Digestive enzymes

Terra, Walter R.; Ferreira, Clélia; Jordão, Beatriz P.; Dillon, Rod J.

doi:10.1007/978-94-009-1519-0_6

Cited by 164 publications

(185 citation statements)

References 113 publications

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“…Surprisingly, intact bovine fetuin did not induce stem cell differentiation, although its hydrolysate was quite potent. Mixed midgut cell cultures and intact midgut epithelium contain differentiated columnar cells that are rich in trypsins, chymotrypsins, elastases, carboxypeptidases, and dipeptidases (Terra et al, 1996). Many of these enzymes are located on columnar cell microvilli, which may break off into the culture medium just as they are normally released into the gut lumen in vivo (Billingsley and Lehane, 1996), and may provide the enzymes necessary to hydrolyze fetuin from the culture medium to MDF1 in vitro.…”

Section: Midgut Differentiating Factors (Mdfs) 1 and 2: Separation Anmentioning

confidence: 99%

Factors affecting proliferation and differentiation of lepidopteran midgut stem cells

Loeb

2010

Arch Insect Biochem Physiol

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Midgut stem cells of last instar larvae and pupae of Heliothis virescens, Lymantria dispar and several other Lepidopteran species have been cultured in vitro and have been induced to proliferate using low titers of ecdysteroids and the 77-Kda peptide fragment, a-arylphorin, isolated and identified from pupal fat body tissue. The insulin-related hormone, Bombyxin, also induced mitosis in cultured midgut stem cells; it appeared to be fast-acting and quickly inactivated, while a-arylphorin was slower to act and had a longer lasting effect in vitro, indicating different functions for these proliferation agents. Changes in Calcium ion concentration within or outside the cells discretely affected stem cell differentiation, indicating a role for second messenger participation in peptide regulation of this process. Four different peptides (MDFs 1-4) that induced midgut stem cells to differentiate to mature midgut cell types in vitro were isolated and characterized from conditioned media and hemolymph of H. virescens and L. dispar. However, platelet-derived growth factor (PDGF), epidermal growth factor (EGF), and all-trans retinoic acid (RA) from vertebrate sources induced differentiation to nonmidgut cell types as well. MDF1 was located in basal areas of columnar cells of midgut epithelium, although MDF2 was observed in all of the cytoplasm of columnar cells and in droplets of antibody positive material in the midgut lumen, suggesting a digestive function as well for this Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the USDA and does not imply its approval to the exclusion of other products that may also be suitable. Correspondence to: Marcia J. Loeb, 6920 Fairfax Rd.,

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Section: Midgut Differentiating Factors (Mdfs) 1 and 2: Separation Anmentioning

confidence: 99%

Factors affecting proliferation and differentiation of lepidopteran midgut stem cells

Loeb

2010

Arch Insect Biochem Physiol

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“…It converts starch to maltose, which is then hydrolyzed to glucose by an α-glucosidase. In insects only α-amylases has been found to hydrolyze long α-1,4-glucan chains such as starch or glycogen [33] . Amylase activity has been described from several insect orders including Coleoptera, Hymenoptera, Diptra, Lepidoptera and Hemiptera [4,25,31,23,34] .…”

Section: Generamentioning

confidence: 99%

“…Amylases in insect are generally most active in the neutral to slightly acid pH condition [2,33] . Optimal pH values for amylases in larvae of several coleopterans were 4-5.8 [2] and in Lygus spp.…”

Section: Effect Of Ph and Temperature On Enzyme Activitymentioning

confidence: 99%

“…Inhibitors and activators used were chosen for comparison with reported values [2,33,35,24] that NaCl activated the enzyme. Similarly, in Lygus hesperus Knight and L. lineolaris (Palisot de Beauvois), α-amylases were activated by NaCl [1,34] ).…”

Section: Effect Of Ph and Temperature On Enzyme Activitymentioning

confidence: 99%

“…Cohen and Hendrix (1994) found that some homopterans' α-amylase is also Cl -activated [13] . Amylase activation by Cl -is characteristic has been reported in many mammals and bacteria [29,33] , nematodes [23] , as well as other insects [33] . However, the amylases in some insect species, e.g., Callosobruchus chinensis (Linaeus) (Coleoptera: Bruchidae), Bombyx mori (Linnaeus) (Lepidoptera: Bombycidae), are inhibited by Cl − [33] .…”

Section: Effect Of Ph and Temperature On Enzyme Activitymentioning

confidence: 99%

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Assessing of α-Amylase Activity of Midgut in Wheat Bug Eurygaster maura

Mehrabadi¹,

Bandani²

2009

American J. of Applied Sciences

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Abstract:To determine of α-amylase activity in the midgut of Eurygaster maura, some of adult insect was collected and their gut isolated and characterized. Enzyme samples from midguts of adults were prepared by the method of Cohen with slight modifications. α-Amylase activity was assayed based on Bernfeld method by the dinitrosalicylic acid (DNS) procedure. The activity of α-amylase in midgut was 0.083 U/insect. The optimum pH and temperature for the enzyme activity was determined to be 6-6.5 and 30-35ºC, respectively. The enzyme activity was inhibited by addition of EDTA (Ethylenediamine tetraacetic acid) urea, CaCl2, MgCl2 and SDS but Mg 2+ , NaCl and KCl enhanced enzyme activity.

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Two polypeptide factors that promote differentiation of insect midgut stem cells in vitro

Loeb

Jaffe

Gelman

et al. 1999

Arch. Insect Biochem. Physiol.

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Isolated stem cells from the midguts of Manduca sexta and Heliothis virescens can be induced to differentiate in vitro by either of two polypeptide factors. One of the peptides was isolated from culture medium conditioned by differentiating mixed midgut cells; we used high performance liquid chromatographic separation and Edman degradation of the most prominent active peak. It is a polypeptide with 30 amino acid residues (3,244 Da), with the sequence HVGKTPIVGQPSIPGGPVRLCPGRIRYFKI, and is identical to the C‐terminal peptide of bovine fetuin. A portion of this molecule (HVGKTPIVGQPSIPGGPVRLCPGRIR) was synthesized and was found to be very active in inducing differentiation of H. Virescens midgut stem cells. It was designated Midgut Differentiation Factor 1 (MDF1). Proteolysis of bovine fetuin with chymotrypsin allowed isolation of a pentamer, Midgut Differentiation Factor 2 (MDF2) with the sequence HRAHY corresponding to a portion of the fetuin molecule near MDF1. Synthetic MDF2 was also biologically active in midgut stem cell bioassays. Dose response curves indicate activity in physiological ranges from 10–14 to 10–9 M for MDF1 and 10–15 to 10–5 M for MDF2. Arch. Insect Biochem. Physiol. 40:129–140, 1999. Published 1999 Wiley‐Liss, Inc. This article is a US Government work and, as such, is in the public domain in the United States of America.

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Digestive enzymes

Cited by 164 publications

References 113 publications

Factors affecting proliferation and differentiation of lepidopteran midgut stem cells

Factors affecting proliferation and differentiation of lepidopteran midgut stem cells

Assessing of α-Amylase Activity of Midgut in Wheat Bug Eurygaster maura

Two polypeptide factors that promote differentiation of insect midgut stem cells in vitro

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