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Microarchitecture of the tsetse fly proboscis
BACKGROUND: Tsetse flies (genus Glossina) are large blood-sucking dipteran flies that are important as vectors of human and animal trypanosomiasis in sub-Saharan Africa. Tsetse anatomy has been well described, including detailed accounts of the functional anatomy of the proboscis for piercing host s...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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BioMed Central
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5606065/ https://www.ncbi.nlm.nih.gov/pubmed/28927459 http://dx.doi.org/10.1186/s13071-017-2367-2 |
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author | Gibson, Wendy Peacock, Lori Hutchinson, Rachel |
author_facet | Gibson, Wendy Peacock, Lori Hutchinson, Rachel |
author_sort | Gibson, Wendy |
collection | PubMed |
description | BACKGROUND: Tsetse flies (genus Glossina) are large blood-sucking dipteran flies that are important as vectors of human and animal trypanosomiasis in sub-Saharan Africa. Tsetse anatomy has been well described, including detailed accounts of the functional anatomy of the proboscis for piercing host skin and sucking up blood. The proboscis also serves as the developmental site for the infective metacyclic stages of several species of pathogenic livestock trypanosomes that are inoculated into the host with fly saliva. To understand the physical environment in which these trypanosomes develop, we have re-examined the microarchitecture of the tsetse proboscis. RESULTS: We examined proboscises from male and female flies of Glossina pallidipes using light microscopy and scanning electron microscopy (SEM). Each proboscis was removed from the fly head and either examined intact or dissected into the three constituent components: Labrum, labium and hypopharynx. Our light and SEM images reaffirm earlier observations that the tsetse proboscis is a formidably armed weapon, well-adapted for piercing skin, and provide comparative data for G. pallidipes. In addition, the images reveal that the hypopharynx, the narrow tube that delivers saliva to the wound site, ends in a remarkably ornate and complex structure with around ten finger-like projections, each adorned with sucker-like protrusions, contradicting previous descriptions that show a simple, bevelled end like a hypodermic needle. The function of the finger-like projections is speculative; they appear to be flexible and may serve to protect the hypopharynx from influx of blood or microorganisms, or control the flow of saliva. Proboscises were examined after colonisation by Trypanosoma congolense savannah. Consistent with the idea that colonisation commences in the region nearest the foregut, the highest densities of trypanosomes were found in the region of the labrum proximal to the bulb, although high densities were also found in other regions of the labrum. Trypanosomes were visible through the thin wall of the hypopharynx by both light microscopy and SEM. CONCLUSIONS: We highlight the remarkable architecture of the tsetse proboscis, in particular the intricate structure of the distal end of the hypopharynx. Further work is needed to elucidate the function of this intriguing structure. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13071-017-2367-2) contains supplementary material, which is available to authorized users. |
format | Online Article Text |
id | pubmed-5606065 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-56060652017-09-20 Microarchitecture of the tsetse fly proboscis Gibson, Wendy Peacock, Lori Hutchinson, Rachel Parasit Vectors Research BACKGROUND: Tsetse flies (genus Glossina) are large blood-sucking dipteran flies that are important as vectors of human and animal trypanosomiasis in sub-Saharan Africa. Tsetse anatomy has been well described, including detailed accounts of the functional anatomy of the proboscis for piercing host skin and sucking up blood. The proboscis also serves as the developmental site for the infective metacyclic stages of several species of pathogenic livestock trypanosomes that are inoculated into the host with fly saliva. To understand the physical environment in which these trypanosomes develop, we have re-examined the microarchitecture of the tsetse proboscis. RESULTS: We examined proboscises from male and female flies of Glossina pallidipes using light microscopy and scanning electron microscopy (SEM). Each proboscis was removed from the fly head and either examined intact or dissected into the three constituent components: Labrum, labium and hypopharynx. Our light and SEM images reaffirm earlier observations that the tsetse proboscis is a formidably armed weapon, well-adapted for piercing skin, and provide comparative data for G. pallidipes. In addition, the images reveal that the hypopharynx, the narrow tube that delivers saliva to the wound site, ends in a remarkably ornate and complex structure with around ten finger-like projections, each adorned with sucker-like protrusions, contradicting previous descriptions that show a simple, bevelled end like a hypodermic needle. The function of the finger-like projections is speculative; they appear to be flexible and may serve to protect the hypopharynx from influx of blood or microorganisms, or control the flow of saliva. Proboscises were examined after colonisation by Trypanosoma congolense savannah. Consistent with the idea that colonisation commences in the region nearest the foregut, the highest densities of trypanosomes were found in the region of the labrum proximal to the bulb, although high densities were also found in other regions of the labrum. Trypanosomes were visible through the thin wall of the hypopharynx by both light microscopy and SEM. CONCLUSIONS: We highlight the remarkable architecture of the tsetse proboscis, in particular the intricate structure of the distal end of the hypopharynx. Further work is needed to elucidate the function of this intriguing structure. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13071-017-2367-2) contains supplementary material, which is available to authorized users. BioMed Central 2017-09-19 /pmc/articles/PMC5606065/ /pubmed/28927459 http://dx.doi.org/10.1186/s13071-017-2367-2 Text en © The Author(s). 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. |
spellingShingle | Research Gibson, Wendy Peacock, Lori Hutchinson, Rachel Microarchitecture of the tsetse fly proboscis |
title | Microarchitecture of the tsetse fly proboscis |
title_full | Microarchitecture of the tsetse fly proboscis |
title_fullStr | Microarchitecture of the tsetse fly proboscis |
title_full_unstemmed | Microarchitecture of the tsetse fly proboscis |
title_short | Microarchitecture of the tsetse fly proboscis |
title_sort | microarchitecture of the tsetse fly proboscis |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5606065/ https://www.ncbi.nlm.nih.gov/pubmed/28927459 http://dx.doi.org/10.1186/s13071-017-2367-2 |
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