MyMedR

Displaying all 5 publications

Abstract:

Sort:

Fulltext Morphological and molecular phylogenetic characterization of Sarcocystis kani sp. nov. and other novel, closely related Sarcocystis spp. infecting small mammals and colubrid snakes in Asia

Jäkel T, Raisch L, Richter S, Wirth M, Birenbaum D, Ginting S, et al.

Int J Parasitol Parasites Wildl, 2023 Dec;22:184-198.
PMID: 37915771 DOI: 10.1016/j.ijppaw.2023.10.005

We investigated the morphology and phylogenetic relationships of novel and previously recognized Sarcocystis spp. infecting small mammals and colubrid snakes in Asia. The nuclear 18S rRNA and mitochondrial cox1 of Sarcocystis sp.1 from mangrove snakes (Boiga dendrophila) in Thailand and Sarcocystis sp.2 from a ricefield rat (Rattus argentiventer) in Sumatra were partially sequenced. Sporocysts of Sarcocystis sp.1 induced development of sarcocysts in experimentally infected rats, which showed a unique ultrastructure that was observed previously by S.P. Kan in rats from Malaysia; therefore, we describe this species as Sarcocystis kani sp. nov. Its integration into the 18S rRNA phylogeny of Sarcocystis spp. cycling between small mammals and colubrid snakes helped clarify relationships among the so-called S. zuoi-complex of molecularly cryptic species: Sarcocystis kani sp. nov., S. sp.2, S. attenuati, S. scandentiborneensis, and S. zuoi were all included in this clade. Tree topology was resolved into dichotomies congruent with the morphological disparities between the taxa. However, cox1 gene sequencing (including newly sequenced S. singaporensis and S. zamani) revealed that Sarcocystis kani, S. attenuati, and S. scandentiborneensis were identical suggesting a recent, common ancestry. To identify other distinctive features, lineage-specific molecular patterns within both genes were examined revealing that all 18S rRNA sequences of the S. zuoi - complex possess a unique, 7-nt long motif in helix 38 of domain V7 that was different in S. clethrionomyelaphis which branched off basally from the complex. Three-dimensional homology modelling of COX1 protein structure identified amino acid substitutions within the barcode area specific for the S. zuoi-complex and substantial divergence in structurally important amino acids between Sarcocystis species of snakes as definitive hosts and other lineages of the Sarcocystidae. We discuss the utility of selected genes for species delimitation of the Sarcocystis spp. under investigation, which probably evolved during recent radiations of their intermediate and definitive hosts.
Fulltext Examination of Sarcocystis spp. of giant snakes from Australia and Southeast Asia confirms presence of a known pathogen - Sarcocystis nesbitti

Wassermann M, Raisch L, Lyons JA, Natusch DJD, Richter S, Wirth M, et al.

PLoS One, 2017;12(11):e0187984.
PMID: 29131856 DOI: 10.1371/journal.pone.0187984

We examined Sarcocystis spp. in giant snakes from the Indo-Australian Archipelago and Australia using a combination of morphological (size of sporocyst) and molecular analyses. We amplified by PCR nuclear 18S rDNA from single sporocysts in order to detect mixed infections and unequivocally assign the retrieved sequences to the corresponding parasite stage. Sarcocystis infection was generally high across the study area, with 78 (68%) of 115 examined pythons being infected by one or more Sarcocystis spp. Among 18 randomly chosen, sporocyst-positive samples (11 from Southeast Asia, 7 from Northern Australia) the only Sarcocystis species detected in Southeast Asian snakes was S. singaporensis (in reticulated pythons), which was absent from all Australian samples. We distinguished three different Sarcocystis spp. in the Australian sample set; two were excreted by scrub pythons and one by the spotted python. The sequence of the latter is an undescribed species phylogenetically related to S. lacertae. Of the two Sarcocystis species found in scrub pythons, one showed an 18S rRNA gene sequence similar to S. zamani, which is described from Australia for the first time. The second sequence was identical/similar to that of S. nesbitti, a known human pathogen that was held responsible for outbreaks of disease among tourists in Malaysia. The potential presence of S. nesbitti in Australia challenges the current hypothesis of a snake-primate life cycle, and would have implications for human health in the region. Further molecular and biological characterizations are required to confirm species identity and determine whether or not the Australian isolate has the same zoonotic potential as its Malaysian counterpart. Finally, the absence of S. nesbitti in samples from reticulated pythons (which were reported to be definitive hosts), coupled with our phylogenetic analyses, suggest that alternative snake hosts may be responsible for transmitting this parasite in Malaysia.
Fulltext Contaminating viral sequences in high-throughput sequencing viromics: a linkage study of 700 sequencing libraries

Asplund M, Kjartansdóttir KR, Mollerup S, Vinner L, Fridholm H, Herrera JAR, et al.

Clin Microbiol Infect, 2019 Oct;25(10):1277-1285.
PMID: 31059795 DOI: 10.1016/j.cmi.2019.04.028

OBJECTIVES: Sample preparation for high-throughput sequencing (HTS) includes treatment with various laboratory components, potentially carrying viral nucleic acids, the extent of which has not been thoroughly investigated. Our aim was to systematically examine a diverse repertoire of laboratory components used to prepare samples for HTS in order to identify contaminating viral sequences.
METHODS: A total of 322 samples of mainly human origin were analysed using eight protocols, applying a wide variety of laboratory components. Several samples (60% of human specimens) were processed using different protocols. In total, 712 sequencing libraries were investigated for viral sequence contamination.
RESULTS: Among sequences showing similarity to viruses, 493 were significantly associated with the use of laboratory components. Each of these viral sequences had sporadic appearance, only being identified in a subset of the samples treated with the linked laboratory component, and some were not identified in the non-template control samples. Remarkably, more than 65% of all viral sequences identified were within viral clusters linked to the use of laboratory components.
CONCLUSIONS: We show that high prevalence of contaminating viral sequences can be expected in HTS-based virome data and provide an extensive list of novel contaminating viral sequences that can be used for evaluation of viral findings in future virome and metagenome studies. Moreover, we show that detection can be problematic due to stochastic appearance and limited non-template controls. Although the exact origin of these viral sequences requires further research, our results support laboratory-component-linked viral sequence contamination of both biological and synthetic origin.
Evidence for the Higgs Boson Decay to a Z Boson and a Photon at the LHC

Aad G, Abbott B, Abeling K, Abicht NJ, Abidi SH, Aboulhorma A, et al.

Phys Rev Lett, 2024 Jan 12;132(2):021803.
PMID: 38277607 DOI: 10.1103/PhysRevLett.132.021803

The first evidence for the Higgs boson decay to a Z boson and a photon is presented, with a statistical significance of 3.4 standard deviations. The result is derived from a combined analysis of the searches performed by the ATLAS and CMS Collaborations with proton-proton collision datasets collected at the CERN Large Hadron Collider (LHC) from 2015 to 2018. These correspond to integrated luminosities of around 140 fb^{-1} for each experiment, at a center-of-mass energy of 13 TeV. The measured signal yield is 2.2±0.7 times the standard model prediction, and agrees with the theoretical expectation within 1.9 standard deviations.
Combination of Measurements of the Top Quark Mass from Data Collected by the ATLAS and CMS Experiments at sqrt[s]=7 and 8 TeV

Hayrapetyan A, Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, et al.

Phys Rev Lett, 2024 Jun 28;132(26):261902.
PMID: 38996325 DOI: 10.1103/PhysRevLett.132.261902

A combination of fifteen top quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The datasets used correspond to an integrated luminosity of up to 5 and 20 fb^{-1} of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, respectively. The combination includes measurements in top quark pair events that exploit both the semileptonic and hadronic decays of the top quark, and a measurement using events enriched in single top quark production via the electroweak t channel. The combination accounts for the correlations between measurements and achieves an improvement in the total uncertainty of 31% relative to the most precise input measurement. The result is m_{t}=172.52±0.14(stat)±0.30(syst) GeV, with a total uncertainty of 0.33 GeV.