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T J V Higgins - One of the best experts on this subject based on the ideXlab platform.
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heterologous expression of an α Amylase Inhibitor from common bean phaseolus vulgaris in kluyveromyces lactis and saccharomyces cerevisiae
Microbial Cell Factories, 2017Co-Authors: Stephanie Brainisasi, A Alvarezlueje, T J V HigginsAbstract:Phaseolamin or α-Amylase Inhibitor 1 (αAI) is a glycoprotein from common beans (Phaseolus vulgaris L.) that inhibits some insect and mammalian α-Amylases. Several clinical studies support the beneficial use of bean αAI for control of diabetes and obesity. Commercial extracts of P. vulgaris are available but their efficacy is still under question, mainly because some of these extracts contain antinutritional impurities naturally present in bean seeds and also exhibit a lower specific activity αAI. The production of recombinant αAI allows to overcome these disadvantages and provides a platform for the large-scale production of pure and functional αAI protein for biotechnological and pharmaceutical applications. A synthetic gene encoding αAI from the common bean (Phaseolus vulgaris cv. Pinto) was codon-optimised for expression in yeasts (αAI-OPT) and cloned into the protein expression vectors pKLAC2 and pYES2. The yeasts Kluyveromyces lactis GG799 (and protease deficient derivatives such as YCT390) and Saccharomyces cerevisiae YPH499 were transformed with the optimised genes and transformants were screened for expression by antibody dot blot. Recombinant colonies of K. lactis YCT390 that expressed and secreted functional αAI into the culture supernatants were selected for further analyses. Recombinant αAI from K. lactis YCT390 was purified using anion-exchange and affinity resins leading to the recovery of a functional Inhibitor. The identity of the purified αAI was confirmed by mass spectrometry. Recombinant clones of S. cerevisiae YPH499 expressed functional αAI intracellularly, but did not secrete the protein. This is the first report describing the heterologous expression of the α-Amylase Inhibitor 1 (αAI) from P. vulgaris in yeasts. We demonstrated that recombinant strains of K. lactis and S. cerevisiae expressed and processed the αAI precursor into mature and active protein and also showed that K. lactis secretes functional αAI.
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Genetically Modified α-Amylase Inhibitor Peas Are Not Specifically Allergenic in Mice
2013Co-Authors: Ruiyun Lee, T J V Higgins, Daniela Reiner, Andrew E Moore, Gerhard Dekan, Michelle M EpsteinAbstract:Weevils can devastate food legumes in developing countries, but genetically modified peas (Pisum sativum), chickpeas and cowpeas expressing the gene for alpha-Amylase Inhibitor-1 (αAI) from the common bean (Phaseolus vulgaris) are completely protected from weevil destruction. αAI is seed-specific, accumulated at high levels and undergoes post-translational modification as it traverses the seed endomembrane system. This modification was thought to be responsible for the reported allergenicity in mice of the transgenic pea but not the bean. Here, we observed that transgenic αAI peas, chickpeas and cowpeas as well as non-transgenic beans were all allergenic in BALB/c mice. Even consuming non-transgenic peas lacking αAI led to an anti-αAI response due to a cross-reactive response to pea lectin. Our data demonstrate that αAI transgenic peas are not more allergenic than beans or non-transgenic peas in mice. This study illustrates the importance of repeat experiments in independent laboratories and the potential for unexpected cross-reactive allergic responses upon consumption of plant products in mice.
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comparison of the α Amylase Inhibitor 1 from common bean phaseolus vulgaris varieties and transgenic expression in other legumes post translational modifications and immunogenicity
Journal of Agricultural and Food Chemistry, 2011Co-Authors: Peter M Campbell, Daniela Reiner, Andrew E Moore, Ruiyun Lee, Michelle M Epstein, T J V HigginsAbstract:The seeds of peas (Pisum sativum) and chickpeas (Cicer arietinum) expressing a gene for α-Amylase Inhibitor-1 (αAI) from the common bean (Phaseolus vulgaris) are protected from damage by old world ...
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unintended changes in protein expression revealed by proteomic analysis of seeds from transgenic pea expressing a bean α Amylase Inhibitor gene
Proteomics, 2009Co-Authors: Hancai Chen, T J V Higgins, Greg Bodulovic, Prudence J Hall, Andrew D Moore, Michael A Djordjevic, Barry G RolfeAbstract:Seeds of genetically modified (GM) peas (Pisum sativum L.) expressing the gene for alpha-Amylase Inhibitor-1 (alphaAI1) from the common bean (Phaseolus vulgaris L. cv. Tendergreen) exhibit resistance to the pea weevil (Bruchus pisorum). A proteomic analysis was carried out to compare seeds from GM pea lines expressing the bean alphaAI1 protein and the corresponding alphaAI1-free segregating lines and non-GM parental line to identify unintended alterations to the proteome of GM peas due to the introduction of the gene for alphaAI1. Proteomic analysis showed that in addition to the presence of alphaAI1, 33 other proteins were differentially accumulated in the alphaAI1-expressing GM lines compared with their non-GM parental line and these were grouped into five expression classes. Among these 33 proteins, only three were found to be associated with the expression of alphaAI1 in the GM pea lines. The accumulation of the remaining 30 proteins appears to be associated with Agrobacterium-mediated transformation events. Sixteen proteins were identified after MALDI-TOF-TOF analysis. About 56% of the identified proteins with altered accumulation in the GM pea were storage proteins including legumin, vicilin or convicilin, phaseolin, cupin and valosin-containing protein. Two proteins were uniquely expressed in the alphaAI1-expressing GM lines and one new protein was present in both the alphaAI1-expressing GM lines and their alphaAI1-free segregating lines, suggesting that both transgenesis and transformation events led to demonstrable changes in the proteomes of the GM lines tested.
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starch but not protein digestibility is altered in pigs fed transgenic peas containing α Amylase Inhibitor
Journal of the Science of Food and Agriculture, 2006Co-Authors: C L Collins, Paul Eason, T J V Higgins, Frank R. Dunshea, Ray H KingAbstract:Eighteen individually housed boars were randomly allocated to one of three dietary treatments, an experimental wheat diet containing 989.4 g kg−1 of a basal wheat diet, or this experimental wheat diet with 500 g kg−1 of the basal wheat diet replaced with 500 g kg−1 of either transgenic or non-transgenic peas. The transgenic peas expressed the bean (Phaseolus vulgaris L.) α-Amylase Inhibitor 1 gene. Diets contained n-hexatriacontane (0.2 g kg−1) as an indigestible marker to allow the determination of nutrient digestibility at the terminal ileum. Pigs were offered 1.6 kg day−1 for 15 days, after which they were anaesthetised, the ileal and faecal digesta collected and the pigs subsequently euthanased. The ileal dry matter and starch digestibilities of the experimental wheat, non-transgenic and transgenic pea diets were 78.3, 74.2 and 45.8% and 95.9, 95.2 and 42.4%, respectively. The apparent nutrient digestibilities of the non-transgenic and transgenic peas were determined by difference. The ileal dry matter digestibility was significantly reduced in the transgenic peas compared with the non-transgenic peas (12.7 and 69.9%, respectively; P = 0.006), which was largely due to a reduced starch digestibility. The apparent crude protein digestibilities of the transgenic peas were similar to the non-transgenic, being 79.7 and 78.5%, respectively. The amino acid digestibilities of the transgenic and non-transgenic peas were also similar. Copyright © 2006 Society of Chemical Industry
Maarten J. Chrispeels - One of the best experts on this subject based on the ideXlab platform.
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α-Amylases of the coffee berry borer (Hypothenemus hampei ) and their inhibition by two plant Amylase Inhibitors
Insect biochemistry and molecular biology, 2000Co-Authors: Arnubio Valencia, Alex E Bustillo, Gustavo E Ossa, Maarten J. ChrispeelsAbstract:Abstract The adult coffee berry borer ( Hypothenemus hampei Ferrari [Coleoptera: Scolytidae]), a major insect pest of coffee, has two major digestive α-Amylases that can be separated by isoelectric focusing. The α-Amylase activity has a broad pH optimum between 4.0 and 7.0. Using pH indicators, the pH of the midgut was determined to be between 4.5 and 5.2. At pH 5.0, the coffee berry borer α-Amylase activity is inhibited substantially (80%) by relatively low levels of the Amylase Inhibitor (αAI-1) from the common bean, Phaseolus vulgaris L., and much less so by the Amylase Inhibitor from Amaranthus . We used an in-gel zymogram assay to demonstrate that seed extracts can be screened to find suitable Inhibitors of Amylases. The prospect of using the genes that encode these Inhibitors to make coffee resistant to the coffee berry borer via genetic engineering is discussed.
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expression of the insecticidal bean α Amylase Inhibitor transgene has minimal detrimental effect on the nutritional value of peas fed to rats at 30 of the diet
Journal of Nutrition, 1999Co-Authors: Arpad Pusztai, Maarten J. Chrispeels, Grant G S Bardocz, Ruben Alonso, Hartmut E Schroeder, Linda Tabe, T J V HigginsAbstract:The effect of expression of bean alpha-Amylase Inhibitor (alpha-AI) transgene on the nutritional value of peas has been evaluated by pair-feeding rats diets containing transgenic or parent peas at 300 and 650 g/kg, respectively, and at 150 g protein/kg diet, supplemented with essential amino acids to target requirements. The results were also compared with the effects of diets containing lactalbumin with or without 0.9 or 2.0 mg bean alpha-AI, levels equivalent to those in transgenic pea diets. When 300 and 650 g peas/kg diet were fed, the daily intake of alpha-AI was 11.5 or 26.3 mg alpha-AI, respectively. At the 300 g/kg level, the nutritional value of the transgenic and parent line peas was not significantly different. The weight gain and tissue weights of rats fed either of the two pea diets were not significantly different from each other or from those of rats given the lactalbumin diet even when this was supplemented with 0.9 g alpha-AI/kg. The digestibilities of protein and dry matter of the pea diets were slightly but significantly lower than those of the lactalbumin diet, probably due to the presence of naturally occurring antinutrients in peas. The nutritional value of diets containing peas at the higher (650 g) inclusion level was less than that of the lactalbumin diet. However, the differences between transgenic and parent pea lines were small, possibly because neither the purified recombinant alpha-AI nor that in transgenic peas inhibited starch digestion in the rat small intestine in vivo to the same extent as did bean alpha-AI. This was the case even though both forms of alpha-AI equally inhibited alpha-Amylase in vitro. Thus, this short-term study indicated that transgenic peas expressing bean alpha-AI gene could be used in rat diets at 300 g/kg level without major harmful effects on their growth, metabolism and health, raising the possibility that transgenic peas may also be used at this level in the diet of farm animals.
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molecular characterization of a bean α Amylase Inhibitor that inhibits the α Amylase of the mexican bean weevil zabrotes subfasciatus
Planta, 1997Co-Authors: T E Mirkov, Masao Ishimoto, G Colucci, K S Bateman, Maarten J. ChrispeelsAbstract:Cultivated varieties of the common bean (Phaseolus vulgaris L.) contain an α-Amylase Inhibitor (αAI-1) that inhibits porcine pancreatic α-Amylase (PPA; EC 3.2.1.1) and the Amylases of certain seed weevils, but not that of the Mexican bean weevil, Zabrotes subfasciatus. A variant of αAI-1, called αAI-2, is found in certain arcelin-containing wild accessions of the common bean. The variant αAI-2 inhibits Z. subfasciatus α-Amylase (ZSA), but not PPA. We purified αAI-2 and studied its interaction with ZSA. The formation of the αAI-2-ZSA complex is time-dependent and occurs maximally at pH 5.0 or below. When a previously isolated cDNA assumed to encode αAI-2 was expressed in transgenic tobacco seeds, the seeds contained Inhibitory activity toward ZSA but not toward PPA, confirming that the cDNA encodes αAI-2. The Inhibitors αAI-1 and αAI-2 share 78% sequence identity at the amino acid level and they differ in an important region that is part of the site where the enzyme binds the Inhibitor. The swap of a tripeptide in this region was not sufficient to change the specificity of the two Inhibitors towards their respective enzymes. The three-dimensional structure of the αAI-1/PPA complex has just been solved and we recently obtained the derived amino acid sequence of ZSA. This additional information allows us to discuss the results described here in the framework of the amino acid residues of both proteins involved in the formation of the enzyme-Inhibitor complex and to pinpoint the amino acids responsible for the specificity of the interaction.
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Protective mechanism of the Mexican bean weevil against high levels of alpha-Amylase Inhibitor in the common bean.
Plant Physiology, 1996Co-Authors: Masao Ishimoto, Maarten J. ChrispeelsAbstract:[alpha]-Amylase Inhibitor ([alpha]AI) protects seeds of the common bean (Phaseolus vulgaris) against predation by certain species of bruchids such as the cowpea weevil (Callosobruchus maculatus) and the azuki bean weevil (Callosobruchus chinensis), but not against predation by the bean weevil (Acanthoscelides obtectus) or the Mexican bean weevil (Zabrotes subfasciatus), insects that are common in the Americas. We characterized the interaction of [alpha]AI-1 present in seeds of the common bean, of a different isoform, [alpha]AI-2, present in seeds of wild common bean accessions, and of two homologs, [alpha]AI-Pa present in seeds of the tepary bean (Phaseolus acutifolius) and ([alpha]AI-Pc in seeds of the scarlet runner bean (Phaseolus coccineus), with the midgut extracts of several bruchids. The extract of the Z. subfasciatus larvae rapidly digests and inactivates [alpha]AI-1 and [alpha]AI-Pc, but not [alpha]AI-2 or [alphha]AI-Pa. The digestion is caused by a serine protease. A single proteolytic cleavage in the [beta] subunit of [alpha]AI-1 occurs at the active site of the protein. When degradation is prevented, [alpha]AI-1 and [alpha]AI-Pc do not inhibit the [alpha]-Amylase of Z. subfasciatus, although they are effective against the [alpha]-Amylase of C. chinensis. [alpha]AI-2 and [alpha]AI-Pa, on the other hand, do inhibit the [alpha]-Amylase of Z. subfasciatus, suggesting that they are good candidates for genetic engineering to achieve resistance to Z. subfasciatus.
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bruchid resistance of transgenic azuki bean expressing seed α Amylase Inhibitor of common bean
Entomologia Experimentalis Et Applicata, 1996Co-Authors: Masao Ishimoto, Maarten J. Chrispeels, Takashi Sato, Keisuke KitamuraAbstract:Various species of bruchid beetles including Callosobruchus chinensis, C. maculatus and C. analis cause post-harvest damage of azuki bean seeds, an important East Asian grain legume. The α-Amylase in the midguts of these insects is inhibited by the α-Amylase Inhibitor (αAI) present in common bean seeds. Transformation of azuki bean with the αAI gene driven by the promoter of phytohemagglutinin results in high levels of αAI in the seeds and the complete block of bruchid development on the seeds. Zabrotes subfasciatus, a South and Central American bruchid that is a storage pest of common bean, develops normally on the transgenic azuki bean.
You-liang Zheng - One of the best experts on this subject based on the ideXlab platform.
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phylogenetic analysis of the dimeric alpha Amylase Inhibitor sequences from an orthologous region in 21 different genomes of the tribe triticeae poaceae
Biochemical Systematics and Ecology, 2010Co-Authors: Ji-rui Wang, Ze-hong Yan, You-liang Zheng, Bernard R Baum, Xiujin Lan, Yu-ming WeiAbstract:Abstract Six hundred and thirty gene sequences from 21 different genomes in Triticeae tribe were obtained and subjected to phylogenetic analysis. The sequences showed high homology in both nucleotide sequences and length variation, and had a common conserved cysteine skeleton C–Xn–C–Xn–C–Xn–CC–Xn–C–X–C–Xn–C–Xn–C–Xn–C. The sequences from common wheat formed three clusters; two were close to Aegilops tauschii and Aegilops speltoides sequences, respectively, and the third cluster was complex with sequences from Ae. speltoides, Aegilops searsii, and Aegilops bicornis. Different S genome(s) of Aegilops contributed α-Amylase Inhibitor loci to polyploid wheat by gene introgression in interspecific hybridizations. No sequence from common wheat was similar to that from einkorn wheat. We conclude that the occurrence of multiple chromosomal translocations or inversions in the different genomes of Triticeae had not dramatically affected the primary structure of dimeric α-Amylase Inhibitors. The results revealed important information on genome shaping events and processes occurring at the dimeric α-Amylase Inhibitor genes loci and their bearing on the phylogenetic relationships in the tribe Triticeae (Poaceae).
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the impact of single nucleotide polymorphism in monomeric alpha Amylase Inhibitor genes from wild emmer wheat primarily from israel and golan
BMC Evolutionary Biology, 2010Co-Authors: Ji-rui Wang, Yu-ming Wei, Ze-hong Yan, Mei Deng, Eviatar Nevo, You-liang ZhengAbstract:Various enzyme Inhibitors act on key insect gut digestive hydrolases, including alpha-Amylases and proteinases. Alpha-Amylase Inhibitors have been widely investigated for their possible use in strengthening a plant's defense against insects that are highly dependent on starch as an energy source. We attempted to unravel the diversity of monomeric alpha-Amylase Inhibitor genes of Israeli and Golan Heights' wild emmer wheat with different ecological factors (e.g., geography, water, and temperature). Population methods that analyze the nature and frequency of allele diversity within a species and the codon analysis method (comparing patterns of synonymous and non-synonymous changes in protein coding sequences) were used to detect natural selection. Three hundred and forty-eight sequences encoding monomeric alpha-Amylase Inhibitors (WMAI) were obtained from 14 populations of wild emmer wheat. The frequency of SNPs in WMAI genes was 1 out of 16.3 bases, where 28 SNPs were detected in the coding sequence. The results of purifying and the positive selection hypothesis (p < 0.05) showed that the sequences of WMAI were contributed by both natural selection and co-evolution, which ensured conservation of protein function and inhibition against diverse insect Amylases. The majority of amino acid substitutions occurred at the C-terminal (positive selection domain), which ensured the stability of WMAI. SNPs in this gene could be classified into several categories associated with water, temperature, and geographic factors, respectively. Great diversity at the WMAI locus, both between and within populations, was detected in the populations of wild emmer wheat. It was revealed that WMAI were naturally selected for across populations by a ratio of dN/dS as expected. Ecological factors, singly or in combination, explained a significant proportion of the variations in the SNPs. A sharp genetic divergence over very short geographic distances compared to a small genetic divergence between large geographic distances also suggested that the SNPs were subjected to natural selection, and ecological factors had an important evolutionary role in polymorphisms at this locus. According to population and codon analysis, these results suggested that monomeric alpha-Amylase Inhibitors are adaptively selected under different environmental conditions.
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molecular evolution of dimeric α Amylase Inhibitor genes in wild emmer wheat and its ecological association
BMC Evolutionary Biology, 2008Co-Authors: Ji-rui Wang, Yu-ming Wei, Ze-hong Yan, You-liang Zheng, Eviatar Nevo, Xiangyu Long, Bernard R BaumAbstract:Background α-Amylase Inhibitors are attractive candidates for the control of seed weevils, as these insects are highly dependent on starch as an energy source. In this study, we aimed to reveal the structure and diversity of dimeric α-Amylase Inhibitor genes in wild emmer wheat from Israel and to elucidate the relationship between the emmer wheat genes and ecological factors using single nucleotide polymorphism (SNP) markers. Another objective of this study was to find out whether there were any correlations between SNPs in functional protein-coding genes and the environment.
Hartmut E Schroeder - One of the best experts on this subject based on the ideXlab platform.
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expression of the insecticidal bean α Amylase Inhibitor transgene has minimal detrimental effect on the nutritional value of peas fed to rats at 30 of the diet
Journal of Nutrition, 1999Co-Authors: Arpad Pusztai, Maarten J. Chrispeels, Grant G S Bardocz, Ruben Alonso, Hartmut E Schroeder, Linda Tabe, T J V HigginsAbstract:The effect of expression of bean alpha-Amylase Inhibitor (alpha-AI) transgene on the nutritional value of peas has been evaluated by pair-feeding rats diets containing transgenic or parent peas at 300 and 650 g/kg, respectively, and at 150 g protein/kg diet, supplemented with essential amino acids to target requirements. The results were also compared with the effects of diets containing lactalbumin with or without 0.9 or 2.0 mg bean alpha-AI, levels equivalent to those in transgenic pea diets. When 300 and 650 g peas/kg diet were fed, the daily intake of alpha-AI was 11.5 or 26.3 mg alpha-AI, respectively. At the 300 g/kg level, the nutritional value of the transgenic and parent line peas was not significantly different. The weight gain and tissue weights of rats fed either of the two pea diets were not significantly different from each other or from those of rats given the lactalbumin diet even when this was supplemented with 0.9 g alpha-AI/kg. The digestibilities of protein and dry matter of the pea diets were slightly but significantly lower than those of the lactalbumin diet, probably due to the presence of naturally occurring antinutrients in peas. The nutritional value of diets containing peas at the higher (650 g) inclusion level was less than that of the lactalbumin diet. However, the differences between transgenic and parent pea lines were small, possibly because neither the purified recombinant alpha-AI nor that in transgenic peas inhibited starch digestion in the rat small intestine in vivo to the same extent as did bean alpha-AI. This was the case even though both forms of alpha-AI equally inhibited alpha-Amylase in vitro. Thus, this short-term study indicated that transgenic peas expressing bean alpha-AI gene could be used in rat diets at 300 g/kg level without major harmful effects on their growth, metabolism and health, raising the possibility that transgenic peas may also be used at this level in the diet of farm animals.
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bean alpha Amylase Inhibitor confers resistance to the pea weevil bruchus pisorum in transgenic peas pisum sativum l
Plant Physiology, 1995Co-Authors: Hartmut E Schroeder, Maarten J. Chrispeels, Linda Tabe, Stephanie Gollasch, A D Moore, Stuart Craig, D C Hardie, Donald Spencer, T J V HigginsAbstract:Bruchid larvae cause major losses of grain legume crops through-out the world. Some bruchid species, such as the cowpea weevil and the azuki bean weevil, are pests that damage stored seeds. Others, such as the pea weevil (Bruchus pisorum), attack the crop growing in the field. We transferred the cDNA encoding the [alpha]-Amylase Inhibitor ([alpha]-AI) found in the seeds of the common bean (Phaseolus vulgaris) into pea (Pisum sativum) using Agrobacterium-mediated transformation. Expression was driven by the promoter of phytohemagglutinin, another bean seed protein. The [alpha]-Amylase Inhibitor gene was stably expressed in the transgenic pea seeds at least to the T5 seed generation, and [alpha]-AI accumulated in the seeds up to 3% of soluble protein. This level is somewhat higher than that normally found in beans, which contain 1 to 2% [alpha]-AI. In the T5 seed generation the development of pea weevil larvae was blocked at an early stage. Seed damage was minimal and seed yield was not significantly reduced in the transgenic plants. These results confirm the feasibility of protecting other grain legumes such as lentils, mungbean, groundnuts, and chickpeas against a variety of bruchids using the same approach. Although [alpha]-AI also inhibits human [alpha]-Amylase, cooked peas should not have a negative impact on human energy metabolism.
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transgenic pea seeds expressing the α Amylase Inhibitor of the common bean are resistant to bruchid beetles
Nature Biotechnology, 1994Co-Authors: Richard E Shade, T J V Higgins, Hartmut E Schroeder, Linda Tabe, José Javier Pueyo, Larry L Murdock, Maarten J. ChrispeelsAbstract:Infestations of stored legume seeds by bruchid beetles, such as the cowpea weevil and the Azuki bean weevil cause substantial economic and nutritional losses of these food crops, especially in developing countries. Seeds of the common bean are resistant to these bruchids largely because of the presence of α-Amylase Inhibitor (αAI-Pv), a seed protein that is toxic to the larvae. The αAI-Pv gene is therefore a candidate for a genetic engineering approach that would make other legumes (pea, chickpea, cowpea, Azuki bean) resistant to bruchid infestations. We tested this possibility by transforming peas (Pisum sativum) with the αAI-Pv gene driven by a strong seed-specific promoter. The levels of αAI protein in the pea seeds were as high as in bean seeds and the peas were resistant to the cowpea and Azuki bean weevils.
J E Campillo - One of the best experts on this subject based on the ideXlab platform.
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white bean Amylase Inhibitor administered orally reduces glycaemia in type 2 diabetic rats
British Journal of Nutrition, 2006Co-Authors: M A Tormo, I Gilexojo, Romero A De Tejada, J E CampilloAbstract:A purified pancreatic alpha-Amylase Inhibitor (alpha-AI) from white beans (Phaseolus vulgaris) was administered orally (100 mg/kg body weight dissolved in 9 g NaCl/l) for 22 d to non-diabetic (ND) and type 2 diabetic (neonatal diabetes models n0-STZ and n5-STZ) male Wistar rats. Mean glycaemia (mmol/l) declined from day 4 of the alpha-AI administration in ND rats (5.48 (sem 0.08) v. 4.39 (sem 0.13); P<0.05), n0-STZ diabetic rats (7.94 (sem 0.42) v. 5.56 (sem 0.32); P<0.01) and n5-STZ diabetic rats (17.34 (sem 2.58) v. 11.93 (sem 1.96)), until the end of treatment: ND (5.22 (sem 0.21) v. 3.97 (sem 0.06); P<0.01); n0-STZ (8.10 (sem 0.19) v. 5.21 (sem 0.30); P<0.01); and n5-STZ (16.36 (sem 2.14) v. 7.69 (sem 1.34); P<0.01). There was a decrease in water intake (ml/d) in the alpha-AI-treated diabetic rats: n0-STZ (30 (sem 0.10) v. 22 (sem 1.50); P<0.01) and n5-STZ (76 (sem 5.04) v. 57 (sem 4.85); P<0.01). Food intake (g/d) decreased in all three groups: ND (23 (sem 0.31) v. 20 (sem 0.03); P<0.05); n0-STZ (22 (sem 0.55) v. 16 (sem 0.98); P<0.01); and n5-STZ (31 (sem 0.58) v. 23 (sem 1.20); P<0.01). The enterocyte sucrase and maltase activities (U/g proteins) were high (P<0.01) in the untreated diabetic rats, n0-STZ (45 (sem 4) and 152 (sem 10), respectively) and n5-STZ (67 (sem 12) and 151 (sem 10), respectively) with respect to the ND rats (24 (sem 2) and 74 (sem 10), respectively). After alpha-AI treatment, enzyme activities declined in both diabetic rats, n0-STZ (21 (sem 2) and 85 (sem 11); P<0.01) and n5-STZ (28 (sem 7) and 75 (sem 19); P<0.05), to values close to those in the ND rats. In conclusion, alpha-AI significantly reduced glycaemia in both the ND and diabetic animals and reduced the intake of food and water, and normalized the elevated disaccharidase levels of the diabetic rats.
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hypoglycaemic and anorexigenic activities of an α Amylase Inhibitor from white kidney beans phaseolus vulgaris in wistar rats
British Journal of Nutrition, 2004Co-Authors: M A Tormo, I Gilexojo, Romero A De Tejada, J E CampilloAbstract:: An Inhibitor of alpha-Amylase was isolated and purified from an extract of white kidney beans (Phaseolus vulgaris). The acute oral administration of the Inhibitor (50 mg/kg body weight) to adult Wistar rats together with a starch load (2 g/kg body weight suspended in NaCl (9 g/l)) reduced the increase in glycaemia over the basal value (NaCl, 222 (SEM 49); Inhibitor, 145 (SEM 16) mmol/l x 180 min; P<0.05) without modifying the insulin response. On administering the Inhibitor orally (50 mg/kg body weight dissolved in NaCl (9 g/l)) for 21 d to rats fed on a standard diet, a decline was observed in the glycaemia values on day 0 (NaCl, 5.53 (SEM 0.12); Inhibitor, 5.25 (SEM 0.16) mmol/l) relative to those obtained on days 10 (NaCl, 5.00 (SEM 0.14); Inhibitor, 4.60 (SEM 0.08) mmol/l; P<0.05) and 21 (NaCl, 5.22 (SEM 0.22); Inhibitor, 4.50 (SEM 0.12) mmol/l; P<0.01) of treatment, without modifying the plasma concentration of insulin. There was found to be a significant anorexigenic action of the Inhibitor; there was reduced food intake (NaCl, 23.07 (SEM 0.31); Inhibitor, 19.50 (SEM 0.49) g/d; P<0.01), a reduced weight gain (NaCl, 52 (SEM 3); Inhibitor, -1.33 (SEM 8.9) g/21 d; P<0.01), as well as changes in the activity of some intestinal enzymes such as maltase (NaCl, 87 (SEM 7); Inhibitor, 127 (SEM 11) U/g proteins; P<0.05). The present study has shown, for the first time, that the prolonged administration of an alpha-Amylase Inhibitor reduces blood glucose levels and body-weight gain in Wistar rats.