scholarly journals Comparative Genomics of Prophages Sato and Sole Expands the Genetic Diversity Found in the Genus Betatectivirus

2021 ◽  
Vol 9 (6) ◽  
pp. 1335
Author(s):  
Annika Gillis ◽  
Louise Hock ◽  
Jacques Mahillon

Tectiviruses infecting the Bacillus cereus group represent part of the bacterial “plasmid repertoire” as they behave as linear plasmids during their lysogenic cycle. Several novel tectiviruses have been recently found infecting diverse strains belonging the B. cereus lineage. Here, we report and analyze the complete genome sequences of phages Sato and Sole. The linear dsDNA genome of Sato spans 14,852 bp with 32 coding DNA sequences (CDSs), whereas the one of Sole has 14,444 bp comprising 30 CDSs. Both phage genomes contain inverted terminal repeats and no tRNAs. Genomic comparisons and phylogenetic analyses placed these two phages within the genus Betatectivirus in the family Tectiviridae. Additional comparative genomic analyses indicated that the “gene regulation-genome replication” module of phages Sato and Sole is more diverse than previously observed among other fully sequenced betatectiviruses, displaying very low sequence similarities and containing some ORFans. Interestingly, the ssDNA binding protein encoded in this genomic module in phages Sato and Sole has very little amino acid similarity with those of reference betatectiviruses. Phylogenetic analyses showed that both Sato and Sole represent novel tectivirus species, thus we propose to include them as two novel species in the genus Betatectivirus.

Holzforschung ◽  
2018 ◽  
Vol 72 (4) ◽  
pp. 337-345 ◽  
Author(s):  
Yu Song ◽  
Xin Yao ◽  
Bing Liu ◽  
Yunhong Tan ◽  
Richard T. Corlett

AbstractAlseodaphneis a genus of timber trees (ca. 40 spp.) belonging to thePerseagroup of the Lauraceae. It is widely distributed in tropical Asia, but is often confused withDehaasiaandNothaphoebe, and the systematics of the genus is unclear. Here, the complete chloroplast genome sequences ofA. semecarpifoliawill be reported, the type species ofAlseodaphne, and two China-endemic species,A. gracilisandA. huanglianshanensis. The three plastomes were 153 051 bp, 153 099 bp and 153 070 bp, respectively. Comparative genomic analyses indicate that the threeAlseodaphneplastomes have similar genome size and those are very different with previously published plastomes of Lauraceae in length. The length difference is directly caused by inverted repeats expansion/contraction. Four highly variable loci includingpsbD-trnM,ndhF-rpl32,rpl32-trnLandycf1among the threeAlseodaphnespecies were identified as useful plastid candidate barcodes forAlseodaphneand Lauraceae species. Phylogenetic analyses based on 12 complete plastomes of Lauraceae species confirm a monophyleticPerseagroup comprising species ofAlseodaphne,Phoebe,PerseaandMachilus.


2020 ◽  
Author(s):  
R D’Archino ◽  
SM Lin ◽  
PW Gabrielson ◽  
Giuseppe Zuccarello

© 2015 British Phycological Society. Blade-forming red algae occur worldwide and, prior to DNA sequencing, had been notoriously difficult to identify and classify, especially when lacking critical reproductive features. This, coupled in New Zealand with many longstanding assumptions that taxa were identical to non-New Zealand species or genera, resulted in many misapplied names. Pugetia delicatissima R.E. Norris, an endemic New Zealand blade-forming species of the family Kallymeniaceae, is actually comprised of one existing and one new species belonging to two distinct genera, as established by our phylogenetic analyses of DNA sequences from the rbcL gene. Analyses of combined rbcL and LSU genes showed that neither is closely related to the generitype of Pugetia, the northern-eastern Pacific, P. fragilissima Kylin. We propose the names Judithia and Wendya for these two newly revealed genera. In addition to diagnostic rbcL and LSU sequences, Judithia is morphologically and anatomically characterized by rounded to oblong blades that do not taper basally at the stipe, loosely aggregated surface cortical cells and cystocarps lacking both a pericarp and an ostiole, all features observed in the holotype of P. delicatissima. Wendya, in contrast, is characterized by blades that taper both apically and basally, compactly arranged surface cortical cells and cystocarps that have both a pericarp and a distinct ostiole. The two genera also are distinguished from one other, as well as from Pugetia by features of pre- and post-fertilization development, including the number of subsidiary cells produced on carpogonial and auxiliary branch systems, whether subsidiary cells in the carpogonial branch system fuse with the supporting cell or not, and the site of origin of gonimoblast cells. Although small in area, New Zealand hosts ten of the 27 currently recognized genera in the Kallymeniaceae and is the southern-hemisphere region of greatest generic diversification in this family.


MycoKeys ◽  
2021 ◽  
Vol 85 ◽  
pp. 1-30
Author(s):  
Min Qiao ◽  
Hua Zheng ◽  
Ji-Shu Guo ◽  
Rafael F. Castañeda-Ruiz ◽  
Jian-Ping Xu ◽  
...  

The family Microthyriaceae is represented by relatively few mycelial cultures and DNA sequences; as a result, the taxonomy and classification of this group of organisms remain poorly understood. During the investigation of the diversity of aquatic hyphomycetes from southern China, several isolates were collected. These isolates were cultured and sequenced and a BLAST search of its LSU sequences against data in GenBank revealed that the closest related taxa are in the genus Microthyrium. Phylogenetic analyses, based on the combined sequence data from the internal transcribed spacers (ITS) and the large subunit (LSU), revealed that these isolates represent eight new taxa in Microthyriaceae, including two new genera, Antidactylariagen. nov. and Isthmomycesgen. nov. and six new species, Antidactylaria minifimbriatasp. nov., Isthmomyces oxysporussp. nov., I. dissimilissp. nov., I. macrosporussp. nov., Triscelophorus anisopterioideussp. nov. and T. sinensissp. nov. These new taxa are described, illustrated for their morphologies and compared with similar taxa. In addition, two new combinations are proposed in this family.


2015 ◽  
Vol 65 (Pt_9) ◽  
pp. 3203-3215 ◽  
Author(s):  
Chantal Campbell ◽  
Mobolaji Adeolu ◽  
Radhey S. Gupta

The class Negativicutes is currently divided into one order and two families on the basis of 16S rRNA gene sequence phylogenies. We report here comprehensive comparative genomic analyses of the sequenced members of the class Negativicutes to demarcate its different evolutionary groups in molecular terms, independently of phylogenetic trees. Our comparative genomic analyses have identified 14 conserved signature indels (CSIs) and 48 conserved signature proteins (CSPs) that either are specific for the entire class or differentiate four main groups within the class. Two CSIs and nine CSPs are shared uniquely by all or most members of the class Negativicutes, distinguishing this class from all other sequenced members of the phylum Firmicutes. Four other CSIs and six CSPs were specific characteristics of the family Acidaminococcaceae, two CSIs and four CSPs were uniquely present in the family Veillonellaceae, six CSIs and eight CSPs were found only in Selenomonas and related genera, and 17 CSPs were identified uniquely in Sporomusa and related genera. Four additional CSPs support a pairing of the groups containing the genera Selenomonas and Sporomusa. We also report detailed phylogenetic analyses for the Negativicutes based on core protein sequences and 16S rRNA gene sequences, which strongly support the four main groups identified by CSIs and by CSPs. Based on the results from different lines of investigation, we propose a division of the class Negativicutes into an emended order Selenomonadales containing the new families Selenomonadaceae fam. nov. and Sporomusaceae fam. nov. and two new orders, Acidaminococcales ord. nov. and Veillonellales ord. nov., respectively containing the families Acidaminococcaceae and Veillonellaceae.


1997 ◽  
Vol 17 (9) ◽  
pp. 5359-5368 ◽  
Author(s):  
E Namsaraev ◽  
P Berg

The Saccharomyces cerevisiae RAD51 gene product takes part in genetic recombination and repair of DNA double strand breaks. Rad51, like Escherichia coli RecA, catalyzes strand exchange between homologous circular single-stranded DNA (ssDNA) and linear double-stranded DNA (dsDNA) in the presence of ATP and ssDNA-binding protein. The formation of joint molecules between circular ssDNA and linear dsDNA is initiated at either the 5' or the 3' overhanging end of the complementary strand; joint molecules are formed only if the length of the overhanging end is more than 1 nucleotide. Linear dsDNAs with recessed complementary or blunt ends are not utilized. The polarity of strand exchange depends upon which end is used to initiate the formation of joint molecules. Joint molecules formed via the 5' end are processed by branch migration in the 3'-to-5' direction with respect to ssDNA, and joint molecules formed with a 3' end are processed in the opposite direction.


ZooKeys ◽  
2021 ◽  
Vol 1012 ◽  
pp. 21-53
Author(s):  
Francisco Andres Rivera-Quiroz ◽  
Booppa Petcharad ◽  
Jeremy A. Miller

The family Symphytognathidae is reported from Thailand for the first time. Three new species: Anapistula choojaiaesp. nov., Crassignatha seeliamsp. nov., and Crassignatha seedamsp. nov. are described and illustrated. Distribution is expanded and additional morphological data are reported for Patu shiluensis Lin & Li, 2009. Specimens were collected in Thailand between July and August 2018. The newly described species were found in the north mountainous region of Chiang Mai, and Patu shiluensis was collected in the coastal region of Phuket. DNA sequences are provided for all the species here studied. The relations of these symphytognathid species were tested using previously published phylogenetic analyses on micro orb-weavers. Also, we used micro CT analysis to build 3D models of the male genitalia and somatic characters of two species of Crassignatha Wunderlich, 1995. The molecular phylogeny and 3D models were used to discuss the taxonomy and circumscription of the currently valid symphytognathid genera, with focus on Crassignatha and Patu Marples, 1951. Based on this, three new combinations are suggested: Crassignatha bicorniventris (Lin & Li, 2009), comb. nov., Crassignatha quadriventris (Lin & Li, 2009), comb. nov., and Crassignatha spinathoraxi (Lin & Li, 2009), comb. nov. A new record of Crassignatha danaugirangensisMiller et al. 2014 is reported from Brunei.


2021 ◽  
Vol 12 ◽  
Author(s):  
Boo Seong Jeon ◽  
Myung Gil Park

The phylum Perkinsozoa is known as an exclusively parasitic group within alveolates and is widely distributed in various aquatic environments from marine to freshwater environments. Nonetheless, their morphology, life cycle, the identity of the host, and physiological characteristics remain still poorly understood. During intensive sampling along the west coast of Korea in October and November 2017, a new parasitoid, which shares several characteristics with the extant families Perkinsidae and Parviluciferaceae, was discovered and three strains of the new parasitoid were successfully established in cultures. Cross-infection experiments showed that among the examined planktonic groups, only dinoflagellates were susceptible to the new parasitoid, with infections observed in species belonging to eight genera. Even though the new parasitoid shared many morphological and developmental characteristics with other Perkinsozoan parasites, it differed from them by its densely packed trophocyte structure without a large vacuole or hyaline material during the growth stage. These characteristics are common among Parviluciferaceae members. Furthermore, through palintomic extracellular sporogenesis, it produced characteristic interconnected sporocytes resembling a string of beads. Phylogenetic analyses based on the small subunit and large subunit ribosomal DNA sequences revealed that the new parasitoid was distantly related to the family Parviluciferaceae and was more closely related to the families Perkinsidae and Xcellidae. Morphological, ultrastructural, and molecular data on the new parasitoid raised the need to erect a new family, i.e., Pararosariidae, within the phylum Perkinsozoa with Pararosarium dinoexitiosum gen. et sp. nov. as the type species. The isolation and establishment in culture of the new parasitoid outside the family Parviluciferaceae in the present study would contribute to the better understanding of the diversity of Perkinsozoan parasites and provide useful material for comparisons to other parasite species in the further study.


Phytotaxa ◽  
2021 ◽  
Vol 518 (1) ◽  
pp. 25-35
Author(s):  
KALLOL DAS ◽  
LEONID N. TEN ◽  
JAE-HO BAN ◽  
SEUNG-YEOL LEE ◽  
HEE-YOUNG JUNG

Fungal strains, designated KNU-NL4 and KNU-OL2, belonging to the family Didymellaceae were isolated from a soil sample collected in Miryang, Korea. Phylogenetic analyses based on a concatenated dataset of DNA sequences of ITS regions and partial sequences of ACT, CAL, TEF1-α, and β-TUB genes showed that the isolates reside in a clade together with Boeremia species but occupy the distinct phylogenetic position. Morphologically, the novel strains produce bigger conidiomata (average size 169.8 μm) than the closely related B. rhapontica (126.59 μm) and smaller than the other close neighbor B. coffeae (187.5 μm). Both novel strains also differed from them by smaller colony size and colony color on OA and MEA. The detailed descriptions, illustrations, and discussions regarding the morphological and phylogenetic analyses of the closely related species are provided to support the novelty of the isolated species. The results of phylogenetic analysis and morphological observations indicate that strains KNU-NL4 and KNU-OL2 represent a novel species in the genus Boeremia, for which the name Boeremia parva sp. nov. is proposed.


Author(s):  
Min Qiao ◽  
Hua Zheng ◽  
Jishu Guo ◽  
Rafael F. Castañeda-Ruiz ◽  
Jianping Xu ◽  
...  

The fungal family Microthyriaceae is represented by relatively few mycelial cultures and DNA sequences. As a result, the taxonomy and classification of this group of organisms remain poorly understood. Here, based on DNA sequences at four gene fragments (nuLSU rDNA, nuSSU rDNA, TEF1 and RPB2) in our analyses of aquatic hyphomycetes from southern China, we identify and report four new genera (Antidactylaria, Isthmomyces, Keqinzhangia, Pseudocoronospora) and thirteen new species (Antidactylaria minifimbriata, Pseudocoronospora hainanensis, Isthmomyces oxysporus, I. dissimilis, I. macrosporus, I. relanceatus, Keqinzhangia aquatica, Triscelophorus anakonajensis, T. anisopterioides, T. guizhouensis, T. mugecuoensis, T. multibrachiatus, T. neoseptatus; new combinations Isthmomyces asymmetrica, I. basitruncata, I. geniculata, I. lanceata, I. minima, I. rotundata) belonging to Microthyriaceae. Our results provided the first molecular evidence of asexual morph of this family and strengthened the phylogenetic placement of the family in class Dothideomycetes. The addition of these new taxa made Microthyriaceae the largest family comprising freshwater asexual genera in Pleosporomycetidae. In addition, we confirmed the monophyly of the genus Triscelophorus, the paraphyly of the genus Isthmolongispora, and revised 6 new combinations in Isthmolongispora. ITS barcoding of 13 species were also provided to help identify aquatic hyphomycetes in the future. Our results suggest that the asexual genera and sexual genera identified so far within this family have completely different ecological niches.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11912
Author(s):  
Gita G. Paskerova ◽  
Tatiana S. Miroliubova ◽  
Andrea Valigurová ◽  
Jan Janouškovec ◽  
Magdaléna Kováčiková ◽  
...  

Background Gregarines are a major group of apicomplexan parasites of invertebrates. The gregarine classification is largely incomplete because it relies primarily on light microscopy, while electron microscopy and molecular data in the group are fragmentary and often do not overlap. A key characteristic in gregarine taxonomy is the structure and function of their attachment organelles (AOs). AOs have been commonly classified as “mucrons” or “epimerites” based on their association with other cellular traits such as septation. An alternative proposal focused on the AOs structure, functional role, and developmental fate has recently restricted the terms “mucron” to archigregarines and “epimerite” to eugregarines. Methods Light microscopy and scanning and transmission electron microscopy, molecular phylogenetic analyses of ribosomal RNA genes. Results We obtained the first data on fine morphology of aseptate eugregarines Polyrhabdina pygospionis and Polyrhabdina cf. spionis, the type species. We demonstrate that their AOs differ from the mucron in archigregarines and represent an epimerite structurally resembling that in other eugregarines examined using electron microscopy. We then used the concatenated ribosomal operon DNA sequences (SSU, 5.8S, and LSU rDNA) of P. pygospionis to explore the phylogeny of eugregarines with a resolution superior to SSU rDNA alone. The obtained phylogenies show that the Polyrhabdina clade represents an independent, deep-branching family in the Ancoroidea clade within eugregarines. Combined, these results lend strong support to the hypothesis that the epimerite is a synapomorphic innovation of eugregarines. Based on these findings, we resurrect the family Polyrhabdinidae Kamm, 1922 and erect and diagnose the family Trollidiidae fam. n. within the superfamily Ancoroidea Simdyanov et al., 2017. Additionally, we re-describe the characteristics of P. pygospionis, emend the diagnoses of the genus Polyrhabdina, the family Polyrhabdinidae, and the superfamily Ancoroidea.


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