scholarly journals Biochemical characterisation of α-amylase in two aphid species, Aphis fabae Scopoli (Hemiptera: Aphididae) and A. gossypii Glover (Hemiptera: Aphididae)

2014 ◽  
Vol 50 (No. 2) ◽  
pp. 84-89 ◽  
Author(s):  
A. Darvishzadeh ◽  
A. Bandani ◽  
S.Q. Mousavi
Keyword(s):  
Soluble Starch ◽  
Aphid Species ◽  
Aphis Fabae ◽  
Alpha Amylase ◽  
Insect Species ◽  
Zymogram Analysis ◽  
Biochemical Characterisation ◽  
Optimum Ph ◽  
Optimum Ph And Temperature ◽  
Alpha Amylases

We identify and characterise α-amylases of the two aphid species, A. fabae and A. gossypi. To do this, α-amylases of the two insect species were extracted and their activities were determined using 1% soluble starch. Results showed that α-amylase, which hydrolyses starch, is present in both aphids. Also, it was shown that optimum pH and temperature for the α-amylases of both species is 7.0 and 40°C, respectively. Gel assays using zymogram analysis showed that in both aphid species more than one isoform (two isoforms) of α-amylases hydrolyszing carbohydrates are present.  

STUDY REGARDING THE APHIDOFAGOUS FAUNA STRUCTURE IN THE PEACH ORCHARDS FROM CONSTANTA COUNTY IN 2020

2020 ◽  
Vol 13 ◽  
pp. 110-114
Author(s):  
Andrei Chiriloaie-Palade ◽  
Mădălina Radulea ◽  
Gheorghe Lămureanu ◽  
Ștefan Ion Mocanu ◽  
Maria Iamandei
Keyword(s):  
Myzus Persicae ◽  
Management System ◽  
Green Peach Aphid ◽  
Aphid Species ◽  
Insect Species ◽  
Essential Component ◽  
Intensive Use ◽  
Predatory Insect ◽  
Predatory Insects ◽  
Aphid Populations

"The cosmopolitan aphid species Myzus persicae is a key pest of peach orchards in south and southeastern Romania. The phenomenon of resistance induced by the intensive use of insecticides is a matter of concern for farmers and protectionists, making necessary integrated measure for the control of this pest. Conservation of natural enemy’s populations is an essential component of any management system proposed for pest aphids. The aim of the study was to determine the structure of predatory insects associated with Myzus persicae populations in peach orchards. The research was carried out in three orchards from two localities from Constanta County, in peach plantations with Springcrest variety aged 7, 11 and 12 years. As a result of this study, there were determined a total of 15 predatory insect species belonging to eight systematic families: Coccinellidae, Chrysopidae, Hemerobiidae, Syrphydae, Cecidomyiidae, Panorpidae, Nabidae and Forficulidae, which naturally contribute to the reduction of the green peach aphid populations. "

scholarly journals Immobilization of alpha-amylase produced by Bacillus circulans GRS 313

2003 ◽  
Vol 46 (2) ◽  
pp. 167-176 ◽  
Author(s):  
Gargi Dey ◽  
Singh Bhupinder ◽  
Rintu Banerjee
Keyword(s):  
Calcium Alginate ◽  
Immobilized Enzyme ◽  
Fold Increase ◽  
Alginate Beads ◽  
Hydrolysis Kinetics ◽  
Initial Activity ◽  
Reaction Conditions ◽  
Bead Size ◽  
Optimum Ph ◽  
Optimum Ph And Temperature

A maltooligosaccharide-forming amylase from B circulans GRS 313 was immobilized by entrapment in calcium alginate beads. The immobilized activity was affected by the size of the bead and bead size of 2mm was found to be most effective for hydrolysis. Kinetics constants, Km and Vmax were estimated and were found to be affected by the bead size. The catalytic activity of the enzyme was studied in presence of various starchy residues and metal ions. HgCl2, CuSO4 and FeCl3 caused inhibition of the enzyme. The reaction conditions, pH and temperature, was optimized using response surface methodology. At the optimum pH and temperature of 4.9 and 57ºC, the apparent activity was 25.6U/g of beads, resulting in almost 2-fold increase in activity. The immobilized enzyme showed a high operational stability by retaining almost 85% of the initial activity after seventh use.

scholarly journals Potentials of the Extracts of Algerian Saharan Plant Cotula cinerea for the Management of Two Insect Pests, Aphis fabae and Tribolium castaneum

2020 ◽  
Vol 15 (2) ◽  
pp. 41-57
Author(s):  
Fatma Acheuk ◽  
◽  
Kemais Abdellaoui ◽  
Wassima Lakhdari ◽  
Nora Chahbar ◽  
...  
Keyword(s):  
Tribolium Castaneum ◽  
Insect Pests ◽  
Ethanolic Extract ◽  
Aphis Fabae ◽  
Insect Species ◽  
Contact Toxicity ◽  
Phytochemical Study ◽  
Insecticidal Effect ◽  
Cotula Cinerea ◽  
Synergetic Action

The insecticidal potential of the Saharan plant Cotula cinerea, was evaluated on two insect species namely Aphis fabae and Tribolium castaneum by topical application (contact toxicity) and repellency test. A crude ethanolic extract of aerial part of the plant was prepared and tested in the laboratory on adults of both species. For contact toxicity, five doses were tested on each of the two species 1.56, 3.12, 6.25, 12.5 and 25 mg/ml for A. fabae and 25, 50, 250, 350 and 500 µg/insect for T. castaneum. The repellency of the extract was studied at the dose 500 μg/insect for T. castaneum and 25 µg/ml for A. fabae. Results showed that the repellency of the extract increased with exposure time and the highest rates were observed after 4 h of exposure (72.33 ± 22% for T. castaneum and 87 ± 3.6% for A. fabae). For insecticidal activity, at the highest doses (25 mg/ml and 500 µg/ml), 100% mortality is obtained 72 h after treatment for A. fabae and after 48 h for T. castaneum. The extract of this plant was found to be more toxic against T. castaneum adults. LD50 calculated 24 h after treatment for the two species is estimated at 1.7 mg/ml for A. fabae and at 30.3 µg/insect for T. castaneum. The extract of this plant inhibited the activity of acetylcholinesterase (AChE) in both insect species. This result suggests that this plant has a neurotoxic effect on A. fabae and T. castaneum. The results of phytochemical study showed that the plant is mainly rich in flavonoids, gallic tannins, alkaloids, saponosides and glucosides. The insecticidal effect obtained in this study could be due to the synergetic action of all constituents of the extract. Results suggest the possibility of using the extracts of this plant in integrated pest management to replace the chemical insecticides.

scholarly journals Modulation of Aphid Vector Activity by Potato virus Y on In Vitro Potato Plants

Plant Disease ◽  
2012 ◽  
Vol 96 (1) ◽  
pp. 82-86 ◽  
Author(s):  
S. Boquel ◽  
C. Delayen ◽  
A. Couty ◽  
P. Giordanengo ◽  
A. Ameline
Keyword(s):  
Feeding Behavior ◽  
Potato Virus ◽  
Potato Virus Y ◽  
Aphid Species ◽  
Aphis Fabae ◽  
Plant Colonization ◽  
Electrical Penetration Graph ◽  
Vector Activity ◽  
Aphid Feeding

The effects of the infection of potato (Solanum tuberosum) plants by the nonpersistent Potato virus Y (PVY) were studied on the host plant colonization behavior of different colonizing (Myzus persicae) and noncolonizing (Aphis fabae, Brevicoryne brassicae, and Sitobion avenae) aphid species. The underlying questions of this study were to know how aphids respond when faced with PVY-infected plants and whether plant infection can modify the aphid behavior involved in PVY spread. Short-range orientation behavior was observed using a dual-choice set-up and aphid feeding behavior was monitored using the electrical penetration graph technique. None of the aphid species discriminated between healthy and PVY-infected plants. Nevertheless, most individuals of M. persicae landed on and probed only in one plant whereas noncolonizing aphid species exhibited interplant movements. Study of the aphid feeding behavior showed that PVY infection essentially modified phloem and xylem ingestion. M. persicae and S. avenae exhibited an increased duration of phloem phases on PVY-infected plants whereas A. fabae showed a decreased duration of phloem phases that benefited from an increased duration of xylem ingestion phases. None of these parameters were changed in B. brassicae. These data present evidence that aphids can respond to plants infected by nonpersistent viruses. Such behavioral modifications are discussed within the context of PVY spread in potato crops.

scholarly journals Purification and Characterization of a Feruloyl Esterase from the Intestinal Bacterium Lactobacillus acidophilus

2004 ◽  
Vol 70 (4) ◽  
pp. 2367-2372 ◽  
Author(s):  
Xiaokun Wang ◽  
Xin Geng ◽  
Yukari Egashira ◽  
Hiroo Sanada
Keyword(s):  
Lactobacillus Acidophilus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Hydrophobic Interaction Chromatography ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Feruloyl Esterase ◽  
Intestinal Bacterium ◽  
Optimum Ph ◽  
Optimum Ph And Temperature

ABSTRACT Dietary ferulic acid (FA), a significant antioxidant substance, is currently the subject of extensive research. FA in cereals exists mainly as feruloylated sugar ester. To release FA from food matrices, it is necessary to cleave ester cross-linking by feruloyl esterase (FAE) (hydroxycinnamoyl esterase; EC 3.1.1.73). In the present study, the FAE from a human typical intestinal bacterium, Lactobacillus acidophilus, was isolated, purified, and characterized for the first time. The enzyme was purified in successive steps including hydrophobic interaction chromatography and anion-exchange chromatography. The purified FAE appeared as a single band in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with an apparent molecular mass of 36 kDa. It has optimum pH and temperature characteristics (5.6 and 37°C, respectively). The metal ions Cu2+ and Fe3+ (at a concentration of 5 mmol liter−1) inhibited FAE activity by 97.25 and 94.80%, respectively. Under optimum pH and temperature with 5-O-feruloyl-l-arabinofuranose (FAA) as a substrate, the enzyme exhibited a K m of 0.0953 mmol liter−1 and a V max of 86.27 mmol liter−1 min−1 mg−1 of protein. Furthermore, the N-terminal amino acid sequence of the purified FAE was found to be A R V E K P R K V I L V G D G A V G S T. The FAE released FA from O-(5-O-feruloyl-α-l-arabinofuranosyl)-(1→3)-O-β-d-xylopyranosyl-(1→4)-d-xylopyranose (FAXX) and FAA obtained from refined corn bran. Moreover, it released two times more FA from FAXX in the presence of added xylanase.

Characteristics of the major DNA polymerases found during early and late maize germination

1988 ◽  
Vol 66 (6) ◽  
pp. 1186-1191 ◽  
Author(s):  
Alejandra Vazquez ◽  
Jorge Vazquez-Ramos
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerases ◽  
Absolute Requirement ◽  
Optimum Ph ◽  
Embryo Axes ◽  
The Difference ◽  
Alpha Type ◽  
Degree Of Purification ◽  
Optimum Ph And Temperature

Two types of DNA synthesis have been detected during maize germination (0–24 h). To determine if the difference in these two types of synthesis was due to the presence of distinct DNA polymerases, we partially isolated and characterized the enzymes present at 3 (early) and 24 (late) h of germination. The material used was embryo axes. The result indicates that at both 3 and 24 h, enzymes are similar with regard to optimum pH and temperature, absolute requirement of Mg2+ (12 mM), and stimulation by KCl (50 mM). They are also equally inhibited by N-ethylmaleimide and cytosine-β-D-arabinofuranoside. These facts would classify the enzymes as alpha type; however, the enzymes differ in their sensitivity to aphidicolin and the degree of purification. The nature of the enzymes is discussed.

A new method for the adaptive determination of optimum pH and temperature

1989 ◽  
Vol 33 (11) ◽  
pp. 1419-1424 ◽  
Author(s):  
Jeff. L Harmon ◽  
Gerasimos Lyberatos ◽  
Spyros A. Svoronos
Keyword(s):  
New Method ◽  
Optimum Ph ◽  
Optimum Ph And Temperature

scholarly journals Biochemical and Structural Characterization of Amy1: An Alpha-Amylase from Cryptococcus flavus Expressed in Saccharomyces cerevisiae

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Alexsandro Sobreira Galdino ◽  
Roberto Nascimento Silva ◽  
Muriele Taborda Lottermann ◽  
Alice Cunha Morales Álvares ◽  
Lídia Maria Pepe de Moraes ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Soluble Starch ◽  
Alpha Amylase ◽  
Enzyme Specificity ◽  
Wild Type ◽  
Spectra Analysis ◽  
Exclusion Chromatography ◽  
The Difference ◽  
Thermal Stability Of

An extracellular alpha-amylase (Amy1) whose gene from Cryptococcus flavus was previously expressed in Saccharomyces cerevisiae was purified to homogeneity (67 kDa) by ion-exchange and molecular exclusion chromatography. The enzyme was activated by NH4+ and inhibited by Cu+2 and Hg+2. Significant biochemical and structural discrepancies between wild-type and recombinant α-amylase with respect to Km values, enzyme specificity, and secondary structure content were found. Far-UV CD spectra analysis at pH 7.0 revealed the high thermal stability of both proteins and the difference in folding pattern of Amy1 compared with wild-type amylase from C. flavus, which reflected in decrease (10-fold) of enzymatic activity of recombinant protein. Despite the differences, the highest activity of Amy1 towards soluble starch, amylopectin, and amylase, in contrast with the lowest activity of Amy1w, points to this protein as being of paramount biotechnological importance with many applications ranging from food industry to the production of biofuels.

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