An immunocytochemical investigation of trypsin secretion in the midgut of the stablefly, Stomoxys calcitrans

Jordão, Beatriz P.; Lehane, Michael J.; Terra, Walter R.; Ribeiro, Alberto F.; Ferreira, Clélia

doi:10.1016/0965-1748(95)00112-3

Cited by 36 publications

(12 citation statements)

References 44 publications

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“…Anti-Gram-negative activity is restricted to the anterior midgut, which is the region where peritrophic matrix is produced (21) and where blood is stored and dehydrated (22) before the addition of digestive enzymes from more posterior regions of the midgut where digestion and absorption occur (21,(23)(24)(25)(26). Undigested blood, which may be stored for up to 48 hr in this region, is a potentially rich medium for bacterial growth.…”

Section: Discussionmentioning

confidence: 99%

Midgut-specific immune molecules are produced by the blood-sucking insect Stomoxys calcitrans

Lehane

1997

Proc. Natl. Acad. Sci. U.S.A.

132

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We have cloned and sequenced two defensins, Smd1 and Smd2, from anterior midgut tissue of the bloodsucking f ly Stomoxys calcitrans. The DNA and N-terminal protein sequences suggest both are produced as prepropeptides. Smd1 differs from the classic defensin pattern in having an unusual six-amino acid-long N-terminal sequence. Both Smd1 and Smd2 have lower pI points and charge than insect defensins derived from fat body͞hemocytes. Northern analysis shows both of these defensin molecules are tissue specific; both are produced by the anterior midgut tissue and, unlike the other insect defensins reported to date, neither appears to be expressed in fat body or hemocytes. Northern analysis also shows that mRNAs for both defensins are constitutively produced in the anterior midgut tissues and that these transcripts are up-regulated in response to sterile as well as a lipopolysaccharide-containing blood meal. However, antiGram-negative biological activity in the midgut is substantially enhanced by lipopolysaccharide. These findings suggest that the insect midgut has its own tissue-specific immune mechanisms and that this invertebrate epithelium is, like several vertebrate epithelia, protected by specific antibacterial peptides.

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Section: Discussionmentioning

confidence: 99%

Midgut-specific immune molecules are produced by the blood-sucking insect Stomoxys calcitrans

Lehane

1997

Proc. Natl. Acad. Sci. U.S.A.

132

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“…After the run, the gel was removed and washed with 2.5% (v/v) Triton X-100 in 100 mM Tris-HCl buffer pH 8.5. After this step, the gel slab was layered onto a 4.5% polyacrylamide gel slab containing 1% gelatin and left for 2 h at 30 1C, essentially as described by Jorda˜o et al (1996). Finally, the original gel slab was removed and the gelatincontaining gel slab was stained with 0.1% (w/v) Coomassie Blue R-250 in water-ethanol-acetic acid (5:5:2 by volume) for at least 6 h. Distaining was accomplished in ethanolacetic acid-water (30:7:63 by volume) until clear bands could be visualized against a dark blue background.…”

Section: In Gel Assaysmentioning

confidence: 99%

Substrate specificity of insect trypsins and the role of their subsites in catalysis

Lopes

Juliano

Marana

et al. 2006

Insect Biochemistry and Molecular Biology

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“…, 1995). The opaque zone cells are found to contain many vesicles where the digestive enzymes are stored as zymogens and are released quickly to the gut lumen in response to the blood meal (Jordao et al. , 1996).…”

Section: Introductionmentioning

confidence: 99%

“…In Stomoxys , the regulation of digestive enzymes have been shown to be at the posttranscriptional level with protein levels reaching a maximum shortly after obtaining the blood meal (8 -10 h) (Mofatt et al , 1995). The opaque zone cells are found to contain many vesicles where the digestive enzymes are stored as zymogens and are released quickly to the gut lumen in response to the blood meal (Jordao et al , 1996). Two gut-specific cDNA products have been molecularly characterized from Stomoxys ( Ssp1 and Ssp2 ) and both are found to contain serine protease motifs with chymotrypsin and trypsin specificities, respectively (Lehane et al , 1998).…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of two serine proteases expressed in gut tissue of the African trypanosome vector, Glossina morsitans morsitans

Jiang

Cheng

et al. 2001

Insect Molecular Biology

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Serine proteases are major insect gut enzymes involved in digestion of dietary proteins, and in addition they have been implicated in the process of pathogen establishment in several vector insects. The medically important vector, tsetse fly (Diptera:Glossinidiae), is involved in the transmission of African trypanosomes, which cause devastating diseases in animals and humans. Both the male and female tsetse can transmit trypanosomes and both are strict bloodfeeders throughout all stages of their development. Here, we describe the characterization of two putative serine protease-encoding genes, Glossina serine protease-1 (Gsp1) and Glossina serine protease-2 (Gsp2) from gut tissue. Both putative cDNA products represent prepro peptides with hydrophobic signal peptide sequences associated with their 5'-end terminus. The Gsp1 cDNA encodes a putative mature protein of 245 amino acids with a molecular mass of 26 428 Da, while the predicted size of the 228 amino acid mature peptide encoded by Gsp2 cDNA is 24 573 Da. Both deduced peptides contain the Asp/His/Ser catalytic triad and the conserved residues surrounding it which are characteristic of serine proteases. In addition, both proteins have the six-conserved cysteine residues to form the three-cysteine bonds typically present in invertebrate serine proteases. Based on the presence of substrate specific residues, the Gsp1 gene encodes a chymotrypsin-like protease while Gsp2 gene encodes for a protein with trypsin-like activity. Both proteins are encoded by few loci in tsetse genome, being present in one or two copies only. The mRNA expression levels for the genes do not vary extensively throughout the digestive cycle, and high levels of mRNAs can be readily detected in the gut tissue of newly emerged flies. The levels of trypsin and chymotrypsin activities in the gut lumen increase following blood feeding and change significantly in the gut cells throughout the digestion cycle. Hence, the regulation of expression for trypsin and chymotrypsin occurs at the post-transcriptional level in tsetse. Both the coding sequences and patterns of expression of Gsp1 and Gsp2 genes are similar to the serine proteases that have been reported from the bloodfeeding insect Stomoxys calcitrans.

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An immunocytochemical investigation of trypsin secretion in the midgut of the stablefly, Stomoxys calcitrans

Cited by 36 publications

References 44 publications

Midgut-specific immune molecules are produced by the blood-sucking insect Stomoxys calcitrans

Midgut-specific immune molecules are produced by the blood-sucking insect Stomoxys calcitrans

Substrate specificity of insect trypsins and the role of their subsites in catalysis

Molecular characterization of two serine proteases expressed in gut tissue of the African trypanosome vector, Glossina morsitans morsitans

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