02550nas a2200253 4500008004100000022001400041245009100055210006900146260010600215300001200321490000700333520162700340653002301967653000901990653003201999653001902031653001602050100002402066700002202090700002802112700002102140700002002161856011502181 2009 eng d a0022-191000aResponses of midgut amylases of Helicoverpa armigera to feeding on various host plants0 aResponses of midgut amylases of Helicoverpa armigera to feeding  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcAUG a663-6700 v553 a

Midgut digestive amylases and proteinases of Helicoverpa armigera, a polyphagous and devastating insect pest of economic importance have been studied. We also identified the potential of a sorghum amylase inhibitor against H. armigera midgut amylase. Amylase activities were detected in all the larval instars, pupae, moths and eggs; early instars had lower amylase levels which steadily increased up to the sixth larval instar. Qualitative and quantitative differences in midgut amylases of H. amigera upon feeding on natural and artificial diets were evident. Natural diets were categorized as one or more members of legumes, vegetables, flowers and cereals belonging to different plant families. Amylase activity and isoform patterns varied depending on host plant and/or artificial diet. Artificial diet-fed H. armigera larvae had comparatively high amylase activity and several unique amylase isoforms. Correlation of amylase and proteinase activities of H. armigera with the protein and carbohydrate content of various diets suggested that H. armigera regulates the levels of these digestive enzymes in response to macromolecular composition of the diet. These adjustments in the digestive enzymes of H. armigera may be to obtain better nourishment from the diet and avoid toxicity due to nutritional imbalance. H. armigera, a generalist feeder experiences a great degree of nutritional heterogeneity in its diet. An investigation of the differences in enzyme levels in response to macronutrient balance and imbalance highlight their importance in insect nutrition. (C) 2009 Elsevier Ltd. All rights reserved.

10aAmylase inhibitors10aDiet10aHelicoverpa armigera larvae10aMidgut amylase10aProteinases1 aKotkar, Hemlata, M.1 aSarate, Priya, J.1 aTamhane, Vaijayanti, A.1 aGupta, Vidya, S.1 aGiri, Ashok, P. uhttp://library.ncl.res.in/content/responses-midgut-amylases-helicoverpa-armigera-feeding-various-host-plants-002456nas a2200253 4500008004100000022001400041245017200055210006900227260006700296300001400363490000700377520145800384653002301842653002301865653001301888653002901901653002301930100002501953700002801978700002002006700002302026700003002049856012302079 2011 eng d a0022-514200aBiochemical characterisation of alpha-amylase inhibitors from achyranthes aspera and their interactions with digestive amylases of coleopteran and lepidopteran insects0 aBiochemical characterisation of alphaamylase inhibitors from ach a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcAUG a1773-17800 v913 a

BACKGROUND: Starchy seeds are an important food and a source of dietary ingredients in many countries. However, they suffer from extensive predation by bruchids (weevils) and other pests. alpha-Amylase inhibitors are attractive candidates for the control of seed weevils, as these insects are highly dependent on starch as an energy source. RESULTS: A proteinaceous alpha-amylase inhibitor from the seeds of Achyranthes aspera was identified, purified and characterised. In electrophoretic analysis, two prominent amylase inhibitor activity bands (AI1 and AI2) were detected. The inhibitor was purified 9.99-fold with 1206.95 total amylase inhibitor units mg(-1) protein. The molecular weight of the purified inhibitor was around 6 kDa. The isolated alpha-amylase inhibitor was found to be resistant to heat and proteolysis. Feeding analysis of Callosobruchus maculatus larvae on a diet containing seed powder of A. aspera revealed that survival of the larvae was severely affected, with the highest mortality rate occurring on the fifth day of feeding. The isolated inhibitor inhibited the majority of amylase isoforms of C. maculatus, Tribolium confusum and Helicoverpa armigera in electrophoretic analysis and solution assays. CONCLUSION: The information obtained in the present investigation could be useful for a genetic engineering approach that would make seeds resistant to storage pest infestations. (C) 2011 Society of Chemical Industry

10aAchyranthes aspera10aAmylase inhibitors10aamylases10aCallosobruchus maculatus10aTribolium confusum1 aHivrale, Vandana, K.1 aChougule, Nanasaheb, P.1 aGiri, Ashok, P.1 aChhabda, Pavan, J.1 aKachole, Andmanvendra, S. uhttp://library.ncl.res.in/content/biochemical-characterisation-alpha-amylase-inhibitors-achyranthes-aspera-and-their-002745nas a2200265 4500008004100000022001400041245011600055210006900171260007300240300001400313490000900327520177500336653001902111653002302130653002202153653002002175653002502195100002002220700002402240700002302264700002102287700002602308700002002334856012502354 2015 eng d a0304-416500aBiochemical, structural and functional diversity between two digestive alpha-amylases from helicoverpa armigera0 aBiochemical structural and functional diversity between two dige aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP a1719-17280 v18503 a

Background: Helicoverpa armigera (Lepidoptera) feeds on various plants using diverse digestive enzymes as one of the survival tool-kit. The aim of the present study was to understand biochemical properties of recombinant alpha-amylases of H. armigera viz., HaAmy1 and HaAmy2. Methods: The open reading frames of HaAmy1 and HaAmy2 were cloned in Pichia pastoris and expressed heterologously. Purified recombinant enzymes were characterized for their biochemical and biophysical attributes using established methods. Results: Sequence alignment and homology modeling showed that HaAmy1 and HaAmy2 were conserved in their amino acid sequences and structures. HaAmy1 and HaAmy2 showed optimum activity at 60 degrees C; however, they differed in their optimum pH. Furthermore, HaAmy2 showed higher affinity for starch and amylopectin whereas HaAmy1 had higher catalytic efficiency. HaAmy1 and HaAmy2 were inhibited to the same magnitude by a synthetic amylase inhibitor (acarbose) while wheat amylase inhibitor showed about 2-fold higher inhibition of HaAmy1 than HaAmy2 at pH 7 while 6-fold difference at pH 11. Interactions of HaAmy1 and HaAmy2 with wheat amylase inhibitor revealed 2:1 stoichiometric ratio and much more complex interaction with HaAmy1. Conclusions: The diversity of amylases in perspective of their biochemical and biophysical properties, and their differential interactions with amylase inhibitors signify the potential role of these enzymes in adaptation of H. armigera on diverse plant diets. General significance: Characterization of digestive enzymes of H. armigera provides the molecular basis for the polyphagous nature and thus could assist in designing future strategies for the insect control. (C) 2015 Elsevier B.V. All rights reserved.

10aalpha-amylases10aAmylase inhibitors10aDigestive enzymes10aEnzyme activity10aHelicoverpa armigera1 aBhide, Amey, J.1 aChannale, Sonal, M.1 aPatil, Sucheta, S.1 aGupta, Vidya, S.1 aRamasamy, Sureshkumar1 aGiri, Ashok, P. uhttp://library.ncl.res.in/content/biochemical-structural-and-functional-diversity-between-two-digestive-alpha-amylases-0