scholarly journals Determination of digestive proteolytic profile in the larvae of Dyspessa palidata (Staudinger) (Lepidoptera: Cossidae)

2015 ◽  
Vol 47 (3) ◽  
pp. 91
Author(s):  
M. Mardani-Talaee ◽  
A. Zibaee
Keyword(s):  
Proteolytic Activity ◽  
Cathepsin B ◽  
Posterior Midgut ◽  
Ph Dependency ◽  
Metalloproteinase Inhibitors ◽  
Optimal Value ◽  
Important Pest ◽  
Proteolytic Activities ◽  
Membrane Bound

Digestive proteolytic profile was determined in the larvae of <em>Dyspessa palidata</em> (Staudinger), which is the most important pest of Alliaceae in Europe and Iran. Compartmentalisation of the proteolytic activities by considering soluble and membrane-bound fractions revealed that soluble fractions of the whole midgut preparations had higher general proteolytic activity than membrane-bound fractions. Also, four proteolytic bands were observed in the soluble fraction of the total midgut preparation in electrophoresis. Compartmentalisation of the specific proteases revealed presence of trypsin, elastase, aminoand carboxy peptidases in posterior midgut but the highest activities of other proteases were found in anterior midgut. The highest activity of general protease was found at pHs of 6 and 8. Also, pH dependency of trypsin, chymotrypsin and elastase were found at values of 8, 7-8 and 9 but cathepsins had the optimal pH at 6. Exopeptidases showed the optimal value at pH of 7 although carboxypeptidase showed same activity at values of 6 and 7. The inhibitory concentrations 50% (IC<sub>50</sub>) of AEBSF.HCL on trypsin, chymotrypsin and elastase proteases were found to be 3.69, 3.31 and 4.09 mM, respectively. IC<sub>50</sub> concentrations of TLCK, SBTI and TPCK significantly inhibited trypsin and chymotrypsin activities. IC<sub>50</sub> of E-64 were 3.67 and 4.16 mM on cathepsin B and L but cystatin revealed 5.22 and 4.48 mM concentrations on cathepsin B and L, respectively. EDTA and phenathroline as metalloproteinase inhibitors had IC<sub>50</sub> of 3.25 and 3.91 mM on general proteolytic activity. Results of the current study revealed larvae of <em>D. palidata</em> utilised different proteases to increase digestive efficiency when they fed on the host plants containing several toxic molecules.

scholarly journals Comparison of the growth kinetics and proteolytic activities of Chryseobacterium species and Pseudomonas fluorescens

2015 ◽  
Vol 61 (12) ◽  
pp. 977-982 ◽  
Author(s):  
A. Bekker ◽  
L. Steyn ◽  
G. Charimba ◽  
P. Jooste ◽  
C. Hugo
Keyword(s):  
Temperature Gradient ◽  
Pseudomonas Fluorescens ◽  
Proteolytic Activity ◽  
Growth Kinetics ◽  
Effect Of Temperature ◽  
Time Intervals ◽  
Temperature Range ◽  
Growth Studies ◽  
Proteolytic Activities

The effect of temperature on the growth kinetics and proteolytic activity of Chryseobacterium joostei and Chryseobacterium bovis was determined during this study. The results were compared with the activities of Pseudomonas fluorescens, which is regarded to be a major food spoilage psychrotolerant microorganism. For the growth studies, cultures were incubated in nutrient broth in a temperature gradient incubator (from 9 to 50 °C) and separately at 4 °C, and the optical density was measured at different time intervals. Growth temperature profiles for each organism were constructed. For determination of proteolytic activity, the cultures were incubated in fat-free ultra-high temperature processed milk in the temperature gradient incubator for 72 h (temperature range as above). Cell-free extracts were used to determine the proteolytic activity using the azocasein method. Results of the growth studies showed that C. joostei had the ability to grow over a wider temperature range than C. bovis and P. fluorescens without being affected by changes in the temperature. For the proteolytic activity, C. joostei had significantly (p < 0.001) higher activity per milligram of protein at 15.5 °C, followed by C. bovis and P. fluorescens. The results showed that C. joostei potentially has an even greater spoilage capacity in milk on the basis of growth rate and proteolytic activity than did P. fluorescens.

scholarly journals Digestive proteolytic activity in Apodiphus amygdali Germar (Hemiptera: Pentatomidae): effect of endogenous inhibitors

2014 ◽  
Vol 46 (2) ◽  
pp. 35 ◽  
Author(s):  
S. Ramzi ◽  
A. Zibaee
Keyword(s):  
Proteolytic Activity ◽  
Cathepsin B ◽  
Cathepsin L ◽  
Negative Control ◽  
Significant Inhibition ◽  
Chloromethyl Ketone ◽  
Crop Varieties ◽  
Ph Dependency ◽  
Ph Range ◽  
Specific Inhibitors

The digestive proteolytic profile of <em>Apodiphus amygdali</em> was determined by using several substrates and specific inhibitors. Analysis of optimal pH and temperature showed the highest enzymatic activity at the pH range of 6-7 and temperature of 40°C when azocasein was used as a substrate. By using a negative control, the presence of several specific proteases were determined including tryspin-like, chymotrypsinlike, elastase, cathepsin B, cathepsin L, amino- and carboxypeptidases in the midgut content of <em>A. amygdali</em>, with the highest and the lowest activities of cathepsin L and carboxypeptidase, respectively. pH dependency of specific proteases revealed optimal pHs of 9, 8 and 9 for trypsin-, chymotrypsin-like, 6 for cathepsins and 5-6 for carboxy- and aminopeptidases, respectively. Specific inhibitors, including phenylmethylsulfonyl fluoride, Na-p-tosyl-L-lysine chloromethyl ketone, Ntosyl- L-phenylalanine chloromethyl ketone, L-trans-epoxysuccinylleucylamido-(4-guanidino)-butane, phenanthroline and ethylendiamidetetraacetic acid, significantly decreased proteolytic activity, indicating the presence of different proteases in the midgut of <em>A. amygdali</em>. Extracted inhibitors from the midgut demonstrated significant inhibition of specific proteolytic activities of <em>A. amygdali</em> except for cathepsin B and aminopeptidase. The results indicated that determination of digestive proteolytic activity could be helpful to clarify digestion process in insects. Moreover, understanding the nature of digestive proteases might be used to develop several inhibitors for providing resistant crop varieties against pests.

scholarly journals A PROCEDURE FOR THE DETERMINATION OF PROTEOLYTIC ACTIVITY

1950 ◽  
Vol 182 (2) ◽  
pp. 821-828
Author(s):  
Beat M. Iselin ◽  
Carl. Niemann
Keyword(s):  
Proteolytic Activity

Resistance of Phlebotomus papatasi to infection with Leishmania donovani is modulated by components of the infective bloodmeal

Parasitology ◽  
1998 ◽  
Vol 117 (5) ◽  
pp. 467-473 ◽  
Author(s):  
Y. SCHLEIN ◽  
R. L. JACOBSON
Keyword(s):  
Proteolytic Activity ◽  
Trypsin Inhibitor ◽  
Alkaline Protease ◽  
Protease Activity ◽  
Leishmania Donovani ◽  
Blood Feeding ◽  
Growth Conditions ◽  
Enzymatic Activities ◽  
Phlebotomus Papatasi ◽  
Proteolytic Activities

The circumstances which permit the establishment of Leishmania infections in sandflies were investigated by altering the growth conditions for L. donovani parasites in the unsuitable vector Phlebotomus papatasi. Only 5·0% of the sandflies harboured a few parasites 3 days after feeding on promastigotes in defibrinated blood. Heparinized blood or the addition of trypsin inhibitor to the meals allowed persistence of infections (day 6) in 9·9% and 25·8% of the flies respectively. Meals of erythrocytes, saline and amastigotes produced 44·4% fly infection on day 6, while similar promastigote-initiated infections remained in 70·3% of the flies. Proteolytic activities in the guts of sandflies fed on the above meals without parasites, were the highest after defibrinated bloodmeals. Erythrocytes with saline decreased the maximal alkaline protease level from 20·8 U to 13·5 U/fly; that of trypsin from 3·9 U to 1·8 U/fly and that of the aminopeptidase from 5·5 U to 3·9 U/fly. After meals of heparinized blood, the maximal alkaline protease activity (12·0 U/fly) was also much lower than after defibrinated blood-feeding. The different diets which resulted in comparatively low enzymatic activities, including blood with trypsin inhibitor, also promoted the survival of infections. This implies that the proteolytic activity in the sandfly gut modulates the vector susceptibility.

scholarly journals Determination of 15N Chemical Shift Anisotropy from a Membrane-Bound Protein by NMR Spectroscopy

2012 ◽  
Vol 116 (24) ◽  
pp. 7181-7189 ◽  
Author(s):  
Manoj Kumar Pandey ◽  
Subramanian Vivekanandan ◽  
Shivani Ahuja ◽  
Kumar Pichumani ◽  
Sang-Choul Im ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Shift ◽  
Chemical Shift Anisotropy ◽  
Membrane Bound

scholarly journals A Methodology for Optimal Design of Transmission Lines to Protection against Lightning Surges in Presence of Arresters

2020 ◽  
Vol 9 (1) ◽  
pp. 105-110
Author(s):  
R. Shariatinasab ◽  
R. Azimi
Keyword(s):  
Transmission Lines ◽  
Geometric Model ◽  
Design Parameters ◽  
Target Number ◽  
Planning Stage ◽  
Shielding Failure ◽  
Surge Arresters ◽  
The Monte Carlo Method ◽  
Optimal Value

In this paper, a methodology for determination of the optimal value of protection design parameters, i.e. tower footing resistance, insulation strength, and surge arresters’ rating in the planning stage of transmission lines (TLs) is presented. This method calculates the shielding failure flashover rate (SFFOR) of TLs, based on Electro-geometric model (EGM) of TLs, and the back flashover rate (BFR) of TLs, based on the Monte Carlo method, in which the accuracy of the proposed methodology has been verified by comparing the resultant results with those obtained with the use of the IEEE FLASH program. The proposed method can be directly used to achieve the minimum lightning flashover rate (LFOR) of TLs by the minimum investment cost. Also, it can be used, indirectly, for determination of the appropriate value of the footing resistance, insulation strength and arresters’ rating to satisfy any target number of LFOR that might be specified by the utilities or standards.

scholarly journals H.p.l.c. of oligo(sialic acids). Application to the determination of the minimal chain length serving as exogenous acceptor in the enzymic synthesis of colominic acid

1991 ◽  
Vol 280 (3) ◽  
pp. 575-579 ◽  
Author(s):  
M A Ferrero ◽  
J M Luengo ◽  
A Reglero
Keyword(s):  
Chain Length ◽  
Complete Separation ◽  
Sialic Acids ◽  
Degree Of Polymerization ◽  
Direct Transfer ◽  
Maximal Rate ◽  
Colominic Acid ◽  
Membrane Bound

A rapid, sensitive and easy h.p.l.c. method was developed for the quantitative analysis of oligosialic acids. This procedure which permits the complete separation (in 23 min) of several sialyloligomers with a degree of polymerization of between 1 and 16, has been employed to establish the minimal chain length of oligomer accepted, as an exogenous acceptor, by Escherichia coli K-235 sialytransferase complex (ST) leading to the synthesis in vitro of colominic acid. We showed that this membrane-bound enzyme catalyses the direct transfer of Neu5Ac residues (one by one) from CMP-Neu5Ac to an exogenous acceptor molecule which contains at least three Neu5Ac residues. Free Neu5Ac or (Neu5Ac)2 were not recognized as substrates, whereas the maximal rate of polymer elongation was achieved when (Neu5Ac)5 was used as substrate.

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