Penetration and migration routes of Schistosoma japonicum miracidia in the snail Oncomelania hupensis

Parasitology ◽  
1991 ◽  
Vol 103 (1) ◽  
pp. 77-83 ◽  
Author(s):  
M. Y. Xia ◽  
J. Jourdane
Keyword(s):  
Spatial Distribution ◽  
Schistosoma Japonicum ◽  
Histological Study ◽  
Circulatory System ◽  
Selective Advantage ◽  
Oncomelania Hupensis ◽  
Migration Routes ◽  
Branchial Cavity ◽  
And Migration ◽  
Host Parasite

The routes of penetration and the strategies of invasion of Schistosoma japonicum miracidia in the snail vector Oncomelania hupensis were observed in a histological study. In all species of the genus Schistosoma, it is usually assumed that the miracidia achieve penetration through the tegument. Our results showed that at least 57% of S. japonicum miracidia penetrated the snail by natural openings (branchial cavity, mouth and rectum). Throughout the invasion phase, the larvae were observed in all the tissues and organs with the exception of the genital gland. The spatial distribution of parasites in the snail revealed that the migration towards the visceral organs such as the kidney, heart and sinuses (which are the most usual microhabitats of the mother sporocysts of S. japonicum) appeared to take place via the circulatory system. Using natural openings as routes for penetration probably provides a selective advantage in a host–parasite system in which the target mollusc is amphibious: we presume that the miracidia inside these natural openings are protected against desiccation when the snail leaves the water, and that they can subsequently invade the tissues.

scholarly journals Cryptic speciation in the Warbling Vireo (Vireo gilvus)

The Auk ◽  
2021 ◽  
Author(s):  
Scott F Lovell ◽  
M Ross Lein ◽  
Sean M Rogers
Keyword(s):  
Contact Zone ◽  
Nuclear Dna ◽  
Biological Species ◽  
Valid Species ◽  
Migration Routes ◽  
Dna Evidence ◽  
Show Evidence ◽  
And Migration ◽  
Surrounding Areas ◽  
Taxonomic Groups

Abstract Eastern (Vireo gilvus gilvus) and western (V. g. swainsoni) forms of the Warbling Vireo have essentially allopatric breeding ranges across north-central North America, but come into contact in central Alberta, Canada. In 1986, Jon Barlow presented preliminary morphological and song evidence suggesting that the Warbling Vireo complex might comprise more than one valid species. However, to date, Barlow’s suggestion is supported by only limited DNA evidence, demonstration of molt and migration differences between the taxa, and anecdotal accounts of differences in song, morphology, plumage, and ecology. We analyzed variation in both mitochondrial and nuclear DNA in birds from Alberta and surrounding areas to determine the levels of genetic differentiation and hybridization occurring in the contact zone, and whether the two taxa warrant recognition as separate biological species. Our analyses reveal that Warbling Vireos in Alberta and the surrounding areas are separated into two well-defined, genetically differentiated, and monophyletic clades corresponding to previously recognized taxonomic groups. The two taxa come into contact in a narrow (~85 km) zone in Barrhead County, northwest of Edmonton, Alberta. They show evidence of limited hybridization. The distinct genetic differences are maintained in the contact zone, where individuals of the two taxa may occupy neighboring territories. Differences in spring arrival dates, molt schedules, and migration routes indicate that a migratory divide may play an important role in reproductive isolation. We suggest that the two taxa are distinct cryptic species: an eastern form, Vireo gilvus, and a western form, Vireo swainsoni.

Morphology and activities of cell populations of haemocytes in Oncomelania hupensis following Schistosoma japonicum infection

2021 ◽  
Vol 181 ◽  
pp. 107590
Author(s):  
Yan Zhang ◽  
Sha Xu ◽  
Ni Jiang ◽  
Hongbin Tang ◽  
Huifen Dong ◽  
...  
Keyword(s):  
Schistosoma Japonicum ◽  
Cell Populations ◽  
Oncomelania Hupensis

Identification of Toll-like receptor family members in Oncomelania hupensis and their role in defense against Schistosoma japonicum

Acta Tropica ◽  
2018 ◽  
Vol 181 ◽  
pp. 69-78 ◽  
Author(s):  
Qin Ping Zhao ◽  
Qian Gao ◽  
Yan Zhang ◽  
Yan Wei Li ◽  
Wen Ling Huang ◽  
...  
Keyword(s):  
Schistosoma Japonicum ◽  
Family Members ◽  
Toll Like Receptor ◽  
Oncomelania Hupensis ◽  
Receptor Family

scholarly journals Revised distribution and phytosociological data of Orobanche coerulescens Stephan in Willd. (Orobanchaceae): Poland in relation to Central Europe

2012 ◽  
Vol 26 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Renata Piwowarczyk
Keyword(s):  
Eastern Europe ◽  
Central Europe ◽  
Plant Communities ◽  
Field Research ◽  
Range Limits ◽  
Migration Routes ◽  
Original Field ◽  
Critical Revision ◽  
And Migration ◽  
North Western

Abstract Orobanche coerulescens has a Eurasian distribution. The species is classified as extinct at most of its localities at the western limit of its range. Its populations are very scarce and critically endangered in Central Europe. This work presents the current distribution of O.coerulescens in Poland, based on a critical revision of herbarium and literature data as well as results of original field research, and reviews its distribution in Central Europe (partly in Eastern Europe). Habitats, plant communities, and migration routes of O.coerulescens in Central Europe are discussed. The species was initially known in Poland from now historical localities in Pomerania and the valley of the lower Vistula. In 2000-2011 it was recorded at 9 localities in Podlasie, the Małopolska Upland (Wyżyna Małopolska), and the Łódź Hills (Wzniesienia Łódzkie). Its abundance at the localities ranged from a few to over 1000 shoots. These are the largest populations of O.coerulescens at its western and north-western range limits.

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