Soluble Protein Nitrogen Research Articles

Water-Nutrient Coupling Strategies That Improve the Carbon, Nitrogen Metabolism, and Yield of Cucumber under Sandy Cultivated Land

The purpose of this study was to explore the carbon and nitrogen metabolism mechanisms of sand-cultivated cucumbers under different deficit irrigation–nitrogen management strategies and provide a theoretical basis for their greenhouse management. This study set up two factors, the deficit irrigation level and the nitrogen application rate, and conducted an experiment on deficit irrigation–nitrogen coupling of sand-cultivated cucumbers using a quadratic saturation D–optimal design. Seven treatments were set up in the experiment, to measure the soluble sugar and protein contents, as well as the activity of key enzymes for carbon and nitrogen metabolism at five different growth stages. The results indicate that the 80% irrigation with 623 kg N hm−2 (IN4) treatment significantly improved the soluble sugar, protein, and actual leaf nitrogen contents of cucumber at the five different growth stages and, as a result, achieved higher sucrose synthase (SS) and sucrose phosphate synthase (SPS) activities in the cucumber leaves. Furthermore, such improvements were due to the reduction in oxidative damage of sand–cultivated cucumber at various growth stages. The IN4 and 89% irrigation with 1250 kg N hm−2 (IN5) treatments significantly increased the activities of RuBisCO, catalase (CAT), peroxidise (POD), and superoxide dismutase (SOD) at various growth stages of sand-cultivated cucumber. The higher activities of glutamate dehydrogenase (GLDH), glutamate synthase (GOGAT), nitrate reductase (NR), glutamine synthase (GS), acid invertase enzyme (AIE), neutral invertase enzyme (NIE), and better antioxidative enzyme activities were recorded under the IN4 treatments at various growth stages, which effectively improve (69.6%) cucumber yield. The soil properties, carbon and nitrogen metabolism, and antioxidant metabolism were positively correlated with sand-cultivated cucumber yield in a greenhouse. We concluded that the IN4 treatment was the better deficit irrigation–nitrogen management strategy because it considerably improves carbon and nitrogen metabolism, antioxidant enzyme activities, and sand–cultivated cucumber yield in a greenhouse.

Solid-State Fermentation with White Rot Fungi (Pleurotus Species) Improves the Chemical Composition of Highland Barley Straw as a Ruminant Feed and Enhances In Vitro Rumen Digestibility.

Lignin degradation is important for enhancing the digestibility and improving the nutritive quality of ruminant feeds. White rot fungi are well known for their bioconversion of lignocellulosic biomass. The objective of this paper was to evaluate whether Lentinus sajor-caju, Pleurotus ostreatus, Phyllotopsis rhodophylla, Pleurotus djamor, Pleurotus eryngii, and Pleurotus citrinopileatus treatments altered the chemical compositions of highland barley straw constituents and enhanced their nutritional value as a ruminant feed. All white rot fungi significantly increased the relative crude protein (CP), ethyl ether extract (EE), starch, soluble protein (SP), and non-protein nitrogen (NPN) contents but decreased the ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and acid detergent insoluble protein (ADFIP) contents. In addition, L. sajor-caju treatment increased (p < 0.001) the levels of PA, PB2, PB3, CA, CB1, CB2, and CNSC, but reduced (p < 0.001) the PC and CC in the solid-state fermentation of highland barley straw. Maximum ligninlysis (50.19%) was optimally produced in the presence of 1.53% glucose and 2.29% urea at 22.72 ℃. The in vitro dry matter digestibility and total volatile fatty acid concentrations of fermented highland barley straw, as well as the fermentability, were optimized and improved with L. sajor-caju, which degraded the lignocellulose and improved the nutritional value of highland barley straw as a ruminant feed.

Effects of Fertilization Mode on the Growth of Lactuca sativa L. and Soil Nutrients in Facilitated Cultivation

This paper aims to find a fertilization method that better matches the growth characteristics of vegetables and reduces the soil and environmental problems caused by unreasonable fertilization methods, in view of the strong buffering of the clayey black soil in the north and the mismatch between the amount of chemical fertilizer applied and the growth characteristics of vegetables during cultivation. In this experiment, Lactuca sativa L. (Lactuca sativa) was studied in a randomized complete block design in greenhouse and five different fertilizer application methods were arranged: exponential fertilization (EF), linear fertilization (LF), average fertilization (AF), one-time fertilization (OF), and no fertilization as a control group (CG). The effects of different fertilization methods on soil nutrients, agronomic traits of Lactuca sativa growth, and related quality were investigated, and the pattern of effects of different fertilization methods on growth and soil nutrients was obtained. The results of the experiment showed that the exponential fertilization method gradually took advantage as the growth time extended. The plant height (PLH), leaf length (LL), leaf width (LW), yield, soluble protein (SP), soluble sugar (SS), vitamin C (VC), and elemental nitrogen (EN) and potassium (EK) of Lactuca sativa were significantly improved under the exponential fertilization method compared with other fertilization methods, by 29.9 cm, 51.5 cm, 5.96 cm, 22, 2.32 kg/m2, 0.23%, 0.44%, 3.93%, 94.66 mg/kg, 1.58 g/kg, and 1.94 g/kg, respectively. The alkali-hydrolyzed nitrogen (SAN), available phosphorus (SAP), and available potassium (SAK) in the soil after fertilization were 139.69 mg/kg, 50.23 mg/kg, and 180.30 mg/kg, respectively. The above results showed that the exponential fertilization method not only improved the quality of Lactuca sativa and thus the quality of the crop growth traits, but also changed the soil nutrients favorably after fertilization, which is of some importance for the protection of black soils.

Studies on the Malting Parameters of Two Acha Species Digitaria exilis and Digitaria iburua

The malting parameters of two acha species (Digitaria exilis-white and Digitaria iburua-black), a small annual herbaceous indigenous African cereal grain were studied. This study was aimed at assessing the brewing potential of the two acha species. The research was carried out in Microbiology Laboratory of Nnamdi Azikiwe University, Awka. The brewing properties assessed were; moisture content, cold water extract, hot water extract, diastatic power, total nitrogen, cold water soluble protein, total soluble protein and free amino nitrogen. Extraction, digestion, titration, colorimetric and spectrophotometric methods were used to assess the above brewing properties. The moisture content of the white species malt (11.0 - 12.4%) was higher than that of the black (10.3 – 11.2%) and increased with germination time but decreased after the peak (4th) day. The lower moisture content of the black acha malts gave a resultant effect of more extract production from cold water extract ( CWE 27.5, 30.10%), hot water extract (HWE 278, 304ol/kg) and diastatic power (DP 19 ,23oL) of the two acha malts on the fourth (peak) day of germination. The peak values for total nitrogen (1.6, 1.75%), cold water soluble protein (120, 128%), total soluble protein (6.2, 7.5%) and free amino nitrogen (FAN 105, 114.5%) were also higher for the black acha on the peak day of germination. The correlation studies between the HWE (R2=0.9903, 0.9551), Cold water soluble protein (CWS-P- R2= 0.9809, 0.9285) and Diastatic power for the black and white species, respectively, were positively significant depicting a strong relationship between the correlated parameters. The black acha malt recorded more extract yield than the white acha and the result of the two acha species assessed showed that they possess brewing properties.

Microbial Community Succession and Its Correlation with Quality Characteristics during Gray Sufu Fermentation.

Gray sufu, a traditional fermented food derived from soybeans, undergoes a complex fermentation process. This study aimed to investigate the dynamics of the microbial community during sufu fermentation and its relationship with key quality characteristics. Through systematic sampling of sufu at different phases of fermentation, 143 bacterial genera and 84 fungal genera involved in the process were identified. Among these, Chishuiella, Enterococcus, Lactococcus, and Weissella emerged as the predominant bacterial communities. After seven days of ripening fermentation, Trichosporon supplanted Diutina as the predominant fungus, accounting for more than 84% of all fungi. Using redundancy analysis, significant correlations between microbiota and physicochemical properties were uncovered. Chishuiella and Empedobacter displayed positive relationships with pH, soluble protein, and amino nitrogen content. In addition, five biogenic amines were detected, and it was determined that tyramine accounted for more than 75% of the total biogenic amines in the final gray sufu products. Spearman correlation analysis revealed significant positive relationships between Lactococcus, Enterococcus, Tetragenococcus, Halanaerobium, and Trichosporon and the five biogenic amines examined. These findings shed light on the complex interactions between microorganisms and biogenic amines during the fermentation of gray sufu, thereby facilitating the development of microbial regulation strategies for better quality control.

Melatonin improves drought stress tolerance of pepper (Capsicum annuum) plants via upregulating nitrogen metabolism.

While ameliorating effects of melatonin (MT) on abiotic stress tolerance in plants are widely reported, the mechanism that underlies this process remains elusive. This work investigated mechanisms by which MT improved drought tolerance in pepper (Capsicum annuum ) plants. A foliar spray of 0.1mM MT treatment was applied to plants grown at 80% and 40% of full field capacity for 3days. Drought stress caused a significant decrease in plant dry weight, relative water content, leaf water potential, PSII efficiency (F v /F m ratio), chlorophyll, soluble protein, leaf and root nitrogen content. Drought increased hydrogen peroxide, malondialdehyde (MDA), nitrate, ammonium, free amino acids, soluble sugars, proline and glycine betaine. Drought also increased peroxidase (POD), glutathione S-transferase (GST) and catalase (CAT) activities, electrolyte leakage (EL) and methylglyoxal (MG). MT pre-treatment reduced oxidative stress and improved nitrogen metabolism by activating various enzymes such as nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthetase (GOGAT) and glutamine dehydrogenase (GDH) activities. It also activated enzymes related to the glyoxalase system (Gly I and Gly II) and decreased NO3 - , NH4 + and free amino acid content. Our study suggests a cost-effective and sustainable solution to improve crop productivity in water-limited conditions, by enhancing plant growth, photosynthesis and nitrogen content.

Effect of starter cultures on dynamics succession of microbial communities, physicochemical parameters, enzyme activities, tastes and volatile flavor compounds during sufu fermentation

This study was to investigate dynamic changes of microbial communities, physicochemical parameters, enzyme activities, tastes and volatile flavor compounds of sufu fermented by different starters during sufu fermentation. The results showed that sufu inoculated starter cultures B (MSC-B) consisted of Rhizopus oligosporus, Mucor 40,899, Saccharomyces cerevisiae and Lactobacillus bulgaricus with a ratio of 4:2:2:1 had higher contents of soluble protein and amino nitrogen as well as superior activity of protease, glucoamylase and lipase. Correlation analysis demonstrated that the three starters were significantly positive correlated with total acid, amino acid nitrogen and soluble protein. In addition, using MSC-B to produce sufu, aspartic increased by 17.5-fold. Moreover, fruity smell and burnt sugar flavor were the key volatile flavor compounds for sufu fermented by MSC-B in the pre-fermentation. Alcohols became the predominant volatile flavor compounds in the post-fermentation for the three starter cultures. In conclusion, MSC-B is of great potential in the application of sufu industry. Our work will provide a theoretical reference for the development of new mixed - starter cultures in sufu.

Lettuce growth, morphology and critical leaf trait responses to far-red light during cultivation are low fluence and obey the reciprocity law

The mediating role of far-red (FR) light at the end of day (EOD) during cultivation on plant growth, morphology and critical leaf traits was analyzed. Three experiments were conducted on lettuce. Firstly, it was clarified whether or not the FR light effect depends on the presence of photosynthetic active radiation (PAR). Secondly, dose-response curves were obtained by applying six FR light intensities. Eventually, three FR light intensities were applied for different durations in a way that daily light integral (DLI) remained constant. Assessments included specific leaf area, dry mass partitioning, leaf optical properties, net photosynthesis rate (Pn), as well as leaf photosynthetic pigment, soluble sugar, starch, cellulose, soluble protein, nitrate, total nitrogen and total carbon contents. Pn was not significantly affected by FR light during growth, despite decreased leaf light absorption and photosynthetic pigment content (2 and 16%, respectively). Starch and nitrate contents were not affected by FR light, whereas cellulose, soluble protein and total nitrogen contents were generally decreased. When applied alone, FR light better promoted growth, radiation use efficiency (∼22%) and soluble sugar content (∼34%). The FR light-induced effect was intensity-dependent, while both qualitative and quantitative threshold responses were apparent depending on the trait. Five minutes of daily exposure to FR light (90 μmol m − 2s − 1) were adequate in eliciting the photomorphogenic responses. Notably, no significant differences were observed in all traits between FR light intensities under the same DLI. In conclusion, FR light at the EOD better stimulates growth when applied alone, through improved light interception. FR light response is low fluence and depends on the DLI, obeying the reciprocity low.

Effect of kernel breakage on the fermentation profile, nitrogen fractions, and in vitro starch digestibility of whole-plant corn silage and ensiled corn grain

The objective of this experiment was to analyze the effect of kernel breakage on the fermentation profile, nitrogen fractions, and ruminal in vitro starch digestibility of whole-plant corn silage and ensiled corn grain. Whole corn plants were harvested, and ears were separated from the forage portion and shelled. Corn kernels were either left intact or broken manually using a hammer. The remaining forage portion of the corn plants was chopped. Samples of the intact and broken kernels were stored for 0 or 30 d in quadruplicate vacuum pouches. Remaining intact and broken kernels were each reconstituted with the chopped forage portion of the corn plant to simulate whole-plant corn forage and were also stored for 0 or 30 d. In kernels separated from whole-plant corn silage, kernel form had no effect on zein protein concentrations. However, it was observed that in vitro starch digestibility at 7 h increased with ensiling only in kernels that were broken. When corn kernels were ensiled alone, concentrations of soluble crude protein and ammonia nitrogen increased with ensiling to a greater extent when kernels were broken. Finally, fermentation of ensiled corn grain was enhanced when kernels were broken. Overall, this study gives insight into the importance of kernel breakage to improve starch digestibility in corn silage through means other than a reduction in particle size and opens the door for continued investigation into the proteolytic activity occurring in the silo.

Cutting test of Catalpa bungei and change analysis of cutting contents

Objective The objective of this study is to explore the rooting mechanism of Catalpa bungei, as well as the morphological characteristics and physiological and biochemical characteristics of cuttings during rooting process. Method The cuttings of C. bungei were treated with dissolved GGR-6 to promote rooting, and the enzyme activities, nutrients and rooting inhibitors in different rooting stages were measured. Result GGR-6 treatment significantly promoted the rooting of cuttings, and the rooting rate reached 82.04%, higher than that of the control treatment (P＜0.01). During the rooting process, the activities of superoxide dismutase (SOD), peroxidase (POD) and polyphenol oxidase (PPO) increased during the formation of a large number of callus, and the maximum values of SOD and PPO were 623.33×16.67 and 57.44×16.67 nkat·g−1, respectively. POD activity decreased during the formation of adventitious roots, and the three enzymes were positively correlated with the rooting rate. The soluble sugar and C/N ratio in cuttings decreased sharply at the callus stage, only about 40% of the initial value, and reached the maximum at 20 days of cutting. The soluble protein and total nitrogen showed a decreasing trend, and reached the minimum at 25−30 days. Under GGR-6 treatment, the change range of nutrients in cuttings was large, and the maximum values were higher than those of the control. Total nitrogen content was negatively correlated with rooting rate (P＜0.05), while soluble sugar, soluble protein and C/N were significantly positively correlated with rooting rate (P＜0.05). GC-MS analysis identified four rooting related substances, three of which might inhibit rooting and one might promote rooting. Conclusion The increase of antioxidant enzyme activities of cuttings can promote the occurrence of adventitious roots of C. bungei. Soluble sugar and soluble protein are the main nutrients of cuttings. Quercetin, linoleic acid and palmitic acid may inhibit the rooting of cuttings and phytosterol may promote the rooting of cuttings. [Ch, 2 fig. 4 tab. 32 ref.]

The individual and interactive role of arbuscular mycorrhizal fungi and Trichoderma viride on growth, protein content, amino acids fractionation, and phosphatases enzyme activities of onion plants amended with fish waste

The Green Revolution faced a great cost to meet ever-increasing demands for food, where indiscriminate use of agrochemicals resulted in non-friendly habitats. Therefore, the development of a sustainable approach to better crop production of onion seeds (Allium cepa L.) is very crucial. It is time to use organic waste as a replacement for agrochemicals by using arbuscular mycorrhizal fungi (AMF) and Trichoderma. Fish waste as representative of food waste acts as a leading cause of contamination of the environment. The interaction of AMF and Trichoderma viride on biomass, total soluble protein, mycorrhizal colonization, amino acids, phosphatases and phosphorus and nitrogen contents of onion plants grown in fish waste amended soil was studied. Fish waste has caused a slight increase in onions biomass, total free amino acids, and soluble protein content while with AMF and T. viride dual inoculation more increments were recorded; such increases were related to an increase in mycorrhizal colonization. T. viride application significantly increased the mycorrhizal colonization levels, but these were significantly reduced with waste addition. Analysis of amino acids in plants showed that their concentrations had changed as a result of waste addition combined with AMF and/or T. viride. The effectiveness of fish waste combined with low cost and health/environmental safety leads to a prediction that the introduction of fish waste coupled with fungi will become a more popular feature of agriculture in the future.

Effect of solid-state fermentation with Bacillus subtilis lwo on the proteolysis and the antioxidative properties of chickpeas

In this study, the solid-state fermentation (SSF) of chickpeas by using Bacillus subtilis lwo was performed to evaluate the effect of fermentation on the proteolysis and the antioxidative properties of chickpeas. The soluble protein, peptide, and free amino nitrogen contents; proteinase activity; degradation of protein; peptide profiles; and the antioxidant activities during fermentation were investigated. Results indicated that during the fermentation process, increasing the protease activity resulted in increased release of soluble proteins, peptides, and free amino nitrogen (FAN), which reached their maximum values (15.4 mg/g, 25.8 mg/g, and 1.03 g/100 g, respectively) at 48 h of fermentation. The electrophoretic profiles indicated that most chickpea proteins were degraded after fermentation for 24 h. High-performance liquid chromatography (HPLC) indicated a decreased/disappearance of hydrophobic/large peptides and increased hydrophilic/small peptides. Moreover, the fermented chickpeas showed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radical scavenging activities than the unfermented chickpeas. These data suggested that the fermentation process by using B. subtilis lwo improved the proteolysis and the antioxidative activities of chickpeas. Thus, this method may provide a novel way to enhance the value of chickpeas, and the chickpeas fermented by B. subtilis lwo can be used in food industries.

Relationship between chemical fertilization in sorghum and Melanaphis sacchari/sorghi (Hemiptera: Aphididae) populations

The aphid Melanaphis sacchari/sorghi is considered the most important pest of sorghum cultivation in Mexico. It can cause losses in production of up to 100%. This research was conducted at the Universidad Autonoma Chapingo during 2018 and 2019 with the objective of determining the relationship between chemical fertilization in sorghum and M. sacchari/sorghi (Hemiptera: Aphididae) populations. Different levels of nitrogen (125, 250 and 500 kg ha-1), phosphorus (19.5, 39 and 78 kg ha-1) and potassium (210 and 420 kg ha-1) were supplied to sorghum plants planted in polyethylene pots with a capacity of 6 L under greenhouse conditions. The plants were infested with a total of 15 third-instar nymphs within 60 days of crop emergence. A total of 6 samplings were carried out at 7 day intervals, starting at 7 d after the infestation. Quantifications of total soluble proteins, total soluble sugars, reducing sugars, and levels of nitrogen, phosphorus, potassium and magnesium in leaf tissue were also performed. We observed that higher doses of nitrogen and phosphorus increased the aphid population, while increasing the potassium dose considerably decreased the aphid population. We also found a positive correlation between the aphid population and the total soluble protein concentrations, reducing sugars and nitrogen levels, while the correlation was negative with potassium levels in leaves.

Physiological responses and small RNAs changes in maize under nitrogen deficiency and resupply.

Maize is an important crop in the world, nitrogen stress severely reduces maize yield. Although a large number of studies have identified the expression changes of microRNAs (miRNAs) under N stress in several species, the miRNAs expression patterns of N-deficient plants under N resupply remain unclear. The primary objective of this study was to identify miRNAs in response to nitrogen stress and understand relevant physiological changes in nitrogen-deficient maize after nitrogen resupply. Physiological parameters were measured to study relevant physiological changes under different nitrogen conditions. Small RNA sequencing and qRT-PCR analysis were performed to understand the response of miRNAs under different nitrogen conditions. The content of chlorophyll, soluble protein and nitrate nitrogen decreased than CK by 0.52, 0.49 and 0.82 times after N deficiency treatment and increased than ND by 0.52, 1.36 and 0.65 times after N resupply, respectively. Conversely, the activity of superoxide dismutase (SOD) and peroxidase (POD) increased by 0.67 and 1.64 times than CK after N deficiency, respectively, and decreased by 0.09 and 0.35 times than ND after N resupply. A total of 226 known miRNAs were identified by sRNA sequencing; 106 miRNAs were differentially expressed between the control and N-deficient groups, and 103 were differentially expressed between the N-deficient and N-resupply groups (P < 0.05). Real-time quantitative PCR (qPCR) was used to further validate and analyze the expression of the identified miRNAs. A total of 1609 target genes were identified by target prediction, and some differentially expressed miRNAs were predicted to target transcription factors and functional proteins. Gene Ontology (GO) analysis was used to determine the biological function of these targets and revealed that some miRNAs, such as miR169, miR1214, miR2199, miR398, miR408 and miR827 might be involved in nitrogen metabolism regulation. Our study comprehensively provides important information on miRNA functions and molecular mechanisms in response to N stress. These findings may assist to improve nitrogen availability in plants.

Application of high pressure processing to improve digestibility, reduce allergenicity, and avoid protein oxidation in cod (Gadus morhua)

In this study, comprehensive analysis was performed to evaluate the impact of high hydrostatic pressure (HHP) and traditional thermal processing methods (baking and steaming) on cod proteins. Results showed that HHP, but not baking or steaming, was able to increase the content of soluble protein nitrogen (1.42-fold), compared with control. Total peptide contents of HHP-treated samples were also significantly higher than baked and steamed ones. In addition, protein oxidation was greatly increased after baking (1.56-fold) and steaming (1.97-fold), whereas HHP did not exhibit any appreciable effect. Furthermore, the allergenicity of cod was significantly reduced after HHP as reflected by the attenuated IgE and IgG-binding capacities (67–84% relative to control), while baking and steaming resulted in higher allergenicity. This study strongly supports the potential of HHP for reducing allergenicity, avoiding protein oxidation, and improving digestibility of cod and other protein-rich foods susceptible to quality deterioration during thermal processing.

Optimization of yeast autolysis under solid-state fermentation conditions

Yeast autolysis under solid-state fermentation can effectively promote the release of various active substances, thereby improving the quality of yeast products. The optimal process for yeast autolysis under solid-state fermentation was obtained by optimizing the autolysis temperature, autolysis time and the zinc ion concentration. We analyzed the indexes of free amino acid, soluble protein and α-amino nitrogen in the fermentation material, as well as A₂₆₀/A₂₈₀ ratio to determine yeast autolysis process conditions in the solid-state fermentation. On the basis of the obtained data, L₉ (3³) orthogonal test was designed to optimize the solid-state fermentation parameters for yeast autolysis: temperature at 40, 50 and 55 °C; time 12, 18 and 24 h; zinc ion concentration 2, 4 and 8 mg/kg. The optimum process conditions for yeast autolysis were: autolysis temperature 55 °C, time 18 h, zinc ion concentration 2 mg/kg, and soluble protein content reached 9.31 mg/g, free amino acid 14.36 mg/g, α-amino nitrogen 10.16 μg/g and A₂₆₀/A₂₈₀ 1.73. After optimization of the process, the soluble protein, free amino acid and α-amino nitrogen contents of the yeast autolysis production can be significantly increased, thereby obviously improving the quality of the composite culture.

Evaluation of physicochemical characteristics of microwave vacuum dried mackerel and inhibition of oxidation by essential oils.

In the present study, Indian mackerel was dried by microwave vacuum drying (MVD) method and compared its physico chemical quality to mackerel dried by hot air drying (HAD) method. Antioxidant effects of thyme oil (TMO) and clove leaf oils (CLO) during storage were also evaluated. Brine salted mackerel was dried in hot air oven (50-55°C) and microwave vacuum dryer (600W and 600Hgmm). For essential oil treatment, mackerel was dipped in 0.75% TMO and CLO for 5min. Moisture content of MVD and HAD samples was reduced to 30-32% in 1.2h and 12h, respectively. Rehydration ability and water absorption index of MVD samples were significantly higher to that of HAD samples. Mackerel dried by HAD showed significantly higher salt soluble and water soluble protein nitrogen fractions than that of MVD samples. Significantly higher hardness and chewiness values were observed for HAD samples. Color and appearance of uncooked MVD sample was superior to that of HAD samples. As per the results of PV and TBARS, TMO exhibited better antioxidant effect compared to CLO. The study demonstrated that fast drying can be achieved by microwave vacuum dryer and it can produce dried fish having better sensory and textural attributes.

Impacts of soil salinity on Bt protein concentration in square of transgenic Bt cotton.

Insect-resistance of transgenic Bacillus thuringiensis (Bt) cotton varies among plants organs and with different environmental conditions. The objective of this study was to examine the influence of soil salinity on Bt protein concentration in cotton squares and to elucidate the potential mechanism of Bt efficacy reduction. Two cotton cultivars (NuCOTN 33B and CCRI 07, salt-sensitive and salt-tolerant) were subjected to salinity stress under four natural saline levels in field conditions in 2015 and 2016 and seven regimes of soil salinity ranged from 0.5 to 18.8 dS m-1 in greenhouse conditions in 2017. Results of field studies revealed that Bt protein content was not significantly changed at 7.13 dS m-1 salinity, but exhibited a significant drop at the 10.41 and 14.16 dS m-1 salinity. The greenhouse experiments further showed similar trends that significant declines of the insecticidal protein contents in squares were detected when soil salinity exceeded 9.1 dS m-1. Meanwhile, high salinity resulted in significant reduction in contents of soluble protein and total nitrogen, activities of nitrate reductase (NR), glutamine synthetase (GS) and glutamic-pyruvic transaminase (GPT), but increased amino acid content, activities of protease and peptidase in cotton squares. High salinity also decreased root vigor (RV), root total absorption area (RTA) and root active absorption area (RAA). The extent of decrease of Bt protein content was more pronounced in NuCOTN 33B than CCRI 07, and CCRI07 exhibited stronger enzymes activities involved in square protein synthesis and higher levels of RV, RTA and RAA. Therefore, the results of our present study indicated that insecticidal protein expression in cotton squares were significantly affected by higher salinity (equal to or higher than 9.1 dS m-1), reduced protein synthesis and increased protein degradation in squares and reduced metabolic activities in roots might lead to the decrease of Bt protein content in squares.

Effect of level of oat hay intake on apparent digestibility, rumen fermentation and urinary purine derivatives in Tibetan and fine-wool sheep

Tibetan sheep are indigenous to the Qinghai-Tibetan Plateau and are raised at an altitude between 3000–5000 m. In contrast, the crossbred fine-wool sheep were introduced to the plateau and are raised at an altitude between 2600 to 3500 m. Tibetan sheep graze grassland all year round while fine-wool sheep require feed supplements during the long cold season. Tibetan sheep were able to utilize dietary nutrients more efficiently than fine-wool sheep when offered adequate energy and protein diets. We questioned whether the responses would still favour Tibetan sheep with limited energy and protein intakes, as is often the case on the Qinghai-Tibetan Plateau. To answer this query, apparent nutrients digestibilities, rumen fermentation characteristics and urinary purine derivatives (PD) were compared between Tibetan and fine-wool sheep when fed oat hay at below maintenance levels: 0.3, 0.5, 0.7 and 0.9 voluntary intake. Five wethers of each breed of similar age and body weight (BW) were used in two concurrent 4 × 4 Latin square designs. Dry matter (DM), organic matter (OM) and neutral detergent fiber (NDF) digestibilities were higher in Tibetan than fine-wool sheep (P < 0.05), but were not affected by the level of oat hay intake (P > 0.10). As feed intake increased, ruminal pH decreased (P < 0.01) and total volatile fatty acid (VFA) concentration increased, both linearly (P < 0.001). Moreover, ruminal total VFA concentration (P < 0.05), ruminal soluble protein nitrogen (N) and saliva urea-N concentrations (P < 0.01) were higher in Tibetan than fine-wool sheep. Urinary total PD and its fractions increased linearly with feeding level (P < 0.01). Estimated microbial N synthesis was greater in Tibetan than fine-wool sheep (P < 0.05) and increased linearly with the level of oat hay intake (P < 0.001). It was concluded that both energy and protein metabolism were used more efficiently in Tibetan than in fine-wool sheep when offered below maintenance intakes, which would allow Tibetan sheep to cope better with the harsh, winter foraging conditions of the Qinghai-Tibetan Plateau.

Pretreatment of waste activated sludge by peracetic acid oxidation for enhanced anaerobic digestion

This article studied the sludge reduction and supernatant changes during peracetic acid (PAA) oxidation and investigated subsequent anaerobic biodegradation. PAA oxidation treatment effectively leads to a disintegration of sewage sludge. The results suggested that the sludge solid concentration and volatile solid concentration decreased by 24.5 and 39.0% after 120 min, respectively, when the PAA dose was 30 mg PAA/g SS. The VSS to SS ratio dropped from 0.85 to 0.71. The concentration of supernatant soluble chemical oxygen demand, protein, total phosphorus, polysaccharide, and ammonia nitrogen increased by 530, 177, 166, 165, and 222%, respectively. Biogas production was enhanced when PAA was employed as a pretreatment. Compared with the control system, the cumulative biogas production increased by 20.0% after 28 days of anaerobic digestion (AD). The biogas production rate in digester with pretreated sludge reached the maximum on day 8 at 87mL/d, but the peak value was obtained on day 11 at 74mL/d in digester with the raw sludge, which indicated that PAA pretreatment could decrease the retention time of AD and increase biogas yield. © 2018 American Institute of Chemical Engineers Environ Prog, 37: 1901–1907, 2018