Molecular and Morphological Evidence for an Origin of the Aberrant Genus Milula within Himalayan Species of Allium (Alliacae)
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Nucleotide sequences of the second internal transcribed spacer region (ITS-2) of nuclear ribosomal DNA in Н. contortus and H. placei revealed six (2.6%) nucleotide differences between these two species. The level of the intraspecific difference in ITS-2 in Haemonchus was low. A number of morphological differences together with distinctive ITS-2 sequences signatures at the molecular level clearly differentiate H. placei from Н. contortus in the
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Macrorhabdus ornithogaster (MO) is an infectious fungus that causes gastric damage in birds. In this study, we established nested and seminested polymerase chain reaction (PCR) methods that specifically amplify the domain D1/D2 region (D1/D2) of 26S ribosomal DNA (rDNA), internal transcribed spacer (ITS) of rDNA, and intergenic spacer (IGS) 1 region from avian feces. Phylogenetic analysis of MO collected from Japanese pet birds showed little genetic variation; analysis based on these regions did not distinguish between host species order, differences in MO shape, or host gastrointestinal symptoms. These regions were found to be unsuitable for molecular epidemiological studies of MO and further investigation into other genetic regions is required.
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Abstract Differences in sequences of ribosomal DNA second internal transcribed spacer (ITS) among Anopheles sinensis, An. lesteri and An. yatsushiroensis from Korea were compared. The PCR amplified rDNA‐ITS2 fragments were sequenced directly. Three samples of each species were individually determined. Lengths of the ITS2 regions were 468bp in An sinensis , 451bp in An lesteri and 453bp in An yatsushiroenesis and GC contents were 44.87 % 46.2 % and 45.7 % respectively. Variations of the sequences ranged from 12.16 % to 30.7 % among the three species. The differences of the rDNA‐ITS2 sequences would be useful for molecular identification of the three members of Anopheles hycanus complex from Korea.
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Objective:To compare the sequence difference of the ribosomal DNA second internal transcribed spacer (ITS2) in the different strains of Anopheles minimus in Yunnan. Methods: The PCR amplified rDNA ITS2 sequences, to compare the variation of An. minimus . Results: The different strains of 6 populations were sequenced, which could be separate into Anopheles minimus A and C. Conclusion: The sequence difference of the rDNA ITS2 would be very useful for the developing a molecular approach to distinguish An. minimus A and C.
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Accurate identification of sheep nematodes is a critical point in epidemiological studies and monitoring of drug resistance in flocks. However, due to a close morphological similarity between the eggs and larval stages of many of these nematodes, such identification is not a trivial task. There are a number of studies showing that molecular targets in ribosomal DNA (Internal transcribed spacer 1, 2 and Intergenic spacer) are suitable for accurate identification of sheep bursate nematodes. The objective of present study was to compare the ITS1, ITS2 and IGS regions of Iranian common bursate nematodes in order to choose best target for specific identification methods.
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Teladorsagia circumcincta
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Differences in sequences of ribosomal DNA second internal transcribed spacer (ITS2) among Anopheles sinensis, An. lesteri and An. yatsushiroensis from Korea were compared. The PCR amplified rDNA\|ITS2 fragments were sequenced directly. Three samples of each species were individually determined. Lengths of the ITS2 regions were 468bp in An. sinensis, 451bp in An. lesteri and 453bp in An. yatsushiroenesis and GC contents were 44 87 %, 46 2 % and 45 7 % respectively Variations of the sequences ranged from 12 16 % to 30 7 % among the three species. The differences of the rDNA\|ITS2 sequences would be useful for molecular identification of the three members of Anopheles hyrcanus complex from Korea.
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ABSTRACT Most of the 3,000 named species in the genus Cercospora have no known sexual stage, although a Mycosphaerella teleomorph has been identified for a few. Mycosphaerella is an extremely large and important genus of plant pathogens, with more than 1,800 named species and at least 43 associated anamorph genera. The goal of this research was to perform a large-scale phylogenetic analysis to test hypotheses about the past evolutionary history of Cercospora and Mycosphaerella. Based on the phylogenetic analysis of internal transcribed spacer (ITS) sequence data (ITS1, 5.8S rRNA gene, ITS2), the genus Mycosphaerella is monophyletic. In contrast, many anamorph genera within Mycosphaerella were polyphyletic and were not useful for grouping species. One exception was Cercospora, which formed a highly supported monophyletic group. Most Cercospora species from cereal crops formed a subgroup within the main Cercospora cluster. Only species within the Cercospora cluster produced the toxin cercosporin, suggesting that the ability to produce this compound had a single evolutionary origin. Intraspecific variation for 25 taxa in the Mycosphaerella clade averaged 1.7 nucleotides (nts) in the ITS region. Thus, isolates with ITS sequences that differ by two or more nucleotides may be distinct species. ITS sequences of groups I and II of the gray leaf spot pathogen Cercospora zeae-maydis differed by 7 nts and clearly represent different species. There were 6.5 nt differences on average between the ITS sequences of the sorghum pathogen Cercospora sorghi and the maize pathogen Cercospora sorghi var. maydis, indicating that the latter is a separate species and not simply a variety of Cercospora sorghi. The large monophyletic Mycosphaerella cluster contained a number of anamorph genera with no known teleomorph associations. Therefore, the number of anamorph genera related to Mycosphaerella may be much larger than suspected previously.
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Objective:To introduce the recent progress on the structural features of Ribosomal DNA internal transcribed spacer sequence and application in parasitology.Methods:Relative literatures were summarized and analyzed.Results:Ribosomal DNA internal transcribed spacer 1and internal transcribed spacer 2 sequence provided very valuable genetic markers in identification of parasites.Conclusion:Ribosomal DNA internal transcribed spacer evolutionary faster than other regions.It had high variability and a lot of genetic information could be acquired.So Ribosomal DNA internal transcribed spacer has become a effective means in the classification identification in parasites species and subspecies.
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Background and Objective: The banana ranks among the top fruits in the world.Production of bananas is beset with problems of pest and disease infestation.The local Philippine cultivar ʻSabaʼ has been reported to possess resistance to major diseases affecting other banana cultivars.This study assessed fungal species present in the soil rhizosphere of ʻSabaʼ banana.Materials and Methods: Fungal isolates obtained and purified from the soil and were characterized morphologically in a previous study.These were identified by amplifying the ITS-5.8SrDNA sequences.Prior to amplification, the isolation of fungal DNA was optimized by the freeze-thaw method where mycelia were collected and stored at -80EC for 48 h.Then, a modified CTAB method was used to extract DNA.The PCR fragments were amplified using the primers Forward: ITS1 (5ʼ-TCCGTAGGTGAACCTGCGG-3ʼ) and Reverse: ITS 4 (5ʼ-TCCTCCGCTTATTGATATGC-3).The cycling conditions were as follows: Initial denaturation at 95EC for 2 min, denaturation at 95EC for 1 min, annealing at 60EC for 1 min, 35 cycles, extension at 72EC for 1.5 min and final extension at 95EC for 5 min.Multiple sequence alignment and phylogenetic analyses were performed.Results: Fungal DNA has been successfully isolated.Two out of three fungal species whose morphological characteristics were earlier reported to conform with Aspergillus were validated in this study.Isolate 2, Aspergillus niger strain was deposited and assigned Genbank Accession No. KX093813.Isolate 3 (Genbank Accession No. KX073814) was identified as another strain of Aspergillus.They were shown to belong to a common clade with Aspergillus strains that were derived from rhizospheric soil.Strains of Aspergillus have been reported to possess various roles among which are as causal organisms of fruit rot, agents for bioremediation, antagonists of Fusarium species as well as producers of organic acids, enzymes and nutraceuticals.Conclusion: The amplification of ITS-5.8SrDNA sequences is a powerful tool in the identification of fungal species.Knowledge of fungal communities associated with plants are key to managing their health and future coping mechanism against potential pests.
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