scholarly journals Purification and characterization of a beta-Glucanase produced by Trichoderma harzianum showing biocontrol potential

2007 ◽  
Vol 50 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Janice Lisboa de Marco ◽  
Carlos Roberto Felix
Keyword(s):  
Trichoderma Harzianum ◽  
Hydrolytic Enzymes ◽  
Maximal Activity ◽  
Reducing Sugar ◽  
Phytopathogenic Fungus ◽  
Original Activity ◽  
Beta Glucanase ◽  
Apparent Homogeneity ◽  
Biocontrol Potential ◽  
Ph Range

A beta-1,3-glucanase was produced by Trichoderma harzianum in cultures containing chitin as the sole substrate. Two proteins showing beta-1,3-glucanase activity were purified to apparent homogeneity by hydrophobic chromatography. The molecular masses of these proteins were 29 and 36 kDa. The 36 kDa protein was further characterized. It was active on a broad pH range, and maximal activity was detected at pH 5.0. The optimum temperature of the 36 kDa beta-1,3-glucanase was 50ºC, but the purified enzyme was very sensitive to temperature. It lost about 60% or more of the activity after incubation for 30 min at 45, 50 and 60ºC. The apparent K M and Vmax for hydrolysis of laminarin at pH 5.0 and 37ºC, were 0.099 mg of reducing sugar/mL and 0.3 mg of reducing sugar/min.mL, respectively. The enzyme was insensitive to organic compound and metal ions, except for the ferric ion which inhibited about 100% of the original activity at the concentration of 1 mM. In contrast to other hydrolytic enzymes (a chitinase and a protease) produced by the same T. harzianum isolate (1051), the beta-1,3-glucanase showed no effect on the cell wall of the phytopathogenic fungus Crinipellis perniciosa.

scholarly journals Investigation of factors affecting xylanase activity from Trichoderma harzianum 1073 D3

2005 ◽  
Vol 48 (2) ◽  
pp. 187-193 ◽  
Author(s):  
Seyis Isil ◽  
Aksoz Nilufer
Keyword(s):  
Trichoderma Harzianum ◽  
Xylanase Activity ◽  
Stability Studies ◽  
Original Activity ◽  
Factors Affecting ◽  
Physiological Conditions ◽  
Xylanase Enzyme ◽  
Semi Solid ◽  
The Stability ◽  
Ph Range

In this study, some physiological conditions affecting the activity of xylanase enzyme produced from Trichoderma harzianum 1073 D3 were determined. In addition, stabilization of pH and temperature in liquid and semi-solid state cultivation media were investigated. It was concluded that for maximum xylanase activity, incubation at 60°C in an enzyme incubation medium with pH 5 that contained 1 % xylan was appropriate. The stability studies showed that the enzyme was relatively stable in the pH range 3-7 and retained more than 50 % of its original activity after four months.

ENZYMIC CHANGES IN THE CERVIX OF THE RAT AND HAMSTER DURING THE OESTROUS CYCLE AND THE EFFECT OF STEROIDS

1977 ◽  
Vol 72 (2) ◽  
pp. 153-161 ◽  
Author(s):  
ELIZABETH ZACHARIAH ◽  
N. R. MOUDGAL
Keyword(s):  
Alkaline Phosphatase ◽  
Specific Activity ◽  
Protein Biosynthesis ◽  
Hydrolytic Enzymes ◽  
Maximal Activity ◽  
Inhibitory Effect ◽  
Oestrous Cycle ◽  
Single Subcutaneous Injection ◽  
Arylsulphatase A ◽  
Phosphatase Alkaline

SUMMARY Changes in four hydrolytic enzymes, namely acid phosphatase, alkaline phosphatase, arylsulphatase A and B, of the cervix of the rat and hamster have been studied during the 4-day oestrous cycle. All four enzymes showed maximal activity on the day of oestrus and least activity on day 2 of dioestrus. All the enzymes showed significant reduction of activity after ovariectomy, arylsulphatase A and B showing the earliest changes in specific activity. A single subcutaneous injection of 0·02 μg oestradiol-17β/rat increased the specific activity of arylsulphatase A and B from the low ovariectomized level to that observed in control oestrous animals within 18 and 6 h respectively. A higher concentration of oestradiol-17β (2·0 μg) had an inhibitory effect. Progesterone was without effect on arylsulphatase B activity, but when given (2·0 mg) with 0·02 μg oestradiol-17β, it inhibited the response to oestrogen. Cycloheximide prevented the rise in arylsulphatase B activity occurring after oestrogen injection, suggesting a regulation of cervical arylsulphatase B at the level of protein biosynthesis. These results suggest that arylsulphatase B activity may be induced by oestrogen in the cervix of the rat.

Effect of temperature and pH on the production, activity, and stability of α-amylase from Bacillus subtilis V37

2021 ◽  
Vol 66 (1) ◽  
pp. 72-79
Author(s):  
Thuoc Doan Van ◽  
Hung Nguyen Phuc
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Animal Feed ◽  
Culture Conditions ◽  
Effect Of Temperature ◽  
Physical Parameters ◽  
Original Activity ◽  
Optimum Ph ◽  
Production Activity ◽  
Ph Range

The effect of physical parameters such as temperature and pH on the production, activity, and stability of α-amylase from Bacillus subtilis V37 was investigated. The results indicated that the optimum culture conditions for enzyme activity were pH 7.0 and 35 oC. The optimum pH and temperature for enzyme activity were 6.0 and 70 oC. The crude enzyme was found to be stable in the pH range of 5.0 to 7.0. The enzyme was stable for 1 h at a temperature from 30 to 80 oC; nearly 100% of enzyme activity remained at temperatures of 30 - 40 oC, and about 34% of original activity remained at a temperature of 80 oC. These features demonstrated that α-amylase from B. subtilis V37 can be applied in many areas such as the food, fermentation, and animal feed industries.

scholarly journals Trichoderma: a beneficial antifungal agent and insights into its mechanism of biocontrol potential

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Ria Mukhopadhyay ◽  
Deepak Kumar
Keyword(s):  
Biological Control ◽  
G Protein ◽  
Plant Pathogens ◽  
Hydrolytic Enzymes ◽  
Main Body ◽  
Antifungal Metabolites ◽  
Camp Pathway ◽  
Wide Range ◽  
Biocontrol Potential ◽  
Chemical Pesticides

Abstract Background Agriculture is an indispensable part of any country to feed the millions of people but it is under constant threat of pests. To protect the crops from this huge yield loss recently, chemical pesticides are used. Though chemical pesticides have shown effective results in killing the crop pests, it causes negative impact on the environment as well as humans. So to find an eco-friendly alternative, biological control methods are being used. Main body Biological control is a great renaissance of interest and research in microbiological balance to control soil-borne plant pathogens and leads to the development of a better farming system. In biological control, genus Trichoderma serves as one of the best bioagents, which is found to be effective against a wide range of soil and foliar pathogens. Genus Trichoderma is a soil inhabiting green filamentous fungus, which belongs to the division Ascomycota. The efficacy of Trichoderma depends on many abiotic parameters such as soil pH, water retention, temperature and presence of heavy metals. The biocontrol potential of Trichoderma spp. is due to their complex interaction with plant pathogens either by parasitizing them, secreting antibiotics or by competing for space and nutrients. During mycoparasitic interactions, production of hydrolytic enzymes such as glucanase, chitinase and protease and also signalling pathways are initiated by Trichoderma spp. and the important ones are Heterotrimeric G protein, MAP kinase and cAMP pathway. G protein and MAPK are mainly involved in secretion of antifungal metabolites and the formation of infection structures. cAMP pathway helps in the condition and coiling of Trichoderma mycelium on pathogenic fungi and inhibits their proliferation. Short conclusion Trichoderma being an efficient biocontrol agent, their characteristics and mechanisms should be well understood to apply them in field conditions to restrict the proliferation of phytopathogens.

Regulatory features of transcription in isolated mitochondria from Artemia franciscana embryos

1999 ◽  
Vol 277 (6) ◽  
pp. R1588-R1597 ◽  
Author(s):  
Brian D. Eads ◽  
Steven C. Hand
Keyword(s):  
Rna Synthesis ◽  
Maximal Activity ◽  
Artemia Franciscana ◽  
Mitochondrial Rna ◽  
Optimal Conditions ◽  
In Organello ◽  
Atp Inhibition ◽  
Bona Fide ◽  
Ph Range

Optimal conditions were developed for an in organello transcriptional run-on assay using mitochondria isolated from Artemia franciscana embryos to investigate potential regulatory features of RNA synthesis under conditions of anoxia-induced quiescence. Transcription is not dependent on oxidative phosphorylation for maximal activity when exogenous ATP is available. Bona fide transcription products, as assessed by hybridization with specific mitochondrial cDNAs from A. franciscana, are produced in an inhibitor-sensitive manner. Transcription rate measured at pH 7.9 is reduced 80% when pH is lowered to 6.3, a pH range that mimics the in vivo change seen on exposure of embryos to anoxia. The proton sensitivity of mitochondrial RNA synthesis may provide a mechanism to depress this significant energy expenditure during quiescence. The influence of nucleotide concentration on kinetics is complicated by an interdependence among nucleotide species. ATP inhibition observed at subsaturating UTP concentrations is relieved when UTP is at saturating, physiologically relevant levels. Taken together, these data suggest that local (versus nuclear mediated) control is important in dictating mitochondrial transcription during rapid modulations in gene expression, such as those observed under anoxia-induced quiescence.

scholarly journals Improvement in Thermostability of an Achaetomium sp. Strain Xz8 Endopolygalacturonase via the Optimization of Charge-Charge Interactions

2015 ◽  
Vol 81 (19) ◽  
pp. 6938-6944 ◽  
Author(s):  
Tao Tu ◽  
Huiying Luo ◽  
Kun Meng ◽  
Yanli Cheng ◽  
Rui Ma ◽  
...  
Keyword(s):  
Rational Design ◽  
Residual Activity ◽  
Maximal Activity ◽  
Wild Type ◽  
Content Type ◽  
Highly Active ◽  
Wide Ph Range ◽  
Enzyme Thermal Stability ◽  
Ph Range ◽  
Charge Interactions

ABSTRACTImproving enzyme thermostability is of importance for widening the spectrum of application of enzymes. In this study, a structure-based rational design approach was used to improve the thermostability of a highly active, wide-pH-range-adaptable, and stable endopolygalacturonase (PG8fn) fromAchaetomiumsp. strain Xz8 via the optimization of charge-charge interactions. By using the enzyme thermal stability system (ETSS), two residues—D244 and D299—were inferred to be crucial contributors to thermostability. Single (D244A and D299R) and double (D244A/D299R) mutants were then generated and compared with the wild type. All mutants showed improved thermal properties, in the order D244A < D299R < D244A/D299R. In comparison with PG8fn, D244A/D299R showed the most pronounced shifts in temperature of maximum enzymatic activity (Tmax), temperature at which 50% of the maximal activity of an enzyme is retained (T50), and melting temperature (Tm), of about 10, 17, and 10.2°C upward, respectively, with the half-life (t1/2) extended by 8.4 h at 50°C and 45 min at 55°C. Another distinguishing characteristic of the D244A/D299R mutant was its catalytic activity, which was comparable to that of the wild type (23,000 ± 130 U/mg versus 28,000 ± 293 U/mg); on the other hand, it showed more residual activity (8,400 ± 83 U/mg versus 1,400 ± 57 U/mg) after the feed pelleting process (80°C and 30 min). Molecular dynamics (MD) simulation studies indicated that mutations at sites D244 and D299 lowered the overall root mean square deviation (RMSD) and consequently increased the protein rigidity. This study reveals the importance of charge-charge interactions in protein conformation and provides a viable strategy for enhancing protein stability.

scholarly journals Deoxyribonuclease from Salmon Testes

1962 ◽  
Vol 45 (4) ◽  
pp. 77-92 ◽  
Author(s):  
Margaret R. McDonald
Keyword(s):  
Ionic Strength ◽  
Maximal Activity ◽  
Optimum Concentration ◽  
Heat Denaturation ◽  
Acid Extraction ◽  
Fractional Precipitation ◽  
Temperature Optimum ◽  
Monovalent Ions ◽  
Ph Range ◽  
Deoxyribonuclease Activity

A procedure is described for the purification of salmon testis deoxyribonuclease II by means of acid extraction, fractional precipitation with ammonium sulfate, heat denaturation of extraneous proteins, and ethanol fractionation. This process separates the deoxyribonuclease activity from that of ribonuclease, phosphatase, phosphodiesterase, and protease. Over 50 per cent of the activity is retained with an over-all enrichment of 20,000-fold. The enzyme degrades both native and heat-denatured DNA, but the rate of degradation of the latter is only one-tenth that of the former. It does not hydrolyze apurinic acid. The enzyme is most stable in the pH range 4 to 5. Electrolytes are essential for the expression of its activity: monovalent ions satisfy the requirement, but divalent ones are much more effective. Above a certain optimum concentration, each electrolyte is inhibitory. The pH of maximal activity, under conditions of optimal ionic strength, is 4.8; the temperature optimum is near to 55°C.

scholarly journals Biocontrol potential of Trichoderma harzianum in controlling wilt disease of pistachio caused by Verticillium dahliae

2017 ◽  
Vol 57 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Zeinab Fotoohiyan ◽  
Saeed Rezaee ◽  
Gholam Hosein Shahidi Bonjar ◽  
Amir Hossein Mohammadi ◽  
Mohammad Moradi
Keyword(s):  
Verticillium Dahliae ◽  
Trichoderma Harzianum ◽  
Pathogenic Fungus ◽  
Antagonistic Activity ◽  
Wilt Disease ◽  
Dual Culture ◽  
Volatile Metabolites ◽  
Biocontrol Potential

Abstract Verticillium wilt caused by Verticillium dahliae, is one of the most devastating diseases in pistachio orchards in the world including Iran. In search for an effective non-chemical strategy for the management of this disease, we evaluated the biocontrol potential of Trichoderma harzianum isolates obtained from the rhizosphere of healthy pistachio trees in different locations of the Kerman province of Iran against V. dahliae under laboratory and greenhouse conditions. Dual culture tests in the laboratory were conducted in a completely randomized design using 72 T. harzianum isolates. Twenty isolates showed the highest in vitro antagonistic activity. The results indicated that all 20 isolates were capable of inhibiting the mycelial growth of V. dahliae significantly. Among them, isolates Tr8 and Tr19 were the most effective by 88.89% and 85.12% inhibition, respectively. Extracted cell free metabolites of all effective isolates also inhibited the growth of V. dahliae in the culture medium significantly. According to the results, isolates Tr4 and Tr6 inhibited fungal pathogen growth by 94.94% and 88.15% respectively, through production of non-volatile metabolites. In the evaluation of volatile metabolites, isolates Tr5 and Tr4 were the most effective by 26.27% and 24.49% growth inhibition, respectively. Based on the results of the in vitro experiments, the five most effective isolates were selected for evaluation under greenhouse conditions for their biocontrol potential in controlling Verticillium wilt of pistachio. Results of the greenhouse, (in vivo) experiments were positive and indicated that the occurrence of wilt disease in plants treated with the antagonists alone or in combination with pathogenic fungus was lower than in plants inoculated with pathogen alone. The overall results of this study suggest that Trichoderma fungal antagonist may be an effective biocontrol agent for the control of Verticillium wilt of pistachio.

scholarly journals Production of Pectinolytic Enzymes by the Yeast Wickerhanomyces anomalus Isolated from Citrus Fruits Peels

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
María A. Martos ◽  
Emilce R. Zubreski ◽  
Oscar A. Garro ◽  
Roque A. Hours
Keyword(s):  
Single Cells ◽  
Maximal Activity ◽  
Future Application ◽  
Citrus Fruits ◽  
Enzymatic Extract ◽  
Regional Interest ◽  
Pectinolytic Enzymes ◽  
Optimum Ph ◽  
Lyase Activity ◽  
Ph Range

Wickerhamomyces anomalus is pectinolytic yeast isolated from citrus fruits peels in the province of Misiones, Argentine. In the present work, enzymes produced by this yeast strain were characterized, and polygalacturonase physicochemical properties were determined in order to evaluate the application of the supernatant in the maceration of potato tissues. W. anomalus was able to produce PG in liquid medium containing glucose and citrus pectin, whose mode of action was mainly of endo type. The supernatant did not exhibit esterase or lyase activity. No others enzymes, capable of hydrolyzing cell wall polymers, such as cellulases and xylanases, were detected. PG showed maximal activity at pH 4.5 and at temperature range between 40°C and 50°C. It was stable in the pH range from 3.0 to 6.0 and up to 50°C at optimum pH. The enzymatic extract macerated potato tissues efficiently. Volume of single cells increased with the agitation speed. The results observed make the enzymatic extract produced by W. anomalus appropriate for future application in food industry, mainly for the production of fruit nectars or mashed of vegetables such as potato or cassava, of regional interest in the province of Misiones, Argentine.

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