Timosaponin AⅢ induces drug-metabolizing enzymes by activating constitutive androstane receptor (CAR) via dephosphorylation of the EGFR signaling pathway

The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administration of T-AⅢ,the nude mice exhibited an induction of CYP2B10,MDR1,and CYP3A11 expression in the liver tissues.In the ICR mice,the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration.The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6,MDR1,and CYP3A4,along with constitutive androstane receptor(CAR)activation.Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression.Furthermore,other CAR target genes also showed a significant increase in the expression.The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice.Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation,with this effect being partially reversed by the ERK activator t-BHQ.Inhibition of the ERK1/2 signaling pathway was also observed in vivo.Additionally,T-AⅢ inhibited the phosphorylation of EGFR at Tyr1173 and Tyr845,and suppressed EGF-induced phosphorylation of EGFR,ERK,and CAR.In the nude mice,T-AⅢ also inhibited EGFR phosphorylation.These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway.

Engineering high amylose and resistant starch in maize by CRISPR/Cas9-mediated editing of starch branching enzymes

To improve the amylose content(AC)and resistant starch content(RSC)of maize kernel starch,we employed the CRISPR/Cas9 system to create mutants of starch branching enzyme I(SBEI)and starch branching enzyme IIb(SBEIIb).A frameshift mutation in SBEI(E1,a nucleotide insertion in exon 6)led to plants with higher RSC(1.07%),lower hundred-kernel weight(HKW,24.71±0.14 g),and lower plant height(PH,218.50±9.42 cm)compared to the wild type(WT).Like the WT,E1 kernel starch had irregular,polygonal shapes with sharp edges.A frameshift mutation in SBEIIb(E2,a four-nucleotide deletion in exon 8)led to higher AC(53.48%)and higher RSC(26.93%)than that for the WT.E2 kernel starch was significantly different from the WT regarding granule morphology,chain length distribution pattern,X-ray diffraction pattern,and thermal characteristics;the starch granules were more irregular in shape and comprised typical B-type crystals.Mutating SBEI and SBEIIb(E12)had a synergistic effect on RSC,HKW,PH,starch properties,and starch biosynthesis-associated gene expression.SBEIIa,SS1,SSIIa,SSIIIa,and SSIIIb were upregulated in E12 endosperm compared to WT endosperm.This study lays the foundation for rapidly improving the starch properties of elite maize lines.

The Effect of Soil Enzymes and Polysaccharides Secreted by the Roots of Salvia miltiorrhiza Bunge under Drought,High Temperature,and Nitrogen and Phosphorus Deficits

Root exudates serve as crucial mediators for information exchange between plants and soil,and are an important evolutionary mechanism for plants’adaptation to environmental changes.In this study,15 different abiotic stress models were established using various stress factors,including drought(D),high temperature(T),nitrogen deficiency(N),phosphorus deficiency(P),and their combinations.We investigated their effects on the seedling growth of Salvia miltiorrhiza Bunge and the activities of Solid-Urease(S-UE),Solid-Nitrite Reductase(S-NiR),Solid-Nitrate Reductase(S-NR),Solid-Phosphotransferase(S-PT),and Solid-Catalase(S-CAT),as well as the contents of polysaccharides in the culture medium.The results showed that the growth of S.miltiorrhiza was inhibited under 15 stress conditions.Among them,13 stress conditions increased the root-shoot ratio.These 15 stress conditions significantly reduced the activity of S-NR,two combinations significantly improved the activity of S-NIR,they were synergistic stresses of high temperature and nitrogen deficiency(TN),and synergistic stresses of drought and nitrogen deficiency(DN)(p<0.05).The activity of S-UE was significantly improved under N,D,T,synergistic stresses of drought and high temperature(DT),DN,synergistic stresses of drought and phosphorus deficiency(DP),and synergistic stresses of high temperature,nitrogen,and phosphorus deficiency(TNP)stress conditions(p<0.05).Most stress combinations reduced the activity of S-PT,but D and T significantly improved it.(p<0.05).The N,DN,and TN stress conditions significantly reduced S-CAT activity.The P,DT,and synergistic stresses of drought,high temperature,and phosphorus deficiency(DTP)significantly decreased the total polysaccharide content of the soil(p<0.05).The research suggested that abiotic stress hindered the growth of S.miltiorrhiza and altered the behavior of root secretion.Roots regulated the secretion of several substances in response to various abiotic stresses,including soil nitrogen cycle enzymes,phosphorus transport-related enzymes,and antioxidant enzymes.In conclusion,plants regulate the utilization of rhizosphere substances in response to abiotic stresses by modulating the exudation of soil enzymes and polysaccharides by the root system.At the same time,soil carbon sequestration was affected by the adverse environment,which restricted the input of organic matter into the soil.

Screening for metabolic dysfunction-associated fatty liver disease:Time to discard the emperor’s clothes of normal liver enzymes?

Metabolic dysfunction-associated fatty liver disease(MAFLD)is the most prevalent chronic liver condition worldwide.Current liver enzyme-based screening methods have limitations that may missed diagnoses and treatment delays.Regarding Chen et al,the risk of developing MAFLD remains elevated even when alanine aminotransferase levels fall within the normal range.Therefore,there is an urgent need for advanced diagnostic techniques and updated algorithms to enhance the accuracy of MAFLD diagnosis and enable early intervention.This paper proposes two potential screening methods for identifying individuals who may be at risk of developing MAFLD:Lowering these thresholds and promoting the use of noninvasive liver fibrosis scores.

Expression level of myocardial enzymes in patients with schizophrenia: Predictive value in the occurrence of violence

BACKGROUND Schizophrenic patients are prone to violence,frequent recurrence,and difficult to predict.Emotional and behavioral abnormalities during the onset of the disease,resulting in active myocardial enzyme spectrum.AIM To explored the expression level of myocardial enzymes in patients with schizo-phrenia and its predictive value in the occurrence of violence.METHODS A total of 288 patients with schizophrenia in our hospital from February 2023 to January 2024 were selected as the research object,and 100 healthy people were selected as the control group.Participants’information,clinical data,and labo-ratory examination data were collected.According to Modified Overt Aggression Scale score,patients were further divided into the violent(123 cases)and non-violent group(165 cases).RESULTS The comparative analysis revealed significant differences in serum myocardial enzyme levels between patients with schizophrenia and healthy individuals.In the schizophrenia group,the violent and non-violent groups also exhibited different levels of serum myocardial enzymes.The levels of myocardial enzymes in the non-violent group were lower than those in the violent group,and the patients in the latter also displayed aggressive behavior in the past.CONCLUSION Previous aggressive behavior and the level of myocardial enzymes are of great significance for the diagnosis and prognosis analysis of violent behavior in patients with schizophrenia.By detecting changes in these indicators,we can gain a more comprehensive understanding of a patient’s condition and treatment.

Plant-Derived Enzymes Producing Chiral Aroma Compounds and Potential Application

Aroma(volatile)compounds play important ecological functions in plants,and also contribute to the quality of plant-derived foods.Moreover,chiral aroma compounds affect their functions in plants and lead to different flavor quality properties.Formations of chiral aroma compounds are due to the presence of enzymes producing these compounds in plants,which are generally involved in the final biosynthetic step of the aroma compounds.Here,we review recent progress in research on the plant-derived enzymes producing chiral aroma compounds,and their changes in response to environmental factors.The chiral aroma enzymes that have been reported produce(R)-linalool,(S)-linalool,(R)-limonene,and(S)-limonene,etc.,and these enzymes are found in various plant species.We also discuss the origins of enantioselectivity in the plant-derived enzymes producing chiral aroma compounds and summarize the potential use of plants containing enzymes producing chiral aroma compounds for producing chiral flavors/fragrances.

Changes in the activities of key enzymes and the abundance of functional genes involved in nitrogen transformation in rice rhizosphere soil under different aerated conditions

Soil microorganisms play important roles in nitrogen transformation. The aim of this study was to characterize changes in the activity of nitrogen transformation enzymes and the abundance of nitrogen function genes in rhizosphere soil aerated using three different methods(continuous flooding(CF), continuous flooding and aeration(CFA), and alternate wetting and drying(AWD)). The abundances of amoA ammonia-oxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB), nirS, nirK, and nifH genes, and the activities of urease, protease, ammonia oxidase, nitrate reductase, and nitrite reductase were measured at the tillering(S1), heading(S2), and ripening(S3) stages. We analyzed the relationships of the aforementioned microbial activity indices, in addition to soil microbial biomass carbon(MBC) and soil microbial biomass nitrogen(MBN), with the concentration of soil nitrate and ammonium nitrogen. The abundance of nitrogen function genes and the activities of nitrogen invertase in rice rhizosphere soil were higher at S2 compared with S1 and S3 in all treatments. AWD and CFA increased the abundance of amoA and nifH genes, and the activities of urease, protease, and ammonia oxidase, and decreased the abundance of nirS and nirK genes and the activities of nitrate reductase and nitrite reductase, with the effect of AWD being particularly strong. During the entire growth period, the mean abundances of the AOA amoA, AOB amoA, and nifH genes were 2.9, 5.8, and 3.0 higher in the AWD treatment than in the CF treatment, respectively, and the activities of urease, protease, and ammonia oxidase were 1.1, 0.5, and 0.7 higher in the AWD treatment than in the CF treatment, respectively. The abundances of the nirS and nirK genes, and the activities of nitrate reductase and nitrite reductase were 73.6, 84.8, 10.3 and 36.5% lower in the AWD treatment than in the CF treatment, respectively. The abundances of the AOA amoA, AOB amoA, and nifH genes were significantly and positively correlated with the activities of urease, protease, and ammonia oxidase, and the abundances of the nirS and nirK genes were significantly positively correlated with the activities of nitrate reductase. All the above indicators were positively correlated with soil MBC and MBN. In sum, microbial activity related to nitrogen transformation in rice rhizosphere soil was highest at S2. Aeration can effectively increase the activity of most nitrogen-converting microorganisms and MBN, and thus promote soil nitrogen transformation.

Fat,oil,and grease as new feedstock towards bioelectrogenesis in microbial fuel cells:Microbial diversity,metabolic pathways,and key enzymes

Microbial fuel cells(MFCs)are a well-known technology used for bioelectricity production from the decomposition of organic waste via electroactive microbes.Fat,oil,and grease(FOG)as a new substrate in the anode and microalgae in the cathode were added to accelerate the electrogenesis.The effect of FOG concentrations(0.1%,0.5%,1%,and 1.5%)on the anode chamber was investigated.The FOG degradation,volatile fatty acid(VFAs)production,and soluble chemical oxygen demand along with voltage output kinetics were analyzed.Moreover,the microbial community analysis and active functional enzymes were also evaluated.The maximum power and current density were observed at 0.5%FOG which accounts for 96 mW m^(-2)(8-folds enhancement)and 560 mA m^(-2)(3.7-folds enhancement),respectively.The daily voltage output enhanced upto 2.3-folds with 77.08%coulombic efficiency under 0.5%FOG,which was the highest among all the reactors.The 0.5%FOG was degraded>85%,followed by a 1%FOG-loaded reactor.The chief enzymes inβ-oxidation and electrogenesis were acetyl-CoA C-acetyltransferase,riboflavin synthase,and riboflavin kinase.The identified enzymes symbolize the presence of Clostridium sp.(>15%)and Pseudomonas(>10%)which served as electrochemical active bacteria(EAB).The major metabolic pathways involved in electrogenesis and FOG degradation were fatty acid biosynthesis and glycerophospholipid metabolism.Utilization of lipidic-waste(such as FOG)in MFCs could be a potential approach for simultaneous biowaste utilization and bioenergy generation.

Toxicity of Tagetes erecta Essential Oil Based Combinatorial Formulations on Various Metabolic Enzymes in Indian White Termite Odontotermes obesus

Plant essential oils and their constituents have proven to be very effective against insects, especially termites. They are the best alternative to synthetic pesticides that are harmless to the environment and human health. In the present study, different enzymes, namely alkaline phosphatase, acid phosphatase, glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase and acetylcholinesterase, were evaluated in Indian termite Odontotermes obesus in a combination preparation based on Tagetes erecta essential oil. For the study of anti-termite effects against worker termites were treated topically with 40% and 80% of the 24-hour LD50 values of various combination formulations. Subsequent bioassays at 40% and 80% of LD50 of combinatorial preparations S-AST-A, S-AST-B, and S-AST-C resulted in a significant (p > 0.05) decrease in glutamate-oxaloacetate transaminase. After 16 hours of treatment, they were 87.92%, 80.17%, 89.30%, 79.17%, 81.92% and 73.17% respectively. In vivo exposures of 40% and 80% of the LD50 of the combination formulation caused a highly significant (p > 0.05) reduction (p > 0.05) of all test enzymes tested compared to controls. The effects of different oil formulations exhibited time- and dose-dependent responses, resulting in physiological changes in the concentrations of various enzymes. The combined mixture of Tagetes erecta essential oils has significantly better anti-termite ability compared to inorganic insecticides. Findings from this study will help support termite control in fields, gardens and homes in a sustainable way, without the downsides of insecticide resistance and pollution. These could potentially be used to produce commercial formulations for use against pests.

Toxic Effects of Citrus maxima Based Combinatorial Formulations on Important Metabolic Enzymes in Indian White Termite Odontotermes obesus

In the present study, Citrus maxima essential crude oil extract was used to prepare combinatorial formulations and workers of Indian white termite Odontotermes obesus were treated topically with 40% and 80% of 24 hr LD50 values of these formulations. In subsequent bioassays levels of various enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase and acetylcholinesterase were evaluated to determine the anti-termite efficacy of Citrus maxima essential oil based combinatorial formulations. S-RET-A, S-RET-B and S-RET-C caused significant (p > 0.05) decrease in glutamate oxaloacetate transaminase i.e. 87.47%, 86.81% and 81.77% & 82.04%, 79.39% and 74.75% respectively at 16 h treatment. In vivo exposure of 40% and 80% of LD50 of combinatorial formulations caused very significant (p > 0.05) reduction in all the test enzymes i.e. alkaline phosphatase, acid phosphatase, glutamate oxaloacetate transaminase and glutamate pyruvate transaminase expect acetylcholinesterase levels after 16 h all tested treatments in comparison to control. Both dose-response and time period were found important in physiological alteration in levels of various enzymes. Combinatorial mixtures of Citrus essential oils have shown synergistic activity against termites. The research findings of the present study would help termite control in crop fields, gardens and houses in a sustainable way.

Effect of Cellulose Enzymes on Some Properties of Fibre Clothes

This study examined the effects of the enzyme cellulose on a few single jersey and interlock 100% flax t-shirts, two different styles of knit children’s clothes that differ in both their chemical and mechanical characteristics. Clothing samples were dyed using reactive colours and then subjected to normal acid cellulose enzyme treatment procedures. We evaluated some physical and mechanical features before and after cellulose treatments, then compared these characteristics. Its cellulose enzymatic processing enhances some mechanical properties of fibre knitwear, such as pilling resistance and retention of water. Some characteristics of fibre-knitted clothing, such as fabric weight, fabric thickness, fabric burst resistance, and seam tensile strength of T-shirt side seams, are reduced by cellulose enzyme treatment at a manageable rate. Compared to single-jersey all-fiber children’s T-shirts, interlocking 100% flax children’s T-shirts have a better effect of the enzyme cellulose treatment on the majority of physical and mechanical attributes.

Enhanced production of cytidine 5'-monophosphate using biocatalysis of di-enzymes immobilized on amino-functionalized sepharose

Cytidine 5'-monophosphate(5'-CMP)is an essential nucleotide for additives.In this study,enhanced production of 5'-CMP was realized by the transformation of cytidine using co-immobilized di-enzymes,uridine-cytidine kinase(UCK)and acetate kinase(AcK).The immobilization yield of the enzyme had a clear correlation with the surface charges as zeta potential(ξ).Among them,ε-polylysinefunctionalized sepharose(SA-EPL,ξ=9.31 m V)showed high immobilization yield(78.8%),which was4.9-fold than that of nitrilotriacetic acid functionalized sepharose(SA-NTA,ξ=-12.6 m V).The residual activity of affinity co-immobilized enzyme(EPL-Ni/EPL@Ac K-UCK)was higher than 70.6%after recycled 10 times.Thus,this study provides an effective approach for the production of 5'-CMP with the advantages of low adenosine 5'-triphosphate(ATP)consumption,reduced side reactions,and improved reusability by co-immobilized UCK and Ac K on the functionalized Sepharose.

Peptide self‐assembly as a strategy for facile immobilization of redox enzymes on carbon electrodes

Redox-enzyme‐mediated electrochemical processes such as hydrogen production,nitrogen fixation,and CO_(2) reduction are at the forefront of the green chemistry revolution.To scale up,the inefficient two‐dimensional(2D)immobilization of redox enzymes on working electrodes must be replaced by an efficient dense 3D system.Fabrication of 3D electrodes was demonstrated by embedding enzymes in polymer matrices.However,several requirements,such as simple immobilization,prolonged stability,and resistance to enzyme leakage,still need to be addressed.The study presented here aims to overcome these gaps by immobilizing enzymes in a supramolecular hydrogel formed by the self‐assembly of the peptide hydrogelator fluorenylmethyloxycarbonyldiphenylalanine.Harnessing the self‐assembly process avoids the need for tedious and potentially harmful chemistry,allowing the rapid loading of enzymes on a 3D electrode under mild conditions.Using the[FeFe]hydrogenase enzyme,high enzyme loads,prolonged resistance against electrophoresis,and highly efficient hydrogen production are demonstrated.Further,this enzyme retention is shown to arise from its interaction with the peptide nanofibrils.Finally,this method is successfully used to retain other redox enzymes,paving the way for a variety of enzyme‐mediated electrochemical applications.

Effects of Different Nitrogen and Phosphorus Synergistic Fertilizer on Enzymes and Genes Related to Nitrogen Metabolism in Wheat

In recent years,in order to improve nutrient use efficiency,especially nitrogen use efficiency,fertilizer valueadded technology has been developed rapidly.However,the mechanism of the effect of synergistic fertilizer on plant nitrogen utilization is not clear.A study was,therefore,conducted to explore the activities and gene expression of key enzymes for nitrogen assimilation and the gene expression of nitrogen transporters in wheat after the application of synergistic fertilizer.Soil column experiment was set up in Qingdao Agricultural University experimental base from October 2018 to June 2019.Maleic acid and itaconic acid were copolymerized with acrylic acid as cross-linking monomer to make a fluid gel,which was sprayed on the fertilizer surface to make nitrogen and phosphorus synergistic fertilizer.A total of 6 treatments was set according to different nitrogen and phosphorus fertilizer ratios:(1)100%common nitrogen fertilizer+100%common phosphate fertilizer(2)70%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(3)100%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(4)100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(5)70%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(6)100%commercial nitrogen synergistic fertilizer+100%commercial phosphorus synergistic fertilizer.The results are as follows:(1)the enzyme activities of wheat plants under synergistic fertilizer condition were higher than those under ordinary fertilizer,except under the treatment that nitrogen and phosphorus synergistic fertilizer were both reduced;(2)the expression level of the genes under the treatment“100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer”was significantly higher than those in other treatments.Combined with the higher performance of nitrogen concentration in various parts of the plant under the condition of applying synergistic fertilizer,this study indicated that the application of synergistic fertilizer can improve the nitrogen metabolism of the plant by increasing the nitrogen level in the rhizosphere soil,inducing the expression of nitrogen transporter genes and key assimilation enzymes genes.

Investigation and Benefits of the Use of Enzymes for Unbleached Kraft Recycling Wet Strength Paper at Lab and Industrial Scale

The deterioration of recycled fibers especially unbleached kraft with high wet strength resin content due to the irreversible structural changes caused by drying and added chemicals makes the raw material difficult to repulp.The mechanical effect in the pulper over time with chemical treatment has a negative impact on the recycled fibers.At lab scale,different compositions of enzymatic treatment C022L were under investigation to select the most efficient laccase Lacc1,Lacc2 or Lacc3 and to observe the impact of lipases during repulping at low and high consistencies.Pulp disintegration at different times was evaluated to define the level of rejects and to analyze the morphology of fibers after treatments.These results were more significant for Lacc2,by increasing the pulp consistency to 15%in the pulper.Combining lipases with CELODASE 022L appeared to decrease the efficiency of enzymes.The results showed a high reduction of energy power with the enzymatic treatment and a significant reduction of fines level in fibers’suspension.The most efficient version of C022L was used at industrial scale to compare directly with the standard conditions used in a paper mill.

不同品种鲜食糯玉米采后贮藏品质及抗氧化酶活性的变化

为探究不同品种鲜食糯玉米采后贮藏品质及抗氧化酶活性变化规律,选用京科糯2000、京科糯768以及农科糯336为材料,研究其在20℃常温贮藏条件下感官品质、硬度、失重率、色泽、V_(C)、可溶性固形物、糖类物质、丙二醛含量和抗氧化酶活性的变化规律。结果表明,随着贮藏天数的延长,不同品种鲜食糯玉米均出现不同程度地籽粒失水皱缩、风味散失、光泽和甜度下降等现象,京科糯768表面劣变最为严重,其次是农科糯336,京科糯2000籽粒表面劣变程度最轻。三个品种鲜食糯玉米的硬度、L*值、V_(C)、可溶性固形物、可溶性糖含量均下降,失重率、b*值、淀粉和丙二醛含量总体升高。农科糯336中V_(C)、可溶性固形物和可溶性糖含量下降幅度最小,且淀粉和丙二醛含量上升幅度最小,并且可溶性糖含量和过氧化物酶(Peroxidase,POD)活性显著高于京科糯2000与京科糯768(P<0.05),而抗坏血酸过氧化物酶(Ascorbate peroxidase,APX)活性显著高于京科糯768(P<0.05)。综上,农科糯336在贮藏期间具有更好的营养价值和贮藏品质,并且还具有较高的POD活性。京科糯2000在贮藏期间,果实内部葡萄糖、果糖以及L*值的下降幅度和b*值上升幅度均最小,感官品质较好。而京科糯768能更好地维持玉米籽粒硬度值。

酶催化固碳过程及其强化技术研究进展

全球范围迅猛发展的工业生产导致温室气体CO_(2)的排放,引发人们对全球气候变化的普遍关切。在发展清洁能源、工业流程再造等减少碳排放的同时,开发高效、经济的CO_(2)捕集、利用与储存(CCUS)技术显得尤为迫切。本文基于CO_(2)资源化利用的目的,对生物体外酶催化固碳过程及其强化技术的研究进展进行综述。首先,介绍了CO_(2)转化过程中涉及的关键催化酶及其优化,阐述了CO_(2)资源化利用的具体策略,涵盖了将CO_(2)催化转化为甲酸、甲醇、甲烷、淀粉以及L-乳酸、丙酮酸等特定产物分子。进而,重点阐述了辅因子的原位再生、酶的固定化、反应系统的优化设计、反应条件优化(pH、温度、底物浓度)以及产物原位分离等技术对CO_(2)生物酶催化反应过程的强化,实现CO_(2)的高效固定与资源化利用。旨在通过多方面交叉论述,为生物酶催化过程及路线设计包括固定化酶催化剂的制备、反应器选择设计与开发、酶催化过程调控、高值化产品定向合成等提供有益的启发和思考。最后,总结了酶催化固碳过程存在的问题和挑战,并对其未来值得研究的方向进行了展望。

免疫亲和层析技术协同酶联免疫吸附法检测赭曲霉毒素A

利用免疫亲和层析技术(immunoaffinity chromatography,IAC)对样品中赭曲霉毒素A(ochratoxin A,OTA)进行捕获与浓缩,利用酶联免疫吸附(enzyme-linked immunosorbent assay,ELISA)法对IAC捕获的目标物OTA进行测定。IAC与ELISA中的抗OTA单克隆抗体来自不同的克隆株,分属不同独特型,与OTA结合靶点的选择性存在差异,IAC与ELISA协同检测,可以有效过滤OTA结构类似物造成的干扰,提高免疫分析的特异性与灵敏度。该方法用于加标样品测定时,OTA的检出限为0.2 ng/g,定量限为0.4 ng/g,OTA的平均回收率为75.9%,与单一的ELISA法相比,该方法虽然回收率略低,但灵敏度可以显著提高,达到ELISA法的60倍。通过对49份样品的实际检测,该方法检出阳性样品与国标法的符合率达到100%,漏检率为0%,由此可见,该方法在准确性上表现出明显的优势。作为一种综合免疫分析技术,该方法不需要大型仪器设备,对操作环境没有严格要求,便于基层实验室对样品中OTA的分析。

壳聚糖处理对节瓜室温贮藏品质及酶活性的影响

以节瓜为试材,采用不同浓度(0.5%、1.0%和1.5%)壳聚糖涂膜处理节瓜3 min,以不作任何处理为对照,每隔15 d测定节瓜室温贮藏期间感官评价、失重率、维生素C、可溶性固形物、可溶性糖、可溶性蛋白质、丙二醛含量及过氧化氢酶(CAT)、过氧化物酶(POD)和多酚氧化酶(PPO)活性的变化,研究了壳聚糖处理对节瓜室温贮藏期间品质及酶活性的影响,以期为节瓜室温贮藏提供参考依据。结果表明:与对照相比,不同浓度壳聚糖处理均能延缓节瓜品质的下降。其中,1.0%壳聚糖处理能显著减少失重率,抑制维生素C、可溶性固形物、可溶性糖及可溶性蛋白质下降,显著降低丙二醛(MDA)含量和PPO活性,提高POD、CAT活性。综上,壳聚糖处理能维持节瓜室温贮藏期间品质,延长节瓜室温贮藏时间,以1.0%壳聚糖处理效果最佳。

不同添加剂处理对水稻秸秆营养成分及发酵品质的影响

试验研究不同添加剂处理对水稻秸秆营养成分及发酵品质的影响,旨在提高水稻秸秆的利用率。试验以水稻秸秆为青贮原料,各试验组分别添加1.0 g/kg酶制剂、2.0 g/kg菌制剂及1.0 g/kg酶制剂+2.0 g/kg菌制剂,对照组不添加添加剂,每组设置4个重复。青贮60 d后,取样检测各组水稻秸秆青贮的感官指标、营养成分、发酵品质及瘤胃营养物质降解率。结果表明,对照组水稻秸秆青贮感官总分为13分,为2级尚好,而酶制剂、菌制剂及菌酶制剂处理的水稻秸秆青贮感官评定均较好,达到1级优良。与对照组比较,试验2组和试验3组的水稻秸秆青贮的干物质和总可消化养分含量升高(P<0.05),试验3组水稻秸秆青贮的粗脂肪含量升高(P<0.05),酸性洗涤纤维含量降低(P<0.05);试验1组、试验2组和试验3组水稻秸秆青贮的中性洗涤纤维含量降低(P<0.05),可溶性碳水化合物含量升高(P<0.05),相对饲喂价值增加(P<0.05)。与对照组比较,试验2组和试验3组水稻秸秆青贮的乙酸和总挥发性脂肪酸浓度升高(P<0.05),试验1组、试验2组和试验3组水稻秸秆青贮的pH值降低(P<0.05),试验3组水稻秸秆青贮的氨态氮浓度降低(P<0.05)。与对照组比较,试验1组、试验2组和试验3组水稻秸秆青贮的粗蛋白、中性洗涤纤维及干物质的降解率均得到提高(P<0.05)。研究表明,水稻秸秆经酶制剂、菌制剂、菌酶复合处理后,可以改善青贮饲料的感官评价,增加水稻秸秆青贮的营养成分含量,提高瘤胃营养物质的降解率,菌酶复合处理的效果优于酶制剂和菌制剂处理。