BackgroundPine moths (Lepidoptera; Bombycoidea; Lasiocampidae: Dendrolimus spp.) are among the most serious insect pests of forests, especially in southern China. Although COI barcodes (a standardized portion of the mitochondrial cytochrome c oxidase subunit I gene) can distinguish some members of this genus, the evolutionary relationships of the three morphospecies Dendrolimus punctatus, D. tabulaeformis and D. spectabilis have remained largely unresolved. We sequenced whole mitochondrial genomes of eight specimens, including D. punctatuswenshanensis. This is an unambiguous subspecies of D. punctatus, and was used as a reference for inferring the relationships of the other two morphospecies of the D. punctatus complex. We constructed phylogenetic trees from this data, including twelve published mitochondrial genomes of other Bombycoidea species, and examined the relationships of the Dendrolimus taxa using these trees and the genomic features of the mitochondrial genome.ResultsThe eight fully sequenced mitochondrial genomes from the three morphospecies displayed similar genome structures as other Bombycoidea species in terms of gene content, base composition, level of overall AT-bias and codon usage. However, the Dendrolimus genomes possess a unique feature in the large ribosomal 16S RNA subunits (rrnL), which are more than 60 bp longer than other members of the superfamily and have a higher AC proportion. The eight mitochondrial genomes of Dendrolimus were highly conservative in many aspects, for example with identical stop codons and overlapping regions. But there were many differences in start codons, intergenic spacers, and numbers of mismatched base pairs of tRNA (transfer RNA genes).Our results, based on phylogenetic trees, genetic distances, species delimitation and genomic features (such as intergenic spacers) of the mitochondrial genome, indicated that D. tabulaeformis is as close to D. punctatus as is D. punctatus wenshanensis, whereas D. spectabilis evolved independently from D. tabulaeformis and D. punctatus. Whole mitochondrial DNA phylogenies showed that D. spectabilis formed a well-supported monophyletic clade, with a clear species boundary separating it from the other congeners examined here. However, D. tabulaeformis often clustered with D. punctatus and with the subspecies D. punctatus wenshanensis. Genetic distance analyses showed that the distance between D. tabulaeformis and D. punctatus is generally less than the intraspecific distance of D. punctatus and its subspecies D. punctatus wenshanensis. In the species delimitation analysis of Poisson Tree Processes (PTP), D. tabulaeformis, D. punctatus and D. punctatus wenshanensis clustered into a putative species separated from D. spectabilis. In comparison with D. spectabilis, D. tabulaeformis and D. punctatus also exhibit a similar structure in intergenic spacer characterization. These different types of evidence suggest that D. tabulaeformis is very close to D. punctatus and its subspecies D. punctatus wenshanensis, and is likely to be another...
ABSTRACT. The avian family Ardeidae comprises long-legged freshwater and coastal birds. There has been considerable disagreement concerning the intrafamilial relationships of Ardeidae. Mitochondrial cytochrome c oxidase subunit I (COI) was used as a marker for the identification and phylogenetic analysis of avian species. In the present study, we analyzed the COI barcodes of 32 species from 17 genera belonging to the family Ardeidae. Each bird species possessed a barcode distinct from that of other bird species except for Egretta thula and E. garzetta, which shared one barcoding sequence. Kimura two-parameter distances were calculated between barcodes. The average genetic distance between species was 34-fold higher than the average genetic distance within species. Neighbor-joining and maximum likelihood methods were used to construct phylogenetic trees. Most species could be discriminated by their distinct clades in the phylogenetic tree. Both methods of phylogenetic reconstruction suggested that Zebrilus, Tigrisoma, and Cochlearius were an offshoot of the primitive herons. COI gene analysis suggested that the other herons could be divided
The carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) poses a severe therapeutic challenge to global public health, and research on CR-hvKP in older patients remain limited. In this study, we aimed to investigate the clinical and molecular characteristics and risk factors of CR-hvKP infections in older patients. We retrospectively investigated older patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) infections in the intensive care unit (ICU) between January 2020 and December 2020. The clinical data, and microbiological data including antimicrobial susceptibility testing, phenotype experiment and detection of carbapenemases, string test, virulence genes, capsular serotype-specific (cps) genes, and multilocus sequence typing, of the CR-hvKP group defined by the presence of any one of the virulence genes, including rmpA, rmpA2, iucA, iroN, and peg-344 were compared with those of CR-non-hvKP strains. Of the 80 CRKP strains, 51 (63.8%) met the definition of CR-hvKP. The main mechanism of resistance to carbapenems was the presence of the blaKPC−2 gene. Sequence type (ST)11 (81.3%, 65/80) and ST15 (16.3%, 13/80) were the most common STs in CRKP strains. The minimum inhibitory concentration (MIC)50 values of the CR-hvKP group against the six tested antibiotics (ceftazidime, ceftazidime-avibactam, imipenem-avibactam, tigecycline, levofloxacin, and Cefoperazone-Sulbactam) exhibited elevated levels than the CR-non-hvKP group. Ceftazidime and imipenem by combining avibactam (4 μg/mL) significantly decreased the MIC90 values more than 16-fold than ceftazidime and imipenem alone against Klebsiella pneumoniae carbapenemase (KPC)-2-producing K. pneumoniae. Cardiovascular disease [odds ratio (OR) = 11.956] and ST11-K64 (OR = 8.385) appeared to be independent variables associated with CR-hvKP infection by multivariate analysis. In conclusion, higher MICs of the last line antibiotic agents (ceftazidime-avibactam, tigecycline) might be a critical consideration in the clinical management of older patients where the concentration of these toxic antibiotics matters because of underlying comorbidities. Caution regarding KPC-2-producing ST11-K64 CR-hvKP as being new significant “superbugs” is required as they are widespread, and infection control measures should be strengthened to curb further dissemination in nosocomial settings in China.
BackgroundPine moths,Dendrolimusspp. (Lasiocampidae), are serious economic pests of conifer forests. Six closely related species (Dendrolimus punctatus,D. tabulaeformis,D. spectabilis,D. superans,D. houi, andD. kikuchii) occur in China and cause serious damage to coniferophyte. The complete mito genomes ofDendrolimusgenus are significant to resolve the phylogenetic relationship and provide theoretical support in pest control.MethodsThe complete mitogenomes of three species (D. superans,D. houi, andD. kikuchii) were sequenced based on PCR-amplified with universal primers, which were used to amplify initial fragments. Phylogenetic analyses were carried out with 78 complete mitogenomes of lepidopteran species from 10 superfamilies.ResultsThe complete mitochondrial genomes of these three species were 15,417, 15,381, and 15,377 bp in length, separately. The phylogenetic analyses produced consistent results for sixDendrolimusspecies based on complete mitogenomes, two major clades were formed, one containingD. spectabilisclustered withD. punctatus+D. tabulaeformis, andD. superansas the sister group to this three-taxon clade, the other containingD. kikuchiiandD. houi. Comparative analyses of the congeneric mitochondrial genomes were performed, which showed that non-coding regions were more variable than the A+T rich region. The mitochondrial nucleotide diversity was more variable when compared within than among genus, and the concatenated tRNA region was the most conserved and the nd6 genes was the most variable.
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