreover, medicines produced from this plant are absent nowadays. Thus, the profound studies of the bay laurel raw material and creation of new substances on its basis are up to date.

Online atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-IT-MS&amp;lt;sup&amp;gt;n&amp;lt;/sup&amp;gt;) for measuring organic acids in concentrated bulk aerosol – a laboratory and field study

Abstract. The field application of an aerosol concentrator in conjunction with an atmospheric pressure chemical ionization ion trap mass spectrometer (APCI-IT-MS) at the boreal forest station SMEAR II at Hyytiälä, Finland, is demonstrated in this study. APCI is a soft-ionization technique allowing online measurements of organic acids in the gas and particle phase. The detection limit for the acid species in the particle phase was improved by a factor of 7.5 to 11 (e.g. ∼40 ng m3 for pinonic acid) by using the miniature versatile aerosol concentration enrichment system (mVACES) upstream of the mass spectrometer. The APCI-IT-MS was calibrated in the negative ion mode with two biogenic organic acid standards – pinic acid and pinonic acid. Pinic acid was used as a surrogate for the quantification of the total amount of organic acids in the ambient aerosol based on the total signal intensities in the negative ion mode. The results were compared with the total organic signal of a C-ToF-AMS during the HUMPPA-COPEC 2010 field campaign. The campaign average contribution of organic acids measured by APCI-IT-MS to the total submicron organic aerosol mass was estimated to be about 60%, based on the response of pinic acid. Very good correlation between APCI-IT-MS and C-ToF-AMS (Pearson's R = 0.94) demonstrates soft-ionization mass spectrometry as a complimentary technique to AMS with electron impact ionization. MS2 studies of specific m/z ratios recorded during the HUMPPA-COPEC 2010 field campaign were compared to MS2 studies of selected monoterpene oxidation products formed in simulation chamber experiments. The comparison of the resulting fragments shows that oxidation products of the main VOCs emitted at Hyytiälä (α-pinene and Δ3-carene) cannot account for all of the measured fragments. Possible explanations for those unaccounted fragments are the presence of unidentified or underestimated biogenic SOA precursors, or that different products are formed by a different oxidant mixture of the ambient air compared to the chamber ozonolysis.

Root Exudates and Nitrogen Uptake of Wheat in Wheat/Maize/Soybean Relay Cropping System

Root exudates play a role in adjusting physical and chemical characteristics of soil, improving soil fertility, and facilitating nutrient uptake. Thus, they are used to explaining the mechanism of high nutrient utilization efficiency for plants. In the relay cropping system of wheat/maize/soybean, nitrogen use efficiency appears higher than that in the cropping system of wheat/maize/sweet potato. For explaining the relationship between the high use efficiency of nitrogen and the effects of rhizosphere microenvironment in the wheat/maize/soybean cropping system, the characteristics of wheat root exudates as well as its effects on wheat roots, wheat rhizosphere soil, and nitrogen uptake in wheat were studied in a two-year continuous experiment from 2006 to 2008 with four cropping systems, including two sole cropping systems (wheat–soybean and wheat–sweet potato) and two rely cropping systems (wheat/maize/soybean and wheat/maize/sweet potato). In the wheat/maize/soybean system, the soil moisture, soil pH and soil quick-acting N (NO3?-N and NH4+-N) content at wheat rhizosphere reduced at both flowering and ma-turity stages, and the total nitrogen uptake in shoots, root activity, root dry matter weight and soil total nitrogen content of wheat increased. At flowering stage, the total amount of organic acids and the content of soluble sugar of wheat rhizosphere increased in the wheat/maize/soybean system. The total amount of organic acid and the content of soluble sugar of wheat were higher in relay cropping system than in sole cropping system. In the two sole cropping systems, the wheat–soybean mode had higher amount of organic acid and higher content of soluble sugar than wheat–sweet potato. Wheat plants from fringe rows could exude organic acids and higher soluble sugar content than those from central rows, and the amount of root exudates in fringe rows was the high-est among all the cropping systems. At jointing stage, the content of acetic acid in the sole cropping systems increased, which accounted for 47.8% to 51.6% of the total of organic acid. The content of citric acid in the relay cropping systems increased from 31.7% to 55.1% of total organic acid. At flowering stage, the content of acetic acid in sole and relay cropping systems was also promoted from 33.3% to 78.3% of the total organic acid. The root exudates were in favor of improving root growth condition, activating soil nutrition, enhancing nitrogen uptake and increasing nitrogen use efficiency in the wheat/maize/soybean relay crop-ping system.

Gene deletion of cytosolic ATP: citrate lyase leads to altered organic acid production in Aspergillus niger

With the availability of the genome sequence of the filamentous fungus Aspergillus niger, the use of targeted genetic modifications has become feasible. This, together with the fact that A. niger is well established industrially, makes this fungus an attractive micro-organism for creating a cell factory platform for production of chemicals. Using molecular biology techniques, this study focused on metabolic engineering of A. niger to manipulate its organic acid production in the direction of succinic acid. The gene target for complete gene deletion was cytosolic ATP: citrate lyase (acl), which had previously been identified by using genome-scale stoichiometric metabolic model simulations. The acl gene was deleted using the bipartite gene-targeting method, and the mutant was characterized in batch cultivation. It was found that the succinic acid yield was increased threefold by deleting the acl gene. Additionally, the total amount of organic acids produced in the deletion strain was significantly increased. Genome-scale stoichiometric metabolic model predictions can be used for identifying gene targets. Deletion of the acl led to increased succinic acid production by A. niger.

Vertical profiles of low molecular weight organic acids in sediment porewaters of six Chinese lakes

Summary The composition and contents of low molecular weight organic acids (LMWOAs) were determined, their contributions to dissolved organic carbon (DOC) and vertical profiles were investigated in sediment porewaters of six lakes, China: Lake Sihai-Longwan (SHLW), Lake Bosten (BST), Lake Qinghai (QH), Lake Chenghai (CH), Lake Erhai (EH) and Lake Dianchi (DC). The sources and behaviors of LMWOAs during early diagenesis were also discussed. The results show that up to eight species of LMWOAs were detected in those sediment porewaters: lactic acid, acetic acid, formic acid, methanesulfonic acid (MSA), pyruvic acid, trifluoroacetic acid (TFA), sorbic acid and oxalic acid; acetic acid was the predominant species. The contents of organic acids in six lakes decrease in the rank order of QH > SHLW > BST > EH > DC > CH, with the total amount of organic acids in the northern lakes being about 27 times higher than those in the southern lakes. In total amounts of various organic acids, acetic acid were the highest and MSA was the lowest, they were 62.7 and 0.3 μM, respectively. The highest total amount of organic acids was in QH, with the average value of 92.0 μM and the contribution to DOC was 10.9% followed by SHLW, BST, EH and DC, which were 43.7 μM, 2.7%; 42.3 μM, 5.6%; 5.6 μM, 1.1%; 4.4 μM, 0.7%, respectively. Organic acid was the lowest in CH, with the average value of 0.5 μM and the contribution to DOC was just 0.04%. The main organic acids were acetic acid, pyruvic acid, sorbic acid and formic acid in SHLW, BST, DC and CH, lactic acid in both EH and QH. Vertical profiles of LMWOAs varied among different species and lakes due to the sources and complex microbial processes in early diagenesis. This study suggests LMWOAs played a significant role in the sources and transformation of DOM in the sediments in lakes.

Effects of the Tomato Pathogen Fusarium oxysporum f. sp. radicis-lycopersici and of the Biocontrol Bacterium Pseudomonas fluorescens WCS365 on the Composition of Organic Acids and Sugars in Tomato Root Exudate

The effects of the pathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici and of the bacterial biocontrol strain Pseudomonas fluorescens WCS365, and of both microbes, on the amounts and composition of root exudate components of tomato plants grown in a gnotobiotic stonewool substrate system were studied. Conditions were selected under which introduction of F. oxysporum f. sp. radicis-lycopersici caused severe foot and root rot, whereas inoculation of the seed with P. fluorescens WCS365 decreased the percentage of diseased plants from 96 to 7%. This is a much better disease control level than was observed in potting soil. Analysis of root exudate revealed that the presence of F. oxysporum f. sp. radicis-lycopersici did not alter the total amount of organic acids, but that the amount of citric acid decreased and that of succinic acid increased compared with the nontreated control. In contrast, in the presence of the P. fluorescens biocontrol strain WCS365, the total amount of organic acid increased, mainly due to a strong increase of the amount of citric acid, whereas the amount of succinic acid decreased dramatically. Under biocontrol conditions, when both microbes are present, the content of succinic acid decreased and the level of citric acid was similar to that in the nontreated control. The amount of sugar was approximately half that of the control sample when either one of the microbes was present alone or when both were present. Analysis of the interactions between the two microbes grown together in sterile tomato root exudate showed that WCS365 inhibited multiplication of F. oxysporum f. sp. radicis-lycopersici, whereas the fungus did not affect the number of CFU of the bacterium.