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2.
Sci Rep ; 10(1): 12522, 2020 Jul 22.
Article in English | MEDLINE | ID: mdl-32694528

ABSTRACT

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

3.
Sci Rep ; 10(1): 9217, 2020 06 08.
Article in English | MEDLINE | ID: mdl-32513947

ABSTRACT

Noroviruses (NoVs) are one of the major causative agents of non-bacterial gastroenteritis in humans worldwide. NoVs, belonging to Caliciviridae, are classified into ten genogroups (G) and eight P-groups based on major capsid protein (VP1) and of the RNA-dependent-RNA-polymerase (RdRp), respectively. In swine, the main genogroup and P-group identified are GII and GII.P; which can infect humans too. To date, only one case of GIIP.11 have been identified in swine in Italy while the circulation of other P-types is currently unknown. In the present study, 225 swine faecal samples were collected from 74 swine herds in Veneto region through on-farm monitoring. NoV circulation was particularly high in older pigs. The phylogenetic analysis showed the co-circulation of NoVs belonging to two different P-types: GII.P11 and GII.P18, here described for the first time in Italy, presenting an extensive genetic diversity, never described before worldwide. Distinct NoV genetic subgroups and unique amino acid mutations were identified for each P-type for the first time. This study demonstrated the co-circulation of diverse swine NoVs subgroups in Italy, raising questions on the origin of such diversity and suggesting that continuous monitoring of swine NoVs is needed to track the emergence of potentially zoonotic viruses by recombination events.


Subject(s)
Gastroenteritis/pathology , Genetic Variation , Norovirus/genetics , Swine Diseases/pathology , Aging , Animals , Capsid Proteins/genetics , Feces/virology , Gastroenteritis/epidemiology , Gastroenteritis/virology , Italy/epidemiology , Mutation , Norovirus/isolation & purification , Phylogeny , Prevalence , RNA-Dependent RNA Polymerase/classification , RNA-Dependent RNA Polymerase/genetics , Swine , Swine Diseases/epidemiology , Swine Diseases/virology
4.
Dis Aquat Organ ; 135(1): 33-41, 2019 Jun 20.
Article in English | MEDLINE | ID: mdl-31219433

ABSTRACT

Investigation of mortalities in isolated wild amphibian populations presents diagnostic difficulties that can hinder reaching a definitive diagnosis for the cause of death. Disease can only be diagnosed when pathogen presence (e.g. detection by PCR) is linked to tissue lesions (histopathology) in the host. We report a 2-site outbreak of ranavirosis in wild anuran tadpoles in the boreal forest of Wood Buffalo National Park, Canada, diagnosed by histologic and molecular techniques. Mortalities occurred in wood frog Rana sylvatica tadpoles and boreal chorus frog Pseudacris maculata tadpoles. Lack of mortality in sympatric Canadian toad Bufo (Anaxyrus) hemiophrys tadpoles suggested lower disease susceptibility in this species. In the former 2 species, ranavirosis was diagnosed based on consistent histopathology, immunohistochemistry (IHC), in situ hybridization (ISH), and quantitative PCR results. The most common histopathologic lesion present in wood and boreal chorus frog tadpoles was necrosis of the skin, oral mucosa, renal tubular epithelium, renal hematopoietic tissue, and branchial epithelium. Mild hepatic and pancreatic necrosis and rare intracytoplasmic inclusion bodies in hepatocytes were less common. Skeletal and connective tissues in budding limbs often had multifocal to coalescing necrosis and were intensely positive for ranavirus, with IHC staining even in areas where no obvious necrosis could be observed. Abundant IHC and ISH staining in actively growing tissues support a link between disease emergence and amphibian developmental stage. Our findings provide a definitive diagnosis of ranavirosis in free-living amphibians and highlight the effectiveness of multi-tool approaches to mortality investigation and elucidation of pathogenesis of ranavirosis in wild amphibians.


Subject(s)
DNA Virus Infections , Ranavirus , Animals , Canada , DNA Virus Infections/veterinary , Disease Outbreaks , Larva , Taiga
5.
Nanoscale ; 11(22): 10896-10910, 2019 Jun 06.
Article in English | MEDLINE | ID: mdl-31139801

ABSTRACT

We study the mechanism of heat generation, induced by an alternating magnetic field, in magnetite nanoparticles doped with manganese, produced by thermal decomposition from organometallic precursors. We investigate a set of four samples obtained by varying the duration of the reflux treatment carried out at a temperature of 300 °C during the synthetic procedure. On increasing this parameter from 60 to 180 minutes, the mean size of the nanoparticles increases, though remaining below 10 nm, as well as the saturation magnetization, which in all the samples, thanks to the Mn doping, is higher than that in magnetite nanoparticles taken as a reference. The combination of these two events has two main consequences. First, it determines the intensity of dipolar interactions between the nanoparticles, thus influencing their magnetic relaxing behavior, which, in turn, is closely related to the heating efficiency. Secondly, in a heating test, it is possible to operate in the regime of non-linear magnetic response of the nanoparticles at values of amplitude and frequency of the alternating field usually employed for biomedical applications. We show that, in this regime, the Specific Absorption Rate (SAR) in each sample depends linearly on the fraction of nanoparticles that are not superparamagnetic. This opens the possibility of modulating the heating capacity of the produced nanoparticles, so as to match specific needs, changing only a single synthesis parameter and opportunely exploiting the strict connection between structural features, magnetic properties and measurement conditions.

6.
Vet Pathol ; 54(3): 531-548, 2017 05.
Article in English | MEDLINE | ID: mdl-28060677

ABSTRACT

Wood frogs ( Rana sylvatica) are highly susceptible to infection with Frog virus 3 (FV3, Ranavirus, Iridoviridae), a cause of mass mortality in wild populations. To elucidate the pathogenesis of FV3 infection in wood frogs, 40 wild-caught adults were acclimated to captivity, inoculated orally with a fatal dose of 104.43 pfu/frog, and euthanized at 0.25, 0.5, 1, 2, 4, 9, and 14 days postinfection (dpi). Mild lesions occurred sporadically in the skin (petechiae) and bone marrow (necrosis) during the first 2 dpi. Severe lesions occurred 1 to 2 weeks postinfection and consisted of necrosis of medullary and extramedullary hematopoietic tissue, lymphoid tissue in spleen and throughout the body, and epithelium of skin, mucosae, and renal tubules. Viral DNA was first detected (polymerase chain reaction) in liver at 4 dpi; by dpi 9 and 14, all viscera tested (liver, kidney, and spleen), skin, and feces were positive. Immunohistochemistry (IHC) first detected viral antigen in small areas devoid of histologic lesions in the oral mucosa, lung, and colon at 4 dpi; by 9 and 14 dpi, IHC labeling of viral antigen associated with necrosis was found in multiple tissues. Based on IHC staining intensity and lesion severity, the skin, oral, and gastrointestinal epithelium and renal tubular epithelium were important sites of viral replication and shedding, suggesting that direct contact (skin) and fecal-oral contamination are effective routes of transmission and that skin tissue, oral, and cloacal swabs may be appropriate antemortem diagnostic samples in late stages of disease (>1 week postinfection) but poor samples to detect infection in clinically healthy frogs.


Subject(s)
DNA Virus Infections/veterinary , Ranavirus , Ranidae/virology , Animals , Animals, Wild/virology , DNA Virus Infections/pathology , DNA Virus Infections/virology , Male , Ranavirus/pathogenicity , Ranidae/genetics , Reverse Transcriptase Polymerase Chain Reaction/veterinary
7.
Med Biol Eng Comput ; 55(7): 1097-1108, 2017 Jul.
Article in English | MEDLINE | ID: mdl-27696129

ABSTRACT

Tissue electrical conductivity is correlated with tissue characteristics. In this work, some soft tissue sarcomas (STS) excised from patients have been evaluated in terms of histological characteristics (cell size and density) and electrical resistance. The electrical resistance has been measured using the ex vivo study on soft tissue tumors electrical characteristics (ESTTE) protocol proposed by the authors in order to study electrical resistance of surgical samples excised by patients in a fixed measurement setup. The measurement setup includes a voltage pulse generator (700 V, 100 µs long at 5 kHz, period 200 µs) and an electrode with 7 needles, 20 mm-long, with the same distance arranged in a fixed hexagonal geometry. In the ESTTE protocol, the same voltage pulse sequence is applied to each different tumor mass and the corresponding resistance has been evaluated from voltage and current recorded by the equipment. For each tumor mass, a histological sample of the volume treated by means of voltage pulses has been taken for histological analysis. Each mass has been studied in order to identify the sarcoma type. For each histological sample, an image at 20× or 40× of magnification was acquired. In this work, the electrical resistance measured for each tumor has been correlated with tissue characteristics like the type, size and density of cells. This work presents a preliminary study to explore possible correlations between tissue characteristics and electrical resistance of STS. These results can be helpful to adjust the pulse voltage intensity in order to improve the electrochemotherapy efficacy on some histotype of STS.


Subject(s)
Electric Impedance , Sarcoma/pathology , Humans , Sarcoma/physiopathology
8.
World J Biol Psychiatry ; 17(4): 244-57, 2016 Jun.
Article in English | MEDLINE | ID: mdl-26895183

ABSTRACT

UNLABELLED: Objectives Growing interest focuses on the association between 5-HTTLPR polymorphism and eating disorders (ED), but published findings have been conflicting. Methods The Italian BIO.VE.D.A. biobank provided 976 samples (735 ED patients and 241 controls) for genotyping. We conducted a literature search of studies published up to 1 April 2015, including studies reporting on 5HTTLPR genotype and allele frequencies in obesity and/or ED. We ran a meta-analysis, including data from BIO.VE.D.A. - comparing low and high-functioning genotype and allele frequencies in ED vs. CONTROLS: Results Data from 21 studies, plus BIO.VE.D.A., were extracted providing information from 3,736 patients and 2,707 controls. Neither low- nor high-functioning genotype frequencies in ED patients, with both bi- and tri-allelic models, differed from controls. Furthermore, neither low- nor high-functioning allele frequencies in ED or in BN, in both bi- and triallelic models, differed from control groups. After sensitivity analysis, results were the same in AN vs. CONTROLS: Results remained unaltered when investigating recessive and dominant models. Conclusions 5HTTLPR does not seem to be associated with ED in general, or with AN or BN in particular. Future studies in ED should explore the role of ethnicity and psychiatric comorbidity as a possible source of bias.


Subject(s)
Anorexia Nervosa/genetics , Bulimia Nervosa/genetics , Serotonin Plasma Membrane Transport Proteins/genetics , Biological Specimen Banks , Gene Frequency , Genetic Predisposition to Disease , Humans , Obesity , Polymorphism, Genetic
9.
Med Biol Eng Comput ; 54(5): 773-87, 2016 May.
Article in English | MEDLINE | ID: mdl-26324245

ABSTRACT

This paper presents a study about electrical resistance, which using fixed electrode geometry could be correlated to the tissue resistivity, of different histological types of human soft tissue sarcomas measured during electroporation. The same voltage pulse sequence was applied to the tumor mass shortly after surgical resection by means of a voltage pulse generator currently used in clinical practice for electrochemotherapy that uses reversible electroporation. The voltage pulses were applied by means of a standard hexagonal electrode composed by seven, 20-mm-long equispaced needles. Irrespective of tumor size, the electrode applies electric pulses to the same volume of tissue. The resistance value was computed from the voltage and current recorded by the pulse generator, and it was correlated with the histological characteristics of the tumor tissue which was assessed by a dedicated pathologist. Some differences in resistance values, which could be correlated to a difference in tissue resistivity, were noticed according to sarcoma histotype. Lipomatous tumors (i.e., those rich in adipose tissue) displayed the highest resistance values (up to 1700 Ω), whereas in the other soft tissue sarcomas, such as those originating from muscle, nerve sheath, or fibrous tissue, the electrical resistance measured was between 40 and 110 Ω. A variability in resistance was found also within the same histotype. Among lipomatous tumors, the presence of myxoid tissue between adipocytes reduced the electrical resistance (e.g., 50-100 Ω). This work represents the first step in order to explore the difference in tissue electrical properties of STS. These results may be used to verify whether tuning electric field intensity according to the specific STS histotype could improve tissue electroporation and ultimately treatment efficacy.


Subject(s)
Electric Impedance , Sarcoma/physiopathology , Sarcoma/surgery , Cell Differentiation , Electrodes , Humans , Sarcoma/pathology
10.
Technol Cancer Res Treat ; 15(2): 296-307, 2016 Apr.
Article in English | MEDLINE | ID: mdl-25911645

ABSTRACT

Electrochemotherapy (ECT) is a local anticancer treatment based on the combination of chemotherapy and short, tumor-permeabilizing, voltage pulses delivered using needle electrodes or plate electrodes. The application of ECT to large skin surface tumors is time consuming due to technical limitations of currently available voltage applicators. The availability of large pulse applicators with few and more spaced needle electrodes could be useful in the clinic, since they could allow managing large and spread tumors while limiting the duration and the invasiveness of the procedure. In this article, a grid electrode with 2-cm spaced needles has been studied by means of numerical models. The electroporation efficiency has been assessed on human osteosarcoma cell line MG63 cultured in monolayer. The computational results show the distribution of the electric field in a model of the treated tissue. These results are helpful to evaluate the effect of the needle distance on the electric field distribution. Furthermore, the in vitro tests showed that the grid electrode proposed is suitable to electropore, by a single application, a cell culture covering an area of 55 cm(2). In conclusion, our data might represent substantial improvement in ECT in order to achieve a more homogeneous and time-saving treatment, with benefits for patients with cancer.


Subject(s)
Electrochemotherapy/instrumentation , Cell Line, Tumor , Electrodes , Humans , Models, Theoretical , Neoplasms/drug therapy , Solanum tuberosum
11.
New Microbes New Infect ; 7: 41-7, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26199731

ABSTRACT

The aim of this study was to further investigate the role of wild boar (Sus scrofa) as a reservoir for hepatitis E virus (HEV). Sixty-four blood and faecal samples collected from wild boar hunted in Central Italy in 2011-2012 were examined by indirect enzyme-linked immunosorbent assay and RT-PCR analysis. Positive RT-PCR samples were further examined by nucleotide sequence determination and subsequent phylogenetic analysis. Thirty-six sera (56.2%) were positive for HEV-specific antibodies, and six (9.4%) faecal samples scored RT-PCR-positive results. Four animals were positive by both enzyme-linked immunosorbent assay and RT-PCR. Phylogenetic analysis showed that the detected wild boar-derived HEV sequences clustered within genotype 3, with similarity to sequences of human origin collected in a nearby area in 2012. Our data confirm that HEV is endemic in the wild boar population in the research area and that these wild animals could play an important role in the epidemiology of HEV infection.

12.
Theriogenology ; 83(6): 1021-7, 2015 Apr 01.
Article in English | MEDLINE | ID: mdl-25557187

ABSTRACT

There is a growing interest in chemical sterilization as an alternative to surgical castration in large-scale sterilization campaigns to control canine populations. An important step toward understanding the short-term and long-term effects of chemical sterilants is to determine their impact on blood testosterone concentrations, particularly as these could influence dog behavior after treatment. A field trial was conducted with 118 free-roaming male dogs in the Chilean Patagonia, where 36 dogs were chemically sterilized using EsterilSol, 39 dogs were surgically castrated, and 43 dogs remained intact as controls. Blood testosterone levels were determined at four time periods: on enrollment 6 months before treatment (t-6m), at the time of treatment (t0, within one hour after surgical castration or chemical sterilization and during a concurrent 2-week period for the control group), four (t+4m), and six (t+6m) months after treatment. Intrinsic and temporal factors were evaluated; age was significantly associated with testosterone, where dogs 2- to 4-year-old had the highest testosterone concentrations (P = 0.036), whereas body weight and body condition scores were not associated with testosterone; testosterone concentration was not influenced by time of day, month, or season. After treatment (t+4m and t+6m), all of the surgically castrated dogs had testosterone concentrations below 1.0 ng/mL. On the basis of this cut point (<1 ng/mL), testosterone remained unchanged in 66% of the chemically sterilized dogs at both t+4m and t+6m; it remained low for 22% of dogs at both t+4m and t+6m; it was unchanged at t+4m but low at t+6m in 9% of dogs; and, it was low at t+4m but reverted back to unchanged at t+6m in one dog (3%). Incidentally, testosterone in chemically sterilized dogs increased dramatically within 1 hour of treatment (t0), more than doubling (131%) the concentration of control dogs at the time of treatment (t0), likely because of severe necrosis of interstitial cells. The use of EsterilSol as a method of sterilizing dogs had a variable effect on blood testosterone concentrations. Approximately, 30% of chemically sterilized dogs had a reduced testosterone concentration (actual maximum, 1 ng/mL) after 6 months, similar to that of surgically castrated dogs. Most chemically sterilized dogs, however, showed no long-term changes in blood testosterone concentrations.


Subject(s)
Chemosterilants/pharmacology , Dogs , Gluconates/pharmacology , Orchiectomy/veterinary , Sterilization, Reproductive/veterinary , Testosterone/blood , Animals , Gluconates/administration & dosage , Male , Orchiectomy/methods , Sterilization, Reproductive/methods
13.
Vet Pathol ; 52(2): 384-7, 2015 Mar.
Article in English | MEDLINE | ID: mdl-24823808

ABSTRACT

Amphibians in the family Ranidae (true frogs) seem highly susceptible to oxalosis, particularly when fed a diet high in oxalic acid during the premetamorphic (tadpole) stage. The authors describe the mortality of 150 captive-raised wood frogs (Rana sylvatica or Lithobates sylvaticus) from oxalate nephrolithiasis and renal tubular necrosis caused by consumption of boiled spinach during tadpole development. Renal lesions were due to intraluminal transparent crystals which were birefringent under polarized light and were identified morphologically and histochemically as composed of calcium oxalate. Evidence of early fibrosis or squamous metaplasia, and a presentation at least 2 weeks after spinach consumption had ended, suggested a subacute course. Tadpole-feeding protocols should avoid plants with high oxalate content (eg, spinach and rhubarb leaves), and any episode of high mortality in captive amphibians along with nephrolithiasis should prompt an evaluation of the feed sources for material with high oxalate content.


Subject(s)
Calcium Oxalate/adverse effects , Kidney Cortex Necrosis/veterinary , Nephrolithiasis/veterinary , Ranidae , Spinacia oleracea/chemistry , Animals , Kidney/pathology , Kidney Cortex Necrosis/pathology , Larva , Nephrolithiasis/pathology
14.
Clin Genet ; 85(4): 386-9, 2014 Apr.
Article in English | MEDLINE | ID: mdl-23621909

ABSTRACT

Neurofibromatosis type 1 (NF1) is caused by loss of function mutations of the NF1 gene, which are de novo in 50% of cases. Although this gene shows one of the highest mutation rates in the human genome, germline mosaicism is very rare in this condition. We describe the molecular analysis of a family in which neurofibromatosis type 1 occurred in two out of four siblings born to unaffected parents. Molecular analysis of the NF1 gene identified in both patients the same splicing mutation c.1392+1G>A, which was absent in parental lymphocytes. Microsatellite analysis showed that the two affected siblings shared the same maternal allele, however a specific PCR-RFLP assay excluded the presence of the NF1 splicing mutation in multiple maternal tissues. Our molecular and clinical findings are consistent with a germline mosaicism for the NF1 splicing mutation. This is the first case of maternal germline mosaicism for a NF1 mutation characterized so far at the molecular level. Our data confirm that germline mosaicism is rare in neurofibromatosis 1, but it has important implications for genetic counseling.


Subject(s)
Mosaicism , Neurofibromatosis 1/genetics , Neurofibromin 1/genetics , Female , Germ-Line Mutation , Humans , Neurofibromatosis 1/etiology , Pedigree , Siblings
15.
Vet Pathol ; 51(4): 820-3, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24078007

ABSTRACT

Intratesticular injection of EsterilSol (zinc gluconate neutralized with arginine) is a chemical sterilant for male dogs sometimes used in population control campaigns. Adverse reactions have been reported in 1% to 4% of treated dogs, but detailed histomorphologic descriptions are lacking. During a behavioral study conducted in the Chilean Patagonia in 2012, severe necrosuppurative orchitis and ulcerative dermatitis were observed in 2 of 36 (6%) dogs sterilized with EsterilSol according to the manufacturer's instructions. Reactions were noted on days 8 and 7 postinjection and required scrotal ablation on days 8 and 13, respectively; neither reaction was associated with the injection site. Although self-trauma following administration may have contributed, the cause of the adverse reactions is uncertain. EsterilSol is a relatively uncomplicated method to sterilize male dogs, but the occurrence of severe adverse reactions several days after administration emphasizes the need for the provision of long-term monitoring and veterinary care during sterilization campaigns using this product.


Subject(s)
Dermatitis/veterinary , Dog Diseases/chemically induced , Dog Diseases/pathology , Gluconates/adverse effects , Necrosis/veterinary , Orchitis/veterinary , Scrotum/pathology , Animals , Castration/adverse effects , Castration/veterinary , Dermatitis/pathology , Dogs , Gluconates/metabolism , Histological Techniques/veterinary , Male , Necrosis/chemically induced , Necrosis/pathology , Orchitis/chemically induced , Orchitis/pathology , Testis/metabolism
17.
J Gen Virol ; 92(Pt 7): 1493-1499, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21471320

ABSTRACT

The prophylactic use of topical antiviral agents has recently been validated by the reduction in human immunodeficiency virus (HIV) type 1 infection incidence seen using tonofovir-containing microbicides. In order to develop a wide-spectrum microbicide to prevent infection with a wide range of sexually transmitted viruses, we have previously reported the development of HIV-neutralizing aptamers and here report the isolation and characterization of aptamers that neutralize herpes simplex virus type 2 (HSV-2). These aptamers bind the envelope glycoprotein (gD), are potent (IC(50) of 20-50 nM) and are able to block infection pathways dependent on both major entry receptors, Nectin1 and HVEM. Structural analysis and mutagenesis of these aptamers reveal a core specificity element that could provide the basis for pharmaceutical development. As HSV-2 is a major risk factor for the acquisition of HIV-1, a microbicide capable of preventing HSV-2 infection would not only reduce the morbidity associated with HSV-2, but also that derived from HIV-1.


Subject(s)
Antiviral Agents/pharmacology , Aptamers, Nucleotide/pharmacology , Herpes Simplex/virology , Herpesvirus 2, Human/drug effects , Animals , Antiviral Agents/chemistry , Aptamers, Nucleotide/chemistry , Base Sequence , Cell Adhesion Molecules/metabolism , Herpes Simplex/drug therapy , Herpesvirus 1, Human/drug effects , Herpesvirus 1, Human/genetics , Herpesvirus 1, Human/physiology , Herpesvirus 2, Human/genetics , Herpesvirus 2, Human/physiology , Humans , Molecular Sequence Data , Nectins
18.
Dis Aquat Organ ; 91(2): 91-6, 2010 Sep 02.
Article in English | MEDLINE | ID: mdl-21387987

ABSTRACT

Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has resulted in the decline or extinction of approximately 200 frog species worldwide. It has been reported throughout much of North America, but its presence on Prince Edward Island (PEI), on the eastern coast of Canada, was unknown. To determine the presence and prevalence of Bd on PEI, skin swabs were collected from 115 frogs from 18 separate sites across the province during the summer of 2009. The swabs were tested through single round end-point PCR for the presence of Bd DNA. Thirty-one frogs were positive, including 25/93 (27%) green frogs Lithobates (Rana) clamitans, 5/20 (25%) northern leopard frogs L. (R.) pipiens, and 1/2 (50%) wood frogs L. sylvaticus (formerly R. sylvatica); 12 of the 18 (67%) sites had at least 1 positive frog. The overall prevalence of Bd infection was estimated at 26.9% (7.2-46.7%, 95% CI). Prevalence amongst green frogs and leopard frogs was similar, but green frogs had a stronger PCR signal when compared to leopard frogs, regardless of age (p < 0.001) and body length (p = 0.476). Amongst green frogs, juveniles were more frequently positive than adults (p = 0.001). Green frogs may be the most reliable species to sample when looking for Bd in eastern North America. The 1 wood frog positive for Bd was found dead from chytridiomycosis; none of the other frogs that were positive for Bd by PCR showed any obvious signs of illness. Further monitoring will be required to determine what effect Bd infection has on amphibian population health on PEI.


Subject(s)
Chytridiomycota/isolation & purification , Mycoses/veterinary , Ranidae , Animals , Mycoses/epidemiology , Mycoses/microbiology , Prince Edward Island/epidemiology
19.
J Virol ; 75(18): 8356-67, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11507181

ABSTRACT

Segment 5 of bluetongue virus (BTV) serotype 10, which encodes the outer capsid protein VP5, was tagged with glutathione S-transferase and expressed by a recombinant baculovirus. The recombinant protein was subsequently purified to homogeneity, and its possible biological role in virus infection was investigated. Purified VP5 was able to bind mammalian cells but was not internalized, which indicates it is not involved in receptor-mediated endocytosis. The purified VP5 protein was shown to be able to permeabilize mammalian and Culicoides insect cells, inducing cytotoxicity. Sequence analysis revealed that VP5 possesses characteristic structural features (including two amino-terminal amphipathic helices) compatible with virus penetration activity. To assess the role of each feature in the observed cytotoxicity, a series of deleted VP5 molecules were generated, and their expression and biological activity was compared with the parental molecule. VP5 derivatives that included the two amphipathic helices exhibited cytotoxicity, while those that omitted these sequences did not. To confirm their role in membrane destabilization two synthetic peptides (amino acids [aa] 1 to 20 and aa 22 to 41) encompassing the two helices and an additional peptide representing the adjacent downstream sequences were also assessed for their effect on the cell membrane. Both helices, but not the downstream VP5 sequence, exhibited cytotoxicity with the most-amino-terminal helix (aa 1 to 20) showing a higher activity than the adjacent peptide (aa 22 to 41). Purified VP5 was shown to readily form trimers in solution, a feature of many proteins involved in membrane penetration. Taken together, these data support a role for VP5 in virus-cell penetration consistent with its revelation in the entry vesicle subsequent to cell binding and endocytosis.


Subject(s)
Bluetongue virus , Capsid/physiology , Cell Membrane Permeability/physiology , Animals , Binding Sites , Capsid/chemistry , Capsid/genetics , Capsid/metabolism , Capsid Proteins , Cell Line , Cell Membrane/physiology , Chlorocebus aethiops , Cricetinae , Gene Expression , Mice , Oligopeptides , Peptides , Protein Structure, Secondary , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/metabolism , Recombinant Fusion Proteins/physiology , Solutions , Time Factors , Vero Cells
20.
J Gen Virol ; 80 ( Pt 8): 1889-1897, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10466784

ABSTRACT

In the course of experiments designed to assess the potential role of alternative open reading frames (ORF) present in the 5'-terminal untranslated region (5'-UTR) of poliovirus type 1 (Mahoney strain) genomic RNA, we came across a double mutation that completely abrogated the infectivity of full-length cDNA clones. The infectivity was rescued in trans by cotransfecting COS-1 cells with short RNA transcripts of the wild-type 5'-UTR of poliovirus type 2 Lansing, provided a free 3'-OH was available. Direct sequencing of the viral RNA revealed that the infectious viruses recovered were recombinants Lansing/Mahoney, with variable points of 'crossing-over'. A novel mechanism of RNA-RNA recombination, which we propose to call 'primer alignment-and-extension', is described that would explain the high rate of recombination of RNA viruses observed in natural conditions.


Subject(s)
Poliovirus/genetics , RNA, Viral , Recombination, Genetic , 5' Untranslated Regions , Animals , Base Sequence , COS Cells , Chlorocebus aethiops , Cloning, Molecular , Codon, Initiator , DNA, Complementary , DNA, Viral , Genome, Viral , Humans , Molecular Sequence Data , Mutagenesis , Protein Biosynthesis , RNA , Transfection , Vero Cells , Virion
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