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1.
Microbiome ; 11(1): 18, 2023 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-36721246

RESUMO

BACKGROUND: Narrow host range is a major limitation for phage applications, but phages can evolve expanded host range through adaptations in the receptor-binding proteins. RESULTS: Here, we report that Pseudomonas phage K8 can evolve broader host range and higher killing efficiency at the cost of virion stability. Phage K8 host range mutant K8-T239A carries a mutant version of the putative baseplate wedge protein GP075, termed GP075m. While phage K8 adsorbs to hosts via the O-specific antigen of bacterial LPS, phage K8-T239A uses GP075m to also bind the bacterial core oligosaccharide, enabling infection of bacterial strains resistant to K8 infection due to modified O-specific antigens. This mutation in GP075 also alters inter-protein interactions among phage proteins, and reduces the stability of phage particles to environmental stressors like heat, acidity, and alkalinity. We find that a variety of mutations in gp075 are widespread in K8 populations, and that the gp075-like genes are widely distributed among the domains of life. CONCLUSION: Our data show that a typical life history tradeoff occurs between the stability and the host range in the evolution of phage K8. Reservoirs of viral gene variants may be widely present in phage communities, allowing phages to rapidly adapt to any emerging environmental stressors. Video Abstract.


Assuntos
Bacteriófagos , Fagos de Pseudomonas , Especificidade de Hospedeiro , Bacteriófagos/genética , Aclimatação , Genes Virais , Fagos de Pseudomonas/genética
2.
Parasit Vectors ; 16(1): 37, 2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36707856

RESUMO

BACKGROUND: Understanding the interactions between bat flies and host bats offer us fundamental insights into the coevolutionary and ecological processes in host-parasite relationships. Here, we investigated the identities, host specificity, and patterns of host association of bat flies in a subtropical region in East Asia, which is an understudied region for bat fly research. METHODS: We used both morphological characteristics and DNA barcoding to identify the bat fly species found on 11 cavernicolous bat species from five bat families inhabiting Hong Kong. We first determined the phylogenetic relationships among bat fly species. Then, we elucidated the patterns of bat-bat fly associations and calculated the host specificity of each bat fly species. Furthermore, we assembled the mitogenomes of three bat fly species from two families (Nycteribiidae and Streblidae) to contribute to the limited bat fly genetic resources available. RESULTS: We examined 641 individuals of bat flies and found 20 species, of which many appeared to be new to science. Species of Nycteribiidae included five Nycteribia spp., three Penicillidia spp., two Phthiridium spp., one Basilia sp., and one species from a hitherto unknown genus, whereas Streblidae included Brachytarsina amboinensis, three Raymondia spp., and four additional Brachytarsina spp. Our bat-bat fly association network shows that certain closely related bat flies within Nycteribiidae and Streblidae only parasitized host bat species that are phylogenetically more closely related. For example, congenerics of Raymondia only parasitized hosts in Rhinolophus and Hipposideros, which are in two closely related families in Rhinolophoidea, but not other distantly related co-roosting species. A wide spectrum of host specificity of these bat fly species was also revealed, with some bat fly species being strictly monoxenous, e.g. nycteribiid Nycteribia sp. A, Phthiridium sp. A, and streblid Raymondia sp. A, while streblid B. amboinensis is polyxenous. CONCLUSIONS: The bat fly diversity and specificity uncovered in this study have shed light on the complex bat-bat fly ecology in the region, but more bat-parasite association studies are still needed in East Asian regions like China as a huge number of unknown species likely exists. We highly recommend the use of DNA barcoding to support morphological identification to reveal accurate host-ectoparasite relationships for future studies.


Assuntos
Quirópteros , Dípteros , Animais , Dípteros/genética , Especificidade de Hospedeiro , Interações Hospedeiro-Parasita , Filogenia
3.
Arch Virol ; 168(1): 20, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36593418

RESUMO

Soybean dwarf virus (SbDV; family Tombusviridae, genus Luteovirus, species Soybean dwarf virus) can cause damaging disease epidemics in cultivated plants of the family Fabaceae. The biological characteristics of SbDV isolate WA-8, including its vector species, host range, and impact on Australian grain legume cultivars, were investigated in a series of glasshouse experiments. Isolate WA-8 was classified as the YP strain, as it was transmitted by Acyrthosiphon pisum (pea aphid) and Myzus persicae (green peach aphid) and infected known strain indicator species. Of the 18 pasture legume species inoculated with SbDV, 12 were SbDV hosts, including eight that had not been identified previously as hosts. When inoculated with SbDV, field pea (Pisum sativum), faba bean (Vicia faba), lentil (Lens culinaris), and narrow-leafed lupin cv. Jurien were the most susceptible (70 to 100% plant infection rates), and albus lupin (Lupinus albus), chickpea (Cicer arietinum), and narrow-leafed lupin cv. Mandelup were less susceptible (20 to 70%). Over the course of three experiments, chickpea was the most sensitive to infection, with a > 97% reduction in dry above-ground biomass (AGB) and a 100% reduction in seed yield. Field pea cv. Gunyah, faba bean, and lentil were also sensitive, with a 36 to 61% reduction in AGB. Field pea cv. Kaspa was relatively tolerant, with no significant reduction in AGB or seed yield. The information generated under glasshouse conditions in this study provides important clues for understanding SbDV epidemiology and suggests that it has the potential to cause damage to Australian grain legume crops in the field, especially if climate change facilitates its spread.


Assuntos
Cicer , Fabaceae , Luteovirus , Vicia faba , Luteovirus/genética , Especificidade de Hospedeiro , Austrália , Verduras
4.
Virus Res ; 324: 199025, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36528171

RESUMO

Bacteria belonging to Cronobacter and Enterobacter genera are opportunistic pathogens responsible for infections in immunocompromised patients including neonates. Phage therapy offers a safe method for pathogen elimination, however, phages must be well characterized before application. In the present study we isolated four closely related bacteriophages from the subfamily Tevenvirinae infecting Cronobacter and Enterobacter strains. Bacteriophage Pet-CM3-4 which was isolated on C. malonaticus strain possessed broader host specificity than other three phages with primary Enterobacter hosts. Based on genome sequences all these phages have been assigned to the genus Karamvirus. We also studied factors influencing the host specificity of Pet-CM3-4 phage and its host range mutant Pet-CM3-1 and observed that a lysine to glutamine substitution in the long tail fiber adhesin was the reason of the Pet-CM3-1 reduced host specificity. By characterization of phage-resistant mutants from transposon library of C. malonaticus KMB-72 strain we identified that LPS is the receptor of both phages. C. malonaticus O:3 antigen is the receptor of Pet-CM3-1 phage and the Pet-CM3-4 phage binds to structures of the LPS core region. Obtained results will contribute to our understanding of biology and evolution of Tevenvirinae phages.


Assuntos
Bacteriófagos , Cronobacter , Recém-Nascido , Humanos , Especificidade de Hospedeiro , Enterobacter/genética , Lipopolissacarídeos , Myoviridae/genética , Proteínas de Transporte
5.
Am J Primatol ; 85(2): e23458, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36504317

RESUMO

The relevance of emerging infectious diseases continues to grow worldwide as human activities increasingly extend into formerly remote natural areas. This is particularly noticeable on the island of Madagascar. As closest relatives to humans on the island, lemurs are of particular relevance as a potential origin of zoonotic pathogen spillover. Knowledge of pathogens circulating in lemur populations is, however, very poor. Particularly little is known about lemur hemoparasites. To infer host range, ecological and geographic spread of the recently described hemoparasitic nematode Lemurfilaria lemuris in northwestern Madagascar, a total of 942 individuals of two mouse lemur species (Microcebus murinus [n = 207] and Microcebus ravelobensis [n = 433]) and two rodent species (the endemic Eliurus myoxinus [n = 118] and the invasive Rattus rattus [n = 184]) were captured in two fragmented forest landscapes (Ankarafantsika National Park and Mariarano Classified Forest) in northwestern Madagascar for blood sample examination. No protozoan hemoparasites were detected by microscopic blood smear screening. Microfilaria were present in 1.0% (2/207) of M. murinus and 2.1% (9/433) of M. ravelobensis blood samples but not in rodent samples. Internal transcribed spacer 1 (ITS-1) sequences were identical to an unnamed Onchocercidae species previously described to infect a larger lemur species, Propithecus verreauxi, about 650 km further south. In contrast to expectations, L. lemuris was not detected. The finding of a pathogen in a distantly related host species, at a considerable geographic distance from the location of its original detection, instead of a microfilaria species previously described for one of the studied host species in the same region, illustrates our low level of knowledge of lemur hemoparasites, their host ranges, distribution, modes of transmission, and their zoonotic potential. Our findings shall stimulate new research that will be of relevance for both conservation medicine and human epidemiology.


Assuntos
Cheirogaleidae , Lemur , Lemuridae , Strepsirhini , Ratos , Animais , Humanos , Especificidade de Hospedeiro , Roedores , Madagáscar , Especificidade da Espécie
6.
Front Cell Infect Microbiol ; 12: 1060825, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36467721

RESUMO

Introduction: In neonatal intensive care units (NICUs), the standard chemical-based disinfection procedures do not allow a complete eradication of pathogens from environmental surfaces. In particular, the clone Staphylococcus capitis NRCS-A, a significant pathogen in neonates, was shown to colonize neonatal incubators. The aim of this study was to evaluate the in vitro effect of a bacteriophage cocktail on NRCS-A eradication. Methods: Three bacteriophages were isolated, genetically characterized and assessed for their host range using a collection of representative clinical strains (n=31) belonging to the clone NRCS-A. The efficacy of a cocktail including these three bacteriophages to eradicate the reference strain S. capitis NRCS-A CR01 was determined in comparison or in combination with the chemical disinfectant Surfanios Premium on either dry inoculum or biofilm-embedded bacteria. The emergence of bacterial resistance against the bacteriophages alone or in cocktail was evaluated by growth kinetics. Results: The three bacteriophages belonged to two families and genera, namely Herelleviridae/Kayvirus for V1SC01 and V1SC04 and Rountreeviridae/Andhravirus for V1SC05. They were active against 17, 25 and 16 of the 31 tested strains respectively. Bacteriophage cocktails decreased the bacterial inoculum of both dry spots and biofilms, with a dose dependent effect. The sequential treatment with bacteriophages then Surfanios Premium did not show enhanced efficacy. No bacterial resistance was observed when using the bacteriophage cocktail. Discussion: This study established a proof-of-concept for the use of bacteriophages to fight against S. capitis NRCS-A. Further investigations are needed using a larger bacterial collection and in real-life conditions before being able to use such technology in NICUs.


Assuntos
Bacteriófagos , Staphylococcus capitis , Humanos , Recém-Nascido , Unidades de Terapia Intensiva Neonatal , Descontaminação , Especificidade de Hospedeiro
7.
Proc Natl Acad Sci U S A ; 119(50): e2211217119, 2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36469788

RESUMO

Most new pathogens of humans and animals arise via switching events from distinct host species. However, our understanding of the evolutionary and ecological drivers of successful host adaptation, expansion, and dissemination are limited. Staphylococcus aureus is a major bacterial pathogen of humans and a leading cause of mastitis in dairy cows worldwide. Here we trace the evolutionary history of bovine S. aureus using a global dataset of 10,254 S. aureus genomes including 1,896 bovine isolates from 32 countries in 6 continents. We identified 7 major contemporary endemic clones of S. aureus causing bovine mastitis around the world and traced them back to 4 independent host-jump events from humans that occurred up to 2,500 y ago. Individual clones emerged and underwent clonal expansion from the mid-19th to late 20th century coinciding with the commercialization and industrialization of dairy farming, and older lineages have become globally distributed via established cattle trade links. Importantly, we identified lineage-dependent differences in the frequency of host transmission events between humans and cows in both directions revealing high risk clones threatening veterinary and human health. Finally, pangenome network analysis revealed that some bovine S. aureus lineages contained distinct sets of bovine-associated genes, consistent with multiple trajectories to host adaptation via gene acquisition. Taken together, we have dissected the evolutionary history of a major endemic pathogen of livestock providing a comprehensive temporal, geographic, and gene-level perspective of its remarkable success.


Assuntos
Infecções Estafilocócicas , Staphylococcus aureus , Feminino , Humanos , Bovinos , Animais , Staphylococcus aureus/genética , Gado/genética , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/veterinária , Infecções Estafilocócicas/genética , Genoma , Especificidade de Hospedeiro
8.
Viruses ; 14(12)2022 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-36560830

RESUMO

Information on rotavirus C (RVC) infection is lacking, partly because the prevalence of RVC among humans and animals worldwide is undefined. Data on the characteristics of the P genotype among RVC strains are also required. We performed systematic searches on the infection rates of RVC since 1980 based on the literature and gene sequences of the PubMed and GenBank databases. A phylogenetic tree of VP4 genes was constructed to evaluate the distribution of the P genotype of RVC from various hosts. The specific mutation motifs in VP8* with P [2]/P [4]/P [5] specificity were analyzed to elucidate their roles in host range restriction. The rate of RVC infection in humans has fallen from 3% before 2009 to 1%, whereas in animals it has risen from 10% to 25%. The P genotype of RVC showed strict host species specificity, and current human RVC infections are exclusively caused by genotype P [2]. In the VP8* hemagglutinin domain of the P [4]/P [5] genotype of swine RVC, specific insertion or deletion were found relative to the human P [2] genotype, and these motifs are a possible critical factor for host range restriction. Our findings highlight the need for further epidemiological surveillance, preventive strategies, and elucidation of the factors involved in the specific host range restriction of RVC-circulating strains.


Assuntos
Infecções por Rotavirus , Rotavirus , Animais , Humanos , Especificidade de Hospedeiro , Filogenia , Proteínas do Capsídeo/genética , Rotavirus/genética , Infecções por Rotavirus/epidemiologia , Genótipo
9.
BMC Microbiol ; 22(1): 304, 2022 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-36513996

RESUMO

The growing interest in the therapeutic application of bacteriophages leads to a drastic increase in the number of sequenced genomes. Luckily, recent insights in phage taxonomy facilitate the classification of phages in a comprehensive and data-driven manner as recently proposed by the International Committee on Taxonomy of Viruses. In this research, we present the taxonomical classification of a novel, narrow host range Xanthomonas phage FoX4, isolated from a Brussels sprouts field in Belgium infested with Xanthomonas campestris pv. campestris. The phage has a limited ability to lyse a bacterial culture, yet adsorbs efficiently to its host. Based on its genome sequence and low similarity to previously described phages, the phage comprises the novel phage genus Foxquatrovirus.


Assuntos
Bacteriófagos , Siphoviridae , Xanthomonas campestris , Bacteriófagos/genética , Genoma Viral , Siphoviridae/genética , Especificidade de Hospedeiro , Xanthomonas campestris/genética
10.
Sci Rep ; 12(1): 21855, 2022 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-36528657

RESUMO

White mold commonly known as Sclerotinia sclerotiorum causes stem rot disease and has emerged as one of the major fungal pathogens of oilseed Brassica across the world. In the present study, consistently virulent S. sclerotiorum isolate "ESR-01" was sequenced and an assembly size of ~ 41 Mb with 328 scaffolds having N50 of 447,128 was obtained. Additionally, 27,450 single nucleotide polymorphisms (SNPs) were identified from 155 scaffolds against S. sclerotiorum 1980 isolate, with an average SNP density of ~ 1.5 per kb genome. 667 repetitive elements were identified and approximately comprised 7% of the total annotated genes. The DDE_1 with 454 in numbers was found to be the most abundant and accounts for 68% of the total predicted repetitive elements. In total, 3844 simple sequence repeats are identified in the 328 scaffolds. A total of 9469 protein-coding genes were predicted from the whole genome assembly with an average gene length of 1587 bp and their distribution as 230.95 genes per Mb in the genome. Out of 9469 predicted protein-coding genes, 529 genes were observed encoding the CAZymes (Carbohydrate-Active enzymes) capable of degradation of the complex polysaccharides. Glycosyltransferase (GT) families were most abundant (49.71%) among the predicted CAZymes and GT2 (23%), GT4 (20%), and glycoside hydrolase (GH) 23% with GH18 (11%) were the prominent cell wall degrading enzyme families in the ESR-01 secretome. Besides this, 156 genes essential for the pathogen-host interactions were also identified. The effector analysis in the whole genome proteomics dataset revealed a total of 57 effector candidates (ECs) and 27 of them were having their analogs whereas the remaining 30 were novel ones. Eleven selected ECs were validated experimentally by analyzing the expression profile of the ESR-01 isolate of S. sclerotiorum. Together, the present investigation offers a better understanding of the S. sclerotiorum genome, secretome, and its effector repertoire which will help in refining the present knowledge on S. sclerotiorum-Brassica interactions and necrotrophic lifestyle of the phytopathogen in general.


Assuntos
Ascomicetos , Brassica , Especificidade de Hospedeiro , Secretoma , Mapeamento Cromossômico , Brassica/genética , Doenças das Plantas/microbiologia
11.
Viruses ; 14(12)2022 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-36560706

RESUMO

Over the last several decades, kiwifruit production has been severely damaged by the bacterial plant pathogen Pseudomonas syringae pv. actinidiae (Psa), resulting in severe economic losses worldwide. Currently, copper bactericides and antibiotics are the main tools used to control this bacterial disease. However, their use is becoming increasingly ineffective due to the emergence of antibiotic resistance. In addition, environmental issues and the changes in the composition of soil bacterial communities are also concerning when using these substances. Although biocontrol methods have shown promising antibacterial effects on Psa infection under in vitro conditions, the efficiency of antagonistic bacteria and fungi when deployed under field conditions remains unclear. Therefore, it is crucial to develop a phage-based biocontrol strategy for this bacterial pathogen. Due to the specificity of the target bacteria and for the benefit of the environment, bacteriophages (phages) have been widely regarded as promising biological agents to control plant, animal, and human bacterial diseases. An increasing number of studies focus on the use of phages for the control of plant diseases, including the kiwifruit bacterial canker. In this review, we first introduce the characteristics of the Psa-induced kiwifruit canker, followed by a description of the diversity and virulence of Psa strains. The main focus of the review is the description of recent advances in the isolation of Psa phages and their characterization, including morphology, host range, lytic activity, genome characterization, and lysis mechanism, but we also describe the biocontrol strategies together with potential challenges introduced by abiotic factors, such as high temperature, extreme pH, and UV irradiation in kiwifruit orchards. The information presented in this review highlights the potential role of phages in controlling Psa infection to ensure plant protection.


Assuntos
Actinidia , Bacteriófagos , Humanos , Pseudomonas syringae , Especificidade de Hospedeiro , Actinidia/microbiologia , Frutas/microbiologia , Doenças das Plantas/prevenção & controle , Doenças das Plantas/microbiologia
12.
Sci Rep ; 12(1): 21743, 2022 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-36526693

RESUMO

In 2019, outbreaks of hepatitis-splenomegaly syndrome (HSS) were observed in six commercial layer chicken flocks, belonging to three different Polish farms, and characterized by increased mortality, hemorrhagic hepatitis with attached blood clots on the liver surface, and splenomegaly. Diseased flocks were initially investigated for the presence of avian hepatitis E virus (aHEV) - the etiological agent of HSS - by conventional reverse transcriptase polymerase chain reaction, which revealed aHEV sequences clustering separately from all known aHEV genotypes. Additionally, an aHEV genome was identified for the first time in common pheasants, from a flock in France, using Next Generation Sequencing. This genome clustered together with the Polish aHEVs here investigated. Complete genome aHEV sequences from the HSS outbreaks confirmed the divergent cluster, with a shared nucleotide sequence identity of 79.6-83.2% with other aHEVs, which we propose to comprise a novel aHEV genotype - genotype 7. Histology and immunohistochemistry investigations in the liver and spleen established an association between aHEV and the observed lesions in the affected birds, consolidating the knowledge on the pathogenesis of aHEV, which is still largely unknown. Thus, the present investigation extends the natural host range and genotypes of aHEV and strengthens knowledge on the pathogenesis of HSS.


Assuntos
Hepatite Viral Animal , Hepevirus , Doenças das Aves Domésticas , Infecções por Vírus de RNA , Animais , Hepevirus/genética , Galinhas , Esplenomegalia , Especificidade de Hospedeiro , Genótipo , Codorniz , Filogenia
13.
Int J Mol Sci ; 23(23)2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36498920

RESUMO

The idea of using pathogens to control pests has existed since the end of the 19th century. Enterobacteria from the genus Salmonella, discovered at that time, are the causative agents of many serious diseases in mammals often leading to death. Mostly, the strains of Salmonella are able to infect a wide spectrum of hosts belonging to vertebrates, but some of them show host restriction. Several strains of these bacteria have been used as biorodenticides due to the host restriction until they were banned in many countries in the second part of the 20th century. The main reason for the ban was their potential pathogenicity for some domestic animals and poultry and the outbreaks of gastroenteritis in humans. Since that time, a lot of data regarding the host specificity and host restriction of different strains of Salmonella have been accumulated, and the complexity of the molecular mechanisms affecting it has been uncovered. In this review, we summarize the data regarding the history of studying and application of Salmonella-based rodenticides, discuss molecular systems controlling the specificity of Salmonella interactions within its multicellular hosts at different stages of infection, and attempt to reconstruct the network of genes and their allelic variants which might affect the host-restriction mechanisms.


Assuntos
Aves Domésticas , Salmonella , Animais , Humanos , Salmonella/genética , Virulência/genética , Especificidade de Hospedeiro , Enterobacteriaceae , Mamíferos
14.
J Gen Virol ; 103(11)2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36374180

RESUMO

Members of the family Pleolipoviridae are pseudo-spherical and pleomorphic archaeal viruses composed of a membrane vesicle, which encloses a DNA genome. The genome is either circular ssDNA or dsDNA, or linear dsDNA molecules of approximately 7 to 17 kilonucleotides or kbp. Typically, virions contain a single type of transmembrane spike protein at the envelope and a single type of membrane protein, which is embedded in the envelope and located in the internal side of the membrane. All viruses infect extremely halophilic archaea in the class Halobacteria (phylum Euryarchaeota). Pleolipoviruses have a narrow host range and a persistent, non-lytic life cycle. Some viruses are temperate and can integrate into the host chromosome. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Pleolipoviridae, which is available at ictv.global/report/pleolipoviridae.


Assuntos
Vírus de Archaea , Vírus , Genoma Viral , Vírus/genética , Vírus de Archaea/genética , Vírion/genética , Especificidade de Hospedeiro , Replicação Viral
15.
Emerg Infect Dis ; 28(12): 2500-2503, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36417954

RESUMO

Surveillance of bat betacoronaviruses is crucial for understanding their spillover potential. We isolated bat sarbecoviruses from Rhinolophus cornutus bats in multiple locations in Japan. These viruses grew efficiently in cells expressing R. cornutus angiotensin converting enzyme-2, but not in cells expressing human angiotensin converting enzyme-2, suggesting a narrow host range.


Assuntos
Quirópteros , Animais , Humanos , Peptidil Dipeptidase A , Japão/epidemiologia , Betacoronavirus , Especificidade de Hospedeiro
16.
J Gen Virol ; 103(11)2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36394457

RESUMO

Spinareoviridae is a large family of icosahedral viruses that are usually regarded as non-enveloped with segmented (9-12 linear segments) dsRNA genomes of 23-29 kbp. Spinareovirids have a broad host range, infecting animals, fungi and plants. Some have important pathogenic potential for humans (e.g. Colorado tick fever virus), livestock (e.g. avian orthoreoviruses), fish (e.g. aquareoviruses) and plants (e.g. rice ragged stunt virus and rice black streaked dwarf virus). This is a summary of the ICTV Report on the family Spinareoviridae, which is available at ictv.global/report/spinareoviridae.


Assuntos
Fungos , RNA de Cadeia Dupla , Animais , Humanos , Plantas , Especificidade de Hospedeiro , Filogenia
17.
BMC Microbiol ; 22(1): 278, 2022 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-36411421

RESUMO

BACKGROUND: A zucchini disease outbreak with unusual symptoms associated with Pseudomonas syringae clade 2b was identified in Bundaberg, Australia during autumn 2016. To investigate the genetic diversity of the 11 Australian isolates obtained from the outbreak, the genomes were compared to the publicly available P. syringae strains in phylogroup 2. RESULTS: Average nucleotide identity refined the P. syringae clade 2b-a into four clusters (Cluster A, B, C1 and C2), an expansion from the previously identified A, B and C. Australian isolates were in Cluster A, C1 and C2. Genomic analyses highlighted several key factors that may contribute to the virulence of these isolates. Six orthologous groups, including three virulence factors, were associated with P. syringae phylogroup 2 cucurbit-infecting strains. A region of genome plasticity analysis identified a type VI secretion system pathway in clade 2b-a strains which could also contribute to virulence. Pathogenicity assays on isolates KL004-k1, KFR003-1 and 77-4C, as representative isolates of Cluster A, C1 and C2, respectively, determined that all three isolates can infect pumpkin, squash, watermelon and zucchini var. Eva with different levels of disease severity. Subsequently, type III effectors were investigated and four type III effectors (avrRpt2, hopZ5, hopC1 and hopH1) were associated with host range. The hopZ effector family was also predicted to be associated with disease severity. CONCLUSIONS: This study refined the taxonomy of the P. syringae clade 2b-a, supported the association between effector profile and pathogenicity in cucurbits established in a previous study and provides new insight into important genomic features of these strains. This study also provided a detailed and comprehensive resource for future genomic and functional studies of these strains.


Assuntos
Genômica , Pseudomonas syringae , Pseudomonas syringae/genética , Austrália/epidemiologia , Virulência/genética , Especificidade de Hospedeiro , Verduras
18.
Folia Parasitol (Praha) ; 692022 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-36354354

RESUMO

Salmincola markewitschi Shedko et Shedko, 2002 (Copepoda: Lernaeopodidae) is an ectoparasitic copepod mainly infecting the buccal cavities of white-spotted charr Salvelinus leucomaenis (Pallas) (Salmonidae). This species has only been recorded from Northeast Asia, where a morphologically similar congener Salmincola carpionis (Krøyer, 1837) is also distributed, using the same host species. These copepods are hard to distinguish from each other because of their similarities. We thus examined the newly collected specimens morphologically and genetically from five populations of white-spotted charr in Japan. Most of the specimens were morphologically consistent with S. markewitschi but showed great variations in the numbers of spines on the exopods of the antennae, shape of the maxilliped myxal palps, and the bulla diameter. Consequently, some specimens shared characteristics with S. carpionis. In addition to the mophological continuities, genetic analyses of 28S rDNA and COI mitochondrial DNA confirmed that all specimens belong to a single species. Further taxonomic revisions are required to draw conclusions of whether S. markewitschi is a valid species different from S. carpionis, by collecting samples from across their wide distributional ranges, such as Europe, North America, and Northeast Asia. A key to identification of species of Salmincola Wilson, 1915 occurring in Japan is also provided.


Assuntos
Copépodes , Animais , Copépodes/genética , Truta/genética , Truta/parasitologia , DNA Ribossômico , Especificidade de Hospedeiro , Europa (Continente)
19.
Curr Opin Microbiol ; 70: 102225, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36327691

RESUMO

Bacteriophages are abundant and diverse predators that drive community dynamics in many ecosystems and hold great potential for biotechnology and as therapeutics for bacterial infections. Previous research has largely explored phage-host interactions one-by-one, which limited our ability to observe phenotypic patterns, to uncover their genetic basis, and to unravel the underlying molecular mechanisms. However, the famous 'toothpicks and logic' were recently joined by large-scale sequencing of phage genomes and bacterial genome-wide screens that enable us to systematically investigate phage-host interactions. In this article, we highlight recent breakthroughs from the molecular basis of phage host range and receptor recognition over new insights into bacterial immunity to the serendipitous discovery of a new bacterial surface glycan. Future work will enable the understanding, prediction, and engineering of more complicated phage traits for new applications and extend the scope of these studies from simple test tube experiments to natural communities of phages and hosts.


Assuntos
Bacteriófagos , Bacteriófagos/genética , Ecossistema , Especificidade de Hospedeiro , Sequenciamento de Nucleotídeos em Larga Escala , Lógica
20.
Sci Adv ; 8(48): eade0459, 2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36449623

RESUMO

Staphylococcus epidermidis is an opportunistic pathogen of the human skin, often associated with infections of implanted medical devices. Staphylococcal picoviruses are a group of strictly lytic, short-tailed bacteriophages with compact genomes that are attractive candidates for therapeutic use. Here, we report the structure of the complete virion of S. epidermidis-infecting phage Andhra, determined using high-resolution cryo-electron microscopy, allowing atomic modeling of 11 capsid and tail proteins. The capsid is a T = 4 icosahedron containing a unique stabilizing capsid lining protein. The tail includes 12 trimers of a unique receptor binding protein (RBP), a lytic protein that also serves to anchor the RBPs to the tail stem, and a hexameric tail knob that acts as a gatekeeper for DNA ejection. Using structure prediction with AlphaFold, we identified the two proteins that comprise the tail tip heterooctamer. Our findings elucidate critical features for virion assembly, host recognition, and penetration.


Assuntos
Especificidade de Hospedeiro , Fagos de Staphylococcus , Humanos , Staphylococcus epidermidis , Microscopia Crioeletrônica , Capsídeo , Proteínas do Capsídeo
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