Structure and ultrastructure of the insect midgut

Billingsley, Peter F.; Lehane, Michael J.

doi:10.1007/978-94-009-1519-0_1

Cited by 104 publications

(120 citation statements)

References 71 publications

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“…Flies used for HPLC purification of midgut AMPs were fed from cotton wool soaked swabs on either pig blood or casein hydrolysate (20 g/100 ml). At 24 -36 h after feeding, anterior midguts (2,000 consisting of proventriculus, thoracic, and reservoir regions) (19) were dissected in 154 mM NaCl and homogenized at 4°C in 200 mM sodium acetate at pH 4.5. The homogenate was heated to 100°C for 5 min and centrifuged at 12,000 ϫ g for 10 min at 4°C.…”

Section: Insect and Tissue Preparationmentioning

confidence: 99%

Epithelial Innate Immunity

Boulanger¹,

Munks²,

Hamilton³

et al. 2002

Journal of Biological Chemistry

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The gut epithelium is an essential interface in insects that transmit parasites. We investigated the role that local innate immunity might have on vector competence, taking Stomoxys calcitrans as a model. S. calcitrans is sympatric with tsetse flies, feeds on many of the same vertebrate hosts, and is thus regularly exposed to the trypanosomes that cause African sleeping sickness and nagana. Despite this, S. calcitrans is not a cyclical vector of these trypanosomes. Trypanosomes develop exclusively in the lumen of digestive organs, and so epithelial immune mechanisms, and in particular antimicrobial peptides (AMPs), may be the prime determinants of the fate of an infection. To investigate why S. calcitrans is not a cyclical vector of trypanosomes, we have looked in its midgut for AMPs with trypanolytic activity. We have identified a new AMP of 42 amino acids, which we named stomoxyn, constitutively expressed and secreted exclusively in the anterior midgut of S. calcitrans. It displays an amphipathic helical structure and exhibits a broad activity spectrum affecting the growth of microorganisms. Interestingly, this AMP exhibits trypanolytic activity to Trypanosoma brucei rhodesiense. We argue that stomoxyn may help to explain why S. calcitrans is not a vector of trypanosomes causing African sleeping sickness and nagana.Epithelial intestinal innate immunity plays a major role in the control of infectious diseases in vertebrates (1, 2). In invertebrates, data are still fragmentary despite gut epithelium being an essential interface for parasites during their development in insect vectors. Understanding vector biology is a key element in the control of many parasitic diseases. In this context, the comparison of the trypanosome vector Glossina with the sympatric but non-vector Stomoxys calcitrans is particularly interesting. The tsetse fly Glossina spp. is the major vector of the range of trypanosomes that cause African sleeping sickness in humans and nagana in livestock. Stable flies, Stomoxys spp., feed on the same vertebrate hosts as tsetse flies and have a very similar digestive physiology and midgut anatomy. Although Stomoxys is constantly exposed to trypanosomes, it kills them in the midgut within 2-4 days of ingestion (3). So Stomoxys is not a cyclical vector of trypanosomes (although it can act as a mechanical vector, "flying pin"). Why Stomoxys is not a cyclical vector of trypanosomes is unknown. Recent studies have shown that the insect immune system plays a determinant role in the fate of trypanosome infections in tsetse flies (4, 5). Consequently, in this report, we address the possibility that the distinction in vectorial capacity between Glossina and Stomoxys may lie in differences in immune mechanisms.Trypanosoma vivax matures entirely in the mouthparts of Glossina. The other trypanosomes causing nagana and human disease are ingested into the fly midgut where they multiply first in the endoperitrophic space and later in the ectoperitrophic space tightly sandwiched between the peritrophic matrix and the ...

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Section: Insect and Tissue Preparationmentioning

confidence: 99%

Epithelial Innate Immunity

Boulanger¹,

Munks²,

Hamilton³

et al. 2002

Journal of Biological Chemistry

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“…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. Cultures enriched in stem cells contain few columnar cells and probably lack enough of the proteases needed to liberate MDFs from fetuin into the medium.…”

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

confidence: 99%

“…The midgut is second in size to the epidermis of lepidopteran larvae, and is the major site for food digestion, transport of nutrients, and regulation of ion balance (Billingsley and Lehane, 1996). Bacteria, viruses, and toxins may accompany ingested food and water, making the midgut an organ of interest to researchers in insect control as well as insect development.…”

Section: Introductionmentioning

confidence: 99%

“…Intermolt midgut epithelium consists of columnar and goblet cells with a smattering of endocrine and stem cells, arranged in a pattern characteristic for each species (Billingsley and Lehane, 1996). Columnar cells are believed to function primarily in digestion and transport of nutrients, while goblet cells serve as ionic regulators (Billingsley and Lehane, 1996).…”

Section: Introductionmentioning

confidence: 99%

“…Columnar cells are believed to function primarily in digestion and transport of nutrients, while goblet cells serve as ionic regulators (Billingsley and Lehane, 1996).…”

Section: Introductionmentioning

confidence: 99%

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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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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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Structure and ultrastructure of the insect midgut

Cited by 104 publications

References 71 publications

Epithelial Innate Immunity

Epithelial Innate Immunity

Factors affecting proliferation and differentiation of lepidopteran midgut stem cells

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

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