A new second intermediate host and phylogenetic relationships based on the ITS2 sequence of Isoparorchis sp. (Digenea: Isoparorchiidae) in Thailand

2021 ◽  
Vol 95 ◽  
Author(s):  
P. Jaruboonyakorn ◽  
T. Chontananarth

Abstract The genus Isoparorchis (Family: Isoparorchiidae) contains trematodes infecting the air bladder of freshwater catfishes in Asia and Australia. Isoparorchis spp. rely on freshwater shrimps and fishes as intermediate hosts. There is limited information about parasitic infections in freshwater shrimp in Thailand, and Isoparorchis infection in an intermediate host in this country has never been reported. Thus, this study reports infections in freshwater shrimp (Macrobrachium lanchesteri and Caridina sp.), including overall prevalence, mean intensity, morphological characters and molecular analyses. The parasite specimens were analysed by studying their morphological characters, together with a molecular approach based on internal transcribed spacer 2 (ITS2) sequence data. The overall prevalence and mean intensity of Isoparorchis infections were 92% and 1.89, respectively. The metacercariae were identified as Isoparorchis sp. based on their morphological characters and supported by the comparison with published ITS2 sequences of Isoparorchis species. The phylogenetic studies based on the ITS2 region demonstrated that all of the Isoparorchis sp. specimens in this study are distinct from Isoparorchis species in previous reports. Moreover, we show for the first time that the freshwater shrimp M. lanchesteri serves as a second intermediate host of Isoparorchis sp. and we provide a morphological description and molecular characterization of Isoparorchis sp. metacercariae based on ITS2 sequence data to clarify the status of Isoparorchis sp. in Thailand.

Phytotaxa ◽  
2020 ◽  
Vol 441 (1) ◽  
pp. 47-59
Author(s):  
JIN-FEN HAN ◽  
FANG-RU NAN ◽  
JIA FENG ◽  
JUN-PING LV ◽  
QI LIU ◽  
...  

Four putative “Chantransia” isolates were collected from four locations in Hubei and Yunnan Provinces, China. Morphological analyses were conducted on all isolates. Two specimens (HB26 and YN2) fit the morphological description of A. pygmaea, while the other two isolates (YN1 and YN3) varied in morphology, but were within the circumscription of Audouinella hermannii. Due to the fact that the morphological characters of the “Chantransia” stages of order Batrachospermales and the species of genus Audouinella are too similar to be distinguished, a molecular analysis was performed to clarify the phylogenetic position of these four isolates based on rbcL and psbA sequences. Two “pygmaea” specimens collected from Jiugong Mountain, Hubei Province (HB26) and Shimen Gorge, Yunnan Province (YN2), such as S. jiugongshanensis and S. shimenxiaensis, are proposed primarily based on the DNA sequence data generated in this study. The description of these two new species provides more molecular data for phylogenetic analysis of the genus Sheathia. In addition to these newly described species, the results strongly support that those “hermannii” isolates (YN1 and YN3) collected from Yunnan Province were the “Chantransia” of S. arcuata. However, their gametophyte stages have not been found, meaning that critical diagnostic morphological features were unavailable and molecular methods were the only means for ascertaining their phylogenetic position. Considering the extensive application of the rbcL and psbA genes in phylogenetic analyses of freshwater red algae, we recommend using these two genes to identify species when no morphological characteristics are available.


1979 ◽  
Vol 53 (1) ◽  
pp. 79-89 ◽  
Author(s):  
Elisabeth van den Broek ◽  
Nienke de Jong

ABSTRACTAspects of the life cycle of Asymphylodora tincae have been studied in a small lake near Amsterdam. Bithynia tentaculata, being the only snail species that was very numerous in the lake, was the first as well as the main second intermediate host; adult trematodes were found exclusively in the tench, Tinca tinca. A small part of the cercariae that penetrate into B. tentaculata was able to develop into progenetic specimens. A morphological description is given of the following stages of A. tincae: adult, egg, redia, cercariaeum, metacercaria and progenetic stage. The cercariaeum is identified as Cercariaeum paludinae impurae De Filippi, 1854.It is concluded that A. tincae is a species, capable of large variation regarding both morphological structure (e.g. body spination, size) and life cycle.


2017 ◽  
Vol 5 (2) ◽  
Author(s):  
J. Chalwe ◽  
P. Adebola ◽  
M. Pillay

Sweetpotato (Ipomoea batatas) an economically important food crop is affected by viral and fungal diseases. The most important fungal disease is Alternaria blight caused by Alternaria bataticola. Alternaria blight can be controlled using fungicides and cultural practices in the short-term. A sustainable control measure is the development of resistant sweetpotato cultivars. A prerequisite to this approach is the knowledge of the genetic diversity of this fungal pathogen. This study assessed the genetic diversity of A. bataticola in South Africa using RAPD analysis, DNA sequencing and secondary structures of the ITS2 region. Samples were collected from 25 different localities and the pathogen was identified in the laboratory. Both RAPD and ITS2 sequence data showed that there is high levels of genetic diversity among the isolates of A. bataticola. Although the dendrograms generated from the RAPD and ITS2 sequences clustered some isolates according to their place of origin, the majority of isolates did not group according to their geographic origins. The predicted ITS2 secondary structure models were variable ranging from simple to complex. The unique secondary structures of each isolate can be used to identify and distinguish each of the isolates used in this study.  


2010 ◽  
Vol 42 (4) ◽  
pp. 405-421 ◽  
Author(s):  
James C. LENDEMER ◽  
Brendan P. HODKINSON

AbstractIn North America the names Punctelia subrudecta and P. perreticulata have variously been applied to corticolous sorediate Punctelia specimens with lecanoric acid and a pale lower surface. ITS1, 5.8S, and ITS2 sequence data were generated from a geographically and morphologically broad sampling from within these specimens, and a molecular phylogeny was inferred. A combined approach using morphology, geography, and phylogeny was used to circumscribe three distinct species in North America, one of which is described as new to science (P. caseana), one of which is finally confirmed for the continent (P. jeckeri), and one whose original circumscription is validated (P. perreticulata). The phylogeny inferred from ITS sequence data supports the taxonomic value of the following morphological characters for distinguishing species in this group: presence/absence of pruina; conidium type and length (although see discussion of P. jeckeri), and presence/absence of scrobiculae on the upper surface. A key to the North American species of Punctelia is provided.


2021 ◽  
Vol 9 (3) ◽  
pp. 666
Author(s):  
Niccolò Forin ◽  
Alfredo Vizzini ◽  
Federico Fainelli ◽  
Enrico Ercole ◽  
Barbara Baldan

In a recent monograph on the genus Rosellinia, type specimens worldwide were revised and re-classified using a morphological approach. Among them, some came from Pier Andrea Saccardo’s fungarium stored in the Herbarium of the Padova Botanical Garden. In this work, we taxonomically re-examine via a morphological and molecular approach nine different Roselliniasensu Saccardo types. ITS1 and/or ITS2 sequences were successfully obtained applying Illumina MiSeq technology and phylogenetic analyses were carried out in order to elucidate their current taxonomic position. Only the ITS1 sequence was recovered for Rosellinia areolata, while for R. geophila, only the ITS2 sequence was recovered. We proposed here new combinations for Rosellinia chordicola, R. geophila and R. horridula, while for R. ambigua, R. areolata, R. australis, R. romana and R. somala, we did not suggest taxonomic changes compared to the current ones. The name Rosellinia subsimilis Sacc. is invalid, as it is a later homonym of R. subsimilis P. Karst. & Starbäck. Therefore, we introduced Coniochaeta dakotensis as a nomen novum for R. subsimilis Sacc. This is the first time that these types have been subjected to a molecular study. Our results demonstrate that old types are an important source of DNA sequence data for taxonomic re-examinations.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ewa Pyrka ◽  
Gerard Kanarek ◽  
Grzegorz Zaleśny ◽  
Joanna Hildebrand

Abstract Background Leeches (Hirudinida) play a significant role as intermediate hosts in the circulation of trematodes in the aquatic environment. However, species richness and the molecular diversity and phylogeny of larval stages of strigeid trematodes (tetracotyle) occurring in this group of aquatic invertebrates remain poorly understood. Here, we report our use of recently obtained sequences of several molecular markers to analyse some aspects of the ecology, taxonomy and phylogeny of the genera Australapatemon and Cotylurus, which utilise leeches as intermediate hosts. Methods From April 2017 to September 2018, 153 leeches were collected from several sampling stations in small rivers with slow-flowing waters and related drainage canals located in three regions of Poland. The distinctive forms of tetracotyle metacercariae collected from leeches supplemented with adult Strigeidae specimens sampled from a wide range of water birds were analysed using the 28S rDNA partial gene, the second internal transcribed spacer region (ITS2) region and the cytochrome c oxidase (COI) fragment. Results Among investigated leeches, metacercariae of the tetracotyle type were detected in the parenchyma and musculature of 62 specimens (prevalence 40.5%) with a mean intensity reaching 19.9 individuals. The taxonomic generic affiliation of metacercariae derived from the leeches revealed the occurrence of two strigeid genera: Australapatemon Sudarikov, 1959 and Cotylurus Szidat, 1928. Phylogenetic reconstructions based on the partial 28S rRNA gene, ITS2 region and partial COI gene confirmed the separation of the Australapatemon and Cotylurus clades. Taking currently available molecular data and our results into consideration, recently sequenced tetracotyle of Australapatemon represents most probably Au. minor; however, unclear phylogenetic relationships between Au. burti and Au. minor reduce the reliability of this conclusion. On the other hand, on the basis of the obtained sequences, supplemented with previously published data, the metacercariae of Cotylurus detected in leeches were identified as two species: C. strigeoides Dubois, 1958 and C. syrius Dubois, 1934. This is the first record of C. syrius from the intermediate host. Conclusions The results of this study suggest the separation of ecological niches and life cycles between C. cornutus (Rudolphi, 1808) and C. strigeoides/C. syrius, with potential serious evolutionary consequences for a wide range of host–parasite relationships. Moreover, phylogenetic analyses corroborated the polyphyletic character of C. syrius, the unclear status of C. cornutus and the separate position of Cotylurus raabei Bezubik, 1958 within Cotylurus. The data demonstrate the inconsistent taxonomic status of the sequenced tetracotyle of Australapatemon, resulting, in our opinion, from the limited availability of fully reliable, comparative sequences of related taxa in GenBank.


2003 ◽  
Vol 93 (2) ◽  
pp. 219-228 ◽  
Author(s):  
Béatrice Denoyes-Rothan ◽  
Guy Guérin ◽  
Christophe Délye ◽  
Barbara Smith ◽  
Dror Minz ◽  
...  

Ninety-five isolates of Colletotrichum including 81 isolates of C. acutatum (62 from strawberry) and 14 isolates of C. gloeosporioides (13 from strawberry) were characterized by various molecular methods and pathogenicity tests. Results based on random amplified polymorphic DNA (RAPD) polymorphism and internal transcribed spacer (ITS) 2 sequence data provided clear genetic evidence of two subgroups in C. acutatum. The first subgroup, characterized as CA-clonal, included only isolates from strawberry and exhibited identical RAPD patterns and nearly identical ITS2 sequence analysis. A larger genetic group, CA-variable, included isolates from various hosts and exhibited variable RAPD patterns and divergent ITS2 sequence analysis. Within the C. acutatum population isolated from strawberry, the CA-clonal group is prevalent in Europe (54 isolates of 62). A subset of European C. acutatum isolates isolated from strawberry and representing the CA-clonal and CA-variable groups was assigned to two pathogenicity groups. No correlation could be drawn between genetic and pathogenicity groups. On the basis of molecular data, it is proposed that the CA-clonal subgroup contains closely related, highly virulent C. acutatum isolates that may have developed host specialization to strawberry. C. gloeosporioides isolates from Europe, which were rarely observed were either slightly or nonpathogenic on strawberry. The absence of correlation between genetic polymorphism and geographical origin in Colletotrichum spp. suggests a worldwide dissemination of isolates, probably through international plant exchanges.


Author(s):  
Miriam Rothschild

If the number of infections with (a) trematode parthenitae and cercariae using Littorina neritoides as first intermediate host only, and (b) encysted metacercariae using L. neritoides as second intermediate host only, are plotted against the size of the snails, two different curves result. The first shows a low rate of infection in the small size groups, but a steep upward slope rising to 91% in the large size groups. The second shows a curve increasing uniformly to 87% infection.Possible interpretations are discussed, and it is concluded that the difference is probably due to the fact that primary infections cause accelerated growth in the host.


Phytotaxa ◽  
2013 ◽  
Vol 146 (1) ◽  
pp. 1 ◽  
Author(s):  
PETER B. HEENAN ◽  
ROB D. SMISSEN

The generic taxonomy of the Nothofagaceae is revised. We present a new phylogenetic analysis of morphological characters and map these characters onto a recently published phylogenetic tree obtained from DNA sequence data. Results of these and previous analyses strongly support the monophyly of four clades of Nothofagaceae that are currently treated as subgenera of Nothofagus. The four clades of Nothofagaceae are robust and well-supported, with deep stem divergences, have evolutionary equivalence with other genera of Fagales, and can be circumscribed with morphological characters. We argue that these morphological and molecular differences are sufficient for the four clades of Nothofagaceae to be recognised at the primary rank of genus, and that this classification will be more informative and efficient than the currently circumscribed Nothofagus with four subgenera.        Nothofagus is recircumscribed to include five species from southern South America, Lophozonia and Trisyngyne are reinstated, and the new genus Fuscospora is described. Fuscospora and Lophozonia, with six and seven species respectively, occur in New Zealand, southern South America and Australia. Trisyngyne comprises 25 species from New Caledonia, Papua New Guinea and Indonesia. New combinations are provided where necessary in each of these genera.


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