Enzyme Activities
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2021 ◽  
Author(s):  
Lisha Song Song ◽  
Limei Pan Pan ◽  
Ni Jiang Jiang ◽  
Jine FU FU ◽  
Lingyun Wan Wan ◽  
...  

Abstract Taxillus chinensis is an extensively used medicinal herb in the traditional as well as modern systems of medicines. It is a perennial hemiparasitic plant, which is difficult to propagate artificially because of its low parasitic rate. Successful parasitism of parasitic plants is to fuse their tissues and connect their vasculature to the host vasculature building a physiological bridge, which can efficiently withdraw water, sugars and nutrients from their host plants. It is reported that endophytic fungi play an important role in cell wall degradation and fusion, which is the key forming process of the physiological bridge. Therefore, in this study, the endophytic fungi from T. chinensis of different hosts were isolated, and then the organisms that could degrade the main components of the cell walls were screened out using a medium consisting of guaihuol and cellulose degradation capacity. The results showed that five strains with high enzyme activities for lignocellulosic degradation were screened out from 72 endophytic fungi of T. chinensis. The laccase and cellulase activities of five strains reached their peaks at day 7, and the highest enzyme activities of these two enzymes were found in strain P6, which was 117.66 and 1.66 U/mL, respectively. Manganese peroxidase of strain 4 and lignin peroxidase of strain N6 also reached their peaks at day 7 and were the highest among the 5 strains, with enzyme activities of 11.61 and 6.64 U/mL, respectively. Strains 4, 15, 31, N6 and P6 were identified as Colletotrichum acutatum, Nigerrospora sphaerica, Exserohilum rofolium, Diaporthe phaseolorum and Pestalotiopsis arceuthobii, respectively, according to their morphological and molecular biology properties.


Author(s):  
Anam Sahreen ◽  
Kaneez Fatima ◽  
Tahmina Zainab ◽  
Mohammad Khalid Saifullah

Abstract Background Helminth infection and infestation in fishes are detrimental and have a major effect on fish health and fish production. Among various factors, parasitic infections are known to modulate antioxidant defences in fish. Similar to other aerobic animals, fish are also susceptible to the effect of reactive oxygen species and thus have well established intrinsic and efficient antioxidant defences. ‘Oxidative stress markers are an important indicator of the physiological state of the parasite and its host’. Indian catfish, Wallago attu is a freshwater fish that serves as the definitive host of the adult piscine trematode Isoparorchis hypselobagri. Our two years prevalence data signifies the intensity of the problem revealing a minimum of 5.5% and a maximum of 54% I. hypselobagri infection in Indian catfish W. attu (unpublished data). The present study aimed to achieve baseline data attributed to changes in some oxidative markers due to parasitic infection. Results During the present study, the level of enzyme activities of Catalase (CAT), Glutathione reductase (GR), Glutathione-S-transferase (GST), Glutathione peroxidase (GPx), Superoxide dismutase (SOD) and lipid peroxidation was investigated to explore the pathogenic impact on the fish host. The level of these oxidative stress markers was monitored in the swim bladder, liver, intestine and muscle of the host. We also recorded the enzyme activities in the parasite I. hypselobagri. Analysis of data revealed an elevation in GST, SOD, GR, GPx and CAT activity in the infected host tissue as compared to the non-infected fish. Further, we observed presence of GST, SOD, GR and GPx enzymes in the parasite I. hypselobagri while CAT did not show any enzyme activity. Conclusions Increased level of enzyme activity in liver, muscle and intestine of infected host has been recorded which indicates increased oxidative stress in the host due to parasitic invasion. The presence of antioxidant enzymes in the parasites suggests an active antioxidant defence system to avoid immune responses to long term survival and establishment in their host.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Léo Bürgy ◽  
Simona Eicke ◽  
Christophe Kopp ◽  
Camilla Jenny ◽  
Kuan Jen Lu ◽  
...  

AbstractLiving cells orchestrate enzyme activities to produce myriads of biopolymers but cell-biological understanding of such processes is scarce. Starch, a plant biopolymer forming discrete, semi-crystalline granules within plastids, plays a central role in glucose storage, which is fundamental to life. Combining complementary imaging techniques and Arabidopsis genetics we reveal that, in chloroplasts, multiple starch granules initiate in stromal pockets between thylakoid membranes. These initials coalesce, then grow anisotropically to form lenticular granules. The major starch polymer, amylopectin, is synthesized at the granule surface, while the minor amylose component is deposited internally. The non-enzymatic domain of STARCH SYNTHASE 4, which controls the protein’s localization, is required for anisotropic growth. These results present us with a conceptual framework for understanding the biosynthesis of this key nutrient.


Author(s):  
Nathalie Cheviron ◽  
Virginie Grondin ◽  
Christelle Marrauld ◽  
Françoise Poiroux ◽  
Isabelle Bertrand ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Tong Jia ◽  
Xuerong Wang ◽  
Tingyan Guo ◽  
Baofeng Chai

Microorganisms drive litter decomposition while maintaining the chemical cycle of ecosystems. We used the dominant vegetation (Imperata cylindrica) in the mining area selected for this study for this experiment to explore fungal community characteristics, key fungal groups, and their associative driving factors during I. cylindrica litter decomposition. Maximum litter C/N values occurred 100days after the commencement of the decomposition experiment during all different recovery years in this copper tailings area. Heavy metals in litter [copper (Cu), zinc (Zn), plumbum (Pb), and cadmium (Cd)] accumulated gradually with decomposition. The dominant fungal phyla observed in the community were Ascomycota and Basidiomycota, while the classes Sordariomycetes and Eurotiomycetes significantly increased as litter decomposition progressed. Degrees of connectivity and interaction between fungal communities were highest during the early litter decomposition stage. Sordariomycetes, Dothideomycetes, and Leotiomycetes all played critical roles in maintaining fungal community relationships. The effect of physicochemical properties and enzyme activities in I. cylindrica litter was significant on the dominant fungi, while driving factors that affected fungal communities differed over different recovery stages. Total nitrogen (TN), heavy metals, pH, and enzyme activities in the little were significantly correlated with fungal community composition. Litter properties throughout the litter decomposition process mainly affected the dynamics of the fungal community structure. The main environmental factors that affected fungal community structure were copper content and pH. Dichotomopilus, Trichoderma, Knufia, Phialophora, Oxyporus, and Monocillium, which all played important roles in litter decomposition, positively correlated with heavy metals, sucrase, and catalase. Finally, results from this study will help us better clarify litter decomposition mechanisms in degraded ecosystems as well as provide a scientific basis for improving species cycling and nutrient transformation efficiency in mining ecosystems.


2021 ◽  
Vol 12 ◽  
Author(s):  
Muhammad Naveed ◽  
Bisma Tanvir ◽  
Wang Xiukang ◽  
Martin Brtnicky ◽  
Allah Ditta ◽  
...  

Among heavy metals, chromium (Cr) contamination is increasing gradually due to the use of untreated industrial effluents for irrigation purposes, thereby posing a severe threat to crop production. This study aimed to evaluate the potential of compost, biochar (BC), and co-composted BC on the growth, physiological, biochemical attributes, and health risks associated with the consumption of Brassica grown on Cr-contaminated soil. Results revealed that Cr stress (Cr-25) significantly reduced the growth and physiological attributes and increased antioxidant enzyme activities in Brassica, but the applied amendments considerably retrieved the negative effects of Cr toxicity through improving the growth and physiology of plants. The maximum increase in plant height (75.3%), root length (151.0%), shoot dry weight (139.4%), root dry weight (158.5%), and photosynthetic rate (151.0%) was noted with the application of co-composted BC under Cr stress (Cr-25) in comparison to the control. The application of co-composted BC significantly reduced antioxidant enzyme activities, such as APX (42.5%), GP (45.1%), CAT (45.4%), GST (47.8%), GR (47.1%), and RG (48.2%), as compared to the control under Cr stress. The same treatment reduced the accumulation of Cr in grain, shoot, and roots of Brassica by 4.12, 2.27, and 2.17 times and enhanced the accumulation in soil by 1.52 times as compared to the control. Moreover, the application of co-composted BC significantly enhanced phytostabilization efficiency and reduced associated health risks with the consumption of Brassica. It is concluded that the application of co-composted BC in Cr-contaminated soil can significantly enhance the growth, physiological, and biochemical attributes of Brassica by reducing its uptake in plants and enhanced phytostabilization efficiency. The tested product may also help in restoring the soils contaminated with Cr.


2021 ◽  
Author(s):  
Jinqiu Guan ◽  
Chunxiang Song ◽  
Yude Wu ◽  
Xingtian Qi ◽  
Rongjun Qu ◽  
...  

Abstract Freeze-thaw cycles (FTCs) are an important element of mid and high latitude ecosystems, and significantly influence soil physicochemical properties and microbial activities in the soil active layers. With the global warming, the effects of FTCs on the dissolved organic carbon (DOC) concentration and soil enzyme activity of different types of soil were still uncertain. In this study, soil of undisturbed Deyeuxia angustifolia wetland (UDAW), disturbed Deyeuxia angustifolia wetland (DDAW) and rice paddy field (RP) from three soil layers of (0–10, 10–20 and 20–30 cm) in Sanjiang Plain, Northeast China, were collected, and then subjected to various FTCs with a large (10 to -10℃) and a small (5 to -5℃) amplitudes, respectively. The results indicated that FTCs increased the soil DOC concentration but reduced the concentration of MBC and activities of cellulase, invertase and catalase. Increase in the freeze-thaw frequency, resulted in the DOC concentration increasing initially and then decreasing, and the MBC concentration and soil enzyme activities were opposite. The DOC concentration increment resulting from the freeze-thaw effects was different across different layers and soil type: as the soil depth increased, the average DOC increments decreased, and the average DOC increments varied across different soil types: UDAW > DDAW > RP. The average MBC concentration and soil enzyme activity decreased from 0-10 cm > 10-20 cm > 20-30 cm soil depth; MBC concentration and soil enzyme activities varied across the different soil types: UDAW > DDAW > RP. The freeze-thaw amplitude and soil moisture content interaction had an effect on soil active organic carbon fractions and enzymatic activity. Small amplitude FTCs and higher water content had the greatest effect on DOC concentration, while larger amplitude and higher water content had the greatest effect on MBC concentration and enzymatic activity. In wetland soil, the significant correlations between active organic carbon fractions and enzyme activities indicate that the increased DOC by FTCs plays an important role in soil microbes and enzyme activities. However, active organic carbon fractions and enzyme activities had little correlation in RP, indicating that FTCs has more influence on wetland than farmland.


2021 ◽  
Vol 8 ◽  
Author(s):  
Kai Ziervogel ◽  
Julia Sweet ◽  
Andrew R. Juhl ◽  
Uta Passow

Sediment resuspension caused by near-bed currents mediates exchange processes between the seafloor and the overlying water column, known as benthic-pelagic coupling. To investigate the effects of sediment resuspension on microbial enzyme activities in bottom waters (<500 m), we conducted onboard erosion experiments using sediment cores taken with a multi-corer from six deep-sea sites in the northern Gulf of Mexico. We then incubated the core-top water with resuspended sediments in roller tanks to simulate bottom water conditions following sediment resuspension. Bacterial cell abundance, particulate organic matter content, and potential rates of three hydrolytic enzymes (leucine aminopeptidases – PEP; β-glucosidases – GLU, lipases – LIP) were monitored during the experimentally-generated erosion events and subsequently in the roller tanks to examine whether resuspension of deep-sea sediments enhances activities of extracellular enzymes in overlying waters. Surficial sediments were resuspended at critical shear stress velocities between 1.4 and 1.7 cm s–1, which parallel bottom water currents of 28 and 34 cm s–1. Only one of our nine cores resisted experimentally generated bottom shear stresses and remained undisturbed, possibly as a result of oil residues from natural hydrocarbon seeps at the investigated site. The most notable enzymatic responses to sediment resuspension were found for LIP activities that increased in overlying waters of all eight of our resuspended cores and remained at high levels during the roller tank incubations. PEP and GLU showed orders of magnitude lower rates and more variable responses to experimentally resuspended sediments compared with LIP. We also found a disconnect between enzyme activities and bacterial cell numbers, indicating a major role of extracellular enzymes physically disconnected from microbial cells in our experiments. Our results demonstrate that sediment resuspension may promote organic matter breakdown in bottom waters by supplying extracellular enzymes without requiring a bacterial growth response. The marked increase in LIP activity suggests that resuspended enzymes may affect the degradation of petroleum hydrocarbons, including those from the natural seeps that are abundant in the investigation area.


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